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排序方式: 共有412条查询结果,搜索用时 15 毫秒
1.
目的 探索LDH实验检测细胞活力的可行性。方法 原代培养骨髓细胞和软骨细胞,用LDH实验测定上述两组细胞的活力,并与镜下活体观察到细胞的生长状况相比较。与目前比较成熟的测定细胞活力的MTS实验的测得的值相比较。结果 LDH实验对上述两组细胞的活力的测定结果与镜下活体观察到的结果相符合。与MTS实验的测得的结果经统计学处理无显著差异。结论 LDH实验可用于细胞活力的直接测定,而对活细胞的生存、繁殖无影响。 相似文献
2.
Péter Várnai Gábor L. Petheö Judit K. Makara András Spät 《Pflügers Archiv : European journal of physiology》1998,435(3):429-431
Elevation of extracellular potassium concentration by as little as some tenth of mM activates rat adrenal glomerulosa cells.
In the present study some factors responsible for this high K+ sensitivity were examined. Using whole-cell voltage-clamp technique we found that both T-type and L-type voltage-dependent
Ca2+ channels have very low threshold potential (–71 and –58 mV, resp.). By means of patch-clamp technique combined with single-cell
fluorimetry we also provided evidence that the activation of Igl, a K+-activated inward rectifying current is associated with Ca2+ influx. Both the low activation threshold of voltage-dependent Ca2+ channels and the function of Igl contribute to the exceptional K+ sensitivity of the glomerulosa cells.
Received: 30 September 1997 / Accepted: 4 November 1997 相似文献
3.
M Kárteszi E Stark G Rappay F A László G B Makara 《The American journal of physiology》1981,240(6):E689-E693
Electrical stimulation of the neural lobe of the pituitary resulted in an increase of corticosterone secretion in both normal and Brattleboro rats. Bioassaying the corticoliberin (CRF) activity of stalk-median eminence and neural lobe extracts obtained from normal and Brattleboro rats revealed that the endogenous vasopressin was not a prerequisite of ACTH-releasing potency. Arginine-8-vasopressin failed to potentiate the CRF activity of the different extracts. These data suggest that a nonvasopressin substance(s) with CRF activity can be released from the neurohypophysis of the rat, and it may contribute to activating the pituitary-adrenal axis under certain experimental conditions. 相似文献
4.
Mutations in the Ca(2+)-sensing receptor gene cause autosomal dominant and sporadic hypoparathyroidism 总被引:3,自引:0,他引:3
Baron J; Winer KK; Yanovski JA; Cunningham AW; Laue L; Zimmerman D; Cutler GB Jr 《Human molecular genetics》1996,5(5):601-606
Parathyroid hormone secretion is negatively regulated by a 7- transmembrane
domain, G-protein coupled Ca(2+)-sensing receptor. We hypothesized that
activating mutations in this receptor might cause autosomal dominant
hypoparathyroidism (ADHP). Consistent with this hypothesis, we identified,
in two families with ADHP, heterozygous missense mutations in the
Ca(2+)-sensing receptor gene that cosegregated with the disorder. None of
50 normal controls had either mutation. We also identified a de novo,
missense Ca(2+)-sensing receptor mutation in a child with severe sporadic
hypoparathyroidism. The amino acid substitution in one ADHP family affected
the N-terminal, extracellular domain of the receptor. The other mutations
involved the transmembrane region. Unlike patients with acquired
hypoparathyroidism, patients with these mutations had hypercalciuria even
at low serum calcium concentrations. Their greater hypercalciuria
presumably reflected activation of Ca(2+)-sensing receptors in kidney
cells, where the receptor negatively regulates calcium reabsorption. This
augmented hypercalciuria increases the risk of renal complications and thus
has implications for the choice of therapy.
相似文献
5.
6.
T. A. Sapozhnikova F. S. Zarudii N. Zh. Baschenko S. F. Gabdrahmanova N. S. Makara R. Yu. Khisamutdinova N. A. Ivanova V. S. Nazarov 《Bulletin of experimental biology and medicine》2008,145(2):223-224
Therapeutic administration of 11-deoxymisoprostol had a hepatoprotective effect, which manifested in a decrease in the content
of alanine transaminase and aspartate transaminase in blood plasma, and produced a choleretic effect in rats with CCl4-induced toxic hepatitis.
__________
Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 2, pp. 183–184, February, 2008 相似文献
7.
8.
Dibenzo[a,l]pyrene-induced DNA adduction, tumorigenicity, and Ki-ras oncogene mutations in strain A/J mouse lung 总被引:1,自引:0,他引:1
Prahalad AK; Ross JA; Nelson GB; Roop BC; King LC; Nesnow S; Mass MJ 《Carcinogenesis》1997,18(10):1955-1963
Dibenzo[a,l]pyrene (DB[a,l]P), an environmental polycyclic aromatic
hydrocarbon, is the most potent carcinogen ever tested in mouse skin and
rat mammary gland. In this study, DB[a,l]P was examined for DNA adduction,
tumorigenicity, and induction of Ki-ras oncogene mutations in tumor DNA in
strain A/J mouse lung. Groups of mice received a single i.p. injection of
0.3, 1.5, 3.0, or 6.0 mg/kg DB[a,l]P in tricaprylin. Following treatment,
DNA adducts were measured at times between 1 and 28 days, while tumors were
counted at 250 days and analyzed for the occurrence of point mutations in
codons 12 and 61 of the Ki-ras oncogene. DB[a,l]P in strain A/J mouse lung
induced six major and four minor DNA adducts. Maximal levels of adduction
occurred between 5 and 10 days after injection followed by a gradual
decrease. DB[a,l]P-DNA adducts in lung tissue were derived from both anti-
and syn-11,12- dihydroxy-13,14-epoxy-
11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DB[a,l]PDE) and both
deoxyadenosine (dAdo) and deoxyguanosine (dGuo) residues in DNA as revealed
by cochromatography. The major adduct was identified as a product of the
reaction of an anti-DB[a,l]PDE with dAdo in DNA. DB[a,l]P induced
significant numbers of lung adenomas in a dose- dependent manner, with the
highest dose (6.0 mg/kg) yielding 16.1 adenomas/mouse. In
tricaprylin-treated control animals, there were 0.67 adenomas/mouse. Based
on the administered dose, DB[a,l]P was more active than other environmental
carcinogens including benzo[a]pyrene. As a function of time-integrated DNA
adduct levels, DB[a,l]P induced lung adenomas with about the same potency
as other PAHs, suggesting that the adducts formed by DB[a,l]P are similar
in carcinogenic potency to other PAHs in the strain A/J mouse lung model.
Analysis of the Ki- ras mutation spectrum in DB[a,l]P-induced lung tumors
revealed the predominant mutations to be G-->T transversions in the
first base of codon 12, A-->G transitions in the second base of codon
12, and A-->T transversions in the second or third base of codon 61,
concordant with the DNA adduct profile.
相似文献
9.
The site of inhibitory action of glucocorticoids on the hypothalamic corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) was studied using a combination of glucocorticoid implantation and immunohistochemistry. Adrenalectomy increased the number and the staining intensity of the neurons containing CRF-like immunoreactivity in the anterior and medial parvicellular subdivisions of the paraventricular nucleus (PVN) and induced the appearance of AVP-like immunoreactivity in the same cell population. These effects of adrenalectomy were inhibited only by those dexamethasone implants which were placed close to the PVN. Unilateral implantation of dexamethasone into the PVN inhibited the adrenalectomy-induced changes in CRF and AVP immunostaining only on the implanted side. Dexamethasone implants placed into the hippocampus decreased the effect of adrenalectomy in the PVN while similar implants into the amygdala and cerebral cortex were ineffective. These results suggest that the primary site of glucocorticoid feedback inhibition on the hypothalamic secretagogues of adrenocorticotropin is the PVN. 相似文献
10.
gamma-Aminobutyric acid stimulates pituitary growth hormone secretion in the neonatal rat. A superfusion study 总被引:1,自引:0,他引:1
The putative inhibitory neurotransmitter gamma-aminobutyric acid (GABA) elicited a dose-dependent increase in GH secretion from the pituitary of newborn rats. GH secretion increased within 3 min after GABA administration with a peak response at 5-6 min. The lowest effective dose of the GABA agonist muscimol was about 10 times smaller than that of GABA. The GABA effect was antagonized by picrotoxin and bicuculline, suggesting that GABA acts at GABA-A type receptors. The pituitary responsiveness to GABA gradually decreased during the second and third postnatal weeks. If the neonatal pituitaries were continuously exposed to GABA for 3 h GH secretion rapidly increased to a maximum within the first 10 min and then gradually decreased to a less elevated level by 1 h and remained at this level for the next 2 h. After 3 h of GABA exposure muscimol had no effect on GH secretion but human pancreatic GH-releasing factor stimulated it, indicating receptor desensitization during prolonged GABA administration. The significance of GABAergic regulation of GH secretion in the neonate is emphasized by the finding that simultaneous administration of picrotoxin diminished the GH releasing activity of the hypothalamic extract of 2-day-old rats by more than 60%. These results indicate that in the postnatal period the regulation of GH secretion differs from that of the adult animal and GABA might play an important role in the maintenance of the high GH secretion during the first days of life. 相似文献