Expandable metallic stent treatment for malignant colorectal strictures

Four patients were treated by placement of an expandable metallic stent (two Gianturco Z-stents, two Ultraflex stents) for malignant colorectal strictures. All four patients were able to defecate after stent placement. Stent migration was recognized in one patient. Two patients suffered from tenesmus after stent placement.     

Selective ablation of porcine and rabbit liver tissue using radiofrequency: preclinical study

Temperature changes and their distribution induced by 13.56-MHz radiofrequency (RF) heating of agar phantom and porcine and rabbit liver were investigated. It was possible to produce selective local heating of approximately 50 degrees C in the RF field of 2 x 2 x 2 cm(3) of the pig or rabbit liver. Coagulation necrosis after heating became pronounced and the margin between the coagulated lesion and normal tissue became clearer with time. Within 1 week after RF heating at 50 degrees C for 20 min, the coagulated area was replaced selectively and totally by necrotic tissue.     

3D TOF turbo MR angiography for intracranial arteries: phantom and clinical studies

This work investigated whether turbo magnetic resonance angiography (MRA) can replace conventional MRA in screening examination of intracranial arteries. A phantom was used to evaluate the effect of the zero-filling interpolation (ZFI) technique on spatial resolution and partial volume effect. Thirty-one consecutive patients underwent both turbo MRA with a slice thickness of 0.7 mm (data were measured as 1.33 mm sections) and conventional MRA with 1.0 mm sections. In the phantom studies, ZFI did not improve the spatial resolution, but the partial volume effect was somewhat reduced. In the clinical evaluation, turbo MRA showed better signal-to-noise and contrast-to-noise ratios of the intracranial major vessels than conventional MRA. The lesions included cerebral aneurysms less than 3 mm in diameter, occlusive vascular disease, arteriovenous malformations, and arteriovenous fistulas. These were all depicted on both turbo MRA and conventional MRA. Turbo MRA is a useful screening procedure because of its capability of delineating lesions in approximately half the usual imaging time. J. Magn. Reson. Imaging 1999;10:939-944.     

The effects of combined sympathetic block and intravascular infusion of prostaglandin E1 on brachial arterial blood flow in dogs

We compared the effects of stellate ganglion block (SGB) with those of SGB combined with an intravascular infusion of prostaglandin E1 (PGE1) on brachial arterial blood flow (BABF) in 24 mongrel dogs. The experimental protocol was designed so that the dogs received one of the following: SGB with 0.5% mepivacaine 1.0 mL (n = 8); combined SGB and IV infusion of PGE1 at a rate of 150 ng x kg(-1) x min(-1) for 10 min (n = 8); or combined SGB and intraarterial (IA) infusion of PGE1 at a rate of 0.1 ng x kg(-1) x min(-1) for 10 min (n = 8). BABF increased significantly in all groups and reached a maximum of 67% 10 min after SGB, 124% with the combined SGB and IV infusion of PGE1, and 117% with the combined SGB and IA infusion of PGE1. We conclude that combined SGB and IV or IA infusion of PGE1 increases BABF significantly compared with SGB alone. IMPLICATIONS: Combined stellate ganglion block and intraarterial or IV infusion of prostaglandin E1 increases brachial arterial blood flow significantly compared with stellate ganglion block alone.     

Anesthetic management for urgent endoscopy in a child with heterotopic liver transplant

A 6-year-old boy with heterotopic liver transplant underwent urgent endoscopy under general anesthesia because of bloody stool. He was taking cyclosporin as an immunosuppressant. His hepatic function was normal and no side effects of cyclosporin were observed. Preoperative blood transfusion was performed because of severe anemia. Anesthesia was induced with midazolam 2 mg, ketamine 20 mg and fentanyl 0.05 mg, and maintained with addition of midazolam and ketamine. We did not use any inhalation anesthetics to avoid postoperative hepatic dysfunction. The endoscopy was successfully performed and the postoperative course was uneventful. We conclude that preanesthetic evaluation of immunosuppressant state and the hepatic function of transplanted liver is important for anesthetic management of a patient with heterotopic liver transplant.     

Prolonged antinociceptive effect of poly (DL-lactic acid)-fentanyl composites after their intrathecal injection in rats

We synthesized poly (DL-lactic acid)-fentanyl composites and compared the duration of analgesia after the administration of a single intrathecal dose of these agents in rats. The drug was injected with an intrathecal catheter into the intrathecal space. Fentanyl composites or plain fentanyl in doses of 2.5 or 25 micrograms were administered, respectively. Animals were then tested for analgesia using the tail-flick test. The release rate of fentanyl from fentanyl composites in vitro was also evaluated. The antinociceptive effect of fentanyl composites (25 micrograms) was significantly longer than that of plain fentanyl. Administration of poly (DL-lactic acid) alone did not induce the antinociceptive effect. Four of 7 animals given plain fentanyl (25 micrograms) exhibited temporary respiratory depression, but none of the animals given fentanyl composites showed this response. In vitro experiments demonstrated a slow release of fentanyl from the fentanyl composites. We conclude that the antinociceptive effect of fentanyl can be prolonged when administered as a poly (DL-lactic acid)-fentanyl composite in the intrathecal space with decreased systemic side effects compared with the plain formulation.     

Etidronate (EHDP) Inhibits Osteoclastic-Bone Resorption, Promotes Apoptosis and Disrupts Actin Rings in Isolate-Mature Osteoclasts

Bisphosphonates, therapeutic reagents against tumoral bone diseases (Paget's disease or osteoporosis), are potent inhibitors of bone resorption. The mechanisms by which they directly act on mature osteoclasts remain unclear. Using a recently developed technique for isolation of highly purified mammalian mature osteoclasts, we demonstrated that etidronate [ethane-1-hydroxy-1,1-diphosphonate (EHDP), 1-hydroxy-1,1-ethylidenebisphosphonate], inhibited directly osteoclastic bone-resorbing activity by pit assay. In addition, EHDP also directly induced apoptosis and disrupted actin rings in osteoclasts. The data support previous data on non-purified osteoclasts and results in vivo. Received: 26 June 1997 / Accepted: 27 July 1998     

TMC-171A,B,C and TMC-154, novel polyketide antibiotics produced by Gliocladium sp. TC 1304 and TC 1282

Four new antibiotics, TMC-171A (2), B (3), C (4) and TMC-154 (5) have been isolated from the fermentation of fungal strains Gliocladium sp. TC 1304 and TC 1282, respectively. Spectroscopic and degradation studies have shown that TMC-171s and TMC-154 were new members of the TMC-151 class of antibiotics, unique polyketides modified with a D-mannose and a D-mannitol or a D-arabitol. These compounds showed moderate cytotoxicity to various tumor cell lines.     

Clinical application of intrathecal lidocaine administration in surgery of the descending thoracic aorta

We studied the protective effects of intrathecally administered lidocaine against ischemic spinal cord injury during surgery. Seven patients (mean age 63.7 years, malefemale=61) with descending thoracic aortic aneurysms underwent reconstructive surgery. Following intrathecal lidocaine administration (10 ml), the operation was performed under femorofemoral bypass with an oxygenator. The aorta was cross-clamped at the distal end of the descending thoracic aorta and the proximal end of the lesions. The cross-clamping time was 47.1±23.3 minutes (mean ± SD). The operative procedure was total replacement of the descending thoracic aorta in five cases and patch closure in two. There were no operative deaths but paraparesis developed in two cases of total replacement. Neurological deficit was transient and disappeared in one case. In the other case, with 88 minutes of normothermic aortic cross-clamping, paraparesis gradually improved but was persistent after 7 months of follow-up. Graft anastomosis at the distal aortic arch was time consuming in this case and presumably caused prolonged spinal cord ischemia. Intrathecal administration of lidocaine was likely to reduce ischemic spinal cord injury and increase tolerance of the spinal cord to ischemia caused by prolonged aortic cross-clamping. This method was considered to provide a useful assistance to expand the safety limit of spinal cord ischemia in surgical reconstruction of the descending thoracic aorta requiring aortic occlusion. Tissue protective effects of intrathecal lidocaine administration may be further augmented by combining with deep hypothermia.     

Role of Ca2+-activated K+ channels in acetylcholine-induced dilatation of the basilar artery in vivo

1. We tested the hypothesis that activation of large conductance calcium-activated potassium channels is involved in dilator responses of the basilar artery to acetylcholine in vivo. Using a cranial window in anaesthetized rats, we examined responses of the basilar artery to acetylcholine.
2. Topical application of acetylcholine (10⁻⁶ and 10⁻⁵ M) increased diameter of the basilar artery from 238±7 μm to 268±7 and 288±7 μm, respectively (P<0.05 vs. baseline diameter). Iberiotoxin (10⁻⁸ M), an inhibitor of large conductance calcium-activated potassium channels, did not affect baseline diameter of the basilar artery. In the presence of 10⁻⁸ M iberiotoxin, 10⁻⁶ and 10⁻⁵ M acetylcholine increased diameter of the basilar artery from 239±7 μm to 246±7 and 261±7 μm, respectively. Thus, iberiotoxin attenuated acetylcholine-induced dilatation of the basilar artery (P<0.05).
3. Sodium nitroprusside (10⁻⁷ and 10⁻⁶ M) increased diameter of the basilar artery from 242±9 μm to 310±12 and 374±13 μm, respectively (P<0.05 vs. baseline diameter). In the presence of iberiotoxin (10⁻⁸ M), sodium nitroprusside (10⁻⁷ and 10⁻⁶ M) increased diameter of the basilar artery from 243±6 μm to 259±9 and 311±12 μm, respectively. Thus, iberiotoxin attenuated dilator responses of the basilar artery to sodium nitroprusside (P<0.05).
4. Iberiotoxin partly inhibited dilator responses of the basilar artery to forskolin, a direct activator of adenylate cyclase, but did not affect vasodilatation produced by levcromakalim, a potassium channel opener.
5. These results suggest that dilator responses of the basilar artery to acetylcholine and sodium nitroprusside are mediated, in part, by activation of large conductance calcium-activated potassium channels. Because both acetylcholine and sodium nitroprusside have been shown to activate guanylate cyclase via nitric oxide, activation of large conductance calcium-activated potassium channels may be one of the major mechanisms by which cyclic GMP causes dilatation of the basilar artery in vivo.