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441.
The cholesterol of gallstones comes from the vesicular rather than the micellar phase of bile. Progress in this field has been limited because conventional analytical methods disturb the distribution of cholesterol between the two phases. The resonance of the cholesterol C6 proton occurs at a chemical shift of 5.4 ppm, to be shown by 2D NMR to be specific for biliary cholesterol, and arises only from the micellar mode. Thus integration of the C6 proton resonance peak area provides a direct non-invasive determination of the cholesterol distribution in human bile. 相似文献
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443.
Gabriela Andrejeva Sharon Gowan Gigin Lin Anne-Christine LF Wong Te Fong Elham Shamsaei Harry G. Parkes 《Autophagy》2020,16(6):1044-1060
ABSTRACT
Macroautophagy/autophagy can enable cancer cells to withstand cellular stress and maintain bioenergetic homeostasis by sequestering cellular components into newly formed double-membrane vesicles destined for lysosomal degradation, potentially affecting the efficacy of anti-cancer treatments. Using 13C-labeled choline and 13C-magnetic resonance spectroscopy and western blotting, we show increased de novo choline phospholipid (ChoPL) production and activation of PCYT1A (phosphate cytidylyltransferase 1, choline, alpha), the rate-limiting enzyme of phosphatidylcholine (PtdCho) synthesis, during autophagy. We also discovered that the loss of PCYT1A activity results in compromised autophagosome formation and maintenance in autophagic cells. Direct tracing of ChoPLs with fluorescence and immunogold labeling imaging revealed the incorporation of newly synthesized ChoPLs into autophagosomal membranes, endoplasmic reticulum (ER) and mitochondria during anticancer drug-induced autophagy. Significant increase in the colocalization of fluorescence signals from the newly synthesized ChoPLs and mCherry-MAP1LC3/LC3 (microtubule-associated protein 1 light chain 3) was also found on autophagosomes accumulating in cells treated with autophagy-modulating compounds. Interestingly, cells undergoing active autophagy had an altered ChoPL profile, with longer and more unsaturated fatty acid/alcohol chains detected. Our data suggest that de novo synthesis may be required to increase autophagosomal ChoPL content and alter its composition, together with replacing phospholipids consumed from other organelles during autophagosome formation and turnover. This addiction to de novo ChoPL synthesis and the critical role of PCYT1A may lead to development of agents targeting autophagy-induced drug resistance. In addition, fluorescence imaging of choline phospholipids could provide a useful way to visualize autophagosomes in cells and tissues. 相似文献
444.
A systematic approach to the various common aesthetic problems of the lower lateral cartilages is presented. Since this approach and technique may be applied to a wide variety of problems, we have taken the liberty of calling this the universal tip. These concepts have emerged from study of the literature and have evolved over the past thousand rhinoplasties. A classification of lower lateral cartilage problems includes five basic variations: (1) the wide, amphorous, ill-defined tip, (2) insufficient projection of the tip, (3) overprojection of the tip, (4) dependent tip with lack of definition, and (5) asymmetrical tip. It is important to realize that any of these five categories may be found in various combinations with each other. The details and fundamental steps of this universal tip technique are presented along with illustrative case examples in each of the five basic variations. In approximately 4 percent of patients there is a postoperative asymmetry in the position of cartilaginous flaps in the region of the dome of the lower lateral cartilage. These abnormalities plus abnormal ridges or bossa can usually be corrected at the time of secondary surgery under local anesthesia. 相似文献
445.
A S Parkes 《Perspectives in biology and medicine》1974,17(3):399-410
The relationship between coital rates, a quantitative index of sexuality, and the quality and quantity of reproduction is discussed in terms of sex ratio, delayed fertilization, frequency of intercourse, intercourse distribution within the menstrual cycle, acceleration of ovulation, and the quality of intercourse. Frequency of intercourse affects chances of conception, but its effect on twinning and sex ratio are unclear. Current research on reproduction offers little evidence of the effect of intercourse quality on reproduction in fully fecund individuals; research into the possible effect on reduced fecundity would be desirable. 相似文献
446.
B. Harris S. Othman J. A. Davies G. J. Weppner C. J. Richards R. G. Newcombe J. H. Lazarus A. B. Parkes R. Hall D. I. Phillips 《BMJ (Clinical research ed.)》1992,305(6846):152-156
OBJECTIVE--To define the relation between mood and autoimmune thyroid dysfunction during the eight months after delivery. DESIGN--Double blind comparison of the psychiatric status of women positive and negative for thyroid antibodies. Clinical examination and blood sampling for free triiodothyronine and thyroxine, thyroid stimulating hormone, and thyroid antibody concentrations at four weekly intervals. Psychiatric assessment at six, eight, 12, 20, and 28 weeks post partum. SETTING--Outpatient department of district hospital. PATIENTS--145 antibody positive women and 229 antibody negative women delivering between August 1987 and December 1989. MAIN OUTCOME MEASURES--Thyroid status. Number of cases of mental ill health by the general health questionnaire, research diagnostic criteria, Hamilton 17 item depression scale, hospital anxiety and depression scale, and Edinburgh postnatal depression scale. RESULTS--Six weeks after delivery the general health questionnaire showed 62 (43%) antibody positive women and 65 (28%) antibody negative women had mental ill health (chi 2 = 8.18, p less than 0.005). Follow up of 110 antibody positive and 132 antibody negative women showed significantly greater depression by research diagnostic criteria in antibody positive women (47%) than antibody negative women (32%) regardless of thyroid dysfunction. Antibody positive women showed higher mean scores for depression on the Hamilton (6.01 v 3.89, p = 0.0002), Edinburgh (7.45 v 5.92, p = 0.031), and hospital depression scales (4.95 v 3.79, p = 0.003). CONCLUSION--Depressive symptoms are associated with positive thyroid antibody status in the postpartum period. 相似文献
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448.
Carbonic anhydrase activity is increased in Friend erythroleukemia (FL) cells during the enhancement of erythroid differentiation in the presence of dimethylsulfoxide (DMSO) or butyric acid. Untreated FL cells show an increase in enzyme activity associated with logarithmic growth. The increase in the specific activity of carbonic anhydrase in the differentiating treated cells, however, appears to be due to at least two additional general mechanisms: (1) an induction of carbonic anhydrase paralleling the stimulation of hemoglobin synthesis and (2) the stability and/or retention of active carbonic anhydrase as compared to most of the other cell proteins. The stimulation of carbonic anhydrase activity in the treated cells is inhibited by 5-bromo-2'-deoxyuridine (BrdU). This is the first demonstration of BrdU inhibition of a DMSO induced product not directly related to hemoglobin. 相似文献
449.
450.