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Biomedical subjects

C H Chau

Publications and source records attributed to C H Chau.

At least 19 recordsLinked to original sources
PubMed2004

Laparoscopic exploration of common bile duct in difficult choledocholithiasis.

BACKGROUND: This review investigated the role played by laparoscopic exploration of the common bile duct (LECBD) in the management of difficult choledocholithiasis. METHODS: This retrospective study reviewed a prospective database of LECBD for difficult choledocholithiasis during the period 1995 to 2003. RESULTS: Of the 97 LECBDs performed in the authors' center from 1995 to 2003, 25 were performed for difficult choledocholithiasis. Difficult choledocholithiasis was defined as failure of endoscopic stone retrieval for the following reasons: access and cannulation difficulty, the difficult nature of common bile duct (CBD) stones, and the presence of endoscopic retrograde cholangiopancreatography (ERCP)-related complications. There were seven unsuccessful cannulations because of previous gastrectomy (n = 5) and periampullary diverticulum (n = 2). Among the 18 patients with failed endoscopic extraction, there were 10 impacted stones, 2 incomplete stone clearances after multiple attempts, 2 type 2 Mirizzi syndromes, 1 proximal stent migration, 1 repeated post-ERCP pancreatitis, 1 situs inversus, and 1 stricture at the distal common bile duct. There were 14 male and 11 female patients with a mean age of 67.8 +/- 15 years. Initial presentations included cholangitis (n = 14, 56%), biliary colic (n = 3, 12%), jaundice/deranged liver function ( n = 5, 20%), cholecystitis (n = 2, 8%), and pancreatitis (n = 1, 4%). Regarding the approach for LECBD, there were 2 transcystic duct explorations and 23 choledochotomies. The mean operative time was 149.4 +/- 49.3 min, and there were three conversions (12%). The stone clearance rate was 100%, and no recurrence was detected during a mean follow-up period of 16.8 months. Five complications were encountered, which included bile leak (3 patients) and wound infection (2 patients). When the results were compared with the remaining 72 LECBDs for nondifficult stones during the same period, the complication rate, conversion rate, and rate of residual stones were similar despite a longer operation time (149.4 +/- 49.4 min vs 121.6 +/- 50.5 min). CONCLUSION: When ERCP is impossible or stone retrieval is incomplete, LECBD is the solution to difficult CBD stones.

Adult↗
PubMed2004

Routine use of laparoscopic repair for perforated peptic ulcer.

BACKGROUND: Laparoscopic repair of perforated peptic ulcer was reported in 1990 but has not gained wide acceptance. The aim of this study was to evaluate the safety and efficacy of laparoscopic repair for perforated peptic ulcer in routine clinical practice. METHODS: This was a prospective analysis of 172 patients who underwent laparoscopic repair of a perforated peptic ulcer between July 1997 and June 2003. RESULTS: One hundred and seventy-two patients of mean age 54 (range 14-93) years had perforated peptic ulcer diagnosed by laparoscopy. There were 172 duodenal ulcers, 22 prepyloric and 13 non-juxtapyloric gastric ulcers. One hundred and sixty-five patients underwent omental patch closure of perforations; there were six Pólya gastrectomies and one ulcerectomy. Thirty-seven patients (21.5 per cent) required conversion to laparotomy. The mean operating time was 64.8 (range 14-180) min. The median postoperative requirement for intramuscular pethidine was one dose. The median postoperative hospital stay was 6 days. Complications occurred in 28 patients (16.3 per cent) resulting in three reoperations. Six patients with intra-abdominal collections were managed by percutaneous drainage. Two patients who underwent conversion developed a wound infection. Fourteen patients (8.1 per cent) died, 11 of whom were American Society of Anesthesiologists grade III and IV. CONCLUSION: Laparoscopic repair of perforated peptic ulcer is a safe emergency procedure in routine clinical practice for patients with perforated pyloroduodenal ulcer.

Adolescent↗
PubMed2003

Chondroitinase ABC enhances axonal regrowth through Schwann cell-seeded guidance channels after spinal cord injury.

Grafting of Schwann cell-seeded channels into hemisected adult rat thoracic spinal cords has been tested as a strategy to bridge the injured cord. Despite success in guiding axonal growth into the graft, regeneration across the distal graft-host interface into the host spinal cord was limited. We hypothesized that chondroitin sulfate (CS) glycoforms deposited at the gliotic front of the interface constitute a molecular barrier to axonal growth into the host cord. Because CS glycoforms deposited by purified astrocytes in vitro were removable by digestion with chondroitinase ABC, we attempted to achieve likewise by infusion of the enzyme to the host side of the interface. By 1 month post-treatment, significant numbers of regenerating axons crossed an interface that was subdued in macrophage/microglia reaction and decreased in CS-immunopositivity. The axons extended as far into the caudal cord as 5 mm, in contrast to nil in vehicle-infused controls. Fascicular organizations of axon-Schwann cell units within the regenerated tissue cable were better-preserved in enzyme-treated cords than in vehicle-infused controls. We conclude that CS glycoforms deposited during gliosis at the distal graft-host interface could be cleared by the in vivo action of chondroitinase ABC to improve prospects of axonal regeneration into the host spinal cord.

Animals↗
PubMed2003

Smoking and tuberculosis in Hong Kong.

OBJECTIVE: To study the relationship between smoking and tuberculosis in Hong Kong. METHOD: Indirect sex and age adjustment was used to compare the prevalence of ever smokers between a sample of 851 patients from the 1996 tuberculosis notification registry and the general population. The clinical characteristics of smokers and non-smokers were compared by stratified univariate analysis and multiple logistic regression. RESULTS: Tuberculosis patients were more likely to have smoked than population controls. The respective odds ratios for ever smoking between tuberculosis patients and population controls were 2.44 and 2.08 for males and females aged 16-64 (Mantel-Haenszel weighted OR = 2.40, P < 0.001), and 2.09 and 2.83 for males and females aged > or = 65 (Mantel-Haenszel weighted odds ratio = 2.19, P < 0.001). Male sex, age > or = 65, working at onset of illness, regular alcohol use, drug abuse and absence of contact history were associated with ever smokers (all P < 0.05). Ever smokers were more likely to have cough (OR 1.69), dyspnoea (OR 1.84), upper zone involvement (OR 1.67), cavity (OR 1.76), miliary lung involvement (OR 2.77), positive sputum culture (OR 1.43), but less isolated extrathoracic involvement (OR 0.31), even after controlling for the confounding background variables (all P < 0.05). CONCLUSION: There was a consistent association between smoking and tuberculosis. More aggressive lung involvement was also found among ever smokers.

Adolescent↗
PubMed2002

Laparoscopic cholecystectomy versus open cholecystectomy in elderly patients with acute cholecystitis: retrospective study.

OBJECTIVE: To study the safety and efficacy of laparoscopic cholecystectomy for acute cholecystitis in elderly patients by comparing the results with open cholecystectomy. DESIGN: Retrospective study. SETTING: Regional hospital, Hong Kong. SUBJECTS AND METHODS: Patients aged 75 years or older undergoing laparoscopic cholecystectomy for acute cholecystitis between January 1994 and December 1999 were selected from the database. The comparison group comprised patients from the same age-group who underwent open cholecystectomy for acute cholecystitis during the same period. MAIN OUTCOME MEASURES: Operating time, hospital stay, morbidity, and mortality. RESULTS. Thirty-one patients underwent laparoscopic surgery and 42 had open surgery. The demographic data and co-morbidities were comparable between the two groups. The postoperative hospital stay was significantly shorter for patients undergoing laparoscopy (P=0.03). The overall morbidity rate was significantly lower for patients undergoing laparoscopy (P<0.05). There was, however, no statistical significant difference in the mortality rate. There was no major bile duct injury for patients in either group. CONCLUSION: Laparoscopic cholecystectomy is a safe procedure for acute cholecystitis in elderly patients, resulting in fewer complications and shorter hospital stay than open cholecystectomy.

Acute Disease↗
PubMed2001

Comparison of MB/BacT system and agar proportion method in drug susceptibility testing of Mycobacterium tuberculosis.

The drug susceptibilities of 105 isolates/strains of Mycobacterium tuberculosis (101 clinical isolates and four control strains from the American Type Culture Collection) were assessed by the MB/BacT system and conventional agar proportion method. The agreement rates between the two methods were 99.0% for streptomycin, 95.2% for isoniazid and 100% for rifampin. The mean times to detection for drug-resistant isolates were 4.7 days (range: 2.5-13.7 days) using the MB/BacT system and 14.8 days (range: 14-21 days) using the agar proportion method. For drug-susceptible isolates, the times to detection were 10.8 days (mean) and 21 days respectively. Thus, these data have demonstrated that the automated, non-radiometric MB/BacT system is an efficient, accurate and reliable method for assessing drug susceptibilities of M. tuberculosis compared with the conventional agar proportion method.

Antibiotics, Antitubercular↗
PubMed2001

Chronic necrotizing pulmonary aspergillosis. A report of 9 cases with analysis of clinical picture, risk factors and treatment for outcome correlation.

Nine patients with chronic necrotizing pulmonary aspergillosis (CNPA) were analyzed retrospectively. Eight cases had been treated with itraconazole. Four patients had received intravenous amphotericin B (AMB), three sequentially with itraconazole and one as monotherapy. Three patients died after 1, 2 and 24 weeks of therapy. Six responded to therapy and survived 3 to 58 months after treatment. Only the total number of risk factors was found to be statistically significant in relation to a fatal outcome. The mean number of risk factors was 5.33 for fatal cases compared to 2.83 for treatment responders. The presence of five or more risk factors and two individual risk factors, hypoalbuminemia less than 27 g/L and history of dual pulmonary mycobacterioses, were 100% predictive of mortality in our patients. The overall clinical picture of fatal CNPA cases resembles closely that of acute invasive pulmonary aspergillosis in severely immunocompromised subjects.

Aged↗
PubMed2000

Laparoscopic pancreas-preserving total gastrectomy for proximal gastric cancer. A case and technical report.

Although total gastrectomy with distal pancreatectomy has been the standard surgical treatment for advanced gastric cancer, this procedure is frequently complicated by leakage of pancreatic juice and postoperative diabetes mellitus. We present the case of a 74-year-old woman with proximal gastric cancer who underwent a laparoscopic modification of an open pancreas-preserving procedure first described by Maruyama et al. in 1995. With this novel technique, there is no pancreatic leakage, and at 12-month follow-up our patient remains free of diabetes. Herein we give the details of our new method and offer some caveats for its performance.

Aged↗
PubMed2000

Outcomes of patients with multidrug-resistant pulmonary tuberculosis treated with ofloxacin/levofloxacin-containing regimens.

OBJECTIVE: To analyze outcomes of patients with multidrug-resistant tuberculosis (MDR-TB) treated with ofloxacin/levofloxacin-containing regimens. MATERIALS AND METHODS: From February 1990 through June 1997, 63 MDR-TB patients (with bacillary resistance to at least isoniazid and rifampin in vitro) were analyzed retrospectively. Twenty-two patients (34.9%) had had no previous antituberculosis chemotherapy. Each patient received either ofloxacin (53) or levofloxacin (10) even though 13 patients had bacilli resistant to ofloxacin in vitro. The other accompanying drugs mainly included aminoglycosides, cycloserine, ethionamide/prothionamide, and pyrazinamide. Sputum smear and culture examinations for acid-fast bacilli (AFB) were performed monthly for the initial 6 months and then at 2- to 3-month intervals until the end of treatment. Comparison was made between clinical successes and failures using univariate and multiple logistic regression analyses for the following variables: age, sex, presence of cavitation, extent of disease, sputum smear positivity, in vitro resistance to ofloxacin, in vitro resistance to streptomycin and/or ethambutol, treatment adherence, and the number of drugs per regimen. RESULTS: Fifty-one patients (81.0%) were cured, nine patients (14.3%) failed, and three patients (4.7%) died. For the entire group, the mean duration of treatment was 14.0 months, and the mean number of drugs was 4.7. Mean durations of chemotherapy in successful and failed patients were 14.5 and 14.2 months, respectively. Mean time for sputum smear and culture conversions were 1.7 and 2.1 months, respectively. Only cavitation, resistance to ofloxacin, and poor adherence were found to be variables independently associated with adverse outcomes (p < 0.05; odds ratios = 15.9, 13.5, 12.8, respectively). Negative sputum cultures after 2 and 3 months of therapy were 100% predictive of cure. Positive sputum cultures after 2 and 3 months were 52.3% and 84.6% predictive of failure, respectively. One patient (2.1%) relapsed after apparent cure. Twenty-five patients experienced adverse drug reactions, but only 12 of them needed drug modifications. CONCLUSION: Most MDR-TB patients can be treated effectively with ofloxacin/levofloxacin-containing regimens. Presence of cavitation, resistance to ofloxacin in vitro, and poor adherence to therapy portend treatment failure. Monitoring monthly sputum culture for AFB in the initial months of chemotherapy helps predict clinical outcomes.

Adult↗
PubMed1999

Heparan sulphates upregulate regeneration of transected sciatic nerves of adult guinea-pigs.

The increased content of soluble glycosaminoglycan-containing forms in sciatic nerves during recovery from crush injury [Shum & Chau (1996) J. Neurosci. Res., 46, 465] suggests that the glycosaminoglycans modulate the environment for post-traumatic tissue remodelling and axonal regrowth. To test this, defined amounts of soluble heparan sulphates from bovine kidney or guinea-pig nerve were introduced into the regenerating environment via silicone conduits that bridged 8-mm gaps of transected sciatic nerves of adult guinea-pigs. Controls were bridged using the phosphate-buffered saline (PBS) vehicle or a chondroition sulphate preparation from whale cartilage. After timed periods of recovery, the animals were assessed for electromyographic signals at the target gastrocnemius muscle to determine the conduction velocity across the bridged nerve. Sections of the bridge were also histologically examined for nerve fibres. Transected sciatic nerves bridged with heparan sulphates or chondroitin sulphate showed earlier stimulated myelination of axons (week 5-6) than PBS-bridged nerves (week 9). Initial electromyographic indication of reconnection with the target was at week 9 post-transection. In the course of 20 weeks, transected sections of the bridge indicated similar numbers of unmyelinated axons irrespective of bridge material, but distinctly higher numbers of myelinated axons in heparan sulphate-bridged nerves than either PBS- or chondroitin sulphate-bridged nerves. At the end of the same period, heparan sulphate-bridged nerves resumed normal conduction velocities, but both PBS- and chondroitin sulphate-bridged nerves remained at 50% of that of the intact contralateral nerves. These results are the first to demonstrate that supplementation of soluble heparan sulphate to the fluid regenerative neural environment can restore functional, axonal reconnection of the severed nerve with the target muscle.

Animals↗