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At least 235 records · Page 13Linked to original sources
PubMed1997

Induction of mutagenic DNA damage in human fibroblasts after exposure to artificial tanning lamps.

There is increasing concern about the adverse health effects associated with the use of sunbeds, particularly with respect to skin photocarcinogenesis. The induction of mutagenic DNA damage is a prerequisite for the development of skin tumours, and it is well established that direct types of damage such as cyclobutane pyrimidine dimers (CPDs) give rise to mutations in tumour suppressor genes and oncogenes. In addition, ultraviolet radiation may induce indirect types of DNA damage, including oxidative products, which are also potentially mutagenic. By using specific DNA repair enzymes (T4 endonuclease V and endonuclease III) and the comet assay we have been able to detect the induction of CPDs, oxidized or hydrated pyrimidine bases and single-strand breaks in cultured human fibroblasts (MRC-5) after exposure for between 15 s and 20 min on two different commercial sunbeds containing Philips 'Performance' 100W-R or Philips TL80W/10R lamps. The ratio of endonuclease III to T4 endonuclease V sensitive sites varied substantially between the two lamps and was 3.3% and 18%, respectively. The sunbed containing the 'Performance' 100W-R lamps was as potent at inducing CPDs as was natural sunlight in fine weather. These results establish that commercial tanning lamps produce the types of DNA damage associated with photocarcinogenesis in human cells, and complement epidemiological evidence indicating the potential risk of using sunbeds.

Beauty Culture↗
PubMedDate not supplied

[Activity of serum leucine aminopeptidase lamp in normal and pathologic pregnancies].

The activity of the enzyme leucine aminopeptidase (LAmP) in serum was examined in 305 pregnant women (174 women with normal pregnancy, and 131 women with disturbed pregnancy). The activity of this enzyme increases during the normal development of pregnancy. In disturbed pregnancies, the LAmP activity is lower as compared to normal pregnancies. A peculiar case: toxemia of pregnancy, where the activity of the enzyme is considerably increased. This fact may be compared with the increase of LAmP activity in cases of liver damage. The LAmP activity test in pregnancy is reliable and can be performed practically in every laboratory, thus deserving its place among the many tests meant to assess the normal function of the foeto-placental unit. This test may also help in the diagnostic of some specific pregnancies such as twin pregnancy, hydatidiform mole and extra-uterine pregnancy.

Adolescent↗
PubMed1987

Multiple wavelength illumination in flow cytometry using a single arc lamp and a dispersing element.

The principle of a multiple wavelength illumination method for flow cytometers, based upon a combination of a helium-neon laser and an arc lamp as illumination sources is described. By using a prism, the light from the arc lamp is dispersed and the different colors are imaged at different places on the sample stream. The small angle light scattering from the helium-neon laser light is measured as a relevant parameter and serves as a trigger signal for subsequent measurements of fluorescence or scattering of light from the arc lamp. Two experimental systems are described utilizing this principle: a system where the emission is detected orthogonally with respect to the direction of the illumination beams, and an epi-illumination system. With the orthogonal set-up multiple wave-length right angle scattering measurements are possible. This is illustrated by showing that the orthogonal scattering from erythrocytes is strongly dependent on the illumination wavelength. It is further shown that the apparatus is suitable for the measurement of intracellular pH using the pH dependence of the excitation spectrum of fluorescein. The epi-illumination system allows excitation of two (or more) fluorescent dyes with different excitation spectra. In this case the emission spectra of the fluorescent dyes may overlap substantially. This is shown by simultaneous measurement of DNA and protein of Chinese hamster lung cells using mitramycin and tetramethyl rhodamin isothiocyanate (TRITC).

DNA↗
PubMed1993

Pulse modulation of the excitation light source boosts the sensitivity of an arc lamp-based flow cytometer.

It has been found that the type of short arc high-pressure lamps used in some flow cytometers can be pulsed to reach intensities many times higher than that measured when they are operated on constant power. A 75 W mercury-xenon lamp was fed 20 microseconds current pulses super-imposed on its rated current of 5.4 A. Pulses of 50 A produced a 75-fold increase of the emission intensity at the excitation wavelength of FITC, which means that the excitation intensity in the flow chamber at this wavelength exceeded 100 mW. At the major emission lines of mercury, i.e., 366, 436, and 546 nm, the increase was about 25-fold, corresponding to intensities of the order of 300 mW. The light pulses were found to be reproducible to within 2% and the intensity was independent of the pulse frequency up to at least 250 pulses/s. Operated in this mode the lamp produced more than 1 x 10(8) 30 A pulses, which is sufficient to measure some 10,000 typical size samples. The rise time of the light pulses was about 5 microseconds. This was sufficiently short that the leading edge of the light scattering signal from a cell entering the excitation focus of the flow cytometer could be used to trigger the current pulse so that the cells were exposed to the full light pulse intensity while they were still within the focus.(ABSTRACT TRUNCATED AT 250 WORDS)

Flow Cytometry↗
PubMed2005

Extracellular lysosome-associated membrane protein-1 (LAMP-1) mediates autoimmune disease progression in the NOD model of type 1 diabetes.

Treatment (from 5 to 25 weeks of age) with a novel blocking monoclonal antibody, mAb I-10, directed against the plasma membrane (pm) form of LAMP-1, protected against development of autoimmune diabetes in the NOD mouse. A shorter course of treatment, i.e. from 5 to 12 weeks of age, significantly reduced the occurrence of insulitis as well as disease onset. Interfering with pm-LAMP-1 required continuous treatment as tolerance was not observed when treatment was stopped, and no higher proportion of cells with a T regulatory phenotype (e.g. CD4(+)CD25(+)) were induced. The mechanism appears to involve modulating a proinflammatory cytokine, as the proportion of pancreatic-infiltrating IFN-gamma-positive cells was significantly reduced in the mAb I-10-treated group. These results demonstrate an unexpected role for pm-LAMP-1 in autoimmune disease progression, and suggest that further investigation should be performed to understand how this molecule modulates IFN-gamma-driven responses.

Amino Acid Sequence↗
PubMed1993

Slit lamp laser Doppler interferometer.

A slit lamp laser interferometer is described for clinical in vivo eye length measurements. The basic components are a laser Doppler interferometer, a slit lamp attachment, and a commercial slit lamp. First measurements of the axial length of the eye yielded a standard deviation of 0.04 mm and less.

Eye↗
PubMed2003

Differential expression of lysosomal associated membrane protein (LAMP-1) during mammalian spermiogenesis.

The mammalian acrosome is a secretory vesicle of mature sperms that plays an important role in fertilization. Recent evidence had pointed out that some components found at endosomes in somatic cells are associated with the developing acrosome during the early steps of spermiogenesis. Moreover, the mammalian acrosome contains many enzymes found within lysosomes in somatic cells. In this work, we studied the dynamics of some components of the endosome/lysosome system, as a way to understand the complex membrane trafficking circuit established during spermatogenesis. We show that the cation independent-mannose-6-phosphate receptor (CI-MPR) is transiently expressed in the cytoplasm of mid-stage spermatids (steps 5-11). On the other hand, gamma-adaptin, an adaptor molecule of a complex involved in trafficking from the Golgi to lysosomes, was expressed in cytoplasmic vesicles only in pachytene and Cap-phase spermatids (steps 1-5). Our major finding is that the lysosomal protein LAMP-1 is differentially expressed during spermiogenesis. LAMP-1 appears late in spermatogenesis (Acrosome-phase) contrasting with LAMP-2, which is present throughout the complete process. Both proteins appear to be associated with cytoplasmic vesicles and not with the developing acrosome. None of the studied proteins is present in epididymal spermatozoa. Our results suggest that the CI-MPR could be involved in membrane trafficking and/or acrosomal shaping during spermiogenesis.

Acrosome↗
PubMed2006

Novel Lamp-2 gene mutation and successful treatment with heart transplantation in a large family with Danon disease.

Lysosome-associated membrane protein-2 deficiency (LAMP-2 deficiency), or Danon disease, is a rare X-linked lysosomal disease characterized by cardiomyopathy, vacuolar myopathy, and mental retardation. Less than 20 families with mutations of the Lamp-2 gene have been reported. We describe a family from Sardinia with eight affected patients (4 females and 4 males) and a novel mutation in exon 2 of the Lamp-2 gene (c.102_103delAG). Females developed isolated cardiomyopathy in adulthood, whereas males presented with cardiomyopathy, myopathy, and mental retardation before the age of 20 years. Cardiomyopathy was lethal in three females in their 40s and in three males before the age 20 years. One patient was successfully treated by heart transplantation with more than 5-year follow-up. This study demonstrates that Danon disease is a frequently fatal condition that is potentially treatable with heart transplantation.

Adult↗
PubMed1998

Mercury vapour lamps interfere with the bat defence of tympanate moths (Operophtera spp.; Geometridae)

Bats often forage near streetlamps, where they catch moths in particular. At least two hypotheses may explain the apparent increase in the availability of moths to bats feeding around streetlamps: (1) the moths become concentrated near the light and therefore more profitable to exploit; and (2) the light interferes with the moths' evasive flight behaviour. We tested the second of these hypotheses by exposing flying male winter moths, Operophtera spp., to bursts of ultrasound (26 kHz, 110 dB sound pressure level) from an electronic source. The light from a 125 W mercury vapour lamp had a quantitative effect on the moths' evasive flight response at close range (within ca 4 m), inhibiting it totally in nearly half (43%, N=125) of the cases. By contrast, moths flying in the surrounding woodland and without interference from the lamp always responded to the sound. Streetlamps of the mercury vapour type (white lamps) thus interfere with the defensive behaviour of moths and presumably increase their vulnerability to echolocating bats. This may have implications for the conservation of both moths and bats. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1996

Soluble form of Lamp II in purified rat liver lysosomes.

Lamp II (for lysosomal associated membrane protein II) is an integral type I glycoprotein. It consists of a very large and heavily glycosylated luminal domain, a single transmembrane segment, and a short cytoplasmic tail. We show that in highly purified lysosomes from rat liver, Lamp II, immunodetected with a monoclonal antibody on Western blots, it surprisingly distributed between a membrane bound form and a "soluble" form. The partition of the protein between the membrane and the content of lysosomes is strongly pH dependent. The soluble Lamp II population is sensitive to pH dependent aggregation as it is for many lysosomal content enzymes.

Animals↗
PubMed1994

Double labelling of major histocompatibility complex molecules and lysosomal protein lamp-1 on human dendritic cells.

In this study, double labelling for major histocompatibility complex (MHC) class I and class II molecules and for MHC molecules and the lysosomal membrane protein lamp-1 on ultrathin cryosections of dendritic cells isolated from human peripheral blood was performed. The plasma membrane proved to be positive for both MHC class I and MHC class II molecules and was labelled for only a very few lamp-1 molecules. MHC class I and MHC class II molecules did not co-localize intracellularly except in some peripherally located vesicles. However, many MHC class II-labelled vesicles were present in a juxtanuclear position but only some of them were co-labelled for lamp-1. These results indicate the presence of a separate, non-lysosomal compartment for class II molecules in dendritic cells.

Antigens, CD↗
PubMed1985

Photometric oculometry: a slit-lamp technique for determination of intraocular distances.

The optics of slit-lamp fluorophotometry were analyzed. This analysis forms the basis of the formulation of a slit-lamp technique called photometric oculometry, which makes it possible to measure intraocular distances. A comparison between ultrasonography and photometric oculometry in the determination of the ocular axial length was carried out. Measurements in 11 eyes showed statistical agreement, with a mean of 22.90 mm, SD +/- 1.815 (ultrasound), and a mean of 23.17 mm, SD +/- 1.667 (photometry). The principle involved in photometric oculometry is of special importance for the calculation of the blood-retinal barrier permeability to fluorescein by vitreous fluorophotometry, since the method allows the volume of the vitreous body to be estimated directly from the slit-lamp fluorophotometer recording.

Eye↗
PubMed2003

Detection of Japanese yam mosaic virus by RT-LAMP.

Arapid and simple procedure is described to detect the genomic RNA molecule of Japanese yam mosaic potyvirus (JYMV). This method, named RT-LAMP, allows direct detection of RNA from infected plants without careful RNA extraction, rapid thermal cycling and gel electrophoresis. RT-LAMP was successfully applied to leaves, propagules and roots of Japanese yam infected with JYMV. One of the characteristics of the RT-LAMP method is its ability to synthesize an extremely large amount of DNA. Accordingly, a large amount of by-product, pyrophospate ion, is produced yielding a white precipitate of magnesium pyrophosphate in the reaction mixture. The presence or absence of this white precipitate allows easy detection of the amplification of JYMV genomic RNA without gel electrophoresis.

Base Sequence↗
PubMed2006

Phototoxic effects of commercial photographic flash lamp on rat eyes.

BACKGROUND: To determine whether exposure of the cornea and retina of rats to flashes from a commercial photographic flash lamp is phototoxic. METHODS: Sprague-Dawley rats were exposed to 10, 100, or 1,000 flashes of the OPTICAM 16M photographic flash lamp (Fujikoeki, Japan) placed 0.1, 1, or 3 m from the eyes. Corneal damage was assessed by a fluorescein staining score, and the retinal damage by eletroretinography (ERG) and histology before and 24 h after exposure. RESULTS: Exposure of the eyes to 1,000 flashes at 0.1 m increased the fluorescein staining score significantly (P = 0.009, the Mann-Whitney test). Scanning electron microscopy (SEM) of the cornea showed a detachment of the epithelial cells from the surface after this exposure. The amplitude of the a-wave was decreased significantly by 23.0% (P = 0.026) of the amplitude before the exposure, and the b-wave by 19.7% (P = 0.0478) following 1,000 flashes at 0.1 m but not by the other exposures. TUNEL-positive cells were present in the outer nuclear layer only after the extreme exposure, but no significant decrease in retinal thickness was seen under any condition. The fluorescein staining score and ERGs recovered to control levels within 1 week. CONCLUSIONS: Light exposure to a photographic flash lamp does not induce damage to the cornea and retina except when they are exposed to 1,000 flashes at 0.1 m.

Animals↗
PubMed1991

A linearized DC lamp controller.

The design of a simple and inexpensive battery powered lamp controller for microscope lamps commonly used in patch clamp and other biophysical studies is described. The circuit linearizes the normally exponential voltage-intensity curve of standard 12-V lamps by using an operational amplifier to provide feedback to the drain of a power MOSFET. When the unit is turned off, a charging circuit recharges the battery at a constant potential until the battery voltage reaches a preset level. The charging voltage is then reduced to balance the self-discharge rate of the battery.

Amplifiers, Electronic↗
PubMed2005

Improved vacuum-UV (VUV)-initiated photomineralization of organic compounds in water with a xenon excimer flow-through photoreactor (Xe2* lamp, 172 nm) containing an axially centered ceramic oxygenator.

Xenon excimer (Xe2*) lamps can be used for the oxidation and mineralization of organic compounds in aqueous solution. This vacuum-ultraviolet (VUV) photochemical method is mainly based on the photochemically initiated homolysis of water that produces hydrogen atoms and hydroxyl radicals. The efficiency of substrate oxidation and mineralization is limited markedly due to the high absorbance of water at the emission maximum of the Xe2* lamp (lambda(max)=172 nm). This photochemical condition generates an extreme heterogeneity between the irradiated volume V(irr) and the non-irradiated ("dark") bulk solution. During VUV-initiated photomineralization of organic substrates, the fast scavenging of hydrogen atoms and of carbon-centered radicals by dissolved molecular oxygen produces a permanent oxygen deficit within V(irr) and adjacent compartments. Hence, at a constant photon flux the concentration of dissolved molecular oxygen within the zones of photo and thermal radical reactions limits the rate of mineralization, i.e. the rate of TOC diminution. Thus, a simple and convenient technique is presented that overcomes this limitation by injection of molecular oxygen (or air) into the irradiated volume by use of a ceramic oxygenator (aerator). The tube oxygenator was centered axially within the xenon excimer flow-through lamp. Consequently, the oxygen or air bubbles enhanced the transfer of dissolved molecular oxygen into the VUV-irradiated volume leading to an increased rate of mineralization of organic model compounds, e.g. 1-heptanol, benzoic acid and potassium hydrogen phthalate.

Equipment Design↗
PubMed2006

Real-time quantitative LAMP (loop-mediated isothermal amplification of DNA) as a simple method for monitoring ammonia-oxidizing bacteria.

Loop-mediated isothermal amplification (LAMP) of DNA is a novel technique for the amplification of DNA under isothermal conditions. For the first time, we applied this method to develop a simple and quantitative monitoring method for environmental microorganisms targeting amoA gene in ammonia-oxidizing bacteria. Quantitative analysis was performed first by measuring fluorescence derived from an intercalation dye using a real-time thermal cycler, and then by measuring the turbidity of the reaction solution using a real-time turbidimeter. As a result, it was possible to quantify the initial amoA DNA concentration from an environment with a sensitivity down to 10(2) DNA copies of target DNA and a dynamic range of 7-9 orders in magnitude. Background DNA from nontargeted bacteria (Pseudomonas denitrificans) that does not encode amoA gene did not affect the quantitative capability of LAMP. Over results suggested that the real-time LAMP is effective for monitoring microorganisms and their gene expression in environments.

Ammonia↗
PubMed2004

Rapid detection of a fish iridovirus using loop-mediated isothermal amplification (LAMP).

A loop-mediated isothermal amplification (LAMP) procedure is described to detect the genomic DNA molecule of red seabream iridovirus (RSIV), a fish iridovirus belonging to the Iridoviridae family. The RSIV DNA was amplified using DNA extracts obtained from spleen of infected red seabream, Pagrus major and from various RSIV isolates. The method was at least 10 times more sensitive than conventional PCR in detecting for the presence of RSIV. A striking feature of the LAMP reaction is its ability to synthesize a large amount of DNA leading to the production of a white precipitate, magnesium pyrophosphate, as a by-product. The presence or absence of this white precipitate facilitates easy detection of the RSIV genomic DNA without the use of gel electrophoresis. A strong correlation exists between the amount of input viral DNA copy and the corresponding turbidity reading at the end of the reaction; hence, the LAMP reaction may be used potentially to quantify RSIV particles in the infected fish.

Animals↗