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Biomedical subjects

W L Ng

Publications and source records attributed to W L Ng.

67 records · Page 4Linked to original sources
PubMed1982

Preparation of Epon-embedded renal tissue for scanning electron microscopy.

A method for the preparation of Epon-embedded renal tissue for scanning electron microscopy (SEM) is described. This involves careful removal of Epon by potassium hydroxide in absolute methanol to expose the embedded kidney tissue. The method is simple and gives good surface morphology of the sectioned and trimmed surfaces of the tissue block. Both sectioned and intact glomeruli are well shown. The method also allows SEM observation of tubules and blood vessels.

Epoxy Resins↗
PubMed1981

The ultrastructural morphology of the mesangial cell in IgA nephropathy.

By means of electron microscopy, three types of mesangial cell change were identified in IgA nephropathy. They represented proliferative, phagocytic and resting mesangial cells. The proliferative mesangial cells were characterised by the presence of centrioles, numerous free ribosomes, well developed Golgi apparatus and SER. They were found in the proliferative forms of IgA nephropathy. Phagocytic mesangial cells had numerous spinous cytoplasmic processes, better differentiated RER and numerous dense bodies and lipid inclusions. They were found in all histological forms of IgA nephropathy. The resting mesangial cells were unusual and were occasionally present in cases with normal numbers of mesangial cells.

Centrioles↗
PubMed1981

Absence of the ether lipid tumour marker in diethylnitrosamine-induced rat liver cell cancer.

Tissue levels of neutral O-alkylglycerolipids were measured in rat liver during the course of hepatocarcinogenesis produced by feeding diethylnitrosamine. Enzyme altered foci, not recognizable with conventional histological techniques, were shown to be present in specimens obtained after 3 or 6 weeks feeding the carcinogen. Frank hyperplastic nodules were present at 11 weeks and hepatocellular carcinoma were found in all rats at 18 weeks. At no point during the course of carcinogenesis did the liver show an increase in either-linked neutral glycerolipids, characteristic of animal tumours. On the contrary, lower levels of neutral O-alkylglycerolipids were found in tissues containing hyperplastic nodules or tumour.

Animals↗
PubMed1981

Glomerulonephritis in leprosy.

A renal biopsy from a patient with lepromatous leprosy but no history of erythrema nodosum leprosum (ENL) showed histologic, immunofluorescent, and ultrastructural features typical of immune-complex glomerulonephritis. A literature review found reports of 187 renal biopsies from leprosy patients, with glomerulonephritis in 31% of the cases, and a variety of other renal lesions. This accumulated evidence demonstrates that, contrary to widely held opinion, there is no association between glomerulonephritis and a history of ENL. Furthermore, it suggests that glomerulonephritis in leprosy patients has a similar incidence in lepromatous and non-lepromatous cases. These observations have an important bearing on concepts regarding the pathogenesis of immune complex glomerulonephritis in leprosy and the humoral immune mechanisms in patients with leprosy.

Antigen-Antibody Complex↗
PubMed1981

The pathology of primary IgA glomerulonephritis--a renal biopsy study.

Renal biopsies of 44 Chinese patients with primary IgA glomerulonephritis (IgA Gn) were examined by light (LM), electron (EM) and immunofluorescent microscopy (IF). The diagnosis of IgA Gn was based on IF staining showing predominant mesangial IgA deposition in the absence of systemic diseases. With LM, IgA Gn was not essentially different from other idiopathic forms of glomerulonephritis. The glomerular lesions showed features of focal proliferative glomerulonephritis (45.4%), focal sclerosing glomerulonephritis (25%), minimal glomerular lesions (18.2%) and diffuse mesangial proliferative glomerulonephritis (11.4%). Membranous and membrano-proliferative forms were not encountered. The variable LM findings contrasted markedly with the constancy of IF staining. EM revealed lumpy electron dense deposits in the mesangium in all cases which, in the relative absence of subendothelial and subepithelial deposits, might also be helpful in diagnosis.

Adult↗
PubMed1980

Oligomeganephronic renal hypoplasia.

A case of oligomeganephronic renal hypoplasia is described. The patient presented in infancy with vomiting and diarrhoea and eventually developed progressive renal failure. Glomerular morphometry allowed definitive diagnosis and demonstrated a decrease in number and an increase in size of the glomeruli. Electron dense deposits seen on electron microscopy correlated with positive fluorescence for IgG and simulated overload glomerulitis.

Child, Preschool↗
PubMed1976

Mucin histochemistry of human cholangiocarcinoma.

Histochemical studies of mucins were carried out on 17 autopsy specimens of cholangiocarcinomas associated with clonorchiasis. All tumours produced epithelial mucins which were mixtures of neutral and acid mucopolysaccharides without any histochemically demonstrable components of sialic and uronic acids. The mucins were qualitatively similar to that secreted by normal and Clonorchis-infested bile ducts. However carboxymucins were reduced and sulphomucins were absent or present only in trace amounts in the neoplastic epithelium; in the hyperplastic epithelium in clonorchiasis sulphomucins were abundant. The HID-AB technique for sulphomucins is valuable in differentiating hyperplastic bile ducts and cholangiocarcinoma.

Adenocarcinoma↗
PubMed1976

Coronary arterial fistula.

We report two cases of coronary arterial fistula communicating with the right ventricle. It was noted that the coronary arteries did not spring from the aorta in the normal way. Proximal connections between the coronary arteries and the aorta absent. The lesions were associated with pulmonary valvular atresia, tricuspid valvular stenosis, and intact ventricular septum. We describe the clinical and autopsy findings and discuss the possible pathogenesis.

Coronary Vessel Anomalies↗
PubMed1975

Drill biopsy of the thyroid gland.

Needle drill biopsies were performed on 360 patients presenting with thyroid swellings. The indications and technique are discussed. Surgical treatment was carried out for 154 of the 225 solitary nodules and 82 of the 129 nodular goitres. The overall success rate in obtaining thyroid tissue was 74%. The accuracy rate was 100% in lymphocytic thyroiditis, anaplastic carcinoma and medullary carcinoma. With adenoma, 66% of those presenting as solitary nodules and 44-4% as nodular goitres were correctly diagnosed. Two-thirds of papillary carcinomas were correctly diagnosed by drill biopsy. Only 28-6% of follicular carcinomas were diagnosed before operation. The drill biopsy proved to be a simple procedure, with few complications, and served the purpose of selecting patients for operative treatment.

Adenocarcinoma↗
PubMedDate not supplied

Volcanoes and carcinoma of the thyroid: a possible association.

Environmental factors contributing to incidences of thyroid carcinoma are re-evaluated and emphasized in this study. Thyroid cancers appear to occur independent of endemic goiter, based on epidemiologic and histologic evidence. While environmental factors appear to be important, the specific etiologic agent has not yet been identified or suggested. The number of thyroid cancer incidences available from cancer registries are analyzed in an attempt to identify a specific environmental carcinogenic agent. The presence of active volcanoes that produce abundant lava is found to be the common denominator of Iceland and Hawaii, where the incidence of thyroid cancer is outstandingly high. Comparison with other areas with active volcanoes is made. The presence of a carcinogenic agent in the lava is postulated and its possible mode of action on humans through fish products is hypothesized.

Carcinoma, Papillary↗
PubMedDate not supplied

Safety of disease modifying anti-rheumatic agents in rheumatoid arthritis patients with chronic viral hepatitis.

OBJECTIVE: To examine the safety of the use of disease modifying anti-rheumatic drugs (DMARDs) in rheumatoid arthritis (RA) patients with chronic viral hepatitis (CVH). METHODS: Records of 600 Chinese patients satisfying the ARA criteria for RA in two rheumatology centers were reviewed. Patients with CVH were studied. Liver enzymes were checked before (baseline) and during DMARD use at 3-month intervals or more frequently if necessary. Drug-episodes (D-Ep), defined as the continuous use of DMARD, singly or in combination, for more than 6 months in a patient, were analysed. Changes in serum liver alanine transaminase (ALT) levels as multiples of the upper range of normal were taken to reflect the severity of hepatotoxicity. Changes of ALT to > or = 1.5 times the upper range of normal if they were measured at baseline or > or = 2 times the upper range of normal if they were measured during and after the use of DMARD were considered as abnormal. Control patients included those with CVH alone (n = 623) or RA without CVH (n = 62) matched for age, sex and D-Ep. RESULTS: 30 RA patients were found to have concomitant CVH. One patient was excluded because of use of NSAID alone (n = 1). Among the 29 patients, 23 were HBsAg +ve and 6 were anti-HCV Ab +ve. A total of 47 D-Ep were analysed. 20/47 (42.6%) of D-Ep in 16/29 (55.2%) RA + CVH patients developed abnormal ALT levels after a mean 1.9-year duration of DMARD use. This was statistically significant when compared with 13/94 (13.8%) of D-Ep which ended with abnormal ALT levels in 13/62 (21%) patients with RA alone (p < 0.0001 for D-Ep which ended up with abnormal ALT, and p < 0.02 for the number of patients who developed abnormal ALT) and 128/623 (20.5%) patients with CVH alone (p < 0.005). 53% (9/17) of hydroxychloroquine (HCQ) D-Ep were associated with an abnormal outcome. Corresponding figures for sulphasalazine (SAZP) and oral or intramuscular gold preparations were 55.6% (5/9) and 0% (0/3) respectively. Two patients on methotrexate, used either singly or in combination, had normal ALT levels throughout the study period. One patient on azathioprine developed reactivation of hepatitis B infection. When D-Ep of the RA + CVH group were further analysed, 16/43 (37.2%) and 4/4 (100%) D-Ep which started with normal and abnormal baseline ALT respectively developed further liver enzyme derangement. CONCLUSION: The use of DMARD in RA + CVH patients is associated with a high incidence of hepatotoxicity. The effect is likely to be synergistic. This includes drugs such as HCQ, which is generally believed to be less hepatotoxic.

Adult↗
PubMedDate not supplied

[Clonidine and treatment of arterial hypertension in the pregnant female].

From the results of a non-controlled trial about the successful use of clonidine in 14 hypertensive pregnant women on and on the basis of a bibliographical analysis, the investigators studied the efficacy and safety of this central acting antihypertensive drug. This risk-improvement study reveals that clonidine can be safely and advantageously prescribed for the treatment of hypertension during pregnancy.

Adult↗