HEMODYNAMICS DURING THE ACUTE PHASE OF MYOCARDIAL DAMAGE CAUSED BY ISOPROTERENOL

1962 ◽  
Vol 40 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Margaret Beznak

One to three days after two consecutive subcutaneous injections of 40 mg/kg isoproterenol were given to male rats, severe histological changes occurred in the myocardium. Blood pressure, cardiac output, and work of these rats did not differ from normal. During polyvinylpyrrolidone infusion, normal rats raised their cardiac output to about three times the preinfusion value, while only a slight increase took place in the isoproterenol-treated rats. The difference was less marked during pitressin and norepinephrine infusion. It is concluded that during the acute damage of the myocardium by isoproterenol, the functional capacity of the heart is greatly reduced.

1962 ◽  
Vol 40 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Margaret Beznak

One to three days after two consecutive subcutaneous injections of 40 mg/kg isoproterenol were given to male rats, severe histological changes occurred in the myocardium. Blood pressure, cardiac output, and work of these rats did not differ from normal. During polyvinylpyrrolidone infusion, normal rats raised their cardiac output to about three times the preinfusion value, while only a slight increase took place in the isoproterenol-treated rats. The difference was less marked during pitressin and norepinephrine infusion. It is concluded that during the acute damage of the myocardium by isoproterenol, the functional capacity of the heart is greatly reduced.


1980 ◽  
Vol 59 (s6) ◽  
pp. 397s-399s ◽  
Author(s):  
E. Reisin ◽  
D. H. Suarez ◽  
E. D. Frohlich

1. The haemodynamic and plasma volume changes associated with obesity and high blood pressure were studied in nine male rats with electrolytic ventromedial hypothalamic lesions and their paired sham-operated controls. Body weight and arterial pressure were greater in the rats with ventromedial hypothalamic lesions (565 ± 16 vs 462 ± 14 g, P<0.001; 128 ± 3 vs 118 ± 3 mmHg, P<0.05, respectively). Cardiac output was slightly elevated, and that portion of cardiac output distributed to the kidneys was reduced (P<0.001). Plasma volume was contracted in the rats with ventromedial hypothalamic lesions (21.0 ± 0.1 vs 2.8 ± 0.1 ml/100 g, P<0.001). 2. The haemodynamic characteristics of rats in which obesity and mild hypertension have been induced by electrolytic ventromedial hypothalamic lesion are similar to mild obesity essential hypertension in men.


1991 ◽  
Vol 261 (5) ◽  
pp. R1118-R1125 ◽  
Author(s):  
K. Toba ◽  
J. T. Crofton ◽  
M. Inoue ◽  
L. Share

This study was performed to investigate further the mechanisms underlying the sexual dimorphism of the pressor responses to vasopressin. We have confirmed our earlier findings that the pressor response to graded infusions of vasopressin in conscious unrestrained male rats is similar to that in estrous females and greater than in diestrus, proestrus, and metestrus. This difference was due primarily to greater increases in total peripheral resistance (TPR) in males and estrous females, since there were no sex- or cycle-related differences in the vasopressin-induced reductions in cardiac output. Gonadectomy was without effect in males but, in females, increased blood pressure responses to vasopressin to levels found in males. Chronic treatment of ovariectomized rats with estradiol reduced pressor responsiveness to vasopressin; treatment with progesterone was without effect. These differences were also due to differences in TPR. It is concluded that the sex- and cycle-dependent differences in vasopressin-induced increases in blood pressure are due largely to attenuation of increases in TPR by estrogen.


1971 ◽  
Vol 49 (12) ◽  
pp. 1019-1022 ◽  
Author(s):  
R. T. Cotton ◽  
F. L. Mugashe ◽  
B. L. Gallie ◽  
H. Chan ◽  
I. H. Koven ◽  
...  

A simple, rapid, indicator-dilution method of estimating cardiac output in small animals using 125I human serum albumin has been developed. The variation of repeat determinations in a single animal was ±10%. The cardiac output in normotensive 250–350 g Wistar male rats was 217 ± 28 (±S.D.) ml/kg min−1. These results agree with others derived by more tedious methods. After the mean arterial blood pressure was reduced to 50 mm Hg for 60 min by hemorrhage the cardiac output declined to 104 ± 40 ml/kg min−1. With this method it is possible to repeat determinations of cardiac output during shock.


1970 ◽  
Vol 39 (2) ◽  
pp. 239-245 ◽  
Author(s):  
C. M. Ferrario ◽  
C. J. Dickinson ◽  
J. W. McCubbin

1. When angiotensin was infused at low rates into the vertebral arteries of anaesthetized dogs, it raised the blood pressure. When infused at similar rates intravenously or into the internal carotid artery it either did not change blood pressure, or raised it only very slightly. The difference in response was highly significant over the range of 1–50 ng kg−1 min−1. 2. During intravenous infusion at higher rates, angiotensin usually produced the well-known reflex bradycardia and fall of cardiac output, but on infusion into the vertebral arteries it rapidly raised systemic arterial pressure, often increased heart rate, and usually produced a transient increase of cardiac output. 3. Angiotensin by both routes raised peripheral resistance, but noradrenaline, by contrast, produced the same response whether it was given into the vertebral arteries or into a vein. 4. These observations suggest that part of the pressor effect of intravenous angiotensin may be mediated by a direct stimulation of some part of the hind brain.


1979 ◽  
Vol 46 (1) ◽  
pp. 36-40 ◽  
Author(s):  
P. Fournier ◽  
J. Mensch-Dechene ◽  
B. Ranson-Bitker ◽  
W. Valladares ◽  
A. Lockhart

Pulmonary vascular pressure, blood flow, and blood volume were measured in the supine and sitting positions in eight subjects with localized lung carcinoma associated with moderate airway obstruction. Supine cardiac output, pulmonary wedge (Ppw) and artery (Ppa) pressure, and pulmonary vascular resistance (PVR) were normal. Circulatory changes in sitting position were also normal: heart rate increased 13 +/- 9% (mean +/- SD); stroke volume fell 21 +/- 15%; cardiac output fell 13 +/- 19%; and arteriovenous O2 difference increased 37 +/- 21%. Neither the difference between mean Ppa and mean Ppw nor the rise of PVR from 92 +/- 25 to 122 +/- 49 dyn.s.cm-5 in sitting position were significant. Pulmonary blood volume (PBV) as measured by a dye-bolus-injection technique fell from 517 +/- 122 ml supine to 360 +/- 43 ml sitting (P less than 0.01). This decrease is best explained by closure of alveolar vessels in the upper part of the lung and by the concomitant cessation of flow in corresponding extra-alveolar vessels, which would prevent distribution of dye in the region. Circumstantial evidence suggests the latter vessels remain open under the large expanding stresses that prevail in the upper lung.


1996 ◽  
Vol 91 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Wilbert T. Jellema ◽  
Ben P. M. Imholz ◽  
Jeroen Van Goudoever ◽  
Karel H. Wesseling ◽  
Johannes J. Van Lieshout

1. The aims of this study were to determine the clinical feasibility of continuous, non-invasive Finapres recordings as a replacement for intrabrachial pressure during a 30 min head-up tilt, and the reliability of continuous cardiac output computation by pulse contour analysis from the finger arterial versus the brachial waveform. 2. In eight healthy subjects a 30 min 70° passive head-up tilt was performed. Finger arterial (FINAP) and intrabrachial (IAP) pressures were measured simultaneously. Beat-to-beat changes in stroke volume were computed using a pulse contour algorithm. 3. Accuracy (the group-averaged FINAP—IAP difference) and precision (the SD of the difference) of Finapres measurements were 4 and 9 mmHg for systolic blood pressure, −5 and 9 mmHg for mean blood pressure and −5 and 9 mmHg for diastolic blood pressure. 4. The time course of the FINAP—IAP differences during head-up tilt showed a linear trend (P < 0.001 for all pressure levels). Averaged for the group, the difference increased 7 mmHg for mean blood pressure. The difference in stroke volume computed from FINAP and IAP was 0.3 ± 5% (mean ± SD), and independent of the duration of the tilt (P > 0.05). This difference did not change at low blood pressure levels (0.5 ± 6%). 5. The qualitative performance of the Finapres allows it to be used in the clinical setting as a monitor of sudden changes in blood pressure induced by a 30 min head-up tilt. Relative changes in stroke volume, as obtained by pulse contour analysis of the finger arterial waveform, closely follow intrabrachial values during long-duration head-up tilt and associated arterial hypotension.


2015 ◽  
Vol 40 (8) ◽  
pp. 803-810 ◽  
Author(s):  
Victoria G. Rontoyanni ◽  
Kristin Werner ◽  
Thomas A.B. Sanders ◽  
Wendy L. Hall

The acute effects of drinks rich in protein (PRO) versus carbohydrate (CHO) on cardiovascular hemodynamics and reactivity are uncertain. A randomized crossover design was used to compare 400-mL isoenergetic (1.1 MJ) drinks containing whey protein (PRO; 44 g) or carbohydrate (CHO; 57 g) versus 400 mL of water in 14 healthy men. The primary and secondary outcomes were changes in cardiac output, blood pressure, systemic vascular resistance (SVR) and digital volume pulse measured prior to and 30 min following consumption at rest, during 12 min of multi-stage bicycle ergometry, and 15 min postexercise. The mean change (95% confidence interval (CI)) in resting cardiac output at 30 min was greater for CHO than for PRO or water: 0.7 (0.4 to 1.0), 0.1 (–0.2 to 0.40), and 0.0 (–0.3 to 0.3) L/min (P < 0.001), respectively; the higher cardiac output following CHO was accompanied by an increase in stroke volume and a lower SVR. The mean increments (95% CI) in cardiac output during exercise were CHO 4.7 (4.4 to 5.0), PRO 4.9 (4.6 to 5.2), and water 4.6 (4.3 to 4.9) L/min with the difference between PRO versus water being significant (P < 0.025). There were no other statistically significant differences. In summary, a CHO-rich drink increased cardiac output and lowered SVR in the resting state compared with a PRO-rich drink or water but the effect size of changes in these variables did not differ during or after exercise between CHO and PRO. Neither protein nor carbohydrate affected blood pressure reactivity to exercise.


2017 ◽  
Vol 33 (09) ◽  
pp. 605-611 ◽  
Author(s):  
Pedro Ciudad ◽  
Alex Wong ◽  
Federico Lo Torto ◽  
Yun-Fen Li ◽  
Pei-Yu Chen ◽  
...  

Background Bowel flaps are a good and reliable method to restore the continuity of the aerodigestive tract. Radiated fields, contaminated recipient sites, or depleted recipient vessels may increase the risk for ischemic injury after transfer. During ischemic events, we believe that bowel conduits with serosa have a delayed neovascularization process at its new recipient site.We conducted an ischemia/reperfusion murine model to understand the difference among bowel conduits with and without serosa. Materials and Methods Two groups of rats were compared: control group (jejunal conduit with serosa) and a target group (jejunal conduit without serosa). These conduits were harvested from the peritoneal cavity and transferred into a subcutaneous pocket. After 72 hours of transfer and pedicle ligation, histological changes related to ischemia/reperfusion were assessed. In addition, tissue markers of angiogenesis (CD34), ischemia (lactate dehydrogenase [LDH]), and inflammation (interleukin [IL]-1β and IL-6) were analyzed. Results Two groups (n = 20) of male rats were analyzed. Histology showed intact jejunal mucosa in the target group. The control group showed decreased number of mucin, globet cells, decreased height, and fragmentation of villi with the absence of intestinal glands. Markers of angiogenesis (CD34) were higher in the target group. In addition, markers of ischemia (LDH) (p = 0.0045) and inflammation (IL-1b, p = 0.0008, and IL-6, p = 0.0008) were significantly lower in the target group as compared with the control group. Conclusions In circumstances in which the recipient site does not offer an adequate and healthy bed or a vascular insult occurs, bowel flaps with less amount of serosa may be able to neovascularize faster thereby increasing its chances of survival.


1964 ◽  
Vol 42 (2) ◽  
pp. 269-274 ◽  
Author(s):  
Margaret Beznak ◽  
P. Hacker

Cardiovascular measurements were performed in rats 3–4 days, 1 week, 2 weeks, 5–6 weeks, and 4–5 months after the subcutaneous injection of 40 mg/kg isoproterenol on two consecutive days. Up to 1 week after the injections severe histological damage of the myocardium was accompanied by cardiac enlargement and impaired function: blood pressure, cardiac output and work were in the normal range under basal conditions but the maximum cardiac output and work measured during infusion of polyvinylpyrrolidone into the right side of the heart were well below normal. During the following weeks histological repair took place and the cardiovascular parameters measured were not different from those found in normal rats. This period was followed by a third stage which occurred without further interference with the heart. It consisted of thinning of the ventricular wall and aneurysm formation. All cardiovascular values (maximum and basal as well) were below normal without development of cardiac enlargement.


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