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At least 847 records · Page 47Linked to original sources
PubMed2005

Maxillary sinus augmentation using a synthetic cell-binding peptide: a histologic and transmission electron microscopy case study in man.

PepGen P-15 is a combination natural anorganic bovine-derived hydroxyapatite matrix coupled with a synthetic cell-binding peptide (P-15). This material has improved bone formation in periodontal osseous defects and bone regenerative procedures. There were 3 specimens retrieved 18 months after a sinus lifting procedure using PepGen P-15. These specimens were treated to be observed under light microscopy and transmission electron microscopy. Light microscopy showed that most of the particles were surrounded by newly formed bone. In some areas, osteoid matrix was present. No acute inflammatory infiltrate was present. In transmission electron microscopy, all phases of bone formation (i.e., osteoid matrix, woven bone, and lamellar bone) were observed in the newly formed bone around the biomaterial particles. In some regions, this newly formed bone seemed to present interdigitations connecting to or entering into the particle surface. To our knowledge, this is the first report presenting data on transmission electron microscopy of PepGen P-15 used in a sinus augmentation procedure in man. Our results confirm previous reports on the clinical effectiveness of this material.

Alveolar Ridge Augmentation↗
PubMed1984

Comparison of microscopy, culture and enzyme immunoassay (Gonozyme) for the detection of Neisseria gonorrhoeae in urogenital specimens.

Urogenital specimens of male patients and female prostitutes were examined for gonorrhoea in a gonococcal antigen enzyme immunoassay (Gonozyme), by microscopic examination of stained smears and by bacterial culture. Out of 18 male patients, 14 showed positive reactions (all 14 by Gonozyme and by microscopy, but only eight by culture also). The sensitivity and specificity of Gonozyme was 100% in reference to microscopy. The predictive value for a positive test and for a negative test was 100%. The sensitivity of Gonozyme in reference to culture was also 100%, but the specificity was only 40%, because of the low yield of positive cultures. The predictive value for a positive test was 57% and for a negative test 100%. Out of 189 female prostitutes, 41 (22%) had a positive reaction in at least one test (Gonozyme, microscopy and culture were positive in 10; Gonozyme and culture in three; Gonozyme and microscopy in 14; Gonozyme alone in 11; culture alone in three). The sensitivity of Gonozyme was 100% and specificity 92% in reference to microscopy. The predictive value for a positive test was 63% and for a negative test 100%. In reference to culture, the sensitivity was 81% and specificity 86%. The predictive value for a positive test was 34% and for a negative test 98%. In prostitutes, the rate of asymptomatic infections was 14%, if one assumed that all Gonozyme-positive results were truly positive. Gonozyme proved to be the most sensitive method for screening female patients. To discriminate possibly false positive reactions, Gonozyme-positive specimens should be corroborated, preferably by bacterial cultivation.

Antigens, Bacterial↗
PubMed2003

Fluorescent resolution target for super-resolution microscopy.

Historically, resolution in fluorescence optical microscopy has been limited by the Rayleigh criterion. Recently, however, several techniques have achieved resolution below that specified by the Rayleigh criterion. Among these are 4-Pi confocal microscopy, harmonic excitation light-microscopy, stimulated emission depletion microscopy, near-field scanning optical microscopy and I(5)M. The most widely accepted current method of resolution testing is to image an array of closely packed fluorescent beads or beads dispersed in a matrix. This shows that the system is capable of resolving a feature with a given diameter; however, it does not demonstrate the classical resolution of the system. We have fabricated a fluorescent resolution target for better characterization of a system's resolution.

Fluorescent Dyes↗
PubMed2004

Use of ex vivo confocal scanning laser microscopy during Mohs surgery for nonmelanoma skin cancers.

BACKGROUND: Ex vivo confocal scanning laser microscopy offers rapid optical reflectance imaging of excised tissue without conventional frozen histopathology that can potentially expedite Mohs surgery. OBJECTIVE: The objective was to determine the feasibility of using ex vivo confocal scanning laser microscopy during Mohs surgery for detecting residual basal cell carcinoma and squamous cell carcinoma. METHODS: One-hundred fifteen Stage I Mohs surgery excisions (92 basal cell carcinoma, 23 squamous cell carcinoma) were imaged with acetowhitening and confocal scanning laser microscopy and compared to conventional Mohs frozen histologic sections for normal and tumor features. RESULTS: Large aggregates of residual tumor such as nodular basal cell carcinoma were easily detected by ex vivo confocal scanning laser microscopy, whereas smaller tumor foci were not consistently identified. Confocal morphology of tumor subtypes is described. CONCLUSION: Ex vivo confocal scanning laser microscopy can potentially expedite Mohs surgery in rapidly detecting large nodular basal cell carcinomas without conventional frozen histopathology. Further improvements in instrumentation and image quality are necessary to allow broader application and acceptance of this novel technology in Mohs surgery.

Boston↗
PubMed2006

Corneal optics after reading, microscopy and computer work.

PURPOSE: To compare lid-induced changes in corneal optics following reading, microscopy and computer work. METHODS: Nine subjects with normal ocular health were recruited for the study. Five subjects were myopic, two were emmetropic, one was astigmatic and one was hyperopic. Corneal topography was measured before and after 60 mins of reading a novel, performing a blood cell counting task on a microscope and Internet searching. Corneal topography data were used to derive the corneal wavefront Zernike coefficients up to the fourth order. A meridian analysis of instantaneous corneal power along the upper 90-degree semi-meridian was performed to examine local changes caused by eyelid pressure. Digital photography was used to capture body posture and eyelid position during the tasks. RESULTS: Each of the three tasks showed systematically different effects on both the characteristics and location of corneal topography changes. Reading and microscopy generally exhibited larger and more centrally located changes compared with the computer task. Differences in wavefront aberration characteristics between the three tasks were apparent in both lower and higher order aberrations. The location of corneal distortions differed significantly between microscopy and computer work, with microscopy causing distortions to occur closer to the videokeratoscope measurement axis compared with computer work (p = 0.015). CONCLUSIONS: Reading, microscopy and computer work have different effects on corneal aberrations. The results are in agreement with the hypothesis that lid-induced corneal aberrations may play a role in myopia development.

Adult↗
PubMed1981

A study of the value of resin-embedded semi-thin sections and electron microscopy in the diagnosis of renal biopsies.

Two hundred consecutive renal biopsies originally studied by light microscopy of paraffin- and semi-thin sections and electron microscopy were reviewed and re-classified according to the proposed WHO classification for glomerular disease. The accuracy of diagnoses based on paraffin sections alone, and of those based on paraffin- and semi-thin sections were compared with the results of the final evaluation, when electron microscopy also was taken into account. Paraffin material showed a diagnostic accuracy of 59 per cent for glomerulonephritis, and 82 per cent for other renal diseases. The diagnostic accuracy of semi-thin sections was 61 per cent for glomerulonephritis and 76 per cent for other renal diseases; i.e. not improved. It is concluded that the study of semi-thin sections cannot replace electron microscopy in the diagnoses of renal biopsies. In the present study, electron microscopy altered the diagnoses in 34 per cent and yielded additional useful information in another 45 per cent of patients with glomerulonephritis. Therefore, the electron microscope should be employed routinely in the study of renal biopsies from this group of patients.

Biopsy, Needle↗
PubMed1994

Electron cryo-microscopy of vitrified biological specimens: towards high spatial and temporal resolution.

A decade after the development of electron cryo-microscopy for vitrified specimens, its advantages and limitations are analysed. Indeed, recent work carried out by different laboratories strengthens the idea that electron cryo-microscopy might soon be an alternative method to X-ray crystallography and NMR techniques for determining the structure of biological assemblies with both high spatial and temporal resolutions. High pressure freezing allows vitrification of larger volumes of biological suspensions. Thick vitrified objects can be cryosectioned. Electron cryo-microscopy of the sections gives images having a resolution better than 2 nm. Although the high resolution imaging mode under low dose conditions is not yet fully understood, microscopes are being developed to provide better and better images. Image averaging is being facilitated by the development of both crystallization and computer methods. Thus, we can expect that electron microscopy will soon become a potential technique for structural determination at atomic resolution. Finally, much effort is being devoted to improving the temporal resolution of electron cryo-microscopy. Soon, we may be able to observe molecules during their biological activity.

Biopolymers↗
PubMed2001

Spatially modulated illumination microscopy: online visualization of intensity distribution and prediction of nanometer precision of axial distance measurements by computer simulations.

During the last years, measurements considerably beyond the conventional "Abbe-Limit" of optical resolution in far field light microscopy were realized by several light microscopical approaches. Point spread function (PSF) engineering, spectral precision distance microscopy (SPDM), and related methods were used to demonstrate the feasibility of such measurements. SPDM allows the measurement of position and multiple distances between point-like fluorescent objects of different spectral signatures far below the optical resolution criterion as defined by the full width at half maximum of the PSF. Here, we report a software method to obtain online visualization of light distribution in the lateral and axial direction of any object detected in a spatially modulated illumination (SMI) microscope. This strongly facilitates routine application of SMI microscopy. The software was developed using Microsoft Visual C++ running on Windows NT. Furthermore, some aspects of the theoretical limits of the SPDM method were studied by virtual microscopy. For the case of SMI microscopy the precision of axial distance measurements was studied, taking into account photon statistics and image analysis procedures. The results indicate that even under low fluorescence intensity conditions typical for biological structure research, precise distance measurements in the nanometer range can be determined, and that axial distances in the order of 40 nm are detectable with such precision.

Computer Simulation↗
PubMed1990

Sensitive solid-phase immune electron microscopy double-antibody technique with gold-immunoglobulin G complexes for detecting rotavirus in cell culture and feces.

A new solid-phase immune electron microscopy double-antibody colloidal-gold technique (SPIEMDAGT) was developed and compared with direct electron microscopy, direct immune electron microscopy, and enzyme immunoassay for detecting rotavirus. Guinea pig and rabbit antirotavirus antisera were used as capture and detector antibodies, respectively, and goat anti-rabbit immunoglobulin G-gold complexes were employed as a label. Animal rotavirus in cell culture media and human virus in stool specimens were detected by this method. On average, SPIEMDAGT detected 800 times more virus particles than direct electron microscopy and 45 times more particles than direct immune electron microscopy and yielded 20% more positives than enzyme immunoassay. SPIEMDAGT could detect not only viral antigen associated with morphologically recognizable particles but also antigen present when whole virus particles were not visible.

Antibodies, Viral↗
PubMed2002

Comparison of two commercial assays with expert microscopy for confirmation of symptomatically diagnosed malaria.

Conventional light microscopy has been the established method for malaria diagnosis. However, recently several nonmicroscopic rapid diagnostic tests have been developed for situations in which reliable microscopy may not be available. This study was conducted to evaluate the diagnostic performance of a recently introduced ICT Malaria Pf/Pv test. This assay detects Plasmodium falciparum histidine-rich protein 2 antigen (PfHRP-2) for P. falciparum diagnosis and pan-malarial antigen for P. vivax diagnosis. In this study we compared the performance of ICT Malaria Pf/Pv with microscopy of Giemsa-stained blood films and with an OptiMAL test that detects Plasmodium lactate dehydrogenase (pLDH) antigen. A total of 750 clinically suspected malaria patients were examined at local health centers in Kuwait. Both the antigen tests had a high degree of specificity (>98%) for detection of malaria infection. However, they were less sensitive than microscopy. Compared with microscopy the ICT Malaria PF/pf test failed to detect malaria infection in 93 (34%) of 271 malaria patients (11% of patients with P. falciparum and 37% of patients with P. vivax) and the OptiMAL test failed to detect malaria infection in 41 (15%) of 271 malaria patients (7% of patients with P. falciparum and 13% of patients with P. vivax). The sensitivities of the ICT Malaria Pf/Pv and OptiMAL tests for detection of P. falciparum infection were 81 and 87%, and those for detecting P. vivax were 58 to 79%, respectively. The sensitivity of the ICT Malaria Pf/Pv and OptiMAL tests decreased significantly to 23 and 44%, respectively, at parasite densities of <500/ micro l. Both of the tests also produced a number of false-positive results. Overall, the performance of the OptiMAL test was better than that of the ICT Malaria Pf/Pv test. However, our results raise particular concern over the sensitivity of the ICT Malaria Pf/Pv test for detection of P. vivax infection. Further developments appear necessary to improve the performance of the ICT Malaria Pf/Pv test.

Animals↗
PubMed2005

Novel multipurpose methodology for detection of mycobacteria in pulmonary and extrapulmonary specimens by smear microscopy, culture, and PCR.

A novel, robust, reproducible, and multipurpose universal sample processing (USP) methodology for highly sensitive smear microscopy, culturing on solid and liquid media, and inhibition-free PCR which is suitable for the laboratory diagnosis of both pulmonary and extrapulmonary tuberculosis (TB) has been developed. This method exploits the chaotropic properties of guanidinium hydrochloride for sample processing and involves incubating the specimen with USP solution, concentrating bacilli by centrifugation, and using the processed specimen for smear microscopy, culture, and PCR. The detection limit for acid-fast bacilli in spiked sputum by smear microscopy is approximately 300 bacilli per ml of specimen. USP solution-treated specimens are fully compatible with culturing on solid and liquid media. High-quality, PCR-amplifiable mycobacterial DNA can be isolated from all types of clinical specimens processed with USP solution. The method has been extensively validated with both pulmonary and extrapulmonary specimens. Furthermore, the USP method is also compatible with smear microscopy, culture, and PCR of mycobacteria other than tubercle bacilli. In summary, the USP method provides smear microscopy, culture, and nucleic acid amplification technologies with a single sample-processing platform and, to the best of our knowledge, is the only method of its kind described to date. It is expected to be useful for the laboratory diagnosis of TB and other mycobacterial diseases by conventional and modern methods.

Bacteriological Techniques↗
PubMed1984

Detection of early neoplastic changes in experimentally induced colorectal cancer using scanning electron microscopy and cell kinetic studies.

Colonic tumours were induced in Wistar rats using 12 consecutive subcutaneous injections of azoxymethane at a dose of 10 mg/kg/week. Pairs of rats were killed at five weekly intervals after initial injection until 25 weeks. Colonic mucosa was sampled from five standard areas along the length of the colon and examined by both scanning electron microscopy and conventional light microscopy. The crypt cell production rate was measured by stathmokinetic techniques. Scanning electron microscopy showed microadenomas as early as five weeks and consistently after 15 weeks. They were found predominantly in the distal colon and increased in size with time. The lesions showed a progressive increase in the number of crypts per adenoma and increasingly disorganised slit shaped crypt orifices. The presence of epithelial dysplasia in the microadenomas and of invasion of the colonic wall by carcinoma was confirmed histologically, although fewer lesions were identified in tissue sections than by scanning electron microscopy. Crypt cell production rate increased with time, particularly in the distal colon. This increase was significant between five and 25 weeks. The results of these observations suggest that there is an adenoma-carcinoma sequence in this animal model. The value of scanning electron microscopy in identifying and quantifying the mucosal changes during carcinogenesis is emphasised.

Adenoma↗
PubMed1980

Electron microscopy as an aid to the rapid diagnosis of virus diseases of veterinary importance.

The use of electron microscopy to assist in the rapid diagnosis of virus diseases of veterinary importance is reviewed. Electron microscopy can be used to assist the laboratory diagnosis of a virus disease at two stages during the investigation; either by demonstrating virus in clinical material or by identifying isolates from tissue culture or similar systems. Direct electron microscopy and immunoelectron microscopy are particularly useful for rapid diagnosis. The advantages of electron microscopy lie in speed and flexibility, and the disadvantages in the high particle concentration needed and the presumptive nature of a diagnosis.

Animals↗
PubMed2001

Dilated intercellular spaces as markers of reflux disease: histology, semiquantitative score and morphometry upon light microscopy.

BACKGROUND AND AIMS: A recent electron microscopy study suggested that dilated intercellular spaces (DIS) are specific for acid reflux-damaged esophageal epithelium. Electron microscopy is, however, expensive and difficult to apply to routine biopsies. The aims of this study are to establish a method for assessing DIS on light microscopy of esophageal biopsies and to estimate its association with current clinicopathological parameters of esophagitis. MATERIALS AND METHODS: 21 patients with reflux symptoms were investigated. Light microscopy biopsies were assessed for DIS size by a semiquantitative method and computer-assisted, static morphometry. A DIS score accounting for DIS size and distribution was assigned to each patient and its association with 30 clinicopathological variables investigated by univariate and multivariate logistic regression. RESULTS: Both the semiquantitative method and static morphometry identified 4 different classes of DIS size. The DIS score was significantly and independently associated with the esophageal symptoms score, the histological score of esophagitis and the relevant morphometry data. CONCLUSIONS: DIS may be efficiently assessed during light microscopy of routine esophageal biopsies. Since correlation with both the histology and the symptoms of esophagitis, the DIS score may be considered a novel parameter of esophagitis and is suggested for the routine evaluation of esophageal biopsies in patients with reflux disease.

Adult↗
PubMed2001

Applications of fluorescence microscopy to studies of dental hard tissue.

In this review we describe applications of fluorescence microscopy to investigations of dental hard tissue. Many studies have shown that human teeth show autofluorescence and several applications of fluorescence microscopy have been reported, although the chemical nature of autofluorescence remains unknown. However, most applications are based on a static measurement mode, which has inherent limitations. These limitations can be overcome by the use of time-resolved fluorescence microscopy. Therefore, we attempted to combine ordinary and time-resolved fluorescence microscopy to study human dentine. Using stationary measurements, blue fluorescence with a peak of 440 +/- 10 nm and a width of approximately 100 nm was observed. Increases in fluorescence intensity were found to be dependent upon age and temperature, regardless of tooth type or gender. The results suggest that the aging mechanism for crown dentine differs from that for root dentine and that the observed increase in fluorescence intensity is partially due to a temperature-dependent physicochemical mechanism. We speculate that fluorescence microscopy will become a useful tool for analysis of dental hard tissue in several fields.

Aging↗
PubMed2003

Ultrathin cryosections: an important tool for immunofluorescence and correlative microscopy.

Here we show that ultrathin cryosections of placental tissue can be used as a substrate in immunofluorescence experiments. A high degree of spatial resolution can be achieved in these preparations because there is essentially no out-of-focus fluorescence. Therefore, immunofluorescence microscopy using ultrathin cryosections provides a very useful method for determining the precise subcellular localization of antigens in tissues. In addition, ultrathin cryosections of placenta also serve as a substrate for correlative immunofluorescence and immunoelectron microscopy using FluoroNanogold as the detection system. In correlative microscopy, the exact same structures in the same ultrathin section were observed by both fluorescence and electron microscopy. Using a particle counting procedure and electron microscopy, we compared the labeling obtained with colloidal gold and FluoroNanogold and found a higher number of particles with silver-enhanced FluoroNanogold than with colloidal gold.

Animals↗
PubMed1986

Comparative analysis of surface membrane immunoglobulin determination by flow cytometry and fluorescence microscopy.

The analysis of membrane surface immunoglobulin (SmIg) on B lymphocytes was carried out in 59 normal individuals and nine patients with B-cell non-Hodgkin's lymphomas by conventional immunofluorescence microscopy and flow cytometry. Five channel settings of a cytofluorograph were evaluated (100, 150, 200, 250, 300) and the mean and standard deviation of the percent positive cells were calculated and compared to the mean and standard deviation of the microscope reading. On the basis of the relative fluorescence reactivity, we were able to determine a fluorescence intensity at which the results of flow cytometry and fluorescence microscopy were comparable. In normal individuals, for cells expressing surface Ia, the channel giving similar results to that of fluorescence microscopy was 150; for kappa and lambda chains, channel 200; for Fab'PV, channel 200; and for IgM, channel 250. In patients with B-cell non-Hodgkin's lymphomas, for cells expressing surface Ia the channel giving similar results to that of fluorescence microscopy was 100; for kappa, channel 100; for lambda, channel 200; for Fab'FV, channel 150; and for IgM, channel 150. Flow cytometric analysis of SmIg appears to be superior to fluorescence microscopy in efficiency, and has the added advantages of being a rapid, sensitive, and objectively quantitative methodology.

B-Lymphocytes↗
PubMed1991

Gap junction distribution in adult mammalian myocardium revealed by an anti-peptide antibody and laser scanning confocal microscopy.

A polyclonal antiserum, raised against a synthetic peptide matching part of the sequence of connexin43 (a rat cardiac gap-junctional protein), was used in combination with laser scanning confocal microscopy to investigate gap junction distribution in cardiac tissues from a range of mammalian species. Comparison of the localised punctate staining patterns obtained in ventricular tissue with the distribution of intercalated disks as viewed by conventional light microscopy and electron microscopy, and with the staining observed by standard light-microscope immunofluorescence using the same anti-serum, demonstrated highly specific labelling of clearly resolved individual gap junctions. Laser scanning confocal microscopy of ventricular myocardium showed the immunostained gap junctions to be confined to well-defined intercalated disks bisecting the long axis of the muscle fibre, whereas in the atrial myocardium, gap junctions were commonly distributed widely over the lateral surfaces of the myocyte body. Rat atrial gap junctions were significantly larger (as measured by the longest axial lengths of fluorescent spots), and showed a narrower spread of sizes, than their counterparts in the ventricle. Ventricular myocardium from six mammalian species including man gave similar immunostaining patterns, indicating conservation both of the epitope(s) detected by the antiserum, and of the general organisation of the cell-to-cell pathways for electrical propagation, in the mammalian heart. Optical section series obtained by laser scanning confocal microscopy permitted the quantification and mapping of the three-dimensional distribution of gap junctions in ventricular intercalated disks with high clarity over substantial specimen depths. A consistent feature of gap junction organisation within disks of ventricular myocardium in all species studied was the presence of a conspicuous ring of large gap junctions around the periphery of the disk. Immunostained gap junctions lying within the interior zone delineated by the peripheral junctions generally occurred at lower numerical densities and were significantly smaller. In all species, less than 3% of all immunolabelled gap junctions measured were greater than 2 microns in maximal length, though a small proportion (0.06%) exceeded 4 microns. The numerical density of immunolabelled gap junctions in the disk was similar between species; however, within species there was a significant decrease in numerical density with increasing disk size. The new features of intercalated disk structure revealed in this study may have an important part to play in the intercellular communication and electrical propagation properties of the mammalian heart.

Analysis of Variance↗