Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity

Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia.

Relationship between deep venous thrombosis and inflammatory cytokines in postoperative patients with malignant abdominal tumors

Deep venous thrombosis (DVT) is a common surgical complication in cancer patients and evidence that inflammation plays a role in the occurrence of DVT is increasing. We studied a population of cancer patients with abdominal malignancies with the aim of investigating whether the levels of circulating inflammatory cytokines were associated with postoperative DVT, and to determine the levels in DVT diagnoses. The serum levels of C-reactive protein (CRP), interleukins (IL)-6 and IL-10, nuclear transcription factor-κB (NF-κB) and E-selectin (E-Sel) were determined in 120 individuals, who were divided into 3 groups: healthy controls, patients with and patients without DVT after surgery for an abdominal malignancy. Data were analyzed by ANOVA, Dunnet's T3 test, chi-square test, and univariate and multivariate logistic regression as needed. The CRP, IL-6, NF-κB, and E-Sel levels in patients with DVT were significantly higher than those in the other groups (P<0.05). The IL-10 level was higher in patients with DVT than in controls but lower than in patients without DVT. Univariate analysis revealed that CRP, IL-6, NF-κB, and E-Sel were statistically associated with the risk of DVT (OR=1.98, P=0.002; OR=1.17, P=0.000; OR=1.03, P=0.042; and OR=1.38, P=0.003; respectively), whereas IL-10 had a protective effect (OR=0.94, P=0.011). Multivariate analysis showed that E-Sel was an independent risk factor (OR=1.41, P=0.000). Thus, this study indicated that an increased serum level of E-Sel was associated with increased DVT risk in postoperative patients with abdominal malignancy, indicating that E-Sel may be a useful predictor of diagnosis of DVT.

Morphologic evaluation of ruptured abdominal aortic aneurysm by 3D modeling

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Abdominal aortic aneurysm follow-up after endovascular repair in a canine model with non-invasive vascular elastography

Le traitement chirurgical des anévrismes de l'aorte abdominale est de plus en plus remplacé par la réparation endovasculaire de l’anévrisme (« endovascular aneurysm repair », EVAR) en utilisant des endoprothèses (« stent-grafts », SGs). Cependant, l'efficacité de cette approche moins invasive est compromise par l'incidence de l'écoulement persistant dans l'anévrisme, appelé endofuites menant à une rupture d'anévrisme si elle n'est pas détectée. Par conséquent, une surveillance de longue durée par tomodensitométrie sur une base annuelle est nécessaire ce qui augmente le coût de la procédure EVAR, exposant le patient à un rayonnement ionisants et un agent de contraste néphrotoxique. Le mécanisme de rupture d'anévrisme secondaire à l'endofuite est lié à une pression du sac de l'anévrisme proche de la pression systémique. Il existe une relation entre la contraction ou l'expansion du sac et la pressurisation du sac. La pressurisation résiduelle de l'anévrisme aortique abdominale va induire une pulsation et une circulation sanguine à l'intérieur du sac empêchant ainsi la thrombose du sac et la guérison de l'anévrisme. L'élastographie vasculaire non-invasive (« non-invasive vascular elastography », NIVE) utilisant le « Lagrangian Speckle Model Estimator » (LSME) peut devenir une technique d'imagerie complémentaire pour le suivi des anévrismes après réparation endovasculaire. NIVE a la capacité de fournir des informations importantes sur l'organisation d'un thrombus dans le sac de l'anévrisme et sur la détection des endofuites. La caractérisation de l'organisation d'un thrombus n'a pas été possible dans une étude NIVE précédente. Une limitation de cette étude était l'absence d'examen tomodensitométrique comme étalon-or pour le diagnostic d'endofuites. Nous avons cherché à appliquer et optimiser la technique NIVE pour le suivi des anévrismes de l'aorte abdominale (AAA) après EVAR avec endoprothèse dans un modèle canin dans le but de détecter et caractériser les endofuites et l'organisation du thrombus. Des SGs ont été implantés dans un groupe de 18 chiens avec un anévrisme créé dans l'aorte abdominale. Des endofuites de type I ont été créés dans 4 anévrismes, de type II dans 13 anévrismes tandis qu’un anévrisme n’avait aucune endofuite. L'échographie Doppler (« Doppler ultrasound », DUS) et les examens NIVE ont été réalisés avant puis à 1 semaine, 1 mois, 3 mois et 6 mois après l’EVAR. Une angiographie, une tomodensitométrie et des coupes macroscopiques ont été réalisées au moment du sacrifice. Les valeurs de contrainte ont été calculées en utilisant l`algorithme LSME. Les régions d'endofuite, de thrombus frais (non organisé) et de thrombus solide (organisé) ont été identifiées et segmentées en comparant les résultats de la tomodensitométrie et de l’étude macroscopique. Les valeurs de contrainte dans les zones avec endofuite, thrombus frais et organisé ont été comparées. Les valeurs de contrainte étaient significativement différentes entre les zones d'endofuites, les zones de thrombus frais ou organisé et entre les zones de thrombus frais et organisé. Toutes les endofuites ont été clairement caractérisées par les examens d'élastographie. Aucune corrélation n'a été trouvée entre les valeurs de contrainte et le type d'endofuite, la pression de sac, la taille des endofuites et la taille de l'anévrisme.

Implicaciones clínicas y quirúrgicas de las variaciones anatómicas vasculares del riñón

Introducción: Conocer y diagnosticar las variaciones más frecuentes de la vasculatura renal es de gran importancia para la planificación de la nefrectomía laparoscópica en el donante y para la reconstrucción vascular en el trasplante renal. De igual forma, considerar las variaciones vasculares −especialmente las del sistema venoso− es indispensable en reconstrucción vascular debido a la gran proporción de variaciones venosas asociadas a aneurismas de la aorta abdominal; además, es ideal en el estudio de condiciones clínicas tales como el síndrome de congestión pélvica y la hematuria. Metodología: Se trata de una revisión de la bibliografía sobre la proporción, diagnóstico, procedimientos quirúrgicos y síndromes clínicos asociados a las variaciones de la vasculatura renal, basada en el material encontrado con la siguiente estrategia de búsqueda: “Renal Artery/abnormalities”[Mesh] OR Renal Veins/abnormalities”[Mesh] AND “surgery”[Mesh] OR “transplantation”[Mesh] OR “radiography”[Mesh] “Kidney Pelvis/abnormalities”[Mesh] AND “Kidney Pelvis/blood supply”[Mesh]. Esta estrategia se modificó de acuerdo con las bases de datos: MEDLINE/PubMed, MEDLINE OVID, SCIENCEDIRECT, HINARI y LILACS. Desarrollo: Se revisó el origen y los tipos más frecuentes de variaciones de la vasculatura renal. Se investigó sobre las implicaciones quirúrgicas y los síndromes clínicos asociados.

Hypoxic modulation of ca(2+) signaling in human venous and arterial endothelial cells

Our understanding of vascular endothelial cell physiology is based on studies of endothelial cells cultured from various vascular beds of different species for varying periods of time. Systematic analysis of the properties of endothelial cells from different parts of the vasculature is lacking. Here, we compare Ca(2+) homeostasis in primary cultures of endothelial cells from human internal mammary artery and saphenous vein and how this is modified by hypoxia, an inevitable consequence of bypass grafting (2.5% O(2), 24 h). Basal [Ca(2+)]( i ) and store depletion-mediated Ca(2+) entry were significantly different between the two cell types, yet agonist (ATP)-mediated mobilization from endoplasmic reticulum stores was similar. Hypoxia potentiated agonist-evoked responses in arterial, but not venous, cells but augmented store depletion-mediated Ca(2+) entry only in venous cells. Clearly, Ca(2+) signaling and its remodeling by hypoxia are strikingly different in arterial vs. venous endothelial cells. Our data have important implications for the interpretation of data obtained from endothelial cells of varying sources.

Microalbuminuria is associated with impaired arterial and venous endothelium-dependent vasodilation in patients with Type 2 diabetes

Background: Microalbuminuria in Type 2 diabetes is associated with arterial endothelial dysfunction, but the venous bed was never evaluated. Aim: To study the endothelial function in the venous and arterial bed in patients with Type 2 diabetes with normoalbuminuria or microalbuminuria. Material and methods: We evaluated 28 patients with Type 2 diabetes, glycated hemoglobin (Hbak(1c)) <7.5%, who were classified as normo- (albuminuria <30 mg/24 h; no.=16) or microalbuminuric (albuminuria 30-300 mg/24 h; no.=12). Venous and arterial endothelial function were assessed by the dorsal hand vein technique (venodilation by acetylcholine) and brachial artery flow-mediated vasodilation, respectively. Results: Patients were normotensive (systolic arterial pressure: 131.1 +/- 10.6 mmHg) and on good metabolic control (HbA(1c): 6.6 +/- 0.6%). Microalbuminuric patients presented impaired venous (32.9 +/- 17.4 vs 59.3 +/- 26.5%; p=0.004) and arterial vasodilation (1.8 +/- 0.9 vs 5.1 +/- 2.4; p<0.001), as compared to normoalbuminuric patients. There was a negative correlation between acetylcholine-induced venodilation and albuminuria (r=-0.62; p<0.001) and HbA(1c) (r=-0.41; p=0.032). The same was observed between flow-mediated arterial vasodilation and albuminuria (r=-0.49; p=0.007) and HbA(1c) (r=-0.44; p=0.019). Venous and arterial vasodilation was positively correlated (r=0.50; p=0.007). Conclusions: Both venous and arterial endothelial function are impaired in Type 2 microalbuminuric diabetics, in spite of good metabolic control, suggesting that other factors are involved in its pathogenesis. (J. Endocrinol. Invest. 33: 696-700, 2010) (C) 2010, Editrice Kurtis

Reduced venous endothelial responsiveness after oral lipid overload in healthy volunteers

The aim of this study was to investigate endothelial venous function, mflammatory markers, and systemic oxidative stress after an oral lipid overload (OLO). We studied 18 healthy adults (9 men; age, 29.2 +/- 0.9 years; body mass index, 22.3 +/- 0.4 kg/m(2)). Blood samples were collected in the fasting state and 3, 4, and 5 hour after the OLO (1000 kcal, 58% fat) for metabolic variables, oxidative stress, inflammatory markers, adiponectin, and resistin. Changes in vein diameter to phenylephrine, acetylcholine, and sodium nitroprusside (dorsal hand vein technique) were measured before and after the OLO. Oral lipid overload increased triglycerides (61 +/- 6 vs 134 +/- 17 mg/dL, P <.001), insulin (7.2 +/- 0.8 vs 10.7 +/- 1.3 mu U/mL, P <.05), and resistin (5.38 +/- 0.5 vs 6.81 +/- 0.7 ng/mL, P <.05) and reduced antioxidant capacity (plasma total antioxidant capacity: 186.7 +/- 56 vs 161.8 +/- 50 U Trolox per microliter plasma, P <.01), vascular reactivity (171.3 +/- 85 vs 894.4 +/- 301 ng/mL, P <.001), and maximum acetylcholine venodilation (105.9% +/- 9% vs 61.0% +/- 7%, P <.05). No changes were observed for sodium nitroprusside. Post-OLO triglycerides were positively correlated with phenylephrine dose (rho = 0.38, P <.05) and resistin (rho = 0.43, P <.01) and negatively correlated with the maximum acetylcholine venodilation (rho = -0.36, P <.05). In conclusion, an OLO impaired venoconstriction responsiveness in healthy subjects, probably because of a reduction in the antioxidant capacity. (C) 2008 Elsevier Inc. All rights reserved.

Androgenicity and venous endothelial function in post-menopausal women

Background: Endothelial dysfunction is one of the early signs of cardiovascular damage. High androgen levels have been related to inflammatory endothelial markers in pre- and post-menopausal women. Aim: This cross-sectional study aimed at investigating whether free androgen index (FAI) [estimated by dividing total testosterone (nmol/l) by SHBG (nmol/l) x 100] is related to endothelial function during post-menopause. Subjects and methods: Twenty-six post-menopausal women were assessed with the dorsal hand vein compliance technique. Acetylcholine (Ach) and sodium nitroprusside (SNP) dose-response curves were constructed to test endothelium-dependent and independent relaxation, respectively. Results: Mean age was 54 yr ( 4) and median time since menopause was 6 yr (interquartile range: 3-9). Patients were stratified according to FAI levels into two groups: FAI greater than or less than the group median of 2.5. Waist-to-hip ratio (WHR) was significantly higher in the group with FAI>2.5, as well as median dose of Ach for maximal vasodilation [720 (360-3600) ng/min with FAI>2.5 vs 36 (0.36-360) ng/min with FAI <= 2.5; p=0.005]. Maximal vasodilation with SNP was similar in both groups. Positive correlations were observed between Ach doses and maximal vasodilation and FAI (r=0.473, p=0.015), waist (r=0.510, p= 0.011), and WHR (r=0.479, p=0.021). SHBG was negatively correlated with Ach doses (rs=-0.400, p=0.043). Conclusions: This study suggests that FAI, even within normal limits, is related to early changes in endothelial function in healthy post-menopausal women. Longitudinal studies are required to determine the clinical relevance of these findings. (J. Endocrinol. Invest. 33: 239-243, 2010) (C) 2010, Editrice Kurtis

Att leva med diagnosen Abdominellt Aorta Aneurysm : -en litteraturstudie om upplevelser kring sjukdom och omvårdnad ur ett patientperspektiv

Bakgrund: Över 150 000 människor i Sverige behandlas årligen för hjärt- och kärlsjukdom. En vanlig form är ateroskleros, åderförkalkning. Av alla de som idag avlider på grund av annan orsak än naturligt åldrande, gör de flesta det av komplikationer till aterosklerossjukdom. En av dessa komplikationer är aortaanerysm, mera känt som ”pulsåderbråck”. Det vanligast förekommande är abdominellt aortaanerysm, bukaortaaneurysm. Syfte: Syftet med denna studie var att belysa livssituationer, livskvalitet och omvårdnadsbehov hos patienter med diagnosen AAA samt att visa på omvårdnadsåtgärder som främjar hälsa hos patienter med denna diagnos. Metod: En litteraturgranskning gjordes i databaserna PubMed, Chinal och Psychinfo samt Högskolan Dalarnas sökmotor Elin. Artiklarna valdes ut efter relevans till syftet. Dess kvalitet värderades med hjälp av granskningsmallar. Fyra kvalitativa och 16 kvantitativa ansatser ingick i studien. Resultat: Det framkom att HRQoL hos patienter som fick diagnosen AAA försämrades signifikant perioperativt. Oro och rädsla samt känslor av overklighet, nära döden upplevelser och existentiella frågor var vanligt perioperativt. Ingen påvisbar skillnad före och efter screening i HRQoL eller upplevd hälsa iakttogs. Mer information kring exempelvis sexualitet perioperativt kunde lindra oro och rädsla. Diskussion: Omvårdnaden är otillräcklig vid diagnostillfället samt postoperativt. Screening har positiv inverkan på patienternas generella hälsa. Konklusion: Studien visade på ökat behov av omvårdnad i samband med att diagnosen ställts samt efter utskrivning postoperativt.

Effects of computer reminders on complications of peripheral venous catheters and nurses' adherence to a guideline in paediatric care : a cluster randomised study

BACKGROUND: Reminder systems in electronic patient records (EPR) have proven to affect both health care professionals' behaviour and patient outcomes. The aim of this cluster randomised trial was to investigate the effects of implementing a clinical practice guideline (CPG) for peripheral venous catheters (PVCs) in paediatric care in the format of reminders integrated in the EPRs, on PVC-related complications, and on registered nurses' (RNs') self-reported adherence to the guideline. An additional aim was to study the relationship between contextual factors and the outcomes of the intervention. METHODS: The study involved 12 inpatient units at a paediatric university hospital. The reminders included choice of PVC, hygiene, maintenance, and daily inspection of PVC site. Primary outcome was documented signs and symptoms of PVC-related complications at removal, retrieved from the EPR. Secondary outcome was RNs' adherence to a PVC guideline, collected through a questionnaire that also included RNs' perceived work context, as measured by the Alberta Context Tool. Units were allocated into two strata, based on occurrence of PVCs. A blinded simple draw of lots from each stratum randomised six units to the control and intervention groups, respectively. Units were not blinded. The intervention group included 626 PVCs at baseline and 618 post-intervention and the control group 724 PVCs at baseline and 674 post-intervention. RNs included at baseline were 212 (65.4 %) and 208 (71.5 %) post-intervention. RESULTS: No significant effect was found for the computer reminders on PVC-related complications nor on RNs' adherence to the guideline recommendations. The complication rate at baseline and post-intervention was 40.6 % (95 % confidence interval (CI) 36.7-44.5) and 41.9 % (95 % CI 38.0-45.8), for the intervention group and 40.3 % (95 % CI 36.8-44.0) and 46.9 % (95 % CI 43.1-50.7) for the control. In general, RNs' self-rated work context varied from moderately low to moderately high, indicating that conditions for a successful implementation to occur were less optimal. CONCLUSIONS: The reminders might have benefitted from being accompanied by a tailored intervention that targeted specific barriers, such as the low frequency of recorded reasons for removal, the low adherence to daily inspection of PVC sites, and the lack of regular feedback to the RNs. TRIAL REGISTRATION: Current Controlled Trials ISRCTN44819426.

Effects of Purified Saccharomyces cerevisiae (1→3)-β-Glucan on Venous Ulcer Healing

Water-insoluble glucan was isolated from the baker’s yeast Saccharomyces cerevisiae. The yeast cells were treated with alkali and the residue then with acid. Chemical and NMR (1D and 2D) analyses showed that a linear (1→3)-β-glucan was purified that was not contaminated with other carbohydrates, proteins or phenolic compounds. The effects of the glucan on wound healing were assessed in human venous ulcers by histopathological analysis after 30 days of topical treatment. (1→3)-β-glucan enhanced ulcer healing and increased epithelial hyperplasia, as well as increased inflammatory cells, angiogenesis and fibroblast proliferation. In one patient who had an ulcer that would not heal for over 15 years, glucan treatment caused a 67.8% decrease in the area of the ulcer. This is the first study to investigate the effects of (1→3)-β-glucan on venous ulcer healing in humans; our findings suggest that this glucan is a potential natural biological response modifier in wound healing

Effects of Purified Saccharomyces cerevisiae (1→3)-β-Glucan on Venous Ulcer Healing

Water-insoluble glucan was isolated from the baker’s yeast Saccharomyces cerevisiae. The yeast cells were treated with alkali and the residue then with acid. Chemical and NMR (1D and 2D) analyses showed that a linear (1→3)-β-glucan was purified that was not contaminated with other carbohydrates, proteins or phenolic compounds. The effects of the glucan on wound healing were assessed in human venous ulcers by histopathological analysis after 30 days of topical treatment. (1→3)-β-glucan enhanced ulcer healing and increased epithelial hyperplasia, as well as increased inflammatory cells, angiogenesis and fibroblast proliferation. In one patient who had an ulcer that would not heal for over 15 years, glucan treatment caused a 67.8% decrease in the area of the ulcer. This is the first study to investigate the effects of (1→3)-β-glucan on venous ulcer healing in humans; our findings suggest that this glucan is a potential natural biological response modifier in wound healing

Cardiovascular changes under normoxic and hypoxic conditions in the air-breathing teleost Synbranchus marmoratus: importance of the venous system

Synbranchus marmoratus is a facultative air-breathing fish, which uses its buccal cavity as well as its gills for air-breathing. S. marmoratus shows a very pronounced tachycardia when it surfaces to air-breathe. An elevation of heart rate decreases cardiac filling time and therefore may cause a decline in stroke volume (VS), but this can be compensated for by an increase in venous tone to maintain stroke volume. Thus, the study on S. marmoratus was undertaken to investigate how stroke volume and venous function are affected during air-breathing. To this end we measured cardiac output (Q), heart rate (fH), central venous blood pressure (PCV), mean circulatory filling pressure (MCFP), and dorsal aortic blood pressures (PDA) in S. marmoratus. Measurements were performed in aerated water (P-O2 > 130 mmHg), when the fish alternated between gill ventilation and prolonged periods of apnoeas, as well as during hypoxia (P-O2 <= 50 mmHg), when the fish changed from gill ventilation to air-breathing. Q increased significantly during gill ventilation compared to apnoea in aerated water through a significant increase in both fH and VS. PCV and MCFP also increased significantly. During hypoxia, when the animals surface to ventilate air, we found a marked rise in fH, PCV, MCFP, Q and VS, whereas PDA decreased significantly. Simultaneous increases in PCV and MCFP in aerated, as well as in hypoxic water, suggests that the venous system plays an important regulatory role for cardiac filling and VS in this species. In addition, we investigated adrenergic regulation of the venous system through bolus infusions of adrenergic agonists (adrenaline, phenylephrine and isoproterenol; 2 mu g kg(-1)). Adrenaline and phenylephrine caused a marked rise in PCV and MCFP, whereas isoproterenol led to a marked decrease in PCV, and tended to decrease MCFP. Thus, it is evident that stimulation of both alpha- and beta-adrenoreceptors affects venous tone in S. marmoratus.