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Biomedical subjects

J D Hulse

Publications and source records attributed to J D Hulse.

23 records · Page 2Linked to original sources
PubMed1978

Carnitine biosynthesis. beta-Hydroxylation of trimethyllysine by an alpha-ketoglutarate-dependent mitochondrial dioxygenase.

Rat liver mitochondria were found to hydroxylate epsilon-N-trimethyl-L-lysine to produce beta-hydroxy-epsilon-N-trimethyl-L-lysine, an intermediate in carnitine biosynthesis. The hydroxylating system requires alpha-ketoglutarate, Fe2+, and ascorbate, but does not require NADPH nor NADH. No activity was found in the microsomal or soluble fractions of liver extracts. The hydroxylated alpha-amino acid was isolated and characterized by column chromatography using Dowex 50-H+ and Chelex 100-Cu2+ resins and by high voltage paper electrophoresis. The enzymatically produced beta-hydroxy-epsilon-N-trimethyl-L-lysine was shown to be periodate-sensitive and one periodation product was characterized as gamma-butyrobetaine aldehyde. The hydroxylated product was acted upon by crystalline serine transhydroxymethylase (EC 2.1.2.1) to yield gamma-butyrobetaine aldehyde and glycine. Conversion of about 40% of the epsilon-N-trimethyl-L-lysine to beta-hydroxy-epsilon-N-trimethyl-L-lysine was accomplished by this system with little or no further metabolism.

Animals↗
PubMedDate not supplied

Ganciclovir absolute bioavailability and steady-state pharmacokinetics after oral administration of two 3000-mg/d dosing regimens in human immunodeficiency virus- and cytomegalovirus-seropositive patients.

Oral ganciclovir has recently been approved for use in long-term maintenance therapy in the treatment of cytomegalovirus (CMV) retinitis in immunocompromised patients. Although oral ganciclovir at a dose of 3,000 mg/d is moderately less effective than intravenous (i.v.) ganciclovir maintenance therapy (5 mg/kg as a 1-hour i.v. infusion every 24 hours), convenience and practicality make oral maintenance therapy desirable. Two dosing regimens--1,000 mg three times daily (TID) and 500 mg every 3 hours (six times daily)--have been shown to be efficacious. Eighteen human immunodeficiency virus- and CMV-seropositive patients participated in a three-way, open-label, crossover study to evaluate the steady-state pharmacokinetics and absolute bioavailability of the two oral regimens compared with the i.v. regimen. Sixteen patients completed the study and received ganciclovir as a single 5-mg/kg i.v. infusion over 1 hour, 500 mg orally every 3 hours while awake (six times daily) for 3 days, and 1,000 mg TID orally for 3 days. Blood samples were obtained over a 24-hour period after the single i.v. dose and on day 3 of the oral dosing regimens. Mean peak serum concentrations were 8.27, 1.02, and 1.18 micrograms/mL for the i.v. and oral regimens, respectively. Twenty-four-hour area under the curve (AUC) for the oral regimens--500 mg every 3 hours and 1,000 mg TID--were 15.9 and 15.4 micrograms.h/mL, respectively, as compared with a total AUC of 22.1 micrograms.h/mL for the single i.v. dose. The absolute bioavailabilities for the two oral regimens were 8.84% and 8.53%, respectively. The extent of ganciclovir absorption, peak concentrations, and average concentration at steady state were not statistically different between the two oral regimens. The peak-to-trough concentration ratio (Cmax:Cmin) was greater for the 1,000-mg TID regimen than for the regimen of 500 mg every 3 hours (5.35 vs 3.81 [P < 0.01]). Both oral regimens resulted in concentrations in the range of the concentration that inhibits 50% of most human CMV isolates. Because both oral regimens provide equivalent absorption, the 1,000-mg TID regimen may be preferred for the convenience and potentially greater compliance associated with fewer daily doses.

Administration, Oral↗
PubMedDate not supplied

Effects of intensive granulocyte donation on donors and yields.

Thirteen HLA-identical bone marrow donors served as the sole source of daily granulocyte transfusions for respective marrow recipients during the period of severe neutropenia between transplantation and engraftment. They experienced 12 to 29 (median, 17) daily, continuous flow centrifugation leukapheresis procedures using hydroxyethyl starch, but no corticosteroids, with little serious difficulty. No immediate clinical reactions occurred in 90 percent of 228 procedures. Mild citrate reactions were noted in 9 percent, and only two procedures (0.8%) were discontinued due to severe reactions. Ten donors (77%) answered a questionnaire mailed weeks later, and six reported transient, late clinical adverse effects. Five had moderate dermatologic problems; one had minimal hypertension requiring no therapy. Donors were monitored daily for laboratory abnormalities while donating granulocytes. Hemoglobin concentration and platelet counts remained stable (autologous red cell transfusions had been given). Blood leukocyte counts gradually fell (p less than 0.05), particularly after 10 or more daily granulocyte donations, and this fall was associated with a decrease of about 33 percent in leukocyte yields. No attempts were made to improve yields by giving higher doses of hydroxyethyl starch or by corticosteroid stimulation. With primary emphasis on donor safety, it seems feasible for a few compatible donors to provide prolonged granulocyte transfusion support for designated patients. However, diminishing leukocyte yields may result from intensive, repeated leukapheresis.

Blood Donors↗