[Spectral studies on the mechanism of rare earth poly (vinyl chloride) thermal stabilizers]

Rare earth Poly (Vinyl Chloride) (PVC) thermal stabilizers are one kind of effective and non-toxic stabilizers developed recently. By photoacoustic (PA) spectra and FT-IR analysis, their excellent performance in PVC stabilization progress can be studied conveniently. Good color remaining ability of rare earth stabilizers can be shown clearly by PA spectra and compared with others easily. From the IR spectrum and process data, the extra stabilization ability of rare earth stabilizers may be attributed to their conformation transforming effect.

Heparin-coated circuits reduce myocardial injury in heart or heart-lung transplantation: a prospective, randomized study

BACKGROUND

The effects of heparin-coated (HC) circuits have been primarily investigated in routine cardiac operations with limited duration of cardiopulmonary bypass (CPB) and ischemia. Their benefits have not been conclusively proven but could be more significant when CPB and ischemic times are longer, such as during heart transplantation (HTx) or heart-lung transplantation (HLTx).

METHODS

In a 22-month period, 29 patients undergoing HTx and HLTx were randomly divided into two groups using HC (Duraflo II, n = 14, 10 HTx and 4 HLTx) or uncoated but identical circuits (NHC group, n = 15, 10 HTx and 5 HLTx). All patients received full systemic heparinization (3 mg/kg) during CPB. Plasma endotoxin, interleukin (IL)-6, IL-8, IL-10, IL-12, and cardiac troponin-I were measured before heparin administration, immediately after aortic cross-clamping, 5, 30, 60, 90, 120 minutes, and 12 and 24 hours after aortic declamping. The intensive care unit (ICU) staff and the laboratory technologists were blinded as to the use of HC circuits.

RESULTS

No statistically significant differences between groups were found with respect to all baseline values, duration of CPB and aortic cross-clamping, graft ischemic time, doses of heparin, postoperative blood loss and transfusion, peak lactate and creatine kinase-MB isoenzyme values, duration of mechanical ventilation, or length of ICU stay. One patient in each group died during the hospital stay. Patients in the HC group needed more protamine sulfate after CPB. Although endotoxin levels were similar in the two groups, significantly lower IL-6, IL-8, and IL-10 levels were observed 1 hour after aortic declamping in the HC group. The release of cardiac troponin-I was also significantly reduced in the HC group 12 and 24 hours after reperfusion.

CONCLUSIONS

The use of HC circuit limits both pro- and anti-inflammatory responses to CPB. It may also reduce myocardial injury after prolonged duration of CPB and ischemia.

Cytokines in myocardial injury: impact on cardiac surgical approach

Myocardial ischemia-reperfusion injury associated with cardiac surgery is an acute inflammatory process in which activated leukocytes and endothelial cells play a critical role. Recent data indicate that the release of cytokines is crucial in inducing leukocytes and endothelial cells activation during cardiopulmonary bypass (CPB). Some inflammatory cytokines can be produced locally from the heart, particularly interleukin (IL)-8, which may further enhance leukocyte activation and accumulation in the injured myocardium. In fact, postoperative levels of cardiac troponin-I, a highly specific marker of myocardial injury, correlated strongly with IL-8 values in patients undergoing coronary artery bypass grafting (CABG). Off-pump CABG is associated with less IL-8 production compared with conventional procedure, which may in turn reduce the degree of myocardial injury. On the other hand, reduced release of IL-8 and cardiac troponin-I has also been discovered following the use of heparin-coated CPB circuits. In addition, the balance between pro- and anti-inflammatory mediators may be even more crucial in determining the extent of injury. Hence, avoiding the use of CPB or improving the biocompatibility of CPB may lead to better myocardial preservation. Research along these lines is expected to help in the development of ideal therapeutic strategies to minimize the inflammatory response and subsequent myocardial injury associated with cardiac surgery.

The topoisomerase I poison camptothecin generates a Chk1-dependent DNA damage checkpoint signal in fission yeast

The protein kinase Chk1 is essential for the DNA damage checkpoint. Cells lacking Chk1 are hypersensitive to DNA-damaging agents such as UV light and gamma-irradiation because they fail to arrest the cell cycle when DNA damage is generated. Phosphorylation of Chk1 occurs after DNA damage and is dependent on the integrity of the DNA damage checkpoint pathway. We have tested whether a topoisomerase I inhibitor, camptothecin (CPT), generates DNA damage in the fission yeast Schizosaccharomyces pombe that results in Chk1 phosphorylation. We demonstrate that Chk1 is phosphorylated in response to CPT treatment in a time- and dose-dependent manner and that phosphorylation is dependent on an intact DNA damage checkpoint pathway. Furthermore, we show that cells must be actively dividing in order for CPT to generate a Chk1-responsive DNA damage signal. This observation is consistent with a model whereby the cytotoxic event caused by CPT treatment is the production of a DNA double-strand break resulting from the collision of a DNA replication fork with a trapped CPT-topoisomerase I cleavable complex. Cells lacking Chk1 are hypersensitive to CPT treatment, suggesting that the DNA damage checkpoint pathway can be an important determinant for CPT sensitivity or resistance. Finally, as a well-characterized, soluble agent that specifically causes DNA damage, CPT will allow a biochemical analysis of the checkpoint pathway that responds to DNA damage.

Avoiding cardiopulmonary bypass in multivessel CABG reduces cytokine response and myocardial injury

BACKGROUND

Proinflammatory cytokines play a key role in the inflammatory cascade after cardiopulmonary bypass and may induce cardiac dysfunction. We compared the production of cytokines and the degree of postoperative myocardial injury in patients with multivessel coronary artery disease undergoing coronary artery bypass grafting through median sternotomy with or without cardiopulmonary bypass.

METHODS

Forty-four consecutive patients were studied. Patients were selected for off-pump coronary artery bypass grafting whenever complete revascularization was technically feasible. There were no differences between the two groups with respect to age, sex, symptoms, or functional class. Plasma levels of tumor necrosis factor-alpha, interleukin (IL)-6, IL-8, and IL-10 were measured before the operation, at the end of the procedure, and 2, 4, 8, 24, and 48 hours thereafter. Levels of the MB isoenzyme of creatine kinase and cardiac troponin-I were also measured after the operation.

RESULTS

The number of grafts was 2+/-0.7 in the off-pump group (n = 18) and 3+/-0.8 in the cardiopulmonary bypass group (n = 26). There were no deaths or major complications in either group. Levels of tumor necrosis factor-alpha were low in both groups. No significant intergroup differences were noted regarding serial IL-6 measurements. However, IL-8 and IL-10 levels after the operation were lower in the off-pump group (IL-8, 4+/-1 versus 38+/-12 pg/mL, p < 0.01; IL-10, 5+/-2 versus 191+/-33 pg/mL, p < 0.001). Whereas postoperative creatine kinase-MB values were similar in the two groups, cardiac troponin-I levels were significantly lower in the off-pump group (8 hours, p < 0.005; 24 hours, p < 0.02, respectively). Moreover, cardiac troponin-I values 24 hours after operation correlated strongly with IL-8 levels (r = 0.61, p < 0.005), indicating that the degree of myocardial injury may be related to IL-8 production.

CONCLUSIONS

Compared with conventional coronary artery bypass grafting, coronary revascularization without cardiopulmonary bypass is associated with reduced cytokine responses and less myocardial injury.

[The development of an intelligent vision testing instrument]

The paper introduces an intelligent vision testing instrument, which works on automatic method or manual method. The examinee inputs his or her judgement about the direction of the letter "E" with remote control. The system examines and judges the examinee's judgement, and then prints the testing report. The vision testing range is from logarithm vision 3.0 to 5.3. The distance between examinee and optometer can be measured automatically by the system with infrared and ultrasonic testing functions and a good accuracy.

Does steroid pretreatment increase endotoxin release during clinical cardiopulmonary bypass?

OBJECTIVE

The mechanism involved in the endotoxemia frequently recognized during cardiopulmonary bypass remains unclear. It has also been suggested that endotoxin levels were higher in steroid-pretreated patients undergoing cardiopulmonary bypass.

METHODS

Twenty patients undergoing cardiopulmonary bypass were randomly pretreated with steroids (methylprednisolone, 30 mg/kg) or placebo. Blood samples for endotoxin measurement were drawn simultaneously from the superior and inferior venae cavae before heparin administration, 5 and 50 minutes after the onset of bypass, 5 minutes after aortic declamping, at the end of bypass, and 1, 2, and 20 hours after the end of cardiopulmonary bypass.

RESULTS

The perioperative variables in the two groups were similar. Blood endotoxin levels were higher in the inferior vena cava than in the superior vena cava immediately after the onset of bypass. Endotoxin levels in inferior vena cava blood were significantly lower in steroid-pretreated patients than those in patients not receiving steroids.

CONCLUSIONS

Endotoxin is released during cardiopulmonary bypass from the region drained by the inferior vena cava. Steroid pretreatment may actually reduce endotoxin release during bypass.

A Chinese thoracic surgeon and his two decisions

Doctor Wu Ying-Kai is known to many in the thoracic surgical academia worldwide. This article focuses on the two decisions he made at the ages of 33 and 70 that profoundly influenced the development of thoracic and cardiovascular medicine in a country with one quarter of the world population. His successful career was gauged not so much by the position he achieved, but by the obstacles he had to overcome to achieve it.

Ministernotomy for aortic valve replacement in a patient with osteogenesis imperfecta

Open heart operations in patients with osteogenesis imperfecta are associated with increased morbidity and mortality resulting from tissue friability and bone brittleness. We used a ministernotomy approach for aortic valve replacement in a patient with osteogenesis imperfecta, with clear benefits and a satisfactory outcome.

Can cardioplegia management influence cytokine responses during clinical cardiopulmonary bypass?

BACKGROUND

Cytokines play an important role in the inflammatory response associated with cardiopulmonary bypass (CPB) and may contribute to postoperative complications. Although it has been shown that the production of tumor necrosis factor a (TNF-a) and interleukin (IL)-6 were higher following normothermic CPB than hypothermic CPB, whether different cardioplegic management could influence the release of cytokines remains unknown.

METHODS

We compared the blood concentrations of four cytokines (TNF-a, IL-6, IL-8, and IL-10) in two groups of patients undergoing complete revascularization with CPB in the same study period. Seventeen patients received cold crystalloid cardioplegia at a Belgian center (group-CC), while 21 patients received warm blood cardioplegia at a center in Hong Kong (group-WB). Blood samples were collected before and after surgery in each patient.

RESULTS

There were no differences between the 2 groups in terms of age, sex ratio, number of grafts, duration of CPB and aortic crossclamping. All patients survived their hospital stay. The levels of TNF-a, IL-6 and IL-8 after surgery were higher in group-CC than in group-WB. However, IL-10 levels were significantly lower at the end of surgery in group-CC than in group-WB.

CONCLUSIONS

Our data suggest that the use of warm blood cardioplegia, rather than cold crystalloid cardioplegia, may reduce the inflammatory response to CPB. This observation warrants future randomized investigation to determine its clinical relevance.

Routine intraoperative angiography improves the early patency of coronary grafts performed on the beating heart

OBJECTIVES

The techniques of performing coronary revascularization without cardiopulmonary bypass are rapidly evolving. However, concern remains regarding the accuracy of coronary artery anastomoses performed on the beating heart. This report reviews the use of intraoperative angiography in the critical appraisal of "off-pump" coronary artery bypass graft (CABG) surgery.

PATIENTS

Intraoperative angiography was performed in 24 consecutive patients undergoing CABG surgery without cardiopulmonary bypass. In all, 24 left internal mammary artery (LIMA) grafts and 18 saphenous vein bypass grafts were assessed for patency, anastomosis quality, distal and proximal runoff, and correct placement.

RESULTS

All of the saphenous vein-to-coronary artery anastomoses were widely patent, although two patients (8%) required revision of their LIMA grafts on the basis of angiographic findings.

CONCLUSION

Intraoperative angiography permits the surgeon to immediately appraise the CABG and to revise, if necessary, any graft abnormality, thus potentially eliminating the need for early repeated surgery. The practice of routine intraoperative angiography is likely to improve the outcome of CABG surgery on the beating heart.

[Effect of shen-dong-xin-bao oral liquid on IFN-induction and NK cell activity in CVB3m infected mice]

OBJECTIVE

Our aim was to investigate the effect of Shen-dong-xin-bao oral liquid on IFN-induction and NK cell activity in mice with coxsackie virus B3(CVB3m) infection in different infective stages.

METHODS

The level of serum interferon (IFN) and the activity of natural killer (NK) cells in CVB3m induced myocarditis in mice were determined. Natural killer cell cytolytic activity was tested by MTT method and interferon titers by 50% microcytopathic effect assay.

RESULTS

In the infected mice fed with 30 g/kg or 12 g/kg per day of Shen-dong-xin-bao oral administration for 10d and 20d, the mean titers of IFN were markedly higher than that in untreated infected group, P < 0.05. The NK cell activity in treated infected groups was also prominently higher than that in untreated infected group, especially on 20d, P < 0.05.

CONCLUSION

This results demonstrate that administration of Shen-dong-xin-bao oral liquid possesses enhancement of antiviral immunocompetent action.

Video-assisted thoracic surgery: a renaissance in surgical therapy

Within a few years, video-assisted thoracic surgery (VATS) has become the accepted or preferred approach over a wide range of thoracic procedures. The authors review the development of this technique, the basic operative strategies and the current surgical indications. Technical pitfalls and future developments are also discussed.

A survey on partial left ventriculectomy in the Asia-Pacific region

BACKGROUND

There has been increasing interest in partial left ventriculectomy as a new therapy for end-stage heart failure. Because the most significant impact of this development is likely to be in regions where heart transplantation is largely unavailable, we conducted a survey among a group of cardiac surgeons based in the Asia-Pacific region to evaluate their overall views on partial left ventriculectomy procedures.

METHODS

A questionnaire was sent to surgeons from 65 major institutions in 17 countries and regions in the Asia-Pacific. Questions examined current demographics and opinions regarding potential application and future prospects of this operation.

RESULTS

Surveyed surgeons were based in equal proportions in academic, government, and private practice institutions. One third of respondents have already performed partial left ventriculectomy operations, largely in small numbers. In total, 86 procedures were performed with 75% hospital survival rate. Failures were thought to be caused by limited knowledge about patient selection criteria and lack of experience with operative technique and perioperative care. The majority of respondents believe that partial left ventriculectomy is potentially a valuable intervention and intend to perform more cases. Nevertheless, most surgeons identified the need to have larger clinical experience, to perform randomized trials against other therapeutic modalities, and to improve perioperative care.

CONCLUSIONS

Although all surgeons recognize that more knowledge is needed before partial left ventriculectomy becomes a standard procedure, it is clear from this survey that the procedure has rapidly gained interest, with more surgeons seeking to learn it.

Video-assisted thoracoscopic thymectomy

Video-assisted thoracoscopic surgery (VATS) provides a new, alternative approach to thymectomy and has several advantages over the other established techniques. However, even among surgeons using this approach, there are differences in the actual technique. We prefer the right approach using conventional instruments. The rationale behind our technique is discussed.

Is video-assisted thoracoscopic lobectomy a unified approach?

BACKGROUND

Few surgeons worldwide currently perform video-assisted thoracoscopic (VAT) lobectomy. We conducted a questionnaire survey of this selected group of surgeons to gain insight into their current practice.

METHODS

A survey with 25 questions on VAT lobectomy including operative approaches, techniques, its role in their practice, and limitations were mailed to 45 thoracic surgeons worldwide who are believed to perform this operation.

RESULTS

Thirty-three completed questionnaires were analyzed. Among those surgeons practicing VAT lobectomy, the vast majority work in an academic or government institution and have at least 5 years of practice experience. Two thirds reported that at least 40% of all their thoracic procedures are currently performed using VAT techniques. However, considerable variations exist regarding preference for VAT lobectomy (one third uses VAT techniques in less than 10% of all lobectomies performed, whereas another third uses it in more than 40% of lobectomies), their approaches to mediastinal and hilar lymph nodes, and their operative techniques. The latter range from a purely endoscopic technique to one that is more appropriately termed minithoracotomy with video-assistance when the surgeons operate primarily by looking through the utility thoracotomy. There were no significant differences in the practices of surgeons working in different continents, except that Asian surgeons were more likely to use suture ligation as opposed to a staple-cutter on pulmonary vessels.

CONCLUSIONS

Video-assisted thoracoscopic lobectomy is not a unified approach. Considerable variations exist among the small group of surgeons performing this procedure, in their approach to surgical oncology as well as the operative technique. Distinctions in these different operative approaches must be made before one can make a meaningful comparison of results. Different terms should probably be introduced to further clarify the exact techniques used.

[Investigation and identification of varieties of wulingzhi in Qinghai Province]

This paper reports the investigation and identification of varieties of Wulingzhi used as drugs in Qinghai province. The results show Wulingzhi varieties from the province and the parts of northwest districts are different with the Wulinzhi recorded in China Pharmacopoeia, which has itself special varieties and identified standard, their originals are the excrements from Petaurista xanthotis, Ochotona erythrotis, O. curzoniae. O. daurica and O. causus.

Inflammatory response to cardiopulmonary bypass: mechanisms involved and possible therapeutic strategies

BACKGROUND

Recent study of the inflammatory reactions occurring during and after cardiopulmonary bypass (CPB) has improved our understanding of the involvement of the inflammatory cascade in perioperative injury. However, the exact mechanisms of this complex response remain to be fully determined.

METHODS

Literature on the inflammatory response to CPB was reviewed to define current knowledge on the possible pathways and mediators involved, and to discuss recent developments of therapeutic interventions aimed at attenuating the inflammatory response to CPB.

RESULTS

CPB has been shown to induce complement activation, endotoxin release, leukocyte activation, the expression of adhesion molecules, and the release of many inflammatory mediators including oxygen-free radicals, arachidonic acid metabolites, cytokines, platelet-activating factor, nitric oxide, and endothelins. Therapies aimed at interfering with the inflammatory response include the administration of pharmacologic agents such as corticosteroids, aprotinin, and antioxidants, as well as modification of techniques and equipment by the use of heparin-coated CPB circuits, intraoperative leukocyte depletion, and ultrafiltration.

CONCLUSIONS

Improved understanding of the inflammatory reactions to CPB can lead to improved patient outcome by enabling the development of novel therapies aimed at limiting this response.

[Studies on expansion ex vivo of murine bone marrow cells and its hematopoietic reconstitution capacity]

OBJECTIVE

To investigate the effects of stem cell factor (SCF) in combination with interleukin-1 (IL-1) or/and interleukin-3 (IL-3) on ex vivo expansion of 5FU treated bone marrow cells and hematopoietic recovery in lethally irradiated mice transplanted with the expanded cells.

METHODS

5FU treated bone marrow cells (d3-5FU-BMC) were cultured in a cytokines-containing medium, and the net increments of CFU-GM and high proliferative potential colony forming cell (HPP-CFC) were evaluated.

RESULTS

CFU-GM increased by 33.7 +/- 18.1- or 18.1 +/- 6.3- fold, and HPP-CFC by 17.8 +/- 10.5- or 12.7 +/- 9.1- fold, respectively, in cultures containing SCF with IL- or IL-3, as compared with that in control; while SCF alone had little effect. Compared with fresh d3-5FU-BMC, transplantation of the expanded bone marrow cells accelerated the recovery of recipients' peripheral blood cell counts by 1 approximately 3 days and increased the survival rate of the transplanted animals (d3-5FU-BMC group 50% vs expansion group 8U approximately 100%).

CONCLUSION

SCF in combination with IL-1 or IL-3 synergetically ex vivo expands hematopoietic cells. Transplantation of the expanded bone marrow cells accelerates the recipient's hematopoietic reconstitution.