PubMed Health⌕ Search

Biomedical subjects

N Hallam

Publications and source records attributed to N Hallam.

18 recordsLinked to original sources
PubMed1999

The protective effect of immunisation against diphtheria, pertussis and tetanus (DPT) in relation to sudden infant death syndrome.

Epidemiological evidence indicates infants immunised against diphtheria, pertussis and tetanus (DPT) are at decreased risk of sudden infant death syndrome (SIDS). Asymptomatic whooping cough and pyrogenic toxins of Staphylococcus aureus have been implicated in the aetiology of SIDS. The objectives of the present study were: (1) to determine if the DPT vaccine induced antibodies cross-reactive with the staphylococcal toxins; (2) to determine if antibodies to the pertussis toxin (PT) and the staphylococcal toxins were present in the sera of women during late pregnancy; (3) to examine the effects of infant immunisation on levels of antibodies to PT and the staphylococcal toxins; (4) to assess the effects of changes in immunisation schedules in the UK on the incidence and age distribution of SIDS. Enzyme-linked immunosorbent assays (ELISA) were used to measure binding of rabbit or human IgG to the DPT vaccine, PT, toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxins A (SEA), B (SEB) and C (SEC). Neutralisation activity of anti-DPT serum was assessed by a bioassay for induction of nitric oxide from human monocytes by the staphylococcal toxins. Anti-DPT serum bound to the DPT vaccine, PT and each of the staphylococcal toxins. It also reduced the ability of the four toxins to induce nitric oxide from monocytes. In pregnant women, levels of IgG to PT, SEC and TSST-1 decreased significantly in relation to increasing weeks of gestation while antibodies to SEA and SEB increased. In infants' sera there were significant correlations between levels of IgG bound to DPT and IgG bound to PT, TSST-1 and SEC but not SEA or SEB. Antibody levels to the toxins in infants declined with age; sera from infants < or = 2 months of age had higher levels of IgG bound to the toxins than those older than 2 months. This pattern was observed for infants whose immunisation schedules began at 2 months of age or 3 months of age. The decrease in IgG bound to the toxins was, however, less for those immunised at 2 months. The decrease in SIDS deaths after the change in immunisation schedules was greatest in the 4-6-month age range. While DPT immunisation might prevent some unexplained infant deaths due to asymptomatic whooping cough, these data indicate that immunisation with DPT also induces antibodies cross-reactive with pyrogenic staphylococcal toxins implicated in many cases of SIDS. Passive immunisation of infants who have low levels of these antibodies might reduce further the numbers of these infant deaths.

Animals↗
PubMed1996

Vertical transmission of hepatitis C virus infection.

Since the virus responsible for non-A, non-B hepatitis was cloned in 1989, much has been learnt about the epidemiology, diagnosis and clinical spectrum of hepatitis C virus (HCV) infection. As the routes of transmission are elucidated, specific groups of children as well as adults are known to be at particular risk of infection. The women most at risk of HCV infection are those with a history of injecting drug use. Mother-to-child transmission has been documented, although the exact risk has not been quantified, and the factors influencing the risk remain to be evaluated. This article reviews current knowledge on vertical transmission of HCV, and provides some guidelines on the management of infants born to women infected with the virus.

Adult↗
PubMed1995

Emotional reactions in women attending a UK colposcopy clinic.

STUDY OBJECTIVE: To assess the emotional responses of women attending a colposcopy clinic for investigation of an abnormal cervical smear, and to elicit the women's views on the screening service and colposcopy clinic. DESIGN: Over 12 months all new attenders at a colposcopy clinic were invited to join the study. They were assessed psychiatrically four weeks before their first clinic appointment, and four weeks and 32 weeks after their first clinic appointment. SETTING: Colposcopy clinic, John Radcliffe Hospital, Oxford. PATIENTS: Of 114 women attending the colposcopy clinic for investigation of an abnormal cervical smear, 102 agreed to enter the study. MEASUREMENTS: Psychiatric symptoms were assessed with a standardised psychiatric interview, the present state examination; and with four self rated mood scales:--the general health questionnaire, the Beck depression inventory, the Leeds depression scale, and the Leeds anxiety scale. MAIN RESULTS: On all these measures, in the whole patient group, psychiatric morbidity was found to be transient and relatively minor. Thus ratings on the present state examination were not significantly higher than the rate found in a community sample of 520 women in Oxford, while on the four self rated mood scales, mean total scores were lower than the cut off value used to distinguished cases. Patient satisfaction with the colposcopy services was generally high but there was some dissatisfaction with delays. CONCLUSIONS: After an abnormal cervical smear, further investigation by colposcopy is generally associated with low levels of anxiety and depression.

Adolescent↗
PubMed1993

HIV-specific cytotoxic T-cell activity in an HIV-exposed but uninfected infant.

The factors necessary for protective immunity against HIV-1 are unknown. Important information about these factors should come from study of people at high risk of HIV infection who have not apparently become infected. Among these are the estimated 60-85% of children who may be exposed in utero or perinatally to HIV-1 but do not become infected. We observed the transient appearance of HIV-specific cytotoxic T-lymphocyte (CTL) activity in a baby born to HIV-1-infected parents, in whom all standard markers of infection remained negative. These findings suggest that HIV-specific CTLs may be a marker for recently exposed, but uninfected, individuals.

CD4-CD8 Ratio↗
PubMed1991

Prevalence of HPV cervical infection in a family planning clinic determined by polymerase chain reaction and dot blot hybridisation.

The overall prevalence of human papillomavirus (HPV) cervical infection in 131 women attending a family planning clinic was 7% (HPV 6/11, 16, 18, 31) by dot blot hybridisation, 53% (HPV 11, 16, 31) by polymerase chain reaction (PCR), and 56% by the two methods combined. HPV 16 and 18 were the commonest types (4% each) by dot blot, HPV 16 (39%) by PCR. Fifteen percent of subjects had mildly abnormal cervical cytology (grades 1A, 2A, or 3). There was no significant correlation between cytological abnormality and HPV positivity, or between cytological or HPV status and other postulated risk factors for cervical neoplasia. It is concluded that PCR is considerably more sensitive than dot blot DNA hybridisation in detecting HPV cervical infection in such a "low risk" setting, where HPV copy number may be low. Firm conclusions cannot be drawn from our results regarding a causal role for HPV or other factors in the development of cervical neoplasia.

Adolescent↗
PubMed1989

Detection and typing of human papillomavirus infection of the uterine cervix by dot blot hybridisation: comparison of scrapes and biopsies.

Paired scrapes and biopsies from 100 women attending a routine colposcopy clinic were examined by dot blot DNA hybridisation for infection with human papillomavirus (HPV) types 6/11, 16, 18, and 31; 51% of the scrapes and 50% of the biopsies were positive for HPV infection. Scrapes detected more HPV 18 (10% vs. 2%, P = less than 0.05) and HPV 31 (7% vs. 3%, not significant) than did the biopsies, but biopsies detected more HPV 16 (42% vs. 33%, not significant). Comparison of the results for each patient revealed that the correlation between scrapes and biopsies was not very close: only 34 patients were HPV-positive by both sampling methods, whereas 67 were positive if the results were combined. This report discusses the implications of these findings.

Adolescent↗
PubMed1986

Evaluation of colposcopy in the postmenopausal woman.

Cytology, colposcopy and histology findings in 121 postmenopausal and 120 premenopausal women referred to the Oxford colposcopy clinic were compared; 88% of postmenopausal and 69% of premenopausal women were referred by their general practitioners. Cervical smear reports, within the preceding 5 years, were available for 21% of the postmenopausal and 54% of the premenopausal women. Colposcopic assessment was technically unsatisfactory in 53% of the postmenopausal women because the transformation zone was not completely visible, this contributed to a cone biopsy rate of 71% in this group. Only 17% of postmenopausal women with cervical intraepithelial neoplasia (CIN) were managed with local ablative techniques compared with their use in 61% premenopausal patients overall and in over 70% of the women under 35 years. Local ablation was used in 10 of 14 women using hormone replacement therapy. The cytological false negative rate for postmenopausal Papanicolaou class III, IV and V smears was 9% but for persistent class II inflammatory smears it was 43%. Nine of 23 postmenopausal women with persistent inflammatory dyskariosis despite antibiotic or antifungal treatment were found to have colposcopic appearances of CIN and four had microinvasion or invasion. Colposcopy revealed probable microinvasive or invasive disease in 17 postmenopausal women, seven of whom had class II or III cytology.

Aged↗