Chromatin-to-nucleoprotamine transition is controlled by the histone H2B variant TH2B

The conversion of male germ cell chromatin to a nucleoprotamine structure is fundamental to the life cycle, yet the underlying molecular details remain obscure. Here we show that an essential step is the genome-wide incorporation of TH2B, a histone H2B variant of hitherto unknown function. Using mouse models in which TH2B is depleted or C-terminally modified, we show that TH2B directs the final transformation of dissociating nucleosomes into protamine-packed structures. Depletion of TH2B induces compensatory mechanisms that permit histone removal by up-regulating H2B and programming nucleosome instability through targeted histone modifications, including lysine crotonylation and arginine methylation. Furthermore, after fertilization, TH2B reassembles onto the male genome during protamine-to-histone exchange. Thus, TH2B is a unique histone variant that plays a key role in the histone-to-protamine packing of the male genome and guides genome-wide chromatin transitions that both precede and follow transmission of the male genome to the egg.     

Outbreak of Mycoplasma pneumoniae at a military academy

In 2019,an outbreak of Mycoplasma pneumoniae (M.pneumoniae) occurred at a military academy in China.The attack rate (10.08％,60/595) was significantly different among the units.High-intensity training and crowded environments to which cadets are exposed are the high risk factors for the outbreak of M.pneumoniae.In-time prevention and control measures effectively controlled the spread of the epidemic.     

Anti-CCL25 Antibody Prolongs Skin Allograft Survival by Blocking CCR9 Expression and Impairing Splenic T-Cell Function

Chemokines, by virtue of their ability to recruit immune cells into allografts, play critical roles in acute transplantation rejection. CCR9 and its ligand, CCL25, is one of the key regulators of thymocyte migration and maturation in normal and inflammatory conditions. Moreover, several studies have revealed that high expression of CCR9 and CCL25 participated in many kinds of diseases. However, the role of CCR9 in allograft rejection is still unclear. In this study, we established a murine skin transplantation model of acute rejection. Our findings showed that the proportion of CCR9-expressing T cells was significantly increased in the spleen of allotransplanted mice compared with syngeneic transplantation. Furthermore, expression of CCL25 in allograft was similarly increased. Neutralization of CCL25 by intravenous injection of anti-CCL25 monoclonal antibody significantly prolonged skin allograft survival, decreased the number of infiltrating cells, and simultaneously suppressed the chemotactic ability and the proliferation of the splenic T cells in response to allogeneic antigens. Finally, blockade of CCL25 also diminished the secretion of IFN-γ by splenic T cells. These studies indicated that CCR9/CCL25 was involved in acute transplantation rejection and anti-CCL25 strategies might be useful in preventing acute rejection.     

Secular change in height,sitting height and leg length in rural Oaxaca,southern Mexico: 1968–2000

Objective: To evaluate secular changes in height, sitting height and estimated leg length between 1968 and 2000 in residents in a rural Zapotec-speaking community in Oaxaca, southern Mexico.

Materials and methods: Height and sitting height were measured in school children 6–13 years (1968, 1978, 2000), in adolescents 13–17 years (1978, 2002) and adults 19–29 years (1978, 2000). Leg length was estimated as height minus sitting height. The sitting height/height ratio was calculated. Subjects were grouped by sex into four age categories: 6–9, 10–13, 13–17 and 19–29 years for analysis. The Preece–Baines Model I growth curve was fitted to cross-sectional means for 1978 and 2000.

Results: There were no differences between children 6–9 and 10–13 years in 1968 and 1978 with the exception of the sitting height ratio in girls 6–9 years. Children of both sexes 6–13 years and adolescent boys 13–17 years were significantly larger in the three dimensions in 2000 compared to 1978; adolescent girls differed only in height and sitting height. Adult males in 2000 were significantly taller with longer legs than those in 1978, but the samples did not differ in sitting height and the ratio. Adult females in 1978 and 2000 did not differ significantly in the three dimensions. Rates of secular change in height and sitting height between 1978 and 2000 were reasonably similar in the three age groups of male children and adolescents, but the rate for estimated leg length was highest in 10–13-year-old boys. Secular gains were smaller in adult males, but were proportionally greater in estimated leg length. Girls 6–9 and 10–13 years experienced greater secular gains in height, sitting height and estimated leg length than adolescent and young adult females, while secular gains and rates decreased from adolescent girls to young adult women. Ages of peak velocity for height, sitting height and estimated leg length declined in boys, while only ages of peak velocity for height and estimated leg length declined in girls.

Conclusions: There are major secular increases in height, sitting height and estimated leg length of children and adolescents of both sexes since 1978. Secular gains in height are of similar magnitude in boys and girls 6–13 years, but are greater in adolescent and young adult males than females. The secular increase in height of young adults of both sexes is smaller than that among adolescents. Estimated leg length accounts for about 60% of the secular increase in height in children of both sexes. Estimated leg length and sitting height contribute equally to the secular increase in height in adolescent boys, whereas estimated leg length accounts for about 70% of the secular increase in height in young adult males. Sitting height contributes about two-thirds of the secular increase in height in adolescent and young adult females.     

Autophagy-related proteins LC3 and Beclin-1 impact the efficacy of chemoradiation on esophageal squamous cell carcinoma

Autophagy is a bulk protein and organelle degradation process essential for cellular maintenance, cell viability and development. This study investigated the prognostic role of LC3 and Beclin-1, two autophagy-related proteins, in patients with locally advanced esophageal squamous cell carcinoma (ESCC) treated with definitive chemoradiation.     

Repetitive transcranial magnetic stimulation for lower extremity motor function in patients with stroke: a systematic review and network meta-analysis

Transcranial magnetic stimulation, a type of noninvasive brain stimulation, has become an ancillary therapy for motor function rehabilitation. Most previous studies have focused on the effects of repetitive transcranial magnetic stimulation(rTMS) on motor function in stroke patients. There have been relatively few studies on the effects of different modalities of rTMS on lower extremity motor function and corticospinal excitability in patients with stroke. The MEDLINE, Embase, Cochrane Library, ISI Science Citation Index, Physiotherapy Evidence Database, China National Knowledge Infrastructure Library, and ClinicalTrials.gov databases were searched. Parallel or crossover randomized controlled trials that addressed the effectiveness of rTMS in patients with stroke, published from inception to November 28, 2019, were included. Standard pairwise meta-analysis was conducted using R version 3.6.1 with the "meta" package. Bayesian network analysis using the Markov chain Monte Carlo algorithm was conducted to investigate the effectiveness of different rTMS protocol interventions. Network meta-analysis results of 18 randomized controlled trials regarding lower extremity motor function recovery revealed that low-frequency rTMS had better efficacy in promoting lower extremity motor function recovery than sham stimulation. Network meta-analysis results of five randomized controlled trials demonstrated that highfrequency rTMS led to higher amplitudes of motor evoked potentials than low-frequency r TMS or sham stimulation. These findings suggest that rTMS can improve motor function in patients with stroke, and that low-frequency rTMS mainly affects motor function, whereas high-frequency rTMS increases the amplitudes of motor evoked potentials. More highquality randomized controlled trials are needed to validate this conclusion. The work was registered in PROSPERO(registration No. CRD42020147055) on April 28, 2020.     

Molecular evidence for a clonal relationship between synchronous uterine endometrioid carcinoma and ovarian clear cell carcinoma: a new example of “precursor escape”?

Journal of Molecular Medicine - Synchronous endometrial and ovarian carcinomas (SEOCs) that share the same endometrioid histology are generally considered as the result of metastatic spread from...     

胸椎旁神经阻滞技术的研究进展

胸椎旁神经阻滞术(thoracic paravertebral block,TPVB)是将局麻药注入椎旁间隙进而产生同侧节段性躯体和交感神经阻滞的技术[1,2]。TPVB应用于脊柱、胸腹部急慢性疼痛的镇痛主要与胸椎旁间隙(thoracic paravertebral space,TPVS)的解剖结构有关。TPVS为位于胸椎两旁的楔形间隙,如图1所示[3],内含脂肪组织、脊神经根、肋间神经、胸神经背支、交通支、交感神经链和肋间动静脉等结构,其内侧界由椎体、椎间盘和椎间孔构成,向内经椎间孔与硬膜外间隙相连,外侧在肋横关节附近逐渐变细并延续为肋间隙。前缘为胸膜,后缘为肋横突上韧带,不同节段的上下边界由肋骨头、肋骨颈、横突以及肋横突韧带等分隔。关于TPVS的尾端边界有较大争议,部分学者认为腰大肌是TPVS的下边界[4],但其他研究发现注射剂可通过膈肌的内侧和外侧弧状韧带向腰丛和腹腔神经节扩散,并不存在尾端边界[5]。至今,还没有TPVS头端边界的相关描述。现将椎旁神经阻滞技术的种类、适应证和禁忌证、并发症等方面的研究综述如下。