An analysis of the unconfined compression of articular cartilage

Analytical solutions have been obtained for the internal deformation and fluid-flow fields and the externally observable creep, stress relaxation, and constant strain-rate behaviors which occur during the unconfined compression of a cylindrical specimen of a fluid-filled, porous, elastic solid, such as articular cartilage, between smooth, impermeable plates. Instantaneously, the "biphasic" continuum deforms without change in volume and behaves like an incompressible elastic solid of the same shear modulus. Radial fluid flow then allows the internal fluid pressure to equilibrate with the external environment. The equilibrium response is controlled by the Young's modulus and Poisson's ratio of the solid matrix.     

Hematochemical parameters in sheep and goats of Sardinian breeds. II) Total blood cholesterol

It has been studied the total plasma cholesterol rate in lactating or dry sheep and goats of Sardinian breed. The values obtained for the four different groups of subjects have been compared with the "t of Student". While the difference between the sheep groups has seemed very accentuated, it has appeared hardly significant between the goat groups. Highly significant difference has also been found between lactating sheep and goats whereas there was no significant difference among the groups of dry subjects.     

Hydroxyl radical production in a purified NADPH--cytochrome c (P-450) reductase system.

Using the spin trap, 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) we have demonstrated that hydroxyl radicals are generated indirectly from purified preparations of rat liver microsomal NADPH-cytochrome c (P-450) reductase during NADPH oxidation. Hydroxyl radical formation is completely inhibited by p-chloromercuribenzoate, but not by metyrapone. In addition, hydroxyl radical DMPO adduct formation is blocked by added linolenic acid which, in turn, is peroxidatively degraded into malondialdehyde, suggesting that hydroxyl radicals formed from purified NADPH-cytochrome c (P-450) reductase are capable of initiating lipid peroxidation. A mechanism for the indirect production of hydroxyl radicals from NADPH-cytochrome P-450 reductase is discussed.     

Synthesis of the spin-labeled derivative of an ether-linked phospholipid possessing high antineoplastic activity.

We report here the complete synthesis of the spin-labeled derivative of an antitumor ether phospholipid, 1-O-octadecyl-2-O-(4'-doxylpentyl)-rac-glycerol-3-phosphocholine. This also represents the first time that the synthesis of a nitroxide spin-labeled diether phospholipid is described. In vitro experiments showed that at micromolar concentrations, this new analog is readily incorporated into the plasma membranes of human HL60 and mouse E8/AK.D1 leukemic cells, and subsequently kills the cells. The availability of this new probe should permit the electron spin resonance spectroscopic approach to investigate ways by which anti-tumor ether phospholipids selectively destroy the tumor cells.     

Retinal Gangliosides in RCS Mutant Rats

Abstract: The distribution of retinal gangliosides was studied in normal and mutant rats with retinal dystrophy at 30 and 180 days of age. The loss of photoreceptor cells in the retinal dystrophic RCS rats was not associated with a significant reduction in the relative distribution of any of the major retinal gangliosides. The loss of photoreceptors, however, caused a marked increase in total retinal ganglioside concentration. These findings suggest that photoreceptor cells contain a low concentration of gangliosides and that no major retinal ganglioside is localized or concentrated in these cells. The cellular localization and function of the most abundant retinal ganglioside, G_D3, is discussed.     

Distribution of bovine fetuin and albumin in plasma, allantoic and amniotic fluids during development

A radioimmunoassay for bovine fetuin was developed and its specificity and validity established. Albumin was measured by radial-immunodiffusion assay. Fetuin levels in fetal plasma increased from 10 to 15 mg/ml between 4 and 8 months of gestation; albumin levels remained higher than fetuin. Neonatal plasma fetuin levels rapidly declined during the first 14 days post partum, coincident with a marked reciprocal increase in albumin levels. In allantoic fluid fetuin and albumin concentrations reached a peak at 7 months but fetuin values were always higher. In amniotic fluid both proteins peaked at 8 months; albumin levels were similar to those in allantoic fluid but fetuin values remained consistently lower than those in allantoic fluid throughout gestation. Fetuin levels in maternal plasma declined from 0.7 to 0.4 mg/ml between 1 month and term. We conclude that (1) at term there is an abrupt change from fetuin synthesis to increased albumin synthesis by the neonatal liver; (2) fetuin appears to be preferentially accumulated in the allantois whereas albumin is equally concentrated in the allantois and amnion.     

Zoogeographical distribution of Southeast Asian freshwater Calanoida

This paper reviews the systematic status and geographical distribution of 30 odd species of freshwater calanoid copepods in Southeast Asia. Three regions are delineated based on the diversity and abundance of these organisms; Region I being the Southasiatic element, Region II the attenuated belt of copepods and Region III rich in endemic species. The implication of a north-south diminishing of copepod species to inland fisheries is postulated.     

Detection of virus-like particles in the coremia of Penicillium claviforme.

A double-stranded ribonucleic acid (dsRNA) was isolated from coremial extracts of wild type P. claviforme, by methylated-albumin kieselguhr chromatography. Differential centrifugations of the coremial extracts from WT and Sh mutant strains yielded two classes of virus-like particles (VLP), of dimensions 25-30 nm, and 50-70 nm. The possible ecological significance of fungal viruses is discussed.