Acute and chronic captopril, but not prazosin or nifedipine, normalize alterations in adrenergic intracellular Ca2+ handling observed in the mesenteric arterial tree of spontaneously hypertensive rats

The effect of hypertension and acute (36-h) or chronic (from age 6 to 16 weeks) antihypertensive treatment with prazosin (2 mg kg(-1) per day), nifedipine (50 mg kg(-1) per day), or captopril (50 mg kg(-1) per day) on Ca2+ mobilization due to alpha1-adrenoceptor activation was analyzed in functional studies using arterial rings [four conductance/distributing vessels: aorta, main mesenteric, iliac, and tail arteries and two resistance vessels; first and second small mesenteric artery branches obtained from spontaneously hypertensive rats (SHR, 6 and 16 weeks old) and age-matched Wistar Kyoto rats (WKY)]. Maximal response to noradrenaline in the presence of extracellular Ca2+ is not affected by hypertension or by the antihypertensive treatment. The extracellular Ca2+-independent contractile responses increased with age in iliac, tail, and small mesenteric arteries (SMA) and were further increased in SHR in SMA from both young and adult animals and in the main mesenteric artery of adult SHR. In main mesenteric artery, this increased contraction in SHR was associated with a higher increase in cytosolic [Ca2+] mobilized by noradrenaline without changes in the total stored Ca2+. Acute or chronic treatment with captopril abolished the differences observed between WKY and SHR in the noradrenaline-induced contraction in mesenteric arteries loaded in Ca2+-free medium. In contrast, animals acutely treated with prazosin or chronically treated with either prazosin or nifedipine exhibit the same differences in Ca2+ handling than untreated rats. In conclusion, these differences are not a consequence of increased blood pressure but precede it and can only be normalized by inhibition of the rennin-angiotensin system.     

Estándares de calidad asistencial para las consultas de enfermería en reumatología

BackgroundNursing clinics in rheumatology (NCR) are organizational models in the field of nursing care. There are various NCR models, but there is no consensus on its operational definition. Our objective is to develop quality standards to define and characterize a NCR.MethodTwo-round Delphi method. The panel consisted of 67 experts: Rheumatologists and nurses of the nursing working group of the Spanish Society of Rheumatology (SSR). The Delphi questionnaire was developed after a literature and experience review from previous SSR projects. The questionnaire consists of 7 sections: general considerations, standards of structure, process, treatment and monitoring, health education, training and research and quality of care. Each item was scored from 1 (least important) to 9 (most important) or by assigning a number (e.g., waiting days). The degree of agreement among the experts was categorized according to the coefficient of variation (CoV) between very high (CoV≤25%) and very low (CoV>100%).ResultsThe second round questionnaire (182 items) was answered by 46 panelists (34 rheumatologists and 12 nurses). A very important agreement was reached on the general standards of structure, process, treatment and monitoring, health education and quality of care. Less agreement was observed on standards related to training time, number of recommended nurses’ research projects and publications.ConclusionThe standards developed in this study would be useful for establishing desirable quality standards of structure and process, and criteria for clinical work, research and teaching that can be used to develop and evaluate the NCRs.     

Incorporation of reconstituted acetylcholine receptors from Torpedo into the Xenopus oocyte membrane.

Xenopus oocytes are a valuable aid for studying the molecular structure and function of ionic channels and neurotransmitter receptors. Their use has recently been extended by the demonstration that oocytes can incorporate foreign membranes carrying preassembled receptors and channels. Here we show that when reconstituted in an artificial lipid matrix and injected into Xenopus oocytes, purified nicotinic acetylcholine receptors are efficiently inserted into the plasma membrane, where they form "clusters" of receptors that retain their native properties. This constitutes an innovative approach that, besides allowing the analyses of membrane fusion processes, is also a powerful technique for studying the characteristics and regulation of many membrane proteins (with their native stoichiometry and configuration) upon reinsertion into the membrane of a very convenient host cell system.     

Comparison of tocilizumab as monotherapy or with add-on disease-modifying antirheumatic drugs in patients with rheumatoid arthritis and inadequate responses to previous treatments: an open-label study close to clinical practice

This was an exploratory analysis comparing the safety and efficacy of tocilizumab monotherapy with those of tocilizumab in combination with disease-modifying anti-rheumatic drugs (DMARDs). Data were from a single-arm, nonrandomized, open-label, 24-week study in patients with rheumatoid arthritis in which patients with inadequate responses to DMARDs or tumor necrosis factor-α inhibitors received tocilizumab 8 mg/kg intravenously every 4 weeks plus methotrexate/other DMARD(s) combination therapy. If they were intolerant of methotrexate/other DMARD, patients received tocilizumab monotherapy. Effectiveness endpoints included American College of Rheumatology (ACR) responses (ACR20/50/70/90) and disease activity score using 28 joints (DAS28). Of 1,681 patients, 239 received tocilizumab monotherapy, and 1,442 received combination therapy. Methotrexate was the most common DMARD (79 %) used in combination therapy. The frequency of adverse events (AEs), serious AEs, and AEs leading to withdrawal were similar between tocilizumab monotherapy (82.4, 7.9, and 5.4 %, respectively) and combination therapy (76.6, 7.8, and 5.1 %, respectively). No differences in ACR20/50/70/90 responses were observed between treatment groups (66.9 %/43.5 %/23.8 %/10.0 % vs 66.9 %/47.2 %/26.8 %/8.5 %, respectively; p > 0.12 for all individual comparisons, including ACR50 propensity score analyses). The decrease in DAS28 was also similar between treatment groups (mean ± standard deviation: −3.41 ± 1.49 for tocilizumab monotherapy vs −3.43 ± 1.43 for combination therapy; p > 0.33 all analyses, including propensity score analyses). Tocilizumab had a comparable safety profile, and was similarly effective, when used as monotherapy or in combination with DMARDs in a broad population of patients with rheumatoid arthritis.

     

Translocation of Microbenthic Algal Assemblages Used for In Situ Analysis of Metal Pollution in Rivers

Effects of metal pollution from a zinc factory on microbenthic algal communities were assessed in three neighboring streams on the Dutch-Belgian border. Diatom species composition was experimentally related to water quality by transferring racks with colonized glass discs from a polluted stream to a reference stream and vice versa. The succession of species and the changes in biomass and metal accumulation were measured during experiments in spring, autumn, and winter. Metal concentrations and dry weight in translocated biofilms tended to conform with those in local biofilms within an incubation time of 14 to 18 days. Bray-Curtis similarity values from the different communities indicated that diatom communities responded more completely to the metal-polluted conditions than to the reference water quality. Cymbella minuta, Diatoma vulgare var. ehrenbergii, Navicula sp., and Melosira varians had a lower percentage in assemblages placed in the metal-polluted streams. In contrast, Pinnularia sp. and Neidium ampliatum decreased in assemblages from the polluted streams that were transferred to the reference stream. Achnanthes minutissima and Navicula seminulum (N. atomus) proliferated on any translocation, possibly reflecting an opportunistic strategy and a high tolerance for Zn and Cd. The behavior of the species in relation to metal pollution generally accorded with observations in the literature. However, it seems that metal tolerance is not the only selective factor, and other ecological variables may also influence the composition of microphytobenthic communities. Received: 30 July 1998/Accepted: 5 January 1999     

Characterization of membrane-bound cyclic nucleotide phosphodiesterases from bovine aortic smooth muscle.

This study reports the isolation and characterization of cyclic nucleotide phosphodiesterases (PDEs) associated with membrane fraction in comparison to cytosolic forms from bovine aorta. DEAE-Sephacel chromatography of a solubilized membrane fraction from a homogenate, prepared under isotonic conditions in the presence of protease inhibitors, yielded one major peak of PDE activity that specifically hydrolyzed cAMP and was not stimulated by calmodulin: It appeared to contain two subtypes of PDE. The first subtype belonged to the cyclic GMP (cGMP)-inhibited PDE family, (PDE III): It had an apparent Km value of 0.4 microM and was potently inhibited by cGMP, LY186126, and cilostamide. The second was a rolipram-sensitive PDE form (PDE IV) that had an apparent Km value for cAMP hydrolysis of 1.1 microM, was selectively inhibited by rolipram and denbufylline, and was insensitive to cGMP. These two forms had kinetic and pharmacologic profiles similar to those resolved by DEAE-Sephacel from the cytosolic fraction (105,000 g supernatant). In addition, DEAE-Sephacel chromatography of the cytosolic fraction revealed another peak of PDE activity that could be resolved with high-performance liquid chromatography (HPLC) into a calmodulin-sensitive form that preferentially hydrolyzed cGMP (PDE I) and a calmodulin-insensitive form that specifically hydrolyzed cGMP (PDE V). The presence of a PDE III in vascular smooth muscle that exhibited similarities to the cGMP-inhibited PDE from cardiac tissues, the target of several new cardiotonic agents, suggests that a single mechanism of action may account for the cardiotonic and vasodilating properties of PDE III inhibitors.     

A SiC microdevice for the minimally invasive monitoring of ischemia in living tissues

Monitoring of ischemia in living tissues is a field of increasing interest in many clinical settings. In this work we report for the first time anywhere the development of needle-shaped, minimally-invasive impedance probes based on silicon carbide (SiC) substrates. An in-vitro comparison of these new devices with Si-based impedance probes demonstrates that their effective operation range extends up to the 100 kHz range, thus allowing a wide-spectrum multi-frequency analysis of impedance modulus and phase angle. Furthermore, we show that, when applied to in-vivo settings, this kind of analysis yields to an accurate monitoring of ischemia, while making possible the application of more robust mathematical methods for the study of impedance in living tissues.