Putative role of Brugada syndrome genes in familial atrial fibrillation.

OBJECTIVE: Familial atrial fibrillation (FAF), a not uncommon arrhythmia of the atrium, is characterized by heritability, early onset and absence of other heart defects. The molecular and genetic basis is still not completely clear and genetic diagnosis cannot be achieved in about 90% of patients. In this study, we present the results of genetic screening by next generation sequencing in affected Russian families. PATIENTS AND METHODS: Sixty subjects (18 probands and 42 relatives) with a clinical diagnosis of FAF were enrolled in the study. Since AF frequently associates with other cardiomyopathies, we included all genes that were known to be associated with these disorders at the time of our study. All probands were therefore systematically screened for 47 genes selected from the literature. RESULTS: Our study revealed that seven variants co-segregated with the clinical phenotype in seven families. Interestingly, four out of six genes and three out of seven variants have already been associated with Brugada syndrome in the literature. CONCLUSIONS: To our knowledge, this is the first report of association of the CACNA1C, CTNNA3, PKP2, ANK2 and SCN10A genes with FAF; it is also the first study in Russian families.

[Frequency and risk factors for the development of infravesical obstructions caused by surgery of benign prostatic hyperplasia].

Benign prostatic hyperplasia (BPH) is one of the most common diseases of men elderly and senile age. The main surgical methods of treatment for BPH are transurethral resection and open prostatectomy. In some cases surgical treatment of BPH is accompanied by the development of postoperative complications leading to recurrence of the infravesical obstruction. Currently, there are no strict guidelines for selection of an optimal method of correction of late obstructive complications. This study highlights the main existing theories concerning development of urethral strictures and bladder neck contracture.

[Short- and long-term potentiation in the afferent pathways of the hippocampus in the newborn rabbit]. / Kratkovremennaia i dlitel'naia potentsiatsiia v afferentnykh putiakh gippokampa novorozhdennykh krolikov.

Field potentials were recorded from dendritic and cell body layers of CA1 and dentate regions in newborn rabbits. Responses were evoked by electrical stimulation of the collateral Schaffer system and the perforant path with paired (a 15-100 ms interstimulus interval) and rhythmical stimuli (20-40/c, 3-5 s). Short-term potentiation in the tests with paired stimulation and posttetanic potentiation (up to 3 h) were observed in the CA1 area beginning from the first postnatal day and in the later maturing fascia dentata beginning from 8-10th days, i.e. when neuronal reactions to stimulation of the appropriate afferent pathways first appeared.

[Functional maturation of the mossy synapses of hippocampal fibers during rabbit ontogeny]. / Funktsional 'noe sozrevanie sinapsov mshistykh volokon gippokampa v ontogeneze krolika.

The time course of functional maturation of the mossy fibre synapses in the pyramidal cells of the dorsal hippocampus CA3-CA4 areas was investigated in intact, drug-free 1-14-day old rabbits by the method of extracellular recording of focal potentials and unit responses to electrical stimulation of the fascia dentata. Focal potentials as a biphasic short latency wave, spike discharges with latency from 3 to 10 ms and inhibitory reactions of the hippocampal units appeared in response to a single shock on the 4th postnatal day. During the following ten days the amplitude of the focal potentials increased from several hundred microvolts to several millivolts. The most dramatic increase occurred between the 4th and the 7th days. Posttetanic potentiation of the responses was observed already from the 4th postnatal day.

[Frequency potentiation in newborn rabbit hippocampus]. / Chastotnaia potentsiatsiia v gippokampe novorozhdennykh krolikov.

Ontogenetic development of the frequency potentiation in the entorhinal afferent input of the hippocampus was studied on unanesthetized rabbits 1--15 days after birth. In the fields CA1 and CA3 of the new-born rabbits rhythmical electrical stimulation (1--20 Hz) of the perforant path led to a 20--100% increase in the amplitude of local potentials as compared to the control value and to an increase in the probability of the mass discharge response from 0--0.5 (in control) to 0.8--1.0 (during tetanization). In 1--3-day-old rabbits the potentiation was especially pronounced at frequencies of 4--6 Hz. The frequency optimum of 4--15 Hz appeared on the fifth day after birth. The frequency potentiation of the mass discharge was observed on the 8th--10th day of life. The results show that the frequency potentiation in the cortical afferent connections of the hippocampus can be recorded already in new-born rabbits and achieved the mature pattern at the beginning of the second week of the postnatal life.

[Electrophysiologic study of the functional characteristics of cortical input into the hippocampus of newborn rabbits]. / Elektrofiziologicheskoe issledovanie funktsional'nykh osobennostei korkovogo vkhoda v gippokamp u novorozhdennykh krolikov.

Functional maturation of perforant pathway synapses on neurones of the dorsal hippocampus and fascia dentata was examined in unanaesthetized rabbits 1 to 25 days of age, by means of extracellular recording of fiold potentials and of neuronal responses to electrical stimulation of the cortical afferent input. In the areas CA1 and CA3 of the dorsal hippocampus, field potentials, activating and inhibitory neuronal responses to stimulation of the perforant pathway with single impulses were recorded from the first day of the postnatal life, while short-latency responses of the fascia dentata were revealed later--at the end of the first week or the beginning of the second week of life. The data obtained suggest that in rabbits, the synapses of the perforant pathway are functioning from the first days after birth. The postnatal development of the cortical afferent input to the hippocampus is related to the maturation of the dentate gyrus.

[Effect of sectioning cortico-hippocampal connections on the impulse activity of dorsal hippocampal neurons]. / Vliianie pererezki korkovo-gippokampal'nykh sviazei na impul'snuiu aktivnost' neironov dorzal'nogo gippokampa

Characteristics of spontaneous and evoked neuronal activity in the fields CA1 and CA3 of the dorsal hippocampus were studied on alert rabbits aged from 30 to 40 days, intact and with an undercutting of the entorhinal cortex (EC) on the 15th to 20th day. The nature of neuronal reactivity depends on the pattern of spontaneous spike activity (three types of cells). Elimination of the afferent input from the EC leads to a sharp drop in the field CA3 of the spontaneous activity of II type neurones with spike complexes achieving inhibitory reactions and, accordingly, to the absence of these reactions. The frequency of background activity of I and III type neurones, which give activating responses, increases. At the same time their reactivity and duration of feactions to indifferent acoustic stimuli increase, especially in the field CA3. The number of phasic and forming responses diminishes. The data obtained attest that the elimination of the cortical input disturbs the capacity of hippocampal neurones to form adequate reactions to indifferent stimuli, which may be due to reduced lability in the system of the orienting reflex owing to a deficit of inhibitory mechanisms.