解木糖赖氨酸芽孢杆菌发酵和生物催化产生L-2-氨基己二酸

以解木糖赖氨酸芽孢杆菌XX-2为出发菌株,110 mmol/L L-赖氨酸单盐酸盐为发酵前体,144 h发酵后L-2-氨基己二酸浓度达到10.4 mmol/L,产率为9.5%.以解木糖赖氨酸芽孢杆菌XX-2全细胞为生物催化剂,利用共生的L-赖氨酸6-脱氢酶和?-1-哌啶啉-6-羧酸脱氢酶催化L-赖氨酸单盐酸盐转化为L-2-氨基己二酸.最优条件为:细胞浓度为45 g(干重)/L,L-赖氨酸单盐酸盐浓度为100 mmol/L,pH=7.0,温度为30℃,反应时间144 h.在最优条件下,从100 mmol/L L-赖氨酸单盐酸盐产生90 mmol/L L-2-氨基己二酸,产率为90%.我们推测了生物催化过程中L-2-氨基己二酸产生的反应机理.

早产儿真菌性败血症临床分析(附16例报告)

目的探讨早产儿真菌性败血症的临床特点,以提高该疾病的诊治水平。方法选择2013年1月—2014年9月湖北省妇幼保健院新生儿重症监护病房收治的早产儿真菌性败血症病例16例,对患者的一般状况、发病时间、首发症状、血小板、CRP、1,3-β-D葡聚糖、血培养结果感染指标进行回顾性分析,比较治疗前与治疗中、治疗后的血小板、C反应蛋白及1,3-β-D葡聚糖的变化情况。结果新生儿真菌性败血症的病原菌以热带假丝酵母菌为主,发病日龄为生后5～36 d,平均(14±5.5) d;喂养不耐受、频繁呼吸暂停、反应差、发热是新生儿真菌性败血症的常见首发症状;多数患儿出现血小板减少,C反应蛋白、1,3-β-D葡聚糖增高,抗真菌治疗7 d后多数患者血小板可恢复正常,治疗2～3周后C反应蛋白、1,3-β-D葡聚糖可恢复正常,应用氟康唑、卡泊芬净治疗新生儿假丝酵母菌性败血症可取得满意疗效。结论早产儿真菌性败血症的临床表现缺乏特异性,对有高危因素的早产儿血小板减少、1,3-β-D葡聚糖增高可考虑早期真菌感染,氟康唑仍为首要治疗新生儿真菌性败血症一线药物,早期发现及时治疗是治疗成功的关键。

类产碱假单胞菌XW-40发酵-生物转化级联产生D-脯氨酸

建立了一个新颖的用于产生D-脯氨酸的发酵-生物转化过程.发酵过程中,以DL-脯氨酸为发酵前体,类产碱假单胞菌XW-40利用L-对映体诱导产生脯氨酸脱氢酶,D-对映体完全保留.在最优条件下,发酵阶段产生6 g/L D-脯氨酸.生物转化过程中,细胞不经分离,发酵液直接作为反应介质.采用分批补料策略实现DL-脯氨酸中L-对映体的转化.DL-脯氨酸单批补料浓度为10 g/L,补料次数达到5批.通过发酵和生物转化的级联,累积的D-脯氨酸浓度达到31 g/L,ee>99%.推测了生物转化过程中D-脯氨酸产生的反应机理.

Effects of inhaled nitric oxide in neonatal hypoxemic respiratory failure from a multicenter controlled trial

Background Hypoxemic respiratory failure （HRF） is one of the most common causes for neonatal infants requiring aggressive respiratory support. Inhaled nitric oxide （iNO） has been established routinely as an adjunct to conventional respiratory support in developed countries. The aim of this study was to investigate effects of iNO in neonates with HRF in resource limited condition with no or limited use of surfactant, high frequency oscillatory ventilation （HFOV） and extracorporeal membrane oxygenation.Methods A non-randomized, open, controlled study of efficacy of iNO was conducted over 18 months. Eligible term and near-term neonates from 28 hospitals with HRF （oxygenation index ＞15） were enrolled prospectively into two groups as either iNO or control. Oxygenation improvement and mortality as primary endpoint were determined in relation with dosing and timing of iNO, severity of underlying diseases, complications and burden. Intention-to-treat principle was adopted for outcome assessment. Response to iNO at 10 or 20 parts per million （ppm） was determined by oxygenation in reference to the control （between-group） and the baseline （within-group）.Results Compared to 93 controls, initial dose of iNO at 10 ppm in 107 treated infants significantly improved oxygenation from first hour （P=0.046）, with more partial- and non-responders improved oxygenation with subsequent 20ppm NO （P=0.018）. This effect persisted on days 1 and 3, and resulted in relatively lower mortalities （11.2% vs. 15%）whereas fewer were treated with surfactant （10% vs. 27%）,HFOV （＜5%） or postnatal corticosteroids （＜10%） in both groups. The overall outcomes at 28 days of postnatal life in the iNO-treated was not related to perinatal asphyxia,underlying diseases, severity of hypoxemia, or complications,but to the early use of iNO. The cost of hospital stay was not significantly different in both groups.Conclusions With relatively limited use of surfactant and/or HFOV in neonatal HRF, significantly more responders were found in the iNO-treated patients as reflected by improved oxygenation in the first three days over the baseline level. It warrants a randomized, controlled trial for assessment of appropriate timing and long-term outcome of iNO.

Current status of neonatal acute respiratory disorders： a one-year prospective survey from a Chinese neonatal network

Background We conducted a prospective, multicenter investigation of incidence, management and outcome of neonatal acute respiratory disorders （NARD）, and evaluated related perinatal risk factors and efficacy of respiratory therapies in neonatal intensive care units （NICUs） in a Chinese neonatal network.Methods Data were prospectively collected in 2004-2005 from infants with NARD defined as presence of respiratory distress and oxygen requirement during the first 3 days of life.Results A total of 2677 NARD was classified （20.5% of NICU admissions）. There were 711 （5.44%） with respiratory distress syndrome （RDS）, 589 （4.51%） pulmonary infection, 409 （3.13%） meconium aspiration syndrome, 658 （5.03%）aspiration of amniotic fluid and 239 （1.83%） transient tachypnoea. Meconium aspiration syndrome had the highest rate with fetal distress, transient tachypnoea from cesarean section, and RDS with maternal disorders. Assisted mechanical ventilation was applied in 53.4% of NARD, and in above five disorders with 84.7%, 52.3%, 39.8%, 24.5%, and 53.6%,respectively. Corresponding mortality in these disorders was 31.4%, 13.6%, 17.8%, 4.1% and 5.0%, respectively.Surfactant was provided to 33.9% of RDS. In all RDS infants, the survival rate was 78.8% if receiving surfactant, and 63.4% if not （P 〈0.001）.Conclusions This study provided NICU admission-based incidence and mortality of NARD, reflecting efficiency of advanced respiratory therapies, which should be a reference for current development of respiratory support in NICU at provincial and sub-provincial levels, justifying efforts in upgrading standard of care in emerging regions through a collaborative manner.