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Biomedical subjects

H C Yang

Publications and source records attributed to H C Yang.

106 records · Page 6Linked to original sources
PubMed1978

Immunologic studies of factor IX (Christmas factor). II. Immunoradiometric assay of factor IX antigen.

A solid-phase two-site immunoradiometric assay has been developed which measures factor IX antigen levels as low as 0.0004 u per ml of plasma. In normal individuals, the factor IX antigen level correlated with the factor IX procoagulant level. In haemophilia B, 14 patients had markedly reduced antigen levels (less than 0.06 u/ml) and five had normal levels (greater than 0.60 u/ml).

Antigens↗
PubMed1978

Detection of hemophilia A carriers by use of frozen plasma samples.

The efficacy of using promptly frozen plasma samples in the diagnosis of the carrier state for hemophilia A was evaluated by simultaneous measurement of factor VIII acitivity and antigen in 20 normal women and 20 obligate carriers. Factor VIII antigen was measured by two methods, electroimmunoassay and immunoradiometric assay. When the factor VIII activity and antigen data were evaluated by regression analysis, 94% of the carriers were correctly identified at the 95% confidence level.

Antigens↗
PubMed1977

Procoagulant specificity of factor VIII inhibitor.

Nine haemophilia A patients with an inhibitor to factor VIII procoagulant and eight without an inhibitor were studied for the presence of an inhibitor to von Willebrand factor (vWf) in a quantitative ristocetin-induced platelet aggregation system. The mean vWf, factor VIII related antigen (FVIII Ag) and vWf:FVIII Ag ratio were not significantly different in the two groups (P greater than 0.6). The inhibitor plasmas did not reduce the wWf level in normal plasma after a 2 h incubation. The factor VIII inhibitor is highly specific for the procoagulant function of the factor VIII complex.

Antigens↗
PubMedDate not supplied

Factor VIII procoagulant and antigen content of antihemophilic factor (AHF) concentrates.

Antihemophilic factor concentrates from six manufacturers were studied for factor VIII procoagulant and antigen content. Marked lot-to-lot differences were found in the factor VIII antigen:procoagulant ratio. The average antigen content was 2.33 times that of procoagulant activity in 21 lots studied, indicating a significant loss of activity during the fractionation process.

Antigens↗
PubMedDate not supplied

Combined effect of amphotericin B and flucytosine on hyphal growth of Candida albicans estimated at a single hypha level.

The in vitro efficacy of amphotericin B and flucytosine, separately and in combination, against the hyphal growth of Candida albicans was evaluated in situ using an automatic analysing system. A colony of C. albicans was in contact with a glucose-salt medium supplemented with biotin plus calf serum (GS medium) and GS medium containing the antifungal agent, in sequence. Minimum inhibitory concentrations at single hyphal level (S-MIC) were determined based on the response that was measured. Amphotericin B S-MICs ranged from 0.8 to 0.4 microgram ml-1, and S-MIC values > 102.4 micrograms ml-1 were obtained with flucytosine when the two agents were used independently. When the two agents were used in combination, however, a synergistic interaction between the two agents at concentrations below their individual S-MICs was observed.

Amphotericin B↗
PubMedDate not supplied

Elevation of renal glutathione enhances ischemic injury.

In a previous study, we tested the hypothesis that an elevated level of renal glutathione (GSH) would protect the kidney from ischemic injury. However, prior elevation of GSH with GSH monoethylester enhanced then injury induced by 35 min of ischemia and blood reflow [Scaduto RC Jr, Gattone VH, Grotyohann LW, et al; Effect of an altered glutathione content on renal ischemic injury. Am J Physiol 1988;255:F911-F921]. Additionally, GSH monoethylester produced morphologic alterations in the absence of ischemia. Thus the greater ischemic injury observed after GSH ester pretreatment could have been due to a synergistic effect between the events caused by ischemia and the pretreatment. The present study was conducted to evaluate the utility of elevating renal GSH levels by administration of GSH. Administration of GSH (1 mmol/kg body weight) caused a 3-fold elevation of renal GSH levels and a 6-fold elevation of renal cysteine levels after 60 min without causing changes in renal morphology or GFR. After 35 min of renal artery occlusion and 90 min of blood reflow, animals pretreated with GSH had a much greater decline in GFR than untreated control animals. This enhancement of renal ischemic injury in GSH-treated animals was similar to that observed following administration of GSH monoethylester. We conclude that administration of GSH is the method of choice for elevation of renal GSH and that elevation of renal GSH leads to an enhanced ischemia-induced injury which is independent of the method employed to elevate renal GSH.

Adenine Nucleotides↗
PubMedDate not supplied

Cholecystectomy in the potential heart transplant patient.

The management of cholelithiasis with gallstone pancreatitis in the heart transplant candidate is a difficult problem. Biliary tract surgery in the heart transplant candidate presents an additional set of clinical risks in view of extensive heart disease. We report the cases of three patients with symptomatic cholelithiasis with gallstone pancreatitis who were successfully operated on while awaiting cardiac allografts. Each patient was preoperatively prepared with (1) a lumbar epidural catheter for postoperative pain control with epidural opioids, (2) a balloon-tipped (Swan-Ganz) catheter and arterial line for perioperative monitoring, and (3) an intraaortic balloon pump for circulatory support with full heparinization after epidural catheter placement. In addition, preoperative optimization of cardiovascular function with pharmacologic agents was carefully achieved for 6 to 12 hours before surgery. All three patients had stable intraoperative courses, with less than a 300 ml blood loss. Their postoperative outcomes were without surgical complication. We think that biliary tract surgery may be safely accomplished in the heart transplant candidate with careful, appropriate preparation and meticulous surgical technique. We also present our management algorithm for heart transplant patients with cholelithiasis before and after operation.

Algorithms↗