Prognostic impact of Ets-1 overexpression in betel and tobacco related oral cancer

In oral squamous cell carcinoma (SCC), the presence of lymph node metastasis is one of the most important prognostic factors, correlating locoregional spread, recurrence, distant metastasis and survival. However, the biological factors implicated and the mechanisms underlying these events are not completely elucidated. We reported Ets-1 expression in oral SCC and proposed that it may serve as a plausible marker of invasive potential and lymph node metastasis. Herein, we investigate the prognostic significance of Ets-1 expression in oral cancer. One hundred oral SCCs assessed for Ets-1 expression showed significant association with tumor stage (P = .027), lymph node involvement (P < 10(-6)) and distant organ metastasis (P = .007). The transcription factor Ets-1 regulates the expression of several genes involved in extracellular matrix remodeling that may account for its association with lymph node and distant organ metastasis. Kaplan-Meier survival analysis entailed significant association of Ets-1 expression in oral SCCs with reduced disease free survival (P = .0041), suggesting its utility as a prognosticator for oral cancer. In conclusion, these findings underscore the role of Ets-1 in oral tumor invasion and metastasis and may thus account for its association with diminished disease free survival.

Alterations in MDM2 expression in esophageal squamous cell carcinoma: relationship with p53 status

In view of the significance of MDM2 as a regulator as well as critical target of wild type p53, this study was undertaken to determine the alteration in MDM2 expression in esophageal squamons cell carcinoma (ESCC) and its relationship to clinicopathological parameters as well as p53gene and protein status. Immunohistochemical analysis of MDM2 and p53 proteins on paraffin embedded sections from 64 surgically resected ESCCs and matched histologically normal tissues showed overexpression of MDM2 protein in 23/64 (36%) ESCCs, while the histopathologically normal esophageal tissues did not show detectable level of MDM2 immunoreactivity. Interestingly, MDM2 /p53 + phenotype was observed in 37/64 (58%) cases. None of the cases with p53 mis-sense mutations (12/30, 40%) showed detectable level of MDM2 protein. Missense p53 mutations were significantly associated with discordant p53 + /MDM2 immunophenotype (p= 0.004). The most intriguing feature of the study was accumulation of MDM2 in the absence of detectable p53 in 11% of and overexpression of MDM2 and p53 in 25% of ESCCs, suggesting a p53-independent role for MDM2 in a subset of tumors. These results underscore the involvement of MDM2 in p53-dependent and -independent pathways in the pathogenesis of esophageal cancer in the Indian population.

Expression of RARalpha and RARbeta in human oral potentially malignant and neoplastic lesions

Retinoids reverse potentially malignant lesions and inhibit the development of second primary cancers in patients with head-and-neck cancer. Many of the effects of retinoids result from modulation of gene expression by 2 distinct classes of nuclear receptor, RARs and RXRs; alterations in their expression can lead to tumorigenesis. To determine whether aberrations in expression of the receptors are related to the development of betel- and tobacco-related oral cancer, we used specific monoclonal antibodies against RARalpha and RARbeta to detect expression of these proteins in 30 histopathologically normal tissues, 45 potentially malignant lesions (leukoplakia) with histological evidence of either hyperplasia (31 cases) or dysplasia (14 cases) and 64 oral squamous-cell carcinomas (SCCs) by immunohistochemistry. Of the 30 normal oral tissues analysed, 8 cases showed detectable levels of RARalpha protein, while 10 cases did not show detectable RARbeta immunoreactivity. Immunostaining for RARalpha protein was observed in 12/31 (39%) hyperplastic lesions, 6/14 (43%) dysplastic lesions and 43/64 (67%) oral SCCs. Expression of RARalpha in oral SCC was significantly associated with the histological differentiation status of tumours (p = 0.016). In contrast, lack of detectable immunoreactivity was observed in 19/31 (61%) hyperplastic lesions, 8/14 (57%) dysplastic lesions and 21/64 (33%) oral SCCs. The hallmark of the study was the significant increase in RARalpha immunopositivity in oral SCCs compared to normal tissue (p = 0.0005) and hyperplastic lesions (p = 0.016). One intriguing feature was the significant decrease in RARbeta immunopositivity in hyperplastic lesions compared with normal oral mucosa (p = 0.05) as well as in oral SCCs compared with normal tissues (p = 0.0008).

Anti-tumor promoting activity of Asteracantha longifolia against experimental hepatocarcinogenesis in rats

Vegetables, natural products of plant origin and numerous non-nutritive dietary constituents have been shown to play a salutary role in cancer chemoprevention. The present study aims to evaluate the chemopreventive efficacy of the methanol fraction of Asteracantha longifolia seed extract against development of 2-acetylaminofluorene (2-AAF)-selected gamma-glutamyl transpeptidase (gamma-GT)-positive foci following diethylnitrosamine (DEN) initiation. Treatment of rats with doses 200 and 400 mg/kg body weight of methanol extract of A. longifolia seeds on alternate days, subsequent to carcinogen treatment, for 6 weeks significantly reduced the incidence and size distribution of gamma-GT-positive foci and tumor formation. Administration of A. longifolia seeds significantly (P<0.001) ameliorated the activities of antioxidant enzymes, glutathione peroxidase (GPx) and catalase (CAT), in a dose-dependent manner. Prophylactic administration of seed extract simultaneous to 2-AAF in the diet, at same doses, significantly suppressed 2-AAF and partial hepatectomy (PH)-induced ornithine decarboxylase (ODC) activity and [(3)H]thymidine incorporation into hepatic DNA, in a dose-dependent manner. Assimilation of the quantitative foci data together with the findings of the modulation of tumor promoting markers give ample evidence to the anti-tumor promoting potential of A. longifolia seeds against chemically-induced hepatocarcinogenesis in Wistar rats.

Frequent alterations in the expression of tumor suppressor genes p16INK4A and pRb in esophageal squamous cell carcinoma in the Indian population

PURPOSE

Alterations in the cell cycle regulatory p16INK4a/Cyclin D1/pRb pathway play a pivotal role in tumorigenesis. Knowledge of alterations in the tumor suppressor protein pRb and its negative regulator, p16CDKN2/MTS1/INK4a in esophageal squamous cell carcinoma (ESCC) from the Indian subcontinent is meager. To gain insight into the mechanisms underlying tumorigenesis and to search for diagnostic molecular markers for ESCC, we analyzed the expression of p16INK4a and pRb in ESCCs in the Indian population.

METHODS

Immunohistochemical analysis of pRb and p16INK4a proteins was carried out in paraffin-embedded sections from 61 surgically resected ESCCs and matched normal tissues, and the results correlated with clinicopathological parameters using chi square and Fisher's exact tests. Dual immunohistochemical analysis has been carried out to demonstrate the concomitant loss of expression of p16INK4a and pRb.

RESULTS

Fifty-nine of 61 (97%) cases showed aberration(s) in either or both of these proteins confirming their critical role in esophageal tumorigenesis. Loss of pRb was observed in 51 of the 61 (84%) and loss of p16INK4a was observed in 35 of 61 (57%) cases. Loss of pRb showed significant association with dedifferentiation of the tumor (P = 0.004). p16-/pRb-, and p16+/pRb- phenotypes were significantly associated with nodal metastasis (P = 0.017 and 0.027, respectively), while p16-/pRb+ phenotype was associated with dedifferentiation of the tumor (P = 0.012).

CONCLUSION

pRb/p16INK4a pathway plays a critical role in esophageal tumorigenesis in the Indian population. The dual hits (concomitant loss) of pRb and p16INK4a expression suggest that these two components are not mutually exclusive, and can both be altered in a significant proportion of primary ESCCs serving as putative diagnostic markers for esophageal cancer. However, the impact of dual hit on tumor behavior and disease prognosis remains to be determined.

Hepatocyte isolation and transplantation in syngenic rats

Refinement of techniques to isolate viable hepatocytes began in the late 1960's. It was established that perfusion of the intact liver as opposed to incubation of liver slices or chopped tissue increased the yield of cells. The present study aims to establish a simple, two-step, collagenase digestion method for hepatocyte isolation. A single inbred Fisher rat was used for hepatocyte isolation. The liver was perfused in-situ with perfusion buffer containing ethylene glycol bis N, N1, tetra acetic acid (EGTA), followed by the collagenase buffer. The liver was excised and gently minced. The tissue was resuspended in the collagenase buffer to complete dissociation. The cell suspension obtained was washed, centrifuged and filtered to complete the isolation procedure. The trypan blue exclusion test showed 80-85% cell viability. The isolated cells were transplanted into the splenic parenchyma of syngenic rats. Survival of the transplanted hepatocytes was confirmed by histological examination at the end of 90 days. This two step technique of in-situ liver perfusion gives a high yield of viable hepatocytes which show long term survival after transplantation.

Effect of intra-tracheal instillation and inhalation of silicon dioxide on some biochemical variables in broncho-alveolar lavage fluid and lung histopathology in rats

In the present study, the bronchial alveolar lavage fluid (BALF) biochemical and lung histopathological changes occurring in response to single large intra-tracheal exposure to silica have been compared to the changes seen after continued chronic exposure via inhalation. Male albino rats (200-250gms) were exposed to silicon dioxide via intratracheal instillation (8mg/0.05ml saline) and whole body inhalation (200mg/m3, 6 hours/day for 2 and 4 weeks) in separate groups . The respective control animals were instilled with normal saline (0.05ml) or exposed to fresh air in simulation chamber for the same duration. BALF was analyzed for total protein, elastase, malondialdehyde (MDA) levels and catalase activity and histopathology of right lung was carried out after 4 weeks post-exposure in intra-tracheal model and after 2 and 4 weeks of exposure in the inhalation model. The levels of total protein, elastase and malondialdehyde (MDA) were significantly elevated, while catalase activity was significantly decreased in the BALF of exposed animals as compared to controls. The histopathological studies of lungs, showed exudates of inflammatory cells, chiefly of macrophages in the alveolar spaces and interstitial septa with multifocal nodular granulomatous lesions. The biochemical findings in BALF of both the models indicate inflammatory changes, lipid peroxidation and fibrosis. However, comparatively lower catalase activity and higher elastase levels in the 4 week inhalationally exposed group than the 4 week post intratracheally exposed group, suggests that these parameters may be affected by acute and chronic exposure and require further confirmation.

Role of lateral neck dissection in cancers of the larynx and hypopharynx with N(o) neck

Radical neck dissection is a standard procedure carried out for the teatment of palpable nodes in the neck but if carried out electively in cases where there are no palpable nodes in the neck it is considered to be an overtreatment with its associated morbity. Lateral neck dissection was carried out on twenty patients who had T31 T4 lesion of the larynx and hypophar-vnx with NO neck. The dissection entails removal of Level II. III and IV nodes. Occult metastasis 80% and 85% respectively. The mean follow up was 13 monts. It appears from our study that elective lateral neck dissection is a promising and safe procedure and may be useful as an important prognostic tool in sampling the lymph nodes and predicting recurrences in the neck.

Association between polymorphism in p21(Waf1/Cip1) cyclin-dependent kinase inhibitor gene and human oral cancer

The cyclin-dependent kinase inhibitor gene p21(Waf1/Cip1) plays a central role in inducing cellular growth arrest, terminal differentiation, and apoptosis. Alterations in this gene may adversely affect regulation of these processes and increase susceptibility for cancer. We have recently reported a novel polymorphism in the p21(Waf1/Cip1) gene in the Indian population and its association with esophageal cancer. An A-->G transition at codon 149 resulted in amino acid substitution from aspartate to glycine in the proliferating cell nuclear antigen binding COOH-terminal domain of p21(Waf1/Cip1) that may affect PCNA-p21(Waf1/Cip1) interactions, thereby affecting regulation of cellular proliferation, and may increase susceptibility for development of cancer. In a parallel study in our laboratory, we searched for putative p21(Waf1/Cip1) mutations in oral premalignant and malignant lesions. No somatic mutation was detected in exon 2 of p21(Waf1/Cip1). Interestingly, a codon 149 polymorphism variant (A-->G) was identified in 11 of 30 (37%) premalignant lesions (7 of 19 hyperplastic lesions and 4 of 11 dysplastic lesions) and 11 of 30 (37%) squamous cell carcinomas (SCCs). This codon 149 variant was also identified in paired lymphocytes of all of the patients with premalignant lesions and SCCs harboring the variant allele, suggesting the occurrence of a polymorphism. Lymphocyte DNA isolated from 50 unrelated age- and gender-matched healthy subjects was screened for this polymorphism. Seven of 50 (14%) normal controls harbored the A-->G codon 149 variant allele. Immunohistochemical analysis of p21(Waf1/Cip1) protein expression showed immunoreactivity in 19 of these 30 (63%) oral premalignant lesions and 16 of 30 (53%) SCCs. The most intriguing features of the study were: (a) the significant increase in frequency of this polymorphism not only in patients with oral SCCs (P = 0.038), but also in patients with premalignant lesions (P = 0.038), compared with normal controls; and (b) the significantly higher frequency of p21(Waf1/Cip1) variants (codon 149) in oral premalignant lesions (10 of 11 cases) and SCCs (11 of 11 cases) with wild-type p53 (P = 0.045) than in lesions with p53 mutations, suggesting that this polymorphism affects the p53 pathway and may play a vital role in oral tumorigenesis. Furthermore, overexpression of p21 protein in oral lesions harboring missense mutations in the p53 gene suggest a p53-independent role for p21 in the pathogenesis of oral cancer.

Circulating p53 antibodies, p53 gene mutational profile and product accumulation in esophageal squamous-cell carcinoma in India

Esophageal cancer (EC) in the Indian population presents in advanced stages with poor prognosis and warrants the identification of a non-invasive marker for early detection and better prognostic assessment. We have previously reported high prevalence of p53 protein accumulation in esophageal squamous-cell carcinomas (ESCCs). The present study was designed to determine (i) if esophageal cancer patients elicit a humoral immune response to intra-tumoral p53 protein accumulation and (ii) their relationship with p53 gene mutations. The goal was to compare the cellular events, p53 protein accumulation and gene mutations with the presence of serum anti-p53 antibodies (p53-Abs) and to assess the utility of serological p53-Ab analysis as a surrogate marker for p53 alterations in esophageal cancer. A high prevalence of circulating p53-Abs was observed in 36 of 60 (60%) ESCC patients. In a subset of 44 ESCCs, exons 5-9 of the p53 gene were examined for mutations by PCR and direct sequencing of PCR products. Mutational data have been correlated with p53-Abs and p53 protein accumulation in ESCCs. Circulating p53-Abs in ESCC patients were significantly associated with intra-tumoral p53 protein accumulation (p=0.0005). A strong correlation observed between humoral immune response against p53 protein, missense gene mutations and protein accumulation warrants the application of serological p53-Abs as a non-invasive surrogate marker in screening high-risk populations for early detection of malignancy.

Circulating p53 antibodies, p53 gene mutational profile and product accumulation in esophageal squamous-cell carcinoma in India

Esophageal cancer (EC) in the Indian population presents in advanced stages with poor prognosis and warrants the identification of a non-invasive marker for early detection and better prognostic assessment. We have previously reported high prevalence of p53 protein accumulation in esophageal squamous-cell carcinomas (ESCCs). The present study was designed to determine (i) if esophageal cancer patients elicit a humoral immune response to intra-tumoral p53 protein accumulation and (ii) their relationship with p53 gene mutations. The goal was to compare the cellular events, p53 protein accumulation and gene mutations with the presence of serum anti-p53 antibodies (p53-Abs) and to assess the utility of serological p53-Ab analysis as a surrogate marker for p53 alterations in esophageal cancer. A high prevalence of circulating p53-Abs was observed in 36 of 60 (60%) ESCC patients. In a subset of 44 ESCCs, exons 5-9 of the p53 gene were examined for mutations by PCR and direct sequencing of PCR products. Mutational data have been correlated with p53-Abs and p53 protein accumulation in ESCCs. Circulating p53-Abs in ESCC patients were significantly associated with intra-tumoral p53 protein accumulation (p=0.0005). A strong correlation observed between humoral immune response against p53 protein, missense gene mutations and protein accumulation warrants the application of serological p53-Abs as a non-invasive surrogate marker in screening high-risk populations for early detection of malignancy.

Circulating p53 antibodies, p53 gene mutational profile and product accumulation in esophageal squamous-cell carcinoma in India

Esophageal cancer (EC) in the Indian population presents in advanced stages with poor prognosis and warrants the identification of a non-invasive marker for early detection and better prognostic assessment. We have previously reported high prevalence of p53 protein accumulation in esophageal squamous-cell carcinomas (ESCCs). The present study was designed to determine (i) if esophageal cancer patients elicit a humoral immune response to intra-tumoral p53 protein accumulation and (ii) their relationship with p53 gene mutations. The goal was to compare the cellular events, p53 protein accumulation and gene mutations with the presence of serum anti-p53 antibodies (p53-Abs) and to assess the utility of serological p53-Ab analysis as a surrogate marker for p53 alterations in esophageal cancer. A high prevalence of circulating p53-Abs was observed in 36 of 60 (60%) ESCC patients. In a subset of 44 ESCCs, exons 5-9 of the p53 gene were examined for mutations by PCR and direct sequencing of PCR products. Mutational data have been correlated with p53-Abs and p53 protein accumulation in ESCCs. Circulating p53-Abs in ESCC patients were significantly associated with intra-tumoral p53 protein accumulation (p=0.0005). A strong correlation observed between humoral immune response against p53 protein, missense gene mutations and protein accumulation warrants the application of serological p53-Abs as a non-invasive surrogate marker in screening high-risk populations for early detection of malignancy.

A histopathological study of esophageal atresia and tracheoesophageal fistula

BACKGROUND/PURPOSE

Histopathologic examination of the esophagus has not been reported often in esophageal atresia (EA) and tracheoesophageal fistula (TEF). Abnormal esophageal motility has been reported after successful repair of EA and TEF, although the exact etiology of this motility disorder remains unclear. Histological evaluation of the fistulous portion of the esophagus has been performed to document any abnormality that may be responsible for the abnormal motility.

METHODS

Histopathological study of fistulous segment of esophageal atresia and distal TEF was conducted on 65 patients, which included autopsy material from 3 patients in whom the entire esophagus was examined by serial section. Special stains were administered to each specimen to look for tracheobronchial remnants and the arrangement of muscle fibers. Clinical evaluation was performed in 27 patients who were available for review 6 months to 9 years after successful surgical treatment. These patients were categorized into 3 groups according to their clinical status.

RESULTS

These findings showed that the majority of these patients have tracheobronchial remnants in the esophagus in the form of abnormal mucous glands and ducts, abnormal mucin secretion, presence of cartilage, and a disorganized muscle coat.

CONCLUSIONS

The presence of abnormal mucous glands and abnormal mucin secretion has not been highlighted before. Although tracheobronchial remnants and a disorganized muscle coat are common findings in the fistulous portion of the esophagus, these may not reflect the structure of the remaining esophagus.

Novel polymorphism in p21(waf1/cip1) cyclin dependent kinase inhibitor gene: association with human esophageal cancer

p21(waf1/cip1), an important regulator of the cell cycle, binds to PCNA and acts as a mediator of the growth suppressing and apoptosis promoting functions of p53. We report a hitherto unobserved polymorphism in the carboxy terminal domain (codon 149) of p21(waf1/cip1) gene, the domain encoding the PCNA binding motif. The codon 149 polymorphism (GAT-->GGT) was observed in 42 of 50 (84%) esophageal squamous cell carcinomas (ESCCs) and eight of 50 (16%) normal individuals. The resultant amino acid substitution from aspartate to glycine may have vital implication in PCNA mediated cell cycle regulation by p21(waf1/cip1). The second polymorphism at codon 31, involving a C-->A transversion at nucleotide 168 (AGC-->AGA) changing the amino acid from serine to arginine, was observed in 2/50 (4%) ESCCs at a relatively lower frequency in the Indian population than that reported in the West. No significant association was observed between p21(wap1/cip1) polymorphism at codon 149 and p21(wap1/cip1) protein expression in ESCC in this cohort of patients. Interestingly, the frequency of p21(wap1/cip1) variants (codon 149) in ESCCs (18 of 19 cases) with wild-type p53 was significantly higher than in tumors with p53 mutations, suggesting that this polymorphism affects the p53 pathway and may play an important role in esophageal tumorigenesis. Analysis of p21(waf1/cip1) expression in relation to p53 gene and protein status revealed its induction by p53-dependent as well as independent pathways in esophageal tumorigenesis.

CD28 interactions with either CD80 or CD86 are sufficient to induce allergic airway inflammation in mice

Previous studies have shown that the pan CD28/cytotoxic T lymphocyte antigen (CTL)A-4 antagonist CTLA4 immunoglobulin (Ig) inhibits eosinophilic airway inflammation in Schistosoma mansoni-sensitized and airway-challenged mice. In the present study, the importance of CD28 as well as the individual roles of CD80 and CD86 were examined in this system using wild-type and CD28 knockout (KO) mice. Unlike wild-type controls, CD28KO mice did not produce systemic IgE or eosinophilic airway inflammation after antigen challenge. However, a lymphocytic infiltrate and continued production of interferon-gamma was observed in these animals. Thus, CD28 is not essential for the initial recruitment of lymphocytes into antigen-challenged airways but critically regulates the allergic T-helper 2 phenotype. We next determined by polymerase chain reaction and flow cytometry that CD80 and CD86 molecules are constitutively expressed in the naive murine lung and on eosinophils in the allergic lung, suggesting a potential important role for both ligands in the development of asthma. Combined anti-CD80/anti-CD86 treatment throughout the antigen challenge period fully blocked the development of allergic airways, whereas a partial reduction was observed in mice treated with either anti-CD80 or anti-CD86 antibody alone. However, only anti-CD86 blocked systemic IgE production. Therefore, signaling through either CD80 or CD86 is sufficient to generate a partial local allergic response, whereas CD86 costimulation is essential to induce systemic allergic (IgE) reactions. Finally, combined anti-B7 monoclonal antibody treatment after sensitization reduced airway eosinophilia and interleukin (IL)-4/IL-5 cytokine secretion consistent with an ongoing role for CD28/B7 interactions in the effector phase of the disease. These results emphasize the importance of differential B7 expression on different cells and in different organs on subsequent CD28/B7-mediated immune events, including the potential for CD28/B7 blockade in the treatment of atopic airway disease in people.

Ets-1: a plausible marker of invasive potential and lymph node metastasis in human oral squamous cell carcinomas

The proto-oncogene Ets-1 is a transcription factor known to regulate the expression of a number of genes involved in extracellular matrix remodelling. It has been postulated to play a role in angiogenesis, cell migration, and regulation of tumour invasion. In betel and tobacco-related oral tumourigenesis, oral squamous cell carcinomas (SCCs) having a poor prognosis often exhibit extensive local disease with spread into regional lymph nodes. At present, no tumour marker is available to predict the metastatic potential of oral carcinomas. To elucidate the involvement of Ets-1 in human oral tumourigenesis, 60 cases of oral SCC, 30 potentially malignant lesions, and 30 samples of normal oral mucosa were examined by immunohistochemistry and the findings corroborated with immunoblotting. The relationship of Ets-1 expression with the degree of differentiation, lymph node metastasis, and tumour stage was determined in oral SCCs. Ets-1 was not detected in the normal oral epithelium. Among the 60 cases of oral SCC, 35 cases (58 per cent) showed positive staining for the Ets-1 protein in tumour cells. In potentially malignant lesions, 14 of 30 cases (47 per cent) showed Ets-1 immunopositivity. Ets-1 expression correlated significantly with tumour stage ( p=0.01) and lymph node metastasis ( p=0.005). The presence of Ets-1 mRNA in oral SCCs was confirmed by reverse transcription-polymerase chain reaction (RT-PCR). These findings suggest that overexpression of Ets-1 in potentially malignant lesions may be related to angiogenesis and its expression in oral SCCs may be one of the factors involved in tumour progression and lymph node metastasis.

Simultaneous alterations of retinoblastoma and p53 protein expression in astrocytic tumors

The genetic alterations frequently involved in glial malignancies are in the tumor suppressor genes, Rb and p53. An altered Rb expression or p53 overexpression is thought to indicate defective tumor suppression and subsequently more aggressive tumors. Therefore, to assess the alterations in the conjoint expression of Rb and p53 proteins in formalin fixed paraffin embedded sections, 64 astrocytic tumors were studied (16 astrocytomas,7 gemistocytic astrocytomas, 19 anaplastic astrocytomas and 22 glioblastomas) using the avidin biotin immunoperoxidase technique. Fifty two cases (81.25%) were found to be positive for p53 protein. Seventeen of these showed aberrant heterogenous staining for pRb, of which 7 were glioblastomas. Only one case of astrocytoma showed aberrant expression of both p53 and Rb. Thus, of the 64 tumors, simultaneous aberrant expression of both p53 and Rb was seen in 21.9% of cases. This was more commonly observed among glioblastoma cases (7/22). No statistical difference was found between the survival rate of heterogenous pRb and p53 positivity in different grades of tumors. In glioblastomas, the survival rate appeared to be less in patients expressing heterogenous pRb, but this was not statistically significant. These results lead us to suspect that p53 and pRb pathways are inactivated, either through mutation or as part of the neoplastic process in astrocytic tumors.

MDM2/p53 co-expression in oral premalignant and malignant lesions: potential prognostic implications

The expression of MDM2 protein in betel and tobacco related oral malignancies in Indian population, its relationship to clinicopathological parameters and p53 protein expression was investigated. Sixty five oral squamous cell carcinomas (SCCs), 33 premalignant lesions (leukoplakia) and 30 normal oral tissues were assessed by immunohistochemical analysis. MDM2 protein was overexpressed in 51/65 (78%) oral SCCs and 17/33 (52%) premalignant lesions; 11/23 hyperplastic lesions and 6/10 dysplastic lesions. mdm2 gene amplification is an infrequent event in oral tumorigenesis. Elevation in the level of MDM2 protein not only in oral SCCs but also in premalignant lesions suggests that altered MDM2 expression is an early even in the pathogenesis of oral neoplasia. The hallmark of the study was the significant association of MDM2 expression with the p53 protein accumulation in 16/33 (49%) oral premalignant lesions (p = 0.001) and 39/65 (60%) malignant lesions (p = 0.021), suggesting an active role for MDM2 in binding and inactivating p53 in oral tumorigenesis. Further, significant association of MDM2/p53 co-expression was observed with advanced tumour stage (p = 0.0009), as well as lymph node metastasis (p = 0.0325) features associated with aggressive tumour behaviour and poor prognosis. Discordant MDM2+/p53-phenotype was observed in 12/65 (18%) oral SCCs suggesting a p53-independent role for MDM2 in the pathogenesis of a subset of oral carcinomas. In conclusion, alterations in MDM2 and p53 expression are early events likely to be involved in preinvasive stages in oral tumorigenesis and may be indicative of a 'gain of function' phenotype with more aggressive characteristics.

P-glycoprotein is positively correlated with p53 in human oral pre-malignant and malignant lesions and is associated with poor prognosis

P-glycoprotein (Pgp) encoded by the MDR1 gene, a predictor of chemoresistance, may also serve as a prognosticator of clinical outcome in cancer patients. The mutant tumour-suppressor p53 protein has been shown to activate the MDR1 promoter, whereas the wild-type p53 represses this activity in cultured cells. We have described the differential expression of Pgp and p53 proteins in betel- and tobacco-related oral tumorigenesis in the Indian population. Herein, Pgp expression was analysed in relation to p53 protein accumulation in pre-malignant and malignant oral lesions by immunohistochemical and flow-cytometric analyses. The relationship between Pgp and p53 protein accumulation and clinicopathological parameters as well as prognosis was determined. Expression of Pgp was observed in 81% of oral squamous cell carcinomas (SCCs) and 71% of pre-malignant lesions. Sixty-five of 75 p53-positive oral SCCs and 21/24 p53-positive pre-malignant lesions showed expression of Pgp. Significant correlation between Pgp and p53 expression was found not only in oral SCCs but also in pre-malignant lesions. Co-expression of Pgp and p53 proteins was indicative of poor prognosis. Follow-up studies of 35 patients showed that 7 of 10 oral SCCs with accumulation of Pgp and p53 proteins also exhibited shorter disease-free survival (recurrence/metastases). Our findings provide clinical evidence for a significant association between Pgp and p53 protein expression in oral tumorigenesis and may account for the aggressive nature of the tumour and poor prognosis.

TRFK-5 reverses established airway eosinophilia but not established hyperresponsiveness in a murine model of chronic asthma

We studied the effects of an anti-interleukin (IL)-5 monoclonal antibody (TRFK-5) or dexamethasone (DEX) to reverse already established airway hyperresponsiveness (AHR) and tissue eosinophilia in a Schistosoma mansoni antigen-sensitized and airway-challenged mouse model of chronic asthma. In this model at 4 d after antigen challenge there is dramatic bronchoalveolar lavage fluid (BAL) eosinophilia, AHR to intravenous methacholine (MCh), and histologic evidence of peribronchial eosinophilic infiltration and mucoid cell hyperplasia. These changes persist for up to 2 wk after antigen challenge. Treatment with DEX from Days 4 through 10 significantly reduced established airway eosinophilia compared with animals sham-treated with saline from Days 4 -10 (120 +/- 29 eosinophils/microl BAL for DEX-treated mice versus 382 +/- 60 eosinophils/microl BAL for sham-treated animals, p < 0.01). DEX-treated mice also had dramatically reduced mucoid cell hyperplasia, and airway responsiveness returned to normal. In contrast, TRFK-5 given during the same time period reduced airway eosinophilia (86 +/- 32 eosinophils/microl BAL versus 382 +/- 60 eosinophils/microl BAL, p < 0.01) but did not reduce goblet cell hyperplasia or reverse already established AHR. Treatment with DEX but not TRFK-5 also inhibited interferon gamma (IFN-gamma) content of BAL fluid (0.49 +/- 0.09 ng/ml BAL fluid for DEX versus 1.50 +/- 0.24 ng/ml BAL fluid and 1.36 +/- 0.13 ng/ml BAL fluid for TRFK-5 and sham-treated mice, respectively, both p < 0.001 versus DEX). Thus, treatment with DEX reduces established eosinophilic airway inflammation and AHR in S. mansoni-sensitized and airway-challenged mice but treatment with TRFK-5 reversed established eosinophilia without ameliorating established AHR. Together, these data suggest that once airway inflammation develops, neutralizing the effects of IL-5 or reducing eosinophilia alone may not result in inhibiting established AHR in atopic asthma.

Precursor lesions of Wilms' tumor in Indian children: a multiinstitutional study

BACKGROUND

Studies regarding different ethnic populations of children with Wilms' tumor (WT) in the U. S. have shown differences between age and gender incidence and the type of its precursor lesions (nephrogenic rests). To the authors' knowledge there are few reports in the literature regarding nephrogenic rests in a large number of cases from other parts of the world.

METHODS

In this study, histopathology sections from 127 WTs were pooled from the archives of 4 institutions in northern India and studied for the incidence of nephrogenic rests. Their incidence also was cross-correlated with patient age gender, and tumor morphology.

RESULTS

Significantly, the complete absence of perilobar nephrogenic rests was observed in all cases. Intralobar rests were associated with 45.3% of WTs and were observed predominantly with a triphasic histologic pattern and a relatively lower incidence of anaplasia compared with reports in the Western literature (1.5% vs. 4.5%). A lower median age of 2.5 years with a peak in the first 2 years of life was consistent with reported studies in Asian children. The male gender preponderance was in contrast to the equal male to female ratio reported in Western cases.

CONCLUSIONS

The type of nephrogenic rests present in Indian children was noted to be different from that in children reported in the Western literature. Differences also existed with regard to the age and gender incidence of children with WT and its morphologic pattern, possibly due to the different genetic nature of the tumor. However, this theory requires confirmation by large epidemiologic and genetic studies.

Circulating p53 antibodies as early markers of oral cancer: correlation with p53 alterations

p53 aberrations are early events in the pathogenesis of betel- and tobacco-related oral malignancies. Accumulation of p53 protein in oral lesions may elicit a humoral immune response against p53 protein in these patients. p53 antibodies (Abs) were analyzed in 183 sera obtained from patients with premalignant or malignant oral lesions and normal individuals by enzyme-linked immunoassay using recombinant p53 protein as antigen. These results were correlated with accumulation of p53 protein in patients' matched oral tissue specimens. Circulating p53 Abs were observed in 24 of 70 (34%) cancer patients and 15 of 50 (30%) patients with premalignant oral lesions. p53 Abs showed a significant association with increase in tumor size and dedifferentiation of tumors, factors indicative of poor prognosis. Expression of p53 protein was analyzed in 43 matched oral lesions (18 premalignant and 25 malignant cases). All the p53-seropositive patients (7 leukoplakia and 11 squamous cell carcinoma) showed elevated levels of p53 protein in matched oral lesions. However, the total number of patients seropositive for p53 Abs was lesser than that of patients exhibiting p53 protein accumulation in oral lesions. Four of the 63 normal healthy individuals who were heavy consumers of tobacco (smoking/chewing) and betel were found to be positive for p53 Abs. Detection of circulating p53 Abs in patients with premalignant oral lesions suggests that humoral immune response against p53 protein is an early event in oral oncogenesis and may be a surrogate marker for both p53 alteration and preclinical cancer.

Expression of cyclin dependent kinase inhibitor p21waf1/cip1 in premalignant and malignant oral lesions: relationship with p53 status

p21waf1/cip1 protein, an inhibitor of cyclin dependent kinases, is a critical downstream target in the p53-specific pathway of growth control, and can also be induced by p53 independent pathways in relation to terminal differentiation. p21waf1 is also a putative tumour suppressor. Hence, we sought to determine whether this protein is abnormally expressed during betel- and tobacco-related oral oncogenesis. The aim was to determine whether a correlation exists between the expression profile of p21 and clinicopathological parameters of the patients, as well as with their p53 status. Immunohistochemical analysis showed that the expression of p21 protein in premalignant lesions was consistently elevated in the superficial, differentiated cells of the epithelium, while overexpression of the p53 tumour suppressor gene was observed in the basal proliferating layers of the epithelium. Our study demonstrated that p21 overexpression is associated with differentiation in proliferating dysplasias and squamous cell carcinomas (SCCs). The expression of p21 and p53 proteins was observed in 11/25 premalignant lesions. In 7 of these 11 cases, a heterogenous pattern of expression of p21 and p53 was observed. Four of these 11 premalignant and 30/51 malignant lesions showed concordant expression of both p21 and p53 proteins. The discordant p21 +/p53- phenotype was observed in 4/25 premalignant lesions and 5/51 oral SCCs. The p21-/p53+ phenotype was observed in 5/25 premalignant lesions and 7/51 oral SCCs. These results suggest that induction of p21 occurs by both p53 dependent and independent mechanisms during oral tumorigenesis.

pRb and p16 protein alterations in human oral tumorigenesis

Cyclin dependent kinase inhibitor 2/multiple tumour suppressor gene 1 (CDKN2/MTS1) and retinoblastoma (Rb) tumour suppressor genes play important roles in the regulation of the cell cycle. The protein products of these genes p16INK4 (p16) and pRb, respectively, like p53 protein inhibit progression from G1 to S phase. p16 exerts its function through inhibition of CDK4-mediated phosphorylation of pRb. The pRb/p16 pathway is a critical target for molecular aberration at the G1-S checkpoint in a wide range of primary human tumours. The expression of p16 and pRb proteins was analyzed by immunohistochemistry in 35 cases of oral squamous cell carcinomas (SCCs), 22 cases of premalignant oral lesions and 30 normal oral tissues. Lack of pRb expression was observed in 23/35 (66%) oral SCCs and 14/22 (64%) premalignant lesions. Lack of p16 expression was observed in 22/35 (63%) oral SCCs and 13/22 (59%) premalignant lesions. Weak p16 and pRb immunoreactivities were observed in normal oral mucosal epithelium. The status of p16 and pRb was correlated with clinicopathological characteristics of the patients. Alteration in p16 expression showed significant correlation with tumour staging and progression (P = 0.024). Alteration in pRb/p16 expression correlated with heavy consumption of betel and tobacco. Our results suggest that alterations in the p16/pRb pathway are early events in oral tumorigenesis and may be involved in the development of betel- and tobacco-related oral malignancies.

Assessment of proliferative potential of meningiomas using PCNA LI and AgNOR counts

Seventy-six cases of international meningiomas were studied using staining for Proliferating Cell Nuclear Antigen (PCNA) and silver nucleolar organizer regions (AgNORs) in order to find out any correlation of these parameters to the histological typing of the tumours and their biological behaviour. Histologically, 35 of the 76 cases were benign, 12 atypical and 19 malignant. Ten cases were recurrent. A male preponderance with a male: female ratio of 1.6:1 was noted. Five of 76 cases were in children below 15 years of age. Majority of the tumours were convexity meningiomas. Overall PCNA labeling index (LI) values ranged from 0.1% to 11.0%. Benign group had an LI of 0.9 +/- 1.42 whereas atypical, malignant and recurrent group had LIs of 4.06 +/- 2.33, 2.91 +/- 2.66 and 3.36 +/- 3.76 respectively. One way analysis of variance test showed a significant difference in the distribution of LI between benign versus atypical, malignant and recurrent group (P < 0.05). A highly significant difference was also observed between PCNA LI of recurrent benign group versus non-recurrent benign group (p < 0.01, wilcoxon Rank Sum Test). On further classifying the tumours based on LI values, it was observed that 30 of 41 (73%) cases of combined atypical, malignant and recurrent group (i.e. biologically more aggressive group) had LI of > 1%, whereas 26 of 35 cases (74%) belonging to the benign group had LI of < 1%. Overall AgNOR counts ranged from 1.27 to 3.11. No statistically significant difference was found in AgNOR counts amongst the different groups of meningiomas. There was no correlation between PCNA LI and AgNOR counts. It was thus concluded that PCNA LI but not AgNOR counts in the primary tumour could be of potential value for more accurate assessment of biologic behaviour of meningiomas in conjunction with the conventional A histological parameters.

CTLA4Ig inhibits airway eosinophilia and hyperresponsiveness by regulating the development of Th1/Th2 subsets in a murine model of asthma

Complete T-cell activation requires two distinct signals, one delivered via the T-cell receptor, and the second "co-stimulatory" signal through CD28/B7 ligation. Previous studies showed that the blockade of CD28/B7 ligation alters differentiation of Th1/Th2 lymphocyte subsets in vitro and in vivo. The present study was designed to determine the effect of a CD28/B7 antagonist (CTLA4Ig) on Th1/Th2 development in Schistosoma mansoni-sensitized and airway-challenged mice. Treatment of mice with CTLA4Ig beginning 1 wk after sensitization abolished airway responsiveness to intravenous methacholine determined 96 h following antigen challenge. We also found a significant reduction in bronchoalveolar lavage (BAL) eosinophilia, and reduced peribronchial eosinophilic infiltration and mucoid-cell hyperplasia. Furthermore, CTLA4Ig treatment significantly decreased interleukin (IL)-4 and IL-5 content in BAL fluid in vivo, and the production of IL-5 by lung lymphocytes stimulated with soluble egg antigen (SEA) in vitro. In contrast, the content of interferon-gamma in BAL fluid and supernatant from SEA-stimulated lung lymphocytes from CTLA4Ig-treated mice was increased significantly compared with untreated animals. Thus, CTLA4Ig inhibits eosinophilic airway inflammation and airway hyperresponsiveness in S. mansoni-sensitized and airway-challenged mice, most likely due to attenuated secretion of Th2-type cytokines and increased secretion of Th1-type cytokines.

RNA polymerase of vesicular stomatitis virus specifically associates with translation elongation factor-1 alphabetagamma for its activity

An RNA-dependent RNA polymerase is packaged within the virions of purified vesicular stomatitis virus, a nonsegmented negative-strand RNA virus, which carries out transcription of the genome RNA into mRNAs both in vitro and in vivo. The RNA polymerase is composed of two virally encoded polypeptides: a large protein L (240 kDa) and a phosphoprotein P (29 kDa). Recently, we obtained biologically active L protein from insect cells following infection by a recombinant baculovirus expressing L gene. During purification of the L protein from Sf21 cells, we obtained in addition to an active L fraction an inactive fraction that required uninfected insect cell extract to restore its activity. The cellular factors have now been purified, characterized, and shown to be beta and gamma subunits of the protein synthesis elongation factor EF-1. We also demonstrate that the alpha subunit of EF-1 remains tightly bound to the L protein in the inactive fraction and betagamma subunits associate with the L(alpha) complex. Further purification of L(alpha) from the inactive fraction revealed that the complex is partially active and is significantly stimulated by the addition of betagamma subunits purified from Sf21 cells. A putative inhibitor(s) appears to co-elute in the inactive fraction that blocked the L(alpha) activity. The purified virions also package all three subunits of EF-1. These findings have a striking similarity with Qbeta RNA phage, which also associates with the bacterial homologue of EF-1 for its replicase function, implicating a possible evolutionary relationship between these host proteins and the RNA-dependent RNA polymerase of RNA viruses.

TLS (translocated-in-liposarcoma) is a high-affinity interactor for steroid, thyroid hormone, and retinoid receptors

Nuclear receptors for steroid hormones, thyroid hormone, retinoids, and vitamin D are thought to mediate their transcriptional effects in concert with coregulator proteins that modulate receptor interactions with components of the basal transcription complex. In an effort to identify potential coregulators, receptor fusions with glutathione-S-transferase were used to isolate proteins in nuclear extracts capable of binding nuclear hormone receptors. Glutathione-S-transferase fusions with mouse retinoid X receptor-alpha enabled the selective isolation of a 65-kDa protein (p65) from nuclear extracts of rat and human cells. Binding of p65 to mouse retinoid X receptor-alpha was centered around the DNA-binding domain. p65 also bound regions encompassing the DNA-binding domain in estrogen, thyroid hormone, and glucocorticoid receptors. p65 was identified as TLS (translocated-in-liposarcoma), a recently identified member of the RNP family of nuclear RNA-binding proteins whose members are thought to function in RNA processing. The N-terminal half of TLS bound to thyroid hormone receptor with high affinity while the receptor was bound to appropriate DNA target sites. Functional studies indicated that the N-terminal half of TLS can interact with thyroid hormone receptor in vivo. TLS was originally discovered as part of a fusion protein arising from a chromosomal translocation causing human myxoid liposarcomas. TLS contains a potent transactivation domain whose translocation-induced fusion with a DNA-binding protein (CHOP) yields a powerful transforming oncogene and transcription factor. The transactivation and RNA-binding properties of TLS and the nature of its interaction with nuclear receptors suggest a novel role in nuclear receptor function.

Portal hypertensive gastropathy in noncirrhotic patients. The effect of lienorenal shunts

We studied 25 consecutive patients with noncirrhotic portal hypertension to determine whether portal hypertensive gastropathy occurred and whether it was related to hypoacidity, hypergastrinemia, or portal venous congestion. Preoperative tests included gastrointestinal endoscopy, gastric mucosal biopsies, gastric acid estimation, and serum gastrin measurements. All patients had a central splenorenal shunt performed during which a full-thickness gastric biopsy was performed. The tests were repeated 3 to 16 months postoperatively. Eight of the 25 patients showed endoscopic evidence of portal hypertensive gastropathy. The shunt procedure reversed the gastropathy in 6 of 7 patients followed up. Mucosal biopsies revealed vascular ectasia in 24 of 25 patients; in 8 of the most severely affected there was partial or complete regression after surgery. The basal and peak acid outputs in the patients were normal for our laboratory at 2.9 +/- 0.25 meq/hour and 16.37 +/- 0.96 meq/hour, respectively. They remained unchanged after surgery. Fasting serum gastrin levels were also normal both before and after surgery. Our findings indicate that venous congestion is the cause of portal hypertensive gastropathy in patients with noncirrhotic portal hypertension and that it can be reversed by a decompressive procedure.

Heat shock protein (HSP) expression and proliferation of tubular cells in end stage renal disease with and without haemodialysis

BACKGROUND

Prolonged dialysis is associated with acquired cystic kidney disease (ACKD) and also higher incidence of renal cell carcinoma. Relationship among dialysis, tubular cell proliferation, development of cystic change and neoplastic transformation is not clearly known. Whether dialysis causes additional stress on tubular cells is also conjectural. Study of heat shock protein (HSP) expression which are rapidly synthesized in cells in response to a variety of stresses may be helpful in this regard.

METHODS

To evaluate dialysis induced early changes in end stage renal disease (ESRD), kidneys from eight adult autopsied patients were examined (group I) who were on weekly maintenance haemodialysis for 3-12 months. The heat shock protein (HSP 72/73) expression of tubular epithelial cells and their proliferating cell nuclear antigen (PCNA) labelling index (LI) were studied by immunohistochemistry using monoclonal antibodies. For comparison similar study was carried out in 10 cases of ESRD (Group II) of similar age and sex distribution who were not dialysed. The atrophic tubules were subtyped morphologically into (1) classic, (2) thyroid, (3) endocrine and (4) super tubules.

RESULTS

In the dialysed group (I) the percentage of hyperplastic super tubules (10.6 +/- 4.1%) was significantly higher than in the non-dialysed group (II) (5.2 +/- 1.3%) with a higher PCNA LI (6.8 +/- 2.04%) (group II 4.9 +/- 1.9%) (P < 0.01 to < 0.001). Though grossly not detected, but microscopic cysts and microadenoma like areas were seen in all the cases in group I with a mean diameter of 522.66 +/- 315.25 microns and 494.85 +/- 262.46 microns respectively. They were seen in one case of group II. PCNA LI of the cells in microadenoma (7.2 +/- 3.1%) and microcysts (6.6 +/- 2.6%) were similar to that of super tubules in group I. Quantitation of HSP expression by image analysis (optical density 2.309 +/- 0.155) showed a positive correlation (r = 0.7555) (P < 0.001) with PCNA LI in super tubules indicating a higher induction in the dialysed group.

CONCLUSIONS

This study suggests that haemodialysis may cause injury to tubular cells and aggravate stress on an already compromised situation of ESRD leading to increased cell proliferation and more hyperplastic supertubule formation which may be the forerunner of cyst formation as well as neoplastic transformation.

High prevalence of p53 gene alterations and protein overexpression in human esophageal cancer: correlation with dietary risk factors in India

Epidemiological studies have demonstrated an association between human esophageal cancer and dietary/nutritional risk factors in developing countries. We examined the expression of p53 protein in 51 cases of esophageal squamous cell carcinomas (ESCCs) and paired normal esophageal tissues by immunohistochemistry. Alterations in the tumor suppressor gene p53 (exons 5-8) were analyzed in 51 cases of ESCC and paired normal tissues by PCR and single-strand conformation polymorphism. p53 protein expression was correlated with major dietary risk factors and common carcinogens identified in India. Immunohistochemical analysis of frozen esophageal tissue sections using anti-p53 monoclonal antibody (D0-1) showed overexpression of the protein in the nuclei of epithelial cells in 39 of 51 (76%) cases. The histopathologically proven normal esophageal tissue sections taken from a distant site from esophageal cancer patients did not show any detectable level of p53 immunoreactivity. The PCR-single-strand conformation polymorphism analysis showed a mobility shift in 37 of 51 (72%) ESCCs. Intake of chilies was positively associated with p53 protein expression (P < 0. 01) in the esophageal cancerous lesions. Our results suggest that p53 alterations are frequent events in esophageal oncogenesis in the Indian population, which has dietary habits that are considerably different from those of the Western population.

Phosphorylation within the amino-terminal acidic domain I of the phosphoprotein of vesicular stomatitis virus is required for transcription but not for replication

Phosphorylation by casein kinase II at three specific residues (S-60, T-62, and S-64) within the acidic domain I of the P protein of Indiana serotype vesicular stomatitis virus has been shown to be critical for in vitro transcription activity of the viral RNA polymerase (P-L) complex. To examine the role of phosphorylation of P protein in transcription as well as replication in vivo, we used a panel of mutant P proteins in which the phosphate acceptor sites in domain I were substituted with alanines or other amino acids. Analyses of the alanine-substituted mutant P proteins for the ability to support defective interfering RNA replication in vivo suggest that phosphorylation of these residues does not play a significant role in the replicative function of the P protein since these mutant P proteins supported replication at levels > or = 70% of the wild-type P-protein level. However, the transcription function of most of the mutant proteins in vivo was severely impaired (2 to 10% of the wild-type P-protein level). The level of transcription supported by the mutant P protein (P(60/62/64)) in which all phosphate acceptor sites have been mutated to alanines was at best 2 to 3% of that of the wild-type P protein. Increasing the amount of P(60/62/64) expression in transfected cells did not rescue significant levels of transcription. Substitution with other amino acids at these sites had various effects on replication and transcription. While substitution with threonine residues (P(TTT)) had no apparent effect on transcription (113% of the wild-type level) or replication (81% of the wild-type level), substitution with phenylalanine (P(FFF)) rendered the protein much less active in transcription (< 5%). Substitution with arginine residues led to significantly reduced activity in replication (6%), whereas glutamic acid substituted P protein (P(EEE)) supported replication (42%) and transcription (86%) well. In addition, the mutant P proteins that were defective in replication (P(RRR)) or transcription (P(60/62/64)) did not behave as transdominant repressors of replication or transcription when coexpressed with wild-type P protein. From these results, we conclude that phosphorylation of domain I residues plays a major role in in vivo transcription activity of the P protein, whereas in vivo replicative function of the protein does not require phosphorylation. These findings support the contention that different phosphorylated states of the P protein regulate the transcriptase and replicase functions of the polymerase protein, L.

Loss of heterozygosity of a locus on 17p13.3, independent of p53, is associated with higher grades of astrocytic tumours

Amongst the human astrocytic tumours, the commonest of primary brain tumours, the clinical outcome of astrocytoma (AS) is significantly better than anaplastic astrocytoma (AA) and glioblastoma multiforme (GBM). Often, low grade tumours can progress to or recur with a more malignant phenotype. Recent loss of heterozygosity (LOH) reports suspect the involvement of a tumour suppressor gene, different from p53, in the 17p13.3 region of the human chromosome. However, the effect of LOH of 17p13.3 region on tumour histology at presentation and prognosis is as yet undefined. As a first step to define the role of this putative oncogene in astrocytic tumour progression, we correlated the LOH of a locus, D17S379, in 17p13.3 region and the p53 locus in 17p13.1 region with the histopathology of astrocytic tumours by PCR based microsatellite and restriction fragment length polymorphism of DNA extracted from microdissected paraffin sections of 45 astrocytic tumours of different histopathological grades. LOH of D17S379 was significantly associated (P=0.02) with AA and GBM (high grade malignancy), while no such preferential association was found with LOH of p53. There were no mutations in the exons 5 to 9 of p53 gene in the five tumours with LOH of D17S379 but not of p53 region. In a case of AA with a heterogenous microscopic appearance, heterozygosity of D17S379 was lost only in the area with a more malignant histology while both areas had no LOH or mutation of p53. A locus at the 17p13.3 region, independent of the p53 locus, is involved in a large subset of astrocytic tumours during transformation into a more malignant phenotype, and thus may be a link in the chain of genetic events occurring in astrocytic tumour progression.

Changing patterns of Vibrio cholerae isolation over three consecutive cholera seasons (1992-1994) in east Delhi

The emergence of new strains of Vibrio Cholerae has added a new dimension to the variability in pathogenicity and potential virulence of the organisms precipitating diarrhoeal diseases. Considering the shifting patterns of V. cholerae 01 there is a continuous need to monitor the strain characteristics. In this study total 541 stool specimens of acute secretory diarrhoea were investigated between May 1992 and November 1994 for strains of Vibrio Cholerae and anti-microbial susceptibility testing of all the confirmed V. Cholerae strains. In 1992, 50 of the 125 strains (40%) were positive for V. cholerae 01 predominantly biotype El Tor serotype ogawa, and 10 (80%) of non 01 type, with most strains susceptible to tetracycline (100%), chloramphenicol (98%) and Cotrimoxazole (98%), but all resistant to polymyxin B and furazolidine. In 1993, 44 (43.6%) of the 010 strains were positive for V. cholerae 0139 and the rest V. cholerae 01. In 1994, another sero group of V. cholerae 010 emerged, with 42 (13.3%) being positive. Isolates did not agglutinate with any of these antisera and have been labelled as 'other than non-01 vibrio cholerae'.

Role of extramucosal seromuscular biopsy during preliminary fecal diversion in the management of Hirschsprung's disease

The routine use of frozen section biopsy to identify distal ganglionic bowel in Hirschsprung's disease is the accepted norm in well developed centers. With the aim of overcoming non-availability of frozen section biopsy and reducing the duration of definitive surgery, an alternative algorithm, based on extramucosal seromuscular biopsy at the time of preliminary fecal diversion and its examination by routine paraffin sections and staining, was developed and used in 100 patients at our centre. This technique accurately marked the ganglionic colon for pull-through operation in 96.2% of cases with rectosigmoid transition zone and in 91.7% of those with transition zone in the descending colon, thus obviating the need for frozen section biopsy and saving nearly one hour during the pull-through surgery. However, in the more proximal varieties of Hirschsprung's disease frozen section biopsy was still considered to be indispensable.

Recurrent pyogenic cholangitis or "oriental cholangiohepatitis' in occidentals: case reports of four patients

The first description of recurrent pyogenic cholangitis occurring in four occidentals is presented. While recurrent pyogenic cholangitis is a common syndrome of uncertain aetiology among orientals (also known as oriental cholangiohepatitis), it has not previously been described in occidentals. Four such patients are described. They presented with recurrent attacks of ascending cholangitis and associated hepatolithiasis, biliary stricturing and dilation. Focal hepatic involvement was treated by segmental liver resection and recurrent disease by interventional endoscopy or radiology.

The nature and significance of liver cell vacuolation following hepatocellular injury--an analysis based on observations on rats rendered tolerant to hepatotoxic damage

Swelling with nonlipid cytoplasmic vacuolation of diffusely distributed hepatocytes is seen consistently after mild acute and subacute liver injury. Several lines of evidence point to the possibility that this change may reflect a cellular adaptation beneficial to the host, rather than a degenerative change. The nature and significance of this morphological manifestation were tested in batches of albino rats given small doses of a variety of hepatotoxins, some of which were subsequently challenged with a large highly necrogenic dose of carbon tetrachloride (CCl4). Morphological and biochemical investigations showed that cytoplasmic vacuolation of liver cells following low doses of toxins was due to excess accumulation of glycogen, predominantly of the monoparticulate form. These cells lacked features of degeneration or regeneration and were much less susceptible to injury by the large dose CCl4, as assessed by structural and serum enzyme analyses. This tolerance to toxic damage seemed to be associated with excess accumulation of intracellular glycogen. We conclude from these and other observations on animal and human livers that many of the vacuolated hepatocytes seen in liver injury are cells adaptively altered to resist further insult rather than cells undergoing hydropic degeneration, as is commonly believed.

Characterisation of Vibrio cholerae 0139 isolated from diarrhoeal stools

A total of 174 samples of acute diarrhoeal stools received over a period of seven months, yielded 101 isolated morphologically and biochemically resembling Vibro cholerae. Serologically, 57(56.4 per cent) of the 101 isolates were identified as V. cholerae 01 and remaining 44 (43.6 per cent) as V. cholerae 0139. Keeping in mind the unique potential of 0139 among non 01 vibrio to cause epidemics, we decided to undertake the study of biochemical characters and physiological behaviour of all the 44 V. cholerae 0139 isolates. All the stains were Voges Proskauer's test positive' haemagglutinating and grew in the presence of 6 per cent sodium chloride. 13 (29.5 per cent) strains showed haemolytic activity. Nine (20.5 per cent) were polymyxin-B sensitive and 4 (9.0 per cent) fermented lactose. All the isolates showed considerable degree of homogeneity in their biochemical and physiological properties, some characters define them to be closer to El Tor biotype.

Expression of L protein of vesicular stomatitis virus Indiana serotype from recombinant baculovirus in insect cells: requirement of a host factor(s) for its biological activity in vitro

The 241-kDa large (L) protein of vesicular stomatitis virus (VSV) Indiana serotype, a multifunctional catalytic subunit of the viral RNA polymerase, has been expressed in Spodoptera frugiperda cells infected with recombinant baculovirus BacPAK6-L containing the L gene under the control of a polyhedrin promoter. The recombinant L protein was biologically active and supported viral mRNA synthesis in vitro. When the expressed L protein was purified by phosphocellulose column chromatography, it eluted in two peaks, one at 0.4 M NaCl (peak I) and the second at 0.75 M NaCl (peak II). The L protein in peak I showed significant transcriptional activity in an in vitro transcription reconstitution experiment, whereas the L protein in peak II was inactive. Interestingly, the addition of cytoplasmic extract from uninfected Sf21 cells to peak II completely restored transcription in vitro, indicating the requirement of a host factor(s) for the activity of the L protein. This factor is relatively heat stable and is dissociable from the recombinant L protein. It is also present in BHK, COS, and HeLa cells in detectable levels. The role of the putative host protein(s) in the activation of the L protein is discussed.

c-myc oncogene expression and cell proliferation in mixed oligo-astrocytoma

Mixed gliomas (oligo-astrocytomas) are brain tumours with an admixture of 2 different cell populations: astrocytes and oligodendroglia. On the basis of histological features and behaviour, these tumours are classified as low-grade mixed gliomas (MG) and malignant mixed gliomas (MMG). We have studied the relationship between c-myc protein expression and cellular proliferation in this class of tumours. Using antibody c-33 for c-myc and PC-10 for the proliferating cell nuclear antigen (PCNA), immunohistochemistry was performed on 14 MG and 9 MMG. PCNA was increased in MMG as compared to MG in both astrocytic and oligodendroglial areas. However, more c-myc-positive cells were seen only in the astrocyte areas of MMG. Analysis of the relationship of c-myc and PCNA suggests that the correlation of c-myc with cellular proliferation is dependent on tissue type and differentiation status.

Management of metastatic Wilms tumor: an eleven year experience

During the last 11 years, 101 patients of Wilms tumor were seen. Of these, 13 patients had metastatic disease at onset while 24 patients presented with relapse at a latter date. Seven patients have been cured, all had favourable histology. The risk factors associated with relapse were found to be unfavourable histology, lymph node involvement, age more than 6 years, diffuse spill, capsular and vascular invasion, and aneuploidy. Of the 18 patients who had relapsed, 14 were found to be aneuploid. Judicious use of various therapeutic options like radiotherapy to metastatic sites, second look surgery, resection of pulmonary metastasis and use of cis-platinum, VP-16 and Ifosfamide as "alternative chemotherapy protocols" were used to achieve cure in these advance cases.

Cluster of cases of clinical cholera due to Vibrio cholerae 010 in east Delhi

A total of 514 samples of acute diarrhoeal stools received over a period of four months yielded 315 isolates morphologically and biochemically resembling V. cholerae. Out of 315 isolates, 223 (70.8%) were identified as V. cholerae 01, 20 (6.4%) as 0139 and 42 (13.3%) as 010. Thirty (9.5%) isolates did not agglutinate with any of the available antisera. All V. cholerae 010 isolates showed complete homogeneity in their biochemical and physiological properties. This strain appears to be closely related to El Tor biotype of V. cholerae 01, since it was positive for some of the tests used for identification of El Tor. The ability of strain 010 to grow in the presence of 6 per cent salt provides it the status of an important environmental pathogen. Acquisition of some virulence genes from El Tor vibrios by this strain 010 appears to be one of the mechanisms involved in the emergence of this serogroup.

Microscopic colitis is a cause of large bowel diarrhea in Northern India

Chronic diarrhea is a common clinical problem. To determine the possible causes in North India, we studied prospectively 71 patients with chronic diarrhea of the large bowel type. A definite diagnosis could be established in 70 patients. Ulcerative colitis was found in 18 patients, colorectal malignancies in three, colonic polyps in three, and irritable bowel syndrome in 32. In addition, seven patients with seronegative polyarthritis and chronic diarrhea were found to have chronic inflammation of the colon on histology. Two patients had pseudodiarrhea, and no diagnosis could be established in one patient. The remaining five patients with chronic diarrhea showed histologic evidence of chronic colonic inflammation with predominantly mononuclear cell infiltration of the lamina propria and increased intraepithelial lymphocytes, but results of their radiologic and endoscopic studies were normal. These five patients were classified as having microscopic (lymphocytic) colitis. We conclude that the causes of chronic diarrhea in North India patients are similar to a large extent to those seen in Western populations. Microscopic (lymphocytic) colitis is a definite clinicopathologic entity that should be considered in the differential diagnosis of chronic diarrhea.

Constitutive activation of a single effector pathway: evidence for multiple activation states of a G protein-coupled receptor

A cysteine-to-phenylalanine mutation in the third transmembrane domain of the alpha 1B-adrenergic receptor constitutively activates the receptor, resulting in G protein coupling in the absence of agonist and activation of only a single effector pathway (phospholipase C but not phospholipase A2). This mutant receptor displays a higher affinity for the catecholamines, norepinephrine, and epinephrine, as well as for other phenethylamines, but not for imidazolines, a class of structurally distinct alpha agonists. Dose-response studies demonstrate a higher potency and intrinsic activity of phenethylamines for polyphosphoinositide turnover but not for arachidonic acid release. Imidazolines have wild-type potencies and intrinsic activities for both pathways. These data indicate that a single receptor subtype forms multiple conformations (i.e., exhibits induced conformational pleiotropy) for G protein interactions (high affinity states) that are specific for a particular G protein/effector pathway and that multiple binding sites exist for agonists, which promote or induce these specific interactions. Pharmacological diversity may, thus, be achieved through a single receptor by the development of compounds that induce a single activated conformer. This has major ramifications for the eventual development of signaling-specific therapeutics.

Prognostic significance of argyrophilic nucleolar organizer regions (AGNOR) in oesophageal cancer

AgNOR (Argyrophilic nucleolar organiser region) has been shown in recent times, to have value in knowing the prognosis of carcinoma oesophagus. We have evaluated the significance of AgNOR in oesophageal cancer with reference to prognosis following treatment. Fifty patients of histologically proven squamous cell carcinoma of the oesophagus were studied. Following oesophagectomy the specimens removed were evaluated for AgNOR number. Of the resected specimens, 25 (50%) had an AgNOR count < or = 3.0, 18 (36%) had an AgNOR count of more than 3 per nucleus and in the remaining 7 cases, AgNOR number was not quantifiable due to the total absence of tumour tissue in the postoperative specimen due to preoperative radiotherapy. When followed up for an average period of 25 months (3 to 47 months), it was seen that patients with AgNOR count of < or = 3.0 per nucleous had a similar mean survival (30.39 +/- 3.29 months) as those with counts > 3.0 per nucleus (27.80 + 3.33 months). The survival in the seven patients in whom no tumour was present following preoperative radiotherapy, was 30.30 +/- 2.42 months. An analysis was done for the presence of change in the AgNOR count before and after radiotherapy in twenty eight case of carcinoma oesophagus treated with preoperative radiotherapy. It was found that the counts on an average were lower in patients after radiotherapy (2.89 +/- 1.04 per nucleus), than before radiotherapy (3.17 +/- 9.69). This was found in 24 cases, while the remaining 4 cases showed no change in count after radiotherapy. This suggested that radiotherapy caused a reduction in AgNOR counts. Mean survival in those with decreased count after radiotherapy was 33.65 (+/- 3.35) months. Since the AgNOR counting is a simple method and can be applied to paraffin embedded section, estimation of the AgNOR number may help in determination of prognosis in patients with oesophageal carcinoma. Preoperative radiotherapy seems to decrease AgNOR count with improved survival. These observations need however, to be reproduced with a larger sample size.

Infrequent alteration of the c-myc gene in human glial tumours associated with increased numbers of c-myc positive cells

Twenty five human glial tumours of different grades of malignancy were examined by Southern blotting and polymerase chain reaction (PCR) for alterations (rearrangements, amplification and deletions) in the c-myc gene. Number of c-myc positive cells per thousand cells were also counted in all the tumours after immunohistochemical staining for c-myc protein was done on fixed sections of the tumours. No tumours exhibited any amplification of the gene, as found by Southern blotting. One astrocytoma and one mixed glioma showed some rearrangements in the 3' end of the gene, as detected by Southern blotting and hydridization. These two tumours had higher number of c-myc positive cells than in other tumours of the same histopathological groups. Deletion in the first promoter region, as determined by PCR, was seen in only one astrocytoma. However, the number of c-myc positive cells in that tumour did not show any deviation from that found in other astrocytomas. In light of present literature, it is speculated that the 3' rearrangements may be the cause of increased number of c-myc immunopositive cells in those tumours by disrupting the 3' end of the gene leading to increased c-myc mRNA stability. Such a mechanism may play a part in small subset of glial and possibly other tumours.

Nosocomial outbreak of Salmonella typhimurium infection in a nursery intensive care unit (NICU) and paediatric ward

A nosocomial outbreak of multidrug resistant Salmonella typhimurium in a Nursery Intensive Care Unit (NICU) and Paediatric ward is reported. Eight (16.6%) out of a total of 48 babies taken ill during this outbreak expired. Clinical manifestations included diarrhoea and fever. The organism was isolated from stool samples/rectal swabs of all the 48 cases and blood of 6 cases. An investigation was undertaken to trace the source of infection. The organism was isolated in pure cultures from three suction machines of NICU. The epidemic was immediately controlled with identification of the source but the question of how the suction machines were infected by this organism remained unsolved.

Diarrhoeal outbreak of Vibrio cholerae 0139 from north India

Epidemics of cholera caused by Vibrio cholerae 01 occur regularly in India. Until recently, Vibrio cholerae non-01 have been the the causative agents of sporadic cases of gastroenteritis and septicaemia, especially in immunocompromised children. We describe a large outbreak of cholera-like illness from North India caused by Vibrio cholerae non-01, later serotyped as Vibrio cholerae 0139. Forty-one of a total of 391 patients with acute diarrhoea during a 2-month period (May-July 1993) were identified as having Vibrio cholerae in faecal samples. All patients were aged 1.5-12 years. Vibrio cholerae 0139 was isolated in 30 patients (73%-group I) and Vibrio cholerae 01 biotype eltor in 11 patients (27%-group II). The clinical presentation and severity of the cholera-like illness were similar to typical cholera. This strain is toxigenic with an epidemic potential and should be monitored carefully.

A correlative study of in vivo and in vitro labeling index using bromodeoxyuridine in human brain tumors

The labeling index (LI) of 216 cases of human brain tumors was determined by the immunohistochemical technique with monoclonal antibody to bromodeoxyuridine (BrdU). The proliferative potential of 110 cases was estimated using the intra-operative intravenous infusion of BrdU at a dose of 200 mg/sq m. In another 106 cases, the in vitro technique of incubating freshly resected tumor tissue fragments with 100 microM bromodeoxyuridine was used. The BrdU LI in these tumors was then correlated with the histological types and the data as determined by both the in vivo and in vitro BrdU incorporation were compared. The results indicate that although in vivo and in vitro techniques could possibly provide equivalent data in some histologic types, a clear statistically valid proof however is not apparent from this study.