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Biomedical subjects

P Callahan

Publications and source records attributed to P Callahan.

32 records · Page 2Linked to original sources
PubMed1992

Cadmium exposure inhibits the prolactin secretory response to thyrotrophin releasing hormone (TRH) in vitro.

In vitro dose response (0.1-100 microM) and time course studies were performed on anterior pituitary cells isolated from female Sprague-Dawley rats in the diestrous stage of the estrous cycle. All doses of TRH produced a significant increase in prolactin release by 5 min which was sustained for 30 min. Pretreatment with 25 or 50 microM Cd for 2 or 4 h produced a significant decrease in prolactin secretion during Cd exposure and in the prolactin secretory response to 1 microM TRH. These results suggest that Cd pretreatment alters the subsequent ability of the lactotrophs to respond to the physiological secretagogue TRH. This alteration does not appear to be due to a rebound phenomenon since basal prolactin release was the same in Cd-pretreated and control cells once the metal was removed. These results suggest that Cd pretreatment produces a significant decrease in prolactin release from the anterior pituitary lactotrophs in response to subsequent TRH stimulation in vitro.

Animals↗
PubMed1990

Brief admission program. An alliance of inpatient care and outpatient case management.

1. Brief planned and crisis admissions to an inpatient psychiatric unit are presented as a component supportive of outpatient care and case management for chronically mentally ill patients. 2. Typical patients admitted to this inpatient short-term program are those experiencing a life stress or temporary crisis; chronically mentally ill patients who cycle and experience exacerbations of their illness; and those who need to make the transition from an acute inpatient unit to community living. 3. The Brief Admission Program treats the individual's response to and the consequences of a lifelong illness and enables the patient to return to his previous level of functioning and continue necessary outpatient treatment.

Activities of Daily Living↗
PubMed1988

Morphine does not stimulate prolactin release during lactation.

The ability of morphine to stimulate prolactin and growth hormone (GH) release was investigated in male rats and in female rats during diestrus, proestrus and lactation. In agreement with previous reports, acute morphine administration produced an increase in circulating levels of prolactin in male and in diestrous and proestrous female rats. In contrast to these results, morphine administration (10 or 15 mg/kg, s.c.; 5 mg/kg, i.v.; 5 or 10 micrograms, i.c.v.) did not produce an increase in prolactin levels in lactating dams. Morphine stimulates prolactin release in part by decreasing dopamine turnover in the tuberoinfundibular neurons in the median eminence. In order to assess the functional activity of these neurons during lactation, haloperidol (0.1 or 0.5 mg/kg, i.v.) was given to lactating dams. There was a significant increase in prolactin levels following haloperidol administration, suggesting that these dopaminergic neurons are participating in the modulation of prolactin release during lactation. In contrast to the insensitivity of the lactating rat to morphine stimulation of prolactin release, the intraventricular administration of two other opiate receptor agonists, beta-endorphin (10 or 20 micrograms) and [D-Ala-D-Leu]enkephalin (DADLE; 5 or 10 micrograms), produced significant increases in circulating levels of this hormone. The GH response to morphine, beta-endorphin and DADLE was also measured in these same rats. All these opiate receptor agonists stimulated GH release in male rats and in female rats during diestrus and proestrus as well as during lactation. These observations suggest that the suckling stimulus during lactation renders the rat refractory to morphine stimulation of prolactin release, possibly as a result of down-regulation of the mu-opiate receptor subtype.

Animals↗
PubMed1988

Time course of the insensitivity of prolactin release to morphine administration in the lactating female rat.

The effect of morphine on circulating levels of prolactin and growth hormone (GH) in the lactating female model was determined at various time intervals following the termination of suckling. Morphine administration did not produce an increase in prolactin levels when dams remained suckling. Four days after suckling was terminated, 50% of the dams tested showed a morphine induced prolactin increase. The prolactin secretory response to morphine gradually returned in dams, so that after 8 days of non-suckling, all animals tested showed a morphine induced prolactin increase. Consistent with the lack of prolactin stimulation, the tuberoinfundibular dopaminergic (TIDA) neurons, were insensitive to the morphine induced inhibition of activity during lactation. In contrast, circulating levels of GH were increased in these dams following morphine administration. These results suggest that the lactating female rat is insensitive to the mu mediated stimulation of prolactin release while suckling. However, sensitivity begins to return following at least 4 days of non-suckling.

Animals↗
PubMed1986

Prolactin release and tuberoinfundibular dopaminergic neuronal activity following single and double injections of morphine.

It is well established that opiate agonists alter tuberoinfundibular dopaminergic activity and consequently prolactin release. The purpose of this study was to characterize the effects of morphine on prolactin secretion and tuberoinfundibular dopaminergic neuronal activity with respect to time after administration. Additionally, the effect of an initial morphine injection on the response produced by a second injection of morphine was determined. The rate of depletion of median eminence dopamine content following synthesis inhibition by alpha-methyl-p-tyrosine was used as an index of dopaminergic neuronal activity. Male rats given a single injection of morphine sulfate (15 mg/kg, s.c.) showed a significant increase in circulating prolactin levels and had a lower rate of median eminence dopamine turnover 1 h after injection. Four hours after injection, circulating prolactin levels were similar to those in vehicle treated rats, while dopamine turnover was significantly higher than controls. When two injections of morphine sulfate (15 mg/kg, s.c.) were given 4 h apart, the stimulation of prolactin release produced by the second injection was significantly attenuated. Although this second injection caused a significant decrease in dopamine turnover, the turnover rate following this injection was significantly greater than that following the initial injection. The combination of fluoxetine and 5-hydroxytryptophan (FLX/5-HTP) caused an initial increase in prolactin secretion with plasma values returning to basal levels by 4 h. When rats were pretreated with FLX/5-HTP instead of morphine, the prolactin response to an injection of morphine 4 h later was not attenuated. Similarly a FLX/5-HTP pretreatment had no influence on a second injection of FLX/5-HTP administered 4 h later.(ABSTRACT TRUNCATED AT 250 WORDS)

5-Hydroxytryptophan↗
PubMed1986

A primary genetic map of chromosome 13q.

We have constructed a primary genetic map spanning most of human chromosome 13. A total of 14 polymorphic DNA sequences and one protein polymorphism provided, after construction of haplotypes, seven markers for the long arm of this chromosome. A panel of cell lines from 30 three-generation families with large sibship size served as the sample set. Pairwise cross analysis of the inheritance patterns of the marker loci established that six of the seven loci constituted a single linkage group; the seventh was localized by physical means. Significantly higher recombination rates were found in female than in male meioses in several intervals. The six closely linked loci were arranged, based on the two-point data, in three clusters, and a number of alternate gene orders were excluded by three-point linkage tests. The order and spacing of the individual loci were refined by linkage analyses that considered five loci jointly.

Chromosome Banding↗
PubMedDate not supplied

Primary care management of common dermatologic disorders in women. Pharmacologic considerations.

This article describes the clinical management of dermatologic disorders most commonly encountered in the primary care setting. The common presenting clinical signs and symptoms are reviewed, and the initial laboratory tests that may establish the diagnosis are recommended. Pharmacologic and nonpharmacologic treatments are reviewed. Diagnosis and management of disorders of the sebaceous and apocrine glands, disorders of the hair and pigmentation, fungal, viral, and bacterial infections, dermatitis, and infestations are discussed. A review of the care of skin burns and wounds is included as well as the diagnosis and management of urticaria.

Antiparasitic Agents↗
PubMedDate not supplied

Cervical pathology in West Virginia adolescents.

Cytologic screening is an important diagnostic tool used to detect precancerous and cancerous lesions of the cervix. We studied the prevalence of cervical abnormalities, based on Pap smear results, in patients at the Outpatient Adolescent Clinic at West Virginia University. We found a high incidence of overall intraepithelial cell pathology (24%) in this group with 2.4% high grade and 9.9% low-grade lesions. These findings show that major cervical pathology is present in this age group. Furthermore, repeat smears at intervals of < one year were performed on 317 patients. Of these repeat smears, 7% changed from normal to abnormal in this period. Sexually active adolescent females should have Pap smears at least annually to detect abnormalities that may otherwise not be detected until they are more advanced and difficult to manage. Higher risk adolescents may need semiannual screening.

Adolescent↗