Boundary lubricating ability of synovial fluid in degenerative joint disease

The boundary lubricating ability of eleven synovial fluids was measured in a miniaturized latex--glass test system. The specimens were obtained at necropsy from knees in which the degree of degenerative joint disease varied from none to very severe. The lubricating ability of the fluid was independent of the viscosity over a wide range of shear rates. It was not diminished even in advanced lesions. In two additional fluids, the mucin clot was poor; the lubricating ability of one of these was compromised. Thus, although degenerative joint disease, during its quiescent stages, is not associated with defective synovial lubrication, the possibility that transient defects might lead to cartilage wear during life has not been excluded. The measurements are believed to be valid indicators of boundary lubricating ability under physiological conditions despite the fact that the test surfaces were not cartilaginous and the loading was relatively low (up to 47 pounds per square inch).

Functional plasticity in the immature striate cortex of the monkey shown by the [14C]deoxyglucose method

Autoradiographic representation of the local rates of cerebral glucose utilization and local cerebral functional activity by means of the [14C]deoxyglucose technique reveals the existence of the ocular dominance columns in the striate cortex of the monkey in the first day of life. In contrast to the stability of these columns in more mature brain, monocular deprivation for 3 months from the first day of life results in their complete disappearance and a reversion of the autoradiographic pattern to that seen in animals with normal binocular vision. These results are consistent with a reorganization of the representation of the visual fields of the two eyes in the striate cortex and provide additional evidence of the plasticity of the striate cortex of the monkey in early life.

Local cerebral energy metabolism: its relationships to local functional activity and blood flow

The results of studies with the [14C] deoxyglucose technique unequivocally establish that local functional activity in cerebral tissues is, as in other tissues, closely coupled to the local rate of energy metabolism. Stimulation of local functional activity increases the local rate of glucose utilization; reduced functional activity depresses it. Local cerebral blood flow is normally distributed among the cerebral structures in almost exact proportion to their rates of glucose utilization and it changes together with local glucose consumption in response to altered local functional activity. These results demonstrate that the level of functional activity in the structural and functional components of the central nervous system regulates the local rate of energy metabolism, and local blood flow is adjusted to the local metabolic demand.

Occult osteomalacia in American (U.S.A.) patients with fracture of the hip

Low-grade osteomalacia, detectable only by quantitative histological measurement, was present in eight of 31 femoral heads from normocalcemia American patients having intracapsular fracture of the hip. The histological changes were of a much lower degree than those observed in overt clinical osteomalacia. Further, regional differences between the osteoid content of the proximal femur and iliac crest were demonstrated in 13 age-matched controls. In these, the osteoid content of the femoral bone averaged only 30% of that in the iliac crest.

Local cerebral glucose uptake in awake and halothane-anesthetized primates

Local glucose consumption within specific brain structures in awake and halothane-anesthetized primates was studied using a quantitative autoradiographic technique for glucose (14C-deoxyglucose). In both awake and anesthetized animals, significant heterogeneity (one-way analysis of variance) in uptake of glucose was found in the cortex, subcortical grey matter, and brainstem nuclei. No significant variability was found for any of the white matter areas sampled under either experimental condition. Halothane produced significant decreases in glucose metabolic rates in the occipital cortex, brainstem nuclei, cerebellar cortex, cerebellar white matter, and anterior commissure, compared with the awake state. The greatest decrease in cerebral metabolic rate was found in the occipital lobes of halothaneanesthetized animals. Results of this study suggest that neurophysiologic and behavioral changes that occur with anesthetic agents can, for the first time, be correlated with alterations in local cerebral glucose metabolism.

Measurement of local cerebral blood flow with iodo [14C] antipyrine

The autoradiographic diffusible tracer technique for the measurement of local cerebral blood flow was originally designed for use with the radioactive, inert gas 131I-labeled trifluoroiodomethane and is applicable only with tracers that exhibit unrestricted diffusion through the blood-brain barrier. Because of the technical problems associated with the use of gaseous tracers, a suitable nonvolatile tracer has been sought. [14C] Antipyrine has been used previously and found to be unsuitable because of limitations in its diffusion through the blood-brain barrier. An analogue of [14C]antipyrine, iodo [14C]antipyrine, exhibits higher partition coefficients than [14C]antipyrine between nonpolar solvents and water and might, therefore, be expected to diffuse more freely through the barrier. Its use as the tracer in the local blood flow technique leads to values considerably above those obtained with [14C]antipyrine in the rat and cat and essentially the same as those obtained with the gas trifluoro[131I]iodomethane in the cat. Iodo[14C]antipyrine appears, therefore, to be a satisfactory nonvolatile tracer for the measurement of local cerebral blood flow.

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.

The effect of chondrocyte growth factor on membrane transport by articular chondrocytes in monolayer culture

Chondrocyte growth factor (CGF), a contaminant of pituitary glycoprotein hormones, stimulates growth of cultured lapine articular chondrocytes while depressing SO4-proteoglycan synthesis. To study its effect on membrane transport, NIH-bTSH and two other preparations with comparable CGF activity were employed. In early log phase (36 hr) cultures CGF (64 microgram/ml) did not alter thymidine (dThd) uptake during the first 5 min. By 15 min however, TCA-precipitable dThd was 4-fold greater than in controls while the TCA-soluble fraction remained the same. CGF increased deoxy-glucose (DG) uptake in 36-hr old cultures. At 66 hr, CGF reduced DG transport. The transport of cycloleucine (CL) and aminoisobutyric acid (AIB) was reduced by CGF in 36 and 66-hr old cultures. There was a dose dependency between CGF concentration, the lowered uptake of DG, CL and AIB, and cell protein content. The effect of CGF on DG transport and dThd incorporation into DNA was not immediate but required prior exposure of the cells to CGF. CGF did not alter DG transport in rabbit or mouse fibrocytes or Chang liver cells. This and the reported finding that pituitary fibroblast growth factor (FGF), increases amino acid transport in other cells suggests that the biological specificity of CGF may not be identical to that of FGF.

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.

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.

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.

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.

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.

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.