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At least 865 records · Page 48Linked to original sources
PubMed2004

Enhanced accuracy and reliability of HER-2/neu immunohistochemical scoring using digital microscopy.

We evaluated the HER-2/neu status of 129 invasive breast cancer specimens for gene amplification by fluorescence in situ hybridization (FISH) and protein overexpression by immunohistochemical analysis. Each immunohistochemically stained slide was interpreted on a standard microscope independently by 10 pathologists. Separately, each pathologist reviewed the same slide set with the assistance of digital microscopy. A total of 1,258 manual immunohistochemical scores and 1,269 digital microscopy immunohistochemical scores were completed. When the same 10 pathologists scored the same immunohistochemical slides with the assistance of digital microscopy, each reviewer improved concordance with FISH, and overall concordance with immunohistochemical analysis improved significantly, to 93% (P < .001). The interrater kappa was used to compare interobserver agreement in HER-2 immunohistochemical scoring for manual and digital microscopy interpretation. Significant improvement in interobserver agreement (kappa = 0.51 vs 0.86; P < .001) was achieved when HER-2 immunohistochemical analysis was scored with the assistance of the digital microscope. The assistance of digital microscopy improves the accuracy and reliability of HER-2 immunohistochemical analysis. These data suggest that documented discrepancies between HER-2 immunohistochemical analysis and FISH reflect predominantly errors in manual immunohistochemical interpretation as opposed to immunohistochemical reagent limitations.

Breast Neoplasms↗
PubMed2006

Correlative microscopy of ultrathin cryosections in placental research.

In this chapter, we describe procedures for correlative microscopy in immunocytochemical studies on the human placenta. We have adapted ultrathin cryosections for use in high-resolution immunofluorescence microscopy (IFM) and for correlative immunocytochemical localization using fluorescence and electron microscopy. High-resolution IFM of ultrathin cryosections (50-100 nm in thickness) can be important because these physical sections minimize the potential for false co-localization in the z-dimension. In addition, IFM of these sections affords greater sampling efficiency than does immunoelectron microscopy (IEM). These ultrathin cryosections are compatible with conventional electron microscopy because a relatively low-voltage electron beam can penetrate them. Thus, the same ultrathin cryosections of placenta can be viewed in both fluorescence and electron microscopes. This latter point can be of importance because it may be necessary to know the true size and shape of objects observed by IFM; this can be determined best by IEM. Additionally, IEM can provide the "reference space" lacking in IFM. The use of ultrathin cryosections is a powerful approach for placental research, especially for the investigation of the in situ localization of antigens in the complex structure of the human placenta.

Caveolin 1↗
PubMed1999

Automation of urine sediment examination: a comparison of the Sysmex UF-100 automated flow cytometer with routine manual diagnosis (microscopy, test strips, and bacterial culture).

Urine specimens from 438 patients were examined with the UF-100 flow cytometer (Sysmex TOA Medical Electronics (Europe) GmbH, Hamburg, Germany) and by manual microscopy and test strips. One hundred and forty-two of these were also examined bacteriologically. The measurements with the UF-100 were performed on native urine without prior centrifugation. Intraassay imprecision, CV of 1.3% (547/microliter) to 8.5% (24/microliter) for erythrocytes and CV of 2.4% (218/microliter) to 5.6% (10/microliter) for leukocytes, are similar to those usual in clinical chemistry, and are very much better than those seen in manual microscopy of sediment. In routine use, overloading the flow cytometer by an excessive concentration of particles was observed in 9% of specimens. Such specimens should be checked visually. The UF-100 is distinctly more sensitive than manual microscopy for determining leukocytes, erythrocytes, epithelial cells and bacteria. Reference ranges were estimated from the results obtained. These enabled the UF-100 to replace routine manual diagnostic methods. Although the sensitivity is improved over manual microscopy of sediment, it is always necessary to perform parallel test strip examination when determining erythrocytes in order to detect haemolysis. In our opinion the Sysmex UF-100 is a suitable replacement for manual microscopy of urine sediment. In addition it offers an opportunity to improve standardization of basic urinalysis.

Automation↗
PubMed2000

Optical aberrations and objective choice in multicolor confocal microscopy.

Refinements in design have simplified confocal microscopy to the extent that it has become a standard research tool in cell biology. However, as confocal microscopes have become more powerful, they have also become more demanding of their optical components. In fact, optical aberrations that cause subtle defects in image quality in wide-field microscopy can have devastating effects in confocal microscopy. Unfortunately, the exacting optical requirements of confocal microscopy are often hidden by the optical system that guarantees a sharp image, even when the microscope is performing poorly. Optics manufacturers provide a wide range of microscope objectives, each designed for specific applications. This report demonstrates how the trade-offs involved in objective design can affect confocal microscopy.

Animals↗
PubMed1981

Electron microscopy in surgical pathology: a selective review.

The high resolution provided by electron microscopy can contribute to histomorphological diagnosis by allowing the detection of structures which are invisible to the light microscope. These structures include characteristic nuclear or cytoplasmic contours, intercellular attachments and intracellular components. The recognition of such features may allow specific diagnosis in lesions which cannot be precisely categorized by light microscopy. Electron microscopy is particularly useful for the diagnosis of neoplasms. This review describes some of the characteristic morphological features which can be demonstrated in neoplastic cells by electron microscopy and briefly considers several areas where the technique is of special value. Electron microscopy is now an integral part of the diagnostic process in surgical pathology and can be regarded as a routine technique rather than a special procedure to be delegated to others.

Adenocarcinoma↗
PubMed2003

Electron microscopy for rapid diagnosis of infectious agents in emergent situations.

Diagnostic electron microscopy has two advantages over enzyme-linked immunosorbent assay and nucleic acid amplification tests. After a simple and fast negative stain preparation, the undirected, "open view" of electron microscopy allows rapid morphologic identification and differential diagnosis of different agents contained in the specimen. Details for efficient sample collection, preparation, and particle enrichment are given. Applications of diagnostic electron microscopy in clinically or epidemiologically critical situations as well as in bioterrorist events are discussed. Electron microscopy can be applied to many body samples and can also hasten routine cell culture diagnosis. To exploit the potential of diagnostic electron microscopy fully, it should be quality controlled, applied as a frontline method, and be coordinated and run in parallel with other diagnostic techniques.

Communicable Diseases, Emerging↗
PubMed1999

Confocal microscopy in biomedical research.

Confocal microscopy has allowed a major advance in biological imaging, since it represents a rapid, cost effective means of ecamining thick tissue specimens. In most cases, this involves fluorescence imaging and it is increasingly being used as a basic tool in biomedical research. Confocal microscopy allows the collection of thin optical sections, without the need for physical sectioning of the tissue. Additionally, confocal microscopes can usually produce images with greater sensitivity, contrast and resolution than those produced with normal light microscopes. We attempt to explain how this technology might be better used as a routine research tool. Since high quality, in-focus optical sections of thick tissue preparations can be generated quickly, confocal microscopy, in combination with immunofluorescence histochemistry, can now be used to examine complex three-dimensional distributions of distinct structures within tissues such as nerves within airways. Additionally, ultraviolet confocal microscopy allows the assessment of both dynamic and static phenomena in living cells and tissues. Thus, in addition to the imaging of fluorescence associated with structural elements, confocal microscopes can be used to quantitatively evaluate the distribution and fluxes of intracellular ions like calcium. Rapid, line-scanning confocal microscopes can be used in the assessment of dynamic events. For example, the in vivo imaging of microvascular permeability in airways becomes possible for the first time. By providing examples of some of our uses for confocal microscopy, we might encourage others to explore this relatively new and important texhnology for examining events and structures in single cells, tissue samples and in intact animals.

Animals↗
PubMed2001

Improved method of direct microscopy for detection of acid-fast bacilli in sputum.

Microscopy of direct smears for acid-fast bacilli (AFB) is the most commonly used method for diagnosis of tuberculosis. However, direct microscopy of sputum, though rapid, has low sensitivity and there is a need for improved methods. Sputum samples were collected from patients attending the Union Tuberculosis Institute, Yangon. The microscopy of smears made directly from sputum were compared with the microscopy after liquefaction of sputum with household bleach (NaOCl) and concentration of bacteria by centrifugation. Out of 948 samples, 248 samples (26.2%) were positive for acid-fast bacilli by direct microscopy and 293 samples (30.9%) were positive for acid-fast bacilli by the household bleach method. There was a significant increase in the number of acid-fast bacilli positive samples by the house-hold bleach method (p<0.05). The method is simple and cheap. As a disinfectant, household bleach has the advantage of lowering the risk of laboratory infection.

Centrifugation↗
PubMed2001

[Contribution of radiography and repeat microscopy in the diagnosis of pulmonary tuberculosis in the hospital environment of Bamako].

WHO and IUAT-LD recommend repeated microscopy in order to improve the detection of contagious cases of pulmonary tuberculosis. Our aim was to determine the contributions of radiology and microscopy in the diagnosis of pulmonary tuberculosis. From January 1998 to April 1999 radiography and microscopy were performed for 275 patients who were admitted to the pneumology service. Pulmonary tuberculosis prevalence was higher among women aged 10 to 29 years than among men of the same age (p = 10(-6)). 188 (68.4%) women tested positive, 49 (17.8%) tested positive at the second microscopy and 1 (0.36%) at the the third. The main radiological lesions were nodules + infiltrats (46.2%), nodules + infiltrats + cavity (26.2%) and infiltrats + cavity (6.5%). Repeated microscopy significantly increased the proportion of pulmonary tuberculosis cases detected (from a prevalence 68.4% to 86.5%).

Adolescent↗
PubMed2003

[A powerful tool for study of sperm--soft X-ray microscopy].

Soft X-ray microscopy is a microimaging technique using soft X-ray as illuminative source. It fills the gap between optical and electron microscopy. Soft X-ray microscopes have better resolution than visible microscopes. In comparison with electron microscopes, it can examine thick (up to 10 micrometers for biological samples) and wet specimens in their natural states without being dehydrated, sectioned and stained. In addition, soft X-ray microscopy can map elements and analyze the biological macromolecules such as protein and DNA in the examined samples. In this paper, the advantages of soft X-ray microscopy for biology are briefly described. The applications of soft X-ray microscopy to the analysis of mammal and human sperm are illustrated.

Animals↗
PubMed1992

Human performance studies of the video microscopy component of a dynamic telepathology system.

Human performance studies were performed to evaluate the video microscopy component of a proposed dynamic telepathology system. Frozen sections from breast biopsies of 115 patients were evaluated by both conventional light microscopy and video microscopy by 6 pathologists. Receiver operator characteristic (ROC) curve studies showed nearly identical levels of discrimination between benign and malignant breast lesions for both viewing modalities. Viewing times were significantly greater (p < 0.001) for video microscopy but within a time frame that rendered the technology of potential value for pathology diagnostic applications. Large degrees of interobserver viewing time variability were found for light and video microscopy.

Biopsy↗
PubMed2005

Structural evidence for alpha-synuclein fibrils using in situ atomic force microscopy.

Human alpha-synuclein is a presynaptic terminal protein and can form insoluble fibrils that are believed to play an important role in the pathogenesis of several neurodegenerative diseases such as Parkinson's disease, dementia with Lewy bodies and Lewy body variant of Alzheimer's disease. In this paper, in situ atomic force microscopy has been used to study the structural properties of alpha-synuclein fibrils in solution using two different atomic force microscopy imaging modes: tapping mode and contact mode. In the in situ contact mode atomic force microscopy experiments alpha-synuclein fibrils quickly broke into fragments, and a similar phenomenon was found using tapping mode atomic force microscopy in which alpha-synuclein fibrils were incubated with guanidine hydrochloride (0.6 M). The alpha-synuclein fibrils kept their original filamentous topography for over 1 h in the in situ tapping mode atomic force microscopy experiments. The present results provide indirect evidence on how beta-sheets assemble into alpha-synuclein fibrils on a nanometer scale.

Guanidine↗
PubMed2005

Application of lot sampling of sputum AFB smears for the assessment of microscopy centres.

SETTING: Designated microscopy centres (DMC) and additional microscopy centres (AMC) performing sputum acid-fast bacilli (AFB) microscopy, the District TB Centre (DTC) and a reference laboratory (RL). OBJECTIVES: To ascertain the feasibility of adopting lot sampling of AFB smears and to assess the performance of MCs employing Senior Tuberculosis Laboratory Supervisors (STLS) with no knowledge about the principles of quality assurance of AFB microscopy and RL-based laboratory technicians with training on quality assurance for blinded checking of AFB smears. METHODS: Slides from MCs were transported to the DTC and the RL; 20 smears per month per MC were selected systematically; 1547 slides from DMCs and 726 from AMCs were checked, respectively, by STLSs at the DTC and by RL laboratory technicians. Discrepancies were resolved by referee. RESULTS: The discrepancy between MC laboratory technicians and STLSs at the DTC was 4.7%, compared to 1% at the RL. The STLSs and RL-based laboratory technicians had 70 and 2 errors, respectively. CONCLUSIONS: Lot sampling of AFB smears is feasible under field conditions. Assessment of MCs was more valid with RL-based technicians trained in principles of quality assurance of sputum AFB microscopy than with STLSs with no such training and working in the field.

Bacteriological Techniques↗
PubMed2005

Quality of sputum smear microscopy in Taiwan.

BACKGROUND AND PURPOSE: Four mycobacteriology laboratories in northern Taiwan collected slides from their routine work for an international training course on quality assurance of sputum smear microscopy held from 19-27 August 2004 in Taipei. Rechecking of a random sample of these slides provided an opportunity to evaluate the quality of sputum smear microscopy in the collaborating laboratories. METHODS: Participants used a systematic sampling method to choose 100 to 120 slides from a set of 600 to 800 slides for evaluating the quality of smear and rechecking. Recheckers were blinded to the microscopy results reported by the testing laboratories. Discordant slides were re-examined by a second rechecker in order to make the final decision. RESULTS: A total of 433 slides were evaluated for smear quality. Of these 433 slides, 177 (41%) had proper smear size, 194 (45%) proper thickness and 212 (49%) proper staining. Rechecking of slides revealed that 2 of 4 laboratories had at least 1 high false-negative and 3 of 4 laboratories had at least 1 low false-negative result. CONCLUSIONS: We conclude that: 1) the 2 laboratories with high false-negative results need a supervisory visit in order to determine the causes; and 2) the national tuberculosis program should direct more attention to the quality of sputum smear microscopy and develop a formal plan for external quality assessment of sputum smear microscopy in Taiwan.

Cytodiagnosis↗
PubMed2006

Diagnosis of malaria by magnetic deposition microscopy.

Although malaria contributes to a significant public health burden, malaria diagnosis relies heavily on either non-specific clinical symptoms or blood smear microscopy methods developed in the 1930s. These approaches severely misrepresent the number of infected individuals and the reservoir of parasites in malaria-endemic communities and undermine efforts to control disease. Limitations of conventional microscopy-based diagnosis center on time required to examine slides, time required to attain expertise sufficient to diagnose infection accurately, and attrition from the limited number of existing malaria microscopy experts. Earlier studies described magnetic properties of Plasmodium falciparum but did not refine methods to diagnosis infection by all four human malaria parasite species. Here, following specific technical procedures, we show that it is possible to concentrate all four human malaria parasite species, at least 40-fold, on microscope slides using very inexpensive magnets through an approach termed magnetic deposition microscopy. This approach delivered greater sensitivity than a thick smear preparation while maintaining the clarity of a thin smear to simplify species-specific diagnosis. Because the magnetic force necessary to concentrate parasites on the slide is focused at a precise position relative to the magnet surface, it is possible to examine a specific region of the slide for parasitized cells and avoid the time-consuming process of scanning the entire slide surface. These results provide insight regarding new strategies for performing malaria blood smear microscopy.

Animals↗
PubMed1990

[Predictive value of electron microscopy studies in virological diagnosis].

The negative staining techniques in transmission electron microscopy have been used as a routine tool in viral diagnosis since 30 years. In a short review, different preparation techniques, fields of application, advantages and disadvantages of electron microscopy in rapid diagnostic are discussed. The application of electron microscopy depends on availability of other more effective methods. Some viruses, specially in faecal samples, are identifiable only by electron microscopy till now. Sensitivity and specificity are improved by immune electron microscopy comprising suspension, immunosorbent and immunogold techniques. Using rapid embedding techniques, ultrahistology is a valuable tool in identifying viruses in biopsy samples, too.

Histological Techniques↗
PubMedDate not supplied

[Synovial fluid crystal identification by electron microscopy].

BACKGROUND: In clinical practice crystal identification in synovial fluid is made by polarized light microscopy and with some specific stainings. Nevertheless, sometimes we are unable to identify crystals by these means, either because they are too small or because they are widespread on the fluid. AIMS: To compare the identification of crystals in synovial fluid from patients with non-infectious monoarthritis but no history of local trauma or articular disease, using polarized light and electronic microscopy. METHODS: We analized synovial fluid samples from patients with non-infectious monoarthritis and no history of local trauma or articular disease. First we used a polarized light microscope and alizarin red staining. Later we used conventional transmission electron microscopy and energy dispersive spectroscopy, in order to identify and characterize crystals. RESULTS: Fourty-five samples from 23 synovial fluids were analyzed. Under polarized light microscopy we identified crystals on 11 samples: 3 with calcium pyrophosphate crystals, 6 with calcium basic phosphate crystals and 2 with sodium monourate crystals. On the remaining 12 samples we were unable to identify crystals. Samples were then analyzed by conventional transmission electron microscopy and energy dispersive spectroscopy confirming the presence of the previously identified crystals. On the remainig 12 samples we were able to identify calcium basic phosphate crystals. DISCUSSION: Microcrystals seem to be an universal finding in synovial fluid of patients with osteoarthritis. The prevention of their deposition in joints might contribute to stop joint damage in this disease.

Arthritis↗
PubMed1985

Relationship of Mallory bodies to intermediate filaments in hepatocytes. A scanning electron microscopy study.

Livers from 12 mice fed griseofulvin for 4 to 6 months were perfused in situ with a detergent solution to extract lipid membranes leaving the cytoskeleton intact. Seven control mice were similarly studied. After 30 to 120 minutes perfusion, liver samples were examined by scanning electron microscopy and transmission electron microscopy. By light microscopy, Mallory bodies (MBs) were observed in pericentral hepatocytes. These were confirmed by transmission electron microscopy. Intermediate filaments (IFs) were observed in close apposition to MBs. Numerous IFs were seen throughout the cytoplasm. The 3-dimensional organization of the cytoskeleton and MBs were clearly visualized by scanning electron microscopy. The IFs were disorganized in the hepatocytes and formed small MBs in griseofulvin-treated mice. In the case of hepatocytes containing large MBs, there was an apparent decrease in the concentration of IFs. Transition forms of dense networks of IFs between the normal cytoskeleton and the MBs were noted in the cytoplasm between small MBs and the nucleus and also at the cell border. The IFs connected to the nucleus and invaded the MBs. The MBs appeared to form as a result of condensation or collapse of the IFs.

Animals↗