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Biomedical subjects

T N Chau

Publications and source records attributed to T N Chau.

At least 19 recordsLinked to original sources
PubMed2006

Intestinal tuberculosis in a regional hospital in Hong Kong: a 10-year experience.

OBJECTIVE: To study the clinical and pathological characteristics of patients with intestinal tuberculosis. DESIGN: Retrospective study. SETTING: United Christian Hospital, Hong Kong. PATIENTS: Patients with intestinal tuberculosis diagnosed between January 1995 and December 2004 inclusive. RESULTS: The median age of the 13 male and 9 female patients was 53 years (range, 12-81 years). Nineteen (86%) had a definitive diagnosis of intestinal tuberculosis confirmed by the presence of caseating granulomas and/or acid-fast bacilli in histological specimens. In three (14%) the diagnosis was based on histology revealing non-caseating granulomas and a positive response to anti-tuberculous treatment. Common symptoms included abdominal pain (82%), diarrhoea (55%), weight loss (55%), and fever (45%). Three (14%) of the patients were complicated by intestinal obstruction, and another two (9%) had intestinal perforation. Four (18%) had concomitant active pulmonary tuberculosis. The most frequently involved site was the ileocaecal region, which was affected in 19 (86%) patients. Other sites included the jejunum, ascending and sigmoid colon. The diagnosis of intestinal tuberculosis was facilitated by examination of colonoscopic biopsy specimens (11 patients), and by examination of resected surgical specimens in the remainder. Two patients died from terminal malignancy. The remainder completed anti-tuberculous therapy and responded satisfactorily. CONCLUSIONS: The diagnosis of intestinal tuberculosis is difficult due to the lack of specific signs or symptoms. Colonoscopy with ileoscopy are useful tools in the search for colonic and terminal ileal tuberculosis. Surgical exploration is reserved for equivocal cases and for those who present as emergencies.

Adolescent↗
PubMed2006

Tuberculosis intestinal perforation during anti-tuberculosis treatment.

Intestinal perforation is an uncommon but potentially fatal complication of intestinal tuberculosis. We report on a 63-year-old HIV-negative man who developed terminal ileal perforation approximately 3.5 months following initiation of anti-tuberculous treatment for pulmonary tuberculosis and a concomitant tuberculous perianal abscess. Clinical and radiological improvements were initially evident following commencement of anti-tuberculous treatment, and the paradoxical response phenomenon was suspected. The patient subsequently underwent surgical resection of the affected bowel segment with primary anastomosis, and made an uneventful recovery. Anti-tuberculous medication was continued for another 12 months, and after a further 12 months there was no evidence of recurrent tuberculosis. This case illustrates that tuberculous intestinal perforation can develop during chemotherapy for tuberculosis. Prompt diagnosis and appropriate surgical treatment are essential to avoid morbidity and mortality.

Antitubercular Agents↗
PubMed2006

Oesophageal tuberculosis mimicking oesophageal carcinoma.

Tuberculous involvement of the oesophagus is rare, and is usually caused by direct spread from adjacent afflicted structures. We report an 83-year-old male patient with oesophageal tuberculosis secondary to tuberculous mediastinal lymphadenitis who presented with non-specific symptoms of anorexia and lethargy. Upper gastro-intestinal endoscopy revealed an ulcerative tumour-like lesion in the mid-oesophagus suggesting oesophageal carcinoma. Repeated endoscopic biopsies revealed a non-specific acute-on-chronic inflammation consisting of non-caseating granulomas, with no evidence of malignancy. Endoscopic ultrasonography demonstrated that the oesophageal lesion was secondary to direct extension of mediastinal lymphadenopathy. The diagnosis of tuberculosis was eventually confirmed by histological and microbiological analysis of a surgically excised cervical lymph node. The patient responded promptly to treatment with antituberculous drugs. We suggest that oesophageal tuberculosis has to be kept in mind in the differential diagnosis of oesophageal ulcerohypertrophic lesions.

Aged↗
PubMed2005

Prevention of transfusion-transmitted hepatitis E by donor-initiated self exclusion.

Safety in blood transfusion has all along been focused on blood borne viruses like HIV, hepatitis B and C. However, infective agents that are not usually transmitted through blood may also pose risk to transfusion if the donor gives blood in the early-viraemic phase. A case report of potential transfusion-transmitted hepatitis E (HEV) is described. It shows the virus can be transmissible via blood because of the presence of HEV RNA in the blood donated. Pre-donation health screening was unable to exclude this asymptomatic donor. But donor-initiated call back system which acts as an additional safety net prevented the release of the potential infective blood products.

Adult↗
PubMed2005

Clopidogrel-induced hepatotoxicity after percutaneous coronary stenting.

Clopidogrel, an adenosine diphosphate receptor blocker, is widely used as an adjunctive antiplatelet therapy in acute coronary syndrome and percutaneous coronary stenting. The occurrence of hepatotoxicity is rare. We describe the occurrence of symptomatic liver disease in a 74-year-old man 5 weeks following commencement of therapy with clopidogrel. The reported cases of clopidogrel-induced hepatotoxicity are reviewed and the clinical significance of this event are discussed.

Aged↗
PubMed2002

Occurrence of hepatitis E virus IgM, low avidity IgG serum antibodies, and viremia in sporadic cases of non-A, -B, and -C acute hepatitis.

Serum samples were taken from 57 patients with sporadic non-A, -B, and -C (Non A, B, C) acute hepatitis at different times after onset of the disease and tested for the presence of the hepatitis E virus (HEV) RNA, IgM, and low avidity IgG antibodies. The viral antibodies were detected using two ELISA. One assay (GL) was produced using a mixture of recombinant peptides specified by ORF2 and ORF3 of the viral genome. The other was produced with an ORF2 specified peptide, pE2. The latter occurs naturally as homodimer, it is recognized strongly in its dimeric form by human sera and, in the primate model, it confers protection against experimental HEV infection. Nineteen samples were positive for one or more of these acute markers of HEV infection, 14 of which were acute sera with elevated ALT levels and 5 were convalescent sera with normal ALT level. The results showed that icteric phase of sporadic hepatitis lasts for about 17 days and it coincides with a period when viremia is subsiding as HEV antibodies are developing. Viremia was intermittent and all but one of the 5 instances were confined to the icteric phase with elevated ALT levels. On two of these occasions, viremia preceded detection of HEV antibody, on another 2 occasions it was concurrent with the detection of pE2 specific IgM and/or low avidity IgG and only in one case of protracted viremia was the viral genome detected concurrently with avid pE2 IgG antibody. Ten (71%) of the 14 acute sera were reactive for pE2 IgM, eight (57%) were reactive for low avidity pE2 IgG, and six (43%) for the GL IgM. The sensitivity for the diagnosis of acute hepatitis E may be increased to 87% by combining pE2 IgM and viremia. GL IgM was detected later, but persisted for a longer period of time than the pE2 antibodies, and it was the only acute antibody detected in the convalescent sera.

Acute Disease↗
PubMed2001

Promotion of motoneuron survival and branching in rapsyn-deficient mice.

Inhibition of programmed cell death of motoneurons during embryonic development requires the presence of their target muscle and coincides with the initial stages of synaptogenesis. To evaluate the role of synapse formation on motoneuron survival during embryonic development, we counted the number of motoneurons in rapsyn-deficient mice. Rapsyn is a 43 kDa protein needed for the formation of postsynaptic specialisations at vertebrate neuromuscular synapses. Here we show that the rapsyn-deficient mice have a significant increase in the number of motoneurons in the brachial lateral motor column during the period of naturally occurring programmed cell death compared to their wild-type littermates. In addition, we observed an increase in intramuscular axonal branching in the rapsyn-deficient diaphragms compared to their wild-type littermates at embryonic day 18.5. These results suggest that deficits in the formation of the postsynaptic specialisation at the neuromuscular synapse, brought about by the absence of rapsyn, are sufficient to induce increases in both axonal branching and the survival of the innervating motoneuron. Moreover, these results support the idea that skeletal muscle activity through effective synaptic transmission and intramuscular axonal branching are major mechanisms that regulate motoneuron survival during development.

Animals↗
PubMed2001

Conformational antigenic determinants generated by interactions between a bacterially expressed recombinant peptide of the hepatitis E virus structural protein.

A 23 kDa peptide locating to amino acid residues 394 to 604 of the major Hepatitis E Virus (HEV) structural protein was expressed in E. coli. This peptide was found to interact naturally with one another to form homodimers and it was recognized strongly and commonly in its dimeric form by HEV reactive human sera. The antigenic activity associated with the dimeric form was abrogated when the dimer was dissociated into monomer and the activity was reconstituted after the monomer was re-associated into dimer again. The dimeric form of the peptide elicited a vigorous antibody response in experimental animals and the resulting antisera were found to cross-react against HEV, effecting an efficient immune capture of the virus. These results attributed the antigenic activity associated with the dimeric form of the peptide to conformational antigenic determinants generated as a result of interaction between the peptide molecules. It is suggested that some of these antigenic determinants may be expressed by the HEV capsid and raised the possibility of this bacterially expressed peptide as an HEV vaccine candidate.

Animals↗
PubMed2001

Histological patterns of rejection using oral microemulsified cyclosporine and tacrolimus (FK506) as monotherapy induction after orthotopic liver transplantation.

BACKGROUND/AIMS: We describe the histological patterns of rejection in liver transplant recipients using induction therapies with cyclosporine and tacrolimus monotherapy compared with standard triple therapy as historical control. METHODS: Patients formed part of the initial cohort in an open-labelled, randomised pilot study and were selected consecutively if they had histological rejection and no other confounding diagnoses. There were 13 patients in the cyclosporine monotherapy group (CsA), 11 in the tacrolimus monotherapy group and 13 in the triple therapy group (CAP). The histology of liver biopsies was reassessed blindly and the severity of rejection was recorded. RESULTS: The total Royal Free Hospital (RFH) rejection scores as well as other histological features (zone 3 haemorrhage, apoptosis in zones 1 and 3, steatosis, cholestasis, nuclear vacuolation, lymphoblasts and ballooning) were comparable in the three groups. There was no difference in individual components of the histological features comprising the diagnosis of rejection, except that the portal inflammation score was significantly lower in the tacrolimus group when compared with the CsA group (p=0.04). There was no significant difference in the number of patients with moderate/severe rejection between the three groups. Overall, there was no significant increase in histological severity of rejection in the monotherapy groups. CONCLUSIONS: The results suggest that the monotherapy may be as effective as the triple therapy in the initial post-transplant phase and that no particular graft histological changes were associated with the type of treatment.

Adolescent↗
PubMed2001

Lamivudine treatment for fulminant hepatic failure due to acute exacerbation of chronic hepatitis B infection.

BACKGROUND: Exacerbation of chronic hepatitis B infection can lead to fulminant hepatic failure with a mortality of up to 90%. AIM: To evaluate the efficacy of lamivudine in the treatment of this subgroup of patients. METHODS: Twenty-four patients with exacerbation of chronic hepatitis B infection and fulminant hepatic failure were treated with lamivudine, 100 mg daily. Hepatitis A, C, D and human immunodeficiency virus co-infections and hepatocellular carcinoma were excluded. RESULTS: The median age was 53 years (range, 24-77 years) with a male predominance of 20:4. Seventeen patients were hepatitis B e antigen positive. Mean hepatitis B virus DNA was 2079 Meq/mL. Eight patients (33%) survived (group A). Thirteen patients died and three patients received liver transplantation (67%) (group B). Baseline laboratory results were comparable between the two groups, including serum albumin, bilirubin, alanine aminotransferase, prothrombin time and creatinine. Group B patients had significantly more comorbid illnesses at baseline and more complications, including sepsis and renal failure, compared with group A patients. Six out of eight survivors (75%) had full hepatitis B e antigen seroconversion, but this was not sustained in four patients. CONCLUSIONS: Lamivudine may be useful in treating patients with fulminant hepatic failure due to exacerbation of chronic hepatitis B. Hepatitis B e antigen seroconversion was less durable in this subgroup of patients and long-term therapy may be required.

Administration, Oral↗
PubMed2001

Biliary tract disease and acute non-A-E hepatitis in Hong Kong: prospective study.

OBJECTIVE: To investigate the role of biliary tract disease in patients with acute non-A-E hepatitis. DESIGN: Prospective study. SETTING: Infectious diseases unit, government hospital, Hong Kong. PATIENTS: Sixty-one consecutive patients, admitted with the diagnosis of acute hepatitis and negative hepatitis serology for hepatitis A, B, C, D, and E virus. MAIN OUTCOME MEASURES: Abdominal ultrasound and endoscopic retrograde cholangiopancreatography findings; clinical outcome. RESULTS: Ultrasonographic abnormalities indicating biliary tract disease were found in 30% (18/61) of patients. Endoscopic retrograde cholangiopancreatography performed in 78% (14/18) of patients with abnormal ultrasound finding(s) confirmed the presence of biliary tract disease. Age, sex, serum alanine aminotransferase level, and serum albumin level were independent predictors of biliary tract disease in the patients studied. CONCLUSION: Biliary tract diseases were found in 20% of patients with acute non-A-E hepatitis. Serum amylase and abdominal ultrasonography should be performed for all patients presenting with acute non-A-E hepatitis. Endoscopic retrograde cholangiopancreatography is indicated for those with apparent gallstones or abnormal biliary tract findings.

Acute Disease↗
PubMed1999

Cytomegalovirus colitis in individuals without apparent cause of immunodeficiency.

Cytomegalovirus infection is usually reported in immunocompromised patients. In this study, apparently immunocompetent patients with cytomegaloviral colitis were reviewed. Records with a diagnosis of cytomegaloviral colitis from January 1989 to June 1996 were retrieved for analysis. Ten patients were included (median age 70 yr). The major presenting symptoms were diarrhea and hematochezia. Ulceration was the main macroscopic finding. Rectal bleeding was mostly self-limiting. Three patients developed local complications (rectovaginal fistula in two; rectal stricture in one). In the two patients with rectovaginal fistula, lymphocytes subsets and proliferative response were entirely normal. In the other patient, low B lymphocyte count and low response to mitogen were demonstrated. However, the immunoglobulins were not suppressed and rectal biopsies revealed noncaseating granulomas, suggesting activated cell-mediated immunity. In conclusion, a high index of suspicion is crucial for early diagnosis of cytomegaloviral colitis in patients with bloody diarrhea, even though obvious evidence of immunodeficiency is lacking.

Aged↗
PubMed1999

Thrombopoietin concentrations are low in patients with cirrhosis and thrombocytopenia and are restored after orthotopic liver transplantation.

BACKGROUND: Thrombocytopenia in cirrhotic patients may be due to deficient production of thrombopoietin. AIMS: To determine the relation between thrombopoietin and thrombocytopenia in cirrhotic patients before and after orthotopic liver transplantation. METHODS: Thrombopoietin concentrations and platelet counts were measured in 43 cirrhotic patients and 21 normal controls and serially for 14 days after transplantation in 23/43 patients. RESULTS: 27 of the 43 patients had thrombocytopenia (platelet count less than 120 x 10(9)/l; group 1) whereas 16 patients had normal platelet count (group 2). Thrombopoietin concentrations were lower in group 1 than in group 2 (92.5 (20.3-286.3) v 226.6 (30.1-848.3) pg/ml, p=0.003) and normal controls (92.5 (20.3-286.3) v 158.3 (22.5-232.9) pg/ml, p=0.028). Post-transplantation thrombopoietin concentrations increased with a peak at day 5. The rise was significant in patients with low pretransplantation platelet count (89.1 (21.29-247.6) to 545.1 (66.2-2569) pg/ml; n=16, p=0.001) but not in those with normal platelet count (262.8 (30.1-848.3) to 315.1 (114-954.6) pg/ml; n=7, p=0.47). No correlation was found pretransplantation between spleen volume and platelet count (r=-0.11, p=0.6) or thrombopoietin concentrations (r=-0.04, p=0.8). However, pretransplantation thrombopoietin concentrations correlated with platelet count (r=0.47, p=0.0015), whereas an inverse correlation was found between peak thrombopoietin concentrations and nadir platelet count (r=-0.41 p=0. 049) post-transplantation. CONCLUSIONS: Inadequate thrombopoietin production may contribute to cirrhotic thrombocytopenia. Thrombopoietin production is restored after liver transplantation leading to the resolution of thrombocytopenia.

Adult↗
PubMed1998

"Salvage" transjugular intrahepatic portosystemic shunts: gastric fundal compared with esophageal variceal bleeding.

BACKGROUND & AIMS: The optimal emergency treatment for gastric fundal variceal bleeding is still unclear. In this study, the efficacy of transjugular intrahepatic portosystemic stent/shunt (TIPS) in patients with uncontrolled gastric fundal vs. esophageal variceal bleeding was compared. METHODS: One hundred twelve consecutive patients with uncontrolled variceal bleeding required emergency TIPS, 84 with esophageal varices (EV group) unresponsive to endoscopic and vasoconstrictor therapy and 28 with gastric fundal varices (GV group) unresponsive to vasoconstrictor therapy. Clinical and biochemical data were retrieved, and the two groups were compared. RESULTS: Variceal bleeding was controlled in all patients after TIPS except for 1 in each group. There were no significant differences between the two groups in terms of markers of disease severity, severity of bleeding, or portal hemodynamics. During a median follow-up period of 7 months, 20 in the EV group (24%) and 8 in the GV group (29%) developed clinical rebleeding. Most early rebleeding (within 7 days after TIPS) was related to esophageal ulceration secondary to previous sclerotherapy. Rates of mortality were similar in both groups. CONCLUSIONS: These results suggest that emergency TIPS is equally effective in the immediate short-term control of gastric fundal variceal bleeding compared with esophageal variceal bleeding.

Adult↗
PubMed1998

Delayed mid-ileal perforation secondary to acute-on-chronic ischaemia after a diagnostic colonoscopy.

Perforation occurring at a remote site of the bowel after diagnostic colonoscopy is rare. A 61-year-old man presenting with bloody diarrhoea underwent colonoscopy. A dynamic ileus developed in less than 1 day, and mid-ileal perforation occurred 7 days after the procedure. It is suggested that high air pressure during colonoscopy further compromised the reduced blood flow in the mid-ileum, which had underlying chronic ischaemia, leading to perforation. Our patient constitutes the first reported case of small-bowel perforation after colonoscopy due to pre-existent ileal ischaemia.

Acute Disease↗