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Biomedical subjects

G T James

Publications and source records attributed to G T James.

27 records · Page 2Linked to original sources
PubMed1976

The NH2- and COOH-terminal amino acid sequence of nuclear protein A24.

The NH2- and COOH-terminal sequence of nuclear portein A24 has been determined by automatic Edman degradation and carboxypeptidase A and B digestion. Protein A24 is of interest because it is composed in part of histone 2A (Goldknofp, I.L., and Busch, H., (1975) Biochem, Biophys. Res. Commun. 65, 951-960). The sequence of the first 37 NH2-terminal residues is: Met-Gln-Ile-Phe-Val-Lys-Thr-Leu-Thr-Gly-Lys-Thr-Ile-Thr-Leu-Glu-Val-Glu-Pro-Ser-Asp-Thr-Ile-Glu-Asn-Val-Lys-Ala-Lys-Ile-Gln-Asp-Lys-Glu-Gly-Ile-Pro- This sequence is not homologous to any known histone sequence. It contains regions of internal homology (italics). The COOH-terminal amino acid sequence is the same as that of histone 2A, naely: -His-His-Lys-Ala-Lys-Gly-Lys-COOH.

Amino Acid Sequence↗
PubMed1975

Iron removal from transferrin by a cell-free amphibian system.

1. Transferrin-bound iron was released by a cell-free solution prepared from Rana catesbeiana immature erythrocytes, showing that cellular integrity is not necessarily a requirement for this process as previously thought. 2. The biological molecule(s) involved in the removal of iron from transferrin is relatively small.

Animals↗
PubMedDate not supplied

Pharmacokinetic evaluation of para-aminosalicylic acid granules.

STUDY OBJECTIVE: To determine the bioavailability and renal elimination of para-aminosalicylic acid (PAS) and its inactive metabolite acetyl-para-aminosalicylic acid (AcPAS) from a new PAS formulation. DESIGN: (a) Single-dose pharmacokinetic study in healthy volunteers; (b) Day-1 and day-8 pharmacokinetic comparison in patients with multidrug-resistant tuberculosis (MDR-TB). SETTING: Referral hospital that specializes in the treatment of mycobacterial infections. PATIENTS: (a) Twelve healthy male and female volunteers recruited by the investigators. Eleven subjects (92%) completed the study; one subject could not maintain venous access and was removed from the study. (b) Six sequential male and female patients receiving multidrug treatment for advanced MDR-TB. All patients completed the study. INTERVENTIONS: (a) Volunteers received a single 4-g dose of enteric-coated PAS granules administered with food. Blood and urine samples were collected over 24 hours after the dose. (b) Patients received 4-g doses of enteric-coated PAS granules every 8 hours for 7 days as part of their treatment regimen. Blood samples were obtained at approximately 2, 4, and 8 hours after the first dose on day 1 and the twenty-second dose on day 8. MEASUREMENTS AND MAIN RESULTS: Concentrations of PAS and AcPAS were determined using high-performance liquid chromatography. The serum concentration-time curves from volunteers and patients showed sustained PAS concentrations, in contrast to immediate-release sodium PAS tablets. In the six patients with tuberculosis, day 8 concentrations were considerably higher than those on day 1, and all were sustained well above the PAS minimal inhibitory concentration for Mycobacterium tuberculosis. CONCLUSIONS: Para-aminosalicylic acid granules produce adequate serum concentrations and appear to be safe.

Absorption↗
PubMedDate not supplied

Pharmacokinetic evaluation of aconiazide, a potentially less toxic isoniazid prodrug.

STUDY OBJECTIVE: To determine the bioavailability and renal elimination of isoniazid, acetylisoniazid, monoacetylhydrazine, diacetylhydrazine, aconiazide, and 2-formylphenoxyacetic acid. STUDY DESIGN: Randomized, double-blind, two-period, crossover phase I study. SETTING: Pharmacokinetics unit at a referral hospital that specializes in the treatment of mycobacterial infections. SUBJECTS: Twelve healthy volunteers selected from the hospital staff. INTERVENTIONS: Subjects received aconiazide tablets 650 mg (containing isoniazid 300 mg) and isoniazid tablets 300 mg. Blood and urine samples were collected over 24 hours after the dose. MEASUREMENTS AND MAIN RESULTS: Intact aconiazide and 2-formylphenoxyacetic acid were not detected in the serum. Compared with isoniazid tablets, aconiazide's relative bioavailability (based on the area under the serum concentration-time curve) was 50.7%; its relative maximum serum concentration was 13.4%. CONCLUSIONS: Isoniazid is less bioavailable after aconiazide tablets than after isoniazid tablets. The optimum dose of aconiazide remains to be determined.

Adult↗
PubMedDate not supplied

Pharmacokinetic evaluation of thiacetazone.

STUDY OBJECTIVE: To investigate the steady-state pharmacokinetics of thiacetazone (TB-1), which is active in vitro against Mycobacterium avium complex (MAC). DESIGN: Open-label phase I study. SETTING: Specialized referral hospital. PATIENTS: Twelve healthy men and women. INTERVENTIONS: Oral TB-1 150 mg/day was administered for 7 days, followed by blood and urine collection over 48 hours. MEASUREMENTS AND MAIN RESULTS: The serum concentration versus time curves of TB-1 showed sustained concentrations, with maximum values of 1.59 +/- 0.47 micrograms/ml, time to maximum 3.30 +/- 1.18 hours, and serum half-life of 15-16 hours. Less than 25% of TB-1 was recovered unchanged in the urine over 48 hours. Rashes occurred in two subjects at the end of the 7-day dosing period and resolved without progression or sequelae. CONCLUSIONS: Based on these data, we initiated a phase II study of TB-I in patients with pulmonary MAC infection who do not have the acquired immunodeficiency syndrome.

Adult↗
PubMedDate not supplied

Pharmacokinetics of pyrazinamide under fasting conditions, with food, and with antacids.

STUDY OBJECTIVES: To determine intrasubject and intersubject variability in, and the effects of food and antacids on, the pharmacokinetics of pyrazinamide (PZA). DESIGN: Randomized, four-period, crossover phase I study. SUBJECTS: Fourteen healthy men and women volunteers. INTERVENTIONS: Subjects ingested single doses of PZA 30 mg/kg under fasting conditions twice, without a high-fat meal and with an aluminum-magnesium antacid. They also received standard dosages of isoniazid, rifampin, and ethambutol. MEASUREMENTS AND MAIN RESULTS: Serum was collected for 48 hours and assayed by gas chromatography with mass selective detector. Data were analyzed by noncompartmental methods and a compartmental analysis using nonparametric expectation maximization. Both fasting conditions produced similar results: mean PZA Cmax 53.4+/-10.4 microg/ml, Tmax 1.43+/-1.06 hours, and AUC(0-infinity) 673+/-79.7 microg x hr/ml. Fasting results are similar to those in previous reports. In the presence of antacids, subjects had a mean Cmax of 55.6+/-9.0 microg/ml, Tmax of 1.43+/-1.23 hours, and AUC(0-infinity) of 628+/-88.4 microg x hr/ml. In the presence of the high-fat meal, mean Cmax was 45.6+/-9.44 pg/ml, Tmax 3.09+/-1.74 hours, and AUC(0-infinity) 687+/-116 microg x hr/ml. CONCLUSIONS: These small changes in Cmax, Tmax, and AUC(0-infinity) can be avoided by giving PZA on an empty stomach whenever possible.

Adult↗