[Determination of Perchloroethylene in blood by headspace gas chromatography-mass spectrometry].

Objective: To establish a method for determination of Perchloroethylene (PCE) in blood by headspace gas chromatography-mass spectrometry (HS/GC-MS) . Methods: From Dctober to December 2021, A total of 3 mL blood samples were taken into a 10 mL headspace bottle, after heated at 60 ℃ for 30 mins, PCE in the top air was separated by VF-WAXms capillary column and detected by GC-MS. The retention time and external standard method were used for qualitative and quantitative analysis of PCE in samples, respectively. Results: There was good linear relationship in the range of 5.09-200.17 µg/L. The linear correlation coefficient was 0.9993.The detection limit was 0.21 µg/L and the lower limit of quantitation was 0.70 µg/L. The recovery rates of samples with different concentrations were 95.3%-103.8%. The intra-batch relative standard deviations (RSD) were 3.2%-4.6%, and inter-batch RSD was 4.0%-6.1%. The samples can be stored at 4 ℃ for three days and at -20 ℃ for seven days. Conclusion: This method is proved to be simple, practical and highly sensitive, which is suitable for the determination of PCE in blood.

An observational study on the safety of COVID-19 vaccination in patients with myasthenia gravis.

OBJECTIVE: There is concern that the coronavirus disease (COVID-19) vaccine may trigger or worsen autoimmune diseases. The objective of this study was to determine the impacts of COVID-19 vaccination on symptom severity in patients with myasthenia gravis (MG). METHODS: A total of 106 enrolled patients with MG who were vaccinated against COVID-19 were followed up, and a questionnaire was used to document in detail the exacerbation of muscle weakness after vaccination and all other uncomfortable reactions after vaccination. Demographic, clinical characteristics, medication, and vaccination data were collected by follow-up interview. The main observation outcome was whether the MG symptoms of patients were exacerbated. The definition of exacerbation is according to the subjective feeling of the patient or a 2-point increase in daily life myasthenia gravis activity score relative to before vaccination, within 30 days after vaccination. RESULTS: Of 106 enrolled patients [median age (SD) 41.0 years, 38 (35.8%) men, 53 (50.0%) with generalized MG, 74 (69.8%) positive for acetylcholine receptor antibody, and 21 (19.8%) with accompanying thymoma], muscle weakness symptoms were stable in 102 (96.2%) patients before vaccine inoculation. Muscle weakness worsened in 10 (9.4%) people after vaccination, of which 8 patients reported slight symptom worsening that resolved quickly (within a few days). Two (1.9%) of patients showed serious symptom aggravation that required hospitalization. CONCLUSION: Our results suggest that inactivated virus vaccines against COVID-19 may be safe for patients with MG whose condition is stable. Patients with generalized MG may be more likely to develop increased muscle weakness after vaccination.

[Evaluation of the determination of hydrogen sulfide in the air of workplace by the detection tube method].

Objective: To evaluate the accuracy and applicability of detection tube method for quantitative detection of hydrogen sulfide in workplace air. Methods: In September 2021, the lower limit of quantification, accuracy, precision, environmental factors, interfering gases and other performance indicators of the method for determining hydrogen sulfide in the air of workplace were verified by the detection tube, and the results were compared with those of GB 11742-89 "Standard method for hygienic examination of hydrogen sulfide in air of residential areas-methylene blue spectrophotometric method" to evaluate the application effect of the detection tube method for quantitative detection of hydrogen sulfide in workplace air. Results: There was no significant difference in the results of 2.83 mg/m(3), 4.25 mg/m(3) and 17.00 mg/m(3) hydrogen sulfide concentration between the two methods (P>0.05) , but there was significant difference in the results of 8.50 mg/m(3) concentration (P<0.05) . The lower limit of quantification of hydrogen sulfide in workplace air was 2.83 mg/m(3), the accuracy was 96.0%-111.0%, and the precision was 0.70%-6.64%. Under the condition of 4 ℃, the measured results decreased by 3.39%-13.10%. When the humidity was 50%-80%, the relative error of the average measured value was -1.67%-4.44%. Interference gases that may exist in the workplace (including carbon dioxide, carbon monoxide, mercaptans, nitrogen oxides, sulfur dioxide, etc.) did not interfere with the results of the test tube. Conclusion: The accuracy and precision of the detection tube method meet the detection requirements. The method is simple, rapid and easy to be popularized, and can be used for the rapid detection of hydrogen sulfide gas concentration in the workplace.

[Analysis of clinical characteristics and related genetic variation of juvenile myasthenia gravis].

Objective: To analyze the clinical characteristics and related genetic variation of juvenile myasthenia gravis (MG) patients. Methods: We collected the clinical data of adolescent MG patients who were treated in the Department of Neurology of the First Affiliated Hospital of Sun Yat-sen University from June 2019 to May 2020. After obtaining the patient's informed consent, the blood samples were collected. The Whole Exome Sequencing (WES) was performed on peripheral blood samples. And use biological information software and SPSS 22.0 for data processing and result analysis. Results: According to the inclusion and exclusion criteria, 54 patients with juvenile MG were included, 28 males and 26 females. And the average age of onset was (3.79±0.89) years. Among the enrolled patients, there were 52 (96.3%) patients with ocular MG, the MG-ADL scores of 54 patients were (3.44±0.44) points, and the titer of AChR antibody was (5.88±2.45) nmol/L. Two patients had thymic hyperplasia, and 5 patients had a family history of MG.A total of 169 variant genes were found in 54 patients, of which TTN gene variants had the largest number, with a total of 17 variants (31.5%). In the TTN gene variant group, 7(41.2%) patients had eye fixation symptoms, and 4 (10.8%) patients in the non-mutation group had eye fixation symptoms. And The difference between the two groups was statistically significant (P=0.016). In addition, the synaptic nucleus envelope protein-1 (SYNE1) and the ryanodine receptor-1 (RYR1) gene variations were also found in 7 cases (13.2%), and no clear relationship between these gene variations and clinical manifestations of MG was found. Conclusions: The incidence of juvenile MG was preschoolers with no gender difference, and ocular MG was more common. The proportion of TTN gene variation in adolescent MG was higher, suggesting that this gene may be a potential therapeutic target for juvenile MG patients.

[Clinical characteristics and outcomes of myasthenia gravis patients with double positive antibodies against acetylcholine receptor and muscle-specific tyrosine kinase].

Objective: To investigate the clinical manifestations, treatment characteristics and outcomes of myasthenia gravis (MG) dually positive for anti-acetylcholine receptor antibody (AChR-Ab) and anti-muscle-specific tyrosine kinase antibody (MuSK-Ab). Method: MG patients hospitalized in the First Affiliated Hospital of Sun Yat-sen University from August 2017 to November 2020 were retrospectively collected. Thirty-four MuSK-Ab positive MG (MuSK-MG) patients, 11 double-antibodies positive MG (DP-MG) patients, and 80 AChR-Ab positive MG (AChR-MG) patients were included and allocated to three different groups. The clinical data of patients in the three groups were collected, and the differences of demographic characteristics, clinical manifestations and treatment outcomes between DP-MG patients and AChR-MG and MuSK-MG patients were analyzed. Result: The proportion of female and male patients in DP-MG group was 7/11 and 4/11 respectively, and the onset age of DP-MG was (41±27) years.The difference in gender distribution between DP-MG and AChR-MG groups was statistically significant (P<0.05). The proportion of extraocular muscle involvement in the DP-MG and MuSK-MG groups (8/11 and 52.9%) was lower than that in the AChR-MG group (83.8%), and the difference was statistically significant (P<0.05). The incidence of myasthenia crisis in DP-MG and MuSK-MG groups (54.5% and 61.8%) were higher than that in AChR-MG group (20.0%), with astatistically significant difference(P<0.05). The positive rate of neostigmine test in DP-MG and MuSK-MG groups(8/11 and 74.2%) were lower than that of AChR-MG group (96.8%), and the positive rate of low frequency repetitive nerve stimulation (RNS) in DP-MG group (5/10) was lower than that in AChR-MG group (85.1%), with statistically significant differences (all P<0.05). MuSK-Ab titer was positively correlated with the course of disease (r=0.466, P<0.05), and antibody titer decreased after symptom improvement (P<0.05). The response of patients in DP-MG and MuSK-MG groups to cholinesterase inhibitors (2/11 and 9.1%) was worse than that in the AChR-MG group (66.3%), and the incidence of side effects in the two groups (5/11 and 39.4%) was higher than that in the AChR-MG group (15.0%), with statistically significant differences (all P<0.05). There were 4 DP-MG patients underwent thymectomy, and the pathological results detected two cases of thymoma and two cases of thymic hyperplasia. Subsequent follow-up showed that 5 (5/11) DP-MG patients achieved minimal manifestation status or better status. Conclusion: The gender distribution, age of onset, pharmacological characteristics and electrophysiological examination of DP-MG patients were similar to those of MuSK-MG patients, but the severity of DP-MG patients was between that of AChR-MG and MuSK-MG patients.

Gender-specific SBNO2 and VPS13B as a potential driver of osteoporosis development in male ankylosing spondylitis.

To identify the critical genes and pathways that related to OP development in male AS patients, bioinformatic gene analysis and qRT-PCR validation were performed. SBNO2 and VPS13B were identified as the potential target for OP development, which may be valuable for the prevention of OP in male AS patients. INTRODUCTION: Osteoporosis (OP) is common in men with ankylosing spondylitis (AS). The specific pathogenesis of OP in AS, however, is still unclear. The present study attempted to identify potential genes associated with the development of OP in males with AS. METHODS: Gene expression profiles were downloaded from the GSE73754 and GSE35959 datasets from the Gene Expression Omnibus (GEO). Data from OsteoporosAtlas were downloaded as a supplement. Differentially expressed genes (DEGs) were determined with the limma package. The overlapping DEGs between male AS-related genes and OP-related genes were determined. The DEGs were validated by qRT-PCR in the blood samples of males with AS. Weighted gene co-expression network analysis (WGCNA) was utilized to establish a co-expression network to identify the hub genes. RESULTS: A total of 17 overlapping DEGs were identified; 6 genes in 17 overlapping DEGs were verified as the essential genes in the pathogenesis of OP in male AS by qRT-PCR analysis. After WGCNA, the modules of MEblue (> 0.6) and MEred (> 0.8) were screened out by the correlation analysis and were determined to function mainly in MAPK signaling pathway and osteoclast differentiation. Analysis of the two modules revealed VPS13B and SBNO2 as key genes due to the high degree of correlation. Both genes play an important role in bone metabolism regulation in male AS. Two hub genes MYD88 in MEblue and NCK1 in MEred with high degree of connectivity were selected. CONCLUSIONS: Gender-specific SBNO2 and VPS13B may be key genes involved in OP in male AS.

[To attach great importance to the identification of refractory myasthenia gravis].

Refractory myasthenia gravis is an intractable state during treatment. The common causes of refractory treatment in most patients include: overwork, malnutrition, infections, insomnia, cognitive and emotional disorders, and so on. Only targeting the poor curative effect from the surface of the intractable state caused indecisive decisions and is difficult to win a success. Therefore, identifying "refractory state" can not only see the essence through the phenomenon, but also apply the right medicine, thereby killing two birds with one stone.

[Characteristics of electromyography in 111 patients with generalized myasthenia gravis: a retrospective study].

Objective: To retrospectively analyze the characteristics of the electromyography (EMG) study in generalized myasthenia gravis (gMG) patients. Methods: A total of 111 gMG patients were enrolled. Patients were divided into two groups: 36 severe patients discontinuing pyridostigmine bromide (PB) for 8 hours were included in 8 h group, and 75 g MG patients discontinuing PB for at least 18 hours were included in>18 h group. The clinical information and EMG study data were collected and analyzed. Results: There were statistically significant differences in the initial location of the myasthenia muscle (P=0.027), the affected muscle detected by the EMG (P=0.015) and quantitative myasthenia gravis (QMG) score (P<0.01) between the two groups. Comparisons in each group revealed that the highest positive rate of low-frequency repetitive nerve stimulation (RNS) of facial in 8 h group and>18 h group was 94.4% and 60.0%, respectively. Comparisons between the two groups showed that the positive rate of low-frequency RNS in 8 h group was significantly higher than that in>18 h group (94.4% vs 70.7%, χ(2)=8.115, P=0.004). In particular, the positive rate of RNS in facial nerves and the extent of the amplitude decrease under different electrical stimulations (1 Hz, 3 Hz, and 5 Hz) were dramatically higher in the 8 h group (P<0.01). Conclusions: For gMG patients, the facial and accessory nerve detection can improve the positive rate of RNS. Different muscles had various sensitivity to PB, and orbicularis oculi muscle seemed the least sensitive muscle to PB. For suspect MG patients in severe condition, only discontinuing PB medication for 8 h before low-frequency RNS testing can avoid the deterioration and also obtain similar positive rate.

Antifungal activity of the bioactive substance from Bacillus atrophaeus strain HAB-5 and its toxicity assessment on Danio rerio.

The prevalence of pathogen inhibitors bacteria has motivate the study for antimicrobial compounds. Bioactive fungicide have always received considerable attention. A bacterial isolated strain HAB-5 showed antifungal activity against plant fungi. Based on morphological, physiological, biochemical and 16SrDNA sequence analysis, the strain was identified to be a Bacillus atrophaeus. This strain possessed a broad spectrum antifungal activity against various plant pathogenic fungi. Extraction of antifungal substance was performed and the crude extract had potent antifungal ability and showed great potential for swelling and inhibiting spore germination. This antifungal displayed heat stability and active in a wide pH range 5.0-10.0. Moreover no reduction was found in its activity after enzyme treatment. The toxicity test was evaluated in Danio rerio. The acute toxicity test indicated that the 24, 48, 72, 96h LC50 values of UMTLS to the zebrafish were 14.4, 13.8, 13.4, and 12.9%, respectively. Based on the results obtained in this study, antifungal substance was not toxic to zebra. Analyses of disease suppression showed that HAB-5 was effective to reduce the incidence of anthracnose symptoms on mango fruits, also prevent disease infection and protect tobacco seedling from Phytophtora nicotianae. The bioactive substance from Bacillus atrophaeus HAB-5 could be a candidate in the generation of new antifungal agents in crop.

[Establishment of DNA Genetic Marker Identification System for Plant Evidence].

OBJECTIVES: To establish a species identification system based on DNA genetic markers for plant evidence. METHODS: Two hundred common plants in Shanghai were collected and identified by morphological characteristics. The primers of gene segments rbcL, matK, and ITS were designed and amplified. The PCR amplicon was detected by agarose gel electrophoresis. After the sequencing, the universality and the identification capacity of the three markers were evaluated. RESULTS: The success rate of amplification was in order of rbcL （99.5%） > matK （92.5%） > ITS （86.0%）. The identification capacity of the combination of rbcL and matK was better than that of rbcL or matK, by which most plant species could be identified to the genus or higher. ITS was not suitable to be a unique marker because of its unstable result, but it still could be a powerful supplement. The identification capacity of the combination of rbcL, matK and ITS was higher than that of rbcL and matK, by which most plant species could be identified to the genus or lower. CONCLUSIONS: The identification system with the combination of rbcL, matK and ITS as markers has excellent universality for plant evidence, which can distinguish most plant species to the genus or lower.

[Correlation factors of 127 times pre-crisis state in patients with myasthenia gravis].

Objective: To investigate the clinical features of the Pre-Crisis State and analyze the correlated risk factors of Pre-Crisis State of myasthenia crisis. Methods: We included 93 patients with myasthenia gravis (MG) who experienced 127 times Pre-Crisis State between October 2007 and July 2016. Those patients were hospitalized in the MG specialize center, Department of Neurological Science, first Affiliated Hospital of Sun Yat-sen University. The information of the general situation, the clinical manifestations and the blood gas analysis in those patients were collected using our innovated clinical research form. Statistic methods were applied including descriptive analysis, univariate logistic analysis, multivariate correlation logistic analysis, etc. Results: (1)The typical features of MG Pre-Crisis State included: dyspnea (127 times, 100% not requiring intubation or non-invasive ventilation), bulbar-muscle weakness (121 times, 95.28%), the increased blood partial pressure of carbon dioxide (PCO(2)) (94 times, 85.45%), expectoration weakness (99 times, 77.95%), sleep disorders (107 times, 84.25%) and the infection (99 times, 77.95%). The occurrence of dyspnea in combination with bulbar-muscle weakness (P=0.002) or the increased blood PCO(2) (P=0.042) often indicated the tendency of crisis. (2) The MG symptoms which were proportion to the occurrence of crisis includes: bulbar-muscle weakness (P=0.028), fever (P=0.028), malnutrition (P=0.066), complications (P=0.071), excess oropharyngeal secretions (P=0.005) and the increased blood PCO(2) (P=0.007). The perioperative period of thymectomy would not increase the risk of crisis. Conclusions: Dyspnea indicates the occurrence of the Pre-Crisis State of MG. In order to significantly reduce the morbidity of myasthenia crisis, the bulbar-muscle weakness, the increased blood PCO(2), expectoration weakness, sleep disorders, infection & fever and excess oropharyngeal secretions should be treated timely.

[Characteristics of distribution and quantity of dendritic cells subtypes in hyperplastic thymus in patients with myasthenia gravis].

Objective: To investigate the characteristics of the distribution and amount of different subtypes of dendritic cell (DC) in myasthenia gravis(MG). Methods: We collected the thymic specimens from 32 patients who received thymoctomy because of cardiac surgery from January 2016 to December 2016 and selected 14 of them as normal control. Meantime, 61 MG patients who combined with thymic hyperplasia and received extended thymectomy were collected and selected 8 of them as experiment group.Immunohistochemical methods were used to label the two subtype DCs: plasmacytoid dendritic cell (pDC) and classical/conventional dendritic cell (cDC), to observe the distribution of these two DC subtypes in thymus and also quantify them in different thymus structures by image analysis software.Comparing with normal thymus of the same age, we intended to demonstrate the characteristics of distribution and density of DC subtypes in patients who had MG and hyperplastic thymus. Results: (1) We labeled pDC and cDC by staining with CD123 and CD11c.The two DC subtypes distributed in both cortex and medulla, and the majority gathered in medulla, the density of pDC in thymus cortex was (34±6)/mm(2)(n=14), the density of pDC in thymus medulla was (247±35)/mm(2)(n=14), the density of cDC in thymus cortex was (21±4)/mm(2)(n=14), the density of cDC in thymus medulla was (123±16)/mm(2) (n=14). (2) The density of pDC in thymus cortex and medulla of patients with MG was lower when compared with the normal group (the density of pDC in thymus cortex, [(39±10)/mm(2) vs (29±5)/mm(2)], the density of pDC in thymus medulla, [(279±48)/mm(2) vs (236±49)/mm(2)], but with no significant difference.There was no significant difference between the density of cDC in thymus cortex of patients with MG patients and normal people, however, the amount of cDC increases in medulla and the difference was statistically significant (P<0.05). (3) The density of cDC in thymus medulla (except for germinal center) was higher than normal people (110±18) /mm(2) vs (187±29/mm(2)), though the difference was not statistically significant (P=0.059 9). The density of cDC in the ectopic germinal center (GC) of MG patients increased obviously compared with that in thymus medulla [(203±44) /mm(2) vs (439±69)/mm(2)] and the difference was statistically significant (P<0.05). Conclusions: The density of cDC increases significantly in thymus medulla of MG patients, especially gathering around or in the ectopic GC. It indicates that cDC may play an important role in the formation of ectopic GC in the hyperplasia thymus, thus involves in the disease process.

[Expression of B cell transposition gene 3 in pancreatic ductal adenocarcinoma and its prognostic value].

Objective: To detect the expression of B cell transposition gene 3(BTG3) in pancreatic ductal adenocarcinoma(PDAC), and explore its relationship with postoperative recurrence and metastasis of tumor. Methods: Six self-paired frozen PDAC specimens and 3 normal pancreatic tissues from the Second Hospital of Jiaxing Affiliated to Jiaxing University were collected and the expression of BTG3 was detected by qPCR. Ten normal pancreatic tissues and 52 cases of PDAC tumor and paracarcinomatous tissues from the Second Hospital of Jiaxing Affiliated to Jiaxing University were collected from June 2009 to December 2016. The expression of BTG3 and relationship among BTG3 and clinicopathological characteristics of PDAC and patients' prognosis were detected and analyzed using immunohistochemistry.χ(2) test, Kaplan-Meier method and Cox regression model were used to analyzed the data. Results: The results of qPCR showed that expression level of BTG3 in PDAC (0.63±0.17) was lower significantly than that in paracarcinomatous (0.96±0.04) and normal tissues (1.00)(t=4.673, 5.502; both P<0.05). Immunohistochemistrv showed that BTG3 mainly expressed in the cytoplasm.The high expression rate of BTG3 in PDAC tumor tissues was 25.0%(13/52), which was remarkably lower than that in paracarcinomatous tissues(65.4%) and normal liver tissues(7/10)(χ(2)=17.120 and 5.849, both P<0.05). The low expression of BTG3 in PDAC was correlated with primary tumor, and TNM stage(χ(2)=7.704, P=0.006; U=154.000, P=0.018, respectively). Survival analysis showed that disease free survival rate of patients with low expression of BTG3 was significantly less than that with high expression(χ(2)=192.493, P<0.01). The Cox multivariate analysis demonstrated that low expression of BTG3 was independent risk factors for disease free survival in patients with PDAC after a curative resection(RR=3.366, 95%CI: 1.040-10.889, P=0.043). Conclusion: BTG3 may be involved in the occurence and development of tumor, and its low expression may be associated with poor prognosis in patients with PDAC.

Is the optimal intervention policy UC superior to the suboptimal policy MFPT over inferred probabilistic Boolean network models?

A salient problem in translational genomics is the use of gene regulatory networks to determine therapeutic intervention strategies. Theoretically, in a complete network, the optimal policy performs better than the suboptimal policy. However, this theory may not hold if we intervene in a system based on a control policy derived from imprecise inferred networks, especially in the small-sample scenario. In this paper, we compare the performance of the unconstrained (UC) policy with that of the mean-first-passage-time (MFPT) policy in terms of the quality of the determined control gene and the effectiveness of the policy. Our simulation results reveal that the quality of the control gene determined by the robust MFPT policy is better in the small-sample scenario, whereas the sensitive UC policy performs better in the large-sample scenario. Furthermore, given the same control gene, the MFPT policy is more efficient than the UC policy for the small-sample scenario. Owing to these two features, the MFPT policy performs better in the small-sample scenario and the UC policy performs better only in the large-sample scenario. Additionally, using a relatively complex model (gene number N is more than 1) is beneficial for the intervention process, especially for the sensitive UC policy.

Cancer Evolution-Development: experience of hepatitis B virus-induced hepatocarcinogenesis.

Here, we present the basic concept and theoretical framework of a scientific hypothesis called Cancer Evolution-Development ("Cancer Evo-Dev"), based on our recent studies of the molecular mechanisms by which chronic infection with the hepatitis B virus induces hepatocarcinogenesis, together with related advances in that field. Several aspects central to our hypothesis are presented: ■ Immune imbalance-caused by the interaction of genetic predispositions and environmental exposures such as viral infection-is responsible for the maintenance of chronic non-resolving inflammation. Non-resolving inflammation promotes the occurrence and progression of cancers, characterized by an evolutionary process of "mutation-selection-adaptation" for both viruses and host cells.■ Under a microenvironment of non-resolving inflammation, proinflammatory factors promote mutations in viral or host genomes by transactivation of the expression of cytidine deaminases and their analogues. Most cells with genomic mutations and mutated viruses are eliminated in the competition for survival in the inflammatory microenvironment. Only a small percentage of the mutated cells that alter their survival signal pathways and exhibit the characteristics of "stem-ness" can survive and function as cancer-initiating cells.■ Cancers generally develop with properties of "backward evolution" and "retro-differentiation," indicating the indispensability of stem-like signal pathways in the evolution and development of cancers. The hypothesis of Cancer Evo-Dev not only lays the theoretical foundation for understanding the mechanisms by which inflammation promotes the development of cancers, but also plays an important role in specific prophylaxis, prediction, early diagnosis, and targeted treatment of cancers.

Associations of single nucleotide polymorphisms in candidate genes with the polled trait in Datong domestic yaks.

The domestic yak (Bos grunniens) is an iconic symbol of animal husbandry at high altitudes. Yaks exhibit unique external characteristics including long hair and large horns. However, hornless yaks can be found in different breeds and different populations. The hornless trait is also known as polled, and the POLL locus has been fine-mapped to chromosome 1 in cattle (Bos taurus), although the underlying genetic basis of the polled trait is still unclear in the yak. Thus, we performed an association study to identify the genetic polymorphisms responsible for the polled trait in the yak. Fifty polled Datong domestic yaks and 51 horned individuals were selected randomly from a huge herd and were used as the case and control groups respectively for the association analysis. Twelve genes located in the candidate region of the POLL locus in cattle were used as references to detect DNA polymorphisms related to yak polledness, which were analyzed by sequencing and a high-resolution melting test. We applied Fisher's exact test and haplotype analysis to show that a 147-kb segment that included three protein-coding genes C1H21orf62, GCFC1 and SYNJ1 was the most likely location of the POLL mutation in domestic yaks.

Clinical features of myasthenia gravis in southern China: a retrospective review of 2,154 cases over 22 years.

The objectives of the study are to study the clinical features of myasthenia gravis in southern China. A retrospective study was carried out on all patients who were diagnosed with myasthenia gravis at the First Affiliated Hospital of Sun Yat-sen University during 1987-2009. Of the 2,154 myasthenia gravis patients, the gender ratio (male:female) was 1:1.15. The median age at onset was 18 years. There was a single peak distribution of age at onset, and 44.8 % were children (≤ 14 years) at first onset. 1,766 patients (82.0 %) only had ocular symptoms at onset. 1,451 patients (67.4 %) were classified as Osserman grade I. 250 unselected patients received anti-acetylcholine receptor antibodies test, in which only 51.2 % were positive. Computed tomography scan/magnetic resonance Imaging of chest were done in 1,354 patients, of which 899 patients (66.4 %) had thymic hyperplasia and 201(14.8 %) had thymoma. There were 150 patients (7.0 %) with myasthenia gravis combined with other autoimmune diseases, in which hyperthyroidism was most common (84 %). 189 (8.8 %) patients experienced 267 episodes of crisis. The rate of family myasthenia gravis was 1.6 % (35/2,154). In conclusion, the clinical features and demography of myasthenia gravis patients in this study are significantly different from prior studies on other regions and ethnic groups.

A genome-wide SNP scan reveals two loci associated with the chicken resistance to Marek's disease.

Marek's disease (MD) is a neoplastic disease in chickens, caused by the Marek's disease virus (MDV). To investigate host genetic resistance to MD, we conducted a genome-wide association study (GWAS) on 67 MDV-infected chickens based on a case and control design, including 57 susceptible chickens in the case group and 10 resistant chickens as controls. After searching 38 655 valid genomic markers, two SNPs were found to be associated with host resistance to MD. One SNP, rs14527240, reaching chromosome-wide significance level (P < 0.01) was located in the SPARC-related modular calcium-binding 1 (SMOC1) gene on GGA5. The other one, GGaluGA156129, reaching genome-wide significance (P < 0.05), was located in the protein tyrosine phosphatase, non-receptor type 3 (PTPN3) gene on GGA2. In addition, expression patterns of these two genes in spleens were detected by qPCR. The expression of SMOC1 was significantly up-regulated (P < 0.05), whereas the expression of PTNP3 did not show significance when the case group was compared with the control group. Up-regulation of SMOC1 in susceptible spleens suggests its important roles in MD tumorigenesis. This is the first study to investigate MD-resistant loci, and it demonstrates the power of GWASs for mapping genes associated with MD resistance.

Association of novel single-nucleotide polymorphisms of the vascular endothelial growth factor-A gene with high-altitude adaptation in yak (Bos grunniens).

Vascular endothelial growth factor-A gene (VEGF-A) is a key regulator of angiogenesis and an endothelial cell mitogen that plays an important role in high-altitude adaptation. In this study, we detected 2 novel single-nucleotide polymorphisms (SNPs) of VEGF-A by screening for genetic variation in 700 individuals of 3 domestic Chinese yak breeds--namely Gannan (GN), Datong (DT), and Tianzhu white (TZW)--using polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing techniques. GN and DT yaks live at high altitude and TZW yaks live at low altitude on the Qinghai-Tibetan Plateau. SNP g.8430T>C is located in intron 4 of VEGF-A. SNP g.14853G>A is located in the 3' untranslated region of VEGF-A. Frequencies of the GA and AA genotypes and the A allele of SNP g.14853G>A observed in GN and DT yaks were significantly higher than that in TZW yaks (P < 0.01). No significant difference among the breeds was observed for SNP g.8430T>C. The frequency of haplotype TA was significantly higher (P < 0.01), whereas the frequency of TG (P < 0.01) was significantly lower in GN and DT yaks compared with that in TZW yaks. The 2 SNPs were in moderate linkage disequilibrium in GN and DT yaks, but not in TZW yaks. The fixation index (FST) pairwise value was significantly different among the breeds studied. The neutral test result indicated that the region between the 2 SNPs may have been subjected to positive or balancing selection, and the high-altitude hypoxia environment might be the main determinant for selection. These results suggest that VEGF-A might contribute to the high-altitude adaptability of yak.