Central angiotensinergic mechanisms in female spontaneously hypertensive rats treated with estradiol

Estrogens reduce 0.3 M NaCl intake and palatability in a widely used model of essential hypertension, the spontaneously hypertensive rats (SHRs). Here we investigated whether the inhibitory effects of β-estradiol (E2, 10 μg/kg b.w. subcutaneously for 8 days) on water deprived partially-rehydrated (WD-PR) ovariectomized (OVX) adult female SHRs (fSHRs, n = 4-10/group) are related to interferences on brain angiotensin II AT1 receptors (AT1r). After WD-PR, E2 reduced 0.3 M NaCl intake (1.3 ± 0.6, vs. vehicle: 3.5 ± 1.2 ml/30 min), the number of hedonic responses to intraoral NaCl infusion (57 ± 11, vs. vehicle: 176 ± 32/min), and the relative angiotensin AT1r (Agtr1a) mRNA expression in the hypothalamus. Losartan (AT1r antagonist, 100 μg) intracerebroventricularly in OVX fSHRs treated with vehicle subcutaneously abolished 0.3 M NaCl intake (0.1 ± 0.1 ml/30 min) and only transiently reduced hedonic responses to intraoral NaCl. Losartan combined with E2 decreased the number of hedonic and increased the number of aversive responses to intraoral NaCl and abolished 0.3 M NaCl intake. E2 also reduced the pressor and dipsogenic responses to intracerebroventricular angiotensin II. The results suggest that AT1r activation increases palatability and induces NaCl intake in WD-PR fSHRs. E2 reduced hypothalamic Agtr1a mRNA expression, which may account for the effects of E2 on NaCl intake and palatability and intracerebroventricular angiotensin II-induced pressor and dipsogenic responses in OVX fSHRs. Future studies considering natural fluctuations in estrogen secretion might help to determine the degree of such interference in brain neuronal activity.

Sodium palatability in male spontaneously hypertensive rats

Spontaneously hypertensive rats (SHRs) ingest more NaCl than normotensive strains. Here we investigated NaCl intake and taste reactivity in adult male SHRs and normotensive Holtzman rats treated or not with AT1 receptor antagonist centrally in euhydrated condition and after fluid depletion. Taste reactivity was measured by the number of orofacial expressions to intra-oral infusions of 0.3 M NaCl. In euhydrated condition, intra-oral infusions of 0.3 M NaCl produced greater number of hedonic responses in SHRs than in normotensive rats, without differences in the number of aversive responses. Compared to euhydrated condition, the treatment with the diuretic furosemide + low dose of captopril (angiotensin converting enzyme blocker) increased the number of hedonic and reduced the number of aversive responses to intra-oral NaCl in normotensive rats, without changing the number of hedonic or aversive responses in SHRs. Losartan (AT1 receptor antagonist, 100 ng/1 μl) injected intracerebroventricularly in SHRs abolished 0.3 M NaCl intake induced by water deprivation + partial rehydration, whereas only transiently (first 30 min of the 60 min test) reduced hedonic responses, without changes in aversive responses to intra-oral NaCl. Losartan intracerebroventricularly also only transiently (first 30 min) reduced the number of hedonic responses to intra-oral NaCl in euhydrated SHRs. The results suggest that NaCl palatability is increased and independent from body fluid balance in SHRs. The results also suggest that central AT1 receptors are part of the mechanisms activated to increase NaCl intake and palatability in SHRs. A partial dissociation between NaCl intake and palatability in SHRs is also suggested.

Blockade of ERK1/2 activation with U0126 or PEP7 reduces sodium appetite and angiotensin II-induced pressor responses in spontaneously hypertensive rats

Spontaneously hypertensive rats (SHRs) have increased daily or induced sodium intake compared to normotensive rats. In normotensive rats, angiotensin II (ANG II)-induced sodium intake is blocked by the inactivation of p42/44 mitogen-activated protein kinase, also known as extracellular signal-regulated protein kinase1/2 (ERK1/2). Here we investigated if inhibition of ERK1/2 pathway centrally would change sodium appetite and intracerebroventricular (icv) ANG II-induced pressor response in SHRs. SHRs (280-330 g, n = 07-14/group) with stainless steel cannulas implanted in the lateral ventricle (LV) were used. Water and 0.3 M NaCl intake was induced by the treatment with the diuretic furosemide + captopril (angiotensin converting enzyme blocker) subcutaneously or 24 h of water deprivation (WD) followed by 2 h of partial rehydration with only water (PR). The blockade of ERK1/2 activation with icv injections of U0126 (MEK1/2 inhibitor, 2 mM; 2 μl) reduced 0.3 M NaCl intake induced by furosemide + captopril (5.0 ± 1.0, vs. vehicle: 7.3 ± 0.7 mL/120 min) or WD-PR (4.6 ± 1.3, vs. vehicle: 10.3 ± 1.4 mL/120 min). PEP7 (selective inhibitor of AT1 receptor-mediated ERK1/2 activation, 2 nmol/2 μL) icv also reduced WD-PR-induced 0.3 M NaCl (2.8 ± 0.7, vs. vehicle: 6.8 ± 1.4 mL/120 min). WD-PR-induced water intake was also reduced by U0126 or PEP7. In addition, U0126 or PEP7 icv reduced the pressor response to icv ANG II. Therefore, the present results suggest that central AT1 receptor-mediated ERK1/2 activation is part of the mechanisms involved in sodium appetite and ANG II-induced pressor response in SHRs.

Interference with the renin-angiotensin system reduces the palatability of 0.3 M NaCl in sodium-deplete rats

The renin-angiotensin system (RAS) controls hypertonic NaCl intake driven by sodium appetite. Here we investigated whether the antagonism of RAS interferes with hedonic and aversive orofacial motor responses, or palatability, to intraoral infusion of 0.3 M NaCl (hNaCl). Adult rats were depleted of sodium by combined sc injection of furosemide and 24 h removal of ambient sodium. In experiment 1, losartan (AT1 angiotensin II receptor antagonist, intracerebroventricular, 200 μg/μl), produced a three-fold increase in aversive orofacial motor responses to hNaCl. Losartan also suppressed hNaCl intake recorded immediately thereafter. In experiment 2, each animal had repeated recordings of hNaCl intake and orofacial responses to hNaCl distributed for 180 min. Paired recordings of intake and orofacial responses occurred within five successive blocks after the recordings of only orofacial responses when the animals were still sodium deplete (block zero). Captopril (angiotensin converting enzyme blocker, intraperitoneal, 30 mg/kg) inhibited by 75% the hedonic orofacial responses to hNaCl in blocks zero and 1. The hedonic responses to captopril remained the same throughout blocks, but became similar to vehicle from blocks 2 to 5. There was no difference in aversive responses to 0.3 M NaCl between captopril and vehicle. Captopril produced a 70-100% inhibition of hNaCl intake in blocks 1 to 5. The results suggest that angiotensin II acts in the brain increasing the palatability of hypertonic sodium during the consummatory phase of sodium appetite.

Redefining Cut-Points for High Symptom Burden of the Global Initiative for Chronic Obstructive Lung Disease Classification in 18,577 Patients With Chronic Obstructive Pulmonary Disease

BACKGROUND

Patients with chronic obstructive pulmonary disease (COPD) can be classified into groups A/C or B/D based on symptom intensity. Different threshold values for symptom questionnaires can result in misclassification and, in turn, different treatment recommendations. The primary aim was to find the best fitting cut-points for Global initiative for chronic Obstructive Lung Disease (GOLD) symptom measures, with an modified Medical Research Council dyspnea grade of 2 or higher as point of reference.

METHODS

After a computerized search, data from 41 cohorts and whose authors agreed to provide data were pooled. COPD studies were eligible for analyses if they included, at least age, sex, postbronchodilator spirometry, modified Medical Research Council, and COPD Assessment Test (CAT) total scores.

MAIN OUTCOMES

Receiver operating characteristic curves and the Youden index were used to determine the best calibration threshold for CAT, COPD Clinical Questionnaire, and St. Georges Respiratory Questionnaire total scores. Following, GOLD A/B/C/D frequencies were calculated based on current cut-points and the newly derived cut-points.

FINDINGS

A total of 18,577 patients with COPD [72.0% male; mean age: 66.3 years (standard deviation 9.6)] were analyzed. Most patients had a moderate or severe degree of airflow limitation (GOLD spirometric grade 1, 10.9%; grade 2, 46.6%; grade 3, 32.4%; and grade 4, 10.3%). The best calibration threshold for CAT total score was 18 points, for COPD Clinical Questionnaire total score 1.9 points, and for St. Georges Respiratory Questionnaire total score 46.0 points.

CONCLUSIONS

The application of these new cut-points would reclassify about one-third of the patients with COPD and, thus, would impact on individual disease management. Further validation in prospective studies of these new values are needed.

[Effects of environmental tobacco smoke on lower respiratory system of children under 5 years of age]

OBJECTIVE

To determine the effects of second-hand smoke in the respiratory system of children under 5 years old.

METHODS

A cross sectional study of a total of 1,104 children under 5 years old. Information about respiratory symptoms and illness, family history of respiratory diseases, smoking habits of household members and housing conditions were assessed by home interviews with the children's parents.

RESULTS

We studied 546 boys and 558 girls. Among 611 children exposed to second-hand smoke, 82% had respiratory problems (odds ratio = 1.64; 95% confidence interval: 1.21-2.20). Children whose parents were smokers at the time of the survey were more likely to experience wheezing than children of nonsmoking parents (odds ratio = 1.66; 95% confidence interval: 1.21-2.27), shortness of breath (odds ratio = 1.91; 95% confidence interval: 1. 36-2.67), morning and day time or night coughs (odds ratio = 1.58; 95% confidence interval: 1.09-2.28). The odds ratio for asthma, bronchitis and pneumonia was greater for children exposed to second-hand smoke (odds ratio = 1.60; 95% confidence interval: 1. 11-2.31).

CONCLUSIONS

Maternal smoking, paternal smoking, family history of respiratory diseases, and housing conditions are considered risk factors for respiratory diseases in children.

[Respiratory morbidity in patients with and without pulmonary obstructive syndrome after upper abdominal surgery]

BACKGROUND

We wanted to determine the postoperative pulmonary complication after upper abdominal surgery in patients with pulmonary obstrutive syndrome.

METHODS

We have studied 196 patients prospectively analyzed in preoperative period with spirometry and followed for observation of PPC. The patients were divided in four groups: COPD - those with chronic bronchitis or emphysema and VEF1/CVF< 70% (27 patients). ASMA - patients with obstruction of the airway in response to provoking stimuli (44 patients). CHRONIC BRONCHITIS-EMPHYSEMA - those with the clinical diagnoses of the respective diseases but VEF1/CVF > 70% (23 patients). NORMAL - patients without pulmonary disease and normal spirometry (102 patients).

RESULTS

Postoperative pulmonary complication was recognized when the patient presented atelectasis with clinical or gasometric alterations; bronchospasm that needed bronchodilator therapy; respiratory failure; mechanical ventilation or orotracheal intubation more than 48 hours in postsurgery period; tracheobronchitis characterized by the presence of purulent sputum with normal x-ray; pneumonia. Patients with pulmonary obstruction had experienced higher rates of pulmonary complications (32% vs 6%, p<0.05). The presence of obstructive lung disease was associated with an increased number of ventilator days, but was not associated with longer intensive care unit or hospital stay.

CONCLUSIONS

The incidence of postoperative pulmonary complications was strongly associated with the presence of pulmonary obstructive syndrome.

Prospective assessment of the risk of postoperative pulmonary complications in patients submitted to upper abdominal surgery

OBJECTIVE

To investigate associations between preoperative variables and postoperative pulmonary complications (PPC) in elective upper abdominal surgery.

DESIGN

Prospective clinical trial.

SETTING

A tertiary university hospital.

PATIENTS

408 patients were prospectively analyzed during the preoperative period and followed up postoperatively for pulmonary complications.

MEASUREMENTS

Patient characteristics, with clinical and physical evaluation, related diseases, smoking habits, and duration of surgery. Preoperative pulmonary function tests (PFT) were performed on 247 patients.

RESULTS

The postoperative pulmonary complication rate was 14 percent. The significant predictors in univariate analyses of postoperative pulmonary complications were: age >50, smoking habits, presence of chronic pulmonary disease or respiratory symptoms at the time of evaluation, duration of surgery >210 minutes and comorbidity (p <0.04). In a logistic regression analysis, the statistically significant predictors were: presence of chronic pulmonary disease, surgery lasting >210 and comorbidity (p <0.009).

CONCLUSIONS

There were three major clinical risk factors for pulmonary complications following upper abdominal surgery: chronic pulmonary disease, comorbidity, and surgery lasting more than 210 minutes. Those patients with three risk factors were three times more likely to develop a PPC compared to patients without any of these risk factors (p <0.001). PFT is indicated when there are uncertainties regarding the patient's pulmonary status.

[Acute myeloid leukemia after treatment of Hodgkin's disease]

The development of acute leukemia, particularly acute myeloid leukemia, represents a serious complication in patients treated with radio and/or chemotherapy for Hodgkin's disease. It has been reported with increasing frequency in the last years. Two such cases, that occurred in 87 patients treated for Hodgkin's disease, are reported. Complete autopsy was performed in both. The patients were less than 30 years old, received combined therapy during a prolonged time (more than 12 months), with an interval superior to 44 months between the diagnosis of Hodgkin's disease and the appearance of acute myeloid leukemia. The survival time was less than 12 months. Residual Hodgkin's disease was not observed.