Hsiang-Yao Shih

Diagnosis of Helicobacter pylori infection: Current options and developments.

Accurate diagnosis of Helicobacter pylori (H. pylori) infection is a crucial part in the effective management of many gastroduodenal diseases. Several invasive and non-invasive diagnostic tests are available for the detection of H. pylori and each test has its usefulness and limitations in different clinical situations. Although none can be considered as a single gold standard in clinical practice, several techniques have been developed to give the more reliable results. Invasive tests are performed via endoscopic biopsy specimens and these tests include histology, culture, rapid urease test as well as molecular methods. Developments of endoscopic equipment also contribute to the real-time diagnosis of H. pylori during endoscopy. Urea breathing test and stool antigen test are most widely used non-invasive tests, whereas serology is useful in screening and epidemiological studies. Molecular methods have been used in variable specimens other than gastric mucosa. More than detection of H. pylori infection, several tests are introduced into the evaluation of virulence factors and antibiotic sensitivity of H. pylori, as well as screening precancerous lesions and gastric cancer. The aim of this article is to review the current options and novel developments of diagnostic tests and their applications in different clinical conditions or for specific purposes.

CYP2C19 polymorphism influences Helicobacter pylori eradication

The known factors that have contributed to the decline of Helicobacter pylori (H. pylori) eradication rate include antibiotic resistance, poor compliance, high gastric acidity, high bacterial load, and cytochrome P450 2C19 (CYP2C19) polymorphism. Proton pump inhibitor (PPI) is important in the eradication regimen. The principal enzyme implicated in the metabolism of PPIs is CYP2C19. The effects of PPI depend on metabolic enzyme, cytochrome P450 enzymes, and CYP2C19 with genetic differences in the activity of this enzyme (the homozygous EM, heterozygous EM (HetEM), and poor metabolizer). The frequency of the CYP2C19 polymorphism is highly varied among different ethnic populations. The CYP2C19 genotype is a cardinal factor of H. pylori eradication in patients taking omeprazole- based or lansoprazole-based triple therapies. In contrast, the CYP2C19 polymorphism has no significant effect on the rabeprazole-based or esomeprazole-based triple therapies. The efficacy of levofloxacin-based rescue triple therapy might be also affected by the CYP2C19 polymorphism, but CYP2C19 genotypes did not show obvious impact on other levofloxacin-based rescue therapies. Choice of different PPIs and/or increasing doses of PPIs should be individualized based on the pharmacogenetics background of each patient and pharmacological profile of each drug. Other possible factors influencing gastric acid secretion (e.g., IL-1β- 511 polymorphism) would be also under consideration.

Low effect-site concentration of propofol target-controlled infusion reduces the risk of hypotension during endoscopy in a Taiwanese population.

Target‐controlled infusion (TCI) of propofol is an effective way of delivering propofol during endoscopy. However, the ideal effect‐site concentration (Ce) of propofol has not yet been defined in an Asian population. This study aimed to determine the ideal Ce of propofol in painless gastrointestinal endoscopy in a Taiwanese population.

Helicobacter pylori Infection and Anemia in Taiwanese Adults

Background. Chronic Helicobacter pylori infection and iron-deficiency anemia (IDA) are common in adults. Although the most common causes of IDA usually arise from the gastrointestinal tract, the association between chronic Helicobacter pylori infection and anemia remains unclear. Aim. To evaluate the association of chronic Helicobacter pylori infection and IDA. Materials and Methods. We enrolled 882 patients from January 2010 to April 2013. The status of Helicobacter pylori (H.p) infection was confirmed and blood samples from the same participants were taken on the same day to check the level of hemoglobin, serum iron, ferritin, and total iron-binding capacity (TIBC). Results. No significant difference was noted from the demographic data. The average level of hemoglobin (Hb) was not different between negative and positive groups, pos 13.57 g/dL versus neg 13.65 g/dL (P = 0.699). Although the levels of serum IDA related parameters were expected in positive group (lower serum iron and ferritin and higher TIBC) these differences did not reach statistical significance (P = 0.824 for iron, P = 0.360 for ferritin, and P = 0.252 for TIBC). Conclusion. Chronic Helicobacter pylori infection is not attributed to IDA. The levels of hemoglobin, serum iron and ferritin, and TIBC remain unaffected after chronic H.p infection. Large-scale clinical studies are needed to prove the association.

A Rapid and Accurate Method to Evaluate Helicobacter pylori Infection, Clarithromycin Resistance, and CYP2C19 Genotypes Simultaneously From Gastric Juice.

AbstractBecause Helicobacter pylori (H pylori) would cause carcinogenesis of the stomach, we need sufficient information for deciding on an appropriate strategy of eradication. Many factors affect the efficacy of eradication including antimicrobial resistance (especially clarithromycin resistance) and CYP2C19 polymorphism. This study was to survey the efficiency of gastric juice for detecting H pylori infection, clarithromycin resistance, and CYP2C19 polymorphism.The specimens of gastric juice were collected from all patients while receiving gastroscopy. DNA was extracted from gastric juice and then urease A and cag A were amplified by polymerase chain reaction (PCR) for detecting the existence of H pylori. By PCR-restriction fragment length polymorphism (PCR-RFLP), the 23S rRNA of H pylori and CYP2C19 genotypes of host were examined respectively. During endoscopy examination, biopsy-based specimens were also collected for rapid urease test, culture, and histology. The blood samples were also collected for analysis of CYP2C19 genotypes. We compared the results of gastric juice tests with the results of traditional clinical tests.When compared with the results from traditional clinical tests, our results from gastric juice showed that the sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV), and accuracy to detect H pylori infection were 92.1% (105/114), 92.9% (143/154), 90.5% (105/116), 94.1% (143/152), and 92.5% (248/268), respectively. The SEN, SPE, PPV, and NPV to detect clarithromycin resistance were 97.3% (36/37), 91.5% (43/47), 90.0% (36/40), and 97.7% (43/44), respectively. By using PCR-RFLP, the consistency of human CYP2C19 gene polymorphism from blood samples and gastric juice was as high as 94.9% (149/157).The manipulated gastric juice is actually an effective diagnostic sample for evaluation of H pylori existence, clarithromycin resistance, and host CYP2C19 polymorphism.

Comparison of Second-Line Quadruple Therapies with or without Bismuth for Helicobacter pylori Infection

The bismuth-based quadruple regimen has been applied in Helicobacter pylori rescue therapy worldwide. The non-bismuth-based quadruple therapy or “concomitant therapy” is an alternative option in first-line eradication but has not been used in second-line therapy. Discovering a valid regimen for rescue therapy in bismuth-unavailable countries is important. We conducted a randomized controlled trial to compare the efficacies of the standard quadruple therapy and a modified concomitant regimen. One hundred and twenty-four patients were randomly assigned into two groups: RBTM (rabeprozole 20 mg bid., bismuth subcitrate 120 mg qid, tetracycline 500 mg qid, and metronidazole 250 mg qid) and RATM (rabeprozole 20 mg bid., amoxicillin 1 g bid., tetracycline 500 mg qid, and metronidazole 250 mg qid) for 10 days. The eradication rate of the RBTM and RATM regimen was 92.1% and 90.2%, respectively, in intention-to-treat analysis. Patients in both groups had good compliance (~96%). The overall incidence of adverse events was higher in the RATM group (42.6% versus 22.2%, P = 0.02), but only seven patients (11.5%) experienced grades 2-3 events. In conclusion, both regimens had good efficacy, compliance, and acceptable side effects. The 10-day RATM treatment could be an alternative rescue therapy in bismuth-unavailable countries.

Glutaraldehyde-induced colitis: case reports and literature review.

Glutaraldehyde‐induced colitis is an uncommon colitis in clinical practice. Because the involvement of colonic segment is determined by the endoscopic part where glutaraldehyde remains, a recent history of endoscopy and a demarcated involvement of colonic segment are the most characteristic signs of glutaraldehyde‐induced colitis. The typical clinical scenario is acute onset of lower abdominal pain, fever, and bloody stool. Laboratory data usually show leukocytosis and elevated C‐reactive protein. The endoscopic pictures of involved segments are compatible with acute colitis, including hyperemic, edematous, with or without multiple erosions. Acute ischemic colitis and infectious colitis should be differentiated at the outset of the disease. Stool pathogen tests are usually negative. Parenteral empiric antibiotic may be considered if severe transmural edema of the involved segment is observed in computed tomography. Conservative treatment, including bowel rest and parenteral hydration, is able to stabilize the condition in a week. Herein, we present two cases of acute proctocolitis caused by glutaraldehyde after uneventful colonoscopy.

The effect of Helicobacter pylori eradication on the levels of essential trace elements.

Objective. This study was designed to compare the effect of Helicobacter pylori (H. pylori) infection treatment on serum zinc, copper, and selenium levels. Patients and Methods. We measured the serum zinc, copper, and selenium levels in H. pylori-positive and H. pylori-negative patients. We also evaluated the serum levels of these trace elements after H. pylori eradication. These serum copper, zinc, and selenium levels were determined by inductively coupled plasma mass spectrometry. Results. Sixty-three H. pylori-positive patients and thirty H. pylori-negative patients were studied. Serum copper, zinc, and selenium levels had no significant difference between H. pylori-positive and H. pylori-negative groups. There were 49 patients with successful H. pylori eradication. The serum selenium levels were lower after successful H. pylori eradication, but not significantly (P = 0.06). There were 14 patients with failed H. pylori eradication. In this failed group, the serum selenium level after H. pylori eradication therapy was significantly lower than that before H. pylori eradication therapy (P < 0.05). The serum zinc and copper levels had no significant difference between before and after H. pylori eradication therapies. Conclusion. H pylori eradication regimen appears to influence the serum selenium concentration (IRB number: KMUH-IRB-20120327).

Comparison between Single-Dose Esomeprazole- and Pantoprazole-Based Triple Therapy on the Effectiveness for Helicobacter pylori Eradication in Taiwanese Population

Background and Study Aims. To compare the effectiveness of two regimens, single-dose esomeprazole- and pantoprazole-based triple therapy, for Helicobacter pylori (H. pylori) eradication. Patients and Methods. A total of 453 patients were enrolled for H. pylori eradication. They were randomly assigned to either EAC group (Esomeprazole 40 mg once daily, Amoxicillin 1 g twice daily, Clarithromycin 500 mg twice daily for 7 days) or PAC group (Pantoprazole 40 mg twice daily, Amoxicillin 1 g twice daily, Clarithromycin 500 mg twice daily for 7 days). Follow-up endoscopy or urea breath test was scheduled 12–16 weeks after the eradication to evaluate the therapeutic response. Results. Higher eradication rate in EAC group than PAC group was shown by intention-to-treat analysis (EAC 72% versus PAC 55%, P < 0.05) and per-protocol analysis (EAC 91% versus PAC 72%, P < 0.05). The incidence of adverse effects (EAC 19% versus PAC 17%, P = 0.712) and the compliance (EAC 87% versus PAC 91%, P = 0.083) were comparable between these 2 groups. Conclusions. Single-dose esomeprazole-based triple therapy is effective for H. pylori eradication.

Insights into the management of gastric antral vascular ectasia (watermelon stomach)

Gastric antral vascular ectasia (GAVE) is an uncommon but important cause of chronic gastrointestinal bleeding. It is often associated with systemic diseases such as autoimmune diseases, liver cirrhosis, chronic renal insufficiency and cardiovascular disease. The etiology of GAVE has not been fully explored and remains controversial. Diagnosis is mainly based on endoscopic presentation with flat or raised erythematous stripes radiating from the pylorus to the antrum and resembles a watermelon. Clinical presentation may range from iron-deficiency anemia secondary to occult blood loss, melena to hematemesis. In past decades, many therapeutic modalities including medical, endoscopic and surgical intervention have been introduced for GAVE treatment with variable efficacy. Herein, we review the efficacy and safety of these treatment options for GAVE.