Lymphoid cell subclasses in rejecting renal allograft in the rat

We have quantitated the frequency of lymphoid cell subsets in rejecting renal allografts and in the spleen of the allograft recipient during drug-unmodified rejection in the rat. The number of inflammatory (white) cells in the graft was approximately similar to the number of white cells responding to the allograft in the recipient spleen. The inflammatory population of the graft consisted of lymphoid cells and mononuclear phagocytes, with increasing numbers of macrophages toward the end of rejection. Analysis of allograft cellular dispersates with monoclonal antibodies directed to the lymphoid cell subsets demonstrated that although the majority of allograft-infiltrating lymphocytes were T cells, a sizable B-cell proliferation and immunoglobulin synthesis was associated with the inflammatory response of rejection. Within the T-cell subset, the T suppressor/killer cells predominated in the graft whereas the predominant lymphoid cell subset responding to the allograft in the recipient spleen was the T helper cell.     

Suppression of natural killer activity in human blood and bone marrow cultures by bone marrow-adherent OKM1-positive cells

Maintenance and regulation of natural killer (NK) cell activity in human bone marrow cultures were studied using K562 leukemia cells as targets. Culture of bone marrow cells in medium supporting long-term generation of myeloid cells resulted in a rapid loss of NK activity in 1-3 days. In contrast, antibody-dependent cytotoxicity to an NK-resistant tumor was maintained for more than 7 weeks. Horse serum, a component of the myelopoietic culture medium, was found to diminish NK cytotoxicity of blood and bone marrow cultures whereas hydrocortisone supplement did not. In addition, an adherent cell is present in bone marrow which greatly inhibits NK activity. Nonadherent bone marrow cells exhibited higher cytotoxicity than unfractionated cells at all days of culture; adherent cells were not cytotoxic to K562. Purified adherent marrow cells inhibited the cytotoxic capacity of nonadherent blood or marrow mononuclear cells during coculture. Indomethacin, an inhibitor of protaglandin synthesis, augmented levels of NK activity in cultures of bone marrow cells, indicating that macrophages may be suppressing this effector function via prostaglandins. Further identification of the adherent suppressor cells came from experiments in which suppression was prevented by treatment of the adherent cells with monoclonal OKM1 antibody plus complement. This study shows that bone marrow-adherent OKM1-positive cells, presumably macrophages, negatively regulate NK activity, and it defines conditions for analysis of the generation and/or positive regulation of NK cells in human bone marrow.     

Rabbit kidney function in vitro: the effect of colloids, energy substrate, a vasodilator, perfusion pressure, and bovine serum albumin

An in vitro perfusion system at 37 degrees C for the assessment of rabbit kidney function is described. The purpose of this assay system is to evaluate the effects of cryobiological manipulation on kidney function. The effect of the colloids dextran (MW = 70,000, 80,000, and 180,000) in the perfusate at 110 mm Hg were compared to a reduced perfusion pressure, colloid-free perfusate. Better function was obtained at lower perfusion pressure with the colloid-free perfusate. Less damage was noted histologically on light and electron microscopy. Investigation of energy substrates on rabbit kidney function demonstrated that butyrate, or lactate, in addition to glucose resulted in increased sodium and glucose reabsorption over glucose alone. Substrate-free perfused kidneys exhibited depressed Na transport. Lactate, and to some extent butyrate, decreased net glucose utilization. An alpha-adrenergic blocking agent, isoxsuprine, in the initial flush solution did not appear to be beneficial. An increase of perfusion pressure from 50 to 75 mm Hg resulted in an increase in GFR. Tubular function was enhanced by inclusion of small amounts of BSA in the perfusate.     

Panagrellus ceylonensis n. sp. (Nematoda: Cephalobidae)

Panagrellus ceylonensis n. sp. is described from rubber latex in Ceylon. Its long, slender spicules are curved ventrally with a dorsal deflection at two-thirds of their length. The manubrium is thick and hooked, and the shaft is not widened at the shoulder. The terminal bifurcations are wide, with the dorsal one considerably longer and thicker than the ventral. The main ventral element is continuous with the terminal sheath with the ventral bifurcation arising within it.     

Apparent unbalance between the activities of 6-phosphogluconate and glucose-6-phosphate dehydrogenases in rat liver

The ratio of activities of 6-phosphogluconate dehydrogenase/glucose-6-phosphate dehydrogenase measured in liver extracts of rats in lipogenic nutritional conditions is only 0.2, suggesting an apparent physiological unbalance between the two dehydrogenases of the hexosemonophosphate shunt. This potential unbalance is enhanced by the fact that TPNH is a more powerful competitive inhibitor of 6-phosphogluconate dehydrogenase than of glucose-6-phosphate dehydrogenase. Accordingly, a strong activation of 6-phosphogluconate dehydrogenase would be required for efficient functioning of this pathway, unless there is an alternative outlet for 6-phosphogluconate so far unrecognized in animal tissues.     

Synchronization of Mating Reactivity Rhythms in Populations of Paramecium bursaria

Cell populations of Paramecium bursaria show arhythmic mating reactivity after exposure to constant light (LL) for more than 2 wk. After this arhythmic population is exposed to darkness for 9 h, the mating reactivity rhythm of the cell population reappears. The phases of rhythms in individual cells are synchronized to each other. When the arhythmic population in constant light is exposed to dark pulses of various durations, the first peak of the recovered mating reactivity rhythm appears 6 h after the end of the dark pulse. Thus, in the case of dark pulses to cells in LL, the transition from dark to light sets the phase of the subsequent mating reactivity rhythm. When an arhythmic population in LL is transferred to constant darkness (DD), a rhythm of mating reactivity also appears and, in this case, the first peak of the rhythm occurs 18 h after the LL to DD transition. Therefore, arhythmic populations of cells in LL can be synchronized by either a dark pulse or by transition to continuous darkness. When the arhythmic populations in LL were transferred to various light/dark (LD) cycles, the mating reactivity rhythms entrained to LD cycles of 18 to 30 h in duration. Finally, mating rhythms can also be synchronized by treatment with puromycin (400 μg/ml for 6–18 h).     

黑腹果蝇P转座因子研究 Ⅰ.我国黑腹果蝇的P-M测定及其地理分布

采用性腺败育(GD不育)作为标准检定方法。对我国20个地方的黑腹果蝇的P因子活性和细胞型进行了测定。结果表明我国北部沿海城市为Q型;南部沿海和内地皆为M型。各地的M品系所产生的GD不育能力各不相同,但表现出与地理位置相关的梯度变化。这一变化规律为研究我国黑腹果蝇的P因子起源及P和M品系的形成提供了重要的理论依据。     

Vanadate-stimulated oxidation of NAD(P)H

Vanadate stimulates the oxidation of NAD(P)H by biological membranes because such membranes contain NAD(P)H oxidases which are capable of reducing dioxygen to O₂⁻ and because vanadate catalyzes the oxidation of NAD(P)H by O₂⁻, by a free radical chain mechanism. Dihydropyridines, such as reduced nicotinamide mononucleotide (NMNH), which are not substrates for membrane-associated NAD(P)H oxidases, are not oxidized by membranes plus vanadate unless NAD(P)H is present to serve as a source of O₂⁻. When [NMNH] greatly exceeds [NAD(P)H], in such reaction mixtures, one can observe the oxidation of many molecules of NMNH per NAD(P)H consumed. This reflects the chain length of the free radical chain mechanism. We have discussed the mechanism and significance of this process and have tried to clarify the pertinent but confusing literature.     

The reaction to c-banding of c-banded constituents during mitotic cycle ofCrepis capillaris

The reaction to C-banding was investigated throughout the mitotic cycle ofCrepis capillaris (2n=6): (1) 18–22 C-bodies or C-bands were found during mid telophase and interphase to prophase and metaphase, and also 12–14 at late anaphase to early telophase in the mitotic cycle. Fewer C-bands in late anaphase to early telophase were due to the absence of minute bands; (2) large and medium sized C-bands were strongly stained by Giemsa, while small and minute bands stained palely. It is suggested that inCrepis capillaris the difference of color in C-banded segments following Giemsa staining is referable to the amount of constitutive heterochromatin rather than to the difference in the condensation and decondensation; (3) the size of C-bodies changed during telophase to interphase and prophase. It is inferred that the extent of C-bodies is regulated by both the length of DNA sequences of constitutive heterochromatin and the amount of proteins combined with C-banded DNA. It was shown that the reaction to C-banding is neither due to the differential condensation of chromatin nor to a higher concentration of DNA in the C-banded regions, in the C-banding mechanism as has been suggested so far at least.     

Monoclonal Antibodies Allow Precipitation of Esterasic but Not Peptidasic Activities Associated with Butyrylcholinesterase

Commercially available and affinity-purified butyrylcholinesterases isolated from human serum were examined for their esterasic activity and their ability to hydrolyze various neuropeptides, including neurotensin, substance P, and leucine-enkephalin. The three pools that displayed the lowest esterasic activities were shown to hydrolyze neurotensin with the same HPLC degradative pattern. By contrast, noticeable qualitative and quantitative discrepancies were observed when hydrolyses of substance P and leucine-enkephalin by these three butyrylcholinesterase pools were studied. The pool that exhibited the highest esterasic activity appeared to be homogeneously constituted by 90- and 180-kDa protein bands by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and was totally unable to hydrolyze these three neuropeptides. This suggested that the three other butyrylcholinesterase preparations could be contaminated by exogenous peptidases. This was confirmed by means of three distinct monoclonal antibodies directed toward human serum butyrylcholinesterase. The three IgG-purified fractions precipitated the esterasic activity, whereas they failed to precipitate the neuropeptide-hydrolyzing activities whatever the substrate examined. Altogether, these results demonstrate that peptidases associated with butyrylcholinesterase are contaminating enzymes that cannot be considered as intrinsic activities of this enzyme.