Finnish Campylobacter jejuni strains of multilocus sequence type ST-22 complex have two lineages with different characteristics

Background

Campylobacter jejuni is the major cause of human bacterial gastroenteritis worldwide, and in a minority of cases, post-infectious complications may occur. ST-22 complex (usually Penner serotype 19) strains have been overrepresented among patients with postinfectious complications of campylobacteriosis. We here present a characterization of a collection of 27 Finnish C. jejuni strains of ST-22 complex, from humans (22 strains) and animal sources (five strains), with the aim of contributing to our knowledge of the pathogenesis of C. jejuni infections.

Methodology/Principal Findings

All strains were analyzed by pulsed-field gel electrophoresis (PFGE) genotyping, lipo-oligosaccharide (LOS) locus class, Y-glutamyl transpeptidase (GGT) activity, in vitro biofilm formation ability, invasion and adhesion in HeLa cells and induction of IL-8 production. ST-22 complex contained five STs (ST-22; ST-1947; ST-1966; ST-3892; ST-3996) which were homogeneous in having sialylated LOS class A₁ but on the other hand were distinguished into two major lineages according to the major STs (ST-22 and ST-1947) by different PFGE genotypes and certain other characteristics. All ST-22 strains had similar SmaI PFGE profiles, were GGT positive, and formed biofilms, except one strain, while ST-1947 strains were all GGT negative, did not form biofilm, had significantly higher motility than ST-22 (p<0.05) and had their SmaI PFGE profile. Invasion and adhesion as well as induction of IL-8 production on HeLa cells were strain-dependent characteristics.

Conclusions/Significance

ST-22 complex strains, reveal potential for molecular mimicry in host interactions upon infection as they all express sialylated LOS class A₁. The two major STs, ST-22 and ST-1947 formed two homogeneous lineages, which differed from each other both phenotypically and genetically, suggesting that the strains may have evolved separately, perhaps by interacting with different spectra of hosts. Further studies are needed in order to understand if these two lineages are associated with different disease outcomes.     

Conformational changes of apoB-100 in SMase-modified LDL mediate formation of large aggregates at acidic pH

During atherogenesis, the extracellular pH of atherosclerotic lesions decreases. Here, we examined the effect of low, but physiologically plausible pH on aggregation of modified LDL, one of the key processes in atherogenesis. LDL was treated with SMase, and aggregation of the SMase-treated LDL was followed at pH 5.5-7.5. The lower the pH, the more extensive was the aggregation of identically prelipolyzed LDL particles. At pH 5.5-6.0, the aggregates were much larger (size >1 μm) than those formed at neutral pH (100-200 nm). SMase treatment was found to lead to a dramatic decrease in α-helix and concomitant increase in β-sheet structures of apoB-100. Particle aggregation was caused by interactions between newly exposed segments of apoB-100. LDL-derived lipid microemulsions lacking apoB-100 failed to form large aggregates. SMase-induced LDL aggregation could be blocked by lowering the incubation temperature to 15°C, which also inhibited the changes in the conformation of apoB-100, by proteolytic degradation of apoB-100 after SMase-treatment, and by HDL particles. Taken together, sphingomyelin hydrolysis induces exposure of protease-sensitive sites of apoB-100, whose interactions govern subsequent particle aggregation. The supersized LDL aggregates may contribute to the retention of LDL lipids in acidic areas of atherosclerosis-susceptible sites in the arterial intima.     

Psychosocial group intervention to enhance self-management skills of people with dementia and their caregivers: study protocol for a randomized controlled trial

ABSTRACT: BACKGROUND: After diagnosis of a dementing illness patients and their spouses have many concerns related to the disease and their future. This often leads to poor psychological well-being and reduced health related quality of life (HRQoL) of the family. Support for self-management skills has been proven to be an effective method to improve prognosis of asthma, heart failure and osteoarthritis. However, self-management interventions have not been studied in dementia. Therefore, our aim was to examine in an objective-oriented group intervention the efficacy of self-management support program (SMP) on the HRQoL of dementia patients and their spousal caregivers as well as on the sense of competence and psychological well-being of care-givers. METHODS: During the years 2011-12, 160 dementia patients and their spouses will be recruited from memory clinics and randomized into two arms: 80 patients for group-based SMP sessions including topics selected by the participants, 80 patients will serve as controls in for usual community care. Sessions may include topics on dementia, community services, active lifestyle and prevention for cognitive decline, spousal relationship, future planning and emotional well-being. The patients and spouses will have their separate group sessions (10 participants/group) once a week for 8 weeks. Main outcome measures will be patients' HRQoL (15D) and spousal caregivers' HRQoL (RAND-36), and sense of competence (SCQ). Secondary measures will be caregivers' psychological well-being (GHQ-12) and coping resources, patients' depression, cognition and signs of frailty. Data concerning admissions to institutional care and the use and costs of health and social services will be collected during a two year follow-up. DISCUSSION: This is a "proof -of-concept" study to explore the efficacy of group support for self-management skills among dementia families. It will also provide data on cost-effectiveness of the intervention.     

Bovine Campylobacter jejuni Strains Differ from Human and Chicken Strains in an Analysis of Certain Molecular Genetic Markers

The association of four new genetic markers with a chicken, bovine, or human host was studied among 645 Campylobacter jejuni isolates. The γ-glutamate transpeptidase gene and dmsA were common in human and chicken isolates but uncommon among bovine isolates. In the t test, bovine isolates differed significantly (P < 0.05) from human and chicken isolates.     

Genome-wide Association Study in a High-Risk Isolate for Multiple Sclerosis Reveals Associated Variants in STAT3 Gene

Genetic risk for multiple sclerosis (MS) is thought to involve both common and rare risk alleles. Recent GWAS and subsequent meta-analysis have established the critical role of the HLA locus and identified new common variants associated to MS. These variants have small odds ratios (ORs) and explain only a fraction of the genetic risk. To expose potentially rare, high-impact alleles, we conducted a GWAS of 68 distantly related cases and 136 controls from a high-risk internal isolate of Finland with increased prevalence and familial occurrence of MS. The top 27 loci with p < 10⁻⁴ were tested in 711 cases and 1029 controls from Finland, and the top two findings were validated in 3859 cases and 9110 controls from more heterogeneous populations. SNP (rs744166) within the STAT3 gene was associated to MS (p = 2.75 × 10⁻¹⁰, OR 0.87, confidence interval 0.83–0.91). The protective haplotype for MS in STAT3 is a risk allele for Crohn disease, implying that STAT3 represents a shared risk locus for at least two autoimmune diseases. This study also demonstrates the potential of special isolated populations in search for variants contributing to complex traits.     

The distribution of 14C-arachidonic acid in hamster lungs is sensitive to quinacrine

Isolated hamster lungs were labelled with ¹⁴C-arachidonic acid. When the lungs were ventillated with a respirator only a small amount of radioactivity was released to the perfusion effluent. This release was not changed significantly by pulmonary infusion of quicacrine (0.5 mM), a known inhibitor of phospholipase A₂. After the perfusion about 75% of the radioactivity in the lungs was in phospholipids, mainly in phosphatidylcholine, phosphatidylethanolamine and phosphatidylinostil and to a lesser degree in phosphatidylserine and phosphatidic acid. About one fourth of the radioactivity was in neutral lipids (tri- and diacylglycerols) and as free unmetabolized ¹⁴C-arachiodonic acid. Pulmonary infusion of quinacrine increased the amount of radioactivity in diacylglycerols and phosphatidylinositol but had no effect on that in phosphatidylcholine, phosphatidylserine, phosphatidic acid and triacylglycerols. The amount of radioactivity in phosphatidylethanolamine was decreased by quinacrine and increased in the vicinity of an unidentified phospholipid-quinacrine complex. The present study indicates that the distribution of ¹⁴C-arachidonic acid in hamster lung lipids is sensitive to quinacrine. The detected changes can, however, not be explained by an overall inhibition of phospholipase A₂ activities.     

Ultrastructure and some plasma membrane characteristics of ozone-exposed loblolly pine needles

Tropospheric ozone is a widespread and phytotoxic air pollutant in the industrialized world and causes reduced growth in many tree species. It is therefore important that, for example, the responses of the economically important loblolly pine to ozone are determined thoroughly. The objective of the study was to determine changes in ultrastructure, the vanadate-sensitive ATPase activity of the plasma membrane, the fatty acids of plasma membrane phospholipids, visible injury, and growth in loblolly pine (Pinus taeda L.) needles exposed to different concentrations of ozone in open-top chambers. The treatments were charcoal filtered air (CF), nonfiltered air (NF), or NF-air with ozone added for 12 h daily at 1.5- or 2-fold ambient ozone concentrations from May to October, 1993. Visible injury was more severe in the high than in the low ozone treatments. Growth of needles of the first flush of 1993 was significantly reduced in the highest ozone treatment. Two types of ultrastructural injury, characterized as either acute or chronic, were observed in mesophyll cells under elevated ozone. The acute injury lead to cell collapse and death. The chronic injury, characterized by several symptoms, e.g. decreased chloroplast size and increased density of the stroma, was also found in the NF ozone treatment. Increased density of chloroplast stroma and swelling of thylakoids were transient symptoms, suggesting partial recovery as ozone concentrations decreased in fall. Ozone induced decreases in the specific activity of vanadate-sensitive ATPase of plasmalemma and in the degree of unsaturation in phospholipid fatty acids. The detected reduced needle growth, ultrastructural injury and perturbations in the function and composition of the plasma membrane indicate susceptibility of loblolly pine to ozone. Changes in the plasma membrane phospholipids may have contributed to the decrease in ATPase activity. Injury to the key enzyme of the plasma membrane can directly affect intracellular processes. In the long-term, decreased viability of needles can lead to reductions in loblolly pine productivity.     

Isolation and Identification of Helicobacter spp. from Canine and Feline Gastric Mucosa

It is known that virtually all healthy adult dogs and cats harbor spiral helicobacters in their gastric mucosa. Three species, Helicobacter felis, Helicobacter bizzozeronii, and Helicobacter salomonis have been isolated in vitro from the gastric mucosa of these animals. The aims of this study were to evaluate the efficacy of an isolation method for canine and feline gastric helicobacters that has been developed at the University of Helsinki; to estimate the prevalence and distribution of these taxa in the samples examined; and to assess the efficacy and validity of an extensive set of standardized conventional phenotypic tests, whole-cell protein profiling, and ultrastructural analysis in identifying the different species isolated from canine and feline gastric mucosa. We cultured 95 and 22 gastric mucosal biopsies from dogs and cats, respectively. Twenty-one H. bizzozeronii strains, 8 H. felis strains, 8 H. salomonis strains, 3 mixed cultures, 2 “Flexispira rappini”-like organisms, and 3 as yet uncharacterized strains were isolated from the dogs, and 3 H. felis strains were isolated from the cats. The methods used here yielded Helicobacter isolation rates of 51% from dogs and 13.6% from cats, which exceed those reported previously. The main difficulties were primary isolation, mixed cultures, and identification to the species level. In the species identification, a detailed morphological examination was found to yield important phenotypic characteristics. A large panel of biochemical and tolerance tests did not clearly differentiate the closely related species H. bizzozeronii, H. felis, and H. salomonis. Highly standardized whole-cell protein profiling was shown to be an excellent method for species identification. Improvements in culture conditions for these bacteria are still needed, especially for cats. A genetic identification method not requiring culture is needed for future studies of these very fastidious helicobacters, as the clinical significance and ecology of these species within the gastric mucosa of the domestic carnivores remain largely unknown.     

Effect of electrolyte and solvent composition on capillary electrophoretic separation of some pharmaceuticals in non-aqueous media

Non-aqueous capillary electrophoresis was used to study the separation selectivity of positively charged drug substances and negatively charged diuretics. Study was made of the effects of organic solvent composition and the background electrolyte on the separation. The separation selectivity could be altered considerably by varying the methanol/acetonitrile composition. In addition, the migration order and the resolution of the pharmaceuticals could be altered merely by changing the electrolyte cation or the anion. The electrolytes tested were alkali metal acetates, ammonium acetate, ammonium chloride and ammonium bromide. As with aqueous background electrolyte solutions, the electroosmotic flow was decreased with increasing size of the alkali metal cation of the electrolyte in methanol/acetonitrile 50:50 (v/v).