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81.
Herbert M. Evans Miriam E. Simpson Paul R. Austin 《The Journal of experimental medicine》1933,57(6):897-906
The increased gonadotropic effect obtained by combining prolan with hypophyseal extracts can be secured equally well by the use of preparations which contain high amounts of the growth or of the gonad-stimulating hormone. In hypophyseal extracts containing the growth hormone, the synergistic effects do not parallel the content of growth-promoting substance. Similarly, in hypophyseal extracts containing the gonad-stimulating hormone, the synergistic effects do not parallel the content in the gonadotropic factor. The hypophyseal substance involved has been prepared sufficiently free of the growth and gonad-stimulating hormones to make it inadmissible to consider either of these substances as responsible for the reaction. 相似文献
82.
1. Dakin''s hypochlorite solution has the power of dissolving necrotic tissue, pus, and plasma clot in the concentration and reaction used clinically. 2. Chloramine-T and dichloramine-T do not exhibit this action. 3. The solvent action of Dakin''s hypochlorite solution of the degree of alkalinity used clinically is due primarily to its hypochlorite content, but its slight alkalinity, while in itself without solvent action, enhances the effectiveness of the hypochlorite. 4. In the degree of alkalinity used clinically, the solvent action of hypochlorite is absent below about 0.2 per cent sodium hypochlorite concentration. 5. The hypochlorite concentration at which the solvent action ceases is lower the more alkaline the solution, and vice versa. 6. None of the antiseptics studied had demonstrable solvent action on blood clot. 相似文献
83.
These experiments indicate, therefore, that when hemoglobin is set free in the portal circulation a larger amount is held by the liver and converted rapidly into bile pigment than is the case when it is set free in the general circulation, and that, under the former condition, over-loading of the liver with bile pigment more readily occurs and jaundice is more apt to develop. This mechanical influence must, therefore, be a factor in the lessened tendency after splenctomy to the jaundice which follows blood destruction due to hemolytic agents, for whether the spleen be an active factor in destroying the erythrocytes or whether it plays merely a passive part as a place for the deposition of the disintegrating cells, there can be no question that in this organ, when it is present, a large number of cells undergo their final disintegration after the action of hemolytic poisons, and that the hemoglobin there liberated passes by the portal system directly to the liver. When the spleen is removed, this disintegration occurs in other organs, notably in the lymph nodes and bone marrow, and the hemoglobin from these organs passes not into the portal but into the general circulation, from which it reaches the liver more gradually and in a more dilute form. 相似文献
84.
In a large proportion of dogs that have been splenectomized for periods of two weeks or more, one finds a great increase in the number of endothelial cells of the lymph nodes. In most splenectomized dogs that succumb to an injection of hemolytic immune serum within forty-eight hours, the sinuses of the lymph nodes contain large numbers of endothelial cells, phagocytic for red cells. This is not seen in normal dogs receiving hemolytic serum. Likewise a similar power of phagocytosis is seen frequently in the stellate cells of the capillaries of the liver. Both in the lymph nodes and the liver these cells appear to be formed in situ; we find no evidence that they have been transported to these organs. Such findings suggest the development of a compensatory function on the part of the lymph nodes and possibly of the liver. Normally the spleen contains cells which have the power to engulf and presumably to destroy the red blood corpuscles. In certain pathological conditions this function is frequently greatly augmented and may sometimes be shared by the lymph nodes, for example, in typhoid fever, as was first clearly shown by Mallory. Our observations suggest that in the absence of the spleen, this function of forming red blood corpuscle-phagocyting cells, normally a minor activity of the lymph nodes, becomes highly developed in the latter organs, and that these cells, and the stellate cells of the liver, thus assume, in part at least, the function of destroying red blood corpuscles by phagocytosis. In view of the somewhat limited material at our disposal, we offer this, not as definitely conclusive, but as evidence which, in connection with the work of others, is highly suggestive of the possibility of the lymph nodes assuming some of the function of the spleen. Whether this activity of the endothelial cells of the lymph nodes and the liver has any bearing on the anemia that follows splenectomy and on the occurrence of spontaneous jaundice in the late periods after splenectomy, is not yet clear. 相似文献
85.
Jessica M. Franklin Wesley Eddings Peter C. Austin Elizabeth A. Stuart Sebastian Schneeweiss 《Statistics in medicine》2017,36(12):1946-1963
Nonrandomized studies of treatments from electronic healthcare databases are critical for producing the evidence necessary to making informed treatment decisions, but often rely on comparing rates of events observed in a small number of patients. In addition, studies constructed from electronic healthcare databases, for example, administrative claims data, often adjust for many, possibly hundreds, of potential confounders. Despite the importance of maximizing efficiency when there are many confounders and few observed outcome events, there has been relatively little research on the relative performance of different propensity score methods in this context. In this paper, we compare a wide variety of propensity‐based estimators of the marginal relative risk. In contrast to prior research that has focused on specific statistical methods in isolation of other analytic choices, we instead consider a method to be defined by the complete multistep process from propensity score modeling to final treatment effect estimation. Propensity score model estimation methods considered include ordinary logistic regression, Bayesian logistic regression, lasso, and boosted regression trees. Methods for utilizing the propensity score include pair matching, full matching, decile strata, fine strata, regression adjustment using one or two nonlinear splines, inverse propensity weighting, and matching weights. We evaluate methods via a ‘plasmode’ simulation study, which creates simulated datasets on the basis of a real cohort study of two treatments constructed from administrative claims data. Our results suggest that regression adjustment and matching weights, regardless of the propensity score model estimation method, provide lower bias and mean squared error in the context of rare binary outcomes. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
86.
From March 2020 through May 2021, nightlife venues were shut down and large gatherings were deemed illegal in New York City (NYC) due to COVID-19. This study sought to determine the extent of risky party attendance during the COVID-19 shutdown among people who attend electronic dance music parties in NYC. During the first four months that venues were permitted to reopen (June through September 2021), time–space sampling was used to survey adults (n = 278) about their party attendance during the first year of the shutdown (March 2020–March 2021). We examined prevalence and correlates of attendance and mask-wearing at such parties. A total of 43.9% attended private parties with more than 10 people, 27.3% attended nightclubs, and 20.5% attended other parties such as raves. Among those who attended any, 32.3% never wore a mask and 19.3% reported attending parties in which no one wore a mask. Past-year ecstasy use was associated with increased risk for attending private (aPR = 1.51, 95% CI: 1.00–2.28) or other parties (aPR = 2.75, 95% CI: 1.48–5.13), and use of 2C series drugs was associated with increased risk for attending nightclubs (aPR = 2.67, 95% CI: 1.24–5.77) or other parties (aPR = 2.50, 95% CI: 1.06–5.87). Attending >10 parties was associated with increased risk for never wearing a mask (aPR = 2.74, 95% CI: 1.11–6.75) and for no other attendees wearing masks (aPR = 4.22, 95% CI: 1.26–14.07). Illegal dance parties continued in NYC during the COVID-19 shutdown. Prevention and harm reduction efforts to mitigate risk of COVID-19 transmission during such shutdowns are sorely needed. 相似文献
87.
88.
89.
Cynthia R. Whitehead Brian D. Hodges Zubin Austin 《Advances in health sciences education : theory and practice》2013,18(4):755-768
Medical educators aim to train physicians with sound scientific knowledge, expert clinical skills and an ability to work effectively with patients, colleagues and health systems. Over the past century, educators have devoted considerable thought and effort to how medical education might be improved. Analysing the language used to describe these initiatives provides insight into assumptions and practices. The authors conducted a Foucauldian critical discourse analysis of prominent recurrent themes in the North American medical education literature. The assembled archive of texts included works of Abraham Flexner, articles from the journal Academic Medicine (including its predecessor journals) and major medical education reports. A series of recurring themes were identified, including the need to avoid over-specialization, the importance of generalism, and the need to broaden criteria for medical student selection. Analysis of these recurring themes allowed identification of a prominent and recurrent discourse of ‘new.’ This discourse places focus on the future, ignores the ongoing historical nature of issues, suggests a sense of urgency and enables the proposal of modest solutions. It emphasizes changes for individual future doctors, thereby limiting consideration of institutional and systemic factors. Using the image of a carousel, the regular return of themes can be seen as carousel ponies circling around repeatedly in medical education. Identification of this medical education carousel provides an opportunity for medical educators to understand the historical nature of calls for change, and to consider what kinds of reform might be required if they wish to avoid this repetition in the future. 相似文献
90.
Single adolescent girls aged 13-19 years participated in pilot (n=40) and follow up (n=164) studies to develop the reliability and validity of the Loss Response List (LRL). The LRL measures physical, emotional, social, and cognitive grief responses by comparing groups based on pregnancy status (never pregnant, pregnant, perinatal loss, and perinatal loss and pregnant). The pilot study revealed significant results on emotional, social, and cognitive grief responses between the perinatal loss and no-perinatal loss groups. Follow-up study results indicated significant differences between the perinatal loss group and the other groups on grief subscales. Significant differences also occurred between perinatal loss and never pregnant groups on depression. The LRL should be useful in gathering information about adolescent grief responses, including perinatal loss. 相似文献