Significance of Pseudomonas aeruginosa colonization of the gastrointestinal tract

OBJECTIVE: This study was conducted to determine the association between gastrointestinal (GI) colonization and the development of invasive Pseudomonas aeruginosa infections and risk factors for acquisition of P. aeruginosa colonization in gut. METHODS: All stool specimens sent for microbiological examination were cultured for P. aeruginosa search for three years. PATIENTS AND MATERIALS: P. aeruginosa had been isolated from stool of 207 patients for three years. Of the 207 patients, 87 patients were identified P. aeruginosa-colonized patients. RESULTS: Forty-five (52%) were exposed to previous invasive procedures and eighty-three (95%) were prescribed antibiotics before the isolation of P. aeruginosa. Fourteen distinctive P. aeruginosa infections were developed in 13 patients (15%). Infections associated with GI colonization included 4 pneumonia, 4 urinary tract infection, 3 skin infection, and 3 bacteremia. The age, gender, underlying diseases, previous invasive procedures, and the duration of hospitalization were not significant. Twelve (34%) patients were diagnosed with ileus and three (9%) were undergoing gastrostomy during the acquisition of P. aeruginosa colonization in gut. CONCLUSION: Gastrointestinal disorders, especially obstruction and surgical interventions, are also important for the acquisition of by P. aeruginosa, in the GI tract.     

Effect of ethanol on endothelin-1 release from gastric vasculature

The effects of ethanol on gastric vasculature in isolated vascularly perfused rabbit stomach was investigated. The isolated stomach was perfused with Krebs-Henseleit solution containing 3% dextran bubbled with 95% O₂ and 5% CO₂ at a rate of 12 ml/min. After mixture and perfusion of 10 mM to 400 mM of ethanol, perfusion pressure and endothelin-1 concentration in effluent from gastric vasculature were measured. Perfusion pressure and endothelin-1 concentration in effluent increased in a dose-dependent manner with increasing ethanol concentrations. In conclusion, the data suggest that ethanol may stimulate the release of endothelin from gastric vasculature and may cause gastric ischemia due to vasoconstriction resulting in acute gastric mucosal injury.     

Identification and expression of Fasciola gigantica thioredoxin

In the present study, a cDNA encoding Trx from F. gigantica (FgTrx) was cloned by polymerase chain reaction (PCR). The sequence of FgTrx, analyzed by BLAST, SignalP, and ClustralW programs, showed 315 bp of an open reading frame (ORF), 12 bp 5’UTR, 78 bp 3’UTR, and the putative FgTrx peptide comprising of 104 amino acids, with a molecular weight of 11.68 kDa, with the active site containing five amino acids (tryptophan, cysteine, glycine, proline, cysteine) with a conserved dithiol motif from the two cysteines, and pI 5.86. The peptide had no signal sequence; hence, it was not a secreted protein. The recombinant FgTrx was expressed in Escherichia coli BL21 (DE3) and used for production for a polyclonal antibody in rabbits (anti-rFgTrx). The FgTrx protein expression, estimated by indirect ELISA using the rabbit anti-rFgTrx as probe, showed high levels in eggs, 2- and 4-week-old juveniles, and adult parasite. In a functional test, the rFgTrx exhibited specific activity that could be suppressed by an inhibitor (PX12). When tested by immunoblotting and immunohistochemistry, rabbit anti-rFgTrx reacted with natural FgTrx at a molecular weight of 11.68 kDa from eggs, metacercariae, NEJ, 2- and 4-week-old juveniles, and adult F. gigantica. The FgTrx protein was distributed at high levels in the tegument of 2- and 4-week-old juveniles, and the tegument, parenchyma, eggs, and reproductive organs of adult parasites. FgTrx may be one of the major factors acting against oxidative stresses that can damage the parasite; hence, it could be considered as a novel vaccine or drug target.     

Two anatomically distinct niches regulate stem cell activity

The niche microenvironment controls stem cell number, fate, and behavior. The bone marrow, intestine, and skin are organs with highly regenerative potential, and all produce a large number of mature cells daily. Here, focusing on adult stem cells in these organs, we compare the structures and cellular components of their niches and the factors they produce. We then define the niche as a functional unit for stem cell regulation. For example, the niche possibly maintains quiescence and regulates fate in stem cells. Moreover, we discuss our hypothesis that many stem cell types are regulated by both specialized and nonspecialized niches, although hematopoietic stem cells, as an exception, are regulated by a nonspecialized niche only. The specialized niche is composed of 1 or a few types of cells lying on the basement membrane in the epithelium. The nonspecialized niche is composed of various types of cells widely distributed in mesenchymal tissues. We propose that the specialized niche plays a role in local regulation of stem cells, whereas the nonspecialized niche plays a role in relatively broad regional or systemic regulation. Further work will verify this dual-niche model to understand mechanisms underlying stem cell regulation.     

Intrahepatic cholangiojejunostomy (Longmire procedure) for recurrent bilioenteric anastomotic stricture with hepatolithiasis

Interventional procedure via percutaneous transhepatic route is often performed, as an initial treatment, in patients with benign bilioenteric anastomotic stricture. However, surgical management is required in most cases in which radiological intervention is unsuccessful. In this report, we describe a case of a 67-year-old woman with recurrent bilioenteric anastomotic stricture, accompanying bilateral hepatolitiasis after several times of transhepatic interventions. The patient underwent intrahepatic cholangiojejunostomy (Longmire procedure) and cholangioscopic lithotomy after resection of an atrophic left lateral segment resulting from hepatolithiasis. Although the damaged hilar bile duct had to be isolated and divided from the corresponding vasculature for re-anastomosis, it was quite impossible due to severe inflammatory change at the hepatic hilus. We, therefore, anastomosed the intact biliary stump on the cut surface of the left lateral segment to the jejunal loop with a stent tube. The patient's postoperative course was uneventful and she exhibited no evidence of cholangitis during follow-up period of 1 year after surgery. At present, the indications for intrahepatic cholangiojejunostomy for biliary obstruction, are quite limited, but biliary surgeons should keep this procedure in mind at the time of biliary reconstruction for benign proximal bile duct stricture, particularly in cases of multiply operated hilum.     

A case of malignant peritoneal mesothelioma successfully treated with systemic chemothrapy

A 64-year-old man with a 2-month history of abdominal distension was admitted for transient cerebral ischemic attack. A CT scan revealed massive ascites. Laparoscopy showed multiple whitish nodules on the visceral peritoneum and the omentum. Peritoneal biopsy revealed tumor cells consistent with malignant peritoneal mesothelioma (MPeM). Pemetrexed in combination with cisplatin was administered because it has been reported to be active in patients with MPeM. However his disease progressed. As second-line therapy paclitaxel was tried which yielded a complete response (CR). Eighteen months later he developed abdominal pain of the right upper region where a CT scan showed a mass with surrounding inflammation. As third-line therapy, gemcitabine was administered and again resulted in a CR. He is alive at 3 years from first presenting. Searches for case studies published in medical journals on MPeM were carried out, and 59 cases were analyzed in comparison with this case.