Dextran Polymer Conjugate Two-Step Visualization System for Immunohistochemistry: A Comparison of EnVision+ With Two Three-Step Avidin-Biotin Techniques

Immunohistochemistry and Immunofluorescence

Immunohistochemistry (IHC) is one of the most widely used protein detection techniques. The principle of this technique is based on the binding of a specific antibody to a matching specific antigen in tissue. The bound antigen-antibody complex then is visualized using a range of detection techniques. IHC uses a number of different enzymatic labels, such as peroxidase and alkaline phosphatase, for the detection of the antigens of interest whereas immunofluorescence (IF) uses a fluorescent signal. In this chapter, IHC will be described using the peroxidase label. Both IHC and IF can be used on formalin-fixed paraffin-embedded (FFPE) or appropriately processed fresh tissues. IHC/IF can be multiplexed to detect more than one antigen at a time, or may be sequentially stained to detect multiple targets. These techniques are routinely used in diagnostic pathology laboratories, not just for diagnostic purposes but many biomarkers are used for patient staging, treatment allocation, and prognostication. Immunofluorescence is routinely used for the detection of antibodies and antigens in freshly biopsied tissues, particularly for immune-mediated and vesiculobullous lesions. In this chapter, the principles of IHC are reviewed followed by examples of IHC and IF staining using readily available antibodies. Steps and processes involved in IHC/IF double staining are also described.

Distribution of tau hyperphosphorylation in canine dementia resembles early Alzheimer's disease and other tauopathies

Some aged community dogs acquire a degenerative syndrome termed Canine Cognitive Dysfunction (CCD) that resembles human dementia because of Alzheimer’s Disease (AD), with comparable cognitive and behavioral deficits. Dogs also have similar neuroanatomy, share our domestic environment and develop amyloid‐β plaques, making them likely a valuable ecological model of AD. However, prior investigations have demonstrated a lack of neurofibrillary tau pathology in aged dogs, an important hallmark of AD, though elevated phosphorylated tau (p‐tau) at the Serine 396 (S396) epitope has been reported in CCD. Here using enhanced immunohistochemical methods, we investigated p‐tau in six CCD brains and six controls using the AT8 antibody (later stage neurofibrillary pathology), and an antibody against S396 p‐tau (earlier stage tau dysfunction). For the first time, we systematically assessed the Papez circuit and regions associated with Braak staging and found that all CCD dogs displayed elevated S396 p‐tau labeling throughout the circuit. The limbic thalamus was particularly implicated, with a similar labeling pattern to that reported for AD neurofibrillary pathology, especially the anterior nuclei, while the hippocampus exhibited dysfunction confined to synaptic layers and efferent pathways. The cingulate and temporal lobes displayed significantly greater tauopathy than the frontal and occipital cortices, also reflective of early Braak staging patterns in AD. Immunofluorescence confirmed that S396 was accumulating within neuronal axons, somata and oligodendrocytes. We also observed AT8 labeling in one CCD brain, near the transentorhinal cortex in layer II neurons, one of the first regions to be affected in AD. Together, these data demonstrate a concordance in regional distribution of tauopathy between CCD and AD, most evident in the limbic thalamus, an important step in further validating CCD as a translational model for human AD and understanding early AD pathogenic mechanisms.

Standardization of Diagnostic Immunohistochemistry: Literature Review and Geisinger Experience

Context

Immunohistochemistry has become an indispensable ancillary technique in anatomic pathology laboratories. Standardization of every step in preanalytic, analytic, and postanalytic phases is crucial to achieve reproducible and reliable immunohistochemistry test results.

Objective

To standardize immunohistochemistry tests from preanalytic, analytic, to postanalytic phases.

Data Sources

Literature review and Geisinger (Geisinger Medical Center, Danville, Pennsylvania) experience.

Conclusions

This review article delineates some critical points in preanalytic, analytic, and postanalytic phases; reiterates some important questions, which may or may not have a consensus at this time; and updates the newly proposed guidelines on antibody validation from the College of American Pathologists Pathology and Laboratory Quality Center. Additionally, the article intends to share Geisinger's experience with (1) testing/optimizing a new antibody and troubleshooting; (2) interpreting and reporting immunohistochemistry assay results; (3) improving and implementing a total immunohistochemistry quality management program; and (4) developing best practices in immunohistochemistry.

When tissue antigens and antibodies get along: revisiting the technical aspects of immunohistochemistry--the red, brown, and blue technique

Once focused mainly on the characterization of neoplasms, immunohistochemistry (IHC) today is used in the investigation of a broad range of disease processes with applications in diagnosis, prognostication, therapeutic decisions to tailor treatment to an individual patient, and investigations into the pathogenesis of disease. This review addresses the technical aspects of immunohistochemistry (and, to a lesser extent, immunocytochemistry) with attention to the antigen-antibody reaction, optimal fixation techniques, tissue processing considerations, antigen retrieval methods, detection systems, selection and use of an autostainer, standardization and validation of IHC tests, preparation of proper tissue and reagent controls, tissue microarrays and other high-throughput systems, quality assurance/quality control measures, interpretation of the IHC reaction, and reporting of results. It is now more important than ever, with these sophisticated applications, to standardize the entire IHC process from tissue collection through interpretation and reporting to minimize variability among laboratories and to facilitate quantification and interlaboratory comparison of IHC results.

Thirteen-week inhalation toxicity of 1,4-dioxane in rats

Thirteen-week inhalation toxicity of 1,4-dioxane was examined by repeated inhalation exposure of male and female F344 rats to 0 (control), 100, 200, 400, 800, 1600, 3200, or 6400 ppm (v/v) 1,4-dioxane vapor for 6 h/day and 5 days/wk. All the 6400-ppm-exposed males and females died during the first week. Terminal body weight decreased, and relative weights of liver, kidney, and lung increased. AST increased in the 200 ppm-and 3200-ppm-exposed females, and ALT increased in the 3200-ppm-exposed males and females. Nuclear enlargement of nasal respiratory epithelial cells occurring in the 100-ppm-exposed males and females was the most sensitive, followed by the enlarged nuclei in the olfactory, tracheal, and bronchial epithelia. 1,4-Dioxane-induced liver lesions occurred at higher exposure concentrations than the nasal lesions did, and were characterized by single-cell necrosis and centrilobular swelling of hepatocytes in males and females. Glutathione S-transferase placental form (GST-P) positive liver foci were observed in the 1600-ppm-exposed females and 3200-ppm-exposed males and females, which are known as a preneoplastic lesion in rat hepatocarcinogenesis. Plasma levels of 1,4-dioxane increased linearly with an increase in the concentrations of exposure to 400 ppm and above. The enlarged nuclei in the nasal epithelia and the GST-P-positive liver foci were discussed in light of the possible development of nasal and hepatic tumors by long-term inhalation exposure to 1,4-dioxane. A lowest-observed-adverse-effect level (LOAEL) was determined at 100 ppm for the nasal endpoint in both male and female rats.

Occurrence of two different types of glutathione S-transferase placental form-positive hepatocytes after a single administration of 2,3,7,8-tetrabromodibenzo-p-dioxin in rats

Occurrence of glutathione S-transferase placental form (GST-P)-positive hepatocytes was examined, using 15 Wistar rats of both sexes each orally administered 2,3,7,8-tetrabromo-dibenzo-p-dioxin (TBDD) by gavage at a single dose of 0, 10, 30, 100 or 300 microg/kg body weight. Liver tissues were stained with anti-GST-P antibody. Two different types of GST-P-positive hepatocytes were found in the TBDD-dosed rat. One type was of the hepatocytes stained homogeneously with anti-GST-P antibody and clearly distinguishable from the surrounding normal tissue. The foci were composed of 2 to 60 hepatocytes exhibiting morphologically focal and clonal proliferation. The GST-P-positive hepatocellular foci occurred at two higher dose levels and only on Day 36 after the single administration. Another type was of the area occupied by the positively but heterogeneously stained hepatocytes appearing predominantly in the centrilobular region, at lower dose levels and persistently on Day 2 through 36. The stained hepatocytes appeared to be neither focally nor clonally proliferating. Females were more susceptible to formation of the two differently stained hepatocytes than males. It is suggested that the GST-P-positive foci represent an early stage of hepatocarcinogenesis, while the GST-P-positive area is associated with the induction of detoxifying Phase II GSTs.

Immunohistochemical evaluation of phosphorylated SMAD2/SMAD3 and the co-activator P300 in human glomerulonephritis: correlation with renal injury

Background: Smad2 and Smad3 are transcription factors that mediate transforming growth factor beta (TGF-β) signals. Upon their activation, phosphorylated Smad2/Smad3 (pSmad2/Smad3), translocate to the nucleus and associate with co-activators such as p300, regulating the transcription of genes that contribute to the fibrotic processes. Methods: We investigated the immunohistochemical expression of pSmad2/Smad3 and the co-activator p300 in 152 renal biopsy specimens from patients with various types of glomerulonephritides (GNs) and in 15 normal kidney specimens. Patients’ clinical data (serum creatinine level and proteinuria) had been collected. Results: There was a dramatic increase in the expression of pSmad2/3 and p300 in all glomerular cell types in all GNs. pSmad2/3 expression was increased in all tubular segments (except for the proximal tubules in nonproliferative GNs), while p300 expression was significantly increased only in the proximal tubular cells in all GNs. Glomerular and tubular pSmad2/Smad3 and p300 were significantly increased in proliferative GNs (compared to the nonproliferative), particularly in the secondary group. The expression profile of p300 correlated positively with the expression of pSmad2/Smad3 in the diseased glomeruli and proximal tubules. pSmad2/3 and p300 were very often detected in segmental hyperplastic lesions, cellular crescents, microadhesions and segmental or global sclerotic areas. Glomerular and proximal tubular pSmad2/Smad3 was positively correlated with serum creatinine levels, while distal and collecting tubular pSmad2/3 and p300 correlated positively with tubular atrophy. Glomerular and proximal tubular pSmad2/3 expression and glomerular p300 expression correlated positively with lupus nephritis activity. Conclusion: Our results suggest that pSmad2/3-p300 pathway may play a pivotal role in the pathogenesis and progression of human glomerulonephritis.

Technical pitfalls potentially affecting diagnoses in immunohistochemistry

Result of the immunohistochemical reactions routinely used in diagnostic surgical pathology should be properly interpreted, since false results, related to technical and interpretative pitfalls may lead to incorrect diagnosis. The main sources of such pitfalls are reviewed, analytically described and related to different steps (fixation, tissue processing and embedding, decalcification, antigen retrieval) which may affect the accuracy of immunohistochemistry. In addition, the presence of endogenous enzyme activity, improper binding of avidin to endogenous biotin, incorrect use of antibodies, chromogen and detection systems, as well as incorrect interpretation may produce unreliable data. The high frequency and extension of such pitfalls make mandatory the use of internal and external controls and adoption of cross-validation programmes. The present study, supported by an extensive review of the related literature, is intended as a guideline leading to proper interpretation of immunohistochemical data, an essential component of the diagnostic process. Experience on the antigen retrieval procedures for different antigens is also presented.

A focus on fixation

Three fixation issues related to immunostaining are discussed here: 1) Generally, a tissue block is fixed, then embedded and sectioned (pre-fixation). The type of fixative applied, crosslinking or coagulating, has an impact on selecting an epitope retrieval method. Individual antigens have a fixation-retrieval characteristic. 2) A long fixation time, especially with crosslinking fixatives, may compromise the result of immunostaining. This negative effect varies among different antigens and can be partially restored by applying a more sensitive/efficient detection system such as tyramide amplification. 3) Sections cut from a fresh frozen tissue block usually are acetone fixed(post-fixation). This was accepted as the "gold standard" for a long time. Post-fixation, however,may have serious consequences for preservation of small peptides leaking from the cut open cells,whereas this is not the case with pre-fixed intact cells. Consequently, the concept of an acetone post-fixed cryostat tissue section as "gold standard" no longer exists and a more appropriate use of the terms immunohistochemistry and immunocytochemistry therefore seems justified. For many antibodies, it is not known whether a formalin fixed, paraffin embedded tissue specimen is appropriate. Suggestions are made for creating a positive control cell block for testing such antibodies.

Multiple immunoenzyme staining: methods and visualizations for the observation with spectral imaging

Several staining concepts and color combinations exist to perform successful double immunoenzyme staining on human tissue specimens. Most of these concepts are based on differences between both primary antibodies: animal species, mouse Ig isotype or IgG subclasses, conjugates, or concentrations. Traditionally, double immunoenzyme staining has used chromogens selected to provide maximum color contrast when observed with the unaided eye. Unfortunately, visually good color combinations always include at least one diffuse chromogen, because of the paucity of appropriate chromogen colors. This situation is drastically changed with the use of spectral imaging, where multicolor microscopy can be unmixed in individual images based on their spectral characteristics. Spectral unmixing can be performed even up to quadruple immunoenzyme staining. This work contains practical suggestions for immunoenzyme double staining procedures for some frequently encountered primary antibody combinations: rabbit-mouse, goat-mouse, mouse-mouse, and rabbit-rabbit. The suggested protocols are all suitable for a classical red-brown color combination plus blue nuclear counterstain that is composed of peroxidase activity (diaminobenzidine tetrahydrochloride), alkaline phosphatase activity (Liquid Permanent Red), and hematoxylin, respectively. Although the red and brown chromogens do not contrast very well visually, they both show a crisp localization and can be perfectly unmixed by spectral imaging.

Thirteen-week inhalation toxicity of carbon tetrachloride in rats and mice

Subchronic toxicity of carbon tetrachloride (CCl4) was examined by inhalation exposure of F344 rats and BDF1 mice of both sexes to 0, 10, 30, 90, 270 or 810 ppm (v/v) CCl4 vapor for 13 wk (6 h/d and 5 d/wk). In the high exposure levels at 270 and 810 ppm, altered cell foci in the livers of both rats and mice, and fibrosis and cirrhosis in the rat liver were observed. Hematoxylin and eosin-stained altered cell foci of rats were recognized as glutathione-S-transferase placental form (GST-P) positive foci, which are preneoplastic lesions of hepatocarcinogenesis. The most sensitive endpoint of CCl4-induced toxicity was fatty change with large droplets in rats of both sexes and male mice, and cytoplasmic globules in male mice, as well as increased relative liver weight in male rats. Those endpoints were manifested at 10 ppm and the LOAEL was determined as 10 ppm for the hepatic endpoints in rats and mice. Enhanced cytolytic release of liver transaminases into plasma in rats and mice and its close association with hepatic collapse in mice were observed at medium and high levels of inhalation exposure. Both CCl4-induced hematotoxicity and nephrotoxicity were observed in both rats and mice, but those toxicities were manifested at higher exposure concentrations than hepatotoxicity. The LOAEL for the hepatic endpoint and the GST-P-stained altered cell foci provide relevant animal data for reconsidering the occupational exposure limit val1ue of 5 ppm for CCl4 and strengthen the evidence of CCl4-induced hepatocarcinogenicity which is used in its carcinogenicity classification.

The contribution of bifunctional SkipDewax pretreatment solution, rabbit monoclonal antibodies, and polymer detection systems in immunohistochemistry

CONTEXT

In immunohistochemistry, nonstandardized antigen retrieval protocols and fluids, poor-quality antibodies, and the presence of endogenous biotin frequently lead to incorrect results. Recently, advanced reagents including bifunctional SkipDewax pretreatment solution (BSPS), rabbit monoclonal (RM) antibodies, and biotin-free polymer detection systems (PDSs) have been developed, which, it is claimed, resolve these problems.

OBJECTIVES

To determine whether BSPS, RM antibodies, and biotin-free PDSs improve the accuracy of immunohistochemistry; to optimize a new protocol consisting of a combination of BSPS, RM antibodies, and PDSs; and to compare it with a conventional protocol.

DESIGN

The efficacies of BSPS, RM antibodies, and PDSs were compared with those of their respective conventional reagents using multitissue spring-roll sections. The new protocol was compared with a conventional protocol using Ki-67 immunostaining of 49 colorectal carcinoma specimens.

RESULTS

For antigen retrieval, BSPS resulted in similar or better tissue staining than an EDTA solution, but the efficacy of BSPS decreased when it was reused. Most RM antibodies resulted in a greater proportion of positive cells than the corresponding non-RM antibodies, which did not produce satisfactory results in the absence of antigen retrieval. The PDSs Bond, ChemMate, and SuperPicture resulted in a high percentage of positive cells, good staining intensities, and low backgrounds. Other PDSs, except that from Ventana, resulted in high backgrounds and false positivity. The new combined protocol resulted in better Ki-67 staining than the conventional assay.

CONCLUSIONS

Bifunctional SkipDewax pretreatment solution, RM antibodies, and PDSs improve staining quality and diagnostic accuracy of immunohistochemistry assays and provide a foundation for standardization.

Noninvasive quantitative assessment of oral tongue cancer by intraoral ultrasonography

BACKGROUND

To assess tissue characterization of oral tongue cancer and prediction of subclinical cervical lymph node metastasis, we investigated whether intraoral ultrasonography could be used in conjunction with a computer-aided diagnosis (CAD) system.

METHODS

The study population comprised 109 patients with presurgical, clinical T1N0 or T2N0 oral tongue squamous cell carcinoma who underwent partial glossectomy. All the patients were examined by preoperative intraoral and postoperative ex vivo ultrasonography. To evaluate the ultrasonic images quantitatively, ultrasonographic parameters from tumor contour features were computed by using the proposed CAD system. The imaging results were correlated with histopathologic findings.

RESULTS

Oral tongue cancer was clearly identified in all patients by intraoral ultrasonography. Ultrasonic images of oral tongue cancer reflected the histopathologic structures. Subclinical cervical lymph node metastasis was predicted by intraoral ultrasonography. In a logistic regression analysis using the proposed CAD system, the diagnostic sensitivity, specificity, and accuracy for prediction of subclinical lymph node metastasis were 87.2%, 84.3%, and 85.3%, respectively.

CONCLUSIONS

Intraoral ultrasonography in conjunction with the proposed CAD system allows tissue characterization and prediction of subclinical cervical lymph node metastasis.

Background Staining of Visualization Systems in Immunohistochemistry

The aim of this study was to evaluate specific immunostaining and background staining in formalin-fixed, paraffin-embedded human tissues with the 2 most frequently used immunohistochemical detection systems, Avidin-Biotin-Peroxidase (ABC) and EnVision+. A series of fixed tissues, including breast, colon, kidney, larynx, liver, lung, ovary, pancreas, prostate, stomach, and tonsil, was used in the study. Three monoclonal antibodies, 1 against a nuclear antigen (Ki-67), 1 against a cytoplasmic antigen (cytokeratin), and 1 against a cytoplasmic and membrane-associated antigen and a polyclonal antibody against a nuclear and cytoplasmic antigen (S-100) were selected for these studies. When the ABC system was applied, immunostaining was performed with and without blocking of endogenous avidin-binding activity. The intensity of specific immunostaining and the percentage of stained cells were comparable for the 2 detection systems. The use of ABC caused widespread cytoplasmic and rare nuclear background staining in a variety of normal and tumor cells. A very strong background staining was observed in colon, gastric mucosa, liver, and kidney. Blocking avidin-binding capacity reduced background staining, but complete blocking was difficult to attain. With the EnVision+ system no background staining occurred. Given the efficiency of the detection, equal for both systems or higher with EnVision+, and the significant background problem with ABC, we advocate the routine use of the EnVision+ system.

Immunohistochemical evaluation of phosphorylated SMAD2/SMAD3 and the co-activator P300 in human glomerulonephritis: correlation with renal injury

BACKGROUND

Smad2 and Smad3 are transcription factors that mediate transforming growth factor beta (TGF-beta) signals. Upon their activation, phosphorylated Smad2/Smad3 (pSmad2/Smad3), translocate to the nucleus and associate with co-activators such as p300, regulating the transcription of genes that contribute to the fibrotic processes.

METHODS

We investigated the immunohistochemical expression of pSmad2/Smad3 and the co-activator p300 in 152 renal biopsy specimens from patients with various types of glomerulonephritides (GNs) and in 15 normal kidney specimens. Patients' clinical data (serum creatinine levels and proteinuria) had been collected.

RESULTS

There was a dramatic increase in the expression of pSmad2/3 and p300 in all glomerular cell types in all GNs. pSmad2/3 expression was increased in all tubular segments (except for the proximal tubules in nonproliferative GNs), while p300 expression was significantly increased only in the proximal tubular cells in all GNs. Glomerular and tubular pSmad2/Smad3 and p300 were significantly increased in proliferative GNs (compared to the nonproliferative), particularly in the secondary group. The expression profile of p300 correlated positively with the expression of pSmad2/Smad3 in the diseased glomeruli and proximal tubules. pSmad2/3 and p300 were very often detected in segmental hyperplastic lesions, cellular crescents, microadhesions and segmental or global sclerotic areas. Glomerular and proximal tubular pSmad2/Smad3 was positively correlated with serum creatinine levels, while distal and collecting tubular pSmad2/3 and p300 correlated positively with tubular atrophy. Glomerular and proximal tubular pSmad2/3 expression and glomerular p300 expression correlated positively with lupus nephritis activity.

CONCLUSION

Our results suggest that pSmad2/3-p300 pathway may play a pivotal role in the pathogenesis and progression of human glomerulonephritis.

A method for immunohistochemical detection of osteogenic markers in undecalcified bone sections

To evaluate the osteogenic potential of novel implant materials, it is important to examine their effect on osteoblastic differentiation. Characterizing the tissue response at the bone-biomaterial interface in vivo at a molecular level would contribute significantly to enhancing our understanding of tissue integration of endosseous implant materials. We describe here a new technique that overcomes difficulties commonly associated with performing immunohistochemistry on undecalcified sawed sections of bone. Sheep mandible specimens were fixed in an ethanol based fixative to maintain adequate antigenicity of the tissue. As a result, it was possible to omit antigen retrieval at high temperature for recovery of antigenicity, and detachment of sections from the slides was avoided. Following dehydration and infiltration, the specimens were embedded in a resin composed of polymethylmethacrylate and polybutylmethacrylate. Polymerization was achieved by adding benzoylperoxide and N,N-dimethyl-toluidine. This resin was selected because it maintained the antigenicity of the tissue, provided adequate properties for cutting 50 microm thick sections, and it facilitated deacrylizing the sawed sections. Acid-resistant acrylic slides were glued to the blocks using an epoxy resin based two-component adhesive to avoid detachment of the slides during the deacrylation procedure. Samples were stained for alkaline phosphatase, type I collagen, osteonectin, osteopontin, osteocalcin and bone sialoprotein. The EnVision + trade mark dextran polymer conjugate two-step visualization system was applied for immunohistochemical detection of these bone matrix proteins. This procedure yielded positive staining for the osteogenic markers in cells and matrix components. The protocol described here facilitates the use of immunohistochemistry on resin embedded sawed sections of bone and provides a convenient and reliable method that can be used routinely for immunohistochemical analysis of hard tissue specimens containing implant materials.

Clinicopathological implications of immunohistochemically demonstrated mucin core protein expression in hepatocellular carcinoma

METHODS

We examined the expression of mucin core protein 1 (MUC1) immunohistochemically in 186 surgical specimens of histopathologically nonmucinous hepatocellular carcinoma (HCC) and compared the clinicopathological features in patients with MUC1-positive HCC (MUC1-positive group) with those in patients with MUC1-negative HCC (MUC1-negative group).

RESULTS

MUC1 immunoreactively was present in 85 of the 186 HCCs. Of the clinicopathological variables examined, the serum concentration of alpha-fetoprotein, tumor differentiation, bile duct invasion, lymph node metastasis, and cytokeratin 19 expression exhibited significant associations with MUC1 expression. Although cumulative and tumor-free survival rates were not different between the two groups, the percentage of patients with first recurrence of HCC in distant organs (distant metastasis) within 2 years after surgery was significantly higher in the MUC1-positive group than in the MUC1-negative group (P = 0.0104). The risk ratio of MUC1 positivity for this type of distant metastasis was 3.156 (95% confidence interval, 1.064-9.358).

CONCLUSIONS

In patients with MUC1-positive HCC, careful follow-up is necessary, not only for intrahepatic recurrence but also for distant metastasis, after the resection of primary HCC.

Comparison of two polymer-based immunohistochemical detection systems: ENVISION+? and ImmPRESS?

The non-specific background reaction produced in avidin-biotin-based immunohistochemistry, particularly after harsh antigen retrieval procedures, has promoted the use of non-avidin-biotin systems, yet there are few reports comparing the performance of non-avidin-biotin, polymer-based methods. In this study we compare two of these methods, ENVISION+trade mark and ImmPRESS, in animal tissues. We examined the immunoreactivity of 18 antigens in formalin-fixed, paraffin-embedded tissues. Antigens were located in the cytoplasmic membrane (CD11d, CD18 and CD79a), cytoplasm (calretinin, COX-1, COX-2, Glut-1, HepPar 1, KIT, Melan A, tryptase and uroplakin III) or nucleus (MUM-1, PGP 9.5 and thyroid transcription factor 1). We also evaluated three infectious agents (Aspergillus, calicivirus and West Nile virus). The staining with ENVISION+ or ImmPRESS was performed simultaneously for each antigen. The intensity of the reaction and background staining were scored. ImmPRESS yielded similar or higher reaction intensity than ENVISION+trade mark in 16/18 antigens. ImmPRESS produced abundant background with the other two antigens (calretinin and COX-2), which hindered interpretation of the specific reaction. The cost of ImmPRESS was 25% lower than for ENVISION+trade mark. Based on these results, ImmPRESS is a good polymer-based detection system for routine immunohistochemistry.

Blood group A and B antigen expression in human kidneys correlated to A1/A2/B, Lewis, and secretor status

BACKGROUND

In the revived interest in crossing ABO barriers in organ transplantation renal A/B antigen expression has been correlated with donor ABO, Lewis, and secretor subtype to predict antigen expression.

METHODS

A/B antigen expression was explored by immunohistochemistry in LD renal biopsies. Donor A1/A2/B, Lewis, and secretor status were determined by serology and polymerase chain reaction.

RESULTS

In the renal vascular bed, three distinct A antigen expression patterns with a major, minor, and minimal staining distribution, and intensity (designated as types 3+, 1+ and (+) respectively) were identified. Type 3+ had a strong A antigen expression in the endothelium of arteries, glomerular/peritubular capillaries and veins. The type 1+ showed an overall weaker antigen expression, whereas type (+) had faint staining of peritubular capillaries only. In all cases, distal tubular epithelium was focally stained, whereas proximal tubules were negative. Type 3+ were all from blood group A1 subtype individuals while A2 cases expressed either a 1+ or (+) pattern. The secretor gene did not appear to influence renal A antigen expression. All B kidneys examined showed a B antigen pattern slightly weaker but otherwise similar to A type 3+.

CONCLUSION

Renal vascular A antigen expression correlates to donor A1/A2 subtypes, whereas B individuals show one singular antigen pattern. From antigen perspective, A1 and B donors are a "major" and A2 individuals a "minor" antigen challenge in ABO-incompatible renal transplantation.

Direct maxacalcitol injection into hyperplastic parathyroids improves skeletal changes in secondary hyperparathyroidism

Direct maxacalcitol (OCT) injection into a parathyroid gland (PTG) ameliorates several important etiologic factors of resistance to medical treatments for secondary hyperparathyroidism (s-HPT): the upregulations of vitamin D receptor (VDR) and Ca-sensing receptor (CaSR) in PTGs and the regression of PTG hyperplasia by the induction of apoptosis. In this study, we evaluated the bone histomorphology on the basis of maintaining these effects in advanced s-HPT. Five/six nephrectomized Sprague-Dawley rats were fed a high-phosphorus and low-calcium diet for 8 weeks. These rats were divided into four treatment groups: (1) basic uremic (at the baseline), (2) direct OCT single injection into PTGs (DI-OCT) followed by OCT intravenous administration for 4 weeks (IV-OCT), (3) direct vehicle injection and IV-OCT, and (4) no treatment for an additional 4 weeks. The effects of these treatments on serum intact-parathyroid hormone (PTH) level, PTG weight, VDR and CaSR expression levels in PTGs, and bone histomorphometric parameters were investigated. In the DI-OCT+IV-OCT group, the significant decrease in serum intact-PTH level was maintained by the following IV-OCT. A significant decrease in PTG weight and the upregulations of VDR and CaSR expression levels in PTGs were also observed. Bone histomorphometric analysis showed significant improvements in osteitis fibrosa in both cancellous and cortical bones. However, these findings were not observed in the other groups. These results suggest that osteitis fibrosa caused by advanced s-HPT can be successfully reversed by a control of PTH at an appropriate level through the improvement of PTG hyperplasia as induced by DI-OCT+IV-OCT.

The immunohistology of CD40 in human oral epithelium in health and disease

BACKGROUND

CD40 has a role in the regulation of immune responses, cell proliferation and migration, and apoptosis. Little is known of its distribution in oral mucosal pathology.

METHODS

Oral keratinocyte lines were tested for CD40 protein by Western blotting. Immunohistochemistry was used to stain paraffin sections of oral mucosa in health and in inflammatory, reactive, dysplastic and malignant disease.

RESULTS

Western blotting confirmed the presence of CD40 in oral keratinocytes. CD40 was generally expressed by keratinocytes in the basal layer, with variable parabasal expression. Langerhans cells also stained positively. Expression was lost in nine of 33 (27%) epithelial dysplasias, seven of which were severe. Eighty-one percent of well, 69% of moderately and 50% of poorly differentiated oral squamous cell carcinomas (OSCC) expressed CD40. Overall, 45 of 65 (69%) OSCC were positive. The pattern of expression was unrelated to tumour differentiation.

CONCLUSION

CD40 expression by basal and parabasal oral keratinocytes is physiological. Expression is lost in approximately one-third of oral epithelial dysplasias and OSCC. The significance of such loss remains unknown, but may be related to immunological or other abnormalities of keratinocyte homeostasis.

Technical aspects of immunohistochemistry

Immunohistochemistry is an integral technique in many veterinary laboratories for diagnostic and research purposes. In the last decade, the ability to detect antigens (Ags) in tissue sections has improved dramatically, mainly by countering the deleterious effects of formaldehyde with antigen retrieval (AR) and increasing sensitivity of the detection systems. In this review, I address these topics and provide an overview of technical aspects of immunohistochemistry, including those related to antibodies (Abs) and Ags, fixation, AR, detection methods, background, and troubleshooting. Microarray technology and the use of rabbit monoclonal Abs in immunohistochemistry are also discussed.

Thirteen-week inhalation toxicity of p-dichlorobenzene in mice and rats

Subchronic inhalation toxicity of p-dichlorobenzene (p-DCB) was examined by exposing BDF1 mice and F344 rats of both sexes (6 h/d and 5 d/wk) to inhalation of 25, 55, 120, 270 or 600 ppm (v/v) p-DCB vapor for 13 wk. The exposure to p-DCB vapor retarded the growth rate in the male mice, and induced hepatotoxicity in the mice and rats of both sexes and renal and hematological toxicity in the male rats. Hepatotoxicity was characterized by increased liver weight, hepatocellular hypertrophy, and increased serum levels of total cholesterol. Liver necrosis and increased serum levels of AST and ALT were observed in the exposed mice, whereas these changes, which indicate hepatocellular death, did not occur in any of the exposed rats. p-DCB-induced renal lesions occurred only in the male rats. Hyaline droplets were observed in the proximal tubular epithelial cells, and were stained positively with anti-alpha2u-globulin, suggesting excessive accumulation of alpha2u-globulin in the epithelial cells. Granular casts were formed in the tubular lumen, resulting from the necrotic desquamation of the renal tubular epithelium. Papillary mineralization in the renal pelvis and increased serum levels of BUN and creatinine were noted. These renal changes indicated alpha2u-globulin nephropathy. Decreases in red blood cell counts, hemoglobin concentration, hematocrit and mean corpuscular volume and increased spleen weight occurred in the exposed male rats. The NOAEL was 120 ppm for the hepatic endpoint in mice and for the renal endpoint in rats. The maximum tolerated dose for a 2-yr bioassay inhalation study of rodent carcinogenicity was estimated to be 300 ppm, based on the present results.

Thirteen-week oral toxicity study of 1,4-dichloro-2-nitrobenzene in rats and mice

Subchronic toxicity of 1,4-dichloro-2-nitrobenzene (DCNB) was examined by feeding F344 rats and BDF mice of both sexes a diet containing 1,481, 2,222, 3,333, 5,000 or 7,500 ppm DCNB (w/w) for 13 wk. Oral administration of DCNB in feed to rats and mice retarded growth rates and induced subchronic toxicity affecting the liver, kidney, testes and blood. Liver and kidney were most responsive to DCNB. BMDL10 values for relative liver weight were 12.0 and 22.6 mg/kg/d for male and female rats, respectively, and 88.7 and 94.4 mg/kg/d for male and female mice, respectively. Increased liver weights and centrilobular hypertrophy of hepatocytes were observed in the DCNB-fed rats and mice of both sexes. Both increased serum activities of AST and ALT and liver necrosis occurred in the DCNB-fed mice. Increased incidences of hyaline droplets and granular casts in the proximal renal tubules were observed only in the DCNB-fed male rats, indicating alpha2v-globulin nephropathy. Eosinophilic droplets in the renal tubular cells and increased BUN concentrations occurred in the DCNB-fed female rats. DCNB-induced testicular and hematologic changes were noted in rats and mice. On the basis of these results, the highest dose level for the 2-yr bioassay study of rodent carcinogenicity was determined to be 2,000 ppm.

Two-week oral toxicity study of 1,4-Dichloro-2-nitrobenzene in rats and mice

Subacute toxicity of 1,4-dichloro-2-nitrobenzene (DCNB) was examined by feeding F344 rats and BDF1 mice of both sexes a diet containing DCNB at 625, 1250, 2500, 5000 or 10,000 ppm (w/w) for 2 weeks. All DCNB-fed rats survived to the end of the 2-week administration period, but 2 male and 6 female mice fed 10,000 ppm died during this period. The subacute toxicity was characterized by lesions affecting the liver, kidney, testis and hematopoietic system. The liver was the most responsive to DCNB, as evidenced by a dose-related increase in relative liver weight in rats and mice and centrilobular hypertrophy of hepatocytes in mice. An alteration in liver-associated lipid metabolism was suggested from the concomitant increases in serum concentrations of total cholesterol and phospholipid. A lower confidence limit of the benchmark dose yielding the response with 10% extra risk (BMDL10) for the relative liver weight indicated that rats were more responsive to DCNB than mice. The kidney lesion was characterized by alpha2upsilon-globulin-accumulated hyaline droplets in the renal tubular epithelial cells only in male rats, as indicated by positive anti-alpha2upsilon-globulin immunohistochemical staining. Testicular and hematopoietic lesions appeared at higher dose levels than did the liver and kidney lesions.

Immunoperoxidase versus immunofluorescence in the assessment of human renal biopsies

BACKGROUND

For half a century, immunofluorescence (IF) on frozen sections has been the gold standard for immunohistochemical evaluation of renal biopsy specimens. In routine diagnostic immunohistopathologic evaluation, traditional IF has been replaced to a large extent by immunoperoxidase (IP) methods applied to paraffin sections of formaldehyde-fixed tissue. This is caused in part by the practical disadvantages inherent in the IF method, eg, separate tissue specimen and handling, UV microscopy, fading and impermanence of the label-making archiving, and difficult later investigation. Our aim for the present study is to evaluate IP as an alternative to IF in the diagnostic assessment of renal biopsy specimens.

METHODS

Proteolytic antigen retrieval, antibodies effective on deparaffinized sections, a sensitive detection system (Dako EnVision HRP; Dako, Copenhagen, Denmark), and a standardized and rigorously controlled procedure were applied to a series of renal biopsy specimens (n = 81) previously classified by means of light microscopy (LM) and IF. Staining for immunoglobulin G (IgG), IgA, IgM, C1q, and C3c were recorded as positive or negative for IF and IP in paired proportions, presuming that IF was the test standard.

RESULTS

Concordant observations were 71% for all (282 of 398 observations), 82% for IgG (65 of 79 observations), and 89% for IgA (72 of 81 observations). The majority of discordant observations (74 of 116 observations) were positive by means of IP, with mesangial deposits of IgM and C1q that were not found by IF. Statistically, there was no significant difference in outcomes between IF and IP for IgG, IgA, and C3c ( P > 0.2). In addition, IP staining allowed simultaneous evaluation of tissue by LM and therefore correlation between tissue structure and immune deposits not readily attained by IF.

CONCLUSION

In the present study, it is documented that for the detection of IgG, IgA, and C3c, IP applied to protease-digested deparaffinized sections of formaldehyde-fixed renal tissue is, with few exceptions, equal to IF on frozen sections. The EnVision HRP method used here is several times more effective in terms of primary antibody dilution than earlier existing IP methods, and because the avidin-biotin system is not involved, very little nonspecific background staining will occur. Discordant observations (116 of 398 observations; 29%) were in the majority (91 of 116 observations) due to positive IP findings of IgM and C1q, which deserve additional investigation.

Acute stress reduces intraparenchymal lung natural killer cells via beta-adrenergic stimulation

There are lines of evidence that natural killer (NK) cells are sensitive to physical and psychological stress. Alterations in the immune system including NK cells are known to differ among tissues and organs. The effect of stress on the lung immune system, however, has not been well documented in spite of the fact that the lungs always confront viral or bacterial attacks as well as tumour cell metastasis. In this study, we intended to investigate the effect of restraint stress on lung lymphocytes including NK cells. C57BL/6 mice were exposed to 2 h restraint stress. The concentration of plasma epinephrine significantly rose immediately after the release from restraint as compared to home-cage control mice. Flow cytometric analysis revealed that the numbers of most lymphocyte subsets including NK cells were decreased in the lungs and blood but not in the spleen, immediately after restraint stress. Immunohistochemical examination revealed that the number of NK cells was decreased in the intraparenchymal region of the lungs, while the number of alveolar macrophages did not change. The decrease in the number of NK cells in the lungs and blood was reversed by the administration of propranolol, a nonselective beta adrenergic antagonist. Taken together, our findings suggest that acute stress reduces the number of intraparenchymal lung NK cells via activation of beta adrenergic receptors.

Pathogenicity by parenteral injection of fowl adenovirus isolated from gizzard erosion and resistance to reinfection in adenoviral gizzard erosion in chickens

The pathogenicity of a serotype-1 fowl adenovirus (FAV-99ZH), which causes adenoviral gizzard erosion by oral inoculation in chickens, was investigated in specific pathogen-free white leghorn chickens. In trial 1, 14 chickens were inoculated intravenously with the virus at 21 days of age and euthanatized for necropsy within 1-14 days of inoculation. Gizzard erosion was grossly observed from day 7 postinoculation (PI), and histologically, FAV-99ZH antigen-positive, basophilic intranuclear inclusion bodies were seen in the gizzard lesions from day 7 to 11 PI. Necrotizing pancreatitis, and cholecystitis and cholangitis associated with the inclusions were observed from day 3 to 14 PI (pancreatitis) and from day 5 to 9 PI (cholecystitis and cholangitis), respectively. The inclusions were also observed in the epithelial cells of the cecal tonsils from day 3 to 5 PI. The virus was recovered from samples of the lesions. It was revealed that FAV-99ZH causes not only gizzard erosion but also pancreatitis, cholecystitis, and cholangitis by intravenous inoculation in chickens. In trial 2, 10 chickens were inoculated orally with the virus twice, at 13 and 36 days of age, and euthanatized for necropsy within 4-17 days after reinfection. Macroscopically, focal gizzard lesions were observed; however, neither necrosis nor inclusions were observed by microscopy. Moreover, FAV was not recovered from the gizzard or rectum of any of the chickens at necropsy. This suggests that the gizzard lesions occurred as a result of the primary infection, and that the chickens were able to resist reinfection.

Carcinoma ex-pleomorphic adenoma of the breast. Report of three cases suggesting a relationship to metaplastic carcinoma of matrix-producing type

Three cases of carcinoma ex-pleomorphic adenoma of the breast are reported. Patients were 82, 60 and 56 years old and presented with a breast lump. All tumours showed areas of pleomorphic adenoma adjacent to typical areas of malignant transformation. These cases add to the spectrum of tumours shared by breast and salivary gland. The relationship between these neoplasms and metaplastic carcinoma of matrix-producing type is discussed.

Biochemical and Cellular Effects of Direct Maxacalcitol Injection into Parathyroid Gland in Uremic Rats

The most important etiological factors of resistance to medical treatments for secondary hyperparathyroidism are the decreased contents of the vitamin D receptor (VDR) and Ca-sensing receptor (CaSR) in parathyroid cells and a severely swollen parathyroid gland (PTG) as a result of hyperplasia. The effects of direct maxacalcitol (OCT) injection into PTG in terms of these factors were investigated in this study. The PTG of Sprague-Dawley rats that were 5/6 nephrectomized and fed a high-phosphate diet were treated by a direct injection of OCT (DI-OCT) or vehicle (DI-vehicle). The changes in serum intact parathyroid hormone (PTH), Ca(2+), and phosphorus levels, in VDR and CaSR expression levels in parathyroid cells, and in Ca(2+)-PTH curves were examined. Apoptosis was analyzed by the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling method and DNA electrophoresis for PTG. DI-OCT markedly decreased serum intact PTH level, and a significant difference in this level between DI-OCT and DI-vehicle was observed. However, serum Ca(2+) and phosphorus levels did not changed markedly in both groups. The upregulations of both VDR and CaSR, the clear shift to the left downward in the Ca(2+)-PTH curve, and the induction of apoptosis after DI-OCT were observed. These findings were not observed in the DI-vehicle-treated rats. Moreover, these effects of DI-OCT were confirmed by the DI-OCT into one PTG and DI-vehicle alone into another PTG in the same rat. DI-OCT may introduce simultaneous VDR and CaSR upregulations and the regression of hyperplastic PTG, and these effects may provide a strategy for strongly suppressing PTH levels in very severe secondary hyperparathyroidism.

CD147 and matrix metalloproteinase-2 protein expression as significant prognostic factors in esophageal squamous cell carcinoma

BACKGROUND

The authors investigated whether the presence of matrix metalloproteinase-2 (MMP-2) and its inducer, CD147, in cancerous esophageal lesions and surrounding tissue might help to predict patient prognosis.

METHODS

Tissue samples from 101 patients with esophageal squamous cell carcinoma were stained with anti-CD147 and anti-MMP-2 antibodies for immunohistochemical analysis.

RESULTS

CD147 was expressed in cancerous and dysplastic lesions, but not in normal tissue. In contrast, MMP-2 was detected mainly in normal interstitial tissue adjacent to cancerous lesions, but it was detected also in cancerous lesions in some patients. Pathologic findings demonstrated that the intensity of MMP-2 staining in normal tissue was associated positively with the depth of tumor infiltration and the stage of disease, whereas MMP-2 staining in cancerous tissue was associated positively with vascular and lymphatic vessel invasion as well as with immature differentiation of cancer cells. Using a proportional hazard model, including information on CD147 staining patterns within cancerous lesions along with clinical cancer staging, improved the accuracy of predicting patient prognosis.

CONCLUSIONS

These results suggested that measurement of CD147 and MMP-2 expression with simple immunohistochemical staining may enhance further the understanding of the pathophysiology of invading tumor cells and, when used in combination with cancer staging, may increase the ability of investigators to predict prognosis in patients with esophageal squamous cell carcinoma.

Decreased expression of B7 costimulatory molecules and major histocompatibility complex class-I in human hepatocellular carcinoma

BACKGROUND AND AIM

We analyzed the expression of antigen-processing and antigen-presenting molecules in surgically resected fresh samples of human hepatocellular carcinoma (HCC) tissue to elucidate a mechanism of immune escape. We also examined the expression of interleukin (IL)-10 protein, which might act to downregulate expression of antigen-processing and antigen-presenting molecules.

METHODS

Twenty-eight HCC samples obtained by surgical resection were analyzed for the expression of beta2-microglobulin, heat-shock protein (HSP)-70, human leukocyte antigen (HLA) class-I, CD80 (B7-1), CD86 (B7-2) and IL-10 by immunostaining.

RESULTS

Beta2-microglobulin and HSP-70 were preserved in all samples. In contrast, the expression of HLA class-I molecules was significantly reduced according to lowering in the histological grading of tumor differentiation (P = 0.024). Furthermore, B7-1 and B7-2 expression was reduced in tumor cells compared with corresponding areas of liver tissue without malignant involvement irrespective of the histological grading of tumors (21% and 36%, respectively). Although IL-10 protein was expressed in 54% of HCC, no relationship between the expression of IL-10 and downregulation of B7-1, B7-2, and HLA class-I was evident.

CONCLUSION

These findings suggest the potential role of B7 co-stimulatory molecules and HLA class-I molecules in facilitating HCC escape from immune surveillance without the involvement of IL-10.

Antitumor Activity of Gefitinib in Malignant Rhabdoid Tumor Cells In vitro and In vivo

PURPOSE

Malignant rhabdoid tumor (MRT) is a rare and highly aggressive neoplasm of young children. Current treatments have had only limited success. Epidermal growth factor receptor (EGFR) was found recently to be expressed on MRT cell lines. Gefitinib (trade name Iressa) is an oral and selective EGFR-tyrosine kinase inhibitor and has been demonstrated to be effective in inhibiting the proliferation of cancer cells in vivo as well as in clinical trials. This encouraged us to examine the antitumor effects of gefitinib on MRT cells in vitro and in vivo.

EXPERIMENTAL DESIGN

The expression of EGFR in two MRT tumors and two MRT cell lines (MP-MRT-AN and KP-MRT-NS), established from these two tumor tissues, was examined by immunohistochemistry, immunofluorescence, and immunoblot. The effect of gefitinib on EGFR phosphorylation was examined by immunoblot. The effects of gefitinib on cell growth and apoptosis were examined by cell growth assay and terminal deoxynucleotidyl transferase-mediated nick end labeling assay. The in vivo effect of gefitinib was assessed in athymic mice that had been xenografted with MRT cells.

RESULTS

The expression of EGFR was detected in both tumor tissues and cell lines. Gefitinib inhibited EGFR-phosphorylation (IC(50) < 0.1 micromol/L) and in vitro cell growth (IC(50) = approximately 10-12 micromol/L), and a high concentration of gefitinib (20 micromol/L) induced apoptosis in vitro (MP-MRT-AN, 42.9% and KP-MRT-NS, 47.2%). Furthermore, gefitinib at 150 mg/kg had a cytostatic effect on established MRT xenografts (MP-MRT-AN, P = 0.039 and 0.0014; and KP-MRT-NS, P = 0.048 and 0.0086).

CONCLUSIONS

Our results demonstrate that gefitinib has antitumor effects in MRT cells in vitro and in vivo and, thus, has promise as a novel and therapeutic strategy for MRT.

Septicaemia and arthritis in pigs experimentally infected with Pasteurella multocida capsular serotype A

Twenty-five caesarean-derived, colostrum-deprived (CDCD) pigs and 18 specific pathogen-free pigs, aged 8 to 14 weeks, were inoculated intranasally or intratracheally with Pasteurella multocida capsular serotype A, isolated from a severe pneumonic lesion in a growing pig. The pigs were killed for necropsy on day 6 or 14 post-inoculation (PI) or, in the case of the only fatally infected animal, examined at the time of death. One CDCD pig, inoculated intratracheally with 5 ml of a bacterial suspension containing 1.7x10(9) colony-forming-units/ml, died of septicaemia on day 1 PI. Histological lesions such as severe pleuropneumonia, thrombi in glomerular capillaries, haemorrhage of the spleen, and abscesses in the tonsillar crypts were observed. The organism was recovered from a number of sites and its antigens were detected immunohistochemically in the pneumonic lesions, blood vessels of the tissues, and tonsillar crypts in the dead pig. Pneumonia, pleural adhesions and suppurative arthritis in the extremital joints were observed grossly in 3/29, 8/29 and 7/29 intratracheally inoculated pigs, respectively. In intranasally inoculated pigs, no macroscopical abnormalities were seen; histologically, however, exudative bronchopneumonia and fibrinous pleurisy were observed in 9/14 and 4/14 pigs, respectively. No significant changes were seen in the tissues of uninfected control pigs. The organism was recovered from the lesions and P. multocida type A antigen was demonstrated immunohistochemically. The organism was rarely recovered from the liver, spleen or lymph nodes (bronchopulmonary or mesenteric). The results suggest that P. multocida capsular serotype A alone can cause not only pneumonia in pigs but also septicaemia or arthritis.

Comparison of Immunoexpression of 2 Antibodies for Estrogen Receptors (1D5 and 6F11) in Breast Carcinomas Using Different Antigen Retrieval and Detection Methods

The importance of in situ immunodetection of hormone receptors for therapy planning and prognostic evaluation in patients with breast carcinoma is well established. Sensitive detection methods are of utmost importance, especially in poorly fixed tissues, which are not uncommon in routine pathologic practice. The purpose of the present study is to compare immunoexpression of estrogen receptors in 20 cases of invasive ductal carcinoma using two antibodies, 1D5 and 6F11, and to verify the effect of different antigen retrieval solutions and detection systems. Immunoperoxidase was performed on paraffin sections using 1D5 and 6F11 as primary antibodies. Heat-induced antigen retrieval was performed using citrate buffer (pH 6.0) or Tris-EDTA buffer (pH 8.9). Detection was achieved using the following systems: EnVision, EnVision Plus, and labeled streptavidin-biotin peroxidase complex. Reaction was semiquantified from 0 to 4. There were no differences between the two markers, 1D5 and 6F11, except when 6F11 was used with EnVision and citrate buffer, in which case weaker reactivity was observed. Only in this combination (6F11/EnVision) was EDTA buffer significantly better than citrate. Labeled streptavidin-biotin peroxidase complex presented the best results, followed by EnVision Plus.

Chronic Renal Failure Accelerates Atherogenesis in Apolipoprotein E–Deficient Mice

ABSTRACT. Cardiovascular mortality is 10 to 20 times increased in patients with chronic renal failure (CRF). Risk factors for atherosclerosis are abundant in patients with CRF. However, the pathogenesis of cardiovascular disease in CRF remains to be elucidated. The effect of CRF on the development of atherosclerosis in apolipoprotein E–deficient male mice was examined. Seven-week-old mice underwent 5/6 nephrectomy (CRF, n = 28), unilateral nephrectomy (UNX, n = 24), or no surgery (n = 23). Twenty-two weeks later, CRF mice showed increased aortic plaque area fraction (0.266 ± 0.033 versus 0.045 ± 0.006; P < 0.001), aortic cholesterol content (535 ± 62 versus 100 ± 9 nmol/cm2 intimal surface area; P < 0.001), and aortic root plaque area (205,296 ± 22,098 versus 143,662 ± 13,302 μm2; P < 0.05) as compared with no-surgery mice; UNX mice showed intermediate values. The plaques from uremic mice contained CD11b-positive macrophages and showed strong staining for nitrotyrosine. Systolic BP and plasma homocysteine concentrations were similar in uremic and nonuremic mice. Plasma urea and cholesterol concentrations were elevated 2.6-fold (P < 0.001) and 1.5-fold (P < 0.001) in CRF compared with no-surgery mice. Both variables correlated with aortic plaque area fraction (r2 = 0.5, P < 0.001 and r2 = 0.3, P < 0.001, respectively) and with each other (r2 = 0.5, P < 0.001). On multiple linear regression analysis, only plasma urea was a significant predictor of aortic plaque area fraction. In conclusion, the present findings suggest that uremia markedly accelerates atherogenesis in apolipoprotein E–deficient mice. This effect could not be fully explained by changes in BP, plasma homocysteine levels, or total plasma cholesterol concentrations. Thus, the CRF apolipoprotein E–deficient mouse is a new model for studying the pathogenesis of accelerated atherosclerosis in uremia. E-mail: susannebro@dadlnet.dk

Biologic degeneration of vein grafts after thrombotic occlusion: thrombectomy within 3 days results in better indices of viability

OBJECTIVES

To clarify the mechanism for poor patency of vein grafts after thrombectomy and the time limit for successful salvage operation, we investigated the time course of biologic degenerative changes in thrombosed vein grafts. Materials and methods The right femoral artery was replaced with a femoral vein graft in 25 mongrel dogs. After 3 months, grafts were explanted in 5 dogs (control grafts), and the remaining 20 dogs underwent femoral artery ligation to create a thrombosed graft. Of the 20 grafts, 5 were explanted at 3 days after ligation (group I-3) and 5 were explanted at 5 days after ligation (group I-5). Of the remaining 10 grafts, 5 underwent thrombectomy at 3 days after ligation (group II-3) and 5 underwent thrombectomy at 5 days after ligation, and were reimplanted into the left femoral artery, then explanted 28 days after reimplantation. The grafts were assessed with immunohistochemistry and prostaglandin (PG) I(2) assay (6-keto-PGI(1alpha)).

RESULTS

Of the 25 grafts, occlusion recurred in 3 in group II-5 within 28 days after reimplantation. There were significant differences between group I-5 and group I-3 or control grafts for percentage of areas positive for alpha-actin, total number of cells per field, and proliferating cell nuclear antigen (PCNA)-positive cells in layer of thickened intima and atrophied media (I/M), and for total cell and PCNA- positive cell numbers per field in the adventitia. Mean 6-ketoPGF(1alpha) was 40 +/- 14.1 pg/mg/min in control dogs, 84 +/- 18.9 pg/mg/min in group I-3, and 15.4 +/- 7.7 pg/mg/min in group I-5, demonstrating a significant reduction in group I-5 (P =.009).

CONCLUSION

Graft wall cell viability and PGI(2) production in thrombosed vein grafts are well preserved for up to 3 days. Therefore graft salvage operations no later than 3 days after thrombotic occlusion may provide acceptable long-term patency of salvaged grafts.

Endothelin protein expression as a significant prognostic factor in oesophageal squamous cell carcinoma

The aim of this study was to investigate if the expression of endothelin (ET), a vasoactive peptide, in cancerous oesophageal lesions, adjacent dysplastic tissue and normal mucosa might be prognostic. Tissue samples from a total of 101 patients with oesophageal squamous cell carcinoma were obtained and stained with ET antibody in an immunohistochemical analysis. High staining levels of ET within normal mucosa were related to lymph vessel invasion, regional lymph node metastasis and distant metastasis, as well as a reduced relapse-free survival (log-rank test; P=0.0066). After adjustment for several histological prognostic risk factors and each component of the TNM classification system, high ET expression within dysplastic tissue more than doubled the hazard ratio of relapse with significant model improvement. These results suggest that, in addition to known histological risk factors and TNM classification criteria, measurement of ET expression with a simple immunohistochemical analysis might further help in predicting the prognosis of patients with oesophageal squamous cell carcinoma.

Angiomyolipoma and PEComa are immunoreactive for MyoD1 in cell cytoplasmic staining pattern

The family of tumors derived from mesenchymal perivascular epithelioid cells (so-called PEComas) includes angiomyolipoma, lymphangioleiomyomatosis, clear cell sugar tumor of the lung, clear cell myomelanocytic tumor of ligamentum teres/falciform ligament, and abdominopelvic sarcoma of perivascular epithelioid cells. These tumors were characterized by coexpression of melanocytic (HMB-45) and muscle markers. MyoD1 transcription factor has crucial role in commitment and differentiation of mesenchymal progenitor cells to myogenic lineage. Antibodies to MyoD1 protein (nuclear immunoreactivity) have been shown highly valuable adjuncts in the diagnosis of rhabdomyosarcomas. To evaluate expression of the transcription factor MyoD1 in PEComas, we performed immunohistochemistry. Monoclonal antibody 5.8A for MyoD1 was used on a series of cases of formalin-fixed, paraffin-embedded angiomyolipoma (n = 19), lymphangioleiomyomatosis (n = 3), clear cell sugar tumor of the lung (n = 1), and abdominopelvic sarcoma of perivascular epithelioid cells (n = 2). All cases showed strong granular immunostaining in the tumor cell cytoplasm with the anti-MyoD1 antibody. Cytoplasmic reactivity was noted in the spindle cells, fat cells, and epithelioid cells. Nuclei were negative in all tumors studied, and a clean background was obtained. Several normal and neoplastic human tissues have also been immunostained for MyoD1 without any positive cytoplasmic staining, with the exception of 2 alveolar soft part sarcomas. Cytoplasmic immunostaining with monoclonal antibody 5.8A for MyoD1 in PEComas may correspond to cross-reactivity with an undetermined cytoplasmic protein. Great caution should be exercised in interpreting the immunostaining results with anti-MyoD1 antibody 5.8A.

Adenoviral gizzard erosion in commercial broiler chickens

Pathologic and immunohistochemical changes caused by group I of the fowl adenovirus (FAV) serotype-1 99ZH strain, isolated from broiler chickens exhibiting gizzard erosion, were investigated in commercial broiler chickens. One hundred twenty-two chickens were inoculated with the strain by both oral and ocular routes at 1, 3, or 5 weeks of age and euthanatized for necropsy within 4-18 days of inoculation. Focal gizzard erosions were observed in the inoculated chickens of each age group. A histologically degenerative koilin layer, necrotic mucosa, intranuclear inclusion bodies in the glandular epithelial cells, inflammatory cell infiltrations in the lamina propria, submucosa, and a muscle layer were seen in the gizzards. Immunohistochemical staining showed evidence of FAV antigens in the intranuclear inclusion bodies. These findings were recognized regardless of their maternal antibody levels for FAV serotype-1. Gizzard lesions appeared later in the lower-dose-inoculated chickens than in the higher-dose-inoculated chickens. Numerous CD3-positive cells and IgY-positive plasma cells were seen in the gizzard lesions. In 5-week-old chickens the heterophil infiltrations in the lesions were milder than in younger chickens. Intranuclear inclusion bodies also were observed in the epithelial cells of the ileum or cecal tonsils of some chickens. Thus, this study shows that FAV-99ZH causes adenoviral gizzard erosion in broiler chickens without hepatic or pancreatic lesions and that cell infiltration is more severe than in dietary gizzard erosions.

Immunohistochemical expression of receptor-tyrosine kinase c-kit protein in invasive ductal carcinoma of the pancreas

The expression of receptor tyrosine kinase c-kit and its biologic significance in pancreatic cancer are unclear. We studied the expression of c-kit protein (c-KIT) in resectable invasive ductal carcinomas (IDCs) of the pancreas, in order to assess whether a selective c-kit inhibitor, STI571 (Glivec), may be applied for the treatment of pancreatic IDCs. This study included 72 pancreatic IDC patients who received a pancreatectomy between 1982 and 2002. The expression of c-KIT was analyzed retrospectively by immunohistochemistry. c-KIT was expressed in 78% (56/72) of the pancreatic IDCs. c-KIT expression did not correlate with any clinicopathological factor of pancreatic IDC and c-KIT expression had no significant influence on the survival of the patients. The survival rate of the adjuvant chemotherapy (ACT) (+) group was significantly higher than that of the ACT (-) group, but c-KIT expression had no significant effects on the efficacy of the ACT. Multivariate analysis indicated that the pTNM stage, grade and ACT were all significant variables for survival in IDCs overall. As c-KIT was expressed in 78% of the pancreatic IDCs, it suggests that STI571 may be a beneficial agent for chemotherapy against human pancreatic IDCs.