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Biomedical subjects

A R Thomas

Publications and source records attributed to A R Thomas.

11 recordsLinked to original sources
PubMed1999

Transmission of measles virus in healthcare settings during a communitywide outbreak.

OBJECTIVE: To describe the epidemiology of measles in medical settings and to evaluate the implementation and effectiveness of the 1989 Advisory Committee on Immunization Practices (ACIP) guidelines for measles immunization in healthcare workers (HCWs). DESIGN: Confirmed cases of measles reported in Clark County, Washington, from March 14 to June 2, 1996, were analyzed for characteristics of cases occurring in medical settings. A questionnaire was used to assess employee immunization (95% response rate). SETTING AND PARTICIPANTS: Reported measles cases and HCWs at community hospitals, primary-care medical facilities, a health-maintenance organization, and a multispecialty group practice. RESULTS: Of 31 cases of measles, 8 (26%) occurred in HCWs, and 5 (16%) occurred in patients or visitors to medical facilities. Cases of measles occurred in HCWs who were not required to have proof of measles immunity as defined by the 1989 ACIP guidelines. The relative risk of measles in HCWs compared to Clark County adults was 18.6 (95% confidence interval, 7.4-45.8; P<.001). A survey of medical facilities revealed that 47% had an employee measles immunization policy; only 21% met ACIP recommendations and enforced their policies. CONCLUSIONS: HCWs were at higher risk of measles than the adult population. Transmission of measles in medical settings was related to both deficiencies in, and lack of implementation of, the ACIP guidelines.

Adolescent↗
PubMed1999

Development and use of military-unique standardized gynecology patients in military undergraduate medical education.

Performance-based testing using standardized patients is becoming increasingly popular as a means to assess the clinical competence of medical students. Medical students entering postgraduate training in military treatment facilities have the additional responsibility of military readiness. The increasing number of women in the active armed forces and the diverse missions encountered by the military today necessitate inclusion of military-unique standardized gynecologic patients and scenarios into curricula. We developed a military-unique standardized gynecology patient and scenario and an objective structured clinical examination to evaluate medical students' skills in data gathering and synthesis, development of differential diagnoses, problem solving, and working through military-unique issues of the patient scenario. Integration of an objective structured clinical examination of military-unique gynecology standardized patient scenarios into the obstetrics and gynecology curriculum at the Uniformed Services University of the Health Sciences can lead to successful assessment of student clinical skills and provide a means of ongoing military readiness training.

Adult↗
PubMed1998

Coccidioidomycosis: an update.

The incidence of coccidiodomycosis in the southwestern United States has sharply increased over the last decade as a result of environmental and demographic changes. It is important to review the epidemiology, diagnostic indicators, and therapeutic options for both immunocompetent and immunocompromised patients who have a particularly high risk of infection.

AIDS-Related Opportunistic Infections↗
PubMed1998

Ventilation in the patient with unilateral lung disease.

Severe ULD presents a challenge in ventilator management because of the marked asymmetry in the mechanics of the two lungs. The asymmetry may result from significant decreases or increases in the compliance of the involved lung. Traditional ventilator support may fail to produce adequate gas exchange in these situations and has the potential to cause further deterioration. Fortunately, conventional techniques can be safely and effectively applied in the majority of cases without having to resort to less familiar and potentially hazardous forms of support. In those circumstances when conventional ventilation is unsuccessful in restoring adequate gas exchange, lateral positioning and ILV have proved effective at improving and maintaining gas exchange. Controlled trials to guide clinical decision making are lacking. In patients who have processes associated with decreased compliance in the involved lung, lateral positioning may be a simple method of improving gas exchange but is associated with many practical limitations. ILV in these patients is frequently successful when differential PEEP is applied with the higher pressure to the involved lung. In patients in whom the pathology results in distribution of ventilation favoring the involved lung, particularly BPF, ILV can be used to supply adequate support while minimizing flow through the fistula and allowing it to close. The application of these techniques should be undertaken with an understanding of the pathophysiology of the underlying process; the reported experience with these techniques, including indications and successfully applied methods; and the potential problems encountered with their use. Fortunately, these modalities are infrequently required, but they provide a critical means of support when conventional techniques fail.

Humans↗
PubMed1998

Development and use of military-unique standardized gynecology patients for military residents in obstetrics and gynecology training programs.

Focused military curricula and readiness training are often inadequate for military resident physicians. We developed a standardized gynecologic military-unique patient scenario and examination to assess obstetrics and gynecology residents' clinical and operational problem-solving abilities. Integration of military-unique gynecologic standardized patients, clinical scenarios, and objective structured clinical examinations into obstetrics and gynecology curricula is a novel approach for realistic medical readiness training for resident physicians. This tool can become a cornerstone in the ongoing development of needed military-unique curricula.

Clinical Competence↗
PubMed1996

Coccidioidomycosis in patients infected with human immunodeficiency virus: review of 91 cases at a single institution.

We retrospectively evaluated the clinical manifestations, diagnosis, treatment, and outcome of coccidioidomycosis in 91 patients infected with human immunodeficiency virus (HIV) at a single institution. Coccidioidomycosis was the AIDS-defining illness in 37 patients. Fever and chills, weight loss, and night sweats were the most frequent symptoms. The lung was the most frequently involved organ (80%), followed by the meninges (15%). A diffuse reticulonodular infiltrate was seen in 59 patients (65%), and 13 (14%) had focal pulmonary disease; for 15 patients (16%), the chest radiograph was normal. Coccidioidal serologies were positive for 60 patients (68%), while for 23% with proven coccidioidomycosis such tests were negative Most patients were treated with systemic amphotericin B and then an oral azole. The mortality for the whole group was 60%. Patients with diffuse pulmonary disease had the highest mortality (68%), with a median duration of survival of 54 days (P < .05; 95% confidence interval, 147-175 days). The presence of diffuse pulmonary disease and a CD4 lymphocyte count of < 50/microL were independent predictors of death. In our experience, coccidioidomycosis is an important opportunistic infection that causes substantial morbidity and mortality among HIV-infected patients living in an area of endemicity.

AIDS-Related Opportunistic Infections↗
PubMed1995

Mitochondrial enzyme deficiency causing exercise limitation in normal-appearing adults.

Deficiencies of mitochondrial enzymes cause a number of severe neurologic syndromes in pediatric patients. Isolated myopathy secondary to enzymatic deficiency only rarely has been recognized and reported in adults. Three normal-appearing patients with unexplained dyspnea on exertion, tachycardia, and fatigue were studied with progressive incremental and constant load exercise testing with hemodynamic and gas exchange measurements. Subsequently, muscle biopsies were performed and enzymatic profiles determined. Exercise testing suggested altered cellular energy metabolism. Oxygen transport and gas exchange at rest and with exercise were normal. During exercise, ventilation increased excessively for the work performed, but it was appropriate for carbon dioxide production. Cardiac outputs increased significantly (196 to 305%), heart rates reached maximum levels, and lactic acid levels increased (385 to 833%) during exercise at 25 W. Muscle morphology was normal, but mitochondrial enzyme assays demonstrated one or more deficiencies in all three patients. Mitochondrial enzymatic deficiency can be a cause of unexplained exercise symptomatology and limitation in adults. Our experience would suggest the incidence of the disorder may be greater than that previously recognized or expected. Symptoms of exercise limitation associated with dyspnea, tachycardia, or muscle fatigue should alert the clinician to a possible abnormality in cellular energy metabolism.

Adult↗
PubMed1988

Independent developmental regulation of migratory granule neurons and their cerebellar ligand in the mouse.

Interactions between migratory granule neurons and the developing molecular layer of the mouse cerebellum were examined using an in situ binding assay. Single cell suspensions of postnatal granule neurons specifically adhere to unfixed frozen cerebellar tissue sections. We investigated the influence of postnatal age of granule neurons and of tissue on this interaction. Granule neurons from P10 (the time of peak migratory activity) bind preferentially to the molecular layer. Premigratory granule neurons, P5, do not bind age-matched cerebellar tissue. Postmigratory granule neurons, P14 and older, adhere to the molecular and internal granular layers of age-matched and older cerebellar tissue but not to younger tissue. These binding patterns are most simply explained as a single receptor-ligand system in which both elements exhibit independent developmental regulation. Although granule neurons lose the ability to bind with increasing age, the molecular layer ligand retains its capacity for this interaction into adulthood, long after normal migration has ceased.

Aging↗
PubMed1982

Pseudopneumothorax.

An asymptomatic 18-year-old man presented for treatment of alcohol and substance abuse. He related a history of a recent motor vehicle accident with chest trauma and remote history of colonic interposition for esophageal atresia. Radiographic investigation yielded an interesting set of roentgenograms.

Adolescent↗
PubMedDate not supplied

Prolongation of the QT interval related to cisapride-diltiazem interaction.

Cisapride, a cytochrome P450 3A4 (CYP3A4) substrate, is widely prescribed for the treatment of gastrointestinal motility disorders. Prolongation of QT interval, torsades de pointes, and sudden cardiac death have been reported after concomitant administration with erythromycin or azole antifungal agents, but not with other CYP3A4 inhibitors. A possible drug interaction occurred in a 45-year-old woman who was taking cisapride for gastroesophageal reflux disorder and diltiazem, an agent that has inhibitory effect on CYP3A4, for hypertension. The patient was in near syncope and had QT-interval prolongation. After discontinuing cisapride, the QT interval returned to normal and symptoms did not recur. We suggest that caution be taken when cisapride is prescribed with any potent inhibitor of CYP3A4, including diltiazem.

Antihypertensive Agents↗