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Biomedical subjects

G Black

Publications and source records attributed to G Black.

14 recordsLinked to original sources
PubMed1996

Cardiopulmonary bypass leads to a preferential loss of activated platelets. A flow cytometric assay of platelet surface antigens.

OBJECTIVE: In a prospective study surface antigens associated with platelet activation, aggregation, and adhesion and the platelet volume were measured to investigate the mechanism of the platelet function defect of cardiopulmonary bypass (CPB). METHODS: Blood samples were obtained during cardiac surgery before and after heparinization, as well as during and following extracorporeal circulation. The expression of the platelet surface glycoproteins (GP) IIb-IIIa, Ib, 53, and the granule membrane protein (GMP) 140 were measured using flow cytometry in platelet-rich plasma (PRP) before and after in vitro stimulation with adenosine diphosphate. A full blood count including mean platelet volume (MPV) was taken. RESULTS: Heparinization resulted in a significant increase of GP 53 and GMP 140 and a significant decrease of GP Ib expression. During and following CPB, GP IIb-IIIa and Ib were significantly decreased. Similarly, the expression of the activation markers was reduced significantly. The mean platelet volume decreased significantly from 8.6 +/- 0.7 fl at baseline to 7.9 +/- 0.8 fl at the end of the study period. CONCLUSION: Our data suggest that heparinization induces platelet activation. We assume that a loss of larger and more activated platelets from the circulation contributes substantially to the platelet function defect of CPB.

Adult↗
PubMed1996

Aprotinin has no effect on platelet activation and adhesion during cardiopulmonary bypass.

Aprotinin reduces blood loss following cardiopulmonary bypass operations (CPB) by the prevention of hyperfibrinolysis. Its influence on circulating platelets is uncertain. In this prospective trial we investigated activation, adhesion, and aggregation receptors on the platelet surface in 20 patients who underwent elective coronary artery bypass grafting. These patients were randomly assigned to receive either a high dose of aprotinin or placebo. Flow cytometry was performed to determine platelet activation [P-selectin, glycoprotein (GP) 53], adhesive (GP Ib), and aggregatory (GP IIb-IIIa) receptors on circulating platelets, before, during, and after CPB. Aprotinin had neither a significant effect on platelet activation nor on adhesive and aggregatory receptors. Plasma levels of D-dimers were measured before and after CPB to assess fibrinolytic activity. D-dimers following CPB and chest tube drainage were significantly less in the aprotinin group. We conclude that aprotinin reduces blood loss by its effect on fibrinolysis but has no direct influence on platelet function.

Adult↗
PubMed1995

Male neonatal death and progressive weakness and immune deficiency in females: an unknown X linked condition.

We report a family with an undiagnosed X linked condition. The grandmother, two of her three daughters, and one of her grand-daughters have a slowly progressive proximal weakness, brisk reflexes, poor bladder function, static reduced night vision, and IgG2 deficiency. The diagnosis of the three living symptomatic females was "hereditary spastic paraplegia plus". They have lost five male children who died in the neonatal period of severe hypotonia and were of low birth weight. Investigations have not led to a unifying diagnosis: myotonic dystrophy, NARP, and X linked hyper IgM were specifically eliminated. Using the hypothesis that the condition is X linked dominant, haplotype analysis of the family suggests that the disease locus is within Xq26-qter. This entity should be considered in the differential diagnosis of families presenting with severe neonatal hypotonia in males and females with symptoms suggestive of complex hereditary spastic paraplegia.

Adolescent↗
PubMed1994

The molecular biology of Norrie's disease.

The Norrie's disease gene has been accurately located on the short arm of the X chromosome. The methodology underlying this achievement and the structure of the three-exon gene is described in this review article. The clinical implications of these recent advances are discussed. Allelic variants of Norrie's disease and the phenomenon of females affected by X-linked disease are also discussed.

Chromosome Deletion↗
PubMed1993

Maternal and child health services in the Baltimore City Health Department, 1900-1992.

Maternal and Child Health Services in the Baltimore City Health Department, founded in 1934 and 1919, respectively, grew out of concern for maternal and infant death. Increasingly, services have focused on prevention and on building individual health by strengthening the family. The authors identify changing patterns of health care and the health department's continuing role in assuring high quality care and developing guidelines for cost-effective management.

Adult↗
PubMed1991

Health care use among young children in day care. Results in a randomized trial of early intervention.

Exposure of young children to group day-care settings increases the risk of illness and may result in higher use of medical care. These observations raise concerns that the use of such settings for early intervention programs for low-birth-weight infants may increase the already high burden of medical care costs incurred by these children and their families. To address the question of medical care use associated with center-based care, we examined the hospital-based and ambulatory care reported for participants of the Infant Health and Development Program. This project is a multisite randomized trial of an early intervention program for preterm low-birth-weight infants with an intervention including 2 years of center-based care. The Intervention group did not differ in hospital-based care and averaged only two more physicians' visits over the 3-year observation period than the comparison group. We conclude that early intervention programs involving high-quality group care are not accompanied by substantial increases in health care use.

Ambulatory Care↗
PubMed1985

Lack of photoprotection against UVB-induced erythema by immediate pigmentation induced by 382 nm radiation.

Immediate pigment darkening (IPD) was induced on the backs of 11 human volunteers of skin types III and IV by exposing the skin to UVA radiation (382 nm). The minimum erythema dose (MED) of UVB radiation was also determined by exposing sites to graduated doses of 304 nm radiation. The order of exposure of distinct anatomic areas was as follow: UVB followed by IPD induction; IPD induction followed by UVB; IPD induction followed 3 h later by UVB; and UVB only. Erythema responses induced by UVB were graded by inspection 24 h later and the MEDs in the 4 areas were compared. The induction of IPD before UVB exposure caused no significant change in the MED compared to sites receiving UVB only, or receiving UVA radiation after UVB, confirming that the IPD reaction does not protect against UVB-induced erythema. There was also no evidence of photorecovery, i.e., an increase in the MED of UVB resulting from exposure to longer wavelength, UV or visible radiation following UVB exposure.

Adolescent↗
PubMedDate not supplied

Social dominance and 22-year all-cause mortality in men.

OBJECTIVE: Research findings suggest that, in addition to hostility, social dominance-related variables may be related to morbidity and mortality. The purposes of the present study were to evaluate a) whether pressured social dominance (defined as a pattern of structured-interview-defined characteristics of verbal competition, immediateness of response, and fast speaking rate) was related to long-term health outcomes, namely, all-cause mortality, and b) whether individuals characterized by other patterns of structured-interview-derived characteristics also varied in terms of mortality. METHOD: The present study represents an analysis of the data from the 22-year mortality follow-up of 750 men from the Western Collaborative Group Study. Cluster analytic techniques were used to classify individuals according to their speech and behavioral characteristics during a structured interview. Cox proportional hazards models were used to test the association between the behavioral characteristics and the risk of all-cause mortality. RESULTS: The pattern of characteristics reflecting pressured social dominance was found to be positively related to mortality (RR = 1.6, 95% CI = 1.1-2.4, p < .02); this relation held after controlling for diastolic blood pressure, total cholesterol, and smoking status at study entry, and also after controlling for hostility. In addition, the pattern of characteristics in which hostility was salient was found to be positively related to mortality (RR = 1.5, 95% CI = 1.1-2.2, p < .02). Finally, a pattern of characteristics that suggests placid individuals who are neither hostile nor socially dominant was found to be significantly negatively related to mortality (RR = .638, 95% CI = .419-.974, p < .04). CONCLUSIONS: These results suggest that, in future research concerning psychosocial factors and long-term survival, attention should be given to social dominance as well as to hostility.

Adult↗