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Biomedical subjects

C H Chui

Publications and source records attributed to C H Chui.

At least 19 recordsLinked to original sources
PubMed2006

Cervical ectopic thymus in an infant.

Cervical ectopic thymus, a common embryological anomaly detected incidentally at autopsy, is rarely described in clinical patients. About 100 cases have been described in the literature, ten percent of which occurred in neonates. We report a case of solid cervical ectopic thymus in a three-month-old male infant presenting as a neck lump and snoring at sleep. The embryopathogenesis, clinical features, diagnostic modalities and management options are discussed, together with a review of the literature.

Choristoma↗
PubMed2005

Fetus-in-fetu in the pelvis: report of a case and literature review.

INTRODUCTION: Fetus-in-fetu is an extremely rare condition in which a malformed fetus is found in the body of its twin. To our knowledge, fewer than 100 cases have been reported. Wide variations of presentation have been described, although its embryo-pathogenesis and differentiation from a teratoma have not been well established. CLINICAL PICTURE: We describe a male neonate with a fetoid-like mass in his pelvis associated with bilateral undescended testes. The mass was detected on prenatal ultrasound scans. The diagnosis of fetus-in-fetu was considered prenatally and confirmed on a computed tomography scan after birth. OUTCOME: The mass was successfully excised. Histological examination, accompanied by a review of the literature, confirmed that the mass had features consistent with a fetus-in-fetu. CONCLUSIONS: Although an extremely rare clinical entity, fetus-in-fetu can be diagnosed prior to surgery with current imaging modalities. When it arises in the retroperitoneum of a male infant, it can hinder the descent of the testes. Complete excision is curative.

Cryptorchidism↗
PubMed2004

When is a mediastinal mass critical in a child? An analysis of 29 patients.

The aims of this study were to determine the pattern of presentation of childhood mediastinal masses in our community and to identify factors associated with the development of acute airway compromise. The authors retrospectively reviewed the records of 29 consecutive patients with mediastinal masses managed at their institution between January 1995 and December 2001. Demographic data, mass characteristics, clinical presentation, and surgical procedures were recorded. Seven patients (24.1%) were asymptomatic at presentation. Eight (27.6%) were classified as having acute airway compromise at presentation. Respiratory symptoms and signs were the most common mode of presentation (58.6% and 55.2%, respectively). The most common histological diagnosis was neurogenic mass (37.9%), followed by lymphoma (24.1%). Most masses were located in the superior mediastinum (41.1%). Factors associated with the development of acute airway compromise were (1) anterior location of the mediastinal mass (P=0.019), (2) histological diagnosis of lymphoma (P=0.008), (3) symptoms and signs of superior vena cava syndrome (P=0.015 and 0.003, respectively), (4) radiological evidence of vessel compression or displacement (P=0.015), (5) pericardial effusion (P=0.015), and (6) pleural effusion (P=0.033). Clinical presentation of childhood mediastinal masses is often nonspecific or incidental. Yet they have the propensity of developing acute airway compromise, which is closely associated with superior vena cava obstruction. Such patients should be managed as a complex cardiorespiratory syndrome, termed "critical mediastinal mass syndrome", by an experienced multidisciplinary team.

Adolescent↗
PubMed2003

Childhood acute pancreatitis in a children's hospital.

OBJECTIVE: To analyse the cases of acute pancreatitis presented to a children's hospital in Singapore. METHODS: Clinical charts of all children, aged under 18 years, who presented to our hospital for the first time with pancreatitis (ICD search criteria = 577.x) between the period of 1998 and mid-2002 were reviewed. Parameters analysed included presenting features, aetiology of the acute pancreatitis, length of hospital stay, complications, treatment and outcome. RESULTS: There were 12 cases in the review period, and the attributable causes in these cases were, in descending order, trauma, drug-induced, anatomical anomalies, poisoning and idiopathic. Of interest were two patients whose pancreatitis were results of child abuse. The most common symptoms were abdominal pain (n=11) and vomiting (n=7), though only five patients localised the pain to the epigastrium. Abdominal tenderness could be elicited in all the patients. Eleven had evidence of acute pancreatitis from computerised tomography (CT) whilst the twelfth was diagnosed with ultrasonography. The peak amylase levels amongst these patients were not high, with a median of 512.5 U/L. In the acute stage, only one patient required operative intervention whilst the remainder were managed conservatively. The mean length of hospital stay was 12.41 +/- 4.54 days. The complications encountered included pseudocyst formation, ascites, hypocalcaemia, pleural effusion and coagulopathy. CONCLUSIONS: The diagnosis of acute pancreatitis in children can be difficult. This is often due to ambiguous symptoms, signs and laboratory results. CT and ultrasound are essential investigations in the diagnosis and subsequent follow-up.

Acute Disease↗
PubMed2002

Is reexcision in pediatric nonrhabdomyosarcoma soft tissue sarcoma necessary after an initial unplanned resection?

PURPOSE: The aim of this study was to determine the importance of pretreatment reexcision (PRE) of pediatric nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) after initial unplanned resection. METHODS: The authors retrospectively reviewed the records of 116 consecutive patients with surgically resected NRSTS treated at their institution between February 1978 and September 1999. Ninety-four (81.0%) patients had undergone unplanned resections before referral to their institution for further therapy. Demographic data, tumor characteristics, treatment administered, and outcomes were recorded. RESULTS: Sixty-nine patients (73.4%) underwent PRE at a median interval after the initial unplanned resection of 29 days. Twenty-five patients were thought unsuitable for PRE because of the proximity to vital neurovascular bundles. Tumors deemed not feasible for PRE were more likely to be greater than 5 cm (P =.0094) and high grade (P =.0200). Tumor was found in 33 (47.8%) of the PRE specimens, and 24 of these patients (72.7%) were deemed disease free after achieving negative surgical margins. Residual tumor was more likely to be found after PRE in head and neck primary tumors than in trunk wall or extremity primary tumors (P =.0128). There were no local failures in the 60 PRE patients who achieved clear margins. The estimated 5-year event-free and 5-year overall survival rates in these 60 patients were 98.3% +/- 2.0% and 98.2% +/- 2.1%, respectively. CONCLUSIONS: Pretreatment reexcision should be performed whenever feasible in pediatric patients with NRSTS who had an initial unplanned resection. The proportion of patients with residual tumor in the PRE specimen is high, and negative microscopic margins can be achieved after PRE in most patients with residual tumor. Despite delay in obtaining a complete surgical resection, no local recurrences were seen. The possibility of NRSTS should be considered when resecting a soft tissue mass in children, and diagnostic incisional biopsy followed by wide local excision with negative microscopic margins should be the surgical goal.

Adolescent↗
PubMed2002

Antiproliferative activity of the extract of Gleditsia sinensis fruit on human solid tumour cell lines.

BACKGROUND: The fruit extract of Gleditsia sinensis Lam. (GSE) is a traditional herbal medicine that is saponin-rich. However, its activity on solid tumour cell lines has never been demonstrated. METHODS: The activity of GSE was demonstrated in four cancer cell lines (breast cancer MCF-7, MDA-MB231, hepatoblastoma HepG2 and oesophageal squamous carcinoma cell line SLMT-1) using MTT assay, anchorage-independent clonogenicity assay, DNA laddering and in situ cell death detection. RESULTS: The mean MTT(50) (the mean concentration of GSE to reduce MTT activity by 50%) ranged from 16 to 20 microg/ml of GSE. An anchorage-independent clonogenicity assay showed that all of the four solid tumour cell lines gradually lost their regeneration potential after treatment with GSE, DNA fragmentation and TUNEL analysis demonstrated that the action of GSE is both dose- and time course-dependent. CONCLUSIONS: Our results suggest that GSE has a cytotoxic activity and can induce apoptosis in human solid tumour cell lines.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Transfusion of peripheral blood stem cells from donor homozygous for a shared HLA-haplotype: avoiding fatal transfusion-associated graft-versus-host disease while preserving anti-leukemic effect.

BACKGROUND: Fatal transfusion-associated graft-versus-host disease was observed in immunocompetent patients transfused with blood from donors homozygous for a shared haplotype with the recipient (the P-F1 barrier). We tested whether it was possible to carry out successful transplantation in a patient with relapsed acute myeloid leukemia, using peripheral blood stem cells from his HLA-homozygous brother (HLA A2, B46, DRB1 901) who shared a haplotype with the patient (HLA A2, B46,75, DRB1 901,12). METHODS: A CD34 positively selected cell fraction (5.46x 10(6) CD34 cells/kg) was infused first, followed by subsequent infusion of graded doses of donor T cells (total 7.25x10(7) T cells/kg). Nonmyeloablative chemotherapy with idarubicin and cytarabine was given during the transplantation to reduce the leukemic burden and facilitate engraftment. Polymerase chain reaction with the VNTR primers, D1S80, was used to detect engraftment. RESULTS: Complete remission (>300days) and successful donor engraftment (90%) were achieved. CONCLUSIONS: Peripheral blood stem cells transplantation from a donor with a homozygous shared haplotype is possible with a minimal preparative regimen.

Acute Disease↗
PubMed2001

Successful engraftment in two adult patients with severe aplastic anemia using nonmyeloablative conditioning followed by unrelated HLA-mismatched cord blood transplantation.

Umbilical cord blood as an alternative source of hematopoietic stem cells and nonmyeloablative conditioning are very exciting new developments in transplantation. We report here mixed chimerism in two adult patients with severe aplastic anaemia using nonmyeloablative conditioning and two-antigen mismatched cord blood transplantation resulting in satisfactory clinical response. Our results suggest that such transplant is possible with minimal toxicity.

Adolescent↗
PubMed2001

Provision of phenotype-matched blood units: no need for pre-transfusion antibody screening.

BACKGROUND AND OBJECTIVES: The Hong Kong government is planning to introduce an electronic smart identity card for all seven million citizens in 2003. If the smart card contains the full red cell phenotype/genotype of the individual, it may be possible to transfuse phenotype-matched blood units without pre-transfusion antibody screening. We conducted a feasibility study. DESIGN AND METHODS: Red cell phenotype was determined for 407 donor blood units and 493 patients for whom an antibody screen had been ordered. The computer program selected phenotype-matched blood from the donor stock for the patients according to actual transfusion request. For patients with a positive antibody screen, full crossmatching was carried out with the computer-selected phenotype units. The frequencies of the various red cell phenotypes in the population were calculated from Red Cross data of antigen frequencies. The probabilities of finding at least one unit of phenotype-matched blood from a 300-unit hospital stock and a 4,000-unit Red Cross stock were determined for each phenotype. Cost analysis was performed. RESULTS: Ninety-two out of 493 patients received a total of 395 blood units. The required number of phenotype-matched blood units could be found for 92 patients using a 300-unit pool and for all patients using a 4,000-unit pool. We calculated that phenotype-matched blood could be provided for more than 98% of patients without antibody screening. The total cost of the project is US$ 98 million with potential savings of US$ 14 million per year. INTERPRETATION AND CONCLUSIONS: It is feasible and cost-effective to transfuse patients with phenotype-matched blood without antibody screening using a smart card system.

Blood Group Antigens↗
PubMed2000

Improvement in transfusion safety using a specially designed transfusion wristband.

Fatal haemolytic transfusion reaction due to ABO incompatibility occurs mainly as a result of clerical error. A blood sample drawn from the wrong patient and labelled as another patient's will not be detected by the blood bank unless there is a previous ABO grouping result. We report here the detection of such clerical error by the use of a specially designed transfusion wristband. The wristband has the following special features: (i) once attached, it cannot be removed except by cutting; (ii) it has a pocket containing a transfusion label; (iii) a unique transfusion barcode is printed on each transfusion label and the corresponding wristband simultaneously by computer technology; (iv) a transfusion label removed from the wristband after attachment to the patient has a characteristic tear-mark distinguishing it from one removed prior to attachment. The blood bank only accepted those specimens bearing the tear-marked transfusion labels. All blood units for this patient were labelled with this unique transfusion code together with the patient's details. The nurses counter-checked the transfusion code on the blood units against the transfusion code on the patient's transfusion wristband prior to transfusion. If the blood sample for compatibility testing was drawn from the 'wrong' patient, the intended patient either did not carry a wristband or the transfusion codes did not match at all. Pretransfusion compatibility tests were performed on 2189 patient samples using this procedure. It was well accepted by both ward and blood bank staff. Two potential mismatched transfusions were avoided. These two clerical errors would not have been detected because neither patient had previous ABO grouping results.

Blood Banks↗
PubMed2000

Salmonella typhimurium: a rare cause of colonic ulceration and perforation in infancy.

A rare case of a healthy infant with colonic ulcers caused by Salmonella typhimurium infection that presented with colonic perforation, hypovolemic, and septicemic shock is discussed. It stresses the importance of considering an infective process such as salmonellosis in the differential diagnosis of colonic ulceration in an infant and illustrates the unique histologic finding of colonic inflammatory changes with sparing of the small intestine.

Colonic Diseases↗
PubMed2000

Cytogenetics and the biologic basis of sarcomas.

In this past year, a large number of reports have described cytogenetic and biologic studies of sarcomas. The cytogenetic studies provide further evidence that a growing number of sarcomas seem to be defined by consistent chromosomal abnormalities that can be detected using a variety of molecular genetic tests. However, in addition to these specific abnormalities, many sarcomas have other extremely complex genetic changes. This complexity has made it quite difficult to understand the importance of any single abnormality. Laboratory studies complementing these genetic studies have provided further understanding of sarcoma cellular and molecular biology. Importantly, both types of studies have had significant impact in the clinic in the form of more objective diagnostic tests, potential novel prognostic markers, and even new therapeutic strategies. Together, these papers highlight how genetic studies may offer tremendous insight into sarcoma biology. However, they also highlight some limitations of these approaches as well. Novel experimental approaches may be required to facilitate the continued progress in this field toward the development of better therapeutic strategies.

Cell Differentiation↗
PubMed2000

Laparoscopy in the evaluation of the non-palpable undescended testes.

AIM OF STUDY: To examine the role of laparoscopy in the evaluation of the non-palpable undescended testes in paediatric patients. METHOD: A review of all laparoscopies performed for the evaluation of the non-palpable undescended testes in a children's hospital over a 12-month period was conducted. Special attention was paid to the patients' age, the location of the testes at the time of laparoscopy, the subsequent surgical procedures and the complications. RESULTS: Sixteen boys underwent laparoscopy to localise 20 nonpalpable testes. 12 patients had unilateral disease while 4 had bilateral disease. 15 non-palpable testes were intraabdominal, 3 had inguinal testicular remnants and 2 had 'vanished'. A contralateral inguinal hernia was incidentally found in one patient. A patient with epididymal-gonadal non-union was not apparent at laparoscopy. There were no post-laparoscopic complications in all 16 patients. CONCLUSION: Laparoscopy is safe and accurate in the evaluation of non-palpable testes in children. The accurate localisation of intraabdominal testes facilitates the development of an optimal surgical strategy.

Adolescent↗
PubMed1998

Lack of structural rearrangement in c-kit and stem cell factor genes in Hong Kong Chinese patients with myelodysplastic syndromes or acute myeloid leukaemia.

Stem cell factor is a haemopoietic growth factor that interacts with the c-kit-encoded transmembrane tyrosine kinase receptor during signal transduction in haemopoietic progenitor stem cells. We have screened 127 Chinese patients with myelodysplastic syndromes or acute myeloid leukaemia for structural rearrangements in the stem cell factor and c-kit genes using Southern blot analysis. No structural rearrangements were detected in any of the bone marrow samples that were tested. It seems that structural rearrangements in the stem cell factor and c-kit genes are rare in Hong Kong patients who have a haematological malignancy.

Journal Article↗
PubMed1997

Low frequency of c-kit expression and detection of an aberrant Kit message among Hong Kong Chinese myelogenous leukaemia patients.

The c-kit proto-oncogene encodes a transmembrane tyrosine kinase receptor. It is expressed by the primitive CD34 positive haemopoietic stem cells and interacts with the Kit ligand for signal transduction. It was reported to be expressed in over 80% of acute myelogenous leukaemia (AML) patients in North America and Japan. We analyzed 20 AML patients for c-kit expression using either Northern blot analysis or flow cytometry with the YB5.B8 anti-c-kit antibodies. Only 6 out of 20 AML patients expressed the c-kit mRNA or protein product. However, a previously unreported abnormal sized 1.7-1.9 kb transcript was detected in the blast cells of 1 AML patient, 1 acute mixed lineage leukaemia patient and 1 chronic myelogenous leukaemia (CML) patient in myeloblastic transformation. Our data suggested that in most Hong Kong Chinese AML patients, leukaemia transformation may have occurred at a c-kit negative stage. Alternatively, the abnormal sized c-kit transcript that was detected in some Chinese myeloid leukaemia patients may represent an aberrant c-kit receptor that plays an important role in leukaemogenesis.

Blotting, Southern↗
PubMed1997

Randomized controlled trial of primary fistulotomy with drainage alone for perianal abscesses.

PURPOSE: Primary fistulotomy may be advantageous for perianal abscesses because unlike ischiorectal abscesses, fistulas are more commonly found and can be laid open with full preservation of the external anal sphincters. Therefore, a randomized, controlled trial was conducted to compare primary fistulotomy with incision and drainage alone, specifically for perianal abscesses. METHODS: Fifty-two consecutive patients (43 males; mean age, 40 (standard error of mean, 2) years) with perianal abscesses were randomized to treatment by either incision and drainage (controls; N = 28) or fistulotomy (N = 24). Patients were followed up clinically for a mean of 15.5 (standard error of the mean, 0.7) months. Anorectal manometry was also performed before, six weeks, and three months after surgery. RESULTS: Persistent fistulas developing after surgery were significantly more common after incision and drainage (N = 7; 25 percent) than after fistulotomy (N = 0; P = 0.009). One patient in each group was also found to have a residual abscess, which required repeat drainage. All patients remained fully continent. The anal pressures after incision and drainage and fistulotomy were not significantly different. Operative time, hospital stay, and time for the wound to heal completely were the same in both groups. CONCLUSIONS: Primary fistulotomy at the time of drainage for perianal abscesses results in fewer persistent fistulas and no added risk of fecal incontinence.

Abscess↗
PubMed1997

The results of open acromioplasty in impingement syndrome--a retrospective study.

Many published reports have reported generally good results of open acromioplasty in shoulder impingement syndrome. This paper studied retrospectively the results of open acromioplasty done in the Singapore General Hospital. A total of 23 open acromioplasties performed on 22 patients with shoulder impingement syndrome were studied. The post-operative results of the acromioplasties were evaluated using the University of California, Los Angeles (UCLA) shoulder scoring system. With the UCLA shoulder scoring system, results were excellent or good in 14 (60.8%), fair in 7 (30.5%) and poor in 2 (8.7%). At the same time the male sex was identified to have statistically significant better results as compared to the females. There was a trend towards poorer results in those at or above 50 years of age, duration of symptoms of less than 2 years and those with acromiohumeral distance of less than or equal to 1.0 cm. The presence of rotator cuff tears and the duration of follow-up were found not to have any bearing on the post-operative outcome. This procedure seems to be reasonably effective and safe. Careful patient selection and early post-operative rehabilitation with physiotherapy is of utmost importance.

Acromioclavicular Joint↗