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Biomedical subjects

S Seaman

Publications and source records attributed to S Seaman.

At least 19 recordsLinked to original sources
PubMed2006

Semicarbazide in Canadian bakery products.

Levels of semicarbazide were determined by liquid chromatography-tandem mass spectrometry using isotope dilution ((13)C(15)N(2)-semicarbazide) methodology, and they were measured, after hydrolysis in 0.125 M hydrochloric acid and derivatization with 2-nitrobenzaldehyde, as a sum of free and bound semicarbazide. Levels of semicarbazide in 11 bakery products, which were sampled at three time intervals from the same source, varied from not detected (<1ng g(-1)) to 560 ng g(-1). In some instances, concentrations of semicarbazide varied between batches of the same product, at times more than tenfold, suggesting that the addition of azodicarbonamide to the same product is not standardized in many baking establishments.

Azo Compounds↗
PubMed2005

Development and validation of a headspace method for determination of furan in food.

In the past furan had been found to form in foods during thermal processing. These findings and a recent classification of furan as a possible human carcinogen prompted us to develop a simple isotope dilution method for its determination in foods. We also investigated effects of furan volatility, sample matrix and partitioning of furan between water and fat constituents of sample on the analytical determination of furan. The method is based on headspace sampling of a 2 ml vial containing 1 g of sample. For analysis, samples were spiked with d(4)-furan, homogenized in a blender at 0 degree C, with water if required, and sub-sampled to vials containing sodium sulphate. After equilibration at 30 degrees C, 50 microl of headspace was injected into the split/splitless injection port of a GC/MS (EI, SIM). The method is linear in the 0.4-1000 ng/g range with a limit of detection of 0.1 ng/g.

Carcinogens↗
PubMed2004

Bayesian trio models for association in the presence of genotyping errors.

Errors in genotyping can greatly affect family-based association studies. If a mendelian inconsistency is detected, the family is usually removed from the analysis. This reduces power, and may introduce bias. In addition, a large proportion of genotyping errors remain undetected, and these also reduce power. We present a Bayesian framework for performing association studies with SNP data on samples of trios consisting of parents with an affected offspring, while allowing for the presence of both detectable and undetectable genotyping errors. This framework also allows for the inclusion of missing genotypes. Associations between the SNP and disease were modelled in terms of the genotypic relative risks. The performances of the analysis methods were investigated under a variety of models for disease association and genotype error, looking at both power to detect association and precision of genotypic relative risk estimates. As expected, power to detect association decreased as genotyping error probability increased. Importantly, however, analyses allowing for genotyping error had similar power to standard analyses when applied to data without genotyping error. Furthermore, allowing for genotyping error yielded relative risk estimates that were approximately unbiased, together with 95% credible intervals giving approximately correct coverage. The methods were also applied to a real dataset: a sample of schizophrenia cases and their parents genotyped at SNPs in the dysbindin gene. The analysis methods presented here require no prior information on the genotyping error probabilities, and may be fitted in WinBUGS.

Alleles↗
PubMed2003

Osteopontin gene and clinical severity of multiple sclerosis.

Osteopontin transcription is increased in the central nervous system of patients with multiple sclerosis and rats with experimental allergic encephalomyelitis; where expression correlates with disease severity. We typed four single nucleotide polymorphisms located in exons 6 and 7 of the osteopontin gene in a large cohort of 1056 multiple sclerosis patients and 325 controls. We did not find significant allelic differences of the screened polymorphisms between the cases and controls and there was no allelic association with disease severity. Despite strong theoretical reasons to consider osteopontin as a potential candidate, the results of our study argue against the gene being a susceptibility locus for either the development or clinical severity of MS.

Alleles↗
PubMed2003

Gamma knife stereotactic radiosurgery for unilateral acoustic neuromas.

OBJECTIVE: To evaluate the clinical results achievable using current techniques of gamma knife stereotactic radiosurgery to treat sporadic unilateral acoustic neuromas. METHODS: A retrospective review of 234 consecutive patients treated for unilateral acoustic neuromas between 1996 and 1999, with a mean (SD) follow up of 35 (16) months. Tumour control was assessed with serial radiological imaging and by the need for surgical intervention. Hearing preservation was assessed using Gardner-Robertson grades. Details of complications including cranial neuropathies and non-specific vestibulo-cochlear symptoms are included. RESULTS: A tumour control rate in excess of 92% was achieved, with only 3% of patients undergoing surgery after radiosurgery. Results were less good for larger tumours, but control rates of 75% were achieved for 35-45 mm diameter lesions. Of patients with discernible hearing, Gardner-Robertson grades were unchanged in 75%. Facial nerve function was adversely affected in 4.5%, but fewer than 1% of patients had persistent weakness. Trigeminal symptoms improved in 3%, but developed in 5% of patients, being persistent in less than 1.5%. Transient non-specific vestibulo-cochlear symptoms were reported by 13% of patients. CONCLUSIONS: Tumour control rates, while difficult to define, are comparable after radiosurgery with those experienced after surgery. The complications and morbidity after radiosurgery are far less frequent than those encountered after surgery. This, combined with its minimally invasive nature, may make radiosurgery increasingly the treatment of choice for small and medium sized acoustic neuromas.

Adult↗
PubMed2001

Estimating the relative incidence of heroin use: application of a method for adjusting observed reports of first visits to specialized drug treatment agencies.

In this paper, the authors propose a method for estimating the incidence of heroin use by adjusting reported numbers of heroin users visiting drug treatment agencies for the time lag between onset of heroin use and first treatment request (lag distribution). The adjusted incidence is relative, since it represents the number of individuals beginning heroin use in each year whose cases will be reported within 8 years of starting use. Users with longer lag times or whose cases are never reported are excluded. Utilizing data from southeastern England (1991--1998), the authors analyzed the effects of covariates (sex, age group, ethnic group, route of consumption, and year of onset of drug use) on the lag distribution. Trends in the adjusted incidence of heroin use were very different for injectors and noninjectors: Incidence among injectors seemed to be stable, while in noninjectors it increased twofold between 1991 and 1996--1997. These results must be interpreted cautiously, especially in relation to the wider context of underlying trends in the population. Potential biases derive from underreporting and from changes in the proportion of heroin users in treatment. The lag correction method adds substantially to the value of routine treatment data, at least for heroin use, and is potentially the best method for obtaining estimates of incidence.

Adolescent↗
PubMed2000

Stereotactic radiosurgery and the risk of haemorrhage from cavernous malformations.

Eighteen patients with cerebral cavernous malformations were treated with single dose of cobalt 60 source stereotactic radiosurgery. All had suffered at least one haemorrhage prior to treatment with six suffering 2, four suffering 3 and one suffering 4. Mean follow-up was 4.5 years. A total of 36 pretreatment haemorrhages occurred in 139 patient years. The first haemorrhage each patient suffered was taken as the start of observation and not included in the rehaemorrhage rate calculation. Three posttreatment haemorrhages occurred in 81 patient years of observation. The annual haemorrhage rate thus fell from 13% before to 3.7% after treatment. The odds ratio was thus 0.29 with a 95% confidence interval of (0.08-0.97), but this must be interpreted with caution because of the prereferral selection of this group of patients. Three patients developed complications of radiosurgery, two of them recovered fully.

Adolescent↗
PubMed2000

Considerations for the global assessment and treatment of patients with recalcitrant wounds.

Many factors, both intrinsic and extrinsic, may contribute to wound recalcitrance. For example, arterial circulation may be impaired by atherosclerosis, vasospastic disorders, microemboli, thromboangiitis obliterans, vasculitis, sickle cell anemia, and antiphospholipid syndrome, all of which may impair healing. Inflammatory disorders that may lead to recalcitrance include pyoderma gangrenosum and necrobiosis lipoidica. Chronic venous insufficiency, infection, diabetes mellitus, systemic malignancy, malnutrition, and exposure to pressure and shear prolong the healing process. Wounds secondary to primary skin carcinoma will not heal. Calciphylaxis, a life-threatening metabolic disorder, leads to multiple ulcerations that are especially difficult to heal. Knowledge of common factors that lead to wound recalcitrance is essential to the wound care clinician, as accurate diagnosis results in appropriate treatment. To arrive at the diagnosis, the wound care clinician must perform a thorough history and physical examination and order relevant investigative studies. Treatment is based on correction of the identified underlying condition. By utilizing a systematic approach in the management of each patient with a chronic wound, the wound care clinician increases the probability of achieving wound closure.

Bandages↗
PubMed2000

Simplifying modern wound management for nonprofessional caregivers.

Nonprofessional caregivers currently are participating in managing pressure ulcers at home. As this can be a stressful experience, innovative and easy-to-use products are needed to support caregiver confidence. A multicenter, randomized clinical trial was conducted to compare clinical performance and case of instruction of a change indicator dressing (SIG) and a hydrocolloid alginate dressing (HAD) in the management of pressure ulcers in the home and long-term care settings. SIG and HAD were randomized to 17 and 18 partial- or full-thickness pressure ulcers respectively. During five dressing changes, wound area, dressing application, maintenance, appearance, removal, wear time, ease of teaching, and caregiver understanding of each dressing's instructions were measured. Both dressings were rated highly regarding ease of teaching, ease of use, appearance, maintenance, and helpfulness in signaling the need for dressing change by both professional and nonprofessional wound caregivers. Average dressing wear time was 3.2 days for SIG and 2.7 days for HAD. Of these wounds managed in a moist environment, 6 of 17 (35%) subjects whose wounds were dressed with SIG, and 1 of 18 (6%) dressed with HAD healed during the course of the study (alpha < 0.04). Percent wound reduction in area per day of care was also greater for SIG (alpha < 0.01). Innovative dressings may help caregivers provide consistent quality pressure ulcer care and improve wound-healing outcomes.

Aged↗
PubMed1996

Basic ostomy management: assessment and pouching.

Home healthcare nurses have tremendous impact on how a patient adapts to a new ostomy. This article increases the nurse's knowledge regarding basic ostomy management by reviewing common ostomy surgical procedures, assessment of the stoma, ostomy supplies, and appliance application and by providing helpful hints for helping the patient incorporate the ostomy into everyday life.

Activities of Daily Living↗
PubMed1994

Obstructive sleep apnea.

Humans spend one-third of their lives sleeping, yet the role of this phase of the circadian rhythm is not clear. Theories postulating the purpose of sleep include the restorative theory and the humeral theory. Both theories have identified weaknesses. What is known is that chronic disruption of sleep and/or sleep deprivation causes significant physiological and psychological symptoms. These include fatigue, lethargy and daytime somnolence accompanied by irritability, memory loss, decrease in judgment and paranoia. Obstructive sleep apnea (OSA) imposes another, more life-threatening dimension for the client.

Humans↗
PubMed1993

Sleep: a reality or dream for the hospitalized adult?

Nursing research literature is examined to determine the extent of sleep loss for the hospitalized adult. Research from the patient's perspective, nurses' assessment of patient's sleep and somnographic studies are considered. Although these three methods are inconsistent in the exact extent of sleep loss, all suggest that hospitalized patients experience less sleep than their normal pattern. Reasons for patients losing sleep are explored. Environmental factors in critical care areas are the most cited reason for loss of sleep yet other reasons are suggested. Consequences of sleep loss are explored. Some nursing interventions offered in the existing literature are examined for their feasibility. Finally, directions for future research are offered from this review of the literature.

Adult↗
PubMed1989

Differences between caries levels in 5-year-old children from fluoridated Anglesey and non-fluoridated mainland Gwynedd in 1987.

Using standard epidemiological techniques, several indicators of dental health showed significantly lower levels of caries experience in 5-year-old children from fluoridated Anglesey compared with a similar group from non-fluoridated mainland Gwynedd. The mean dmft was 0.80 in Anglesey and 2.26 in mainland Gwynedd. The mainland Gwynedd children had suffered more toothache and experienced more dental extractions. This study showed that fluoridation of water supplies remains an effective and relevant public health measure, and illustrates the value of a parental questionnaire in epidemiological surveys of younger children.

Child, Preschool↗