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Biomedical subjects

S De Silva

Publications and source records attributed to S De Silva.

14 recordsLinked to original sources
PubMed2001

Contractile proteins in pericytes at the blood-brain and blood-retinal barriers.

Evidence from a variety of sources suggests that pericytes have contractile properties and may therefore function in the regulation of capillary blood flow. However, it has been suggested that contractility is not a ubiquitous function of pericytes, and that pericytes surrounding true capillaries apparently lack the machinery for contraction. The present study used a variety of techniques to investigate the expression of contractile proteins in the pericytes of the CNS. The results of immunocytochemistry on cryosections of brain and retina, retinal whole-mounts and immunoblotting of isolated brain capillaries indicate strong expression of the smooth muscle isoform of actin (alpha-SM actin) in a significant number of mid-capillary pericytes. Immunogold labelling at the ultrastructural level showed that alpha-SM actin expression in capillaries was exclusive to pericytes, and endothelial cells were negative. Compared to alpha-SM actin, non-muscle myosin was present in lower concentrations. By contrast, smooth muscle myosin isoforms, were absent. Pericytes were strongly positive for the intermediate filament protein vimentin, but lacked desmin which was consistently found in vascular smooth muscle cells. These results add support for a contractile role in pericytes of the CNS microvasculature, similar to that of vascular smooth muscle cells.

Actins↗
PubMed2001

Tuberculous ureteric stricture.

The management of a young woman with a ureteric stricture is a challenge to the urologist. Genitourinary tuberculosis can cause ureteric strictures, with minimal symptoms. Untreated, it can lead to impairment of renal function. Diagnosis of genitourinary tuberculosis may be delayed until histopathological assessment. Drug treatment and reconstructive surgery produce good results.

Adult↗
PubMed1999

Pitfalls in cytological diagnosis of autoimmune thyroiditis.

The aims of this study are to document pitfalls in cytologic diagnosis of autoimmune thyroiditis (AT) and highlight possible ways to minimize them. One hundred consecutive thyroid aspirates with features diagnostic or suggestive of AT, performed and reported by the first author, were included in the study. Follow-up was traced and cytologic features responsible for indecisiveness were re-assessed in those reported as suggestive of AT. The features were then correlated with the results of serologic and thyroid function tests and clinical features, and an attempt was made to amend the final diagnosis using an integrated approach. Seventy eight were diagnostic and 22 were suggestive of AT. In the latter 22, features responsible for the indecisiveness were: cytologic atypia, in the form of nuclear enlargement, irregularity and grooves and altered chromatin texture, in 14 (64%); nucleoli with suspicion of a coexisting neoplasm in three (13.6%), two of which showed epithelial preponderance, crowding and discohesion; sparse inflammation in four (18%); a predominant lymphoid population without epithelial cells resembling a reactive lymph node in one (4.5%); co-existing toxic features in two (9%); and scanty smears in one (4.5%). Eighteen of the 22 suspected of AT had follow-up. Six had been assessed histologically; three with features suspicious of a neoplasm were diagnosed respectively as a papillary carcinoma (PC), Hurthle cell carcinoma (HCC) and a multinodular goitre (MNG) with degenerate changes. The other three were confirmed as AT; one with cytologic atypia, one with sparse inflammation and the third as cytologically resembling a reactive lymphnode. In ten of the remaining 12, the final diagnosis could be revised following an integrated approach with possible reduction of the indecisiveness. Potential pitfalls are: cytologic atypia occurring in AT; abundance or scarcity of background inflammation; low cell yield; and co-existing toxicity and malignancies. Epithelial preponderance over inflammation, nuclear crowding, severe atypia and cell discohesion should raise the possibility of a neoplasm in spite of other features of AT. Awareness of possible pitfalls and adopting an integrated approach, especially in difficult situations, will minimize pitfalls.

Adenocarcinoma↗
PubMed1999

Multicentric origin of hemochromatosis gene (HFE) mutations.

Genetic hemochromatosis (GH) is believed to be a disease restricted to those of European ancestry. In northwestern Europe, >80% of GH patients are homozygous for one mutation, the substitution of tyrosine for cysteine at position 282 (C282Y) in the unprocessed protein. In a proportion of GH patients, two mutations are present, C282Y and H63D. The clinical significance of this second mutation is such that it appears to predispose 1%-2% of compound heterozygotes to expression of the disease. The distribution of the two mutations differ, C282Y being limited to those of northwestern European ancestry and H63D being found at allele frequencies>5%, in Europe, in countries bordering the Mediterranean, in the Middle East, and in the Indian subcontinent. The C282Y mutation occurs on a haplotype that extends </=6 Mb, suggesting that this mutation has arisen during the past 2,000 years. The H63D mutation is older and does not occur on such a large extended haplotype, the haplotype in this case extending </=700 kb. Here we report the finding of the H63D and C282Y mutations on new haplotypes. In Sri Lanka we have found H63D on three new haplotypes and have found C282Y on one new haplotype, demonstrating that these mutations have arisen independently on this island. These results suggest that the HFE gene has been the subject of selection pressure. These selection pressures could be due to infectious diseases, environmental conditions, or other genetic disorders such as anemia.

Alleles↗
PubMed1991

Young women's work and family formation in Sri Lanka.

"Patterns of family formation in Sri Lanka resemble those of wealthier nations, with late marriage, delayed childbearing, and moderately low fertility. This article addresses two questions: How have these family formation patterns emerged in the absence of the normally expected levels of economic development? And what activities have occupied young women in the premarital, prechildbearing period? Answers are suggested by data from three sources: the 1981 census; a set of focus-group discussions on the rights, obligations, and aspirations of young women related to marriage, work, childbearing, and child care; and a sample survey of 1,535 women of ages 15-30 in Kalutara District. The article describes the interplay of socioeconomic and familial forces that have affected the status of young Sri Lankan women."

Asia↗
PubMed1990

Fetal macrosomia--maternal risks and fetal outcome.

Two hundred eighty-four macrosomic babies of 4000 g or over at birth were compared with an equal number of appropriate weight term infants, to identify maternal risk factors and fetal outcome. Maternal obesity, grand multiparity, diabetes mellitus and postmaturity were the major maternal risks. Prolonged labor, shoulder dystocia and injury to infant following instrumental delivery for mid-cavity arrest were the major fetal risks. A protocol for management of fetal macrosomia is proposed.

Adult↗
PubMed1989

Obstetric sequelae of female circumcision.

Circumcision of the female has been reported to give rise to major complications both to the mother and the infant during delivery, resulting in increased maternal morbidity and fetal loss. In a controlled series of 167 circumcised patients, receiving optimal ante-natal and intra-partum care in hospital, we observed only short-term complications at delivery, with no long-term effects on the mother or the baby. We conclude that these patients should all be delivered in hospitals with specialised units.

Adolescent↗
PubMed1988

Enzyme immunoassay (EIA) in the rapid diagnosis of gonorrhoea.

The diagnostic value of a new, modified enzyme immunoassay (EIA) (Gonozyme; Abbott Laboratories, North Chicago III) was evaluated for the rapid antigenic detection of Neisseria gonorrhoeae in endocervical and urethral specimens. EIA results were compared with those of Gram stain (GS) and conventional culture tests. EIA sensitivity and specificity for male patients attending dermatovenerological clinic were 100% and 96.8% respectively in comparison to 86.7% and 96.8% obtained by Gram staining. For female Obstetrics-Gynaecology patients EIA sensitivity of 100% was highly significant compared to 50% sensitivity by the Gram stain. In culture, 30 strains of N. gonorrhoeae were isolated from 125 male specimens and 2 from 105 specimens from females; this suggests a prevalence of N. gonorrhoeae of 24% in males and 1.9% in females. In vitro antibiotic sensitivity testing indicated 55% resistance to penicillin and 43% to ampicillin in these isolated strains; all were sensitive to erythromycin/tetracycline. 12% of the strains were beta-lactamase producers.

Evaluation Studies as Topic↗
PubMed1978

Roundworm granuloma of the anterior abdominal wall.

A case of migration of a gravid female roundworm into the peritoneal cavity is reported. The presenting feature, a lump in the anterior abdominal wall, has not previously been documented. Fertilized ova of the worm were found in miliary peritoneal granulomata, and showed development up to the eight-cell stage.

Abdominal Muscles↗
PubMedDate not supplied

Iron overload and iron-chelating therapy in hemoglobin E-beta thalassemia.

Whereas hemoglobin (Hb) E-beta thalassemia is recognized as probably the most common serious hemoglobinopathy worldwide, its natural history remains poorly defined. The interaction of hemoglobin E and beta-thalassemia result in a wide spectrum of clinical disorders, some indistinguishable from thalassemia major and some milder and not transfusion-dependent. Partially as a result of this wide range of phenotypes, clear guidelines for approaches to transfusion and to iron-chelating therapy for patients with Hb E-beta thalassemia have not been developed. By contrast, data that have accumulated during the past 10 years in patients with beta-thalassemia permit a quantitative approach to the management of iron overload and provide guidelines for the control of body iron burden in individual patients treated with iron-chelating therapy. These guidelines may be applicable to patients with Hb E-beta thalassemia. Preliminary evidence from our studies of iron loading in affected patients with Hb E-beta thalassemia in Sri Lanka suggest that this disorder may be associated with variable, but accelerated, gastrointestinal iron absorption, and that the iron loading associated with chronic transfusions in patients with Hb E-beta thalassemia is similar to that observed in patients with beta-thalassemia. These data, in the only cohort of patients with Hb E-beta thalassemia to have undergone quantitative assessment of body iron burden, suggest that the principles that guide assessment of iron loading and initiation of chelating therapy in patients with beta-thalassemia may be generally applicable to those with Hb E-beta thalassemia. Further quantitative studies in both nontransfused and transfused patients will be necessary to permit firm conclusions.

Adult↗