Search PubMed⌕ Search

Biomedical subjects

N Jones

Publications and source records attributed to N Jones.

At least 253 records · Page 14Linked to original sources
PubMed1979

Antenatal screening in Oxford for fetal neural tube defects.

Between May 1975 and the end of 1977, 6443 antenatal patients were screened mainly between 16 and 22 weeks of pregnancy for neural tube defects (NTDs) at the John Radcliffe Hospital, Oxford, by maternal serum alpha-fetoprotein (AFP) measurement; a take-up of 72 per cent. Seventeen out of 18 (94 per cent) patients with open NTD pregnancies (9 out of 9 with anencephaly and 8 out of 9 with open spina bifida) had positive screening tests, and all except one were offered and accepted a termination of pregnancy. Two hundred and forty-five (3.8 per cent) patients with unaffected pregnancies also had positive screening tests, although only 1.4 per cent had an amniocentesis. Following ultrasonography, about 50 per cent of patients with unaffected pregnancies with positive screening tests were not offered an amniocentesis because they had a multiple pregnancy or their gestational age had been underestimated. The odds of having a fetus with an NTD among the women who had an amniocentesis was about 1 to 6 (1 to 11 for open spina bifida alone). Two apparently normal pregnancies were terminated. A survey of the acceptability of the screening programme among a consecutive sample of 73 patients who knew that they had a positive screening test revealed that all except one had no objection to screening in general, and 68 (93 per cent) wanted to be tested again in a future pregnancy. The approximate direct cost of the programme was 2 pounds to 3 pounds per patient screened, or about 1000 pounds per NTD detected (about 2200 pounds per open spina bifida detected).

Amniocentesis↗
PubMed1978

Immunological studies of testicular tissue in oligozoospermic and azoospermic patients.

Testicular biopsies from 6 oligozoospermic and 12 azoospermic patients were examined histologically and immunohistologically. Evidence of maturation arrest and of Type II allergic reactions involving tubular basement membranes was found in all oligozoospermic patients. No evidence of an immune reaction was found in 9 azoospermic patients with maturation arrest. Unilateral or bilateral germ cell aplasia with evidence of mixed Type II and III or Type III and IV reactions was present in 2 oligozoospermic and 2 azoospermic patients. The findings have been interpreted to indicate that maturation arrest and germ cell aplasia may occasionally be linked in a chain of immunological events, initiated possibly by damage to tubular basement membranes. No correlation was demonstrable between the histological and immunohistological findings and indirect immunofluorescent tests for sperm antibodies. It is suggested that testicular biopsy is a potentially hazardous procedure in the investigation of infertility, and that prepubertal testicular tissues as well as sperm be used as antigens in the immunological investigation of infertility.

Antibodies↗
PubMed1977

Distribution and persistence of hepatitis B surface antigen and antibody in a Melanesian population.

The population of Graciosa Bay, Santa Cruz, British Solomon Islands Protectorate, was tested for HBsAg and anti-HBs in 1973 and 1974. Both the antigen and antibody occurred more often in males, presumably due to a higher exposure rate. None of 28 infants under one year of age had antigen and only one of 50 individuals under two years (2%) did. The prevalence of antigenemia was higher in older children and did not decline with increasing age. This pattern is contrasted to that found in other populations which is characterized by onset during the first year and a decrease in prevalence in older age groups. The ratio of antigenemia prevalence to that of antibody is significantly higher in the population under six years of age (p less than 0.01), indicating that younger infected people tend to be asymptomatic carriers while older individuals tend to have produced antibody. Three of 28 individuals with antigen detectable by immunodiffusion in 1973 had lower levels, detectable only by reversed passive hemagglutination after one year. The age specific prevalence of anti-HBs increases to a peak of 34% in the 15-19 year age group and declines thereafter.

Adolescent↗
PubMed1977

Limited family clustering of hepatitis B surface antigen in a Melanesian population.

The entire population of Graciosa Bay, Santa Cruz, Solomon Islands, was tested for hepatitis B surface antigen (HBsAg) by reverse passive hemagglutination and antibody to HBsAg (anti-HBs) by passive hemagglutination. Analysis of the distribution of HBsAg in relatives of HBsAg carriers and non-carriers showed clustering only in children of carrier mothers. Similarly, there was no clustering of total exposure as measured by serologic tests except in children of carrier parents primarily due to the antibody and antigen of children of carrier mothers. This distribution pattern is probably due to cultural and environmental factors which increase exposure between HBsAg carriers and people who are not related to them and also reduce the amount of contact between siblings.

Antibodies, Viral↗
PubMed1976

Equal susceptibility of males and females on Santa Cruz Island to the carrier state of hepatitis B surface antigen.

Various studies have shown that hepatitis B surface antigen is detected more frequently in the blood of asymptomatic males than in that of asymptomatic females. The reason for this difference might be that males are more frequently infected than females or that males more frequently become asymptomatic carriers when they are infected. The sex distribution of hepatitis B surface antigen and antibody, as measured by reversed passive hemagglutination and passive hemagglutination, was determined in a Melanesian population. The frequency of the antigen was higher among males, but the ratio of antigen to antibody was the same in both sexes. This finding indicated that the higher frequency in males was due to a higher rate of infection rather than to a greater susceptibility of the males to the chronic carrier state.

Adolescent↗