Stroke in surgery of the arteriosclerotic descending thoracic aortic aneurysms: influence of cross-clamping technique of the aorta.

OBJECTIVE: The risk of stroke caused by dislodgment of loose atheromatous plaque or mural emboli is increased by cross-clamping of the aorta. Some patients undergo descending thoracic aortic aneurysm repair with proximal aortic cross-clamping between the left common carotid artery and the left subclavian artery. The objective of this study was to determine the influence of proximal aortic cross-clamping in arteriosclerotic aneurysm or dissecting aneurysm repair. METHODS: Between May 1984 and May 2003, 81 patients underwent elective surgery for distal arch or descending aortic aneurysm repair with proximal aortic cross-clamping between the left common carotid artery and the left subclavian artery. To evaluate the influence of the proximal aortic cross-clamping, patients were divided into two groups: patients who had undergone arteriosclerotic aneurysm repair (group I, n=25) and patients who had undergone dissecting aneurysm repair (group II, n=56). RESULTS: Eight (9.9%) of the 81 patients had a stroke. Six strokes occurred in operations for arteriosclerotic aneurysm repair group I and two strokes occurred in operations for dissecting aneurysm repair group II (24 vs 3.6%; p=0.009). In-hospital mortality rates were 12% in group I and 8.9% in group II (p=0.70). Major postoperative complications included renal failure requiring hemodialysis (in 4.2% of the patients in group I and in 8.3% of the patients in group II, p=0.99) and pulmonary complication (in 20% of the patients in group I and in 16% of the patients in group II, p=0.67). CONCLUSION: Cross-clamping between head vessels should be avoided if at all possible when operating on patients who have arteriosclerotic descending thoracic aneurysms.     

Our Distal Aortic Perfusion System in Descending Thoracic and Thoracoabdominal Aortic Aneurysm Repairs

Abstract: We have used heparin-bonded partial cardio-pulmonary bypass to support distal aortic circulation during aortic cross-clamping. However, there were no cardiotomy reservoirs with fully reliable thromboresistance. To resolve this problem, a short-acting anticoagulant (nafamostat mesilate) was added into a cardiotomy reservoir. The present study was designed to evaluate the efficacy of our distal perfusion system. From May 1995 through the end of May 1996, 27 patients underwent descending thoracic and thoracoabdominal aortic aneurysm repairs with this adjunct, 4 being excluded from the experiment. Twenty patients who had undergone conventional partial cardiopulmonary bypass were defined as the control group. There were no significant differences between the 2 groups in the morbidity, mortality, gas transfer, or transfusion requirements despite the fact that more complicated surgical procedures (shown by a two-fold increase in the prevalence of reoperation) were required in the group that had received the current distal perfusion adjunct. the heparin-bonded group. In conclusion, our perfusion system is very effective for descending thoracic and thoracoabdominal aortic aneurysm repairs.     

Kanamycin ototoxicity in glutamate transporter knockout mice

Glutamate-aspartate transporter (GLAST), a powerful glutamate uptake system, removes released glutamate from the synaptic cleft and facilitates the re-use of glutamate as a neurotransmitter recycling system. Aminoglycoside-induced hearing loss is mediated via a glutamate excitotoxic process. We investigated the effect of aminoglycoside ototoxicity in GLAST knockout mice using the recorded auditory brainstem response (ABR) and number of hair cells in the cochlea. Kanamycin (100 mg/mL) was injected directly into the posterior semicircular canal of mice. Before the kanamycin treatment, there was no difference in the ABR threshold average between the wild-type and knockout mice. Kanamycin injection aggravated the ABR threshold in the GLAST knockout mice compared with the wild-type mice, and the IHC degeneration was more severe in the GLAST knockout mice. These findings suggest that GLAST plays an important role in preventing the degeneration of inner hair cells in aminoglycoside ototoxicity.     

Radioresponse of Thymomas Verified with Histologic Response

Patterns of radiologic response of 10 thymomas treated by preoperative radiotherapy (RT) (18-20 Gy/2 weeks) were determined in conjunction with histologic response. Changes in tumor volume were evaluated with CT scans obtained 5 to 36 days before and 14 to 24 days after the initiation of RT and before surgery. The extent of tumor volume reduction (TR) varied widely (40-78%), while the mean daily volume decrement expressed as a percentage of the pre-RT tumor volume correlated significantly with the pre-RT tumor volume. Histologically, the tumors, all of which were resected 17 to 33 days after RT initiation, generally consisted of predominant fibrous tissues, rare necrotic foci, and few epithelial cells. The TR did not correlate with pre-RT tumor volume, observation period, histologic subtype, or quantity of remaining epithelial cells. The TR of thymomas does not predict RT impact on tumor cells but does reflect the quantity of inherent tumor stroma.     

First case of a bloodstream infection caused by the genus Brachybacterium

An 83-year-old previously self-sufficient man was referred to our hospital for a fever, severe tenderness over the lumbar spine, and elevated C-reactive protein levels. Computed tomography revealed fluid collection in the intervertebral space of L3/4. Gram-positive, short rod-shaped bacteria were isolated from two sets of blood cultures. A 16S rRNA sequence analysis of an isolate showed a similarity of 98.1% to the nearest type strain Brachybacterium squillarum JCM 16464^T. Biochemical characteristics of the presently isolated strain differed from those of the most closely related species of the genus Brachybacterium. The patient was successfully discharged on day 73 of admission with antimicrobial therapies and showed no recurrence during outpatient visits. Brachybacterium spp. have mainly been isolated from the environment, and human Brachybacterium infections have rarely been documented to date. To our knowledge, this is the first clinical isolation of Brachybacterium sp. as a causative pathogen of bloodstream infection.     

Impact of prior lamivudine use on the antiviral efficacy and development of resistance to entecavir in chronic hepatitis B patients

Background/Aims

To determine the efficacies of entecavir (ETV) in nucleos(t)ide analogue (NA)-naïve chronic hepatitis B (CHB) patients and in those with prior lamivudine (LAM) use who did not develop resistance.

Methods

We retrospectively enrolled 337 patients with CHB who were treated with ETV (0.5 mg daily) for at least 30 months. The study included 270 (80.1%) NA-naïve patients and 67 (19.9%) LAM-use patients. Ten of the LAM-use patients were refractory to LAM therapy without developing resistance.

Results

Genotypic resistance to ETV developed more frequently in the LAM-use group (13.1%) than in the NA-naïve group (2.6%) at 60 months (P=0.009). In subgroup analysis, after excluding the 10 patients who were refractory to LAM therapy, the cumulative probability of ETV resistance did not differ significantly between the two groups (P=0.149). Prior LAM refractoriness and a higher hepatitis B virus DNA level at month 12 were independent predictive factors for the development of ETV resistance.

Conclusions

ETV resistance developed more frequently in LAM-use patients with CHB. However, prior LAM use without refractoriness did not affect the development of ETV resistance. The serum hepatitis B virus DNA level at month 12 was a major predictor for the development of ETV resistance.