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Biomedical subjects

R T Brown

Publications and source records attributed to R T Brown.

At least 19 recordsLinked to original sources
PubMed1992

Chemotherapy for acute lymphocytic leukemia: cognitive and academic sequelae.

Iatrogenic cognitive impairments have been reported for survivors of childhood leukemia after prophylactic central nervous system therapy with craniospinal radiation. To determine whether chemotherapy alone might be a source of central nervous system damage, we assessed in a cross-sectional design the cognitive and academic functioning of 48 children with acute lymphocytic leukemia who were at various stages in their treatment or who had completed treatment. The off-therapy patients who had completed a 3-year course of chemotherapy were more impaired in tasks of higher-order cognitive functioning than were those children whose leukemia had been newly diagnosed and those children whose diagnoses had been 1 year earlier. Off-therapy patients also had concomitant diagnosable learning disabilities in mathematics. We recommend appropriate liaison and special education placements, as well as continued evaluation of cognitive and leaning functioning of children treated for moderate-risk acute lymphocytic leukemia who receive chemotherapy alone.

Achievement↗
PubMed1992

Psychiatric and family functioning in children with leukemia and their parents.

The present study reports data from a cross-sectional investigation of the psychiatric and psychosocial functioning of 55 children diagnosed with acute lymphocytic leukemia and their families at three points in time: diagnosis (newly diagnosed), 1 year postdiagnosis, and 1 year after the completion of chemotherapy (off-therapy). Results reveal minimal psychopathology in these children and their parents based on self- and informant-reports and structured diagnostic interviews. These families appear to be functioning adequately and report more family cohesiveness and marital satisfaction after chemotherapy was completed. Coping strategies commonly used by children and their parents include problem-solving, a positive outlook, and good communication. Implications for psychiatric consultation are presented.

Adaptation, Psychological↗
PubMed1992

Compliance with breast self-examination instruction in high school students.

In a prospective study, we measured compliance with breast self-examination, using an anonymous questionnaire, in suburban high school students three months (n = 85) and eight months (n = 54) after group instruction. Post-instruction proficiency in performing the procedure and personal health beliefs regarding breast cancer were also evaluated. At three months, 40% of the group reported practicing breast self-examination at some time since instruction; 12% had performed the procedure timed correctly with their menstrual cycle. At eight months, only two girls (4%) had practiced breast self-examination at least once since the three-month evaluation. Proficiency scores overall were high, with 77% scoring 12 points or above on a 15-item questionnaire; however, scores were significantly lower in the 15-year-olds than in the older adolescents. No significant relationships were found between compliance and most personal health beliefs, previous instruction, or level of knowledge of the procedure. Attention should be directed toward assessing the ability and willingness to practice preventive health behaviors before instruction programs are instituted in this age group.

Adolescent↗
PubMed1992

Update on pregnancy, condom use, and prevalence of selected sexually transmitted diseases in adolescents.

Adolescent pregnancy and its consequences continue as major sources of morbidity in the United States. A teenager who becomes a parent is at a significant disadvantage in becoming a contributing adult, both psychosocially and economically. The physician who cares for adolescents has the responsibility of helping parenting teens to find needed support so that they will be able to overcome this significant hurdle. Attention from public agencies has focused on increasing condom use as one approach to adolescent pregnancy prevention. The major advantage of using condoms is that they also prevent transmission of sexually transmitted diseases. Of note is that level of knowledge about condoms is not related to their use, and engaging in high-risk behaviors is related to a decreased likelihood of condom use. With rates of condom use estimated at less than 50%, rates of sexually transmitted disease remain high, as reported in recent surveys.

Adolescent↗
PubMed1992

A comparison of never-hospitalized and previously hospitalized adolescents: self-esteem and locus of control.

Few empirical studies have been conducted to determine the influence of hospitalization on adolescents' psychosocial processes because younger children are regarded as more vulnerable. Therefore, the purpose of this self-report, retrospective study of 115 adolescents was to compare the self-esteem and locus of control of the never hospitalized to that of adolescents hospitalized during adolescence, prior to adolescence, and during and prior to adolescence. Although no significant differences were found, the findings raise questions about long-term effects of early experiences, especially among lower socioeconomic status youth. Also, general measures of self-esteem and locus of control may be unable to determine situation-specific effects.

Adolescent↗
PubMed1992

Adolescent sexuality and issues in contraception.

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.

Adolescent↗
PubMed1991

Gender differences in a clinic-referred sample of attention-deficit-disordered children.

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.

Achievement↗
PubMed1991

Computed tomography, magnetic resonance imaging and positron emission tomography with [18F]fluorodeoxyglucose in multiple system atrophy and pure autonomic failure.

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.

Atrophy↗
PubMed1991

Internalizing and externalizing symptoms and attributional style in youth with diabetes.

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.

Adaptation, Psychological↗
PubMed1991

Central and peripheral effects of arecoline in patients with autonomic failure.

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.

Adrenocorticotropic Hormone↗
PubMed1991

Beta-receptor sensitivity in autonomic failure.

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.

Autonomic Nervous System Diseases↗
PubMed1989

HLA in autonomic failure.

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.

Autonomic Nervous System Diseases↗
PubMed1989

Patterns of plasma levels of catechols in neurogenic orthostatic hypotension.

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.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

Effects of methylphenidate on cardiovascular responses in attention deficit hyperactivity disordered adolescents.

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.

Adolescent↗
PubMed1989

Changes in blood pressure and plasma noradrenaline in short-term hypothyroidism.

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.

Adult↗