Over-expression of inducible heat shock protein 70 in the gastric mucosa of partially sleep-deprived rats

BACKGROUND

Previous findings have demonstrated increased expression of inducible heat shock protein 70 (iHSP70) in the gastric mucosa of rats exposed to partial sleep deprived (PSD). The purpose of this study was to investigate the functional role of iHSP70 and its relationship with acid secretion in the stomachs of PSD animals.

METHODS

A slowly rotating drum was used to induce PSD in male Sprague-Dawley rats with or without omeprazole treatment. Gastric mucosal samples were harvested for iHSP70 mRNA and protein analysis with RT-PCR and Western blotting, respectively. Enzyme immunoassay was used to determine plasma gastrin level and gastric acidity was measured by titration. The modulating effect of PSD on 0.6 M hydrochloric acid (HCl)-induced gastric damage was also evaluated.

RESULTS

PSD increased plasma gastrin, gastric acidity and expression of iHSP70, while significantly reducing HCl-induced gastric damage. Omeprazole administration decreased gastric acidity and reversed iHSP70 over-expression in PSD rats.

CONCLUSIONS

PSD increases gastric acidity which enhances expression of mucosal iHSP70. Over-expression of iHSP70 may be a protective homeostatic response of the stomach to stress induced by PSD and acid secretion.

Reduced expression of chemokine receptors on peripheral blood lymphocytes in patients with hepatocellular carcinoma

OBJECTIVES

Hepatocellular carcinoma (HCC) is a rapidly progressive malignancy. Chemokine receptors are important mediators of lymphocyte migration in cancer. This study evaluated expression of chemokine receptors on lymphocytes of HCC patients.

METHODS

Chemokine receptor expression on peripheral blood lymphocytes (PBL) was determined by flow cytometry and RT-PCR. Tumor infiltrating lymphocytes (TIL) and adjacent nontumor liver infiltrating lymphocytes (NIL) were also studied.

RESULTS

The expressions of CCR5, CCR6, and CXCR3 on PBL were significantly reduced in HCC patients compared with normal controls, which occurred concurrently with increased expression of the chemokine receptors in TIL and NIL. Reduced expression of CXCR3 on PBL correlated with large tumor size and advanced tumor stage. The reduced chemokine receptor expression was consistent with the reduced mRNA levels and intracellular protein levels in PBL. HCC patients exhibited lower proportions of CD4(+) and CD8(+) T cells with CCR5, CCR6, and CXCR3 expression on PBL, which occurred concurrently with the increased expression of these chemokine receptors on TIL and NIL. The reduced CCR6 and CXCR3 expression on PBL correlated with the reduced memory phenotype in circulation and increased memory phenotype in liver. Furthermore, CCR5-expressing memory T cells were increased in liver compartment compared with circulation.

CONCLUSION

This study demonstrated that reduced chemokine receptor expression on PBL was concurrent with increased chemokine receptor expression on both TIL and NIL in HCC. The results demonstrated the role of chemokine receptors in recruitment of lymphocytes from peripheral blood to HCC. The findings have important implications in understanding of immunopathogenesis of HCC.

Different Testicular Gene Expression Patterns in the First Spermatogenic Cycle of Postnatal and Vitamin A-Deficient Rat Testis1

Spermatogenesis is a complicated process of germ cell differentiation, involving programmatic expression of diverse cell type- and developmental stage-specific genes. To date, the vitamin-A-deficiency (VAD) rats and postnatal rats are two models commonly used to study spermatogenesis. In the present study, we studied the expression of 1185 known genes in the vitamin-A-deficient and retinol-reinitiated spermatogenesis of rat testis using Clontech Atlas rat cDNA expression arrays. The mRNA expression patterns of post-vitamin-A (PVA) testis on Days 15 and 35 were compared with those of the spermatogenic arrested rat testis on Day 0. About 9% (110/1185) of the genes studied were highly expressed. When compared with VAD rat testis on Day 0, 20 and 31 genes were differentially expressed by a factor of twofold or greater on Days 15 and 35, respectively. Four genes (cytochrome P450 17, sulfated glycoprotein 2, protein kinase inhibitor, and cathepsin L) that play important roles in spermatogenesis were selected and their gene expression patterns were confirmed by semiquantitative reverse transcription-polymerase chain reaction. Comparison of the expression patterns of these genes between PVA-VAD and postnatal rat testis in developmentally matched stages revealed substantial differences during the early stages of spermatogenesis. This discrepancy could be caused by either the presence of arrested but mature somatic cells in the PVA-VAD testis that may contribute to a unique gene expression pattern in this model or the direct effect of retinol on spermatogenesis. Therefore, caution is needed in interpreting the gene expression data using the PVA-VAD and postnatal rat models in studying spermatogenesis in rat testes.

The Embryotrophic Activity of Oviductal Cell-derived Complement C3b and iC3b, a Novel Function of Complement Protein in Reproduction

The oviduct-derived embryotrophic factor, ETF-3, enhances the development of trophectoderm and the hatching process of treated embryos. Monoclonal anti-ETF-3 antibody that abolishes the embryotrophic activity of ETF-3 recognized a 115-kDa protein from the conditioned medium of immortalized human oviductal cells. Mass spectrometry analysis showed that the protein was complement C3. Western blot analysis using an antibody against C3 confirmed the cross-reactivities between anti-C3 antibody with ETF-3 and anti-ETF-3 antibody with C3 and its derivatives, C3b and iC3b. Both derivatives, but not C3, were embryotrophic. iC3b was most efficient in enhancing the development of blastocysts with larger size and higher hatching rate, consistent with the previous reported embryotrophic activity of ETF-3. Embryos treated with iC3b contained iC3b immunoreactivity. The oviductal epithelium produced C3 as evidenced by the presence of C3 immunoreactivity and mRNA in the human oviduct and cultured oviductal cells. Cyclical changes in the expression of C3 immunoreactivity and mRNA were also found in the mouse oviduct with the highest expression at the estrus stage. Molecules involving in the conversion of C3b to iC3b and binding of iC3b were present in the human oviduct (factor I) and mouse preimplantation embryo (Crry and CR3), respectively. In conclusion, the present data showed that the oviduct produced C3/C3b, which was converted to iC3b to stimulate embryo development.

Identification of liver-intestine cadherin in hepatocellular carcinoma--a potential disease marker

Liver-intestine cadherin (LI-cad) is a non-classical cadherin, which is expressed during intestinal development, but absent in normal liver tissue. Our earlier investigation has detected overexpression of LI-cad in gastric adenocarcinoma and indicated its association with lymph node metastasis. Herein, we found in RT-PCR and TaqMan Q-PCR that LI-cad was identified in HCC cell lines, HuH-7, Hep-3B, and PLC/PRF/5, but not in MIHA and HepG2 non-tumorigenic cells. Immunofluorescence cytochemistry assay revealed that the LI-cad was predominantly expressed in cytoplasm of HCC cells, contrary to that of E-cad immunostain at the plasma membrane region. By testing against 18 pairs of HCC and adjacent non-tumor tissues, 13 cases (72.2%) showed over expression of LI-cad in HCC tissues, 2 cases (11.1%) were similar, and 3 cases did not yield detectable signal. None of the 6 normal liver specimens tested was positive with LI-cad. Taken together, LI-cad could be a potential disease marker for HCC.

Minimally invasive endoscopic-assisted parathyroidectomy for primary hyperparathyroidism

BACKGROUND

Minimally invasive surgery for primary hyperparathyroidism (pHPT) depends on both an accurate preoperative localization and the availability of intraoperative parathyroid hormone monitoring.

METHODS

Patients with sporadic pHPT and one unequivocally enlarged parathyroid gland on preoperative imaging underwent endoscopic-assisted parathyroidectomy. Intraoperative rapid parathyroid hormone (quick PTH) monitoring was performed, and surgical success was confirmed when there was a >50% decrease in quick PTH level 10 min after excision as compared with the baseline level at induction. The surgical outcome and the use of preoperative localization, together with the role played by quick PTH assay in enhancing the operative success, were evaluated.

RESULTS

From 1999 to 2002, 66 of 107 patients (62%) were selected for this approach. The accuracy of 99mTc-Sestamibi scintigraphy and ultrasonography was 97% and 70%, respectively. Conversion was required in four cases due to technical problems, and four additional patients failed to show a significant decline in quick PTH levels postexcision. Two patients underwent cervical exploration without the finding of any additional pathology, and another two patients had a delayed drop in quick PTH that was confirmed 30 min postexcision. All patients had a solitary adenoma and were cured of hypercalcemia during a median follow-up of 9 months.

CONCLUSIONS

Minimally invasive endoscopic-assisted parathyroidectomy can be performed expeditiously in a select group of patients based on 99mTc-Sestamibi scintigraphy. The use of quick PTH assay can ensure surgical success, but careful interpretation of the results is mandatory.

Identification of novel genes expressed during spermatogenesis in stage-synchronized rat testes by differential display

The molecular mechanism regulating spermatogenesis at different developmental stages remains largely unknown. In a vitamin A-deficiency (VAD) rat model, five distinct histologically defined, stage-synchronized testes: (i) resting spermatogonia and preleptotene spermatocytes at Day 0 of post-vitamin A treatment (PVA); (ii) early pachytene spermatocytes at Day 7 PVA; (iii) late pachytene at Day 15 PVA; (iv) round spermatids at Day 25 PVA; and (v) elongated spermatids at Day 35 PVA were used to study gene expression profiles by mRNA differential display. Twenty-four differentially expressed cDNA fragments were identified and cloned; oligonucleotide sequence analyses indicated that there are 12 novel gene sequences, half of which share no apparent match in current GenBank/EMBL databases. Other 12 VAD clones share sequence homology to membrane channel and transport, transcription and translation, cell cycle and morphogenesis, inducer and transducer, surface or secreted glycoproteins or enzymes, and other miscellaneous molecules. Semi-quantitative RT-PCR analyses against different stages of VAD testes demonstrated: (i) restricted expression of VAD1.2 and 1.3 (novel) on Day 25 PVA when round spermatids form; (ii) escalating pattern of VAD12 (Cx43) in Sertoli cells; and (iii) relative constant levels of VAD4 (A5D3), VAD26.1 (ribonuclease), and VAD27 (GRP8) in spermatogenesis.

Recombinant adeno-associated virus vector: Is it ideal for gene delivery in liver transplantation?

Recombinant adeno-associated virus vector (rAAV) is an effective and safe gene-delivery tool. However, its application in solid-organ transplantation has not been addressed. The present study is designed to introduce human cytotoxic T-lymphocyte-associated antigen 4 immunoglobulin G (hCTLA4Ig) by rAAV (rAAV-hCTLA4Ig) into rat liver grafts to analyze the effects of virus titer, exposure time, and route of administration on transgene expression and possible side effects caused by the gene-delivery approach. Different rAAV-hCTLA4Ig titers were introduced into liver grafts through back-table portal vein perfusion and preserved for a certain time. rAAV-hCTLA4Ig also was administered by intravenous and intramuscular injection. Transgene expression in grafts and plasma was detected by immunohistochemistry and enzyme-linked immunosorbent assay. Intragraft cytokine level was detected by reverse-transcriptase polymerase chain reaction. Anti-hCTLA4Ig antibodies in plasma were detected by flow cytometry. A higher virus titer (1 x 10(12) viral genomes/animal) introduced through back-table portal vein perfusion and a longer preservation time (3 hours) achieved a greater level of transgene expression until day 180. Back-table portal vein perfusion induced a greater level of hCTLA4 expression in plasma than intramuscular or intravenous injection. Increased interleukin-2 and interferon-gamma messenger RNA levels were detected in grafts with rAAV-hCTLA4Ig gene transfer compared with those without virus delivery, but the response was minor. Such a cellular immune response could be suppressed by low-dose FK506 administration during the first 3 postoperative days. Anti-hCTLA4Ig antibodies could be detected in long-term surviving animals, but the extent of humoral response was not severe. This study shows that rAAV can be an effective and safe vector for gene delivery in liver transplantation.

Long-term liver allograft survival induced by combined treatment with rAAV-hCTLA4Ig gene transfer and low-dose FK506

BACKGROUND

Recombinant adeno-associated virus vector (rAAV) is a promising vehicle for gene delivery, but few reports have documented its application in solid organ transplantation. In a rat orthotopic liver transplantation model, we investigated the efficacy of rAAV-mediated human cytotoxic T-lymphocyte-associated antigen 4 and immunoglobulin G (hCTLA4Ig) gene transfer to induce long-term allograft survival.

METHODS

Dark Agouti and Lewis rats were used as donors and recipients, respectively, in six experimental groups: (a) syngeneic control, (b) no treatment, (c) rAAV-green fluorescent protein, (d) rAAV-hCTLA4Ig, (e) low-dose FK506 for 7 days, and (f) rAAV-hCTLA4Ig and low-dose FK506 for 7 days.

RESULTS

The liver allografts were rejected within 10 days when no treatment was given or rAAV-green fluorescent protein was delivered. rAAV-hCTLA4Ig transduction slightly prolonged the survival time to 11 days. Long-term survival was achieved using the combined treatment of rAAV-hCTLA4Ig and low-dose FK506, whereas grafts were rejected on day 33 in the low-dose FK506 group. A sustained hCTLA4 level in plasma was detected in the combined treatment group from day 5 to day 180. On postoperative day 5, combined treatment significantly decreased the interleukin-2 and interferon-gamma protein levels in the grafts and the number of infiltrating B, T, CD25+, CD4+, CD8+, and NK cells.

CONCLUSIONS

This study shows that rAAV-hCTLA4Ig gene transfer combined with low-dose FK506 can achieve long-term liver allograft survival.

Embryotrophic factor-3 from human oviductal cells affects the messenger RNA expression of mouse blastocyst

Our previous results showed that embryotrophic factor-3 (ETF-3) from human oviductal cells increased the size and hatching rate of mouse blastocysts in vitro. The present study investigated the production of ETF-3 by an immortalized human oviductal cell line (OE-E6/E7) and the effects of ETF-3 on the mRNA expression of mouse embryos. The ETF-3 was purified from primary oviductal cell conditioned media using sequential liquid chromatographic systems, and antiserum against ETF-3 was raised. The ETF-3-supplemented Chatot-Ziomek-Bavister medium was used to culture Day 1 MF1 x BALB/c mouse embryos for 4 days. The ETF-3 treatment significantly enhanced the mouse embryo blastulation and hatching rate. The antiserum, at concentrations of 0.03-3%, abolished the embryotrophic effect of ETF-3. Positive ETF-3 immunoreactivity was detected in the primary oviductal cells, OE-E6/E7, and blastocysts derived from ETF-3 treatment. Vero cells (African Green Monkey kidney cell line), fibroblasts, and embryos cultured in control medium did not possess ETF-3 immunoreactivity. The mRNA expression patterns of the treated embryos were studied at the blastocyst stage by mRNA differential display reverse transcription-polymerase chain reaction (DDRT-PCR). The DDRT-PCR showed that some of the mRNAs were differentially expressed after ETF-3 treatment. Twelve of the differentially expressed mRNAs that had high homology with cDNA sequences in the GenBank were selected for further characterization. The differential expression of seven of these mRNAs (ezrin, heat shock 70-kDa protein, cytochrome c oxidase subunit VIIa-L precursor, proteinase-activated receptor 2, eukaryotic translation initiation factor 2beta, cullin 1, and proliferating cell nuclear antigen) was confirmed by semiquantitative RT-PCR. In conclusion, immortalized oviductal cells produce ETF-3, which influences mRNA expression of mouse blastocyst.

Applicability of intraoperative parathyroid hormone assay during thyroidectomy

OBJECTIVE

To evaluate the applicability of intraoperative parathyroid hormone (quick PTH) assay to monitor parathyroid function and to identify clinically significant hypocalcemia compared with postoperative serum calcium monitoring.

SUMMARY BACKGROUND DATA

Close monitoring of serum calcium levels is a standard of care to identify post-thyroidectomy hypocalcemia due to parathyroid insufficiency.

METHODS

Quick PTH assay was performed before and after thyroidectomy for 100 patients at risk of postoperative hypocalcemia and 20 control patients who underwent unilateral lobectomy. Postoperative serum calcium levels were closely monitored.

RESULTS

Control patients had a normal but 38.9 +/- 5.9% (mean +/- SEM) decline in quick PTH after thyroidectomy. Eleven of 100 at-risk patients (11%) developed postoperative hypocalcemia. Hypocalcemic patients had significantly lower quick PTH values after thyroidectomy compared with that of normocalcemic patients. Serum calcium was significantly lower in hypocalcemic patients the morning after operation but not early after the operation (within 6 hours). A normal or less than 75% decline in quick PTH after thyroidectomy can accurately identify normocalcemic patients during surgery as compared to more than 24 hours by serum calcium monitoring.

CONCLUSIONS

The quick PTH assay can monitor parathyroid function during thyroidectomy and identify patients at risk of clinically significant hypocalcemia much earlier than serum calcium monitoring. It may facilitate early discharge and the use of parathyroid autotransplantation during thyroidectomy.

Telomerase activity in small cell esophageal carcinoma

Small cell carcinoma of the esophagus is a rare and aggressive malignant tumor. Telomerase activation is common in human cancers. There is a lack of data on telomerase activity in esophageal small cell cancers. The present report studied the role of telomerase activity in esophageal small cell carcinoma. The clinicopathologic data of five patients with small cell carcinoma of the esophagus who underwent primary surgical treatment between 1991 and 2000 were studied. Telomeric repeat amplification protocol assays were used to investigate telomerase activity in these tumors. The proliferative activity (MIB-1) and p53 expression of these tumors were also studied using immunohistochemistry and correlated with the telomerase activity. All five small cell carcinomas showed detectable telomerase activity in the primary tumor. Two out of the five morphologically normal esophageal mucosae adjacent to the primary tumor had detectable telomerase activity. There was no correlation between the p53 expression, tumor stage, survival of patients, and the presence of telomerase activity. High MIB-1 expression in esophageal small cell carcinomas was associated with high telomerase activity. Telomerase activation is common in small cell carcinoma of the esophagus. This fact may find application in anti-telomerase treatment for this aggressive tumor.

Oesophageal basaloid squamous cell carcinoma: a unique clinicopathological entity with telomerase activity as a prognostic indicator

Oesophageal basaloid squamous cell carcinoma (BSCC) is uncommon and has been reported to have a worse prognosis than squamous cell carcinomas (SCCs), but this tumour has not been fully characterized. The aim of the present study was to analyse the clinicopathological features of a large cohort of patients with oesophageal BSCC treated at a single institution. The pathology of 756 primary oesophageal cancers treated between January 1989 and December 1998 was reviewed. Tumours that fulfilled the diagnostic criteria of BSCC were identified and were compared with SCC. Their expression of MIB-1, DNA ploidy, and telomerase activity were also studied. Thirty Chinese patients (25 men and five women) with BSCC were found, comprising 4% of patients with oesophageal cancer treated by surgical resection in the study period. Their median age was 67 years (range 40-78 years). Dysphagia was usually the main presenting symptom. Other concomitant malignant tumours were seen in three patients and paraneoplastic glomerulopathy in one. Five tumours were located in the upper third, 19 in the middle third, and six in the lower third. The median length was 5.8 cm (range 2-12 cm). The median MIB-1 score of BSCC was 750 (range 400-858) and was higher than that of SCC (p=0.003). The primary tumour and metastatic BSCC were aneuploid, as detected by flow cytometric analysis in nine patients. Telomerase activity was positive in 95% (19 out of 20) of the cases analysed. The 5-year survival of patients with BSCC was 12%. Distant metastases were seen in 53% (n=16); lung and liver were the most common sites. The median survival of patients with tumours which had a high level of telomerase activity was significantly shorter than those with low levels of telomerase activity (1 vs. 27 months) (p=0.001). The median survival of patients with BSCC and SCC was 26 and 16 months, respectively (p=0.3). In conclusion, BSCC has distinctive clinicopathological features and its long-term prognosis is no worse than SCC. The level of telomerase activity may have a prognostic role.

The clinicopathological features and importance of p53, Rb, and mdm2 expression in phaeochromocytomas and paragangliomas

AIMS

Phaeochromocytomas and paragangliomas are uncommon. The aims of this study were to analyse the characteristics and the possible roles of p53, Rb, and mdm2 alterations in these tumours.

METHODS

The clinicopathological features of 65 patients (31 men, 34 women) with phaeochromocytomas or paragangliomas were analysed. The tumours were studied for the expression of p53, Rb, and mdm2 by immunohistochemical methods.

RESULTS

Thirty nine of the patients had phaeochromocytomas and 26 had paragangliomas. Bilateral tumours were noted in eight of the patients and malignant tumours were seen in 13. Paragangliomas were often small, non-functional, and presented incidentally, whereas phaeochromocytomas were usually large, functional, and symptomatic. p53 overexpression, loss of Rb expression, and mdm2 overexpression were seen in four, 43, and 37 of the patients, respectively. Three of the four patients with p53 overexpression had bilateral tumours. Loss of Rb expression was often found in phaeochromocytomas, whereas mdm2 overexpression was more frequently seen in paragangliomas. The 10 year survival rate of patients with malignant tumours was 45%. Two patients died of tumour metastases more than 10 years after resection of the primary tumours.

CONCLUSIONS

Phaeochromocytomas and paragangliomas had distinctive clinical features and genetic alterations. The prognosis of patients with these tumours was related to the malignant potential. p53 overexpression, more common in bilateral phaeochromocytomas and paragangliomas, could be a marker for this tumour subgroup.

Suppression of cytokine production and cell adhesion molecule expression in human monocytic cell line THP-1 by Tripterygium wilfordii polysaccharide moiety

Extracts of the vine-like plant Tripterygium wilfordii (TW) have been widely used in China as an immunosuppressant and anti-inflammatory drug for the treatments of rheumatoid arthritis, lupus erythematosus and other inflammatory disorders. In this study the molecular mechanisms of action of three TW extracts (ethanol, aqueous, polysaccharide) on the expression of inflammatory cytokines and adhesion molecules were investigated by RT-PCR and immunofluorescence binding techniques. The lipopolysaccharide (LPS)-mediated stimulatory effects of tumor necrosis factor-alpha (TNF-alpha) cytokine production and cell adhesion molecule (CD11c, CD18, CD14, CD54) expression in human monocytic THP-1 cells were modulated by treatments of the TW extracts or tacrolimus (FK506). The TW polysaccharide moiety exhibited more profound immunosuppressive properties than the aqueous and ethanol extracts. Biochemical characterization of the polysaccharide moiety revealed a major molecular weight of 22 kDa (viz. PSP22). The PSP22 was found to be a potential immunosuppressant that manifests the necessary immunomodulating properties.

Telomerase activity in pancreatic endocrine tumours: a potential marker for malignancy

AIMS

Telomerase activation is known to be a common event in human cancer and may be a useful marker for malignancy. In general, the histological features of pancreatic endocrine tumours cannot be used to determine their malignant potential. The aim of this study was to investigate the role of testing telomerase activity in pancreatic endocrine tumours.

METHODS

Prospectively collected fresh frozen tissue specimens from 10 patients with pancreatic endocrine tumours (nine insulinomas, one adrenocorticotrophin producing pancreatic endocrine tumour) were examined by a highly sensitive polymerase chain reaction (PCR) based telomerase repeat protocol (TRAP).

RESULTS

Of the 10 pancreatic endocrine tumours, three had telomerase activity. The positive cases included two frankly malignant tumours with liver metastases and one pancreatic endocrine tumour occurring in the setting of multiple endocrine neoplasia type 1. The latter had an infiltrative border. Vascular and perineural tumour infiltration was noted. In the two malignant pancreatic endocrine tumours with liver metastases, telomerase activity was noted in the tumour and the adjacent morphologically non-neoplastic pancreas.

CONCLUSION

To our knowledge, this is the first report of the role of telomerase activity in pancreatic endocrine tumours. Telomerase activity might be useful for distinguishing between benign and malignant pancreatic endocrine tumours.

Evaluation of quantitative PCR and branched-chain DNA assay for detection of hepatitis B virus DNA in sera from hepatocellular carcinoma and liver transplant patients

This study evaluated the applicability of quantitative PCR (Q-PCR) and branched-chain DNA assays for detection of hepatitis B virus (HBV) DNA in sera. For 42 samples, the detection rates were 81 and 41%, respectively, with a correlation coefficient of 0.633. The Q-PCR is useful for early monitoring of HBV load in high-risk patients.

Two murine monoclonal antibodies against serogroup E Salmonellae

A monoclonal antibody (MAb), MO15, was raised against the lipopolysaccharide antigen of an epsilon15-lysogenized serogroup E(1) Salmonella strain. The O factor 15-specific MAb MO15, together with another serogroup E-specific MAb, can differentiate among phage lysogenization variants in serogroup E salmonellae. Their epitope specificities in relation to conventional O-antigenic structures are discussed.

Molecular biology of gastric carcinoma: from laboratory to bedside

Although the advancement of molecular oncology in gastric cancer lags behind that of colorectal cancer, the rapid developments witnessed in recent years have improved our understanding of the carcinogenesis, aetiology, progression and metastasis of gastric cancer. The different molecular genetic alterations in intestinal and diffuse types of gastric cancer have further supported the concept that these two pathological types are different disease entities. The association of telomerase and cadherin changes with Helicobacter pylori infection reinforces its aetiological role. The mutated cadherin gene identified in familial gastric cancer has shone light onto the pathogenesis. Adhesion molecules have already been applied to daily clinical practice as prognostic markers. Future molecular studies will contribute to the screening, classification, disease monitoring and therapeutics of gastric cancer.

Telomerase activity in thyroid malignancy

Telomerase activity seems to play a role in the development and pathogenesis of thyroid carcinoma. Its incidence of expression and its application as a tumor marker remain to be elucidated. Thyroid tissues obtained during thyroidectomy from 1996-1998 were rapidly frozen and stored at -80 degrees C until processed. Telomerase activity was determined using telomeric repeat amplification protocol (TRAP). Histology of the tissue examined (67 benign and 59 malignant) was reviewed. Telomerase activity was detected in 15 of 52 papillary carcinomas (29%); 1 of 1 thyroid lymphoma (100%); 1 of 2 anaplastic carcinomas (50%); and 2 of 16 lymphocytic thyroiditis specimens (13%). Telomerase activity was not detectable in 35 normal thyroid, 9 follicular adenoma, 7 nodular hyperplasia, 2 follicular carcinoma, and 2 medullary carcinoma. Lymphocytic thyroiditis was detected in 8 of 37 (22%) apparently normal thyroid tissues adjacent to papillary thyroid carcinoma and telomerase activity was present in 2 of these 8 specimens (25%). In conclusion, telomerase does not appear to be frequently activated in papillary thyroid carcinoma. The association of lymphocytic thyroiditis with papillary thyroid carcinoma may limit its clinical usefulness as a tumor marker.

Differential expression of gap-junction gene connexin 31 in seminiferous epithelium of rat testes

Spermatogenesis, a tightly regulated developmental process of male germ cells in testis, is associated with temporal and spatial expression of certain gap-junction connexins. Our findings by RT-PCR indicate that the Cx31 gene is expressed in testis tissue of adult and postnatal rats. During the postnatal spermatogenic process, the Cx31-specific signal became detectable at 15 dpp and onward by in situ hybridization, and apparently localized in the basal compartment of seminiferous epithelium where active spermatogonia and early primary spermatocytes reside. No signal was found in the luminal region. In adult testes, spermatids of elongation phase were also Cx31 positive. Immunohistochemical analysis with mouse anti-Cx31 antibody gave a similar staining pattern, providing further evidence that the gap-junction protein is abundant in the basal seminiferous epithelium, in accordance with the cellular distribution of Cx31 mRNA. These results represent the first demonstration of Cx31 expression at both transcriptional and protein levels in the seminiferous epithelium of rat testes. Thus, Cx31 may play a role in cell-cell communication during spermatogenesis.

In situ gene transfer into rat auxiliary liver transplant

BACKGROUND

A replication-defective retrovirus BAG vector was tested for in situ delivery of the beta-galactosidase gene to auxiliary liver transplant in a rat model.

METHODS

The BAG vector, which was shown to be effective in genetic transduction of cultured NIH/3T3 cells, was produced in a psi2 packaging cell and later amplified in a selected PA317 clone. Hepatocyte replication was induced by one-third hepatectomy of the donor liver, and the procedure was followed by auxiliary partial liver transplantation. Twenty-four hours after hepatic induction or transplantation, viral supernatant at 37 degrees C was perfused into the liver graft via the portal vein during a temporary occlusion of the graft portal vein.

RESULTS

All animals survived the transplantation procedures and were killed at specified time intervals. Histochemical staining of the liver graft specimens indicated the expression of beta-galactosidase in the gene transferred group but not in the control animals. As demonstrated by polymerase chain reaction assay, the proviral beta-galactosidase sequence was present in the graft specimens, but absent from all other tissues tested.

CONCLUSIONS

In short, the retrovirus BAG vector can be useful for in situ delivery of foreign genes to liver graft in transplantation and other clinical settings, providing a simple, consistent, and reliable alternative in hepatic gene therapy experiments.

Signaling mechanisms of pertussis toxin-induced myelomonocytic cell adhesion: role of tyrosine phosphorylation

Pertussis toxin (PTX) was thought to bind Mac-1 integrin receptor (CD11b/CD18) on TGF-beta1/D3-primed U937 cells and induced cellular adhesion to serum-coated plate. The present study was to investigate the signal transduction pathway utilized by PTX to initiate myeloid cell adhesion in serum. Immunoblotting study showed that PTX induced tyrosine phosphorylation of two cytoplasmic proteins of 150 kDa and 90 kDa in TGF-beta1/D3-primed U937 cells in a time-dependent manner. In addition, PTX-induced myelomonocytic cell adhesion was abolished in the presence of genistein (100 microM), a specific tyrosine kinase inhibitor. 2LPM19c (2 microg/ml), a mouse monoclonal antibody against the CD11b subunit of Mac-1 integrin, or ethylenediamine tetraacetic acid (EDTA, 5 mM) prevented PTX-mediated U937 cell adhesion. On the other hand, nifedipine (1 microM), a calcium channel blocker, significantly reduced PTX-induced U937 cell adhesion. Taken together, it is suggested that binding of PTX to Mac-1 integrin receptor on primed U937 cells triggers protein tyrosine phosphorylation and, to a lesser extent, Ca(+2) influx, which eventually lead to monocytic cell adhesion in serum.