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Biomedical subjects

J L Ross

Publications and source records attributed to J L Ross.

89 records · Page 5Linked to original sources
PubMed1984

Factor analysis as a tool in community diagnosis.

For the family physician, community diagnosis can be likened to individual diagnosis by the application of methods of information acquisition and analysis. This paper describes the technique of factor analysis, applied to data from an urban inner-city area, for reducing a multitude of factors to a manageable number without an appreciable loss of information. The variables were selected from four broad categories which have been shown to influence both health states and health care needs: demography, socioeconomics, social disorganization and morbidity/mortality. A correlation matrix based on 40 of the most accessible indices served as input for a principal axes factor analysis. Six factors accounted for 74% of the total variance and were interpreted as: 'Poverty and social disorganization', 'Distribution and problems of the elderly', 'Ethnic composition', 'Fertility', 'Infant mortality' and 'Foetal mortality'. Representative indices from each factor were then mapped to identify and display census tract differences. Finally, the application of the factors to a specific community illustrated important differences within the community and identified areas of high risk and need.

Factor Analysis, Statistical↗
PubMed1984

Absence of pubertal gonadotropin secretion in girls with McCune-Albright syndrome.

Precocious puberty in girls with McCune-Albright syndrome has been attributed in some cases to early activation of the hypothalamic-pituitary-gonadal axis and in other cases to sex steroid secretion by apparently autonomous ovarian cysts. We evaluated serum gonadotropins and sex steroids in six girls (aged 1-9 yr) with McCune-Albright syndrome. The children had Tanner stage II-IV pubertal development. In five patients, nocturnal gonadotropin concentrations and the gonadotropin response to LHRH were within the normal range for prepubertal children. Thus, the precocious puberty in these patients could not be explained by activation of the hypothalamic-pituitary-ovarian axis. One child had high amplitude nocturnal pulses of serum LH and a LH-predominant response to LHRH. She was the oldest of the six girls and had a bone age of 13.5 yr which is within the range in which hypothalamic-pituitary-ovarian activation normally occurs. The children all had ovarian enlargement and ovarian cysts determined by ultrasound. It appears that precocious puberty in McCune-Albright syndrome may result from ovarian estrogen secretion in the absence of normal pubertal activation of the hypothalamic-pituitary-ovarian axis.

Adolescent↗
PubMed1984

Variable response to a long-acting agonist of luteinizing hormone-releasing hormone in girls with McCune-Albright syndrome.

Six girls with McCune-Albright syndrome were treated for at least 2 months with the long-acting LHRH agonist D-Trp6-Pro9-NEt-LHRH, which previously was found to be an effective treatment for true precocious puberty. Nocturnal and LHRH-stimulated serum gonadotropin levels and plasma estradiol levels were measured before treatment and after 2-3 months of treatment. Five of the six girls had no decrease in serum gonadotropin or plasma estradiol levels during therapy, and their pubertal signs were unaffected by treatment. All five of these girls had serum gonadotropin levels that were within or below the normal prepubertal range. The sixth girl, who had gonadotropin levels in the normal pubertal range before treatment, had decreased serum gonadotropin and plasma estradiol levels during 1 yr of LHRH analog therapy. This was associated with cessation of menses and regression of secondary sexual changes. The failure of LHRH analog to modify the course of precocious puberty in the five patients with prepubertal serum gonadotropin concentrations is further evidence that the mechanism of precocious puberty in most girls with McCune-Albright syndrome differs from that in patients with true precocious puberty.

Child↗
PubMed1984

A comparison of two methods for detecting hormone peaks: the effect of sampling interval on gonadotropin peak frequency.

There is no consensus on the optimum method to identify gonadotropin pulses in serum. We compared two approaches for detecting gonadotropin peaks. The first employed the conventional criterion of an increment from nadir to peak of 3 times the intraassay coefficient of variation (3 CV). The second identified peaks by Student's t test to quadruplicate measurements at each time point. We obtained blood samples every 5 min for 6 h from four women in the follicular phase. We also constructed control or noise series by subdividing single serum pools into consecutively labeled aliquots. Any variations in hormone concentration in the noise series that were identified as peaks were, by definition, false positive peaks. We evaluated the effect of sampling interval on gonadotropin peak detection by omitting data to simulate sampling every 10, 15, or 20 min. The 3 CV approach identified numerous false positive peaks in the noise series and detected as many peaks in the noise series as it did in the patient series. Increasing the sampling frequency from every 20 to every 5 min nearly doubled the apparent peak frequencies in both the patient and the noise series (P less than 0.025). By contrast, the t test method detected far fewer false positive peaks and significantly more peaks in the patient series than in the noise series. Increasing the sampling frequency from every 20 to every 5 min resulted in a 50-75% increase in peak frequency by the t test method. This increase in peak frequency appeared to result from improved detection of small peaks, because samples were obtained nearer the true peaks and nadirs. The resulting increase in the nadir to peak increment made it more likely that a small peak would achieve statistical significance. We conclude that increasingly stringent criteria for pulse detection should be applied as one increase the sampling frequency, and that the t test approach is a more valid method than the 3 CV approach because it yields significantly fewer false positive peaks.

Adolescent↗
PubMed1983

Social and economic forces affecting intergenerational relations in extended families in a Third World country: a cautionary tale from South Asia.

This paper questions the implicit assumption derived from modernization theory that elderly persons in the Third World lead secure and satisfying lives because they still live in extended families. Data from elderly Hindus living in Kathmandu, Nepal, are presented and demonstrate that, although these elderly people do continue to live in extended families, social and economic changes have transformed the nature of intergenerational social relations within these families to the detriment of the elderly family members.

Aged↗
PubMed1983

Developmental changes in neuroendocrine regulation of gonadotropin secretion in gonadal dysgenesis.

Patients with gonadal dysgenesis have a marked increase in gonadotropin levels at the age when puberty normally occurs. To determine whether this increase results from a change in the frequency or the amplitude of gonadotropin pulses, we measured the 24-h profile of plasma LH and FSH by RIA in 31 patients with gonadal dysgenesis, aged 2-20 yr. Gonadotropin pulses were defined as a rise from nadir to peak that exceeded 3 times the intraassay coefficient of variation. This criterion, based on an empirical study of RIA noise, reduced the rate of false positive peaks to less than 3-4/24 h. Using this criterion, peak amplitude increased significantly at the time of puberty for both LH and FSH (P less than 0.01). The overall frequency of gonadotropin pulses (the sum of the FSH peaks plus the LH peaks that occurred without a concomitant FSH peak), however, did not differ among prepubertal (12.7 +/- 1.8 peaks/24 h), pubertal aged (14.3 +/- 2.3 peaks/24 h), and adult patients (14.7 +/- 0.9 peaks/24 h). Thus, the increase in gonadotropin concentration in pubertal aged patients with gonadal dysgenesis appears to result primarily from an increase in gonadotropin peak amplitude rather than an increase in peak frequency.

Adolescent↗
PubMed1978

Massive osteolysis. An unusual cause of bone destruction.

A patient who presented with multiple lytic lesions of bone was found to have massive osteolysis. The clinical course of this patient is described and the literature on massive osteolysis reviewed. This disease of uncertain etiology is pathologically marked by resorption of bone, and replacement by angiomas and fibrosis. X-ray findings are usually more severe than expected from the patients' clinical presentation. Laboratory studies, including attempts at biopsy, are generally unrevealing. Drug therapy is of no value, and success of surgical attempts at bone union are unpredictable. Massive osteolysis should be considered in the differential diagnosis of osteolytic lesions, particularly since this disorder can result in serious morbidity.

Bone Neoplasms↗
PubMedDate not supplied

Prevention of a first stroke: a review of guidelines and a multidisciplinary consensus statement from the National Stroke Association.

OBJECTIVE: To establish, in a single resource, up-to-date recommendations for primary care physicians regarding prevention strategies for a first stroke. PARTICIPANTS: Members of the National Stroke Association's (NSA's) Stroke Prevention Advisory Board and Cedars-Sinai Health System Department of Health Services Research convened on April 9, 1998, in an open meeting. The conference attendees, selected to participate by the NSA, were recognized experts in neurology (9), cardiology (2), family practice (1), nursing (1), physician assistant practices (1), and health services research (2). EVIDENCE: A literature review was carried out by the Department of Health Services Research, Cedars-Sinai Health System, Los Angeles, Calif, using the MEDLINE database search for 1990 through April 1998 and updated in November 1998. English-language guidelines, statements, meta-analyses, and overviews on prevention of a first stroke were reviewed. CONSENSUS PROCESS: At the meeting, members of the advisory board identified 6 important stroke risk factors (hypertension, myocardial infarction [MI], atrial fibrillation, diabetes mellitus, blood lipids, asymptomatic carotid artery stenosis), and 4 lifestyle factors (cigarette smoking, alcohol use, physical activity, diet). CONCLUSIONS: Several interventions that modify well-documented and treatable cardiovascular and cerebrovascular risk factors can reduce the risk of a first stroke. Good evidence for direct stroke reduction exists for hypertension treatment; using warfarin for patients after MI who have atrial fibrillation, decreased left ventricular ejection fraction, or left ventricular thrombus; using 3-hydroxy-3 methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors for patients after MI; using warfarin for patients with atrial fibrillation and specific risk factors; and performing carotid endarterectomy for patients with stenosis of at least 60%. Observational studies support the role of modifying lifestyle-related risk factors (eg, smoking, alcohol use, physical activity, diet) in stroke prevention. Measures to help patients improve adherence are an important component of a stroke prevention plan.

Alcohol Drinking↗
PubMedDate not supplied

Noonan's syndrome and hypopituitarism.

A 37-year-old man with Noonan's syndrome hypopituitarism is described. The patient had small stature, minor facial abnormalities, cubitus valgus and pectus excavatum. In addition, endocrine testing revealed deficiencies of growth hormone, gonadotrophins and TSH. Prolactin increased normally in response to TRH administration, but failed to rise after chlorpromazine. Although intrinsic pituitary dysfunction cannot be excluded, the dissociated response of prolactin to TRH and chlorpromazine suggests that the pituitary hormone deficiencies may be secondary to hypothalamic dysfunction.

Adult↗
PubMedDate not supplied

Hemodialysis arteriovenous fistulas: a nineteenth century view of a twenty first century problem.

This is a literature review which approaches the problem of successful use of arteriovenous fistulas for dialysis within the construct of Virchow's triad. By organizing the literature with regard to Virchow's concepts of blood flow, vascular injury, and thrombophilia an improved understanding arteriovenous fistula placement, maintenance and repair can be obtained. This process is designed to increase understanding and options for treatment by looking at this problem and using scientific knowledge gained in cardiology, oncology and vascular surgery medicine. Future approaches to fistulas will hopefully be a multifaceted and based in cellular pathophysiology as well as surgical and radiologic interventions and repairs.

Journal Article↗
PubMedDate not supplied

Systems analysis and guidelines for behavioral scientists in family medicine.

A recurrent theme among behavioral scientists is the difficulty of being a nonphysician in a medical setting. Differences in training and in work roles can create misunderstanding between physicians and behavioral scientists; and being a minority in terms of profession can be isolating and demoralizing. To date, analyses have focused on the individual differences between the two groups and not on the context--the larger system--in which the two work. This article examines these systemic problems, particularly problems specific to family medicine. Coping methods which can be used by behavioral scientists are proposed to help them reduce the work stress they experience.

Behavioral Sciences↗
PubMedDate not supplied

Physician-patient power struggles: their role in noncompliance.

Physicians have tended to label the patient who doesn't follow their advice as resistant and noncompliant. However, compliance studies have not identified the physician's sometimes unwitting complicity in the noncompliance. Some physician-patient partnerships are marked by an intensifying power struggle which may have more to do with the emotional needs of each party than with the specific content around which the struggle is focused. This article discusses how these power struggles can be activated and what the physician can do to defuse the struggle and work effectively with noncompliant patients.

Humans↗