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Biomedical subjects

L M Looi

Publications and source records attributed to L M Looi.

At least 91 records · Page 5Linked to original sources
PubMed1990

The histopathological pattern of primary IgA nephropathy in a Malaysian patient population.

In the 10-year period from October 1977 to July 1987, 149 cases of primary IgA nephropathy were histologically confirmed through renal biopsies in the Department of Pathology, University Hospital, Kuala Lumpur. The ages of these patients ranged from 5 to 72 years, with the majority in the 20-30 year age group. There was no sex preponderance. The ethnic distribution showed a significant predominance of Chinese with 107 (71.8%) Chinese, 24 (16.1%) Malays, 15 (10.1%) Indians and 3 others. A wide range of renal glomerular pathology was seen, the commonest being diffuse mesangioproliferative glomerulonephritis (59.1%). Focal proliferative glomerulonephritis (14.1%) followed by minimal change glomerulonephritis (10.7%) were next in order of frequency. Immunofluorescence studies consistently demonstrated heavy and predominant IgA deposition in the mesangium. Weak deposition of C3, IgG and IgM were also observed in various combinations.

Adolescent↗
PubMed1989

Histomorphological variations in systemic AA amyloidosis: clues of AA protein polymorphism.

The histological location of amyloid within various organs in 25 cases of systemic AA amyloidosis was studied with a view to determine whether different morphological patterns exist in this category of amyloidosis. Although morphological variations due to progressive severity of disease were observed, there were appreciable variations in the patterns of amyloid deposition in the kidney and spleen that could not be simply explained on those grounds. Eleven (61%) of 18 kidneys examined showed severe glomerular involvement with mild degrees of vascular deposition while the remaining seven showed predominantly vascular involvement. The glomerular pattern appeared to be more ominous, being significantly associated with severe proteinuria or chronic renal failure. In nine (69%) of 13 spleens examined, amyloid was confined to the walls of small and medium-sized arteries while in the remaining four, vascular involvement was less severe and amyloid was deposited mainly along the reticulin of the white pulp. Possible explanations for these different patterns included resorption and redistribution of amyloid within the body during the course of the disease, and variation in tissue deposition as a manifestation of polymorphism of amyloid proteins. The latter appeared more feasible in view of the recent demonstration of SAA polymorphism and AA heterogeneity in man.

Adolescent↗
PubMed1988

Morphologic differences in the pattern of liver infiltration between systemic AL and AA amyloidosis.

Biopsy and necropsy tissue from 31 unselected patients with systemic amyloidosis, in which there was histologic evidence of liver involvement, were reviewed with reference to the location and pattern of amyloid deposition in the liver. Amyloidosis was classified into AA and AL types on the basis of immunohistochemistry and permanganate reaction of the amyloid deposits. Nineteen were categorized as AA (secondary) and 12 as AL (primary) amyloidosis. Deposition of AA amyloid was limited to the walls of vessels in the portal tract, constituting a "vascular" pattern. In AL amyloidosis, the deposits exhibited a "sinusoidal" pattern in that they were seen along hepatic sinusoids as well as in vessel walls. This difference was statistically significant (P less than .001). The histologic pattern of liver infiltration offers a valuable clue in the classification of systemic amyloidosis and provides information that may be useful in the selection of patients for therapy.

Amyloid↗
PubMed1988

The prognostic significance of grading in borderline mucinous tumors of the ovary.

Fifty-three stage I borderline mucinous tumors of the ovary were placed into four histologic grades according to a simple system of grading based on degree of cell layering, nuclear characteristics, and mitotic count. Three patients died of recurrence and spread of their tumors. All three patients had grade 4 tumors, suggesting that there may be some prognostic value in grading borderline mucinous ovarian tumors.

Adenocarcinoma, Mucinous↗
PubMed1988

An immunohistochemical and morphological study of amyloidosis complicating leprosy in Malaysian patients.

Congo red screening of tissue blocks from 37 consecutive autopsies on leprosy patients revealed 7 cases of systemic amyloidosis, indicating a prevalence rate of 19%. 5 were males and 2 females. All were ethnic Chinese. Their ages ranged from 52 to 85 years with a mean of 69 years. Six had lepromatous leprosy while the remaining 1 had tuberculoid leprosy. In all 7 cases, the amyloid was AA in type, being permanganate-sensitive and immunoreactive with anti-human AA protein antiserum. Hepatic deposition was limited to blood vessels, a pattern typical of AA (secondary) amyloidosis. With regard to renal involvement, 4 showed a predominantly vascular pattern of infiltration while 3 exhibited the more ominous glomerular pattern. Three died of chronic renal failure and 2 of congestive cardiac failure attributable to renal and cardiac amyloidosis respectively. One patient succumbed to septicaemia and the remaining 1 to acute myocardial infarction. AA amyloidosis remains a serious and significant complication of leprosy among Malaysians.

Aged↗
PubMed1987

Tumor-associated tissue eosinophilia in nasopharyngeal carcinoma. A pathologic study of 422 primary and 138 metastatic tumors.

A study of biopsy specimens from 422 consecutive primary nasopharyngeal carcinomas (NPCs) revealed tumor-associated tissue eosinophilia (TATE) in a large proportion (26%) of the tumors. TATE occurred more frequently in nonkeratinizing carcinomas (NKC, 38%) than in the squamous (21%) or undifferentiated (23%) types. There was no sex predilection and no association with the presence of intratumor amyloid deposits. Stromal eosinophilia was also observed in 53 (38%) of 138 metastatic NPCs in lymph nodes, where it had occasionally led to confusion with Hodgkin's disease. TATE may be a feature of diagnostic importance in NPC, although its prognostic significance remains to be ascertained.

Amyloidosis↗
PubMed1987

Autopsy findings in 35 cases of leprosy in Malaysia.

The findings of autopsies performed on 35 leprosy subjects in the University Hospital, Kuala Lumpur, between January 1981 and December 1985 are presented. This is the first report based on autopsy findings from Malaysia. The patients were elderly subjects with a mean age of 74 years. Sixty-six percent had lepromatous leprosy. None had active skin lesions. The most common cause of death was pyogenic infection, particularly bronchopneumonia. Tuberculosis was noted in 25% of the cases. The other important causes of death included cardiac and renal failure. Renal lesions were evident in 71% of the cases, and the most common pathology was interstitial nephritis. Generalized amyloidosis complicated six (17%) patients.

Aged↗
PubMed1986

An investigation of the protein components of amyloid using immunoperoxidase and permanganate methods on tissue sections.

Amyloid deposits in tissue from 8 patients with generalized primary amyloidosis, 11 patients with generalized secondary amyloidosis, 11 nasopharyngeal carcinomas, 11 basal cell carcinomas, 4 islet cell tumours, 4 medullary carcinomas of the thyroid and 9 cases of lichen amyloidosis were studied using the indirect immunoperoxidase and peroxidase-antiperoxidase methods with specific antisera against Amyloid A (AA) protein and human immunoglobulin lambda and kappa light chains. The permanganate method of Wright was also applied to tissue sections. Positive staining for AA protein was observed only in secondary amyloidosis. There was excellent correlation between AA positivity and permanganate sensitivity. Positivity for immunoglobulin light chains was not observed in secondary amyloidosis but was noted in 5 (63%) cases of primary amyloidosis and 18-27% of intratumour amyloidosis. Lichen amyloidosis did not stain for AA protein or light chains. It is shown that assessment of the permanganate reaction and AA positivity of amyloid deposits can reliably differentiate secondary from primary amyloidosis and may contribute significantly to selection of patients for appropriate therapy.

Amyloid↗
PubMed1986

Intratumour amyloidosis in Malaysians: an immunohistochemical study.

Congo red screening of tumour material examined at the Department of Pathology, University of Malaya revealed intratumour deposits of amyloid in 12% of nasopharyngeal carcinomas, 66% of basal cell carcinomas, 100% of medullary carcinomas of the thyroid, 56% of islet cell tumours of the pancreas, 1 out of 16 carcinoids and 1 out of 100 thyroid adenomas. All the deposits were permanganate resistant and did not contain AA protein, indicating that what was encountered was not secondary amyloid. The deposits showed variable staining for immunoglobulin light chains and amyloid P component with a standard peroxidase antiperoxidase method. The possibility that intratumour amyloid has a neoplastic origin is discussed.

Adenoma, Islet Cell↗
PubMed1985

Race-related morphologic variations in hepatocellular carcinoma.

In West Malaysia, hepatocellular carcinoma (HCC) is common in the Chinese and in the members of the Senoi aboriginal tribe, two racial groups with diametrically opposite life-styles. Certain fundamental differences exist between the liver tumors in the two races. In the Senoi, the tumor occurs in a younger age group and there is a greater male preponderance than in the Chinese. There is also a very close relationship between hepatitis B virus infection, chronic active hepatitis, cirrhosis, liver cell dysplasia, and HCC in the Senoi and the tumors generally present as multiple nodules studding both lobes of the liver. In the Chinese, although a relationship between hepatitis B virus infection, HCC, and cirrhosis exists, this association is not as strong as in the Senoi and the tumors are generally large and solitary. The data suggest that, although the hepatitis B virus is probably an important oncogenic agent in both racial groups, there may be a difference in the pathogenesis of HCC in the two races.

Adult↗
PubMed1985

Copper-binding protein in liver cells.

The patterns and incidences of orcein-positive granules of copper-binding protein (CBP) in 2,531 liver biopsy specimens from children and adults with a large variety of liver diseases are reported. Fetal and neonatal livers have high physiologic levels of copper and CBP, which fall to within the adult range by the third to the sixth month of life. Therefore, in liver specimens from children less than 6 months of age, it was not possible to determine whether the orcein-positive granules present represented physiologic or pathologic deposits of CBP. In adults and in children older than 6 months of age, CBP granules were found almost exclusively in association with four main groups of liver diseases: Wilson's disease, chronic biliary disorders, cirrhosis/extensive fibrosis, and primary liver tumors. Orcein-positive granules were never found in patients with acute liver disease. The granules were extremely helpful in distinguishing chronic biliary diseases from acute cholestatic and hepatic disorders, primary biliary cirrhosis from chronic active hepatitis, and primary liver tumors from metastatic tumor deposits.

Acute Disease↗
PubMed1985

Mesangial IGM in minimal change glomerular disease: a clinicopathological study in a Malaysian population.

During a 6 yr period, 105 (69%) of 153 patients in whom a histological diagnosis of minimal change glomerular disease was made had renal biopsy tissue suitable for immunofluorescence examination. Thirty seven (35%) patients showed glomerular mesangial deposits of IgM. All the patients presented with the nephrotic syndrome. We found no significant difference in age and sex prevalence, presentation, response to therapy and glomerular morphology between IgM positive and IgM negative groups. This study suggests that there is no necessity to categorize IgM positive minimal change glomerular disease as a separate entity.

Adolescent↗
PubMed1984

Localized amyloidosis in nasopharyngeal carcinoma.

A study of biopsies from 434 consecutive primary nasopharyngeal carcinomas revealed amyloid deposits in 54 (12%) of the tumours. Amyloid was present in all three histological types of nasopharyngeal carcinoma, but was more frequently observed in nonkeratinizing carcinomas. The amyloid deposits were patchy in distribution and occurred both within tumour cells and extracellularly. A neoplastic origin for this form of amyloid is suggested.

Adolescent↗
PubMed1984

Systemic lupus erythematosus with membranous lupus nephropathy in Malaysian patients.

Thirty-one patients with systemic lupus erythematosus had membranous lupus nephropathy (MLN). They were divided into two groups. Group I consisted of 13 patients who had pure MLN but the patients in Group 2 had segmental proliferation in up to 35 per cent of their glomeruli. The rest of the glomeruli had purely membranous change. The patients of Group 2 were no different from the other MLN patients in terms of age, sex and race. The extrarenal disease in both groups was extensive and severe. The renal disease was usually associated with the nephrotic syndrome or oedema but was asymptomatic throughout in one patient. Both renal and extrarenal features responded to treatment initially but relapses were frequent and often severe. Relapses often occurred as treatment was discontinued or medication reduced. Survival at six years in Group I was 62 per cent and in Group 2 was 50 per cent. Only one patient died with renal failure although five patients had impaired renal function at death. The chief causes of death were disease of the central nervous system and infection.

Adolescent↗