Adding dimension to cellular mechanotransduction: Advances in biomedical engineering of multiaxial cell-stretch systems and their application to cardiovascular biomechanics and mechano-signaling.

Hollow organs (e.g. heart) experience pressure-induced mechanical wall stress sensed by molecular mechano-biosensors, including mechanosensitive ion channels, to translate into intracellular signaling. For direct mechanistic studies, stretch devices to apply defined extensions to cells adhered to elastomeric membranes have stimulated mechanotransduction research. However, most engineered systems only exploit unilateral cellular stretch. In addition, it is often taken for granted that stretch applied by hardware translates 1:1 to the cell membrane. However, the latter crucially depends on the tightness of the cell-substrate junction by focal adhesion complexes and is often not calibrated for. In the heart, (increased) hemodynamic volume/pressure load is associated with (increased) multiaxial wall tension, stretching individual cardiomyocytes in multiple directions. To adequately study cellular models of chronic organ distension on a cellular level, biomedical engineering faces challenges to implement multiaxial cell stretch systems that allow observing cell reactions to stretch during live-cell imaging, and to calibrate for hardware-to-cell membrane stretch translation. Here, we review mechanotransduction, cell stretch technologies from uni-to multiaxial designs in cardio-vascular research, and the importance of the stretch substrate-cell membrane junction. We also present new results using our IsoStretcher to demonstrate mechanosensitivity of Piezo1 in HEK293 cells and stretch-induced Ca2+ entry in 3D-hydrogel-embedded cardiomyocytes.

Evaluación del dolor durante la movilización y la aspiración endotraqueal en pacientes críticos / Evaluation of pain during mobilization and endotracheal aspiration in critical patients

OBJETIVOS: 1) Evaluar la prevalencia de dolor durante 2 procedimientos de enfermería, y 2) analizar la utilidad de ciertos signos vitales y del índice biespectral (BIS) para detectar dolor. MÉTODOS: Estudio prospectivo, observacional y analítico de medidas repetidas en pacientes con ventilación mecánica y sedación. Los procedimientos evaluados fueron la aspiración endotraqueal y la movilización con giro. El dolor se evaluó mediante la Behavioral Pain Scale. Valores más o igual se consideraron dolorosos. Se registraron distintos signos fisiológicos y los valores del BIS. Una variación porcentual > 10% se consideró clínicamente relevante. RESULTADOS: Se analizaron 146 procedimientos en 70 pacientes. La prevalencia de dolor durante los procedimientos fue del 94%. Los signos vitales y los valores del BIS aumentaron significativamente durante los procedimientos respecto el reposo, pero solo la variación del BIS alcanzó relevancia clínica. En un subgrupo de pacientes que recibieron analgesia preventiva antes de los procedimientos, el dolor disminuyó significativamente respecto a los pacientes que no recibieron analgesia preventiva (−2 [RIQ: {−5}-0] vs. 3 [RIQ: 1-4]; p<0,001, respectivamente). CONCLUSIONES: Los procedimientos evaluados son dolorosos. La variación de los signos vitales no es un buen indicador de dolor. La variación del BIS podría ser útil, pero precisa nuevas investigaciones. La administración de analgesia preventiva disminuye la prevalencia de dolor durante los procedimientos

OBJECTIVES: 1) To assess the prevalence of pain during nursing care procedures, and 2) to evaluate the usefulness of certain vital signs and the bispectral index (BIS) in detecting pain. METHODS: A prospective, observational analytical study was made of procedures (endotracheal aspiration and mobilization with turning) in critically ill sedated patients on mechanical ventilation. The Behavioral Pain Scale was used to assess pain, with scores of more or equal 3 indicating pain. Various physiological signs and BIS values were recorded, with changes of > 10% being considered clinically relevant. RESULTS: A total of 146 procedures in 70 patients were analyzed. Pain prevalence during the procedures was 94%. Vital signs and BIS values increased significantly during the procedures compared to resting conditions, but only the changes in BIS were considered clinically relevant. In the subgroup of patients receiving preemptive analgesia prior to the procedure, pain decreased significantly compared to the group of patients who received no such analgesia (−2 [IQR: {−5}-0] vs. 3 [IQR: 1-4]; P<.001, respectively). CONCLUSIONS: The procedures evaluated in this study are painful. Changes in vital signs are not good indicators of pain. Changes in BIS may provide useful information about pain, but more research is needed. The administration of preemptive analgesia decreases pain during the procedures

[Evaluation of pain during mobilization and endotracheal aspiration in critical patients]. / Evaluación del dolor durante la movilización y la aspiración endotraqueal en pacientes críticos.

OBJECTIVES: 1) To assess the prevalence of pain during nursing care procedures, and 2) to evaluate the usefulness of certain vital signs and the bispectral index (BIS) in detecting pain. METHODS: A prospective, observational analytical study was made of procedures (endotracheal aspiration and mobilization with turning) in critically ill sedated patients on mechanical ventilation. The Behavioral Pain Scale was used to assess pain, with scores of ≥3 indicating pain. Various physiological signs and BIS values were recorded, with changes of >10% being considered clinically relevant. RESULTS: A total of 146 procedures in 70 patients were analyzed. Pain prevalence during the procedures was 94%. Vital signs and BIS values increased significantly during the procedures compared to resting conditions, but only the changes in BIS were considered clinically relevant. In the subgroup of patients receiving preemptive analgesia prior to the procedure, pain decreased significantly compared to the group of patients who received no such analgesia (-2 [IQR: {-5}-0] vs. 3 [IQR: 1-4]; P<.001, respectively). CONCLUSIONS: The procedures evaluated in this study are painful. Changes in vital signs are not good indicators of pain. Changes in BIS may provide useful information about pain, but more research is needed. The administration of preemptive analgesia decreases pain during the procedures.

Advancing environmental toxicology through chemical dosimetry: external exposures versus tissue residues.

The tissue residue dose concept has been used, although in a limited manner, in environmental toxicology for more than 100 y. This review outlines the history of this approach and the technical background for organic chemicals and metals. Although the toxicity of both can be explained in tissue residue terms, the relationship between external exposure concentration, body and/or tissues dose surrogates, and the effective internal dose at the sites of toxic action tends to be more complex for metals. Various issues and current limitations related to research and regulatory applications are also examined. It is clear that the tissue residue approach (TRA) should be an integral component in future efforts to enhance the generation, understanding, and utility of toxicity testing data, both in the laboratory and in the field. To accomplish these goals, several key areas need to be addressed: 1) development of a risk-based interpretive framework linking toxicology and ecology at multiple levels of biological organization and incorporating organism-based dose metrics; 2) a broadly applicable, generally accepted classification scheme for modes/mechanisms of toxic action with explicit consideration of residue information to improve both single chemical and mixture toxicity data interpretation and regulatory risk assessment; 3) toxicity testing protocols updated to ensure collection of adequate residue information, along with toxicokinetics and toxicodynamics information, based on explicitly defined toxicological models accompanied by toxicological model validation; 4) continued development of residue-effect databases is needed ensure their ongoing utility; and 5) regulatory guidance incorporating residue-based testing and interpretation approaches, essential in various jurisdictions.

Sedación profunda con propofol y alfentanilo en punción folicular vía transvaginal para técnicas de fecundación in vitro / Deep sedation with Propofol and Alfentanyil in transvaginal oocyte retrieval for in vitro fertilization techniques

INTRODUCCIÓN Y OBJETIVO: Se han utilizado múltiples técnicas anestésicas para la punción folicular vía transvaginal guiada por ecografía. Se han asociado diferentes riesgos a este procedimiento y a su tratamiento anestésico. El propósito del estudio es evaluar tiempos de recuperación e incidencia de complicaciones postoperatorias, principalmente náuseas y vómitos, tras el uso de la sedación profunda con Propofol y Alfentanilo. MATERIAL Y MÉTODOS: Cincuenta y seis mujeres, ASA I-II, se sometieron a anestesia i.v. usando Alfentanilo 0,5-1 mg y Propofol 2-2,5 mg para la inducción y Propofol en bolus de 0,5 mg/kg para el mantenimiento. Se registraron episodios de náuseas y vómitos postoperatorios (antes del alta y durante 24h), requerimientos analgésicos, tiempo de recuperación y otras complicaciones. RESULTADOS: Ninguna de las pacientes presentó espisodios eméticos y se registraron náuseas en el 3,57%. El 42,9% de las pacientes no precisó analgesia postoperatoria y solamente 2 pacientes (3,6%) necesitario 3 fármacos para controlar el dolor. El tiempo medio de estancia (ingreso-alta) fue de 1h 59 min. No existieron otras complicaciones postoperatorias. CONCLUSIONES: La sedación profunda con propofol y alfentanilo parece segura para la técnica de punción folicular bajo control por ecógrafo transvaginal, sin complicaciones mayores y con un muy bajo índice de náuseas y vómitos postoperatorios, resultando unas estancias medias adecuadas para el proceso (AU)

INTRODUCTION AND OBJECTIVES: Different types of anaesthetic techniques have been described for ultrasound guided trans-vaginal oocyte retrieval. Different factors are associated with this surgery and its anaesthetic management. The purpose of this study was to evaluate the recovery time and the incidence of postoperative complications, mainly nausea and vomiting, after administration of Propofol and Alfentanyl in these procedures. MATERIAL AND METHODS: Fifty six women, ASA I-II, underwent i.v. anaesthesia using 0,5-1 mg Alfentanyl and 2-2.5 mg/Kg Propofol for induction and 0.5mg/Kg Propofol bolus for maintenance. Postoperative episodes of nausea and vomiting (before discharge and during the first 24h), analgesia requirements, recovery time and other complications were recorded. RESULTS: No episodes of vomiting were recorded and nausea occurred only in two cases (3.57%). 42.9% of the patients did not require an a further analgesia, and only two patients (3.57%) needed three analgesics for pain control. Time from admission until discharge was 1h 59 min. No further complications were registered in the study. DISCUSSION: Deep sedation with propofol and alfentanyl seems to be safe for trans-vaginal oocyte retrieval, without important complications, with a very low index of nausea and vomiting episodes and a short post-operative stay for the procedure (AU)

Cucumber hypocotyls respond to cutin monomers via both an inducible and a constitutive H(2)O(2)-generating system

Hypocotyls from etiolated cucumber (Cucumis sativa L.) seedlings were gently abraded at their surface to allow permeation of elicitors. Segments from freshly abraded hypocotyls were only barely competent for H(2)O(2) elicitation with fungal elicitor or hydroxy fatty acids (classical cutin monomers). However, elicitation competence developed subsequent to abrasion, reaching an optimum after about 4 h. This process was potentiated in seedlings displaying acquired resistance to Colletotrichum lagenarium due to root pretreatment with 2,6-dichloroisonicotinic acid or a benzothiadiazole. Induction of competence depended on protein synthesis and could be effected not only by surface abrasion, but also by fungal spore germination on the epidermal surface or by rotating the seedlings in buffer. Inhibitor studies indicated that the inducible mechanism for H(2)O(2) production involves protein phosphorylation, Ca(2+) influx, and NAD(P)H oxidase. In contrast, a novel cucumber cutin monomer, dodecan-1-ol, also elicited H(2)O(2) in freshly abraded hypocotyls without previous competence induction. This finding suggests the presence of an additional H(2)O(2)-generating system that is constitutive. It is insensitive to inhibitors and has, in addition, a different specificity for alkanols. Thus, dodecan-1-ol might initiate defense before the inducible H(2)O(2)-generating system becomes effective.

Sepsis-related organ failure assessment and withholding or withdrawing life support from critically ill patients.

BACKGROUND: We studied the incidence of withholding or withdrawing therapeutic measures in intensive care unit (ICU) patients, as well as the possible implications of sepsis-related organ failure assessment (SOFA) in the decision-making process and the ethical conflicts emerging from these measures. METHODS: The patients (n = 372) were placed in different groups: those surviving 1 year after ICU admission (S; n = 301), deaths at home (DH; n = 2), deaths in the hospital after ICU discharge (DIH; n = 13) and deaths in the ICU (DI; n = 56). The last group was divided into the following subgroups: two cardiovascular deaths (CVD), 20 brain deaths (BD), 25 deaths after withholding of life support (DWH) and nine deaths after withdrawal of life support (DWD). RESULTS: APACHE III, daily therapeutic intervention scoring system (TISS) and daily SOFA scores were good mortality predictors. The length of ICU stay in DIH (20 days) and in DWH (14 days) was significantly greater than in BD (5 days) or in S (7 days). The number of days with a maximum SOFA score was greater in DWD (5 days) than in S, BD or DWH (2 days). CONCLUSIONS: Daily SOFA is a useful parameter when the decision to withhold or withdraw treatment has to be considered, especially if the established measures do not improve the clinical condition of the patient. Although making decisions based on the use of severity parameters may cause ethical problems, it may reduce the anxiety level. Additionally, it may help when considering the need for extraordinary measures or new investigative protocols for better management of resources.

Competence for Elicitation of H2O2 in Hypocotyls of Cucumber Is Induced by Breaching the Cuticle and Is Enhanced by Salicylic Acid.

To study H2O2 production, the epidermal surfaces of hypocotyl segments from etiolated seedlings of cucumber (Cucumis sativus L.) were gently abraded. Freshly abraded segments were not constitutively competent for rapid H2O2 elicitation. This capacity developed subsequent to abrasion in a time-dependent process that was greatly enhanced in segments exhibiting an acquired resistance to penetration of their epidermal cell walls by Colletotrichum lagenarium, because of root pretreatment of the respective seedlings with 2,6-dichloroisonicotinic acid. When this compound or salicylic acid was applied to abraded segments, it also greatly enhanced the induction of competence for H2O2 elicitation. This process was fully inhibited by 5 [mu]M cycloheximide or 200 [mu]M puromycin, suggesting a requirement for translational protein synthesis. Both a crude elicitor preparation and a partially purified oligoglucan mixture from Phytophthora sojae also induced, in addition to H2O2 production, a refractory state, which explains the transient nature of H2O2 elicitation. Taken together, these results suggest that the cucumber hypocotyl epidermis becomes conditioned for competence to produce H2O2 in response to elicitors by a stimulus resulting from breaching the cuticle and/or cutting segments. This conditioning process is associated with protein synthesis and is greatly enhanced when substances able to induce systemic acquired resistance are present in the tissue.

Multicystic dysplastic kidney: absence of complications in patients treated conservatively.

The optimal treatment, surgical or conservative, for multicystic dysplastic kidney (MDK) is still undetermined. We analyzed prospectively the evolution of 12 children with MDK who were managed conservatively. After a mean follow-up of 32 months, the only complication found was an episode of urinary tract infection in 3 patients. Complete involution of MDK was observed in 9 patients (75%), the mean period for sonographical disappearance being 16 months. Infants with MDK should be closely monitored and nephrectomy performed when MDK compresses neighbor organs or hypertension develops. There is no agreement on the best therapeutic approach in patients in whom MDK involution has not occurred after a prudential waiting time still not determined.

Effect of alpha-ketoglutarate infusions on organ balances of glutamine and glutamate in anaesthetized dogs in the catabolic state.

1. The salt complex of L-(+)-ornithine and alpha-ketoglutarate (2-oxoglutarate) has recently been proposed for the treatment of patients in the catabolic state. As yet, it is unclear which of the two substrates (ornithine or alpha-ketoglutarate) is responsible for the anticatabolic effect. We infused alpha-ketoglutarate into anaesthetized post-operative dogs in order to investigate whether infusion of alpha-ketoglutarate affects the flux of glutamine and glutamate between skeletal muscle and the splanchnic bed. We used three infusion rates: 3, 10 and 20 mumol min-1 kg-1. A steady state of alpha-ketoglutarate concentration in arterial whole-blood was attained only when the infusion rate was 3 mumol min-1 kg-1. 2. Arterial whole-blood concentrations of alpha-ketoglutarate were 8.8 +/- 1.2 mumol/l in the basal period and rose to 208 +/- 41, 344 +/- 61 and 1418 +/- 315 mumol/l after 60 min infusions of alpha-ketoglutarate at 3, 10 and 20 mumol min-1 kg-1, respectively. 3. alpha-Ketoglutarate uptake was measured in skeletal muscle, liver, gut and kidneys in the basal period and during the infusion of alpha-ketoglutarate. The net uptake of infused alpha-ketoglutarate was highest in the skeletal muscle, followed by kidneys, liver and gut. 4. The alpha-ketoglutarate load increased the muscular tissue content of alpha-ketoglutarate from 49.5 +/- 5 to 142 +/- 15 nmol/g of dry substance (P less than 0.001), but did not alter the muscular glutamate or glutamine contents.(ABSTRACT TRUNCATED AT 250 WORDS)

[Experiences from the use of Fibrinkleber in oral and maxillofacial surgery]. / Empeiries apo te chrese sygkolletikes ousias (Fibrinkleber-FK) apo meigma inodogonou, thrombines paragonta XIII kai aprotinines ste gnathocheirourgike.

The combination of highly concentrated fibronogen, thrombin, clotting factor XIII and fibrinolytic inhibitor aprotinin, represents a new biological, haemostatic and adhesive system as "Fibrinkleber". Its way of action is the same as phase II of coagulation mechanism and its result is due to the formation of a strong and extensive fibrin clot. Because of the presence of aprotinin, that inhibits fibrinolysis, this clot remains for a longer period. A fast haemostasis and a maintenance of tissues in contact is attained and the healing becomes easier and accelerated. In addition, Fibrinkleber is completely resorbable and has very good tissue compatibility, contrary to synthetic adhesives. Regarding experimental results the fibrin adhesive system has been applied in 58 clinical cases with the indications: 1. convocation of fistulas introoral or extraoral 2. as biological band 3. extraoral fixation of skin grafts, used in areas with poor possibility of other kinds of skin fixation 4. in cases with clef lip and cleft palace 5. in combination with bioceramic materials 6. in combination with lyo-dura for reconstruction of orbita-floor fractures. We believe that the fibrinkleber cannot help a bad surgical technique nor replace a well made stitch of a wound. It is however possible to: 1. improve the surgical result (normal epithelization of the open intraoral wounds) 2. to shorten the duration of the surgery (dermatic grafts without any stitching) 3. accelerate the healing phases of a surgical wound 4. allow the modification of surgical techniques, when this is possible (convergence of fistulas etc).

Flexibility of erythrocytes in juvenile diabetes mellitus.

The rheological properties of erythrocytes of 47 diabetic children and adolescents were studied. Deformability of red cells of 32 patients under "poor" metabolic control was markedly decreased while the deformability of red cells of patients (15 individuals) under "good" control was normal. This diminished flexibility of erythrocytes of patients under "poor" control can be explained partly by an increased concentration of free fatty acids in plasma. Moreover we found a decreased fluidity of the intracellular hemoglobin caused possibly by a decreased concentration of 2, 3-diphosphoglycerate in the cells.