Biodegradable polymers as drug delivery systems have attracted investigators. They degrade in biological fluids to produce biocompatible and nontoxic products, which could be removed from the body by normal physiological pathways without extra surgical removal. In this article, literatures on biodegradable polymers mainly served as matrix in controlled release systems are analyzed and reviewed.

Objective To investigate the perinatal outcomes of pregnancies complicated with varying degrees of thrombocytopenia.Methods Clinical data of 305 pregnant women with thrombocytopenia,who admitted to Peking University People's Hospital from January 1,2000 to January 31,2010 were retrospectively analyzed.The etiological diagnosis of them were gestational thrombocytopenia (GT),idiopathic thrombocytopenic purpura (ITP) or undetermined.The patients were divided into 4 groups according to the minimal level of platelets in pregnancy ( platelets count was lower than 100 ×109/L at least twice) : groupⅠ,(50-100) ×109/L (n=101) ; group Ⅱ,(30-50) × 109/L (n = 85); group Ⅲ,(10-30) × 109/L (n = 87); group Ⅳ,< 10 × 109/L (n = 32).Demographic data such as pregnancy complications,treatment,neonates and follow-up results of the patients in each group were compared with ANOVA,Spearman rank correlation analysis,Chirsquare test and Chi-square trend test in SPSS 17.0.Results Medical complications in pregnancy of these patients included hypertensive disorder complicating (n = 35,11.48%) and abnormal glucose metabolism (n=23,7.54%),no difference was found in the incidence of these diseases among the four groups.There were 68 patients complicated with anemia (22.30%),40 preterm delivery (13.11%),60 postpartum hemorrhage (19.67%); there were significant differences in the incidence among the four groups (P＜0.05),the incidence increased with the aggravation of thrombocytopenia (P＜0.05).There were 2 cases of puerperal infection (0.66%),no maternal deaths.Fifty-one patients (16.72%) accepted treatment of corticosteroids or Gamma globulin during pregnancy.There were 116 cases (38.03%) of vaginal delivery and 189 cases (61.97%) of cesarean section.The postpartum bleeding amount within 24 hours increased with the aggravation of thrombocytopenia.Two hundred and eleven (69.18%) patients were followed up and platelet count regained normal,among which 152 cases recovered within six months after delivery.The recovery rates were 90.59% (77/85),82.36% (42/51),46.16% (24/52) and 39.13% (9/23) from group Ⅰ to group Ⅳ,as declined with the aggravation of thrombocytopenia in pregnancy ( x2trend = 42.616,Ptrend =0.000).Among the 306 perinatal fetuses,neonatal outcomes included 301 live births,5 fetal deaths,4 early neonatal deaths,4 low birth-weight infants after term birth,1 intracranial hemorrhage and 18 (5.98%) neonatal thrombocytopenia cases.Incidence of neonatal thrombocytopenia increased with the aggravation of maternal thrombocytopenia.Sixteen cases of neonatal thrombocytopenia recovered at 3-8 weeks after birth,but two cases did not recover within three years during followed up.Conclusions The perinatal outcomes are different in pregnancies complicated with varying degrees of thrombocytopenia.As thrombocytopenia in pregnancy become worse,the risk of anemia,premature delivery,postpartum hemorrhage and neonatal thrombocytopenia increases.While,perinatal outcomes may be better under close perinatal care.

Objective To investigate the etiology and clinical characteristics of pregnancy-emerged thrombocytopenia.Methods A retrospective analysis was conducted on clinical data of 159 pregnancies with thrombocytopenia,who were admitted to Peking University People's Hospital from January 2000 to January 2010.All the patients recruited in this study had no history of blood or immune system disease before pregnancy,and thrombocytopenia was the predominate clinical manifestation during pregnancy,with platelet counts less than 100 × 109/L at least twice during pregnancy.The thrombocytopenia should not be induced by drugs,viral infections,preeclampsia or hemolysis,elevated liver enzymes,and low platelets syndrome (HELLP).All cases were followed up.The general condition,the onset time of thrombocytopenia,platelet changes,accompany symptoms,maternal and perinatal outcomes as well as follow-up conditions were compared based on the etiology.Results ( 1 ) Etiology:among the 159 cases,101 (63.5％) were diagnosed gestational thrombocytopenia (GT) ;43 ( 27.0％ ) were idiopathic thrombocytopenic purpura(ITP) ;9 ( 5.7％ ) were blood system diseases,including 4 cases of megaloblastic anemia( MA ),2 cases of aplastic anaemia (AA),and 3 cases of myelodysplastic syndrome(MDS).Six cases (3.8％)were diagnosed immune system diseases,including 3 cases of systemic lupus erythematosus ( SLE),2 cases of antiphospholipid syndrome (APS),and 1 case of Evans syndrome.(2)Maternal and perinatal outcomes:pregnancy induced hypertension was diagnosed in 21 cases ( 13.2％ ),abnormal glucose metabolism in 13 cases ( 8.2％ ),anemia in 44 cases ( 27.7％ ) and preterm delivery in 18 cases ( 11.3％ ).Twenty-nine cases ( 18.2％ ) were treated with corticosteroids or gamma globulin during pregnancy.The average gestational week was 38 weeks.Fifty-five cases ( 34.6％ ) underwent vaginal delivery,104 cases ( 65.4％ ) received cesarean section.Postpartum hemorrhage was observed in 34 cases (21.4％),and puerperal infection happened in 2 eases ( 1.3％ ).No maternal death was found.In a total of 160 fetuses (including twins),there were 157 live births.Three cases of fetal death and 2 cases of early neonatal deaths were observed.Fetal growth restriction was observed in 4 cases,and neonatal thrombocytopenia was seen in 6 cases.No intracranial hemorrhage was detected.(3)The onset time of thrombocytopenia:among the 159 cases,29 cases ( 18.2％ ),67 cases (42.1％ ),63 cases (43.6％) of thrombocytopenia were detected in the first,second and third trimester,respectively.There was a significant difference of the onset time of thrombocytopenia between GT and ITP groups( P ＜ 0.05 ).Patients with GT tended to have a later onset of thrombocytopenia,which mainly happened in the second and third trimester,while patients with ITP tended to happen in the first and second trimester.(4)The degree of thrombocytopenia:the cases with the minimum platelets level of (51 - 100) × 109/L,(31 - 50) × 109/L,( 10 - 30) × 109/L,＜ 10 × 109/L during pregnancy were 75 (47.2％ ),39 (24.5％ ),31 ( 19.5％ ),14( 8.8％ ) respectively.There was a significant difference between GT and ITP groups in the lowest platelets level (P ＜ 0.01 ).(5)Thrombocytopenia accompany with anemia:among the 159 cases,there were 44 cases (27.7％ ) accompanied with anemia.The proportion was 9.9％ ( 10/101 ) in GT group,58.1％ (25/43) in ITP group,with significant difference(P ＜0.01 ).Anemia was also found in 5 cases in blood system disease group (5/9),and 1 case in immune system disease group (Evans syndrome,1/6).Pancytopenia was observed in 2 cases with ITP (4.7％,2/43 ) and 3 cases with blood system disease ( AA:1 cases,MA:2 cases,3/9).(6) The recovery of the platelets counts postpartum:the postpartum follow-up periods were 7 months to 10 years.Patients recovered within 1 week,6 weeks,6 months postpartum were 66 cases ( 41.5％ ),43 cases ( 27.0％ ),17 cases ( 10.7％ ) respectively.The platelets counts did not recover within 6 months postpartum in 33 cases(45.7％ ).Conclusions GT is the leading cause of pregnancy-emerged thrombocytopenia followed by ITP.There are significant differences between GT and ITP in the onset time of thrombocytopenia,the lowest platelets level,the proportion of anemia accompanied and the postpartum recovery.Other etiologies including immune and blood system diseases are rare.The relevant examinations should be taken for etiology and differential diagnosis.

OBJECTIVE To investigate the trend of distribution and drug resistance of clinical isolates of Enterobacter cloacae during the last three years in our hospital. METHODS Strains collected from daily specimens were identified and drug resistantce with SENSITITRE bacteria analysis system. RESULTS The most strains were isolated from samples of sputum,urine,nad other excretion. The drug resistance rates to imipenem and cefepime were less than 32%. Cefoxitin,ampicillin and cefazolin were ineffective to contralE. cloacae. The drug resistance rates to penicillins,cephalosporins,chloramphenicol and aminoglycoside antibiotics increased more than 20% in last three years. CONCLUSIONS E. cloacae is multiple-resistant to antibiotics and displays higher levels of antibiotic resistance. It is suggested that antibiotics be used reasonably under the guidance of antibiotic susceptibility testing.

Objectives To summarize the maternal and fetal outcomes of patients with essential thrombocythemia (ET), and tentatively propose possible solutions for different clinical scenarios.Methods We retrospectively studied the clinical data, treatment, outcomes and follow-up status in 18 consecutive cases of young women with ET visited Peking University People's Hospital, among whom 22 pregnancies occurred from March 2005 to January 2015.Rank-sum test, Chi-square test or Fisher exact test were applied for statistics.Results (1) Out of the total 22 pregnancies, 17 (77％) were successful (term live births) and five (23％) ended in miscarriages, among which four were spontaneous abortion in first trimester.(2) Six pregnancies did not received any therapy, while 16 received various treatments before and/or during pregnancy, including oral Aspirin(single/joint), Hydroxyurea, Interferon-α (IFN-α) and platelet apheresis.(3) Treatments before/during pregnancy improved the live birth rate significantly (15/16 vs 2/6, P=0.009).Platelet (PLT) count of the newborns were all normal till the time at follow-up.(4) The median PLT count in those patients before Aspirin therapy was 761 × 109/L[(448-1 213) × 109/L, and 639× 109/L[(283-1 908) × 109/L] thereafter, which showed no significant difference (Z=-0.405, P=0.686).(5) The PLT counts in those patients before combination therapy of Aspirin and IFN-α was 989 × 109/L[(435-1 504) × 109/L], and 498 × 109/L[(186-559) × 109/L] thereafter, which decreased significantly (Z=-2.366, P=0.018).Conclusions (1) First-trimester spontaneous abortion is the most common complication of ET in pregnancy.(2) A specific treatment strategy may improve the pregnant outcomes without long-term harmful effect up to now.(3) IFN-α and/or Aspirin might be the first-line therapy in women with ET during pregnancy.

Objective There is still controversy over the effect of hyperglycemia on the tolerance of heart to ischemia/reperfusion(I/R)injury in patients with diabetes mellitus. The aim of this study was to evaluate the effect of hyperglycemia on I/R-induced ventricular arrythmia in isolated diabetic rat hearts. Methods Twenty-four healthy male SD rats weighing 210-250g were randomly divided into two groups: control group(C, n=10) and diabetes mellitus group(DM, n=14). Diabetes mellitus was induced by intraperitoneal injection of streptozotocin 60 mg?kg~(-1). Blood glucose was measured 72h later and every week thereafter. Diabetes mellitus was defined as persistent hyperglycemia(blood glucose≥16.7 mmol/L after meal). The diabeticrats received no insulin. The rats were anesthetized with pentobarbital 60mg?kg~(-1). The hearts were immediately removed and perfused with oxygenated(95% O_2, 5% CO_2)Krebs-Henseleit buffer(KHB)in a Langendorff apparatus at a constant perfusion pressure of 80 mm Hg. The 14 diabetic rats were further divided randomly into 2 subgroups: (1)DM+KHB (n=7) and (2) DM+GLU(n=7) in which glucose 3.6 g was added to KHB 1000ml. After 20 min equilibration all hearts were subjected to 30 min global ischemia followed by 40 min reperfusion. Epicardial electrocardiogram was monitored. The incidence of ventricular tachycardia(VT) and ventricular fibrillation(VF) and their duration were measured. The severity of arrhythmia was quantified by arrythmia score(AS). Coronary outflow was collected for determination of creatine kinase(CK) release. Results The incidence of ischemia-induced arrythmia was significantly lowered in diabetic hearts. The incidence of VT was 14.3% and VF 28.6% in DM+KHB subgroup as compared to 60%(VT) and 100%(VF) in the control group. The CK release was significantly lower in diabetes group(DM) than in control group(C); furthermore the CK release in DM=KHB subgroup was lower than that in DM=GLU subgroup. Conclusion Diabetic rat hearts are less susceptible to I/R induced arrythmia. Hyperglycemic perfusion reduces to some extent the increased tolerance to I/R injury in diabetic rat hearts as shown by increased CK release in DM+GLU subgroup but hyperglycemic perfusion has anti-arrhythmic action as shown by 0% incidence of VT and VF in DM+GLU subgroup.

ObjectiveTo investigate the changes in stroke volume variation (SVV) monitored by FloTrac/Vigileo system during mechanical ventilation in patients undergoing pulmonary lobectomy.MethodsForty-four ASA Ⅰ or Ⅱ patients aged 44-64 yr weighing 47-86 kg undergoing elective pulmonary lobectomy performed under general anesthesia were studied.Blood volume was maintained by fluid (crystalloid∶ colloid 1∶1) infusion at a rate of 6-8 ml·kg-1 ·h-1.Cardiac output index (CI),stroke volume index (SVI) and SVV were measured based on arterial pressure wave form analysis by FloTrac/Vigileo System (Edwards Co.,USA) and recorded at following time points:at 5 min of two-lung ventilation (TLV) in supine position,2 min TLV in lateral position,during one-lung ventilation (OLV) before thoracotomy,at 5 and 30 min of OLV after thoracotomy,1 and 15 min OLV + PEEP of 5cm H2 O,before and immediately and 1 min after reflation of the remaining lobes.The normal value for SVV is less than 13％.ResultsThe hemodynamic parameters were stable during lobectomy.CI and SVI were within normal range.SVV was less than 13％ at all time points except that at immediately after reflation of the remaining lobes.ConclusionSVV obtained with FloTrac/Vigileo system can be used to guide fluid therapy during OLV in mechanically ventilated patients undergoing pulmonary lobectomy.

Objective To explore the effects of two lubricants on skin preparation from donor site in patients with skin flap transplantation. Methods According to digit number table, 83 patients undergoing wound repair using modified fascia flap were divided into observation group (n=41) and control group (n=42). The former group were treated with Johnson K-Y Lubricant, while the latter with talcum powder. The two groups were compared in terms of the skin flap quality from donor site, pain degree and number of bacteria before and after transplantation. Results There was no significant difference in bacteria number before and after transplantation in the two groups (P>0.05), but the difference between the groups was significant (P<0.01). The flap preparation quality in the observation group was significantly better than that of control group and the pain degree was significantly lower than that of observation group. Conclusion Johnson K-Y Lubricant can significantly improve flap preparation quality and reduce pain.

Objective To investigate the effect of alpha-lipoic acid on oxidative stress and cerebral edema after hypoxic-ischemic brain damage (HIBD)in neonatal rats.Methods A total of 108 neonatal 7-day-old Wistar rats were randomly divided into 3 groups:sham-operated group(sham, n=36), HIBD group(HIBD, n=36) and alpha-lipoic acid-treated group (treated group, n=36).Each group was divided into 3 sub-groups (n=12, per sub-group) based on different time points after HIBD (1 d, 3 d, 7 d).HIBD rat models were established by ligating the left common carotid artery, The sham-operated group and the HIBD group were treated with normal sodium injection intraperitoneally; treated group were treated with alpha-lipoic acid 100 mg/kg every 12 hours in 5 days.Animals were sacrificed at different time points.Changes of brain water content were determined by dry-wet weight method.And the levels of SOD,MDA,GSH-PX were measured.Results HIBD group showed an upward trend in brain water content and the level of MDA after HIBD, were higher than that of sham-operated group at each time point (P<0.05).Meanwhile, the levels of SOD and GSH-PX showed the downward trend in HIBD group.The levels of brain water content and the level of MDA in treated group were significantly lower than HIBD group at each time point ( P<0.05 ) .And the levels of SOD and GSH-PX in treated group were significantly higher than HIBD group at 3 d and 7 d.on the contrary , the level of MDA in treated group was significantly lower than HIBD group at 3 d and 7 d.Conclusion Alpha-lipoic acid can amiliorate cerebral edema, so it can prevent HIBD.The neuronal protective mechanism might be reverse oxidative imbalance in the brain of neonatal rats with HIBD.

Objective To evaluate the effects of exogenous hydrogen sulfide (H2S) on nitric oxide (NO) and nitric oxide synthase (NOS) during lung ischemia-reperfusion in a rat model of lung transplantation.Methods Forty pathogen-free male Sprague-Dawley rats,weighing 250-350 g,aged 2-3 months,were used as donor and recipient rats in this study.The animals were randomly divided into 4 groups (n =10 each):sham operation group (group S); lung transplantation group (group L); lung transplantation + H2S synthesis-CSE inhibitor D,L-propargylgylcine (PPG) group (group PPG); lung transplantation + exogenous H2S donor NaHS group (group NaHS).The donor lungs were removed from live donor rats and placed in low potassium dextran solution at 4 ℃.Orthotopic left lung transplantation was performed using modified three-cuff technique and the time for cold ischemia was 50-70 min.In PPG and NaHS groups,PPG 37.5 mg/kg and NaHS 14 μmol/kg were injected intraperitoneally at 5 min before opening of the hilum of the transplanted lung.The implanted donor lungs were ventilated and reperfused.The donor lungs were removed after being implanted,ventilated and reperfused for 2 h for microscopic examination and for determination of wet to dry lung weight (W/D) ratio and the levels of malondialdehyde (MDA),myeloperoxidase (MPO),inducible NOS (iNOS),endothelial NOS (eNOS),and NO.Results Compared with group S,W/D ratio and the levels of MDA,iNOS,NO and MPO were significantly increased,and the content of eNOS was decreased in group L,and no significant change was found in the parameters mentioned above in group NaHS.Compared with group L,W/D ratio and the levels of MDA,iNOS,NO and MPO were significantly increased,and the content of eNOS was decreased in group PPG,and W/D ratio and the levels of MDA,iNOS,NO and MPO were decreased,and the content of eNOS was increased in group NaHS.The pathological changes of lungs were significantly attenuated in group NaHS as compared with group L.Conclusion Exogenous H2S can attenuate the lung ischemia-reperfusion injury in a rat model of lung transplantation,and decreased iNOS activity and increased eNOS activity are involved in the mechanism.