Impact of coronary artery bypass surgery on ischemic mitral regurgitation

INTRODUCTION

To determine the course of ischemic mitral regurgitation (IMR) after coronary artery bypass grafting (CABG), and evaluate preoperative factors which predict the development of the severity of IMR after CABG.

METHODS

Between 1992-2005, 1995 patients underwent CABG and 170 of them had IMR. Data of 131 patients were retrospectively analyzed and living patients (n = 112) had a clinical follow-up visit. The mean follow-up time was 6.5 years.

RESULTS

At the time of CABG, 66% of the 131 cases analyzed had mild, 31% had moderate, and 3% had severe IMR. At the time of follow-up, 52% of patients had either no IMR or mild IMR, 27% had moderate IMR, 6% had severe IMR and 15% suffered from cardiac related death. During follow-up IMR grade reduced in 25% of study patients. None of the patient had re-operation due to the mitral regurgitation. Multivariate analysis showed that left ventricular ejection fraction (LVEF) was an independent predictor of good prognosis (O.R. 1.4, 95% C.I. 1.15-1.83/ 10% increase of LVEF, p = 0.02).

CONCLUSION

Half of the patients, who have IMR at the time of CABG, have no IMR or only mild IMR postoperatively. Good LVEF adds to the probability that CABG only can reduce IMR.

Biophysical characteristics of neurotensin polyplex for in vitro and in vivo gene transfection

Previously we improved the neurotensin (NT)-polyplex by the coupling of HA2 fusogenic peptide (FP) and Vp1 SV40 karyophilic peptide (KP). We now report the proportion of [(125)I]-NT, [(3)H]-FP, and poly-l-lysine (PLL) in the NT-polyplex, and some of its biophysical properties. We concluded that the most efficient NT-polyplex comprised 1 NT, 4 FP, and 2 PLL molecules. Electrophoresis revealed that high acidity is detrimental for NT-polyplex stability. Electron microscopy and electrophoresis studies showed that 6 muM KP and 1% serum condensed the plasmid DNA (pDNA) before the appearance of toroid structures. Four plasmids were used to evaluate the transfection efficiency. In vitro, maximum expression was produced at molar ratios (pDNA : [(125)I]-NT-[(3)H]-FP-PLL conjugate) of 1:34 for pEGFP-N1 and 1:27 for pECFP-Nuc. Cotransfection of those plasmids was attained at their optimum molar ratios. In vivo, maximum expression of the pDAT-BDNF-flag in dopamine neurons was produced at a 1:45 molar ratio, whereas that of pDAT-EGFP was at 1:20. The NT-polyplex in the presence of 1 muM SR-48692, an NT-receptor specific antagonist, and untargeted polyplex did not cause transfection in vivo demonstrating the specificity of gene transfer via NT-receptor endocytosis. This information is essential for synthesizing an efficient NT-polyplex that can provide a useful tool for specific gene transfection.

HCV core protein localizes in the nuclei of nonparenchymal liver cells from chronically HCV-infected patients

Understanding the mechanism of hepatitis C virus (HCV) pathogenesis is an important part of HCV research. Recent experimental evidence suggests that the HCV core protein (HCcAg) has numerous functional activities. These properties suggest that HCcAg, in concert with cellular factors, may contribute to pathogenesis during persistent HCV infection. HCV is capable of infecting cells other than hepatocytes. Although the extrahepatic cellular tropism of HCV may play a role in the pathophysiology of this infection, the precise biological significance of the presence of HCV components in different liver cell types presently remains to be established. In this study, HCcAg was detected in nonparenchymal liver cells of six patients out of eight positive for serum HCV RNA. Immunostaining with anti-HCcAg mAbs revealed the presence of this protein in different liver cell types such as lymphocytes, Kupffer, polymorphonuclear, pit, endothelial, stellate, and fibroblast-like cells. Interestingly, HCcAg was immunolabeled not only in the cytoplasm but also in the nucleus of these cells. Remarkably, HCcAg co-localized with large lipid droplets present in stellate cells and with collagen fibers in the extracellular matrix. Moreover, HCcAg was immunolabeled in bile canaliculus suggesting the involvement of the biliary system in the pathobiology of HCV. Data suggest that nonparenchymal liver cells may constitute a reservoir for HCV replication. Besides, HCcAg may contribute to modulate immune function and fibrosis in the liver as well as steatosis.

Nuclear localization of nucleocapsid-like particles and HCV core protein in hepatocytes of a chronically HCV-infected patient

Little is known about the life cycle of hepatitis C virus. Determination of the subcellular localization of HCV proteins may contribute to our understanding of the in vivo functions of the viral proteins. HCV core protein regulates multiple functions in host cells and it has been detected both in the cytoplasm and in the nucleus using different expression systems. In this study, nucleocapsid-like particles were observed in the nucleus of hepatocytes from a chronically HCV-infected patient. They were similar in size and shape to those of HCV core-like particles purified from recombinant Pichia pastoris cells. In addition the HCV core protein was detected not only in the cytoplasm but also in the nucleus and nucleolus of hepatocytes by immunoelectron microscopy. This is the first report showing nuclear localization of HCV core protein and nucleocapsid-like particles in hepatocytes during in vivo HCV infection.

Structured HCV nucleocapsids composed of P21 core protein assemble primary in the nucleus of Pichia pastoris yeast

The relationship between HCV core protein (HCcAg) processing and the structural composition and morphogenesis of nucleocapsid-like particles (NLPs) produced in Pichia pastoris cells was studied. At early stages of heterologous expression, data suggest that HCcAg (in the P21 form) was transported soon after its synthesis in the cytoplasm into the nucleus. HCcAg assembly into nucleocapsid-like particles with 20-30 nm in diameter took place primary in the cell nucleus. However, at later stages, when P21 and P23 forms were co-detected, data suggest that new assembly of nucleocapsid particles containing P21 possibly occurs at ER membranes and in the cytoplasm. This is the first report showing that structured HCV NLPs composed of P21 core protein assemble primary in the nucleus of P. pastoris yeast.

Conduction defects after coronary artery bypass grafting--a disappearing problem?

BACKGROUND AND AIMS

To evaluate the incidence of conduction defects (CDs) following coronary artery bypass grafting (CABG) in three different patient populations, to assess the etiologic factors associated with CDs, and to find out their effect on immediate postoperative outcome of the patient.

MATERIAL AND METHODS

Three patient populations were prospectively studied: cohort A consisted of 180 CABG-patients operated between 1990-91, cohort B of 100 patients operated during the year 1993 and cohort C of 118 patients operated from April 1997 to June 1997. Cold crystalloid cardioplegia was used throughout the study years. In the first cohort A, two separate cavae were cannulated and clamped, venting through the right upper pulmonary vein was used, iced cold saline was used in pericardium, and cardioplegia was given until a myocardial temperature of 10-15 degrees of Celcius was attained. In the two later cohorts, two-stage venous cannula and aortic root venting were used and cardioplegia was given only until the activity of the myocardium stopped. Proximal anastomoses were performed after aortic declamping in cohort A, and during aortic occlusion in the two later cohorts.

RESULTS

The incidence of permanent CDs in cohort A was 36%, in cohort B 5% and in cohort C 1%. Permanent atrioventricular (AV-) and left-sided blocks disappeared first. Left main coronary artery stenosis and low myocardial temperatures were associated with CDs. Patients with permanent CDs had more often low cardiac output after the operation, their values of cardiac enzymes were higher, and they had more often postoperative infarction than patients without CDs.

CONCLUSIONS

The disappearance of all long lasting AV- and left-sided blocks simultaneously with decreasing plasma levels of cardiac enzymes is evidence that protection of both conduction tissue and myocardium had considerably improved in the two later cohorts. Giving cardioplegia in smaller amounts and more often at the same time when raising the general temperature during perfusion were the main reasons for the disappearance of postoperative CDs.

Cutaneous withdrawal reflexes of the upper extremity

We characterized reflexes of the upper limb elicited by electrical stimulation of the fingers. Surface electromyogram (EMG) was recorded from several upper extremity muscles, and a finger was stimulated through paired ring electrodes. A train of 4-10 shocks at a frequency of 300 Hz and an intensity 4-6 times the perceptual threshold was the most effective stimulus for evoking EMG activity in relaxed arm muscles. Habituation was prominent. Latencies of EMG activity were <100 ms for most proximal and forearm muscles, and at least 40 ms prior to voluntary withdrawal movements. The timing of EMG activity in arm muscles was similar to that of the E2 component of the cutaneomuscular reflex evoked in these same muscles during contraction, and coincided with a silent period in active hand muscles. We conclude that cutaneous stimuli to the fingers activate a complex motor pattern that tends to withdraw the hand at the same time the grasp is released.

Percutaneous transluminal angioplasty in femoral artery occlusions: primary and long-term results in 107 claudicant patients using femoral and popliteal catheterization techniques

To assess the impact of percutaneous transluminal angioplasty (PTA) of occluded femoral arteries, a prospective study of 107 claudicant patients was performed. A total of 117 limbs were treated and were followed for 1-36 months; the mean length of treated occlusions was 7.4 cm (range 2-25 cm). Eighty-nine recanalizations were performed using antegrade femoral and 28 using the retrograde popliteal catheterization technique. With logistic regression a short length of occlusion correlated favourably with early success. Including rePTAs and applying standardized criteria, survival analysis with the Kaplan-Meier method revealed a 3-year secondary patency rate of 55% for all the treated limbs. The following factors had negative influence on primary patency after successful recanalization; presence of soft thrombotic material in the recanalized artery segment and the presence of focal dissections after PTA. In univariate and multiple logistic regression analysis, male gender and a lesser extent of the atherosclerotic disease (assessed by the number of diseased vessels in the treated limb) correlated with a lower frequency of PTA procedure complications. There was no statistically significant difference in the complications, in the primary success or in the long-term results using either the femoral or popliteal route. However, the popliteal approach improved the early success of the originally antegrade access group by 6% and increased by about one-fifth the number of patients considered technically feasible for PTA in femoral artery occlusions. PTA can be used in femoral artery occlusions up to 10 cm long and it is especially suitable in femoral artery occlusions not exceeding 5 cm in length. PTA can be tried in femoral artery occlusions exceeding a length of 10 cm if operative treatment is not suitable.

Intermittent mitral regurgitation and pulmonary edema after aortic valve replacement

We report intermittent mitral valve regurgitation with 17 acute pulmonary edemas over a 16-month period after aortic valve replacement due to combined aortic valve disease in a 51-year-old man. The mechanism of mitral regurgitation was explained by the relatively large size of the prosthetic valve which had had to be sutured partly below the aortic annulus. It was suspected to interfere with the closure of the mildly diseased mitral valve when under pressure or subjected to volume loadings of the left ventricle which provoked free mitral regurgitation. There was no recurrence of pulmonary edema in the 50 months following mitral valve replacement.

Transepicardial defibrillation dose response: current versus energy

In pentobarbital-anesthetized dogs, we compared the relative efficacy of current versus energy in applying the dose response method in transcardiac defibrillation. Damped sinusoidal shocks via epicardial patches were administered by a custom defibrillator permitting precise current delivery. Following the establishment of an initial estimated defibrillation threshold for energy and current, the dose response method was performed with regard to either energy defibrillation threshold (group E, n = 8) or current defibrillation threshold (group C, n = 8). Two sequential sets (I, II) of shocks (21 shocks each) were delivered in random order at each of seven doses: 0.55, 0.70, 0.85, 1.00, 1.15, 1.30, and 1.45 x defibrillation threshold. Data were subjected to nonlinear logistic regression analysis. There were no significant differences between sets I and II in either groups E or C for resistance or for raw and normalized values associated with 50% and 80% success expressed as energy, current, or voltage. Correlation coefficients (r) associated with nonlinear logistic regression analysis were significantly different for normalized current and energy for group E (0.70 +/- 11 and 0.71 +/- 12) compared to group C (0.86 +/- 0.60 and 0.88 +/- 0.06). The difference, however, could be explained by a significantly narrower range of normalized current values tested in group E (0.79 to 1.31) versus group C (0.54 to 1.46). Thus, when resistance does not change, transcardiac current offers limited advantage over energy when applying a dose response method. The efficacy of nonlinear logistic regression analysis depends upon an adequate dose range.

Effects of cytochalasin B and of deoxyglucose on phagocytosis-related changes in membrane potential in rat peritoneal macrophages

Cytochalasin B (CB) and deoxyglucose alter the electrical responses of the plasma membrane of rat peritoneal macrophages to the presence of phagocytosable latex particles. With both agents, instead of the initial hyperpolarization we previously observed, there is a depolarization. In the case of cytochalasin B (CB) this is followed by a gradual repolarization to the initial resting level, whereas with deoxyglucose the membrane eventually does hyperpolarize. One possible interpretation is that plasma membrane receptors mediate the depolarization in response to phagocytosable particles, but that normally this is masked by other changes effected here by the agents we used.

Hyperpolarisation of rat peritoneal macrophages phagocytosing latex particles

The changes that take place in the plasma membrane during endocytosis are still poorly understood. Studies of the electrical properties and related permeabilities of cells during pinocytosis and phagocytosis should provide insight into these changes. This approach has not been much exploited, although there have been a few relevant reports. For example, induction of pinocytosis in amoebae produces a marked decrease in plasma membrane resistance, and exposure of polymorphonuclear leukocytes to phagocytosable particles can engender alterations in ionic permeabilities. The present report demonstrates that the induction of phagocytosis in rat peritoneal macrophages is accompanied by a sustained hyperpolarisation of the cells.