RESUMO
Membrane nanotubes (NTs) and their networks play an important role in intracellular membrane transport and intercellular communications. The transport characteristics of the NT lumen resemble those of conventional solid-state nanopores. However, unlike the rigid pores, the soft membrane wall of the NT can be deformed by forces driving the transport through the NT lumen. This intrinsic coupling between the NT geometry and transport properties remains poorly explored. Using synchronized fluorescence microscopy and conductance measurements, we revealed that the NT shape was changed by both electric and hydrostatic forces driving the ionic and solute fluxes through the NT lumen. Far from the shape instability, the strength of the force effect is determined by the lateral membrane tension and is scaled with membrane elasticity so that the NT can be operated as a linear elastic sensor. Near shape instabilities, the transport forces triggered large-scale shape transformations, both stochastic and periodic. The periodic oscillations were coupled to a vesicle passage along the NT axis, resembling peristaltic transport. The oscillations were parametrically controlled by the electric field, making NT a highly nonlinear nanofluidic circuitry element with biological and technological implications.
Assuntos
Nanotubos , Membrana Celular/metabolismo , Transporte de Íons , Microscopia de Fluorescência , Dinâmica não Linear , Tensão SuperficialRESUMO
For the development of methods of additional differential diagnostics of gliomas of various grades of malignancy and gliomas and local inflammatory processes in the CNS we studied the intensity of aggregation of peripheral blood cells under the influence of channel blockers ketamine and verapamil. In in vitro experiments, verapamil and ketamine in various dilutions (from 10 to 100,000 times) were added to blood samples and the effects of these dilutions on the intensity of blood aggregation in patients with gliomas of different degree of malignancy, traumatic brain injuries, and other types of neurosurgical pathologies were studied. A correlation was revealed between the decrease in surface charge of blood cells and the type of neurosurgical pathology. The use of functional properties of potential-dependent inotropic NMDA receptors and calcium channels allowed indirect estimation of their activity via parameters of blood cell aggregation induced by channel blockers ketamine and verapamil.
Assuntos
Lesões Encefálicas Traumáticas/diagnóstico , Bloqueadores dos Canais de Cálcio/farmacologia , Glioblastoma/diagnóstico , Ketamina/farmacologia , Meningomielocele/diagnóstico , Verapamil/farmacologia , Lesões Encefálicas Traumáticas/sangue , Estudos de Casos e Controles , Agregação Celular/efeitos dos fármacos , Diagnóstico Diferencial , Glioblastoma/sangue , Humanos , Meningomielocele/sangue , Período Pré-Operatório , Receptores de N-Metil-D-AspartatoRESUMO
Changes in the frequencies of genotypes and mutant alleles of ACE, AGTR1, AGT, and ITGB3 genes were analyzed in patients with arterial hypertension coupled with metabolic syndrome (N=15) and compared with population data and corresponding parameters in patients with isolated hypertension (N=15). Increased frequency of genotype ID of ACE gene (hypertension predictor) was confirmed for both groups. In case of isolated hypertension, M235M genotype (gene AGT) was more frequent, in case of hypertension combined with metabolic syndrome, the frequency of genotypes A1166C and C1166C of the gene AGTR1 was higher in comparison with population data. Comparison of mutant allele frequencies in the two groups showed that at the 90% significance level allele T of the AGT gene was more frequent in hypertension coupled with metabolic syndrome (OR=1.26) and genotype A1166A of the AGTR1 gene was more frequent in the group with isolated hypertension.
Assuntos
Hipertensão/genética , Síndrome Metabólica/genética , Polimorfismo Genético/genética , Idoso , Angiotensinogênio/genética , Feminino , Frequência do Gene , Predisposição Genética para Doença/genética , Genótipo , Humanos , Integrina beta3/genética , Masculino , Pessoa de Meia-Idade , Peptidil Dipeptidase A/genética , Receptor Tipo 1 de Angiotensina/genética , Sistema Renina-Angiotensina/genéticaRESUMO
The expression of Bax protein, marker of intracellular pathway of apoptosis initiation, in viable left ventricular cardiomyocytes and morphological changes in the myocardium in acute pressure overload of the left ventricle were studied in experiment on male rabbits. The content of Bax protein in the cardiomyocyte cytoplasm decreased, this indicating that the mitochondrial pathway was not involved in the realization of the apoptotic program. This decrease was associated with manifest destructive changes in the left ventricular myocardium.
Assuntos
Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , Proteína X Associada a bcl-2/metabolismo , Animais , Ventrículos do Coração/metabolismo , Ventrículos do Coração/patologia , Masculino , Miocárdio/patologia , Coelhos , Pressão VentricularRESUMO
In experiments on rabbits we evaluated the intensity of cardiomyocyte autophagia by the level beclin-1 protein and morphology of the left ventricular myocardium on days 1, 3, and 5 after the onset of focal ischemia caused by ligation of the descending branch of the left coronary artery. The morphological alterations in the left ventricular myocardium were accompanied by intensification of cardiomyocyte autophagia, which attained maximum on postligation day 1.
Assuntos
Isquemia Miocárdica/patologia , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Autofagia/fisiologia , Masculino , Isquemia Miocárdica/metabolismo , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Coelhos , Função Ventricular Esquerda/fisiologiaRESUMO
In SHR rats of different ages (22, 26, 30, 34, and 38 weeks), continuous 24-h telemetric monitoring of BP and HR was performed. The amplitude and power of oscillations of diastolic BP significantly decreased at the later stages of arterial hypertension (38 weeks), which was considered as a poor prognostic marker. We also observed a significant decrease in the mean daytime, nighttime, and maximum HR and mesor on weeks 30 and 34, but not on week 38, which can reflect triggering of the adaptive response followed by its exhaustion.
Assuntos
Pressão Sanguínea/fisiologia , Ritmo Circadiano/fisiologia , Frequência Cardíaca/fisiologia , Hipertensão/fisiopatologia , Animais , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos WistarRESUMO
We studied the effect of phosphocreatine and ethylmethylhydroxypyridine succinate on the expression of Bax and Bcl-2 proteins in left-ventricular cardiomyocytes of spontaneously hypertensive rats (SHR). Both drugs have no effect on the expression of Bcl-2, but significantly reduce the level of Bax protein (phosphocreatine produces more pronounced effect). These data attest to an important role of energy deficit and oxidative stress in the induction of cardiomyocyte apoptosis in genetically determined arterial hypertension.
Assuntos
Regulação da Expressão Gênica/efeitos dos fármacos , Ventrículos do Coração/efeitos dos fármacos , Hipertensão/metabolismo , Fosfocreatina/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Piridinas/farmacologia , Proteína X Associada a bcl-2/genética , Animais , Apoptose/efeitos dos fármacos , Masculino , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Picolinas/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos , Ratos Endogâmicos SHR , Proteína X Associada a bcl-2/metabolismoRESUMO
Aim of this study was to analyze the state of coronary arteries in patients with acute coronary syndrome according to polymorphism of integrin ß-3 (ITGB3) gene. All patients were divided into 2 groups: carries and non-carries of PLA2 allele. Carriers of PLA2 allele compared with noncarriers had lesser grades of coronary artery stenoses but greater number of involved arteries. Carriers had more repetitive acute coronary events.
Assuntos
Síndrome Coronariana Aguda , Vasos Coronários/patologia , Integrina beta3/genética , Síndrome Coronariana Aguda/diagnóstico , Síndrome Coronariana Aguda/genética , Síndrome Coronariana Aguda/fisiopatologia , Idoso , Angiografia Coronária , Feminino , Triagem de Portadores Genéticos , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Recidiva , Índice de Gravidade de DoençaRESUMO
The specific features of circadian rhythm of BP were investigated in freely moving male SHR rats using telemetry monitoring technique. BP was recorded in the abdominal aorta according to 24-h/4-month schedule. The data were obtained from 22, 26, 30, 34, and 38-week-old animals. Normotensive Wistar rats (22 weeks) served as the control. It was found that the mean 24-h, daytime, and nighttime systolic and diastolic BP in hypertensive rats significantly surpassed the control throughout the observation period and practically did not change during prolonged hypertension. Some prognostically negative changes in the circadian rhythm of the basic hemodynamics system parameters appeared with time. For instance, the maximum 24-h systolic BP significantly increased in comparison with the initial level.
Assuntos
Aorta Abdominal/fisiopatologia , Ritmo Circadiano , Hipertensão/fisiopatologia , Animais , Pressão Sanguínea , Diástole , Progressão da Doença , Frequência Cardíaca , Hemodinâmica , Masculino , Atividade Motora , Ratos , Ratos Endogâmicos SHR , Ratos Wistar , Sístole , TelemetriaRESUMO
PLA polymorphism of platelet integrin receptor, GpIIIa glycoprotein, (PLA polymorphism of the ITGB3 gene) is associated with the risk of myocardial infarction and CHD especially in young subjects. We analyzed ITGB3 gene polymorphism in patients with acute coronary insufficiency. It was shown that increased AP and altered blood lipid spectrum in the acute period of disease in carriers of the PLA allele (PLA1/PLA2 and PLA2/PLA2 genotypes) can be regarded as manifestations of stress reaction. The data obtained indicate that the PLA2 allele is a predictor of complications of acute coronary insufficiency. This observation is of importance for the choice of adequate therapy for the patients with this disorder.
Assuntos
Síndrome Coronariana Aguda/genética , DNA/genética , Hipertensão/epidemiologia , Integrina beta3/genética , Polimorfismo Genético , Síndrome Coronariana Aguda/complicações , Idoso , Idoso de 80 Anos ou mais , Alelos , Feminino , Genótipo , Humanos , Hipertensão/complicações , Hipertensão/genética , Incidência , Integrina beta3/metabolismo , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Federação Russa/epidemiologiaRESUMO
Activities of caspase-3 and caspase-8 in the left ventricular myocardium of Chinchilla rabbits with renovascular arterial hypertension and spontaneously hypertensive rats were measured after 10-day administration of a macroergic compound phosphocreatine. Treatment with phosphocreatine prevented activation of caspase-3, but had no effect on caspase-8 during secondary and genetically determined arterial hypertension. Our results indicate that the intrinsic mechanism of the induction of the caspase cascade in myocardial cells dominates over the extrinsic pathway during both types of arterial hypertension. Energy deficit is one of the inducing factors of these processes.
Assuntos
Apoptose/efeitos dos fármacos , Cardiotônicos/farmacologia , Metabolismo Energético/efeitos dos fármacos , Ventrículos do Coração/química , Hipertensão Renovascular/metabolismo , Miocárdio/metabolismo , Fosfocreatina/farmacologia , Animais , Cardiotônicos/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Caspase 8/genética , Caspase 8/metabolismo , Expressão Gênica/efeitos dos fármacos , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/metabolismo , Hipertensão Renovascular/tratamento farmacológico , Hipertensão Renovascular/genética , Hipertensão Renovascular/fisiopatologia , Masculino , Fosfocreatina/metabolismo , Coelhos , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKYRESUMO
Cardiomyocyte apoptosis and hypertrophy have been studied in the left and right ventricular myocardium of spontaneously hypertensive rats without treatment and after 10-day administration of the ETA-receptor antagonist BQ-123. It is established that BQ-123 prevents the activation of cardiomyocyte apoptosis and significantly decreases the extent of hypertrophy development in the left ventricular myocardium, but does not influence the same mechanisms in the right ventricular myocardium.
Assuntos
Anti-Hipertensivos/farmacologia , Ventrículos do Coração/efeitos dos fármacos , Hipertrofia Ventricular Esquerda/prevenção & controle , Miócitos Cardíacos/efeitos dos fármacos , Peptídeos Cíclicos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Antagonistas do Receptor de Endotelina A , Ventrículos do Coração/metabolismo , Ventrículos do Coração/fisiopatologia , Hipertrofia Ventricular Esquerda/metabolismo , Hipertrofia Ventricular Esquerda/fisiopatologia , Hipertrofia Ventricular Direita/metabolismo , Hipertrofia Ventricular Direita/fisiopatologia , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Receptor de Endotelina A/metabolismoRESUMO
Acute left ventricular (LV) overload was simulated in rabbits, by applying a metal spiral to narrow the ascending aorta by one third of its baseline diameter. A control group comprised intact animals. Studies were conducted 1, 3, and 5 days after surgery for simulation of LV overload in parallel series. In the first series of the experiment, semifine LV sections were examined by light microscopy and morphometry. The rate of cardiomyocyte (CMC) apoptosis was estimated calculating the free lying nuclei--the morphologically unchanged nuclei that were present in the extracellular space. In the second series, CMC apoptosis underwent immunohistochemical assessment, by running the TUNEL test. During its acute hemodynamic overload, the LV myocardium showed significant tissue destruction and a substantially lower number of viable myofibrils, and an increase in the count of apoptotically altered CMCs.
Assuntos
Apoptose , Miocárdio , Miócitos Cardíacos , Disfunção Ventricular Esquerda , Animais , Modelos Animais de Doenças , Imuno-Histoquímica , Masculino , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Coelhos , Disfunção Ventricular Esquerda/metabolismo , Disfunção Ventricular Esquerda/patologiaRESUMO
The study analyzed changes in parameters of the central and intracardiac hemodynamics during the development of experimental arterial hypertension, which were assessed as the adaptive in nature. The development of hypertension demonstrated staging of the adaptive processes. The development of the adaptive responses was characterized by changes in the magnitude and probabilistic distribution of the hemodynamic parameters.
Assuntos
Coração/fisiopatologia , Hipertensão Renal/fisiopatologia , Hipertensão/fisiopatologia , Adaptação Fisiológica , Animais , Pressão Sanguínea , Diástole , Modelos Animais de Doenças , Entropia , Humanos , Masculino , Coelhos , Estatística como Assunto , Sístole , Pressão VentricularRESUMO
Focal left ventricular ischemia was modeled in male Chinchilla rabbits. Activities of caspase-3 and caspase-8 in the left and right ventricular myocardium and myocardial contractility were studied after 1, 3, and 5 days. Caspase-3 activity increased significantly in the left ventricular peri-infarction zone and right ventricular myocardium, while caspase-8 activity did not differ from the control. Left ventricular contractility decreased significantly and the hemodynamic load of the right ventricle sharply increased. These results attest to induction of the internal (mitochondrial) pathway of apoptosis in myocardial cells most likely caused by left ventricular hypoxia and right ventricular overload.
Assuntos
Caspase 3/metabolismo , Caspase 8/metabolismo , Isquemia/patologia , Contração Miocárdica/fisiologia , Função Ventricular Esquerda/fisiologia , Animais , Apoptose , Vasos Coronários/patologia , Vasos Coronários/cirurgia , Coração , Ventrículos do Coração , Masculino , Miocárdio/metabolismo , Coelhos , Função Ventricular Direita/fisiologiaRESUMO
Numerous experiments on simulation of acute coronary failure in initially intact rabbits showed that under the same experimental conditions irreversible ventricular fibrillation developed in some animals and did not develop in other. We hypothesize that the probability of fibrillation development was determined by the time of the day, during which acute coronary failure developed. The study was carried out on 2 groups of rabbits in winter in Moscow. In group 1, the failure was induced by ligation of the left descending coronary artery at the interface between its middle and lower thirds at 11.00-18.00 with 30-min intervals. In group 2, the microcirculatory status of the left-ventricular myocardium was studied by light microscopy and morphometry at 12.00 and 18.00. Induction of coronary failure during the period from 15.30 to 18.00 led to irreversible ventricular fibrillation and death in 100% cases. Modeling of the condition from 11.00 to 15.00 caused no ventricular fibrillation in 89% cases, and the animals survived. The area of left-ventricular myocardial capillaries at 12.00 virtually 2-fold surpassed that at 18.00. Presumably, the electrolyte balance and metabolic characteristics of the myocardium switch over to the nocturnal mode of functioning at 15.30 due to changes in blood filling of the myocardium. The appearance of an ischemic focus in the myocardium during this period inevitably leads to the development of irreversible ventricular fibrillation.
Assuntos
Ritmo Circadiano , Coração/fisiopatologia , Infarto do Miocárdio/complicações , Fibrilação Ventricular/etiologia , Animais , Capilares/anatomia & histologia , Vasos Coronários , Eletrocardiografia , Ligadura , Masculino , Coelhos , Estações do AnoRESUMO
Diphtheria intoxication was simulated in rabbits, by intravenously injecting native diphtheria toxin in a dose of 0.3 MLD (minimal lethal dose) per kg body weight. Intact rabbits were used as a control. Following 1, 3, and 5 days of the onset on intoxication, the chests were opened under 2% rometar anesthesia and the hearts were extirpated, semithin left and right ventricular myocardial sections were prepared and light microscopic morphometry (at a magnification of x 1000) was carried out with video-assisted imaging. The rate of cardiomyocytic (CMC) apoptosis was determined, by calculating the free lying nuclei - the morphologically changed nuclei that were present in the extracellular space. Both ventricular CMC destruction characteristic of necrotic death was ascertained to significantly increase just on day 1 of the experiment and to further enhance during its course. By day 5, the rate of CMC apoptosis increased in both the left and right ventricles. Furthermore, there was an increasing reduction in myocardial collagen levels.
Assuntos
Apoptose/efeitos dos fármacos , Toxina Diftérica/toxicidade , Ventrículos do Coração , Miocárdio , Miócitos Cardíacos , Animais , Colágeno/metabolismo , Modelos Animais de Doenças , Ventrículos do Coração/metabolismo , Ventrículos do Coração/patologia , Humanos , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Necrose , CoelhosRESUMO
The authors analyse effect of GPIIIA gene (PI a allele) polymorphism on the frequency of complicated coronary heart disease in patients with dyslipidemia and hypertensive disease. Specific features of ventricular repolarization (T-wave variability) in patients with acute coronary syndrome are described.
Assuntos
Síndrome Coronariana Aguda/genética , DNA/genética , Eletrocardiografia , Integrina beta3/genética , Polimorfismo Genético , Síndrome Coronariana Aguda/complicações , Síndrome Coronariana Aguda/fisiopatologia , Adulto , Idoso , Alelos , Dislipidemias/sangue , Dislipidemias/complicações , Dislipidemias/genética , Frequência do Gene , Humanos , Hipertensão/sangue , Hipertensão/complicações , Hipertensão/genética , Integrina beta3/sangue , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , PrognósticoRESUMO
It's well known that chronic overload of the cardiac left ventricle is accompanied by an increase in the cardiomyocyte apoptosis rate. However direction and extent of programmed cell death changes under an acute overload of the left ventricle still requires detailed investigation. Caspase-3 activity has been investigated in myocardium of rabbits on the 1, 3 and 5 days after modeling of left ventricle hemodynamic overload caused by surgical narrrowing of the ascending aorta. Control group included intact animals. It was found that caspase-3 activity significantly increased in both ventricles on day 1; it increased more than twofold above controls on day 3; it began to decrease by day 5. On the basis of the obtained data it was concluded that: an acute hemodynamic overload of the left ventricle is a cause of apoptosis acceleration in the myocardial tissue of both cardiac ventricles during first days of the investigated process.
Assuntos
Caspase 3/metabolismo , Ventrículos do Coração/metabolismo , Hemodinâmica , Miocárdio/metabolismo , Remodelação Ventricular , Animais , Masculino , Coelhos , Fatores de TempoRESUMO
Diphtheria intoxication was induced in rabbits by a single intravenous injection of native diphtheria toxin in dose of 0.3 MLD/kg, preliminary titrated on guinea pigs. Significant decrease in diastolic and systolic blood pressure and in intraventricular pressure in the left ventricle was established to take place during intoxication. Pulse wave propagation time was prolonged, likely due to prolongation of pressure wave, while the reflection wave appeared at the same time. Reduction of central blood pressure was concluded to result from changes in biomechanical characteristics of the left ventricle, and not to be associated with changes in elastic properties of the arterial wall.