Is antimicrobial susceptibility testing necessary before second-line treatment for Helicobacter pylori infection?

BACKGROUND

An antimicrobial susceptibility test for Helicobacter pylori before second-line treatment is often performed, although whether the test is truly necessary remains unknown.

PATIENTS AND METHODS

Eighty-two patients with H. pylori infection for whom first-line treatment with a 1-week proton pump inhibitor/amoxicillin-clarithromycin (AC) regimen had failed were randomly assigned to two groups: those having or not having the susceptibility test before re-treatment. The cure rates for these two groups were compared.

RESULTS

Five of the 82 patients were excluded from the analysis. For 38 patients in the susceptibility-test group, we used what we considered the best regimen based on susceptibility testing: 10 patients [no resistance to clarithromycin (CAM)] received the lansoprazole-amoxicillin-clarithromycin regimen, 22 patients [19 CAM resistant, metronidazole (MNZ) susceptible; three failure of culture] were given the lansoprazole-amoxicillin-metronidazole (LAM) regimen, and six patients (both MNZ and CAM resistant) received dual therapy with omeprazole (OPZ) and amoxicillin (AMOX) in which the OPZ dose was determined by the CYP2C19 gene polymorphism. For 39 patients in the group with no susceptibility testing, LAM regimens were prescribed. The intention-to-treat (ITT)-based cure rates in the groups with and without susceptibility testing were 81.6% (95% confidence interval; 66-92%) and 92.4% (79-98%), respectively, and there was no significant difference between these two groups.

CONCLUSION

Susceptibility testing is not necessarily required before second-line therapy if the first-line treatment has been performed using proton pump inhibitor/AC regimens.

Alteration of histological gastritis after cure of Helicobacter pylori infection

BACKGROUND

It is still disputed whether gastric atrophy or intestinal metaplasia improves after the cure of Helicobacter pylori infection.

AIM

To clarify the histological changes after the cure of H. pylori infection through a literature survey.

METHODS

Fifty-one selected reports from 1066 relevant articles were reviewed. The extracted data were pooled according to histological parameters of gastritis based on the (updated) Sydney system.

RESULTS

Activity improved more rapidly than inflammation. Eleven of 25 reports described significant improvement of atrophy. Atrophy was not improved in one of four studies with a large sample size (> 100 samples) and in two of five studies with a long follow-up period (> 12 months), suggesting that disagreement between the studies was not totally due to sample size or follow-up period. Methodological flaws, such as patient selection, and statistical analysis based on the assumption that atrophy improves continuously and generally in all patients might be responsible for the inconsistent results. Four of 28 studies described significant improvement of intestinal metaplasia [corrected].

CONCLUSIONS

Activity and inflammation were improved after the cure of H. pylori infection. Atrophy did not improve generally among all patients, but improved in certain patients. Improvement of intestinal metaplasia was difficult to analyse due to methodological problems including statistical power.

Localization of bradykinin B(2) receptor in the follicles of porcine ovary and increased expression of matrix metalloproteinase-3 and -20 in cultured granulosa cells by bradykinin treatment

We have recently shown that not only bradykinin, but also all components for the production of bradykinin, can be detected within the follicle of porcine ovaries. To elucidate the relevance of the intrafollicular bradykinin-producing system to its physiological role, we investigated the distribution of bradykinin receptor (B(2)R) mRNA and the protein in porcine ovaries. A cDNA encoding porcine B(2)R was first cloned from a porcine uterus cDNA library. The receptor mRNA was scarcely detected in the ovary by Northern blot analysis. Polymerase chain reaction analysis with total RNAs isolated from the ovary and from granulosa cells of small and large follicles demonstrated the ovarian expression of B(2)R mRNA. The B(2)R protein was detected by Western blot analysis in extracts of isolated granulosa cells. In situ hybridization of B(2)R mRNA and immunohistochemical analysis of the protein revealed that the receptor is expressed in the theca and granulosa cells of all growing follicles. The effect of bradykinin on the expression of some matrix metalloproteinase (MMP) genes was examined using isolated granulosa cells. Bradykinin treatment induced MMP-3 and MMP-20 gene expression to an extreme degree. The expression of MT1-MMP was also affected by bradykinin treatment. These results suggest that MMPs play a role in follicle rupture during ovulation. The present study provides new information regarding the mechanisms of bradykinin-induced ovulation in porcine ovaries.

Strategy for retreatment of therapeutic failure of eradication of Helicobacter pylori infection

BACKGROUND AND AIM

A proton pump inhibitor (PPI)-based triple therapy consisting of a PPI, amoxicillin (A) and clarithromycin (C) or metronidazole (M) provides an eradication rate ranging from 80 to 90%. However, there have been few controlled studies with regard to the most effective regimen to re-treat patients after failure of the first-line therapy. Accordingly, we retrospectively reviewed our experiences and compared regimens with different combinations of antimicrobials to determine the optimal retreatment regimen.

METHODS

Out of 133 patients who had received second-line therapy after failure of first-line PPI/AC therapy, we selected, for review, patients who took the prescribed drugs for first-line therapy equal to, or more than 80%. As a result, data on 114 patients (83 males and 31 females; mean age 49.1 +/- 13.0 years; peptic ulcer n = 89; non-ulcer dyspepsia, n = 25) were eligible for evaluation. They had either repeated the PPI/AC regimen (n = 34; 5-14 days), or had been administered the PPI/AM regimen (n = 80; 10 days). The cure rates of the two regimens were compared.

RESULTS

The eradication rates for second-line therapy with the PPI/AC regimen versus the PPI/AM regimen were 52.9% (95% CI, 35-70) versus 81.3% (95% CI, 71-89) by intention-to-treat analysis (P < 0.01), and 62.1% (95% CI, 42-79) versus 91.4% (95% CI, 81-97) by per-protocol analysis (P < 0.01).

CONCLUSION

The eradication rate for the PPI/AM retreatment regimen was significantly higher than for the repeated PPI/AC regimen, suggesting that a 10-day PPI/AM regimen can be recommended as a retreatment regimen for patients who had first-line eradication therapy by PPI/AC regimens.

Strategy for retreatment of therapeutic failure of eradication of Helicobacter pylori infection

BACKGROUND AND AIM

A proton pump inhibitor (PPI)-based triple therapy consisting of a PPI, amoxicillin (A) and clarithromycin (C) or metronidazole (M) provides an eradication rate ranging from 80 to 90%. However, there have been few controlled studies with regard to the most effective regimen to re-treat patients after failure of the first-line therapy. Accordingly, we retrospectively reviewed our experiences and compared regimens with different combinations of antimicrobials to determine the optimal retreatment regimen.

METHODS

Out of 133 patients who had received second-line therapy after failure of first-line PPI/AC therapy, we selected, for review, patients who took the prescribed drugs for first-line therapy equal to, or more than 80%. As a result, data on 114 patients (83 males and 31 females; mean age 49.1 +/- 13.0 years; peptic ulcer n = 89; non-ulcer dyspepsia, n = 25) were eligible for evaluation. They had either repeated the PPI/AC regimen (n = 34; 5-14 days), or had been administered the PPI/AM regimen (n = 80; 10 days). The cure rates of the two regimens were compared.

RESULTS

The eradication rates for second-line therapy with the PPI/AC regimen versus the PPI/AM regimen were 52.9% (95% CI, 35-70) versus 81.3% (95% CI, 71-89) by intention-to-treat analysis (P < 0.01), and 62.1% (95% CI, 42-79) versus 91.4% (95% CI, 81-97) by per-protocol analysis (P < 0.01).

CONCLUSION

The eradication rate for the PPI/AM retreatment regimen was significantly higher than for the repeated PPI/AC regimen, suggesting that a 10-day PPI/AM regimen can be recommended as a retreatment regimen for patients who had first-line eradication therapy by PPI/AC regimens.

Expression and localization of transcripts of MT5-MMP and its related MMP in the ovary of the medaka fish Oryzias latipes

cDNA clones of MT5-matrix metalloproteinase (MT5-MMP) and a related protein (designated MT5-MMP-del) were isolated by screening the cDNA library and by 3'-rapid amplification of cDNA ends using an ovary RNA of the medaka fish Oryzias latipes. The MT5-MMP clone encodes a protein of 546 amino acids while the MT5-MMP-del clone encodes a protein of 431 amino acids. Compared with mammalian counterparts, the fish MT5-MMP and MT5-MMP-del both lack the signal peptide and a part of the prodomain. The fish MT5-MMP and MT5-MMP-del were different in that the latter did not have the stem/transmembrane/cytoplasmic domain. The two fish MMPs were expressed in the ovary, testis, brain, and intestine. In the ovary, MT5-MMP mRNA was expressed in the oocytes of small growing follicles. In contrast, MT5-MMP-del mRNA was found in the stromal interstitial cells. These results strongly suggest that a MT5-MMP/gelatinase A cascade may possibly operate in the process of spawning and/or other events associated with ovulated oocytes or fertilized eggs of the medaka fish.

Five-day proton pump inhibitor-based quadruple therapy regimen is more effective than 7-day triple therapy regimen for Helicobacter pylori infection

BACKGROUND

There have been no reports that describe whether 5-day quadruple therapy (rabeprazole + amoxicillin + clarithromycin + metronidazole; RACM) could substitute for standard 7-day triple therapy as a first-line therapy for Helicobacter pylori.

PATIENTS AND METHODS

This study was designed as a randomized prospective single centre study. A total of 160 H. pylori-positive patients who had not received therapy were given either a 5-day RACM regimen (n=80, rabeprazole 20 mg b.d., amoxicillin 750 mg b.d., clarithromycin 200 mg b.d. and metronidazole 250 mg b.d.) or a 7-day RAC regimen (n=80, rabeprazole 20 mg b.d., amoxicillin 750 mg b.d. and clarithromycin 200 mg b.d.). Cure of the infection was assessed by a (13)C urea breath test 1 month after the completion of therapy.

RESULTS

The eradication rates of the 5-day RACM regimen and the 7-day RAC regimen were 93% (95% CI: 84--97%) and 81% (95% CI: 71--89%) by intention-to-treat analysis, 94% (95% CI: 86--98%) and 83% (95% CI: 73--91%) by all-patients-treated analysis analysis and 95% (95% CI: 87--98%; P < 0.05) and 82% (95% CI: 72--90%) by per protocol analysis, respectively. No serious adverse effect was observed, and 99% of the patients reported complete compliance.

CONCLUSIONS

The cure rate of the 5-day RACM regimen was more effective than the 7-day RAC regimen, suggesting that this regimen could be preferable as a first-line therapy for H. pylori infection.

Comparison of the efficacy of 400mg and 800mg of clarithromycin used with lansoprazole and amoxicillin in eradication regimens for Helicobacter pylori infection in a Japanese population

We conducted a randomized prospective comparative study to determine whether a 1-week lansoprazole-amoxicillin-clarithromycin (LAC) regimen with 800 mg of clarithromycin a day was more effective such a regimen with 400 mg daily in the Japanese population. One hundred and seventy-five Helicobacter pylori-positive patients were randomly assigned to receive one of two different 7-day regimens, one with clarithromycin 400 mg (LAC 400 regimen) and the other with clarithromycin 800 mg (LAC 800 regimen). The cure rates for both regimens were similar, although adverse effects were significantly more frequent in the LAC 800 regimen, suggesting that 400 mg of clarithromycin may be sufficient in our patient population.

Insertion or deletion of a single residue in the strut sequence of Dictyostelium myosin II abolishes strong binding to actin

The strut loop, one of the three loops that connects the upper and lower 50K subdomains of myosin, plays a role as a "strut" to keep the relative disposition of the two subdomains. A single residue was either inserted into or deleted from this loop. The insertion or deletion mutation abolished the in vivo motor functions of myosin, as revealed by the fact that the mutant myosins did not complement the phenotypic defects of the myosin-null cells. In vitro studies of purified full-length myosins and their subfragment-1s (S1s) revealed that the insertion mutants virtually lost the strong binding to actin although their motor functions in the absence of actin remained almost normal, showing that only the hydrophobic actin-myosin association was selectively affected by the insertion mutations. Unlike the insertion mutants, the deletion mutant showed defects both in the strong-binding state and the rate-limiting step of ATPase cycle. These results indicate the functional importance of the strut loop in establishing the strong-binding state of myosin and thereby achieving successful power strokes.

ATP-induced transconformation of myosin revealed by determining three-dimensional positions of fluorophores from fluorescence energy transfer measurements

The method of fluorescence resonance energy transfer (FRET) is one of the most important techniques for measuring the distance between two fluorophores and for detecting the changes in protein structure under physiological conditions. The use of green fluorescent protein is also a powerful technology that has been used to elucidate dynamic molecular events. From these we have developed a novel method to determine the three-dimensional positions of fluorophores by combining the FRET data and other structural information available. Using this method, we could determine the ATP-induced changes of three-dimensional structure of truncated Dictyostelium myosin in solution. The myosin structure with ADP in solution was found to be similar to that of the crystal structure of MgADPBeFx-bound truncated Dictyostelium myosin (type I structure), whereas myosin with ATP in solution was similar to the crystal structure of MgAdPVi-bound one (type II structure). However, the crystal structure of MgADP-bound scallop myosin (type III structure) could not be explained by any of our FRET data under various conditions. This indicates that the type III crystal structure might represent a transient intermediate conformation that could not be detected using fluorescence energy transfer.

Expression of gelatinases A and B in the ovary of the medaka fish Oryzias latipes

We cloned cDNAs for gelatinase A and gelatinase B from an ovary cDNA library of the medaka fish Oryzias latipes. The gelatinase A clone encodes a protein of 657 amino acids, whereas the gelatinase B clone encodes a protein of 690 amino acids. Gelatinase A mRNA was expressed in the testis, ovary, intestine, heart, spleen and kidney of the animal. In contrast, gelatinase B mRNA was detected in the ovary. Localization of the respective mRNAs in the ovary was examined using in situ hybridization. Gelatinase A mRNA was found only in the oocytes of small and middle-sized follicles. In contrast, gelatinase B was expressed exclusively in follicular tissues that had ovulated. In situ zymographic analysis revealed that gelatinolytic activity, presumably due to matrix metalloproteinase activity, was detectable in the areas surrounding small and middle-sized follicles, interstitial stromal tissues and the cytoplasm of oocytes. Using extracts of the whole ovary and of ovulated oocytes, several gelatin-degrading enzymes, which probably represent the intermediate and active forms of medaka fish gelatinase A and gelatinase B, were detected by gelatin zymographic analysis. These results clearly indicate that gelatinase A and gelatinase B play a discrete role in the ovary of this lower vertebrate animal.

Addition of metronidazole to rabeprazole-amoxicillin-clarithromycin regimen for Helicobacter pylori infection provides an excellent cure rate with five-day therapy

BACKGROUND

New triple therapy for eradication of Helicobacter pylori based on a proton pump inhibitor (PPI) provides a cure rate of approximately 90% with few adverse effects. Recently, a PPI-based quadruple therapy, which consists of a PPI plus bismuth-based triple therapy for 7 days, has been studied, and a sufficient eradication rate has been achieved. However, a shorter duration results in improved compliance. In this study, newly developed short-term, simple twice-daily quadruple therapy consisting of rabeprazole, amoxicillin, clarithromycin, and metronidazole (RACM) was compared with a PPI-based triple-therapy regimen for eradication of H. pylori.

PATIENTS AND METHODS

This study was designed as a randomized open, prospective single-center study. Of a total of 105 H. pylori-positive patients, 55 received the RACM regimen for 5 days (rabeprazole, 10 mg bid; amoxicillin, 750 mg bid; clarithromycin, 200 mg bid; and metronidazole, 250 mg bid), and 50 received the RAC regimen for 5 days (rabeprazole, 10 mg bid; amoxicillin, 750 mg bid; and clarithromycin, 200 mg bid). Cure of the infection was assessed by HpSA (H. pylori stool antigen immunoassay) 1 month after completion of therapy.

RESULTS

The rates of eradication of H. pylori by RACM versus RAC were 94.5% (95% CI, 85-99) versus 80.0% (95% CI, 66-90) by intention-to-treat analysis; 98.1% (95% CI, 90-100) versus 87.0% (95% CI, 74-95) by all-patients-treated analysis; and 98.1% (95% CI, 90-100) versus 86.7% (95% CI, 73-95) by per-protocol analysis. No major adverse effects were reported, and 98.0% of patients reported complete compliance.

CONCLUSIONS

The simple twice-daily and short-term quadruple regimen for only 5 days provided an excellent eradication rate. Compliance with the regimen was high, and serious adverse effects were few. Therefore, the RACM regimen can be considered as safe and effective.

The incidence of reflux oesophagitis after cure of Helicobacter pylori in a Japanese population

AIM

To investigate the incidence of reflux oesophagitis after antibacterial therapy for Helicobacter pylori infection in our patient population.

METHODS

Subjects were 451 H. pylori-infected patients (primary symptom: peptic ulcer disease in 347, nonulcer dyspepsia in 100, and reflux oesophagitis in four): 11 of these patients had reflux oesophagitis on study entry. H. pylori infection was treated by a proton pump inhibitor/amoxycillin-clarithromycin regimen for either 7 or 14 days. Each patient was examined by endoscopy before treatment and more than 6 months after treatment to compare oesophageal findings. In addition, 227 patients were interviewed regarding reflux symptoms, using symptom questionnaires, before and more than 6 months after treatment.

RESULTS

Among 440 patients who did not have reflux oesophagitis prior to antibacterial treatment (340 peptic ulcer patients and 100 nonulcer dyspepsia patients), 23 patients whose infection was eradicated developed reflux oesophagitis (5.4%). The 11 patients who had reflux oesophagitis prior to treatment were all successfully cured of infection. Six of these patients showed no change in their oesophagitis, while the condition improved in three and worsened in two. Symptom scores improved in 34 of the 36 patients who reported reflux symptoms. Among 19 patients who showed persistent infection, only one developed reflux oesophagitis (5.2%), while none complained of newly developed symptoms following treatment.

CONCLUSIONS

Development of reflux oesophagitis after treatment of H. pylori infection was observed in a Japanese population. However, the incidence of this condition was comparable between those with persistent H. pylori infection and those in whom the infection was eradicated.

Usefulness of a novel enzyme immunoassay for the detection of Helicobacter pylori in feces

BACKGROUND

In this study we assessed the reliability of a newly developed enzyme immunoassay (HpSA) kit for detecting Helicobacter pylori antigen in stool.

METHODS

This study included 309 patients, 147 of whom were defined as positive and 162 as negative by the 13C-urea breath test, rapid urease test, and pathologic findings. From these patients fresh stool specimens were collected for HpSA.

RESULTS

When 0.100 was adopted as the cut-off value, in accordance with the manufacturer's recommendations, the sensitivity, specificity, and accuracy of the HpSA were 98.0%, 87.0%, and 92.2%, respectively. However, these values were much improved when a cut-off value of 0.300 was adopted, which was obtained with our receiver-operator characteristics curve; with this value the sensitivity, specificity, and accuracy of HpSA were 93.9%, 95.7%, and 94.8%, respectively.

CONCLUSION

These results indicate that HpSA is a highly reliable diagnostic method for H. pylori infection and is useful in confirming eradication.

Efficacy of reduced dosage of rabeprazole in PPI/AC therapy for Helicobacter pylori infection: comparison of 20 and 40 mg rabeprazole with 60 mg lansoprazole

Proton pump inhibitor (PPI)- based triple therapy has been a recent trend for treatment of Helicobacter pylori infection, with the PPI-amoxicillin-clarithromycin (PPI/AC) regimen being one of the most popular. We have reported the effectiveness of PPI/AC regimens in the Japanese population and have demonstrated that the effectiveness of 40 mg rabeprazole, a recently developed PPI, is similar to that of 40 mg of omeprazole and 60 mg of lansoprazole when used in combination with amoxicillin and clarithromycin. In this study, we focused on whether 20 mg of rabeprazole is effective in our patient population by comparing that dosage with 40 mg of rabeprazole and 60 mg of lansoprazole. In all, 308 H. pylori-infected patients [236 men and 72 women; age (mean +/- SEM) 49.3+/-0.6 years] with peptic ulcer disease (N = 270) or nonulcer dyspepsia (N = 38) were randomly assigned to one of three different PPI/AC regimens for seven days: LAC (N = 104), consisting of lansoprazole 30 mg twice a day, amoxicillin 500 mg three times a day, and clarithromycin 200 mg twice a day; RAC (N = 104), consisting of rabeprazole 20 mg twice a day, amoxicillin 500 mg three times a day, and clarithromycin 200 mg twice a day; and the R1/2AC regimen (N = 100), which included rabeprazole 10 mg twice a day, amoxicillin 500 mg three times a day, and clarithromycin 200 mg twice a day. Cure of the infection was determined by the [13C]urea breath test one month after completion of the treatment. Intention-to-treat based and per-protocol based cure rates for the LAC, RAC, and R1/2AC regimens were 82.7 (95% CI, 74-89) and 88.7% (81-94), 85.6 (77-92) and 89.8% (82-95), and 87.0 (79-93) and 89.7% (82-95), respectively. Although adverse effects were reported by 20.3% of the patients, these affected compliance in only five patients in the RAC and LAC regimens and none in the R1/2AC group. Overall complete compliance was achieved in 94.7% of interviewed patients. In conclusion, the effectiveness of the PPI/AC regimen with 20 mg of rabeprazole is comparable with and even safer than that of 40 mg of rabeprazole and 60 mg of lansoprazole in our patient population.

Impact of rabeprazole, a new proton pump inhibitor, in triple therapy for Helicobacter pylori infection-comparison with omeprazole and lansoprazole

BACKGROUND

A recent trend in curative therapy for Helicobacter pylori infection is the so-called triple therapy, which consists of a proton pump inhibitor (PPI) and two different antimicrobials. Various regimens employing this triple therapy have been reported. However, little is known about the effectiveness of rabeprazole, a recently developed proton pump inhibitor, when used in the triple therapy.

AIM

To validate its usefulness by comparing rabeprazole with omeprazole and lansoprazole, in combination with amoxycillin and clarithromycin.

PATIENTS AND METHODS

221 H. pylori-positive patients with peptic ulcer disease were randomized to receive one of three different proton pump inhibitor/amoxycillin-clarithromycin (PPI/AC) regimens for 7 days. (i) OAC regimen (n = 75): omeprazole 20 mg b.d., amoxycillin (AMOX) 500 mg t.d.s. and clarithromycin (CAM) 200 mg b.d.; (ii) LAC regimen (n = 74): lansoprazole 30 mg b.d. , AMOX 500 mg t.d.s. and CAM 200 mg b.d.; and (iii) RAC regimen (n = 72): rabeprazole 20 mg b.d., AMOX 500 mg t.d.s. and CAM 200 mg b.d. Cure of the infection was determined by the 13C urea breath test 1 month after completion of the treatment.

RESULTS

Intention-to-treat based cure rates for OAC, LAC and RAC regimens were 85% (95% CI, 75-92), 84% (95%, CI 73-91) and 88% (95% CI, 78-94), respectively, and per protocol based cure rates of these regimens were 88% (95% CI, 78-94), 91% (95%, CI 82-99) and 93% (95% CI, 84-98), respectively. Adverse effects in the entire study population, which included diarrhoea, glossitis or skin rash, were reported by 15% of the patients, and complete compliance was achieved in 95% of these patients.

CONCLUSION

1-week proton pump inhibitor/AC regimens for H. pylori infection were effective in the Japanese population. Rabeprazole can be considered as equivalent to omeprazole and lansoprazole in the PPI/AC triple therapy.

Thermally reversible xyloglucan gels as vehicles for oral drug delivery

The potential, as sustained release vehicles, of gels formed in situ following the oral administration of dilute aqueous solutions of a xyloglucan polysaccharide derived from tamarind seed has been assessed by in vitro and in vivo studies. Aqueous solutions of xyloglucan that had been partially degraded by beta-galactosidase to eliminate 44% of galactose residues formed rigid gels at concentrations of 1.0 and 1.5% w/w at 37 degrees C. The in vitro release of indomethacin and diltiazem from the enzyme-degraded xyloglucan gels followed root-time kinetics over a period of 5 h at 37 degrees C at pH 6.8. Plasma concentrations of indomethacin and diltiazem, after oral administration to rats of chilled 1% w/w aqueous solutions of the enzyme-degraded xyloglucan containing dissolved drug, and a suspension of indomethacin of the same concentration were compared. Constant indomethacin plasma concentrations were noted from both formulations after 2 h and were maintained over a period of at least 7 h. Bioavailability of indomethacin from xyloglucan gels formed in situ was increased approximately threefold compared with that from the suspension. The results of this study suggest the potential of the enzyme-degraded xyloglucan gels as vehicles for oral delivery of drugs.

Efficacy of 1 week omeprazole or lansoprazole-amoxycillin-clarithromycin therapy for Helicobacter pylori infection in the Japanese population

BACKGROUND

The effectiveness of curative therapy for Helicobacter pylori may vary according to the geographic region and patient population, thus the efficacy of each treatment regimen should be determined according to the specific patient population. However, there is no literature available concerning the efficacy of 1 week omeprazole-amoxycillin-clarithromycin (OAC) regimens for the cure of H. pylori infection in Japan.

METHODS

Helicobacter pylori-positive patients (224) with peptic ulcer disease or non-ulcer dyspepsia were randomized to receive one of three different omeprazole or lansoprazole-amoxycillin-clarithromycin (PPI/AC) regimens for 7 days: (1) OAC 20 regimen (n = 76), omeprazole (OPZ) 20 mg daily, amoxycillin (AMOX) 500 mg t.d.s. and clarithromycin (CAM) 200 mg b.d.; (2) LAC 30 regimen (n = 73), Lansoprazole (LPZ) 30 mg daily, AMOX 500 mg t.d.s. and CAM 200 mg b.d.; and (3) OPZ 40 regimen (n = 75), OPZ 20 b.d., AMOX 500 mg t.d.s. and CAM 200 mg b.d. Cure of the infection was determined by the [13C]-urea breath test, 1 month after completion of the treatment.

RESULTS

Intention-to-treat based cure rates for OAC 20, LAC 30 and OAC 40 regimens were 75.0% (95% CI, 64-84%), 82.2% (95%, CI 72-90), and 80.0% (95% CI, 69-88), respectively and per-protocol based cure rates of these regimens were 79.2% (95% CI, 68-88%), 83.3% (95%, CI 73-91), and 83.1% (95% CI, 72-91%), respectively. Adverse effects, which included diarrhoea, glossitis or skin rash, were reported by 26.1% of the patients. However, these were mild and did not affect compliance.

CONCLUSION

One week PPI/AC regimens for H. pylori infection with smaller proton pump inhibitors and antimicrobial dosages compared to regimens used in Western countries were revealed to provide sufficient cure rate (more than 80% by ITT analysis) with mild adverse effects in the Japanese population.

[13C]-urea breath test for assessment of cure of Helicobacter pylori infection at 1 month after treatment

Although the [13C]-urea breath test has been reported to provide high specificity and sensitivity, its reliability in determination of cure, including when and how the assessment of cure is made, is not fully established. Here we evaluate the reliability of judgment of cure after 1 month of therapy using the [13C]-urea breath test, including the appropriate time to assess its cure. Our subjects were 199 H. pylori-infected patients (144 men and 55 women; 50.5+/-0.76 years) who underwent cure therapy, took the breath test at 1 month, and underwent both the breath test and invasive tests using endoscopy at 6 months after completion of therapy. Accuracy of the breath test in judgment of cure at 1 month was investigated by comparing the results at 1 month with those at 6 months when cut-off value of the breath test was set at 5 per thousand. Chronologic alterations of the delta13C value were also analyzed in cured patients who underwent the breath test at 1, 3, and 6 months. In 167 (94.9%) of 176 patients whose breath test values were less than 5 per thousand, cure was reconfirmed at 6 months. In 14 (60.9%) of 23 patients whose values were greater than 5 per thousand, cure was demonstrated at 6 months. The mean delta13C values of 33 cured patients who took the breath test at 1 month and repeated the breath test at 3 and 6 months for any reasons were 4.14+/-0.74 per thousand, 2.02+/-0.23 per thousand, and 1.72+/-0.19 per thousand, respectively, and the value at 3 months was significantly smaller than that at 1 month. The reliability of assessment of cure by only the breath test at 1 month was sufficiently high (94.9%) once the patients were judged to be cured. However, because the breath test at 1 month yielded a high false-positive rate and the breath test values at 3 and 6 months were similar, evaluation of cure of H. pylori infection by the [13C]-urea breath test should preferably be done at 3 months after treatment to minimize false-positive results, or the concept of a borderline group should be established for patients with positive but relatively high delta13C values (5-10 per thousand) who repeated the breath test 3 months after treatment.

Swing of the lever arm of a myosin motor at the isomerization and phosphate-release steps

In muscle, the myosin head ('crossbridge') performs the 'working stroke', in which ATP is hydrolysed to generate the sliding of actin and myosin filaments. The myosin head consists of a globular motor domain and a long lever-arm domain. The 'lever-arm hypothesis' predicts that during the working stroke, the lever-arm domain tilts against the motor domain, which is bound to actin in a fixed orientation. To detect this working stroke in operation, we constructed fusion proteins by connecting Aequorea victoria green fluorescent protein and blue fluorescent protein to the amino and carboxyl termini of the motor domain of myosin II of Dictyostelium discoideum, a soil amoeba, and measured the fluorescence resonance energy transfer between the two fluorescent proteins. We show here that the carboxy-terminal fluorophore swings at the isomerization step of the ATP hydrolysis cycle, and then swings back at the subsequent step in which inorganic phosphate is released, thereby mimicking the swing of the lever arm. The swing at the phosphate-release step may correspond to the working stroke, and the swing at the isomerization step to the recovery stroke.

Usefulness of the [13C]-urea breath test for detection of Helicobacter pylori infection in fasting patients

Most of the reported [13C]-urea breath test procedures use a test meal, which is believed to assist in the spread of the [13C]-urea solution into the entire stomach, as results without a test meal may mainly reflect urease activity in the antrum.Yet, procedures for the [13C]-urea breath test and interpretation of the obtained 13C excess value have not been well established. We carried out the present study to validate the usefulness of the [13C]-urea breath test in fasting subjects and to establish cut-off values. [13C]-Urea breath tests were performed on 258 Helicobacter pylori-positive and 151 -negative subjects (247 H. pylori positive and 26 negative prior to any H. pylori cure treatment and 125 H. pylori negative and 11 positive after undergoing H. pylori cure treatment). The breath test procedure was performed under the following conditions: an 8 h fast, mouth washing before and after dosing, administration of 100 mg [13C]-urea, collection of breath sample in a plastic bag, a baseline and a 20 min sampling point and subject in a sitting position. Delta-13C at the 20 min sampling point in H. pylori-positive and -negative subjects was 31.0+/-1.25 and 1.6+/-0.11%, respectively. Although the mean delta13C value was greatest in duodenal ulcer or ulcer scar patients, there were no significant differences among mean delta13C values in the various diseases. From Receiver Operator Characteristic curves and calculation of accuracy of the test, a cut-off value of 5.0% is considered to be appropriate for diagnosis of H. pylori infection, which provides 96.7% specificity and 96.5% sensitivity, suggesting that the [13C]-urea breath test in the fasting state is as effective in detecting the presence of H. pylori as other reported methods.

Effectiveness of omeprazole-amoxicillin-clarithromycin (OAC) therapy for Helicobacter pylori infection in a Japanese population

BACKGROUND

Omeprazole or lansoprazole, amoxicillin, clarithromycin (PPI/AC) therapy has been reported to provide a high cure rate of H. pylori infection with few adverse effects. Effectiveness of H. pylori therapy may vary among different geographic regions and patient populations. However, there are few reports in Japan as to its effectiveness. We have, therefore, studied the effectiveness of H. pylori therapy in a large group of Japanese patients.

METHODS

For this study, 366 H. pylori-positive patients with peptic ulcer disease or non-ulcer dyspepsia (263 men and 103 women, mean age 48.5 years) were assigned to 6 groups, each receiving a different PPI/AC regimen. Group 1 received omeprazole (OPZ) 20 mg, amoxicillin (AMOX) 1500 mg, and clarithromycin (CAM) 400 mg; Group 2 OPZ 40 mg, AMOX 1500 mg, and CAM 400; and Group 3 OPZ 20 mg, AMOX 2000 mg, and CAM 600 mg daily for 14 days. The group treated with lansoprazole (LPZ) 30 mg, AMOX 1500 mg and CAM 400 mg was used for 14 days in Group 1L. OPZ 20 mg, AMOX 750 mg, and CAM 200 mg were given to Group 4 for 28 days and OPZ 20 mg, AMOX 1500 mg, CAM 400 mg was administered to Group 5 for 7 days. Cure of infection was assessed by 13C urea breath test one month after completion of therapy.

RESULTS

Cure rates calculated by excluding the patients who showed borderline value of 13C urea breath test (delta 13C value between 5 and 10% in Groups 1, 1L, 2, 3, 4, and 5 were 82.7% (95% CI; 74-90), 88.9% (76-96), 84.9% (72-93), 81.3% (67-91), 84.6% (72-93), and 85.1% (72-94) on an intention-to-treat basis, and 88% (80-94), 95.2% (84-99), 95.6% (85-99), 90.7% (78-97), 95.7% (85-99) and 88.9% (76-96) on a per-protocol basis, respectively. Adverse effects that affected compliance were observed in 10 of 237 patients on 14-day regiments, one of 47 on a 28-day regimen and one of 46 on a 7-day regimen.

CONCLUSION

Two weeks PPI/AC therapy is highly effective for cure of H. pylori infection in the Japanese population. The low dose one month regimen and the one week OAC regimen were also effective in our patient population.

Alanine scanning mutagenesis of the switch I region in the ATPase site of Dictyostelium discoideum myosin II

In order to determine the functional roles of the conserved sequence (NXNSSRFG) of the "switch I" loop (residues 233-240 in Dictyostelium myosin II), alanine scanning mutagenesis was performed on Dictyostelium myosin II. N233A and S237A mutant myosins did not bind a fluorescent analog of ADP, mant-deoxyADP, at the low concentration range (micromolar and had low level of ATPase activities. They were nonmotile when examined by the in vitro motility assay. Dictyostelium cells expressing these myosins showed worse phenotypes than that of myosin-null cells. In contrast to these mutant myosins, R238A myosin tightly bound mant-deoxyADP. However, the mutant had a defect in the ATP hydrolysis step and exhibited the lowest ATPase activities among the mutants examined here. The R238A myosin was nonmotile. R238C or R238H mutations, which mimic the Usher syndrome mutations, generated myosins with similar functional defects to those of the R238A mutation. Cells expressing the R238A myosin exhibited the phenotype similar to that of the myosin-null cells. N235A, S236A, F239A, and G240A myosins retained moderate levels of ATPase activities and could drive sliding of actin filaments at various speeds. Phenotypes of cells expressing them were very similar to that of the wild-type cells. Taken together, these results suggest that side chains of N233 and S237 may play essential roles in holding a nucleotide in the ATPase pocket and that R238 may play crucial roles in the ATP hydrolysis step, while those of the other residues in the switch I loop are not essential for the process.

Radiological retrospective study of gastric cancer in humans: two patterns of development in elevated type gastric cancer

A better understanding of the process of gastric cancer development would undoubtedly be helpful in diagnosis and treatment. However, there is little literature available concerning the natural history of elevated type gastric cancer in humans and this disease had not been systematically investigated. In this study the natural history of elevated type human gastric cancer was retrospectively investigated in 12 radiologically followed-up patients. The cases were divided into two groups according the whether obvious abnormal findings were absent (group A, n = 5) or present (group B, n = 7) at initial examination. Clinico-pathological features, including outcomes and DNA content of the tumours in both groups, were investigated and compared. Although the mean period between the initial and final examinations was significantly shorter in group A (19.6 +/- 11.7 months) than in group B (43.4 +/- 17.3 months), tumour size was significantly larger in group A (5.5 +/- 2.5 cm) than in group B (2.4 +/- 2.5 cm). Furthermore, group A showed deeper neoplastic cell invasion and worse outcomes. The DNA content of two cases in group A and four cases in group B was examined. One case in group A showed and aneuploid pattern, while all of those in group B showed a diploid pattern. These results indicate that the tumours in group A grew much faster than those in group B, which suggests the presence of two different patterns of development in elevated type gastric cancer.

Effect of fasting subjects' posture on 13C-urea breath test for detection of Helicobacter pylori infection

BACKGROUND

Although many factors that may affect the 13C-urea value have been verified, no literature is available regarding the effect of the posture of the patient on the shape of the delta 13C excretion curve. In an effort to contribute to the development of a simple and standard procedure for the 13C-urea breath test, we investigated whether either the posture of the patient during the procedure or the mouthwash after dosing affects the shape of the delta 13C excretion curve.

MATERIALS AND METHODS

Seventy-two Helicobacter pylori-infected subjects were divided into four groups according to the position during procedure and the mouthwash after dosing: group A, in the supine position with mouthwash; group B, in the sitting position with mouthwash; group C, changed position by rolling with mouthwash; and group D, changed position (as did group C) without mouthwash. Absolute values of delta 13C at each sampling point were compared in the four groups.

RESULTS

delta 13C values in group A gradually increased until the 15-minute point; those in group B were almost stable from 5 to 30 minutes, and those in group C peaked at the 5-minute point, then decreased until 30 minutes, the values becoming similar at the 20-minute point. Significant differences were seen between groups A, B, C, and D at the 5- and 10-minute points.

CONCLUSION

These results suggest that posture and mouthwash affect delta 13C value at the 5- and 10-minute points. Sampling at 20 (maybe 15 or 30) minutes for fasting patients in a sitting position is considered to be appropriate for detection of H. pylori infection in a standard two-sampling-point 13C-urea breath test.

Multiple early esophageal cancers arising from Barrett's esophagus, and a review of cases of early adenocarcinoma in Barrett's esophagus in Japan

A case of early esophageal adenocarcinoma arising in Barrett's esophagus is reported. Many cases of Barrett's esophagus, which is considered a premalignant condition, have been reported in Western countries, but few cases have been reported in Japan. The patient, a 53-year-old man with nausea and vomiting, was a drinker (four glasses wine/day for about 30 years), but did not smoke. He had had a hiatal hernia of the esophagus. Since endoscopic biopsies demonstrated an early adenocarcinoma in Barrett's esophagus, subtotal esophagectomy was performed. In the resected esophageal material, Barrett's esophagus was seen to extend for 12 cm. In addition to the cancer detected preoperatively as a 0-IIc lesion (1.5 cm in diameter), a 0-IIb lesion (1.5 cm in diameter) was also detected in the postoperative survey. Both lesions were well differentiated adenocarcinoma that had invaded only into the lamina propria mucosa. The 23 cases of early adenocarcinoma in Barrett's esophagus that have been reported in Japan were reviewed, and it was learned that the present case is the second of multiple early cancer arising in Barrett's esophagus so far reported in Japan.

Modulation of actin filament sliding by mutations of the SH2 cysteine in Dictyostelium myosin II

The cysteine residue called SH2 in the skeletal myosin heavy chain is conserved among various species. Cys 678 in Dictyostelium myosin II is equivalent to SH2 in skeletal myosin. Using the Dictyostelium myosin II heavy chain gene, SH2 was mutated to Gly, Ala, Ser, or Thr. These mutant myosins were expressed in Dictyostelium myosin-null cells. To investigate how these mutations affect the motor functions of myosin, we examined the phenotypes of the transformed cells. We also purified the mutant myosins, and characterized them by measuring the actin-activated MgATPase activity, sliding velocity of actin filaments and force level. All of these mutant myosins complemented the myosin-specific defects of the myosin-null cells. Consistent with these observed phenotypes, all of the purified mutant myosins retained similar actin-activated MgATPase activities and force levels to those of the wild-type myosin (WT). However, the sliding velocities of actin filaments were significantly different (WT > or = Ser > Ala >> Thr > Gly). In particular, the Gly and Thr mutants exhibited a striking decrease in velocity, while the Ser mutant exhibited velocity comparable to that of the wild-type myosin. Thus, mutations of SH2 resulted in uncoupling of ATP hydrolysis and the sliding.

Evaluation of ethanol on gastric epithelial restoration in vitro

Ethanol exerts damaging effects on gastric mucosa and delays ulcer healing. To investigate the effect of ethanol on the wound repairing process, we used a wound repair model using primary cultured gastric mucosal cells. A confluent monolayer gastric mucosal cell sheet consisting mainly of mucous cells was wounded to make a cell-free area of constant size. Cell-free area was restored with time after wounding and monitored every 12 hr using a computer image analyzer to observe epithelial cell restoration quantitatively in the presence and absence of ethanol (2.0%). It was found that, although the control wound was completely repaired in 36 to 48 hr, the group treated with 2.0% ethanol showed a significant delay of repair. In the control, 5-bromodeoxyuridine-positive cells appeared around the wound in 24 to 36 hr. In contrast, the group treated with 2.0% ethanol showed no 5-bromodeoxyuridine-positive cells during the experiment. In conclusion, 2.0% ethanol retarded the repair of gastric mucosal restoration by inhibiting the initial gastric cell migration, followed by inhibition of proliferation of cells.

Diagnosis of gastric adenoma versus early gastric cancer by bromodeoxyuridine immunohistochemistry from gastric biopsy specimen

Differentiation between gastric adenomas and type IIa early gastric cancer by macroscopic and histologic examinations is often difficult. This study has shown that there are differences in the distribution of S-phase cells in these two types of tumour, and these differences can be exploited to differentiate between them. The distribution of S-phase cells was assessed by Bromodeoxyuridine (BrdU) immunohistochemistry using an in vitro BrdU-labelling method. Biopsy specimens were obtained from 27 lesions (12 adenomas and 15 type IIa early gastric cancers), and the distributions of BrdU-labelled cells in the tumour thickness as well as in the superficial layer of the tumour were determined. Significant difference was seen in the labelling of the two tumour types with regard to both these parameters. Using the criteria of BrdU immunohistochemistry, the accuracy of differentiation between gastric adenomas and cancers was 88.9%. Therefore, it is concluded in this study that in vitro BrdU labelling is a useful method of diagnosing gastric adenomas and cancers.