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151.
Stanley M. Garn Andrew K. Poznanski Jerrold M. Nagy Mary B. McCann 《American journal of physical anthropology》1972,36(2):295-298
Analysis of hand radiographs of juvenile siblings of juvenile propositi indicates that brachymesophalangia-5 alone (without cones) is separately inherited without apparent sex bias while brachymesophalangia-5 with the cone-epiphysis of mid-5 and the cone-epiphysis of mid-5 alone are both apparently inherited as a complex and with a marked excess of females over males. 相似文献
152.
Frances V. McCann Theodore M. Keller Paul M. Guyre 《The Journal of membrane biology》1987,96(1):57-64
Summary The human cell line U-937 has been used extensively to model many macrophage functions. We have examined the cell membranes of human monocyte-derived macrophages (HMDM) and U-937 cells to compare membrane properties as expressed by single ion channel currents. The patch-clamp technique was applied to isolated, nonactivated, inside-out patches of cell membranes obtained from HMDM and from the U-937 cell line. Voltage-gated potassium channels of similar conductance but different kinetics are present in both types of cells, and a calcium-activated potassium channel is present only in the HMDM. These differences in ion channel properties suggest fundamentally different behavior between these two cell types at the level of the cell membrane. 相似文献
153.
The Salmonella typhimurium/mammalian microsomal assay. A report of the U.S. Environmental Protection Agency Gene-Tox Program 总被引:3,自引:0,他引:3
L D Kier D J Brusick A E Auletta E S Von Halle M M Brown V F Simmon V Dunkel J McCann K Mortelmans L E Kier 《Mutation research》1986,168(2):69-240
The Salmonella assay has been in use for almost 15 years and can be defined as a routine test for mutagenicity and for predicting potential carcinogenicity. It detects the majority of animal carcinogens and consequently plays an important role in safety assessment. The test is also routinely used as the frontline screen for environmental samples (complex mixtures) isolated from air, water and food. This role will continue to remain an area of growth as or because sample volumes associated with these testing areas are generally very limited and more extensive testing is generally impossible. While this test, like all others, has some limitations, it is recommended that it be regularly included in all genetic testing batteries. 相似文献
154.
Inhibition of Ornithine Decarboxylase and Growth of the Fungus Helminthosporium maydis 总被引:2,自引:1,他引:1
α-dl-Difluoromethylornithine (DFMO), a specific enzyme-activated inhibitor of ornithine decarboxylase, at 0.5 to 2.0 millimolar significantly inhibited mycelial growth and especially sporulation of Helminthosporium maydis in the dark; its inhibitory effect on sporulation was greatly increased under light conditions. Putrescine at 0.25 millimolar fully prevented the inhibitory effects of DFMO; the inhibition caused by the latter could not be prevented by cadaverine or CaCl2. α-dl-Difluoromethylarginine, a specific enzyme-activated inhibitor of arginine decarboxylase, at 0.1 to 2.0 millimolar had a weak inhibitory effect on the fungus. The effect was not dependent on the inhibitor concentration and there was no detectable arginine decarboxylase activity in the fungus. 相似文献
155.
The luteinizing hormone (LH)-releasing activities a pooled rat organum vasculosum lamina terminalis (OVLT) and median eminence (ME) tissues were evaluated for chromatographic and biologic similarity and compared to those of synthetic decapeptide LH-releasing hormone (LHRH). The LHRH detected in these extracts appeared similar chromatographically (Sephadex G-25) to synthetic LHRH. These extracts, as well as synthetic LHRH, were also capable of stimulating dose dependent gonadotropin release form cultures rat gonadotrophs. These findings suggest a physiological role of the LHRH present in the rat OVLT in the control of gonadotropin secretion. 相似文献
156.
The effects of third ventricular (IVT) injection of 25 μg of bradykinin (BK) upon plasma levels of LH, FSH, TSH, GH and prolactin were investigated in conscious ovariectomized female rats bearing indwelling jugular cannulae. Some animals were pretreated with bradykinin potentiating factor (BPF). Intravenous administration of BK had no effect upon hormone levels. IVT injection of BK significantly depressed plasma prolactin levels at 15 and 30 min post-drug, with levels returning to control values by 60 min. Pretreatment of animals with BPF (75 μg/3 μl) prolonged the prolactin suppression induced by BK for up to two hours. Plasma LH, FSH, TSH and GH levels in BK-rats were not significantly different from those of saline-injected animals at any time point measured. Neither BPF alone nor in conjunction with BK had any effects upon plasma levels of TSH; however, BK plus BPF suppressed FSH concentrations at 75 min post-BPF, while BPF alone appeared to increase GH levels at 45 min. In vitro incubation of hemipituitaries with 0.083, 0.83 or 8.33 μg/ml BK had no effect upon the release of LH, TSH or prolactin compared to control values. However, the secretion of GH and FSH was suppressed by the lowest dose of BK tested. These results suggest that BK may play a physiological inhibitory role in the regulation of prolactin, which can be augmented by preventing its degradation, i.e. via BPF. The effect of the peptide seems to be mediated by the CNS since neither intravenous injection of BK nor in vitro incubation of pituitaries with the peptide modified prolactin release. 相似文献
157.
The effect of vasoactive intestinal peptide (VIP) on anterior pituitary hormone release was examined in a variety of in vitro preparations. Synthetic VIP was capable of stimulating increased prolactin (PRL) release from male rat hemipituitaries in doses as low as 10−9 M only when the enzyme inhibitor bacitracin was present in the incubation medium. Natural porcine VIP was similarly capable of stimulating PRL release, but only at higher doses (10−6 M). Additionally, synthetic VIP was capable of stimulating PRL release from dispersed anterior pituitary cells harvested from adult male and lactating female rats and from an enriched population of lactotrophs obtained by unit gravity sedimentation of similar dispersed cells from infantile female rats. No effect of VIP on luteinizing hormone, growth hormone or thyroid stimulating hormone release was seen. These findings taken in concert with the presence of VIP in the hypothalamus, pituitary and hypophyseal portal plasma of the rat suggest a physiological role for VIP in the control of PRL secretion. 相似文献
158.
Summary Plasmid R46 was successfully transferred from Escherichia coli K-12 into Myxococcus xanthus strain MD-1 but not into M. xanthus strain XK. Plasmid R68.45 was transferred from E. coli K-12 into both strains of M. xanthus. The effects of these plasmids on survival of M. xanthus after ultraviolet (UV)-254 nm irradiation, the ability of M. xanthus to reactivate irradiated myxophages, and Weigle reactivation of UV-irradiated myxophages by M. xanthus were studied. Plasmid R46 had no effect on UV survival of M. xanthus, but increased the host's ability to reactivate irradiated myxophages. Plasmid R68.45 protected M. xanthus strains MD-1 and XK against the lethal effects of UV irradiation and also increased the host's ability to reactivate irradiated myxophages. 相似文献
159.
Lancelot Barrington-Ward Hubert Bond Edwin Bramwell Duncan C. L. Fitzwilliams Francis Fraser R. S. Frew William Goschen F. J. McCann Macmillan Arthur MacNalty Frederick Kay Menzies George Newman George Riddoch Humphry Rolleston Bertram Shires Frederick Still G. A. Sutherland James Taylor James Walton David Wilkie 《BMJ (Clinical research ed.)》1938,2(4046):195-196
160.
The putative sigma factor KatF has a central role in development of starvation-mediated general resistance in Escherichia coli. 总被引:51,自引:30,他引:21
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KatF is required for the expression of some 32 carbon starvation proteins in Escherichia coli including 6 previously identified as Pex. Mutants with the katF gene survive carbon and nitrogen starvation poorly. Many of the KatF-regulated starvation proteins are common to those induced by other stresses, and the mutant failed to develop starvation-mediated cross protection to osmotic, oxidative, and heat stresses. Furthermore, thermal resistance was not induced in the mutant by heat preadaptation, and it exhibited an altered pattern of protein synthesis at elevated temperature. Thus, KatF is a major switch that controls the starvation-mediated resistant state in E. coli. 相似文献