Showing papers on "Ultraviolet light published in 1976"

The production of resveratrol by Vitis vinifera and other members of the Vitaceae as a response to infection or injury

Abstract: Trans -resveratrol (4,3′,5′-trihydroxy stilbene) has been identified as the major component responsible for the blue fluorescence of grapevine leaf tissue following fungal infection or exposure to ultraviolet light. The biosynthesis of this compound appears to be a non-specific response of members of the Vitaceae to infection or injury. The compound is not detectable in healthy leaves but accumulates to between 50 and 400 μg/g fresh weight in infected or u.v.-irradiated leaves and is a major constituent ( c. 700 μg/g) of lignified stem tissue. The biological significance of the production of resveratrol is discussed.

Frequency of ultraviolet light-induced mutations is higher in xeroderma pigmentosum variant cells than in normal human cells

Abstract: PATIENTS with the inherited disease, xeroderma pigmentosum (XP), are subject to multiple carcinomas of the skin on areas exposed to sunlight1. Fibroblasts from the skin of the majority of these patients (classical XP) have been shown to be deficient in excision repair of lesions induced in DNA by ultraviolet radiation1–3. One group of patients, however, has been designated ‘XP variants’ because, although they suffer the clinical manifestations of the disease, they carry on normal excision repair of such ultraviolet-light damage to DNA4–6. Lehmann et al.6 reported that cells from such XP variants are abnormally slow in converting initially low molecular weight DNA, synthesised after ultraviolet irradiation, into high molecular weight DNA similar in size to that produced in unirradiated cells. Although these authors suggest that such abnormal DNA replication might explain why such patients are susceptible to cancer of the skin, they do not propose any mechanism. If the somatic cell mutation hypothesis on the origin of cancer, first suggested by Boveri7, is correct one would expect the frequency of mutations induced by ultraviolet light to be higher in cells derived from skin biopsies from both classical and variant XP patients than in cells from normal persons. To test this hypothesis, we have carried out a series of quantitative investigations comparing the frequency of ultraviolet-light induced mutations to azaguanine resistance in normal human skin fibroblasts with that found in various strains derived from classical and variant XPs. We have found that cells derived from both kinds of XP patients indeed show much higher frequencies than normal cells. The data comparing two classical XP strains with normal cells have been published8,9. Here, we present data obtained with variant strain, XP4BE.

Oral methoxsalen photochemotherapy of mycosis fungoides

Abstract: The cutaneous manifestations of mycosis fungoides have been successfully treated in nine patients for 16 to 28 months with oral methoxsalen and subsequent irradiation with longwave ultraviolet light. The efficacy of this therapy was confirmed in one patient, who showed complete clearing of generalized plaques after 1 month (12 treatments) except for a shielded control area which worsened during this period. Methoxsalen photochemotherapy may prove a valuable addition to therapies currently available for mycosis fungoides and may obviate some of the problems associated with conventional management of this disorder.

Photochemotherapy for Psoriasis With Orally Administered Methoxsalen

Abstract: • Photochemotherapy denotes a therapeutic approach that is based on the interaction of light and a photoactive drug. This study describes the efficacy of photochemotherapy, using orally administered methoxsalen and long-wave ultraviolet light in 91 patients with severe, generalized psoriasis. Oral administration of methoxsalen was followed by exposure to a high-intensity long-wave ultraviolet light source, emitting a continuous spectrum between 320 and 390 nm (peak, 365 nm) and an energy of 5.6 to 7.5 mw/sq cm at 15 cm. There was complete clearing of 82 patients (90%), a 90% to 100% clearing in seven (8%), and a satisfactory improvement in two (2%). A paired comparison study in 54 patients showed photochemotherapy to be far more effective than ultraviolet light emitted by fluorescent bulbs or a xenon source. Eighty-five percent of the patients receiving outpatient maintenance treatment have remained in remission for periods up to 400 days. ( Arch Dermatol 112:943-950, 1976)

Coordinated induction and subsequent activity changes of two groups of metabolically interrelated enzymes. Light-induced synthesis of flavonoid glycosides in cell suspension cultures of Petroselinum hortense.

Abstract: The enzymes of the flavonoid glycoside pathway were specifically induced upon irradiation of a 10-day-old, dark-grown cell suspension culture of Petroselinum hortense Hoffm, with ultraviolet light. The curves for the activity changes of a first sequence of three enzymes (group I) revealed only small, but significant, differences. Sharp peaks in these enzyme activities were observed at about 17. 22, and 23 h after the onset of the irradiation. The apparent half-lives during the subsequent periods of decline ranged, in the same order, from about 10 to 15 and 17 h. No significant differences were found for the lag periods preceding the increases in the three enzyme activities. The possibility is discussed that the slight differences in the patterns of the light-induced activity changes are mainly due to different rates of degradation of the enzymes, suggesting an otherwise largely interpendent regulation. The patterns of the activity changes of four enzymes of the second sequence (group II) differed greatly from those observed for group I, but were again similar to one another. Thus, the two groups of enzymes appear to be regulated differently, despite their concomitant induction. A sigmoidal curve for the accumulation of the flavonoid glycosides was obtained upon the induction of the enzymes. This curve corresponded closely to that derived by integration of the curve for the activity changes of the first enzyme of group I. phenylalanine ammonia-lyase. It is concluded that this enzyme might be rate-limiting for the entire pathway.

Detection and repair of single-strand breaks in nuclear DNA

Abstract: DIRECTLY or indirectly phosphodiester bonds in DNA are broken when living cells are irradiated by ionising radiations or ultraviolet light. There are various sophisticated techniques for monitoring radiation damage1–6. We describe here how radiation damage in DNA and its repair can be detected simply in the white cells of human blood. The method is very sensitive and should prove useful in screening populations for abnormal repair mechanisms. As there is also great interest in methods for detecting environmental agents that damage DNA2,7, we have applied the method to detect the damage caused by mitomycin C.

DNA single-strand breaks during repair of UV damage in human fibroblasts and abnormalities of repair in xeroderma pigmentosum.

Abstract: The method of DNA alkaline elution was applied to a study of the formation and resealing of DNA single-strand breaks after irradiation of human fibroblasts with ultraviolet light (UV). The general features of the results were consistent with current concepts of DNA excision repair, in that breaks appeared rapidly after UV, and resealed slowly in normal fibroblasts, whereas breaks did not appear in those cells of patients with xeroderma pigmentosum (XP) that are known to have defects in DNA repair synthesis. The appearance of breaks required a short post-UV incubation, consistent with the expected action of an endonuclease. Cells of the variant form of XP characterized by normal DNA repair synthesis exhibited normal production of breaks after UV, but were slower than normal cells in resealing these breaks. This difference was enhanced by caffeine. A model is proposed to relate this finding with a previously described defect in post-replication repair in these XP variant cells. DNA crosslinking appears to cause an underestimate in the measurement of DNA breakage after UV.

Photochemotherapy of vitiligo. Use of orally administered psoralens and a high-intensity long-wave ultraviolet light system.

Abstract: • A new light source that provides highintensity ultraviolet light (UVA) (300 to 400 nm) to the entire body surface makes orally administered psoralen treatment of vitiligo with an artificial light practical. In the 26 patients studied, the degree of repigmentation with either trioxsalen (TMP) or methoxsalen (8-MOP) and high intensity UVA was at least as great as that with the same oral agents and sunlight. With artificial UVA and similar treatment conditions, the two psoralen derivatives were compared in the treatment of vitiligo; TMP stimulated repigmentation as well as 8-MOP and caused fewer side effects. (Arch Dermatol112:1531-1534, 1976)

Ultraviolet Susceptibility of BCG and Virulent Tubercle Bacilli

Abstract: To test the effectiveness of irradiating the upper air of a room with ultraviolet light at reducing the concentration of airborne tubercle bacilli, the susceptibility to the germicidal effects of ultraviolet light, Z, was determined for various mycobacteria. Virulent tubercle bacilli and bacille Calmette-Guerin (BCG) were equally susceptible to ultraviolet radiation, whereas Mycobacterium phlei had 10 times their resistance (Z, approximately one-tenth that for M. tuberculosis). The effectiveness against BCG of upper air ultraviolet irradiation in a room was tested directly by nebulizing BCG into the air of the room and monitoring its rate of disappearance. With one 17-watt fixture operating, the rate of disappearance increased 6-fold; with 2 fixtures operating (46 watts total), the rate of disappearance increased 9-fold. This implies that under steady-state conditions, the concentrations of airborne organisms with ultraviolet light(s) on would have been one-sixth and one-ninth, respectively. The increase ...

Ultraviolet light protection, enhancement of ultraviolet light mutagenesis, and mutator effect of plasmid R46 in Salmonella typhimurium.

Abstract: Plasmid R46 partially protected Salmonella typhimurium, wild type or uvrB or polA, against the lethal effect of ultraviolet (UV) irradiation, but did not protect recA mutants. The plasmid also increased frequency of UV-induced reversion to His+ in all tested his point mutants (wild type for UV sensitivity), including amber, ochre, UGA, missense, and frame-shift mutants. Plasmid R46 also increased UV-induced reversion to His+ in uvrB and polA strains, but no UV mutagenic effect was detected in R- or R46-carrying recA derivatives of a his (amber) mutant. The spontaneous reversion frequency of his nonsense mutants of all classes, and of some his missense mutants, was increased about 10-fold when the strains carried R46, but the plasmid had no effect on the spontaneous reversion frequency of some other his missense mutations or of reversion rate of his frame-shift mutants (except for two uvrB derivatives of one single-base insertion mutant). The plasmid increased the ability of wild-type, polA, and uvrB hosts to support plaque production by UV-irradiated phage, and made strain LT2 hisG46 less sensitive to methyl methane sulfonate and to X rays and more responsive to the mutagenic effect of visible-light irradiation. R46 increased spontaneous reversion frequency of a his (amber) rec+ strain, but had no such effect in its recA sublines. Since the plasmid in the absence of host recA function fails to produce its mutator effect, or to confer UV protection or to enhance UV mutagenesis, these three effects may be produced via some mechanism involved in recA-dependent deoxyribonucleic acid repair, perhaps by an increase in activity of the "error prone" component of the inducible repair pathway.

Reassessment of roles of oxygen and ultraviolet light in Precambrian evolution

Abstract: It is argued that the transition to an oxidizing atmosphere preceded the origin of eukaryotic cells, which in turn must have preceded the origin of metazoa Moreover, the number of methods by which organisms can protect themselves from harmful UV radiation is sufficiently large to suggest that solar UV, even when the atmosphere was anaerobic, was not such as to control the distribution and diversification of life An alternative explanation for the late and sudden appearance of metazoa in lower Cambrian sediments is proposed, which is related to the mechanisms by which fully mature eukaryotic cells probably originated There was probably a protracted evolution of modern genetic systems based on mitosis in cells which acquired organelles (eg, plastids and mitochondria) by hereditary endosymbiosis The origin of hard parts underlies the Cambrian explosion of metazoans

Differential chromatid staining by in vivo treatment as a mutagenicity test system

Abstract: DIFFERENTIAL staining of sister chromatids can be demonstrated with Hoechst 33258 fluorochrome1 and with Giemsa after special pretreatment2, even if 5-bromodeoxyuridine (BUdR) is present during the first S phase only3. These techniques permit the use of the phenomenon of the sister chromatid exchange (SCE). The average spontaneous rate of 10–14 SCEs per metaphase seems to be fairly constant in all cultures from several species4,5. A variety of mutagenic factors (that is, ultraviolet light and alkylating agents) produce very high frequencies of SCE even at concentrations far below the level necessary for the induction of chromosomal breakage, whereas others, like X rays or certain chemicals, hardly influence the rate of SCE6. Because of the high turnover of BrdU in the liver and the physiologically available thymidine, differential chromatid staining has so far only been produced in in vitro systems (cell cultures) and in the chicken embryo.

Transformation of C3H/10T1/2CL8 mouse embryo fibroblasts by ultraviolet irradiation and a phorbol ester.

Abstract: ULTRAVIOLET light is the major cause of human skin cancer, and papillomas and malignant carcinomas have been induced in the skins of rats and mice by repeated exposure to it1–5. Pound6 reported that although a single short exposure of mouse skin to ultraviolet light did not induce any tumours, when the single exposure was followed by repeated applications of croton oil, many tumours were induced. Thus ultraviolet light acted as an initiator in the two-stage process of skin tumour development7,8. X rays can induce oncogenic transformation of cells in culture9,10, and a preliminary report has appeared on the transformation of hamster embryo cells by ultraviolet light11.

Origin of organic compounds on the primitive earth and in meteorites.

Abstract: The role and relative contributions of different forms of energy to the synthesis of amino acids and other organic compounds on the primitive earth, in the parent bodies or carbonaceous chondrites, and in the solar nebula are examined. A single source of energy or a single process would not account for all the organic compounds synthesized in the solar system. Electric discharges appear to produce amino acids more efficiently than other sources of energy and the composition of the synthesized amino acids is qualitatively and quantitatively similar to those found in the Murchison meteorite. Ultraviolet light is also likely to have played a major role in prebiotic synthesis. Although the energy in the sun's spectrum that can be absorbed by the major constituents of the primitive atmosphere is not large, reactive trace components such as H2S and formaldehyde absorb at longer wavelengths where greater amounts of energy are available and produce amino acids by reactions involving hot hydrogen atoms. The thermal reaction of CO + H2 + NH3 on Fischer-Tropsch catalysts generates intermediates that lead to amino acids and other organic compounds that have been found in meteorites. However, this synthesis appears to be less efficient than electric discharges and to require a special set of reaction conditions. It should be emphasized that after the reactive organic intermediates are generated by the above processes, the subsequent reactions which produce the more complet biochemical compounds are low temperature homogenous reactions occurring in an aqueous environment.

Reactivation of herpes simplex virus infection by ultraviolet light and possible involvement of prostaglandins.

Abstract: Herpes simplex infection in the mouse ear was used to investigate whether various treatments would reactivate the disease. Immunosuppressive drugs failed to induce clinical signs of reactivation but irradiation of the skin of the originally infected ear with ultraviolet light or injection of prostaglandin E2 or PBSA into this site, caused reactivation of infection. This was detected by the appearance of infectious virus in the skin 2 to 3 days after these treatments. The results are discussed in relation to the mechanism of herpes reactivation in man.

Incision of ultraviolet-irradiated DNA by extracts of E. coli requires three different gene products.

Abstract: IN most organisms pyrimidine dimers induced in DNA by ultraviolet light are removed by excision which is initiated by a repair-specific endonuclease that recognises the damage and makes a strand incision adjacent to the dimer1–4. Characterisation of excision-defective mutants of Escherichia coli has shown that in this organism early steps of repair are controlled by the uvrA, uvrB and uvrC genes5. Although uvrA and uvrB mutants seem to be incision defective in vivo6,7, it has not been possible to measure any difference in the amount of ultraviolet-endonuclease activity between crude extracts from mutants and wild-type cells8,9. After partial purification of wild-type or uvrC mutant extracts, however, an ultraviolet endonuclease has been identified which is absent from uvrA and uvrB cells9 (in this communication termed the uvrAB endonuclease). The relevance of these results to whole cells is unclear, because recent experiments with permeable cells have shown that uvrA+B+-dependent strand incision requires adenosine-5′-triphosphate (ATP)10–12, whereas the uvrAB endonuclease is independent of ATP2. The aim of the present investigation was to observe ATP-dependent ultraviolet-endonuclease activity in a cell-free system. We report here the characterisation in crude extracts of an ATP-dependent ultraviolet-endonuclease activity from E. coli and conclude that the activity reflects that the enzyme is essential for repair in whole cells. The activity requires the complementary action of the uvrA+ uvrB+ and uvrC+ products and this has been utilised to establish in vitro assays for the individual products of these genes.

Quantitative determination of organic solvent soluble lipofuscin pigments in tissues.

Abstract: Lipofuscin pigment determination in tissue extracts was quantitated by the use of its property of fluorescence. Chloroform: methanol tissue extracts were purified on Sephadex LH-20 columns before quantitative fluorescence measurements of the lipofuscin pigments. Interfering compounds separated by chromatography were retinol and a lower mol wt fluorescent compound. Irradiation of tissue extracts with ultraviolet light was not sufficient to eliminate the interference caused by retinol and the lower mol wt compound. Purified lipofuscin pigments from blood, lung, liver, spleen, brain, heart, and kidney tissues demonstrated distinct fluorescent emission maximum at 435 nm and excitation maxima between 345 and 350 nm.

Studies on bacteriophage distribution: virulent and temperate bacteriophage content of mammalian feces.

Abstract: Freshly voided samples of the feces of cows, pigs, and humans were analyzed for the enumeration of cell-free plaque-forming units (PFU) of coliphages and Salmonella phages. Coliphage PFU counts per gram (wet weight) of feces were found to range from less than 10(1) to greater than 10(7). Salmonella phages were found in three out of five porcine samples, but none were found in the four bovine samples analyzed. Virulent coliphages related to the phiX174/S13 serological group showed some "habitat preference" in that the S13 type of phages was found only in pig feces, whereas the phiX174 type of phages was found only in cow dung. Temperate coliphages were detectable in a majority of samples of both human and porcine origin but were infrequently found in bovine samples. About 80% of the temperate coliphages of fecal origin have been found to be serologically related to phage HK022 (Dhillon and Dhillon, 1973), and all are efficiently inducible by ultraviolet light irradiation. However, considerable diversity with the group was found when the prophage immunity pattern of 10 randomly selected isolates was examined.

Stable lipid peroxidation products in human skin: detection, ultraviolet light-induced increase, pathogenic importance.

Abstract: Products of lipid peroxidation (malonaldehyde, Schiff-bases) were detected in human skin. These products were increased after UV-light exposition, on chronically sun-exposed areas as well as with advancing age. Malonaldehyde cross linked epidermal glucose-6-phosphate-dehydrogenase and diminished their activity.

Properties of adenyl cyclase and cyclic adenosine 3',5'-monophosphate receptor protein-deficient mutants of Escherichia coli.

Abstract: Several spontaneous cya and crp mutants of Escherichia coli have been selected as clones simultaneously resistant to phage lambda and nalidixic acid and characterized. Both cya and crp mutants have been found to grow as cocci with increased doubling times. They have increased resistance to some mutagens (methylmethanesulfonate, ultraviolet light, gamma rays), antibiotics (nalidixic acid, ampicillin), phages (lambda, T6), sublethal heat and hypotonic shock, and decreased resistance to neutral detergents (sodium dodecyl sulfate, sodium deoxycholate), a protein synthesis inhibitor (streptomycin), and a respiratory inhibitor (sodium azide). The nature of changes in cell parameters indicate fundamental alterations in the envelope structure of the cya and crp mutant cells. The new cya and crp mutants have been found to be multiply carbohydrate negative and nonmotile in conformity with similar previously isolated mutants. Studies of revertants and phi 80 cya$sup +$ and phi 80 cya transductants indicated that the pleiotropic phenotype is related to a single mutational event at the cya or the crp locus in the mutants. (auth)

Analysis of the proteins synthesized in ultraviolet light-irradiated Escherichia coli following infection with the bacteriophages lambdadrifd 18 and lambdadfus-3.

Abstract: The presence of EF-Tu, RNA polymerase subunit alpha, and EF-G on the lambdadfus-3 genome and EF-Tu, ribosomal proteins L7/L12, and RNA polymerase subunit beta on the lambdadrifd 18 genome has been confirmed using a two-dimensional gel electrophoresis technique sensitive to changes in isoelectric point and molecular weight. In this system two EF-Tu gene products could not be resolved. Following infection of ultraviolet light-irradiated Escherichia coli with either lambdadfus-3 or lambdadrifd18, the EF-Tu gene, tufA, near 65 minutes on the genetic map is expressed as 3-4 copies per EF-G molecule. The EF-Tu gene, tufB, near 79 minutes on the genetic map, is expressed at about one-third of this rate. alpha is expressed as 1 copy per EF-G molecule, beta as 0.14 per EF-G molecule and L7/L12 as 2.5 per EF-G. These figures compare well with the relative amounts found in exponentially-growing cells, in which the ratio of EF-Tu to EF-G is approximately 5. Almost 90% of the total number of proteins (calculated on a molecular weight basis) which theoretically can be encoded on the lambdadrifd18 have been identified on the two-dimensional gel.

Induction of syncytia by the bovine C-type leukemia virus.

Abstract: Bovine buffy coat cells infected with the bovine leukemia virus (BLV) induce syncytia formation in human diploid embryonic lung cells as well as in monolayer cell cultures of bovine, simian, ovine, bat, and caprine origin, but not in mouse fibroblast cells, normall rat kidney cells, or RSV-transformed rat cells Syncytia were not observed in diploid embryonic lung cells inoculated with bovine buffy coat cells free of BLV The syncytia-induction effect is associated with the synthesis of complete BLV by the buffy coat cells and is independent of whether these cells are viable, disrupted, normal, or malignant Cell-free preparations of BLV and density gradient-purified virus also induce syncytia when added directly to diploid embryonic lung cells and to bovine, bat, and caprine monolayer cell cultures Ether treatment, ultraviolet light irradiation, heating, freezing, and thawing destroy the syncytia-inducing activity of BLV This activity is also neutralized when the virus is incubated with sera containing antibodies to BLV, but not when incubated with sera free of these antibodies or reference serum for the foamy-like bovine syncytial virus Several other lines of evidence rule out the possibility that this virus or other bovine viruses are responsible for the syncytia-inducing phenomenon described here BLV antigen was consistently detected by the immunofluorescent test in the syncytia-positive monolayer indicator cultures However, syncytia formation was not necessarily associated with BLV production by the indicator cells The ability to induce syncytia in monolayer cultures of nontransformed cells distinguishes BLV from all the known C-type luekemia viruses

Chromatid exchanges in ataxia telangiectasia, Bloom syndrome, Werner syndrome, and xeroderrna pigmentosum

Abstract: The frequency of BrdU-induced sister chromatid exchanges (SCE) in cultured lymphocytes from patients with ataxia telangiectasia, Werner syndrome, and xeroderma pigmentosum was normal. The rate was increased in xeroderma pigmentosum following exposure to ultraviolet light and spontaneously raised in the Bloom syndrome. Quadriradial exchanges between homologous chromosomes in Bloom syndrome not only involve sister chromatids but also homologous (non-sister) chromatids. This could result in the formation of recombinant chromosomes and is viewed as a genetically determined form of increased somatic recombination in man. Endoreduplicated metaphases showed 'twin' and 'single' exchanges in a 1:2 ratio. This suggests a comparable frequency of exchanges at both divisions and provides evidence for the polarity of the chromatid subunits and the presence of a single chain of DNA.

Encapsulation by entrapment

Abstract: Water-soluble and water-insoluble solid and liquid core materials are encapsulated by the same method. Core materials are simply entrapped in a matrix of water-insoluble polyhydroxy polymers which are insolubilized from their corresponding water-soluble xanthates in the presence of the core materials. Encapsulation of biologically active compositions provides a shield against hostile environments, improves safety in handling, and slows the release of such compounds to the surrounding medium. Highly volatile liquids are protected against losses by evaporation. Encapsulation also provides protection against decomposition from exposure to ultraviolet light.

Requirements for ingestion of Chlamydia psittaci by mouse fibroblasts (L cells).

Abstract: Ingestion of 14C-amino acid-labeled Chlamydia psittaci (6BC) by mouse fibroblasts (L cells) was inhibited when the host cells were incubated for 30 min at 37 degrees C in Earle salts containing 10 mug of crystalline trypsin per ml. Tryptic digestion also inhibited the ingestion of 1-mum polystrene latex beads. Trypsin-treated L cells almost completely recovered their ability to ingest chlamydiae after 4 h at 37 degrees C in medium 199 with 5% fetal calf serum. Cycloheximide (10 mug/ml) blocked this recovery. Heating 14C-amino acid-labeled C. psittaci for 3 min at 60 degrees C inhibited its ingestion by L cells, whereas inactivating it with ultraviolet light was without effect on the ingestion rate. These results show that efficient ingestion of C. psittaci by L cells involves trypsin-labile sites on the host and heat-sensitive sites on the parasite. The failure of excess unlabeled infectious C. psittaci to promote the ingestion of 14C-labeled heat-inactivated chlamydiae suggests that direct interaction between these two sites must occur for uptake to proceed normally.

Induction of cellular DNA synthesis and increased mitotic activity in syrian hamster embryo cells abortively infected with human cytomegalovirus.

Abstract: Summary The effect of human cytomegalovirus (CMV) on cell DNA synthesis and mitotic activity in hamster embryo fibroblasts was examined. The results indicated that CMV infected cells had increased rates of cell DNA replication and mitotic activity. Detection of the effect of CMV on these two parameters necessitated arrest of cells prior to infection with low serum concentrations. This lowered the background levels of DNA synthesis and cell division so that the effect of virus infection could be detected. The data indicate that cells arrested prior to infection demonstrate increased susceptibility to virus infection. It was also observed that the effect of CMV on both DNA replication and mitotic activity could be enhanced by irradiation with ultraviolet light of the virus prior to infection.

Bullous pemphigoid and psoriasis: does subclinical bullous pemphigoid exist?

Abstract: Four cases are presented in which probable bullous pemphigoid and probable psoriasis co-existed. One case represents a simple coincidence of the two diseases. In the other three cases, the bullous lesions were transient and seemed to be induced by elements of the Goeckerman regimen. The hypothesis is presented that these three cases represent a subclinical form of bullous pemphigoid induced by the irritant effects of coal tar, ultraviolet light, the reduced barrier function of a pre-existing dermatosis, or a combination of these factors.

Method for depositing a metal on a surface

Abstract: The method of depositing a metal on a surface especially suitable for the manufacture of printed circuit boards includes coating the surface with a sensitizing solution comprising an inaqueous solvent solution, a reducible salt of a non-noble metal, a salt of 2,7 anthraquinone disulfonic acid and a polyol type secondary reducing agent such as sorbitol. The coated surface is then dried and the dried surface may be stored for extended periods of time before further processing which consists of imaging the sensitized surface with ultraviolet light and electrolessly plating a metal over the imaged surface.