Structural determination of N-2''-hydroxyoctadecenoyl-1-O-beta-D-glucopyranosyl-9-methyl-4, 8-sphingadienine from species of Aspergillus

The barrier function, surface biochemistry, and morphology of confluent monolayers of endothelial cells isolated from different segments of the bovine lung vasculature [microvessels (BLMVEC), vein (BPVEC) and artery (BPAEC)] were grown in culture and compared. A number of common cell surface proteins were identified along with two proteins of 46 and 48 kDa found exclusively on BPVEC. Lectin affinity chromatography revealed multiple glycosylation differences. The lectins, Arachis hypogaea (AHA) and Lycopersicum esculentum (LEA) agglutinins, interacted with several glycoproteins of BLMVEC but not of BPAEC. Bandeiraea simplicifolia (BS-1) and Caragana arborescens (CAA) agglutinins recognized several glycoproteins of BPVEC and BPAEC but not BLMVEC. Permeabilities were much lower for BLMVEC than BPAEC or BPVEC monolayers, with a range of about 16-fold less for sucrose to 2-fold less for albumin. Electron microscopy revealed that BLMVEC have a greater surface density of plasmalemmal vesicles (approximately 4-fold) and more extensively developed intercellular junctions with more focal membrane adhesion sites per junction (approximately 9-fold) than the other cells. We conclude that: i) BLMVEC monolayers form a much more restrictive barrier to molecular transport as a result of the tighter junctional formation; and ii) endothelial surface glycoproteins may be differentially glycosylated depending on their segmental location within the vasculature.     

Atypical beta-adrenoceptors in the rat isolated common carotid artery

1. The possible existence of atypical beta-adrenoceptors in vascular smooth muscle of the rat common carotid artery was examined in this study. 2. Isoprenaline produced concentration-dependent relaxation of noradrenaline (10(-7) M) precontracted ring segments of the carotid artery. The relaxation was not affected by endothelial denudation. 3. Propranolol (10(-8) M-3 x 10(-7) M) shifted the isoprenaline curve to the right without suppressing the maximum response. However, the slope (0.74) of the Schild plot was significantly (P < 0.05) less than 1. 4. Salbutamol (beta 2), CGP 12177 and BRL 37344 (beta 3) also concentration-dependently relaxed noradrenaline precontracted artery segments. These relaxations were not affected by propranolol (10(-7) M). Pretreatment of the artery segments with BRL 37344 did not desensitize the tissue to the relaxant effect of isoprenaline, CGP 12177 and salbutamol. 5. It is concluded that atypical beta-adrenoceptors exist in vascular smooth muscle of the common carotid artery.     

Do parental convict cichlids of different sizes value the same brood number equally?

OBJECTIVES: We sought to determine endothelium-dependent vasodilator function in the brachial artery of patients with microvascular angina pectoris. BACKGROUND: Previous studies suggest the presence of endothelial dysfunction of the coronary microcirculation in patients with microvascular angina pectoris. It is not known whether endothelial dysfunction in these patients is a generalized process or whether it is confined to the coronary microcirculation only. METHODS: In 11 women (mean [+/-SD] age 60.1 +/- 7.8 years) with microvascular angina (anginal pain, normal epicardial coronary arteries, positive exercise stress test), endothelium-dependent vasodilation was assessed in the brachial artery by measuring the change in brachial artery diameter in response to hyperemic flow. Results were compared with 11 age- and gender-matched patients with known three-vessel coronary artery disease and 11 age- and gender-matched healthy control subjects. In all subjects, the intima-media thickness (IMT) of the common carotid artery was also measured. RESULTS: Flow-mediated dilation (FMD) was comparable in patients with microvascular angina and coronary artery disease (1.9 +/- 2.5% vs. 3.3 +/- 3.3%, p = NS) but was significantly lower in patients with microvascular angina than in healthy control subjects (1.9 +/- 2.5% vs. 7.9 +/- 3%, p < 0.05). IMT was significantly lower in patients with microvascular angina than in those with coronary artery disease (0.64 +/- 0.08 vs. 1.0 +/- 0.28 mm, p < 0.05) and was comparable between patients with microvascular angina pectoris and healthy control subjects (0.64 +/- 0.08 vs. 0.56 +/- 0.14 mm, p = NS). IMT > or = 0.8 mm was observed in 1 of 11 patients with microvascular angina, 1 of 11 control subjects and 10 of 11 patients with coronary artery disease. CONCLUSIONS: These findings suggest that endothelial dysfunction in microvascular angina is a generalized process that also involves the peripheral conduit arteries and is similar to that observed in atherosclerotic disease. IMT could be helpful in discriminating patients with microvascular angina and atherosclerotic coronary artery disease.     

Surgical treatment of common carotid artery occlusion

Eight patients with common carotid artery (CCA) occlusion underwent bypass with saphenous vein to either the carotid bifurcation (five), the internal carotid artery (two), or the external carotid artery (one). Indications included ipsilateral transient ischemic attack (two), recent nondisabling hemispheric stroke (two), and transient nonhemispheric cerebral symptoms (two). Two asymptomatic patients with CCA occlusion and contralateral internal carotid stenosis underwent prophylactic revascularization prior to planned aortic surgery. There were no perioperative strokes, occlusions, or deaths. Late ipsilateral stroke occurred in two patients, and one patient had a single transient ischemic attack after 2 years. The four patients with preoperative transient cerebral ischemia experienced relief of their symptoms. Duplex ultrasound is an accurate screening modality for distal patency. Collateral filling of the internal or external carotid artery can usually be demonstrated after aortic arch or retrograde brachial contrast injection. End-to-end distal anastomosis after endarterectomy eliminates the original occlusive plaque as a potential source of emboli. The subclavian artery is preferred for inflow on the left. The CCA origin is easily accessible for inflow on the right. Bypass of the occluded CCA is safe and may be effective in relieving transient cerebral ischemic symptoms, although long-term ipsilateral neurologic sequelae may still occur.     

Observations of Surface Relief of Proeutectoid Widmanstätten Cementite Plates in a Hypereutectoid Carbon Steel

Proeutectoid Widmanstätten cementite in a hypereutectoid carbon steel was found to be associated with a surface relief effect. A hot-stage microscope was used for heat treatment and in situ observation. Widmanstätten cementite plates were obtained near the surface of the specimen. The surface relief effect of Widmanstätten cementite plates was quantitatively characterized by atomic force microscopy. It was found that the relief had either a typical tent shape or apex-lost tent shape. The relief tilt angles were of considerable dispersion, ranging from 20 deg to 50 deg.     

Estimation of the pulmonary capillary wedge pressure from transesophageal pulsed Doppler echocardiography of pulmonary venous flow: influence of the respiratory cycle during mechanical ventilation

AIM: Endothelial Dysfunction (ED) is an early functional marker and Intima-Media-Thickness (IMT) an early morphological parameter of atherogenesis. Is there a simple, non-invasive routine method for the identification of atherosclerosis including the detection of the early functional endothelial impairment seen for example in Type 2 diabetic patients? METHODS: Using high resolution ultrasound we studied peripheral endothelial function expressed as flow-associated dilation (FAD %) and endothelial independent vasodilation after administration of 400 micrograms glycerol trinitrate (postnitro %) of the brachial artery as well as IMT of the common carotid artery in 25 Type 2 diabetic patients and their matched controls. RESULTS: (mean +/- SD): The diabetic patients showed a remarkable ED (FAD%: 3.8 +/- 3.3 vs. 6.9 +/- 4.4%, p = 0.01) and an already increased IMT (0.72 +/- 0.14 vs. 0.62 +/- 0.10 mm, p < 0.01). The similar postnitro % in diabetic patients and controls suggests normal dilating capacity of the studied vessels in the diabetic patients (postnitro %: 14.3 +/- 9.4 vs. 14.9 +/- 8.5%, p = ns). CONCLUSION: With a combination of these three sonomorphological parameters it is possible to document the stage of atherosclerosis including endothelial dysfunction in Type 2 diabetic patients.     

Endothelial activation and development of coronary artery disease in transplanted human hearts

CONTEXT: The development of coronary artery disease in heart transplants is often associated with graft failure. Early detection of allografts prone to develop this disease is essential to institute new therapeutic approaches that could prolong allograft function. OBJECTIVE: To determine if early activation of arterial/arteriolar endothelium predicts the development of coronary artery disease, graft failure, or both in transplanted human hearts. DESIGN: Prospective cohort study. SETTING: Heart Transplant Center. PARTICIPANTS: A total of 121 consecutive adult cardiac allograft recipients who received transplants between 1988 and 1995 and were followed up through 1996. MAIN OUTCOME MEASURES: Development of coronary artery disease and graft failure. METHODS: Immunocytochemistry was performed on serial endomyocardial biopsy specimens to evaluate endothelial activation markers (intercellular adhesion molecule-1 and histocompatibility antigen HLA-DR) in arteries and arterioles. The presence and progression of coronary artery disease was evaluated by annual coronary angiograms with side-by-side comparisons. RESULTS: None of the 121 donor hearts showed arterial/arteriolar endothelial activation before transplantation. Arterial/arteriolar endothelial activation was present in 78 and absent in 43 of 121 allografts during the first 3 months after transplantation. The time of appearance and the proportion of biopsy specimens showing endothelial activation during these first 3 months were significantly associated with the risk of developing coronary artery disease, the progression of the disease, and the time required to develop the disease (P<.001). Significantly more patients with arterial/arteriolar endothelial activation died or received a second transplant (P<.001). CONCLUSIONS: Activation of arterial/arteriolar endothelium in transplanted human hearts predicts development of coronary artery disease and increased risk of graft failure.     

Internal mammary vein to coronary artery anastomotic fistula

Two patients are presented where internal mammary artery grafting was performed for the relief of symptomatic coronary artery disease. At follow-up the internal mammary artery was occluded and a communication between the internal mammary vein and the native coronary artery was demonstrated. These patients were characterised by the early recurrence of angina or the appearance of a continuous murmur. Both patients were treated by re-operation with ligation of the arterio-venous fistula and saphenous vein grafting.     

Hepatic amebiasis among patients in a public teaching hospital

A peptide fraction of low molecular weight (Vueffe) prepared from bovine Factor VIII by enzymatic hydrolysis with trypsin, reduces significantly (p<0.05) membrane bound protein kinase C (PKC) activity in cultured bovine pulmonary artery endothelial cells grown with enhanced glucose levels (22.2 mM) or stimulated by phorbol 12-myristate 13-acetate (PMA). The activation of PKC is a common pathway by which mediators increase transendothelial permeability during tissue inflammation and in the development of diabetic vascular complications. Our results suggest that the antihaemorrhagic properties of Vueffe could be related to a decrease in endothelial permeability mediated by PKC.     

Expression of inducible nitric oxide synthase after endothelial denudation of the rat carotid artery: role of platelets

There is functional evidence suggesting that endothelial denudation stimulates inducible nitric oxide synthase (iNOS) activity in the vascular wall. In vitro studies have shown that iNOS expression in smooth muscle cells is reduced by endothelial cells. In the present study we have analyzed the time course of iNOS protein expression in the arterial wall after in vivo deendothelialization. Endothelial denudation was performed in the left carotid artery of Wistar rats, and the right carotid artery was used as control. Whereas iNOS protein was weakly expressed 6, 24, and 48 hours after endothelial denudation, a marked iNOS expression was found 7, 14, and 30 days after vascular damage. Because platelet adhesion and aggregation occur early after endothelial damage, we studied the role of activated platelets in the negative modulation of iNOS protein expression during the first 2 days after endothelial denudation. Early after in vivo endothelial injury, platelet-depleted rats showed a marked iNOS protein expression in the vascular wall. Similar results were obtained by blocking the platelet glycoprotein (GP) IIb/IIIa. Although iNOS protein is present in the arterial wall several days after endothelial denudation, early after arterial wall injury iNOS protein is weakly expressed. Platelets play a crucial role in preventing iNOS protein expression early after endothelial damage, an effect that can be avoided with GP IIb/IIIa blockers. Although iNOS protein was weakly expressed in vivo in the rat carotid artery wall 6, 24, and 48 hours after balloon endothelial denudation, a marked iNOS expression was found 7, 14, and 30 days after arterial damage. iNOS expression could be increased early after endothelial injury by removing circulating platelets and by an antibody against the GP IIb/IIIa. In conclusion, platelets prevent iNOS protein expression early after endothelial balloon damage, an effect that can be avoided with GP IIb/IIIa blocking agents.     

Presence of an expressed beta-tubulin gene (TUBB) in the HLA class I region may provide the genetic basis for HLA-linked microtubule dysfunction

Cyclophosphamide (CP) is associated with significant pulmonary toxicity; however, the mechanism of toxicity is unknown. An in vitro endothelial model of injury was developed to assess the direct toxic effects of CP, CP derivatives and CP metabolites on cultured endothelial cells. Injury to 51Cr-labeled bovine artery pulmonary endothelial (BPAE) cells was quantified by the release of 51Cr from BPAE cells incubated for 18 h with injury expressed as a cytotoxic index. Because CP activation and metabolism occurs primarily in liver, assays assessing CP effects were conducted in the presence of an hepatic microsomal enzyme system. Upon activation, CP produces 4-hydroxycyclophosphamide, acrolein (ACR) and the alkylating metabolite, phosphoramide mustard. Nonactivated CP demonstrated no toxicity to BPAE cells within 18 h; whereas, activated CP induced significant BPAE cell injury in a concentration-dependent manner. Specific metabolites of CP 4-hydroxycyclophosphamide and ACR were markedly more toxic to BPAE cells than phosphoramide mustard. Sulfhydryl-rich compounds, S-2-(3-aminopropylamino)ethylphosphoric acid (WR-2721) and N-acetylcysteine, significantly reduced 4-hydroxycyclophosphamide- and ACR-induced injury but had no significant protective effect against phosphoramide mustard-induced toxicity. These studies suggest 1) CP is not metabolized within pulmonary artery endothelial cells, 2) ACR may be the principal CP metabolite involved in mediating direct injury to pulmonary artery endothelial cells and 3) sulfhydryl-rich agents may be effective in reducing CP-induced damage to critical endothelial cell barriers.     

Anomalous thymic branch of the right common carotid artery

A previously unreported anomalous thymic artery that branched from the anterior aspect of right common carotid artery approximately 1 cm above bifurcation of the brachiocephalic artery was found during routine dissection. It traveled inferiorly through a plexus of inferior thyroid veins for 6 cm in front of the brachiocephalic artery and crossed the anterior surface of the trachea where it divided into two branches that supplied the right and left lobes of the thymus. The development and blood supply of the thymus and their clinical anatomy are reviewed.     

Cell adhesion and short-term patency in human endothelium preseeded 1.5-mm polytetrafluoroethylene vascular grafts: an experimental study

It has been shown that endothelialization improves short-term patency of 1.5-mm expanded polytetrafluoroethylene vascular grafts. A model for endothelialization of 1.5-mm expanded polytetrafluoroethylene vascular grafts with human endothelial cells is described. In this model, the adherence of endothelial cells was increased significantly in grafts coated with serum proteins and collagen. By means of this protocol, graft patency was tested after implantation in two animal models: the rat aorta and the rabbit common carotid artery. Anastomosis was performed with a 3M Precise Microvascular Anastomotic System. In both animal models, no significant loss of endothelial cells in the precoated grafts (rat, n = 8) were noted 1 hour after blood flow restoration. All uncoated grafts showed significant endothelial cell loss. In the rabbit model, all nonendothelialized grafts (n = 8) clotted 5 to 25 minutes after flow restoration. Seven (n = 8) endothelialized grafts showed no clotting during 1 hour's observation: one clotted immediately for a patency rate of 87.5 percent. These results indicate that endothelialization of 1.5-mm grafts is practical. Furthermore, adhesion of endothelial cells to the graft walls is not affected by short-term, pulsatile, high-pressure blood flow.     

Immunoaffinity localization of the enzyme xanthine oxidase on the outside surface of the endothelial cell plasma membrane

BACKGROUND: Reactive oxygen metabolites generated from endothelial xanthine oxidase (XO) trigger reperfusion injury in many organs. We evaluated the possibility that endothelial XO was localized on the endothelial cell surface, as well as within the cytoplasm. METHODS: Primary cultures of bovine (BAECs) and porcine (PAECs) aortic endothelial cells were grown in media documented to be free of XO. Polyclonal and monoclonal antibodies were developed against XO. These antibodies were used to evaluate BAEC and PAEC for cell surface XO through immunofluorescence staining, hybridoma cell surface labeling, and endothelial cell surface binding. RESULTS: These antibodies bound specifically to the surface of these cells when the membrane was shown to be intact and impermeable (and the cytoplasm inaccessible) to immunoglobulins Moreover, hybridoma cells expressing monoclonal antibody to XO bound specifically to the endothelial cell surface. Finally, intact endothelial cells bound specifically to the anti-XO polyclonal antibodies immobilized to the surface of a Petri dish. The integrity of these endothelial cell plasma membranes was demonstrated by the subsequent growth and replication of these cells in culture. CONCLUSIONS: These findings indicate that XO is present on the outside surface of the endothelial cell plasma membrane. This would not only explain the known in vivo efficacy of intravascularly administered large molecular weight antioxidants (such as superoxide dismutase) but could have important implications for inflammatory signaling.     

Protection of the renal artery in nephron-sparing surgery. I. Pathomorphological study

It is necessary to clamp the renal artery for some time in renal surgery to preserve the organ. Not only the renal parenchyma but also the wall of the clamped renal artery may be damaged due to known ischaemic-reperfusion causes. Regional venous renal hypothermia induced by intracellular solutions (Sacks II, Euro-Collins) could provide protection against damage of the vessel wall caused by reperfusion or clamping in our experiments, in cases of clamping for 30 minutes, probably because it also ensured the cooling of the surface of the vessel wall. Similar vasoprotective effect could be achieved by systematic antioxidant treatment (MTDQ-DS) and regional renal hypothermia given in combination. Harmful effects of 45-minute clamping could be best avoided by applying antioxidant treatment alone. While there were no significant morphological changes in the renal arteries the persistent endothelial damage may trigger further complications like renal ischaemic condition.     

Distribution of endogenous albumin in the rat glomerulus: role of hemodynamic factors in glomerular barrier function

Using an ultrastructural immunoperoxidase technique, the distribution of endogenous albumin in the rat glomerulus was delineated under normal and abnormal hemodynamic conditions. Superficial glomeruli in anesthetized Munich-Wistar rats were rapidly fixed in situ by applying glutaraldehyde to the renal surface. Fixed tissue slices were treated with anti-rat albumin Fab fragments conjugated to horseradish peroxidase (HRP), and were then subjected to the Graham-Karnovsky ultrastructural peroxidase localization procedure. During normal blood flow, dense reaction product specific for albumin was largely confined to the glomerular capillary lumen and endothelial fenestrae, with only small amounts detectable in the lamina rara interna, and none deeper in the basement membrane (GBM) or in the urinary space. If cortical tissue was subjected to routine immersion fixation, or if fixation was performed in situ after ligation of the renal artery, reaction product was detected throughout the GBM and in the urinary space. If fixation was performed in situ after ligation of the renal artery and vein (or artery, vein and ureter), reaction product was found in the GBM and, in very large amounts, in the urinary space. If blood flow was restored for ten minutes after five minutes of renal pedicle (artery and vein) occlusion, the distribution of albumin returned to normal. Thus, glomerular barrier function depends upon the maintenance of normal blood flow conditions.     

The surge in Medicare managed care: an update

Purines of ATP, ADP, AMP and adenosine released from rat caudal artery with and without endothelium and the isolated smooth muscle and endothelial cells were examined, in order to determine the source. Treatment of intact segments of caudal arteries with noradrenaline (10 microM) for 3 min induced a large release of ATP, ADP, AMP and adenosine. However, if the artery segments had been denuded of their endothelial lining, noradrenraline induced only a slight release of purines. Endothelial cells in primary culture prepared from caudal arteries, when exposed to noradrenaline for 3 min released large amounts of purines, whereas vascular smooth muscle cells prepared similarly and passaged endothelial cells did not release purines upon exposure to noradrenaline. These results indicate that, of smooth muscle and endothelial cells of the vascular wall, only intact endothelial cells react to alpha-adrenoceptor stimulation by releasing adenine nucleotides and adenosine.     

Ischemic preconditioning attenuates postischemic coronary artery endothelial dysfunction in a model of minimally invasive direct coronary artery bypass grafting

OBJECTIVE: Unmodified reperfusion without cardioplegia in minimally invasive direct coronary artery bypass grafting procedures causes endothelial dysfunction that may predispose to polymorphonuclear neutrophil-mediated myocardial injury. This study tested the hypothesis that ischemic preconditioning in a minimally invasive direct coronary artery bypass grafting model attenuates postischemic endothelial dysfunction in coronary vessels. METHODS: In anesthetized dogs, the left anterior descending coronary artery was occluded for 30 minutes and reperfused for 3 hours without ischemic preconditioning (no-ischemic preconditioning; n = 7); in 7 dogs, the left anterior descending occlusion was preceded by 5 minutes occlusion followed by 5 minutes of reperfusion. Relaxation responses to stimulators of nitric oxide synthase were used to evaluate endothelial function in arteries from the ischemic-reperfused (left anterior descending) and nonischemic (left circumflex coronary artery) zones. RESULTS: Stimulated endothelial-dependent relaxation of epicardial left anterior descending artery to incremental concentrations of acetylcholine in the no-ischemic preconditioning animals was shifted to the right, and maximal relaxation was attenuated compared with the nonischemic left circumflex coronary artery (117% +/- 4% vs 138% +/- 5%). In contrast, acetylcholine-induced maximal relaxation was comparable in the left anterior descending artery versus left circumflex coronary artery in the ischemic preconditioning group (130% +/- 6% vs 135% +/- 5%). In 150- to 200- microm left anterior descending microvessels, 50% relaxation occurred with a lower concentration (log[M]) of acetylcholine in ischemic preconditioning versus no-ischemic preconditioning (-8.0 +/- 0.4 vs -7.0 +/- 0.1) with no group differences in smooth muscle relaxation to sodium nitroprusside, suggesting endothelial-specific damage. Adherence of fluorescent labeled polymorphonuclear neutrophils to epicardial coronary artery endothelium, used as an index of basal (unstimulated) anti-polymorphonuclear neutrophil function, was significantly attenuated by ischemic preconditioning versus no-ischemic preconditioning (293 +/- 25 polymorphonuclear neutrophils/mm2 vs 528 +/- 29 polymorphonuclear neutrophils/mm2). CONCLUSION: In this minimally invasive direct coronary artery bypass grafting model, both agonist-stimulated and basal postischemic endothelial dysfunction were attenuated by ischemic preconditioning.     

Successful balloon dilation of an abdominal coarctation of the aorta in patient with presumed Takayasu's aortitis

An 11-year-old male with a severe abdominal aortic coarctation, presumably secondary to aortitis, underwent successful percutaneous balloon dilation that resulted in near-complete relief of the obstruction. Intravascular ultrasound imaging showed a major endovascular tear immediately following dilation and satisfactorily excluded significant branch (superior mesenteric) artery compromise. Arterial remodeling was demonstrated with persistence of the gradient relief over a 12-month follow-up period.     

Changes in the heparin affinity of extracellular-superoxide dismutase in patients with coronary artery atherosclerosis

Extracellular-superoxide dismutase [EC 1.15.1.1] (EC-SOD) is a secretory glycoprotein with high affinity for heparin. This enzyme locates in blood vessel walls at a high enough level to suppress oxidative stress under normal conditions. EC-SOD is the major SOD isozyme in plasma, anchored to heparan sulfate proteoglycans in the glycocalyx of endothelial cell surfaces. Plasma EC-SOD is heterogeneous in heparin affinity and can be divided into five fractions, I to V, by heparin-HPLC. It has been suggested that EC-SOD form V is the primary form synthesized in the body and that EC-SOD forms with reduced heparin affinity are the result of proteolytic truncation of the C-terminal end of EC-SOD form V which is responsible for the binding with heparin. Recently, we reported that only plasma EC-SOD form V, with the highest heparin affinity, was increased by intravenous injection of heparin. The heparin affinity of plasma EC-SOD in patients with coronary atherosclerosis (CA+ patients) was compared in this study. The increase of plasma EC-SOD form V after heparin injection in CA+ patients was significantly less than that in subjects without evidence of stenosis in their major coronary arteries (CA- subjects). On the other hand, in CA+ patients, EC-SOD forms I to III, with low heparin affinity, were significantly increased compared to those in CA- subjects. EC-SOD in plasma apparently forms an equilibrium between the plasma phase and endothelial cell surface, and EC-SOD on the endothelial cell surface contributes to protecting the vessel wall against oxidative stress. These findings suggest that the quantitative and qualitative changes of EC-SOD, i.e., the decrease of bound EC-SOD on the endothelial cell surface, might suppress the defense systems against oxidative stress, which causes in part the development of coronary artery atherosclerosis.