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81.
Cell Proliferation Inhibition in Reduced Gravity 总被引:1,自引:0,他引:1
Extended durations of spaceflight have been shown to be deleterious on an organismic level; however, mechanisms underlying cellular sensitivity to the gravitational environment remain to be elucidated. The majority of the gravitational studies to date indicates that cell regulatory pathways may be influenced by their gravitational environment. Still, few cell biology experiments have been performed in space flight and even fewer experiments have been repeated on subsequent flights. With flight opportunities on STS-50, 542 and 57, Sf9 cells were flown in the BioServe Fluids Processing Apparatus and cell proliferation was measured with and without exposure to a cell regulatory sialogycopeptide (CeReS) inhibitor. Results from these flights indicate that the Sf9 cells grew comparable to ground controls, that the CeReS inhibitor bound to its specific receptor, and that its signal transduction cascade was not gravity sensitive. 相似文献
82.
Jill M. Delfs Lei Yu †Gaylord D. Ellison Terry Reisine Marie-Françoise Chesselet 《Journal of neurochemistry》1994,63(2):777-780
Abstract: The mRNA encoding μ-opioid receptors is expressed in neurons of the globus pallidus, a region of the basal ganglia that receives a dense enkephalinergic innervation from the striatum. The regulation of the mRNAs encoding the opioid peptide enkephalin in the striatum and the μ-opioid receptor in the globus pallidus was examined with in situ hybridization histochemistry following short- or long-term haloperidol treatments, which alter striatal enkephalin mRNA levels. Animals were administered haloperidol daily for 3 or 7 days (1 mg/kg, s.c.) or continuously for 8 months (1 mg/kg, depot followed by oral). Enkephalin and μ-opioid receptor mRNA levels were unchanged after 3 days of haloperidol treatment. In contrast, the enkephalin mRNA level was increased in the striatum, and μ-opioid receptor mRNA levels were markedly decreased in the globus pallidus after 7 days of haloperidol administration. Similar effects were observed in rats treated with haloperidol for 8 months. The results provide the first evidence of regulation of μ-opioid receptor mRNA in vivo. 相似文献
83.
This paper documents the diversity and variation in the circumorbital foramina in extant primates. A qualitative and quantitative
analysis of the circumorbital foramina, comprising the supraorbital foramen, the infraorbital foramen, and the malar foramen,
was carried out using representative species from nine extant families of primates. The information obtained from the study
is used to reconstruct ancestral morphotypes, and to make inferences about evolutionary changes that may have taken place
in the major primate lineages. In addition, the analysis provides useful comparative data for interpretation of the phylogenetic
significance and paleobiological implications of the circumorbital foramina in fossil primates. 相似文献
84.
Rho and RNA: models for recognition and response 总被引:12,自引:1,他引:11
Terry Platt 《Molecular microbiology》1994,11(6):983-990
85.
Sean Clark Michael A. McGuckin Terry Hurst Bruce G. Ward 《Cancer immunology, immunotherapy : CII》1994,39(2):100-104
This study aimed to investigate whether the biological response modifiers (BRM) interferon (IFN) and tumour necrosis factor (TNF) could enhance the cytotoxic action of cisplatin on ovarian tumour cells in vitro. The sensitivity of four cell lines (OAW42, GG, JAM and PE01) to drugs and drug combinations was tested by a radiolabelled-thymidine incorporation assay. Cell lines demonstrated a range of sensitivity to cisplatin and the innate cytotoxic effect of each of the BRM. When IFN was used in combination with cisplatin, a significant enhancement of cisplatin toxicity occurred in three of four cell lines. TNF demonstrated such an effect in two cell lines but diminished the toxicity of cisplatin in one cell line. A purely additive effect of the agents may explain the enhanced toxicity of cisplatin in some of these cases. However, in one cell line at least (PEO1), both TNF and IFN demonstrated a clearly synergistic effect with cisplatin. These BRM used in conjunction with cisplatin may provide better antitumour regimen than cisplatin alone in some patients with ovarian cancer, but the response is likely to be heterogeneous between patients. 相似文献
86.
We previously reported a significant derangement of intracellular free calcium ion concentration in the isolated perfused kidney of adult spontaneously hypertensive rat (SHR) (J. Biol. Chem. 267, 3637–3643, 1992). In order to investigate whether an abnormality in intracellular free calcium or another ion precedes the development of elevated blood pressure in SHR, we have now compared intracellular free Ca2+, Na+ and pH, using 31P, 19F, and triple quantum-filtered (TQ) 23Na NMR, in perfused kidneys from prehypertensive young SHR and normotensive young Wistar-Kyoto (WKY) rats (5–6 weeks old) which showed no significant difference in blood pressure B.P.=120±5 mmHg and 115±3 mmHg, for SHR and WKY rats, respectively). Like the adult kidney, no significant differences in intracellular ATP concentration or intracellular pH were found between young prehypertensive SHR and normotensive WKY rat kidneys. The TQ 23Na NMR signal was 47% higher in the SHR kidney, but, due to biological variability and measurement errors, this difference could not be shown to be statistically significant. However, a significant (40%; P<0.05) increase was found in O2 consumption rate, a measure of the Na+/K+-ATPase activity, of the young prehypertensive SHR kidney in comparison to the age-matched WKY rat kidney (7.25±0.75 for SHR vs. 5.17±0.18 μmola O2/min g for WKY rat, n = 6). Furthermore, a highly significant (92%; P<0.02) increase in intracellular free Ca2+ concentration was observed in kidneys from young SHR that had noy yet been developed high blood pressure in comparison to the kidneys from young normotensive WKY rats (648±76 nM vs. 339±39 nM, n = 4, despite the fact that there was no significant difference in blood pressure. Increased intracellular free Ca2+ thus appears to be part of a primary defect, in the prehypertesive young SHR kidney, which may, by way of increased release of arachidonic acid, and subsequent increased production of vasoconstricting arachidonic acid metabolites via the cytochrome P450 pathway, induce elevated blood pressure in the adult SHR. 相似文献
87.
Facilitation of Sexual Receptivity by Ventromedial Hypothalamic Implants of the Antiprogestin RU 486
RU 486 is known primarily as an antagonist to progestins and glucocorticoids. However, RU 486 has also been shown to have agonistic progestational properties in biochemical and behavioral studies. In the current study, RU 486 was implanted directly into tim ventromedial hypothalamus (VMH) to test for facilitative action on the receptive behavior of female ovariectomized Long-Evans rats primed with 5 μg of estradiol benzoate. Cannulae containing RU 486, progesterone (P), or empty cannulae were implanted 48 hr after estrogen priming. The lordosis quotient and the lordosis score were assessed 4 hr after the cannulae were lowered by a standardized test consisting of 10 mounts by a stimulus male. P and RU 486 significantly facilitated receptivity compared to blank implants in terms of lordosis quotient and lordosis score, with no significant difference between the hormone treatments. While only a single dose of each treatment was given in the current study, RU 486 facilitated lordosis when implanted to the VMH as well as progesterone in contrast to our previous results where the steroids were administered systemically. 相似文献
88.
Expression analysis of the mixed function oxidase system in rat brain by the polymerase chain reaction 总被引:3,自引:0,他引:3
Anne V. Hodgson Terry B. White James W. White Henry W. Strobel 《Molecular and cellular biochemistry》1993,120(2):171-179
Metabolism of therapeutic drugs in the body by the mixed function oxidase system is an important consideration in the analysis of a drug's effectiveness. P450-dependent metabolism within the brain of a neuro-specific drug may affect the drug's course of action. To determine whether cytochrome P450 was expressed in brain, RNA was isolated from the whole brains of rats treated with a variety of known hepatic P450 inducers, including amitriptyline, imipramine, isosafrole, phenobarbital, and -naphthoflavone. The RNA was analyzed for the presence of P450 isozymes by the PCR technique. Differential expression of P450IA1, P450IIB1, P450IIB2, P450IID, and P450IIE1 was detected in the brain samples, depending on the treatment. Cytochrome P450 reductase expression was also detected in the brain samples, giving strong evidence that the brain contains a competent mixed function oxidase system under all conditions studied. (Mol Cell Biochem120: 171–179, 1993)Thesis student of the Graduate School of Biomedical Sciences, the University of Texas Health Science Center at Houston 相似文献
89.
David I. Dunstan Terry D. Bethune Cheryl A. Bock 《In vitro cellular & developmental biology. Plant》1993,29(3):109-112
Summary The production of cotyledonary somatic embryos of white spruce from cultures grown long-term as suspensions was investigated.
We report the effects of removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from the maintenance medium (ordinarily containing
both 2,4-D and benzyl adenine) before (±)-ABA-stimulated maturation. In particular the use of a 1-wk culture period
without 2,4-D was found to improve the production of normal-looking cotyledonary somatic embryos. Using high performance liquid
chromatography analyses of culture supernatants, it was determined that this affect was not related to altered ABA metabolism.
Germination of cotyledonary somatic embryos from cultures pretreated by the 1-wk culture period without 2,4-D was improved
compared with similar embryos from cultures that had not been pretreated. 相似文献
90.
Alfonso Gonzalez Terry D. Oberley Janice L. Schultz Jennifer Ostrom Jonathan J. Li 《In vitro cellular & developmental biology. Animal》1993,29(7):562-573
Summary Primary diethylstilbestrol-induced kidney tumors from Syrian hamsters were grown in vitro and maintained in culture for 6
mo. Combined immunohistochemical studies using antibodies to intermediate filaments and ultrastructural studies of tumor cells
in culture exhibited characteristics similar to tumor cells in vivo. Furthermore, the cells manifested transformed properties
in culture; they grew both as multilayered colonies attached to the tissue culture substrate and as floating multicellular
colonies (spheroids). When cultured cells were injected into diethylstilbestrol-treated recipient hamsters, tumors developed
at the injection sites. In contrast, renal tubules or whole kidney cortex from control hamsters cultured in the same medium
underwent only short-term growth, with senescence developing after approximately 1 mo. However, cell cultures of kidney cortex
from animals treated in vivo for 5 mo. with diethylstilbestrol formed a cell line. This diethylstilbestrol-induced cell line
has been maintained in culture for 1.5 yr and has the following characteristics: a) it is anchorage-dependent, b) it is negative
in in vivo tumorigenicity tests, and c) cultured cells are histochemically and ultrastructurally similar to cultured tumor
cells. This culture system should prove to be of use in studying hormonal carcinogenesis in vitro.
This study was supported by the Medical Research Service, Department of Veterans Affairs, Washington, DC, and by grant CA-22008
from the National Cancer Institute, NIH, DHHS, Bethesda, MD. 相似文献