Risk factors for a medically inappropriate admission to a Department of Internal Medicine

OBJECTIVE: To identify patient- and admission-related risk factors for a medically inappropriate admission to a department of internal medicine. METHODS: Cross-sectional study of a systematic sample of 500 admissions to the department of internal medicine of an urban teaching hospital. The appropriateness of each admission and reasons for inappropriate admissions were assessed using the Appropriateness Evaluation Protocol. Risk factors included the time (day of week and holidays) and manner (through emergency department or direct admission) of admission, patient age and sex, health status of patient and spouse, living arrangements, formal home care services, and informal support from family or friends. RESULTS: Overall, 76 (15.2%) hospital admissions were rated as medically inappropriate by the Appropriateness Evaluation Protocol. In multivariate analysis, the likelihood of an inappropriate admission was increased by better physical functioning of the patient (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.1-2.1 [for 1 SD in Physical Functioning scores]), lower mental health status of the patient's spouse (OR, 2.6; 95% CI, 1.3-5.6), receipt of informal help from family or friends (OR, 3.3; 95% CI, 1.5-7.2), and hospitalization by one's physician (OR, 3.6; 95% CI, 1.7-7.5). Receiving formal adult home care was not associated with inappropriateness of hospitalization. CONCLUSIONS: Inappropriate admissions to internal medicine wards are determined by a mix of factors, including the patient's health and social environment. In addition, the private practitioners' discretionary ability to hospitalize their patients directly may also favor medically inappropriate admissions.     

Improved modulation techniques for PWM-VSI drives

PWM-VSI based AC motor drives have two main problems. The inverter is nonlinear which causes instability problems in some specific working points of the AC machine and it emits acoustic noise due to the switching frequency. Nonlinearities like dead-time in the inverter, load dependent DC-link voltage ripple and the voltage drop across the switches are modeled and compensated by improved modulation techniques in order to obtain an almost ideal inverter. Different feedback and feedforward techniques are proposed. The acoustic noise is reduced by using a random modulation strategy. Measurements show a significant improvement by using feedforward and feedback techniques for linearizing the inverter. An improvement in reduction of the acoustic noise emission is also achieved by using random modulation. It is concluded that a combination of a random modulation strategy and feedforward/feedback techniques gives an almost ideal AC motor drive system     

Contraindications to metformin therapy in patients with NIDDM

OBJECTIVE: Treatment with metformin is occasionally associated with the development of severe lactic acidosis. However, this is usually observed in patients with major contraindications to the drug. In this study, we aimed to determine the prevalence of conditions currently regarded as either contraindications or cautions to the use of metformin in patients with NIDDM. RESEARCH DESIGN AND METHODS: The case notes of metformin-treated NIDDM patients (mean age 62 years) attending a United Kingdom university hospital diabetes clinic over a 3-month period were reviewed according to criteria reflecting a pragmatic view of current prescribing recommendations. RESULTS: Of 89 consecutive patients whose notes could be evaluated in detail, only 41 (46%) had no contraindications or cautions to metformin whatsoever. Concomitant chronic disorders associated with a potentially increased risk of hyperlactatemia were renal impairment (n = 2; plasma creatinine concentrations 1.7 and 2.3 mg/dl, respectively), cardiac failure (n = 2), and chronic liver disease (n = 2). Other potentially relevant disorders included ischemic heart disease (n = 20), clinical proteinuria (n = 14), peripheral vascular disease (n = 22), and pulmonary disease (n = 7). Multiple conditions (i.e., two, three, or four) were present in eight, five, and one patient(s), respectively. CONCLUSIONS: More than half the patients in our series had concomitant conditions or complications conventionally regarded as cautions or contraindications to metformin; approximately 10% had a multiplicity of such conditions. Regular surveillance is necessary to detect the development of complications such as renal impairment. Vigilance is also required in view of the increased risk of major intercurrent illnesses, which may independently disturb lactate metabolism in patients with NIDDM. Metformin should be withdrawn promptly under such circumstances.     

Frontiers in research on cystic fibrosis: understanding its molecular and chemical basis and relationship to the pathogenesis of the disease

In recent years a new family of transport proteins called ABC transporters has emerged. One member of this novel family, called CFTR (cystic fibrosis transmembrane conductance regulator), has received special attention because of its association with the disease cystic fibrosis (CF). This is an inherited disorder affecting about 1 in 2000 Caucasians by impairing epithelial ion transport, particularly that of chloride. Death may occur in severe cases because of chronic lung infections, especially by Pseudomonas aeruginosa, which cause a slow decline in pulmonary function. The prospects of ameliorating the symptoms of CF and even curing the disease were greatly heightened in 1989 following the cloning of the CFTR gene and the discovery that the mutation (deltaF508), which causes most cases of CF, is localized within a putative ATP binding/ATP hydrolysis domain. The purpose of this introductory review in this minireview series is to summarize what we and others have learned during the past eight years about the structure and function of the first nucleotide binding domain (NBF1 or NBD1) of the CFTR protein and the effect thereon of disease-causing mutations. The relationship of these new findings to the pathogenesis of CF is also discussed.     

Cardiac risk in surgery. A review and guidelines for risk evaluation and reduction of cardiac risk in general surgery

We report herein the phenotypic and functional analysis of human bone marrow and thymus derived early T cells. Commitment to T cell lineage is acquired during CD7 antigen expression by CD34+ precursors in human bone marrow and before thymus colonization. Early thymocytes show similar phenotypic characteristics as bone marrow T cells. They rapidly acquire CD4 before the dual expression of CD4 and CD8. Their expansion and differentiation is regulated by two major factors: thymic stroma and cytokines produced by these stroma cells or by thymocytes themselves. Among cytokines, IL1 and sCD23 produced by thymic epithelial cells support in vitro early T cell development.     

Excited-state-absorption cross sections and amplifier modeling inthe 1300-nm region for Nd-doped glasses

The performance of Nd³⁺-doped fibre amplifiers is limited by strong excited-state absorption (ESA) of the signal, and, even for fluorozirconate glasses, ESA prevents the important region below 1320 nm from being used. To quantify this limitation and explore alternative host materials, ESA and stimulated-emission cross sections have been measured for a representative group of glass compositions. These parameters have been used in an accurate fiber-amplifier model to provide the first quantitative comparisons of performance for Nd³⁺ -doped glasses in the 1300-nm band as a function of host     

In situ bypass and diabetes

From 1986 through to 1990 a total of 483 in situ bypass procedures were performed in 444 patients. Preoperative risk-factors were equally distributed among diabetic (DM) and non-diabetic (NDM) patients, except for smoking habits (DM:48%, NDM:64%, p = 0.002) and cardiac disease (DM:45%, NDM:29%, p = 0.005). Critical limb-ischaemia was more often present in diabetic than non-diabetic patients (DM:57%, NDM:36%, p = 0.0002). Diabetic patients had a significantly lower distal anastomosis than non-diabetic patients (p = 0.00001). There were no differences among diabetic and non-diabetic patients regarding three years primary and secondary patency (58% and 64% respectively), and regarding major amputations. However, the rate of minor amputations was higher in insulin-dependent compared with non-insulin-dependent diabetics, who in turn had a higher rate than non-diabetics (p < 0.00001). A markedly decreased survival rate was found in diabetics (p < 0.00005). We found the in situ bypass technique very useful in the treatment of critical ischaemia of the lower limb in diabetic patients. The overall results in diabetic patients, whether insulin-dependent or not, were equal to those in non-diabetic patients.     

Room electromagnetics

In analogy with the established discipline of room acoustics, various aspects of diffuse wideband microwave propagation in a room are treated. It is shown that an equivalent to Sabine's equation for reverberation time in a room is valid for the completely diffused field, depending only on the volume, the surface area, and an effective absorption coefficient. An exponential decay of the power as a function of the delay is a consequence of the assumptions. Furthermore, the concept of a reverberation distance is also valid. This is the distance from a transmitting antenna where the received diffuse, randomly scattered power equals the direct line-of-sight received power, such that the diffuse power dominates for distances larger than the reverberation distance. A number of measurements in a large room support the theory with an effective absorption coefficient of 0.5. The power delay profiles around the room from a transmitter in the ceiling vary only in the first arriving part of the impulse, whereas the tail, being dominated by the diffuse field, has the same power level for a given delay and the same decay rate all over the room. It is also a consequence of the theory that the diffuse fields incident on an antenna are uniformly distributed in angle.     

Human granulocytes contain an opiate alkaloid-selective receptor mediating inhibition of cytokine-induced activation and chemotaxis

Human peripheral blood granulocytes previously were found to contain opioid delta 2-receptors mediating stimulation by opioid peptides of chemotaxis. Studies presented in this work indicate that granulocytes also contain opiate alkaloid-selective, opioid peptide-insensitive receptors mediating inhibition by morphine and other opiates of cytokine-induced activation and chemotaxis. Binding studies with [3H]morphine and [3H]diprenorphine ([3H]DPN) indicated the presence of receptor sites, at considerable density with affinities and selectivity for opiates comparable with those of the mu 3-receptor of human peripheral blood monocytes (macrophages). The influence of the guanosine 5'-triphosphate (GTP) analogue GppNHp on binding indicated that the granulocyte receptor was linked to a G protein. Morphine but not opioid peptides interfered with activation and/or chemotaxis of the granulocytes induced by TNF-alpha, IL-1 alpha, IL-8, and FMLP (chemotactic peptide). These effects of morphine were blocked by the antagonist naloxone. Levorphanol inhibited TNF-alpha-induced activation, and also potentiated the inhibition by morphine. Furthermore, in binding assays, levorphanol enhanced the affinity of the receptor for morphine. Dextrorphan had no effect on activation or chemotaxis, and it also had no effect on binding, indicative of stereoselectivity for the effect of levorphanol. It is concluded that human granulocytes contain opiate alkaloid-selective mu 3-receptors that mediate inhibitory effects of morphine on cellular activation by cytokines.     

三相异步电动机可靠性和经济分析

根据三相异步电动机的主要失效模型,利用概率分析和补充变量方法,求得了三相异步电动机的可靠性指标和运行的经济指标。