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Treatment for heart failure has experienced a major revolution in recent years, and current evidence shows that a combination of four medications (angiotensin receptor-neprilysin inhibitors + ß-blockers + mineralocorticoid receptor antagonists + sodium.glucose cotransporter 2 inhibitors) offer the greatest benefit to our patients with significant reductions in cardiovascular mortality, heart failure hospitalisations and all-cause mortality. Unfortunately, despite their proven benefits, the implementation of these therapies is still low. Clinical inertia, and unfounded fear of using these drugs might contribute to this. Recently, evidence from randomised clinical trials has shown that intensive implementation of these therapies in patients with heart failure is safe and effective. In this review, we attempt to tackle some of these misconceptions/fears regarding medical therapy for heart failure and discuss the available evidence showing the best strategies for implementation of these therapies.
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BACKGROUND: mTORC2 is a critical regulator of cytoskeleton organization, cell proliferation, and cancer cell survival. Activated mTORC2 induces maximal activation of Akt by phosphorylation of Ser-473, but regulation of Akt activity and signaling crosstalk upon growth factor stimulation are still unclear. RESULTS: We identified that NUAK1 regulates growth factor-dependent activation of Akt by two mechanisms. NUAK1 interacts with mTORC2 components and regulates mTORC2-dependent activation of Akt by controlling lysosome positioning and mTOR association with this organelle. A second mechanism involves NUAK1 directly phosphorylating Akt at Ser-473. The effect of NUAK1 correlated with a growth factor-dependent activation of specific Akt substrates. NUAK1 induced the Akt-dependent phosphorylation of FOXO1/3a (Thr-24/Thr-32) but not of TSC2 (Thr-1462). According to a subcellular compartmentalization that could explain NUAK1's differential effect on the Akt substrates, we found that NUAK1 is associated with early endosomes but not with plasma membrane, late endosomes, or lysosomes. NUAK1 was required for the Akt/FOXO1/3a axis, regulating p21CIP1, p27KIP1, and FoxM1 expression and cancer cell survival upon EGFR stimulation. Pharmacological inhibition of NUAK1 potentiated the cell death effect induced by Akt or mTOR pharmacological blockage. Analysis of human tissue data revealed that NUAK1 expression positively correlates with EGFR expression and Akt Ser-473 phosphorylation in several human cancers. CONCLUSIONS: Our results showed that NUAK1 kinase controls mTOR subcellular localization and induces Akt phosphorylation, demonstrating that NUAK1 regulates the growth factor-dependent activation of Akt signaling. Therefore, targeting NUAK1, or co-targeting it with Akt or mTOR inhibitors, may be effective in cancers with hyperactivated Akt signaling.
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BACKGROUND: Cardiovascular manifestations in patients with COVID-19 are associated with dire outcomes. Long COVID syndrome is the persistence of symptoms after acute disease and is found in up to 40% of subjects. There is little information regarding subacute echocardiographic manifestations after COVID-19, and no study has included a Mexican mestizo population. METHODS: This cross-sectional study included subjects older than 18 with an episode of COVID-19 in the last 3 months. Those with previously known cardiovascular disease were excluded. The patient´s medical history and COVID-19 information were obtained from clinical charts. We performed a transthoracic echocardiogram in every subject and determined left ventricular (LV) index mass, LV ejection fraction (LVEF), left ventricular global longitudinal strain (LV GLS), right ventricular (RV) GLS, and tricuspid annular plane systolic excursion (TAPSE). A descriptive and comparative analysis was performed based on symptom severity and persistence. RESULTS: One hundred subjects were included; 63% were classified with mild and 37% with moderate to severe COVID-19. The median of LVEF was 60% (55-60), LV GLS and RV GLS was impaired in 34% and 74% of patients, respectively. Patients with moderate to severe disease had significantly lower LVEF (Mean Difference: -3.3), TAPSE (mean difference: -1.8), and higher (worse) LV GLS (Mean Difference: 2.5) and RV GLS (mean difference: 2.9). Persistent symptoms were associated with lower TAPSE and higher RVGLS. CONCLUSIONS: Patients who recover from COVID-19 have a high prevalence of subtle RV and LV dysfunction using GLS analysis. A moderate to severe episode was associated with worse RV and LV function measured by RV GLS, TAPSE, and LV GLS. Subjects with persistent symptoms had worse RVGLS and TAPSE.
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COVID-19 , Síndrome de COVID-19 Pós-Aguda , Humanos , Estudos Transversais , COVID-19/diagnóstico por imagem , Ecocardiografia , Função Ventricular Esquerda , Volume Sistólico , Gravidade do PacienteRESUMO
Rheb is a small GTPase member of the Ras superfamily and an activator of mTORC1, a protein complex master regulator of cell metabolism, growth, and proliferation. Rheb/mTORC1 pathway is hyperactivated in proliferative diseases, such as Tuberous Sclerosis Complex syndrome and cancer. Therefore, targeting Rheb-dependent signaling is a rational strategy for developing new drug therapies. Rheb activates mTORC1 in the cytosolic surface of lysosomal membranes. Rheb's farnesylation allows its anchorage on membranes, while its proper localization depends on the prenyl-binding chaperone PDEδ. Recently, the use of PDEδ inhibitors has been proposed as anticancer agents because they interrupted KRas signaling leading to antiproliferative effects in KRas-dependent pancreatic cancer cells. However, the effect of PDEδ inhibition on the Rheb/mTORC1 pathway has been poorly investigated. Here, we evaluated the impact of a new PDEδ inhibitor, called Deltasonamide 1, in Tsc2-null MEFs, a Rheb-dependent overactivated mTORC1 cell line. By using a yeast two-hybrid assay, we first validated that Deltasonamide 1 disrupts Rheb-PDEδ interaction. Accordingly, we found that Deltasonamide 1 reduces mTORC1 targets activation. In addition, our results showed that Deltasonamide 1 has antiproliferative and cytotoxic effects on Tsc2-null MEFs but has less effect on Tsc2-wild type MEFs viability. This work proposes the pharmacological PDEδ inhibition as a new approach to target the abnormal Rheb/mTORC1 activation in Tuberous Sclerosis Complex cells.
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Although coronavirus disease 2019 (COVID-19) manifests in most cases with respiratory symptoms, other presentations can occur. Direct damage to the cardiovascular system has been reported and recently, acute myocardial injury has been identified as a risk factor for mortality. Transthoracic echocardiography is a non-invasive tool that allows the detection of myocardial damage with validated markers (left ventricular ejection fraction and global longitudinal strain). Herein, we present the echocardiographic findings in four patients with COVID-19. All cases had acute respiratory distress syndrome (100%). Three out of four had elevated levels of creatine kinase and creatine kinase myocardial band. One case had ventricular concentric remodeling (25%). All cases (100%) had altered ventricular function: two had a reduced ejection fraction (50%) and, of those available for global longitudinal strain analysis, all had abnormal global longitudinal strain (100%). One case was found to have a tricuspid vegetation of 12 × 10 mm with no other manifestation of endocarditis. All of our cases had left ventricular dysfunction as assessed by echocardiography. One of our patients had a vegetation in the tricuspid valve. Two of our cases had a reduced ejection fraction. The importance of acute cardiac injury in COVID-19 has recently been established. A recent study found it to be an independent risk factor for mortality in patients with this disease. Information regarding echocardiographic characteristics of this population is scarce. Further research to elucidate the impact of these characteristics on morbidity and mortality is urgently needed.
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A 48-year-old male with a prior diagnosis of diabetes mellitus presented to the emergency department with malaise and nausea. On work-up, he was found with hyperglycemia and high anion gap metabolic acidosis, with a blood pH < 6.94. A diagnosis of severe diabetic ketoacidosis was established; serum electrolyte analysis showed mild hyperkalemia. On work-up, a 12-lead electrocardiogram was obtained, and it showed an ST-segment elevation on anterior leads that completely resolved with diabetic ketoacidosis treatment. ST-segment elevation myocardial infarction can be a precipitant factor for diabetic ketoacidosis, and evaluation of diabetic patients with suspected myocardial infarction can be challenging since they can present with atypical or little symptoms. Hyperkalemia, which usually accompanies diabetic ketoacidosis, can cause electrocardiographic alterations that are well described, but ST-segment elevation is uncommon. A pseudomyocardial infarction pattern has been described in patients with diabetic ketoacidosis; of note, most of these patients presented severe hyperkalemia. We believe this is of great importance for clinicians because they must be able to recognize those patients that present with electrocardiographic abnormalities secondary to the metabolic alterations and those that can be experiencing actual ongoing ischemia, in order to establish an appropriate and prompt treatment.
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Abstract: Objectives: To establish a relationship between global longitudinal strain (GLS) and Galectin-3 in pre-clinical heart failure in diabetic patients. Galectin-3 is a biomarker in heart failure with depressed ejection fraction (HFdEF). The hypothesis is presented that Galectin-3 is related to GLS and can detect left ventricular dysfunction in heart failure with preserved ejection fraction. Methods: Galectin-3 and GLS were measured in 121 asymptomatic individuals: 14 diabetics with mild depressed ejection fraction (mdEF) (LVEF 47.0 ± 6.9); 76 diabetics with preserved ejection fraction (LVEF 61 ± 5.5), and 31 controls (61.7 ± 5.1). Results: Galectin-3 was elevated in all diabetics vs controls (3.46 ± 1.36 ng/ml vs 2.78 ± 0.91 ng/ml; p = .003). It was also elevated in mdEF (3.76 ± 1.12 ng/ml vs 2.78 ± 0.9 ng/ml; p = .009) and pEF subjects (3.41 ± 1.40 ng/ml vs 2.78 ± 0.9 ng/ml; p = .058), respectively, vs controls. No difference in Gal-3 was found between diabetic groups (p = .603). Diabetics had lower GLS than controls (-18.5 ± 3.9 vs -20 ± 2.6; p = .022). Diabetics with mdEF had lower GLS than those with pEF (-13.3 ± 3.41 vs -19 ± 3.2; P<.001). There was no difference in GLS with pEF compared to controls (-19.4 ± 3.2 vs -20 ± 2.6; p = .70). Conclusions: Galectin-3 is elevated in diabetic patients with mdEF, and is associated with a diminished GLS. GLS could be an early marker of left ventricular dysfunction as well as evidence of diabetic cardiomyopathy.
Resumen: Objetivos: Establecer una asociación entre deformación longitudinal global (DLG) y galectina-3 en insuficiencia cardiaca preclínica en pacientes diabéticos. Galectina-3 es un biomarcador en insuficiencia cardiaca con fracción de eyección deprimida. Nuestra hipótesis es que la DLG y galectina-3 correlacionan y pueden detectar disfunción ventricular en insuficiencia cardiaca con FEVI preservada. Métodos: Se midieron galectina-3 y DLG en 121 individuos asintomáticos: 14 diabéticos con FEVI deprimida leve (FEdl) (FEVI 47 ± 6.9); 76 diabéticos con FEVI preservada (FEp) (FEVI 61 ± 5.5) y 31 sujetos controles (FEVI 61.7 ± 5.1). Resultados: Galectina-3 se encontró elevada en todos los diabéticos vs controles (3.46 ± 1.36 ng/ml vs 2.78 ± 0.91 ng/ml; p = 0.003). Está elevada en sujetos con FEdl (3.76 ± 1.12 vs 2.78 ± 0.9 vs ng/ml p = 0.009) y FEp (3.41 ± 1.40 vs 2.78 ± 0.9 ng/ml p = 0.058), respectivamente vs controles; no encontramos diferencia en galectina-3 en ambos grupos de diabéticos (p = 0.603). Los diabéticos tienen menor DLG que los controles (-18.5 ± 3.9 vs -20 ± 2.6; p = 0.022). Los diabéticos con FEdl tienen DLG más disminuida que aquellos con FEp (-13.3 ± 3.41 vs -19 ± 3.2; p < 0.001). No existe diferencia en DLG con FEp y controles (-19.4 ± 3.2 vs -20 ± 2.6; p = 0.70). Conclusiones: Galectina-3 está elevada en diabéticos con FEdl y correlaciona DLG disminuida. DLG podría ser un marcador temprano de disfunción ventricular y evidencia en miocardiopatía diabética.
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Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Volume Sistólico , Galectina 3/sangue , Cardiomiopatias Diabéticas/fisiopatologia , Cardiomiopatias Diabéticas/sangue , Proteínas Sanguíneas , Ecocardiografia , Biomarcadores/sangue , Galectinas , Cardiomiopatias Diabéticas/diagnóstico por imagemRESUMO
BACKGROUND Amyloidosis is characterized by tissue deposition of insoluble fibrillar proteins and it affects almost every organ; there are many types and the heart can be affected in all of them. CASE REPORT Our report describes a middle-aged man who presented to the Emergency Department with congestive heart failure. Clinical, electrocardiographic, and echocardiographic findings suggested the presence of an infiltrative disease, so an abdominal fat tissue biopsy was performed. A final diagnosis of systemic amyloidosis with heart involvement was made. CONCLUSIONS This case highlights the importance of combining clinical, electrocardiographic, and echocardiographic information in the diagnosis of complex diseases like amyloidosis with heart involvement.
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Amiloidose/diagnóstico , Cardiopatias/diagnóstico , Insuficiência Cardíaca/etiologia , Mieloma Múltiplo/complicações , Amiloidose/complicações , Ecocardiografia , Eletrocardiografia , Cardiopatias/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Volume SistólicoRESUMO
OBJECTIVES: To establish a relationship between global longitudinal strain (GLS) and Galectin-3 in pre-clinical heart failure in diabetic patients. Galectin-3 is a biomarker in heart failure with depressed ejection fraction (HFdEF). The hypothesis is presented that Galectin-3 is related to GLS and can detect left ventricular dysfunction in heart failure with preserved ejection fraction. METHODS: Galectin-3 and GLS were measured in 121 asymptomatic individuals: 14 diabetics with mild depressed ejection fraction (mdEF) (LVEF 47.0±6.9); 76 diabetics with preserved ejection fraction (LVEF 61±5.5), and 31 controls (61.7±5.1). RESULTS: Galectin-3 was elevated in all diabetics vs controls (3.46±1.36 ng/ml vs 2.78±0.91 ng/ml; p=.003). It was also elevated in mdEF (3.76±1.12 ng/ml vs 2.78±0.9 ng/ml; p=.009) and pEF subjects (3.41±1.40 ng/ml vs 2.78±0.9 ng/ml; p=.058), respectively, vs controls. No difference in Gal-3 was found between diabetic groups (p=.603). Diabetics had lower GLS than controls (-18.5±3.9 vs -20±2.6; p=.022). Diabetics with mdEF had lower GLS than those with pEF (-13.3±3.41 vs -19±3.2; P<.001). There was no difference in GLS with pEF compared to controls (-19.4±3.2 vs -20±2.6; p=.70). CONCLUSIONS: Galectin-3 is elevated in diabetic patients with mdEF, and is associated with a diminished GLS. GLS could be an early marker of left ventricular dysfunction as well as evidence of diabetic cardiomyopathy.
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Cardiomiopatias Diabéticas/sangue , Cardiomiopatias Diabéticas/fisiopatologia , Galectina 3/sangue , Volume Sistólico , Biomarcadores/sangue , Proteínas Sanguíneas , Cardiomiopatias Diabéticas/diagnóstico por imagem , Ecocardiografia , Feminino , Galectinas , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
This study describes the spermatozoa of 10 of the 15 species of the Neotropical frog genus Pleurodema through transmission electron microscopy. The diversity of oviposition modes coupled with a recent phylogenetic hypothesis of Pleurodema makes it an interesting group for the study of ultrastructural sperm evolution in relation to fertilization environment and egg-clutch structure. We found that Pleurodema has an unusual variability in sperm morphology. The more variable structures were the acrosomal complex, the midpiece, and the tail. The acrosomal complex has all the structures commonly reported in hyloid frogs but with different degree of development of the subacrosomal cone. Regarding the midpiece, the variability is given by the presence or absence of the mitochondrial collar. Finally, the tail is the most variable structure, ranging from single (only axoneme) to more complex (presence of paraxonemal rod, cytoplasmic sheath, and undulating membrane), with the absence of the typical axial fiber present in hyloid frogs, also shared with some other genera of Leiuperinae. J. Morphol. 277:957-977, 2016. © 2016 Wiley Periodicals, Inc.
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Anuros/anatomia & histologia , Filogenia , Espermatozoides/ultraestrutura , Animais , Anuros/classificação , Evolução Biológica , Masculino , Mitocôndrias/ultraestruturaRESUMO
El síndrome del intestino irritable (SII) es un trastorno digestivo funcional que afecta del 10 al 20% de la población general. Existen pocos estudios en Latinoamérica que muestren su prevalencia nacional, y en Venezuela no disponemos de investigación que reporte tan importante cifra. Estudio multicéntrico, descriptivo, transversal, durante los meses abril y mayo del 2011. Se utilizó el cuestionario validado de la Fundación Roma, con quienes firmamos convenio como Servicio de Gastroenterología del Hospital Vargas de Caracas. Se seleccionaron al azar 15 estados, en cada uno un municipio, y de estos lugares como iglesias, centros comerciales, reuniones de Consejos Comunales, paradas de autobuses, etc. Los valores obtenidos fueron transcritos en una base de datos en Excel y procesados con EPIDAT 3.1. De 1781 personas encuestadas, 299 presentaron criterios clínicos diagnósticos para SII de acuerdo a Roma III. La prevalencia nacional del SII fue de 16,80%, correspondiendo 81,6% a mujeres (244) y 18,4% a hombres (55). El grupo etario entre 38 y 47 años fue el más afectado (26,43%) y el subtipo mixto el más predominante. La prevalencia del SII en la población adulta venezolana según los criterios de Roma III es de 16,80%
Irritable bowel syndrome (IBS) is a functional digestive disorder that affects 10 to 20% of the general population. Few studies exist in Latin America that shows the national prevalence, and in Venezuela we don´t have investigation resources that support those numbers. Multicenter study, descriptive, transversal, during the months April and May 2011. The validated Roma Foundation questionnaire was used. This Foundation authorized its use by the Service of Gastroenterology Hospital Vargas de Caracas. 15 states were randomly selected, in each state one municipality, and in those places as churches, shopping centers, comunity meeting, bus stops, etc. The values obtained were transcribed into a database in Excel and processed EPIDAT 3.1. Of 1781 people encuested, 299 met the criteria for IBS according to Rome III. The national prevalence of IBS was 16.80%, with 81.6% women (244) and 18.4% men (55). The age group between 38 and 47 years was the most affected (26.43%) and the mix was the most predominant subtype. The prevalence of IBS in the Venezuelan adult population according to Rome III criteria is 16.80%
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Feminino , Estudos Transversais/métodos , Síndrome do Intestino Irritável/diagnóstico , Síndrome do Intestino Irritável/epidemiologia , GastroenterologiaRESUMO
Leishmania sp. is an intracellular parasite that causes a variable degree of clinical manifestations, especially in the skin. We present the case of a 38-year-old male with a chronic history of mucocutaneous disease present since childhood that generated deformity, loss of cartilage in the ears and nose, and scarring that limited his range of motion. The parasite was identified as L. mexicana mexicana. The patient was treated with a 3-month course of oral miltefosine with overwhelming results.
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Antiprotozoários/uso terapêutico , Leishmania mexicana/isolamento & purificação , Leishmaniose Tegumentar Difusa/tratamento farmacológico , Fosforilcolina/análogos & derivados , Humanos , Leishmaniose Tegumentar Difusa/parasitologia , Fosforilcolina/uso terapêuticoRESUMO
The ultrastructure of the intermediate segment (IS), distal tubule and collecting tubule (CT) of the south american toad Bufo arenarum, was studied by light and transmission electron microscopy. The IS is composed of cubical ciliated cells which propel the urine along the renal tubule. The distal tubule is divided into two portions: the early distal tubule (EDT) and the late distal tubule (LDT). The EDT is characterized by only one type of cells with well developed basolateral interdigitations and numerous elongated mitochondria, which are oriented normal to the basal surface. The "macula densa--like" is a specialized zone of the EDT in contact with the vascular pole, where cells are more tightly packed than in the rest of the tubule. The LDT shows two types of cells called dark and light cells according to the appearance of their cytoplasm. Dark cells have microplicae and few but long microvilli at their luminal surface, and abundant mitochondria in their cytoplasm. Light cells show basal and lateral infoldings and few mitochondria. The CT, which is composed of dark and light cells, exhibits an enlarged lumen with an undulated surface and dilated spaces between neighbouring cells. This work is a contribution to the knowledge of the kidney of B. arenarum; frequently used as an experimental model for physiological and biochemical studies.
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Bufo arenarum/anatomia & histologia , Túbulos Renais Coletores/ultraestrutura , Túbulos Renais Distais/ultraestrutura , Túbulos Renais/ultraestrutura , Rim/ultraestrutura , Animais , Feminino , Rim/anatomia & histologia , MasculinoRESUMO
Background: Clostridium difficile is the main agent causing antimicrobial associated nosocomial diarrhea. Chronic renal failure is a risk factor for this type of diarrhea. Aim: To study the incidence and complications of Clostridium difficile diarrhea in a university hospital and among patients with renal diseases. Patients and methods: Retrospective review of all cases of Clostridium difficile diarrhea that occurred in a university hospital, between June 2000 and May 2001. Results: In the Nephrology Unit, 48 episodes of Clostridium difficile diarrhea occurred in 35 patients (7 cases per 100 discharges/year). This figure is higher than the global incidence in the hospital (0.53 cases per 100 discharges/year, p <0.001). The mean age of the 33 patients with renal diseases was 63 years old and 17 of them were female. Their main diagnoses were chronic renal failure in hemodialysis in 48 percent , uremic syndrome in 36 percent and renal transplant in 6 percent. Seventy nine percent had a history of antimicrobial use (42 percent quinolones and 36 percent cephalosporins). In 3 patients, the only risk factor was chronic renal failure. Seventy five percent responded to metronidazole and in 27 percent, diarrhea recidivated, compared with a 6 percent recurrence rate in other units, p <0.02). Eight patients died during hospital stay. Conclusions: Among patients with renal diseases, Clostridium difficile is frequent and associated with a high recurrence rate and mortality. Chronic renal failure may be a risk factor for its development
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Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Clostridioides difficile , Diarreia , Insuficiência Renal Crônica/complicações , Enterocolite Pseudomembranosa , Incidência , Estudos Retrospectivos , Sensibilidade e Especificidade , Diarreia , Fezes , Insuficiência Renal Crônica/diagnóstico , Técnicas Imunoenzimáticas/métodosRESUMO
The ultrastructure of the intermediate segment (IS), distal tubule and collecting tubule (CT) of the south american toad Bufo arenarum, was studied by light and transmission electron microscopy. The IS is composed of cubical ciliated cells which propel the urine along the renal tubule. The distal tubule is divided into two portions: the early distal tubule (EDT) and the late distal tubule (LDT). The EDT is characterized by only one type of cells with well developed basolateral interdigitations and numerous elongated mitochondria, which are oriented normal to the basal surface. The [quot ]macula densa--like[quot ] is a specialized zone of the EDT in contact with the vascular pole, where cells are more tightly packed than in the rest of the tubule. The LDT shows two types of cells called dark and light cells according to the appearance of their cytoplasm. Dark cells have microplicae and few but long microvilli at their luminal surface, and abundant mitochondria in their cytoplasm. Light cells show basal and lateral infoldings and few mitochondria. The CT, which is composed of dark and light cells, exhibits an enlarged lumen with an undulated surface and dilated spaces between neighbouring cells. This work is a contribution to the knowledge of the kidney of B. arenarum; frequently used as an experimental model for physiological and biochemical studies.
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Background: Hypotension occurs in 20 percent of hemodialysis procedures. Aim: To study the effects of midodrine on hypotension during hemodialysis. Patients and methods: Ten patients on chronic hemodialysis and with a history of hypotension during the procedure, were studied. They received midodrine 10 mg per os or placebo during 5 dialytic procedures each, in a double blind cross over design. Results: Blood pressure levels prior to dialysis were similar during the midodrine or placebo administration periods. During dialysis, systolic blood pressure fell 19.3ñ28 mmHg with midodrine and 23.4ñ28 mmHg with placebo. Diastolic blood pressure fell 7.3ñ11.5 mmHg with midodrine and 11.1ñ12 mmHg with placebo. The reduction in median arterial pressure was also less pronounced with midodrine. Conclusions: Midodrine lessens the fall in arterial pressure during hemodialysis, in patients with symptomatic hypotension
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Humanos , Masculino , Feminino , Midodrina , Hipotensão/tratamento farmacológico , Insuficiência Renal Crônica/complicaçõesRESUMO
The lung of the toad, Melanophryniscus stelzneri stelzneri was studied using scanning and transmission electron microscopy. In M.s.stelzneri the parenchyma forms a polygonal network arrangement, therefore the parenchyma is edicular. These spaces are delimited by the interconnection of third order septa which are covered by respiratory epithelium. Small patches of ciliated epithelium without goblet cells appear irregularly distributed on the septa. The respiratory epithelium consists of one type of pneumocyte, which shows characteristics of both type I and type II alveolar cells of higher vertebrates. The pneumocytes are irregular in shape and possess attenuated cytoplasmic processes, which spread around the capillaries to form the outer layer of the air-blood barrier. These cells contain different types of cytoplasmic bodies: electron dense bodies, multivesicular bodies and lamellar bodies. Dense bodies are probably the precursors of lamellar bodies and the multivesicular bodies are incorporated into the latter. Neuroepithelial bodies appear randomly distributed over the septa. These bodies are separated from the lumen of the lung by thin cytoplasmic processes of neighbouring pneumocytes. The air-blood barrier consists of three layers: epithelium, interstitial space and endothelium. The relatively simple pulmonary structure of M.s.stelzneri is due to a lower degree of partitioning of the pulmonary lumen in comparison to the lung of other bufonid anurans, could be correlated with a well developed cutaneous and buccopharingeal respiration. The testing of this hypothesis awaits further studies.