MR-guided intravascular catheter manipulation: feasibility of both active and passive tracking in experimental study and initial clinical applications

PURPOSE: To evaluate clinically the feasibility and usefulness of MR-guided intravascular procedures with either active or passive tracking. METHODS: With an active MR tacking system and a 0.2 Tesla open MR imager, real-time and biplane displays of positions of a receive-only coil at the tip of catheters were obtained. For passive tracking, 4 Fr catheters with suitable susceptibility for passive tracking were used. Passive tracking with a 1.5 Tesla MR imager could be performed with parameters of TR 15-50 msec, TE 2.2-2.7 msec, and FA 30 degrees. The temperature of each tracking catheter was monitored in vitro. Clinical trials were performed on six patients (three each). The catheter was introduced to the superior mesenteric artery (SMA) under MR guidance by active or passive tracking to perform MR imaging during arterial portography. RESULTS: The temperature increased minimally. In humans, the SMA and celiac artery could be easily introduced on active tracking. MR-guided manipulation of catheters by active or passive tracking in the model and in dogs' vessels was very successful. Introduction of the catheter into the SMA was successful in two cases of active tracking and in all cases of passive tracking. CONCLUSION: The MR-guided intravascular manipulation of catheters by active or passive tracking may be a clinically feasible method.     

Efficacy of contrast-enhanced MR imaging in cardiomyopathy: an experimental study using Bio14.6 hamsters

RATIONALE AND OBJECTIVES: Myocardial fibrosis was evaluated with magnetic resonance (MR) imaging in Bio14.6 hamsters. MATERIALS AND METHODS: Gated gradient-echo T1-weighted images and spin-echo images with gadopentetate dimeglumine enhancement (0.2 mmol/kg) were obtained. RESULTS: Myocardial enhancement persisted for 13 minutes after administration of gadopentetate dimeglumine, and myocardial signal intensity peaked at 13 minutes on gradient-echo T1-weighted images. The enhanced areas were greater in Bio14.6 hamsters at 25-42 weeks than at 10 weeks. Pathologic data revealed enhancement with inflammation at 10 weeks and fibrosis with vessel proliferation at 25-42 weeks. Pathologic fibrotic change was greater at 32-42 weeks than at 10 weeks. The myocardium of 42-week-old Bio14.6 hamsters showed remarkable contrast enhancement, which continued for 13 minutes. There was no correlation between gadolinium enhancement and pathologic findings in the evaluation of myocardial degeneration and fibrosis. CONCLUSION: Gadolinium-enhanced MR imaging was useful for estimating myocardial fibrotic changes with vessel proliferation and myocardial damage.     

Linear stapling forms improved anastomoses during esophagojejunostomy after a total gastrectomy

BACKGROUND: Circular stapling devices are commonly used to form esophagojejunal anastomoses after total gastrectomy. However, the technique has potential problems with placement of the purse-string suture and insertion of the anvil of the instrument. METHODS: We describe an improved technique for esophagojejunostomy by functional end-to-end anastomosis with linear stapling devices. RESULTS: Three patients with gastric cancer underwent this procedure after total gastrectomy. No anastomotic leakage or clinical evidence of stenosis was encountered. The maximum diameters of the anastomoses, evaluated by radiography with barium at 6 months after surgery, were 3.5 cm and 4.0 cm in 2 patients. Endoscopic examination revealed clear lines of anastomosis with a straight continuity between the distal esophagus and the jejunum. CONCLUSIONS: Our improved technique for esophagojejunostomy by functional end-to-end anastomosis with two linear staplers is a convenient, safe and reliable procedure that is independent of the width of the esophagus and the depth of the esophageal hiatus.     

The relationship of the anterior drawer sign to the shape of the tibial plafond in chronic lateral instability of the ankle

To determine what factors correlate with values for tested anterior drawer (AD) sign, we investigated stress radiographs in 71 patients with severe chronic lateral instability of the ankle as well as 320 normal controls. We found no correlation between AD and talar tilt (TT), but measurement of the anterior tip ratio (ATR) (ATR=tanA x 100) demonstrated a link of ATR with AD (r=0.74, p<0.001). The posterior tip ratio (PTR) (PTR=tanP x 100) was not correlated with AD (r=0.34, p=0.16). The ankle mortise angle (AMA) (the anterior opening of the lateral ankle mortise) was also not correlated with AD (r=0.27, p=0.23). Investigation of 320 normal ankles revealed a mean ATR of 9.1%+/-1.4%. The ATR in patients was 7.6%+/-1.7%, significantly lower than in the control patients. The values in female patients with chronic lateral instabilities were significantly less than the values in the females in the control group. But values for male patients were not different from the control group. Thus the anterior tip of the lateral tibial plafond, as it affects the ATR, may influence instability in anterior drawer function, especially in female patients with chronic lateral ligamentous instability of the ankle.     

Coronary artery bypass grafting for patients with aortoiliac occlusive disease

Harvest of the internal thoracic artery (ITA) in patients with aortoocclusive disease carries a risk of leg ischemia. Staged revascularization of the lower extremities and coronary artery in patients with aortoiliac occlusive disease with collateral vessels to the lower extremities via the ITA is reported. Revascularization of the aortoiliac occlusion prior to coronary artery bypass grafting can be performed in stable patients with appropriate perioperative coronary precautions. In patients with unstable angina and aortoiliac occlusion with collateral vessels to the leg via the ITA, coronary artery bypass grafting should be performed without using the ITA.     

Appearance of rectal varices in extrahepatic portal obstruction after treatment for esophago-gastric varices: a case report

We report a case of rectal varices that developed after endoscopic injection sclerotherapy (EIS) and Hassab's operation for esophageal varices with extrahepatic portal obstruction. A 54-year-old woman was admitted to our hospital in September 1997 for treatment of hematochezia. Emergent colonoscopy revealed tortuous rectal varices with a white plug. Angiography revealed that rectal varices were provided with backward blood flow by the inferior mesenteric vein due to extrahepatic portal obstruction. In this case, previous treatment, EIS and Hassab's operation, for esophago-gastric varices might have inhibited the development of collaterals apart from surface of gastrointestinal tract, such as para-esophageal collateral veins or spleno-renal shunt. Since the thrombus in the extrahepatic portal vein causes strong pressure on inferior mesenteric vein which is connected to the inferior vena cava via the inferior rectal vein, rectal varices might be developed. In this case, it was considered that rectal varices were not treated enough by endoscopic therapy because of regurgitant hyper blood flow against portal venous pressure. Therefore, rectal transection was performed. After the treatment, the patient suffered no further episodes of bleeding from rectal varices.     

Appendicitis caused by caecal carcinoma: report of a case

Appendicitis can rarely occur in association with carcinoma of the caecum, particularly in elderly patients. We report a case of acute appendicitis provoked by an adenocarcinoma of the caecum which obstructs the lumen of the appendix in a 58-year-old man. The patient underwent an ileocaecal resection with lymph node dissection. The difficulties of identifying a small tumor at laparotomy and the implication for optimal treatment are emphasized.     

Interactions of two major metabolites of prasugrel, a thienopyridine antiplatelet agent, with the cytochromes P450.

The biotransformation of prasugrel to R-138727 (2-[1-2-cyclopropyl-1-(2-fluorophenyl)-2-oxoethyl]-4-mercapto-3-piperidinylidene]acetic acid) involves rapid deesterification to R-95913 (2-[2-oxo-6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl]-1-cyclopropyl-2-(2-fluorophenyl)ethanone) followed by cytochrome P450 (P450)-mediated formation of R-138727, the metabolite responsible for platelet aggregation. For identification of the P450s responsible for the formation of the active metabolite, the current studies were conducted with R-95913 as the substrate. Incubations required supplementation with reduced glutathione. Hyperbolic kinetics (K(m) 21-30 microM), consistent with a single enzyme predominating, were observed after incubations with human liver microsomes. Correlation analyses revealed a strong relationship between R-138727 formation and CYP3A-mediated midazolam 1'-hydroxylation (r(2) = 0.98; p < 0.001) in a bank of characterized human liver microsomal samples. The human lymphoblast-expressed enzymes capable of forming R-138727, in rank order of rates, were CYP3A4>CYP2B6>CYP2C19 approximately CYP2C9>CYP2D6. A monoclonal antibody to CYP2B6 and the CYP3A inhibitor ketoconazole substantially inhibited R-138727 formation, whereas inhibitors of CYP2C9 (sulfaphenazole) and CYP2C19 (omeprazole) did not. Scaling of in vitro intrinsic clearance values from expressed enzymes to the whole liver using a relative abundance approach indicated that either CYP3A4 alone or CYP3A4 and CYP2B6 are the major contributors to R-138727 formation. R-95913 and R-138727 were also examined for their ability to inhibit metabolism mediated by five P450s. R-138727 did not inhibit the P450s tested. In vitro, R-95913 inhibited CYP2C9, CYP2C19, CYP2D6, and CYP3A, with K(i) values ranging from 7.2 microM to 82 microM, but did not inhibit CYP1A2. These K(i) values exceed circulating concentrations in humans by 3.8- to 43-fold. Therefore, neither R-95913 nor R-138727 is expected to substantially inhibit the P450-mediated metabolism of coadministered drugs.     

Continuous monitoring of circadian variations in intraocular pressure by telemetry system throughout a 12-week treatment with timolol maleate in rabbits.

AIM: The aim of this study was to examine the effect of a 12-week treatment with two formulations of timolol maleate on the amplitude of the circadian fluctuation in intraocular pressure (IOP). METHODS: Conscious Japanese White rabbits housed under a controlled 12-hour light-dark cycle were used. IOP was measured by a telemetry system. Each animal was treated topically for 12 weeks with 0.5% timolol solution (TM) twice-daily, 0.5% timolol gel-forming solution (TM-gel) once-daily, or saline twice-daily, and the circadian variation in IOP was measured every week. RESULTS: Administration of TM or TM-gel did not change IOP in the light phase, but significantly reduced it in the dark phase in each of the 12 weeks. The IOP reductions at 2 h after administration in the TM and TM-gel groups over the 12 weeks were, respectively, 3.6 +/- 0.3 mmHg and 3.4 +/- 0.2 mmHg versus the Saline group. The amplitudes of the circadian fluctuations in IOP in the TM group in weeks 3, 6, and 12 were 15%, 15%, and 18% smaller than those in the Saline group, while the corresponding values for the TM-gel group were 18%, 16%, and 19%, respectively. CONCLUSIONS: TM-gel administered once-daily was as effective at lowering IOP as TM administrated twice-daily over the 12-week experimental period. This study reveals that, in rabbits, both formulations of the timolol maleate induced significant IOP reductions in the dark phase and decreased the amplitudes of the circadian fluctuations in IOP for 12 successive weeks.     

Reis-Bücklers角膜营养不良患者TGFBI基因突变

目的　探讨中国Reis Bücklers角膜营养不良患者的TGFBI基因的突变特征及其与临床表现的关系。方法　对于彼此无亲缘关系的两家系 10例患者及其家族中 2名正常成员进行基因分析。采取外周血 10ml,制备外周血白细胞基因组DNA,应用合成的特异性引物,聚合酶链反应(PCR)分别扩增TGFBI基因的第 4、12外显子,将基因产物进行直接测序,分析相应基因序列。结果两家系均呈现常染色体显性遗传。临床上表现为角膜上皮下及前弹力膜中细小的颗粒状混浊,随年龄增长而逐渐融合、扩大呈地图样外观,符合Reis Bücklers角膜营养不良地图型的诊断。基因序列分析呈现TGFBI基因第 124密码子第二个碱基G→T碱基点突变,导致精氨酸转变为亮氨酸(R124L)。结论　中国Reis Bücklers角膜营养不良患者两家系均呈现R124L基因突变,表现为Reis Bücklers角膜营养不良地图型改变。基因分析将为疾病的确诊提供可靠依据。