Multicenter Randomized Comparison of Xenon and Isoflurane on Left Ventricular Function in Patients Undergoing Elective Surgery

Background: Volatile anesthetics are commonly used for general anesthesia. However, these can induce profound cardiovascular alterations. Xenon is a noble gas with potent anesthetic and analgesic properties. However, it is uncertain whether xenon alters myocardial function. The aim of this study was therefore to investigate left ventricular function during anesthesia with xenon compared with isoflurane.

Methods: The authors performed a randomized multicenter trial to compare xenon with isoflurane with respect to cardiovascular stability and adverse effects in patients without cardiac diseases scheduled for elective surgery. Two hundred fifty-nine patients were enrolled in this trial, of which 252 completed the study according to the protocol. Patients were anesthetized with xenon or isoflurane, respectively. Before administration of the study drugs and at four time points, the effects of both anesthetics on left ventricular function were investigated using transesophageal echocardiography.

Results: Global hemodynamic parameters were significantly altered using isoflurane (P < 0.05 vs. baseline), whereas xenon only decreased heart rate (P < 0.05 vs. baseline). In contrast to xenon, left ventricular end-systolic wall stress decreased significantly in the isoflurane group (P < 0.05 vs. baseline). Velocity of circumferential fiber shortening was decreased significantly in the xenon group but showed a more pronounced reduction during isoflurane administration (P < 0.05 vs. baseline). The contractile index (difference between expected and actually measured velocity of circumferential fiber shortening) as an independent parameter for left ventricular function was significantly decreased after isoflurane (P < 0.0001) but unchanged using xenon.     

Imaging of activated microglia with PET and [11C]PK 11195 in corticobasal degeneration.

Positron emission tomography (PET) using [(11)C]PK 11195, a ligand for peripheral benzodiazepine receptor binding sites, offers the opportunity to image activated microglia in vivo. This tool may therefore be used to display the occurrence of microglial activation in the course of neurodegeneration. A patient with the clinical diagnosis of corticobasal degeneration (CBD) and left-sided symptoms was studied using fluorodeoxyglucose (FDG) and [(11)C]PK 11195 PET. We found a marked right hemispheric hypometabolism and asymmetric microglial activation in corresponding areas of the basal ganglia and right temporal and parietal cortex. [(11)C]PK 11195 PET suggests involvement of microglial activation in the pathogenesis of CBD.     

Evaluation of myocardial metabolism with microdialysis during bypass surgery with cold blood- or Calafiore cardioplegia.

BACKGROUND: For the first time, microdialysis was used to investigate in vivo and online the myocardial metabolism during and after cardiac surgery in patients treated with two different methods of myocardial protection. METHODS: Thirty patients underwent standard CABG with one of two different methods of myocardial protection. The patients were randomised to receive either cold blood (COLD group) or warm modified Calafiore cardioplegia (WARM group). Microdialysis probes were implanted into the myocardium of left ventricular apical region of the heart. Cardioplegia was given antegrade only. Microdialysis measurements were performed at time intervals before, during and 24 h after cardiopulmonary bypass and analysed for glucose, lactate, pyruvate and glycerol. RESULTS: Myocardial lactate concentrations were significantly higher in the WARM group compared with that of the COLD group, while serum lactate was comparable. Glycerol was significantly higher at the end of the clamping time in the WARM group. At the same time the glucose-lactate ratio as a marker of nutritional disorder had significantly lower levels in the WARM group. The cumulative CK-MB release over 24 h was significantly higher in those hearts protected with warm blood. CONCLUSIONS: The oxidative stress measured was significantly higher in patients undergoing CABG using modified Calafiore cardioplegia, whereas the cold cardioplegia minimised the effects of aortic clamping. The results indicate that cold cardioplegia offers superior protection of the heart, in terms of more rapid normalisation of myocardial metabolism. In elective myocardial revascularisation, intermittent antegrade warm blood cardioplegia is a comparable safe method of myocardial protection. However, in patients referring to a long clamping time, advantages of cold cardioplegia for myocardial revascularisation may be magnified.     

Lobucavir-induced proliferative changes in mice

Nucleoside analogues are used in the treatment of viral infections, including those caused by human immunodeficiency virus, cytomegalovirus, and herpes virus. These drugs are beneficial in the treatment of human disease, but are associated with toxicities that often limit their intended therapeutic use, including anemia, neutropenia, peripheral neuropathy, and myopathy. Some of these compounds have been reported to be carcinogenic in rodents. To investigate the carcinogenic potential of lobucavir, a nucleoside analogue, three groups of 60 male and female mice were orally administered lobucavir at daily doses of 10, 50, and 250 mg/kg (males) or 30, 150, and 750 mg/kg (females) over a period of 104 weeks. Two identical groups of 60 male and female mice each served as controls. The morphology and the incidence of neoplasms is described and compared with the tumor spectrum of other nucleoside analogues. Light microscopically, lobucavir-induced neoplastic lesions consisted of upper digestive tract squamous cell neoplasia in males and females; cervical, vaginal, and cutaneous squamous cell neoplasia in females; and Hardarian gland adenomas and adenocarcinomas in male mice. These results suggest that long-term administration of lobucavir causes neoplasia in mice, the spectrum of which resembles that observed after long-term administration of zidovudine or ganciclovir.     

Acutely symptomatic benign mediastinal cysts.

Usually, cystic mediastinal masses are considered as benign. However, the size of the cyst is of importance, chiefly in a closed space such as the superior mediastinum. Rarely a dramatic symptomatology may develop though this was the case in the two patients we describe, who were admitted in the department. In the first case (a parathyroid cyst), the symptoms were due to a thrombosis of the left innominate vein, and in the second case (a thyroid cyst), the severity was dominated by a dramatic compression of the trachea and the vessels. The contribution of computed tomography is nowadays undisputed. It enables the diagnosis of the cystic nature before surgery. The diagnosis can easily be confirmed by percutaneous drainage.     

Cyclosporin A-induced remission of primary membranous glomerulonephritis in a child

Sir, A 4-year-old boy presented with oedema and weight gain of 5kg. There had been no preceding infections, vaccinations ormedication. The family history includes the mothers mesangioproliferativeglomerulonephritis. Laboratory results showed decreased albumin (13 g/l) concentration.Calculated glomerular filtration rate was 125 ml/min/1.73 m²and the     

Percutaneous transluminal rotational atherectomy in the treatment of peripheral vascular disease using a transluminal endatherectomy catheter (TEC): Initial results and angiographic follow-up

Purpose To evaluate the clinical results of percutaneous transluminal rotational atherectomy in the treatment of peripheral vascular disease. Methods Rotational atherectomy was performed in 39 patients aged 39–87 years (mean 66.6 years). A total of 71 lesions (43 stenoses and 28 occlusions) were treated in 40 limbs. Additional balloon angioplasty was required in 54% of lesions. Fifteen patients (37.5%) presented in Fontaine stage II, 10 patients (25%) in Fontaine stage III and 15 patients (37.5%) in Fontaine stage IV. Rotational atherectomy at 750 rpm was carried out over a 0.014-inch guidewire with continuous aspiration into a vacuum, bottle. Follow-up angiography and color flow Doppler examinations were performed in 22 patients (23 limbs) after a mean period of 6 months (range 2–14 months) Results There was one primary technical failure. In 36 of 40 lesions there was a good angiographic result with residual stenoses in less than 30%. In 70 lesions treated by rotational atherectomy, however, 54% showed residual stenoses of 30%–50% and these cases required additional balloon angioplasty. The mean ankle-brachial index improved significantly (p<0.001), from 0.49 before the procedure to 1.01 after the procedure. A single distal embolus, related to primary recanalization, occurred and there were two large inguinal hematomas. Cumulative clinical patency after 6 months was 83.8% and cumulative angiographic patency after 6 months was 79.1%. Conclusion Percutaneous rotational atherectomy is a promising approach for the treatment of chronic peripheral vascular disease. Further prospective, randomized studies are necessary to compare percutaneous transluminal angioplasty with this new technical approach.