Cannulation of ascending aorta for long-term membrane oxygenator support

The association of CTLA-4 A49G polymorphism with colorectal cancer risk in a Chinese Han population

Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is expressed in T cells and plays an important role in the regulation of T cell. CTLA-4 has long been considered to be associated with various kinds of diseases. With the attempt to examine the association between CTLA-4 A49G polymorphism and colorectal cancer risk in a Chinese Han population, we employed TaqMan assay to genotype the CTLA-4 A49G polymorphism in 311 colorectal cancer cases and 389 cancer-free controls. We found evidence of the association between CTLA-4 A49G polymorphism and colorectal cancer risk (GG vs. AA: OR = 2.01, 95% CI = 1.29-3.07, P = 0.002; GA vs. AA: OR = 2.32, 95% CI = 1.53-3.57, P = 0.001; GA + GG vs. AA: OR = 2.16, 95% CI = 1.46-3.21, P = 0.001). Next, we performed a meta-analysis to comprehensively examine the association between CTLA-4 A49G polymorphism and colorectal cancer risk. We found a significant association between CTLA-4 A49G polymorphism and colorectal cancer risk among Asians, which is consistent with our result. However, we found no evidence for the association between CTLA-4 A49G polymorphism and colorectal cancer risk among Caucasians. In conclusion, we demonstrated that the CTLA-4 A49G polymorphism increased the susceptibility of colorectal cancer in Asian population.

Association between CTLA-4 60G/A and -1661A/G polymorphisms and the risk of cancers: a meta-analysis

PURPOSE

CTLA-4 is one of the most fundamental immunosuppressive cotykines which belongs to the immunoglobulin super-family, and is expressed mainly on activated T cells. Previous studies have reported the existence of CTLA4 60G/A and CTLA4 -1661A/G polymorphism in cancers. However, the effects remain conflicting. Hence, we performed a meta-analysis to investigate the association between these polymorphisms and cancer risk.

METHODS

We searched the Pubmed and Web of Science databases until October 24, 2013 to obtain relevant published studies. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for the relationship between CTLA4 gene polymorphisms and cancer susceptibility were calculated by stata 11 software. Heterogeneity tests, sensitivity analyses and publication bias assessments were also performed in our meta-analysis.

RESULTS

A total of 22 articles comprising 31 case-control studies concerning the CTLA-4 60G/A and CTLA-4 -1661A/G polymorphisms were included in the meta-analysis. The pooled results suggested the CTLA-4 60G/A polymorphism was significantly associated with an increased skin cancer risk (AA vs. GG: OR = 1.32, 95%CI = 1.09-1.59; AA vs. GA+GG: OR = 1.26, 95%CI = 1.07-1.48). For CTLA-4 -1661 A/G polymorphism, the results showed that the CTLA-4 -1661A/G polymorphism was significantly associated with an increased cancer risk (GA vs. AA: OR = 1.44, 95%CI = 1.13-1.82; GA+GG vs. AA: OR = 1.35, 95%CI = 1.07-1.69; G vs. A: OR = 1.21, 95%CI = 1.01-1.47), especially in gastric cancer, breast cancer, other cancers and in Asians population subgroups.

CONCLUSION

Our meta-analysis suggests that the CTLA-4 -1661A/G polymorphism is a potential factor for the susceptibility of cancer, especially in gastric cancer, breast cancer and other cancers, and the CTLA-4 60G/A polymorphism is significantly associated with increased skin cancer risk. The effect of the CTLA-4 -1661A/G polymorphism on cancer susceptibility especially exists in Asians and population based subjects.

Extracorporeal membrane oxygenator support in a case of severe status asthmaticus

Support with extracorporeal membrane oxygenation (ECMO) can sustain life for a substantial period of time, but the role of long-term ECMO support is limited. The National Institutes of Health ECMO collaborative study revealed no significant reduction in mortality in adults with severe respiratory distress syndrome treated with ECMO. The value of ECMO in the treatment of transient, severe acute respiratory insufficiency has been demonstrated in patients after cardiac operations, in patients with Pneumocystis carinii pneumonia, and in patients following trauma. We present an example of refractory respiratory failure in a young asthmatic with massive atelectasis in whom the institution of ECMO allowed us to perform adequate pulmonary lavage. It resulted in improvement in gas exchange and the patient's survival.

Oxygenation of the cerebral and coronary circulation with right axillary artery perfusion during venoarterial bypass in primates

The effectiveness of right axillary artery perform in delivering oxygenated blood to the cerebral and coronary circulation during venoarterial bypass in primates was studied. Both right and left common carotid flow measurements and arterial gas measurements revealed high flows and elevated PO2 levels. Incomplete mixing in the ascending aorta was observed from cineangiograms taken at various pump oxygenator flows in 1 animal. The results demonstrated that the brain receives excellent oxygenation at all bypass levels. However, the coronary circulation is perfused primarily by blood ejected from the left ventricle and receives only minimal contribution of well-oxygenated blood from the pump oxygenator circuit. Therefore, the heart may suffer prolonged hypoxemia during long-term venoarterial bypass for acute respiratory insufficiency.

Pulmonary hypertension in severe acute respiratory failure

We repeatedly assessed pulmonary and systemic hemodynamics in 30 patients undergoing therapy for severe acute respiratory failure of diverse causes. Pulmonary-artery hypertension and elevated pulmonar vascular resistance were observed in all patients after correction of systemic hypoxemia. Increasing pulmonary blood flow by isoproterenol infusion or decreasing pulmonary blood flow by partial bypass of the right side of the heart minimally altered pulmonary-artery pressure. Although neither elevated pulmonary vascular resistance nor low cardiac index reliably predicted death, survivors had preogressive decreases of pulmonary vascular resistance with time, whereas nonsurvivors tended to maintain or increase pulmonary vascular resistance. Right ventricular stroke-work index was markedly elevated in all patients. The work load imposed upon the right ventricle by elevation of pulmonary vascular resistance may be a factor limiting survival in severe acute respiratory failure.

Control, monitor and alarm system for clinical application of a membrane oxygenator

Membrane oxygenators, now commercially available, are undergoing clinical trials as long-term (days) respiratory support devices for patients in potentially reversible respiratory failure. However, these devices must be used in an integrated system of controls, monitors and alarms if they are to be reliable and easy to operate in the clinical environment. This paper describes such a system. The tubing circuits for blood and for oxygen are described first. Next, details of the blood pump controls are presented. The system features servo control of pump speed to match blood inflow, and deactivation of the pump in the case of excessive output pressure. Gas circuit controls are described which allow the independent adjustment of both oxygen flow through the gas phase of the membrane lung and oxygen pressure developed at the inlet gas port. Audible alarms are provided for low blood inflow to the system, excessive blood outflow pressure, changes in oxygen flow and failure of the electric power supply to the system. In addition to pressure and flow monitors in the blood and gas circuits, blood oxygen saturation is continuously monitored at both input and output of the system. The membrane oxygenator system has proved to be reliable and easy to operate in both animal and human long-term perfusions.

The source of coronary perfusion during partial bypass for extracorporeal membrane oxygenation (ECMO)

The proper siting of cannulas to return oxygenated blood to patients on long-term membrane oxygenator support is as yet undecided. This experimental study on adult sheep shows the problems of obtaining perfusion of the coronary arterial tree when blood is returned to the ascending aorta. Our 11 experiments demonstrate that the coronary arterial tree is perfused with blood ejected from the left ventricle except during very high bypass flows (85% bypass) or when the aortic valve is rendered incompetent.