RESUMEN
Increased expression of endothelin converting enzyme-1 (ECE-1) is associated with diabetic nephropathy. The molecular mechanisms underlying this association, as yet unknown, possibly involve protein kinase C (PKC) pathways. In the present study, we examined the effects of high glucose and PKC activation on ECE-1 expression in primary human umbilical vein endothelial cells (HUVECs) and in HUVEC line (EA.hy926). Increasing glucose concentration, but not mannitol, from 5.5-22.2 mmol/liter for 3 d, enhanced prepro endothelin-1 (ET-1) mRNA expression, ET-1 levels, ECE-1 protein, and mRNA expressions by 7, 4, 20, and 2.6-fold, respectively. High glucose increased ECE-1 protein expression dose and time dependently. By Western blot analysis, PKC-beta1, -beta2, and -delta isoform levels were significantly increased relative to other isoforms when glucose level was increased. Treatment with Rottlerin, a PKC-delta isoform inhibitor, reduced significantly the glucose-induced ET-1 secretion, and ECE-1 protein expression, but (S)-13-[(dimethylamino)methyl]-10,11,14,15-tetrahydro-4,9:16,21-dimetheno 1H,1(3)H-dibenzo[e,k]pyrrolo[3,4-h] (1, 4, 3) oxadiaza-cyclohexadecene-1,3(2H)-dione or Gö6976, specific PKC-beta and -alpha inhibitors, respectively, did not. Overexpression of PKC-delta but not PKC-alpha or -beta1 isoforms by adenovirus vector containing the respective cDNA in HUVECs incubated with 5.5 mmol/liter glucose, increased in parallel PKC proteins, and glucose-induced endothein-1 and ECE-1 protein expression by 4- to 6-fold. These results show that enhanced ECE-1 expression induced by hyperglycemia is partly due to activation of the PKC-delta isoform. Thus, inhibition of this PKC isoform may prevent diabetes-related increase in ET-1.
Asunto(s)
Ácido Aspártico Endopeptidasas/genética , Metaloendopeptidasas/genética , Proteína Quinasa C/fisiología , Ácido Aspártico Endopeptidasas/metabolismo , Células Cultivadas , Diabetes Mellitus/genética , Diabetes Mellitus/metabolismo , Relación Dosis-Respuesta a Droga , Endotelina-1/genética , Endotelina-1/metabolismo , Enzimas Convertidoras de Endotelina , Endotelinas/genética , Endotelinas/metabolismo , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Glucosa/farmacología , Humanos , Hiperglucemia/enzimología , Hiperglucemia/genética , Hiperglucemia/metabolismo , Isoenzimas/antagonistas & inhibidores , Isoenzimas/genética , Isoenzimas/metabolismo , Metaloendopeptidasas/metabolismo , Proteína Quinasa C/antagonistas & inhibidores , Proteína Quinasa C/genética , Proteína Quinasa C/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Especificidad por SustratoRESUMEN
Even though certain health needs of gay, lesbian, and bisexual (GLB) patients are unique and different from those of the heterosexual patient, physicians do not usually ask patients about their sexual orientation. This study investigates family physicians' common practice regarding their patients' sexual orientation. Most of the physicians surveyed knew of less than 0.5% GLB patients in their practice; 44.4% did not know of any GLB patients. Only one physician commonly asked his patients about their sexual orientation; other physicians rarely or never asked. Asking patients about their sexual orientation significantly (P < 0.01) predicted the number of GLB patients known to the physician. Asking about patients' sexual orientation is not a common practice for family physicians, and, thus, they are usually unaware of the GLB patients in their practice.
Asunto(s)
Medicina Familiar y Comunitaria , Pautas de la Práctica en Medicina , Conducta Sexual , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Relaciones Médico-Paciente , Médicos de Familia , Encuestas y CuestionariosRESUMEN
Many drugs are not able to enter the brain due to the presence of the blood-brain barrier (BBB) and therefore cannot be used in the treatment of diseases of the brain. Since it is now known that the brain is under immunological surveillance, we hypothesized that phagocytic cells of the innate immune system, mainly neutrophils and monocytes, can be exploited as transporters of drugs to the brain. To target circulating mononuclear phagocytic cells, negatively-charged nano-sized liposomes were formulated encapsulating serotonin, a BBB impermeable neurological drug. Brain uptake, biodistribution, and the mechanism of brain transport were examined in vitro and in rats and rabbits by utilizing double-radiolabeled (3)H (in the membrane) and (14)C-serotonin (in the core), and liposomes with fluorescent markers (membrane and core). The brain uptake of liposomal serotonin was significantly higher (0.138%+/-0.034 and 0.097%+/-0.011, vs. 0.068%+/-0.02 and 0.057%+/-0.01, 4 h and 24 h after IV administration in rats, serotonin liposomes and in solution, respectively). The same brain uptake of both empty and serotonin liposomes, the co-localization in the brain of both markers, and the unchanged ratio of (3)H:(14)C suggest that intact liposomes entered the brain. Since treatment of animals by liposomal alendronate resulted with inhibition of monocytes but not of neutrophils, and with no brain delivery, it is suggested that monocytes are the main transporters of liposomes to the brain.
Asunto(s)
Encéfalo/metabolismo , Liposomas/farmacocinética , Monocitos/metabolismo , Fagocitosis/fisiología , Serotonina/administración & dosificación , Animales , Química Encefálica , Movimiento Celular/fisiología , Colesterol/química , Sistemas de Liberación de Medicamentos/métodos , Endocitosis/fisiología , Humanos , Inyecciones Intravenosas , Liposomas/química , Liposomas/metabolismo , Masculino , Monocitos/citología , Monocitos/fisiología , Neutrófilos/citología , Neutrófilos/metabolismo , Neutrófilos/fisiología , Fosfatidilcolinas/química , Fosfatidilgliceroles/química , Conejos , Ratas , Ratas Sprague-Dawley , Serotonina/metabolismo , Serotoninérgicos/administración & dosificación , Serotoninérgicos/metabolismo , Distribución TisularRESUMEN
OBJECTIVES: To measure knowledge of Israeli low back pain (LBP) clinical practice guidelines among different subgroups of primary care doctors, prior to designing an intervention programme to enhance guideline adherence in practice. STUDY DESIGN: Confidential mailed survey questionnaire. SETTING: Family practices in the Haifa and western Galilee district, Israel. PARTICIPANTS: Random sample of 163 primary care doctors. A total of 134 doctors (82%) completed the questionnaire. MAIN OUTCOME MEASURES: A Multiple Choice Questionnaire measuring knowledge of the LBP guidelines. Instrument reliability and inter-item reliability were tested in a pilot phase. Content validity was assured by having the Israeli LBP guideline authors involved in a consensus procedure. RESULTS: Distribution of test scores significantly differentiated professional levels and background variables, demonstrating the instrument reliability. Cronbach's alpha was above 0.91. The average test score was 67.7 [standard deviation (SD) 16.2], family doctors had average scores of 75.2 (SD 9.8), general practitioners (GPs) 57.9 (SD 19) and family practice residents 67.4 (SD 13.2). The difference between the test average scores of family doctors, GPs and residents was significant (P < 0.001). Significant differences were also found for specific variables including the doctor's age, country of medical training and self-report familiarity with the LBP guidelines. CONCLUSIONS: Striking differences exist between subgroups of primary care doctors regarding their knowledge of LBP guidelines. These differences will require the design of multiple interventions tailored to each subgroup.
Asunto(s)
Competencia Clínica/normas , Adhesión a Directriz/organización & administración , Conocimientos, Actitudes y Práctica en Salud , Dolor de la Región Lumbar , Médicos de Familia/educación , Guías de Práctica Clínica como Asunto , Adulto , Análisis de Varianza , Actitud del Personal de Salud , Evaluación Educacional , Medicina Basada en la Evidencia/educación , Femenino , Humanos , Israel , Dolor de la Región Lumbar/diagnóstico , Dolor de la Región Lumbar/terapia , Masculino , Persona de Mediana Edad , Evaluación de Necesidades , Médicos de Familia/organización & administración , Médicos de Familia/psicología , Pautas de la Práctica en Medicina/organización & administración , Atención Primaria de Salud/organización & administración , Estadísticas no Paramétricas , Encuestas y CuestionariosRESUMEN
BACKGROUND: The decline in the number of medical students who choose a residency in family medicine may cause a shortage of family physicians. The choice of a medical career is a complex process influenced by many interwoven factors. OBJECTIVES: To find out the level of interest in a residency in family medicine among medical students in one faculty of medicine in Israel (Technion) and to identify the factors related to family medicine preference. METHODS: A self administered questionnaire was distributed to medical students at the Technion. The students were asked to indicate their career choices and to rank the importance of 30 statements with regard to their choice. Factor analysis was performed to examine similar variables. A logistic regression was performed to examine the variables that predict family medicine choice. RESULTS: Of 496 students, 358 (72%) completed the questionnaire; 5.6% chose family medicine as a first residency option, and 24.9% chose it as one of their 3 first options. Research findings show that gender (female), marital status (non-single), religion (Jewish) and lack of previous health-related experience, predicted family medicine choice. The students that chose family medicine were more concerned with medical lifestyle, patients' population characteristics and societal commitment. CONCLUSIONS: The number of students that prefer a residency in family medicine is low. Several factors predict family medicine preference. Correct identification of these factors could enable interventions to increase the number of students choosing family medicine. The current study should be continued at the Technion and should also be carried out in other faculties.
Asunto(s)
Medicina Familiar y Comunitaria , Medicina , Especialización , Estudiantes de Medicina , Adolescente , Adulto , Selección de Profesión , Conducta de Elección , Femenino , Humanos , Internado y Residencia , Israel , Masculino , Facultades de Medicina , Estudiantes de Medicina/psicología , Encuestas y Cuestionarios , Adulto JovenRESUMEN
Gay, lesbian, bisexual and transgender (GLBT) patients have unique and different health needs other then those of the heterosexual patient. Although a significant proportion of the population is gay or lesbian, physicians receive little formal training about homosexuality, and the unique health care needs of these patients are often ignored. GLBT patients may have higher rates of depression, suicide attempts, alcoholism, and certain cancers, sexual transmitted and cardiovascular disease. One of the most significant medical risks of these populations is avoidance of routine health care and dissatisfaction due to fear of stigmatization by the medical community. Youth GBLT patients are particularly vulnerable to internal and external pressures, resulting in higher rates of substance and alcohol abuse, suicide, and homelessness. Declining health and loneliness may trouble older GBLT patients, who generally view themselves more positively. Physicians can improve the health care of GBLT patients and their families by maintaining a non-homophobic attitude toward these patients, distinguishing sexual behavior from sexual identity, communicating with gender-neutral terms, and maintaining awareness of how their own attitude affects clinical judgment. Scant research exists with regard to the best ways to teach medical students about the special challenge GBLT patients face. However, the recommendation is to integrate such teaching throughout the entire medical school curriculum. This article includes a summary of the medical literature for the GBLT patients' health care needs and suggests strategies for enhancing the care for this population, as well as incorporating it during the medical education.
Asunto(s)
Consultores , Relaciones Médico-Paciente , Conducta Sexual/psicología , Bisexualidad , Femenino , Identidad de Género , Homosexualidad Femenina/psicología , Homosexualidad Masculina/psicología , Humanos , Masculino , Médicos/psicologíaRESUMEN
PURPOSE: Current low back pain (LBP) clinical guidelines have helped to summarize the scientific evidence and research, but have failed to provide tools and guide family physicians (FPs). The purpose of this study is to identify barriers and facilitators for the implementation of LBP guidelines from family FPs' perspective. METHODS: A qualitative focus group study of FPs in the north of Israel. Purposeful sampling was used to recruit participants, all of them board-certified FPs. Four focus groups were created, and discussions were taped, transcribed and analysed for major themes. RESULTS: Focus groups findings have expanded the understanding of the intellectual and mental challenges faced by Israeli FPs caring for LBP patients and highlighted the many obstacles to implementing LBP guidelines. Physicians' decision-making, pertaining to LBP, functions on three levels simultaneously: the physicians' agenda based on familiarity with the guidelines; their need to remain grounded in the context of the specific patient-doctor relationship; and the constraints and demands of the physician's workplace, medical system and environment. CONCLUSIONS: Despite an overall positive attitude towards LBP guideline implementation, FPs found it hard to come to terms with the conflicting dimensions of LBP patient care. The patient-doctor interaction determined the outcome of the encounter, whether it complied with the guidelines and whether the encounter leads to a healing process or to a vicious circle of unnecessary utilization of services.
Asunto(s)
Dolor de la Región Lumbar/terapia , Médicos de Familia/normas , Guías de Práctica Clínica como Asunto , Adulto , Actitud del Personal de Salud , Toma de Decisiones , Femenino , Grupos Focales , Humanos , Masculino , Persona de Mediana Edad , Relaciones Médico-Paciente , Pautas de la Práctica en Medicina/normas , Investigación CualitativaRESUMEN
OBJECTIVE: To describe a new tool designed to capture patients' perception of their low back pain (LBP) episodes-the patient perception scale (PPS) and test its ability to predict episode outcomes. METHODS: Thirty-two family physicians recruited 526 low back pain patients during an office visit. Physicians completed a short questionnaire at the index visit, which included both their assessments of patients' patient perception scale (PPS-doc) and contact information. Patients were then interviewed by telephone within 2 weeks after the index visit, with follow-up telephone contacts at 2, 4, 8 and 12 months. The patient perception scale as reported by the physician (PPS-doc) and patient (PPS-pt), each constituent question, and different combinations were analyzed for their ability to predict patient outcomes. RESULTS: Patients' responses (PPS-pt) proved predictive for all outcome items. PPS-doc was much less predictive. Measures of patient centeredness did not perform well in this study. CONCLUSION: By using a short scale based on the patient's perception of pain (PPS-pt), it is possible to predict adverse outcomes of a low back pain episode. The patient perception scale should be evaluated further and perhaps combined with other instruments for targeting care and chronicity prevention efforts in low back pain. PRACTICE IMPLICATIONS: The PPS-pt could potentially be used as part of the standard initial patient evaluation of new LBP patients, as a proxy for "yellow flags" (markers of psychosocial risk) where a positive score might be the equivalent to high-risk identification. The apparent advantage of this scale is its brevity and simplicity of administration. The separation, through this scale of pain episodes into simple and complex LBP might be a useful tool for helping direct resources and avoiding chronicity.
Asunto(s)
Dolor de la Región Lumbar/diagnóstico , Dimensión del Dolor/métodos , Atención Dirigida al Paciente , Encuestas y Cuestionarios , Enfermedad Crónica , Medicina Familiar y Comunitaria , Femenino , Estudios de Seguimiento , Humanos , Israel , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Resultado del TratamientoRESUMEN
OBJECTIVE: Aggregation (i.e., meta-ethnography or meta-synthesis) of qualitative studies remains relatively rare and controversial. We have attempted this procedure within an investigation of patient priorities and evaluations of primary care in order to triangulate an instrument development process as well as explore associated dilemmas. METHODS: The procedures included a literature search of qualitative research on patient priorities and evaluations and creation of a framework for quality assessment of retrieved papers. The tool for the evaluation of quality in qualitative studies was piloted, refined, and applied to the retrieved literature. The articles were equally distributed between two teams in random fashion, and inter-rater agreement calculated. Finally, we formulated and applied a strategy for aggregation of data from included papers that allowed comparison to a systematic review of quantitative studies on the topic. RESULTS: Thirty-seven articles met inclusion criteria. Twenty-four of these articles were of sufficient quality to be included in the qualitative aggregation. Inter-rater agreement ranged from 0.22 to 0.77 and 0.38 to 0.60 for pair and assessor comparisons, respectively. The aggregation strategy enabled synthesis within sub-categories of the heterogeneous papers. CONCLUSIONS: We have devised a modestly reliable instrument to assess the quality of qualitative work. The procedure for quality assessment and aggregation appears to be both feasible and potentially useful, though both theoretical and practical problems underline the need for further refinement prior to widespread utilization of this approach. PRACTICE IMPLICATIONS: An instrument to assess the quality of qualitative work within the context of aggregation efforts is described. Calculating inter-rater reliability in this framework can support future quality assessments. A method of breaking a heterogeneous collection of included papers into sub-categories to enable aggregation of qualitative studies is applied and demonstrates its feasibility and potential usefulness.
Asunto(s)
Actitud Frente a la Salud , Medicina Familiar y Comunitaria , Investigación sobre Servicios de Salud , Atención Primaria de Salud , Investigación Cualitativa , Proyectos de Investigación/normas , Antropología Cultural , Comunicación , Recolección de Datos/métodos , Recolección de Datos/normas , Interpretación Estadística de Datos , Medicina Familiar y Comunitaria/normas , Conocimientos, Actitudes y Práctica en Salud , Prioridades en Salud , Necesidades y Demandas de Servicios de Salud , Investigación sobre Servicios de Salud/métodos , Investigación sobre Servicios de Salud/normas , Humanos , Variaciones Dependientes del Observador , Relaciones Médico-Paciente , Atención Primaria de Salud/normasRESUMEN
BACKGROUND: Israeli youth lead 27 western countries in dieting. The prevalence of eating disorders has been rising in the last 30 years, causing social problems and medical complications. OBJECTIVES: To examine the prevalence of eating disorders among high school students in a region in northern Israel (Misgav) and to examine the relationship between the parents' employment status and the subject's eating disorder. METHODS: A structured questionnaire was administered to collect demographic data. The short version of the Eating Attitudes Test (EAT-26) was used to evaluate the subject's attitudes toward and preoccupation with food, dieting, eating, physical appearance, and personal control over eating. RESULTS: Of 360 students approached, 283 (78%) completed the self-report EAT-26. One of every 5 females and one in every 20 males had an abnormal eating attitude. The rate of pathologic EAT-26 results, 20.8%, falls within the high range of similar community-based samples of female adolescents. There were no differences in EAT-26 score between students with an employed or unemployed mother; however, there was a trend for higher EAT-26 scores among those whose father was unemployed (21.4% vs. 12.7%, chi2 = 0.14). CONCLUSIONS: The findings support our hypothesis of a relatively high rate of abnormal eating attitudes (as reflected by high EAT-26 score) in this population. Another possible risk factor is having an unemployed father, which warrants further research and attention. Our next step is to introduce an intervention program in the school and to study its effect.
Asunto(s)
Conducta del Adolescente/psicología , Actitud Frente a la Salud , Conducta Alimentaria , Trastornos de Alimentación y de la Ingestión de Alimentos/epidemiología , Conductas Relacionadas con la Salud , Judíos/psicología , Estudiantes/psicología , Adolescente , Índice de Masa Corporal , Estudios Transversales , Trastornos de Alimentación y de la Ingestión de Alimentos/psicología , Femenino , Humanos , Israel/epidemiología , Masculino , Prevalencia , Medición de Riesgo , Encuestas y CuestionariosRESUMEN
BACKGROUND: Several studies have suggested that an early increase in renal nitric oxide (NO) production or activity mediates pathophysiologic and morphologic changes in diabetic nephropathy. To evaluate the role of NO in developing diabetic kidney disease, we studied the NO system in streptozotocin (STZ)-induced diabetic rats for a period of 8 weeks. METHODS: Control rats, STZ-induced diabetic rats, and STZ-induced diabetic rats treated with insulin were monitored and sacrificed at 1, 2, and 8 weeks. Urinary cGMP was measured, and the levels and activity of NO synthase (NOS) isoforms in the kidney cortex were determined at specific times by immunoblotting and diaphorase staining. RESULTS: Diabetic rats had increased kidney weight, urinary volume, glucose, sodium and potassium excretion, which was precluded by insulin treatment. Creatinine clearance was increased in the diabetic group and reversed by insulin treatment. Urinary cGMP decreased by 71, 93, and 92% at 1, 2, and 8 weeks of diabetes, respectively, compared with the control animals. Insulin treatment curtailed the urinary cGMP reduction in diabetic animals. Total NOS activity in the renal cortex was reduced by 65, 52, and 44% after 1, 2, and 8 weeks of diabetes, respectively, and returned to normal levels upon insulin treatment. NADPH diaphorase staining of renal cortical slices showed a 77, 63, and 70% decrease in neuronal NOS isoform activity in the macula densa after 1, 2, and 8 weeks of diabetes, respectively, compared with control non-diabetic animals. This reduction was normalized by insulin treatment. Endothelial NOS protein expression in the kidney cortex tended to increase after 1 week of diabetes and its level was elevated significantly after 2 and 8 weeks of diabetes. However, neuronal NOS protein expression in the kidney cortex was reduced by 52% in 2-week diabetic animals, but this reduction was normalized by insulin treatment. CONCLUSIONS: The decreased renal NOS activity during the late phase of diabetes is partially associated with a decrease in neuronal NOS activity and protein expression in kidney macula densa.
Asunto(s)
Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Experimental/metabolismo , Nefropatías Diabéticas/tratamiento farmacológico , Nefropatías Diabéticas/metabolismo , Insulina/uso terapéutico , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico/metabolismo , Animales , Enfermedad Crónica , Diabetes Mellitus Experimental/inducido químicamente , Nefropatías Diabéticas/inducido químicamente , Activación Enzimática/efectos de los fármacos , Corteza Renal/efectos de los fármacos , Corteza Renal/metabolismo , Masculino , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Ratas , Estreptozocina , Resultado del TratamientoRESUMEN
Smoking is one of the most preventable causes of morbidity and mortality resulting in almost 10,000 deaths each year in Israel. Since tobacco-related disease is preventable, efforts to promote cessation in patients who smoke should be a routine step in preventive primary care measures. In Israel, 26% of the adult population smoke. Within this group, a third want to quit but only two percent succeed in abstaining from smoking for a whole year. Family physicians are in an ideal position to facilitate patients' attempts to quit smoking: 70% of smoking patients report that firm, supportive messages from their family physician can act as an important motivating factor to quit smoking. The updated Clinical Practice Guidelines from the US Public Health Service recommend that family physicians should opportunistically advise smokers to stop smoking during routine consultation, encourage and assist smokers in the use of nicotine replacement therapies or bupropion and refer smokers to professional behavioral or psychological counselors specializing in smoking cessation. Most physicians rank smoking as the most important behavior affecting health, but few physicians are confident in their own ability to help their patients stop smoking. In this review the authors present several evidence-based strategies that were found to be helpful in promoting smoking cessation when delivered by general practitioners. The power of the physician's advice, first and second line agents, behavioral counseling and stage based interventions, are all discussed in detail.
Asunto(s)
Medicina Basada en la Evidencia , Cese del Hábito de Fumar , Humanos , Médicos de Familia , Fumar/efectos adversosRESUMEN
Endothelin-1 (ET-1) is both a potent vasoconstrictor and mitogenic factor that has been implicated as a cause of the micro- and macrovascular complications of diabetes mellitus. The pathway by which the high-glucose environment of diabetes mediates increased levels of endothelins has not been completely elucidated but appears to involve endothelin-converting enzyme (ECE-1), which converts inactive big ET-1 to active ET-1 peptide. To determine the effect of high glucose concentrations on the expression of ECE-1, hybrid endothelial cells (EA.hy926) and human umbilical vein endothelial cells (HUVEC) were both grown in various glucose concentrations. There was a 2-fold increase in ECE-1 immunoreactivity in the EA.hy926 cell line growing in medium containing 22.2 versus 5.5 mmol/l glucose after 24 h, which rose to greater than 20-fold after 5 days. Similar results were seen with HUVEC. Bradykinin or NG-nitro-L-arginine methyl ester did not change the effect of high glucose on ECE-1 protein expression. High glucose induced a 72 and 41% increase in total protein kinase C (PKC) activity in both EA.hy926 cells and HUVEC, respectively, and a 39, 49 and 109% elevation in PKC beta1, beta2 and delta expression, respectively, in EA.hy926 cells. The increase in ECE-1 expression was inhibited in both cell cultures by GF109203X (5 micromol/l), a general PKC inhibitor, while addition of 10 nmol/l phorbol myristic acid to EA.hy926 cells or HUVEC growing on medium containing 5.5 mmol/l glucose increased ECE-1 expression to a level similar to that of cells conditioned in high glucose. Human ECE-1 protein exists in four different isoforms, termed 1a, 1b, 1c and 1d. Northern blot analysis revealed that only ECE-1c isoform mRNA levels increased. Immunohistochemical staining of EA.hy926 cells grown in high glucose concentrations demonstrated an increase in the ECE-1c isoform, which occurred mainly in the plasma membrane. These results showed that the PKC pathway may play an important role in the glucose-mediated induction of ECE-1 expression. The main isoform to increase in response to high glucose was ECE-1c. This enzyme may be one of the factors contributing to the elevated ET-1 peptide levels observed in diabetes.
Asunto(s)
Ácido Aspártico Endopeptidasas/genética , Ácido Aspártico Endopeptidasas/metabolismo , Células Epiteliales/metabolismo , Glucosa/farmacología , Isoenzimas/genética , Isoenzimas/metabolismo , Células Cultivadas , Nefropatías Diabéticas/metabolismo , Nefropatías Diabéticas/fisiopatología , Enzimas Convertidoras de Endotelina , Endotelio Vascular/citología , Células Epiteliales/citología , Células Epiteliales/efectos de los fármacos , Regulación Enzimológica de la Expresión Génica , Humanos , Pulmón/citología , Metaloendopeptidasas , Óxido Nítrico/metabolismo , Proteína Quinasa C/metabolismo , ARN Mensajero/análisis , Venas Umbilicales/citologíaRESUMEN
Pregnancy-induced hypertension in rats with chronic exogenous hyperinsulinemia is associated with reduced urinary excretion of nitric oxide metabolites. We tested the hypothesis that there are perturbations of endothelial nitric oxide synthase in their kidneys. We studied three groups of rats: control pregnant rats (n = 6); pregnant rats with hyperinsulinemia by subcutaneous sustained-release insulin pellet (n = 5); and hyperinsulinemic pregnant rats treated with l-arginine 2 gL in drinking water (n = 5). By the end of pregnancy blood pressure was 78 +/- 12 mm Hg in controls, 119 +/- 15 mm Hg in hyperinsulinemic rats, and 77 +/- 8 mm Hg in l-arginine-treated hyperinsulinemic rats, p < 0.007. Serum creatinine was 0.4 mg/dl in controls, 0.6 mg/dl in hyperinsulinemic rats, and 0.5 mg/dl in l-arginine-treated rats, p < 0.05. Corresponding urinary excretion of nitric oxide metabolites was 2.1 +/- 0.5, 1.2 +/- 0.2, and 1.5 +/- 0.2 micromols/mg creatinine, p < 0.01. Expression of endothelial nitric oxide synthase protein in kidneys by Western blot was not different between controls and hyperinsulinemic rats, 5.6 +/- 2.4 and 5.8 +/- 3.4 OD x mm2, but was nearly doubled in l-arginine-treated rats, 10.8 +/- 2.3, p < 0.03. Thus, the salutary effect of l-arginine on hyperinsulinemic pregnancy-induced hypertension (PIH) may be mediated, in part, by endothelial nitric oxide synthase in their kidneys.