Biomedical subjects

B W Van de Wal

Publications and source records attributed to B W Van de Wal.

7 recordsLinked to original sources

PubMed2003

Diagnostic tools in tuberculous pleurisy: a direct comparative study.

Thoracoscopy is the most accurate yet most expensive tool for establishing the diagnosis of tuberculous (TB) pleurisy. However, most high TB-incidence regions have limited financial resources, lack the infrastructure needed for routine thoracoscopy and require an alternative, cost-effective diagnostic approach for pleural effusions. Altogether, 51 patients with undiagnosed exudative pleural effusions were recruited for a prospective, direct comparison between bronchial wash, pleural fluid microbiology and biochemistry (adenosine deaminase (ADA) and cell count), closed needle biopsy, and medical thoracoscopy. The final diagnosis was TB in 42 patients (82%), malignancy in five (10%) and idiopathic in four patients (8%). Sensitivity of histology, culture and combined histology/culture was 66, 48 and 79%, respectively for closed needle biopsy and 100, 76 and 100%, respectively for thoracoscopy. Both were 100% specific. Pleural fluid ADA of > or = 50 U x L(-1) was 95% sensitive and 89% specific. Combined ADA, lymphocyte/neutrophil ratio > or = 0.75 plus closed needle biopsy reached 93% sensitivity and 100% specificity. A combination of pleural fluid adenosine deaminase, differential cell count and closed needle biopsy has a high diagnostic accuracy in undiagnosed exudative pleural effusions in areas with high incidences of tuberculosis and might substitute medical thoracoscopy at considerably lower expense in resource-poor countries.

Adenosine Deaminase↗

PubMed2002

The early bactericidal activity of streptomycin.

SETTING: Patients with sputum smear-positive, newly diagnosed pulmonary tuberculosis studied at Tygerburg Hospital, Cape Town, for their early response to streptomycin (SM). OBJECTIVE: To determine the standard early bactericidal activity (EBA), namely the fall in viable counts of tubercle bacilli in 16-hour sputum collections during the first 2 days of treatment with SM. DESIGN: Patients were randomised to logarithmically spaced daily doses of 7.5, 15 or 30 mg/kg SM. A comparison by standard biological assay methods was then made with previous estimations of the EBA of paromomycin in doses of 7.5 and 15 mg/kg. RESULTS: An EBA of 0.133 obtained with 30 mg/kg SM differed significantly from zero (P = 0.0009), while the EBAs of 0.043 with 15 mg/kg and -0.025 with 7.5 mg/kg did not so differ. A linear regression equation of EBA = -0.2587 + 0.2627 log10 dose was obtained with significant slope (P = 0.007). Paromomycin was estimated to be 1.745 more potent than SM with wide 95% confidence limits (0.6-28.6), indicating that it cannot be considered more potent than SM. CONCLUSIONS: The low EBAs show that SM has low, dose-related, bactericidal activity in cavities, consistent with results from clinical trials. If streptomycin-resistant bacilli are present, paromomycin is probably the aminoglycoside of choice.

Adult↗

PubMed2001

Early bactericidal activity of amoxicillin in combination with clavulanic acid in patients with sputum smear-positive pulmonary tuberculosis.

The early bactericidal activity (EBA) of an antituberculosis agent is the rate of decrease in viable colony-forming units (CFU) per milliliter of sputum during the first 2 d of treatment of patients with previously untreated smear-positive pulmonary tuberculosis. The objective of this open randomized study was to evaluate the EBA of the combination of amoxicillin 3 g and clavulanic acid 750 mg. Ten patients with a mean age of 34 y and a mean weight of 56 kg received amoxicillin/clavulanic acid and 5 patients with a mean age of 34 y and a mean weight of 57 kg received no drug. In the patients receiving 1 dose of amoxicillin/clavulanic acid daily for 2 d the mean log10CFU/ml of sputum before treatment was 6.7402 (SD 0.539) and after 2 d of treatment 6.7046 (SD 0.609); the corresponding values in patients receiving no drug were 6.7823 (SD 0.563) and 6.7502 (SD 0.673), respectively. The EBA of 0.018 (SD 0.130) in patients receiving amoxicillin/clavulanic acid did not differ significantly from that of 0.016 (SD 0.069) in patients receiving no drug. It is unlikely that the combination of amoxicillin/clavulanic acid has an important place in the treatment of tuberculosis with the exception of those patients with multidrug-resistant tuberculosis who are otherwise therapeutically destitute.

Adult↗

PubMed2001

The early bactericidal activity of a low-clearance liposomal amikacin in pulmonary tuberculosis.

The early bactericidal activity (EBA) of a liposomal preparation of amikacin (MiKasome) with a long plasma half-life of 120-200 h was examined in seven patients with newly diagnosed, smear-positive pulmonary tuberculosis. Liposomal amikacin was given in slow iv infusions of 30 mg total amikacin/kg body weight on three successive days. Cfu counts were set up on 16 h sputum collections preceding the first dose and following each dose and were used for calculating the EBA. Despite the high concentrations of total amikacin, >1000 mg/L, obtainable in plasma, no evidence of EBA was obtained. In view of the considerable activity of liposomal amikacin in experimental murine tuberculosis, this finding indicates that liberation of amikacin from the long-life liposomes occurs only in macrophages that are not usually present in the vicinity of the large extracellular clumps of bacilli in the cavity caseum.

Adult↗

PubMed2001

The early bactericidal activity of amikacin in pulmonary tuberculosis.

SETTING: Stellenbosch University, a tertiary care hospital in Cape Town, South Africa. OBJECTIVE: To determine the early bactericidal activity (EBA) of amikacin in dosages of 5 mg/kg, 10 mg/kg and 15 mg/kg body weight in comparison to that of isoniazid 6 mg/kg body weight or no drug. DESIGN: An open, randomised trial. PATIENTS: Patients with previously untreated, sputum smear-positive pulmonary tuberculosis. INTERVENTION: Patients received amikacin 5 mg/kg (12 patients), 10 mg/kg (13 patients) or 15 mg/kg (15 patients), isoniazid 6 mg/kg (9 patients) or no drug (10 patients). RESULTS: The rate of decrease in log viable colony forming units of Mycobacterium tuberculosis per ml of sputum per day during the first 2 days of treatment with amikacin 5 mg/kg, 10 mg/kg and 15 mg/kg was 0.041 (SD 0.100), 0.045 (SD 0.144) and 0.052 (SD 0.096), respectively, 0.515 (SD 0.173) in the patients receiving isoniazid 6 mg/kg, and 0.041 (SD 0.113) in those receiving no drug. The EBA found in patients receiving amikacin did not differ significantly from that of the no drug group. However, as the EBA in the no drug group was the highest ever encountered at Stellenbosch University, the mean in patients receiving drug was tested against 0 and found to differ significantly (P = 0.03), suggesting minimal activity. Mean amikacin serum concentrations 1 hour after intramuscular drug administration were 13.5 microg/ml, 26.7 microg/ml and 39.2 microg/ml in the patients receiving 5 mg, 10 mg and 15 mg per kg body weight, respectively. CONCLUSION: Despite serum concentrations well in excess of the minimal inhibitory concentration of 2-4 microg/ml, the EBA of amikacin in patients with smear-positive pulmonary tuberculosis was only just detectable.

Adolescent↗

PubMed1997

The early bactericidal activity of isoniazid related to its dose size in pulmonary tuberculosis.

Collections of sputum from 105 patients with newly diagnosed pulmonary tuberculosis were made before and at 1 and 2 d after the start of chemotherapy with isoniazid (INH) alone given to groups of patients in doses of 600 mg, 300 mg, 150 mg, 75 mg, 37.5 mg, 18.75 mg, and 9 mg daily, as well as from an untreated group. Counts of colony forming units (cfu) of Mycobacterium tuberculosis in the collections were set up on plates of selective 7H10 medium. The early bactericidal activity (EBA) of INH was defined as the decrease in log10 cfu/ml sputum/day during the first 2 d of treatment. A smooth curve relating EBA to log dose was obtained, with 600 mg INH yielding the highest mean EBA of 0.539, and 18.75 mg INH yielding the lowest EBA (0.111) that could be distinguished from the bactericidal activity of the untreated group. The ratio of the usual dose of 300 mg INH to the lowest dose, of 18.75 mg, that produced a detectable EBA, termed the therapeutic margin, was therefore 16, in contrast to the lower therapeutic margin of 4 for rifampin. The EBA was related to the INH acetylator genotype of patients treated with 600 mg or 9 mg INH.

Acetylation↗

PubMed1997

The early bactericidal activity of ciprofloxacin in patients with pulmonary tuberculosis.

The early bactericidal activity (EBA) of ciprofloxacin (CIP) was measured in 80 patients with previously untreated, smear-positive pulmonary tuberculosis by counting viable bacilli in sputum collections during the first 2 d of treatment. Groups of about 10 patients were treated daily with graded doses of CIP or with 300 mg isoniazid or with no drug. The mean EBA, defined as the fall in log CFU/ ml sputum/d, increased from -0.011 in the no drug group to 0.046, 0.092, 0.121, and 0.205 in the groups receiving 250, 500, 1,000, or 1,500 mg CIP, respectively, a highly significant trend. These results demonstrate the antimycobacterial activity of CIP in high dosage, though the mean EBAs of 0.55 and 0.66 in two groups receiving isoniazid were much higher.

Adult↗