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Biomedical subjects

J Leatherman

Publications and source records attributed to J Leatherman.

18 recordsLinked to original sources
PubMed1994

Life-threatening asthma.

This article focuses on various issues related to acute, life-threatening episodes of asthma. The areas discussed include epidemiology, clinical assessment, pharmacologic treatment with bronchodilators and anti-inflammatory agents, endotracheal intubation, mechanical ventilation, adjunctive and nonconventional therapy used in the management of the mechanically ventilated asthmatic, and the prognosis of patients who require mechanical ventilation, including both short-term morbidity and long-term outlook.

Adolescent↗
PubMed1992

Infection of fetal scalp electrode monitoring sites.

Complications caused by placement of a fetal scalp electrode include trauma, hemorrhage and infection. Infections are usually localized and self-limited, but they can occasionally lead to serious complications, such as osteomyelitis, sepsis and death. The recommended treatment for a scalp abscess is incision and drainage, followed by appropriate antibiotic therapy. If a serious infection is suspected, the infant should be hospitalized, blood cultures obtained and intravenous antibiotic therapy initiated.

Clinical Protocols↗
PubMed1991

Single night studies in obstructive sleep apnea.

The role of single night studies and the determinants of effective nasal continuous positive airway (CPAP) pressures were determined in 412 consecutive patients between 1984 and 1989. Patients chosen for analysis had an apnea index (AI) of greater than or equal to 20 hr-1 prior to CPAP. The AI was 67 +/- 30 hr-1, the body mass index (BMI) was 36 +/- 9 kg/m2, the age was 51 +/- 13 yr and the lowest oxygen saturation was 72 +/- 14%. Effective CPAP (9 +/- 3 cm H2O) was documented in 320 patients on single night studies and resulted in a 99% reduction in the frequency of obstructive events and improvement in the lowest O2 saturation to 94 +/- 5%. Only 18% of the variability in effective CPAP could be explained by AI and BMI. Single night studies are sufficient to establish effective CPAP in 78% of patients and offer considerable conservation of resources compared to routine multiple night studies. Effective CPAP pressures are variable and must be determined by incremental CPAP trials.

Arousal↗
PubMed1990

How postpartum women explain their lack of obtaining adequate prenatal care.

The quality of life for infants and children is often dependent on the adequacy of the prenatal care pregnant women receive. From July through to December 1985, 15% of pregnant women in one Midwestern county were identified as having inadequate prenatal care. The purposes of the study were to identify and analyse the reasons women in that county gave for not obtaining adequate prenatal care. In addition, chi-square was used to determine the relationship between the reasons given and the three variables, age, time between knowledge of pregnancy and making an appointment for care, and source of payment. A convenience sample (n = 44) was used in a study over a 5-month period at three locations. The Health Belief Model was the conceptual framework for this study. Insufficient money to pay for care was the primary reason given for not obtaining adequate prenatal care (81%). Other reasons included motivational issues (45%) and access or lack of transportation (19%). There was a significant relationship (P = 0.05) with four reasons to the variable of age and with three reasons to both the variables of time and source of payment. The following recommendations were identified as a result of this research: the need for subsidized prenatal care and the need for a community-wide education campaign regarding the need for adequate prenatal care and the consequences of inadequate care. Prenatal care is sometimes not available to all in the United States in spite of the relationship of infant mortality and the quality of life for infants and children to adequate prenatal care.

Attitude to Health↗
PubMed1990

Potassium loading as adjunct treatment of repetitive ventricular arrhythmias.

To evaluate potassium supplementation as adjunct therapy for ventricular arrhythmias, consecutive normokalemic patients undergoing in-hospital antiarrhythmic therapy for ventricular tachycardia were randomly assigned to one of four groups: intravenous potassium chloride (Group I, 44 patients) v intravenous saline (Group II, 48 patients); and oral potassium chloride capsules (Group III 50 patients) v no additional treatment (Group IV, 47 patients). All groups underwent serial serum potassium determinations and 24-hour electrocardiographic monitoring. Analysis revealed no significant differences in ventricular ectopic activity among groups, and there was no significant association between serum potassium level and incidence of ventricular arrhythmias. We conclude that normokalemic patients undergoing antiarrhythmic therapy for ventricular tachycardia benefit little from concomitant short-term potassium supplementation.

Female↗
PubMed1988

Long-term analysis of organelle translocation in isolated axoplasm of Myxicola infundibulum.

Moving intra-axonal organelles demonstrate frequent variations in speed when viewed over several seconds. To evaluate these and other motion variations, a long-term analysis of organelle motion in isolated axoplasm of Myxicola infundibulum was carried out using differential interference contrast optics and analog and digital image enhancement techniques. Motion characteristics of individual organelles were analyzed for periods of up to 58 minutes. Three principle observations on organelle motion were made: 1) Classes of organelles of the same size demonstrated a 5- to 25-fold variation of speed, with the slowest speeds occurring most frequently; 2) organelle speeds over individual translocations (motion without stopping) are inversely proportional to their size, but the speeds calculated for the long-term analysis of organelle motion (total distance travelled/total observation time, including pauses) did not reflect this observation; and 3) organelles displayed variable trip lengths, durations, mean speeds, and pause durations, and the relationships between these variations showed no repetitive patterns. In contrast to reported observations of uniform velocities of organelles moving on isolated microtubule preparations, these observations suggest that a variety of factors must play a role in organelle translocation in Myxicola axoplasm.

Animals↗
PubMed1988

Myocardial infarction and normal coronary arteriography: a 10 year clinical and risk analysis of 74 patients.

Myocardial infarction with normal coronary arteries was identified in 74 patients with a mean age of 43 years (range 19 to 66). A mean follow-up period of 10.5 years after documented myocardial infarction and 8.6 years after cardiac catheterization was obtained. The survival rate was 85% (n = 63). There were no statistical differences in age or clinical risk factor prevalence between survivors and nonsurvivors. Moderate (55%) to severe (27%) left ventricular impairment was more common in nonsurvivors. Nine of 11 deaths were cardiovascular, 6 were sudden and 8 occurred in patients with moderate to severe global left ventricular impairment. Seventy-six percent of survivors were asymptomatic and 86% were fully active at follow-up. Two survivors and three nonsurvivors experienced a second myocardial infarction. The clinical risk factors of the study group (Group I) were compared by age, sex and year of catheterization with risk factors in two matched groups. Group II consisted of 74 patients with coronary occlusive disease and myocardial infarction and Group III consisted of 148 patients with normal arteriograms. Group I differed from Group II in having fewer clinical risk factors (p = 0.01 to less than 0.0001). Cigarette smoking did not differ significantly between Group I (72%) and Group II (69%) but was less common in Group III (45%) (p less than 0.001). Hormone therapy or the peripartum state was more common in women in Group I (34%) than in women in Group III (14%) (p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1987

Computer-assisted versus unassisted analysis of the exercise electrocardiogram in patients without myocardial infarction.

Computer-assisted interpretation of the exercise electrocardiogram has been advocated to improve the accuracy of diagnosing coronary artery disease. Its accuracy was compared with a blinded visual interpretation of exercise-induced ST depression in 271 consecutive subjects without prior myocardial infarction who were referred for coronary angiography. The sensitivity of the visual and computer readings was 0.51 and 0.51, respectively, at a specificity of 0.87. Receiver operating characteristic curves were generated for the visual and computer ST depression in lead V5. Analysis of the areas under these curves showed no significant difference between them, indicating that computer-assisted analysis was not superior to unmodified visual analysis. A similar analysis was applied to two other computer indexes reported to be superior to visual assessments (treadmill exercise score and ST index). These computer indexes were not superior to a conventional visual analysis of leads I, II, V2, V4 and V5 in predicting severe disease (greater than 50% luminal narrowing). These results suggest that computer-assisted interpretation does not improve the accuracy of exercise electrocardiography in diagnosing coronary artery disease in subjects without prior myocardial infarction.

Adult↗
PubMed1986

Bayesian analysis versus discriminant function analysis: their relative utility in the diagnosis of coronary disease.

Both Bayesian analysis assuming independence and discriminant function analysis have been used to estimate probabilities of coronary disease. To compare their relative accuracy, we submitted 303 subjects referred for coronary angiography to stress electrocardiography, thallium scintigraphy, and cine fluoroscopy. Severe angiographic disease was defined as at least one greater than 50% occlusion of a major vessel. Four calculations were done: (1) Bayesian analysis using literature estimates of pretest probabilities, sensitivities, and specificities was applied to the clinical and test data of a randomly selected subgroup (group I, 151 patients) to calculate posttest probabilities. (2) Bayesian analysis using literature estimates of pretest probabilities (but with sensitivities and specificities derived from the remaining 152 subjects [group II]) was applied to group I data to estimate posttest probabilities. (3) A discriminant function with logistic regression coefficients derived from the clinical and test variables of group II was used to calculate posttest probabilities of group I. (4) A discriminant function derived with the use of test results from group II and pretest probabilities from the literature was used to calculate posttest probabilities of group I. Receiver operating characteristic curve analysis showed that all four calculations could equivalently rank the disease probabilities for our patients. A goodness-of-fit analysis suggested the following relationship between the accuracies of the four calculations: (1) less than (2) approximately equal to (4) less than (3). Our results suggest that data-based discriminant functions are more accurate than literature-based Bayesian analysis assuming independence in predicting severe coronary disease based on clinical and noninvasive test results.

Bayes Theorem↗
PubMed1986

Amyotrophic lateral sclerosis: effects of acute intravenous and chronic subcutaneous administration of thyrotropin-releasing hormone in controlled trials.

We performed double-blind crossover trials to assess the effects of thyrotropin-releasing hormone (TRH) on amyotrophic lateral sclerosis patients. For acute intravenous trials, 500 mg TRH or placebo with norepinephrine was given at 1-week intervals (16 patients). CSF TRH concentration increased, and clinical side effects appeared with TRH. For chronic studies, 25 mg TRH and a saline placebo were given subcutaneously every day for 3 months (25 patients). CSF TRH level increased 29-fold after a single TRH injection, and mild transient side effects occurred. Vital signs, respiratory function, semiquantitative and quantitative neurologic function, muscle strength by manual and dynamometer testing, and EMG were studied. With daily TRH, 10 patients noted subjective improvement without objective evidence, and 10 patients complained of worsening of the disease with objective decline after TRH was stopped. Statistical analysis, however, showed no beneficial effects from either acute or chronic TRH trials.

Adult↗
PubMed1986

Spontaneous bacterial peritonitis: clinical and laboratory features with reference to hospital-acquired cases.

A review of a large secondary and tertiary care hospital's experience with spontaneous bacterial peritonitis (SBP) over 7 yr revealed that in most cases this complication emerges after the patient is admitted to the hospital. Compared with a hospitalized control group, SBP patients were more likely to have gastrointestinal bleeding and renal failure and to require invasive procedures or therapies. Thus, hospitalized cirrhotics with ascites who develop SBP are more debilitated before development of SBP. The clinical signs and symptoms of this disorder are diverse; simple tests of ascitic fluid properties (white blood cell count, polymorphonuclear cell count, and lactate dehydrogenase) correlate closely with positive cultures, affording the clinician a chance to make an early presumptive diagnosis. Recognition of nosocomial SBP has important implications for the management of hospitalized cirrhotic patients. Further study is needed to determine if invasive procedures actually cause some cases of SBP or if the apparent association is simply due to identification of a sicker, more debilitated group of patients.

Adult↗
PubMed1985

Videodensitometric ejection fractions from intravenous digital subtraction left ventriculograms: correlation with conventional direct contrast and radionuclide ventriculography.

Forty-three patients who had undergone direct-contrast ventriculography were submitted to intravenous digital subtraction ventriculography and first-pass radionuclide ventriculography to compare the left ventricular ejection fractions obtained by each method. Ejection fractions were calculated by the area-length method from the direct contrast ventriculograms, by both area-length and videodensitometric methods from the digital subtraction ventriculograms, and by count densitometry from the radionuclide ventriculograms. Satisfactory correlations were found between values obtained by the late mask resubtracted videodensitometric method and the radionuclide method (r = 0.85) and by the digital ventriculographic area length method and direct-contrast method (r = 0.88). Videodensitometric methods may be an alternative way to estimate left ventricular ejection fractions accurately without reliance on geometric assumptions about the shape of the left ventricular cavity.

Analog-Digital Conversion↗
PubMed1985

Digital subtraction fluoroscopy: a new method of detecting coronary calcifications with improved sensitivity for the prediction of coronary disease.

The association between calcification of the coronary arteries and coronary artery narrowing is well established. However, fluoroscopic visualization of coronary calcifications has been insufficiently sensitive to be useful as a screening test. Since digitization of radiographic images permits the subtraction of noncardiac structures from moving cardiac structures, such subtraction might increase the sensitivity of coronary fluoroscopy. To determine whether coronary calcifications were better visualized with digital subtraction fluoroscopy than with conventional fluoroscopy, we taped diseased human coronary arteries to a pulsating water balloon inside the thorax of a dog cadaver and studied this model with both fluoroscopic techniques. Calcific atherosclerotic plaques were more easily identified with digital subtraction fluoroscopy than with conventional fluoroscopy. We tested the method clinically by submitting 191 subjects without history or electrocardiographic evidence of previous myocardial infarction who were referred for coronary arteriography to both fluoroscopic studies. For at least one, at least two, and three calcified coronary arteries, digital fluoroscopy was more sensitive (92%, 66%, and 40%) than conventional fluoroscopy (63%, 21%, and 2%) (all p less than .001) for the prediction of significant coronary obstructions (greater than 50%). Although digital fluoroscopy was less specific than conventional fluoroscopy (digital: 65%, 89%, and 97%; conventional: 81%, 98%, and 100%) (all but last, p less than .01), receiver operating curve analysis revealed a significantly larger area under the curve, indicating higher accuracy for the digital technique (p = .03). Digital subtraction fluoroscopy was more accurate in younger than in older patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1984

Bayesian probability analysis: a prospective demonstration of its clinical utility in diagnosing coronary disease.

One hundred fifty-four patients referred for coronary arteriography were prospectively studied with stress electrocardiography, stress thallium scintigraphy, cine fluoroscopy (for coronary calcifications), and coronary angiography. Pretest probabilities of coronary disease were determined based on age, sex, and type of chest pain. These and pooled literature values for the conditional probabilities of test results based on disease state were used in Bayes' theorem to calculate posttest probabilities of disease. The results of the three noninvasive tests were compared for statistical independence, a necessary condition for their simultaneous use in Bayes' theorem. The test results were found to demonstrate pairwise independence in patients with and those without disease. Some dependencies that were observed between the test results and the clinical variables of age and sex were not sufficient to invalidate application of the theorem. Sixty-eight of the study patients had at least one major coronary artery obstruction of greater than 50%. When these patients were divided into low-, intermediate-, and high-probability subgroups according to their pretest probabilities, noninvasive test results analyzed by Bayesian probability analysis appropriately advanced 17 of them by at least one probability subgroup while only seven were moved backward. Of the 76 patients without disease, 34 were appropriately moved into a lower probability subgroup while 10 were incorrectly moved up. We conclude that posttest probabilities calculated from Bayes' theorem more accurately classified patients with and without disease than did pretest probabilities, thus demonstrating the utility of the theorem in this application.

Angiography↗
PubMed1976

Experimental acid-aspiration pneumonia in the rabbit. A pathologic and morphometric study.

Four anesthetized rabbits given intratracheal injections of hydrochloric acid, pH 1.5, 2 ml/kg, were killed 4 h later. A fifth rabbit was an untreated control. Each lung had a few red-brown patches of compression atelectasis. Microscopically, treated lungs had a severe exudative necrotizing bronchitis, bronchiolitis, and alveolitis. There was also intra-alveolar hemorrhage and edema. Electron microscopy showed folds, projections and focal swellings of type I cells lining affected alveoli. A morphometric study showed 69% of parenchyma to be normal, 26% edematous and 5% hemorrhagic. In the airways 58% of the epithelium was damaged.

Animals↗