Showing papers on "Ultraviolet light published in 1977"
TL;DR: The frequencies of occurrence of amber and ochre mutations arising from the G · C → A · T transition have been compared for different mutagens, revealing several striking hotspots.
560 citations
TL;DR: The mutation diminishes UV mutagenesis and UV reactivation of phages λ without affecting the inducibility of phophage λ nor the inhibition of cell division following UV irradiation.
Abstract: Mutants of E. coli defective in susceptibility to UV-induction of mutations were isolated by direct screening for their UV nonmutable phenotype (Umu-). Screening of about 30,000 mutagenized clones of a uvr-B derivative of AB1157 yielded six Umu- strains. The mutants can be classified into three groups by the location of the mutations, umuA, umuB and umuC. Mutations umuA and umuB are, respectively, mapped close to lexA and recA genes and mutations at both loci partially reduce UV mutagenesis. The locus of umuC is between hemA and purB and the mutations at this new locus result in a moderate increase of UV sensitivity. The mutation diminishes UV mutagenesis and UV reactivation of phage lambda without affecting the inducibility of phophage lambda nor the inhibition of cell division following UV irradiation. Related properties of an isogenic strain of a recF- mutant are compared with those of umuC-.
546 citations
TL;DR: Once a remission was induced, there was no difference in its maintenance when patients were treated once a week, once every other week, or once every third week, and each of these schedules was superior to no maintenance treatment.
473 citations
TL;DR: It is suggested that repeated UV irradiation can circumvent an immunologic mechanism that might otherwise destroy nascent UV-induced primary tumors that are strongly antigenic.
Abstract: Chronic irradiation of mice with ultraviolet (UV) light produces a systemic alteration of an immunologic nature. This alteration is detectable in mice long before primary skin cancers induced by UV light begin to appear. The alteration results in the failure of UV-irradiated mice to reject highly antigenic, transplanted UV-induced tumors that are rejected by unirradiated syngeneic recipients. The immunologic aspect of this systemic alteration was demonstrated by transferring lymphoid cells from UV-irradiated mice to lethally x-irradiated recipients. These recipeints were unable to resist a later challenge with a syngeneic UV-induced tumor, whereas those given lymphoid cells from normal donors were resistant to tumor growth. Parabiosis of normal mice with UV-irradiated mice, followed by tumor challenge of both parabionts with a UV-induced tumor, resulted in the growth of the challenge tumors in both UV-irradiated and unirradiated mice. Splenic lymphocytes from tumor-implanted UV-treated mice were not cytotoxic in vitro against UV-induced tumors, whereas under identical conditions cells from tumor-implanted, unirradiated mice were highly cytotoxic. Our findings suggest that repeated UV irradiation can circumvent an immunologic mechanism that might otherwise destroy nascent UV-induced primary tumors that are strongly antigenic.
358 citations
TL;DR: The complete results of the analysis of over 5300 independently derived nonsense mutations in the lacI gene are presented, which have been mapped and divided into specific sites to allow a detailed correlation of the physical and genetic map.
266 citations
TL;DR: These 'equal and opposite' effects represent the second highest enantiomeric enrichments yet reported for an asymmetric photolysis and the first ever reported for a prebiotically important substrate - an amino acid.
Abstract: (RS)-leucine in 0.1 M HCl solution has been subjected to photolysis with 212.8-nm right (R-) and left circularly polarized light (LCPL) obtained from a laser source. RCPL preferentially photolyzed the (R)-leucine component and LCPL the (S)-leucine component of the RS substrate. The enantiomeric excess produced were 1.98% for the 59% conversion with RCPL and 2.50% for the 75% conversion with LCPL. These 'equal and opposite' effects represent the second highest enantiomeric enrichments yet reported for an asymmetric photolysis and the first ever reported for a prebiotically important substrate - an amino acid. Implications regarding the origin of optical activity are briefly discussed.
231 citations
TL;DR: The remarkable susceptibility of SCEs to ultraviolet light or chemicals having similar modes of action, and the simplicity of scoring this event with the aid of the BUdR-labeling method, make SCE a new assay system for hazardous effects of various environmental mutagens and carcinogens.
Abstract: Publisher Summary This chapter discusses the spontaneous and induced sister chromatid exchanges (SCE) as revealed by the 5-bromo-2’-deoxyuridine (BUdR)-labeling method. The elaboration of techniques for labeling chromosomes efficiently in vivo and a comparison of the incidence of SCEs in cells from various tissues or organs of animals, especially immunocompetent cells, germ line cells, and embryonic cells, would provide important clues in determining the existence of spontaneous SCEs and their biological significance which has long remained an enigma. Recently an attempt has been made to explain the evolution of multiple gene families in eukaryotic genomes such as rRNA and immunoglobulin V-gene families in terms of the consecutive occurrence of unequal SCEs. It has been shown that many eukaryotic genomes contain a large (over 70%) DNA fraction in which middle repetitive sequences of about 300 nucleotides are interspersed between single-copy DNA sequences averaging 3000 nucleotides or less in length. A correspondence between the middle repetitive sequences and the sites of meiotic crossing-over has been suggested in liliaceous plants. Strand exchange involving the pairing of these sequences may well have a chance to undergo unequal recombination without affecting the array of structural genes in the chromosome. The remarkable susceptibility of SCEs to ultraviolet light or chemicals having similar modes of action, and the simplicity of scoring this event with the aid of the BUdR-labeling method, make SCE a new assay system for hazardous effects of various environmental mutagens and carcinogens.
211 citations
Journal Article•
TL;DR: Primary tumors from the albino strain were the least antigenic as a group, whereas the C3H- tumors exhibited the greatest degree of antigenicity, which was comparable among the three strains.
Abstract: The carcinogenic effects of chronic exposure to ultraviolet radiation were compared in three inbred mouse strains with different coat colors. Albino mice (BALB/cAnN) developed tumors earlier than agouti [C3H/HeN (mammary tumor virus negative) hereafter called C3H-] or black (C57BL/6N) mice, and a large proportion of the tumors in the albino strain arose on the ears, in contrast to the other strains) in which dorsal tumors predominated. The most common histological types of tumor observed were fibrosarcomas, followed by squamous cell carcinomas. The types and frequency of types were comparable among the three strains. On the basis of a comparison of tumor growth in normal and immunosuppressed syngeneic recipients, primary tumors from the albino strain were the least antigenic as a group, whereas the C3H- tumors exhibited the greatest degree of antigenicity. In BALB/cAnN mice 33% of the ultravioletinduced tumors tested failed to grow in normal syngeneic mice although they grew in immunosuppressed recipients. In C57BL/6N mice 54% and C3H- mice 75% of the tumors tested were not transplantable in normal syngeneic recipients and grew only in immunologically deficient hosts.
210 citations
TL;DR: It is indicated that there are pronounced constraints on 25-hydroxylation of vitamin D, now shown to be equivalent to oral vitamin D in doses of 8000-10 000 I.C.U. daily, which may protect against vitamin-D deficiency in winter.
203 citations
Journal Article•
TL;DR: The defect in postreplication repair previously found in XP variants (excision-proficient XP's) has now been observed in a total of five XP variants and a less severe defect has been found in excision-defective XP's in Complementation Groups A, B, C, and D.
Abstract: Postreplication repair of DNA damage after ultraviolet light irradiation has been examined in a wide variety of human fibroblast strains. The donors were patients with xeroderma pigmentosum (XP) of different complementation groups or other hereditary disorders with indications of radiosensitivity, or with light sensitivity or multiple cancers. The defect in postreplication repair previously found in XP variants (excision-proficient XP's) has now been observed in a total of five XP variants and a less severe defect in postreplication repair has been found in excision-defective XP's in Complementation Groups A, B, C, and D. Complementation Group E and all other cell strains studied showed a response that was not significantly different from that of cells from normal donors. Excision repair was also measured in some of these cell strains and was found to be defective only in XP cells. Ultraviolet cell survival characteristics have been obtained for may of the cell strains. The most sensitive were cells from the excision-deficient XP's and from a sun-sensitive child (11961); the latter had no measurable defect in either excision or postreplication repair. The rest of the survival curves lay in a band limited by normal cell strains on the one hand and the slightly more sensitive excision-proficient XP variant XP30RO. Only in the case of the variants XP30RO and XP7TA were we able to demonstrate any influence of caffeine on cell survival.
199 citations
TL;DR: In both Cockayne fibroblast cultures, the rate of removal of thymidine dimer from the irradiated cellular DNA was normal and this demonstration of a cellular defect in Cockayne cells suggests that there may be an enzymatic defect in the repair of UV light-induced damage.
Abstract: Two unrelated children, a boy 2 1/2 years old and a girl 4 years old, were affected with the cachectic dwarfism of Cockayne syndrome. Fibroblast cultures derived from these patients exhibited increased sensitivity to ultraviolet (UV) light, but not to x-irradiation, as measured by colony-forming ability. In both Cockayne fibroblast cultures, the rate of removal of thymidine dimer from the irradiated cellular DNA was normal. This demonstration of a cellular defect in Cockayne cells suggests that there may be an enzymatic defect in the repair of UV light-induced damage.
TL;DR: It is reported here that BS fibroblasts are abnormally sensitive to ultraviolet irradiation in vitro and show a rate of DNA synthesis and DNA chain maturation lower than controls, and do not have defective bypass of ultraviolet light-induced lesions during DNA replication as xeroderma pigmentosum (XP) variants.
Abstract: BLOOM'S syndrome (BS) is a rare, autosomal recessive condition of pre-natal and post-natal growth retardation, sun-induced telangiectatic erythema, impaired immunological function and predisposition to cancer1,2. BS cells show a high incidence of chromosome breakage and rearrangement often with abnormal nuclear morphology. Chromosome exchanges appear mainly to involve homologous chromosomes, while sister chromatid exchanges are abnormally frequent3. These features suggest a defect of DNA replication or repair. In particular, the high incidence of sister chromatid exchanges may be explained if free ends in the DNA, resulting from abnormalities of DNA synthesis and/or repair, act as initiation points for exchange4. We report here that BS fibroblasts are abnormally sensitive to ultraviolet irradiation in vitro and show a rate of DNA synthesis and DNA chain maturation lower than controls. They do not, however, have defective bypass of ultraviolet light-induced lesions during DNA replication as xeroderma pigmentosum (XP) variants5.
TL;DR: The substrate specificity of the enzyme was in agreement with its proposed function in flavonoid biosynthesis, and the two cosubstrates, ATP and CoA, exhibited sigmoidal saturation kinetics, which were interpreted as indicating homotropic, allo-steric effects.
TL;DR: In this paper, the authors found that platelet aggregation occurs only in the illuminated field and adhere to arteriolar and venular walls, but only when sodium fluorescein is first injected intravascularly to provide a light absorbing, heat generating target.
Abstract: After a certain period of time filtered ultraviolet light produces platelet aggregation in microvessels on the cerebral surface of the mouse, but only when sodium fluorescein is first injected intravascularly to provide a light-absorbing, heat-generating target. The platelet aggregates fluoresce. They occur only in the illuminated field and adhere to arteriolar and venular walls. Vasoconstriction is not detected prior to or up to 30 seconds after aggregation. Electron microscopy reveals damaged endothelium and undamaged red cells, as well as aggregates consisting almost exclusively of platelets in varying stages of aggregation, pseudopod formation, and degranulation. The time between onset of the noxious stimulus and recognition of the first aggregate can be measured as the vessels are observed microscopically. This "time of aggregation" is prolonged by pentobarbital as opposed to urethane anesthesia, and also is related to time elapsed after craniotomy. We also found that aspirin and indomethacin significantly prolong time to first aggregate, but only on the arteriolar side of the circulation. This is so even though the composition of the aggregates is the same on both the arteriolar and venular sides. Heparin has no effect.
TL;DR: Ultraviolet phototherapy is a safe, convenient, inexpensive and effective treatment for uremic pruritus and was unaffected by the presence of secondary hyperparathyroidism.
Abstract: We studied the effect of ultraviolet-light phototherapy on severe persistent pruritus in 18 adult patients on hemodialysis. Patients were randomly assigned to one of two light sources. The experimental group received conventional sunburn-spectrum light in gradually increasing doses. The control group received time-matched exposures to longwave ultraviolet light. All patients received eight exposures to the entire skin surface over a four-week treatment period. Nine of 10 patients in the sunburn-spectrum group reported marked decrease in pruritus as opposed to two of eight in the placebo group (P<0.01). Of those responding to sunburn-spectrum light, improvement usually occurred two to three weeks into treatment. Mild sunburn, noted by some patients in this group, was the only side effect. The response to phototherapy was unaffected by the presence of secondary hyperparathyroidism. Ultraviolet phototherapy is a safe, convenient, inexpensive and effective treatment for uremic pruritus. (N Engl J Med...
TL;DR: Four entomopathogenic viruses and one each of an entomopathic bacterium, fungus, and protozoan were inactivated when exposed to ultraviolet light; the half-life was less than 4 h in every instance.
Abstract: Four entomopathogenic viruses and one each of an entomopathogenic bacterium, fungus, and protozoan were inactivated when exposed to ultraviolet light; the half-life was less than 4 h in every instance. Relative ranking in stability of the entomopathogens was as follows: B. thuringiensis Berliner > Nomuraea rileyi (Farlow) Samson > entomopox Virus > nucleopolyhedrosis virus = cytoplasmic polyhedrosis virus > Vairimorpha (= Nosema ) necatrix (Kramer) > granulosis virus.
TL;DR: An endonuclease which is active upon DNA exposed to ultraviolet light at a photoproduct other than thymine dimers has been extensively purified from Escherichia coli.
TL;DR: It follows that monomeric thymine ring saturation represents a minor photochemical reaction relative to pyrimidine dimerization in the far-ultraviolet but a major reaction in the near-ult ultraviolet.
Abstract: The formation of products of the 5,6-dihydroxydihydrothymine-type (t/sup UV/) and cyclobutane-type pyrimidine photodimers (TT) and tritiated water (/sup 3/H/sub 2/O) by monochromatic light at 240, 265, 280, and 313 nm (6-nm half-band-width) was investigated in HeLa S-3 cells which were labeled in their DNA with (methyl-/sup 3/H)thymine. The efficiency of the formation of all three products was maximal at 280 nm and dropped towards longer and shorter wavelengths. The efficiency of TT formation dropped more strongly towards longer and shorter wavelengths than the efficiency of t/sup UV/ formation (comparison at a dose of 5 x 10/sup 3/ J m/sup -2/). Total monomeric thymine ring saturation (t/sub sat/) was estimated from the t/sup UV/ data. It was calculated that 0.06 t/sub sat/ was formed for each TT at 280 nm, but 0.73 t/sub sat/ per TT at 313 nm. It follows that monomeric thymine ring saturation represents a minor photochemical reaction relative to pyrimidine dimerization in the far-ultraviolet but a major reaction in the near-ultraviolet. The formation of /sup 3/H/sub 2/O by ultraviolet light from (methyl-/sup 3/H) thymidine-labeled HeLa cells most likely indicates the attack of hydroxyl radicals on the cellular DNA; 5-methyleneuracil radicals formed as a consequence of the reaction more » may be important intermediates in ultraviolet-induced DNA-DNA and DNA-protein cross-linking. « less
TL;DR: A small endodeoxyribonuclease that is active on single-stranded DNA has been extensively purified from Escherichia coli so as to be free of other known DNases, and the enzyme specificity suggests that it might act at abnormal regions in DNA, so that its in vivo function could be to initiate an excision repair sequence.
TL;DR: Inducible error-prone repair in E. coli is manifested by an increased capacity for DNA synthesis on damaged φX174 DNA, which is also an inhibitor of this particular inducible DNA synthesis.
TL;DR: Bean golden yellow mosaic virus (GYMV) DNA sedimented in sucrose density gradients and in an analytical ultracentrifuge as a single component and represents the first reported single-stranded DNA virus from plants.
TL;DR: It is suggested that short-term UV irradiation of mice leads to an increase in suppressor cell activity, thereby causing an inhibition in the host's ability to respond to an antigenic UV-induced tumor.
Abstract: When normal mice are exposed for short periods to ultraviolet light (uv), they support the progressive growth of transplanted syngeneic uv-induced tumors. Normal nonirradiated mice almost always reject these tumor implants. The uv-mediated suppression of the antitumor response can be adoptively transferred to normal syngeneic mice with lymphoid cells derived from short-term uv-irradiated donors. Transfer of the suppressive effect is dosage dependent and also appears to require the presence of viable T lymphocytes. Suppressive activity was observed in both the spleen and thymus of uv-irradiated donors. In the preceding paper we have established that uv irradiation does not cause a general depression of testable immune functions. Collectively these data suggest that short-term uv irradiation of mice leads to an increase in suppressor cell activity, thereby causing an inhibition in the host's ability to respond to an antigenic uv-induced tumor. The possible role of this phenomenon in the mechanism of uv carcinogenesis is discussed.
Journal Article•
TL;DR: Age distribution of the cancer-bearing patients and their DNA repair characteristics suggest that almost all xeroderma pigmentosum patients will develop skin cancers unless their cells have nearly normal levels of DNA repair.
Abstract: Summary Fifty xeroderma pigmentosum patients in Japan were examined for clinical characteristics and DNA repair of their cells. Skin cancers developed in 22 patients. Most of the patients without skin cancers were children, except for 5 older patients who had intermediate or nearly normal levels of DNA repair in their cells. All patients younger than 10 years old had no or very low activity of unscheduled DNA synthesis after ultraviolet light irradiation. Three genetic complementation groups, A, D, and E, and variants were found. Many Group A patients and no Group C patients characterized Japanese patients, compared with those in Europe and the United States, where Group C patients were most frequent. The high frequency of patients with low DNA repair capacities in their cells may account for the apparent high frequency of xeroderma pigmentosum patients in Japan. Age distribution of the cancer-bearing patients and their DNA repair characteristics suggest that almost all xeroderma pigmentosum patients will develop skin cancers unless their cells have nearly normal levels of DNA repair.
TL;DR: The response of the excision-repair deficient cells suggest that unrepaired damage, produced by UVR is involved in the production of SCE, which is significantly higher than in UV-exposed control cells.
Abstract: The role of DNA repair mechanisms in the induction of sister chromatid exchanges (SCE) after exposure to ultraviolet radiation was investigated in xeroderma pigmentosum cells. Cells from different excision-deficient XP strains, representing the 5 complementation groups in XP, A, B, C, D and E, and from excision-proficient XP variant strains were irradiated with low doses of UVR (0–3.5 J/m 2 ). The number of SCE was counted after two cycles in the presence of BUdR. In cells of the complementation groups A, B, C and D the number of SCE was significantly higher than in UV-exposed control cells. The frequencies of SCE in group E cells and in XP variant cells were not different from those in control cells. Treatment with caffeine (0–200 μg/ml) did not result in a different response of variant cells compared with normal cells. A simple correlation between SCE frequency and residual excision-repair activity was not observed. The response of the excision-repair deficient cells suggests that unrepaired damage, produced by UVR is involved in the production of SCE.
TL;DR: It was concluded that trixosalen binds at the sites corresponding to the regular nuclease-sensitive regions of the chromatin in nuclei, which are characteristic of native, untreated nuclei are digestion.
Abstract: Derivatives of the furocoumarin, psoralen, can penetrate intact cells or nuclei and cross-link opposite strands of the chromosomal DNA under the influence of long wave- length ultraviolet light. The potential of trioxsalen (4,5',8- trimethylpsoralen) as a probe for chromatin structure has been investigated. The DNA in both embryo nuclei and tissue cul- ture cells from Drosophila meianogaster was found to be about 90% protected from trioxsalen binding relative to purified DNA. Digestion of trioxsalen-treated nuclei by micrococcal nuclease and gel electrophoresis of the resulting DNA gave the
TL;DR: The mutagenic activities of the positive control mutagens ultraviolet light, potassium chromate, ethyl methanesulphonate and benzo(a)pyrene were detected in the experiments, however, no Mutagenic activity was found to be associted with any of the asbestos and glass fibres tested over a wide range of concentrations.
Abstract: Asbestos fibres are carcinogenic in man and experimental animals but fine glass fibres are known, at present, only to be carcinogenic in experimental animals. Asbestos and glass fibres have been studied in mutation tests using auxotrophic strains of Escherichia coli and Salmonella typhimurium . The mutagenic activities of the positive control mutagens ultraviolet light, potassium chromate, ethyl methanesulphonate and benzo(a)pyrene were detected in the experiments. However, no mutagenic activity was found to be associated with any of the asbestos and glass fibres tested over a wide range of concentrations. The implications of these findings for the mode of action of asbestos and glass fibres as carcinogens are discussed.
TL;DR: It is suggested that lipid peroxides or their degradation products, whether introduced exogenously or derived from the peroxidation of endogenous phospholipids in semen, constitute a potential hazard to the functional integrity of spermatozoa.
Abstract: The toxicity of exogenous fatty acid peroxides toward spermatozoa was investigated. Washed ram spermatozoa with vigorous motility were mixed with an equal volume of an emulsion of heavily peroxidized arachidonic acid. Spermatozoa became immotile instantly. Low peroxidized emulsions had little effect. Saturated fatty acids were also tested in this manner but failed to immobilize spermatozoa either before or after exposure to ultraviolet light. Unsaturated fatty acids even when supposedly free from peroxides gave a positive peroxide test and inhibited the motility of spermatozoa. Microscopic examination of spermatozoa showed numerous tiny droplets adhering to the surface and plasma membranes extensively damaged. In the presence of arachidonic acid in toxic doses oxygen uptake is reduced and fructolysis abolished. The action of arachidonic acid could be moderated by prior treatment of the spermatozoa with dialized egg yolk or milk. Tocopherol albumin and mercaptoethanol were ineffective protectors. Attempts to restore motility and metabolism by washing the inactivated spermatozoa with dialyzed egg yolk failed and the addition of fructose lactate or ATP were also without effect.
TL;DR: The findings of this study clearly show that when this pit and fissure sealant is retained, its is effective in preventing caries in sealed tooth surfaces.
Abstract: This report contains findings on retention and caries prevention observed five years after a BIS-GMA pit and fissure sealant polymerized by ultraviolet light was applied to occlusal surfaces of posterior teeth of children in a community with negligible concentrations of fluoride in its water supply. Single applications of an adhesive sealant were made to the teeth of children in kindergarten, first grade, and seventh grade. Five years later, 42% of the sites initially sealed retained all the sealant. Also, 93% of the sites from which sealant was only partly lost were free of caries. Findings show that when the sealant is partly or totally retained, it is effective in preventing caries.
Journal Article•
TL;DR: The results are consistent with a "two-stage" hypothesis of carcinogenesis which includes mutational and epigenetic mechanisms to explain the initiation and promotion phases and do not support the hypothesis that the tumor-promoting activity of TPA is due to its ability to inhibit "error-free" excision repair.
Abstract: 12-0-Tetradecanoyl-phorbol-13-acetate (TPA) and phorbol were tested in Chinese hamster cells for their effects on mutagenesis (resistance to 6-thioguanine and to ouabain), DNA repair, and survival after ultraviolet (UV) irradiation. Recovery of 6-thioguanine- and ouabain-resistant colonies was significantly increased by TPA treatment and, to a lesser extent, by phorbol in UV-irradiated cells. Moreover, maximum enhancement of recoverable UV-induced 6-thioguanine- and ouabain-resistant mutants occurred when TPA was present after the mutation "expression" time and after the completion of DNA repair. This eenhancement effect, while persisting up to 18 days in the 6-thioguanine mutation system, was maximal when TPA was applied about 2 days after UV irradiation for the ouabain resistance mutation system. No significant decrease in cell survival was noted after post-UV treatment with TPA or phorbol, under conditions where there was a slight but nonspecific inhibition of unscheduled DNA repair synthesis. These results do not support the hypothesis that the tumor-promoting activity of TPA is due to its ability to inhibit "error-free" excision repair. The results are, however, consistent with a "two-stage" hypothesis of carcinogenesis which includes mutational and epigenetic mechanisms to explain the initiation and promotion phases.
TL;DR: Methoxsalen followed two hours later by ultraviolet light (UVA) resulted in clinical clearing of skin lesions in seven patients with plaque stage MF and one patient with erythrodermic MF, and Histopathologic clearing of mycosis fungoides was demonstrated with the clinical clearing.
Abstract: • Twelve cases of cutaneous mycosis fungoides (MF) with erythroderma, plaques, and tumors were treated with photochemotherapy. Methoxsalen followed two hours later by ultraviolet light (UVA) resulted in clinical clearing of skin lesions in seven patients with plaque stage MF and one patient with erythrodermic MF. Four patients with both plaque and tumor stage MF showed clearing of plaques but not the tumors. Phototherapy units consisted of boxes with 16 to 64 UVA lights. The mean number of treatments to clear was 17.4. The mean total dose to clear was 134.8 joules. The mean dose of maintenance UVA was 5.6 joules/sq cm. Histopathologic clearing of mycosis fungoides was demonstrated with the clinical clearing. (Arch Dermatol113:1047-1051, 1977)