RESUMEN
OBJECTIVE: To investigate acute changes in biochemical markers of cartilage turnover in response to moderate intensity exercise with and without joint impact in humans with knee osteoarthritis. DESIGN: We conducted a randomized, cross-over, exploratory clinical study. Twenty subjects with knee osteoarthritis (OA) were randomized, of which twenty completed 30 min of cycling and 15 completed 30 min of running on days 1 week apart. Fasting blood samples were taken before, immediately after and 1, 2, 3, and 24 h after activity was initiated. Midstream spot urine was sampled before and after activity. Serum samples were analyzed for concentrations of fragment of type II collagen degradation, C2M, fragment of type VI collagen degradation, C6M, cartilage oligomeric matrix protein, COMP, marker of type II collagen formation, PRO-C2, and urine for marker of crosslinked type II collagen degradation, CTX-II. To establish a reference, all subjects had similar samples taken during rest on a separate day. Data was analyzed in a restricted maximum likelihood based random effects linear mixed model. RESULTS: C2M trended to increase after cycling compared running (13.49%, 95%CI: -0.36-27.34%) and resting (12.88%, 95%CI: 0.2-25.6%) and the type II collagen formation/degradation ratio switched towards degradation after cycling, but not running. C6M trended to decrease after cycling (-8.1%, 95%CI: -14.8 to -1.4%) and running (-6.8%, 95%CI: -14.16-0.55%). CONCLUSION: In persons with knee OA moderate intensity exercise without joint impact may induce acute changes in circulating levels of biochemical markers reflecting type II and VI collagen degradation.
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Colágeno Tipo II/sangre , Ejercicio Físico , Metaloproteasas/sangre , Osteoartritis de la Rodilla/sangre , Adulto , Anciano , Biomarcadores , Estudios Cruzados , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
PURPOSE: The objective of the present retrospective study was to assess the long-term implant treatment outcome and patient satisfaction after lateral ridge augmentation in the posterior mandible with autogenous bone block graft harvested from the ascending mandibular ramus. MATERIALS AND METHODS: Seventy-four lateral ridge augmentation procedures in the posterior mandible with an autogenous bone block graft harvested from the ascending mandibular ramus and delayed placement of 87 implants was conducted in 46 consecutive patients from 2002-2006. Records and radiographs were retrospectively analyzed. Twenty-four patients responded to a 10-years follow-up examination including 39 lateral ridge augmentation procedures and 48 implants. Survival of suprastructures and implants, peri-implant marginal bone loss, patient perception and professional evaluation of the final implant treatment was assessed after 10 years. RESULTS: The 10-year survival of suprastructures and implants was 100% as all the implants and suprastructures were present with limited peri-implant marginal bone loss. The patients were highly satisfied with the esthetic and implant treatment outcome. CONCLUSION: Lateral ridge augmentation in the posterior mandible with autogenous bone block graft from the ascending mandibular ramus is characterized by high long-term implant survival rate and patient satisfaction.
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Aumento de la Cresta Alveolar , Trasplante Óseo , Implantación Dental Endoósea , Humanos , Mandíbula/cirugía , Estudios RetrospectivosRESUMEN
The objective of the present systematic review was to test the hypothesis that there were no differences in outcome of implant treatment after sandwich osteotomy in the atrophic posterior mandible with interpositional autogenous bone block graft, compared with bone substitute material. A MEDLINE/PubMed, Embase and Cochrane Library search in combination with hand-search of selected journals was conducted. Two short-term randomised controlled trials with a split-mouth study design and low risk of bias fulfilled the inclusion criteria. High survival rate of suprastructures and implants was disclosed with no significant difference between interpositional autogenous bone block graft compared with bone substitute material. Meta-analysis revealed patient-based implant survival risk ratio of 1.05 (95% CI: 0.88 to 1.25) and peri-implant marginal bone loss of 0.31mm (95% CI: -0.29 to 0.90) indicating no significant differences between the two treatments. High implant stability values, gain in vertical alveolar ridge height, bone formation, and few complications were reported with both treatments. Sandwich osteotomy with interpositional grafting material appears to be a predictable surgical technique for enhancement of the vertical alveolar ridge height in the atrophic posterior mandible prior to implant placement.
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Aumento de la Cresta Alveolar , Sustitutos de Huesos , Implantes Dentales , Sustitutos de Huesos/uso terapéutico , Trasplante Óseo , Implantación Dental Endoósea , Humanos , Mandíbula/cirugía , OsteotomíaRESUMEN
The objective was to test the hypothesis of no difference in the treatment outcome after the installation of short implants (≤8mm) in the posterior part of the maxilla compared to standard length implants (>8mm) in conjunction with maxillary sinus floor augmentation (MSFA) using the lateral window technique, after an observation period of ≥3years. A search of the MEDLINE, Embase, and Cochrane Library databases, in combination with a hand-search of relevant journals, was conducted. The search yielded 1102 titles. Finally, three studies that fulfilled the inclusion criteria were included. All were considered to have a low risk of bias. Meta-analyses revealed no significant differences in implant survival or peri-implant marginal bone loss between the two treatment modalities. However, the use of standard length implants in conjunction with MSFA was characterized by a tendency towards more peri-implant marginal bone loss. There was no statistically significant difference between the two treatment modalities with regard to overall patient satisfaction. Short implants seem to be a suitable alternative to standard length implants in conjunction with MSFA. However, further randomized controlled trials with larger patient samples and an observation period of more than 3years are needed before one treatment modality might be considered superior to the other.
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Implantación Dental Endoósea/métodos , Implantes Dentales , Diseño de Prótesis Dental , Seno Maxilar/cirugía , Elevación del Piso del Seno Maxilar , HumanosRESUMEN
BACKGROUND: In patients undergoing open surgery for a ruptured abdominal aortic aneurysm (rAAA), survivors demonstrate a high platelet count, and proactive administration of platelets (and fresh frozen plasma) appears to influence mortality. OBJECTIVES: This trial investigated the effect of platelets administered before transport to surgery. METHODS: In a prospective study design, patients were randomised to receive platelets (intervention; n = 61) or no platelets (control; n = 61) before transport to vascular surgery from 11 local hospitals. The study was terminated when one of the vascular surgical centres implemented endovascular repair for rAAA patients. RESULTS: Thirty days after surgery, mortality was 36% for patients with intervention vs 31% for controls (P = 0·32). Post-operative thrombotic events (14 vs 15; P = 0·69), renal failure (11 vs 10; P = 0·15) and pulmonary insufficiency (34 vs 39; P = 0·15) were similar in the two groups of patients. No adverse reactions to platelet administration were observed. In addition, length of stay in the intensive care unit was unaffected by intervention. CONCLUSIONS: For patients planned for open repair of a rAAA, we observed no significant effect of early administration of platelets with regard to post-operative complications and stay in the ICU or in hospital and also no significant effect on mortality.
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Aneurisma de la Aorta Abdominal , Rotura de la Aorta , Transfusión de Plaquetas , Procedimientos Quirúrgicos Vasculares , Anciano , Aneurisma de la Aorta Abdominal/mortalidad , Aneurisma de la Aorta Abdominal/terapia , Rotura de la Aorta/mortalidad , Rotura de la Aorta/terapia , Femenino , Estudios de Seguimiento , Humanos , Masculino , Complicaciones Posoperatorias , Estudios Prospectivos , Procedimientos Quirúrgicos Vasculares/mortalidadRESUMEN
This study explores the association between postadmission and intraoperative cerebral oxygenation (ScO2), reflecting systemic perfusion, and postoperative mortality and delirium. Forty elderly (age > 65 years) patients with hip fractures were included in this prospective observational study. The ScO2 was determined using near-infrared spectroscopy at initial resuscitation after patients were admitted to the hospital and during surgery. Postoperative delirium was assessed up to seven days after surgery using the memorial delirium assessment scale and the confusion assessment method. Ten patients (25%) developed postoperative delirium within the first seven postoperative days. At initial resuscitation ScO2 was lower in patients that later developed delirium, but the difference was not significant (p = 0.331). Intraoperative ScO2 values remained similar in the two groups. Mortality regardless of cause was 10% (4 out of 40 patients) after 30 days. At initial resuscitation ScO2 was significant lower in the mortality group than in the surviving group (p = 0.042), and the ScO2 nadir values were also significant lower (p = 0.047). Low ScO2 during initial resuscitation (defined as ScO2 < 55 for a minimum of two consecutive minutes) was also significantly associated with 30-day mortality (p = 0.015). There were no associations between low blood pressure and postoperative delirium or 30-day mortality. We found that low preoperative ScO2 was better associated with 30-day all-cause mortality in elderly patients undergoing surgery for hip fracture than blood pressure measurements. Future studies in preoperative resuscitation of hip fracture patients should focus on perfusion measures as opposed to conventional haemodynamic.
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Encéfalo/metabolismo , Fracturas de Cadera/metabolismo , Fracturas de Cadera/cirugía , Oximetría/métodos , Anciano , Anciano de 80 o más Años , Circulación Cerebrovascular , Dinamarca/epidemiología , Delirio del Despertar/etiología , Femenino , Hemodinámica , Fracturas de Cadera/mortalidad , Humanos , Masculino , Monitoreo Intraoperatorio/métodos , Monitoreo Intraoperatorio/estadística & datos numéricos , Oximetría/estadística & datos numéricos , Proyectos Piloto , Periodo Posoperatorio , Periodo Preoperatorio , Estudios Prospectivos , Resucitación , Espectroscopía Infrarroja Corta/métodos , Espectroscopía Infrarroja Corta/estadística & datos numéricosRESUMEN
BACKGROUND: In patients with cardiovascular disease, guidelines for administration of red blood cells (RBC) are mainly based on studies outside the vascular surgical setting with the recommendation to use a haemoglobin (hb) trigger-level lower than by guidelines from The European Society for Vascular Surgery. Restricting RBC transfusion may affect blood O2 transport with a risk for development of tissue ischaemia and postoperative complications. METHODS: In a single-centre, open-label, assessor blinded trial, 58 vascular surgical patients (> 40 years of age) awaiting open surgery of the infrarenal aorta or infrainguinal arterial bypass surgery undergo a web-based randomisation to one of two groups: perioperative RBC transfusion triggered by hb < 8 g/dl or hb < 9.7 g/dl. Administration of fluid follows an individualised strategy by optimising cardiac stroke volume and near-infrared spectroscopy determines tissue oxygenation. Serious adverse event rates are: myocardial injury (troponin-I ≥ 45 ng/l or ischaemic electrocardiographic findings at day 30), acute kidney injury, death, stroke and severe transfusion reactions. A follow-up visit takes place 30 days after surgery and a follow-up of serious adverse events in the Danish National Patient Register within 90 days is pending. DISCUSSION: This trial is expected to determine whether a RBC transfusion triggered by hb < 9.7 g/dl compared with hb < 8 g/dl results in adequate separation of postoperative hb levels, transfusion of more RBC units and maintains a higher tissue oxygenation. The results will inform the design of a multicentre trial for evaluation of important postoperative outcomes.
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Transfusión Sanguínea/métodos , Hemoglobinas/análisis , Procedimientos Quirúrgicos Vasculares/métodos , Anciano , Anestesia , Protocolos Clínicos , Transfusión de Eritrocitos/efectos adversos , Transfusión de Eritrocitos/métodos , Femenino , Fluidoterapia/métodos , Fluidoterapia/normas , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Oxígeno/sangre , Ensayos Clínicos Controlados Aleatorios como Asunto , Proyectos de Investigación , Volumen Sistólico , Resultado del Tratamiento , Procedimientos Quirúrgicos Vasculares/normasRESUMEN
AIM: To evaluate whether muscle vasodilatation plays a role for hypotension developed during central hypovolaemia, muscle oxygenation (Sm O2 ) was examined during (pre)syncope induced by head-up tilt (HUT). Skin blood flow (SkBF) and oxygenation (Sskin O2 ) were determined because evaluation of Sm O2 may be affected by superficial tissue oxygenation. Furthermore, we evaluated cerebral oxygenation (Sc O2 ) and middle cerebral artery mean blood flow velocity (MCAvmean ). METHODS: Twenty healthy male volunteers (median age 24 years; range 19-38) were subjected to passive 50° HUT for 1 h or until (pre)syncope. Sc O2 and Sm O2 (near-infrared spectroscopy), MCAvmean (transcranial Doppler) along with mean arterial pressure (MAP), heart rate (HR), stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) (Modelflow® ) were determined. RESULTS: (Pre)syncopal symptoms appeared in 17 subjects after 11 min (median; range 2-34) accompanied by a decrease in MAP, SV, CO and TPR, while HR remained elevated. During (pre)syncope, Sc O2 decreased [73% (71-76; mean and 95% CI) to 68% (65-71), P < 0.0001] along with MCAvmean [40 (37-43) to 32 (29-35) cm s-1 , P < 0.0001]. In contrast, Sm O2 increased [63 (56-69)% to 71% (65-78), P < 0.0001], while Sskin O2 [64% (58-69) to 53% (47-58), P < 0.0001] and SkBF [71 (44-98) compared to a baseline of 99 (72-125) units, P = 0.020] were reduced. CONCLUSION: We confirm that the decrease in MAP during HUT is associated with a reduction in indices of cerebral perfusion. (Pre)syncope was associated with an increase in Sm O2 despite reduced Sskin O2 and SkBF, supporting that muscle vasodilation plays an important role in the circulatory events leading to hypotension during HUT.
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Hemodinámica/fisiología , Hipovolemia/fisiopatología , Músculo Esquelético/irrigación sanguínea , Síncope/fisiopatología , Adulto , Presión Sanguínea/fisiología , Humanos , Masculino , Oxígeno/sangre , Postura , Resistencia Vascular/fisiología , Vasodilatación/fisiología , Adulto JovenRESUMEN
In healthy humans, stroke volume (SV) and cardiac output (CO) do not increase with expansion of the central blood volume by head-down tilt or administration of fluid. Here, we exposed 85 patients to Trendelenburg's position about one hour after surgery while cardiovascular variables were determined non-invasively by Modelflow. In Trendelenburg's position, SV (83 ± 19 versus 89 ± 20 ml) and CO (6·2 ± 1·8 versus 6·8 ± 1·8 l/min; both P<0·05) increased, while heart rate (75 ± 15 versus 76 ± 14 b min-1 ) and mean arterial pressure were unaffected (84 ± 15 versus 84 ± 16 mmHg). For the 33 patients (39%) with a > 10% increase in SV (from 78 ± 16 to 90 ± 17 ml) corresponding to an increase in CO from 5·9 ± 1·5 to 6·9 ± 1·6 l min-1 (P<0·05) when tilted head-down, administration of 250 ml Ringer's lactate solution increased SV (to 88 ± 18 ml) and CO (to 6·8 ± 1·7 l min-1 ). In conclusion, determination of SV and/or CO in Trendelenburg's position can be used to evaluate whether a patient is in need of IV fluid as here exemplified after surgery.
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Inclinación de Cabeza , Hipovolemia/fisiopatología , Procedimientos Ortopédicos/efectos adversos , Posicionamiento del Paciente , Volumen Sistólico , Adaptación Fisiológica , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Periodo de Recuperación de la Anestesia , Presión Arterial , Femenino , Fluidoterapia , Frecuencia Cardíaca , Humanos , Hipovolemia/diagnóstico , Hipovolemia/etiología , Hipovolemia/terapia , Infusiones Intravenosas , Soluciones Isotónicas/administración & dosificación , Masculino , Persona de Mediana Edad , Selección de Paciente , Cuidados Posoperatorios/métodos , Solución de Ringer , Factores de Tiempo , Adulto JovenRESUMEN
During open abdominal aortic aneurism (AAA) repair cerebral blood flow is challenged. Clamping of the aorta may lead to unintended hyperventilation as metabolism is reduced by perfusion of a smaller part of the body and reperfusion of the aorta releases vasodilatory substances including CO2. We intend to adjust ventilation according end-tidal CO2 tension (EtCO2) and here evaluated to what extent that strategy maintains frontal lobe oxygenation (ScO2) as determined by near infrared spectroscopy. For 44 patients [5 women, aged 70 (48-83) years] ScO2, mean arterial pressure (MAP), EtCO2, and ventilation were obtained retrospectively from the anesthetic charts. By clamping the aorta, ScO2 and EtCO2 were kept stable by reducing ventilation (median, -0.8 l min(-1); interquartile range, -1.1 to -0.4; P < 0.001). During reperfusion of the aorta a reduction in MAP by 8 mmHg (-15 to -1; P < 0.001) did not prevent an increase in ScO2 by 2 % (-1 to 4; P < 0.001) as EtCO2 increased 0.5 kPa (0.1-1.0; P < 0.001) despite an increase in ventilation by 1.8 l min(-1) (0.9-2.7; P < 0.001). Changes in ScO2 related to those in EtCO2 (r = 0.41; P = 0.0001) and cerebral deoxygenation (-15 %) was noted in three patients while cerebral hyperoxygenation (+15 %) manifests in one patient. Thus changes in ScO2 were kept within acceptable limits (±15 %) in 91 % of the patients. For the majority of the patients undergoing AAA repair ScO2 was kept within reasonable limits by reducing ventilation by approximately 1 l min(-1) upon clamping of the aorta and increasing ventilation by approximately 2 l min(-1) when the lower body is reperfused.
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Aneurisma de la Aorta Abdominal/cirugía , Dióxido de Carbono/química , Oxígeno/química , Espectroscopía Infrarroja Corta , Anciano , Anciano de 80 o más Años , Anestésicos , Aorta/fisiología , Presión Arterial , Presión Sanguínea , Encéfalo/metabolismo , Circulación Cerebrovascular/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Consumo de Oxígeno/fisiología , Perfusión , Estudios Retrospectivos , VentilaciónRESUMEN
Free diving is associated with extreme hypoxia. This study evaluated the combined effect of maximal static breath holding and underwater swimming on plasma biomarkers of tissue hypoxemia: erythropoietin, neuron-specific enolase and S100B, C-reactive protein, pro-atrial natriuretic peptide, and troponin T. Venous blood samples were obtained from 17 competing free divers before and 3 h after sessions of static apnea and underwater swimming. The heart was evaluated by echocardiography. Static apnea for 293 ± 78 s (mean ± SD) and subsequent 88 ± 21 m underwater swimming increased plasma erythropoietin from 10.6 ± 3.4 to 12.4 ± 4.1 mIU/L (P = 0.013) and neuron-specific enolase from 14.5 ± 5.3 to 24.6 ± 6.4 ng/mL (P = 0.017); C-reactive protein decreased from 0.84 ± 1.0 to 0.71 ± 0.67 mmol/L (P = 0.013). In contrast, plasma concentrations of S100B (P = 0.394), pro-atrial natriuretic peptide (P = 0.549), and troponin T (P = 0.125) remained unchanged and, as assessed by echocardiography, the heart was not affected. In competitive free divers, bouts of static and dynamic apnea increase plasma erythropoietin and neuron-specific enolase, suggesting that renal and neural tissue, rather than the heart, is affected by the hypoxia developed during apnea and underwater swimming.
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Adaptación Fisiológica/fisiología , Contencion de la Respiración , Buceo , Corazón/fisiología , Hipoxia/sangre , Fosfopiruvato Hidratasa/sangre , Adulto , Atletas , Factor Natriurético Atrial/sangre , Proteína C-Reactiva/metabolismo , Ecocardiografía , Eritropoyetina/sangre , Femenino , Humanos , Masculino , Subunidad beta de la Proteína de Unión al Calcio S100/sangre , Natación , Troponina T/sangreRESUMEN
BACKGROUND: Phenylephrine and ephedrine affect frontal lobe oxygenation ([Formula: see text]) differently when assessed by spatially resolved near infrared spectroscopy. We evaluated the effect of phenylephrine and ephedrine on extra- vs intra-cerebral blood flow and on [Formula: see text]. METHODS: In 10 healthy males (age 20-54 yr), phenylephrine or ephedrine was infused for an â¼20 mm Hg increase in mean arterial pressure. Cerebral oxygenation (SavO2) was calculated from the arterial and jugular bulb oxygen saturations. Blood flow in the internal carotid artery (ICAf) and blood flow in the external carotid artery (ECAf) were assessed by duplex ultrasonography. Invos-5100c (SinvosO2) and Foresight (SforeO2) determined [Formula: see text] while forehead skin oxygenation (SskinO2) was assessed. RESULTS: Phenylephrine reduced SforeO2 by 6.9% (95% confidence interval: 4.8-9.0%; P<0.0001), SinvosO2 by 10.5 (8.2-12.9%; P<0.0001), and ECAf (6-28%; P=0.0001), but increased ICAf (5-21%; P=0.003) albeit with no consequence for SskinO2 or SavO2. In contrast, SforeO2 was maintained with administration of ephedrine while SinvosO2 and SavO2 decreased [by 3.1 (0.7-4.5%; P=0.017) and 2.1 (0.5-3.3%; P=0.012)] as arterial carbon dioxide pressure decreased (P=0.003). ICAf was stable and ECAf increased by 11 (4-18%; P=0.005) with administration of ephedrine while SskinO2 did not change. CONCLUSIONS: The effect of phenylephrine on ScO2 is governed by a decrease in external carotid blood flow since it increases cerebral blood flow as determined by flow in the internal carotid artery. In contrast, ScO2 is largely maintained with administration of ephedrine because blood flow to extracerebral tissue increases.
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Arteria Carótida Externa/efectos de los fármacos , Arteria Carótida Externa/metabolismo , Efedrina/farmacología , Lóbulo Frontal/efectos de los fármacos , Oxígeno/metabolismo , Espectroscopía Infrarroja Corta/métodos , Adrenérgicos/farmacología , Adulto , Lóbulo Frontal/irrigación sanguínea , Lóbulo Frontal/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Adulto JovenRESUMEN
INTRODUCTION: Ultrasound guidance is increasingly used for invasive anaesthetic procedures to improve efficacy, facilitate performance and reduce risk of complications. Herein, we present a simple approach to ultrasound-guided locoregional anaesthesia for patients undergoing eversion carotid endarterectomy. METHODS: At the level of the base of the carotid bifurcation, the needle was inserted at the lateral border of the sternocleidomastoid muscle and, guided by ultrasound, advanced 0.5-1 cm posterolateral to the carotid artery, where ropivacaine (7.5 mg ml(-1)) was injected. During retraction of the needle, additional local anaesthetic was administered beneath the sternocleidomastoid muscle and, finally, subcutaneous infiltration along the surgical incision line was performed. The primary study end point was the amount of additional ropivacaine (7.5 mg ml(-1)) provided intra-operatively. Secondary measures included the occurrence of puncture-related complications and the adverse effects to locoregional anaesthesia. RESULTS: Sixty consecutive patients admitted for primary carotid endarterectomy were prospectively included. The volume of administered ropivacaine for locoregional anaesthesia and subsequent intra-operative supplementation was 31.7 ± 3.5 and 1.9 ± 2.5 ml, respectively. There were no conversions to general anaesthesia. Intravascular or subarachnoid injection of local anaesthetic did not occur, and symptoms of local anaesthetic systemic toxicity did not present. Related to the blockade, hoarseness (72%), Horner syndrome (37%), cough (20%), facial palsy (13%) and dysphagia (12%) were observed and resolved on the first postoperative day. CONCLUSIONS: This observational study demonstrates that the described ultrasound-guided locoregional anaesthesia is suitable for eversion carotid endarterectomy and the amount of supplemental anaesthetic during the surgery is low.
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Anestesia de Conducción/métodos , Anestesia Local/métodos , Anestésicos Locales/administración & dosificación , Arterias Carótidas/diagnóstico por imagen , Estenosis Carotídea/cirugía , Endarterectomía Carotidea , Monitoreo Intraoperatorio/métodos , Anciano , Estenosis Carotídea/diagnóstico por imagen , Plexo Cervical/ultraestructura , Femenino , Humanos , Inyecciones , Masculino , Bloqueo Nervioso/métodos , Estudios Prospectivos , Reproducibilidad de los Resultados , UltrasonografíaRESUMEN
BACKGROUND AND AIMS: We investigated whether in patients with liver cirrhosis reduced muscle strength is related to dysfunction of muscle mitochondria. METHODS: The mitochondrial respiratory capacity of the tibial anterior muscle was evaluated in seven patients and eight healthy control subjects by 31P nuclear magnetic resonance spectroscopy (31PMRS) to express ATP turnover in vivo and by respirometry of permeabilized fibres from the same muscle to express the in vitro capacity for oxygen consumption. RESULTS: Maximal voluntary contraction force for plantar extension was low in the patients (46% of the control value; P < 0.05), but neither the capacity for mitochondrial ATP synthesis, V(max-ATP) (0.38 ± 0.26 vs. 0.50 ± 0.07 mM s(-1) ; P = 0.13) nor the in vitro VO(2max) (0.52 ± 0.21 vs. 0.48 ± 0.21 µmol O2 (min g wet wt.)(-1) P = 0.25) were lowered correspondingly. Also, the activity of citrate synthesis and the respiratory chain complexes II and IV were similar in patients and controls. However during the contractions, the contribution to initial anaerobic ATP production from glycolysis relative to that from PCr was reduced in the patients (0.73 ± 0.22 vs. 0.99 ± 0.09; P < 0.01). CONCLUSIONS: These results demonstrate that the markedly lower capacity for force generation in patients with liver cirrhosis is unrelated to their capacity for muscle ATP turnover, but the attenuated initial acceleration of anaerobic glycolysis suggests that these patients could be affected by a central limitation to force generation.
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Adenosina Trifosfato/metabolismo , Sistema Nervioso Central/fisiopatología , Metabolismo Energético , Cirrosis Hepática/fisiopatología , Mitocondrias Musculares/metabolismo , Contracción Muscular , Fuerza Muscular , Músculo Esquelético/fisiopatología , Adulto , Análisis de Varianza , Estudios de Casos y Controles , Femenino , Glucólisis , Humanos , Análisis de los Mínimos Cuadrados , Modelos Lineales , Cirrosis Hepática/metabolismo , Espectroscopía de Resonancia Magnética , Masculino , Persona de Mediana Edad , Músculo Esquelético/inervación , Músculo Esquelético/metabolismo , Consumo de Oxígeno , Fosfocreatina/análogos & derivados , Fosfocreatina/metabolismoRESUMEN
Exercise lowers the cerebral metabolic ratio of O2 to carbohydrate (glucose+1/2 lactate) and metabolic acidosis appears to promote cerebral lactate uptake. However, the influence of pH on cerebral lactate uptake and, in turn, on the cerebral metabolic ratio during exercise is not known. Sodium bicarbonate (Bicarb, 1 M; 350-500 ml) or an equal volume of normal saline (Sal) was infused intravenously at a constant rate during a '2000 m' maximal ergometer row in six male oarsmen (23±2 years; mean±S.D.). During the Sal trial, pH decreased from 7.41±0.01 at rest to 7.02±0.02 but only to 7.36±0.02 (P <0.05) during the Bicarb trial. Arterial lactate increased to 21.4±0.8 and 32.7±2.3 mM during the Sal and Bicarb trials, respectively (P <0.05). Also, the arterial-jugular venous lactate difference increased from-0.03±0.01 mM at rest to 3.2±0.9 mM (P <0.05) and 3.4±1.4 mM (P <0.05) following the Sal and Bicarb trials, respectively. Accordingly, the cerebral metabolic ratio decreased equally during the Sal and Bicarb trials: from 5.8±0.6 at rest to 1.7±0.1 and 1.8±0.2, respectively. The enlarged blood-buffering capacity after infusion of Bicarb eliminated metabolic acidosis during maximal exercise but that did not affect the cerebral lactate uptake and, therefore, the decrease in the cerebral metabolic ratio.
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Acidosis/metabolismo , Encéfalo/metabolismo , Metabolismo Energético/fisiología , Esfuerzo Físico/fisiología , Adulto , Ergometría , Humanos , Concentración de Iones de Hidrógeno , Ácido Láctico/sangre , Masculino , Músculo Esquelético/metabolismo , Oxígeno/sangreRESUMEN
In the present study we tested four macroalgae species--harvested in Denmark--for their suitability of bioconversion to methane. In batch experiments (53 degrees C) methane yields varied from 132 ml g volatile solids(-1) (VS) for Gracillaria vermiculophylla, 152 mi gVS(-1) for Ulva lactuca, 166 ml g VS(-1) for Chaetomorpha linum and 340 ml g VS(-1) for Saccharina latissima following 34 days of incubation. With an organic content of 21.1% (1.5-2.8 times higher than the other algae) S. latissima seems very suitable for anaerobic digestion. However, the methane yields of U. lactuca, G. vermiculophylla and C. linum could be increased with 68%, 11% and 17%, respectively, by pretreatment with maceration. U. lactuca is often observed during 'green tides' in Europe and has a high cultivation potential at Nordic conditions. Therefore, U. lactuca was selected for further investigation and co-digested with cattle manure in a lab-scale continuously stirred tank reactor. A 48% increase in methane production rate of the reactor was observed when the concentration of U. lactuca in the feedstock was 40% (VS basis). Increasing the concentration to 50% had no further effect on the methane production, which limits the application of this algae at Danish centralized biogas plant.
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Reactores Biológicos , Metano/metabolismo , Algas Marinas/metabolismo , Ulva/química , Ulva/metabolismo , Anaerobiosis , Animales , Biocombustibles , Bovinos , Estiércol , Metano/química , Algas Marinas/química , Factores de TiempoRESUMEN
Several findings suggest a functional and anatomical differentiation along the dorso-ventral axis of the hippocampus. Lesion studies in rats have indicated that the dorsal hippocampus preferentially plays a role in spatial learning and memory, while the ventral hippocampus is involved in anxiety-related behaviors. Based on such findings our aim was to investigate the molecular differentiation along the dorso-ventral axis of the hippocampal granular cell layer of the rat dentate gyrus. Homogeneous isolation of this specific area was performed by laser-capture microdissection and Illumina microarray chips were used to identify genes differentially expressed in dorsal and ventral granular cell layer, respectively. Selected genes were confirmed by quantitative polymerase chain reaction analyses. From the total amount of 22518 probes 229 genes were found to be differentially expressed between dorsal and ventral granular cell layer with a false discovery rate below 5% and with a relative change in gene expression level of 20% or more. From this pool of genes 45 genes were more than two-fold regulated, 13 genes being dorsally enriched and 32 genes being ventrally enriched. Moreover, cluster analysis based on all genes represented on the microarray chip showed a clear differentiation between dorsal and ventral subgroups. Our findings demonstrate a dorso-ventral differentiation in gene expression even at the subregional level of the rat hippocampus, more specifically in the granular cell layer, substantiating the existence of functional heterogeneity along the dorso-ventral axis of the hippocampus.
Asunto(s)
Giro Dentado/metabolismo , Perfilación de la Expresión Génica/métodos , Hipocampo/metabolismo , Microdisección/métodos , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Animales , Expresión Génica , Rayos Láser , Masculino , Ratas , Ratas WistarRESUMEN
BACKGROUND AND AIMS: In a short-term study, Glucagon-like peptide 2 (GLP-2) has been shown to improve intestinal absorption in short bowel syndrome (SBS) patients. This study describes longitudinal changes in relation to GLP-2 treatment for two years. METHODS: GLP-2, 400 micrograms, s.c.,TID, were offered, to eleven SBS patients keeping parenteral support constant. 72-hour nutritional balance studies were performed at baseline, weeks 13, 26, 52 during two years intermitted by an 8-week washout period. In addition, mucosal morphometrics, renal function (by creatinine clearance), body composition and bone mineral density (by DEXA), biochemical markers of bone turnover (by s-CTX and osteocalcin, PTH and vitamin D), and muscle function (NMR, lungfunction, exercise test) were measured. RESULTS: GLP-2 compliance was >93%. Three of eleven patients did not complete the study. In the remaining 8 patients, GLP-2 significantly reduced the fecal wet weight from approximately 3.0 to approximately 2.0 kg/day. This was accompanied by a decline in the oral wet weight intake, maintaining intestinal wet weight absorption and urinary weight constant. Renal function improved. No significant changes were demonstrated in energy intake or absorption, and GLP-2 did not significantly affect mucosal morphology, body composition, bone mineral density or muscle function. CONCLUSIONS: GLP-2 treatment reduces fecal weight by approximately 1000 g/d and enables SBS patients to maintain their intestinal fluid and electrolyte absorption at lower oral intakes. This was accompanied by a 28% improvement in creatinine clearance.
RESUMEN
Endurance training improves muscular and cardiovascular fitness, but the effect on cerebral oxygenation and metabolism remains unknown. We hypothesized that 3 mo of endurance training would reduce cerebral carbohydrate uptake with maintained cerebral oxygenation during submaximal exercise. Healthy overweight males were included in a randomized, controlled study (training: n = 10; control: n = 7). Arterial and internal jugular venous catheterization was used to determine concentration differences for oxygen, glucose, and lactate across the brain and the oxygen-carbohydrate index [molar uptake of oxygen/(glucose + (1/2) lactate); OCI], changes in mitochondrial oxygen tension (DeltaP(Mito)O(2)) and the cerebral metabolic rate of oxygen (CMRO(2)) were calculated. For all subjects, resting OCI was higher at the 3-mo follow-up (6.3 +/- 1.3 compared with 4.7 +/- 0.9 at baseline, mean +/- SD; P < 0.05) and coincided with a lower plasma epinephrine concentration (P < 0.05). Cerebral adaptations to endurance training manifested when exercising at 70% of maximal oxygen uptake (approximately 211 W). Before training, both OCI (3.9 +/- 0.9) and DeltaP(Mito)O(2) (-22 mmHg) decreased (P < 0.05), whereas CMRO(2) increased by 79 +/- 53 micromol x 100 x g(-1) min(-1) (P < 0.05). At the 3-mo follow-up, OCI (4.9 +/- 1.0) and DeltaP(Mito)O(2) (-7 +/- 13 mmHg) did not decrease significantly from rest and when compared with values before training (P < 0.05), CMRO(2) did not increase. This study demonstrates that endurance training attenuates the cerebral metabolic response to submaximal exercise, as reflected in a lower carbohydrate uptake and maintained cerebral oxygenation.
Asunto(s)
Encéfalo/metabolismo , Ejercicio Físico , Sobrepeso/metabolismo , Consumo de Oxígeno , Oxígeno/sangre , Resistencia Física , Adaptación Fisiológica , Adulto , Glucemia/metabolismo , Encéfalo/irrigación sanguínea , Circulación Cerebrovascular , Epinefrina/sangre , Tolerancia al Ejercicio , Hemodinámica , Humanos , Ácido Láctico/sangre , Masculino , Mitocondrias/metabolismo , Norepinefrina/sangre , Sobrepeso/diagnóstico por imagen , Sobrepeso/fisiopatología , Factores de Tiempo , Ultrasonografía Doppler TranscranealRESUMEN
BACKGROUND AND AIMS: Glucagon-like peptide 2 (GLP-2) has been shown to improve intestinal absorption in short bowel syndrome (SBS) patients in a short-term study. This study describes safety, compliance, and changes in quality of life in 11 SBS patients at baseline, week 13, 26, and 52 during two years of subcutaneous GLP-2 treatment, 400 microgram TID, intermitted by an 8-week washout period. METHODS: Safety and compliance was evaluated during the admissions. The Sickness Impact Profile (SIP), Short Form 36 (SF 36), and Inflammatory Bowel Disease Questionnaire (IBDQ) evaluated quality of life. RESULTS: The predominant adverse event was transient abdominal discomfort in 5 of 11 patients, but in 2, both suffering from Crohns disease, it progressed to abdominal pain and led to discontinuation of GLP-2 treatment. One had a fibrostenotic lesion electively resected at the jejuno-ascendo-anastomosis. The investigator excluded a patient due to unreliable feedback. Stoma nipple enlargement was seen in all 9 jejunostomy patients. Reported GLP-2 compliance was excellent (>93%). GLP-2 improved the overall quality of life VAS-score (4.1 +/- 2.8 cm versus 6.0 +/- 2.4 cm, P < .01), the overall SIP score (10.3 +/- 8.9% versus 6.2 +/- 9.5%, P < .001), the mental component of the SF-36 (45 +/- 13% versus 53 +/- 11%, P < .05), and the overall IBDQ score (5.1 +/- 0.9 versus 5.4 +/- 0.9, P < .007) in the 8 patients completing the study. CONCLUSIONS: Long-term treatment with GLP-2 is feasible in SBS patients, although caution must be exercised in patients with a history of abdominal pain. Although conclusions cannot be made in a noncontrolled trial, the high reported compliance might reflect a high treatment satisfaction, where the clinical benefits of GLP-2 may outweigh the discomforts of injections.