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  • Bone
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  • Electronic Resource  (16,408)
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  • 1
    Electronic Resource
    Electronic Resource
    The biochemistry of ancient DNA in bone (1994)
    Springer
    Cellular and molecular life sciences 50 (1994), S. 530-535 
    Details
    ISSN: 1420-9071
    Keywords: Bone ; collagen ; fulvic acids ; DNA ; ancient DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The amount of DNA in ancient bone was determined by ethidium bromide staining after the removal of the potent Taq inhibitor, fulvic acid. A complete decalcification and a perfusion protocol were used to recover DNA from bone. A variety of purification techniques including molecular sieve, hydroxyapatite binding and ‘Magic’ preparations yielded DNA that spanned from 3.4μg/g of bone to below detectable limits. Fulvic acid was shown to interfere with the quantification of DNA derived from ancient human skeletal material one hundred to over seven thousand years old. Scanning UV in the 300 to 230 nm range is a simple and sensitive technique for documenting fulvic acid contamination in ancient bone extracts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01921721
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of homocysteine thiolactone and its alpha methylated derivative on bone matrix in the mouse (1994)
    Springer
    Amino acids 6 (1994), S. 199-203 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Homocysteine thiolactone ; Alpha-homocysteine thiolactone ; Bone ; Glycosaminoglycans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Homocysteine (HC) is a radiation protector but toxic to bone. Its derivative homocysteine thiolactone (HCTL) and the alpha-alkylated analogue (A-methyl-HCTL) was fed to mice for a period of six weeks in a daily dose of 50 mg/kg body weight. Parameters for bone matrix as collagen content, acid solubility of bone collagen, urinary bone collagen cross links (pyridinolines) and urinary acid glycosaminoglycans were determined. Urinary acid glycosaminoglycans were significantly reduced in the HCTL treated group but not in the alpha-methyl-homocysteine thiolactone (A-methyl-HCTL) group (controls: 45 ± 7 mg/mmol creatinine, homocysteine thiolactone 38 ± 5 mg/mmol creatinine, A-methyl HCTL 45 ± 6 mg/mmol creatinine). No differences were found for the parameters of bone collagen between the groups. The potent radiation protecting methylated derivative therefore did not change bone matrix and should be a candidate for further toxicological studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00805847
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  • 3
    Electronic Resource
    Electronic Resource
    The time course of renal function and bone turnover in parathyroid crisis due to intratumoral hemorrhage (1994)
    Springer
    Journal of molecular medicine 72 (1994), S. 448-450 
    Details
    ISSN: 1432-1440
    Keywords: Parathyroid ; Crisis ; Kidney ; Bone ; Turnover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Parathyroid crisis occurring in primary hyperparathyroidism is characteized by extremely high circulating levels of parathyroid hormone and acute onset of severe hypercalcemia. We describe a 62-year-old woman with parathyroid crisis probably due to an intraturnoral hemorrhage. Renal dysfunction reduced the effectiveness of preoperative management and continued to deteriorate for 5 days after parathyroidectomy. The normalization of serum calcium after parathyroidectomy delayed and it took 6 days. Maintenance of renal function is important for pre- and postoperative courses of the present case. The rapid decrease in serum parathyroid hormone after parathyroidectomy was followed by a rapid and transient (about fivefold) increase in serum alkaline phosphatase with peak value on the 10th postoperative day. This indicated that reversal phase from bone resorption (accelerated by parathyroid hormone) to bone formation lasted about 10 days under the conditions of the present case.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180519
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  • 4
    Electronic Resource
    Electronic Resource
    Comparison of DNA extraction and amplification from ancient human bone and mummified soft tissue (1994)
    Springer
    International journal of legal medicine 107 (1994), S. 152-155 
    Details
    ISSN: 1437-1596
    Keywords: Ancient DNA ; Bone ; Soft tissue ; Automated DNA extraction ; PCR ; Sex determination ; alte DNA ; Knochen ; Weichgewebe automatisierte ; DNA-Extraktion ; PCR Geschlechtsbestimmung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung Für eine vergleichende Untersuchung von Knochen und Weichgewebe als Quellenmaterial für DNA-Analysen wurden südamerikanische, präkolumbische, männliche Mumien verwendet. Die Eignung der DNA-Extrakte beider Quellen wurde über ihre Effektivität als Ziel-DNA in PCR-Amplifikationen bewertet. Die Ergebnisse zeigen, daß bei Verwendung stark degradierten Materials Knochen den Weichgeweben für PCR-Analysen vorzuziehen sind. Dies scheint unabhängig von der spezifischen anatomischen Herkunft der Proben zu sein.
    Notes: Abstract South american precolumbian male mummies were employed as source material for a comparative investigation of bone and soft tissues by DNA analysis. The suitability of the DNA extracts from both sources was tested and evaluated by their effectiveness as target DNA in PCR amplifications. The results suggest that skeletal material should be given preference over soft tissues for PCR analysis if the material is severely degraded. This seems to be independent of the specific anatomical origin of the samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01225603
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  • 5
    Electronic Resource
    Electronic Resource
    Purification of mineralized tissue-associated osteopontin (1994)
    Springer
    Methods in cell science 16 (1994), S. 211-215 
    Details
    ISSN: 1573-0603
    Keywords: Bone ; Bone sialoprotein ; Osteopontin ; Protein purification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A protocol to extract and purify osteopontin, a protein with cell adhesion and mineral-crystal binding properties, from mineral-associated tissues is described. This procedure provides for the complete separation of osteopontin from bone sialoprotein, a mineralized tissue-specific protein with similar properties to that of osteopontin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01540653
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  • 6
    Electronic Resource
    Electronic Resource
    Three-dimensional photographic study of cancellous bone in human fourth lumbar vertebral bodies (1994)
    Springer
    Anatomy and embryology 189 (1994), S. 259-274 
    Details
    ISSN: 1432-0568
    Keywords: Bone ; Cancellous ; Trabecular ; Age ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In an analysis of the 3D architecture of cancellous bone, two-dimensional techniques are of limited value. A simple technique employing stereophotographs of whole sections of lumbar vertebrate made possible a detailed description of the 3D structure of the normal fourth lumbar vertebral body and its changes with ageing and osteoporosis. Parallax measurements were used to calculate the real lengths of horizontal trabeculae. The bone presented a continuous spectrum of microstructure, from a honeycomb of tubes, to plates and braces and, finally, fragile rods. A distinct pattern was produced in osteoporotic samples by the removal of horizontal and selected vertical trabeculae followed by a thickening of the remaining vertical trabeculae in the peripheral regions. Very long, thin horizontal trabeculae were formed in all three zones (superior, middle and inferior) during this process. The observation of porotic architecture in intact specimens points to the inadequacy of the clinical criterion of the occurrence of a fracture in judging the osteoporotic state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239013
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  • 7
    Electronic Resource
    Electronic Resource
    Simulation of bone resorption-repair coupling in vitro (1994)
    Springer
    Anatomy and embryology 190 (1994), S. 339-349 
    Details
    ISSN: 1432-0568
    Keywords: Osteoclasts ; Osteoblasts ; Resorption ; Remodelling ; Dentine ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In the normal adult human skeleton, new bone formation by osteoblasts restores the contours of bone surfaces following osteoclastic bone resorption, but the evidence for resorption-repair coupling remains circumstantial. To investigate whether sites of prior resorption, more than the surrounding unresorbed surface, attract osteoblasts or stimulate them to proliferate or make new matrix, we developed a simple in vitro system in which resorption-repair coupling occurs. Resorption pits were produced in mammalian dentine or bone slabs by culturing chick bone-derived cells on them for 2–3 days. The chick cells were swept off and the substrata reseeded with rat calvarial osteoblastic cells, which make bone nodules in vitro, for periods of up to 8 weeks. Cell positions and new bone formation were investigated by ordinary light microscopy, fluorescence and reflection confocal laser microscopy, and SEM, in stained and unstained samples. There was no evidence that the osteoblasts were especially attracted to, or influenced by, the sites of resorption in dentine or bone before cell confluence was reached. Bone formation was identified by light microscopy by the accumulation of matrix, staining with alizarin and calcein and by von Kossa's method, and confirmed by scanning electron microscopy (SEM) by using backscattered electron (BSE) and transmitted electron imaging of unembedded samples and BSE imaging of micro-milled embedded material. These new bone patches were located initially in the resorption pits. The model in vitro system may throw new light on the factors that control resorption-repair coupling in the mineralised tissues in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00187292
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  • 8
    Electronic Resource
    Electronic Resource
    Ectopic ossicles associated with metacercariae of Apophallus brevis (Trematoda) in yellow perch, Perca ftavescens (Teleostei): development and identification of hone and chondroid bone (1994)
    Springer
    Anatomy and embryology 190 (1994), S. 29-46 
    Details
    ISSN: 1432-0568
    Keywords: Ectopic ossification ; Ossicles ; parasite infection ; Chondroid bone ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This paper describes the development and tissues in mineralized ossicles in the musculature of Perca flavescens infected with metacercariae of the trematode Apophallus brevis. Analysis involved light microscopy, transmission and scanning electron microscopy, X-ray scanning electron microprobe analysis, and tetracycline labelling. Two to 14 days post-infection, fibroblast-like host cells stream towards the parasite cyst forming a fusiform cellular capsule. By 14 days post-infection the capsule differentiates into an inner hypertrophied layer, an extensive middle layer of fibroblast-like cells, and a thin outer layer of flattened fibroblast-like cells forming a fibrous sheath at the capsule/muscle interface. From 21–35 days post-infection, a bony tissue is deposited periosteally in an equatorial ring around the cyst. With time, additional tissue is secreted over the ring increasing its thickness and advancing the matrix front towards the poles of the ossicle. Plump osteoblast-like cells cover the developing ossicle and may become trapped within the matrix in lacunae encapsulated by collagen. By 63 days post-infection, medium-sized ossicles are morphologically similar to large cysts from perch captured in the wild; ovoid with two polarized canals, but lacking acellular or lamellar bone-like tissue. Mineralized ossicles contain calcium, phosphorus and oxygen. Large ossicles retrieved from perch given multiple doses of tetracycline revealed discrete fluorescent bands, indicative of incremental growth. Fully developed ossicles are composed of two skeletal tissues, an inner region of chondroid bone and an outer region of acellular, lamellar bone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00185844
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  • 9
    Electronic Resource
    Electronic Resource
    A study of the nutrient foramina of lower limb long bones (1994)
    Springer
    Surgical and radiologic anatomy 16 (1994), S. 409-412 
    Details
    ISSN: 1279-8517
    Keywords: Nutrient foramina ; Bone ; Lower limb
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les foramens nourriciers de 269 os longs de membres inférieurs d'adultes ont été étudiés afin d'en préciser le nombre et le siège. L'index foraminal moyen était de 48,82 pour le fémur, 33,17 pour le tibia, 47,82 pour la fibula. Sur le fémur, les foramens sont le plus souvent doubles, situés au tiers moyen de la ligne âpre. Sur le tibia, le foramen est le plus souvent au tiers supérieur de la face postérieure. Enfin sur la fibula, il se situe en général au tiers moyen de face postérieure.
    Notes: Summary In this study a total of 269 adult lower limb long bones were examined to determine the number and location of the nutrient foramina in the shafts of bones. The mean of foraminal index was 48.82 for femur, 33.17 for tibia, and 47.82 for fibula. The number of foramina noted were: two on the linea aspera in the middle third of the femur, one on the posterior surface of the upper third of the tibia, and one on the posterior surface of the middle third of the fibula.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01627662
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of magnesium deficiency on strength, mass, and composition of rat femur (1994)
    Springer
    Calcified tissue international 54 (1994), S. 44-49 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Stress ; Elasticity ; Mechanical properties ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Magnesium (Mg) participates in the normal formation and remodeling of bone. However, little is known about effects of Mg status on the biomechanical function of bone. We examined gross morphometry and composition as well as biomechanical properties of the femurs of male rats fed diets adequate or deficient in Mg. Comparison of deficient animals and controls yielded a number of differences (all significant at P〈0.05). Mg-depleted animals exhibited slow growth, inefficient food utilization, and greatly reduced concentrations of Mg in both serum and femur ash. Compared with controls, femurs from depleted animals were shorter, but wet weights, diameters, and midfemoral cross-sectional areas showed no differences. Bone length was reduced to a greater degree than could be accounted for by differences in body weights between the groups. Bones of Mg-deficient rats contained less dry matter and less ash (which contained more Ca/g) than those of controls, along with a higher percentage of moisture. Significantly reduced bone strength in depleted animals was evident from the lighter loads supported at the elastic limit (yield point) and at fracture and from decreased stresses accompanying those loads. Modulus of elasticity, however, was not affected by Mg depletion. Different yield and breaking loads were related to different body weights of groups, but stresses were reduced for deficient bones even after adjusting for body size. Our data establish abnormal biomechanical behavior of cortical bone in Mg-deficient animals and emphasize the importance of measuring such functional properties of bone in the assessment of responses to altered metabolic conditions under experimental conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316289
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  • 11
    Electronic Resource
    Electronic Resource
    Broadband ultrasonic attenuation imaging: A new imaging technique of the os calcis (1994)
    Springer
    Calcified tissue international 54 (1994), S. 83-86 
    Details
    ISSN: 1432-0827
    Keywords: Ultrasound attenuation ; Bone ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Ultrasound transmission measurement through the os calcis is an emerging technique and a promising clinical tool for early assessment of osteoporosis. However, several previous studies showed that broadband ultrasonic attenuation (BUA) is sensitive to small variations in bone mass or structure. The os calcis is an inhomogeneous bone and therefore, the attenuation depends on the location in the os calcis. BUA distribution within the os calcis can be measured by rectilinear scanning over the entire bone. We used a mechanical scanning device with both unfocused and focused transducers. The spatial resolution of these was about 25 mm and 4 mm, respectively. There was good agreement (r=0.97) between the results with unfocused and focused transducers. In addition, imaging the variations of BUA is possible with the focused transducers, and high quality images are obtained. These images permit the selection of optimal regions of interest for ultrasound attenuation measurement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296055
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  • 12
    Electronic Resource
    Electronic Resource
    Age-dependence of bone material quality shown by the measurement of frequency of resonance in the ulna (1994)
    Springer
    Calcified tissue international 54 (1994), S. 96-100 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Material quality ; Sound transmission ; Frequency of resonance ; Age ; Bone width
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract In women before and after the age of peak bone mass, identical values of bone mineral density (BMD) can be obtained. However, there is a much higher incidence of osteoporotic fractures in older women. We investigated whether a deterioration of bone material quality with increasing age might contribute to this phenomenon. Material properties of bone tissue can be characterized by the modulus of elasticity, which is correlated to the square of sound transmission velocity. In this study, sound transmission velocity was determined in cortical bone by measuring the frequency of resonance in the ulna in the direction of the bone's longitudinal axis and correcting the values by multiplying by ulna length. Validation of this method indicated acceptable reproducibility: interobserver variability determined as the mean coefficient of variation was 1.82%. In a clinical study, 21 young women (22.5±1.2 years old) were compared with 21 middle-aged women (52.9±2.7 years old). Pairs were matched that had identical values of BMD in the nondominant forearm at a location representing mainly cortical bone (SPA). The product of ulna length and frequency of resonance in the ulna in the younger women was found to be 61.4±5.8 m/second, and in the middle-aged women 55.7±4.5 m/second. The difference was highly significant with P〈0.005. Our results confirm recent findings indicating a deterioration of bone material quality independent of BMD with increasing age. As shown by comparing ulna width at the site of measurement of bone mineral density between both groups of women, the deterioration of bone material quality in ulnar cortical bone with increasing age might at least in part be functionally compensated by an increase of the moment of inertia due to greater bone width [8, 10].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296058
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  • 13
    Electronic Resource
    Electronic Resource
    Helodermin, helospectin, and PACAP stimulate cyclic AMP formation in intact bone, isolated osteoblasts, and osteoblastic cell lines (1994)
    Springer
    Calcified tissue international 54 (1994), S. 284-289 
    Details
    ISSN: 1432-0827
    Keywords: Helodermin ; Bone ; Cyclic AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Helodermin and helospectin are peptides structurally similar to vasoactive intestinal polypeptide (VIP) which were recently isolated from the salivary gland venom of the lizard Heloderma suspectum. Pituitary adenylate cyclaseactivating polypeptide (PACAP) has been isolated from ovine hypothalamus and also shows sequence homology to VIP. A helodermin-like peptide has been detected by combined immunohistochemical and immunochemical techniques in the thyroid C-cells. In the present study, lizard helodermin was found to cause a time- and dose-dependent stimulation of cyclic AMP (cAMP) formation in neonatal mouse calvarial bones. Also, helospectin I, PACAP 27, and the C-terminally extended PACAP 38 stimulated cAMP accumulation in the mouse calvariae. The cAMP rise in response to helodermin was comparable to that induced by VIP, both in terms of potency and magnitude of the response. Helodermin, helospectin I, PACAP 27, and PACAP 38, at concentrations of 1 μmol/liter, stimulated cAMP accumulation in enzymatically isolated mouse calvarial bone cells. A significant response to all peptides was observed in both early and late released bone cells isolated from the calvariae, with low and high alkaline phosphatase activity, respectively. Helodermin and VIP stimulated cAMP accumulation in the cloned mouse calvarial osteoblastic cell line MC3T3-E1, in rat (UMR 106-01), and human (Saos-2) osteoblastic osteosarcoma cell lines, but not in the rat osteosarcoma cell line ROS 17/2.8. The effect of helodermin was synergistically and dose-dependently enhanced by forskolin (0.1 and 1 μmol/liter). These data show that bone cells, including osteoblasts, respond to several peptides of the VIP family, including helodermin, helospectin I, PACAP 27, and PACAP 38. Whether the responses are mediated via one or several receptor populations remains to be established. The finding that VIP and helodermin, at maximally effective concentrations, did not cause additive effect on cAMP formation in intact mouse calvariae suggests that these two agonists may use a common receptor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00295952
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  • 14
    Electronic Resource
    Electronic Resource
    Human recombinant interleukin-1 receptor antagonist blocks bone resorption induced by interleukin-1β but not interleukin-1α (1994)
    Springer
    Calcified tissue international 55 (1994), S. 12-15 
    Details
    ISSN: 1432-0827
    Keywords: IL-1α ; IL-1β ; IL-1 receptor antagonist ; Bone ; Calcium ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Both interleukin-1α (IL-1α) and interleukin-1β (IL-1β) are powerful stimulators of bone resorption in vivo and in vitro. Interleukin-1 receptor antagonist (IL-1ra) binds to many interleukin-1 receptors. It does not activate the receptor and effectively blocks the action of IL-1α and IL-1β. In this study, human recombinant IL-1ra, at 100-fold excess, was found to block bone resorption in cultured mouse calvaria due to IL-1β but not IL-1α. These observations may be explained by differential affinities of receptors for IL-1α, IL-1β and rhIL-1ra on target bone cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00310162
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  • 15
    Electronic Resource
    Electronic Resource
    Combined magnetic fields increased net calcium flux in bone cells (1994)
    Springer
    Calcified tissue international 55 (1994), S. 376-380 
    Details
    ISSN: 1432-0827
    Keywords: Electromagnetic ; Bone ; Calcium ; Osteoblast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Low energy electromagnetic fields (EMF) exhibit a large number of biological effects. A major issue to be determined is “What is the lowest threshold of detection in which cells can respond to an EMF?” In these studies we demonstrate that a low-amplitude combined magnetic field (CMF) which induces a maximum potential gradient of 10-5 V/m is capable of increasing net calcium flux in human osteoblast-like cells. The increase in net calcium flux was frequency dependent, with a peak in the 15.3–16.3 Hz range with an apparent bandwidth of approximately 1 Hz. A model that characterizes the thermal noise limit indicates that nonspherical cell shape, resonant type dynamics, and signal averaging may all play a role in the transduction of lowamplitude EMF effects in biological systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00299318
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  • 16
    Electronic Resource
    Electronic Resource
    Contribution of collagen and mineral to the elastic anisotropy of bone (1994)
    Springer
    Calcified tissue international 55 (1994), S. 381-386 
    Details
    ISSN: 1432-0827
    Keywords: Acoustic microscopy ; Bone ; Collagen fiber ; Elastic anisotropy ; Mineral crystal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract It has long been thought that collagen fibers within the bone matrix are deposited in an aligned pattern that channels mineral growth. If this model of bone structure is correct, both organic and inorganic phases of bone should have similar elastic anisotropy. Using an acoustic microscope, we measured longitudinal and transverse acoustic velocities of cortical specimens taken from 10 dog femurs before and after removal of either the mineral (using 10% EDTA) or collagen phases (using 7% sodium hypochlorite) and calculated longitudinal (CL) and transverse (CT) elastic coefficients. The anisotropy ratio (CL/CT) decreased significantly after demineralization (1.61 before versus 1.06 after, P〈0.0001, paired t-test). However, there was no significant change after decollagenization (1.51 before versus 1.48 after, P=0.617, paired t-test). We conclude that the orientation of mineral crystals is the primary determinant of bone anisotropy, and the collagen matrix within osteonal bone has little directional orientation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00299319
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  • 17
    Electronic Resource
    Electronic Resource
    Magnesium distribution in human bone (1994)
    Springer
    Calcified tissue international 54 (1994), S. 34-37 
    Details
    ISSN: 1432-0827
    Keywords: Magnesium ; Bone ; Aging ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The present study was undertaken to reveal the magnesium distribution in human bone. Sixty human ribs, obtained from subjects aged 10–80 years of age, were used. Transverse sections were prepared from the middle region of the human ribs. Adjacent sections were ground to a thickness of about 1000 μm. One section was used for magnesium determination by atomic absorption spectrophotometry, and the other was used for analysis with X-ray microanalysis. Thirty micron thick samples were abraded continuously from the periosteal and the endosteal surfaces by abrasive microsampling, as previously described by Weatherell et al. [3]. Results showed that magnesium concentrations were higher in both the periosteal and endosteal surfaces and did not change with age in general, although it tended to be higher among teenagers and lower over 80 years old.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316287
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  • 18
    Electronic Resource
    Electronic Resource
    Antiresorptive drugs and trabecular bone turnover: Validation and testing of a computer model (1994)
    Springer
    Calcified tissue international 54 (1994), S. 179-185 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Drugs ; Trabecular ; Turnover ; Computer ; Model ; Sensitivity ; Activation frequency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract A computer model of trabecular bone turnover has been developed, based on concepts of Jonathan Reeve [1]. This model predicts changes in bone volume by summing bone resorption and formation over a large number of remodeling sites. Clinical data [histomorphometry and bone mineral content (BMC)] from two clinical studies using an antiresorptive drug (etidronate disodium, EHDP) in post-menopausal osteoporosis were used to test the model. The results for BMC obtained from the EHDP and placebo groups in each study at 60 and 120 weeks were correctly predicted by the model from the histomorphometric data obtained from baseline and week 60 biopsies. The parameter in this model having the greatest influence on predicted changes in bone volume was found by sensitivity analysis to be activation frequency. These results suggest that the contribution of bone turnover to BMC can be predicted solely by considering the cell kinetics of the basic multicellular unit (BMU), and that, in the case of antiresorptive drugs, maximal effects on bone volume may be achieved by pharmacological reduction of activation frequency. The results also suggest that the present model may be useful in predicting in clinical studies the effects of EHDP and similar drugs on bone turnover.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00301675
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  • 19
    Electronic Resource
    Electronic Resource
    Intact serum parathyroid hormone levels increase during running exercise in well-trained men (1994)
    Springer
    Calcified tissue international 54 (1994), S. 256-261 
    Details
    ISSN: 1432-0827
    Keywords: Calcium ; Lactate ; Acidosis ; Treadmill ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The purpose of this study was to examine the influence of exercise on the serum concentrations of intact parathyroid hormone (PTH). Serum PTH and plasma lactate were measured in 15 well-trained men, 9 long-distance runners and 6 fire-fighters, during two running exercises. Test one consisted of 40-minute treadmill running with a stepwise increased load and test two consisted of 50-minute treadmill running with a constant velocity. When the load was step-wise increased, the PTH concentrations increased moderately at the slower running paces but reached a final value that was about 50% higher than the starting value. This rise occurred despite a concomitant increase of total serum calcium from 2.38±0.06 to 2.49±0.05 mmol/liter (P〈0.01). During the constant running exercise, the long-distance runners, but not the fire-fighters, displayed a significant increase in PTH concentrations although the rise in total serum calcium was similar in both groups. There was a weak correlation between the changes in PTH and lactate in both exercises. The findings demonstrate that both high and low intensity exercise enhance release of PTH in long-distance runners through a mechanism that does not involve serum calcium. This relationship might be of importance for bone mass in men performing long-distance training.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00295947
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  • 20
    Electronic Resource
    Electronic Resource
    Lower extremity stress fractures during intermittent cyclical etidronate treatment for osteoporosis (1994)
    Springer
    Calcified tissue international 54 (1994), S. 431-434 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Diphosphonate ; Osteoporosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract During intermittent cyclical etidronate treatment, a lower extremity pain syndrome associated with stress fractures was observed in three osteoporotic patients. This report describes the development of stress fractures during initial cycles of treatment, with recurrence of symptoms in two patients when etidronate therapy was resumed. Further studies are needed to confirm whether stress fractures are associated with cyclic etidronate treatment and if so, the incidence and pathophysiology need to be determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305532
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  • 21
    Electronic Resource
    Electronic Resource
    The modulatory effect of endogenous parathyroid hormone on the action of hydrochlorothiazide in pseudohypoparathyroidism type I (1994)
    Springer
    Calcified tissue international 54 (1994), S. 473-476 
    Details
    ISSN: 1432-0827
    Keywords: Pseudohypoparathyroidism ; Thiazide ; Kidney ; Bone ; Parathyroid hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract We compared the effect of orally administered 100 mg of hydrochlorothiazide (HCTZ) among eight patients with pseudohypoparathyroidism (PHP) type I, 11 patients with idiopathic hypoparathyroidism (IHP), and 12 patients with primary hyperparathyroidism (1oHPT). Patients with PHP type I or with IHP were studied during the treatment with 1α-hydroxylated metabolites of vitamin D3. HCTZ raised serum levels of calcium (Ca) in 1oHPT (P〈0.001) and PHP type I (P〈0.01) but did not increase urinary excretion of Ca. Serum parathyroid hormone (PTH) in PHP type I decreased (P〈0.02) after HCTZ administration in response to the increase in serum Ca. HCTZ did not raise serum levels of Ca in IHP but increased urinary excretion of Ca in this group (P〈0.01). HCTZ suppressed tubular reabsorption of phosphate (P) in IHP (P〈0.01) and 1oHPT (P〈0.05) but not in PHP type I. Urinary excretion of cAMP did not change after HCTZ administration in PHP type I, IHP, or 1oHPT. Endogenous PTH modulated the effects of HCTZ on Ca mobilization from bone and renal reabsorption of Ca in PHP type I with normal or high serum levels of PTH and in 1oHPT with high serum levels of PTH. The inhibitory effect of HCTZ on renal tubular reabsorption of P (probably from proximal tubules) was independent of PTH. The resistance to this inhibitory effect of HCTZ on P reabsorption in PHP type I suggested a proximal tubular dysfunction in this disorder.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334326
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  • 22
    Electronic Resource
    Electronic Resource
    Selective extractability of noncollagenous proteins from chicken bone (1994)
    Springer
    Calcified tissue international 55 (1994), S. 230-235 
    Details
    ISSN: 1432-0827
    Keywords: Noncollagenous ; Proteins ; Bone ; Sialo-protein ; Osteopontin ; Osteocalcin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Quantitative analyses of a wide variety of different solvents used for the extraction of several of the noncollagenous proteins of fully mineralized chicken bone powder were carried out to compare both the effectiveness of various procedures and the distribution of specific proteins which were solubilized. Extraction procedures included solutions of 6 M guanidine-HCl, pH 7.0, 0.5 M EDTA, pH 7.4, 0.3 N citric acid, 0.3 N HCl, 0.3 N formic acid, and 0.3 N acetic acid. Chelation of calcium ions by EDTA and dissolution of the mineral phase by acid extraction released 95% or more of the total calcium content of the bone powder by 48 hours, guanidine-HCl released less than 20% or less of the total calcium content even when extraction was carried out by 168 hours. Moreover, although guanidine-HCl solubilized a significant amount of collagen as gelatin, essentially none of the phosphoproteins, osteocalcin, or the proteoglycan decorin were solubilized, as detected by immunological techniques. In contrast, extraction of the mineralized bone powder by HCl and formic acid was very efficient in selectively solubilizing osteocalcin and osteopontin, while bone sialoprotein was selectively released by EDTA, and solubilized to a lesser extent by formic acid. Similarly, EDTA selectively removed decorin compared with HCl, formic, acetic, or citric acids. Only small amounts of osteopontin and osteocalcin were detected in the acetic acid extracts. These results provide methods for the selective solubilization of several different major, noncollagenous proteins from mineralized bone which should significantly aid in maximizing the amount of the specific protein recovered, and the ease with which the various proteins can be purified. The data also provide some insight into the intrinsic solubility characteristics of collaten, the specific noncollagenous proteins, and their potential association with each other and the mineral phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425880
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  • 23
    Electronic Resource
    Electronic Resource
    Effects of infusion of parathyroid hormone and primary hyperparathyroidism on formation and breakdown of type I collagen (1994)
    Springer
    Calcified tissue international 55 (1994), S. 412-416 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Biochemical markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract The influence of chronic and acute exposure to parathyroid hormone (PTH) on formation and breakdown of type I collagen, using two recently developed radioimmunoassays for serum PICP (the carboxyterminal propeptide of type I procollagen) and serum ICTP (the carboxyterminal telopeptide of type I collagen), have been evaluated. Fasting morning values were obtained from 18 women with primary hyperparathyroidism (HPT) and an equal number of age-matched, healthy controls. A 24-hour infusion of synthetic human parathyroid hormone (PTH 1-38) was performed in 14 healthy females. The patients with HPT had higher values for serum ICTP than the controls (6.0±3.0 and 4.1±2.1 μg/liter; P〈0.05), whereas the serum PICP concentrations were not different (170±72 and 151±65 μg/liter; n.s.). During infusion of PTH in healthy subjects, there was an increase of the serum ICTP concentrations (from 3.6±1.3 to 4.4±1.8 μg/liter; P〈0.001) whereas those of serum PICP decreased (from 185±78 to 118±42 μg/liter; P≤0.0001). The increase of serum ICTP during infusion of PTH was positively related to the increase of serum calcium and other indices of bone resorption, i.e., fasting urinary excretions of hydroxyproline and calcium. The decrease of serum PICP was also related to the changes of serum ICTP and hydroxyproline in urine, serum calcium, and alkaline phosphatase but not to osteocalcin, an established marker of osteoblastic activity. The findings support the fact that serum ICTP is a valuable method for evaluating bone resorption and is also easy to perform. Furthermore, the discordant results for the different markers of osteoblastic activity indicat that they reflect different functions of the cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298553
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  • 24
    Electronic Resource
    Electronic Resource
    Dietary variation in arctic foxes (Alopex lagopus)-an analysis of stable carbon isotopes (1994)
    Springer
    Oecologia 99 (1994), S. 226-232 
    Details
    ISSN: 1432-1939
    Keywords: Carbon isotopes ; Arctic fox ; Diet ; Bone ; Collagen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We used stable carbon isotopes to analyse individual variation in arctic fox diet. We extracted collagen from bones (the lower jaw), and measured stable carbon isotopes. The foxes came from three different localities: Iceland, where both microtines and reindeer are rare; west Greenland, where microtines are absent; and Sweden, where scat analyses showed the primary food to be microtine rodents and reindeer. The Icelandic samples included foxes from both coastal and inland habitats, the Swedish sample came from an inland area, and the Greenland sample from coastal sites. The spatial variation in the isotopic pattern followed a basic division between marine and terrestrial sources of protein. Arctic foxes from inland sites had δ13C values of −21.4 (Iceland) and −20.4‰ (Sweden), showing typical terrestrial values. Coastal foxes from Greenland had typical marine values of −14.9‰, whereas coastal foxes from Iceland had intermediate values of −17.7‰. However, there was individual variation within each sample, probably caused by habitat heterogeneity and territoriality among foxes. The variation on a larger scale was related to the availability of different food items. These results were in accordance with other dietary analyses based on scat analyses. This is the first time that stable isotopes have been used to reveal individual dietary patterns. Our study also indicated that isotopic values can be used on a global scale.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00627734
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  • 25
    Electronic Resource
    Electronic Resource
    Présentation de la série du GECO de métastases osseuses des membres : 90 cas (1994)
    Springer
    European journal of orthopaedic surgery & traumatology 4 (1994), S. 21-21 
    Details
    ISSN: 1432-1068
    Keywords: Metastases ; Bone ; Métastases osseuses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Dans cette série de cas, vus par des chirurgiens, une métastase sur deux est traitée au stade de fracture. Une fracture sur deux est survenue en l'absence de toute symptomatologie évocatrice.
    Notes: Abstract This series of surgical patients shows that 50% of bony metastases are complicated by a fracture. Of these, 50% occurred without any preceding symptoms or signs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01806724
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  • 26
    Electronic Resource
    Electronic Resource
    Ostéolyse tumorale maligne métastatique Données actuelles sur la physiopathologie et le traitement (1994)
    Springer
    European journal of orthopaedic surgery & traumatology 4 (1994), S. 5-8 
    Details
    ISSN: 1432-1068
    Keywords: Bone ; Metastases ; Osteoclast ; Cytokines ; Métastases osseuses ; Ostéoclaste ; Cytokines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les métastases ostéolytiques des cancers sont à l'origine de douleurs et de fractures pathologiques responsables d'une importante invalidité altérant la qualité de survie des patients. Ces destructions osseuses sont dues à une augmentation de la résorption osseuse, liée à la stimulation des ostéoclastes par des médiateurs sécrétés localement par les cellules tumorales et médullaires. Les bisphosphonates, puissants agents anti-ostéoclastiques, ont une bonne efficacité sur les douleurs osseuses, la prévention des fractures et des épisodes hypercalcémiques.
    Notes: Abstract Osteolytic metastases are the cause of pain and pathological fractures with marked disability affecting the patient's quality of life. The bone destruction is due to an increase of bone resorption, linked to stimulation of osteoclasts by mediators secreted locally by tumour and medullary cells. Bisphosphonates, strong anti-osteoclastic agents, are effective for bone pain, prevention of fractures and the treatment of hypercalcaemic episodes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01806718
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  • 27
    Electronic Resource
    Electronic Resource
    Evolution du traitement des métastases osseuses (1994)
    Springer
    European journal of orthopaedic surgery & traumatology 4 (1994), S. 3-4 
    Details
    ISSN: 1432-1068
    Keywords: Metastases ; Bone ; Métastases osseuses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Le traitement des métastases osseuses a vu ses modalités évoluer en fonction d'améliorations obtenues dans la prise en charge du cancer primitif et en raison d'une meilleure compréhension des phénomènes biologiques constatés au niveau de l'os métastatique. Du simple traitement palliatif des douleurs osseuses, la thérapeutique s'est orientée vers la prévention des complications dégradantes que sont les fractures et les paraplégies. Des résultats intéressants sont obtenus actuellement par l'utilisation de traitements chimiques luttant contre l'ostéolyse métastatique.
    Notes: Abstract The treatment of bony metastases has developed due to improvements in the care of the primary cancer and due to a better understanding of the biological phenomenon in the metastasis. From simple palliative treatment of bone pain, treatment is now being directed towards the prevention of the complications of metastasis, such as fractures and paraplegia. Interesting results are currently being obtained by using chemotherapy for treatment of metastatic osteolysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01806717
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  • 28
    Electronic Resource
    Electronic Resource
    Evolution des conceptions en matière de radiothérapie des métastases osseuses (1994)
    Springer
    European journal of orthopaedic surgery & traumatology 4 (1994), S. 11-12 
    Details
    ISSN: 1432-1068
    Keywords: Radiotherapy ; Metastases ; Bone ; Radiothérapie ; Métastases osseuses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les techniques d'irradiation antalgique sont différentes s'il s'agit de métastases uniques (champs séparés) ou multiples (irradiation hémicorporelle antalgique). Un procédé original d'irradiation hémicorporelle précoce est décrit.
    Notes: Abstract Irradiation for bone pain depends on whether the metastasis is solitary (separate field) or disseminated (antalgic half body irradiation). A new original procedure of early halfbody irradiation is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01806720
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  • 29
    Electronic Resource
    Electronic Resource
    Métastases osseuses d'origine thyroïdienne (1994)
    Springer
    European journal of orthopaedic surgery & traumatology 4 (1994), S. 13-15 
    Details
    ISSN: 1432-1068
    Keywords: Thyroid ; Bone ; Metastases ; Métastases osseuses ; Thyroïde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé En 25 ans, 1061 cancers de la thyroïde ont été pris en charge. 42 patients étaient atteints de métastases osseuses, unique ou multiples. La forme histologique la moins métastasiante est le cancer papillaire qui de plus, survient chez les sujets jeunes. Deux stades doivent être différentiés dans la maladie métastasiante. La métastase osseuse, unique, est découverte à la scintigraphie, les radiographies sont normales, l'irradiation à l'iode éventuellement associée au cobalt peut la stériliser. La métastase osseuse est visible sur les radiographies, elle n'est pas unique, la scintigraphie objectivera d'autres foyers hyperfixants, le traitement chirurgical, palliatif, aura pour effet de réduire la taille tumorale pour que l'irradiation puisse la stériliser ainsi que les autres foyers fixants.
    Notes: Abstract Over 25 years, 1601 thyroid cancers were treated. 42 patients had solitary or multiple bony metastases. The least metastatic histological form is papillary cancer, which in addition occurs in young subjects. There are two stages of the metastatic disease. The solitary bony metastasis, discovered on scintigraphy with normal Xrays, may be effectively treated by irradiation with iodine with the possible addition of cobalt. Multiple metastases, visible on plain X-ray with other hyperfixation areas on scintigraphy, is best treated by palliative surgery to reduce size so that it can be sterilised by irradiation at the same time as other hyperfixation sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01806721
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  • 30
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    Aspects actuels de la prise en charge des métastases osseuses en milieu oncologique (1994)
    Springer
    European journal of orthopaedic surgery & traumatology 4 (1994), S. 9-10 
    Details
    ISSN: 1432-1068
    Keywords: Metastases ; Bone ; Métastases osseuses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'histo-pronostic, comme l'utilisation de marqueurs, sont des notions relativement nouvelles qui facilitent la prise en charge de certains cancers. Hormonothérapie et chimiothérapie doivent être discutées en fonction de leurs avantages et de leurs inconvénients. Toutes les ressources modernes contre la douleur doivent être utilisées.
    Notes: Abstract The histological prognosis and use of markers are new concepts, which are of value in managing some cancers. Hormonal therapy and chemotherapy should be considered, along with their advantages and disadvantages. All contemporary modalities of treatment against pain should be used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01806719
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  • 31
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    Electronic Resource
    Cystic angiomatosis of bone with sclerotic changes mimicking osteoblastic metastases (1994)
    Springer
    Skeletal radiology 23 (1994), S. 247-252 
    Details
    ISSN: 1432-2161
    Keywords: Cystic angiomatosis ; Hemangiomatosis ; Lymphangiomatosis ; Osteosclerosis ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Five unusual cases of cystic angiomatosis of bone which presented with the radiologic appearance of osteoblastic lesions are reported. Three patients were female (ages 37, 41, and 65 years) and two were male (ages 24 and 66 years). Although cystic angiomatosis of bone usually produces widespread osteolytic lesions with a honeycombed appearance in the skeletal system, multiple osteoblastic lesions mimicking metastatic osteoblastic carcinoma are sometimes seen. This radiological presentation has not been well emphasized in previous reports. Histologically, in addition to the angiomatous lesions, both mature thickened lamellar bone trabeculae and immature trabeculae of woven bone were found. In one of our patients, increasing density of the osteoblastic lesions was noted over time. One previous study has suggested that the age of the lesions of cystic angiomatosis is related to radiographic density. It is important to recognize this uncommon variant of cystic angiomatosis and to include this entity among the radiologic differential diagnoses when multiple osteoblastic lesions are encountered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02412356
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  • 32
    Electronic Resource
    Electronic Resource
    Immunologicalization of complement C1s and matrix metalloproteinase 9 (92kDa gelatinase/type IV collagenase) in the primary ossification center of the human femur (1994)
    Springer
    Cell & tissue research 277 (1994), S. 239-245 
    Details
    ISSN: 1432-0878
    Keywords: Bone ; Ossification ; Cartilage ; Matrix ; Chondrocytes ; Complement ; Matrix metalloproteinase ; Immunocytochemistry ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The first component of complement $$C\bar 1s$$ has been shown to degrade type I and type II collagens (Yamaguchi et al. 1990), the latter of which is a major constituent of the cartilage matrix. In order to understand the physiological roles of $$C\bar 1s$$ in cartilage resorption, the expression of C1s was examined by immunohistochemistry in the primary ossification center where the matrix is removed and replaced by bone marrow. Hypertrophic chondrocytes, endothelium and hematogenous elements in the capillary buds were intensely stained by a monoclonal antibody against C1s. Matrix metalloproteinase 9 (MMP-9, 92kDa gelatinase/type IV collagenase) was also immunolocalized in hypertrophic chondrocytes, mesenchymal cells in the primitive bone marrow and the cartilage matrix adjacent to the marrow. In addition, $$C\bar 1s$$ was found to activate the zymogen of MMP-9. These observations suggest that $$C\bar 1s$$ and MMP-9 coordinately participate in matrix degradation in cartilage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327771
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  • 33
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    Electronic Resource
    The effect ofin vitro fluoride ion treatment on the ultrasonic properties of cortical bone (1994)
    Springer
    Annals of biomedical engineering 22 (1994), S. 404-415 
    Details
    ISSN: 1573-9686
    Keywords: Bone ; Ultrasound ; Interfacial bonding ; Anisotropy ; Fluoride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract The mechanical properties of composites are influenced, in part, by the volume fraction, orientation, constituent mechanical properties, and interfacial bonding. Cortical bone tissue represents a short-fibered biological composite where the hydroxyapatite phase is embedded in an organic matrix composed of type I collagen and other noncollagenous proteins. Destructive mechanical testing has revealed that fluoride ion treatment significantly lowers theZ-axis tensile and compressive properties of cortical bone through a constituent interfacial debonding mechanism. The present ultrasonic data indicates that fluoride ion treatment significantly alters the longitudinal velocity in theZ-axis as well as the circumferential and radial axes of cortical bone. This suggests that the distribution of constituents and interfacial bonding amongst them may contribute to the anisotropic nature of bone tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02368247
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  • 34
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    Electronic Resource
    Statistical model of the habit and arrangement of mineral crystals in the collagen of bone (1994)
    Springer
    Journal of statistical physics 77 (1994), S. 125-143 
    Details
    ISSN: 1572-9613
    Keywords: Bone ; collagen ; Voronoi tesselations ; small-angle scattering ; structure function ; calcified tissue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Randomly colored space tesselations are considered as models for the mineral/organic structure of bone. First, it is shown that the structure function for such models is always proportional to the average form factor of the individual tiles and hence independent of the mineral density in the sample. Then the structure function is calculated for three such models: for model I, based on a hexagonal, and model 2, on a Poisson-Voronoi tesselation of the plane and for model 3, based on a random tesselation of the line. These results are compared to experimental structure functions measured by small-angle scattering and excellent agreement is obtained between model 2 and the bone from mice and rats, as well as between model 3 and calcified turkey leg tendon. Divergent conclusions following recent experiments by small-angle x-ray scattering and by electron microscopy are discussed in the light of these structural models and an explanation is proposed which might remove the discrepancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02186835
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  • 35
    Electronic Resource
    Electronic Resource
    Regional and age variations in growing tendon (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 221 (1994), S. 309-320 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gastrocnemius tendons of 10 White Leghorn chickens at 6, 8, and 12 weeks of age were divided into proximal, middle, and distal portions to assess regional variability in composition and growth. Body weight increases ∼ 150% during the period examined, whereas the lateral gastrocnemius muscle and tendon increase ∼ 193% and 227%, respectively. No significant changes in cellularity (DNA concentration) or hydroxypyridinium (OHP) crosslinks occur with increasing age. Hydroxyproline (HYP) concentration increases by 12 weeks of age, as hexuronate, glucosamine, and galactosamine decrease. Composition shows some regional variation: the distal region of the tendon has a lower HYP concentration, and increased GAGs and OHP crosslinks compared to either the proximal or middle regions, which do not differ from each other. The mean collagen fibril diameter increases with age, but the oldest tendons also contain more small diameter fibrils (〈40 nm). There is a unimodal fibril distribution at all three ages, although this has broadened by 12 weeks. The data from this study suggest that rapid tendon growth occurs throughout the time period examined and that changes characteristic of mature tendon, such as increased OHP crosslink concentration, have not yet developed in hatchlings because of the large amount of new tissue being produced. Whereas all three regions of the tendon are similar in size, composition of the distal region differs from that of the proximal and middle regions, suggesting that this portion of the tendon should be avoided when sampling a tendon. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052210306
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  • 36
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    Microscopic anatomy of pycnogonida: I. Cuticle, epidermis, and muscle (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 33-48 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The integument of Pycnogonida (Arthropoda) consists of an epicuticle decorated with tubercles and a filamentous coat, an exocuticle with a small number of ill-defined layers, and an endocuticle whose numerous layers are composed of conspicuously cross-banded fibrils. This cuticular periodicity, attributable to cross-linked chitin, has been observed previously in uncalcified and untanned cuticle of many lower crustaceans, especially branchiopods and copepods, and in scattered examples of thin respiratory or excretory cuticles of other arthropods. It is uniformly present in all representatives of all nine pycnogonid families examined to date. Stomodeal, proctodeal, and arthrodial cuticles are devoid of the endocuticular periodicity. The cuticle is decorated with sensory filaments and setae, but is more noteworthy for a dense coverage by glands, up to 1,400/mm2. Myocuticular junctions have desmosomal fine structure previously found only in chelicerates. Muscle fine structure is that of slow fibers with long sarcomeres and a high actin to myosin filament ratio, except for cardiac muscle, which has short sarcomeres. Among the arthropods, only merostomates resemble the pycnogonids in the lack of fast somatic muscle fibers. Pycnogonids display a hybrid array of fine structural features that variously serve to relate them to some arthropod subphyla and distance them from others. © 1994 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052220105
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  • 37
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    Erratum (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 111-111 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052220111
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    Development and growth of compound tooth plates in Callorhinchus milii (chondrichthyes, holocephali) (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 73-89 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The chimaeroid holocephalian fishes are distinguished among extant chondrichthyans by the possession of three pairs of tooth plates, evergrowing and partially hypermineralized, that are not shed and replaced like the teeth of living elasmobranchs. Although derivation of the chimaeroid tooth plate from the fusion of members of a plesiomorphic chondrichthyan tooth family has been proposed, evidence for this hypothesis has been lacking. A new analysis of the development and structure of the tooth plates in Callorhinchus milii (Holocephali, Chimaeriformes) reveals the compound nature of the tooth plates in a chimaeroid fish. Each tooth plate consists of an oral and aboral territory that form independently in the embryo and maintain separate growth surfaces through life. The descending lamina on the aboral surface of the tooth plate demarcates the growth surface of the aboral territory. Comparison with the tooth plates of Chimaera monstrosa indicates that compound tooth plates may be a feature of all chimaeroids in which a descending lamina is present. The tooth plates in these fishes represent the fusion of two members of a reduced tooth family. The condition of the tooth plates in C. milii is plesiomorphic for chimaeroids and is of evolutionary significance in that it provides further evidence to support a lyodont dentition in chimaeroid fishes similar to that found in other chondrichthyans. © 1994 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
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    Morphological and functional body reconstruction in a teleost of the genus Oreochromis (Cichlidae) (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 219 (1994), S. 1-6 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The process of morphological and functional regeneration was followed on a tilapid fish, a cross of Oreochromis aureus × Oreochromis niloticus, by observations on movements and the use of X-rays. A four-year-old adult fish that lost its tail as post larva, including ten vertebrae, was able to reconstruct a novel and shorter central skeleton, including a specially modified urostyle. The enlarged and strengthened pterygiophores and their junctions with the dorsal and anal spine formed a fast-holding base for the fins, the posterior part of which largely performed the functions of the missing caudal fin. Although the fish was much shorter than usual, this male behaved and functioned normally. © 1994 Wiley-Liss, Inc.
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    Ultrastructure of the paraphysis in Bufo bufo larvae (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 219 (1994), S. 7-13 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A study of the ultrastructure and function of the paraphysis in Bufo bufo larvae was carried out. The structure is a tubular-ramified gland made up of numerous tubules with monolayered epithelial walls surrounded by connective tissue and sinusoids. The epithelial cells secrete glycoprotein to contribute to production of the cephalorachidian fluid. The role of the paraphysis in the transport of fluids and electrolytes from the blood to the cephalorachidian fluid in regulation of ionic and osmotic homeostasis is discussed. © 1994 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052190103
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  • 41
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    Characteristics of the flagellar axoneme in Neuroptera, Coleoptera, and Strepsiptera (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 219 (1994), S. 15-20 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spermatozoa from representatives of the five insect orders in superorder Neuropteroidea were examined by electron microscopy following a new fixation method that includes tannic acid in the primary fixative but has uranyl acetate rather than osmium tetroxide as the secondary fixative. The sperm axoneme was found to be similar in the four orders Megaloptera, Raphidioptera, Neuroptera, and Coleoptera, and is characterized above all by its so-called intertubular material being divided into two portions, one located outside, but in contact with the doublet, and the other projecting from the accessory tubule and having a beak-like shape. These features have not been seen in insects from other orders and may be a synapomorphy for these neuropteroid orders. The accessory tubules in these four orders have 16 protofilaments. The shape of the accessory bodies adjacent to the mitochondrial derivatives is nearly the same in insects from the more primitive neuropteroid orders and in Coleoptera. The sperm tail of the examined strepsipteran deviates in several respects from that of other neuropteroids: the particle row in the wall of accessory tubules is incomplete, an intertubular material is missing, and the mitochondria contain no crystal. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052190104
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    Spiral cleavage and cell position contribute to the specification of the dorsoventral axis in the embryo of the archaeogastropod Haliotis tuberculata (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 219 (1994), S. 21-33 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the embryo of Haliotis tuberculata spiral cleavage induces size differences between the quadrants in the 4-cell embryo. These size differences, together with the formation of compact cell configurations, induce asymmetrical positions of equivalent cells in the 8- and 16-cell embryo. The asymmetries in size and position influence the final specification of the dorsoventral asymmetry in the 32-cell embryo, as well as formation of the mesentoblast. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    Eversible abdominal vesicles and some observations of the male reproductive system of the spoon wing lacewing Palmipenna (Neuroptera: Nemopteridae) (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 219 (1994), S. 47-58 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The anatomy and histology of the abdominal eversible vesicles and the male reproductive tract of the spoonwing lacewing Palmipenna (Neuroptera: Nemopteridae) have been examined. The eversible vesicles open as a pair of large bulbous sacs between tergites five and six, each folding into halves during retraction. They consist of highly pleated cuticle, beneath which are typical gland cells, each having a circular or oval end apparatus surrounded by closely packed microvilli. These communicate to the surface via cuticularized channels. In spite of considerable behavioral observations, male Palmipenna were never noted with everted vesicles. Even during mating trials, where females were presented to males in the field, the vesicles were never everted during the attempted copulation that ensued. Our observations indicate that mate attraction is mediated by the release of a female pheromone. The function of the eversible vesicles and their associated gland cells remains unknown, and their structure appears to be unique to the Nemopteridae. The reproductive tract is similar to that of other Neuroptera, consisting of a pair of five-lobed testes, a medium-to-large pair of seminal vesicles, and three pairs of accessory glands. The major accessory glands are surrounded by circular and longitudinal muscle, and are lined by an epithelium, the cells of which presumably secrete the amorphous rods of material always present in this pair of glands. The sperm in the seminal vesicles are elongate, with a pointed head and a 9 + 9 + 2 configuration in the flagellum. A single spermatophore, similar in shape to that described for other Neuroptera, was found occluding the bursa copulatrix of a teneral female. © 1994 Wiley-Liss, Inc.
    Additional Material: 24 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052190107
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  • 44
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    In vivo fluorescence imaging of the functional organization of trophotaenial placental cells of goodeid fishes (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 219 (1994), S. 35-46 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Embryos of viviparous goodeid fishes undergo a 10 to 150 × increase in dry weight during gestation. Maternal nutrients are transferred across a trophotaenial placenta comprised of the ovarian lumenal epithelium and the trophotaeniae of the embryo. Trophotaeniae are externalized projections of the embryonic hindgut. Epithelial cells of the ribbon trophotaenia (Ameca splendens) resemble intestinal absorptive cells of suckling mammals and endocytose macromolecules. They possess an apical brush border, endocytotic complex, endosomal-lysosomal system, and apical and basal clusters of mitochondria. Cells of the rosette trophotaenia (Goodea atripinnis) lack an endocytotic apparatus, have small lysosomes, two mitochondrial clusters, and transport small molecules. Organelle-specific fluorescent probes were employed to characterize the functional organization of the two types of trophotaenial cells. In A. splendens, Lucifer Yellow, a membrane-impermeable tracer of vesicular transport, first appears in peripheral vesicles (15-45 sec), then passes into elongated tubular endosomes (1-3 min) and later appears in large central vacuoles (10-15 min). These vacuoles accumulate Acridine Orange, a classical probe for lysosomes, and have been shown to contain lysosomal enzymes. Endosomelysosome fusion was observed. In both A. splendens and G. atripinnis, Rhodamine 123 fluorescence was localized in two clusters of fine spots that corresponded to mitochondria. 4′,6-diaminido-2-phenyl-indole (DAPI) staining of nuclei established the positional relationships of cell organelles with respect to the nuclei. 3,3′-dihexyloxacarbo-cyanine iodide (DiOC6) revealed the perinuclear distribution of the endoplasmic reticulum. In order to compare in vivo fluorescence of Lucifer Yellow with previous ultrastructural observations, we employed fluorescence photoconversion and electron microscopy. © 1994 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052190106
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  • 45
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    Ontogenesis and ultrastructure of seminal vesicles of the catfish, Clarias gariepinus (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 219 (1994), S. 59-71 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ontogenesis and structural characteristics of the seminal vesicles in Clarias gariepinus (sharptooth catfish) were studied by light and electron microscopy and are described in detail. The seminal vesicles, beginning as simple protrusions from the vas efferentia, becomes more complex with age. Their distal ends become fingerlike and the bases form palm-like extensions. Juvenile male organs do not reveal any signs of seminal vesicles although spermatogenic tissue is already well delineated. The developing gonads contain clusters of large cells, close to the sperm duct and cysts of the testis, from which seminal vesicles are formed. Secretory epithelium lines the tubules of the seminal vesicles and becomes columnar as the tissue matures. Electron micro-graphs of these epithelial cells reveal two types of cells: opaque cells and cells with very vacuolized cytoplasm. Dense pinocytotic vesicles are present between the membranes of neighbouring seminal tubules and apical cell membranes facing the lumen. Maturation and onset of secretion by the secretory cells is accompanied by morphological changes. Protruding cylindrical cells become shortened, modified to cuboidal, rounded cells that send tubular extensions into the lumen. In the final stage of differentiation, only connective tissue membranes supporting the tubule walls remain intact. At the points of contact between the testis, seminal vesicles, and sperm duct, the epithelia of these organs often become confluent. The distal parts of the seminal vesicles, rarely contain sperm; during spawning sperm accumulated in the proximal tubules of the vesicles. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052190108
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 219 (1994) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052190201
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  • 47
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    External morphology and abundance of antennal sensilla in australian gryllacrididae (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 11-18 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The long (49-93 mm) antennae of two species of Australian gryllacridids have high total numbers of sensilla consisting of five sensillar types. Ametrus sp. 7 has 22,300 (♀) and 26,250 (♂) sensilla; although the antennae of males are 33% longer than those of females, their sensillar density was 11% less. Bothriogryllacris pinguipes has 26,700 (♂) and 31,900 (♀) sensilla; antennae of females are 55% longer than those of males but sensillar density is 23% less. Aporous sensilla chaetica form 94.5 to 99.5% of all sensilla; they are presumably mechanoreceptors. Uniporous trichoid contact chemoreceptors range from 75-900 in number. Olfactory, multiporous, basiconic sensilla range from 22-440 and olfactory, coeloconic sensilla from 16-235. Two to five multiporous lenticular organs occur on all but female A. sp. 7. Differences in sensillar abundance between males and females are discussed as well as are the relationships between sensillar diversity on gryllacridid mouthparts and antennae. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    Immunofluorescent studies on titin and myosin in developing hearts of normal and cardiac mutant axolotls (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 19-32 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Homozygous recessive cardiac mutant gene c in the axolotl, Ambystoma mexicanum, results in a failure of the embryonic heart to initiate beating. Previous studies show that mutant axolotl hearts fail to form sarcomeric myofibrils even though hearts from their normal siblings exhibit organized myofibrils beginning at stage 34-35. In the present study, the proteins titin and myosin are studied using normal (+/+) axolotl embryonic hearts at stages 26-35. Additionally, titin is examined in normal (+/c) and cardiac mutant (c/c) embryonic axolotl hearts using immunofluorescent microscopy at stages 35-42. At tailbud stage-26, the ventromedially migrating sheets of precardiac mesoderm appear as two-cell-layers. Myosin shows periodic staining at the cell peripheries of the presumptive heart cells at this stage, whereas titin is not yet detectable by immunofluorescent microscopy. At preheartbeat stages 32-33, a myocardial tube begins to form around the endocardial tube. In some areas, periodic myosin staining is found to be separated from the titin staining; other areas in the heart at this stage show a co-localization of the two proteins. Both titin and myosin begin to incorporate into myofibrils at stage 35, when normal hearts initiate beating. Additionally, areas with amorphous staining for both proteins are observed at this stage. These observations indicate that titin and myosin accumulate independently at very early premyofibril stages; the two proteins then appear to associate closely just before assembly into myofibrils. Staining for titin in freshly frozen and paraffin-embedded tissues of normal embryonic hearts at stages 35, 39, and 41 reveals an increased organization of the protein into sarcomeres as development progresses. The mutant siblings, however, first show titin staining only limited to the peripheries of yolk platelets. Although substantial quantities of titin accumulate in mutant hearts at later stages of development (39 and 41), it does not become organized into myofibrils as in normal cells at these stages. © 1994 Wiley-Liss, Inc.
    Additional Material: 21 Ill.
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  • 49
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052220201
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  • 50
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    Quantitative design of the skeleton in bird hatchlings: Does tissue compartmentalization limit posthatching growth rates? (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 113-131 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Based on a detailed description of hatchling skeletons of the precocial buttonquail (Turnix suscitator) and the altricial budgerigar (Melopsittacus undulatus), this report presents the hypothesis that the rate of avian posthatching growth is limited by the quantitative design (i.e., relative volumes of cartilage, bone, and marrow) of the hatchling skeletons. A Jarge portion of bone in the skeletal elements and fast growth are hypothesized to be mutually exclusive. This hypothesis is tested by morphometric techniques and by statistical comparison of morphometric and growth data. All predictions are met by the data, and the design of hatchling skeletons is described as determined by a tradeoff between tissue composition of skeletal elements and maximum rates of posthatching growth. The precocial design shows large bony areas that supposedly resist mechanical stress of locomotion; however, the relatively small cartilaginous areas exclude high growth rates. The altricial design shows the reverse relationship with small bony areas and a lack of locomotion on the one side but large cartilaginous areas and fast posthatching growth on the other side. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    Kinematic analysis of jaw protrusion in orectolobiform sharks: A new mechanism for jaw protrusion in elasmobranchs (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 175-190 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Jaw protrusion is an important component of prey capture in fishes, although the mechanics of protrusion have thus far been studied largely in teleosts. Elasmobranchs are also able to protrude their jaws (Tricas and McCosker [1984] Proc. Cal. Acad. Sci. 43: 221-238; Tricas [1985] Mem. S. Calif. Acad. Sci. 8:81-91.; Frazzetta and Prange [1987] Copeia 4:979-993). Several related features of the feeding apparatus contribute to jaw protrusion in sharks. Labial cartilages form an extendible series attached dorsally to the anterolateral face of the palatoquadrate and ventrally to the anteroventral surface of Meckel's cartilage. The labial cartilage chain swings anterolaterally as the lower jaw is depressed, thrusting the labial margins forward to form a circular oral opening and displacing the jaw apparatus towards the food; this pattern is analogous to halecomorph and primitive actinopterygian fishes in which the maxilla swings forward (Lauder [1979] J. Zool. Lond. 187:543-578). The palatoquadrate and Meckel's cartilage also project anteriorly and represent the major contribution to protrusion. These movements occur simultaneously with enlargement of the oral cavity to generate suction. The wobbegong sharks (Orectolobidae) are specialized for jaw protrusion. The spotted wobbegong protrudes its jaw by 33% of its chondrocranial length using two different mechanical systems. In the first mechanism of jaw protrusion, the intermandibularis and interhyoideus muscles medially compress the lower jaw and hyomandibulae. Compression of the lower jaw results in a more acute symphyseal angle so that the anteroposterior alignment of the lower jaw increases due to the rotation of each lower jaw towards a saggital orientation. Distal compression of the hyomandibulae at their attachments to the jaws swings the jaws forward. The second mechanism involves rotation of the ceratohyal around a posterior process of the lower jaw, pushing the hyomandibulae anteroventrally, thereby pushing the jaw articulation ventrally and anteriorly to protrude the jaws. © 1994 Wiley-Liss, Inc.
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    Localization and distribution of gap junctions in normal and cardiomyopathic hamster heart (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 203-213 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gap junctions in mammalian heart function to provide low-resistance channels between adjacent cells for passage of ions and small molecules. It is clear that the almost unrestricted passage of ions between cells, ionic coupling, is required for coordinate and synchronous contraction. This knowledge of gap junction function has made it important to study their properties in normal and abnormal tissues. In the present study, we analyzed gap junction distribution in normal and cardiomyopathic heart tissue utilizing immunofluorescent and electron microscopy techniques. Frozen, unfixed sections of age-matched normal and cardiomyopathic cardiac tissues were immunofiuorescently stained using an antibody directed against a specific peptide sequence of the connexin-43 gap junction protein. These studies revealed a characteristic punctate staining pattern for the intercalated discs in normal tissues. Some of the intercalated discs in cardiomyopathic hearts appeared to stain normally; however, others stained diffusely. The pixel intensity distribution of the confocal images demonstrated a marked difference of up to 90% increase in the number of pixels in cardiomyopathic myocardium (CM), yet the pixel intensity of gap junctions had a decrease of approximately 60%. This suggests the possibility that connexin-43 is present in CM cells in significant quantity; however, it does not become localized on the membranes as in normal cells. Electron-microscopic findings corroborate these observations on CM cells by showing an irregular distribution of intercalated discs relatively smaller in size with abnormal orientation and distribution. © 1994 Wiley-Liss, Inc.
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052220301
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    Phylogenetic implications of structure of adult ovary and oogenesis in the penicillate diplopod, Eudigraphis nigricians (miyosi) (diplopoda: Myriapoda) (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 223-230 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe some significant structures of the adult ovary in a Japanese penicillate diplopod, Eudigraphis nigricans, with respect to phylogenetic implications. The ovary is a long, saclike organ lying between the alimentary canal and the ventral nerve cord from the fourth through the ninth body segment. The ovarian wall consists of a thin ovarian epithelium and a sparse muscle covering. There are two types of oogenetic sites: a single, mound-shaped germarium sitting on the center of the ventral ovarian epithelium, and ∼ 10 pairs of patchlike vitellarial areas metamerically arranged anterior and posterior to the germarium. The germarium consists of oogonia, early previtellogenic oocytes, and some somatic interstitial cells. In contrast, the vitellarial areas are composed of more advanced oocytes, follicle cells surrounding the oocytes, and some interstitial cells, but no oogonia. A few larger previtellogenic oocytes rise up from each vitellarial area into the ovarian lumen. Each of these oocytes is still connected with its own vitellarial area by a partial extension of its follicle. Vitellogenesis takes place in these oocytes rising in the ovarian lumen. The ripe primary oocytes leave their follicles to be transported forward into the oviducts. Some phylogenetic implications of the basic characteristics in ovarian structure and oogenesis of E. nigricans are discussed. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052220302
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    Morphology of shells from viable and nonviable eggs of the chinese alligator (Alligator sinensis) (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 103-110 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology of eggshells from hatched eggs of captive Chinese alligators (Alligator sinensis) was compared with that of shells from eggs with early embryonic death and with the morphology of eggshells from the American alligator (Alligator mississipiensisis). Pieces of shells were examined in the scanning electron microscope. Parameters examined included: numbers of open pores on the outer surfaces, total shell thickness, and thickness of the outer densely calcified and inner mammillary layers. Results indicate that shells from Chinese and American alligator eggs with early embryonic death have a thicker outer densely calcified layer than do shells from hatched eggs or full-term embryos. Also, eggshells from Chinese alligator eggs with dead embryos have fewer open pores on the outer surface than do shells from hatched eggs, as has been reported earlier for the American alligator (Wink et al., '90). © 1994 Wiley-Liss, Inc.
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    Development of craniofacial musculature in Monodelphis domestica (marsupialia, didelphidae) (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 149-173 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Development of craniofacial muscles of Monodelphis domestica (Marsupialia, Didelphidae) is described. In a period of 4-6 days all craniofacial muscles in M. domestica progress from myoblast condensation, to striated myofibers that are aligned in the direction of adult muscles and possess multiple, lateral nuclei. This process begins 1 to 2 days before birth and continues during the first few days after birth. Compared to other aspects of cranial development, muscle development in M. domestica is rapid. This rapid and more or less simultaneous emergence of craniofacial muscles differs from the previously described pattern of development of the cranial skeleton in marsupials, which displays a mosaic of acceleration and deceleration of regions and individual elements. Unlike the skeletal system, craniofacial muscles show no evidence of regional specialization during development. M. domestica resembles eutherian mammals in the relatively rapid and more or less simultaneous differentiation of all craniofacial muscles. It differs from eutherian taxa in that most stages of myogenesis occur postnatally, following the onset of function. The timing of the development of muscular and skeletal structures is compared and it is concluded that the relatively early development of muscle is not reflected by any particular acceleration of the differentiation or growth of skeletal structures. Finally, the difficulties in accounting for complex internal arrangements of muscles such as the tongue, given current models of myogenesis are summarized. © 1994 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
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    Ultrastructure of the ileum epithelium of Melipona quadrifasciata anthidioides (hymenoptera, apidae, meliponinae) (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 191-201 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Study of the epithelial morphology of a stingless bee ileum from the pyloric valve to the last portion of high absorptive cells shows that although the bee ileum is an anatomically undifferentiated tube, four types of epithelial cells along the tube (in addition to the valve cells) indicate physiological differentiation. The anterior end seems to be less active in reabsorption, while the posterior region contains cells with typical morphology of an ion pump and permits conclusions about the mechanisms of absorption in the posterior end of the intestine. © 1994 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052220206
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    Allometry of cetacean forelimb bones (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 215-221 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study examines the allometric scaling relationships of the cetacean humerus, radius, and ulna. Bone lengths and diameters were measured for 20 species of odontocete and three species of mysticete cetaceans, representing eight of the nine extant cetacean families. The scaling of individual bone proportions (bone length vs. cranio-caudal diameter, bone length vs. dorso-ventral diameter), and of individual bone dimensions against estimated body mass, are compared to models of geometric and elastic similarity. The geometric similarity model describes the scaling relationship of bone length vs. cranio-caudal diameter and body mass vs. cranio-caudal diameter for the humerus only; geometric similarity also describes the scaling relationship of body mass vs. bone length for all three bones. None of the scaling relationships fits the elastic similarity model. The scaling relationships of bone length vs. dorso-ventral diameter for all three bones, and bone length vs. cranio-caudal diameter for the radius and ulna, exhibit negative allometry, indicating that large bones are less robust than small bones. Negative allometry of structural support elements has not been previously described for terrestrial mammals or plants. The high relative swimming speeds of small delphinids may generate sufficient stresses to require more robust bones relative to those of larger whales. © 1994 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052220208
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    Spermatogenesis in the urodele Amhystoma dumerilii (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 287-299 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The male reproductive cycle of this paedomorphic species that occurs only in Lake Pátzcuaro, Michoacán, México, was investigated by documenting changes in germinal cells during the spermatogenic cycle. Cysts of germ cells divide synchronously to complete spermatogenesis during September through December, with the proportion of evacuated cysts or cysts containing spermatozoa increasing during this period. The chromatin changes during prophase I of meiosis reveal the usual leptotene, zygotene, pachytene, and diplotene stages. A basal body at the caudal end of the spermatozoan head connects to the flagellum. After spermiation, empty cysts contain a granular substance. Spermatogenesis in this species follows an annual cycle like other north temperate salamanders, rather than the continuous spermatogenesis of some tropical salamanders. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052220306
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    Effects of anisosmotic conditions on the cytoskeletal architecture of cultured PC12 cells (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 269-286 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: PC12 cells show a classical volume regulatory process when submitted to hypo-osmotic conditions. The present study examined the effects of such osmotic shock on the structural organization of different cytoskeletal elements. Results were obtained by use of different light and electron microscopy techniques combined with immunostaining methods. It appeared that the osmotically induced changes in cell volume were concomitant with important modifications in the organization of the microfilament network. Microfilaments concentrated in the perinuclear area, leaving only radial extensions of poorly organized structures in the cytoplasm. The latter were the only actin structures immunologically stained in the cytoplasm and seemed to anchor to the plasma membrane. Measurements of the fluorescence intensity of PC12 cells treated with FITC-labeled phalloidin indicated a progressive depolymerization, followed by a repolymerization of F-actin. This occurs in parallel with microfilament reorganization and volume regulatory processes. The appearance of microfilament reorganization was a function of both the incubation period and the amplitude of the osmolarity changes. During the first minutes of osmotic shock, a decrease was observed in the density and length of microvilli, which normally cover the PC12 cell surfaces, suggesting an early reorganization of the underlying microfilament network. Microtubules and intermediate filament networks were not affected by the hypo-osmotic conditions. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052220305
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    Olfactory organ of acipenseriformes and comparison with other actinopterygians: Patterns of diversity (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 241-267 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The position and structure of the olfactory organ and its openings vary among actinopterygians. The anterior nasal opening is a simple perforation in the skin in many extant actinopterygians (e.g., acipenseriforms, lepisosteids, and primitive Recent teleosts) and represents the primitive condition. Polypterids and Amia each exhibit a derived condition, in which the anterior nasal opening extends into a tube. The olfactory organ is relatively far away from the anterior end of the elongate rostrum in acipenseriforms, whereas the olfactory organs are closer to the anterior end of the snout in extant actinopterygians (e.g., polypterids, lepisosteids, and amiids). In adults, olfactory organs are cuplike structures in most actinopterygians, but these organs are tubelike in polypterids. Among extant actinopterygians, a nasal diverticulum is present only in polypterids. Teleosts have accessory nasal sacs, but chondrosteans, polypterids, lepisosteids, and amiids lack them.The olfactory rosette is formed by primary folds or lamellae that may be placed anterior, lateral, posterior, and/or medial to the axis of the organ. Large acipenserids have 20-32 lamellae, polyodontids have 13-18 lamellae, lepisosteids have 8-10 lamellae, and Amia may have over 100. In teleosts, the number of lamellae varies from none or a few to over 200. Secondary lamellae are present in acipenseriforms, lepisosteids, and some advanced teleosts; secondary lamellae are interpreted as independently acquired in these lineages. Secondary lamellae are absent in Amia and primitive teleosts such as Elops and Hiodon. Tertiary lamellae are present in Acipenser oxyrhynchus. The arrangement of the primary lamellae in relation to the axis of the organ results in at least 11 patterns of the olfactory rosette in actinopterygians. Lamellae that are enclosed in a tubelike sac and that have an anteromedial diverticulum are specializations of polypterids. Primary lamellae anterior, lateral, and posterior to an elongate axis are characteristic of lepisosteids. The presence of primary lamellae lateral, medial, and posterior to an elongate olfactory axis is a synapomorphy of Halecomorpha (Amia plus teleosts). The absence of secondary lamellae is a synapomorphy of Halecomorpha. © 1994 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052220304
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    Negative growth control of mitotically active imaginal cells (histoblasts) of the abdominal epidermis during metamorphosis of the houseflyWe dedicate this paper to the memory of our graduate school mentor, Professor P. Govindan, Annamalai University, Tamil Nadu, India. (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 301-307 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: On the ventral side of each pupal abdominal segment of the housefly, there is a pair of histoblast nests, each containing about 600 diploid cells. These cells, during adult development, divide, replace intervening polytene larval epidermal cells (LEC), and form both the median sternite and the surrounding pleura of the adult segment. Since the histoblast nests and the LEC form a contiguous layer, we examined the role of these two types of cells in regulating the mitotic potential of the histoblasts during development of the median sternite. Two experimental approaches were used: deletion of one of the nests by thermocautery; and by disturbance of the continuity of the monolayered epidermis by thermocautery of, or topical application of heptanol on, the midventral LEC. Ablation of one of the contralateral nests resulted in a mirror image duplication of the hemisternite and pleura by the surviving nest. Disturbance of the continuity of the LEC produced mirror image duplication of the hemisternal pattern by each of the contralateral nests. From these results, we propose that the contralateral ventral nests mutually downregulate their mitotic potential by secreting regulatory factor(s) to produce the normal median sternite pattern and surrounding pleura. We also suggest that these chemicals act in a paracrine fashion, possibly through gap junctions in the LEC. © 1994 Wiley-Liss, Inc.
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    Locomotor analysis of surface propulsion by three species of reduced-limbed fossorial lizards (Lerista: Scincidae) from western australia (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 309-326 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The relatively large, but superficially similar, Lerista macropisthopus, L. connivens, and L. lineopunctulata differ in bodily elongation and limb reduction, inhabit sandy areas, and move under sand. Visual analysis and computer-generated excursion and curvature graphs show that each species moves differently on smooth and rough surfaces, on surfaces with and without nails, and in channels.The reduced-limbed quadruped, Lerista macropisthopus walks frequently, using its four clawed limbs, whenever traction is available. Its undulating body curves uniformly but never generates slide-pushing curves. The biped L. connivens walks with its hindlimbs, although less frequently, and/or oscillates its tail in propelling its relatively stiff, short body. The biped L. lineopunctulata rarely uses its hindlimbs but always undulates body and. tail. It can use single nails in cam-follower progression. L. macropisthopus and L. connivens walk well in channels with rough bottoms, but only L lineopunctulata uses tunnel concertina to travel in channels with smooth bottoms.Friction of body surfaces dragged and of those transmitting propulsive forces is critical to these lizards and explains the division of movement into slow and rapid progression rates. Animals that have clawed limbs, no matter how reduced, use them. Body and tail generally are used differently. The tail may be flipped anteriorly to facilitate concertina. In nail arrays, travel is by simple, never by lateral, undulation. Apparently distinct motor coordination patterns are associated with differences in morphology, habit, and habitat. © 1994 Wiley-Liss, Inc.
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    Detection of sugar residues in lizard tooth germs (Liolaemus gravenhorsti) using lectin histochemistry (1994)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 222 (1994), S. 327-335 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The appearance, cellular distribution, and changes of sugar residues during tooth development in adults of the polyphyodont, Liolaemus gravenhorsti, were investigated by using horseradish-peroxidase-conjugate lectins (lectin-HRP). With Con A (Canavalia ensiformis), the ameloblasts (late bell stage) show granular supranuclear positivity and also at the Golgi zone and on their tomes process. Reactivity also appears at the apical surface of the odontoblasts and odontoblastic process. With WGA (Triticum vulgaris), the tooth germs (late bell stage) show cytoplasmatic granular positivity in the ameloblast cells, Golgi regions, and in a lesser extent of the cytoplasm. Also, the apical surface and the odontoblastic process react. WGA reaction is depressed following sialidase treatment.The significance in tooth germs of α-D-mannose, α-D-glucose as well as β-D-N-acetylglucosamine and sialic acid is difficult to ascertain. These oligosaccharides may have some significance in odontogenesis. In fact, Con A-HRP- and WGA-HRP-binding components in ameloblasts and odontoblasts may be functionally related to molecules that are thought to contribute to odontogenesis in lizards. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052220309
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    Occurrence of fibers and their association with talin in the cleavage furrows of PtK2 cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 26-40 
    Details
    ISSN: 0886-1544
    Keywords: cleavage furrows ; cytokinesis ; actin ; phalloidin ; myosin ; filamin ; talin ; attachment plaques ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: PtK2 cells of exceptionally large size were microinjected with fluorescently labeled probes for actin, myosin, filamin, and talin in order to follow the assembly of the contractile proteins into the cleavage furrows. Whereas in cells of normal size, there is usually a diffuse pattern of localization of proteins in the cleavage furrow, in these large, flat cells the labeled proteins localized in fibers in the cleavage furrow. Often, the fibers were striated in a pattern comparable to that measured in the stress fibers of the same cell type. The presence of talin in discrete plaques along fibers in the cleavage furrows of the large cells suggests a further similarity between cleavage furrow and stress fiber structure. The presence of filamin in the cleavage furrows also suggests the possibility of an overlapping mechanism in addition to that of a talin mediated mechanism for the attachment of actin filaments to the cell surfaces in the cleavage furrow. A model is presented that emphasizes the interrelationships between stress fibers, myofibrils, and cleavage furrows. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970270104
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    Role of MAPs and motors in the bundling and shimmering of native microtubules from insect ovarioles (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 69-78 
    Details
    ISSN: 0886-1544
    Keywords: kinesin ; dynein ; MAP-motor interactions ; microtubule arrays ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Bundles of native microtubules isolated from the ovarioles of hemipteran insects are seen to shimmer when observed using dark-field microscopy. This novel form of microtubule motility becomes even more obvious when the isolated bundles are detergent-extracted and reactivated. We have studied the nucleotide-specificity and the drug-sensitivity of microtubule shimmering in order to obtain information regarding the nature of the motor protein responsible, and to compare its properties with those of previously characterised microtubule motors. The involvement of structural MAPs in the shimmering and in maintenance of microtubule bundles in this system has also been investigated. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970270108
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    Role of microtubules in random cell migration: Stabilization of cell polarity (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 88-96 
    Details
    ISSN: 0886-1544
    Keywords: cell movement ; speed ; persistence time ; colcemid ; alveolar macrophage ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The role of microtubules in random cell migration was investigated using time-lapse videomicroscopy to record in vitro the shape and motile behavior of guinea pig alveolar macrophages before and after disrupting microtubules with colcemid. Cell migration was quantified in terms of directional persistence time and speed. Motility was also correlated with morphological polarity: cells having a single lamellipodal region (monopolar cells) migrated, whereas those lacking a lamellipod (apolar cells) or with opposing lamellipodal regions (bipolar cells) did not migrate. Within 2 hours, colcemid caused a shift in polarity from 80% monopolar cells to 40% monopolar and 40% bipolar cells and a corresponding decrease from 80% to 40% in the fraction of migrating cells. Mean persistence time and speed decreased only slightly (approximately 20%) for those cells (still monopolar) which continued to migrate in the presence of colcemid. Persistence time and speed actually increased for many individual cells, indicating that random migration did not require intact microtubules. We conclude that colcemid treatment destabilizes monopolarity, leading to the gradual loss of monopolarity and consequent inhibition of migration. While a cell remains monopolar, it will continue to migrate even in the absence of intact microtubules, but microtubules are required for the long-term maintenance of cellular monopolarity and, thus, for continued motility. © 1994 Wiley-Liss, Inc.
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    Two-step mechanism for actin polymerization in human erythroleukemia cells induced by phorbol ester (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 327-336 
    Details
    ISSN: 0886-1544
    Keywords: HEL cells ; cell spreading ; fibronectin ; diacyl glycerol ; phorbol myristate acetate ; protein kinase C ; staurosporine ; thymosin beta four ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Human erythroleukemia (HEL) cells grow in suspension, but after treatment with nM PMA the cells adhere and spread on glass or fibronectin [Jarvinen et al., 1987: Eur. J. Cell Biol. 44:238-246]. We observed an early (20-30 min) stage of spreading in which F-actin was organized into peripheral arcs near the spreading margin and vinculin was localised to the cell's periphery at the ends of these arcs. By 1 h the cells were well spread with straight actin bundles many of which ended at more central sites terminating on patches containing vinculin and talin; thus the cells assemble typical stress fibers but do not appear to polarize. The cells also spread on RGD polymer. DiC8 (1,2-dioctanoyl-sn-glycerol, C8:0, Sigma Chemical Co., St. Louis, MO) induced spreading but only if DAG kinase inhibitor and A-23187 were also present; in their absence cells adhered but did not spread. Spreading was ∼85% inhibited by 100 nM staurosporine. PKC-β was shown to be present in the cells by immunoblotting. In cells spread for 1 h with PMA, F-actin increased to 180% of control levels as measured by RP binding and the actin sequestering complex of G-actin-thymosin β4 decreased significantly.To determine whether the F-actin increase required adhesion, we inhibited cell attachment to the substratum by adding RGDS, by coating glass surfaces with hemoglobin, or by a combined treatment. Under these conditions PMA-treated suspended cells still increased their F-actin to 126-137% of controls, a significant increase over control levels. Staurosporine inhibited F-actin increases under all the conditions studied.Permeabilized cell suspensions, incubated with rhodamine labelled G-actin, incorporated the labelled actin along cell membranes at a low level. A few minutes preincubation with either diC8 plus DAG kinase inhibitor or with PMA strongly increased the incorporation. This increased incorporation was reduced to below control levels by either staurosporine (100 nM) or cytochalasin D (1 μM).We conclude that both suspended and spreading HEL cells can be stimulated to polymerize actin by a mechanism dependent on PKC or a PKC-like molecule. In suspended cells, the polymerization occurs along the membrane. When cells spread, F-actin increased to a significantly greater extent. This second step could involve additional polymerization, perhaps at the observed adhesion sites, decreased turnover of the actin bundles, or a combined effect of both mechanisms. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970270405
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    Are microtubules essential for the secretory process in rat parotid gland? (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 34-44 
    Details
    ISSN: 0886-1544
    Keywords: exocrine gland ; protein secretion ; microtubule-disrupting drugs ; immunofluorescence microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The role of microtubules in the exocrine secretory process is not yet well established, and their disruption by anti-microtubule drugs leads to variable effects on intracellular transit and protein secretion. We investigated the involvement of microtubules in the regulated secretory process of rat parotid glands using microscopic techniques and pulse-chase experiments. We showed that 10 μM colchicine or nocodazole destroys the microtubule network in parotid acinar cells but only weakly reduces the release of newly synthesized proteins. The half-effect was obtained with 0.22 μM colchicine. Moreover, this small reduction was found to be independent of the nature of the drug (colchicine, colcemid, or nocodazole) and of the nature of the stimulation (β-adrenergic or cholinergic pathways). Using nocodazole, we have been able to determine that the steps affected by the drug are very early events in the secretory pathway. Finally, we showed by kinetic analysis that microtubule disruption slows protein release only moderately but does not reduce the total amount of secreted protein. We conclude from this study that microtubule integrity is not essential for protein secretion in rat parotid gland. © 1994 Wiley-Liss, Inc.
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    Differences in the effect of Ca2+ on isolated microtubules from cod and cow brain (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 59-68 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; paracrystal ; coiled ribbons ; microtubule-associated proteins ; assembly ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Isolated microtubules from cod and cow brains were compared with respect to their response to calcium ions. The effect of Ca2+ on cod microtubules was found to be temperature dependent. In contrast to cow microtubules, cod microtubules assembled at 18°C. At this temperature the assembly was inhibited by Ca2+ concentrations of 2 mM and higher. This was also found for cow microtubules at 37°C. However, at 30°C there was no effect of 2 mM Ca2+ of the amount of assembly or disassembly of cod microtubules consisting of only tubulin or of tubulin and microtubule-associated proteins (MAPs). The morphology was affected though, since some coiled ribbons formed from tubulin and MAPs. The calcium-binding calmodulin did not alter the effect of calcium on cod microtubules markedly. At higher Ca2+ concentrations (〉4 mM), coiled ribbons were formed from cod tubulin and MAPs, but mainly amorphous aggregates and very few coiled ribbons were formed from cod tubulin alone, indicating that the Ca2+ effect is modulated by cod MAPs. The modulatory effect of cod MAPs was however not species specific, since both cod and cow MAPs had the same effect on cod microtubules, in spite of a different protein composition. A MAP-dependent effect of Ca2+ was also found for cow microtubule proteins. The assembly of pure cow tubulin, as well as that of cow tubulin and MAPs, was inhibited by 2 mM Ca2+. In the presence of 10 and 20 mM Ca2+, pure cow tubulin formed amorphous aggregates, rings, and even paracrystals, while the assembly of cow tubulin and MAPs was inhibited. Our results suggest therefore that the effect of Ca2+ can be moderated by MAPs, but depends on intrinsic properties of the different tubulins. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970280106
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    Movement of Myzostomum spermatozoa: Calcium ion regulation of swimming direction (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 135-142 
    Details
    ISSN: 0886-1544
    Keywords: bidirectional swimming ; flagellar movement ; helical bends ; 9+0 axoneme ; planar bends ; viscosity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spermatozoa of the small myzostomid worm Myzostomum cirriferum usually swim with the flagellum foremost but occasionally stop and then swim with the head foremost. The spermatozoa have axoneme of the 9+0 type; thus each lacks the central pair microtubules. The flagellum emerges in the anterior end of the cell body and attaches to it with junctions. To understand the mechanism regulating the swimming direction of the spermatozoa, we recorded the sperm and their flagellar movements using a video camera with a high-speed shutter. The effects of calcium and viscosity on these movements were also examined.The cell body with the flagellum attached to it formed a curved plate during beating, while the free portion of the flagellum beats with small helical bends. Motive force to propel a spermatozoon was mainly due to the bends in the cell body. The spermatozoa reversed the direction of their swimming as a result of a change in the direction of bend propagation. The direction of bend propagation was regulated by calcium; the bends in the cell body propagated from the end of the head toward the free portion of the flagellum at low concentrations of Ca2+, whereas the direction of bend propagation was reversed at high concentrations of this ion. High viscosity of the medium stimulated a change in the direction of bend propagation. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970280205
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    Role of tropomyosin, α-actinin, and actin binding protein 280 in stabilizing triton insoluble f-actin in basal and chemotactic factor activated neutrophils (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 155-164 
    Details
    ISSN: 0886-1544
    Keywords: microfilamentous cytoskeleton ; actin binding proteins ; formyl peptides ; ionic extraction ; immunoblots ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: F-actin is a major component of the neutrophil (PMN) cytoskeleton. In basal PMNs, F-actin exists in two structurally and functionally distinct pools: Triton insoluble F-actin (TIF)-cold insensitive, not depolymerizable by dilution, and distributed in pseudopods and submembranous locations; and Triton soluble F-actin (TSF)-unstable in cold, diffusely distributed, and gelsolin enriched. The element(s) conferring these unique properties to the Triton insoluble F-actin pool are unknown, but logically include distinct actin regulatory proteins. To study the morphologic and functional determinants of the Triton insoluble F-actin pool, the distribution and quantity of three candidate regulatory proteins, α-actinin, tropomyosin (TM), and actin binding protein (ABP-280), were compared in F-actin (Triton insoluble and Triton soluble) and G-actin pools isolated from basal and chemotactic factor activated human PMNs in suspension, using immunoblots and ionic extraction. F-actin content was measured by NBDphallacidin binding and gel scans. The results show that: (1) α-actinin, actin binding protein 280, and tropomyosin are localized to TIF and excluded from TSF; (2) TM, α-actinin, and ABP 280 are required to stabilize fractions of Triton insoluble F-actin in PMNs; and (3) chemotactic factor activation results in release of a fraction of TM from the Triton insoluble F-actin pool in temporal association with F-actin polymerization in the Triton insoluble F-actin pool. Shifts in ABP 280 or α-actinin do not occur. The results suggest that TM, α-actinin, and ABP 280 provide structure to TIF and that TM release from TIF is involved in chemotactic factor induced actin polymerization in PMNs. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970280207
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    Characterization of keratin densities in mitotic wish cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 165-178 
    Details
    ISSN: 0886-1544
    Keywords: WISH ; Keratin ; 3-D reconstruction ; mitosis ; intermediate filaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Three dimensional (3-D) reconstruction of four mitotic WISH cells from ultrathin sections gave an informative representation of the spatial distribution of keratin densities in these cells. The correspondence between the densities as studied by transmission electron microscopy (TEM) and the Keratin bodies initially revealed by immunoflourescent colabeling of cultures, was confirmed by immunoelectron-microscopy. The smaller, and sometimes more elongated densities, were relatively abundant just beneath the subplasmalemmal microfilament band; and at certain levels of the mitotic cell they were observed to be connected to neighboring densities by intact intermediate filaments (IFs). The larger and more spherical densities appeared to be somewhat more discrete and randomly distributed. Other observed associations of the keratin densities included the telophase contractile ring of microfilaments, chromosomes, the reformed telophase nucleus, and desmosomal junctions with neighboring interphase cells. Cytochalasin D (CD) treatment of cells displaced the peripheral keratin densities toward the cell membrane. The density volume constituted 0.52% to 1.57% of the total cell volume, and the proportional density size was decreased in the cells that had progressed into anaphase and telophase. The observed formation and subsequent dissolution of keratin densities during mitosis may represent a dynamic mechanism of restructuring the keratin cytoskeleton in an unpolymerized form in order to allow for rapid reformation of interphase cell junctions. The physical associations observed between intact IFs and the keratin densities may provide support at certain depths of the mitotic cell, and the juxtaposition of densities with nuclear components suggests a possible source of and role for keratin IFs during nuclear events. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970280208
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    Control of flagellar bending: A new agenda based on dynein diversity (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 199-204 
    Details
    ISSN: 0886-1544
    Keywords: axoneme ; cilia ; flagella ; microtubule ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Observations that were interpreted to provide evidence for equivalent functions of all axonemal dyneins should be reinterpreted, and models based on this assumption should be abandoned. In the future, attempts to understand the mechanisms for flagellar bending, oscillation, and bend propagation should start from the assumption that each type of axonemal dynein may have a specific function. At least three distinct functions can now be identified: bend initiation, maintenance of the angle of propagating bends, and generation of power to overcome viscous resistances. Only the last of these three functions is an outer arm dynein function. © 1994 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970280303
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    Cloning and sequencing of cDNAs encoding the actin cross-liking protein transgelin defines a new family of actin-associated proteins (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 243-255 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; actin binding ; transgelin sequence ; gelation ; gene family ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have used degenerate oligonucleotides, derived from the amino acid sequence of transgelin peptides [Shapland et al., 1993: J. Cell Biol. 121:1065-1073], to isolate and sequence overlapping cDNA clones encoding this actin gelling protein. Primers with 5′ restriction enzyme sites directed against the N and C terminal amino acids present in these clones were then used to amplify and clone the entire transgelin coding region from reverse transcribed rat small intestine cDNA (RT-PCR). These studies have shown that transgelin is the product of a single gene which is conserved between yeast, Drosophila, molluscs, and humans. Transgelin is expressed as a single message that is regulated at the level of transcription in SV40 transformed 3T3 cells. Our data have shown that transgelin and several other proteins of unknown function, SM22α [Pearlstone et al., 1987: J. Biol. Chem. 262:5985-5991], mouse p27 [Almendral et al., 1989: Exp. Cell Res. 181:518-530], and human WS3-10 [Thweatt et al., 1992: Biochem. Biophys. Res. Commun. 187:1-7], share extensive homology. More limited regions of homology shared between transgelin and other proteins such as rat NP25 (unpublished), chicken calponins α and β [Takahashi and Nadal-Ginard, 1991: J. Biol. Chem. 266:13284-13288], and Drosophila mp20 [Ayme-Southgate et al., 1989: J. Cell Biol. 108:521-531] suggest that all of these proteins may be classified as members of a new transgelin multigene family. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970280307
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    Signal transduction and calcium: A suggested role for the cytoskeleton in inositol 1,4,5-trisphosphate action (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 279-284 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280402
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    Coordinated expression of five tropomyosin isoforms and β-actin in astrocytes treated with dibutyryl cAMP and cytochalasin D (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 303-316 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; cell culture ; gene expression ; Northern blot ; serum-induction ; rat ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytochalasin D and dBcAMP cause cultured astrocytes to change from flat cells to retrated process-bearing cells. F-actin was present throughout cells stimulated with dBcAMP for 16 h, whereas cytochalasin D caused F-actin to form massive aggregates at the tips of the cell processes. The two drugs differently regulated the expression of both β-actin and tropomyosin genes in astrocytes cultured in the presence or absence of serum: dBcAMP caused down-regulation and cytochalasin D caused up-regulation. Northern blot analyses indicated that: (1) serum deprivation halved the concentration of all tropomyosin transcripts (TM-1, TM-2, TM-4, TMBr-1, TMBr-2). Serum induced TM-4 via transcriptional activation, independent of protein synthesis, (2) dBcAMP induced down-regulation of β-actin (-50%) and tropomyosin transcripts (-35 to 52%) even in the presence of serum. The concentration of profilin mRNA decreased in dBcAMP-reactive astrocytes (-46%). The decrease in β-actin mRNA concentration was not blocked by cycloheximide, whereas down-regulation of tropomyosin transcripts was completely reversed when protein synthesis was inhibited, and (3) cytochalasin D induced an increase in the concentration of tropomyosin transcripts (+ 69 to 185%) which was cumulative with serum stimulation. Cytochalasin D induction of both β-actin and TM-4 operated through transcriptional activation, independent of protein synthesis.The production of all tropomyosin transcripts examined here were strictly coordinated with β-actin expression in serum-, dBcAMP- and cytochalasin D-treated astrocytes. This indicates that the differential expression of tropomyosin isoforms occurring during astrocyte maturation is due to more complex regulation than that involved in serum- or cAMP-stimulated astrocytes. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970280404
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    Metachronal activity of cultured mucociliary epithelium under normal and stimulated conditions (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 333-345 
    Details
    ISSN: 0886-1544
    Keywords: ciliary beat frequency ; metachronal wave ; ciliary coupling ; extracellular ATP ; acetylcholine ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the present work we measured in real time the metachronism and degree of correlation between beating cilia from cultured mucociliary epithelium. The method is based on simultaneous measurement of ciliary beat frequency, phase shifts, and correlation factors in two directions: parallel and perpendicular to the effective stroke direction (ESD). From the phase shifts the lengths of wave components, and consequently the metachronal wavelength and direction, were evaluated.On active ciliary areas of cultured frog esophagus under normal conditions, a relatively high degree of correlation is observed, but cilia are more correlated in direction parallel to ESD which is also the direction of the mucus propulsion. The length of the wave component parallel to ESD is more than twice as large as that of the perpendicular component. The metachronal wavelength was found to be in the range of 5-9 μm, and the direction of the wave propagation was in the range of 90°-125° clockwise to the ESD.When ciliary beat frequency was rapidly increased by extracellular ATP or acetylcholine, only minor effects were observed on the degree of correlation between beating cilia. The length of the wave component parallel to ESD showed the most dramatic effect increasing up to tenfold. The perpendicular to ESD component was not affected by the stimulation. Consequently, the metachronism became more laeoplectic with the angle between the ESD and the wave directions decreasing by 10°-30°, and the metachronal wavelength remained unaltered. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970280407
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    Assembly and bundling of marginal band microtubule protein: Role of tau (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 57-71 
    Details
    ISSN: 0886-1544
    Keywords: microtubule bundling ; cytoskeleton ; tau ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubule protein extracted from dogfish erythrocyte cytoskeletons by disassembly of marginal bands at low temperature formed linear microtubule (MT) bundles upon reassembly at 22°C. The bundles, which were readily visible by video-enhanced phase contrast or DIC microscopy, increased in length and thickness with time. At steady state after 1 hour, most bundles were 6-11 μm in length and 2-5 MTs in thickness. No inter-MT cross-bridges were visible by negative staining. The bundles exhibited mechanical stability in flow as well as flexibility, in this respect resembling native marginal bands. As analyzed by SDS-PAGE and immunoblotting, our standard extraction conditions yielded MT protein preparations and bundles containing tau protein but not high molecular weight MAPs such as MAP-2 or syncolin. In addition, late fractions of MT protein obtained by gel filtration were devoid of high molecular weight proteins but still produced MT bundles. The marginal band tau was salt-extractable and heat-stable, bound antibodies to mammalian brain tau, and formed aggregates upon desalting. Antibodies to tau blocked MT assembly, but both assembly and bundling occurred in the presence of antibodies to actin or syncolin. The MTs were “unbundled” by subtilisin or by high salt (0.5-1 M KCl or NaCl), consistent with tau involvement in bundling. High salt extracts retained bundling activity, and salt-induced unbundling was reversible with desalting. However, reversibility was observed only after salt-induced MT disassembly had occurred. Reconstitution experiments showed that addition of marginal band tau to preassembled MTs did not produce bundles, whereas tau presence during MT reassembly did yield bundles. Thus, in this system, tau appears to play a role in both MT assembly and bundling, serving in the latter function as a coassembly factor. © 1994 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970290106
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    Fluorescence studies of spectrin and its subunits (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 72-81 
    Details
    ISSN: 0886-1544
    Keywords: spectrin ; intrinsic fluorescence ; spectrin elasticity ; fluorescence quenching ; spectrin α chain ; spectrin β chain ; membrane skeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To better understand the solution structure of spectrin, the environments of its tryptophan residues have been examined by fluorescence spectroscopy. The spectra and the extent of quenching by several quenching agents have been determined for intact spectrin and its α and β subunits. The arsenal of quenchers used in the study represented both hydrophilic and hydrophobic species including anionic, cationic and neutral compounds. Effects on spectrin fluorescence of ethanol and ionic strength, which extend and/or rigidify spectrin, and of glycerol, which is commonly used in electron microscopy of the protein, have also been assessed in the presence and absence of quenchers. Most of the tryptophans of spectrin are either internally quenched or are sequestered, hindering the approach of hydrophilic quenching agents. Both the spectral shape and the extent of quenching by acrylamide indicate that some tryptophans of the β subunit are slightly more exposed in the isolated chain than in the dimer. Similar effects on spectra and on quenching of the intact dimer and of the isolated β chain are seen when the ionic strength is reduced. Ethanol and glycerol reduce spectrin tryptophan accessibility to 2-p-toluidinyl napthalene-6-sulfonic acid (TNS). It therefore appears that low ionic strength, α-β association and neutral solute (or lowered dielectric constant) all induce a similar, but modest conformational change in the domain structure. The extent of TNS binding is not increased by lowering the ionic strength, suggesting that the expansion and/or stiffening of the molecule in low electrolyte solutions does not involve exposure of significant numbers of hydrophobic sites. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970290107
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    Effects of 6-dimethylaminopurine on the length of the cell cycle and on the state of phosphorylation of putative intermediate filament proteins in sea urchin embryos (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 131-140 
    Details
    ISSN: 0886-1544
    Keywords: intermediate filaments ; phosphorylation ; sea urchin embryos ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of 6-dimethylaminopurine (6-DMAP) on the length of the cell cycle and on the state of phosphorylation of a putative intermediate filament protein, p117, have been studied in sea urchin embryos. Embryos were transferred into sea water containing 600 μM 6-DMAP at 0.5, 2 or 5 min after insemination, and incubated for 30 or 90 min. The effects of 6-DMAP on cell cycle length were studied by determining the time required for completion of mitosis upon return of the embryos in normal sea water. In all instances, except for the embryos transferred 0.5 min after insemination (AI) and incubated for 30 min, the duration of the M phase was shortened compared to controls, being faster in the embryos incubated for 90 minutes compared to the 30 min incubation period. However, embryos transferred 0.5 min AI have a longer M-phase than those transferred 2 minutes or later after fertilization, suggesting that between 0.5 and 2 min after fertilization, critical phosphorylating events occur which affect the commitment of the cells to enter M-phase.To study the pattern of p117 phosphorylation during the cell cycle, the eggs were transferred 2 minutes after fertilization in presence of 600 μM 6-DMAP and with 200 μCi/ml of 32P-orthophosphate. Analyses of 32P-labelled proteins after exposure of SDS-PAGE gels and their corresponding blots suggested that phosphorylation of p117 greatly increases at the time of pronuclear fusion, and then declines slightly at prophase-metaphase. This decrease is markedly enhanced when the cells are treated with 6-DMAP during metaphase in order to induce a premature breakdown of the mitotic apparatus. A causal link is suggested between the level of phosphorylation of p117 and its state of assembly. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970290205
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290301
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    Substructure of cytoplasmic dense bodies and changes in distribution of desmin and α-actinin in developing smooth muscle cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 204-214 
    Details
    ISSN: 0886-1544
    Keywords: intermediate filaments ; cytoskeleton ; filament attachment sites ; immunogold labeling ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The substructure of assembling cytoplasmic dense bodies (CDBs) and changes in the distribution of desmin and α-actinin during development of smooth muscle were studied in gizzard samples from 10- and 16-day embryos and from 1- and 7-day post-hatch chickens. CDBs in these cells lack the density of CDBs in mature or adult smooth muscle cells and, thus, allow observations of the changes inside CDBs. The random filament orientation seen in younger embryonic cells is first modified to include relatively small patches of IFs that are somewhat straighter and are approaching a side-by-side arrangement. As development proceeds, the IFs in these arrays become straighter, are parallel over longer lengths of the IFs and later acquire the density characteristic of mature CDBs. Anti-desmin labeling in embryonic 10- and 16-day cells showed that desmin intermediate filaments (IFs) were located in the myofilament compartment but were concentrated in or near assembling CDBs. Anti-desmin labeling shifted to the perimeter of CDBs after hatching. Cross sections, longitudinal sections, and stereo pairs all show that IF profiles are present inside unlabeled assembling CDBs. Anti-α-actinin labeling was directly on CDBs and was often associated with the cross-connecting filaments (CCFs) (average diameter of 2-3nm) inside CDBs. We propose, based on these data, that desmin IFs, α-actinin-containing CCFs, and actin filaments are the principal components of the substructure of assembling CDBs. We also present a proposed model for CDB assembly. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970290303
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    Different reactivity with monoclonal anti-tubulin antibodies between native and fixed mitotic microtubules in sea urchin eggs (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 241-249 
    Details
    ISSN: 0886-1544
    Keywords: immunofluorescence ; microinjection ; mitotic apparatus ; monoclonal antibodies ; sand dollar egg ; tubulin isotypes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect on fixation on the reactivities of mitotic microtubules with monoclonal anti-tubulin antibodies was investigated by the indirect immunofluorescence procedure. All of the seven antibodies used intensely stained mitotic microtubules in sea urchin eggs lysed and fixed with methanol at -20°C, whereas only two of them stained the stabilized microtubules in the lysed eggs before the fixation. The other five did not stain the mitotic microtubules even after microtubule components other than tubulin were removed by treating the lysed eggs with 0.4 M KCl solution containing taxol. These results exclude the possibility that the fixation affects proteins, which interact with microtubules including microtubule-associated proteins (MAPs) and interfere with the binding of monoclonal antibodies with tubulin, and strongly suggest that the fixation directly affects the three-dimensional conformation of tubulin Furthermore, microinjection of these antibodies indicated the results as follows [combining the results reported previously; Oka et al., 1990: Cell Struct. Funct. 15: 373-378]: The antibodies which stained mitotic microtubules stabilized in the lysed eggs induced disassembly of native mitotic microtubules in the living eggs, but those which did not stain the stabilized microtubules did not disassemble the native microtubules. From these results, it is suggested that the monoclonal antibodies which stain microtubules in the eggs lysed but not fixed are useful for microinjection experiments. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970290307
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    Antibodies that can discriminate between dynein heavy chains and their HUV1 photoproducts (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 271-279 
    Details
    ISSN: 0886-1544
    Keywords: peptide antibodies ; protein processing ; axonemes ; microtubule associated proteins ; UV photocleavage ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Dyneins are multi-subunit enzymes that transduce chemical energy into the mechanical energy that makes cilia and flagella beat and moves organelles towards the minus end of microtubules. The ATPase activity is borne by heavy chains, and recent molecular analysis indicates that dynein heavy chain genes form an ancient multigene family: the similarity between the same isoform of two distantly related species is greater than that between different isoforms of the same species. We have exploited sequence identities between a Paramecium axonemal dynein heavy chain gene cloned in our laboratory and sequences of dynein heavy chains from other species to prepare antibodies against active-site peptides capable of recognizing dynein heavy chains regardless of species or isoform. One of the antibodies is perfectly specific for the larger product of V1 photolysis (HUV1) and thus incorporates a unique property of the hydrolytic ATP binding site of all known dynein heavy chains, the capacity for photocleavage in the presence of micromolar vanadate. Our characterization of these reagents suggests that they will be useful for biochemical and in situ studies of known dyneins as well as identification of potential new members of the family. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970290310
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    Characteristics of pronuclear migration in Beroe ovata (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 301-311 
    Details
    ISSN: 0886-1544
    Keywords: ctenophore ; egg ; nucleus ; microtubule ; endoplasmic reticulum (ER) ; sperm aster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the large eggs (∼1 mm) of the ctenophore Beroe ovata, female pronuclei migrate long distances to join stationary male pronuclei in the peripheral cytoplasm that surrounds the yolky interior. We have investigated the mechanism of nuclear migration using time lapse video recording, automated image analysis, visualization of microtubules by immunofluorescence and rhodamine-tubulin injection, and electron microscopy. Female pronuclei migrated at average speeds of 0.2 μm/sec, and were found to show periodic oscillations in velocity. Alternating phases of acceleration and deceleration occurred with an average periodicity of 235 seconds covering distances of 47 μm (about 3 times the nuclear diameter). Migration velocities and velocity oscillations were similar in fertilized and unfertilized eggs; however, changes in migration direction were much more frequent in unfertilized eggs. Characteristic deformations of the pronuclear membrane and occasional rotation of the nuclear contents were observed during migration. Inhibitor studies indicated that microtubules are required for nuclear migration. In fertilized eggs the top of the nucleus was found to move through the dense layer of aligned sperm aster microtubules. The frequent changes in direction of pronuclear migration in unfertilized eggs reflect the random organization of the microtubule layer in the absence of sperm derived centrosomes. Densely packed endoplasmic reticulum was found intermeshed with sperm aster microtubules and connected extensively with the nuclear membrane during migration. Most nuclear pores were grouped in an infolding of the nuclear membrane. We suggest that in fertilized eggs the female pronucleus is transported to the minus ends of sperm aster microtubules using motor molecules attached either to the outer nuclear membrane and/or to the network of connecting ER. © 1994 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970290403
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    Gain setting in Chlamydomonas reinhardtii: Mechanism of phototaxis and the role of the photophobic response (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 225-230 
    Details
    ISSN: 0886-1544
    Keywords: Weber's Law ; retinal ; retinal analogs ; photoreception ; alga ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The unicellular green alga Chlamydomonas reinhardtii maintains sensitivity of its phototaxis response (alignment of swimming direction along the axis of a light beam) over several orders of magnitude of light intensities. It is widely accepted that the rotation of the swimming cell provides temporal comparisons of light intensities via periodic contrast generated by its asymmetrically positioned refractile eyespot organelle. The cells also exhibit a second behavioral response to light called the photophobic (or stop) response, which is a brief cessation of swimming caused by a temporal change in light intensity. The cells are desensitized to photophobic stimuli by light exposure. Through comparative measurements of both responses, we explain the behavioral basis of the large dynamic range of phototaxis in terms of precise desensitization of the photophobic response. The basis of the explanation is that the flagellar beat changes which cause phototactic orientation are the residual of the photophobic response after desensitization (i.e., “mini-photophobic” reactions which cause brief reorienting motions without a full stop). This interpretation predicts quantitatively the dependence of the extent of desensitization on light intensity and the dependence of onset and maintenance of phototaxis on extent of desensitization. These predictions are tested and confirmed in this report. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970290305
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    Switching of the dominant calcium sequestering protein during skeletal muscle differentiation (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 259-270 
    Details
    ISSN: 0886-1544
    Keywords: calsequestrin ; calreticulin ; sarcoplasmic reticulum ; skeletal muscle ; myofibril ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A major Ca2+-storing protein in endoplasmic reticulum (ER) of non-muscle cells is calreticulin (CR), which is considered to be functionally homologous to calsequestrin. Calsequestrin is a Ca2+-binding protein in sarcoplasmic reticulum (SR) of striated muscle, which stores Ca2+ during muscle relaxation. In order to investigate the expression and distribution of calsequestrin and calreticulin during skeletal muscle differentiation, cultured chick embryonic skeletal muscles were observed by immunofluorescence using anti-calsequestrin, anti-calreticulin, antidesmin, and anti-sarcomeric myosin antibodies and rhodamine-phalloidin. Within 6 hours in culture, myoblasts started to express desmin. Desmin-positive cells demonstrated the reticular staining of calreticulin, as did desmin-negative cells. Around fusion, calsequestrin and sarcomeric myosin started to appear in desmin-positive cells. The expression of calsequestrin slightly preceded that of sarcomeric myosin. As the myotubes matured, the fluorescent dots of calsequestrin increased and spread to the cell periphery along the myofibrils, while the reticular pattern of calreticulin gradually disappeared. Double labeling showed that calsequestrin colocalized with calreticulin. In mature myotubes, anti-calsequestrin staining demonstrated many dots along myofibrils, whereas calreticulin was barely seen except at the perinuclear region. These results suggest that the expression of calsequestrin and calreticulin are switched during skeletal muscle differentiation. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970290309
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  • 89
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    Effect of protein kinase inhibitor H-7 on the contractility, integrity, and membrane anchorage of the microfilament system (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 321-338 
    Details
    ISSN: 0886-1544
    Keywords: protrusive activity ; adherens junctions ; stress fibers ; permeabilized cell models ; myosin light chain kinase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Addition of protein kinase inhibitor H-7 leads to major changes in cell structure and dynamics. In previous studies [Citi, 1992: J. Cell Biol. 117:169-178] it was demonstrated that intercellular junctions in H-7-treated epithelial cells become calcium independent. To elucidate the mechanism responsible for this effect we have examined the morphology, dynamics, and cytoskeletal organization of various cultured cells following H-7-treatment. We show here that drug treated cells display an enhanced protrusive activity. Focal contact-attached stress fibers and the associated myosin, vinculin, and talin deteriorated in such cells while actin, vinculin, and N-cadherin associated with cell-cell junctions were retained. Furthermore, we demonstrate that even before these cytoskeletal changes become apparent, H-7 suppresses cellular contractility. Thus, short pretreatment with H-7 leads to strong inhibition of the ATP-induced contraction of saponin permeabilized cells. Comparison of H-7 effects with those of other kinase inhibitors revealed that H-7-induced changes in cell shape, protrusional activity, and actin cytoskeleton structure are very similar to those induced by selective inhibitor of myosin light chain kinase, KT5926. Specific inhibitors of protein kinase C (Ro31-8220 and GF109203X), on the other hand, did not induce similar alterations. These results suggest that the primary effect of H-7 on cell morphology, motility, and junctional interactions may be attributed to the inhibition of actomyosin contraction. This effect may have multiple effects on cell behavior, including general reduction in cellular contractility, destruction of stress fibers, and an increase in lamellipodial activity. It is proposed that this reduction in tension also leads to the apparent stability of cell-cell junctions in low-calcium medium. © 1994 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970290405
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  • 90
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    Erratum (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 383-383 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290411
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  • 91
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    Axonemes paralyzed by the presence of dyneins unable to use ribose-modified ATP (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 161-168 
    Details
    ISSN: 0886-1544
    Keywords: fluorescent nucleotide analogs ; methylanthraniloyl ATP ; anthraniloyl ATP ; Chlamydomonas ; axonemal mutants ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Substrate analogs are useful for studying the structures of active sites and for distinguishing between similar enzyme activities. Fluorescent ribose-modified ATP analogs were used to investigate the functional differences between dynein ATPases. These analogs reactivate (support the movement of) sea urchin sperm axonemes, yet they do not reactivate wild-type Chalmydomonas axonemes. Surprisingly, the analogs reactivate the axonemes of mutants completely missing the outer arm dyneins. Competition experiments using ATP and these analogs provide strong evidence that the analogs bind to all dynein active sites but fail to release a subset of dyneins from rigor. We suggest that this subset of Chlamydomonas outer arm dyneins unable to use the analogs remains in rigor in the presence of the analogs and paralyzes the axoneme. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970270207
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  • 92
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    ATP-induced sliding of microtubules on tracks of 22S dynein molecules aligned with the same polarity (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 180-191 
    Details
    ISSN: 0886-1544
    Keywords: sliding movement ; 22S dynein ; Tetrahymena cilia ; dynein-track ; singlet microtubule ; ATP ; polarity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Chlamydomonas and Tetrahymena axonemal dyneins have previously been found to bind to porcine brain microtubules to produce a microtubule-dynein complex. At appropriate microtubule:dynein concentration, microtubules in the complex became covered to saturation by dynein arms of the same polarity and at a spacing of 24 nm [Haimo et al., 1979; Haimo and Fenton, 1988; Haimo, 1989; Porter and Johnson, 1983a].In the present study, two different types of microtubule-dynein complexes (α-and β-complexes) were prepared from Tetrahymena ciliary 22S dynein and porcine brain tubulin. The characteristics of the adenosine triphosphate (ATP)-induced extrusion of microtubules from these complexes were analyzed, as a simple and direct in vitro assay for the ATP-induced extrusion of single microtubules. The α-complex prepared by adding dynein to microtubules showed an interrupted sliding movement, which would stop and start several times following the addition of ATP. In the β-complex, prepared by adding dynein bound to DEAE-tubulin to pre-assembled microtubules, microtubules became covered with dynein molecules whose orientation and binding were uniform with respect to microtubule polarity. The microtubules in the β-complex extruded at 12 μm/second following the addition of ATP. Dark-field and electron microscopy indicated that the extruded microtubules had undergone sliding on a dynein-track that had become detached from the complexes and had been absorbed onto the surface of the glass slide. At higher light intensity under a dark-field microscope, the dynein-track was seen to be composed of rows of dynein molecules arranged densely. The orientation of dynein molecules in rows appeared to be uniform considering the images of bound dynein in the β-complex under electron microscope. The higher sliding velocity of the microtubules on these dynein-tracks compared to that seen on slides coated at random with dynein [Vale and Toyoshima, 1988, 1989], may be due to more efficient force generation by this dense arrangement of dynein molecules with the same polarity on the tracks. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970270209
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  • 93
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270101
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  • 94
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    Effects of thymosin β4 and thymosin β10 on actin structures in living cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 13-25 
    Details
    ISSN: 0886-1544
    Keywords: Tβ4 ; Tβ10 ; β-thymosins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The β-thymosins are a family of small proteins originally isolated from the thymus. Recently, two of the major mammalian isoforms, thymosin β4 (Tβ4) and thymosin β10 (Tβ10), are identified as significant actin monomer sequestering proteins which may be involved in regulating actin filament assembly. To study the cellular function of β-thymosins, we have used isoform-specific antibodies to determine their concentration and intracellular distribution, and examined the effects of inducing overexpression of Tβ4 and Tβ10 on actin filament structures. Immunofluorescence labeling of peritoneal macrophages showed that both β-thymosins are uniformly distributed within the cytoplasm. cDNA-mediated overexpression of β-thymosins in CV1 fibroblasts induced extensive loss of phalloidinstained actin stress fibers. Stress fibers in the cell center were more susceptible than those at the periphery. There was a decrease in the number of focal adhesions, as evidenced by a decrease in discrete vinculin staining and an increase in diffuse vinculin fluorescence. The majority of the transfected cells had normal shape in spite of extensive loss of actin filaments. Occasionally, cells overexpressing β-thymosin were observed to divide. In these cells, β-thymosin was excluded from the midbody which contains an actin filament-rich contractile ring. Our results indicate that Tβ4 and Tβ10 are functionally very similar and both are effective regulators of a large subset of actin filaments in living cells. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970270103
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  • 95
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    Regulation of dynein-driven motility in cilia and flagella (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 101-107 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270202
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  • 96
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    Cellular microtubules heterogeneous in their content of microtubule-associated protein 4 (MAP4) (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 133-149 
    Details
    ISSN: 0886-1544
    Keywords: MAP4 depletion ; antibody blocking ; detyrosination ; midbody ; asymmetric cell processes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Previous immunolocalization studies using many primate cultured cell lines demonstrated that a microtubule-associated protein of Mr ∼210,000 which is now called MAP4, is present along the length of microtubules in interphase and mitotic cells [Bulinski and Borisy (1980) J. Cell Biol. 87:802-808; DeBrabander et al. (1981) J. Cell Biol. 91:438-455]. Since MAP4 has been implicated as a microtubule stabilizer, we asked whether all classes of microtubules possess an equal complement of MAP4. We have reexamined the cellular distribution of MAP4, using both conventional double-label immunofluorescence and an antibody blocking technique [Schulze and Kirschner (1987) J. Cell Biol. 104:277-288] to highlight microtubules lacking, or depleted in, MAP4. These techniques have revealed that thin processes extending from monkey kidney cells (TC-7), and those made by human neuroblastoma cells (IMR-32) in response to retinoic acid, are often deficient in MAP4 immunoreactivity. Since both types of cellular processes contain stable microtubules, which are enriched in detyrosinated (Glu) tubulin, we tested the ability of MAP4 to bind to microtubules made from pure Glu and pure tyrosinated (Tyr) tubulin in vitro. MAP4 bound to both types of microtubules, and the similar saturation level of MAP4 binding to Glu and Tyr microtubules suggested that differential binding to these forms of tubulin does not contribute directly to a mechanism for segregation of MAP4 on microtubules in vivo. In TC-7 cells, we also observed MAP4-depletion on single microtubules, distal regions of broad cytoplasmic extensions, and midbodies of dividing cells. MAP4 depletion may reflect recent, rapid growth of microtubules to which MAP4 has not yet bound, or the presence of other MAPs that may compete with MAP4 for binding sites on the MT. We suggest that different levels of MAP4 on microtubules may directly modulate microtubule dynamics within single cells, as well as other microtubule functions such as those involving microtubule motor activity. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970270205
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  • 97
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    Differential distribution of glutamylated tubulin during spermatogenesis in mammalian testis (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 49-58 
    Details
    ISSN: 0886-1544
    Keywords: spermatozoa ; centriole ; axoneme ; immunogold ; acetylated tubulin ; tubulin heterogeneity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution of glutamylated tubulin has been analyzed in mammalian testis using the specific mAb GT335 by immunoelectron microscopy and immunoblotting. In spermatozoa of various species, immunogold labeling showed the presence of glutamylated tubulin in all of the microtubules of axoneme and centrioles, whereas the microtubule network of the spermatid manchette was unlabeled. In earlier germ cells, centriole was the only microtubule structure to be labeled. A similar distribution was observed using the anti-acetylated tubulin antibody (6-11B-1), confirming previous results of Hermo et al. [Anat. Rec. 229:31-50, 1991]. However, among testicular somatic cells, microtubules of some Sertoli cell branches were not acetylated but glutamylated. 2-D PAGE of mouse and hamster sperm extracts showed a high level of α and β-tubulin heterogeneity, comparable to that found in brain. Immunoblotting with GT335 revealed a large amount of glutamylated tubulin resolved into numerous α as well as β-tubulin isoforms. This suggests that the major testis-specific tubulin isotypes (mα3/7 and mβ3) are also glutamylatable. These results show a subcellular sorting of posttranslationally modified tubulin isoforms in spermatids, glutamylation being associated with the most stable microtubule structures. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270106
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    Announcements (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 97-97 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270111
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  • 99
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    Masthead (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270201
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  • 100
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    Effects of silver ions (Ag+) on contractile ring function and microtubule dynamics during first cleavage in Ilyanassa obsoleta (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 117-132 
    Details
    ISSN: 0886-1544
    Keywords: cleavage furrow ; cytokinesis ; intercellular bridge ; polar lobe constriction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The terminal phase of cell division involves tight constriction of the cleavage furrow contractile ring, stabilization/elongation of the intercellular bridge, and final separation of the daughter cells. At first cleavage, the fertilized eggs of the mollusk, Ilyanassa obsoleta, form two contractile rings at right angles to each other in the same cytoplasm that constrict to tight necks and partition the egg into a trefoil shape. The cleavage furrow contractile ring (CF) normally constricts around many midbody microtubules (MTs) and results in cleavage; the polar lobe constriction contractile ring (PLC) normally constricts around very few MTs and subsequently relaxes without cleavage. In the presence of Ag+ ions, the PLC 1) begins MT-dependent rapid constriction sooner than controls, 2) encircles more MTs than control egg PLCs, 3) elongates much more than control PLCs, and 4) remains tightly constricted and effectively cleaves the polar lobe from the egg. If Ag+-incubated eggs are returned to normal seawater at trefoil, tubulin fluorescence disappears from the PLC neck and the neck relaxes. If nocodazole, a drug that depolymerizes MTs, is added to Ag+-incubated eggs during early PLC constriction, the PLC is not stabilized and eventually relaxes. However, if nocodazole is added to Ag+-incubated eggs at trefoil, tubulin fluorescence disappears from the PLC neck but the neck remains constricted. These results suggest that Ag+ accelerates and gradually stabilizes the PLC constriction by a mechanism that is initially MT-dependent, but that progressively becomes MT-independent. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970270204
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