Rhenium 188-labeled anti-CD66 (a, b, c, e) monoclonal antibody to intensify the conditioning regimen prior to stem cell transplantation for patients with high-risk acute myeloid leukemia or myelodysplastic syndrome: results of a phase I-II study

The conditioning regimen prior to stem cell transplantation in 36 patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) was intensified by treating patients with a rhenium 188-labeled anti-CD66 monoclonal antibody. Dosimetry was performed prior to therapy, and a favorable dosimetry was observed in all cases. Radioimmunotherapy with the labeled antibody provided a mean of 15.3 Gy of additional radiation to the marrow; the kidney was the normal organ receiving the highest dose of supplemental radiation (mean 7.4 Gy). Radioimmunotherapy was followed by standard full-dose conditioning with total body irradiation (12 Gy) or busulfan and high-dose cyclophosphamide with or without thiotepa. Patients subsequently received a T-cell-depleted allogeneic graft from a HLA-identical family donor (n = 15) or an alternative donor (n = 17). In 4 patients without an allogeneic donor, an unmanipulated autologous graft was used. Infusion-related toxicity due to the labeled antibody was minimal, and no increase in treatment-related mortality due to the radioimmunoconjugate was observed. Day +30 and day +100 mortalities were 3% and 6%, respectively, and after a median follow-up of 18 months treatment-related mortality was 22%. Late renal toxicity was observed in 17% of patients. The relapse rate of 15 patients undergoing transplantation in first CR (complete remission) or second CR was 20%; 21 patients not in remission at the time of transplantation had a 30% relapse rate. (Blood. 2001;98:565-572)

Targeted bone marrow irradiation in the conditioning of high-risk leukaemia prior to stem cell transplantation

Disease recurrence following stem cell transplantation (SCT) remains a major problem. Despite the sensitivity of leukaemias to chemotherapy and irradiation, conventional conditioning before SCT is limited by significant organ toxicity. Targeted irradiation of bone marrow and spleen by radioimmunotherapy may provide considerable dose escalation, with limited toxicity to non-target organs. In this study, 27 patients with high-risk or relapsing leukaemia were treated with rhenium-188-labelled CD66a,b,c,e radioimmunoconjugates (188Re-mAb) specific for normal bone marrow in addition to conventional conditioning with high-dose chemotherapy and 12 Gy total body irradiation prior to SCT. A mean activity of 10.2+/-2.1 (range 6.9-15.8) GBq 188Re-mAb was administered intravenously. Acute side-effects were assessed according to the CTC classification and patient outcome was determined. Mean radiation doses (Gy; range in parentheses) to relevant organs and whole body were as follows: 13.1 (6.5-22) to bone marrow, 11.6 (1.7-31.1) to spleen, 5.0 (2.0-11.7) to liver, 7.0 (2.3-11.6) to kidneys, 0.7 (0.3-1.3) to lungs and 1.4 (0.8-2.1) to the whole body. Stem cells engrafted in all patients within 9-18 days post SCT. Acute organ toxicity of grade II or less was observed. During follow-up for 25.4+/-5.3 (range 18-34) months, 4/27 (15%) patients died from relapse, and 9/27 (33%) from transplantation-related complications. Fourteen patients (52%) are still alive and in ongoing complete clinical remission. Radioimmunotherapy with the bone marrow-seeking 188Re-labelled CD66 mAb can double the dose to bone marrow and spleen without undue extramedullary acute organ toxicity, when given in addition to high-dose chemotherapy and 12 Gy TBI before allogeneic SCT. This intensified conditioning regimen may reduce the relapse rate of high-risk leukaemia.

In vivo evaluation of 5-[(18)F]fluoro-2'-deoxyuridine as tracer for positron emission tomography in a murine pancreatic cancer model

We used a murine tumor progression model for the evaluation of potential proliferation markers using positron emission tomography (PET). 5-[(18)F]-2'-deoxyuridine ([(18)F]FdUrd) was synthesized with >98% radiochemical purity and investigated in a pancreatic cancer model, transforming growth factor alpha transgenic mice crossbred to p53 deficient mice. Thymidylate synthase was increased already in premalignant lesions, whereas thymidine kinase 1 mRNA levels were up-regulated 4-fold in the pancreatic cancer specimen of these mice. PET imaging was performed after injection of 1 MBq of [(18)F]FdUrd and 1 MBq of [(18)F]fluoro-deoxyglucose. Animals with pancreatic cancer displayed focal uptake of both tracers. The [(18)F]FdUrd uptake ratio closely correlated with the proliferation index as evaluated in morphometric and fluorescence-activated cell sorter analysis. These results indicate the potential of our tumor model for the evaluation of PET tracers and suggest [(18)F]FdUrd as a tracer for the assessment of proliferation in vivo.

Outcome of endoscopic sphincterotomy in patients with pain of suspected biliary or papillary origin and inconclusive cholangiography findings

BACKGROUND AND STUDY AIMS

We prospectively studied the outcome of endoscopic sphincterotomy in symptomatic patients with elevated liver enzyme levels but no clear evidence of biliary pathology on transabdominal ultrasound and diagnostic endoscopic retrograde cholangiography (ERC).

METHODS

29 consecutive patients with biliary-type pain (two or more out of eight criteria), elevated liver enzyme levels and no evidence of gallstones or significant common bile duct dilatation were evaluated. Elevated bilirubin levels (up to 7.2 mg/dl) were found in 18 patients. The majority of patients (n = 21) had a gallbladder in situ. The findings from bile duct exploration following sphincterotomy were recorded, and pain (as measured by visual analogue scale) as well as laboratory findings was assessed.

RESULTS

Wire-guided sphincterotomy was successful in all patients while uncomplicated pancreatitis occurred in one instance. In 16 patients (55%) there was macroscopic evidence of small stones (n = 2), sludge (n = 12) or both (n = 2) following bile duct exploration. In addition, microscopy showed bile crystals in all four patients who had no macroscopic findings. All four patients with elevation of pancreatic enzymes prior to treatment, and four of those eight patients with previous cholecystectomy, showed evidence of biliary pathology. The initial median pain intensity was 8 (range 1-10); 26 patients became pain-free within 3 months following endoscopic sphincterotomy. While 26 of 28 patients (93%) remained asymptomatic over a median follow-up period of 19 months (range 12-26), one died of an unrelated malignancy 6 months after therapy.

CONCLUSIONS

Endoscopic sphincterotomy may be acceptable in patients with typical clinical presentation suggesting a papillary or biliary origin of pain without further diagnostic work-up. Contrary to expectations, diagnostic ERC was insensitive in detection of the biliary etiology of symptoms in this selected group of patients.

Interventional endoscopic treatment of upper gastrointestinal bleeding - when, how, and how often

Acute upper gastrointestinal (GI) bleeding is still associated with high mortality. Reducing the rebleeding rate is the major challenge in therapeutic endoscopy. The following article describes the indications, techniques and limitations of endoscopic treatment of upper GI bleeding. Endoscopic techniques such as endoscopic sclerotherapy (EIS), endoscopic variceal ligation (EVL), cyanoacrylate obliteration, argon plasma coagulation (APC), and the application of hemoclip are described and compared concerning their efficacy. The pros and cons of "second-look" endoscopy are discussed.

Variceal bleeding and portal hypertension: still a therapeutic challenge?

In the primary prevention of variceal hemorrhage, beta-blockers continue to be the first-line treatment. Newer nonselective beta-blockers with anti-alpha1-adrenergic activity, such as carvedilol, appear to have a better impact on reducing the hepatic venous pressure gradient than propranolol. The addition of isosorbide mononitrate appears to improve the effectiveness of beta-blockers in primary prophylaxis, but not that of somatostatin in the treatment of acute variceal hemorrhage. The use of vasoactive drugs alone in acute variceal bleeding has not proved to be more effective than endoscopic treatment. The advent of endoscopic variceal ligation (EVL) has strengthened the role of endoscopy in the management of bleeding esophageal varices. EVL has improved the results, particularly in terms of lowering the treatment-related morbidity, compared with endoscopic variceal sclerotherapy (EVS). However, the variceal recurrence rate after initial eradication with EVL is relatively high. In contrast to synchronous combined therapy with EVL plus EVS, metachronous combination of EVL and low-dose EVS may improve the results of EVL alone. For bleeding fundic varices, obliteration using cyanoacrylate is currently the treatment of choice. Endosonography (EUS) is coming into more widespread use in the assessment of variceal eradication and in further attempts to improve the results of endoscopic injection therapy. According to two meta-analysis studies, transjugular intrahepatic portosystemic shunt (TIPS) is not yet capable of replacing endoscopic treatment in the secondary prevention of variceal bleeding.

In vivo endoscopic optical coherence tomography of the human gastrointestinal tract--toward optical biopsy

BACKGROUND AND STUDY AIMS

Optical coherence tomography (OCT) is a new technique for high-resolution cross-sectional imaging using infrared light. It has over 10 times the resolution of the currently available ultrasonography. Although in vitro studies have suggested its potential for gastrointestinal imaging, in vivo studies have not been possible so far on account of technical limitations.

PATIENTS AND METHODS

We describe here the first clinical study of OCT during routine endoscopy obtaining high resolution images of the normal esophageal, gastric, and colonic mucosa. Portable OCT equipment and a fiberoptic-based flexible probe for endoscopic use have been developed by the authors.

RESULTS

Differences in the optical properties of epithelium, lamina propria, muscularis mucosae, and submucosa enabled distinction of the mucosal architecture. Owing to the low penetration depth (1 mm) and high resolution (10 microm), OCT images may become comparable to mucosal histological findings. Image acquisition time was 1.5 seconds, and the entire procedure was completed within 5 minutes. Endoscopic OCT images of colonic adenoma and carcinoma were also studied and compared with the corresponding histology.

CONCLUSIONS

The newly developed portable OCT equipment and flexible fiberoptic probe makes OCT a promising method for endoscopic "optical biopsy".

Uncontrolled reoxygenation by initiating cardiopulmonary bypass is associated with higher protein S100 in cyanotic versus acyanotic patients

BACKGROUND

The systemic reoxygenation injury produced by initiating cardiopulmonary bypass (CPB) in infants with cyanotic heart disease may be associated with cerebral dysfunction and injury. Increased protein S100 (S100) serum levels may indicate cerebral and blood brain barrier damage as well as inflammatory changes, therefore serving to quantify these changes. The present clinical study assessed S100 in cyanotic patients undergoing CPB with normoxic versus hyperoxic paO2 in acyanotic cases and in controls without CPB.

METHODS

43 patients with congenital heart disease aged 5 days to 15 years (mean 4.4 years) were enrolled consecutively and divided in four groups: (1) Cyanotic infants undergoing controlled normoxic reoxygenation on CPB (n = 12), (2) cyanotic infants undergoing uncontrolled hyperoxic reoxygenation on CPB (n = 9), (3) acyanotic infants operated with CPB (n = 16) and (4) patients operated without CPB (n = 6). Blood samples were collected after induction of anesthesia (A), up to 4 hours after surgery (B) and at postoperative day one (C).

RESULTS

Preoperative S100 serum levels [microg/l] in all groups were below clinical relevance. S100 increased markedly after surgery in groups 1 and 2. Differences in postoperative S100 levels were significant between groups 1 (0.45 +/- 0.13) and 3 (0.35 +/- 0.09; p = 0.018), between groups 2 (1.41 +/- 0.47) and 3 (p = 0.01), and between groups 2 and 4 (0.29 +/- 0.09; p = 0.045). There were no significant differences in postoperative S100 levels (B) between groups 1 and 2 (p = 0.05), groups 1 and 4 (p = 0.05), or groups 3 and 4 (p = 0.93).

CONCLUSION

Uncontrolled hyperoxic reoxygenation on CPB for surgical correction of congenital heart defects is associated with higher S100 levels in cyanotic infants as compared to acyanotic patients undergoing comparable operations.

In vivo endoscopic optical coherence tomography of esophagitis, Barrett's esophagus, and adenocarcinoma of the esophagus

BACKGROUND AND STUDY AIMS

We studied the feasibility of endoscopic optical coherence tomography imaging in esophageal disorders, including Barrett's esophagus and Barrett-related adenocarcinoma. Optical coherence tomography is a high-resolution cross-sectional imaging technique with a resolution of almost 10 microm.

PATIENTS AND METHODS

The mucosal architecture of reflux esophagitis (n = 9) and Barrett's esophagus (n = 9) including Barrett-related esophageal cancer (n = 6) was studied by optical coherence tomography imaging.

RESULTS

In different stages of reflux esophagitis edema, fibrinoid deposits, or loss of the epithelial layer were observed. Optical coherence tomography images of Barrett's esophagus substantially differed from normal esophagus, reflux esophagitis, and esophageal carcinoma. A stratified structure of the mucosa was still preserved in Barrett's esophagus. However, images of Barrett-related cancer lacked the regular structure of the esophagus.

CONCLUSIONS

The high consistency of the first optical coherence tomography findings, the resolution of up to 10 microm, and the distinct pattern of normal, inflammatory, premalignant and malignant tissues make optical coherence tomography a promising method for endoscopically obtained optical biopsy.

[Endoscopic argon plasma coagulation of Barrett mucosa]

BACKGROUND

Up to 10% of patients with Barrett's esophagus develop adenocarcinoma of the distal esophagus. Endoscopic surveillance is recommended. We studied the potential of Argon plasma coagulation (APC) for eradication of Barrett's esophagus.

METHODS

Indication for APC was the histologic evidence of columnar epithelium with a length of > or = 2 cm, located proximal of the cardia and with the presence of goblet cells. Endoscopic therapy was performed using an Argonbeamer (Beamer 2, Erbe Company, Tübingen, Germany) under i.v. sedation and repeated in intervals of 2-3 weeks with the aim of complete eradication of Barrett's epithelium. One month after macroscopic Barrett eradication, superficial and deep biopsies were obtained every 2 cm in 4 quadrant technique to confirm the endoscopic aspect of complete eradication.

RESULTS

We report our results (follow-up median: 12 mths., 3-25) in the first 12 patients (8m/4f, median age 57 yrs., 42-69) in which treatment was completed. In one case there was evidence of moderate dysplasia. A mean of 5 (4-11) sessions were required for complete Barrett eradication in 11 patients (median size of Barrett-segment: 4 cm, range 2-11), in one patient partial regression of 50% was observed treatment was discontinued after 17 sessions while only. Deep biopsies showed subepithelial columnar epithelium islands in one case, recurrence of Barrett occurred in 2 cases after 3 and 6 months. Under APC-treatment, 11/12 patients complained about retrosternal pain and odynophagia. No other complications were observed.

CONCLUSION

Our preliminary results indicate that APC is safe and effective to eradicate Barrett's epithelium. Follow-up in a larger number of patients is necessary to assess longterm results (Barrett recurrence, decrease in the incidence of the adenocarcinoma), before APC may generally be recommended.

Radioimmunotherapy for the intensification of conditioning before stem cell transplantation: differences in dosimetry and biokinetics of 188Re- and 99mTc-labeled anti-NCA-95 MAbs

A new concept is the intensification of preparative regimens for patients with advanced leukemia using monoclonal antibodies (MAbs) with an affinity for beta emitter-labeled bone marrow. 188Re is a high-energy beta emitter that has therapeutic promise. Our first aim was to clarify whether the therapeutic application of 188Re-MAb against nonspecific cross-reacting antigen 95 (NCA-95) can be predicted from biokinetic data derived from 99mTc-labeled NCA-95. Our second aim was to show that a radiation absorbed dose of > or =12 Gy in the bone marrow can be achieved using 188Re-MAb.

METHODS

Dosimetric data were obtained for both radiotracers from multiple planar whole-body scans (double-head gamma camera), blood samples, and urine measurements from 12 patients with advanced leukemia. Radiation absorbed doses were calculated using MIRDOSE 3 software.

RESULTS

Radiation absorbed doses to bone marrow, liver, spleen, lung, and kidney were 2.24, 0.50, 1.93, 0.05, and 0.90 mGy/MBq, respectively, using 99mTc-MAb and 1.45, 0.43, 1.32, 0.07, and 0.71 mGy/MBq, respectively, using 188Re-MAb. These differences were statistically significant for bone marrow, spleen, and kidney. The main differences were less accumulation of 188Re-MAb in bone marrow (31%+/-13% compared with 52%+/-13%) and faster elimination through urine (25%+/-3% compared with 15%+/-5% after 24 h). On the basis of these data, a mean marrow dose of 14+/-7 Gy was achieved in 12 patients suffering from leukemia after application of approximately 10+/-2 GBq 188Re-MAb.

CONCLUSION

Myeloablative radiation absorbed doses can easily be achieved using 188Re-MAb. 99mTc- and 188Re-MAb showed similar whole-body distributions. However, direct prediction of radiation absorbed doses from the 99mTc-MAb, assuming identical biokinetic behavior, is not valid for the 188Re-MAb in a single patient. Therefore, individual dosimetry using 188Re-MAb is needed to calculate therapeutic activity.

Preparation and evaluation of the rhenium-188-labelled anti-NCA antigen monoclonal antibody BW 250/183 for radioimmunotherapy of leukaemia

Anti-NCA antigen antibody BW 250/183 (Anti-Granulocyte) localizes more than 50% of injected antibody dose to the bone marrow. Therefore, this antibody is promising for adjuvant conditioning radioimmunotherapy of bone marrow before bone marrow transplantation. To examine its potential use for radioimmunotherapy, we developed an efficient and reproducible technical protocol for labelling anti-NCA antigen antibody BW 250/183 with generator-produced rhenium-188, aiming at both high radiochemical yield and high specific activity. (188)Re-labelled BW 250/183 antibody was used in 12 patients with advanced leukaemia. Labelling of BW 250/183 with (188)Re was accomplished by the direct radiolabelling method using tris-(2-carboxyethyl) phosphine (TCEP) as the reducing agent. Twelve patients with recurrent acute or chronic leukaemia were treated with activities of 6.5-12.4 GBq of (188)Re-labelled BW 250/183. Standard gamma camera scintigraphy was used to evaluate the biodistribution, and a region of interest analysis together with the MIRDOSE 3.1 software was applied to determine the radiation doses to relevant tissues. The (188)Re-BW 250/183 antibody was labelled in high radiochemical yield, with high radiochemical purity (94%+/-3%) and specific activity (5.55-7.4 GBq/mg) within 1 h. The preliminary biodistribution studies showed persistent uptake of (188)Re-BW 250/183 in bone marrow. The radiation absorbed doses (mGy/MBq) delivered to the total body, red marrow, liver, spleen and kidneys were 0.13+/-0.02, 1.45+/-0.71, 0.43+/-0.21, 1.32+/-0.99 and 0.71+/-0. 17, respectively. TCEP reduction enabled the direct, fast and effective labelling of the monoclonal antibody BW 250/183 with (188)Re. Preliminary clinical results suggest delivery of a significant radiation dose to bone marrow and thus the potential for adjuvant conditioning therapy before BMT.

Stent retriever for dilation of pancreatic and bile duct strictures. brand@uke.uni-hamburg.de

BACKGROUND AND STUDY AIMS

Dilation of high grade strictures of pancreatic or biliary ducts using dilating or balloon catheters may fail. We evaluated the efficacy of the 7-Fr Soehendra Stent Retriever used as a dilator.

PATIENTS AND METHODS

Following sphincterotomy, the stricture was first negotiated with a 260 cm long 0.032-inch J-type Terumo wire. Dilation was then attempted using a 7-Fr dilating catheter. If the stricture could not be traversed, the 7-Fr Stent Retriever was inserted over the Terumo wire to dilate the stricture. Between May 1996 and January 1997, the Stent Retriever was used for dilation in 32 patients with biliary or pancreatic duct strictures.

RESULTS

The indication for therapeutic endoscopic retrograde cholangiopancreatography (ERCP) was symptomatic chronic pancreatitis in 21 patients (twelve men, nine women; mean age 45.7, range 26-70). The mean length (+/-SD) of the pancreatic duct strictures was 20mm+/-10 (range 3-55) with a prestenotic ductal diameter of 9mm+/-2 (range 2-15). Out of 21 patients, nine suffered from pancreaticolithiasis and were treated with extracorporeal shock wave lithotripsy. All but three patients underwent successful stenting in the same session. Another 11 patients (four men, seven women; mean age 67.4, range 47-85) had cholestasis because of benign or malignant bile duct strictures. The mean length of the strictures was 20mm+/-5 (range 3-40), and the mean prestenotic diameter was 10mm+/-5 (range 4-21). Stenting was easily done in all of these patients in the same session. Symptom relief was observed within the first week after stenting in all patients with a biliary or pancreatic stricture. In seven cases, material for cytological examination was obtained from the bile duct, which revealed malignancy in two cases. There was no complication associated with the use of the Stent Retriever. One subcapsular liver perforation was caused by the guide wire and occurred prior to the use of the Retriever.

CONCLUSIONS

Tight pancreatic and bile duct strictures can be dilated successfully with the Stent Retriever. The procedure is of low risk. In addition, tissue sampling is possible in some cases.

Advances in therapeutic endoscopic treatment of common bile duct stones

Advances in cannulation techniques and instruments have helped in difficult bile duct cannulation and thus stone extraction. For small common bile duct (CBD) stones, endoscopic papillary balloon dilatation has been proposed as an alternative to endoscopic papillotomy (EPT). The technique must undergo further evaluation before recommending its routine use. For most patients with bile duct stones, EPT remains the method of choice. Out of 8204 patients treated in three surgical endoscopy centers (Chile, Germany, and India), 86% to 91% of all CBD stones could be extracted subsequently after EPT using a Dormia basket; 4% to 7% required mechanical lithotripsy (ML) before removal and 3% to 10% of the patients needed other sophisticated techniques, such as electrohydraulic lithotripsy (EHL), laser-induced shock-wave lithotripsy (LISL), or extracorporeal shock-wave lithotripsy (ESWL). The local expertise and availability of equipment determines the choice of method used. In general, EHL or LISL is used for impacted CBD stones including stones in Mirizzi syndrome refractory to ML. ESWL is best suited for intrahepatic stones. Permanent stenting can be offered to poor risk patients instead of extensive procedures to clear the bile duct. Using currently available nonsurgical techniques, fewer than 1% of all patients with bile duct stones still require surgical intervention.

Effects of mesaconitine on [3H]noradrenaline uptake and neuronal excitability in rat hippocampus

Mesaconitine, one of the main alkaloids contained in Aconiti tubers, is a centrally acting analgesic without affinity to opioid receptors. It has been reported that the antinociception is due to an interaction with the noradrenergic system. In the present study, the effect of mesaconitine on the uptake of noradrenaline and on neuronal activity was examined in rat hippocampus. Experiments were performed as a study of [3H]noradrenaline uptake into rat hippocampal synaptosomes. Mesoconitine inhibited [3H]noradrenaline uptake in a concentration-dependent manner with a Ki of 111.95+/-18 nM. In a further series of experiments, the effects of mesaconitine on the extracellularly recorded population spike were investigated in rat hippocampal slices. At a concentration of 10 nM, mesaconitine increased the amplitude of the postsynaptic population spike by 31.10%+/-6.7% of control and elicited one or two additional spikes. The presynaptic fiber spike and the field excitatory postsynaptic potential were not affected by this alkaloid. The enhancement of neuronal activity was abolished by 1 microM propranolol as well as by 1 microM timolol. It is concluded that mesoconitine increased the excitability in rat hippocampal pyramidal cells by an involvement of the noradrenergic system, with at least one mechanism being inhibition of noradrenaline uptake leading to an enhanced extraneuronal noradrenaline level.

Improved endoscopic stenting for malignant dysphagia using Tygon plastic prostheses

BACKGROUND AND STUDY AIMS

Endoscopic palliative treatment of malignant esophageal stenosis using conventional plastic stents has been reported to be associated with a considerable risk of perforation. Stenoses with a distance of less than 2cm from the upper esophageal sphincter (UES) have generally been excluded from treatment. Using self-expandable metal stents, procedure-related complications are rare. However, the rates of late complications necessitating retreatment appear to be as high as those of plastic stents. This study describes our stent placement technique and our results using a modified Tygon plastic stent.

PATIENTS AND METHODS

Over a two-year period, 71 consecutive patients with incurable malignant esophageal stenosis were prospectively studied. Tygon plastic stents of diameter 9-14 mm were individually tailored according to length and location of the stenosis. Prior to stenting, stepwise bougienage was performed, if necessary over several sessions. After endoscopic placement of a guide wire, the stent was inserted over a bougie without fluoroscopic monitoring.

RESULTS

A total of 71 patients (54 men and 17 women, median age 69, range 34-93), were treated with Tygon plastic stents (14 mm: 19 patients; 12 mm: 50 patients; 9 mm: 2 patients). Median length of the strictures and of the stents were 7 (range 2-18) and 10 (range 6-25) cm, respectively. Four patients had an associated esophago-respiratory fistula. After a median of 2 (range 1-5) bougienage sessions, stent insertion was technically successful in all patients. Forty-one stents were placed across the cardia, 13 were positioned 0.5-1 cm below the UES. Three patients had to undergo retreatment within 24 hours because of pain or stent migration and the stents were repositioned or exchanged. No procedure-related perforation, hemorrhage or respiratory problems were observed. During a median follow-up of 63 (range 2-388) days, 82% of the patients died. Improvement or stabilization of dysphagia allowing for oral nutrition could be achieved in 89%. Dislocation occurred in eight patients, bolus obstruction in five patients and tumor overgrowth in four patients. Three of the four fistulas could be covered by the stent. In one patient with a fistula located at the level of the UES, a stent was placed but migrated after 5 days. Overall, 27 patients (38%) required reinterventions, mainly for dysphagia or nutritional problems.

CONCLUSIONS

In our experience, Tygon plastic stents with a diameter of 9-14 mm can be safely placed after stepwise, less extensive bougienage. Effective palliation is possible even for lesions located close to the UES. Perforation can be avoided. Reintervention rates seem to be comparable to those seen with self-expanding metal stents.

Endoscopic management of huge bezoars

BACKGROUND AND STUDY AIMS

After the first gastroscopic removal of a bezoar by McKechne in 1972, different endoscopic methods have been reported including a water jet, forceps, snare, and basket. Huge and solid bezoars, however, are still a problem. We report on our experience in fragmenting huge, solid bezoars using a modified needle-knife (bezotome) and a modified mechanical lithotriptor (bezotriptor).

PATIENTS AND METHODS

Over a period of 14 months (October 1994 to December 1995), a total of 15 patients (ten male, five female, median age 41 years) with 17 gastric bezoars and one esophageal bezoar, treated endoscopically, were included in the study. A monopolar diathermy knife with a 15 mm needle (bezotome) was used for trichobezoars. For diospyrobezoars we need a bezotriptor.

RESULTS

All 18 bezoars, from 4 x 3 x 3 cm to 10 x 8 x 8 cm in size, were successfully fragmented, ten in one session and eight in two sessions. Complete clearance of the upper digestive tract was achieved at the latest three days after the treatment. There were no complications.

CONCLUSIONS

Bezotome and bezotriptor are useful endoscopic devices to disintegrate huge, hard bezoars and achieve complete clearance.

Different effects on [3H]noradrenaline uptake of the Aconitum alkaloids aconitine, 3-acetylaconitine, lappaconitine, and N-desacetyllappaconitine in rat hippocampus

The effect of the Aconitum alkaloids aconitine, 3-acetylaconitine, lappaconitine, and N-desacetyllappaconitine to inhibit [3H]noradrenaline uptake was investigated in rat hippocampal synaptosomes. Aconitine and 3-acetylaconitine, which are known to activate sodium channels, had comparable inhibitory potencies and yielded Ki (inhibitor constant) values of 230 +/- 66 nM and 316 +/- 96 nM, respectively. In contrast, lappaconitine and N-desacetyllappaconitine failed to inhibit [3H]noradrenaline uptake. When either lappaconitine or N-desacetyllappaconitine was applied in combination with aconitine, [3H]noradrenaline uptake was not affected. The sodium channel blocker tetrodotoxin enhanced [3H]noradrenaline uptake, whereas uptake was completely blocked in sodium-free incubation medium. The inhibitory action of aconitine and 3-acetylaconitine on [3H]noradrenaline uptake was blocked by addition of tetrodotoxin. Patch clamp studies performed on cultured rat hippocampal neurons revealed an inhibitory action of lappaconitine and N-desacetyllappaconitine on whole cell sodium currents. It is concluded that the blockade of [3H]noradrenaline uptake evoked by aconitine and 3-acetylaconitine is mediated indirectly by an increased sodium concentration in the synaptosomes.

[3H]-monoamine uptake inhibition properties of kava pyrones

Three kava pyrones, the natural compounds (+)-methysticine and (+)-kavain, and the synthetic racemate (+/-)-kavain, were tested concerning their action on in vitro uptake of monoamines in synaptosomes prepared from the cerebral cortex and hippocampus of rats. (+/-)-Kavain and (+)-kavain were found to potently inhibit the uptake of [3H]-noradrenaline. Uptake of [3H]-noradrenaline was inhibited in the following order of potency: (+/-)-kavain = (+)-kavain > (+)-methysticine, whereas none of the kava pyrones efficiently blocked the uptake of [3H]-serotonin. The results indicate a pyrone-specific non-stereo-selective inhibition of the [3H]-noradrenaline uptake which might be responsible for or, at least, contribute to the psychotropic properties of kava pyrones.

Relaxation of evoked contractile activity of isolated guinea-pig ileum by (+/-)-kavain

Kava pyrones are the pharmacologically active compounds of Piper methysticum Forst. In the present study, the effect of the synthetic kava pyrone (+/-)-kavain was investigated on evoked contractile activity of isolated guinea-pig ileum. (+/-)-Kavain (1 microM-1 mM) dose-dependently reduced contractions of ileum evoked by carbachol (10 microM), by BAY K 8644 (0.3 microM), or by substance P (0.05 microM). (+/-)-Kavain also inhibited the contractile responses induced by raising the extracellular K+ concentration from 4 to 20 mM and by blocking the K+ channel by barium chloride (1 mM) or 4-aminopyridine (0.3 mM). After pre-incubation with 1 microM nifedipine, carbachol (1 microM) evoked 18.2 +/- 14.3% of contraction at control (i.e. prior pre-incubation with nifedipine). This remaining response was completely abolished by high concentrations of (+/-)-kavain (400 microM). After treatment of the longitudinal ileum strips with pertussis toxin (PTX), carbachol (1 microM) evoked 27.0 +/- 6.2% of the control response in untreated ileum. These contractions were also blocked by (+/-)-kavain (400 microM). However, (+/-)-kavain had no effect on the caffeine-induced (20 mM) contractions of ileum strips, which were permeabilized with digitonin or beta-escin. Moreover, it failed to affect Ca(2+)-evoked contractions of skinned muscles. These results suggest that the kava pyrone (+/-)-kavain may act in a non-specific musculotropic way on the smooth muscle membrane.