Prolongation of allograft survival by 1,25-dihydroxyvitamin D3

BACKGROUND: 1,25-Dihydroxyvitamin D3, the hormonal form of vitamin D, is now believed to play a significant role in the immune responses, both in vitro and in vivo, preventing the development of several autoimmune diseases. These studies suggest that 1,25-dihydroxyvitamin D3 may be effective in prolonging allograph survival. METHODS: To test the hypothesis that 1,25-dihydroxyvitamin D3 would prolong allograft survival, neonatal heart grafts were transplanted to allogeneic recipients receiving either 19-nor-1,25-dihydroxyvitamin D2 (200 ng/day) or 1,25-dihydroxyvitamin D3 (50 ng/mouse/day) orally through the diet. The efficacy of 1,25-dihydroxyvitamin D3 in prolonging graft survival in a vascularized model was determined by heterotopic ACI to Lewis heart transplants. RESULTS: The provision of exogenous 1,25-dihydroxyvitamin D3 or an analog, 19-nor-1,25-dihydroxyvitamin D2, to mice markedly prolonged the survival of neonatal mouse heart allografts. Similar results were obtained with a vascularized heterotopic heart transplant model in rats. Cyclosporine at a maximum 25 mg/kg dose for mice proved less effective than 1,25-dihydroxyvitamin D3. Graft survival in mice differing at class I and class II loci (B10.A(4R) --> C57BL/10) increased from 13.0+/-1.1 days to 51.0+/-5.6 days and was significantly better than cyclosporine monotherapy (33.2+/-3.6). Rat heart survival in a high responder strain combination (ACI --> Lewis) increased from 6.2+/-0.3 to 25.2+/-2.8 days. The increased survival of the transplants brought about with 1,25-dihydroxyvitamin D3 was not accompanied by hypercalcemia in rats. CONCLUSION: These results suggest that 1,25-dihydroxyvitamin D3 can be used as an effective agent in preventing graft rejection.     

Kinetics of decarburisation of levitating liquid iron drops by carbon dioxide

Decarburisation experiments were carried out by levitating liquid iron droplets in a flowing gas stream containing carbon dioxide at 1723K. Decarburisation of liquid iron droplets by carbon dioxide can be adequately described by the mixed control of gas phase mass transport and dissociative chemisorption of carbon dioxide. Carbon monoxide in the gas phase does not have any significant effect on the rate of decarburisation. The rate of decarburisation decreases significantly with increase in sulphur content in the melt and this effect can be quantitatively explained using the Langmuir isotherm. Adsorption coefficient of sulphur is found to be 200. Influence of phosphorus and chromium in the melt on the rate of decarburisation is negligibly small.     

The role of glycoproteins in neural development function, and disease

Glycoproteins play key roles in the development, structuring, and subsequent functioning of the nervous system. However, the complex glycosylation process is a critical component in the biosynthesis of CNS glycoproteins that may be susceptible to the actions of toxicological agents or may be altered by genetic defects. This review will provide an outline of the complexity of this glycosylation process and of some of the key neural glycoproteins that play particular roles in neural development and in synaptic plasticity in the mature CNS. Finally, the potential of glycoproteins as targets for CNS disorders will be discussed.     

Canine bladder cancer: epidemiologic features

Significantly reduced immunoglobulins were found in 22 patients with phenylketonuria. Tests of cellular immune function which included delayed skin hypersensitivity, T rosettes and PHA transformation were normal. Escherichia coli antibodies and the booster response to tetanus toxoid were also normal.     

Low temperature specific heat and magnetic study of precipitation in a Cu−Co alloy

Specific heat measurements between 1.4° and 4.2°K and magnetization measurements from 4.2° to 300°K with a Cu+0.7 at. pct Co alloy, solution treated at 1000°C and aged at 400°C, give the concentration and dipole moment of precipitated cobalt-rich particles as a function of aging time.     

Independent effects of acetic acid and pH on survival of Escherichia coli in simulated acidified pickle products

Our objective was to determine the effects of organic acids and pH on the rate at which selected strains of Escherichia coli O157:H7 die in acid solutions representative of acidified pickle products (pH < 4.6). We used gluconic acid/sodium gluconate (pKa = 3.7) as a noninhibitory buffer to maintain pH at selected values in the absence of other organic acids. This was possible because we found that the inhibitory effects of this acid on E. coli strains at pH 3.1 were independent of acid concentration over a range of 2 to 200 mM. By this method, the lethal effects of acetic acid solutions (100 to 400 mM) at selected pH values between 3.1 and 4.1 were compared with the effects of pH alone (as determined using gluconate buffer). We found D-values were two- to fourfold lower with acetic acid compared with the effect of pH alone for simulated pickle brines in this pH range. Glutamic acid, an amino acid that is known to enhance acid resistance in E. coli and is a component of pickle brines, protected the E. coli strains from the specific effects of acetic acid.     

Mobility of holes in the quaternary alloy In1?xGaxAsyP1?y

Hole mobilities have been measured at temperatures from 77 to 300 K in a wide range of quaternary alloys grown lattice-matched to InP substrates by liquid-phase epitaxy. Over most of the composition range the hole mobility at room temperature is lower than in InP itself, and is dominated by alloy scattering.     

Visualization of primate high density lipoproteins isolated by density gradient ultracentrifugation

High density lipoproteins (HDL) isolated by density gradient ultracentrifugation from the plasma of monkeys ingesting semipurified diets are barely visible. This creates difficulty in separating HDL from other lower density lipoproteins following centrifugation and necessitates collecting large quantities of background density solution to insure complete recovery of the HDL fraction. A simple procedure is described involving the addition of β-carotene to nonhuman primate plasma prior to centrifugation which results in the delineation of HDL as a discrete yellow-orange band without affecting certain physical properties of HDL or interfering with standard lipid and protein assays.