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Biomedical subjects

M de Silva

Publications and source records attributed to M de Silva.

At least 55 records · Page 3Linked to original sources
PubMed1993

Selective inhibition of luteinizing hormone action by ethanol in cultured human granulosa cells.

To extend further our previous observations on the inhibition of luteinizing hormone (LH)-induced increases in steroid secretion by ethanol (EtOH) (Alcohol. Clin. Exp. Res. 14:522-527, 1990), cultured human granulosa cells were pretreated with several EtOH concentrations (0-100 mM), and cells were stimulated with human LH (25 ng/ml) or human follicle stimulating hormone (FSH) (100 ng/ml) and the secretion of 17-beta-estradiol (E2) and progesterone (P) was measured. EtOH significantly increased basal E2 secretion in a dose-related manner (0-20 mM); however, in the same concentration range EtOH did not produce consistent changes in FSH-stimulated E2 secretion. In contrast, EtOH decreased LH-stimulated E2 secretion between 0-20 mM such that at 20 mM EtOH, the positive effect of LH was abolished. EtOH increased P secretion by 40% at 20 mM and at 100 mM, there was a 100% increase. The FSH-stimulated P secretion was not consistently changed by EtOH, whereas LH-stimulated P secretion was decreased in a dose-dependent manner. LH/human chorionic gonadotropin (hCG) receptors in cells exposed to EtOH showed a 15% (p < 0.01) and a 47% decrease at 20 mM and 50 mM EtOH, respectively. At 50 mM EtOH, there was a decrease in LH/hCG receptor number from 2900/cell to 1670/cell, without a change in receptor affinity for hCG and 50 mM EtOH decreased LH/hCG receptors in intact granulosa cells in a time-dependent manner. These results indicate that the selective effects of EtOH on LH action in human granulosa cells may be mediated in part by an action on LH/hCG receptors.

Cells, Cultured↗
PubMed1993

Hemiplegia due to posterior cerebral artery occlusion.

BACKGROUND: Hemiplegia is a rare manifestation of posterior cerebral artery occlusion. The acute clinical picture may be difficult to differentiate from occlusion of the middle cerebral artery. A mechanism for the hemiplegia has not been conclusively determined. CASE DESCRIPTION: We describe a patient with hemiplegia secondary to posterior cerebral artery occlusion by an embolized fragment of a prosthetic valve. Computed tomographic scan showed the foreign body just distal to the origin of the posterior cerebral artery with infarction of its vascular territory. These findings were later confirmed at autopsy. There was no radiological or autopsy evidence of involvement of the other cerebral arteries or their territories. CONCLUSIONS: The patient provides further evidence that occlusion of the posterior cerebral artery just distal to its junction with the posterior communicating artery may produce contralateral hemiplegia without oculomotor nerve nucleus involvement.

Adolescent↗
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↗
PubMed1988

Liver disease and common-bile-duct stenosis in cystic fibrosis.

To determine the incidence of common-bile-duct lesions and their relation to liver disease in cystic fibrosis, we performed hepatobiliary scanning in 50 of 61 patients with cystic fibrosis who had hepatomegaly, abnormal liver function, or both and in 31 of 92 patients with cystic fibrosis who did not have hepatomegaly or abnormal liver function. Ninety-six percent of the patients with liver disease had evidence of biliary tract obstruction, which was defined cholangiographically as a stricture of the distal common bile duct in the majority of cases. All the patients without liver disease had normal intrahepatic and common-duct excretion of tracer. Abdominal pain was significantly more common in patients with common-duct obstruction (P less than 0.001), and enlarged gallbladders occurred only in such patients. Since fasting levels of serum bile acids were elevated in nearly half these patients, irrespective of the severity of their liver disease, serum bile acids may be markers of the severity of the common-duct lesion. We conclude that strictures of the distal common bile duct are common in patients with cystic fibrosis and liver disease. This association requires further study, since surgical relief of common-duct obstruction may prevent or ameliorate the hepatic complications of cystic fibrosis.

Adolescent↗
PubMed1988

HIV surveillance by testing saliva.

Saliva specimens were tested for HIV antibody (anti-HIV) by an immunoglobulin G (IgG) antibody capture radioimmunoassay (GACRIA) and three sensitive commercial assays. In tests on 460 seronegative subjects and 196 seropositive subjects GACRIA was 99.8% specific and 100% sensitive. The Wellcome HIV monoclonal and Abbott recombinant DNA enzyme-linked immunosorbent assays (ELISAs) were also highly specific (99.8%, 100%) but they were less sensitive (90.9%, 82.0%). The Fujirebio particle agglutination assay was sensitive (97.8%) but its specificity was poor (84.1%). In testing saliva specimens from populations with an anti-HIV prevalence greater than 0.5%, sampling by GACRIA alone could provide a good estimate of the true prevalence. For true prevalences less than 0.5% good estimates could only be obtained if positive GACRIA reactions were confirmed by another independent salivary assay. Salivary testing for anti HIV is a convenient and potentially an accurate epidemiological tool.

Acquired Immunodeficiency Syndrome↗
PubMed1987

The effect of naturally occurring Rh antibodies on the survival of serologically incompatible red cells.

Investigations on six males with naturally occurring Rh antibodies are described. In two subjects in whom the antibody (one anti-E and one anti-D) could be detected only by a two-stage papain technique, the survival of incompatible red cells was normal. In the remaining four subjects, the antibodies (two anti-E and two anti-D) could be detected by the indirect antiglobulin test and, in these, incompatible red cells were destroyed at an accelerated rate; in two of the subjects, 75-99% of the cells were cleared within 24 h; in the other two, 50% of the cells were cleared within 24 h and the remaining cells were cleared far more slowly. All six antibodies were mainly or wholly IgG; a clear-cut immune response was observed in only one case.

Coombs Test↗
PubMed1986

Assessment of inflammation in the rheumatoid knee joint: correlation between clinical, radioisotopic, and thermographic methods.

Standard clinical methods of assessing joint inflammation are being supplemented increasingly by radioisotopic and thermographic studies. However, the correlation between these different methods has not been firmly established. In the quantification of synovitis by infrared thermography we have shown that the heat distribution index (HDI) based on thermal pattern is more reliable and is less affected by diurnal variations in joint temperature than the commonly used thermographic index, which is based on average skin temperature values. In 20 patients with rheumatoid arthritis whose knees were being treated with intra-articular steroid we obtained 184 serial paired observations over a period of 24 weeks for clinical assessment, HDI, and 99mTc pertechnetate uptake. We found significant correlations (p less than 0.001) between the three methods of assessment (except for pain and HDI (p = 0.116)).

Adult↗
PubMed1986

Spinal arteriovenous malformation presenting at birth: case report.

A newborn with paraplegia and evidence of a subarachnoid hemorrhage was found to have a spinal arteriovenous malformation. The arteriovenous malformation was managed by direct surgical obliteration. This patient is the youngest ever reported to have this disorder and the youngest so treated.

Angiography↗