A contemporary review of Clostridioides difficile infections in patients with haematologic diseases.

Clostridioides (Clostridium) difficile (C. difficile) infection is one of the most common causes of increased morbidity and mortality. Approximately 500 000 C. difficile infections (CDIs) occur each year in the United States, and they result in more than 29 000 deaths. Patients with haematologic diseases are at a higher risk for this infection due to frequent hospitalization and exposure to treatment-associated risk factors. Whilst several currently available antimicrobial agents offer resolution, recurrence of infection remains a major concern. Recent advancement in deciphering C. difficile virulence mechanisms and identification of its allies in contributing to the infection has led to the development of alternative treatment strategies. Here, we will provide a contemporary discussion of how major risk factors in haematologic diseases, such as immunosuppression, chemoradiation, use of antibiotic, proton pump inhibitor and opioid, and deficiency in butyrate and antimicrobial peptides contribute to C. difficile infection. Next, we will highlight different approaches to control and mitigate this infection such as antibiotic stewardship and faecal microbiota transplantation. Finally, we will explore several emerging treatments such as use of pre- and probiotics, immunotherapy and microbiome-sparing agents.

Seroprevalence of hepatitis E and Helicobacter pylori in a low socioeconomic area of a metropolitan city in a developing country.

This study aims to determine the prevalence of coinfection of H. pylori and hepatitis E virus (HEV) in the paediatric age group in an urban slum area of Karachi and identify risk factors associated with co-infection. Five hundred and forty children aged one to 15 years were investigated. Blood samples were collected and questionnaires completed on socio-demographic characteristics. Anti-H. pylori, HEV IgG and IgM antibodies were analysed by enzyme immunoassays (EIAs). The seroprevalence of H. pylori antibody was 47.2%, while that of HEV IgG and IgM was 14.4% and 2.4%, respectively. 12.4% exhibited seroprevalence for both H. pylori and HEV (IgG). In 67 (26%) cases positive for H. pylori IgG, HEV IgG positivity was also seen (P < 0.001). Only 13 (5%) positive for H. pylori were also positive for HEV IgM (P < 0.001). Only 11 (4%) HEV IgG-positive cases were H. pylori antibody-negative (P < 0.001). Hepatitis E virus was common in children who had access to municipal piped water (P = 0.025). H. pylori was common in children who used a non-flush toilet system (P < 0.001). Children exposed to H. pylori infection were also exposed to the risk of HEV.

A population-based study of irritable bowel syndrome in a non-Western population.

Previous studies have found no female predominance in irritable bowel syndrome (IBS) in non-Western countries. The aim of the study was to assess the prevalence and correlates of Rome II (IBS) in both sexes in Pakistan. A Population-based survey in a low-income inner city area using questionnaires to diagnose Rome II IBS and assess distress, disability and stressful life events. Data were collected from 880/938 (93%) randomly selected residents. 13.4% of women and 13.1% men met criteria for Rome II IBS; 34 (3.9%) had diarrhoea-predominant, 59 (6.7%) had constipation-predominant IBS and 24 (2.7%) had 'mixed IBS'. In logistic regression analysis, IBS was associated in men with high income (OR = 1.56; 95% CI: 1.05-2.3) and few years of education (OR = 2.17; 95% CI: 1.2-3.9) and in women with being married (OR = 3.6; 95% CI: 1.1-11.9) and stressful life events score (OR = 1.14; 95% CI: 1.01-1.3). Disability was associated with constipation-predominant IBS (OR = 1.99; 95% CI: 1.1-3.6), distress (OR = 1.19; 95% CI: 1.14-1.23) and stressful life events (OR = 1.19; 95% CI: 1.1-1.3). Investigations were more likely in men (54%) than in women (27%) (P = 0.003). These findings suggest that the equal sex ratio of IBS in urban Pakistan could result from a close association between marked distress and IBS in men similar to that found in women in western studies.

A method to detect particle-specific antibodies against Ku and the DNA-dependent protein kinase catalytic subunit in autoimmune sera.

Sera from patients with systemic lupus erythematosus, polymyositis, scleroderma, and mixed connective tissue disease are frequently characterized by the presence of high levels of autoantibodies directed against linked sets of nuclear proteins. One of these autoantigen systems is made up of Ku and the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), proteins that are essential for double-strand DNA break repair and for the related process of V(D)J recombination. Ku and DNA-PKcs bind avidly to DNA ends in vivo and in vitro and form an active protein kinase complex. One hypothesis is that this assembled nucleoprotein particle, rather than its component proteins, is a primary trigger for the autoimmune response and thus a major target for the resulting autoantibodies. To screen for particle-specific antibodies, we developed an assay in which the fully native nucleoprotein particle is reconstituted in vitro and is tethered to the surface of an ELISA plate via a streptavidin-biotin linkage. These particles are recognized efficiently by monoclonal antibodies and by autoantibodies present in patient sera. The assay may detect a broader spectrum of epitopes than a conventional ELISA in which Ku and DNA-PKcs are adsorbed directly to a plastic surface. The method will be advantageous for high-throughput screening for antibodies and other ligands that bind the assembled DNA-dependent protein kinase complex.

The role of surveillance endoscopic retrograde cholangiopancreatography in preventing episodic cholangitis in patients with recurrent common bile duct stones.

BACKGROUND AND STUDY AIMS: Approximately 2-7% of patients who have undergone previous removal of bile duct stones have recurrence often presenting as ascending cholangitis. The aim of this study was to identify the incidence, clinical presentation, and objective findings in this group of patients. Additionally, the effect of surveillance endoscopic retrograde cholangiopancreatography (ERCP) in preventing cholangitis, was studied. PATIENTS AND METHODS: Two thousand and ninety-six patients who underwent ERCP for cholelithiasis were studied with 45 of these patients being identified as having recurrent common bile duct stones. Of the 45, 13 had two or more recurrences without having any obvious predisposing factors. The mean age of the 13 patients was 57 years. The characteristics of 13 patients were reviewed, including sphincterotomy size, liver function tests, and contrast drainage time. RESULTS: All 13 patients with recurrent stones presented with ascending cholangitis. Stones were found to be soft, brown and accompanied by a large amount of sludge. The common bile duct in all 13 patients was noted to be dilated and had notable, widely patent sphincterotomes. There was significant delayed drainage in 77% of these patients. Yearly surveillance ERCPs were performed in the 13 patients, the incidence of acute cholangitis episodes per patient decreased from 2 to 0.6 with a four-year follow-up. CONCLUSION: In a subgroup of patients with multiple common bile duct stone recurrences, annual surveillance ERCP with stone removal decreases the incidence of recurrent episodes of ascending cholangitis as well as its associated morbidity and mortality.

Activity profile of placental superoxide-superoxide dismutase system in pregnant mice and its possible relation with placental steroidogenesis.

Placenta in mouse generate increasing quantities of superoxide dismutase from day 13 of pregnancy until parturition. This is associated with a concomitant reduction in the activity of superoxide radical. This findings points to the steroidogenic control of the later half of pregnancy by the placental axis. Parturition is associated with an abrupt spurt in superoxide radical. This is a novel finding and could be a consequence of the estrogen surge at labour. It is suggested that this abrupt increase in superoxide radical level at parturition may remould the placental membrane fluid at the point of its attachment with uterine membranes so as to facilitate the separation of placenta from uterus.

Immobilization of invertase on sepharose-linked enzyme glycosyl recognizing polyclonal antibodies.

Polyclonal antibodies directed against the yeast invertase glycosyls were raised by immunizing rabbits with neoglycoprotein-I and neoglycoprotein-II. The neoglycoproteins were prepared by separately coupling the N-linked large and small molecular weight yeast invertase oligosaccharides respectively to bovine serum albumin with the help of glutaraldehyde. Antibodies specifically recognizing the invertase oligosaccharides were purified from the sera of rabbits immunized with either neoglycoprotein using an affinity column of sepharose 4B-linked yeast invertase. Specific immunoaffinity supports for the immobilization of invertase were constructed by coupling the affinity-purified antineoglycoprotein-I or antineoglycoprotein-II antibodies to cyanogen bromide activated sepharose-4B. Both the affinity adsorbants were effective in binding and improving the thermal stability of invertase. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 605-609, 1997.

Immobilization and stabilization of horseradish peroxidase isoforms.

Purified anionic and cationic isoforms of horseradish peroxidase (HRP) immobilized by coupling the amino acid side-chain amino groups and/or carbohydrate moieties to Sepharose have been studied for their resistance to denaturation. The isoforms were treated with periodate followed by ethylenediamine to generate additional amino groups in the glycosyl residues. The immobilized preparations were: Preparation I (Sp-aHRP, Sp-cHRP), in which HRP was covalently immobilized via side-chain amino groups exclusively; Preparation II (Sp-NHaHRP, Sp-NHcHRP), in which periodate and ethylenediamine-treated HRP was covalently immobilized via side-chain amino groups and amino groups incorporated into glycosyl residues. HRP isoforms in preparation II lacked about 33-55% carbohydrate. Both strategies of immobilization induced significant stabilization against denaturation. Inclusion of 2 mM calcium enhanced isoenzyme stability significantly.

Covalent immobilization of invertase and horseradish peroxidase on concanavalin A-Seralose via carbohydrate moieties.

Invertase from Baker's yeast (Saccharomyces cerevisiae) and Horseradish peroxidase (HRP) were covalently immobilized on Concanavalin A precoupled to Seralose via carbohydrate moieties. Covalent coupling of glycoenzymes was achieved by periodate induced aldehydic groups of glycosyls with amino groups of Concanavalin A, at different pH values. A bifunctional reagent such as glutaraldehyde crosslinks the glycoenzymes with lectin both intra and intermolecularly. Therefore, attempts were made to introduce covalent linkages between glycoenzymes and Concanavalin A-Seralose without intramolecular crosslinking in either. The immobilized preparations of glycoenzymes exhibited high yield of immobilization and eta value. About 90 and 85% covalent coupling could be observed in invertase and HRP at pH 7.0 respectively, as determined by treatment with 0.5 M methyl alpha-D-mannopyranoside. All immobilized glycoenzyme preparations exhibited marked stabilization towards thermal inactivation.

Immobilization and stabilization of invertase using specific polyclonal antibodies.

Antisera raised in rabbits to baker's-yeast invertase significantly activated the enzyme in vitro. The antisera contained precipitating antibodies, a significant fraction of which appeared to be directed against the glycosyl residues of the enzyme. Invertase could be immobilized as insoluble enzyme antibody adducts or by binding to a Sepharose matrix precoupled with the gamma-globulin fraction derived from the antisera. The immobilized invertase preparations exhibited high enzyme activity and had markedly enhanced thermal stability, which could be further improved by cross-linking with glutaraldehyde.

Scintigraphic studies of rectal emptying in patients with constipation and defecatory difficulty.

We prospectively evaluated 38 adult patients with chronic constipation with and without defecatory difficulties using a newly described scintigraphic test to measure rectal emptying and compared them to 20 healthy controls. All patients underwent anorectal manometry, and 30 who complained of infrequent defecation underwent a colonic transit study using radiopaque markers. Control subjects promptly evacuated both 100 ml and 200 ml artificial stool in a characteristic fashion, but three evacuated none of the 100-ml volume and two had no evacuation of the 200-ml stool (inhibited controls). Constipated patients exhibited three patterns of emptying: (1) normal emptying of both volumes (47%); (2) poor emptying of both volumes or inhibited defecation (29%); and (3) normal emptying of the 200-ml but abnormal evacuation of the 100-ml volume (24%). An abnormal expulsion pattern during manometry occurred in 21% of patients and was strongly associated with the inhibited defecation pattern. However, defecation patterns could not be predicted on the basis of age, gender, symptoms, duration of complaints, colonic transit, or other rectal manometric parameters. Although rectal scintigraphy has potential advantages as a diagnostic test in terms of quantitation and decreased radiation exposure, the inability of the test to distinguish patients with slow transit constipation and defecatory complaints makes the potential utility of this test of uncertain value in clinical and investigative settings.

Jejunal vasculitis with protein-losing enteropathy after bone marrow transplantation.

A 37-yr-old white man experienced crampy abdominal pain beginning 21 days after successful bone marrow transplantation for chronic myelogenous leukemia. Generalized edema and hypoproteinemia developed. Symptoms persisted until 61 days post-transplant, when the patient developed an acute abdomen. At laparotomy, an edematous segment of jejunum was resected. Pathological examination showed submucosal vasculitis and necrotizing enteritis. Serum protein and albumin levels returned to normal within a few weeks after surgery. Vasculitis of the gastrointestinal tract should be considered in the differential diagnosis of protein-losing enteropathy after bone marrow transplantation.

Torsade de pointes in a patient receiving intravenous vasopressin.

A patient experienced hypertension, bradycardia, QT prolongation, and multiple episodes of torsade de pointes while receiving an iv vasopressin infusion. The dysrhythmias were attributed to vasopressin, but may have been potentiated by hypomagnesemia. Upon vasopressin discontinuation, ECG findings returned to normal before magnesium supplementation. Vasopressin may contribute to the development of torsade de pointes.