[Pathomorphological assessment of renal biopsy specimens: principles and directions for clinicians]. / Patomorfologiczna ocena biopunktatów nerek: podstawy i wytyczne dla klinicystów.

The renal biopsy is a principal diagnostic method to provide information on type, activity and the intensity of the disease. The aim of the article is to describe the handling, fixation and processing of the renal tissue in pathomorphological laboratories, as well as to provide any information about histopathological glomerular lesions observed in glomerulopathies. The assessment of the renal biopsies includes light microscopy, immunofluorescence microscopy and electron microscopy. In each case clinicians should provide information on the patient's clinical history and recent laboratory values. Immunomorphological evaluation of the renal biopsy specimen should be done in all cases. In view of the high cost of the electron microscopy it seems that the best solution is to preserve the renal tissue in epon and provide ultrastructural evaluation according to the clinical data and light microscopy and immunofluorescence findings. The diagnosis of glomerulopathies requires a close cooperation between clinicians and pathologists. Pathologists should have access to clinical data, and clinicians should understand the limitations of the pathomorphological techniques.

Digital image capture applied to electron microscopic examination of renal biopsies.

AIMS: Digital image capture systems to replace traditional film cameras are now available for most electron microscopes. For a diagnostic electron microscope laboratory the test of this new technology is in its application to the examination of renal biopsy specimens. METHODS: A long-term comparison is made between the work procedures employed with conventional film photography versus digital image capture in routine renal biopsy examination. RESULTS: Digital image capture has lead to a reduction in turnaround time and allows for more images to be collected per case, providing more diagnostic information. Ultrastructural measurement is made easier, accuracy of patient records is improved and electronic communication of results is more accessible. Significant operational cost savings are also possible. CONCLUSION: A quicker and more comprehensive assessment of renal biopsy specimens is possible using digital image capture for ultrastructural examination.

The continuing value of electron microscopy in surgical pathology.

For decades, transmission electron microscopy has played a valuable diagnostic role in surgical pathology. The continuing importance of electron microscopy, however, can be debated, given the major advances that have occurred in immunohistochemistry and other techniques. Electron microscopy retains excellent educational potential and broad research applicability, and it continues to be a necessity for the evaluation of a small subset of surgical pathology cases, such as renal biopsies and cilia specimens. The real controversy, then, centers on the contribution of electron microscopy in the evaluation of neoplasms. The opinion of many experts indicates that electron microscopy is still vital in the diagnostic assessment of some neoplasms, and that both electron microscopy and immunohistochemistry are more powerful when viewed as complementary rather than competitive techniques. For electron microscopy to be used to its potential, however, electron microscopists must function effectively as consultants. When optimally applied, electron microscopy remains an essential diagnostic tool.

Electron microscopy for tumour diagnosis: is it redundant?

The histopathological diagnosis of tumours has been transformed by immunohistochemistry. Used with experience and judgement, a panel of antibodies or antisera, combined when necessary with antigen retrieval, will enable the accurate typing of most problematic tumours. This has led many histopathologists to question whether the electron microscope has any residual utility for tumour diagnosis; the machines are large, costly to purchase and maintain, and will accept only minute samples of tissue. The following articles by Mierau and by Eyden, both strong advocates, comment on the current and future role of electron microscopy in tumour diagnosis.

Neuroendocrine carcinomas: role of immunocytochemistry and electron microscopy.

Neuroendocrine tumors occur in many sites of the body and can present significant diagnostic problems when poorly differentiated. To identify a tumor as neuroendocrine, pathologists commonly use either immunocytochemistry or electron microscopy. In this report, the various immunocytochemical reagents are reviewed along with the ultrastructural features of neuroendocrine tumors. Site-specific variations in neuroendocrine tumors are discussed. A cost-effectiveness evaluation was performed on tumors from one laboratory which showed that electron microscopy was a less expensive diagnostic modality if more than three antibodies were necessary to arrive at the correct pathological diagnosis.

Prolonged storage of fixative for electron microscopy: effects on tissue preservation for diagnostic specimens.

Prolonged storage of Karnovsky's fixative, at both 4 and -20 degrees C, is possible in the diagnostic electron microscopy setting. Ultrastructural detail was not compromised in specimens processed in fixative that had been stored for 6 months. Evidence of smooth muscle and neuroendocrine differentiation was present in the form of actin filaments/dense bodies and neurosecretory granules, respectively. No difference in preservation was detected between specimens fixed in freshly prepared Karnovsky's fixative and fixative that had been stored at either 4 or -20 degrees C for up to 6 months. Thus, community hospitals can be provided with Karnovsky's fixative on a semiannual basis for surgical pathology specimens that may require electron microscopy for diagnosis.

Electron microscopic examination of skin biopsy as a cost-effective tool in the diagnosis of lysosomal storage diseases.

In this report, we have summarized our 9-year experience of over 100 proven cases of lysosomal storage disease using electron microscopic evaluation of skin biopsies as a screening tool. The skin biopsy was very specific in establishing the diagnosis in only two disorders, namely neuronal ceroid lipofuscinosis and mucolipidosis IV. Although the biopsy was not diagnostic in other categories of storage diseases, it proved to be highly sensitive and provided valuable clues to direct further investigations on the basis of morphologic appearance of stored material and the cell type affected. Only in two cases of biochemically proven lysosomal storage disease was the morphologic diagnosis unable to be confirmed. We have compared the cost of screening for storage disorders using skin biopsy with the cost of performing multiple lysosomal enzyme assays. Our findings indicate that the skin biopsy, although more expensive than a single enzyme assay, provides an efficient, rapid, cost-effective tool to screen for more than 35 lysosomal storage disorders.

Setting of a low price CCD camera on the view window of TEM for printing out electron diffraction patterns.

In order to print out electron diffraction patterns quickly, an industrial CCD camera is conveniently set on the view window of an electron microscope. Although the observed pattern on the camera is distorted since the view direction has an angle of 41.5 degrees from the normal of the screen, however, the printed pattern is successfully restored to the correct one by varying the aspect ratio from 3:4 for the CCD camera to 1:1 for the printer. Note that cos(41.5) = 3/4. The camera used has a sensitivity of 1 lux. The aperture ratio of the lens is F 1.4, and the focal length is 50 mm.