Veno-arterial ECMO in severe acute right ventricular failure with pulmonary obstructive hemodynamic pattern

Extracorporeal membrane oxygenation (ECMO) is an effective rescue method for severe respiratory and cardiac failure. Right ventricular (RV) failure with cardiogenic shock is a critical condition with generally poor prognosis unless aggressive therapeutical measures are undertaken. Authors report on their initial experience with ECMO support in severe RV failure with cardiogenic shock caused by an obstructive hemodynamic pattern. Four patients with cardiogenic shock due to severe RV failure related to pulmonary arterial hypertension (2 patients), congenital heart disease with Eisenmenger physiology (1 subject) and massive pulmonary embolism (1 patient) were supported with emergency veno-arterial ECMO. ECMO circuit was instituted using peripheral cannulation in all subjects. Immediate hemodynamic and ventilatory improvement was observed in all patients. The mean support duration was 11 days (range 5-16 days), 2 (50%) patients were successfully weaned off ECMO and survived to hospital discharge. The other 2 patients were considered by mutual consensus to have irreversible organ damage, the ECMO support was withdrawn and the patients died. Bleeding complications were the main complications observed. As per initial experience, veno-arterial ECMO allows bypassing of the pulmonary bed, therefore, relieves the RV pressure overload and does not cause further elevation of the pulmonary pressures in contrary to RV assist devices. This aggressive management approach requires further clinical evaluation in order to establish its definite role in critical RV failure.

Presence of Borrelia burgdorferi in endomyocardial biopsies in patients with new-onset unexplained dilated cardiomyopathy

Dilated cardiomyopathy (DCM) represents the third most common cause of heart failure and the most frequent cause of heart transplantation. Infectious, mostly viral, and autoimmune mechanisms, together with genetic abnormalities, have been reported as three major causes of DCM. We hypothesized that Lyme disease (LD), caused by spirochete Borrelia burgdorferi (Bb), might be an important cause of new-onset unexplained DCM in patients living in a highly endemic area for LD such as the Czech Republic. We performed endomyocardial biopsy (EMB) in 39 consecutive patients presenting with symptomatic unexplained left ventricular (LV) systolic dysfunction lasting no more than 12 months. In eight subjects (21%), Bb was detected in the EMB sample by polymerase chain reaction or by electron microscopy. None of these patients exhibited any form of atrioventricular block or other extracardiac manifestation of Bb infection. Serological testing identified IgG antibodies against Bb in only two cases and IgM antibodies in none. All affected patients were treated with intravenous ceftriaxone for 3 weeks. At 6 months follow-up, LV morphology and function as well as functional status of these patients significantly improved. In conclusion, Bb infection may represent an important cause of new-onset unexplained DCM in patients living in endemic regions such as the Czech Republic. Because the antibiotic treatment appears to be markedly effective and serological examination does not provide a tool for diagnosing the disease, EMB focused on the detection of Bb should be performed in all patients from endemic areas with new-onset unexplained DCM not responding to conventional therapy.

Increase in plasma free haemoglobin during cardiopulmonary bypass in heart valve surgery: assessment of renal dysfunction by RIFLE classification

Heart valve surgery carries a high risk of renal insufficiency as an independent risk factor due to prolonged cardiopulmonary bypass. Multiple causes of cardiopulmonary bypass-associated renal damage have been described, and haemoglobin-induced renal injury is presently being investigated. Forty-three patients scheduled for heart valve surgery (mostly combined) were enrolled in the prospective study. Plasma free haemoglobin (PFH) levels were evaluated by photocolorimetric measurement at the start of procedures (t(0)) and before the end of extracorporeal circulation (t(1)). A statistically significant increase in PFH levels during cardiopulmonary bypass was detected [median values (interquartile range) - t(0): 62.0 (53.4) mg/L, t(1): 320.4 (352.2) mg/L], P < 0.001. A significant regression relationship between the duration of cardiopulmonary bypass and the increased PFH was found (Spearman's correlation coefficient 0.628, P < 0.001). In some elderly patients, the tendency towards a high release of PFH during cardiopulmonary bypass was more pronounced, but the overall association between age and PFH levels was of borderline significance (P = 0.077). The correlation between PFH and post-operative serum creatinine was low and non-significant, but the latter correlated highly with the pre-operative serum creatinine values (Spearman's correlation coefficient reached values of 0.6-0.7, P < 0.001). Patients were classified according to the Risk of renal failure, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage renal failure (RIFLE) classification for acute renal dysfunction during post-operative days 1 - 4; the influence of PFH levels at t(1) on the consequent RIFLE classification was not proven (P=0.648), but 4 patients in the Injury category had shown a higher median value of PFH (433.6 mg/L) in comparison with the others (29 patients with no acute renal dysfunction - 313.7 mg/L, 10 patients at Risk - 330.1 mg/L).

Intravascular ultrasound assessment of coronary artery involvement in Fabry disease

AIM

We used intravascular ultrasound (IVUS) to characterize coronary artery involvement in patients with Fabry disease (FD).

METHODS

Nine FD patients (5 women) were matched to 10 control patients (5 women) chosen from our IVUS database. Standard volumetric IVUS analyses were performed along with assessment of plaque echodensity.

RESULTS

Plaques in FD patients were diffuse and hypoechogenic compared with more focal and more echogenic lesions in control patients. Echogenicity of plaques was significantly lower in FD patients (median 30.7 +/- 12.9 vs 55.9 +/- 15.7, p = 0.0052, mean 37.2 +/- 15.6 vs 66.2 +/- 13.3, p = 0.0014). Diffusiveness was assessed as differences between mean and median plaque burden versus the plaque burden in each of the analysed cross-sections. These differences were lower in FD vs controls (5.8 +/- 4.8 vs 8.7 +/- 6.6, p < 0.001 for mean, and 5.8 +/- 4.9 vs 8.8 +/- 7.3, p < 0.001 for median) indicating a more diffuse involvement. The occurrence of lipid cores was significantly higher in FD patients than in controls (2.4 +/- 1.5 vs 1.0 +/- 0.94, p = 0.02).

CONCLUSION

IVUS showed diffuse hypoechogenic plaques in patients with FD. The explanation may be higher lipid content in plaques and accumulation of glycosphingolipid in smooth-muscle and endothelial cells.

Lack of association of iron metabolism and Dupuytren's disease

BACKGROUND

Iron accumulation as seen in genetic haemochromatosis is a major cause of hepatic fibrogenesis. A link between chronic liver disease and Dupuytren's disease (DD) is well established, especially in alcoholics.

AIM

The aim of the present study was to test the hypothesis that iron accumulation might cause fibrosis of the palmar aponeurosis leading to DD.

PATIENTS AND METHODS

We examined iron metabolism, mutations of the HFE gene, serum cholesterol, alcohol consumption, presence of chronic liver disease, diabetes and history of severe manual work in a group of 90 patients who had undergone surgery for a severe form of DD. The tissue removed during surgery was histologically examined to confirm the diagnosis of DD. For a control group, we used 33 healthy subjects with similar profiles.

RESULTS

The DD group consisted of 82 men and 8 women. Chronic liver disease was found in 27% of DD patients, compared with 6.1% of control subjects (P = 0.013). A history of hand traumatization was present in 33% of DD patients vs. 15% of control subjects (P = 0.048). Excessive alcohol consumption was present in 35.5% of DD patients compared with 15.1% of controls (P = 0.029). None of the other tested parameters, including the prevalence of HFE gene mutations, showed a significant difference between the two groups.

CONCLUSIONS

Iron accumulation does not play a major role in the pathogenesis of DD. However, sex, age, manual labour and alcohol consumption are risk factors for progression of DD. We observed a high incidence of chronic liver disease in patients with DD.

The ubiquitin ligase SCF(Grr1) is required for Gal2p degradation in the yeast Saccharomyces cerevisiae

F-box proteins represent the substrate-specificity determinants of the SCF ubiquitin ligase complex. We previously reported that the F-box protein Grr1p is one of the proteins involved in the transmission of glucose-generated signal for proteolysis of the galactose transporter Gal2p and fructose-1,6-bisphosphatase. In this study, we show that the other components of SCF(Grr1), including Skp1, Rbx1p, and the ubiquitin-conjugating enzyme Cdc34, are also necessary for glucose-induced Gal2p degradation. This suggests that transmission of the glucose signal involves an SCF(Grr1)-mediated ubiquitination step. However, almost superimposable ubiquitination patterns of Gal2p observed in wild-type and grr1Delta mutant cells imply that Gal2p is not the primary target of SCF(Grr1) ubiquitin ligase. In addition, we demonstrate here that glucose-induced Gal2p proteolysis is a cell-cycle-independent event.

[Primary biliary cirrhosis--specific anti-mitochondrial antibodies]

Primary biliary cirrhosis is a chronic liver disease, characterized by the destruction of the epithelial cells of the sublobular, interlobular and septal bile ducts and with the development of cirrhosis. The presence of anti-mitochondrial antibodies against the subunits of mitochondrial 2-oxoacids dehydrogenases is characteristic for patients with primary biliary cirrhosis. The aim of this work was to study the effect of anti-mitochondrial antibodies upon activity of the isolated mitochondrial pyruvate dehydrogenase complex after the incubation with serum from patients with primary biliary cirrhosis.

GROUP OF PATIENTS AND METHODS

The activity of the purified bovine pyruvate dehydrogenase complex was studied spectrophotometrically in presence of the serum (1: 1000) from five patients with primary biliary cirrhosis and from ten disease free controls.

RESULTS

The activity of the pyruvate dehydrogenase was decreased after incubation with the serum from patients with primary biliary cirrhosis. No similar inhibitory effect was found after incubation with serum from controls.

DISCUSSION

The inhibitory effect of the anti-mitochondrial antibodies upon activity of pyruvate dehydrogenase may broaden the spectrum of diagnostic methods in patients with primary biliary cirrhosis. Further investigations are necessary to assess the possible application of this method for monitoring of changes during the course of the disease and for assignation of the disease prognosis.

Glucose-induced monoubiquitination of the Saccharomyces cerevisiae galactose transporter is sufficient to signal its internalization

In Saccharomyces cerevisiae, the addition of glucose to cells growing on galactose induces internalization of the galactose transporter Gal2p and its subsequent proteolysis in the vacuole. Here we report that the essential step in Gal2p down-regulation is its ubiquitination through the Ubc1p-Ubc4p-Ubc5p triad of ubiquitin-conjugating enzymes and Npi1/Rsp5p ubiquitin-protein ligase. Moreover, Gal2p appears to be stabilized in mutant cells defective in the ubiquitin-hydrolase Npi2p/Doa4p, and the mutant phenotype can be reversed by overexpression of ubiquitin. An analysis of the fate of Gal2p in cells overexpressing wild-type ubiquitin as well as its variants incompetent to form polyubiquitin chains showed that monoubiquitination of Gal2p is sufficient to signal internalization of the protein into the endocytic pathway.

Virtual PCR

We present an algorithm that uses public sequence data to predict PCR products. The algorithm is implemented as a CGI script. Output is compared to real-world PCR.

AVAILABILITY

Perl code and instructions for installation are freely available over the internet at http://www.sci.muni.cz/LMFR/vpcr.html.

Optimisation of the quantitative determination of chlormequat by matrix-assisted laser desorption/ionisation mass spectrometry

The plant growth regulator chlormequat, an involatile quaternary ammonium salt, has been quantified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS). Restrictions for quantitative MALDI-TOFMS analysis, such as irreproducible crystallisation and unsatisfactory laser stability, have been overcome by the application of two synthesised isotopically labelled standards and the optimisation of the measurement protocol. Data acquisition at constant laser power was compared to data acquisition at approximately constant ion abundance of the relevant ions (analyte and internal standards). Data acquisition at constant ion abundance performed better and enabled a high number of consecutive firings to the same sample deposition area. Furthermore an increased sample-to-sample repeatability and a high reproducibility over several weeks without re-calibration have been attained by this method. Linearity over three orders of magnitude (0.05 to 30 ng/microL chlormequat), with a correlation coefficient of 0.9997, was achieved using [13C3]-chlormequat as internal standard. Limit of detection and limit of determination were determined to be in the low pg/microL range for pure standard solutions. Thin-layer chromatography was applied for the removal of high amounts of choline, which is often present in plant tissue extracts and can adversely affect the ionisation and detection of chlormequat by MALDI-TOFMS. The use of two internal standards ([13C3]- and [2H9]-chlormequat) enabled direct quantification and simultaneous control of the recovery.

Emergent management of the airway. New pharmacology and the control of comorbidities in cardiac disease, ischemia, and valvular heart disease

Once it is decided that the patient in distress requires tracheal intubation, the primary goal is to secure the airway as quickly and safely as possible to assure adequate oxygenation and ventilation. The clinician should quickly review the patient's history, physical examination findings, and laboratory data to determine the presence of cardiovascular disease, assess intravascular volume status, and formulate a plan for induction of anesthesia. The stresses of hypoxia, hypercarbia, acidosis, and extreme fatigue result in near-maximal sympathetic outflow that is manifest as tachycardia, labile blood pressure, and increased myocardial contractility. The astute clinician should anticipate that the tachycardia and hypertension associated with laryngoscopy and tracheal intubation is followed by a period of hypotension. This postintubation hypotension results from the acute marked attenuation of the sympathetic tone associated with resolution of hypoxia and hypercarbia, direct drug-induced negative inotropic effect, and vasodilation. The decrease in sympathetic vascular tone may result in hypotension by exacerbating the decrease in cardiac preload and afterload from hypovolemia. In addition, the use of positive pressure ventilation and positive end-expiratory pressure (PEEP) in these hypovolemic patients will further decrease ventricular preload by impeding venous return, leading to profound hypotension. Several pharmacologic agents are required to treat effectively the hemodynamic perturbations associated with induction, laryngoscopy, and tracheal intubation. Most sedative hypnotic agents that are administered for induction provide minimal to no analgesia. Patients are most often given a combination of drugs to provide adequate sedation, analgesia to blunt the noxious stimuli, and muscle relaxation to facilitate the laryngoscopy. The major challenge is to choose a combination of drugs that at the appropriate doses, effectively blunt the responses to intubation without contributing to postlaryngoscopy hypotension. One can use several strategies to accomplish these goals; administration of a narcotic analgesic before induction decreases the dose of induction agent and can attenuate the sympathetic response to intubation. Because of the prevalence of cardiovascular disease and hypovolemia in this population of patients, all chosen drugs should have minimal negative effect on cardiac function and patients with hypovolemia should be hydrated. Most clinical studies have been performed in hemodynamically stable patients, so the routine dosages of sedative hypnotics should be reduced substantially and titrated to effect. An additional strategy is to treat significant hemodynamic perturbations with vasopressors, vasodilators, short-acting selective beta-1 blockers, and inotropic agents. The choice of vasoactive agent depends on the magnitude of the hemodynamic response and the presence of specific underlying cardiovascular pathology.

Coronary angiography in Qatar: the first ten years

Cardiac catheterization in Qatar was initiated in July 1982. In ten years, a total of 3900 procedures were performed at Hamad General Hospital. Computerized data registry has been maintained since 1982. Isolated coronary angiography was done in 2911 patients; of these, 2635 (90.5%) were men, and 276 (9.5%) were women, the average age of the patients was 47+/-9.2 years (range, twenty-five to eighty-eight). Patients' nationality was Qatari in 492 (17%), and other Arabs in 610 (21%), and 1512 (52%) were from the Asian subcontinent. Myocardial infarction was the most common indication (43%). Single-vessel disease was found in 638 (22%), two-vessel disease in 630 (22%), three-vessel disease in 950 (33%), and nonsignificant coronary artery disease in 693 (24%) patients. Morbidity related to the coronary angiography was reported in 147 (5%) patients, but there was no mortality related to the procedure. In 822 (28%) patients, the age was forty years or younger. The angiographic findings of these younger patients were compared with those of the older ones. Younger patients were usually men of Asian subcontinental origin with a recent myocardial infarction (MI). Often, they had normal coronary arteries or single-vessel disease. Patients of Asian subcontinent origin were usually young male patients with a recent MI, who receive streptokinase, and have single-vessel disease.

The pharmacokinetics of lamivudine in patients with impaired hepatic function

OBJECTIVE

This study was designed to evaluate the effect of hepatic impairment on the pharmacokinetics of lamivudine.

METHODS

Sixteen patients not infected with hepatitis B virus or human immunodeficiency virus who had hepatic impairment due to liver cirrhosis were assigned to moderately or severely impaired groups by clinical signs/symptoms, 14C-aminopyrine metabolic activity and caffeine clearance and compared with eight healthy controls. Following a 300-mg dose of lamivudine, blood and urine samples were taken for drug assay.

RESULTS

Lamivudine was well tolerated in patients with hepatic impairment. There were no statistical differences in overall lamivudine exposure (in terms of AUC or Cmax) or other major pharmacokinetic parameters i.e. CLR, tmax and t1/2, between healthy control subjects and patients with moderate or severe hepatic impairment.

CONCLUSIONS

Hepatic impairment does not warrant dose modification of lamivudine based on this single-dose pharmacokinetic study.

Percutaneous transluminal coronary angioplasty experience in qatar: an analysis of more than 600 consecutive procedures

The present study describes the indications and results of 636 Percutaneous Transluminal Coronary Angioplasty (PTCA) procedures that were carried out in 596 patients. Of these, 366 (61.4 %) patients had Single Vessel Disease (SVD), 183 (30.7%) had Two Vessel Disease (2VD) and 47 (7.8%) had all Three Vessels Diseased (3VD). Dilatation of a single lesion was carried out in 564 (93.5%) patients. In another 41 (6.5%) patients, more than one vessel was dilated. The patients were predominantly male (562/596,93%) with a mean age of 46 (7.9 years. The indication for angiography was angina in 65.8% and for recent Acute Myocardial Infarction (AMI) in 34.2%. The number of procedures increased from 106 in 86-89 to 320 in 92-96 (an increase of 280%).

PTCA was carried out in the same session as the angiography in 113/596 (19%). In the remaining 81%, PTCA was planned as an elective procedure with a similar success rate (85% and 87% respectively, p=N.S). Females and Qatari patients had the highest success rates (97.6% and 90.5%) respectively.

The Left Anterior Descending (LAD) was the most frequently tackled vessel (53% of cases), Left Circumflex (LCX) in 20% and Right Coronary Artery (RCA) in 27%. For coronary stenoses, the overall success rate was 89%, being highest in the LAD (89.5%), lowest for LCX (82%) and moderate for RCA (88%). When faced with a total occlusion the overall success rate was 71% and was highest in RCA (84% success) and lowest in LCX (43%) and moderate in LAD (74%). Major complications were rare with only one mortality (1/596, 0.16%) and four emergency CABG is (4/596, 0.7%). Intracoronary stents were used as a bailout device in five patients and to obtain an optimal result in one patient. Stents were technically successful in all but one case.

Catabolite inactivation of the galactose transporter in the yeast Saccharomyces cerevisiae: ubiquitination, endocytosis, and degradation in the vacuole

When Saccharomyces cerevisiae cells growing on galactose are transferred onto glucose medium containing cycloheximide, an inhibitor of protein synthesis, a rapid reduction of Gal2p-mediated galactose uptake is observed. We show that glucose-induced inactivation of Gal2p is due to its degradation. Stabilization of Gal2p in pra1 mutant cells devoid of vacuolar proteinase activity is observed. Subcellular fractionation and indirect immunofluorescence showed that the Gal2 transporter accumulates in the vacuole of the mutant cells, directly demonstrating that its degradation requires vacuolar proteolysis. In contrast, Gal2p degradation is proteasome independent since its half-life is unaffected in pre1-1 pre2-2, cim3-1, and cim5-1 mutants defective in several subunits of the protease complex. In addition, vacuolar delivery of Gal2p was shown to be blocked in conditional end3 and end4 mutants at the nonpermissive temperature, indicating that delivery of Gal2p to the vacuole occurs via the endocytic pathway. Taken together, the results presented here demonstrate that glucose-induced proteolysis of Gal2p is dependent on endocytosis and vacuolar proteolysis and is independent of the functional proteasome. Moreover, we show that Gal2p is ubiquitinated under conditions of glucose-induced inactivation.