HIV-positive patients differ from HIV-negative patients in indications for and type of UV therapy used

BACKGROUND

Treatments using UV, UVB, or oral psoralen and UVA (PUVA) have been advocated for the care of HIV-infected persons with skin diseases. Concerns about the safety of these treatments exist.

OBJECTIVE

We attempted to determine the characteristics of HIV infected persons receiving UV therapy and establish the reasons for and type of treatment administered.

METHODS

During two 2-week periods, we prospectively ascertained basic information on all patients treated at 40 phototherapy clinics and detailed clinical information on patients known to be infected with HIV.

RESULTS

We identified 3716 persons receiving UV therapy, including 311 known to be infected with HIV. When compared with patients not known to be infected with HIV, HIV-positive patients were significantly more likely to be treated with UVB rather than PUVA and were more likely to be treated for pruritic conditions rather than psoriasis.

CONCLUSION

There were great variations in the relative reliance on UVB and PUVA among centers. There appears to be no agreement as to which type of UV therapy is optimal for patients infected with HIV. Most patients known to the treating clinician to be HIV positive are in the advanced stages of HIV disease. The number of persons with less advanced HIV disease receiving treatment remains unquantified but may be even more clinically important.

Mandibular molars with five canals: report of two cases

A mandibular first and second molar found to contain five root canals are described. Recent literature pertaining to unusual root canal morphological structure is reviewed and a recommendation is made for a complete and thorough examination of the chamber floor for even seemingly straightforward and simple nonsurgical endodontic cases.

UV-induced mutagenesis at the hypoxanthine-guanine phosphoribosyl transferase locus in two L5178Y mouse lymphoma cell strains with different UV sensitivities

Two strains of L5178Y mouse lymphoma cells, L5178Y-R (LY-R) and L5178Y-S (LY-S), differ markedly in their sensitivity to 254 nm UV radiation (D0 = 0.7 and 5.5 J/m2; n = 6.0 and 2.0 for LY-R and LY-S cells, respectively). In this study, the frequency of hypoxanthine-guanine-phosphoribosyl-transferase-deficient mutants was determined, using 6-thioguanine (TG) as a selective agent, in populations of LY-R and LY-S cells exposed to various fluences of UV radiation. The spontaneous mutation frequency for LY-R cells was (3.7 +/- 0.6) X 10(-5) TGr mutants per viable cell, and the UV induction rate was (2.2 +/- 0.8) X 10(-4) TGr mutants per viable cell, per J/m2. Both spontaneous and induced mutation frequencies were much lower for LY-S cells. The spontaneous mutation frequency for these cells were too low to make its measurement practicable (less than 0.0013 X 10(-5) TGr mutants per viable cell). Mutation induction rate was (4.2 +/- 2.2) X 10(-7) TGr mutants per viable cell, per J/m2. These differences in mutability do not appear to be due to gene duplication in LY-S cells, or to selective growth disadvantage of LY-S-derived TG-resistant mutants. Possible mechanisms underlying the differences in mutability of LY-R and LY-S cells are considered.

A Comparison of Soybean Agglutinin in Cultivars Resistant and Susceptible to Phytophthora megasperma var. sojae (Race 1)

The amount of soybean agglutinin (SBA) detectable by radioimmunoassay in seeds of resistant cultivars to Phytophthora megasperma var. sojae was approximately twice that of susceptible cultivars. SBA was preferentially released at earlier times (6-9 hours) and in higher amounts in the imbibate from resistant cultivars as compared to susceptible cultivars. The lectin in the imbibate was immunologically identical to the seed lectin, indicating little or no proteolysis had occurred, and was active in hemagglutination. Binding of fluorescein isothiocyanate-labeled SBA to mycelial cell walls could be abolished by adding N-acetyl galactosamine or galactose. Purified SBA at concentrations of 150 to 300 micrograms inhibited mycelial growth by 50%, and the imbibate from Govan (resistant) cultivar was more inhibitory than the imbibate from Shore (susceptible) cultivar. Removal of SBA from the imbibate by affinity chromatography abolished the inhibition of mycelial growth, but the inhibition could be recovered from the eluant containing lectin.

Ultraviolet light action spectra for neoplastic transformation and lethality of Syrian hamster embryo cells correlate with spectrum for pyrimidine dimer formation in cellular DNA

Action spectra were determined for neoplastic transformation, production of pyrimidine dimers, and lethality in Syrian hamster embryo cells. Of wavelengths between 240 and 313 nm, the most effective were 265 and 270. The relative sensitivities per quantum for transformation, pyrimidine dimer production, and lethality were essentially the same at each of the wavelengths tested. This action spectrum for transformation, which is relevant to carcinogenesis, is similar to spectra obtained previously by measuring other cellular responses in either microbial or mammalian systems. Because the action spectra for cytotoxicity and transformation are the same as the spectrum for dimer production, DNA is suggested as the target for all these processes.

Sunlight-induced mutagenesis and toxicity in L5178Y mouse cells: determination and comparison with other light sources

Compared to the basis of equal exposure, in joules per square meter (J/m2) the mutagenic and toxic effects in L5178Y mouse lymphoma cells of radiation emitted by some fluorescent lamps and a sunlamp are quantitatively similar to solar radiation effects at the earth's surface. When the relative intensities of radiation are taken into account, the artificial light sources range from 8 to 1/222 times as mutagenic and 4.1 to less than 1/99 times as toxic as sunlight.

Mutagenic effect on L5178Y mouse lymphoma cells by growth in ethylene oxide-sterilized polycarbonate flasks

The mutation frequency of L5178Y mouse lymphoma cells to resistance to 5'-bromo-2'-deoxyuridine increased 6- to 14-fold after growth in ethylene oxide-sterilized polycarbonate culture flasks compared to growth in glass flasks. No comparable increase was observed when L5178Y cells were grown in identical polycarbonate culture flasks sterilized by autoclaving.

Toxicity and mutagenicity of radiation from fluorescent lamps and a sunlamp in L5178y mouse lymphoma cells

Unfiltered broad spectrum radiation emitted by black light, cool white, and black light blue fluorescent lamps and a sunlamp, is both toxic and mutagenic to L5178Y mouse lymphoma cells when the cells are irradiated in phosphate-buffered saline. The increase in mutant frequency seen after exposure of the cells is linear throughout the range of exposures tested. The linear increase in mutagenesis is observed even at exposure levels which do not cause significant toxicity. To facilitate comparison of the differing rates of mutagenesis derived from exposure-response curves obtained for each light source, we have defined a parameter, joule-equivalent mutagenesis (jem), equal to mutants per 10(5) survivors per joule per square meter. Jem values are calculated using the integrated irradiance of each lamp. Based on jem values, the relative mutagenicity of the various lamps tested (compared with a germicidal ultraviolet lamp) is 3 x 10(-3) for the sunlamp, 1 x 10(-4) for the black light and cool white lamps, and 3 x 10(-5) for the black light blue lamp. The toxic and mutagenic effects of the lamps are in reasonable agreement with their relative spectral output from 290 to 330 nm.

Synthesis of desthiobiotin from 7,8-diaminopelargonic acid in biotin auxotrophs of Escherichia coli K-12

The synthesis of desthiobiotin from 7,8-diaminopelargonic acid (DAP) was demonstrated in resting cell suspensions of Escherichia coli K-12 bioA mutants under conditions in which the biotin locus was derepressed. The biosynthetically formed desthiobiotin was identified by chromatography, electrophoresis, and by its ability to support the growth of yeast and those E. coli biotin auxotrophs that are blocked earlier in the biotin pathway. Optimal conditions for desthiobiotin synthesis were determined. Desthiobiotin synthetase activity was repressed 67% when partially derepressed resting cells were incubated in the presence of 3 ng of biotin per ml. Serine, bicarbonate, and glucose stimulated desthiobiotin synthesis apparently by acting as sources of CO(2). The results of this study are consistent with an earlier postulated pathway for biotin biosynthesis in E. coli: pimelic acid --> 7-oxo-8-aminopelargonic acid --> DAP --> desthiobiotin --> biotin.