Unraveling Electron Dynamics in p-type Indium Phosphide (100): A Time-Resolved Two-Photon Photoemission Study.

Renewable ("green") hydrogen production through direct photoelectrochemical (PEC) water splitting is a potential key contributor to the sustainable energy mix of the future. We investigate the potential of indium phosphide (InP) as a reference material among III-V semiconductors for PEC and photovoltaic (PV) applications. The p(2 × 2)/c(4 × 2)-reconstructed phosphorus-terminated p-doped InP(100) (P-rich p-InP) surface is the focus of our investigation. We employ time-resolved two-photon photoemission (tr-2PPE) spectroscopy to study electronic states near the band gap with an emphasis on normally unoccupied conduction band states that are inaccessible through conventional single-photon emission methods. The study shows the complexity of the p-InP electronic band structure and reveals the presence of at least nine distinct states between the valence band edge and vacuum energy, including a valence band state, a surface defect state pinning the Fermi level, six unoccupied surface resonances within the conduction band, as well as a cluster of states about 1.6 eV above the CBM, identified as a bulk-to-surface transition. Furthermore, we determined the decay constants of five of the conduction band states, enabling us to track electron relaxation through the bulk and surface conduction bands. This comprehensive understanding of the electron dynamics in p-InP(100) lays the foundation for further exploration and surface engineering to enhance the properties and applications of p-InP-based III-V-compounds for, e.g., efficient and cost-effective PEC hydrogen production and highly efficient PV cells.

Regulation of metabolic health by dietary histidine in mice.

Low-protein (LP) diets are associated with a decreased risk of diabetes in humans, and promote leanness and glycaemic control in both rodents and humans. While the effects of an LP diet on glycaemic control are mediated by reduced levels of the branched-chain amino acids, we have observed that reducing dietary levels of the other six essential amino acids leads to changes in body composition. Here, we find that dietary histidine plays a key role in the response to an LP diet in male C57BL/6J mice. Specifically reducing dietary levels of histidine by 67% reduces the weight gain of young, lean male mice, reducing both adipose and lean mass without altering glucose metabolism, and rapidly reverses diet-induced obesity and hepatic steatosis in diet-induced obese male mice, increasing insulin sensitivity. This normalization of metabolic health was associated not with caloric restriction or increased activity, but with increased energy expenditure. Surprisingly, the effects of histidine restriction do not require the energy balance hormone Fgf21. Histidine restriction that was started in midlife promoted leanness and glucose tolerance in aged males but not females, but did not affect frailty or lifespan in either sex. Finally, we demonstrate that variation in dietary histidine levels helps to explain body mass index differences in humans. Overall, our findings demonstrate that dietary histidine is a key regulator of weight and body composition in male mice and in humans, and suggest that reducing dietary histidine may be a translatable option for the treatment of obesity. KEY POINTS: Protein restriction (PR) promotes metabolic health in rodents and humans and extends rodent lifespan. Restriction of specific individual essential amino acids can recapitulate the benefits of PR. Reduced histidine promotes leanness and increased energy expenditure in male mice. Reduced histidine does not extend the lifespan of mice when begun in midlife. Dietary levels of histidine are positively associated with body mass index in humans.

The Effect of Diet-induced Obesity on Toxicological Parameters in the Polygenic Sprague-Dawley Rat Model.

The obese rodent serves as an indispensable tool for proof-of-concept efficacy and mode-of-action pharmacology studies. Yet the utility of this disease model as an adjunct to the conventional healthy animal in the nonclinical safety evaluation of anti-obesity pharmacotherapies has not been elucidated. Regulatory authorities have recommended employing disease models in toxicology studies when necessary. Our study investigated standard and exploratory toxicology parameters in the high-fat diet (HFD)-induced obese, polygenic Sprague-Dawley rat model in comparison to chow diet (CD)-fed controls. We sought to establish feasibility of the model for safety testing and relevance to human obesity pathophysiology. We report that both sexes fed a 45% kcal HFD for 29 weeks developed obesity and metabolic derangements that mimics to a certain extent, common human obesity. Minor clinical pathologies were observed in both sexes and considered related to CD versus HFD differences. Histopathologically, both sexes exhibited mild obesity-associated findings in brown and subcutaneous white fat, bone, kidneys, liver, lung, pancreas, salivary parotid glands, and skeletal muscle. We conclude that chronic HFD feeding in both sexes led to the development of an obese but otherwise healthy rat. Therefore, the diet-induced obese Sprague-Dawley rat may serve as a suitable model for evaluating toxicity findings encountered with anti-obesity compounds.

The Parent Cyclopentadienyltin Cation, Its Toluene Adduct, and the Quadruple-Decker [Sn3 Cp4 ]2.

Truly cationic metallocenes with the parent cyclopentadienyl ligand are so far unknown for the Group 14 elements. Herein we report on an almost "naked" [SnCp]+ cation with the weakly coordinating [Al{OC(CF3 )3 }4 ]- and [{(F3 C)3 CO}3 Al-F-Al{OC(CF3 )3 }3 ]- anions. [SnCp][Al{OC(CF3 )3 }4 ] was used to prepare the first main-group quadruple-decker cation [Sn3 Cp4 ]2+ again as the [Al{OC(CF3 )3 }4 ]- salt. Additionally, the toluene adduct [CpSn(C7 H8 )][Al{OC(CF3 )3 }4 ] was obtained.

Central nervous system neuropeptide Y signaling via the Y1 receptor partially dissociates feeding behavior from lipoprotein metabolism in lean rats.

Elevated plasma triglyceride (TG) levels contribute to an atherogenic dyslipidemia that is associated with obesity, diabetes, and metabolic syndrome. Numerous models of obesity are characterized by increased central nervous system (CNS) neuropeptide Y (NPY) tone that contributes to excess food intake and obesity. Previously, we demonstrated that intracerebroventricular (icv) administration of NPY in lean fasted rats also elevates hepatic production of very low-density lipoprotein (VLDL)-TG. Thus, we hypothesize that elevated CNS NPY action contributes to not only the pathogenesis of obesity but also dyslipidemia. Here, we sought to determine whether the effects of NPY on feeding and/or obesity are dissociable from effects on hepatic VLDL-TG secretion. Pair-fed, icv NPY-treated, chow-fed Long-Evans rats develop hypertriglyceridemia in the absence of increased food intake and body fat accumulation compared with vehicle-treated controls. We then modulated CNS NPY signaling by icv injection of selective NPY receptor agonists and found that Y1, Y2, Y4, and Y5 receptor agonists all induced hyperphagia in lean, ad libitum chow-fed Long-Evans rats, with the Y2 receptor agonist having the most pronounced effect. Next, we found that at equipotent doses for food intake NPY Y1 receptor agonist had the most robust effect on VLDL-TG secretion, a Y2 receptor agonist had a modest effect, and no effect was observed for Y4 and Y5 receptor agonists. These findings, using selective agonists, suggest the possibility that the effect of CNS NPY signaling on hepatic VLDL-TG secretion may be relatively dissociable from effects on feeding behavior via the Y1 receptor.

Mitral valve repair in severe mitral regurgitation after blunt chest trauma.

Mitral valve insufficiency is a pathological condition frequently caused by etiologies such as rheumatic heart disease, ischemic cardiomyopathy, leaflets prolapse, endocarditis, rupture of a chordae tendineae, ventricular disorders or congenital heart defects among others. Nevertheless, blunt thoracic trauma, although as a rare cause, can produce valve abnormalities. We describe a case of surgical mitral valve repair of a severe insufficiency caused by blunt chest trauma in a high energy road motorbike accident.

The adverse metabolic effects of branched-chain amino acids are mediated by isoleucine and valine.

Low-protein diets promote metabolic health in rodents and humans, and the benefits of low-protein diets are recapitulated by specifically reducing dietary levels of the three branched-chain amino acids (BCAAs), leucine, isoleucine, and valine. Here, we demonstrate that each BCAA has distinct metabolic effects. A low isoleucine diet reprograms liver and adipose metabolism, increasing hepatic insulin sensitivity and ketogenesis and increasing energy expenditure, activating the FGF21-UCP1 axis. Reducing valine induces similar but more modest metabolic effects, whereas these effects are absent with low leucine. Reducing isoleucine or valine rapidly restores metabolic health to diet-induced obese mice. Finally, we demonstrate that variation in dietary isoleucine levels helps explain body mass index differences in humans. Our results reveal isoleucine as a key regulator of metabolic health and the adverse metabolic response to dietary BCAAs and suggest reducing dietary isoleucine as a new approach to treating and preventing obesity and diabetes.

Quantitative Fluxomics of Circulating Metabolites.

Mammalian organs are nourished by nutrients carried by the blood circulation. These nutrients originate from diet and internal stores, and can undergo various interconversions before their eventual use as tissue fuel. Here we develop isotope tracing, mass spectrometry, and mathematical analysis methods to determine the direct sources of circulating nutrients, their interconversion rates, and eventual tissue-specific contributions to TCA cycle metabolism. Experiments with fifteen nutrient tracers enabled extensive accounting for both circulatory metabolic cycles and tissue TCA inputs, across fed and fasted mice on either high-carbohydrate or ketogenic diet. We find that a majority of circulating carbon flux is carried by two major cycles: glucose-lactate and triglyceride-glycerol-fatty acid. Futile cycling through these pathways is prominent when dietary content of the associated nutrients is low, rendering internal metabolic activity robust to food choice. The presented in vivo flux quantification methods are broadly applicable to different physiological and disease states.

Accesibilidad, disponibilidad y asequibilidad de medicamentos para Niños con Enfermedad Renal Crónica en Guatemala / Access, availability and affordability of medications for children with Advanced Chronic Kidney Disease in Guatemala

El artículo tiene como objetivo analizar la disponibilidad, acceso y asequibilidad de los medicamentos para niños con Enfermedad Renal Crónica (ERC) en tratamiento con hemodiálisis (HD) en un país de bajos a medianos ingresos. Se llevó a cabo un estudio transversal para determinar los medicamentos más utilizados en una unidad de hemodiálisis pediátrica, incluyendo el nombre del medicamento, dosis, frecuencia, forma farmacéutica y vía de administración. Dos farmacias dentro del perímetro del hospital, una pública y una privada, fueron consultadas para determinar el costoy disponibilidad de medicamentos genéricos y de marca. De un total de 30 pacientes de la unidad de hemodiálisis, 22 expedientes fueron revisados. En general 94% de marca se encontraban disponibles en las farmacias consultadas en comparación a un 52% de los medicamentos genéricos. En farmacias públicas, 41% de medicamentos de marca y 29% de medicamentos genéricos se encontraban disponibles. El costo promedio para un mes de tratamiento con medicamentos de marca adquiridos en una farmacia privada era de $495.00 vs $299.00 en una farmacia pública. Para medicamentos genéricos, el costo promedio correspondía a $414.00 y $239.00 en farmacias privadas y públicas respectivamente. En promedio, los medicamentos de marca adquiridos en una farmacia privada requieren 41 días de trabajo en un mes a comparación de 25 días si se adquieren en una farmacia pública. Los medicamentos genéricos adquiridos en farmacias privadas corresponden a 34 días de trabajo vs 20 días en farmacias públicas. En general existió un acceso limitado a medicamentos genéricos y los medicamentos poseen un costo general más elevado a comparación de otros países lo que implica un posible impacto en la adherencia terapéutica y los padecimientos secundarios de la ERC en los pacientes pediátricos en Guatemala. Esta realidad se puede aplicar a otros países de bajos a medianos ingresos.

This article aims to analyze the availability, access, and affordability of medications for children with advanced Chronic Kidney Disease (CKD) treated with hemodialysis (HD) in a low to middle income country (LMIC). A cross- sectional chart review was carried out to determine the most common medications used in an HD pediatric unit, including medication name, dose, frequency, dosage form, and route of administration. Two pharmacies within the hospital perimeter, one public and one private, were consulted to determine medication cost and availability for generic and brand-name equivalents. From 30 patients attending the HD unit, 22 records were reviewed. Overall, 94 % of brand name medications were available at pharmacies consulted, versus and 52% of generic medications. In public pharmacies, 41% of brand name, and 29% of generic medications were available. The average cost for a full month´s treatment for brand name drugs in the private pharmacy was 495.00 USD versus 299.00 USD in the public pharmacy. For generic drugs, the average cost was 414.00 USD, and 239.00 USD in private and public pharmacies respectively. On average, brand-name drugs in the private pharmacy cost 41 days' wages versus 25 in the public pharmacy. Generic drugs in the private pharmacy cost 34 days' wages versus 20 in the public pharmacy. Overall, there was limited access to generic medications, medications had an overall high cost compared to other countries both of which have the potential to impact treatment adherence and overall outcomes of CKD5 pediatric patients in Guatemala. This reality can be translated to other LMIC.

Peripheral Mechanisms Mediating the Sustained Antidiabetic Action of FGF1 in the Brain.

We recently reported that in rodent models of type 2 diabetes (T2D), a single intracerebroventricular (icv) injection of fibroblast growth factor 1 (FGF1) induces remission of hyperglycemia that is sustained for weeks. To clarify the peripheral mechanisms underlying this effect, we used the Zucker diabetic fatty fa/fa rat model of T2D, which, like human T2D, is characterized by progressive deterioration of pancreatic ß-cell function after hyperglycemia onset. We report that although icv FGF1 injection delays the onset of ß-cell dysfunction in these animals, it has no effect on either glucose-induced insulin secretion or insulin sensitivity. These observations suggest that FGF1 acts in the brain to stimulate insulin-independent glucose clearance. On the basis of our finding that icv FGF1 treatment increases hepatic glucokinase gene expression, we considered the possibility that increased hepatic glucose uptake (HGU) contributes to the insulin-independent glucose-lowering effect of icv FGF1. Consistent with this possibility, we report that icv FGF1 injection increases liver glucokinase activity by approximately twofold. We conclude that sustained remission of hyperglycemia induced by the central action of FGF1 involves both preservation of ß-cell function and stimulation of HGU through increased hepatic glucokinase activity.

Riluzole Impairs Cocaine Reinstatement and Restores Adaptations in Intrinsic Excitability and GLT-1 Expression.

Adaptations in glutamate signaling within the brain's reward circuitry are observed following withdrawal from several abused drugs, including cocaine. These include changes in intrinsic cellular excitability, glutamate release, and glutamate uptake. Pharmacological or optogenetic reversal of these adaptations have been shown to reduce measures of cocaine craving and seeking, raising the hypothesis that regulation of glutamatergic signaling represents a viable target for the treatment of substance use disorders. Here, we tested the hypothesis that administration of the compound riluzole, which regulates glutamate dynamics in several ways, would reduce cocaine seeking in the rat self-administration and reinstatement model of addiction. Riluzole dose-dependently inhibited cue- and cocaine-primed reinstatement to cocaine, but did not affect locomotor activity or reinstatement to sucrose seeking. Moreover, riluzole reversed bidirectional cocaine-induced adaptations in intrinsic excitability of prelimbic (PL) and infralimbic (IL) pyramidal neurons; a cocaine-induced increase in PL excitability was decreased by riluzole, and a cocaine-induced decrease in IL excitability was increased to normal levels. Riluzole also reversed the cocaine-induced suppression of the high-affinity glutamate transporter 1 (EAAT2/GLT-1) in the nucleus accumbens (NAc). GLT-1 is responsible for the majority of glutamate uptake in the brain, and has been previously reported to be downregulated by cocaine. These results demonstrate that riluzole impairs cocaine reinstatement while rectifying several cellular adaptations in glutamatergic signaling within the brain's reward circuitry, and support the hypothesis that regulators of glutamate homeostasis represent viable candidates for pharmacotherapeutic treatment of psychostimulant relapse.

Evidence That the Sympathetic Nervous System Elicits Rapid, Coordinated, and Reciprocal Adjustments of Insulin Secretion and Insulin Sensitivity During Cold Exposure.

Dynamic adjustment of insulin secretion to compensate for changes of insulin sensitivity that result from alteration of nutritional or metabolic status is a fundamental aspect of glucose homeostasis. To investigate the role of the brain in this coupling process, we used cold exposure as an experimental paradigm because the sympathetic nervous system (SNS) helps to coordinate the major shifts of tissue glucose utilization needed to ensure that increased thermogenic needs are met. We found that glucose-induced insulin secretion declined by 50% in rats housed at 5°C for 28 h, and yet, glucose tolerance did not change, owing to a doubling of insulin sensitivity. These potent effects on insulin secretion and sensitivity were fully reversed by returning animals to room temperature (22°C) for 4 h or by intravenous infusion of the α-adrenergic receptor antagonist phentolamine for only 30 min. By comparison, insulin clearance was not affected by cold exposure or phentolamine infusion. These findings offer direct evidence of a key role for the brain, acting via the SNS, in the rapid, highly coordinated, and reciprocal changes of insulin secretion and insulin sensitivity that preserve glucose homeostasis in the setting of cold exposure.

Central injection of fibroblast growth factor 1 induces sustained remission of diabetic hyperglycemia in rodents.

Type 2 diabetes (T2D) is among the most common and costly disorders worldwide. The goal of current medical management for T2D is to transiently ameliorate hyperglycemia through daily dosing of one or more antidiabetic drugs. Hypoglycemia and weight gain are common side effects of therapy, and sustained disease remission is not obtainable with nonsurgical approaches. On the basis of the potent glucose-lowering response elicited by activation of brain fibroblast growth factor (FGF) receptors, we explored the antidiabetic efficacy of centrally administered FGF1, which, unlike other FGF peptides, activates all FGF receptor subtypes. We report that a single intracerebroventricular injection of FGF1 at a dose one-tenth of that needed for antidiabetic efficacy following peripheral injection induces sustained diabetes remission in both mouse and rat models of T2D. This antidiabetic effect is not secondary to weight loss, does not increase the risk of hypoglycemia, and involves a novel and incompletely understood mechanism for increasing glucose clearance from the bloodstream. We conclude that the brain has an inherent potential to induce diabetes remission and that brain FGF receptors are potential pharmacological targets for achieving this goal.

Glucose intolerance induced by blockade of central FGF receptors is linked to an acute stress response.

OBJECTIVE: Central administration of ligands for fibroblast growth factor receptors (FGFRs) such as fibroblast growth factor-19 (FGF19) and FGF21 exert glucose-lowering effects in rodent models of obesity and type 2 diabetes (T2D). Conversely, intracerebroventricular (icv) administration of the non-selective FGFR inhibitor (FGFRi) PD173074 causes glucose intolerance, implying a physiological role for neuronal FGFR signaling in glucose homeostasis. The current studies were undertaken to identify neuroendocrine mechanisms underlying the glucose intolerance induced by pharmacological blockade of central FGFRs. METHODS: Overnight fasted, lean, male, Long-Evans rats received icv injections of either PD173074 or vehicle (Veh) followed 30 min later by performance of a frequently sampled intravenous glucose tolerance test (FSIGT). Minimal model analysis of glucose and insulin data from the FSIGT was performed to estimate insulin-dependent and insulin-independent components of glucose disposal. Plasma levels of lactate, glucagon, corticosterone, non-esterified free fatty acids (NEFA) and catecholamines were measured before and after intravenous (iv) glucose injection. RESULTS: Within 20 min of icv PD173074 injection (prior to the FSIGT), plasma levels of lactate, norepinephrine and epinephrine increased markedly, and each returned to baseline rapidly (within 8 min) following the iv glucose bolus. In contrast, plasma glucagon levels were not altered by icv FGFRi at either time point. Consistent with a previous report, glucose tolerance was impaired following icv PD173074 compared to Veh injection and, based on minimal model analysis of FSIGT data, this effect was attributable to reductions of both insulin secretion and the basal insulin effect (BIE), consistent with the inhibitory effect of catecholamines on pancreatic ß-cell secretion. By comparison, there were no changes in glucose effectiveness at zero insulin (GEZI) or the insulin sensitivity index (SI). To determine if iv glucose (given during the FSIGT) contributed to the rapid resolution of the sympathoadrenal response induced by icv FGFRi, we performed an additional study comparing groups that received iv saline or iv glucose 30 min after icv FGFRi. Our finding that elevated plasma catecholamine levels returned rapidly to baseline irrespective of whether rats subsequently received an iv bolus of saline or glucose indicates that the rapid reversal of sympathoadrenal activation following icv FGFRi was unrelated to the subsequent glucose bolus. CONCLUSIONS: The effect of acute inhibition of central FGFR signaling to impair glucose tolerance likely involves a stress response associated with pronounced, but transient, sympathoadrenal activation and an associated reduction of insulin secretion. Whether this effect is a true consequence of FGFR blockade or involves an off-target effect of the FGFR inhibitor requires additional study.

Central nervous system neuropeptide Y regulates mediators of hepatic phospholipid remodeling and very low-density lipoprotein triglyceride secretion via sympathetic innervation.

OBJECTIVE: Elevated very low-density lipoprotein (VLDL)-triglyceride (TG) secretion from the liver contributes to an atherogenic dyslipidemia that is associated with obesity, diabetes and the metabolic syndrome. Numerous models of obesity and diabetes are characterized by increased central nervous system (CNS) neuropeptide Y (NPY); in fact, a single intracerebroventricular (icv) administration of NPY in lean fasted rats elevates hepatic VLDL-TG secretion and does so, in large part, via signaling through the CNS NPY Y1 receptor. Thus, our overarching hypothesis is that elevated CNS NPY action contributes to dyslipidemia by activating central circuits that modulate liver lipid metabolism. METHODS: Chow-fed Zucker fatty (ZF) rats were pair-fed by matching their caloric intake to that of lean controls and effects on body weight, plasma TG, and liver content of TG and phospholipid (PL) were compared to ad-libitum (ad-lib) fed ZF rats. Additionally, lean 4-h fasted rats with intact or disrupted hepatic sympathetic innervation were treated with icv NPY or NPY Y1 receptor agonist to identify novel hepatic mechanisms by which NPY promotes VLDL particle maturation and secretion. RESULTS: Manipulation of plasma TG levels in obese ZF rats, through pair-feeding had no effect on liver TG content; however, hepatic PL content was substantially reduced and was tightly correlated with plasma TG levels. Treatment with icv NPY or a selective NPY Y1 receptor agonist in lean fasted rats robustly activated key hepatic regulatory proteins, stearoyl-CoA desaturase-1 (SCD-1), ADP-ribosylation factor-1 (ARF-1), and lipin-1, known to be involved in remodeling liver PL into TG for VLDL maturation and secretion. Lastly, we show that the effects of CNS NPY on key liporegulatory proteins are attenuated by hepatic sympathetic denervation. CONCLUSIONS: These data support a model in which CNS NPY modulates mediators of hepatic PL remodeling and VLDL maturation to stimulate VLDL-TG secretion that is dependent on the Y1 receptor and sympathetic signaling to the liver.

Uso de metformina y un inhibidor de SGLT2 en el manejo de lipodistrofia congénita generalizada. Reporte de caso / Use of metformin and an SGLT2 inhibitor to treat congenital generalized lipodystrophy. Case report

Resumen Introducción. La lipodistrofia congénita generalizada (LCG) es un síndrome genético autosómico recesivo extremadamente raro que se caracteriza por ausencia generalizada de tejido adiposo, deficiencia en la producción de hormonas como la leptina y complicaciones metabólicas potencialmente serias como diabetes mellitus tipo 2 (DM2), esteatohepatitis e hipertrigliceridemia. Presentación del caso. Paciente femenina de 17 años con un diagnóstico tardío de LCG y con diabetes mellitus (erróneamente clasificada como tipo I), hipertrigliceridemia severa e infecciones a repetición. Luego de introducir metformina y un inhibidor del SGLT2 en el manejo de la paciente, se logró un adecuado control metabólico. Conclusión. Con frecuencia, el desconocimiento de algunas enfermedades huérfanas lleva a diagnósticos erróneos y, por tanto, a tratamientos inadecuados que en algunos casos pueden empeorar la condición clínica de los pacientes. Por lo anterior, en el caso de la LCG, es necesario que la comunidad médica tenga una mejor comprensión de sus aspectos diagnósticos y terapéuticos para brindar un diagnóstico y tratamiento oportunos.

Abstract Introduction: Generalized congenital lipodystrophy (GDL) is an extremely rare autosomal recessive genetic syndrome characterized by generalized absence of adipose tissue, deficient production of hormones such as leptin, and potentially serious metabolic complications such as type 2 diabetes mellitus (DM2), steatohepatitis and hypertriglyceridemia. Case presentation: This is the case of a 17-year-old female patient with a late diagnosis of GDL and with diabetes mellitus (erroneously classified as type 1), severe hypertriglyceridemia and recurrent infections. Adequate metabolic control was achieved after the introduction of metformin and an SGLT2 inhibitor. Conclusion: Lack of knowledge about some orphan diseases usually leads to misdiagnosis and, therefore, to inadequate treatments that may worsen the clinical condition of patients. Therefore, in the case of GDL, the medical community should have a better understanding of its diagnostic and therapeutic aspects in order to provide timely diagnosis and treatment.

Pheochromocytoma presenting as fever of unknown origin, a case report

ABSTRACT Introduction: Pheochromocytoma is a generally benign neoplasm derived from chromaffin cells of the adrenal medulla. It is characterized by the production of large amounts of catecholamines and also by the capacity to secrete bioactive peptides such as cytokines, mainly interleukin-1 IL-1, interleukin-6 IL-6 and TNF alpha. Case presentation: 24-year-old man, who consulted for fever, myalgia, and choluria. His laboratory tests were compatible with a systemic inflammatory response without infectious or autoimmune causes. However, a fluorodeoxy-glucose positron emission tomography (FDG-PET) revealed a left adrenal mass, without extra-adrenal lesions. On admission, increased levels of differentiated urine methanephrines, elevated baseline cortisol, non-suppressed adrenocorticotrophic hormone (ACTH), and positive low dose dexamethasone suppression test for cortisol were found. With suspicion of catecholamine and ACTH-producing pheochromocytoma, a tumor resection was performed, which conspicuously resolved all alterations of the inflammatory response. The histologic findings confirmed a pheochromocytoma, but the immunostaining for ACTH was negative. A literature review and the comparison of the findings with other reported cases allowed inferring that this was a case of interleukin-producing pheochromocytoma. Conclusion: Pheochromocytoma may be a cause of febrile syndrome, with IL-6 being the main mediator, which explains the manifestations of systemic inflammation and ACTH-mediated hypercortisolism.

RESUMEN Introducción. Un feocromocitoma es una neoplasia generalmente benigna de las células cromafines de la médula suprarrenal que se caracteriza por producir grandes cantidades de catecolaminas y que tiene la capacidad de secretar citoquinas como interleucina-1 IL-1, interleucina-6 IL-6 y factor de necrosis tumoral (TNF) alfa. Presentación del caso. Paciente masculino de 24 años de edad, quien consultó por fiebre, mialgias y coluria. El sujeto presentó laboratorios compatibles con respuesta inflamatoria sistémica sin causa infecciosa o autoinmune y estudio de tomografía por emisión de positrones con fluoro-desoxiglucosa que evidenció masa suprarrenal izquierda sin lesiones extra-adrenales. Al ingreso, los niveles de metanefrinas diferenciadas en orina y de cortisol basal se encontraban elevados; la hormona adrenocorticotropa (ACTH) no estaba suprimida, y el test de supresión de cortisol con dexametasona registró rango de hipercortisolis-mo. Se sospechó diagnóstico de feocromocitoma productor de catecolaminas y ACTH, por lo que se llevó a resección tumoral, con lo cual, llamativamente, se resolvieron todas las anomalías de respuesta inflamatoria. El reporte de patología confirmó un feocromocitoma, pero la inmunotinción para ACTH fue negativa. La revisión de la literatura y la comparación de los hallazgos con otros casos reportados permitieron inferir que se trató de un feocromocitoma productor de interleucinas. Conclusión. El feocromocitoma puede ser una causa de síndrome febril, siendo la IL-6 el mediador principal que explicaría las manifestaciones de inflamación sistémica y el hipercortisolismo mediado por ACTH.

Sistemas y modelos de salud, su incidencia en las redes integradas de servicios de salud / Healthcare systems and models, their impact on integrated networks of health services / Sistemas e modelos de saúde, a sua incidência nas redes integradas de serviços de saúde

Este artículo hace una revisión sistemática de la literatura, que aporta elementos para encontrarlas relaciones existentes entre: sistemas, modelos de salud y redes integradas de servicios desalud, con el propósito de evidenciar las condiciones externas que hacen posible la conformacióny la viabilidad de una red de salud. Lo anterior teniendo como premisa fundamental que ladisociación existente entre aseguramiento y prestación de servicios de salud puede ser la causade la fragmentación del sistema, dando como resultado problemas de integralidad y continuidadde la atención al usuario. En esta revisión se obtienen como resultados: que existe una relacióndirecta y en doble vía entre las redes integradas de servicios de salud y los sistemas y modelosde salud, la cual puede constituirse en un elemento atenuador de la problemática planteada; yademás, que el hospital debe adoptar un nuevo papel, como parte integral de la red.Palabras clave: integración vertical y horizontal, niveles de atención, sistemas fragmentados,organizaciones sanitarias integradas (OSI), hospitales...

This paper makes a systematic review of the literature, which provides elements to find therelationships between: systems, health models and integrated networks of health services, withthe purpose of showing the external conditions that make possible the creation and viability ofa healthcare network. This keeping always in mind that the dissociation between insurance anda healthcare provision of services may be the cause of the fragmentation of the system, resultingin problems of integrality and continuity on attention to user. In this review, we obtainedthe following results: that there is a direct relationship in double track between the integratednetworks of health services and the systems and models of health care , which can become anattenuating element of the problem raised, and also that the hospital must adopt a new role, asan integral part of the network...

Este artigo faz revisão sistemática da literatura que aporta elementos para encontrar as relaçõesexistentes entre: sistemas, modelos de saúde e redes integradas de serviços de saúde, com opropósito de evidenciar as condições externas que fazem possível a conformação e viabilidadede uma rede de saúde. Isto tendo como premissa fundamental que a dissociação existente entreseguridade e prestação de serviços de saúde pode ser a causa da fragmentação do sistema,resultando em problemas de integralidade e continuidade da atenção ao usuário. Nesta revisãoobtiveram-se como resultados: que existe relação direta e em mão dupla entre as redes integradasde serviços de saúde e os sistemas e modelos de saúde, a qual pode se constituir emelemento atenuador da problemática esboçada; além, do que o hospital deve adotar um novopapel, como parte integral da rede...