New Mutants of Epsilon Toxin from Clostridium perfringens with an Altered Receptor-Binding Site and Cell-Type Specificity

Epsilon toxin (Etx) from Clostridium perfringens is the third most potent toxin after the botulinum and tetanus toxins. Etx is the main agent of enterotoxemia in ruminants and is produced by Clostridium perfringens toxinotypes B and D, causing great economic losses. Etx selectively binds to target cells, oligomerizes and inserts into the plasma membrane, and forms pores. A series of mutants have been previously generated to understand the cellular and molecular mechanisms of the toxin and to obtain valid molecular tools for effective vaccination protocols. Here, two new non-toxic Etx mutants were generated by selective deletions in the binding (Etx-ΔS188-F196) or insertion (Etx-ΔV108-F135) domains of the toxin. As expected, our results showed that Etx-ΔS188-F196 did not exhibit the usual Etx binding pattern but surprisingly recognized specifically an O-glycoprotein present in the proximal tubules of the kidneys in a wide range of animals, including ruminants. Although diminished, Etx-ΔV108-F135 maintained the capacity for binding and even oligomerization, indicating that the mutation particularly affected the pore-forming ability of the toxin.     

Changes at the CYP2C locus and disruption of CYP2C8/9 linkage disequilibrium in patients with essential tremor

To identify low-penetrance genes related to sporadic essential tremor (ET) at the CYP2Clocus, located in chromosome 10 q23.33. Leukocytary DNA from 200 ET patients and a control group of 300 unrelated healthy individuals with known CYP2C19 genotypes was studied for common CYP2C8 and CYP2C9 allelic variants by using amplification-restriction analyses. Patients with ET showed the following differences compared with healthy subjects: a 1.6-fold reduction in the frequency for CYP2C8*3 (p=0.006), a 1.35-fold reduction of CYP2C9*2 (p=0.05) and a 1.52-fold reduction in the frequency for CYP2C9*3 (p=0.07). The frequency for patients with ET carrying at least one defective allele was 1.33-fold reduced as compared with healthy subjects (p=0.002). In addition, a disruption of the CYP2C8*3/CYP2C9*2 linkage disequilibrium was observed in ET patients, with a 2.1-fold reduction in the percentage for carriers of the haplotype CYP2C8*3 plus CYP2C9*2 in ET patients (p=0.0001). These findings were independent of gender, age, age of onset, or clinical symptoms. These results suggest that alterations at the CYP2C gene locus are associated with the risk for ET.     

Acupuncture in patients with acute low back pain: A multicentre randomised controlled clinical trial

Reviews of the efficacy of acupuncture as a treatment for acute low back pain have concluded that there is insufficient evidence for its efficacy and that more research is needed to evaluate it. A multicentre randomized controlled trial was conducted at 4 primary-care centres in Spain to evaluate the effects of acupuncture in patients with acute nonspecific low back pain in the context of primary care. A total of 275 patients with nonspecific acute low back pain (diagnosed by their general practitioner) were recruited and assigned randomly to 4 different groups: conventional treatment either alone or complemented by 5 sessions over a 2-week period of true acupuncture, sham acupuncture, or placebo acupuncture per patient. Patients were treated from February 2006 to January 2008. The primary outcome was the reduction in Roland Morris Disability Questionnaire scores of 35% or more after 2weeks' treatment. The patients in the 3 types of acupuncture groups were blinded to the treatments, but those who received conventional treatment alone were not. In the analysis adjusted for the total sample (true acupuncture relative risk 5.04, 95% confidence interval 2.24-11.32; sham acupuncture relative risk 5.02, 95% confidence interval 2.26-11.16; placebo acupuncture relative risk 2.57 95% confidence interval 1.21-5.46), as well as for the subsample of occupationally active patients, all 3 modalities of acupuncture were better than conventional treatment alone, but there was no difference among the 3 acupuncture modalities, which implies that true acupuncture is not better than sham or placebo acupuncture.