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Biomedical subjects

S Norris

Publications and source records attributed to S Norris.

At least 55 records · Page 3Linked to original sources
PubMed1995

Differential perceptions, behaviors, and motivations among African Americans, Latinos, and whites suspected of heart attacks in two hospital populations.

To evaluate the hypothesis that socioeconomic status would exert greater influence on patients' care-seeking behavior than racial/ethnic group status, we undertook a sequential study of African-American, Latino, and white patients hospitalized for acute chest pain from August 1988 through July 1990 at two sites. The study took place in an urban public medical center and an urban private health maintenance organization medical center, which provide care to mixed racial/ethnic groups of lower and middle socioeconomic status, respectively, in Los Angeles. Three concurrent case series of African-American, Latino, and white patients hospitalized for acute chest pain were recruited. The racial/ethnic distribution of the total group was African Americans, 448; Latinos, 487; and whites, 499. The main outcome measure was the length of time patients spent in deciding to seek emergency medical care for acute chest pain and the associated perceptions, behaviors, and motivations involved in deciding to seek care. For the total group, public hospital site and lack of health insurance were the strongest significant predictors of a longer decision phase, whereas differential symptom perceptions, consultation with medical professionals, and use of paramedic transport were significant predictors of shorter duration. Multiple regression results were similar in separate analyses demonstrated significant differences in patients' perceptions of symptom intensity and incapacitation within racial/ethnic groups related to socioeconomic status, as well as in specific behavior and motivation in seeking care. The study concluded that socioeconomic status as determined by hospital site exerted a stronger influence on patients' care-seeking behavior for acute chest pain than racial/ethnic status. Specific care-seeking behaviors of minority and lower-socioeconomic-status patients in the use of medications and paramedics in the face of acute symptoms should be targeted in future educational programs.

Adult↗
PubMed1994

Prevention of relapse of histoplasmosis with fluconazole in patients with the acquired immunodeficiency syndrome.

OBJECTIVE: To assess the effectiveness of fluconazole for suppression of relapse of histoplasmosis in patients with acquired immunodeficiency syndrome (AIDS). DESIGN: Retrospective, nonrandomized, open trial. SETTING: Multicenter at two university referral centers and in five private practices. PATIENTS: Seventy-six patients with AIDS and disseminated histoplasmosis who completed induction treatment with amphotericin B, itraconazole, or fluconazole and maintained on treatment with fluconazole to prevent relapse. INTERVENTIONS: Fluconazole was given at dosages of 100 to 400 mg per day. Patients were followed by their primary physicians, who completed questionnaires collecting information about treatment and relapse status. Blood and urine specimens were submitted periodically for Histoplasma capsulatum var. capsulatum antigen determination. MEASUREMENTS AND MAIN RESULTS: Nine of the 76 patients relapsed during fluconazole therapy and another was removed from the study because of allergic rash. Survival after initiation of therapy for histoplasmosis was 94 weeks, ranging from 74 weeks for those who received less than 1 g of amphotericin B for induction and none for maintenance therapy to 156 weeks for those who received greater than 1 g for induction and additional amphotericin B for maintenance therapy before beginning fluconazole (P < 0.02). Antigen levels fell at rates of 0.05 units/week in urine and 0.02 units/week in serum in patients who were successfully maintained in remission and increased by > or = 2 units/week in 4 of 6 patients who relapsed. CONCLUSIONS: Fluconazole > or = 200 mg daily is a reasonable choice for chronic suppressive therapy of histoplasmosis in patients who cannot take itraconazole because of drug interactions, malabsorption, or side effects.

AIDS-Related Opportunistic Infections↗
PubMed1994

Maxillofacial fractures: a study of recurrent victims.

A study of 760 patients treated for maxillofacial fractures over a 2 year period revealed 3 per cent of them to have had one or more previous fractures in the maxillofacial region. This group of patients are nearly all victims of assault but are indistinguishable from a control group of patients with maxillofacial injuries on the grounds of age, sex, anatomical type of injury or socioeconomic status. They are however more likely to have been drinking alcohol at the time of their injury than the control group. We advocate targeting of this sub-group of patients with maxillofacial fractures for appropriate counselling.

Accidents, Traffic↗
PubMed1994

Prediction of stroke volume from oxygen pulse measurements in untrained and trained men.

This study examined the relationship of oxygen pulse (O2 pulse) to stroke volume (SV) and arterio-venous oxygen difference [(a-v)O2 diff] during submaximal cycle exercise in untrained (UG) and trained (TG) males. Fourteen volunteers in each group completed an incremental VO2 max test and a submaximal test at 60% VO2 max to determine cardiac output (Q) via CO2 rebreathing. VO2, Q, and heart rate (HR) were used to calculate SV and (a-v)O2 diff. There were no significant differences (p > .05) between the two groups for O2 pulse, SV, and (a-v)O2 diff during submaximal exercise. Stroke volume index (SVI) was significantly higher (p < .05) in the TG. O2 pulse was significantly related to SV and SVI (p < .05) but not to (a-v)O2 diff in both groups. Regression equations for predicting SV from O2 pulse for UG and TG were Y = 6.81X + 26.7, SE = 21.4, r = 0.84, and Y = 10.33X - 32.3, SE = 14.2, r = 0.71, respectively. These results suggest that O2 pulse can be used to predict SV during submaximal cycle exercise in untrained and trained men.

Adult↗
PubMed1994

Research priorities for all phases of postanesthesia nursing: a survey by ASPAN.

This ASPAN survey was conducted by Research Committee members regarding the future of research for postanesthesia nursing and asked this question: What do postanesthesia nurses view as priorities for postanesthesia nursing research in various phases of practice? The design for the study was the Delphi technique, which uses a multiple, sequential survey to reach consensus among a group of experts. Four rounds of questionnaires were used to survey volunteer participants (N = 54). The group of experts remained stable (N = 41) for rounds 2 through 4. Findings from the survey indicated several areas of priorities for postanesthesia nursing. Of the top 10 ranked statements, 4 related to discharge criteria. Another high-priority area identified was pain management, with 5 statements pertaining to this subject being ranked in the top 10. Based on this small sample of postanesthesia nurses, this study provides a beginning step for prioritizing areas of research necessary to expand the body of knowledge for postanesthesia nursing.

Adult↗
PubMed1993

A phase I trial of immunosuppression with anti-ICAM-1 (CD54) mAb in renal allograft recipients.

Several adhesion molecules contribute to the interaction between T cells and antigen presenting cells or target cells. Leukocyte function-associated molecule-1 (LFA-1[CD11a/CD18]) and intercellular adhesion molecule-1 (ICAM-1 [CD54]) are one such critical adhesive receptor-counter-receptor combination. The importance of ICAM-1 dependent adhesion in the rejection response was initially demonstrated in cynomolgus renal allograft recipients treated with the anti-ICAM-1 murine monoclonal antibody BIRR1. BIRR1 also appeared to limit ischemic damage in these animals. A Phase I clinical trial has subsequently been completed in 18 patients who received cadaver donor renal allografts at high risk for delayed graft function (prolonged preservation time, highly-sensitized recipient). An adequate BIRR1 serum level was associated with significantly less delayed graft function (P < .01) and rejection (P < .01). In 1-hr biopsies, mouse IgG was detected along the endothelium of the vessels and glomeruli in the graft. There were no instances of primary non-function (PNF), and current allograft survival (followup: 16-30 months) in these "high-risk" mAb-treated patients is 78%. There were 3 instances of PNF and a graft survival rate of 56% in the recipients of the contralateral kidney allografts treated with conventional immunosuppression. No significant "first-dose" effect was associated with BIRR1 administration. These results establish a dosing schedule and the clinical safety of BIRR1. They also suggest that inhibition of leukocyte adhesion by mAb therapy may be useful in controlling allograft rejection and possibly in limiting reperfusion injury. Thus, these observations support the clinical importance of accessory molecules in T cell function. We hypothesize that anti-CD54 mAb acts by blocking leukocyte adhesion to the endothelium, thereby interfering with sensitization or target cell interaction.

Adolescent↗
PubMed1993

Chest pain admissions: characteristics of black, Latino, and white patients in low- and mid-socioeconomic strata.

To assess the potential impact of socioeconomic status (SES) factors on health-care seeking behavior for suspected acute coronary artery disease symptoms, equal numbers of black, Latino, and white patients seeking care for chest pain at two large hospital emergency rooms were studied. Differences between low and middle SES groups with respect to pre-attack health, health history, ethnicity, gender, and modes of transportation to the hospital were explored. Highly significant self-reported differences between low SES and middle SES patients were found as follows: low SES subjects were more likely to describe themselves as being in fair to poor general health (68% versus 18%), had more frequent chest pain, reported other types of heart disease, were more often current smokers, more likely to be black or Latino, and to be younger. Members of the low SES group also were less [corrected] likely to have known cholesterol levels, to have used estrogen, to have had a prior ECG or cardiac surgery, to be nonsmokers, to have had a stress test, and to have typical angina. Middle SES subjects more often described typical angina, prior use of estrogen (females), congenital, rheumatic, or family history of heart disease, prior knowledge of high cholesterol, were more likely to be of the male gender, and to be older than the low SES cohort. The data reveal that low SES subjects, with markedly less health-care resources compared with middle SES subjects, have a worse general health and cardiac risk profile despite the fact that they were significantly younger (mean age 53.4 versus 60.7, P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Black or African American↗
PubMed1993

Effects of skin blood flow and temperature on bioelectric impedance after exercise.

To examine the effects of increased skin blood flow (BFsk) and skin temperature (Tsk) on bioelectric impedance (BIA), 30 young males participated as subjects. All subjects underwent the following measurements: 1) BFsk and Tsk for the chest, biceps, thigh, and calf; 2) body composition using the BIA prediction equations and underwater weighting (UW); and 3) triceps skinfold (SFtri) thickness. After the baseline studies (M1) the subjects exercised for 30 min at approximately 83% of maximal heart rate. The above measurements were repeated immediately after exercise (M2), and at 1-h recovery from exercise (M3). Repeated measures ANOVA showed that mean Tsk and BFsk, and for the four measured sites were significantly increased from M1 to M2 (P < 0.05) and decreased from M2 to M3 (P < 0.05). These changes did not affect BIA measurement for resistance (R) and reactance between M1 and M2 (P > 0.05), and between M2 and M3 (P > 0.05). With regression analysis the following independent variables were identified as strong contributing factors for predicting fat-free mass (FFM): 1) SFtri and total body water for M1 and M3; and 2) WT, SFtri, and Tsk of the chest for M2. Two FFM equations have little multicolinearity (M1 and M2), e.g., they have low root mean square errors (< or = 2.6 kg), very high values for R2 (> or = 0.94), and relatively low values for coefficient of variations (< or = 5.65%). Differences (P < 0.05) were observed between the UW method and the Lukasi equation for estimating FFM for M1 and M3, but not for M2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Pulmonary aspergillosis in the acquired immunodeficiency syndrome.

BACKGROUND AND METHODS: Symptomatic pulmonary aspergillosis has rarely been reported in patients with the acquired immunodeficiency syndrome (AIDS). We describe the predisposing factors, the clinical and radiologic features, and the therapeutic outcomes in 13 patients with pulmonary aspergillosis, all of whom had human immunodeficiency virus (HIV) infection and 12 of whom had AIDS. RESULTS: Pulmonary aspergillosis was detected a median of 25 months after the diagnosis of AIDS, usually following corticosteroid use, neutropenia, pneumonia due to other pathogens, marijuana smoking, or the use of broad-spectrum antibiotics. Two major patterns of disease were observed: invasive aspergillosis (in 10 patients) and obstructing bronchial aspergillosis (in 3). Cough and fever, the most common symptoms, tended to be insidious in onset in patients with invasive disease (median duration, 1.3 months before diagnosis). Breathlessness, cough, and chest pain predominated in the three patients with obstructing bronchial aspergillosis, who coughed up fungal casts. Radiologic patterns included upper-lobe cavitary disease (sometimes mistaken for tuberculosis), nodules, pleural-based lesions, and diffuse infiltrates, usually of the lower lobe. Transbronchial biopsies were usually negative, but positive cultures were obtained from bronchoalveolar-lavage fluid or percutaneous aspirates. Dissemination to other organs occurred in at least two patients, and direct invasion of extrapulmonary sites was seen in two others. The results of treatment with amphotericin B, itraconazole, or both were variable. Ten of the patients died a median of 3 months after the diagnosis (range, 0 to 12 months). CONCLUSIONS: Pulmonary aspergillosis is a possible late complication of AIDS; if diagnosed early, it may be treated successfully.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Ceftazidime in the elderly: appropriateness of twice-daily dosing.

The disposition of drugs in the elderly is particularly relevant with antiinfectives, because this population has an increased risk of infections. Renal function deteriorates with age, yet dosage guidelines for antibiotics that allow for this reduction remain to be established. Ceftazidime, a cephalosporin with enhanced antipseudomonal activity that is eliminated primarily by glomerular filtration, has been evaluated in the elderly. Herein, we review ceftazidime's pharmacokinetic profile and dosing considerations in this population. Several aspects of renal function deteriorate with the normal aging process, including a decreased glomerular filtration rate (GFR). Using serum creatinine concentrations as an estimate of the GFR in the elderly is unreliable; a more reliable way of estimating GFR is the use of inulin or 51Cr-editic acid clearance or calculation from formulas or nomograms based on age, weight, sex, and serum creatinine. From pharmacokinetic studies it was found that the elderly individual without renal disease generally has an increased elimination half-life and decreased clearance of ceftazidime compared with a young person. A positive correlation (r = 0.7-0.95) was shown between ceftazidime clearance and GFR, suggesting that estimates of GFR may be used to determine the ceftazidime dose. In several studies, the trough (after 12 hours) ceftazidime serum concentration exceeded by several fold its minimum inhibitory concentration required to inhibit 90% of organisms for most commonly encountered organisms; efficacy and safety were also confirmed with an every-12-hour regimen. A twice-daily dosage regimen for ceftazidime in elderly patients with normal renal function should be considered based on age-related decreases in renal function and drug elimination.

Adult↗
PubMed1991

Sickle cell anemia: does myocardial ischemia occur during crisis?

The possibility that myocardial ischemia may be associated with chest pain during painful crises was evaluated prospectively in 20 patients (11 women and nine men) with sickle cell disease (19 SS, 1 S beta + thalassemia). Sixteen of 20 (80%) had abnormal ECGs, 7 (35%) had transient ST-T wave changes, and 3 (15%) had persistent ST-T wave changes, both consistent with ischemia; 6 (30%) had nonspecific ST-T changes, and 4 (20%) had normal tracings. Serum enzymes (CK, SGOT, LDH) were abnormal in 16 of 19 (84%); 1 had CK-MB detected, (5%) and 1 had LDH1 to LDH2 reversal. All 10 Tc-99m pyrophosphate scans performed were negative; 4 of 6 (66%) thallium-201 scans had focal defects, and 5 of 8 (63%) radionuclide angiograms (MUGAs) had focal wall motion abnormalities. Three of 8 (38%) MUGAs showed cardiac dilation, diffuse hypokinesis, and reduced ejection fractions. Thus, myocardial damage may be a potentially serious complication of patients with sickle cell anemia who present with chest pain during painful crises. Studies are indicated to define the significance and pathophysiology of these observations.

Adult↗
PubMed1990

Pharmacokinetic and pharmacodynamic studies in man with an antianginal agent 'Visacor'.

This randomized, double-blind, crossover study in 10 healthy male volunteers compared four single oral doses of ICI 141,292 ('Visacor'), i.e. 50, 100, 200, and 300 mg, with placebo. Venous blood samples were collected pre-dose and at various times after dosing and the concentrations of ICI 141,292 in the plasma were determined by radioimmunoassay. A standardized 4-min bicycle exercise test was also performed and before this the resting haemodynamic parameters were assessed. Peak plasma concentrations of ICI 141,292 and the area under the plasma concentration-time curve increased disproportionately with dose such that after scaling to a dose of 200 mg there remained a significant linear trend with dose. The time to peak plasma concentration displayed an increasing trend with dose and, once again, the linear component of this trend was statistically significant. The mean heart rates during exercise were all significantly reduced compared to placebo for 24 h by each of the doses (range 7.8 to 17.4 beats min-1 at 24 h, p less than 0.01). The increase in heart rate during exercise was inversely related to the logarithm of the ICI 141,292 plasma concentration with higher plasma concentrations being associated with lower heart rate increases. The mean supine resting heart rates were slightly but significantly reduced at 2 and 6 h after dosing by each treatment and by the 300 mg dose at 24 h. Each of the doses of ICI 141,292 was well tolerated.

Adrenergic beta-Antagonists↗
PubMed1989

Postischemic recovery rate of cerebral ATP, phosphocreatine, pH, and evoked potentials.

We tested the hypotheses that after complete cerebral ischemia, first, rate of recovery of ATP, phosphocreatine (PCr), and intracellular pH (pHi) varies with ischemic duration and second, rate of metabolic recovery is a more sensitive predictor of consequent electrophysiological deficit than steady-state metabolic recovery. With the use of transient intracranial hypertension in anesthetized dogs, ischemic duration was set for either 3, 12, or 30 min, which depressed somatosensory-evoked potential (SEP) recovery amplitude by 30, 59, and 88%, respectively. In contrast, ATP, PCr, and pHi, measured by 31P magnetic resonance spectroscopy, fully recovered. When ischemic duration was increased from 3 to 12 min, mean recovery time of ATP (6 min) remained rapid but that of pHi (12-28 min) was prolonged. After 30 min of ischemia, pHi recovery was not slowed further (25 min) but that of ATP was now markedly prolonged (36 min). PCr recovery time increased progressively with ischemic duration (5, 11, and 21 min, respectively) and correlated best with SEP recovery (r = 0.74). We conclude that the brain's ability to rapidly normalize pH is a sensitive predictor of electrophysiological recovery after short ischemia but that ATP regeneration becomes important with prolonged ischemia. PCr recovery rate was the best overall predictor, probably because it depends on both pHi and the ratio of ATP to ADP by the creatine kinase reaction.

Adenosine Triphosphate↗
PubMed1988

Comparison of computer and non-computer-assisted technologies in noninvasive cardiac imaging.

We compared gated magnetic resonance imaging (MRI) and dynamic computed tomography (DCT) with two-dimensional cardiac ultrasound (ECHO) to assess differences in diagnostic information. Magnetic resonance imaging was performed in 41 patients; ECHO in 36, and DCT in 28 patients with various pathologic conditions. We measured the left and right ventricular (LV, RV) long and short axes (LA, SA), LV free wall and septal thickness (WT, ST) at end systole (ES) and end diastole (ED) on the apical four-chamber view (ECHO) or appropriate transaxial slice (MRI, DCT) on a subset of 14 patients. Paired-sample analysis of these three techniques, in this preliminary data, yields statistically different results as follows: LV SA: MRI versus ECHO at ED and ES (P less than 0.001 and 0.005); WT: MR versus ECHO at ES (P less than 0.002); CT versus ECHO at ED and ES (P less than 0.05 and 0.01); ST: MRI versus ECHO at ED and ES (P less than 0.001), and CT versus ECHO at ES (P less than 0.05). Thus, CT and MRI yield similar quantitative data, but both differ in varying degree from ECHO measurements. Differential accuracies and utilities of these techniques warrant further careful investigation.

Echocardiography↗