Specific binding of a hypersensitive lignification elicitor from Puccinia graminis f. sp. tritici to the plasma membrane from wheat (Triticum aestivum L.)

We have recently reported the isolation and characterization of a glycoprotein (M_r 67 000) from germ-tube walls of Puccinia graminis f. sp. tritici which elicits the cellular hypersensitive lignification response in wheat (G. Kogel et al., 1988, Physiol. Mol. Plant Pathol. 33, 173–185). The present study uses this glycoprotein, referred to as Pgt elicitor, to identify putative elicitor targets in wheat cell membranes. In enzyme-linked immunosorbent assays using anti-Pgt elicitor antibodies, specific binding sites for Pgt elicitor were detected in highly purified plasma-membrane vesicles of wheat (Triticum aestivum L.) primary leaf cells. Binding proved to be independent of the presence or absence in wheat of the Sr5 gene for rust resistance, and also occurred on barley (Hordeum vulgare L.) plasma membrane. The binding sites have an Mr of 30 000 and 33 000, respectively, and binding activity was not lost in the presence of sodium dodecyl sulfate. [¹⁴C]imido-Pgt elicitor was used to determine the apparent K _d value for specific binding, found to be 2.0 M, and the maximum content of binding sites, found to be 250 pmol per mg of plasma-membrane protein. The relevance of the elicitor binding for the outcome of the interaction of P. graminis and wheat is discussed.Abbreviations BSA bovine serum albumin - ELISA enzyme linked immunosorbent assay - IDPase inosine 5-diphosphatase - MPLC medium-pressure liquid chromatography - MF microsomal fraction - Pgt elicitor elicitor of Puccinia graminis f. sp. tritici - SDS sodium dodecyl sulfate - Pre U₃, Pre U₁ pure plasma membrane from wheat cultivar Prelude and plasma membrane contaminated by intracellular membrane, respectively This work was supported by the Deutsche Forschungsgemeinschaft. We wish to thank C. Larsson, Lund, Sweden for his kind support in the preparation of plasma membrane.     

Reduction of claustrophobia with short-bore versus open magnetic resonance imaging: a randomized controlled trial

Background

Claustrophobia is a common problem precluding MR imaging. The purpose of the present study was to assess whether a short-bore or an open magnetic resonance (MR) scanner is superior in alleviating claustrophobia.

Methods

Institutional review board approval and patient informed consent were obtained to compare short-bore versus open MR. From June 2008 to August 2009, 174 patients (139 women; mean age = 53.1 [SD 12.8]) with an overall mean score of 2.4 (SD 0.7, range 0 to 4) on the Claustrophobia Questionnaire (CLQ) and a clinical indication for imaging, were randomly assigned to receive evaluation by open or by short-bore MR. The primary outcomes were incomplete MR examinations due to a claustrophobic event. Follow-up was conducted 7 months after MR imaging. The primary analysis was performed according to the intention-to-treat strategy.

Results

With 33 claustrophobic events in the short-bore group (39% [95% confidence interval [CI] 28% to 50%) versus 23 in the open scanner group (26% [95% CI 18% to 37%]; P = 0.08) the difference was not significant. Patients with an event were in the examination room for 3.8 min (SD 4.4) in the short-bore and for 8.5 min (SD 7) in the open group (P = 0.004). This was due to an earlier occurrence of events in the short-bore group. The CLQ suffocation subscale was significantly associated with the occurrence of claustrophobic events (P = 0.003). New findings that explained symptoms were found in 69% of MR examinations and led to changes in medical treatment in 47% and surgery in 10% of patients. After 7 months, perceived claustrophobia increased in 32% of patients with events versus in only 11% of patients without events (P = 0.004).

Conclusions

Even recent MR cannot prevent claustrophobia suggesting that further developments to create a more patient-centered MR scanner environment are needed.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00715806","term_id":"NCT00715806"}}NCT00715806     

Exploratory subgroup analysis in clinical trials by model selection

The interest in individualized medicines and upcoming or renewed regulatory requests to assess treatment effects in subgroups of confirmatory trials requires statistical methods that account for selection uncertainty and selection bias after having performed the search for meaningful subgroups. The challenge is to judge the strength of the apparent findings after mining the same data to discover them. In this paper, we describe a resampling approach that allows to replicate the subgroup finding process many times. The replicates are used to adjust the effect estimates for selection bias and to provide variance estimators that account for selection uncertainty. A simulation study provides some evidence of the performance of the method and an example from oncology illustrates its use.     

Interferon-γ Is a Crucial Activator of Early Host Immune Defense against Mycobacterium ulcerans Infection in Mice

Buruli ulcer (BU), caused by infection with Mycobacterium ulcerans, is a chronic necrotizing human skin disease associated with the production of the cytotoxic macrolide exotoxin mycolactone. Despite extensive research, the type of immune responses elicited against this pathogen and the effector functions conferring protection against BU are not yet fully understood. While histopathological analyses of advanced BU lesions have demonstrated a mainly extracellular localization of the toxin producing acid fast bacilli, there is growing evidence for an early intra-macrophage growth phase of M. ulcerans. This has led us to investigate whether interferon-γ might play an important role in containing M. ulcerans infections. In an experimental Buruli ulcer mouse model we found that interferon-γ is indeed a critical regulator of early host immune defense against M. ulcerans infections. Interferon-γ knockout mice displayed a faster progression of the infection compared to wild-type mice. This accelerated progression was reflected in faster and more extensive tissue necrosis and oedema formation, as well as in a significantly higher bacterial burden after five weeks of infection, indicating that mice lacking interferon-γ have a reduced capacity to kill intracellular bacilli during the early intra-macrophage growth phase of M. ulcerans. This data demonstrates a prominent role of interferon-γ in early defense against M. ulcerans infection and supports the view that concepts for vaccine development against tuberculosis may also be valid for BU.     

The Burden of Leprosy in Cameroon: Fifteen Years into the Post-elimination Era

BackgroundCameroon achieved the elimination target of leprosy in 2000, and has maintained this status ever since. However, a number of health districts in the country continue to report significant numbers of leprosy cases. The aim of this study was to assess the burden of leprosy in Cameroon from 2000 to 2014.MethodsWe obtained and analysed using the new leprosy burden concept of analysis, leprosy surveillance data collected between 2000 and 2014 from the National Leprosy Control Programme.ConclusionThe leprosy prevalence and detection rates as well as the overall leprosy burden in Cameroon have dropped significantly between 2000 and 2014. However, a good number of health districts remain high-leprosy-burdened. The National Leprosy Control Programme should focus efforts on these health districts in the next coming years in order to further reduce the burden of leprosy in the country.     

A Sero-epidemiological Approach to Explore Transmission of Mycobacterium ulcerans

The debilitating skin disease Buruli ulcer (BU) is caused by infection with Mycobacterium ulcerans. While various hypotheses on potential reservoirs and vectors of M. ulcerans exist, the mode of transmission has remained unclear. Epidemiological studies have indicated that children below the age of four are less exposed to the pathogen and at lower risk of developing BU than older children. In the present study we compared the age at which children begin to develop antibody responses against M. ulcerans with the age pattern of responses to other pathogens transmitted by various mechanisms. A total of 1,352 sera from individuals living in the BU endemic Offin river valley of Ghana were included in the study. While first serological responses to the mosquito transmitted malaria parasite Plasmodium falciparum and to soil transmitted Strongyloides helminths emerged around the age of one and two years, sero-conversion for M. ulcerans and for the water transmitted trematode Schistosoma mansoni occurred at around four and five years, respectively. Our data suggest that exposure to M. ulcerans intensifies strongly at the age when children start to have more intense contact with the environment, outside the small movement range of young children. Further results from our serological investigations in the Offin river valley also indicate ongoing transmission of Treponema pallidum, the causative agent of yaws.     

Chronobiology of Nasal Chemosensitivity: Do Odor or Trigeminal Pain Thresholds Follow a Circadian Rhythm?

Odor and trigeminal pain thresholds were studied four timeseach at 24:00, 04:00, 08:00, 12:00, 16:00 and 20:00 h in randomizedorder on different days in five healthy male volunteers. Nocircadian rhythm of olfactory or trigeminal thresholds wereobserved. However, the variability of odor, but not pain thresholds,increased from 04:00 h (thresholds between 0.4 and 1.2 p.p.m.)to 16:00 h (thresholds between 0.1 and 2 p.p.m.). It is hypothesizedthat environmental influences contribute to this increase invariance. Chem. Senses 22: 593–598, 1997.