Active infection with Helicobacter pylori in healthy couples

The mode of spread of Helicobacter pylori infection is subject to ongoing debate. Recent studies among patients with gastrointestinal disorders suggest a potential role of conjugal transmission. In this study, the clustering of H. pylori infection was assessed among 110 employees of a health insurance company and their partners. Active infection with H. pylori was measured by the 13C-urea breath test. Information on potential confounders was collected by a standardized questionnaire. Overall, 16 employees (14.5%) and 24 partners (21.8%) were infected. While only 7% (6/86) of employees with an uninfected partner were infected, this applied to 42% (10/24) of employees with an infected partner. A very strong relation between partners' infection status persisted after control for age and other potential confounders (adjusted odds ratio, 7.0; 95% confidence interval, 1.8-26.7). Furthermore, the risk of infection increased with the number of years lived with an infected partner. These results support the hypothesis of a major role of spouse-to-spouse transmission of H. pylori infection.

NF-kappaB/Rel activation in cerulein pancreatitis

BACKGROUND & AIMS

Recent evidence suggests that a number of rapid signaling cascades are initiated during secretagogue-induced pancreatitis. However, little is known about the nuclear events. The aim of this study was to explore activation of the transcription factor NF-kappaB/Rel after supramaximal stimulation with the cholecystokinin analogue cerulein in the pancreas.

METHODS & RESULTS

Nuclear appearance of NF-kappaB/Rel-binding activity was detectable 15 minutes after cerulein injection. The DNA-binding activity consisted of NF-kappaB1 p50, NF-kappaB2 p52, and RelA p65 as judged by supershift assays and Western blot analysis. The onset and termination of NF-kappaB/Rel activation correlated with the degradation and reappearance of IkappaBalpha. Cerulein in supramaximal but not in physiological doses activated NF-kappaB/Rel in vitro. After blocking of NF-kappaB/Rel activation with pyrrolidine dithiocarbamate, the degree of morphological alterations was more pronounced than in controls, serum amylase and lactate dehydrogenase levels were significantly increased, and messenger RNA levels of pancreatitis-associated protein were more strongly induced, reflecting a more severe degree of pancreatitis. Similar results were obtained when N-acetyl-L-cysteine was used as an inhibitor of NF-kappaB activation.

CONCLUSIONS

These data show that NF-kappaB/Rel is rapidly activated during cerulein pancreatitis. This activation may induce a self-defending genetic program before the onset of cellular injury, which might prevent higher degrees of damage of pancreatic acinar cells after secretagogue hyperstimulation.

Helicobacter pylori among preschool children and their parents: evidence of parent-child transmission

This study assessed the role of parental infection status in the transmission of Helicobacter pylori infection in a large population-based sample of preschool-aged children. The subjects, who lived in Ulm, Germany, and in two nearby communities, were screened for school fitness between January and July 1997. Their H. pylori infection status was determined by 13C-urea breath test. Of 1522 eligible children, 1221 (80.2%) participated in the study. Crude prevalence of H. pylori infection in children was 11.3% (95% confidence interval [CI], 9.5-13.3) and 36.4% in their parents (95% CI, 33.5-39.4). The crude odds ratio (OR) for H. pylori infection of children whose mothers were infected was 16.5 (95% CI, 8.9-30.8) and 7.9 after adjustment for potential confounders (95% CI, 4.0-15.7). The crude OR if the child's father was infected was 7.8 (95% CI, 2. 5-24.2) and 3.8 after adjustment for potential confounders (except maternal infection) (95% CI, 0.8-19.1). The results suggest that infected parents, especially infected mothers, may have a key role in transmission of H. pylori within families.

Expression and differential regulation of connective tissue growth factor in pancreatic cancer cells

CTGF is an immediate early growth responsive gene that has been shown to be a downstream mediator of TGFbeta actions in fibroblasts and vascular endothelial cells. In the present study hCTGF was isolated as immediate early target gene of EGF/TGFalpha in human pancreatic cancer cells by suppression hybridization. CTGF transcripts were found in 13/15 pancreatic cancer cell lines incubated with 10% serum. In 3/7 pancreatic cancer cell lines EGF/TGFalpha induced a significant rise of CTGF transcript levels peaking 1-2 h after the start of treatment. TGFbeta increased CTGF transcript levels in 2/7 pancreatic cancer cell lines after 4 h of treatment and this elevation was sustained after 24 h. Only treatment with TGFbeta was accompanied by a parallel induction of collagen type I transcription. 15/19 human pancreatic cancer tissues were shown to overexpress high levels of CTGF transcripts. CTGF transcript levels in pancreatic cancer tissues and nude mouse xenograft tumors showed a good correlation to the degree of fibrosis. In situ hybridization and the nude mouse experiments revealed that in pancreatic cancer tissues, fibroblasts are the predominant site of CTGF transcription, whereas the tumor cells appear to contribute to a lesser extent. We conclude that CTGF may be of paramount importance for the development of the characteristic desmoplastic reaction in pancreatic cancer tissues.

Cholecystokinin-induced redistribution of paxillin in rat pancreatic acinar cells

Cholecystokinin (CCK) dose-dependently stimulates enzyme secretion or loss of cell integrity in the exocrine pancreas. Signaling mechanims include tyrosine phosphorylation of p125(FAK) and paxillin. Here, we examine their potential function. Maximum phosphorylation of both proteins was observed after stimulation of freshly isolated rat pancreatic acini with 10 nM CCK, a concentration known to initiate breakdown of the terminal actin web and cell damage. Under these conditions, CCK initiated transient redistribution of paxillin from the apical cytosol to the apical and lateral plasma membrane within 2 min, where it colocalized with the terminal actin web. Relocation of paxillin was confirmed in subcellular fractions by western blotting and coincided with maximum phosphorylation of membrane-bound p125(FAK) and paxillin. Subsequently, paxillin was redistributed to the basolateral cytosol and was degraded. p125(FAK) remained membrane-bound. We conclude that phosphorylation and redistribution of paxillin and phosphorylation of p125(FAK) may participate in the CCK-induced disassembly of acinar cell actin.

[Pathological bone density in chronic inflammatory bowel diseases--prevalence and risk factors]

INTRODUCTION

Osteopenia and osteoporosis are frequent but often underestimated complications in inflammatory bowel disease. In patients with IBD, several factors could contribute to osteopenia, but the pathogenetic mechanisms are still not completely understood. We carried out a prospective study to evaluate the prevalence and possible etiologic factors for osteopenia and subsequent osteoporosis in IBD-patients.

METHODS

140 patients with inflammatory bowel disease (Crohn's disease n = 125, ulcerative colitis n = 15) underwent clinical and spine radiological assessments. Lumbar bone mineral densities were measured by dual energy X-ray absorptiometry (DXA). Markers of bone formation and resorption and vitamin D were assessed in n = 95 patients. Patients were asked about medication, previous or actual intestinal stenosis, smoking and intestinal resection. A lactose-H2-breath test was undertaken if lactose intolerance was clinically suspected.

RESULTS

Compared to age- and sex-matched healthy controls (Z-score), the prevalence of osteopenia (Z < -1) was 62%, while osteoporosis (Z < -2) occurred in 38%. The mean bone density of IBD-patients was osteopenic with no significant differences between Crohn's disease (Z = -1.24) and ulcerative colitis (Z = -1.25). Osteoporotic fractures were seen in three patients (2.1%). Crohn's disease patients with osteoporosis showed a significant lower body mass index (BMI) than patients with normal bone density. 52.9% of patients with manifest osteoporosis underwent systemic steroid treatment in the preceding year, but only 34% of those with normal bone density. Except hemoglobin, none of the biochemical markers showed a significant difference between osteoporosis, osteopenia and patients with normal bone density.

CONCLUSION

The results show a high prevalence of osteopenia and osteoporosis in IBD. Since osteoporosis is often associated with low body mass index, multiple intestinal resections and previous systemic steroid treatment, we suggest a bone densitometry in these patients. Since etiology of osteoporosis in IBD is multifactorious and not completely understood, there is still no standard treatment. The effect of osteoanabolic and antiresorptive agents must be evaluated in further studies.

Fibroblasts stimulate acinar cell proliferation through IGF-I during regeneration from acute pancreatitis

Pancreatic regeneration after caerulein-induced pancreatitis is characterized by transient fibroblast proliferation followed by replication of acinar cells. The mechanisms that coordinate regeneration are incompletely understood. In this study, we examine the role of insulin-like growth factor I (IGF-I). Acute edematous pancreatitis was induced in rats by 12 h caerulein infusion. Pancreatic IGF-I mRNA levels increased over 50-fold during regeneration, reaching a maximum at day 2. Immunohistochemically, IGF-I was localized to fibroblasts within the areas of interstitial tissue. IGF-I mRNA was demonstrated in primary cultures of pancreatic fibroblasts but not in cultured pancreatic acinar cells. However, with the use of Western blotting acinar cells did express IGF-I receptors. IGF-I stimulated 5-bromo-2'-deoxyuridine uptake and increased numbers of acinar cells in a dose-dependent manner. Stimulation was half maximal at 1.1 nM and completely inhibited by an IGF-I antagonist and by IGF binding protein-3 (IGFBP-3). Possible paracrine regulation was confirmed by stimulation of acinar cell proliferation with fibroblast-conditioned medium, which was partially inhibited by IGF-I antagonist or by IGFBP-3. We conclude that acinar cell proliferation during late regeneration from pancreatitis is mediated at least in part by paracrine release of IGF-I from fibroblasts.

Hepatocyte growth factor and fibroblast growth factor 2 are overexpressed after cerulein-induced acute pancreatitis

The regenerative process after acute inflammation of the pancreas is characterized by cell proliferation as well as synthesis and transient deposition of extracellular matrix. Although the regulation of these processes is still unknown, there is growing evidence that the coordinated activity of various growth factors plays an important role in regeneration. Cerulein-induced pancreatitis in the rat was used to analyze whether growth factors and their receptor concentrations are changed in the acute pancreatitis. Messenger RNA hybridization revealed an individual expression pattern for each analyzed growth factor. The mRNA levels of platelet-derived growth factor B (PDGF B), epidermal growth factor (EGF), and insulin-like growth factor 2 (IGF-2) were not altered, whereas fibroblast growth factor-1 (FGF-1) and 2, IGF-1, transforming growth factor-alpha (TGFalpha), and hepatocyte growth factor (HGF) showed markedly increased concentrations with different expression maxima and duration compared with mRNA levels in healthy pancreata. The FGF-2 and IGF-1 expressions were increased between 1 and 3 days after induction of pancreatitis with maxima at day 2. HGF and FGF-1 mRNAs were upregulated between days 3 and 5. In contrast, TGFalpha exhibited the most prolonged overexpression. In the corresponding receptors, only c-met, the HGF-binding protein, showed higher mRNA and protein levels, whereas the expression of the other receptors did not change. Furthermore, in cultured pancreatic epithelial cells, HGF stimulated the expression of its own receptor in an autocrine manner. These results point out that the highly coordinated process of regeneration after pancreatitis may be influenced by a sequential induction and expression of peptide growth factors and their receptors.

Bak expression and cell death occur in peritumorous tissue but not in pancreatic cancer cells

Bak is a pro-apoptotic member of the Bcl-2 family whose genes are involved in regulation of programmed cell death. Using in situ hybridization, immunohistochemistry, and Northern blot analysis, we studied the expression of Bak in specimens from 12 normal pancreata and 26 primary pancreatic cancers, and correlated the findings with the clinical and histopathologic data of the patients. By comparison with normal pancreas, Northern blot analysis demonstrated a 2.5-fold increase of Bak messenger RNA expression in the tumor samples (P <0. 001). Elevated levels were found in 15 of the 26 pancreatic cancer tissue specimens. In these samples Bak expression was increased 4.3 fold (P <0.001). No association was detected between Bak expression and tumor stage. In situ hybridization and immunohistochemistry revealed that the tumor cells themselves and the stroma cells expressed only low levels of Bak. In contrast, in regions adjacent to the tumor, which showed chronic inflammation, there was always high expression in the acinar and inflammatory cells, explaining the increased Bak levels found in the tumor samples by means of Northern blot analysis. In the normal pancreas the expression of Bak was generally moderate in the acinar cells and low in the ductal and islet cells. In situ analysis using the terminal deoxynucleotidyl transferase method further showed that there was extensive cell death in the peritumorous areas with chronic inflammation. Taken together, these results suggest that in pancreatic cancer Bak expression and programmed cell death are present in cells that are localized in regions of chronic inflammation surrounding the pancreatic cancer cells but not in the tumor cells themselves, a situation that may facilitate tumor growth and spread.

Moderate activation of the apoptosis inhibitor bcl-xL worsens the prognosis in pancreatic cancer

OBJECTIVE

To analyze the expression of the antiapoptotic gene bcl-xL in human pancreatic cancer and to correlate the results with clinical patient parameters.

SUMMARY BACKGROUND DATA

Bcl-xL belongs to the bcl-2-related gene family and acts as a broad antiapoptotic factor to extend both normal and tumor cell survival. Recent findings indicate that tumor cell death induced by chemotherapy and radiotherapy is mediated by the activation of apoptosis. The fact that pancreatic cancer has an extremely malignant potential and that it is resistant to most anticancer treatment modalities suggests that mechanisms are activated that increase the viability of pancreatic cancer cells.

METHODS

Seventy-four pancreatic cancer tissue samples were obtained from 32 female and 42 male patients undergoing surgery for exocrine pancreatic cancer. Normal human pancreatic tissue samples were available from 11 organ donors and 4 patients without pancreatic disease. The levels of bcl-xL mRNA expression were analyzed by Northern blot analysis. The exact site of bcl-xL mRNA transcription was determined by nonradioactive in situ hybridization. In addition, immunohistochemistry using specific polyclonal antibodies was used to localize the protein.

RESULTS

Northern blot analysis indicated that, in comparison with the normal pancreas, bcl-xL mRNA was markedly overexpressed in 54% of the pancreatic cancer samples. Densitometric analysis revealed that pancreatic adenocarcinomas exhibited a mean 3.4-fold increase (p < 0.01) in bcl-xL mRNA levels in comparison with normal controls. With in situ hybridization, bcl-xL mRNA was found to be highly expressed in the cancer cells of tumor samples that exhibited increased mRNA expression by Northern blot analysis. Immunohistochemical analysis revealed bcl-x immunostaining in 88% of the cancer samples. Correlation of the molecular data with clinical patient parameters revealed that patients whose tumors exhibited no, faint, or weak bcl-xL expression lived significantly longer after tumor resection (median 12 months) than patients whose tumors exhibited moderate bcl-xL mRNA expression (median 5 months) (p < 0.05). However, 5 patients whose tumors exhibited intense bcl-xL mRNA expression tended to live longer (median 14 months).

CONCLUSION

Enhanced expression of the antiapoptotic gene bcl-xL in pancreatic cancer and its association with shorter patient survival suggests that this factor may enhance the viability of pancreatic cancer cells in vivo. Inhibition of apoptotic pathways might be one of the reasons why pancreatic cancer shows only limited sensitivity to anticancer treatment.

Relationship between Helicobacter pylori infection, histological gastritis, and functional dyspepsia

BACKGROUND/AIMS

It is still controversial as to whether or not Helicobacter pylori (H. pylori) infection, histological gastritis, and functional dyspepsia (FD) are intercorrelated. We prospectively evaluated patients with functional dyspepsia in an attempt to clarify this issue.

METHODOLOGY

Eighty-eight consecutive patients with functional dyspepsia (age range: 18-84 years) who did not show disease(s) other than gastritis were investigated. In a questionnaire they were asked to report the presence or absence of 8 upper gastrointestinal (GI) symptoms and to score them from 0 (absence) to 3 (severe), whereupon a sum score was calculated. Forty age-matched subjects with a sum score of <3 served as controls. Biopsy specimens for histology, bacterial culture, and rapid urease test were taken. A C13-urease breath test was also performed in 122 subjects.

RESULTS

H. pylori infection was present in 43% of patients with functional dyspepsia and 35% of control subjects (not significant (n.s.)). None of the symptoms were correlated with H. pylori infection. The median symptom sum score was 8.5 in H. pylori-positive and 9.5 in H. pylori-negative patients with functional dyspepsia (n.s.). Histological gastritis was strongly associated with H. pylori infection but was not correlated with any of the symptoms.

CONCLUSIONS

In a prospective population of patients with functional dyspepsia, H. pylori infection or gastritis are not associated with specific or severe symptoms. Our data imply that H. pylori gastritis is not an important condition in the pathogenesis of dyspeptic complaints.

Malignant transformation of duct-like cells originating from acini in transforming growth factor transgenic mice

BACKGROUND & AIMS

In transgenic mice overexpressing transforming growth factor (TGF)-alpha in the exocrine pancreas, progressive pancreatic fibrosis and a transdifferentiation of acinar cells to duct-like cells occurs. The present study was undertaken to analyze this transdifferentiation process.

METHODS

Pancreatic specimens were characterized using light microscopy and immunohistochemistry. Expression of the epidermal growth factor receptor (EGFR) and TGF-alpha was evaluated with slot blot and Western analysis. To identify other generic events, K-ras mutations were screened with an enriched polymerase chain reaction approach and p53 expression was detected with immunohistochemistry.

RESULTS

Morphological examination revealed an aggregation of interlobular fibroblasts and a decrease in acinar cell height starting at day 14 after birth. In older animals, these acinar cells change to duct-like cells, which form tubular structures and express ductal markers. Evidence for dysplastic changes was found in 12 of 21 TGF-alpha transgenic mice older than 1 year. We also observed four malignant pancreatic tumors, which were multicentric and originated from dysplastic tubular complexes. They displayed a mixed cystic-papillary phenotype strongly positive for carbonic anhydrase activity. EGFR expression progressively increased in the transition from acinar to duct-like and transformed cells. Activating K-ras mutations could not be detected; however, tubular complexes and tumors displayed increased immunoreactivity for nuclear p53.

CONCLUSIONS

These data suggest an involvement of the TGF-alpha/EGFR pathway in conjunction with other yet unknown events in pancreatic tumor development. Furthermore, these observations are in favor of an acinar-ductal carcinoma sequence. Thus, these transgenic animals will be useful to define genetic alterations associated with a transition from acinar cells to a neoplastic ductal phenotype.

Pets are not a risk factor for Helicobacter pylori infection in young children: results of a population-based study in Southern Germany

BACKGROUND

Helicobacter pylori may have multiple routes of transmission. It is unclear, however, whether the agent is also zoonotic and therefore transmitted from an animal reservoir.

AIMS

The aim of this population-based study was to assess the relationship of exposure to pets and H. pylori infection among children in a population-based sample in Ulm, a city in the South of Germany.

SUBJECTS AND METHODS

All children of German nationality who were to attend first grade in the school year 1996/1997 were included in the study. The 13C-urea breath test was used to determine active infection status. In addition the parents filled out a questionnaire to provide information about pets in the household as well as living conditions and socioeconomic factors of the family.

RESULTS

Of 927 eligible preschool children 685 (74%) participated in the study. Prevalence of infection was 6.3%. Infection with H. pylori was not positively associated with contact with pets in general (p = 0.720) or to a specific kind of animal in bivariate and multivariable analyses as evaluated by means of logistic regression.

CONCLUSIONS

These results suggest that pets in the household are not a risk factor for H. pylori infection among children in this population.

The splice-pattern of CD44 is altered in chronic pancreatitis exhibiting dysplastic changes

Recent studies have shown that several splice variants of CD44, might be involved in tumor progression. Since chronic pancreatitis is suggested to be a risk factor for pancreatic cancer we investigated the splice pattern of CD44 in chronic pancreatitis to elucidate the role of CD44 in pancreas tumorigenesis. The expression of CD44-isoforms was examined in 40 specimens of chronic pancreatitis and 12 specimens of normal pancreas by immunohistochemistry, Westernblotting and exon specific RT-PCR. Pancreatic cancer tissue from two patients who developed pancreatic cancer 2 and 3 years following surgery for chronic pancreatitis were analyzed. Strong expression of CD44s was found in all cells, whereas the expression of CD44v6 was restricted to ductal cells. Westernblotting revealed an overexpression of CD44v6 in chronic pancreatitis as compared to normal pancreas. Exon specific analysis revealed an altered splice pattern of CD44, similar to that in pancreatic cancer, in 12.5% of the chronic pancreatitis specimens. Both patients who developed pancreatic cancer after chronic pancreatitis exhibited this altered splice pattern in both, chronic pancreatitis and pancreatic cancer. These results suggest that variant forms of CD44-mRNA might be expressed in early dysplastic alterations in chronic pancreatitis.

Dyspepsia in relation to Helicobacter pylori infection and psychosocial work stress in white collar employees

OBJECTIVE

We undertook an investigation of the relationship between psychosocial work stress and Helicobacter pylori (H. pylori) infection with dyspepsia.

METHODS

We conducted a cross-sectional study among 189 employees of a health insurance company in the city of Ulm, Germany.

RESULTS

A clear association between work-related psychosocial factors and the occurrence of dyspeptic symptoms during the past 3 months was evident. Persons who were considered to have a critical style of coping with work demands suffered more often from dyspeptic symptoms. Current infection with H. pylori was not associated with prevalence of dyspeptic symptoms. These results were also confirmed by adjustment for age, gender, smoking status, education, and use of antiinflammatory drugs within the past 3 months, by means of multivariate analysis. The odds ratio (OR) for having a dyspepsia symptom score in the upper tertile versus the 1st or 2nd was 3.22 (95% confidence interval [CI], 1.56-6.65), given that the employee was considered to have a critical style of coping with work demands. The OR for having a dyspepsia symptom score in the upper tertile given H. pylori infection was 1.23 (95% CI, 0.44-3.46), indicating no association of current H. pylori infection with dyspeptic symptoms.

CONCLUSIONS

A critical style of coping with work demands may be an important determinant for dyspepsia-like symptoms. Therefore, in the absence of an underlying disease, specific intervention programs should be targeted at the behavior of the affected individual (e.g., stress-reduction programs) rather than on the treatment of specific symptoms or infection with H. pylori.

bax, but not bcl-2, influences the prognosis of human pancreatic cancer

BACKGROUND

bcl-2 and bax belong to the bcl-2-related gene family, which marks a new class of genes that influence apoptosis. The bcl-2 oncogene acts as a broad antiapoptotic factor and extends both normal and tumour cell survival. In contrast, the bax gene is a promoter of apoptosis.

AIMS

To analyse the expression of bcl-2 and bax in pancreatic cancer and correlate the results with clinical parameters.

PATIENTS

Pancreatic cancer tissue samples were obtained from 28 female and 32 male patients (median age 63, range 43-79 years) having surgery for pancreatic cancer. Normal pancreatic tissues obtained from 18 previously healthy organ donors served as controls.

METHODS

The levels of bcl-2 and bax mRNA expression were analysed by northern blot and the exact site of mRNA transcription was determined by in situ hybridisation. The presence of the corresponding proteins was determined by immunohistochemistry.

RESULTS

Northern blot analysis indicated that, in comparison with the normal pancreas, bcl-2 mRNA was overexpressed in 30% and bax mRNA in 61% of the pancreatic cancer samples. Concomitant overexpression of bcl-2 and bax was present in 26% of the cancer samples. Pancreatic adenocarcinomas exhibited 3.7-fold and 5.4-fold increases (p < 0.001) in bcl-2 and bax mRNA levels respectively. In situ hybridisation showed that both bcl-2 and bax mRNA were expressed in the cancer cells. Immunohistochemical analysis showed positive Bcl-2 and Bax immunostaining in 28 and 83% of the cancer samples respectively. In multivariate analysis (Cox regression model), bax expression was found to be a strong indicator of survival (p < 0.001). Patients whose tumours exhibited Bax immunostaining lived significantly longer (12 months) than those whose tumours were Bax negative (five months) (p < 0.039). In contrast, no relation was found between Bcl-2 and survival time.

CONCLUSIONS

The data indicate that genes that are involved in the regulation of apoptosis are upregulated in human pancreatic cancer cells. Prolonged survival times in patients in whom apoptosis promoting factors are upregulated indicate that apoptotic pathways are of biological significance in pancreatic cancer.

Parental smoking and infection with Helicobacter pylori among preschool children in southern Germany

Exposure to parental smoking is known to increase children's susceptibility to a variety of infections. We investigated the relation of parental smoking to infection with Helicobacter pylori in a population-based study among preschool children who were screened for school fitness in the city of Ulm, Germany, in 1996. Current infection with H. pylori was measured by a 13C-labeled urea breath test. Information on factors potentially related to H. pylori infection, including parental smoking in the household, was obtained from children's parents through a self-administered standardized questionnaire. Among 1,201 eligible children, 945 participated in the study (response rate = 79%). Overall prevalence of active infection was 13.7%. After adjustment for confounding factors, we found a strong positive relation between smoking by the father in the household and H. pylori infection (odds ratio = 3.7; 95% confidence interval = 2.3-6.1). By contrast, there was a strong negative relation between smoking by the mother and H. pylori infection (odds ratio = 0.4; 95% confidence interval = 0.2-0.8) that was most pronounced among children who had been breastfed. These striking patterns cannot be explained by current knowledge.

Src stimulates insulin-like growth factor I (IGF-I)-dependent cell proliferation by increasing IGF-I receptor number in human pancreatic carcinoma cells

We examined the potential function of Src in human pancreatic carcinoma. Overexpression of kinase-activated SrcY527F resulted in a significant increase of insulin-like growth factor I (IGF-I)-dependent cell proliferation in the cell line PANC-1. Western blotting and competition binding studies demonstrated 2.3 +/- 0.2-fold increase in IGF-I receptor expression and 2.8 +/- 0.4-fold increase in IGF-I-specific binding sites/cell. SrcY527F transfection alone did not change receptor affinity or basal receptor tyrosine phosphorylation, whereas IGF-I-stimulated receptor phosphorylation was increased by 2.1 +/- 0.5-fold. IGF-I mRNA expression and protein secretion did not change to exclude autocrine activation. We conclude that Src stimulates IGF-I-dependent proliferation of PANC-1 cells by increasing the number of IGF-I receptors/cell.

Identification, culture, and characterization of pancreatic stellate cells in rats and humans

BACKGROUND & AIMS

Until now, the basic matrix-producing cell type responsible for pancreas fibrosis has not been identified. In this report, retinoid-containing pancreatic stellate cells (PSCs) in rat and human pancreas are described, and morphological and biochemical similarities to hepatic stellate cells are shown.

METHODS

Electron and immunofluorescence microscopy (collagen types I and III, fibronectin, laminin, alpha-actin, and desmin) was performed using pancreatic tissue and cultured PSCs. Extracellular matrix synthesis was shown using quantitative immunoassay and Northern blot analysis.

RESULTS

PSCs are located in interlobular areas and in interacinar regions. Early primary cultured PSCs contain retinol and fatty acid retinyl-esters. Addition of retinol to passaged cells resulted in retinol uptake and esterification. During primary culture, the cells changed from a quiescent fat-storing phenotype to a highly synthetic myofibroblast-like cell expressing iso-alpha-smooth muscle actin (>90%) and desmin (20%-40%) and showing strong positive staining with antibodies to collagen types I and III, fibronectin, and laminin. As determined on protein and messenger RNA level, serum growth factors stimulated the synthesis of collagen type I and fibronectin.

CONCLUSIONS

The identification of PSCs, particularly in fibrotic areas, and the similarities of these cells to hepatic stellate cells suggest that PSCs participate in the development of pancreas fibrosis.