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Biomedical subjects

M de Silva

Publications and source records attributed to M de Silva.

15 recordsLinked to original sources
PubMed1991

Development of non-Rh antibodies in volunteers stimulated for the production of hyperimmune anti-D.

At the North London Blood Transfusion Centre, red cells from accredited Rh-D-positive donors, matched for all antigens capable of inducing clinically significant antibodies, are used to stimulate immune plasma donors to achieve higher anti-D levels. Despite such careful matching, antibody to the relatively non-immunogenic M antigen developed in 3 out of 20 NN donors (15%) stimulated with M-positive cells. In general, good responders to the Rh antigen D are good responders to other red cell antigens; our report exemplifies the importance of using fully matched accredited red cells for immune stimulation and the need to perform thorough antibody screening after each stimulation.

Antibody Formation↗
PubMed1991

Infantile hepatic haemangioma: investigation and treatment.

Infantile hepatic haemangiomas are benign tumours which tend to regress in late infancy. We describe five infants with hepatic haemangioma, three of whom developed congestive cardiac failure. Technetium-99m labelled red blood cell scan was useful in the diagnosis and follow-up of the lesion. The three symptomatic infants were treated with prednisone (2 mg/kg per day) for 2 months in addition to digoxin and diuretics. Significant clinical improvement occurred within 3 weeks in each case. We conclude that the red blood cells scan is a good non-invasive diagnostic test and recommend corticosteroids as initial management for symptomatic infantile hepatic haemangiomas.

Diagnostic Imaging↗
PubMed1990

Sequestrated meningoceles of scalp: extracranial meningeal heterotopia.

Sequestrated meningocele of the scalp has seldom been reported and is difficult to diagnose. Clinically it resembles dermoid cyst, hemangioma, or alopecia; radiographs and computed tomographic scans reveal no cranial bone defect, and surgery discloses no communication with the cranial cavity. Histologically, the lesion is characterized by a loose arrangement of connective tissue in dermis and subcutis, associated with flattened cells around collagen fibers (meningothelial cells). Most examples are very vascular, sometimes mimicking angioma, and about one third contain small necrotic foci. The meningothelial nature of the lesion is shown by its architectural similarity to communicating meningocele, and its identical immunoperoxidase reactions with vimentin and epithelial membrane antigen. In the 12 cases reported herein, most lesions were small (1 to 1.5 cm), and all but one were noted at birth but usually not resected until the patient had reached age 1 to 4, and one not until the patient was 31 years of age. Five lesions were not midline. We have been unable on histologic grounds to determine whether meningoceles are communicating or sequestrated. Compared with 20 communicating meningoceles, the sequestrated lesions were usually smaller, found in slightly older patients, and much less likely to be associated with hydrocephalus. The local excision of scalp lesions in children should include a search for a small intracranial connection.

Adult↗
PubMed1989

Nasal cerebral heterotopia: the so-called nasal glioma or sequestered encephalocele and its variants.

Twenty two nasal cerebral heterotopias were compared with 11 nasal encephaloceles. No histological feature was found that would allow a communication with the brain to be confidently identified or excluded. Even laminated cerebral cortex with neurones and ependymal canals, suggestive of encephalocele, were found in heterotopias. Distinction required radiological and surgical evidence. However, CT scan could be misleading, in one infant suggesting a cribriform plate defect when none was found at craniotomy. Three children had multiple extracranial glial lesions, two with both heterotopia and encephalocele in the same patient. In a few older children it was extremely difficult to identify brain tissue because of marked replacement by fibrous tissue (up to 95%), leading to one misdiagnosis as fibroma, and considerable fibrosis occurred also in five of six recurrences and in a longstanding small encephalocele. In two heterotopias, cellularity in places approached that of low-grade neoplastic glioma. One nasopharyngeal heterotopia contained multiple mesenchymal tissues suggestive of teratoma. Two midline nasopharyngeal encephaloceles showed adjacent epithelium, possibly vestiges of Rathke's pouch.

Brain↗
PubMed1985

Purification of a metalloproteinase inhibitor from human rheumatoid synovial fluid.

A metalloproteinase inhibitor present in human rheumatoid synovial fluid was purified by a combination of heparin-Sepharose chromatography, concanavalin A-Sepharose chromatography, ion-exchange chromatography and gel filtration. The Mr of the purified inhibitor was 28000 by SDS/polyacrylamide-gel electrophoresis and 30000 by gel filtration. The inhibitor blocked the activity of the metalloproteinases collagenase, gelatinase and proteoglycanase, but not thermolysin or bacterial collagenase. The serine proteinase trypsin was not inhibited. The inhibitory activity was lost after treatment with trypsin (0.5 micrograms/ml) at 37 degrees C for 30 min, 4-aminophenylmercuric acetate (1 mM) at 37 degrees C for 3 h, after incubation for 30 min at 90 degrees C and by reduction and alkylation. These properties suggest that the inhibitor closely resembles the tissue inhibitor of metalloproteinases ('TIMP') recently purified from connective-tissue culture medium.

Arthritis, Rheumatoid↗
PubMed1985

Failure of passively administered anti-Rh to prevent secondary Rh responses.

Rh-negative women, immunized to Rh by previous pregnancies, with only low concentrations of IgG anti-Rh(D) in their plasma were assigned at random to test and control groups (7 subjects in each group). Both groups were challenged with an intravenous injection of 0.28 ml of Rh-positive red cells; in addition, the test group received 500 micrograms anti-Rh intramuscularly. 2 weeks after the injections, all subjects showed an increase in plasma anti-Rh concentration; levels in test and control groups were similar. It is concluded that in Rh-immunized subjects with low levels of IgG anti-Rh a secondary response to Rh cannot be prevented by giving passively administered anti-Rh with the red cells.

Female↗
PubMed1979

Liposomes in arthritis: a new approach.

Intra-articular liposomal cortisol palmitate in a dose equivalent to 2 mg of cortisol produced a worthwhile therapeutic response in patients with rheumatoid arthritis. This may represent a valuable new approach to treatment.

Arthritis, Rheumatoid↗
PubMed1978

The radiology of neonatal necrotizing enterocolitis (NEC). A review of 47 cases and the literature.

The radiological findings in 47 neonates with necrotizing enterocolitis (NEC) are reviewed. The presence of nonspecific, generalized bowel dilatation is stressed as being an important sign in early diagnosis and the progress of the distribution of the dilated loops is important in evaluating progress of the disease process. It is thus the key to the radiology of NEC. Intramural gas and portal venous gas are not always related to the severity of the disease and their disappearance is not always related to clinical improvement. These signs are therefore poor prognostic indicators. Important radiological indications for surgery besides free intraperitoneal gas and free fluid include: 1. diminished bowel gas with asymmetric loops, and 2. persistent dilated loops. Because of the number of colonic strictures seen at our hospital we advise routine barium enemas (several weeks after the acute phase) in all infants who have had NEC. Following bowel resection contrast studies of both distal and proximal remaining bowel are essential to exclude further stricture formation prior to final reanastomosis.

Enterocolitis, Pseudomembranous↗
PubMedDate not supplied

[Chronic infection due to hepatitis B virus in patients less than 16 years of age: therapeutic approach by means of interferon alfa-2b].

Twenty children with chronic Hepatitis B virus infection where treated with alfa interferon 2b and compared with a group of 24 non treated patients with similar age and sex distribution. Both treated and untreated patients, all Hepatitis B surface antigen positive for a minimum of 6 months, were divided in 2 groups according to HBeAg status: positive and negative. The treatment was ambulatory at a dose of 5.000.000 U per square meter of body surface, administered 3 times a week during 16 weeks. Tolerance of the drug was good with secondary reactions only at the beginning of the treatment. The only change in laboratory tests was the normalization of aminotransferases in HBeAg positive children. There was no significant difference between the treated and untreated group of HBeAg positive patients regarding the rate of HBeAg seroconversion. There was a striking difference in negativization of HBsAg in HBeAg negative patients: 8% in the treated group and 81% in the untreated group, this is explained by important epidemiological differences between both groups.

Adolescent↗