Correlation of Caveolin-1 With Vascular Intimal Thickness for Different Locations of Catheter Tips in a Dog Model

INTRODUCTION

Many studies have reported increased intimal thickness around the catheter tip after catheterization. Caveolin-1 is a protein in the endothelial cell that acts as a shear sensor causing vascular remodeling. This study aimed to elucidate the suitability of different catheter locations and determine the role of caveolin-1 in canine models.

MATERIALS AND METHODS

Tunneled silicone 14.5-F catheters were inserted into the left jugular vein and right femoral vein in 8 dogs. The dogs were separated into 2 groups by catheter location and were followed up for 28 days. All dogs underwent extracorporeal circulation 3 times a week. After animal sacrifice, histological and immunohistochemical assays were performed to measure specific cell populations.

RESULTS

There were higher catheter dysfunction rates and lower blood flow rates in the right femoral vein group compared to the left jugular vein group. There was intimal hyperplasia around the catheter tip in both groups with no significant difference between the two groups. There were caveolin-1 expression in the intimal layer of venous wall around the catheter tip location sites in both groups.

CONCLUSIONS

These findings indicate that different catheter tip locations may influence catheter function and specific targeting of caveonlin-1 could be a strategy of possible future novel therapies for catheter-related vein stenosis.

Distinct Vascular Remodeling Pattern of Adult Rats with Carotid-Jugular Shunt

BACKGROUND

Previous research has revealed that patent vein grafts lose their venous identity Eph-B4 but do not gain arterial identity ephrin-B2 during adaptation to the arterial circulation, and vascular identity marker, for example, the Eph-B4 signaling is a critical determinant of venous wall thickness of vein grafts. But what is the remodeling pattern, especially the remodeling pattern of vascular identity in the venous segment of arteriovenous shunt at a late stage postoperation has not been fully explored. This study was conducted to characterize the remodeling pattern of shear stress, vascular identity, structural composition and morphology, and transcriptional profiles in jugular segment of carotid-jugular (CJ) shunt and/or pulmonary artery (PA), which delivers an increased amount of mixed blood at a late stage postoperation in adult rats.

METHODS

CJ shunt was created in adult Wistar rats via end-to-end anastomosis of carotid artery (CA) and jugular vein (JV). At the time of 15 weeks, after hemodynamics test, remodeled jugular segment of CJ shunt, PA, and sham-operated corresponding vessels were isolated. Reverse transcription polymerase chain reaction, microarray, western blot, immunohistochemistry experiments, and morphology analyses were performed.

RESULTS

CJ shunt shear stresses have been patterned to some sort of balance with no significant difference in shear stress between carotid segment and jugular segment (P > 0.05). Immunohistochemical analysis reveals that venous identity marker Eph-B4 is lost, but arterial identity markers ephrin-B2 and regulator of G-protein signaling 5 are gained in jugular segment of CJ shunt (P < 0.01), and these 2 arterial identity markers further strengthened in PA (P < 0.01) in shunted rats compared with controls. Jugular segment of CJ shunt undergoes significant intimal hyperplasia with strong expression of smooth muscle cell markers (P < 0.05) and demonstrates a distinct transcriptional profiles which reveals that transcripts of 5 arterial markers are significantly upregulated (P < 0.05 or < 0.01) compared with sham-operated JV; among them, G-protein signaling 5 is exactly the gene with the largest fold change (10.14-fold) in all genes tested by microarray experiment.

CONCLUSIONS

Venous identity is lost, but arterial identity is gained in jugular segment of CJ shunt and arterial identity further strengthened in PA in adult shunted rats during late adaptation.

MicroRNA-33 protects against neointimal hyperplasia induced by arterial mechanical stretch in the grafted vein

Aims

Mechanical factors play significant roles in neointimal hyperplasia after vein grafting, but the mechanisms are not fully understood. Here, we investigated the roles of microRNA-33 (miR-33) in neointimal hyperplasia induced by arterial mechanical stretch after vein grafting.

Methods and results

Grafted veins were generated by the 'cuff' technique. Neointimal hyperplasia and cell proliferation was significantly increased, and miR-33 expression was decreased after 1-, 2-, and 4-week grafts. In contrast, the expression of bone morphogenetic protein 3 (BMP3), which is a putative target of miR-33, and the phosphorylation of smad2 and smad5, which are potential downstream targets of BMP3, were increased in the grafted veins. miR-33 mimics/inhibitor and dual luciferase reporter assay confirmed the interaction of miR-33 and BMP3. miR-33 mimics attenuated, while miR-33 inhibitor accelerated, proliferation of venous smooth muscle cells (SMCs). Moreover, recombinant BMP3 increased SMC proliferation and P-smad2 and P-smad5 levels, whereas BMP3-directed siRNAs had the opposite effect. Then, venous SMCs were exposed to a 10%-1.25 Hz cyclic stretch (arterial stretch) by using the FX4000 cyclic stretch loading system in vitro to mimic arterial mechanical conditions. The arterial stretch increased venous SMC proliferation and repressed miR-33 expression, but enhanced BMP3 expression and smad2 and smad5 phosphorylation. Furthermore, perivascular multi-point injection in vivo demonstrated that agomiR-33 not only attenuates BMP3 expression and smad2 and smad5 phosphorylation, but also slows neointimal formation and cell proliferation in grafted veins. These effects of agomiR-33 on grafted veins could be reversed by local injection of BMP3 lentivirus.

Conclusion

The miR-33-BMP3-smad signalling pathway protects against venous SMC proliferation in response to the arterial stretch. miR-33 is a target that attenuates neointimal hyperplasia in grafted vessels and may have potential clinical applications.

Local application of paeonol prevents early restenosis: a study with a rabbit vein graft model

BACKGROUND

Neointimal hyperplasia, which is caused by dysfunction of vascular smooth muscle cells and vascular endothelial cells (VECs), is a foundation for later development of vein grafted occlusion. This study investigates whether neointimal hyperplasia could be prevented by the application of paeonol, a phenolic compound having functions of anti-inflammatory, anti-oxidant, and anti-proliferative.

METHODS

Autologous jugular veins, which engrafted to carotid arteries in rabbits, were enveloped with paeonol or left untreated. After 0, 2, and 3 wk, vein grafts were respectively harvested. Proliferating cell nuclear antigen, vascular cell adhesion molecule l (VCAM-1), and intercellular cell adhesion molecule 1 were assessed with immunohistochemistry and Western blot. VECs apoptosis was also detected with terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling assay.

RESULTS

Paeonol treatment reduced early neointimal hyperplasia by 42%-46% (P < 0.001) and early medial hyperplasia by 18%-22% (P < 0.001) compared with the controls. Immunohistochemical and Western blot results show a significant downregulation of proliferating cell nuclear antigen (P < 0.001) and VCAM-1 (P < 0.001) in paeonol treatment group in the second and third weeks. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling analysis discovered that VECs apoptosis was also reduced by the paeonol treatment in the second and third weeks (P < 0.001).

CONCLUSIONS

Paeonol could prevent vein graft early restenosis by suppressing intimal and medial hyperplasia via inhibition of vascular smooth muscle cells proliferation, VCAM-1 expression, and anti-apoptosis of VECs in grafted veins.

Study on mechanism of c-Myc in restenosis after coronary artery bypass grafting

OBJECTIVE

To study the actions of c-Myc gene fragments in restenosis after coronary artery bypass grafting (CABG).

MATERIALS AND METHODS

A total of 25 healthy pure breeds New Zealand white rabbits were randomly divided into 5 groups according to weight, 5 in each group. The external jugular vein is placed at ipsilateral common carotid artery and sampling at 6h, 2d, 7d, 14d and 28d. The expression of the c-Myc positive cell population was observed in different time using immunohistochemistry and morphological analysis. The thickness and ratio of luminal intima and media were measured by the computer image analytical method.

RESULTS

The luminal intima and media thickness at day 7 is significantly thickening (p <0.01) from 6h while it has not changed (p >0.05) at day 14 and 28 compared to day 7. C-Myc proteins are gradually increased from 6h to day 7, reached a peak (p <0.01) at day 7; started declining from day 14-28. The difference has statistical significance (p <0.01) compared to day 7.

CONCLUSIONS

C-Myc positive cell population has reached a peak after transplantation, which is identical with the peak of fast intimal proliferation. It indicates that c-Myc protein expression is closely associated to intimal proliferation. It can act as an indicator for intimal proliferation after vascular injuries in the early stage of reactions.

Effects of Hypothermic Cardiopulmonary Bypass on Internal Jugular Bulb Venous Oxygen Saturation, Cerebral Oxygen Saturation, and Bispectral Index in Pediatric Patients Undergoing Cardiac Surgery: A Prospective Study

The objective of this study was to evaluate the effect of hypothermic cardiopulmonary bypass (CPB) on cerebral oxygen saturation (rSO2), internal jugular bulb venous oxygen saturation (SjvO2), mixed venous oxygen saturation (SvO2), and bispectral index (BIS) used to monitor cerebral oxygen balance in pediatric patients.Sixty American Society of Anesthesiologists Class II-III patients aged 1 to 4 years old with congenital heart disease scheduled for elective cardiac surgery were included in this study. Temperature, BIS, rSO2, mean arterial pressure, central venous pressure, cerebral perfusion pressure (CPP), and hematocrit were recorded. Internal jugular bulb venous oxygen saturation and SvO2 were obtained from blood gas analysis at the time points: after induction of anesthesia (T0), beginning of CPB (T1), ascending aortic occlusion (T2), 20 minutes after initiating CPB (T3), coronary reperfusion (T4), separation from CPB (T5), and at the end of operation (T6). The effect of hypothermia or changes in CPP on rSO2, SjvO2, SvO2, and BIS were analyzed.Compared with postinduction baseline values, rSO2 significantly decreased at all-time points: onset of extracorporeal circulation, ascending aortic occlusion, 20 minutes after CPB initiation, coronary reperfusion, and separation from CPB (P < 0.05). Compared with measurements made following induction of anesthesia, SjvO2 significantly increased with initiation of CPB, ascending aortic occlusion, 20 minutes after initiating CPB, coronary reperfusion, and separation from CPB (P < 0.05). Compared with induction of anesthesia, BIS significantly decreased with the onset of CPB, aortic cross clamping, 20 minutes after initiating CPB, and coronary reperfusion (P < 0.05). Bispectral index increased following separation from CPB. There was no significant change in SvO2 during cardiopulmonary bypass (P > 0.05). Correlation analysis demonstrated that rSO2 was positively related to CPP (r = 0.687, P = 0.000), with a low linear correlation to temperature (r = 0.453, P = 0.000). Internal jugular bulb venous oxygen saturation was negatively related to temperature (r = -0.689, P = 0.000). Bispectral index was positively related to both temperature (r = 0.824, P = 0.000) and CPP (r = 0.782, P = 0.000). Cerebral oxygen saturation had a positive linear correlation with CPP and a low linear correlation to temperature. Internal jugular bulb venous oxygen saturation had a negative linear correlation to temperature.Pre-and and early postbypass periods are vulnerable times for adequate cerebral oxygenation. Anesthetic management must aim to optimize the supply and demand relationship.

Biochemical neuromonitoring of poor-grade aneurysmal subarachnoid hemorrhage: comparative analysis of metabolic events detected by cerebral microdialysis and by retrograde jugular vein catheterization

OBJECTIVES

In severe aneurysmal subarachnoid hemorrhage (aSAH), pathological changes in cerebral energy metabolism can be detected either by local measurements using cerebral microdialysis (cMD) together with brain tissue oxygen probe or by global measurements of arterio-jugular difference performed with retrograde jugular vein catheter. Our main objective was to compare the two methods of detection and assess whether combining biomarkers from both procedures could improve outcome prediction, which has never been studied before.

METHODS

This study included 400 sets of paired arterial and jugular venous samples and 3138 brain microdialyzates obtained from 18 poor-grade aSAH patients. Using Glasgow outcome scale (GOS), neurochemical data from unfavorable (GOS 1-3) and favorable (GOS 4-5) outcome groups were compared.

RESULTS

The lactate/pyruvate ratio was found as the most sensitive marker for predicting unfavorable outcome (90%), although not specific. In contrast, hypoxic lactate events and those of metabolic ratio (MR) < 3.44, most frequently observed in the unfavorable outcome group than in the favorable one (13.9 vs 0.9% and 33.3 vs 3.75% respectively), were shown to be more specific biomarkers (86%) to predict unfavorable outcome, but less sensitive ( < 70%). The combination of these three biomarkers improved the accuracy of outcome prediction (sensitivity 90% and specificity 71%).

DISCUSSION

Both retrograde jugular venous catheterization (RJVC) and cMD contribute to monitor poor-grade aSAH patients. In this preliminary study, we show that these two techniques are complementary and their combination increases the accuracy of outcome prediction.

The neurological wake-up test does not alter cerebral energy metabolism and oxygenation in patients with severe traumatic brain injury

BACKGROUND

The neurological wake-up test (NWT) is used to monitor the level of consciousness in patients with traumatic brain injury (TBI). However, it requires interruption of sedation and may elicit a stress response. We evaluated the effects of the NWT using cerebral microdialysis (MD), brain tissue oxygenation (PbtiO2), jugular venous oxygen saturation (SjvO2), and/or arterial-venous difference (AVD) for glucose, lactate, and oxygen in patients with severe TBI.

METHODS

Seventeen intubated TBI patients (age 16-74 years) were sedated using continuous propofol infusion. All patients received intracranial pressure (ICP) and cerebral perfusion pressure (CPP) monitoring in addition to MD, PbtiO2 and/or SjvO2. Up to 10 days post-injury, ICP, CPP, PbtiO2 (51 NWTs), MD (49 NWTs), and/or SjvO2 (18 NWTs) levels during propofol sedation (baseline) and NWT were compared. MD was evaluated at a flow rate of 1.0 μL/min (28 NWTs) or the routine 0.3 μL/min rate (21 NWTs).

RESULTS

The NWT increased ICP and CPP levels (p < 0.05). Compared to baseline, interstitial levels of glucose, lactate, pyruvate, glutamate, glycerol, and the lactate/pyruvate ratio were unaltered by the NWT. Pathological SjvO2 (<50 % or >71 %; n = 2 NWTs) and PbtiO2 (<10 mmHg; n = 3 NWTs) values were rare at baseline and did not change following NWT. Finally, the NWT did not alter the AVD of glucose, lactate, or oxygen.

CONCLUSIONS

The NWT-induced stress response resulted in increased ICP and CPP levels although it did not negatively alter focal neurochemistry or cerebral oxygenation in TBI patients.

In vivo nanoparticle assessment of pathological endothelium predicts the development of inflow stenosis in murine arteriovenous fistula

OBJECTIVE

In vivo assessment of pathological endothelium within arteriovenous fistula (AVF) could provide new insights into inflow stenosis, a common cause of AVF primary failure in end-stage renal disease patients. Here we developed nanoparticle-based imaging strategies to assess pathological endothelium in vivo and elucidate its relationship to neointimal hyperplasia formation in AVF.

APPROACH AND RESULTS

Jugular-carotid AVFs were created in C57BL/6 mice (n=38). Pathological endothelium in the AVF was visualized and quantified in vivo using dextranated magnetofluorescent nanoparticles (CLIO-VT680 [cross-linked iron oxide-VivoTag680]). At day 14, CLIO-VT680 was deposited in AVF, but only minimally in sham-operated arteries. Transmission electron microscopy revealed that CLIO-VT680 resided within endothelial cells and in the intimal extracellular space. Endothelial cells of AVF, but not control arteries, expressed vascular cell adhesion molecule-1 and showed augmented endothelial permeability near the anastomosis. Intravital microscopy demonstrated that CLIO-VT680 deposited most intensely near the AVF anastomosis (P<0.0001). The day 14 intravital microscopy CLIO-VT680 signal predicted the subsequent site and magnitude of AVF neointimal hyperplasia at day 42 (r=0.58, P<0.05). CLIO-VT680 deposition in AVF was further visualized by ex vivo MRI.

CONCLUSIONS

AVF develop a pathological endothelial response that can be assessed in vivo via nanoparticle-enhanced imaging. AVF endothelium is activated and exhibits augmented permeability, offering a targeting mechanism for nanoparticle deposition and retention in pathological endothelium. The in vivo AVF nanoparticle signal identified and predicted subsequent inflow neointimal hyperplasia. This approach could be used to test therapeutic interventions aiming to restore endothelial health and to decrease early AVF failure caused by inflow stenosis.

Impact of the blood sampling site on time-concentration drug profiles following intravenous or buccal drug administration

The aim of this study was to examine the effect of the sampling site on the drug concentration-time profile, following intravenous or buccal (often called 'oral transmucosal') drug administration. Buprenorphine (20 μg/kg) was administered IV or buccally to six cats. Blood samples were collected from the carotid artery and the jugular and medial saphenous veins for 24 h following buprenorphine administration. Buprenorphine concentration-time data were examined using noncompartmental analysis. Pharmacokinetic parameters were compared using the Wilcoxon signed rank test, applying the Bonferroni correction. Significance was set at P < 0.05. Following IV administration, no difference among the sampling sites was found. Following buccal administration, maximum concentration [jugular: 6.3 (2.9-9.8), carotid: 3.4 (1.9-4.9), medial saphenous: 2.5 (1.7-4.1) ng/mL], area under the curve [jugular: 395 (335-747), carotid: 278 (214-693), medial saphenous: 255 (188-608) ng·min/mL], and bioavailability [jugular: 47 (34-67), carotid: 32 (20-52), medial saphenous: 23 (16-55)%] were higher in the jugular vein than in the carotid artery and medial saphenous vein. Jugular venous blood sampling is not an acceptable substitute for arterial blood sampling following buccal drug administration.

Central venous-to-arterial CO2-gap may increase in severe isovolemic anemia

Despite blood transfusions are administered to restore adequate tissue oxygenation, transfusion guidelines consider only hemoglobin as trigger value, which gives little information about the balance between oxygen delivery and consumption. Central venous oxygen saturation is an alternative, however its changes reflect systemic metabolism and fail to detect regional hypoxia. A complementary parameter to ScvO₂ may be central venous-to-arterial carbon dioxide difference (CO₂-gap). Our aim was to investigate the change of alternative transfusion trigger values in experimental isovolemic anemia. After splenectomy, anesthetized Vietnamese mini pigs (n = 13, weight range: 18–30 kg) underwent controlled bleeding in five stages (T₁–T₅). During each stage approximately 10% of the estimated starting total blood volume was removed and immediately replaced with an equal volume of colloid. Hemodynamic measurements and blood gas analysis were then performed. Each stage of bleeding resulted in a significant fall in hemoglobin, the O₂-extraction increased significantly from T₃ and ScvO₂ showed a similar pattern and dropped below the physiological threshold of 70% at T₄. By T₄ CO₂-gap increased significantly and well correlated with VO₂/DO₂ and ScvO₂. To our knowledge, this is the first study to show that anemia caused altered oxygen extraction may have an effect on CO₂-gap.

Long-term robust myocardial transduction of the dog heart from a peripheral vein by adeno-associated virus serotype-8

Molecular intervention using noninvasive myocardial gene transfer holds great promise for treating heart diseases. Robust cardiac transduction from peripheral vein injection has been achieved in rodents using adeno-associated virus (AAV) serotype-9 (AAV-9). However, a similar approach has failed to transduce the heart in dogs, a commonly used large animal model for heart diseases. To develop an effective noninvasive method to deliver exogenous genes to the dog heart, we employed an AAV-8 vector that expresses human placental alkaline phosphatase reporter gene under the transcriptional regulation of the Rous sarcoma virus promoter. Vectors were delivered to three neonatal dogs at the doses of 1.35×10(14), 7.14×10(14), and 9.06×10(14) viral genome particles/kg body weight via the jugular vein. Transduction efficiency and overall safety were evaluated at 1.5, 2.5, and 12 months postinjection. AAV delivery was well tolerated and dog growth was normal. Blood chemistry and internal organ histology were unremarkable. Widespread skeletal muscle transduction was observed in all dogs without T-cell infiltration. Encouragingly, whole heart myocardial transduction was achieved in two dogs that received higher doses and cardiac expression lasted for at least 1 year. In summary, peripheral vein AAV-8 injection may represent a simple heart gene transfer method in large mammals. Further optimization of this gene delivery strategy may open the door for a readily applicable gene therapy method to treat many heart diseases.

The acute and chronic effects of monosodium L-glutamate on serum iron and total iron-binding capacity in the jugular artery and vein of pigs

We analyzed the effects of acute and chronic oral administration of monosodium L-glutamate (MSG) on serum iron (Fe) levels and total iron-binding capacity (TIBC) in piglets. In the first experiment, 12 piglets were randomly assigned to two groups: one fed a standard diet (SD) and the other fed an SD containing MSG (10 g/kg). On day 30, serum, liver, kidney, and spleen samples were collected to determine the Fe levels. In the second experiment, six pigs were surgically fitted with a catheter in the jugular artery and vein to investigate the dynamic changes of serum Fe and TIBC. Blood samples were taken from each pig via the catheter every 30 min, for a period of 4 h. The results show that MSG increases Fe levels in the spleen (P < 0.05) and in serum obtained from the jugular artery (P < 0.01). In addition, TIBC in serum obtained from the jugular artery demonstrated an increasing trend in pigs fed the MSG diet; however, this trend was not observed in the jugular vein. In conclusion, MSG increases Fe retention by enhancing TIBC in serum.

Cerebral oxygenation during laparoscopic surgery: jugular bulb versus regional cerebral oxygen saturation

PURPOSE

We hypothesized that regional cerebral oxygen saturation (rSO2) could replace jugular bulb oxygen saturation (SjvO2) in the steep Trendelenburg position under pneumoperitoneum. Therefore, we evaluated the relationship between SjvO2 and rSO2 during laparoscopic surgery.

MATERIALS AND METHODS

After induction of anesthesia, mechanical ventilation was controlled to increase PaCO2 from 35 to 45 mm Hg in the supine position, and the changes in SjvO2 and rSO2 were measured. Then, after establishment of pneumoperitoneum and Trendelenburg position, ventilation was controlled to maintain a PaCO2 at 35 mm Hg and the CO2 step and measurements were repeated. The changes in SjvO2 (rSO2) -CO2 reactivity were compared in the supine position and Trendelenburg-pneumoperitoneum condition, respectively.

RESULTS

There was little correlation between SjvO2 and rSO2 in the supine position (concordance correlation coefficient=0.2819). Bland-Altman plots showed a mean bias of 8.4% with a limit of agreement of 21.6% and -4.7%. SjvO2 and rSO2 were not correlated during Trendelenburg-pneumoperitoneum condition (concordance correlation coefficient=0.3657). Bland-Altman plots showed a mean bias of 10.6% with a limit of agreement of 23.6% and -2.4%. The SjvO2-CO2 reactivity was higher than rSO2-CO2 reactivity in the supine position and Trendelenburg- pneumoperitoneum condition, respectively (0.9 ± 1.1 vs. 0.4 ± 1.2% mm Hg(-1), p=0.04; 1.7 ± 1.3 vs. 0.5 ± 1.1% mm Hg(-1), p<0.001).

CONCLUSION

There is little correlation between SjvO2 and rSO2 in the supine position and Trendelenburg-pneumoperitoneum condition during laparoscopic surgery.

Inhibition of cell surface expression of endothelial adhesion molecules by ursolic acid prevents intimal hyperplasia of venous bypass grafts in rats

OBJECTIVES

Despite rapid progress in surgical techniques, there is still a significant lack of surgery-supportive pharmacological treatments. The aim of this study was to test the hypothesis that ursolic acid (UA) may prevent intimal hyperplasia of venous bypass grafts.

METHODS

The hypothesis was tested by means of primary cell isolation and culture followed by real-time polymerase chain reaction, western blotting, fluorescence microscopy and fluorescence-activated cell sorting analyses, as well as an in vivo rat model for intimal hyperplasia of venous bypass grafts and immunohistochemistry and histochemistry.

RESULTS

The local application of UA significantly inhibited intimal hyperplasia in vivo (intimal thickness control: 25 µm, UA group: 18 µM-8 weeks after surgery). The UA treatment of grafts significantly resulted in reduced endothelial vascular cell adhesion molecule-1 (VCAM-1) expression, reduced infiltration of the grafts vessel wall by CD45-positive cells and increased smooth muscle cell (SMC) death. In in vitro condition, it could be shown that UA inhibits VCAM-1 expression downstream of NFκB and is likely to interfere with VCAM-1 protein synthesis in endothelial cells. Quantification of cell death in vascular smooth muscle cells treated with UA indicated that UA is a potent inducer of SMC apoptosis.

CONCLUSIONS

Our results suggest that UA-mediated inhibition of endothelial VCAM-1 expression reduces the infiltration of venous bypass grafts by CD45-positive cells and inhibits intimal hyperplasia. Apoptosis induction in SMCs may be another method in which UA reduces intimal thickening. UA may constitute a surgery-supportive pharmacon that reduces intimal hyperplasia of vein grafts.

Spontaneous echo contrast in internal jugular veins: a probable indicator for systemic inflammation and a prothrombotic state

The hypothesis that spontaneous echo contrast (SEC) in the internal jugular vein (IJV) is a clinical indicator for systemic inflammation and thrombogenesis is investigated in this study. Fifty-two patients with cardiovascular diseases and 25 nondiseased subjects were evaluated. SEC was observed in 96 of 154 IJVs. The visual grading of SEC showed good interobserver agreement on SEC grades (κ value: 0.846, p < 0.001). Generalized estimating equations analysis was used for univariate and multivariate analysis. Univariate analysis showed that peak flow velocity in corresponding IJV (coefficient -0.001 [95% CI -0.019, -0.001], p = 0.031), jugular venous reflux (JVR, -0.010 [-0.019, -0.001], p = 0.002), plasma levels of fibrinogen (0.464 [0.208, 0.719], p < 0.001) and hs-C-reactive protein (hs-CRP) (0.479 [0.184, 0.774], p = 0.001) and previous history of ischemic stroke (0.779 [0.139, 1.417]; p = 0.017) correlated with the grades of SEC in IJV. Increased plasma levels of fibrinogen and hs-CRP, previous ischemic stroke, lower peak velocity in corresponding IJV and JVR were also independent predictors for the higher grades of SEC in IJV in multivariate regression analysis. SEC in IJV could be evaluated easily and semiquantitatively. SEC in IJVs could be a putative marker of cerebral circulation disturbance and an indicator of systemic inflammatory or prothrombotic state.

[Monitoring of brain function]

Despite being the most important of organs, the brain is disproportionately unmonitored compared to other systems such as cardiorespiratory in anesthesia settings. In order to optimize level of anesthesia, it is important to quantify the brain activity suppressed by anesthetic agents. Adverse cerebral outcomes remain a continued problem in patients undergoing various surgical procedures. By providing information on a range of physiologic parameters, brain monitoring may contribute to improve perioperative outcomes. This article addresses the various brain monitoring equipments including bispectral index (BIS), auditory evoked potentials (AEP), near-infrared spectroscopy (NIRS), transcranial Doppler ultrasonography (TCD) and oxygen saturation of the jugular vein (Sjv(O2)).

Association between cerebrovascular carbon dioxide reactivity and postoperative short-term and long-term cognitive dysfunction in patients with diabetes mellitus

PURPOSE

Our intent was to identify whether cerebrovascular CO(2) reactivity in diabetic patients is a risk factor for postoperative cognitive dysfunction after coronary artery bypass graft (CABG) surgery.

METHODS

One hundred twenty-four diabetic patients undergoing elective CABG were studied and analyzed. Diabetic patients were divided into three groups: normal CO(2) reactivity group (above 5%/mmHg), medium CO(2) reactivity group (between 5 and 3%/mmHg), or impaired CO(2) reactivity group (below 3%/mmHg). After the induction of anesthesia and before the start of surgery, cerebrovascular CO(2) reactivity was measured for all patients. Hemodynamic parameters (arterial and jugular venous blood gas values) were measured during cardiopulmonary bypass. All patients underwent a battery of neurological and neuropsychological tests the day before surgery, 7 days after surgery, and 6 months after surgery.

RESULTS

At 7 days, the rate of cognitive dysfunction in the impaired CO(2) group was higher than in the other three groups (normal, 30%; medium, 25%; impaired, 57%; *P < 0.01 compared with the other groups). In contrast, at 6 months postoperatively, no significant difference in the rate of cognitive dysfunction was found among the three groups. Age, hypertension, CO(2) reactivity, the duration for which jugular venous oxygen saturation (SjvO(2)) was less than 50%, ascending aorta atherosclerosis, diabetic retinopathy, and insulin therapy were independent predictors of short-term cognitive dysfunction in diabetic patients, and HbA1c, diabetic retinopathy, and insulin therapy were independent predictors of long-term cognitive dysfunction in diabetic patients.

CONCLUSIONS

We found that impaired cerebrovascular CO(2) reactivity was associated with postoperative short-term cognitive dysfunction in diabetic patients.

[Pharmacokinetic evaluation of danshensu with in vivo microdialysis in freely moving rat's jugular vein]

OBJECTIVE

To investigate the pharmacokinetics of Danshensu with in vivo microdialysis in freely moving rat's jugular vein.

METHOD

three days after a microdialysis probe introducer was implanted into the jugular vein, a microdialysis probe was introduced to the blood vessel, and began to sample following a single intravenous injection (40 mg x kg(-1)) or a single oral dose (40 mg x kg(-1)) of Danshensu. All the samples were analyzed with HPLC. The concentration of Danshensu in blood were calculated according to the recovery of microdialysis probe and the concentration in dialysates. Pharmacokinetic parameters were than calculated with the concentration-time curve.

RESULT

For intravenous administration, t(1/2 zeta) = (69.62 +/- 33.42) min, AUC(0-infinity) = (3416.24 +/- 779.80) min x mg x L(-1), MRT(0-infinity) = (38.15 +/- 8.61) min, and for oral administration, Cmax = (7.42 +/- 3.08) mg x L(-1), tmax = (31.50 +/- 8.57) min, t(1/2 zeta) = (83.25 +/- 37.35) min, AUC(0-infinity) = (793.19 +/- 101.32) min x mg x L(-1), MRT(0-infinity) = (125.89 +/- 58.27) min. The oral bioavailability of Danshensu F = 22.56%.

CONCLUSION

In vivo microdialysis in freely moving rat's jugular vein is a useful tool to obtain a complete set of free drug concentrations to determine reliable pharmacokinetic parameters.

Cholinergic agonist physostigmine suppresses excessive superoxide anion radical generation in blood, oxidative stress, early inflammation, and endothelial injury in rats with forebrain ischemia/reperfusion

The cholinergic anti-inflammatory pathway is reportedly important in modulating the inflammatory response in local and systemic diseases, including ischemia/reperfusion pathophysiology. In this study, we investigated the effects of the cholinergic agonist, physostigmine, on jugular venous superoxide radical (O(2)(-)) generation, oxidative stress, early inflammation, and endothelial activation during forebrain ischemia/reperfusion (FBI/R) in rats. Fourteen male Wistar rat were allocated to the control group (n=7) or physostigmine group (n=7). The physostigmine group received 80 ng/g physostigmine intraperitoneally 24 h and 1 h before forebrain ischemia was established. The jugular venous O(2)(-) current was measured for 10 min during forebrain ischemia and for 120 min after reperfusion. The O(2)(-) current increased gradually during forebrain ischemia in both groups. The current increased markedly immediately after reperfusion in the control group but was significantly attenuated in the physostigmine group after reperfusion. Brain and plasma malondialdehyde, high-mobility group box 1 (HMGB1) protein, and intercellular adhesion molecule 1 (ICAM1) were significantly attenuated in the physostigmine group compared with the control group, except for brain HMGB1. The amount of O(2)(-) generated during FBI/R correlated with malondialdehyde, HMGB1, and ICAM1 in both the brain and plasma. In conclusion, the cholinergic agonist physostigmine suppressed jugular venous O(2)(-) generation, oxidative stress, early inflammation, and endothelial activation in the brain and plasma in the acute phase of cerebral ischemia/reperfusion. Therefore, the suppression of O(2)(-) is a key mechanism of the cholinergic anti-inflammatory pathway in the pathophysiology of cerebral ischemia/reperfusion.

Evaluation of vascular delivery methodologies to enhance rAAV6-mediated gene transfer to canine striated musculature

A growing body of research supports the development of recombinant adeno-associated viral (rAAV) vectors for delivery of gene expression cassettes to striated musculature as a method of treating severe neuromuscular conditions. However, it is unclear whether delivery protocols that achieve extensive gene transfer in mice can be adapted to produce similarly extensive gene transfer in larger mammals and ultimately patients. Consequently, we sought to investigate methodological modifications that would facilitate rAAV-mediated gene transfer to the striated musculature of canines. A simple procedure incorporating acute (i) occlusion of limb blood flow, (ii) exsanguination via compression bandage, and (iii) vector "dwell" time of <20 minutes, markedly enhanced the transduction of limb muscles, compared with a simple bolus limb infusion of vector. A complementary method whereby vector was infused into the jugular vein led to efficient transduction of cardiomyocytes and to a lesser degree the diaphragm. Together these methods can be used to achieve transgene expression in heart, diaphragm, and limb muscles of juvenile dogs using rAAV6 vectors. These results establish that rAAV-mediated gene delivery is a viable approach to achieving systemic transduction of striated musculature in mammals approaching the dimensions of newborn humans.

[Cerebral uptake and regional cerebral distribution of propofol under concentration equilibrium condition in the internal carotid artery and internal jugular vein in dogs]

OBJECTIVE

To investigate the cerebral uptake and regional distribution of propofol when plasma propofol concentration reaches equilibrium in the internal carotid artery and internal jugular vein in dogs.

METHODS

Eight male hybrid dogs aged 12-18 months weighing 10-12 kg were anesthetized with propofol at a single bolus (7 mg/kg) in 15 s followed by propofol infusion at a constant rate of 70 mg.kg(-1).h(-1) via the great saphenous vein of the right posterior limb. Blood samples were taken from the internal carotid artery and internal jugular vein at 30 min (T30) after propofol infusion for measurement of plasma propofol concentrations by high-pressure liquid chromatography (HPLC). The thalamus, epithalamus, metathalamus, hypothalamus, subthalamus, frontal lobe, parietal lobe, temporal lobe, hippocampus, cingulate gyrus, cerebellum, midbrain, pons, medulla oblongata and cervical cord were then dissected to determine propofol concentrations in these tissues by HPLC.

RESULTS

The propofol concentrations in the internal carotid artery and internal jugular vein blood plasma were comparable at T30 (6.16-/+1.02 vs 6.17-/+1.00 microg/ml, P>0.05). The propofol concentration was 6.11-/+1.07 microg/g in the epithalamus, 6.14-/+0.98 microg/g in the metathalamus, 6.12-/+1.02 microg/g in the hypothalamus, 6.15-/+1.00 microg/g in the subthalamus, 6.20-/+1.03 microg/g in the frontal lobe, 6.18-/+1.02 microg/g in the parietal lobe, 6.13-/+1.00 microg/g in the temporal lobe, 6.07-/+0.99 microg/g in the hippocampus, 6.14-/+1.06 microg/g in the cingulate gyrus, 6.15-/+1.00 microg/g in the cerebellum, 6.13-/+1.05 microg/g in the midbrain, 6.18-/+1.01 microg/g in the pons, 6.15-/+0.93 microg/g in the medulla oblongata, and 6.13-/+1.00 microg/g in the cervical cord, showing no significant differences in the distributions (P>0.05). Propofol concentration in the thalamus (8.68-/+0.88 microg/g) was significantly higher than those in the other brain tissues (P<0.05).

CONCLUSIONS

At the constant intravenous propofol injection rate of 70 mg.kg(-1).h(-1), plasma propofol concentration reaches equilibrium 30 min after the injection in the internal carotid artery and internal jugular vein with even distribution in the cerebral tissues in dogs, but the thalamus contains high propofol concentration.

Gene transfer of COX-1 improves lumen size and blood flow in carotid bypass grafts

BACKGROUND

In autologous saphenous vein grafts, prostacyclin (PGI(1)), a vasoprotective molecule produced by normal endothelial cells, is down-regulated compared with ungrafted saphenous veins and normal carotid arteries. Reduced PGI(2) synthesis may contribute to local platelet deposition, vascular smooth muscle cell (VSMC) accumulation, atherosclerosis, and ultimately failure of venous bypass grafts. We have examined whether gene transfer-mediated overexpression of COX-1 in grafted veins (1) increases PGI(2) and cyclic AMP (cAMP) production, (2) leads to vasodilation and improved local blood flow in the presence of hypercholesterolemia, and (3) reduces neointima formation.

MATERIALS AND METHODS

Jugular veins from New Zealand-White rabbits were incubated for 30 min ex vivo with 1 x 10(10) PFU/mL of an adenoviral vector encoding COX-1 (AdCOX-1; n = 10) or empty control (n = 10) and grafted to the carotid arteries. The rabbits were placed on a high-cholesterol diet for 4 w, and blood flow and histomorphometry of the grafts were assessed.

RESULTS

In the AdCOX-1 group, blood flow was significantly increased (16.0 +/- 3.3 versus 12.5 +/- 3.3 mL/min; P < 0.05) compared with controls, and luminal area (8.9 +/- 1.4 versus 5.3 +/- 1.2 mm(2); P < 0.01) and outer circumference were larger. In six identically treated rabbits, graft PGI(2) and cAMP synthesis was increased at 72 h in AdCOX-1 compared with controls.

CONCLUSION

Our data suggest a 30-min ex vivo exposure of vein grafts to AdCOX-1 increased local synthesis of PGI(2) and cAMP after graft surgery and resulted in better graft lumen and blood flow at 4 w.

[Effect of non-restrictive external stent on the expression of platelet-derived growth factor in vein grafts of rabbits]

OBJECTIVE

To investigate the potential mechanism of non-restrictive external stent in preventing re-stenosis of vein grafts.

METHODS

Thirty-six rabbits underwent reversed bypass grafting of autologous external jugular vein into common carotid artery and then were randomly divided into two equal groups, stenting group (Group S), with an external stent 6 mm in diameter (Dacron vascular prosthesis) surrounding the vein graft, and control group (Group NS) , without stenting. The vein grafts were harvested 7, 14, and 28 days after the operation respectively. Immunocytochemistry was used to detect the platelet-derived growth factor B (PDGF-B) positive cells. The mRNA expression of PDGF-B was detected with RT-PCR.

RESULTS

The PDGF-B positive cell percentages in the intima of Group S 7 and 14 days later were both significantly lower than those of Group NS (15.2% +/- 3.6% vs 21.6% +/- 4.6%, and 6.5% +/- 2.6% vs 12.5% +/- 4.4%, both P < 0.05) . The PDGF-B positive cell percentages in media 7, 14 and 28 days later of Group S were all significantly lower than those of Group NS (13.8% +/- 4.6% vs 25.4% +/- 6.2%, 21.3% +/- 4.4% vs 35.7% +/- 7.3%, and 7.2% +/- 3.2% vs 19.2% +/- 5.4%, all P < 0.01). The PDGF-B positive cell percentage in adventitia peaked 28 days later in Group S and 14 days later in Group NS, and the PDGF-B positive cell percentage in adventitia 28 days later of Group S was significantly higher than that of Group NS (42.5% +/- 8.6% vs 31.9% +/- 4.6%, P < 0.01). RT-PCR analysis revealed that PDGF-B amplification products (457 bp) appeared in both group S and NS from 7 to 28 days, and the PDGF-B mRNA expression levels 7, 14, and 28 days later of Group S were all significantly lower than those of Group NS (31.2% +/- 6.5% vs 45.4% +/- 8.4%, P < 0.05; 42.3% +/- 6.2% vs 65.2% +/- 11.5%, P < 0.01; and 21.3% +/- 5.6% vs 36.2% +/- 9.4%, P < 0.01).

CONCLUSION

Non-restrictive external stenting can inhibit the synthesis of PDGF and change its distribution, which may be one of the mechanisms of external stent in preventing re-stenosis of vein grafts.

Dehydroepiandrosterone and corticosterone are regulated by season and acute stress in a wild songbird: jugular versus brachial plasma

Stress has well-known effects on adrenal glucocorticoid secretion, and chronic elevation of glucocorticoids can have detrimental effects on the brain. Dehydroepiandrosterone (DHEA), an androgen precursor synthesized in the adrenal glands or the brain itself, has anti-glucocorticoid properties, but little is known about the role of DHEA in the stress response, particularly in the brain. Here, we measured the effects of acute restraint on circulating corticosterone (CORT) and DHEA levels in wild song sparrows. Blood was collected from either the brachial or jugular vein. In songbirds, jugular plasma is enriched with neurally synthesized steroids, and therefore, jugular plasma is an indirect index of the neural steroidal milieu. Subjects were sampled during four times of year: breeding, molt, early nonbreeding, and mid-nonbreeding. Baseline CORT and DHEA levels showed similar seasonal changes; both steroids were elevated during the breeding season. Baseline CORT and DHEA levels were similar in jugular and brachial plasma. Acute stress had robust effects on CORT and DHEA that were season specific and vein specific. For CORT, during the molt, stress increased jugular CORT more than brachial CORT. For DHEA, during the breeding season, stress decreased jugular DHEA but not brachial DHEA. During the molt, stress increased jugular DHEA but not brachial DHEA. Acute stress did not affect brachial DHEA. These data suggest that acute stress specifically affects the balance between DHEA synthesis and metabolism in the brain. Furthermore, these results suggest that CORT and DHEA are locally synthesized in the brain during molt, when systemic levels of CORT and DHEA are low.

[Influence of human tissue factor pathway inhibitor gene transfection on neointima formation in vein grafts]

OBJECTIVE

To reduce restenosis in vein grafts after coronary artery bypass grafting, to investigate the effect of human tissue factor pathway inhibitor (TFPI) gene delivery on neointima formation.

METHODS

The eukaryotic expressed plasmid vector pCMV-(Kozak) TFPI was constructed. Forty-eight Japanese white rabbits were randomly divided into 3 groups with 16 rabbits in each group: TFPI group, empty plasmid control group and empty control group. Animal model of common carotid artery bypass grafting was constructed. Before anastomosis, vein endotheliocytes were transfected with cationic liposome containing the plasmid pCMV-(Kozak) TFPI (400 microg) by pressurizing infusion (30 min) in TFPI group. In empty plasmid control group, vector pCMV-(Kozak) TFPI was replaced by empty plasmid pCMV (400 microg). In empty control group, those endotheliocytes were not interfered. After operation, vein grafts were harvested at 3 days for immunohistochemical, RT-PCR and Western-blot analyses of exogenous gene expression and at 30 days for histopathology measurement of intimal areas, media areas and calculation of intimal/media areas ratio. Luminal diameter and vessel wall thickness were also measured by vessel Doppler ultrasonography and cellular category of neointima was analyzed by transmission electron microscope at 30 days after operation.

RESULTS

Human TFPI mRNA and protein were detected in TFPI group. The mean luminal diameter of the TFPI group, empty plasmid control group and empty control group was (2.68 +/- 0.32) mm, (2.41 +/- 0.23) mm and (2.38 +/- 0.21) mm respectively. There were statistically significant differences between TFPI group and control groups (P < 0.05). The vessel wall thickness of the TFPI group, empty plasmid control group and empty control group was (1.09 +/- 0.11) mm, (1.28 +/- 0.16) mm and (1.34 +/- 0.14) mm respectively. There were statistically significant differences between TFPI group and other control groups (P < 0.01). The mean intimal areas, the ratio of the intimal/media areas of the TFPI group were (0.62 +/- 0.05) mm2 and 0.51 +/- 0.08 respectively,whichwere reduced compared withthose of the two control groups (P < 0.05). The mean media areas had no significant differences among three groups (P > 0.05). Through transmission electron microscope analyses,no smooth muscle cells were seen in neointima of TFPI group in many visual fields,but smooth muscle cells were found in neointima of two control groups.

CONCLUSION

Human TFPI gene transfection reduced intimal thickness in vein grafts.

Cerebral metabolism monitoring during hypothermia following resuscitation from cardiopulmonary arrest

BACKGROUND

The aim of the present study was to evaluate cerebral metabolism monitoring during therapeutic hypothermia for global ischemic brain damage after cardiopulmonary resuscitation (CPR).

METHODS

Jugular venous sampling and positron emission tomography (PET) were used. Seven comatose patients with cardiopulmonary arrest underwent hypothermia treatment as soon as possible after CPR. The body temperature of these patients was maintained at 34 degrees C for 72 h. Rewarming was performed at a rate of 1 degrees C/day. To monitor jugular venous saturation (SjO2) and lactate (lac-JV), a fiberoptic catheter was inserted into the jugular bulb. Oxygen extraction fraction (OEF) was calculated using the difference between arterial oxygen saturation (SaO2) and SjO2. 18F-fluorodeoxyglucose (FDG) PET was performed to investigate cerebral glucose metabolism at the end of therapeutic hypothermia.

FINDINGS

The OEF was significantly increased at the end of hypothermia in four patients with favorable outcome on the Glasgow Outcome Scale (hypothermia onset 15.3 +/- 2.0% vs. hypothermia end 30.3 +/- 2.8%, P < 0.05). In three patients with unfavourable outcome (severe or worse on the Glasgow Outcome Scale), end hypothermia OEF tended to be low. There was also a reduction in FDG uptake in these three patients with unfavourable outcome. The lac-JV was significantly decreased at the end ofhypothermia treatment compared with hypothermia onset (27.7 +/- 7.4 vs. 6.0 +/- 3.0 mg/dL, P < 0.05).

CONCLUSIONS

The measurement of cerebral metabolism parameters, especially OEF, might be useful for estimation of hypothermia therapy in patients with unconsciousness after resuscitation after cardiac arrest.

Hyperbaric oxygen therapy for consciousness disturbance following head injury in subacute phase

BACKGROUND

Hyperbaric oxygen (HBO) therapy has been shown to improve outcome after brain injury, however its mechanisms are not understood. The purpose of the present study was to investigate the effect of hyperbaric oxygen (HBO) therapy on the cerebral circulation and metabolism of patients with disturbances in consciousness after head injury in the subacute phase.

METHODS

Seven head injury patients underwent HBO treatment after leaving the intensive care unit. Oxygen (100% O2, 2.7 atm absolute) was delivered to patients in a hyperbaric chamber for 60 min every 24 h (total five treatments/patient). Cerebral circulation monitoring (mean flow velocity: mFV, and pulsatility index: PI at horizontal portion of middle cerebral artery by transcranial Doppler) and cerebral metabolism monitoring (arterio-jugular venous difference of oxygen: AJDO2 and jugular venous lactate: lac-JV) before and after the series of treatments were evaluated.

FINDINGS

Both PI and lac-JV were significantly decreased after HBO theatment, while there were no significant changes in mFV and AJDO2. The decreased PI and lac-JV after HBO therapy might indicate that this treatment couples cerebral circulation and metabolism.

CONCLUSIONS

The measurement of cerebral circulation and metabolism parameters, especially PI and lac-JV, is useful for estimation of effect of HBO therapy in patients with distubances in consciousness after head injury in the subacute phase.

Validation of cerebral venous oxygenation measured using near-infrared spectroscopy and partial jugular venous occlusion in the newborn lamb

Near-infrared spectroscopy combined with partial jugular venous occlusion (JVO) offers promise for determining cerebral venous saturation (CSvO(2)) in sick preterm infants, but has not been validated in the newborn brain or under conditions of hypoxaemia. We assessed the accuracy of the CSvO(2) estimate using cerebral venous oxygen saturation in superior sagittal sinus blood (SSSO(2)) as the 'gold standard'. Comparisons were made in seven newborn lambs over a wide range of arterial oxygen saturations (SaO(2)) of 20% to 100%. Overall, median (range) CSvO(2) was 49.8% (10.6% to 88.5%), whereas SSSO(2) was 45.5% (4.3% to 76.6%); Bland-Altman analysis revealed a mean difference (CSvO(2)-SSSO(2)) of 5.1% and limits of agreement of +/-27.4%. The change in cerebral blood volume (DeltaCBV) induced by JVO increased with SaO(2) (P<0.05). In addition, the strength of the correlation of CSvO(2) with SSSO(2) progressively improved with increasing change in total haemoglobin concentration (DeltaHbT) induced by JVO. With Bland-Altman analysis repeated for data with DeltaHbT >30 micromol cm, the mean difference (CSvO(2)-SSSO(2)) decreased to 2.4% with limits of agreement of +/-18.8%. We conclude that the accuracy of estimating CSvO(2) varies with the DeltaCBV induced by JVO. Potential differences of optical properties between the head of the lamb and the human infant suggest that caution be exercised in directly applying these data to the human newborn. Nevertheless, this critical aspect of the JVO technique needs to be taken into consideration in developing an accurate measurement for sick preterm human infants.

Cerebral arterio-venous pCO2 difference, estimated respiratory quotient, and early posttraumatic outcome: comparison with arterio-venous lactate and oxygen differences

Arterio-venous pCO2 difference (AVDpCO2) and estimated respiratory quotient, the ratio between AVDpCO2 and arterio-venous O2 difference, may be potentially useful estimators of irreversible posttraumatic global cerebral ischemia. Our aim was to evaluate their relevance, along with arterio-venous lactate difference (AVDL) and lactate oxygen index (LOI), in early outcome prediction. The retrospective study involved 55 patients with severe head injury, admitted consecutively in a multidisciplinary intensive care unit of a general hospital. A retrograde jugular catheter was placed as soon as possible, allowing for 324 simultaneous arterio-jugular samples to be taken throughout the first 48-hour postinjury. Early brain death (within 48 h) was assumed to be due to early global ischemia. A multivariate model including clinical and radiologic descriptors and jugular bulb variables showed that a widening of AVDL and LOI was associated with early brain death. Whereas in the patients who died, a progressive worsening of AVDpCO2 and estimated respiratory quotient, associated with corresponding changes in AVDL and LOI were observed, in patients who survived the widening of AVDpCO2 normalized along with that of arterio-venous O2 difference. These findings suggest that the isolated measurement of widening AVDpCO2 is not specific for global cerebral ischemia, but its observation over time could be potentially more useful.

Celiprolol reduces the intimal thickening of autogenous vein grafts via an enhancement of nitric oxide function through an inhibition of superoxide production

BACKGROUND

Beta-adrenoceptor antagonist celiprolol has been widely used as an effective antihypertensive agent. Some studies reported that celiprolol enhances nitric oxide production. The purpose of the present study is to examine the effects of celiprolol on vein graft intimal hyperplasia and endothelium-dependent nitric oxide (NO)-mediated relaxation.

METHODS

Japanese white rabbits were randomized to a control group that was fed regular rabbit chow or to a celiprolol group that was fed regular rabbit chow supplemented with 100 mg/body celiprolol sodium. The reversed jugular vein was implanted into the carotid artery. At 2 and 4 weeks after the operation, vein grafts in both groups were harvested, and intimal hyperplasia of the vein grafts was assessed. At 4 weeks after the operation, harvested vein grafts from both the groups were examined on the endothelium-dependent relaxation by application of Ach and were examined to detect for endothelial NO synthase (eNOS) expression and superoxide anion production.

RESULTS

Celiprolol inhibited intimal hyperplasia of carotid interposition-reversed jugular vein grafts 4 weeks after implantation (Intima/media index of celiprolol group, 0.48 +/- 0.01 vs control group, 1.07 +/- 0.08, P < .05) and suppressed cell proliferation in the neointima 2 weeks after implantation. In addition, celiprolol significantly enhanced endothelium-dependent NO-mediated relaxation in the vein graft with no change in eNOS expression and a reduction in superoxide production.

CONCLUSIONS

These novel findings clearly demonstrate that beta-adrenoceptor antagonist celiprolol can suppress intimal hyperplasia of the vein graft, which may be due to the enhancement of nitric oxide function through an inhibition of superoxide production. These results strongly support the clinical usefulness of celiprolol administration for preventing intimal hyperplasia of the vein graft after bypass grafting.

Blockade of monocyte chemoattractant protein-1 by adenoviral gene transfer inhibits experimental vein graft neointimal formation

BACKGROUND

Clinical outcome of vascular bypass surgery using autologous vein graft is limited by neointimal formation associated with vein graft failure. Because inflammatory changes are one of the main pathologic features of vein graft failure, monocyte chemoattractant protein-1 (MCP-1) might therefore underlie in the mechanism of vein graft failure. There is no direct evidence, however, that shows the benefits of local anti-MCP-1 therapy as a novel molecular approach for prevention of vein graft failure.

METHODS

To block MCP-1, we used an N-terminal deletion mutant of the MCP-1 gene (7ND), which lacks the N-terminal amino acids 2 to 8, binds to its receptor CCR2, and blocks MCP-1-mediated monocyte chemotaxis. 7ND works as dominant-negative inhibitor of MCP-1. Autologous canine jugular vein grafts were transfected by incubating them ex vivo in a solution with or without adenovirus vectors containing 7ND gene or LacZ gene, and interposed into the carotid arteries.

RESULTS

Adenovirus-mediated gene transfer of 7ND, but not LacZ gene transfer, significantly attenuated inflammation (monocyte infiltration per mm2 on day 7: 328+/-59, 220+/-11, 26+/-4 in control, LacZ, and 7ND groups, respectively, P<.05, n=4 each) and proliferation (appearance of proliferating cells per mm2 on day 7: 1005+/-186, 756+/-106, 252+/-27 in control, LacZ, and 7ND groups, P<.05, n=4 each) at 7 days after the operation and thus suppressed neointimal formation (neointimal area in mm2 on day 28: 1.63+/-0.51, 1.96+/-0.48, 0.68+/-0.10 in control, LacZ, and 7ND groups, P<.05, n=4 each). This strategy also attenuated upregulation of MCP-1 activities but did not affect endothelial regeneration process.

CONCLUSIONS

Blockade of MCP-1 by adenoviral gene transfer of 7ND limits neointimal formation associated with vein graft failure in dogs. This study highlights the potential therapeutic benefit of local anti-MCP-1 therapy for prevention of neointimal formation associated with vein graft failure.

[Cerebral distribution of propofol at cerebral propofol uptake equilibrium in dogs]

OBJECTIVE

To investigate the cerebral distribution of propofol during continued infusion at a constant rate when the cerebral propofol uptake reaches equilibrium in dogs.

METHODS

Six healthy 1-year-old male dogs were used in this study. The venous channel was established in the great saphenous vein of the right posterior limb. Anesthesia was induced with a single bolus injection of propofol (7 mg/kg), followed by propofol infusion at a constant rate of 70 mg/(kg.h) using a microinfusion pump. The blood samples were taken from the right internal carotid and internal jugular vein at 30 min (T30) and 50 min (T50) during propofol infusion for measurement of plasma propofol concentrations with high performance liquid chromatography (HPLC). At T50, the frontal lobe, parietal lobe, temporal lobe, hippocampus, cingulate gyrus, thalamus, midbrain, pons, and cerebellum were dissected respectively for determination of propofol concentrations.

RESULTS

Propofol concentrations in the internal carotid artery and internal jugular vein blood plasma were 3.107-/+1.067, 3.095-/+1.085 microg/ml at T30 and 3.091-/+1.101, 3.117-/+1.091 microg/ml at T50, respectively, showing no significant differences (P>0.05). Propofol concentrations in the frontal lobe, parietal lobe, temporal lobe, hippocampus, cingulate gyrus, thalamus, midbrain, pons, cerebellum at T50 were 3.085-/+1.123, 3.116-/+1.125, 3.073-/+1.159, 3.117-/+1.090, 3.075-/+1.178, 3.073-/+1.146, 3.075-/+1.151, 3.102-/+1.174, and 3.072-/+1.192 microg/g respectively, suggesting homogeneous propofol distribution in these cerebral tissues (P>0.05).

CONCLUSION

At T50, the cerebral uptake of propofol reached equilibrium when propofol is distributed homogeneously in the cerebral tissues in dogs.

Percutaneous heart valve replacement: histology and calcification characteristics of biological valved stents in juvenile sheep

INTRODUCTION

Percutaneous techniques to replace the pulmonary valve are emerging as an alternative to congenital cardiac surgical procedures. Promising experimental and early clinical results have been reported so far, focusing on technical feasibility and valved stent function. The present study aimed to describe the micropathology after experimental percutaneous valve replacement.

METHODS

Self-expanding nitinol stents carrying a valved bovine jugular vein were transfemorally implanted into the pulmonary position of nine sheep. After 3 months of survival, macro- and micropathological examinations were carried out using standard staining techniques and immunohistochemistry. Additionally, calcification characteristics were determined by X-ray examinations and von Kossa stainings.

RESULTS

Six of nine animals survived the 3-month study time with good angiographic and echocardiographic function. All valves were grossly functional at the time of explantation. Slight fibrous overgrowth was seen at the inflow portions of two valved stents. No cuspal perforations or intracuspal hematomas were observed. Light microscopy proved the absence of cellular inflammatory infiltrates in any tissue samples. The myocardium directly proximal to the stent appeared structurally normal without calcification. The overall structure of the native pulmonary artery was well preserved with few mineral deposits spread diffusely throughout the wall distal to the stent. Massive calcification appeared in the bovine jugular-vein wall together with increased numbers of T lymphocytes. Neither calcific deposits in the cusps nor extrinsic mineralization was noted.

CONCLUSION

For the first time, micropathologic evaluation of percutaneously implanted heart valves is described. The results demonstrate that calcification of valved stents occurs in the wall portions without affecting the cusps. The cardiac structures in the vicinity had normal histology without inflammation.

TGF-beta- and CTGF-mediated fibroblast recruitment influences early outward vein graft remodeling

Luminal shearing forces have been shown to impact both geometric remodeling and the development of intimal hyperplasia. Less well studied is the influence of intramural wall stresses on vessel growth and adaptation. Using a vein graft-fistula configuration to isolate the impact of circumferential wall stress, we identify the reorganization of adventitial myofibroblasts as the dominant histological event that limits early outward remodeling of vein grafts in response to elevated wall stress. We hypothesize that increased production of transforming growth factor-beta (TGF-beta) and connective tissue growth factor (CTGF) induces recruitment of myofibroblasts, promotes adventitial reorganization, and limits early outward remodeling in response to increased intramural wall stress. Vein grafts with a distal arteriovenous fistula in the neck of rabbits were constructed, resulting in a fourfold differential in circumferential wall stress. Using this model, we demonstrate 1) elevated wall stress augments the production of TGF-beta and CTGF, 2) increased TGF-beta expression and CTGF expression are correlated with the enhanced differentiation from fibroblasts to myofibroblasts, as evidenced by the significant increase in the alpha-actin-positive cells in adventitia, and 3) the levels of TGF-beta, CTGF, and alpha-actin are inversely correlated with the magnitude of outward remodeling of the graft wall. Increased wall stress after vein graft implantation appears to induce a TGF-beta- and CTGF-mediated recruitment of adventitial fibroblasts and a conversion to a myofibroblast phenotype. Although important in the maintenance of wall stability in the face of an increased mechanical load, this adventitial adaptation limits early outward remodeling of the vein conduit and may prove deleterious in maintaining long-term vein graft patency.

Tumor necrosis factor-alpha and the early vein graft

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) has been implicated in the blood vessel wall response to hemodynamic forces. We hypothesized that TNF-alpha activity drives neointimal hyperplasia (NIH) during vein graft arterialization and that anti-TNF-alpha therapy would inhibit NIH.

METHODS

Rabbits underwent bilateral vein grafting using jugular vein. All distal branches except the occipital artery were unilaterally ligated to create distinct flow environments between the bilateral grafts. Vein grafts were harvested sequentially up to 28 days for TNF-alpha messenger RNA (mRNA) quantitation. In separate experiments, animals received short-term or long-term dosing with pegylated soluble TNF-alpha type I receptor (PEG sTNF-RI) or vehicle. After 14 to 28 days, grafts were analyzed for morphometry, proliferation, apoptosis, and PEG sTNF-RI distribution.

RESULTS

Quantitative mRNA assay (TaqMan) revealed shear-dependent (P < .001) and time-dependent (P < .001) TNF-alpha expression. TNF-alpha induction was maximal at day 1 and gradually decreased over time, but was persistently elevated even 4 weeks later (P < .001). Low shear (associated with increased NIH) resulted in significantly higher TNF-alpha mRNA expression (P = .03). PEG sTNF-RI was found in high concentrations in the serum and localized to NIH. The high-flow and low-flow vein grafts from treated animals demonstrated similar volumes of NIH compared with controls. PEG-sTNF-RI had only modest impact on vascular wall cell turnover, as reflected by terminal deoxynucleotide transferase-mediated deoxy uridine triphosphate nick-end labeling (P = .064) and anti-Ki-67 (P = .12) assays.

CONCLUSIONS

Placement of a vein into the arterial circulation acutely upregulates TNF-alpha; this expression level correlates with the degree of subsequent NIH. Pharmacologic interruption of this signaling pathway has no significant impact on NIH or wall cellular proliferation/apoptosis, suggesting that early vein graft adaptations can proceed via TNF-alpha-independent mechanisms.

NF-kappaB activity and iNOS expression in monocytes from internal jugular blood of migraine without aura patients during attacks

This study investigated nuclear factor-kappa B (NF-kappaB) activity by electrophoresis mobility gel shift assay and IkappaBalpha expression by Western blot analysis in monocytes obtained from serial samples of internal jugular venous blood taken from seven migraine patients without aura during attacks. Inducible nitric oxide synthase (iNOS) expression was also assessed by reverse transcription-polymerase chain reaction. An increase in NF-kappaB activity peaked 2 h after attack onset. This was accompanied by a transient reduction in IkappaBalpha expression. Up-regulation of iNOS was evident at 4 h, maintained at 6 h and reduced at the end of the attack. These findings substantiate the hypothesis of transitory delayed inflammation, as suggested by the animal model, and suggest the possibility of using therapeutic approaches to target NF-kappaB transcription in the treatment of migraine.

Angiotensin II and tumor necrosis factor-alpha upregulate survivin and Kruppel-like factor 5 in smooth muscle cells: Potential relevance to vein graft hyperplasia

BACKGROUND

Survivin (SVV) is a unique inhibitor of apoptosis protein (IAP) that regulates both apoptosis and mitosis. Recent work suggests that SVV plays a critical role in the vascular injury response, but the molecular pathways remain unclear.

METHODS

We examined the expression of SVV and the transcription factor, KLF5, in human venous smooth muscle cells (VSMC) by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot analysis after treatment with angiotensin II (Ang II) or tumor necrosis factor-alpha (TNF-alpha). An adenoviral construct expressing SVV or GFP was also employed to assess effects on KLF5 expression. A rabbit carotid interposition vein graft model was used to assess the relevance of KLF5 to bypass graft healing.

RESULTS

Stimulation of VSMC with Ang II and TNF-alpha led to a rapid upregulation of KLF5 expression, and a later increase in SVV, which was cell-cycle independent. Overexpression of SVV in VSMC led to an early and persistent induction of KLF5. KLF5 was upregulated in rabbit vein grafts early (1 day) after grafting.

CONCLUSIONS

We speculate that SVV is a central point of convergence of multiple signaling pathways in vascular injury, and that it regulates the local amplification of these pathways in the vessel wall.

Gene expression changes evoked in a venous segment exposed to arterial flow

OBJECTIVE

This study was conducted to characterize the coordinated molecular changes evoked in the structure and composition of the wall of a venous segment when exposed to fistula flow.

METHODS

An arteriovenous shunt was created in adult C57BL/6J mice. Remodeled veins and contralateral control jugular veins were isolated 7 days after surgery. Total RNA was isolated, linearly amplified, and the transcriptional profiles of this early adaptive response were obtained by microarray analysis. Histologic and immunohistochemical analyses were performed on remodeled veins and control veins isolated on days 1, 3, 5, and 7 after surgery to further examine distinct spatial and temporal aspects of this early process.

RESULTS

There were 131 significantly upregulated and 165 downregulated genes in the remodeled vein compared with the control jugular vein. Genes involved in extracellular matrix reorganization were highly upregulated. Movat's pentachrome staining revealed ground substance on day 3 that was not observed on day 5. The appearance of elastin fibers was first observed on day 7. Morphometric analysis demonstrated maximum wall thickness on day 3. Immunohistochemical analysis revealed the presence of tenascin-C, thrombospondin, lysyl oxidase, and osteopontin in different cell types at different time points throughout the first week after surgery.

CONCLUSION

Major changes in the organization of the extracellular matrix occur during the early response of venous remodeling. Elastin, tenascin-C, thrombospondin, lysyl oxidase, and osteopontin are expressed within the wall of the remodeling vein resulting in the de novo formation of an extracellular matrix scaffold that may be part of a critical adaptation program being evoked to allow the vessel to cope with its new biomechanical environment.

CLINICAL RELEVANCE

The Kidney Dialysis Outcomes Quality Initiative has proposed the construction of arteriovenous fistulas as the primary vascular access for hemodialysis. As the vein is exposed to arterial flow, the vein wall dilates and a vascular remodeling process is triggered. With continued exposure, intimal hyperplasia occurs at the anastomosis that in many cases leads to failure. However, the molecular mechanisms by which the outflow vein remodels into a mature fistula remain incompletely understood. By investigating venous remodeling in a fistula model, candidate genes important for the remodeling process are discovered and their functional significance examined. Thus, the identification of relevant genes involved in this process should provide insight into arteriovenous fistula maturation and may suggest novel approaches for achieving higher patency rates.

MR susceptometry for measuring global brain oxygen extraction

Monitoring of oxygen saturation in jugular venous blood gives an estimate of the balance of global oxygen delivery and cerebral oxygen consumption. We present a noninvasive approach to measure oxygen saturation in vivo in the internal jugular vein using MR susceptometry by exploiting the characteristic susceptibility of deoxyhemoglobin, and demonstrate the feasibility of performing such measurements in a group of subjects. We assessed the sensitivity of the method for detecting small changes in oxygen saturation by monitoring the variations observed during breath-holding and hypoventilation experiments. Unlike alternative methods, the susceptometric technique does not require calibration.

Expression of hypoxia-inducible factor-1 and vascular endothelial growth factor in response to venous hypertension

OBJECTIVE

Experimentally, a fistula created surgically between the carotid artery and jugular vein, together with occlusion of venous sinuses, generate venous hypertension, which can induce dural arteriovenous fistula formation intracranially in rats. Our aim was to study the effect of nonischemic venous hypertension on the elaboration of the angiogenic signal, hypoxia-inducible factor-1 (HIF-1), and its downstream signal, vascular endothelial growth factor (VEGF).

METHODS

Sixty rats were exposed to venous hypertension for periods ranging from 4 hours to 3 weeks. Western blot analysis, transbinding assays, enzyme-linked immunosorbent assays, and immunohistochemistry quantified HIF-1 and VEGF expression in brain. Forty-eight control rats underwent similar surgical procedures without creating venous hypertension. Cerebral blood flow was measured at baseline, after surgery, and before sacrifice.

RESULTS

Venous hypertension did not impair cerebral blood flow. Relative to controls, HIF-1 expression increased fivefold in response to venous hypertension (P < 0.005), with peak expression 1 day later localized to endothelial cells in venules next to the sagittal sinus. VEGF expression also increased threefold in response to venous hypertension (P < 0.05), with peak expression 7 days later localized to parasagittal astrocytes. HIF-1 and VEGF were minimally expressed in rat normal venous pressures.

CONCLUSION

In this model, venous hypertension stimulates angiogenesis by a mechanism other than ischemia. HIF-1 expression may result from dilation of parasagittal veins and endothelial deformation. HIF-1 and VEGF seem to be molecular agents that convert venous hypertension into intracellular signals and angiogenesis activity.

Multiwavelength optoacoustic system for noninvasive monitoring of cerebral venous oxygenation: a pilot clinical test in the internal jugular vein

A noninvasive, high-resolution optoacoustic technique is a promising alternative to currently used invasive methods of brain oxygenation monitoring. We present the results of our pilot clinical test of this technique in healthy volunteers. Multiwavelength optoacoustic measurements (with nanosecond optical parametric oscillator as a source of radiation) were performed on the area of the neck overlying the internal jugular vein, a deeply located large vein that drains blood from the brain and from extracranial tissues. Optoacoustic signals induced in venous blood were measured with high resolution and signal-to-noise ratio despite the presence of a thick layer of overlying tissue (up to 10 mm). The characteristic parameters of the signal at different wavelengths correlated well with the spectrum of the effective attenuation coefficient of blood.

Decreased hepatic insulin extraction precedes overt noninsulin dependent (Type II) diabetes in obese monkeys

Many obese middle-aged rhesus monkeys (Macaca mulatta) spontaneously develop noninsulin dependent diabetes mellitus (NIDDM). Basal hyperinsulinemia and increased stimulated plasma insulin levels are associated with this obesity and precede the onset of overt diabetes. The present studies sought to determine the relative contributions of enhanced insulin secretion and of reduced insulin clearance to this early obesity-associated hyperinsulinemia. Direct simultaneous measurement of portal and jugular vein insulin levels in two normal monkeys showed a constant rate of hepatic insulin extraction of 56+/-3% over the range of peripheral insulin levels from 351+/-113 to 625+/-118 pmol/L. In 33 additional monkeys ranging from normal to diabetic, basal C-peptide levels were examined as an indicator of beta-cell secretion and the molar ratio of plasma C-peptide to insulin (C/I ratio) under basal steady state conditions calculated as an index of hepatic insulin extraction. Well in advance of overt diabetes, there was a progressive decline of 67% in the apparent hepatic insulin extraction rate in association with increased obesity and plasma insulin levels. Basal insulin levels and hepatic insulin extraction returned toward normal in monkeys with impaired glucose tolerance and in those with overt diabetes. We conclude that reduced insulin disposal, probably due to reduced hepatic extraction of insulin, in addition to increased beta-cell activity, contributes to the development of basal hyperinsulinemia in obese rhesus monkeys progressing toward NIDDM. In addition, in overt diabetes, normal hepatic insulin extraction in the presence of limited beta-cell secretion may exacerbate the hypoinsulinemic state.

Effects of Increasing Concentrations of Propofol on Jugular Venous Bulb Oxygen Saturation in Neurosurgical Patients under Normothermic and Mildly Hypothermic Conditions

Background

Recent evidence suggested that propofol can deteriorate the cerebral oxygen balance compared with inhalational anesthetics. However, dose-related influences of propofol on cerebral oxygen balances were not clearly investigated. In the current study, the authors investigated the effects of increasing concentrations of propofol on jugular venous bulb oxygen saturation (Sj(O2)) in neurosurgical patients under normothermic and mildly hypothermic conditions.

Methods

After institutional approval and informed consent were obtained, 30 adult patients undergoing elective craniotomy were studied. Patients were randomly allocated to either normothermic or hypothermic group (n = 15 in each group). In the normothermic and hypothermic groups, tympanic membrane temperature was maintained at 36.5 degrees and 34.5 degrees C, respectively. Sj(O2) was measured at predicted propofol concentrations of 3, 5, and 7 microg/ml using a target-controlled infusion system in both groups.

Results

At a predicted propofol concentration of 3 microg/ml, there were no significant differences in Sj(O2) values between the normothermic and hypothermic groups, although the incidence of desaturation (Sj(O2) &lt; 50%) was significantly higher in the normothermic group than in the hypothermic group (30% vs. 13%; P &lt; 0.05). Sj(O2) values and the incidence of desaturation remained unchanged during the changes in predicted propofol concentration from 3 to 7 microg/ml both in the normothermic and hypothermic groups.

Conclusion

The results indicated that the increasing concentrations of propofol did not affect Sj(O2) values in neurosurgical patients under normothermic and mildly hypothermic conditions.

No increase of calcitonin gene-related peptide in jugular blood during migraine

Increased calcitonin gene-related peptide (CGRP) in external jugular venous blood during migraine attack is one of the most cited findings in the headache literature. The finding has not been convincingly reproduced and is based on comparison with historic control subjects. The validity of this finding is important for the understanding of migraine. We therefore investigated the issue using an intrapatient comparison design and two different CGRP assays. We sampled blood from the external jugular and cubital vein during, as well as outside of, an attack of migraine without aura. We succeeded in 17 patients, whereas only cubital fossa blood could be sampled in an additional 4 patients. CGRP was measured with the same assay as most previous studies (assay I) and furthermore with a more sensitive and validated assay (assay II). For assay I, mean CGRP concentration in external jugular venous blood during attack was 17.18 pmol/L compared with 15.88 pmol/L outside of attack. Mean difference was 1.81 pmol/L (95% confidence interval [CI]: -2.88, 6.41; p = 0.44). In peripheral blood during attack, CGRP was 16.86 pmol/L compared with 17.57 pmol/L outside of attack. Mean difference was -0.79 pmol/L (95% CI: -4.64, 3.06; p = 0.69). For assay II, external jugular venous blood concentration of CGRP during attack was 32.59 pmol/L compared with 30.59 pmol/L outside of attack; mean difference was 2.00 pmol/L (standard error, 2.39; 95% CI: -3.07, 7.07; p = 0.416). In peripheral blood during attack, CGRP was 33.37 pmol/L compared with 31.84 pmol/L outside of attack; mean difference was 1.53 pmol/L (standard error, 1.90; 95% CI: -2.46, 5.51; p = 0.431). Thus, no difference between CGRP level in external jugular or cubital fossa blood during and outside of attack was found. No difference was found between external jugular and peripheral venous blood. Thus, previous findings of increased CGRP level in external jugular or cubital fossa venous blood could not be confirmed. Our finding strongly suggests that CGRP is not increased in jugular venous blood during migraine without aura. CGRP cannot be used as a biomarker to validate human or animal models of migraine.

Liposomalization of lactoferrin enhanced it's anti-inflammatory effects via oral administration

It is known that lactoferrin is one of the functional proteins contained in mammalian milk and that it plays an important role in the immune system. In this study, we prepared multi-lamellar liposomal bovine lactoferrin composed of egg yolk phosphatidylcholine and phytosterol for oral delivery, and examined any resulting anti-inflammatory effects. Oral pretreatment of liposomal lactoferrin exhibited more suppressive effects than did non-liposomal lactoferrin on CCl4-induced hepatic injury in rats as well as on lipopolysaccharide-induced TNF-alpha production from mouse peripheral blood mononuclear leukocytes. Further investigation revealed that the liposomalization did not exert influence on the absorbability of lactoferrin to the venous blood or lymph following an intraduodenal administration in rats. Furthermore, there was no significant difference exhibited between the antigenicity of liposomal and non-liposomal lactoferrin, which was measured using the passive cutaneous anaphylaxis reaction following oral sensitization to them in guinea pigs. These results suggest that liposomal lactoferrin might act more effectively than conventional lactoferrin in the intestinal site, which is regarded as an active site of orally administered lactoferrin, although the biological mechanism is not fully understood yet. Consequently we propose that liposomal lactoferrin could be a novel active constituent useful for preventive and therapeutic treatment of inflammatory diseases.

Changes in jugular bulb oxygen saturation during off-pump coronary artery bypass graft surgery

BACKGROUND

The effect of haemodynamic derangement during coronary artery anastomosis in off-pump coronary artery bypass surgery on cerebral blood flow has not been elucidated. Jugular bulb oxygen saturation is a useful indicator of cerebral blood flow provided that the cerebral metabolic rate is constant. This study was designed to evaluate the changes in jugular bulb oxygen saturation during off-pump coronary artery bypass surgery.

METHODS

With IRB approval, 48 patients were included. After anaesthesia, an 18-G catheter was introduced into the jugular bulb. Haemodynamic variables and oxygen profiles from gas analysis of jugular bulb blood and arterial blood were obtained: after sternotomy (baseline); at 5 min after the beginning of the anastomosis of the left anterior descending artery, obtuse marginal artery, and right coronary artery; and after sternal closure.

RESULTS

Cardiac index and mixed venous oxygen saturation decreased significantly during anastomosis of all three arteries compared to the baseline value. Although the changes in jugular bulb oxygen saturation during anastomosis were statistically significant compared to its baseline value, jugular bulb oxygen saturation remained within normal limit throughout the study.

CONCLUSIONS

Jugular bulb oxygen saturation, which represents the global cerebral oxygenation, was well maintained during the anastomosis of all coronary arteries despite significant haemodynamic changes during off-pump coronary artery bypass (OPCAB).

Donitriptan decreases jugular venous oxygen saturation in rats in the absence of cranial vasoconstriction: an overlooked mechanism of antimigraine action?

The aim of the present study was to determine whether donitriptan and sumatriptan decreased jugular venous oxygen saturation and increased carbon dioxide partial pressure in venous blood. However, previous studies conducted with these compounds cannot discriminate whether the decrease of venous oxygen saturation is dependent of cranial vasoconstrictor. In the present study, vehicle (n = 10), donitriptan (2.5, 10, and 40 microg/kg; n = 8) or sumatriptan (630 microg/kg; n = 8) were infused into the carotid artery in the anesthetized rat. Regional blood flows were evaluated in the presence of donitriptan (10 microg/kg; n = 6) or vehicle (n = 6). Jugular venous oxygen saturation was significantly decreased by donitriptan (from 10 microg/kg) with maximal changes of -32.9 +/- 8.0%. Jugular carbon dioxide partial pressure was increased by donitriptan, reaching maximal changes of 17.7 +/- 4.6% (P < 0.05 versus vehicle). Similarly, sumatriptan significantly decreased venous oxygen saturation and increased jugular carbon dioxide partial pressure. These changes induced by donitriptan are abolished by the 5-hydroxytryptamine (5-HT)(1B/1D) receptor antagonist GR 127935 (N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]-2-[-methyl-4(5-methyl-1,2,4)-oxadiazol-3-yl]-(1,1 biphenyl)-4-carboxamide dihydrochloride). In addition, donitriptan was devoid of significant effects on systemic arterial pressure, heart rate, or regional blood flows, including systemic arterial-jugular venous anastomotic, systemic, or cranial. The results demonstrate that donitriptan increases cerebral oxygen consumption by 5-HT(1B/1D) receptor activation in the absence of cranial vasoconstriction.

Jugular bulb desaturation during coronary artery surgery: a comparison of off-pump and on-pump procedures † †Presented in part at the annual Outcomes Meeting at Key West, FL, USA, 2001. ‡ ‡This article is accompanied by the Editorial

BACKGROUND

Conventional coronary artery bypass surgery has been associated with cerebral injury attributed to cardiopulmonary bypass (CPB) and surgical manipulation of the ascending aorta. Off-pump coronary artery surgery avoids these factors and could prevent cerebral injury. However, moving the heart from its natural position affects the circulation and could compromise cerebral oxygenation and perfusion. We set out to compare episodes of poor global cerebral oxygenation, defined as a jugular bulb saturation less than 50%, between patients randomized to off-pump or (conventional) on-pump coronary artery surgery.

METHODS

One hundred and eighty-seven patients were assigned randomly to off-pump or on-pump coronary artery surgery. Oxygen saturation in the jugular bulb (SjO2) was measured during revascularization of the three main coronary vessels in the off-pump group, and at the start of CPB, before rewarming, and after rewarming in the on-pump group. We compared samples with jugular bulb with desaturation (SjO2) < or = 50%) between treatment groups.

RESULTS

One hundred and seventy-five patients (81 in the off-pump group [93%] and 94 in the on-pump group [94%]) had complete jugular oxygen saturation data. Thirty-nine patients in the off-pump group (48%) and 25 patients in the on-pump group (27%) had one or more samples with desaturation during revascularization or CPB (odds ratio after adjustment for other factors, 0.39; 95% confidence interval, 0.21-0.73, P<0.01).

CONCLUSION

Jugular bulb desaturation occurs more frequently during off-pump coronary artery surgery than during conventional coronary artery surgery.