ABSTRACT
Resumen Introducción: Los aloinjerto cutáneos (AC) son excelentes sustitutos cutáneos temporales, sin embargo, la donación y procura de piel cadavérica, fuente habitual de AC, es baja. Objetivo: Evaluar la factibilidad de utilizar la piel proveniente de abdominoplastías como fuente de AC y su eficacia clínica. Materiales y Método: Entre el 17 de agosto de 2020 al 28 de febrero de 2021 se analizó una cohorte prospectiva de 14 pacientes femeninas sometidas a abdominoplastía por motivos estéticos, que aceptaron donar la piel del colgajo cutáneo abdominal redundante, la cual fue criopreservada. Se utilizaron los AC de piel total criopreservados (ACPTC) en 10 pacientes con diagnósticos de: pie diabético (4), laparostomía contenida (2) herida compleja extremidad inferior (2), sarcoma de cuero cabelludo recidivado (1) y melanoma (1). Resultados: Se obtuvieron 14 colgajos de piel total, los cuales fueron procesados obteniendo una superficie promedio de 302 cm2 y 8,3 láminas de distintos tamaños de utilidad clínica por paciente. En todos los pacientes en que se utilizó ACPTC hubo un prendimiento inicial del AC para posteriormente, en promedio 21 días, presentar una escara necrótica que al ser retirada presentaba un tejido vital adherido al receptor rico en fibroblastos, siendo algunos pacientes auto injertados y otros manejados con cicatrización por segunda intención como tratamiento definitivo. Discusión: Los ACPTC proporcionan una cobertura intermedia, pues una parte se integra en forma definitiva, actuando como un andamiaje biológico para la formación de una interfase sobre la cual se puede autoinjertar o dejar evolucionar con cicatrización por segunda intención y una parte es rechazada. Conclusión: La procura de piel de donante vivo, en pacientes sometidos a cirugías de contorno corporal es un proceso factible, fuente de ACPTC, los cuales permiten una nueva cobertura intermedia con múltiples aplicaciones clínicas.
Introduction: Skin allografts (SA) are outstanding temporary skin substitutes; however, cadaveric skin donation and procurement, a common source of SA, remains low. Aim: To evaluate the feasibility and clinical efficacy of using skin from abdominoplasties as a source of SA. Materials and Method: A prospective cohort was analyzed from August 17th, 2020 and February 28th, 2021, with 14 female patients submitted to abdominoplasty surgeries for aesthetic motives, who authorized skin donation from the redundant abdominal flap which was posteriorly cryopreserved. Cryopreserved total skin allografts (CTSA) was used in 10 patients with the following diagnoses: diabetic foot (4), contained laparostomy (2) complex wound of the lower limb (2), relapsing sarcoma of the scalp (1), and melanoma (1). Results: 14 CTSA were obtained, which were processed, obtaining an average area of 302 cm2 and 8.3 sheets of different sizes and clinical applications from each patient. In all patients who received CTSA, an initial attachment was observed, followed by the appearance of a necrotic scar in an average of21 days. The peeling of the latter revealed a vital tissue tightly adhered to the receptor and rich in fibroblasts. Some of the patients received autografts, and others were managed with secondary intention scarring as a definite treatment. Discussion: CTSA provide an intermediate coverage since one part is definitely adhered to, acting as a biologic scaffolding for the formation of an interface that can be autografted or left for a secondary intention scarring, and the host rejects the other portion. Conclusión: skin procurement from a living donor in patients submitted to body contour surgeries is a feasible process and significant source of CTSA, which permits a new intermediate coverage with multiple clinical uses.
Subject(s)
Humans , Female , Cryopreservation , Abdominoplasty/methods , Allografts/surgery , Skin , Medical Examination , Surveys and Questionnaires , Informed ConsentABSTRACT
El bazo se localiza en el cuadrante superior izquierdo del abdomen, relacionándose posteriormente con la 9a a 11a costilla, de las que se separa por el diafragma y el receso costodiafragmático, se localiza por detrás del estómago y lateralmente al riñón izquierdo. Por alteraciones en su desarrollo pueden generarse bazos accesorios (BA), considerándose un tejido ectópico del bazo. Se consideran tejido normal, con los mismos procesos fisiológicos que el bazo principal. Con el propósito de localizar y determinar aspectos biométricos de los mismos, se realizó un estudio de corte transversal y de carácter descriptivo, sobre una muestra de 220 exámenes de TC pertenecientes a pacientes mayores de 18 años del Hospital Regional Hernán Henríquez Aravena, Temuco, Chile. Para este estudio se excluyeron toda aquellas TC con antecedentes de esplenectomía y lesiones de Bazo o peri-esplénicas. El análisis de los datos mostró una prevalencia de 32,3 % de BA, pudiendo ser de una única presencia, dos e incluso tres BA por paciente.De un total de 71 personas que tienen al menos un BA, 34 (47,89 %) fueron de sexo femenino y 37 (52,11 %) de sexo masculino. Hubo 56 pacientes (78,9 %) con un BA, 29 (40,85 %) del sexo femenino y 27 (38,03 %) del masculino; 15 (21,1 %) presentaron más de un BA, 5 (7,04 %) de sexo femenino y 10 (14,08 %) de sexo masculino, si bien se puede observar variación en la cantidad de BA según sexo, no existe una relación estadísticamente significativa entre dichas variables. La ubicación más frecuente encontrada en el plano axial fue la zona antero-medial con 59 casos (66,29 %); asimismo, en el plano sagital, la localización más frecuente fue en el polo inferior con 40 casos (44,44 %). Datos biométricos de estos BA son mostrados en Tablas. Esta información será de gran valor morfológico y médico debido a la escasa literatura existente sobre esta materia en individuos chilenos.
The spleen is located in the upper left quadrant of the abdomen, subsequently related to the 9th to 11th rib, from which it is separated by the diaphragm and the cost-diaphragmatic recess, it is located behind the stomach and laterally to the left kidney. Due to alterations in its development, accessory spleens (AS) can be generated, being considered an ectopic tissue of the spleen. The AS are considered normal tissue, with the same physiological processes as the main spleen. With the purpose of locating and determining biometric aspects of them, a cross-sectional and descriptive study was carried out on a sample of 220 CT scans belonging to patients over 18 years of age at the Hernán Henríquez Aravena Regional Hospital, Temuco, Chile. For this study, all CT scans with a history of splenectomy and spleen or peri-splenic lesions were excluded. The analysis of the data showed a prevalence of 32.3 % of AS, being able to be of a single presence, two and even three AS per patient. Of a total of 71 people who have at least one AS, 34 (47.89 %) were female and 37 (52.11 %) male. There were 56 patients (78.9 %) with a one AS, 29 (40.85 %) of the female sex and 27 (38.03 %) of the male; 15 (21.1 %) presented more than one AS, 5 (7.04 %) female and 10 (14.08 %) male, although variation in the amount of AS according to sex can be observed, no there is a statistically significant relationship between these variables. The most frequent location found in the axial plane was the anteromedial zone with 59 cases (66.29 %); also, in the sagittal plane, the most frequent location was in the lower pole with 40 cases (44.44 %). Biometric data of these AS are shown in tables. This information will be of great morphological and medical value due to the limited existing literature on this subject in Chilean individuals.
Subject(s)
Humans , Male , Female , Adult , Spleen/abnormalities , Spleen/diagnostic imaging , Tomography, X-Ray Computed , Spleen/anatomy & histology , Chile , Sex Factors , Prevalence , Cross-Sectional StudiesABSTRACT
Praziquantel is a broad spectrum antihelmintic agent and represents the drug of choice for the treatment of schistosomiasis. However, its low aqueous solubility and strong bitter taste highly affect the bioavailability and compliance in pediatric patients. Thus, the purpose of this study was to develop a dry nanosuspension, by a combination of high-pressure homogenization and spray drying, intended for redispersion in a pleasant taste vehicle for extemporaneous use. Three formulations, varying stabilizers to drug ratio, were developed and characterized in terms of particle size distribution, crystallinity, morphology, in vitro dissolution, and sedimentation-redispersibility behavior. A significant reduction in particle size was achieved after the high-pressure homogenization process, and the nanoparticles were further microencapsulated by spray drying technique. The redispersed dried powders exhibited a conserved particle size distribution (in the nanometric range) and certain crystallinity extent, with satisfactory redispersion ability. Besides, the enhancement of the dissolution performance obtained after comminution was conserved, even after drying and redispersion of the extemporaneous powdered formulation. In conclusion, the developed nanoparticle-loaded powders comprise an interesting tool for the administration of praziquantel to preschool-age children.
Subject(s)
Anthelmintics/administration & dosage , Nanoparticles/administration & dosage , Praziquantel/administration & dosage , Schistosomiasis/drug therapy , Child , Drug Compounding/methods , Humans , Particle Size , Powders , Praziquantel/chemistryABSTRACT
The WHO Strategy and Plan of Action on eHealth 2012-2017 highlights knowledge management and digital literacy as key elements for quality of care, health promotion and disease prevention, insofar as they guarantee training and better access to information in an equitable manner. This work proposes a digital literacy program for the development of skills in social media use for information management, communication and eLearning, aimed at Cuban health professionals.
Subject(s)
Health Literacy , Social Media , Communication , Health Personnel , Humans , Literacy , TelemedicineABSTRACT
Resumen La polineuropatía desmielinizante inflamatoria crónica (CIDP por sus siglas en inglés) corresponde a un espectro de diferentes fenotipos clínicos caracterizados por lesiones de naturaleza autoinmune, inflamatoria y desmielinizante, que afectan primariamente nervios periféricos y raíces nerviosas. Generalmente, los pacientes con CIDP presentan un curso crónico de discapacidad neurológica, pero hasta un tercio de los casos puede exhibir un curso remitente-recidivante. El fenotipo clásico involucra compromiso simétrico de la fuerza muscular y la sensibilidad proximal y distal, asociado a arreflexia generalizada. El diagnóstico requiere la demostración de la desmielinización de nervios mediante electromiografía o biopsia de nervios. Debido a la afectación de personas relativamente jóvenes, laboralmente activos, y a la gran discapacidad neurológica que puede generar, el tratamiento debiera ser iniciado precozmente. Los pilares de la terapia en su fase inicial son los corticoides intravenosos en altas dosis, inmunoglobulina intravenosa y la plasmaféresis, mientras que la terapia de mantención se basa, principalmente, en el uso de corticoides orales a bajas dosis. Este artículo presenta el caso de un paciente evaluado en nuestro hospital y diagnosticado con CIDP, y expone una revisión bibliográfica actualizada de la enfermedad.
Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) can be defined as a spectrum of different clinical phenotypes which are characterized by autoimmune, inflammatory and demyelinating injuries, primarily affecting the peripheral nerves and nerve roots. Most patients with CIDP have a chronic course of neurological disability, but about a third of cases exhibit a relapsing-remitting course. Classic phenotype of CIDP involves symmetric compromise of proximal and distal muscle strength and sensitivity, associated with generalized areflexia. For an accurate diagnosis, demonstration of nerve demyelination by electromyography or nerve biopsy is required. Due to the affectation of relatively young, labor-active people and the high risk for neurological disability by the disease, treatment should be initiated early. The predominant lines of therapy, in its initial phase, are high-dose intravenous corticosteroids, intravenous immunoglobulin and plasmapheresis, while the maintenance therapy is mainly based on low-dose oral corticosteroids. This article presents a case report of a patient evaluated in our hospital and diagnosed with CIDP and exposes an updated literature review about this disease.
Subject(s)
Humans , Male , Middle Aged , Peripheral Nerves , Polyneuropathies , Autoimmune Diseases , Demyelinating DiseasesABSTRACT
Expressed emotion, burden and quality of life of relatives received attention because of the increasing interest in predicting and preventing relapse in psychotic patients; but they have subsequently acquired interest of their own as important aspects of families' psychological well-being. The study explores whether the psychological distress and illness perception of a sample of relatives of Mexican patients with psychosis can predict their levels of expressed emotion, burden and quality of life above patients' clinical and functional status. Sixty-five patient-relative dyads were interviewed. Relatives self-reported on expressed emotion, burden, quality of life, psychological distress and illness perception. Patients' clinical and functional status was rated by an interviewer. Pearson correlations and hierarchical multiple linear regressions were used for statistical analyses. Patients' functional status and relatives' psychological distress were significantly associated with expressed emotion, burden and quality of life. Patients' clinical status and relatives' illness perception were most strongly related to expressed emotion and burden. Relatives' psychological distress and illness perception dimensions predicted both burden and quality of life, over and above patients' clinical and functional status. Results underscore the relatives' need of support to overcome their own distress and concerns about the illness, for the psychological well-being of both patients and relatives.
Subject(s)
Cost of Illness , Expressed Emotion/physiology , Family/psychology , Psychotic Disorders/nursing , Quality of Life/psychology , Schizophrenia/nursing , Adult , Caregivers/psychology , Female , Humans , Male , Mexico , Middle AgedSubject(s)
Animals , Fishes/physiology , Fishes/classification , Vocalization, Animal , Acoustics , UruguayABSTRACT
Objetivo. El objetivo de este trabajo fue comparar los índices espontáneos e inducidos en ratones de ambos sexos de las líneas Balb/c, NMRI, OF-1 y C57BL/6/cenp, mediante el ensayo de aberraciones cromosómicas en células de la médula ósea. Materiales y métodos. Con este fin se determinó la línea más eficiente, sobre la base de la aparición significativa de índices espontáneos más bajos e índices inducidos altos a sustancias mutagénicas como la ciclofosfamida (CF). Resultados. Se obtuvo como resultado que la línea Balb/c en ambos sexos difiere significativamente de las demás líneas evaluadas. En esta línea se encontró el menor número de células totales con aberraciones estructurales y un mayor número de inducción de aberraciones cromosómicas cuando es utilizada la CF como mutágeno. Conclusiones. Este trabajo permitirá utilizar la mejor línea de ratones como biomodelo en este ensayo de genotoxicidad, además que le confiere a esta técnica citogenética mayor veracidad y robustez.
Objective. The aim of this study was to compare spontaneous and induced rates in mice of both sexes of lines BALB / c, NMRI, OF-1 and C57BL/6/ cenp, by testing chromosomal aberrations in bone marrow cells. Materials and methods. For this purpose, the most efficient line was determined, based on the significant appearance of lower spontaneous rates and higher induced rates to mutagen substances such as cyclophosphamide (CP). Results. The result obtained was that line Balb / c, in both sexes, differs significantly from the other lines tested. The lesser total number of cells with structural aberrations was found in this line and a greater number of induction of chromosomal aberrations when CP was used as a mutagen. Conclusions. This work will give way to the use of the best line of mice as bio model in this genotoxicity test, and will also give this cytogenetic technique greater veracity and robustness.
Subject(s)
Bone Marrow , Chromosome Aberrations , MiceABSTRACT
We studied some biochemical, toxic and immunological characteristics of the venoms of Bothrops atrox, Bothrops brazili and Lachesis muta, Viperidae responsible for most of the bites of venomous snakes in French Guiana. Chromatographic (HPLC) and electrophoretical profiles (SDS-PAGE), lethal, hemorrhagic, defibrinogenating, coagulant, thrombin like, proteolytic, fibrino(geno)lytic and phospholipase activities were studied. In addition, the neutralization of some toxic activities conferred by four antivenins was compared. The chromatographic and electrophoretic profiles were different for the three venoms, showing differences between Bothrops and L. muta venoms. In general, bothropic venoms showed the highest toxic and enzymatic activities, while the venom of L. muta showed the lowest lethal, hemorrhagic and coagulant activities. The enzymes of bothropic venoms responsible for gelatinolytic activity were around 50-90 kDa. All the venoms were able to hydrolyze a and beta chains of the fibrinogen, showing different patterns of degradation. Although all the antivenoms tested were effective to various degrees in neutralizing the venom of B. brazili and B. atrox, neutralization of L. muta venom was significantly better achieved using the antivenom including this venom in its immunogenic mixture. For the neutralization of L. muta venom, homologous or polyvalent antivenoms that include the "bushmaster" venom in their immunogenic mixture should be preferred.
Subject(s)
Antivenins/therapeutic use , Snake Venoms/classification , Snake Venoms/toxicity , Animals , Bites and Stings/drug therapy , Bites and Stings/epidemiology , Crotalid Venoms/toxicity , French Guiana/epidemiology , Humans , Neutralization Tests , Viper Venoms/toxicityABSTRACT
Atrial natriuretic peptide (ANP) and endothelin (ET) are endogenous vasoactive factors that exert potent diuretic and natriuretic actions. We have previously shown that ANP and ET-3 act through an NO pathway to inhibit the sodium-glucose cotransporter (SGLT) in the intestine [Gonzalez Bosc LV, Elustondo PA, Ortiz MC, Vidal NA. Effect of atrial natriuretic peptide on sodium-glucose cotransport in the rat small intestine. Peptides 1997; 18: 1491-5; Gonzalez Bosc LV, Majowicz MP, Ortiz MC, Vidal NA. Effects of endothelin-3 on intestinal ion transport. Peptides 2001; 22: 2069-75.]. Here we address the role of ANP and ET-3 on SGLT activity in renal proximal tubules. In rat renal cortical brush border membranes (BBV), fluorescein isothiocianate (FITC) labeling revealed a specific 72-kD peptide that exhibits increased FITC labeling in the presence of Na+ and D-glucose. Using alpha-14C-methylglucose active uptake, rat BBV were shown to possess SGLT activity with an affinity constant (K(0.5) approximately 2.4 mM) that is consistent with the expression of the low-affinity, high-capacity SGLT2 isoform. SGLT2 activity in these preparations is dramatically inhibited by ANP and ET-3. This inhibition is independent of changes in membrane lipids and is mimicked by the cGMP analogue, 8-Br-cGMP, suggesting the involvement of cGMP/PKG pathways. These results are the first demonstration that both ANP and ET-3 inhibit rat cortical renal SGLT2 activity, and suggest a novel mechanism by which these vasoactive substances modulate hydro-saline balance at the proximal tubular nephron level.
Subject(s)
Atrial Natriuretic Factor/pharmacology , Endothelin-3/pharmacology , Kidney Tubules, Proximal/metabolism , Monosaccharide Transport Proteins/antagonists & inhibitors , Animals , Biological Transport/drug effects , Cell Membrane/drug effects , Cyclic GMP/metabolism , Kidney Tubules, Proximal/drug effects , Male , Microvilli/chemistry , Microvilli/drug effects , Microvilli/metabolism , Molecular Weight , Monosaccharide Transport Proteins/metabolism , Nitric Oxide/metabolism , Rats , Rats, Wistar , Sodium-Glucose Transporter 2ABSTRACT
We investigated the effects of endothelin 3 (ET-3) on electrolyte transport in rat small intestine using a voltage clamp technique in Ussing's chamber. ET-3 diminished potential difference (PD) and short circuit current (Isc). ET-3 did not affect PD or Isc in low Na(+) and/or D-glucose-free medium. Phloridzine (an inhibitor of sodium-glucose cotransporter [SGLT1]) pretreatment abolished the effect of ET-3 on Isc. Methylene blue (a soluble guanylate cyclase inhibitor) or N-nitro-L-arginine methyl ester (a NOS inhibitor) pretreatment delayed the effect of ET-3 on PD and Isc. ET-3 enhanced NOS activity on enterocytes and systemic NO production. Then, ET-3 could inhibit SGLT1 with the participation of NO.
Subject(s)
Endothelin-3/pharmacology , Intestine, Small/drug effects , Animals , Intestine, Small/enzymology , Intestine, Small/metabolism , Ion Transport , Male , NADPH Dehydrogenase/metabolism , Nitrates/urine , Nitric Oxide/physiology , Nitrites/urine , Rats , Rats, WistarABSTRACT
The intestinal tract is a target organ for atrial natriuretic peptide (ANP), characterized by various biologic activities, immunoreactivity, as well as specific binding sites for ANP. A review of previous studies reveals that ANP is an important regulator of water and nutrient intake, which acts via multiple signaling pathways including activation of guanylyl cyclase to produce its biologic responses. As a regulator, the peptide locally controls hydrosaline balance and acute systemic effects. Therefore, ANP could also act as a local mediator or paracrine effector of intestinal function.
Subject(s)
Atrial Natriuretic Factor/pharmacology , Digestive System/drug effects , Intestines/drug effects , Biological Transport/drug effects , Enterocytes/drug effects , Gastrointestinal Motility/drug effects , Models, Biological , Signal TransductionABSTRACT
The aim of the present study was to determine the relationship between the hypotensive effect of the atrial natriuretic peptide (ANP) and the nitric oxide (NO) pathway. N(G)-nitro-L-arginine methyl ester bolus (L-NAME, 1 mg/kg) reverted the decrease in mean arterial pressure induced by ANP administration (5 microg/kg bolus and 0.2 microg x kg(-1) x min(-1) infusion), and the injection of L-NAME before peptide administration suppressed the ANP hypotensive response. To confirm these findings, a histochemical reaction was used to determine NADPH-diaphorase activity (a NO synthase marker) in the endothelium and smooth muscle of aorta and arterioles of the small and large intestine. ANP increased aorta and arteriole endothelium staining after both in vivo administration and in vitro tissue incubation. In both cases, L-NAME prevented the ANP effect on NADPH-diaphorase activity. Tissues incubated with 8-bromoguanosine 3',5'-cyclic monophosphate mimicked ANP action. In addition, ANP administration increased urinary excretion of NO(x) end products. These findings indicate that ANP increases NO synthesis capability and NO production and suggest that the cGMP pathway may be involved. In conclusion, the NO pathway could be an intercellular messenger in the ANP endothelium-dependent vasorelaxation mechanism.
Subject(s)
Atrial Natriuretic Factor/pharmacology , Atrial Natriuretic Factor/physiology , Blood Pressure/drug effects , Blood Pressure/physiology , Nitric Oxide/physiology , Animals , Enzyme Inhibitors/pharmacology , Male , NADPH Dehydrogenase/metabolism , NG-Nitroarginine Methyl Ester/pharmacology , Rats , Rats, WistarABSTRACT
Aortoenteric fistulas are a very unlikely cause of digestive bleeding. We present the case of a fifty six year old patient with a primary aortoduodenal fistula who consulted because of melena and a pulsating abdominal mass. He underwent three digestive endoscopies without arriving at any diagnosis. A computed axial tomography and an angiography showed an aneurysm of the abdominal aorta. With an exploring laparotomy a fistula was identified between the aneurysm and the fourth portion of the duodenum. An aortoaortic bypass was carried out followed by a surgical fix of the duodenum. The patient was released six days after the operation.
Subject(s)
Aortic Aneurysm, Abdominal/complications , Intestinal Fistula/complications , Aortic Aneurysm, Abdominal/diagnosis , Aortic Aneurysm, Abdominal/surgery , Humans , Intestinal Fistula/diagnosis , Intestinal Fistula/surgery , Male , Middle AgedABSTRACT
Aortoenteric fistulas are a very unlikely cause of digestive bleeding. We present the case of a fifty six year old patient with a primary aortoduodenal fistula who consulted because of melena and a pulsating abdominal mass. He underwent three digestive endoscopies without arriving at any diagnosis. A computed axial tomography and an angiography showed an aneurysm of the abdominal aorta. With an exploring laparotomy a fistula was identified between the aneurysm and the fourth portion of the duodenum. An aortoaortic bypass was carried out followed by a surgical fix of the duodenum. The patient was released six days after the operation.
ABSTRACT
Histochemical reaction of NADPH-diaphorase (NOS-NADPH-d) was used to identify NO synthesis. A 30-min 0.1 microg microg/kg/min ANP infusion led to about a 10% and 35% increase in small and large intestine enterocytes stain respectively. This increase was abolished by a bolus of 1 mg/kg L-NAME before ANP infusion in small intestine, and partially abolished it in colon. Incubation of small and large intestine with 0.5 microM ANP increased stain at about 20%. In both tissues the preincubation with 0.1 mM L-NAME abolished the ANP effect. Incubation with 0.1 mM 8-Br-cGMP enhanced staining about 70% and 30% in small and large intestine respectively. Our results show that ANP enhances NOS-NADPH-d activity, suggesting that ANP stimulates NO synthase in enterocytes by L-arginine-NO pathway. 8-Br-cGMP mimicked the effect of ANP described above. Therefore, the guanylate cyclase-coupled natriuretic receptors, NPR-A and NPR-B, probably mediate this ANP effect.
Subject(s)
Atrial Natriuretic Factor/pharmacology , Intestinal Mucosa/drug effects , NADPH Dehydrogenase/analysis , Nitric Oxide/biosynthesis , Animals , Colon/cytology , Colon/drug effects , Colon/enzymology , Cyclic GMP/analogs & derivatives , Cyclic GMP/pharmacology , Guanylate Cyclase/metabolism , Histocytochemistry , Image Processing, Computer-Assisted , Intestinal Mucosa/cytology , Intestinal Mucosa/enzymology , Intestine, Small/cytology , Intestine, Small/drug effects , Intestine, Small/enzymology , Isoenzymes , Male , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide Synthase , Photoperiod , Rats , Rats, Wistar , Receptors, Atrial Natriuretic Factor/metabolismABSTRACT
The aim of the present study was to elucidate the role of an IV dose of endothelin-3 (ET-3) (5 ng Kg-1 min-1) on mean arterial pressure (MAP), on diuresis and natriuresis in control and in volume expanded anesthetized rats. A systemic infusion of ET-3 in normal rats (Group I) increased MAP and produced a trend of increasing diuresis, without changes in natriuresis. A 10% body weight expansion (Group II) increased diuresis and natriuresis without changes in MAP. The simultaneous infusion of ET-3 and expansion with saline (Group III) resulted in an increase in MAP, an enhanced diuretic response, and a natriuresis of similar magnitude to that observed in Group II. These results suggest that the diuresis produced by a low dose of exogenous ET-3 in control rats, is independent of sodium excretion. Furthermore, the enhanced diuresis caused by ET-3 during expansion is greater than the addition of ET-3 and expansion effects, suggesting that new mechanisms are triggered in order to maintain volume and salt homeostasis in this state.
Subject(s)
Endothelin-3/physiology , Extracellular Space/metabolism , Sodium/metabolism , Water/metabolism , Animals , Blood Pressure/physiology , Cell Size/physiology , Diuresis/physiology , Male , Natriuresis/physiology , Rats , Rats, WistarABSTRACT
In vivo, atrial natriuretic peptide (ANP) inhibits water and sodium absorption by the intestine. In addition, ANP inhibits glucose (re)absorption at the level of both the intestine and kidney. ANP also decreases sodium absorption in the rat small intestine in vitro, but only if glucose is present on the luminal side of the tissue. These findings suggest that ANP inhibits the sodium-glucose cotransporter (SGLT) of enterocytes. In the present study the inhibitory effect of 1 microM ANP on SGLT1 in rat small intestine and colon was tested. For this purpose, the apparent kinetic constants of SGLT1 were determined using radioactive alpha-methyl-D-glucoside (alpha-MG), a non-metabolizable glucose analogue that selectively serves the luminal Na+-dependent intestinal uptake, but not the serosal-facilitated diffusion sugar carrier. In both tissues, incubation with ANP increased Km without modifying the Vmax. In addition, Vmax in the small intestine was found to be higher than in the colon. The evidence presented here suggests that ANP, through its second messenger, may be a competitive inhibitor of SGLT1. Since SGLT1 is also expressed in the brush-border membrane of the renal proximal tubule, we suggest that this peptide might regulate the hydro-saline balance at intestinal and proximal tubular nephron levels.