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21.
The synthesis of 11-oxatestosterone from 11-oxa-5 alpha-androstane-3,17-dione, which is available from hecogenin, is described. The product shows, in comparison with the natural hormone, diminished androgenic and anabolic activities. 相似文献
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Using the indirect immunofluorescence staining technique, the occurrence and localization of proacrosin, the zymogen form of acrosin, was studied during spermatogenesis in the bull, ram, boar and rabbit. Proacrosin staining was demonstrable for the first time in the early haploid spermatid and increased with the differentiation of the spermatid to spermatozoon. The spermatozoon is covered by a cap-like structure of uniform fluorescence corresponding to the acrosomal compartment of the male gamete. No fluorescence could be found in diploid spermatogenic cells, i.e., in spermatogonia and spermatocytes. An identical developmental pattern of proacrosin was observed with the indirect immunoperoxidase staining technique. However, with this staining technique a distinct distribution of proacrosin staining was observed in the acrosome of epididymal and ejaculated spermatozoa of the bull, ram, boar, rabbit and man. Proacrosin seems to be distributed in the acrosome in granules rather than in the homogeneous form, as was indicated by the results of indirect immunofluorescence staining. 相似文献
23.
The resistance of Naegleria gruberi cysts to chlorine in the presence of cyanuric acid was compared at pH 5 and 7. An amperometric membrane electrode was used to measure HOCl concentrations independently of the chlorinated cyanurate species, thus permitting an analysis of the role of free chlorine versus chlorinated cyanurates in cyst inactivation. In the presence of cyanuric acid, the products of the HOCl residual and the contact time required for 99% cyst inactivation were 8.5 mg . min/liter and 13.9 mg . min/liter at pH 5 and 7, respectively. The Watson's Law coefficients of dilution (n) were 1.3 and 1.6 at pH 5 and 7, respectively. The results strongly suggest that HOCl is the predominant cysticide with no measurable cysticidal effect of the chlorinated cyanurate species. 相似文献
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As a consequence of polyploidization, the carp is endowed with three genetic loci coding for LDH in most tissues (and additional ones in liver). However, each such duplicated gene may not be functionally essential for the organism and could be eliminated. In a population survey, an electrophoretic polymorphism was detected which may best be interpreted by the assumption of a null allele, which is apparently not subject to selective pressure. Thus this originally duplicated gene would have diverged in the course of evolution without the origin of differences in function, so that one or the other of the genes is dispensable. 相似文献
26.
L A Engel H Menkes L D Wood G Utz J Joubert P T Macklem 《Journal of applied physiology》1973,35(1):9-17
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Zusammenfassung Die elektrophoretische Analyse der Isoenzyme der Sorbitdehydrogenase (SDH) bei verschiedenen Säugerspecies unter Einschluß des Menschen läßt darauf schließen, daß bei Säugern nur 1 Genlocus für dieses Enzym existiert. Auch bei Knochenfischen läßt sich in der Regel nur 1 SDH-Gen nachweisen. Eine Ausnahme bilden einige Species der Fischordnung Isospondyli. Innerhalb dieser Ordnung findet sich eine Diploid-tetraploid-Beziehung. Arten mit diploiden Charakteristika wie der Hering (Clupea harengus) besitzen 1 SDH-locus, an dem 3 Allele zu beobachten waren. Bei einigen phylogenetisch tetraploiden lachsartigen Fischen läßt sich eine Duplikation des SDH-Gens nachweisen. Während bei der Bachforelle (Salmo trutta) die nach der Tetraploidisierung zunächst identischen loci sich divergent entwickelt haben und jetzt diploidisiert sind, zeigen Regenbogenforelle (Salmo irideus) und Blaufelchen (Coregonus lavaretus) tetrasome Phänotypen der SDH. Beim Blaufelchen findet sich ein Überschuß an Heterozygoten, der auf eine meiotische Vorzugspaarung der Chromosomen mit identischen Allelen schließen läßt. Diese Befunde geben Einblick in den Mechanismus der Diploidisierung, der in der Evolution der höheren Wirbeltiere eine wesentliche Rolle gespielt haben dürfte.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
Sorbitol dehydrogenase isozymes in clupeoid fish: a further example of gene duplication through polyploid evolution
Summary Electrophoretic analysis of the sorbitol dehydrogenase isozymes (SDH) in various mammalian species including man revealed the existence of only 1 gene locus for this enzyme. As a rule, the same is true for Teleostean fishes. Some species of the fish order Isospondyli, however, represent an exception. Within this order, a diploid-tetraploid relationship exists. Species exhibiting diploid characteristics as the herring (Clupea harengus), are endowed with a single SDH gene locus at which 3 different alleles were observed. In some Salmonoid fish having passed through tetraploid evolution, a duplication of the SDH gene can be demonstrated. While in Salmo trutta the duplicated genes evolved divergently and became diploidized, in Salmo irideus and Coregonus lavaretus tetrasomic phenotypes occur. In Coregonus, the predominance of heterozygotes is to be interpreted as the consequence of preferential pairing of meiotic chromosomes endowed with identical alleles. These findings give some insight in the diploidization mechanism which may have played an important role during evolution of higher vertebrates.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
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K. Lynette Pearce Dr. Bernard T. Engel John R. Burton 《Applied psychophysiology and biofeedback》1989,14(3):207-217
Fifteen hypertensive patients were recruited from a geriatric medicine clinic for a research project designed to evaluate a Behavioral Stepped-Care treatment program of high blood pressure (HBP). All patients met the selection criteria of the Isolated Systolic Hypertension (ISH) in the Elderly (SHEP) clinical trial. During baseline, subjects recorded BP at home 9 times/day (3 times each, shortly after awakening, during the middle of the day, and within an hour of retiring) for 1 month and mailed that data to us daily. In addition, they came to the clinic weekly and had their BP recorded by a nurse. During treatment 1, systolic (SBP) feedback, they were trained to lower SBP at home using their sphygmomanometers. They also continued to monitor BP and to obtain weekly professional BP readings. During treatment 2 (relaxation), they were trained to relax; they followed the self-administration and data-collection protocol as in treatment 1. Each treatment phase lasted 3 months. Average monthly self-determined BP fell significantly from 166.4/85.8 (SBP/DBP) mm Hg during baseline to 153.3/81.2 by the end of the relaxation phase; average monthly professionally measured BP fell significantly, from 164.7/87.1 to 156.9/81.5. These findings show that a nurse-supervised, patient-administered behavioral treatment program of ISH can yield sustained, significant falls in BP.Ms. Pearce and Dr. Burton were supported in part by the Johns Hopkins Academic Nursing Home Award, PO, AG04402, from the National Institute on Aging. This material was presented in part at the annual meeting of the Gerontological Society of America, November 1988, San Francisco. 相似文献