Characterization and Outcomes of SARS-CoV-2 Infection in Patients with Sarcoidosis.

To analyze the clinical characteristics and outcomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in patients with sarcoidosis from a large multicenter cohort from Southern Europe and to identify the risk factors associated with a more complicated infection. We searched for patients with sarcoidosis presenting with SARS-CoV-2 infection (defined according to the European Centre for Disease Prevention and Control guidelines) among those included in the SarcoGEAS Registry, a nationwide, multicenter registry of patients fulfilling the American Thoracic Society/European Respiratory Society/World Association of Sarcoidosis and Other Granulomatous Disorders 1999 classification criteria for sarcoidosis. A 2:1 age-sex-matched subset of patients with sarcoidosis without SARS-CoV-2 infection was selected as control population. Forty-five patients with SARS-CoV-2 infection were identified (28 women, mean age 55 years). Thirty-six patients presented a symptomatic SARS-CoV-2 infection and 14 were hospitalized (12 required supplemental oxygen, 2 intensive care unit admission and 1 mechanical ventilation). Four patients died due to progressive respiratory failure. Patients who required hospital admission had an older mean age (64.9 vs. 51.0 years, p = 0.006), a higher frequency of baseline comorbidities including cardiovascular disease (64% vs. 23%, p = 0.016), diabetes mellitus (43% vs. 13%, p = 0.049) and chronic liver/kidney diseases (36% vs. 0%, p = 0.002) and presented more frequently fever (79% vs. 35%, p = 0.011) and dyspnea (50% vs. 3%, p = 0.001) in comparison with patients managed at home. Age- and sex-adjusted multivariate analysis identified the age at diagnosis of SARS-Cov-2 infection as the only independent variable associated with hospitalization (adjusted odds ratio 1.18, 95% conficence interval 1.04-1.35). A baseline moderate/severe pulmonary impairment in function tests was associated with a higher rate of hospitalization but the difference was not statistically significant (50% vs. 23%, p = 0.219). A close monitoring of SARS-CoV-2 infection in elderly patients with sarcoidosis, especially in those with baseline cardiopulmonary diseases and chronic liver or renal failure, is recommended. The low frequency of severe pulmonary involvement in patients with sarcoidosis from Southern Europe may explain the weak prognostic role of baseline lung impairment in our study, in contrast to studies from other geographical areas.

Systemic phenotype of sarcoidosis associated with radiological stages. Analysis of 1230 patients.

BACKGROUND: To analyze the association between Scadding radiological stages of sarcoidosis at diagnosis and the disease phenotype (epidemiology, clinical presentation and extrathoracic involvement) in one of the largest cohorts of patients with sarcoidosis reported from southern Europe. METHODS: The SARCOGEAS-Study Group includes a multicenter database of consecutive patients diagnosed with sarcoidosis according to the WASOG 1999 criteria. Extrathoracic disease at diagnosis was defined according to the 2014 instrument and the clusters proposed by Schupp et al. RESULTS: We analyzed 1230 patients (712 female, mean age 47 yrs.) who showed the following Scadding radiologic stages at diagnosis: stage 0 (n = 98), stage I (n = 395), stage II (n = 500), stage III (n = 195) and stage IV (n = 42). Women were overrepresented in patients presenting with extrathoracic/extrapulmonary disease, while the diagnosis was made at younger ages in patients presenting with BHL, and at older ages in those presenting with pulmonary fibrosis (q values <0.05). Multivariable adjusted analysis showed that patients presenting with pulmonary involvement (especially those with stages II and III) had a lower frequency of concomitant systemic involvement in some specific extrathoracic clusters (cutaneous-adenopathic/musculoskeletal, ENT and neuro-ocular/OCCC) but a higher frequency for others (hepatosplenic), in comparison with patients with extrapulmonary involvement (stages 0 and I). The presence of either BHL or fibrotic lesions did not influence the systemic phenotype of patients with pulmonary involvement. CONCLUSIONS: The key determinant associated with a differentiated systemic phenotype of sarcoidosis at diagnosis was interstitial pulmonary involvement rather than the individual Scadding radiological stage.

Peroxynitrite-Induced Intracellular Ca2+ Depression in Cardiac Myocytes: Role of Sarco/Endoplasmic Reticulum Ca2+ Pump.

Several studies have shown that peroxynitrite (ONOO-), formed upon the reaction of •NO and O2-, is increased in many cardiovascular diseases and is detrimental to myocardial function. Proteins associated with Ca2+ homeostasis regulation in the heart may be involved in these effects. Thus, the aim of this study was to elucidate the mechanisms associated with ONOO--induced effects. We evaluated [Ca2+]i regulation, sarco/endoplasmic reticulum Ca2+- binding proteins, and phosphorylation levels of the ryanodine receptor in isolated rat myocytes. Electrical field-induced intracellular Ca2+ transients and contractions were recorded simultaneously. Myocytes superfused with 3-morpholinosydnonimine N-ethylcarbamide (SIN-1), an ONOO- donor, decreased the amplitude of Ca2+ transients and contraction in a dose-response (1-200 µM) manner. Similarly, SIN-1 increased half-time decay in a concentration-dependent manner. Co-infusion of the ONOO- donor with FeTMPyP (1 µM), an ONOO- decomposition catalyst, inhibited the effects induced by ONOO-. Impaired sarcoplasmic reticulum Ca2+ uptake caused by ONOO- (SIN-1 200 µM) was confirmed by a reduction of caffeine-evoked Ca2+ release along with prolongation of the half-time decay. Surprisingly, ONOO- induced a spontaneous Ca2+ transient that started at the beginning of the relaxation phase and was inhibited by tetracaine. Also, reduced phosphorylation at the ryanodine receptor 2 (RyR2)-Ser-2814 site was observed. In conclusion, deficient sarco/endoplasmic reticulum Ca2+-ATPase-mediated Ca2+ uptake concomitant with augmented Ca2+ release by RyR2 in myocytes may be associated with modification of myocyte Ca2+ handling by ONOO-. Thus, development of cardiac failure in diabetes, nephropathy, or hypertension may be related with elevated ONOO- in cardiac tissue.

Role of adenylyl cyclase in reduced ß-adrenoceptor-mediated vasorelaxation during maturation.

Beta-adrenergic receptor (ßAR)-dependent blood vessel relaxation is impaired in older animals and G protein activation has been suggested as the causative mechanism. Here, we investigated the role of ßAR subtypes (ß1AR, ß2AR, and ß3AR) and cAMP in maturation-dependent vasorelaxation impairment. Aortic rings from 15 Sprague-Dawley male rats (3 or 9 weeks old) were harvested and left intact or denuded of the endothelium. Vascular relaxation in aortic rings from younger and older groups was compared in the presence of ßAR subtype agonists and antagonists along with cAMP and cGMP antagonists. Isolated aortic rings were used to evaluate relaxation responses, protein expression was evaluated by western blot or real time PCR, and metabolites were measured by ELISA. Expression of ßAR subtypes and adenylyl cyclase was assessed, and cAMP activity was measured in vascular tissue from both groups. Isoproterenol- and BRL744-dependent relaxation in aortic rings with and without endothelium from 9-week-old rats was impaired compared with younger rats. The ß1AR antagonist CGP20712A (10-7 M) did not affect isoproterenol or BRL744-dependent relaxation in arteries from either group. The ß2AR antagonist ICI-118,551 (10-7 M) inhibited isoproterenol-dependent aortic relaxation in both groups. The ß3AR antagonist SR59230A (10-7 M) inhibited isoproterenol- and BRL744-dependent aortic ring relaxation in younger but not in older rats. All ßAR subtypes were expressed in both groups, although ß3AR expression was lower in the older group. Adenylyl cyclase (SQ 22536) or protein kinase A (H89) inhibitors prevented isoproterenol-induced relaxation in younger but not in older rats. Production of cAMP was reduced in the older group. Adenylyl cyclase III and RyR3 protein expression was higher in the younger group. In conclusion, altered expression of ß3AR and adenylyl cyclase III may be responsible for reduced cAMP production in the older group.

Role of adenylyl cyclase in reduced ß-adrenoceptor-mediated vasorelaxation during maturation

Beta-adrenergic receptor (βAR)-dependent blood vessel relaxation is impaired in older animals and G protein activation has been suggested as the causative mechanism. Here, we investigated the role of βAR subtypes (β1AR, β2AR, and β3AR) and cAMP in maturation-dependent vasorelaxation impairment. Aortic rings from 15 Sprague-Dawley male rats (3 or 9 weeks old) were harvested and left intact or denuded of the endothelium. Vascular relaxation in aortic rings from younger and older groups was compared in the presence of βAR subtype agonists and antagonists along with cAMP and cGMP antagonists. Isolated aortic rings were used to evaluate relaxation responses, protein expression was evaluated by western blot or real time PCR, and metabolites were measured by ELISA. Expression of βAR subtypes and adenylyl cyclase was assessed, and cAMP activity was measured in vascular tissue from both groups. Isoproterenol- and BRL744-dependent relaxation in aortic rings with and without endothelium from 9-week-old rats was impaired compared with younger rats. The β1AR antagonist CGP20712A (10-7 M) did not affect isoproterenol or BRL744-dependent relaxation in arteries from either group. The β2AR antagonist ICI-118,551 (10-7 M) inhibited isoproterenol-dependent aortic relaxation in both groups. The β3AR antagonist SR59230A (10-7 M) inhibited isoproterenol- and BRL744-dependent aortic ring relaxation in younger but not in older rats. All βAR subtypes were expressed in both groups, although β3AR expression was lower in the older group. Adenylyl cyclase (SQ 22536) or protein kinase A (H89) inhibitors prevented isoproterenol-induced relaxation in younger but not in older rats. Production of cAMP was reduced in the older group. Adenylyl cyclase III and RyR3 protein expression was higher in the younger group. In conclusion, altered expression of β3AR and adenylyl cyclase III may be responsible for reduced cAMP production in the older group.

Vólvulo yeyunal incompleto por linfangioma quístico mesentérico / Partial jejunal volvulus due to a mesenteric cystic lymphangioma

Los quistes mesentéricos son tumoraciones benignas poco frecuentes entre las que se encuentran los linfangiomas. Su presentación clínica es variable y pueden producir síntomas agudos debido a complicaciones. Se diagnostican sobre todo en edad pediátrica y su pronóstico, tras exéresis completa, suele ser excelente. Presentamos el caso de una paciente de 15 años con dolor abdominal postprandial y palpación de masa blanda en hipogastrio. Los estudios radiológicos mostraron una gran masa polilobulada de contenido quístico que englobaba un asa de yeyuno con volvulación incompleta. El tratamiento fue la exéresis del quiste y del asa de yeyuno y el diagnóstico anatomopatológico fue de linfangiomaquístico mesentérico. La paciente está asintomática después de más de 3 años de la intervención (AU)

Mesenteric cysts are unusual benign tumours thatinclude lymphangioma. Their clinical presentation is variable and acute symptoms can be produced due to complications. This tumour appears especially in childhood, and its prognosis after surgical removal is excellent. We present the case of a 15 year old female patient with symptoms of postprandial abdominal pain and palpation of smooth mass in hypogastrium. Radiological studies showed a big polilobular mass of cystic substance that included a portion of jejune within complete volvulus. The treatment was the removal of the cyst and a je junal portion and the pathological diagnosis was mesenteric cyst lymphangioma. The patient is asymptomatic more than three years after the intervention (AU)

[Partial jejunal volvulus due to a mesenteric cystic lymphangioma]. / Vólvulo yeyunal incompleto por linfangioma quístico mesentérico.

Mesenteric cysts are unusual benign tumours that include lymphangioma. Their clinical presentation is variable and acute symptoms can be produced due to complications. This tumour appears especially in childhood, and its prognosis after surgical removal is excellent. We present the case of a 15 year old female patient with symptoms of postprandial abdominal pain and palpation of smooth mass in hypogastrium. Radiological studies showed a big polilobular mass of cystic substance that included a portion of jejune with incomplete volvulus. The treatment was the removal of the cyst and a jejunal portion and the pathological diagnosis was mesenteric cyst lymphangioma. The patient is asymptomatic more than three years after the intervention.

Hepatits C: ¿Es adecuado el nivel de conocimiento entre médicos residentes e internos?

Objetivos: La hepatitis C constituye un serio problema de salud pública tanto a nivel mundial como en nuestro país. El objetivo de este estudio fue evaluar el nivel de conocimiento de residentes e internos de Medicina Interna con respecto al despistaje, diagnóstico y manejo de la hepatitis C. Método: Se utilizó un cuestionario donde se investigó los conocimientos básicos sobre factores de riesgos, manejo de pacientes, diagnostico y tratamiento, el cual fue suministrado a 54 médicos Residentes e Internos de 4 hospitales públicos de Maracaibo y a 31 médicos especialistas(internistas, hematólogos y gastroenterólogos). Resultados: Más de la mitad de los médicos,(61.1%) no interrogan de rutina a sus pacientes sobre presencia de factores de riesgo. La mayoría identificó como factores de alto riesgo al uso ilícito de drogas EV, transfusiones en 1982, y contactos sexuales múltiples; sin embargo 66.6% sobreestimaron factores de riesgo como el de recién nacido de madre infectada con el virus de la hepatitis C (VHC) y 90.7% sobreestimaron el de contacto sexual monogámico. Sólo un 30.5% de los participantes reportó que haría el despistaje de la hepatitis C en pacientes con ALT elevadas. Hubo una baja proporción de médicos que refieren los casos con hepatitis C al especialista (24%) y 48.1% de los residentes e internos desconoce el tratamiento actual para la hepatitis C. Conclusiones: Existe un conocimiento deficiente e inadecuado con respecto a factores de riesgo para la hepatitis C entre médicos residentes e internos, con lo cual se estaría dejando de diagnosticar una proporción significativa de pacientes con hepatitis C en esta asintomática.. Hay confusión en cuanto al manejo de los pacientes y su orientación. Para corregir las deficiencias, es importante que se desarrollen en los programas de enseñanza, actividades educacionales, más orientadas e interactivas, donde se haga hincapié en factores de riesgo, manejo y diagnóstico de la hepatitis C.

Objetive: Hepatitis C is a serious public health problem, both nationally and worldwide. The objective of this study was to assess basic knowledge of Internal Medicine Residents and Interns on factors, screening, diagnosis and management of Hepatitis C,. Method: We administered a questionnaire to 54 Internal Medicine Residents and Interns at 4 hospitals in the city of Maracaibo, as well as 31 specialists (internal medicine, hematology and gastroenterology). Results: More than half of the Interns and residents (61.6%) never asked their patients for risk factors for hepatitis C. Most of the participants identified high risk factors such as IV drug use, transfusions in 1982 and multiple sexual contacts. However, 66.6% over -estimated risk factors such as infant born to HCV infected mother, and 90.7% overestimated monogamous sexual contact. Only 30.5% of the participants reported screening for hepatitis C in patients with elevated ALT, and referral to a specialist was very low (24. Furthermore, 48.1% lacked knowledge on current therapy for hepatitis C. Conclusions: There is an inappropiate knowledge among Internal Medicine Residents and Interns with respect to risk factors. These findings may suggest that a significant proportion of patients with hepatitis C may remain undiagnosed, despite receiving medical care. There is confusion regarding management and decision making. To overcome these deficiencies, more interactive oriented ,educational activities , focusing on risk factors and management of hepatitis C, are needed and should be available in teaching programs to facilitate diagnosis in a presymptomatic stage of the disease.

Metabolic variability analysis using a mixing chamber-breath by breath based indirect calorimeter and the clino-ortho maneuver.

This work proposes the clino-ortho maneuver to analyze the metabolic energy expenditure variability by Indirect Calorimetry (IC). This analysis uses a hybrid calorimeter which includes simultaneously the mixing-chamber (MC) and the breath by breath (BbB) IC techniques. VO2 and VCO2 short-term variability was characterized as metabolic variability in the MC technique by intra-group standard deviation averages. When the BbB technique was used the metabolic variability characterization was done by VO2 and VCO2 discrete time series power spectrum analysis in the 0-0.5 Hz band. Thus a statistical population of 17 young healthy volunteers was studied using a clino-ortho maneuver with 30-30 minutes in each position after 8 hours of fasting. The results showed an energy expenditure change of 40% in Kcal/day (p<0.01). The metabolic variability was partially significant using the MC technique while BbB total power spectrum changed from 35 to 60 for the VO2 and from 24 to 37 for the VCO2 (ml/bth)(2), (p<0.05) in the region from 0 to 0.04 Hz. It was concluded that using this new measurement technique and the clino-ortho maneuver metabolic variability information not yet studied was revealed.

A simple model implementation to measure breath by breath the VO2 and VCO2 by the indirect calorimetry technique.

This paper proposes a discrete random time series modeling for the VO2 and VCO2 measurement in the indirect calorimetry technique (ICT). Mathematical equations are developed in order to establish clear differences between the breath-by-breath and mixing chamber measurement based calorimeters. This simple model offers not only a physiological ICT definition approach but also defines the idea of VO2 and VCO2 short-term variability information for research. The preliminary results show a new physiological information when a computer oriented algorithm model implementation was applied to a data acquisition system in order to obtain the power spectrum analysis from a typical observation subject submitted to the clino-ortho maneuver.

Steady State Condition in the Measurement of VO2and VCO2by Indirect Calorimetry.

Resting Metabolic Rate (RMR) is computed using VO2and VCO2short time 15-minute window measurement with Indirect Calorimetry (IC) instruments designed with mixing chamber. Steady state condition using a 10% variation coefficient criteria is the main objective to achieve metabolic long time prediction reliability. This study address how susceptible is the steady state VO2, VCO2measurement condition to the clino-orthostatic physiological maneuver. 30 young healthy subjects were analyzed. Only 18 passed the 10% variation coefficient inclusive criteria. They were exposed to 10 minutes clino-stage and 10 minutes orthostage. The hypothesis tests show not statistical significance (p< 0.1) in the average and variance analysis. It is concluded that the steady state is not influenced by the patient position IC test, probably because IC mixing chamber instruments are insensitive to detect a mayor physiological dynamics changes that can modify the steady state definition.

Angiotensin II type AT(2) receptor mRNA expression and renal vasodilatation are increased in renal failure.

Kidney failure is associated with changes in renal vascular responses to angiotensin (Ang) II. We characterized expression of Ang II receptors and the renal vasoconstrictor and vasodilator responses to Ang II in kidneys from sham-operated and kidney failure rats. In the isolated perfused kidney of sham-operated rats, Ang II (1, 2, 4, and 8 ng) increased perfusion pressure by 27+/-6, 41+/-10, 54+/-11, and 74+/-12 mm Hg, respectively. These responses were amplified by 62+/-10% (P<0.05) in kidney failure rats. Losartan (1 micromol/L), an angiotensin type 1 (AT(1)) receptor blocker, abolished renal vasoconstriction induced by Ang II, unmasking a renal vasodilatation that was greater in kidney failure rats. CGP-42112 (1 micromol/L) or PD 123,319 (1 micromol/L), angiotensin type 2 (AT(2)) receptor ligands, blunted Ang II-induced renal vasodilatation. In the renal tissue of kidney failure rats, there was a marked increase in expression of AT(1) and AT(2) mRNA receptor. Ang II-induced vasodilatation was blunted by eicosatetraynoic acid (1 micromol/L), the all-purpose inhibitor of arachidonic acid metabolism; clotrimazole (1 micromol/L), an inhibitor of epoxygenase-dependent arachidonic acid metabolism; or Nomega-nitro-L-arginine methyl ester (L-NAME; 1 micromol/L), an inhibitor of NO synthesis. On stimulation with Ang II, 20-HETE was the predominant product released into the renal effluent of sham-operated rats, whereas epoxy-eicosatrienoic acids were the predominant products released into the effluent of kidney failure rats. These data suggest that during development of kidney failure, there is induction of the AT(2) receptors, which may account for increased Ang II-dependent vasodilatation through the predominant release of epoxyeicosatrienoic acids.

Functional and cellular interactions between nitric oxide and prostacyclin.

Nitric oxide (NO) and prostacyclin (PGI(2)) can be released by vascular agents to synergize their effects on vascular relaxation. In the present study we assess whether NO could affect PGI(2) production. We evaluated the effect of NO on PGI(2)-mediated arachidonic acid (AA)-induced relaxation in the perfused heart. We used cultured endothelial cells to characterize the mechanism involved in the NO effect on PGI(2) synthesis. AA-induced PGI(2) synthesis was enhanced when NO synthesis was inhibited. NO inhibited AA-induced relaxation and PGI(2) release in the coronary circulation. S-Nitroso-acetyl-DL-penicillamine (SNAP) decreased PGI(2) production in cultured endothelial cells. The SNAP effect was blunted by the inhibitor of soluble guanylate cyclase (LY-83,583) and the blocker of cGMP-dependent protein kinases (H-9). Specific cyclooxygenase-1 (COX-1) immunoprecipitation was associated to co-precipitation of four proteins. COX-1 showed neither serine nor threonine phosphorylation. One of the proteins that co-precipitated with COX-1 presented increased serine phosphorylation in the presence of SNAP. This effect was inhibited by the H-9. We suggest that NO, through cGMP-dependent protein kinases, produces the phosphorylation of a 104-kDa protein that is associated with inhibition in the activity of the COX-1, decreasing PGI(2) synthesis and thereby decreasing coronary PGI(2)-mediated vasodilatation.

Increased renal vasoconstriction and gene expression of cyclooxygenase-1 in renovascular hypertension.

Vascular responses to arachidonic acid (AA) in the renal circulation are increased in hypertensive rats. We have suggested that these differences are related to changes in AA metabolism. In this study we investigated the mechanism involved in the increased AA-induced renal vasoconstriction. We evaluated vascular renal reactivity in the isolated perfused kidney, cyclooxygenase activity, protein content, and mRNA expression of kidneys from sham operated and aortic coarctation rats. Bolus injection of AA (1, 2, 4, and 8 microg) increased perfusion pressure in a dose-dependent manner by 20 +/- 4, 28 +/- 5, 38 +/- 6, and 44 +/- 7 mm Hg in sham-operated rats and 30 +/- 3, 55 +/- 5, 78 +/- 5, and 113 +/- 8 mm Hg in rats with aortic coarctation. Indomethacin (1 microg/ml) or the endoperoxide/thromboxane blocker SQ29548 (1 microM) prevented AA renal vasoconstriction. Cyclooxygenase activity, cyclooxygenase-1 protein content, and mRNA expression were also increased in the renal tissue from the aortic coarctation rats compared with sham-operated rats. In conclusion, we suggest that during development of hypertension, the cyclooxygenase-1 mRNA is induced, and consequently cyclooxygenase-1 activity and AA metabolism are increased, resulting in augmented production of vasoconstrictor prostaglandins that mediate the potentiated responsiveness to AA or other vascular agonists that release AA, thus increasing peripheral vascular resistance.

Una localización poco habitual de la equinococosis: quiste hidatídico mamario / An unusual localization of echinococcosis: hydatid cyst of the breast

La hidatidosis es una enfermedad endémica en Europa meridional, América del Sur, Oceanía, Asia y en ciertas áreas de África. La localización mamaria es un hallazgo excepcional. Presentamos un caso de hidatidosis mamaria en una paciente con enfermedad multivisceral. (AU)

Angiotensin II modulates ion transport in rat proximal tubules through CYP metabolites.

To assess the effect of angiotensin II on ion transport in rat isolated proximal tubules and establish the arachidonic acid cytochrome P450 metabolites' role mediating angiotensin II effect and to analyze whether corticosteroids play a role modulating this effect, we studied the effect of low (10 and 100 pM) and high (0.1-1 microM) angiotensin II concentrations on proximal tubule ion transport, measured as (86)Rb uptake. Low angiotensin II produced a stimulation on the (86)Rb uptake (195.79 +/- 35, 377.9 +/- 81, and 300 +/- 49 pg (86)Rb/microg protein/2 min, for control and 10 and 100 pM angiotensin II, respectively). High angiotensin II concentration inhibited ion transport (0.1 microM, 57.9 +/- 5 and 1 microM, 47.3 +/- 4 pg (86)Rb/microg protein/2 min), this effect was prevented by 17-ODYA and by losartan, while indomethacin had no effect. Dexamethasone treatment increased angiotensin II-induced (86)Rb uptake inhibition and arachidonic acid metabolism (19-, 20-HETE and 12-HETE), while adrenalectomy partly prevented angiotensin II-induced inhibition and decreased cytochrome P450-dependent arachidonic acid metabolism. In conclusion, high doses of angiotensin II produce inhibition of ion transport in rat isolated proximal tubules; this effect is mediated by AT(1) receptors, involves cytochrome P450-dependent arachidonic acid metabolites, and is upregulated by corticosteroids.

Nitric oxide and inducible nitric oxide synthase expression are downregulated in acute cholestasis in the rat accompanied by liver ischemia.

Hepatic blood flow decreases under cholestasis and there is evidence that NO regulates liver microvascular perfusion. Thus, the aim of the present study was to evaluate NO synthesis in cholestasis. Cholestasis was induced by bile-duct ligation (BDL) in male Wistar rats. Bilirubins and enzyme activities were measured in serum. Lipid peroxidation, GSH, GSSG and glycogen were determined in liver. Histopathological analysis was performed. Serum NO2- + NO3- concentration was measured by the Gries reaction. iNOS immunoblot analysis was carried out using an iNOS polyclonal antibody. After 7 days of BDL lipid peroxidation increased while GSH/GSSG ratio decreased. Serum NO2- + NO3- and liver iNOS protein were reduced, accompanied by ischemia as revealed by the histopathological analysis. GSH upregulates NO synthesis by increasing iNOS mRNA levels and iNOS activity, thus the reduction of GSH/GSSG ratio may be responsible for the downregulation of iNOS protein and NO synthesis, which in turn may explain the observed ischemia and the decreased hepatic blood perfusion in cholestasis reported by others.

Thiopental inhibits nitric oxide production in rat aorta.

We studied whether thiopental affects endothelial nitric oxide dependent vasodilator responses and nitrite production (an indicator of nitric oxide production) elicited by acetylcholine, histamine, and A23187 in rat aorta (artery in which nitric oxide is the main endothelial relaxant factor). In addition, we evaluated the barbiturate effect on nitric oxide synthase (NOS) activity in both rat aorta and kidney homogenates. Thiopental (10-100 microg/mL) reversibly inhibited the endothelium-dependent relaxation elicited by acetylcholine, histamine, and A23187. On the contrary, this anesthetic did not modify the endothelium-independent but cGMP-dependent relaxation elicited by sodium nitroprusside (1 nM - 1 microM) and nitroglycerin (1 nM - 1 microM), thus excluding an effect of thiopental on guanylate cyclase of vascular smooth muscle. Thiopental (100 microg/mL) inhibited both basal (87.8+/-14.3%) and acetylcholine- or A23187-stimulated (78.6+/-3.9 and 39.7+/-5.6%, respectively) production of nitrites in aortic rings. In addition the barbiturate inhibited (100 microg/mL) the NOS (45+/-4 and 42.8+/-9%) in aortic and kidney homogenates, respectively (measured as 14C-labeled citrulline production). In conclusion, thiopental inhibition of endothelium-dependent relaxation and nitrite production in aortic rings strongly suggests an inhibitory effect on NOS. Thiopental inhibition of the NOS provides further support to this contention.

Effect of cyclooxygenase-2 inhibition on renal function after renal ablation.

Kidney failure is the common end of hypertension and renal diseases. Several authors have suggested that vasodilatory prostaglandins participate in the hemodynamic mechanism responsible for the development of kidney failure. However, the mechanism by which prostaglandins are increased in renal disease is not clear. Recently, 2 isoforms of the enzyme responsible for prostaglandin synthesis, cyclooxygenase, have been described as cyclooxygenase-1 (COX-1), a constitutive isoform, and cyclooxygenase-2 (COX-2), an inducible isoform. In the present study, we investigated whether COX-2-dependent prostaglandins participate in the evolution of renal functional changes after renal ablation. We inhibited prostaglandin synthesis by COX-1 and COX-2 with indomethacin (3 mg/kg) and prostaglandin synthesis by COX-2 with NS-398 (3 mg/kg) and tested the effect of these inhibitors on the renal functional changes elicited by renal ablation. Renal ablation produced an increase in urinary volume, protein, and prostaglandin E(2), whereas urinary sodium and potassium were not affected and urinary osmolarity decreased; treatment with indomethacin or NS-398 partially prevented the renal functional changes elicited by renal ablation. Immunoblots for COX showed an increase in the expression of COX-2 protein 2 days after renal ablation. Furthermore, COX-2 mRNA expression was increased 1 day after renal ablation. These data suggest that COX-2-dependent prostaglandins participate in the renal mechanisms associated with the development of renal functional changes after renal ablation.

Renal vascular interaction of angiotensin II and prostaglandins in renovascular hypertension.

The vascular responses to angiotensin II (Ang II) in the renal circulation are increased in kidneys from rats with aortic coarctation compared with sham-operated rats. We have suggested that these differences are related to changes in mediators of the Ang II effect. The aim of this study was to investigate the role of arachidonic acid (AA) metabolites on the Ang II effect in the renal circulation of normotensive and hypertensive rats. We evaluated vascular renal reactivity in the rat isolated perfused kidney. Bolus injection of Ang II (9, 18, 36, 72 ng) increased perfusion pressure in a dose-dependent manner by 16.5+/-4, 23.5+/-4, 35.5+/-7, and 42.5+/-7 mm Hg in sham-operated rats and 50+/-6, 72+/-10, 92+/-6, and 120+/-6 mm Hg in rats with aortic coarctation. Ang II-induced vasoconstriction was prevented in hypertensive rats and potentiated in normotensive rats by the presence of indomethacin (1 microg/ml) in the perfusion solution. Furthermore, the use of the endoperoxide/thromboxane blocker (SQ29548, 1 microM) did not alter the effect of Ang II on the normotensive rats but prevented its effect in hypertensive rats. Moreover, the prostaglandin/ thromboxane (PGH2/TxA2) receptor agonist U46619 increased perfusion pressure to similar values in both kidneys from sham-operated or aortic coarctation rats. Ang II stimulated AA and prostaglandin release from isolated perfused kidneys. However, autacoid release was higher in kidneys from rats with aortic coarctation. In conclusion, we suggest that during the development of hypertension, the AA metabolism of vasoconstrictor prostaglandins is increased, and it mediates the vasoconstrictive effects of Ang II.