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Biomedical subjects

W W Yew

Publications and source records attributed to W W Yew.

At least 91 records · Page 5Linked to original sources
PubMed1993

Correlation of serum ofloxacin concentration and serum creatinine level in patients on prolonged therapy.

Serum ofloxacin concentrations were assessed by high performance liquid chromatography 4 h after drug administration in 86 patients with pulmonary tuberculosis. All patients had multidose, once-daily drug administration (200 mg to 800 mg p.o.) for at least 3 weeks prior to assessment. The serum creatinine levels were simultaneously assessed for these patients. A positive correlation was found between serum ofloxacin (Y) and serum creatinine x dose of ofloxacin administered/body surface area (X). The correlation can be represented mathematically by the equation: Y = 0.87X + 0.68 (r = 0.80, p < 0.001).

Adolescent↗
PubMed1993

Lack of activities of amikacin and sulphamethoxazole against Mycobacterium avium-intracellulare.

Twenty clinical isolates of Mycobacterium avium-intracellulare were tested with amikacin and sulphamethoxazole for in-vitro susceptibilities. The MICs and MBCs of the former drug ranged from 8 to > 64 mg/L (median MIC: 64 mg/L, median MBC: > 64 mg/L). The MICs and MBCs of the latter drug were found to be > 256 mg/L. Each of eight patients with invasive pulmonary disease due to these organisms was treated with amikacin for six months and with cotrimoxazole (sulphamethoxazole-trimethoprim) for one year. Only one patient had sustained bacteriological conversion. Three patients showed a transient reduction of bacillary load during the period of amikacin administration. The rest all failed to show response. Thus sulphamethoxazole was found to have no activity against Mycobacterium avium-intracellulare, and amikacin has doubtful activity when used alone in treatment of M. avium-intracellulare infection.

Adult↗
PubMed1992

Incidence of ras oncogene activation in lung carcinomas in Hong Kong.

BACKGROUND: In Hong Kong, lung carcinomas contribute to the majority of cancer deaths among Chinese. Point mutational activation of ras oncogenes has been observed in several populations. The incidence of these mutations in Hong Kong lung carcinomas was investigated. METHODS: Lung resections obtained from 52 Chinese patients whose conditions were newly diagnosed as non-small cell lung cancer, paraffin sections from 29 Chinese patients with previously diagnosed adenocarcinoma of the lung, and paraffin sections from 49 squamous cell carcinomas were examined for the presence of point mutations in Ki-ras codon 12, N-ras codon 61, and Ha-ras codon 12 oncogenes by allele-specific hybridization after specific amplification of appropriate regions of the DNA using the polymerase chain reaction. RESULTS: Among the 130 lung carcinomas investigated, Ki-ras point mutations were detected in seven cases, of which six were adenocarcinomas and one a squamous cell carcinoma. No mutations were detected in the N-ras and Ha-ras codons. CONCLUSIONS: The incidence of Ki-ras codon 12 point mutational activation in Chinese patients with adenocarcinomas was 6 of 63 (9.5%). The incidence of Ki-ras 12 point mutational activation among men with lung adenocarcinomas in Hong Kong (6 of 32 patients, 18.8%) is significantly different from that in women in Hong Kong (0 of 31 patients, 0%). Although ras oncogenes are implicated as having a role in the development of lung adenocarcinomas, especially among smokers, it is clear from these data that they are not associated with the unusually high incidence of lung adenocarcinomas among women in Hong Kong.

Adenocarcinoma↗
PubMed1992

The early bactericidal activity of rifabutin measured by sputum viable counts in Hong Kong patients with pulmonary tuberculosis.

Previously untreated patients with smear-positive pulmonary tuberculosis were randomly allocated to treatment with 600, 300, 150 or 75 mg doses of rifabutin (LM427, ansamycin), 600, 300 or 150 mg of rifampicin, 300 mg isoniazid or to no drug daily for 2 days. The fall in viable counts of Mycobacterium tuberculosis in sputum collections during the 2 days, termed the early bactericidal activity (EBA), was estimated from counts of colony-forming units (cfu) on selective 7H-11 agar medium. The EBA for rifabutin ranged from -0.039 (an increase in counts) to 0.049 log10 cfu/ml/day whereas the EBA increased from 0.071 for 150 mg rifampicin to 0.293 log10 cfu/ml/day for 600 mg rifampicin and was 0.43 log10 cfu/ml/day for 300 mg isoniazid. The difference between the EBAs for rifabutin and rifampicin just attained significance (P = 0.05) suggesting that rifabutin was inactive or less active than rifampicin against the extracellular bacilli in pulmonary cavities. Peak plasma concentrations of rifabutin after the initial doses were found to be proportional to dose size and were approximately 7 times lower than those after the same dose size of rifampicin. The lower EBA of rifabutin as compared to rifampicin is probably due to the low plasma concentrations which are not fully compensated for by slightly greater antituberculosis activity of rifabutin in vitro.

Adolescent↗
PubMed1992

Tolerance of ofloxacin in the treatment of pulmonary tuberculosis in presence of hepatic dysfunction.

Twenty-nine patients with extensive pulmonary tuberculosis and drug-induced hepatitis were treated with ofloxacin along with other relatively non-hepatotoxic drugs, either during the interim phase to await recovery of liver function in some, or as definitive therapy as required by the compromised hepatic status of others. No adverse drug reactions were noted and no treatment failures were observed. This preliminary experience indicates the exceedingly good tolerance of ofloxacin when utilized in treatment of extensive pulmonary tuberculosis in the face of deranged liver function tests. Due to the small number of patients and numerous variables, no definite conclusion can be drawn on the specific efficacy of ofloxacin against Mycobacterium tuberculosis. However, it is concluded that acquisition of further clinical experience is warranted for similar patients.

Adult↗
PubMed1991

Combined use of fine-needle aspiration cytologic examination and tuberculin skin test in the diagnosis of cervical tuberculous lymphadenitis. A prospective study.

A prospective study to evaluate the efficacy of combined use of fine-needle aspiration (FNA) cytologic examination and Mantoux test in the diagnosis of cervical tuberculous lymphadenitis was carried out. Tuberculin reactions were determined in 59 control subjects. Preoperative FNA cytologic examinations and Mantoux tests were performed on 74 patients with cervical lymphadenopathy. The lymph nodes were then excised and examined histologically and cultured for mycobacteria. Forty-eight, 22, and 4 patients had histologically confirmed tuberculous, non-specific, and malignant lymphadenopathy. Fine-needle aspiration cytologic examination alone could detect cervical tuberculous lymphadenitis in 37 patients (77%). The predictive value of a strong tuberculin reaction for mycobacterial infection was 100%. The combined use of a Mantoux test and FNA cytologic examination was able to diagnose 43 (90%) of 48 cases of tuberculous lymphadenitis cervical preoperatively. Combined use of FNA cytologic examination and Mantoux test was efficient in the diagnosis of tuberculous lymphadenitis.

Adolescent↗
PubMed1991

Percutaneous transthoracic needle biopsies in the rapid diagnosis of pulmonary tuberculosis.

From May, 1987, to December, 1990, 173 percutaneous transthoracic needle biopsies (PTNB) using a 19-gauge spinal needle under uniplane fluoroscopic guidance were performed in 160 patients. Thirty-one patients had a final diagnosis of pulmonary tuberculosis. These patients with tuberculosis underwent a total of 35 biopsies. Twenty of 35 (57%) had definite histologic features of tuberculosis with stainable acid-fast bacilli, 4/35 (11.5%) had granulomatous or caseous lesion consistent with tuberculosis, and 11/35 had nonspecific inflammatory changes. When results were matched with the sputum culture results, 15/35 specimens (43%) provided the exclusive means of diagnosis of tuberculosis. Five of 35 (14%) patients developed postbiopsy pneumothoraces. The overall acceptance by patients was good. This report indicates the potential usefulness of PTNB in the rapid diagnosis of selected cases of suspected pulmonary tuberculosis. The yield was comparable to fiberoptic bronchoscopy, currently commonly used in the diagnosis of pulmonary mycobacterial disease. The procedure was noted for its simplicity.

Biopsy, Needle↗
PubMed1991

Ofloxacin penetration into tuberculous pleural effusion.

After 3 days of treatment with ofloxacin (300 mg given orally once daily), the drug levels in serum and pleural fluid 2 and 4 h after drug administration in patients with tuberculous pleural effusion were assessed by a rapid high-performance liquid chromatography assay. The levels in serum (mean +/- standard error of the mean [SEM]) were 4.70 +/- 0.14 and 4.63 +/- 0.09 mg/liter 2 and 4 h after administration, respectively, and the levels in pleural fluid (mean +/- SEM) were 3.82 +/- 0.09 and 4.21 +/- 0.08 mg/liter, respectively. The pleural fluid-to-serum ofloxacin ratio at 2 h was 0.82 +/- 0.02 (mean +/- SEM), and the ratio at 4 h was 0.92 +/- 0.02 (mean +/- SEM). This study demonstrated very good penetration of ofloxacin into pleural fluid in tuberculous pleuritis.

Adult↗
PubMed1991

Diagnosis of tuberculous pleural effusion by the detection of tuberculostearic acid in pleural aspirates.

Detection of TBSA was attempted in pleural aspirates of 74 patients with tuberculous and 44 patients with nontuberculous pleural effusion by gas chromatography/mass spectrometry with selected ion monitoring. The results were disappointing with a test sensitivity of 67.6 percent and a specificity of 52.3 percent. In contrast, histologic examination of pleural biopsies gave a diagnostic sensitivity of 71.0 percent. Pleural biopsy remains a better investigational procedure for the diagnosis of tuberculous pleural effusion.

Biopsy↗
PubMed1990

Ofloxacin and imipenem in the treatment of Mycobacterium fortuitum and Mycobacterium chelonae lung infections.

Two patients with Mycobacterium fortuitum and one patient with Mycobacterium chelonae lung infections were treated with ofloxacin and imipenem respectively. Of the former two, one had underlying inactive pulmonary tuberculosis and bronchiectasis and the other had silicosis. The latter had severe underlying bronchiectasis also. The treatments were well tolerated and the patients responded well.

Adult↗
PubMed1990

Minimal bactericidal and inhibitory concentrations of ofloxacin on Mycobacterium fortuitum at pH 7 and 5: therapeutic implications.

Mycobacterium fortuitum infections of sternotomy wounds have been successfully treated with ofloxacin, a fluoroquinolone. We studied the MBCs and MICs in vitro of this antibiotic on the organism under neutral pH (7) and acidic pH (5) and found marked escalation of these values under the latter condition. This provides hints on the therapy of these infections under in vivo settings.

Culture Media↗
PubMed1990

In-vitro activity of ofloxacin against Mycobacterium tuberculosis and its clinical efficacy in multiply resistant pulmonary tuberculosis.

The in-vitro susceptibilities to ofloxacin of 159 clinical sputum isolates of Mycobacterium tuberculosis, comprising 95 isolates sensitive to all drugs, 31 isolates resistant to streptomycin or isoniazid or both, 27 isolates resistant to streptomycin, isoniazid and rifampicin and six isolates resistant to rifampicin (and in three cases to other drugs) were determined. Favourable MICs of ofloxacin (0.63-1.25 mg/l) were demonstrated for 147 isolates (92%). Twenty-two patients with resistant strains (including one patient with rifampicin intolerance) were studied: ten were given 300 mg ofloxacin and ten were given 800 mg ofloxacin, once daily in both cases, together with second-line accompanying drugs, for nine months to one year. Two received 800 mg of ofloxacin once daily alone for similar periods. In the 300 mg-ofloxacin group and the 800 mg-ofloxacin group, five and eight patients, respectively, achieved culture conversion; the rest failed. In the former group, the peak serum ofloxacin concentrations were 3.71-8.08 mg/l and the mean sputum/serum ratio was 0.85. In the latter group, the corresponding values were 10-18.7 mg/l, and 0.76, respectively. All patients tolerated the drugs well. Analysing only patients with accompanying drugs, those on ofloxacin 800 mg once daily had more rapid sputum culture conversion than those on ofloxacin 300 mg once daily (Mann-Whitney Wilcoxon Rank Sum Test: P less than 0.05), indicating more rapid bacteriolysis and implying the definite efficacy of ofloxacin when used together with second-line accompanying drugs in the management of resistant tuberculosis.

Adult↗
PubMed1990

Nosocomial tuberculosis in hospital staff. The size of the problem in a Hong Kong chest hospital.

In the past three decades, among 831 staff (over 6,862 staff-years) under regular chest radiographic survey in the Grantham Hospital, Hong Kong, the cumulative incidence of active pulmonary tuberculosis requiring treatment was 27 (belonging to 23 staff). Number of cases detected per year ranged from 0 to 3. The mean duration from the beginning of employment to the first evidence of disease was 6.43 years. Although this incidence is low, yet the hospital caters for quite a large number of patients with bacteriologically confirmed tuberculosis, we feel that the active screening program for hospital staff should be maintained, and that review of the situation is also recommended.

Adolescent↗