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Biomedical subjects

J H Carter

Publications and source records attributed to J H Carter.

At least 73 records · Page 4Linked to original sources
PubMed1988

Adrenal regulation of mammary tumorigenesis in female Sprague-Dawley rats: histopathology of mammary tumors.

Mammary tumors induced in female Sprague-Dawley rats by feeding 7,12-dimethylbenz(a)anthracene (DMBA; 20 mg/100 g body weight) were classified according to histological criteria of tissue differentiation, cellular atypia, and evidence of invasion. The 549 tumors could be placed in three categories, nodular hyperplasia, nodular hyperplasia with atypia, and carcinoma, and combinations of all three. Although tumors classified histologically as carcinomas did not metastasize, upon transplantation to the kidney capsule, a tumor classified as a carcinoma grew for eight generations and metastasized. Tumor heterogeneity was a common finding in DMBA-initiated tumors. Carcinomas were an early lesion. As the length of time between DMBA treatment and sacrifice increased, more tumors with areas of carcinoma were found. Therefore, DMBA-initiated tumors progressed to carcinomas either soon after initiation or later by development within nodular hyperplasias. In 4 separate groups of animals (74 adrenalectomized rats and 90 intact rats), postinitiation adrenalectomy increased the numbers of carcinomas compared to intact animals. This effect was consistently seen in the cervical and thoracic mammary glands. We propose that the mechanism for enhancement of progression to greater malignancy by adrenalectomy may be inhibition of differentiation of initiated cells in the absence of glucocorticoids.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1988

Duodenal and gastric delivery of levodopa in parkinsonism.

To clarify the influence of gastric emptying on levodopa-related motor fluctuations in Parkinson's disease, we assessed mobility and plasma levodopa concentrations in 10 patients during five modes of levodopa administration: (1) standard intermittent oral (SIO), (2) intermittent duodenal (ID), (3) continuous duodenal infusion (CDI), (4) continuous gastric infusion (CGI), and (5) controlled-release Sinemet (CR-4). The rank order from greatest to least for both percentage of time "on" and average mobility score was CDI, CGI, ID, CR-4, and SIO. The rank order for variance of means, a measure of fluctuation, from least to greatest for mobility was CDI, CGI, CR-4, ID, SIO, and for plasma levodopa concentrations was CDI, CGI, ID, SIO, and CR-4. The results demonstrate that it is possible to produce very steady plasma concentrations of levodopa with a corresponding reduction in motor fluctuations by continuous intraduodenal administration of the drug. This mode of delivery is an ideal model for the development of optimal continuous-release preparations of levodopa. Other enteral routes have produced a more variable plasma levodopa concentration and clinical response.

Administration, Oral↗
PubMed1988

Quantitative and qualitative immunohistochemical detection of myc and src oncogene proteins in normal, nodule, and neoplastic rat liver.

This study examined the possibility of using an immunohistochemical technique to detect the expression of myc and src oncogene proteins (ops) in livers of male Sprague-Dawley rats after treatment with the carcinogen diethylnitrosamine (with or without phenobarbital promotion) or untreated. We found that the majority of nodules and tumors from these livers stained for myc and src ops, indicating that myc and src expression did occur in these structures. These results were expected, since myc and src expression has been previously observed by others using different techniques. However, in our study, myc and src op staining was also noted in normal liver areas from rats in any of the four treatment groups (DENA, DENA + PB, PB alone, or untreated). The staining pattern of normal liver was different for each oncogene probe but was consistent within the four groups. In most cases, oncogene expression of normal liver occurred at sites of abnormal (but non-neoplastic) hepatocytes. The method reported here used both a qualitative technique of op expression analysis and a quantitative method using a Zeiss computer-driven image analysis system.

Animals↗
PubMed1988

Treating the black female alcoholic: clinical observations of black therapists.

Empirical observations from a decade of treating economically deprived black female alcoholics at the Lincoln Community Health Center in Durham, North Carolina, indicate that recognition of the social and cultural determinants of alcoholism is crucial to treatment. Scrutiny of the approach suggests that the psychopathology of these patients was inextricably intertwined with issues of racism, unemployment, poverty, and substandard housing. It is concluded that a comprehensive health care approach that utilizes the input of a black female therapist as the case manager has distinct advantages.

Black or African American↗
PubMed1986

A system of retinoscopy for the aged eye.

A method of retinoscopy is described in which an optical arrangement magnifies the patient's pupil and makes it easier to see the retinoscopic reflex. At the same time, the method permits retinoscopic observation by the emmetropic examiner without need for accommodation, a distinct advantage to the presbyopic examiner. The relationship between retinoscope position and dioptric power-error is linear, a feature that facilitates cylinder determination using a variable-distance technique.

Accommodation, Ocular↗
PubMed1986

Clinical and biochemical studies with controlled-release levodopa/carbidopa.

In five patients with parkinsonism, the optimal dosage of a controlled-release levodopa/carbidopa preparation (CR-3) was three times higher than the dosage of Sinemet and produced higher plasma levodopa concentrations, but did not reduce the fluctuations in plasma levodopa or clinical response. Plasma levodopa concentrations were higher and clinical responses better before the first dose of the day with CR-3. CR-3 treatment benefited two patients, reducing the severity of off periods and off dystonia. Two patients were worse on CR-3 despite higher plasma levodopa levels than those adequate for clinical response to Sinemet or levodopa infusions. CR-3 could benefit a few severely affected patients, but it is necessary to understand the factors that affect absorption of levodopa from sustained-release preparations, as well as the consequences of prolonged elevation of plasma levodopa levels.

Aged↗
PubMed1986

Suicide and black adolescents: a medical dilemma.

The psychosocial dynamics of black adolescent suicide are examined in light of the available literature and the authors' clinical experience. The authors contend that members of the medical profession who are in touch with the physical problems of black adolescents must become sensitive to the magnitude of the problem and assist with developing compassionate, bold, and responsible suicide prevention and treatment modalities.

Black or African American↗
PubMed1986

Treatment considerations with black incestuous families.

This paper is concerned with father-daughter incest among blacks and the cultural and legal issues that tend to perpetuate incestuous behavior. From a decade of observations, the authors describe findings about the psychosocial and behavioral sequelae of this phenomenon in black families.

Adolescent↗
PubMed1985

Novel rhodamine tripeptide substrate for manual and automated colorimetric prothrombin time test.

A chromogenic prothrombin time test is described using the tripeptide substrate, (Sar-Pro-Arg)2-Rhodamine 110. The method is both precise and sensitive to the factors of the extrinsic pathway. The accuracy of the method was demonstrated by comparison of patient sample values to standard clotting test results. The manual substrate test was adapted to two different automated chemistry analyzers.

Autoanalysis↗
PubMed1985

Lisuride treatment of focal dystonias.

Nine patients with various focal dystonias participated in a 12-week, double-blind, crossover comparison of the dopamine agonist, lisuride, and placebo. Lisuride produced mild objective and subjective improvement in six subjects, but the improvement was not sustained with continued therapy. Because the patients generally identified the active drug by side effects, biasing the study toward finding an effect, and because the benefits were mild and transient, we conclude that lisuride is of limited use in the treatment of focal dystonias.

Adult↗
PubMed1984

The "on-off" phenomenon in Parkinson's disease. Relation to levodopa absorption and transport.

To determine whether the oscillating clinical response to levodopa in Parkinson's disease (the "on-off" phenomenon) reflects fluctuations in absorption and transport of the drug, we investigated this phenomenon in nine patients with an oscillating motor state. We studied the response to continuous infusion of levodopa and the effects of meals on the plasma levodopa concentrations and on the clinical response during oral and intravenous administration of the drug. Meals reduced peak plasma levodopa concentrations by 29 per cent and delayed absorption by 34 minutes. Bypassing absorption by constant infusion of the drug produced a stable clinical state lasting for 12 hours in all of six patients and for up to 36 hours in some. High-protein meals or oral phenylalanine, leucine, or isoleucine (100 mg per kilogram of body weight) reversed the therapeutic effect of infused levodopa without reducing plasma levodopa concentrations. Glycine and lysine at identical doses had no effect. We conclude that interference with absorption of levodopa by food and by competition between large neutral amino acids and levodopa for transport from plasma to the brain may be partly responsible for the fluctuating clinical response in patients with Parkinson's disease.

Administration, Oral↗