A subgroup of light-driven sodium pumps with an additional Schiff base counterion.

Light-driven sodium pumps (NaRs) are unique ion-transporting microbial rhodopsins. The major group of NaRs is characterized by an NDQ motif and has two aspartic acid residues in the central region essential for sodium transport. Here we identify a subgroup of the NDQ rhodopsins bearing an additional glutamic acid residue in the close vicinity to the retinal Schiff base. We thoroughly characterize a member of this subgroup, namely the protein ErNaR from Erythrobacter sp. HL-111 and show that the additional glutamic acid results in almost complete loss of pH sensitivity for sodium-pumping activity, which is in contrast to previously studied NaRs. ErNaR is capable of transporting sodium efficiently even at acidic pH levels. X-ray crystallography and single particle cryo-electron microscopy reveal that the additional glutamic acid residue mediates the connection between the other two Schiff base counterions and strongly interacts with the aspartic acid of the characteristic NDQ motif. Hence, it reduces its pKa. Our findings shed light on a subgroup of NaRs and might serve as a basis for their rational optimization for optogenetics.

Cardiac rupture in embolic myocardial infarction after implantation of a valved aortic conduit.

We report a case of an apical myocardial infarction complicated by left ventricular wall rupture due to coronary artery embolism four years after surgery of an acute type A dissection of an aortic aneurysm with implantation of a valved aortic conduit.

Influence of cardiopulmonary resuscitation on levels of tumour markers.

Tumour markers (TM), including alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), cancer antigen (CA) 15-3 and prostate-specific antigen (PSA), are serum markers for malignant diseases. Previous studies investigating the effect of acute and chronic inflammation, cardiopulmonary bypass surgery and cardiopulmonary resuscitation (CPR) on levels of TM showed conflicting results. Cardiopulmonary resuscitation (CPR) may result in a profound inflammatory response, and is frequently associated with severe tissue hypoperfusion. The present study investigated whether AFP, CEA, CA 15-3 and PSA are influenced by CPR. Alpha-fetoprotein (AFP), CEA, CA 15-3 and PSA (only in male patients) were assessed immediately after hospital admission, 6 h, 12 h and 2 days after prolonged CPR in eight male and 12 female patients. Serum levels of AFP, CEA, CA 15-3 did not change significantly after CPR. Prostate-specific antigen (PSA) levels increased significantly with a highest level in the study period 48 h after CPR (3.3 +/- 3.1 and 28.3 +/- 30.5 ng/mL for baseline and 48 h levels, respectively; P < 0.001). Alpha-fetoprotein (AFP), CEA, CA 15-3 and PSA (in men) values above the normal range were observed in 0%, 13.8%, 3.8% and 46.9% of all measurements respectively. At least one value above the normal range were observed in 0%, 20%, 5% and 75% of all patients for AFP, CEA, CA 15-3 and PSA (in men) respectively. Baseline values of AFP, CEA, CA 15-3 and PSA (in men) were above the normal range in 0%, 15%, 5% and 10% of all patients respectively. Levels for all markers did not differ significantly between survivors and non-survivors. In conclusion, prolonged CPR does not influence AFP, CEA, CA 15-3 serum levels, but is frequently associated with increases of PSA. Thus, in contrast to PSA, interpretation of AFP, CEA, CA 15-3 serum levels is not influenced by recent CPR.

Chronic total occlusion--a definite state?

Successful recanalisation of a chronic coronary occlusion may result in survival advantage. This report describes a 61-year-old man with an initially chronic occluded right coronary artery. A follow-up angiography 2 years later revealed a spontaneous recanalisation.

Catecholamine therapy inducing dynamic left ventricular outflow tract obstruction.

Hypertrophic obstructive cardiomyopathy with significant hypertrophy of the basal septum is the most frequently reported cause of left ventricular outflow tract (LVOT) obstruction. Additionally, other conditions such as dehydration, sepsis, vasodilatation, or mitral valve repair have been associated with LVOT obstruction. In this report, we present a case of a patient without hypertrophy who developed severe dynamic left ventricular outflow tract obstruction during catecholamine stimulation for shock that complicated severe pancreatitis. The present case serves as a reminder that hypovolemia together with a hyperdynamic state resulting from catecholamine administration may result in the development of dynamic LVOT obstruction even if baseline cardiac evaluation is unremarkable. Early detection and intensive efforts to reverse the underlying conditions, including cessation of catecholamine therapy and correction of hypovolemia are essential.

Obesity, body fat and coronary atherosclerosis.

BACKGROUND: Recent prospective studies have provided compelling evidence that obesity is a risk factor for the occurrence of clinical coronary events. However, the link between angiographically determined coronary atherosclerosis and obesity still remains controversial. We conducted this cross-sectional study in a clinical setting to investigate the relation of the obesity and body fat (BF) with angiographically defined coronary atherosclerosis. PATIENTS AND METHODS: Six hundred and seventy-three men (median age 64 years) and four hundred and twenty-eight women (median age 69 years) who underwent coronary angiography for suspected or known coronary heart disease were analyzed. The body mass index (BMI) and the BF were used as main exposure variables, and either the presence of significant (> or =50%) coronary diameter stenosis or a coronary artery disease severity score were defined as outcome variables, in a sex-specific logistic regression analysis. RESULTS: Among male patients, BF was slightly higher with increasing number of vessels involved (adjusted P for trend <0.05). In contrast, BMI showed no association with presence and severity of coronary artery disease (CAD). The odds ratios (ORs) for the presence of significant stenosis across quartiles of BMI were 1.0 (reference), 0.9, 1.1 and 0.7 (adjusted P for trend 0.61). This result did not differ between younger and older men. Among females, however, both BF and BMI were not significantly associated with an increasing number of vessels involved. CONCLUSION: These results suggested that BF may be predictive of an increasing number of coronary vessels involved among male patients, but not among female patients. This study failed to detect a positive association of presence and severity of CAD with BMI.

Postoperative atrial fibrillation independently predicts prolongation of hospital stay after cardiac surgery.

AIM: Postoperative atrial fibrillation (AF) occurs in up to 50% of cardiac surgery patients and represents the most common postoperative arrhythmic complication. A reduction of the length of hospital stay is a desirable goal in preventive strategies of postoperative AF. The aim of the present investigation was to determine whether prolonged postoperative hospital stay associated with AF after cardiac surgery surgery is attributable to the arrhythmia itself or to baseline characteristics of patients who develop AF. METHODS: Patients undergoing elective cardiac surgery in the absence of heart failure and significant left ventricular dysfunction (n = 253; average age 65+/-11 years) were recruited to the present prospective study. Midline sternotomy procedures with standard surgical techniques for normothermic cardiopulmonary bypass in coronary artery bypass grafting and valvular surgery were used. RESULTS: A total of 99 patients (39.1%) of the study population developed AF during the postoperative period. AF patients were older and more likely to have surgery for valvular heart disease and less likely to have antiarrhythmic drugs including beta-adrenergic blockers than patients without AF, but both patients with and without AF had similar body mass index and duration of surgery. Postoperative hospital stays were longer in patients with AF compared to those without AF (14.9+/-5.7 vs 10.6+/-3.6, respectively; P = 0.001). Multivariate analysis, adjusted for age and postoperative complications, demonstrated that postoperative hospital stay was 14.2+/-5.3 days in patients with AF and 10.8+/-3.8 days in patients without AF (P < 0.01). Treatment with oral antiarrhythmic drugs that reduce AF is associated with a reduction of postoperative hospital stay. CONCLUSIONS: Despite baseline characteristics differed between patients with and without postoperative AF, most of the prolongation of hospital stay can be attributed to the rhythm disturbance itself.

Antiarrhythmic therapy on prevention of postoperative atrial fibrillation in patients after heart surgery.

The incidence of supraventricular arrhythmias is high following open-heart surgery, occurring in 25% to about 50% of patients. The most common of these arrhythmias is atrial fibrillation (AF). Postoperative AF has been associated with increased incidence of other complications and increased hospital length of stay. Atrial arrhythmias are most frequent in the first two to three days after cardiothoracic surgery, but they can occur at any point in the recovery period. Age and concomitant valular heart disease are consistently the independent factors most strongly associated with postoperative atrial fibrillation. Prevention of AF seems to be a reasonable clinical goal, and, consequently, many randomized trials have evaluated the effectiveness of pharmacological and nonpharmacological interventions for prevention of AF. The main indication for AF prophylaxis remains the shorteningof length of hospital stay and possibly reduction in stroke. The optimal treatment strategies for reducing postoperative AF are not well established. Commonly used therapeutic approaches include the use of rate-controlling drugs such as beta-blockers, calcium antagonists, and digoxin. Some pharmacological strategies including beta-blockers, sotalol, and amiodarone have shown to reduce risk of postoperative AF and may reduce length of hospital stay. There is no convincing evidence that reducing postoperative AF reduces stroke. This review summarizes current evidence from randomized controlled trials to estimate the effect of pharmacological and non pharmacologic interventions on the occurrence of AF after open-heart surgery and its effects on postoperative outcome.

Spontaneous coronary artery dissection involving the left main stem: assessment by intravascular ultrasound.

This case report describes the devastating consequences of spontaneous coronary dissection in a 36 year old female patient who otherwise had a normal coronary arteriogram. Intravascular ultrasound showed coronary artery dissection and intramural haematoma at the left main stem coronary artery. Acute coronary syndrome developed and subsequently surgical revascularisation was performed successfully.

Effective control of hypertension: a project of the Hungarian Society of Hypertension, baseline data.

The aim of the project is to assess the quality and improve the preventive and curative practices at the primary care level in Hungary. A total of 50 general practitionaires were selected on a voluntary basis in Budapest, Hungary, and from them, 30 were randomized to the intervention (I) group and 20 to the reference (R) group. The members in the I group have been trained for the official hypertension guideline and their everyday work is monitored. Those in the R group have only been monitored to measure the efficacy of the training. In all, 10% from the known hypertensive persons (N=10,799) and 5% of the remaining (nonhypertensive) patients (N=60,341) were selected randomly from the GP's computer files and invited for screening investigation performed by trained medical students. They measured the blood pressure of patients, assessed the cardiovascular risk status and the quality of education of patients by standardized questionnaires. In total, 4083 patients were invited, but only 39.2% attended the screening visit. The prevalence of undetected hypertension was 34.6%. This prevalence was significantly higher in the older (>60 years: 46.8%) than in the younger (<50 years: 20.8%, P<0.0001) age group and it was higher in men (41.5%) than in women (30.1%, P<0.001). The proportion of H patients on drug treatment was 85.3% and the frequency of patients under effective blood pressure control (eg<140/90 mmHg) was 27.8%. Counselling to patients for a healthier lifestyle (exercise, smoking, alcohol consumption, diet) was very rare. In conclusion, our data represent the primary care of Budapest and may not be relevant to the whole country. As a consequence of this study, education of primary care physicians and patients is a must for further improvement of hypertension care.

An insulin-like growth factor-mediated, phosphatidylinositol 3' kinase-independent survival signaling pathway in beta tumor cells.

Hyperproliferation of tumor cells usually coincides with increased tumor cell apoptosis. To overcome apoptosis, tumor cells frequently induce the expression of growth factors that mediate cell survival. In nontransformed cells, including fibroblasts and neurons, survival factor-mediated signal transduction involves the activation of phosphatidylinositol 3' kinase (PI-3K) and protein kinase B/c-Akt (PKB). Here we demonstrate that tumor cell lines derived from a transgenic mouse model of pancreatic beta cell carcinogenesis use insulin-like growth factors to repress apoptosis independently of PI-3K and PKB. The results indicate that tumor cells can use additional survival signal transduction pathways.

Divalent cations and the electrostatic potential around DNA: Monte Carlo and Poisson-Boltzmann calculations.

The predictions of counterion condensation theory for divalent ions were tested by comparison with the results of Monte Carlo calculations on an all-atom model of DNA. Monovalent-divalent competition at the polyelectrolyte surface was investigated by varying the partial molar volume of divalent ions. To assess the viability of using Poisson-Boltzmann (PB) calculations for determining divalent ion concentrations at DNA surfaces, Monte Carlo (MC) calculations were compared with PB calculations using different models of the dielectric continuum. It was determined that, while standard PB calculations of divalent ion surface densities are about 25-30% below those predicted by MC techniques, and somewhat larger than errors previously determined for monovalent ions, errors due to the use of the mean-field approximation of PB theory are smaller than those arising from common assumptions regarding the dielectric continuum.

Impairment of survival factor function potentiates chemotherapy-induced apoptosis in tumor cells.

The balance between tumor cell proliferation and apoptosis is a critical determinant of malignant tumor outgrowth. In a transgenic mouse model of beta cell tumorigenesis (Rip1Tag2), insulin-like growth factor II (IGF-II) is up-regulated during the onset of tumor cell proliferation. Disruption of IGF-II expression in these transgenic mice causes a dramatic increase of beta tumor cell (betaTC) apoptosis, indicating that IGF-II acts as a survival factor. Here we report that beta tumor cell lines derived from IGF-II-deficient Rip1Tag2 mice show a higher incidence of apoptosis than their wild-type counterparts. In particular, IGF-II-deficient betaTCs are more sensitive to apoptotic stimuli, such as serum deprivation and staurosporine, and to chemotherapeutic agents, such as daunomycin, etoposide, or vincristine. Thus, the lack of the survival factor IGF-II potentiates chemotherapeutic treatment of betaTCs. Furthermore, normal betaTCs can be sensitized to chemotherapy when transfected with a dominant-negative mutant of the IGF-I receptor. These results demonstrate a pivotal role for IGF-mediated signaling in the survival of tumor cells and, thus, raise the possibility of novel approaches toward cancer therapy by interfering with survival factor function.

Differentiated nursing practice: assessing the state-of-the-science.

The authors present their findings following an exhaustive literature review of research on differentiated nursing practice (DNP) that used a number of tools to measure various aspects of DNP that are applicable across the health care delivery continuum. Issues related to DNP include: optimal nursing care, matching patient needs with nurse competencies, effective use of nursing resources, equitable compensation, career satisfaction, loyalty to employers, and enhanced prestige of the nursing profession. One 1992 Massachusetts study of a three-role oncology unit project (including patient care manager, clinical nurse, and patient care technician), showed positive change in five criteria including: standards of nursing care, actual care hours, average labor costs, job satisfaction and patient satisfaction. A 1990 Arizona study that included unit assistants concluded that DNP supported a decline in the use of supplemental staff and staff overtime which led to cost savings, and increases in the actual hours of care and nurse satisfaction.

Polyethylenimine (PEI) is a simple, inexpensive and effective reagent for condensing and linking plasmid DNA to adenovirus for gene delivery.

A simple and inexpensive method of condensing and linking plasmid DNA to carrier adenovirus particles is described. The synthetic polycation polyethylenimine is used to condense plasmid DNA into positively charged 100 nm complexes. These PEI-DNA complexes are then bound to adenovirus particles through charge interactions with negative domains on the viral hexon. The resulting transfection complexes deliver plasmid DNA to cells by the adenovirus infectious route without interference from virus gene expression because psoralen-inactivated virus is employed. The PEI-DNA-adenovirus complexes display DNA delivery comparable to more sophisticated DNA virus complexes employing streptavidin/biotin linkage, but require no special reagents and are much easier to prepare.

A rapid, quantitative and inexpensive method for detecting apoptosis by flow cytometry in transiently transfected cells.

We describe a rapid and quantitative flow cytometric method for determining the apoptotic or anti-apoptotic potential of a gene in various cell types. A plasmid carrying green fluorescent protein (GFP) is co-transfected with an expression vector encoding the gene of interest. Subsequently cells are stained with propidium iodide and, utilising flow cytometry, transfected, GFP-expressing single cells are detected and apoptotic cells in this population are identified by their DNA content of <2 N. The method detects apoptosis as reliably as established methods using in situ nick-end labelling but is faster, easier and less expensive.

p72: a human nuclear DEAD box protein highly related to p68.

P72, a novel human member of the DEAD box family of putative RNA-dependent ATPases and ATP-dependent RNA helicases was isolated from a HeLa cDNA library. The predicted amino acid sequence of p72 is highly homologous to that of the prototypic DEAD box protein p68. In addition to the conserved core domains characteristic of DEAD box proteins, p72 contains several N-terminal RGG RNA-binding domains and a serine/glycine rich C-terminus likely involved in mediating protein-protein interactions. A p72-specific probe detects two mRNAs of approximately 5300 and 9300 bases which, although ubiquitously expressed, show variability in their expression levels in different tissues. Purified recombinant p72 exhibits ATPase activity in the presence of a range of RNA moieties. Immunocytochemical studies of p68 and p72 show that these proteins localise to similar locations in the nucleus of HeLa cells, suggesting their involvement in a nuclear process.

Monte Carlo and Poisson-Boltzmann calculations of the fraction of counterions bound to DNA.

The counterion density and the condensation region around DNA have been examined as functions of both ion size and added-salt concentration using Metropolis Monte Carlo (MC) and Poisson-Boltzmann (PB) methods. Two different definitions of the "bound" and "free" components of the electrolyte ion atmosphere were used to compare these approaches. First, calculation of the ion density in different spatial regions around the polyelectrolyte molecule indicates, in agreement with previous work, that the PB equation does not predict an invariance of the surface concentration of counterions as electrolyte is added to the system. Further, the PB equation underestimates the counterion concentration at the DNA surface, compared to the MC results, the difference being greatest in the grooves, where ionic concentrations are highest. If counterions within a fixed radius of the helical axis are considered to be bound, then the fraction of polyelectrolyte charge neutralized by counterions would be predicted to increase as the bulk electrolyte concentration increases. A second categorization--one in which monovalent cations in regions where the average electrostatic potential is less than -kT are considered to be bound--provides an informative basis for comparison of MC and PB with each other and with counterion-condensation theory. By this criterion, PB calculations on the B form of DNA indicate that the amount of bound counterion charge per phosphate group is about .67 and is independent of salt concentration. A particularly provocative observation is that when this binding criterion is used, MC calculations quantitatively reproduce the bound fraction predicted by counterion-condensation theory for all-atom models of B-DNA and A-DNA as well as for charged cylinders of varying linear charge densities. For example, for B-DNA and A-DNA, the fractions of phosphate groups neutralized by 2 A hard sphere counterions are 0.768 and .817, respectively. For theoretical studies, the radius enclosing the region in which the electrostatic potential is calculated to be less than -kT is advocated as a more suitable binding or condensation radius than that enclosing the fraction of counterions given by (1 - epsilon-1). A comparison of radii calculated using both of these definitions is presented.

The effect of a variable dielectric coefficient and finite ion size on Poisson-Boltzmann calculations of DNA-electrolyte systems.

The results of variable dielectric coefficient Poisson-Boltzmann calculations of the counter-ion concentration in the vicinity of an all-atom model of the B-form of DNA are presented with an emphasis on the importance of spatial variations in the dielectric properties of the solvent, particularly at the macro-ion-solvent interface. Calculations of the distribution of hard-sphere electrolyte ions of various dimensions are reported. The presence of a dielectric boundary significantly increases the magnitude of the electrostatic potential with a concomitant increase in the accumulation of small counter-ions in the groove regions of DNA. Because ions with radii greater than 2 A have restricted access to the minor groove, the effect there is less significant than it is within the major groove. Changes in the dielectric coefficient for the electrolyte solution, allowing variation from 10 to 25, 40, 60, and 78.5 within the first 7.4 A of the surface of DNA, substantially increases the calculated surface concentration of counter-ions of all sizes. A lower dielectric coefficient near the macro-ion surface also tends to increase the counter-ion density in regions where the electrostatic potential is more negative than -kT. Regardless of the choice of dielectric coefficient, the number of ions in regions where the electrostatic potential is less than -kT remains the same for 0.153 M added 1-1 monovalent electrolyte as for the case without added salt. The strong dependence of the calculated distribution of counter-ion density on the choice of dielectric coefficients representing the solvent continuum suggests that care must be taken to properly characterize the physical system when studying electrostatic properties using these methods.