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.     

Morphologic and functional changes in nontumorous liver tissue after radiofrequency ablation in an in vivo model: comparison of 18F-FDG PET/CT, MRI, ultrasound, and CT.

Rimlike contrast enhancement on morphologic imaging and increased tracer uptake on (18)F-FDG PET in the periphery of the necrosis can hamper differentiation of residual tumor from regenerative tissue after radiofrequency ablation of liver lesions. This study used MRI, CT, ultrasound, and (18)F-FDG PET/CT to assess the typical appearance of lesions in nontumorous animal liver tissue after radiofrequency ablation. METHODS: Lesions were created by radiofrequency ablation of normal liver parenchyma in 21 minipigs. Follow-up was performed by 3 contrast-enhanced morphologic modalities-MRI, CT, and ultrasound-and by (18)F-FDG PET/CT immediately, 3 and 10 d, and 1, 2, 3, and 6 mo after radiofrequency ablation. Images were evaluated qualitatively for areas of increased enhancement and regions of elevated tracer uptake. Furthermore, all images were assessed quantitatively by determination of ratios comparing enhancement/tracer uptake in the periphery of the necrosis with enhancement/tracer uptake in normal liver parenchyma. Imaging findings were compared with histopathology findings. RESULTS: Immediately after radiofrequency ablation, no increase in (18)F-FDG uptake was visible, whereas elevated enhancement was noticed in the periphery of the necrosis on all morphologic imaging procedures. At further follow-up, an area of rimlike increase in (18)F-FDG uptake surrounding the necrosis was detected on PET/CT. The rimlike pattern of increased enhancement in the arterial phase was present for all liver lesions on CT, MRI, and ultrasound, especially between day 3 and month 1 after the radiofrequency ablation. Both elevated glucose metabolism and enhancement persisted for 6 mo postinterventionally. Histologic examination showed a hemorrhagic border converting into a regeneration capsule. CONCLUSION: If performed immediately after radiofrequency ablation, (18)F-FDG PET/CT probably has benefits over those of morphologic imaging procedures when assessing liver tissue for residual tumor. Later follow-up may be hampered by visualization of peripheral hyperperfusion and tissue regeneration. Further studies on a patient population are essential.     

Phage-displayed recombinant single-chain antibody fragments with high affinity for cholesteryl ester transfer protein (CETP): cDNA cloning, characterization and CETP quantification.

Cholesteryl ester transfer protein (CETP) greatly affects the metabolism of all lipoprotein classes including low-density lipoprotein (LDL) and high-density lipoprotein (HDL), both known to constitute powerful risk factors for coronary artery disease (CAD). We now report the successful first cloning and characterization of single-chain antibody fragments specific for CETP. A recombinant phage display library was generated using spleen mRNA isolated from BALB/c mice that had been immunized with highly purified CETP. Screening of the library yielded two single-chain antibody fragments with high affinity for CETP, termed 1CL8 and 1CL10, displaying respective KD values of 4.36 x 10(-9) M and 4.64 x 10(-9) M as determined by affinity sensor technology. Amino acid sequence comparison indicated the complementarity-determining regions of the respective heavy chains to be responsible for CETP high affinity binding. Fragment 1CL8 was successfully employed in clinical chemical quantification systems that uncovered an association in humans between plasma CETP concentration and total body fat mass (r=0.50, p<0.002). Because of the demonstrated superb CETP capturing capacity, combined with high binding affinity to CETP, ready access and unlimited supply, 1CL8 and 1CL10 are expected to prove powerful tools for studies on the role of CETP in atherogenesis.     

Case report: Fatal hepatic failure after aortic valve replacement and sevoflurane exposure

PURPOSE: To report a case of lethal hepatotoxicity possibly caused by sevoflurane. CLINICAL FEATURES: A 76-yr-old woman with a history of four previous minor surgical procedures developed acute liver failure after general anesthesia with sevoflurane, sufentanil and propofol for aortic valve replacement. After an uneventful procedure the patient was extubated 4.5 hr after surgery. On the second postoperative day, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) increased. On the third postoperative day liver failure occurred, ALT peaked at 10504 UxL(-1) and AST at 15516 UxL(-1), and coagulopathy with an international normalized ratio of 4.6 developed. Liver transplantation was considered but rejected as a therapeutic option. The patient died three days after the operation in multiple organ failure triggered by hepatic failure. Other possible causes for liver failure were excluded. CONCLUSIONS: Sevoflurane hepatitis as a cause for liver failure may be implicated in this patient undergoing valve surgery. Unlike other halogenated anesthetic drugs, sevoflurane is not metabolized to hepatotoxic trifluoroacetyl proteins. However, compound A may react with proteins and may be transformed into antigenic material. We suggest that all halogenated anesthetics may be implicated with acute liver injury.     

Fusion of bone marrow-derived stem cells with cardiomyocytes in a heterologous in vitro model.

OBJECTIVE: Recent studies have demonstrated that transplanted bone marrow-derived stem cells (BMCs) possess a broad differentiation potential and are able to form new cardiomyocytes. However, the identity of BMCs as true cardiomyocytes is still ambiguous. Therefore, we investigated the fate of transplanted fluorescence labeled BMCs and cardiomyocytes in co-culture. METHODS: For cell tracking we used two different fluorescent probes, Vybrant/DiO and Vybrant/DiI. BMCs were taken from human sternal marrow, purified using a Ficoll-gradient-centrifugation, treated with 5-azacytidine and stained with Vybrant/DiO. Furthermore, isolated spontaneous beating cardiomyocytes of neonatal rats (CM) were labeled with Vybrant/DiI. Thereafter, the BMCs were transplanted into CM-cultures and investigated on day 1, 4, 7, 14 and 28 using two-color fluorescence phenotyping by laser-scanning-cytometry (LSC). Two-color positive cells were harvested by patch-clamp technique and beta-MHC mRNA expression was analyzed by single-cell PCR. RESULTS: Two different morphological phenotypes were observed by LSC. First, isolated DiO labeled BMCs without contact or with direct cell contact to DiI labeled CMs. Second, some BMCs and CMs were double positive for DiO/DiI spontaneously forming hybrids. This population increased by 18% from day 1 to 4 and decreased only slightly until day 28. Additionally, few two-color positive cell formations expressed both human and rat specific beta-MHC mRNA as well as only human beta-MHC mRNA indicating that cell-fusion and transdifferentiation has occurred. CONCLUSION: These observations provide in vitro evidence for spontaneous cell fusion and transdifferentiation of BMCs in co-culture, raising the possibility that the observed phenomenons may contribute to development or maintenance of these cell types.     

Meta-analysis of randomized controlled comparisons of psychopharmacological and psychological treatments for anxiety disorders.

BACKGROUND: A number of meta-analyses have led to contradictory results regarding the efficacy of the psychological and pharmacological treatment of anxiety disorders. The main reasons for these inconsistent results seem to be the inclusion of heterogeneous studies and influences of selection biases. We performed a meta-analysis, which only included studies using a direct comparison of pharmacological, psychological, or combined treatments. METHOD: Sixteen studies on panic disorder, six studies on social anxiety disorder, and two studies on generalized anxiety disorder have been analyzed. Effect sizes for differences between the different treatment modalities were calculated. Also, the effect sizes of the pre-post differences were calculated. RESULTS: Pharmacological treatment, cognitive-behavioural treatment, and the combination of both treatment modalities all led to substantial improvement between pre- and post-treatment. Combined pharmacological and psychological treatment was superior to the monotherapies for panic disorder. For social anxiety disorder, there is only preliminary support for combined treatment. Due to lack of sufficient data, no final conclusions can be drawn for generalized anxiety disorder. CONCLUSIONS: While drug treatment and CBT showed equal efficacy, only in panic disorder the combination of pharmacological and psychological treatment was superior to either treatment alone. For the other anxiety disorders, the evidence for greater efficacy of combination treatment is still not sufficient due to lack of studies.     

Surgical treatment of multiple knee ligament injuries in 44 patients: 2–8 years follow-up results

The purpose of the study was to evaluate the mid-term results of surgical treatment in different groups of patients with multiple knee ligament injuries. Review of our patients’ records revealed that 48 acute and chronic patients were surgically treated for combined knee injury. Due to severe capsular damage in these injuries, open techniques were used. In our treatment protocol, avulsed ligaments and tears of the posterolateral and posteromedial corner were repaired if possible, whereas midsubstance tears of cruciate ligaments and chronic cases were reconstructed with autografts. Postoperatively, an accelerated program of rehabilitation was introduced, aiming to progressively mobilize the joint and improve muscle endurance. For the follow-up evaluation we designed a protocol composed of two parts. In the first part, anatomical lesions were recorded and in the second part, clinical evaluation was performed using the Lysholm score, the Tegner rating system, the IKDC evaluation form, and the KT1000. Student’s t tests and chi-square tests were used for data analysis. Forty-eight patients (mean age 28.6±11.9 years; 41 males) were classified according to the specific anatomical structures involved. Group A included 12 anterior cruciate ligament (ACL) and medial structure injuries, group B included 11 ACL or posterior cruciate ligament (PCL) ruptures combined with posterolateral injuries, and group C consisted of 25 knee dislocations (ACL and PCL ruptures which might be combined with damage of the collateral ligaments). Thirty-eight patients were surgically treated during the acute phase and ten patients were treated chronically. Forty-four patients (91.6%) were followed up at a mean of 51.3±29.9 months. Average Lysholm score was 87±12.3; average Tegner score was 5.09±2.19 before accident and 4.34±2.12 in re-examination; IKDC score was A in 10 cases, B in 22, C in 6, and D in 6. The mean range of motion was 129.9°±12.5°. The average loss of extension and flexion were 1.6°±2.5° and 7.6°±7.9°, respectively. The side-to-side difference in corrected anterior and posterior translation in quadriceps neutral angle and in anterior translation in 30° angle was <3 mm for about 65% of our patients. Surgical treatment of multiple knee ligament injuries, using autografts, provided satisfactory stability, range of motion, and subjective functional results. However, despite the improvement of the quality of life, the preinjury patients’ activity level was not fully obtained in re-examination. Patients underwent surgical treatment during the acute phase had better scores in several points, but finally there was no statistical significance between acute and chronic patients. Moreover, no statistically significant differences were observed among the groups with specific damaged anatomical structures.     

Arthroscopic treatment of synovial chondromatosis of the ankle

A 34-year-old male soccer player with chronic right ankle dysfunction and a history of repeated ankle joint injuries is presented. Imaging studies revealed synovial chondromatosis of the ankle joint. Arthroscopic partial synovectomy was performed and more than 20 loose bodies were excised. Four months postoperatively the patient was asymptomatic and has returned to his previous level of sport activities. At the latest follow-up, 2 years after the initial diagnosis there is no local recurrence of the disease. Arthroscopy is a minimal invasive surgical technique, with satisfactory results in the treatment of synovial chondromatosis of the ankle joint.