Identification of two-neuron FitzHugh-Nagumo model based on the speed-gradient and filtering.

The paper is devoted to the parameter identification problem for two-neuron FitzHugh-Nagumo models under condition when only one variable, namely, the membrane potential, is measured. Another practical assumption is that both variable derivatives cannot be measured. Finally, it is assumed that the sensor measuring the membrane potential is imprecise, and all measurements have some unknown scaling factor. These circumstances bring additional difficulties to the parameters' estimation problem, and therefore, such case was not studied before. To solve the problem first, the model is transformed to a more simple form without unmeasurable variables. Variables obtained from applying a second-order real filter-differentiator are used instead of unmeasurable derivatives. Then, an adaptive system, parameters of which are estimates of original system parameters, is designed. The estimation (identification) goal is to properly adjust parameter estimates. To this end, the speed-gradient method is employed. The correctness of the obtained solution is proved theoretically and illustrated by computer simulation in the Simulink environment. The sufficient conditions of asymptotically correct identification for the speed-gradient method with integral objective function are formulated and proved. The novelty of the paper is that in contrast to existing solutions to the FitzHugh-Nagumo identification problem, we take into account a systematic error of the membrane potential measurement. Furthermore, the parameters are estimated for a system composed of two FitzHugh-Nagumo models, which open perspectives for using the proposed results for modeling and estimation of parameters for neuron population.

[Cytomorphometric study on the effect of smoking on tissues adjacent to dental implants]. / Vliianie kureniia na sostoianie tkanei, prilezhashchikh k dental'nym implantatam, po dannym tsitomorfometricheskogo issledovaniia.

The aim of the study was determination of the effectiveness of peri-implantation zone tissues control by means of cytomorphometry in cellular imprints obtained from the area of dental implantation on a model applying a comparison of the state of the tissues of the peri-implantation zone of smokers and non-smokers. MATERIAL AND METHODS: Cytomorphometry was used for tissue monitoring in implant-adjacent areas by the Index of Destruction (ID) and the Inflammatory-Destructive Index (IDI) in the group of smoking patients: 6 females and 9 males (41 implant) and in the group of non-smoking patients: 13 females and 14 males (97 implants). Follow-up terms in both groups from the moment of gingival former or provisional crown placement comprised 1, 5, 15, 25, 30, 60, 120, 180, 240, 720 days. Significant increase of ID within 25-120 days was revealed in smokers. The study of Inflammation-Distraction Indices revealed a statistically significant increase in the values in group of smokers at 5 to 60 days. The results of using of cytomorphometric method allow conclude that smoking is a pathogenic factor that exerts its influence through initiation and sustentation of an inflammatory process in the tissues adjacent to dental implants.

[Development of disease-specific patient groups within Pro Retina]. / Entwicklung diagnosespezifischer Gruppen in der Pro Retina.

The formation, development and external impact of the following eight disease-specific patient groups with rare forms of retinal degeneration (RRD) within the patient organization Pro Retina are described: Gyrate Atrophy, Bardet-Biedl Syndrome (BBS), Adult Refsum's Disease, Usher Syndrome, Rod-Cone Dystrophy, Leber's Congenital Amaurosis, Choroideremia and Stargardt Disease/juvenile macular degeneration. Within the project sponsored by the German Ministry of Health (BMG) approaches of patient self-help for an adequate organization and interaction with the professional medical care system were supported, analyzed and documented. In syndromic RRD a relatively high proportion of patients are organized in patient groups (Refsum's disease 25%, BBS 14%, Usher Syndrome 8%). Patients with syndromic RRD are more highly motivated to contribute to self-help work than patients with non-syndromic RRD. At the same time, these patients are more dependent on the support from their relatives and on technical aids. The following tendencies in the development of RRD groups were observed: increasing focus on one patient organization (PRO RETINA Deutschland, Self-Help Organisation of People with Retinal Degenerations) all RRD groups in Pro Retina grew; RRD groups became increasingly independent within Pro Retina; external activities of the groups showed considerable increase. Stable work relationships with scientific and medical care institutions have been established. The example of RRD demonstrates how rare and isolated patients receive basic coping support by self-help groups, how they deal with resources in a collective way and how they can interact with the medical care system.

[The peculiarities of the central haemodynamics and its oscillations in individuals with different level of blood volume of chest organs].

The indexes of central haemodynamics, oscillations power of the struck blood volume and R-R interval duration in different frequency ranges as well as the levels of blood filling of chest organs were measured in 143 healthy young men at rest and during tilt test. Based on the formation of different levels of blood filling of chest organs, two strategies ofhaemodynamics adapting changes were found in healthy men. The high level of blood filling of chest organs is characterized by the higher level of heart throw, which results in an increase in the average arterial pressure. The increase of the general peripheral vessel resistance and rather low level of heart throw was typical for the low level of blood filling of the chest organs. Individuals with middle level of blood filling of chest organs were found to have more essential strain regulatory mechanisms than individuals of the edge groups according to the parameters of the struck blood volume oscillations and the R-R intervals duration at rest and during tilt test.

[Patient participation in medical care, taking rare retinal degenerations as examples]. / Patientenselbsthilfe und seltene Erkrankungen. Mitgestaltung der Versorgungsrealität am Beispiel seltener Netzhautdegenerationen.

Eight rare retinal degenerations were chosen to exemplify self-organisation and involvement of patient self-help groups in medical care. They were studied and supported in their development on the following levels: disease-specific groups (level 1), patient organisations (level 2), umbrella organisation (level 3). Databases of defined needs and concerns ("Themenspeicher") of disease-specific patient groups and of patient organisations with respect to care, research and patient networking were established. Priority concerns were implemented in the following areas: specialised medical care; quality assurance; quality management; expert panel with international dialogue of patients and physicians (including consensus statement on treatment recommendations); glossary internet portal; criteria for patient-oriented disease descriptions; structured documentation of patient experiences; patient management of health care records (paper bound and electronic health records). Apart from disease- specific approaches, interdisciplinary disease approaches were also applied, e.g. by contributing to the establishment of the German Alliance for Rare Diseases (ACHSE). This umbrella organisation has substantially improved chances for cooperation and patient advocacy. Patient participation was promoted by a federal regulation in 2004 ("Patientenbeteiligungsverordnung"). The example of rare retinal degenerations demonstrates the advantage of strong patient and umbrella organisations. Further development of qualified self-help resources is required for patient participation in rare diseases.

Genetic counseling in carriers of reciprocal chromosomal translocations involving long arm of chromosome 16.

Families with balanced chromosomal changes ascertained by unbalanced progeny, miscarriages, or by chance are interested in their probability for unbalanced offspring and other unfavorable pregnancy outcomes. This is usually done based on the original data published by Stengel-Rutkowski et al. several decades ago. That data set has never been updated. It is particularly true for the subgroup with low number of observations, to which belong reciprocal chromosomal translocations (RCTs) with breakpoint in an interstitial segment of 16q. The 11 pedigrees from original data together with the new 18 pedigrees of RCT carriers at risk of single-segment imbalance detected among 100 pedigrees of RCT carriers with breakpoint position at 16q were used for re-evaluation of the probability estimation for unbalanced offspring at birth and at second trimester of prenatal diagnosis, published in 1988. The new probability rate for unbalanced offspring after 2 : 2 disjunction and adjacent-1 segregation for the total group of pedigrees was 4 +/- 3.9% (1/25). In addition, the probability estimate for unbalanced fetuses at second trimester of prenatal diagnosis was calculated as 2/11, i.e. 18.2 +/- 11.6%. The probability rates for miscarriages and stillbirths/early deaths were about 16 +/- 7.3% (4/25) and <2% (0/25), respectively. Considering different segment lengths of 16q, higher probability rate (0/8, i.e. <6.1%) for maternal RCT carriers at risk of distal 16q segment imbalance (shorter segment) was obtained in comparison with the rate (0/10, i.e. <4.8%) for RCT at risk of proximal segment imbalance (longer segment). It supports findings obtained from the original data for RCT with other chromosomes, where the probability for unbalanced offspring generally increased with decreasing length of the segments involved in RCT. Our results were applied for five new families with RCT involving 16q, namely three at risk of single-segment imbalance [t(8;16)(q24.3;q22)GTG, ish(wcp8+,wcp16+;wcp8-,wcp16+), t(11;16)(q25;q22)GTG, and t(11;16)(q25;q13)GTG] and two with RCT at risk of double-segment imbalance [t(16;19)(q13;q13.3)GTG, isht(16;19)(q13;q13.3) (D16Z3+,16QTEL013-D19S238E+,TEL19pR-; D16Z3-, D19S238E-,TEL19pR+), and t(16;20)(q11.1;q12)GTG, m ish,t(16;20)(wcp16+,wcp20+;wcp16+,wcp20+)]. They have been presented in details to illustrate how the available empiric data could be used in practice for genetic counseling.

[Fast direct method of obtaining metaphase and prometaphase chromosomes from chorion biopsy cells and human embryos during the lst semester of pregnancy]. / Uskorennyi priamoi metod polucheniia metafaznykh i prometafaznykh khromosom iz kletok bioptata khoriona i émbrionov cheloveka v pervom trimestre beremennosti.

Samples of chorionic villi and embryonic tissues (brain, brain--sheaths) are thoroughly washed with Hank's solution, immediately subjected to hypotonic treatment (0.9% sodium citrate plus few drops of 0.01% colchicine) 37 degrees C, 30 min, prefixed 20 min with equal amount of standard fixative mixture, twice fixed in standard fixative solution (1 hour, -10 degrees C), hydrated with equal volume of distilled water (5-10 min), dried, macerated directly on the slide with 60% acetic acid. The cell suspension is then evenly spread on the slide surface, dried, postfixed and stained. The method provides sufficient amount of metaphase and prometaphase mitotic plates suitable for differentiating staining in 1.5-2 hours after sampling and might be recommended for routine chromosomal analysis in prenatal diagnosis of inherited diseases during early pregnancy.