At the 1990 World Congresses of Gastroenterology, the Working Party on Helicobacter pylori (H. py... more At the 1990 World Congresses of Gastroenterology, the Working Party on Helicobacter pylori (H. pylori) recommended that, in suitable patients, the bacterium should be eradicated using a therapeutic regimen comprising a bismuth salt, tetracycline and metronidazole for two weeks. We have treated 40 patients infected with H. pylori with‘triple’ therapy consisting of 120 mg tripotassium dicitrato bismuthate q.d.s., 500 mg tetracycline q.d.s. and 400 mg metronidazole t.d.s. for two weeks.The success rate, in terms of bacterial eradication, was 19/21 (90.5%) in patients with metronidazole-sensitive organisms, compared with only 6/19 (31.6%) in patients whose H. pylori were resistant to metronidazole (P < 0.01). Side effects, particularly diarrhoea and vomiting/nausea, were common: 23/40 patients reported such symptoms during the 14-day course of therapy. Fifteen of these 23 patients completed the entire 14-day course, although suffering from significant side effects, while the remaining eight patients had to discontinue the treatment because side effects became intolerable.If a form of triple therapy is going to be widely used to eradicate H. pylori infection, the regimen will have to be simpler, shorter, produce fewer side effects and be more effective in patients with metronidazole-resistant bacteria.
The vigorous debate over whom to sedate, when to sedate, and how to sedate shows no sign of runni... more The vigorous debate over whom to sedate, when to sedate, and how to sedate shows no sign of running out of steam. There is a general consensus that patients should be more involved in the decision-making process for the sedation &amp;amp;amp;amp;quot;menu&amp;amp;amp;amp;quot;. A move away from the take-it-or-leave-it attitude of all or nothing to an &amp;amp;amp;amp;quot;à la carte&amp;amp;amp;amp;quot; choice is to be encouraged. A new textbook and several further guidelines have appeared. The particular problems associated with sedating the elderly are briefly presented. The pros and cons of using local pharyngeal anaesthesia are discussed. Enthusiasm for the use of intravenous propofol is gathering momentum, despite continuing worries about its safety in the hands of the nonanaesthetist. For many endoscopists, the combination of a benzodiazepine plus (or minus) an opioid with which they are most familiar is still the best compromise in terms of efficacy, cost, and safety. Fatal drug-induced cardiopulmonary complications continue to occur, despite a general trend toward using smaller doses of sedation than we did 5 - 10 years ago. Monitoring techniques that are at present considered as research tools may one day become commonplace. These include: the use of an electroencephalography parameter known as bispectral analysis; transcutaneous CO(2) measurement; and a modified continuous capnographic waveform trace to monitor ventilatory effort. Bispectral analysis may be of use in monitoring central nervous system depression and helping to distinguish between conscious sedation and deep sedation. If the measurement of CO(2) levels, either transcutaneously or in breath samples, was as easy and inexpensive as measuring SpO(2) with a pulse oximeter, then undoubtedly such technology would enhance the early detection of sedative-induced hypoventilation and apnoea. Further evidence regarding droperidol&amp;amp;amp;amp;#39;s possible role in conscious sedation is presented. Pain during colonoscopy remains a problem, and the possible role for intraluminal injection of peppermint oil, as well as the value of variable-stiffness colonoscopes, in reducing the need for intravenous sedation is discussed. Case reports of hyponatraemic encephalopathy and hypocalcaemic tetany as complications of oral bowel preparation are presented, as is the challenge associated with adequate bowel preparation in diabetic patients.
IEEE Transactions on Instrumentation and Measurement, 2007
This paper proposes a novel method of using electromyographic (EMG) potentials generated by the f... more This paper proposes a novel method of using electromyographic (EMG) potentials generated by the forearm muscles during hand and finger movements to control an artificial prosthetic hand worn by an amputee. Surface EMG sensors were used to record a sequence of forearm EMG potential signals via a PC sound card and a novel 3-D electromagnetic positioning system together with a data-glove mounted with 11 miniature electromagnetic sensors used to acquire corresponding human hand pose in real time. The synchronized measurements of hand posture and associated EMG signals stored as prototypes embody a numerical expression of the current hand shape in the form of a series of data frames, each comprising a set of postures and associated EMG data. This allows a computer generated graphical 3-D model, combined with synthesized EMG signals, to be used to evaluate the approach. This graphical user interface could also enable handicapped users to practice controlling a robotic prosthetic hand using EMG signals derived from their forearm muscles. We believe this task might be made easier using a dictionary of stored task-specific prototype data frames acquired from able-bodied users. By comparing the resulting EMG data frames with stored prototypes, the most likely data frame sequence can be identified and used to control a robotic hand so that it carries out the user's desire. We explore the feasibility of this approach by applying frequency analysis on the signal derived from a multichannel EMG measurement device and identify pattern recognition techniques in the time and frequency domains to determine plausible hand shapes. This approach offers several advantages over existing methods. First, it simplifies the classification procedure, saving computational time and the requirement for the optimization process, and second, it increases the number of recognizable hand shapes, which in turn improves the dexterity of the prosthetic hand and the quality of life for amputees. The database of EMG prototypes could be employed to optimize the accuracy of the system within a machine learning paradigm. By making a range of EMG prototype databases available, prosthetic hand users could train themselves to use their prosthesis using the visual reference afforded by the virtual hand model to provide feedback.
After cardiopulmonary complications, perforation is the second most important cause of complicati... more After cardiopulmonary complications, perforation is the second most important cause of complications following flexible upper gastrointestinal endoscopy. A recent audit of 14149 procedures detected a perforation rate of 0.05 per cent (overall mortality rate 0.008 per cent) during diagnostic endoscopy, and a perforation rate of 2.6 percent (overall mortality rate 1.0 per cent) following oesophageal intubation or dilatation. The incidence of perforation following both diagnostic and therapeutic upper gastrointestinal endoscopy has not changed over the past 10 years. The risk factors are numerous but this audit demonstrated that inexperience increases the likelihood of perforation.
To determine the effect of Helicobacter pylori eradication with omeprazole and amoxycillin, with ... more To determine the effect of Helicobacter pylori eradication with omeprazole and amoxycillin, with or without metronidazole, on the 12-month course of duodenal ulcer disease. In a randomized; double-blind study, conducted in 19 hospitals, 105 H. pylori positive duodenal ulcer patients were healed and symptom-free following either omeprazole dual therapy (omeprazole 40 mg o.m.+amoxycillin 500 mg t.d.s., OA, eradication rate 46%, n = 52) or omeprazole triple therapy (omeprazole 40 mg o.m.+amoxycillin 500 mg t.d.s.+metronidazole 400 mg t.d.s., OAM, eradication rate 92%, n = 53) for 2 weeks, followed by 2 weeks of omeprazole 20 mg o.m. and a 12-month untreated follow-up period, after which time all patients were endoscoped. Endoscopic and symptomatic relapse rates, and effect on H. pylori status measured using 13C-urea breath test, were determined. During the 12-month untreated follow-up period, the life-table endoscopic relapse rates were 12% (95% CI: 2-22%) and 2% (95% CI: 0-6%) for OA and OAM patients, respectively. By 12 months, life-table symptomatic relapse rates were 22% (95% CI: 13-37%) and 19% (95% CI: 8-30%) for OA and OAM, respectively. In the 12 months untreated follow-up period, 2/69 (3%, 95% CI: 0-7%) patients rendered H. pylori negative had an endoscopic relapse at the end of the 12-month follow-up period, compared with 5/31 (16%, 95% CI: 3-29%) patients remaining H. pylori positive (P = 0.03 between H. pylori positive and negative groups). Twelve of 69 (17%, 95% CI: 8-26%) patients rendered H. pylori negative relapsed symptomatically, compared with 9/31 (29%, 95% CI: 13-45%) patients remaining H. pylori positive (P = N.S. between groups). There was a significant improvement in epigastric pain (P = 0.0001), nausea and vomiting (P &amp;amp;amp;amp;lt; 0.05) between entry to the study and 1, 6 and 12 months post-treatment for both treatment groups. OAM eradicates H. pylori in significantly more patients than OA, but successful H. pylori eradication with either OAM or OA predisposes to low endoscopic and symptomatic relapse rates for duodenal ulcer patients when followed up for 12 months.
A prospective audit of upper gastrointestinal endoscopy in 36 hospitals across two regions provid... more A prospective audit of upper gastrointestinal endoscopy in 36 hospitals across two regions provided data from 14149 gastroscopies of which 1113 procedures were therapeutic and 13 036 were diagnostic. Most patients received gastroscopy under intravenous sedation; midazolam was the preferred agent in the North West and diazepam was preferred in East Anglia. Mean doses ofeach agent used were 5 7 mg and 13.8 mg respectively, although there was a wide distribution of doses reported. Only half of the patients endoscoped had some form of intravenous access in situ and few were supplied with supplementary oxygen. The death rate from this study for diagnostic endoscopy was 1 in 2000 and the morbidity rate was 1 in 200; cardiorespiratory complications were the most prominent in this group and there was a strong relation between the lack of monitoring and use of high dose benzodiazepines and the occurrence of adverse outcomes. In particular there was a link between the use of local anaesthetic sprays and the development of pneumonia after gastroscopy (p<0.001). Twenty perforations occurred out of a total of 774 dilatations of which eight patients died (death rate 1 in 100). A number of units were found to have staffing problems, to be lacking in basic facilities, and to have poor or virtually non-existent recovery areas. In addition, a number of junior endoscopists were performing endoscopy unsupervised and with minimal training. (Gut 1995; 36: 462-467) Despite the assumption by many doctors that upper gastrointestinal endoscopy has become both safe and suitable for all patients, recent reports continue to show that complications with upper gastrointestinal endoscopy are occurring at a comparatively consistent rate. 2 As the number of elderly and high risk patients subjected to the procedure increases, the number of cardiopulmonary complications rises in parallel.3 Sedation techniques are probably responsible for some of the medical complications seen, but operator inexperience, and lack of monitoring may also be important. This audit has been designed to investigate how often problems occur at the time of upper gastrointestinal endoscopy and for a 30 day period after the procedure, and to explore common variables in endoscopy practice when such complications occur. The audit has included all flexible diagnostic and therapeutic fibreoptic upper gastrointestinal endoscopy and has excluded rigid oesophagoscopy and endoscopic retrograde cholangiopancreatography. It is hoped that the findings of this study will encourage endoscopists to examine their own practices and thus reduce complication rates associated with endoscopy.
Twenty-four Helicobacter pylori (H. pylori)-positive patients were treated for 28 days with eithe... more Twenty-four Helicobacter pylori (H. pylori)-positive patients were treated for 28 days with either 20 mg omeprazole o.m. (n= 12) or 40 mg omeprazole o.m. (n= 12). Clearance (absence of H. pylori at the end of or shortly after treatment) and eradication (absence of H. pylori 1 month after cessation of treatment) were assessed using the 14C-urea breath test. Observed clearance and eradication were: 20 mg omeprazole 3/12 and 0/12; 40 mg omeprazole 6/12 and 1/12 respectively. The effect on H. pylori is probably due to the change in gastric pH from acid to neutral, however it is insufficient to recommend the inclusion of omeprazole in regimens aimed at eradicating H. pylori.
Ileal disease or resection causes bile salt malabsorption and a reduction in the bile salt conten... more Ileal disease or resection causes bile salt malabsorption and a reduction in the bile salt content of bile. Since cholesterol solubility requires adequate bile salt concentrations, depletion of the bile salt content of bile might, therefore, jeopardize cholesterol solubility and predispose to cholesterol gallstone formation.
0 0 80 e 0 .3 -5 o 0 0~~~~0 o 0 2^0 . 32 33 34 35 36 37 38 39 40 4[ 42 43 Duration of pregnancy a... more 0 0 80 e 0 .3 -5 o 0 0~~~~0 o 0 2^0 . 32 33 34 35 36 37 38 39 40 4[ 42 43 Duration of pregnancy at onset of labour (weeks) FIG. 2.-Birth weights of individual infants in both groups related to gestational age (completed weeks).
Poster based on material presented at the XVIII Annual Board Game Studies Colloquium, Swiss Museu... more Poster based on material presented at the XVIII Annual Board Game Studies Colloquium, Swiss Museum of Games, La Tour-de-Peilz, Switzerland, April 2015.
At the 1990 World Congresses of Gastroenterology, the Working Party on Helicobacter pylori (H. py... more At the 1990 World Congresses of Gastroenterology, the Working Party on Helicobacter pylori (H. pylori) recommended that, in suitable patients, the bacterium should be eradicated using a therapeutic regimen comprising a bismuth salt, tetracycline and metronidazole for two weeks. We have treated 40 patients infected with H. pylori with‘triple’ therapy consisting of 120 mg tripotassium dicitrato bismuthate q.d.s., 500 mg tetracycline q.d.s. and 400 mg metronidazole t.d.s. for two weeks.The success rate, in terms of bacterial eradication, was 19/21 (90.5%) in patients with metronidazole-sensitive organisms, compared with only 6/19 (31.6%) in patients whose H. pylori were resistant to metronidazole (P < 0.01). Side effects, particularly diarrhoea and vomiting/nausea, were common: 23/40 patients reported such symptoms during the 14-day course of therapy. Fifteen of these 23 patients completed the entire 14-day course, although suffering from significant side effects, while the remaining eight patients had to discontinue the treatment because side effects became intolerable.If a form of triple therapy is going to be widely used to eradicate H. pylori infection, the regimen will have to be simpler, shorter, produce fewer side effects and be more effective in patients with metronidazole-resistant bacteria.
The vigorous debate over whom to sedate, when to sedate, and how to sedate shows no sign of runni... more The vigorous debate over whom to sedate, when to sedate, and how to sedate shows no sign of running out of steam. There is a general consensus that patients should be more involved in the decision-making process for the sedation &amp;amp;amp;amp;quot;menu&amp;amp;amp;amp;quot;. A move away from the take-it-or-leave-it attitude of all or nothing to an &amp;amp;amp;amp;quot;à la carte&amp;amp;amp;amp;quot; choice is to be encouraged. A new textbook and several further guidelines have appeared. The particular problems associated with sedating the elderly are briefly presented. The pros and cons of using local pharyngeal anaesthesia are discussed. Enthusiasm for the use of intravenous propofol is gathering momentum, despite continuing worries about its safety in the hands of the nonanaesthetist. For many endoscopists, the combination of a benzodiazepine plus (or minus) an opioid with which they are most familiar is still the best compromise in terms of efficacy, cost, and safety. Fatal drug-induced cardiopulmonary complications continue to occur, despite a general trend toward using smaller doses of sedation than we did 5 - 10 years ago. Monitoring techniques that are at present considered as research tools may one day become commonplace. These include: the use of an electroencephalography parameter known as bispectral analysis; transcutaneous CO(2) measurement; and a modified continuous capnographic waveform trace to monitor ventilatory effort. Bispectral analysis may be of use in monitoring central nervous system depression and helping to distinguish between conscious sedation and deep sedation. If the measurement of CO(2) levels, either transcutaneously or in breath samples, was as easy and inexpensive as measuring SpO(2) with a pulse oximeter, then undoubtedly such technology would enhance the early detection of sedative-induced hypoventilation and apnoea. Further evidence regarding droperidol&amp;amp;amp;amp;#39;s possible role in conscious sedation is presented. Pain during colonoscopy remains a problem, and the possible role for intraluminal injection of peppermint oil, as well as the value of variable-stiffness colonoscopes, in reducing the need for intravenous sedation is discussed. Case reports of hyponatraemic encephalopathy and hypocalcaemic tetany as complications of oral bowel preparation are presented, as is the challenge associated with adequate bowel preparation in diabetic patients.
IEEE Transactions on Instrumentation and Measurement, 2007
This paper proposes a novel method of using electromyographic (EMG) potentials generated by the f... more This paper proposes a novel method of using electromyographic (EMG) potentials generated by the forearm muscles during hand and finger movements to control an artificial prosthetic hand worn by an amputee. Surface EMG sensors were used to record a sequence of forearm EMG potential signals via a PC sound card and a novel 3-D electromagnetic positioning system together with a data-glove mounted with 11 miniature electromagnetic sensors used to acquire corresponding human hand pose in real time. The synchronized measurements of hand posture and associated EMG signals stored as prototypes embody a numerical expression of the current hand shape in the form of a series of data frames, each comprising a set of postures and associated EMG data. This allows a computer generated graphical 3-D model, combined with synthesized EMG signals, to be used to evaluate the approach. This graphical user interface could also enable handicapped users to practice controlling a robotic prosthetic hand using EMG signals derived from their forearm muscles. We believe this task might be made easier using a dictionary of stored task-specific prototype data frames acquired from able-bodied users. By comparing the resulting EMG data frames with stored prototypes, the most likely data frame sequence can be identified and used to control a robotic hand so that it carries out the user's desire. We explore the feasibility of this approach by applying frequency analysis on the signal derived from a multichannel EMG measurement device and identify pattern recognition techniques in the time and frequency domains to determine plausible hand shapes. This approach offers several advantages over existing methods. First, it simplifies the classification procedure, saving computational time and the requirement for the optimization process, and second, it increases the number of recognizable hand shapes, which in turn improves the dexterity of the prosthetic hand and the quality of life for amputees. The database of EMG prototypes could be employed to optimize the accuracy of the system within a machine learning paradigm. By making a range of EMG prototype databases available, prosthetic hand users could train themselves to use their prosthesis using the visual reference afforded by the virtual hand model to provide feedback.
After cardiopulmonary complications, perforation is the second most important cause of complicati... more After cardiopulmonary complications, perforation is the second most important cause of complications following flexible upper gastrointestinal endoscopy. A recent audit of 14149 procedures detected a perforation rate of 0.05 per cent (overall mortality rate 0.008 per cent) during diagnostic endoscopy, and a perforation rate of 2.6 percent (overall mortality rate 1.0 per cent) following oesophageal intubation or dilatation. The incidence of perforation following both diagnostic and therapeutic upper gastrointestinal endoscopy has not changed over the past 10 years. The risk factors are numerous but this audit demonstrated that inexperience increases the likelihood of perforation.
To determine the effect of Helicobacter pylori eradication with omeprazole and amoxycillin, with ... more To determine the effect of Helicobacter pylori eradication with omeprazole and amoxycillin, with or without metronidazole, on the 12-month course of duodenal ulcer disease. In a randomized; double-blind study, conducted in 19 hospitals, 105 H. pylori positive duodenal ulcer patients were healed and symptom-free following either omeprazole dual therapy (omeprazole 40 mg o.m.+amoxycillin 500 mg t.d.s., OA, eradication rate 46%, n = 52) or omeprazole triple therapy (omeprazole 40 mg o.m.+amoxycillin 500 mg t.d.s.+metronidazole 400 mg t.d.s., OAM, eradication rate 92%, n = 53) for 2 weeks, followed by 2 weeks of omeprazole 20 mg o.m. and a 12-month untreated follow-up period, after which time all patients were endoscoped. Endoscopic and symptomatic relapse rates, and effect on H. pylori status measured using 13C-urea breath test, were determined. During the 12-month untreated follow-up period, the life-table endoscopic relapse rates were 12% (95% CI: 2-22%) and 2% (95% CI: 0-6%) for OA and OAM patients, respectively. By 12 months, life-table symptomatic relapse rates were 22% (95% CI: 13-37%) and 19% (95% CI: 8-30%) for OA and OAM, respectively. In the 12 months untreated follow-up period, 2/69 (3%, 95% CI: 0-7%) patients rendered H. pylori negative had an endoscopic relapse at the end of the 12-month follow-up period, compared with 5/31 (16%, 95% CI: 3-29%) patients remaining H. pylori positive (P = 0.03 between H. pylori positive and negative groups). Twelve of 69 (17%, 95% CI: 8-26%) patients rendered H. pylori negative relapsed symptomatically, compared with 9/31 (29%, 95% CI: 13-45%) patients remaining H. pylori positive (P = N.S. between groups). There was a significant improvement in epigastric pain (P = 0.0001), nausea and vomiting (P &amp;amp;amp;amp;lt; 0.05) between entry to the study and 1, 6 and 12 months post-treatment for both treatment groups. OAM eradicates H. pylori in significantly more patients than OA, but successful H. pylori eradication with either OAM or OA predisposes to low endoscopic and symptomatic relapse rates for duodenal ulcer patients when followed up for 12 months.
A prospective audit of upper gastrointestinal endoscopy in 36 hospitals across two regions provid... more A prospective audit of upper gastrointestinal endoscopy in 36 hospitals across two regions provided data from 14149 gastroscopies of which 1113 procedures were therapeutic and 13 036 were diagnostic. Most patients received gastroscopy under intravenous sedation; midazolam was the preferred agent in the North West and diazepam was preferred in East Anglia. Mean doses ofeach agent used were 5 7 mg and 13.8 mg respectively, although there was a wide distribution of doses reported. Only half of the patients endoscoped had some form of intravenous access in situ and few were supplied with supplementary oxygen. The death rate from this study for diagnostic endoscopy was 1 in 2000 and the morbidity rate was 1 in 200; cardiorespiratory complications were the most prominent in this group and there was a strong relation between the lack of monitoring and use of high dose benzodiazepines and the occurrence of adverse outcomes. In particular there was a link between the use of local anaesthetic sprays and the development of pneumonia after gastroscopy (p<0.001). Twenty perforations occurred out of a total of 774 dilatations of which eight patients died (death rate 1 in 100). A number of units were found to have staffing problems, to be lacking in basic facilities, and to have poor or virtually non-existent recovery areas. In addition, a number of junior endoscopists were performing endoscopy unsupervised and with minimal training. (Gut 1995; 36: 462-467) Despite the assumption by many doctors that upper gastrointestinal endoscopy has become both safe and suitable for all patients, recent reports continue to show that complications with upper gastrointestinal endoscopy are occurring at a comparatively consistent rate. 2 As the number of elderly and high risk patients subjected to the procedure increases, the number of cardiopulmonary complications rises in parallel.3 Sedation techniques are probably responsible for some of the medical complications seen, but operator inexperience, and lack of monitoring may also be important. This audit has been designed to investigate how often problems occur at the time of upper gastrointestinal endoscopy and for a 30 day period after the procedure, and to explore common variables in endoscopy practice when such complications occur. The audit has included all flexible diagnostic and therapeutic fibreoptic upper gastrointestinal endoscopy and has excluded rigid oesophagoscopy and endoscopic retrograde cholangiopancreatography. It is hoped that the findings of this study will encourage endoscopists to examine their own practices and thus reduce complication rates associated with endoscopy.
Twenty-four Helicobacter pylori (H. pylori)-positive patients were treated for 28 days with eithe... more Twenty-four Helicobacter pylori (H. pylori)-positive patients were treated for 28 days with either 20 mg omeprazole o.m. (n= 12) or 40 mg omeprazole o.m. (n= 12). Clearance (absence of H. pylori at the end of or shortly after treatment) and eradication (absence of H. pylori 1 month after cessation of treatment) were assessed using the 14C-urea breath test. Observed clearance and eradication were: 20 mg omeprazole 3/12 and 0/12; 40 mg omeprazole 6/12 and 1/12 respectively. The effect on H. pylori is probably due to the change in gastric pH from acid to neutral, however it is insufficient to recommend the inclusion of omeprazole in regimens aimed at eradicating H. pylori.
Ileal disease or resection causes bile salt malabsorption and a reduction in the bile salt conten... more Ileal disease or resection causes bile salt malabsorption and a reduction in the bile salt content of bile. Since cholesterol solubility requires adequate bile salt concentrations, depletion of the bile salt content of bile might, therefore, jeopardize cholesterol solubility and predispose to cholesterol gallstone formation.
0 0 80 e 0 .3 -5 o 0 0~~~~0 o 0 2^0 . 32 33 34 35 36 37 38 39 40 4[ 42 43 Duration of pregnancy a... more 0 0 80 e 0 .3 -5 o 0 0~~~~0 o 0 2^0 . 32 33 34 35 36 37 38 39 40 4[ 42 43 Duration of pregnancy at onset of labour (weeks) FIG. 2.-Birth weights of individual infants in both groups related to gestational age (completed weeks).
Poster based on material presented at the XVIII Annual Board Game Studies Colloquium, Swiss Museu... more Poster based on material presented at the XVIII Annual Board Game Studies Colloquium, Swiss Museum of Games, La Tour-de-Peilz, Switzerland, April 2015.
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Papers by Duncan Bell
Posters by Duncan Bell