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Biomedical subjects

W F Ng

Publications and source records attributed to W F Ng.

At least 19 recordsLinked to original sources
PubMed2006

Takayasu's arteritis: a cause of prolonged arterial stiffness.

OBJECTIVES: Cardiovascular disease is a major cause of mortality and morbidity in patients with Takayasu's arteritis (TA). Increased arterial stiffness is an independent risk factor and predictor of cardiovascular mortality in a variety of diseases. Pulse wave velocity (PWV) and the augmentation index (AI) are used as clinical measurements of arterial stiffness. METHODS: Data are presented from 10 patients with TA and 11 normal controls obtained between 2000 and 2004. Arterial compliance was assessed non-invasively by measurement of PWV, using the Complior system, and calculation of the aortic AI. RESULTS: TA patients (mean age 40.8+/-13.2 yr) were compared with a control group of healthy women from a parallel study (mean age 32.3+/-5.5 yr). The mean carotid-femoral PWV (PWV-CF) was higher in TA patients (P = 0.03). In addition, both aortic AI derived from the radial artery (P = 0.002) and carotid AI (P = 0.03) were higher in TA patients compared with controls. PWV-CF did not correlate with CRP (r = - 0.23, P = 0.23) or ESR (r = - 0.19, P = 0.27). Similar results were obtained for the correlation of carotid-radial PWV with CRP (r = 0.15, P = 0.32) and ESR (r = 0.33, P = 0.14). CONCLUSIONS: Our data show that TA is associated with elevated arterial stiffness in the central aorta, which may persist when the disease is quiescent. These data suggest that PWV represents a means by which cardiovascular risk can be detected and monitored in TA, and highlights the importance of effective management of cardiovascular risk factors in these patients.

Adult↗
PubMed2006

Three-dimensional ultrasound findings of spondylocostal dysostosis in the second trimester of pregnancy.

Spondylocostal dysostosis (SCD) is a rare congenital disorder that is characterized by vertebral segmentation and formation defects, and asymmetrical rib anomalies. We describe a case diagnosed during the second trimester of pregnancy with the sonographic features of abnormal alignment of the spine, hemivertebrae in the thoracic spine and kyphoscoliosis. Three-dimensional ultrasound demonstrated a 'fan-like' rib cage with fusion of the ribs. The postmortem findings confirmed the ultrasound findings and were consistent with SCD.

Abortion, Therapeutic↗
PubMed2006

The placentas of patients with severe acute respiratory syndrome: a pathophysiological evaluation.

AIMS: The pathology of the placentas delivered from pregnant women who had severe acute respiratory syndrome (SARS) in Hong Kong was studied. METHODS: The pathology of the placentas was retrospectively studied in detail and compared with control sets. The clinical data of the women and neonates were also reviewed. RESULTS: A total of seven placentas were studied. The placentas from two women convalescent from SARS in the first trimester were normal. In three placentas delivered in the acute stage of SARS, there were increases in intervillous or subchorionic fibrin which might be related to disturbances in maternal placental blood flow due to the hypoxic respiratory disease. Extensive fetal thrombotic vasculopathy (FTV) with sharply demarcated zones of avascular fibrotic villi was noted in the placentas of two patients convalescent from SARS in the third trimester. Both pregnancies had intrauterine growth retardation, oligohydramnios and newborns small for gestation. The aetiology of the FTV might be related to thrombotic tendency due to SARS or placental hypoxia. CONCLUSIONS: This report highlights placental pathology that was probably the result of pathophysiological alteration of the maternal fetal unit during SARS. Further studies are required to delineate the relationship between severe maternal respiratory disease, placental pathology and pregnancy outcome.

Adult↗
PubMed2005

Factors influencing cardiac auscultation proficiency in physician trainees.

INTRODUCTION: We assessed the accuracy of physician trainees in identifying different cardiac sounds and examined the factors influencing their cardiac auscultation proficiency. METHODS: A total of 106 physicians in the Family Medicine Training Programme were asked to identify 10 cardiac sounds played sequentially on the Littmann electronic stethoscope, which functioned as a surrogate patient. Their auscultation accuracy was scored numerically out of a maximum of 10. Demographical data of the physicians was collected prospectively. RESULTS: The mean (+/-SD) auscultation proficiency score of the study population was 4.0 +/- 1.7. Physicians who graduated in 1994 or earlier fared significantly poorer than those who obtained their Bachelor of Medicine and Bachelor of Surgery degrees between 1995 and 2000 (p-value equals 0.02). Auscultation proficiency was not related to current practice, previous years of primary care, cardiology, internal medicine or paediatric medicine postings, or cumulative years of postings. Normal heart sounds were most accurately identified. Prosthetic cardiac sounds were better identified than other extra-cardiac sounds while systolic murmurs were more accurately identified than diastolic murmurs. Tachycardia had the lowest identification rate. CONCLUSION: Our data suggest that cardiac auscultation skill declined with time, being significantly impaired eight years after graduation. We suggest that there is a need for retraining in the form of continuing medical education to address not only new knowledge and skills, but also basic skill competency.

Adult↗
PubMed2004

Re-emergence of fatal human influenza A subtype H5N1 disease.

Human disease associated with influenza A subtype H5N1 re-emerged in January, 2003, for the first time since an outbreak in Hong Kong in 1997. Patients with H5N1 disease had unusually high serum concentrations of chemokines (eg, interferon induced protein-10 [IP-10] and monokine induced by interferon gamma [MIG]). Taken together with a previous report that H5N1 influenza viruses induce large amounts of proinflammatory cytokines from macrophage cultures in vitro, our findings suggest that cytokine dysfunction contributes to the pathogenesis of H5N1 disease. Development of vaccines against influenza A (H5N1) virus should be made a priority.

Animals↗
PubMed2003

Histopathological findings of the nose of Down syndrome abortuses.

Recent reports of absent nasal bone in fetuses with Down syndrome have sparked much interest in the use of this finding for the screening of Down syndrome. We describe the histopathological findings of nasal bones of two fetuses with Down syndrome, one with absence and the other with normal ossification of the nasal bone. We propose that histopathological examination of the nasal bone could improve the accuracy of diagnosis of nasal hypoplasia among Down syndrome abortuses.

Abortion, Induced↗
PubMed2003

Chondroblastoma of the lumbar spine with cauda equina syndrome.

STUDY DESIGN: Case report. OBJECTIVE: To describe the clinical presentations, radiological features and clinical progress of a rare case of chondroblastoma of the lumbar spine. SETTING: Regional Hospital, Hong Kong, China. METHOD: A 54-year-old male patient presented with low back pain and left sciatica. X-ray and MRI revealed tumour infiltration of the fifth lumbar vertebrae and left paraspinal muscles, which was found to be a chondroblastoma by repeated open biopsies. The tumour was removed surgically by combined anterior and posterior approaches, followed by spinal fusion and instrumentation. RESULTS: The anterior tricortical bone graft was complicated with fracture and nonunion. Surgical re-exploration confirmed local recurrence of tumour macroscopically and histologically. The patient developed symptoms and signs of cauda equina syndrome gradually despite repeated surgery and irradiation. The patient eventually died of complications of local recurrence and neurological deficit at 3 years and 8 months after the first operation. CONCLUSION: This is the first case report of chondroblastoma of the lumbar spine. The clinical profile of this patient and the evidence from the literature review suggests that spinal chondroblastoma has a very aggressive behaviour with high recurrence and mortality rate.

Bone Neoplasms↗
PubMed2001

Human CD4(+)CD25(+) cells: a naturally occurring population of regulatory T cells.

Despite thymic deletion of cells with specificity for self-antigens, autoreactive T cells are readily detectable in the normal T-cell repertoire. In recent years, a population of CD4(+) T cells that constitutively express the interleukin-2 receptor-alpha chain, CD25, has been shown to play a pivotal role in the maintenance of self-tolerance in rodent models. This study investigated whether such a regulatory population exists in humans. A population of CD4(+)CD25(+) T cells, taken from the peripheral blood of healthy individuals and phenotypically distinct from recently activated CD4(+) T cells, was characterized. These cells were hyporesponsive to conventional T-cell stimuli and capable of suppressing the responses of CD4(+)CD25(-) T cells in vitro. Addition of exogenous interleukin-2 abrogated the hyporesponsiveness and suppressive effects of CD4(+)CD25(+) cells. Suppression required cell-to-cell contact but did not appear to be via the inhibition of antigen-presenting cells. In addition, there were marked changes in the expression of Notch pathway molecules and their downstream signaling products at the transcriptional level, specifically in CD4(+)CD25(+) cells, suggesting that this family of molecules plays a role in the regulatory function of CD4(+)CD25(+) cells. Cells with similar phenotype and function were detected in umbilical venous blood from healthy newborn infants. These results suggest that CD4(+)CD25(+) cells represent a population of regulatory T cells that arise during fetal life. Comparison with rodent CD4(+)CD25(+) cells suggests that this population may play a key role in the prevention of autoimmune diseases in humans.

Adult↗
PubMed2001

Repeated intestinal perforation caused by an incomplete form of Behçet's syndrome.

Behçet's disease, as initially described, is a triad of recurrent oral and genital ulcers and relapsing uveitis. The incomplete form, in which there is no ocular involvement, has been described in Japan and Korea, but this is not commonly recognized in the southern Chinese. We reported herein a rare case of repeated intestinal perforations caused by an incomplete form of Behçet's syndrome in a southern Chinese man.

Aged↗
PubMed2001

Infantile myofibromatosis of the ovary presenting with ascites.

We report the first case of ovarian infantile myofibromatosis (IM) presenting with gross ascites in a 2-month-old girl. There was no evidence of recurrence of ascites or tumour 5 years after complete excision. IM has to be considered in the differential diagnosis of ovarian tumours in infants. Despite having the alarming histologic features of high cellularity, brisk mitotic activity, vascular invasion and necrosis, the tumour responded well to surgery alone without aggressive adjuvant therapy. The case is reported to expand the spectrum of 1) ovarian tumour pathology; 2) infantile myofibromatosis distribution; 3) causes of infantile ascites.

Ascites↗
PubMed2001

Inflammatory pseudotumor-like follicular dendritic cell tumor: a distinctive low-grade malignant intra-abdominal neoplasm with consistent Epstein-Barr virus association.

Follicular dendritic cell (FDC) tumors are uncommon neoplasms that can involve lymph nodes or extranodal sites. They can exhibit a broad spectrum of histologic appearances and behavior, but the intra-abdominal ones usually pursue an aggressive course. The purpose of this study was to characterize a distinctive variant of FDC tumor morphologically mimicking inflammatory pseudotumor through analysis of the clinicopathologic features of 11 cases. The patients included 10 women and one man (age range, 19-61 years; median age, 40 years) who presented with abdominal discomfort or pain. Six patients had systemic symptoms such as marked weight loss, fever, or malaise. All tumors occurred in intra-abdominal sites: liver (n = 7), spleen (n = 3), and peripancreatic region (n = 1). Of the nine patients with follow-up data, six were alive and well, one developed recurrence at 9 years, and two had repeated recurrences over many years. Grossly, the tumors were usually solitary and fleshy, punctuated by areas of hemorrhage and necrosis. Histologically, in a background of abundant lymphocytes and plasma cells were dispersed spindle or ovoid cells with vesicular nuclei and distinct nucleoli. The degree of nuclear atypia was variable, and some nuclei could be grotesque or resemble Reed-Sternberg cells. Focally, spindle cell fascicles could be formed. The atypical cells were immunoreactive for FDC markers such as CD21/CD35, CD23, and CNA.42. In situ hybridization for Epstein-Barr virus (EBV)-encoded RNA was positive in all cases, remarkably highlighting the spindle cells and their atypia. EBV-latent membrane protein-1 was expressed commonly, albeit often focally and weakly. Therefore, inflammatory pseudotumor-like FDC tumor represents a distinctive variant of FDC tumor that differs from conventional FDC tumor in the following aspects: marked female predominance; selective localization in intra-abdominal sites, especially the liver and spleen; frequent presence of systemic symptoms; indolent behavior despite an intra-abdominal location; dispersed distribution of tumor cells and prominent lymphoplasmacytic infiltration; and consistent association with EBV.

Abdominal Neoplasms↗
PubMed2001

A Chinese patient with non-HFE-linked iron overload.

The gene for hemochromatosis (HFE) was recently identified and contains two missense mutations: C282Y and H63D. The C282Y mutation is found homozygous in approximately 85% to 90% of patients of Northern European ancestry with hereditary hemochromatosis. There are no previous reports with results of genetic testing in Chinese patients with regard to iron overload. In this case report, we describe a Chinese woman with marked hepatic iron overload that was nonfamilial, with unusual biopsy findings, in whom neither the C282Y nor the H63D mutations in HFE were found.

Aged↗