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91.
92.
Fc-receptor heterogeneity of human suppressor T cells. 总被引:25,自引:0,他引:25
A R Hayward L Layward P M Lydyard L Moretta M Dagg A R Lawton 《Journal of immunology (Baltimore, Md. : 1950)》1978,121(1):1-5
Concanavalin A (Con A) stimulated the IgM-binding subpopulation of human T cells (TM) to suppress the pokeweed mitogen-induced differentiation of B lymphocytes to plasma cells. Control TM cells that had not been Con A activated did not suppress. The degree of suppression was related to the number of Con A-TM cells added to the cultures and it was abolished by irradiation of the T lymphocytes either before or after the 24-hr culture period with Con A. Suppression did not require the presence of TG cells, whose suppressor potential has been previously established. These findings indicate that suppressor activity is not confined to the TG subpopulation but may be expressed by TM cells also. 相似文献
93.
The rates of death from ischaemic heart disease in the United Kingdom in the years after 1968 were studied to establish whether any general trend had occurred. A decline in the rates began after 1973-4, was greatest in those aged 35-44 years, and occurred among both men and women and in each of the regions of England and in Wales and Scotland. Total dietary fat intake had started to fall about five years earlier, and this may provide part of the explanation. Changes in smoking habits also occurred but were more difficult to relate to the pattern of change in the death rates. If a general decline in ischaemic heart disease has begun in the United Kingdom a case may be made for close monitoring of changes in lifestyle and medical practice in different demographic groups to try to find the explanation. 相似文献
94.
95.
Alain B langer Mich le Brochu Daniel Lacoste Caroline Noë l Fernand Labrie Andr Dupont L onello Cusan Simon Caron Jean Couture 《The Journal of steroid biochemistry and molecular biology》1991,40(4-6):593-598
We studied the relationship between circulating androsterone glucuronide, androstane-3,17β-diol glucuronide and androstane-3β,17β-diol glucuronide concentrations and adrenal as well as testicular C-19 steroids in men. Among the three 5-reduced steroid glucuronides, androsterone glucuronide is the predominant C-19 steroid measured in plasma and its levels are markedly elevated compared to those of the non-conjugated steroid. The marked rise in testosterone during puberty was strongly correlated with the increase in both androsterone glucuronide and androstane-3,17β-diol glucuronide, thus suggesting that testicular C-19 steroids are the main precursors of the steroid glucuronides. We also found that the presence of testicular androgen in plasma contributes to approx. 70% of plasma androsterone glucuronide and androstane-3,17β-diol glucuronide. Our data suggest that the adrenal C-19 steroids remaining in circulation after castration in men are converted into potent androgen which are then glucuronidated by UDP-glucuronyltransferase. We also demonstrated that the human prostate cell line LNCaP is capable of converting to a large extent androstenedione into androsterone glucuronide. Our data further confirm that glucuronidation is a major pathway of steroid metabolism in steroid target tissues. 相似文献
96.
Johan B. Ubbink W. J. Hayward Vermaak Siegbert Bissbort 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1991,565(1-2)
A rapid, isocratic high-performance liquid chromatographic (HPLC) method is described for the determination of total homocysteine levels in human serum. Prior to reversed-phase HPLC analysis, the serum thiols were derivatized with SBD-F (ammonium 7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate), a thiol-specific fluorogenic probe which is commercially available. Retention of SBD-homocysteine was sensitive to pH, and a mobile phase pH of 2.1 ensured baseline separation of serum thiols within 6 min. The method is simple, sensitive, reproducible (between-run coefficient of variation of 6.6%) and very suitable for routine determination of serum homocysteine levels in a clinical pathology laboratory. 相似文献
97.
98.
Polymorphic analysis of the three MHC-linked HSP70 genes 总被引:10,自引:0,他引:10
Three genes encoding members of the M
r 70 000 heat shock protein family (HSP70) are known to lie in the class III region of the human major histocompatibility complex. IN order to determine whether these genes or their protein products exhibit any polymorphism the three genes have been specifically amplified from genomic DNA and sequenced. The HSP70-1 and HSP70-2 genes encode the major heat-inducible HSP70. A comparison of the nucleotide sequences of these genes from B8, SC01, DR3, B18, F1C30, DR3, and B7, SC30, DR2 haplotypes has revelad only very limited sequence variation which is not associated with any amino acid polymorphism. The HSP70-Hom gene encodes a protein that is highly related to HSP70-1, but which is not heat-inducible. Nucleotide sequence analysis of this gene from different haplotypes has revealed a Met Thr amino acid substitution at residue 493 in a number of the haplotypes tested. This variable amino acid lies in the proposed peptide-binding site of the HSP70-Hom protein.
Address correspondence and offprint requests to: R. D. Campbell. 相似文献
99.
Construction and characterisation of a yeast artificial chromosome library containing three haploid maize genome equivalents 总被引:6,自引:0,他引:6
Keith J. Edwards Helen Thompson David Edwards Antoine de Saizieu Caroline Sparks John A. Thompson Andrew J. Greenland Mark Eyers Wolfgang Schuch 《Plant molecular biology》1992,19(2):299-308
We have constructed a yeast artificial chromosome (YAC) library using high-molecular-weight DNA prepared from agarose-embedded leaf protoplasts of the maize inbred line UE95. This library contains 79 000 clones with an average insert size of 145 kb and should therefore represent approximately three haploid genome equivalents. The library is organised as an ordered array in duplicate microtitre plates. Forty-one pools of DNA from 1920 individual clones have been prepared for rapid screening of the library by the polymerase chain reaction (PCR). Using this approach, together with conventional colony hybridisation, we have been able to identify between one and eight positive clones for every probe used. 相似文献
100.
Nasi Mian Caroline E. Anderson Andrew J. Pope Anthony R. Smith Paul S. Richardson Kim Balfre Paul W. Kent 《The Biochemical journal》1982,208(2):425-433
Chicken tracheal mucosa in vitro transported and incorporated radioactive precursors into mucins, which were secreted at a steady rate into the tracheal lumen. Secretion of mucins labelled with 35S and 3H after pulse-labelling of the mucosal layer with Na235SO4 and d-[1-3H]glucosamine as precursors was an energy-dependent process, as it was strongly inhibited by the action of respiratory-chain inhibitors, an uncoupler of oxidative phosphorylation, a metabolic blocker and a temperature shift from 41°C to 5°C. On the other hand, both cholinergic and parasympathomimetic agents considerably increased the secretion of dual-radiolabelled mucins when applied on the submucosal side of the trachea. The effect of Ca2+ was directional, since only high submucosal (3.6 or 18mm) or low luminal (zero or 0.18mm) Ca2+ massively enhanced the secretion of radiolabelled mucin compared with the mucin output measured under physiological Ca2+ conditions (1.8mm). Whereas application of ionophore A23187 on either side of the trachea significantly increased mucin output, its presence in the appropriate tracheal compartment and under appropriate Ca2+ conditions further accentuated the output of radiolabelled mucins. Addition of acetylcholine under appropriate conditions also had an additive effect on the Ca2+-stimulated secretion of mucins. Ca2+ stimulation of mucin secretion appears to be dependent on the metabolic integrity of the mucosal cells. Mucins secreted in response to high submucosal and low luminal [Ca2+] appear to consist of a number of different types of glycoproteins, as judged from their ion-exchange-chromatographic behaviour. 相似文献