Pulsatile Features of Major Arteries in Rats during Hypotension Caused by Acute Blood Loss.

The study examined the modes of pulsations of the femoral and carotid arteries of rats in situ (n=14) during acute blood loss, which sequentially caused a deep BP drop, cardiac and respiration arrest, and termination of ECG signals. When BP dropped to 19 (13; 26) mm Hg, the mechanosensitivity of passively pulsing arteries determined by the ratio of the swing range of electroimpedance oscillations of arterial segment to pulse pressure increased by 3.2 (2 ; 4) times (p<0.05). During the decrease of BP to the threshold value of 13 (8; 15) mm Hg, the arterial pulsing mode changed from passive to intermediate and then to the active one characterized by constriction of arterial segment in response to systolic elevation of BP. After cardiac arrest and BP drop almost to zero, the arterial pulsing switched to autonomic rhythmical vasomotions with the rate, which was greater than the frequency of still sustained QRS pulses of ECG. The observed phenomena are explained by transarterial hypotensive transition hypothesis, which argues that peculiarities of pulsations and vasomotions of major arteries during deep BP drop are typical of arterioles under normal or diminished BP. The study refined the hypothesis of "peripheral heart" and its role in hypo- and hypertension.

Chronic Effects of Modeled Myocardial Infarction, Thoracic Trauma, and Denervation of Hind Limb on Rheographic Parameters of Rat Femoral Arteries In Situ.

In experiments on narcotized male rats (n=85), the mean electroimpedance Z and peak-to-peak magnitudes (the swing ranges) of passive (ΔZp) and active (ΔZa) pulsatile electroimpedance oscillations of isolated segment of femoral arteries were determined in situ. These rheographic parameters (RP) were measured in intact animals and in those with modeled chronic myocardial infarction, chronic denervation of the right hind leg, as well as in rats subjected to sham operations to mimic denervation or infarction (with thoracic trauma). The rats with modeled myocardial infarction demonstrated decreasing trends of all RP. In sham-operated rats with thoracic trauma, ΔZp increased significantly on postsurgery months 2-4 by 4.3 times in comparison with the control. No essential correlation was found in denervated rats between RP of any femoral artery and severity of neuropathic pain syndrome assessed by autotomy of the operated leg. In these rats, the mean electroimpedance Z of any femoral artery was significantly greater than the control level. They demonstrated especially high values of ΔZp with significant difference between ΔZp of innervated and denervated hind leg. In denervated rats, ΔZa was significantly greater than the control value without significant difference between ΔZa of both femoral arteries. The paradoxically great increase of ΔZp (100- and 50-fold for innervated and denervated legs, respectively) and a significant 3-fold increment of ΔZa in both hind legs provoked by denervation of one of them are discussed in relation to searching for the ways of systemic influences on vascular network in clinics and experiments.

Relationship between Passive and Active Pulsations of Rat Artery as Vascular Extension of Frank-Starling Law.

The experiments on narcotized male rats (n=30) determined the parameters of passive and active pulsatile modes of isolated segment of femoral artery in situ. Rheographic elasticity (RE) and reactivity (RR) were correspondingly determined as the ratios of peak-to-peak (p2p) magnitudes of passive and active pulsatile oscillations of arterial electroimpedance (AEI) to p2p magnitude of BP undulations. The medians and interquartile ranges of RE and RR were 6 (3; 11) and 70 (40; 110) mΩ/mm Hg, respectively. The maximal and minimal values of RE and RR in various rats differed by 50 and 80 times, respectively, and were bimodally distributed: in major group (n=23), the values were RE<15 and RR<200 mΩ/mm Hg, whereas in minor group (n=7), these parameters were RE>20 and RR>300 mΩ/mm Hg. The above ranges of RE and RR parameters were considered as the diagnostic signs of normal and pseudo-healthy rats with pathologically augmented AEI oscillations, respectively. Statistical analysis of all rats (n=30) revealed the positive correlation between RE and RR (r=0.76) with linear regression RR=31+7.6×RE. It is hypothesized that this correlation is underlain by a mechanism similar to that described by the Frank-Starling law for myocardium.

[The determining factors of qualitative training of students in public health and health care].

The inclusion of public health and health care measures in labor functions of professional standards of medical specialists increased significance of mastering of these standards by students during specialty training, since on this depends their successful completion of primary accreditation of specialists and implementation of job descriptions in the course of daily activities. The purpose of the study was to analyze factors determining qualitative of mastering the discipline "Public health and Health Care" by students of medical educational organizations. The analytical, logical, statistical, questionnaire survey and direct ranking methods were applied. The sampling of 316 students of the Sechenov University was involved in survey using questionnaire of 17 closed questions. The study established that the determining factors effecting quality of mastering by students the discipline "Public health and Health Care" are the need to use by physicians this knowledge in the course of their daily activities; the need of students to pass profile exam; the determination of up to 40% of trainees to work as heads of structural units or professionals of health care and public health; the dedication of student; organization of educational process at the Chair; the professionalism of faculty; the application of active learning methods in classroom; organization of career guidance among students.

Effect of Alternating Electric Current on Pulsation Mode of Rat Major Arteries In Situ.

In experiments on narcotized rats, the electrical potential and impedance of isolated segment of the right femoral and/or carotid artery were simultaneously recorded in situ via two extracellular nonpolarizable Ag/AgCl electrodes mounted along the arteries at the interelectrode distance of 4 mm. The active, passive, and intermediate pulsing modes of arterial segment were determined according to the phase relations between its electrical impedance and BP, which was simultaneously measured in the symmetrical part of the respective left artery and used to assess pressure in the examined segment. The study assessed the effect of amplitude (0.2-2.0 mA) of alternating probe current (100 kHz), which was used to measure the electrical impedance of arterial segment, on its pulsing mode. The pulsing mode determined at the initial minimal probe current of 0.2 mA was passive with out-of-phase pulsatile oscillations of electrical impedance and BP. After elevation of the probe current amplitude to maximal level of 2 mA, these oscillations became in-phase indicating transition of the arterial segment to active pulsing mode. This transition was accompanied by appearance of arterial voltage impulses synchronized with BP upstrokes and an 11-fold median increase in the peak-to-peak value of electrical impedance oscillations with the interdecile range of 7-15 (N=28). Under moderate amplitude of probe current (0.3-0.5 mA), the intermediate mode of arterial pulsing was observed featured by a delayed, weak, and short active constriction during BP front, which was insufficient to resist and counterbalance the dilating effect of rising BP. In this case, the pulsatile oscillations of electrical impedance were smaller than those observed in active or passive pulsing modes indicating a possibility to stabilize the arterial diameter during pulsatile oscillations of BP. The effect of alternating electric current on the mode of arterial pulsation is explained with electrical model of smooth muscle cell membrane reflecting the rectifying features of potassium channels and predicting membrane hyperpolarization in response to external alternating current passing across the cell. The visibilities of therapeutic neurotropic and angiotropic stimulation with alternating electric current are discussed.

Bimodal Electrical Properties of Rat Major Artery Segment In Situ.

In experiments on narcotized rats, BP in the left femoral artery as well as local electrical potential and electrical impedance of the symmetric segment of the right femoral artery were simultaneously recorded in situ with two extracellular nonpolarizable Ag/AgCl electrodes located along the artery at a distance of 3 mm from each other. The pulsatile arterial electrical potentials with amplitude of 100-200 µV and duration of about 50 msec were recorded, which coincided with the front of BP wave corrected for a 10-msec delay of the pressure transducer. Under normal conditions, the pulsatile oscillations of arterial electroimpedance were in-phase with BP oscillations, so the rising phase of BP was paralleled by elevation of electroimpedance reflecting constriction of the arterial segment. This finding is viewed as indicative of periodic myogenic Ostroumov-Bayliss effect triggered by arterial pulse. After local application of tetrodotoxin (3×10-7 М), procaine (0.5%), or lidocaine (spray 10%) to isolated arterial segment, its electroimpedance oscillated out-of-phase with BP, so the changes of electroimpedance were similar to the response of a passive elastic tube to pulsatile BP. The applied agents completely (tetrodotoxin) or pronouncedly (procaine, lidocaine) inhibited the pulsatile arterial electrical potential. The present data indicate the possibility of passive and active modes of arterial pulsing, which differ by the amplitude of pulsatile arterial electrical potential as well as by phasic relations between BP and electroimpedance. The possible physiological role of various modes of pulsing in major arteries is discussed.

Pro- and Antioxidant Systems in the Lower Portion of Rat Brainstem during Hydroxybutyrate-Induced Pathological Periodic Breathing.

Activities of superoxide dismutase and catalase characterizing antioxidant status of the nervous tissue and its resistance to free radical oxidation were measured in the brainstem of rats with hydroxybutyrate-induced pathological periodic breathing. Hydroxybutyrate modified the pro- and antioxidant status in the brainstem respiratory center. It markedly inhibited catalase activity; in rats without the signs of periodic breathing, hydroxybutyrate up-regulated superoxide dismutase activity and to a lesser extent increased the resistance of the membrane structures in the medulla oblongata to induction of free radical oxidation. In rats with periodic breathing pattern, hydroxybutyrate induced more pronounced increase in the sensitivity of membrane structures in the medulla oblongata to induction of free radical oxidation.

Outcome of neuropsychiatric symptoms related to an antiretroviral drug following its substitution by nevirapine: the RELAX study.

OBJECTIVES: The primary objective was to evaluate the improvement in neuropsychiatric symptoms attributed to an antiretroviral drug after that drug was substituted with nevirapine. The secondary objective was to evaluate the impact on patient adherence and quality of life. METHODS: A prospective, observational study was carried out that included patients with HIV-1 plasma suppression for whom an antiretroviral drug was substituted with nevirapine because of central nervous system (CNS) side effects, a Pittsburgh Sleep Quality Index (PSQI) score > 5 or a Hospital Anxiety and Depression Scale (HADS) score ≥ 10, and who had not initiated psychoactive drug treatment during the prior 6 weeks. Evaluations were carried out at baseline and 1 and 3 months after the switch using the PSQI, HADS, Epworth Sleepiness Scale, Medical Outcomes Study-Short Form 30 items (MOS-SF-30) and Simplified Medication Adherence Questionnaire (SMAQ). RESULTS: A total of 129 patients were included in the study. The drug substituted was mainly efavirenz (89.9%), and reasons for the switch included sleep disturbances (75.2%), anxiety (65.1%), depression (38.7%), attention disturbances (31%), and other reasons (31%), with a mean of 2.4 neuropsychiatric disturbances per patient. A statistically significant improvement was observed in all the tests evaluating neuropsychiatric symptoms and adherence at 1 and 3 months. The CD4 lymphocyte count remained stable (P = 0.096). Three (2.3%) patients had a detectable plasma HIV-1 RNA at the end of the study. Nine patients (6.9%) withdrew because of nevirapine-related toxicity (rash in seven patients and hypertransaminasaemia in two patients, none of which were > grade 2). CONCLUSIONS: The switch to nevirapine from a drug causing neuropsychiatric disturbances (primarily efavirenz) in subjects with virological suppression was effective in resolving those disturbances, with an improvement in all the parameters studied. This led to better adherence to treatment and quality of life, with no detrimental effect on their immunological and virological control.

[The role of opioidergic and GABAergic systems in the mechanosensitivity regulation of the respiratory system in rats].

In anaesthetized white outbred male rats we investigated the change of respiratory mechanoreceptors sensitivity to morphine and phenibut. Bilateral transection of the vagus nerves causes a severely slowdown of respiratory rate in 30 minutes after the systemic administration of morphine, however after administration of phenibut the respiratory rate and other respiration parameters have not changed significantly. It means that the activation of opioid receptors by morphine does not significantly affect the function of the respiratory mechanoreceptor control loop, and transection of the vagus nerves on this background increases the probability of respiratory rhythm disorders. Activation of GABAergic system by phenibut significantly weakened the impact of the regulating contour of the respiratory mechanoreceptor on breathing parameters, up to effect of "central vagotomy": that is, to no changes in respiratory parameters after cutting the vagus nerves.

[Surgical treatment of Hirschprung's disease total form in children].

It was analyzed the treatment results of 24 patients under the age of 2 years with total aganglionosis for the period from 2000 to 2013. Each of these patients underwent several surgical interventions (on the average 7.8±2.1). All children were operated radically. It was performed ileojejunorectal anastomosis at transitional fold of peritoneum in patients with concomitant short bowel syndrome. Soave's operation was done in 14 patients including by using of laparoscopic technique in 3 cases. Inflammatory complications (paraproctitis) developed in 2 children on maceration background. Perirectal fistula was observed in 1 patient subsequently. In long-term period liquid stool incontinence persisted up to 6 months in 28% of children. In terms of more than 1 year stool incontinence was observed in 12.6% of patients. Increased growth of D-lactate-producing gram-positive anaerobes was revealed during microbiological investigation of feces in 35% of patients in long-term period. Increased growth was accompanied by systemic acidosis and infectious enteritis clinically. Course monthly treatment with antibacterial drugs (Alpha-Normix, Trichopolum, Gentamicin) was prescribed in patients with short bowel syndrome and high frequent of enteritis recurrence. Treatment was used In terms from 6 to 12 months of longer if it was necessary. It was concluded that timely diagnosis and right tactic in neonatal period leads to decrease significantly the number of complications, vain interventions and to improve treatment outcomes. Our experience shows that the best results of surgical treatment were observed in children aged from 2.5-3 years when a child can control urination and defecation. The most mistakes are caused by wrong or failed morphological investigation of large bowel.

[The resistance of low brainstem tissue to free radical oxidation in rats during periodic breathing following hydroxybutyrate treatment].

We evaluated tissue resistance to free radical oxidation, in pentobarbital-anesthetized mongrel albino male rats during pathologic periodic breathing following hydroxybutyrate (GHBA) administration. It was shown that GHBA modulated pro- and antioxidant status of brain tissue. In the absence of periodic breathing after GHBA, decreases in resistance of brainstem tissue membranes to induction of free radical oxidation were slightly pronounced. Rats with GHBA-induced periodic breathing exhibited increased membrane sensitivity of medullar neurons to induction of free radical oxidation. We suggest that cellular metabolism and/or membrane mechanisms of respiratory rhythm-generating neurons play a role in the pathogenesis of periodic breathing.

[The magnetic foreign bodies of the gastrointestinal tract in children].

The authors own the experience of treatment of 23 children with magnetic foreign bodies (MFB) of the gastrointestinal tract. They share the possibilities of diagnostics and surgical treatment of children on the vivid clinical examples. By MFB in the stomach, which do not leave the gastrointestinal tract naturally, the use of fibroesophagoduodenoscopy is recommended. The laparoscopy is helpful in case of the uncomplicated MFB in the intestine. The X-ray control of the complete foreign bodies evacuation is necessary.

GABA representation in hypoxia sensing: a ventilatory study in the rat.

Phenibut, a nonspecific GABA derivative, is clinically used as an anxiolytic and tranquilizer in psychosomatic conditions. A GABA-ergic inhibitory pathway is engaged in respiratory control at both central and peripheral levels. However, the potential of phenibut to affect the O2-related chemoreflexes has not yet been studied. In this study we seek to determine the ventilatory responses to changes in inspired O2 content in anesthetized, spontaneously-breathing rats. Steady-state 5-min responses to 10% O2 in N2 and 100% O2 were taken in each animal before and 1 h after phenibut administration in a dose 450 mg/kg, i.p. Minute ventilation and its frequency and tidal components were obtained from the respiratory flow signal. We found that after a period of irregular extension of the respiratory cycle, phenibut stabilized resting ventilation at a lower level [20.0±3.3 (SD) vs 31.1±5.2 ml/min before phenibut; P<0.01]. The ventilatory depressant effect of phenibut was not reflected in the hypoxic response. In relative terms, this response was actually accentuated after phenibut; the peak hypoxic ventilation increased by 164% from baseline vs the 100% increase before phenibut. Regarding hyperoxia, its inhibitory effect on breathing was more expressed after phenibut. In conclusion, the GABA-mimetic phenibut did not curtail hypoxic ventilatory responsiveness, despite the presence of GABA-ergic pathways in both central and peripheral, carotid body mechanisms mediating the hypoxic chemoreflex. Thus, GABA-mediated synaptic inhibition may be elaborated in a way to sustain the primarily defensive ventilatory chemoreflex.

Increased survival time or better quality of life? Trade-off between benefits and adverse events in the systemic treatment of cancer.

INTRODUCTION: Primary objective of the study was to assess the relative weighting between benefit in survival time (SV), benefit in quality of life (QoL) and willingness to experience adverse events (AEs), in patient preferences for chemotherapy treatment. MATERIALS AND METHODS: We included cancer patients with current or past systemic treatment of cancer (STC) as well as physicians placed as hypothetical patients. Participants filled a choice-based conjoint analysis questionnaire with 19 choices among three STC scenarios with variable amounts of benefit in SV or QoL and different types AEs. RESULTS: One hundred patients (50 on curative and 50 on palliative intention treatment) and 114 physicians (61 oncologists and 53 non-oncologists) were included and asked about their preferred chemotherapy treatment. The relative weighting (sum 100%) of SV-QoL-AEs for making the choice in the 100 patients was SV35%-CV33%-AEs31% what was not significantly different from a random distribution (Goodness of fit Chi square P = 0.91) just as it was not for both subgroups, palliative (SV37%-QoL29%-AEs34%; GoF Chi square P = 0.55) and curative (SV34%-QoL36%-AEs30%; GoF Chi square P = 0.73) treatment. The observed distribution in the group of 114 physicians (SV46%-QoL31%-AEs23%) was significantly different from a random distribution (GoF Chi square P = 0.018) just as it was for both subgroups, medical oncologists (SV48%-QoL29%-AEs23%; GoF Chi square P = 0.006) and non-medical oncologists (SV44%-QoL33%-AEs23%; GoF Chi square P = 0.04). CONCLUSIONS: The three attributes (SV, QoL, and AEs) are considered in the same way by cancer patients to make choices on their STC. On the contrary, when placed as hypothetical patients, physicians prefer for themselves those treatments that provide more SV.

[Analysis of point mutations in BRCA1 gene using hybridization on hydrogel microchips].

Germ-line mutations in BRCA1 gene account for a substantial proportion of inherited breast and ovarian cancers. Identification of these mutations allows molecular diagnosis for breast cancer susceptibility. We have developed method for identification of 185delAG, 300T>G, 4153delA, 4158A>G and 5382insC mutations in BRCA1 gene using hybridization with microarray of geL-immobilized oligonucleotides (microchip). The microchip was tested with 36 control samples, carrying the above-mentioned mutations and 65 clinical cases with breast cancer. Our data demonstrated that developed microchip can be very effective and realible tool, easily introduced in ordinary medical and genetic laboratories.

Functional analysis of hybrid plasmids carrying genes for lambda site-specific recombination.

A number of hybrid plasmids, carrying lambda genes involved in site-specific integrative recombination, have been constructed in vitro. Analysis of protein synthesis in Escherichia coli minicells has shown that Int protein is synthesized only when int gene is expressed constitutively. The plasmids RSF2124::lambda-CD, RSF2124::lambda-Cint-c57, and pInt lambda were able to integrate into the chromosome of E.coli at the attB. The integration of hybrid plasmids into the genome of bacteria has also been shown for polA1 strains restricting the autonomous replication of ColE1 type plasmids. Genetic markers of hybrid plasmids are maintained in polA1 bacteria for at least 50 generations under nonselective conditions. The Southern blotting experiments using [32P]pBR322 DNA and EcoRI fragments of E. coli polA1 chromosome carrying integrated plasmid pInt lambda demonstrated that in this strain hybrid plasmids can be observed only when integrated into the attB of the chromosome according to Campbell's model of integration. In the cells, where autonomous replication of plasmids is possible, they can be observed both in extrachromosomal and integrated states. The integration of the ColE1 replication origin into the chromosome of bacteria is not lethal for the cells. Only attP and the int gene of lambda are necessary for the integration of hybrid plasmids under conditions of effective int gene expression. If the level of Int protein synthesis is high enough, the prophage excision can be observed in the absence of Xis product. The six-fold decrease of Int protein concentration in the cell (in case of pInt lambda 2 as compared to pInt lambda 1) is critical both for integration and excision.

[Identification of partial hydrolysis products of lambda bacteriophage DNA by restriction endonuclease EcoRI]. / Identifikatsiia produktov nepolnogo gidroliza DNK bakteriofaga lambda endonukleazoi EcoR1.

The relationship between the electrophoretic mobility of double stranded DNA fragments electrophoresed in agarose gel and their molecular weights within the range from 1.10(6) to 8.10(7) daltons and agarose concentration 0.3--2.0% has been studied. Partial hydrolysis products of lambda phage DNA obtained by restriction endonuclease EcoRI have been separated. Partial hydrolysis products have been identified by determining the fragments of full cleavage as well as by genetic methods using a system of transformation of E. coli cells treated with CaCl2, which have been infected with different helper-phages containing definite gene mutations.

[Biological activity of different forms of bacteriophage lambda DNA]. / Biologicheskaia aktivnost' razlichiykh form DNK bakteriofaga lambda

Hershey circles and linear tandem aggregated forms of DNA have been obtained in vitro and treated with polynucleotide ligase to form phosphodiester bond. Using zone centrifugation in glycerol gradient covalently closed circles and linear dimers have been purified and their biological activity investigated. It was found that closed circular molecules lost most, if not all, of their activity in CaCl2-dependent system. In order to investigate the biological activity of tandem dimer molecules, hybrid dimers consisting of DNA's from lambda C1857 and lambda 1434 have been obtained. In plaque assay with the appropriate non-permissive strains of E. coli the efficiency of infectivity of hybrid dimers was measured. Biological activity of dimer molecules sealed with ligase was about 5% of the activity of linear monomers. Ig has been suggested that tandem dimers of lambda DNA joined by phosphodiester bond are able to penetrate into the CaCl2-treated host cells and both components of dimers are active during subsequent multiplication.

[Radiobiological method of studying the structure of the partially diploid area in T4 bacteriophage]. / Radiobiologicheskii metod izucheniie struktury chastichno diploidnoi oblasti u bacteriofaga T4.

The mechanism of cross-reactivation after UV-irradiation was examined using different deletion mutants as recipients. A model of the rescue mechanism of partly diploid area was suggested. The method of cross-reactivation in demonstrated to permit an easy determination of the orientation of duplicated genes.

[Lethal and mutagenic photodynamic effect of acridine orange on bacteriophage cd]. / Letal'noe i mutagennoe fotodinamicheskoe deistvie akridinovogo oranzhevogo na bakteriofag sd

Both acridine-sensitized inactivation and mutagenesis in phage sd have been studied and compared with the effect of other mutagens. Inactivation curve was not stictly exponential, with a small shoulder at short light doses and deviation of survival lower than 10(-5). The lethal effect was not reactivated by multiplicity reactivation. Photodynamic damage in phage sd was accompanied by the increase of the rise (but not of the latent) period in the one-step curve of phage multiplication and increase of the burst size. Experiments were carried out at dye concentration of 1-10(-5) M or lower; a strong dark effect of the dye being observed under 2-fold increase of the dye concentration. Plaque-type mutants were formed up to the maximum approximately 1% at the survival approximately 2--10(-5); in comparison with other mutagens photo-sensitized mutagenesis in phage sd was lower. The significant increase in the number of plaque mutants was observed after the illumination of phage fraction surviving the pre-treatment with higher acridine orange concentration (greater than or equal to 2-10(-5)M).