Cilj: Prirođena disfunkcija pulmonalne valvule i/ili disfunkcija atipičnog Botallova duktusa u fetalnom životu mogu biti izvorom širokog spektra kardiovaskularnih anomalija. Ciljevi ovog rada jesu ...opis kliničke slike,
prikaz slikovnih dijagnostičkih metoda prenatalno (fetalna ehokardiografija) i postpartalno (ehokardiografija, angiokardiografija, MSCT) te metode liječenja i tijek bolesti ove rijetke anomalije. Sekundarni je cilj upoznati čitateljstvo s ovim stanjem koje se često previdi. Metode i rezultati: Prikazujemo četvero bolesnika s entitetom što se očituje afunkcionalnom pulmonalnom valvulom s različitim stupnjem stenoze i insuficijencije te patološkom dilatacijom glavnog stabla i desne grane plućne arterije, a koji su i uzrokom patološke impresije na velike dišne putove i konzekutivne respiratorne insuficijencije, možda i s letalnim ishodom. Barem u troje bolesnika postoji i patološki Botallov duktus, a u većine postoji spektar patoloških promjena u desnim srčanim šupljinama: hipertrofija desne klijetke, razvoj slike nekompaktne kardiomiopatije, trikuspidalna insuficijencija, ali i moguća disfunkcija lijeve klijetke. Dvojica se bolesnika uspješno liječe jer smo se držali propisanih smjernica iz novije literature: 1. prenatalna dijagnoza kao imperativ, 2. rana kardiokirurška operacija s implantacijom valvuliranog provodnika u izlazni trakt desne klijetke, 3. plikacija pulmonalne arterije ili „LeCompteov manevar“ radi oslobađanja bronha od kompresije. Dvije bolesnice umrle su zbog insuficijencije desne klijetke ili respiratorne insuficijencije uzrokovane kompresijom na dišne putove. Ni u jednog bolesnika nismo utvrdili delecijski sindrom (delecije 22q11.2 ili 18q) koji se spominje u etiopatogenetskom razmatranju ove anomalije kao dio spektra konotrunkalnih anomalija. Zaključak: Prirođena manjkavost pulmonalne valvule i/ili disfunkcija atipičnog Botallova duktusa u fetalnom životu mogući su razlog displazije pulmonalne valvule koja postaje afunkcionalna s posljedičnom stenozom i insuficijencijom te spektrom anomalija u desnim kardiovaskularnim strukturama. Preduvjeti za uspješno liječenje jesu rano prepoznavanje sindroma (prenatalna dijagnostika), rana kardiokirurška intervencija (ligatura duktusa i ugradnja valvuliranog provodnika između desne klijetke i plućne arterije) te plikacija aneurizmatski proširenih plućnih arterija i oslobađanje dišnih putova od njihova pritiska. Spektar promjena bolje se raspoznaje ako se razmatra teoretska pretpostavka o mogućem poremećaju migracije neuroektoderma u mezenhimalnu osnovu za srce kao i kod drugih konotrunkalnih anomalija.
The body surface of homeothermic organisms produces constant microvibrations. In the past, many studies were conducted on this topic, and the amplitude of the microvibrations was described as a ...sensitive marker of muscle tension and body activity. Subsequent studies indicated that the frequency of the microvibrations is an important variable affecting the body. The aim of this research was to examine the effects of the vibroacoustic microvibrations on the rate, rhythm and structure of the rat heart during physiological conditions. Microvibrations of specific frequency and amplitude were induced by a Vitafon-T, four different modes were used, and the effects of the microvibrations on ECG characteristics and the wall structure of the rat heart were examined. After the application of microvibrations (lasting 10-60 min), no statistically significant changes occurred in the heart rate, but the amplitudes significantly increased after 10, 20 and 30 minutes, and increased even more after 60 minutes. No changes in the heart wall structure were found. Acute in vivo application of vibroacoustic microvibrations in the rats did not produce significant effects on the heart rate and rhythm; however, it increased the amplitude of the R wave by 25-32% in the second standard ECG lead but did not lead to structural changes in the rat heart wall.
Površina tela homeoterma konstantno proizvodi vibracije. U prošlosti su sprovedena mnoga istraživanja na temu mikrovibracija, i opisala amplitudu mikrovibracija kao osetljiv parametar mišićne tenzije i telesne aktivnosti. Kasnija istraživanja su frekvenciju mikrovibracija navela kao varijablu od centralnog značaja za njihove efekte na organizam. Cilj istraživanja je bio da ispitamo efekte vibroakustičkih mikrovibracija na frekvenciju, ritam i strukturu srca pacova u fiziološkim uslovima. U istraživanju je korišćen aparat koji proizvodi mikrovibracije, Vitafon-T određene frekvencije i amplitude, i u skladu sa tim koristili smo četiri režima rada u kojima smo ispitivali efekte mikrovibracija na EKG karakteristike i strukturu zida srca pacova. Utvrdili smo da nakon primene mikrovibracija (u trajanju od 10-60 minuta) nije došlo do statistički značajnih promena u broju otkucaja, vrednosti amplitude R talasa su statistički značajno povećane posle 10, 20 i 30 minuta, a visoko statistički značajno povećane posle 60 minuta. Na preparatu zida srca nema promena u odnosu na normalnu strukturu. Akutna primena vibroakustičkih mikrovibracija kod pacova in vivo ne utiče značajno na frekvenciju i ritam srčanog rada, povećava amplitudu R talasa u drugom standardnom EKG odvodu za 25-32 % i ne dovodi do promena u strukturi zida srca pacova.
Increased activity of the renin-angiotensin-aldosterone system (RAAS) plays a significant role in the development and progression of various cardio-metabolic diseases, such as hypertension, ...atherosclerosis and heart failure. Aliskiren is the newest antihypertensive drug and the first orally active direct renin inhibitor to become available for clinical use. This study investigated the acute and direct effects of Aliskiren on different parameters of oxidative stress on isolated rat heart. The hearts of male Wistar albino rats (n = 24, 8 per experimental group, age 8 weeks, body mass 180–200 g), were excised and retrogradely perfused according to the Langendorfftechnique at a gradually increasing perfusion pressure (40-120 cmH
O). Markers of oxidative stress (NO
, TBARS, H
and O
) were measured spectrophotometrically after perfusion with three different concentrations of Aliskiren (0.1 μM, 1 μM, and 10 μM). The results demonstrated possible dose-dependent cardioprotective properties of Aliskiren, particularly with higher CPP. Lipid peroxidation (TBARS) levels decreased with the highest dose of Aliskiren and higher CPP, and the same trend was observed in nitrite (NO
) and hydrogen peroxide (H
) levels. These findings indicate that the acute effects of Aliskiren do not likely promote the production of reactive oxygen species upon higher pressure with the highest dose. Aliskiren may exert beneficial effects on oxidative stress biomarkers.
Asymmetrical thin membranes of SrCe
0.95Y
0.05O
3−
δ
(SCY) were prepared by a conventional and cost-effective dry pressing method. The substrate consisted of SCY, NiO and soluble starch (SS), and the ...top layer was the SCY. NiO was used as a pore former and soluble starch was used to control the shrinkage of the substrate to match that of the top layer. Crack-free asymmetrical thin membranes with thicknesses of about 50
μm and grain sizes of 5–10
μm were successfully pressed on to the substrates. Hydrogen permeation fluxes (
J
H
2
) of these thin membranes were measured under different operating conditions. At 950
°C,
J
H
2
of the 50
μm SCY asymmetrical membrane towards a mixture of 80% H
2/He was as high as 7.6
×
10
−8
mol/cm
2
s, which was about 7 times higher than that of the symmetrical membranes with a thickness of about 620
μm. The hydrogen permeation properties of SCY asymmetrical membranes were investigated and activation energies for hydrogen permeation fluxes were calculated. The slope of the relationship between the hydrogen permeation fluxes and the thickness of the membranes was −0.72, indicating that permeation in SCY asymmetric membranes was controlled by both bulk diffusion and surface reaction in the range investigated.
The hydrogen permeability of SrCe
0.95Eu
0.05O
3−
δ
and SrCe
0.95Sm
0.05O
3−
δ
was studied as a function of temperature, hydrogen partial pressure (
P
H
2
) gradient, and water vapor partial pressure ...(
P
H
2O
) gradient. Under a 100% dry hydrogen condition at 1123 K, the hydrogen permeation rates of dense membranes (1.72 mm thick) are ≈3.19×10
−9 mol/cm
2 s for SrCe
0.95Eu
0.05O
3−
δ
and 2.33×10
−9 mol/cm
2 s for SrCe
0.95Sm
0.05O
3−
δ
. Under wet hydrogen conditions at 1123 K, the hydrogen permeation rates are ≈2.89×10
−9 and 1.21×10
−9 mol/cm
2 s, respectively, for the same materials. The dopant dependence of hydrogen permeability is explained in terms of the ionization potential of the dopant. Electronic conductivity was calculated from hydrogen permeation fluxes; activation energies for electron conduction under both dry and wet conditions were also calculated. The
P
H
2O
dependence of electronic conductivity and hydrogen permeability is discussed.
Eicosanoids lead to the promotion of inflammation, cause fever and pain and have many other eff ects. NSAIDs block the action of cyclooxygenase (COX) during the process of converting arachidonic acid ...into inflammatory mediators, thus reducing the symptoms of inflammation. Investigations focusing on nonselective COX inhibitors, used in high doses, revealed harmful eff ects on myocardial function. Th e aim of our study was to assess the eff ects of two nonselective NSAIDs, diclofenac and ibuprofen, on cardiodynamic parameters, coronary flow and oxidative stress biomarkers in isolated rat hearts. Th e hearts of male Wistar albino rats were excised and retrogradely perfused according to the Langendorff technique at gradually increased coronary perfusion pressures (40-120 cm H
O). Th e experiments were performed under controlled conditions (Krebs-Henseleit physiological solution). Th e hearts were perfused with 10 μmol/l diclofenac and 10 μmol/l ibuprofen. Th e heart function parameters, including the maximum rate of pressure development (dp/dt max), minimum rate of pressure development (dp/dt min), systolic left ventricular pressure (SLVP), diastolic left ventricular pressure (DLVP), mean perfusion pressure (MBP) and heart rate (HR), were continuously registered. Coronary flow (CF) was measured flowmetrically. Oxidative stress markers, including the index of lipid peroxidation measured as TBARS, nitric oxide measured through nitrites (NO
-), superoxide anion radical (O
-), and hydrogen peroxide (H
) in the coronary venous effluent, were assessed spectrophotometrically. Our results showed that diclofenac aff ected cardiodynamic parameters more significantly than did ibuprofen. Furthermore, the present data indicate that both estimated COX inhibitors do not promote the production of reactive oxygen species.
Eikosanoidi dovode do zapaljenja, uzrokuju groznicu i bol, i imaju mnoge druge efekte na organizam. NSAID onemogućavaju delovanje ciklooksigenaze (COX) u procesu konvertovanja arahidonske kiseline u medijatore zapaljenja, i na taj način smanjuju simptome zapaljenja. Istraživanja koja se bave primenom neselektivnih inhibitora COX, koji se koriste u visokim dozama, pokazala su njihove štetne efekte na funkciju miokarda. Cilj našeg istraživanja je bio da ispita efekte neselektivnih NSAID, diklofenaka i ibuprofena, na kardiodinamske parametre, koronarni protok i biomarkere oksidativnog stresa izolovanog srca pacova. Srca mužijaka Wistar albino pacova su uzimana i retrogradno perfundovana prema Langedorff -ovoj tehnici sa postepenim povećanjem perfuzionog pritiska (40-120 cm H
O). Eksperimenti su prvo izvođeni u kontrolnim uslovima (primena fiziološkog Krebs-Henseleit-ovog rastvora), nakon čega su srca perfundovana sa: 10 μmol/l dikolfenaka i 10 μmol/l ibuprofena. Parametri srčane funkcije koji su kontinuirano praćeni su: maksimalna stopa razvoja pritiska (dp/dt max), minimalna stopa razvoja pritiska (dp/dt min), sistolni pritisak u levoj komori (SLVP), dijastolni pritisak u levoj komori (DLVP), srednji perfuzioni pritisak (MBP) i frekvenca srčanog rada (HR). Koronarni protok (CF) je registrovan floumetrijski. Markeri oksidativnog stresa: indeks lipidne peroksidacije meren kao TBARS, azot-monoksid utvrđivan preko nitrata (NO
-), superoksid anjon radikal (O
-), i vodonik peroksid (H
) su mereni spektrofotometrijski u koronarnom venskom efluentu. Naši rezultati su pokazali da diklofenak ispoljava značajniji uticaj na kardiodinamske parametre u odnosu na ibuprofen. Pored toga, rezultati ove studije su pokazali da oba ispitivana inhibitora COX ne dovode po produkcije reaktivnih vrsta kiseonika.
The University Computing Centre (SRCE) established its presence on Internet based social networks in November 2009, namely on Facebook. Soon after, SRCE become present on Twitter, Google+, YouTube, ...LinkedIn and foursquare. Maintaining the presence and communication on social networks was initially one of the activities carried out by the SRCE Helpdesk service. However, as a result of the growing workload and responsibilities of the Helpdesk, a new service was established only for activities related to social networks. This paper discuses the communication strategy used by SRCE on social networks. The authors examined different web based tools and services to gather information about Internet users who follow SRCE's activities on different social network. A data analysis shows that the initial goals SRCE set in 2009 related to its communication strategy on social networks have been fulfilled. This data will also be used as a starting point for reconsideration of the existing communication strategy. With the emergence of new popular social networks there might be a need for expansion.
Mixed proton–hole conducting ceramic, SrCe
0.95Yb
0.05O
3−
α
(SCYb), hollow fibre membranes have been prepared using a combined immersion-induced phase inversion and sintering technique. Two ...different sintering routes have been adopted in studying the effect of sintering temperatures on gas-tight properties and mechanical strength of the prepared membranes. By employing longer time of heat treatment after thermolysis (i.e. removal of organic binders and additives at 600
°C), the final sintering temperature for preparation of the gas-tight SCYb hollow fibre membranes can be reduced. In addition, mechanical strength of the sintered membrane is found to be remarkably improved. The performance of the prepared SCYb hollow fibre membrane in terms of hydrogen permeation (proton conduction) has also been investigated experimentally.
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