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Biomedical subjects

R Marks

Publications and source records attributed to R Marks.

At least 55 records · Page 3Linked to original sources
PubMed2000

Gas-phase mercury in the atmosphere over the southern Baltic Sea coast

Results of atmospheric total gaseous mercury (TGM) measurements performed at two Baltic Sea coastal stations, Peninsula Hel (Poland) and Preila (Lithuania), from June 16 to August 11, 1997, are presented. High time-resolution data were obtained by using automated atomic absorption mercury vapor analyzers (Model Gardis-1A). Analysis of TGM concentration data (directional distribution, correlation with meteorological parameters, diurnal variability) detected the Baltic sea, in particular its southern part and Gulf of Gdansk, as the main gaseous mercury source for the region during the summer months. The source seemed to be activated by solar radiation, air temperature, and, probably, wind.

Journal Article↗
PubMed2000

The prevalence of seborrheic keratoses in people aged 15 to 30 years: is the term senile keratosis redundant?

BACKGROUND: Seborrheic keratoses (SKs) are common skin lesions that have been shown to occur with increasing age, although the age of onset is not well recorded. OBJECTIVE: To determine the prevalence, nature, and distribution of SKs in young people. METHODS: One hundred seventy people aged 15 to 30 years were given a total body examination during which the presence, number, site, and size of SKs were recorded. Biopsy specimens were taken from the first 22 people who had lesions clinically diagnosed as SKs. Data on age, skin type, eye color, and hair color were recorded for all respondents. RESULTS: Forty (23.5%) of 170 respondents had at least one SK, with no significant difference between the sexes. There was an increase in prevalence with age from 15.7% in 15- to 19-year-olds to 32.3% in those aged 25 to 30 years. The size of the SKs also increased with age. A total of 77.5% of SKs were found on the trunk and 22.5% on the limbs, head, and neck. There was no correlation between SKs and any particular hair and eye color or skin type. CONCLUSIONS: These findings confirm that SKs are common lesions in young Australians, appearing in a substantial proportion of people younger than 30 years. The term senile keratosis is no longer appropriate for these lesions.

Adolescent↗
PubMed2000

Safety and efficacy of 1 year of tacrolimus ointment monotherapy in adults with atopic dermatitis. The European Tacrolimus Ointment Study Group.

OBJECTIVE: To investigate the safety and efficacy of using 0.1% tacrolimus ointment for long-term treatment of atopic dermatitis. DESIGN: Open-label, noncomparative study with 6 to 12 months of follow-up. SETTINGS: Outpatient departments in 30 study centers in 11 European countries. PATIENTS: We enrolled 316 patients aged 18 years and older with moderate to severe atopic dermatitis, 200 for 6 months and 116 for 12 months; 77.5% of patients completed the study. INTERVENTION: Twice-daily application of 0.1% tacrolimus ointment on all affected skin. Visits were scheduled on day 1; after 1, 2, and 4 weeks of treatment; and monthly thereafter. MAIN OUTCOME MEASURES: Safety assessments included monitoring of adverse events, clinical laboratory values, and tacrolimus blood concentrations. Efficacy end points included a combined score (modified Eczema Area and Severity Index) and an investigator's global assessment. RESULTS: Local irritation, adverse events such as burning sensation (47% of patients), pruritus (24% of patients), and erythema (12% of patients) were common but tended to occur only when initiating treatment. Laboratory values showed no marked changes over time. Systemic absorption was minimal, with the maximum tacrolimus blood concentration being less than 1 ng/mL in 76% of patients. All efficacy end points showed improvement. The mean (SD) modified Eczema Area and Severity Index score was 23.7 (12.6) at day 1, 13.5 (11.3) at week 1, 6.1 (9.2) at month 6, and 6.1 (8.1) at month 12. Marked or excellent improvement or clearance of disease was reported in 54%, 81%, and 86% of patients at week 1, month 6, and month 12, respectively. CONCLUSION: Up to 1 year of tacrolimus ointment use was safe and effective in patients with atopic dermatitis. Arch Dermatol. 2000;136:999-1006

Administration, Topical↗
PubMed2000

Population-based surveys on the frequency of common skin diseases in adults--is there a risk of response bias?

Population-based surveys on the frequency of common skin diseases are important in determining the health needs of a community. As they rely on voluntary presentation, there is a risk of response bias which may compromise the quality of the data obtained. The aim was to determine in what way and to what degree response bias may occur in a population-based survey on the frequency of common skin diseases in adults. A follow-up study was conducted on 1043 out of 2500 adults who did not attend for examination as part of a randomized population-based survey on the frequency of common skin diseases amongst adults in Maryborough, Central Victoria, Australia. Nonrespondents were more likely to be at the extremes of age, retired, unemployed and less likely to report that they had a history of skin disease than the respondents. Subsequent examination of a sample of the nonrespondents revealed they were more likely to have skin cancers and Campbell de Morgan angiomas than the respondents. These differences cannot be fully explained on the basis of an age-related response bias alone. Response bias is a risk in population-based surveys of common skin diseases which rely on voluntary presentation. Some attempt should be made to sample the nonrespondents in these surveys to determine the nature and extent of any bias and to adjust for it, if necessary.

Adult↗
PubMed2000

Simple horizontal averaging programme enables shade correction for image analysis in psoriasis.

Computer-assisted area measurement of skin lesions would be useful for the assessment of disease severity. Difficulties can be encountered, however, when lesions cannot simply be separated using the normal threshold tool of an image analyser. Owing to body curvature, peripheral sites are usually shadowed. To obtain a well-fitting curved line to account for body curvature-induced glare and shadow, we devised a simple C-programme for averaging neighbouring pixels on the same horizontal line. An image was captured from a colour slide to the image analysis system. C++ was used for programming. Execution of the averaging programme with the original image resulted in a background brightness image file. When this was subtracted from the original image, the lesions were easily detected using the standard threshold tool and the percentage of area involved was calculated. This method is sufficiently accurate for the assessment of disease severity.

Humans↗
PubMed2000

Epidemiology of melanoma.

Melanoma incidence and morality rates are increasing in most countries throughout the world where they are being recorded. The annual incidence rates have increased in the order of 3-7% in fair-skinned populations in recent decades. The mortality rates have increased at a rate lower than for incidence. This has been attributed to educational programs designed to improve the early detection of melanoma, as the treatment of melanoma has not changed substantially in recent decades. There has been a decrease in the thickness of melanoma with an increasing proportion of thin melanomas at diagnosis. Causation of melanoma is a combination of constitutional risk factors of which skin colour is the major factor. The presence and number of common acquired and dysplastic melanocytic naevi is also a major constitutional risk factor in fair-skinned people. The only environmental risk factor that has been shown consistently is exposure to sunlight, particularly large doses of sunlight sufficient to cause sunburn in childhood that will be remembered many years later. However, recreational activity leading to sunburn in adulthood is also associated with risk. To date, no other environmental factors have been shown epidemiologically to be clearly associated with risk of melanoma. Recent epidemiological data from some studies suggesting that there is an increased risk of melanoma in sunscreen users requires further explanation.

Humans↗
PubMed2000

What is heartburn worth? A cost-utility analysis of management strategies.

OBJECTIVE: To determine the best treatment strategy for the management of patients presenting with symptoms consistent with uncomplicated heartburn. METHODS: We performed a cost-utility analysis of 4 alternatives: empirical proton pump inhibitor, empirical histamine2-receptor antagonist, and diagnostic strategies consisting of either esophagogastroduodenoscopy (EGD) or an upper gastrointestinal series before treatment. The time horizon of the model was 1 year. The base case analysis assumed a cohort of otherwise healthy 45-year-old individuals in a primary care practice. MAIN RESULTS: Empirical treatment with a proton pump inhibitor was projected to provide the greatest quality-adjusted survival for the cohort. Empirical treatment with a histamine2 receptor antagonist was projected to be the least costly of the alternatives. The marginal cost-effectiveness of using a proton pump inhibitor over a histamine2-receptor antagonist was approximately $10,400 per quality-adjusted life year (QALY) gained in the base case analysis and was less than $50,000 per QALY as long as the utility for heartburn was less than 0.95. Both diagnostic strategies were dominated by proton pump inhibitor alternative. CONCLUSIONS: Empirical treatment seems to be the optimal initial management strategy for patients with heartburn, but the choice between a proton pump inhibitor or histamine2-receptor antagonist depends on the impact of heartburn on quality of life.

Anti-Ulcer Agents↗
PubMed2000

The efficacy, safety and tolerance of calcitriol 3 microg/g ointment in the treatment of plaque psoriasis: a comparison with short-contact dithranol.

OBJECTIVE: A comparison of efficacy, safety and tolerance of a twice-daily application of calcitriol 3 microg/g ointment with dithranol cream. METHODS: The study was an 8-week, prospective, randomised, open, parallel-group trial with 114 patients. Subjects received either 3 microg/g calcitriol ointment (twice daily) or 0. 25-2% dithranol cream (once daily for 30 min). Results were measured using global improvement, global severity, PASI, quality of life (QOL) and Psoriasis Disability Index scores. Safety was determined from reports of adverse events and blood chemistry analysis. RESULTS: At final assessment, calcitriol and dithranol were comparably efficacious. Skin irritation was reported by 5% of calcitriol and 72% of dithranol patients. Patients rated QOL and overall acceptability of calcitriol more highly. CONCLUSIONS: Twice-daily calcitriol ointment (3 microg/g) is equally effective as a once-daily, short-contact dithranol regimen. However, calcitriol is better tolerated than dithranol, and provides a better QOL and a greater patient acceptability.

Administration, Topical↗
PubMed2000

Seeing through the stratum corneum.

The stratum corneum (SC) provides a vital barrier membrane between the external environment and the vulnerable internal tissues of the skin. It impedes the flow of water, the penetration of xenobiotics, and invasion of pathogenic micro-organisms. It also has protective capacity against ultraviolet radiation and thermal injury. As routine histopathology provides a misleading picture of a disorganized and shadowy SC, we would recommend the skin surface biopsy technique. This painless technique is easy and reliable in obtaining information from the SC. It demonstrates the geometric patterns of the surface, the openings of the eccrine ducts and hair follicles. The skin surface biopsy technique is also ideal for the investigation of the in situ microbiology of skin. Staining with periodic acid Schiff reagent makes it possible to see ringworm fungi, pityriasis versicolor, candida species, or erythrasma micro-organisms. Scanning electron microscopy can be employed when the higher magnification is needed. Histochemical applications include silver staining for melanin particle, potassium ferricyanide staining for blood pigments and lipid staining with Sudan red, for sebum. The rate of movement of topically applied drugs into the skin can be measured using the skin surface biopsy technique. The concentration of radiolabelled drugs can be counted and compared. Comedogenicity and DNA analysis are other applications of this non-invasive technique.

Biopsy↗