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  • 1
    Electronic Resource
    Electronic Resource
    The role of glycation cross-links in diabetic vascular stiffening (1996)
    Springer
    Diabetologia 39 (1996), S. 946-951 
    Details
    ISSN: 1432-0428
    Keywords: Diabetes mellitus ; glycation ; cross-links ; vascular stiffening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previous studies have shown that biomechanical analysis of aorta from diabetic subjects reveals a marked increase in stiffness compared to aorta from age-matched control subjects. In the present paper we have proposed that this increased stiffness can be attributed to glycation-induced inter-molecular cross-links based on a direct analysis of the two known glycation cross-links, the fluorescent pentosidine and the non-fluorescent NFC-1. There was a significant difference in the increase in concentration of both cross-links with increasing age for both the intima (p〈0.0025) and the media (p〈0.0005) from the diabetic compared to the control subjects, but no correlation with the mature enzymic cross-link hydroxylysyl-pyridinoline. Finally, we have obtained a significant correlation of stiffness with both glycation cross-links (NFC-1, r=0.86; p〈0.005 and pentosidine r=0.75, p〈0.05), but the concentration of NFC-1 is about 50 times greater than that of pentosidine, indicating that it is the major glycation cross-link responsible for the stiffening of the aorta.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403914
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  • 2
    Electronic Resource
    Electronic Resource
    The role of glycation cross-links in diabetic vascular stiffening (1996)
    Springer
    Diabetologia 39 (1996), S. 946-951 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Diabetes mellitus ; glycation ; cross-links ; vascular stiffening.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previous studies have shown that biomechanical analysis of aorta from diabetic subjects reveals a marked increase in stiffness compared to aorta from age-matched control subjects. In the present paper we have proposed that this increased stiffness can be attributed to glycation-induced inter-molecular cross-links based on a direct analysis of the two known glycation cross-links, the fluorescent pentosidine and the non-fluorescent NFC-1. There was a significant difference in the increase in concentration of both cross-links with increasing age for both the intima (p 〈 0.0025) and the media (p 〈 0.0005) from the diabetic compared to the control subjects, but no correlation with the mature enzymic cross-link hydroxylysyl-pyridinoline. Finally, we have obtained a significant correlation of stiffness with both glycation cross-links (NFC-1, r = 0.86; p 〈 0.005 and pentosidine r = 0.75, p 〈 0.05), but the concentration of NFC-1 is about 50 times greater than that of pentosidine, indicating that it is the major glycation cross-link responsible for the stiffening of the aorta. [Diabetologia (1996) 39: 946–951]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403914
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  • 3
    Electronic Resource
    Electronic Resource
    Glial proliferation in the irradiated rat spinal cord (1985)
    Springer
    Acta neuropathologica 68 (1985), S. 169-172 
    Details
    ISSN: 1432-0533
    Keywords: Astroglia ; Oligodendroglia ; Gliogenesis ; Developing spinal cord ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The identity of mitotic cells in the ventral half of the irradiated spinal cord in 13-day-old rats was studied by light and electron microscopy. At this post-irradiation interval, astrocytes as well as oligodendrocytes are markedly reduced in both gray and white matter, and few myelin sheaths are present. Earlier studies showed incorporation of3H-thymidine into cells identified light-microscopically as neuroglia. In the present study, a number of mitotic cells were identified in thick plastic sections. When adjacent thin sections were examined by electron microscopy, these mitotic cells were identified ultrastructurally as astroglia on the basis of the bundles of filaments in their cytoplasm and the irregular outline of the cell body and its processes. It is apparent from this study that astroglia proliferate prior to the delayed myelination that occurs later in the glial cell deprived ventral irradiated cord.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688641
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  • 4
    Electronic Resource
    Electronic Resource
    Transplantation of sciatic nerve segments into normal and glia-depleted spinal cords (1999)
    Springer
    Experimental brain research 125 (1999), S. 495-501 
    Details
    ISSN: 1432-1106
    Keywords: Key words CNS regeneration ; Transplantation ; Nerve grafts ; Spinal cord ; Astrocytic scars
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Although peripheral nerves are used as guides in attempts to enhance regeneration in the central nervous system (CNS), surprisingly little is known about the interface that develops between the host tissue and the transplanted or implanted peripheral nerve. This study examines host-nerve interfaces following transplantation of segments of sciatic nerve into the spinal cord under two differing conditions, one in which the spinal cord contains normal numbers of glia and one in which the glial population is reduced. The depletion of the glial population is achieved by exposing the lumbosacral region of the spinal cord in 3-day-old rats to X-rays, a model developed in this laboratory. Twenty days later, segments of fresh or frozen sciatic nerves harvested from other 3-day-old rats were transplanted into the lumbar region of spinal cord in irradiated animals and in their non-irradiated littermate controls. Following a 20-day postoperative period, the interfaces between host spinal cord and sciatic nerves were examined ultrastructurally, and pronounced differences were noted. A distinct scar composed of multiple layers of astrocyte processes completely enveloped the transplant in non-irradiated host spinal cord and confined Schwann cells and fibroblasts to the area enclosed by the scar. Terminals from axons that appeared to have traversed the transplant during this 20-day period ended blindly in the astrocytic scar. In contrast, a complete astrocytic scar failed to form around the transplant in the irradiated, glia-depleted hosts, and Schwann cells intermingled with host tissue. Some Schwann cells migrated away from the transplant, which was placed in the dorsal funiculus, along a perivascular route and extended into the gray matter. In some instances Schwann cells were observed in the ventral gray surrounding blood vessels and motoneurons. From these observations, it is clear that the formation of a distinct astrocytic barrier at the host-graft interface is greatly reduced irradiated host. The effects of astrocyte reduction on enhanced regeneration within the spinal cord are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050707
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  • 5
    Electronic Resource
    Electronic Resource
    Ovine periodontitis as a potential model for periodontal studies (2003)
    Oxford, UK : Munksgaard International Publishers
    Journal of clinical periodontology 30 (2003), S. 0 
    Details
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objectives:  To investigate infection and host immunity patterns in sheep with naturally occurring “broken-mouth” periodontitis.Materials and Methods:  Eight periodontally healthy (HS) and eight periodontally diseased ewes (PDS) were selected. Subgingival plaque and sera were collected and examined for evidence of human periodontitis-associated pathogens. Serum IgG titers were measured by ELISA to multiple strains of Porphyromonas gingivalis, Bacteroides forsythus, Dichelobacter nodosus, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum as well as several purified antigens (cysteine proteases, LPS, K, and fimbriae).Results:  Neither the organism Aa nor antigens to Aa were found in any animal. Most animals were positive for Pg, Bf, and Pi, but DNA probes detected no difference between HS and PDS relative to amounts of pathogens in subgingival plaque. PDS had significantly higher serum IgG titers to all Pg strains, to 50% of Bf strains, to the Pi and Fn strains, and to fimbriae and the two cysteine proteases (p-values ranging from 0.05 to 0.001). Regression analysis demonstrated a significant association between number of teeth lost and serum IgG antibody titers to whole-cell sonicate antigens of P. gingivalis strains (p〈0.01) and body weight (p〈0.01).Conclusions:  The presence of pathogens associated with periodontitis was reflected in differences in serum IgG titers between healthy and diseased sheep. This may have influenced animal body weight and might have systemic health and economic consequences. The data suggest that susceptible and non-susceptible sheep can be identified for periodontal research.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-051X.2003.10104.x
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  • 6
    Electronic Resource
    Electronic Resource
    Abnormal leukocyte motility in patients with early-onset periodontitis (1984)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 19 (1984), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.1984.tb01321.x
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  • 7
    Electronic Resource
    Electronic Resource
    Influence ofL-arginine on glucose mediated collagen cross link precursors in patients with diabetes mellitus (1991)
    Springer
    Amino acids 1 (1991), S. 73-80 
    Details
    ISSN: 1438-2199
    Keywords: Collagen cross links ; Glucose mediated cross links ; Diabetes mellitus ; L-arginine ; Long term complications ; Hexosyl lysines ; Glycosylated lysines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Long term complications of diabetes mellitus are largely due to chemical, structural and mechanical changes of connective tissue proteins involving glucose mediated collagen cross links (GMCC). To date there are only experimental therapeutic approaches for preventing long term complications of diabetes mellitus using the toxic substance aminoguanidine.L-arginine, a nontoxic substance, has been shown to reduce GMCC in animal models of diabetes mellitus. We have now performed a blind placebo controlled study with crossing over of two treatment periods of three months each in 29 patients with diabetes mellitus in order to examine the effect of treatment withL-arginine (2 × 1g daily) on glucose mediated collagen cross links (GMCC). GMCC was evaluated by determining glycosyl lysine (hexosyl lysine) levels in skin punch biopsies. Patients treated byL-arginine showed significantly lower GMCC precursors of skin collagen compared with the placebo treated group (difference of hexosyl lysine as counts/mL/ug hydroxyproline between the first and second skin biopsy 0.11 ± 4.44 vs. 4.03 ± 5.27,t = 2.17,p 〈 0.05). The only side effects ofL-arginine were gastric pain occurring only in patients who did not follow the instructions to takeL-arginine at meals. We conclude thatL-arginine could be useful for treating long term complications of diabetes mellitus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00808093
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  • 8
    Electronic Resource
    Electronic Resource
    Age-Related Changes in the Biochemical Properties of Human Cancellous Bone Collagen: Relationship to Bone Strength (1999)
    Springer
    Calcified tissue international 65 (1999), S. 203-210 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Collagen — Bone strength — Aging — Iliac crest bone biopsy — Bone turnover.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. The metabolism of bone collagen has received little attention in relation to age-related loss of bone mass and strength. The aim of the present study was to analyze bone collagen content and metabolism in human bone with respect to age. The material consisted of iliac crest bone biopsies from 94 individuals: 46 women (ages 18–96, mean age 60.8 years) and 48 men (ages 23–92, mean age 59.5 years). Excluded from the study were all individuals with known osteoporotic lumbar vertebral fractures and renal, hepatic, or malignant diseases. Prior to collagen analysis the biopsies were scanned in a pQCT scanner for density assessment and then tested biomechanically. The results showed a decline in apparent bone density with age (P 〈 0.0001), a decline in maximum stress, Young's modulus, and energy absorption with age (P 〈 0.001). Concomittantly, there was an age-related decline in the intrinsic collagen content with age (P 〈 0.001). However, there were no biochemical modifications of the bone collagen during aging. There were no significant differences between women and men in the slopes of the regressions-curves. When multiple regression analyses were performed, only apparent bone density came out as a significant contributor in the correlation to biomechanical properties. Nevertheless, the decrease in bone collagen content with age might indicate an increase in the mineralization degree (probably due to decreased bone turnover) and thereby a change in material properties of bone. In conclusion, the present study has shown that loss of bone mass plays the major role in loss of bone strength. However, there is also a change in bone composition during normal aging, leading to a decrease in collagen content and an increase in the degree of mineralization. At this skeletal site, in a normal population there was no change in the biochemical properties of bone collagen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900683
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  • 9
    Electronic Resource
    Electronic Resource
    Regeneration of dorsal root axons into experimentally altered glial environments in the rat spinal cord (1994)
    Springer
    Experimental brain research 99 (1994), S. 25-33 
    Details
    ISSN: 1432-1106
    Keywords: Regeneration ; Schwann cells Glial environment ; X-Irradiation ; Astrocytes ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Exposure of the lumbar spinal cord of rats to X-rays 3 days after birth results in changes in the composition of central glia. Shortly after irradiation, there is both retardation of central myelin formation and a loss of integrity of the astrocyte-derived glia limitans on the dorsal surface of the cord. Subsequently, Schwann cells invade, undergo division and myelinate axons in the dorsal funiculi in the irradiated region of the cord, creating there an environment similar to that of peripheral nerve. The present study was undertaken to compare the ability of lesioned dorsal root axons to grow back into the altered glial environments that exist within the spinal cord after irradiation. This regrowth was assessed by injecting Fluoro-Gold into the spinal cord and subsequently examining neurons in the dorsal root ganglia (DRG) for the presence of this label. Numbers of retrogradely labeled neurons were counted in the DRG in both injured and contralateral non-injured sides. Non-irradiated control rats had almost no labeled DRG neurons on the injured side, whereas Fluoro-Gold labeled neurons were observed in substantial numbers in the DRG on the injured side of irradiated rats. There was a definite trend in the data, indicating that the longer the interval between irradiation and root injury, the greater the number of labeled neurons. Since the Fluoro-Gold labeling technique does not allow for visualization of the labeled axons within the spinal cord, a few animals were used to assess anterograde labeling with wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP/HRP) from the dorsal root into the spinal cord. HRP-filled regenerating axons were visualized in dorsal white and gray matter of the irradiated spinal cord. Such axons were not present in the non-irradiated spinal cords. Radiation-induced changes in glial populations are discussed, particularly with regard to the temporal sequence of these changes and their possible relationship to the conversion of a normally non-permissive environment into one conducive to axonal regrowth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00241409
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  • 10
    Electronic Resource
    Electronic Resource
    Interactions between Schwann cells and CNS axons following a delay in the normal formation of central myelin (1989)
    Springer
    Experimental brain research 75 (1989), S. 513-522 
    Details
    ISSN: 1432-1106
    Keywords: Spinal cord ; Myelin ; Oligodendrocyte ; Schwann cells ; Tropic signals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Irradiation of the rat spinal cord during the first postnatal week results in a profound reduction of oligodendrocyte myelin formation in the dorsal funiculi (DF). Despite this absence of myelin, however, axons in the irradiated region in the DF increase in diameter and approximate the size distribution seen in the control spinal cord. By 25 days of age Schwann cells are present in the irradiated DF where they undergo cell division and myelinate the axons. During the early stages of this myelin formation, these intraspinal Schwann cells exhibit a relationship to axons that is somewhat different from that seen in the normal developing peripheral nervous system (PNS). For example, within a given region, intraspinal Schwann cells myelinate axons of large diameter prior to ensheathing bundles of small diameter axons. Additionally, during myelination a Schwann cell will surround a single axon with multiple processes which appear to compete for contact with the axolemma. On axons of larger diameter, the elaboration of these processes is so excessive that it is often difficult to trace them back to the parent Schwann cell. Later, when a single process establishes several spirals about an axon, additional processes are no longer elaborated, and the “extra” processes disappear as myelin formation advances to the stage of compact lamellae. Thereafter, the myelin sheath continues to form in a normal manner. Excess processes have been observed during myelinogenesis in the normal developing PNS, but their frequency in that environment is much less than in the irradiated cord. These observations support the hypothesis that the signal(s) to initiate myelin formation are expressed on the axolemmal surface and are controlled by the neuron. In addition, these observations suggest that the delay in myelination results in an affinity or tropism between axons and Schwann cells which exceeds the level existing at the normal time of myelin formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249902
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