Somatosensory cortectomy induces motor cortical hyperexcitability and scoliosis: an experimental study in developing rats

Background contextDysfunctions in sensorimotor integration, reminiscent to those described in idiopathic dystonia, have been found in idiopathic scoliosis (IS) and might be involved in its pathogenesis. Studying the effects of experimental disruption of sensory cortex may shed further insight into the etiopathology of IS.PurposeTo evaluate whether disruption of central sensorimotor integration through partial ablation of the somatosensory cortex leads to scoliosis in developing rats and to describe the effects of such an intervention on motor cortico-cortical inhibition and facilitation.MethodsFifty Wistar rats aged 3 weeks were used in the study. Twenty-four rats underwent craniotomy and electrocoagulation of the sensory cortex (PAR1) in the right hemisphere. A second group of 16 rats underwent a sham operation with craniotomy but no electrocoagulation. A third group of 10 rats was used as intact controls. Four weeks after surgery, motor cortical excitability was assessed with paired-pulse electrical cortical stimulation. Neurologic and behavioral examinations were completed serially, and 10 weeks after surgery, X-ray examinations were performed in anesthetized rats to assess spinal curvature. Electromyographic recordings of paravertebral muscle activity were performed in waking rats. At the end of the study, rats were sacrificed, and histologic examinations of brain tissue were performed to confirm the extent of the lesion. A grant from a Government Health Research Fund without salaries assignment financed the study.ResultsAlmost half of the animals with somatosensory cortectomy (46%) developed scoliosis, with an average Cobb angle of 23±8°. None of the animals in the sham or control groups developed scoliosis. Despite cortical lesions, no motor or behavioral deficits were apparent in the experimental group, and cortectomized rats were neurologically indistinguishable from sham or control animals, except for the presence of scoliosis. Cortico-cortical inhibition was significantly reduced in the hemisphere of scoliotic concavity in the cortectomized group but was normal in the other groups.ConclusionsThese findings indicate that altered sensorimotor integration may cause scoliosis without noticeable motor impairment. Reduced cortico-cortical inhibition was observed in cortectomized rats. This finding is consistent with results in adolescents with IS and suggests that alteration of cortical hemispheric balance of sensorimotor integration may play an important role in the pathogenesis of IS.     

Molecular characterization,serotyping, and antibiotic susceptibility profile of Leptospira interrogans serovar Copenhageni isolates from Brazil

Leptospira interrogans serogroup Icterohaemorrhagiae is the major serogroup infecting humans worldwide, and rodents and dogs are the most significant transmission sources in urban environments. Knowledge of the prevalent serovars and their maintenance hosts is essential to understand the epidemiology of leptospirosis. In this study, 20 Leptospira isolates were evaluated by pulsed-field gel electrophoresis (PFGE), variable number tandem-repeat analysis (VNTR), serotyping, and determination of antimicrobial resistance profile. Isolates, originated from bovine, canine, human, and rodent sources, were characterized by microscopic agglutination test with polyclonal and monoclonal antibodies and were identified as L. interrogans serogroup Icterohaemorrhagiae serovar Copenhageni. MICs of antimicrobials often used in veterinary medicine were determined by broth microdilution test. Most of tested antibiotics were effective against isolates, including penicillin, ampicillin, and ceftiofur. Higher MIC variability was observed for fluoroquinolones and neomycin; all isolates were resistant to trimethoprim/sulfamethoxazole and sulphadimethoxine. Isolates were genotyped by PFGE and VNTR; both techniques were unable to discriminate between serovars Copenhageni and Icterohaemorrhagiae, as expected. PFGE clustered all isolates in 1 pulsotype, indicating that these serovars can be transmitted between species and that bovine, rodent, and dogs can maintain them in the environment endangering the human population.     

Hypnotherapy of sexual impotence

A sleep-induction procedure requiring manual response to a repetitive auditory signal was administered to 52 Ss who had clear alpha activity in their waking EEG and whose hypnotizability was known. The occurrence of sleep was defined by physiological, behavioral, and subjective criteria. Neither the tendency to develop EEG sleep nor the ability of some Ss to respond while in EEG sleep was related to hypnotizability. Hypnotizability was related to a type of dissociation between EEG sleep and both behavioral and subjective sleep shown by 5 Ss, all highly hypnotizable.     

Bacterial Vaginosis in the Context of Lichen Sclerosus in a Prepubertal Girl

Group A beta‐hemolytic streptococcus cause most vulvovaginal infections seen in prepubertal girls. Bacterial vaginosis is a common cause of abnormal vaginal discharge in women of childbearing age but is rare in children. Data are insufficient to suggest that bacterial vaginosis is an exclusively sexually transmitted disease. We report a 10‐year‐old girl with no history or suspicion of sexual abuse who developed bacterial vaginosis in the context of a lichen sclerosus being treated with tacrolimus ointment. Secondary bacterial infection in lichen sclerosus is uncommon. We speculate that the immunosuppressive effect of topical tacrolimus could have triggered the infection.