scholarly journals MEDETOMIDINE HYDROCHLORIDE EFFICIENCY AND SAFETY IN GUINEA PIG (Cavia porcellus), IN DOSES ESTIMATED THROUGH ALLOMETRIC EXTRAPOLATION

Author(s):  
Evandro Poleze ◽  
David Brunson ◽  
Diogo Fernandes Giovanelli ◽  
Juliano Bortolo De Conti ◽  
Sheila Rezler Wosiacki ◽  
...  

In this study, medetomidine hydrochloride, an alfa2 adrenergic receptor agonist, was administered to five adult guinea pigs (three males and two females) to verify the efficiency and safety of using doses calculated by using an allometric scale. A surgical procedure was performed to insert a polyethylene cannula that advanced 2.0 to 2.5 cm into the left carotid artery until the aorta. A minimum recovery period of two days was observed before any other manipulation or pharmacological test were performed. The cannulas were washed every two days with heparinized saline flow and remained patent for two to three weeks after insertion. After surgery, each animal was placed in an open box measuring 45x25x20cm, in a quiet room with soft lighting. The “MS” group received exactly the allometrically calculated dose, while the “2MS” group received twice the allometric dose and the “½ MS” group received half the allometric dose. Parameters were measured and analyzed at 0, 5, 10, 20, 40, 60, 90 and 120 minutes after injection. Body mass was 709.6±169g, 742±172.87g and 710±160.2g for groups 1, 2 and 3, respectively. Body temperature was 101.68±0.19ºF; respiratory rate was 85.2±4.54 strokes per minute; heart rate was 297.13±3.46 beats per minute; PaO2 at 81.7±9.43mmHg; PaCO2 at 34.49±1.59mmHg; pH was measured at 7.41±0.07; hematocrit at 38.4±1.31%; total protein was 4.33±0.29g/dL, glucose was measured at 97.13±3.75mg/dL; systolic blood pressure was 85.53±2.50mmHg; diastolic pressure at 7.,40±3.74mmHg; and mean blood pressure was 78.73±1.13mmHg. Straightening postural reaction was lost at 7.20±2.05, 12.80±3.56 and 8.67±3.06 minutes for groups “2MS, MS and ½ MS”, respectively. Awakening time was 53.80±7.19, 67.20±5.54 and 55.67±11.06 minutes for groups “2MS, MS and ½ MS”, respectively. For the MS group, chemical restraint was considered “excellent” with “poor” analgesia, and for the 2MS group, it was considered “good”, also with “poor” analgesia. This means these protocols should be used for painless procedures when immobilization is necessary. The ½ MS protocol is not suitable for chemical restraint in guinea pigs. This paper presents new results obtained from research conducted in 2000.

1958 ◽  
Vol 192 (2) ◽  
pp. 345-352 ◽  
Author(s):  
W. J. Roberson ◽  
Steven M. Horvath

Twelve experiments were conducted on anesthetized and paired dogs of similar weights subjected to unimpeded, unregulated crossed circulation. Shunts were made between the carotid arteries and external jugular veins and free flow allowed for 60 minutes or longer. Statistically significant changes occurred in the mean femoral arterial blood pressures, carotid shunt blood flow, heart rate, cardiac output, cardiac work, percentage of cardiac output flowing through the shunt and pulmonary systolic and diastolic pressures of one or both animals from their control values. The mean arterial blood pressure remained at control levels for several minutes and then dropped precipitously to hypotensive levels. The lowest mean pressures between 42 and 49 mm Hg occurred within the first 16.5 minutes of the open shunt phase with a gradual return toward control levels. The volume of blood flowing through the shunt was increased initially 250% above the control carotid blood flow, followed by a reduction in flow after 15 minutes; the volume flow at this moment was still double precross circulation levels. A secondary increase in the shunt blood flow occurred throughout the remainder of the open shunt phase. In general, the heart rates and peripheral vascular resistance were slightly elevated during the open shunt phase while cardiac output and work decreased below their control values. A marked and similar increase in the percentage of the cardiac output flowing through the carotid artery was observed in both animals. During the 60 minutes of the recovery period mean arterial blood pressure, cardiac output and work tended to return to control levels while the carotid artery blood flow and pulmonary systolic and diastolic pressure remained slightly below their control values.


2015 ◽  
Vol 29 (2) ◽  
pp. 45-54 ◽  
Author(s):  
Faye S. Routledge ◽  
Judith A. McFetridge-Durdle ◽  
Marilyn Macdonald ◽  
Lynn Breau ◽  
Tavis Campbell

Ruminating about a prior anger provoking event is found to elevate blood pressure (BP) and delay BP recovery. Delayed BP recovery may be associated with increased risk of hypertension. Interventions that improve BP recovery may be beneficial for cardiovascular health. The purposes of this study were to evaluate the influence of rumination and anger on BP reactivity and recovery, to compare the effect of an exercise intervention or distraction intervention on BP recovery and to explore if exercise improved BP recovery by distracting participants from stressor-related rumination and anger. Healthy, normotensive participants (n = 79, mean age 22.2 ± 4.0 years) underwent an anger-recall interview stressor task, 3 min of exercise (walking), distraction (reading) or no-intervention (quiet sitting) and a 15 min recovery period. State anger reactivity was associated with Δ diastolic (D) BP reactivity and approached significance with Δ systolic (S) BP reactivity. Trait rumination was associated with greater SBP during recovery. Δ SBP recovery did not differ between the exercise, distraction and no-intervention groups. Although there were no differences in Δ DBP recovery between the exercise and no-intervention groups, distraction improved Δ DBP recovery compared to the exercise intervention but not the no-intervention. The proportion of anger-related thoughts (state rumination) in the exercise group did not differ from the distraction or no-intervention groups. However, a smaller proportion of participants in the distraction intervention reported an anger-related thought during recovery compared to the no-intervention group with 76% of their thoughts relating to the provided distraction. Overall, post-stressor exercise was not found to improve BP recovery while reading was effective at distracting individuals from angry thoughts (state rumination) but had no effect on BP compared to no-intervention.


2008 ◽  
Vol 31 (4) ◽  
pp. 5
Author(s):  
Brett Burstein ◽  
Kunihiro Nishida ◽  
Philippe Comtois ◽  
Louis Villenuve ◽  
Yung-Hsin Yeh ◽  
...  

Background: Connexin alterations occur in various atrial fibrillation (AF) paradigms, but their functional significance remains unclear. No data are available regarding the effects of CHF on atrial connexin expression and phosphorylation. We therefore analyzed connexin changes and their contribution to the AF substrate during the development and reversal ofCHF. Methods and Results: Dogs were allocated to three groups: CHF induced by 2-week ventricular tachypacing (CHF, n=15); CHF dogs allowed to recover for 4 weeks after 2-week tachypacing (REC, n=15) and non-paced shams (CTL, n=11). Left ventricular end-diastolic pressure increased with CHF (14.5±1.0*** vs.3.7±0.7, ***P < 0.001 vs. CTL) and normalized upon CHF recovery (5.1±1.0^†††, ^††† P < 0.001 vs. CHF). Real-time PCR and Western-blot analyses revealed connexin43 (Cx43) and connexin40 (Cx40) mRNA and protein expression to be unchanged by CHF and REC. However, CHF caused Cx43 dephosphorylation(by ~73%***) and increased Cx40/Cx43 protein ratio (by ~35%***), with both alterations completely reversing in REC. Immunofluorescent confocal microscopy confirmed connexin protein trends, with a reduction in phosphorylated Cx43 (by ~68%*** in CHF) that returned to control in REC. CHF caused conduction abnormalities (phasedelay-range and heterogeneity index, both P < 0.01) and burst pacing-induced AF prolongation (CTL 22±7s, CHF 1100±171s***, REC 884±220s***) which persisted in the recovery period, along with residual fibrosis (CTL 3.6±0.7%, CHF 14.7±1.5%***, REC13.3±2.3%***). Fibrosis physically interrupted muscle bundle continuity and anionically-based action potential model of canine atrium showed that fibrosiswas able to account for the observed conduction abnormalities. Conclusions: CHF causes connexin-dephosphorylation and Cx40/Cx43ratio increases. With CHF reversal, atrial connexin alterations recover completely, but tissue fibrosis, conduction abnormalities and a substrate forAF remain with fibrosis accounting for conduction abnormalities. Thus, althougha trial connexin changes occur with CHF, they are not essential for conduction disturbances and AF promotion, which appear rather to be related primarily tofibrotic interruption of muscle-bundle continuity.


1952 ◽  
Vol 30 (2) ◽  
pp. 125-129
Author(s):  
J. P. Adamson ◽  
J. Doupe

Intra-arterial pressures and pulse wave velocities were measured in 18 subjects whose auscultatory diastolic pressures ranged from 45 to 120 mm. Hg. Various methods were used to lower the blood pressure in the hypertensive and to raise it in nonhypertensive subjects so that pulse wave velocities might be compared in all subjects at a common diastolic pressure. The pulse wave velocities were calculated for a diastolic pressure of 80 mm. Hg. No significant differences were found between hypertensive and nonhypertensive subjects. It was concluded that a defect of arterial elasticity as gauged by pulse wave velocity is not a factor in the pathogenesis of hypertension.


Genes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 78
Author(s):  
Vaithinathan Selvaraju ◽  
Megan Phillips ◽  
Anna Fouty ◽  
Jeganathan Ramesh Babu ◽  
Thangiah Geetha

Disparities between the races have been well documented in health and disease in the USA. Recent studies show that telomere length, a marker of aging, is associated with obesity and obesity-related diseases, such as heart disease and diabetes. The current study aimed to evaluate the connection between telomere length ratio, blood pressure, and childhood obesity. The telomere length ratio was measured in 127 children from both European American (EA) and African American (AA) children, aged 6–10 years old. AA children had a significantly high relative telomere to the single copy gene (T/S) ratio compared to EA children. There was no significant difference in the T/S ratio between normal weight (NW) and overweight/obese (OW/OB) groups of either race. Blood pressure was significantly elevated in AA children with respect to EA children. Hierarchical regression analysis adjusted for race, gender, and age expressed a significant relationship between the T/S ratio and diastolic pressure. Low T/S ratio participants showed a significant increase in systolic pressure, while a high T/S ratio group showed an increase in diastolic pressure and heart rate of AA children. In conclusion, our findings show that AA children have high T/S ratio compared to EA children. The high T/S ratio is negatively associated with diastolic pressure.


2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
K Popov ◽  
A Novitskiy ◽  
Y Shvarts

Abstract Funding Acknowledgements Type of funding sources: None. Background. Many patients with COVID-19 suffer from arterial hypertension and have marked variations in blood pressure (BP) during the acute period of infection. The reasons for such changes are poorly understood. Purpose. To assess the relationship between the level of BP and the severity of changes in the main clinical and laboratory parameters in patients with arterial hypertension and with a moderate course of COVID-19 at the stage of the height of the disease. Materials and methods. The study included 86 hospitalized patients with verified coronavirus disease of moderate severity: 46 of them were male, the median age was 65 years. Patients received adequate hypertension therapy for a long time. After hospitalization, treatment was adjusted if necessary. The level of laboratory parameters in the acute period of the disease was determined, including the electrolytes, C-reactive protein (CRP), albumin, ferritin, general blood test, etc. BP measured daily. The relationship between laboratory parameters and BP level was evaluated by nonparametric correlation using the Spearman coefficient and multivariate analysis based on the "generalized nonlinear model". Results. In 67.44% of patients with hypertension, an elevated BP level (&gt;140/90) was observed against the background of moderate COVID-19. There was a significant negative correlation between the levels of CRP and BP throughout the stay in the hospital, the most significant is the 5th day of hospitalization. At the same time, a slightly stronger relationship is observed with diastolic BP (r = -0.4425) than with systolic BP (r = -0.3525). A similar trend is observed in all BP measurements. Besides, a negative correlation was found between potassium levels and BP values. The strongest association of potassium levels is with systolic BP on the day of hospitalization (r = -0.4850) and diastolic pressure on the 1st day of hospitalization (r = -0.3561). Multivariate analysis confirmed independent and reliable "influence" of CRP (p = 0.00018) and potassium (p = 0.03921) as independent predictors of diastolic pressure. Conclusions. Most patients with hypertension and moderate COVID-19 have elevated BP levels. There is a statistically significant negative relationship between the values of BP and levels of CRP and potassium. The obtained data may correspond to the existing hypothesis about the significant role of the kinin–kallikrein system in the pathogenesis of COVID-19.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Linsheng Lv ◽  
Lei Yan ◽  
Xun Liu ◽  
Miaoxia Chen

Abstract Background Endotracheal intubation is known to pose significant physiological, pharmacokinetic, and dynamic changes and postoperative respiratory complications in patients under general anesthesia. Method An RCT trial was organized by the Third Affiliated Hospital at Sun Yat-sen University, China. Patients were eligible for inclusion in the trial if they were over 60 years old and had upper-abdominal surgery during the induction of anesthesia and had enrolled in endotracheal intubations. The primary end point included cardiovascular reactions during the induction of anesthesia and endotracheal intubations and cough events during the recovery period. In the test group, 2 g of lidocaine/prilocaine cream (and in the control group, 2 g of Vaseline) were laid over the surface of the tracheal tube cuff. Results The systolic blood pressure (F value = 62.271, p < 0.001), diastolic blood pressure (F value = 150.875, p < 0.001), and heart rate (F value = 75.627, p < 0.001) of the test group were significantly lower than the control group. Cough events during the recovery period in the test group were better (spontaneous cough, χ2 value = 10.591, p < 0.001; induced cough, χ2 value =10.806, p < 0.001). Conclusion In older patients, coughing and cardiovascular reactions under anesthesia and endotracheal intubations were reduced, as a result of using lidocaine/prilocaine cream on the surface of the tracheal tube cuff. Trial registration International Clinical Trials Network NCT02017392, 2013-12-16.


1984 ◽  
Vol 66 (6) ◽  
pp. 659-663 ◽  
Author(s):  
L. T. Bannan ◽  
J. F. Potter ◽  
D. G. Beevers ◽  
J. B. Saunders ◽  
J. R. F. Walters ◽  
...  

1. Sixty-five alcoholic patients admitted for detoxification had blood pressure, withdrawal symptoms, plasma cortisol (PC) and plasma aldosteron (PA) levels, plasma renin activity (PRA), and serum dopamin β-hydroxylase (DBH) levels measured on the first and fourth days after admission. 2. On the morning after admission blood pressure was elevated (>140/90) in 32 patients (49%) and was 160/95mmHg or more in 21 (32%). PRA was initially elevated in 41 patients, PA levels in 14, and 13 patients had raised PC levels. By the fourth day, blood pressure and bio-chemical measures had fallen significantly while urine volume and sodium output, low on admission, had increased significantly. On admission urinary metanephrine levels were raised in four out of the 31 patients who had them measured. 3. The height of both the systolic and diastolic blood pressures was significantly related to the severity of the alcohol. withdrawal symptoms. Of the biochemical parameters measured, PC level correlated with systolic but not diastolic pressure, and urinary volume was inversely correlated with the height of the diastolic pressure. No relationship was found between blood pressure and PRA or PA level. 4. The pressor effect of alcohol withdrawal could be due to sympathetic nervous system overactivity, or possibly to hypercortisolaemia. The first hypothesis seems more likely.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Sally K Hammad ◽  
Min Zi ◽  
Sukhpal Prehar ◽  
Robert Little ◽  
Ludwig Neyses ◽  
...  

Introduction: Hypertension is a major risk factor for cardiac hypertrophy and heart failure. Genome wide association studies have recently identified single nucleotide polymorphisms in ATP2B1 , the gene encoding the calcium extrusion pump, plasma membrane calcium ATPase (PMCA1), as having a strong association with hypertension risk. Hypothesis: PMCA1 plays an important role in regulation of blood pressure and protection against hypertension and cardiac hypertrophy. Aims: We aim to examine whether there is a functional link between PMCA1 and blood pressure regulation, and the development of hypertension. And to determine the impact this link may have on cardiac structure and function. Methods and Results: To study the role of PMCA1 we generated a global PMCA1 heterozygous knockout mouse (PMCA1 Ht ). PMCA1 Ht mice had 46% to 52% reduction in PMCA1 protein expression compared to the WT, in aorta, heart, kidney and brain. To study the mice under hypertensive stress conditions, 3 month old PMCA1 Ht and wild type (WT) mice were infused via minipump with angiotensin II (1mg/Kg/daily) or water as a control. Upon angiotensin treatment, PMCA1 Ht mice showed a significantly greater increase in systolic (62.24±3.05 mmHg) and diastolic pressure (52.68±4.67 mmHg), in comparison to the WT (33.37±2.91 mmHg and 23.94±4.56 mmHg, respectively), P<0.001, n=12. Moreover, PMCA1 Ht mice showed a significantly greater hypertrophic response as indicated by a greater heart weight to tibia length ratio, cardiomyocyte cell size (410±18.7 μm 2 ), compared to WT mice (340.4±9.8 μm 2 ), and increased expression of B-type natriuretic peptide (BNP), 2.36 ± 0.25 fold change, n =5-6, P< 0.01. Echocardiography showed no significant changes between PMCA1 Ht and WT mice, in heart rate, and in cardiac function, as indicated by fractional shortening and ejection fraction. In addition, PMCA1 Ht mice showed no sign of lung congestion as indicated by lung weight to body weight ratio. Conclusion: ATP2B1 deletion leads to increased blood pressure and cardiac hypertrophy. This provides functional evidence that PMCA1 is involved in blood pressure regulation and protects against the development of hypertension and cardiac hypertrophy.


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