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Biomedical subjects

S O'Shea

Publications and source records attributed to S O'Shea.

12 recordsLinked to original sources

A lymphocyte transformation assay for the diagnosis of congenital rubella.

A rubella-specific lymphocyte transformation assay, using cryopreserved mononuclear cells, has been developed and used to evaluate specific responses among 21 children with congenitally acquired rubella (CAR), 25 healthy control children and 10 children with sensorineural deafness of unknown aetiology. Although all 21 children with CAR were seropositive, 12 (57.1%) failed to respond to rubella antigen in the transformation assay. Negative in vitro lymphocyte transformation responses were detected significantly more frequently among congenitally infected children below 3 years of age. Thirteen of the 25 (52%) control children were seropositive; only one of these seropositive children (7.6%) gave a negative transformation response. A negative rubella-specific lymphocyte transformation response in a seropositive child, particularly when aged 3 years or younger, is therefore suggestive of CAR. Four of the 10 children with deafness of unknown aetiology were rubella seropositive but gave negative responses in the transformation assay, suggesting that these children had CAR. Our assay may provide a very useful test for retrospective diagnosis of CAR, particularly in children under the age of 3.

Adult

Persistence of specific IgM and low avidity specific IgG1 following primary rubella.

Persistence of specific IgM in sera following primary rubella infection was compared with the maturation of the specific IgG1 response. 206 sera, from 171 patients with primary rubella, taken 1 day to 2.5 years after onset of illness, were tested. Rubella-specific IgM was detected by M-antibody capture radioimmunoassay in 100% of sera taken 15-28 days after onset, but in only 9% taken 3-4 months after onset. However, using the diethylamine (DEA) shift value (DSV) method, low avidity specific IgG1 was detected in 91% sera taken at 3-4 months and at 5-7 months 21% of sera remained positive. Using an avidity index method, with urea in the wash buffer, none of the sera were positive for low avidity specific IgG1 beyond 3 months after onset. With DEA in the wash buffer, the number of sera positive rose to 38% at 3-4 months. Thus, the DSV method for detecting low avidity specific IgG1 is a useful additional test for confirming or refuting a diagnosis of primary rubella and is of particular value for assessing pregnant patients.

Antibodies, Viral

Rubella virus strains show no major antigenic differences.

To determine whether antigenic differences occur among rubella virus strains, five wild-type strains of rubella virus isolated in the UK, the USA, and in Japan between 1964 and 1987 and four attenuated vaccine strains were compared employing a panel of 28 monoclonal antibodies in neutralization, haemagglutination-inhibition, enzyme immunoassay, and indirect immunofluorescence assays. No antigenic differences were detected which confirms that rubella vaccines will protect against circulating strains and that rubella antigens used in serological tests for screening and diagnosis will detect antibodies induced by all strains.

Antibodies, Monoclonal

Induction of thrombospondin 1 by retinoic acid is important during differentiation of neuroblastoma cells.

Neuroblastoma, a malignant neoplasm that arises in the adrenal medulla or sympathetic ganglion, is one of the most common solid tumors of childhood. Reports that neuroblastomas spontaneously mature to form benign ganglioneuromas have prompted investigations into the efficacy of using agents that induce neuronal differentiation in the treatment of this malignancy. Retinoic acid is one agent in particular that has been shown to induce growth inhibition and terminal differentiation of neuroblastoma cell lines in vitro. Using the human neuroblastoma cell line SMH-KCNR, we have investigated the role of the extracellular matrix protein thrombospondin in retinoic acid induced neuroblastoma differentiation. Treatment with retinoic acid results in a rapid induction (within 4 h) of thrombospondin (TSP) message which is independent of intervening protein synthesis and superinducible in the presence of cycloheximide. This suggests that TSP functions as a retinoic acid inducible immediate early response gene. A concomitant increase in both cell associated and soluble forms of TSP protein can be detected within 24 h of retinoic acid treatment. A functional role for TSP in SMH-KCNR differentiation was established in experiments which showed that exposure to anti-TSP monoclonal antibodies delay retinoic acid differentiation for 48 h. At the time the cells overcome the effects of TSP inhibition, laminin production becomes maximal. Treatment of the cells with a combination of anti-TSP and antilaminin antibodies results in complete inhibition of differentiation.

Cell Differentiation

Quantitation of HIV: correlation with clinical, virological, and immunological status.

A quantitative assay has been used to measure titres of infectious HIV in peripheral blood of symptomatic and asymptomatic patients. Viral titres were assessed in conjunction with virological and immunological status of patients including measurement of p24 antigen, antibody responses to structural (gp41, p24) and regulatory gene products (NEF, REV, TAT, and VIF), determination of beta 2 microglobulin levels and enumeration of lymphocyte subsets. Titres of HIV were significantly higher among symptomatic than asymptomatic patients. Viral load was closely associated with the number of CD4+ cells, the proportion of these cells harbouring HIV increasing with disease progression. Higher titres of infectious HIV among symptomatic patients was also associated with p24 antigenaemia and decreased antibody responses to NEF.

AIDS-Related Complex

HIV excretion patterns and specific antibody responses in body fluids.

HIV excretion patterns and specific antibody responses were evaluated in blood, semen, female genital secretions, saliva, and crevicular fluid. Samples were examined for infectious virus, viral antigens, viral nucleic acid, HIV specific IgG, IgA, anti-nef, and anti-p24. Viral load in peripheral blood appeared to increase with disease progression. The proportion of patients with antibody responses specific for nef and p24 was also lower among patients with more advanced disease. Infectious virus and viral antigens were detected infrequently and at lower levels in body fluids than in blood, which may reflect the presence of local antibodies. HIV nucleic acid was detected in some semen and saliva samples in the absence of infectious virus.

Female

Rubella vaccines.

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Antibodies, Viral

Protracted behavioral effects of neonatal morphine-pellet implantation in male rats.

Male rat pups (Charles Rivers CD albino strain) were implanted subcutaneously with a morphine (M), placebo (P), or no pellet (NP) on Day 5 or 11 of postnatal life. Body weights of both Day 5 and 11 drug-treated males were depressed below those of controls through Day 63 (p < 0.01). On Day 72, compared to P and NP controls, M-treated males showed impaired learning in a Lashley III maze. Day 5, but not Day 11 drug-treated animals showed greater activity-wheel behavior (p < 0.01) than controls on Days 85--86, and less suppression (p < 0.025) of a conditioned emotional response on Day 145. On Day 150, Day 5 M-treated animals showed a reduced steroid response (p < 0.05) to a challenge dose of M (18 mg/kg), suggesting protracted tolerance to the pituitary-adrenal activating effects of M. Members of each treatment group were successfully bred with females on Day 90; no group differences were found in litter size, sex ratios, or birth weights of the offspring. The results of this study indicate that early exposure to M causes long-term impairment of several behaviors in male rats.

Animals

Rubella serology by solid-phase radioimmunoassay: its potential for screening programmes.

Sera from 269 adult females who had experienced naturally acquired or vaccine-induced infection by rubella virus, including immune persons challenged intranasally with rubella vaccine (RA27/3) as well as sera from 100 patients attending antenatal clinics, were tested for rubella antibodies by the conventional haemagglutination inhibition tests (HAI), as well as a newly developed solid-phase radioimmunoassay (RIA) for rubella immunoglobulin G (IgG) antibodies. Following both naturally acquired and vaccine-induced infection, titres by RIA were approximately ten-fold higher than by HAI. The RIA test was particularly useful in assessing the true immune status of those with apparently low levels of HAI antibody and has the added advantage that pre-treatment of sera to remove inhibitors of haemagglutination and red cell agglutinins is unnecessary. The RIA test has potential for the large-scale screening programmes which need to be carried out if the Department of Health and Social Security recommendation, that women attending antenatal and family planning clinics be screened for rubella antibodies, is to be effectively met.

Adult