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Biomedical subjects

R Silberberg

Publications and source records attributed to R Silberberg.

At least 19 recordsLinked to original sources
PubMed1989

Fibronectin content of the annulus fibrosus in diabetic and non-diabetic sand rats.

Annulus fibrosus of intervertebral discs from diabetic and non-diabetic sand rats were examined by microspectrophotometry for fibronectin content. This was higher in the diabetic animals both in the dorsal and ventral parts and in the outer and inner lamellae of the annulus. It is suggested that diabetes-related changes in fibronectin are similar to changes in annular collagen observed in species other than sand rats.

Animals↗
PubMed1989

Age-related changes in fibronectin in annulus fibrosus of the sand rat (Psammomys obesus).

Fibronectin stains were carried out and evaluated by microspectrophotometric techniques in annuli fibrosi of vertebral discs of sand rats (Psammomys obesus) of both sexes and two age groups, 13-18 months and over 2 years of age. The distribution of fibronectin in the annulus shows a centripetal gradient from the outer to the inner laminae. Fibronectin was significantly more abundant in the annuli of old than of young animals of corresponding sex. Sex differences were not significant. The dorsal segment contained more fibronectin than the ventral, but the difference was statistically significant only in the aged females. The outer laminae of the annuli appeared consistently higher in fibronectin content than the inner laminae.

Aging↗
PubMed1988

Histologic and morphometric observations on vertebral bone of aging sand rats.

The trabecular bone of the vertebrae of 30 male and 30 female sand rats (Psammomys obesus) aged 13 to 33 months was examined histologically and morphometrically. The usual age-linked decline of bone mass failed to occur in females and was statistically not significant in males. A few changes with age were noted at the cellular level. Sex differences were statistically significant only in animals living into the third year of life, males having a smaller bone mass than females. This abnormality of the vertebral spongiosa is attributed to pathologic local stresses caused by the numerous instances of disc degeneration and herniation. Differences in size, location, and age of the herniations are thought to account for the wide fluctuations in the individual bone parameters examined. Whereas the spine of the sand rat provides an excellent model for the study of spondylosis, it is unsuited as a model for age-linked osteoporosis.

Aging↗
PubMed1986

Effects of hyperinsulinism and of diabetes on proteoglycans of the intervertebral disc in weanling sand rats.

Weanling sand rats (Psammomys obesus) develop hyperinsulinemia or diabetes or both, if fed a standard laboratory diet without a supplement of fiber rich salt bush. The annuli fibrosi of hyperinsulinemic or diabetic animals, which are still hyperinsulinemic, show a slight but statistically significant increase in chondroitin sulfate and a lesser, statistically nonsignificant increase in keratan sulfate. Possible causes of these changes are discussed and the likelihood of a role of hyperinsulinism in their production is pointed out.

Animal Feed↗
PubMed1979

Diastropic dwarfism: a histochemical and ultrastructural study of the endochondral growth plate.

Chondro-osseous tissue from five patients with diastropic dwarfism was studied by histologic, histochemical, and electron microscopic methods. The major abnormalities observed were: 1) irregular distribution of chondrocytes undergoing degeneration in the resting cartilage; 2) abnormal distribution of collagens in the resting cartilage; 3) a spectrum of fibrous matrix lesions in the resting cartilage which ranged from focal areas of aggregated collagen fibrils to large cystic lesions in which intracartilagenous ossification occurred; and 4) shortened, irregular cellular columns within the growth plate which were occasionally disrupted by matrix lesions extending from the resting cartilage. These alterations in chondro-osseous morphology have not been observed in any of the other skeletal dysplasias examined to date and appear to be pathognomonic for this disorder.

Adolescent↗
PubMed1979

Degeneration of the intervertebral disks and spondylosis in aging sand rats.

Aging sand rats (Psammomys obesus) kept on a standard laboratory diet supplemented by salt bush--their natural source of food--were examined for changes of the vertebral column. From about 6 months of age on, degeneration of the intervertebral disks was noted. The changes increased in severity with increasing age, and from 1 1/2 years of age on, massive multiple disk herniations were seen. Associated with these lesions were spondylosis of "intervertebral" as well as hyperostotic type, and osteoarthrosis of the apophyseal joint. The sand rat seems to be an excellent model for the study of the pathogenesis of spinal diseases associated with the aging process.

Aging↗
PubMed1977

Epiphyseal growth and osteoarthrosis in blotchy mice.

Blotchy mice which carry a gene causing inadequate cross-linking of collagen were investigated for the progress of epiphyseal growth and for the appearance of changes in the knee joints following cessation of growth. In male mice of the strain, which are hemizygous for the gene, early growth proceeded in a histologically normal fashion, although the metaphyseal bone was less abundant than usual. From the age of 3 1/2 months on, the animals developed osteoarthrosis of the knee joints and at the time of death at 5-6 1/2 months of age, 88% of the animals had osteoarthrosis. The findings are discussed with special reference to a possible role of the collagen of the articular cartilage in the pathogenesis of some forms of osteoarthrosis.

Animals↗
PubMed1977

Enzyme studies in the articular cartilage of diabetic rats and of rats bearing transplanted pancreatic islets.

The articular cartilage of normal rats, of rats made diabetic with streptozotocin, and of rats made diabetic with streptozotocin and subsequently transplanted with isologous pancreatic islets was examined for the activities of enzymes engaged in the synthesis and degradation of glycosaminoglycans (mucopolysaccharides). The activities assayed were those of the degrading enzymes B-glucuronidase, B-acetyglucosaminidase, B-acetylgalactosaminidase, B-galactosidase, and those active in synthesis: uridine diphosphate dehydrogenase, glucose-6-phosphate dehyrogenase, and phosphofructokinase. In the diabetic animals all enzyme activities were increased, thos of the degrading enzymes more than those of the others. Implantation of pancreatic islets reversed the changes produced by diabetes, enzyme activities returning to near-normal levels.

Acetamides↗
PubMed1976

Ultrastructure of articular cartilage of achondroplastic mice.

Articular chondrocytes of achondroplastic mice (cn/cn) resemble ultrastructurally those of their non-achondroplastic siblings (Cn/Cn or Cn/cn), except for premature deposition of glycogen and a tendency to undergo regression. The latter may be slight or extreme. The ultimate cause of the vulnerability of the chondrocytes and the cause of the heterogeneity of the reaction could not be determined with the method employed. Nevertheless, increased vulnerability accounts for cell death under conditions which are usually not injurious, and which may be either physiologic or altered by endogenous or exogenous factors.

Achondroplasia↗
PubMed1976

Obesity and joint disease.

In male mice of strain C57Bl, obesity caused by intraperitoneal administration of aurothioglucose failed to alter the course of spontaneous osteoarthrosis. The distribution of osteoarthrosis of the knee joint and of spondylosis of the thoracic and lumbar spine was haphazard in regard to body weight, and levels of plasma and hepatic lipids. It is concluded that the arthrosis-promoting effects of fat-enriched diets are not mediated by the simultaneously occurring obesity.

Aging↗
PubMed1976

Aging changes in intervertebral discs and spondylosis in Chinese hamsters.

Vertebrae and intervertebral discs of Chinese hamsters, a species of rodents that develop spontaneous diabetes, were investigated for age-linked changes and for the occurrence of spondylosis. Aging changes in the intervertebral discs were similar in diabetic and nondiabetic animals. The incidence of spondylosis was significantly increased and its onset was accelerated in the diabetic animals. The mechanisms operative in the pathogenesis of the lesions and their relation to the human disease are discussed.

Aging↗
PubMed1976

Articular cartilage of diabetic Chinese hamsters.

Investigations were carried out in order to determine whether animals with spontaneous diabetes are prone to develop skeletal lesions comparable to those found in diabetic human subjects. The present report deals with the ultrastructure of the cartilage of the hip joint of diabetic Chinese hamsters and nondiabetic control animals. In the diabetic animals, chondrocytes of the femoral head showed atrophy of the endoplasmic reticulum, bizarre mitodhoncria, and huge lipid inclusions, which are changes suggestive of disturbed function.

Animals↗
PubMed1975

Skeletal effects of cholesterol feeding.

The effect of a 4% supplement of cholesterol to a standard diet on knee joints and vertebral columns was investigated in male mice of strain C57B1. The experimental diet was fed from the time of weaning through the 18-month period of observation or from the age of 1 year to the end of the experiment at 18 months of age. The incidence of osteoarthrosis was increased in mice fed cholesterol from the age of 12 months on. The incidence of spondylosis was increased after lifelong feeding as well as after feeding of cholesterol during the second year of life. This increase involved both, spondylosis associated with or uncomplicated by prolapse of intervertebral discs. The incidence of simple disc prolapse was not affected by the experimental diet.

Animals↗
PubMed1975

Submicroscopic response of articular chondrocytes to a cholesterol-containing diet.

10 days' to 3 months' consumption of a diet containing 4% cholesterol causes a minor and transitory stimulation of articular chondrocytes of mice. The transitory disturbance is accompanied by a more permanent increase in glycogen, by abnormal deposition of cytoplasmic lipid and by an increase in the fibrillarity of the pericellular matrix. The changes are consistent with the failure of the cholesterol diet to influence the course of osteoarthrosis if fed to mice from an early age through life.

Animals↗
PubMed1975

Skeletal growth and development of achondroplastic mice.

Skeletal development of achondroplastic (cn/cn) mice, aged 2 to 7 weeks, was investigated and compared with that of equally old non-achondroplastic sibs. Differences in body weight and dry weight of femora, tibiae, humeri, and unlae, and in the length of tibiae, unlae, and humeri became more marked with advancing age. Of the biochemical assays carried out, only those for sialic acid and hydroxyproline disclosed significant differences between dwarfs and non-dwarfs, all dwarfs having higher levels of hydroxyproline, and most of them having higher sialic acid levels than the non-dwarfs. Histologically, no distinction could be made between growth zones of non-dwarfs, of cn/+, or +/+ genotype. Among the dwarfs, two groups differing as to the severity of the skeletal abnormality could be distinguished. The differences between dwarfs were most marked in the growth zones of tibiae and femora, less conspicuous in those of vertebrae and least pronounced at the chondro-osseous junction of the ribs. The cause or causes of the histologic heterogeneity remain unknown.

Achondroplasia↗