Lissamine Green Dyes
Indocyanine Green
Dry Eye Syndromes
Dye Dilution Technique
Keratitis, Herpetic
Rhodamines
Coloring Agents
Rose Bengal
Cornea
PCR assessment of HSV-1 corneal infection in animals treated with rose bengal and lissamine green B. (1/24)
PURPOSE: In vivo, the ophthalmic dye rose bengal displays profound antiviral effects against herpes simplex virus (HSV)-1, thus limiting its utility in diagnosis of epithelial keratitis when used before viral culture is performed. In contrast, lissamine green B does not possess significant antiviral activity in vivo. To determine whether polymerase chain reaction (PCR) could successfully detect HSV-1 DNA in ocular samples that have been exposed to ophthalmic dyes, animal models were used to observe the presence of infectious HSV-1 and viral DNA in eyes treated with rose bengal or lissamine green B. METHODS: Animals were bilaterally infected with HSV-1 strain H129, and at daily intervals up to 16 days post infection (dpi) rose bengal or lissamine green B was instilled in the left eyes. The right eyes were not treated with dyes. Swabs of the dye-treated and untreated eyes were assayed by PCR for viral infectivity by culture and the presence of DNA specific for a fragment of the HSV-1 DNA polymerase gene. RESULTS: A statistically equivalent number of samples from lissamine green B-treated and untreated eyes were positive by both viral culture and PCR. In contrast, rose bengal significantly decreased the infectious virus present in ocular secretions. A total of 44% and 78% of the rose bengal-treated and untreated eye samples, respectively, were positive by culture from 1 through 16 dpi. PCR was more sensitive than culture for detection of HSV-1 in rose bengal-treated eyes, in that 74% of rose bengal-treated samples were positive by PCR compared with 44% that were positive by culture during the 16-day period studied. It was also noted that both rose bengal and lissamine green B treatments slightly prolonged the period during which viral DNA was detectable in ocular secretions by PCR, possibly because the singlet oxygen produced by these photoreactive dyes compromised ocular cellular, humoral, and nonspecific immune factors allowing viral DNA to persist for slightly longer periods. CONCLUSIONS: PCR can successfully detect HSV-1 DNA in ocular samples that are culture negative and contain rose bengal or lissamine green B. Visualization of ocular epithelial defects with lissamine green B does not interfere with detection of infectious virus or HSV-1 DNA. (+info)Tracer studies in the rat demonstrate misdirected filtration and peritubular filtrate spreading in nephrons with segmental glomerulosclerosis. (2/24)
In two genetic models of "classic" focal segmental glomerulosclerosis (FSGS), the Milan normotensive and the Fawn-hooded hypertensive rats, tracer studies were performed to test the hypothesis that misdirected glomerular filtration and peritubular filtrate spreading are relevant mechanisms that contribute to nephron degeneration in this disease. Two exogenous tracers, lissamine green and horse spleen ferritin, were administered by intravenous injection and subsequently traced histologically in serial kidney sections. In contrast to control rats, both tracers in kidneys of Milan normotensive and Fawn-hooded hypertensive rats with established FSGS were found to accumulate extracellularly at the following sites: (1) within tuft adhesions to Bowman's capsule and associated paraglomerular spaces, (2) at the glomerulotubular junction contained within extensions of the paraglomerular spaces onto the tubule, and (3) within subepithelial peritubular spaces eventually encircling the entire proximal convolution of an affected nephron. This distribution strongly suggests the existence of misdirected filtration into tuft adhesions to Bowman's capsule and subsequent spreading of the filtrate around the entire circumference of a glomerulus and, alongside the glomerulotubular junction, onto the outer aspect of the corresponding tubule. This leads to an interstitial response that consists of the formation of a barrier of sheet-like fibroblast processes around the affected nephron, which confines the filtrate spreading and, subsequently, the destructive process to the affected nephron. No evidence was found that either misdirected filtration and peritubular filtrate spreading themselves or the associated tubulo-interstitial process led to the transfer of the injury from an affected nephron to an unaffected nephron. It is concluded that in the context of FSGS development, misdirected filtration and peritubular filtrate spreading are important damaging mechanisms that underlie the extension of glomerular injury to the corresponding tubulointerstitium, thus leading finally to degeneration of both the glomerulus and the tubule of a severely injured nephron. (+info)A resonance light-scattering determination of proteins with fast green FCF. (3/24)
The interaction of Fast Green FCF (FCF) with proteins (including bovine serum albumin (BSA), human serum albumin (HSA), pepsin (Pep) and alpha-chymotrypsin (Chy), and lysozyme (Lys)) was characterized by enhanced resonance light-scattering (RLS) measurements using a common spectrofluorometer. The enhanced RLS signals of FCF by proteins at 279.0 nm were obtained, and the mechanism of the RLS enhancement was considered in terms of the effects of the pH and ionic strength on the interaction. It was found that the enhanced RLS intensities were in proportion to the concentrations of proteins in the range of nanogram levels, displaying that the present assay is much more sensitive than the reported RLS methods, with the limits of determination being 4.54, 0.6, 22.8, 4.32 and 1.75 ng/ml for BSA, HSA, Pep, Chy, and Lys. respectively. (+info)The relationship between habitual patient-reported symptoms and clinical signs among patients with dry eye of varying severity. (4/24)
PURPOSE: To investigate symptom profiles and clinical signs in subjects with dry eye and normal subjects in a cross-sectional multicenter study. METHODS: Subjects aged 35 to 65 were recruited according to dry eye diagnostic codes and telephone interview and completed the Dry Eye Questionnaire 2001, among others, and underwent dry eye clinical tests. RESULTS: Subjects (122) included 28 control subjects (C), 73 with non-Sjogren's keratoconjunctivitis sicca (non-SS KCS) and 21 with Sjogren's syndrome (SS). Subjects with SS or non-SS KCS reported discomfort and dryness most frequently and that many symptoms worsened over the day and were quite bothersome. Groups were significantly different in corneal fluorescein staining, conjunctival lissamine green staining, Schirmer 1 tear test, and tear break-up time (TBUT; chi2 and Kruskal-Wallis, P<0.0001). Statistically significant, but moderate, correlations were found between the frequency and evening intensity of dryness and discomfort and TBUT, Schirmer's tear test, overall corneal fluorescein staining, and temporal lissamine green conjunctival staining (Spearman r=0.31-0.45, P<0.01). Symptoms were moderately to highly correlated with the clinician's global grading of severity and highly correlated to patient's self-assessment of severity (r=0.46-0.86, P<0.0001), whereas signs showed lower correlations (r=0.22-0.46, P<0.0001). CONCLUSIONS: Subjects with SS or non-SS KCS reported frequent and intense ocular surface symptoms in the evening, some of which correlated moderately with clinical test results. The global clinician grade of dry eye correlated more highly with patient symptoms than did clinical signs, suggesting that patient symptoms influence dry eye diagnosis and grading of dry eye more than clinical test results. (+info)Articular cartilage fibrillation and permeability to Light Green SF dye. A method for the detection of pre-microscopic disease? (5/24)
We describe a method which may be useful for the selection of samples for the study of early fibrillation in human articular cartilage. Blocks of cartilage and bone were cut post-mortem from the medial tibial condyles of 29 male and 31 female subjects and the grade of fibrillation was assessed from sections. Contiguous, unfixed blocks of cartilage from the same surface were immersed in a solution of the dye Light Green SF. Sections of these blocks were cut and the rate of penetration of the dye measured at 30 equidistant points across the condylar surface. The relationship between the grade of fibrillation and the rate of dye diffusion was then determined. We demonstrated a significant correlation between the two variables. This technique may make it possible to detect a pre-fibrillary state in apparently normal specimens. (+info)Dissection of bidirectional synaptic plasticity into saturable unidirectional processes. (6/24)
In populations of synapses, overall synaptic strength can undergo either a net strengthening (long-term potentiation) or weakening (long-term depression). These phenomena have distinct induction pathways, but the functional outcome is usually measured as a single lumped quantity. In hippocampal CA3-CA1 synapses, we took two approaches to study the activity dependence of each phenomenon in isolation. First, we selectively blocked one process by applying kinase or phosphatase inhibitors known, respectively, to block potentiation or depression. Second, we saturated depression or potentiation and examined the activity dependence of the converse process. The resulting unidirectional learning rules could be recombined to give a well-known bidirectional frequency-dependent learning rule under the assumption that when both pathways are activated kinases dominate, resulting in potentiation. Saturation experiments revealed an additional process in which potentiated synapses can be locked at high strength. Saturability of the components of plasticity implies that the amount of plasticity contributed by each pathway depends on the initial level of strength of the synapses. Variation in the distribution of initial synaptic strengths predicts a form of metaplasticity and can account for differences in learning rules observed under several physiological and genetic manipulations. (+info)An evaluation of novel vital dyes for intraocular surgery. (7/24)
PURPOSE: To evaluate systematically the staining characteristics and safety of potential new dyes for intraocular surgery. METHODS: Six dyes were included in the investigation: light green SF (LGSF) yellowish, E68, bromophenol blue (BPB), Chicago blue (CB), rhodamine 6G, rhodulinblau-basic 3 (RDB-B3). All dyes were dissolved and diluted in a balanced saline saline solution. The light-absorbing properties of each dye were measured at a concentration of 0.05% between 200 and 1000 nm. Staining characteristics were examined by staining lens capsule tissue and epiretinal membranes (ERMs), removed intraoperatively, with dye concentrations of 1.0%, 0.5%, 0.2%, and 0.05%. Enucleated porcine eyes (postmortem time, 9 hours) were also stained. Dye-related toxicity was evaluated by a colorimetric test (MTT) measuring the inhibition of retinal pigment epithelium (RPE) cell proliferation (ARPE-19 and primary human RPE cells, passages 3-6). Cell viability was also quantified based on a two-color fluorescence cell-viability assay. Dyes were investigated in concentrations of 0.2% and 0.02%. RESULTS: All dyes investigated in this study stained human lens capsules, removed intraoperatively; ERMs, peeled during macular pucker surgery; and enucleated porcine eyes, depending on the concentration applied. The long-wavelength absorption maximum of the dyes was within the range of 527 to 655 nm at concentrations of 0.05%. Rhodamine G6 and RDB-B3 showed adverse effects on ARPE-19 cell proliferation at a concentration of 0.2% and were excluded from further investigation in primary RPE cells. The remaining four dyes showed no toxic effect on ARPE-19 and primary RPE cell proliferation at concentrations of 0.2% and 0.02%. Cell viability was affected by LGSF yellowish (0.2%) and CB (0.2% and 0.02%). Two dyes (E68 and BPB) showed no relevant toxicity in vitro. CONCLUSIONS: The systematic evaluation of dyes for intraocular use seems mandatory. In this study four dyes were identified with effective staining characteristics, with two of these dyes having no detectable toxic effect on RPE cells in vitro. (+info)Administration of novel dyes for intraocular surgery: an in vivo toxicity animal study. (8/24)
PURPOSE: To investigate the effect of intravitreal injections of new vital dyes on the retina, the retinal pigment epithelium (RPE) and the choroid in an in vivo rat model. METHODS: Rats were injected intravitreally with four dyes: light-green SF yellowish (LGSF), copper(II)phthalocyanine-tetrasulfonic acid (E68), bromphenol blue (BPB), and Chicago blue (CB) dissolved in physiologic saline solution (PSS) at concentrations of 0.5% and 0.02%. PSS served as the control. Additional animals were treated with single injections of 0.5%, 0.02%, 0.002%, and 0.0002% ICG or 0.002% E68 into one eye. Adverse effects on anterior and posterior segments were evaluated by slit lamp biomicroscopy and ophthalmoscopy. Retinal toxicity was assessed by histology and retinal ganglion cell (RGC) quantification 7 days after dye administration. RESULTS: Eyes treated with 0.5% E68, 0.5% ICG, or 0.5% CB showed discrete staining of both cornea and lens not seen at lower concentrations or with other dyes. Histology revealed dose-dependent reactions after E68 administration. ICG 0.5% induced significant thinning of inner retinal layers compared with PSS. ICG 0.02% caused focal degenerative changes of the outer retina in three of seven eyes, whereas 0.002% and 0.0002% ICG did not. CB led to heterogeneous morphologic alterations. BPB- or LGSF-treated eyes showed normal retinal morphology. ICG at all tested concentrations induced significant RGC loss, as did E68 at 0.5% but not at lower concentrations. CONCLUSIONS: BPB or LGSF produced no significantly detectable toxic effects on the retina in vivo. The safety of these new dyes must be established in other models and/or in preclinical studies before the clinical use of any of these dyes. (+info)Lissamine Green Dyes are a type of diagnostic dye used in ophthalmology to assess the health and integrity of the tear film and the corneal surface. These dyes have a green color and are often used in conjunction with other dyes like fluorescein. When applied to the eye, Lissamine Green Dyes selectively stain areas of the eye that have been damaged or disrupted, such as areas of dryness, irritation, or inflammation.
The dye binds to denatured proteins and cellular debris on the surface of the eye, highlighting any abnormalities in the tear film or corneal epithelium. Lissamine Green Dyes can help diagnose conditions such as dry eye syndrome, exposure keratopathy, and corneal abrasions. The dye is generally considered safe for use in diagnostic procedures, but it should be used with caution and according to proper protocols to minimize any potential risks or discomfort to the patient.
Indocyanine green (ICG) is a sterile, water-soluble, tricarbocyanine dye that is used as a diagnostic agent in medical imaging. It is primarily used in ophthalmology for fluorescein angiography to examine blood flow in the retina and choroid, and in cardiac surgery to assess cardiac output and perfusion. When injected into the body, ICG binds to plasma proteins and fluoresces when exposed to near-infrared light, allowing for visualization of various tissues and structures. It is excreted primarily by the liver and has a half-life of approximately 3-4 minutes in the bloodstream.
Dry eye syndrome, also known as keratoconjunctivitis sicca, is a condition characterized by insufficient lubrication and moisture of the eyes. This occurs when the tears produced by the eyes are not sufficient in quantity or quality to keep the eyes moist and comfortable. The medical definition of dry eye syndromes includes the following symptoms:
1. A gritty or sandy sensation in the eyes
2. Burning or stinging sensations
3. Redness and irritation
4. Blurred vision that improves with blinking
5. Light sensitivity
6. A feeling of something foreign in the eye
7. Stringy mucus in or around the eyes
8. Difficulty wearing contact lenses
9. Watery eyes, which may seem contradictory but can be a response to dryness
10. Eye fatigue and discomfort after prolonged screen time or reading
The causes of dry eye syndromes can include aging, hormonal changes, certain medical conditions (such as diabetes, rheumatoid arthritis, lupus, Sjogren's syndrome), medications (antihistamines, decongestants, antidepressants, birth control pills), environmental factors (dry air, wind, smoke, dust), and prolonged screen time or reading.
Treatment for dry eye syndromes depends on the severity of the condition and its underlying causes. It may include artificial tears, lifestyle changes, prescription medications, and in some cases, surgical procedures to improve tear production or drainage.
The dye dilution technique is a method used in medicine, specifically in the field of pharmacology and physiology, to measure cardiac output and blood volume. This technique involves injecting a known quantity of a dye that mixes thoroughly with the blood, and then measuring the concentration of the dye as it circulates through the body.
The basic principle behind this technique is that the amount of dye in a given volume of blood (concentration) decreases as it gets diluted by the total blood volume. By measuring the concentration of the dye at two or more points in time, and knowing the rate at which the dye is being distributed throughout the body, it is possible to calculate the cardiac output and blood volume.
The most commonly used dye for this technique is indocyanine green (ICG), which is a safe and non-toxic dye that is readily taken up by plasma proteins and has a high extinction coefficient in the near-infrared region of the spectrum. This makes it easy to measure its concentration using specialized equipment.
The dye dilution technique is a valuable tool for assessing cardiovascular function in various clinical settings, including during surgery, critical care, and research. However, it requires careful calibration and standardization to ensure accurate results.
Herpetic keratitis is a specific type of keratitis (inflammation of the cornea) that is caused by herpes simplex virus (HSV) infection. It is further divided into two types: dendritic and disciform keratitis. Dendritic keratitis is characterized by the development of branching ulcers on the surface of the cornea, while disciform keratitis involves inflammation and opacity in the stroma (middle layer) of the cornea. Both types of herpetic keratitis can cause symptoms such as eye pain, redness, sensitivity to light, tearing, and blurred vision. If left untreated, herpetic keratitis can lead to serious complications, including blindness.
Rhodamines are not a medical term, but rather a class of chemical compounds that are commonly used as dyes and fluorescent tracers in various fields, including biology, chemistry, and material science. They absorb light at one wavelength and emit it at another, longer wavelength, which makes them useful for tracking and visualizing processes in living cells and tissues.
In a medical context, rhodamines may be used as part of diagnostic tests or procedures, such as in fluorescence microscopy or flow cytometry, to label and detect specific cells or molecules of interest. However, they are not typically used as therapeutic agents themselves.
Coloring agents, also known as food dyes or color additives, are substances that are added to foods, medications, and cosmetics to improve their appearance by giving them a specific color. These agents can be made from both synthetic and natural sources. They must be approved by regulatory agencies such as the U.S. Food and Drug Administration (FDA) before they can be used in products intended for human consumption.
Coloring agents are used for various reasons, including:
* To replace color lost during food processing or preparation
* To make foods more visually appealing
* To help consumers easily identify certain types of food
* To indicate the flavor of a product (e.g., fruit-flavored candies)
It's important to note that while coloring agents can enhance the appearance of products, they do not affect their taste or nutritional value. Some people may have allergic reactions to certain coloring agents, so it's essential to check product labels if you have any known allergies. Additionally, excessive consumption of some synthetic coloring agents has been linked to health concerns, so moderation is key.
Rose Bengal is not a medical term per se, but a chemical compound that is used in various medical applications. It's a dye that is primarily used as a diagnostic stain to test for damaged or denatured cells, particularly in the eye and mouth. In ophthalmology, a Rose Bengal stain is used to identify damage to the cornea's surface, while in dentistry, it can help detect injured oral mucosa or lesions.
The dye works by staining dead or damaged cells more intensely than healthy ones, allowing healthcare professionals to visualize and assess any abnormalities or injuries. However, it is important to note that Rose Bengal itself is not a treatment for these conditions; rather, it is a diagnostic tool used to inform appropriate medical interventions.
In medical terms, "tears" are a clear, salty liquid that is produced by the tear glands (lacrimal glands) in our eyes. They serve to keep the eyes moist, protect against dust and other foreign particles, and help to provide clear vision by maintaining a smooth surface on the front of the eye. Tears consist of water, oil, and mucus, which help to prevent evaporation and ensure that the tears spread evenly across the surface of the eye. Emotional or reflexive responses, such as crying or yawning, can also stimulate the production of tears.
The cornea is the clear, dome-shaped surface at the front of the eye. It plays a crucial role in focusing vision. The cornea protects the eye from harmful particles and microorganisms, and it also serves as a barrier against UV light. Its transparency allows light to pass through and get focused onto the retina. The cornea does not contain blood vessels, so it relies on tears and the fluid inside the eye (aqueous humor) for nutrition and oxygen. Any damage or disease that affects its clarity and shape can significantly impact vision and potentially lead to blindness if left untreated.
'Staining and labeling' are techniques commonly used in pathology, histology, cytology, and molecular biology to highlight or identify specific components or structures within tissues, cells, or molecules. These methods enable researchers and medical professionals to visualize and analyze the distribution, localization, and interaction of biological entities, contributing to a better understanding of diseases, cellular processes, and potential therapeutic targets.
Medical definitions for 'staining' and 'labeling' are as follows:
1. Staining: A process that involves applying dyes or stains to tissues, cells, or molecules to enhance their contrast and reveal specific structures or components. Stains can be categorized into basic stains (which highlight acidic structures) and acidic stains (which highlight basic structures). Common staining techniques include Hematoxylin and Eosin (H&E), which differentiates cell nuclei from the surrounding cytoplasm and extracellular matrix; special stains, such as PAS (Periodic Acid-Schiff) for carbohydrates or Masson's trichrome for collagen fibers; and immunostains, which use antibodies to target specific proteins.
2. Labeling: A process that involves attaching a detectable marker or tag to a molecule of interest, allowing its identification, quantification, or tracking within a biological system. Labels can be direct, where the marker is directly conjugated to the targeting molecule, or indirect, where an intermediate linker molecule is used to attach the label to the target. Common labeling techniques include fluorescent labels (such as FITC, TRITC, or Alexa Fluor), enzymatic labels (such as horseradish peroxidase or alkaline phosphatase), and radioactive labels (such as ³²P or ¹⁴C). Labeling is often used in conjunction with staining techniques to enhance the specificity and sensitivity of detection.
Together, staining and labeling provide valuable tools for medical research, diagnostics, and therapeutic development, offering insights into cellular and molecular processes that underlie health and disease.