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At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Adjusting the slit-lamp oculars: an unnecessary burden or a must?

Adjusting the slit-lamp eyepiece rings is perceived by some to be insignificant for achieving adequate focus. Others assume that these rings should be set only to compensate for one's refractive error. Observations are presented concerning the eyepiece scale setting during routine examinations, slit-lamp mounted YAG and Argon laser procedures and during opthalmic surgery. Diagrams illustrate the optical basis of these observations. Factors influencing optimal eyepiece ring setting, besides ametropia, include slit-lamp misalignment (variations in calibration) as well as unconscious accommodation. An inaccurate setting cannot be fully compensated by adjusting the slit-lamp joy-stick. When an incorrect setting is used, while using oblique illumination, it becomes impossible to focus on details placed at the center of the viewfinder. In addition, irrespective of joy-stick position, it is impossible to view an oblique slit transecting the cornea in perfect focus. An accurate setting, as a whole, results in sharper images throughout the slit-lamp examination. Differences between individual instruments make it necessary to reset the eyepieces for each eye and for each individual instrument. Methods are described for evaluating the need for readjustment, as well as a simple technique for calibration in the absence of a focusing rod.

Calibration↗
PubMedDate not supplied

On focusing the slit-lamp: Part I. An inaccurate ocular setting--what is there to lose?

Adjustments of the diopter rings on the slit-lamp oculars compensate for three independent factors: the observer's refractive error, the observer's state of accommodation, and any instrument misalignment. An inaccurate setting of these rings will significantly affect the slit-lamp image quality, as well as the precision and accuracy of slit-lamp mounted lasers, such as are used for retinal photocoagulation, YAG capsulotomy, and laser trabeculoplasty. For each slit-lamp and microscope-related examination technique, photographic technique, and laser procedure, the consequences of an incorrect ocular setting are discussed. Data are presented on the preferred ocular settings of several random observers, highlighting both interobserver and intraobserver variability. Finally, photographs demonstrate the image deterioration that occurs when an incorrect ocular setting is used. It is shown that for younger observers, one's distance refraction is only seldom the correct setting of the slit-lamp oculars, and that on different instruments, one should not be surprised to find somewhat different settings. Examiners are urged to check the accuracy of their habitual setting, if only to find out whether the improvement in image quality is worth the extra bother.

Calibration↗
PubMed2003

Assessment of the acute pulmonary toxicity of lamp oil aspiration in the isolated perfused rat lung.

Mainly among children incidental ingestion of conventional lamp oils (paraffin oil) is responsible for casual intoxications with severe pulmonary toxicity and fatal consequences. On the basis of the isolated blood-free perfused rat lung we developed a model to study the acute toxic effects of lamp oil. Three oils were studied: conventional paraffin lamp oil (kinematic viscosity 1.62 10(-6) m(2)/sec), the methyl ester Edenor ME C12 70 (2.7 10(-6) m(2)/s) and another ester Edenor LPL (4.5 10(-6) m(2)/s). The oils were instilled into the trachea of isolated rat lungs and the changes in lung mechanics (tidal volume, pulmonary compliance and pulmonary conductance) as well as edema formation (increase in lung weight) studied. Instillation of as little as 10 microl paraffin oil caused complete failure of lung functions within 20 min and even 2 microl caused noticeable edema. Similar results were obtained with Edenor ME C12 70, which appeared to be even more toxic than paraffin oil, while Edenor LPL was less toxic. We conclude that tracheal instillation of oils into isolated perfused rat lungs may be a useful model to study the toxicity of lamp oils in vitro. Our findings further suggest that Edenor LPL may be a safer alternative for use as a lamp oil than paraffin oil.

Acute Disease↗
PubMed1998

A novel lysosome-associated membrane glycoprotein, DC-LAMP, induced upon DC maturation, is transiently expressed in MHC class II compartment.

We have identified a novel lysosome-associated membrane glycoprotein localized on chromosome 3q26.3-q27, DC-LAMP, which is homologous to CD68. DC-LAMP mRNA is present only in lymphoid organs and DC. A specific MAb detects the protein exclusively in interdigitating dendritic cells. Expression of DC-LAMP increases progressively during in vitro DC differentiation, but sharply upon activation with LPS, TNFalpha, or CD40L. Confocal microscopy confirmed the lysosomal distribution of the protein. Furthermore, DC-LAMP was found in the MHC class II compartment immediately before the translocation of MHC class II molecules to the cell surface, after which it concentrates into perinuclear lysosomes. This suggests that DC-LAMP might change the lysosome function after the transfer of peptide-MHC class II molecules to the surface of DC.

Amino Acid Sequence↗
PubMed2000

[Slit-lamp perimetry: a new diagnostic technique].

AIM OF THE STUDY: To test a novel diagnostic technique, slit-lamp perimetry. PATIENTS AND METHODS: Slit-lamp perimetry is performed during a normal slit-lamp examination by projecting a small, round light mark onto the fundus. The light mark is moved and consecutively the patient is asked, if the light moved towards or away from the scotoma. Using the patients feedback the light mark can be placed exactly onto the retinal region corresponding to the scotoma. This method was tested on a patient with a microinfarction of a small retinal arteriole and on two patients with small preretinal parapapillary vitreous floaters. RESULTS: Slit-lamp perimetry correctly localized preretinal vitreous floaters and a fresh cotton wool spot missed on an dilated fundus examination. CONCLUSION: Slit-lamp perimetry is a novel rapid diagnostic technique to localize retinal and preretinal pathologies reponsibles for scotomas.

Adult↗
PubMed2005

Phenotypic heterogeneity in two unrelated Danon patients associated with the same LAMP-2 gene mutation.

Danon disease, an X-linked cardioskeletal myopathy caused by primary deficiency of lysosome-associated membrane protein-2 (LAMP-2), is clinically characterized by cardiomyopathy, myopathy, and variable mental retardation. The pathological hallmark of the disease is the absence of LAMP-2 immunohistochemical staining in muscle. The LAMP-2 gene mutations reported thus far are generally private mutations. We describe two cases of Danon disease with different clinical presentation, in whom we identified the same exon skipping mutation c.928G>A in the LAMP-2 gene. The first patient was affected by an early onset myopathy and hypertrophic cardiomyopathy (HCM) that partially improved with drug treatment. A first muscle biopsy at age 4 months showed markedly increased glycogen, and acid maltase deficiency was ruled out biochemically. A second muscle biopsy, performed at age 3(1/2) years, showed very mild abnormalities. The second child at age 15 years had mild, diffuse muscle weakness and wasting, moderate mental deficiency, and HCM. Two serial biopsies performed at age 8 and 15 years showed similar findings of multiple esterase-positive vacuoles in type I myofibers. In both patients the immunohistochemical study demonstrated the absence of LAMP-2 in skeletal muscle.

Adolescent↗
PubMed2006

Filtering bleb evaluation with slit-lamp-adapted 1310-nm optical coherence tomography.

PURPOSE: Investigation of slit-lamp-adapted 1310-nm optical coherence tomography (OCT) as an in vivo imaging device in the postoperative course of glaucoma surgery. METHODS: Postoperative images of filtering blebs and deep sclerectomies and their healing processes were qualitatively evaluated with a slit-lamp-adapted anterior segment OCT (AS-OCT; Heidelberg Engineering, Heidelberg, Germany) in 28 patients. Ophthalmologic examinations included slit-lamp examination, applanation tonometry, and slit-lamp photography. The OCT scans were qualitatively correlated with the morphologic and functional outcome of the filtering bleb. RESULTS: 1310-nm OCT was able to demonstrate the internal structure and the dimensions of filtering blebs, as well as the scleral flap and the deep sclerectomy location including Descemet membrane. Functioning filtering blebs showed a low OCT signal, small fluid-filled cysts, superficial microcystic layer, and a slack internal texture. High internal reflectivity indicated an earlier scarring of the filtering bleb. Nonfunctioning filtering blebs delivered a high OCT signal, no or few cysts, and a dense internal texture. These different OCT patterns correlated with the clinical outcome. CONCLUSIONS: Slit-lamp-adapted 1310-nm OCT allowed the noncontact observation and documentation of the postoperative healing course of filtering blebs after glaucoma surgery. Internal structures of the filtering bleb and deep sclerectomies could be visualized. Functioning and dysfunctioning filtering blebs delivered different OCT pattern and correlated with the clinical outcome. This could be a new way to assess the postoperative healing process with the possibility of earlier intervention in cases of impending scarring.

Blister↗
PubMed1993

Visual safety of quartz linear lamps.

A quartz linear lamp (QLL) is a compact infra-red (i.r.) heating lamp. It consists of a tungsten filament in a quartz envelope, which for space heating purposes is surrounded by a ruby coloured filter. The filament runs at about 2400 K and produces i.r. radiation with a peak output at 1200 nm. The lamps are widely used for space heating and are normally fitted with a parabolic reflector. There are no statutory criteria for potential visual hazards resulting from the use of such lamps in the U.K. The ACGIH has produced a provisional set of rules on light and near i.r. This paper reviews potential hazards to the eye in the context of the ACGIH rules and the output of QLL heaters. The heaters produce no u.v. or blue light hazards. The brightness and heat of the lamp is sufficient to produce an aversion response which will prevent retinal thermal damage from inadvertent viewing. The probability of retinal thermal injury from an i.r.-A image focused on the retina is examined and it is shown that there is no risk at normal viewing distances. To prevent any risk of cataractogenesis, the rules provide for an upper limit of irradiance (TLV) at the eye of 100 W m-2 in the i.r.-A band; the paper examines the potential hazard from longer wavelengths and concludes that they do not present a hazard with this type of heating. The conclusion is that QLL heaters used for space heating in accordance with manufacturer's instructions present no hazard to the eye.

Eye↗
PubMed1999

Induction and prevention of micronuclei and chromosomal aberrations in cultured human lymphocytes exposed to the light of halogen tungsten lamps.

Previous studies have shown that the light emitted by halogen tungsten lamps contains UV radiation in the UV-A, UV-B and UV-C regions, induces mutations and irreparable DNA damage in bacteria, enhances the frequency of micronuclei in cultured human lymphocytes and is potently carcinogenic to the skin of hairless mice. The present study showed that the light emitted by an uncovered, traditional halogen lamp induces a significant, dose-related and time-related increase not only in micronuclei but also in chromosome-type aberrations, such as breaks, and even more in chromatid-type aberrations, such as isochromatid breaks, exchanges and isochromatid/chromatid interchanges, all including gaps or not, in cultured human lymphocytes. All these genotoxic effects were completely prevented by shielding the same lamp with a silica glass cover, blocking UV radiation. A new model of halogen lamp, having the quartz bulb treated in order to reduce the output of UV radiation, was considerably less genotoxic than the uncovered halogen lamp, yet induction of chromosomal alterations was observed at high illuminance levels.

Adult↗
PubMed2006

Compact fluorescent lamp phosphors in accidental radiation monitoring.

The application of lamp phosphors for accidental dosimetry is a new concept. Since the materials used in fluorescent lamps are good photo luminescent materials, if one can either use the inherent defects present in the phosphor or add suitable modifiers to induce thermoluminescence (TL) in these phosphors, then the device (fluorescent lamp) can be used as an accidental dosemeter. In continuation of our search for a suitable phosphor material, which can serve both as an efficient lamp phosphor and as a good radiation monitoring device, detailed examination has been carried out on cerium and terbium-doped lanthanum phosphate material. A (90)Sr beta source with 50 mCi strength (1.85 GBq) was used as the irradiation source for TL studies. The TL response as a function of dose received was examined for all phosphors used and it was observed that the intensity of the TL peak vs. dose received was a linear function in the dose range 0.1-200 Gy in each case. Incidentally LaPO(4): Ce,Tb is a component of the compact fluorescent lamp marketed recently as an energy bright light source. Besides having very good luminescence efficiency, good dosimetric properties of these phosphors render them useful for their use in accidental dosimetry also.

Beta Particles↗
PubMed1993

Lysosome-associated membrane protein-1 (LAMP-1) is the melanocyte vesicular membrane glycoprotein band II.

Coated vesicles play a critical role in the process of melanogenesis. Antisera raised against a coated vesicle fraction from mouse melanoma cells recognize two major glycoprotein antigens, band I (47-55 kd) and band II (90-120 kd). We demonstrate that band II is lysosome-associated membrane protein 1 (LAMP-1) by the following criteria: 1) the molecular weight and abundance of LAMP-1 varies among tissues but is always identical to that of band II; 2) band II and LAMP-1 co-migrate in sucrose gradient sedimentation studies; 3) immunodepletion of cell extracts with antivesicle serum removes all LAMP-1; and 4) intact organelles immunoisolated with antivesicle serum contain band II and LAMP-1. Our results further confirm the long-suspected relationship between melanosomes and the lysosomal lineage of organelles.

Animals↗
PubMed1994

Coordinated mRNA and protein expression of human LAMP-1 in induction of melanogenesis after UV-B exposure and co-transfection of human tyrosinase and TRP-1 cDNAs.

In order to better understand the cascade of melanogenic events in melanocytes, this report has introduced our two recent approaches for the expression of melanogenesis/or melanosome-associated genes and encoded proteins in melanocytes (melanoma cells) after repeated exposure to UV-B and after cotransfection of two human genes, i.e., tyrosinase and tyrosinase-related protein-1 (TRP-1). Repeated exposure of UV-B (2.5-5.0 mJ/cm2) caused not only upregulation of tyrosinase and TRP-1 genes but also coordinated increase in the gene and protein synthesis expression of Lamp-1 (lysosome-associated membrane protein-1). When COS-7 kidney cells and amelanotic melanoma (C32 and SK-MEL-24) and melanotic melanoma (G361 and SK-MEL-23) cells were exposed to cotransfection of human tyrosinase and TRP-1 cDNAs, there was also an increased expression of Lamp-1 mRNA and protein along with tyrosinase activation and new melanin synthesis. Importantly, single transfectants of human tyrosinase cDNA revealed marked cellular degeneration, whereas this degeneration was not seen in single transfectants of TRP-1 cDNA or cotransfectants of human tyrosinase and TRP-1 cDNAs, indicating that TRP-1 prevented, along with Lamp-1, programmed death of melanocytes after transfection of tyrosinase gene. The coordinated expression of TRP-1 and Lamp-1 was further confirmed by antisense oligodeoxynucleotide hybridization experiment against Lamp-1 gene, showing the decreased expression of TRP-1 as identified by three different types of anti-TRP-1 monoclonal antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMedDate not supplied

A comparison of erythema efficacy of ultraviolet B irradiation from Philips TL12 and TL01 lamps.

The erythema efficacy of UVB irradiation from Philips TL12 and TL01 lamps has been evaluated and compared. Thirty-seven healthy Thai volunteers were irradiated on the previously unexposed lower back with TL12 and TL01 lamps in doses ranging 100 to 550 mJ/cm2 and 360 to 2020 mJ/cm2, respectively. Erythema was evaluated clinically and measured by a narrow-band spectrophotometer before exposure and 24 h after exposure. The threshold doses of UVB that induced barely perceptible erythema (MEDb) with well-defined border erythema (MEDw) and the steepness of the dose-response curves for erythema (DRAE) were compared. We found that MEDb and MEDw of the TL01 lamps were 4.19 and 4.52 times those of TL12 lamps, which were similar to those calculated from the CIE erythema action spectrum (4.2). However, the DRAE of the two lamps were quite similar. Because the initial dosage of UVB phototherapy is usually given as a percentage of a patient's MED, the initial exposure of TL01-UVB phototherapy should be about 4.2 times that of TL12-UVB.

Adolescent↗
PubMed1993

General purpose lamps induce polyoma DNA replication in H3 cells.

We have previously demonstrated the ability of UVC (254 nm) radiation to induce asynchronous polyoma replication in rat fibroblast cells (H3 line) that contain an integrated copy of polyoma virus. In the present study we show that general purpose lamps can induce polyoma replication in these cells as well. The amount of UV radiation emitted by three different light sources was determined and the effects of each source on the replication of polyoma DNA was assessed. Our findings indicate that a 100 W incandescent lamp had a minimal effect on replication, whereas a 90 s exposure to a halogen lamp or a 160 W mercury vapor lamp induced replication 1.5-fold and 2-fold, respectively, in comparison with nontreated controls. We have previously shown that asynchronous polyoma replication in H3 cells involves UV-inducible cellular protein factors. Our present results indicate that these factors are also activated by exposure to commonly used lamps that emit comparable doses of UV radiation.

Animals↗
PubMed1984

Photometric oculometry. I. An analysis of the optical principles in slit-lamp fluorophotometry.

The optical principles of slit-lamp fluorophotometry are analysed by aid of a mathematical model of the optical system. The analysis forms the theoretical basis for a slit-lamp technique called photometric oculometry, which makes possible an estimation of intraocular axial distances and axial length. The technique is based on a calculation--by aid of a mathematical model of the eye--of the ratio between intraocular movement of the slit-lamp focal plane and corresponding movement of the slit-lamp. Intraocular axial distances can be calculated by aid of this ratio and a direct measurement of the slit-lamp movement when the focal plane is moved in the optical axis from retina to cornea. These items are prerequisites for a quantitative determination of the blood-retinal barrier permeability to fluorescein during vitreous fluorophotometry.

Eye↗
PubMed2001

Mosaicking and enhancement of slit lamp biomicroscopic fundus images.

AIMS: To process video slit lamp biomicroscopic fundus image sequences in order to generate wide field, high quality fundus image montages which might be suitable for photodocumentation. METHODS: Slit lamp biomicroscopic fundus examination was performed on human volunteers with a contact or non-contact lens. A stock, charge coupled device camera permitted image capture and storage of the image sequence at 30 frames per second. Acquisition time was approximately 30 seconds. Individual slit lamp biomicroscope fundus image frames were aligned and blended with custom developed software. RESULTS: The developed algorithms allowed for highly accurate alignment and blending of partially overlapping slit lamp biomicroscopic fundus images to generate a seamless, high quality, wide field montage. CONCLUSIONS: Video image acquisition and processing algorithms allow for mosaicking and enhancement of slit lamp biomicroscopic fundus images. The improved quality and wide field of view may confer suitability for inexpensive, real time photodocumentation of disc and macular abnormalities.

Algorithms↗
PubMed2004

[Principle of LAMP method--a simple and rapid gene amplification method].

So far nucleic acid test (NAT) has been employed in various fields, including infectious disease diagnoses. However, due to its complicated procedures and relatively high cost, it has not been widely utilized in many actual diagnostic applications. We have therefore developed a simple and rapid gene amplification technology, Loop-mediated Isothermal Amplification (LAMP) method, which has shown prominent results of surpassing the performance of the conventional gene amplification methods. LAMP method acquires three main features: (1) all reaction can be carried out under isothermal conditions; (2) the amplification efficiency is extremely high and tremendous amount of amplification products can be obtained; and (3) the reaction is highly specific. Furthermore, developed from the standard LAMP method, a rapid LAMP method, by adding in the loop primers, can reduce the amplification time from the previous 1 hour to less than 30 minutes. Enormous amount of white precipitate of magnesium pyrophosphate is produced as a by-product of the amplification, therefore, direct visual detection is possible without using any reaction indicators and detection equipments. We believe LAMP technology, with the integration of these features, can rightly apply to clinical genetic testing, food and environmental analysis, as well as NAT in different fields.

Chemical Precipitation↗
PubMed1999

Conversion of lens slit lamp photographs into physical light-scattering units.

PURPOSE: To derive from lens slit lamp photographs by means of densitometry the physically defined quantity for light scattering (the Rayleigh ratio) and to expand the use of the Lens Opacity Classification System (LOCS III) to include clear lenses and also to calibrate the LOCS III Nuclear Opacity (NO) score in physical terms. METHODS: Series of slit lamp photographs were taken from 38 eyes from 29 subjects (age range 18 to 84 years old) including cataracts, for 0.1- and 0.2-mm slit width, using 200 ASA and 1600 ASA film speed (Kodak professional; Eastman Kodak, Rochester, NY) and different flash settings with a Topcon SL-6E (12 slit/speed/flash combinations; Paramus, NJ). Additionally 19 eyes were photographed with a Zeiss 40 SL/P (8 slit/speed/flash combinations; Carl Zeiss, Thornwood, NY). A calibrated suspension of latex spheres also was photographed at the same 20 conditions. Densitometry was performed on the nuclear area of all photographs including the LOCS III standards, using a photometrically corrected photocell. Slit width and flash intensity settings were photometrically calibrated. All eyes and the suspension were digitally "photographed" with the EAS-1000 (Nidek, Gamagori, Japan) Scheimpflug system. RESULTS: For each eye and the suspension, the series of 20 or 12 densities, corresponding to a range of about 1 log unit in the amount of light used, proved to follow closely a course common to all eyes (the two film characteristics), apart from a shift in the amount of light (because of the differences in light back scattering). CONCLUSIONS: From normal slit lamp photographs, the physical quantity for light (back) scattering can be derived using transformation graphs derived in this study. The LOCS III NO score also can be used for clear lenses and translated into physical units. In this way, slit lamp photography can be used better for more precise studies, provided some minimal calibration of the photograph slit lamp.

Adolescent↗