Motility and flagellin gene expression in the fish pathogen Vibrio salmonicida: effects of salinity and temperature

The success of several Vibrio species, including Vibrio cholerae, Vibrio anguillarum and Vibrio fischeri in colonizing their symbiont, or causing infection is linked to flagella-based motility. It is during early colonization or the initial phase of infection that motility appears to be critical. In this study we used Vibrio salmonicida, a psychrophilic and moderate halophilic bacterium that causes cold-water vibriosis in seawater-farmed Atlantic salmon (Salmo salar), to study motility and expression of flagellins under salt conditions mimicking the initial and later phases of an infection. Our results, which are based on motility in semi-solid agar, membrane protein proteomics, quantitation of flagellin gene expression, challenge infection of fish, and microscopy, show that V. salmonicida is highly motile, expresses elevated levels of flagellins, and typically contains several polar flagella under salt conditions that are seawater-like. In contrast, V. salmonicida cells are non-motile and express significantly lower levels of flagellins under physiological-like salt conditions.     

Systemic inflammation in acute intermittent porphyria: a case–control study

This study aimed to examine whether acute intermittent porphyria (AIP) is associated with systemic inflammation and whether the inflammation correlates with disease activity. A case–control study with 50 AIP cases and age‐, sex‐ and place of residence‐matched controls was performed. Plasma cytokines, insulin and C‐peptide were analysed after an overnight fast using multiplex assay. Long pentraxin‐3 (PTX3) and complement activation products (C3bc and TCC) were analysed using enzyme‐linked immunosorbent assay (ELISA). Urine porphobilinogen ratio (U‐PBG, µmol/mmol creatinine), haematological and biochemical tests were performed using routine methods. Questionnaires were used to register AIP symptoms, medication and other diseases. All 27 cytokines, chemokines and growth factors investigated were increased significantly in symptomatic AIP cases compared with controls (P < 0·0004). Hierarchical cluster analyses revealed a cluster with high visfatin levels and several highly expressed cytokines including interleukin (IL)‐17, suggesting a T helper type 17 (Th17) inflammatory response in a group of AIP cases. C3bc (P = 0·002) and serum immunoglobulin (Ig)G levels (P = 0·03) were increased significantly in cases with AIP. The U‐PBG ratio correlated positively with PTX3 (r = 0·38, P = 0·006), and with terminal complement complex (TCC) levels (r = 0·33, P = 0·02). PTX3 was a significant predictor of the biochemical disease activity marker U‐PBG in AIP cases after adjustment for potential confounders in multiple linear regression analyses (P = 0·032). Prealbumin, C‐peptide, insulin and kidney function were all decreased in the symptomatic AIP cases, but not in the asymptomatic cases. These results indicate that AIP is associated with systemic inflammation. Decreased C‐peptide levels in symptomatic AIP cases indicate that reduced insulin release is associated with enhanced disease activity and reduced kidney function.     

Transmission of infectious salmon anaemia virus (ISAV) in farmed populations of Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis>)

Summary. In the present study, 24 smolt production sites were screened for the presence of infectious salmon anaemia virus (ISAV) with the help of a specific real-time RT PCR assay, and 22 of these sites had smolts that were positive. If these smolt production sites are representative for the prevalence of ISAV in Norwegian smolts, then most marine production sites must be considered to be positive for ISAV. In addition, 92 European ISAV isolates have been genotyped based on the hemagglutinin-esterase gene (HE), and their distribution pattern was analysed. This pattern has been coupled to information about the origin of smolt, eggs, and broodfish in those cases where it has been possible to obtain such information, and with information about ISAV in neighbouring farms. The pattern suggests that an important transmission route for the ISAV could be that the salmon farming industry in Norway is circulating some of the isolates in the production cycle, i.e. some sort of vertical or transgenerational transmission may occur. It has also been shown that avirluent ISAV isolates are fairly common in Norwegian farmed salmon. Based on this, it is hypothesized that the change from avirulent to virulent ISAV isolates is a stochastic event that is dependent on the replication frequency of the virus and the time available for changes in a highly polymorphic region (HPR) of the HE gene to occur. This, and the possibility that only avirluent ISAV isolates are vertically transmitted, may explain why ISA most often occurs at marine sites and why no more than about 15 farms get ISA every year in Norway.     

Patients’ Reported Reasons for Non-Use of an Internet-Based Patient-Provider Communication Service: Qualitative Interview Study

Background

The adoption of Internet-based patient–provider communication services (IPPC) in health care has been slow. Patients want electronic communication, and the quality of health care can be improved by offering such IPPCs. However, the rate of enrollment in such services remains low, and the reasons for this are unclear. Knowledge about the barriers to use is valuable during implementation of IPPCs in the health care services, and it can help timing, targeting, and tailoring IPPCs to different groups of patients.

Objective

The goal of our study was to investigate patients’ views of an IPPC that they could use from home to pose questions to nurses and physicians at their treatment facility, and their reported reasons for non-use of the service.

Methods

This qualitative study was based on individual interviews with 22 patients who signed up for, but did not use, the IPPC.

Results

Patients appreciated the availability and the possibility of using the IPPC as needed, even if they did not use it. Their reported reasons for not using the IPPC fell into three main categories: (1) they felt that they did not need the IPPC and had sufficient access to information elsewhere, (2) they preferred other types of communication such as telephone or face-to-face contact, or (3) they were hindered by IPPC attributes such as login problems.

Conclusions

Patients were satisfied with having the opportunity to send messages to health care providers through an IPPC, even if they did not use the service. IPPCs should be offered to the patients at an appropriate time in the illness trajectory, both when they need the service and when they are receptive to information about the service. A live demonstration of the IPPC at the point of enrollment might have increased its use.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00971139","term_id":"NCT00971139"}}NCT00971139; http://clinicaltrial.gov/ct2/show/{"type":"clinical-trial","attrs":{"text":"NCT00971139","term_id":"NCT00971139"}}NCT00971139 (Archived by WebCite at http://www.webcitation.org/6KlOiYJrW).     

Lung function at 10 yr is not impaired by early childhood lower respiratory tract infections

The causal relationship between lower respiratory tract infections (LRIs) in early life and reduced lung function later in childhood is unsettled. Therefore, we assessed whether LRIs the first 2 yr of life influenced lung function development from birth to school age. In the prospective Oslo birth cohort, ‘the Environment and Childhood Asthma (ECA) study’ lung function was measured at birth in 802 infants by tidal flow volume loops and in 664 infants by passive respiratory mechanics and half yearly questionnaires, including LRI questions, were completed until 2 yr of age. The present study includes 607 children with information about LRIs the first 2 yr of life and successfully forced expiratory flow (FEF) volume measurements at the 10‐yr follow‐up assessment. At 10 yr of age, FEF at 50% of forced vital capacity (FEF₅₀) (mean 95% confidence interval) was reduced in children with at least one bronchiolitis (85.0, 80.6–89.5, p = 0.020) or bronchitis (86.2, 82.6–89.8, p = 0.030) or ≥3 LRIs (83.4, 78.1–88.8, p = 0.017) when compared with no LRIs (90.6, 88.8–92.5) by 2 yr of life. The effects were significant in girls only when stratifying for gender. Among girls with later bronchiolitis compliance of the respiratory system (3.64, 3.17–4.10 vs. 4.18, 3.98–4.37, p = 0.031) and the ratio of time to peak tidal expiratory flow to total expiratory time (t_PTEF/t_E) measured at birth was significantly reduced (0. 26, 0.23–0.29 vs. 0.32, 0.30–0.33, p = 0.005) when compared with children with no LRIs. Change in lung function from birth (by t_PTEF/t_E) to 10 yr of age was not significantly associated with LRIs the first 2 yr of life, and LRIs by 2 yr of life were not significantly associated with lung function at 10 yr of age in regression analyses including lung function at birth and other possible predictors of lung function at 10 yr. In our study, LRIs during the first 2 yr of life did not impair lung function development from birth until 10 yr of age.     

The effect of stimulus duration using the Brookler-Grams closed-loop caloric irrigator.

Nystagmic responses to traditional 40-sec, 30 degrees C water calorics were recorded and compared to those obtained with the Brookler-Grams closed-loop irrigator using 30 degrees C, 40-, 50-, and 60-sec irrigations. Significant differences were noted between the responses to the water irrigator and the 40- and 50-sec closed-loop irrigations. The 60-sec closed-loop irrigation produced responses that were equivalent to the responses obtained with the water irrigation in slow component velocity, amplitude, frequency, latency, and duration. The 30 degrees C 60-sec closed-loop irrigation is an acceptable stimulus in electronystagmographic caloric testing.     

Sub-cellular pathology of scrapie: coated pits are increased in PrP codon 136 alanine homozygous scrapie-affected sheep

Sub-cellular studies of transmissible spongiform encephalopathies (TSEs) have been carried out on several animal species and human beings. However, studies of optimal perfusion-fixed tissues have largely been confined to examination of rodents. Using a recently developed technique, heads of scrapie-affected sheep and controls were perfusion fixed with mixed aldehydes. The obexes were immunohistochemically labelled with PrP antibodies, and the dorsal motor nucleus of the vagal nerve was examined by electron microscopy. Irregular neuritic profiles with highly invaginated membranes, associated with coated pits were found in all scrapie-affected sheep, but not in controls. Interestingly, they were consistently more frequent in the homozygous A(136) sheep. This is the first report describing sub-cellular differences in pathology associated with different PrP genotypes. Rarely, amorphous material, or sparse fibrillar structures, were present in the extracellular space. The changes were often associated with irregular plasmalemma and frequent coated pits. Vacuolation typical of TSEs, dystrophic neurites and variable gliosis were present. Herniation of membranes and organelles from apparently healthy processes into adjacent vacuoles and dendrites was also observed. We suggest that the increase in coated pits and plasmalemma invagination is related to an attempted internalisation of aggregated disease-specific PrP, or protofilaments, from the extracellular space.