Mussel-Mimetic Hydrogel Coating with Anticoagulant and Antiinflammatory Properties on a Poly(lactic acid) Vascular Stent.

Biodegradable stents are the most promising alternatives for the treatment of cardiovascular disease nowadays, and the strategy of preparing functional coatings on the surface is highly anticipated for addressing adverse effects such as in-stent restenosis and stent thrombosis. Yet, inadequate mechanical stability and biomultifunctionality limit their clinical application. In this study, we developed a multicross-linking hydrogel on the polylactic acid substrates by dip coating that boasts impressive antithrombotic ability, antibacterial capability, mechanical stability, and self-healing ability. Gelatin methacryloyl, carboxymethyl chitosan, and oxidized sodium alginate construct a double-cross-linking hydrogel through the dynamic Schiff base chemical and in situ blue initiation reaction. Inspired by the adhesion mechanism employed by mussels, a triple-cross-linked hydrogel is formed with the addition of tannic acid to increase the adhesion and antibiofouling properties. The strength and hydrophilicity of hydrogel coating are regulated by changing the composition ratio and cross-linking degree. It has been demonstrated in tests in vitro that the hydrogel coating significantly reduces the adhesion of proteins, MC3T3-E1 cells, platelets, and bacteria by 85% and minimizes the formation of blood clots. The hydrogel coating also exhibits excellent antimicrobial in vitro and antiinflammatory properties in vivo, indicating its potential value in vascular intervention and other biomedical fields.

Association of functional variant of aldehyde dehydrogenase 2 with acute myocardial infarction of Chinese patients.

BACKGROUND: The variant of ALDH2 was thought to be associated with Acute Myocardial Infarction (AMI) due to the consumption of alcohol. This study focused on how ALDH2 variant acts as an independent risk factor for AMI, regardless of alcohol consumption. METHODS AND RESULTS: We used the case-control INTERHEART-China study which took place at 25 centres in 17 cities in mainland China. Cases were patients with AMI and matched by age, sex, and site to controls. Information about alcohol consumption and genotype were collected. We divided cases and controls by alcohol consumption: alcohol intake group and no alcohol intake group. Then, calculated the Odd Ratio (OR) value with confidence interval (CI) at 95% level to find the association between ALDH2 variant and AMI. Results were then adjusted by sex, age, BMI, and other common risk factors of AMI. The study involves a total of 2660 controls and 2322 AMI patients. The no drink intake group showed that there was a correlation between the ALDH2 variant and AMI (OR = 1.236, 95% CI = 1.090-1.401, p = 0.00092). After adjustment of different risk factors this association remained (OR = 1.247, 95% CI = 1.099-1.415, p = 0.00062). Similar results were also obtained from the no alcohol intake group (OR = 1.196, 95% CI = 0.993-1.440, p = 0.05963), however, due to the limited sample size, the result was not significant enough statistically. CONCLUSION: From our results, ALDH2 variant is associated with the risk of AMI even in population that has no alcohol consumption. This suggests that ALDH2 variant may act as an independent risk factor for AMI.

Does Focal Kyphotic Deformity at Non-responsible Levels Affect the Outcomes of Anterior Cervical Decompression and Fusion?

OBJECTIVE: Focal cervical kyphotic deformity (FCK) without neurologic compression is not uncommon in patients with cervical spondylotic myelopathy (CSM) who underwent anterior cervical decompression and fusion (ACDF) surgery. It remains unclear whether FCK at non-responsible levels needs to be treated simultaneously. This study aims to investigate whether FCK at non-responsible levels is the prognostic factor for CSM and elucidate the surgical indication for FCK. METHODS: Patients with CSM who underwent ACDF between January 2016 and April 2021 were included. Patients were divided into two groups according to the presence of FCK and two classifications according to global cervical sagittal alignment. Clinical outcomes were compared using Japanese Orthopaedic Association (JOA) scores and recovery rate (RR) of neurologic function. Univariate and multivariate analysis based on RR assessed the relationship between various possible prognostic factors and clinical outcomes. The receiver operating characteristic curve (ROC) was used to determine the optimal cutoff value of the focal Cobb angle to predict poor clinical outcomes. RESULTS: A total of 94 patients were included, 41 with FCK and 53 without. Overall, the RR of neurologic function was significantly lower in the FCK than in the non-FCK group. Further analysis showed that the RR difference between the two groups was only observed in hypo-lordosis classification (kyphotic and sigmoid alignment), but not in the lordosis classification. Multivariate analysis showed that the preoperative focal Cobb angle in the FCK level (OR = 0.42; 95% CI = 0.18-0.97) was independently associated with clinical outcomes in the hypo-lordosis classification. The optimal cutoff point of the preoperative focal kyphotic Cobb angle was calculated at 4.05°. CONCLUSION: For CSM with hypo-lordosis, FCK was a risk factor for poor postoperative outcomes. Surgeons may consider treating the FCK simultaneously if the focal kyphotic Cobb angle of FCK is greater than 4.05° and is accompanied by cervical global kyphotic or sigmoid deformity.

TMEM135 maintains the equilibrium of osteogenesis and adipogenesis by regulating mitochondrial dynamics.

BACKGROUND: Disturbance in the differentiation process of bone marrow mesenchymal stem cells (BMSCs) leads to osteoporosis. Mitochondrial dynamics plays a pivotal role in the metabolism and differentiation of BMSCs. However, the mechanisms underlying mitochondrial dynamics and their impact on the differentiation equilibrium of BMSCs remain unclear. METHODS: We investigated the mitochondrial morphology and markers related to mitochondrial dynamics during BMSCs osteogenic and adipogenic differentiation. Bioinformatics was used to screen potential genes regulating BMSCs differentiation through mitochondrial dynamics. Subsequently, we evaluated the impact of Transmembrane protein 135 (TMEM135) deficiency on bone homeostasis by comparing Tmem135 knockout mice with their littermates. The mechanism of TMEM135 in mitochondrial dynamics and BMSCs differentiation was also investigated in vivo and in vitro. RESULTS: Distinct changes in mitochondrial morphology were observed between osteogenic and adipogenic differentiation of BMSCs, manifesting as fission in the late stage of osteogenesis and fusion in adipogenesis. Additionally, we revealed that TMEM135, a modulator of mitochondrial dynamics, played a functional role in regulating the equilibrium between adipogenesis and osteogenesis. The TMEM135 deficiency impaired mitochondrial fission and disrupted crucial mitochondrial energy metabolism during osteogenesis. Tmem135 knockout mice showed osteoporotic phenotype, characterized by reduced osteogenesis and increased adipogenesis. Mechanistically, TMEM135 maintained intracellular calcium ion homeostasis and facilitated the dephosphorylation of dynamic-related protein 1 at Serine 637 in BMSCs. CONCLUSIONS: Our findings underscore the significant role of TMEM135 as a modulator in orchestrating the differentiation trajectory of BMSCs and promoting a shift in mitochondrial dynamics toward fission. This ultimately contributes to the osteogenesis process. This work has provided promising biological targets for the treatment of osteoporosis.

The effect of ozone short-term exposure on flow-mediated dilation: Using data before and after COVID-19 lockdown in Shanghai.

BACKGROUND: Short-term ambient ozone exposure has been shown to have an adverse impact on endothelial function, contributing to major cardiovascular diseases and premature death. However, only limited studies have focused on the impact of short-term ozone exposure on Flow-mediated Dilation (FMD), and their results have been inconsistent. The current study aims to explore the relationship between short-term ambient ozone exposure and FMD. In addition, the study aims to investigate how lockdown measures for COVID-19 may influence ozone concentration in the atmosphere. METHODS: Participants were recruited from a hospital in Shanghai from December 2020 to August 2022. Individuals' ozone exposure was determined using residential addresses. A distributed lag nonlinear model was adopted to assess the exposure-response relationship between short-term ozone exposure and FMD. A comparison was made between ambient ozone concentration and FMD data collected before and after Shanghai's lockdown in 2022. RESULTS: When ozone concentration was between 150 and 200 µg/m3, there was a significant reduction in FMD with a 2-day lag. Elderly individuals (age ≥ 65), females, non-drinkers, and non-smokers were found to be more susceptible to high concentrations of ozone exposure. The lockdown did elevate ambient ozone concentration compared to the same period previously. INTERPRETATION: This study proposes that an ambient ozone concentration of 150-200 µg/m3 is harmful to endothelial function, and that a reduction in human activity during lockdown increased the concentration, which in turn reduced FMD. However, the underlying mechanism requires further research.

[Diagnosis and surgical treatment of giant intrathoracic solid tumors].

OBJECTIVE: To summarize the experience in diagnosis and surgical treatment of giant intrathoracic solid tumors. METHODS: The data of surgically treated 36 patients with giant intrathoracic solid tumors were analyzed, including 19 males and 17 females. Complete resection was achieved in 34 cases with superior vena cava angioplasty in 3 cases and ligation of the left anonymous vein in 2 cases. Six patients received postoperative radiotherapy. RESULTS: The symptoms in 32 cases were significantly improved. Two patients (5.6%) died of postoperative respiratory infection and failure. The mean postoperative hospital stay was 14.2 days. Pulmonary edema occurred in 6 cases due to rapid decompression of the lung. Pathological results showed that 25 cases had benign tumors and 11 had malignancy. During the follow-up of 1 to 22 years, all patients with benign tumors were still alive, but the patients with malignant tumors had a mean survival time of only 2.1 years. CONCLUSION: Surgical treatment for giant intrathoracic solid tumors is suggested whenever technically possible. Even though a tumor can not be completely resected, satisfied results could still be achieved if combined with postoperative radiotherapy. Proper anesthesia, satisfied exposure with a suitable incision, appropriate resection pattern and hemostatic method are the keys for successful surgical treatment.

[Protective effect of protein kinase C on heart function: an experiment with isolated rabbit hearts].

OBJECTIVE: To investigate the protective effect of protein kinase C on heart function. METHODS: The hearts of 40 rabbits were isolated, underwent Langendorff perfusion, and randomly divided into 4 equal groups: Group I (control group, the heart underwent long ischemia or preservation for I hour, was re-warmed and re-infused, and then re-perfused with K-H fluid), Group II (ischemic preconditioning group, perfusion was stopped for 5 minutes before the long ischemia, then the aorta was re-infused), Group III (specific activator of PKC, phorbol myristate acetate was infused inversely via the aorta before the perfusion of K-H fluid), and Group IV (polymyxin B, a specific antagonist of PKC, was infused after the infusion of PKC). Before the preservation and by the end of reperfusion left ventricle end systolic pressure (LVESP), and left ventricle end diastolic pressure (LVDSP) were measured. At the end of experiment specimens of myocardium were collected from each heart to measure the water content, the levels of lactic dehydrogenase and MB isoenzyme of creatine kinase (CK-MB), superoxide dismutase (SOD), and malonyldialdehyde (MDA). TUNEL method was used to measure the number of apoptotic cardiomyocyte. RESULTS: All heart resumed beating. The LVESP of Group II and III were both significantly higher than those of Groups I and IV (all P < 0.05) and the LVESP of Group III was significantly higher than that of Group II too (P < 0.05). The LVEDP of Group II and III were both significantly lower than those of Groups I and IV (all P < 0.05) and the LVEDP of Group III was significantly lower than that of Group II too (P < 0.05). The levels of CK-MB, LDH, and SOD of Group II and III were all significantly higher than those of Groups I and IV (all P < 0.05) and the levels of CK-MB and LDH of Group III was significantly higher than that of Group II too (P < 0.05). The level of MDA of Group II and III were both significantly lower than those of Groups I and IV (all P < 0.05) and the level of MDA of Group III was significantly lower than that of Group II too (P < 0.05). The water contents of Group II and III were both significantly lower than those of Groups I and IV (all P < 0.05). The numbers of TUNEL positive cell and apoptotic cells of Group II and III were all significantly lower than those of Groups I and IV (all P < 0.05). CONCLUSIONS: PKC can be activated by transient ischemia and PMA. PKC protects the heart function effectively.

Influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves in vitro.

OBJECTIVE: To assess the influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves. METHODS: US-made CarboMedics bileaflet valve, China-made Jiuling bileaflet valve and C-L tilting disc valve were tested via a pulsatile flow simulator in the aortic position. Testing conditions were set at mimic cardiac rates of 55 bpm, 75 bpm, 100 bpm with a constant mimic cardiac output of 4 L/min. The mean pressure differences (deltaP), leakage volumes (L(E)V) and closing volumes (C(L)V) across each valve, and effective orifice areas (EOA) were analyzed. RESULTS: Within physiological range, deltaP, L(E)V, and C(L)V decreased as mimic cardiac rate increased, with a large extent of variance. EOA increased along with an increase in mimic cardiac rate. It was a different response in terms of cardiac rate alteration for different types of mechanical prosthetic cardiac valves. CONCLUSION: Mimic cardiac rate change affects hydrodynamics of mechanical prosthetic cardiac valves. Within physiological range, the hydrodynamic of prosthetic bileaflet valve is better than that of tilting disc valve.

[Experimental study of differentiation of mouse bone marrow stromal stem cells into progenitor cardiomyocyte in vitro].

OBJECTIVE: To investigate the possibility of inducing mouse bone marrow stromal stem cells (MSCs) into progenitor cardiomyocytes in vitro. METHODS: The MSCs were isolated by adhesion culture in vitro and flow cytometery was employed to identify the phenotypes of the cell passages. 5-azacytidine was used to induce the stem cells to differentiate into cardiomyotes in the experimental group, which were then detected by RT-PCR, semi-quantitative RT-PCR, Western-blot analysis, electron microscopy and immunofluorescence technique. RESULTS: The isolated subcultured MSCs displayed a fusiform cell-like morphology. The MSCs were uniformly positive for CD29 and CD44 but negative for CD34 and CD45, and after induction, they expressed cardiomyocyte-specific transcription factors (NKx2-5/Csx and GATA4) and fetal ventricular cardiomyocyte-specific gene beta-myosin heavy chain, but not adult ventricular cardiomyocyte-specific gene alpha-myosin heavy chain as detected by RT-PCR. Western blotting identified the expressions of alpha-sarcomeric actin and desmin in the induced MSCs, with myofilament formation observed under electron microscope. Compared with the control group, the expression level of DNA methyltransferase mRNA was significantly lowered in the experimental group as observed by semi-quantitative RT-PCR (P<0.05). CONCLUSION: MSCs are capable of differentiating into progenitor cardiomyocytes.

Changes in phospholipase D activity of leukocytes during human systemic inflammatory response syndrome induced by cardiopulmonary bypass.

OBJECTIVE: To investigate the fluctuations in arterial leukocyte phospholipase D (PLD) activity during the perioperative period of open heart surgery under cardiopulmonary bypass (CPB), and the relationship between PLD activity and systemic inflammatory response induced by CPB. METHODS: Arterial blood was obtained from 26 patients undergoing open heart surgery at 8 different time points during the perioperative period, from which leukocytes were isolated for determination of PLD activity, CD11b expression and myeloperoxidase (MPO) activity. Plasma IL-6, IL-8 and C-reactive protein were also determined. The 26 cases were retrospectively divided into 3 groups according to perfusion time in order to detect the possible influences of CPB on PLD activity and IL-6 and IL-8 levels. RESULTS: When the ascending aorta was declamped, average arterial leukocyte PLD activity was 0.305 +/- 0.132 nmol choline.min(-1).mg(-1), 5.0 times higher of the pre-CPB value, and remained (5.4 times higher of the pre-CPB level) at 72 hours after CPB. Leukocyte CD11b expression and plasma IL-6 and IL-8 levels increased significantly at the end of CPB, while MPO activity and C-reactive protein concentration reached their peaks at 1 and 24 hours, respectively, after CPB. At the end of CPB, the arterial leukocyte PLD activity of patients whose CPB duration was longer than 90 minutes were 1.82- and 1.74-fold that of the other two groups with CPB lasting between 90 and 60 minutes and less than 60 minutes. CONCLUSIONS: Arterial leukocyte PLD activity rises significantly in CPB and its elevation is earlier and more persistent than other inflammation-related indicators tested; longer CPB duration leads to higher leukocyte PLD activity at the end of CPB. These results imply that PLD could be a new target for prevention of systemic inflammatory response induced by CPB.

Effects of phospholipase D on cardiopulmonary bypass-induced neutrophil priming.

OBJECTIVE: To investigate the relationship between phospholipase D (PLD) activation and neutrophil priming induced by cardiopulmonary bypass (CPB), and try to clarify whether CPB-induced systemic inflammatory response can be attenuated by inhibiting neutrophilic PLD activation. METHODS: Neutrophils were isolated from arterial blood of 8 patients undergoing valve replacement before operation and 30 min after initiation of CPB respectively. Both the preoperative and CPB-stirred neutrophils were subdivided into 5 groups by receiving different experimental interventions: (1) bacterial lipopolysaccharide (LPS, 10 ng x ml(-1)), (2) N-formylmethionylphenylalanine (fMLP, 1 micromol x L(-1)), (3) LPS+fMLP, (4) 1-butanol (0.5%)+LPS+fMLP, (5) vehicle. Elastase and myeloperoxidase (MPO) release was measured for the parameters of neutrophil activation, neutrophil PLD activity was determined by quantitation of choline produced from the stable product of phosphatidylcholine catalyzed by PLD. RESULTS: (1) Preoperative neutrophils treated with LPS+fMLP presented significantly higher PLD activity (13.48+/-2.61 nmol choline x h(-1) x mg(-1)) and released more elastase and MPO than cells treated with vehicle (PLD activity 3.70+/-0.49 nmol choline x h(-1) x mg(-1)), P<0.01), LPS (P<0.01) and fMLP respectively. In 1-butanol+LPS+fMLP group, PLD activity of preoperative neutrophils was lower than that in LPS+fMLP group (P<0.01), besides the release of elastase and MPO decreased sharply below both LPS+fMLP and fMLP groups (P<0.01). In LPS group, PLD activity was higher (P<0.01), while elastase and MPO release did not differ from control. fMLP group presented PLD activity, elastase and MPO release higher than control (P<0.01); nevertheless, lower than LPS+fMLP group (P<0.01). (2) CPB-stirred neutrophils presented prominent PLD activity increment, and even the control level was 3.59-fold of the pre-operative control (P<0.01). PLD activity in LPS+fMLP group was higher than that in other groups. Notably, PLD activity was even nonstatistically lower in 1-butanol+LPS+fMLP group than that in LPS or fMLP group. CPB-stirred neutrophils in LPS+fMLP group released more elastase and MPO than control, LPS, and 1-butanol+LPS+fMLP groups did (P<0.01); however, neither of the release was statistically different from that of fMLP group. CONCLUSIONS: Cardiopulmonary bypass enables neutrophil priming accompanied with significant increase in PLD activity. Inhibition of neutrophil PLD activation attenuates its priming and may alleviate CPB-induced systemic inflammatory reaction.

[Effect of recombinant human growth hormone on postoperative fatigue syndrome in patients after cardiac operations].

OBJECTIVE: To observe the effect of recombinant human growth hormone (rhGH) treatment on postoperative fatigue syndrome (POFS) in patients after cardiac surgery under cardiaopulmonary bypass (CPB). METHODS: 60 patients undergoing open heart surgery were randomly divided (double blind trial) into two groups : group A (injected with rhGH, 4.5 U Bid for 5-7 days) and group B (administrated with placebo). The patients were asked to score their sense of fatigue (Christensen scores). Their 24-hour urine was collected to calculate the daily nitrogen balance. The serum growth hormone (GH) and plasma proteins were detected. RESULTS: In the 4(th) day after operation, the level of fatigue was increased significantly in both groups, however, being lower in group A then in group B, and returned to the pre- operative level in the 8(th) postoperative day in group A (P < 0.01 ). The serum GH was similar in both groups before operation and was significantly increased on the first, fourth, and eighth days, especially the first day, postoperatively in group A (P < 0.01). The plasma total protein and albumin were similar in both groups before operation and on the first and fourth days postoperatively. On the 8(th) day postoperatively the plasma TP and albumin were significantly higher in group A than in group B (P < 0.05 and P < 0.01 respectively). The plasma retinol binding protein (RBP), prealbumin (PA), and transferrin (TFN) were similar in both groups before operation, on the first day after operation the plasma PA and TFN were lower than before operation in both groups. On the first postoperative day, the plasma RBP was higher in group A than in group B (P < 0.05), on the fourth day after operation the plasma PA and TEN were significantly higher in group A than in group B (P < 0.01). The time needed to wean from mechanical ventilation was 15.44 +/- 5.66 hr and 22.66 +/- 10.66 hr in groups A and B respectively (P < 0.01). In group A four patients established positive nitrogen balance on the second postoperative day and all patients in group B failed to obtain positiver nitrogen balance till the seventh postoperative day (P < 0.01). CONCLUSION: 1) Application of exogenous rhGH improves the symptoms of POFS, reduce the duration of POFS, and shorten the time needed to wean from mechanical ventilation, elevate plasma albumin, PA, TFN and RBP levels, and improve negative nitrogen balance. 2) The acute phase plasma proteins (such as PA, TFN, and RBP) are reliable biochemical indicators of POFS.

[Application of dynamic bubble trap in coronary artery bypass with cardiopulmonary bypass: an initial study].

OBJECTIVE: To investigate the effectiveness of dynamic bubble trap (DBT) on air microbubble elimination from both the cardiopulmonary bypass (CPB) circuit and middle cerebral arteries, and evaluate its possible impact on blood cells and coagulatory function. METHODS: Twenty patients undergoing coronary artery bypass graft (CABG), 12 males and 8 females, with similar perioperative data were assigned randomly to DBT group and control group. Each CABG was finished with identical circuit sets except the integration of a DBT between the arterial filtrator and the aortic cannula in the DBT group. Air microbubbles were detected before and after the integration of DBT with ultrasonographic detector and microembolism signals (MES) in middle cerebral arteries were counted by transcranial Doppler (TCD). Plasma free hemoglobin (PFH), lactate dehydrogenase (LDH), fibrinogen, platelet count, coagulation factor II and anti-thrombin III (ATIII) were also assayed respectively before the operation, at the termination of CPB, and 6 hours after the operation. RESULTS: In the DBT group the microbubbles of different size could be expelled significantly with the clearance rates between 68% - 74% (10 - 120 microm bubbles), 79% - 81% (20 - 120 microm bubbles), and 88% - 96% (40 - 120 microm bubbles). During the total CPB phase, the mean number of MES reached 197 +/- 137 in the control group and 158 +/- 178 in the DBT group, without a significant difference between these 2 groups. The PFH and LDH levels raised while the platelet count, fibrinogen level, and coagulation factor II and AT III activities decreased sharply after CPB in these 2 groups, however without significant differences in these parameters between the two groups. CONCLUSION: DBT integration into the CPB circuit enhances neither blood cell damage nor coagulation disturbance. DBT effectively eliminates air microbubbles in arterial conduit; however, its microembolus elimination function is prone to die down during the total period of CPB.

[Cox/maze III procedure combined with mitral valve replacement in treatment of rheumatic mitral valve disease with atrial fibrilation].

OBJECTIVE: To compare the curative effect of Cox/maze III procedure combined with mitral replacement and that of mitral valve replacement (MVR). METHODS: Fifty-six patients suffering from rheumatic heart disease with atrial fibrillation (AF) were treated by Cox/maze III procedure combined with MVR (maze group). Another 56 age, sex, and heart function-matched patients with the same diagnosis underwent MVR alone during the same period. Warfarin was administered after operation in both groups. Comparison of operative complication and curative effects was made. RESULTS: The aortic cross-clamp time and cardio pulmonary bypass time (CPB) were longer in maze group than in MVT group (75 +/- 22 min vs 41 +/- 11 min, P < 0.05 and 124 +/- 40 min VS 68 +/- 19 min, P < 0.05). Bleeding happened after the heart reatored beating in 2 patients in maze group and in one patient in MVT group, all these 3 patients responding satisfactorily to hemostasis. The early post-operative mortality was 1.79% (1/56) in both groups. In maze group, AF disappeared in all patients but one who had node rhythm. Normal sinus rhythm was restored in 98.18% of the patients (54/55). Atrial contractility was restored in all patients with sinus rhythm. One year after operation, 98.18% patients' cardiac function changed to grade and 1.82% changed to grade II. In MVR group AF disappeared after operation temporarily for 24 hours in 7 patients and re-appeared, and AF disappeared in one patients for 2 years so far. One year after operation, the cardiac function of 94.6% patients in MVR group changed to grade I, of 3.6% patients to grade II, and of 1.8% patients to grade III. No serious hemorrhage relate d to anticoagulant therapy happened. One patient in MVR group suffered from hemiplegia due to cerebral embolism. The late mortality was 1.8% on maze group amd 3.6% in MVR group. CONCLUSION: Cox/maze III procedure combined with NVR is safe and effective in treating rheumatic heart disease with AF.

[Dynamic change of apoptosis of alveolar cells in ischemia-reperfusion induced pulmonary injury: an experimental study with rats].

OBJECTIVE: To observe the dynamic changes of alveolar apoptosis in ischemia-reperfusion (IR) induced pulmonary injury, and to evaluate the roles of these two cell death styles, apoptosis and necrosis, in the progress of lung function deterioration in pulmonary IR injury. METHODS: Fifty-four Sprague-Dawley rats were made ischemia/reperfusion models by ischemia and reperfusion in situ in single lung. Thirty-six of the 54 rats in the experimental group were re-divided into 6 equal subgroups to undergo detection of partial pressure of oxygen (PaO2) of blood in left atrium, detection of lung tissue wet weight/dry weight ratio, histology of lung by light microscope, examination of ultrastructural changes of cells by transmission electron microscopy, and quantitative detection of apoptotic cells in the right middle lobe by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) 0 h, 0.5 h, 1 h, 2 h, 6 h, and 12 h respectively after the reperfusion (subgroups R0, R(0.5), R1, R2, R6, and R12). Another 18 rats in the experimental group were re-divided into 3 subgroups of 6 rats to undergo insertion of venous catheter into the main pulmonary artery via right ventricle to perfuse trypan blue so as to evaluate the cell death degree. The death index was observed under light microscope and the necrosis index was indirectly calculated by the equation: death index = apoptotic index + necrosis index. Thirty-six rats underwent sham operation. Twelve rats were used as preoperative blank controls. RESULTS: Proliferation of alveolar type II, but not alveolar type I cell, accompanied by ultrastructural morphological changes were seen 1 h, 2 h, and 6 h after reperfusion, the most prominently 2 h after reperfusion. Apoptotic index was elevated since 1 h after reperfusion, and peaked 2 h after reperfusion. Statistical analysis indicated that, compared with apoptotic index, the necrotic index was of more prominent correlation with blood oxygen partial pressure and wet/dry weight ratio. CONCLUSION: Alveolar apoptosis occurs in the early stage of reperfusion, and becomes the most prominent 2 h after reperfusion. Most apoptotic cells are alveolar type II cells. In the two styles of cell death in pulmonary IR injury, alveolar necrosis is more prominently correlated with progress of lung function deterioration.

[Assessing the significance of platelet count to in-vitro hemolytic test by roller pump].

This study was directed at estimating the value of platelet count in the course of in-vitro hemolytic tests by roller pump. Five paired in-vitro tests were conducted using the POLYSTAN pump(group A) and COBE pump(group B). The pumps ran 16 hours. The samples for platelet count and plasma-free hemoglobin were taken before pumping, and every 2 hours after 4 hours of pumping. The 2 groups' platelet count and plasma-free hemoglobin levels were found to be linearly increasing with the hours of pumping and linear regression analysis showed the platelet count and plasma-free hemoglobin were positively correlated. These data suggested that platelet count could be used as an index in evaluating the in-vitro hemolytic properties of blood pumps.

[Observation of the antithrombotic property of a new prosthetic heart valve in sheep].

UNLABELLED: To observe the antithrambotic property of a new prosthetic made double bileaflet valve of all-pyrolytic carbon. METHOD: Fifteen sheeps underwent mitral valve replacement (MVR) with this new mechanical valve. Each animal was placed on cardiopulmonary bypass. All of the sheep were given in an anticoagulation protocol and followed for three months. Final studies were performed on all animals surviving for more than 12 weeks. RESULT: Ten sheeps died within 48 h after operation, five sheeps survived. The long-term survivors were killed forautopsies, two sheeps were killed in the 1st week after operation, one in 12th weeks and two in 2.5 years. Pathological examination of 10 sheeps which died early after operation revealed that there was no either evidence of thromboembotic phenomenon, or any failures of the mechanical valve. Autopsy studies in the five long-term survivors revealed that the sewing ring was covered by a thin layer of microthrombi consisted most of platelets and fibrin in 1th week after operation. The sewing rings was covered by a tissue layer, with partial organized micro thrombi and endothelialization in 12th weeks after the operation. Two and half years after operation, the complete endothelialization presented around the sewing ring without restriction of bileaflet motion. The tissue ingrowth tends to stop at the pyrolytic carbon-fabric interface on both surfaces of left atrium and ventricle. This study demonstrated that the new prosthetic heart valve had not promoted thrombosis and thrombembolism.

[Assessing the transvalvular gradient of a Chinese-made jiuling solid pyrolytic carbon bileaflet heart valve prosthesis].

In order to assess the transvalvular gradient of a Chinese-made Jiuling solid pyrolytic carbon bileaflet heart valve prosthesis, we determined its hydrodynamics in the laboratory and then measured the hemodynamic performance in the animals and patiens. The Jiuling prosthesis was tested in a pulsatile flow simulator in the aortic position. Six sheep subjected to mitral replacement with 21 mm Jiuling prosthesis were measured by open cardiac catheterization intraoperatively. Doppler echocardiography and open cardiac catheterization under dobutamine stress were performed in two sheep 60 months after implantation. Clinically, 14 cases of aortic valve and 10 cases of mitral valve in the patients who underwent valve replacement with Jiuling heart valve prosthesis were measured by open cardiac catheterization and Doppler echocardiopgraphy. The results showed that Juiling heart valve prosthesis had lower mean transvalvular gradient (below 10 mmHg) at any given tissue annulus diameter. In animal experiments, the transvalvular gradients of 6 sheep were 5.2 +/- 1.7 mmHg intraoperatively, and of 2 sheep 60 months after implantation were 6.1 +/- 0.3 mmHg by catheterization. In patients, the mean transvalvular gradients in the aortic position measured by means of catheterization and echocardiography were 6.26-4.10 mmHg and 9.42-7.48 mmHg; the gradients in the mitral position were 2.10-1.9 mmHg and 5.281-4.10 mmHg respectively. The above results demonstrate that Jiuling valve prosthesis has excellent hemodynamic performance.