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Biomedical subjects

R L Young

Publications and source records attributed to R L Young.

At least 37 records · Page 2Linked to original sources
PubMed1995

The abilities of a musical savant and his family.

The ability of a male autistic savant (TR) to play two unfamiliar piano pieces after listening to a tape-recording was tested, closely following the procedures of Sloboda, Hermelin, and O'Connor (1985). Other components of TR's musical ability--pitch recognition, improvisation, and ability to provide harmonic accompaniment--were also examined. TR's musical precocity was examined in relation to his general level of intellectual functioning as indexed by a battery of standardized psychological tests of intelligence, memory, reading, visual organization, and creativity. His parents and two male siblings also completed tests of intelligence. Results from psychometric testing indicated that TR has idiosyncratic levels of cognitive functioning with difficulties in verbal reasoning but high levels of concentration and memory. His speed of information processing, as indicated by Inspection Time, and was better than average. TR demonstrated perfect pitch recognition and other family members also demonstrated excellent relative pitch. TR's ability to recall and perform structured music within both the diatonic and whole-tone systems was exceptional but dependent upon his familiarity with musical structure and was therefore organized and rule-driven. Furthermore, TR demonstrated competence in improvisation and composition, albeit restricted by his adherence to structural representations of familiar musical rules.

Aptitude↗
PubMed1994

The "intelligence" of calendrical calculators.

Strategies of 4 men (WAIS-R range 65 to 76) when making calendar calculations were investigated. Each subject completed a battery of standardized psychological tests. Results suggested that subjects were aware of rules and regularities associated with the calendar, including knowledge of the 14 different calendar templates, one of which describes any calendar year. Their strategies were rigidly applied and could not be modified easily, even when doing so would have facilitated performance. The involvement of practice, memory, anchor dates, eidetic imagery, and mathematical algorithms were discussed. We concluded that these savants relied heavily on memory, with little manipulation of cognitive input, as opposed to transforming stimuli.

Adult↗
PubMed1993

Calcitonin gene-related peptide mediates capsaicin-induced neuroendocrine responses in rat antrum.

BACKGROUND: Calcitonin gene-related peptide (CGRP) is a 37-amino acid peptide localized to primary sensory afferent nerves in the rat stomach. The actions of CGRP in regulating antral neuroendocrine function were examined in vitro through the use of capsaicin, an agent capable of evoking neuropeptide release from peripheral sensory nerve endings. These results were compared with the effects of exogenous CGRP and CGRP antagonist, CGRP8-37. METHODS: Rat antral mucosal/submucosal fragments were incubated in either static or dynamic perifusion experiments. Media were assayed for gastrin, somatostatin, CGRP, and acetylcholine. RESULTS: Capsaicin, like exogenous CGRP, stimulated antral somatostatin release and inhibited both gastrin release and acetylcholine discharge. Low dose capsaicin (1 x 10(-5) mol/L) caused significant stimulation of CGRP release: 33 +/- 0.2 vs. 14 +/- 1 pg/mL protein; P < 0.001. Tetrodotoxin blocked capsaicin-induced inhibition of acetylcholine release and prevented partially capsaicin-mediated stimulation of CGRP release. The CGRP receptor antagonist CGRP8-37 prevented capsaicin-induced D-cell stimulation and inhibition of G-cell secretion and cholinergic discharge. CONCLUSIONS: The effects of capsaicin-induced changes in antral D- and G-cell secretion and acetylcholine discharge are due primarily to release of CGRP. Antral CGRP release from primary sensory afferent nerve terminals may act as a local effector substance to regulate antral neuroendocrine function.

Acetylcholine↗
PubMed1993

Influence of alpha 1- and alpha 2-adrenoceptor antagonist therapy on the development of hypertension in spontaneously hypertensive rats.

There is general agreement that the sympathetic nervous system is involved in the development of hypertension in spontaneously hypertensive rats (SHR). However, in a previous study we established that chronic administration of the selective alpha 1-adrenoceptor antagonist terazosin to SHR failed to prevent this phenomenon. In the present study, we extended that investigation further by examining the effects of another selective alpha 1-antagonist (doxazosin), an alpha 2-adrenoceptor antagonist (yohimbine), and a combination of these agents. Chronic administration of doxazosin and yohimbine produced receptor blockade, as determined by their effect on blood pressure (BP) responses to norepinephrine (NE) and phenylephrine. Chronic administration of either antagonist alone or the two in combination failed to prevent the development of hypertension in SHR, however. These findings suggest that although there may be a need for involvement of the sympathetic nervous system in the development of hypertension in SHR, its influence on this process is not mediated through activation of alpha-adrenoceptors.

Adrenergic alpha-Antagonists↗
PubMed1993

A negative regulatory element in the bcl-2 5'-untranslated region inhibits expression from an upstream promoter.

bcl-2 mRNA is present at high levels in pre-B-cell lines but is down-regulated in most mature B-cell lines. To investigate the mechanisms responsible for its developmental control, we studied the regulation of bcl-2 expression in human B-lineage cell lines. Using nuclear run-on assays, we found that bcl-2 transcription decreases in parallel with levels of steady-state mRNA during B-cell development. To define cis-acting elements that regulate bcl-2 transcription, we analyzed the expression of transiently transfected promoter-reporter constructs. We identified a novel negative regulatory element (NRE) in the bcl-2 5'-untranslated region that decreased expression from the bcl-2 P1 promoter or heterologous promoters in a position-dependent fashion. The NRE functions in either orientation but contains distinct orientation-dependent subfragments. Additional analyses demonstrated that multiple, functionally redundant sequence elements mediate NRE activity. Though the bcl-2 NRE is active in pre-B- and mature B-cell lines, chromatin structure of the endogenous NRE differs in these cells, suggesting that its activity or effect may vary during B-cell development. Our results indicate that negative control of transcription initiated at the P1 promoter is an important determinant of the differential expression of bcl-2.

B-Lymphocytes↗
PubMed1992

A randomized, double-blind, placebo-controlled comparison of the impact of low-dose and triphasic oral contraceptives on follicular development.

OBJECTIVE: This investigation tests the hypothesis that triphasic oral contraceptives are associated with the development of large, persistent ovarian cysts. STUDY DESIGN: Weekly vaginal ultrasonography was used in a randomized, double-blind, placebo-controlled, parallel-group, single-center study that compared the incidence, risk, size, and time to resolution of ovarian follicles in healthy women who took Estrostep or Loestrin oral contraceptives (manufactured by Parke-Davis) or a placebo during three consecutive menstrual cycles. RESULTS: Sixty-three percent of placebo-treated subjects developed follicles greater than 18 mm, compared with 39% and 23% in the Estrostep and Loestrin groups. The risks for each group of developing a large follicle during a single cycle were not different. No dominant follicle persisted for greater than 2 weeks for any subject. CONCLUSION: These results demonstrate that follicular development continues during treatment with oral contraceptives. In addition, the findings fail to support the hypothesis that triphasic oral contraceptives result in persistent ovarian cysts.

Adult↗
PubMed1992

Cholelithiasis in patients treated with a very-low-calorie diet.

One hundred seventy-nine obese patients (mean body mass index = 36.3) were retrospectively evaluated for the development of cholelithiasis associated with the use of a 2530-kJ/d (605-kcal) very-low-calorie diet (VLCD). Nine percent of patients had preexisting gallstones and 11% of patients developed gallstones either during or within 6 mo of completing the diet. Six percent had subsequent cholecystectomy. Ursodeoxycholic acid administered to one patient resulted in spontaneous stone dissolution whereas spontaneous dissolution occurred in three patients. Surveys of patients at three other programs using the same diet yielded similar incidence of gallstones. We conclude that rapid weight loss associated with the use of VLCD is associated with a significant incidence of gallstone formation. VLCD should be physician supervised because resolution of cholelithiasis spontaneously, with stone passage, or dissolution with ursodeoxycholic acid therapy may reduce the need for cholecystectomy.

Cholecystectomy↗
PubMed1992

Atresia coli in the foal: a review of six cases.

Physical examination and exploratory celiotomy were performed on five neonatal foals presented with signs of acute colic. Atresia coli was confirmed in each foal during surgery. The most consistent finding on physical examination was the absence of meconium staining following repeated enemas. The large, transverse and/or small colon were involved in all foals. One eight month aborted foetus was submitted for necropsy and diagnosed as having atresia coli and congenital hydrocephalus. Atresia coli should be considered for neonatal foals with signs of acute colic.

Animals↗
PubMed1992

Calcitonin gene-related peptide: mechanisms of modulation of antral endocrine cells and cholinergic neurons.

Actions of human calcitonin-gene related peptide (hCGRP) on acetylcholine (ACh) discharge and gastrin and somatostatin release from rat antral mucosal-submucosal fragments were examined in both dynamic perifusion experiments and short-term static incubation studies. The principal findings of the dynamic perifusion experiments were that hCGRP exerted a dual or biphasic effect on ACh discharge and gastrin release. Initial exposure of antral tissues to hCGRP (1 x 10(-8) M) resulted in stimulation of both ACh and gastrin release that was of brief duration. Continued hCGRP perifusion caused subsequent inhibition of ACh and gastrin release that was substantially greater in duration and magnitude than the initial stimulatory responses. Static incubation studies indicated that hCGRP (10(-10) to 10(-7) M) stimulated somatostatin and inhibited gastrin release in a dose-dependent manner. Inhibition of gastrin and ACh release by hCGRP appeared to be an indirect effect that was mediated by somatostatin as suggested by studies with pertussis toxin (200 ng/ml). Furthermore, studies with atropine (1 x 10(-6) M) and tetrodotoxin (1 x 10(-6) M) indicated that CGRP-induced stimulation of somatostatin release and inhibition of ACh discharge occurred independent of muscarinic receptor activation and nerve excitation. In conclusion, results of these studies indicate that CGRP is capable of exerting both stimulatory and inhibitory effects on ACh release from mucosal-submucosal neurons and gastrin release from antral mucosal G cells in in vitro studies. These data suggest that the inhibitory effects of CGRP on cholinergic discharge and gastrin release are due to the paracrine effects of somatostatin released from antral D cells by direct action of CGRP.

Acetylcholine↗
PubMed1992

Selected aspects of polycystic ovarian disease.

Although there is general agreement about the polycystic ovary as an anatomic entity, a classic description of an associated syndrome remains elusive. This lack of definition, however, has not impeded clinical investigation. This article focuses on the diagnosis, pathogenesis, hypotheses, and treatment of polycystic ovarian disease.

Adrenal Cortex Hormones↗
PubMed1991

Estrogen replacement therapy is not conducive of venous thromboembolism.

Continued resistance to the use of hormone replacement therapy in menopausal women persists, in part because of concern over a possible relationship between estrogen use and venous thromboembolism. Numerous studies, both retro- and prospective, have failed to yield any evidence of increased relative risk for thrombosis: specific investigations have consistently failed to link estrogen use to clinically significant adverse changes in coagulation factors. We feel that any linkage of menopausal estrogen use and risk of venous thromboembolism is based on anecdotal comments and medical superstition.

Estrogen Replacement Therapy↗
PubMed1991

The use of an amniotic membrane graft to prevent postoperative adhesions.

Grafts of trypsin-treated, gamma-irradiated human amniotic membranes were used to cover injured uterine horns of nulliparous female rabbits to prevent adhesions. In this study, the gradual integration of the membranes into the serosal layer of the uterus, together with marked neovascularization, was observed. By the 30th postoperative day, the grafts had been completely integrated, with little evidence of rejection and no evidence of infection at the graft sites. Of 30 uterine horns treated with membrane grafts, only 4 (13.4%) showed any adhesion formation at or among the graft sites. All of the 24 untreated controls showed adhesion formation at the site of injury. Furthermore, whatever adhesions were found in membrane-treated horns could be graded as thin and filmy, accounting for less than 10% of the surface area of the graft, whereas the controls showed dense, thick adhesions covering 50% to 100% of the injured areas. We conclude that these specially prepared amniotic membranes are safe and effective in dramatically reducing postoperative adhesion formation in this animal model.

Animals↗
PubMed1991

Comparison of the long-term effects of estrogen and clomiphene citrate on pituitary and uterine function in ovariectomized rats.

The effects of estradiol-17 beta (E2) and clomiphene citrate (CC) on pituitary-uterine function in ovariectomized (OVX) rats were compared in two experiments. In experiment 1, CC completely blocked E2 stimulation of uterine weight when administered concurrently for 10 and 30 days. In experiment 2, content of total (occupied and unoccupied) uterine nuclear estrogen receptors was increased by E2, but not by CC, compared to OVX controls. Only a fraction of the nuclear receptors was occupied in E2-treated rats, whereas all of these receptor sites were occupied in CC-treated rats. In addition, uterine cytoplasmic estrogen receptors were increased by E2 and diminished by CC treatment. Both E2 and CC were effective in preventing the postovariectomy rise in serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH), although LH was always inhibited to a greater extent than FSH. After 30 days of treatment, pituitary gonadotropins were also substantially reduced by E2 and CC, suggesting that long-term treatment decreased both pituitary synthesis and release. An increase in pituitary weight observed in E2-treated rats only was due largely to the stimulation of lactotropes, as serum prolactin was increased. In summary, although CC and E2 similarly depressed pituitary gonadotropin secretion, they exhibited marked differences in the stimulation and occupancy of uterine estrogen receptors and the stimulation of pituitary prolactin secretion.

Animals↗
PubMed1990

Assessing skills for refusing cigarettes and smokeless tobacco.

Hops and colleagues developed an audiotaped refusals skills test in which students respond to cigarette offers and their responses are scored for content. The present study employed a modified analogue skills test. Modifications included adding a separate subscale for smokeless tobacco, emphasizing repeated offers and group pressure, and rating the quality of responses (good, fair, poor). The test was evaluated in four seventh-grade classrooms (N = 78). Half had participated in a refusals skills training program; the others were controls. Intervention subjects provided more "good" responses and fewer "poor" responses than controls. In a multiple regression, repeated and group offers were associated with the quality of response, while offerer's gender and type of tobacco variables were not associated. In a second regression, experimental condition was associated with quality of the responses, while gender, ethnicity, exposure to tobacco, use of tobacco, and attitudes toward the test were not associated.

Assertiveness↗