Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Microscopy”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources
PubMed1994

The role of microscopy in the diagnosis of sexually transmitted infections in women.

INTRODUCTION: Microscopy of genital secretions is routinely performed in female patients attending genitourinary medicine clinics. It diagnoses only 50-70% of gonorrhoea, 40-80% of trichomoniasis and has no value in the diagnosis of chlamydial infection. This study was therefore conducted to reassess the role of routine microscopy in female patients. SUBJECTS AND METHODS: One thousand consecutive women attending the genitourinary medicine clinic of the General Hospital, Birmingham, were studied prospectively. The first 500 women had routine microscopy performed. The second 500 women had microscopy performed only if they complained of symptoms, were known gonorrhoea contacts, or when an abnormal vaginal discharge was noted by the examining clinician. RESULTS: In the routine microscopy group, 46 (9.2%) women had gonorrhea; 30 of these were diagnosed by microscopy and subsequently confirmed on culture and 16 by culture alone; of these, two (4.3%) defaulted from follow-up and were not treated. In the selective microscopy group 139 women (28%) did not require microscopy. Thirty three women had positive culture for Neisseria gonorrhoeae. Of these, seven were diagnosed by microscopy, the rest by culture alone. All patients were successfully treated. No patients with trichomoniasis in the routine microscopy group and only two (4.3%) in the selective microscopy group were lost to follow-up. CONCLUSION: In this study, the selective policy in the second group led to a significant reduction in microscopy. Such a policy has the benefits of saving time for patients and staff, more efficient utilisation of manpower and resources. It did not lead to any significant delay in the diagnosis and treatment of patients with sexually transmitted infections.

Adolescent↗
PubMed1997

Appositions made by axons of descending interneurons in the guinea-pig small intestine, investigated by confocal microscopy.

There are four major classes of descending interneurons in the myenteric plexus of the guinea-pig small intestine. In this study, the connections made by two of these classes of descending interneurons with other interneurons and with inhibitory motor neurons have been investigated using confocal, conventional fluorescence and electron microscopy. The terminals of descending interneurons known to contain both bombesin (BN) and nitric oxide synthase (NOS) were identified by BN immunoreactivity (IR). Cholinergic interneurons known to contain somatostatin (SOM) were identified by SOM-IR. The connections of these two groups of interneurons with the following three classes of nerve cell bodies were examined: those with NOS-IR that also contain gamma-aminobutyric acid (GABA) (inhibitory motor neurons), those with only NOS-IR (descending interneurons and inhibitory motor neurons) and those with only GABA-IR (motor neurons). The BN-IR and SOM-IR interneurons were found to form connections with each other, and both types of interneurons provided inputs to motor neurons. Most previous analyses of interconnections in the enteric plexuses have been by conventional fluorescence microscopy and electron microscopy. In the present work these are compared with confocal microscopy. BN-IR varicosities formed pericellular baskets around each class of nerve cell that were easily identifiable with all techniques. Using confocal microscopy, BN-IR varicosities that were in contact with NOS-IR and GABA-IR nerve cells were quantified. Confocal microscopy demonstrated over twice as many contacts as were shown by a previous electron microscopic study. In contrast, conventional fluorescence microscopy showed little indication that SOM-IR varicosities formed inputs to NOS-IR or GABA-IR nerve cells, despite the fact that confocal microscopy revealed direct appositions and electron microscopy revealed synapses. This study has shown that confocal analysis is a valuable adjunct to conventional fluorescence microscopy for determining neuronal circuitry. Moreover, it allows a more rapid collection of data than does electron microscopy. It is concluded that chains of BN-IR and SOM-IR interneurons from descending pathways in the small intestine and that both types of interneuron connect with muscle motor neurons.

Animals↗
PubMed2006

Fluorescence versus conventional sputum smear microscopy for tuberculosis: a systematic review.

Most of the world's tuberculosis cases occur in low-income and middle-income countries, where sputum microscopy with a conventional light microscope is the primary method for diagnosing pulmonary tuberculosis. A major shortcoming of conventional microscopy is its relatively low sensitivity compared with culture, especially in patients co-infected with HIV. In high-income countries, fluorescence microscopy rather than conventional microscopy is the standard diagnostic method. Fluorescence microscopy is credited with increased sensitivity and lower work effort, but there is concern that specificity may be lower. We did a systematic review to summarise the accuracy of fluorescence microscopy compared with conventional microscopy. By searching many databases and contacting experts, we identified 45 relevant studies. Sensitivity, specificity, and incremental yield were the outcomes of interest. The results suggest that, overall, fluorescence microscopy is more sensitive than conventional microscopy, and has similar specificity. There is insufficient evidence to determine the value of fluorescence microscopy in HIV-infected individuals. The results of this review provide a point of reference, quantifying the potential benefit of fluorescence microscopy, with which the increased cost and technical complexity of the method can be compared to determine the possible value of the method under programme conditions.

Cytodiagnosis↗
PubMed2000

Increase in the sensitivity for melanoma diagnosis by primary care physicians using skin surface microscopy.

BACKGROUND: Skin surface microscopy (oil epiluminescence microscopy, dermoscopy, dermatoscopy) has been shown to increase the diagnostic accuracy of melanoma. However, all studies to date have been in an expert setting. OBJECTIVES: To determine whether primary care physicians (PCP) (general practitioners) could improve their melanoma diagnosis using surface microscopy after a short education intervention. METHODS: Seventy-four practising PCP completed a pretest of 50 melanomas and 50 atypical non-melanoma pigmented skin lesions (PSL) containing matched clinical and surface microscopy photographs. PCP were randomized between a surface microscopy education intervention or control group, followed by an identical post-test. RESULTS: Following training there was a significant improvement in the post-test vs. pretest in both clinical melanoma diagnosis (62.7% vs. 54.6%; P = 0.007) and surface microscopy melanoma diagnosis (75.9% vs. 57.8%; P = 0.000007). No difference was found in the control group between the post-test vs. pretest clinical melanoma diagnosis (53.7% vs. 50.6%; P = 0.21) or the surface microscopy melanoma diagnosis (54.8% vs. 52.9%; P = 0.56). Following training there was a significant improvement in the diagnosis of melanoma using surface microscopy vs. clinical diagnosis (75.9% vs. 62.7%; P = 0.000007), which was absent in the control group (54.8% vs. 53.7%; P = 0.59). No significant difference was found in clinical vs. surface microscopy post-test results for non-melanoma PSL in either the intervention group or control group. Improvement in the sensitivity for the diagnosis of melanoma with surface microscopy was seen without a decrease in specificity; this indicated that the effect should occur without increasing the number of needless excisions. CONCLUSIONS: All PCP in countries where melanoma leads to significant mortality should be trained in skin surface microscopy.

Clinical Competence↗
PubMed1999

Confocal microscopy in the iridocorneal endothelial syndrome.

AIMS: To report the appearances of iridocorneal endothelial (ICE) syndrome from real time, white light confocal microscopy. METHODS: Three consecutive patients, each with ICE syndrome, were examined prospectively. Corneal specular and confocal microscopic examinations were performed in all three patients. In the first patient, a penetrating keratoplasty was performed and the cornea was examined by light and scanning electron microscopy. No surgery was performed in the remaining two patients. RESULTS: In the first patient corneal oedema prevented endothelial specular microscopy. Confocal microscopy performed before penetrating keratoplasty successfully revealed abnormal epithelial-like endothelial cells. Histological examinations of the cornea following penetrating keratoplasty revealed the presence of multilayered endothelial cells with epithelial features (microvilli). In the remaining two patients, specular microscopy showed the presence of ICE cells with typical dark/light reversal. Confocal microscopy demonstrated groups of endothelial cells with epitheloid appearances. In all three patients, the contralateral endothelial appearance was normal by specular and confocal microscopy, except for moderate endothelial polymegathism in one patient. Epithelial-like endothelial cells were characterised by prominent nuclei on confocal microscopy. CONCLUSIONS: The application of confocal microscopy indicates that the ICE syndrome is characterised by epitheloid changes in the endothelium. Confocal microscopy may be used to diagnose the ICE syndrome by demonstrating epithelial-like endothelial cells with hyperreflective nuclei. This technique is especially of value in cases of corneal oedema, since specular microscopy may fail to image the endothelium in such cases.

Aged↗
PubMed2003

Virtual microscopy as a tool for proficiency testing in cytopathology: a model using multiple digital images of Papanicolaou tests.

BACKGROUND: Modern digital cameras can acquire images from cytologic slides at sufficient resolution to allow for digital enlargement and scrolling on a video monitor, allowing for the simulation of microscopy using a computer. OBJECTIVE: The purpose of this study was to develop a tool for proficiency testing in cytopathology using multiple digital images of Papanicolaou tests. METHODS: Nine images were photographed from each of 10 Papanicolaou tests at x100 optical magnification, 3400 x 2300-pixel resolution, using a light microscope and a digital camera. All images from each case were tiled in a single canvas with Photoshop 4.0 software. Two cytopathologists and 3 cytotechnologists interpreted these "virtual slides" using a computer and graded diagnostic codes (PAP program, College of American Pathologists). Subjects were retested a year later using the glass slides from the same cases and routine microscopy. Both test results, by diagnostic code, were compared with the McNemar test of symmetry. RESULTS: The 5 test subjects provided 42 and 50 correct diagnostic codes by "virtual microscopy" and light microscopy, respectively. No significant asymmetry in results obtained by virtual microscopy and light microscopy was encountered with the McNemar test of symmetry. All test answers were correctly classified by selection series, using both virtual microscopy and light microscopy, and the responses would have been graded as 100% by current PAP program scoring guidelines. This suggests that virtual microscopy could be used for proficiency testing purposes. CONCLUSIONS: A simple virtual microscopy method designed to challenge participants to locate and diagnose cells of interest was effective for the administration of standardized proficiency tests. Virtual microscopy methods that rely on single-plane images to locate and diagnose cells of interest could provide effective proficiency testing tools prior to the development of more computationally intensive systems that represent an entire Papanicolaou test at multiple focal planes.

Computer Simulation↗
PubMed1992

Visualization of myocardial cellular architecture using acoustic microscopy.

The resolution of an ultrasound transducer depends on its frequency. The resolution improves when higher frequency transducers are used. A 1000 MHz transducer has a resolution of approximately 1 micron. Acoustic microscopy utilizes very high-frequency ultrasound (600 to 1000 MHz) to visualize structures on a microscopic level. Unstained, deparaffinized, 5 microns sections of myocardial biopsy specimens from 10 patients were placed on a slide and imaged using an Olympus UH3 scanning acoustic microscope. To compare with light microscopy, the section used for acoustic microscopy was subsequently stained with hematoxylin and eosin and a serial section from the paraffin block was stained with PTAH stain. Myocytes, myofibrils, and interstitial tissue were accurately imaged. Pathologic phenomena such as cell fallout, interstitial fibrosis, and lymphocytic infiltration were identified by acoustic microscopy. Intramural vessels, nuclei of endothelial cells, and the media were clearly identified by this technique. There was close correlation between findings by acoustic microscopy and light microscopy. Acoustic microscopy permitted the visualization of cardiac cellular detail with a resolution similar to that of light microscopy. Unlike light microscopy, acoustic microscopy requires no staining of the specimen.

Biopsy↗
PubMed2000

The diagnostic value of electron microscopy in human immunodeficiency virus-positive patients with gastrointestinal disease.

BACKGROUND: Our aim was to determine the diagnostic value of electron microscopy in evaluating the etiology of gastrointestinal disease in patients infected with the human immunodeficiency virus (HIV). METHODS: A retrospective review of electron microscopic and light microscopic results of all HIV-positive patients with gastrointestinal and liver diseases was made during a 3-year period from June 1995 to June 1998. RESULTS: A total of 145 HIV-positive patients had their electron microscopy specimens reviewed. Of these, 136 were investigated for diarrhea, and the other 9 for increased liver enzymes. Twenty-seven of the 145 (18.6%) HIV-positive patients had a pathogen identified by electron microscopy, compared with only 13 of 145 (9%) identified by light microscopy (P < 0.005). The sensitivity of light microscopy for detecting opportunistic pathogens was 68%. Twenty-one of the 27 (77.8%) patients diagnosed by electron microscopy had microsporidiosis, and the most commonly diagnosed species was Enterocytozoon bieneusi. Light microscopy failed to identify 12 cases of microsporidiosis and 2 cases of leishmaniasis. CONCLUSIONS: Electron microscopy contributes substantially to the identification of pathogens in HIV-positive patients. Light microscopy failed to identify one of every two pathogens diagnosed by electron microscopy.

Adult↗
PubMed1999

Confocal microscopy in cornea guttata and Fuchs' endothelial dystrophy.

AIMS: To report the appearances of cornea guttata and Fuchs' endothelial dystrophy from white light confocal microscopy. METHODS: Seven eyes of four consecutive patients with cornea guttata were prospectively examined. Of the seven eyes, three also had corneal oedema (Fuchs' dystrophy). In vivo white light tandem scanning confocal microscopy was performed in all eyes. Results were compared with non-contact specular microscopy. RESULTS: Specular microscopy was precluded by corneal oedema in one eye. In the remaining six eyes, it demonstrated typical changes including pleomorphism, polymegathism, and the presence of guttae appearing as dark bodies, some with a central bright reflex. In all seven eyes, confocal microscopy revealed the presence of round hyporeflective images with an occasional central highlight at the level of the endothelium. Changes in cell morphology and size were readily appreciated. CONCLUSION: By comparison with specular microscopy, the hyporeflective images with an occasional central highlight seen on confocal microscopy are consistent with the presence of guttae. Confocal microscopy may confirm the diagnosis of cornea guttata and Fuchs' endothelial dystrophy by demonstrating the presence of guttae. This technique is especially valuable in cases of corneal oedema, where specular microscopy may fail to visualise the endothelium. However, specular microscopy should remain the method of choice to evaluate the endothelium, principally because it is easier to use.

Adult↗
PubMed1985

Small round cell neoplasms: can electron microscopy and immunohistochemical studies accurately classify them?

The answer to the question posed in the title, "Small Round Cell Neoplasms: Can Electron Microscopy and Immunohistochemical Studies Accurately Classify Them?", is obviously "yes"; but a qualified yes--generally yes, perhaps with expertise usually yes, but never just plain yes. Some cases certainly will defy the best attempts even of the most expert in the application of these "special" techniques. And embarrassing as it may be for those of us infatuated with the latest technology to admit, it is with the difficult case especially that old-fashioned technology so often must be depended upon. In his excellent recent appraisal of the role of a variety of special techniques in this application, Triche offers the following comment: "Overall, electron microscopy is probably the most universally useful of all diagnostic techniques other than light microscopy in round cell tumors." The data from our studies certainly point to the same conclusion. With each of the tumors, electron microscopy demonstrated itself to be more reliable than immunohistochemistry. Electron microscopy offers not only greater sensitivity and specificity, but also greater versatility. Immunohistochemistry allows hypothesis testing only. Electron microscopy, on the other hand, can provide answers even when the right questions are not being asked. For example, if a particular small round cell tumor under investigation happens in actuality to represent something other than the neuroblastoma which it is being considered (e.g., a granulocytic sarcoma, liposarcoma, Wilm's tumor, etc.), electron microscopy can reveal this fact, but a neuron-specific enolase stain cannot. Parenthetically, it should also be said that electron microscopy has proven particularly well suited to the examination of fine-needle aspiration specimens. The two spare many patients in our institution the need for a major operative procedure to establish a secure tissue diagnosis. Immunohistochemistry does have a role to play but it is, at least in our opinion, clearly secondary to that of electron microscopy. The concept of replacing electron microscopy with a battery of immunostains has often been advocated as an economic measure, but this argument begins quickly to lose its weight as the number stains included in the battery is increased to cover the diagnostic possibilities. Giving consideration to the capriciousness of some of these stains, there exists with this also an increasing possibility of a spurious or misinterpreted result leading to an errant diagnosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinoma, Small Cell↗
PubMed1995

Robert Feulgen Prize Lecture 1995. Electronic light microscopy: present capabilities and future prospects.

Electronic light microscopy involves the combination of microscopic techniques with electronic imaging and digital image processing, resulting in dramatic improvements in image quality and ease of quantitative analysis. In this review, after a brief definition of digital images and a discussion of the sampling requirements for the accurate digital recording of optical images, I discuss the three most important imaging modalities in electronic light microscopy--video-enhanced contrast microscopy, digital fluorescence microscopy and confocal scanning microscopy--considering their capabilities, their applications, and recent developments that will increase their potential. Video-enhanced contrast microscopy permits the clear visualisation and real-time dynamic recording of minute objects such as microtubules, vesicles and colloidal gold particles, an order of magnitude smaller than the resolution limit of the light microscope. It has revolutionised the study of cellular motility, and permits the quantitative tracking of organelles and gold-labelled membrane bound proteins. In combination with the technique of optical trapping (optical tweezers), it permits exquisitely sensitive force and distance measurements to be made on motor proteins. Digital fluorescence microscopy enables low-light-level imaging of fluorescently labelled specimens. Recent progress has involved improvements in cameras, fluorescent probes and fluorescent filter sets, particularly multiple bandpass dichroic mirrors, and developments in multiparameter imaging, which is becoming particularly important for in situ hybridisation studies and automated image cytometry, fluorescence ratio imaging, and time-resolved fluorescence. As software improves and small computers become more powerful, computational techniques for out-of-focus blur deconvolution and image restoration are becoming increasingly important. Confocal microscopy permits convenient, high-resolution, non-invasive, blur-free optical sectioning and 3D image acquisition, but suffers from a number of limitations. I discuss advances in confocal techniques that address the problems of temporal resolution, spherical and chromatic aberration, wavelength flexibility and cross-talk between fluorescent channels, and describe new optics to enhance axial resolution and the use of two-photon excitation to reduce photobleaching. Finally, I consider the desirability of establishing a digital image database, the BioImage database, which would permit the archival storage of, and public Internet access to, multidimensional image data from all forms of biological microscopy. Submission of images to the BioImage database would be made in coordination with the scientific publication of research results based upon these data.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1999

Ciliary motility at light microscopy: a screening technique for ciliary defects.

To verify whether or not ciliary motility can be reliably assessed by light microscopy alone, we examined the nasal brushings of 53 patients with suspected ciliary dyskinesia and 10 healthy controls. The results of light microscopy were compared with cilia ultrastructure assessed with electron microscopy. Ciliary motility was significantly related with cilia ultrastructure. However, eight cases of lung disease due to bronchiectasis of unknown origin had immotile cilia on light microscopy, but normal ciliary ultrastructure on electron microscopy. Instances of normal and abnormal ultrastructure were detected in one case with motile cilia. There was an 83% agreement between electron microscopy and light microscopy. Sensitivity and specificity of light microscopy were 92% and 80%, respectively. In conclusion, light microscopy evaluation of ciliary motility does not appear to be a reliable screening test for ciliary dyskinesia because it does not quantify ciliary beat activity, which is a criterion for deranged ciliary motion. A complete evaluation of ciliary ultrastructure together with in vivo, if applicable, or in vitro function test (namely, the analysis of ciliary beat frequencies and/or waveform) is required for a definite diagnosis of ciliary dyskinesia.

Adolescent↗
PubMed1997

Advances in the microscopy of osteoarthritis.

This review describes recent contributions made by microscopy to the understanding of osteoarthritis, a clinical syndrome the pathological features of which are well defined by classical white light microscopy. The fluorescence and reflected light, conventional and scanning optical microscopy of excised osteoarthritic tissue preparations, from human and animal sources, has enabled the identification of cell proteins such as S100, of matrix components such as the proteoglycans and collagens, and of adhesion molecules including fibronectin, the integrins and tenascin. Comparable microscopic studies have been made of cell and tissue culture preparations of osteoarthritic cartilage and synovium. Scanning optical microscopy also allows the rapid measurement, in hydrated osteoarthritic tissues, of cell density, cell size, surface roughness and other parameters. The importance of water in sustaining the physical attributes of cartilage is accepted and new forms of electron microscopy can play important parts in the study of unfixed osteoarthritic cartilage. These methods include the low temperature scanning electron microscopy and electron probe x-ray microanalysis of hydrated bulk material and the high resolution transmission electron microscopy of low temperature replicas of cartilage surfaces. Understanding of osteoarthritis has been facilitated by these advances and will continue to be enhanced as new techniques of microscopy evolve.

Animals↗
PubMed2003

High-resolution MR imaging of triangular fibrocartilage complex (TFCC): comparison of microscopy coils and a conventional small surface coil.

OBJECTIVE: To compare MR images of the triangular fibrocartilage complex (TFCC) using microscopy coils with those using a conventional surface coil qualitatively and quantitatively. DESIGN AND PATIENTS: Proton density-weighted images and T2*-weighted images of the TFCC from ten normal volunteers were obtained with a conventional surface coil (C4 coil; 80 mm in diameter), a 47-mm microscopy surface coil and a 23-mm microscopy surface coil) at 1.5 T. Qualitative image analysis of MR images with three coils was performed by two radiologists who assigned one of five numerical scores (0, nonvisualization; 1, poor; 2, average; 3, good; 4, excellent) for five TFCC components, which were disc proper, triangular ligament, meniscus homologue, ulnotriquetral and ulnolunate ligament. Quantitative analysis included the signal-to-noise ratio (S/N) of the disc proper of TFCC, the lunate cartilage, the lunate bone and the contrast-noise-ratio (C/N) between articular cartilage and disc proper or bone marrow were measured. RESULTS: All structures show higher scores qualitatively on MR with microscopy coils than those with a C4 coil, and the difference was significant with the exception of the ulnolunate ligament. MR with microscopy coils showed significantly higher S/N values than those with a conventional surface coil (P<0.05 to P<0.001). T2*-weighted images using microscopy coils showed significantly higher cartilage-disc proper C/N and cartilage-bone marrow C/N (P<0.01 to P<0.001). On proton density-weighted images, the C/N between cartilage and disc proper with two microscopy coils was significantly higher (P<0.01) than that with a conventional coil. CONCLUSION: High-resolution MR images of the normal wrist using microscopy coils were superior to those using a conventional surface coil qualitatively and quantitatively. High-resolution MR imaging with a microscopy coil would be a promising method to diagnose TFCC lesions.

Adult↗
PubMed1984

Uses and contributions of diagnostic electron microscopy in surgical pathology: a study of 20 Veterans Administration hospitals.

Although the capability of electron microscopy to contribute to histopathologic diagnosis in selected instances, e.g., renal biopsies and biopsies of certain tumors, is generally recognized, its contribution in a broader range of surgical pathology accessions is not well established. To gain further information concerning this aspect of the use of electron microscopy, 7,193 surgical pathology reports, 290 (4 per cent) of which included electron microscopic findings, were analyzed; these reports represented all such accessions during the same single month at 20 VA medical centers. It was found that malignancies constituted 62 per cent of the lesions examined by electron microscopy but only 20 per cent of the total number of surgical cases examined by light microscopy. It was also found that the distribution of specimens by tissue site of origin differed considerably for specimens examined by electron microscopy and light microscopy; positive contributions of electron microscopy to diagnosis were found in 146 of the 290 electron microscopy cases (50 per cent), with higher percentages found in malignancies and in certain tissue site subsets (lower respiratory tract, soft tissue, kidney, skin, and lymph nodes with metastases); failure to examine some specimens (lung metastases to lymph nodes or other tissues and endobronchial biopsy specimens) suggests slight, but common, underutilization of electron microscopy in diagnosis.

Adult↗
PubMed2004

Quantitative phase amplitude microscopy IV: imaging thick specimens.

The ability to image phase distributions with high spatial resolution is a key capability of microscopy systems. Consequently, the development and use of phase microscopy has been an important aspect of microscopy research and development. Most phase microscopy is based on a form of interference. Some phase imaging techniques, such as differential interference microscopy or phase microscopy, have a low coherence requirement, which enables high-resolution imaging but in effect prevents the acquisition of quantitative phase information. These techniques are therefore used mainly for phase visualization. On the other hand, interference microscopy and holography are able to yield quantitative phase measurements but cannot offer the highest resolution. A new approach to phase microscopy, quantitative phase-amplitude microscopy (QPAM) has recently been proposed that relies on observing the manner in which intensity images change with small defocuses and using these intensity changes to recover the phase. The method is easily understood when an object is thin, meaning its thickness is much less than the depth of field of the imaging system. However, in practice, objects will not often be thin, leading to the question of what precisely is being measured when QPAM is applied to a thick object. The optical transfer function formalism previously developed uses three-dimensional (3D) optical transfer functions under the Born approximation. In this paper we use the 3D optical transfer function approach of Streibl not for the analysis of 3D imaging methods, such as tomography, but rather for the problem of analysing 2D phase images of thick objects. We go on to test the theoretical predictions experimentally. The two are found to be in excellent agreement and we show that the 3D imaging properties of QPAM can be reliably predicted using the optical transfer function formalism.

Animals↗
PubMed1994

Value of electron microscopy in diagnosis of renal disease.

AIMS: To assess the role and value of electron microscopy in the diagnosis of renal disease. METHODS: Retrospective evaluation of 88 renal biopsy specimens received for primary diagnosis by assessment of the contribution of electron microscopy to the final diagnosis in the knowledge of the light microscopy and immunofluorescence findings. RESULTS: Electron microscopy had an important diagnostic role in 75% of cases and was essential or necessary for diagnosis in 25%. In 25% of cases electron microscopy was considered unhelpful in diagnosis. CONCLUSION: Electron microscopy has an integral role in the diagnosis of renal disease, and tissue should be taken for electron microscopy in all cases if possible. In some selected cases once the light microscopy and immunofluorescence findings are known it may be possible to forego electron microscopic examination. Electron microscopy is particularly useful in the differential diagnosis of minimal change disease and the nephrotic syndrome.

Adolescent↗
PubMed1989

A reevaluation of sputum microscopy and culture in the diagnosis of pulmonary tuberculosis.

This prospective study was undertaken to determine the interpretation of "scanty-positive" acid-fast bacilli on microscopy and to reevaluate simultaneous microscopy and culture of sputum for the accurate diagnosis of pulmonary tuberculosis (PTB). A total of 2,560 specimens were processed from 727 patients. There were 435 positive specimens (17.0 percent), originating from 139 patients, 10 by microscopy only, 176 by culture only, and 249 on both microscopy and culture. Review of the hospital records showed that 107 patients had PTB, 1 had Mycobacterium kansasii colonization, and 31 were thought not to have PTB. Sensitivity and specificity were 53.1 and 99.8 percent for microscopy, 81.5 and 98.4 percent for culture, and 77.6 and 100 percent for microscopy and culture, respectively. Seventy-five microscopy specimens (46 patients) were reported as scanty-positive, of which five (four patients) were deemed false positives, yielding a positive predictive value of 93.3 percent. In those patients with positive sputum microscopy, acid-fast bacilli were detected in one of the first four specimens. Seven isolates (three patients) were mycobacteria other than tubercle (0.27 percent of specimens and 1.6 percent of mycobacteria cultured). Despite the ready availability of laboratory evidence of disease, only 73 percent of cases were diagnosed by ward staff and 36 percent notified by the primary physician. Eleven patients (10.3 percent) died, six of whom had not received diagnoses of PTB before death. Sputum microscopy and culture remains reliable despite Bayesian predictions when applied to a population with a decreasing incidence of tuberculosis.

Bacteriological Techniques↗