Ultrasonic Sensor: A Fast and Non-Destructive System to Measure the Viscosity and Density of Molecular Fluids.

This study presents the design and development of an ultrasonic sensor as a fundamental tool for characterizing the properties of fluids and biofluids. The analysis primarily focuses on measuring the electrical parameters of the system, which correlate with the density and viscosity of the solutions, in sample volumes of microliters and with high temporal resolution (up to 1 data point per second). The use of this sensor allows the fast and non-destructive evaluation of the viscosity and density of fluids deposited on its free surface. The measurements are based on obtaining the impedance versus frequency curve and the phase difference curve (between current and voltage) versus frequency. In this way, characteristic parameters of the transducer, such as the resonance frequency, phase, minimum impedance, and the quality factor of the resonant system, can characterize variations in density and viscosity in the fluid under study. The results obtained revealed the sensor's ability to identify two parameters sensitive to viscosity and two parameters sensitive to density. As a proof of concept, the unfolding of the bovine albumin protein was studied, resulting in a curve that reflects its unfolding kinetics in the presence of urea.

Inhibition of glutathione reductase uncovers the activation of NADPH-inhibited glucose-6-phosphate dehydrogenase.

Eggleston and Krebs pointed to a paradox in glucose-6-phosphate dehydrogenase (G6PD) regulating process that has not yet been solved, and which originated the term "fine regulation" of G6PD and, therefore, of oxidative phase of pentose phosphate pathway (OPPP). The paradox is that, in basal-like conditions, the activity of G6PD evaluated "in vitro" is very low or nearly null because of the potent inhibiting effect exerted by NADPH, a coenzyme whose concentration in the cell is much higher than that of the substrate NADP+ . However, "in vivo," flow through OPPP occurs in basal conditions. Eggleston and Krebs speculated on the possible existence of a system that would reverse the inhibition by NADPH. Such system would involve oxidized glutathione and exclude the participation of glutathione reductase (GR). The present work confirms the experimental results obtained by Eggleston and Krebs and proves that oxidized glutathione (GSSG) in the absence of NADPH is a direct inhibitor of G6PD. In the presence of GSSG, the G6PD activity recovery system suggested can be observed when GR is previously inhibited by alkylating agents. An unknown element with a molecular weight ranging between 12 and 50 kDa has been found to reverse part of G6PD inhibition by NADPH.

Usefulness of the Wisconsin and CaPTHUS indices for predicting multiglandular disease in patients with primary hyperparathyroidism in a southern European population.

BACKGROUND: Focused parathyroidectomy is a safe technique for the treatment of primary hyperparathyroidism. The CaPTHUS score and the Wisconsin index are preoperative diagnostic tools designed to distinguish between single- and multigland disease. The aim of the study is to evaluate the usefulness of these models for predicting multiglandular disease in a European population. METHODS: Retrospective review of a database of patients operated upon for primary hyperparathyroidism at a referral center. The sensitivity, specificity, positive and negative predictive values, and reliability of both scores for the prediction of multiglandular disease, were calculated. Receiver operating characteristic (ROC) curves were constructed to assess the sensitivity and specificity of CaPTHUS score and Wisconsin Index for predicting single-gland disease. A level of P<0.05 was accepted as significant. RESULTS: Two hundred and eighty-one patients who underwent successful surgery from January 2001 to December 2018 were included. Single-gland disease was detected in 92.5%, and 73.7% had a CaPTHUS score of ≥3. The sensitivity, specificity, positive and negative predictive values of this model for predicting single-gland disease with a score of ≥3 were 76.9%, 66.7%, 96.6%, and 18.9% respectively. The area under the curve value of the CaPTHUS score for predicting single-gland disease was 0.74. A Wisconsin Index >2,000 and an excised gland weight above one gram presented a positive predictive value for single-gland disease of 92.5%. CONCLUSIONS: Despite the good performance of both scales, the established cut-off points did not definitively rule out parathyroid multiglandular disease in our population. In cases with a minimal suspicion of this condition, additional intraoperative techniques must be used, or bilateral neck explorations should be performed.

Development and validation of a new model for predicting hypocalcaemia after total thyroidectomy: the NuGra model.

BACKGROUND: Hypocalcaemia is the most frequent complication after total thyroidectomy. Finding a method for its early detection has become a priority. A single-center prospective cohort study was conducted to identify risk factors for postoperative hypocalcaemia, develop an early detection model, and test its validity in a different group of patients. METHODS: The sample was composed of patients who underwent a total thyroidectomy between May 2012 and September 2015. Demographic, clinical, laboratory, and surgical data were collected. The incidence of hypocalcaemia and permanent hypoparathyroidism was calculated. Bivariate and multivariate analysis identified several independent predictors of hypocalcaemia, which were used to design a predictive model. The validity of the model was subsequently tested in a different cohort. Area under the ROC curve (AUROC) was calculated to determine its predictive power. RESULTS: The study and validation groups included 352 and 118 patients, respectively. Seventy-three patients developed laboratory-confirmed hypocalcaemia (20.7%), and symptomatic in 43 (12.2%). Multivariate analysis confirmed as independent predictors of hypocalcaemia the higher number of parathyroid glands identified [OR 1.41(0.98, 2.02); p = 0.063] and pre-to-postoperative gradient of parathormone decline [OR 1.06(1.04, 1.08); p < 0.001]. Based on these variables, the NuGra (Number of parathyroid glands identified-Gradient of decline) model was developed for predicting laboratory-confirmed hypocalcaemia. Its predictive power was high (AUROC 0.902, CI 0.857-0.947) for the study and the validation group (AUROC 0.956, CI 0.919-0.993). CONCLUSIONS: A higher number of parathyroid glands identified and a higher gradient of parathormone decline are risk factors for post-thyroidectomy hypocalcaemia. The NuGra model is useful for early prediction of individual risk for hypocalcaemia.

Prophylaxis of venous thromboembolism in general surgery in Spain. Analysis of a national survey. / Profilaxis del tromboembolismo venoso en cirugía general en España. Análisis de una encuesta nacional.

INTRODUCTION: Venous thromboembolism (VTE) represents a serious postoperative complication that can be prevented by adequate thromboprophylaxis. Surveys provide relevant information about clinician's attitudes and preferences regarding VTE prophylaxis. METHODS: Transversal, descriptive study based on a survey sent to general surgeons members of the Spanish Association of Surgeons (AEC), that included 31 questions regarding postoperative VTE and its prevention, as well as three clinical scenarios. RESULTS: 530 surgeons, 21.8% of the 2,429 invited by electronic mail to participate, completed the survey. Most of the answering clinicians work on in big teaching hospitals, and 28.5% are residents. VTE represents a serious problem for 28% of participants. Although 81% consider that their knowledge on the prevention of postoperative VTE is adequate, a similar percentage recognizes the need for further education. The vast majority (98.7%) use low molecular weight heparins, which are considered the most effective and safe modality, followed by mechanical methods. The Caprini risk assessment score is used by 81% of surgeons, who usually start pharmacological prophylaxis preoperatively. However, there are remarkable differences in the dosing of heparins, timing of initiation, and duration, especially in non-oncologic surgical patients. CONCLUSIONS: Most Spanish surgeons are interested in the prevention of postoperative VTE. Overall, the level of knowledge on thromboprophylaxis is adequate. However, our results indicate that there is a need for better education on relevant practical aspects of prophylaxis that could be achieved by incorporating recommendations from recent guidelines to local hospital-based protocols.

Form of presentation, natural history and course of postoperative venous thromboembolism in patients operated on for pelvic and abdominal cancer. Analysis of the RIETE registry. / Forma de presentación, historia natural y evolución de la enfermedad tromboembólica venosa postoperatoria en pacientes operados por cáncer abdominal y pélvico. Análisis del registro RIETE.

INTRODUCTION: Venous thromboembolism (VTE) represents a serious complication after oncologic surgery. Recent studies have shown that the risk of VTE persists several weeks after surgery. This study assesses the form of presentation and time course of VTE after abdominal and pelvic cancer surgery. METHODS: Prospective, multicenter, observational study that analyzes data from an international registry (RIETE) that includes consecutive patients with symptomatic VTE. Our study assesses the form and time of presentation of postoperative VTE, as well as main outcomes, in patients operated for abdominopelvic cancer 8 weeks prior to VTE diagnosis. Variables related to the presentation of VTE after hospital discharge are identified. RESULTS: Out of the 766 analyzed patients with VTE, 395 (52%) presented pulmonary embolism (PE). Most VTE cases (84%) were detected after the first postoperative week, and 38% after one month. Among patients with VTE in the first postoperative week, 70% presented PE. VTE presented after hospital discharge in 54% of cases. Colorectal, urologic, and gynecologic tumors, the use of radiotherapy, and blood hemoglobin levels were independently associated with VTE diagnosis after hospital discharge. Complications (thrombosis recurrence, bleeding, and death) occurred in 34% of patients with VTE detected before hospital discharge, compared to 24% in VTE after hospital discharge (P<0.01). CONCLUSIONS: VTE occurs after hospital discharge in most patients, particularly in those operated for colorectal, urologic, and gynecologic cancer. Pulmonary embolism is more frequent in patients who develop early VTE, who also have worse prognosis.

The regulation of the pentose phosphate pathway: Remember Krebs.

The changes in gene expression and posttranslational modifications of enzymes are comprised in the concept of "coarse control" of the oxidative phase of the pentose phosphate pathway. However, these changes are slow in its implementation. The defensive mechanism against oxidative stress requires a most rapid response, impossible to achieve with coarse regulation systems. Recently, it has been suggested that a quick acceleration mechanism of G6PD activity could be produced by the reduction of NADPH-inhibition of G6PD. The hypothesis opens new ways on possible mechanisms for rapid modulation that could be in accordance with results obtained in the 70s by Krebs. These results seemed outdated in view of the subsequent research. However, they deserve to be re-assessed at present.

Hypercarnivorous apex predator could provide ecosystem services by dispersing seeds.

Large "hypercarnivorous" felids are recognized for their role as apex predators and hence as key elements in food webs and ecosystem functioning through competition and depredation. Here we show that cougars (Puma concolor), one of the largest and the most widely ranging apex felid predators with a strictly carnivorous diet, could also be effective secondary long distance seed dispersers, potentially establishing direct and non-herbivore mediated interactions with plant species at the bottom of the food web. Cougars accidently ingest and disseminate large amounts of seeds (31,678 seeds in 123 scats) of plant species initially consumed by their main prey, the Eared Dove Zenaida auriculata. The germination potential of seeds for the three plant species most abundantly found in cougar scats (19,570 seeds) was not significantly different from that observed in seeds obtained from dove gizzards, indicating that seed passage through cougar guts did not affect seed germination. Considering the estimated cougar density in our study area, dispersal of seeds by cougars could allow a mean, annual seed spread of ~5,000 seeds per km(2). Our results demonstrate that strictly carnivorous, felid predators could have broad and overlooked ecological functions related to ecosystem structuring and functioning.

Recurrence of liver metastases from colorectal cancer and repeat liver resection.

OBJECTIVE: The purpose of this study was to assess the resectability and effectiveness of repeat hepatectomy for relapsing liver metastases of colorectal origin in terms of morbidity, mortality, overall survival, and disease-free survival. METHODS: A retrospective study was performed on a prospective cohort of patients with colorectal liver metastases who underwent repeat surgery at Hospital Universitario San Cecilio, Granada (Spain), from March 2003 to June 2013. Primary outcome variables included survival and morbidity within 30 days post-surgery. RESULTS: A total of 147 patients with colorectal liver metastases underwent surgical excision during the study period; 61 patients had liver recurrence, and 34 of these received repeat surgery. The overall survival rate at 5 and 10 years for resected patients (n=27/34) was 48% and 48%. Mean hospital stay was 8.9 ± 3.5 days, morbidity was 9%, and mortality was 0%. CONCLUSION: Repeat liver resection for colorectal liver metastases is a safe, effective surgical procedure whose results are similar to those obtained after initial liver resection.

The regulation of the oxidative phase of the pentose phosphate pathway: new answers to old problems.

There is a paradox in the oxidizing phase of the phosphate pentose pathway that has not yet been solved. The flow through the pathway is reduced in basal conditions; however, it must rise notably when a NADPH supplement is required. The paradox consists of the strong inhibition that the NADPH exerts on the both dehydrogenases of the pathway, especially on the regulating enzyme glucose-6-phosphate dehydrogenase (G6PD). Theoretically, in anabolic situations, the increase of gene expression of G6PD and 6-phosphogluconate dehydrogenase can induce a rise in the production of NADPH, which would cause the immediate inhibition of the enzyme and a drastic flow reduction. However, increasing the flow through oxidative phase of the pentose phosphate pathway (OPPP) has been experimentally demonstrated in many physiological states. However, this situation will be resolved if the NADPH metabolized or otherwise sufficient NADPH is sequestered to relax the inhibition of the dehydrogenases of OPPP and to maintain high ratio of NADPH/NADP(+) needed to ensure the reducing environment of the cell cytoplasm and the contribution of NADPH for anabolic processes. In 1974, the presence of a protein capable of reversing the inhibition of G6PD by NADPH was detected; however, to date, this paradox remains undisclosed. This review deals with the possibility that such reverting action might be similar to the activity of a protein named HSCARG, which is responsible for the abduction of NADPH, thus keeping a portion of the coenzyme away from the catalytic action and, simultaneously, the immune response through the NF-κB (nuclear factor kappa light-chain enhancer of activated B cells) system. The model has many similarities with the hypothesis proposed some 40 years back on the reversion of G6PD inhibition by NADPH.

Are migrants health policies aimed at improving access to quality healthcare? An analysis of Spanish policies.

Although until April 2012, all Spanish citizens regardless of their origin, residence status and work situation were entitled to health care, available evidence suggested inadequate access for immigrants. Following the Aday and Andersen model, we conducted an analysis of policy elements that affect immigrants' access to health care in Spain, based on documentary analysis of national policies and selected regional policies related to migrant health care. Selected documents were (a) laws and plans in force at the time containing migrant health policies and (b) evaluations. The analysis included policy principles, objectives, strategies and evaluations. Results show that the national and regional policies analyzed are based on the principle that health care is a right granted to immigrants by law. These policies include strategies to facilitate access to health care, reducing barriers for entry to the system, for example simplifying requirements and raising awareness, but mostly they address the necessary qualities for services to be able to attend to a more diverse population, such as the adaptation of resources and programs, or improved communication and training. However, limited planning was identified in terms of their implementation, necessary resources and evaluation. In conclusion, the policies address relevant barriers of access for migrants and signal improvements in the health system's responsiveness, but reinforcement is required in order for them to be effectively implemented.

Robust GRBF static neurocontroller with switch logic for control of robot manipulators.

A new Gaussian radial basis function static neurocontroller is presented for stable adaptive tracking control. This is a two-stage controller acting in a supervisory fashion by means of a switch logic and allowing arbitration between a neural network (NN) and a robust proportional-derivative controller. The structure is intended to reduce the effects of the curse of dimensionality in multidimensional systems by fully exploiting the mechanical properties of the robot manipulator. A new factorization of the Coriolis/centripetal matrix is used, leading to an NN model that is much smaller than the dynamic ones. By resorting to the extended multivariate Shannon theorem and the computation of the effective bandwidth of the revolute robot manipulators, the network parameters are tuned. Stability and convergence properties are analyzed. This provides the assurance of reliability and effectiveness to make such controller viable. A robot manipulator with two degrees of freedom is employed to study the adaptive features of the neural control algorithm. Finally, the effectiveness of the proposed method is compared to the nonadaptive case.

After the Prestige oil spill modifications in NO production and other parameters related to the immune response were detected in hemocytes of Mytilus galloprovincialis.

In marine mollusks, many physiologic functions are regulated seasonally depending on such factors as the reproductive cycle or the presence of food. The synthesis of nitric oxide by hemocytes of Mytilus galloprovincialis is among the multiple physiologic actions in the immune response, and it is also affected by season. The maximal basal production of NO by hemocytes of M. galloprovincialis was detected in summer, whereas the minimum values were detected in winter. In winter, the presence of IL-2 induced an increase in NO production that was not detected in summer. Three months after the Prestige oil spill (November 2002), basal NO production by the hemocytes of mussels in the Galician coast showed a progressive decrease and stopping, both in summer and in winter. The characteristic increase of NO synthesis induced by IL-2 in winter also disappeared all through 2003 and 2004. The two different nitric oxide synthases previously identified by immunoblotting between 1999 and 2002 were undetectable in both 2003 and 2004. When comparing the data obtained during 2003 and 2004 to those obtained in previous years, an increase in the proportion of SH cells was detected. Also, these cells showed a higher sensitivity to apoptosis- and necrosis-inducing agents than in earlier years.

Implication of PKC in the seasonal variation of the immune response of the hemocytes of Mytilus galloprovincialis Lmk. and its role in interleukin-2-induced nitric oxide synthesis.

The hemocytes are the cells responsible for the immune response in marine mollusks. The role of NO in processes related to the activation of the hemocytes has turned out evident over the late years. In the case of the mussel Mytilus galloprovincialis Lmk., hemocyte NO basal production varies throughout the year, showing a maximum in summer and a minimum in winter. IL-2 reverts the low winter NO basal production through a process mediated by cAMP-dependent protein kinase and by an apparent side effect of protein kinase C. The seasonal variation of NO production in the presence of the PKC inhibitor bisindolylmaleimide (BSM) allows suggesting a model in which PKC would modulate the activity of the enzymes responsible for nitric oxide production.

In hemocytes from Mytilus galloprovincialis Lmk., treatment with corticotropin or growth factors conditions catecholamine release.

The cells in charge of the innate immune response in the sea mussel Mytilus galloprovincialis Lmk. are the hemocytes, which have the capacity to release catecholamines when subjected to stressing conditions. Hemocytes were kept in culture before stimulation. That is, their behaviour was not studied immediately after extraction from the mollusc, as happens in most studies. This avoids the interference and variability caused by the conditions in which mussels may be when collected. This work describes the great variability found in the pattern of catecholamine release when the hemocytes are stimulated with either corticotropins or growth factors. Dopamine, adrenaline and noradrenaline release differs with each of the inducers assayed, with stimulation time and with the season of hemocyte collection. One of the results presented is particularly remarkable; such is the great amount of adrenaline and noradrenaline released to the medium when the hemocytes obtained in summer are stimulated with transforming growth factor-beta1 (TGF-beta1) for 60 min.

Nitric oxide production by haemocytes from Mytilus galloprovincialis shows seasonal variations.

Nitric oxide (NO) has been identified as an important physiological modulator, with evidence of its role as a signalling molecule throughout the whole phylogenetic scale. In marine molluscs, it intervenes in processes related to the immune function of haemocytes. The presented results indicate that basal NO production by haemocytes of Mytilus galloprovincialis shows seasonal variations, with summer values statistically higher than those of winter. The presence of IL-2 increased NO production in winter. In summer, incubating the haemocytes with TNF-alpha for 6h slightly increased NO production. LPS, TGF-beta1 or PDGF did not induce significant effects on NO production by the haemocytes. Immunoblotting experiments detected two proteins that bind to vertebrate iNOS and eNOS antibodies, with different seasonal expression: the protein that binds to anti-iNOS antibody was expressed throughout the year, whereas the anti-eNOS antibody bound with a protein that was only detected in winter. IL-2 is suggested to start a signalling system dependent on the seasonal presence of winter protein. Such a system would activate the enzyme, thus favouring the higher NO production detected in winter.

An improved dynamic neurocontroller based on Christoffel symbols.

In this paper, a dynamic neurocontroller for positioning of robots based on static and parametric neural networks (NNs) has been developed. This controller is based on Christoffel symbols of first kind in order to carry out coriolis/centripetal matrix. Structural properties of robots and Kronecker product has been taken into account to develop NNs to approximate nonlinearities. The weight updating laws have been obtained from a nonlinear strategy based on Lyapunov energy that guarantees both stability and boundedness of signals and weights. The NN weights are tuned online with no "offline learning phase" and are initialized to zero. The neurocontroller improves the implementation with respect to other dynamic NNs used in the literature.

Implication of PKA and PKC in the activation of the haemocytes of Mytilus galloprovincialis Lmk by LPS and IL-2.

LPS and IL-2 play an essential role in the generation of the immune response in diverse eukaryotic species, as they provoke the activation of several pathways of signal transduction in macrophages. Among the kinases related to these pathways, PKA and the PKCs are some of the most important. In the haemolymph of the marine mussel Mytilus galloprovincialis Lmk, the cells responsible for the defence reactions are the haemocytes. These act as active phagocytes, and are able also to secrete humoral factors. The effect of the stimulation of the haemocytes with either LPS or IL-2 on the expression of both a Ca(2+)-independent PKC (p105) and a regulatory subunit (RII) of PKA found in mussel tissues are studied in this work. Also, the effect of inhibitors specific for these kinases on their expression and on their release of catecholamines is reported.

In vitro effects of LPS, IL-2, PDGF and CRF on haemocytes of Mytilus galloprovincialis Lmk.

The cells in charge of the innate immune response in the marine mussel Mytilus galloprovincialis Lmk. are the haemocytes. These cells respond in different ways to agents such as lipopolysaccharide (LPS), interleukin-2 (IL-2), platelet-derived growth factor (PDGF) and corticotropin releasing factor (CRF). After stimulation of the haemocytes, the expression of molecules reactive with monoclonal antibodies raised to the alpha chain of the IL-2 receptor, present in their membrane, differed depending on the agent used. The same happened with regard to the levels of dopamine, adrenaline and noradrenaline released to the medium by the haemocytes. It should also be noted that no catecholamine release was detected and the level of expression of IL-2Ralpha showed no significant variation in cultured cells that had not been treated with inducers. These facts would indicate that most haemocytes were in the same starting condition at the moment that the stimulation was performed. Therefore, cultured haemocytes can be a highly reliable model in the study of the innate immune system.