5,868 research outputs found
Extracellular cysteine in connexins: Role as redox sensors
Indexación: Scopus.Connexin-based channels comprise hemichannels and gap junction channels. The opening of hemichannels allow for the flux of ions and molecules from the extracellular space into the cell and vice versa. Similarly, the opening of gap junction channels permits the diffusional exchange of ions and molecules between the cytoplasm and contacting cells. The controlled opening of hemichannels has been associated with several physiological cellular processes; thereby unregulated hemichannel activity may induce loss of cellular homeostasis and cell death. Hemichannel activity can be regulated through several mechanisms, such as phosphorylation, divalent cations and changes in membrane potential. Additionally, it was recently postulated that redox molecules could modify hemichannels properties in vitro. However, the molecular mechanism by which redox molecules interact with hemichannels is poorly understood. In this work, we discuss the current knowledge on connexin redox regulation and we propose the hypothesis that extracellular cysteines could be important for sensing changes in redox potential. Future studies on this topic will offer new insight into hemichannel function, thereby expanding the understanding of the contribution of hemichannels to disease progression.http://journal.frontiersin.org/article/10.3389/fphys.2016.00001/ful
Bioclimatology, structure, and conservation perspectives of Quercus pyrenaica, Acer opalus subsp. Granatensis, and Corylus avellana deciduous forests on Mediterranean bioclimate in the South-Central part of the Iberian Peninsula
The plant variability in the southern Iberian Peninsula consists of around 3500 different taxa due to its high bioclimatic, geographic, and geological diversity. The deciduous forests in the southern Iberian Peninsula are located in regions with topographies and specific bioclimatic conditions that allow for the survival of taxa that are typical of cooler and wetter bioclimatic regions and therefore represent the relict evidence of colder and more humid paleoclimatic conditions. The floristic composition of 421 samples of deciduous forests in the south-central part of the Iberian Peninsula were analyzed. The ecological importance index (IVI) was calculated, where the most important tree species were Quercuspyrenaica, Aceropalus subsp. Granatensis, and Corylusavellana. These species are uncommon in the south-central part of the Iberian Peninsula, forming forests of little extension. An analysis of the vertical distribution of the species (stratum) shows that the majority of the species of stratum 3 (hemicriptophics, camephytes, geophites, and nanophanerophytes) are characteristic of deciduous forests, and their presence is positively correlated with high values of bioclimatic variables related to humidity and presence of water in the soil (nemoral environments), while they are negatively correlated with high values of bioclimatic variables related to high temperatures, evapotranspiration, and aridity. This work demonstrates that several characteristic deciduous forest taxa are more vulnerable to disappearance due to the loss of their nemoral conditions caused by gaps in the tree or shrub canopy. These gaps lead to an increase in evapotranspiration, excess insolation, and a consequent loss of water and humidity in the microclimatic conditions.info:eu-repo/semantics/publishedVersio
Uso de los tra amientos termico e no termico (alta presion hidrostatica) para la inactivación de enzimas bacterianas metaloproteases presentes en la degradación de leche.
El estudio de la aplicación de la tecnologÃa de alta presión en el tratamiento de la leche para la inactivación de las enzimas proteolÃticas puede proporcionar un producto con alta calidad y salubridad diferencial, capaz de investir en un aumento del consumo y de valor agregado, con el fin de beneficiarse de la cadena de producción, con impactos económicos y sociales
Estudo morfoanatômico comparativo entre a poaia (Psychotria ipecacuanha (Brot.) Stokes - Rubiaceae) obtida da região Amazônica (habitat original) e proveniente de processo biotecnológico submetida a diferentes tratamentos de interceptação da radiação solar.
A poaia ou ipeca (Psychotria ipecacuanha (Brot.) Stokes.-Rubiaceae) apesar de seu valor farmacológico e sócio-econômico é cada vez menos freqüente no seu habitat. O objetivo deste trabalho foi realizar o estudo comparativo dos aspectos morfoanatômicos entre a espécie originária da Amazônia Brasileira e a obtida in vitro submetidas a diferentes tratamentos de interceptação de radiação solar, visando, desta forma, dar suporte a estudos com fins de preservação, cultivo, validação farmacognóstica/farmacopéica e ampliar o conhecimento biotecnológico desta espécie. A espécie nativa foi obtida de fragmento de mata (fase vegetativa) e empregada para micropropagação através do cultivo in vitro de fragmentos de segmentos internodais sobre meio de cultivo Murashige & Skoog com o regulador de crescimento BAP (2,0 mg/l de meio). Obtiveram-se plântulas que foram transferidas para casa de vegetação por 2 anos sob dois tipos de ambiente e três diferentes tratamentos de interceptação da radiação solar. Foi feito o estudo morfoanatômico, analisado estatisticamente. Verifica-se que as plantas originadas por processo biotecnológico e submetidas aos diferentes tratamentos apresentam morfologia semelhante à planta nativa, no entanto constatou-se um maior número de raÃzes secundárias, não há diferença significativa entre larguras e comprimentos de folhas, comprimento de raÃzes, estÃpulas, peso de raÃzes e rizomas. Mas, observou-se diferença estatÃstica no comprimento do caule em relação à nativa
Periodontitis and Hypertension: Is the Association Causal?
High blood pressure (BP) and periodontitis are two highly prevalent conditions worldwide with a significant impact on cardiovascular disease (CVD) complications. Poor periodontal health is associated with increased prevalence of hypertension and may have an influence on BP control. Risk factors such as older age, male gender, non-Caucasian ethnicity, smoking, overweight/obesity, diabetes, low socioeconomic status, and poor education have been considered the common denominators underpinning this relationship. However, recent evidence indicates that the association between periodontitis and hypertension is independent of common risk factors and may in fact be causal in nature. Low-grade systemic inflammation and redox imbalance, in particular, represent the major underlying mechanisms in this relationship. Neutrophil dysfunction, imbalance in T cell subtypes, oral-gut dysbiosis, hyperexpression of proinflammatory genes, and increased sympathetic outflow are some of the pathogenetic events involved. In addition, novel findings indicate that common genetic bases might shape the immune profile towards this clinical phenotype, offering a rationale for potential therapeutic and prevention strategies of public health interest. This review summarizes recent advances, knowledge gaps and possible future directions in the field
The Bohm Interpretation of Quantum Cosmology
I make a review on the aplications of the Bohm-De Broglie interpretation of
quantum mechanics to quantum cosmology. In the framework of minisuperspaces
models, I show how quantum cosmological effects in Bohm's view can avoid the
initial singularity, isotropize the Universe, and even be a cause for the
present observed acceleration of the Universe. In the general case, we
enumerate the possible structures of quantum space and time.Comment: 28 pages, 1 figure, contribution to the James Cushing festschrift to
appear in Foundations of Physic
Periodontal therapy and treatment of hypertension-alternative to the pharmacological approach. A systematic review and meta-analysis
Aim: Quantitative comparison of the effects of intensive (IPT) or conventional (CPT) periodontal treatment on arterial blood pressure, endothelial function and inflammatory/metabolic biomarkers. / Materials and methods: A systematic search was conducted to identify randomized controlled trials (RCT) of IPT (supra and subgingival instrumentation). Eight RCTs were included in the meta-analysis. Difference in change of systolic blood pressure (SBP) and diastolic blood pressure (DBP) before and after IPT or CPT were the primary outcomes. The secondary outcomes included: endothelial function and selected inflammatory/anti-inflammatory (CRP, IL-6, IL-10, IFN-γ) and metabolic biomarkers (HDL, LDL, TGs). / Results: The overall effect estimates (pooled Weighted Mean Difference (WMD)) of the primary outcome for SBP and DBP was −4.3 mmHg [95%CI: −9.10–0.48], p = 0.08 and −3.16 mmHg [95%CI: −6.51–0.19], p = 0.06 respectively. These studies were characterized by high heterogeneity. Therefore, random effects model for meta-analysis was performed. Sub-group analyses confirmed statistically significant reduction in SBP [WMD = −11.41 mmHg (95%CI: −13.66, −9.15) P < 0.00001] and DBP [WMD = −8.43 mmHg (95%CI: −10.96,−5.91)P < 0.00001] after IPT vs CPT among prehypertensive/hypertensive patients, while this was not observed in normotensive individuals. The meta-analyses showed significant reductions in CRP and improvement of endothelial function following IPT at all analysed timepoints. / Conclusions: IPT leads to improvement of the cardiovascular health in hypertensive and prehypertensive individuals
Peripheral Microangiopathy Changes in Pulmonary Arterial Hypertension Related to Systemic Sclerosis: Data From a Multicenter Observational Study
Systemic sclerosis (SSc) is a connective tissue disease characterized by immune-system alterations, fibrosis involving the skin and internal organs and diffuse microangiopathy. Pulmonary arterial hypertension (PAH) is a severe complication of SSc affecting about 10-15% of the patients and it is a leading cause of mortality. Due to the devastating nature of SSc-PAH, there is a clear need to systematically adopt appropriate screening programs. Nail fold videocapillaroscopy (NVC) studies have shown a more severe peripheral microvascular dysfunction in SSc patients with PAH suggesting that abnormalities in peripheral microcirculation may correlate with pulmonary microangiopathy. This is a cross-sectional study involving four tertiary University Rheumatology Units in the Center-North of Italy. Seventy patients, 35 adults with SSc and PAH confirmed by RHC (F/M 34/1; median age 65.2 ± 8.9 SD yrs), and 35 SSc patients without PAH were enrolled (F/M 3471; median age 63.3 ± 10.3 SD yrs). Clinical, laboratoristic and instrumental data were collected and NVC was performed in all patient. Specific NVC parameters were evaluated and a semi-quantitative rating scale was adopted to score these changes. Finally, patients were distributed into the suitable NVC pattern belonging to the scleroderma pattern. Our aim was to compare the peripheral microangiopathy changes in SSc patients with and without PAH, and to investigate the relationship between NVC findings and the main hemodynamic parameters of pulmonary vasculopathy. Patients with SSc-PAH+ showed a significant higher frequency of interstitial lung disease (ILD). No significant differences regarding clinical and laboratoristic parameters were observed. NVC abnormalities, avascular areas were more frequent in SSc patients with PAH, respect to those without (p = 0.03), and capillary density was significantly lower when considering grade 3 (p = 0.02). A higher NVC semiquantitative mean was found in SSc-PAH+ patients and a greater rate of the "late" pattern was detected in SSc-PAH+ subjects in respect to PAH- (57.1% vs. 25.7%) (p = 0.03). A significant correlations between pulmonary pressure values (sPAP by TTE and mPAP by RHC) and the capillary density (Spearman's rho 0.35, p = 0.04 for both). Our findings provide additional evidence to the literature data, confirming that a higher degree of peripheral nailfold microangiopathy is more common in SSc-PAH patients, and further strengthening the concept that NVC changes may run parallel with similar abnormalities inside pulmonary microcirculation
Arterial stiffness, endothelial and cognitive function in subjects with type 2 diabetes in accordance with absence or presence of diabetic foot syndrome.
BACKGROUND:
Endothelial dysfunction is an early marker of cardiovascular disease so endothelial and arterial stiffness indexes are good indicators of vascular health. We aimed to assess whether the presence of diabetic foot is associated with arterial stiffness and endothelial function impairment.
METHODS:
We studied 50 subjects with type 2 diabetes mellitus and diabetic foot syndrome (DFS) compared to 50 diabetic subjects without diabetic foot, and 53 patients without diabetes mellitus, by means of the mini mental state examination (MMSE) administered to evaluate cognitive performance. Carotid-femoral pulse wave velocity (PWV) and augmentation index (Aix) were also evaluated by Applanation tonometry (SphygmoCor version 7.1), and the RH-PAT data were digitally analyzed online by Endo-PAT2000 using reactive hyperemia index (RHI) values.
RESULTS:
In comparison to diabetic subjects without diabetic foot the subjects with diabetic foot had higher mean values of PWV, lower mean values of RHI, and lower mean MMSE. At multinomial logistic regression PWV and RHI were significantly associated with diabetic foot presence, whereas ROC curve analysis had good sensitivity and specificity in arterial PWV and RHI for diabetic foot presence.
CONCLUSIONS:
Pulse wave velocity and augmentation index, mean RHI values, and mean MMSE were effective indicators of diabetic foot. Future research could address these issues by means of longitudinal studies to evaluate cardiovascular event incidence in relation to arterial stiffness, endothelial and cognitive markers
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