In vitro study of enzymatic degradation of biological tissues fixed by glutaraldehyde or epoxy compound

The study, using bacterial collagenase, was to investigate the changes in characteristics of a collagen-rich tissue, porcine pericardium, fixed by glutaraldehyde or epoxy compound (ethylene glycol diglycidyl ether) during the course of degradation. Fresh porcine pericardium was used as a control. During degradation, the heat released by the reaction of collagenase with a test sample was monitored by a highly sensitive microcalorimeter. Also, the degree of degradation of each test sample was determined by measuring its increment in free amino group content and changes in denaturation temperature and tensile strength. Microcalorimetric analysis of collagenase degradation of fresh, epoxy-fixed, and glutaraldehyde-fixed tissues revealed that the heat released during degradation correlates well with the degree of tissue degraded. The cleaving of peptide bonds in biological tissue by collagenase degradation may increase its free amino group content and reduce its denaturation temperature and tensile strength. It was noted that the fresh tissue cannot resist bacterial collagenase degradation, while the glutaraldehyde-fixed tissue had a relatively better resistance to degradation than its epoxy-fixed counterpart.     

Mechanical properties of a porcine aortic valve fixed with a naturally occurring crosslinking agent.

The study investigates the mechanical properties of porcine aortic valve leaflets fixed with a naturally occurring crosslinking agent, genipin, at distinct pressure heads. Fresh and the glutaraldehyde-fixed counterparts were used as controls. Subsequent to fixation, the changes in leaflet collagen crimps and its surface morphology were investigated by light microscopy and scanning electron microscopy (SEM). Also, the crosslinking characteristics of each studied group were determined by measuring its fixation index and denaturation temperature. In the mechanical testing, tissue strips made from each studied group were examined in both the circumferential and radial directions. Histological and SEM comparisons between fresh porcine aortic valve leaflet and those fixed at medium or high pressure revealed that the following changes may occur: elimination of the natural collagen crimping, and extensive loss of the endothelial layer. The denaturation temperatures of the glutaraldehyde-fixed leaflets were significantly greater than the genipin-fixed leaflets; however, their fixation indices were comparable. Generally, fixation pressure did not affect the crosslinking characteristics of the genipin- and glutaraldehyde-fixed leaflets. It was found that fixation of porcine aortic valves in genipin or glutaraldehyde did not alter the mechanical anisotropy observed in fresh valve leaflets. This indicated that the intramolecular and intermolecular crosslinks introduced into the collagen fibrils during fixation is of secondary importance to the presence of structural and mechanical anisotropy in fresh leaflet. Tissue fixation in genipin or glutaraldehyde may produce distinct crosslinking structures. However, the difference in crosslinking structure between the genipin- and glutaraldehyde-fixed leaflets did not seem to cause any significant discrepancies in their mechanical properties when compared at the same fixation pressure. Nevertheless, regardless of the crosslinking agent used, changes in mechanical properties and ruptured patterns were observed when the valve leaflets were fixed at distinct pressures.     

膝上外侧血管复合组织瓣移植的应用解剖

目的为膝上外侧血管复合组织瓣移植提供解剖学依据.方法50侧红色乳胶灌注的下肢标本,解剖观察膝上外侧动脉的起始、走行、分支、分布及吻合.结果膝上外侧动脉在股骨外侧髁近侧(2.9±0.5)cm处起于动脉,起始处动脉外径(2.2±0.4)mm,主干长(2.6±0.4)cm,至外侧肌间隔处发出上、中、下3支骨膜支分布于股骨下端前外侧.前、后、远3支皮支,分别于股骨外上髁近侧(4.0±0.5)、(5.0±0.5)和(1.5±0.3)cm处进入股下端外侧皮肤,远侧皮支及下肢骨膜支发出交通支与膝关节血管吻合,并有分支分布至髂胫束.[HTH〗结论①膝上外侧动脉可构成皮瓣或骨膜、髂胫束组成的复合组织瓣;②带血管转位可修复膝部软组织缺损;③游离移植修复手、前臂远端或踝足部伴骨、肌腱、皮肤复合组织缺损.     

Anatomic feasibility of creating an inferior epigastric arterio-venous fistula to develop the internal thoracic artery with a view to coronary grafting

Arterio-venous fistulae increase the diameter of their feeding artery. It may be advantageous to increase the diameter of the internal thoracic artery before its use for coronary grafting. A fistula applied directly to the internal thoracic artery may compromise its subsequent use as a coronary graft and is technically difficult and invasive. However, in view of the continuity between the internal thoracic artery and the inferior epigastric artery, it is possible to achieve the same effect by constructing a fistula on the latter. The purpose of this work was to determine, in a cadaveric study, the feasibility of carrying out an arterio-venous fistula on the inferior epigastric artery so as to increase the caliber of the internal thoracic artery before coronary grafting. A morphologic study of the inferior epigastric artery and its vein and their relations as well as the feasibility of such a fistula was carried out on 10 cadavers. The epigastric artery measured 12.35+/-1.2 cm in length. Its diameter decreased from its origin towards it termination from 3.16+/-0.26 cm to 1.76+/-0.18 cm. There was a constant connection between the inferior and superior epigastric arteries. This connection was single in 30% of cases, double in 50% and through an anastomotic plexus of more than two vessels in 20%. The mean number of anastomotic connections was 1.8. The epigastric vein was constant with a diameter of 0.75+/-0.06 mm at its origin and only sufficiently large to carry out a fistula at its termination (2.6+/-0.9 mm). In conclusion, this study indicates that it should be relatively simple to create a fistula between the inferior epigastric artery and either the inferior epigastric vein or the external iliac vein.     

Bilateral origin of the internal thoracic artery from the third part of the subclavian artery a case report

The routine use of the internal thoracic artery (ITA) as a conduit in coronary artery bypass grafting surgery has highlighted the need to appreciate this vessel’s anatomic variations. The usual origin of this vessel is from the first part of the subclavian artery, occasionally from the second and rarely from the third. Henriques-Pino and Prates described a unilateral origin from the third part on the left and Vorster et al on the right. Our cadaveric case report presents an unusual bilateral origin of the ITA arising from the third part of the subclavian artery in a 25-year-old Black South African female. The ITA arose from the ventral aspect, 7.3 cm on the right side and 8.5 cm on the left side from the origin of the subclavian artery, and inclined acutely inferiorly and medially, anterior to the distal attachment of the scalenus anterior m., followed the inner border of the first rib for a short distance and, thereafter, continued its usual course in the thorax. This appears to be the first case report presenting a bilateral origin of the ITA from the third part of the subclavian artery.     

Preparation and antibacterial properties of gelatin grafted with an epoxy silicone quaternary ammonium salt

Gelatin (GE) was modified with epoxy silicone quaternary ammonium salt (EPSiQA) under alkaline conditions (pH 10–11). Silyl and quaternary ammonium groups were linked to gelatin skeleton simultaneously. It was illustrated by XRD and DSC that the short-range order of GE is destroyed and the glass transition temperature (Tg) of GE drops 10 °C after modification. The measured contact angles and surface free energy calculated by Owens–Wendt equation showed that the surface energy of modified gelatin EPSiQA-GE is mainly contributed by the dispersive component of non-polarity silicone groups, the hydrophobility of EPSiQA-GE increases with the increase of grafted silicone units in gelatin. The results of minimum inhibitory concentration indicated that EPSiQA-GE has bactericidal property against Gram-positive bacteria, Gram-negative bacteria and has no antibacterial effect on mold.     

A case of an aberrant internal carotid artery with a persistent stapedial artery: association of hypoplasia of the A1 segment of the anterior cerebral artery

Congenital vascular variants involving the temporal bones are rare. Awareness of these variants is important as they may mimic glomus tumors or complicate middle ear surgery. We present a case of a persistent stapedial artery associated with an aberrant carotid artery in the left temporal bone, which is highlighted in computed tomography imaging findings. We further discuss a possible relationship between hypoplasia of the A1 segment of the anterior cerebral artery and this congenital variant.     

Cadaveric observation of an aberrant left subclavian artery: a possible cause of thoracic outlet syndrome

We report a rare anomaly of the left subclavian artery, coursing through the scalenus anterior muscle, that may cause thoracic outlet syndrome. We also discuss the anatomical basis of the possible diagnostic maneuvers for patients with thoracic outlet syndrome.     

Effects of pretreatment with an indeno-indole compound on lipid peroxidation in the cortex and medulla of rabbit kidneys after ischaemia-reperfusion

The effects of 60 min of ischaemia with or without reoxygenation in vivo or in vitro on lipid peroxidation in cortical and medullary tissue from rabbit kidneys were measured as production of thiobarbituric acid-reactive substances (TBARS). Lipid peroxidation was more pronounced in medullary tissue compared with cortical tissue. The highest TBARS production was found in medullary slices subjected to reoxygenation in vitro immediately after 1 h of ischaemia. Reperfusion in vivo before reoxygenation in vitro attenuated the TBARS formation during subsequent in vitro incubation. Pretreatment of the rabbits with an indeno-indole compound (code name H 290/51) reduced the TBARS formation after 60 min of ischaemia and reoxygenation in vitro towards control values.     

The alternative supply of the pectoralis major flap based medially in cases with previous surgical use of the internal thoracic artery. An anatomical study

In the present study we analyzed the anatomical basis for the use of the pectoralis major muscle based on alternative pedicles in order to evaluate its clinical applications in cases of potential lesion of the internal thoracic artery. The patterns of blood supply depending on the internal thoracic artery, previously dissected for coronary by-pass surgery, were studied in both sides of five embalmed cadavers and five anterior thoracic walls taken from autopsies. The secondary vascular pedicles depending on the internal thoracic artery for the pectoralis major muscle were dissected and injected with physiological saline stained solution in the embalmed cadavers. Moreover, studies of intravascular injection by means of radio-opaque contrast and physiological saline stained solution were carried out in the anterior thoracic walls obtained from clinical autopsies. The results showed that complete injection of the pectoralis major muscle was achieved depending exclusively on the two proximal perforating branches of the two first intercostal spaces, which represented the vascular pedicle for medial transposition of the pectoralis major flap, in cases with previous dissection of the internal thoracic artery for coronary by-pass.     

Physical properties and blood compatibility of surface-modified segmented polyurethane by semi-interpenetrating polymer networks with a phospholipid polymer

Segmented polyurethanes, (SPU)s, are widely used in the biomedical fields because of their excellent mechanical property. However, when blood is in contact with the SPU, non-specific biofouling on the SPU occurs which reduces its mechanical property. To obtain novel blood compatible elastomers, the surface of the SPU was modified with 2-methacryloyloxyethyl phosphorylcholine (MPC) by forming a semi-interpenetrating polymer network (semi-IPN). The SPU film modified by MPC polymer with the semi-IPN (MS-IPN film) was prepared by visible light irradiation of the SPU film in which the monomers were diffused. X-ray photoelectron spectroscopy confirmed that the MPC units were exposed on the MS-IPN film surface. The mechanical properties of the MS-IPN film characterized by tensile testing were similar to those of the SPU film. Platelet adhesion on MS-IPN films was also investigated before and after stress loading to determine the effects of the surface modification on the blood compatibility. Many platelets did adhere on the SPU film before and after stress loading. On the other hand, the MS-IPN film prevented platelet adhesion even after repeated stress loading.     

Treatment of an acute mycotic aneurysm of the common carotid artery with a covered stent-graft

We report herein a case successful endovascular treatment with a stent-graft of a rare case of rapidly growing mycotic aneurysm of the left common carotid artery due to acute bacterial endocarditis after eradication of the infection. Infected mycotic aneurysms of the peripheral vasculature have been considered as a contraindication for stent-graft implantation because of the possibility of microorganism spreading to the stent-graft; however, if there is evidence of complete eradication of microorganism and surgery is not an option, stent-graft implantation can be an effective and safe treatment modality for exclusion of the mycotic aneurysm.     

Theoretical prediction of low-density lipoproteins concentration at the luminal surface of an artery with a multiple bend

To elucidate the mechanisms of localization of atherosclerotic lesions in man, the effects of various physical and hemodynamic factors on transport of atherogenic low-density lipoproteins (LDL) from flowing blood to the wall of an artery with a multiple bend were studied theoretically by means of a computer simulation under the conditions of a steady flow. It was found that due to a semipermeable nature of an arterial wall to plasma, flow-dependent concentration polarization of LDL occurred at the luminal surface of the vessel, creating a region of high LDL concentration distal to the apex of the inner wall of each bend where the flow was locally disturbed by the formation of secondary and recirculation flows and where wall shear stresses were low. The highest surface concentration of LDL occurred distal to the acute second bend where atherosclerotic intimal thickening developed. At a Re₀=500, the values calculated using estimated diffusivities of LDL in whole blood and plasma were respectively 35.1% and 15.6% higher than that in the bulk flow. The results are consistent with our hypothesis that the localization of atherosclerotic lesions results from the flow-dependent concentration polarization of LDL which creates locally a hypercholesterolemic environment even in normocholesterolemic subjects, thus augmenting the uptake of LDL by vascular endothelial cells existing at such sites. © 2002 Biomedical Engineering Society. PAC2002: 8719Uv, 8719Xx, 8714Ee, 8716Uv     

Angiographic demonstration of an aberrant abdominal umbilical artery in a patient with penoscrotal transposition and caudal regression

Penoscrotal transposition (PST) is a rare congenital anomaly characterized by caudal location of the penis with respect to the scrotum. PST may be seen in isolation or associated with caudal regression syndrome. We present a case of an infant born with penoscrotal transposition, bladder agenesis, a solitary dysplastic kidney, and caudal regression. The patient developed anuria and was referred for angiography for preoperative planning for renal transplantation and genital reconstruction. Angiography demonstrated an aberrant abdominal umbilical artery, an anomaly classically associated with sirenomelia but also has been described in caudal regression.     

脂质体包裹尿激酶与D-dimer单抗结合后在血栓模型中靶向溶栓实验

目的： 观察抗纤维蛋白D-dimer的单克隆抗体与包裹溶栓剂尿激酶（UK）的脂质体（Lip）相联接后，在兔腹主动脉血栓模型上靶向溶栓的效果。方法: 用去污剂控制透析法制备Lip、UK-Lip、Ab-UK-Lip。用FeCl3法复制血栓模型，分别从股静脉输入5种不同的药物（①PBS、②大量UK、③Ab/Lip/UK、④Ab/UK-Lip、⑤Ab-UK-Lip），连续观察40 min。结果: 各组血压变化经统计分析得知，Ab-UK-Lip组和UK组效果相似，与其它各组相比较差异均显著（P<0.01），但前者UK用量仅为后者的1/3。结论: 作为UK-Lip的归巢装置，D-dimer单抗在溶栓治疗中有良好的靶向性，Ab-UK-Lip具有良好的应用前景。