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Biomedical subjects

C H Chan

Publications and source records attributed to C H Chan.

152 records · Page 9Linked to original sources
PubMedDate not supplied

Large cell lymphoma with initial presentation in the bone marrow.

This report describes 14 cases of large cell lymphoma with initial presentation as marrow involvement in the absence of peripheral lymphadenopathy. The disease affected mainly the middle-aged and elderly, with male predominance. Most patients presented with swinging fever and peripheral blood cytopenia. Reactive hemophagocytic syndrome was a common finding, causing significant morbidity and mortality. Peripheral lymphadenopathy was absent (by case selection), but involvement of the liver, spleen and paraaortic lymph nodes could be demonstrated in some cases. However, in some patients, the involvement was apparently restricted to the bone marrow. Involvement of the bone marrow was often subtle, and could be missed on causal examination. Immunohistochemical studies on eight cases showed that four exhibited a B-cell phenotype, three a T-cell phenotype and one a non-T non-B phenotype. The prognosis was poor, with survival being measured in days to weeks in most patients.

Adolescent↗
PubMedDate not supplied

Effect of a new ventilation system on health and well-being of office workers.

Sick building syndrome is the term given to a heterogeneous constellation of symptoms that affects workers in modern mechanically ventilated office buildings. Although the cause is unknown, there is evidence that the local environment of the work station is an important determinant of symptoms. In this study, investigators examined the effect of a new, individually controlled ventilation system on workers' symptoms. Investigators studied two groups of workers in one mechanically ventilated office building: (1) a control group at whose worksite no intervention was made and (2) an intervention group. The intervention consisted of installation of a device that allowed each worker control over the ventilation supplied to his or her worksite. Just before, and 4 and 16 mo after installation of this device, workers completed self-administered questionnaires regarding occurrence of symptoms. The new ventilation system resulted in higher air velocities, more variable temperatures, and higher concentrations of airborne dust and fungal spores. Four months after installation, workers with the new ventilation system reported fewer symptoms that were (a) work-related (p < .05) and that were work-related and frequent (p < .05); in addition, they reported fewer symptoms that reduced their capacity to work (p < .01). Sixteen months after installation, workers with the new device reported fewer symptoms than at baseline (although not as significantly), and they indicated that the indoor air quality improved their productivity by 11%, compared with a 4% reduction of productivity among the control group of workers (p < .001). Investigators concluded that the new ventilation system, which provided the workers with individual control over ventilation, was associated with important and sustained reduction in symptoms.

Adult↗
PubMedDate not supplied

Comparison of oral ciprofloxacin and amoxycillin in treating infective exacerbations of bronchiectasis in Hong Kong.

A randomised double-blind controlled clinical trial was conducted to compare oral ciprofloxacin (500 mg b.d.) and amoxycillin (1 g t.d.s.) in the treatment of infective exacerbations of bronchiectasis. The commonest organism isolated from sputum was Pseudomonas aeruginosa, which accounted for 34% of all positive sputum cultures. Other Pseudomonas species and Haemophilus influenzae, accounted for 19%, respectively. Ciprofloxacin produced better clinical response, a higher sputum to serum antibiotic level (mean of 0.65 in the ciprofloxacin group vs. 0.18 in amoxycillin group, p = 0.0001), broader spectrum of antibacterial activity and less side-effect. It was also better tolerated by patients. The findings suggest that ciprofloxacin is an effective treatment of infective exacerbations of bronchiectasis.

Administration, Oral↗
PubMedDate not supplied

Midterm results of aortic valve reconstruction for congenital aortic stenosis with or without regurgitation.

Aortic valve is often replaced if valvular stenosis fails to be balloon dilated. Aortic valve reconstruction was performed on 4 patients from August 1993 to 1999. Their ages ranged from 1 month to 15 years (mean 8.3 years). Unicuspid aortic valve was present in three of them and bicuspid in the other one. Two patients were associated with a patent arterial duct, one aortic regurgitation, and one pulmonary stenosis. Commissurotomy was done in three of them to transform the aortic valve into tricuspid except one, in whom bicuspid valve was preserved. In one case with unicuspid aortic valve, a piece of tanned autologous pericardium was used to augment one myxomatous and retracted leaflet. The sinus of Valsalva was molded together with a bulging shape of its aortic leaflet. All four were weaned from cardiopulmonary bypass smoothly. Transesophageal echocardiography in one case prompted rebypass to decrease the degree of regurgitation from moderate to mild by further shaping of the leaflet and sinus of Valsalva. In one patient chylopericardium was complicated and subsided in 5 days after conservative treatment. All patients were doing well on follow up at 56.8 +/- 34.4 months after surgery, with trivial to mild systolic pressure gradient (20 +/- 26 mmHg; preoperatively: 88 +/- 36 mmHg) and mild regurgitation. Aortic valve reconstruction is feasible in the setting of congenital aortic stenosis in our limited experience; repair instead of replacement is recommended even when regurgitation is present.

Adolescent↗