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101.
The radiation sensitizers misonidazole (MISO) and desmethylmisonidazole (DMM) can produce central and peripheral neuropathy in patients and laboratory animals. Behavioral and pathological investigations have indicated that in the central nervous system this primarily involves the cochlear and vestibular systems. Nitroimidazoles can also interfere with glycolysis in vitro under aerobic and anaerobic conditions. In the present work we have studied the effect of MISO or DMM on lactate production and glucose utilization in mouse brain. It is observed that these compounds result in a 25% inhibition of lactate production in brain slices relative to the control at a 10 mM level. Additionally, MISO (1.0 mg/g/day) or DMM (1.4 mg/g/day) were administered daily (oral) for 1, 4, 7, or 14 days to examine the effect of these two drugs on the regional glucose utilization in C3Hf mouse brain. Five microcuries of 2-deoxy[14C]glucose was given following the last drug dose and autoradiographs of serial brain sections were made and analyzed by a densitometer. Following a single dose of either MISO or DMM, no significant differences in glucose uptake were observed when compared with controls. However, following 4, 7, and 14 doses the rate of glucose utilization was significantly reduced in the intoxicated animals. Larger reductions were measured in specific regions including the posterior colliculus, cochlear nuclei, vestibular nuclei, and pons with increasing effects observed at later stages. These results share a degree of correspondence with the regional brain pathology produced by these nitroimidazoles. 相似文献
102.
Summary The pituitary gland is first evident in rainbow trout two weeks before hatching. Differentiation of prolactin and ACTH cells is not marked until 3–4 days after hatching when the follicular arrangement of the prolactin cells become apparent. There is no difference in the time of development of either prolactin or ACTH cells in larvae reared in different ambient salinities despite marked changes in tissue ion and water content. This suggests that prolactin and ACTH do not play the osmo- and iono-regulatory roles in larval rainbow trout that they are considered to play in adult salmonids.The work was supported by a grant-in-aid of research from the National Research Council of Canada 相似文献
103.
104.
N Watanabe S Kojima F W Shen Z Ovary 《Journal of immunology (Baltimore, Md. : 1950)》1977,118(2):485-488
Under appropriate conditions of immunization combined with irradiation, SJL/J mice show a high and persistent anti-DNP IgE antibody response. Spleen cells transferred from normal untreated SJL mice suppress this response. Elimination of Ly-1+ cells, but not of Ly-2+ cells, abolished the capacity of spleen cells to suppress the IgE response. Thus of the three T cell Ly subclasses presently identified, Ly-1, Ly-2,3, and Ly-1,2,3, the normal SJL spleen cell which suppresses the IgE response of irradiated-immunized SJL mice belongs to the Ly-1 set. It is not known whether this Ly-1 cell suppresses the IgE response directly or by helping another cell in the recipient. The carrier-specific helper cell activity for IgE and probably IgG1 antibody response belongs to Ly-1 subclass in the SJL strain also. 相似文献
105.
J Shen F Wilson M Shifrine M E Gershwin 《Journal of immunology (Baltimore, Md. : 1950)》1977,119(4):1299-1305
Selective growth and clonal proliferation of human T lymphocytes can be achieved by using a single-phase semi-solid methylcellulose system without the requirement of preincubation with lectins. Significant proliferation, however, depends upon the continued presence of Con A or PHA, but not pokeweed mitogen or lipopolysaccharide within the methylcellulose. This procedure eliminates nonspecific agglutination by lectins and allows for direct visualization of colonies and their specific removal and subsequent cloning in liquid phase. Optimal growth and production of colonies greater than 40-cell size require 3 to 9 days. Individual cells can be identified on the basis of E rosette formation and absence of surface immunoglobulin or ability to phagocytize latex particles. Moreover, proliferation is inhibited by antithymocyte but not anti-B cell sera and can be demonstrated with peripheral blood T and MOLT-4 cells, but not with B or Raji cells. Finally, colony formation is not enhanced by the presence of 2-mercaptoethanol. The clonal proliferation of human T lymphocytes has wide application in the study of both antigen recognition and lymphocyte alterations in specific diseases. 相似文献
106.
107.
Shen K. Yang Harry V. Gelboin John D. Weber V. Sankaran Daniel L. Fischer James F. Engel 《Analytical biochemistry》1977
The optical isomers of (±)r-7,t-8-dihydroxy-7,8-dihydrobenzo[a]pyrene and its synthetic precursor (±)r-7,t-8-dihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene were resolved as their di-(−)menthoxyacetates using high-pressure liquid chromatography. Saponification of the resolved diesters yielded the corresponding enantiomers. The specific rotation, CD spectra, and ORD curves are reported. The resolution of these optical isomers permits detailed studies on the enzymatic intermediates and the mechanism of benzo[a]pyrene activation to its carcinogenic form. The method is of general usefulness for the resolution of optical isomers. 相似文献
108.
The calcium activation of the ATPase (ATP phosphohydrolase, EC 3.6.1.3) activity of cardiac actomyosin reconstituted from bovine cardiac myosin and a complex of actin-tropomyosin-troponin extracted from bovine cardiac muscle at 37 degrees C was studied and compared with similar proteins from rabbit fast skeletal muscle. The proteins of the actin complex were identified by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. Half-maximal activation of the cardiac actomyosin was seen at a calcium concentration of 1.2 +/- 0.002 (S.E. of mean) muM. A hybridized reconstituted actomyosin made with cardiac myosin and the actin-tropomyosin-troponin complex extracted from rabbit skeletal muscle was also activated by calcium but the half-maximal value was shifted to 0.65 +/- 0.02 (S.E. of mean) muM Ca2+. Homologous rabbit skeletal actomyosin showed half-maximal activation at 0.90 +/- 0.01 (S.E. of mean) muM Ca2+ and the value for a hybridized actomyosin made with rabbit skeletal myosin and the actin-complex from cardiac muscle was found at 1.4 +/- 0.03 (S.E. of mean) muM Ca2+ concentration. Kinetic analysis of the Ca2+ activated ATPase activity of reconstituted bovine cardiac actomyosin indicated some degree of cooperativity with respect to calcium. Double reciprocal plots of reconstituted actomyosins made with bovine cardiac actin complex were curvilinear and significantly different than those of reconstituted actomyosins made with the rabbit fast skeletal actin complex. The Ca2+-dependent cooperativity was of a mixed type as determined from Hill plots for homologous reconstituted bovine cardiac and rabbit fast skeletal actomyosin. The results show that cooperative interactions in reconstituted actomyosins were greater when the actin-tropomyosin-troponin complex was derived from cardiac than skeletal muscle. 相似文献
109.
Y Thomas L Rogozinski O H Irigoyen H H Shen M A Talle G Goldstein L Chess 《Journal of immunology (Baltimore, Md. : 1950)》1982,128(3):1386-1390
In the present report, we characterize a monoclonal antibody directed at a surface differentiation antigen on human T cells. The monoclonal antibody, OKT17, recognizes a cell surface antigen present on the majority of resting normal peripheral T cells. In contrast, OKT17 is unreactive with normal B cells, B cell lines, T cell lines, or SIg+ CLL. Interestingly, after activation, the antigen recognized by OKT17 is lost from a subset of OKT4+ cells. We took advantage of this finding to explore further the functional heterogeneity within activated OKT4+ cells. Evidence was obtained that the PWM-activated OKT4+ subset remaining after depletion of OKT17-reactive T cells (OKT4+ 17-) contains radiosensitive helperr cells but is devoid of suppressor cells. In contrast, the activated OKT4+ 17+ population contains potent radiosensitive suppressor cells as well as radioresistant helpe cells. Taken together, these studies suggest that the OKT17 monoclonal antibody can differentiate two functionally mature, activated OKT4+ human T cells: OKT4+ OKT17+ radiosensitive suppressor cells and OKT4+ 17- radiosensitive helper cells. 相似文献
110.
J T Billheimer M Y Shen H N Carnevale H R Horton E E Jones 《Archives of biochemistry and biophysics》1979,195(2):401-413
The enzyme that catalyzes the reversible conversion of N-acetylglutamic γ-semialdehyde and l-glutamate to α-N-acetyl-l-ornithine and α-ketoglutarate, acetylornithine δ-transaminase, has been isolated in homogeneous form and crystallized from both the wild-type and the arginine-inducible strains of Escherichia coli W. The molecular weight of the wild-type transaminase is 119,000 while the molecular weight of the arginine-inducible enzyme is 61,000. However, the arginine-inducible acetylornithine δ-transaminase is not a breakdown product of the wild-type, arginine-repressible transaminase. Analysis of crude extracts of the wild-type and arginine-inducible strains by varying the acrylamide concentration in polyacrylamide disc gel electrophoresis showed that arginine-inducible and wild-type transaminases differed in ionic charge. Immunochemical analysis of the two transaminases showed that neither enzyme would cross-react with antibodies prepared against its counterpart. Treatment of the two enzymes with sodium dodecyl sulfate, followed by disc gel electrophoresis revealed that both transaminases were composed of 31,000-dalton subunits. Tryptic digestion of the two transaminases showed that nearly identical peptides were present. The overall data suggest that the wild-type and inducible transaminases were products of two different structural genes. The two transaminases have different molecular weights, ionic charges, and antigenic determinants, but both are composed of similar molecular weight subunits and show a high degree of similarity in amino acid content and peptide composition. 相似文献