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Biomedical subjects

R P Hirsch

Publications and source records attributed to R P Hirsch.

17 recordsLinked to original sources
PubMed1992

Stroke in China (Sino-MONICA-Beijing study) 1984-1986.

We present here the results of the Sino-MONICA-Beijing stroke study based on 700,000 Beijing residents in 1984-1986. To compare incidence rates for stroke with other communities and countries, we adopted the criteria of the WHO Collaborative Study of 17 centers which used the same definition and methodology as was used in this study. Over the 3-year period of the study, 2,593 stroke events were registered in the 25- to 74-year age-group. The incidence rate for all strokes was 189.5/100,000 and the incidence rate for first strokes was 133.6/100,000. Men had a significantly higher incidence rate than women (all strokes 219.7/100,000 for male vs. 160.5/100,000 for female, OR = 1.32, 99% limits 1.19-1.46; first strokes 151.6/100,000 for male vs. 116.4/100,000 for female, OR = 1.25, 99% limits 1.11-1.42). In comparison with other studies, age-adjusted incidence rate of stroke in Beijing was higher than in other countries, especially for hemorrhagic stroke. The proportion of hemorrhagic stroke related to other types of stroke was also higher in Beijing. Further analysis of the cases confirmed by computerized tomography also supported this finding. Unlike the incidence rates, the 4-week case fatality rate for women, 39.5%, was higher than for men, 32.8%. This finding was confirmed by a multiple logistic analysis controlling for age (p less than 0.001) and for previous stroke (p less than 0.001). The adjusted sex difference is also significant (OR = 1.37, p less than 0.001). In addition, results showed that men had a higher hospitalization rate than women. More women than men were treated at home, possibly indicating better medical care for men.

Adult↗
PubMed1991

Report of an association between race and thyroid stimulating hormone level.

We examined the association between race and thyroid stimulating hormone (TSH) level in 809 consecutive Black or White adults tested for mild suspicion of hypothyroidism with a normal TSH result. The mean TSH level of Blacks was 0.4 (SE .053) mU/L lower than that for Whites after age and sex adjustment, race explaining 6.5 percent of the variation in TSH levels. A validation sample yield similar results. This finding supports the possibility that differences in thyroid function and/or regulation may be associated with race.

Black People↗
PubMed1989

Yield of hypothyroidism in symptomatic primary care patients.

Symptoms suggestive of hypothyroidism are common in primary care practice, but the yield of this disorder from symptom-based testing has not been adequately evaluated. We attempted to determine this yield and examine the effect of various patient factors on its magnitude. The records of 982 consecutive primary care health maintenance organization patients who had a thyroid-stimulating hormone (TSH) determination for suspicion of hypothyroidism were reviewed. Forty-two (4.3%) had an increased TSH concentration on initial testing, but only 17 (1.7%) had a TSH level 5 mU/L or more above normal. Abnormal thyroid examination results and white vs black race were independently associated with a TSH concentration 5 mU/L or more above normal. Female sex and age did not significantly affect the odds of an elevated TSH concentration. The yield of hypothyroidism from symptom-based testing in this setting was quite low. Although increasing age and female sex are both strong determinants of the risk of hypothyroidism in the general population, neither factor permitted risk stratification in symptom-based testing. The strong racial association noted was not anticipated and requires confirmation.

Adult↗
PubMed1988

Fetal heart rate patterns during labor: neurologic and cognitive development at six to nine years of age.

The development of 50 children relative to the fetal heart rate patterns they demonstrated during labor and delivery was prospectively studied. Normal deceleration patterns were recorded for 12 of the children, while 16 were recorded as moderately severe and 22 as severe variable or late deceleration patterns. The parity and socioeconomic status of the mothers and the sexes of the infants were similar among the groups. A statistically significant developmental difference in favor of children with normal fetal heart rate patterns was seen in the first year of life. However, at 6 to 9 years of age the difference in neurologic and cognitive development was no longer evident. These data do not support the hypothesis that brief abnormal fetal heart rate patterns recorded during labor are indicative of irreversible central nervous system injury.

Achievement↗
PubMed1987

Calculation of odds ratios on the TI-59 from logistic regression output.

A program for the Texas Instruments TI-59 and, optionally, a print cradle is described that allows calculation of point estimates and confidence intervals for odds ratios using information included in the output from most logistic regression programs. The program considers up to fifteen continuous and/or dichotomous independent variables.

Biometry↗
PubMed1987

Evaluation of clinical and screening tests on the TI-59.

A program for the Texas Instruments TI-59 with print cradle is described that allows evaluation of the results expected, according to Bayes' theorem, when applying one or a series of clinical or screening tests. The results of testing are expressed in terms of predictive values and the probability of correctly classifying a patient. The program was written primarily for instruction of medical students and health professionals.

Bayes Theorem↗
PubMed1986

Bioimpedance measurement with respect to pulsatile pulmonary blood flow.

We used four-electrode electrical impedance plethysmography (IPG) to estimate regional pulmonary perfusion at three lung volumes, RV, FRC, and TLC. To define the region, the upright lung was divided into four equal sampling areas dorsally along the paravertebral space. The Kubicek formula was used to calculate pulmonary perfusion. Regional base resistance (Ro) decreased from the top to about 3/4 down the lung and then leveled off. The regional perfusion (Qz) showed an increase from the apex to about 3/4 down the lung and thereafter decreased toward the base, except at TLC. The regional distribution of the electrical derivative of resistance (dR/dt) resembled that of Qz because there was no statistically significant difference in ventricular ejection time or heart rate among studies. The value of the arithmetic sum of regional Ro was significantly larger than that of Ro for the total sampling field while the reverse was true for Qz. These discrepancies can be explained on the basis of the lead field theory applied to IPG. The regional perfusion gradient determined by IPG represents the pulsatile perfusion gradient in vivo because the outputs from the impedance analyzer are intimately linked to the pulse-synchronous pulsatile nature of pulmonary blood flow. Safe, simple, and noninvasive IPG can be used to study regional pulmonary perfusion in clinical situations, high altitude, or unusual environments.

Adult↗
PubMed1985

Cause of hearing loss in the high-risk premature infant.

Bilateral hearing loss occurred in 9.7% of infants who survived despite very low birth weight (less than or equal to 1500 gm), 16.7% of infants who survived neonatal seizures, and 28.6% of infants who survived both low birth weight and neonatal seizures. All neonates received treatment in a single neonatal intensive care unit between 1976 and 1980. Twenty-two of 36 hearing-impaired children were normal physically and mentally, with IQ scores of greater than or equal to 85. Significant neonatal predictors of hearing loss in high-risk premature infants (less than or equal to 36 weeks gestation), as determined by multivariable testing, were prolonged respirator care, high serum bilirubin concentration, and hyponatremia. Exchange transfusions were associated with a decreased risk of hearing loss.

Audiometry, Evoked Response↗
PubMed1978

Prevalence and distribution of Aeromonas hydrophila in the United States.

The abundance of Aeromonas hydrophila was measured in 147 natural aquatic habitats in 30 states and Puerto Rico. Viable cell counts were used to estimate density at all sites by using Rimler-Shotts medium, a differential presumptive medium for A. hydrophila. Temperature, pH, conductivity, salinity, and turbidity were measured simultaneously with water sample collection. The density of A. hydrophila was higher in lotic than in lentic systems. Saline systems had higher densities of A. hydrophila than did freshwater systems. A. hydrophila could not be isolated from extremely saline, thermal, or polluted waters, even though it was found over wide ranges of salinity, conductivity, temperature, pH, and turbidity. Of the water quality parameters measured, only conductivity was significantly regressed with density of A. hydrophila.

Aeromonas↗
PubMedDate not supplied

A computer model of denervation-reinnervation in skeletal muscle.

A computer model of the process of denervation and complete reinnervation of skeletal muscle has been developed for the purpose of exploring underlying mechanisms and for use in the development of new clinical and research tools for evaluating neuromuscular disease. Progressive motor neuron death and reinnervation in this model reproduces the fiber-type grouping, increased fiber density, and minimal increase of motor unit size seen in human chronic denervating diseases. Studies using the model suggest that (1) preferential involvement of motor units of one type could account for the abnormal fiber-type proportions observed in some diseases, (2) reinnervation by axons innervating adjacent fibers is compatible with single fiber multielectrode study results in that it does not produce a large increase in motor unit area, and (3) such reinnervation is sufficient to account for the increases in motor unit density that have been observed. The model has also been used in the development and testing of the Codispersion Index, a measure of the codistribution of two fiber types, which is useful in detecting fiber-type grouping.

Algorithms↗
PubMedDate not supplied

Non-returning patients: a survey of inactive patients in a suburban practice.

Maintaining an adequate patient volume is a new concern for primary care physicians. Retaining active patients may be as important as recruiting new patients. A mail survey was conducted using a random sample of patients not returning for care over a three-year period in a primary care office. Over half of the inactive patients were transient, never having established themselves with the practice. One third of regular attending inactive patients had changed physicians, whereas the others had simply not returned for care. Patients who had changed physicians were more likely users of emergency rooms or drop-in clinics, had more negative feelings while in physicians' offices, were less satisfied with their own present physicians, and had less positive attitudes toward physicians in general. Inactive patients who had not changed physicians were as satisfied with their own physicians and with physicians in general as the active patient control subjects, even though they used services infrequently, usually for acute care. Investigating transient patients and those who are inactive but remain with a practice would positively affect patient volume and would likely benefit these patients as well. Primary care physicians should survey their own inactive files before embarking on other marketing techniques.

Adult↗
PubMedDate not supplied

Inpatient experience of family practice residents in a community hospital.

Decisions regarding residency training require repeated reevaluation of organization and curriculum. Developing an autonomous inpatient teaching service may become necessary in many community hospitals because of a new competitive environment. To predict the impact of this possible change in one community program, we performed a retrospective analysis of 2,735 admissions to a community hospital during a one-year period. Residents' cases were compared with those of practicing family physicians and general internists. If family practice residents in this hospital were limited to an autonomous service, their overall experience and management of patients would be comparable to practicing primary care physicians in the same community hospital. However, volume would be inadequate and exposure to certain types of problems and situations would be limited. In multivariable analysis age, payment status, total consultation rate, many diagnostic categories, and some specific diagnoses separate residents from practicing physicians. As a particular example, internists have a concentration of geriatric patients and patients with cardiovascular disease. In order to utilize this experience, family practice residents in this hospital cannot rely solely on an autonomous teaching service.

Adolescent↗