The C-terminal binding protein (CTBP-1) regulates dorsal SMD axonal morphology in Caenorhabditis elegans

C-terminal binding proteins (CtBPs) are transcriptional co-repressors which cooperate with a variety of transcription factors to repress gene expression. Caenorhabditis elegans CTBP-1 expression has been observed in the nervous system and hypodermis. In C. elegans, CTBP-1 regulates several processes including Acute Functional Tolerance to ethanol and functions in the nervous system to modulate both lifespan and expression of a lipase gene called lips-7. Incorrect structure and/or function of the nervous system can lead to behavioral changes. Here, we demonstrate reduced exploration behavior in ctbp-1 mutants. Our examination of a subset of neurons involved in regulating locomotion revealed that the axonal morphology of dorsal SMD (SMDD) neurons is altered in ctbp-1 mutants at the fourth larval (L4) stage. Expressing CTBP-1 under the control of the endogenous ctbp-1 promoter rescued both the exploration behavior phenotype and defective SMDD axon structure in ctbp-1 mutants at the L4 stage. Interestingly, the pre-synaptic marker RAB-3 was found to localize to the mispositioned portion of SMDD axons in a ctbp-1 mutant. Further analysis of SMDD axonal morphology at days 1, 3 and 5 of adulthood revealed that the number of ctbp-1 mutants showing an SMDD axonal morphology defect increases in early adulthood and the observed defect appears to be qualitatively more severe. CTBP-1 is prominently expressed in the nervous system with weak expression detected in the hypodermis. Surprisingly, solely expressing CTBP-1a in the nervous system or hypodermis did not restore correct SMDD axonal structure in a ctbp-1 mutant. Our results demonstrate a role for CTBP-1 in exploration behavior and the regulation of SMDD axonal morphology in C. elegans.

Identification of mutations and evaluation of cardiomyopathy in Turkish patients with primary carnitine deficiency

Primary systemic carnitine deficiency (SCD) is an autosomal recessive disorder caused by defective cellular carnitine transport. Patients usually present with predominant metabolic or cardiac manifestations. SCD is caused by mutations in the organic cation/carnitine transporter OCTN2 (SLC22A5) gene. Mutation analysis of SLC22A5 gene was carried out in eight Turkish patients from six families. Six patients presented with signs and symptoms of heart failure, cardiomyopathy, and low plasma carnitine levels, five of them with concurrent anemia. A patient with dilated cardiomyopathy had also facial dysmorphia, microcephaly, and developmental delay. Tandem MS analyses in siblings of the patients revealed two more cases with low plasma carnitine levels. SCD diagnosis was confirmed in these two cases by mutation screening. These two cases were asymptomatic but echocardiography revealed left ventricular dilatation in one of them. Carnitine treatment was started before the systemic signs and symptoms developed in these patients. Mean value of serum carnitine levels of the patients was 2.63±1.92μmol/L at the time of diagnosis. After 1year of treatment, carnitine values increased to 16.62±5.11 (p<0.001) and all responded to carnitine supplementation clinically. Mutation screening of the OCTN2 gene study in the patients revealed two novel (p.G411V, p.G152R), and four previously identified mutations (p.R254X, p.R282X, p.R289X, p.T337Pfs12X). Early recognition and carnitine supplementation can be lifesaving in this inborn error of fatty acid oxidation.

Cardiovascular risk factors in hemodialysis and peritoneal dialysis patients

BACKGROUND

Cardiovascular disease (CVD) is the major cause of mortality and morbidity of hemodialysis (HD) and peritoneal dialysis (CAPD) patients. We aimed to investigate the cardiovascular risk factors and their correlation with CVD in groups of HD and CAPD patients.

METHODS

Thirty HD patients, 30 CAPD patients and 30 healthy controls were included in the study. Apolipoprotein A-l (apo A-l), apolipoprotein B (apo B), apolipoprotein(a) [Lp(a)] and high-sensitivity CRP (hs-CRP) were measured with a Beckman Coulter nephelometer, and homocysteine (Hcy) was determined with an Agilent HPLC analyzer. Lipid profile was determined with a Synchron LX 20 Pro analyzer.

RESULTS

Hcy levels were 41.9+/-19.4, 41.8+/-38.5 and 9.3+/-3.5 micromol/L; Lp(a) levels were 325+/-315, 431+/-367 and 130+/-97 mg/L; hs-CRP levels were 3.78+/-3.21, 4.34+/-3.39 and 2.07+/-1.67 mg/L; apo A1/apo B ratios were 1.46+/-0.6, 1.36+/-0.5 and 1.80+/-0.59; total cholesterol levels were 3.56+/-0.7, 4.84+/-1.1 and 4.39+/-0.5 mmol/L; triglycerides were 1.44+/-0.5, 1.60+/-0.8 and 0.85+/-0.5 mmol/L in the HD, CAPD and control groups, respectively.

CONCLUSION

HD and CAPD patients had higher Hcy, hs-CRP and Lp(a) levels and lower apo A/B ratios than controls. There was no significant difference between the HD and CAPD groups. Hypertension, age and hs-CRP showed a positive correlation with CVD.

Ischaemia-modified albumin elevation after percutaneous coronary intervention reflects albumin concentration rather than ischaemia

Background

Percutaneous coronary intervention (PCI) is accepted as a model of myocardial ischaemia in studies of ischaemia markers, especially of ischaemia-modified albumin (IMA). However, there is concern that IMA levels may reflect changes in albumin concentrations rather than myocardial ischaemia also during PCI.

Methods

Twenty-one consecutive patients (17 men and 4 women) undergoing single-vessel percutaneous coronary angioplasty were enrolled in the study. IMA and albumin levels were measured together with myoglobin, creatine kinase 2 and cardiac troponin I, before (Group 1), immediately after (Group 2) and 6 h after (Group 3) the procedure of PCI.

Results

The IMA levels of Group 2 were significantly higher than those of Group 1 and Group 3 ( P < 0.05 for both). However, correction of IMA by multiplying with the (individual albumin concentration of the patient/median albumin concentration of Group 1) ratio gave no statistical differences between the groups ( P > 0.05). There were strong negative correlations between IMA levels and albumin concentrations within individual groups ( r = −0.757, P < 0.001; r = −0.712, P < 0.001; and r = −0.705, P < 0.001 for Group 1, Group 2 and Group 3, respectively).

Conclusion

The results confirm the close dependency of IMA results on albumin concentrations. Therefore, IMA results reflect albumin concentrations rather than myocardial ischaemia also in PCI. This situation and lack of standard reference materials for the albumin cobalt binding assay can lessen the diagnostic performance of IMA.

Association between nitric oxide and oxidative stress in continuous ambulatory peritoneal dialysis patients with peritonitis

BACKGROUND

Peritonitis is a major complication in continuous ambulatory peritoneal dialysis (CAPD) patients, and the mechanisms involved in the pathology are important if the success rate of treatment strategies is to increase.

MATERIAL AND METHODS

A total of 50 CAPD patients (25 with 25 episodes of peritonitis and 25 with no clinical or laboratory signs of infection) were included in the study. Malondialdehyde (MDA) and nitric oxide (NO) metabolites in serum and dialysate effluents were determined.

RESULTS

The dialysate/serum (D/S) ratio of the NO metabolites and serum NO metabolite concentrations were significantly higher in the peritonitis group. Serum and dialysate MDA concentrations were also significantly higher in the peritonitis group. The D/S ratio of MDA was significantly higher in the control group.

CONCLUSIONS

Local peritoneal NO production and oxidative stress seem to increase in CAPD patients during the peritonitis attack.

Evidence of increased oxidative stress by simple measurements in patients with dilated cardiomyopathy

The heart cannot supply sufficient blood for tissue metabolic needs in patients with congestive heart failure. Hypoxia and organ hypoperfusion increase oxidative activity. It has been reported that free radicals are involved in the genesis of heart failure. The aim of this study was to assess the status of oxidative stress by simple measurements in patients with dilated cardiomyopathy of ischemic or idiopathic etiology. Eleven patients (8 M, 3 F, age range 32 to 65 years) with dilated cardiomyopathy of ischemic etiology and 12 patients (8 M, 4 F, age range 31 to 66 years) with dilated cardiomyopathy of idiopathic etiology were included in the study. A control group included 21 healthy subjects (12 M, 9 F, age range 25 to 67 years). Levels of thiobarbituric acid-reactive substances, total thiols, and fluorescent products of lipid peroxidation were measured in plasma/serum samples of patients and controls. No statistically significant differences were found between the two patient groups for the parameters studied (p>0.05). Levels of thiobarbituric acid-reactive substances and fluorescent products of lipid peroxidation were higher in both patient groups than in controls (p<0.05), whereas concentrations of total thiols were decreased (p<0.05). In conclusion, in patients with idiopathic or ischemic dilated cardiomyopathy, there are associated abnormalities of a range of markers of increased oxidative stress and lipid peroxidation. The plasma/serum constituents studied can be routinely measured in order to monitor patients during antioxidant therapy.

Myocardial hemodynamic and metabolic changes during abdominal insufflation with carbon dioxide

It is a well-known fact that laparoscopic procedures performed with carbon dioxide insufflation impair myocardial function. In this study, we aimed to determine the safety limitations of various intra-abdominal pressure values during abdominal insufflation with carbon dioxide. Of the 24 mongrel dogs, 6 were assigned to one of four different pressure groups (10, 15, 20 and 30 mm Hg), respectively. Cardiac output, right/left heart pressures, and the first derivative of ventricular pressure were monitored. Myocardial oxygen consumption, myocardial lactate/oxygen extraction, tissue lactate and adenosine triphosphate levels were determined. Measurements were performed initially as a control, at 15-min intervals during 1 h of insufflation and 1 h after desufflation. At 10 mm Hg carbon dioxide pressure, hemodynamic and metabolic parameters were not significantly different. Cardiac output decreased significantly in the 20 and 30 mm Hg groups (p < 0.05: 10, 15 vs. 20, 30 mm Hg). Although cardiac output did not change at 15 mm Hg, the dp/dt value was significantly reduced. Cardiac output at the 60th min was 1,960+/-75 ml/min in the 10 mm Hg group, 1,885+/-40 ml/min in the 15 mm Hg group, 1,770+/-45 ml/min in the 20 mm Hg group and 1,695+/-40 ml/min in the 30 mm Hg group. Myocardial oxygen consumption was reduced at 15, 20 and 30 mm Hg (p < 0.05: 10 vs. 15, 20 and 30 mm Hg). In the myocardial tissue, ATP decreased from 19+/-2 to 12+/-1.2 micromol/g at 15 mm Hg, from 19+/-1.9 to 9.4+/-1.3 micromol/g at 20 mm Hg and from 18+/-3.2 to 8.2+/-1.9 micromol/g at 30 mm Hg. Changes in hemodynamic and metabolic parameters of the heart are reversible and may not lead to any significant impairments in patients having normal cardiopulmonary function, but pose a risk in patients with respiratory disease and limited myocardial reserve.

Simplified retroperfusion system preserves the myocardial function during acute coronary artery occlusion

It is known that coronary venous retroperfusion restores the blood flow to the ischemic myocardium, resulting in reduction of infarct size and improvement in left-ventricular pump function. In this study, we used an animal model to investigate the effects of a simplified coronary venous retroperfusion system on myocardial hemodynamics. Twenty dogs were entered in this study. All dogs underwent fifteen minutes occlusion of the left anterior descending artery. For the rest of the experiment the dogs were randomized into two groups: the control group (n = 10) underwent a further 2 hours left anterior descending artery occlusion, then clamps were released and the animals were observed for 6 hours. In the retroperfusion group (n = 10) a simple aortocoronary sinus connection was made and retrograde perfusion achieved with an outflow of 43 +/- 6 ml/min. Retrograde coronary sinus perfusion was maintained for three hours and then the dogs were observed for six hours. Tissue adenosine triphosphate levels were 6 +/- 3 mumol/g in the control group and 12 +/- 2 mumol/g in the retroperfusion group (p < 0.05) 6 hours after reperfusion. Creatine phosphokinase levels were 99 +/- 11 IU/L in the control group and 42 +/- 8 IU/L in the retroperfusion group 6 hours after reperfusion (p < 0.05). Cardiac index was 63 +/- 4 ml/kg/min in the control group and 79 +/- 2 ml/kg/min in the retroperfusion group 6 hours after retroperfusion (p < 0.05). Left-ventricular stroke-work index at a pulmonary capillary artery wedge pressure of 20 mmHg was 0.54 +/- 0.06 g.m/kg in the retroperfusion group and 0.29 +/- 0.03 g.m/kg in the control group 6 hours after reperfusion (p < 0.05). It is concluded that myocardial hemodynamic and biochemical function can be preserved by simplified coronary sinus retroperfusion.

Increased oxidative stress in dilated cardiomyopathic heart failure

In the present study, we assessed oxidative stress in patients with dilated cardiomyopathy of ischemic or idiopathic etiology. For this reason we measured whole blood reduced glutathione, erythrocyte superoxide dismutase, susceptibility of erythrocyte membranes and erythrocytes to peroxidation, and SH content of erythrocyte membranes in 12 patients (8 men and 4 women, ages 31 to 66 years) with idiopathic dilated cardiomyopathy, in 11 patients (8 men and 3 women, ages 32 to 65 years) with ischemic dilated cardiomyopathy, and in 21 healthy volunteers (12 men and 9 women, ages 25 to 67 years). There was no statistically significant difference between the two patient groups for the indicators studied (P >0.05). Blood glutathione, erythrocyte superoxide dismutase, and membrane SH content of both groups of patients was decreased compared with controls (P <0.05), whereas erythrocyte and membrane susceptibility to peroxidation were increased (P <0.05). We conclude that patients with idiopathic or ischemic dilated cardiomyopathy exhibit abnormalities of a range of markers of increased oxidative stress. These abnormalities may contribute to contractile dysfunction, increased incidence of fatal arrhythmias, and sudden death.

Iloprost added to the cardioplegic solutions improves myocardial performance

A total of 12 mongrel dogs were divided into two equal groups. Six animals received IIoprost and the other 6 animals did not receive any additional treatment. In the Iloprost group, Iloprost was added to the cardioplegic solution (25 ng). Also, Iloprost was used (10 ng/kg/min.) 5 min. before and after cross-clamping. All cardiac output and biochemical measurements were evaluated before cross-clamp and 15 min., 1 h, and 4 h after cross-clamp. The measured dp/dt shows that the hearts treated with Iloprost preserved left ventricular function. Comparison of contractility indices between the groups revealed that contractile recovery was 59% in the control group and 71% in the Iloprost group (p < 0.05). Tumor necrosis factor (TNF) alpha level was significantly elevated in the control group (p < 0.001). Its level was 22.2 +/- 2.2 pg/mL in the control group and 13.8 +/- 1.0 pg/mL in the Iloprost group. E- and P-selectin levels were elevated in the control group (p < 0.001). ICAM-1 level was also elevated in the control group. ICAM-1 level was 17.7 +/- 1.8 ng/mL in the control group and 8.5 +/- 1.8 ng/mL in the Iloprost group. The Iloprost that was added to the cardioplegic solution and low dose administration during the pre- and post-ischemic period inhibits the toxic mediator release from endothelium-leukocyte interaction and reduces the severity of ischemia-reperfusion injury.

Spinal cord protection with the use of prostacyclin during aortic occlusion

This study was planned to investigate if prostacyclin (PGI2) would reduce spinal cord injury following aortic occlusion. Twelve dogs underwent 90 min of aortic occlusion. Six dogs received PGI2 and the remaining animals did not. PGI2 was administered at a dose of 25 ng/kg/min during occlusion of the aorta. There were five paraplegic animals in the control group and one in the PGI2 group 72 hr after aortic occlusion. Neurological recovery was better in the PGI2 group than in the control group (P < 0.05). Malondialdehyde level was 3.55 +/- 0.58 nmole/ml in the PGI2 group and 6.35 +/- 1.27 nmole/ml in the control group 60 min after aortic cross-clamp removal (P < 0.05). At the same time interval, protein thiol groups were 629 +/- 50 micromole/L in the PGI2 group and 376 +/- 69 micromole/L in the control group (P < 0.05). Distal arterial pressure and central venous pressure were 15 +/- 4 and 12 +/- 3 mm Hg in the control group and 33 +/- 5 and 7 +/- 1.6 mm Hg in the PGI2 group, respectively (P < 0.05). In this study exogenously administered PGI2 protected the spinal cord from the hazardous effects of aortic occlusion lasting 90 min.

Effect of in vitro hemolysis on 25 common biochemical tests

Clinical chemists frequently encounter hemolyzed samples. Our study examines the effects of hemolysis on the results of 25 common biochemical tests. We collected 60 15-mL blood samples from inpatients and outpatients and mechanically hemolyzed 10 mL of the samples in a two-step procedure. We classified serum from these samples as being nonhemolyzed, moderately hemolyzed, or severely hemolyzed and then performed 25 common biochemical tests. Statistical analysis of the results showed that hemolysis had the greatest effect on the lactate dehydrogenase, acid phosphatase, and potassium tests.

Changes in the serum levels of CK-MB, LDH, LDH1, SGOT and myoglobin due to cardiac surgery

Elevation of serum levels of enzymes due to myocardial necrosis is considered to be a specific finding for myocardial infarction. This study was designed to determine the changes in the levels of LDH, SGOT enzymes, LDH1, CK-MB isoenzymes and myoglobin in patients who have had coronary bypass grafting and who have had atriotomy for surgical correction without any evidence of myocardial infarction diagnosed by clinical, hemodynamic and electrocardiographic findings. It was found that CK-MB, LDH, LDH1 and myoglobin showed significant elevations which mimicked a perioperative myocardial infarction. SGOT also increased, but remained within the normal range. CK-MB, LDH and LDH1 increased more in the coronary bypass grafted patients whereas myoglobin increased in the patients who had atriotomies. It was concluded that in order to demonstrate a perioperative myocardial infarction it is necessary to determine at least two of these enzymes for a long period and to correlate these results with the clinical, hemodynamic and electrocardiographic findings.