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At least 1,189 records · Page 66Linked to original sources
PubMed2000

Immunoelectron microscopy links molecules and morphology in the studies of keratinization.

It is impossible to understand keratinization disorders without knowing what is going on at molecular levels. We and others have been analyzing the issues of keratinization by means of (immuno)electron microscopy and found that this is quite a useful tool for molecular pathology. We summarize the recent advances in the biology and pathology of keratinization at ultrastructural and molecular levels. Tonofilaments, a morphological hallmark of keratinocytes, are composed of keratins. Epidermolytic hyperkeratosis, a genetic disease of keratin K1/K10, shows clumped tonofilaments that are shown to be actually composed of K1/K10 by immunoelectron microscopy. Distribution of profilaggrin and its derivatives has also been revealed by immunoelectron microscopy. Defective interaction between keratin and filaggrin is seen in epidermolytic hyperkeratosis. Transient nuclear localization of N-terminal domains of profilaggrin is observed in the transitional cells of normal epidermis. Unique distribution of trichohyalin was detected in psoriasis. Distribution of various components of cornified cell envelopes including involucrin and loricrin in normal and abnormal keratinization can also be detected with this technique. Premature formation of involucrin-rich cell envelopes are observed in psoriasis vulgaris. Defects in cross-linking of loricrin are detected in transglutaminase 1 knockout mice, the animal model of lamellar ichthyosis. Abnormal distribution of loricrin has been detected in genetic diseases of loricrin (loricrin keratoderma). By combining immunoelectron microscopy and terminal deoxynucleotidyl transferase-mediated dUDP nick-end labeling (TUNEL) methods, the nature of TUNEL positive cells has also been unravelled.

DNA Fragmentation↗
PubMed2001

Provider-performed microscopy.

The category of provider-performed microscopy was defined in the Federal Register to provide a unique regulatory approach for bright-field and phase-contrast microscopy performed by a physician, dentist, or midlevel practitioner examining labile specimens. A CLIA certificate for this category of testing is available, which also permits the performance of waived tests. Because these provider-performed microscopy procedures do not have quality-control materials available, special challenges are encountered in establishing and monitoring such testing within a hospital. Vigilance is required to maintain a provider-performed microscopy program within a hospital.

Adult↗
PubMedDate not supplied

Potentials of radio-frequency field gradient NMR microscopy in environmental science.

An understanding of transport, flow, diffusivity and mass transfer processes is of central importance in many fields of environmental biotechnology such as biofilm, bioreactor and membrane engineering, soil and groundwater bioremediation, and wastewater treatment. Owing to its remarkable sensitivity to molecular displacements and to its noninvasive and nondestructive character, pulsed field gradient (PFG) nuclear magnetic resonance (NMR) can be a valuable tool for investigating such processes. In conventional NMR microscopy, spatial encoding is achieved by using static magnetic field gradients (B0 gradients). However, an interesting alternative is to use radio-frequency magnetic field gradients (RF or B1 gradients). Although the latter are less versatile than the former, RF field gradient microscopy is particularly suitable for dealing with heterogeneous systems such as porous media because of its quasi-immunity to background static magnetic field gradients arising from magnetic susceptibility inhomogeneities, unlike the B0 gradients microscopy. Here, we present an overview of basic principles and the main features of this technique, which is still relatively unused. Different examples of diffusion imaging illustrate the potentialities of the method in both micro-imaging and the measurement of global or local diffusion coefficients within membranes and at liquid-solid interfaces. These examples suggest that a number of environmental problems could benefit from this technique. Different future prospects of application of B1 gradient NMR microscopy in environmental biotechnology are considered.

Biotechnology↗
PubMedDate not supplied

Microscopy as a tool for renal research.

Microscopy has always played an important role in renal research as a tool to visualize events occurring at the surface of the kidney and as a method to investigate intracellular ion activity and membrane transport. Thanks to the recent advances in fluorochromes as ionic detector agents and as a means to label antibodies, microscopy will maintain its role at the forefront of renal research in the future. This article presents an overview of fluorescence microscopy and then focuses on some of the present applications of microscopy to exam renal epithelial tissues. Other areas covered are the pros and cons of various techniques and their applications to renal research.

Animals↗
PubMed2002

Cornea in Marfan disease: Orbscan and in vivo confocal microscopy analysis.

PURPOSE: To investigate corneal thickness, curvature, and morphology with the Orbscan Topography System I (Bausch & Lomb, Inc., Salt Lake City, UT) in patients with Marfan syndrome (MFS) and to study MFS with in vivo confocal microscopy. METHODS: This prospective, clinical, comparative case series included 60 eyes of 31 patients with MFS and 32 eyes of 17 control subjects. First, biomicroscopic examination was conducted to search for ectopia lentis. Then, mean keratometry and ocular refractive power were calculated by the autokeratorefractometer. In each group, the Orbscan System I mean (and mean simulated) keratometry and pachymetric measurements (at the central location and at eight midperipheral locations) were obtained and compared, and correlations were established. In vivo confocal microscopy was performed to evaluate tissue morphology and Z-scan analysis of 14 thin MFS corneas compared with 14 control corneas. RESULTS: A significant decrease (ANOVA, P < 0.0001) of mean simulated keratometry measurement appeared in the MFS group (sim K, 40.8 +/- 1.4 D) compared with the control group (42.9 +/- 1.1 D). Pachymetry in the MFS group was significantly decreased (P < 0.0001) compared with that in the control group, in the center (respectively, 502 +/- 41.9 microm and 552 +/- 23.6 microm) and the eight midperipheral locations. Ectopia lentis was highly linked with mean keratometry and pachymetry (P < 0.0001). Confocal microscopy performed on MFS-affected thin corneas confirmed the corneal thinning and showed an opaque stromal matrix, and Z-scan profiles were abnormal with increased stromal back scattering of light. CONCLUSIONS: MFS is known to be associated with a flattened cornea. This study demonstrated an association with corneal thinning and described confocal microscopy findings in this syndrome.

Adolescent↗
PubMed2002

Distribution of injected MRI contrast agents in mouse livers studied by confocal and SIMS microscopy.

OBJECTIVE: To localize magnetic resonance imaging (MRI) contrast agents injected intravenously into mouse livers. STUDY DESIGN: Parallel studies were performed on fluorescent europium and nonfluorescent, paramagnetic gadolinium and on a product combining nanoparticles of Fe and Texas Red to obtain combined information on the distribution of these molecules inside the liver. The distribution of different superparamagnetic iron oxides was also studied because the size of these new compounds is not always convenientfor microcirculation studies. RESULTS: Europium and Texas Red can be detected by confocal microscopy. Europium, iron and gadolinium can be detected by secondary ion mass spectrometry (SIMS) microscopy. Studies confirmed the complementarity of both microscopies. They also confirmed the possibility of using europium as a model of gadolinium to analyze thefate of MRI contrast agents. CONCLUSION: The methodology can be used on mice injected intravenously and analyzed by confocal and SIMS microscopy to localize MRI contrast agents inside cellular and tissue specimens of mice.

Animals↗
PubMed2003

Current role of electron microscopy in the diagnosis of pigmented tumors.

Melanoma represents the most diagnostically challenging of the group of pigmented lesions to be discussed in this review, but a number of other pigmented lesions may present diagnostic difficulties either because they are uncommon or occur in unexpected clinico-pathologic situations. With the routine use of immunohistochemistry as the initial ancillary diagnostic technique in surgical pathology, electron microscopy has been relegated to a secondary but still essential diagnostic role in a significant number of these cases. There are no stains that are 100% specific or sensitive in depicting these lesions. The practice of using immunohistochemistry first (and in many laboratories exclusively) to address diagnostic dilemmas, although appearing to be a practical and cost-effective approach, is not always the case. Once 3 or more antibodies are used to solve the diagnostic challenge, ultrastructural evaluation becomes less expensive. To solve a difficult diagnostic problem often requires testing for 4 to 5 antigens. Turn around times for both immunohistochemistry and electron microscopy are similar. Ultra-rapid (3 hours) processing of specimens for electron microscopy is available for those cases requiring immediate diagnosis. One genuine problem with using immunohistochemistry as the initial diagnostic technique is that the results may show staining patterns that can be regarded as consistent with the diagnosis of melanoma even when the diagnosis is incorrect, and the need for performing ultrastructural evaluation is never appreciated. Immunohistochemistry and electron microscopy should be considered truly complementary and it is unfortunate that utilization of both diagnostic modalities does not occur more frequently. Pathologists should be aware of the entire immuno-morphological spectrum associated with melanocytic neoplasms to be able to address diagnostic difficulties that may, arise as a consequence of the heterogeneity of these tumors.

Biomarkers, Tumor↗
PubMed2002

[Sensitivity of microscopy for detection of mycobacterium tuberculosis and MOTT (mycobacteria other than tuberculosis) on the basis of analysis 22.218 clinical materials submitted in 1998-2001 to the Department of Microbiology in National Tuberculosis and Lung Diseases Research Institute in Warsaw, Poland].

The results of 22.218 respiratory specimens sent to our laboratory were studied to determine the sensitivity of the Ziehl-Neelsen (Z-N) stain and microscopy-fluorescence method for detection of M.tbc and MOTT. There were no AIDS patients among analyzed cases. Smears were positive for acid fast bacilli (AFB) 60.0% (480 of 800) of specimens growing M. tuberculosis and 25.1% (219 of 872) of specimens growing the six common species of MOTT. Smear positivity by species was 28.1% (141 of 502) for M. kansasii, 29.4% (43 of 146) for MAIC, 28.7% (35 of 122) for M. xenopi. No smear was positive for M. gordone (43 cultures), M. fortuitum (33 cultures), M. scrofulaceum (26 cultures). The rate of nonculturable mycobacteria on L-J medium was 0.2%; mean rate of contamination was 4.6%. We also analyzed the relation between the number of AFB seen on the smear and time of the growth of M. tuberculosis and relation between abundance of the culture growth and AFB seen on smears. These study suggest that the sensitivity of microscopy for Mycobacterium tuberculosis is comparable with the data of others authors. Sensitivity of microscopy is lower in MOTT detection than for M.tbc (p < 0.001). Time of growth and abundance of the M. tuberculosis cultures were adequate to AFB seen in microscopy.

Bacteriological Techniques↗
PubMed2003

Predicting urine culture results by dipstick testing and phase contrast microscopy.

AIMS: Urine is the most frequently received clinical specimen for bacterial culture. To determine whether dipstick or microscopy results reliably predicted the presence or absence of a reportable urinary pathogen we performed dipstick testing and phase contrast microscopy on unspun urine from 500 specimens. We also investigated the relationship between the presence of squamous epithelial cells (SECs) and mixed growth on culture. METHODS: For each specimen, the presence of leukocyte esterase and urinary nitrite was recorded as well as the quantity of leukocytes (WBC), SECs, and erythrocytes. All cultures had the number and type of each organism recorded. Pyuria was defined as > or =10 WBC/mm(3). RESULTS: Specimens with <10 SEC/mm(3) had fewer isolates (0.9 isolate per culture) than specimens with > or =10 SEC/mm(3) (two isolates per culture); therefore, SEC contamination was defined as > or =10 SEC/mm(3). Of 500 specimens, 266 (53%) had no growth and 136 (27%) had mixed growth. A total of 288 (58%) specimens had negative dipstick results and completely normal microscopy. Of these, 11 (4%) had a pure growth of a urinary pathogen but the pathogen was present in only three (1%) at > or =10(5) CFU/mL. Of 413 urine specimens without SEC contamination, 323 (78%) had either no detectable growth or pure growth compared with only 41 of 87 (47%) with SEC contamination (P<0.001). Of the 413 urine specimens without SEC contamination, 90 (22%) had > or =2 organisms compared with 46 of 87 (53%) with contamination (P<0.01). Pyuria was present in only 21 of 266 (8%) urine specimens without growth but was present in 60 of 95 (64%) specimens containing a reportable pathogen (P<0.01). CONCLUSIONS: SEC contamination does not reliably predict cultures with mixed growth, urine specimens with negative dipstick results and microscopy rarely contain a reportable urinary pathogen, and screening algorithms are warranted and justified.

Adolescent↗
PubMed2005

Fine needle aspiration cytology diagnosis of gastrointestinal stromal tumors utilizing scanning electron microscopy.

BACKGROUND: Digestive stromal neoplasms are the most frequent undifferentiated mesenchymal tumors. The outcome of these malignancies is difficult to predict and the histogenesis is still controversial. However, the frequent and specific expression of CD117 (c-kit) by these tumors could imply an origin from interstitial cells of Cajal. Our objective was to analyze the role of fine needle aspiration cytology, cell block preparation, and immunocytochemistry in the interpretation of gastrointestinal stromal tumors, and to establish scanning electron microscopy as a useful research aid for pathologic changes of the surface cells of gastrointestinal stromal tumors, not totally appreciated by light microscopy. MATERIAL AND METHODS: Twelve cases of gastrointestinal stromal tumors were included in this study, in which fine needle aspiration cytology was performed. RESULTS: On aspirated material, the tumor cells formed closely packed cohesive tissue fragments with high cellular density often in bloody background, or fascicles with parallel side-by-side arrangements of the nuclei. On cell block biopsy material, gastrointestinal stromal tumors were highly cellular spindle or epithelioid tumors with basophilic appearance. Immunocytochemically, they were CD117 positive in all twelve cases, CD34 positive in nine, weakly smooth muscle actin-positive in five, and S-100 and GFAP-negative in all cases. The scanning electron microscopy study showed a strong correlation with the cytomorphological profile. CONCLUSIONS: Gastrointestinal stromal tumors show a broad morphologic variety, but nuclear pleomorphism by cytology alone, rarely correlates with malignant potential. In the appropriate clinical and radiological setting, a confident diagnosis of gastrointestinal stromal tumors can be documented by fine needle aspiration cytology, cell block, immunocytochemical, and scanning electron microscopy results.

Biopsy, Needle↗
PubMed2005

Light and scanning electron microscopy evaluation of the postnatal small intestinal mucosa development in pigs.

Modifications in the structure of gastrointestinal mucosa is often used to evaluate gut function for instance during the development or in response to particular food components. Scanning electron microscopy (SEM) gives a chance to observe the surface of the gut epithelium in three dimensions. However, this technique is seldom used due to technical difficulties. The present study attempted to investigate the intestinal mucosa structure changes in the postnatal pig using light and scanning electron microscopy technique. Experiments were carried out on sow reared piglets from birth until 38 days of age. Piglets were sacrificed at birth and at the 3(rd), 7(th), 21(st) and 38(th) day of life. The entire gastrointestinal tract was immediately harvested and the whole thickness tissue samples were taken from the duodenum, jejunum and ileum for optical and scanning electron microscopy. SEM analyses corroborated with histometry made by optical microscopy. Moreover, a number of shape modifications of the villi and its surface have been observed. The development changes in small intestine mucosa during the first 3 weeks were manifested in shape, size and density of villi. In conclusion, the structure of small intestinal mucosa undergoes profound structural changes. SEM gives a new dimension in the investigation of gut mucosa.

Animals↗
PubMed2006

Comparing the results of light microscopy with the results of PCR method in the diagnosis of Plasmodium vivax.

BACKGROUND AND OBJECTIVES: Although polymerase chain reaction (PCR) is a new technique in the diagnosis of malaria with very high accuracy; light microscopy is still conventional diagnostic method in Iran. In this study we checked the accuracy of light microscopy using the results of PCR as gold standard in Iran. METHODS: The blood samples were collected from 124 febrile cases in Kahnooj district. The blood slides were read by microscopists, and double checked by experts in provincial referral laboratory. DNA samples were processed by PCR to amplify species-specific sequences of 18s subunit ribosomal ribonucleic acid (18ssrRNA) genes of Plasmodium vivax and P. falciparum. RESULTS: The sensitivity and specificity of microscopy in the detection of Plasmodium spp infection were 77% (95% CI: 46-94%) and 100% (95% CI: 95-100%), correspondingly. Also, the estimated positive and negative predictive values were 100% (95% CI: 66-100%) and 97% (95% CI: 91-99%), respectively. INTERPRETATION AND CONCLUSION: According to these results, we believe that the accuracy of light microscopy in the diagnosis of malaria in Kahnooj was acceptable. Expert micorscopists in endemic areas of Iran such as Kahnooj and available equipments in one hand and expensive PCR test on the other hand may convince that in current situation we do not have to change the diagnostic method.

Adolescent↗
PubMed1991

[Mycobacterial infections: yield of bacillary microscopy in different clinical samples (1975-1988)].

BACKGROUND: The yield of microscopy examination as a quick diagnostic test in several pulmonary and nonpulmonary samples referred to the mycobacterial laboratory of a general hospital is reviewed. METHODS: During a 14-year period (1975-1988), 113,836 biological products were investigated. In 9,972 a positive culture for mycobacteria was obtained. For the microscopy examination the auramin technique was used; if positive, acid-alcohol resistance was confirmed by overstaining with the Ziehl-Neelsen technique. The culture was used as the reference method. RESULTS: Microscopic examination was positive in 34% of samples with a positive culture, being 39% for Mycobacterium tuberculosis and 10% for environmental mycobacteria. The overall specificity was 99%, the positive predictive value was 91% and the negative predictive value was 94%. In pleuropulmonary samples the sensitivity ranged from 48% in sputum and 2% in pleural biopsy, with specificity higher than 99%. In nonpulmonary samples, sensitivity, specificity and positive and negative predictive values varied with the type of sample. The false positive rate (positive microscopy with negative culture) was 0.3, and it was shown that 80% of these patients had received previous therapy. In organic fluids (pleural, peritoneal, cerebrospinal), the sensitivity was not greater than 13%. CONCLUSIONS: Sputum, bronchoaspirate and bronchoalveolar lavage were better for the diagnosis of tuberculosis than gastric aspirate. Approximately 1 in each positive microscopy examinations corresponded to environmental mycobacteria. In some nonpulmonary samples with high sensitivity the positive predictive value was low. 80% of the false positive results corresponded to previously treated patients.

Bacteriological Techniques↗
PubMed1991

[Significance of electron microscopy in the diagnosis of undifferentiated neoplasms of the nose and nasal sinuses].

Undifferentiated neoplasms of nose and nasal sinuses are very rare. They are very difficult to diagnose by both light and electron microscopies. Twelve cases of undifferentiated neoplasms of nose and nasal sinuses were collected and the morphological features under light and electron microscopes compared histologically. The results showed that correct diagnoses were only obtained in six cases by light microscopy. The other six cases were diagnosed by electron microscopy as malignant melanomas in two cases, leiomyosarcoma in one case, olfactory neuroblastomas in two cases and malignant fibrous histiocytoma in one case. It showed that a correct diagnosis for undifferentiated neoplasm of nose and nasal sinuses was impossible to obtain by light microscopy only. Poorly differentiated olfactory neuroblastoma was also difficult to diagnose under electron microscope because the neurosecretory cytoplasmic granules were not easy to find and several hours would be required to search for them under electron microscope.

Adolescent↗
PubMed1991

Conventional and high resolution scanning electron microscopy of biological sectioned material.

Intracellular structures of embedded biological tissues (rat kidney, myocardium and small intestine) were observed by conventional-scanning electron microscopy (C-SEM) and high-resolution scanning electron microscopy (HR-SEM) after glass knife sectioning. C-SEM of semi-thin sections of material processed the same way as conventional transmission electron microscopy (TEM) provided strong backscattered electron (BSE)-dependent, two-dimensional secondary electron images (SEI(-)) which precisely integrated and further extended previous light microscopy (LM) observation of the same specimen. In addition, the three-dimensional (3-D) arrangement of intracellular organelles was appreciated using a mixture of acetone-soluble acrylic resin in place of epoxy resin embedding. Since the identification of such structures was hampered by the use of conventional fixations we introduced osmium maceration as a preliminary step to remove excess cytoplasmic matrix from the specimen. Consequently, semi-thin sections for LM and thin sections for TEM were obtained by sectioning of the tissue blocks. After resin removal, the sections were successfully observed in 3-D under a C-SEM. Finally, the deembedded, osmium treated sections proved to be smooth enough to facilitate deposition of continuous, ultra-thin (1 nm) chromium films and, therefore, HR-SEM studies of macromolecular cell membrane structures.

Animals↗
PubMedDate not supplied

[High resolution light microscopy: adaptation of the method and its use in the study of experimental leptospirosis in guinea pigs].

Morphological lesions in parenchimal and mesenchimal structures of liver and kidney were studied in guinea-pigs experimentally infected with Leptospira interrogans serogroup icterohaemorrhagiae in comparison with a group of non-infected guinea-pigs. All specimens were submitted to conventional light microscopy as well as to high resolution light microscopy, in one micrometer sections of tissue embedded in glycolmethacrylate. High resolution light microscopy, applied for the first time in leptospirosis, was proved very useful, since it enabled us to visualize cellular structures in the same slide used for panoramic view. Cell cohesion, brush borders, pynocytotic vesicles and organellae distributions were parameters especially suitable for analysis at this low-cost, highly precise procedure in microscopy.

Animals↗
PubMed1990

Video fluorescence microscopy as a tool for the study of cellular heterogeneity in epithelia.

The use of functional fluorescent dyes has allowed us to monitor intracellular pH in individually identified cells in renal epithelia. Using video microscopy we simultaneously measured the change in intracellular pH in several contiguous cells in response to various maneuvers. The video equipment included a silicon intensified target camera, a VHS videocassette recorder, a high resolution monochrome monitor, a video photometric analyzer and a 2-channel chart recorder. This equipment had a spatial resolution of 1 micron by light microscopy and a response time of less than 200 ms; it allowed us to perform double fluorescent labeling and obtain reliable measurements of intracellular pH, independent of gain, regardless of the location of the image on the screen. Using this video system we have shown that there is substantial heterogeneity in activity of H+/HCO3- transport pathways among adjacent cells in a monolayer of cells cultured from the rat renal inner medullary collecting duct. In isolated perfused rabbit renal cortical collecting ducts, video microscopy allowed us to show that there are two different types of intercalated cells: one that exhibits apical Cl-/HCO3- exchange and one that does not. Both show alkaline intracellular pH with respect to non-acid-base transporting epithelia. Video microscopy has several advantages over conventional microspectrophotometry. It provides rapid data acquisition along with increased sensitivity and the capacity for some subcellular analyses. One is able to analyze several individually identified cells during an experimental maneuver. The present video system was assembled for less than $15,000 and permits a more complete analysis of an epithelium than either single-cell photometry or spectrophotometric analysis of thousands of cells in suspension or monolayers.

Animals↗
PubMed1986

Review of urine microscopy for bacteriuria.

Urine microscopy for bacteriuria remains a useful and valid technique for the evaluation of urinary tract infection; however, established interpretive criteria are not agreed on. Our own data and a review of the literature demonstrate that reliable data can be obtained by enumerating the organisms observed in stained or unstained centrifuged and stained uncentrifuged urine specimens. Criteria are given for the interpretation of urine microscopy for maximum sensitivity and specificity for each method reviewed. For clinicians desiring to perform urine microscopy, we recommend the use of oil-immersion microscopy of Gram-stained centrifuged urine sediment and suggest that observing at least one organism per oil-immersion field corresponds with 95% sensitivity and that observing more than five organisms corresponds with 95% specificity for bacteriuria at a level of 10(5) or more colony-forming units per milliliter. Further testing will be required on any negative specimen from a symptomatic patient.

Bacteriological Techniques↗