Failure to Identify Somatic Mutations in Monozygotic Twins Discordant for Schizophrenia by Whole Exome Sequencing / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Schizophrenia (SCZ) is a severe, debilitating, and complex psychiatric disorder with multiple causative factors. An increasing number of studies have determined that rare variations play an important role in its etiology. A somatic mutation is a rare form of genetic variation that occurs at an early stage of embryonic development and is thought to contribute substantially to the development of SCZ. The aim of the study was to explore the novel pathogenic somatic single nucleotide variations (SNVs) and somatic insertions and deletions (indels) of SCZ.</p><p><b>METHODS</b>One Chinese family with a monozygotic (MZ) twin pair discordant for SCZ was included. Whole exome sequencing was performed in the co-twin and their parents. Rigorous filtering processes were conducted to prioritize pathogenic somatic variations, and all identified SNVs and indels were further confirmed by Sanger sequencing.</p><p><b>RESULTS</b>One somatic SNV and two somatic indels were identified after rigorous selection processes. However, none was validated by Sanger sequencing.</p><p><b>CONCLUSIONS</b>This study is not alone in the failure to identify pathogenic somatic variations in MZ twins, suggesting that exonic somatic variations are extremely rare. Further efforts are warranted to explore the potential genetic mechanism of SCZ.</p>

Investigations on prevalence and risk factors of visual hallucination in patients with Parkinson' s disease / 上海第二医科大学学报

Objective To investigate the prevalence and characteristics of visual hallucination among patients with Parkinson's disease (PD), and analyse the potential risk factors. Methods One hundred and twenty-eight patients with PD were administered self-prepared visual hallucination questionnaires, and prevalence of visual hallucination was surveyed. The differences in sex, age, disease duration, Mini Mental State Exam (MMSE) scores, Hoehn & Yahr stage, types of medicine used and levodopa equivalent doses (LDE) were compared between the patients with visual hallucination and those without visual hallucination. The prevalence of rapid eye movement sleep behavior disorder (RBD) was investigated in patients with visual hallucination. Results Eighteen patients (14.06%) experienced visual hallucination, among whom 10 (55.56%) experienced visual hallucination no less than one time per day, 11 (61.11%) "saw" the shadow of human figure and 15(83.33%)were complicated with RBD. There were significant differences in MMSE scores, Hoehn & Yahr stage, female proportion and usage of dopamine agonists between patients with visual hallucination and those without visual hallucination(P<0.05). Conclusion Visual hallucination is a common non-motor symptom among patients with PD, and cognitive function, disease severity and usage of dopamine agonista may be related to visual hallucination.

The sinus node itself also plays a role in heart rate slowing down during postnatal development / 生理学报

The slowing down mechanism of heart rate during growth of the body after birth was studied in isolated rabbit heart and sinus node (SN) preparation with Langendorff perfusion method, conventional microelectrode recording and perforated patch for recording pacemaker current I(f). The radioimmunoassay was also used to measure the concentration of cAMP within SN cells. The results indicate that without the influence of nervous and humoral factors, the spontaneous heart rate would also become slower as the rabbit grew older, which is due to the decrease of spontaneous depolarized rate of phase 4 in SN cells. The negative directed shift of the threshold potential of I(f) and the decrease in cAMP concentration within SN cells may be responsible for the phenomenon. The results obtained suggest that besides the nervous and humoral factors which influence the heart rate, the changes in automaticity of SN cell itself may take part in the slowing down process as the body grows up.

Studying the mechanism of heart rate slowing down after birth by the method of HRV power spectrum analysis / 中国应用生理学杂志

<p><b>AIM</b>To explore the neurological mechanism of heart rate slowing down after birth and to investigate if the heart itself participates in the process.</p><p><b>METHODS</b>With the method of HRV power spectrum analysis, the regulatory mechanisms of autonomic nerves over heart rate were studied on different age groups of human beings and rabbits. Similar experiments were carried out on isolated perfused rabbit hearts in order to study if the heart itself were involved in the process of heart rate slowing down as they grew up.</p><p><b>RESULTS</b>The ratio of parasympathetic tone to sympathetic one is significantly increased as a child or rabbit grows up while the heart rate becomes slower. The spontaneous beating of isolated rabbit heart also slows down as the rabbit becomes older.</p><p><b>CONCLUSION</b>Both of the nerve factor and heart itself are involved in the process of slowing down of heart rate as a child grows up.</p>