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1.
The 215,468 diagnoses recorded in 40,130 autopsies on patients treated at the Los Angeles County General Hospital during the 30 years between 1918 and 1948 were reviewed and tabulated. The primary causes of death as determined by the pathologists in these cases were recorded and the incidence of death from each disease in relation to the number of cases in which each occurred was computed. The age, sex and race distribution of patients examined postmortem and the incidence and fatality rates from various pathological conditions changed greatly during the period, owing to many factors, among them changes in elements of the population served by the hospital, an increasing incidence of older patients, and medical triumph over some formerly formidable diseases.  相似文献   

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The Anesthesia Department at the Los Angeles County Hospital established a Nerve Block Clinic for the purpose of alleviating pain and providing helpful information for diagnosis in a number of diseases.During the first year of operation of this Nerve Block Clinic, over one thousand injections were made. The patients who received the injections were referred to the Nerve Block Clinic by staff members who had been apprised of the services offered.  相似文献   

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In the absence of positive evidence that a single injury can cause cancer, the tendency is growing to award compensation to persons (particularly employees) with cancers alleged to have originated in trauma, even cancers which are generally conceded to be congenital in origin.Experimental attempts to induce cancer through trauma have been unsuccessful or doubtful in result. War-wounded persons, boxers and railroad accident victims have no higher incidence of cancer than other groups.Physicians and others in a position to educate the public should strive to dispel the error that cancer following injury is demonstrably or even probably the cause.  相似文献   

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BackgroundCurrent studies suggest that the beneficial effect of breastfeeding on overweight and obesity may have been largely overestimated. We examined the relationship between >4 months of full breastfeeding and overweight/obesity in children living in Germany.MethodsWe analyzed retrospectively collected data on breastfeeding from children aged 3–17 years who participated in the German Health Interview and Examination Survey for Children and Adolescents (KiGGS baseline study) between 2003 and 2006 (n = 13163). To minimize confounding, we applied propensity score matching and multivariate logistic regression analyses to estimate the effect of breastfeeding on childhood overweight and obesity.ResultsAdjusted analyses of the matched dataset (n = 8034) indicated that children who were breastfed for <4 months had a significant reduction in the odds of overweight (OR 0.81 [95% CI 0.71–0.92]) and obesity (OR 0.75 [95% CI 0.61–0.92]) compared to children who were not breastfed or who were breastfed for a shorter duration. Further analyses stratified by age group showed that the association was strongest in children aged 7–10 years (OR 0.67 [95% CI 0.53–0.84] for overweight and OR 0.56 [95% CI 0.39–0.81] for obesity), while no significant effect could be seen in other age groups.DiscussionOur findings support the hypothesis that breastfeeding does have a beneficial effect on childhood overweight and obesity, although the effect seems to be strongest in children of primary school age.  相似文献   

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A new genus and species Amplectosporangium jiangyouense, is described from the Pingyipu Formation (Siegenian) of the Lower Devonian in Jiangyou district, Sichuan, China. The plant consists of naked dichotomizing erect axes with terminal fertile branch-systems. Sporangia are oval-shaped each with a short stalk and are arranged along the inner side of dichotomized axes in single row. By comparison with other known Devonian plants the genus is considered to represent a new morphological type of early land plants. Based on the theory of the telomic origin of the ovular integument, the plant may represent an early stage in the evolution of integument.  相似文献   

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A review was made of the cases of 93 patients with burns covering more than 20 per cent of the body surface who were treated at the San Francisco City and County Hospital, University of California Service, between 1943 and 1956.The mortality rate increased from 40 per cent during 1943-1947 to 69 per cent during 1952-1956. A significant change in survival time was noted: During 1943-1947, 69 per cent of the deaths occurred within 48 hours of admission; during 1952-1956, only 19 per cent of the deaths occurred within the first 48 hours. In the period 1943-1947 the majority of deaths resulted from shock in the immediate post-burn period; in the later years of the study the major cause of death was infection.No patient more than 50 years of age who had burns of more than 25 per cent of the body surface survived. Only one patient with burns involving more than 45 per cent survived.No patient who had a blood culture positive for bacteria survived. The use of antibiotics had no effect on the incidence of infection. Elderly patients, children and alcoholics were less able to resist the effects of infection.The lowest mortality rate was in the age group of 15 through 35 years.  相似文献   

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Since the 1930s, scientists studying the neurological disease scrapie had assumed that the infectious agent was a virus. By the mid 1960s, however, several unconventional properties had arisen that were difficult to reconcile with the standard viral model. Evidence for nucleic acid within the pathogen was lacking, and some researchers considered the possibility that the infectious agent consisted solely of protein. In 1982, Stanley Prusiner coined the term `prion' to emphasize the agent's proteinaceous nature. This infectious protein hypothesis was denounced by many scientists as `heretical'.This essay asks why the concept of an infectious protein was considered controversial. Some biologists justified their evaluation of this hypothesis on the grounds that an infectious protein contradicted the `central dogma of molecular biology'. Others referred to vague theoretical constraints such as molecular biology's `theoretical structure' or `framework'. Examination of the objections raised by researchers reveals exactly what generalizations were being challenged by a protein model of infection.This two-part survey of scrapie and prion research reaches several conclusions: (1) A theoretical framework is present in molecular biology, exerting its influence in hypothesis formation and evaluation; (2) This framework consists of several related, yet separable, generalizations or `elements', including Francis Crick's Central Dogma and Sequence Hypothesis, plus notions concerning infection, replication, protein synthesis, and protein folding; (3) The term `central dogma' has stretched beyond Crick's original 1958 definition to encompass at least two other `framework elements': replication and protein synthesis; and (4) From the study of scrapie and related diseases, biological information has been delineated into at least two classes: sequential and what I call `conformational'.In Part I of this essay, a brief review of the central dogma, as outlined by both Francis Crick and James Watson, will be given. The developments in scrapie research from 1965 to 1972 will then be traced. This section will summarize many of the puzzling, non-viral-like properties of the scrapie agent. Alternative hypotheses to the viral explanation will also be presented, including early versions of a protein-only hypothesis. Part II of this essay will follow the developments in scrapie and prion research from the mid 1970s through 1991. The growing prominence of a protein-only model of infection will be balanced by continued objections from many researchers to a pathogen devoid of nucleic acid. These objections will help illuminate those generalizations in molecular biology that were indeed challenged by a protein-only model of infection.  相似文献   

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Background & Aim

Vascular plants may reduce episodic ebullition losses of methane (CH4) from peatlands. They transport CH4 to the atmosphere, which may lead to a reduction in pore-water [CH4], bubble formation and release. This effect may be compounded by rhizospheric oxidation and associated methanotrophy. However, any reduction in pore-water [CH4] may be countered by root exudation (substrate for methanogens). The aim of this study was to determine how the presence of sedges affects CH4 emissions from peatlands.

Methods

Five pairs of peat cores were collected from a raised bog. One of each pair contained Sphagnum cuspidatum and Eriophorum angustifolium (‘sedge’ cores); the other was dominated by S. cuspidatum (‘no-sedge’). From these the total CH4 efflux—including that due to episodic ebullition—were measured. A partial-shading treatment helped isolate the potential effect of root exudation.

Results

Sedge samples had significantly higher CH4 fluxes than no-sedge samples, but episodic-ebullition fluxes were not significantly different. Between full-light and partially-shaded conditions, there was a significant increase in the difference in CH4 fluxes between the sedge and no-sedge cores.

Conclusion

The higher rates of CH4 flux from the sedge cores cannot be explained simply by higher rates of CH4 production due to rapid utilisation of exudates.  相似文献   

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A prospective study of cardiovascular disease was initiated in 1946 whereby 3983 healthy North American males, 91% under age 40, were subjected to periodic electrocardiograms and medical examinations between 1948 and 1963. The health of all but five of the 3773 survivors was known in 1963. There were 210 deaths: aircraft accidents accounted for 45%, cardiovascular disease 20%, cancer 11% and other causes 23%. The aggregate mortality closely resembled that of the Canadian Life Table 1955-57 (Male). Extra deaths were observed under age 40 owing to a high frequency of flying accidents. At older ages the mortality was lower than expected because congenital and chronic diseases were excluded at entry. One hundred and forty-three developed coronary heart disease. The case fatality rate was 31%. The incidence rate for coronary heart disease rose progressively from 0.277 per thousand per year for ages 25-34 to 26.5 at ages 60-69.  相似文献   

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