In vitro toxicity of surfactants in U937 cells: cell membrane integrity and mitochondrial function

Surface-active agents are components of many drugs and cosmetics. In order to examine their cytotoxic and membrane-toxic potential, various surfactants were examined in U937 cells using the tetrazolium reduction assay EZ4U, a modified XTT test, and the arachidonic acid release test (AART). EZ4U measures the ability of living cells to reduce a colorless tetrazolium salt to an orange water-soluble formazan derivative by mitochondrial dehydrogenases. [3H]arachidonic acid ([3H]AA) is rapidly incorporated into cell membrane phospholipids. Due to membrane disintegration or enzymatic catalysis, it is released into the cell culture medium and can be measured by scintillation technique. The results after 24-hour-exposure are as follow (CC50 microg/ml; RC50 microg/ml): benzalkonium chloride (0.6), Cremophor A25 (1.4; 5.9), sodium cetearyl sulfate (1.6; 19.9), Brij78 (1.6; 7.7), TEGO betaine E (3.0; 19.3), TEGO betaine CKD (4.1; 20.2), TEGO betaine L7 (7.5; 20.0), sodium dodecyl sulfate (7.5; 39.0), Triton X-100 (8.9; 110), polysorbate 80 (48.1; 491), soybean lecithin (7920; 19940).     

Inhibitory actions of glycyrrhizic acid on arylamine N-acetyltransferase activity in strains of Helicobacter pylori from peptic ulcer patients

Arylamine N-acetyltransferase (NAT) activities with 2-aminofluorene (2-AF) and p-aminobenzoic acid (PABA) as substrates were determined in Helicobacter pylori, collected from patients with peptic ulcers. The NAT activity was determined using an acetyl CoA recycling assay and high pressure liquid chromatography. Inhibition of growth studies from H. pylori demonstrated that glycyrrhizic acid elicited dose-dependent bactericidal effect in H. pylori cultures, i.e.; the greater the concentration of glycyrrhizic acid, the greater the inhibition of growth of H. pylori. Cytosols or suspensions of H. pylori with and without selected concentrations of glycyrrhizic acid co-treatment showed different percentages of 2-AF and PABA acetylation. The data indicated that there was decreased NAT activity associated with increased glycyrrhizic acid in H. pylori cytosols and intact cells. For the cytosol and intact bacteria examinations, the apparent values of Km and Vmax were decreased after co-treated with 80 M glycyrrhizic acid. This report is the first demonstration of glycyrrhizic acid inhibition of arylamine NAT activity and glycyrrhizic acid inhibition of growth in the bacterium H. pylori.     

Helicobacter pylori infection: relation with cardiovascular risk factors, ischaemic heart disease, and social class

OBJECTIVE: To determine whether Helicobacter pylori infection is associated with the development of ischaemic heart disease and whether such infection can explain the social class inequality in ischaemic heart disease. DESIGN: Cardiovascular risk factor levels, prevalence of ischaemic heart disease (Rose questionnaire angina, and/or a history of myocardial infarction), and serum antibodies to H pylori (enzyme linked immunosorbent assay) were assessed in a cross sectional population based survey. SETTING: Belfast and surrounding districts, Northern Ireland. PARTICIPANTS: 1182 men and 1198 women aged 25-64 years randomly selected from the Central Services Agency's general practitioner lists. MAIN OUTCOME MEASURES: The relation of H pylori infection with cardiovascular risk factors and ischaemic heart disease. The association of social class with ischaemic heart disease. RESULTS: Systolic and diastolic blood pressure, plasma viscosity, and total cholesterol were not associated with H pylori infection. A weak negative association existed between H pylori infection and fibrinogen (mean (SE) difference in fibrinogen between infected and uninfected individuals -0.09 (0.04) g/l, P = 0.02) and between infection in women and high density lipoprotein (HDL) cholesterol (mean (SE) difference in HDL cholesterol between infected and uninfected individuals -0.06 (0.02) mmol/l, P = 0.006). A potentially important association was demonstrated between H pylori infection and ischaemic heart disease but this did not reach statistical significance (odds ratio (95% confidence interval (CI) 1.51 (0.93 to 2.45), P = 0.1). Social class was associated with ischaemic heart disease independently of cardiovascular risk factors and H pylori infection (odds ratio, manual v non-manual (95% CI) 1.82 (1.14 to 2.91), P = 0.01). CONCLUSION: H pylori may be independently associated with the development of ischaemic heart disease but if this is so the mechanism by which this effect is exerted is not through increased concentration of plasma fibrinogen. H pylori infection does not explain the social class inequality in ischaemic heart disease which exists independently of known cardiovascular risk factors.     

The membrane-bound form of heparin-binding epidermal growth factor-like growth factor promotes survival of cultured renal epithelial cells

To understand whether expression of membrane-anchored heparin binding epidermal growth factor (proHB-EGF) is involved in renal epithelial cell survival, rat membrane-bound HB-EGF precursor was stably transfected into a renal epithelial cell line, NRK 52E cells (NRKproHB-EGF). When exposed to 10% fetal calf serum (FCS), there were no differences in growth rates among wild-type (WT), vector-transfected (NRKvector), and NRKproHB-EGF. However, when cells were grown in the presence of 1% FCS, the growth rate of NRKproHB-EGF was 65% faster. When confluent cell monolayers were exposed to H2O2 or etoposide, WT or NRKvector exhibited significant apoptotic bodies and DNA laddering; in contrast, NRKproHB-EGF were resistant to both stimuli, as indicated by increased cell viability and marked decrease of apoptotic bodies and DNA laddering. When plated at high density onto plastic dishes without FCS, WT and NRKvector formed few attachments, did not proliferate, and underwent apoptosis. By day 3, no cells survived. Addition of exogenous recombinant HB-EGF (10(-8) M) to WT or NRKvector increased cell survival by <10% and incubation with conditioned media of NRKproHB-EGF had no effect. In contrast, NRKproHB-EGF attached and formed epithelial colonies, although they did not proliferate. After 3 days, cell viability was 84% of the initial cell number plated, and no evidence of apoptosis was present. When plated in 10% FCS, NRKproHB-EGF attachment to plastic substratum at 1, 2, and 3 h was 250% greater than that of WT or NRKvector. Addition of exogenous recombinant human HB-EGF to WT or NRKvector increased attachment by <50%. When grown on poly(2-hydroxyethyl methacrylate) or in the presence of the integrin receptor-blocking peptide GRGDTP, neither WT nor NRKvector attached to the substratum or formed cell-cell attachments. Compared with WT or NRKvector, NRKproHB-EGF exhibited 300% greater cell viability on either poly(2-hydroxyethyl methacrylate)-coated dishes or in the presence of GRGDTP and formed cell clusters. When plated at low density (1 x 10(3) cells/1.5-cm dish) or at high density in the presence of an anti-HB-EGF blocking antibody, NRKproHB-EGF failed to form epithelial colonies. Addition of formalin fixed NRKproHB-EGF promoted EGF receptor tyrosine phosphorylation in quiescent A431 cells and stimulated DNA synthesis and prevented H2O2-induced apoptosis in renal epithelial cells. These results indicate that membrane-bound HB-EGF promotes renal epithelial cell survival, possibly by promoting cell-matrix and cell-cell interactions. The failure of either conditioned media or exogenous HB-EGF to reproduce these findings suggests that juxtacrine or tightly coupled paracrine interactions underlie this cytoprotection.     

Development of antibodies to fetal calf serum with arthus-like reactions in human immunodeficiency virus-infected patients given syngeneic lymphocyte infusions

In an attempt to restore immune competence to 12 human immunodeficiency virus-1 (HIV-1)-infected patients, lymphocytes from their HIV-1-uninfected identical twin siblings were cultured in medium supplemented with 5% fetal calf serum (FCS), anti-CD3 antibody, and interleukin-2 (100 IU/mL) for 10 days and then infused into the patients. After multiple infusions, at 6- to 8-week intervals, half of the patients developed arthus-like reactions within 4 to 12 hours of infusion consisting of fever > 39 degrees C, hypotension, rigors, arthralgias, myalgias, headache, and/or malaise. Preinfusion and postinfusion serum samples were evaluated for the presence of antibodies to FCS using double immunodiffusion. All preinfusion serum samples were negative by this method while 8 of the 12 patients developed antibodies to a single component of FCS after two or more infusions of lymphocytes cultured in FCS-supplemented medium. Prick skin testing to standardized beef extract was negative in all patients. There was a correlation between initial CD4 level and the development of antibodies to FCS (median initial CD4 count in FCS antibody positive patients = 362.0/microL v median initial CD4 count of nonresponders = 135.0/microL). There was no correlation with response to recall antigens in delayed-type hypersensitivity testing. We conclude that selected patients were sensitized to a single component of FCS carried on donor lymphocytes, despite thorough washing of the cells before infusion. The development of antibodies to FCS indicates that immune complex formation could have occurred after the cell infusions, resulting in the arthus-like reactions. These observations suggest that the therapeutic use of human lymphocytes cultured in FCS may expose the recipient to immunogenic substances with possible clinical sequelae.     

Growth and morphological transformations of Helicobacter pylori in broth media

Helicobacter pylori, a cause of peptic ulcer disease and certain types of gastric cancers, has usually been cultured on diverse agar-based media, resulting in a requirement for 2 to 4 days of growth at 37 degrees C. We have developed a novel broth medium consisting of a base medium supplemented with 2% newborn calf serum, Mg2+, Cu2+, Fe2+, Zn2+, Mn2+, and 1 mg of lysed human erythrocytes per ml. This medium supports rapid growth of H. pylori, with a doubling time of about 50 min. Optimal growth was obtained in a pH range higher than that supporting most other gram-negative bacteria (at pH 8.5). H. pylori cultured in this supplemented broth retains the spiral morphology seen in both histological sections and cultures from agar-based media and also retains a high urease activity. After 18 h in this broth, H. pylori transforms to a coccal form with a complete loss of urease activity. Previously these cocci have been reported to be senescent, since they could not be subcultured on agar medium. Our experiments suggest that some of the cocci can revert back to the spiral morphology with full recovery of urease activity when subcultured in fresh microaerobic broth medium.     

Amoxycillin resistance is one reason for failure of amoxycillin-omeprazole treatment of Helicobacter pylori infection

BACKGROUND: The efficacy of omeprazole and amoxycillin dual therapy to treat Helicobacter pylori infection has been inconsistent, suggesting the presence of host or bacterial factors influencing treatment success. The aim of this study was to assess the role of pre-treatment amoxycillin resistance in the efficacy of omeprazole and amoxycillin dual therapy. METHODS: We studied 43 consecutive dyspeptic patients with H. pylori infection. Pre-treatment H. pylori infection was established by the combination of positive rapid urease test, culture and histology. Amoxycillin susceptibility testing was performed by an Epsilometer test (E-test) method and amoxycillin resistance was defined as minimum inhibitory concentration greater than 8 microg/mL. Patients received 20 mg omeprazole twice daily for 28 days and amoxycillin 1000 mg twice daily for 2 weeks. Adverse effects were documented using a questionnaire. H. pylori status was reassessed 6-8 weeks after the end of treatment by rapid urease testing and histological examination of gastric biopsies. RESULTS: Forty-two dyspeptic patients completed the study, and one patient dropped out. H. pylori infection was cured in 2 3 of 42 patients (55%). The cure rate was higher in patients harbouring amoxycillin-sensitive organisms than in those with resistant strains: 66% (19/29) vs. 31% (4/13), respectively (P = 0.049). No significant differences in cure rates were evident in relation to age, sex, smoking habits or compliance. CONCLUSIONS: The effectiveness of amoxycillin-omeprazole dual therapy was greatly reduced in the presence of pre-treatment amoxycillin-resistant H. pylori. The success rate in patients with amoxycillin-sensitive H. pylori was only 66%, suggesting the presence of additional factors affecting the efficacy of this therapy.     

Functional dyspepsia, gastric emptying of solids, and Helicobacter pylori infection

The origin of functional dyspepsia (FD) is unknown, however, abnormal gastric emptying and infection by H. pylori have been suggested as possible causes. OBJECTIVE: The aim of this study was to test the hypothesis that infection by H. pylori could be related to alterations in gastric emptying of solids and play a role in the pathophysiology of dyspepsia. METHODS: Studies were performed on 12 controls: 6 males, 6 females, age 40 +/- 13, and on 45 FD patients: 15 males and 30 females, age 43.5 +/- 12. Clinical criteria for FD diagnosis were post-prandial epigastric pain, nausea, vomiting or epigastric bloating, with normal blood test, upper endoscopy and abdominal ultrasound. Diagnosis of H. pylori infection was either by growth positive on culture of antral biopsy or by all of the following: on Gram stain, urease test positive and visualization of microorganisms in the antral biopsy. Gastric emptying of solids was studied with a radio-nuclide technique. Patients were prospectively classified in 4 groups according to the main symptom: reflux-like, ulcer-like, dysmotility, and non-specific. RESULTS: H. pylori infection was observed in 21/32 (66%) FD patients. No significant differences in the gastric emptying of solids between the control group and patients with FD (tl/2 80 +/- 17 minutes vs 75 +/- 16 min). The presence of H. pylori infection did not influence gastric emptying rates (78 +/- 16 minutes in infected patients vs 73 +/- 15 min in non infected patients). Gastric emptying times were similar among the four subgroups of FD patients. CONCLUSIONS: No significant differences in gastric emptying of solids were found in H. pylori infected persons as compared with the controls. These findings suggest that H. pylori infection and/or changes in gastric emptying of solids do not play a role in the pathophysiology of FD.     

The importance of increasing the number of gastric biopsies in the diagnosis of Helicobacter pylori

BACKGROUND/AIMS: The role of Helicobacter pylori in various gastroduodenal diseases is universally accepted. In this study, we aimed to determine the proper number and sites of the gastric biopsies in order to achieve the highest diagnostic yield through the use of a urease test and histopathology. We also compared the histological findings encountered in patients who had Helicobacter pylori (H. pylori) colonization. METHODOLOGY: Fifty patients referred for upper gastrointestinal endoscopy for dyspeptic complaints were included in the study. Our mapping protocol included 2 biopsies from antrum and 2 biopsies from corpus. We obtained 2 biopsies from each biopsy site for urease test and histopathological assessment. Golden standard positivity for the presence of H. pylori colonization was defined as concomitantly positive urease test and histologically detected bacteria found at the same biopsy site. RESULTS: Forty-three patients had H. pylori colonization. Colonization rates of H. pylori, sensitivities of urease testing, and histopathology in 4 biopsy sites were not statistically different. Sensitivity of urease testing was 81.4% for 1 biopsy and 100% for 4 cumulative biopsies. Sensitivities of histological assessment were 93% and 100% for 1 and 4 biopsies, respectively. CONCLUSIONS: Results of this study suggest that 2 biopsies for urease testing and 1 biopsy for histopathology obtained from the antrum or corpus of the stomach were sufficient to obtain the highest statistically significant diagnostic sensitivity.     

Helicobacter pylori infection in the etiopathogenesis of duodenal ulcer in children

The study evaluates the frequency of Helicobacter pylori (H. pylori) infection, as well as systemic cellular immune response to H. pylori in children with duodenal ulcer (DU). The study group comprised 47 children with DU, aged 6-17 (mean 13, 1 +/- 4, 2). H. pylori detection was based on urease test, histology, culture and serologic tests. Endoscopic and morphologic findings were analysed according to Sydney System criteria. In 12 children from the overmentioned group subsets of blood lymphocytes B and T (CD3, CD4, CD8, CD3/DR, CD19) and NK cells, some neutrophils functions (phagocytosis, chemiluminescence) and phagocytes receptors before and one month after H. pylori triple treatment were investigated. H. pylori infection was detected in 44 of the investigated children. In addition, pathologic examination revealed chronic gastritis in 44 children and chronic duodenitis in 42 of them. In immunosystemic examination decreased percentage of CD8 lymphocytes and NK cells, increased CD4/CD8 ratio, decreased mitogen-induced response and changes of function and receptor expression of neutrophils were found. After H. pylori treatment in follow-up endoscopy no ulcers were found and histologic examination did not reveal chronic active gastroduodenitis, while the rate of nonactive gastritis was increased. Eradication of H. pylori infection in 41 children and normalisation of immune parameters in 11 children were obtained. The results of our investigation indicate, that H. pylori infection plays an important role in the pathogenesis of DU in children.     

Iron acquisition by Helicobacter pylori: importance of human lactoferrin

Helicobacter pylori is known to be an etiologic agent of gastritis and peptic ulcer disease in humans. However, the mechanism by which this organism acquires iron has not been studied. For this investigation, H. pylori was grown in iron-restricted medium. Siderophore production was not detected by chemical assays, and the strains were unable to use enterochelin and pyochelin for growth in low-iron media. Human lactoferrin supported full growth of the bacteria in media lacking other iron sources, but neither human transferrin, bovine lactoferrin, nor hen ovotransferrin served as a source for iron. Since lactoferrin was found in significant amounts in human stomach resections with superficial or atrophic gastritis, the iron acquisition system of H. pylori by the human lactoferrin receptor system may play a major role in the virulence of H. pylori infection.     

Helicobacter pylori generates superoxide radicals and modulates nitric oxide metabolism

During studies of the bactericidal action of nitric oxide (NO), we found that it reversibly inhibited the respiration of Escherichia coli and irreversibly inhibited the respiration of Helicobacter pylori. Peroxynitrite, a reaction product of NO and superoxide, irreversibly inhibited the respiration of both H. pylori and E. coli. H. pylori, but not E. coli, generated substantial amounts of superoxide radicals. These results suggest that NO directly inhibits the respiration of E. coli whereas it rapidly reacts with endogenously generated superoxide radicals in H. pylori. The resulting peroxynitrite inactivates the respiration of H. pylori.     

Fibrinolytic components in nasal mucosa and nasal secretion

Effects of a newly synthesized antiulcer agent, YJA20379-4, on gastric proton pump (H+/K+-ATPase) activity, Helicobacter pylori (H. pylori) growth, gastric acid secretion, and gastro-duodenal lesions, were examined in comparison with those of omeprazole. YJA20379-4 markedly inhibited the H+/K+-ATPase activity in a concentration-dependent manner and the inhibitory effect was increased under a weak acidic condition; the IC50 values were 32 and 81 microM at pH 6.4 and 7.4, respectively. The inhibition was completely antagonized by 0.5 mM dithiothreitol (DTT). In addition, YJA20379-4 showed a significant anti-H. pylori activity determined by the agar dilution method. The value of minimum inhibitory concentration (MIC, 3.9-11.7 microg/ml) was at least 3 times more potent than that of omeprazole. In pylorus ligated rats, YJA20379-4 inhibited basal gastric acid secretion when administered by the intraduodenal route (ED50: 23.6 mg/kg). In experimental ulcer models, YJA20379-4 administered by the oral route dose-dependently prevented the development of gastro-duodenal lesions in rats. Moreover, repeated administration of YJA20379-4 promoted the healing of gastric ulcers induced by acetic acid. On the basis of the data obtained, it is suggested that YJA20379-4 has a wide spectrum of antiulcer activities, and its mode of antiulcer actions is dependent on the inhibition of H+/K+-ATPase activity and H. pylori growth and the enhancement of a mucosal defense. Thus, YJA20379-4 might prove to be a beneficial therapy for gastritis and peptic ulcer diseases.     

Antibiotic properties of bovine lactoferrin on Helicobacter pylori

To investigate a potential new treatment for gastric Helicobacter pylori infection, we have examined the use of the natural antibiotic lactoferrin, found in bovine milk, for activity against Helicobacter species both in vitro and in vivo. Lactoferrin was bacteriostatic to H. pylori when cultured at concentrations > or =0.5 mg/ml. Growth of H. pylori was not inhibited by another milk constituent, lysozyme, or by a metabolite of lactoferrin, lactoferricin B, but growth was inhibited by the iron chelator deferoxamine mesylate. Lactoferrin inhibition of growth could be reversed by addition of excess iron to the medium. Lactoferrin in retail dairy milk was found to be more stable intragastrically than unbuffered, purified lactoferrin. Treatment of H. felis-infected mice with lactoferrin partially reversed mucosal disease manifestations. It is concluded that bovine lactoferrin has significant antimicrobial activity against Helicobacter species in vitro and in vivo. Bovine lactoferrin should be further investigated for possible use in H. pylori infections in man.     

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.     

Antagonistic activity against Helicobacter infection in vitro and in vivo by the human Lactobacillus acidophilus strain LB

The purpose of the present study was to examine the activity of the human Lactobacillus acidophilus strain LB, which secretes an antibacterial substance(s) against Helicobacter pylori in vitro and in vivo. The spent culture supernatant (SCS) of the strain LB (LB-SCS) dramatically decreased the viability of H. pylori in vitro independent of pH and lactic acid levels. Adhesion of H. pylori to the cultured human mucosecreting HT29-MTX cells decreased in parallel with the viability of H. pylori. In conventional mice, oral treatment with the LB-SCS protected against infection with Helicobacter felis. Indeed, at both 8 and 49 days post-LB-SCS treatment (29 and 70 days postinfection), inhibition of stomach colonization by H. felis was observed, and no evidence of gastric histopathological lesions was found. LB-SCS treatment inhibits the H. pylori urease activity in vitro and in H. pylori that remained associated with the cultured human mucosecreting HT29-MTX cells. Moreover, a decrease in urease activity was detected in the stomach of the mice infected with H. felis and treated with LB-SCS.     

Impaired male sexual development in perinatal Sprague-Dawley and Long-Evans hooded rats exposed in utero and lactationally to p,p''-DDE

The evolution of gastric mucosa-associated lymphoid tissue (MALT) lymphoma is a multi-stage process, comprising the sequential development of chronic H. pylori-associated gastritis, low grade and high grade lymphoma. The genesis of MALT lymphoma embodies the mechanisms of both physiological immune responses and the acquisition of genetic abnormalities. The tumour probably originates from an autoreactive MALT marginal zone B cell, which is generated during H. pylori infection. As a consequence of a genotoxic insult induced by H. pylori infection, the progenitor tumour cell may become genetically unstable and develop genetic abnormalities such as the t(11;18) translocation, trisomy three, c-myc and p53 mutations during a phase of expansion, which lead to partial transformation. With the growth help from H. pylori specific T cells, this abnormal B cell clone may undergo clonal expansion and gradually form a low grade MALT lymphoma. Additional genetic abnormalities including the t(1;14) translocation and other uncharacterised events could completely transform this abnormal B cell clone and result in escape from T cell dependency. Finally, further genetic events such as complete inactivation of the tumour suppressor genes p53 and p16, and possible activation of c-myc oncogene by translocation or other undetermined abnormalities can result in high grade transformation     

Production of chemoattractant by Helicobacter pylori

Helicobacter pylori is present in the antral region of the stomach in a majority of patients with gastritis type B. The specific mechanism whereby the organism participates in the development of disease remains uncertain. Since the organism is not invasive, we postulate that H. pylori produces a chemoattractant that recruits inflammatory cells to the antral region of the stomach. H. pylori was grown under microaerophilic conditions at 37 degrees C for 72 hr in Brucella broth containing 1% fetal bovine serum. Culture supernates were harvested after removal of organisms by centrifugation and filtration. The putative chemoattractant in culture supernates as well as that which might be present endogenously in the growth medium (negative control) was assayed against human neutrophils (PMN) in modified Boyden blind-well chambers using 3.0-microns membranes. We found that H. pylori supernates are chemotactic and showed up to 130% activity when compared to the positive chemoattractant control (zymosan-activated serum, a source of C5a). Minimal activity was observed with virgin growth medium. The chemoattractant activity is proportional to the number of colony forming units (CFU) of H. pylori. Preliminary characterization of the activity shows that the chemoattractant is stable in a boiling water bath for 15 min, activity is lost within 1 hr in acid or alkali, and the chemotactic factor has an approximate molecular weight of 8500 daltons. The factor has no amino-sugar and is negative for the lipid A portion of lipopolysaccharide.(ABSTRACT TRUNCATED AT 250 WORDS)     

Major proteins of bovine seminal plasma and high-density lipoprotein induce cholesterol efflux from epididymal sperm

One of the hypotheses to explain the mechanism of capacitation involves the loss of sperm membrane cholesterol. Here, we studied whether or not the major proteins of bovine seminal plasma designated as BSP-A1, -A2, -A3, and -30-kDa (collectively called BSP proteins), which are implicated in sperm capacitation, induce cholesterol efflux. When epididymal sperm were labeled with [3H]cholesterol and incubated with bovine seminal plasma (0.05-2%) or BSP proteins (20-120 microg/ml) for 8 h, the sperm lost [3H]cholesterol (3.6-fold and 3-fold, respectively). The same results in the presence of BSP-A1/-A2 were obtained (3.5-fold) by direct determination of cholesterol on unlabeled epididymal sperm. Analysis of efflux particles by ultracentrifugation on a sucrose gradient revealed a single symmetrical peak of radioactivity at 1.14 g/ml. Immunoblotting of the fractions obtained from size-exclusion chromatography of the efflux particles showed that a portion of the BSP proteins were associated with [3H]cholesterol. Heparin (12 microg/ml) alone did not stimulate cholesterol efflux. In contrast, high-density lipoprotein (HDL, 100 microg/ml) alone stimulated cholesterol efflux up to 3.1-fold after 8 h. When labeled epididymal sperm were preincubated for 20 min with BSP-A1/-A2 (120 microg/ml), washed, and incubated with HDL (100 microg/ml) for 8 h, the total cholesterol efflux of the sperm suspension was 51.8 +/- 5.0% compared to 39.3 +/- 1.2% when HDL alone was used. These results indicate that BSP proteins and HDL play an important role in the sperm sterol efflux that occurs during capacitation. Furthermore, the heparin-induced sperm capacitation did not involve the efflux of sperm membrane cholesterol.     

Helicobacter pylori and gastroduodenal lesions in 547 symptomatic young adults

OBJECTIVES: Helicobacter pylori (H. pylori) is involved in the pathogenesis of gastric inflammatory disorders. Both antral chronic gastritis and H. pylori infection prevalence increase with age. The aim of the study was to assess the prevalence of H. pylori infection in young adults and to study the relationship between endoscopical and histological features and H. pylori infection. METHODS: The study concerned 547 young patients (age: 18-25 years), undergoing endoscopy for upper gastrointestinal symptoms. The severity and the activity of chronic gastritis was graded by histological examination of antral biopsies. The diagnosis of H. pylori infection was based on histology and culture or urease test. RESULTS: Fifty-three percent of the patients had a normal endoscopy; 44 ulcers were found: 34 duodenal ulcers and 10 gastric ulcers. H. pylori infection was detected in 34% of cases. The prevalence of H. pylori infection was 29.8% in non-ulcer patients, 50% in gastric ulcers and 91% in duodenal ulcers (P < 0.01). Duodenal ulcer, aspect of antral mosaic mucosa and nodular gastritis, were closely related to the presence of H. pylori. There was a significant relationship between H. pylori infection and both the severity (P < 0.01) and the activity (P < 0.01) of the antral chronic gastritis. The prevalence of follicular gastritis was 22% : it was present in 60% of H. pylori positive patients and 2.4% of H. pylori negative patients. H. pylori infection was more frequent in patients from Africa than in Europeans (P < 0.01). There was no significant association between H. pylori infection and different types of diets, settlements (rural vs urban) or symptoms. CONCLUSION: These results show that in the young population studied, duodenal ulcer, nodular gastritis, antral mosaic mucosa, active chronic gastric and follicular gastritis are closely related to H. pylori infection. They suggest that in the subgroup of non ulcer symptomatic patients, H. pylori prevalence is higher than in the general population.