Search PubMed⌕ Search

Biomedical subjects

S C Chang

Publications and source records attributed to S C Chang.

At least 289 records · Page 16Linked to original sources
PubMed1990

[Epidemiologic study of pathogens causing nosocomial infections].

Nosocomial infection is a global problem. It significantly adds to the expected duration of hospitalization resulting with an increased economic burden and represents a leading cause of death. The characteristics of nosocomial infection vary from country to country and also changes with time. In order to understand the pathogens causing nosocomial infection in the large teaching hospital in Taiwan, we collected and analysed the surveillence data of nosocomial infection at the National Taiwan University Hospital from 1981 to 1989. We found that the nosocomial infection rate had been around 4-5% annually since 1981 till 1989. As ranked according to the site of infection, surgical wound infections were the most common, followed by the urinary tract, respiratory tract, and blood stream infections. However, the incidence of surgical wound infections had decreased gradually. About one third of nosocomial infections were caused by multiple microorganisms. The most frequently isolated pathogen has changed from Escherichia coli in early years to Pseudomonas aeruginosa in the most recent years. Gram-negative aerobic bacteria has been the major pathogens resulting in nosocomial infections for the past 9 years, accounting for 55-66%. In contrast, fungi have increased rapidly from 1.8% of total isolates in 1981 to 7.7% in 1989. Gram-positive cocci have also increased in recent years. The leading pathogen by infection site was P. aeruginosa in surgical wound infections, E. coli in urinary tract infections, and P. aeruginosa in respiratory tract infections. In earlier years E. coli was the major isolate in bacteremic cases, but glucose non-fermenters, including P. aeruginosa, Acinetobacter calcoaceticus and others, plus Enterobacter species-emerged as the major pathogens of recent years.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗
PubMed1990

[Preparation of toxoid from Taiwan cobra (Naja naja atra) venom].

Potency of sixty antitoxic unit was reached after two immunizations in 2-week intervals of rabbits and horses with 10-25 mg Taiwan cobra (Naja naja atra) venom which was detoxified by 0.125% glutaraldehyde. Now this procedure has become a routine antivenine-producing method by which snake bivalent neurotropic antivenine is produced. The stability test showed that Taiwan cobra toxoid kept at 37 degrees C for 40 days, the antigenicity increased by 24% and toxicity decreased by 10% as compared to the toxoid maintained at 4 degrees C.

Animals↗
PubMed1989

Glucose-regulated protein (GRP94 and GRP78) genes share common regulatory domains and are coordinately regulated by common trans-acting factors.

We isolated the promoter of the human gene encoding the 94,000-dalton glucose-regulated protein (GRP94). The 5'-flanking region important for its expression was identified by deletion analysis. Comparison of the promoters of the genes for GRP78 and GRP94 derived from human, rat, and chicken cells revealed a common domain of 28 base pairs within the putative regulatory regions of both genes. This domain has been shown to interact with protein factors in the promoter of the gene for GRP78. Since the genes for GRP94 and GRP78 are transcriptionally regulated with similar kinetics under a variety of stress conditions, we are interested in examining the possible mechanisms for their coordinated expression. Through in vitro and in vivo competition assays, we found that the protein factors which interact with the promoter of the gene for GRP94 also have affinity for the conserved domain of the promoter of the gene for GRP78. These findings suggest that the genes for GRP94 and GRP78 are coordinately regulated through common trans-acting factors which recognize a common regulatory domain of glucose-regulated protein gene promoters.

Amino Acid Sequence↗
PubMed1989

Postural effect on gas exchange in patients with unilateral pleural effusions.

The effect of body position (right and left lateral decubitus positions) on arterial oxygen tension (PaO2) and the relationship between this postural effect on gas exchange and pulmonary function were evaluated in 21 patients who had unilateral pleural effusions without roentgenographic and bronchoscopic evidence of bronchopulmonary disorders. Our results indicated that a positional influence on gas exchange existed in these patients. We failed to find a consistent relationship between the size of effusion estimated by chest roentgenogram and alterations in PaO2 during different positions. Postural change did affect gas exchange in the patients with unilateral pleural effusions and this postural effect on gas exchange was highly correlated with their FEV1 and FVC. This may be of clinical significance in managing such patients.

Adult↗
PubMed1989

Purification and characterization of neuraminidase from Clostridium perfringens.

Neuraminidase (EC 3.2.1.18) has been purified from the culture medium of Clostridium perfringens ATCC 10543, through steps of gel filtration on Sephadex G-75 column, DEAE-cellulose DE 23 anion exchange chromatography, and isochromatofocusing. A homogeneous enzyme was obtained with a 7552-fold increase in specific activity to 295 units/mg protein. The yield was about 25%. The enzyme consists of a single polypeptide with a molecular weight of 69,000 as determined by SDS-polyacrylamide gel electrophoresis. Kinetic studies showed that Km is 1.5 mM for sialyllactose and Vmax is 0.41 mumole/min/ml at the enzyme concentration of 0.14 microgram/ml. The enzyme is stable at pH 5.2-8.0 with an optimal pH of 6.0. A concentrated solution of the purified enzyme was stable over one year at 4 degrees C. The purified enzyme hydrolyzed human alpha 1-acid glycoprotein completely; thus, it can be used in the clinical assay of N-acetylneuraminic acid in the serum.

Clostridium perfringens↗
PubMed1989

Prostatic cyst: report of 2 cases.

Prostatic cysts are rarely reported in the literature, however, their existence is not so rare as one may think. Two cases of prostatic cyst were found among 400 patients being examined by transrectal ultrasonography. The clinical manifestations of a cyst ranged from totally asymptomatic to urinary retention depending on cyst size and location. The diagnosis was attained by rectal examination, panendoscopy, cystourethrography and transrectal ultrasonography. The first case received an open prostatectomy and the second case was managed by puncture of a cyst.

Adult↗
PubMed1989

The role of fiberoptic bronchoscopy in evaluating the causes of pleural effusions.

To evaluate the diagnostic merit of fiberoptic bronchoscopy in pleural effusions, we performed fiberoptic bronchoscopy in addition to thoracocentesis and closed pleural biopsy in 140 patients who were admitted for diagnostic investigation of the causes of pleural effusions. The patients were divided into subgroups based on clinical features and roentgenographic findings of chest x-ray films. In 39 patients, the pleural effusions were due to various nonneoplastic disorders and in 95 patients it was caused by malignancy. In six patients, the causes of the pleural effusions remained undetermined. A final diagnosis was made by pleural examination in 68 patients, by fiberoptic bronchoscopy in 58 patients, and by either one or both in 100 patients. In 82 patients who had no hemoptysis, a final diagnosis was made by pleural examination in 57 cases and by fiberoptic bronchoscopy in 11 cases only. The diagnostic yield of fiberoptic bronchoscopy (47/58) was superior to that of pleural examination (11/58) in 58 patients presenting with hemoptysis. In 74 patients who had pleural effusions as the sole roentgenographic abnormality, the final entity was established by pleural examination in 45 and by fiberoptic bronchoscopy in 12. The diagnostic merit of fiberoptic bronchoscopy was significantly higher in 59 patients who had concurrent pulmonary abnormalities on their chest roentgenograms. A final diagnosis was made in 43 cases by fiberoptic bronchoscopy in comparison with 21 cases by pleural examination. For patients with unknown pleural effusions, fiberoptic bronchoscopy was more likely to yield a diagnosis than thoracocentesis with closed pleural biopsy in those who had hemoptysis or pulmonary abnormality on chest x-ray films, whereas the reverse applied when these features were absent.

Adult↗
PubMed1989

Retrospective analysis of 97 patients with infective endocarditis seen over the past 8 years.

The medical records of 97 consecutive patients (101 episodes) of infective endocarditis seen from January 1979 through January 1987 were reviewed. Only 30% of the patients were over 50 years of age and the majority (69%) of infecting organisms were streptococci (mainly of the viridans group), which were similar to those reported from the West in the early antibiotic era. Pseudomonas organisms and enterococci accounted for 6% and 5%, respectively. Fungal infections were noted in 2 patients. There was a high incidence (38%) of predisposing rheumatic valvular disease; approximately half of these patients had prosthetic valve infections. Mitral valve prolapse was also an important predisposing disease (11%). One-third (34%) of the patients had febrile illness for longer than 8 weeks before the diagnosis was established. The hospital morality rate was 22%; cerebral embolism and ruptured mycotic aneurysm, congestive heart failure, and sudden death were the major causes of death. Echocardiography disclosed vegetations on the cardiac valves and preexisting lesions in 75% of the episodes. Early recognition and proper treatment should be the focus of efforts to reduce mortality from infective endocarditis.

Adolescent↗
PubMed1989

Effects of antibiotic combinations on methicillin-resistant Staphylococcus aureus in vitro.

Methicillin-resistant Staphylococcus aureus (MRSA) infection has become an important infectious disease problem. Vancomycin is the only antimicrobial agent documented to be effective in the treatment of MRSA infection. Under vancomycin treatment there is still a moderate percentage of treatment failures, especially in severe MRSA infections. In searching for better treatment regimens, we evaluated the effects of several antibiotics in combination with vancomycin or fosfomycin against MRSA isolates by the checkerboard titration method. We found that the combinations of vancomycin with imipenem and fosfomycin with cefazolin had a synergistic effect against 97.1% and 94.3% of 70 tested strains, respectively. Rifampicin, gentamicin, cefazolin, or cefamandole in combination with vancomycin, and cefmetazole in combination with fosfomycin did not have such good results. They were synergistic against far fewer of the tested strains, 0%, 3.3%, 50.0%, 30.0% and 64.3%, respectively. For confirmation, further studies in vivo of the effectiveness are advisable. It is likely that we can improve the treatment of severe MRSA infections by those combination regimens which are highly synergistic against MRSA.

Drug Therapy, Combination↗
PubMed1989

Acanthamoeba keratitis: report of a case.

Acanthamoeba keratitis, rarely seen in Taiwan, has aroused much attention in western countries in recent years because of the increasing number of reported cases and its usually disastrous outcome. Most of the reported cases were closely associated with contact lens wearing. Others were related to a minor trauma or contacting contaminated water. We report a case of recalcitrant corneal ulcer following trauma, which is the first reported case of Acanthamoeba polyphaga keratitis proven by a special culture method and pathological examination in Taiwan. We reviewed the nature and characteristics of Acanthamoeba keratitis, and discussed the laboratory examinations such as staining techniques, culture methods, light and electron microscopic findings, and treatment for such cases.

Acanthamoeba Keratitis↗
PubMed1988

Comparison of a daily and three intermittent retreatment regimens for pulmonary tuberculosis administered under programme conditions.

One daily and 3 thrice weekly retreatment regimens given for 12 months under programme conditions were compared. The daily regimen was rifampicin and ethambutol (RE7). The three intermittent regimens also contained rifampicin and ethambutol: one of them, rifampicin and ethambutol throughout (RE3); the next one supplemented with pyrazinamide for the first 3 months (REZ3); the last one supplemented with prothionamide for the first 3 months (REPt3). The pyrazinamide containing regimen was subdivided into ordinary and high dose groups. The subjects for retreatment were those who have had, at least, more than 6 months of initial triple chemotherapy of isoniazid, PAS and streptomycin at the health centres, and failed to convert to bacteriologically negative status. Among 419 patients who were available for sensitivity tests before commencing retreatment, 393 (94.3%) were resistant to isoniazid. Six hundred and seventy-four patients (674) were allocated randomly to the regimens: 64 patients were excluded due to various pretreatment reasons and 109 did not complete 12 months of chemotherapy. There remain 501 patients who completed their retreatment. As assessed at 12 months, a bacteriologically favourable response was achieved in 68% of 135 RE7 patients, 62% of 129 RE3 patients, 74% of 132 REZ3 patients, and in 79% of 108 REPt3 patients. Adverse reactions were uncommon: 4% in RE7, 5% in RE3 and 9% in REZ3, but 32% in REPt3. Relapse rates during 2 years after termination of chemotherapy were 15% in RE7, 14% in RE3 and REZ3, and 26% in REPt3, as calculated by life table analysis.

Adolescent↗
PubMed1988

Relative effectiveness of prodrug and viscous solution approaches in maximizing the ratio of ocular to systemic absorption of topically applied timolol.

The effectiveness of the prodrug approach in maximizing the ratio of ocular to systemic absorption of topically applied timolol was compared with that based on viscous solutions. The pigmented rabbit was the experimental animal. o-Butyryl timolol, a lipophilic ester prodrug of timolol, was found to be twice as effective as hyaluronic acid and poly(vinyl alcohol) solutions in enhancing the ocular absorption of timolol. In addition, it was slightly more effective than retaining the instilled dose in the conjunctival sac for 240 min via nasolacrimal blockade. On the other hand, due to its inability to minimize contact of the instilled dose with the nasal mucosa, o-butyryl timolol was less capable than the viscous solutions in reducing systemic drug absorption. But this could be corrected by reducing the instilled solution volume from 25- to 5 microliter, resulting in a nine-fold reduction in plasma timolol levels while still providing the same amount of drug in the aqueous humor as a five times higher dose of timolol. The net result was a 15-fold improvement in the ratio of ocular to systemic drug absorption, which was also achieved upon retaining the instilled dose in the conjunctival sac for 240 min. It thus appears that the approach based on improved corneal absorption would be as effective as that based on improved retention in the conjunctival sac in maximizing the ratio of ocular to systemic drug absorption, so long as a smaller instilled dose volume of the prodrug is used.

Administration, Topical↗
PubMed1988

In vitro mechanism of inhibition of bacterial cell growth by allicin.

Diallyl thiosulfinate (allicin) is the agent found in garlic which is responsible for the antibacterial and antifungal activity of extracts of this plant. The effect of bacteriostatic concentrations of allicin (0.2 to 0.5 mM) on the growth of Salmonella typhimurium revealed a pattern of inhibition characterized by: (i) a lag of approximately 15 min between addition of allicin and onset of inhibition, (ii) a transitory inhibition phase whose duration was proportional to allicin concentration and inversely proportional to culture density, (iii) a resumed growth phase which showed a lower rate of growth than in uninhibited controls, and (iv) an entry into stationary phase at a lower culture density. Whereas DNA and protein syntheses showed a delayed and partial inhibition by allicin, inhibition of RNA synthesis was immediate and total, suggesting that this is the primary target of allicin action.

Bacterial Proteins↗
PubMed1988

Clinical role of bronchoscopy in adults with intrathoracic tuberculous lymphadenopathy.

Twenty-five adult tuberculosis patients with intrathoracic lymphadenopathy were studied. Intrathoracic tuberculous lymphadenopathy seems rare in Chinese and affects more older and female subjects. The most common symptoms were cough, followed by chills, fever and the most common physical finding was peripheral lymph node enlargement. The roentgenographic appearance of mediastinal lesions varied but often included right paratracheal involvement. Nine patients had clear lungs. Tuberculous involvement was limited to the lower lung field in seven out of 16 patients with concomitant parenchymal lesions. The remaining nine patients had pulmonary tuberculosis involving the upper lobes. Consolidation was the most common form of pulmonary lesion. A diagnosis was made on the basis of sputum examination in nine patients; however, peripheral lymph node examination yielded a higher diagnostic rate (90 percent). Endobronchial involvement was proved by bronchoscopy in 12 of 16 patients. In three instances, the final diagnosis could be documented after mediastinoscopy or exploratory thoracotomy.

Adult↗