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Biomedical subjects

S Weinstein

Publications and source records attributed to S Weinstein.

At least 55 records · Page 3Linked to original sources
PubMed1996

A model to assess the effectiveness of topical antipruritics.

A model has been developed to determine the effectiveness of topical antipruritics. It utilizes controlled, experimentally induced itch and has demonstrated the effectiveness of the direct action on cutaneous receptor sites of a topical anesthetic, benzocaine, in a topical antipruritic formulation, and has been used to differentiate between two effective topical antipruritics. Three studies are presented: The first study examined the reliability of the experimentally induced itch. Several indices of reliability were computed from the data of this first study. Cronbach's alpha was 0.92. Winer's theta also was 0.92. Simple test-retest reliability, computed at intervals of 29 min, 1 day, and 6-7 days, resulted in Pearson correlations of 0.84, 0.73, and 0.60, respectively. In the second study, the model differentiated statistically between the itch relief resulting from the topical application of a formulation with 6% benzocaine and the same formulation without benzocaine. The third study examined 2 known topical antipruritics: one containing 6% benzocaine and the other 1% hydrocortisone. Both topical antipruritics were found to relieve itch; however, the benzocaine antipruritic produced statistically significantly greater itch relief in more subjects than the hydrocortisone antipruritic at both 1 and 30 min after application. These results demonstrate that OTC antipruritics can be differentiated for effectiveness.

Administration, Topical↗
PubMed1995

The suitability of a monofunctional reagent of an undecagold cluster for phasing data collected from the large ribosomal subunits from Bacillus stearothermophilus.

An electron density map of the large ribosomal subunit from Bacillus stearothermophilus was obtained at 26 A resolution by single isomorphous replacement (SIR) from a derivative formed by specific quantitative labeling with a dense undecagold cluster. For derivatization, a monofunctional reagent of this cluster was bound to a sulfhydryl group of a purified ribosomal protein, which was in turn reconstituted with core particles of a mutant lacking this protein. The native, mutated, and derivatized 50S ribosomal subunits crystallize under the same conditions in the same space group. Under favorable conditions, crystals of the derivatized subunit proved to be isomorphous with the native ones, whereas the crystals of the mutant may have somewhat different packing. After resolving the SIR phase ambiguity by solvent flattening, the electron density shows a packing that is consistent with the noncrystallographic symmetry found by Patterson searches as well as with the motif observed in electron micrographs of thin sections of the crystals. These studies established that phase information can be obtained from heavy metal clusters, even when the crystals under investigation are unstable and weakly diffracting. These results encouraged further effort at the construction of specifically derivatized crystals from other ribosomal particles that diffract to higher resolution.

Crystallography, X-Ray↗
PubMed1995

Isolated sigmoid tuberculosis. Report of a case.

PURPOSE: To heighten awareness of colonic tuberculosis (TB) as a once rare disease that is undergoing a resurgence in the United States. METHODS: Report of a case of isolated sigmoid tuberculosis with a brief literature review of the topic. RESULTS: TB can no longer be considered a rare disease in the United States because, in part, of the acquired immunodeficiency syndrome epidemic and because, in part, of increased immigration and lack of containment. The signs and symptoms of colonic TB are nonspecific; therefore, a high index of suspicion must be maintained. Only 20 percent of patients will have associated active pulmonary TB. Colonoscopy with multiple biopsies at ulcer margins should be performed for diagnosis. Tissue should be sent for routine histology and culture and smeared for direct visualization of acid-fast bacilli. If colonic TB is suspected, empiric treatment is warranted, despite negative histology, smear, and culture results. Patients will usually show a dramatic response in one to two weeks. Treatment is solely medical, and all patients should receive a full course of antituberculous chemotherapy. Exploratory laparotomy is necessary if diagnosis is in doubt, when there is concern about a neoplasm, or for complications including perforation, obstruction, hemorrhage, or fistulization. CONCLUSION: An increased awareness of intestinal TB coupled with familiarity of the pathophysiology, diagnostic methods, and treatment should increase the number of cases correctly diagnosed preoperatively and, therefore, improve the outcome of patients with this disease.

Aged↗
PubMed1995

Cholelithiasis in pediatric cardiac transplant patients on cyclosporine.

From June 1984 to June 1993, symptomatic chlolethiasis was observed in six (6.7%) of 90 cases of pediatric heart or heart-lung transplants at the author's institution. The incidence of cholelithiasis for all children under 16 years of age is estimated to be less than 1%. Previously, information on cholelithiasis in pediatric transplant patients on cyclosporine therapy had been limited. Studies concerning the incidence of gallstones in adult kidney and cardiac transplant patients have shown that there is an increase associated with cyclosporine, possibly related to elevated levels and hepatoxicity. Five patients underwent uneventful cholecystectomy. There was only one death, which occurred after emergency cholecysostomy tube placement for biliary sepsis. If indicated, biliary tract surgery can be performed safely in cardiac transplant patients. The authors report on their experience with symptomatic cholelithiasis in pediatric cardiac transplant patients and review the current literature on the hepatotoxic effects of cyclosporine.

Adolescent↗
PubMed1995

FDG-PET in children and adolescents with partial seizures: role in epilepsy surgery evaluation.

We used FDG-PET to measure interictal glucose metabolism in 16 children and adolescents (mean age 14.7 years) and complex partial seizures (CPS) (mean seizure onset age 5.0 years). Video-EEG localized the epileptic foci. Glucose metabolism was determined in 14 paired anatomic areas using a standard template. PET hypometabolism was defined as greater than 15% asymmetry. Nine of the 13 (69%) patients with a unilateral EEG focus had regional hypometabolism ipsilateral to the epileptogenic zone. Three subjects had bilateral EEG foci; all had nonfocal PET. MRI (15 patients) concurred with EEG and PET in two, and was normal in seven of nine with focal hypometabolism. One of seven patients with normal PET had a focal MRI abnormality. FDG-PET results are similar to those found in adults, but are present earlier in the natural history of CPS (9.7 vs 22.2 years duration epilepsy) than previously reported. The presence of FDG-PET hypometabolism may be associated with a poor response to drug treatment. PET can identify metabolic abnormalities associated with epileptic foci in children and adolescents and is useful in directing surgical intervention for the control of refractory complex partial epilepsy.

Adolescent↗
PubMed1995

Relationship between the threshold of ovarian sensitivity to human menopausal gonadotrophin stimulation and in-vitro fertilization treatment outcome.

In a retrospective study of 813 oocyte retrieval-embryo transfer cycles in women with normal follicle stimulating hormone and luteinizing hormone concentrations, we sought to investigate the relationship between the amount of human menopausal gonadotrophin (HMG) used for ovarian stimulation and treatment outcome. Patients were divided into three groups: group A patients (495 cycles) required < 40 ampoules of HMG and had a predicted probability for pregnancy of 25% per embryo transfer; group B patients (165 cycles) required 41-77 ampoules per cycle, with a predicted probability rate for pregnancy of 5-25% per embryo transfer; and group C patients (153 cycles) required > 77 ampoules of HMG and the predicted probability for pregnancy was < 5% per embryo transfer. Groups C and A differed significantly (P < 0.005). The mean oestradiol concentration on the day of HCG administration in group C was 6412 pmol/l, and the mean number of eggs retrieved was seven. The highest success rates were found when up to 2.5 ampoules of HMG were required for each egg or 4.4 ampoules for each embryo. The lowest rates were obtained when > 4.8 ampoules of HMG were necessary for each oocyte or > 9.6 ampoules for each embryo (P < 0.005). We identified a group of infertile patients who required excessive amounts of HMG to achieve a fair degree of steroidogenesis, number of eggs and number of embryos but who had very low pregnancy rates. Although all other relevant parameters were normal, this may highlight the beginning of ovarian-gamete insufficiency before the basic hormonal status is affected. In cases of repeated failure, oocyte donation should be considered.

Drug Resistance↗
PubMed1995

Quality in pathology laboratory practice.

Quality refers not only to analytical quality control, a traditional area of laboratory excellence, but to the entire science of quality management. As measures of quality, structural indicators refer to staffing and physical facilities, process indicators to the institutions operations and, perhaps most importantly, outcome indicators address the ultimate patient care uses that pathology information is put to. Comparison of performance to peer laboratories, external quality control, is a practical, if limited, yardstick of performance. Customer satisfaction and turn-around-time of tests are receiving more recent attention as quality measures. Blood banking, because of its inherently complex cycle from donor phlebotomy to product infusion, requires special considerations with regard to quality management. Reporting of anatomical pathology, where the only gold standard is a consensus of experts, also does not lend itself to classical numerical quality assessment.

Autopsy↗
PubMed1995

Structured knowledge representation: an improved methodology for communication of hospital policy.

The optimal operational integrity of a health care facility depends upon the correct interpretation of an adherence to well designed and written policies. Memos describing policy and procedures can be ambiguous, hindering their comprehension rather than helping it. Two alternative methods have been developed for communicating policy: the algorithmic flow chart and a computer decision support program. To determine the best means of communicating policy, the written memo, flow chart, and computer program were compared in scenario presentation interviews. The average time required to complete the test scenarios was five minutes for the traditional memo, two minutes for the algorithm, and two minutes for the computer program. Accuracy improves markedly from the traditional memo to the computer program. ANOVA reveals that the flow chart and computer program are significantly superior to memos as methods for communicating hospital policy.

Algorithms↗
PubMed1994

A strategy to reduce inappropriate red blood cell transfusion.

OBJECTIVE: To evaluate the effectiveness of policies intended to decrease unnecessary packed red cell transfusions. DESIGN AND SETTING: The transfusion records of a 550-bed acute care facility were obtained and two six-month periods, one before and one after the introduction of new transfusion policies, were compared. RESULTS: Meaningful reductions were seen in crossmatch requests, number of units crossmatched and units transfused. After standardising for rising patient numbers, units transfused per 1000 admissions fell by 28.8%. Units crossmatched fell by slightly more than did units transfused, resulting in lower crossmatch-to-transfusion ratios, and indicating more effective use of resources. Total requests fell while "group-and-screen" requests rose, showing a shift toward more appropriate ordering in the face of increasing workload. CONCLUSIONS: The transfusion policies have succeeded in curtailing unnecessary transfusion practices. They included the lowering of "transfusion-triggering" haemoglobin levels, registrar or consultant approval of transfusions and enforcement of patient consent and chart documentation of transfusion indications, verified by the laboratory. The surgical blood ordering schedule was reviewed under the overall direction of the transfusion committee. A strong institutional commitment is required to lift the profile of blood transfusion.

Blood Grouping and Crossmatching↗
PubMed1994

Neuroimaging of brain injury in neonates treated with extracorporeal membrane oxygenation: lessons learned from serial examinations.

The head ultrasound (US) is used extensively at most extracorporeal membrane oxygenation (ECMO) centers to screen for intracranial pathology in the ECMO candidate. Daily head US examinations are obtained in patients on ECMO to detect the emergence of intracranial hemorrhage (ICH). The authors asked whether these serial studies could be correlated with more definitive diagnostic studies, such as computed tomography (CT) and magnetic resonance imaging (MRI) scans, autopsy data, or the long-term neurodevelopmental status, to discern the predictive value of these daily examinations. Seventy-four consecutively treated neonates with reversible respiratory failure refractory to conventional support met institutional criteria for placement on ECMO. In addition to a pre-ECMO US, daily real-time portable head US images were evaluated for changes in echotexture, ventricular configuration, and extraaxial fluid. Follow-up CT and MRI scans were evaluated for the presence of hemorrhagic or ischemic lesions. Autopsy data were obtained from nonsurvivors. Survivors were examined by a neurodevelopmental specialist at regular intervals and classified as normal or delayed for chronological age. In this series of 74 patients, CT/MRI scanning and autopsy data demonstrated structural injury in 19 patients; there were 16 ischemic infarctions and three hemorrhages. The incidence of hemorrhage in this series was considerably lower than that previously reported. Ten of the 19 patients had serial head US findings demonstrating a progression from focal increases in echotexture to diffuse effacement of cerebral architecture. In the remaining nine, serial head US examinations did not show injury. An additional 10 children had a clear delay in neurological development despite no evidence of anatomic injury on serial head US examinations or CT/MRI scanning.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1993

Role of infection control practitioners in human immunodeficiency virus testing. APIC Bloodborne Pathogens Committee.

BACKGROUND: As a result of the HIV epidemic, the role of the ICP has changed; acute care settings have developed a variety of policies regarding patient and health care worker (HCW) HIV testing and issues related to the HIV-infected HCW. APIC conducted a survey to determine the extent to which ICPs were involved in HCW and patient HIV testing and counseling, the prevalence of routine HIV testing for patients, institutional policies on HIV testing of patients and HCWs, and the management of HIV infected HCWs. METHODS: In 1990, a questionnaire was sent to ICPs in a simple random sample of 1300 acute care hospitals (approximately 20%) in the United States. RESULTS: Response rate was 52.8%. Of the 686 respondents, 54.8% provided counseling to the HCW after an exposure incident. ICPs were involved not only in HIV testing and counseling for patients and HCWs but also in institutional policy development for HIV-related issues. Most facilities (73.8%) obtained written consent for testing from the patient after an employee exposure. When a direct care giver was known to be HIV positive, 61.5% of the respondents evaluated each case individually. CONCLUSIONS: The ICP has a significant role in the development and implementation of institutional policies on HIV testing and counseling and on the management of HIV-infected workers. These findings affirm the need for APIC to provide educational opportunities on the issues related to HIV testing and counseling.

AIDS Serodiagnosis↗
PubMed1993

Newborn surgical emergencies. Congenital diaphragmatic hernia and extracorporeal membrane oxygenation.

Bochdalek hernia is a posterolateral defect in the embryogenesis of the diaphragm. Abdominal contents enter the thorax during fetal development and result in pulmonary hypoplasia. A cause of respiratory distress in the newborn, the management of this disease has undergone dramatic changes. The defect requires surgical repair, but success depends more on preoperative and postoperative management of the associated physiologic derangements.

Animals↗