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Biomedical subjects

S M Davis

Publications and source records attributed to S M Davis.

At least 91 records · Page 5Linked to original sources
PubMed1997

Risks of infection or reactivation of tuberculosis associated with chronic corticosteroid therapy.

Although corticosteroids are known to be immunosuppressive, there have been no studies to show that use of corticosteroids increases the risk of developing new tuberculosis or reactivating old tuberculosis. In fact, corticosteroids are recommended for the treatment of several forms of tuberculosis, such as pleural tuberculosis, genitourinary tuberculosis, and tuberculous meningitis. Clinicians should still be alert for tuberculosis appearing in immunocompromised patients as a disseminated infection or for tuberculosis that is atypical in appearance.

Adrenal Cortex Hormones↗
PubMed1997

Volumetric analysis of cerebral hypoperfusion on SPECT: validation and reliability.

UNLABELLED: A method of volumetric analysis of hypoperfusion on 99mTc-labeled hexamethylpropylene amine oxime SPECT has been developed. This analysis integrates both the size and severity of perfusion reduction, yielding an equivalent volume of cortical tissue having zero blood flow, or the effective hypoperfusion volume. This study aimed to validate the methodology in vitro using the Hoffman brain phantom and two different camera systems, to examine the relationship between spatial resolution and accuracy of volume measurement and to assess the interobserver variability in SPECT studies of stroke patients. METHODS: Simulated cortical lesions of three different sizes were sequentially incorporated into the Hoffman brain phantom and imaged using both single- and triple-head camera systems. For each system and for each lesion size, successive acquisitions were performed using three progressively larger radii of camera rotation. The hypoperfusion volume for each study was measured three times by a blinded observer, and the percentage difference from the true lesion volume was then calculated. SPECT studies of 32 stroke patients were independently analyzed by two blinded observers. RESULTS: At the smallest radii of rotation, mean (s.d.) percentage difference between observed and true volumes was 0.90% (4.80%) for the triple-head and 4.50% (11.58%) for the single-head system. The degree of overestimation was similar for both systems. Percentage overestimation was strongly associated with radius of rotation (B = 0.71 +/- 0.32, p = 0.04 for the triple-head system; B = 1.26 +/- 0.55, p = 0.03 for the single-head system) but not with lesion size. The mean difference between hypoperfusion volumes of stroke patients obtained by two observers was 0.045 (3.240) cm3, which was not significant. CONCLUSION: This study has shown that this technique of volumetric analysis of regional hypoperfusion on SPECT is both highly accurate and reproducible between two different camera systems. The degree of overestimation chiefly relates to diminishing spatial resolution. Despite some element of subjectivity, the interobserver variability is negligible.

Animals↗
PubMed1996

Food preferences, practices, and cancer-related food and nutrition knowledge of southwestern American Indian youth.

BACKGROUND: Pathways to Health is a cancer prevention and health promotion curriculum for fifth- and seventh-grade Navajo and Pueblo students living in New Mexico. METHODS: A diet and nutrition questionnaire was administered to 1007 fifth- and seventh-grade students before beginning the Pathways to Health intervention. Sections of the questionnaire included listing favorite foods, frequency of intake of selected foods (e.g., "How often do you eat vegetables?"), targeted food practices (e.g., "When you eat chicken, do you eat the skin?"), and applied dietary fat and fiber knowledge questions. Descriptive analyses were generated by grade, gender, and tribe. RESULTS: Students' favorite foods were pizza, hamburgers, and tacos. Only 35.7% of students reported consuming the U.S. Dietary Guidelines recommendation of two or more daily servings of fruit, with only 19.3% reporting more than once-a-day intake of vegetables. The mean score (percent correct responses) to questions identifying common food sources of dietary fat and fiber, and other cancer-related nutrition knowledge questions, was 45.2% and 57.9% for fifth- and seventh-grade students, respectively. CONCLUSIONS: These and related data support the need for nutrition education interventions in this population that target essential cancer prevention skills and motivational information required to make positive dietary choices.

Adolescent↗
PubMed1996

Four Corners Research Consortium for Native Americans and cancer research.

Cancer morbidity and mortality in Native Americans in the Southwestern four-corners region of the United States (Arizona, Colorado, New Mexico, and Utah) is of critical concern to public health workers, health care providers, cancer researchers, and Native American communities of the region. As a follow-up to the national conference in Seattle, Washington, representatives from the Arizona, Colorado, New Mexico, and Utah Cancer Centers, the AMC Cancer Research Center, and the Indian Health Service participated in a regional conference on September 26, 1995. The primary reason for the "Four Corners Consortium" meeting was to assess cancer research activities in each state and to determine how Native American cancer research could be organized in the four-state region. One interest of the group was to determine strategies to explore why some cancers are more or less prevalent among Southwest Native American populations and to evaluate how the group might jointly establish research that would address the cancer needs of Southwestern tribes.

Arizona↗
PubMed1996

Streptokinase for acute ischemic stroke with relationship to time of administration: Australian Streptokinase (ASK) Trial Study Group.

OBJECTIVES: To determine whether the administration of 1.5 million units of streptokinase intravenously within 4 hours of the onset of acute ischemic stroke would reduce morbidity and mortality at 3 months and whether outcomes may be better for those receiving therapy within 3 hours of stroke onset compared with those receiving it after 3 hours. DESIGN: Randomized, double-blind, placebo-controlled trial with 3-month follow-up. PARTICIPANTS: A total of 340 patients, aged 18 to 85 years, with moderate to severe strokes were randomized from 40 centers throughout Australia from June 1992 to November 1994. INTERVENTION: Administration of 1.5 million units of streptokinase or placebo intravenously in 100 mL of normal saline over 1 hour. MAIN OUTCOME MEASURE: Combined death and disability score (Barthel index <60) 3 months after the stroke. RESULTS: Using an intention-to-treat analysis with a combined death and disability score at 3 months after stroke as the primary end point, we found a nonsignificant overall trend toward unfavorable outcomes for streptokinase vs placebo (relative risk [RR] of unfavorable outcome, 1.08; 95% confidence interval [CI], 0.74-1.58) and an excess of hematomas (13.2%[12.6% symptomatic] in the treated group, 3% [2.4% symptomatic] for placebo [P<.01]). However, poor outcomes were confined to patients receiving therapy more than 3 hours after stroke onset (RR of unfavorable outcome, 1.22; 95% CI, 0.80-1.86). In contrast, among the 70 patients who were entered into the trial within 3 hours of stroke onset, there was a trend toward improved outcomes for those who received streptokinase (RR of unfavorable outcome, 0.66; 95% CI, 0.28-1.58), and this outcome pattern was significantly better than for those receiving therapy after 3 hours (P=.04). Streptokinase administration resulted in excess deaths in the group treated after 3 hours (RR, 1.98; 95% CI, 1.18-3.35), but not among those treated within 3 hours (RR, 1.11; 95% CI, 0.38-3.21). CONCLUSION: The administration of streptokinase within 4 hours of acute ischemic stroke increased morbidity and mortality at 3 months. While treatment within 3 hours of stroke was safer and associated with significantly better outcomes than later treatment, it showed no significant benefit over placebo. The timing of thrombolytic therapy for acute stroke is critical.

Acute Disease↗
PubMed1996

Streptokinase increases luxury perfusion after stroke.

BACKGROUND AND PURPOSE: Recent acute stroke trials have reported that intravenous streptokinase is associated with an increased risk of adverse outcomes. We aimed to study the effect of streptokinase on the nature of reperfusion and the relation between reperfusion and clinical outcome. METHODS: We studied 24 patients in the Australian Streptokinase Trial with acute middle cerebral cortical infarction using 99mTc-hexamethylpropyleneamine oxime single-photon emission CT. Eleven of the 24 patients were scanned before therapy and again 24 hours later. The remaining 13 were scanned once either before therapy (1 patient) or after therapy (12 patients). All patients had outcome scans after 3 months. Infarct hypoperfusion was measured with a validated volumetric technique. Neurological impairment and functional outcome were assessed with the Canadian Neurological Scale and the Barthel Index, respectively. RESULTS: Fifteen patients received streptokinase and 9 received placebo. There was no difference in early reperfusion between streptokinase and placebo. However, streptokinase was associated with a greater amount of nonnutritional reperfusion than was placebo (P = .04). This luxury perfusion was associated with poor functional outcome (P = .02). CONCLUSIONS: This study suggests that streptokinase augments luxury perfusion after stroke. Luxury perfusion is associated with a worse outcome, which might be due in part to reperfusion injury.

Adult↗
PubMed1996

Microemboli during carotid angiography. Association with stroke risk factors or subsequent magnetic resonance imaging changes?

BACKGROUND AND PURPOSE: Carotid angiography is associated with a 1% risk of major stroke. Recently, transcranial Doppler ultrasonography (TCD) has shown cerebral microemboli during carotid angiography. To determine their significance, we correlated the number of microemboli during angiography with clinical characteristics, angiography findings, and preangiography and postangiography cerebral magnetic resonance imaging (MRI). METHODS: One middle cerebral artery was monitored with TCD in 24 patients during angiography for carotid territory ischemia. The number of microemboli was correlated with angiographic and clinical characteristics. T2-weighted cerebral MRI was performed before and < or = 48 hours after angiography, and the number of new ischemic lesions was determined in a blinded review. RESULTS: Microemboli were seen in all patients, with an average of 51 per procedure (range, 12 to 154). The majority of microemboli had signal characteristics typical of air. Sixteen of the 24 patients had both preangiography and postangiography MRI. One of 24 patients had an angiographic stroke, with a single new thalamic lesion on MRI. No other patient had a new lesion. The microembolus count correlated with the angiographic contrast volume (P < .001) but not with any other radiological or clinical characteristic. CONCLUSIONS: This study confirmed the presence of numerous cerebral microemboli during carotid angiography. The microembolic signal characteristics and the correlation with contrast volume indicate that introduced air is the cause. These microemboli are usually clinically silent and do not lead to new changes on cerebral MRI.

Adult↗
PubMed1996

Faculty commitment: retaining minority nursing students in majority institutions.

Minority students are at risk in majority institutions. Students face personal, academic, and institutional barriers to their success. Low retention and graduation rates at majority institutions, and particularly in nursing programs, are cause for alarm and compel nursing faculty to take action in order to reverse the trend of under-representation of minorities in the ranks of the profession. Based on the literature and personal experiences, the authors maintain that commitment of both minority and majority faculty is the primary factor in promoting minority student success. Such commitment can lead to increased involvement of faculty in the success of minority students and to the establishment of organized programs and services that facilitate minority student success. Case illustrations are included.

Attitude↗
PubMed1995

Prediction of functional outcome and tissue loss in acute cortical infarction.

OBJECTIVE: To compare the acute Allen's Prognostic Score, Canadian Neurological Score, and subacute Barthel Index as predictors of outcome functional status and infarct size at 3 months in patients with acute cortical infarction. DESIGN: A prospective study of acute stroke predictors and outcome measurements in a cohort of sequential hospitalized patients. PATIENTS: Fifty-one patients with acute cortical infarction and without previous disability assessed 24 hours after onset with Allen's Prognostic Score and the Canadian Neurological Score and at 7 days with the Barthel Index. MAIN OUTCOME MEASURES: Mortality, Barthel Index, and volumetric measurement of infarct size on computed tomography 3 months after stroke. RESULTS: There were seven deaths. The outcome Barthel Index was measured in all 44 survivors, of whom 29 had computed tomography at the time outcome was determined. In a multivariate analysis, functional outcome was best predicted by Allen's Prognostic Score, a score of less than -15 having a sensitivity of 82% and specificity of 97% in predicting a poor outcome (Barthel Index, < or = 12 or death). Volumetric tissue loss was predicted only by Allen's Prognostic Score (r = .62, P < .001). CONCLUSIONS: Allen's Prognostic Score is a robust predictor of both functional outcome and tissue loss in acute cortical infarction and has a potentially important role in the analysis of the results of acute stroke intervention trials.

Activities of Daily Living↗
PubMed1995

Tobacco use: baseline results from pathways to health, a school-based project for southwestern American Indian youth.

BACKGROUND: This paper describes a school-based cancer prevention project for fifth- and seventh-grade Navajo and Pueblo Indian children living in the Southwest. Baseline data are presented from 714 students who completed questionnaires on smoking and smokeless tobacco. METHODS: Questionnaires were administered in the fifth- and seventh-grade classrooms prior to students receiving the Pathways to Health cancer prevention curriculum. RESULTS: In our sample there were increases from fifth to seventh grade in self-reported current cigarette use and intention to use. Also, boys were more likely to use and intend to use cigarettes than girls. The use of smokeless tobacco also increased with increasing grade level, though this trend was less pronounced for girls. A significant gender difference was found in the use of smokeless tobacco with boys reporting higher use. However, reported use by girls was higher than is typically noted for non-Hispanic white girls. CONCLUSIONS: There is evidence of experimentation and regular use of tobacco products by both Navajo and Pueblo boys and girls. Even more students indicate intention to use tobacco products in the future. These data confirm the need for primary prevention programs designed for this population of American Indians.

Adolescent↗
PubMed1995

Thrombolytic therapy for basilar artery thrombosis in the puerperium.

A case is presented of a woman in whom basilar artery thrombosis developed 14 days post partum. She was successfully treated with intraarterial urokinase. This case demonstrates that complete neurologic recovery can be achieved after recanalization of the basilar artery with thrombolytic therapy.

Angiography↗
PubMed1995

An investigation into nurses' understanding of health education and health promotion within a neuro-rehabilitation setting.

This qualitative study was undertaken at two neuro-rehabilitation centres in England, with the aim of exploring the nurses' understanding of health education and health promotion and their role within it, and their perception of illness and wellness related to disability. The principle of methodical triangulation was employed using questionnaires, group interviews and content analysis of client care plans. Although the nurses had difficulty distinguishing between health promotion and health education, differences did emerge which were supported by the literature. The nurses generally identified their role as being one of health promotion. However, they tended to equate wellness with physical independence. As a result of the study a health promotion model based on the principles of self-empowerment is suggested, which could be used as a framework for rehabilitation nurses and other professionals to enable them to focus on health and wellness rather than illness and disability.

Adult↗