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Biomedical subjects

A P Kushelevsky

Publications and source records attributed to A P Kushelevsky.

16 recordsLinked to original sources

Safety of solar phototherapy at the Dead Sea.

BACKGROUND: Climatotherapy at the Dead Sea is effective for patients with psoriasis, atopic dermatitis, vitiligo, and other diseases. Although impressive improvement has been reported for patients with psoriasis, with a clearance rate of more than 80% after a 4-week stay, questions regarding the safety of this treatment have arisen. OBJECTIVE AND METHODS: We compare the mean UVB radiation intensities absorbed by psoriatic patients undergoing a 4-week climatotherapy under supervision at the DMZ Rehabilitation Clinic of Ein-Bokek (The Dead Sea, Israel), with similar climatotherapy studies in Sweden and Switzerland. We also compare the climatotherapy radiation dosages with the UVB intensities absorbed by psoriatic patients in radiation cabins at seven university clinics. RESULTS: According to our individually computerized DMZ protocol, a psoriasis patient with skin type IV is exposed during a 4-week climatotherapy to a mean 3.11 J/cm2 (148 MED) of UVB, similar to that in Sweden and Switzerland. The range of the in-clinic annual phototherapy in the seven medical centers studied varied from 1.17 to 37.80 J/cm2 (56 to 1800 MED). CONCLUSION: When all relevant factors are taken into account, the mean UVB exposure dose at the Dead Sea is one of the lowest reported for clearance of psoriatic plaques.

Humans↗

Intercomparison of global, ultraviolet B and A radiation measurements in the Dead Sea region (Ein Bokek) and Beer Sheva.

Thousands of patients suffering from psoriasis have been treated successfully in the Dead Sea area by climatological methods, without medication. This high rate of success, measured in terms of partial to complete plaque clearance and reported to exceed 85% after 3-4 weeks of treatment, has been assumed to be associated with a unique ultraviolet (UV) radiation environment present in the Dead Sea region. In order to broaden our knowledge of the UV radiation environment at the Dead Sea, continuous monitoring of UV (both B and A) and global radiation has recently been initiated at two sites--Ein Bokek (located in the vicinity of the Dead Sea 375 m below mean sea level) and Beer Sheva (315 m above mean sea level)--to facilitate an intercomparison of their respective radiation intensities. The results of the first year of a detailed study of the global, UVB and UVA radiation intensities measured at both sites are summarized and reported in terms of the monthly average daily, average midday (11:00-13:00) and the corresponding maximum values. The radiation data for clear days (based upon the absolute magnitude of the global radiation) were also analyzed to perform an intercomparison between Ein Bokek and Beer Sheva for a winter month and a summer month for which all three types of radiation data were available at both sites.

Climate↗

Sustained decrease of blood pressure in psoriatic patients during treatment at the Dead Sea.

The diastolic and systolic blood pressure of 1366 psoriatic patients, treated at the Dead Sea for a period of 4 weeks, was monitored from the day following their arrival. The patients were divided into three categories: (a) psoriatics on antihypertensive medication; (b) psoriatics not receiving antihypertensive medication, but whose initial diastolic blood pressure equaled or exceeded 90 mmHg, and (c) psoriatics with normal blood pressure (diastolic pressure lower than 90 mmHg). A paired t-test revealed that the systolic blood pressure of the two hypertensive groups (a and b) dropped by an average of 22 mmHg, and the diastolic blood pressure dropped by 11 and 16 mmHg, respectively. The drop was evident 2 days after their arrival, and leveled off only after 2 weeks. A similar drop in systolic blood pressure was observed in normotensive psoriatics. On the basis of this study it may be concluded that high blood pressure is not a contraindication for the treatment of psoriasis at the Dead Sea.

Adult↗

[Skin cancer risk of Israeli workers exposed to sunlight].

To assess the number and types of workers occupationally overexposed to sunlight, we interviewed a national sample of 450 employers in occupational categories involving outdoor work and 5000 of their workers. The workers were assigned to 5 overall risk levels, according to combinations of skin sensitivity to ultraviolet radiation (UVR), total weekly hours of outdoor occupational sun-exposure between 0800 and 1400, and percent of skin surface exposed during outdoor work in the summer. Based on this information it was estimated that out of a total of 379,000 Israeli workers in outdoor occupations, 167,000 (44%) are at increased risk for skin cancer (risk levels 1-3) due to occupational exposure to solar UVR. Their estimated lifetime skin cancer risk is 1.5- to 20-fold higher than that of workers at low or minimal risk levels (4-5). The characteristics of those interviewed with regard to occupation, duration of solar exposure, demographic traits, geographic location, degree of risk awareness and protective measures undertaken, provide a data base for effective intervention to reduce the hazards of occupational solar exposure in Israel. We estimate that an appropriate preventive program may reduce skin cancer in Israeli men to half its current rate.

Humans↗

Skin type, hair color, and freckles are predictors of decreased minimal erythema ultraviolet radiation dose.

In a group of 190 white healthy subjects the skin type classification method was found valuable for differentiating subgroups with various degrees of sun sensitivity (except for 33% with borderline or unclassifiable skin type). Sun-sensitive skin types I and II were significantly more common among persons with light hair color or freckles, or both (p less than 0.001). In each skin type category the proportion of subjects with a minimal erythema dose (MED) lower than the median MED of the entire group (%LMED) decreased significantly with increasing skin type number, and distinguished between skin types I through III better than did their mean MED values. Independent predictors of %LMED were skin type and hair color. The contribution of freckles to %LMED was skin type dependent. Age, sex, or eye color had no independent effect on %LMED. The association of skin types I and II, red or blond hair, and freckles with decreased MED may reflect genetically controlled predominance of pheomelanin (a photosensitizing molecule) in the skin of subjects with these phenotypes.

Adult↗

A more reliable index of sunscreen protection, based on life table analysis of individual sun protection factors.

The efficacy indices of two representative sunscreen preparations were determined using life table analysis of individual sun protection factors (SPF), obtained by exposing a group of subjects to ultraviolet radiation (UVR) doses from 4 to 20 multiples of the control minimal erythema dose (MED). The ultimate efficacy index is expressed as the UVR dose under which a selected percentage of the population is safely protected by a sunscreen. This method takes into account several sources of bias in the current test procedure, in particular the considerable variability in individual responses. It also takes into account subjects in whom the MED of the protected skin is either higher or lower than the range of challenge doses to which they were exposed, thereby increasing the effective sample size. This method provides a more precise and comprehensive index of sunscreen protection, and enables statistical comparison of different preparations, or of the effect of other factors on their efficacy.

Actuarial Analysis↗

Efficacy of topical sunscreen preparations on the human skin: combined indoor-outdoor study.

The sun protection factors (SPF) of 35 commercially available sunscreen preparations were tested on human skin under various conditions. Five distinct groups of products, ranging from minimal (SPF 2 to less than 4) to ultra sun protection (SPF 15 to greater than 19) were evaluated. Claimed SPF values were not always consistent with those obtained in our tests. Substantivity studies of a randomly selected group of sunscreen preparations during the hot, highly humid Israeli summer showed mean SPF reductions of 47 and 60%, respectively, following exercise-induced sweating or a 20-min swim. Judicious selection and use of an appropriate sunscreen preparation according to individual skin type or life-style, as well as the introduction of strict testing and labeling regulations, are essential measures for reducing the risk of sun-induced skin cancer and malignant melanoma in Israel.

Adult↗

The bleaching of the bacteriorhodopsin chromophore by ionizing radiation.

The visible chromophore of bacteriorhodopsin, BR(570), undergoes progressive bleaching when subjected to 60CO gamma-irradiation. The low G-value for bleaching confirms that the site of the chromophore is highly protected. Positive and negative circular dichroic (CD) bands associated with the chromosphone undergo concomitant decrease in a manner which is consistent with two independent chromophores rather than exciton coupling between neighbouring chromophoric site.

Bacteriorhodopsins↗

Ultraviolet measurements at the Dead Sea and at Beersheba.

Comparative ultraviolet (UV) spectral measurements of direct and scattered sunlight, between 300 and 400 nm, reaching the Dead Sea and Beersheba were made. It was found that the sunlight reaching Beersheba is at least twice as high in UV content as that reaching the Dead Sea. The UV content of the sunlight reaching the Dead Sea in the erythemal band (290 to 330 nm) is particularly low. The implications for heliotherapy are discussed.

Health Resorts↗

Climatotherapy of psoriasis and hypertension in elderly patients at the Dead-Sea.

The responses of various age-groups of psoriatic patients to a four-week period of climatotherapy at the Dead-Sea was compared in three separate studies. In the first study, plaque clearance following climatotherapy was evaluated in a group of 688 psoriatics, as a function of age, sex and duration of the disease. Neither the age of the patient when treated, nor the duration of the disease, appeared to influence the degree of plaque clearance. However, when the age at onset of the disease was evaluated as the comparative parameter-a decrease in the rate of response with increasing patients' age was recorded. In the second study, the type and incidence of side effects after climatotherapy was studied in 502 patients aged over 65, and in more than 4,500 younger psoriatics. There was no difference in the type and frequency of side effects between the two age-groups. The most frequent side effects were: slight sun burn (8.2%), sun allergy (5.0%), common cold (3.4%), leg oedema (2.0%), diarrhea (1.4%) and herpes simplex (0.8%). In all cases the side-effects disappeared within a few days. In the third study, the reduction in the diastolic and systolic blood pressures in a group of 1,142 hypertensive psoriatics was evaluated as a function of time. It was demonstrated that while there was no significant age-dependent difference in lowering their diastolic blood pressure throughout the study, differences in lowering systolic measurements between the younger (< 40 y) and older (> 65 y) hypertensive patients were highly significant. On the basis of these studies we conclude that psoriatics aged 65 and over benefit from climatotherapy at the Dead-Sea no less than younger patients, and that, irrespective of age, high blood pressure is not a contraindication for this treatment in psoriatic patients at the Dead-Sea.

Adolescent↗