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Alkaline and acid phosphatase activities were studied in the ovary and oviducts of pullets from the age of 2-32 weeks. Adult fowls were similarly studied. Alkaline phosphatase activity was present only in the glandular grooves and crypts of the immature oviducts. Alkaline phosphatase activity appeared at the pits of epithelial evaginations as glandular formation commenced. The young, non-secreting glands also showed the enzyme activity. But in the mature oviduct, alkaline phosphatase activity was confined to only the uterovaginal glands or sperm host glands and the epithelium of the vagina. In the ovary, alkaline phosphatase activity in the theca interna increased as the diameter of the follicles increased. Acid phosphatase activity was not present in the ovary, but in the oviduct, the enzyme activity was present in the uterine (shell gland) glands and in the uterovaginal epithelium and glands (sperm host glands). Alkaline phosphatase activity in the ovarian follicles and in the immature oviduct is thought to be related to histodifferentiation of these structures. 相似文献
23.
TA Waldmann A Iio M Ogawa OR McIntyre W Strober 《Canadian Metallurgical Quarterly》1976,117(4):1139-1144
IgE metabolic turnover studies with purified radioiodinated IgE were performed in normal individuals and in a patient with IgE myeloma. The validity of the turnover studies was established in several ways, including comparisons of radioiodinated IgE turnover with the turnover of endogenously labeled 14C-IgE and with the turnover of infused unlabeled IgE in a patient with hypogammaglobulinemia. The geometric mean serum IgE concentration in 73 normal adults was 96 ng/ml with a 68% confidence interval of 24 to 386 ng/ml. Metabolic turnover studies in 10 control individuals disclosed a geometric mean total circulating IgE of 4.1 mug/kg, a mean percentage of the total exchangeable IgE in the intravascular space of 41%, a mean half-time of survival of IgE of 2.7 days, a mean fractional catabolic rate of 94% of intravascular pool per day, and a geometric mean synthetic rate of 3.8 mug/kg/day. IgE has the lowest synthetic rate and highest fractional catabolic rate of the five major classes of immunoglobulin molecules. In contrast to these normal values, a patient with IgE myeloma had a serum IgE comcentration of 42 mg/ml, a total circulating IgE of 1.7 g/kg, and a synthetic rate of 270 mg/kg/day. Furthermore, although the synthetic rate was vastly increased, the survival time was prolonged and the fractional catabolic rate was decreased to 5.1 days and 16 to 22% of the intravascular pool per day, respectively. These data are compatible with the concept that IgE is catabolized in part by a mechanism common to all immunoglobulin classes and in part by a unique mechanism not available to other immunoglobulins. At very high IgE serum concentrations, such as those encountered in patients with IgE myeloma, the unique mechanism would be saturated and only the catabolic pathways available to all immunoglobulins would be available to IgE. 相似文献
24.
One of the principal disadvantages of the passive pill as a telemetric method for measuring various physiological parameters has been its resticted range. The reasons for the restricted range with existing detection methods are discussed. An improved method using a locking spectrometer based on third-order phase-sensitive detection is described and its performance is assessed. A significant increase in the usable range of a high sensitivity passive pill is obtained. 相似文献
25.
It is well-known that in the chick, dietary protein increases the levels of several hepatic enzymes that are involved in nitrogen metabolism and excretion. However, the biochemical mechanism of this response is essentially unknown. The experiments presented in this paper show that the chick is responding to alpha-amino nitrogen and not to any specific amino acid. Furthermore, it is shown that this system responds to endogenous sources of nitrogen as well as dietary protein and that the xanthine dehydrogenase response involves regulation of enzyme synthesis without changing the rate of degradation. 相似文献
26.
Continuous conduction in demyelinated mammalian nerve fibers 总被引:1,自引:0,他引:1
27.
The report contains the results of clinico-dynamic studies of mental disorders in patients with Schilder's leukoencephalitis and subacute sclerosing panencephalitis after van-Bogart. The authors come to the conclusion that only parallel comparisons of the psychopathological symptomatology with focal neurological signs and a simultaneous study of the EEG and other paraclinical indices may facilitate the differential diagnosis of encephalitis. 相似文献
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Aflatoxins in food: occurrence, biosynthesis, effects on organisms, detection, and methods of control 总被引:14,自引:0,他引:14
W O Ellis J P Smith B K Simpson J H Oldham 《Critical reviews in food science and nutrition》1991,30(4):403-439
Aflatoxins are secondary metabolites produced by species of Aspergilli, specifically Aspergillus flavus and Aspergillus parasiticus. These molds are ubiquitous in nature and grow on a variety of substrates, thereby producing aflatoxins. Aflatoxins are of great concern due to their biochemical and biological effects on living organisms. In this article, the occurrence of aflatoxins, their biosynthesis, factors influencing their production, their effects on living organisms, and methods of detection and control in food are reviewed. Future areas of research involving mathematical modeling of factors influencing aflatoxin production and alternative methods of control, such as modified atmosphere packaging, are also discussed. 相似文献
30.