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Biomedical subjects

L M Greenberg

Publications and source records attributed to L M Greenberg.

At least 19 recordsLinked to original sources
PubMed1996

Estrogen absorption and metabolism in postmenopausal women with end-stage renal disease.

Women with end-stage renal disease (ESRD) have a higher rate of death from heart disease than women with normal renal function. Because estrogen replacement therapy may significantly decrease the incidence of death due to cardiovascular disease in postmenopausal women with normal renal function, their use has been considered for women with ESRD. However, the pharmacokinetics of estrogen have not been studied in postmenopausal women with ESRD to determine the optimal estrogen dose. Six postmenopausal women with ESRD receiving maintenance hemodialysis and six controls matched for body mass index were admitted to the in-patient Clinical Research Center. A 1- or 2-mg oral estradiol (E2) pill was given while subjects fasted. Blood sampling was performed over the next 24 h for measurement of E2, estrone (E1), albumin, and sex hormone-binding globulin (SHBG). Three weeks later, the subjects were given the other E2 dose under identical conditions. At baseline, total and free E2 levels were higher in the subjects with ESRD than in controls (P = 0.0005 and 0.0035, respectively). After ingestion of 1 and 2 mg E2, total and free E2 levels remained significantly higher in the ESRD subjects from 2-8 h after treatment (P < or = 0.05). After 1 mg oral E2, total serum E2 peaked at 65 pg/mL at 4 h in ESRD subjects and at 27 pg/mL in control subjects at 8 h. After 2 mg oral E2 treatment, total serum E2 peaked at 8 h in both ESRD and control subjects, with levels of 99 and 37 pg/mL, respectively. E1 was higher in the subjects with ESRD than in the control subjects at baseline (P < 0.05). After ingestion of 1 mg E2, E1 concentrations were not significantly higher in ESRD than in control subjects, peaking at 180 and 121 pg/mL, respectively (P = 0.3). E1 concentrations were higher in ESRD than in control subjects after the ingestion of 2 mg E2, with peak levels of 376 and 201 pg/mL, respectively (P = 0.03). Total and free E2 levels are higher in patients with ESRD than in control subjects at baseline and after E2 ingestion, indicating that renal failure alters the pharmacokinetics of both endogenous and exogenous E2. Therefore, conventional E2 doses used in individuals with normal renal function may be excessive for patients with ESRD.

Absorption↗
PubMed1993

Developmental normative data on the test of variables of attention (T.O.V.A.).

Developmental normative data for 775 children aged 6-16 are presented for the Test of Variables of Attention (T.O.V.A.), a 23-minute fixed-interval visual Continuous Performance Test with minimal language demands and no left-right discrimination. The target is presented on 22.5% and 77.5% of the trials during the first and second halves, respectively, T.O.V.A. indices include omission and commission errors, response time means and standard deviations, and anticipatory responses. Attention and impulse control developed in a non-linear manner, changing rapidly in early childhood and leveling off during later childhood and adolescence.

Adolescent↗
PubMed1989

Hard-rock mining exposures affect smokers and nonsmokers differently. Results of a community prevalence study.

The physiologic consequences of occupational dust exposure, their relation to smoking, and their reversibility with cessation of exposure remain controversial. To address these questions, we studied a random sample of male residents of Leadville, Colorado when the major employer, a hard-rock mine, had been closed for 5 to 11 months. Subjects were interviewed for respiratory symptoms and occupational history, underwent plethysmographic measurements of lung volume and airflow, and performed a single breath diffusing capacity procedure. Dyspnea was the only respiratory symptom exacerbated by mining exposures. Cumulative dust exposure, estimated with historic respirable dust measurements for mining job titles and weighted by time at the job, was associated with decreases in maximal expiratory flow rates when controlled for smoking, age, and height. However, determinations of plethysmographic lung volume that allowed calculation of flow rates at equivalent absolute lung volume indicated that dust effects differed in never-smokers and smokers. In never-smokers, dust exposure was associated with decreased lung volume, increased flow rates, and increased DLCO/VA. In smokers, dust exposure was associated with increased lung volume, lower flow rates, and lower DLCO/VA than that accounted for by smoking. We suggest that hard-rock mining exposures result in irreversible pulmonary function changes of airflow limitation in smokers and of a restrictive nature in never-smokers.

Adult↗
PubMed1988

Pediatric upper airway obstruction due to ectopic thyroid: classification and case reports.

Few clinical situations can be as frightening, challenging, and as rewarding as stabilizing the airway of a child. Most causes of pediatric upper airway obstruction are well recognized, often discussed in the literature, and commonly encountered in practice. However, ectopic thyroid (i.e., thyroid tissue found in places other than its normal location) may be an unusual cause of pediatric upper airway obstruction with which the clinician may not be familiar. The resulting airway obstruction may be slow or rapid in onset, total or partial, and the relationship of the thyroid to the airway may be clear or obscure. Two cases of obstructing ectopic thyroid are presented which demonstrate the spectrum within which this form of airway obstruction may occur. One case is the first reported example in the English literature of pediatric intratracheal thyroid. A review of the literature is also presented. Four types of ectopic thyroid (lingual, sublingual, thyroglossal, and intralaryngotracheal) are illustrated and discussed in relation to their effect upon the pediatric upper airway. The authors also review the developmental anatomy of the thyroid and present two major theories regarding the development of intralaryngotracheal thyroid. The possible etiologies of the other ectopic forms are also discussed.

Airway Obstruction↗
PubMed1984

The effects of neuroleptics on attention in adolescent schizophrenics.

In contrast to studies of adult psychiatric patients, there was no striking difference between vigilance task performance by 11 newly diagnosed, previously untreated adolescent schizophrenics and that of 58 nonpsychotic adolescent comparison subjects. Neuroleptic treatment failed to improve the performance of the schizophrenic subjects. Sedation, a frequent side effect, was associated with significant prolongation of reaction time and an increase in error rate. Attentional characteristics of adolescent schizophrenics appear to resemble those of other disturbed children. Their response to neuroleptics appears to be limited and the deleterious effects of sedation on attention may well outweigh any clinical benefit attributable to sedation. Findings are discussed in terms of methodology and age-related characteristics.

Adolescent↗
PubMed1979

Epidemiologic characteristics of breast cancer in three menopausal stages: preliminary findings.

A preliminary analysis of data from 1,477 patients with breast cancer and 2,695 control women examined potential characteristics of high risk for breast cancer to determine whether prediction differed depending on whether the women were premenopausal, paramenopausal (intermediate), or postmenopausal. Since information was not yet available on real or presumed menopausal status, women were characterized by age: women less than 45 years as premenopausal; women from 45 through 54 years as paramenopausal; and women 55 years and older as postmenopausal. Height, weight at age 20, number of stillbirths, number of abortions, and history of cancer of any site in the subject's mother did not affect the risk of breast cancer. Generally, highest level of education, number of pregnancies, and number of live births seemed to predict risk of breast cancer. Weightbody mass index, age at menarche, and age at first pregnancy may predict breast cancer risk differently depending on the menopausal stage in which onset occurs.

Adult↗
PubMed1977

Self-conscious behavior of infants: a videotape study.

The reactions of 4 infants each at ages 10, 15, and 20 months were recorded on videotape as they responded to their own simultaneous video image, their own previously taped video image, the image of a control infant, and that of a female stranger. The subjects' responses were coded by 2 research assistants, ignorant of the original stimuli and the purpose of the study. The following behavioral categories were used: attends, sociable behavior, curiosity, unhappiness-withdrawal, and self-consciousness. The 1st-step discriminant according to a matrix algebra analysis between age groups was self-conscious behavior in response to the simultaneous video image. Twenty month-old infants were significantly different in their display of self-consciousness from the 10 and 15 month-old groups; the latter did not differ from each other.

Age Factors↗
PubMed1977

Agreement of mothers' and teachers' hyperactivity ratings with scores on drug-sensitive psychological tests.

Hyperactivity ratings were obtained from parents and teachers for 45 hyperactive, children. The children were also given several psychological tests. Teachers' ratings, but not parents' ratings were negatively correlated with performance on the psychological tests that require sustained attention and on which performance is improved by stimulant drugs. This pattern of correlations was interpreted as evidence that teachers, but not parents, have an opportunity to observe children performing daily tasks that require sustained attention.

Attention↗
PubMed1977

Serial neurologic examination of hyperactive children.

Forty-four of 102 children undergoing pharmacologic treatment of hyperactivity received serial neurologic examinations on five separate occasions. The responses to three of the "soft" neurologic signs administered were analyzed: heel gait, toe gait, and diadochokinesis. A high degree of variability of response within individuals was documented. There was no evidence of interaction between treatment and the subjects' responses. The degree of variability was such that to have used these data as measures of "improvement" (i.e., drug effect) would have been misleading. The value of these signs for purposes of diagnosis or assessment of therapy is doubtful.

Child↗
PubMed1975

Blood pressure and pulse changes in hyperactive children treated with imipramine and methylphenidate.

The authors found significant increases in systolic and diastolic blood pressure and pulse rate in hyperactive children treated with imipramine. Methylphenidate-treated children showed significant weight loss but no significant changes in blood pressure or pulse. The authors recommend caution in the use of imipramine and suggest the need for further study to determine short- and long-term effects of imipramine on blood pressure.

Adolescent↗