Bohl-Perron type stability theorems for linear difference equations with infinite delay

Relation between two properties of linear difference equations with infinite delay is investigated: (i) exponential stability, (ii) \l^p-input \l^q-state stability (sometimes is called Perron's property). The latter means that solutions of the non-homogeneous equation with zero initial data belong to \l^q when non-homogeneous terms are in \l^p. It is assumed that at each moment the prehistory (the sequence of preceding states) belongs to some weighted \l^r-space with an exponentially fading weight (the phase space). Our main result states that (i) $\Leftrightarrow$ (ii) whenever $(p,q) \neq (1,\infty)$ and a certain boundedness condition on coefficients is fulfilled. This condition is sharp and ensures that, to some extent, exponential and \l^p-input \l^q-state stabilities does not depend on the choice of a phase space and parameters $p$ and $q$, respectively. \l^1-input \l^\infty-state stability corresponds to uniform stability. We provide some evidence that similar criteria should not be expected for non-fading memory spaces.Comment: To be published in Journal of Difference Equations and Application

Exponential dichotomies of evolution operators in Banach spaces

This paper considers three dichotomy concepts (exponential dichotomy, uniform exponential dichotomy and strong exponential dichotomy) in the general context of non-invertible evolution operators in Banach spaces. Connections between these concepts are illustrated. Using the notion of Green function, we give necessary conditions and sufficient ones for strong exponential dichotomy. Some illustrative examples are presented to prove that the converse of some implication type theorems are not valid

Clinical and functional implications of kidney in patients with hepatic impairment

Departamentul Medicină Internă, Clinica Medicală nr. 1, Disciplina Sinteze clinice, Secţia nefrologie, IMSP SCM „Sfânta Treime" or. Chişinău, Al VI-lea Congres de Urologie, Dializă şi Transplant Renal din Republica Moldova cu participare internaţională (21-23 octombrie 2015)Rezumat Mecanismele care influenţează apariţia complicaţiilor renale la pacienţii cu ciroză hepatică sunt în continuare incomplet elucidate, determinând pronosticul nefavorabil al afecţiunii hepatice. Modificările de eliberare endogenă a prostaglandinelor renale, disfuncţia endotelială, semnificaţia lor în procesele complexe, prin care participă la modularea fluxului sanguin intrarenal la pacienţii cu afectare hepatică continuă să fie subiectul unor discuţii contradictorii. Subiectul cercetării prezentate a fost determinarea substanţelor vazoactive în serul sanguin la bolnavii cu ciroză hepatică clasa Child-Pugh A, B şi C, la pacienţii cu hipertensiune portală şi varice esofagiene (VE), ascită, encefalopatie hepatică (EH) şi în prezenţa factorilor de risc, care pot precipita complicaţiile renale şi analiza rezultatelor obţinute.Summary The mechanisms that influence renal complications in patients with liver cirrhosis remain incompletely understood, causing unfavorable prognosis of liver disease. Changes of endogenous prostaglandin renal release, endothelial dysfunction, their significance in modulating renal blood flow in patients with hepatic impairment continues to be the subject of contradictory discussions. The determination of these vazoactive agents in patients with liver cirrhosis Child-Pugh class A, B and C, in patients with portal hypertension and esophageal varices, in ascites, hepatic encephalopathy and the risk factors that can precipitate kidney complications, the evaluation of obtained results was the subject of the research

Update on type 2 cardiorenal syndrome

Department of Internal Medicine, Clinic of Cardiology, Clinic of Rheumatology and Nephrology, Nicolae Testemitsanu State University of Medicine and Pharmacy, Chisinau, the Republic of MoldovaBackground: Cardiorenal syndrome type 2 is an “umbrella” term used to describe clinical conditions in which chronic cardiac failure through a chronological and causal relationship leads to renal dysfunction. The syndrome is associated with a significant morbidity and mortality, that is why it has recently become a matter of growing debate related to pathogenesis, diagnosis, treatment effectiveness and safety. Our aim was to review epidemiological and pathological mechanisms underlying cardiorenal syndrome, to focus on up-to-date diagnosis and treatment strategies. We performed literature search in the Pubmed database in July 2015. The 1st key word used for search was “cardiorenal syndrome type 2”; and the 2nd key word was “cardiorenal syndrome in heart failure”. Conclusions: Over the last decade, a significant advance in the understanding of the cardiorenal syndrome has been achieved. However, precise pathways remain to be clarified. Clinical management of these patients include diuretics, vasodilatators, ultrafiltration, all these modalities promise more rapid volume removal, but their ultimate impact on survival and renal function is unknown. Future research is necessary to improve diagnosis, severity grading, to differentiate type 2 and type 4 cardiorenal syndrome and to determine efficient treatment strategies. Because of the syndrome’s complexity and poor outcome, it is important that cardiologists, nephrologists and internists work together for a unique goal – protecting the patient with cardiorenal syndrome

Instalarea complicaţiilor renale la pacienţii cu ciroze hepatice: aspecte fiziopatologice

Conferinţa naţională în medicina internă din Republica Moldova cu participare internaţională, 19-20 mai 2011, Chişinău, Republica MoldovaSummary. Vasoconstrictive effect of Endotelin-1 (ET- 1), the role of Prostaglandin E-2 (PGE-2) in regulation of renal blood flow were evaluated at 82 patients with liver cirrhosis. The results show the vasoconstrictive effect of ET-1 with it significantly increased level and the inhibited levels of PGE-2 in decompensated cirrhosis, that produce negative effects on renal blood flow.Actualitate. Perfuzia renală compromisă determină sensibilitatea rinichiului la modificările hemodinamice şi la intervenţia toxinelor, manifestându- se prin modificarea activităţii agenţilor vasoconstrictori şi vasodilatatori la nivelul circulaţiei renale. Elucidarea modificărilor de eliberare endogenă a prostaglandinelor renale şi contribuţia ET-1 la instalarea tulburărilor hemodinamicii renale la pacienţii cu ciroză hepatică necesită studii suplimentare. Scopul lucrării: estimarea valorilor serice ale PGE-2 şi ET-1 la pacienţii cu ciroză hepatică, cu scopul de a elabora scheme moderne de prevenire şi tratament medicamentos al perturbărilor funcţionale renale în ciroza hepatică. Materiale şi metode. Au fost luaţi în studiu 82 de pacienţi cu ciroză hepatică clasele Child-Pugh A, B, C (vârsta medie de 51,5±1,56 ani), inclusiv 12 pacienţi diagnosticaţi cu SHR. ET-1 şi PGE-2 în ser au fost determinate prin metoda imunoenzimatică ELISA. Rezultate. S-a constatat că valorile PGE-2, comparativ cu grupul de control, scad odată cu avansarea cirozei hepatice, când perfuzia renală este compromisă, efectul vasodilatator al PGE-2 se micşorează semnificativ. Scăderea ratei de filtraţie glomerulară se asociază cu creşterea valorii ET-1, cu hiponatriemia, scăderea răspunsului la diuretice şi instalarea edemelor refractare la tratament diuretic. Concluzii. Sinteza PGE-2 în rinichi este inhibată de perturbările hemodinamice renale odată cu avansarea cirozei hepatice, ceea ce se manifestă prin micşorarea valorilor PGE-2 în ser. Se constată creşterea valorilor ET-1 ca cel mai marcat vasoconstrictor cunoscut la pacienţii cu ciroză hepatică clasa Child–Pugh C. Scăderea ratei de filtrare glomerulară se asociază cu creşterea valorii ET-1, hiponatriemie, prezenţa edemelor refractare la pacienţii cu ascită marcată

Оценка патогенетических факторов, влияющих на почечные осложнения у больных циррозом печени

Catedra de Medicină Internă nr. 5, USMF „Nicolae Testemiţanu”, Conferinţa Ştiinţifico-Practică „Medicina modernă, actualităţi şi perspective”, consacrată aniversării de 40 de ani ai Spitalului Clinic al Ministerului Sănătăţii, 27-28 mai, 2010, Chişinău, Republica MoldovaThe study involved 82 patients - 40 women and 42 men. Early detection of renal function impairment is a major predictive importance in managing patients with liver cirrhosis. In liver cirrhosis Child-Pugh class C, the renal hemodynamics is already compromised and is characterized by growth of vasoconstrictor factors. Azotemia in acute renal failure in hepato-renal syndrome does not reach very high values and is not associated with severe hyperpotassemia. PGE2 synthesis in the kidney is progressively inhibited by renal hemodynamic disturbances with advancing liver cirrhosis, which translates into decreasing PGE-1 levels in the serum. E1 is the vasoconstrictor with the most increased levels in patients with liver cirrhosis Child-Pugh class C and particularly in patients with hepato-renal syndrome. The decreased glomerular filtration rate is associated with an increased amount of ET-1, low sodium in the blood and edema in patients with refractory ascites. В исследовании включены 82 больных - 40 женщин и 42 мужчины. Раннее обнаружение почечной недостаточности является одним из основных прогностических факторов в менеджменте больных циррозом печени. При циррозе печени класса C по ChildPugh почечная гемодинамика уже скомпрометирована и характеризуется ростом сосудосуживающих факторов при отсутствии роста показателей эндогенных креатинина и мочевины в сыворотке крови. Азотемия в острой почечной недостаточности при печеночнопочечном синдроме не достигает больших значений и не связана с выраженной гиперкалиемией. Синтез PGE2 в почках постепенно замедляется из-за нарушения почечной гемодинамики при прогрессировании цирроза печени. У больных циррозом печени класса С по Child-Pugh, особенно при наличии печеночно-почечного синдрома, выявляется повышенная концентрация сосудосуживающего фактора Е1. Снижение скорости клубочковой фильтрации ассоциируется с повышенным содержанием ЕТ-1, низким содержанием натрия крови и с отеками

Carbon dynamics, net primary productivity (NPP) and human appropriated NPP (HANPP) across a forest‐cocoa farm landscape in West Africa

Terrestrial net primary productivity (NPP) is an important metric of ecosystem functioning; however, there is little empirical data on the NPP of human-modified ecosystems, particularly smallholder,perennial crops like cocoa (Theobroma cacao), which are extensive across the tropics. Human appropriated NPP (HANPP) is a measure of the proportion of a natural system’s NPP that has either been reduced through land-use change or harvested directly and, previously, has been calculated to estimate the scale of the human impact on the biosphere. Additionally, human-modification can create shifts in NPP allocation and decomposition, with concomitant impacts on the carbon cycle. This study presents the results of three years of intensive monitoring of forest and smallholder cocoa farms across disturbance, management intensity, distance from forest and farm age gradients. We measured among the highest reported NPP values in tropical forest, 17.57 ± 2.1 and 17.7 ± 1.6 Mg C ha-1 yr-1 for intact and logged forest respectively; however, the average NPP of cocoa farms was still higher, 18.8 ± 2.5 Mg C ha-1 yr-1, which we found was driven by cocoa pod production. We found a dramatic shift in litterfall residence times, where cocoa leaves decomposed more slowly than forest leaves and shade tree litterfall decomposed considerably faster, indicating significant changes in rates of nutrient cycling. The average HANPP value for all cocoa farms was 2.1 ± 1.1 Mg C ha-1 yr-1; however, depending on the density of shade trees it ranged from -4.6 to 5.2 Mg C ha-1 yr-1. Therefore, rather than being related to cocoa yield, HANPP was reduced by maintaining higher shade levels. Across our monitored farms 18.9% of farm NPP was harvested (i.e. whole cocoa pods) and only 1.1% (i.e.cocoa beans) was removed from the system; suggesting that the scale of HANPP in smallholder cocoa agroforestry systems is relatively small

Исследование влияния рамиприла и эпросартана на диастолическую дисфункцию, функциональный класс сердечной недостаточности и инсулинорезистентность при длительном лечении гипертензивной болезни

IMSP Institutul de Cardiologie, IMSP Spitalul Clinic Republican Timofei Moșneaga, IP USMF Nicolae Testemițanu, Spitalul Clinic de Recuperare Iași, RomâniaHipertensiunea arterială (HTA) și insulinorezistența (IR) coexistă frecvent ca niște condiții-satelit, agravând evoluția sindromului metabolic. Prezența disfuncției diastolice (DD) a ventriculului stâng (VS) categorizează pacienții hipertensivi ca având un risc cardiovascular înalt, indiferent de masa ventriculară sau nivelul TA. Unele studii care au vizat pacienții cu IR au evidențiat și compromiterea funcției diastolice a VS, iar gradul alterării acesteia ar fi dependent de nivelul perturbărilor metabolismului carbohidraților. Luând în considerare rolul activării neurohumorale în dezvoltarea și perpetuarea HTA ce duce la afectarea organului-țintă și insufi ciență cardiacă (IC), precum și interrelația cu IR, am considerat necesară evaluarea acțiunii terapiei convenționale active asupra sistemului renină-angiotensină-aldosteron (SRAA) și a impactului acesteia asupra funcției diastolice, clasei funcționale NYHA a IC și IR. Studiul a demonstrat o efi ciență comparabilă a IEC ramipril și ARA II eprosartan în restaurarea indicilor fi ziologici lusitropici, ameliorarea clasei funcționale NYHA a IC și a indicilor metabolismului carbohidraților (HOMAIR), dar cu o superioritate statistic semnifi cativă la administrarea ARA II eprosartan, fenomen explicat prin efectele simpatolitice adiționale, specifi ce moleculei de eprosartan.Hypertension and insulin resistance (IR) that oft en coexist satellite conditions aggravating the evolution of metabolic syndrome. Association of HT and insulin resistance (IR) are related to higher cardio metabolic risk and enhancement of target organ damages (TOD). Studies focused on patients with IR revealed compromised diastolic function and the alteration’s degree would be dependent on carbohydrate metabolism disturbances. Considering the key-role of the neurohumoral activation in pathophysiology of both heart failure and IR, we have considered the assessment of conventional therapy acting on the renin-angiotensin-aldosterone system (RAAS) and its impact on diastolic function, NYHA functional class of heart failure and IR. The study demonstrated a comparable efficacy of both ACEI Ramipril and ARB Eprosartan on restoration of physiological indices of lusitropy, improvement of functional class of heart failure and carbohydrate metabolism indices (HOMAIR), but with greater efficiency in the Eprosartanmedicated arm, probably due to additional sympatholytic effect of its moiety.Эссенциальная гипертензия и инсулинорезистентность часто сосуществуют и усугубляют течение метаболического синдрома. Наличие диастолической дисфункции левого желудочка автоматически переводят человека в группу высокого сердечно-сосудистого риска, независимо от уровня артериального давления и массы миокарда левого желудочка. Некоторые исследования, которые включали пациентов с инсулинорезистентностью, выявили нарушения диастолической функции, и степень этих нарушений коррелировала с тяжестью пертурбаций углеводного обмена. Принимая во внимание важность нейрогуморальной активации в развитии поражений органов-мишени, сердечной недостаточности и взаимосвязи с инсулинорезистентностью, мы исследовали эффективность терапии, влияющей на ренин-ангиотензин-альдостероновую систему (РААС), на показатели диастолической функции, функциональный класс сердечной недостаточности и инсулинорезистентность. Исследование доказало сравнимую эффективность ИАПФ рамиприла и АРА II эпросартана на восстановление физиологических показателей диастолической функции, улучшение функционального класса NYHA сердечной недостаточности и инсулинорезистентности. В то же время, было установлено статистически достоверное превосходство эпросартана и улучшение вышеперечисленных показателей в сравнение с рамиприлом, что объясняется дополнительным симпатолитическими эффектами молекулы эпросартана

Proximity to forest mediates trade-offs between yields and biodiversity of birds in oil palm smallholdings

There is much debate about how best to mitigate the effects of agricultural expansion on biodiversity, especially in the tropics. Recent studies have emphasized that proximity to natural habitats can enhance farmland biodiversity, yet few studies have examined whether or not such proximity mediates local trade-offs between yields and biodiversity, and hence alters conclusions about the ecological benefits of alternative farming strategies. Here we examine yield-biodiversity trade-offs, focusing on birds in oil palm smallholdings at different distances from remaining areas of forest, including a large forest reserve, in Ghana. We found significantly fewer birds on higher-yielding than lower-yielding farms, in terms of both species richness and abundance. For forest specialist birds (likely to be highly vulnerable to conversion of land to agriculture) we also found a greater trade-off (i.e., lower richness and abundance for a given yield) at farms further from forest, to the extent that increasing distance to the nearest forest from 1 to 10 km had a similar effect as a 3- to 5-fold increase in fruit yield brought about by increased intensification. Our study highlights the importance of accounting for the effects of natural forest in the landscape when considering agricultural policies for biodiversity protection, underlining the importance of a landscape-scale approach to conservation

Chlamydophila pneumoniae induces expression of Toll-like Receptor 4 and release of TNF-α and MIP-2 via an NF-κB pathway in rat type II pneumocytes

BACKGROUND: The role of alveolar type II cells in the regulation of innate and adaptive immunity is unclear. Toll-like receptors (TLRs) have been implicated in host defense. The purpose of the present study was to investigate whether Chlamydophila pneumoniae (I) alters the expression of TLR2 and/orTLR4 in type II cells in a (II) Rho-GTPase- and (III) NF-κB-dependent pathway, subsequently (IV) leading to the production of (IV) pro-inflammatory TNF-α and MIP-2. METHODS: Isolated rat type II pneumocytes were incubated with C. pneumoniae after pre-treatment with calcium chelator BAPTA-AM, inhibitors of NF-κB (parthenolide, SN50) or with a specific inhibitor of the Rho-GTPase (mevastatin). TLR2 and TLR4 mRNA expressions were analyzed by PCR. Activation of TLR4, Rac1, RhoA protein and NF-κB was determined by Western blotting and confocal laser scan microscopy (CLSM) and TNF-α and MIP-2 release by ELISA. RESULTS: Type II cells constitutively expressed TLR4 and TLR2 mRNA. A prominent induction of TLR4 but not TLR2 mRNA was detected after 2 hours of incubation with C. pneumoniae. The TLR4 protein expression reached a peak at 30 min, began to decrease within 1–2 hours and peaked again at 3 hours. Incubation of cells with heat-inactivated bacteria (56°C for 30 min) significantly reduced the TLR4 expression. Treated bacteria with polymyxin B (2 μg/ml) did not alter TLR4 expression. C. pneumoniae-induced NF-κB activity was blocked by TLR4 blocking antibodies. TLR4 mRNA and protein expression were inhibited in the presence of BAPTA-AM, SN50 or parthenolide. TNF-α and MIP-2 release was increased in type II cells in response to C. pneumoniae, whereas BAPTA-AM, SN50 or parthenolide decreased the C. pneumoniae-induced TNF-α and MIP-2 release. Mevastatin inhibited C. pneumoniae-mediated Rac1, RhoA and TLR4 expression. CONCLUSION: The TLR4 protein expression in rat type II cells is likely to be mediated by a heat-sensitive C. pneumoniae protein that induces a fast Ca(2+)-mediated NF-κB activity, necessary for maintenance of TLR4 expression and TNF-α and MIP-2 release through possibly Rac and Rho protein-dependent mechanism. These results indicate that type II pneumocytes play an important role in the innate pulmonary immune system and in inflammatory response mechanism of the alveolus