RÉSUMÉ
ObjectiveIn recent years, the negative impact of microgravity on astronauts’ nervous systems has received widespread attention. The repetitive transcranial magnetic stimulation (rTMS) technology has shown significant positive effects in the treatment of neurological and psychiatric disorders. The potential benefits of combined frequency stimulation (CFS) which combines different frequency stimulation patterns in ameliorating neurological dysfunctions induced by the microgravity environment, still require in-depth investigation. Exploring the therapeutic effects and electrophysiological mechanisms of CFS in improving various neurological disorders caused by microgravity holds significant importance for neuroscience and the clinical application of magnetic stimulation. MethodsThis study employed 40 C57BL/6 mice, randomly divided into 5 groups: sham group, hindlimb unloading (HU) group, 10 Hz group, 20 Hz group, and combined frequency stimulation (10 Hz+20 Hz, CFS) group. Mice in all groups except the sham group received 14 d of simulated microgravity conditions along with 14 d of repetitive transcranial magnetic stimulation. The effects of CFS on negative emotions and spatial cognitive abilities were assessed through sucrose preference tests and water maze experiments. Finally, patch-clamp techniques were used to record action potentials, resting membrane potentials, and ion channel dynamics of granule neurons in the hippocampal dentate gyrus (DG) region. ResultsCompared to the single-frequency stimulation group, behavioral results indicated that the combined frequency stimulation (10 Hz+20 Hz) significantly improved cognitive impairments and negative emotions in simulated microgravity mice. Electrophysiological experiments revealed a decrease in excitability of granule neurons in the hippocampal DG region after HU manipulation, whereas the combined frequency stimulation notably enhanced neuronal excitability and improved the dynamic characteristics of voltage-gated Na+ and K+ channels. ConclusionThe repetitive transcranial magnetic stimulation with combined frequencies (10 Hz+20 Hz) effectively ameliorates cognitive impairments and negative emotions in simulated microgravity mice. This improvement is likely attributed to the influence of combined frequency stimulation on neuronal excitability and the dynamic characteristics of Na+ and K+ channels. Consequently, this study holds the promise to provide a theoretical basis for alleviating cognitive and emotional disorders induced by microgravity environments.
RÉSUMÉ
<p><b>OBJECTIVE</b>To improve the accuracy of the diagnosis of the disease on the basis of the clinical features and genetic characteristics of patients with Silver Russell syndrome (SRS).</p><p><b>METHOD</b>Patients diagnosed with SRS by Price criteria in 2006 to 2011 were reviewed for their clinical manifestations, physical signs, laboratory examinations and treatments.</p><p><b>RESULT</b>Twenty cases with SRS were 0.08-12.17 yr old. Fifteen were male and 5 were female. The clinical characteristics included more than 80% of cases had postnatal growth retardation 100% (20/20), craniofacial dysmorphism 100% (20/20), small for gestation age 95% (19/20), asymmetry and thinning of the face and/or limbs 90% (18/20), fifth finger clinodactyly 80% (16/20), BMI < -2 SDS 80% (16/20). Their height was obviously lagging behind in the bone age. HD SDS/average of bone retardation was 3.08. The two patients with the chief complaint of external genital abnormalities would have aggressive surgical treatment and they did not use the growth hormone (GH) treatment. Only six patients had used the GH treatment. GH treatment at a dose of 0.1 IU/(kg·d) used in 2 cases achieved a growth velocity (GV) 8 - 11 cm/yr but in another 2 cases < 5 cm/yr. In genetic study, 6 patients were found to have 11p15 low methylation, 1 had low and high methylation, 1 had duplication, no relation between clinical and methylation of 11p15 was found.</p><p><b>CONCLUSION</b>There were great variations of clinical features in SRS characterized by small for gestation age and/or postnatal growth retardation, craniofacial dysmorphism, asymmetry of the face and/or limbs or ultrafine limbs, fifth finger clinodactyly. Severely low BMI was seen and height was obviously lagging behind in the bone age. The findings of laboratory tests and imaging of SRS were not specific. Some of SRS had 11p15 imprinting defects. The treatment of SRS is mainly symptomatic.</p>