INTRAOCULAR BIODISTRIBUTION OF INTRAVITREAL INJECTED FLUORESCENT DEXAMETHASONE-CHITOSAN NANOPARTICLES IN RABBIT EYES.

AIM: To evaluate intraocular biodistribution of fluorescent nanoparticles composed of dexamethasone bound to chitosan after intravitreal administration in rabbit eyes. MATERIAL AND METHODS: The chitosan and gelatin based nanoparticles were synthetized using a reverse emulsion-double crosslinking technique (ionic and covalent) and then dexamethasone was bound. Two units of 1% suspension of these nanoparticles in saline solution were injected intravitreally into rabbit eyes. The histologic sections obtained at 72 hours were analyzed by confocal microscopy. RESULTS: The chitosan-fluorescein conjugate bound to dexamethasone was present in all ocular tissues at 72 hours. The nanoparticles were present in the retina and lens in a larger amount than in the other ocular tissues. CONCLUSIONS: The reverse emulsion-double crosslinking technique was efficient in synthesizing a biocompatible polymeric nanosystem. The in vivo study of intraocular biodistribution of fluorescein-marked nanoparticles capable of binding dexamethasone revealed their affinity for the retina and lens after intravitreal administration.

Thapsigargin-induced endoplasmic reticulum stress is not accompanied by mitochondrial membrane potential dissipation in murine pro-B cells.

UNLABELLED: There are almost no data concerning the involvement of endoplasmic reticulum stress (Ca2+ fluxes) in the apoptosis of the pro-B cell type Ba/F3. Thus, we aimed the characterization of thapsigargin-induced effects on Ba/F3 cells in vitro. MATERIAL AND METHOD: For some experiments Ba/F3 cells were treated with 1 microM thapsigargin for 24 hours. To compare, we used as positive control the effects of valinomycin 10 microM. The negative control Ba/F3 cells received no treatment for 24 hours. After that, all batches of Ba/F3 cells were incubated in the presence of 1 mimcroM JC-1 (Sigma-Aldrich) at 37 degrees C for 30 minutes. RESULTS: From the normal Ba/F3 JC-1-control cells (20.000 events gated by flow cytometry) 77.61 +/- 2.90% are associating high and 22.39 = 2.90% lower mitochondrial membrane potential. In the case of thapsigargin, 75.49 +/- 1.78% of the Ba/F3 cells are associating high and 24.51 +/- 1.78% lower mitochondrial membrane potential. CONCLUSIONS: While mitochondrial permeability transition pore (MPTP) opening necessarily correlates with a loss of mitochondrial membrane potential (Psi(mt)), a decrease in Psi(mt) does not necessarily indicate MPTP opening. Also, endoplasmic reticulum stress regulation of high cytosolic calcium levels by thapsigargin may prompt the opening of the MPTP without necessarily triggering irreversible pore activation or subsequent apoptogenic factors in Ba/F3 cells.

Apelin effects on lipopolysaccharide-increased pulmonary permeability in rats.

MATERIAL AND METHOD: Pretreatment with apelin-13 (AP-13, 2 mg/kg, i.p.), sodium butyrate (BUT, 200 mg/kg, s.c.) and N-acetyl-L-cysteine (NAC, 150 mg/kg, s.c.), all reduced the LPS-induced vascular leak measured as Evans blue extravasation, in rats lung tissue when compared to intranasal LPS (10 mg/100 mL) administered alone. RESULTS: Although there is a significant difference either between AP-13 and BUT on one hand, and NAC and BUT on the other hand pretreatments, there is no significant difference between AP-13 and NAC pretreatments. Firstly, apelin-13 pretreatment might justify its effects through the modulation of endothelial layer functions. We recently demonstrated that AP-13 could diminish the endothelial dysfunction of pulmonary vein from both ovalbumin sensitized rats and rats with pulmonary hypertension. Furthermore, pretreatment with AP-13 + BUT, AP-13+NAC as well as BUT+ NAC reduced the LPS-induced vascular leak when compared to LPS alone. The reduction effects of BUT and NAC association were higher than those of either BUT or NAC alone. These synergistic effects might be associated to different and additive mechanisms of action of BUT and NAC. Thus, BUT might be primarily effective on macrophage migration and secondarily on activation and cytokine secretion by macrophages and NAC might be primarily effective on macrophages activation. Furthermore, since there are no significant effects between AP-13, NAC and AP-13+NAC we can conclude that AP-13 and NAC effects might be mediated through the same mechanisms (with the possible involvement of nuclear transcription factor NF-kB).

[Platelet functions in acute and chronic experimentally induced hepatopathia]. / Cercetari asupra functiei plachetare in conditiile hepatopatiei experimentale acute si cronice.

UNLABELLED: It's well known the coagulation damage in chronic hepatitis and hepatic cirrhosis. The aim of our study was to quantify platelet dysfunction in acute and chronic toxic hepatitis. MATERIAL AND METHOD: We determined adhesivity, aggregability and icosanoids production in rats with acute and chronic hepatopathia induced by CCl4 administration. RESULTS: Our data shows that platelet adhesivity and aggregability are affected in chronic toxic affectation but also in acute intoxication (p < 0.05). Icosanoids production (expressed like MDA levels are significantly decreased only in chronic CCl4 intoxication (p < 0.001). Significantly correlation appears between aggregability and adhesivity in control group (r = 0.66) and between aggregability and MDA (r = -0.78) and adhesivity and MDA (r = -0.57) in lot C. CONCLUSION: Primary haemostasis and platelet dysfunction are involved in coagulation dysfunction in hepatic diseases and the modifications of platelet parameters also appeared in acute hepatic affectation.

New multifunctional textile biomaterials for the treatment of leg venous insufficiency.

Acryloyl monomers have been synthesized by reaction of beta-cyclodextrin and troxerutin with acryloyl chloride and grafted on a knitted material obtained from polyamide 6.6 and polyurethane fibers. Polyamide grafted with beta-cyclodextrin derivative binds troxerutin as a physical complex. The obtained biomaterials have been tested in vivo on rats for their ability to deliver troxerutin (a flebotonic drug) to different skin areas (epidermis, dermis and vascular wall). The results showed that the new synthesized materials can act as multifunctional bioactive textiles that can display both compression (given by the textile material) and sustained venotonic and haemostatic properties (given by the troxerutin delivered from biomaterial to the skin).

Adenosine involvement on bronchial reactivity modulation by diesel exhaust.

UNLABELLED: In recent decades, epidemiologic investigations have suggested a strong relationship between air pollution and an increase in the prevalence of allergic rhinitis and asthma. AIM: To investigate the possible involvement of adenosine (AD) in bronchomotor effects of diesel exhaust (DE). MATERIAL AND METHOD: Isolated bronchi from ovalbumin (OVA) sensitized rats were challenged in presence or absence of diesel exhaust extract (DEE). AD was delivered on organ bath before or after DEE, at concentrations did not produce significantly contractile effects. RESULTS: AD (0.1 microM) pre-treatment increased bronchomotor effects of DEE: amplified the bronchoconstrictor effects of OVA with more than 35% and decreased Emax of terbutaline induced bronchorelaxation of acetylcholine (Ach) preconstricted bronchial rings (up to 20%), but did not significantly modify ACh-induced contractions. OVA-induced contractions, ACh-induced contractions and terbutaline-induced relaxations have not been significantly modified as compare with DEE alone. On the other hand, DEE amplified AD (cumulative doses) contractile effects. CONCLUSION: These results confirmed our initial hypothesis that AD could partial mediate or at least, modulate DEE effects on airway reactivity.

Adipokines involvement in lung function.

The last two decades brings many data about white adipose tissue capacity to secrete hormones, named adipokines, which could mediate the relationship between obesity and lung diseases. In this paper we presented some data about adipokines involvement on pulmonary function, with special emphasis on leptin, adiponectin, tumor necrosis factor alpha, vascular endothelial growth factor, resistin, hepatocyte growth factor, interleukin-6, angiotensinogen and apelin.

[Interactions between angiotensin II and theophylline on isolated rat bronchi]. / Interactiunea angiotensina II--teofilina pe inele de bronhie de sobolan.

UNLABELLED: For more than half of century physicians are using theophylline for the treatment of obstructive pulmonary diseases. Because our previously results suggested the amplification of intrapulmonary renin angiotensin system (RAS) on ovalbumin (OVA) induced airway hyperresponsiveness we studied the interaction between theophylline and angiotensin II (Ang II) on normal versus sensitized rats. MATERIALS AND METHODS: we used main left bronchial rings mounted in wire myograph to assess the effects of Ang II and theophylline on airway smooth muscle. RESULTS: On both normal and OVA sensitized rats theophylline did not significantly modify either Ang II contractile effects or Ang II amplification of acetylcholine (ACh)-induced bronchoconstriction. On the other hand, on sensitized rat after antigen challenge, theophylline pretreatment reduced Ang II inhibition of terbutaline--induced relaxation of bronchial rings precontracted with ACh, increasing both EC50 and E(max) of terbutaline effects with 22.04 +/- 3.48% and 19.48 +/- 1.67%, respectively. CONCLUSION: These findings suggested that, in addition to bronchodilatory and antiinflammatory actions, theophylline could block some effects of intrapulmonary RAS activated in pathologically states as antigen sensitization and challenge.

Contractile effects of angiotensinogen and its multiple metabolization pathways on vessel walls.

The contractile effects of angiotensinogen (Aogen) and its metabolization pathways were studied on rat renal vein (RRV), rat pulmonary artery (RPA) and human umbilical vein (HUV) rings. Experiments were made in the presence or in the absence of pepstatin A (a renin inhibitor, 10 microM), captopril (an ACE inhibitor, 10 microM), chymostatin (a chymase inhibitor, 10 microM), amastatin (an aminopeptidase-A and -M inhibitor) or losartan (a specific AT1 blocker, 10 microM). On all rings, Aogen-induced contractions were reduced by pepstatin A or captopril, amplified by amastatin and blocked by losartan. Chymostatin had a stronger inhibitory effect than captopril on HUV and simultaneous administering of chymostatin and captopril prevented Aogen contractile effects on HUV. It is suggested that all studied vessels possess a local renin-angiotensin system and possibility of angiotensin II production within the vessel walls using various and species-dependent enzymatic pathways.

[Relationship diabetes mellitus-periodontal disease: etiology and risk factors]. / Binomul diabet zaharat-boala parodontala. Factori etiologici si de risc.

The interrelation between diabetes mellitus and inflammatory periodontal disease has been intensively studied for more than 50 years, a real bidirectional influence existing between patient's glycemic level disorder and periodontal territories alteration. Several studies developed in this direction emerged to the evidences that reveal a general increase of prevalence, extent and severity of gingivitis and periodontitis. Inflammation plays an important role in this interrelation, orchestrating both the periodontal disease and diabetes mellitus pathogeny and complications. Conversely, periodontal disease--infectious disease characterized by a significant inflammatory component--can seriously impair metabolic control of some diabetic patient. Moreover, treatment of periodontal disease and reduction of oral signs of inflammation may have a beneficial result on the diabetic condition (1). Less clear are the mechanisms governing this interrelation (even the literature is abundant in this direction), and, very probably, periodontal diseases serve as initiators of insulin resistance (in a way similar to obesity), thereby aggravating glycemic control. Further research is so imposed in order to clarify this aspect of the relationship between diabetes and periodontal disease.

Interactions between angiotensin I and acetylcholine on rat left main bronchial rings.

Angiotensin (Ang) II is known to amplified bronchoconstriction induced by acetylcholine (ACh). On the other hand all the components of renin angiotensin system were located on lungs. Contractile effects of Ang I (the precursor of Ang II) and interactions between Ang I and ACh on rat bronchial rings were characterize using angiotensin II type 1 (AT1) receptor antagonist (losartan), angiotensin converting enzyme (ACE) inhibitors (captopril and teprotide) and chymase inhibitor (chymostatin). We found that Ang I has contractile effects and amplified ACh-induced contractions. Blocking of AT1 receptors with 10 mM losartan significantly reduced 10 mM Ang I contractile effects (12.79 +/- 9.59% from 167.62 +/- 8.92%; p<0.05). Pre-treatment with 1 mM teprotide reduced 10 mM Ang I-induced contractions (35.68 +/- 7.83%; p>0.05). Captopril and teprotide only reduced Ang I actions. This suggested that both types of Ang I effects were mediated by AT1 receptors, but possibly conversion of Ang I into Ang II were not significantly dependent by ACE or chymase.

Chronic inflammatory rheumatismal diseases--paraclinical diagnosis.

The rheumatismal diseases constitute a major problem of public health, the pathology of the locomotor system representing today the main cause of invalidity in the world. The inflammatory chronic rheumatisms affect the young population, and, between the onset of the disease and diagnosis (approximately one year), the patient does not accuse major clinical complaints. In this context, the present work proposes a presentation of the main paraclinic methods and techniques, which may direct the clinician in giving a correct and early diagnosis of the main chronic inflammatory rheumatismal disorders. The paraclinic methods and techniques for assessing the intensity and evolution of the chronic rheumatismal inflammatory processes may be classified as follows: genetic, biological, histological, and imagistic. The inflammatory reaction is a nonspecific long-term reaction of the body defense systems, as response to the continuous and recurrent aggression. It is characterized by the predominance of the lymphocytes and macrophages at the level of the focus infectious and an intense process of neoangiogenesis and fibroblastic proliferation accompanies it. The paraclinic methods and techniques for assessing the intensity and evolution of the chronic rheumatismal inflammatory processes may be classified as follows: genetic, biological, histological, and imagistic.

Are polyamines involved in the contractile effects of angiotensin II in the rat aorta? (Polyamines and angiotensin II in rat aorta).

Angiotensin II (AII) is a central factor involved in the pathophysiology of arterial hypertension and atherosclerosis. On the other hand, polyamines represent a family of organic cations with low molecular weight, playing intracellular regulatory roles essential for the cellular growth and differentiation. The cellular contents, the synthesis and the transport of polyamines are increased following the actions of AII, as well as of other cellular growth factors. Our results show that the administration of polyamines as pre-treatment modulates the contractile effects of extracellular AII (80 nM). This modulation is concentration-dependent and dual: the lower concentrations amplify and the higher concentrations reduce the effects of AII in the isolated rat aorta rings without endothelium. Moreover, DL-alpha-Difluoromethylomithine (DFMO), a specific inhibitor of ornithine decarboxylase, does not significantly modify the contractile effects of AII. Thus, these data suggest that polyamines generated through this metabolic pathway are not involved in the contractile effects of AII in rat aortic vascular smooth muscle.

Interactions between extracellular and intracellular administered angiotensin II in isolated rat portal vein rings.

It is already demonstrated that intracellular angiotensin II (Ang II) stimulates smooth muscle contraction and cell growth. We studied the contractile effects of Ang II intracellular delivered by the means of liposomes (LAngII) and also the interactions between intracellular and extracellular administered Ang II on the rat portal vein rings without endothelium. The results were expressed as the percentages of the control contraction (K+ 40 mM; mean +/- S.E.M). LAngII induced contractions were of 120.46 +/- 8.06%. On the other hand, 0.1 microM Ang II produced contractions of 121.43 +/- 6.83%. Both Ang II and losartan, administered either extracellular in the organ bath or intracellular by the means of liposomes, inhibited the contractions induced by intracellular Ang II. The inhibitory effects of losartan on LAngII-induced contractions were dose-dependent. Thus, 10 microM losartan strongly blocked (10.01 +/- 1.41%) and 1 microM losartan partially blocked (39.73 +/- 5.35%) the LAngII-induced effects. LLOS significantly inhibited the LAngII contractile effects (38.51 +/- 8.92%). Our results revealed that LAngII partially inhibited the contractions induced by extracellular administered Ang II (42.42 +/- 3.29%). On the other hand, 0.1 microM Ang II also inhibited the contractile effects induced by LAngII (67.42 +/- 0.76%), although a little bit less. So, contractions induced by Ang II administered intracellular are mainly mediated by intracellular Ang II receptors sensitive to losartan. At the same time, the participation of cell membrane angiotensin receptors to intracellular Ang II effects cannot be excluded.

[Polyamines antagonizing angiotensin II contractile effects in isolated rat aorta]. / Antagonizarea efectelor contractile ale angiotensinei II de catre poliamine la nivelul aortei izolate de sobolan.

Our study showed that the administration in pre-treatment of some polyamines (especially spermine and spermidine and almost null agmatine, putrescine and cadaverine) reduced the contractile effects of angiotensin II (Ang II) in isolated rat aorta. These effects might not be associated to the interference of clathrin coated vesicles (coated pits) formation or caveolae interaction (and thus to Ang II internalization through AT1 receptors). In contrast, these effects seem to be due to the interaction with voltage-gated membrane Ca2+ channels. Therefore, the alteration of transmembrane Ca2+ fluxes does not exclude the involvement of internalization process through coated pits or caveolae, since the endocytosis mediated by these phenomena essentially needs Ca2+. In addition, the inhibitory effects are dependent on the number of positive charges of the polyamine molecules.

[Interactions between angiotensin-(1-7)and angiotensin II in isolated rat portal vein]. / Interactiuni ale Angiotensinei-(1-7) cu Angiotensina II la nivelul venei porte izolate de sobolan.

Our preliminary data show for the first time the interaction between angiotensin-(1-7) (Ang-(1-7)) and angiotensin II (Ang II, 10 nM) in isolated rat portal vein. Very low concentrations (10 nM) of Ang-(1-7) have marked functional antagonizing effects on Ang II-induced contractions. High concentrations of Ang-(1-7) (1-10 mM) do not affect the effects of Ang II. The effects of low concentration Ang-(1-7) might be associated to the interaction with Ang-(1-7) specific receptors and the own contractile effects (approximatively 28%) at high concentrations might be assign to the interaction with angiotensin specific receptors AT1. But, the lack of effects of Ang-(1-7) high concentrations on Ang II-induced contractions hardly might be associated to the interaction with AT1 receptors. Although losartan was entirely blocking the Ang-(1-7) effects, there is in the literature a series of data showing that Ang-(1-7) specific receptors (or a subtype of Ang-(1-7) receptors) might be sensible (with possible high affinity) to losartan. Additional experiments are thus necessary to further clarify these interactions.

[Alternative pathways for the activation of the renin-angiotensin system]. / Cai alternative de activare ale sistemului renina-angiotensina.

The knowledge of the structure and function of the components of the renin-angiotensin system (RAS) is rapidly increasing. The classic pathway of angiotensin (Ang) II generation includes a reaction catalyzed by angiotensin-converting enzyme (ACE). We actually discuss the alternative pathways for the generation of Ang-II and other angiotensin peptides (Ang III, Ang IV, Ang (1-9), Ang (1-7), des-Asp-Ang I) and the responsible enzymes (tonins, cathepsins, chymases, aminopeptidases, dipeptidyl aminopeptidases, neutral endopeptidases, carboxypeptidases, ACE2 etc.). The development of novel enzyme inhibitors (e.g., nafamostat, sampatrilat) for more efficacious suppression of RAS activity is also considered.

[Effects of polyamine-loaded liposomes on liver mitochondrial permeability transition]. / Efectele poliaminelor încarcate în lipozomi asupra permeabilitatii tranzitorii mitocondriale (PTM) hepatice.

The objective of the present study was represented by the effects of polyamineloaded liposomes on hepatic mitochondrial permeability transition (MPT). MPT was appreciated through the swelling of the isolated guinea-pig liver mithocondria induced by Ca2+, at 540 nm, using a diode-array 8452 UV-VIS spectrophotometer and a General Purpose software (Hewlett-Packard). Polyamines encapsulated in liposomes might inhibit the appearance of MPT induced by Ca2+, directly proportional to electrical charge: spermine > spermidine > putrescine > cadaverine. Thus, together with some previous data, it was observed that spermine may modulate hepatic MPT from the exterior, as well as from the interior of mitochondria. Moreover, spermidine and putrescine may also modulate MPT from the interior of mitochondria at low doses, and from the exterior only at high doses. The changes in mitochondrial membranes lipid composition (as done by control liposomes) are slightly influencing the MPT. The increase in membrane rigidity through the use of 40% cholesterol-enriched liposomes is drastically decreasing the appearance and development of MPT.

[Xanthine derivative compounds potential activity in inflammatory process]. / Compusi cu structura xantinica potential activi în procesul inflamator.

We studied the potentially anti-inflammatory action of some new xanthine compounds, theophylline derivatives with 7-[2-hydroxy-3-(4-acetamido)-phenoxy-propyl]-8-R-1,3-dimethyl-xanthine and 8-R-1,3-bis-(1,3-dimethyl-xanthin-7yl)-2-hydroxy-propane structure substituted in 7 and 8 position. Almost all studied compounds reduced the inflammatory edema, the effect being comparable or highest theophylline. The antiinflammatory effect of theophylline intensified with the introduction in 7 position the theophylinyl radical and in 8 position the bromo, nitro, pirolidinyl, piperidinyl, morfolinyl, imidazolyl, 3,5-dimethyl-pirazolyl, 3-methyl-5-oxo-pirazolyl radicals.

Pepstatin A is inducing contractile effects on isolated rat aorta rings.

In a series of experiments dealing with the effects of angiotensin I (AI) and angiotensinogen on isolated rat aorta we observed that pepstatin A was able to induce contractile effects by itself. The endothelin pathway was excluded by the inhibitory effects of captopril, chymostatin and amastatin. In addition, few preliminary experiments showed that the contractile effects of pepstatin A were inhibited by the pretreatment with losartan, an antagonist of AT1 angiotensin receptors. Pepstatin A-induced contractile effects on isolated rat aorta were inhibited with high potency by captopril, chymostatin and amastatin and were totally blocked by captopril + amastatin and captopril + chymostatin. Finally, we concluded that the pepstatin A-induced contractile effects on isolated rat aorta rings are dependent on an angiotensinogen vascular pool, compulsory involve an angiotensin-converting enzyme-1 (ACE-1) mediated pathway and one or more non-classical pathways for the generation of angiotensin peptides. Further experiments are necessary to elucidate the mechanisms associated to pepstatin A-induced effects.