High-resolution endoscopy plus chromoendoscopy or narrow-band imaging in Barrett's esophagus: a prospective randomized crossover study

BACKGROUND AND STUDY AIMS

High-resolution endoscopy (HRE) may improve the detection of early neoplasia in Barrett's esophagus. Indigo carmine chromoendoscopy (ICC) and narrow-band imaging (NBI) may be useful techniques to complement HRE. The aim of this study was to compare HRE-ICC with HRE-NBI for the detection of high-grade dysplasia or early cancer (HGD/EC) in patients with Barrett's esophagus.

PATIENTS AND METHODS

Twenty-eight patients with Barrett's esophagus underwent HRE-ICC and HRE-NBI (separated by 6 - 8 weeks) in a randomized sequence. The two procedures were performed by two different endoscopists, who were blinded to the findings of the other examination. Targeted biopsies were taken from all detected lesions, followed by four-quadrant biopsies at 2-cm intervals. Biopsy evaluation was supervised by a single expert pathologist, who was blinded to the imaging technique used.

RESULTS

Fourteen patients were diagnosed with HGD/EC. The sensitivity for HGD/EC was 93 % and 86 % for HRE-ICC and HRE-NBI, respectively. Targeted biopsies had a sensitivity of 79 % with HRE alone. HGD was diagnosed from random biopsies alone in only one patient. ICC and NBI detected a limited number of additional lesions occult to HRE, but these lesions did not alter the sensitivity for identifying patients with HGD/EC.

CONCLUSIONS

In most patients with high-grade dysplasia or early cancer in Barrett's esophagus, subtle lesions can be identified with high-resolution endoscopy. Indigo carmine chromoendoscopy and narrow-band imaging are comparable as adjuncts to high-resolution endoscopy.

Significance of size and nucleic acid content heterogeneity as measured by flow cytometry in natural planktonic bacteria

Total bacterial abundances estimated with different epifluorescence microscopy methods (4',6-diamidino-2-phenylindole [DAPI], SYBR Green, and Live/Dead) and with flow cytometry (Syto13) showed good correspondence throughout two microcosm experiments with coastal Mediterranean water. In the Syto13-stained samples we could differentiate bacteria with apparent high DNA (HDNA) content and bacteria with apparent low DNA (LDNA) content. HDNA bacteria, "live" bacteria (determined as such with the Molecular Probes Live/Dead BacLight bacterial viability kit), and nucleoid-containing bacteria (NuCC) comprised similar fractions of the total bacterial community. Similarly, LDNA bacteria and "dead" bacteria (determined with the kit) comprised a similar fraction of the total bacterial community in one of the experiments. The rates of change of each type of bacteria during the microcosm experiments were also positively correlated between methods. In various experiments where predator pressure on bacteria had been reduced, we detected growth of the HDNA bacteria without concomitant growth of the LDNA bacteria, such that the percentage contribution of HDNA bacteria to total bacterial numbers (%HDNA) increased. This indicates that the HDNA bacteria are the dynamic members of the bacterial assemblage. Given how quickly and easily the numbers of HDNA and LDNA bacteria can be obtained, and given the similarity to the numbers of "live" cells and NuCC, the %HDNA is suggested as a reference value for the percentage of actively growing bacteria in marine planktonic environments.

Continuous synthesis of amorphous carbonated apatites

Amorphous carbonated hydroxyapatite was prepared by rapid mixing of aqueous solutions of a continuous computer-controlled reactor. The variation of the carbonate content in the solid product is possible by adjustment of the ratios of phosphate to carbonate in the initial solution. The principal reaction parameters (temperature, pH, stirrer speed, solution composition and supersaturation) are controlled and monitored. By controlling these processing parameters, a non-stoichiometric hydroxyapatite with fine-tuned crystallinity, morphology, and carbonate content can be reproducibly prepared. The higher solubility under the conditions of osteoclastic resorption was tested in vitro at constant pH (4.4).

Endoscopic video autofluorescence imaging may improve the detection of early neoplasia in patients with Barrett's esophagus

BACKGROUND

The aim of this study was to investigate the feasibility of detecting high-grade dysplasia (HGD) and early cancer (EC) in Barrett's esophagus (BE) with a prototype video autofluorescence endoscope.

METHODS

Sixty patients with BE were evaluated with a prototype, high-resolution videoendoscope that has separate charge-coupled devices for white light endoscopy (WLE) and autofluorescence imaging (AFI). Nondysplastic BE appears green on AFI, whereas potentially neoplastic areas appear blue/violet. The BE was first screened with WLE for visible abnormalities and then was examined by AFI to detect additional lesions. Lesions that raised a suspicion of neoplasia and control areas that were normal on AFI were sampled for histopathologic assessment. Finally, random 4-quadrant biopsy specimens were obtained at 2-cm intervals.

RESULTS

A diagnosis of HGD/EC was made in 22 patients; one patient had no visible abnormality, and 21 had endoscopically detectable areas with HGD/EC. In 6 of the latter 21 patients, the HGD/EC was detected with AFI alone; in another patient, HGD/EC was detected with AFI and random biopsies. In 14 patients, HGD/EC was detected with both WLE and AFI; in 3 of these 14 patients, additional lesions containing HGD/EC were detected by AFI alone.

CONCLUSIONS

The results of this study suggest that video AFI may improve the detection of HGD/EC in patients with BE.

Endoscopic video-autofluorescence imaging followed by narrow band imaging for detecting early neoplasia in Barrett's esophagus

BACKGROUND

Video-autofluorescence imaging (AFI) and narrow band imaging (NBI) are new endoscopic techniques that may improve the detection of high-grade intraepithelial neoplasia (HGIN) in Barrett's esophagus (BE). AFI improves the detection of lesions but may give false-positive findings. NBI allows for detailed inspection of the mucosal and (micro)vascular patterns, which are related to HGIN.

OBJECTIVE

A proof-of-principle study to combine AFI and NBI to improve the detection of HGIN and to reduce false-positive findings.

DESIGN

Cross-sectional study of consecutive eligible patients.

SETTING

Single-center.

PATIENTS

Twenty patients with BE with suspected or endoscopically treated HGIN were investigated with 2 prototype imaging systems: AFI (inspection with high-resolution videoendoscopy and autofluorescence imaging for detection of lesions) and NBI (for detailed inspection of mucosal and vascular patterns of identified lesions). Lesions were sampled for histopathologic evaluation.

MAIN OUTCOME MEASUREMENTS

The positive predictive value of AFI alone and of AFI-NBI for detecting HGIN and the reduction of false-positive findings because of the use of NBI.

RESULTS

All of the 28 lesions with HGIN were identified with AFI. Seventeen were identified with white light (61%). Forty-seven suspicious lesions were detected with AFI: 28 contained HGIN (60%) and 19 were false positive (40%). With NBI, 25 of the true-positive lesions had definitely suspicious patterns, and 3 had dubiously suspicious patterns. Of the 19 false positives, 14 were not suspicious on NBI. The false-positive rate, therefore, was reduced from 40% to 10%. Low-grade dysplasia was found in 4 of the remaining 5 false positives. All of the 14 patients with HGIN were identified by AFI-NBI (sensitivity 100%).

LIMITATIONS

Uncontrolled study in high-risk patients.

CONCLUSIONS

This proof-of-principle study confirms that AFI can be used as a red-flag technique to detect suspicious lesions. With NBI, detailed inspection of the surface patterns can be performed. This combination may increase the accuracy of detecting HGIN in BE.

Fatal pulmonary embolism in hospitalised patients: a necropsy review

AIMS

To carry out a retrospective review of all postmortem reports during the period 1991 to 2000 at King's College Hospital, London, as an extension of a previous analysis performed for the period 1965 to 1990.

METHODS

The number of deaths resulting from necropsy confirmed fatal pulmonary embolism in hospitalised patients was determined, and a limited analysis of the clinical characteristics of those patients who died was performed.

RESULTS

During the 10 year period, 16 104 deaths occurred and 6833 (42.4%) necropsies were performed. The outcome measure, fatal pulmonary embolism, was recorded as cause of death in 265 cases (3.9% of all necropsies; 5.2% of adult cases). No deaths from pulmonary embolism occurred in patients under 18 years of age; 80.0% occurred in patients older than 60 years. Of the fatal emboli, 214 of 265 (80.8%) occurred in patients who had not undergone recent surgery. Of these patients, 110 (51.4%) had suffered an acute medical illness in the six weeks before death, most often an acute infectious episode (26 cases).

CONCLUSIONS

Thromboembolic events remain a relatively common cause of death in hospitalised patients and appear to occur more frequently in non-surgical than in surgical patients.

Endoscopic treatment of high-grade dysplasia and early stage cancer in Barrett's esophagus

BACKGROUND

The aim of this study was to prospectively evaluate endoscopic resection (ER) combined with photodynamic therapy (PDT) for the treatment of selected patients with early neoplasia in Barrett's esophagus.

METHODS

Patients with Barrett's esophagus and neoplastic lesions <2 cm in diameter and no sign of submucosal infiltration, positive lymph nodes, or distant metastasis underwent diagnostic ER (cap technique). Patients with a T1sm tumor in the resection specimen were referred for surgery; those with a T1m or a less invasive tumor underwent additional endoscopic therapy (ER, PDT, and/or argon plasma coagulation [APC]), or they were followed. PDT was performed with 5-aminolevulinic acid and a light dose of 100 J/cm 2 at lambda = 632 nm.

RESULTS

Thirty-three patients underwent diagnostic ER. Endoscopic treatment was not performed in 5 patients, who underwent surgery (4 T1sm; 1, patient preference). Five patients were immediately entered into a follow-up protocol, and 23 received additional endoscopic treatment (13 additional ER, 19 PDT, 3 APC). Endoscopic treatment was successful in 26/28 patients; no severe complication was observed. During follow-up (median 19 months, range 13-24 months), 5/26 patients had a recurrence of high-grade dysplasia: all were successfully re-treated with ER. At the end of follow-up, 26/33 originally enrolled patients (79%) and 26/28 endoscopically treated patients (93%) were in local remission.

CONCLUSIONS

Endoscopic therapy is safe and effective for selected patients with early stage neoplasia in Barrett's esophagus.

Stepwise radical endoscopic resection is effective for complete removal of Barrett's esophagus with early neoplasia: a prospective study

OBJECTIVES

Endoscopic therapy for early neoplasia in Barrett's esophagus (BE) is evolving rapidly. Aim of this study was to prospectively evaluate safety and efficacy of stepwise radical endoscopic resection (ER) of BE containing early neoplasia.

METHODS

Patients with early neoplasia (i.e., high-grade intraepithelial neoplasia or early cancer) in BE < or = 5 cm, without signs of submucosal infiltration or lymph node/distant metastases, were included. Patients underwent resection sessions (cap technique after submucosal lifting) with intervals of 6 wk.

RESULTS

Between January 2003 and December 2004, 39 consecutive patients were included. Therapy was discontinued in two patients due to unrelated comorbidity. Complete eradication of early neoplasia was achieved in all 37 treated patients in a median number of three sessions. Complete removal of all Barrett's mucosa was achieved in 33 (89%) patients: 4 patients (all had undergone APC [argon plasma coagulation]) were found to have small isles of Barrett's mucosa underneath neosquamous mucosa. Complications occurred in two out of 88 (2%) ER procedures: one asymptomatic perforation, one delayed bleeding. Symptomatic stenosis occurred in 10 of 39 (26%) patients and was effectively treated by endoscopic bougienage. During a median follow-up of 11 months, no patients died and none had recurrence of neoplasia or Barrett's mucosa.

CONCLUSIONS

Stepwise radical ER is effective for selected patients with early neoplasia in BE; provides optimal histopathological diagnosis; and may reduce recurrence rate, since all mucosa at risk is effectively removed. Use of APC should be limited to prevent buried Barrett's mucosa. Methods for prevention of stenosis should be developed.

Randomized trial on endoscopic resection-cap versus multiband mucosectomy for piecemeal endoscopic resection of early Barrett's neoplasia

BACKGROUND

Endoscopic resection (ER) is an important treatment for high-grade intraepithelial neoplasia and early cancer in Barrett's esophagus. ER-cap requires submucosal lifting and positioning of a snare in the cap, making it technically demanding and laborious. Multiband mucosectomy (MBM) uses a modified variceal band ligator and requires no submucosal lifting or positioning of a snare.

OBJECTIVE

To compare ER-cap and MBM for piecemeal ER of early Barrett's neoplasia.

DESIGN

Randomized, controlled trial.

SETTING

Tertiary-care and community-care centers.

PATIENTS

This study involved 84 patients (64 men; median age 70 years) undergoing piecemeal ER of Barrett's neoplasia.

INTERVENTION

Piecemeal ER was performed by using ER-cap (n = 42) or MBM (n = 42).

MAIN OUTCOME MEASUREMENTS

Safety, efficacy, procedure time, costs.

RESULTS

Procedure time (34 vs 50 minutes; P = .02) and costs (€240 vs €322; P < .01) were significantly less with MBM compared with ER-cap. MBM resulted in smaller resection specimens than ER-cap (18 ×13 mm vs 20 × 15 mm; P < .01). Maximum thicknesses of specimens and resected submucosa were not significantly different. There were no clinically relevant bleeding episodes. Four perforations occurred, 3 with ER-cap, 1 with MBM (P = not significant).

LIMITATIONS

Potential bias because of different levels of experience among participating endoscopists.

CONCLUSION

Piecemeal ER with MBM is faster and cheaper than with ER-cap. Despite the lack of submucosal lifting, MBM appears not to be associated with more perforations. Although MBM results in slightly smaller specimens, the clinical relevance of this may be limited because depth of resections does not differ between both techniques. MBM may thus be preferred for piecemeal ER of early Barrett's neoplasia. (

CLINICAL TRIAL REGISTRATION NUMBER

NTR1435.).

Ternary complex formation between elongation factor Tu, GTP and aminoacyl-tRNA: an equilibrium study

The equilibria between the elongation factor Tu-GTP complex (EF-Tu-GTP) from Escherichia coli and tyrosyl-tRNATyr from E. coli as well as phenylalanyl-tRNAPhe and seryl-tRNASer from yeast were studied using a novel procedure, which takes advantage of the protective effect of ternary complex formation on the stability of theaminoacyl bond against non-enzymatic hydrolysis. At 25 degrees C and at pH 7.4 tyrosyl-tRNATyr, phenylalanyl-tRNAPhe and seryl-tRNASer are bound with binding constants of 0.7 X 10(7) M-1, 5.0 X 10(7) M-1 and 0.5 X 10(7) M-1 respectively. The binding of aminoacyl-tRNA to EF-Tu-GTP has a negative deltaH of the order of 10 kcal/mol (42 kJ/mol). Complex formation is dependent on ionic strength: with 0.1 M KCl Kass = 0.8 X 10(7) M-1, with 0.5 M KCl Kass = 0.2 X 10(7) M-1 was determined for the binding of Tyr-tRNATyr.

A site-directed mutagenesis study to identify amino acid residues involved in the catalytic function of the restriction endonuclease EcoRV

We have used site-directed mutagenesis of the EcoRV restriction endonuclease to change amino acid side chains that have been shown crystallographically to be in close proximity to the scissile phosphodiester bond of the DNA substrate. DNA cleavage assays of the resulting mutant proteins indicate that the largest effects on nucleolytic activity result from substitution of Asp74, Asp90, and Lys92. We suggest on the basis of structural information, mutagenesis data, and analogies with other nucleases that Asp74 and Asp90 might be involved in Mg2+ binding and/or catalysis and that Lys92 probably stabilizes the pentacovalent phosphorus in the transition state. These amino acids are part of a sequence motif, Pro-Asp...Asp/Glu-X-Lys, which is also present in EcoRI. In both enzymes, it is located in a structurally similar context near the scissile phosphodiester bond. A preliminary mutational analysis with EcoRI indicates that this sequence motif is of similar functional importance for EcoRI and EcoRV. On the basis of these results, a proposal is made for the mechanism of DNA cleavage by EcoRV and EcoRI.

Effective treatment of early Barrett's neoplasia with stepwise circumferential and focal ablation using the HALO system

STUDY AIMS

The aim of the current study was to evaluate the efficacy and safety of stepwise circumferential and focal ablation using the HALO system for Barrett's esophagus containing flat, high-grade dysplasia (HGD) or residual dysplasia after endoscopic resection for HGD or intramucosal cancer (IMC).

METHODS

Visible abnormalities were removed with endoscopic resection prior to ablation. Persistence of dysplasia and absence of IMC were confirmed with biopsy after endoscopic resection. A balloon-based electrode was used for primary circumferential ablation and an endoscope-mounted electrode was used for secondary focal ablation.

RESULTS

Twelve patients (nine men; median age 70 years) were treated (median Barrett's length 7 cm). Visible abnormalities were removed by endoscopic resection in seven patients. The worst pathological grade of residual Barrett's esophagus after resection and prior to ablation was low-grade dysplasia (LGD) (n = 1) and HGD (n = 11). Patients underwent a median of one circumferential and two focal ablation sessions. Complete remission of dysplasia was achieved in 12/12 patients (100%). Complete endoscopic and histological removal of Barrett's esophagus was achieved in 12/12 patients (100%). There were no ablation-related stenoses, and no subsquamous Barrett's esophagus was observed in 363 biopsies obtained from post-ablation neo-squamous mucosa. Protocolized cleaning of the ablation zone and electrode in between ablations resulted in superior regression of Barrett's esophagus compared with previous studies. During a median follow-up of 14 months no recurrence of dysplasia or Barrett's esophagus was observed.

CONCLUSIONS

Stepwise circumferential and focal ablation for Barrett's esophagus with flat HGD or for Barrett's with residual dysplasia after endoscopic resection for HGD/IMC is a safe and effective treatment modality. Its success rate and safety profile compare favorably with alternatives such as esophagectomy, widespread endoscopic resection or photodynamic therapy.

Stepwise circumferential and focal ablation of Barrett's esophagus with high-grade dysplasia: results of the first prospective series of 11 patients

BACKGROUND AND STUDY AIMS

Stepwise circumferential and focal ablation of nondysplastic Barrett's esophagus has proven safe and effective. This study assessed the efficacy and safety of ablation for Barrett's esophagus with high-grade dysplasia (HGD), and residual Barrett's esophagus with dysplasia after prior endoscopic resection for visible lesions.

PATIENTS AND METHODS

This was a prospective cohort study. All visible abnormalities were resected prior to ablation. Persistence of dysplasia and absence of invasive cancer was confirmed with biopsies after endoscopic resection. A balloon-based electrode was used for primary circumferential ablation and an endoscope-mounted electrode was used for secondary focal ablation. Eradication of dysplasia and Barrett's esophagus was the main outcome measure.

RESULTS

Eleven patients (eight men; median age 60 years) were treated (median Barrett's length 5 cm). Visible abnormalities were removed with endoscopic resection in six patients. The worst pathological grade of residual Barrett's esophagus after endoscopic resection and prior to ablation was LGD (n = 2) and HGD (n = 9). Patients underwent a median of two circumferential and two focal ablation sessions. Complete remission of dysplasia and complete endoscopic and histological removal of Barrett's esophagus was achieved in 11/11 patients (100%). There were no adverse events or strictures, and in none of the 473 biopsies of neo-squamous mucosa was subsquamous Barrett's esophagus ("buried Barrett's") observed. During a median follow-up period of 14 months after the last treatment session and a median number of two follow-up endoscopies, none of the patients showed recurrence of dysplasia or endoscopic signs of recurrent Barrett's mucosa.

CONCLUSIONS

Stepwise circumferential and focal ablation appears to be a safe and effective treatment for complete removal of Barrett's esophagus containing HGD, and can be safely performed after prior endoscopic resection for endoscopically visible abnormalities.

Biologically and chemically optimized composites of carbonated apatite and polyglycolide as bone substitution materials

We report on the development and characterization of a new composite material consisting of amorphous carbonated apatite, Ca(5)(PO(4), CO(3))(3)(OH), and microstructured poly(hydroxyacetic acid), polyglycolide (PGA). This material is able to keep the pH of a surrounding solution within the physiological range (7.2-7.6). This was achieved by chemical fine-tuning of the counterplay between the acidic degradation of the polyester and the basic dissolution of calcium phosphate. Microporous samples with pore sizes of <1 microm and compact samples were prepared. The biological behavior was assayed in vitro by long-term osteoblast culture. Morphological and biochemical analyses of cell differentiation revealed excellent biocompatibility, leading to cell attachment, collagen and osteocalcin expression, and mineral deposition. This material could be of use as a biodegradable bone substitution material and as a scaffold for tissue engineering.

Clinical electrophysiologic effects of encainide, a newly developed antiarrhythmic agent

Encainide is a newly developed antiarrhythmic agent. With the use of intracardiac electrophysiologic techniques, its effects on the cardiac conduction system were examined in 10 patients with coronary artery disease. Five patients received 0.6 and five received 0.9 mg/kg body weight of encainide intravenously over 15 minutes. Plasma concentration, heart rate, blood pressure and conduction intervals (A-H, H-V, QRS and Q-T) were measured before, during and after encainide infusion. In addition, sinus nodal recovery time, Wenckebach cycle length, and atrial, atrioventricular (A-V) nodal and right ventricular refractory periods were measured before and after encainide infusion. The average peak plasma concentration was 0.49 +/- 0.35 microgram/ml (mean +/- standard error of the mean). Encainide significantly prologned H-V and QRS intervals in all patients by an average of 31 +/- 7 and 18 +/- 9 percent (standard deviation) (P less than 0.001), respectively. A minimal increase in the Q-T interval was also observed after encainide infusion (2 +/- 9 percent, P less than 0.01), but no significant changes were noted in heart rate, blood pressure, A-H interval, corrected sinus noal recovery time, Wenckebach cycle length or refractory periods of the atrium, A-V node or right ventricle. It is concluded that encainide significantly prolongs conduction in the His-Purkinje system without affecting conduction or refractoriness of other parts of the cardiac conduction system in man.

Can we Save the rectum by watchful waiting or TransAnal microsurgery following (chemo) Radiotherapy versus Total mesorectal excision for early REctal Cancer (STAR-TREC study)?: protocol for a multicentre, randomised feasibility study

INTRODUCTION

Total mesorectal excision (TME) is the highly effective standard treatment for rectal cancer but is associated with significant morbidity and may be overtreatment for low-risk cancers. This study is designed to determine the feasibility of international recruitment in a study comparing organ-saving approaches versus standard TME surgery.

METHODS AND ANALYSIS

STAR-TREC trial is a multicentre international randomised, three-arm parallel, phase II feasibility study in patients with biopsy-proven adenocarcinoma of the rectum. The trial is coordinated from Birmingham, UK with national hubs in Radboudumc (the Netherlands) and Odense University Hospital Svendborg UMC (Denmark). Patients with rectal cancer, staged by CT and MRI as ≤cT3b (up to 5 mm of extramural spread) N0 M0 can be included. Patients will be randomised to either standard TME surgery (control), organ-saving treatment using long-course concurrent chemoradiation or organ-saving treatment using short-course radiotherapy. For patients treated with an organ-saving strategy, clinical response to (chemo)radiotherapy determines the next treatment step. An active surveillance regime will be performed in the case of a complete clinical regression. In the case of incomplete clinical regression, patients will proceed to local excision using an optimised platform such as transanal endoscopic microsurgery or other transanal techniques (eg, transanal endoscopic operation or transanal minimally invasive surgery). The primary endpoint of this phase II study is to demonstrate sufficient international recruitment in order to sustain a phase III study incorporating pelvic failure as the primary endpoint. Success in phase II is defined as randomisation of at least four cases per month internationally in year 1, rising to at least six cases per month internationally during year 2.

ETHICS AND DISSEMINATION

The medical ethical committees of all the participating countries have approved the study protocol. Results of the primary and secondary endpoints will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN14240288, 20 October 2016. NCT02945566; Pre-results, October 2016.

International consensus recommendations on key outcome measures for organ preservation after (chemo)radiotherapy in patients with rectal cancer

Multimodal treatment strategies for patients with rectal cancer are increasingly including the possibility of organ preservation, through nonoperative management or local excision. Organ preservation strategies can enable patients with a complete response or near-complete clinical responses after radiotherapy with or without concomitant chemotherapy to safely avoid the morbidities associated with radical surgery, and thus to maintain anorectal function and quality of life. However, standardization of the key outcome measures of organ preservation strategies is currently lacking; this includes a lack of consensus of the optimal definitions and selection of primary end points according to the trial phase and design; the optimal time points for response assessment; response-based decision-making; follow-up schedules; use of specific anorectal function tests; and quality of life and patient-reported outcomes. Thus, a consensus statement on outcome measures is necessary to ensure consistency and facilitate more accurate comparisons of data from ongoing and future trials. Here, we have convened an international group of experts with extensive experience in the management of patients with rectal cancer, including organ preservation approaches, and used a Delphi process to establish the first international consensus recommendations for key outcome measures of organ preservation, in an attempt to standardize the reporting of data from both trials and routine practice in this emerging area.

Electronic communication in oligometallic complexes with ferrocene-based tris(1-pyrazolyl)borate ligands

Ferrocene-based tris(1-pyrazolyl)borate ligands 1R-Li and 1R-Tl have been synthesized and used to generate a variety of heterotrinuclear transition metal complexes, 3R-M [R = H, SiMe(3), cyclohexyl, (cyclohexyl)methyl, phenyl; M(II) = Mn, Fe, Co, Ni, Cu, Zn]. The poor solubility of 3H-M is greatly enhanced by the introduction of large organic substituents into the 4-positions of all pyrazolyl rings. The unsubstituted ligand 1H-Li and the trinuclear complex 3Cym-Cu [Cym = (cyclohexyl)methyl] have been investigated by X-ray crystallography. 1H-Li, which represents the first example of a structurally characterized lithium tris(1-pyrazolyl)borate, forms centrosymmetric dimers in the solid state. A severe Jahn-Teller distortion was observed for the (Bpz(3))(2)Cu fragment in 3Cym-Cu. Compared to the parent compounds [(HBpz(3))(2)M], the presence of uncharged ferrocenyl substituents in 3R-M tends to shift the M(2+)/M(3+) redox potential to significantly more cathodic values. The opposite is true if the ferrocenyl fragments are in their cationic state, which results in an anodic shift of the M(2+)/M(3+) transition. Most interestingly, the two ferrocenyl fragments in 3R-Cu appear to be electronically communicating.

Distinct steps in the specific binding of tRNA to aminoacyl-tRNA synthetase. Temperature-jump studies on the serine-specific system from yeast and the tyrosine-specific system from Escherichia coli

The kinetics of the interaction of tRNASer and seryl-tRNA synthetase from yeast as well as of tRNATyr and tyrosyl-tRNA synthetase from Escherichia coli have been investigated by temperature-jump experiments. It could be shown that complex formation proceeds in two distinct steps. This was demonstrated for both the first and the second binding site. The two-step mechanism was deduced from the characteristic concentration dependence of the relaxation times. Seryl-tRNA synthetase recombines with the first tRNA to form an intermediate complex (kI12, kI21), which is transformed in a fast reaction to the final 1:1 complex (kI23, kI32). At pH 7.2 with 0.1 M KCl the rate constants are: kI12 = 2.7 X 10(8) M-1 S-1; kI23, kI32). At pH 7.2 with 0.1 M KCl the rate constants are: kI12 = 2.7 x 10(8) M-1 S-1; kI21 = 220 S-1; kI23 = 760 S-1; kI32 = 330 S-1. The 1:1 complex can bind a second tRNA. At pH 7.2 without added salt the rate constants are: KII2 = 0.9 X 10(8) M-1 S-1; kII21 = 270 S-1; kII23 = 120 S-1; kII32 = 1250 S-1. The tyrosine-specific system behaves very similarly to the serine-specific system. Data are given for pH 7.2 (pH 6.0) for the binding of the second tRNA: kII12 = 1 X 10(8) (2.5 X 10(8)) M-1 S-1; kII21 = 470 (170) S-1; kII23 = 150 (530) S-1; kII32 = 1540 (720) S-1. The kinetic results are discussed in terms of their relevance to the recognition process and their relation to the anticooperative binding behaviour of tRNA to synthetase.

Clinical pharmacology and antiarrhythmic efficacy of encainide in patients with chronic ventricular arrhythmias

We determined the pharmacokinetics, efficacy and therapeutic plasma concentration of encainide, a new antiarrhythmic drug that affects His-Purkinje conduction but not ventricular refractoriness. Nine patients with frequent and complex premature ventricular complexes were studied in a 3-day double-blind protocol. Each day, each patient received 75 mg of i.v. or oral encainide or placebo. Frequent blood samples for encainide plasma concentration determination and continuous ambulatory ECGs were obtained. There was a marked intersubject variation in bioavailability (mean 42 +/- 24%, range 7.4-82%), clearance (13.2 +/- 5.6 ml/min/kg, range 3.75-22.1 ml/min/kg) and half-life (3.4 +/- 1.7 hours i.v., 2.5 +/- 0.8 hours oral). Eight of nine patients had more than 90% suppression of premature ventricular complexes for 3-36 hours. Minimal antiarrhythmic plasma concentration was higher (39 +/- 54 ng/ml, range 3.5-170 ng/ml) after i.v. dosing than after oral dosing (14 +/- 16 ng/ml, range 1.5-48 ng/ml), suggesting an active metabolite after oral dosing in many patients. Minimal side effects were seen despite high peak plasma concentrations (range 794-1556 ng/ml i.v., 36-495 ng/ml oral). The minimal ratio of toxic to therapeutic plasma concentration ranged from 4.3-326 (median 23) after oral dosing. Antiarrhythmic action was associated with an 11-44% widening of the QRS complex that was not associated with other adverse effects. We conclude that encainide effectively suppresses ventricular arrhythmias. Despite a variable bioavailability, high clearance and short half-life, its wide ratio of toxic to therapeutic concentration and probable active metabolite permit a long duration of action, which should allow a reasonable dose schedule in most patients during chronic oral dosing.

Equivalent and non-equivalent binding sites for tRNA on aminoacyl-tRNA synthetases

Complexes between tRNAPhe (yeast), tRNASer (yeast) and tRNATyr (Escherichia coli) and their cognate aminoacyl-tRNA synthetases have been studied by sedimentation velocity runs in an analytical ultracentrifuge. The amount of complex formation was determined by the absorption and the sedimentation coefficients of the fast-moving boundary in the presence of excess tRNA or excess synthetase respectively. The same method has been applied to unspecific combinations of tRNAs and synthetases. Inactive material of tRNA or synthetase does not influence the results. 1. Two moles of tRNAPhe can be bound to one mole of phenylalanyl-tRNA synthetase with a binding constant greater than 10(6) M-1. The binding constants for both tRNAs are very similar; the binding sites are independent of each other. Omission of Mg2+ does not prevent binding. 2. Two moles of tRNASer can be bound to one mole of Seryl-tRNA synthetase; the binding of the first and second tRNA is non-equivalent, K1 greater than 10(6) M-1, K2 is determined to be 1.3 X 10(5) M-1 at pH 7.2. Omission of Mg2+ prevents complex formation. 3. Tyrosyl-tRNA synthetase behaves very similarly to seryl-tRNA synthetase. The binding constant for the weakly bound tRNA is 2.3 X 10(5) M-1 at pH 7.2, and 2.5 X 10(6) M-1 at pH 6.0. No complexes are observed in the absence of Mg2+. 4. Unspecific binding was only obtained with phenylalanyl-tRNA synthetase. It binds tRNASer (yeast), tRNAAla (yeast) and tRNATyr (E. coli) with a binding constant about 100 times lower compared to its cognate tRNA. The binding data are discussed with respect to the tertiary structure of the tRNAs, the subunit structure of the synthetases and the possible physical basis for the non-equivalence of binding sites.

Surveillance history of endoscopically treated patients with early Barrett's neoplasia: nonadherence to the Seattle biopsy protocol leads to sampling error

The study's aim was to retrospectively evaluate the surveillance history of Barrett's esophagus (BE) patients with endoscopically treated early neoplasia. All BE patients endoscopically treated for early cancer (EC) or high-grade intraepithelial neoplasia (HGIN) in a lesion or mass between 1998 and 2005 were included. Endoscopy and histology records were reviewed. Ninety-four patients (78 males, mean age 67 years, 24 HGIN, 70 EC) were included. In 36 (38%) patients, HGIN/EC was diagnosed at (or within 6 months after) initial endoscopy. The remaining 58 (62%) patients had a surveillance history (median duration 7 years, mean 6.7 endoscopies). Seventy-nine percent of these had low-grade intraepithelial neoplasia (LGIN) diagnosed at least once during their surveillance period with a median of seven endoscopies and a median number of biopsies that was 50% of what should have been taken according to the Seattle protocol. Patients without any dysplasia during earlier surveillance (n = 12, 21%) had undergone significantly less endoscopies (median four endoscopies, P = 0.02) and had a median biopsy percentage that was 23% of the Seattle protocol (P < 0.001 versus 50% in LGIN). In this selected cohort of patients with early Barrett's neoplasia, 38% of patients were diagnosed at initial endoscopy. Of the patients with a surveillance history, 79% had shown LGIN prior to HGIN/EC diagnosis. Only 21% of patients had a surveillance history without any dysplasia, which in general encompassed endoscopies with an insufficient number of biopsies, suggesting sampling error. This underlines the importance of obtaining an adequate number of biopsies during surveillance endoscopies.

Contribution of smoking to socioeconomic inequalities in mortality: a study of 14 European countries, 1990-2004

BACKGROUND

Smoking contributes to socioeconomic inequalities in mortality, but the extent to which this contribution has changed over time and driven widening or narrowing inequalities in total mortality remains unknown. We studied socioeconomic inequalities in smoking-attributable mortality and their contribution to inequalities in total mortality in 1990-1994 and 2000-2004 in 14 European countries.

METHODS

We collected, harmonised and standardised population-wide data on all-cause and lung-cancer mortality by age, gender, educational and occupational level in 14 European populations in 1990-1994 and 2000-2004. Smoking-attributable mortality was indirectly estimated using the Preston-Glei-Wilmoth method.

RESULTS

In 2000-2004, smoking-attributable mortality was higher in lower socioeconomic groups in all countries among men, and in all countries except Spain, Italy and Slovenia, among women, and the contribution of smoking to socioeconomic inequalities in mortality varied between 19% and 55% among men, and between -1% and 56% among women. Since 1990-1994, absolute inequalities in smoking-attributable mortality and the contribution of smoking to inequalities in total mortality have decreased in most countries among men, but increased among women.

CONCLUSIONS

In many European countries, smoking has become less important as a determinant of socioeconomic inequalities in mortality among men, but not among women. Inequalities in smoking remain one of the most important entry points for reducing inequalities in mortality.

Development of an enzyme-linked immunosorbent assay for specific equine neutrophil myeloperoxidase measurement in blood

Equine inflammatory disease is accompanied by a neutrophil activation resulting in the release of granulocytic enzyme myeloperoxidase (MPO). To measure MPO in horse plasma as marker of neutrophil activation, the authors purified equine neutrophil MPO and developed a specific enzyme immunoassay using 2 specific polyclonal antibodies obtained from rabbit (primary antibody) and guinea pig (secondary antibody). The sandwich complex "primary antibody-MPO-secondary antibody" was detected using a goat anti-guinea pig immunoglobulin antibody conjugated to alkaline phosphatase. The enzyme-linked immunosorbent assay (ELISA) showed good precision and accuracy, with intra- and interassay coefficients of variation below 10% for MPO concentrations ranging from 0.78 to 50 ng/ml. A stable plasma MPO value, unaffected by time elapsed between blood collection and centrifugation, was obtained with plasma from EDTA anticoagulated blood. The mean MPO value measured in 38 healthy horses was 181.80 +/- 64.74 ng/ml. In 20 horses suffering from obstruction of the large or small intestine, MPO concentrations measured at the time of arrival at the intensive care unit were significantly higher than mean normal value, ranging from 477.88 to 2,748.13 ng/ml. Work is in progress to apply this MPO ELISA technique to other biological fluids and other equine diseases.