Blue Fluorescent Light Research Articles

Evidence that the replication point is the site of sister chromatid exchange

DNA synthesis in Chinese hamster cells was blocked partially by treating the cells with either fluorodeoxyuridine (FUdR) or cycloheximide (CHM) for various lengths of time. Analyses of the population kinetics and measurement of incorporation of labeled nucleosides during the FUdR block strongly suggested that the number of growing points was accumulated by the treatment while the rate of chain growth was greatly reduced. No evidence for such an accumulation was obtained in the CHM-treated cells. To study the relation between DNA replication and sister chromatid exchange (SCE), bromodeoxyuridine-labeled cells were exposed to blue fluorescent light while DNA synthesis was blocked. The frequency of SCE induced by the light treatment appeared to increase as the number of growing points increased, implying that the site of exchange is confined to the replication forks. The induction of SCE by fluorescent light was inhibited completely by CHM-treatment. The reason for this finding remains to be elucidated.

214 EFFECT OF LIGHT ON THE PERFUSED GUNN RAT LIVER

The livers of 6 Gunn rats (200 gm.), 3 jj and 3 Jj, were perfused for 1 hr. with std. KBR soln. to which bilirubin in conc. of 20 mg/dl was added to 4. One jj and 1 Jj were perfused in the dark, 2 each in blue fluorescent light (420-470 nm, 18 μw/cm2/nm) Bilirubin was extracted in CCl4 from half of each liver, the other half analyzed for activity of: cytochrome P450, b5, p-nitrophenol glucuronidation, benzo(a)pyrine and analine hydroxylation, aminopyrine demethylation. All livers perfused with KBR-bili. or KBR alone under light had little or no bilirubin at end of perfusion. Those perfused in the dark had significant amounts of bilirubin. Assays of both jj and Jj rat livers showed a marked increase in activity of all 6 enzymes, 40+ percent. As all rats were female, no intersex variable was encountered. Determination of bilirubin conc. of outflow KBR-bili. perfusate showed a small but significant decline q5 min. during perfusion. Bilirubin extract from livers of both jj and Jj rats in the dark was in high conc. We conclude that visible light penetrates through the intact rat liver, directly photodegrading bilirubin, possibly enhancing its uptake. These data further indicate that visible light (420-470 nm) induces hepatic cell enzyme activity. The possibility exists that visible light irradiation, as in phototherapy, will enhance drug metabolism by hepatic cell enzyme induction.

1026 COMPARISON OF INCANDESCENT AND FLUORESCENT LIGHT SOURCES IN PHOTOTHERAPY

The purpose of this study was to determine the efficiency of an incandescent light source of high intensity in phototherapy of neonatal jaundice in comparison with a standard fluorescent source. Forty well infants with physiologic jaundice (1810-3320 gm.) were assigned at random to two groups of 20 each: Gp. A under a quartz-halide tungsten filament lamp (6.5 μW/cm2/nm) 80 cm. above skin surface, next to a radiant warmer; Gp. B under a canopy of 8 standard blue (F20T12/B) lamps (4.1 μW/cm2/nm.) 45 cm. above skin surface. Phototherapy was begun when serum bilirubin concentration exceeded 10.0 mg/dl in first 72 hr of life. In Gp. A, phototherapy was stopped when conc. <80 mg/dl. In Gp. B, this was done in two-thirds of infants, but stopped p 36 hr. in one-third because of failure of phototherapy. In Gp. A mean hr. Rx = 41.5, mean bili. drop 1.92 mg/dl/24 hr.*We conclude that the quartz-halide lamp placed high above the infant is more effective in the clinical use of phototherapy than the standard blue fluorescent light source. It has spatial advantage and lack of light scatter. Body temperatures in Gp. A were not increased by use of the quartz-halide lamp.*In Gp. B mean hr. Rx = 46.7 , mean bili. drop 0.48 mg/dl/24 hr.

A fluence response study of lethality and mutagenicity of white black, and blue fluorescent light, sunlamp, and sunlight irradiation in Chinese hamster ovary cells

Under a set of defined experimental conditions, the fluence response of Chinese hamster ovary (CHO) cells to various light sources was studies by measuring single-cell survival and mutation to 6-thioguanine (TG) resistance. Fluorescent white, black, and blue lights were sightly lethal and mutagenic. Sunlamp light was highly lethal and mutagenic, exhibiting these biological effects within 15 sec of exposure under conditions recommended by the manufacturer for human use. Lethal and mutagenic effects were observed after 5 min of sunlight exposure; responses varied with hourly and daily variations in solar radiation. Sunlight-induced TG-resistant variants possessed <5% of parental cellular hypoxanthine-guanine phosphoribosyl transferase (HGPRT) enzyme activity, suggesting that the mutation induction occurs at this locus. The cell survival and mutation-induction curves generated by exposure of cells to both sunlamp and sunlight were similar to those obtained by the use of a standard far-UV lamp.

Crossability of some green-peach-aphid-resistant tuber-bearing solanums, potential bridging species, andSolanum tuberosum ssptuberosum

Blue light fluorescence microscopy was found to be a quick and easy procedure for assessing pollen tube development in interspecific pollinations ofSolanum. Based on penetration of pollen tubes to the base of the style, several combinations of green-peach-aphid-resistant species and potential bridging species to S.tuberosum ssp.tuberosum should be considered for embryo culture. Sterile or highly infertile hybrids were obtained between green-peach-aphid-resistantS. tuquerrense andS. tuberosum ssp.tuberosum and are described. Slightly fertile hybrids were obtained betweenS. tuquerrense andS. polytrichon, a species compatible withS. tuberosum ssp.tuberosum.

Computer files and analyses of laboratory data from tuberculosis patients. II. Analyses of six years' data on sputum specimens.

Laboratory data on sputum specimens from patients with pulmonary mycobacterioses between 1968 and 1973 were analyzed. Specimens were cultured on Middlebrook 7H10 and/or 7H11 medium; blue light fluorescence microscopy was used to examine specimen smears. An admission series of 6 sputum specimens detected 94.7 per cent of all culture-positive patients. Only 62 per cent of patients who were culture positive in the admission series would have been detected by smear alone. Quantitative agreement of smear and culture results was seen only in the smear-numerous (more than 2 bacilli per high-power field), culture-numerous (more than 100 colonies per plate) category. Qualitative agreement of smear and culture was 71 per cent. A total of 123 smear-positive and culture-negative specimens, representing 9 per cent of the total number of positive smears, was found among 6,251 sputum specimens from 270 culture-positive ptients. At least one smear-positive and culture-negative specimen was obtained from 23 per cent of the patients evaluated. During this period, improved housekeeping measures and drying of culture plates reduced the culture contamination rate from 9.8 to less than 5 per cent.

Platelet injury during phototherapy

Phototherapy with blue fluorescent light is widely employed for treatment of neonatal hyperbilirubinemia. Functional, biochemical, and morphologic changes produced by blue fluorescent light in human platelets were identified and characterized. Platelet-rich plasma was exposed for up to 170 min to amounts of light equivalent to that used in phototherapy of neonatal hyperbilirubinemia. Within 110 min of light exposure, platelets were essentially no longer aggregable by ADP and connective tissue suspension and were depleted of ADP, ATP, and glycogen. Electron photomicrographs revealed these platelets to be swollen, depleted of glycogen granules and organelles, and to have ill-defined membranes. Platelet injury could be accelerated by adding a photosensitizing agent, hematoporphyrin, to platelet samples before exposure. In contrast, control platelets kept in the dark for 170 min or nonirradiated platelets resuspended in irradiated plasma maintained their integrity. The results indicate that platelets are damaged in vitro when exposed to amounts of blue light used in phototherapy.

Interacting Effects of Light and Temperature on Sporulation of Peronospora tabacina on Tobacco Leaves

The interacting effects of light and temperature on spore formation of P. tabacina on tobacco leaves were investigated. The following points indicated that an enzymic build-up of an antisporulant during a wet light period and its enzymic decay over a dry dark period may explain the inhibitory effect of light upon sporulation, and its reversal by darkness. (1) Fluorescent blue light of relatively low photon flux density (3 �7 /lE m - 2 S -1) inhibited sporulation by 99 % at 20oe. (2) Light level and temperature during the sporulation period determined spore yield of the pathogen: at high temperatures (in the range 8-24�C) sporulation was inhibited at low light level, whilst no inhibition occurred at much higher light levels at low temperatures. (3) Preceding dry dark treatments given at 200e considerably diminished the inhibitory effect of light, but not if given at 100e. (4) The diffusion of an inhibitory compound from irradiated to unirradiated areas of detached leaves was demonstrated. (5) The continuing photosynthetic activity of the host in the light at 20oe, and the lack of sucrose following dark periods at lOoe, were not associated with the inhibitory effect of light. The similarity between the role of light in the present system and the role of light in activation and decay of phenylalanine ammonia-lyase is discussed.

Activation of hepatic microsomal glucuronyltransferase from gunn rats by exposure to light

Exposure of hepatic microsomes from icteric and nonicteric rats to 250 foot candles of blue fluorescent light for 4 hours at 4–6°C significantly increased the activity of UDPglucuronyltransferase activity using p-nitrophenol as a substrate. The light exposure reduced serum bilirubin concentration from icteric rats or bilirubin of fortified human serum albumin by 70 per cent but there was no difference in light activation of hepatic microsomes from icteric or nonicteric rats. Light exposure also decreased the activation of UDPglucuronyltransferase produced by Triton X-100.

The urinary concentrating defect in the Gunn strain of rat. Role of bilirubin.

The role of high serum and tissue levels of unconjegated bilirubin in the pathogenesis of the impaired urinary concentrating ability was investigated in homozygous (jj) Gunn rats with the congenital absence of hepatic glucuronyl transferase. Continuous phototherapy with blue fluorescent lights at a wave length of 460 nm or oral cholestyramine feeding or both reduced serum levels of unconjugated hilirubin to levels consistently below 3.0 mg/100 ml for several weeks in both weanling and adult jj Gunn rats. The renal concentrating defect was already present in weanling jj Gunn rats by 21 days of age. In treated weanling jj animals, maximum concentrating ability and the concentration of urea and nonurea solutes in the papilla and medulla, determined after 24 h of fluid deprivation, were normal when compared to unaffected heterozygous (Jj) littermates. Solute-free water reabsorption which is reduced in jaundiced jj Gunn rats was restored to normal in treated weanling jj rats. The tissue concentration of unconjugated bilirubin was reduced throughout the papilla and inner and outer medulla in the treated jj rats in comparison with untreated jj littermates. The defect in urinary concentrating ability was only partially reversible and sometimes irreversible in adult jj rats, probably because of permanent renal parenchymal damage occurring secondary to massive crystalline deposits in the papilla and medulla. It is concluded that unconjugated bilirubin is directly involved in the pathogenesis of the concentrating defect in jaundiced jj Gunn rats.

Studies on Auxin Protectors XII. Auxin Protectors and Polyphenol Oxidase in Developing Coffee Fruit

AbstractThe fruit of the coffee plant (Coffea arabica) was analyzed for auxin protector content. Ripe coffee berries were separated into pit and pulp, ground in buffer, and assayed for auxin protectors. The extracts were then subjected to gel filtration in order to determine the molecular weight of the protector(s). In the pit, a single protector was found with a molecular weight approaching 5000 daltons, while the pulp contained several auxin protectors, the largest of which appeared to be about 1000 daltons. Chromato‐graphic studies of various gel filtration fractions showed that protector activity was always associated with spots which exhibited a light blue fluorescence under UV.The changing patterns during coffee fruit development were also investigated. Auxin protector production, and polyphenol oxidase (E.C. 1.10.3.1), an enzyme related to protector metabolism, were assayed at weekly intervals. In the unripe berry, an auxin protector was found with a molecular weight exceeding 200,000 daltons; as the berry ripened the amount of this protector gradually decreased until almost none was present in the ripe berry and the pattern changed to the pattern described above. Polyphenol oxidase content decreased as the berry ripened.Commercially roasted pits, i.e., coffee “beans”, contained very high levels of protector activity. However, gel filtration studies showed this activity to be associated entirely with low molecular weight compounds.

Influence of Radiant Energy from Fluorescent Light Sources on Growth, Mortality, and Feed Conversion of Broilers ,

Experiments were conducted to investigate the effects on growth, feed conversion and mortality of broilers under white incandescent lamps and fluorescent light sources which emitted predominantly radiant energy representing the blue, green, yellow and red portions of the light spectrum.Based on four trials 9 week old broilers under either the blue or green fluorescent light were the heaviest and the lightest were those under the red light. The white incandescent and yellow fluorescent groups were in between the two extremes in regards to weight.Neither feed conversion nor mortality were influenced by light treatment.

Fluorescence Properties of Fluorescamine-Protein Conjugates

Abstract Fluorescamine reacts rapidly with proteins to produce conjugates having A light blue fluorescence. The quantum yields of various conjugates were found to differ significantly, and the measured lifetimes at 25° ranged from 6 to 9 nsec. The yields were highly temperature-dependent. Fluorescence polarization datA show energy transfer between fluorescamine moieties in albumin conjugates. Rotational relaxation times determined from depolarization measurements in good agreement with values reported in studies of proteins labeled with conventional dyes. In water, the fluorescamine derivates of amino acids have lower quantum yields and lifetimes than found in protein conjugates. A blue shift and an increase in quantum yield accompany reduction of solvent polarity, but the spectral shift is quite small. The implications of these datA for the assay of protein amino groups and for protein studies are discussed.

Effects of early postnatal pinealectomy on adult brain and divisional pituitary weights in relation to type of illumination.

Female S1 rats, pinealectomized (p), sham-operated (s) or not operated (n-o) 2–4 days postnatally, were placed at weaning (age = 20–23 days) in individual activity-monitoring cages under blue, green or red fluorescent lights. Photoperiod (LD 12:12) timing was reversed at 2–3 week intervals until autopsy at 293–299 days. In p as compared with s and n-o animals, the brains were lighter and the pituitary glands were heavier. This difference was significant in pars distalis, pars intermedia and the colloid in the residual lumen. Neurohypophyseal weight, however, was significantly greater in both p and n-o than in s animals, suggesting a reversal of a traumatic effect by pinealectomy. Although most of these effects were most significant or marked in the blue-lighted animals, the results are not inconsistent with dependence on known spectral sensitivity of the rat's retinal rhodopsin. However, the results contradict the idea that all effects of pinealectomy are necessarily greater in, or depend upon, reduced il...

藻類の発癌に関する研究-II

In the previous paper1), we reported that the sea bottom mud, heavily polluted by wastes discharged from the coal chemical industry in Ohmuta city in Kyushu, induced a certain cancerous disease to marine alga, Porphyra tenera after a single contact for only 80 to 320 min. and successive 36 day culture. In the present study, acids, neutrals and bases were separated from the same mud and subjected to carcinogenesis tests using very young Porphyra tenera. The tests revealed the carcinogenic effect of the mud to be mainly attributable to the neutrals in it. The neutrals were separated into nine fractions by repeated thin layer chromatography utilizing silica gel containing 5% gypsum for the stationary phase and n-hexane-ether 19:1 mixed solvent as the mobile phase, and two compounds were found to be carcinogenic to this alga; one, the yellow crystals with green fluorescence having an Rf value of 0.20 and another, an orange liquid with light blue fluorescence possessing an Rf value of 0.82.

Neue fluorimetrische bestimmung von testosteron aus dem urin durch dünnschichtchromatographische direktauswertung

New fluorimetric determination of urinary testosterone by thin-layer densitometry Testosterone ane epi-testosterone were separated on thin layers of aluminum oxide. After heating the plates for 20 min at 180° testosterone and other Δ Δ-3-ketosteroids are characterized in long-wave ultraviolet light (366 nm) by a light blue fluorescence (λ max. = 440 nm). This new reaction is very sensitive and allows the determination of small amounts of urinary testosterone by means of thin-layer densitometry without preliminary purification. The lower limit of detection was found to be about 5 ng.

Retinal changes produced by phototherapy

This study was undertaken to assess the effect of blue fluorescent light on retinas of a pigmented, diurnal animal, the newborn piglet. The animals, having one eye shielded, were placed under a phototherapy unit as used for newborn infants. Three weeks after exposure, under light microscopy, the tissues of eyes exposed for 72 hours, and in one instance for slightly less than 12 hours, showed marked damage to the photoreceptors (rods and cones). Under electron microscopy, changes in the visual receptors were observed in the exposed eyes which were not observed in the shielded eyes. High-intensity blue fluorescent light was shown to damage the retinas of newborn piglets, developmentally similar to those of human infants. Therefore, utmost care would seem to be required to shield the eyes of infants exposed to bilirubin phototherapy units.

Titers of antilymphocytic sera determined by immunofluorescence.

The antibody titers of canine antilymphocytic sera from the horse and rabbit were measured by indirect immunofluorescence by reacting the antilymphocytic sera with canine lymphocytes, then attaching labeled antihorse globulin (IgG) to the lymphocyte-antibody complex. This method is sensitive and specific, and the titers correlate closely with titers obtained by the cytotoxicity test. It has practical advantages. It is complement-independent and obviates the need for viable cells. Many smears can be prepared from a single cell preparation, air-dried, and stored for future use. The membranes, the antigenic parts of the cells, fluoresce light green and are quite distinguishable from the nonfluorescing nuclei when viewed with blue-light fluorescence through either a brightfield or a darkfield condenser. Because this reaction is an expression of an antigen-antibody union in a nonviable state, if adequate controls are used to detect nonspecific reactions, false-positive findings are eliminated. (However, in this study nonspecific reactions were not found.)

Studies on the effect of phototherapy on neonatal hyperbilirubinemia among low-birth-weight infants. I. Skin color

A N u M BER of publications have appeared describing the use of blue fluorescent lights in the clinical management of jaundice in the newborn infant. The decrease of serum bilirubin could be caused by the photooxidation of bilirubin in the skin 1, 4 or by displacement of bilirubin outside the vascular space by alteration of the protein binding of bilirubin by the phototherapy, s Since infants with different skin color may show a dissimilar response to phototherapy, it appeared important that controlled studies on the effects of light should be carried out in both Caucasian and Negro babies.

Studies of the pigments in the shrimp Crangon crangon (Crustacea: Malacostraca)

The material examined consisted of adult specimens (male and female) of the shrimp Crangon crangon (L.) collected during the summer of 1967 from the Gdansk Bay of the Baltic Sea. Column and thin-layer chromatography was used for the separation of the carotenoids. The ester compounds and protein complexes of carotenoids were hydrolized with 15% KOH in methanol at room temperature in a nitrogen atmosphere for 48 h. The absorption maxima of the various fractions and spots were determined on the spectrophotometer “Specol” after eluation. The identification of the carotenoids was based mainly on the absorption maxima in appropriate organic solvents and on the Rt values. The acetone extract from the Crangon crangon specimens gave a light blue fluorescence and absorption maxima at wavelengths of 447, 463, 595 to 596 and 667 mμ. The following carotenoids were found to be present in the adult specimens of Crangon crangon: β-carotene, cantaxanthin, astaxanthin, free and esterified lutein, zeaxanthin, and a form of xanthophyll which was not precisely identified. In addition to the above, biliary dyes were also found, probably of the mesobiliviolin and mesobilirhodin type.