Derepressed alloantigen in transplacentally induced lung tumor coded for by H-2 linked gene

A transplacentally induced lung tumor of strain C3Hf mice grows progressively when transplanted to (C3Hf X A)F1 hybrid mice but not when transplanted to C3Hf recipients. Progressive tumor growth occurs in [(C3Hf X A)F1 X C3Hf] backcross mice inheriting the H-2a haplotype from the F1 parent. Furthermore, radioresistant immunity to the lung tumor can be induced in C3Hf mice by immunization with normal tissue of B10.A and B10.A(2R) but not of B10 or B10.A(5R) strain mice.     

Energetics of triosephosphate isomerase: deuterium isotope effects in the enzyme-catalyzed reaction

The effect of isotopic substitution of the specifically labilized hydrogen in the substrates of triosephosphate isomerase on the steady-state rates of the enzyme-catalyzed reaction has been examined. The k cat value for the enzyme-catalyzed transformation of [1(R)-2H] dihydroxyacetone phosphate is 2.9 times smaller than that for the 1(R)-1H compound. Because of the rapid loss of 2H to solvent from the enzyme-enediol complex, this factor represents the full kinetic isotope effect of the proton abstraction step. The values of k cat and of Km for D-[2-2H]glyceraldehyde 3-phosphate are indistinguishable from those of the 2-1H material. This arises from the rapid loss of 2H from the enzyme-enediol intermediate, which results in 1H rather than 2H transfer in the rate-limiting step. The steady-state kinetic results reported in this paper qualitatively confirm and quantitatively extend the results from the previous papers on the variation of the free energy along the reaction path.     

Long-acting narcotic antagonist complexes

We evaluated the ability of close to 100 organic acids to form water-soluble salts with methadone, cyclazocine, naloxone, naltrexone and, more recently, diprenorphine. About half the acids yielded insoluble salts. Polybasic acids affording insoluble salts were evaluated for their ability to form drug:acid:metal complexes with the polyvalent metal ions, Zn++, Al+++, Mg++ and Ca++. Optimum conditions for forming complexes have been developed and the consistency of their composition has been established. Salts were analyzed spectrophotometrically for drug content, and complexes were analyzed for drug and metal content. The in vitro degree of dissociation at equilibrium was measured for the preparations suspended in a simulated physiological buffer, pH 7.3. Preparations of the narcotic antagonist drugs showing relatively low degrees of dissociation in vitro, since it early appeared that a high degree of dissociation contraindicated a prolonged duration of pharmacological action, were evaluated in mice after intramuscular administration at several dose levels by the mouse tail-flick test for the potency and duration of their morphine antagonist activity. Our most promising preparations to date, showing the most prolonged durations of action without evidence of gross toxicity, are naltrexone zinc tannate and naltrexone aluminum tannate. These are undergoing detailed evaluation as potential clinical candidates. Thus far, the most useful of several dosage forms studied is a suspension in an aluminum monostearate gel.     

Comparative structural and immunochemical properties of leghaemoglobins

Circular dichroism studies on leghaemoglobins from snake bean, lupin, serradella and other plants show that, in common with soybean (reported earlier) they have a similar overall polypeptide chain conformation and haem environment and orientation. Immunochemical studies, on the other hand, suggest that the antigenic determinants on the surface of the leghaemoglobins vary considerably. Thus, firstly the alpha-helix content of the leghaemoglobins as a class is very similar (60-65%) and approaches that of the myoglobins, secondly, the sign, magnitude and shape of their circular dichroism spectra in the near ultraviolet, Soret and visible regions suggest close similarities in the environment and orientation of a structurally important tryptophan residue and of the haem moiety, and thirdly, there is comparatively weak haem-protein interaction. The extent of immuno cross-reactivity was found to be best deomonstrated using the Farr radioimmunoassay procedure. The results were (a) 5 leghaemoglobins from one plant (soybean) crossreacted completely but with varying affinities. (b) The extent of cross reactivity between leghaemoglobins from different plants was compared to that within a single plant; the reaction of antiserum to a soybean leghaemoglobin with a serradella leghaemoglobin was weak, with a snake bean leghaemoglobin still weaker (and incomplete) while lupin leghaemoglobins showed no cross reactivity at all. (c) The "rapid" attenuation of cross reactivity among different plant leghaemoglobins is explicable in terms of the extensive amino acid substitutions which have been demonstrated in the literature and in the present studies. (d) In view of this rapid divergence it is not surprising that sperm whale and horse heart myoglobins showed no cross reactivity with soybean leghaemoglobins. In summary, amino acid substitutions in the leghaemoglobin family are conformationally but not immunochemically conservative.     

Cerebral ischemic events associated with prolapsing mitral valve

Twelve patients who had no evidence of arteriosclerotic cerebral vascular disease, lacked hypertension or coagulation defect, and had not been receiving contraceptive therapy had recurrent transient cerebral ischemic attacks (TIAs) and partial nonprogressive strokes. All had prolapsing mitral valve proved by angiocardiography. The average age was 38 years, compared with 62 years in a larger series of patients with TIA associated with arteriosclerosis. We propose that the ischemic events are related to emboli emanating from the abnormal mitral valve with or without an associated paroxysmal cardiac arrhythmia.     

Acute pyelonephritis simulating poorly vascularized renal neoplasm. Non-specificity of angiographic criteria

A case of acute pyelonephritis associated with venous encasement and amputation is described. Although venous encasement and amputation have been considered previously as specific signs of malignancy, it is now clear that these signs are non-specific, occurring also in inflammatory diseases of the kidney.     

Isolation of Vibrio parahaemolyticus from fecal specimens on mannitol salt agar

Kittens of 25 and 50 days of age were tested on a passive avoidance task in a 2-compartment black-white shuttle box. Latency to enter the dark side of the box was the same for both groups on Day 1, but the latency to enter the dark side on Day 2 was much shorter for the younger kittens. Other kittens were trained in a step-up active avoidance task also at 25 and 50 days of age. No differences were found in active avoidance performance between the younger and older animals, indicating that active and passive avoidance tasks may possibly reflect separate developmental processes that mature at different rates in the cat.