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Biomedical subjects

J A Pang

Publications and source records attributed to J A Pang.

At least 19 recordsLinked to original sources
PubMed1991

The use of water-soluble radical scavengers to detect hydroxyl radical formation by polymorphonuclear leukocytes.

The polymorphonuclear leukocyte secretes both O2- and H2O2 when stimulated by various soluble or particulate stimuli. Since a reaction involving iron, O2-, and H2O2 could generate the hydroxyl radical (HO.) there has been speculation that the HO. may participate in the bactericidal activity of the neutrophil. A variety of water-soluble HO. scavengers have been used to test for the participation of HO. and the results imply that HO. might participate. However, other workers have not been able to detect the formation of significant amounts of HO. by the activated neutrophil. We have examined the effect of several commonly used HO. radical scavengers on the ability of the neutrophil to secrete O2- and H2O2. Several of these compounds actively inhibit secretion without affecting the viability of the neutrophil. After considering the various complications inherent in using water soluble radical scavengers, we suggest that they only be used with well defined experimental systems.

Allopurinol↗
PubMed1989

A tuberculostearic acid assay in the diagnosis of sputum smear-negative pulmonary tuberculosis. A prospective study of bronchoscopic aspirate and lavage specimens.

OBJECTIVE: To determine whether the detection of tuberculostearic acid (TBSA) in bronchial aspirate and bronchoalveolar lavage specimens is useful for the rapid diagnosis of active pulmonary tuberculosis in patients suspected of having the disease. SETTING: A pulmonary clinic in a teaching hospital. PATIENTS: Forty patients suspected of active pulmonary tuberculosis but who failed to produce sputum or whose sputum smears were negative for acid-fast bacilli on at least 3 occasions, 29 of whom were subsequently confirmed to have tuberculosis. A group of 13 patients who were having fiberoptic bronchoscopy for other reasons served as controls. INTERVENTION: All patients had fiberoptic bronchoscopy; bronchial aspirate, bronchoalveolar lavage, and sputum specimens were obtained when possible. MEASUREMENTS AND MAIN RESULTS: All specimens were examined microscopically for acid-fast bacilli, cultured for mycobacteria, and assayed for TBSA by gas chromatography and mass spectrometry with selected ion monitoring. Only 4 of the 29 patients with tuberculosis were diagnosed by direct microscopy compared with 26 by TBSA assay. In 2 patients who required surgical biopsy for conventional diagnosis, the TBSA test was positive. There were no false-positive TBSA results in the 13 controls, but 2 of 5 sputum specimens from the 11 test patients in whom tuberculosis was excluded were falsely positive, probably because of contamination with mouth flora. Because sputum can rarely be obtained from these patients and may give false-positive results, it is not a good specimen for TBSA assay. Sensitivities and specificities of the test for the other specimens were as follows: aspirate, 0.52 (CI, 0.32 to 0.71) and 1.00 (CI, 0.75 to 1.00); lavage, 0.68 (CI, 0.46 to 0.85) and 1.00 (CI, 0.84 to 1.00); aspirate and lavage combined, 0.79 (CI, 0.60 to 0.92) and 1.00 (CI, 0.86 to 1.00). CONCLUSIONS: The TBSA assay for bronchial aspirate and bronchoalveolar lavage fluid is useful for rapidly diagnosing "smear-negative" pulmonary tuberculosis. In these specimens it is highly specific and more sensitive than microscopy. This assay could be used to diagnose other mycobacterial infections, however, it cannot distinguish among species.

Bronchoalveolar Lavage Fluid↗
PubMed1989

Special precautions reduce oropharyngeal contamination in bronchoalveolar lavage for bacteriologic studies.

Despite the use of quantitative culture, oropharyngeal contamination of bronchoalveolar lavage (BAL) specimens is still a factor that limits the usefulness of this technique in the diagnosis of lower respiratory tract infection. To investigate whether special precautions could reduce contamination, 20 noninfected patients undergoing diagnostic bronchoscopy were randomized into 2 groups of 10 patients: BAL was performed routinely in group R and with special precautions in group P. These precautions consisted of giving topical lidocaine by inhalation rather than by bolus injection, and passing the bronchoscope used for BAL through a previously inserted endotracheal tube. Quantitative culture of BAL specimens showed that 5 patients in group R (50%), but none of the patients in group P (0%), had at least 1 organism recovered in concentrations greater than or equal to 10(4) colony-forming units CFU/ml (p = 0.016). Fifteen of 39 isolates (38.5%) in group R and none of 18 isolates in group P (0%) were present in concentration greater than or equal to 10(4) CFU/ml (p = 0.001). We conclude that oropharyngeal contamination of BAL specimens can be minimized by adopting special precautions during the procedure and by using quantitative culture with 10(4) CFU/ml as the cut-off point. This may increase the specificity of the technique in the diagnosis of lower respiratory tract infection without reducing its sensitivity.

Bacteriological Techniques↗
PubMed1989

The value of computed tomography in the diagnosis and management of bronchiectasis.

In order to evaluate the usefulness of computed tomography (CT) in the diagnosis and management, as distinct from only the diagnosis, of bronchiectasis, we retrospectively reviewed the clinical, lung function, and radiological data of 38 patients suspected of having the disease. All had chest radiographs, CT scans, and bronchograms. The approach was to examine the radiological investigations with the clinical data in three stages: I, chest radiograph; II, CT; III, bronchography (BG), as if they were newly presenting cases. At the end of each stage, a decision was made either to proceed to the next stage or to stop because further investigation was considered unlikely to alter management. Apparent normality, equivocal abnormality, or unilateral abnormality were criteria for proceeding. Unfitness for surgery, unequivocal bilateral disease, or mild disease were criteria for stopping after a firm diagnosis had been made. We stopped at stage I in four patients (11%) because the chest radiograph showed bilateral bronchiectasis and two had poor lung function. We stopped at stage II in 15 patients (39%): 12 had bilateral disease on CT; three had unilateral disease on CT but their clinical features were so mild that BG was considered unjustified. Scrutiny of the CT and BG films of those patients who were judged not to require CT or BG in the retrospective review confirmed that these would not have altered their management. Of the remaining 19 patients who proceeded to stage III, BG was useful in 15 (39%) by confirming or refuting CT findings, but was not useful in four (11%) because of underfilling. We conclude that optimal use of chest radiographs and CT in patients suspected of having bronchiectasis can significantly reduce the necessity of performing BG.

Adult↗
PubMed1989

An unusual case of systemic lupus erythematosus with isolated hypoglossal nerve palsy, fulminant acute pneumonitis, and pulmonary amyloidosis.

A 53 year old Chinese man with systemic lupus erythematosus (SLE) had an isolated 12th nerve palsy and acute pneumonitis. He died of respiratory failure despite intensive treatment. A limited necropsy was performed, and amyloid deposits were identified in both lung and kidney tissue. This case is highly unusual because (a) to our knowledge an isolated hypoglossal nerve palsy associated with active SLE has never been reported; (b) only one of nine reported cases of amyloidosis in patients with SLE had amyloid deposits in the lung.

Acute Disease↗
PubMed1989

The bacteriology of bronchiectasis in Hong Kong investigated by protected catheter brush and bronchoalveolar lavage.

Bacteria often colonize the lower respiratory tract of patients with bronchiectasis. Although the role of these bacteria in the pathogenesis of the disease is uncertain, their accurate identification is important for epidemiologic and treatment purposes. Therefore, the aims of this study were: (1) to identify these bacteria in patients with bronchiectasis without cystic fibrosis using the protected catheter brush (PCB) in order to avoid oropharyngeal contamination, and (2) to compare the results of bronchoalveolar lavage (BAL) with PCB. Quantitative culture was performed on PCB and BAL specimens obtained from the most severely affected lobes of 23 patients with bronchiectasis. Results of PCB showed no significant growth (less than 10(3) colony-forming units [cfu]/ml) in nine patients and 17 significant isolates (greater than 10(3) cfu/ml) in the rest: H. influenzae, 5; P. aeruginosa, 4; K. ozaenae, 2; S. aureus, 2; P. fluorescens, 1; S. pneumoniae, 1; Veillonella, 1; and coag.-ve Staph., 1. For BAL, the results were the same (20 isolates) regardless of whether 10(4) or 10(5) cfu/ml was chosen as the cutoff point. More organisms were cultured from BAL specimens, and these included all but one of the organisms cultured from PCB. We conclude that the bacteriology of bronchiectasis in Hong Kong is different from that reported in sputum studies in the West (mainly H. influenzae, S. pneumoniae, and S. aureus), and with 10(4) cfu/ml as the cutoff point, BAL gives comparable results to PCB.

Adult↗
PubMed1988

Relapse of idiopathic pulmonary haemorrhage and glomerulonephritis associated with cytomegalovirus (CMV) infection.

A 49 year old man who developed idiopathic pulmonary haemorrhage and glomerulonephritis responded initially to immunosuppressive treatment and plasmapheresis. However, he died later from massive pulmonary haemorrhage and necropsy showed cytomegalovirus infection of the lungs. We propose that relapse of pulmonary haemorrhage may be associated with cytomegalovirus infection and that preventive measures against acquiring the virus through blood products should be considered for elective transfusions in view of the relatively good long term prognosis of this syndrome.

Cross Infection↗
PubMed1988

Alveolar soft-part sarcoma: a hormone-sensitive tumour?

Alveolar soft-part sarcoma is a rare, slow-growing, malignant tumour which metastasizes frequently to the lungs. Treatment with radiotherapy or chemotherapy is largely ineffective, and most patients die within 4 years of developing metastases. We report an unusual patient who survived 9 years after detection of pulmonary metastases. Initial treatment with cytotoxic chemotherapy was ineffective. However, during subsequent treatment with Chinese herbs when she developed galactorrhoea and amenorrhoea (probably due to drug-induced hyperprolactinaemia), her lung metastases regressed, and it is likely that this contributed to her prolonged survival. We hypothesize that alveolar soft-part sarcoma may be a hormone-sensitive tumour, and hormonal manipulation may be an alternative form of treatment which is worth considering.

Adult↗
PubMed1988

The pharmacokinetics and efficacy of slow-release theophylline with asymmetric dosing in asthmatic Chinese.

Fifteen Chinese subjects with stable asthma were given asymmetric doses of slow-release choline theophyllinate (Theobret) according to body weight; patients under 60 kg (132 lb) received 180 mg at 9 AM and 360 mg at 9 PM for six days (period 1), followed by 180 mg at 1 PM and 360 mg at 9 PM for six days (period 2); for those over 60 kg, the regimen was the same, except that they received 270 mg during the daytime and 540 mg at night. At the end of each period of treatment, concentration of theophylline was measured over 24 hours. Five patients experienced side effects, and two of these were withdrawn from the study. In the remaining 13 patients, optimal concentrations of the drug were attained during most of the 24 hours, and there were only minor pharmacokinetic differences between the two periods of treatment. Compared with observations before treatment, the total symptom score was unchanged, but the peak expiratory flow rate in the morning and evening improved, and the use of inhaled bronchodilator drugs decreased significantly. There was a trend towards progressive improvement as the duration of treatment increased, suggesting that the therapeutic effect of theophylline may lag behind the attainment of optimal concentrations. We conclude that asymmetric dosing regimens of slow-release theophylline are effective and rational in maintenance therapy for asthma and that lower total daily dosages may be more appropriate in Chinese patients when compared to those recommended for white subjects.

Adult↗
PubMed1987

Bowel haemorrhage and perforation from metastatic lung cancer. Report of three cases and a review of the literature.

Surgical emergencies caused by bowel metastases from carcinoma of the lung are very rare. A search of the English literature revealed less than 10 cases of bowel perforation and no case of haemorrhage. In this report, we describe three patients with both bowel perforation due to metastases from primary lung tumours (one epidermoid; two adenocarcinoma). In two of these, bleeding occurred several days before perforation, suggesting that bowel haemorrhage may be a warning of impending rupture. It may be reasonable to consider early laparotomy to control haemorrhage and prevent perforation even in such patients despite the presence of disseminated malignant disease.

Adenocarcinoma↗
PubMed1987

Ultrasound-guided tissue-core biopsy of thoracic lesions with Trucut and Surecut needles.

The value of ultrasound-guided tissue-core needle biopsy was assessed in 54 patients with thoracic lesions adjacent to the chest wall. Of these, six were apical and two mediastinal. Biopsy was performed with Trucut or Surecut (modified Menghini) needles in 22 patients, and with both in 32 patients in order to compare the two types of needle. Definitive diagnosis was made in 46 patients (85 percent), of whom 41 had malignancy of various cell types, and five had benign lesions. Of the remaining eight, three had apical lesions, and two had consolidation distal to a proximal tumor. There was complete histologic agreement in 25 of 32 patients where biopsy was performed with both needles. Roentgenographic size of the lesion had relatively little influence on the diagnostic yield. Complications comprise moderate hemoptysis in one patient (2 percent), trivial hemoptysis or hemothorax in three, and symptomless pneumothorax in two which resolved spontaneously. We conclude that tissue core needle biopsy of thoracic lesions under ultrasound guidance is an accurate and safe technique which provides specimens adequate for routine histologic examination. The diagnostic yield from Trucut and Surecut biopsies is comparable.

Adult↗
PubMed1986

Shoshin beriberi: an underdiagnosed condition?

Shoshin beriberi, a fulminant form of heart failure due to thiamine deficiency has a different presentation to the classical form of beriberi heart failure. It is characterized by a cold periphery, low blood pressure, renal shutdown and a severe metabolic acidosis. The true incidence is unknown. Two patients were seen within a few months in a general hospital and in both dietary deficiency of thiamine was a major factor.

Acute Disease↗