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41.
42.
J Iwamoto M Yoshinaga S P Yang E Krasney J Krasney 《Journal of applied physiology》1992,73(6):2226-2232
Cerebral vasodilation in hypoxia may involve endothelium-derived relaxing factor-nitric oxide. Methylene blue (MB), an in vitro inhibitor of soluble guanylate cyclase, was injected intravenously into six adult ewes instrumented chronically with left ventricular, aortic, and sagittal sinus catheters. In normoxia, MB (0.5 mg/kg) did not alter cerebral blood flow (CBF, measured with 15-microns radiolabeled microspheres), cerebral O2 uptake, mean arterial pressure (MAP), heart rate, cerebral lactate release, or cerebral O2 extraction fraction (OEF). After 1 h of normobaric poikilocapnic hypoxia (arterial PO2 40 Torr, arterial O2 saturation 50%), CBF increased from 51 +/- 5.8 to 142 +/- 18.8 ml.min-1 x 100 g-1, cerebral O2 uptake from 3.5 +/- 0.25 to 4.7 +/- 0.41 ml.min-1 x 100 g-1, cerebral lactate release from 2 +/- 10 to 100 +/- 50 mumol.min- x 100 g-1, and heart rate from 107 +/- 5 to 155 +/- 9 beats/min (P < 0.01). MAP and OEF were unchanged from 91 +/- 3 mmHg and 48 +/- 4%, respectively. In hypoxia, 30 min after MB (0.5 mg/kg), CBF declined to 79.3 +/- 11.7 ml.min-1 x 100 g-1 (P < 0.01), brain O2 uptake (4.3 +/- 0.9 ml.min-1 x 100 g-1) and heart rate (133 +/- 9 beats/min) remained elevated, cerebral lactate release became negative (-155 +/- 60 mumol.min-1 x 100 g-1, P < 0.01), OEF increased to 57 +/- 3% (P < 0.01), and MAP (93 +/- 5 mmHg) was unchanged. The sheep became behaviorally depressed, probably because of global cerebral ischemia. These results may be related to interference with a guanylate cyclase-dependent mechanism.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
43.
On the basis of previous data that 1,25(OH)2D3 suppressed both helper and suppressor activities of CD4 and CD8 cells in the pokeweek mitogen-stimulated culture, we examined the further effect of 1,25(OH)2D3 on both cells to define how 1,25(OH)2D3 is involved in the deterioration of their functions. 1,25(OH)2D3 suppressed the pokeweed mitogen and phytohemagglutinin-induced DNA synthesis of CD4 and CD8 cells. The suppression by 1,25(OH)2D3 of DNA synthesis was caused by a time lag in reaching maximal response. 1,25(OH)2D3 also suppressed interleukin-2 production of CD4 and CD8 cells. 1,25(OH)2D3 did not, however, affect their interleukin-2 receptor expression detected within 24 hr after phytohemagglutinin stimulation. In addition, 1,25(OH)2D3 failed to suppress DNA synthesis of CD4 and CD8 cells when cultured with a large amount of interleukin-2. Suppression by 1,25(OH)2D3 of proliferation and interleukin-2 production in CD4 and CD8 cells would bring about the decrease of their helper or suppressor functions by inhibiting their expansion or maturation. 相似文献
44.
M-phase and S-phase protoplasts were prepared from tobacco cells in suspension culture after a high degree of synchronization using aphidicolin, a specific inhibitor for eukaryotic DNA polymerase. When TMV-RNA was introduced into these protoplasts mediated by REV liposomes, 37% of M-phase and 26% of S-phase protoplasts were infected as determined by the fluorescent antibody technique. After the 24 hr interval between the introduction of TMV-RNA into protoplasts and the determination of infection, half of the infected mitotic protoplasts formed dumbell-shaped daughter cells. The significance of synchronized protoplasts in genetic engineering of plant cells is discussed in reference to the delivery of DNA into the nucleus.Abbreviation LS
medium, Linsmaier and Skoog medium
- PEG
polyethylene glycol
- REV
reversephase evaporation vesicles
- TMV
tobacco mosaic virus 相似文献
45.
Kunihiko Kimura Yutaka Takahashi Masayoshi Konishi Sotaro Iwamoto 《Primates; journal of primatology》1981,22(1):119-130
On the basis of 44 hindlimbs of 14 male and 14 female crab-eating monkeys (Macaca fascicularis), the morphology of the adductor muscles of the thigh was described and some functional indices were calculated. The results
obtained from this study agreed generally with those of otherMacaca species reported by various authors. For the classification and nomenclature of the adductors, the criteria proposed byUhlmann (1967, 1968) was well adapted to the crab-eating monkey. The adductors comprise the m. gracilis, m. pectineus, m. adductor
longus, pars longa and pars brevis of m. adductor brevis, pars lata and pars minima of m. adductor magnus and m. obturatorius
externus. In males, the adductors are generally inserted further down the femur, and the insertions of pars brevis of the
m. adductor brevis and pars minima of the m. adductor magnus have longer attachments to the femur than in females. The arrangement
of each adductor muscle and of each fasciculus of a thigh muscle may invoke a principle of organization. 相似文献
46.
47.
The rôle of the midgut, crop, and maxillae in the production and utilization of the cocoon-digesting enzyme was investigated in the silkworm, Bombyx mori.About a sixtyfold purified preparation of midgut protease was obtained by ammonium sulphate precipitation and column chromatography.Immunological studies by the agar diffusion method of Ouchterlony revealed that the crop and midgut proteases of the pharate adult are antigenically identical whereas that of the maxillary protease is different.From the results of extirpation experiments and previous studies it was shown that the midgut, crop, and maxillae play important rôles in the escape of moths from their cocoons. 相似文献
48.
Summary Chimaeric genes containing the chloramphenicol acetyltransferase (CAT) coding sequence were introduced into protoplasts of suspension-cultured tobacco cells using improved conditions of electroporation (Okada et al. 1986). CAT activity became detectable in the protoplasts within 3 h, was maximal during a period of 18–36 h after electroporation, and then declined gradually. Alpha-amanitin added to the medium abolished the transient expression of the CAT gene. The closed circular form of input DNA was as effective as the linear form for the transient expression. The suspension culture was treated with aphidicolin, and S, G2, M and G1 phases were identified in the highly synchronized cell cycle obtained by releasing the cells from the inhibition of DNA synthesis. When a chimacric CAT gene was introduced into M phase protoplasts prepared from the synchronized culture, the transient expression of the CAT gene was 3–4 times higher than when it was introduced into protoplasts of other cell cycle phases. The frequency of stable transformation with a chimaeric neomycin phosphotransferase II gene was studied using the same system. G-418-resistant transformants were obtained from M phase protoplasts at frequencies 2–8 times those obtained from protoplasts at other cell cycle phases. The results indicate that the absence of the nuclear membrane in mitotic cells favours delivery to the nucleus of exogenous DNA introduced into the cytoplasm. 相似文献
49.
Gangliosides of thymuses from rabbit, mouse, rat, calf, and man were analyzed. The ganglioside compositions of the thymuses showed species specificities, and the compositions of the species other than the rabbit were found to be markedly different from that of the rabbit, which contained characteristically substantial amounts of IV3NeuGc-nLc4Cer and VI3NeuGc-nLc6Cer (Iwamori, M. & Nagai, Y. (1981) Biochim. Biophys. Acta 665, 214-220). The inter-species differences in the thymus ganglioside compositions were not remarkable in the 8 mouse and 2 rabbit strains examined. Rabbit thymocytes, but not those of mouse and rat, were lysed with human Hanganutziu-Deicher serum in the presence of guinea pig complement, reflecting the high content of gangliosides containing N-glycolylneuraminic acid in rabbit thymus. As to age-dependent changes of gangliosides in rabbit thymus and spleen, the concentrations gradually decreased with age, while the molar ratio of total gangliosides to total phospholipids was constant in the spleen throughout life and in the thymus at 3, 4, and 6 weeks of age. It was noted that old (180 weeks of age) rabbit thymus, which is occupied largely by fat tissue, still contained a significant amount of neolactoseries gangliosides. 相似文献
50.
Shingo Marumo Kazuya Sasaki Saburo Suzuki 《Bioscience, biotechnology, and biochemistry》2013,77(12):1931-1935
The relative stereochemistry of cervicarcin, an antitumor antibiotic, was determined as shown in 1, which represents the absolute stereochemistry also. 相似文献