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91.
J. A. M. van Eekelen N. Y. Rots W. Sutanto M. S. Oitzl E. R. de Kloet 《The Journal of steroid biochemistry and molecular biology》1991,40(4-6):679-683
The present study examined the stress responsiveness of the hypothalamic-pituitary-adrenal axis in relation to the properties of corticosteroid receptors in the brain and pituitary in old (30 months) and young (3 months) male Brown Norway rats. The data demonstrate that circulating ACTH rather than the corticosteroid plasma level was elevated under basal conditions and following stress. Furthermore, a reduction of mineralocorticoid receptor (MR) number in the hippocampus and of glucocorticoid receptor (GR) number in the hypothalamus and the pituitary correspond to increased neuroendocrine responsiveness and negative feedback following stress. The changes in receptor binding do not parallel the changes in the amount of MR and GR mRNA measured with in situ hybridization. This suggests that the processing rather than the receptor gene expression is affected in senescence. 相似文献
92.
J Müller A Torsson M Damkjaer Nielsen K E Petersen J Christoffersen N E Skakkebaek 《Hormone research》1991,36(5-6):203-208
We have investigated gonadal development and growth in 4 individuals (3 with 46,XY and 1 with 46,XX karyotype) with P450scc deficiency. One patient died at 2 months of age from adrenal insufficiency, while the remaining 3 individuals were healthy and developed normally (age at follow-up: 18, 10 and 8 years). In the surviving individuals, the diagnosis was established during the first 2-4 months of life by extensive endocrine studies of blood and urine. In the remaining patient, the diagnosis was made on the basis of karyotype (46,XY), anatomy of internal and external genitalia and adrenal pathology. Gonadectomy was performed in the 2 surviving 46,XY individuals at the age of 7 years, and histological examination showed normal testicular morphology but very few germ cells. Postmortem examination of the testes of the 2-month-old subject showed normal testicular histology, and quantitative analysis revealed a normal number of germ cells. Ultrasound of the 46,XX individual showed normal internal female genitalia including ovaries with follicles. The 3 surviving patients grew along the 75th (46,XY), the 90th (46,XY) and the 50th percentile (46,XX), respectively. The oldest girl experienced normal breast and pubic hair development after oral estrogen replacement and topical testosterone administration. The glucocorticoid and mineralocorticoid replacement was adjusted in accordance with repeated measurements of serum sodium and serum potassium, plasma renin concentration and blood pressure. No attempts were made to normalize serum ACTH. We conclude that prenatal testicular maturation and development of female internal genitalia may take place in the absence of normal steroid hormone production. Normal growth and development may be obtained in P450scc-deficient individuals with adequate hormone replacement. 相似文献
93.
Summary In the solid substrate fermentation of cooked yellow corn grits with Rhizopus oligosporus in a rocking drum fermenter, temperature was controlled by blowing air through the substrate, forcing water evaporation. The rate of evaporation was controlled by the relative humidity of the air, according to the rate of heat generation during fermentation. Moisture content was maintained constant by spraying cold water on the substrate regulated by the water balance equation of the system. Both controls were operated by computer programs. The rocking motion in the reactor allowed even distribution of air and water in the substrate without disturbing the growing mycelia. 相似文献
94.
95.
Two trials of the isolation and enumeration of a given strain of Pseudomonas aeruginosa from water are reported. In each trial participants received concentrated samples from two batches, one with low and one with high counts, to be diluted to 500 ml in sterile distilled or deionized water and examined for Ps. aeruginosa by membrane filtration. Membranes were incubated at 37°C for 48 h on pads soaked in modified King's A broth (MKAB) and Unipath Pseudomonas Agar plus CFC supplement (PCFC). The first trial involved eight Public Health Laboratories (PHL) and the organizers provided media from single batches. The second trial, involving 50 PHL, examined the feasibility of a large scale external quality assessment (EQA) distribution. Participants were invited to use the same two media and their usual medium if different. Average counts were close to expected and the spread of results was comparable to that observed from the EQA scheme for indicator organisms. From the results of the two trials a better isolation of the strain of Ps. aeruginosa under consideration was noted with PCFC compared with MKAB. 相似文献
96.
Intra- and interbreed genetic variations of mitochondrial DNA major non-coding regions in Japanese native dog breeds [Canis familiaris) 总被引:1,自引:0,他引:1
Mitochondrial DNA (mtDNA) major non-coding regions were amplified from 73 dogs of eight Japanese native dog breeds and from 21 dogs of 16 non-Japanese dog breeds by the polymerase chain reaction and their DNA sequences were determined. A total of 51 nucleotide positions within the non-coding region (969–972 base pairs) showed nucleotide variations of which 48 were caused by transition. These nucleotide substitutions were abundant in the region proximate to tRNAPro. In addition to the nucleotide substitutions, the dog mtDNA D-loop sequences had a heteroplasmic repetitive sequence (TACACGTÀCG) involving size variation. The DNA sequences of the non-coding region were classified into four different groups by phylogenetic analysis and the deepest branchpoints of this dog phylogeny was calculated to about 100 000 years before the present. Phylogenetic analysis showed that Japanese native dog breeds could not be clearly delimited as distinct breeds. Many haplotypes found in members of some clustering groups were seen in each dog breed, and interbreed nucleotide differences between Japanese dog breeds were almost the same as the intrabreed nucleotide diversities. 相似文献
97.
98.
H Okada K Ishii K Nunoki T Abe N Taira 《Biochemical and biophysical research communications》1992,189(1):430-436
We have cloned a transient type K channel from rat heart (RH10) and coexpressed a metabotropic glutamate receptor (mGluR5) to study the functional modulation of RH10 coupled to the phosphatidylinositol (PI) hydrolysis. Stimulation of mGluR5 suppressed peak amplitude of RH10 current and affected voltage dependence of activation and inactivation of the channel. 相似文献
99.
P Kaliman V Baron N Gautier E Van Obberghen 《The Journal of biological chemistry》1992,267(15):10645-10651
To approach the question of why insulin-like growth factor-I (IGF-I) and insulin have different physiological actions, we developed antibodies directed against cytoplasmic regions of the IGF-I receptor exhibiting a low degree of homology with the corresponding sequences of the insulin receptor. We found that an antipeptide antibody directed against the beta-subunit carboxyl-terminal sequence (1232-1246) of the IGF-I receptor significantly reduced the in vitro receptor autophosphorylation. The ability of the synthetic peptide corresponding to the IGF-I receptor sequence 1232-1246 to abolish this inhibitory effect reflects the specific nature of the antibody interaction with the targeted domain in the receptor. Antipeptide antibody to IGF-I receptor sequence 1232-1246 also decreased receptor phosphorylation activity toward the exogenous substrate poly(Glu/Tyr). The reduction in poly(Glu/Tyr) phosphorylation was seen even when the antibody was incubated with a receptor previously activated and phosphorylated. Therefore, the inhibitory action on substrate phosphorylation is likely to be unrelated to the antibody reduction of receptor autophosphorylation but rather results from a global decrease in receptor enzymatic activity. The effect of the antipeptide antibody on receptor tyrosine kinase cannot be accounted for by a lowering of the receptor Km for ATP or of its affinity for the substrate poly(Glu/Tyr). Moreover, the interaction of the antibody with the receptor had no repercussion on the ligand binding site as shown by the unaltered IGF-I binding. Taken together our data suggest that the beta-subunit carboxyl-terminal domain of the IGF-I receptor plays a key role in regulating its kinase activity and that the particular sequence recognized by our antipeptide antibody could be involved in negative regulation of receptor functioning. 相似文献
100.
Ralf J. Jäger Vincent R. Harley Rudolf A. Pfeiffer Peter N. Goodfellow Gerd Scherer 《Human genetics》1992,90(4):350-355
A familial mutation in SRY, the gene coding for the testis-determining factor TDF, was identified in an XY female with gonadal dysgenesis, her father, her two brothers and her uncle. The mutation consists of a T to C transition in the region of the SRY gene coding for a protein motif known as the high mobility group (HMG) box, a protein domain known to confer DNA-binding specificity on the SRY protein. This point mutation results in the substitution, at amino acid position 109, of a serine residue for phenylalanine, a conserved aromatic residue in almost all HMG box motifs known. This F109S mutation was not found in 176 male controls. When recombinant wildtype SRY and SRYF109S mutant protein were tested in vitro for binding to the target site AAC AAAG, no differences in DNA-binding activity were observed. These results imply that the F109S mutation either is a rare neutral sequence variant, or produces an SRY protein with slightly altered in vivo activity, the resulting sex phenotype depending on the genetic back-ground or environmental factors.This paper is dedicated by G. S. to Professor Ulrich Wolf on the occasion of his 60th birthday 相似文献