Detection of cytomegalovirus in upper gastrointestinal biopsies from heart transplant recipients: comparison of light microscopy, immunocytochemistry, in situ hybridisation, and nested PCR. (57/12862)

AIM: To establish the diagnostic value of in situ hybridisation and the nested polymerase chain reaction (PCR) in detecting clinically relevant cytomegalovirus (CMV) infection in upper gastrointestinal biopsies from heart transplant patients. METHODS: Test sensitivity and specificity for detection of CMV early gene RNA by in situ hybridisation and CMV intermediate early gene by PCR were established and then compared with haematoxylin and eosin (H&E) and immunocytochemical detection of CMV in order to establish the best pathological diagnostic approach. All investigations were carried out on formalin fixed, paraffin embedded tissue. RESULTS: Nested PCR had the highest test sensitivity, followed by in situ hybridisation and immunocytochemistry with the same sensitivity; H&E had the lowest. H&E and immunocytochemistry were the most specific but both had a significant false negative rate which was less of a problem with PCR. However, PCR gave no other diagnostic information, and in situ hybridisation was no better than immunocytochemistry. Both in situ hybridisation and PCR were technically complex and more expensive. CONCLUSIONS: H&E and immunocytochemistry represent the best initial screen for CMV and other diseases in upper gastrointestinal biopsies from heart transplant patients. If H&E and immunocytochemistry were negative, nested PCR could significantly increase the diagnostic yield of clinically relevant CMV infection. In situ hybridisation appeared to have no advantages and some drawbacks compared with immunocytochemistry and PCR.  (+info)

Schwannoma with features mimicking neuroblastoma: report of two cases with immunohistochemical and ultrastructural findings. (58/12862)

OBJECTIVE: A study of two cases of a rare variant of benign schwannoma showing areas mimicking neuroblastoma/peripheral primitive neuroectodermal tumour (PNET). METHODS: Sections of formalin fixed, paraffin embedded specimens were studied by tinctorial stains and immunohistochemistry, and the tissue retrieved from formalin was examined by electronmicroscopy in one case. RESULTS: The tumours were small and subcutaneous. Both showed features of benign schwannoma; one had a multinodular plexiform pattern. In addition, rosette-like structures consisting of collagenous cores surrounded by small round cells or slightly larger epithelioid cells were present. Tumour cells were positive for S100 protein, Leu7, and in one case GFAP, but were negative for neurofilament protein, synaptophysin, and MIC2. Type IV collagen surrounded individual cells. Electronmicroscopy in case 2 confirmed schwannian features (lamina, processes) and failed to show features of neuroblastoma (neuroendocrine granules). CONCLUSIONS: Benign schwannomas may contain rosette-like structures mimicking neuroblastoma/PNET. The techniques used confirmed schwannian differentiation only and eliminated neuroblastoma/PNET. These uncommon variants should be recognised by practising histopathologists to avoid erroneous diagnoses and inappropriate treatment.  (+info)

Immunocytochemical detection of Candida albicans in formalin fixed, paraffin embedded material. (59/12862)

AIM: To assess the ability of the commercially available monoclonal antibody 1B12 (BioGenex, San Ramon, USA) to identify C albicans in formalin fixed, paraffin wax embedded material (FFPE). METHODS: Broth cultures of 20 strains of seven Candida species were resuspended in 4% agarose blocks, fixed in formalin for 24 hours, and embedded in paraffin wax. In addition, 16 blocks of FFPE tissue known to contain periodic acid-Schiff positive fungal hyphae were examined. Antigen retrieval involved microwave treatment of specimens in citrate buffer (0.01 M; pH 6.5) before addition of 1B12 antibody for 24 hours. Bound antibody was subsequently detected using a biotinylated link antibody and a peroxidase conjugated streptavidin. RESULTS: Only C albicans strains were 1B12 positive in the agarose blocks. All FFPE tissue blocks were found to contain 1B12 positive hyphal structures, indicating the presence of C albicans. CONCLUSIONS: The ability to identify candida organisms penetrating the lesional tissue in cases of chronic hyperplastic candidosis will help to clarify the role of individual Candida spp in this important form of oral candidosis.  (+info)

Malignant fibrothecomatous tumour of the ovary: diagnostic value of anti-inhibin immunostaining. (60/12862)

Malignant ovarian tumours of the fibrothecoma group are rare. The clinicopathological features of a case of ovarian malignant fibrothecoma in which there was metastatic disease in the small intestine and peritoneum at presentation are described. A number of differential diagnoses were considered but positive immunohistochemical staining of the resected ovarian and small intestinal neoplasms with anti-inhibin was of value in confirming a sex cord-stromal tumour and in excluding other lesions. The two tumours were also ultrastructurally identical. Classical malignant fibrothecomas are said to show four or more mitotic figures per 10 high power fields (HPF). Although the intestinal secondary was mitotically active, the primary ovarian tumour contained only one to two mitoses per 10 HPF, showing that formal mitotic counts are not an absolute indicator of malignant behaviour in this group of tumours.  (+info)

Ki-67: a useful marker for the evaluation of dysplasia in ulcerative colitis. (61/12862)

AIMS: Evaluation of dysplasia in long standing ulcerative colitis is a difficult and often subjective task. Therefore, the aim of this study was to search for a more objective parameter to help distinguish regenerative changes from epithelial dysplasia. METHODS: A total of 97 sections from colectomy specimens from 12 patients with ulcerative colitis of more than 10 years duration were stained immunohistochemically with MIB 1 to detect differences in the frequency and pattern of nuclei positive for the proliferation marker Ki-67. All patients had epithelial dysplasia in one or more areas (high grade dysplasia, n = 16; low grade dysplasia, n = 15; indefinite for dysplasia, n = 16), and three patients had additional adenocarcinoma (one Dukes's C multifocal, mucinous carcinoma; one Dukes's C adenocarcinoma in the sigmoid; and one Dukes's A adenocarcinoma in the caecum). Two patients had adenomas--one had an 8 cm villous adenoma with intramucosal carcinoma, and the other had a 4 cm tubulovillous adenoma with high grade dysplasia. RESULTS: There were highly significant differences between the percentages of Ki-67 immunopositive cells in low grade and high grade dysplasia and carcinoma compared with regenerative epithelium. In high grade dysplasia and carcinoma, the distribution of Ki-67 positive cells was diffuse throughout the full length of the crypt, whereas low grade dysplasia and epithelium indefinite for dysplasia, as well as regenerative epithelium, showed an expanded basal zone. CONCLUSIONS: Assessment of the number of Ki-67 immunostained cells is of additional value in deciding whether the mucosa is regenerative or dysplastic, and the MIB 1 staining pattern is characteristic for most lesions with high grade dysplasia and carcinoma. Therefore, this technique could be combined with routine histological evaluation of colorectal epithelium being examined for dysplasia.  (+info)

Apoptosis and expression of Bax, Bcl-x, and Bcl-2 apoptotic regulatory proteins in colorectal carcinomas, and association with p53 genotype/phenotype. (62/12862)

AIMS: Spontaneous apoptosis and expression of the apoptotic regulatory proteins Bax, Bcl-x, and Bcl-2 were investigated in 50 colorectal carcinomas. The p53 genotypes/phenotypes and BAX genotypes were also determined, and possible associations of these with apoptosis and/or with expression of the different apoptotic regulatory proteins were studied. METHODS: Terminal deoxynucleotidyl transferase (TdT) mediated dUTP labelling of DNA fragments was used to detect apoptotic tumour cells in sections and peroxidase immunohistochemistry was used to assess protein expression. p53 genotype/phenotype was determined using constant denaturant gel electrophoresis/immunoblotting and bax genotype was determined using polymerase chain reaction based methods. RESULTS: The distribution of tumour apoptotic indices was bimodal with a natural cut off at 1.0% (range, 0.0-5.4%); the median fraction of apoptotic tumour cells was 0.8%. Tumour apoptosis was not associated significantly with tumour DNA ploidy status. Normal mucosal tissue had less than 0.1% apoptotic cells. Staining intensities for Bax, Bcl-x, and Bcl-2 were strong; that is, equivalent to or greater than positive normal mucosal cells, in 11 of 50, 20 of 49, and 20 of 48 carcinomas. Frameshift mutations in the bax gene were detected in three of 42 tumours analysed, all of which were DNA diploid, and Bax protein expression in these tumours was absent or very low. Bax, Bcl-x, and Bcl-2 protein expression were not correlated with tumour apoptosis or tumour DNA ploidy status. p53 was expressed in 34 of 50 tumours and p53 gene mutations were detected in 22 of 29 p53 positive tumours analysed. Apoptosis was significantly lower in a greater number of p53 positive tumours than p53 negative tumours. In addition, Bcl-2 protein expression was significantly higher in a greater number of p53 positive tumours compared with p53 negative tumours. Bax and Bcl-x protein expression were not significantly associated with p53 phenotype/genotype. CONCLUSIONS: The results indicate that acquisition of a p53 phenotype is associated with lower spontaneous apoptosis and higher expression of Bcl-2. The results also suggest that p53 is not a major determinant for Bax expression in colorectal carcinomas in vivo.  (+info)

Detection of Chlamydia trachomatis in vaginal specimens from female commercial sex workers using a new improved enzyme immunoassay. (63/12862)

OBJECTIVE: To evaluate the performance of a new improved enzyme immunoassay (EIA) kit for the detection of Chlamydia trachomatis in vaginal swab and endocervical swab specimens from female commercial sex workers, in comparison with a conventional EIA test and a polymerase chain reaction (PCR) assay. METHODS: A high risk group of 163 female commercial sex workers who visited a sexually transmitted disease (STD) clinic in order to undergo screening for major STDs, including chlamydial infection, were enrolled. A total of four swab specimens, including two vaginal and two endocervical specimens, were collected from each woman by a clinician. To identify C trachomatis, a new improved EIA kit (IDEIA PCE), a conventional EIA kit (IDEIA), and PCR assay (Amplicor) were used. Discrepancies in the results were resolved using supplementary PCR assay. A female patient was considered to be infected with C trachomatis if the IDEIA PCE test and PCR test for both sample sites (endocervical and vaginal) gave positive results. Following resolution of these discrepancies, relative sensitivity and specificity, confidence intervals, and predictive values for each type of specimen by each assay were calculated. RESULTS: Of the 163 women tested, 35 (21.5%) were shown to be infected with C trachomatis. The relative sensitivities in vaginal swab specimens were 88.8%, 68.6%, and 91.4% using IDEIA PCE, IDEIA, and PCR, respectively. The relative specificities in vaginal swab specimens were 99.2%, 99.2%, and 100%, respectively. The relative sensitivities in endocervical swab specimens were 85.7%, 77.1%, and 91.4% with IDEIA PCE, IDEIA, and PCR, respectively. The relative specificities in endocervical swab specimens were all 100%. CONCLUSIONS: The results obtained in this study suggest that the sensitivity and specificity of IDEIA PCE test on vaginal swab and endocervical swab specimens were similar to those of PCR assay on the two types of specimen. It is concluded that IDEIA PCE test on vaginal swab specimens is an acceptable, sensitive, and less invasive approach for the detection of C trachomatis in commercial sex workers with a high prevalence of C trachomatis infection.  (+info)

New enzyme immunoassays for sensitive detection of circulating Candida albicans mannan and antimannan antibodies: useful combined test for diagnosis of systemic candidiasis. (64/12862)

Two standardized enzyme immunoassays for the serological diagnosis of candidiasis were developed. The first one detects antimannan antibodies, while the second one detects mannan with a sensitivity of 0.1 ng/ml. These tests were applied to 162 serum samples retrospectively selected from 43 patients with mycologically and clinically proven candidiasis caused by Candida albicans. Forty-three serum samples were positive for mannan, and 63 had significant antibody levels. Strikingly, only five serum samples were simultaneously positive by both tests. When the results were analyzed per patient, 36 (84%) presented at least one serum positive by one test. For 30 of them, positivity by one test was always associated with negative results by the other test for any of the tested sera. For six patients whose sera were positive for either an antigen or an antibody response, a balance between positivity by each test was evidenced by kinetic analysis of sera drawn during the time course of the infection. Controls consisted of 98 serum samples from healthy individuals, 93 serum samples from patients hospitalized in intensive care units, and 39 serum samples from patients with deep mycoses. The sensitivities and specificities were 40 and 98% and 53 and 94% for mannanemia or antibody detection, respectively. These values reached 80 and 93%, respectively, when the results of both tests were combined. These observations, which clearly demonstrate a disparity between circulation of a given mannan catabolite and antimannan antibody response, suggest that use of both enzyme immunoassays may be useful for the routine diagnosis of candidiasis.  (+info)