Effects of dobutamine on gut mucosal nitric oxide production during endotoxic shock in rabbits

Background: Dobutamine is the agent of choice for increasing cardiac output during myocardial depression in humans with septic shock. Studies have shown that beta-adrenoceptor agonists influence nitric oxide generation, probably by modulating cyclic adenosine monophosphate. We investigated the effects of dobutamine on the systemic and luminal gut release of nitric oxide during endotoxic shock in rabbits. Materials/Methods: Twenty anesthetized and ventilated New Zealand rabbits received placebo or intravenous lipopolysaccharide with or without dobutamine (5 mu g/kg/min). Ultrasonic flow probes placed around the superior mesenteric artery and the abdominal aorta continously estimated the flow. A segment from the ileum was isolated and perfused, and scrum nitrate/nitrite levels were measured in the perfusate solution and the serum every hour. Results: The mean arterial pressure decreased with statistical significance in the lipopolysaccharide group but not in the lipopolysaccharide/dobutamine group. The abdominal aortic flow decreased statistically significantly after lipopolysaccharide administration in both groups but recovered to base-line in the lipopolysaccharide/dobutamine group. The flow in the superior mesenteric artery was statistically significantly higher in the lipopolysaccharide/dobutamine group than in the lipopolysaccharide group at 2 hours. The serum nitrate/nitrite levels were higher in the lipopolysaccharide group and lower in the lipopolysaccharide/dobutamine group than those in the control group. The gut luminal perfusate serum nitrate/nitric level was higher in the lipopolysaccharide group than in the lipopolysaccharide/dobutamine group. Conclusions: Dobutamine can decrease total and intestinal nitric oxide production in vivo. Those effects seem to be inversely proportional to the changes in blood flow.

Modulation of human cardiac function through 4 beta-adrenoceptor populations

In human heart there is now evidence for the involvement of four beta-adrenoceptor populations, three identical to the recombinant beta(1)-, beta(2)- and beta(3)-adrenoceptors, and a fourth as yet uncloned putative beta-adrenoceptor population, which we designate provisionally as the cardiac putative beta(4)-adrenoceptor. This review described novel features of beta-adrenoceptors as modulators of cardiac systolic and diastolic function. We also discuss evidence for modulation by unoccupied beta(1)- and beta(2)-adrenoceptors. Human cardiac and recombinant beta(1)- and beta(2)-adrenoceptors are both mainly coupled to adenylyl cyclase through Gs protein, the latter more tightly than the former. Activation of both human beta(1)- and beta(2)-adrenoceptors not only increases cardiac force during systole but also hastens relaxation through cyclic AMP-dependent phosphorylation of phospholamban and troponin I, thereby facilitating diastolic function. Furthermore, both beta(1) and beta(2)-adrenoceptors can mediate experimental arrhythmias in human cardiac preparations elicited by noradrenaline and adrenaline. Human ventricular beta(3)-adrenoceptors appear to be coupled to a pertussis toxin-sensitive protein (Gi?). beta(3)-Adrenoceptor-selective agonists shorten the action potential and cause cardiodepression, suggesting direct coupling of a Gi protein to a K+ channel. In a variety of species, including man, cardiac putative beta(4)-adrenoceptors mediate cardiostimulant effects of non-conventional partial agonists, i.e. high affinity beta(1)- and beta(2)-adrenoceptor blockers that cause agonist effects at concentrations considerably higher than those that block these receptors. Putative beta(4)-adrenoceptors appear to be coupled positively to a cyclic AMP-dependent cascade and can undergo some desensitisation.

Spin-orbit mixing and nephelauxetic effects in the electronic spectra of nickel(II)-encapsulating complexes involving nitrogen and sulfur donors

A study of spin-orbit mixing and nephelauxetic effects in the electronic spectra of nickel(II)-encapsulating complexes involving mixed nitrogen and sulfur donors is reported. As the number of sulfur donors is systematically varied through the series [Ni(N6-xSx)](2+) (x = 0-6), the spin-forbidden (3)A(2)g --> E-1(g) and (3)A(2g) --> (1)A(1g) transitions undergo a considerable reduction in energy whereas the spin-allowed transitions are relatively unchanged. The [Ni(diAMN(6)sar)](2+) and [Ni(AMN(5)Ssar)](2+) complexes exhibit an unusual band shape for the (3)A(2g) --> T-3(2g) transition which is shown to arise from spin-orbit mixing of the E spin-orbit levels associated with the E-1(g) and T-3(2g) states. A significant differential nephelauxetic effect also arises from the covalency differences between the t(2g) and e(g) orbitals with the result that no single set of Racah B and C interelectron repulsion parameters adequately fit the observed spectra. Using a differential covalency ligand-field model, the spectral transitions are successfully reproduced with three independent variables corresponding to 10Dq and the covalency parameters f(t) and f(e), associated with the t(2g) and e(g) orbitals, respectively. The small decrease in f(t) from unity is largely attributed to central-field covalency effects whereas the dramatic reduction in f(e) with increasing number of sulfur donors is a direct consequence of the increased metal-ligand covalency associated with the sulfur donors. Covalency differences between the t(2g) and e(g) orbitals also result in larger 10Dq values than those obtained simply from the energy of the (3)A(2g) --> T-3(2g) spin-allowed transition.

Guanosine promotes B16F10 melanoma cell differentiation through PKC-ERK 1/2 pathway

Malignant melanoma is one of the most lethal cancers. Nowadays, several anti-melanoma therapies have been employed. However, the poor prognosis and/or the increased toxicity of those treatments clearly demonstrate the requirement of searching for new drugs or novel combined chemotherapeutic protocols, contemplating both effectiveness and low toxicity. Guanosine (Guo) has been used in combination with acriflavina to potentiate the latter`s antitumor activity, through still unknown mechanisms. Here, we show that Guo induces B16F10 melanoma cell differentiation, attested by growth arrest, dendrite-like outgrowth and increased melanogenesis, and also reduced motility. A sustained ERK 1/2 phosphorylation was observed after Guo treatment and ERK inhibition led to blockage of dendritogenesis. Intracellular cyclic AMP was not involved in ERK activation, since its levels remained unchanged. Protein kinase C (PKC), in contrast to phospholipase C (PLC), inhibition completely prevented ERK activation. While the classical melanoma differentiation agent forskolin activates cAMP-PKA-Raf-MEK-ERK pathway in B16F10 cells, here we suggest that a cAMP-independent, PKC-ERK axis is involved in Guo-induced B16F10 differentiation. Altogether, our results show that Guo acts as a differentiating agent, with cytostatic rather than cytotoxic properties, leading to a decreased melanoma malignancy. Thus, we propose that Guo may be envisaged in combination with lower doses of conventional anti-melanoma drugs, in an attempt to prevent or diminish their adverse effects. (c) 2008 Elsevier Ireland Ltd. All rights reserved.

Endometriosis of the ureter and bladder are not associated diseases

Objective: To verify whether bladder and ureter endometriosis had the same clinical features and disease behavior. Design: Case-control study. Setting: Multidisciplinary group in Sao Paulo, Brazil. Patient(s): A total of 690 patients were submitted to laparoscopy with histologically diagnosis of endometriosis between July 1999 and December 2006. Twelve of these patients had lesions affecting the ureter and 26 had lesions affecting the bladder. A control group consisted of 652 patients in whom endometriosis was not affecting either the ureter or the bladder. Intervention(s): None. Main Outcome Measure(s): Clinical and surgical features of patients with ureteral or bladder endometriosis. Result(s): No patients with ureteral endometriosis had lesions affecting the bladder. Compared with the control group, patients with ureteral endometriosis had more advanced disease (Stages III and IV) according to the American Society of Reproductive Medicine (ASRM) staging classification (100% vs. 65.5%); they also had more retrocervical (83.3% vs. 21.6%) and rectum-sigmoid lesions (91.7% vs. 17.9%). Compared with the control group, more patients with bladder endometriosis had cyclic dysuria and/or hematuria (34.6% vs. 9.8%), more advanced stages of the disease (88.4% vs. 65.5%), and an association with endometriosis of the rectum-sigmoid (65.3% vs. 17.9%). Conclusion(s): Ureter endometriosis is not associated with the bladder disease; however, it is associated with advanced ASRM stages and with retrocervical and rectum-sigmoid lesions. (Fertil Steril (R) 2009;91:1662-7. (C)2009 by American Society for Reproductive Medicine.)

Observations on the Female Internal Reproductive Organs of the Brown Howler Monkey (Alouatta guariba clamitans)

Alouatta guariba clamitans (brown howler monkey) is an endemic primate from the southeastern Brazil tropical forests, classified as near threatened by the IUCN Red List 2007. The genus Aloualta is one of the most difficult New World monkeys to breed and rear in captivity. In this study we examined the macroscopic and histological aspects of the female genital tract of wild brown howler monkeys to provide baseline information for future reproduction research. The anatomical relationship between the vagina, uterus, broad ligament, oviducts and ovaries are those of a typical primate reproductive tract. The fundic portion of the uterus is globoid, the cervix is well developed, which confers to the uterus an elongated shape, and the vagina is a long flattened channel. Histological analysis conducted in females in the follicular phase revealed large quantities of interstitial luteinized tissue in the ovaries, a stratified nonkeratinized vaginal epithelium, lack of glands in the vaginal mucosa and simple tubular endometrial glands. The observed anatomical features should be considered in the adaptation and application of assisted reproductive techniques aimed at improving captive reproduction for species conservation. Am. J. Primatol. 71:145-152, 2009. (C) 2008 Wiley-Liss, Inc.

Autoantibodies as predictors of biological therapy for early rheumatoid arthritis

Introduction: The association between serological markers with the need of biological therapy for early rheumatoid arthritis (ERA) is not known, with few available data addressing this question. Objectives: To prospectively evaluate a cohort of patients with ERA (less than 12 months of symptoms) in order to determine the possible association between serological markers (rheumatoid factor (RF), anti-cyclic citrullinated peptide antibodies (anti-CCP), and citrullinated anti-vimentin (anti-Sa) with parameters of therapeutic outcome (this later defined by the need of introducing biological therapy). Patients and methods: Forty patients with early RA were evaluated at the time of diagnosis and have been followed for 3 years, in use of standardized therapeutic treatment. Demographic and clinical data were recorded, as well as serology tests (ELISA) for RF (IgM, IgG and IgA), anti-CCP (CCP2, CCP3 and CCP3.1) and anti-Sa in the initial evaluation and at 3, 6, 12, 18, 24 and 36 months of follow-up. As outcomes of the RA development, the need or not for biological therapy during the follow-up period were considered. Comparisons were made through the Student t test, mixed-effects regression analysis and analysis of variance (significance level of 5%). Results: The mean age was 45 (+/- 12) years; a female predominance was observed (90%). At the time of diagnosis, RF was observed in 50% of cases (RF IgA - 42%, RF IgG - 30% and RF IgM - 50%), anti-CCP in 50% (no difference between CCP2, CCP3 and CCP3. 1) and anti-Sa in 10%. After 3 years, no change in the RF prevalence neither in the anti-CCP was observed, but the anti-Sa increased to 17.5% (p = 0.001). Biological therapy was necessary in 22.5% of patients. The mean RF IgA and anti-CCP 2 levels during the 3 years were higher among patients who needed biological therapy (p <0.05 for both). Conclusion: Higher titles of RF and anti-CCP over time were associated with the need for biological therapy.

Influence of ventilatory settings on static and functional haemodynamic parameters during experimental hypovolaemia

Background and objective The influence of ventilatory settings on static and functional haemodynamic parameters during mechanical ventilation is not completely known. The purpose of this study was to evaluate the effect of positive end-expiratory pressure, tidal volume and inspiratory to expiratory time ratio variations on haemodynamic parameters during haemorrhage and after transfusion of shed blood. Methods Ten anaesthetized pigs were instrumented and mechanically ventilated with a tidal volume of 8 ml kg(-1), a positive end-expiratory pressure of 5 cmH(2)O and an inspiratory to expiratory ratio of 1 : 2. Then, they were submitted in a random order to different ventilatory settings (tidal volume 16 ml kg(-1), positive end-expiratory pressure 15 cmH(2)O or inspiratory to expiratory time ratio 2: 1). Functional and static haemodynamic parameters (central venous pressure, pulmonary artery occlusion pressure, right ventricular end-diastolic volume and pulse pressure variation) were evaluated at baseline, during hypovolaemia (withdrawal of 20% of estimated blood volume) and after an infusion of withdrawn blood (posttransfusion). Results During baseline, a positive end-expiratory pressure of 15cmH(2)O significantly increased pulmonary artery occlusion pressure from 14.6 +/- 1.6 mmHg to 17.4 +/- 1.7 mmHg (P<0.001) and pulse pressure variation from 15.8 +/- 8.5% to 25.3 +/- 9.5% (P<0.001). High tidal volume increased pulse pressure variation from 15.8 8.5% to 31.6 +/- 10.4% (P<0.001), and an inspiratory to expiratory time ratio of 2: 1 significantly increased only central venous pressure. During hypovolaemia, high positive end-expiratory pressure influenced all studied variables, and high tidal volume strongly increased pulse pressure variation (40.5 +/- 12.4% pre vs. 84.2 +/- 19.1 % post, P<0.001). The inversion of the inspiratory to expiratory time ratio only slightly increased filling pressures during hypovolaemia, without without affecting pulse pressure variation or right ventricle end-diastolic volume. Conclusion We concluded that pulse pressure variation measurement is influenced by cyclic variations in intrathoracic pressure, such as those caused by augmentations in tidal volume. The increase in mean airway pressure caused by positive end-expiratory pressure affects cardiac filling pressures and also pulse pressure variation, although to a lesser extent. Inversion of the inspiratory to expiratory time ratio does not induce significant changes in static and functional haemodynamic parameters. Eur J Anaesthesiol 26:66-72 (c) 2009 European Society of Anaesthesiology.

Mandibular appliance modulates condylar growth through integrins

Functional orthopedic therapy corrects growth discrepancies between the maxilla and mandible, possibly through postural changes in the musculature and modulation of the mandibular condylar cartilage growth. Using Wistar rats, we tested the hypothesis that chondrocytes respond to forces generated by a mandibular propulsor appliance by changes in gene expression, and that integrins are important mediators in this response. Immunohistochemical analyses demonstrated that the use of the appliance for different periods of time modulated the expression of fibronectin, alpha 5 and alpha v integrin subunits, as well as cell proliferation in the cartilage. In vitro, cyclic distension of condylar cartilage-derived cells increased fibronectin mRNA, as well as Insulinlike Growth Factor-I and II mRNA and cell proliferation. A peptide containing the Arginine-Glycine-Asparagine sequence (RGD), the main cell-binding sequence in fibronectin, blocked almost all these effects, confirming that force itself modulates the growth of the rat condylar cartilage, and that RGD-binding integrins participate in mechanotransduction.

PHOSPHODIESTERASE-4 INHIBITION REDUCES PROTEOLYSIS AND ATROGENES EXPRESSION IN RAT SKELETAL MUSCLES

Phosphodiesterase (PDE) inhibition reduces skeletal muscle atrophy, but the underlying molecular mechanism remains unclear. We used microdialysis to investigate the effects of different PDE inhibitors on interstitial tyrosine concentration as well as proteolytic activity and atrogenes expression in isolated rat muscle. Rolipram, a PDE-4-selective inhibitor, reduced the interstitial tyrosine concentration and rates of muscle protein degradation. The rolipram-induced muscle cAMP increase was accompanied by a decrease in ubiquitin proteasome system (UPS) activity and atrogin-1 mRNA, a ubiquitin-ligase involved in muscle atrophy. This effect was not associated with Akt phosphorylation but was partially blocked by a protein kinase A inhibitor. Fasting increased atrogin-1, MuRF-1 and LC3b expression, and these effects were markedly suppressed by rolipram. Our data suggest that activation of cAMP signaling by PDE-4 blockade leads to inhibition of UPS activity and atrogenes expression independently of Akt. These findings are important for identifying novel approaches to attenuate muscle atrophy. Muscle Nerve 44: 371-381, 2011

Evolutionary transition to freshwater by ancestral marine palaemonids: evidence from osmoregulation in a tide pool shrimp

The transition from marine/brackish waters to freshwater habitats constitutes a severe osmotic and ionic challenge, and successful invasion has demanded the selection of morphological, physiological, biochemical and behavioral adaptations. We evaluated short-term (1 to 12 h exposure) and long-term (5 d acclimation), anisosmotic extracellular (osmolality, [Na(+), Cl(-)]) and long-term isosmotic intracellular osmoregulatory capability in Palaemon northropi, a neotropical intertidal shrimp. F northropi survives well and osmo- and ionoregulates strongly during short- and long-term exposure to 5-45 parts per thousand salinity, consistent with its rocky tide pool habitat subject to cyclic salinity fluctuations, Muscle total free amino acid (FAA) concentrations decreased by 63% in shrimp acclimated to 5%. salinity, revealing a role in hypoosmotic cell volume regulation; this decrease is mainly a consequence of diminished glycine, arginine and proline. Total FAA contributed 31% to muscle intracellular osmolality at 20 parts per thousand, an isosmotic salinity, and decreased to 13% after acclimation to 5 parts per thousand. Gill and nerve tissue FAA concentrations remained unaltered. These tissue-specific responses reflect efficient anisosmotic and anisoionic extracellular regulatory mechanisms, and reveal the dependence of muscle tissue on intracellular osmotic effectors. FAA concentration is higher in P. northropi than in diadromous and hololimnetic palaemonids, confirming muscle FAA concentration as a good parameter to evaluate the degree of adaptation to dilute media. The osmoregulatory capability of P. northropi may reflect the potential physiological capacity of ancestral marine palaemonids to penetrate into dilute media, and reveals the importance of evaluating osmoregulatory processes in endeavors to comprehend the invasion of dilute media by ancestral marine crustaceans.

Differential gene expression of peripheral blood mononuclear cells from rheumatoid arthritis patients may discriminate immunogenetic, pathogenic and treatment features

This study aimed to evaluate the association between the differential gene expression profiling of peripheral blood mononuclear cells of rheumatoid arthritis patients with their immunogenetic (human leucocyte antigen shared-epitope, HLA-SE), autoimmune response [anti-cyclic citrullinated peptide (CCP) antibodies], disease activity score (DAS-28) and treatment (disease-modifying antirheumatic drugs and tumour necrosis factor blocker) features. Total RNA samples were copied into Cy3-labelled complementary DNA probes, hybridized onto a glass slide microarray containing 4500 human IMAGE complementary DNA target sequences. The Cy3-monocolour microarray images from patients were quantified and normalized. Analysis of the data using the significance analysis of microarrays algorithm together with a Venn diagram allowed the identification of shared and of exclusively modulated genes, according to patient features. Thirteen genes were exclusively associated with the presence of HLA-SE alleles, whose major biological function was related to signal transduction, phosphorylation and apoptosis. Ninety-one genes were associated with disease activity, being involved in signal transduction, apoptosis, response to stress and DNA damage. One hundred and one genes were associated with the presence of anti-CCP antibodies, being involved in signal transduction, cell proliferation and apoptosis. Twenty-eight genes were associated with tumour necrosis factor blocker treatment, being involved in intracellular signalling cascade, phosphorylation and protein transport. Some of these genes had been previously associated with rheumatoid arthritis pathogenesis, whereas others were unveiled for future research.

Sildenafil inhibits duodenal contractility via activation of the NO-K+ channel pathway

Phosphodiesterase type-5 (PDE5) specifically cleaves cyclic guanosine monophosphate (cGMP), a key intracellular secondary messenger. The PDE5 inhibitor sildenafil is a well-known vasodilator that also has gastrointestinal myorelaxant properties. In the present study, we further investigated sildenafil-induced myorelaxation in rat isolated duodenum, assessing its interaction with nitric oxide (NO) synthase and K+ channel opening. The spontaneous contractions of duodenal strips were reversibly inhibited by sildenafil (0.1-300 mu M) in a concentration-dependent manner [mean (95% confidence interval); EC50 = 6.8 (2.7-17.3) mu M]. The sildenafil-induced myorelaxation was significantly decreased by the NO synthase inhibitor N-nitro-L-arginine methyl ester [increasing the EC50 value to 41.9 (26.1-67.3) mu M]. Sodium nitroprusside or forskolin pretreatments enhanced the sildenafil-induced myorelaxation. In isolated strips pretreated with BaCl2 (0.2 mM), 4-aminopyridine (4-AP, 3 mM), or glybenclamide (1 mu M), the sildenafil-induced EC50 value was significantly increased to 32.8 (19.1-56.4), 27.1 (15.2-48.3) and 20.1 (16.4-24.7) mu M, respectively. Minoxidil (50 mu M) or diazoxide (100 mu M) also significantly attenuated the sildenafil-induced potency. In conclusion, the NO synthase/cyclic nucleotide pathway activation is involved in sildenafil-induced inhibition of spontaneous duodenal contractions. Its pharmacological action seems to be influenced by K+ channel opening, especially the voltage-sensitive ones, being inhibited by 4-AP and K-ATP channels, sensitive to glybenclamide.

Effects of nitric oxide on neutrophil influx depends on the tissue: role of leukotriene B(4) and adhesion molecules

Background and purpose: We investigated the effect of nitric oxide synthase (NOS) inhibition on polymorphonuclear cell (PMN) influx in zymosan or lipopolysaccharide (LPS)-induced arthritis and peritonitis. Experimental approach: Wistar rats received intra-articular (i.art.) zymosan (30-1000 mu g) or LPS (1-10 mu g). Swiss C57/Bl6 mice genetically deficient in intercellular adhesion molecule-1 (ICAM-1(-/-)) or in beta(2)-integrin (beta(2)-integrin(-/-)) received zymosan either i.art. or i.p. PMN counts, leukotriene B(4) (LTB(4)), tumour necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) levels were measured in joint and peritoneal exudates. Groups received the NOS inhibitors N(G)-nitro-L-arginine methyl ester (LN), nitro-L-arginine, N-[3-(aminomemethyl) benzyl] acetamide or aminoguanidine, prior to zymosan or LPS, given i.p. or s.c. in the arthritis and peritonitis experiments respectively. A group of rats received LN locally (i.art. or i.p.), 30 min prior to 1 mg zymosan i.art. Key results: Systemic or local NOS inhibition significantly prevented PMN migration in arthritis while increasing it in peritonitis, regardless of stimuli, concentration of NOS inhibitors and species. NOS inhibition did not alter TNF-alpha and IL-10 but decreased LTB(4) in zymosan-induced arthritis. LN administration significantly inhibited PMN influx into the joints of ICAM-1(-/-) and beta(2)-integrin(-/-) mice with zymosan-arthritis, while not altering PMN influx into the peritoneum of mice with zymosan-peritonitis. Conclusions and implications: Nitric oxide has a dual modulatory role on PMN influx into joint and peritoneal cavities that is stimulus-and species-independent. Differences in local release of LTB(4) and in expression of ICAM-1 and beta(2)-integrin account for this dual role of NO on PMN migration.

Role of the bed nucleus of the stria terminalis in the cardiovascular responses to acute restraint stress in rats

The aim of this work was to test the hypothesis that the bed nucleus of the stria terminalis (BST) and noradrenergic neurotransmission therein mediate cardiovascular responses to acute restraint stress in rats. Bilateral microinjection of the non-specific synaptic blocker CoCl2 (0.1nmol/100nl) into the BST enhanced the heart rate (HR) increase associated with acute restraint without affecting the blood pressure increase, indicating that synapses within the BST influence restraint-evoked HR changes. BST pretreatment with the selective 1-adrenoceptor antagonist WB4101 (15nmol/100nl) caused similar effects to cobalt, indicating that local noradrenergic neurotransmission mediates the BST inhibitory influence on restraint-related HR responses. BST treatment with equimolar doses of the 2-adrenoceptor antagonist RX821002 or the -adrenoceptor antagonist propranolol did not affect restraint-related cardiovascular responses, reinforcing the inference that 1-adrenoceptors mediate the BST-related inhibitory influence on HR responses. Microinjection of WB4101 into the BST of rats pretreated intravenously with the anticholinergic drug homatropine methyl bromide (0.2mg/kg) did not affect restraint-related cardiovascular responses, indicating that the inhibitory influence of the BST on the restraint-evoked HR increase could be related to an increase in parasympathetic activity. Thus, our results suggest an inhibitory influence of the BST on the HR increase evoked by restraint stress, and that this is mediated by local 1-adrenoceptors. The results also indicate that such an inhibitory influence is a result of parasympathetic activation.