Biomedical subjects

H Matsui

Publications and source records attributed to H Matsui.

At least 109 records · Page 6Linked to original sources

PubMed2001

Diet-dependent shifts in the bacterial population of the rumen revealed with real-time PCR.

A set of PCR primers was designed and validated for specific detection and quantification of Prevotella ruminicola, Prevotella albensis, Prevotella bryantii, Fibrobacter succinogenes, Selenomonas ruminantium-Mitsuokella multiacida, Streptococcus bovis, Ruminococcus flavefaciens, Ruminobacter amylophilus, Eubacterium ruminantium, Treponema bryantii, Succinivibrio dextrinosolvens, and Anaerovibrio lipolytica. By using these primers and the real-time PCR technique, the corresponding species in the rumens of cows for which the diet was switched from hay to grain were quantitatively monitored. The dynamics of two fibrolytic bacteria, F. succinogenes and R. flavefaciens, were in agreement with those of earlier, culture-based experiments. The quantity of F. succinogenes DNA, predominant in animals on the hay diet, fell 20-fold on the third day of the switch to a grain diet and further declined on day 28, with a 57-fold reduction in DNA. The R. flavefaciens DNA concentration on day 3 declined to approximately 10% of its initial value in animals on the hay diet and remained at this level on day 28. During the transition period (day 3), the quantities of two ruminal prevotella DNAs increased considerably: that of P. ruminicola increased 7-fold and that of P. bryantii increased 263-fold. On day 28, the quantity of P. ruminicola DNA decreased 3-fold, while P. bryantii DNA was still elevated 10-fold in comparison with the level found in animals on the initial hay diet. The DNA specific for another xylanolytic bacterium, E. ruminantium, dropped 14-fold during the diet switch and was maintained at this level on day 28. The concentration of a rumen spirochete, T. bryantii, decreased less profoundly and stabilized with a sevenfold decline by day 28. The variations in A. lipolytica DNA were not statistically significant. After an initial slight increase in S. dextrinosolvens DNA on day 3, this DNA was not detected at the end of the experiment. S. bovis DNA displayed a 67-fold increase during the transition period on day 3. However, on day 28, it actually declined in comparison with the level in animals on the hay ration. The amount of S. ruminantium-M. multiacida DNA also increased eightfold following the diet switch, but stabilized with only a twofold increase on day 28. The real-time PCR technique also uncovered differential amplification of rumen bacterial templates with the set of universal bacterial primers. This observation may explain why some predominant rumen bacteria have not been detected in PCR-generated 16S ribosomal DNA libraries.

Animal Feed↗

PubMed2001

Disruption of the genes for ClpXP protease in Salmonella enterica serovar Typhimurium results in persistent infection in mice, and development of persistence requires endogenous gamma interferon and tumor necrosis factor alpha.

The enteric pathogen Salmonella enterica serovar Typhimurium, similar to other facultative intracellular pathogens, has been shown to respond to the hostile conditions inside macrophages of the host organism by producing a set of stress proteins that are also induced by various environmental stresses. The stress-induced ClpXP protease is a member of the ATP-dependent proteases, which are known to be responsible for more than 90% of all proteolysis in Escherichia coli. To investigate the contribution of the ClpXP protease to the virulence of serovar Typhimurium we initially cloned the clpP and clpX operon from the pathogenic strain serovar Typhimurium chi3306 and then created insertional mutations in the clpP and/or clpX gene. The Delta clpP and Delta clpX mutants were used to inoculate BALB/c mice by either the intraperitoneal or the oral route and found to be limited in their ability to colonize organs of the lymphatic system and to cause systemic disease in the host. A variety of experiments were performed to determine the possible reasons for the loss of virulence. An oxygen-dependent killing assay using hydrogen peroxide and paraquat (a superoxide anion generator) and a serum killing assay using murine serum demonstrated that all of the serovar Typhimurium Delta clpP and Delta clpX mutants were as resistant to these killing mechanisms as the wild-type strain. On the other hand, the macrophage survival assay revealed that all these mutants were more sensitive to the intracellular environment than the wild-type strain and were unable to grow or survive within peritoneal macrophages of BALB/c mice. In addition, it was revealed that the serovar Typhimurium ClpXP-depleted mutant was not completely cleared but found to persist at low levels within spleens and livers of mice. Interferon gamma-deficient mice and tumor necrosis factor alpha-deficient mice failed to survive the attenuated serovar Typhimurium infections, suggesting that both endogenous cytokines are essential for regulation of persistent infection with serovar Typhimurium.

Adenosine Triphosphatases↗

PubMed2001

Virulence plasmid-borne spvB and spvC genes can replace the 90-kilobase plasmid in conferring virulence to Salmonella enterica serovar Typhimurium in subcutaneously inoculated mice.

In a mouse model of systemic infection, the spv genes carried on the Salmonella enterica serovar Typhimurium virulence plasmid increase the replication rate of salmonellae in host cells of the reticuloendothelial system, most likely within macrophages. A nonpolar deletion in the spvB gene greatly decreased virulence but could not be complemented by spvB alone. However, a low-copy-number plasmid expressing spvBC from a constitutive lacUV5 promoter did complement the spvB deletion. By examining a series of spv mutations and cloned spv sequences, we deduced that spvB and spvC could be sufficient to confer plasmid-mediated virulence to S. enterica serovar Typhimurium. The spvBC-bearing plasmid was capable of replacing all of the spv genes, as well as the entire virulence plasmid, of serovar Typhimurium for causing systemic infection in BALB/c mice after subcutaneous, but not oral, inoculation. A point mutation in the spvBC plasmid preventing translation but not transcription of spvC eliminated the ability of the plasmid to confer virulence. Therefore, it appears that both spvB and spvC encode the principal effector factors for Spv- and plasmid-mediated virulence of serovar Typhimurium.

ADP Ribose Transferases↗

PubMed2001

Mouse testicular Leydig cells express Klk21, a tissue kallikrein that cleaves fibronectin and IGF-binding protein-3.

We have cloned a type of cDNA for a functional glandular kallikrein, designated as mouse Klk21 (mKlk21), from the adult mouse testis cDNA library. mKlk21 was expressed in the kidney, submaxillary glands, and testis of the mouse. In the testis, mKlk21 mRNA was detectable at 4 wk of postnatal development and became more prominent thereafter. The mKlk21 gene was expressed exclusively in the Leydig cells of adult mice. When Leydig cells isolated from 2-wk-old mouse testis were cultured in the presence of T, mKlk21 expression was induced significantly. Active recombinant mKlk21 showed trypsin-like specificity, favorably cleaving Arg-X bonds of synthetic peptide substrates. The enzyme activity was strongly inhibited with typical serine protease inhibitors. mKlk21 hydrolyzed casein, gelatin, fibronectin, and IGF-binding protein-3 (IGFBP-3). As in mKlk21, IGF-I and IGFBP-3 were expressed in the Leydig cells of the adult mouse testis, although the transcript of IGFBP-3 was not detected in all of the observed cells. The culture medium of Leydig cells isolated from adult mouse testes contained an mKlk21-like enzyme activity capable of degrading IGFBP-3. These results suggest that mKlk21 plays a role in Leydig cell function in the adult mouse testis.

Amino Acid Sequence↗

PubMed2001

Cloning and characterization of a rat ortholog of MMP-23 (matrix metalloproteinase-23), a unique type of membrane-anchored matrix metalloproteinase and conditioned switching of its expression during the ovarian follicular development.

In our attempt to study the role of matrix metalloproteinases (MMPs) in the process of mammalian ovulation, we isolated a rat ortholog of the recently reported human MMP-23 from gonadotropin-primed immature rat ovaries. Transient expression of epitope-tagged rat and human MMP-23 in COS-1 cells revealed that they were synthesized as a membrane-anchored glycoprotein with type II topology. Indirect immunofluorescent analysis showed that subcellular localization of MMP-23 was predominantly in the perinuclear regions. The transfected human MMP-23 protein was processed endogenously to the soluble form in COS-1 cells. However, cotransfection of MMP-23 with the mouse furin cDNA did not enhance this processing, indicating that furin may not be involved in this event. Notably, in situ hybridization analysis revealed a dramatic switching of MMP-23 mRNA localization from granulosa cells to theca-externa/fibroblasts and ovarian surface epithelium during the follicular development. In serum-free primary culture of rat granulosa cells, a drastic diminution of MMP-23 mRNA expression was observed in response to FSH action between 24 h and 48 h of culture. The observed effect of FSH on MMP-23 expression was mimicked by treatment of granulosa cells with forskolin or 8-bromo (Br)-cAMP. In contrast, MMP-23 mRNA levels increased in theca-interstitial cells regardless of the presence of LH in the culture. However, treatment of theca-interstitial cells with forskolin or 8-Br-cAMP markedly reduced the expression of MMP-23 with a concomitant increase in progesterone production. These results indicate that the MMP-23 gene is spatially and temporally regulated in a cell type-specific manner in ovary via the cAMP signaling pathway.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2001

A novel series of thromboxane A2 synthetase inhibitors with free radical scavenging and anti-peroxidative activities.

A novel series of indoline derivatives with imidazole and carboxyl moieties were synthesized and evaluated for their thromboxane A2 (TXA2) synthetase inhibiting, radical scavenging and anti-peroxidative activities. Among the compounds synthesized, 3-[5-substituted-3-[2-(imidazol-1-yl)ethyl]indolin-1-yl]propionic acids showed free radical scavenging activity and inhibitory effects on lipid-peroxidation of rat brain homogenate and on arachidonate-induced TXA2-dependent aggregation of rabbit platelets. The anti-platelet and anti-peroxidative activities were related to the lipophilicity of the 5-substituent. The 5-hexyloxy derivative (13) showed about 35-fold higher inhibitory activity on TXA2 synthesis than that of ozagrel and about 100-fold higher activity on lipid peroxidation than that of alpha-tocopherol. Compound 13 showed in vivo anti-thrombotic effect in mice and ex vivo anti-peroxidative activity in rats.

Animals↗

PubMed2001

Left ventricular relaxation abnormality is detectable by analysis of the relaxation time constant in patients with atrial fibrillation.

Left ventricular (LV) contractility is constantly changing during atrial fibrillation (AF), which is dependent on the force-interval relationships. However, no information has been available on LV relaxation in patients with both AF and impaired LV systolic function. LV pressure was measured with a catheter-tipped micromanometer and the time constant of isovolumic LV pressure decline (tau(bf)) was calculated with best exponential fitting from more than 10 consecutive beats. Patients with AF (5 with mitral valvular disease, 6 with idiopathic dilated cardiomyopathy, and 1 with no underlying disease) were subdivided into 2 groups: group A, with ejection fraction (EF) <0.5 (n=7); and group B, with EF > or =0.5 (n=5). Linear correlation coefficients (r) between tau and RR2, RR2/RR1, LV peak systolic pressure (peak LVP) were calculated. Although tau did not show a discrepancy between the 2 groups, tau(bf) correlated better with RR2/RR1 only in the group A patients. The relation between tau and peak LVP showed a good correlation with a steep slope (R, Deltatau/Deltapeak LVP) only in the group A patients (accentuated afterload-dependence). R was significantly different between the 2 groups. Thus, a beat-to-beat analysis of tau may be a practical and feasible way for detecting LV relaxation abnormality in patients with AF.

Adult↗

PubMed2001

Right ventricular cardiomyopathy accompanied by protein-losing enteropathy and chylous effusion.

Severe right-side heart failure developed in a 47-year-old Japanese woman who suffered from hypoalbuminemia and a massive right side chylous pleural effusion. She had been diagnosed as having protein-losing enteropathy with right ventricular cardiomyopathy. Autopsy showed congenital anomalies of the lymph ducts and abnormal deposition of fibrous and fatty tissue in the right ventricular myocardium. The clinical and pathological findings are consistent with the nonarrythmogenic form of the arrythmogenic right ventricular dysplasia.

Adult↗

PubMed2001

Adenine deaminase activity of the yicP gene product of Escherichia coli.

During previous work on deriving inosine-producing mutants of Escherichia coli, we observed that an excess of adenine added to the culture medium was quickly converted to hypoxanthine. This phenomenon was still apparent after disruption of the known adenosine deaminase gene (add) on the E. coli chromosome, suggesting that, like Bacillus subtilis, E. coli has an adenine deaminase. As the yicP gene of E. coli shares about 35% identity with the B. subtilis adenine deaminase gene (ade), we cloned yicP from the E. coli genome and developed a strain that overexpressed its product. The enzyme was purified from a cell extract of E. coli harboring a plasmid containing the cloned yicP gene, and had significant adenine deaminase [EC 3.5.4.2] activity. It was deduced to be a homodimer, each subunit having a molecular mass of 60 kDa. The enzyme required manganese ions as a cofactor, and adenine was its only substrate. Its optimum pH was 6.5-7.0 and its optimum temperature was 60 degrees C. The apparent Km for adenine was 0.8 mM.

Aminohydrolases↗

PubMed2001

Major isoforms of starch branching enzymes in premature seeds of kidney bean (Phaseolus vulgaris L.).

Developing seeds of the kidney bean (Phaseolus vulgaris L.) contain several isoforms of starch branching enzymes. Two of them, KBE1 and KBE2, which are the major forms in the premature seeds, were purified as a single band of protein on SDS-PAGE and native PAGE by chromatographies on DEAE-Sepharose, Bio-Gel P-200, and amylose-binding Sepharose 6B. The enzymes had similar pH optimum (7.0), pH stability (7.0-9.5), temperature optimum (25-30 degrees C), and temperature stability (up to 40 degrees C). Additionally, both were inhibited by various divalent metal ions and activated by citrate. Finally, though their N-terminal amino acid sequences were identical, their molecular masses and affinities for amylose differed; 80 kDa and 1.27 mM for KBE1 and 77 kDa and 0.74 mM for KBE2.

1,4-alpha-Glucan Branching Enzyme↗

PubMed2001

gsk disruption leads to guanosine accumulation in Escherichia coli.

We tried some improvement of inosine production using an inosine-producing mutant of Escherichia coli which is deficient in purF (phosphoribosylpyrophosphate (PRPP) amidotransferase gene), purA (succinyl-adenosine 5'-monophosphate (AMP) synthetase gene), deoD (purine nucleoside phosphorylase gene), purR (purine repressor gene) and add (adenosine deaminase gene), and harboring the desensitized PRPP amidotransferase gene as a plasmid. The guaB (inosine 5'-monophosphate (IMP) dehydrogenase gene) disruption brought about a slightly positive effect on the inosine productivity. Alternatively, the gsk (guanosine-inosine kinase gene) disruption caused a considerable amount of guanosine accumulation together with a slight increase in the inosine productivity. The further addition of guaC (guanosine 5'-monophosphate (GMP) reductase gene) disruption did not lead to an increased guanosine accumulation, but brought about the decrease of inosine accumulation.

Chromatography, High Pressure Liquid↗

PubMed2001

1-Aminocyclopropane-1-carboxylate synthase of Penicillium citrinum: primary structure and expression in Escherichia coli and Saccharomyces cerevisiae.

A plant hormone, ethylene, is formed through 1-aminocyclopropane-1-carboxylic acid (ACC). A fungus, Penicillium citrinum, was found to synthesize ACC and to degrade ACC into 2-oxobutyrate and ammonia. ACC synthase, responsible for ACC synthesis in P. citrinum, was characterized on the molecular level by sequencing of N terminal and proteolytic peptides of the enzyme, and cloning and sequencing of its cDNA. The ACC synthase from P. citrinum had 430 amino acid residues and a shorter C terminal than the plant enzyme. The enzyme purified from Escherichia coli transformed with ACC-synthase-encoding DNA showed similar properties to those of the purified enzyme from P. citrinum. Saccharomyces cerevisiae with ACC synthase accumulated ACC in the medium with increasing time of incubation. The sequence of ACC synthase from P. citrinum was compared with that of the plant enzyme with discussion about important residues for catalysis.

Amino Acid Sequence↗

PubMed2001

Purification and substrate specificity of honeybee, Apis mellifera L., alpha-glucosidase III.

Alpha-glucosidase III, which was different in substrate specificity from honeybee alpha-glucosidases I and II, was purified as an electrophoretically homogeneous protein from honeybees, by salting-out chromatography, DEAE-cellulose, DEAE-Sepharose CL-6B, Bio-Gel P-150, and CM-Toyopearl 650M column chromatographies. The enzyme preparation was confirmed to be a monomeric protein and a glycoprotein containing about 7.4% of carbohydrate. The molecular weight was estimated to approximately 68,000, and the optimum pH was 5.5. The substrate specificity of alpha-glucosidase III was kinetically investigated. The enzyme did not show unusual kinetics, such as the allosteric behaviors observed in alpha-glucosidases I and II, which are monomeric proteins. The enzyme was characterized by the ability to rapidly hydrolyze sucrose, phenyl alpha-glucoside, maltose, and maltotriose, and by extremely high Km for substrates, compared with those of alpha-glucosidases I and II. Especially, maltotriose was hydrolyzed over 3 times as rapidly as maltose. However, maltooligosaccharides of four or more in the degree of polymerization were slowly degraded. The relative rates of the k0 values for maltose, sucrose, p-nitrophenyl alpha-glucoside and maltotriose were estimated to be 100, 527, 281 and 364, and the Km values for these substrates, 11, 30, 13, and 10 mM, respectively. The subsite affinities (Ai's) in the active site were tentatively evaluated from the rate parameters for maltooligosaccharides. In this enzyme, it was peculiar that the Ai value at subsite 3 was larger than that of subsite 1.

Animals↗

PubMed2001

Purification and identification of the essential ionizable groups of honeybee, Apis mellifera L., trehalase.

Trehalase (EC 3.2.1.28) of the bound type was purified as an electrophoretically homogeneous protein from adult honeybees by fractionation with ammonium sulfate, hydrophobic chromatography, and DEAE-Sepharose CL-6B, CM-Sepharose CL-6B, butyl-Toyopearl 650M, and p-aminophenyl beta-glucoside Sepharose 4B column chromatographies. The enzyme preparation was confirmed to be a monomeric protein containing 3.1% carbohydrate. The molecular weight was estimated to be approximately 69,000, and the optimum pH was 6.7. The Michaelis constant (Km) was 0.66 mM, and the molecular activity (k0) was 86.2 s(-1). The enzyme was an "inverting" type which produced beta-glucose from alpha, alpha-trehalose. Dependence of the V and Km values on pH gave values for the ionization constants, pKe1 and pKe2, of essential ionizable groups 1 and 2 of the free enzyme of 5.3 and 8.5, respectively. When the dielectric constant of the reaction mixture was decreased, pKe1, and pKe2 were shifted to higher values of + 0.2 and + 0.5 pH unit, respectively. The ionization heat (deltaH) of ionizable group 1 was estimated to be + 1.8 kcal/mol, and the deltaH value of group 2 was + 1.5 kcal/mol. These findings strongly support the notion that the essential ionizable groups of honeybee trehalase are two kinds of carboxyl groups, one being a dissociated type (-COO(-), ionizable group 1) and the other a protonated type (-COOH, ionizable group 2), although the pKe2 value is high.

Animals↗

PubMed2001

Investigation of various genotype characteristics for inosine accumulation in Escherichia coli W3110.

For the derivation of an inosine-overproducing strain from the wild type microorganism, it is known that the addition of an adenine requirement, removal of purine nucleoside hydrolyzing activity, removal of the feedback inhibition, and repression of key enzymes in the purine nucleotides biosynthetic pathway are essential. Thus, the disruption of purA (adenine requirement), deoD (removal of purine nucleosides phosphorylase activity), purR (derepression of the regulation of purine nucleotides biosynthetic pathway), and the insensitivity of the feedback inhibition of phosphoribosylpyrophosphate (PRPP) amidotransferase by adenosine 5'-monophosphate (AMP) and guanosine 5'-monophosphate (GMP) were done in the Escherichia coli strain W3110, and then the inosine productivity was estimated. In the case of using a plasmid harboring the PRPP amidotransferase gene (purF) that encoded a desensitized PRPP amidotransferase, purF disrupted mutants were used as the host strains. It was found that the innovation of the four genotypes brought about a small amount of inosine accumulation. Furthermore, an adenine auxotrophic mutant of E. coli showed inappropriate adenine use because its growth could not respond efficiently to the concentration of adenine added. As the presence of adenosine deaminase is well known in E. coli and it is thought to be involved in adenine use, a mutant disrupted adenosine deaminase gene (add) was constructed and tested. The mutant, which is deficient in purF, purA, deoD, purR, and add genes, and harboring the desensitized purF as a plasmid, accumulated about 1 g of inosine per liter. Although we investigated the effects of purR disruption and purF gene improvement, unexpectedly an increase in the inosine productivity could not be found with this mutant.

Adenosine Deaminase↗

PubMed2001

Impaired nitric oxide production and enhanced autoregulation of coronary circulation in young spontaneously hypertensive rats at prehypertensive stage.

In the current study, we investigated the NO-generation pathway in response to mechanical stimuli in SHR at the prehypertensive stage. To examine the role of NO in coronary autoregulation, we evaluated the effects of L-NAME on the coronary flow in SHR at both the prehypertensive and hypertensive stages. Isolated perfused hearts from 5- and 15-week-old SHR and from age-matched Wistar-Kyoto rats (WKY) were used. After stabilization at 60 mmHg, perfusion pressure was immediately raised to 90 mmHg to record the change in coronary flow for 10 min without (control) or with NO synthesis blockade by Nomega-nitro-L-arginine methyl ester (L-NAME). NOx- (nitrite/nitrate) was measured in coronary effluent. At 5 weeks of age, SHR did not have hypertension, while the coronary autoregulation was enhanced. L-NAME did not affect this enhanced autoregulation in 5-week-old SHR. At perfusion pressures of both 60 and 90 mmHg, 5-week-old SHR showed less coronary NOx- production than age-matched WKY. At 15 weeks, SHR showed a higher blood pressure than WKY. The coronary autoregulation in SHR remained higher than that in WKY, but was below that in 5-week-old SHR. NOx- production in 15-week-old SHR recovered to the level of age-matched WKY. These results indicate that NOx- production induced by mechanical stimulation was markedly reduced in 5-week-old SHR at the prehypertensive stage, which may have enhanced coronary autoregulation. An impaired nitric oxide production may precede the onset of hypertension in SHR.

Animals↗

PubMed2001

Altered expression of prostacyclin synthase in a subset of the thick ascending limb cells and mesangial cells in 5/6-nephrectomized rats.

The aim of this study was to evaluate the possible role of prostacyclin (PGl2) in the onset and development of hypertension and chronic renal failure in 5/6-nephrectomized rats (5/6NX). We measured the systolic blood pressure, 24-h urinary excretion levels of 6-keto-PGF1alpha, which was a stable metabolite of PGI2, and levels of PGI2 synthase (PCS) mRNA in the kidneys. Immunostaining for PCS in the kidneys was also evaluated. Systolic blood pressure was higher in 5/6NX than in sham-operated rats. The 24-h urinary excretion levels of 6-keto-PGF1alpha in 5/6NX at 1 week postsurgery were lower than in sham-operated rats. In renal morphology, tubulointerstitial injury was observed at 2 weeks postsurgery, and glomerulosclerosis at 4 weeks. Levels of PCS mRNA in 5/6NX decreased significantly at 1 and 2 weeks postsurgery compared with those in sham-operated rats, but at 8 weeks these levels showed a tendency to increase. Immunostaining for PCS was positive in a subset of the cortical thick ascending limb of Henle's loop cells, including macula densa in both groups. Moreover, in 5/6NX at 8 weeks postsurgery, mesangial cells also stained positive for PCS. In conclusion, our findings suggest that PCS might play an important role in mitigating glomerular hemodynamic changes associated with reduction of renal mass.

6-Ketoprostaglandin F1 alpha↗

PubMed2001

Non-invasive approach for diagnosing atrophic gastritis using the 13C-bicarbonate breath test.

The experiments presented here were done to evaluate whether the levels of CO2 in respiratory air during the 13C-bicarbonate breath test (13C-BBT) may be used as a marker of non-invasive diagnosis of the levels of atrophic gastritis. Twenty-eight patients with chronic gastritis and five healthy volunteers were enrolled in the study. Moreover, experimental gastritis was induced in rats by N-methy-N-nitro-N-nitrosoguanidine. In human, the levels of atrophic gastritis were evaluated from the vascular pattern of the gastric fornix. Total delta 13CO2 calculated from the 13C-BBT and the mucosal thickness ratio (MTR) were measured in rats with experimental gastritis. The levels of 13CO2 were significantly higher from patients with a vascular pattern at the fornix than in those without a vascular pattern (p<0.01). There was a good correlation between MTR and the levels of 13CO2, in rats with experimental gastritis (p<0.01). These findings indicate that the levels of 13CO2 during 13C-BBT reflect the levels of atrophic gastritis and show its clinical significance for non-invasive evaluation of atrophic gastritis. This has important clinical implications in selecting Helicobacter pylori-positive cases for therapy and follow-up.

Age Factors↗