共查询到20条相似文献,搜索用时 15 毫秒
1.
J van Gool 《Canadian Metallurgical Quarterly》1976,120(35):1477-1480
2.
A nonconcurrent prospective study was done on the relationship between a number of variables and the progression to AIDS among persons diagnosed with the human immunodeficiency virus (HIV). The variables included sociodemographic ones, behavioral ones, and, most importantly, those persons' difficulties in obtaining public health services for HIV/AIDS. The course of the infection was monitored from the first to the last visit to the health services by means of an individual, diagnostic-based classification, using categories established in 1993 by the Centers for Disease Control and Prevention of the United States of America. Participating in the study were 758 patients seen between 1989 and 1992 in the public AIDS referral services of the city of Belo Horizonte (Minas Gerais). All the persons had been diagnosed with HIV and classified in a pre-AIDS stage. Both the patients who developed AIDS during the study as well as those who did not were assessed according to the selected study characteristics. During the study period, 39.5% of the patients developed AIDS. For the group as a whole, the median time without AIDS was 32.4 months. Multivariate analysis showed that the patients who had less risk of developing AIDS were those who had had fewer than 8.8 medical consultations per year (relative risk = 0.36; 95% confidence interval, 0.26 to 0.50) and an interval of at least 6 months between consultations (RR = 0.37; 95% CI, 0.25 to 0.55). The risk was greater in patients age 30 and older (RR = 1.37; 95% CI, 1.03 to 1.84), in those who were not treated with zidovudine (AZT) (RR = 1.91; 95% CI, 1.37 to 2.64), and those who were initially classified in stage "B" of the disease (RR = 4.83; 95% CI, 3.59 to 6.48). The results of this investigation show the dynamics of the supply and demand of services by these patients, and the information will be useful in planning and organizing care for persons with HIV. Recommendations include giving priority to early intervention with a focus on ongoing outpatient care, and more study of the process that persons with HIV follow in seeking and obtaining health care. 相似文献
3.
4.
PURPOSE: To determine the reason that one-quarter to one-third of epileptic women experienced an increased number of seizures during pregnancy. The cause of this increase is not always clearly understood and the principle emphasis of the literature is on the pregnancy-associated changes of anticonvulsant pharmacokinetics. METHODS: Two patients presented with recurrent seizures occurring only during pregnancy. Both had MRI findings typical of cavernous angiomas of the temporal lobe. RESULTS: In addition to changes in anticonvulsant pharmacokinetics, potential mechanisms underlying the exacerbation of seizures from a vascular malformation during pregnancy include effects of estrogen on temporal structures critically involved in epileptogenesis and changes within the malformation itself secondary to direct actions of estrogen and the hemodynamic changes of pregnancy. CONCLUSIONS: The possibility of an occult lesion such as cavernous angioma should be considered for seizures occurring during pregnancy. Even in the presence of a normal CT scan, an MRI investigation should be pursued, despite the ill-defined fears of MRI in pregnancy. 相似文献
5.
6.
7.
K Arakawa 《Canadian Metallurgical Quarterly》1993,15(6):1171-1179
A sedentary lifestyle may be a risk for hypertension, according to the results of both cross sectional and longitudinal studies. However, exercise may reverse the adverse effects of lack of activity. Many controlled studies have shown that exercise lowers systolic/diastolic blood pressure by at least 10/5 mmHg. Exercise not only improves blood pressure, but also attenuates other risk factors for cardiovascular complications. Dynamic isotonic exercise (e.g., weight lifting). Milder (e.g., brisk walking for 30-60 minutes/day) rather than moderate to severe exercise (e.g., running) is also recommended because of similar effectiveness and better compliance. The underlying mechanism of action of exercise on blood pressure seems to be multifactorial involving a decrease in pressor factors such as plasma norepinephrine, the serum Na/K ratio, endogenous ouabain-like substance and erythrocyte mean corpuscular volume, as well as an increase in depressor factors such as plasma prostaglandin E, serum taurine and urinary dopamine excretion. 相似文献
8.
9.
We have investigated the mechanism and the evolutionary pathway of protein dimerization through analysis of experimental structures of dimers. We propose that the evolution of dimers may have multiple pathways, including (1) formation of a functional dimer directly without going through an ancestor monomer, (2) formation of a stable monomer as an intermediate followed by mutations of its surface residues, and (3), a domain swapping mechanism, replacing one segment in a monomer by an equivalent segment from an identical chain in the dimer. Some of the dimers which are governed by a domain swapping mechanism may have evolved at an earlier stage of evolution via the second mechanism. Here, we follow the theory that the kinetic pathway reflects the evolutionary pathway. We analyze the structure-kinetics-evolution relationship for a collection of symmetric homodimers classified into three groups: (1) 14 dimers, which were referred to as domain swapping dimers in the literature; (2) nine 2-state dimers, which have no measurable intermediates in equilibrium denaturation; and (3), eight 3-state dimers, which have stable intermediates in equilibrium denaturation. The analysis consists of the following stages: (i) The dimer is divided into two structural units, which have twofold symmetry. Each unit contains a contiguous segment from one polypeptide chain of the dimer, and its complementary contiguous segment from the other chain. (ii) The division is repeated progressively, with different combinations of the two segments in each unit. (iii) The coefficient of compactness is calculated for the units in all divisions. The coefficients obtained for different cuttings of a dimer form a compactness profile. The profile probes the structural organization of the two chains in a dimer and the stability of the monomeric state. We describe the features of the compactness profiles in each of the three dimer groups. The profiles identify the swapping segments in domain swapping dimers, and can usually predict whether a dimer has domain swapping. The kinetics of dimerization indicates that some dimers which have been assigned in the literature as domain swapping cases, dimerize through the 2-state kinetics, rather than through swapping segments of performed monomers. The compactness profiles indicate a wide spectrum in the kinetics of dimerization: dimers having no intermediate stable monomers; dimers having an intermediate with a stable monomer structure; and dimers having an intermediate with a stable structure in part of the monomer. These correspond to the multiple evolutionary pathways for dimer formation. The evolutionary mechanisms proposed here for dimers are applicable to other oligomers as well. 相似文献
10.
11.
ED Frohlich 《Canadian Metallurgical Quarterly》1998,13(5):295-297
Chemotherapeutic agents administered to the mother during pregnancy may severely jeopardize the fetus. We describe a newborn girl who had been exposed to idarubicin and cytosine-arabinoside during the second and third trimesters of pregnancy due to treatment of newly diagnosed acute myeloid leukemia in the mother. The child had no structural congenital abnormalities. Adverse effects observed were prematurity, growth retardation, mildly disturbed transaminases and erythroblastosis, all of which were self-limiting with no permanent sequelae. 相似文献
12.
A 67-year-old adult male with borderline hypertension who had extracapsular cataract extraction under general anaesthesia is reported. There were marked fluctuations in his arterial blood pressure following induction of anaesthesia and during the recovery period. He developed a stroke in the immediate postoperative period but was fully recovered after 3 weeks. This case illustrates some of the potentially preventable factors that can predispose to stroke in undiagnosed or poorly controlled hypertensive patients. Such cases are commonly presented to anaesthetists in developing countries where the availability of monitoring equipments, anaesthetic drugs and agents is highly limited. 相似文献
13.
Hypertension is a major risk factor for cardiovascular-related morbidity and death. Antihypertensive therapy markedly reduces the risk caused by elevated blood pressure. Earlier treatment of hypertensive patients should reduce deaths and morbidity even further. The obstetrician-gynecologist has the opportunity and responsibility to identify hypertensive patients early in the course of their disease. He must also confront the problem of elevated blood pressure associated with the use of oral contraceptives. In addition to its impact on the general population, chronic hypertension presents special problems during pregnancy. Pregnant women with elevated blood pressure have an increased fetal mortality rate and develop pre-eclampsia more frequently and earlier than nonhypertensive women. Antihypertensive treatment possibly increases fetal survival; when used appropriately, it definitely does not decrease fetal salvage. The appropriate use of antihypertensive therapy during pregnancy requires an understanding of the mechanism of action of these agents and recognition of side effects, especially those important during pregnancy. 相似文献
14.
15.
Non insulin dependent diabetes mellitus (NIDDM) and obesity are defined as classical insulin resistant states. Essential hypertension is now also considered to be an insulin resistant state, even in absence of NIDDM or obesity, as shown in epidemiological, clinical and experimental studies. Neither the underlying mechanism nor a direct causality between the two phenomena has been detected as yet, but different hypotheses have been postulated where, on the one hand, insulin resistance and hypertension are considered to be causally related and, on the other hand, they are considered to be parallel phenomena due to genetic and acquired factors. The clarification of the connection between hypertension and insulin resistance seems to be of great clinical importance, since they are both independent risk factors for cardiovascular disease and mortality from cardiovascular complications. This paper gives an overview of the results of recent research on the possible underlying pathogenetic mechanisms linking hypertension and insulin resistance. 相似文献
16.
The treatment of chronic, nonhealing wounds is discussed. The authors have successfully utilized locally acting growth factors as an adjunct to aggressive, comprehensive management in a clinical setting. At the Holmes Regional Wound Care Center, wounds with an average duration of 75 weeks at presentation were 100% epithelialized in an average of 10 weeks of therapy. The use of topical PROCUREN, or autologous platelet-derived wound healing factors (PDWHF) is introduced to the podiatric literature. 相似文献
17.
OBJECTIVE: To review current literature regarding the development of hypertensive renal disease, its epidemiology, and its pathophysiology. This review focuses on strategies to slow or halt the progression of endstage renal disease (ESRD) in hypertension, including the role of blood pressure control, different types of antihypertensive agents, early treatment, and dietary considerations. DATA SOURCES: Information was retrieved from searching the MEDLINE database for articles consisting of epidemiologic studies, clinical studies, and review articles pertaining to hypertension and ESRD. Information also was obtained from the US Renal Data System annual data reports. STUDY SELECTION: Emphasis was placed on clinical trials in the English language addressing issues in hypertension and ESRD. Clinical trials reporting relationships between blood pressure control and ESRD, as well as those comparing different antihypertensive agents, were evaluated. DATA EXTRACTION: The methodology and results from clinical trials were evaluated. Studies were assessed according to the measures of renal function used, baseline data collected, degree of blood pressure control, and antihypertensive therapy. DATA SYNTHESIS: Clinical trials including patients with essential hypertension, diabetes mellitus, and renal insufficiency of various etiologies were evaluated. The recommendations from these evaluations were based on study design and the types of populations used (i.e., blacks vs. whites, diabetics vs. nondiabetics). CONCLUSIONS: Blood pressure control is currently the most important strategy to slow or halt the progression of renal insufficiency in hypertensive individuals. Whether specific antihypertensives are renal protective is still controversial, but results from clinical trials are promising. 相似文献
18.
P Hamet Z Pausova V Adarichev K Adaricheva J Tremblay 《Canadian Metallurgical Quarterly》1998,16(4):397-418
Hypertension can be classified as either Mendelian hypertension or essential hypertension, on the basis of the mode of inheritance. The Mendelian forms of hypertension develop as a result of a single gene defect, and as such are inherited in a simple Mendelian manner. In contrast, essential hypertension occurs as a consequence of a complex interplay of a number of genetic alterations and environmental factors, and therefore does not follow a clear pattern of inheritance, but exhibits familial aggregation of cases. In this review, we discuss recent advances in understanding the pathogenesis of both types of hypertension. We review the causal gene defects identified in several monogenic forms of hypertension, and we discuss their possible relevance to the development of essential hypertension. We describe the current approaches to identifying the genetic determinants of human essential hypertension and rat genetic models of hypertension, and summarise the results obtained to date using these methods. Finally, we discuss the significance of environmental factors, such as stress and diet, in the pathogenesis of hypertension, and we describe their interactions with specific hypertension susceptibility genes. 相似文献
19.
Pregnancy may be followed by a postpartum acceleration of renal function loss in patients with renal disease. We retrospectively analyzed the effects of pregnancy on progressive renal function decline, and the risk factors for an acceleration, in a group of 19 renal disease patients with 30 pregnancies and a group of 31 patients who did not become pregnant after onset of glomerular disease. The rate of renal function loss was calculated for each patient by linear regression on reciprocal serum creatinine values over 11 years' follow-up. Multiple regression analysis showed that both pregnancy (P = 0.03) and initial proteinuria (P = 0.005) were independently related with the rate of renal function loss. Such a relation could not be observed with histologic diagnosis, and initial age, renal function, blood pressure, and serum albumin. Further analysis showed that 10 of 30 pregnancies are followed by a predefined acceleration of renal function loss. These pregnancies were preceded and complicated by a higher proteinuria (4.1 v 1.7 g/d, P < 0.005; and 3.6 v 2.1 g/d, P < 0.05, respectively) compared with the other 20 pregnancies that are not followed by such an acceleration. In conclusion, patients with primary glomerular disease complicated by substantial proteinuria are at risk for acceleration of renal function decline after pregnancy. 相似文献
20.