Objective To analyze and evaluate the characteristics of enzyme kinetics of CTX-M-14 type extended-spectrum β-lactamase(ESBL) with Pro167 residue substitution. Methods By molecular cloning and PCR techniques, CTX-M-14 gene was directionally cloned into plasmid pET28a( + ) from a clinical E. coli isolate and formed an expression vector to transform competent E. coli BL21 (DE3 ). Prol67 residue substitutions of P167G, P167Q, P167S and P167T were introduced to CTX-M-14 by site-directed muta-genesis based on overlap extension PCR with the former recombinant plasmid as PCR template, respectively.The wild-type CTX-M-14, recombinant CTX-M-14 protein and its variants were expressed and purified, then their steady-state kinetic parameters (Kcat, Km and Kcat/Km ) against β-lactam antibiotics were determined.Results The kinetic parameters of wild-type and recombinant CTX-M-14 had no statistically significant differences (P>0.1). The 1/Km, Kcat and Kcat/Km values of P167S variant against ceftazidime were 16-fold, 2.87-fold and 43.6-fold higher than those of recombinant CTX-M-14, respectively, and the Kcat/Km value of P167S variant against penicillin, ampicillin, cefazolin, cefuroxime, ceftriaxone, cefotaxime decreased( < 0.05). Compared with the kinetic parameters of recombinant CTX-M-14, the kinetic parameters of P167T variant against ceftazidime had no significant change, but the Kcat values of P167Q and P167G variants decreased dramatically(P<0.01). Conclusion There was no difference between the enzyme activities of wild-type and recombinant CTX-M-14. P167S variant could not only promote the enzyme affinity of CTX-M-14 to ceftazidime but also improve the conversion rate of enzyme-substrate complex in the ceftazidime hydrolysis. The comparison of the kinetic parameters of CTX-M-14 and its variants with Pro167 residue substitution showed that the increased activity of CTX-M ESBL variants against ceftazidime could not be simply explained with the enlarged cavity in active site that may be caused by the replacement of Pro167 residue by smaller amino acids.

ObjectiveTo report the results of preventive control program of severe thalassemias in Zhuhai City of Guangdong Province from 1998 to 2010.MethodsAs the guide centre of marriage and childbearing and the greatest maternity hospital in Zhuhai City of Guangdong Province,Zhuhai Municipal Maternity and Child Healthcare Hospital constructed the genetic screening network for thalassemias testing and referred for follow-up and for genetic counseling.The couples for premarital medical examination or regular healthcare examination in pregnancy were enrolled to this preventive control program.A conventional strategy of screening for heterozygote was used to identify the α- and β-thalassemia traits in women and their spouses according to the standard procedures of hematological phenotype analysis which was recommended by Thalassemia International Federation (T IF).Then those suspected couples at risk were diagnosed for α- and β-thalassemia by PCR-based DNA assays.The couples at risk for severe thalassemias were counseled and offered prenatal diagnosis and termination of pregnancy in case of an affected fetus in the rights of consent and of option voluntarily.ResultsFrom January 1998 to December 2010,85 522 brides and grooms-to-be for premarital screening and 41 503 pregnant women in addition to 14 141 partners for prenatal screening were recorded,the covering rates of premarital screening and prenatal screening in the city were 92.698％ (from 1998 to 2003) and 27.667％ (from 2004 to 2010),respectively.Totally 10 726 cases were found to be the carriers of thalassemias,with 7393 for o-thalassemia (5.237％,7 393/141 166) and 3333 for β-thalassemia (2.361％,3 333/141 166).A total of 257 couples at-risk for severe thalassemias were detected including 190 for α-thalassemia and 67 for β-thalassemia.Among them,251 (97.7％,251/257) couples were performed prenatal diagnosis.During the preventive control program,a total of 72 fetuses with severe thalassemias including hemoglobin H disease were voluntarily terminated.In Zhuhai City,the average annual birth rate of fetuses with severe thalassemia was declined by 32.9％ (49/149).ConclusionsThis study has reduced effectively birth rate of perinatal infants with severe thalassemias in Zhuhai City by genetic screening and prenatal diagnosis of thalassemia in the large population of 13 years.Our summary comes out of technical proposals for prenatal screening and diagnosis,which could be take example by preventative control of thalassemia in other regions of China where are prevalent.

Objective To treat hematospermia by ureteroscopy and investigate its application value for the treatment of hematospermia.Methods Nineteen patients with persistent hematospermia, TRUS,seminal vesicle MRI or CT were examined to exclude seminal vesicle tumor, tuberculosis, prostatic occupancy and preoperative prostatic fluid and drug sensitivity.Transurethral 4.5 - 6 F ureteroscopy entered through the microscopic seminal vesicle, wash of the old blood, reserved perfusion with Quinolones, and the lithoclasty on the seminal stones by holmium laser, resection of small polypi.Results The ureteroscopy was successful in 18 (95%) cases for bilateral seminal vesicle, wash and drug reserved perfusion, and one case was also successful seminal vesicle microscopy on the affected side; five cases with the seminal stones by olmium laser, three cases with small polypi by resection.The averse duration of the procedure was 35 10 -75) min.There were no compliocations during or after the operation.In 18 cases at 6 - 12 months follow-up the hematospermia and symptoms of hematospermia disappeared fully after 90 d.There was recurrence in one case which improved with anti-inflammaotry treatment.Conclusions Ureteroscopic treatment for persistent hematospermia by 4.5 - 6 F ureteroscopy through the seminal vesicle is effective and safe method and results in a micro-wound.

OBJECTIVE: To observe the short-term efficacy of autogenous bone pate and Palva graft for obliterating huge remnant mastoid cavity in canal wall down approach. METHOD: Retrospective analysis clinical data of twenty-one cholesteatomatous cases operated by one surgeon from 2004 to 2007. In twelve cases, simultaneous III type tympanoplasty (Sheehy, P. O. P) was performed. Other 9 cases had undergone mastoidectomy elsewhere before the admission. Six of them were still draining with huge remnant mastoid cavity, and the rest three patients had relapsed cholesteatomas with intermittent draining and huge mastoid cavity. Normal saline solution perfusion was used to measure the volume of remnant mastoid cavity. The criterion of huge remnant mastoid cavity is more than 8 ml. RESULT: Of twelve primary cases with III type tympanoplasty, 11 patients maintained a small, dry, and healthy mastoid cavity after twenty-seven days. The average increase of hearing level of them was 17.5dB, and the air-bone gap is less than 20 dB. Of one patient, bone pate was infected and was discharged. A dry mastoid cavity was achieved until fifty-five days after surgery. The patient is keeping a big air-bone gap caused by displacement of ossicle chain prosthesis. Just eighteen days later, other nine cases of revision mastoidectomy achieved a small, dry, and healthy mastoid cavity, with lightly improved hearing level. CONCLUSION Obliteration of a canal wall down huge mastoid cavity by Palva graft with autologous bone pate is a reliable and effective technique that results in a small, dry, low-maintenance mastoid cavity. The short-term efficacy of simultaneous III tympanoplasty is satisfactory if patient selection is suitable.
Adolescent ; Adult ; Cholesteatoma ; surgery ; Cholesteatoma, Middle Ear ; surgery ; Female ; Humans ; Male ; Mastoid ; surgery ; Middle Aged ; Retrospective Studies ; Surgical Flaps ; Transplantation, Autologous ; Treatment Outcome ; Tympanoplasty ; methods ; Young Adult

Repairing DNA double-strand breaks (DSBs) with homologous chromosomes as templates is the hallmark of meiosis. The critical outcome of meiotic homologous recombination is crossovers, which ensure faithful chromosome segregation and promote genetic diversity of progenies. Crossover patterns are tightly controlled and exhibit three characteristics: obligatory crossover, crossover interference, and crossover homeostasis. Aberrant crossover patterns are the leading cause of infertility, miscarriage, and congenital disease. Crossover recombination occurs in the context of meiotic chromosomes, and it is tightly integrated with and regulated by meiotic chromosome structure both locally and globally. Meiotic chromosomes are organized in a loop-axis architecture. Diverse evidence shows that chromosome axis length determines crossover frequency. Interestingly, short chromosomes show different crossover patterns compared to long chromosomes. A high frequency of human embryos are aneuploid, primarily derived from female meiosis errors. Dramatically increased aneuploidy in older women is the well-known "maternal age effect." However, a high frequency of aneuploidy also occurs in young women, derived from crossover maturation inefficiency in human females. In addition, frequency of human aneuploidy also shows other age-dependent alterations. Here, current advances in the understanding of these issues are reviewed, regulation of crossover patterns by meiotic chromosomes are discussed, and issues that remain to be investigated are suggested.
Cell Division/physiology* ; Chromosome Segregation/physiology* ; Humans ; Meiosis/genetics* ; Recombination, Genetic

Emerging and re-emerging RNA viruses occasionally cause epidemics and pandemics worldwide, such as the on-going outbreak of the novel coronavirus SARS-CoV-2. Herein, we identified two potent inhibitors of human DHODH, S312 and S416, with favorable drug-likeness and pharmacokinetic profiles, which all showed broad-spectrum antiviral effects against various RNA viruses, including influenza A virus, Zika virus, Ebola virus, and particularly against SARS-CoV-2. Notably, S416 is reported to be the most potent inhibitor so far with an EC of 17 nmol/L and an SI value of 10,505.88 in infected cells. Our results are the first to validate that DHODH is an attractive host target through high antiviral efficacy in vivo and low virus replication in DHODH knock-out cells. This work demonstrates that both S312/S416 and old drugs (Leflunomide/Teriflunomide) with dual actions of antiviral and immuno-regulation may have clinical potentials to cure SARS-CoV-2 or other RNA viruses circulating worldwide, no matter such viruses are mutated or not.
Animals ; Antiviral Agents ; pharmacology ; therapeutic use ; Betacoronavirus ; drug effects ; physiology ; Binding Sites ; drug effects ; Cell Line ; Coronavirus Infections ; drug therapy ; virology ; Crotonates ; pharmacology ; Cytokine Release Syndrome ; drug therapy ; Drug Evaluation, Preclinical ; Gene Knockout Techniques ; Humans ; Influenza A virus ; drug effects ; Leflunomide ; pharmacology ; Mice ; Mice, Inbred BALB C ; Orthomyxoviridae Infections ; drug therapy ; Oseltamivir ; therapeutic use ; Oxidoreductases ; antagonists & inhibitors ; metabolism ; Pandemics ; Pneumonia, Viral ; drug therapy ; virology ; Protein Binding ; drug effects ; Pyrimidines ; biosynthesis ; RNA Viruses ; drug effects ; physiology ; Structure-Activity Relationship ; Toluidines ; pharmacology ; Ubiquinone ; metabolism ; Virus Replication ; drug effects