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B Jasani

Publications and source records attributed to B Jasani.

At least 37 records · Page 2Linked to original sources
PubMed2001

Analysis of antigen presenting cell derived exosomes, based on immuno-magnetic isolation and flow cytometry.

We present a simple yet powerful method for the isolation and analysis of exosomes released by antigen-presenting cells (APC). Exosomes are small vesicles (40-90 nm) released by APC, and may have an immuno-regulatory function in vivo. Such exosomes originate from MHC class II peptide loading compartments and, as such, express high levels of MHC Class II. We have utilised magnetic beads, coated with monoclonal antibodies specific for HLA DP, DQ, DR for the specific isolation of exosomes from cell-free supernatants. Beads coated with exosomes are subsequently stained with conjugated antibodies, and analysed by flow cytometry. Characterisation of exosomes by this method demonstrated that exosomes derived from B-lymphocytes express abundant MHC Class I and II molecules. Other immunologically important molecules detected included the co-stimulatory molecules B7.1 (CD80) and B7.2 (CD86). The adhesion molecule ICAM-1 (CD54) was also detected. These exosomes also expressed the B cell marker CD20, and the complement inhibitory protein CD59. The expression of CD63, a lysosomal marker, was variable, and there was no detectable expression of transferrin receptor (CD71). Monocyte derived dendritic cells (cultured for 7 days in GM-CSF/IL-4), demonstrated an immature phenotype, and secreted exosomes with a similar phenotype, with abundant MHC molecules. The expression of CD63 was consistently strong, and the MHC Class I-like molecule CD1a was also present, suggesting a possible function in the presentation of lipid antigens. Again CD59 was expressed suggesting a possible role for APC exosomes in complement regulation. There was no detectable CD71, CD40, CD14, CD20 or CD83. Modification of the extraction protocol allowed a comparative analysis of exosome secretion under various conditions. Treatment of cells with calcium ionophore, or phorbol ester resulted in apparent increases in exosome release, while the phosphatidyl inositol 3-kinase inhibitor, wortmannin, reduced exosome secretion. The immuno-magnetic isolation and analysis of exosomes is a versatile and rapid tool for the analysis of APC exosomes, and may prove a valuable tool for the study of exosome biology.

Androstadienes↗
PubMed2001

Association of SV40 with human tumours.

SV40 was discovered as a contaminant of poliovirus vaccines that were inadvertently administered to millions of people in Europe and the United States between 1955 and 1963. Shortly afterwards, SV40 was proven to be oncogenic in rodents and capable of transforming human and animal cells in vitro. The possibility that SV40 might cause tumours in humans thus became a subject of scientific and public interest and scrutiny. However, largely due to a lack of significant epidemiological evidence, interest in assessing SV40's potential carcinogenic role in humans diminished. Recently, many laboratories have reported the presence of SV40-like DNA in a high proportion of human mesotheliomas, ependymomas and osteosarcoma (the three main types of tumours caused by virus in hamsters), renewing the question whether SV40 might be a human tumour virus. Molecular data from these studies are reviewed to re-evaluate the potential role of SV40 as a human carcinogen.

Animals↗
PubMed2001

Megacystis-microcolon-intestinal hypoperistalsis syndrome and the absence of the alpha3 nicotinic acetylcholine receptor subunit.

BACKGROUND & AIMS: The megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare disease of childhood that presents early with intestinal hypoperistalsis, hydronephrosis, and hydroureters. Transgenic mice that lack the alpha3 subunit containing nicotinic acetylcholine (nAChR) have a phenotype similar to that of MMIHS. METHODS: We examined the expression of this subunit in control and MMIHS tissue derived from patients using in situ hybridization (ISH) and immunocytochemistry (ICC). RESULTS: In controls, both techniques showed a wide distribution of alpha3 nAChRs present in ganglion cells, muscle, and epithelium. By contrast, most MMIHS tissue gave negative staining with ISH and variable results with ICC. CONCLUSIONS: These observations are consistent with a lack of alpha3 nAChRs contributing to the pathogenesis of MMIHS.

Abnormalities, Multiple↗
PubMed2001

p53, p21 and metallothionein immunoreactivities in patients with malignant pleural mesothelioma: correlations with the epidemiological features and prognosis of mesotheliomas with environmental asbestos exposure.

The aim of this study is to investigate immunoreactivity for p53, p21 and metallothionein in diffuse malignant pleural mesothelioma (DMPM) and to determine the relationships between the age, sex, asbestos exposure time, survival of DMPM patients with environmental asbestos exposure and immunoreactivity to p53, p21 and metallothionein. Sixty-seven histopathologically-confirmed DMPMs, 38 of whom had environmental and 29 had occupational asbestos exposure, were included. The tumour tissue samples were immunostained with antibodies against p53, p21 and metallothionein. Epidemiological data and the survival times for the DMPM patients with environmental asbestos exposures were obtained from hospital records. Thirty-three per cent of the DMPMs were positive for p53, 35% for p21 and 52% for metallothionein. There was no statistical difference between the histological subtypes of DMPM in terms of immunoreactivity for p53, p21 and metallothionein. For p21 and metallothionein there was a statistically significant difference between the exposure characteristics: patients with environmental asbestos exposure had shown more immunopositivity. There were statistically significant differences between age groups and between asbestos exposure times for metallothionein, and between asbestos exposure times and p21. The patients with positive immunostaining had longer exposure times and were older than those having negative immunostaining. The differences between survival of the patients were not statistically significant in terms of the immunohistochemical results for p53, p21 and metallothionein.

Age Factors↗
PubMed2001

Thyroid transcription factor-2 gene expression in benign and malignant thyroid lesions.

Thyroid transcription factor-2 (TTF-2) is a recently cloned thyroid-specific gene and is central to the development and differentiation of the thyroid follicular cell. Information regarding transcript levels in normal and diseased adult human thyroids is lacking. We have investigated TTF-2 gene expression in various thyroid pathologies and assessed its potential in preoperative diagnosis of thyroid nodular disease, which is a common clinical problem. We have used reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization (ISH) and detected TTF-2 transcripts in 60% of 125 samples of adult human thyroids tested by RT-PCR (64% of 35) or ISH (59% of 90). In normal thyroid tissues TTF-2 transcript levels are low, 18 of 36 were weakly positive and 18 of 36 negative when tested by ISH. In the benign lesions, TTF-2 transcripts were detected either by RT-PCR or ISH in 8 of 8 Graves disease; 3 of 7 Hashimoto's; 2 of 2 follicular hyperplasia; 15 of 21 follicular adenoma; 11 of 13 multinodular goiters and 0 of 1 hyalinizing trabecular adenoma. In the malignant thyroid lesions, TTF-2 transcripts were detected in 8 of 18 follicular cancers; 0 of 2 anaplastic carcinoma, and 11 of 17 papillary cancers. Compared with normal thyroids, transcripts were more abundant in 24% of thyroid lesions tested by ISH. In conclusion, we report for the first time on TTF-2 gene expression in normal and diseased adult human thyroids.

Adult↗
PubMed2001

Comparison of core oestrogen receptor (ER) assay with excised tumour: intratumoral distribution of ER in breast carcinoma.

AIMS: The use of the H score (involving the assessment of intensity and distribution of positivity) on sections stained for the oestrogen receptor (ER) by immunocytochemistry (ICC) allows different samples to be compared and detailed correlations to be made between hormone receptor expression and morphology. This study assessed the reliability of core biopsy in predicting ER expression in the same tumour excised later at treatment. The distribution of ER within excised tumours was investigated. METHODS: The distribution of ER positivity was investigated in 51 diagnostic core biopsies and across the diameter of 51 subsequently excised tumours in a field by field (magnification, x40; field diameter, 0.4 mm) assessment using the semiquantitive H scoring system. RESULTS: The ER H score in diagnostic core biopsy was significantly higher (p = 0.05, paired rank test; overall mean, 130; n = 51) than the mean in the corresponding excised tumour (mean, 110; n = 51). There was a significant downward trend in ER positivity from the periphery of tumours towards the centre (p = 0.001). The reduction of ER positivity was 6 H score units (2%)/mm. If core biopsies were orientated with the tumour edge at one end no change in ER positivity with field number along the length of the core could be demonstrated. CONCLUSIONS: ER estimation in core biopsies correlated well with expression in tumours but ER expression was higher in the core biopsies than in the excised tumours. ER expression was higher at the periphery of tumours than at the centre. The higher ER expression in cores may reflect the higher chance of sampling the peripheral part of a tumour using a needle core.

Biopsy, Needle↗
PubMed2001

Study of interlaboratory reliability and reproducibility of estrogen and progesterone receptor assays in Europe. Documentation of poor reliability and identification of insufficient microwave antigen retrieval time as a major contributory element of unreliable assays.

Immunohistochemical assays for estrogen receptors (ERs) and progesterone receptors (PRs) have not been surveyed for technical validity. In the present study, the reliability of the immunohistochemical assay for ER and PR was evaluated using data from 105 laboratories participating in external quality assessment (EQA) during a 2-year period. Technical variables associated with reliable immunostaining were analyzed. The efficiency of the antigen retrieval step was identified as the single most important contributory factor influencing the overall reproducibility of the assays. Reliable assays were found in 24 (36%) of 66 laboratories participating in continual EQA, including the majority of centers known to have clinically validated results. Inadequate assay sensitivity, with subsequent weak staining, was the main cause of poor and variable results by laboratories using microwave antigen retrieval; too short a heating time was identified as the principal contributory factor. Extension of the heating time resulted in significant improvement regardless of all other variables in the immunohistochemical protocol. Continual participation in EQA is an effective means for identifying and ameliorating variables that influence the reliability of immunohistochemical assays for predictive markers, thereby assisting in technical validation and standardization.

Antigens↗
PubMed2000

Post-mortem analysis of apoptotic changes associated with human skin bruises.

The estimation of the age of skin bruises is of importance in forensic medicine, especially in child abuse cases. Time-dependent changes in bruise colour and/or associated histological features have been used with a limited degree of success. An increased rate of apoptosis in the injured tissue has been considered as a novel time-dependent marker of cell death, by injury inflicted in a rat model. The object of the present study was to apply the TUNEL method of DNA end labelling to identify and enumerate apoptotic cells in bruised and normal skin in order to study the relationship of apoptotic cell density with the age of the bruise. A commercially available DNA end labelling kit, TUNEL method, was standardised, validated and used for this purpose. Twenty unselected post-mortem cases with bruises due to a variety of causes were studied. The apoptotic cells stained with TUNEL reaction were counted in 10 high power fields in the epidermis, as well as in the dermis of formaldehyde-fixed paraffin-embedded skin specimens. The mean positive cell densities (+/- 1 S.E.) were compared with respect to the age of the bruise. In the epidermis, the mean apoptotic cell count was statistically significantly greater in the bruised skin compared to normal skin in 2- to 6-day-old bruises; whilst in the dermis the same was true in 3- to 8-day-old bruises. The overall findings suggest that there is a quiescent period prior to the increase in the apoptotic cell activity that is seen following skin bruising. This is so provided the post-mortem skin samples were collected within a lapse of 6 days or less between the time of death and formalin fixation and paraffin embedding to avoid the bias made by the difference of length of post-mortem interval.

Adult↗
PubMed2000

Reliability of immunohistochemical demonstration of oestrogen receptors in routine practice: interlaboratory variance in the sensitivity of detection and evaluation of scoring systems.

AIMS: To investigate interlaboratory variance in the immunohistochemical (IHC) detection of oestrogen receptors so as to determine the rate of false negatives, which could adversely influence the decision to give adjuvant tamoxifen treatment. METHODS: To ensure that similar results are obtained by different institutions, 200 laboratories from 26 countries have joined the UK national external quality assessment scheme for immunocytochemistry (NEQAS-ICC). Histological sections from breast cancers having low, medium, and high levels of oestrogen receptor expression were sent to each of the laboratories for immunohistochemical staining. The results obtained were evaluated for the sensitivity of detection, first by estimating threshold values of 1% and 10% of stained tumour cells, and second by the Quick score method, by a panel of four assessors judging individual sections independently on a single blind basis. The results were also evaluated using participants' own threshold values. RESULTS: Over 80% of laboratories were able to demonstrate oestrogen receptor positivity on the medium and high expressing tumours, but only 37% of laboratories scored adequately on the low expressing tumour. Approximately one third of laboratories failed to register any positive staining in this tumour, while one third showed only minimal positivity. CONCLUSIONS: There is considerable interlaboratory variability, especially in relation to the detection of breast cancers with low oestrogen receptor positivity, with a false negative rate of between 30% and 60%. This variability appears to be caused by minor differences in methodology that may be rectified by fine adjustment of overall technique.

Biomarkers, Tumor↗
PubMed2000

Immunohistochemical demonstration of oestrogen and progesterone receptors: correlation of standards achieved on in house tumours with that achieved on external quality assessment material in over 150 laboratories from 26 countries.

AIMS: To investigate the sensitivity of immunohistochemical (IHC) assays for oestrogen receptors (ER) and progesterone receptors (PR) achieved by laboratories on breast tumours fixed and processed in their own department, and to compare this with the degree of sensitivity they achieve on tumours circulated as part of an external quality assessment (EQA) programme. METHODS: On 10 occasions between April 1994 and June 1998, histological sections from breast cancers showing various degrees of expression of ER and PR were circulated for IHC staining to laboratories participating in the UK national external quality assessment scheme for immunocytochemistry (UK NEQAS-ICC). The staining of these tumours, in addition to that of tumours fixed and processed in the participants own laboratories (in house tumours), was assessed by a panel of four assessors, using the established UK NEQAS-ICC scoring system. For a selected assessment run, the degree of expression of participants in house tumours was evaluated by means of the semiquantitative quick score method. RESULTS: Although the scores awarded for the staining of in house tumours were generally higher than those awarded for the staining of UK NEQAS tumours, there was also a significant positive correlation between the two sets of scores. Using the quick score method of evaluation for one of the assessment runs, 47% of in house tumours were classified as having a high degree of ER expression. Of the remaining cases, a significant proportion initially classified as having only low or medium expression of ER were found to have higher expression when stained by the organising laboratory. The UK NEQAS-ICC centre's routine assay for hormonal receptors was found to be 90-100% efficient in achieving optimal demonstration of breast tumours from over 150 different laboratories. CONCLUSIONS: The significant positive correlation between the results obtained on the UK NEQAS tumours and the in house tumours provides evidence for the view that results achieved on EQA material are accurate indicators of in house laboratory performance. Although most laboratories adequately detected tumours with high receptor expression, a large proportion of in house tumours classified initially by participants' staining as being of low or medium ER expression had a higher degree of expression when stained by the UK NEQAS-ICC centre. The efficiency of the organising centre's routine IHC method for ER and PR in optimally demonstrating participants in house breast tumours shows that variations in fixation and tissue preparation are not limiting factors preventing a different laboratory achieving optimal demonstration.

Breast Neoplasms↗
PubMed2000

Frequency of oestrogen and progesterone receptor positivity by immunohistochemical analysis in 7016 breast carcinomas: correlation with patient age, assay sensitivity, threshold value, and mammographic screening.

AIMS: A routine immunohistochemical (IHC) assay is now commonly used for determining the oestrogen receptor (ER) and progesterone receptor (PR) status of women with breast cancer. To date, no large studies have been conducted that report the expected frequency of receptor positivity in relation to patient age and sensitivity of the IHC assay. Data on 7016 breast carcinomas from 71 laboratories were analysed to determine the frequency of receptor positivity and investigate possible causes of the observed variation in detection rates. METHODS: Members of UK NEQAS-ICC (UK National External Quality Assessment Scheme for Immunocytochemistry) provided data on the receptor status of cases routinely assayed in their departments over a period of two to 26 months between June 1996 and September 1998. Data on 7016 breast carcinomas were stratified according to patient age and receptor status. Frequency of receptor positivity was correlated with IHC assay sensitivity, the threshold value used to determine receptor positivity, and the presence or absence of mammographic screening in the hospitals or clinics served by the laboratories. RESULTS: The highest proportion of receptor positive cases occurred in patients in the age ranges > 65 years for ER and 41-50 years for PR. There was a significant positive correlation between frequency of receptor positivity and the sensitivity of the IHC assay, for both ER (rs = 0.346; p = 0.019; two tailed) and PR (rs = 0.561; p = 0.003; two tailed). The mean frequency of receptor positivity for laboratories using the same 10% threshold value was 77% for ER (95% confidence interval (CI), 74% to 80%) in laboratories with high sensitivity and 72% (95% CI, 68% to 76%) for those with low assay sensitivity (p = 0.025). For PR, the mean frequency of receptor positivity for laboratories using the same 10% threshold value and having high assay sensitivity was 63% (95% CI, 57% to 69%), and 51% (95% CI, 38% to 65%) for laboratories with assays of low sensitivity (p = 0.022). The mean frequency of ER positivity for laboratories serving hospitals and clinics where mammographic screening does and does not take place was 73.4% and 75.7%, respectively (p = 0.302; two tailed). CONCLUSIONS: Of the parameters investigated, patient age and IHC assay sensitivity were found to be the main variables influencing the frequency of receptor positivity. We recommend the range of receptor values obtained by laboratories achieving high assay sensitivity as a useful guide against which all laboratories can gauge their own results.

Adult↗
PubMed2000

Metallothionein is expressed in adipocytes of brown fat and is induced by catecholamines and zinc.

Metallothionein (MT) is thought to have an antioxidant function and is strongly expressed during activation of thermogenesis and increased oxidative stress in brown adipose tissue (BAT). Localization and regulation of MT expression in BAT was therefore investigated in rats and mice. Immunohistochemical analysis of BAT from rats exposed to 4 degrees C for 24 h showed that MT and uncoupling protein 1 (UCP1) were coexpressed in differentiated adipocytes, and both cytoplasmic and nuclear localization of MT was observed. Cold induction of MT-1 expression in BAT was also observed in mice. Administration of norepinephrine to rats and isoproterenol to mice stimulated MT and UCP1 expression in BAT, implying a sympathetically mediated pathway for MT induction. In mice, zinc, and particularly dexamethasone, induced MT-2 expression in BAT and liver. Surprisingly, zinc also induced UCP1 in BAT, suggesting that elevated zinc may induce thermogenesis. We conclude that expression of MT in mature brown adipocytes upon beta-adrenoceptor activation is consistent with a role in protecting against physiological oxidative stress or in facilitating the mobilization or utilization of energy reserves.

Adaptation, Physiological↗
PubMed1999

Caveolin and its cellular and subcellular immunolocalisation in lung alveolar epithelium: implications for alveolar epithelial type I cell function.

Caveolae are flask-shaped invaginations of the plasmalemma which pinch off to form discrete vesicles within the cell cytoplasm. Biochemically, caveolae may be distinguished by the presence of a protein, caveolin, that is the principal component of filaments constituting their striated cytoplasmic coat. Squamous alveolar epithelial type I (ATI) cells, comprising approximately 95% of the surface area of lung alveolar epithelium, possess numerous plasmalemmal invaginations and cytoplasmic vesicles ultrastructurally indicative of caveolae. However, an ultrastructural appearance does not universally imply the biochemical presence of caveolin. This immunocytochemical study has utilised a novel application of confocal laser scanning and electron microscopy unequivocally to localise caveolin-1 to ATI cells. Further, cytoplasmic vesicles and flask-shaped membrane invaginations in the ATI cell were morphologically identified whose membranes were decorated with anti-caveolin-1 immunogold label. Coexistent with this, however, in both ATI and capillary endothelial cells could be seen membrane invaginations morphologically characteristic of caveolae, but which lacked associated caveolin immunogold label. This could reflect a true biochemical heterogeneity in populations of morphologically similar plasmalemmal invaginations or an antigen threshold requirement for labelling. The cuboidal alveolar epithelial type II cell (ATII) also displayed specific label for caveolin-1 but with no ultrastructural evidence for the formation of caveolae. The biochemical association of caveolin with ATI cell vesicles has broad implications for the assignment and further study of ATI cell function.

Animals↗
PubMed1999

High metallothionein expression is associated with features predictive of aggressive behaviour in endometrial carcinoma.

AIMS: Metallothioneins (MTs) are a group of ubiquitous low molecular weight proteins with a high affinity for heavy metal ions. The aim of the present study was to investigate MT expression in a series of endometrial carcinomas. We wished to determine whether MT expression in endometrial carcinoma was related to established prognostic factors such as tumour grade, stage and histological type. We also wanted to establish if high MT expression in curettings of endometrial carcinoma was predictive of high expression in the subsequent hysterectomy specimen. METHODS AND RESULTS: Sixty-three cases of endometrial carcinoma were included in the study. These comprised 57 endometrioid adenocarcinomas (15 grade 1, 25 grade 2, 17 grade 3), three papillary serous adenocarcinomas, two mucinous adenocarcinomas and one clear cell adenocarcinoma. Forty-five tumours were stage I, 10 were stage II and eight were stage III. In 28 cases, diagnostic endometrial curettings, performed prior to hysterectomy, were available for study. Immunohistochemical staining was performed using the anti-MT monoclonal antibody E9. The intensity and distribution of MT staining were assessed using a semiquantitative method. This resulted in an intensity distribution (ID) score out of a maximum of 300. The mean ID score of grade 1 and 2 endometrioid adenocarcinomas was 67 and 63, respectively, while for grade 3 tumours the mean ID score was 114. This was statistically significant (P = 0.05). The three papillary serous adenocarcinomas had high ID scores with a mean of 208. The mean ID score of stage I tumours was 69. This was lower than those of stage II and III tumours which had mean ID scores of 116 and 128, respectively. However, these differences were not statistically significant (P = 0.288). A significant correlation was observed between MT ID scores in endometrial curettings and in the subsequent hysterectomy (P = 0.013). CONCLUSIONS: MT isoforms can be demonstrated in most endometrial adenocarcinomas. High MT ID scores are associated with high grade and high stage endometrial adenocarcinomas and with the aggressive papillary serous adenocarcinoma. Whether this is of value as an independent prognostic factor has yet to be established.

Adenocarcinoma↗
PubMed1999

Immunocytochemical detection of metallothionein (MT1 and MT2) in copper-enhanced sheep brains.

The role of metallothionein (MT) in the brain in heavy metal detoxification is relatively unexplored. Brain copper (Cu) elevation although unusual in chronic Cu poisoning in sheep, has been shown to occur after treatment with the chelating agent ammonium tetrathiomolybdate (TTM). The aim of this study was to investigate the expression of MT in TTM Cu-enhanced sheep brains, with immunohistochemical techniques. Brains from TTM-treated, Cu-poisoned sheep were examined for MT immunolabelling with a mouse monoclonal antibody (E9) for MT1 and MT2, and compared with brains from untreated sheep. Brain samples were analysed separately for Cu and zinc (Zn) by atomic absorption spectrophotometry. Markedly increased MT immunoreactivity was found in astrocytes of the cerebellum, thalamus/hypothalamus, cerebrum and medulla oblongata of the high-Cu brains, corresponding to the regional Cu elevations. MT immunolabelling was also found in the pia mater, choroid plexus and ependymal cells. Neurons were rarely labelled. MT induction within astrocytes and at the blood-brain barrier suggests that these are sites of stabilization and possibly transport for Cu and supports the hypothesis that the astrocyte compartment modulates metal homeostasis, conferring protection on vulnerable neurons and effecting damage limitation.

Animals↗
PubMed1999

Natural antibody status in patients with Hashimoto's thyroiditis.

Raised levels of circulating natural antibodies (NABS) have been found in association with systemic lupus erythematosus (SLE) and chronic active hepatitis (CAH), indicative of polyclonal B-cell activation associated with these relatively non-organ specific autoimmune diseases. This study examined the natural antibody response in the organ-specific autoimmune disease Hashimoto's thyroiditis. Serum samples obtained from 69 women with newly diagnosed Hashimoto's thyroiditis together with 64 controls were analysed for IgG and IgM NABS directed at DNA, actin, myoglobin, myosin, trinitrophenyl hapten (TNP) and tubulin as the NAB antigen panel using an established ELISA. The same technique was also used to estimate thyroglobulin and thyroid microsomal autoantibody activities. Compared to a reference panel of normal serum samples, 31 of the Hashimoto's samples showed a greater than 2SD elevation of IgG and/or IgM NABS against one or more of the panel antigens together with elevated IgG thyroglobulin and thyroid microsomal antibody levels. The cases positive for one or more of the NAB panel also showed a greater incidence of active Hashimoto's thyroiditis as indicated by the presence of antibodies directed against the thyroid specific antigens. The above findings suggest that raised levels of NABS are also a feature of this organ-specific autoimmune disease. The wide ranging NAB specificities involved are consistent with an underlying or epiphenomenal state of polyclonal B-cell activation.

Antibodies, Antinuclear↗