Relation between vacA subtypes, cytotoxin activity, and disease in Helicobacter pylori-infected patients from the netherlands

OBJECTIVE: The vacuolating cytotoxin of Helicobacter pylori (H. pylori) is encoded by vacA, of which allelic variation has been described. In the U.S., H. pylori strains with the signal sequence allele s1a are associated with enhanced gastric inflammation and with peptic ulcer disease (PUD). The m1 middle region allele is linked with more severe gastric epithelial damage. However, the distribution of H. pylori genotypes and the association with disease may be different in other geographical areas. The aim of this study was to establish whether vacA types among H. pylori isolates from Dutch patients are associated with disease. METHODS: The cytotoxin activity of the H. pylori isolates from 34 PUD patients and 46 patients with functional dyspepsia (FD) was assessed by an in vitro assay using HeLa cells as indicator cells. The vacA types and cagA status of the isolates were assessed by polymerase chain reaction (PCR). RESULTS: vacA s1-type H. pylori displayed cytotoxin activity more frequently than s2 vacA-type H. pylori (p = 0.003). This difference was not significant when only cagA+ H. pylori were considered. H. pylori isolates with the m1 vacA type exhibited a higher cytotoxin activity, independent of cagA (p = 0.006). Ninety-four percent (32/34) of the PUD patients and 74% (34/46) of the FD patients were infected with s1 vacA-type H. pylori (p = 0.04). When only cagA+ H. pylori were considered, s1 vacA type was not associated with disease. In addition, neither the s1a nor s1b subtypes correlated with disease. CONCLUSIONS: An association between vacA subtypes and disease could not be established in this patient population, due to the strong linkage between vacA s1 type and cagA.     

Identification and characterization of the capsular polysaccharide (K-antigen) locus of Porphyromonas gingivalis

Capsular polysaccharides of gram-negative bacteria play an important role in maintaining the structural integrity of the cell in hostile environments and, because of their diversity within a given species, can act as useful taxonomic aids. In order to characterize the genetic locus for capsule biosynthesis in the oral gram-negative bacterium Porphyromonas gingivalis, we analyzed the genome of P. gingivalis W83 which revealed two candidate loci at PG0106-PG0120 and PG1135-PG1142 with sufficient coding capacity and appropriate gene functions based on comparisons with capsule-coding loci in other bacteria. Insertion and deletion mutants were prepared at PG0106-PG0120 in P. gingivalis W50-a K1 serotype. Deletion of PG0109-PG0118 and PG0116-PG0120 both yielded mutants which no longer reacted with antisera to K1 serotypes. Restriction fragment length polymorphism analysis of the locus in strains representing all six K-antigen serotypes and K(-) strains demonstrated significant variation between serotypes and limited conservation within serotypes. In contrast, PG1135-PG1142 was highly conserved in this collection of strains. Sequence analysis of the capsule locus in strain 381 (K(-) strain) demonstrated synteny with the W83 locus but also significant differences including replacement of PG0109-PG0110 with three unique open reading frames, deletion of PG0112-PG0114, and an internal termination codon within PG0106, each of which could contribute to the absence of capsule expression in this strain. Analysis of the Arg-gingipains in the capsule mutants of strain W50 revealed no significant changes to the glycan modifications of these enzymes, which indicates that the glycosylation apparatus in P. gingivalis is independent of the capsule biosynthetic machinery.     

Distinct expression patterns of polycomb oncoproteins and their binding partners during the germinal center reaction

Polycomb group (PcG) genes encode two chromatin-binding protein complexes, the PRC1 and the PRC2 PcG complexes, which are essential for the maintenance of cell identity and play a role in oncogenesis. PcG complexes were recently identified as novel regulators of hematopoiesis, and appear to be expressed in a non-overlapping pattern in resting and mature follicular B cells. Using highly specific antisera in combination with immunohistochemistry and triple immunofluorescence, we investigated the expression pattern of nine human PcG genes in germinal center (GC) B cells and highly purified germinal center B cell subpopulations. PcG proteins were detected in characteristic binding patterns that were not necessarily related to mutually exclusive expression of the two PcG complexes. We conclude that the two PcG complexes are expressed throughout GC development, and that the fine composition of each complex is determined by the differentiation status of the cell. In addition, a subset of dividing cells with a centrocyte CD marker profile was identified that co-expresses core components of the PRC1 and PRC2 complex. We propose that these cells reflect a transitional stage between resting and dividing follicular B lymphocytes, and that they possibly represent the healthy precursors of nodal large B cell lymphomas.     

Lymphvascular space involvement compromises the survival of patients with stage I endometrial cancer: results of a multicenter study.

AIMS: To quantify the relative risk associated with lymphvascular space involvement (LVSI) on outcome measures in patients with apparent stage I endometrial cancer. METHODS: Six hundred and ninety nine consecutive patients with endometrial carcinoma apparent stage I, who underwent surgery in one of four gynecological oncology centers in Israel, comprised the study population. Forty cases with and 659 without LVSI were followed for a median time of 39 months. Recurrence free, disease specific and overall survival was compared between the two groups. The effect of LVSI, adjusted for other clinical and histo-pathological prognostic factors, was assessed by multivariate analysis. RESULTS: The univariate Kaplan-Meier procedure for survival analysis showed that patients with LVSI had lower recurrence free survival (p=0.0003), worse disease specific (p=0.0007) and overall survival (p<0.0001). Cox proportional hazards model demonstrated a trend toward shorter recurrence free survival (HR=2.0, 95% CI 0.9, 4.5; p=0.08), a worse disease specific survival (HR=2.8, 95% CI 1.1, 7.4; p=0.04) and decreased overall survival (HR=2.0, 95% CI 1.1, 3.8; p=0.03) in cases with LVSI. CONCLUSIONS: In patients with apparent stage I endometrial cancer the presence of LVSI, an independent poor prognostic factor, is associated with a two fold increased risk of death. The presence of LVSI warrants consideration when deciding upon post operative management.     

A randomized prospective study on the effect of short and long Buserelin treatment in women with repeated unsuccessful in vitro fertilization (IVF) cycles due to inadequate ovarian response

Fifty four women with repeated unsuccessful in vitro fertilization (IVF) cycles due to inadequate ovarian response to stimulation with human menopausal gonadotropins (hMG) participated in this study. They were randomized to receive either gonadotropin releasing hormone agonist (GNRHa), Buserelin, prior to and during induction of ovulation by hMG (Group I—long protocol), or GnRHa starting on the first day of the cycle together with induction of ovulation by hMG (Group II—short protocol). Mean follicular phase serum luteinizing hormone (LH) and progesterone (P) levels were significantly lower in Group I than in Group II (P<0.01). Cancellation rate was significantly lower in Group I than in Group II (P<0.01). The long GNRHa protocol resulted in statistically significant lower cancellation rates, more oocytes per pickup (OPU), more embryos trans-ferred per patient, and a higher pregnancy rate. Significantly more hMG ampoules and more treatments days were required in the long GNRHa protocol. Our data demonstrate that the use of GNRHa prior to and during ovarian stimulation with hMG offers a very good alternative for patients with repetitive unsuccessful IVF cycles due to inadequate response.     

Pregnancy Outcome in Gestational Diabetes with Preconceptional Diabetes Counselling

One hundred and thirty-six women with known previous gestational diabetes and normal glucose tolerance between pregnancies attended a preconceptional clinic at least 2 months before conception, and were regularly consulted by a diabetological team. Evaluation consisted of oral glucose tolerance test (OGTT), mean blood glucose, glycosylated haemoglobin and management by self-blood-glucose monitoring (SBGM) and nutritional counselling. When these patients were compared to a group of 154 patients with gestational diabetes who attended our clinic at different stages of pregnancy, the former had improved glucose homeostasis whereas the latter had more frequent elevations of fasting and postprandial glucose levels throughout pregnancy. This group had also more maternal complications and higher Caesarean section rates. Congenital anomalies were 0.65% among offspring of nonattenders, while none occurred in those with preconceptional counselling. Macrosomia and hypoglycaemia were significant neonatal complications in infants of nonattending mothers. We concur with the recommendation that preconceptional counselling in gestational diabetics is required to improve glucose homeostasis throughout pregnancy, and that appropriate evaluation of glucose intolerance should be included as part of prospective family planning.