Use of intracranial compliance to assist arterial blood pressure adjustment in critical patients: Short report and review of the literature.

Background: Blood pressure management is extremely important to prevent cerebral hypoxia and influence the outcome of critically ill patients. In medicine, precise instruments are essential to increase patient safety in the intensive care unit (ICU), including intracranial compliance (ICC) monitoring. A new technology developed by Brain4care, makes it possible to analyze the waveform of intracranial pressure (ICP) non-invasively associated with ICC, and this instrument was used in the patient for monitoring. Case Description: A 40-year-old male underwent aortic endocarditis surgery involving 182-min extracorporeal circulation and 9-min aortic clamping. Post-surgery, he exhibited a seizure bilateral mydriasis, followed by isochoric pupils and rapid foot movements. Neuroprotection measures were applied in the ICU, with noninvasive ICC monitoring initiated to assess intervention effectiveness. Conclusion: The non-invasive measurement of ICP can help clinical decision-making regarding the optimization of adapted protocols for neuroprotection in the ICU.

Nutrient intakes from complementary foods are associated with cardiometabolic biomarkers among undernourished Peruvian children.

Relatively little is known about how the diet of chronically undernourished children may impact cardiometabolic biomarkers. The objective of this exploratory study was to characterise relationships between dietary patterns and the cardiometabolic profile of 153 3-5-year-old Peruvian children with a high prevalence of chronic undernutrition. We collected monthly dietary recalls from children when they were 9-24 months old. At 3-5 years, additional dietary recalls were collected, and blood pressure, height, weight, subscapular skinfolds and fasting plasma glucose, insulin and lipid profiles were assessed. Nutrient intakes were expressed as average density per 100 kcals (i) from 9 to 24 months and (ii) at follow-up. The treelet transform and sparse reduced rank regress'ion (RRR) were used to summarize nutrient intake data. Linear regression models were then used to compare these factors to cardiometabolic outcomes and anthropometry. Linear regression models adjusting for subscapular skinfold-for-age Z-scores (SSFZ) were then used to test whether observed relationships were mediated by body composition. 26 % of children were stunted at 3-5 years old. Both treelet transform and sparse RRR-derived child dietary factors are related to protein intake and associated with total cholesterol and SSFZ. Associations between dietary factors and insulin were attenuated after adjusting for SSFZ, suggesting that body composition mediated these relationships. Dietary factors in early childhood, influenced by protein intake, are associated with cholesterol profiles, fasting glucose and body fat in a chronically undernourished population.

Connexin 40-Mediated Regulation of Systemic Circulation and Arterial Blood Pressure.

Vascular system is a complex network in which different cell types and vascular segments must work in concert to regulate blood flow distribution and arterial blood pressure. Although paracrine/autocrine signaling is involved in the regulation of vasomotor tone, direct intercellular communication via gap junctions plays a central role in the control and coordination of vascular function in the microvascular network. Gap junctions are made up by connexin (Cx) proteins, and among the four Cxs expressed in the cardiovascular system (Cx37, Cx40, Cx43, and Cx45), Cx40 has emerged as a critical signaling pathway in the vessel wall. This Cx is predominantly found in the endothelium, but it is involved in the development of the cardiovascular system and in the coordination of endothelial and smooth muscle cell function along the length of the vessels. In addition, Cx40 participates in the control of vasomotor tone through the transmission of electrical signals from the endothelium to the underlying smooth muscle and in the regulation of arterial blood pressure by renin-angiotensin system in afferent arterioles. In this review, we discuss the participation of Cx40-formed channels in the development of cardiovascular system, control and coordination of vascular function, and regulation of arterial blood pressure.

A comparison of four common mathematical models to assess baroreflex sensitivity.

Different methods have been used to assess baroreflex gain in experiments where changes in the carotid sinus pressure or the arterial blood pressure using different techniques provoke a baroreflex response, usually a rapid variation of heart rate. Four mathematical models are most used in the literature: the linear regression, the piecewise regression, and two different four-parameter logistic equations: equation 1, Y = (A1-D1)/[1 + eB1(X - C1) ] + D1; equation 2, Y = (A2-D2)/[1 + (X/C2)B2 ] + D2. We compared the four models regarding the best fit to previously published data in all vertebrate classes. The linear regression had the worst fit in all cases. The piecewise regression generally exhibited a better fit than the linear regression, though it returned a similar fit when no breakpoints were found. The logistic equations showed the best fit among the tested models and were similar to each other. We demonstrate that equation 2 is asymmetric and the level of asymmetry is accentuated according to B2. This means that the baroreflex gain calculated when X = C2 is different from the actual maximum gain. Alternatively, the symmetric equation 1 returns the maximum gain when X = C1. Furthermore, the calculation of baroreflex gain using equation 2 disregards that baroreceptors may reset when individuals experience different mean arterial pressures. Finally, the asymmetry from equation 2 is a mathematical artifact inherently skewed to the left of C2, thus bearing no biological meaning. Therefore, we suggest that equation 1 should be used instead of equation 2.

Photoplethysmography waveform analysis for classification of vascular tone and arterial blood pressure: Study based on neural networks.

BACKGROUND: To test whether a Shallow Neural Network (S-NN) can detect and classify vascular tone dependent changes in arterial blood pressure (ABP) by advanced photopletysmographic (PPG) waveform analysis. METHODS: PPG and invasive ABP signals were recorded in 26 patients undergoing scheduled general surgery. We studied the occurrence of episodes of hypertension (systolic arterial pressure (SAP) >140 mmHg), normotension and hypotension (SAP < 90 mmHg). Vascular tone according to PPG was classified in two ways: 1) By visual inspection of changes in PPG waveform amplitude and dichrotic notch position; where Classes I-II represent vasoconstriction (notch placed >50% of PPG amplitude in small amplitude waves), Class III normal vascular tone (notch placed between 20-50% of PPG amplitude in normal waves) and Classes IV-V-VI vasodilation (notch <20% of PPG amplitude in large waves). 2) By an automated analysis, using S-NN trained and validated system that combines seven PPG derived parameters. RESULTS: The visual assessment was precise in detecting hypotension (sensitivity 91%, specificity 86% and accuracy 88%) and hypertension (sensitivity 93%, specificity 88% and accuracy 90%). Normotension presented as a visual Class III (III-III) (median and 1st-3rd quartiles), hypotension as a Class V (IV-VI) and hypertension as a Class II (I-III); all p < .0001. The automated S-NN performed well in classifying ABP conditions. The percentage of data with correct classification by S-ANN was 83% for normotension, 94% for hypotension, and 90% for hypertension. CONCLUSIONS: Changes in ABP were correctly classified automatically by S-NN analysis of the PPG waveform contour.

Blood-pressure-waveform monitoring without interruptions due to changes in arterial compliance: The use of the vibrational and volume-clamp methods.

The arterial-blood-pressure (ABP) waveform can be monitored by the volume-clamp method. The photoplethysmography (PPG) signal is measured and clamped at maximum arterial compliance (PPGcmax) by controlling the external pressure (EP) with a cuff. PPGcmax is determined by the volume-oscillometric method though ABP measurement is regularly interrupted. To overcome this drawback, the vibrational method superimposes high-frequency vibrations on EP and measures the PPG response to estimate the "vibrational" compliance (Cv) and the PPGcmax. This method, though, has never been validated or implemented simultaneously with the volume-clamp method because the control has always been unstable. We implemented a custom-made device with a novel control system, monitoring stability and adapting the gain at high frequencies, plus lower-amplitude EP vibrations. We compared, in eleven volunteers, the EP at PPGcmax determined by the volume-oscillometric and the vibrational methods. Both exhibited a good linear correlation (r2 >0.92) and Bland-Altman agreement (95% confidence interval <15 mmHg). Moreover, in three volunteers, the vibrational and volume-clamp methods were implemented together while experimentally changing the ABP and/or Cv without manifesting control-system instability. Cv measured with the vibrational method could be used by the volume-clamp method to measure the ABP waveform without any interruptions due to changes in arterial compliance.

Blood Pressure Morphology Assessment from Photoplethysmogram and Demographic Information Using Deep Learning with Attention Mechanism.

Arterial blood pressure (ABP) is an important vital sign from which it can be extracted valuable information about the subject's health. After studying its morphology it is possible to diagnose cardiovascular diseases such as hypertension, so ABP routine control is recommended. The most common method of controlling ABP is the cuff-based method, from which it is obtained only the systolic and diastolic blood pressure (SBP and DBP, respectively). This paper proposes a cuff-free method to estimate the morphology of the average ABP pulse (ABPM¯) through a deep learning model based on a seq2seq architecture with attention mechanism. It only needs raw photoplethysmogram signals (PPG) from the finger and includes the capacity to integrate both categorical and continuous demographic information (DI). The experiments were performed on more than 1100 subjects from the MIMIC database for which their corresponding age and gender were consulted. Without allowing the use of data from the same subjects to train and test, the mean absolute errors (MAE) were 6.57 ± 0.20 and 14.39 ± 0.42 mmHg for DBP and SBP, respectively. For ABPM¯, R correlation coefficient and the MAE were 0.98 ± 0.001 and 8.89 ± 0.10 mmHg. In summary, this methodology is capable of transforming PPG into an ABP pulse, which obtains better results when DI of the subjects is used, potentially useful in times when wireless devices are becoming more popular.

Glycated Hemoglobin and Blood Pressure Levels in Adults With Type 2 Diabetes: How Many Patients Are on Target?

OBJECTIVES: Achieving glycated hemoglobin (A1C) and blood pressure targets is an important strategy for preventing chronic vascular complications in diabetes. Our aim in this study was to determine the proportion of type 2 diabetes patients who meet the recommended A1C and arterial blood pressure targets and to identify the determinants of failure to do so. METHODS: A cross-sectional study was conducted in an outpatient endocrine clinic at a university hospital. The A1C goal was 7% in general and 8% for patients with advanced chronic complications. Regarding blood pressure, the overall expected target was 140/90 mmHg. RESULTS: A total of 602 type 2 diabetes patients were analyzed: 62% were female, 14% self-reported as black, mean age was 63±11 years, mean diabetes duration was 17±9 years and median A1C was 8.0% (interquartile range, 7.0% to 9.5%). Macrovascular disease was present in 33% of the patients, diabetic retinopathy in 47%, peripheral neuropathy in 43% and diabetic kidney disease in 56%. Regarding metabolic control, 403 (67%) patients were not at the adjusted target A1C level, and being female, black, young and an insulin user were the main determinants of poor glycemic control. Regarding blood pressure, 348 (58%) patients were not at the recommended targets, and a more advanced age was the main associated factor. CONCLUSIONS: Because more than half of type 2 diabetes outpatients do not meet the recommended A1C and blood pressure target values, there is a major call to overcome the therapeutic inertia and target treatment of patients on an individual basis.

Pressão arterial sistólica em cães anestesiados: concordância entre mensurações por dois métodos não invasivos / Systolic blood pressure in anesthetized dogs: agreement between measurements by two noninvasive monitors

The oscillometric monitor is a noninvasive method used for measuring blood pressure in dogs and cats. Despite widely used, there is a large variability in the accuracy of oscillometric monitors, which may also be influenced by the location of the blood pressure cuff. The Doppler ultrasound is another non-invasive method that was shown to measure blood pressure with good accuracy and precision in small animals. The present study aimed to determine the agreement between systolic arterial pressure (SAP) measured by the Prolife P12 oscillometric monitor with 2 cuff locations and the Doppler ultrasound in anesthetized dogs. Dogs scheduled for routine anesthetic procedures were included in the study, which was carried out in 2 phases. In Phase 1, SAP values measured by the Doppler were compared with those measured by the Prolife P12 monitor with the cuff placed at the thoracic limb for both methods. In Phase 2, SAP values measured by the Doppler were compared with those measured by the Prolife P12 monitor, with the cuff placed at the thoracic limb for the Doppler and at the base of the tail for the P12. The cuff width corresponded to approximately 40% of limb or tail circumference. On all occasions, 3 consecutive measurements of SAP were recorded, followed by a single measurement of SAP by the P12, and then other 3 measurements were performed with the Doppler. The arithmetic mean of the 6 SAP measurements with the Doppler was compared with the SAP value measured by the P12 monitor (paired measurements). Agreement between SAP values measured by the Doppler and the P12 monitor was analyzed by the Bland Altman method for calculation of the bias (Doppler - P12) and standard deviation (SD) of the bias. The percentages of differences between the methods with an error ≤ 10 mmHg and ≤ 20 mmHg and Pearson's correlation coefficients were also calculated. Results were compared with the criteria from the American College of Veterinary Internal Medicine (ACVIM) for validation of noninvasive blood pressure methods. A total of 33 dogs were included in Phase 1 and 15 were included in Phase 2. During Phases 1 and 2, 179 and 87 paired measurements were recorded, respectively. Most of the measurements were recorded during normotension (SAP = 90-130 mmHg): 113/179 in Phase 1 and 52/87 in Phase 2. The bias (± SD) for Phases 1 and 2 were -2.7 ± 14.1 mmHg and 7.2 ± 25.8 mmHg. The percentages of differences ≤ 10 mmHg and ≤ 20 mmHg were: Phase 1, 61% and 83%; Phase 2, 41% and 70%. Correlation coefficients were 0.81 and 0.67 for Phases 1 and 2, respectively. According to the ACVIM criteria, maximum values accepted for bias are 10 ± 15 mmHg, the percentages of differences ≤ 10 mmHg and ≤ 20 mmHg should be ≥ 50% and ≥ 80%, respectively, and the correlation coefficient should be ≥ 0.9. When the blood pressure cuff was placed at the thoracic limb, SAP values measured by the P12 monitor met most of the ACVIM criteria, demonstrating good agreement with SAP values measured by the Doppler. The only requirement not met was the correlation coefficient which was 0.81 whereas the recommended is ≥ 0.9. Conversely, when the cuff was placed at the base of the tail, SAP values measured by the P12 monitor did not meet most of the ACVIM criteria indicating that, in anesthetized dogs, SAP measurements with the P12 monitor should be performed with the cuff placed at the thoracic limb. One limitation of this study was that most measurements fell in the normotensive range and the results should not be extrapolated for hypotensive and hypertensive conditions. In conclusion, the Prolife P12 oscillometric monitor demonstrated good agreement with SAP values measured by the Doppler and provides acceptable values in normotensive anesthetized dogs.(AU)

Qual o melhor horário da tomada da medicação anti-hipertensiva? / What is the best time to take antihypertensive medication?

A hipertensão arterial é a principal causa de morte precoce no mundo. Existem diversos fatores que contribuem para sua variação dentro da fisiologia do ritmo circadiano, e que exercem forte impacto sobre o controle da pressão arterial (PA). Os valores da PA sofrem interferência de acordo com o horário da medida. Nas primeiras horas da manhã PAS aumenta rapidamente em 20 a 25 mmHg e a PAD em 10 a 15 mmHg. As drogas anti-hipertensivas, sofrem diversas influências na sua absorção, metabolização e excreção dependentes do ritmo circadiano e de suas propriedades físico-químicas. O ciclo circadiano exerce grande impacto no controle da PA, e apenas modificando o horário das prescrições, seguindo o ritmo circadiano, talvez seja possível obter melhor controle pressórico com menor dose da medicação, reduzindo assim, as possíveis reações adversas

Hypertension is the leading cause of early death worldwide. Several factors contribute to its variation within the physiology of circadian rhythm, and these factors have a strong impact on blood pressure (BP) control. BP values are influenced by the measurement time. In the early hours of the morning, SBP increases rapidly by 20 to 25 mmHg and DBP by 10 to 15 mmHg. Antihypertensive drugs suffer from a variety of influences on their absorption, metabolism and excretion, depending on the circadian rhythm and its physical-chemical properties. The circadian cycle has a great impact on BP control, and only by changing the schedule of prescriptions, following the circadian rhythm, it may be possible to obtain better pressure control with a lower dose of medication, thus reducing potential adverse reactions

Physiological Processes Modulated by the Chloride-Sensitive WNK-SPAK/OSR1 Kinase Signaling Pathway and the Cation-Coupled Chloride Cotransporters.

The role of Cl- as an intracellular signaling ion has been increasingly recognized in recent years. One of the currently best described roles of Cl- in signaling is the modulation of the With-No-Lysine (K) (WNK) - STE20-Proline Alanine rich Kinase (SPAK)/Oxidative Stress Responsive Kinase 1 (OSR1) - Cation-Coupled Cl- Cotransporters (CCCs) cascade. Binding of a Cl- anion to the active site of WNK kinases directly modulates their activity, promoting their inhibition. WNK activation due to Cl- release from the binding site leads to phosphorylation and activation of SPAK/OSR1, which in turn phosphorylate the CCCs. Phosphorylation by WNKs-SPAK/OSR1 of the Na+-driven CCCs (mediating ions influx) promote their activation, whereas that of the K+-driven CCCs (mediating ions efflux) promote their inhibition. This results in net Cl- influx and feedback inhibition of WNK kinases. A wide variety of alterations to this pathway have been recognized as the cause of several human diseases, with manifestations in different systems. The understanding of WNK kinases as Cl- sensitive proteins has allowed us to better understand the mechanistic details of regulatory processes involved in diverse physiological phenomena that are reviewed here. These include cell volume regulation, potassium sensing and intracellular signaling in the renal distal convoluted tubule, and regulation of the neuronal response to the neurotransmitter GABA.

Increased lipopolysaccharide-induced hypothermia in neurogenic hypertension is caused by reduced hypothalamic PGE2 production and increased heat loss.

KEY POINTS: The mechanisms involved in hypothermia and fever during systemic inflammation (SI) remain largely unknown. Our data support the contention that brain-mediated mechanisms are different in hypertension during SI. Considering that, clinically, it is not easy to assess all mechanisms involved in cardiovascular and thermoregulatory control during SI, the present study sheds light on these integrated mechanisms that may be triggered simultaneously in septic hypertensive patients. The result obtained demonstrate that, in lipopolysaccharide-induced SI, an increased hypothermia is observed in neurogenic hypertension, which is caused by reduced hypothalamic prostaglandin E2 production and increased heat loss in conscious rats. Therefore, the results of the present study provide useful insight for clinical trials evaluating the thermoregulatory outcomes of septic patients with hypertension. ABSTRACT: Hypertension is a prevalent disease characterized by autonomic-induced elevated and sustained blood pressure levels and abnormal body core temperature (Tb) regulation. The present study aimed to determine the brain-mediated mechanisms involved in the thermoregulatory changes observed during lipopolysaccharide (LPS)-induced systemic inflammation (SI; at a septic-like model) in spontaneously hypertensive rats (SHR). We combined Tb and skin temperature (Tsk) analysis, assessment of prostaglandin (PG) E2 levels (the proximal mediator of fever) in the anteroventral region of the hypothalamus (AVPO; an important site for Tb control), oxygen consumption analysis, cardiovascular recordings, assays of inflammatory markers, and evaluation of oxidative stress in the plasma and brain of male Wistar rats and SHR that had received LPS (1.5 mg kg-1 ) or saline. LPS induced hypothermia followed by fever in Wistar rats, whereas, in SHR, a maintained hypothermia without fever were observed. These thermoregulatory responses were associated with an increased heat loss in SHR compared to Wistar rats. We measured LPS-induced increased PGE2 levels in the AVPO in Wistar rats, but not in SHR. The LPS-induced drop in blood pressure was higher in SHR than in Wistar rats. Furthermore, LPS-induced plasma and brain [regions involved in autonomic control: nucleus tractus solitarius (NTS) and rostral ventrolateral medulla (RVLM)] cytokine surges were blunted, whereas oxidative stress was higher in SHR. LPS-induced SI leads to blunted cytokine surges both systemically (plasma) and centrally (NTS and RVLM) and reduced hypothalamic PGE2 production, which are all associated with increased hypothermia mediated by increased heat loss, but not by heat production, in SHR.

Determinação da acurácia do monitor oscilométrico Delta Life DL 1000 na mensuração da pressão arterial em cães anestesiados de diferentes faixas de peso / Evaluation of the accuracy of the Delta Life DL 1000 oscillometric monitor for blood pressure measurement in anesthetized dogs of different weight ranges

Background: Arterial blood pressure is one of the most commonly variables monitored during anesthetic procedures in veterinary patients. The most reliable method for measuring arterial blood pressure in dogs and cats is the direct (invasive) method. However, the oscillometric method is less complex and more practical for clinical routine in small animals. Nevertheless, oscillometric monitors present great variability in accuracy. The present study aimed to determine the accuracy of the Delta Life DL 1000 oscillometric monitor for measurement of systolic, mean and diastolic blood pressures (SAP, MAP and DAP, respectively) in anesthetized dogs of different weight ranges. Materials, Methods & Results: This study was approved by the Institutional Ethics Committee of Animal Use. Fifteen female dogs of different breeds, weighing 11.6 ± 10.0 kg and with a mean age of 48 ± 51 months were used. All animals were scheduled for elective surgery under general anesthesia in the Institution Veterinary Hospital. Dogs were anesthetized with morphine, propofol and isoflurane and had a 20 or 22 gauge catheter introduced into the dorsal pedal artery for continuous, invasive monitoring of SAP, MAP and DAP. A blood pressure cuff was positioned over the middle third of the radius and connected to Delta Life DL 1000 monitor. Oscillometric readings of SAP, MAP and DAP were registered every 5 minutes, and invasive values were simultaneously recorded. Values obtained with both methods were compared (invasive versus oscillometric) by use of the Bland Altman method to determine the bias, standard deviation of bias and 95% limits of agreement. The percentages of errors between the methods within 10 mmHg and within...

A normal sodium diet preserves serum sodium levels during treatment of acute decompensated heart failure: A prospective, blind and randomized trial.

BACKGROUND: We tested the hypothesis that a normal sodium diet could be associated with preservation of serum sodium during treatment of acute decompensated heart failure (ADHF). METHODS AND RESULTS: Forty-four patients hospitalized for ADHF were blindly randomized by using block method to a low sodium diet (LS: 3 g/day of dietary sodium chloride; n = 22, 59.5 ± 11.9 y.o., 50% males. LVEF = 30.0 ± 13.6%); and a normal sodium diet (NS: 7 g/day; n = 22, 56.4 ± 10.3 y.o., 68% males; LVEF = 27.8 ± 11.7%), and both groups were submitted to fluid restriction of 1.000 mL/day. At the 7th day of intervention 16 patients of LS group and 15 patients of NS group were assessed for difference in serum sodium. Both groups had equivalent decongestion, reflected by similar percent reduction of body weight (LS: -5.0 ± 4.7% vs NS: -4.5 ± 5.2%. p = 0.41). Reduction of the N terminal fragment of type B natriuretic peptide (NT-proBNP) was significant only in the NS (-1497.0 [-18843.0 - 1191.0]. p = 0.04). The LS group showed lower levels of serum sodium (135.4 ± 3.5 mmol/L) compared to the NS group (137.5 ± 1.9 mmol/L; p = 0.04). Four cases of hyponatremia were observed only in the LS group (22%). The NS group exhibited higher mean blood pressure values (79.4 ± 2.4 mmHg vs 75.5 ± 3.0 mmHg. p = 0.03), and lower heart rate (73.2 ± 1.6 bpm vs 75.5 ± 2.1 bpm. p = 0.02). CONCLUSIONS: These results suggest that a normal sodium diet, when compared to a low sodium diet, is associated with similar degrees of decongestion, but with higher levels of natremia, blood pressure and lower neurohormonal activation during ADHF treatment. TRIAL REGISTRATION: clinicaltrials.gov Identifier no. NCT03722069.

Electronic APPS in assessing risk and monitoring of patients with arterial hypertension

The medical social significance of the arterial hypertension (AH) in the world is determined by its high prevalence, which allows to call it a non-infectious pandemic of today. The AH still remains the most common chronic disease that triggers the cardiovascular continuum, significantly reduces the body's adaptive capacity, worsens the living standards for people of socially minded age, and represents the leading global risk of increased cardiovascular mortality. The purpose of the study was comparison of informative value of various methods for measuring the arterial blood pressure (ABP) (office-based, home-based using electronic apps, and daily) in order to improve the risk assessment of the condition and monitoring the treatment efficiency for the AH patients. The method of qualitative and quantitative analysis of scientific literature and public online sources was used in the study. It has been established that the ABP analysis is an important tool to prevent the negative consequences of the AH. The results of the experimental study have revealed that hourly home-based ABP monitoring using a mobile electronic app is more informative than monitoring at long intervals, and provides information which is close to the average daily indicators obtained in the daily ABP monitoring.

Central administration of aminooxyacetate, an inhibitor of H2S production, affects thermoregulatory but not cardiovascular and ventilatory responses to hypercapnia in spontaneously hypertensive rats.

Hydrogen sulfide (H2S) is classically known for its toxic effects. More recently H2S has been documented as a neuromodulator. Here we investigated the central effects of aminooxyacetate (AOA; inhibitor of the H2S-synthesizing enzyme cystathionine ß-synthase, CBS) on cardiovascular, respiratory and thermoregulatory responses to hypercapnia in spontaneously hypertensive rats (SHR). To attain this goal we measured mean arterial pressure (MAP), heart rate (HR), ventilation (VE), and deep body temperature (Tb) of SHR and (normotensive) Wistar Kyoto (WKY) rats before and after microinjection of AOA (9 nmol/µL) or saline into the fourth ventricle immediately followed by 30-min hypercapnia exposure (7% inspired CO2). In saline-treated WKY rats, hypercapnia caused an increase in MAP accompanied by bradycardia, an increase in VE, and a drop in Tb. In AOA-treated WKY rats exposed to hypercapnia, the drug did not affect the increased MAP, potentiated the bradycardic response, attenuated the increased VE, and potentiated the drop in Tb. In saline-treated SHR, in comparison to the saline-treated WKY rats, hypercapnia elicited a minor, shorter-lasting increase in MAP with no changes in HR, evoked a greater increase in VE, and did not induce a drop in Tb. In AOA-treated SHR exposed to hypercapnia, the drug did not change the hypercapnia-induced cardiovascular and ventilatory responses while permitted a drop in Tb. Our findings indicate that AOA, an inhibitor of H2S production, modulates cardiorespiratory and thermoregulatory responses to hypercapnia in normotensive rats, whereas hypertension development in SHR is accompanied by suppression of the AOA effect on the cardiovascular and respiratory responses.

Strongyloides venezuelensis infection augments arterial blood pressure in male wistar rats.

Strongyloidiasis is an intestinal parasitosis that occurs in humans infected by Strongyloides stercoralis mostly. At its acute phase, symptoms like constipation, diarrhea and abdominal pain can be observed, but become asymptomatic for a long time, until an immunosuppression will start a hyperinfection and the dissemination of the disease, prevalent on the elderly population in tropical countries. Ivermectina treatment is the currently choice for this disease, due to its great efficacy and the results reported. It is expected that around one hundred million individuals have been infected around the world. Strongyloides venezuelensis is an intestinal helminth utilized on Strongyloidiasis investigations, in rodents. As the parasites reach the blood stream after subcutaneous infection, the larvae migrate to the lung by systemic circulation, but the effects of S. venezuelensis in the circulation remain widely unknown. Moreover, the role played by S. venezuelensis in the cardiovascular function has been understudied. Thus, the aim of this study is to determine whether acute infection with S. venezuelensis alters systemic blood pressure or not. Male wistar rats were infected subcutaneously with 2000 L3 larvae of S. venezuelensis and monitored during 21 days (Infected group), compared to a Healthy group, no infected. Oviposition, body and faeces weight, water and food intake were determined every 3 days. Moreover, systemic blood pressure was assessed by tail cuff plethysmography. At the end of experiments, the animals were euthanized and the number of worms, ventricles, lung and thymus and small intestine weight were registered. It was possible to observe that systolic blood pressure (126.86 ± 2.74 vs 155.08 ± 7.61 at 9°-day post infection - dpi - and 134.44 ± 5.22 vs 157.77 ± 9.55 at 21° dpi) and mean arterial pressure (71.72 ± 1.59 vs 80.51 ± 2.32 at 21° dpi) were markedly higher (P < 0.001) in infected group in comparison to the Healthy group. Those changes occurred after larvae passes through the circulation and demonstrated a late response to the presence of this parasite. These results suggest that host circulatory system reacts to this infection resulting in a significant increase in blood pressure.

Perinatal α-tocopherol overload programs alterations in kidney development and renal angiotensin II signaling pathways at birth and at juvenile age: Mechanisms underlying the development of elevated blood pressure.

α-Tocopherol (α-Toc) overload increases the risk of dying in humans (E.R. Miller III et al. Meta-analysis: high-dosage vitamin E supplementation may increase all-cause mortality Ann Int Med. 142 (2005) 37-46), and overload during early development leads to elevation of blood pressure at adult life, but the mechanism(s) remains unknown. We hypothesized that α-Toc overload during organogenesis affects the renal renin angiotensin system (RAS) components and renal Na+ handling, culminating with late elevated blood pressure. Pregnant Wistar rats received α-Toc or the superoxide dismutase mimetic tempol throughout pregnancy. We evaluated components of the intrarenal renin angiotensin system in neonate and juvenile offspring: Ang II-positive cells, Ang II receptors (AT1 and AT2), linked protein kinases, O2- production, NADPH oxidase abundance, lipid peroxidation and activity of Na+-transporting ATPases. In juvenile offspring we followed the evolution of arterial blood pressure. Neonates from α-Toc and tempol mothers presented with accentuated retardment in tubular development, pronounced decrease in glomerular Ang II-positive cells and AT1/AT2 ratio, intense production of O2- and upregulation of the α, ε and λ PKC isoforms. α-Toc decreased or augmented the abundance of renal (Na++K+)ATPase depending on the age and α-Toc dose. In juvenile rats the number of Ang II-positive cells returned to control values as well as PKCα, but co-existing with marked upregulation in the activity of (Na++K+) and Na+-ATPase and elevated arterial pressure at 30 days. We conclude that the mechanisms of these alterations rely on selective targeting of renal RAS components through genic and pro-oxidant effects of the vitamin.

Analysis of a Non-invasive Intracranial Pressure Monitoring Method in Patients with Traumatic Brain Injury.

OBJECTIVE: We aimed to compare the invasive (iICP) and a non-invasive intracranial pressure (nICP) monitoring methods in patients with traumatic brain injury, based on the similarities of the signals' power spectral densities. MATERIALS AND METHODS: We recorded the intracranial pressure of seven patients with traumatic brain injury admitted to Hospital São João, Portugal, using two different methods: a standard intraparenchymal (iICP) and a new nICP method based on mechanical extensometers. The similarity between the two monitoring signals was inferred from the Euclidean distance between the non-linear projection in a lower dimensional space (ISOMAP) of the windowed power spectral densities of the respective signals. About 337 h of acquisitions were used out of a total of 608 h. The only data exclusion criterion was the absence of any of the signals of interest. RESULTS: The averaged distance between iICP and nICP, and between arterial blood pressure (ABP) and nICP projections in the embedded space are statistically different for all seven patients analysed (Mann-Whitney U, p < 0.05). CONCLUSIONS: The similarity between the iICP and nICP monitoring methods was higher than the similarity between the nICP and the recordings of the radial ABP for all seven patients. Despite the possible differences between the shape of the ABP waveform at radial and parietal arteries, the results indicate-based on the similarities of iICP and nICP as functions of time-that the nICP method can be applied as an alternative method for ICP monitoring.

Evaluation of the accuracy and precision of the GE Dash 4000 oscillometric monitor for blood pressure measurement in anesthetized female dogs / Determinação da acurácia do monitor oscilométrico GE Dash 4000 na mensuração da pressão arterial em cadelas anestesiadas

Background: Indirect measurement of arterial blood pressure, such as the oscillometric method, is the most commonly used in clinical practice of dogs and cats. This method measures blood pressure values that are estimates of direct (invasive) arterial blood pressure values. Oscillometric devices are easy to use even for non-experienced personnel. However, there is considerable variation in accuracy and precision of blood pressure values measured by different oscillometric monitors. The present study aimed to determine the accuracy and precision of the GE Dash 4000 oscillometric monitor for arterial blood pressure measurement in anesthetized female dogs.Materials, Methods & Results:Sixteen healthy adult female dogs received 0.3 mg/kg morphine as premedication and were anesthetized with propofol and isoflurane. A 22-gauge catheter was introduced into the dorsal pedal artery and connected to a rigid tubular system and a pressure transducer filled with heparinized solution to allow direct (invasive) measurement of systolic (SAP), mean (MAP) and diastolic arterial pressure (DAP). A blood pressure cuff was positioned proximal to the carpus and connected to the oscillometric device (GE-DASH 4000 monitor) in order to obtain indirect measurements of SAP, MAP and DAP. Cuff width was 40% of limb circumference. During anesthesia, invasive arterial blood pressure values were measured and recorded simultaneously with the oscillometric method. The Bland Altman method was used to evaluate agreement between the methods by calculating the bias (invasive - oscillometric) and limits of agreement. Percentages of differences between the methods with an error ≤ 10 mmHg and ≤ 20 mmHg were calculated. Results were compared with the criteria from the American College of Veterinary Internal Medicine (ACVIM) for validation of noninvasive blood pressure methods.[...]