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Biomedical subjects

T L Wright

Publications and source records attributed to T L Wright.

141 records · Page 8Linked to original sources
PubMed1983

Listeners' identification of human-imitated animal sounds.

To determine whether listeners can accurately identify human-imitated animal sounds, 20 speakers (10 females and 10 males) recorded their imitations of cows, cats, dogs, pigs, and sheep. These recordings were randomly arranged on a master tape and presented to 30 judges for identification. Analysis indicates that listeners can accurately identify various human-imitated animal sounds. Implications and suggestions for future research are discussed.

Adult↗
PubMed1983

Inhibition of erythroid colony formation by autologous bone marrow adherent cells from patients with the anemia of chronic disease.

To determine the role marrow-adherent cells may play in the anemia of chronic diseases, marrow samples were collected from ten patients with the anemia of chronic disease, seven control patients with cancer but without the anemia of chronic disease, and five normal volunteers. Marrow was either cultured directly or first depleted of adherent cells and then cultured. Plasma clots containing 6 X 10(4) nonadherent marrow cells were cocultured with marrow-adherent cells prepared by incubating 6 X 10(4)-6 X 10(2) unfractionated marrow cells in microtiter plates and removing the nonadherent cells. Adherent cell depletion of marrow from patients with anemia of chronic disease significantly increased erythroid colony formation. Coculture of adherent cells from anemic patients with autologous nonadherent marrow cells inhibited erythroid colony-forming unit (CFU-E) proliferation in patients with the anemia of chronic disease. In contrast, adherent cells from control patients did not affect autologous erythroid colony formation, and adherent cells from normal volunteers stimulated autologous erythroid colony formation. Coculture of adherent cells from anemia patients with nonadherent marrow from control patients failed to inhibit allogeneic erythroid colony formation. Media conditioned by adherent cells from patients with the anemia of chronic disease failed to suppress consistently the formation of allogeneic erythroid colonies. These data suggest that marrow-adherent cells normally stimulate erythropoiesis, but suppress erythroid progenitors, in patients with the anemia of chronic disease and may in part be responsible for their anemia.

Adolescent↗
PubMed1976

Radiation-induced cerebrovascular disease in children.

Radiation-induced internal carotid artery occlusion has not been well recognized previously as a cause of childhood cerebrovascular disease. A child who had received radiation as a neonate for a hemangioma involving the left orbit at the age of 6 years experienced a recurrent right-sided paresis, vascular headaches, and speech difficulties. Angiography showed a hypoplastic left carotid artery with occlusion of both the anterior and middle cerebral arteries. Collateral vessels bypassed the occluded-stenotic segments. Review of the literature showed two additional cases of large vessel occlusion in childhood associated with anastomatic telangiectatic vessel developmental following early radiation therapy of facial hemangioma.

Age Factors↗
PubMedDate not supplied

Interaction of natural and synthetic albumin polymers with hepatocytes.

The hepatitis B virus binds avidly to albumin polymers which in turn may mediate the initial binding of viral particles to the liver cell. However, the interaction of albumin polymers with the liver remains poorly characterized, and the possibility that hepatic binding reflects an artifact of polymerization with glutaraldehyde has not been excluded. We therefore characterized the binding of 125I-labeled natural and synthetic albumin polymers to suspensions of rat hepatocytes. Saturable binding was demonstrated for all preparations of monomeric and polymeric albumin studied. Glutaraldehyde-polymerized albumin (mean polymerization number = 15) bound much more avidly than naturally occurring albumin polymers (mostly dimers and trimers) or monomeric albumin. Competition between monomer and synthetic polymer was not observed. Reduction of free aldehyde groups on the synthetic polymer decreased nonsaturable binding without affecting saturable binding. Autoradiography confirmed binding of polyalbumin to hepatic parenchymal cells. Glutaraldehyde-polymerized ovalbumin, a protein unrelated to serum albumin, also bound hepatocytes saturably. We conclude that hepatic binding of synthetic albumin polymers is not due to residual aldehyde groups on the polymer and is much more avid than for natural polymer. This difference may reflect the higher degree of polymerization or chemical modification of the synthetic polymer. The hepatic binding sites for synthetic polymer appear distinct from those previously described for monomeric albumin and may not be specific for albumin.

Animals↗
PubMedDate not supplied

Hepatitis C and liver transplantation.

Hepatitis C virus (HCV) is important to the liver transplant recipient for several reasons. First, chronic HCV infection is a frequent cause of end-stage liver disease in North America and Europe, where the majority of liver transplants are performed. Second, recurrence of HCV after liver transplantation is almost universal so that many liver transplant recipients with and without overt hepatitis are viraemic. Third, HCV infection in the organ donor and/or in the blood transfused in the peri-transplant period make acquisition of HCV possible. Finally, liver transplantation for chronic HCV infection represents a major financial burden to the health-care system in the USA and worldwide. Histological hepatitis not due to HBV or cytomegalovirus (CMV) is present in 14-35% of allografts from patients undergoing liver transplantation, and the majority of this is due to HCV infection. HCV infection recurs post-transplant in almost all patients with pre-transplant infection. Proof that HCV does recur has been provided by the sequencing of the hypervariable domain of the E2/NS1 region. The magnitude of HCV infection is underestimated by using serological assays in this immunosuppressed population. Using the b-DNA assay, HCV-RNA levels have been shown to increase in patients with recurrent infection. The long-term consequences remain to be defined but post-transplantation HCV infection is generally much less devastating than post-transplantation HBV infection, and many patients have clinically silent disease. It is likely that a carrier state exists in immunosuppressed transplant recipients since high HCV-RNA levels occur in the absence of liver damage. In one study, 1, 2 and 3 year patient survival rates were shown to be comparable in patients with chronic active HCV infection and with cryptogenic cirrhosis (94, 89 and 87%, and 84, 84 and 73%, respectively). A more recent study from the University of Pittsburgh which compared the outcome of a larger number of HCV-infected patients (n = 237) with a large number of control patients with non-viral disease (n = 801), showed that indeed HCV infection does impact negatively on both patient and graft survival (1, 2 and 3 year patient survival in the study and control groups of 78, 68 and 66% and 84, 82 and 78%, respectively, P = 0.001). Undoubtedly with time, the full impact of recurrent HCV infection will become apparent, although short-term survival is sufficiently good to warrant continued transplantation of this group of patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Hepacivirus↗
PubMedDate not supplied

Hepatitis B and C viruses: molecular identification and targeted antiviral therapies.

Four agents are in clinical development for the treatment of chronic hepatitis B infection. These nucleoside analogs are incorporated into the growing DNA chain and terminate replication. Lamivudine, a cytadine analog that inhibits the synthesis of negative strand DNA from pre-genomic RNA, predictably inhibits replication and improves liver enzymes and histology in infected individuals. Following cessation of treatment, relapse is common, and genetic causes of viral resistance have been described. Other drugs for HBV infection include famciclovir, a guanosine analog that has also shown to suppress replication in immunocompetent as well as in immunocompromised patients; lobucavir, a guanosine analog; and adevfovir, an adenine nucleotide analog. The future of drug therapy against HBV likely includes combination agents with one or more nucleoside/nucleotide analogs and immune stimulants, such as interferon, or therapeutic vaccines. Recent advances in the treatment of HCV have been less impressive. An effective vaccine is greatly needed yet development in the near future is unlikely. Recommendations for therapy of chronic HCV have been proposed following the National Institutes of Health Consensus Conference. Interferon alpha is advised in patients with elevated serum alanine aminotransferases and liver histology demonstrating active hepatitis, regardless of level of pretreatment viremia or infecting genotype. Therapy should be continued for three months, at which time response should be assessed. If a biochemical and/or virological response has been achieved, treatment should be continued for a year. Trials are underway to evaluate interferon in combination with ribavirin. Recent identification of the crystalline structure of the HCV NS3 protease promises development of effective inhibitors of this critical viral enzyme.

Animals↗