Homology-based repair induced by CRISPR-Cas nucleases in mammalian embryo genome editing

Recent advances in genome editing, especially CRISPR-Cas nucleases, have revolutionized both laboratory research and clinical therapeutics. CRISPR-Cas nucleases, together with the DNA damage repair pathway in cells, enable both genetic diversification by classical non-homologous end joining (c-NHEJ) and precise genome modification by homology-based repair (HBR). Genome editing in zygotes is a convenient way to edit the germline, paving the way for animal disease model generation, as well as human embryo genome editing therapy for some life-threatening and incurable diseases. HBR efficiency is highly dependent on the DNA donor that is utilized as a repair template. Here, we review recent progress in improving CRISPR-Cas nuclease-induced HBR in mammalian embryos by designing a suitable DNA donor. Moreover, we want to provide a guide for producing animal disease models and correcting genetic mutations through CRISPR-Cas nuclease-induced HBR in mammalian embryos. Finally, we discuss recent developments in precise genome-modification technology based on the CRISPR-Cas system.

Comparison of the Clinical Outcomes of Fresh Embryo Transfer with GnRH Agonist Long Protocol Versus GnRH Antagonist Protocol in Different Age Groups and Different Responders / 中山大学学报(医学科学版)

[Objective]To compare the clinical outcomes of fresh embryo transfer of the in vitro fertilization/intracytoplasmic sperm injection and embryo transfer(IVF/ICSI-ET)in different age groups as well as in different responders using gonadotropin-re-leasing hormone agonist(GnRH-a)long protocol or GnRH antagonist(GnRH-ant)protocol.[Methods]A retrospective analysis was performed on 737 IVF/ICSI cycles,including 386 cycles of GnRH-a long protocol(group A)and 351 cycles of GnRH-ant protocol (group B),from August 28,2015 to December 31,2016. Then all the cycles were divided into sub-groups by ages and retrieved oo-cyte numbers:group a1(15). The basic information of patients and clinical outcomes were compared.[Results](1)Comparable results were obtained from group A and group B in these following variables such as fertilization rate,normal fertilization rate,biochemical pregnancy rate and miscarriage rage. But the stimulation period,the total gonadotropin(Gn)dosage,estradiol(E2)level and endometrial thickness on the day of human chorionic gonadotropin(hCG)administration,number of oocytes retrieved and mature oocytes,ovarian hyperstimulation syn-drome(OHSS)rate,implantation rate and clinical pregnancy rate were significantly higher in group A than group B(P<0.05),and significantly higher cancellation rate of fresh embryo transfer was observed in group B(P<0.001).(2)When divided by ages,no mat-ter in sub-group a1 or sub-group a2,the implantation rate was slightly lower in GnRH-ant protocol than in GnRH-a long protocol, although they failed to reach significant difference(sub-group a1:32.6%vs 39.8%,P=0.067;sub-group a2:9.7%vs 17.9%,P=0.066). The clinical pregnancy rate was comparable using these two protocols in sub-group a1(54.8%vs 50.4%,P=0.429),but it was significantly lower by using GnRH-ant protocol than GnRH-a long protocol in sub-group a2(19.6%vs 39.1%,P=0.021).(3) When divided by numbers of oocytes retrieved,the implantation rate was significantly lower when using GnRH-ant protocol in sub-group b1(13.1%vs 26.0%,P=0.026),but we failed to observe significant differences in other two sub-groups. The clinical preg-nancy rates were comparable in all sub-groups ,whereas differed considerably in sub-group b1 (36.6% vs 19.3%,P = 0.056).[Conclusion]Overall,the implantation rate and clinical pregnancy rate were higher in GnRH-a long protocol than those in GnRH-ant protocol. Nevertheless,GnRH-ant protocol could reduce the dosage of Gn,shorten the treatment duration,and effectively reduce the occurrence of OHSS. There were similar pregnancy outcomes in two protocols for normal responders and high responders ,while for advanced patients or other poor responders,the implantation rate and clinical pregnancy rate were higher in GnRH-a protocol.

The prevalence and charateristics of carotid atherosclerosis among healthy middle-aged people in community / 中华老年医学杂志

Objective To investigate the prevalence and charateristics of carotid atherosclerosis among healthy middle-aged people of community. Methods Totally 1930 subjects aged 50 years and above were selected randomly from 10027 participants recruited during Phase 3 of the Guangzhou Biobank Cohort Study (GBCS).Common carotid artery intima-media thickness (CCA-IMT) and carotid plaques (CP) were measured by B-mode ultrasonography using ALT HDI 3000 mainframe with a high-resolution. Results The prevalences of CCA-IMT and CP in men were higher than women [41.5％(400/963)vs.16.2 (157/967),34.1％ (328/967) vs.13.8％ (133/967),both P＜0.001].The prevalence of CCA-1MT was higher with age increasing in either men or women in groups of 50-yrs,60-yrs and 70-79 yrs (all P＜0.001).The most of CP was cankerous spot (37.8％),secondly hard spot (24.9％),soft spot (22.1％) and the prevalence of flat spot was lowest (15.2％).The number of CP was not significantly different between the left and right side (51.0％ and 49.0％).The most common location of CP was bifurcations of carotid arteries (61.7 ％),next the common carotid artery (21.0％) and internal carotid artery (ICA) was lowest (17.3 ％).The prevalence of CP was 44.4％ (83/87) in women aged 50- yrs,it was higher than that in men 20.9％ (108/517).However,the prevalence of CP was 79.1％ (409/517) in men aged more than 60 yrs,higher than that in women (55.6％). Conclusions The carotid atherosclerosis is commonly encountered disease in the male elderly,and the most of CP was cankerous spot in bifurcations of carotid arteries

Acute fluoroacetamide poisoning with main damage to the heart / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To observe the heart damage in 10 patients with acute fluoroacetamide poisoning.</p><p><b>METHODS</b>Monitoring serum activities of myocardial enzymes [creatine kinase (CK), asparate aminotransferase (AST), lactate dehydrogenase(LDH) and hydroxybutyrate dehydrogenase(HBDH)] and recording ECG on these 10 patients were performed during the period of their hospitalization. In the mean while, 24 hour dynamic ECG were also recorded and analysed using GP7000L Holter.</p><p><b>RESULTS</b>(1) Urinary fluorine ion concentrations were increased in 9 patients before therapy and in all these 10 patients during therapeutic period. (2) The activities of serum CK in 2 patients and that of serum HBDH in one patient were increased before therapy. However, the serum activities of one or more than one myocardial enzymes were increased in all these 10 patients during therapeutic period. (3) Four patients had abnormal change of ECG before therapy and 5 patients during therapeutic period. (4) 24 hour dynamic ECG records showed that there were heart electrical alternans in 9 patients. One patient had wandering pacemaker and 6 patients had arythmia.</p><p><b>CONCLUSION</b>Fluoroacetamide may cause obvious heart damage, and also heart electrical alternation.</p>