Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 40
Filter
2.
Hernia ; 28(2): 321-332, 2024 Apr.
Article in English | MEDLINE | ID: mdl-37725188

ABSTRACT

PURPOSE: This study aimed to perform a systematic review and meta-analysis comparing the efficacy and safety outcomes of robotic-assisted and laparoscopic techniques for incisional hernia repair. METHODS: PubMed, Embase, Scopus, Cochrane databases, and conference abstracts were systematically searched for studies that directly compared robot-assisted versus laparoscopy for incisional hernia repair and reported safety or efficacy outcomes in a follow-up of ≥ 1 month. The primary endpoints of interest were postoperative complications and the length of hospital stay. RESULTS: The search strategy yielded 2104 results, of which four studies met the inclusion criteria. The studies included 1293 patients with incisional hernia repairs, 440 (34%) of whom underwent robot-assisted repair. Study follow-up ranged from 1 to 24 months. There was no significant difference between groups in the incidence of postoperative complications (OR 0.65; 95% CI 0.35-1.21; p = 0.17). The recurrence rate of incisional hernias (OR 0.34; 95% CI 0.05-2.29; p = 0.27) was also similar between robotic and laparoscopic surgeries. Hospital length of stay (MD - 1.05 days; 95% CI - 2.06, - 0.04; p = 0.04) was significantly reduced in the robotic-assisted repair. However, the robot-assisted repair had a significantly longer operative time (MD 69.6 min; 95% CI 59.0-80.1; p < 0.001). CONCLUSION: The robotic approach for incisional hernia repair was associated with a significant difference between the two groups in complications and recurrence rates, a longer operative time than laparoscopic repair, but with a shorter length of stay.


Subject(s)
Hernia, Ventral , Incisional Hernia , Laparoscopy , Robotic Surgical Procedures , Humans , Incisional Hernia/surgery , Robotic Surgical Procedures/adverse effects , Robotic Surgical Procedures/methods , Herniorrhaphy/adverse effects , Herniorrhaphy/methods , Hernia, Ventral/surgery , Laparoscopy/adverse effects , Laparoscopy/methods , Postoperative Complications/epidemiology , Postoperative Complications/etiology , Postoperative Complications/surgery
3.
Bull Entomol Res ; 110(4): 438-448, 2020 Aug.
Article in English | MEDLINE | ID: mdl-31813400

ABSTRACT

The willow sawfly, Nematus oligospilus (Förster), is a pest in Salix commercial forests and has been reported worldwide. Female adults must recognize a suitable host plant to oviposit, since her offspring lack the ability to move to another host. We evaluated the effect of conspecific herbivory on the oviposition choices of N. oligospilus females by providing damaged (DP) and undamaged (UP) plants of Salix humboldtiana, a native willow from South America, as oviposition substrates. Local and systemic effects were studied. For the local treatment, a twig from the DP with damaged leaves was contrasted to a twig from a UP in dual choice experiments. For systemic treatment, a twig from the DP with intact leaves was contrasted to a twig from a UP. We estimated the use of olfactory and contact cues by comparing volatile emission of DP and UP, and by analysing the behaviour of the females during host recognition after landing on the leaf surface. In the context of the preference-performance hypothesis (PPH), we also tested if oviposition site selection maximizes offspring fitness by evaluating neonate hatching, larval performance and survival of larvae that were born and bred on either DP or UP. Our results demonstrate that previous conspecific herbivory on S. humboldtiana has a dramatic impact on female oviposition choices and offspring performance of the sawfly N. oligospilus. Females showed a marked preference for laying eggs on UP of S. humboldtiana. This preference was found for both local and systemic treatments. Volatile emission was quantitatively changed after conspecific damage suggesting that it could be related to N. oligospilus avoidance. In the dual choice preference experiments, the analysis of the behaviour of the females once landing on the leaf surface suggested the use of contact cues triggering egg laying on leaves from UP and avoidance of leaves from DP. Furthermore, 48 h of previous conspecific feeding was sufficient to dramatically impair neonate hatching, as well as larval development and survival, suggesting a rapid and effective reaction of the induced resistance mechanisms of the tree. In agreement with the PPH, these results support the idea that decisions made by colonizing females may result in optimal outcomes for their offspring in a barely studied insect model, and also opens the opportunity for studying tree-induced defences in the unexplored South American willow S. humboldtiana.


Subject(s)
Hymenoptera/physiology , Oviposition/physiology , Salix , Animals , Behavior, Animal/physiology , Choice Behavior , Female , Herbivory , Hymenoptera/growth & development , Larva/growth & development , Odorants , Plant Leaves/chemistry , Salix/chemistry , Volatile Organic Compounds/analysis
4.
Neotrop Entomol ; 45(6): 712-717, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27299866

ABSTRACT

Food webs are usually regarded as snapshots of community feeding interactions. Here, we describe the yearly and cumulative structure of parasitoid-caterpillar food webs on soybean in central Argentina, analyzing parasitism rates and their variability in relation to parasitoid diversity and food web vulnerability in the system. Lepidoptera larvae were collected along four seasons from soybean crops and reared in laboratory to obtain and identify adults and parasitoids. Eleven species of defoliating Lepidoptera and ten parasitoid species were recorded. Food web statistics showed rather low annual variability, with most variation coefficients in the order of 0.20 and generality showing the most stable values. Parasitism showed the highest variability, which was independent of parasitoid diversity and food web vulnerability, although parasitism rates were negatively related to parasitoid richness. Our study highlights the need to consider food web structure and variability in order to understand the functioning of ecological communities in general and in extensive agricultural ecosystems in particular.


Subject(s)
Glycine max , Host-Parasite Interactions , Lepidoptera/parasitology , Animals , Argentina , Food Chain
5.
Bull Entomol Res ; 105(6): 685-93, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26344662

ABSTRACT

Studies on insect natural enemies and their effects on host populations are of immense practical value in pest management. Predation and parasitism on a citrus pest, the leafminer Phyllocnistis citrella Stainton, were evaluated by sampling over 3 years in four locations within a world leading lemon producing area in Northwest Argentina. Both mortality factors showed seasonal trends consistent across locations, with predation exerting earlier and more sustained pressure than parasitism, which showed wider seasonal variations. The dominant parasitoids, native Cirrospilus neotropicus and introduced Ageniaspis citricola, showed different seasonal trends: C. neotropicus was dominant in spring whereas A. citricola superseded it in autumn and winter. Although parasitism rates were relatively low, the native C. neotropicus revealed favourable features as potential control agent, by showing density-dependence, parasitism rates comparable with those of the specific A. citricola during part of the cycle, and earlier synchronization with the host. The study provides highly relevant information for a sustainable management of this worldwide pest, for which biological control is considered the best long-term option.


Subject(s)
Citrus/physiology , Moths , Pest Control, Biological , Seasons , Animals , Argentina , Host-Parasite Interactions , Population Density , Population Dynamics
6.
Epidemiol Infect ; 142(11): 2251-60, 2014 Nov.
Article in English | MEDLINE | ID: mdl-24480252

ABSTRACT

Isolates of Listeria monocytogenes (n = 932) isolated in Sweden during 1958-2010 from human patients with invasive listeriosis were characterized by serotyping and pulsed-field gel electrophoresis (PFGE) (AscI). Of the 932 isolates, 183 different PFGE types were identified, of which 83 were each represented by only one isolate. In all, 483 serovar 1/2a isolates were distributed over 114 PFGE types; 90 serovar 1/2b isolates gave 32 PFGE types; 21 serovar 1/2c isolates gave nine PFGE types; three serovar 3b isolates gave one PFGE type; and, 335 serovar 4b isolates gave 31 PFGE types. During the 1980s in Sweden, several serovar 4b cases were associated with the consumption of European raw soft cheese. However, as cheese-production hygiene has improved, the number of 4b cases has decreased. Since 1996, serovar 1/2a has been the dominant L. monocytogenes serovar in human listeriosis in Sweden. Therefore, based on current serovars and PFGE types, an association between human cases of listeriosis and the consumption of vacuum-packed gravad and cold-smoked salmon is suggested.


Subject(s)
Food Contamination/statistics & numerical data , Listeria monocytogenes/classification , Listeriosis/epidemiology , Salmon , Adolescent , Adult , Age Distribution , Aged , Aged, 80 and over , Animals , Child , Child, Preschool , Databases, Factual , Electrophoresis, Gel, Pulsed-Field/methods , Female , Food Contamination/prevention & control , Humans , Infant , Listeria monocytogenes/pathogenicity , Listeriosis/diagnosis , Male , Middle Aged , Pregnancy , Prevalence , Retrospective Studies , Risk Assessment , Seafood/adverse effects , Seafood/analysis , Serotyping/methods , Sex Distribution , Sweden/epidemiology , Time Factors , Young Adult
7.
Int J Food Microbiol ; 166(1): 186-92, 2013 Aug 16.
Article in English | MEDLINE | ID: mdl-23911759

ABSTRACT

Identification and prioritisation of food safety interventions requires an understanding of the relationship between food, pathogens and cases. Such understanding can be gained through different approaches, e.g. microbial subtyping to attribute cases of foodborne disease to food vehicles or other sources of illness. In this study, Listeria monocytogenes isolates (n=166) from (i) three categories of ready-to-eat (RTE) foods, (ii) food processing plant environments, and (iii) human listeriosis cases, all sampled during 2010 in Sweden, were subtyped. In addition, 121 isolates from human listeriosis cases, collected 2005-2009, were subtyped. Subtyping consisted of both serotyping (conventional method and PCR) and genotyping using pulsed-field gel electrophoresis (PFGE). Serotype 1/2a dominated in all three groups of isolates (range 73-96%). Eighteen percent of the human isolates (2010) belonged to serotype 4b, but only 1.4% of the food isolates. The food isolates differentiated into 19 pulsotypes (ID=0.843), the human isolates collected 2010 into 31 pulsotypes (ID=0.950) and the processing plant isolates into 22 pulsotypes (ID=0.991). Six of the pulsotypes were shared between the food and human isolates. These pulsotypes comprised 42% of the human isolates and 59% of the food isolates. For some processing plants, there was suggested persistence of one or more specific L. monocytogenes strains, as indicated by repetitive isolation of the same pulsotype from food. This study indicated the presence of L. monocytogenes in the processing plant environment as a likely source of contamination of gravad and cold-smoked fish, and this food category as an important source of human exposure to the pathogen.


Subject(s)
Environmental Microbiology , Food Microbiology , Listeria monocytogenes/classification , Listeriosis/microbiology , Aged , Animals , Electrophoresis, Gel, Pulsed-Field , Female , Food Handling , Genotype , Humans , Listeria monocytogenes/genetics , Listeria monocytogenes/isolation & purification , Listeriosis/epidemiology , Male , Polymerase Chain Reaction , Serotyping , Sweden/epidemiology
10.
Bioresour Technol ; 99(8): 3066-70, 2008 May.
Article in English | MEDLINE | ID: mdl-17669645

ABSTRACT

Aedes aegypti (L.) (Diptera: Culicidae), the main urban vector of dengue, has developed resistance to various insecticides, making its control increasingly difficult. We explored the effects of Argentine Melia azedarach L. (Meliaceae) fruit and senescent leaf extracts on Ae. aegypti larval development and survival, by rearing cohorts of first instar mosquitoes in water with different extract concentrations. We also analysed oviposition deterrent activity in choice tests with extract-treated ovitraps. The leaf extract showed a strong larvicide activity, with all larvae dying before pupation, and significantly delayed development time. It strongly inhibited oviposition by Ae. aegypti females. The fruit extract showed much weaker effects. This first report of highly effective larvicidal, growth regulating and oviposition deterrent activity of a senescent leaf extract of M. azedarach against Ae. aegypti, suggests that such extract could represent a promising tool in the management of this mosquito pest.


Subject(s)
Aedes/growth & development , Azadirachta/chemistry , Larva/drug effects , Oviposition/drug effects , Plant Extracts/pharmacology , Aedes/drug effects , Animals , Argentina , Dengue/prevention & control , Female , Fruit , Humans , Insecticide Resistance , Plant Leaves
11.
Rev Esp Anestesiol Reanim ; 54(7): 436-9, 2007.
Article in Spanish | MEDLINE | ID: mdl-17953338

ABSTRACT

Paroxysmal supraventricular tachycardia is the most common tachyarrhythmia in childhood and adolescence. The current treatment of choice for managing and preventing frequent recurrences is radiofrequency catheter ablation, which provides a definitive solution in most cases. This technique is very effective but not devoid of potential complications, particularly in children and adolescents. We report the case of a 3-year-old girl who suffered acute myocardial infarction after occlusion of the right coronary artery during this procedure. We describe intraoperative and postoperative management. Progress was good and the patient was discharged 14 days after ablation.


Subject(s)
Catheter Ablation/adverse effects , Coronary Vessels/injuries , Intraoperative Complications/etiology , Myocardial Infarction/etiology , Tachycardia, Paroxysmal/surgery , Tachycardia, Supraventricular/surgery , Cardiopulmonary Resuscitation , Cardiotonic Agents/therapeutic use , Child, Preschool , Combined Modality Therapy , Dobutamine/therapeutic use , Female , Humans , Hypotension/etiology , Myocardial Infarction/diagnosis , Myocardial Infarction/drug therapy , Myocardial Infarction/therapy , Nitroglycerin/therapeutic use , Postoperative Complications/etiology , Vasodilator Agents/therapeutic use
12.
Rev. esp. anestesiol. reanim ; 54(7): 436-439, ago.-sept. 2007. ilus, tab
Article in Es | IBECS | ID: ibc-62293

ABSTRACT

La taquicardia paroxística supraventricular es lataquiarritmia más frecuente en la infancia y adolescencia.Actualmente el tratamiento de elección para el controly prevención de las frecuentes recidivas es la ablacióntranscatéter por radiofrecuencia, logrando en lamayoría de los casos una solución definitiva del problema.Esta técnica es muy eficaz pero no está exenta deposibles complicaciones, sobre todo en niños y adolescentes.Presentamos el caso de una niña de tres años coninfarto agudo de miocardio tras oclusión de la arteriacoronaria derecha en el transcurso de la ablación transcatéterpor radiofrecuencia. Se muestra el manejo intraoperatorioy postoperatorio en reanimación. La niñaevolucionó favorablemente y pudo ser dada de alta hospitalariaa los 14 días del procedimiento (AU)


Paroxysmal supraventricular tachycardia is the most common tachyarrhythmia in childhood and adolescence. The current treatment of choice for managing and preventing frequent recurrences is radiofrequency catheter ablation, which provides a definitive solution in most cases. This technique is very effective but not devoid of potential complications, particularly in children and adolescents. We report the case of a 3-yearold girl who suffered acute myocardial infarction after occlusion of the right coronary artery during this procedure. We describe intraoperative and postoperative management. Progress was good and the patient was discharged 14 days after ablation (AU)


Subject(s)
Humans , Female , Child, Preschool , Tachycardia, Paroxysmal/therapy , Catheter Ablation/adverse effects , Myocardial Infarction/etiology , Tachycardia, Paroxysmal/complications , Myocardial Infarction/therapy , Cardiopulmonary Resuscitation , Coronary Disease/complications
13.
Epidemiol Infect ; 135(5): 854-6, 2007 Jul.
Article in English | MEDLINE | ID: mdl-17109771

ABSTRACT

Two variants of Listeria monocytogenes were isolated from blood cultures from each of two patients with listeriosis. Each variant displayed a two-band difference in DNA profile from the other by pulsed-field gel electrophoresis. Although this difference in profile is insufficient to distinguish clearly between the variants, the possibility of co-infection with different strains of L. monocytogenes needs to be considered. We suggest that more than one colony should be selected for molecular typing to aid interpretation during investigation of the sources and routes of Listeria infection.


Subject(s)
Listeria monocytogenes/classification , Listeriosis/microbiology , DNA, Bacterial/analysis , Electrophoresis, Gel, Pulsed-Field , Humans , Listeria monocytogenes/genetics
14.
Fitoterapia ; 77(7-8): 500-5, 2006 Dec.
Article in English | MEDLINE | ID: mdl-16889905

ABSTRACT

In laboratory choice and no-choice bioassays, treatment of elm leaves with extracts obtained from unripe fruits and green or senescent leaves of Melia azedarach at 1-10% concentration significantly deterred feeding by adults of the elm leaf beetle, Xanthogaleruca luteola. Also, in no-choice tests, adults fed on leaves treated with 2, 5 or 10% extract showed a dramatic increase in mortality rates. Extracts from the different plant structures were similarly active, and starvation as a consequence of their strong antifeedant activity could play a significant role in the high mortality values observed.


Subject(s)
Coleoptera/physiology , Feeding Behavior/drug effects , Insecticides/pharmacology , Melia azedarach , Pest Control, Biological , Phytotherapy , Plant Extracts/pharmacology , Animals , Coleoptera/drug effects , Fruit , Insecticides/administration & dosage , Plant Extracts/administration & dosage , Plant Leaves
15.
Rev. chil. pediatr ; 76(1): 25-33, ene.-feb. 2005. tab, graf
Article in Spanish | LILACS | ID: lil-432953

ABSTRACT

Desde el año 2001, SAPU Colina ha implementado un sistema triage de atención. En Chile, no existen estudios que determinen la efectividad de este tipo de atención. Objetivo: Determinar la capacidad de este sistema para atender en menor tiempo a los más graves. Pacientes y Método: Estudio descriptivo de 46 014 atenciones a menores de 15 años subdivididos en tres prioridades (P1, P2 y P3) de gravedad decreciente, en el período julio 2002-junio 2003. Se definieron: tiempo de espera, gravedad y triage efectivo. Se describen los tiempos de espera y las derivaciones realizadas. Se determinan los pacientes atendidos en Colina y posteriormente en su hospital base (SUHRR), describiéndose los pacientes hospitalizados. Resultados: La mediana de tiempos de espera fue para P1: 22 min, P2: 32 min, P3: 64 min, para los derivados fue de 22 min y 39 min para los no derivados. La proporción atendida dentro de los primeros 30 minutos fue: P1: 75,5 por ciento; P2: 53,2 por ciento; P3: 25,8 por ciento, para los derivados fue de 64 por ciento y 39 por ciento en los no derivados. La proporción de pacientes hospitalizados del total de atenciones en SAPU fue significativamente mayor en P1: 6,88 por ciento (n = 48) que P2: 2,47 por ciento (n = 35) y que en P3: 0,6 por ciento (n = 15). Conclusión: Este sistema permite que los pacientes de mayor gravedad sean atendidos con tiempos de espera menor.


Subject(s)
Adolescent , Humans , Infant, Newborn , Infant , Child, Preschool , Child , Primary Health Care , Delivery of Health Care/statistics & numerical data , Delivery of Health Care/organization & administration , Emergency Medical Services/organization & administration , Triage , Chile , Epidemiology, Descriptive , Hospitalization/statistics & numerical data , Delivery of Health Care/methods , Referral and Consultation/statistics & numerical data , Waiting Lists
16.
Rev. Soc. Esp. Dolor ; 11(2): 82-86, mar. 2004. ilus, tab
Article in Es | IBECS | ID: ibc-31479

ABSTRACT

Introducción: El bloqueo del nervio ciático en la fosa poplítea proporciona una adecuada y prolongada analgesia postoperatoria en la cirugía del pie y tobillo. La principal ventaja del abordaje lateral es que no es preciso modificar la posición de decúbito supino del paciente para la realización de la técnica, mientras que en el abordaje posterior el paciente ha de colocarse en decúbito prono, lo cual puede resultar difícil e incluso desaconsejable en determinadas situaciones: estados avanzados de gestación, inestabilidad hemodinámica y ventilación mecánica. Material y método: Se incluyeron pacientes valorados con riesgo anestésico ASA I-II, programados para cirugía ortopédica-traumatológica del pie o tobillo. Se realizó un bloqueo del nervio ciático en la fosa poplítea mediante abordaje lateral según la técnica descrita por Vloka J.D y Hadzic A, empleándose una aguja para neuroestimulación, biselada de calibre 22G x 80 mm. Se consideró como respuesta motora adecuada cualquier movimiento del pie o dedos a intensidad inferior a 0,4 mA y superior a 0,1 mA. La observación de una respuesta motora a intensidad de estimulación de 0,1 mA se consideró como localización intraneural de la aguja. Se inyectaron 40 mL de ropivacaína 0,5 por ciento. Las principales variables que se registraron a las 8, 16 y 24 horas tras la realización del bloqueo fueron el dolor en reposo y en movimiento según la escala visual analógica (EVA) de 0-10 y el grado de satisfacción. Resultados: Se incluyeron 21 pacientes ASA I-II. El dolor medio en reposo fue valorado como de intensidad 1 en las primeras 8 horas y de intensidad 3 a las 16 h y 24 h tras la realización del bloqueo. El dolor medio con el movimiento articular fue valorado como de intensidad 2 a las 8 h y de intensidad 4 a las 16 h y 24 h tras el bloqueo. El grado de satisfacción medio referido por los pacientes fue de 9.Discusión: El abordaje lateral, como en la serie que presentamos, nos permitió realizar la técnica sin necesidad de modificar la posición de decúbito supino que mantenían todos los pacientes. Es de destacar la excelente calidad analgésica proporcionada por el bloqueo del nervio ciático en la fosa poplítea mediante abordaje lateral en la serie que presentamos, tanto en reposo como con el movimiento del pie. En conclusión, el bloqueo del nervio ciático en la fosa poplítea mediante abordaje lateral con 40 mL de ropivacaína 0,5 por ciento proporciona, en la cirugía del pie y tobillo, una analgesia postoperatoria eficaz, prolongada, sin efectos indeseables y con alto grado de satisfacción del paciente (AU)


Subject(s)
Adolescent , Adult , Aged , Middle Aged , Humans , Postoperative Care , Foot Diseases/surgery , Ankle Injuries/surgery , Nerve Block/methods , Analgesia/methods , Sciatic Nerve , Patient Satisfaction
17.
Rev. Soc. Esp. Dolor ; 11(1): 21-25, ene. 2004. tab
Article in Es | IBECS | ID: ibc-31149

ABSTRACT

Introducción: El objetivo del estudio es conocer el grado de dolor y satisfacción en el postoperatorio de los pacientes que han recibido analgesia mediante bloqueo femoral continuo en artroplastia total de rodilla. Material y método: Se incluyeron pacientes ASA I-III diagnosticados de gonartrosis e intervenidos de artroplastia total de rodilla bajo anestesia intradural. En la Sala de Despertar y bajo los efectos residuales de la anestesia intradural se colocó un catéter en la proximidad del nervio femoral, con neuroestimulación. Se administró un bolo inicial de ropivacaína 0,375 por ciento 30 ml, seguido de una perfusión continua de ropivacaína 0,125 por ciento 10 ml.h-1, que se mantuvo durante las primeras 48 horas del postoperatorio. Las variables registradas fueron las siguientes: dolor postoperatorio a las 24 y 48 horas mediante EVA, localización del dolor, existencia o no de bloqueo motor, parestesias-disestesias y efectos secundarios, así como fármacos utilizados en caso de analgesia insuficiente, dificultad de la técnica y grado de satisfacción a las 48 horas. Resultados: Se incluyeron 8 pacientes, con peso y altura media de 78 kg y 157 cm respectivamente. El análisis del dolor registrado a las 24 horas fue en un 62,5 por ciento de EVA 0, en un 25 por ciento EVA 5 y en un 12,5 por ciento EVA 6. A las 48 horas el 87,5 por ciento de los pacientes tenían un EVA 0 y un 12,5 por ciento EVA 4. Todos los pacientes con dolor lo localizaron en hueco poplíteo. En ningún caso hubo bloqueo motor. El 25 por ciento presentaron parestesias a las 24-48 horas y el 12,5 por ciento episodio de náuseas. En caso de analgesia insuficiente se complementó el tratamiento con AINE intravenosos y en un caso con bloqueo del nervio ciático por abordaje anterior. La técnica realizada resultó fácil en el 87,5 por ciento de los pacientes y muy difícil en el 12,5 por ciento. El grado de satisfacción fue superior a 7 en todos los pacientes. Conclusiones: El bloqueo 3 en 1 continuo en nuestra serie, proporcionó una analgesia eficaz en pacientes intervenidos de artroplastia total de rodilla, constituyendo una técnica fácil de realizar, con un elevado grado de satisfacción en los pacientes estudiados (AU)


Subject(s)
Humans , Knee Injuries/surgery , Pain, Postoperative/drug therapy , Analgesia/methods , Arthroplasty, Replacement, Knee , Patient Satisfaction , Pain Measurement , Anesthetics, Local , Femoral Nerve
18.
Life Sci ; 68(25): 2813-24, 2001 May 11.
Article in English | MEDLINE | ID: mdl-11432447

ABSTRACT

It has been shown that all-trans retinoic acid induces prematurely hepatic glucokinase mRNA in ten days-old neonatal rat hepatocytes, however, this effect could be related to the capacity of the retinoid to promote a more differentiated state of the hepatocyte. In this report we demonstrate that physiological concentrations of all-trans retinoic acid stimulate glucokinase activity in both mature fully differentiated hepatocytes and at the onset of the induction of the enzyme in 15 to 17 days-old neonatal hepatocytes. The effects produced by the retinoid were similar both in magnitude and in time, to those elicited by insulin, a well-known stimulator of hepatic glucokinase expression. No additive effect was observed when insulin and retinoic acid were tested together. Using the branched DNA assay, a sensitive signal amplification technique, we detected relative increases in glucokinase mRNA levels of about 70% at 3 and 24 h after the treatment with 10(-6) M all-trans retinoic acid, in both neonatal and adult hepatocytes. These data show that retinoic acid exerts a stimulatory effect on hepatic glucokinase independent of the hepatocyte stage of maturity and suggest a physiological role of retinoic acid on glucose metabolism. The action of retinoic acid on hepatic glucokinase might explain previous observations on the relationship between vitamin A status and liver glycogen synthesis. These findings may serve as basis for further investigations on the biological functions of retinoic acid derivatives on hepatic glucose metabolism.


Subject(s)
Gene Expression/drug effects , Glucokinase/biosynthesis , Hepatocytes/drug effects , Hepatocytes/enzymology , Tretinoin/pharmacology , Animals , Animals, Newborn , Animals, Suckling , Cells, Cultured , Dose-Response Relationship, Drug , Drug Interactions , Enzyme Induction/drug effects , Glucokinase/genetics , Insulin/pharmacology , Liver/drug effects , Liver/enzymology , RNA, Messenger/metabolism , Rats , Rats, Wistar
19.
Endocrinology ; 140(10): 4595-600, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10499515

ABSTRACT

Biotin has been reported to affect glucose homeostasis; however, its role on pancreatic islets of Langerhans has not been assessed. In this report, we demonstrate that physiologic concentrations of biotin stimulate glucokinase activity in rat islets in culture. Using the branched DNA (bDNA) assay, a sensitive signal amplification technique, we detected relative increases in glucokinase mRNA levels of 41.5 +/- 13% and 81.3 +/- 19% at 12 and 24 h respectively in islets treated with [10(-6) M] biotin. Because glucokinase activity controls insulin secretion, we also investigated the effect of biotin on insulin release. Treatment with [10(-6) M] biotin for 24 h increased insulin secretion. We extended our studies by analyzing the effect of biotin deficiency on pancreatic islet glucokinase expression and activity, as well as insulin secretion. Our results show that islet glucokinase activity and mRNA are reduced by 50% in the biotin deficient rat. Insulin secretion in response to glucose was also impaired in islets isolated from the deficient rat. These data show that biotin affects pancreatic islet glucokinase activity and expression and insulin secretion in cultured islets.


Subject(s)
Biotin/deficiency , Biotin/physiology , Glucokinase/metabolism , Insulin/metabolism , Pancreas/metabolism , Animals , Biotin/pharmacology , Cells, Cultured , Glucokinase/genetics , Insulin Secretion , Male , Pancreas/drug effects , Pancreas/enzymology , RNA, Messenger/metabolism , Rats , Rats, Wistar
20.
Endocrinology ; 140(7): 3091-6, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10385401

ABSTRACT

Retinoic acid has manifold effects on pancreatic beta-cells. Previously we reported that retinoic acid increases glucokinase activity and messenger RNA (mRNA) levels in the insulinoma cell line RIN-m5F; however, we could not rule out the possibility that the effect of retinoic acid on RIN-m5F glucokinase was inherent to the cell line or related to its differentiating capacity. In this report, we demonstrate that physiologic concentrations of retinoic acid stimulate glucokinase activity in both fetal islets and differentiated adult islets in culture. In the adult tissue, the response to the retinoid was less pronounced, achieving about half of the maximal effect produced on the fetal tissue. Using the branched DNA (bDNA) assay, a sensitive signal amplification technique, we detected relative increases in glucokinase mRNA levels of 51.8+/-13.3% and 62.8+/-16.1% at 12 and 24 h, respectively, in adult islets treated with] 10(-6) M retinoic acid. In fetal islets, increases of 55+/-14.9% and 107+/-30.5% at 12 and 24 h, respectively, were observed. In transfected fetal islets, retinoic acid increased the activity of the -1000 kb rat glucokinase promoter by 51.3%. Because glucokinase activity controls insulin secretion, we also investigated the effect of retinoic acid on insulin secretion. Treatment with 10(-6) M retinoic acid for 24 h increased insulin secretion in both fetal and adult islets; however, the increases on insulin secretion were more pronounced in the mature islets; in contrast, retinoic acid produced higher levels of insulin mRNA in the fetal islets. These data show that retinoic acid increases pancreatic glucokinase in cultured islets and that the mechanism may involve a stimulatory effect on the glucokinase promoter.


Subject(s)
Glucokinase/genetics , Glucokinase/metabolism , Insulin/metabolism , Islets of Langerhans/physiology , Tretinoin/pharmacology , Animals , Culture Techniques , Fetus/metabolism , Gene Expression/physiology , Insulin/genetics , Insulin Secretion , Islets of Langerhans/embryology , Islets of Langerhans/enzymology , Islets of Langerhans/metabolism , Male , Promoter Regions, Genetic/drug effects , Promoter Regions, Genetic/physiology , RNA, Messenger/metabolism , Rats/embryology , Rats, Wistar
SELECTION OF CITATIONS
SEARCH DETAIL
...