Pathophysiology and inflammatory aspects of plaque rupture

We describe the purification and characterisation of a thioredoxin reductase-like disulphide reductase from the ancient protozoan parasite, Giardia duodenalis. This dimeric flavoprotein contains 1 mol FAD per subunit and had an apparent subunit molecular mass of 35 kDa. The purified enzyme catalysed the NADPH-dependent (Km = 8 microM) reduction of 5,5'-dithio-bis(2-nitrobenzoic acid) to thionitrobenzoate and was unable to utilise NADH as an electron donor. The sulphydryl-active compounds, N-ethylmaleimide, sodium arsenite and Zn2+ ions, strongly inhibited the enzyme suggesting that a thiol component forms part of the active site. Purified enzyme was able to utilise a variety of substrates, including cystine and oxidised glutathione, which suggests that it is a broad-range disulphide reductase, probably accounting for the majority of thiol cycling activity in this organism. While the G. duodenalis enzyme does not require an intermediate electron transport protein, analogous to thioredoxin, for activity, we have identified a candidate carrier protein which enhances DTNB turnover six fold, therefore implying that Giardia contains a thioredoxin-like system. Physical, enzymatic and spectral properties of the G. duodenalis disulphide reductase are also consistent with it being a member of the thioredoxin reductase-class of disulphide reductases. Furthermore, the internal amino acid sequence of a tryptic peptide generated from the purified protein was highly homologous with thioredoxin reductases from other sources. This is the first report of a disulphide reductase to be purified from the anaerobic protozoa and explains the so called "glutathione-induced thiol-reductase activity' previously observed in G. duodenalis.     

Coronary artery reoperation

Coronary artery reoperation has been performed in 51 patients (4%) including 5 second reoperations among 1,245 CABGs during past 9 years. There were 40 males and 11 females with a mean age of 58 year old ranging from 19 to 75 year old. Extent of coronary artery disease were; single vessel disease in 2 patients, double vessel disease in 18 patients, triple vessel disease in 22 patients and left main disease in 9 patients. Preoperative ejection fraction ranged from 0.24 to 0.69 (mean 0.48) and 21 patients (41%) showed unstable angina. Interval between primary CABG and reoperation ranged from 1 month to 20 years with a mean of 6 years. There were two groups which had early reoperation at the mean of 6 months (14 patients) and late reoperation at the mean of 9 years (37 patients) after primary CABG. Causes of reoperation varied from graft failure (29 patients), progression of native CAD (2 patients), both of them (19 patients), and incomplete revascularization (1 patient). There were 32 patients who had patent old graft at the time of reoperation. Re-entry approaches used were midsternal in 41 patients and left thoracotomy in 10 patients. The ITA, GEA, IEA and SV grafts were used in 30, 38, 5 and 28 patients, respectively. There were 4 patients who underwent CABG without cardiopulmonary bypass. The mean number of bypass was 2.1 and the mean duration of aortic crossclamp and cardiopulmonary bypass were 63 minutes and 114 minutes, respectively. As a result, there were 4 early and 1 late death. Postoperative angiography revealed that patency rate of ITA, GEA, IEA and SV grafts were 100% (22/22), 97% (30/31), 75% (3/4) and 87% (20/23), respectively. In conclusion, risk of coronary artery reoperation is still high and use of arterial graft is important to obtain high patency rate and low reoperation rate.     

Coronary artery ectasia

Coronary artery ectasia is an uncommon expression of coronary artery atherosclerosis and other diseases. It occurs in about 1.4 percent of the adult population. It is not distinguishable from obstructive coronary artery disease in severity of angina, clinical presentation, electrocardiograms, mortality, or outcome of coronary artery surgery. Although there is debate, treatment is indicated in the form of chronic warfarin anticoagulation to prevent coronary thrombus formation and its sequelae. Aspirin therapy may suffice in asymptomatic individuals.     

Coronary artery disease

Those who have IGT (impaired glucose tolerance) are thought to be highly risky to atherosclerotic coronary artery disease (CAD), probably because of the frequent association with insulin resistance or hyperinsulinemia, obesity or abdominal fat accumulation, hypertriglyceridemia and so on. Whether insulin resistance which is one of the major causes of IGT, following hyperglycemia itself or both is really responsible for CAD is remained to be clarified. Furthermore, IGT is also an apparent candidate for NIDDM in future. Thus, IGT should be intensively treated to prevent or delay the onset of NIDDM and also to minimize the adverse events by atherosclerotic CAD.     

Recognition and management of catheter-induced pulmonary artery rupture

The use of PCR to amplify a specific virA gene fragment serves as a highly specific and sensitive method to detect virulent bacteria of the genus Shigella and enteroinvasive Escherichia coli. Amplification of a 215-bp DNA band was obtained by using isolated genomic DNA of Shigella, individual cells of Shigella dysenteriae, and mayonnaise contaminated with S. dysenteriae. Moreover, a multiplex PCR with specific (virA) and bacterium-restricted (16S ribosomal DNA) primers generated an amplification product of approximately 755 bp for all bacteria tested and an additional 215-bp product for Shigella and enteroinvasive E. coli.     

Postpartum hemorrhage of the uterine artery rupture

Fatty masses, especially solid lipomas, in the paediatric abdomen are very rare. We present such a case, that of an 11-year-old boy who was admitted with abdominal pain and distension. The pre-operative diagnosis of lipoma was suggested by US and CT. The diagnosis of simple lipoma arising in the leaves of the small bowel mesentery, without immature cells, was verified microscopically after the operation. The tumour was enucleated from the mesenterium leaving the intestine intact. We underline the importance of US and CT as pre-operative diagnostic tools.     

Coronary artery fistula after cardiac transplantation

A cardiac transplant recipient with multiple coronary artery fistulae draining into the right ventricle is described. These fistulae presumably resulted from repeated endomyocardial biopsies. The diagnosis of coronary artery fistulae was made at the annual coronary arteriography. The magnitude of the shunt remained small over eight years of follow-up.     

Coronary artery bypass surgery during pregnancy

A 32-year-old woman, in the 22nd week of pregnancy, underwent emergency coronary artery bypass grafting to the left anterior descending artery (LAD). She had suffered an acute myocardial infarction 10 days previously, and continued to suffer from intractable angina pectoris afterwards. Cardiac catheterization revealed spontaneous dissection of the LAD. The left internal mammary artery was used to bypass the LAD, and the operation was performed on a beating heart without the use of cardiopulmonary bypass. The patient's recovery was uneventful, and ultrasound examination and pulse monitoring of the fetus were both normal. She subsequently gave birth to a healthy term baby. To our knowledge this is the second report of coronary artery bypass surgery performed successfully in a pregnant woman. We believe the unique surgical approach avoided the risk of cardiopulmonary bypass to the fetus and placenta.     

Mast cell infiltration in acute coronary syndromes: implications for plaque rupture

The time-course of uterine growth, cell proliferation, and microvascular development was evaluated during the first 72 h after implanting estradiol-17beta (E2) into ovariectomized (OVX) ewes. Uterine fresh weight increased 2.3-fold by 24 h and increased further (3.3-fold) by 48 h. The majority (approximately 75%) of this growth response was associated with tissue growth rather than a change in the tissue dry weight:fresh weight ratio. Both uterine cell number (DNA content) and cell size (RNA:DNA ratio) increased from 0 to 24 h (1.8-fold and 1.7-fold, respectively). Cell proliferation also increased dramatically between 8 h and 24 h after E2 implantation. Endometrial microvascular volume density (percentage of tissue volume occupied by microvessels) increased approximately 1.8-fold by 24 h and then remained constant or declined slightly through 72 h. The total endometrial microvascular volume, however, increased approximately 5-fold from 0 to 24 h and increased further by 72 h. Thus, treatment of OVX ewes with E2 caused a dramatic increase in uterine fresh and dry weights by 24 h, due primarily to hyperplasia and hypertrophy, with only a relatively small change in tissue dry weight:fresh weight ratio. This dramatic uterine growth was associated with a profound increase in endometrial microvascular volume.     

Coronary artery perforation repair using microcoil embolization

An 82-year-old woman undergoing percutaneous transluminal coronary angioplasty experienced perforation of the terminal portion of the left anterior descending coronary artery caused by guidewire trauma. The coronary artery perforation was successfully closed using a vascular occlusion system consisting of individual thrombogenic coils delivered to the site. Coronary artery perforation (CAP) during percutaneous transluminal coronary angioplasty (PTCA) has been reported to occur in less than 1% of cases. The incidence seems to be higher with the new interventional devices, e.g., DCA, TEC, and laser CAP may result in pericardial hemorrhage and cardiac tamponade or a coronary artery fistula to either the left or right ventricle. The management of CAP may include prolonged balloon inflations, reversal of anticoagulation, pericardiocentesis, and emergency surgery. Proximal perforations sometimes can be managed with vein covered stents. We describe another option in the treatment of distal CAP using a vascular occlusion system.     

Coronary atherosclerosis with dual coronary artery fistulas

Coronary artery fistula (CAF) is an uncommon congenital anomaly. Bilateral CAFs, arising from both right and left coronary arteries are rare. Myocardial infarction is by far a less frequent complication of CAF than angina pectoris. Ligation of CAF and coronary artery bypass graft were performed in the treatment of coronary artery stenosis with CAF.     

Coronary artery dissection without acute myocardial infarction

A 57 year-old-man with acute aortic dissection (DeBakey type I) who developed right coronary artery dissection without acute myocardial infarction. He was successful surgically treated and became asymptomatic.