Biomedical subjects
Publications and source records attributed to R T Brown.
The influence of physiologic, psychologic, and cultural influences on human sexuality is reviewed. These factors are considered in the exploration of how adolescents express their sexuality and the consequences of that expression.
This study of attention-deficit-disordered children revealed that females were more frequently retained in school and evidenced greater impairment on spatial memory tasks. Moreover, there was a trend for girls to be older at the time of referral. With age, the girls evidenced more severity across a wider array of measures, including cognitive functioning, poorer academic achievement, and more problems with peers.
We studied 45 patients who had autonomic failure with computed tomography, magnetic resonance imaging and positron emission tomography with [18F]fluorodeoxyglucose to characterize the neuroimaging features of multiple system atrophy and pure autonomic failure and determine the utility of these techniques in distinguishing multiple system atrophy from pure autonomic failure. There were 30 patients with multiple system atrophy and 15 with pure autonomic failure. In the multiple system atrophy group, eight patients had mainly cerebellar signs, seven extrapyramidal and 15 had combinations of cerebellar and extrapyramidal signs. Cerebellar atrophy on computerized tomography and magnetic resonance imaging, signal hypointensity in the posterolateral putamen on magnetic resonance imaging and a generalized reduction in glucose utilization rate with positron emission tomography with [18F]fluorodeoxyglucose, were the main findings and were seen only in the patients with multiple system atrophy. Decreased glucose utilization (hypometabolism) was most prominent in the cerebellum, brainstem, striatum and frontal and motor cortices. These results indicate clear differences, using neuroimaging studies, between multiple system atrophy and pure autonomic failure.
Explore the source record for details and available documents.
The psychiatric functioning of 28 youths with insulin-dependent diabetes mellitus was examined. Measures of psychological functioning were related to age at onset, duration of diabetes, and metabolic control, as assessed by HgbAlC. Children diagnosed with insulin-dependent diabetes mellitus at a later age were considered by teachers to have more behavioral problems. Children who had better metabolic control tended to hold themselves responsible for negative events. It is worthwhile to develop interventions to teach diabetic children a realistic balance between taking appropriate responsibility for controllable negative events without taking undue blame for uncontrollable negative events associated with the disease.
Increased plasma adrenalin (A) levels following arecoline in normal subjects and patients with multiple system atrophy (MSA) may result from nicotinic adrenal stimulation. Lack of this response in patients with pure autonomic failure (PAF) is consistent with peripheral sympathetic dysfunction. The mechanisms underlying diminished plasma corticotropin (ACTH) responses to arecoline may differ in patients with autonomic failure. Hypothalamic, cholinergic degeneration could prevent the response in MSA whereas patients with PAF do not manifest the normal increase in A which may be required to elicit an ACTH response. The appearance and exacerbation of tremor, vertigo, and pathological affect in the MSA group suggest that some central cholinergic receptors remain functional.
We examined the cardiovascular, plasma norepinephrine (NE), and plasma renin (PRA) responses to isoproterenol infusion in patients with autonomic failure and in normal subjects. Slopes of the blood pressure response/dose relationships were more negative in patients with multiple system atrophy and pure autonomic failure (PAF) than in normal subjects, consistent with impaired baroreflex modulation. A shift to the left in patients with PAF suggests beta-adrenergic receptor supersensitivity. In normal subjects, the increase in plasma NE and PRA was proportional to the log of the plasma isoproterenol level. Isoproterenol infusion did not increase plasma NE or PRA in either patient group despite a reduction in mean blood pressure. Reflexive cardiovascular and renal mechanisms appear to play a role in eliciting the plasma NE and PRA responses to isoproterenol infusion in normal subjects.
Explore the source record for details and available documents.
We did not find a significant association between HLA antigens and pure autonomic failure or multiple system atrophy with autonomic failure. HLA-A32, specifically, did not occur with increased frequency in either group of patients. Our results do not support an HLA contribution in these disorders of the autonomic nervous system as reported by other investigators.
Patients with neurogenic orthostatic hypotension can have deficits in sympathetic neural function at any of several levels of the sympathetic neuraxis. We determined whether patterns of plasma levels of dopa, norepinephrine, dihydroxyphenylglycol, and dihydroxyphenylacetic acid would distinguish patients with orthostatic hypotension associated with multiple system atrophy, pure autonomic failure, or deficiency of dopamine-beta-hydroxylase. Plasma levels of catechols were normal in most patients with multiple system atrophy, consistent with relatively intact peripheral sympathetic neurons; in contrast, most patients with pure autonomic failure had decreased levels of all four catechols, consistent with degenerative loss of sympathetic nerve endings. Patients with deficiency of dopamine-beta-hydroxylase had increased levels of dopa and dihydroxyphenylacetic acid and markedly decreased levels of norepinephrine and dihydroxyphenylglycol, suggesting compensatory increases in sympathetic nerve activity in the absence of norepinephrine biosynthesis. Subgroups of patients with pure autonomic failure or multiple system atrophy had low levels of norepinephrine with normal levels of dopa, dihydroxyphenylglycol, and dihydroxyphenylacetic acid, consistent with normal catecholamine biosynthesis and decreased postganglionic sympathetic nerve traffic or decreased exocytotic release from sympathetic nerve endings. The results demonstrate the value of examining patterns of plasma levels of catechols to elucidate mechanisms of neurogenic orthostatic hypotension.
The short-term dose effects of methylphenidate were examined on cardiovascular measures in 11 black male adolescents diagnosed as having attention deficit hyperactivity disorder (ADHD). In a double-blind, cross-over design with randomized order, the subjects received placebo and each of three methylphenidate doses (0.15, 0.3, and 0.5 mg/kg) for a period of 2 weeks per medication dosage. Significant main effects were found for diastolic and systolic blood pressure; however, pairwise comparisons revealed a significant linear increase in diastolic blood pressure only. Because of the unexpected increase in diastolic blood pressure, careful monitoring of black adolescents who are receiving methylphenidate is recommended.
Explore the source record for details and available documents.
Thirteen patients who had undergone thyroidectomy for thyroid cancer stopped thyroid hormone replacement prior to follow-up radioactive iodine scans. Thyroxine was replaced by triiodothyronine (T3) for 4 weeks and T3 was stopped 2 weeks before the scan and 16 to 19 days before blood pressure measurement and venipuncture for obtaining plasma noradrenaline samples. During this time, a small but significant decrease in systolic blood pressure occurred, both supine and standing, while the corresponding plasma noradrenaline levels increased significantly. These findings indicate that the acute cardiovascular effect of brief thyroid hormone withdrawal is a decrease in blood pressure rather than the increase often observed in chronic hypothyroidism, and that plasma noradrenaline levels may increase much sooner than previously reported after onset of hypothyroidism.
The present study examined the perceptions of parents of children with attention deficit disorder with hyperactivity (ADD/H) regarding their family environment and depression in comparison with a clinical and a nondisabled control group. Parents of children with ADD/H perceived their family environment as less supportive and more stressful than did either the clinical or the nondisabled controls. Specifically, ADD/H parents viewed their families as having lower levels of interpersonal relationships than did either of the control groups. Ratings of depression for each of the parent groups indicated a greater frequency of depressive symptomatology among the parents of children with ADD/H. In addition, more parents of ADD/H children were separated or divorced. Correlation coefficients computed for the entire sample suggest differences between mothers' and fathers' depression and differences in their perceptions of the family. Recommendations are made for future research as well as the development of treatment programs to incorporate work with the parents of children with ADD/H.
Diminished CSF levels of acetylcholinesterase in patients with multiple system atrophy attended by autonomic failure suggest that CNS cholinergic involvement may occur in this disorder. The lack of correlation between the low enzyme levels and low CSF levels of monoamine metabolites in these patients indicates that the acetylcholinesterase reduction is not directly related to disruption in these neurotransmitter systems. Normal CSF acetylcholinesterase levels in those patients with pure autonomic failure are consistent with functional integrity of central cholinergic pathways and support a pathophysiologic involvement limited to the peripheral nervous system.
A prospective study was performed to examine the prevalence of pharyngeal gonorrhea in two urban female adolescent populations and to compare pharyngeal infection with a history of orogenital activity and concurrent genital gonorrhea. Group I was drawn from a children's hospital adolescent clinic and group II was drawn from a public health clinic for sexually transmitted diseases. None of the 240 adolescents in group I had a pharyngeal culture positive for Neisseria gonorrhoeae compared with 3.4% in group II. Only 2.5% of group I had genital gonorrhea, but 33% of group II had positive genital cultures. In only two of the 20 patients with pharyngeal gonococcal infection was the pharynx the only infected site. The addition of routine pharyngeal culturing for gonorrhea yielded only 1% additional gonorrhea cases. There was a significant relationship between concurrent genital and pharyngeal gonorrhea. These findings indicate that routine screening for pharyngeal gonorrhea is not productive in some adolescent populations. A more economic approach would be to use gonorrhea treatment that is effective against both genital and pharyngeal gonorrhea or to obtain pharyngeal cultures in those adolescents returning for test-of-cure cultures after antibiotic treatment for genital gonorrhea.
Explore the source record for details and available documents.
Explore the source record for details and available documents.