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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 213 (1992), S. 275-286 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Electromyographical (EMG) activity was recorded bilaterally from the masseter and temporalis muscles of alert ferrets (Mustela putorius furo) during mastication and crushing. Electromyographic activity was also recorded during biting while a bite-force transducer placed between the carnassial teeth registered forces ranging from 1.5 to 48.8 N. Linear regression analysis demonstrates that temporalis and masseter EMG activity are linearly related to bite force. Electromyographic activity from the balancing-side muscles is nearly equal to EMG activity of the working-side muscles during bone crushing with the carnassial teeth. It is hypothesized that a high percentage of balancing-side muscle activity in ferrets can be recruited during carnassial biting because the postglenoid process prevents ventral displacement of the working-side mandibular condyle. © 1992 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0886-1544
    Keywords: actomyosin ; smooth muscle contraction ; nonmuscle cell motility ; microinjection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of monoclonal anti-caldesmon antibodies, C2, C9, C18, C21, and C23, on the binding of caldesmon to F-actin/F-actin-tropomyosin filaments and to Ca++/calmodulin were examined in an in vitro reconstitution system. In addition, the antibody epitopes were mapped by Western blot analysis of NTCB (2-nitro-5-thiocyanobenzoic acid) and CNBr (cyanogen bromide) fragments of caldesmon. Both C9 and C18 recognize an amino terminal fragment composed of amino acid residues 19 to 153. The C23 epitope lies within a fragment ranging from residues 230 to 386. Included in this region is a 13-residue repeat sequence. Interestingly this repetitive sequence shares sequence similarity with a sequence found in nuclear lamin A, a protein which is also recognized by C23 antibody. Therefore, it is likely that the C23 epitope corresponds to this 13-residue repeat sequence. A carboxyl-terminal 10K fragment contains the epitopes for antibodies C2 and C21. Among these antibodies, only C21 drastically inhibits the binding of caldesmon to F-actin/F-actin-tropomyosin filaments and tc Ca++/calmodulin. When the molar ratio of monoclonal antibody C21 to caldesmon reached 1.0, a maximal inhibition (90%) on the binding of caldesmon to F-actin filaments was observed. However, it required double amounts of C21 antibody to exhibit a maximal inhibition of 70% on the binding of caldesmon to F-actin-tropomyosin filaments. These results suggest that the presence of tropomyosin in F-actin enhances caldesmon's binding. Furthermore, C21 antibody also effectively inhibits the caldesmon binding to Ca++/calmodolin. The kinetics of C21 inhibition on caldesmon's binding to Ca++/calmodulin is very similar to the inhibition obtained by preincubation of caldesmon with free Ca++/calmodulin. This result suggests that there is only one Ca++/calmodulin binding domain on caldesmon and this domain appears to be very close to the C21 epitope. Apparently, the Ca++/calmodulin-binding domain and the actin-binding domain are very close to each other and may interfere with each other. In an accompanying paper, we have further demonstrated that microinjection of C21 antibody into living chicken embryo fibroblasts inhibit intracellular granule movement, suggesting an in vivo interference with the functional domains [Hegmann et al., 1991: Cell Motil. Cytoskeleton 20:109-120].
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 18 (1991), S. 304-318 
    ISSN: 0886-1544
    Keywords: mitosis ; spindle ; chromosome ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mitotic spindles isolated from sea urchin eggs can be reactivated to undergo mitotic processes in vitro. Spindles incubated in reactivation media containing sea urchin tubulin and nucleotides undergo pole-pole elongation similar to that observed in living cells during anaphase-B. The in vitro behavior of spindles isolated during metaphase and anaphase are compared. Both metaphase and anaphase spindles undergo pole-pole elongation with similar rates, but only in the presence of added tubulin. In contrast, metaphase but not anaphase spindles increase chromosome-pole distance in the presence of exogenous tubulin, suggesting that in vitro, tubulin can be incorporated at the kinetochores of metaphase but not anaphase chromosomes. The rate of spindle elongation, ultimate length achieved, and the increase in chromosome-pole distance for isolated metaphase spindles is related to the concentration of available tubulin. Pole-pole elongation and chromosome-pole elongation does not require added adenosine triphosphate (ATP). Guanosine triphosphate (GTP) will support all activities observed. Thus, the force generation mechanism for anaphase-B in isolated sea urchin spindles is independent of added ATP, but dependent on the availability of tubulin. These results support the hypothesis that the mechanism of force generation for anaphase-B is linked to the incorporation of tubulin into the mitotic apparatus. (If, in addition, a microtubule-dependent motor-protein(s) is acting to generate force, it does not appear to be dependant on ATP as the exclusive energy source).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0886-1544
    Keywords: human fibroblast tropomyosins ; normal and transformed cells ; actin-binding protein ; cDNA cloning ; expression of tropomyosin isoforms ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A tropomyosin-specific oligonucleotide probe (REN29) designed to hybridize to all known human tropomyosin isoforms was used to study tropomyosin mRNA levels in normal and transformed human cells. At least four different sizes of RNAs were detected in normal human fibroblast KD cells by Northern blot analysis. The major bands of 1.1 kb RNA for hTM1 and 3.0 kb RNA for hTM4 were decreased substantially in various transformed cell lines. One of the minor RNA bands (2.0 kb for hTM2 and hTM3) appeared to be absent in a human pancreatic carcinoma cell line. The level of the other minor RNA band (2.5 kb for hTM5) was found to be unchanged or slightly decreased in transformed cells. This differential expression of tropomyosin isoforms at the RNA level was not totally in agreement with the difference in the protein amounts found in normal and transformed cells, suggesting that translational control may also play an important role in the expression of some tropomyosin isoforms. The REN29 probe was further used to screen γgt10 and γgt11 cDNA libraries, which were constructed from poly(A)+ RNAs of human fibroblast cell lines HuT-14 and WI-38, respectively. In addition to cDNA clones encoding known isoforms, we obtained three classes of new cDNA clones that encode two low Mr isoforms (hTM5a and hTM5b), and a high Mr isoform (hTMsmα). Sequence comparison revealed that hTM5a and hTM5b are alternatively spliced products derived from the same gene that encodes hTM2 and hTM3. Northern blot analysis and amino acid sequence comparison suggested that the hTMsmα represents a smooth muscle tropomyosin which is also expressed in human fibroblasts. The exon specific for, and common to, hTM5a and hTM5b was found to be highly expressed in small intestine. However, there was no detectable expression of this exon in stomach and skeletal muscle. The difference in tissue-specific expression suggests that different isoforms may perform distinct functions in different tissues. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 336-344 
    ISSN: 0886-1544
    Keywords: MTOC ; dendrites ; neurite extension ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Centrosomes are unique cytoplasmic structures which serve as microtubule organizing centers (MTOC). In most animal cells centrosomes consist of one or more pair of centrioles surrounded by electron dense amorphous pericentriolar material (PCM) responsible for nucleation of microtubules. In the present study we analyzed the pattern of induction and localization of proteins of the PCM at different stages of neuronal development in cell cultures prepared from the embryonic hippocampus. For this purpose we used a human polyclonal antibody that recognizes two proteins of the PCM (100 kd and 60 kd, respectively). The results indicate that in mature neurons, pericentriolar immunoreactive material is preferentially localized in dendritic processes, and that throughout the course of neurite development and differentiation it is systematically excluded from the neuron's axon. Western blot analysis showed that during neuronal development in situ, there is an increase in he immunoreactivity for both proteins recognized by this antibody. In contrast, in hippocampal pyramidal neurons that develop in culture, there is an increase in the 60 kd polypeptide, while the 100 kd one is not detected after 7 days in vitro. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 248-261 
    ISSN: 0886-1544
    Keywords: human fibroblast tropomyosins ; actin-binding protein ; caldesmon ; actin-tropomyosin-activated HMM ATPase ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: At least eight tropomyosin isoforms (hTM1, hTM2, hTM3, hTM4, hTM5, hTM5a, hTM5b, and hTMsmα) are expressed from four distinct genes in human fibroblasts. In order to elucidate isoform properties, we have subcloned hTM3 and hTM5 full-length cDNAs, as well as their chimeric cDNAs into the bacterial expression pET8C system. Bacterially expressed tropomyosin isoforms (called PEThTM3, PEThTM5. PEThTM5/3, and PEThTM3/5) were purified and characterized. Under optimal binding conditions, the binding of PEThTM5 isoform to F-actin was stronger than the PEThTM3 isoform. However, analysis of actin-binding by the McGhee and von Hippel equation revealed that PEThTM3 exhibits higher cooperativity in binding than PEThTM5 does. Furthermore, the chimera PEThTM5/3 which possessed the N-terminal fragment of hTM5 fused to the C-terminal fragment of hTM3 had even stronger actin binding ability. The reverse chimera PEThTM3/5 which possessed the N-terminal fragment of hTM3 fused to the C-terminal fragment of hTM5 demonstrated greatly reduced affinity to actin filaments. In addition, both chimeras had different KCl requirements for optimal binding to F-actin than their parental tropomyosins. A bacterially made C-terminal fragment of human fibroblast caldesmon (PETCaD39) and native chicken gizzard caldesmon were both able to enhance the actin-binding of these bacterially expressed tropomyosins. However, PETCaD39′s enhancement of binding to F-actin was greater for PEThTM5 than PEThTM3. Under 30 mM KCl and 4 mM MgCl2, the low Mr isoform PEThTM5 appeared to be able to amplify the actin-activated HMM ATPase activity by 4.7 fold, while the high Mr isoform PEThTM3 stimulated the activity only 1.5 fold. The higher enhancement of ATPase activity by PEThTM5 than by PEThTM3 suggested that the low Mr isoform hTM5 may be more involved in modulating nonmuscle cell motility than hTM3. These results further suggested that different isoforms of tropomyosin might have finite differences in their specific functions (e.g., cytoskeletal vs. motile) inside the cell. © 1993 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 17 (1990), S. 6-10 
    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
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Clinical Anatomy 6 (1993), S. 247-254 
    ISSN: 0897-3806
    Keywords: Donation of body/organs/tissues - law and legislation ; history ; social aspects ; ethics ; Organ transplantation - law and legislation ; Willedbody programs ; Life and Medical Sciences ; Miscellaneous Medical
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Although many are aware of the existence of a document called the Uniform Anatomical Gift Act (UAGA), few are aware that there are actually two such Acts (1968 and 1987), and even fewer have read the Acts themselves. Consequently, there are many different and frequently false impressions about their purpose and content. This paper is an attempt to acquaint readers with the two UAGAs. The historical background leading to the unprecedented rapid, uniform and unanimous adoption of the 1968 Act is presented. The content, rationale, and significance of that Act are outlined. The perceived shortcomings of the first Act resulting in the much less successful and less widely-adopted 1987 Act is explained and the major changes incorporated in the second Act are outlined. Specific features of the Acts of concern to anatomists involved in willed-body programs, and clinicians who may become involved in body/body part donation or utilization are addressed. Finally, the relationship of the UAGA to other lines of regulation and the need to be aware of them is indicated. © 1993 Wiley-Liss, Inc.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 226 (1990), S. 147-152 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Transverse histological sections from T10-11, T11-12, T12-L1, and L1-2 zygapophyseal joints were examined in 32 post-mortem spines, using light microscopy, to record the presence of intra-articular synovial fold inclusions. In addition, three mid-joint sections from each joint were photographed using 35 mm colour film. From these slides, linear dimensions of the extent of intraarticular synovial fold projection between the zygapophyseal joints were measured using computer-aided planimetry. Small, fibrous folds were commonly found at the joint margins extending from the ligamentum flavum and the fibrous joint capsule. Larger, fibro-adipose synovial folds, projecting between the articular surfaces, were also noted, particularly at T12-L1 and L1-2.
    Additional Material: 6 Ill.
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  • 10
    ISSN: 0003-276X
    Keywords: Respiratory Biology ; Pulmonary hypoplasia ; Lung pathology ; Chondrodystrophy ; Mouse ; Embryo/fetus ; Ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: Fetal mice homozygous for the Disproportionate micromelia (Dmm) gene were studied as a model for pulmonary hypoplasia in chondrodystrophy.Methods: Wet weight, dry weight, and biochemical content were determined in excised whole lungs, terminal sac morphology and presence of multilamellar bodies were determined by electron microscopy, and volume of the thoracic space was estimated from paraffin casts. Lung development of the mutant was further assessed in whole organ culture.Results. Compared with normal littermates, the mutant showed a significant decrease (28%) in lung wet weight without showing altered lung dry weight or tissue content of DNA and protein. The terminal sacs of lungs fixed by intratracheal instillation were significantly smaller than normal. However, the lungs appeared to have undergone maturation on schedule since the surfactant precursors, multilamellar bodies, were observed and normal tissue-levels of phospholipid were detected. The volume of the mutant's thorax was markedly reduced. Finally, the mutant's lungs when removed from the fetus prior to the onset of thoracic dystrophy (day 15) and cultured for three days demonstrated that, without the confining influence of a reduced thoracic space, they are capable of development comparable to normal.Conclusions: These findings support the hypothesis that the Dmm mutant can be further studied as a model for human pulmonary hypoplasia associated with chondrodystrophy, and that the relationship between the reduced thorax and the lung disorder is cause-and-effect. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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