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Biomedical subjects

L Sokoloff

Publications and source records attributed to L Sokoloff.

At least 253 records · Page 14Linked to original sources
PubMed1978

Technical note: an improved McCutchen miniviscometer for connective tissue fluids.

McCutchen's miniviscometer is a Couette-type instrument that requires only 0.2 ml of synovial or other test fluid. The modification described here adds to the capabilities of the original: control of temperature good to +/- 0.2 degrees C; increase of the maximum measureable viscosity at low shear rates (20 sec-1) to 3000 centipoise; and expansion of the usable range of shear rates to (20--1500 sec-1. The device is rugged and data are reproducible to +/- 1.2% (S.D.) of the mean over the full range of shear rates.

Body Fluids↗
PubMed1978

Explant culture of human and rabbit articular chondrocytes.

Copious outgrowth of chondrocytes was obtained by explantation from each of three rabbit and one surgically-resected human articular cartilages pretreated briefly with trypsin. In lapine explants, ascorbate (40 micrograms/ml) increased DNA three-fold over control values and resulted in deposition of a chondroid matrix. It doubled radiosulfate incorporation by the outgrowths. Up to 56% of the sulfated glycosaminoglycan synthesized was located in the trypsin-digestible pericellular coat compared with about 15% in previous monolayer cultures. The collagens synthesized were characterized partially. In rabbit cell cultures, the alpha 1:alpha 2 ratio varied from 2.9 to 3.8. In human cultures, an unusual post-alpha 2 peak was observed. The findings suggest an uncoupling of the phenotypic expression of the major cartilaginous macromolecules in the cultures. There were no distinctive differences between chondrocytes derived from normal and fibrillated human cartilage of the same individual.

Animals↗
PubMed1977

Species differences in cell culture of mammalian articular chondrocytes.

Articular chondrocytes from eight mammalian species (rabbit, opossum, woodchuck, cat, dog, sheep, rhesus and cebus monkeys) were grown in monolayer culture using a single regimen. The animals were immature or young adults. Ham's F12 medium supplemented with 10% fetal bovine serum was employed for the primary cultures and Dulbecco-Vogt medium, for the secondary. Marked species differences were found with respect to cell morphology, growth in primary and secondary cultures, incorporation of radiosulfate into macromolecules, adhesion to the flask surface, response to vitamin C, and chondroid expression in spinner bottles. Under these particular conditions, rabbit chondrocytes grew most rapidly and incorporated several times more sulfate than did the others. Additional experiments carried out with other media on four of the species indicate that optimal conditions for culturing mammalian chondrocytes must be determined for each species individually.

Animals↗
PubMed1977

Differences in the collagen types synthesized by lapine articular chondrocytes in spinner and monolayer culture.

In five different secondary monolayer cultures of rabbit articular chondrocytes, 72-89% of the the collagen synthesized was Type 1, as determined by alpha chain separation and CNBr-cleavage peptide analysis. When sister cells were transferred to spinner bottles after primary monolayer culture growth, 88% of the collagen formed in four separate experiments was Type II. A reversion to Type I collagen synthesis occurred when the spinner-cultured cells were returned to monolayer flasks. The change in the species of collagen depended on the suspension condition and not on the low Ca2+ content (0.33 mM) of the spinner medium. These findings parallel the switch to phenotypic glycosaminoglycan synthesis that also occurs when monolayer-cultured cells are transferred to spinner bottles. Whether this phenomenon arises through a genetic control mechanism rather than environmental selection for particular cohorts of cells has not yet been determined.

Animals↗
PubMed1977

The effect of prostaglandins of cultured lapine articular chondrocytes.

The effect of B protaglandins (PG) on growth and sulfate incorportation by monolayer and spinner-cultured rabbit articular chondrocytes has been measured. PGA1, PGB1, PGE1 and PGE2 reduced synthesis of sulfated glycosaminoglycans (GAG) but the PGF series did not. PGA1 was the most potent, being effective at a concentration of 2.5 microng/ml [6.8 micronM] while the others required 25 microng/ml. These compounds had no effect on degradation of GAG. All 8 PGs augmented growth slightly but significantly at 2.5 microng/ml. At the higher concentration, PGA1 was highly cytotoxic, and PGB1 as well as PGE2 reduced cell growth. The cytotoxicity of PGA1 was also observed in two additional types of cultured connective tissue cells, but the inhibition of sulfated-GAG synthesis by PGA1 and PGB1 was confined to the chondrocytes. The response of cultured chondrocytes to exogenous PGs, albeit at apparently unphysiologically high concentrations, together with other evidence, suggests that these compounds may conceivably play a direct role in cartilage metabolism in vivo.

Animals↗
PubMed1976

Identiy of brain alcohol dehydrogenase with liver alcohol dehydrogenase.

A method for obtaining electrophoretically homogeneous rat liver alcohol dehydrogenase (EC 1.1.1.1) at a specific activity of 2-2.5 mumol/min per mg of protein is presented. Anti-sera prepared against the purified enzyme inhibit alcohol dehydrogenase by up to 75% and cause precipitation of virtually all the enzyme. The antisera were shown by immunoelectrophoresis of a partially purified liver homogenate to be specifically directed against alcohol dehydrogenase and were used to demonstrate that the alcohol dehydrogenases of rat brain and liver share common antigens. The total activity of alcohol dehydrogenase in rat brain homogenates is normally quite low, with as much as 10% of the total activity attributable to the activity in the blood contained within the brain; in cases of severe liver damage (induced experimentally with carbon tetrachloride) this contribution may rise to as much as 60%.

Alcohol Oxidoreductases↗
PubMed1976

Metabolic anatomy of focal motor seizures.

Contralateral focal seizures occurred in rats following the intracortical injection of penicillin into the anterior motor cortex. The anatomic dimensions of the metabolic response in the focus as well as the spread of increased activity through the brain were studied by autoradiography following intravenous injection of carbon 14-labeled 2-deoxyglucose. Injections of 25 to 200 units of penicillin resulted in mild to severe contralateral motor jerks coincident with repetitive single spike discharges on the electroencephalogram. Concurrent autoradiography revealed a 1.3- to 2.5-fold increase in metabolic activity in discrete areas in ipsilateral cortex, basal ganglia, thalamus, and contralateral cerebellum. Intracortical injections of over 300 units resulted in the development of recurrent contralateral tonic-clonic seizures, with 20% becoming bilateral. In brains of these animals there was activation of bilateral medial frontal cortex, bilateral extrapyramidal system, thalamus, cerebellum, and limbic structures.

Amygdala↗
PubMed1976

Metabolic mapping of the primary visual system of the monkey by means of the autoradiographic [14C]deoxyglucose technique.

An autoradiographic technique that employs 2-[14-C]deoxyglucose to measure the local rates of glucose utilization within the brain has been applied to the binocular visual system of the Macaque monkey. This method, which pictorially displays the relative rates of glucose consumption in the component structures of the brain, delineates the regions of altered functional activity because of the close relationship between functional activity and energy metabolism. Bilateral retinal stimulation results in the delineation of different rates of glucose consumption in at least four cytoarchitectural layers of the striate cortex. The most intense metabolic activity appears to be in Layer IV, the locus of the termination of the geniculocortical pathway. Bilateral visual occlusion lowers the rates of glucoes consumption in striate cortex and markedly reduces the metabolic differentiation of the various layers. Unilateral visual deprivation delineates the laminae of the lateral geniculate body and the ocular dominance columns of the striate cortex. It also results in the autoradiographic visualization of regions with normally monocular input in the striate cortex, such as the rostral portions of the mushroom-like configurations in the calcarine cortex, which represent the extreme temporal crescents of the visual fields, and small regions in the most caudal part of the mushroom configurations, which are believed to represent the cortical loci of the blind spotsof the visual fields.

Animals↗
PubMed1976

Cartilage in hemophilic arthropathy. Ultrastructural and microanalytical studies.

The presence of iron in articular cartilage was investigated in five human and two canine cases of factor VIII-deficiency hemophilic arthropathy. The lesions were mild in three cases. Advanced destruction of the cartilage was present in four cases, in one of which sufficient cartilage was preserved to permit recognition of hemosiderin in chondrocytes. The Fe was present in the form of siderosomes and ferritin granules free in the cytoplasm. Iron and phosphorus were demonstrated in the siderosomes by energy dispersion analysis of x-rays; but no Fe was identified by this means or by light or transmission electron microscopy in chondrocytes from the three subjects in an early stage of the disease or in the matrix from any of the seven subjects. The findings lend no support to the hypothesis that salt formation or chelation of Fe ions by matrix proteoglycans is responsible for destruction of cartilage in hemophilic or other chronic hemarthroses. A second, nonferruginous, bilirubin-like pigment (hematoidin) was present in the matrix at the surface of the cartilage in two specimens.

Adult↗