The effects of nimodipine and L-NAME on coronary flow and oxidative stress parameters in isolated rat heart

The aim of this study was to assess the effects of Ca2+ channel antagonist nimodipine (in concentration which competitive inhibited phosphodiesterase 1--PDE1) on oxidative stress alone or under inhibition of nitric oxide synthase by L-NAME in isolated rat heart. The hearts from male Wistar albino rats (n=18, BM about 200 g, age 8 weeks) were retrograde perfused according to the Langendorff technique at gradually increased constant perfusion pressure conditions (CPP, 40-120 cm H2O). The experiments were performed under control conditions, in the presence of Nimodipine (2 microM) or Nimodipine (2 microM) plus L-NAME (30 microM). Coronary flow (CF) varied in the autoregulatory range from 3.7 +/- 0.4 ml/min/g wt at 50 cm H2O to 4.35 +/- 0.79 at 90 cm H2O. Basal nitrite outflow, index of lipid peroxidation (measured as TBARS release) and superoxide anion release (O2-) (at 60 cm H2O) were 0.64 +/- 0.18 nmol/min/g wt, 0.55 +/- 0.13 micromol/min/g wt and 19.72 +/- 3.70 nmol/min/g wt, respectively. Nimodipine induced significant vasodilation at all values of CPP (from 26% at 40 cm H2O to 36% at 120 cm H2O) accompanied with significant decrease of nitrite outflow (from 59% at 40 cm H2O to 40% at 120 cm H2O), significant increase of TBARS above autoregulatory range (about 40%) and significant increase of O2- release (from 186% at 40 cm H2O to 117% at 120 cm H2O). However, perfusion with L-NAME completely reversed the effects of Nimodipine. Nimodipine-induced flow changes were decreased under L-NAME (from 3% at 40 cm H2O to 11% at 120 cm H2O) without changes in the autoregulatory range, accompanied with significantly increased nitrite outflow (from 69% at 40 cm H2O to 36% at 120 cm H2O) and TBARS release (almost 50%), as well as significantly decreased O2- release (from 50% at 40 cm H2O to 43% at 120 cm H20). Our findings show that effect of nimodipine on coronary flow should be significantly influenced by NO, TBARS and O2- release in isolated rat heart.     

Composition and functional characterization of yeast 66S ribosome assembly intermediates

The pathway and complete collection of factors that orchestrate ribosome assembly are not clear. To address these problems, we affinity purified yeast preribosomal particles containing the nucleolar protein Nop7p and developed means to separate their components. Nop7p is associated primarily with 66S preribosomes containing either 27SB or 25.5S plus 7S pre-rRNAs. Copurifying proteins identified by mass spectrometry include ribosomal proteins, nonribosomal proteins previously implicated in 60S ribosome biogenesis, and proteins not known to be involved in ribosome production. Analysis of strains mutant for eight of these proteins not previously implicated in ribosome biogenesis showed that they do participate in this pathway. These results demonstrate that proteomic approaches in concert with genetic tools provide powerful means to purify and characterize ribosome assembly intermediates.     

Occlusal molar surfaces in females with Turner's syndrome

The aim of this study was to identify the molar occlusal features in 73 subjects with the Turner's syndrome (TS) and compared to a control group (CG) of 322 healthy females. The occlusal features were scored on dental plaster casts using the Scoring Procedures for Key Morphological Traits of the Permanent Dentition: The Arizona State University Dental Anthropology System (ASU). The results were analyzed through frequency, percentage and chi 2-test. TS subjects have more frequent reduction of cusp number, distolingual cusp on the upper molars and distal cusp on the lower molar, with the consequent reduction of the occlusal surface. Reduced size of occlusal surface and number cusps on upper molars resulted in the transformation of rhomboid occlusal shape into triangular, with the consequent loss of H-shaped groove system (in the upper right first molars H-shaped groove system was significantly less frequently found in TS (p < 0.05); in the upper left second molars H-shaped groove system was significantly less frequently found in TS (p < 0.01). The X-chromosome aneuploidy can cause a decrease in developmental homeostasis, which results in the alteration of apposition of the enamel and in consequently substantial changes of the molar occlusal morphological features.     

The activity of antioxidant defence enzymes in the mussel Mytilus galloprovincialis from the Adriatic Sea

The activity of the antioxidant defence enzymes superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), glutathione peroxidase (GSH-Px, EC 1.11.1.9), glutathione reductase (GR, EC 1.6.4.2) and the phase II biotransformation enzyme glutathione-S-transferase (GST, EC 2.5.1.18) in whole mussels (Mytilus galloprovincialis) were studied. The mussels were collected in winter and in spring at two localities in the Adriatic Sea: Bar Port and Tivat Bay. Our results show that the activities of SOD, GSH-Px and GST were seasonally dependent with higher activities in winter. GR activity was also higher in winter, but only in mussels from Bar Port. In mussels from Tivat Bay, GR activity was lower in winter compared to spring. In addition, a decrease in CAT activity in mussels from Bar Port compared to those from Tivat Bay was found. It can be concluded that seasonal variations should be incorporated into interpretation of biomonitoring studies in mussels.     

Biotransformation of nitric oxide in the cerebrospinal fluid of amyotrophic lateral sclerosis patients

Recent findings indicate that nitric oxide (NO*) over-production might be an important factor in the pathogenesis of sporadic amyotrophic lateral sclerosis (SALS). We measured significantly higher concentrations of uric acid and thiol group-containing molecules (R-SH groups) in the cerebrospinal fluid (CSF) from SALS patients compared to controls. The above factors, together with a slightly increased free iron concentration found in the CSF, favour conditions necessary for the formation of the dinitrosyl iron complex, capable of NO* bio-transformation. Thus, we performed ex vivo saturation of CSF (from both SALS patients and controls) with NO*. A decrease in the level of R-SH was found. This was more pronounced in the CSF from SALS patients. In the CSF from SALS patients the production of nitrite and hydroxylamine was greater than that observed in the CSF from controls. Moreover, we also found increased Cu,Zn-SOD activity in the CSF from SALS patients (when compared to control subjects) but no activity corresponding to Mn-SOD in any CSF samples. As Cu,Zn-SOD can react with nitroxyl forming NO*, the conditions for a closed, but continuous, loop of NO* biotransformation are present in the CSF of ALS patients.     

Endogenous Regulation of Endothelial Cell Proliferation

Bovine aortic endothelial cells (BAEC) in culture have the ability to regulate their own proliferation. We have found that a fraction below 100,000 daltons obtained from the media of confluent cultures of BAEC inhibits tritiated thymidine [³H]TdR incorporation as well as their proliferation. the inhibition is dose- and time-dependent; maximum inhibition of [³H]TdR incorporation occurs 8 hr after cells are released from synchronization and the inhibitory fraction is added. Inhibition is evident at concentrations as low as 50 μg/ml and reaches a maximum at 600 μg/ml. the blockage of [³H]TdR incorporation is reflected in the inhibition of cell proliferation. In the presence of 400 μg of endogenous inhibitor per ml of media, added at the time of plating, the average population doubling time increases from 19 to 41 hr. These findings indicate that, in culture, BAEC can regulate their own proliferation by synthesizing an endogenous inhibitor(s) of proliferation.     

The effects of zofenopril on cardiac function and pro-oxidative parameters in the streptozotocin-induced diabetic rat heart

Diabetes mellitus is a chronic condition that continues to increase in both incidence and prevalence. Renin–Angiotensin–Aldosterone System is one of the main modulators of chronic hyperglycaemia and, thus, its influence on tissues. Hyperglycaemia-induced oxidative stress is an important factor in diabetic cardiomyopathy. The present study was carried out on 24 adult male Wistar albino rats (8-week-old and with body masses of 190 ± 10 g). We evaluated the influence of acute administration of zofenopril on ex vivo myocardial function from rats with streptozotocin-induced diabetes mellitus, with a special emphasis on cardiodynamic and oxidative stress parameters in diabetic rat hearts. Rats were divided randomly into two groups (12 animals per group): control non-diabetic animals (C) were healthy rats perfused with 1.5 µM of zofenopril, and STZ-treated diabetic animals (DM) were diabetic animals perfused with 1.5 µM of zofenopril 4 weeks after the induction of diabetes. Our results demonstrated that diabetic rats are characterized by a depressed cardiac performance and that oxidative markers are related to alterations in cardiac function in rats with 4 weeks of STZ-induced diabetes. Additionally, the use of zofenopril as a monotherapy slightly diminished cardiac damage induced by chronic hyperglycaemia. However, long-term follow-up intervention trials are necessary to fully demonstrate the benefit of zofenopril in this context. A challenge for future investigations will be to identify the effects of chronic administration or combination therapy with angiotensin-converting enzyme inhibitors in various models of diabetes.     

The effects of verapamil and its combinations with glutamate and glycine on cardiodynamics,coronary flow and oxidative stress in isolated rat heart

The role of N-methyl-D-aspartate receptor (NMDA-R) in heart is still unclear. For these ionotropic glutamate receptors is characteristic the necessity of both co-agonists, glutamate and glycine, for their activation, which primarily allows influx of calcium. The aim of the present study was to examine the effects of verapamil, as a calcium channel blocker, alone and its combination with glycine and/or glutamate on cardiac function, coronary flow, and oxidative stress in isolated rat heart or to examine the effects of potential activation of NMDA-R in isolated rat heart. The hearts of male Wistar albino rats were excised and perfused according to Langendorff technique, and cardiodynamic parameters and coronary flow were determined during the administration of verapamil and its combinations with glutamate and/or glycine. The oxidative stress biomarkers, including thiobarbituric acid-reactive substances, nitrites, superoxide anion radical, and hydrogen peroxide, were each determined spectrophotometrically from coronary venous effluent. The greatest decline in parameters of cardiac contractility and systolic pressure was in the group that was treated with verapamil only, while minimal changes were observed in group treated with all three tested substances. Also, the largest changes in coronary flow were in the group treated only with verapamil, and at least in the group that received all three tested substances, as well as the largest increase in oxidative stress parameters. Based on the obtained results, it can be concluded that NMDA-R activation allows sufficient influx of calcium to increase myocardial contractility and systolic pressure, as well as short-term increase of oxidative stress.     

Deoxyribonuclease I Inhibitory Properties,Molecular Docking and Molecular Dynamics Simulations of 1-(Pyrrolidin-2-yl)propan-2-one Derivatives

Deoxyribonuclease I (DNase I) inhibitory properties of two 1-(pyrrolidin-2-yl)propan-2-one derivatives were examined in vitro. Determined IC₅₀ values of 1-[1-(4-methoxyphenyl)pyrrolidin-2-yl]propan-2-one ( 1 ) (192.13±16.95 μM) and 1-[1-(3,4,5-trimethoxyphenyl)pyrrolidin-2-yl]propan-2-one ( 2 ) (132.62±9.92 μM) exceed IC₅₀ value of crystal violet, used as a positive control, 1.89- and 2.73-times, respectively. Compounds are predicted to be nontoxic and to have favorable pharmacokinetic profiles, with high gastrointestinal absorption and blood-brain barrier permeability. Molecular docking and molecular dynamics simulations suggest that interactions with Glu 39, Glu 78, Arg 111, Pro 137, Asp 251 and His 252 are an important factor for inhibitors affinity toward the DNase I. Determined inhibitory properties along with predicted ADMET profiles and observed interactions would be beneficial for the discovery of new active 1-(pyrrolidin-2-yl)propan-2-one-based inhibitors of DNase I.     

Thermal robustness of signaling in bacterial chemotaxis

Temperature is a global factor that affects the performance of all intracellular networks. Robustness against temperature variations is thus expected to be an essential network property, particularly in organisms without inherent temperature control. Here, we combine experimental analyses with computational modeling to investigate thermal robustness of signaling in chemotaxis of Escherichia coli, a relatively simple and well-established model for systems biology. We show that steady-state and kinetic pathway parameters that are essential for chemotactic performance are indeed temperature-compensated in the entire physiological range. Thermal robustness of steady-state pathway output is ensured at several levels by mutual compensation of temperature effects on activities of individual pathway components. Moreover, the effect of temperature on adaptation kinetics is counterbalanced by preprogrammed temperature dependence of enzyme synthesis and stability to achieve nearly optimal performance at the growth temperature. Similar compensatory mechanisms are expected to ensure thermal robustness in other systems.