Medicina, Volume 43, Issue 5 (May 2007) – 10 articles

There is a strong need for more studies devoted to the analysis of changes in physiological processes during the incremental bicycle exercise when increasing the intensity of physical activity, serious ischemic episodes in cardiac muscle occur. The aim of this study was a synchronous observation of physiological changes during bicycle ergometry. Participants of the study were 27 healthy male volunteers. All participants of the study performed a graded exercise test to maximal efforts. A 12-lead electrocardiogram was recorded during exercise test and the first three minutes of recovery. Heart rate and ST-segment depression (sum of negative amplitudes) was analyzed. InSpectra Standad System Model 325 (Hutchinson Technology, Hutchinson, Minnesota, USA) was used for the registration of changes in oxygen saturation during exercise and recovery. The InSpectra sensor was placed on m. vastus lateralis. The results obtained in this study showed that changes in oxygen saturation depended on the intensity of workload. During the incremental increase in workload, oxygen saturation decreased in active muscles. While performing the final stages of exercise, a gradual increase in oxygen saturation is observed in the muscles of some participants. Increasing the intensity of physical activity to maximal efforts, rise in oxygen saturation (second phase) coincides with augmentative ischemic episodes in cardiac muscle.
Full article

Acute right ventricular failure is a syndrome, which is related to pulmonary and right heart dysfunction. It may occur with or without cardiopulmonary pathologies. It is often life threatening and requires early recognition and urgent treatment. In this review article, precipitating factors for right ventricular failure and its pathophysiological mechanisms, clinical picture and hemodynamic manifestations, the principles of the management of acute right ventricular failure (optimization of preload, increase in cardiac output, specific pulmonary vascular vasodilators, problems of mechanical ventilations, etc.) are discussed. Full article

The aim of this study was to establish a mathematical model of the infiltration of sodium chloride solution into cadaveric liver tissue.
Methods. The time law of the flow of the infiltrated fluid at every node of the finite element model was obtained in terms of Darcy’s velocity, pressure, and volumetric saturation fraction. The model equations interpret the liver tissue as a porous medium taking into account the hydraulic conductivity, capacity, and absorption mechanisms. Capability of the cadaveric liver tissue to absorb the fluid is taken into account by means of the nonlinear relationship of hydraulic capacity and absorption coefficients against the volumetric saturation fraction. To explain certain inadequacies between the computational model and experiment, the idealized models of empty blood vessels in the vicinity of the injection probe have been used. The model has been implemented in computational environment COMSOL Multiphysics. Experimental procedures were performed to analyze fluid infiltration and to calculate volume of fluid, which might be injected into certain volume of nonviable liver tissue.
Results. The necessary physical constants of hydraulic conductivity, capacity, and absorp- tion of liver tissue have been determined by comparing the simulation results against the experimental data. The congruence of the modeling results against the experiment may be regarded as satisfactory.
Conclusion. The established model analyses distribution of injected solution taking into account the hydraulic conductivity, capacity, and absorption mechanisms of liver tissue. The obtained results are of importance developing complex models of electro-thermal heating coupled with heat advection by means of infiltrated sodium chloride solution. Full article

The aim of the study was to create the model of the combination of clinical and echocardiographic determinants during the acute period of acute coronary syndromes for the prognostication of the risk for left ventricular dysfunction after one year. We examined 565 patients with first-time acute coronary syndrome with no recurrence during one-year period. The studied group consisted of 496 patients, and the examined group – of 69 patients. All patients with acute coronary syndrome within the first three days underwent the evaluation of demographic, anamnesis, clinical indicators, risk factors for ischemic heart disease, ECG, and echocardiographic findings for the prognostication of the risk of left ventricular dysfunction after one year. Multiple logistic regression analysis was applied for the identification of independent determinants for the prognostication of left ventricular dysfunction, and three risk groups were identified. The prognostic informative value of the model was verified by comparing the incidence of left ventricular systolic dysfunction in risk groups after one year between the studied and the control groups.
Results. After one year, left ventricular systolic dysfunction (left ventricular ejection fraction <40%) in the presence of acute coronary syndrome remained in more than half (65.3%) of patients and returned to normal (left ventricular ejection fraction ³40%) in one-third of patients (34.7%). Left ventricular systolic function that was normal during the acute period of coronary syndrome remained such in the majority (80.9%) of patients after one year, whereas one-fifth (19.1%) of patients developed left ventricular systolic dysfunction. The mathematical model for the prognostication of systolic dysfunction after one year was composed of the determinants of acute coronary syndrome: left ventricular ejection fraction <40%, anterior localization of Q-wave myocardial infarction, Killip class 3–4, left ventricular pseudo-normal or restrictive diastolic function, and frequent ventricular extrasystoles. The application of our model in the prognostication of late left ventricular systolic dysfunction during the acute period of coronary syndrome showed that the model was reliable, since after one year, the prognosticated left ventricular systolic dysfunction was determined in the majority (84.3%) of patients. The designed mathematical model is simple and is based on standard clinical and echocardiographic findings, and the scoring system allows for the prognostication of the risk for late left ventricular systolic dysfunction in any individual patient. The prognostication of the risk for late left ventricular systolic dysfunction during the acute period of coronary syndrome may help in the planning of treatment and outpatient care in patients with acute coronary syndrome. Full article

In the recent years, surface plasmon resonance (SPR) has become one of the major methods for studying and determination of biologically active materials exhibiting affinity interactions. SRP biosensors are increasingly used in biochemistry and bioanalytical chemistry to determine antibody-antigen interactions, to investigate DNA hybridization, to diagnose bacteria- and virus-induced diseases, to identify hormones, steroids, and immunoglobulins, to investigate blood plasma coagulation. Using SPR biosensors, it is possible to analyze the mixtures of substances with a very similar chemical structure because SPR allows identifying only those analytes that specifically interact with biologically active substance immobilized on the surface of SPR biosensor. SPR biosensors are applied to monitor interactions between immobilized biologically active substance and analyte in real-time without labeling. On the other hand, it is possible to investigate not only association of analyte with immobilized material, but also the dissociation of a newly formed complex. SPR biosensors in many cases may be used to perform up to 50 measurements with the same SPR chip with an immobilized biological recognition element. Therefore, at present SPR is one of the most promising methods for determining the interactions between ligand and receptor, antigen and antibody, thus being increasingly used in diagnostics and biomedical research. Full article

Depression is one of the leading causes of disability worldwide, affecting 121 million people in whole world. In many developed countries, the number of prescriptions for antidepressants increased steeply during the 1990s. The objective of the present study was to evaluate the antidepressant prescribing patterns in all regions of Lithuania during 2003–2004, to analyze the use within different antidepressant groups, and to examine trends in age- and gender-specific antidepressant use. Antidepressants were classified into three groups according to Anatomic Therapeutic Chemical (ATC) Classification specifying the defined daily doses. The results of our study show an increase in the use of reimbursed antidepressants except tricyclic in 2004 when compared to 2003. Increase in the use of selective serotonin reuptake inhibitors and other nontricyclic antidepressants is probably related to their better tolerability, improved risk-benefit ratio, and less toxicity in overdose. There was no increase in the percentage of consumed selective serotonin reuptake inhibitors in elderly patients when compared with younger ones, despite elderly patients are most likely to benefit from reduced sedation, less antimuscarinic and less cardiac toxicity of selective serotonin reuptake inhibitors. The prevalence of the antidepressant use is the highest among middle-aged people (40–59 years), while the young (under 20) and elderly (older than 70) patients receive mostly selective serotonin reuptake inhibitors. Additional studies should be carried out in order to assess drug-prescribing patterns in accordance with the guidelines of depression treatment in Lithuania considering diagnosis, dosage, and duration of treatment. Full article

The objective of this study was to determine whether empathy and occupational commitment significantly contribute to the emotional exhaustion of nurses. The sample group was 158 nurses from two regional Lithuanian hospitals, who completed self-report measures. A questionnaire consisted of 10 items reflecting empathy appearing on Davis (1983) Indi- vidual Reactivity Index, 4 occupational commitment items from Miller et al. (1988), and 7 emotional exhaustion items from the Maslach Burnout Inventory (Maslach, Jackson, 1981). Correlation analyses and structural equation modeling were employed to interpret the results. The results showed that nurses’ occupational commitment plays an important role in the degree of emotional exhaustion they experience. Nurses having more empathy are more likely to develop higher occupational commitment. In addition, it was found that higher levels of empathy and occupational commitment of nurses are associated with lower emotional exhaustion. Nurses who stayed in the profession longer developed stronger occupational commitment. Therefore, the conclusion was made that differences in emotional exhaustion among nurses may be explained directly by occupational commitment and indirectly by empathy and nursing experience. Full article

Analysis of published scientific data suggests that cytomegalovirus infection has an effect on aging process in human, in particular on immunosenescence, resulting in an increased incidence of infectious diseases and consequent mortality in elderly individuals. The purpose of this study was to evaluate the association between cytomegalovirus infection and a character of aging (premature, physiological, and slow).
Materials and methods. In accordance with special criteria of the assessment of biological age, 146 healthy elderly women aged 60–90 years were divided into three groups: Group 1 – slow aging group (37 women, 25.4%); Group 2 – physiological aging group (58 women, 39.7%); Group 3 – premature aging group (51 women, 34.9%). Immune response to cytomegalovirus was studied using methods of enzyme immunoassay and indirect immunofluorescence.
Results. Comparing immune response to cytomegalovirus in different aging groups, highest titres of both IgG antibodies against early antigens and IgA antibodies against late structural antigens were found in premature aging group. Results showed that premature aging was associated with an increased level of IgA antibodies characteristic for cytomegalovirus symptomatic infection and its frequent reactivations.
Conclusion. Cytomegalovirus infection is associated with an increased risk of premature aging (OR=9.8; P<0.01). Full article

Objective. The sympathetic nervous system participates in the modulation of cerebrovascular autoregulation. The most important source of sympathetic innervation of the cerebral arteries is the superior cervical ganglion. The aim of this study was to investigate signs of the neurodegenerative alteration in the sympathetic ganglia including the evaluation of apoptosis of neuronal and satellite cells in the human superior cervical ganglion after ischemic stroke, because so far alterations in human sympathetic ganglia related to the injury to peripheral tissue have not been enough analyzed.
Materials and methods. We investigated human superior cervical ganglia from eight patients who died of ischemic stroke and from seven control subjects. Neurohistological examination of sympathetic ganglia was performed on 5 μm paraffin sections stained with cresyl violet. TUNEL method was applied to assess apoptotic cells of sympathetic ganglia.
Results. The present investigation showed that: (1) signs of neurodegenerative alteration (darkly stained and deformed neurons with vacuoles, lymphocytic infiltrates, gliocyte proliferation) were markedly expressed in the ganglia of stroke patients; (2) apoptotic neuronal and glial cell death was observed in the human superior cervical ganglia of the control and stroke groups; (3) heterogenic distribution of apoptotic neurons and glial cells as well as individual variations in both groups were identified; (4) higher apoptotic index of sympathetic neurons (89%) in the stroke group than in the control group was found.
Conclusions. We associated these findings with retrograde reaction of the neuronal cell body to axonal damage, which occurs in the ischemic focus of blood vessels innervated by superior cervical ganglion. Full article

The aim of this study was to review our experience in applying acetylcholinesterase histochemistry for diagnosing colonic dysganglionoses in children. Patients and methods. We analyzed acetylcholinesterase histochemistry results of rectal biopsy specimens obtained from 85 children. The indications for biopsy were suspicion of Hirschsprung’s disease in neonates and infants (Group 1; n=21) and older children (Group 2; n=17); megarectum (Group 3; n=44); and colostomy (Group 4; n=3). Specimens were taken at 5 and 10 cm using endoscopic forceps or excised with scissors at 2.5 cm above the dentate line. Acetylcholinesterase activity was evaluated using Karnovsky-Roots method.
Results. The diagnosis of Hirschsprung’s disease was confirmed in 17 children of the first group and in 3 of the second group. In the third group, 2 children were diagnosed with ultrashort-segment Hirschsprung’s disease and 3 children with intestinal neuronal dysplasia. In one case, acetylcholinesterase reaction was false positive. Hirschsprung’s disease was diagnosed in 2 children with colostomies; in one case acetylcholinesterase activity caused false-positive results. Colonic dysganglionoses were diagnosed in 78% of infants and in 14% of children over 1 year of age. The diagnostic specificity of acetylcholinesterase in Hirschsprung’s disease was 92%.
Conclusions. 1) The analysis of acetylcholinesterase activity in children’s rectal biopsy specimens is a reliable method for diagnosing Hirschsprung’s disease, especially in infants; 2) This method of examination is irreplaceable in diagnosing ultrashort-segment Hirschsprung’s disease and remains the only method to confirm the diagnosis of this disease; 3) Acetylcholinesterase histochemistry is not sufficiently informative in diagnosing intestinal neuronal dysplasia type B, because authors applying other neurohistochemical investigation methods have reported higher incidence of this disease. Full article