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Biomedical subjects

A T Williams

Publications and source records attributed to A T Williams.

At least 19 recordsLinked to original sources
PubMed2005

Intrauterine tobacco smoke exposure and hyaline membrane disease amongst triplets.

We assessed the association between prenatal smoking and respiratory distress syndrome (RDS) among triplets using a population-based retrospective cohort of 12,169 triplet live births in the United States between 1995 and 1997. Analysis was conducted using the generalised estimating equation framework to adjust for intra-cluster correlations. A total of 938 cases of RDS were reported comprising 35 among smoking (7.2%) and 903 among non-smoking gravidas (7.7%). The likelihood of RDS was comparable in both smoking categories [adjusted odds ratio (OR) = 0.93; 95% confidence interval (CI) = 0.65-1.32]. The risk for RDS due to smoking diminished with declining birth weight albeit non-significantly: low birth weight (OR = 0.99; 95% CI = 0.40-2.42), very low birth weight (OR = 0.85; 95% CI = 0.39-1.86), and extremely low birth weight (OR = 0.69; 95% CI = 0.30-1.58). In conclusion, among triplet neonates, smoking during pregnancy was not associated with respiratory distress syndrome.

Birth Weight↗
PubMed2003

The development of targeted chemotherapy for CNS lymphoma-a pilot study of the IDARAM regimen.

PURPOSE: We have developed and evaluated a CNS-targeted chemotherapy regimen based on the pharmacokinetic properties of the individual drugs in the combination. PATIENTS AND METHODS: In a twin-track study, 16 patients with secondary CNS lymphoma (SCNSL) and 8 with primary CNS lymphoma (PCNSL) were treated with IDARAM which comprised idarubicin 10 mg/m(2) i.v., days 1 and 2; dexamethasone 100 mg, 12-h infusion, days 1, 2 and 3; cytosine arabinoside (ARA-C) 1.0 g/m(2), 1-h infusion, days 1 and 2; methotrexate 2.0 g/m(2), 6-h infusion, day 3 (with folinic acid rescue); and cytosine arabinoside 70 mg plus methotrexate 12 mg, intrathecally, days 1 and 8. Two cycles were delivered at 3-weekly intervals. After response assessment, patients received adjuvant cranial radiotherapy (40 Gy over 20 fractions). RESULTS: The series comprised 24 patients, 11 male and 13 female. Their median age was 53 years (range 21 to 73 years). Grade 4 neutropenia and thrombocytopenia occurred in the majority of patients treated. Of the eight PCNSL patients, seven achieved complete remission (CR). Four remained in CR at the time of this report with a median duration of follow-up of 25 months (range 11 to 42 months). Of the 16 SCNSL patients, 12 achieved CR. Seven patients remained in CR at the time of this report with a median duration of follow-up of 24 months (range 18 to 57 months). CONCLUSION: This study suggests that IDARAM is an effective regimen in both PCNSL and SCNSL and is suitable for further development and evaluation.

Adult↗
PubMed2002

Pathologists' views on consent for autopsy.

Consent to autopsy is usually obtained by a doctor other than the one who will perform the procedure. There is an argument that, for proper informed consent, a pathologist should participate. We ascertained the views of consultant pathologists in south-east England. 53 (87%) of 61 consultants responded, of whom 50 currently do autopsies. Only 2 at present participate directly in obtaining consent, and 10 of the remaining 48 expressed willingness to do so. The general view was that consent is best obtained by a senior clinician from the team that has looked after the patient. Pathologists see their primary role as to provide guidance to clinicians. Few see it as their function to obtain consent for autopsy.

Attitude of Health Personnel↗
PubMed2001

Litter burial and exhumation: spatial and temporal distribution on a cobble pocket beach.

A cobble beach (-6 diameter to -8 diameter) located on the South Wales coastline, UK, was studied over a three-month winter period to assess litter input levels. After total beach litter clearance, six surveys were conducted at consecutive spring tides which involved marking of previously unrecorded litter. The beach was soon inundated with debris, predominantly plastic beverage containers. Some marked litter was found to disappear from the beach surface, re-emerging weeks later which suggests that the potential for litter burial has been underestimated in litter research. Higher wave energies between surveys coincided with higher levels of previously unseen litter. These new inputs consisted of sea borne and exhumed litter. Items larger than the surrounding cobbles were found to work their way back to the surface of the beach after burial, smaller items remained buried. Pits dug into the cobble ridge confirmed the burial of mainly small items.

Environmental Monitoring↗
PubMed2001

A statistical riverine litter propagation model.

A statistical riverine litter propagation (RLP) model based on importance sampling Monte Carlo (ISMC) simulation was developed in order to predict the frequency distribution of certain litter types in river reaches. The model was preliminarily calibrated for plastic sheeting by a pilot study conducted on the River Taff, Wales (UK). Litter movement was predominantly controlled by reach characteristics, such as vegetation overhang and water-course obstructions. These affects were modeled in the simulations, by utilizing geometric distributions of river reaches in the time domain. The proposed model satisfactorily simulated the dosing experiments performed at the River Taff. It was concluded from the preliminary calibrations that, the RLP model can be efficiently utilized to portray litter propagation at any arbitrarily selected river site, provided that the stream flows and reach characteristics are calibrated by representative probability distributions of similar sections. Therefore, the RLP model can be considered as a new statistical technique that can predict litter propagation in river sections.

Calibration↗
PubMed2001

The impact of a 10-year audit cycle on blood usage in a district general hospital.

As clinical governance moves from concept to practice, it is emerging as a realistic strategy to promote and improve quality within the National Health Service, as well as satisfying the demand for external accountability. In the context of blood transfusion, the area of responsibility encompasses product liability, as well as efficient use of blood as a resource and transfusion as an appropriate clinical response. Clinical governance may be a modern catch phrase, but the principles it enshrines have long been established within blood transfusion, and in other aspects of haematology. Here, an audit cycle comprising four audits over a 10-year period to monitor the use of cross-matched blood in a large district general hospital is described. Initially, blood use was considered by hospital site, and by the surgical procedure for which it was requested. Later, the scope of the audit was expanded to consider usage by individual consultant. A standard of efficient use of cross-matched blood was taken to be a cross-match to transfusion ratio of < 1.5. The information was reviewed by the hospital transfusion committee, who have a key role in co-ordinating and assessing the practice of transfusion within a hospital. In this hospital, audit has been one of the main tools for improving practice, in particular by enabling the implementation and continuous revision of a maximum blood order schedule. Further, as the process of audit has developed, problem areas have been highlighted, and strategies to improve usage have been brought in with encouraging results. The audit is now being expanded again to include a greater focus on usage of cross-matched blood in the nonsurgical setting.

Blood Loss, Surgical↗
PubMed1995

Upregulation of integrin expression in benign vulvar warts.

Benign anogenital warts demonstrate features both of hyperproliferation and of aberrant differentiation associated with human papillomavirus (HPV) infection. The expression of integrins has been examined in normal vulvar epithelium and benign vulvar warts to determine whether HPV infection is associated with changes in integrin expression, either during terminal differentiation or among the proliferating cell population. The expression of integrins in normal vulvar epithelium was similar to that seen in the epidermis, with little expression of alpha 1 and expression of alpha 2, alpha 3, and beta 1 at the periphery of basal cells. In vulvar wart epithelium, alpha 1 was not significantly expressed, but upregulation of alpha 2, alpha 3, and beta 1 was seen at the periphery of cells throughout the basal and spinous layers. In addition, alpha 2 staining was greater at foci along the basal layer of normal vulva, whilst such heterogeneity was not detected in wart sections. Expression of beta 4 and alpha V was confined to the basal and lateral aspects of normal basal cells, but expressed at the periphery of basal cells and to a lesser extent in epibasal and spinous layers of warts. The observed differences in integrin expression are consistent with those reported in other hyperproliferative epithelia.

Condylomata Acuminata↗
PubMed1995

Development and characterization of a novel xenograft model permissive for human papillomavirus DNA amplification and late gene expression.

Human papillomaviruses (HPVs) are important human pathogens associated with a range of epithelial neoplasia. The rising incidence of HPV infection and association of HPV with malignancy has led to increased interest in appropriate management of these infections. Development of new therapies for viral warts has been frustrated by the lack of availability of models permissive for viral replication. Here we describe the development of HPV-severe combined immunodeficient mouse model which reproduces mature HPV-infected epithelia. Grafting of anogenital and laryngeal papillomas harbouring either HPV-6 or HPV-11 resulted in the formation of a differentiated neo-epithelium exhibiting the hallmark features of HPV infection including basal hyperplasia, acanthosis and koilocytosis. The reformed warty epithelium contained amplified HPV DNA and expressed capsid protein in the differentiated layers. A striking feature is the production of macroscopic papillomata in an anatomically relevant and accessible site, providing a system of particular relevance for the temporal evaluation of developing lesions and selection of antiviral agents.

Animals↗
PubMed1994

Retention of low copy number human papillomavirus DNA in cultured cutaneous and mucosal wart keratinocytes.

Cultured wart keratinocytes have previously been described as having a limited proclivity to maintain episomal human papillomavirus (HPV) DNA. To investigate the nature of episome loss, and to determine keratinocyte-specific factors involved in it, we have examined a large series of anogenital and oral wart keratinocyte cultures, tracing episomal copy number with culture passage. We report that a higher proportion of oral wart keratinocytes maintain episomal HPV DNA to first passage (70% compared with 37% of anogenital wart cultures) when screened by slot blot hybridization. Furthermore, oral wart keratinocytes maintain episomal HPV copy through a greater number of passages (60% positive at passage 2 compared with 2% of anogenital wart cultures) with this technique. When anogenital cultures were examined at first passage for HPV infection by PCR with Southern blot hybridization of the product, a further 34% were found to be HPV-positive. To determine the mechanism of loss of episomal DNA from these cultures we examined the relative HPV copy number in cells which adhered to the culture vessel following passage and in those which did not adhere. Those which remained floating contained episomal HPV at high copy number whereas those which adhered were negative by slot blotting. The adherent cells, however, remained positive by PCR at subsequent passages until senescence. We conclude that a subpopulation of HPV-positive keratinocytes may be maintained in culture through serial passage until senescence.

Blotting, Southern↗
PubMed1993

Malignant transformation of cutaneous lesions in renal allograft patients: a role for human papillomavirus.

Renal allograft recipients are at greatly increased risk of developing squamous cell carcinomas. As these frequently arise adjacent to areas of multiple viral warts, we have investigated a possible role for human papillomavirus in malignant transformation within this population. We established, as primary cultures, keratinocytes from 24 lesions of varying degrees of squamous atypia from 9 patients. Ten of 14 cultures screened for the presence of episomal human papillomavirus DNA were positive using a mixed probe for cutaneous human papillomaviruses, although episomal copy was universally lost with continued passage. Three cultures, 2 of which were derived from malignant tissue and 1 from a benign lesion, were positive when screened with a probe for potentially oncogenic human papillomavirus DNAs 5 or 8. Both positive cultures of malignant origin exhibited extended lifespan and have been briefly characterized by morphology and growth requirements.

Biopsy↗
PubMed1992

Serum osteocalcin in the management of myeloma.

We have measured serum osteocalcin, a vitamin K-dependent glycoprotein synthesised by osteoblasts in 62 patients, 49 with myeloma, 26 at presentation and 23 previously treated, 7 with Waldenstrom's macroglobulinaemia (WM), and 6 with monoclonal gammopathy of uncertain significance (MGUS). Osteocalcin levels were normal in WM and MGUS. High values were found in 5/26 (19%) patients with myeloma at presentation. There was no relationship between serum osteocalcin and stage of disease. Osteocalcin was normal in all patients in plateau phase, falling to low levels in relapsed patients who failed to respond to further treatment. Serum osteocalcin may be a useful indicator of bone metabolism in myeloma.

Adult↗
PubMed1992

Concurrent benign teratoid medulloepithelioma and pineoblastoma.

Teratoid medulloepithelioma of the ciliary body is a rare tumor usually occurring in young children. Primary tumors of the pineal gland are also quite rare and have a similar age distribution. We report the case of a 2-year-old girl who had a leukocoria of the right eye. Cataract surgery was performed; however, the patient developed a total retinal detachment refractory to treatment. She eventually developed early changes of phthisis bulbi and underwent an evisceration. Histopathologic examination revealed a benign teratoid medulloepithelioma containing islands of hyaline cartilage and rhabdomyoblasts. During the course of her evaluation, a pineoblastoma was discovered and surgically excised. While the association of pineal tumors with retinoblastomas has been well established, no such association has been reported for medulloepitheliomas. To our knowledge, this is the first recorded case of a benign teratoid medulloepithelioma occurring concurrently with a pineoblastoma.

Brain Neoplasms↗
PubMed1990

A double-masked three-month comparison between 0.25% betaxolol suspension and 0.5% betaxolol ophthalmic solution.

In 352 patients with primary open-angle glaucoma or ocular hypertension, a multicenter double-masked, parallel-group clinical study compared the effects on intraocular pressure and ocular comfort of 0.5% betaxolol ophthalmic solution, a cardioselective beta-adrenergic blocking agent, with 0.25% betaxolol suspension. With twice-daily dosages, baseline intraocular pressure was significantly reduced (P = .0005), with no significant difference between the two groups, at Week 2 and at Months 1, 2, and 3. Further, the prevalence of ocular discomfort upon topical instillation was significantly lower for 0.25% betaxolol suspension than for 0.5% betaxolol solution (P = .0005).

Administration, Topical↗
PubMed1990

Chylous ascites should suggest constrictive pericarditis even in a patient with cirrhosis.

Chylous ascites, a milky, high triglyceride fluid is usually found in patients with lymphatic obstruction from malignancy. We describe a patient with cirrhosis who developed constrictive pericarditis and chylous ascites. Long-standing portal hypertension compounded by elevated central venous pressure provided several pathophysiologic contributions to the formation of the chylous ascites. Chylous ascites even in a cirrhotic requires prompt assessment for conditions leading to elevated central venous pressure.

Chylous Ascites↗