Coagulation factor Xa induces endothelium-dependent relaxations in rat aorta

The relaxing effect of coagulation factor Xa on phenylephrine-contracted rat aortic rings was compared with the effect of thrombin and trypsin. All three proteases induced a dose-dependent relaxation in the presence of an intact endothelium. EC50 values were 3 +/- 1, 24 +/- 9, and 16 +/- 1 nmol/L for thrombin, trypsin, and factor Xa, respectively. Whereas thrombin induced rapid relaxations followed by partial recontraction, trypsin and factor Xa induced slower sustained effects. Factor Xa-induced relaxations were not affected by hirudin at high concentrations (1 mumol/L) but were abolished by DX9065A, a specific inhibitor of the catalytic activity of factor Xa. Furthermore, no relaxations to factor Xa could be elicited in the presence of the NO synthase inhibitor N omega-nitro-L-arginine methyl ester (100 mumol/L), whereas relaxations were not altered in the presence of the inactive enantiomer N omega-nitro-D-arginine methyl ester (100 mumol/L). Addition of factor Xa together with thrombin induced relaxations that were larger than those induced by thrombin alone, whereas factor Xa had no additional effects on trypsin-induced relaxations. Further-more, factor Xa relaxed thrombin-desensitized aortic rings but was ineffective in trypsin-desensitized tissues. These data suggest that factor Xa acts on a cleavable endothelial receptor that induces NO release, resulting in the relaxation of precontracted rat aortic rings. Factor Xa does not act through endothelial thrombin receptors but may activate another cleavable trypsin-sensitive receptor.     

Natural dietary polyphenolic compounds cause endothelium-dependent vasorelaxation in rat thoracic aorta

This study investigated the possible active principles which support the endothelial nitric oxide-dependent relaxation produced by red wine and other plant polyphenolic compounds in thoracic aorta from male Wistar rats (12-14 wk old). Relaxation experiments were recorded isometrically on vessels precontracted with norepinephrine. Ten different chromatographic fractions (3-18 mg) isolated from red wine polyphenolic compounds (RWPC) and some available defined polyphenols (10-15 mg) were tested. Fractions enriched into either anthocyanins or oligomeric condensed tannins exhibited endothelium-dependent vasorelaxant activity (maximal relaxation in the range of 59-77%) comparable to the original RWPC. However, polymeric condensed tannins elicited a weaker vasorelaxant activity than the original RWPC (maximal relaxation ranged between 20-47%, P < 0.01). Moreover, the representative of either phenolic acid derivatives (benzoic acid, vanillic acid, gallic acid), hydroxycinnamic acid (p-coumaric acid, caffeic acid) or the flavanol [(+)-epicatechin] classes failed to induce this type of response. Among the anthocyanins, delphinidin (maximal relaxation being 89%), but not malvidin or cyanidin, showed endothelium-dependent vasorelaxation. These results show that anthocyanins and oligomeric-condensed tannins exhibited a pharmacological profile comparable to the original RWPC. These compounds may be involved in the reduction of cardiovascular mortality related to the presence of wine, fruits and vegetables in the diet.     

Effects of chylomicrons and chylomicron remnants on endothelium-dependent relaxation of rat aorta

The effects of chylomicrons and chylomicron remnants on endothelium-dependent relaxation of rat aorta were studied in vitro. Chylomicrons and chylomicron remnants were prepared in vivo. Aortic rings were incubated with the lipoproteins for 45 min before the vessels were constricted with phenylephrine and concentration relaxation response curves constructed to carbachol, ATP, A23187 and S-nitroso-N-acetylpenicillamine. Maximum % relaxations to carbachol were significantly reduced by both chylomicrons and chylomicron remnants but responses to ATP and S-nitroso-N-acetylpenicillamine were unaffected. In addition, chylomicrons significantly inhibited A23187-induced relaxation, causing an increase in the EC50 value. Chylomicron remnants cause selective inhibition of carbachol-induced relaxation suggesting an action at the receptor or G protein-coupled component of the receptor-mediated activation of the L-arginine-nitric oxide pathway. Chylomicrons appear to be less selective in their inhibition of the endothelium-dependent relaxation. This study demonstrates that lipoprotein particles of dietary origin may cause endothelial cell dysfunction.     

Effects of preanesthetic and anesthetic drugs on endothelium-dependent responses in the rat aorta

1. Acetylcholine often fails to induce endothelium-dependent relaxation in human vessels in vitro. Due to the fact that most of these vessels come from surgery, we examined the influence of drugs used in anesthesia on endothelium-dependent responses in rat aorta. 2. Groups of male Wistar rats of the following treatments were utilized: P group, diazepam+promethazine+atropine; I group, pentothal+succinylcholine; IG group, halothane+nitrous oxide; M group, morphine+pancuronium; C group, untreated rats. Dose-response curves to noradrenaline and acetylcholine were determined in rat aorta in vitro, in the presence and absence of endothelium. 3. Acetylcholine induced more relaxation (P < 0.05) in the rat aorta of IG group compared with that of the C group. 4. In the rat aorta from P and IG groups, the contractions produced by several concentrations of noradrenaline were significantly smaller (P < 0.05) when the endothelium was removed. Similar effects occurred in aorta strips of animals previously treated with either atropine, promethazine, cimetidine or halothane. 5. Our results suggest that drugs currently used in anesthesia interfere with some endothelium-dependent effects on isolated rat aorta but according to these results they do not seem to be responsible for the lack of acetylcholine relaxation sometimes described in human vessels in vitro.     

Acute or chronic exercise alters angiotensin II-induced contraction of rat aorta

Chronic exercise substantially shifted the dose-response curve for angiotensin II (ANG II)-induced contractions to the right with increases in the EC50 value in both endothelium-intact and endothelium-denuded aortae. An acute endurance exercise also caused a 3-fold increase in the EC50 value in both endothelium-intact and endothelium-denuded aortae from sedentary control rats. Whereas, no substantial increase in the EC50 value was observed in trained rats after an acute endurance exercise. Thus, chronic exercise attenuates ANG II receptor-mediated contraction of rat aortae. An acute exercise also caused the reduced responses to ANG II in sedentary control rats but not in chronically exercise-trained rats.     

Exercise training alters the Ca2+ and contractile responses of coronary arteries to endothelin

We tested the hypothesis that alterations in myoplasmic free Ca2+ (Ca(m)) regulation in coronary smooth muscle after exercise training (Ex) underlie changes in vasomotor function. Yucatan miniature pigs were endurance trained by treadmill running for 16-20 wk. Simultaneous determination of Ca(m) (fura-2 microfluorometry) and contraction during endothelin exposure in coronary arteries were then performed. Endothelin (10(-9) to 10(-7) M) was administered either cumulatively or as a single concentration. Ex significantly attenuated the Ca(m) response to 10(-9) and 10(-8) M endothelin. Developed tension was significantly diminished at 10(-8) M endothelin in Ex pigs, producing a rightward shift in the concentration-developed tension response. Attenuated Ca(m) and contractile response to 10(-8) M endothelin were present after Ex whether endothelin was applied cumulatively or as a single concentration. The developed tension-Ca(m) relationship showed an increased Ca(m) sensitivity of contraction with Ex. Endothelin (10(-8) M)-induced Ca2+ influx, estimated by Ba2+ influx in low-Na+ solution, was increased threefold in coronary arteries from Ex pigs. The decreased Ca(m) in the presence of increased divalent cation (i.e., Ca2+) influx during 10(-8) M endothelin suggests a greatly enhanced sarcolemmal Ca2+ cycling in coronary arteries from Ex pigs.     

Pseudocoarctation of the abdominal aorta

Cystic insulinomas are rare, with only three cases having been reported in the literature. It is not difficult to determine the site of such neoplasms, as cystic insulinomas are usually 4-10 cm in diameter. We report a patient with a histologically confirmed cystic insulinoma. This case is unique because of the small size (1.3 cm) of the tumor. Arterial stimulation venous sampling was useful for localizing and distinguishing this tumor from other pancreatic lesions.     

Coarctation of the abdominal aorta

HISTORY AND FINDINGS: When a 27-year-old woman went to her general practitioner with symptoms of acute gastroenteritis he noted a paraumbilical murmur on auscultation. There were no symptoms of intermittent claudication or abdominal angina. All peripheral pulses were easily palpable and bilaterally equal, and there were no vascular murmurs. Physical examination and blood pressure (140/70 mm Hg bilaterally) were normal. INVESTIGATIONS: Biochemical tests gave no indication of inflammatory disease. Oscillography showed a brief decrease in amplitude after muscular exertion, predominantly of the thigh. Posterior tibial systolic pressure was 20 mm Hg lower than radial pressure on the right, 25 mm Hg on the left. Colour Doppler sonography demonstrated elongated and looping coarctation of the abdominal aorta. TREATMENT AND COURSE: As the patient had no symptoms only regular follow-up was indicated. There have been no symptoms for 27 months and no progression of the coarctation. CONCLUSION: In young patients with the described symptoms abdominal coarctation should be included in the differential diagnosis.     

Possible mechanism of captopril induced endothelium-dependent relaxation in isolated rabbit aorta

Natural resistance-associated macrophage protein 1 (NRAMP1) is a putative membrane protein that dominates natural resistance to infection. An NRAMP1-glutathione S-transferase fusion protein was used to test the ability of the NRAMP1 NH2-terminal domain to bind to taxol-stabilized microtubules. Co-sedimentation analysis showed that the fusion protein binds to microtubules. Although the NH2-terminal domain of the NRAMP1 molecule has structural homology with the Pro-rich region of microtubule-associated protein 4 (MAP4), the presence of the MAP4 microtubule-binding domain fragment had little effect on the binding of the fusion protein to microtubules.     

Effects of intense exercise training on endothelium-dependent exercise-induced vasodilatation

To analyse the accuracy of the conversion formulae for estimation of glycohaemoglobin (GHb) measured by different methods, we analysed 210 samples for HbA1c using HPLC. Fifty of these specimens were analysed by micro-column chromatography (MC), 43 by electrophoresis (EP), 50 by IMX system (Abbott Laboratories), 38 by Primus HPLC and 29 by Diamat HPLC. Regression analyses were performed and the equations were used to estimate HbA1c values (HbA1c calc) for the five methods. The 95% limits of agreement between HPLC and the converted results were -1.77 to 1.71%, -1.54 to 1.54%, -0.92 to 0.88%, -0.46 to 0.56%, and -0.39 to 0.41% for MC, EP, IMX, Primus and Diamat equations, respectively. The mean relative errors were 3.4 (-28.2 to 35%), 1.3 (-22.9 to 25.5%), 0.4 (-14.6 to 15.0%), 0.51 (-6.55 to 7.57%), -0.20 (-5.8 to 5.4%), for MC, EP, IMX, Primus and Diamat, respectively. These results show that conversion formulae based on methods that do not measure HbA1c (MC, EP and IMX) are inaccurate and can mask a clinically relevant variation of HbA1c. However, GHb results obtained by HPLC methods could be interchangeably converted with an absolute variation of less than 1%. Converted HbA1c results from non-standardized methods should be interpreted with caution.     

Management of noncalcified aneurysms of the abdominal aorta

Occasionally a previously undiagnosed aneurysm of the abdominal aorta will be found during the course of surgical procedure. When circumstances prevent extending the procedure to include resection and grafting of the aneurysm, the proper placement of silver clips as radiopaque markers may be of substantial benefit in managing this patient until definitive therapy can be instituted.     

Spontaneous rupture of the non-aneurysmal atherosclerotic abdominal aorta

Spontaneous rupture of the non-aneurysmal atherosclerotic aorta is rare. The experience with the patient, the subject of this report, is the sixth reported case. The formation of the false aneurysm in the retroperitoneal area explained why our patient did not have a life-threatening hemorrhage. The obvious treatment is prompt surgical intervention.     

The surgical treatment of aneurysms of the abdominal aorta

The sputum specimens from 1363 patients at the age of 16 to 65 years with nonspecific pulmonary diseases and the pleural exudate specimens from 325 patients were tested for fungi in 1989-1994. The etiological significance of Candida was stated at a concentration of > 10(5) GFU per 1 ml of the sputum. The identification was performed by the routine methods. An increase in the rate of the fungi isolation was studied in the time course of the observation: 15.3 +/- 1.9 per cent in 1989 and 31.6 +/- 3.4 per cent in 1994. The fungi were more frequently isolated from the patients with lung abscesses (38.0 +/- 4.1 per cent of the cases). In the patients with pyothorax the fungi were isolated from the pleural exudate specimens only in 6.8 +/- 1.4 per cent of the cases. The groups of risk of the susceptibility to Candida were revealed. They included patients at the age of 21 to 30 years and above 60. Out of 484 Candida isolates 80.7 per cent belonged to C. albicans, 4.2 per cent to C. tropicalis, 2.1 per cent to C. kefyr and 1.8 per cent to C. krusei. The isolates of C. parapsilosis, C. guillermoudii, C. utilis and C. brumptii were rate. The isolates were highly susceptible to nystatin (91,8 per cent) and lowly susceptible to levorin (35.4 per cent), amphoglucamine (24.7 per cent) and ketokonazol (16.8 per cent).     

Intravenous rupture of arteriosclerotic aneurysms of the abdominal aorta

Intravenous rupture of abdominal aortic aneurysms occurs infrequently but should be considered with the coexistence of severe congestive failure, anasarca, and abdominal bruits. Six patients are presented with four survivors. In only two patients was the diagnosis considered preoperatively without angiography. Two were variants in that thrombus occluded the fistula, thereby negating findings usually manifested clinically. Diagnosis of this type can be made only during operation when copious venous bleeding ensues with evacuation of the aortic thrombus. Careful fluid management and prompt surgery are prerequisites to obtaining a successful outcome. Repair is accomplished easily by suturing the fistula from the aortic aspect, but care is required to avoid dislodgement of thrombus and atherosclerotic debris resulting in pulmonary embolism.     

Surgical treatment of juxtarenal occlusion of the abdominal aorta

Incidence, etiology and clinical course of chronic juxtarenal occlusion of the abdominal aorta have been studied. It was established that this type of lesion among other forms of occlusive disease of the aorto-ileal segment is encountered in 8.1% of patients. Inflammatory diseases of arteries prevailed as an etiologic factor. Diagnosis of this disease should be based on the use of complex up-to-date methods of examination. Roentgeno-contrast aortography in lateral position is of paramount importance in detection of upper level of thrombus spreading in the aorta. Original method of operative procedure used in 20 patients, has been developed with due regards for location of the occlusion, character of lesion of aortic walls and prophylaxis of intraoperative embolic complications. Restoration of blood flow in lower extremities without any intraoperative complications was obtained in all operated patients. In all suffering from symptomatic hypertension normalization of arterial pressure was obtained after the operation. Postoperative mortality rate made up 4.4%. The results obtained confirm high effectiveness of the above surgical treatment of patients with juxtarenal occlusion of the abdominal aorta.     

Rupture of the abdominal aorta following extracorporeal shock-wave lithotripsy

Benzodiazepine use in the treatment of insomnia may cause benzodiazepine dependence, especially in opiate users. The aim of this study was to investigate the sedative-hypnotic effects of amitriptyline in treating opiate-withdrawal insomnia. A total of 27 patients with opiate withdrawal were given either amitriptyline or lorazepam in a randomized double-blind trial. Sleep was assessed by means of the Sleep Evaluation Questionnaire and three insomnia items of the Hamilton Depression Rating Scale. The scores of two sleep measures showed that all aspects of sleep, except for ease of awakening from sleep, in the two treatment groups were not significantly different. In conclusion, apart from the hangover effect, amitriptyline is as effective as lorazepam in the treatment of opiate-withdrawal insomnia.     

Imaging of aneurysms and dissections of the aorta. Part 1--Aneurysms of the abdominal aorta

The authors review the main imaging findings of aneurysms and dissections of the aorta. Based on the experience and imaging techniques available in their institution (Conventional Radiology, Sonography and Computed Tomography), they try to make a decision tree of radiologic procedures in ambulatory and emergency patients. Nowadays, in the majority of situations, these techniques allow the Radiologist to make the correct diagnosis, detect the complications and evaluate the patients in the pre and post-surgical phases. Other imaging techniques not available in their institution, such as Magnetic Resonance Imaging and Aortography, will be mentioned in view of their usefulness in some specific situations.     

Intravascular coagulation in surgical procedures on the abdominal aorta

A prospective study was performed on 32 consecutive patients undergoing elective operations on the abdominal aorta. Dacron prosthetic grafts were used to replace resected abdominal aortic aneurysms or to bypass aorta-iliac occlusive disease. Complete coagulation studies were performed preoperatively, immediately postoperatively and 24 hours postoperatively. Twenty to 30 per cent of the patients had significant postoperative alterations in prothrombin time, partial thromboplastin time and platelet count. Fibrin monomer, fibrin split products and plasminogen were abnormal in 40 to 80 per cent of the patients postoperatively. Results of preoperative studies showed no significant abnormalities. One of the 32 patients had mild clinical evidence of disseminated intravascular coagulation postoperatively, which was treated with 5 units of heparin per kilogram per hour. Results of the study indicate that aortic grafting procedures frequently produce intravascular coagulation, either local or disseminated. In most patients, this is offset by activation of the fibrinolytic system. However, clinically significant sequelae may result, requiring prompt recognition and treatment.     

Exercise training modifies nutrient self-selection in rats

Introduced in 1988, cavernous electromyography and its evolution, single potential analysis of cavernous electrical activity (SPACE), seem to be promising diagnostic methods in the evaluation of erectile dysfunction. The aim of our study was to determine the influence of a centrally disturbed autonomic supply on SPACE recordings. SPACE was performed in 35 male patients with complete and 2 with incomplete spinal cord lesions at a cervical or thoracic level. Simultaneous recording was done with concentric needle electrodes in both cavernous bodies with a frequency range of 0.5 to 100 Hz. All patients underwent a full neurological and urological evaluation, including cystometry. The lesion was cervical in 12 patients and thoracic in 22. Three patients underwent sacral deafferentation and bladder pacemaker implantation. One of 12 patients with cervical and 10 of 22 with thoracic lesions reported full rigid reflexogenic erections, while 3 of 12 patients with cervical lesions were not evaluable due to grounding failure. Of these patients 31 were eligible for our study. No patient had an entirely normal SPACE. Four of 9 patients with cervical and 19 of 22 with thoracic lesions had a normal, silent basic electric (less than 5 mu v.) oscillation, while the remainder had a baseline oscillation of up to 100 mu v. Normal potentials were found in 2 of 9 and 10 of 22 patients, respectively. Low frequency, high amplitude potentials were found in 6 of 9 and 21 of 22 patients, respectively, while low frequency, low amplitude potentials occurred in 8 and 8, respectively, and high frequency potentials occurred in 5 and 1, respectively. Our results show that abnormal autonomic input induces abnormal SPACE findings in patients with (presumably) normal cavernous tissue.