No abstract

Helicobacter pylori CagA protein is considered a major virulence factor associated with gastric cancer. There are two major types of CagA proteins: the Western and East Asian CagA. The East Asian CagA-positive H. pylori infection is more closely associated with gastric cancer. The prevalence of gastric cancer is quite low in the Philippines, although Philippine populations are considered to originate from an East Asia source. This study investigates the characteristics of the cagA gene and CagA protein in Philippine H. pylori strains and compares them with previously characterized reference strains worldwide. The full-length cagA gene was sequenced from 19 Philippine isolates and phylogenetic relationships between the Philippine and 40 reference strains were analyzed. All Philippine strains examined were cagA positive, and 73.7% (14/19) strains were Western CagA-positive. The phylogenetic tree based on the deduced amino acid sequence of CagA indicated that the Philippine strains were classified into the two major groups of CagA protein: the Western and the East Asian group. These findings suggest that the modern Western influence may have resulted in more Western type H. pylori strains in the Philippines. Therefore, H. pylori-infected Filipinos can be considered to be at a low risk of developing gastric cancer.

An interventional case report is described of a patient with chronic postoperative endophthalmitis caused by the gram-negative aerobic rod Pseudomonas luteola. A 61-year-old developed slowly progressive blurring of vision, hypopyon, and vitritis following cataract surgery. Diagnostic vitrectomy and intraocular lens explantation were performed. The undiluted vitreous samples and explanted lens were analyzed. Aerobic cultures revealed moderate growth of P. luteola. The patient responded to intravitreal injections of piperacillin/tazobactam and oral trimethoprim/sulfamethoxasole. Best-corrected visual acuity improved from hand motions to 20/40. A repeat anterior chamber tap was negative. P. luteola may be a relatively nonvirulent cause of chronic endophthalmitis. Good visual outcomes may be obtained with appropriate therapy.

Helicobacter pylori infection in humans causes chronic gastritis, peptic ulcer disease and gastric carcinoma (1,8). It is well known that H. pylori secretes a potent cytotoxin (VacA), which induces cytoplasmic vacuolation in eukaryotic cells, resulting in cell death (2-5). We reported recently that VacA interacts with target cells by binding to receptor protein tyrosine phosphatase (RPTP) β, leading to vacuolation (7, 9). When VacA was added to AZ-521 cells, a human gastric adenocarcinoma cell line, which were cultured in EMEM supplemented with 10% FCS (Fetal Bovine Serum Sterile Filtered, EquitechBio, Inc.), we found that the extent of VacA-induced vacuolation was less than in medium without FCS. Therefore, we quantified VacA-induced vacuolation in AZ-521 cells with or without 10% FCS by neutral red uptake (9) and found that the high molecular weight factor in FCS inhibited Helicobacter pylori VacA-binding to its receptor, RPTPβ.The toxin-producing H. pylori strain ATCC49503 was used as the source of VacA for purification according to a modification of our published procedure (9). In brief, after growth of H. pylori in Brucella broth containing 0.1% β-cyclodextran at 37 C for 4 days with vigorous shaking in a controlled micro-aerophilic atmosphere of 10% O 2 and 10% CO 2 , VacA was precipitated from culture supernatant with 50% saturated ammonium sulfate and purified by VacA affinity column, which was coupled with anti-VacA specific IgG antibody and equilibrated with RX buffer (10 mM KCl, 0.3 mM NaCl, 0.35 mM MgCl 2 , and 0.125 mM EGTA in 1 mM HEPES, pH 7.3). After washing the column with RX buffer, VacA were eluted with 50 mM glysine-HCl buffer, pH 1, and then neutralized with 1 M Tris. After gel filtration by Superose 6HR 10/30 column with in TBS buffer (10 mM Tris-HCl buffer, pH 7.5, containing 50 mM NaCl), purified VacA was concentrated and stored (200 µg/ml). VacA concentration was determined by a Beads ELISA method (6). As shown in Fig. 1A, AZ-521 cells exposed to VacA for 4 hr with 10% FCS showed less vacuolation activity than cells incubated in media without FCS.To determine how FCS inhibits cell vacuolation, we Editor-Communicated Paper High Molecular Weight Factor in FCS Inhibits

Objective The predominant vacA genotype among Filipino patients has yet to be determined. This study aims to determine these common vacA genotypes via Polymerase Chain Reaction detectin using specific primers for each possible genotypes. Materials and methods DNA was obtained from 48 paraffin embedded gastrointestinal tissues from 31 patients of St. Lukeîs Medical Center from 1998 to 1999. Twenty‐three (23) patients were diagnosed with chronic active gastritis; 5 with chronic gastritis; one with chronic ulcer; and 2 with gasto‐intestinal cancer. Results From the PCR results, the signal sequence allele having the highest number among the samples was s1b (35%) while m2 was the common midregion type (42%). Among 12 samples completely genotypes, s1bm2 was most prevalent (50%). One samples from a cancer patient had multiple genotypes (s1am1, s1am2,s1bm1, s1bm2) Conclusion The vacA genotypes s1bm2 is the common genotype detected among the gastric biopsy samples obtained from Filipino patients.