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OBJECTIVE: Functioning gonadotroph adenomas (FGAs) are rare pituitary tumours stimulating ovarian function with potential life-threatening consequences in women. However, a lack of aggregated clinical experience of FGAs impairs management in affected women. The aim of this study is to present the clinical course of FGA-induced ovarian hyperstimulation syndrome (OHSS) cases as identified by some of the largest UK pituitary endocrine tertiary centres with a view to increasing awareness and improving diagnosis and management of women with FGA. DESIGN: A retrospective observational study; audit of eight UK regional pituitary centres for cases of FGAs. SETTING: Specialist neuroendocrine centres in the United Kingdom. PATIENTS AND MEASUREMENTS: Women diagnosed with FGA-induced OHSS. Description of their clinical course. RESULTS: Seven cases of FGA were identified in women, all causing OHSS. Mean age was 33.4 years at diagnosis. Abdominal pain, irregular periods, headache, and visual disturbances were reported at presentation by 100%, 71%, 57% and 43% of women, respectively. Three of seven women underwent ovarian surgery before FGA diagnosis. Six women underwent transsphenoidal surgery (TSS) with incomplete tumour resection in five of those, but all showed improvement or resolution in symptoms and biochemistry postoperatively. CONCLUSION: FGA is a rare cause of spontaneous OHSS. TSS improves clinical and biochemical features of ovarian hyperstimulation in FGAs. Improved awareness of FGA will prevent inappropriate emergency ovarian surgery.
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Adenoma , Gonadotrofos , Síndrome de Hiperestimulación Ovárica , Neoplasias Hipofisarias , Femenino , Humanos , Adulto , Neoplasias Hipofisarias/cirugía , Síndrome de Hiperestimulación Ovárica/etiología , Adenoma/patología , Progresión de la EnfermedadRESUMEN
CONTEXT: Prednisolone has been recommended rather than hydrocortisone for glucocorticoid replacement in adrenal insufficiency due its longer duration of action and lower cost. OBJECTIVE: To determine mortality rates with prednisolone versus hydrocortisone. METHODS: In this observational study, we used data extracted from a UK primary care database (Clinical Practice Research Datalink) to measure the relative mortality of patients with primary and secondary adrenal insufficiency, who were treated with either prednisolone or hydrocortisone, and control individuals who were individually matched for age, sex, period, and place of follow-up. RESULTS: As expected, mortality in adrenal insufficiency irrespective of cause was increased, based on 5478 patients (4228 on hydrocortisone; 1250 on prednisolone) and 54 314 controls (41 934 and 12 380, respectively). Overall, the adjusted hazard ratio (HR) was similar with the 2 treatments (prednisolone, 1.76 [95% CI, 1.54-2.01] vs hydrocortisone 1.69 [1.57-1.82]; P = 0.65). This was also the case for secondary adrenal insufficiency. In primary disease (1405 on hydrocortisone vs 137 on prednisolone; 13 965 and 1347 controls, respectively), prednisolone users were older, more likely to have another autoimmune disease and malignancy, and less likely to have mineralocorticoid replacement. Nevertheless, after adjustment, the HR for prednisolone-treated patients remained higher than for those taking hydrocortisone (2.92 [2.19-3.91] vs 1.90 [1.66-2.16]; P = 0.0020). CONCLUSION: In primary but not in secondary adrenal insufficiency, mortality was higher with prednisolone. The study was large, but the number of prednisolone-treated patients was small, and they had greater risk factors. Nonetheless, the increased mortality associated with prednisolone persisted despite statistical adjustment. Further evidence is needed regarding the long-term safety of prednisolone as routine replacement.
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Insuficiencia Suprarrenal/tratamiento farmacológico , Insuficiencia Suprarrenal/mortalidad , Glucocorticoides/efectos adversos , Terapia de Reemplazo de Hormonas/efectos adversos , Hidrocortisona/efectos adversos , Prednisolona/efectos adversos , Adulto , Anciano , Femenino , Glucocorticoides/uso terapéutico , Humanos , Hidrocortisona/uso terapéutico , Masculino , Persona de Mediana Edad , Prednisolona/uso terapéutico , Estudios Retrospectivos , Tasa de SupervivenciaRESUMEN
CONTEXT: Mortality studies have established that cardiovascular disease is the leading cause of death in patients with adrenal insufficiency and the risk is greater than that observed in individually matched controls. OBJECTIVE: Here we have performed a detailed analysis of cardiovascular morbidity and mortality, taking account of the role of comorbidities. METHODS: We performed a retrospective cohort study using the Clinical Practice Research Datalink (CPRD), a UK general practitioner database. The participant population comprised 6821 patients with adrenal insufficiency (primary, 2052; secondary, 3948) compared with 67 564 individually matched controls, with and without adjustment for comorbidities (diabetes, hypertension, dyslipidemia, previous cardiovascular disease, and smoking). The main outcome measures were composite cardiovascular events recorded in the CPRD and cardiovascular mortality in participants with linked national mortality data. RESULTS: Hazard ratios (95% CI) for composite cardiovascular events in patients with adrenal insufficiency of any cause were 1.28 (1.20-1.36, unadjusted) and 1.07 (1.01-1.14, adjusted). Increased cerebrovascular events in patients with secondary adrenal insufficiency accounted for most of the increased hazard (1.53 [1.34-1.74, adjusted]) and were associated with cranial irradiation therapy. Cardiovascular mortality data were available for 3547 patients and 34 944 controls. The adjusted hazard ratio for ischemic heart disease mortality was 1.86 (1.25-2.78) for primary adrenal insufficiency and 1.39 (1.02-1.89) for secondary. CONCLUSION: Comorbidities largely accounted for the increased cardiovascular events but in secondary adrenal insufficiency, cerebrovascular events were independently increased and associated with irradiation treatment. However, the risk of cardiovascular mortality remained increased even following adjustment for comorbidities in both primary and secondary adrenal insufficiency.
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Enfermedad de Addison/epidemiología , Insuficiencia Suprarrenal/epidemiología , Enfermedades Cardiovasculares/epidemiología , Enfermedad de Addison/complicaciones , Insuficiencia Suprarrenal/etiología , Adulto , Anciano , Enfermedades Cardiovasculares/etiología , Estudios de Casos y Controles , Estudios de Cohortes , Comorbilidad , Femenino , Medicina General/estadística & datos numéricos , Humanos , Hipertensión/epidemiología , Hipertensión/etiología , Incidencia , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Reino Unido/epidemiologíaRESUMEN
CONTEXT: Mortality data in patients with adrenal insufficiency are inconsistent, possibly due to temporal and geographical differences between patients and their reference populations. OBJECTIVE: To compare mortality risk and causes of death in adrenal insufficiency with an individually matched reference population. METHODS: A retrospective cohort study was done using a UK general practitioner database (CPRD). A total of 6821 patients with adrenal insufficiency (primary, 2052; secondary, 3948) were compared with 67564 individually-matched controls (primary, 20366; secondary, 39134). Main outcomes were all-cause and cause-specific mortality, and hospital admission from adrenal crisis. RESULTS: With follow-up of 40 799 and 406 899 person-years for patients and controls respectively, the hazard ratio (HR [95% CI]) for all-cause mortality was 1.68 [1.58-1.77]. HRs were greater in primary (1.83 [1.66-2.02]) than in secondary (1.52 [1.40-1.64]) disease; primary versus secondary disease (1.16 [1.03-1.30]). The leading cause of death was cardiovascular disease (HR 1.54 [1.32-1.80]), along with malignant neoplasms and respiratory disease. Deaths from infection were also relatively high (HR 4.00 [2.15-7.46]). Adrenal crisis contributed to 10% of all deaths. In the first 2 years following diagnosis, the patients' mortality rate and hospitalization from adrenal crisis were higher than in later years. CONCLUSION: Mortality was increased in adrenal insufficiency, especially primary, even with individual matching and was observed early in the disease course. Cardiovascular disease was the major cause but mortality from infection was also high. Adrenal crisis was a common contributor. Early education for prompt treatment of infections and avoidance of adrenal crisis hold potential to reduce mortality.
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Insuficiencia Suprarrenal/mortalidad , Enfermedad Aguda , Insuficiencia Suprarrenal/etiología , Adulto , Anciano , Enfermedades Cardiovasculares/complicaciones , Enfermedades Cardiovasculares/mortalidad , Causas de Muerte , Bases de Datos Factuales , Femenino , Medicina General/estadística & datos numéricos , Hospitalización/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Riesgo , Reino Unido/epidemiologíaRESUMEN
BACKGROUND: Revision parathyroid is challenging due to possible diagnostic uncertainty as well as the technical challenges it can present. METHODS: A multidisciplinary panel of distinguished experts from the American Head and Neck Society (AHNS) Endocrine Section, the British Association of Endocrine and Thyroid Surgeons (BAETS), and other invited experts have reviewed this topic with the purpose of making recommendations based on current best evidence. The literature was also reviewed on May 12, 2017. PubMed (1946-2017), Cochrane SR (2005-2017), CT databases (1997-2017), and Web of Science (1945-2017) were searched with the following strategy: revision and reoperative parathyroidectomy to ensure completeness. RESULTS: Guideline recommendations were made in 3 domains: preoperative evaluation, surgical management, and alternatives to surgery. Eleven guideline recommendations are proposed. CONCLUSION: Reoperative parathyroid surgery is best avoided if possible. Our literature search and subsequent recommendations found that these cases are best managed by experienced surgeons using precision preoperative localization, intraoperative parathyroid hormone (PTH), and the team approach.
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Hiperparatiroidismo Primario/cirugía , Glándulas Paratiroides/cirugía , Paratiroidectomía , Reoperación , Densidad Ósea , Calcio/sangre , Colecalciferol/uso terapéutico , Competencia Clínica , Diagnóstico Diferencial , Hospitales de Alto Volumen , Humanos , Hiperparatiroidismo Primario/diagnóstico , Monitorización Neurofisiológica Intraoperatoria , Anamnesis , Glándulas Paratiroides/diagnóstico por imagen , Selección de Paciente , Complicaciones Posoperatorias/prevención & control , Cuidados Preoperatorios , Recurrencia , Sociedades Médicas , Deficiencia de Vitamina D/tratamiento farmacológico , Vitaminas/uso terapéuticoRESUMEN
BACKGROUND: Metagenomics is a rapidly emerging field aimed to analyze microbial diversity and dynamics by studying the genomic content of the microbiota. Metataxonomics tools analyze high-throughput sequencing data, primarily from 16S rRNA gene sequencing and DNAseq, to identify microorganisms and viruses within a complex mixture. With the growing demand for analysis of the functional microbiome, metatranscriptome studies attract more interest. To make metatranscriptomic data sufficient for metataxonomics, new analytical workflows are needed to deal with sparse and taxonomically less informative sequencing data. RESULTS: We present a new protocol, IMSA+A, for accurate taxonomy classification based on metatranscriptome data of any read length that can efficiently and robustly identify bacteria, fungi, and viruses in the same sample. The new protocol improves accuracy by using a conservative reference database, employing a new counting scheme, and by assembling shotgun reads. Assembly also reduces analysis runtime. Simulated data were utilized to evaluate the protocol by permuting common experimental variables. When applied to the real metatranscriptome data for mouse intestines colonized by ASF, the protocol showed superior performance in detection of the microorganisms compared to the existing metataxonomics tools. IMSA+A is available at https://github.com/JeremyCoxBMI/IMSA-A . CONCLUSIONS: The developed protocol addresses the need for taxonomy classification from RNAseq data. Previously not utilized, i.e., unmapped to a reference genome, RNAseq reads can now be used to gather taxonomic information about the microbiota present in a biological sample without conducting additional sequencing. Any metatranscriptome pipeline that includes assembly of reads can add this analysis with minimal additional cost of compute time. The new protocol also creates an opportunity to revisit old metatranscriptome data, where taxonomic content may be important but was not analyzed.
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Bacterias/clasificación , Hongos/clasificación , Metagenómica/métodos , Microbiota/genética , Virus/clasificación , Algoritmos , Animales , Bacterias/genética , Secuencia de Bases , Bases de Datos Genéticas , Hongos/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Ratones , ARN Ribosómico 16S/genética , Análisis de Secuencia de ARN , Virus/genéticaRESUMEN
CONTEXT: Existing data regarding the association between growth hormone deficiency (GHD) and liver fat content are conflicting. OBJECTIVE: We aimed (i) to assess intrahepatocellular lipid (IHCL) content in hypopituitary adults with GHD compared to matched controls and (ii) to evaluate the effect of growth hormone (GH) replacement on IHCL content. DESIGN: Cross-sectional comparison and controlled intervention study. PATIENTS, PARTICIPANTS: Cross-sectional comparison: Twenty-two hypopituitary adults with GHD and 44 healthy controls matched for age, BMI, gender and ethnicity. Intervention study: nine GHD patients starting GH replacement (GH Rx group) and nine GHD patients not starting replacement therapy (non-GH Rx group). INTERVENTION: Intervention study: GH replacement for 6 months in the GH Rx group, dosage was titrated to achieve normal IGF-1 levels. MAIN OUTCOME MEASURES: HCL content determined by proton magnetic resonance spectroscopy ((1) H MRS). RESULTS: Cross-sectional Comparison: There was no difference in IHCL content between GHD patients and healthy controls (1·89% (0·30, 4·03) vs 1·14% (0·22, 2·32); P = 0·2), and the prevalence of patients with hepatic steatosis (IHCL of ≥ 5·56%) was similar in the two groups (22·7% vs 15·9%; chi-square probability = 0·4). Intervention study: The change in IHCL content over 6 months did not differ between the GH Rx group and the non-GH Rx group (-0·63 ± 4·53% vs + 0·11 ± 1·46%; P = 0·6). CONCLUSIONS: In our study, liver fat content and the prevalence of hepatic steatosis did not differ between hypopituitary adults with GHD and matched controls. In GHD patients, GH replacement had no effect on liver fat content.
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Hormona del Crecimiento/deficiencia , Hígado/patología , Adulto , Anciano , Estudios de Casos y Controles , Estudios Transversales , Hígado Graso , Femenino , Hormona del Crecimiento/uso terapéutico , Terapia de Reemplazo de Hormonas/métodos , Humanos , Hipopituitarismo , Resistencia a la Insulina , Grasa Intraabdominal , Imagen por Resonancia Magnética , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: Targeted parathyroidectomy is a popular technique for localized pathology. No single technique is established as superior. The purpose of this study was to compare robotic-assisted parathyroidectomy (RAP) with the most common approach. METHODS: This was a prospective, nonrandomized study. Fifteen consecutive patients who underwent RAP were compared to 15 matched controls undergoing focused lateral parathyroidectomy (FLP). RESULTS: Biochemical cure occurred in 29 of 30 patients (97%). No major complications occurred, although there was 1 robotic conversion. RAP demonstrated a significant time reduction (R(2) = 0.436; p = .01) but took much longer to perform than FLP (119 minutes vs 34 minutes; p = .001). RAP was associated with less initial postoperative pain (p = .036) and higher satisfaction with scar cosmesis (p = .002) until 6 months. Quality of life (QOL) improved in both groups (p = .007). CONCLUSION: RAP provides superior early cosmesis with equivalent global health improvement compared to FLP. The high cost and learning curve may preclude widespread adoption. Further evaluation is necessary to establish its clinical efficacy regarding scar cosmesis. © 2015 Wiley Periodicals, Inc. Head Neck 38: E300-E7, 2016.
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Hiperparatiroidismo Primario/cirugía , Procedimientos Quirúrgicos Mínimamente Invasivos , Paratiroidectomía/métodos , Procedimientos Quirúrgicos Robotizados , Adulto , Anciano , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Calidad de VidaRESUMEN
CONTEXT: The natural history and the optimum management of patients with nonfunctioning pituitary adenomas (NFPAs) are unclear. OBJECTIVE: Our objective was to characterize the natural history of patients with NFPAs managed conservatively. DESIGN AND PATIENTS: We conducted a retrospective analysis of patients presenting to a tertiary referral centre between 1986 and 2009. Patients with pituitary adenomas and no clinical or biochemical evidence of hormonal hypersecretion were included. Those presenting with apoplexy or a radiological follow-up period of less than 1 year were excluded. The pituitary imaging for all patients was re-examined by two neuroradiologists in consensus. OUTCOME MEASURES: The outcome measures were change in tumour size and pituitary hormone function. RESULTS: Sixty-six patients were managed conservatively for a mean follow-up period of 4·3 years (range: 1-14·7). Forty-seven (71%) had a macroadenoma, and nineteen (29%) had a microadenoma. Tumour size decreased or remained stable in 40% of macroadenomas and 47% of microadenomas. The median annual growth rate of enlarging macroadenomas and microadenomas was 1·0 mm/year and 0·4 mm/year, respectively. The median annual growth rate of macroadenomas was significantly higher than that of microadenomas (P < 0·01). Sixty-eight percentage of patients with a macroadenoma had pituitary hormone deficiency in one or more axes, compared to 42% of those with a microadenoma. CONCLUSION: Patients with NFPAs without optic chiasm compression can be managed conservatively. All patients need pituitary function assessment, irrespective of tumour size. These findings provide clinically relevant data for the management of patients with NFPAs.
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Adenoma/patología , Neoplasias Hipofisarias/patología , Adulto , Femenino , Humanos , Masculino , Hipófisis/patología , Estudios Retrospectivos , Espera VigilanteRESUMEN
OBJECTIVE: Targeted parathyroidectomy is the gold standard for localized parathyroid disease. A robotic-assisted approach has not been investigated. The aim was to assess the feasibility of a robotic technique that avoids a neck scar. STUDY DESIGN: Feasibility study. SETTING: Tertiary referral center. SUBJECTS AND METHODS: Eleven patients with primary hyperparathyroidism were prospectively evaluated. Triple modality concordant localization was a prerequisite. All patients underwent robotic-assisted parathyroidectomy (RAP). Outcome variables assessed were operative time, voice change, biochemical cure, and histopathological confirmation. Patient-reported outcome measures (PROMs) included subjective assessment of pain and scar cosmesis, Voice Handicap Index 2, and EQ-5D quality-of-life assessment. Mean follow-up was 6 months (range, 3-12 months). RESULTS: The parathyroid adenoma was successfully excised in all cases with negligible blood loss (<5 mL). There was 1 conversion. There was no voice change in any case. Robot docking time plateaued to 10 minutes after 8 cases. Mean exposure and console times (31 and 51 minutes, respectively) were affected by body habitus. The mean visual analog scale for scar cosmesis was 75% on the first postoperative day, improving to 92% at 6 months and 95% at 1 year. Pain scores decreased to 8% at 2 weeks. All 5 EQ-5D quality-of-life parameters significantly improved following surgery. CONCLUSION: The robotic approach is feasible for performing targeted parathyroidectomy that avoids a neck scar. The clinical efficacy and cost-effectiveness of the robotic approach compared with conventional targeted parathyroidectomy warrant further evaluation to establish if this represents a viable alternative to the existing targeted techniques.
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Hiperparatiroidismo Primario/cirugía , Hormona Paratiroidea/sangre , Neoplasias de las Paratiroides/cirugía , Paratiroidectomía/métodos , Robótica/instrumentación , Anciano , Diseño de Equipo , Estudios de Factibilidad , Femenino , Estudios de Seguimiento , Humanos , Hiperparatiroidismo Primario/sangre , Hiperparatiroidismo Primario/diagnóstico , Masculino , Persona de Mediana Edad , Neoplasias de las Paratiroides/sangre , Neoplasias de las Paratiroides/diagnóstico , Proyectos Piloto , Estudios Prospectivos , Tomografía Computarizada de Emisión de Fotón Único , Resultado del TratamientoRESUMEN
We sought to determine whether sex differences exist for the cannabinoid modulation of appetite, body temperature and neurotransmission at pro-opiomelanocortin (POMC) synapses. Gonadectomized male and female guinea pigs were outfitted to monitor core body temperature and injected with either the CB1 receptor agonist WIN 55,212-2 (1 mg/kg s.c.), antagonist AM251 (3 mg/kg s.c.) or vehicle (1 ml/kg s.c.) and evaluated for changes in six indices of feeding behavior under ad libitum conditions for 7 days. WIN 55,212-2 elicited an overt, sexually differentiated hyperphagia in which males displayed larger increases in hourly and daily intake, consumption/gram body weight, meal size and meal duration. The agonist also produced a more robust acute hypothermia in males than in females. In addition, males were more sensitive to the hypophagic effect of AM251, manifested by comparatively sizeable decreases in hourly intake, consumption/gram body weight, meal frequency and hyperthermia. To gain additional insight into the cellular mechanism underlying cannabinoid regulation of energy homeostasis, we performed whole-cell patch clamp recordings in hypothalamic slices prepared from gonadectomized male and female guinea pigs, and monitored miniature excitatory and inhibitory postsynaptic currents (mEPSCs and mIPSCs) in arcuate (ARC) neurons. ARC neurons from females exhibited a higher basal mEPSC frequency. WIN 55,212-2 dose-dependently reduced mEPSC and mIPSC frequency; however, cells from males were far less sensitive to the CB1 receptor-mediated decrease in mIPSC frequency. These effects were observed in neurons subsequently identified as POMC neurons. These data reveal pronounced sex differences in how cannabinoids influence the hypothalamic control of homeostasis.
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Apetito/fisiología , Temperatura Corporal/fisiología , Cannabinoides/farmacología , Proopiomelanocortina/fisiología , Caracteres Sexuales , Sinapsis/fisiología , Animales , Apetito/efectos de los fármacos , Temperatura Corporal/efectos de los fármacos , Femenino , Cobayas , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptor Cannabinoide CB1/agonistas , Receptor Cannabinoide CB1/antagonistas & inhibidores , Receptor Cannabinoide CB1/deficiencia , Sinapsis/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Transmisión Sináptica/fisiologíaRESUMEN
INTRODUCTION: The purpose of this study was to examine the normal pituitary gland in male subjects with ultrashort echo time (TE) pulse sequences, describe its appearance and measure its signal intensity before and after contrast enhancement. METHODS: Eleven male volunteers (mean age 57.1 years; range 36-81 years) were examined with a fat-suppressed ultrashort TE (=0.08 ms) pulse sequence. The studies were repeated after the administration of intravenous gadodiamide. The MR scans were examined for gland morphology and signal intensity before and after enhancement. Endocrinological evaluation included baseline pituitary function tests and a glucagon stimulatory test to assess pituitary cortisol and growth hormone reserve. RESULTS: High signal intensity was observed in the anterior pituitary relative to the brain in nine of the 11 subjects. These regions involved the whole of the anterior pituitary in three subjects, were localised to one side in two examples and were seen inferiorly in three subjects. Signal intensities relative to the brain increased with age, with a peak around the sixth or seventh decade and decreasing thereafter. Overall, the pituitary function tests were considered to be within normal limits and did not correlate with pituitary gland signal intensity. CONCLUSION: The anterior pituitary shows increased signal intensity in normal subjects when examined with T(1)-weighted ultrashort TE pulse sequences. The cause of this increased intensity is unknown, but fibrosis and iron deposition are possible candidates. The variation in signal intensity with age followed the temporal pattern of iron content observed at post mortem. No relationship with endocrine status was observed.
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Imagen por Resonancia Magnética/métodos , Hipófisis/anatomía & histología , Adulto , Anciano , Anciano de 80 o más Años , Medios de Contraste , Gadolinio DTPA , Humanos , Masculino , Persona de Mediana EdadRESUMEN
We tested the hypothesis that cannabinoids modulate feeding in male guinea pigs, and correlated cannabinoid-induced changes in feeding behavior with alterations in glutamatergic synaptic currents impinging upon proopiomelanocortin (POMC) neurons of the hypothalamic arcuate nucleus. Feeding experiments were performed as follows: after a three-day acclimation period, animals were weighed and injected with either the CB1 receptor agonist WIN 55,212-2 (1 mg/kg, s.c.), antagonist AM251 (3 mg/kg, s.c.) or their cremophore/ethanol/saline vehicle (1:1:18; 1 ml/kg, s.c.) each day for seven days. WIN 55,212-2 increased, whereas AM251 decreased, the rate of cumulative food intake. The agonist effect was manifest primarily by increases in meal frequency and the amount of food eaten per meal. By contrast, the antagonist effect was associated with decreases in meal frequency, duration and weight loss. For the electrophysiological experiments, we performed whole-cell patch-clamp recordings from POMC neurons in hypothalamic slices. WIN 55,212-2 decreased the amplitude of evoked, glutamatergic excitatory postsynaptic currents (eEPSCs) and increased the S2:S1 ratio. Conversely, AM251 increased eEPSC amplitude per se, and blocked the inhibitory effects of the agonist. WIN 55,212-2 also decreased miniature EPSC (mEPSC) frequency; whereas AM251 increased mEPSC frequency per se, and again blocked the inhibitory effect of the agonist. A subpopulation of cells exhibited an agonist-induced outward current, which was blocked by AM251, associated with increased conductance and reversed polarity near the Nernst equilibrium potential for K(+). These data demonstrate that cannabinoids regulate appetite in the guinea pig in part through both presynaptic and postsynaptic actions on anorexigenic POMC neurons.
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Cannabinoides/farmacología , Hiperfagia/inducido químicamente , Hiperfagia/patología , Inhibición Neural/fisiología , Neuronas/efectos de los fármacos , Proopiomelanocortina/metabolismo , Analgésicos/farmacología , Análisis de Varianza , Animales , Conducta Animal/efectos de los fármacos , Benzoxazinas/farmacología , Peso Corporal/efectos de los fármacos , Cannabinoides/agonistas , Cannabinoides/antagonistas & inhibidores , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Ingestión de Alimentos/efectos de los fármacos , Antagonistas de Aminoácidos Excitadores/farmacología , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Potenciales Postsinápticos Excitadores/fisiología , GABAérgicos/farmacología , Cobayas , Hipotálamo/citología , Técnicas In Vitro , Masculino , Morfolinas/farmacología , Naftalenos/farmacología , Inhibición Neural/efectos de los fármacos , Piperidinas/farmacología , Pirazoles/farmacología , Estadística como AsuntoRESUMEN
Dent's disease is an X-linked renal tubular disorder characterized by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and renal failure. The disease is caused by mutations in a renal chloride channel gene, CLCN5, which encodes a 746 amino acid protein (CLC-5), with 12 to 13 transmembrane domains. In this study, an additional six unrelated patients with Dent's disease were identified and investigated for CLCN5 mutations by DNA sequence analysis of the 11 coding exons of CLCN5. This revealed six mutations: four frameshift deletions involving codons 392, 394, 658, and 728, one nonsense mutation (Tyr617Stop), and an A to T transversion at codon 601 that would result in either a missense mutation (Asp601Val) or creation of a novel donor splice site. These mutations were confirmed by restriction endonuclease or sequence-specific oligonucleotide hybridization analysis and were not common polymorphisms. The frameshift deletions and nonsense mutation predict truncated and inactivated CLC-5. The effects of the putative missense Asp601Val mutant CLC-5 were assessed by heterologous expression in Xenopus oocytes, and this revealed a chloride conductance that was similar to that observed for wild-type CLC-5. However, an analysis of the mutant CLCN5 transcripts revealed utilization of the novel donor splice site, resulting in a truncated CLC-5. Thus, all of the six mutations are likely to result in truncated CLC-5 and a loss of function, and these findings expand the spectrum of CLCN5 mutations associated with Dent's disease.