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Biomedical subjects

W Frain-Bell

Publications and source records attributed to W Frain-Bell.

At least 37 records · Page 2Linked to original sources
PubMed1977

Photochemotherapy in the treatment of psoriasis.

This article describes the satisfactory clinical improvement obtained in the majority of a group of 72 patients with psoriasis of various types as a result of the oral and/or topical administration of 8-methoxypsoralen followed by long wavelength ultraviolet irradiation. The irradiation source used was that of conventional longwave UV fluorescent tubes mounted in a specially constructed cubicle. Until such time as the long term effect of this form of photochemotherapy on the cell has been evaluated and the most appropriate regime worked out, it would seem to be important to restrict the amount of irradiation used to that required to produce acceptable maintained clinical improvement.

Adolescent↗
PubMed1977

A study of oil of bergamot and its importance as a phototoxic agent. I. Characterization and quantification of the photoactive component.

It is important in the technique of photopatch testing, using oil of bergamot, to have determined the concentration of the active psoralen, bergapten, so as to avoid false negative responses in the assessment of phototoxic reactions. Techniques for assessing the phototoxic components of oil of bergamot are described and quantitative analyses of bergapten, the only significant photoactive compound in the samples examined, are reported. The phototoxicity of bergapten was found to be nearly the same as that of xanthotoxin (8-MOP) in tests on human skin.

Coumarins↗
PubMed1977

Sister chromatid exchanges in lymphocytes of psoriatics after treatment with 8-methoxypsoralen and long wave ultraviolet radiation.

Sister chromatid exchange rates in cultured cells from the blood of patients receiving photochemotherapy have been examined as an indicator of possible genetic hazards of the treatment to patients with psoriasis. Lymphocytes of untreated patients with psoriasis appear to have sister chromatid exchange rates after 72 h of culture indistinguishable from normal subjects and there is no evidence from these studies that sister chromatid exchanges are significantly increased in the lymphocytes of patients receiving photochemotherapy. Cells from blood taken from patients who had been given 8-methoxypsoralen orally 2 h before and then irradiated with UV-A in vitro were found to have an increased exchange rate which could be related to the presence of the drug in the peripheral circulation.

Chromatids↗
PubMed1977

The treatment of erythropoietic protoporphyria. Experience with beta-carotene.

In a group of 19 subjects suffering from erythropoietic protoporphyria the administration of beta-carotene appeared to produce improvement based on a subjective assessment of alterations in exposure times required to produce the symptoms and signs of the condition. This clinical improvement however failed to show a direct correlation with the prophyrin levels in blood and faeces, or with the estimation by phototesting of the minimal response dose within the action spectrum of 400-600 nm.

Adolescent↗
PubMed1977

A study of oil of bergamot and its importance as a phototoxic agent. II. Factors which affect the phototoxic reaction induced by bergamot oil and psoralen derivatives.

Using a standardized open photopatch test technique, the phototoxic reactions produced by bergamot oil bergapten (5-methoxypsoralen) the active component of the oil, and xanthotoxin (8-methoxypsoralen) were studied. The reaction was affected by a range of factors such as the vehicle (PMF or ethanol), the concentration of ethanol in the vehicle, the skin site, the interval between application of the psoralen and irradiation, the hydration of the skin, and the degree of natural or sun-induced pigmentation. Repeated photopatch testing at the same skin site produced an increase in sensitivity. Eye colour, natural susceptibility to suntanning, age, and sex, had no effect on the phototoxic response to psoralens.

Adolescent↗
PubMed1976

The investigation of quindoxin photosensitivity.

Quindoxin (quinoxaline di-N-oxide) is a photosensitizer capable of producing photocontact dermatitis. The study of a group of seven affected subjects has provided evidence of persistent light reaction and "photoallergy", most probably to the parent substance and not to any photoproduct or contaminant. Clinical and photobiological similarities to the photosensitivity dermatitis and actinic reticuloid syndrome were demonstrated.

Administration, Topical↗
PubMed1975

A study of physical light screening agents.

In those photodermatoses in which the action spectrum involves wavelengths outside the short ultraviolet (i.e. is greater than 320 nm) little protection can be obtained against long UV (is greater than 320 nm) by the application of chemical light screening agents. An action spectrum involving wavelengths is greater than 320 nm is a common occurrence and may necessitate the additional provision of protection from a physical light screening agent. Such a physical agent is titanium dioxide and in a study of its use in a variety of formulations using in vitro techniques it was shown to be effective throughout the wavelengths 400-700 nm. It was also shown to have a satisfactory protective capacity in those photodermatoses in which the action spectrum involves wavelength peaks 365 nm (335-395 nm) and 400 nm (370-430 nm). It also has a reasonable cosmetic acceptability provided care is taken to incorporate in the formulations colouring agents which can be varied to suit the individual patient.

Cosmetics↗
PubMed1975

A study of chemical light screening agents.

In a group of 104 non-photosensitive subjects and seventy-eight suffering from a variety of photodermatoses, the most effective protective preparation against irradiation by short UV sunburn wavelengths (smaller than 320 nm) was found to be a mixture of 5% para-aminobenzoic acid and 2.5% of the ester amyl dimethylaminobenzoate in 70% ethanol with para-aminobenzoic acid being usually more effective than the ester, and mexenone the least effective individually. The protective capacity was found to be reduced by showering but not by exercise. The addition of glycerol to the formulations did not affect their protective capacity although the addition of propylene glycol did increase the protection obtained.

Aminobenzoates↗