Selective photothermolysis: contribution to the treatment of flat angiomas (port wine stains) by laser

Since 1962, lasers have been used in dermatology and have become the first choice in the treatment of superficial, vascular ectasia. Lasers are unique sources of light; they are coherent, monochromatic, collimated and intense. By careful selection of wavelength, pulse duration, and intensity, it is often possible to selectively confine a laser effect to a specific histologic structure in tissue, depending upon the tissue properties. The ideal treatment of Port Wine Stains (PWS) should irreversibly damage the ectatic vessels but minimize heating of the epidermis and superficial dermis. A theory, called selective photothermolysis, predicts the optimal combination of laser parameters of achieving this ideal treatment of PWS to be a wavelength of 577 nm, a pulse duration of 0.35-10 msec, and an energy per surface area of about 7-8 J/cm2. Laser wavelength: The wavelength of 577 nm is preferred because it: maximizes the selective absorption by hemoglobin, minimizes absorption by epidermal melanin, provides sufficient depth of penetration in the blood to coagulate 0.1 mm vessels allows penetration of light into dermis up to 1 mm. Laser pulse duration: A pulse-width in the range of 0.35-10 msec allows the temperature elevation to be uniform inside the vessel and to be confined to the vessel area. Shorter pulses superheat the red blood cells causing explosive boiling and hemorrhage. Longer pulses allow heat to diffuse away from vessels, requiring greater energies per pulse to achieve vessel damage. An increased energy per pulse increases the risk of excessive damage to surrounding tissue.(ABSTRACT TRUNCATED AT 250 WORDS)     

Genotyping of Chlamydia trachomatis in Urine Specimens Will Facilitate Large Epidemiological Studies

The serovars of Chlamydia trachomatis-positive urine specimens (n = 81; as detected by PCR and ligase chain reaction) were successfully analyzed in 94% of cases by omp1 PCR-based RFLP analysis. The use of urine specimens and this simple and sensitive typing method will greatly facilitate epidemiological studies of C. trachomatis serovar distribution in asymptomatic C. trachomatis infections in both females and males.     

Assessing community attitudes toward medical practitioner authority

Abstract: Despite the widespread belief that medical authority is under increasing challenge, no adequate research instrument has been available to measure relevant community attitudes. This paper reports the development of the Attitude Toward Medical Practitioners Scale (the AMPS). Samples of Australians (in total N > 1000) completed the AMPS, using three different procedures. The reliability of the scale, assessed by coefficient alpha, ranged from 0.80 to 0.86. A principal component analysis of the AMPS yielded loadings on each item exceeding 0.3 on the first unrotated factor; subsequent varimax rotation revealed dimensions associated with critical attitudes to doctors and evaluations of doctors' interpersonal competence and technical expertise. Positive and significant correlations between the AMPS and one measure of the General Attitude toward Institutional Authority (GAIAS) strongly suggested that the scale is consistent with generalised evaluations of community authorities. The specific validity of the AMPS was supported for each of three samples, using as validating criteria respondent ratings of the last doctor visited, satisfaction with the consultation and reported compliance with the doctor's advice. Significant improvements were found in the prediction of each of these criteria by the addition of the AMPS to contributions made by the GAIAS and the demographic variables, age and sex. The AMPS is an appropriate measure for assessing community attitudes towards medical practitioners conceived as institutional authorities, at least in the Australian context.     

The Effect of High-Dose Ascorbate Supplementation on Plasma Lipoprotein(a) Levels in Patients With Premature Coronary Heart Disease

Study Objective . To determine the efficacy of high-dose ascorbate supplementation in lowering lipoprotein(a) [Lp(a)] levels in patients with premature coronary heart disease (CHD). Design . Randomized, double-blind, placebo-controlled trial. Setting . Outpatient clinic. Patients . Forty-four patients with documented premature CHD. defined as confirmed myocardial infarction and/or angiographically determined stenosis of 50% or greater in at least one major coronary artery before age 60 years. Interventions . Patients were block randomized on the basis of age, gender, and screening Lp(a) concentrations to receive ascorbate 4.5 g/day or placebo for 12 weeks. Measurements and Main Results . High-dose ascorbate was well tolerated and produced a marked elevation in mean plasma ascorbate levels (+1.2 mg/dl; p<0.001). Multiple linear regression analysis revealed no significant effect of supplementation on postintervention Lp(a) levels (p=0.39) in a model that included treatment group assignment, and baseline Lp(a) levels. Conclusions . Our findings do not support a clinically important lowering effect of high-dose ascorbate on plasma Lp(a) in patients with premature CHD.     

To what extent does IQ 'explain' socio-economic variations in function?

Background  

The aims of this study were to examine the extent to which higher intellectual abilities protect higher socio-economic groups from functional decline and to examine whether the contribution of intellectual abilities is independent of childhood deprivation and low birth weight and other socio-economic and developmental factors in early life.