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Biomedical subjects

M A Byrne

Publications and source records attributed to M A Byrne.

15 recordsLinked to original sources
PubMed2005

Deposition of contaminant aerosol on human skin.

Over recent years, it has been established that deposition of various types of pollutant aerosols (e.g., radioactive) on human skin can have serious deleterious effects on health. However, only few investigations in the past have been devoted to measurement of deposition velocities on skin of particles of the potentially problematic sizes. An experimental programme has shown the deposition velocities on skin of particles in the ca. 0.5-5 microm AMAD range to be high and generally associated with great variations. A series of investigations have been made to identify some of the factors that lead to this variation. Part of the variation was found to be caused by differences between individuals, whereas another part was found to be related to environmental factors. The identification of major influences on skin contaminant deposition is important in estimating health effects as well as in identifying means for their reduction.

Aerosols↗
PubMed2005

Conductance of photons in disordered photonic crystals.

The conductance of photons in two-dimensional disordered photonic crystals is calculated using an exact multipole-plane wave method that includes all multiple scattering processes. Conductance fluctuations, the universal nature of which has been established for electrons in the diffusive regime, are studied for photons, in both principal polarizations and for varying disorder. Our simulations show that universal conductance fluctuations can be observed in H(||) (TE) polarization for weak and intermediate disorder while, for E(||) (TM) polarization, we show that the conductance variance is essentially independent of sample size but strongly dependent on disorder. The probability distribution of the conductance is also calculated in the diffusive and localized regimes, and also at their transition, for which the distributions for both polarizations are seen to be very similar.

Journal Article↗
PubMed2002

Radiation dose implications of airborne contaminant deposition to humans.

In nuclear accident consequence assessment, dose contributions from radionuclide deposition on the human body have in the past generally been either ignored or estimated on the basis of rather simple models. Recent experimental work has improved the state of knowledge of relevant processes and parameter ranges. The results presented in this paper represent a first approach to a detailed assessment of doses from radiopollutant deposition on the human body, based on contaminant-specific data. Both the dose to skin from beta-emitters and the whole-body dose from gamma-emitters on body surfaces were found to give potentially significant contributions to dose. Further, skin penetration of some contaminants could lead to significant internal doses.

Air Pollutants, Radioactive↗
PubMed2000

Suction methods for assessing contamination on surfaces.

Suction sampling techniques are widely used to assess particulate contamination levels on domestic and occupational surfaces such as floor coverings, but their use for dermal exposure assessment has, to date, been limited. This paper reviews the sampling techniques commonly employed and summarises the range of sampling efficiencies reported in the literature. As there are an extremely large number of key factors influencing the recovery efficiency of suction sampling devices, it is recommended that controlled experiments are carried out to evaluate the relative significance of these factors, thus allowing inter-comparison of the data generated in field studies. As the range of applications of suction sampling devices is extensive, the harmonisation of sampling protocols is not considered to be a feasible objective.

Clinical Protocols↗
PubMed1998

Prevalence, causes and outcome of vulval pain in a genitourinary medicine clinic population.

A detailed assessment was completed on 150 consecutive new female patients attending a walk-in genitourinary medicine clinic, in order to elicit the features of vulval pain. Twenty patients (13.3%) experienced vulval pain, and of these, 15 (75%) had an infective cause demonstrated. Candidiasis was demonstrated in more than half (55%) of them and one-fifth had genital herpes. Of the 5 patients in whom no infection was present, 2 were diagnosed with the vulvar vestibulitis syndrome (VVS) following their referral to the dedicated vulval clinic.

Adolescent↗
PubMed1991

Evidence that patients presenting with dyskaryotic cervical smears should be screened for genital-tract infections other than human papillomavirus infection.

One hundred and fifty-four women with dyskaryotic cervical smears were referred for colposcopy from two distinct population groups, namely those who initially had attended a sexually transmitted disease (STD) clinic, and those who came from general practitioners and family planning and gynaecology clinics (non-STD group). They were investigated to determine the prevalence and pattern of concomitant lower genital-tract infections. The mean age in each group was 25 years. Microbiological studies revealed that 79 (51%) of the women were infected, more than one infection occurring in 16 (10%) of them. Infection was present in 40% of the non-STD group and 66% of the STD group. The pattern of infection was remarkably similar in each group. Bacterial vaginosis was the most common disease in each group and accounted for more than one-third of all infections detected. Six patients had genital warts, 15 harboured Chlamydia trachomatis and 4 had gonorrhoea. Two-thirds of those with C. trachomatis and half of those with gonorrhoea were asymptomatic. We conclude that an abnormal cervical smear is frequently a marker of concomitant lower genital tract infection. Comprehensive microbiological investigations in order to effect appropriate treatment are easily achieved on women in the STD group, but the cost may be seen as prohibitive for those in the non-STD group. For these women we suggest a less comprehensive microbiological approach that provides a compromise strategy of management.

Chlamydia Infections↗
PubMed1990

A prospective study of human papillomavirus infection of the cervix.

In a prospective study 42 women, diagnosed as having low grade cervical intraepithelial neoplasia (CIN), made a total of 281 clinic visits over a 45 month period. At each visit, they were subjected to cytological and colposcopical examination and samples were taken for human papillomavirus (HPV) DNA hybridization studies and for the detection of non-HPV infections. HPV types 16 and/or 18 were found in 25% of all the samples tested and these virus types were detected in five of six (83%) women whose lesions progressed compared to seven of 14 (50%) of those whose lesions regressed. The presence of HPV DNA was not a good prognostic indicator of progression since half of those whose disease regressed also harboured these viruses at some time. The recording of non-HPV infections almost 10 times more often in the women whose disease regressed than in those whose disease progressed could probably be accounted for by the former having a larger number of follow-up visits. Nevertheless, the significance of non-HPV infections also remains unclear.

Bacterial Infections↗
PubMed1989

The common occurrence of human papillomavirus infection and intraepithelial neoplasia in women infected by HIV.

Eighteen out of 19 women who were clinically well but infected by HIV showed abnormalities of the lower genital tract. Seven patients had intraepithelial neoplasia, histologically verified in five, involving the cervix in four, the vulva in three and the perineum in one. Lesions (clinical and/or subclinical) compatible with human papillomavirus (HPV) infection were identified in these women, as well as in 10 out of the other 11 women infected with HIV. Disease at more than one site was detected in half of the patients and would have remained covert in more than half, had colposcopy not been undertaken. Women with HIV infection are at high risk of harbouring HPV and of developing lower genital tract neoplasia.

Adult↗
PubMed1989

Value of colposcopy in sexually transmitted diseases clinic based on first year's experience.

Two hundred and thirty two patients underwent cervical colposcopy within the first year of establishing a colposcopy service in the sexually transmitted diseases clinic at St Mary's Hospital, London. Their mean age was 27 years. Cervical intraepithelial neoplasia (CIN) was identified in 68 of 81 (84%) patients whose smears showed dyskaryosis and who underwent biopsy. CIN was also detected in 14 of 41 (34%) patients who underwent biopsy and whose repeat smears were reported as giving normal results. The value of assessing two consecutive smears was evident, however, because none of the 99 patients with CIN had two normal smear results consecutively. Patients requiring treatment underwent laser ablation, which was provided in the department of gynaecology. These results show that colposcopy plays a vital part in managing patients with abnormal smears and indicate that genitourinary physicians need to give priority to developing colposcopy services in their specialty.

Adolescent↗
PubMed1989

Recognising covert disease in women with chronic vulval symptoms attending an STD clinic: value of detailed examination including colposcopy.

A vulval colposcopy clinic was established in the sexually transmitted diseases (STD) clinic of St Mary's Hospital, London, to investigate patients with chronic symptoms (mean duration 3 1/2 years). Fifty patients with a mean age of 33 were studied for 12 months, and a specific diagnosis was established for many of them. Forty complained of pruritus vulvae, 33 of dyspareunia, and 30 of vulvodynia. One or more macroscopic abnormality was seen in 29 of the women, the most common being erythema, papules, plaques, and fissures. Colposcopic abnormalities, however, were identified in 45 of the women, the most common being acetowhite epithelium in a flat, papillary, or cobblestone pattern. Biopsy specimens were obtained from 33 of the patients, and all had abnormal histological features. Those of human papillomavirus (HPV) infection were the most common, and were found in 27 specimens; evidence of vulval intraepithelial neoplasia was seen in seven and that of dermatoses in 10. Further work is required, however, before concluding that HPV was necessarily responsible for the chronic symptoms.

Adult↗
PubMed1986

The effect of interferon on human papillomaviruses associated with cervical intraepithelial neoplasia.

A double-blind, placebo-controlled, trial of leucocyte interferon showed that, contrary to previous reports, interferon had no significant effect on cervical intraepithelial neoplasia (CIN) when applied topically in a gel. DNA hybridization of cervical scrapes was used to monitor the effect of interferon on the human papillomaviruses (HPV) associated with CIN. There was, however, no significant difference in the expression of HPV 6 or 16 in the cervical epithelium of patients treated with interferon compared with those given a placebo. By using superficial cells scraped from the surface of the cervical epithelium as a source of DNA for viral studies, we were able to investigate the relation between HPV and CIN without interfering with the natural history of the disease. HPV 16 was detected in lesions which persisted while HPV 6 only was detected in one lesion that regressed. Regression was clearly associated with reduction in the number of copies of viral DNA per cell in this case. Dual infection with HPV types 6 and 16 were recorded in two patients with persistent lesions. In one patient, hybridization studies indicated that infection with HPV 16 could have occurred after infection with type 6 was established, and it is postulated that this may have changed the nature of the cervical lesion.

Adolescent↗