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Biomedical subjects

A Bang

Publications and source records attributed to A Bang.

13 recordsLinked to original sources
PubMed2000

Isohemoglobin differentiation in the bimodal-breathing amazon catfish Hoplosternum littorale.

The bimodal gill(water)/gut(air)-breathing Amazonian catfish Hoplosternum littorale that frequents hypoxic habitats uses "mammalian" 2,3-diphosphoglycerate (DPG) in addition to "piscine" ATP and GTP as erythrocytic O(2) affinity modulators. Its electrophoretically distinct anodic and cathodic hemoglobins (Hb(An) and Hb(Ca)) were isolated for functional and molecular characterization. In contrast to Hb(An), phosphate-free Hb(Ca) exhibits a pronounced reverse Bohr effect (increased O(2) affinity with decreasing pH) that is obliterated by ATP, and opposite pH dependences of K(T) (O(2) association constant of low affinity, tense state) and the overall heat of oxygenation. Dose-response curves indicate small chloride effects and pronounced and differentiated phosphate effects, DPG < ATP < GTP < IHP. Hb(Ca)-O(2) equilibria analyzed in terms of the Monod-Wyman-Changeux model show that small T state bond energy differences underlie the differentiated phosphate effects. Synthetic peptides, corresponding to N-terminal fragment of the cytoplasmic domain of trout band 3 protein, undergo oxygenation-linked binding to Hb(Ca), suggesting a metabolic regulatory role for this hemoglobin. The amino acid sequences for the alpha and beta chains of Hb(Ca) obtained by Edman degradation and cDNA sequencing show unusual substitutions at the phosphate-binding site that are discussed in terms of its reverse Bohr effect and anion sensitivities.

2,3-Diphosphoglycerate↗
PubMed1999

Giant eyes in Xenopus laevis by overexpression of XOptx2.

Overexpression of XOptx2, a homeodomain-containing transcription factor expressed in the Xenopus embryonic eye field, results in a dramatic increase in eye size. An XOptx2-Engrailed repressor gives a similar phenotype, while an XOptx2-VP16 activator reduces eye size. XOptx2 stimulates bromodeoxyuridine incorporation, and XOptx2-induced eye enlargement is dependent on cellular proliferation. Moreover, retinoblasts transfected with XOptx2 produce clones of cells approximately twice as large as control clones. Pax6, which does not increase eye size alone, acts synergistically with XOptx2. Our results suggest that XOptx2, in combination with other genes expressed in the eye field, is crucially involved in the proliferative state of retinoblasts and thereby the size of the eye.

Albinism↗
PubMed1996

Recipient humoral immunity against leukoreduced allogeneic platelets is suppressed by aminoguanidine, a selective inhibitor of inducible nitric oxide synthase.

Leukoreduced allogeneic platelet transfusions have been previously shown to initially stimulate an in vitro cellular cytotoxicity and subsequently Induce the formation of immunoglobulin G (IgG) antidonor alloantibodies. To further characterize these responses and determine if they are related, recipient BALB/c H-2d mice were treated with aminoguanidine (AMG), a selective inhibitor of inducible nitric oxide synthase (iNOS), and transfused weekly with 2 x 10(8) C57BL/6 H2b platelets. In control, non-AMG-treated mice, transfusion significantly (P < .01) increased serum levels of interferon-gamma (IFN-gamma) by day 1 posttransfusion (PT). IFN-gamma returned to pretransfusion levels by day 3 PT, and its production was not affected by AMG treatment. Serum interleukin-4 (IL-4), on the other hand, was undetectable before and during the transfusion protocol. By day 3 PT, recipient spleen cells could mediate in vitro anti-P815 (auto), anti-EL4 (allo), and anti-R1.1 (third-party MHC) cytotoxicity, and these responses were maximal by day 7 PT. Concurrently, a significant reduction in the vitro ability of recipient splenocytes to respond to Concanavalin A (ConA) was observed; this was not seen with lipopolysaccharide (LPS) stimulation. Elevated levels of NO2- were found in the ConA culture supernatants from transfused mice at day 3 PT. Serum antidonor alloantibodies were detected by the fifth platelet transfusion. AMG treatment of recipient mice significantly inhibited the transfusion. Induced cytotoxicity and ConA-stimulated NO2- production, and restored ConA-induced proliferation to normal levels. AMG appeared to selectively inhibit platelet-induced alloantibody production in that it did not affect antibody production induced by transfusions with 10(5) allogeneic leukocytes or by immunization with a foreign protein antigen, human gamma globulin, in adjuvant therapy. These results indicate that an in vivo AMG-sensitive mechanism is essential for recipients to initiate a humoral IgG immune response against allogeneic platelets.

Animals↗
PubMed1989

Commentary on a community-based approach to reproductive health care. Society for Education, Action and Research in Community Health Team.

Reproductive care needs to be broadened beyond maternity care and family planning to include care for gynecological and sexual problems, safe abortion services, and sex and reproductive health education. Our epidemiologic study of rural women has shown a very high prevalence of gynecological diseases. We tried to develop a community-based approach to comprehensive reproductive care by undertaking participatory research, fostering mass education with the people's involvement, and by making care available through village-based female workers and improved referral services. We end with two appeals: "MCH" needs to be replaced by WCH: not merely Maternal and Child Health but Woman and Child Health. Care should be provided through a community-based participatory approach, not through narrow technocratic vertical programs. Let people shape their own lives!

Abortion, Illegal↗
PubMed1984

Acute care hospitals providing elderly and long-term care services: a survey of the Massachusetts experience.

To assess the involvement of hospitals in geriatric, community and long-term care services, a survey was undertaken of the 104 acute care hospitals in Massachusetts. Results show that hospitals (N = 81) are adding geriatric expertise but as yet have taken on community services and long-term care only to a small extent. Hospitals perceive major deficiencies in physician service to nursing homes (89 per cent) and in availability of inpatient geriatric units (94 per cent). Responding hospitals have targeted for development by 1985 geriatric inpatient units (17 per cent), respite care (16 per cent), and hospice care (16 per cent). The financial implications of the survey results are discussed with respect to prospective reimbursement and public health implications.

Aged↗