Structure and activation mechanism of the rice Salt Overly Sensitive 1 (SOS1) Na+/H+ antiporter

Salinity is one of the most severe abiotic stresses that adversely affect plant growth and agricultural productivity. The plant Na+/H+ antiporter Salt Overly Sensitive 1 (SOS1) located in the plasma membrane extrudes excess Na+ out of cells in response to salt stress and confers salt tolerance. However, the molecular mechanism underlying SOS1 activation remains largely elusive. Here we elucidate two cryo-electron microscopy structures of rice (Oryza sativa) SOS1, a full-length protein in an auto-inhibited state and a truncated version in an active state. The SOS1 forms a dimeric architecture, with an NhaA-folded transmembrane domain portion in the membrane and an elongated cytosolic portion of multiple regulatory domains in the cytoplasm. The structural comparison shows that SOS1 adopts an elevator transport mechanism accompanied by a conformational transition of the highly conserved Pro148 in the unwound transmembrane helix 5 (TM5), switching from an occluded conformation in the auto-inhibited state to a conducting conformation in the active state. These findings allow us to propose an inhibition-release mechanism for SOS1 activation and elucidate how SOS1 controls Na+ homeostasis in response to salt stress.

[Occupational stress of air traffic controllers and its influencing factors]

Objective: To investigate the occupational stress status of air traffic controllers (ATC) and analyze its influencing factors. Methods: By using cluster sampling method, 457 ATCs in an air traffic management bureau were selected as the investigation objects. The job content questionnaire (JCQ) and the effort reward imbalance questionnaire (ERI) were used to measure work requirements independent imbalance type and ERI type occupational stress separately and analyze the influencing factors. Results: Of the 457 ATCs, 81.84% (374/457) ATGs had work requirements independent imbalance type of occupational stress and 84.46% (386/457) ATGs had ERI type occupational stress. Univariate analysis showed that the factors of marital status, degree of education, age, length of service, title, job post, family monthly income, views on regular training, occurrence of emergency or unsafe events in last month and monthly night shift frequency had various degrees of influence on the different factor scores of JCQ and ERI (P<0.01) . Logistic regression analysis showed that the level of JCQ type occupational stress of ATCs with junior titles and probationers was higher than those of intermediate/senior titles (P=0.000, 0.000) ; The ERI type occupational stress of probationers and junior titles ATCs was lower than those with intermediate/senior titles (P=0.000) . The ERI and JCQ type occupational stress level of tower post ATCs was higher than that of other two job post ATCs (P=0.001, 0.000, 0.000, 0.000) . The ATCs considering regular training had more disadvantages than advantages showed lower ERI type occupational stress level than those considering more advantages than disadvantages (P=0.000) . The ERI type occupational stress level of ATCs who experienced emergency or unsafe events in last month was higher than those who didn't (P=0.007) . Conclusion: A large proportion of ATCs had occupational stress. Management should adjust its policies and pay were attention to occupational stress of ATLs.

Clinicians' beliefs and attitudes to physical activity and exercise therapy as treatment for knee and/or hip osteoarthritis: a scoping review

OBJECTIVE

To explore clinicians' attitudes and beliefs about physical activity and exercise therapy as treatment for individuals with knee and/or hip osteoarthritis (OA).

METHOD

This was a scoping review, mapping available knowledge about the topic derived from qualitative research designs and methods. A comprehensive search of selected databases (MEDLINE, EMBASE; CINAHL; Web of Science) was conducted and data were analysed thematically.

RESULTS

Twelve articles met inclusion criteria. Thematic analysis identified three interrelated main themes: 1) Understandings of OA and its trajectory and management; 2) Attitudes to activity and exercise as part of OA management; 3) Clinicians' perceived knowledge of and expertise in OA management. Findings highlight that many clinicians involved in knee/hip OA management, particularly general practitioners and physiotherapists, perceive OA to be a low priority 'wear-and-tear' disease with expected progression of symptoms, making joint replacement surgery eventually inevitable. Further, many clinicians appear to lack knowledge about and interest in physical activity and exercise therapy in the management of knee/hip OA, and seem to show uncertainty about the effectiveness and safety of physical activity and exercise therapy on joint health.

CONCLUSION

Clinicians' attitudes and beliefs about physical activity and exercise therapy in OA seem to reflect an outdated narrative which describes OA as a wear-and-tear disease with inevitable disease progression to joint replacement surgery. Clinicians need to adopt a contemporary narrative, which accurately reflects current knowledge and evidence-based practice, thereby ensuring consistent utilisation of exercise therapy as first-line care as recommended in OA guidelines.

Poor survival after resection of early gastric cancer: extremes of survivorship analysis reveal distinct genomic profile

A subset of patients with early gastric cancer demonstrate early recurrence and poor survival despite margin-negative resection. This study used an extremes-of-survivorship approach to identify an association between TP53 hotspot mutations co-occurring with loss of heterozygosity and unexpectedly poor survival in early gastric cancer. This distinct genomic profile may be a novel biomarker of poor survival in patients with completely resected early gastric cancer, and warrants large-scale validation. Promising, validation needed.

[The mechanism of nicotine on human bronchial smooth muscle cell contraction]

Objective: To investigate the molecular mechanism of contractility dysfunction of human bronchial smooth muscle cells induced by nicotine. Methods: Primary human bronchial smooth muscle cells were cultured in vitro. The cells were divided into a control group and a nicotine group which was treated with 10(-5) mol/L nicotine for 48 h and transfected with or without α7nAChR-siRNA (The siNC group, siNC + nicotine group and siα7nAChR + nicotine group). The effects of nicotine on the cell contractile function were examined by collagen gel shrinkage assay. The expressions of α7nAChR and TRPC6 protein in nicotine-treated human bronchial smooth muscle cells were detected by Western blotting. The change of intracellular calcium concentration by nicotine was detected by calcium ion imaging system.Data were analyzed by t test or single factor analysis of variance. Results: The area of collagen gel in the nicotine group (24±8)% was significantly lower than that in the control group (59±14)% (t=3.78, P<0.05). Compared with the control group, the expression of α7nAChR protein in nicotine-induced group (173±16)% was significantly higher than that of controls 100±0)%, t=-6.848, P<0.05. Compared with the siNC group [(72±10)%, (0.79±0.07), (0.41±0.04) and (0.17±0.02) respectively], the collagen gel area of siNC + nicotine group was significantly reduced by (37±10)%. However, the basal calcium level (1.04±0.02), store operated calcium entry level (SOCE, 0.68±0.03) and receptor operated calcium entry level (ROCE, 0.36±0.02) were remarkably elevated in the nicotine treated group (all P<0.05). Furthermore, compared with siNC + nicotine group, the area of collagen gel in siα7nAChR + nicotine group was significantly increased (62±10)%, and the basal calcium level (0.78±0.06), SOCE level (0.39±0.05) and ROCE level (0.15±0.02) were significantly reduced (all P<0.05). Conclusions: Nicotine can increase the expression of TRPC6 protein, SOCE and ROCE level, and increase the intracellular calcium concentration by upregulating the expression of α7nAChR protein, thereby promoting smooth muscle cell contraction.

[Spindle cell lipoma and pleomorphic lipoma: a clinicopathologic analysis of 65 cases]

Objective: To investigate the clinical and pathological features of spindle cell lipoma (SCL) and pleomorphic lipoma (PL) with emphasis on differential diagnosis. Methods: Sixty-five cases of SCL/PL from the archive of Department of Pathology, Fudan University Shanghai Cancer Center, from August of 2006 to June of 2017, were included in the study. Immunohistochemistry by EnVision method, MDM2 gene amplifycation and DDIT3 gene translocation by fluorescence in situ hybridization(FISH) were detected and the literature was reviewed. Results: There were 53 males and 12 females with age ranging from 26 to 82 years (mean, 57 years; median, 59 years). The majority of the lesions occurred in the neck/posterior neck/nuchal region, upper back and shoulder. A small percentage of lesions developed in the extremities, face and trunk, and rarely in the epiglottis, mediastinum, labium majus and perineum. Clinically, the tumor usually manifested as a slowly growing mass or nodule. It was often encapsulated, ranging from 1 to 13 cm (mean, 4.1 cm; median, 3.5 cm) in size. Microscopically, SCL was composed of mature adipose tissue, bland spindle cells and bright eosinophilic "ropey" collagen fibers that varied in proportion. Of 45 SCL, 28 cases (62.2%) were classical, 6 cases (13.3%) were myxoid, 5 cases (11.1%) were fat-poor, 3 cases (6.7%) were fat-free, and 3 cases (6.5%) were pseudoangiomatoid. PL showed similar features as SCL, but was characterized by the presence of scattered floret giant cells. Of 20 PL, 11 cases (55.0%) were classical, 6 cases (30.0%) were mixed SCL/PL, 3 cases (15.0%) were fat-free. Both SCL and PL contained scattered mast cells in the stroma. By immunohistochemistry, the spindle cells in SCL and the floret giant cells in PL showed strong positivity for CD34 (52/52, 100.0%), bcl-2 (24/26, 92.3%) and CD99 (6/6), whereas they were negative for S-100 protein and STAT6. FISH analysis of MDM2 (17 cases) and DDIT3 (4 cases) was negative in all cases. Follow-up information was available in 32 patients (3 to 96 months), with local recurrence in only one patient. Conclusions: SCL and PL belong to the same entity but may exhibit morphological disparities. Of note, the fat-poor and fat-free variants are easily mistaken for other mesenchymal tumors. Attention should be paid in their differential diagnosis.

[Latent tuberculosis infection and associated risk factors among the tuberculosis contacts in one of district in Shanghai]

Objective: To investigate the prevalence of latent tuberculosis infection(LTBI) and associated risk factors among the tuberculosis(TB) contacts in Minhang District of Shanghai. Methods: A self-designed questionnaire was used to acquire socio-demographic information and to assess the degree of exposure to index cases. LTBI screening was performed by T-SPOT.TB assay. Pearson chi-square test and Logistic regression analyses were used to identify the risk factors associated with LTBI among the TB contacts. Results: A total of 137 contacts from 59 mycobacterial (culture) positive pulmonary TB patients were enrolled in this study. In these contacts, there were 54 men and 83 women, with the average age of 42. LTBI was identified in 20% (27/137) of these contacts. Several risk factors were found by logistic analyses in this study. The worse the ventilation in the exposure location was, the more likely to develop LTBI. Contacts aged more than 60 (42.1%) were 3.9 times more likely to develop LTBI than those aged less than 60 (16.1%). Individuals in contact with TB patients for more than 40 h/week(25.8%) had a 4.2 times risk of LTBI as compared to those for less than 40 h/week(6.8%). Conclusion: The prevalence of LTBI was 20% among the TB contacts in this study, highlighting the need of TB screening and intervention among TB contacts.

[Application of whole genome sequencing technology in the epidemiology of tuberculosis]

Objective: To delineate the application of whole genome sequencing technology in the epidemiology of tuberculosis. Methods: From 2009 to 2012, nine Mycobacterium tuberculosis that sharing identical variable number of tandem repeats genotype (VNTR) patterns were reported from two TB cases designated hospitals. Both whole-genome sequencing analysis (WGS) and epidemiologic investigations were performed to describe the transmission patterns of these Mycobacterium tuberculosis. Results: By WGS analysis, two genomic clusters including 7 and 2 Mycobacterium tuberculosis were noticed, respectively. The cluster of 2 cases possessed more than 15 single nucleotide polymorphisms (SNPs) when compared to the cluster of 7 cases and suggesting that the transmission route was independent. The transmission chain based on the SNPs difference showed the process of the propagation direction and the accumulation of drug resistance mutations in each cluster. Conclusion: Using a WGS-based genomic epidemiologic approach, we were able to reconstruct the tuberculosis transmission network, tracing the putative source of the transmission and determining the transmission direction or the missing links.

Effects of different surface modification and contents on municipal solid waste incineration fly ash/epoxy composites

Incineration fly ash, a waste from municipal solid waste incineration plant can be used to replace conventional filler as reinforcing filler to enhance the mechanical strength of a composite. Surface modification was performed on the incineration fly ash before mixing into the soft polymer matrix so as to improve interfacial bond of the filler and epoxy resin. In this study, detailed characterisation of mechanical, morphological and leaching behaviours of municipal solid waste incineration (MSWI) fly ash infused composite has been carried out. Flexural and tensile test was conducted to determine the effect on mechanical properties of the composite by varying the concentration of incineration fly ash filler added into polymer matrix and surface modification of incineration fly ash filler using silane coupling agent and colloidal mesoporous silica (CMS). The results indicated that composite infused with incineration fly ash filler surface treated with CMS shown improvement on the tensile and flexural strengths. In addition, SEM images showed that surface modification of incineration fly ash with colloidal mesoporous silica enhanced the interfacial bonding with polymer resin which explained the improvement of mechanical strength. Leaching test showed result of toxic metals such as Pb, Zn, Fe, Cu, Cr, Cd and Rb immobilised in the polymer matrix of the composite. Hence, the use of MSWI fly ash as reinforcing filler in the composite appears green and sustainable because this approach is a promising opportunity to substitute valuable raw material with MSWI fly ash.

Prevalence of hepatitis A viral RNA and antibodies among Chinese blood donors

Like other developing countries, China was reported to have a relatively high seroprevalence of anti-hepatitis A antibodies (anti-HAV). However, no studies have evaluated the prevalence of anti-HAV and HAV RNA among voluntary blood donors with or without elevated serum alanine transaminase (ALT) levels. Anti-HAV antibodies were detected using an enzyme-linked immunosorbent assay, and reverse transcription quantitative polymerase chain reaction was carried out for detection of HAV RNA. In the current study, we analyzed a total of 450 serum samples with elevated ALT levels (≥40 U/L) and 278 serum samples with non-elevated ALT levels. Seroprevalence rates of anti-HAV were 51.6% in donors with elevated ALT and 41.4% in donors with non-elevated ALT; however, none of the samples was positive for HAV RNA. The results of our study showed lower seroprevalence rates of anti-HAV in blood donors (irrespective of ALT levels) than those in published data on Chinese populations. Although donors with elevated ALT had statistically higher prevalence rates of anti- HAV than did those with non-elevated ALT, none of the serum samples had detectable levels of the active virus. In conclusion, our results demonstrate that the transmission of hepatitis A by blood transfusion will occur rarely.

Identification of conserved microRNAs and their target genes in Nile tilapia (Oreochromis niloticus) by bioinformatic analysis

MicroRNAs (miRNAs) are a class of non-coding RNAs that play important roles in posttranscriptional regulation of target genes. miRNAs are involved in multiple biological processes by degrading targeted mRNAs or repressing mRNA translation in various organisms. Their conserved nature in various organisms makes them a good source of new miRNA discovery using comparative genomic approaches. In the present study, conserved Nile tilapia (Oreochromis niloticus) miRNAs were identified using a bioinformatic strategy based on expressed sequence tag and genome survey sequence databases. A total of 21 new miRNAs were detected and were found to belong to 17 families. Using mature miRNA sequences as queries, potential targets for tilapia miRNAs were predicted using a local BLAST program and the miRanda software. Target proteins identified using miRanda and BLAST analyses included transcription factors and molecules important in metabolism, transportation, immunity, stress-related activity, growth, and development. These miRNAs and their targets in tilapia may increase the understanding of the role of miRNAs in regulating the growth and development of tilapia.

Spinal ephrinB/EphB signalling contributed to remifentanil-induced hyperalgesia via NMDA receptor

Background

One of the major unresolved issues in treating pain is the paradoxical hyperalgesia produced by opiates, and accumulating evidence implicate that EphBs receptors and ephrinBs ligands are involved in mediation of spinal nociceptive information and central sensitization, but the manner in which ephrinB/EphB signalling acts on spinal nociceptive information networks to produce hyperalgesia remains enigmatic. The objective of this research was to investigate the role of ephrinB/EphB signalling in remifentanil-induced hyperalgesia (RIH) and its downstream effector.

Methods

We characterized the remifentanil-induced pain behaviours by evaluating thermal hyperalgesia and mechanical allodynia in a rat hind paw incisional model. Protein expression of EphB1 receptor and ephrinB1 ligand in spinal dorsal horn cord was determined by Western blotting, and Fos was determined by immunohistochemistry assay, respectively. To figure out the manner in which ephrinB/EphB signalling acts with N-methyl-d-aspartic acid (NMDA) receptor, we used MK-801, an antagonist of NMDA receptor, trying to suppressed the hyperalgesia induced by ephrinB1-Fc, an agonist of ephrinB/EphB.

Results

Continuing infusion of remifentanil produced a thermal hyperalgesia and mechanical allodynia, which was accompanied with increased protein expression of spinal-level EphB1 receptor, ephrinB1 ligand and Fos; what appeared above was suppressed by pretreatment with EphB1-Fc, an antagonist of ephrinB/EphB or MK-801, and increased pain behaviours induced by intrathecal injection of ephrinB1-Fc, an agonist of ephrinB/EphB, were suppressed by MK-801.

Conclusions

Our findings indicated that ephrinB/EphB signalling is involved in RIH. EphrinB/EphB signalling might be the upstream of NMDA receptor.

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Goblet cell carcinoid neoplasm of the appendix: clinical and CT features

PURPOSE

To describe the clinical and CT imaging features of goblet cell carcinoid (GCC) neoplasm of the appendix.

METHODS AND MATERIALS

A computer search of pathology and radiology records over a 19-year period at our two institutions was performed using the search string "goblet". In the patients with appendiceal GCC neoplasms who had abdominopelvic CT, imaging findings were categorized, blinded to gross and surgical description, as: "Appendicitis", "Prominent appendix without peri-appendiceal infiltration", "Mass" or "Normal appendix". The CT appearance was correlated with an accepted pathological classification of: low grade GCC, signet ring cell adenocarcinoma ex, and poorly differentiated adenocarcinoma ex GCC group.

RESULTS

Twenty-seven patients (age range, 28-80 years; mean age, 52 years; 15 female, 12 male) with pathology-proven appendiceal GCC neoplasm had CT scans that were reviewed. Patients presented with acute appendicitis (n=12), abdominal pain not typical for appendicitis (n=14) and incidental finding (n=1). CT imaging showed 9 Appendicitis, 9 Prominent appendices without peri-appendiceal infiltration, 7 Masses and 2 Normal appendices. Appendicitis (8/9) usually correlated with typical low grade GCC on pathology. In contrast, the majority of Masses and Prominent Appendices without peri-appendiceal infiltration were pathologically confirmed to be signet ring cell adenocarcinoma ex GCC. Poorly differentiated adenocarcinoma ex GCC was seen in only a small minority of patients. Hyperattenuation of the appendiceal neoplasm was seen in a majority of cases.

CONCLUSIONS

GCC neoplasm of the appendix should be considered in the differential diagnosis in patients with primary appendiceal malignancy. Our cases demonstrated close correlation between our predefined CT pattern and the pathological classification.

Prognosis of metastatic gastric and gastroesophageal junction cancer by HER2 status: a European and USA International collaborative analysis

BACKGROUND

To determine whether human epidermal growth factor receptor 2 (HER2) status is an independent prognostic factor in metastatic gastric and gastroesophageal junction (GEJ) adenocarcinoma.

PATIENTS AND METHODS

Formalin-fixed paraffin-embedded tumor samples from 381 metastatic gastric/GEJ cancer patients enrolled at Krankenhaus Nordwest and Memorial Sloan-Kettering Cancer Centers on six first-line trials of chemotherapy without trastuzumab were examined for HER2 by immunohistochemistry (IHC) and in situ hybridization (ISH). IHC 3+ or ISH-positive tumors were considered HER2 positive.

RESULTS

Seventy-eight of 381 patients (20%) had HER2-positive disease. In the multivariate logistic model, there were significantly higher rates of HER2 positivity in patients with liver metastasis (liver metastasis 31%; no liver metastasis 11%; P = 0.025) and intestinal histology (intestinal 33%; diffuse/mixed 8%; P = 0.001). No significant differences in HER2 positivity were found between resections and biopsies or primaries and metastases. Patients with HER2-positive gastric cancer had longer median overall survival compared with HER2-negative gastric cancer patients (13.9 versus 11.4 months, P = 0.047), but multivariate analysis indicated that HER2 status was not an independent prognostic factor (hazard ratio 0.79; 0.44-1.14; P = 0.194).

CONCLUSIONS

Approximately 20% of Western patients with metastatic gastric cancer are HER2 positive. Unlike breast cancer, HER2 positivity is not independently prognostic of patient outcome in metastatic gastric or GEJ.

An individual coding polymorphism and the haplotype of the SPARC gene predict gastric cancer recurrence

The 5-year survival rate for gastric adenocarcinoma (GA) remains only 40% and biomarkers to identify patients at high risk of tumor recurrence are urgently needed. Secreted protein acidic and rich in cysteine (SPARC) is an extracellular matrix glycoprotein that mediates cell matrix interactions, and upregulation of SPARC can promote tumor progression and metastasis. This study investigated whether single-nucleotide polymorphisms (SNPs) in SPARC impact the prognosis of GA. Blood or formalin-fixed, paraffin-embedded tissues were obtained from 137 GA patients at the University of Southern California and Memorial Sloan-Kettering Cancer Center medical facilities. DNA was isolated and five SNPs in the SPARC 3'-untranslated region (UTR) were evaluated by DNA sequencing or PCR-restriction fragment length polymorphism. Associations between SNPs and time to tumor recurrence (TTR) were analyzed using Kaplan-Meier curves, log-rank tests, and likelihood-ratio test within logistic or Cox regression model as appropriate. Patients carrying at least one G allele of the SPARC rs1059829 polymorphism (GG, AG) showed a median TTR of 3.7 years compared with 2.1 years TTR for patients with AA (hazard ratio (HR) 0.57; P=0.033). In a multivariate analysis adjusted for T and N category as covariates and stratified by race, hospital and chemotherapy, patients with at least one SPARC rs1059829 G allele (GG, AG) remained significantly associated with superior TTR than patients with AA genotype (adjusted P=0.026). In addition, patients harboring the G-A-A haplotype had the highest risk of tumor recurrence (HR 1.892; adjusted P=0.016). Our findings suggest that SPARC 3'-UTR SNPs may be useful in predicting GA patients at increased risk of recurrence.

An individual coding polymorphism and the haplotype of the SPARC gene predict gastric cancer recurrence

The 5-year survival rate for gastric adenocarcinoma (GA) remains only 40% and biomarkers to identify patients at high risk of tumor recurrence are urgently needed. Secreted protein acidic and rich in cysteine (SPARC) is an extracellular matrix glycoprotein that mediates cell matrix interactions, and upregulation of SPARC can promote tumor progression and metastasis. This study investigated whether single-nucleotide polymorphisms (SNPs) in SPARC impact the prognosis of GA. Blood or formalin-fixed, paraffin-embedded tissues were obtained from 137 GA patients at the University of Southern California and Memorial Sloan-Kettering Cancer Center medical facilities. DNA was isolated and five SNPs in the SPARC 3'-untranslated region (UTR) were evaluated by DNA sequencing or PCR-restriction fragment length polymorphism. Associations between SNPs and time to tumor recurrence (TTR) were analyzed using Kaplan-Meier curves, log-rank tests, and likelihood-ratio test within logistic or Cox regression model as appropriate. Patients carrying at least one G allele of the SPARC rs1059829 polymorphism (GG, AG) showed a median TTR of 3.7 years compared with 2.1 years TTR for patients with AA (hazard ratio (HR) 0.57; P=0.033). In a multivariate analysis adjusted for T and N category as covariates and stratified by race, hospital and chemotherapy, patients with at least one SPARC rs1059829 G allele (GG, AG) remained significantly associated with superior TTR than patients with AA genotype (adjusted P=0.026). In addition, patients harboring the G-A-A haplotype had the highest risk of tumor recurrence (HR 1.892; adjusted P=0.016). Our findings suggest that SPARC 3'-UTR SNPs may be useful in predicting GA patients at increased risk of recurrence.

Preoperative chemotherapy does not influence the number of evaluable lymph nodes in resected gastric cancer

BACKGROUND

While it is suggested that more than 15 lymph nodes (LNs) should be evaluated for accurate staging of gastric cancer, LN yield in western countries is generally low. The effect of preoperative chemotherapy on LN yield in gastric cancer is unknown. The aim of the present study is to determine whether preoperative chemotherapy is associated with any difference in the number of LNs obtained from specimens of patients who underwent curative surgery for gastric adenocarcinoma.

PATIENTS AND METHODS

In 1205 patients from Memorial Sloan-Kettering Cancer Center (MSKCC) and 1220 patients from the Netherlands Cancer Registry (NCR) who underwent a gastrectomy with curative intent for gastric adenocarcinoma without receiving preoperative radiotherapy, LN yield was analyzed, comparing patients who received preoperative chemotherapy and patients who received no preoperative therapy.

RESULTS

Of the 2425 patients who underwent a gastrectomy, 14% received preoperative chemotherapy. Median LN yields were 23 at MSKCC and 10 in the NCR. Despite this twofold difference in LN yield between the two populations, with multivariate Poisson regression, chemotherapy was not associated with LN yield of either population. Variables associated with increased LN yield were institution, female sex, lower age, total (versus distal) gastrectomy and increasing T-stage.

CONCLUSIONS

In this patient series, treatment at MSKCC, female sex, lower age, total gastrectomy and increasing primary tumor stage were associated with a higher number of evaluated LNs. Preoperative chemotherapy was not associated with a decrease in LN yield. Evaluating more than 15 LNs after gastrectomy is feasible, with or without preoperative chemotherapy.

GRP78 promoter polymorphism rs391957 as potential predictor for clinical outcome in gastric and colorectal cancer patients

BACKGROUND

Recently, the analysis of gastric and colorectal tumor specimens determined that 78-kiloDalton glucose-regulated protein (GRP78), an endoplasmic reticulum chaperone, up-regulation serves as an efficient mechanism protecting cells against apoptosis and can confer drug resistance. We tested whether functional polymorphisms within the GRP78 gene are related to clinical outcome in gastric and colorectal cancer (CRC) patients.

PATIENTS AND METHODS

Blood samples of 234 stage II/III CRC patients at the University of Southern California (USC) and formalin-fixed paraffin-embedded tissues of 137 patients with localized gastric adenocarcinoma (GA) at USC and Memorial Sloan-Kettering Cancer Centers were obtained. GRP78 polymorphisms analyzed on germline DNA were correlated with clinical outcome using univariate and multivariate analyses.

RESULTS

GA patients with the combined GRP78 rs391957 C/T and T/T genotype were at higher risk for tumor recurrence and death [hazard ratio (HR) 2.61; P < 0.001 and HR 3.17; P < 0.001, respectively], than those with C/C. These findings were subsequently tested in a CRC cohort where patients with the homozygous T/T genotype were at highest risk for tumor recurrence (HR 2.61; P = 0.015). The results remained significant after adjusting for clinicopathologic determinants.

CONCLUSION

These data provide the first evidence that the GRP78 rs391957 polymorphism can predict clinical outcome in localized GA and locally advanced CRC patients.

Genetic variations in angiogenesis pathway genes associated with clinical outcome in localized gastric adenocarcinoma

BACKGROUND

Angiogenesis has been attributed to be a well-recognized aspect of human cancer biology. As such, proteinase-activated receptor (PAR)-1, endostatin (ES) and interleukin-8 (IL-8) mediate the regulation of early-onset angiogenesis and in turn impact the process of tumor-growth and disease progression.

PATIENTS AND METHODS

Formalin-fixed paraffin-embedded tissues were obtained from 137 patients with localized gastric cancer at University of Southern California and Memorial Sloan-Kettering Cancer Center medical facilities. DNA was extracted and genotyping was carried out using PCR-restriction fragment length polymorphism-based protocols.

RESULTS

In false discovery rate-adjusted univariate analysis, PAR-1 -506 ins/del (P < 0.001), ES +4349 G>A (P = 0.004), and IL-8 -251 T>A (P < 0.0001) were associated with time to tumor recurrence (TTR). Further, PAR-1 -506 ins/del and IL-8 -251 were associated with overall survival (OS). After adjusting for covariates, IL-8 remained significantly associated with TTR (adjusted P = 0.003) and OS (adjusted P = 0.049), whereas ES was significantly associated with TTR (adjusted P = 0.026).

CONCLUSIONS

Polymorphisms in PAR-1, ES, and IL-8 may serve as independent molecular prognostic markers in patients with localized gastric adenocarcinoma. The assessment of the patients' individual risk on the basis of interindividual genotypes may therefore help to identify patient subgroups at high risk for poor clinical outcome.

Identification of 17 novel major histocompatibility complex-A alleles in a population of Chinese-origin rhesus macaques

Rhesus macaques (Macaca mulatta) serve as important animal models for human disease and vaccine research. Although Chinese rhesus macaques are the same species as those of Indian origin, they are from a geographically separated population and possess divergent major histocompatibility complex (MHC) class I A alleles. In an analysis of 65 Chinese rhesus macaques, 17 novel Mamu-A alleles were identified and deposited under the following accession numbers: EU252155-158, EU262737-741, EU418504-505, EU422996, EU418506, EU753185-187, and EU828528. The discovery of these additional MHC class I A sequences indicates a greater diversity and polymorphism of Chinese rhesus macaques in different geographic locations. As the set of Mamu-A alleles in Chinese rhesus macaques differs from the alleles of Indian animals, more work still needs to be carried out to identify these new allele-restricted immune responses with regard to vaccine studies.

Influence on intestinal mucous permeation of paclitaxel of absorption enhancers and dosage forms based on electron spin resonance spectroscopy

The aim of this paper is to investigate the permeation mechanism of the hydrophobic drug, paclitaxel in intestinal membranes of mice in relation to enhancers and preparation factors. The alteration fluidity of lipid and protein in mucous membrane were determined using electron spin resonance (ESR) when the membrane was treated with several enhancers including Pluronic F68, polyethylene glycol (PEG), Brij78 and lecithin. At the same time, the enhanced permeation of paclitaxel across the intestinal intercellular membrane of stratum corneum was studied for three formulations: inclusion complex, microemulsion and injection. The results showed that use of paclitaxel-hydroxypropyl-beta-cyclodextrin inclusion complexation and of paclitaxel microemulsion as vehicle and PEG 1500 as enhancer could significantly increase the permeation kinetics of paclitaxel in a fluid diffusion study. The effect on absorption characteristics of enhancing permeation of this hydrophobic drug in the intestinal mucosa was considered in the light of the change in membrane fluid.

A phase II trial of neoadjuvant cisplatin-fluorouracil followed by postoperative intraperitoneal floxuridine-leucovorin in patients with locally advanced gastric cancer

BACKGROUND

The aim of the study was to evaluate the efficacy and toxicity of neoadjuvant chemotherapy with intravenous (i.v.) cisplatin and fluorouracil (5-FU), surgery and postoperative intraperitoneal (i.p.) floxuridine (FUdR) and leucovorin (LV) in patients with locally advanced gastric cancer.

PATIENTS AND METHODS

Preoperative staging was confirmed by laparoscopy (LAP). Two cycles of i.v. cisplatin (20 mg/m(2)/day, rapid infusion) and 5-FU (1000 mg/m(2), continuous 24-h infusion), given on days 1-5 and 29-34, were followed by a radical gastrectomy and a D2 lymphadenectomy. Patients having R0 resections were to receive three cycles of i.p. FUdR (1000 mg/m(2)) and LV (240 mg/m(2)), given on days 1-3, 15-17 and 29-31. Intraperitoneal chemotherapy was begun 5-10 days from surgery.

RESULTS

Thirty-eight patients were treated. Both preoperative and postoperative chemotherapy were well tolerated. T stage downstaging (pretreatment LAP versus surgical pathological stage) was seen in 23% of patients. The R0 resection rate was 84%. Neither an increase in postoperative morbidity nor operative mortality was noted. With a median follow-up of 43.0 months, 15 patients (39.5%) are still alive (median survival 30.3 months). Good pathologic response, seen in five patients (15%), was associated with better survival (P = 0.053). Peritoneal and hepatic failures were found in 22% and 9% of patients, respectively. Quality of life seemed to be preserved.

CONCLUSIONS

Neoadjuvant cisplatin/5-FU followed by postoperative i.p. FUdR/LV can be safely delivered to patients undergoing radical gastrectomy and D2 lymphadenectomy. The R0 resection and the survival rates are encouraging. An association between pathologic response and patient outcome was suggested.

Molecular evidence supports that Anopheles anthropophagus from China and Anopheles lesteri from Japan are the same species

The Hyrcanus group of Anopheles consists of many related species, of which An. sinensis, An. lesteri, and An. anthropophagus are known as malaria vector species. It is not possible to identify these species morphologically in the adult and larval stages. Nucleotide sequence alignment of 2nd internal transcribed spacer (ITS2) regions from 4 specimens of An. lesteri collected in Japan, 2 specimens of An. anthropophagus collected in China, and 1 specimen of An. sinensis collected in Korea were sequenced and compared. Sequences of ITS2 regions varied only at 4 sites between An. lesteri and An. anthropophagus, and individual variations among each An. lesteri and An. anthropophagus were found at 5 and 7 sites, respectively, whereas sequences varied at 161 sites between An. lesteri and An. sinensis. This molecular evidence strongly supports that An. lesteri from Japan and An. anthropophagus from China are the same species.

[The role of Anopheles anthropophagus in malaria transmission in in Xinyang City of Henan Province]

OBJECTIVE

To study the role of Anopheles anthropophagus in malaria transmission and transmission threshold so as to provide basis for vector surveillance and malaria control strategy.

METHODS

Parasitological and entomological methods were used in the investigation at 5 villages of Xinyang City, Henan Province.

RESULTS

From July to August, 1999, 74 febrile cases (10.9% of the total population) were examined. Among them 50 were infected, the incidence in the population of surveyed spots was 7.4%. Active detection was made in another randomly selected two villages and found that the parasite rate in the inhabitants was 2.0%, and the positive rate of IFA was 8.4%. Only vivax malaria was detected. An. anthropophagus and An. sinensis were collected, with An. anthropophagus as the predominant one in human dwellings. The estimated man-biting rate and the human blood index were 4.9388 and 0.7858 respectively. The vectorial capacity of An. anthropophagus was 5.5296. The critical man-biting rate of An. anthropophagus was 0.2407 as calculated by the formula (ma = -rlnP/abPh) according to Macdonald's model. The local man-biting rate was 20 times higher than that of the critical man-biting rate.

CONCLUSION

The results demonstrated that An. anthropophagus is the principal vector in malaria transmission in the area. The findings imply that the critical man-biting rate is of practicable importance in vector surveillance.

[Practicability of IFAT using Plasmodium cynomolgi and Plasmodium falciparum antigens in different malarious areas]

OBJECTIVE

To compare the practicability of IFAT in different malarious areas using Plasmodium cynomolgi(P.c.) and Plasmodium falciparum(P.f.) antigens.

METHODS

This survey was carried out in Yaliang Township of Sanya City, Hainan Province, where a mixed malaria is endemic, and in Tongbo County, Henan Province where only vivax malaria is endemic, and in Weihui City, Henan Province where vivax malaria has been under effective control since 1994-1998.

RESULTS

In Yaliang Township, 310 blood samples were examined, the antibody positive rates with P.c. and P.f. were 37.4% and 31.3%, respectively, the rate of coincidence being 83.9%. In Tongbo County, 300 blood samples were examined. The antibody positive rates with P.c. and P.f. were 23.0% and 9.7%, respectively (P < 0.01). Another 245 blood samples from children were examined in Weihui City and the antibody positive rates were below 1% with two antigens, while the positive antibody rate was 3.3% with P.f. antigen.

CONCLUSION

Both P.f. and P.c. antigens could be used in malaria antibody surveillance in mixted endemic areas, while in vivax malaria endemic areas, P.c. antigen was recommended.

PACAP mediates the neural proliferative pathway of Mastomys enterochromaffin-like cell transformation

BACKGROUND AND AIM

Pituitary adenylate-cyclase activating peptide (PACAP) is a more potent proliferative agent than gastrin for rat enterochromaffin-like (ECL) cell proliferation in vitro. The role of this neurotransmitter during gastrin-mediated ECL cell tumor formation and gastrin-autonomous ECL cell neoplasia is unknown.

METHODS AND RESULTS

ECL cell transformation was induced in the Mastomys using 16 wk H2 receptor blockade of acid inhibition. Examination of the epithelial fundic mucosa demonstrated that PACAP-immunoreactivity significantly increased in the tumor mucosa compared to the naïve stomach, and was associated with ECL cells. Naïve and tumor ECL cells were then purified (approximately 95%) from Mastomys and the presence of all three PACAP/VPAC receptor subtypes was demonstrated by polymerase chain-reaction amplification. Thereafter, cells were maintained in short-term (48 h) primary cultures. PACAP significantly (p<0.05) increased 24 h bromo-deoxyuridine uptake (approximately 4-fold) in both cell types with estimated EC(50) values of approximately 4x10(-16) M and approximately 2x10(-16) M, respectively. Specific receptor antagonists (PAC1/VPAC1) of PACAP competitively inhibited these proliferative effects in naïve cells. Oligonucleotide antisense directed against PAC1 significantly inhibited PACAP-stimulated DNA synthesis by approximately 85% (p<0.05) in tumor cells.

CONCLUSION

PACAP is a potent and effective modulator of ECL cell proliferation. The expression of this neuropeptide and its receptors, particularly PAC1, suggest the existence of a neural regulatory pathway of ECL cell proliferation and transformation.

Anomalous finite-size effect in superconducting Josephson junction arrays

We show that a previously reported discrepancy between simulations of superconducting Josephson junction arrays and the theoretical analysis of Ambegaokar, Halperin, Nelson, and Siggia (AHNS) [Phys. Rev. Lett. 40, 783 (1978)] is rooted in a peculiar finite-size effect under periodic boundary conditions. Our simulation results for the largest array support the power-law I-V curves predicted by AHNS. Analysis of the vortex dynamics reveals two intrinsic length scales set by the applied current, which define three size regimes with distinctive I-V characteristics.

Gastrin-mediated alterations in gastric epithelial apoptosis and proliferation in a mastomys rodent model of gastric neoplasia

BACKGROUND/AIMS

Hypergastrinemia secondary to low acid secretion is associated with gastric carcinoid formation in Mastomys. We investigated the effect of gastrin on oxyntic epithelial apoptosis and proliferation in this model.

METHODS

Hypergastrinemia and mucosal hyperplasia were induced by irreversible H(2) receptor blockade with loxtidine. Gastrin levels were normalised in some animals by 10 days' loxtidine withdrawal. Serum gastrin was determined by radioimmunoassay, proliferative, enterochromaffin-like cells and Bcl-2 protein family expression by immunohistochemistry, and apoptotic cells by terminal deoxyuridine nucleotide nick end labeling (TUNEL).

RESULTS

Proliferating cells were increased 4-fold in loxtidine-treated animals, and returned to normal upon loxtidine withdrawal. Enterochromaffin-like cell number increased 2-fold with loxtidine, and did not decrease after withdrawal. Apoptotic epithelial cells were located at the luminal surface and increased 1.8-fold with loxtidine, returning to control levels upon withdrawal. The ratio of proliferative to apoptotic cells was lower in the control and withdrawn groups than in the loxtidine group (0.26+/-0.05 and 0.26+/-0.08 vs. 0.77+/-0.12). With hypergastrinemia, the expression of Bcl-2 and Bak was increased and Bax decreased in the middle of the gland.

CONCLUSION

Hypergastrinemia is associated with alterations in both proliferation and apoptosis in Mastomys gastric mucosa. This may contribute to the pathogenesis of mucosal hyperplasia in this model.

Helicobacter pylori lipopolysaccharide alters ECL cell DNA synthesis via a CD14 receptor and polyamine pathway in mastomys

Chronic Helicobacter pylori infection is associated with alterations in gastric mucosal cell proliferation. Despite the recognition that bacterial lipopolysaccharide (LPS) is present in biologically active quantities in the gastric mucosa, the mechanisms by which it stimulates cells are largely unknown. We have previously established a gastric enterochromaffin-like (ECL) cell neoplasia model in the African rodent species Mastomys and identified that tumor ECL cell proliferation is associated with polyamine biosynthesis and ornithine decarboxylase (ODC) activity. In addition, we have shown that H. pylori LPS exhibits a specific mitogenic effect on naive ECL cells in vitro. The aim of this study was to evaluate whether H. pylori has a direct effect on tumor ECL cell proliferation in vitro and further to evaluate the possible molecular mechanisms for this effect. ECL cell neoplasia was generated in Mastomys by endogenous hypergastrinemia induced by H(2) blockade (loxtidine 1 g/kg/day) and tumor ECL cells prepared. The DNA synthesis in 24-hour cultured tumor cells was measured by bromodeoxyuridine uptake and ODC activity by (14)CO(2) formation from (14)C-ornithine. The putative LPS receptor, CD14, was evaluated by reverse-transcription polymerase chain reaction. Our results demonstrated: (1) H. pylori LPS (10(-12) to 10(-7) M) stimulated basal DNA synthesis (2.2-fold) with an estimated EC(50) of 10(-10) M; (2) this proliferative response correlated with an increase in ODC activity (1.4-fold, EC(50) approximately 10(-10) M) which could be inhibited by a specific ODC inhibitor, difluoromethyl ornithine, at 10(-9) M; (3) the CD14 receptor was identified in both naive and transformed ECL cells by reverse-transcription polymerase chain reaction, and (4) the effects of LPS were inhibited by blocking the CD14 receptor with its specific monoclonal antibody (1:100). Thus, H. pylori LPS appears to influence tumor ECL cell proliferation by activation of the intracellular polyamine pathway and ODC activity via a CD14 receptor on the ECL cell.

Rare-event induced binding transition of heteropolymers

Sequence heterogeneity broadens the binding transition of a polymer onto a linear or planar substrate. This effect is analyzed in a real-space renormalization group scheme designed to capture the statistics of rare events. In the strongly disordered regime, binding initiates at an exponentially rare set of "good contacts." Renormalization of the contact potential yields a Kosterlitz--Thouless-type transition in any dimension. This and other predictions are confirmed by extensive numerical simulations of a directed polymer interacting with a columnar defect.

A study of injectable tissue-engineered autologous cartilage

OBJECTIVE

To test the effectiveness of the new techniques of tissue-engineered cartilage.

METHODS

Chondrocytes were harvested through type II collagenase digestion from the auricle of New Zealand rabbits. The cells were mixed with alginate to generate chondrocytes/alginate composites with final cellular density of 50 x 10(6) per mL. Calcium chloride was used as the cross-linking agent to gel the aqueous alginate solution. The chondrocytes/alginate composites were injected into the dorsal subcutaneous tissue of New Zealand rabbits through autologous cells grafts. The specimens were observed during cartilage formation at 4, 8, and 12 weeks after injection.

RESULTS

Prior to harvesting, chondrocytes/alginate composites were easily visualized under the dorsal skin of animals. The appearance of experimental specimens was similar to that of native cartilage in gross morphology. Using a standard hematoxylin and eosin stain, the histologic features of all experimental specimens demonstrated new cartilage formation. With a Masson's trichrome and safranin O stain, the presence of collagen and glycosaminoglycan (GAG) was observed at 8 and 12 weeks.

CONCLUSION

This study demonstrated that polymerization of alginate hydrogel can be controlled to allow injection of chondrocytes that produce new autologous cartilage at subcutaneous dorsal site of rabbits. Injectable tissue-engineered autologous cartilage is promising for potential use in oral and maxillofacial surgery.

Gastrin and the enterochromaffin-like cell: an acid update

Gastrin is synthesized and secreted mostly in a heptadecapeptide form from neurocrine G cells located in the antrum. The biologically active sequence of the molecule is a C-terminal pentapeptide, which has been conserved across many species. Transcriptional regulation of gastrin mRNA synthesis is positively regulated by transforming growth factor-alpha (TGF-alpha) and inhibited by somatostatin (SST). The inactive precursor form is converted to the active molecule by several post-translation processing steps which include cleavage, C-terminal amidation, glycosylation, phosphorylation and sulfation. Aberrations in processing steps generate incompletely processed forms, particularly glycosylated progastrin, which may act as autocrine growth factors for gastrointestinal neoplasms. Gastrin release is stimulated by luminal aromatic amino acids and inhibited by a decrease in luminal pH. Other gastrin agonists include beta-adrenergic agents, acetylcholine, gastrin-releasing peptide (bombesin), TGF-alpha, and possibly the gastric pathogen, Helicobacter pylori. The principal peptide inhibitor of gastrin release is SST. The major physiological roles of gastrin include stimulation of acid secretion, regulation of mucosal cell lineage and mucosal cell proliferation. The fundic enterochromaffin-like (ECL) cell is the principal cellular transducer of the gastrin-acid signal. Activation of its gastrin/CCKB receptor results in histamine synthesis and release with consequent activation of the fundic parietal cell H2 receptor. An increase in luminal pH caused by acid inhibitory pharmacotherapy agents (particularly proton pump inhibitors) results in hypergastrinemia and ECL cell hyperplasia. Gastric carcinoids however appear occur in patients with multiple endocrine neoplasia type I syndrome, suggesting that an associated genomic defect is necessary. Gastrin is thus both a potent gastrointestinal trophic and histamine secretory agent. As a hormone it is a paradigm in the elucidation of both cellular secretory and growth factor induced cell proliferation.

[Studies on lipase-catalyzed synthesis of L-ascorbyl palmitate in non-aqueous phase]

The investigation on the reaction media and lipases (NOVO435, MML, LIPOLASE, PPL) for enzymatic synthesis of L-ascorbyl palmitate as well as the factors effecting initial rate of synthesis reaction (rotation speed, temperature, water content, enzyme concentration, and substrate concentration) is presented. Among these investigated solvents and lipases, amyl alcohol and NOVO435 is the optimum pair. The reaction conditions have been optimized: 200 r/min, 55 degrees C, water content = 0, the amount of enzyme = 12.5% of the substrate's quantity.

[Multi-bed & multi-parameter central monitoring system based on TCP/IP protocol]

Communication is one of the key problems to a central monitoring system. In this paper we put forward a central monitoring system using TCP/IP as the network protocol, Windows NT4.0 as the platform, forming a Intranet in a hospital. We also discussed the communication problem between the bed-side monitoring station and the central monitoring station in detail and then put forward a new protocol--Hospital Central Monitor Protocol (HCMP) based on TCP/IP to transfer monitoring data. It is easy to achieve tele-monitoring through the current communication subsystem.

Helicobacter pylori alters gastric epithelial cell cycle events and gastrin secretion in Mongolian gerbils

BACKGROUND & AIMS

Human colonization with Helicobacter pylori increases the risk for distal gastric adenocarcinoma, possibly by altering gastric epithelial cell cycle events and/or gastrin secretion. This study aimed to determine whether H. pylori virulence-related characteristics affect apoptosis, proliferation, and gastrin levels in a rodent model of gastric adenocarcinoma.

METHODS

Mongolian gerbils were challenged with H. pylori wild-type or isogenic cagA(-) and vacA(-) mutants, and apoptotic and proliferating cells were identified by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and proliferating cell nuclear antigen immunohistochemistry, respectively. Serum gastrin levels were determined by radioimmunoassay.

RESULTS

Gastric epithelial cell turnover was no different after infection with the wild-type, cagA(-), or vacA(-) strains. H. pylori infection significantly increased antral apoptosis 2-4 weeks after challenge, before apoptotic indices decreased to baseline. In contrast, antral proliferation rates were significantly higher 16-20 weeks after inoculation, but then decreased by 40 weeks. Antral proliferation was significantly related to serum gastrin levels, whereas antral apoptosis was inversely related to acute inflammation and lymphoid follicles.

CONCLUSIONS

In H. pylori-infected gerbils, enhanced antral apoptosis is an early and transient cell cycle event. Epithelial cell proliferation peaks later and is significantly related to increased gastrin levels, suggesting that epithelial cell growth in H. pylori-colonized mucosa may be mediated by gastrin-dependent mechanisms.

Biological relevance of pituitary adenylate cyclase-activating polypeptide (PACAP) in the gastrointestinal tract

Since its initial discovery in 1989, pituitary adenylate cyclase activating peptide (PACAP) has been noted to distribute widely in the brain, the respiratory and the gastrointestinal system. It occurs in two bioactive molecules, PACAP-27 and the C-terminally extended PACAP-38, which evoke activity by binding to three distinct types of high-affinity, G-protein coupled membrane receptors. It is present throughout the entirety of the gut but is rare in certain areas such as the intestinal mucosa and islets of Langerhans. PACAP-induced biological effects are protean and include alterations of motility in the bowel and the gallbladder, stimulation of gastric acid and intestinal secretion, hormone/enzyme release from the exocrine and endocrine pancreas, and the induction as well as inhibition of proliferation in neuroendocrine cells and tumors. Its hepatic activity has to date not been elucidated in detail. One of the interesting features of PACAP is the species and organ dependent variation of its biological effects. Of particular note is its superior potency when compared with other neuropeptides identified in the gut, and the involvement of a number of different second messenger systems upon PACAP receptor activation.

Cell and tumour biology of the gastric enterochromaffin-like cell

The recent recognition of the nature of gastric carcinoids and the elucidation of the biological events associated with enterochromaffin-like cell transformation has provided an opportunity to advance the understanding of this particular type of neuroendocrine tumour. The relationship between hypergastrinaemia present in low acid disease states and the development of gastric carcinoids has led to an appreciation of the role of gastrin as a growth mediator in the evolution of this type of neoplasia. In addition, evidence exists to support a genetic predisposition to this tumour type in individuals with Multiple Endocrine Neoplasia type 1 syndrome, and in an experimental model--the African rodent species, Mastomys. The recent development of an isolated pure enterochromaffin-like cell preparation has facilitated the elucidation of the molecular physiology of the naive enterochromaffin-like cell and, in addition, allowed the evaluation of the cellular events associated with enterochromaffin-like cell transformation from the naive state to the neoplastic phenotype. This synopsis seeks to present information relevant to both the animal model and the human disease state. The aim is to facilitate an appreciation of the regulatory mechanisms of the enterochromaffin-like cell and delineate the changes consequent to the development of the neoplastic phenotype.

[Influence of Helicobacter pylori lipopolysaccharide on the function of enterochromaffin-like cells in vitro]

OBJECTIVE

To investigate the relationship between Helicobacter pylori (Hp) infection and pathophysiology of abnormal gastric acid secretion and mucosal proliferation by studying the effect of Hp lipopolysaccharide (LPS) on the function of enterochromaffin-like (ECL) cells in vitro.

METHODS

Pure isolated ECL cell preparation with a purity of +/- 95% was developed by proteinase digestion, elutriation and density gradient centrifugation with viability of > 95% as determined by trypan blue exclusion. After a short duration of culture basal and stimulated histamine secretion and DNA synthesis of ECL cells were measured by enzyme immunoassay and bromodeoxyuridine (BrdU) uptake, respectively.

RESULTS

Hp LPS stimulated basal and gastrin-stimulated histamine secretion (EC(50)4 x 10(-11) mol/L and EC(50) 10(-10) mol/L respectively). These effects were completely inhibited by somatostatin (10(-10) mol/L) but not by gastrin receptor antagonist L(365 260). Hp LPS did not stimulate basal DNA synthesis but significantly increased gastrin stimulated BrdU uptake with EC(50) of 10(-10) mol/L. Escherichia coil LPS had no significant effect on both histamine secretion and DNA synthesis.

CONCLUSION

Hp stimulates both ECL cell proliferation and secretion in vitro. An interaction between Hp LPS and ECL cells may contribute to the reported abnormalities in acid secretion and gastric pathophysiology noted in Hp infection.

Pituitary adenylate cyclase-activating polypeptide modulates gastric enterochromaffin-like cell proliferation in rats

BACKGROUND & AIMS

Gastric carcinoids (types I and II) involve the transformation of naive enterochromaffin-like (ECL) cells to the neoplastic state and are associated primarily with hypergastrinemia. In this study, we evaluated the effects of two related neuropeptides, pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP), on ECL cell proliferation and characterized the receptor subtype(s) and signal transduction pathways that mediate this effect.

METHODS

Purified rat ECL cells were analyzed in culture for DNA synthesis as measured by 24-hour 5-bromo-2-deoxyuridine (BrdU) uptake. Reverse-transcription polymerase chain reaction (RT-PCR) with gene-specific oligonucleotide primers was performed to characterize the PACAP/VIP receptor subtype(s).

RESULTS

PACAP/VIP neuropeptide-stimulated BrdU uptake was significantly greater (3.4-3.8-fold greater than control) than that at the maximal dose of gastrin (2.2-fold greater than control). PACAP-stimulated ECL cell proliferation (EC50, approximately 3 x 10(-)14 mol/L) was approximately 100-fold more potent than VIP (EC50, approximately 3x 10(-)12 mol/L). The stimulated BrdU uptake by both PACAP and VIP was competitively inhibited by PACAP-receptor antagonist (IC50, 10(-)9 mol/L, 3 x 10(-)9 mol/L, respectively) and VIP-receptor antagonist (IC50, 3 x 10(-)7 mol/L, 5 x 10(-)7 mol/L, respectively). RT-PCR identified the presence of the PACAP-specific but not PACAP/VIP receptor subtypes. The PACAP-stimulated BrdU uptake was inhibited (70%-80%) by inhibitors of adenosine 3',5'-cyclic monophosphate, phosphatidylinositol 3 kinase, and protein tyrosine kinase as well as mitogen-activated protein kinase.

CONCLUSIONS

PACAP/VIP-related peptides are more potent modulators of ECL cell proliferation than gastrin, and their effect is mediated by a PACAP-specific receptor whose activation is transduced by multiple intracellular messenger systems.

Gastrin-regulated expression of p53 in transformed enterochromaffin-like cells in the African rodent mastomys

The tumor suppressor p53 functions at the G1/S-phase checkpoint of the cell cycle to direct cells that have accumulated somatic mutations toward apoptosis and away from mitosis. The p53 gene is commonly mutated in human cancers, but the molecular mechanisms regulating this event are not clear. The African rodent mastomys exhibits a genetic predisposition to develop gastric carcinoids derived from enterochromaffin-like (ECL) cells. The ECL cell transformation can be accelerated by acid inhibition-induced hypergastrinemia. This study evaluates the alteration of p53 during the rapid ECL cell transformation. Hypergastrinemia was generated by the irreversible histamine-2 receptor antagonist loxtidine for 8 weeks (hyperplasia) and 16 weeks (neoplasia). p53 expression was evaluated in fundic mucosa from different stages of transformation by Western blot analysis and immunohistochemistry using monoclonal antibodies against wild-type p53. RT-PCR and molecular sequence analysis of p53 were undertaken with mRNA isolated from purified ECL cells. Overproduction of the wild type of p53 was evident in ECL cells during hypergastrinemia, and the molecular characteristics of p53 were determined in naive and transformed ECL cells. p53 was mutated at the C-terminus in ECLoma induced by hypergastrinemia. Therefore, p53 is altered from overproduction to mutation during the development of hypergastrinemia-induced ECLoma and it may therefore play a role in the cell transformation.

A polyamine pathway-mediated mitogenic mechanism in enterochromaffin-like cells of Mastomys

We have previously demonstrated that in Mastomys species proliferation of gastric enterochromaffin-like (ECL) cells is predominantly regulated by gastrin and by transforming growth factor-alpha (TGF-alpha) in the naive and neoplastic state, respectively. In this study we examined whether these intracellular mitogenic responses are mediated by polyamines and ornithine decarboxylase (ODC), the rate-limiting enzyme for polyamine biosynthesis. An ECL cell preparation of high purity was used to measure the effect of the polyamine derivatives putrescine, spermidine, and spermine on DNA synthesis by bromodeoxyuridine uptake. Both putrescine and spermidine augmented gastrin-stimulated, but not basal, DNA synthesis in naive cells. This proliferative response correlated with an increase in ODC activity that was partially inhibited (20%) by difluoromethylornithine (DFMO), an inhibitor of ODC (IC50, 30 pM). In contrast, all polyamines increased both basal and TGF-alpha-stimulated DNA synthesis as well as ODC activity in tumor ECL cells. DFMO completely inhibited the proliferative response of TGF-alpha (IC50, 3 pM). Thus polyamine biosynthesis is involved in proliferation of ECL cells and in particular the mitogenesis of tumor cells, suggesting a role for this pathway in the regulation of ECL cell transformation.

Telenzepine-sensitive muscarinic receptors on rat pancreatic acinar cells

To identify the muscarinic subtype present on the rat pancreatic acinar cell, we examined the effects of different muscarinic receptor antagonists on amylase secretion and proteolytic zymogen processing in isolated rat pancreatic acini. Maximal zymogen processing required a concentration of carbachol 10- to 100-fold greater (10(-3) M) than that required for maximal amylase secretion (10(-5) M). Although both secretion and conversion were inhibited by the M3 antagonist 4-diphenylacetoxy-N-methyl-piperidine (4-DAMP) (50% inhibition approximately 6 x 10(-7) M and 1 x 10(-8) M, respectively), the most potent inhibitor was the M1 antagonist telenzepine (50% inhibition approximately 5 x 10(-10) M and 1 x 10(-11) M, respectively). Pirenzepine, another M1 antagonist, and the M2 antagonist methoctramine did not reduce amylase secretion or zymogen processing in concentrations up to 1 x 10(-5) M. Analysis of acinar cell muscarinic receptor by PCR revealed expression of both m1 and m3 subtypes. The pancreatic acinar cell has a distinct pattern of muscarinic antagonist sensitivity (telenzepine >> 4-DAMP > pirenzepine) with respect to both amylase secretion and zymogen conversion.

Helicobacter pylori lipopolysaccharide stimulates histamine release and DNA synthesis in rat enterochromaffin-like cells

BACKGROUND & AIMS

Helicobacter pylori alterations in gastric acid output and mucosal proliferation may involve the enterochromaffin-like (ECL) cell. To test whether H. pylori affects ECL cell histamine secretion and proliferation, the effect of lipopolysaccharide (LPS) on ECL cell function in vitro was investigated.

METHODS

Using a rat ECL cell preparation of high purity (+/-95%), basal and stimulated histamine secretion and DNA synthesis were measured by enzyme immunoassay and bromodeoxyuridine (BrdU) uptake, respectively.

RESULTS

Escherichia coli LPS (10(-12) to 10(-6) mol/L) had no effect on basal and stimulated histamine secretion at concentrations of > 10(-6) mol/L. H. pylori LPS stimulated basal and gastrin-stimulated histamine secretion. These effects were completely inhibited by somatostatin (10(-10) mol/L) but not by the gastrin receptor antagonist L365,260 at 10(-6) mol/L. E. coli LPS had a weak stimulatory effect on ECL cell BrdU uptake at 10(-6) mol/L but had no effect on gastrin-stimulated BrdU uptake. H. pylori LPS did not stimulate basal synthesis but significantly increased (1.5-fold) gastrin-stimulated BrdU uptake.

CONCLUSIONS

H. pylori influences both ECL cell proliferation and secretion in vitro. An interaction between H. pylori LPS and ECL cells may contribute to the reported abnormalities in acid secretion and gastric pathobiology noted in H. pylori infections.

Gastrin receptor expression and function during rapid transformation of the enterochromaffin-like cells in an African rodent

The enterochromaffin-like cell (ECL) cells of the stomach are principally regulated by gastrin via a gastrin/CCK(B) receptor (G[R]) which modulates both histamine secretion and cell proliferation. In the African rodent (mastomys) hypergastrinemia generated by the histamine-2 receptor antagonist (loxtidine) results in ECL cell hyperplasia and neoplasia at 8 and 16 weeks respectively. The expression, structure and function of the G(R) during transformation is however unknown. We utilized a pure (approximately 90%) preparation of ECL cells to evaluate alterations in the G(R) utilizing immunocytochemistry, Western blot analysis, reverse transcription polymerase chain reaction (RT-PCR), 5-bromo-2-deoxyuridine uptake and phosphorylation site analysis. Although the expression of ECL cell G(R) was upregulated at both mRNA (PT-PCR) and protein (Western analysis) level, its affinity to gastrin was decreased in the hyperplastic phase and lost during transformation. The coding sequence of the G(R) of mastomys tumor ECL cells was identical to that of normal ECL cells, parietal cells and the brain. However, the mRNA sequence of the third introcytoplasmic loop of the G(R) was significantly different to other species. In addition, the G(R) exhibited phosphorylation site on serine residue(s). We have thus noted a direct correlation between hypergastrinemia and G(R) alteration and function during ECL cell transformation. It is possible that the unique mastomys gastrin receptor mediated ECL cell transformation involves the novel phosphorylation sites and a divergence in the introcytoplasmic domain.

Genetic differentiation among three populations of Anopheles minimus of Guangxi and Yunnan Provinces in the People's Republic of China

Electrophoretic studies were carried out on isozymes of 3 populations of Anopheles minimus collected from Guangxi and Yunnan Provinces of the People's Republic of China in 1993. Eight proteins were analyzed by 5% polyacrylamide gel electrophoresis. The most variable population, 'Yunnan-Field' (Y-F), was highly polymorphic at 14 of 20 loci (P = 0.700) with an average heterozygosity H of 0.340. P values of 0.500 and 0.700, and H values of 0.220 and 0.210 were obtained for each from 'Guangxi-Lab' (GX-L) and 'Yunnan-Lab' (Y-L), respectively, Nei's genetic distances (D) between Y-L and GX-L, Y-F and GX-L, and Y-F and Y-L were 0.1131, 0.1946 and 0.1069, respectively. These results suggest that GX-L is distant from the 2 other populations, Y-L and Y-F, and that this genetic differentiation between the 2 populations of Yunnan and Guangxi Provinces corresponds to the forms A and B, which were morphologically classified by Xu et al (unpublished).

A 40-year analysis of 265 gastric carcinoids

OBJECTIVES

Gastric carcinoid tumors were previously regarded as rare, benign neoplasms. Few data are available on the epidemiology of this lesion.

METHODS

We have analyzed the End Results Group (1950-1969), the Third National Cancer Survey (1969-1971) and the Surveillance, Epidemiology, and End Results (SEER, 1973-1991) databases of the National Cancer Institute. The three files consist of 8305 carcinoid cases collectively, including 265 gastric carcinoids.

RESULTS

The percentage of gastric carcinoids among all gastric malignancies has increased from 0.3% to 0.54%. The black:white ratio declined from 0.36 to 0.17 as well as the male:female ratio from 0.9 to 0.57. The age-adjusted incidence rates have increased in white females but are much higher for the black population. Gastric carcinoids are associated with other malignant neoplasms in 7.8% of cases. The 5-yr survival rates for localized lesions, with regional and with distant metastases, were 48.6%, 39.9%, and 10%, respectively.

CONCLUSIONS

Gastric carcinoids have increased in incidence over the last 20 yr. This may represent either improved diagnostic techniques, increased awareness, or a real change in incidence. Poor 5-yr survival rates indicate that gastric carcinoid tumors exhibit an aggressive biological behavior.

Study of simplified measures for malaria surveillance in the late consolidation phase in China

This paper presents the results of a study on simplified surveillance methods conducted in 23 pilot counties in 11 provinces and municipalities in China where reside 15 million people and malaria control has been in the late consolidation phase. Two simplified surveillance Schemes (A and B) taking treatment of clinical cases as the main measure were implemented in 1992-1994. The rate of annual blood examination for case detection was 1.0% in pilot Scheme A, while in areas of scheme B it was 0.3%. The implementation of both Scheme A and Scheme B, simplified or without treatment of infection foci and management of mobile populations, acquired satisfactory effects against malaria. Consequently, malaria incidence was declining steadily, only a few indigenous and introduced cases were detected. The parasite rate in residents and the IFA positive rate in children were very low. The results of pilot studies and cost-effectiveness analysis indicated that Scheme B is effective, rational and economic, and can be implemented to replace the routine surveillance measures in areas where malaria has been at the late consolidation phase in China.