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Biomedical subjects

M W Wright

Publications and source records attributed to M W Wright.

10 recordsLinked to original sources
PubMed2001

Retinal photoreceptors of paleognathous birds: the ostrich (Struthio camelus) and rhea (Rhea americana).

Microspectrophotometry was used to determine the absorbance spectra of both rod and cone visual pigments and oil droplets from the retinae of the ostrich (Struthio camelus) and rhea (Rhea americana). Light and fluorescence microscopy of whole fresh tissue mounts were used to determine the relative numbers and distribution of oil droplets in the retinae. Both species possessed rods, double cones and four classes of single cone identified by their oil droplets. The rods had lambda max at about 505 nm, whereas three cone pigments were recorded with lambda max at 570, 505 and 445 nm. The P570 pigment was located in both members of the double cones and in a class of single cone containing an R-type oil droplet (lambda cut at 555 nm). The P505 and P445 cone pigments were found in populations of single cones containing Y-type and C-type oil droplets (lambda cut of 500 and 420 nm, respectively). The fourth class of single cone contained a T-type droplet and in the ostrich contained a visual pigment with lambda max at about 405 nm. Double cones possessed a P-type droplet in the principal member and an A-type droplet in the accessory member. The complement of visual pigments and oil droplets, and the ratio of cone types in the ostrich and rhea, are remarkably similar to those found in many groups of neognathous birds.

Animals↗
PubMed2001

Basal cell carcinoma arising in a cleft lip repair scar.

BACKGROUND: A case of basal cell carcinoma (BCC) developing in the repair scar of a cleft lip is presented. OBJECTIVE: Primary BCCs arising in surgical scars are very rare and no known reported cases exist of a BCC developing in a surgically repaired cleft lip scar. METHODS: A 69-year-old white man presented with a 5 mm primary BCC on his upper lip at the site of his cleft lip repair scar. The diagnosis was made by a tangential biopsy that showed an ulcerated BCC. RESULTS: Review of the medical literature indicates that a scar may be an independent risk factor for developing BCC. CONCLUSION: BCC may rarely arise in a cleft lip repair scar.

Aged↗
PubMed2001

Mechanisms of sunscreen failure.

Sunscreen is used as a primary strategy to prevent sunburn and later skin cancer. However, sunscreen use has paradoxically been associated with the increasing incidence of skin cancer. One explanation for this puzzling observation is sunscreen failure (sunburn in the setting of sunscreen). Our purpose was to evaluate mechanisms of sunscreen failure in a sunscreen-using population. We carried out an epidemiologic comparison of sunburned and nonsunburned beachgoers who used sunscreen. We found that men were less likely to use sunscreen than women (chi(2) = 11.3, df = 1, P = .001), and when it was used, men were less likely to apply sunscreen to all sunlight-exposed skin (chi(2) = 18.4, df = 1, P = .0001). Swimmers who used sunscreen were significantly more likely to be sunburned compared with nonswimming sunscreen users (Fisher exact test, df = 1). Sunscreen may fail to prevent sunburn if it is washed off during swimming or if it is not applied to all exposed skin. Epidemiologic studies that link sunscreen use to skin cancer should evaluate whether sunburn occurred in this setting.

Adolescent↗
PubMed1988

The choice of weapons in firearm suicides.

We report on the firearms used in 235 suicides in Sacramento County, California, during 1983-85. Handguns were used in 69 per cent of firearm suicides--65 per cent for males, 88 per cent for females--and in all such deaths among women ages 35 and older. We tested the hypothesis that the choice of firearms by persons committing suicide at home would passively reflect the reported prevalence of firearms by type in households in the region. Handguns were used more frequently (rate ratio 2.00; 95% CI = 1.68, 2.39), and rifles and shotguns less frequently than expected.

Adolescent↗
PubMed1985

The use of lipid emulsion as an intravesical medium to disperse light in the potential treatment of bladder tumors.

An obstacle to satisfactory treatment of early bladder cancer with hematoporphyrin derivative-photoradiation therapy is nonuniform illumination of the bladder mucosa. This study was done to determine the characteristics and attenuation of laser light passing through the dispersion medium. Bladder simulation was achieved with the use of 5 different sizes of round-bottom flasks. Intralipid was the dispersion medium. For each flask, 6 different concentrations of the dispersion medium were used. An Argon ion laser was used to stimulate a dye laser at 630 nm. The laser was directed toward the center of the flasks via a fiberoptic cable and energy concentration at 7 different angles was measured. We concluded that the optimal medium was a 1:100 dilution of Intralipid with water, which produced an almost uniform dispersion of light on the walls of the flask. There is a linear correlation between power as measured at the fiber tip and the amount of radiation detected on the walls of the flasks. After determining optimal concentration of medium, we calculated the amount of time needed for a desired energy (Joules/cm.2) to treat a tumor. This calculation was based on the size of the bladder and the power as measured at the fiber tip. The results indicate it is possible to treat the entire mucosa of the bladder with a uniform dose of photoradiation energy.

Fat Emulsions, Intravenous↗
PubMed1977

Behavioural and social characteristics of the patient with repeated venereal disease and his effect on statistics on venereal diseases.

The current study investigated personality characteristics and social circumstances in patients repeatedly infected with venereal diseases. An effort was made to identify characteristics that would differentiate a repeat patient (RP) from a non-repeat patient (NRP). Two studies were carried out. In the first, a group of patients from a venereal disease clinic in a large general hospital was first interviewed and then the patients were asked to complete a questionnaire. In the second study, an attempt was made to validate the findings from the first study by comparing data from RP and NRP venereal disease patients drawn from medical and social case histories from a second hospital. Results of both studies support the hypothesis that repeat patients are different from non-repeat venereal disease patients in terms of social and psychological characteristics. The significance of these findings is discussed.

Adult↗
PubMed1975

The effects of drugs on psychiatric patients' performance on the Halstead-Reitan neuropsychological test battery.

The relationship between the type and amount of psychotropic drug ingestion was evaluated for 184 psychiatric patients using a complex battery of cognitive-sensory-motor tests (Halstead-Reitan). The total patients' group included 68 psychotic patients who were being treated with either phenothiazines or "another drug," and 80 neurotically depressed patients who were taking either no drugs, phenothiazines, minor tranquilizers, tricyclic antidepressants, or sedatives. Little, if any, effect was noted in terms of psychological test performance when individual drug types were combined and considered in terms of dosage. However, upon a more specific analysis of the data, several suggestive trends occurred, demonstrating that individual drugs have variable effects and that some age groupings are more sensitive to drug effects than other groupings. As these trends were a result of a secondary analysis, further investigation was recommended in order to delineate the variables involved. For the present, this investigation has demonstrated the important influence of age and drug type variables upon patient neuropsychological test performance.

Antidepressive Agents, Tricyclic↗