RESUMEN
Studies demonstrating the successful and safe application of magnetic hyperthermia in large animals are scarce. A therapeutic approach for advanced cancer comprising multicore encapsulated iron oxide (IO) Sarah Nanoparticles (SaNPs), that uniquely self-regulate their temperature, was developed thus overcoming the safety challenges of hyperthermia. SaNPs are intravenously injected and accumulate in tumor tissue, leading to selective heating upon exposure to an external alternating magnetic field (AMF). A series of studies were conducted in healthy swine to assess SaNPs' safety, alone or combined with AMF application. Administration of single high (up to 22 mg IO/kg) or low (3.6 mg IO/kg) SaNP doses had no adverse effects, including no infusion reactions. Vital signs remained stable with no significant clinical pathology changes, and no treatment-associated toxicities. Biodistribution analysis indicated that SaNPs predominantly accumulate in the lungs and clear in a dose- and time-dependent manner. In minipigs that received a single SaNP no-observed-adverse-effect-level (NOAEL)-based dose (3.6 mg IO/kg) with AMF, the average percentage remaining in vital organs after 90 days was 13.7%. No noticeable clinical signs were noted during the 87 to 92-day observation period following irradiation, and no inflammation, necrosis, nor thermal damage were found in the histopathology evaluation. In another minipig, ~ 90 days after three recurrent high doses (14 mg IO/kg), without AMF, almost half of the injected SaNPs were cleared with no residual detrimental effects. We demonstrate that the approach is safe and well tolerated in swine, opening potential avenues as a novel therapeutic modality for cancer patients.
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Hipertermia Inducida , Nanopartículas Magnéticas de Óxido de Hierro , Neoplasias , Animales , Fenómenos Magnéticos , Neoplasias/terapia , Porcinos , Porcinos Enanos , Distribución TisularRESUMEN
We performed autologous uterus transplantation using the living-sheep donor model for team preparation before human uterine transplantation. Five sequential operations (in 3 ewes) were prospectively conducted. Surgical technique included uterus retrieval, graft preparation, and uterus transplantation. Anastomoses were performed at the level of the external iliac. At 3-week follow-up, the uterus and anastomoses were checked for strictures and thrombosis. Two successful auto-transplantations were made, and one failed because of undeveloped uterine arteries (< 1 mm in diameter). In the first two ewes, we identified and used a deep, separate uterine vein, which was not described in other publications. In the third ewe, we used the utero-ovarian vein. The team was able to perform safe dissection and auto-transplantation, with no signs of strictures or thrombosis after 3 weeks. Cold ischemic time was 60 minutes, and warm ischemic time was between 40 and 60 minutes, with no need for re-anastomoses. We noticed that using the deep uterine vein in the sheep model can anatomically simulate better the human uterine vein and the difficulty to approach it. To avoid using unsuitable vessels for anastomoses, the uterine transplantation protocol in humans should include imaging of the donor's uterine vessels.
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Histerectomía , Modelos Animales , Recolección de Tejidos y Órganos/métodos , Útero/irrigación sanguínea , Útero/trasplante , Animales , Isquemia Fría , Femenino , Humanos , Ovinos , Trasplante AutólogoRESUMEN
OBJECTIVE: Cell therapy for myocardial repair is one of the most intensely investigated strategies for treating acute myocardial infarction (MI). The aim of the present study was to determine whether low-level laser therapy (LLLT) application to stem cells in the bone marrow (BM) could affect the infarcted porcine heart and reduce scarring following MI. METHODS: MI was induced in farm pigs by percutaneous balloon inflation in the left coronary artery for 90 min. Laser was applied to the tibia and iliac bones 30 min, and 2 and 7 days post-induction of MI. Pigs were euthanized 90 days post-MI. The extent of scarring was analyzed by histology and MRI, and heart function was analyzed by echocardiography. RESULTS: The number of c-kit+ cells (stem cells) in the circulating blood of the laser-treated (LT) pigs was 2.62- and 2.4-fold higher than in the non-laser-treated (NLT) pigs 24 and 48 h post-MI, respectively. The infarct size [% of scar tissue out of the left ventricle (LV) volume as measured from histology] in the LT pigs was 3.2 ± 0.82%, significantly lower, 68% (p < 0.05), than that (16.6 ± 3.7%) in the NLT pigs. The mean density of small blood vessels in the infarcted area was significantly higher [6.5-fold (p < 0.025)], in the LT pigs than in the NLT ones. Echocardiography (ECHO) analysis for heart function revealed the left ventricular ejection fraction in the LT pigs to be significantly higher than in the NLT ones. CONCLUSIONS: LLLT application to BM in the porcine model for MI caused a significant reduction in scarring, enhanced angiogenesis and functional improvement both in the acute and long term phase post-MI.
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Médula Ósea/efectos de la radiación , Cicatriz/prevención & control , Terapia por Luz de Baja Intensidad/métodos , Infarto del Miocardio/radioterapia , Remodelación Ventricular/efectos de la radiación , Animales , Biopsia con Aguja , Proliferación Celular/efectos de la radiación , Cicatriz/patología , Modelos Animales de Enfermedad , Pruebas de Función Cardíaca , Inmunohistoquímica , Imagen por Resonancia Magnética/métodos , Infarto del Miocardio/patología , Miocardio/patología , Distribución Aleatoria , Valores de Referencia , Porcinos , Resultado del Tratamiento , Remodelación Ventricular/fisiologíaRESUMEN
AIM: Major surgery under general anaesthesia might evoke acute kidney injury (AKI), sometimes culminating in end stage renal disease. We investigated the roles of hyperglycaemia, inflammation and renin-angiotensin system (RAS) activation in induction of AKI following anaesthesia by different anaesthetic drugs and/or regimens. METHODS: Ninety-four Sprague-Dawley rats underwent 1 h-anaesthesia by various protocols, including repeated blood glucose and insulin measurements. Blood samples and kidneys were allocated at sacrifice, for evaluation of renal function, inflammatory status and Angiotensin-II availability. RESULTS: Hyperglycaemia emerged in unconscious rats irrespective of anaesthetic drug choice or anaesthesia regimen. Insulin increase correlated with hyperglycaemia levels. Levels of Cystatin-C, as well as serum and urine neutrophil gelatinase-associated lipocain (NGAL), were significantly augmented. Serum transforming growth factor beta (TGF-ß) and interleukins (IL)-1ß, -4, -6, and -10 were significantly increased. Intra-renal Angiotensin-II, TGF-ß, IL-6 and-10 were significantly increased. IL-1 was decreased. IL-4 remained unaltered. CONCLUSIONS: Acute hyperglycaemia, systemic and intra-renal inflammation and RAS activation were independently triggered by induction of anaesthesia. Each confounder aggravated the impacts of the others, bringing about concomitant deterioration of renal function. Increased insulin secretion attenuated but did not abolish hyperglycaemia. Systemic inflammation was counterforced by anti-inflammatory cytokines, whereas intra-renal inflammation persisted, so that AKI progressed unopposed.
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Lesión Renal Aguda/etiología , Anestesia General/efectos adversos , Glucemia/metabolismo , Hiperglucemia/etiología , Riñón , Sistema Renina-Angiotensina , Lesión Renal Aguda/sangre , Lesión Renal Aguda/inmunología , Lesión Renal Aguda/patología , Lesión Renal Aguda/fisiopatología , Lesión Renal Aguda/orina , Anestesia General/métodos , Animales , Biomarcadores/sangre , Biomarcadores/orina , Citocinas/sangre , Hiperglucemia/sangre , Inmunohistoquímica , Inflamación/sangre , Inflamación/etiología , Inflamación/inmunología , Inflamación/orina , Mediadores de Inflamación/sangre , Mediadores de Inflamación/orina , Insulina/sangre , Riñón/inmunología , Riñón/metabolismo , Riñón/patología , Riñón/fisiopatología , Pruebas de Función Renal , Ratas , Ratas Sprague-Dawley , Factores de Riesgo , Factores de TiempoRESUMEN
BACKGROUND: Ischemia/reperfusion triggers acute kidney injury (AKI), mainly via aggravating hypoxia, oxidative stress, inflammation and renin-angiotensin system (RAS) activation. We investigated the role of angiotensin-converting enzyme (ACE) inhibition on the progression of AKI in a rat model of ischemia/reperfusion. METHODS: Ninety-nine Sprague-Dawley rats were subjected to 1 h ischemia/reperfusion and/or left unilateral nephrectomy, with concurrent intraperitoneal implantation of Alzet pump. Via this pump, they were continuously infused with captopril 0.5 mg/kg/day, captopril 2 mg/kg/day or saline. The rats were sacrificed following 24, 48 or 168 h. Blood samples, 24-h urine collections and kidneys were allocated, to evaluate renal function, angiotensin-II, nitric oxide (NO), apoptosis, hypoxia, oxidative stress and inflammation. RESULTS: Serum creatinine and cystatin-C significantly increased in ischemic rats, coinciding with histopathologic intrarenal damage, decreased NO, augmented angiotensin-II, interleukin (IL)-6, IL-10, transforming growth factor-beta. At the acute reperfusion stage, captopril prevented excessive angiotensin-II synthesis, ameliorated renal dysfunction, inhibited intrarenal inflammation and improved histopathologic findings. Most of the renoprotective effects of captopril were limited predominantly to acute reperfusion stage. Concurrently, captopril significantly decreased NO availability, exacerbated intrarenal hypoxia and augmented oxidative stress. CONCLUSIONS: At the acute stage of renal ischemia/reperfusion-induced AKI, ACE inhibition substantially contributed to the amelioration of acute injury by improving renal function, inhibiting systemic and intrarenal angiotensin-II, attenuating intrarenal inflammation and preserving renal tissue structure. Later on, at the post-reperfusion stage, most of the beneficial effects of captopril administration on the recuperating post-ischemic kidney were no longer evident. Concurrently, ACE inhibition exacerbated intrarenal hypoxia and accelerated oxidative stress, indicating that renal adaptation to some consequences of ischemia does require bioavailability of RAS components.
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Lesión Renal Aguda/tratamiento farmacológico , Lesión Renal Aguda/etiología , Captopril/uso terapéutico , Sistema Renina-Angiotensina/efectos de los fármacos , Daño por Reperfusión/tratamiento farmacológico , Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Animales , Apoptosis/efectos de los fármacos , Determinación de la Presión Sanguínea , Citocinas/metabolismo , Hipoxia/patología , Hipoxia/prevención & control , Inflamación/patología , Inflamación/prevención & control , Pruebas de Función Renal , Masculino , Estrés Oxidativo/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Daño por Reperfusión/complicacionesRESUMEN
AIM: Major surgery under general anaesthesia frequently triggers acute kidney injury by yet unknown mechanisms. We investigated the role of anaesthesia-triggered systemic hyperglycaemia in impairment of renal functioning, renal tissue injury, intra-renal Angiotensin-II synthesis and endogenous insulin production in anaesthetized rats. METHODS: Eighty-eight Sprague-Dawley rats underwent general anaesthesia for 1 h by different anaesthetic compounds. Some of the animals were either injected with high glucose, or received insulin prior to anaesthesia. Blood pressure, renal functioning estimated by cystatin-C and urea, renal perfusion evaluated by laser Doppler technique, blood glucose and insulin were surveyed. Subsequently, rat kidneys were excised, to be used for immunohistochemical examinations or preparation of renal extracts for intra-renal Angiotensin-II measurements. RESULTS: Elevated blood sugar was observed 5 min following induction of anaesthesia, concurrently with deterioration of renal functioning, drop of systemic blood pressure and decreased renal blood flow. Blood insulin concentrations positively correlated with glucose levels. Intra-renal Angiotensin-II was significantly augmented. Immunohistochemical examinations demonstrated enhanced staining for pro-apoptotic proteins and negligible cell proliferation in tubular tissues. Renal damage resultant from anaesthesia-induced hyperglycaemia could be attenuated by insulin injections. Rats challenged with glucose prior to anaesthesia demonstrated cumulative hyperglycaemia, further increase in insulin secretion, drop of renal blood flow and increased apoptosis. The effects were specific, since they could not be mimicked by replacing glucose with mannose. CONCLUSION: Anaesthesia-induced hyperglycaemia affects intra-renal auto-regulation via decreased renal perfusion, thus triggering renal function deterioration and tubular injury. Increased intra-renal Angiotensin-II aggravates the damage. Tight hypoglycaemic control might prevent or, at least, attenuate anaesthesia-induced renal injury.
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Lesión Renal Aguda/etiología , Anestesia General/efectos adversos , Apoptosis , Proliferación Celular , Hiperglucemia/complicaciones , Riñón/irrigación sanguínea , Riñón/patología , Microcirculación , Circulación Renal , Lesión Renal Aguda/sangre , Lesión Renal Aguda/patología , Lesión Renal Aguda/fisiopatología , Angiotensina II/metabolismo , Animales , Biomarcadores/sangre , Glucemia/metabolismo , Presión Sanguínea , Cistatina C/sangre , Modelos Animales de Enfermedad , Glucosa , Hiperglucemia/inducido químicamente , Hiperglucemia/patología , Hiperglucemia/fisiopatología , Insulina/sangre , Riñón/metabolismo , Ratas , Ratas Sprague-Dawley , Factores de Tiempo , Urea/sangreRESUMEN
Acute iron intoxication is associated with depletion of reduced glutathione in hepatocytes and changes in the glutathione system enzymes. We hypothesized that treatment with N-acetylcysteine (NAC), a glutathione reducing agent and an antioxidant, would reduce mortality in acute iron intoxication. We used a rat model to test this hypothesis. Male rats were assigned to 4 groups. Group 1 received 400 mg/kg elemental iron by oral gavage, group 2 received the same dose of iron followed by NAC, group 3 received NAC only, whereas group 4 received distilled water. Iron and liver transaminases in the blood, and glutathione system enzymes in the liver and erythrocytes were measured. Mortality in group 2 was significantly higher after 2, 6, and 24 hours compared with group 1 (P < .001). No deaths were observed in groups 3 and 4. Serum iron levels were significantly higher in group 2 rats compared to group 1 rats (P < .001). Hepatic and erythrocyte glutathione system enzymes were significantly lower among rats in group 2 compared to rats in group 1. The administration of NAC probably increased the absorption of iron through the gastrointestinal tract, causing higher serum iron levels with significant hepatic damage. These results indicate that in a rat model of acute iron intoxication, orally administered NAC may increase mortality.
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Acetilcisteína/administración & dosificación , Antídotos/administración & dosificación , Antioxidantes/administración & dosificación , Hierro/envenenamiento , Enfermedad Aguda , Administración Oral , Animales , Modelos Animales de Enfermedad , Tracto Gastrointestinal/efectos de los fármacos , Glutatión/metabolismo , Hierro/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Ratas , Ratas WistarRESUMEN
BACKGROUND: Hepcidin regulates extracellular iron concentration by inhibiting iron release from macrophages and preventing iron absorption in the intestine. Our objective was to evaluate the expression of hepcidin in the liver in acute iron poisoning in a rat model. METHODS: Male Wistar rats were assigned to group 1, who received 750 mg/kg elemental iron (LD(50)) by gavage, and group 2 (control), who received distilled water. Iron concentrations and liver transaminases were measured in the serum. Hepcidin messenger RNA levels were measured in the liver. RESULTS: Mean serum iron levels, aspartate aminotransferase, alanine aminotransferase, and uric acid were significantly higher in group 1 compared to group 2 (P < .0001, P = .01, P < .0001, and P = 0.0001, respectively). Hepcidin messenger RNA levels in the liver were significantly higher in the study group (P = .005). CONCLUSIONS: In acute iron intoxication, hepcidin expression in the liver significantly increased. Further studies are needed to determine whether hepcidin levels correlate with the severity of the intoxication.
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Péptidos Catiónicos Antimicrobianos/metabolismo , Absorción Intestinal/efectos de los fármacos , Hierro/envenenamiento , Hígado/metabolismo , Enfermedad Aguda , Alanina Transaminasa/sangre , Animales , Aspartato Aminotransferasas/sangre , Modelos Animales de Enfermedad , Hepcidinas , Riñón/metabolismo , Masculino , ARN Mensajero/análisis , Ratas , Ratas Wistar , Ácido Úrico/sangreRESUMEN
Biopotential, the electric potential generated by living tissues, is affected by changes in extracellular electrolyte and glucose concentrations. We aimed to apply correlation between blood glucose concentrations (BGC) and biopotential of peripheral muscles for noninvasive blood glucose measurement. The study included 58 Wistar rats. In part of them, diabetes was induced by streptozotocin injection. Group 1, comprising 19 normal and 5 diabetic rats, received glucose-challenging protocol (intraperitoneal injection of 1 g/ml glucose). Group 2, 24 normal and 6 diabetic rats, received insulin-challenging protocol (three 30 IU insulin injections with 15-min intervals). Four control rats, group 3, were injected with 2-ml saline. BGC were measured by a standard ACCU-CHEK-Sensor Meter and compared with those estimated by biopotential sensor, further designated as GlucoSat, placed around proximal parts of the tails of the anaesthetized animals. GlucoSat results were calculated using the following biopotential equation: BGC(t) = k1 F1(t) + k2 F2(t) k3 F3(t) + k4, based on an experimental model involving estimation of pH, muscle metabolism, and tissue conductance, where t is time, k1-k4 are coefficients, and F1-F4 are functions. Mean biopotential system measured BGC was 181.7 +/- 4.3 mg/dl, not differing statistically from 187.9 +/- 4.3 mg/dl estimated by ACCU-CHEK. Pearson's correlation coefficient (r(2)) was 0.961 (P < 0.00001), indicating strong, direct correlation between the results. Within the nondiabetic group, r(2) was 0.944 (P < 0.00001), while, within the diabetic group, r(2) was 0.974 (P < 0.00001). No significant, adverse skin reactions were concomitantly observed in any experimental group. Biopotential measurements may be used for continuous, noninvasive estimation of changes in BGC. Further studies are needed to evaluate the applicability of this method to humans.
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Fuentes de Energía Bioeléctrica , Automonitorización de la Glucosa Sanguínea/instrumentación , Glucemia/análisis , Diabetes Mellitus Experimental/fisiopatología , Músculo Esquelético/fisiopatología , Animales , Diabetes Mellitus Experimental/sangre , Electromiografía , Glucosa/farmacología , Prueba de Tolerancia a la Glucosa , Masculino , Monitoreo Ambulatorio , Músculo Esquelético/metabolismo , Ratas , Ratas WistarRESUMEN
AIM: Peroxisome proliferator-activated receptor (PPAR)-gamma activation by rosiglitazone decreases manifestation of intrarenal inflammatory hallmarks. Inflammation significantly aggravates renal injury following urinary tract obstruction. The effect of rosiglitazone on renal inflammation following unilateral ureteral obstruction was investigated. METHODS: Ninety-six Sprague-Dawley rats were subjected to unilateral ureteral ligation, or to sham operation. Half of each group received rosiglitazone, 5 mg/kg bodyweight per day. The animals were killed and their kidneys allocated following 1 h, 24 h or 2 weeks, for pathological examination or for intrarenal transforming growth factor (TGF)-beta, interleukin (IL)-4, IL-6, IL-10 and nitric oxide (NO) assessment by specific enzyme-linked immunosorbent assays. Apoptosis rates, extracellular matrix deposition, PPAR-gamma, alpha-smooth muscle actin (alpha-SMA) expression and macrophage infiltration were assessed by specific immunohistological stainings. RESULTS: PPAR-gamma receptor expression was downregulated, and infiltration of macrophages decreased, in all rosiglitazone-treated kidneys. Rosiglitazone significantly decreased apoptosis, TGF-beta, IL-6, alpha-SMA expression and NO availability in obstructed kidneys. Synthesis of IL-10 was unaltered, while IL-4 augmented by Rosiglitazone. Rosiglitazone also affected NO and IL-4 production in sham-operated controls. CONCLUSION: (i) Rosiglitazone attenuates profibrotic and pro-inflammatory responses in a rat model of ureteral obstruction-induced renal inflammation; (ii) rosiglitazone stimulates counteractive anti-inflammatory responses in the damaged kidneys; (iii) in part, rosiglitazone exerts comparable anti-inflammatory effects on obstructed kidneys and unobstructed healthy controls. Taken together, this ascertains the importance of the anti-inflammatory role of rosiglitazone treatment in amelioration of ureteral obstruction-induced renal damage.
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Antiinflamatorios/farmacología , PPAR gamma/agonistas , Tiazolidinedionas/farmacología , Obstrucción Ureteral/complicaciones , Animales , Modelos Animales de Enfermedad , Inmunohistoquímica , Interleucina-10/biosíntesis , Interleucina-4/biosíntesis , Interleucina-6/biosíntesis , Riñón/patología , Masculino , Óxido Nítrico/metabolismo , Ratas , Ratas Sprague-Dawley , Rosiglitazona , Factor de Crecimiento Transformador beta/biosíntesisRESUMEN
BACKGROUND: Vasoconstriction and reactive oxygen species (ROS) accumulation following contrast media (CM) injection are the key factors triggering CM-induced nephropathy. We compared the effects of N-acetylcysteine (NAC), theophylline or sodium bicarbonate on intrarenal vasoconstriction and ROS generation in a rat model of CM-induced nephropathy. METHODS: Following a 3-day dehydration, Sprague-Dawley rats received CM (Telebrix) or sham 'CM' injection of 0.9% saline. Part of them received NAC, theophylline or bicarbonate prior to CM. Medullar renal blood flow was estimated by laser Doppler. The animals were sacrificed 1, 15 or 30 min after the respective treatments, their kidneys allocated and intrarenal STAT-8 isoprostane, PGE(2) and NO assessed. RESULTS: Vasoconstriction was significantly attenuated by NAC. Theophylline only mildly attenuated the perfusion drop at 15 min, and was ineffective following 30 min. Unlike theophylline or bicarbonate, NAC significantly augmented intrarenal PGE(2). NAC, theophylline but not bicarbonate, gradually increased intrarenal NO. In all experimental variables, CM-induced ROS accumulation, represented by STAT-8 isoprostane estimation, progressed undisturbed. CONCLUSIONS: (1) CM-induced intrarenal vasoconstriction was efficiently prohibited by NAC but not bicarbonate or theophylline; (2) the vasodilatory effect of NAC was mediated via increased PGE(2) synthesis, and (3) ROS accumulation was a primary renal response to CM-induced injury, not affected by any pharmacologic manipulations.
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Acetilcisteína/farmacología , Riñón/efectos de los fármacos , Insuficiencia Renal/tratamiento farmacológico , Bicarbonato de Sodio/farmacología , Teofilina/farmacología , Vasoconstricción/efectos de los fármacos , Acetilcisteína/uso terapéutico , Animales , Medios de Contraste/efectos adversos , Dinoprostona/biosíntesis , Depuradores de Radicales Libres/farmacología , Depuradores de Radicales Libres/uso terapéutico , Hipoxia/tratamiento farmacológico , Hipoxia/metabolismo , Ácido Yotalámico/efectos adversos , Ácido Yotalámico/análogos & derivados , Isoprostanos/biosíntesis , Riñón/irrigación sanguínea , Riñón/metabolismo , Microcirculación/efectos de los fármacos , Óxido Nítrico/metabolismo , Ratas , Ratas Sprague-Dawley , Insuficiencia Renal/inducido químicamente , Insuficiencia Renal/metabolismo , Bicarbonato de Sodio/uso terapéutico , Teofilina/uso terapéutico , Vasodilatadores/farmacología , Vasodilatadores/uso terapéuticoRESUMEN
BACKGROUND: Hypoxia resultant from haemorrhagic shock is the primary cause of kidney damage. Application of normobaric hyperoxia therapy (NHT) is an acceptable treatment for acute haemorrhagic shock. We investigated the effect of NHT on amelioration of haemorrhagic shock-induced rat renal failure. METHODS: Twenty-four Sprague-Dawley rats were subjected to gradual blood withdrawal/reperfusion, followed by 12-h, 24-h or 48-h NHT. Verification/monitoring of intrarenal hypoxia was performed using Hypoxyprobe-TM-1. Subsequently, cystatin C, urea and creatinine were assessed in serum by a Hitachi autoanalyser, and NO, 3-nitro-tyrosine, STAT-8-isoprostane and NF-kB in renal medullae and cortices by specific ELISAs. RESULTS: In rats subjected to haemorrhagic shock, 12- to 48-h NHT significantly reduced intrarenal Hypoxyprobe-TM-1 stained areas and attenuated augmentation of urea, creatinine and cystatin C. Haemorrhagic shock resulted in a 10-fold drop of intrarenal NO availability. 12-h and 24-h, but not 48-h, NHT significantly increased cortical/medullar NO synthesis, the latter, however, not approaching the pre-shock values. Significant shock-induced accumulation of STAT-8-isoprostane and 3-nitro-tyrosine was further exacerbated by NHT. Haemorrhagic shock activated NF-kB in ischaemic tissues, which was not attenuated by NHT. CONCLUSIONS: (1) 12- to 48-h NHT decreased intrarenal hypoxia signs and ameliorated deterioration of renal functions in a rat model of haemorrhagic shock-induced renal failure. (2) 12- to 24 h NHT improved bioavailability of NO in cortices/medullae of kidneys recuperating from haemorrhagic shock. (3) If any anti-inflammatory activities were stimulated by NHT, they would not be mediated via the NF-kB pathway. (4) Despite NHT-associated elevation of reactive oxygen species (ROS), early oxygen supply proved mandatory for effective recuperation of ischaemic kidney from detrimental consequences of haemorrhagic shock.
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Lesión Renal Aguda/etiología , Lesión Renal Aguda/terapia , Hiperoxia , Choque Hemorrágico/complicaciones , Lesión Renal Aguda/fisiopatología , Animales , Presión Sanguínea/fisiología , Creatinina/sangre , Cistatina C , Cistatinas/sangre , Dinoprostona/metabolismo , Modelos Animales de Enfermedad , Riñón/metabolismo , Riñón/patología , Masculino , Óxido Nítrico/metabolismo , Estrés Oxidativo/fisiología , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Choque Hemorrágico/fisiopatología , Factor de Transcripción ReIA , Tirosina/análogos & derivados , Tirosina/metabolismo , Urea/sangreRESUMEN
AIM: To determine the feasibility and efficacy of laparoscopic renal cryosurgery using a novel ultrathin ultrashort intracorporeal cryoprobe in a porcine model. MATERIAL AND METHODS: Novel cryoprobes 4 cm in length and 1.5 mm in diameter were manipulated intracorporeally after insertion via a designated 15 mm laparoscopic port. Renal cryoablative lesions were induced laparoscopically in four 40 kg female piglets. We correlated between intraoperative temperature, ice ball geometry, intraoperative ultrasonographic properties, and histology. RESULTS: Laparoscopic manipulation of the cryoprobes was straightforward. No port site bleeding occurred during insertion, freezing, thawing or upon removal of the probes. The 0 degrees C, -20 degrees C, and -40 degrees C isotherms were measured at 6, 8, and 12 mm from the probe circumferentially. Ice-ball volume stabilization as determined by ultrasound occurred after 10 min of activation. Lower temperatures were reached after 10 min of probe activation as compared with 5 min (ice ball diameter 30 mm, DeltaT = 13-21 degrees C). Using a second 10-min-long freeze cycle resulted in a 14-22 degrees C lower temperature within the ice ball compared to a single cycle. Full coagulative necrosis was noted in the areas between the inserted probes with an additional 1-2 mm circumferential rim of severe tubular damage and apoptosis. CONCLUSIONS: Our novel cryoprobe can be used effectively and conveniently in laparoscopic renal cryosurgery. Considering the size of the cryogenic lesion, using a cluster of probes may be advisable.
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Criocirugía/instrumentación , Riñón/cirugía , Laparoscopios , Laparoscopía/métodos , Nefrectomía/métodos , Animales , Modelos Animales de Enfermedad , Diseño de Equipo , Femenino , Riñón/patología , PorcinosRESUMEN
ABSTRACT The proposed mechanism of iron-induced hepatotoxicity is free radical formation. It was hypothesized that the glutathione system of the liver and erythrocytes will be affected by acute iron poisoning. Male Wistar rats, 6-8 weeks of age, were assigned to one of three groups. Group I received distilled water, group II received 400 mg/kg elemental iron, and group III received 750 mg/kg elemental iron. All groups were gavage fed. Iron concentration, glutathione, and glutathione system enzymes were then measured in the liver and erythrocytes. The hepatic level of reduced glutathione (GSH) was significantly lower in groups II (3.1 +/- 4.6 mumol/mg protein) and III (4.7 +/- 4.6 mumol/mg protein) in comparison with group I (11.5 +/- 6.2 mumol/mg protein) (p < 0.001). Hepatic levels of glutathione S-transferase (GST) were higher and glutathione peroxidase (GPX) levels were lower in group III compared to groups II and I (p < 0.001 and p < 0.001). Compared to group I, glutathione reductase (GR) was lower in groups II and III (p < 0.001). There was no correlation between GSH, oxidized glutathione (GSSG), GST, GR, and GPX levels in the erythrocytes and in the liver (p = 0.41, p = 0.48, p = 0.49, p = 0.53, p = 01.4, and p = 0.84, respectively). In conclusion, acute iron intoxication in rats is associated with depletion of reduced glutathione in the liver.
RESUMEN
BACKGROUND: The increasing number of newborns requiring intubation and artificial ventilation in the sophisticated premature and intensive care units of recent years has been followed by a concomitant increase in the number of children who develop tracheal stenosis as a sequela of prolonged intubation, with a consequent increasing need for tracheal surgical repair. This study was designed to evaluate the ability of a new tissue-engineered biodegradable membrane to tightly seal significant tracheal defects. MATERIALS AND METHODS: A surgically induced tracheal defect of 10 x 5 mm was repaired in rabbits using the NVR-7 membrane--a cross-linked copolymer derived from a dextran sulphate gelatin construct. The unique features of this new membrane are biocompatibility, biodegradability, elasticity, and suturability, as well as a smooth sterilization process. The animals were sacrificed and the tracheas examined at 2, 3, 4, and 8 weeks postsurgery. RESULTS: Seven (7) of 8 rabbits undergoing tracheal surgery survived, with a tight air seal and an almost normal airway. Macroscopic and microscopic studies of the removed specimens showed variable degrees of immunogenic reaction toward the membrane. In the long term (2-3 months), a complete regeneration of all the tracheal layers occurred, simulating the original structure and orderly arrangement of a normal trachea. CONCLUSIONS: The surgical correction using the above membrane enabled the operated animals to overcome any respiratory distress, adequately correcting the induced tracheal defect. From this experimental study, we conclude that the new NVR-7 membrane appears to be a promising therapeutic adjunct in the treatment of patients with tracheal defects.
Asunto(s)
Implantes Absorbibles , Materiales Biocompatibles , Membranas Artificiales , Enfermedades de la Tráquea/cirugía , Animales , Materiales Biocompatibles/química , Condrocitos/patología , Sulfato de Dextran/química , Modelos Animales de Enfermedad , Elasticidad , Epitelio/patología , Fibroblastos/patología , Gelatina/química , Polímeros/química , Conejos , Procedimientos de Cirugía Plástica , Regeneración/fisiología , Esterilización , Propiedades de Superficie , Suturas , Tráquea/patología , Tráquea/cirugía , Cicatrización de Heridas/fisiologíaRESUMEN
BACKGROUND: Renal failure is a threatening side-effect of NSAID administration, consequent to NSAID-mediated abrogation of prostaglandin synthesis and resultant renal ischaemia. N-acetylcysteine (NAC) has renoprotective properties. We examined effects of NAC in a rat model of NSAID-induced renal failure. METHODS: Renal failure was generated in 80 rats by 6-day water deprivation and 3-day 15 mg/kg/day diclofenac injection. The rats were concomitantly treated, or not, by NAC, 40 mg/kg/day. Renal function was evaluated by cystatin C, creatinine and urea. Intrarenal blood flow was measured by laser Doppler. The kidneys were subjected to pathological examination or evaluation of intrarenal NO, H2O2 and PGE2. RESULTS: NAC significantly attenuated deterioration of renal function in diclofenac-treated rats: cystatin C dropped from 2.8+/-0.35 to 2.2+/-0.67 mg/l, P=0.016; creatinine from 1.2+/-0.97 to 0.96+/-0.19 mg/dl, P=0.02; urea from 208.4+/-57.9 to 157.6+/-33.7 mg/dl, P=0.028. Diclofenac-inflicted hystopathological damage was significantly reduced following NAC treatment. Intrarenal medullar blood flow dropped by 51+/-12.4% in diclofenac-treated rats, but only by 14+/-3.39% in those receiving NAC after diclofenac injection (P<0.001). H2O2 was elevated in renal tissues of diclofenac-receiving rats, while decreased in NAC-treated animals. PGE2 release by diclofenac-treated rats dropped significantly, but was restored after NAC administration both in renal cortices (144.7+/-10.4 vs 19.7+/-1.5 pmol/ml, P<0.001) and medullae (148.5+/-7.3 vs 66.6+/-7.3 pmol/ml, P<0.001). CONCLUSIONS: In this model of renal failure induced by NSAID administration combined with water deprivation, NAC treatment successfully attenuated the deterioration of renal function by inducing renal vasodilatation, decreasing oxidative stress via inhibition of intrarenal ROS content and restoration of intrarenal PGE2 release back to the basal levels.
Asunto(s)
Acetilcisteína/farmacología , Antiinflamatorios no Esteroideos , Citoprotección , Dinoprostona/biosíntesis , Riñón/efectos de los fármacos , Riñón/metabolismo , Insuficiencia Renal/inducido químicamente , Insuficiencia Renal/fisiopatología , Animales , Diclofenaco , Peróxido de Hidrógeno/antagonistas & inhibidores , Riñón/fisiopatología , Corteza Renal/metabolismo , Médula Renal/irrigación sanguínea , Médula Renal/metabolismo , Masculino , Microcirculación/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Circulación Renal/efectos de los fármacos , Insuficiencia Renal/metabolismo , Distribución TisularRESUMEN
UNLABELLED: Inappropriate cuff filling is responsible for various complications related to the use of an endotracheal tube (ETT). In this study, we evaluated an objective, noninvasive method for continuous assessment of leak around the ETT cuff by monitoring carbon dioxide pressure (P(CO2) in the upper airway. P(CO2) levels were measured by capnography simultaneously between the ETT cuff and the vocal cords, at the oropharynx, and in the nares of the nose. Cuff filling was regulated by an electronic controller to achieve the minimal pressure needed to prevent CO2 leak. Feasibility of the method was assessed in a human simulator and in a porcine model. Clinical function was evaluated in 60 patients undergoing surgery, comparing the method to the standard anesthesiologist evaluation. Linear correlations were observed between the ETT cuff pressure and P(CO2) level in the human simulator (R2 = 0.954, P < 0.0001) and in the porcine model (R2 > 0.98, P < 0.0001). Iodine leak around the ETT cuff, in the porcine model, occurred only when P(CO2) levels were >2 mm Hg. In the surgery patients, the mean ETT cuff pressure determined clinically by the anesthesiologist was significantly higher than the optimal cuff pressure assessed by P(CO2) (25.2 +/- 3.6 versus 18.2 +/- 7.8 mm Hg, respectively; P < 0.001). According to these findings, optimal ETT cuff filling pressure can be identified by monitoring P(CO2) at the nares or the oropharynx. IMPLICATIONS: A new, objective, noninvasive method for optimizing endotracheal tube cuff filling based on monitoring carbon dioxide levels in the upper airways can be used to identify the minimal cuff pressure necessary to eliminate leak and prevent aspiration.
Asunto(s)
Dióxido de Carbono/análisis , Intubación Intratraqueal/métodos , Animales , Humanos , Masculino , Simulación de Paciente , Presión , PorcinosRESUMEN
Congenital hypertrophic pyloric stenosis (CHPS) is a common condition in infancy associated with smooth muscle hypertrophy and resulting in pyloric outlet obstruction. The final diagnosis of CHPS is based on precise ultrasonographic measurements of length and width of the pyloric muscle. Based on our clinical and sonographic experience, we observed that smaller measurements of the pyloric muscle were obtained in dehydrated infants than in children examined after proper fluid restoration. The clinical importance of these observations was evident because false-negative results could be obtained. An experimental animal work followed, proving our clinical observation to be true. A significant difference of about 30% to 50% was found between measurements of the muscle thickness of the gastric and pyloric muscles in a state of water deprivation, as compared with a state of full hydration (p < 0.05). Based on our preliminary results, we suggest that children with suspected CHPS should be well hydrated before the ultrasound (US) examination is performed, to avoid false-negative results and a consequent delay in treatment.