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Biomedical subjects

T Y Ti

Publications and source records attributed to T Y Ti.

32 records · Page 2Linked to original sources
PubMed1988

A simple high-performance liquid chromatography method for measuring serum cloxacillin in eight Asian patients.

A simple reversed-phase high-performance liquid chromatography method using probenecid as internal standard was used for the quantitation of serum cloxacillin in eight Asian patients. The method does not require the extraction of the antibiotic from serum and the percentage recovery of cloxacillin was 96-103%. The presence of ampicillin, fusidic acid, benzylpenicillin, and gentamicin in serum appeared not to interfere with the method. The day-to-day coefficient of variation of the method over 6 months for 4-120 micrograms/ml ranged between 6.2 and 11.5%. In the eight patients in whom cloxacillin was administered intravenously or orally, there was great interindividual and intra-individual variation in the serum concentrations attained. The highest concentration of 85 micrograms/ml was obtained in a sample taken 1.5 h after an intravenous dose of 1 g. The lowest concentration of less than 1 microgram/ml was from a sample taken 6 h after an oral dose of 500 mg.

Chromatography, High Pressure Liquid↗
PubMed1988

Murine typhus infection complicated by dengue haemorrhagic fever.

Murine typhus is endemic in many South East Asian countries but it has not been reported from the island of Borneo. Recently we attended to an English lady who contracted the disease in Brunei. Her clinical course unexpectedly turned stormy in the third week of the illness accompanied by severe thrombocytopenia. She made a complete recovery. Serological studies here and subsequently in England confirmed that she suffered from recent murine typhus infection complicated by dengue haemorrhagic fever.

Adult↗
PubMed1987

The effect of dapsone-pyrimethamine on immunoglobulin concentrations in malaria chemoprophylaxis.

Immunoglobulins IgG, IgM, IgA were estimated on 3 occasions in 59 male volunteers who were taking dapsone-pyrimethamine once weekly (dapsone: 100 mg + pyrimethamine: 12.5 mg) for malaria chemoprophylaxis. Immunoglobulins IgG and IgM measured at the 7th week of chemoprophylaxis were significantly lower than baseline values (using Students' t-test for paired data), but none of the values were below 700 mg% for IgG or 30 mg% for IgM. Immunoglobulin concentrations estimated in 45 of the 59 men 6 weeks after discontinuation of chemoprophylaxis showed a return to baseline for IgM but not IgG, which remained low. On all 3 occasions there was no significant change in the IgA concentrations. The clinical implication of these findings is not known. Further studies are required to define the effects of antimalarial drugs on the antibody response to infection and immunization.

Adolescent↗
PubMed1986

Economical modification of a radioimmunoassay of digoxin with negligible interference from cord and neonatal sera.

The Amerlex digoxin radioimmunoassay was modified to reduce the running cost by five times. The modified method compared well with the original method (y = 1.0138x + 0.00916, r = 0.9936). Using the modified method, the performance with the American Association for Clinical Chemistry quality control program was consistently satisfactory for 1 year. When normal cord and neonatal sera were tested with the modified method, 41% of the 22 samples of cord serum and 68% of the 19 samples of neonatal serum produced digoxin levels less than or equal to 0.05 ng/ml. The highest digoxin level produced by cord and neonatal sera was 0.3 ng/ml.

Digoxin↗
PubMed1985

Simultaneous estimation of serum concentrations of dapsone, monoacetyldapsone, and pyrimethamine in Chinese men on maloprim for malaria prophylaxis using reversed-phase high performance liquid chromatography.

A reversed-phase high performance liquid chromatography method was developed to simultaneously estimate serum concentrations of dapsone (DDS), monoacetyldapsone (MADDS), and pyrimethamine (PYR) in 34 young adult Chinese men after they had taken the sixth weekly dose of Maloprim for malaria prophylaxis. Serum concentrations of DDS, MADDS, and PYR after 24 h were (mean +/- SEM) 374 +/- 31.3, 310 +/- 30.4, and 121 +/- 7.9 ng/ml, respectively. The 72-h serum concentrations of DDS, MADDS, and PYR were (mean +/- SEM) 134 +/- 21.6, 115 +/- 17.9, and 80 +/- 7.2 ng/ml, respectively. Serum concentrations of DDS and MADDS in many subjects after 120 h were less than 20 ng/ml, while mean +/- SEM concentration of PYR was 53 +/- 5.6 ng/ml. Acetylator phenotyping of the subjects showed that there were 31 (91%) fast acetylators, three (9%) intermediate acetylators, and no slow acetylators.

Acetylation↗
PubMed1985

Ceftriaxone therapy in bacteremic typhoid fever.

The efficacy and safety of ceftriaxone in the treatment of bacteremic typhoid fever was studied in 14 patients. Ceftriaxone at a dosage of 50 to 60 mg/kg per day was administered intravenously in two divided doses in 13 patients and as a single dose in 1 patient. When the two patients with medical complications causing persistent fever and the patient who was febrile during therapy were excluded from the calculations, the mean period of defervescence was 4 days. Five to eight days of ceftriaxone therapy was adequate for the patients who were cured. The 14 patients treated with ceftriaxone included 13 patients who were considered cured, although 1 was a convalescent carrier, and one patient who was a treatment failure. There were no relapses in the 11 patients who were monitored for 1 to 8 months. Both peak and trough concentrations of ceftriaxone were well above the ceftriaxone MICs for the Salmonella typhi strains isolated from the patients. We have demonstrated that ceftriaxone can be used successfully in the treatment of typhoid fever in some patients. The advantages of its use include rapid clinical response, short course of treatment, and lack of serious adverse drug reactions.

Adolescent↗
PubMed1985

A comparative study of the use of choline theophyllinate and a sustained-release theophylline in adults with chronic asthma.

We studied 16 adults with chronic bronchial asthma by measuring the plasma theophylline concentrations and evaluating clinically the control of asthma following oral administration of choline theophyllinate (CT) and a sustained-release theophylline preparation (SRT). All 16 patients were studied in 3 one-weekly phases. These patients received CT 200 mg t.i.d. during the 1st week, no theophylline during the 2nd week and SRT 250 mg 12-hourly during the 3rd week. All other anti-asthmatic medications were maintained during the study. After the night dose of a theophylline preparation, the mean plasma trough concentration the next morning was significantly higher for SRT (9.4 mcg/ml +/- SEM 1.0) than for CT (3.6 mcg/ml +/- SEM 0.6). The mean plasma peak concentration after the morning dose was also significantly higher for SRT (11.5 mcg/ml +/- SEM 1.0) than for CT (7.4 mcg/ml +/- SEM 1.0), The mean forced expiratory volume in one second (FEV1) obtained during SRT treatment was significantly higher than during CT treatment. There was no significant difference between FEV1 measured at trough concentrations during CT treatment and during the period without theophylline. The patients had fewer symptoms of asthma and fewer side-effects from theophylline during the week they received SRT compared with the week they received CT. In this study, using the conventional dosage schedule as practised in Singapore, SRT has distinct advantages over CT in the treatment of chronic asthma.

Administration, Oral↗
PubMed1984

Kinetic disposition of intravenous ceftriaxone in normal subjects and patients with renal failure on hemodialysis or peritoneal dialysis.

The kinetic disposition of a single intravenous dose of ceftriaxone (250 to 665 mg) was studied in six normal subjects and nine patients with renal insufficiency and normal hepatic function. In normal subjects, ceftriaxone was eliminated with a t1/2 beta of 5.2 h (range, 4.1 to 5.8). The total body clearance (Qb) was 13.5 ml/kg per h (range, 8.4 to 23.3), and renal clearance was 8.3 ml/kg per h (range, 5.8 to 13.3). In patients with severe renal insufficiency requiring peritoneal or hemodialysis, the mean t1/2 beta was prolonged to 13.4 h (range, 7.7 to 15.8) and the mean Qb was reduced to 6.9 ml/kg per h (range, 3.4 to 12.8). The apparent volumes of distribution (Vc and Vss) were not different from those determined in normal subjects. Peritoneal dialysis did not remove ceftriaxone. The dialysate of three patients on continuous peritoneal dialysis did not contain any measureable ceftriaxone, and the kinetic disposition in these patients was similar to the hemodialysis patients between their dialysis treatment. During a 4-h hemodialysis session, the total body clearance of ceftriaxone was reduced, perhaps secondary to a decrease in hepatic blood flow induced by the hemodialysis procedure. After a 12- or 24-h dose regimen, predicted trough concentrations of ceftriaxone in plasma at steady state derived from kinetic data generated from the study and assuming linear pharmacokinetic behavior were well above the minimum inhibitory concentrations of most sensitive bacteria, suggesting the feasibility of a once-a-day dosage regimen especially for patients with severe renal insufficiency.

Adult↗
PubMed1980

Propranolol and chlordiazepoxide effects on cardiac arrhythmias during alcohol withdrawal.

The pattern of cardiac arrhythmias and their treatment, by propranolol and chlordiazepoxide, during the first 48 hr of alcohol withdrawal has been studied. Prior to treatment, the incidence of serious and life-threatening arrhythmias was found to be very low and uncorrelated with most biochemical parameters. Propranolol treatment, while efficacious in controlling arrhythmias, was limited due to its association with hallucinations. Chlordiazepoxide was associated with poor early control of arrhythmias. The combination of propranolol and chlordiazepoxide was found to perform best overall with substantial reductions in arrhythmias and the fewest treatment failures.

Alcoholism↗
PubMed1979

Antihypertensive efficacy of propranolol given twice daily.

The therapeutic efficacy of propranolol in four and two daily doses was compared in 63 treated hypertensive patients in a multicentre trial. After 3 months of a stable diastolic blood pressure while receiving propranolol four times a day the patients were switched to a twice-a-day regimen, the drug being given at 8 am and 8 pm, with the same total daily dose, for 3 more months. Blood pressures and heart rates were measured at 8 am, 12 noon, 4 pm and 8 pm at 4-week intervals. There were no significant changes in mean blood pressure after the change to the twice-a-day regimen, although some patients reported new side effects. Compliance appeared to be unaffected.

Adolescent↗