Pathophysiological mechanisms underlying the development of renal dysfunction and progression of congestive heart failure (CHF) remain poorly understood. Recent studies have revealed striking differences in the rol e of epoxyeicosatrienoic acids (EETs), active products of cytochrome P-450-dependent epoxygenase pathway of arachidonic acid, in the progression of aorto-caval fistula (ACF)-induced CHF between hypertensive Ren-2 renin transgenic rats (TGR) and transgene-negative normotensive Hannover Sprague-Dawley (HanSD) controls. Both ACF TGR and ACF HanSD strains exhibited marked intrarenal EETs deficiency and impairment of renal function, and in both strains chronic pharmacologic inhibition of s oluble epoxide hydrola se (sEH) (which normally degrades EETs) normalized EETs levels. However, the treatment improved the survival rate and attenuated renal function impairment in ACF TGR only. Here we aimed to establish if the reported improved renal function and attenuation o f progression of CHF in ACF TGR observed after sEH blockade depends on increased vasodilatory responsiveness of renal resistance arteries to EETs. Therefore, we examined the responses of interlobar arteries from kidneys of ACF TGR and ACF HanSD rats to EET-A, a new stable 14,15-EET analog. We found that the arteries from ACF HanSD kidneys rats exhibited greater vasodilator responses when compared to the ACF TGR arteries. Hence, reduced renal vasodilatory responsiveness cannot be responsible for the lack of beneficial effects of chronic sEH inhibition on the development of renal dysfunction and progression of CHF in ACF HanSD rats., A. Sporková, Z. Husková, P. Škaroupková, N. Rami Reddy, J. R. Falck, J. Sadowski, L. Červenka., and Obsahuje bibliografii
Previous studies have substantiated the antipyretic role played by extrahypothalamic limbic system (EXHY-LS) AVP during fever. Repeated attempts to elucidate other thermoregulatory functions of this hormone have failed. Circumstantial evidence, however, suggest central role for this hormone in thermoregulation under hypohydration. Hypohydration, hyperosmolarity and hypovolaemia induce upward shifts in temperature thresholds for activation of heat dissipating mechanisms. When hypovolaemia is superimposed on hyperosmolarity these shifts are additive. Analogously, these two stressors when combined, decrease the osmotic threshold for AVP release. In rats, the elevated temperature thresholds for evaporative cooling and peripheral vasodilation occurring with hypohydration are positively correlated with lower Hypothalamic/EXHY-LS AVP ratio. Reciprocal relations between limbic system and blood AVP contents suggest competitive interaction between central and peripheral demands. Hypothesis for the possible mode of action of central AVP in thermoregulation under hypohydration is discussed.
The potassium channel opening drug, pinacidil, has been examined in isolated perfused lungs taken from rats with hypoxic pulmonary hypertension (housed in 10 % oxygen for 7 days) and control rats. Inhibition by pinacidil (1 to 30 //M) of noradrenaline (NA)-induced vasoconstriction (NA infusions; /^-adrenoceptors blocked) and of hypoxic pulmonary vasoconstriction (HPV; ventilation for 3.5 -4.5 min with 0-1 % oxygen) were compared. The vasoconstrictor responses in preparations from control and hypoxic rats, respectively, were (mm Hg) NA 6.6±0.68 (6); 8.2±1.45 (9); HPV 7.8±1.03 (12); 8.8±0.93 (13). These responses were reversibly inhibited by pinacidil. In lungs from control rats pinacidil was 10-fold less potent against NA than against HPV, but in lungs from hypoxic rats it was equipotent against NA and HPV. When tested against NA, but not HPV, pinacidil was significantly more potent in lungs from hypoxic rats than control rats. It is postulated that NA-induced vasoconstriction in lungs from hypoxic rats, and HPV in both groups of rats, involve calcium influx through voltage-operated calcium channels. Consequently, these responses are readily inhibited by drugs such as pinacidil which open potassium channels and hyperpolarise the cell membrane. In contrast in lungs from control rats, NA-induced constriction may involve mainly intracellular calcium release and thus be less readily inhibited by the hyperpolarising effect of pinacidil.
The aim of this study was to test the hypothesis that vasorelaxing action of vasonatrin peptide (VNP) is due to activation of the large-conductance Ca2+-activated potassium channel (BKCa) via guanylyl cyclase (GC)-coupled natriuretic peptide receptors (NPRs) in vascular smooth muscle cells (VSMCs). Contraction experiments were performed using human radial artery, whereas BKCa current by patch clamp was recorded in cells from rat mesenteric artery. Contractility of rings cut from human radial artery was detected in vitro. As a result, VNP induced a dose-dependent vasorelaxation of human radial artery, which could be mimicked by 8-Br-cGMP, and suppressed by TEA, a blocker of BKCa, HS-142-1, a blocker of GC-coupled NPRs, or methylene blue (MB), a selective inhibitor of guanylyl cyclase. Sequentially, whole-cell K+ currents were recorded using patch clamp techniques. BKCa current of VSMCs isolated from rat mesentery artery was obtained by subtracting the whole cell currents after applications of 10-7 mol/l iberiotoxin (IBX) from before its applications. In accordance with the results of arterial tension detection, BKCa current was significantly magnified by VNP, which could also be mimicked by 8-Br-cGMP, whereas suppressed by HS-142-1, or MB. Taken together, VNP acts as a potent vasodilator, and NPRA/B-cGMP-BKCa is one possible signaling system involved in VNP induced relaxation., J. Yu ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
A brief nomenclatural history of Vavraia culicis (Weiser, 1947), the type species for the genus Vavraia Weiser, 1977, is presented together with a detailed description of the cytological and ultrastructural characteristics of a Vavraia culicis-like microsporidian species isolated from Aedes albopictus (Scuse) in Florida. This ''Florida isolate'', is the only known isolate of a species of the genus Vavraia from mosquitoes propagated in laboratory culture. Although the Florida isolate has been used under the name Vavraia culicis in several molecular phylogeny and host-parasite studies, it has not been structurally characterized and its relationship to the type species Vavraia culicis has never been examined. Structural data strongly support placement of the Florida isolate within the genus Vavraia and indicate its close relationship to both the type species of the genus and to other Vavraia-like mosquito microsporidia to which the name V. culicis has been applied. However, the identity of the Florida isolate with V. culicis (Weiser, 1947) Weiser, 1977 cannot be presently confirmed. Morphometric examination of spores of several Vavraia-like microsporidia isolates from mosquitoes, including the type material of Vavraia culicis, indicates that Vavraia culicis-like microsporidia probably represent not a single species, but a group of closely related organisms. Subspecies status is proposed for the Florida isolate.
Vazospazmy jsou považovány za hlavní příčinu vysoké mortality a špatné prognózy pacientů se subarachnoidálním krvácením způsobeným rupturou aneuryzmatu. Námi popisovaná kazuistika se týká 30leté pacientky, která byla přijata s Glasgow Coma Scale 14 a těžkou levostrannou hemiparézou. Počítačová tomografie odhalila subarachnoidální krvácení. Jeho příčinou byla ruptura aneuryzmatu na arteria cerebri media vpravo. Aneuryzma bylo zaklipováno. Pro symptomatické vazospazmy jsme opakovaně provedli mechanickou i farmakologickou angioplastiku. Přesto došlo k rozvoji ischemie v pravé mozkové hemisféře, což nás vedlo k dekompresivní kraniektomii. Finálně vazospazmy regredovaly a nastala úplná úprava neurologického deficitu. Čtyři roky po operaci je pacientka plně soběstačná, bez poruchy hybnosti končetin, s nedotčenými kognitivními funkcemi., Vasospasms are considered to be the major cause of high mortality and bad prognosis in patients with subarachnoid hemorrhage caused by a rupture of an aneurysm. Our case report describes a 30-year-old patient admitted with Glasgow Coma Scale 14 and severe left-sided hemiparesis. Computed tomography revealed subarachnoid hemorrhage. Its etiology was ruptured aneurysm of the right middle cerebral artery. The aneurysm was clipped. Mechanical and pharmacological angioplasty was repeatedly performed to manage symptomatic vasospasms. Despite these interventions, an ischemic lesion developed in the right brain hemisphere that prompted us to perform decompressive craniectomy. Finally, vasospasms, as well as the neurological deficit, disappeared. Four years after the surgery, the patient is independent, without any limb movement disorder and with normal cognitive functions., and L. Jurák, P. Buchvald, V. Beneš, III., M. Kaiser, P. Suchomel
Nedávné studie ukázaly, že prevalence familiární hypercholesterolemie (FH) je přibližně dvojnásobná oproti dřívějším předpokladům a onemocnění tak postihuje přibližně jednoho z 250 jedinců obecné populace. Jedná se tedy o nejčastější vrozené metabolické onemocnění vůbec. V důsledku geneticky podmíněné poruchy v metabolizmu LDL-cholesterolu dochází k jeho hromadění v cirkulaci a ve tkáních, což vede předčasnému rozvoji aterosklerózy. Neléčení jedinci mohou mít infarkt myokardu ve 3. nebo 4. dekádě života, až v jedné třetině případů s fatálním koncem. Onemocnění je celosvětově nedostatečně diagnostikováno a léčeno. V České republice běží již od roku 1998 projekt MedPed, který se soustředí na včasnou diagnostiku FH s cílem zahájit léčbu co nejdříve, a snížit tak u postižených jedinců riziko předčasné klinické manifestace ischemické choroby srdeční a předčasného úmrtí. Důležitým bodem projektu je kaskádovitý screening mezi příbuznými pacientů s FH. V celonárodní databázi evidujeme již více než 6 350 pacientů s FH, což představuje asi 16 % z očekávaného počtu pacientů v České republice. Takový záchyt nás řadí mezi nejúspěšnější země na světě, ale i s ohledem na příchod nových terapeutických možností zůstává detekce a včasné zahájení léčby nemocných s FH v centru naší pozornosti. Klíčová slova: familiární hypercholesterolemie – kardiovaskulární riziko – kaskádovitý screening – MedPed, Recent studies have revealed the prevalence of familial hypercholesterolemia (FH) is approximately twice higher than previously estimated and, thus, the disease affects one in 250 persons from the general population. Therefore FH remains the most frequent inherited metabolic disorder. Due to the genetic defect LDL-cholesterol accumulates both in the plasma and tissues leading to premature and accelerated atherosclerosis. Untreated patients with FH might suffer from myocardial infarction in the third or fourth decade, one third of these events being fatal. The disease is underdiagnosed and undertreated worldwide. In the Czech Republic the MedPed project focused on early diagnosis and initiation of proper treatment of FH aiming at lowering of the above mentioned risks was initiated in 1998. A crucial part of the project is so called cascade screening among the relatives of identified FH probands. There are 6,350 registered FH subjects in the nationwide registry, which represents 16% of the expected number of FH patients in the Czech Republic. This result of screening efforts ranks among the top countries in the world, however, also in spite of the recent expansion of FH treatment options early detection and initiation of treatment of FH remains in the centre of our attention. Key words: familial hypercholesterolemia – cardiovascular risk – cascade screening – MedPed, and Tomáš Freiberger, Michal Vrablík
Efekt rádiofrekvenčnej ablácie predsieňovokomorového spojenia môže byť sprevádzaný nežiadúcim vplyvom pravokomorovej stimulácie. Cieľom práce bolo zhodnotiť včasné hemodynamické dôsledky katétrovej ablácie u pacientov s trvalou fibriláciou predsiení rezistentnou na medikamentóznu liečbu. Metóda: Do štúdie sme zahrnuli 19 pacientov s priemerným vekom 66,9 ? 12,4 roka. V závislosti na bazálnej ejekčnej frakcii (EF) sme pacientov rozdelili do dvoch skupín (I. skupina pacientov s EF menej ako 50 %, II. skupina s EF 50 % a viac). Pacienti sa podrobili rádiofrekvečnej ablácii predsieňovokomorového spojenia a implantácii kardiostimulátora. Hemodynamické zmeny sme hodnotili pomocou stanovenia vývrhového (VO) a minútového objemu (MO) echokardiografickým spôsobom bazálne pred zákrokom a po zákroku pri rôznych frekvenciach stimulácie. Na presnejšie zhodnotenie stavu pacientov sme vytvorili indexy VOi a MOi ako pomer týchto veličín pri rôznych frekvenciach stimulácie voči ich bazálnej hodnote. Výsledky: U pacientov s nízkou EF stúpa VO pri všetkých frekvenciach stimulácie, pričom maximum účinku možno badať vo frekvenčnom pásme 60?100/min. Pri frekvencii stimulácie 60/min stúpol z 26,4 ml pred abláciou na 39,5 ml po ablácii. MO stúpa alebo sa nemení pri všetkých frekvenciach okrem frekvencie 60/min, pri ktorej zvýšenie VO nestačí kompenzovať pokles MO v dôsledku výrazného poklesu frekvencie. Pacienti v II. skupine mali pred abláciou vysokú hodnotu VO (52,3 ml). Po zákroku stúpol VO len pri frekvencii stimulácie 60 a 80/min (64,0 a 55,1 ml). Rovnako mali títo pacienti pred abláciou vysoký aj MO (6 097 ml). Po výkone MO poklesol pri všetkých frekvenciach stimulácie, ale vykazoval stúpajúcu tendenciu. Štatistickým vyhodnotením sme zistili negatívnu koreláciu medzi VOi a MOi na jednej strane a EF a priemerom ľavej komory v systole na druhej strane. Záver: Naše výsledky ukazujú, že rádiofrekvenčná katétrová ablácia atrioventrikulárneho uzla (RFCA AVN) je prínosom vo vybraných prípadoch pacientov v oboch skupinách, i keď mechanizmus zlepšenia klinického stavu je odlišný., Silvia Mišíková, Branislav Stančák, E. Komanová, and Lit. 33
Ernst Mach was already an internationally recognised experimental physicist, when he, after professorships for Mathematics and Physics in Graz and Experimental Physics in Prague, took over the chair for "Philosophy, particularly for the History and Theory of the Inductive Sciences", at the University of Vienna in 1895. This turn from natural sciences to philosophy was really an exception in the academic field. Although he was not a specialist in philosophy his ideas exhibited a remarkable influence. Here is the first part of the author's text, the second, closing part (Mach and Philosophy) will be published in the next issue of this Journal., Friedrich Stadler ; z angličtiny a němčiny přeložil M. Černohorský., and Obsahuje bibliografii