Diamide inhibits pulmonary vasoconstriction induced by hypoxia or prostaglandin F2 alpha

Diamide oxidizes glutathione and other cellular sulfhydryl groups. It decreases calcium ATPase activity and alters mitochondrial calcium flux, probably as a result of the sulfhydryl oxidation. We examined the effect of diamide (5 mg/kg, iv) on pulmonary vascular reactivity in 12 anesthetized dogs. Diamide reversed the pulmonary vasoconstriction caused by hypoxia in seven dogs (control delta PVR + 2.5 +/- 0.6 mm Hg/liter/min; postdiamide delta PVR - 0.1 +/- 0.4 mm Hg/liter/min; P less than 0.01). The pulmonary pressor response to prostaglandin F2 alpha (5 micrograms/kg/min, iv) was also reduced (control delta PVR + 3.8 +/- 0.5 mm Hg/liter/min; postdiamide delta PVR + 1.1 +/- 0.7 mm Hg/liter/min; P less than 0.01). However, in a further five dogs, diamide had only a small effect on the pulmonary vasoconstriction caused by angiotensin II, while the pressor response to hypoxia was again inhibited. The mechanism by which diamide reverses pulmonary vasoconstriction is not certain but the effect is rapid, consistent, and reversible. Because the intravenous infusion of diamide does not produce systemic hypotension, during its period of action on the pulmonary vasculature, unlike the drugs currently available for the clinical treatment of pulmonary hypertension, further studies of its mechanism of action are indicated.     

Linkage between a marker locus and a quantitative trait of sibs

Several variations of a method for detecting linkage between a marker locus and a quantitative trait in full sib families are presented along with computational details. All variations are based on contrasts within qualifying families of three or more sibs. The empirical powers of the various test statistics, evaluated by simulation, were very similar, and also similar to that of Smith. These single-generation tests are likely to be successful only for many families and relatively tight linkage.     

Chromosome studies in some members of the family Caviidae (Mammalia: Rodentia)

A study of the chromosomes of Cavia aperea and Galea musteloides has been made following the introduction into captivity of these two cavies from Argentina. The evolutionary relationships of the two genera have been considered, and the possible ancestry of C. porcellus from C. aperea was investigated in hybrids of the two species.     

Behavior of pairs of loci in finite monoecious populations

Transition equations are established for descent measures for pairs of loci in finite randomly mating monoecious populations. The two special cases of equal chance gamete formation and two gametes per parent are considered in detail. The descent measures allow genotypic frequencies to be found but are used mainly to evaluate three quadrigenic moments, including the variance of the linkage disequilibrium. Numerical properties of these moments are compared to previously reported values.     

Computer-assisted Follow-up Register for the North-East of Scotland

An automated follow-up register for the detection of iatrogenic thyroid disease has been established as a joint venture between the general practitioners in the north-east of Scotland and the thyroid clinic of Aberdeen General Hospitals.The data-processing operations in the system are handled by an International Computers Limited 4/50 computer. Patients are followed up at predetermined intervals and the system has been designed to process, screen, and store clinical and biochemical follow-up data and report results to the patients, general practitioners, and the hospital records department.     

Comparison of the structure of the immunoglobulins from horse serum

A study of the chemical structure of the horse immunoglobulins IgG and IgA(T) has shown that the amino acid contents of the peptide chains are very similar. These globulins differ most markedly in the products of papain digestion. IgG gives 3.5s products, whereas IgA(T) gives a 5s fraction and smaller components. This difference appears to be associated with the presence of an additional easily reducible disulphide bond in the Fd fragment of the heavy chain. There is two to three times as much carbohydrate in IgA(T) as in IgG. In both, this is in the heavy chain and in IgA(T) more than half is covalently bound to the Fd fragment. The differences in antigenic specificity between horse IgG and IgA(T) appear to be due to structural differences in the Fc fragment.     

The search for new industrial crops

Advances in technological development have produced an ever-increasing pressure for new and different raw materials to keep pace with changing industrial needs. Many new and useful properties of plants may be discovered through the modern chemistry and technology of utilization research. The U. S. Department of Agriculture’s search for new industrial crops is a coordinated botanical and utilization research program.