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Results for “Microscopy, Polarization”

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PubMed1991

Quantitative assessment of the age of fibrotic lesions using polarized light microscopy and digital image analysis.

Reliable histologic methods for gauging the maturity of fibrotic lesions are limited, making interventions in the healing process difficult to assess. As collagen ages there is enhanced birefringence due to increased molecular and fibrillar organization. The purpose of this study was to develop a microscopal technique to quantify this process and to determine its ability to distinguish scars of varying ages. Fibrosis in the rat gracilis muscle was studied 5 to 63 days after superficial injury. Sections were stained with picrosirius red and illuminated with monochromatic, polarized light. The microscope fields were digitized using a computer-video system yielding an image in which noncollagenous material was dark (gray level 0) and collagen was depicted by grey levels 1 to 255. In the fibrosis model used, the collagen area fraction plateaued at 80% by day 21. The median collagen grey level increased progressively as the scar aged. It is concluded that this histologic, nondestructive technique can reliably quantify age-related optical properties of fibrotic collagen and that this could be used to determine the maturity of fibrotic lesions.

Aging↗

PubMedDate not supplied

Microscopical advances in assisted reproduction.

In a series of papers carried out by this laboratory it was demonstrated that the quality of sterile males sperm, assessed submicroscopically and mathematically, is closely correlated with the success of the various procedures of assisted reproduction. If we attempt to select hypothetically optimal spermatozoa destined to the ICSI by light inverted microscopy, a considerable amount of ultrastructural information is lost and our selection is merely based on the motility. In this study we apply polarization microscopy to the ICSI technique, introducing polarizing and analyzing lenses in an inverted microscope model, operating in a transparent container. The retardation of the birefringence in the various organelles is evaluated by compensators, and the images are transmitted to a video system, and stored in a computer. Spermatozoa are maintained alive and perfectly motile in this polarizing inverted microscope, and the character of the birefringence is the same as in fixed and sectioned biological material examined by polarization microscopy. The birefringence of the sperm structures allows a sperm analysis closer to TEM than to phase contrast light microscopy analysis.

Acrosome↗

PubMed1984

Physicochemical characterization of the urinary lipid from humans with nephrotic syndrome.

The aim of this study was to investigate the nature of urinary lipid in humans with nephrotic syndrome. Fresh urine specimens were fractionated by centrifugation into a lower cellular fraction and an upper noncellular fraction. Of the 11 urine specimens examined, six cellular fractions contained cells (oval fat bodies) that were laden with anisotropic (birefringent) droplets when viewed by polarizing microscopy. The mean total cholesterol excretions for the five urine specimens without anisotropic droplets and the six urine specimens with anisotropic droplets were 8.7 mg/L and 35.5 mg/L, respectively. The cellular fractions of the six urine specimens with anisotropic droplets are enriched in cholesterol esters relative to whole urine. Upon heating, the anisotropic droplets underwent phase transitions characteristic of cholesterol esters, as observed by polarizing microscopy. The mean cholesteric to isotropic phase transition temperature of the anisotropic droplets was 41.3 degrees C. These data indicate that the anisotropic droplets of the oval fat bodies were composed of cholesterol esters acylated largely with monounsaturated fatty acids consistent with cellular origin. The noncellular fractions were subjected to ultracentrifugation (48,000 X g for 2 hours) and then separated into supernate and infranate fractions. The supernate fractions contained minor amounts of lipid, except in two cases of massive lipiduria. In these two cases, the supernate fractions contained many individual anisotropic droplets with lipid composition nearly identical to their cellular fractions. The dispersed lipid of the infranate fractions were invisible by microscope. Nine of the 11 infranate fractions revealed an alpha migrating lipid band by agarose gel electrophoresis. For urine specimens with anisotropic droplets, the infranate fractions contained cholesterol ester fatty acids that were less saturated (as measured by gas-liquid chromatography) than the cellular fractions. Thus, the cholesterol esters of the infranate fractions were derived from a different source (probably high-density lipoproteins) than the cholesterol esters of the cellular fractions.

Adolescent↗

PubMed2001

Z-polarized confocal microscopy.

In light microscopy the transverse nature of the electromagnetic field precludes a strongly focused longitudinal field component, thus confining polarization spectroscopy and imaging to two dimensions (x,y). Here we describe a simple confocal microscopy arrangement that optimizes for signal from molecules with transition dipoles oriented parallel to the optic axis. In the proposed arrangement, we not only generate a predominant longitudinally (z) polarized focal field, but also engineer the detection scheme in such a way that in a bulk of randomly oriented molecules, the microscope's effective point-spread function is dominated by the contribution of those molecules that are oriented along the optic axis. Our arrangement not only implicitly allows for the determination of the orientation of transition dipoles of single molecules in three dimensions, but also highlights the contribution of z-oriented molecules in three-dimensional imaging.

Microscopy, Confocal↗

PubMed2001

Z-polarized confocal microscopy.

Microscopy, Confocal↗

PubMed1990

[Study of crystalline structures of the bile in the diagnosis of cholelithiasis].

Under analysis were results of polarization microscopy of bile in 111 patients with cholelithiasis, 8 patients with acalculous cholecystitis and 8 practically healthy people. It was found that in healthy people there are no crystalline structures in the initial state of bile. The composition of bile from patients with cholelithiasis is characterized by the presence of three types of crystals: solid crystals of cholesterol monohydrate, calcium bilirubinate granules and calcium carbonate microspherolites. Polarization microscopy of bile may be used as a sufficiently simple method of diagnostics of stone disease.

Adult↗

PubMed1990

A-band shortening in single fibers of frog skeletal muscle.

The question of whether A-bands shorten during contraction was investigated using two methods: high-resolution polarization microscopy and electron microscopy. During shortening from extended sarcomere lengths in the passive state, sarcomere-length changes were essentially accounted for by I-band shortening. During active shortening under otherwise identical conditions, the sarcomere length change was taken up approximately equally by A- and I-bands. Several potential artifacts that could give rise to apparent A-band shortening were considered and judged unlikely. Results obtained with polarization microscopy were similar to those obtained with electron microscopy. Thus, modest but significant thick filament shortening appears to occur during active sarcomere shortening under physiological conditions.

Animals↗

PubMedDate not supplied

Fabric organization of the subendothelium of the human brain artery by polarized-light microscopy.

The thickened subendothelium of brain arteries that is characteristic of atherosclerosis was assessed for the directional organization of the two main birefringent components, smooth muscle cells and collagen. Thirty-three arteries from 16 autopsy cases were pressure fixed at 30, 60, 110, and 200 mm Hg, sectioned at a thickness of 7 microns , and stained with silver impregnation to enhance tissue birefringence. The intended focus of the study was on muscle organization, but it also included the collagen among the cells because of the coalignment of the two tissues and their similar staining properties for polarized-light microscopy. The birefringent medial fabric at all pressures was circumferentially oriented, with a mean deviation of the 33 sections of 1.4 degrees from circumferential with an average circular standard deviation of 3.5 degrees, thereby showing remarkable coherence. In contrast, the subendothelium showed great variability both in thickness and in organization. Many arteries had no measurable subendothelium, and others had as much as 100%, with some atherosclerotic lesions as much as 300% of the medial width. Measurements from the subendothelium revealed a helical arrangement of tissue, often divided into separate regions, with a balance of left- and right-handed helical components and generally with lower pitch angles in the layers adjacent to the lumen. The average circular standard deviation within individual subendothelial layers was 14.5 degrees.

Adult↗

PubMed1995

Atrioventricular valves of the mouse: II. Light and transmission electron microscopy.

BACKGROUND: Mouse atrioventricular (AV) valves present a number of conspicuous morphologic differences with human AV valves. Given the existence of these differences, it is important to know the structural organization of mouse AV valves. Since the mouse is often considered to be a good animal model for developmental and anatomical studies, the presence of significant differences in structure may render comparative studies difficult. In addition, we wished to learn about the existence of structural changes in the mouse AV valves with age. METHODS: The structural organization of mouse AV valves from 21 days to 1 year of age was studied by polarizing microscopy and by conventional light and transmission electron microscopy. RESULTS: Polarizing microscopy reveals the presence of a system of birefringent fibers that consist of collagen bundles that organize like tendons. The spatial organization of these fibers is different in the two AV valves, reflecting differences in the anatomy of the entire valvular complex. Interstitial cells (IC) are of two different phenotypes: some are typical fibroblasts, while some others share smooth muscle cell characteristics. In addition, small areas of fibrocartilage are also observed. The compactness and thickness of the collagen bundles increase with age. Also with age, the basement membranes become thickened or multilayered, and matrix vesicles and deposits of amyloid P can be observed. CONCLUSIONS: The collagenous birefringent fibers form an internal skeleton that should transmit the cycling stress evenly over the entire leaflets. IC should help to maintain the structure and deformability of the valve tissue and appear actively involved in the synthesis and renewal of extracellular material. The cartilaginous foci appear to be a normal component of the valve tissue. The structural changes observed in old animals appear to be related to the degenerative processes which take place in normal valvular tissues with age. Despite the structural differences, age changes appear to be similar in the AV valves of mouse and man.

Aging↗

PubMed2005

Imaging melanoma in a murine model using reflectance-mode confocal scanning laser microscopy and polarized light imaging.

The light-scattering properties of cutaneous tissues provide optical contrast for imaging the presence and depth of pigmented melanoma in a highly pigmented murine model, the C57/B6 mouse. Early lesions are difficult to identify when viewing black lesions on a black mouse. Two methods were used to image early lesions in this model. (1) A reflectance-mode confocal scanning laser microscope (rCSLM) was built to provide horizontal images (x-y at depth z) and transverse images (x-z at position y) non-invasively in the living mouse. (2) A polarized light imaging (PLI) camera was built using a linearly polarized white light source that viewed the skin through an analyzing linear polarizer oriented either parallel or perpendicular to the illumination's polarization to yield two images, "PAR" and "PER," respectively. The difference image, PAR-PER, eliminated multiply scattered light and yielded an image of the superficial but subsurface tissues based only on photons scattered once or a few times so as to retain their polarization. rCSLM could image melanoma lesions developing below the epidermis. PLI could distinguish superficial from deeper melanoma lesions because the melanin of the superficial lesions attenuated the PAR-PER image, whereas deeper lesions failed to attenuate the PAR-PER image.

Animals↗

PubMed1983

[Selected light microscopy and polarization optical studies of implant-bone interfaces].

Implant bone specimen of inert materials and of the material BVK Ap 40 mended histologically. The bone specimen were both decalcified and carried to the polish technique after plastics embedding. The experiments were carried out in miniature swines (type Mini-Lewe) and rabbits. Microscopical and polarisation optical investigations were carried out. A connective-tissue membrane was provable at the interface implant-bone in all cases with use of the biocompatible material titanium. With BVK Ap 40 was observed a direct compound with the bone.

Animals↗

PubMed2001

[Scanning electron microscopy and light microscopy under polarized light of a submandibular salivary gland calculus].

BACKGROUND: The salivary calculus is an ancient pathologic condition, called sublingual stone by Hyppocrates. It is well-defined from a anatomo-pathologic, diagnostic and topographic viewpoint, though some pathogenesis-related doubts still exist. This work aims at relating the micro-morpho-structural aspect of a salivary calculus of remarkable dimensions with the current calculogenetic hypotheses. METHODS: A 1.1 g salivary calculus removed from the initial section of Wrthon s duct in the right-hand submandibular gland of a 42 year old male has been studied. Following the fixation in 4% buffered formalin and the inclusion in resin, it was serially sectioned in 15-20 micron slices. Some sections were coloured with toluidine blue O and acid fuchsin. The exeresis of the calculus was carried out intraorally, with marsupialization under local anesthesia. The analysis was performed using a SEM with backscattered electrons and a polarised and transmitted light microscope. RESULTS: The investigations have outlined the presence of various organic cores and a concentric, stratiform architecture interrupted by radial elements. CONCLUSIONS: The formation of this calculus may be due to mixed secondary lithiasis resulting from the formation of colloids and crystalloids.

Adult↗

PubMed2003

Image analysis of tendon helical superstructure using interference and polarized light microscopy.

Wave-like structures (WLS also known as crimp) have generally been reported to be planar structures. However, there is evidence that a helical superstructure, rather than a planar one, should be considered. Conditions dictated by supramolecular chemistry, molecular recognition and self-assembly favor the idea of a helical arrangement for collagen bundles in a supramolecular structure. The aim of this work is to provide additional data in support of a helical superstructure for collagen bundles in tendons. Cryosections of fixed flexor bovine tendons and sections of resin-embedded peeled rat tail were studied using polarized light, interference, and phase contrast microscopy. Image analysis was used to find appropriate mathematical descriptors for WLS. Interference colors due to the dispersion of birefringence allowed the detection of a gradual, intertwined twisted fiber organization in WLS, as the angle of the tendon axis was rotated relative to the polarizers. Helical movements of the images of the WLS bands were produced using animation methods. Interference microscopy revealed interference colors associated with different orientations and dry mass concentrations in the fibers, especially in tendon cross-sections, which also exhibited Maltese-cross birefringence images. Similar images were detected by interference microscopy, suggesting a spiral organization of fibers in the section plane. The helical orientation of the fibers was detected by focusing through different planes of sections. Based on a comparison of this superstructure with mesophases, the twisted grain boundary concept is considered to be the most appropriate for the classification of tendon WLS.

Animals↗

PubMedDate not supplied

In utero diagnosis of trichothiodystrophy by endoscopically-guided fetal eyebrow biopsy.

OBJECTIVE: To describe the prenatal diagnosis of trichothiodystrophy (TTD) through endoscopically-guided fetal eyebrow biopsy. MATERIALS AND METHODS: A 32-year-old patient, gravida 4, para 3, with a history of 2 previous infants affected with TTD was referred at 17(5)/(7) weeks for fetal hair biopsy. DNA repair studies had been normal in the previous children. Four 1-mm biopsies were obtained from the external aspect of the fetal eyebrows under direct endoscopic guidance. Fetal hair samples were assessed with polarized microscopy, electron microscopy, hematoxylin and eosin staining, and were also sent for analysis of sulfur content (cystine levels). RESULTS: The fetal eyebrows were the only adequate source of hair in the early second trimester. The biopsy samples yielded adequate material for all tests. Polarized microscopy showed characteristic banding patterns, but trichoschisis was not apparent. Cystine levels (19 micromol/l) in the biopsy sample were significantly lower than an age-matched (fresh spontaneous abortion) control (368 micromol/l). CONCLUSION: Prenatal diagnosis of TTD is possible in the second trimester through endoscopically-guided eyebrow biopsy. An adequate amount of hair is present in the eyebrows by then, and the disease is already manifest. Analysis of sulfur content of the hair samples is preferred over polarized or electron microscopy, as many classic microscopic findings of TTD may not be present in the early second trimester.

Adult↗

PubMedDate not supplied

Diagnostic value of fine needle aspiration cytology in gouty tophi: a report of 7 cases.

UNLABELLED: BACKGROUND The diagnosis of gout can be problematic when the presentation is atypical and serum uric acid is borderline elevated. Demonstration of monosodium urate (MSU) crystals in fine needle aspiration (FNA) smears from nodular masses clinically suspected to be tophi establishes the diagnosis unequivocally. CASES: Of the 7 cases in this study, 4 were suspected clinically to have gouty tophi. Giant cell tumor of tendon sheath, giant cell tumor of bone and metastatic tumor with multicentric involvement of bone were the clinical diagnoses in 1 case each. Serum uric acid levels high enough to be in the diagnostic range for gout were reported in 3 cases, within normal limits in 3 cases and low in 1 chronic alcoholic patient. Bright field microscopy of FNA smears revealed singly scattered or stacks of MSU crystals with variable number of inflammatory cells, with or without foreign body giant cells in 6 cases. In 1 patient, FNA showed stacks of MSU crystals only. Characteristic birefringence of MSU crystals was observed on polarizing microscopy. CONCLUSION: FNA demonstration of MSU crystals on polarizing microscopy can easily establish the nature of the nodules in and around the joints and in soft tissue as gouty tophi and is thus an investigation differentiating this lesion from other masses clinically simulating it.

Adult↗

PubMed2000

[A study of the mechanism of effects of solution containing trace elements on remineralization layer formation of enamel carious lesions].

OBJECTIVE: To study the effects of several remineralization solutions with different composition on the artificial demineralization lesions of bovine enamel and the mechanism of remineralization layer formation. METHODS: 36 bovine teeth were selected and artificial carious lesions were formed with lactic acid gel. Then all specimens were divided into 4 groups which contained no fluoride, fluoride, fluoride-calcium-phosphate-tin, and de-ionic water separately, and the de-ionic group was taken as control. The structure and composition of the sediments on the enamel surface were evaluated and detected by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Histological change of enamel section was examined by polarized microscopy. RESULTS: Compared with the control group, all the solutions had remineralization effects, especially the solutions containing trace elements. XPS showed that there were sediments formed on the surface of carious lesion, the compositions of the sediments were CaF2, HAP and non-specifically absorbed fluoride (NSAF). Irregular, crystal deposits were also found under SEM on the enamel surface. The polarized microscopy results showed that the observed demineralization areas decreased after exposure to the solutions. CONCLUSION: Solutions containing fluoride and trace elements were effective on remineralization. The possible mechanism is that CaF2 and NSAF, instead of FA formed in the remineralization layer. Moreover, the remineralization effects of the fluoride solutions containing trace elements are more outstanding than that without trace elements. The potential mechanism is the synergistic action of fluoride and trace elements.

Animals↗

PubMed2001

Polarized fluorescence microscopy of individual and many kinesin motors bound to axonemal microtubules.

Kinesin is a molecular motor that interacts with microtubules and uses the energy of ATP hydrolysis to produce force and movement in cells. To investigate the conformational changes associated with this mechanochemical energy conversion, we developed a fluorescence polarization microscope that allows us to obtain information on the orientation of single as well as many fluorophores. We attached either monofunctional or bifunctional fluorescent probes to the kinesin motor domain. Both types of labeled kinesins show anisotropic fluorescence signals when bound to axonemal microtubules, but the bifunctional probe is less mobile resulting in higher anisotropy. From the polarization experiments with the bifunctional probe, we determined the orientation of kinesin bound to microtubules in the presence of AMP-PNP and found close agreement with previous models derived from cryo-electron microscopy. We also compared the polarization anisotropy of monomeric and dimeric kinesin constructs bound to microtubules in the presence of AMP-PNP. Our results support models of mechanochemistry that require a state in which both motor domains of a kinesin dimer bind simultaneously with similar orientation with respect to the microtubule.

Actin Cytoskeleton↗

PubMed1980

Trichothiodystrophy: sulfur-deficient brittle hair as a marker for a neuroectodermal symptom complex.

Trichothiodystrophy, or sulfur-deficient brittle hair, is a clinical marker for a neuroectodermal symptom complex that usually features mental and physical retardation and may also include nail dystrophy, lamellar ichthyosis, ocular dysplasia, dental caries, and decreased fertility. Cystine-deficient hair is common to all patients. The hairs from two new patients were studied, and the most distinctive microscopic hair findings were striking bright and dark bands seen with polarizing microscopy using crossed polarizers. To date, all hair samples showing this banding have had an abnormally low sulfur content. Two-dimensional electrophoresis on the two protein fractions of the abnormal hair confirmed that the abnormality is caused by decreased synthesis of high-sulfur matrix proteins. Disturbances of the transport or utilization of sulfur-containing amino acids in other neuroectodermal tissues may be proposed to account for the various disease features in these persons.

Adult↗