PAS and GMS utility in dermatopathology: Review of the current medical literature.

The American Society of Dermatopathology has established an Appropriate Use Criteria (AUC) Committee with the intention of establishing evidence-based recommendations regarding the appropriateness of various ancillary tests commonly utilized by dermatopathologists. Periodic acid Schiff (PAS) and Grocott (or Gomori) methenamine silver (GMS) stains represent some of the most commonly employed ancillary tests in dermatopathology. The utility of these tests was targeted for evaluation by the AUC. This literature review represents a comprehensive evaluation of available evidence for the utility of PAS and/or GMS staining of skin and nail biopsies. In concert with expert opinion, these data will be incorporated into future recommendations by the AUC for PAS and GMS staining in routine dermatopathology practice.

Estudo da morfologia e status oxidativo em rim de ratos com nefropatia isquêmica após tratamento com células-tronco mesenquimais de tecido adiposo / Study of morphology and oxidative status in kidney of rats with ischemic nephropathy after treatment with adipose tissue mesenchymal stem cells

A nefropatia isquêmica é uma doença renal crônica provocada pela redução do fluxo sanguíneo renal que pode progredir para a doença renal terminal, cujo tratamentos disponíveis se baseiam em terapias substitutivas da função renal, como diálise ou transplante renal. No entanto, devido ao alto custo dos tratamentos e a carência de órgãos, se faz necessária a busca por novas terapias, como as células-tronco (CT). Apesar do potencial terapêutico das CT em doenças crônicas, não está claro se essas células mantêm seus efeitos benéficos em órgãos lesionados por tempo prolongado. O objetivo desse estudo foi avaliar os efeitos precoces e tardios do tratamento com células-tronco adiposas (CTA) sobre a morfologia e o status oxidativo em rins de ratos com nefropatia isquêmica. A isquemia renal foi induzida pelo modelo 2rins-1clip (2R1C) e, depois de um mês da clipagem da artéria renal, foram injetadas 106 células-tronco na região subscapsular do rim afetado. Após 15 e 30 dias da injeção das CTA, a morfologia renal foi verificada por meio da análise macroscópica, microscópica e ultraestrutural. Além disso, o status oxidativo foi avaliado no tecido renal através da mensuração da atividade das enzimas antioxidantes catalase e glutationa peroxidase; e de marcadores biológicos de dano oxidativo, como proteínas carboniladas, 3-Nitrotirosina e 4-Hidroxinonenal. Por imunoperoxidase foi possível localizar as células-tronco adiposas GFP+ foram rastreadas e encontradas tanto 15 dias, quanto 30 dias após a injeção na região subcapsular. A restauração da arquitetura renal foi evidenciada 15d após o uso das células, onde detectamos redução na deposição de fibras colágenas no parênquima renal, o que não foi observado 30d após o uso das células. Os resultados também foram confirmados através da análise da ultraestrutura renal que mostraram restauração da arquitetura renal no grupo de 15d, não evidenciada no grupo de 30d. Quanto a análise do status oxidativo, somente os animais com nefropatia isquêmica mais prolongada apresentaram estresse oxidativo com redução da atividade da enzima antioxidante catalase no tecido renal. Além disso, foi observado dano proteico e lipídico, sem melhora dessa condição nos animais 30d após o tratamento com as células-tronco. No modelo de nefropatia isquêmica avaliado, o tratamento com CTA mostrou benefícios na morfologia renal a curto prazo, mas não tardiamente, apesar da permanência dessas células no tecido. Acreditamos que o estresse oxidativo, evidenciado somente no tecido renal com isquemia mais prolongada, possa ter dificultado a ação das células-tronco, contribuindo para tais achados. Esses resultados abrem perspectivas para o aprofundamento do estudo quanto à caracterização dos mecanimos de ação das CTA nas respostas anti-fibrogênicas, assim como o estabelecimento do número, frequência, vias de administração e melhor momento para uso dessas células no tratamento de doenças renais crônicas.

Ischemic nephropathy is a chronic kidney disease caused by reduced kidney blood flow that can progress to end stage kidney disease, whose available treatments are based on kidney function replacement therapies, such as dialysis or kidney transplantation. However, due to the high cost of treatments and the lack of organs, it is necessary to search for new therapies, such as stem cells (SC). Despite the therapeutic potential of SC in chronic diseases, it is unclear whether these cells maintain their beneficial effects on injured organs for a long time. The aim of this study was to evaluate the early and late effects of adipose-derived stem cells (ADSC) treatment on the morphology and oxidative status in kidneys of rats with ischemic nephropathy. Renal ischemia was induced by the 2kidneys-1clip (2K1C) model and, after a month of clipping the renal artery, 106 stem cells were injected into the subscapsular region of the affected kidney. After 15 and 30 days of ADSC injection, renal morphology was verified by macroscopic, microscopic, and ultrastructural analysis. In addition, oxidative status was assessed in renal tissue by measuring the activity of the antioxidant enzymes catalase and glutathione peroxidase; and biological markers of oxidative damage, such as carbonylated proteins, 3-nitrotyrosine and 4-hydroxynonenal. By immunoperoxidase, it was possible to locate GFP + adipose-derived stem cells that were tracked and found both 15 days and 30 days after injection in the subcapsular region. The restoration of the renal architecture was evidenced 15d after the use of the cells, where we detected a reduction in the deposition of collagen fibers in the renal parenchyma, which was not observed 30d after the use of the cells. The results were also confirmed by analyzing the renal ultrastructure, which showed restoration of the renal architecture in the 15d group, not evidenced in the 30d group. Regarding the analysis of oxidative status, only animals with more prolonged ischemic nephropathy presented oxidative stress with reduced activity of the antioxidant enzyme catalase in renal tissue. In addition, protein and lipid damage was observed, with no improvement in this condition in the animals 30d after treatment with stem cells. In the evaluated ischemic nephropathy model, treatment with ADSC showed benefits in renal morphology in the short term, but not late, despite the permanence of these cells in the tissue. We believe that oxidative stress, evidenced only in renal tissue with more prolonged ischemia, may have hindered the action of stem cells, contributing to such findings. These results open perspectives for further study on the characterization of ADSC mechanisms of action in anti-fibrogenic responses, as well as the establishment of the number, frequency, routes of administration and the best time to use these cells in the treatment of chronic kidney diseases.

Liquid chromatography-tandem mass spectrometry is effective for analysis of ergosterol in fungal-infected nails.

BACKGROUND: Identification of onychomycosis is mainly based on clinical diagnosis with auxiliary diagnostic methods such as potassium hydroxide (KOH) microscopy, periodic acid-Schiff staining or fungal culture. However, each method is limited by its sensitivity and specificity. AIM: To develop a new test method using the common fungal end product, ergosterol, and investigate if it can be used as a new diagnostic tool. METHODS: We collected consecutive data from 20 participants with nail problems. Following clinical diagnosis, samples were taken for KOH microscopy and for mass spectrometry (MS) to check for the presence of ergosterol. RESULTS: Of the 20 cases collected, 7 were positive for fungal infection by MS. Four of these were already suspected to have onychomycosis, whereas one of the remaining three subjects was presumed to have dry nail and the other two to have onycholysis. The MS test seemed to be better at detecting combinations of nail conditions. Conversely, of the five patients clinically diagnosed as having onychomycosis, four had a positive MS result, whereas the fifth had negative results on both KOH and MS. Two other participants had a positive KOH test and were also found to have positive MS results. CONCLUSION: Detection of the presence of ergosterol by MS seems to be a useful tool for confirming onychomycosis. However, further studies are needed to verify the sensitivity and specificity of this MS method.

Acute Invasive Fungal Rhinosinusitis: Frozen Section Histomorphology and Diagnosis with PAS Stain.

Acute invasive fungal rhinosinusitis (AIFRS) is a fulminant infection in immunocompromised patients requiring rapid diagnosis (DX), frequently made on frozen section (FS) of sinonasal biopsies, followed by prompt surgical debridement. However, FS interpretation is often difficult and DX sometimes not possible. In this study we sought to characterize reasons for misinterpretation and methods to improve diagnostic accuracy. The FS slides from 271 biopsies of suspected AIFRS in a 16-year period were reviewed and the morphologic features evaluated for their utility in DX. Recurring specific patterns of necrosis were identified, which to our knowledge have not been described in the literature. Although they provide strong evidence for AIFRS, identifying fungus consistently in necrotic tissue is essential for DX. Clues to identifying fungus and pitfalls in misidentification were identified, but even with expert knowledge of these, a gap in accurate DX remained. The key to FS DX of AIFRS is to improve fungus identification in necrotic tissues. Methods had been sought in the past to stain fungus at FS without consistent success. The Periodic Acid Schiff's Reaction for Fungi was modified by our histopathology department for use on frozen tissue (PASF-fs) resulting in effective staining of the fungus. It stained fungus on all 62 positive slides when applied retrospectively over hematoxylin and eosin (H&E) stained FSs and used prospectively at FS for DX. Although knowledge of histologic morphology on FS is important, the crucial value of this study is the novel use of PASF-fs to identify fungus in the DX of AIFRS.

Glycogen depletion can increase the specificity of mucin detection in airway tissues.

OBJECTIVE: Mucin is an important parameter for detection and assessment in studies of airway disease including asthma and cystic fibrosis. Histochemical techniques are often used to evaluate mucin in tissues sections. Periodic acid Schiff (PAS) is a common technique to detect neutral mucins in tissue, but this technique also detects other tissue components including cellular glycogen. We tested whether depletion of glycogen, a common cellular constituent, could impact the detection of mucin in the surface epithelium of the trachea. RESULTS: Normal tissues stained by PAS had significantly more staining than serial sections of glycogen-depleted tissue with PAS staining (i.e. dPAS technique) based on both quantitative analysis and semiquantitative scores. Most of the excess stain by the PAS technique was detected in ciliated cells adjacent to goblet cells. We also compared normal tissues using the Alcian blue technique, which does not have reported glycogen staining, with the dPAS technique. These groups had similar amounts of staining consistent with a high degree of mucin specificity. Our results suggest that when using PAS techniques to stain airways, the dPAS approach is preferred as it enhances the specificity for airway mucin.

Periodic acid-Schiff (PAS) reaction and plastination in whole body slices. A novel technique to identify fascial tissue structures.

Since collagen rich fascial tissue is often very delicate and difficult to discern on native tissue slices, we have developed a method for staining full-body slices using the periodic acid-Schiff (PAS) reaction with subsequent plastination. Since the PAS reaction primarily stains carbohydrates, we could exploit the circumstance that different collagen types vary in carbohydrate content. Contrary to fasciae, tissues such as muscle, bone, nerves and blood vessels exhibit significantly less staining or remain unstained. We have validated the whole-body slice staining results in microscopic tissue slides which were stained with standard extracellular matrix stains such as Masson-Goldner trichrome stain and van-Gieson stain. Furthermore, we have performed immunofluorescence imaging to confirm the presence of collagen in the stained tissue. We achieved very good staining and plastination results and were able to clearly identify even very thin fascia in transversal body slices. This technique may prove useful in advancing our knowledge on the complex topography of fascial structures.

Liquid-based cytopathology test as a novel method to identify Aspergillus in patients with pulmonary aspergillosis.

Conventional cytopathology examination of respiratory samples can aid in identifying Aspergillus but with poor sensitivity, so this study aimed to assess the potential of the liquid-based cytopathology test (LCT) for improving the identification of Aspergillus in respiratory samples following Papanicolaou's or Special staining with Grocott's methenamine silver or periodic acid-Schiff staining. Paired bronchial brushing samples (n = 54) and sputum samples (n = 117) from 171 patients with pulmonary aspergillosis were prepared as slides using either conventional cytopathology or SurePath LCT. LCT slides were generally superior to conventional slides, showing smaller cell monolayer surface area, clearer background and more distinct stereoscopic cytological features. For Papanicolaou's staining, LCT-prepared slides allowed a higher positive rate of Aspergillus identification than conventional slides for bronchial brushing samples (59.25% vs. 20.37%, P < 0.05) and sputum samples (29.05% vs. 8.55%, P < 0.05). Similarly, Special staining of LCT-prepared slides showed a higher positive rate of Aspergillus identification for bronchial brushing samples (83.33% vs. 57.41%, P < 0.05) and sputum samples (43.59% vs. 19.66%, P < 0.05). This preliminary study suggests that LCT may be better than conventional slide preparation for identifying Aspergillus in respiratory samples from patients with pulmonary aspergillosis.

Correlation between histopathologic features and likelihood of identifying superficial dermatophytosis with periodic acid Schiff-diastase staining: a cohort study.

BACKGROUND: Periodic acid Schiff-diastase (PAS-D) staining is used routinely in dermatopathology. Conventionally, parakeratosis or intracorneal neutrophils justify use of PAS-D stain to identify dermatophytosis. We aimed to investigate the histopathological features of superficial dermatophytosis. METHODS: Skin biopsies with PAS-D stain were retrospectively reviewed by a blinded dermatopathologist. Histopathologic findings in cases with dermatophytosis were compared with those without. RESULTS: We studied 110 cases, of which 63 were PAS-D positive for dermatophytes. Dermatophytes were identified on hematoxylin and eosin (H&E) staining in 49 (77.8%) of the PAS-D-positive cases. Diffuse compact orthokeratosis (79.37%, p < 0.001) and focal parakeratosis (65.08%, p = 0.03) were significantly more frequent in dermatophytosis. Intracorneal neutrophils and spongiosis were not significant findings. Fungal elements were frequently observed within compact orthokeratosis (62.0%) and parakeratosis (31.8%) but rarely within intracorneal pustules (12.7%). In some dermatophyte cases, intracorneal neutrophils (47.6%) or parakeratosis (17.5%) were absent. CONCLUSIONS: Compact orthokeratosis or focal parakeratosis justifies PAS-D staining, whereas the absence of intracorneal neutrophils or parakeratosis is insufficient to exclude dermatophytosis. Results indicate that having a low threshold to perform PAS-D stain is justified. PAS-D stain may be deferred until H&E slides have been evaluated.

Nail clipping in onychomycosis.

Onychomycosis is the most prevalent onychopathy and it requires a correct early diagnosis. Currently, the diagnostic gold standard is the association of direct mycological test with culture; however, it shows variable sensitivity. The histopathological examination of the distal nail plate, called clipping, has shown to be an adjuvant in diagnosing onychomycosis. This is an easy-to-perform, relatively cheap examination that is little dependent of the examiner, rapidly provides results, has high sensitivity, and for patients it is painless and harmless.

Fluorescence of Candida in diagnosis of oral candidiasis.

BACKGROUND: Many pathogenic fungi fluoresce in hematoxylin and eosin stained sections, and Papanicolaou (PAP)-stained smears under ultraviolet illumination. In theory, this phenomenon could aid in the diagnosis of common fungal infections without the delay which is usually associated with special stains. OBJECTIVE: To evaluate the role of fluorescence as a rapid screening technique for oral infections caused by Candida organisms in exfoliative smears of oral candidiasis. MATERIALS AND METHODS: Two smears and one swab were collected from each of 62 clinically diagnosed cases of oral candidiasis. Smears were stained with (PAP) and periodic acid-Schiff stain (PAS). Both smears were evaluated under light microscopy (LM). Later, PAP smears were observed under fluorescent microscopy (PAP-FM). The swab was inoculated on Sabouraud's agar plate. Each technique was evaluated for sensitivity and specificity. RESULTS: It was found that the PAS-stained smears were more reliable for detection of Candida species than other methods (sensitivity = 100%; specificity = 66.7%). The PAP-LM and PAP-FM showed less sensitivity (67.9% and 85.7%) and specificity (66.7% and 33.3%), respectively. Combined results of both light and fluorescent microscopy of PAP (LM + FM) showed increased sensitivity (89.3%) but reduced specificity (16.7%). CONCLUSION: PAP autofluorescence is less sensitive than PAS, still it accentuates the distinct morphological features of Candida.

Detecting glycogen in peripheral blood mononuclear cells with periodic acid schiff staining.

Periodic acid Schiff (PAS) staining is an immunohistochemical technique used on muscle biopsies and as a diagnostic tool for blood samples. Polysaccharides such as glycogen, glycoproteins, and glycolipids stain bright magenta making it easy to enumerate positive and negative cells within the tissue. In muscle cells PAS staining is used to determine the glycogen content in different types of muscle cells, while in blood cell samples PAS staining has been explored as a diagnostic tool for a variety of conditions. Blood contains a proportion of white blood cells that belong to the immune system. The notion that cells of the immune system possess glycogen and use it as an energy source has not been widely explored. Here, we describe an adapted version of the PAS staining protocol that can be applied on peripheral blood mononuclear immune cells from human venous blood. Small cells with PAS-positive granules and larger cells with diffuse PAS staining were observed. Treatment of samples with amylase abrogates these patterns confirming the specificity of the stain. An alternate technique based on enzymatic digestion confirmed the presence and amount of glycogen in the samples. This protocol is useful for hematologists or immunologists studying polysaccharide content in blood-derived lymphocytes.

Avaliação histopatológica e histoquímica das células claras em lesões odontogênicas císticas / Análisis histopatológico y histoquímico de células claras en lesiones quísticas odontogénicas / Histopathological and histochemical analysis of clear cells in odontogenic cystic lesions

Alterações degenerativas e metaplásicas são usualmente observadas no revestimento epitelial dos cistos odontogênicos. Nos tumores odontogênicos estes processos são considerados mais raros. Objetivo: demonstrar a presença de células claras no revestimento epitelial de uma série de lesões odontogênicas císticas. Métodos: realizou-se um estudo descritivo, em uma amostra de 22 lâminas histológicas, do total de lesões odontogênicas císticas procedentes do Laboratório de Patologia Bucal da Universidade Federal da Paraíba. As lâminas foram examinadas por dois avaliadores previamente calibrados e os blocos parafinados correspondentes às lesões em que se observaram células claras, foram novamente processados, e as lâminas foram coradas pela técnica do Ácido Periódico de Schiff após digestão pela diástase e avaliadas quanto à presença de células mucosas. Resultados: células contendo mucina estavam presentes em 12 (54,5 porcento) das lesões coradas pelo Ácido Periódico de Schiff com diástase. Células mucosas foram observadas em 5 (41,66 porcento) dos 12 casos de cistos radiculares, 1 (50 porcento) dos 2 casos de tumores odontogênicos ceratocísticos, nos 4 (100 porcento) casos de cistos dentígeros e em 2 (100 porcento) casos de ameloblastomas unicísticos. Células claras foram muitas vezes observadas em áreas de inflamação. Conclusão: na amostra estudada, células mucosas puderam ser evidenciadas ocasionalmente no epitélio de lesões odontogênicas císticas(AU)

Cambios metaplásicos y degenerativas se observan generalmente en el revestimiento epitelial de los quistes odontogénicos. En tumores odontogénicos estos procesos son considerados raros. Objetivo: demostrar la presencia de células claras en el epitelio de revestimiento de una serie de lesiones quísticas odontogénicas. Métodos: se realizó un estudio descriptivo, en una muestra de 22 cortes histológicos, del total de lesiones quísticas odontogénicas procedentes del Laboratorio de Patología Oral de la Universidad Federal de La Paraiba. Los cortes fueron examinados por dos examinadores calibrados previamente y los bloques de parafina correspondientes a las lesiones que se observaron con células claras se volvieran a procesar y los cortes fueron teñidos por el Ácido Periódico de Schiff después de la digestión por la diastasa y evaluados para la presencia de células mucosas. Resultados: células contiendo mucina estaban presentes en 12(54,5 por ciento) de las lesiones teñidas por el Ácido Periódico de Schiff con diastasa. Células mucosas fueran observadas en 5(41,66 por ciento) de los 12 casos de quistes radiculares, 1 (50 por ciento) de los 2 casos de tumores odontogénicos queratoquísticos, en los 4 (100 %) casos de quistes dentígeros y en los 2(100 por ciento) casos de ameloblastomas uniquísticos. Células claras fueron muchas veces observadas en zonas de inflamación. Conclusión: En la muestra estudiada, las células mucosas pudieron ser encontradas ocasionalmente en el epitelio de lesiones quísticas odontogénicas(AU)

Metaplastic and degenerative changes are usually observed in the epithelial lining of odontogenic cysts. These processes are considered rare in Odontogenic tumors. Objective: to demonstrate the presence of clear cells in the epithelial lining of a series of odontogenic cystic lesions. Methods: a descriptive study was done, in a sample of 22 histological slides of the total odontogenic cystic lesions originating from the Oral Pathology Laboratory at the Federal University of Paraiba. The slides were examined by two calibrated examiners and the paraffin blocks, corresponding to the lesions, where clear cells were observed, were re-processed and the slides were stained by the Periodic Acid-Schiff technique after digestion by diastase and evaluated for the presence of mucous cells. Results: mucin-containing cells were present in 12 (54,5 percent) of the stained lesions by Periodic Acid-Schiff technique with diastase. Mucous cells were observed in 5 (41.66 percent) of 12 root cysts cases, 1 (50 percent) of 2 keratocystic odontogenic tumors, in 4 (100 percent) cases of dentigerous cysts and in 2 (100 percent) cases of unicystic ameloblastomas. Clear cells were often observed in inflammation areas. Conclusion: In the study sample mucous cells could be evidenced occasionally in the epithelium of cystic odontogenic lesions(AU)

Using unfixed, frozen tissues to study natural mucin distribution.

Mucins are complex and heavily glycosylated O-linked glycoproteins, which contain more than 70% carbohydrate by weight(1-3). Secreted mucins, produced by goblet cells and the gastric mucosa, provide the scaffold for a micrometers-thick mucus layer that lines the epithelia of the gut and respiratory tract(3,4). In addition to mucins, mucus layers also contain antimicrobial peptides, cytokines, and immunoglobulins(5-9). The mucus layer is an important part of host innate immunity, and forms the first line of defense against invading microorganisms(8,10-12). As such, the mucus is subject to numerous interactions with microbes, both pathogens and symbionts, and secreted mucins form an important interface for these interactions. The study of such biological interactions usually involves histological methods for tissue collection and staining. The two most commonly used histological methods for tissue collection and preservation in the clinic and in research laboratories are: formalin fixation followed by paraffin embedding, and tissue freezing, followed by embedding in cryo-protectant media. Paraffin-embedded tissue samples produce sections with optimal qualities for histological visualization including clarity and well-defined morphology. However, during the paraffin embedding process a number of epitopes become altered and in order to study these epitopes, tissue sections have to be further processed with one of many epitope retrieval methods(13). Secreted mucins and lipids are extracted from the tissue during the paraffin-embedding clearing step, which requires prolong incubation with organic solvents (xylene or Citrisolv). Therefore this approach is sub-optimal for studies focusing on the nature and distribution of mucins and mucus in vivo. In contrast, freezing tissues in Optimal Cutting Temperature (OCT) embedding medium avoids dehydration and clearing of the sample, and maintains the sample hydration. This allows for better preservation of the hydrated mucus layer, and thus permits the study of the numerous roles of mucins in epithelial biology. As this method requires minimal processing of the tissue, the tissue is preserved in a more natural state. Therefore frozen tissues sections do not require any additional processing prior to staining and can be readily analyzed using immunohistochemistry methods. We demonstrate the preservation of micrometers-thick secreted mucus layer in frozen colon samples. This layer is drastically reduced when the same tissues are embedded in paraffin. We also demonstrate immunofluorescence staining of glycan epitopes presented on mucins using plant lectins. The advantage of this approach is that it does not require the use of special fixatives and allows utilizing frozen tissues that may already be preserved in the laboratory.

Periodic acid Schiff loops and blood lakes associated with metastasis in cutaneous melanoma.

Aggressive melanoma cells are able to form alternative routes for angiogenesis. The formation of extracellular matrix-rich vasculogenic-like networks [periodic acid Schiff (PAS) loops] and expression of endothelial-associated genes [allowing direct contact of erythrocytes (blood lakes)] are forms of vasculogenic mimicry (VM). The detection of these alternative routes may be used as an additional staging factor for cutaneous melanoma and predicts the route of metastasis in melanoma. We studied the association of the presence of VM with metastasis (lymphogenous and/or haematogenous) in patients diagnosed with cutaneous malignant melanoma in het Groene Hart Hospital, the Netherlands, between 1995 and 2000. Tumour tissue samples of 123 patients were assessed on PAS loops and blood lakes and correlated to clinical data. VM was detected in 42 (34%) and proven metastasis developed in 23 patients (18.7%). VM was associated with shorter survival (P<0.001). In 36 tumours, PAS loops were detected. PAS loops were correlated with the presence of lymphogenous as well as haematogenous metastasis (P=0.062 and 0.013). In 20 tumours, blood lakes were detected and correlated with haematogenous metastasis (P<0.001). In multivariate analyses, the detected blood lakes were significantly associated with haematogenous metastasis (P<0.001, adjusted odds ratio 6.8, 95% confidence interval 1.47-31). Blood lakes were strongly correlated with haematogenous metastasis of cutaneous melanoma and were an independent determinant for survival. These interesting findings need further investigation, although we believe that implementation of this detection can directly lead to better staging of cutaneous melanoma.

[Comparison of different methods for PAS staining of renal biopsy tissue sections].

OBJECTIVE: To compare the performance of a modified PAS staining, traditional PAS staining, Lyon's PAS staining, and Tsunahico Watanabe staining for staining sections of renal biopsy tissue. METHODS: The sections of the renal biopsy tissue were stained with the 4 methods and their staining performance was compared. RESULTS: The modified PAS staining method produced a better contrast and a higher resolution and showed a greater stability after repeated use than the other 3 methods for staining the renal tissue sections (P<0.05). CONCLUSION: The modified PAS staining method shows a better applicability than the other 3 PAS methods for staining sections of renal biopsy tissue.

Endoscopic versus histological diagnosis of Barrett's esophagus: a cross-sectional survey.

CONTEXT: Barrett's esophagus is a common pathological condition in patients with gastro-esophageal reflux disease. OBJECTIVE: The aim of this study was to compare endoscopic diagnosis versus histological confirmation. DESIGN: Cross-sectional. SETTING: Cancer Institute of the Imam Khomeini Hospital. MATERIAL AND METHODS: A total of 50 patients with a history of gastro-esophageal reflux were recruited and underwent upper endoscopy at this cross-sectional survey. Four-quadrant biopsy was taken from all suspected areas of intestinal metaplasia. Sections of blocks were stained with Mixed Alcian Blue (PH 2.5)/PAS and haematoxylin-eosin stainings for the diagnosis of intestinal metaplasia (complete vs. incomplete types) and goblet cell / columnar cell / dysplasia, respectively. MAIN OUTCOME MEASURE: The presence of Helicobacter pylori was assessed by Giemsa staining. RESULTS: There were 44 cases of short-segment Barrett's esophagus and 6 of long-segment Barretts esophagus by endoscopy. When examined by histologic examination, 12 patients with short-segment Barrett's esophagus and 4 with long-segment Barrett's esophagus had intestinal metaplasia. Haematoxylin-eosin staining diagnosed 12 cases of intestinal metaplasia, whereas mixed alcian blue/PAS was used to diagnose 16 cases (κ = 80%, p < 0.001). The positive predictive value in the diagnosis of goblet cell metaplasia and columnar cell metaplasia was 32% and 66%, respectively. Helicobacter pylori infection was observed in 10 cases of those with columnar cell metaplasia without goblet cells, while none of the patients with intestinal metaplasia were infected. CONCLUSION: Our findings suggest that biopsy taking is necessary in all patients with gastro-esophageal reflux disease, whose results suggest columnar cell lining in distal esophagus in endoscopy.