Implantation of novel small-diameter polyurethane vascular prostheses interposed in canine femoral and carotid arteries

OBJECTIVES: The performance of small-diameter (3-5-mm) vascular grafts still poses a challenge in the field of vascular surgery. We present here our preliminary experience with implanting unique small-sized polycarbonate urethane vascular grafts in 7 dogs. MATERIAL AND METHODS: Each animal was implanted with 4 interposition grafts, 2 femoral and 2 carotid. No anti-thrombotic medication was administered. Doppler sonography was performed at 3-month intervals to examine for patency and flow characteristics. Animals were sacrificed electively at 3, 6 and 12 months. RESULTS: At 3 months, all grafts were patent. After 6 months, 3 grafts occluded and at 1 year a further 6 grafts occluded. Hence 9 of 28 grafts occluded (67.9% patency). During the study, no correlation could be established between flow velocity or resistance index and occlusion. Histopathology showed intimal hyperplasia to be the cause of occlusion. CONCLUSIONS: Compared to literature data on small-diameter grafts in the same position, ADIAM's Biomechanical grafts performed clearly better. Compliance data suggest a correlation between elastic compliance and patency.     

Effect of carbon dioxide insufflation on free internal thoracic artery flows: is it a vasodilator?

BACKGROUND: This study was conceived to evaluate the effect of carbon dioxide insufflation on free internal thoracic artery flows. METHODS: We studied 56 consecutive patients who underwent coronary artery bypass grafting in which the left internal thoracic artery was anastomosed to the left anterior descending artery. The first 26 consecutive internal thoracic arteries were harvested as a pedicled graft (group 1), and the next 30 consecutive internal thoracic arteries were dissected by using the carbon dioxide insufflation technique (group 2). The internal thoracic artery harvesting was performed by 2 experienced surgeons by using the same instrumentation and technique. First, free flows of the internal thoracic arteries were registered after distal cutting of the vessel in both groups. After the first measurements, diluted papaverine was sprayed on the internal thoracic artery pedicle only in group 1, and then second measurements were registered after 15 minutes in both groups. Hemodynamic parameters were recorded with each measurement. RESULTS: The first free flow measurement was significantly higher in the carbon dioxide-insufflated internal thoracic arteries (group 2, 60 +/- 32 mL/min; group 1, 28 +/- 19 mL/min; P <.05). Although the second free flow measurement of the carbon dioxide-insufflated group was higher than in group 1, the difference was not statistically significant (68 +/- 46 mL/min vs 53 +/- 32 mL/min; P =.53). CONCLUSIONS: Carbon dioxide insufflation of the internal thoracic artery is an efficient technique to increase the flow and seems to be safe, simple, and reliable. When the internal thoracic artery is harvested in a carbon dioxide-insufflated fashion, arterial spasm and reduced early flow may be avoided, even without vasodilator agents such as papaverine.     

Primary Peritracheal Schwannoma: Report of a Case

Posterior mediastinal tumors of neurogenic origin commonly arise from the sympathetic or intercostal nerves. However, anterior mediastinal tumors rarely originate from the vagus nerve, and primary neurogenic tumors of the trachea are extremely uncommon. A 19-year-old man was admitted to an emergency department in sudden acute respiratory distress. A tracheostomy was performed and he was transferred to our Ear Nose and Throat Department for further investigation. A bronchoscopic biopsy was taken of a mass occupying the tracheal lumen and intraoperative frozen section examination suggested a schwannoma, so tracheal resection was performed. Although rare, primary tracheal schwannoma should be considered in the differential diagnosis of sudden respiratory distress of unknown origin.     

A rare presentation of cardiac hydatid cyst: stroke and acute aortic occlusion

Cardiac involvement in hydatid disease is uncommon. We report a case of a surgically treated ruptured left ventricular hydatid cyst, which presented with acute stroke and was later complicated by distal aortic embolism due to perioperative dislodgement of the germinative membrane.     

Intravenously injected CDP-choline increases blood pressure and reverses hypotension in haemorrhagic shock: effect is mediated by central cholinergic activation

Intravenous (i.v.) administration of cytidine-5′-diphosphate choline (CDP-choline) (100, 250 and 500 mg/kg) increased blood pressure in normal rats and reversed hypotension in haemorrhagic shock. Choline (54 mg/kg; i.v.), at the dose equimolar to 250 mg/kg CDP-choline decreased blood pressure of rats in both conditions and caused the death of all hypotensive animals within 2-5 min. Equimolar dose of cytidine (124 mg/kg; i.v.) did not change cardiovascular parameters. Choline levels in plasma, lateral cerebral ventricle and hypothalamus increased after CDP-choline administration. Intracerebroventricular (i.c.v.) hemicholinium-3 pretreatment (20 μg), greatly attenuated the pressor effect of CDP-choline in both conditions. Atropine pretreatment (10 μg; i.c.v.) did not change the pressor effect of CDP-choline while mecamylamine (50 μg; i.c.v.) abolished the pressor response to drug. Besides, acetylcholine (1 μmol; i.c.v.) produced similar increases in blood pressure in normal and hypotensive conditions to that observed in CDP-choline given rats. CDP-choline (250 mg/kg; i.v.) increased plasma catecholamines and vasopressin levels but not plasma renin activity. Pretreatment of rats with either prazosin (0.5 mg/kg; i.v.) or vasopressin V₁ receptor antagonist, [β-mercapto,β,β-cyclopentamethylenepropionyl¹,O-Me-Tyr²-Arg⁸]vasopressin (10 μg/kg; i.v.), attenuated the pressor response to CDP-choline while simultaneous administration of these antagonists before CDP-choline injection completely blocked the pressor effect. Results show that i.v. CDP-choline increases blood pressure and reverses hypotension in haemorrhagic shock. Activation of central nicotinic cholinergic mechanisms by the increases in plasma and brain choline concentrations appears to be involved in the pressor effect of this drug. Moreover, the increases in plasma catecholamines and vasopressin levels mediate these effects.     

Increased FiO2 improves intrathecal oxygenation during thoracic aortic cross-clamping in pigs

OBJECTIVES: To investigate the effect of 100% oxygen ventilation on cerebrospinal fluid (CSF) oxygenation in 11 pigs during thoracic aortic cross-clamping. DESIGN: An aorto-aortic shunt was used for control of central hemodynamics and study of hypoperfusion by exsanguination. CSF PO2, PCO2 and pH were continuously monitored before and during clamping. The changes in hemodynamic parameters and intrathecal gas tensions in response to variations in proximal mean aortic pressure and fraction of inspired oxygen (FiO2) were recorded. RESULTS: Baseline CSF PO2 decreased from 4.8 +/- 1.9 to 2.6 +/- 2.2 kPa following aortic occlusion. Increasing FiO2 to 1.0 resulted in a significant increase in CSF PO2 to 4.1 +/- 3.0 with a return to 2.7 +/- 2.1 kPa after reducing FiO2 to 0.4 again. The same variations in FiO2 did not induce any significant changes in CSF PO2 during hypotension. CONCLUSION: Increased FiO2 during experimental thoracic aortic cross-clamping with stable proximal arterial pressure helps to maintain CSF PO2, whereas severe hypotension could not be compensated for by hyperoxemia.     

急性淋巴细胞白血病(上)

急性淋巴细胞白血病是淋巴前体细胞异常引起的恶性疾病,儿童与成人均可能发生。儿童发病高峰2～5岁。有效治疗的稳步进展使本病在儿童中的治愈率80％以上,同时为新的治疗方案提供了良机,新方案将保留我们在白血病无病生存病例中获得的治疗经验,同时减轻当前强化治疗方案中的毒副作用。     

A locus for autosomal dominant anterior polar cataract on chromosome 17p

Inherited cataract is a clinically and genetically heterogeneous disease. Here we report the identification of a new locus for an autosomal dominant anterior polar cataract on the short arm of chromosome 17. To map this new locus we performed genetic linkage analysis with microsatellite markers in a four-generation pedigree. After exclusion of seven candidate loci for cataract, we obtained significant positive LOD scores for markers D17S849 (Z = 4.01 / theta = 0.05) and D17S796 (Z = 4.17 / theta = 0.05). Multipoint analysis gave a maximum LOD score of 5.2 (theta max = 0.06) between these two markers. From haplotype analysis, the cataract locus lies in the 13 cM interval between markers D17S849 and D17S796. This study provides the first genetic mapping of an autosomal dominant anterior polar cataract.