Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 15 de 15
Filter
1.
Sci Rep ; 12(1): 9707, 2022 06 11.
Article in English | MEDLINE | ID: mdl-35690664

ABSTRACT

High-doses of anabolic-androgenic steroids (AAS) is efficient for building muscle mass, but pose a risk of cardiovascular side effects. Little is known of the effect of AAS on vasculature, but previous findings suggest unfavorable alterations in vessel walls and vasoreactivity. Here, long-term effect of AAS on vascular function and morphology were examined in male weightlifters, and in a mimicking animal model. Arterial elasticity and morphology were tested with ultrasound, pulse wave velocity (PWV) and carotid intima media thickness (cIMT) in 56 current male AAS users, and 67 non-exposed weightlifting controls (WLC). Female mice were treated with testosterone for 14 days and echocardiography were applied to evaluate vascular function and morphology. Male AAS users had higher PWV (p = 0.044), reduced carotid artery compliance (p = 0.0005), and increased cIMT (p = 0.041) compared to WLC. Similar functional changes were found in the ascending aorta of mice after 7- (p = 0.043) and 14 days (p = 0.001) of testosterone treatment. This animal model can be used to map molecular mechanisms responsible for complications related to AAS misuse. Considering the age-independent stiffening of major arteries and the predictive power of an increase in PWV and cIMT, the long-term users of AAS are at increased risk of severe cardiovascular events.


Subject(s)
Carotid Intima-Media Thickness , Pulse Wave Analysis , Animals , Carotid Arteries/diagnostic imaging , Elasticity , Female , Male , Mice , Testosterone
2.
Scand J Rheumatol ; 51(3): 186-195, 2022 05.
Article in English | MEDLINE | ID: mdl-34132621

ABSTRACT

OBJECTIVES: Inflammatory joint disease (IJD) is associated with an increased risk of developing cardiovascular disease (CVD). Arterial stiffness is both a risk factor and a surrogate marker for CVD. This study aims to compare arterial stiffness across patients with rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis, and, by extension, to explore the relationship between arterial stiffness and the estimated CVD risk by the Systematic COronary Risk Evaluation (SCORE) algorithm. METHOD: During the study period, from April 2017 to June 2018, 196 patients with IJD visited the Preventive Cardio-Rheuma Clinic in Oslo, Norway. A CVD risk stratification was performed, including the assessment of traditional risk factors and the measurement of arterial stiffness. RESULTS: Thirty-six patients (18.4%) had elevated aortic pulse wave velocity (aPWV) (≥ 10 m/s). After adjustment for age and heart rate, arterial stiffness was comparable across the IJD entities (p = 0.69). Associated factors, revealed by regression analysis, were age, blood pressure, heart rate, presence of carotid plaques, establis hed CVD, non-steroidal anti-inflammatory drugs, and statin use. Furthermore, aPWV was positively correlated with estimated CVD risk (r = 0.7, p < 0.001) and patients with a very high predicted CVD risk (SCORE ≥ 10%) had significantly higher aPWV than patients at lower CVD risk (9.2 vs 7.5 m/s, p < 0.001). CONCLUSION: The degree of arterial stiffness was comparable across the IJD entities and was highly associated with the estimated CVD risk. Our findings support the need for an increased focus on prevention of CVD in all patients with IJD.


Subject(s)
Arthritis, Rheumatoid , Cardiovascular Diseases , Vascular Stiffness , Arthritis, Rheumatoid/drug therapy , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/etiology , Humans , Pulse Wave Analysis/adverse effects , Risk Factors
3.
J Electr Bioimpedance ; 12(1): 169-177, 2021 Jan.
Article in English | MEDLINE | ID: mdl-35111272

ABSTRACT

The leading cause of health loss and deaths worldwide are cardiovascular diseases. A predictor of cardiovascular diseases and events is the arterial stiffness. The pulse wave velocity (PWV) can be used to estimate arterial stiffness non-invasively. The tonometer is considered as the gold standard for measuring PWV. This approach requires manual probe fixation above the artery and depends on the skills of the operator. Electrical impedance plethysmography (IPG) is an interesting alternative using skin surface sensing electrodes, that is miniaturizable, cost-effective and allows measurement of deeper arteries. The aim of this pilot study was to explore if IPG can be a suitable technique to measure pulse wave velocity in legs as an alternative for the tonometer technique. The PWV was estimated by differences in the ECG-gated pulse arrival times (PAT) at the a. femoralis, a. popliteal, a. tibialis dorsalis and a. dorsalis pedis in nine healthy young adults using IPG and the SphygmoCor tonometer as a reference. The estimated PWV results from bioimpedance and the tonometer were fairly in agreement, and the beat-to-beat variability in PAT was similar. This pilot study indicates that the use of IPG may be a good alternative for estimating PWV in the legs.

4.
Physiol Meas ; 41(4): 044008, 2020 05 07.
Article in English | MEDLINE | ID: mdl-32235072

ABSTRACT

OBJECTIVE: Storage at temperatures as low as -80 °C and below (cryopreservation) is considered a method for long-term preservation of cells and tissues, and especially blood vessel segments, which are to be used for clinical operations such as transplantation. However, the freezing and thawing processes themselves can induce injuries to the cells and tissue by damaging the structure and consequently functionality of the cryopreserved tissue. In addition, the level of damage is dependent on the rate of cooling and warming used during the freezing-thawing process. Current methods for monitoring the viability and integrity of cells and tissues after going through the freezing-thawing cycle are usually invasive and destructive to the cells and tissues. Therefore, employing monitoring methods which are not destructive to the cryopreserved tissues, such as bioimpedance measurement techniques, is necessary. In this study we aimed to design a bioimpedance measurement setup to detect changes in venous segments after freezing-thawing cycles in a noninvasive manner. APPROACH: A bioimpedance spectroscopy measurement technique with a two-electrode setup was employed to monitor ovine jugular vein segments after each cycle during a process of seven freezing-thawing cycles. MAIN RESULTS: The results demonstrated changes in the impedance spectra of the measured venous segments after each freezing-thawing cycle. SIGNIFICANCE: This indicates that bioimpedance spectroscopy has the potential to be developed into a novel method for non-invasive and non-destructive monitoring of the viability of complex tissue after cryopreservation.


Subject(s)
Cryopreservation , Dielectric Spectroscopy/instrumentation , Veins , Electrodes , Humans , Quality Control
5.
J Electr Bioimpedance ; 9(1): 142-158, 2018 Jan.
Article in English | MEDLINE | ID: mdl-33584930

ABSTRACT

Rapid development in the field of tissue engineering necessitates implementation of monitoring methods for evaluation of the viability and characteristics of the cell cultures in a real-time, non-invasive and non-destructive manner. Current monitoring techniques are mainly histological and require labeling and involve destructive tests to characterize cell cultures. Bioimpedance measurement technique which benefits from measurement of electrical properties of the biological tissues, offers a non-invasive, label-free and real-time solution for monitoring tissue engineered constructs. This review outlines the fundamentals of bioimpedance, as well as electrical properties of the biological tissues, different types of cell culture constructs and possible electrode configuration set ups for performing bioimpedance measurements on these cell cultures. In addition, various bioimpedance measurement techniques and their applications in the field of tissue engineering are discussed.

6.
Int J Cardiol ; 223: 331-336, 2016 Nov 15.
Article in English | MEDLINE | ID: mdl-27543704

ABSTRACT

OBJECTIVES: Cardiovascular disease (CVD) risk calculators developed for the general population have been shown to inaccurately predict CVD events in patients with inflammatory joint disease (IJD). European guidelines for CVD prevention recognize the presence of carotid plaques (CP) as a very high CVD risk factor, equivalent of coronary artery disease. Patients with IJD have a high prevalence of CP. We evaluated if CP resulted in reclassification of patients with IJD into a more appropriate CVD risk class and recommended lipid lowering treatment. METHODS: CVD risk evaluation was performed in patients with IJD using SCORE and ACC/AHA risk calculators to predict CVD events. RESULTS: Of the 335 IJD patients evaluated (including rheumatoid arthritis n=201, ankylosing spondylitis n=85 and psoriatic arthritis n=49), 183 and 159 IJD patients had a calculated CVD risk by SCORE and ACC/AHA <5%, indicating no need of lipid lowering treatment (LLT). However, of patients with low to moderate risk calculated by SCORE and ACC/AHA, 67 (36.6%) and 48 (30.2%) had CP and should according to guidelines receive intensive LLT. For patients with high risk, in the LLT considered group, 54.9% and 58.1% were reclassified to correct treatment when adding information on the presence of CP. Our results reveal a considerable reclassification into correct CVD risk category when adding CP in female patients. CONCLUSION: The high frequency of asymptomatic atherosclerosis in patients with IJD has a notable impact on CVD risk stratification. Identification of CP will reclassify patients into recommended CVD preventive treatment group, which may be clinically important.


Subject(s)
Cardiovascular Diseases/epidemiology , Joint Diseases/complications , Risk Assessment/methods , Adult , Aged , Cardiovascular Diseases/etiology , Female , Follow-Up Studies , Humans , Incidence , Male , Middle Aged , Norway/epidemiology , Retrospective Studies , Risk Factors
7.
Int J Sports Med ; 36(14): 1170-6, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26509381

ABSTRACT

We wanted to explore whether change in LA (left atrium) size would influence LA function, or increase regurgitation in the atrioventricular valves. 595 male elite football players and 47 non-athletic controls were included. End-systolic LA volume and RA area and end-diastolic LV volume and RV area were measured by 2-dimensional (2D) echocardiography Pulsed and colour Doppler were used to estimate tricuspid and mitral regurgitations. 2D longitudinal strain of the 50 football players with the largest LA volumes were compared with the 50 players with the smallest LA volumes. The LA volumes in some athletes with large atria were more than tripled, compared to athletes with small atria. 2D strain however, could not reveal any impairment of LA function in the players with the largest atria, compared to those with the smallest LA. Tricuspid valve regurgitation was found in 343 (58%) of the athletes, compared to 17 (36%) of the controls (p<0.01), while mitral regurgitation was found in 116 (20%) football players and 7 (15%) controls (NS). Furthermore, the RA area was significantly larger in athletes with tricuspid regurgitation compared to athletes without. The present study demonstrated a huge variation in atrial size between the athletes. This variation, however, had no impact on LA function. Tricuspid regurgitation was significantly more prevalent among the athletes, than among the controls.


Subject(s)
Heart Atria/anatomy & histology , Soccer/physiology , Ventricular Function/physiology , Adaptation, Physiological , Adolescent , Adult , Echocardiography, Doppler , Heart Atria/diagnostic imaging , Hemodynamics , Humans , Male , Mitral Valve Insufficiency/physiopathology , Organ Size , Reference Values , Regression Analysis , Tricuspid Valve Insufficiency/physiopathology , Young Adult
8.
Arthritis Rheumatol ; 67(7): 1718-28, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25778850

ABSTRACT

OBJECTIVE: Patients with rheumatoid arthritis (RA) and carotid artery plaques have an increased risk of acute coronary syndromes. Statin treatment with the goal of achieving a low-density lipoprotein (LDL) cholesterol level of ≤1.8 mmoles/liter (≤70 mg/dl) is recommended for individuals in the general population who have carotid plaques. The aim of the ROsuvastatin in Rheumatoid Arthritis, Ankylosing Spondylitis and other inflammatory joint diseases (RORA-AS) study was to evaluate the effect of 18 months of intensive lipid-lowering treatment with rosuvastatin with regard to change in carotid plaque height. METHODS: Eighty-six patients (60.5% of whom were female) with carotid plaques and inflammatory joint disease (55 with RA, 21 with AS, and 10 with psoriatic arthritis) were treated with rosuvastatin to obtain the LDL cholesterol goal. Carotid plaque height was evaluated by B-mode ultrasonography. RESULTS: The mean ± SD age of the patients was 60.8 ± 8.5 years, and the median compliance with rosuvastatin treatment was 97.9% (interquartile range [IQR] 96.0-99.4). At baseline, the median number and height of the carotid plaques were 1.0 (range 1-8) and 1.80 mm (IQR 1.60-2.10), respectively. The mean ± SD change in carotid plaque height after 18 months of treatment with rosuvastatin was -0.19 ± 0.35 mm (P < 0.0001). The mean ± SD baseline LDL cholesterol level was 4.0 ± 0.9 mmoles/liter (154.7 ± 34.8 mg/dl), and the mean reduction in the LDL cholesterol level was -2.3 mmoles/liter (95% confidence interval [95% CI] -2.48, -2.15) (-88.9 mg/dl [95% CI -95.9, -83.1]). The mean ± SD LDL cholesterol level during the 18 months of rosuvastatin treatment was 1.7 ± 0.4 mmoles/liter (area under the curve). After adjustment for age/sex/blood pressure, no linear relationship between a reduction in carotid plaque height and the level of LDL cholesterol exposure during the study period was observed. Attainment of the LDL cholesterol goal of ≤1.8 mmoles/liter (≤70 mg/dl) or the amount of change in the LDL cholesterol level during the study period did not influence the degree of carotid plaque height reduction. CONCLUSION: Intensive lipid-lowering treatment with rosuvastatin induced atherosclerotic regression and reduced the LDL cholesterol level significantly in patients with inflammatory joint disease.


Subject(s)
Arthritis, Psoriatic/complications , Arthritis, Rheumatoid/complications , Carotid Stenosis/prevention & control , Fluorobenzenes/therapeutic use , Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Pyrimidines/therapeutic use , Spondylitis, Ankylosing/complications , Sulfonamides/therapeutic use , Acute Coronary Syndrome/epidemiology , Aged , Carotid Stenosis/blood , Carotid Stenosis/diagnostic imaging , Cholesterol, LDL/blood , Female , Humans , Logistic Models , Male , Middle Aged , Prospective Studies , Risk Factors , Rosuvastatin Calcium , Treatment Outcome , Ultrasonography, Interventional
9.
Ann Rheum Dis ; 74(8): 1544-50, 2015 Aug.
Article in English | MEDLINE | ID: mdl-24699940

ABSTRACT

OBJECTIVES: There is a lipid paradox in rheumatoid arthritis describing that despite low lipids related to systemic inflammation, there is an increased cardiovascular (CV) risk. Our aim was to evaluate if baseline lipid levels or baseline systemic inflammation were associated with the statin dose sufficient to achieve lipid targets in patients with inflammatory joint diseases. METHODS: In this longitudinal, short-term follow-up observational report, we evaluated 197 patients who did and 36 patients who did not reach the recommended low density lipoprotein cholesterol (LDL-c) target. The patients were, after CV risk evaluation, classified to either primary or secondary CV prevention with lipid lowering treatment (LLT). LLT was initiated with statins and adjusted until at least two lipid targets were achieved. Intensive LLT was defined as rosuvastatin ≥20 mg, atorvastatin and simvastatin at the highest dose (80 mg), and conventional LLT were defined as all lower doses. RESULTS: In an independent sample t test, systemic inflammation or lipid levels at baseline were not associated with the statin dose (intensive or conventional) needed to achieve recommended LDL-c target (C reactive protein/erythrocyte sedimentation rate: p=0.10 and p=0.11, and LDL-c/total cholesterol: p=0.17 and p=0.34, respectively). The baseline inflammatory status and lipid levels in patients who did and did not obtain LDL-c goal were comparable (C reactive protein/erythrocyte sedimentation rate: p=0.32 and p=0.64, and LDL-c/total cholesterol: p=0.20 and p=0.83, respectively). CONCLUSIONS: Systemic inflammation or lipid levels did not influence the intensity of statin treatment needed to obtain guideline recommended lipid targets in CV prevention. Whether the background inflammation in patients with inflammatory joint diseases over time influences the CV risk reduction related to statins is yet unknown.


Subject(s)
Arthritis, Psoriatic/blood , Arthritis, Rheumatoid/blood , Cardiovascular Diseases/blood , Cholesterol, LDL/blood , Cholesterol, LDL/drug effects , Hydroxymethylglutaryl-CoA Reductase Inhibitors/administration & dosage , Spondylitis, Ankylosing/blood , Aged , Arthritis, Rheumatoid/epidemiology , Atorvastatin/administration & dosage , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/prevention & control , Comorbidity , Female , Humans , Hyperlipidemias/epidemiology , Male , Middle Aged , Rosuvastatin Calcium/administration & dosage , Simvastatin/administration & dosage , Spondylitis, Ankylosing/epidemiology
10.
Scand J Med Sci Sports ; 24(5): e372-80, 2014 Oct.
Article in English | MEDLINE | ID: mdl-24472028

ABSTRACT

This investigation explores the cardiac four-chamber remodeling response to training in male players in Norwegian professional football league, and ethnicity as determinants in the development of athlete's heart. Standard 2D echocardiographic examination and analysis of all four cavities were performed in 504 football players of Caucasian origin, 49 of African origin, and 47 matched Caucasian controls (<3 h training /week). All results were indexed to body surface area (BSA). Most athletes exhibited BSA-indexed values within normal ranges. Left ventricle (LV) mass was equally enlarged in both groups of athletes, but LV relative wall thickness and right ventricular (RV) relative wall thickness were increased in Africans compared with Caucasian athletes (0.37 ± 0.06 vs 0.33 ± 0.06 and 0.25 ± 0.06 vs 0.22 ± 0.04, respectively). Both LV and RV were smaller in Africans than in Caucasian athletes (67.8 ± 12.0 ml/m(2) vs 73.6 ± 13.2 ml/m(2) and 12.8 ± 2.1 vs 13.7 ± 2.4 cm(2) /m(2) , respectively, both P < 0.05), while left and right atria increased similarly. This first large-scale echocardiographic survey of elite football players in a Scandinavian league suggests use of BSA-indexed upper normal limits for both LV and RV in athletes. African athletes had significantly more concentric remodeled LV and RV than the Caucasian athletes.


Subject(s)
Atrial Remodeling , Black People , Physical Conditioning, Human/physiology , Soccer/physiology , Ventricular Remodeling , White People , Adult , Body Surface Area , Cross-Sectional Studies , Heart Atria/diagnostic imaging , Heart Ventricles/diagnostic imaging , Humans , Male , Norway , Ultrasonography , Young Adult
11.
Angiology ; 62(4): 301-5, 2011 May.
Article in English | MEDLINE | ID: mdl-21474466

ABSTRACT

Elevated plasma levels of vascular inflammatory markers have been reported in patients with peripheral arterial disease (PAD). We assessed the effect of supervised exercise training (ET) on vascular inflammation, hypothesizing that ET reduces plasma levels of the endothelial adhesion molecules E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-I (VCAM-I). Twenty-nine patients with PAD underwent a supervised ET program for 8 weeks. Before and after ET, walking distances (pain-free, PWD; maximal, MWD) were determined by a standard treadmill test. Plasma levels of E-selectin and ICAM-I were significantly reduced (E-selectin: 45.5-40.4 ng/mL, P = .013); ICAM-I: 342.0-298.0 ng/mL, P = .016). VCAM-1 levels were unchanged. Walking distances increased significantly (PWD: median 77-150 m, P < .001; MWD: median 306-535 m, P < .001). In conclusion, 8 weeks of ET in patients with PAD reduces plasma levels of the specific endothelium-derived inflammatory markers E-selectin and ICAM-I.


Subject(s)
E-Selectin/blood , Exercise Therapy , Intercellular Adhesion Molecule-1/blood , Peripheral Vascular Diseases/blood , Peripheral Vascular Diseases/therapy , Aged , Exercise Test , Female , Humans , Male , Middle Aged , Peripheral Vascular Diseases/physiopathology , Statistics, Nonparametric , Walking/physiology
12.
Eur J Vasc Endovasc Surg ; 33(1): 20-5, 2007 Jan.
Article in English | MEDLINE | ID: mdl-16934498

ABSTRACT

OBJECTIVES: The purpose of this study was to compare the circulatory responses to walking in patients with peripheral atherosclerotic disease (PAD) and healthy controls. METHODS: The participants were eleven patients with diagnosed PAD, and a control group of six healthy age-matched adults. Blood pressure, heart rate (HR), and acral skin perfusion were recorded continuously before, during and after a walking exercise on a treadmill. RESULTS: The patients walked to maximum claudication distance (MCD) on a treadmill, median walking distance 103 (34-223) metres [median (range)], at 3.3 (1.0-4.5) km/h. There was a steep increase in HR and mean arterial pressure (MAP) while the patients were walking. At claudication the median rise in MAP was 46.6 (10.3-61.3) mmHg, systolic blood pressure (SP) increased by 84.9 (31.4-124.9) mmHg, and diastolic blood pressure (DP) by 21.7 (-2.1-31.7) mmHg. HR increased by 34.9 (12.9-48.1) beats/min. The control group walked for 5 minutes at 3.2 (3.0-3.3) km/h. In the control group the blood pressure initially increased moderately but stabilised thereafter. Median rise in MAP during walking was 8.5 (5.6-14.6) mmHg, SP increased by 30.9 (6.6-41.5) mmHg, and DP was reduced by -1.4 (-5.4-1.5) mmHg. HR increased by 27.1 (18.8-34.9) beats/min. We found no significant differences in acral skin perfusion during walking exercise between the patients and control group. CONCLUSIONS: In patients with PAD, blood pressure increased continuously and significantly when walking to MCD (dynamic exercise). The level of increase in blood pressure was similar to that caused in response to isometric exercise.


Subject(s)
Atherosclerosis/physiopathology , Blood Pressure , Intermittent Claudication/physiopathology , Leg/blood supply , Peripheral Vascular Diseases/physiopathology , Walking , Aged , Aged, 80 and over , Atherosclerosis/complications , Case-Control Studies , Female , Heart Rate , Humans , Intermittent Claudication/etiology , Male , Middle Aged , Peripheral Vascular Diseases/complications , Regional Blood Flow , Skin/blood supply , Time Factors
13.
Acta Physiol Scand ; 174(2): 101-8, 2002 Feb.
Article in English | MEDLINE | ID: mdl-11860371

ABSTRACT

It is well established that consumption of a meal releases a gradually developing and quite marked increase in blood flow to the gastrointestinal organs and a similar and simultaneous increase in cardiac output (CO). It is not known through which mechanism the pumping of the heart adjusts so accurately to the gastrointestinal flow increase. We have approached this problem by serving a standardized, mixed meal to five patients with recently transplanted and thus denervated hearts and to five sex- and age-matched controls. Pre- and postprandial levels of CO and blood flow in the superior mesenteric artery (SMA) were recorded with Doppler ultrasound technique. The patients with transplanted hearts had significantly higher preprandial levels of heart rate (HR) and CO than the controls. With a timing similar to that seen in the controls did all five patients develop considerable and synchronous postprandial increases in superior mesenteric arterial flow and in CO. Increases in superior mesenteric arterial flow were significantly greater than the controls. Also, COs, high even before meals were given, increased further and to the same relative extent as in the control persons. The marked postprandial increase in CO, probably secondary to the increase in intestinal blood flow, could hardly come about through any sort of nervous reflex to the recently transplanted and denervated hearts. It appears more likely that a humoral connection of some sort exists between the two circulatory events.


Subject(s)
Cardiac Output/physiology , Eating/physiology , Heart Transplantation , Splanchnic Circulation/physiology , Adult , Aged , Blood Pressure/physiology , Denervation , Female , Heart/innervation , Heart Rate/physiology , Humans , Male , Mesenteric Artery, Superior/physiology , Middle Aged , Time Factors
14.
Am J Physiol Regul Integr Comp Physiol ; 281(1): R213-21, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11404296

ABSTRACT

The hypothesis tested was that there are significant transient changes in the cardiovascular variables after rapid onset and release of mild lower body negative pressure (LBNP, -20 mmHg), even in experimental situations where there is no detectable change in steady-state values. Twelve subjects participated in the study. Heart rate, stroke volume (SV), cardiac output, mean arterial pressure (MAP), total peripheral resistance (TPR), acral and nonacral skin blood flow, and blood flow velocity in the brachial artery were continuously recorded during the pre-LBNP period (0-120 s), during LBNP (120-420 s), and during the post-LBNP period (420-600 s). The main finding was that MAP is transiently but strongly affected by rapid changes in LBNP as small as -20 mmHg. There was also a characteristic asymmetry in cardiovascular responses to the onset and release of LBNP, particularly in the responses in SV. The transient changes in MAP indicate that the neural responses that affect TPR are not fast enough to compensate for the rapid changes in LBNP. In this case, the arterial baroreceptors will be activated as well as the low-pressure baroreceptors that sense central venous pressure. This must be taken into consideration in future discussions of the results of LBNP protocols.


Subject(s)
Blood Pressure/physiology , Heart Rate/physiology , Lower Body Negative Pressure , Adult , Brachial Artery/physiology , Female , Humans , Male , Skin/blood supply , Stroke Volume/physiology , Vascular Resistance/physiology
15.
Am J Physiol ; 276(3): R731-7, 1999 03.
Article in English | MEDLINE | ID: mdl-10070133

ABSTRACT

We have investigated the effect of severe local cooling on the vasomotor activity of the arteriovenous anastomoses (AVAs) and other finger vessels. The right third finger was subjected to local cooling (3 degrees C) for 30-45 min in 21 healthy, thermoneutral subjects. Blood velocity in the third finger arteries of both hands was simultaneously recorded using ultrasound Doppler, and skin temperature and laser-Doppler flux from the pulp of the cooled finger were also recorded. The results demonstrate that the initial cold-induced vasoconstriction during severe local cooling involves constriction of the AVAs as well as the two main arteries supplying this finger. During cold-induced vasodilatation (CIVD), the maximum velocity values were not significantly different from those before cooling. Furthermore, the velocity fluctuations in the cooled finger were in most subjects found to be synchronous with the velocity fluctuations in the control finger. This indicates that the large blood flow to the finger and the high skin temperature during CIVD are caused by relaxation of the smooth muscle cells of the AVAs.


Subject(s)
Cold Temperature , Fingers/blood supply , Vasodilation/physiology , Adult , Arteries/diagnostic imaging , Arteries/physiology , Arteriovenous Anastomosis/physiology , Blood Flow Velocity/physiology , Female , Fingers/diagnostic imaging , Humans , Laser-Doppler Flowmetry , Male , Reference Values , Regional Blood Flow/physiology , Skin Temperature/physiology , Ultrasonography , Vasomotor System/physiology
SELECTION OF CITATIONS
SEARCH DETAIL
...