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Biomedical subjects

S H Lam

Publications and source records attributed to S H Lam.

16 recordsLinked to original sources
PubMed2006

Predictors of peptic ulcer rebleeding after scheduled second endoscopy: clinical or endoscopic factors?

BACKGROUND AND STUDY AIMS: In a previous study we demonstrated the efficacy of second-look endoscopy with therapy within 16 - 24 hours after index endoscopy in reducing major recurrent peptic ulcer bleeding. In this study, we sought to identify factors that might predict further rebleeding after this scheduled second-look endoscopy. PATIENTS AND METHODS: We studied 249 patients (181 men, 68 women) with acute bleeding peptic ulcers who were treated at the United Christian Hospital, Hong Kong from 1999 to 2002 and who underwent a scheduled second endoscopy. Those patients who developed rebleeding after the second endoscopy were evaluated, and possible predictive factors for rebleeding were analyzed using a logistic regression model. RESULTS: Of the 249 patients who underwent scheduled second-look endoscopy, 17 patients (6.8 %) developed rebleeding: seven of these patients were treated by another endoscopic therapy; ten patients required surgery. The overall mortality rate was 3.1 %. A logistic regression analysis performed on the possible predictive factors for rebleeding found that the following factors were associated with a significant risk of further rebleeding after scheduled second endoscopy: American Society of Anesthesiologists (ASA) grade III or grade IV status (odds ratio 3.81, 95 % CI 1.27 - 11.44), ulcer size greater than 1.0 cm (odds ratio 4.69, 95 % CI 1.60 - 13.80), and a finding of persistent stigmata of recent hemorrhage at the scheduled second endoscopy (odds ratio 6.65, 95 % CI 2.11 - 20.98). CONCLUSIONS: Endoscopic factors, including large ulcer size and the persistence of endoscopic stigmata of recent hemorrhage are important predictors for recurrent bleeding after scheduled second endoscopy.

Aged↗
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↗
PubMed2005

Effects of thyroid hormone on the development of immune system in zebrafish.

Effects of thyroxine (T4) and methimazole (MMI) on the development of the zebrafish immune system were investigated using continuous immersion treatment experiments. The effects of the treatments on thymus development were determined using computer-aided thymus morphometric analyses on in situ hybridization serial sections of the thymus while the effects on immune-related gene expression levels were monitored using quantitative real-time PCR. The findings indicate that thymus development and thymopoiesis, as indicated by thymus size, thymus Rag-1-positive region, and TCRAC expression level, were affected by T4 and MMI-treatments. With the exception of Ikaros, MMI-treated fish has lower immune-related gene expression levels, although it is not certain whether the effect resulted indirectly from the concomitant growth-retardation and/or directly from an effect on lymphopoiesis itself. The findings were comparable with those in mammalian system, thus providing the first evidence that the thyroid relationship with thymus development and lymphopoiesis is likely to be conserved from fish to higher vertebrates. It suggests the possibility of using zebrafish as a model system to investigate the molecular mechanisms involved in thyroid hormone-dependent disorders in the immune system.

Animals↗
PubMed2005

Recurrent variceal bleeding in a young woman.

Congenital hepatic fibrosis is an uncommon fibrocystic disorder affecting the intrahepatic bile ducts. It has autosomal recessive inheritance. The main consequence of this condition is portal hypertension and it is often misdiagnosed as cirrhosis. Patients with congenital hepatic fibrosis usually present during childhood or early adolescence with oesophageal variceal bleeding. Portosystemic shunt surgery is the treatment of choice for these patients as the risk of postoperative hepatic encephalopathy is low. We report a patient with congenital hepatic fibrosis who presented with oesophageal variceal bleeding at the age of 16 years, initially misdiagnosed as having cryptogenic liver cirrhosis. The patient experienced two further episodes of oesophageal variceal bleeding in subsequent years. She eventually underwent portosystemic shunt surgery. One year after the operation, the shunt remained patent on Doppler ultrasonography, and there had been no further episodes of variceal bleeding post-surgery.

Adult↗
PubMed2005

Surgical management of substernal goitre: local experience.

OBJECTIVES: To examine the presentation, workup, and surgical complications of substernal goitre. DESIGN: Retrospective study. SETTING: Regional hospital, Hong Kong. PATIENTS: Twenty-four mostly elderly patients (mean age, 60.1 years) who underwent thyroidectomy for substernal goitres between 2000 and 2003 (substernal goitres were defined as those having either a caudal mass transgressing the fourth thoracic vertebra or having more than 50% of their overall mass residing within the thorax). MAIN OUTCOME MEASURES: Symptoms, histopathological diagnoses, morbidities, and complications. RESULTS: Dyspnoea was the most common symptom (n=8, 33%). Three (12.5%) patients presented with acute airway obstruction; however, 13 (54.2%) were asymptomatic apart from the presence of cervical masses. Computed tomographic scans were performed on all but two patients. Malignancy was present in 12.6% of patients, or 16.8% if occult papillary carcinoma is included. Partial or full sternotomies were performed in two (8.3%) patients. Complications included recurrent laryngeal nerve injury (n=1, 2.7% of nerves at risk), transient hypoparathyroidism (n=2, 13.3% of patients at risk), haematoma (n=1, 2.7%), pneumonia (n=1, 2.7%), and wound infection (n=1, 2.7%). There was no operative mortality or permanent hypoparathyroidism. The complication rate was significantly lower in the asymptomatic patients (P=0.033 by Fisher's exact test); clinicopathological parameters were otherwise statistically comparable between the two groups. CONCLUSIONS: There is rarely any mortality in thyroidectomy for substernal goitre, and the morbidity is also very low, especially in asymptomatic patients. In the absence of contra-indications, substernal goitre should be treated with early surgery rather than having it run the risk of acute airway distress or cancer.

Adult↗
PubMed2004

Development and maturation of the immune system in zebrafish, Danio rerio: a gene expression profiling, in situ hybridization and immunological study.

The development and maturation of the immune system in zebrafish was investigated using immune-related gene expression profiling by quantitative real-time polymerase chain reaction, in situ hybridization (ISH), immunoglobulin (Ig) detection by immuno-affinity purification and Western blotting as well as immersion immunization experiments. Ikaros expression was first detected at 1 day post-fertilization (dpf) and thereafter increased gradually to more than two-fold between 28 and 42dpf before decreasing to less than the initial 1dpf expression level in adult fish (aged 105dpf). Recombination activating gene-1 (Rag-1) expression levels increased rapidly (by 10-fold) between 3 and 17dpf, reaching a maximum between 21 and 28dpf before decreasing gradually. However, in adult fish aged 105dpf, the expression level of Rag-1 had dropped markedly, and was equivalent to the expression level at 3dpf. T-cell receptor alpha constant region and immunoglobulin light chain constant region (IgLC) isotype-1, 2 and 3 mRNAs were detected at low levels by 3dpf and their expression levels increased steadily to the adult range between 4 and 6 weeks post-fertilization (wpf). Using tissue-section ISH, Rag-1 expression was detected in head kidney by 2wpf while IgLC-1, 2 and 3 were detected in the head kidney and the thymus by 3wpf onwards. Secreted Ig was only detectable using immuno-affinity purification and Western blotting by 4wpf. Humoral response to T-independent antigen (formalin-killed Aeromonas hydrophila) and T-dependent antigen (human gamma globulin) was observed in zebrafish immunized at 4 and 6wpf, respectively, indicating that immunocompetence was achieved. The findings reveal that the zebrafish immune system is morphologically and functionally mature by 4-6wpf.

Animals↗
PubMed2004

Tracheostomy in a patient with severe acute respiratory syndrome.

The coronavirus which causes severe acute respiratory syndrome (SARS) is a virulent and highly contagious organism. Of the 1755 SARS patients in Hong Kong, over 400 were healthcare workers. Meticulous attention to infection control and teamwork are essential to minimize cross-contamination and prevent staff from contracting the illness. These points are especially pertinent when anaesthetizing SARS patients for high-risk procedures such as tracheostomy. We describe the management of such a case.

Cross Infection↗
PubMed2003

Effect of scheduled second therapeutic endoscopy on peptic ulcer rebleeding: a prospective randomised trial.

AIM: Recurrent bleeding after initial haemostasis is an important factor that directly relates to the outcome in the management of peptic ulcer bleeding. Conflicting reports have been published concerning the effectiveness of scheduled second therapeutic endoscopy on ulcer rebleeding. We investigate the use of scheduled second endoscopy with appropriate therapy on peptic ulcer rebleeding. METHODS: From August 1999 to January 2001, we prospectively randomised patients who had endoscopically confirmed bleeding peptic ulcer with stigmata of acute bleeding, visible vessel, or adherent clot into two groups. Endoscopic therapy was standardised to initial epinephrine injection and subsequent heater probe application. The study group (n = 100) received scheduled second endoscopy 16-24 hours after initial haemostasis, and further therapy was applied if endoscopic stigmata persisted, as above. The control group (n = 94) were observed closely. Those patients that developed rebleeding in either group underwent operation if further endoscopic therapy failed. Outcome measures included ulcer rebleeding, transfusion, duration of stay, and mortality. RESULTS: After initial endoscopic haemostasis, 194 eligible patients were randomised into two groups. Thirteen patients in the control group developed recurrent bleeding within 30 days while five patients in the study group sustained recurrent bleeding (p = 0.0314) (relative risks 0.33, 95% confidence interval 0.1-0.96). The number of patients that required surgery for recurrent bleeding was six in the control group and one in the study group (p = 0.05). There was no difference in duration of hospital stay, transfusion, or mortality between the two groups. CONCLUSIONS: A scheduled repeat endoscopy with appropriate therapy 16-24 hours after initial endoscopic haemostasis reduces the number of cases of recurrent bleeding.

Aged↗
PubMed2002

Morphologic transformation of the thymus in developing zebrafish.

The morphologic transformation of the developing zebrafish thymus from 1 week postfertilization (wpf) to 15 wpf is described. The thymus overall morphology changed from a small pouch-like shape at 1 wpf to a conical shape between 2 and 3 wpf before acquiring a more complex shape from 4 wpf onward. Rapid growth rate along the lateral axis at the region near the pharyngeal epithelium occurred between 1 and 2 wpf, whereas rapid growth rate along the dorsal-ventral axis occurred between 3 and 6 wpf. Expansion of thymocyte population beginning from 1 wpf became more evident by 2 to 3 wpf, as indicated by the apparent increase of different sizes of lymphocytes, recombination activating gene-1 (rag-1), and T-cell antigen receptor alpha chain constant region (TCRAC) -positive cells. Tissue section in situ hybridization (ISH) analysis with rag-1 probe reveals that cortex-medullary regionalization has begun between 1 and 2 wpf as rag-1 expression clearly demarcated the cortex, whereas the medulla was rag-1 negative. The presence of TCRAC-positive cells in the medulla by 2-3 wpf, suggests that the thymic selection processes had begun. The zebrafish thymus is morphologically mature by 3 wpf. Early signs of thymic involution were observed in zebrafish aged 15 wpf.

Animals↗
PubMed2002

On-table cecoscopy : a novel diagnostic method in acute diverticulitis of the right colon.

PURPOSE: Controversies abound regarding the optimal surgical management in noncomplicated diverticulitis of the right colon, ranging from a conservative approach to diverticulectomy to right hemicolectomy. One of the arguments for resection is to exclude carcinoma. However, there is significant morbidity associated with resection. We aim to introduce on-table cecoscopy as a tool to improve the diagnosis of acute diverticulitis of the right colon, exclude carcinoma, and reduce the rate of resection. METHODS: From October 1999 to June 2000, five patients presented to our unit with suspected acute appendicitis. Intraoperatively, we found a colonic inflammatory mass at either the cecum or the ascending colon. The cecum and ascending colon were mobilized, and bowel clamps were applied to the ascending colon and ileum. A bronchoscope (Olympus(R) BF-P200) was introduced through the appendix stump. To achieve a good endoscopic view, a limited volume of air was introduced through the working channel. RESULTS: After on-table cecoscopy, all the patients were diagnosed as having acute nonperforated diverticulitis of the right colon. They received appendicectomy, and the diverticulitis was managed conservatively. They were treated with a course of cephalosporin and metronidazole. We performed colonoscopy four weeks later and confirmed that none of them had carcinoma of the colon. CONCLUSIONS: On-table cecoscopy is a new, safe, and effective means of diagnosing acute diverticulitis of the right colon. We can confidently exclude carcinoma and reduce the amount of colonic resection in patients with noncomplicated diverticulitis of the right colon.

Acute Disease↗
PubMed2000

A method for the automated mapping of laboratory results to LOINC.

LOINC is emerging as the standard for laboratory result names, and there is great interest in mapping legacy terms from laboratory systems to it. However, the mapping task is non-trivial, requiring significant resource commitment and a good understanding of the LOINC identifying attributes for the laboratory result names. Because the number of results in a laboratory system may range from around 500 to 2000 or more, manual, one-by-one matching, even with the aid of the RELMA matching tool provided by LOINC, is time consuming and laborious. Moreover, human variation may introduce mapping inconsistencies or errors. Through our experience mapping the results from a variety of laboratory systems to LOINC, an automated mapping method has been developed and is described in this paper. This method allows for data from the laboratory information system to be provided in a manner familiar to the submitting technician, and makes use of parsing and logic rules, combined with synonyms, attribute relationships and mapping frequency data, to perform automated matching to LOINC.

Classification↗
PubMed1999

Applying the desiderata for controlled medical vocabularies to drug information databases.

Medication history has always been an integral part of the patient's medical record. With the advent of the computerized medical record and the longitudinal clinical data repository, having the medication history has enabled the development of clinical decision support system that alerts for drug to drug interactions and drug allergies. Furthermore, medication data is increasingly being analyzed from a utilization and clinical outcomes standpoint. For these activities to occur, a controlled pharmacy vocabulary akin to a controlled medical vocabulary is essential. Drug information databases are well-established sources of information for pharmacy-related data and products. However, do they measure up as a controlled vocabulary? Recent experience reviewing drug information databases and integrating pharmacy-related information into a data dictionary in real-time clinical use at multiple health care institutions have revealed several challenges and issues. These are discussed according to Cimino's desiderata for controlled medical vocabularies.

Databases, Factual↗
PubMed1993

Implementation and evaluation of practice guidelines.

Practice guidelines for the management of deep vein thrombosis were implemented in a Problem-Oriented Patient Management System on the HELP Hospital Information System at the LDS Hospital. A hierarchical knowledge representation was used. The Problem-Oriented Patient Management System was designed to generate patient-specific guideline suggestions according to the clinical situation at the time of generation. A retrospective evaluation was used to compare the appropriateness of the generated guideline suggestions to the appropriateness of the attending physician's management decisions. A significantly higher proportion of guideline suggestions was evaluated to be appropriate, compared to the proportion of attending physician's management decisions found to be appropriate.

Evaluation Studies as Topic↗