摘要:

Increasing interest in skills training has been prompted by concerns over risks posed by new, complex clinical environments and the need for medical students to function effectively in such settings. To gain a better idea of the type of instruction currently provided to U.S. medical students, a national survey was conducted in 1991. A survey instrument was prepared after a literature review on practical skills training. Eleven skill and knowledge areas were selected for analysis; six were considered “basic” and five “advanced.” Mailings were directed to the deans of 126 U.S. medical schools. Based on a 94% response rate (118/126), the skill and knowledge areas taught most commonly included universal precautions, phlebotomy, intravenous line placement, advanced cardiac life support, and suturing lacerations. Fifty-one (43%) of 118 respondents reported that they conducted “transition courses” for practical skills training. At most such institutions, basic skills were taught more frequently than advanced skills. Where there was no transition course, formal instruction was provided in standing courses and clerkships. The survey indicates that five skill areas are formally taught in the majority of U.S. medical schools. These include universal precautions, phlebotomy, starting intravenous lines, suturing lacerations, and advanced cardiac life support. In most cases, evaluation and certification procedures are infrequent. Further studies are necessary to gain a better idea of what practical training should be undergone by all U.S. medical students.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Expression of the c-myc and c-Haras protooncogenes is dramatically increased in regenerating rat liver as an early response to partial hepatectomy. Nuclear runon transcription studies confirm that the increased c-myc and c-Ha-ras mRNA levels in regenerating livers reflect transcriptional activation of these genes. Mithramycin, a G-C specific DNA binding drug, prevents the increased transcriptional activity of c-myc and c-Ha-ras genes after hepatectomy but does not alter the transcriptional activity of the beta-actin gene. Continuous exposure of rats to mithramycin after hepatectomy prevents the increase in both c-myc and c-Ha-ras expression and blocks the increased cellular proliferation characteristic of regeneration. The delayed increase in c-myc and c-Ha-ras gene expression is associated with a delay in cellular proliferation. The inhibition of c-myc and c-Ha-ras transcription by mithramycin, the delay in cellular proliferation, and the ability of mithramycin to prevent protein binding to the c-myc promoter, suggest that the increased expression of these genes is a necessary component of liver regeneration.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

The effect of SnCl2on the transcription of the heme oxygenase gene in spontaneously hypertensive rats was examined using cDNA for the rat heme oxygenase (HO-1). An increase in renal HO-1 mRNA levels was observed in response to SnCl2treatment. Quantitative evaluation by scanning densitometry demonstrated a maximal increase in HO-1 mRNA 24-fold over control at 8 hours after SnCl2administration. Nuclear runoff assay using isolated renal nuclei from SnCl2-treated rats revealed an active HO-1 gene transcription. Transcription of HO-1 in rat kidney was greatly increased within 3 hours of administration of SnCl2, as evidenced by the level of [α32P]UTP incorporation into nuclear RNA. As a consequence of activation of the HO-1 gene transcription, renal enzyme activity increased eightfold at 16 hours after SnCl2, and reached maximal activity of 16-fold over control at 32 hours after injection. No significant change in cytochrome P450 fatty acid ω-hydroxylase (P450 4A) mRNA was observed after SnCl2administration. Cytochrome P450-arachidonic acid ω/ω-1 hydroxylase(s) activity (formation of 20− and 19-HETE) was significantly reduced 24 hours after SnCl2administration and remained lower than the control level 48 and 72 hours after injection. In addition, blood pressure was reduced from 151 ± 2.5 mm Hg to 133 ± 2.3 mm Hg after 48 hours of SnCl2treatment. The reduction in blood pressure preceded natriuresis. It is concluded that SnCl2induces activation of the HO-1 gene, which is followed by elevation in enzyme activity and a decrease in cytochrome P450-arachidonic acid ω-hydroxylase activity. These biochemical changes bring about a selective decrease in the synthesis of 19-HETE and 20-HETE, arachidonate metabolites with prohypertensive properties, and are associated with blood pressure reduction to normal levels. It is suggested that manipulation of heme oxygenase and cytochrome P450-arachidonic acid ω-hydroxylase expressions may be of therapeutic importance in regulating blood pressure.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Forty-nine calorimetric studies were performed on 24 very low birth weight infants with respiratory distress syndrome on mechanical ventilation during the first seven postnatal days. Mean resting energy expenditure for the entire study was 59 ± 21 kilocalories/kg daily, with a respiratory quotient of 0.93 ± 0.1, reflecting the predominance of carbohydrate calories. A comparison of mean energy intake with mean resting energy expenditure showed a mean caloric deficit of 31 kcal/k daily during the first 4 postnatal days, followed by 3 days where resting energy expenditure was met by equivalent caloric intake. Wide variation was noted in resting energy expenditure.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Over a 5-year period, 110 cardio-verter-defibrillators (109 epicardial, 1 trans-venous) were implanted consecutively in selected patients with ventricular tachyarrhythmias. The perioperative course of this patient population was examined to determine the associated morbidity and mortality of the procedure. Patients were predominantly male, with coronary artery disease and a decreased left ventricular ejection fraction. Most underwent median sternotomy for implantable cardioverter defibrillator implantation. The incidence of perioperative mortality was found to be 2.7%. New-onset atrial fibrillation or flutter occurred in 17.3% of the patients during the postoperative period and aggravation of ventricular tachyarrhythmias in 19.1%. The ICD system became infected in 2.7% of the patients and the mediastinal incision site infected in 2.4%. Pneumonia developed in 4.5%. Other complications included significant blood loss, ICD pocket hematomas, and lead dislodgement. There is an appreciable incidence of morbidity and mortality associated with ICD implantation.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Abnormalities of membrane protein band 4.2 in human red cells are reviewed from the standpoints of clinical hematology, protein chemistry, membrane functions, and gene expression. This article will help more extensive investigations in clarifying the physiologic significance of this protein, and to understand abnormalities of band 4.2 in clinical, biochemical, biologic, and genetic aspects.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Celiac disease is a fascinating illness, from both a clinical and research perspective. Most clinicians consider a diagnosis of celiac disease when a young patient has classic signs and symptoms of steatorrhea and severe mal-absorption. However, the typical gastrointestinal symptoms often are absent. The patient may only have subtle signs of chronic malnutrition or nonspecific gastrointestinal complaints. Celiac disease is not diagnosed commonly in the United States, at least in part because of a low clinical index of suspicion. A diagnosis of celiac disease is confirmed by a small bowel mucosa biopsy. A dramatic clinical response to a gluten-free diet verifies the diagnosis, and provides a cost-effective treatment free of significant side effects. Strict adherence to the prescribed diet usually results in a complete resolution of the symptoms and mucosal histopathologic changes. The serious, long-term complication of intestinal lymphoma also may be prevented. To the clinical investigator, celiac disease is an important model of the HLA-associated immune-mediated illnesses. A specific HLA-DQ heterodimer is found in 95% of patients, representing perhaps the strongest association of any illness with a specific class IIHLA molecule. In addition, an important environmental trigger (gluten) has been identified, providing a unique opportunity to study the interaction of gene products and environmental factors in the pathogenesis of an immune-mediated disease.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

A distinct form of renal disease has been described in patients at various stages of HIV infection that is becoming increasingly important as a cause of morbidity and mortality. Black race and intravenous drug abuse appear to predispose one to its development. The HIV-associated nephropathy is characterized by nephrotic-range proteinuria, rapid progression to end-stage renal disease, a diffuse sclerosing glomerulopathy with significant tubulo interstitial disease seen on light microscopy, and tubuloreticular inclusions seen via electron microscopy. The entity can be separated from heroin-associated nephropathy. The pathogenesis is unclear. Possibilities include direct invasion of the virus, effects of other viruses, genetic factors, immune factors, and multiple growth factors. Not all patients with HIV infection and renal disease have HIV-associated nephropathy. Because of prognostic and therapeutic implications, it is crucial to differentiate these lesions. Some reports suggest a possible beneficial effect of zidovudine therapy, but more study is required. Patient survival is dependent on the stage of HIV infection. Dialysis therapy does not appear to substantially prolong life in most patients with AIDS and irreversible renal failure. Therefore, a number of ethical issues have arisen that deal with medical futility.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Endothelins are vasoactive pep-tides that have been implicated in the development and maintenance of systemic arterial hypertension. The biologic effects of endothelins result from activation of either or both of the two known endothelin receptor subtypes, A and B [ET-R(A) and ET-R(B)], which are present not only in blood vessels but also throughout the cardiovascular and central nervous systems. To investigate the potential role and regulation of myocardial endothelin receptors in hypertension, we examined the expression of ET-R(A) and ET-R(B) receptors in the hearts of normotensive and hypertensive rats. A cDNA probe for the ET-R(A) receptor was obtained by polymerase chain reaction amplification of rat aortic smooth muscle cell mRNA, using degenerate primers specific for intramembrane domains III and VI of G-coupled receptors. Moderate stringency hybridization screening of a rat aortic smooth muscle cell cDNA library yielded a partial clone for the ET-R(B) receptor. These two clones wereusedto examine expression of the ET-R(A) and ET-R(B) receptors in heart, brain, and kidney tissues from Wistar-Kyoto (normotensive), spontaneously hypertensive, salt-hypertensive sensitive, and salt-hypertensive resistant rats by Northern analysis. ET-R(A) and ET-R(B) mRNA were present in the hearts of normal rats. Spontaneously hypertensive rat hearts did not express either ET-R(A) or ET-R(B) mRNA, whereas both salt-hypertensive sensitive and resistant rats fed a high-salt diet expressed both ET-R(A) and ET-R(B) receptor mRNAs. Conversely, in the brain of spontaneously hypertensive rats, mRNAs for both ET-R(A) and ET-R(B) mRNA were present. These observations argue for tissue-specific expression of ET-R(A) and ET-R(B) receptors in spontaneously hypertensive rats, and for differences in endothelin receptor regulation among different models of hypertension in the rat.

ISSN:0002-9629    

出版商:OVID    

年代:1994

数据来源: OVID