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Photoreactivation of Legionella pneumophila after inactivation by low- or medium-pressure ultraviolet lamp.

Photoreactivation of Legionella pneumophila after the inactivation by low-pressure (LP) or medium-pressure (MP) UV lamp was investigated in comparison with that of Escherichia coli. An endonuclease sensitive site (ESS) assay was used to determine the number of UV-induced pyrimidine dimers in the genome DNA of L. pneumophila or E. coli, while the survival ratio of each bacterium was also investigated by cultivation methods. L. pneumophila performed photoreactivation with almost complete repair of pyrimidine dimers associated with the quick recovery of survival ratio. A 3 log inactivation of L. pneumophila by LP or MP UV lamp was, respectively, resulted in 0.5 log or 0.4 log inactivation when photoreactivation was completed. Interestingly, L. pneumophila performed equivalent photoreactivation after LP and MP UV lamp exposures while photoreactivation of E. coli was significantly repressed after the inactivation by MP UV lamp. This study indicated that an attention would be required to design and operate a UV disinfection system targeting L. pneumophila. It was further implied that E. coli would not correctly indicate the fate of L. pneumophila in UV disinfection systems when photoreactivation takes place.

DNA, Bacterial↗

On focusing the slit-lamp: Part II. "The fading-slit test"--verifying the ocular setting.

The focusing-rod test is considered the gold standard for determining the correct setting of the slit-lamp ocular rings. This method is, however, somewhat time-consuming, considering the time it often takes to locate a rod every time one switches between slit-lamps or slit-lamp-mounted lasers. In this article we present an alternative test, which we call the fading-slit test, that requires only a second to perform, does not involve additional equipment (such as a rod), and can be applied at any time during the slit-lamp examination. However, while the focusing-rod test determines what setting should be used, the fading slit test can verify only whether the current setting is indeed the correct one and, therefore, it is not a complete substitute for the focusing-rod test. The fading-slit test is performed as follows: while focusing on any approximately flat surface (even the center of the patient's dome-shaped cornea would do) and using oblique illumination, gradually reduce the slit width until it disappears. Pay attention to whether the slit continuously thins, reaching a hairline width prior to its disappearance or, alternatively, whether, just before disappearance, the slit remains somewhat wide, gradually fading away, instead of thinning away. In the former case the ocular setting is correct; in the latter case it is incorrect.

Calibration↗

Distinct domains of the limbic system-associated membrane protein (LAMP) mediate discrete effects on neurite outgrowth.

The limbic system-associated membrane protein (LAMP) is a glycosylphosphatidylinositol-anchored glycoprotein with three immunoglobulin (Ig) domains that can either enhance or inhibit neurite outgrowth depending upon the neuronal population examined. In the present study, we investigate the domains responsible for these activities. Domain deletion revealed that the N-terminal IgI domain is necessary and sufficient for the neurite-promoting activity observed in hippocampal neurons. In contrast, inhibition of neurite outgrowth in SCG neurons, which is mediated by heterophilic interactions, requires full-length LAMP, although selective inhibition of the second Ig domain, but not the first or third domains, prevented the inhibitory effect. This indicates that the IgII domain of LAMP harbors the neurite-inhibiting activity, but only in the context of the full-length configuration. Covasphere-binding analyses demonstrate IgI/IgI interactions, but no interaction between IgII and any other domain, consistent with the biological activities that each domain mediates. The data suggest that LAMP may serve as a bifunctional guidance molecule, with distinct structural domains contributing to the promotion and inhibition of neurite outgrowth.

Animals↗

Accumulation of autophagic vacuoles and cardiomyopathy in LAMP-2-deficient mice.

Lysosome-associated membrane protein-2 (LAMP-2) is a highly glycosylated protein and an important constituent of the lysosomal membrane. Here we show that LAMP-2 deficiency in mice increases mortality between 20 and 40 days of age. The surviving mice are fertile and have an almost normal life span. Ultrastructurally, there is extensive accumulation of autophagic vacuoles in many tissues including liver, pancreas, spleen, kidney and skeletal and heart muscle. In hepatocytes, the autophagic degradation of long-lived proteins is severely impaired. Cardiac myocytes are ultrastructurally abnormal and heart contractility is severely reduced. These findings indicate that LAMP-2 is critical for autophagy. This theory is further substantiated by the finding that human LAMP-2 deficiency causing Danon's disease is associated with the accumulation of autophagic material in striated myocytes.

Amino Acids↗

Personal protection against mosquitoes in Dar es Salaam, Tanzania, by using a kerosene oil lamp to vaporize transfluthrin.

The effectiveness of a cheap and easy method of household protection against Culex quinquefasciatus Say and other mosquitoes (Diptera: Culicidae) was investigated in Dar es Salaam, Tanzania. Kerosene-burning lamps (korobois) were modified to heat and vaporize transfluthrin, a volatile pyrethroid insecticide. When transfluthrin was added to fuel of the lamp, protection against biting was poor unless a very high concentration of insecticide was used. A modified lamp (= vaporizing koroboi) was designed to overcome this problem by mixing the insecticide with vegetable oil and heating it to 120 degrees C in a tin held just above the flame. The concentration of 0.1% transfluthrin in vegetable oil gave 50-75% reduction in biting, a similar degree of protection to that obtained from burning a mosquito coil containing a synthetic pyrethroid (0.25% d-allethrin) and significantly better protection than a locally bought coil (brand 'White Crane', probably containing DDT). Greater protection (consistently > 90%) was achieved with a higher concentration of transfluthrin (0.5%) in the vegetable oil. This modified lamp is simple, cheap and employs locally available technology. With further development, and due regard to inhalation toxicity of the vaporized materials, it may offer a more cost-effective alternative to a mosquito coil as a means of personal protection, and a useful complement to a net for the early part of the evening before bedtime.

Animals↗

Effect of the spectral range of a UV lamp on the production of cyclobutane pyrimidine dimers in human skin in situ.

BACKGROUND: Ultraviolet (UV) irradiation has a broad spectrum of biological effects and a capacity to initiate skin carcinogenesis through DNA damage. The effect of different wave bands of UV light on the production of DNA damage in human skin in situ was studied with a broadband UV-B lamp TL-12 and a narrowband UV-B lamp TL-01. METHODS: Eight psoriasis patients participated in the study. Their minimal erythema dose was assessed separately for the two UV-B wave band ranges. Test areas of buttock skin were irradiated with the two spectrally differing lamps using erythemally equivalent UV doses of 40 and 80 mJ/cm2 CIE (Commission International de I'Eclairage). Punch biopsies were taken from the irradiated areas, and UV-induced DNA lesions (cyclobutane pyrimidine dimers, CPDs) in the skin were analyzed with a 32P high-performance liquid chromatography postlabelling method. RESULTS: No UV source-dependent differences in the induced levels of CPDs were detected in this study. CONCLUSION: CPD production with broadband TL-12 and narrowband TL-01 UV-B lamps in situ did not differ when erythemally equivalent UV doses were used. The preliminary result needs to be confirmed in a larger study.

Adult↗

LOCS III examination at the slit lamp, do settings matter?

PURPOSE: To explore whether slit lamp settings may influence measurements made with the LOCS III grading system. The following were tested using a total of 221 subjects: 1. Test-retest variability (with and without the neutral density filter). 2. Readings with and then without the neutral density filter. 3. Readings with maximum and minimum illumination (filter and rheostat). 4. Examinations with different slit beam width. 5. Light output from 10 slit lamps (Haag-Streit 900BM) was measured using a lightmeter. RESULTS: The 95% limits of agreement (test-retest examination) for nuclear opacity (NO), nuclear colour (NC), cortical opacity (C), and posterior subcapsular lens opacity (P) were 0.66, 0.60, 0.62 and 0.39, respectively, using standard settings. Corresponding results with the neutral density filter were similar. Examinations performed with and without the neutral density filter showed that the 95% limits of agreement increased by a factor of at least 1.7 compared with test retest data (NO and NC) and 2.2 for (C and P) (p < 0.001 (f test)). Maximum vs. minimum brightness settings increased variability by a factor of at least 2.1 (NO and NC) and 3 (C and P) (p < 0.001 (f test)). Changing beam width measurements produced a significant systematic measurement bias of 0.3 for NO and 0.4 for NC (P < 0.01 (t test)), a wider beam giving a higher score. Individual slit lamps may vary by a factor of four in their light output levels for apparently identical settings. The range of illumination produced by a slit lamp is 46-fold. CONCLUSIONS: For nuclear opacity and nuclear colour measurements, changing settings between examinations increases variability without evidence of systematic bias. However, using a thicker slit beam induced a systematic bias. For cortical and posterior subcapsular lens opacity, varying the illumination had more marked effects on reproducibility without a systematic bias.

Cataract↗

Artificial lighting in poultry houses: do hens perceive the modulation of fluorescent lamps as flicker?

1. Many poultry houses are illuminated by fluorescent lamps which produce discontinuous illumination with a frequency of either 100 or 120 Hz. 2. This study investigated whether domestic fowls perceive this discontinuity as flicker by training two Leghorn hens to choose between a continuous and a discontinuous light, all other variables being identical. 3. The light-stimulus was either monochromatic with 100% sinusoidal modulation or a fluorescent lamp whose modulation frequency could be electrically adjusted. 4. Each (correct) choice for the discontinuous light was followed by a 5 Hz higher frequency, whereas an incorrect choice was followed by a 10 Hz lower frequency. 5. On the basis of this principle the animals themselves established the highest perceivable frequency of the discontinuous light, called the Critical Fusion Frequency (CFF), that they could discriminate from continuous light. 6. These frequencies typically depend on the stimulus intensity increasing with increasing intensities, until a maximum value is reached. 7. Two factors limited the magnitudes of the CFF's that were recorded: the maximum stimulus intensities produced and variability in the chicken's response ("behavioural noise"). In spite of these constraints 105 Hz was established as the maximum CFF. 8. On the basis of extrapolation it is concluded that the direct light from fluorescent lamps driven by 50 Hz alternating current is seen by the chicken as flickering. 9. The results justify large-scale comparison of behaviour and production in poultry houses that are illuminated either by low-frequency or by high-frequency fluorescent lamps.

Animals↗

Rapid and sensitive diagnosis of adenoviral keratoconjunctivitis by loop-mediated isothermal amplification (LAMP) method.

PURPOSE: To develop a new method to detect and type adenoviruses directly from conjunctival scrapings using loop-mediated isothermal amplification (LAMP) with adenovirus (ad) type specific primer. METHODS: Using primers specific for the gene of ad1, ad3, ad4, ad8, ad19 and ad37, heat denatured adenovirus DNA was amplified by the LAMP and polymerase chain reaction (PCR). Alkaline lysed adenovirus prototype and conjunctival scrapings were also used directly as templates. RESULTS: Type specific primers amplified ad genes of the corresponding ad prototype specifically. The specific amplification was observed in both heat denatured and alkaline lysed samples. The amplified product was first detected within 45 min. Ad genotypes of clinical samples determined by the LAMP method were almost identical to those determined using the PCR-sequencing method. CONCLUSIONS: LAMP based isothermal amplification of adenovirus genome for detection and typing of adenoviruses is faster than PCR based methods. This new method will be useful for rapid diagnosis and typing of adenoviral conjunctivitis.

Adenovirus Infections, Human↗

Rapid and sensitive diagnosis of adenoviral keratoconjunctivitis by loop-mediated isothermal amplification (LAMP) method.

PURPOSE: To develop a new method to detect and type adenoviruses directly from conjunctival scrapings using loop-mediated isothermal amplification (LAMP) with adenovirus (ad) type specific primer. METHODS: Using primers specific for the gene of ad1, ad3, ad4, ad8, ad19 and ad37, heat denatured adenovirus DNA was amplified by the LAMP and polymerase chain reaction (PCR). Alkaline lysed adenovirus prototype and conjunctival scrapings were also used directly as templates. RESULTS: Type specific primers amplified ad genes of the corresponding ad prototype specifically. The specific amplification was observed in both heat denatured and alkaline lysed samples. The amplified product was first detected within 45 min. Ad genotypes of clinical samples determined by the LAMP method were almost identical to those determined using the PCR-sequencing method. CONCLUSIONS: LAMP based isothermal amplification of adenovirus genome for detection and typing of adenoviruses is faster than PCR based methods. This new method will be useful for rapid diagnosis and typing of adenoviral conjunctivitis.

Adenovirus Infections, Human↗

A novel class of autoantigens of anti-neutrophil cytoplasmic antibodies in necrotizing and crescentic glomerulonephritis: the lysosomal membrane glycoprotein h-lamp-2 in neutrophil granulocytes and a related membrane protein in glomerular endothelial cells.

Necrotizing and crescentic glomerulonephritis (NCGN) is frequently associated with circulating antineutrophil cytoplasmic autoantibodies (ANCA). It is established that ANCA are specific for soluble enzymes of granules of polymorphonuclear neutrophil granulocytes (PMN), such as myeloperoxidase (MPO) or protease 3 (PR3). The purpose of this study was to identify membrane proteins of PMNs, and/or glomerular cells, as additional autoantigenic ANCA targets. When membrane protein fractions were prepared from PMNs and isolated human glomeruli, and immunoblotted with ANCA sera of NCGN patients, two bands with apparent molecular masses of 170 and 80-110 kD (gp170/80-110) were labeled in PMNs, and a 130-kD glycoprotein (gp130) in glomeruli. Gp130 was purified, and monoclonal and rabbit antibodies (Abs) were produced which showed the same double specificity as the patient's ANCA. Using these probes, evidence was provided that gp170/80-110 is identical with human lysosomal-associated membrane protein 2 (h-lamp-2), because both proteins were immunologically cross-reactive and screening of a cDNA expression library from human promyelocytic leukemia cells with anti-gp130 Ab yielded a clone derived from h-lamp-2. Gp170/80-110 was localized primarily in granule membranes of resting PMNs, and was translocated to the cell surfaces by activation with FMLP. By contrast, gp130 was localized in the surface membranes of endothelial cells of human glomerular and renal interstitial capillaries, rather than in lysosomes, as found for h-lamp-2. Potential clinical relevance of autoantibodies to gp170/80-110 and gp130 was assessed in a preliminary trial, in which ANCA sera of patients (n = 16) with NCGN were probed with purified or recombinant antigens. Specific reactivity was detected in approximately 90% of cases with active phases of NCGN, and frequently also in combination with autoantibodies specific for PR3 or MPO. Collectively, these data provide evidence that h-lamp-2 in PMNs and a different, structurally related 130-kD membrane protein on the cell surface of renal microvascular endothelial cells are autoantigenic targets for ANCA in patients with active NCGN.

Amino Acid Sequence↗

Role of LAMP-2 in lysosome biogenesis and autophagy.

In LAMP-2-deficient mice autophagic vacuoles accumulate in many tissues, including liver, pancreas, muscle, and heart. Here we extend the phenotype analysis using cultured hepatocytes. In LAMP-2-deficient hepatocytes the half-life of both early and late autophagic vacuoles was prolonged as evaluated by quantitative electron microscopy. However, an endocytic tracer reached the autophagic vacuoles, indicating delivery of endo/lysosomal constituents to autophagic vacuoles. Enzyme activity measurements showed that the trafficking of some lysosomal enzymes to lysosomes was impaired. Immunoprecipitation of metabolically labeled cathepsin D indicated reduced intracellular retention and processing in the knockout cells. The steady-state level of 300-kDa mannose 6-phosphate receptor was slightly lower in LAMP-2-deficient hepatocytes, whereas that of 46-kDa mannose 6-phosphate receptor was decreased to 30% of controls due to a shorter half-life. Less receptor was found in the Golgi region and in vesicles and tubules surrounding multivesicular endosomes, suggesting impaired recycling from endosomes to the Golgi. More receptor was found in autophagic vacuoles, which may explain its shorter half-life. Our data indicate that in hepatocytes LAMP-2 deficiency either directly or indirectly leads to impaired recycling of 46-kDa mannose 6-phosphate receptors and partial mistargeting of a subset of lysosomal enzymes. Autophagic vacuoles may accumulate due to impaired capacity for lysosomal degradation.

Animals↗

Potent genotoxicity of halogen lamps, compared to fluorescent light and sunlight.

The light emitted by halogen lamps induced mutations in Salmonella typhimurium and DNA damage in Escherichia coli, as shown by the hypersensitivity of DNA repair-deficient strains. The mutagenicity of halogen lamps was considerably higher than that of fluorescent light and of sunlight, even at much lower illuminance levels. Excision mechanisms and SOS functions were involved in repairing light-induced base-pair substitutions and frameshift errors in bacterial DNA. At variance with solar irradiation, which produces mutagenic effects over a wide UV spectrum, genotoxicity of halogen lamps was almost exclusively due to far-UV wavelengths transmissible through UV-R-250 and UV-R-280 interference filters. The main mutagenic component of fluorescent light (254 nm) were almost 10(4)-fold more mutagenic than near-UV wavelengths (365 nm). All light sources exhibited some residual mutagenicity even following filtration through various cloths. On the other hand, appropriate glass or plastic covers consistently prevented mutagenic effects. This emphasizes the urgent need for a compulsory shielding of halogen and fluorescent lamps in order to prevent unnecessary exposures to genotoxic and potentially carcinogenic UV radiations.

DNA Damage↗

Comparison of the 308-nm excimer laser and a 308-nm excimer lamp with 311-nm narrowband ultraviolet B in the treatment of psoriasis.

BACKGROUND: Psoriasis is a chronic, genetically determined inflammatory disease, characterized by an immunomediated pathogenesis, which affects approximately 1-3% of the population. Various modalities have been used for psoriasis treatment, including ultraviolet (UV) radiation. Narrowband UVB (311 nm) phototherapy is a well-established, widely used and highly efficient treatment for psoriasis, but a big disadvantage is that large areas of unaffected skin are irradiated along with the psoriatic lesions. OBJECTIVES: This investigation evaluates a 308-nm excimer laser and a 308-nm excimer lamp in comparison with 311-nm narrowband UVB in the treatment of patch psoriasis by using two different dose-increase schemes. MATERIALS AND METHODS: Fifteen patients with plaque psoriasis were enrolled in the study (first regime). Three different psoriatic lesions were treated with the 308-nm excimer laser, the 308-nm excimer lamp or 311-nm narrowband UVB three times per week. UVB doses were increased slowly and stepwise (1, 1, 2, 2, 3, 3, ...multiple MEDs). Sixteen patients were enrolled in the second regime. Two plaques were treated with the 308-nm excimer laser or with the 308-nm lamp with an accelerated scheme (2, 2, 4, 4, 6, 6, ...multiple MEDs) three times per week. We increased the UVB doses every second treatment (first and second regime) during the whole treatment. If blistering occurred, the blistered plaque was not treated on the next scheduled treatment. At every third visit and 1, 2 and 4 months after the last treatment a Psoriasis Severity Index (PSI) score was assigned in both regimes. RESULTS: Using Friedman analysis, the PSI scores did not show a statistically significant difference (P > 0.05) comparing 308-nm laser therapy, 308-nm lamp therapy and 311-nm narrowband therapy after 10 weeks in the first regime. The mean number of treatments to achieve clearance was 24. With the accelerated scheme, clearance could be achieved with fewer treatments and with half the cumulative dose of the first regime. Nevertheless, the side-effects such as blistering and crusting were also increased. CONCLUSIONS: Both 308-nm light sources can clear patch psoriasis in a similar manner to standard phototherapy, with the advantage of the ability to treat exclusively the affected skin and with a reduced cumulative dose, thus perhaps reducing the long-term risk of carcinogenicity.

Adult↗

Opsonized virulent Brucella abortus replicates within nonacidic, endoplasmic reticulum-negative, LAMP-1-positive phagosomes in human monocytes.

Cells in the Brucella spp. are intracellular pathogens that survive and replicate within host monocytes. Brucella maintains persistent infections in animals despite the production of high levels of anti-Brucella-specific antibodies. To determine the effect of antibody opsonization on the ability of Brucella to establish itself within monocytes, the intracellular trafficking of virulent Brucella abortus 2308 and attenuated hfq and bacA mutants was followed in the human monocytic cell line THP-1. Early trafficking events of B. abortus 2308-containing phagosomes (BCP) were indistinguishable from those seen for control particles (heat-killed B. abortus 2308, live Escherichia coli HB101, or latex beads). All phagosomes transiently communicated the early-endosomal compartment and rapidly matured into LAMP-1(+), cathepsin D(+), and acidic phagosomes. By 2 h postinfection, however, the number of cathepsin D(+) BCP was significantly lower for live B. abortus 2308-infected cells than for either Brucella mutant strains or control particles. B. abortus 2308 persisted within these cathepsin D(-), LAMP-1(+), and acidic vesicles; however, at the onset of intracellular replication, the numbers of acidic B. abortus 2308 BCP decreased while remaining cathepsin D(-) and LAMP-1(+). In contrast to B. abortus 2308, the isogenic hfq and bacA mutants remained in acidic, LAMP-1(+) phagosomes and failed to initiate intracellular replication. Notably, markers specific for the host endoplasmic reticulum were absent from the BCPs throughout the course of the infection. Thus, opsonized B. abortus in human monocytes survives within phagosomes that remain in the endosomal pathway and replication of virulent B. abortus 2308 within these vesicles corresponds with an increase in intraphagosomal pH.

Antibodies, Bacterial↗

Depth measurement with the slit-lamp microscope.

The sagittal distance of ocular structures can be obtained with a slit-lamp microscope providing the movement of the slit-lamp can be measured. A simple device consisting of a pointer attached by a spring clip to the axle of a Haag-Streit 900 slit-lamp is described. The pointer rides over a scale which slides with the slit-lamp. Comparisons of anterior chamber depth and lens thickness showed a high correlation between this optical method and ultrasound measurements.

Anterior Chamber↗

Automated, real time extraction of fundus images from slit lamp fundus biomicroscope video image sequences.

AIMS: Slit lamp fundus biomicroscopy allows for high magnification, stereoscopic diagnosis, and treatment of macular diseases. Variable contrast, narrow field of view, and specular reflections arising from the cornea, sclera, and examining lens reduce image quality; these images are of limited clinical utility for diagnosis, treatment planning, and photodocumentation when compared with fundus camera images. Algorithms are being developed to segment fundus imagery from slit lamp biomicroscopic video image sequences in order to improve clinical utility. METHODS: Video fundus image sequences of human volunteers were acquired with a video equipped, Nikon NS-1V slit lamp biomicroscope. Custom developed software identified specular reflections based on brightness and colour content, and extracted the illuminated fundus image based on colour image analysis and size constraints. RESULTS: In five subjects with variable image quality, the approach allowed for automatic, robust, accurate extraction of that portion of the video image corresponding to the illuminated portion of the fundus. Non-real time analysis allowed for fundus image segmentation for each frame of the image sequence. In real time, segmentation occurs at 2 Hz, and improvements are being implemented for video rate performance. CONCLUSIONS: Computer vision algorithms allow for real time extraction of fundus imagery from marginal quality, slit lamp fundus biomicroscope image sequences.

Algorithms↗

Utilization of the indirect lysosome targeting pathway by lysosome-associated membrane proteins (LAMPs) is influenced largely by the C-terminal residue of their GYXXphi targeting signals.

A systematic study was conducted on the requirements at the C-terminal position for the targeting of LAMPs to lysosomes, examining the hypothesis that a bulky hydrophobic residue is required. Mutations deleting or replacing the C-terminal valine with G, A, C, L, I, M, K, F, Y, or W were constructed in a reporter protein consisting of the lumenal/extracellular domain of avian LAMP-1 fused to the transmembrane and cytoplasmic domains of LAMP-2b. The steady-state distribution of each mutant form in mouse L-cells was assessed by quantitative antibody binding assays and immunofluorescence microscopy; efficiency of internalization from the plasma membrane and delivery to the lysosome were also estimated. It is found that (a) only C-terminal V, L, I, M, and F mediated efficient targeting to lysosomes, demonstrating the importance hydrophobicity and an optimal size of the C-terminal residue in targeting; (b) efficiency of lysosomal targeting generally correlated with efficiency of internalization; and (c) mutant forms that did not target well to lysosomes showed unique distributions in cells rather than simply default accumulation in the plasma membrane. Interactions of the targeting signals with adaptor subunits were measured using a yeast two-hybrid assay. The results are consistent with the hypothesis that trafficking of LAMP forms in cells through the indirect pathway is determined by the affinities of their targeting signals, predominantly for the mu2 and mu3 adaptors involved at plasma membrane and endosomal cellular sorting sites, respectively.

Amino Acid Sequence↗