Principles of ploidy analysis by static cytometry

Alterations in ACE and ABCG2 expression levels in the testes of rats subjected to atropine-induced toxicity

Atropine-induced damage is associated with enzyme and protein alterations. The aim of the present study was to investigate atropine‑induced alterations in testicular expression levels of angiotensin‑converting enzyme (ACE) and adenosine 5'-triphosphate binding cassette sub‑family G member 2 (ABCG2) following atropine treatment. Male Wistar rats received 15 mg/kg/day atropine for 7 days; control rats received an identical volume of saline, Following treatment, the testes were harvested for immunohistochemistry and in situ hybridization to examine the protein and gene expression levels of ACE and ABCG2 by digital image analysis. ACE gene and protein expression levels were significantly reduced in the testes of atropine‑treated rats, compared with control rats (P=0.0001 and P<0.001, respectively). In addition, ABCG2 gene and protein expression levels were significantly increased in the testes of atropine‑treated rats, compared with control rats (P=0.0017 and P<0.001, respectively). Thus, the results of the present study demonstrate that testicular protein and gene expression levels of ACE and ABCG2 were altered as a result of atropine‑induced toxicity in the rats. These alterations may result in abnormal testicular function, and the proteins and genes identified in the present study may be useful to elucidate the mechanisms underlying atropine‑induced toxicity and provide a direction for further studies.

Connexin 43, angiotensin II, endothelin 1, and type III collagen alterations in heart of rats having undergone fatal electrocution

Death due to accidental electrocution occurs frequently. The aim of this study was to investigate alterations in cardiac connexin 43 (Cx43), angiotensin II (Ang II), endothelin 1 (ET-1), and type III collagen associated with fatal electrocution.Twenty-four Sprague-Dawley rats were divided into control, fatal electrocution (220 V, 50 Hz, 60 seconds), and electrical injury (220 V, 50 Hz, 60 seconds) groups. Animals were deeply anesthetized with sodium pentobarbital before each treatment, with the anode connected to the left foreleg and the cathode to the right hindleg, followed by cervical dislocation. Control animals received cervical dislocation alone. Immunohistochemical analysis was performed to evaluate the cardiac protein expression of Cx43, Ang II, ET-1, and type III collagen. Sections were analyzed by digital image analysis.The expression of Cx43 was significantly reduced after fatal electrocution, with the integrated optical density also lower when compared with control (P < 0.05). Expression of both Ang II and ET-1 was significantly increased after fatal electrocution, supported by integrated optical density when compared with control (P < 0.05). But no significant difference was found in type III collagen expression between the fatal electrocution group and the control group.In summary, cardiac protein expression of Cx43, Ang II, and ET-1 was found to be significantly altered with fatal electrocution, suggesting that these 3 proteins may be important underlying mechanisms of death during fatal electrocution. The current findings indicate that such alterations would be reflected in abnormal cardiac function and a possible cause of sudden death.

Standardization in immunohistology

The rapid acceptance of immunohistology as an invaluable adjunct to morphologic diagnosis has been possible because of the development of new and more sensitive antibodies and detection systems that allow its application to formalin-fixed, paraffin-embedded tissue (FFPT). More importantly, antigen-retrieval techniques have resulted in some degree of consistency allowing immunohistology to be used reliably as a diagnostic tool. The advent of prognostic and predictive biomarkers, and the desire for individualized therapy has resulted in mounting pressure to employ the immunohistological assay in a quantitative manner. While it was not a major issue when the technique was employed in a qualitative manner, the numerous variables in the preanalytical and analytical phases of the test procedure that influence the immunoexpression of proteins in FFPT become critical to standardization. Tissue fixation is pivotal to antigen preservation but exposure to fixative prior to accessioning by the laboratory is not controlled. Antigen retrieval, crucial in the analytical phase, continues to be employed in an empirical manner with the actual mechanism of action remaining elusive. There is great variation in reagents, methodology, and duration of tissue processing and immunostaining procedure, and the detection systems employed are not standardized between laboratories. While many of these variables are offset by the application of antigen retrieval, which enables the detection of a wide range of antigens in FFPT, the method itself is not standardized. This myriad of variables makes it inappropriate to provide meaningful comparisons of results obtained in different laboratories and even in the same laboratory, as in current practice, each specimen experiences different preanalytical variables. Furthermore, variables in interpretation exist and cutoff thresholds for positivity differ. Failure to recognize false-positive and false-negative stains leads to further errors of quantitative measurement. Many of the problems relating to the technology and interpretation of immunostaining originate from failure to recognize that this procedure is different from other histological stains and involves many more steps that cannot be monitored until the end result is attained. While several remedial measures can be suggested to address some of these problems, accurate and reproducible quantitative assessment of immunostains presently remains elusive as important variables that impact on antigen preservation in the paraffin-embedded biopsy -cannot be standardized.

Immunohistology--past, present, and future

The rapid development of immunohistochemistry, a morphology-based technique, has come about through refinements in detection systems and an increasing range of sensitive and specific antibodies that have allowed application of the technique to formalin-fixed, paraffin-embedded tissues. The introduction of heat-induced antigen retrieval has been a significant milestone to compliment these developments so that the immunohistochemistry is firmly entrenched as an indispensable adjunct to morphologic diagnosis. Although this ancillary stain was initially used in a qualitative manner, problems surrounding the many variables that influence antigen preservation in formalin-fixed, paraffin-embedded tissues were not a major issue and laboratories strived to optimize their staining protocols to the material they accessioned and processed. The advent of personalized medicine and targeted cancer treatment has imposed the need to quantitate the stain reaction product and has resulted in calls to standardize the process of immunostaining. A closer examination of the variables that influence the ability to show antigens in formalin-fixed, paraffin-embedded tissues revealed many important variables, particularly in the preanalytical phase of the assay, that are beyond the control of the accessioning laboratory. Although analytical factors have the potential to be standardized, the actions of many pivotal procedures including fixation and antigen retrieval are not completely understood. Postanalytical processes including threshold and cut-off values require consensus and standardization and it is clear that some of these goals can be achieved through the direction of national and international organizations associated with cancer diagnosis and treatment. With the ability to serve as a surrogate marker of many genetic abnormalities, immunohistochemistry enters a new era and the need to better understand some of the mechanisms fundamental to the technique become more pressing and the development of true quantitative assays is imperative. There is also an increasing appreciation that the technique highlights patterns of staining that reflect exquisite localization to organelles and tissue structures that are not appreciable in routine stains, adding a further dimension to morphologic diagnosis.

Computer-assisted differential diagnosis of malignant mesothelioma based on syntactic structure analysis

BACKGROUND

Malignant mesothelioma, a mesoderm-derived tumor, is related to asbestos exposure and remains a diagnostic challenge because none of the genetic or immunohistochemical markers have yet been proven to be specific. To assist in the identification of mesothelioma and to differentiate it from other common lesions at the same location, we have tested the performance of syntactic structure analysis (SSA) in an automated classification procedure.

MATERIALS AND METHODS

Light-microscopic images of tissue sections of malignant mesothelioma, hyperplastic mesothelium, and adenocarcinoma were analyzed using parameters selected from the Voronoi diagram, Gabriel's graph, and the minimum spanning tree which were classified with a K-nearest-neighbor algorithm.

RESULTS

Results showed that mesotheliomas were diagnosed correctly in 74% of the cases; 76% of the adenocarcinomas were correctly graded, and 88% of the mesotheliomas were correctly typed. The performance of the parameters was dependent on the obtained classification (i.e., tumor-tumor versus tumor-benign).

CONCLUSIONS

Our results suggest that SSA is valuable in the differential classification of mesothelioma and that it supplements a visually appraised diagnosis. The recognition scores may be increased by a combination of SSA with, for example, cellular or nuclear parameters, measured at higher magnifications to form a solid base for fully automated expert systems.