[Diagnostic and Prognostic Possibilities of the Redox-Potential Electrochemical Measurements in Blood Plasma].

AIMS: Determination of operating characteristics of the test based on blood plasma redox potential monitoring in patients with different patho- logical conditions associated with impaired oxygen metabolism during treatment in postoperative period and expanding the range of parameters of the developed method of investigation of blood plasma redox potential. METHODS: It were examined healthy volunteers group as following group (n = 63), groups of patients with transplanted liver (n = 64), kidney (n = 59), and lungs (n = 7). Redox potential measurements were done by platinum electrode, reference electrode was silver-chlorine one. Potentiostate IPC-ProL was used to registrate and record a dependence redox potential via time. Time of measurement was 15 min. RESULTS: statistically significant differencees of redox potentials ranges was found in healthy volunteers and patients with transplanted kidney and liver. Ratio of measured redox potentials coincident with the values within the confidence interval in healthy volunteers was 12% in patients with transplanted kidney and 10% in patients with transplanted liver. We observed significant differences in the nature of changes of blood plasma's redox potential values in course of monitoring of subgroups of patients with and without complications after liver transplantation. It was found that sensitivity of electrochemical method was 85%, selectivity--69.8%, precision--85.2%. CONCLUSION: we discovered value ranges of blood plasma redox potential typicalfor different pathological states; we detected an interaction between the effect of treatment and quantitative changes in the values of the blood plasma redox potentials; criterion for early predicition of complications in patients with transplanted liver was proposed basing on redox potential monitoring during postoperative period.

GABAergic hub neurons orchestrate synchrony in developing hippocampal networks.

Brain function operates through the coordinated activation of neuronal assemblies. Graph theory predicts that scale-free topologies, which include "hubs" (superconnected nodes), are an effective design to orchestrate synchronization. Whether hubs are present in neuronal assemblies and coordinate network activity remains unknown. Using network dynamics imaging, online reconstruction of functional connectivity, and targeted whole-cell recordings in rats and mice, we found that developing hippocampal networks follow a scale-free topology, and we demonstrated the existence of functional hubs. Perturbation of a single hub influenced the entire network dynamics. Morphophysiological analysis revealed that hub cells are a subpopulation of gamma-aminobutyric acid-releasing (GABAergic) interneurons possessing widespread axonal arborizations. These findings establish a central role for GABAergic interneurons in shaping developing networks and help provide a conceptual framework for studying neuronal synchrony.

Functional plasticity triggers formation and pruning of dendritic spines in cultured hippocampal networks.

Despite widespread interest in dendritic spines, little is known about the mechanisms responsible for spine formation, retraction, or stabilization. We have now found that a brief exposure of cultured hippocampal neurons to a conditioning medium that favors activation of the NMDA receptor produces long-term modification of their spontaneous network activity. The conditioning protocol enhances correlated activity of neurons in the culture, in a process requiring an increase in [Ca(2+)](i) and is associated with both formation of novel dendritic spines and pruning of others. The novel spines are likely to be touched by a presynaptic terminal, labeled with FM4-64 dye, whereas the absence of such terminals increases the likelihood of spine pruning. These results indicate that long-term functional changes are correlated with morphological modifications of dendritic spines of neurons in a network.

Regulation of rat brain vesicular monoamine transporter by chronic treatment with ovarian hormones.

Ovarian steroids play an important role in neuroregulation and in the pathophysiology of various neuropsychiatric disorders. Most of the studies focused on the impact of gonadal steroids on post-synaptic receptors and plasma membrane transporters. In the present study, we evaluated the effect of chronic treatment with ovarian steroids on the expression of rat brain vesicular monoamine transporter (VMAT2). Ovariectomized rats were treated for 21 days with estradiol, progesterone or both. VMAT2 gene expression was assessed on the protein level by high affinity [3H]dihydrotetrabenazine ([3H]TBZOH) binding using autoradiography and on the mRNA level by in situ hybridization. Progesterone administration led to a decrease in [3H]TBZOH binding in the middle striatum and in the nucleus accumbens and to a parallel decrease in VMAT2 mRNA level in the substantia nigra pars compacta and dorsal raphè nuclei. Chronic estradiol treatment reduced VMAT2 mRNA level in the dorsal raphè and [3H]TBZOH binding in middle part of the striatum and nucleus accumbens but did not affect VMAT2 mRNA level in the substantia nigra pars compacta. Simultaneous administration of both ovarian steroids did not modulate VMAT2 mRNA in the substantia nigra pars compacta as well as [3H]TBZOH binding in the striatum or the nucleus accumbens but reduced VMAT2 mRNA level in the dorsal raphè. It appears that ovarian steroids may play a crucial role in the regulation of VMAT2 gene expression in the dopamine and serotonin systems. This modulatory activity may be relevant to synaptic and neuronal plasticity as well as to the molecular and cellular pathophysiology of gender-specific neuropsychiatric disorders.

Surgical management of radiation-induced heart disease.

BACKGROUND: With the increasing population of patients with prior mediastinal irradiation, cardiac surgeons will encounter patients with radiation-induced damage to the heart and the great vessels. Awareness of the pathology and the surgical management is essential to provide optimal care for these patients. METHODS: Eight patients with radiation-induced heart disease were encountered in the last 10 years. After a brief clinical presentation, the surgical management of radiation-induced heart disease is reviewed. RESULTS: Radiation can affect all the structures in the heart, including the coronary arteries, the valves, and the conduction system. The pericardium is the most commonly involved, and the conduction system is the least involved. Pericardiectomy is quite effective in patients with symptomatic pericardial effusion or constriction. The coronary lesions are located predominantly in the ostial or proximal regions of the epicardial vessels. Percutaneous transluminal coronary angioplasty alone appears to have a high rate of restenosis. Surgical revascularization has good long-term results, and the internal mammary artery should be used if it is satisfactory. The aortic and mitral valves are more commonly involved than the tricuspid and pulmonary valves. Myocardial dysfunction predominantly affects the right ventricle and requires particular attention during cardiopulmonary bypass and in the postoperative period. Restoration of sinus rhythm is essential in view of stiffness of the ventricles. Flexibility in the surgical approach with selective use of thoracotomy will facilitate the surgical procedure in certain patients. CONCLUSIONS: Surgeons should be well versed in all the manifestations and the management of radiation-induced heart disease.

Saccular outpouchings of an ascending aortic aneurysm: transesophageal echocardiographic appearance.

The differential diagnosis of cavities in the ascending aorta includes pseudoaneurysms, intimal flaps, and abscesses. We describe the transesophageal echocardiographic and pathologic appearance of a fusiform ascending aortic aneurysm that contained atypical outpouchings that were initially confused with an intimal flap. Awareness of this unreported abnormality and its echocardiographic features will avoid the misdiagnosis of more serious aortic pathology such as acute aortic dissection or infective endocarditis.

Selectivity in aortic root reconstruction.

Anatomical variations in aortic root pathology, including combinations of dissection, aneurysmal dilatation, annuloaortic ectasia, and valve disease, defy standardized repair and mandate application of various surgical reconstructions. To examine these techniques, and their influence on morbidity and mortality, we reviewed 53 consecutive patients undergoing aortic root procedures. Thirty-two patients underwent total root reconstruction. Of these, 21 underwent Bentall procedures, 9 had a modification thereof, and 2 underwent a Cabrol reconstruction. Less extensive pathology was corrected in 21 patients with a partial root reconstruction. These included aortic valve replacement (AVR) and a separate tube graft in 14 patients, AVR and primary aortic repair +/- wrapping in 4 individuals, and AVR and patch aortic root enlargement in 3 patients. Mean age was 53.2 years (range 20 to 79). Nearly 20% had undergone previous cardiac surgery and 7.5% were emergencies. Early mortality was 4%. Complications included dysrhythmias (48%), myocardial infarction (4%), stroke (4%), pneumonia (14%), and pancreatitis (2%). There were no reoperations for bleeding. Three late complications, one pseudoaneurysm and two perivalvular leaks, were successfully repaired. Late deaths (13.7%) were caused by congestive heart failure (3), myocardial infarction (MI) (1), cancer (1), stroke (1), and accidental fall (1). Kaplan-Meier analysis reveals 1-, 5-, and 10-year survivals of 98%, 81%, and 66%. Survival and mortality data did not differ between groups, and except for the incidence of atrial dysrhythmias, complication rates also were not significantly different. This series illustrates the need for and the successful application of a selective approach to aortic root reconstruction.

Atrial natriuretic peptide release in response to different positive end-expiratory pressure levels.

OBJECTIVE: To assess the influence of different positive end-expiratory pressure (PEEP) levels on plasma atrial natriuretic peptide concentrations. DESIGN: Prospective, randomized study. SETTING: Intensive care unit of a university hospital. PATIENTS: Twenty-seven patients who were mechanically ventilated due to acute respiratory failure. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: The patients were randomized into three groups: in each group, a defined PEEP level (5, 10, or 15 cm H2O, respectively) was applied, alternating with zero PEEP (0 cm H2O) in consecutive order (reversal experiment). Blood samples for the determination of atrial natriuretic peptide concentrations were drawn from the pulmonary artery and the radial artery catheters. There were no decreases in atrial natriuretic peptide concentrations with a PEEP of 5 cm H2O, but significant decreases could be shown for PEEP values of 10 and 15 cm H2O. The patients of all groups were subjected to PEEP levels of 5, 10, 15, and 20 cm H2O in randomized order (step experiment). The data demonstrated a significant inverse correlation between changes in PEEP levels and changes in plasma atrial natriuretic peptide concentrations. CONCLUSION: The data suggest that the release of atrial natriuretic peptide is influenced by a PEEP of > or = 10 cm H2O, while a PEEP of < or = 5 cm H2O does not disturb this cardiac endocrine function.

Automatic implantable cardioverter defibrillator: surgical approaches for implantation.

Surgical approaches for implantation of the automatic cardioverter defibrillator are sternotomy, left thoracotomy, subxiphoid, and subcostal. Although any one of these may be combined with insertion of one or more of the electrodes transvenously, surgical entry into the chest is required for every noninvestigational defibrillator implantation operation. The approaches differ in exposure provided for selecting electrode sites and for handling untoward events, in amount and location of tissue that must be divided or dissected, and in average time required. The operation is an electrical one. Its purpose is to obtain reliable rhythm sensing so that defibrillation or cardioversion shocks will occur only when necessary, and to obtain low enough defibrillation thresholds for shocks of 30 joules or less to have a 10-joule defibrillation safety margin. Many of the patients have had previous cardiac operations. They usually have low or very low ejection fractions. Intraoperative electrophysiological testing with often multiple defibrillation episodes is required. The choice of approach varies with the state of the patient, the institutional experience, and the surgeon. This article describes technique, and the advantages and disadvantages of the four approaches as used by four surgeons in four different institutions.

The use of fibrin sealant for embryo transfer: development and clinical studies.

Many embryo transfers after in-vitro fertilization may fail because of expulsion of the embryos from the uterus. Approximately 5-8% of pregnancies resulting from embryo transfer are ectopic. The aim of our study was to find a technique to avoid ectopic pregnancies and to improve the pregnancy rate. We used a two-component fibrin sealant which also contains a fibrinolysis inhibitor (aprotinin) at various concentrations. After gaining experience with mouse embryos, the sealant was used in human embryo transfer with great success. The results of a pilot study encouraged us to perform a prospective randomized study on 546 patients (270 with fibrin sealant, 276 conventional embryo transfers). There were 47 (17.0%) orthotopic pregnancies and 6 (2.2%) ectopic pregnancies in the control group, whereas there were 51 (18.9%) intrauterine and no ectopic pregnancies in the treatment group. The difference in ectopic pregnancies was statistically significant (P less than 0.05). With regard to the aprotinin concentration, there was a trend towards better results with 100-150 kIU (28.5% clinical pregnancies) in comparison to 250-300 kIU (19.2%) or no aprotinin (20.4%) (not significant). Further improvements of the technique may raise the pregnancy rate when fibrin sealant is used. As shown in our prospective randomized study, ectopic pregnancies may be completely avoided.

Airway management in a case of neck impalement: use of the oesophageal tracheal combitube airway.

A patient presented with neck impalement after a traffic accident. Respiratory arrest demanded immediate tracheal intubation, which was impossible as a wooden splinter had partially obstructed the pharynx and prevented laryngoscopy. An oesophageal tracheal Combitube airway was inserted successfully and the patient's lungs were ventilated adequately until tracheotomy was performed.

Inferior vena cava interruption with the Hunter-Sessions balloon: eighteen years' experience in 191 cases.

Over a period of 18 years, 191 consecutive patients had interruption of the inferior vena cava with the Hunter-Sessions balloon for complications of deep venous thrombosis and pulmonary embolism. Causes of deep venous thrombosis and pulmonary embolism included the postoperative state (33%), cancer (32%), and stroke (11%). There were 93 females and 98 males; ages ranged from 17 to 90 years (average, 57 years). Indications for placement of the Hunter-Sessions balloon were as follows: contraindication to anticoagulants (33%), anticoagulant complications (24%), pulmonary embolism despite anticoagulants (45%), and others including inferior vena cava thrombus (12%). Sixty-eight percent had clinical phlebitis and 36% had positive venography results. Pulmonary embolism had occurred in 165 patients (86%). It was diagnosed by ventilation-perfusion scanning (75%), angiography (23%), or on clinical grounds (2%) in patients with confirmed deep venous thrombosis. At the time of the procedure 52% were in significant cardiopulmonary distress, and 10% were intubated and on respirators. Transjugular placement was done in 188 patients, and transfemoral placement was performed in three. All All tolerated inferior vena cava interruption. Thirty patients (15%) died while in the hospital an average of 21 days after balloon placement, which was unrelated to the deaths. Follow-up was 45 months. Ninety-four patients are dead, 95 are alive, and the status of two patients is unknown. Twenty-nine of 64 patients (45%) who died after they left the hospital died of cancer. At last follow-up, 75% of patients had legs free of edema and 25% had need for elastic stockings. No malfunction or migration has occurred with the device. No patient had a pulmonary embolism while in the hospital after insertion of the Hunter-Sessions balloon, and no patient died of pulmonary embolism. Late minor pulmonary embolism occurred in three patients.

Patient assessment of care in a pain management unit.

Seventy individuals, 40 females and 30 males with a mean age of 58.5, suffering from protracted pain and associated incapacitation (due, mainly, to rheumatoid or osteoarthrotic conditions) were treated as outpatients with the purpose of relieving their pain and improving their function. The quality of care provided was evaluated based on the outcome approach, using patient assessment of the reduction of their pain and improvement of their limitations--complemented by the assessment of the physician who treated them--and their satisfaction with the care as the measurements of their assessments. The results of the assessment indicate that on completion of treatment 23% of patients had no pain, while the pain level of the rest decreased by 64% with only three still suffering from severe pain and none from very severe pain. In the majority of patients considerable improvement of the associated functional limitation was achieved. There was a high degree of satisfaction with care received in 90% of patients.

Mitral valve dysfunction following papillary muscle cryoablation.

Cryoablation is recognized as a useful modality for diagnostic mapping, as well as for permanent obliteration of arrhythmogenic foci. This technique has been used to eradicate irritable foci at the base of papillary muscles. We report a case of mitral valve dysfunction requiring valve replacement following cryoablation of the posterior papillary muscle. Based on this experience, we caution against extensive cryoablation of papillary muscle tissue because of the possibility of disrupting mitral valve function.

Review of Ehlers-Danlos syndrome. Successful repair of rupture and dissection of abdominal aorta.

Successful surgical treatment of spontaneous rupture and dissection of the abdominal aorta in Ehlers-Danlos syndrome has not been previously reported. A 16-year-old male sustained spontaneous rupture and dissection of the abdominal aorta. Successful surgical treatment included placement of an abdominal aortic bifurcation graft. Genetical, biochemical and clinical differences of seven types of the syndrome are outlined. A brief guideline for treatment and prevention of vascular complications is discussed.

Short-term effect of coronary artery bypass grafting on the signal-averaged electrocardiogram.

Ventricular late potentials at the end of the QRS can be detected on the body surface during sinus rhythm by recording a signal-averaged electrocardiogram (SAECG). In patients with coronary artery disease, these late potentials have been shown to be markers for spontaneous or inducible ventricular tachycardia, or both. The short-term (before and 10 +/- 4 days after coronary revascularization) influence of coronary artery bypass grafting (CABG) on the quantitative SAECG variables was studied in 40 patients with chronic coronary artery disease. Twenty-five of these patients had a previous myocardial infarction. In the 15 patients without previous myocardial infarction, no abnormal SAECG indexes were recorded before CABG and no change in the quantitative SAECG variables was observed after surgery. In the patients with a previous myocardial infarction, 7 (28%) had a late potential before CABG. After CABG, 5 (71%) patients remained late potential-positive, whereas the other 2 (29%) lost their late potential. The mean values of their SAECG variables improved after coronary revascularization. In the entire group of postmyocardial infarction patients, the high-frequency QRS duration had shortened (p less than 0.01) after CABG (the other SAECG indexes did not change). The postoperative arrhythmic complications (transient atrial fibrillation, new onset of ventricular couplets) tended to be more frequent in the postmyocardial infarction group and in patients with late potentials. Our findings suggest that the reported increase in ventricular arrhythmias after CABG is probably not related to a change in the arrhythmogenic substrate for ventricular reentry but is associated with changes in the arrhythmogenic milieu.

Minimal positive end-expiratory pressure (PEEP) may be "best PEEP".

In the absence of clinical trials, positive end-expired pressure (PEEP) has been accepted as efficacious for treatment of postoperative decreases in arterial oxygen tension (PaO2) from a variety of causes including adult respiratory distress syndrome (ARDS). PEEP is thought to increase PaO2 by alveolar recruitment, which in turn, has been hypothesized to play a decisive role in pulmonary recovery. One hundred and eighteen patients were followed prospectively, and after development of decreased PaO2, randomized to receive recruitive PEEP (determined by blood gas criteria) or supportive PEEP (the minimal PEEP required to maintain PaO2 above 60 mm Hg on .5 inspired O2 fraction (FIO2). No prognostic factors were significantly different between the two groups. Recruitive PEEP application in 22 patients yielded a significantly increased incidence of hypotension (55 percent), pneumothorax (20 percent), and death during treatment (27 percent) when compared to the 28 supportive PEEP patients who had no hypotension or pneumothorax and only one death during treatment (4 percent). After PEEP treatment, deaths in each group were similar (19 percent and 15 percent, respectively). We find no evidence that PEEP treatment promotes beneficial outcomes and conclude that recruitment attempts may be harmful.