Search

Resveratrol (trans-3,4',5-trihydroxystilbene, CAS 501-36-0), a natural antioxidant and polyphenol found in grapes and wine, has been found to pharmacologically precondition the heart in nitric oxide (NO)-dependent manner. In the vascular system, NO functions as an endogenous inhibitor of leukocyte chemotaxis, adherence, and activation. The present study was designed to determine if resveratrol, through NO, can block the proadhesive molecules generated in the ischemic reperfused myocardium. Isolated hearts were prepared from properly anesthetized rats, and mounted on a Langendorff apparatus. The hearts were randomly assigned to one of the three groups: (i) control, (ii) resveratrol, and (iii) resveratrol + NG-nitro-L-arginine ethyl ester (L-NAME). The hearts were perfused in the absence (n = 6) or presence of 10 micromol/L resveratrol (n=6) or resveratrol + L-NAME (n = 6) for 15 min. All the hearts were then subjected to 30 min ischemia followed by 2 h of reperfusion. Ventricular function was monitored, infarct size and apoptotic cell death measured, and the proadhesive molecules and malonaldehyde formation determined in the perfusate. Resveratrol significantly improved postischemic ventricular function and reduced myocardial infarct size compared to the non-treated control group. The amount of proadhesive molecules including soluble intracellular adhesion molecule-1 (sICAM-1), endothelial leukocyte adhesion molecule-1 (sE-Selectin) and vascular cell adhesion molecule-1 (sVCAM-1) were each significantly decreased during reperfusion in the resveratrol group. L-NAME, a NO blocker, completely abolished such beneficial effects of resveratrol. The results support an anti-inflammatory action of resveratrol through a NO-dependent mechanism.

Adult rats were treated for ten days with capsaicin or with NaCl 0.9% directly injected into the lateral cerebral ventricles through a surgically implanted cannula. A third group of rats was implanted with the same cannula but did not receive any treatment. The food intake and the body weight were recorded for at least six weeks after stopping the treatment. The animals were always kept at constant ambient temperature of 22 °C. The body weight of the capsaicin-treated group was reduced by the treatment, and showed a regular but lower degree of recovery trend than the control groups after the treatment period. In fact the capsaicin treated animals never reached the body weight of the controls. Nevertheless, food intake did not significantly vary after the capsaicin treatment. On the basis of these and previous findings, we can assume that capsaicin injected into the cerebral ventricles to rats kept at constant ambient temperature can acts on hypothalamic neurons, but a permanent action on metabolic pathways can not be excluded.

The expression pattern of the pannexin2 protein (Px2) in healthy and ischemized brains of adult rats was investigated. A polyclonal antibody for rat Px2 was generated in chicken and purified for affinity. This antibody was used to study by Western blot, Enzyme-Linked Immunosorbent Assay, and immunohistochemistry, the expression pattern of Px2 in healthy brain of adult rats and in the hippocampus of rats submitted to bilateral clamping of carotid arteries for 20 min, followed by different times of reperfusion (I/R) (8 h, 24 h, 48 h, 72 h, 14 days and 30 days). Immunohistochemical studies visualized the wide and complex expression pattern of Px2 in the healthy brain. All Px2(+) positive cells were neurons which also showed no puncta on their cellular membranes. Both pyramidal cells and interneurons, the majority of which were positive to parvalbumin, were stained in healthy hippocampus. The number of Px2 interneurons in the hippocampus showed a progressive reduction at successive time intervals after I/R, with a negative peak of about -40% after 72 h from I/R. Interneurons which were positive for both Px2 and parvalbumin, represented about the 85% of all parvalbumin cells stained in the hippocampus. This percentage rested grossly unmodified at different time intervals after I/R in spite of the progressive neuronal depletion. Concomitantly, an intense astrogliosis occurred in the hippocampus. Most of the astroglial cells expressed de novo and for a transient time (from 24 h to 14 days from I/R), Px2. Primary co-cultures of hippocampal neurons and astrocytes were submitted to transient ischemia-like injury. This set of experiments further confirmed the in vivo results by showing that Px2 is de novo and transiently expressed in astroglial cells following a transient ischemia-like injury. These results suggested the expression of Px2 in the astrocytes may be induced either from injured neurons or by biochemical pathways internal to the astrocyte itself. In conclusion, our results showed the transient expression of Px2 in astrocytes of reactive gliosis occurring in the hippocampus following I/R injury. We hypothesize that Px2 expression in astrocytes following an ischemic insult is principally involved in the formation of hemichannels for the release of signaling molecules devoted to influence the cellular metabolism and the redox status of the surrounding environment.

Recent studies have documented that grapes and grape juices are equally cardioprotective as red wine. The existing reports implicate that the skin and seeds of the grapes containing polyphenolic antioxidants are instrumental for the cardioprotective properties of grapes. The present study examines if the flesh of grapes also possesses any cardioprotective abilities. Three groups of randomly selected rats were fed, water only (control), flesh of the grapes (2.5 mg/kg b. wt.) or the skins (2.5 mg/kg b. wt.) for 30 days. At the end of the 30 days, isolated perfused hearts were made ischemic for 30 min followed by 2 h of reperfusion in the working mode. The results demonstrated that both flesh and skin of the grapes could protect the hearts from ischemic reperfusion injury as evidenced by improved postischemic ventricular recovery and reduced myocardial infarct size. High performance liquid chromatography (HPLC) revealed that skin and flesh contained comparative amounts of glucose, fructose, tartaric acid, malic acid, shikimic acid, and trans-caftaric acid. In addition, the flesh contained reduced amounts (compared to skin) of cis-coutaric, trans-coutaric, caffeic, p-coumaric, cinnamics, and catechin/epicatechin. Total polyphenolic index was also lower in flesh compared to skin. The anthocyanins were present exclusively in the skin. Electron paramagnetic resonance (EPR) spectrometry of hydroxy radicals indicated that both flesh and skins possessed equal amount of ROS scavenging activities. Total malonaldehyde content in the heart was reduced comparatively with either flesh or skin. The results indicate for the first time that the flesh of grapes are equally cardioprotective as skin, and antioxidant potential of skin and flesh of grapes are comparable with each other despite of the fact that flesh does not possess any anthocyanin activities.

MTT (3-(4, 5-dimethyl-2-thiazolyl)-2, 5-dihphenyltetrazolium bromide) assay is a widely used method to assess cell viability and proliferation. MTT is readily taken up by cells and enzymatically reduced to formazan, a dark compound which accumulates in cytoplasmic granules. Formazan is later eliminated by the cell by a mechanisms often indicated as exocytosis, that produces characteristic needle-like aggregates on the cell surface. The shape of formazan aggregates and the rate of exocytosis change in the presence of bioactive amyloid beta peptides (Abeta) and cholesterol. Though the cellular mechanisms involved in MTT reduction have been extensively investigated, the exact nature of formazan granules and the process of exocytosis are still obscure. Using Nile Red, which stains differentially neutral and polar lipids, and a fluorescent analog of cholesterol (NBD-cholesterol), we found that formazan localized in lipid droplets, consistent with the lipophilic nature of formazan. However, formazan granules and aggregates were also found to form after killing cells with paraformaldehyde fixation. Moreover, formazan aggregates were also obtained in cell-free media, using ascorbic acid to reduce MTT. The density and shape of formazan aggregates obtained in cell-free media was sensitive to cholesterol and Abeta. In cells, electron microscopy failed to detect the presence of secretory vesicles, but revealed unusual fibers of 50 nm of diameter extending throughout the cytoplasm. Taken together, these findings suggest that formazan efflux is driven by physico-chemical interactions at molecular level without involving higher cytological mechanisms.

The expression pattern of pannexin1, a gene coding for a protein that forms gap junction channels, was studied as both mRNA and protein in the CNS of adult mouse. Pannexin1 was widely expressed in the CNS by neuronal cell types but not glial cells, except for Bergmann glial cells of the cerebellar cortex. Cells positive to Ca-binding proteins, principally parvalbumin, but also calbindin and calretinin, as well as glutamate decarboxylase 67 kDa isoform, were pannexin1-positive. Pannexin1 labeling was found in cells which are known to exhibit spontaneous and synchronous discharge, such as neurons of the inferior olivary complex and the reticular thalamic nucleus, and also in neurons whose electrical activity is not coupled with neighboring cells, such as motoneurons of the spinal cord. The analysis of cellular localization showed puncta that surrounded cell bodies (e.g. the pyramidal cells of hippocampus) or restricted areas inside the cell bodies (e.g. the spinal motoneurons). In Bergmann glial cells the staining was present as fine grains that covered a large part of the cellular surface. Pannexin1 stained cells that previous studies have reported as expressing connexin36, another protein forming gap junction channels. Thus, it was possible that these two proteins could be integrated in the same functions. Since connexin36 expression levels change after seizures, we examined the expression of both pannexin1 and connexin36 in cerebral cortex, hippocampus, cerebellum and brain stem at different time intervals (2, 4 and 8 h) after i.p. injection of 4-aminopyridine, which resulted in systemic seizures. The only modification of the expression levels observed in this study concerned the progressive decrement of the connexin36 in the hippocampus, while pannexin1 expression was unchanged. This finding suggested that pannexin1 and connexin36 are involved in different functional roles or that they are expressed in different cell types and that only those expressing the Cx36 are induced to apoptosis by epileptic seizures.

A new chemical named parrodienes has been extracted from parrots' plumage. From the chemical point of view, parrodienes are polyunsaturated aldehydes similar to carotenoids. On the basis of this similarity we organized some biological experiments to evaluate the inhibition of lipoperoxidation of cell membranes induced by CCl4, protection against ultraviolet rays, anti-inflammatory activity and protection from an increase of ornithine-decarboxylase as marker of tumoral skin alteration. The results of these experiments showed that unsaturated dienes (parrodienes) play an important role on the inhibition and prevention of many biological processes that are at the basis of different pathological disorders.

The antioxidant activity of a novel series of derivatives with a carotenoid-like structure was studied. These derivatives have recently been isolated chemically as a result of studies on the pigments present in a particular species of birds, namely parrots. These novel derivatives, which are also called parrodienes, have been proved to possess interesting biological properties that differ from those that carotenoids are known to have. The objective of this study was to demonstrate the ability of these novel compounds to inhibit the formation of reactive oxygen species, especially their ability to block the formation of hydroxyl radicals, which are among the most reactive products of oxygen reactions and which produce the greatest damage to cells and tissues. The technique used to assess this antioxidant capacity of parrodienes was electron paramagnetic resonance, which allows direct assessment of inhibition of hydroxyl radical formation (.OH). The results show that these derivatives, especially octatriene, are able to exert evident antioxidant activity, thus confirming that their antioxidant properties are important for their biological activity.

The present study demonstrates that intrathecal injection of interleukin-1 (IL-1) in rats at a dose of 50 pg or 500 pg induced a significant hyperalgesic effect in the hot-plate test. The hyperalgesia or the altered nociceptive responses were not considered to be the result of sensitization to the hot plate, since the nociceptive alteration caused by intrathecal administration of IL-1 stopped after 20 min. The results suggest that IL-1 can affect pain responsiveness in a dose-dependent manner and that it is able to modulate neuronal functions. Taken together, our findings and the data from the literature suggest that IL-1-induced hyperalgesia is related not only to the route of administration but also to the algesia testing method used.

Rats were taught to self-administer beta-endorphin (0.1 microgram or 0.5 microgram/microliter) or NaCl 9% by pressing a lever that activated a pump connected with a cannula implanted in the lateral cerebral ventricle (icv). The pump delivered 1 microliter at each lever pressing. After a training period of 2 weeks, the self-injection behaviour was studied before, during and after nociceptive stimulation. In response to a nociceptive stimulation, 4 rats increased their self-injection of beta-endorphin at 0.5 microgram/microliter per injection. This effect is specific for beta-endorphin since under identical conditions 6 rats did not increase the injection of isotonic NaCl saline solution. Another 6 rats did not increase their self-injection during nociceptive electrical stimulation and the post-nociceptive period when the dose of beta-endorphin was 0.1 microgram/microliter per injection. However these animals self-administered significantly higher levels of beta-endorphin during the pre-control period. Also studied were the acute effects of 10 micrograms of icv beta-endorphin on tail-flick latency in sec. The acute administration of 10 micrograms of beta-endorphin induced a long-lasting analgesia. The results show that the rats increased beta-endorphin self-administration during the pre-control period when the dose was 0.1 microgram/microliter and during the nociceptive stimulation period when the dose was 0.5 microgram/microliter. In the former case the self-administration had the profile of a voluntary doping drug intake, in the latter case the profile was that of an antalgic self-medication.

Two or three minutes after intracerebroventricular (i.c.v.) injection of Tween 80 plus ethanol as vehicles for capsaicin, strong convulsive movements occurred in the treated rats; they twisted and turned, dashed themselves against their cage and all died. Tween 80 in saline without ethanol also produced convulsions and death in all the rats treated. Capsaicin dissolved in the vehicle seemed to furnish protection against such death. Moreover, when capsaicin in Tween 80 was administered i.c.v. 10 min before the Tween vehicle it prevented the death which would have been caused by the i.c.v. vehicle. Thus a new effect is added to those already discovered in the numerous pharmacological studies on capsaicin.

Although eggplants are known to be part of a healthy diet, the effects of this fruit on cardioprotection are not known. The present study examined the role of raw and grilled eggplants on cardioprotection using an isolated perfusion heart model. The animals were fed freeze-dried products of either raw or grilled eggplants for 30 days. After 30 days, isolated working hearts were subjected to 30 min ischemia followed by 2 h of reperfusion. Left ventricular function was monitored, and myocardial infarct size and cardiomyocyte apoptosis were assessed. To determine the antioxidant function of eggplants, their DPPH scavenging ability were determined, and polyphenolic components, especially nasunin content, were determined. The chemical composition of raw and grilled eggplants were determined in order to examine whether grilling was associated with major changes in their composition. The results of this study demonstrated eggplants as containing potent cardioprotective compounds judging by their ability to increase left ventricular function, and reduce myocardial infarct size and cardiomyocyte apoptosis. However, there was no difference in cardioprotective ability between the raw and grilled products. The antioxidant vitamins, including vitamin A, vitamin C and β-carotene, were lower and some of the polyphenolic components, especially nasunin content, were higher in grilled eggplants, but they were unable to demonstrate better cardioprotective properties compared to the raw fruit.

Microbial infections are a major problem in tumor-bearing and in immunocompromised patients. In such conditions it is of paramount importance to know the possible interactions between anti-tumor and antimicrobial drugs. In the present work we investigated the relationship between Ceftazidime and Mitoxantrone. Ceftazidime and Mitoxantrone were tested alone and in combination for antibacterial activity against different strains of Gram- and Gram+ bacteria. The cytotoxic effect of combination Mitoxantrone-Ceftazidime was determined in cultured P388 leukemia cells. No interference with the antibacterial activity of Ceftazidime or with the cytotoxic activity of Mitoxantrone was observed.

Dactimicin is a new pseudo-disaccharidic aminoglycosidic antibiotic produced by Dactylosporangium matsuzakiense. The aim of the present research was to evaluate the pharmacokinetics of dactimicin intramuscularly administered, at the dosage of 20 mg/kg, in male Sprague-Dawley rats with an average b.w. of 200-220 g. Dactimicin levels were assessed by using a microbiological method (agar diffusion) employing Bacillus subtilis ATCC 6633 as test organism. Samples were collected immediately before and 0.25, 0.50, 1, 1.15 and 2 h after drug administration. The mean peak serum level, reached after 15 min, was 33.6 micrograms/ml (range 30.3-40 micrograms/ml); T1/2 beta was 0.42 h; extrapolated AUC was 26.8 mg h/l.

The transmethylating activity of ATCA was directly evaluated by administering ATCA 14C to a group of rats. The radioactivity associated with the labile methyl group was recovered in microsomal phospholipids, and in particular in the phosphatidylethanolamine and phosphatidylcholine fractions. These biochemical data on the transmethylating activity of the drug confirm a previous indirect demonstration of the protective activity of ATCA in experimental intoxications and elucidate its mechanisms.

Acute intracerebroventricular injection of 25 micrograms capsaicin or 40 micrograms substance P in isotonic saline elicited approximately similar effects on the micturition reflex, but capsaicin had twice as much effect as substance P. This effect is specific, since acute intracerebroventricular injection of isotonic saline did not produce the micturition reflex. It can be hypothesized that capsaicin and substance P may act on the brain micturition centers directly or by mediation of neuropeptides such as tachykinins, but other hypotheses are also made.

In this work, monoolein-based cubosomes were doped with two fluorescent probes, namely, fluoresce in and dansyl, properly modified with a hydrocarbon chain to increase their encapsulation efficiency within the monoolein palisade. The same nanocarriers were also loaded, with quercetin, a hydrophobic molecule with potential anticancer activity. Particularly, the cubosomes doped with the modified fluorescein probe were successfully exploited for single living cell, imaging. The physicochemical and photophysical characterizations reported here, along with the well-known ability of cubosomes in hosting molecules with pharmaceutical interest, strongly encourage the use of these innovative fluorescent nanocarriers for theranostic purposes.