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Biomedical subjects

R Boyer

Publications and source records attributed to R Boyer.

At least 19 recordsLinked to original sources
PubMed1992

Understanding physicians' decision to perform a clinical examination on an HIV seropositive patient.

The main purpose of this study was to identify the psychosocial factors explaining a physician's decision to perform a clinical (physical) examination of an HIV seropositive patient. Eight hundred seventy-nine physicians completed a questionnaire investigating psychosocial variables derived from the theories of Ajzen and Triandis. The mean intention to perform a clinical examination was quite positive (5.4 on a 7-point scale). The regression of intention on all variables yielded an adjusted R2 of .499. Among few significant predictors, by far the most important was the perceived norm among fellow physicians regarding performance of the clinical examination. It is concluded that educational interventions aimed at the physician population should focus on the social role and personal efficacy of physicians regarding this type of clinical examination rather than giving information concerning the low risk of contracting the HIV.

Attitude of Health Personnel↗
PubMed1992

[Decrease of pineal AMPc and TOH activity in the superior cervical ganglia after ablation of submaxillary glands in rats].

In order to investigate a possible functional relationship between the submandibular salivary gland (SSG) and the central nervous system (CNS), we have extirpated the salivary organs from thirty male rats. Twenty days after ablation both the pineal glands and the cervical superior ganglions (CSG) were dissected, homogenized and frozen until AMPc and TOH were assayed respectively. We observed a significant decrease in pineal AMPc (53.9 +/- 6.2 vs 76.1 +/- 7.6% of maximum value; p less than 0.02) which seems to be linked with a significant drop in TOH activity measured at CSG level (1.5 +/- 0.6 vs 3.7 +/- 0.9 nmoles of DOPA/h/pair GCS; p less than 0.03). Our results suggest that both findings might be due to the lack of NGF normally reaching the CSG from SSG. This data reinforces the idea of a functional link between SSG and CNS via the pineal gland.

Animals↗
PubMed1991

[Resection of hepatocarcinomas in liver cirrhosis: the value of intraoperative echography].

In the last 3 years 21 cirrhotic patients with hepatocellular carcinoma were operated. All patients fulfilled the criteria of localized tumor and good liver function and underwent a laparotomy with the aim of resecting the tumor. Intraoperative ultrasound examination was essential to localize a non visible and non palpable tumor in 2 cases and it was useful to detect other nodules in 3 of the 16 patients who underwent a hepatic resection of the tumor. In 5 patients resection was considered not indicated. Therefore, the initial therapeutic approach of tumoral resection was changed in 23.8% of patients. Also, intraoperative ultrasonography was essential for performing a guided resection of hepatocellular carcinomas in cirrhotic liver with the aim of preserving as much liver parenchyma as possible.

Aged↗
PubMed1991

[A non-exocrine function of the submaxillary gland].

Emphasizing on the concept of "banalization" and multifactoriality of the signal molecules of the cellular communication, the authors review data of the literature which allow to attribute to some substances synthetized by the submandibular salivary glands (SSG), mainly growth factors as EGF and NGF, an endocrine role. Because of their direct secretion in the oral cavity or their overflow into bloodstream the consequences of the deficit of these growth factors could be correlated with some oral pathologies such as aphthous lesions, puberty and pregnancy gingivitis, which endocrine etiology is often assumed, as well as autoimmune salivary pathologies. Thus, the results obtained after SSG removal furnish a support for envisaging a link between the submandibular salivary glands and the reproductive function (decrease in plasma LH level, ultrastructural changes of the Leydig cells, spontaneous abortion) and with some structures of the central nervous system such as hypothalamus (variation in hypothalamic TRH content) or pineal gland (decrease in pineal cyclic AMP content). Particularly interesting is the possibility that NGF secreted in blood by the SSG during a stress may represent the signal able to stimulate the peripheral immunity cells as well as to inform the central nervous system through a neuronal pathway via the superior cervical ganglia and the pineal gland. This brain afferent information could be associated with an increased hypothalamic NGF synthesis, also observed during stress, whose finality might be to stimulate the secretion of hypophyseal ACTH, the main hormone involved in the interrelationship between endocrine and immune response.

Animals↗
PubMed1990

Ablation of submandibular salivary glands in rats provokes a decrease in plasma luteinizing hormone levels correlated with morphological changes in Leydig cells.

This work was designed to determine whether changes in plasma and hypophyseal levels of LH are the source of the previously reported atrophy of testicular interstitial tissue following ablation of submandibular salivary glands. The plasma and hypophyseal levels of LH were assayed, and testicular sections examined by electron microscopy in rats, weighing 230-260 g, whose submandibular glands had been removed. Twenty days after sialectomy, the rats were killed, and the pituitary glands removed, homogenized and frozen until used in LH-RIA like the blood samples. Testes were removed and fixed in osmic acid. There was a significant decrease in plasma LH levels in operated animals when compared with sham-operated controls (47.28 +/- 7 ng/ml versus 70.42 +/- 8; p less than 0.02), but the hypophyseal LH content was not significantly modified. Electron microscopy mainly showed important changes in the morphology of the Leydig cells, with a distinct reduction in the number of mitochondria and elements of the smooth endoplasmic reticulum. These findings suggest a physiological involvement of submandibular glands in a possible endocrinological link with the gonadotropic axis.

Animals↗
PubMed1990

[On the epidemiology of mental illnesses: update on recent data].

The goal of this paper is to summarize recent epidemiological findings from community studies on mental illness prevalence and incidence among male and female respectively. The author refer mainly to the Epidemiological Catchment Area (ECA) research projects. A review of developments of the American Psychiatric Association classification of mental disorders is presented and implications of the new nosology on the epidemiologic method is offered. The data indicate that males and females vary significantly in prevalence and incidence of psychopathologies assessed in these studies. Results are compared to those collected for the Santé Québec health survey.

Catchment Area, Health↗
PubMed1989

Anxiety disorders among Mexican Americans and non-Hispanic whites in Los Angeles.

This report from the Los Angeles site of the NIMH Epidemiologic Catchment Area study reveals significant ethnic and national origin differences in lifetime prevalence rates for three out of six specific, DSM-III-defined anxiety disorders. In the case of simple phobia, United States-born Mexican Americans report higher rates than native non-Hispanic whites or immigrant Mexican Americans, the latter two groups having similar rates. Mexican Americans born in the United States had higher rates of agoraphobia than immigrant Mexican Americans, and non-Hispanic whites reported higher lifetime rates of generalized anxiety disorder compared with both immigrant and native Mexican Americans. Neither ethnic nor national origin differences in lifetime prevalence rates were found for panic disorder, social phobia, and obsessive-compulsive disorder. Selective migration is postulated as a potential factor influencing prevalence differences between native and immigrant Mexican Americans.

Anxiety Disorders↗
PubMed1988

Decrease of hypothalamic TRH levels but not plasmatic TSH levels after ablation of submandibular salivary glands in the rat.

Indirect relationships are thought to exist between submandibular salivary glands (SSG) and the central nervous system (CNS) via superior cervical ganglia (SCG). To study this topic, the concentrations of thyrotropin releasing hormone (THR) and somatostatin (SRIF) were measured in both whole and specific areas of the hypothalamus, as well as plasmatic thyrotropin stimulating hormone (TSH) levels following ablation of SSG. Twenty, forty and fifty days after ablation of SSG, groups of operated and sham-operated animals weighing 230-260 g at the beginning of experimentation, were killed by cervical dislocation. Plasma was taken, frozen and stored for TSH-radioimmunoassay (RIA) and the hypothalami were removed and homogenized in either 0.1 N HCl (for TRH-RIA) or 0.2 N acetic acid (for SRIF-RIA). Twenty days after ablation of SSG in another group, TRH concentrations were measured in both the median eminence (ME) and the paraventricular nucleus (PVN), dissected by the micropunch technique. The results show that twenty days after SSG ablation, the hypothalamic TRH concentrations was significantly lower in operated than in sham-operated animals (295.2 +/- 24.8 vs 226 +/- 11.15 pg/mg hypothalamus respectively p less than 0.01, n = 9). No differences were observed at later intervals. This finding seems to be specific for this peptide since the SRIF level was not modified twenty days after SSG removal. Among the discrete hypothalamic areas examined, only the ME exhibited a significant decrease in TRH content (25.43 +/- 3.02 ng/mg prot. VS. 41.24 +/- 1.33 ng/mg prot., respectively). Despite these results on TRH levels, no modifications in plasmatic TSH levels were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Perceived health status among the new urban homeless.

Homelessness may be the leading social problem in the United States in the mid 1980s. While there may be anywhere from 250,000 to three million homeless persons, few empirically based published studies are available concerning the correlates of mental and physical health status among the homeless. Los Angeles, where the present study was conducted, has been designated by the U.S. Department of Housing and Urban Development to have one of the largest homeless populations (34,000-50,000) in the U.S. The current study is based on 269 in-depth interviews with homeless men and women in Los Angeles County, California. The homeless were found to be younger, better educated and disproportionately non-white compared to the profiles of the skidrow homeless of the past decades. Nearly half the men were veterans of military services, including 30% who were veterans of the Vietnam War. Respiratory infections and hypertension were the most prevalent health problems. The data suggest that a large segment of the homeless persons were depressed, 15.6% reported lifetime prevalence of hospitalization for emotional or nervous problems, and 12.6% reported hospitalization for substance abuse disorders. Multiple regression was utilized to test the validity of a perceived health status index as measured among the homeless and to identify the correlates of health. The health index reflect primarily an affliction by a chronic disease, the severity of an acute condition, the duration of depressed mood, and the alcoholism symptomatology. Length of unemployment, education, gender, and number of nights spent in a shelter were the best predictors of poor health in this population. Evidence from this study, as well as others, suggests that efforts should be made to avoid using the term homeless metaphorically. The causes of homelessness are multiple and complex and the resulting subgroups among the homeless population have different problems which require a variety of strategies to meet their needs.

Adult↗
PubMed1986

Effect of submandibular salivary gland removal on body weight, plasmatic testosterone levels, testicular weight and spermatogenesis in rats.

In this work we report the effect of the removal of submandibular salivary glands (S.S.G.) on plasmatic testosterone levels and other aspects of testicular function and on body weight in rats. Our results were obtained with 72 male rats weighing 230-260 g whose S.S.G. were removed. At only twenty days after removal a slight but significant decrease (p less than 0.05) of testicular absolute weight (3.431 +/- 75 mg vs 3.612 +/- 53 mg) was detected. This decrease was probably due to atrophy of interstitial tissue, as revealed by histological examination. In contrast, neither plasmatic testosterone (T) levels nor spermatogenesis (S.P.G.) were altered. The effect on testicular weight at twenty days was not closely associated with the effect on body weight. Changes in this latter parameter were observed twenty days after extirpation of S.M.G. (107 +/- 5.5 vs 124 +/- 4.3 g; p less than 0.02) and up until forty days (175.6 +/- 4.1 g vs 202.8 +/- 5.5; p less than 0.05) after S.S.G. removal. Difference in gain of body weight is not influenced by nutritional lack, as shown by the fact that nutritional absorption is not modified in the operated animals controlled in wire bottom cages. These data suggest that S.S.G. right play a trophic regulatory role, separately, on testes and body without the mediation of T. The direct involvement of biological peptides contained in S.S.G. is discussed.

Animals↗
PubMed1985

Supratentorial ependymoma: CT appearance.

The computed tomographic appearances of 22 biopsy-proved supratentorial ependymomas were analyzed. Supratentorial ependymomas were usually intraparenchymal, larger than 4 cm, and cystic. Contrast enhancement was moderate to intense, with homogeneous or ring-enhancement patterns commonly seen. Intratumoral calcification was present in one-third of the cases, while hydrocephalus and peritumoral edema were seen in 50%. Intratumoral hemorrhage was not a characteristic of the lesion. In contrast to cellular ependymomas, malignant ependymomas and ependymoblastomas demonstrate higher attenuation prior to administration of contrast material, more intense enhancement, lower frequency of calcification within the tumor, and less distinct margination.

Adolescent↗
PubMed1984

In vivo release of somatostatin from rat median eminence after local K+ infusion or delivery of nociceptive stress.

The effects of local infusion of a 16 mM K+ solution or of a nociceptive stress on the release of somatostatin (SRIF) from the hypothalamus was measured in unanesthetized male rats implanted with a push-pull cannula in the median eminence. Although the baseline secretion rate of SRIF was increased in animals displaying agitation as a result of handling stress, both treatments induced fast doubling of SRIF release lasting for 15-30 min. Neither an equimolar Na+ infusion into the median eminence nor a similar K+ infusion into the 3rd ventricle had any affect on this release. The possible role of SRIF release in the mechanism of growth hormone inhibition following nociceptive stress is discussed.

Animals↗