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J Dent

Publications and source records attributed to J Dent.

At least 73 records · Page 4Linked to original sources
PubMed2000

Evaluation of multiple-point measurement of sphincter of Oddi motility in the Australian brush-tailed possum.

Manometric assembly diameter is a major limitation on the number of perfused manometric recording points for recordings from the sphincter of Oddi (SO). We evaluated novel polyimide manometric assemblies whereby four recording channels were incorporated in an overall assembly diameter of 0.8 mm. Over the very low range of perfusion rates tested (0.005-0.04 ml/min), the assemblies had pressure offsets attributable to water perfusion from 2 to 23 mmHg and pressure rise rates from 20 to 163 mmHg/s. In six anesthetized Australian brush-tailed possums, manometric recordings from the SO showed a significant reduction in the recorded peak amplitude of pressure waves with perfusion rates below 0.02 ml/min. The pressure profile of the sphincter was found to be asymmetric, and phasic wave propagation patterns were complex (antegrade 35.6%, "mixed" 64.4%). In conclusion, accurate multipoint SO manometry in the possum can be performed with micromanometric assemblies at very low perfusion rates to give a more complete understanding of SO mechanics. These methods are also potentially applicable to perfusion manometry in other small laboratory animals such as mice.

Animals↗
PubMed2000

Efficient utilization of echocardiography for the assessment of left ventricular systolic function.

BACKGROUND: We hypothesized that patients could be selected for echocardiographic evaluation of left ventricular (LV) systolic function on the basis of historic, clinical, radiographic, and electrocardiographic criteria. METHODS AND RESULTS: We prospectively evaluated 300 consecutive inpatients referred for the echocardiographic assessment of LV function, of whom 124 (41%) had LV systolic dysfunction (LVSD) (LV ejection fraction <0.45). Among the historic variables, male sex was the only predictor of LVSD, whereas of the abnormal physical and radiographic findings, cardiomegaly on chest radiography was the only predictor. Among the electrocardiographic findings, the presence of left bundle branch block was positively correlated with the presence of LVSD, whereas a normal electrocardiogram was negatively correlated with this finding. Only 2 patients with LVSD had a normal electrocardiogram. The addition of significant predictors on physical examination and chest radiography doubled the predictive value of the historic variables for determining LVSD. The addition of electrocardiographic findings further doubled the predictive value of the model. Almost 45% of the predictive power of the final multivariate model (chi-square of 48 of the total chi-square of 108) was based on the absence of normal electrocardiogram in patients with LVSD. When chest radiographic findings were excluded from the model, the overall predictive power of the model did not change, with the normal electrocardiogram gaining greater prominence: Full 56% of the predictive power of the model (chi-square of 60 of the total chi-square of 108) resided in the ability of a normal electrocardiogram to discriminate between patients with and those without LVSD. CONCLUSIONS: Historic, chest radiographic, and electrocardiographic variables can be used to predict low likelihood of LVSD on echocardiography. In particular, when the electrocardiogram is normal, it is extremely unlikely to have LVSD. It can be argued that such patients should not be referred for echocardiography.

Aged↗
PubMed1999

A comparison of transnasal and transoral endoscopy with small-diameter endoscopes in unsedated patients.

BACKGROUND: The aim of this study was to compare use and tolerance of transnasal and transoral diagnostic endoscopy with small-diameter endoscopes in unsedated patients. METHODS: Patients being seen for diagnostic endoscopy were randomly assigned to have an unsedated transnasal or transoral procedure. Two prototype narrow-diameter endoscopes (a 5.3 mm fiberoptic endoscope and a 5.9 mm videoendoscope) were used. RESULTS: Of 170 patients (64 women and 106 men) enrolled, 86 underwent transoral and 84 underwent transnasal endoscopy. The procedure was successfully completed using the transoral route in 85 of 86 patients and using the transnasal route in 74 of 84 patients (p = 0.004). Sixteen patients experienced mild epistaxis after transnasal endoscopy. The larger videoendoscope, when compared with the fiberoptic endoscope, accounted for a significantly higher proportion of failures (8 of 41 vs. 2 of 43, p = 0.046) and cases of epistaxis (12 of 33 vs. 4 of 41, p = 0.007). The time taken for transoral endoscopy was shorter than the transnasal route (oral mean 13.7 +/- 0.5 minutes, nasal mean 15.2 +/- 0.6 minutes, p = 0.054). There was no difference between the 2 groups with respect to tolerance of the procedure. From the endoscopist's perspective, the only statistically significant difference between the 2 groups was that endoscope insertion was easier by the oral route (p = 0.007). CONCLUSIONS: Unsedated transnasal endoscopy with the videoendoscope was less successful compared with the transnasal fiberoptic instrument or when compared with either instrument passed transorally. Use of the larger diameter videoendoscope also resulted in significantly more epistaxis in the transnasal endoscopy group. Endoscopists find transoral introduction of the endoscope easier; this may reflect their relative unfamiliarity with the nasal route. Once intubation has been successfully achieved for either route, patient tolerance is the same.

Adult↗
PubMed1999

Mechanism of gastroesophageal reflux in premature infants with chronic lung disease.

BACKGROUND/PURPOSE: The aim of this study was to characterize the motor events responsible for gastroesophageal reflux (GER) and esophageal acid clearance in a cohort of preterm infants with chronic lung disease (CLD). METHODS: Esophageal motility was recorded for 2 to 3 hours postprandially in 14 preterm infants with mild-moderate or moderate-severe CLD at 33 to 39 weeks postmenstrual age using a sleeve-side hole micromanometric assembly into which a pH probe had been installed. RESULTS: Twenty-six acid GER episodes were recorded by pH probe. Of these, 22 (85%) were associated with transient lower esophageal sphincter (LES) relaxation. Transient LES relaxations were significantly longer in duration than single swallows (13.7 seconds v 4.6 seconds, P < .001) and had lower nadir pressures (1.1 mm Hg v 2.5 mm Hg, P < .001). During periods of esophageal acidification (pH below 4), peristaltic esophageal body pressure wave sequences cleared acid refluxate more effectively than nonperistaltic pressure wave sequences. CONCLUSIONS: In preterm infants with CLD, transient LES relaxations are the predominant mechanism underlying GER, and esophageal clearance mechanisms are fully functional, which is similar to that seen in healthy preterm infants.

Chronic Disease↗
PubMed1999

Characterization of esophageal body and lower esophageal sphincter motor function in the very premature neonate.

OBJECTIVES: To characterize esophageal body and lower esophageal sphincter (LES) motor function in very premature infants. STUDY DESIGN: Esophageal manometry was performed in 12 very premature infants of 26 to 33 weeks' postmenstrual age (PMA) (body weights of 610-1360 g). Esophageal motor patterns were recorded for 30 minutes with a perfused micromanometric sleeve assembly (outer diameter, 2.0 mm). RESULTS: Esophageal pressure waves triggered by dry swallows were predominantly (84%) peristaltic in propagation sequence. All infants showed tonic LES contraction; the mean resting LES pressure (LESP) for individual infants ranged from 5.0 +/- 4.1 mm Hg to 20.0 +/- 4.8 mm Hg. In all infants the LES relaxed (duration, 5.8 +/- 3.0 seconds; nadir pressure, 1.8 +/- 2.6 mm Hg) in response to pharyngeal swallows. Transient LES relaxations (TLESRs) (duration, 21.7 +/- 8.7 seconds; nadir pressure, 0.1 +/- 1.8 mm Hg) occurred on average 2.6 +/- 1.6 times per study; 86% of these relaxations triggered esophageal body common cavity events known to be associated with gastroesophageal reflux. CONCLUSIONS: Esophageal motor function is well developed in very premature infants. Our data also suggest that TLESR is the predominant mechanism of reflux in these babies.

Esophagogastric Junction↗
PubMed1999

Lower esophageal sphincter position in premature infants cannot be correctly estimated with current formulas.

OBJECTIVES: Strobel's formula (Esophageal length = 5 + 0.252 x Height) is frequently used as a guide for determining the distance from the nares to the lower esophageal sphincter (LES) in term infants. The aim of this study was to examine this relationship in premature infants. STUDY DESIGN: The distance from nares to LES was manometrically determined in 156 premature infants (26-40 weeks' postmenstrual age; body weights of 610-3050 g). The ability of body weight, height (body length), head circumference, and postmenstrual age to predict the manometrically determined LES position was evaluated with linear and non-linear regression analyses. RESULTS: Body weight and body length were the most predictive of distance from nares to LES (r(2) = 0.848 and 0.802, respectively). These relationships were non-linear and, in the case of body length, deviated substantially from Strobel's model. CONCLUSIONS: In premature neonates, a different formula is needed for prediction of the distance between nares and LES than that applied to term infants and children.

Anthropometry↗
PubMed1999

Manual-assisted cognitive-behaviour therapy (MACT): a randomized controlled trial of a brief intervention with bibliotherapy in the treatment of recurrent deliberate self-harm.

BACKGROUND: The treatment of deliberate self-harm (parasuicide) remains limited in efficacy. Despite a range of psychosocial, educational and pharmacological interventions only one approach, dialectical behaviour therapy, a form of cognitive-behaviour therapy (CBT), has been shown to reduce repeat episodes, but this is lengthy and intensive and difficult to extrapolate to busy clinical practice. We investigated the effectiveness of a new manual-based treatment varying from bibliotherapy (six self-help booklets) alone to six sessions of cognitive therapy linked to the booklets, which contained elements of dialectical behaviour therapy. METHODS: Thirty-four patients, aged between 16 and 50, seen after an episode of deliberate self-harm, with personality disturbance within the flamboyant cluster and a previous parasuicide episode within the past 12 months, were randomly assigned to treatment with manual-assisted cognitive-behaviour therapy (MACT N = 18) or treatment as usual (TAU N = 16). Assessment of clinical symptoms and social function were made at baseline and repeated by an independent assessor masked to treatment allocation at 6 months. The number and rate of all parasuicide attempts, time to next episode and costs of care were also determined. RESULTS: Thirty-two patients (18 MACT; 14 TAU) were seen at follow-up and 10 patients in each group (56% MACT and 71% TAU) had a suicidal act during the 6 months. The rate of suicidal acts per month was lower with MACT (median 0.17/month MACT; 0.37/month TAU; P = 0.11) and self-rated depressive symptoms also improved (P = 0.03). The treatment involved a mean of 2.7 sessions and the observed average cost of care was 46% less with MACT (P = 0.22). CONCLUSIONS: Although limited by the small sample, the results of this pilot study suggest that this new form of cognitive-behaviour therapy is promising in its efficacy and feasible in clinical practice.

Adolescent↗
PubMed1999

Characterization of small intestinal pressure waves in ambulant subjects recorded with a novel portable manometric system.

The organization of lumen-occlusive pressure waves is believed to be an important determinant of luminal flow. At present, little is known about the organization of small intestinal pressure waves in humans. The aim of the present study was to characterize the spatiotemporal organization of small intestinal pressure waves using a portable 12-channel micromanometric system. Small intestinal pressures were recorded from six duodenal (1 cm apart) and six jejunal (1 cm apart) sites after a standard lunch (1892 kJ) and dinner (3305 kJ) and an overnight fast in seven ambulant subjects. Postprandially, the number of isolated pressure waves and the number of pressure wave sequences that spanned 1 and 2 cm decreased over time (P = 0.04, P = 0.003, and P = 0.0001) and were higher after lunch than dinner (P = 0.04, P = 0.02 and P = 0.04), in contrast to the number of long-spanned pressure wave sequences, which remained constant over time and were not influenced by the meal. The number of isolated pressure waves and pressure wave sequences over 1-5 cm recorded in the early postprandial period were higher than during the 30-min period of nocturnal phase II (P < 0.01). In conclusion, prolonged recording of small intestinal motility in ambulant subjects using a perfused manometric system is feasible. Postprandial recordings showed that the spatiotemporal organization of pressure waves is time- and meal-dependent.

Adult↗
PubMed1999

Helicobacter pylori and reflux disease.

Currently, the influence of Helicobacter pylori infection on gastro-oesophageal reflux disease is a major focus of attention because it is an issue that is relevant to so many patients. There is accumulating evidence that it is the severity of H. pylori-induced gastritis that determines whether clinically relevant effects occur within individual patients. Several lines of evidence suggest that there is a protective effect against reflux disease if gastritis is severe enough to cause elevation of gastric pH above 3 for significant parts of the 24 h cycle. Conversely, H. pylori eradication would be expected to increase the risk of reflux disease if previously substantially reduced acid secretion recovers significantly as a result of healing of corpus gastritis. This analysis indicates that the interaction of H. pylori and reflux disease should differ for duodenal ulcer patients, who do not have major reductions of acid secretion, and for gastric ulcer or atrophic gastritis patients, who do. Available data that have assessed the effects of H. pylori eradication are especially difficult to interpret in patients with chronic peptic ulcer, because of several important confounding factors. In the case of duodenal ulcer, the available studies are very conflicting, and few have been published in full. For the most relevant patient group, those whose primary problem is reflux disease, there are currently no data available on the effects of H. pylori eradication.

Adenocarcinoma↗
PubMed1999

Effect of cisapride on secondary peristalsis in patients with gastroesophageal reflux disease.

OBJECTIVE: Improvement of esophageal acid clearance appears to be an important effect of cisapride in the treatment of reflux disease. The mechanism underlying this effect is not clear. Esophageal peristalsis is a major component of the acid clearance process. In normal subjects secondary peristalsis is an important mechanism of esophageal acid clearance during sleep, and this response appears to be impaired in patients with reflux esophagitis. The effects of cisapride on secondary peristalsis are not known. The aim of this study was to investigate the effects of cisapride on the triggering and characteristics of secondary peristalsis in patients with reflux esophagitis. METHODS: In 17 patients with reflux esophagitis and impaired secondary peristalsis cisapride, 10 mg q.i.d., or placebo were administered in a randomized double blind, crossover design for 4 days separated by a 4-7 day washout period. On the fourth day of treatment, primary peristalsis and secondary peristalsis in response to 10- and 20-ml air boluses were assessed. RESULTS: Secondary peristaltic success and amplitude were greater with the 20-ml bolus than with the 10-ml bolus. However, cisapride had no effect on either secondary peristaltic success or amplitude. Cisapride also had no effect on primary peristalsis or basal LES pressure. CONCLUSIONS: The improvement in esophageal acid clearance by cisapride is not explainable by improvement in secondary peristalsis.

Adult↗
PubMed1999

Preservation of postural control of transient lower oesophageal sphincter relaxations in patients with reflux oesophagitis.

INTRODUCTION: In normal subjects, transient lower oesophageal sphincter relaxations (TLOSRs) and gas reflux during belching are suppressed in the supine position. Supine reflux, however, is a feature of reflux disease. AIMS: To investigate whether postural suppression of TLOSRs and gas reflux is impaired in patients with reflux disease. PATIENTS: Ten patients with erosive oesophagitis. METHODS: Oesophageal manometry was performed during gastric distension with 750 ml carbon dioxide. Measurements were made for 10 minutes before and after distension in both sitting and supine positions. RESULTS: In the sitting position gastric distension substantially increased the rate of gas reflux (median (interquartile range)), as evidenced by increases in oesophageal common cavities from 1 (0-1)/10 min to 7 (5-10)/10 min and TLOSRs from 1 (1-1.5)/10 min to 6 (2.5-8)/10 min. However, this effect was suppressed in the supine position in all but one patient (TLOSRs 0 (0)/10 min to 1 (0-4.5)/10 min, common cavities 0 (0)/10 min to 0.5 (0-2)/10 min). CONCLUSIONS: Postural suppression of TLOSRs and gas reflux is generally preserved in reflux disease.

Adult↗
PubMed1999

Endoscopic assessment of oesophagitis: clinical and functional correlates and further validation of the Los Angeles classification.

BACKGROUND: Endoscopic oesophageal changes are diagnostically helpful and identify patients exposed to the risk of disease chronicity. However, there is a serious lack of agreement about how to describe and classify the appearance of reflux oesophagitis AIMS: To examine the reliability of criteria that describe the circumferential extent of mucosal breaks and to evaluate the functional and clinical correlates of patients with reflux disease whose oesophagitis was graded according to the Los Angeles system. METHODS: Forty six endoscopists from different countries used a detailed worksheet to evaluate endoscopic video recordings from 22 patients with the full range of severity of reflux oesophagitis. In separate studies, Los Angeles system gradings were correlated with 24 hour oesophageal pH monitoring (178 patients), and with clinical trials of omeprazole treatment (277 patients). RESULTS: Evaluation of circumferential extent of oesophagitis by the criterion of whether mucosal breaks extended between the tops of mucosal folds, gave acceptable agreement (mean kappa value 0.4) among observers. This approach is used in the Los Angeles system. An alternative approach of grouping the circumferential extent of mucosal breaks as occupying 0-25%, 26-50%, 51-75%, 76-99%, or 100% of the oesophageal circumference, gave unacceptably high interobserver variation (mean kappa values 0-0.15) for all but the lowest category of extent (mean kappa value 0.4). Severity of oesophageal acid exposure was significantly (p<0.001) related to the severity grade of oesophagitis. Preteatment oesophagitis grades A-C were related to heartburn severity (p<0.01), outcomes of omeprazole (10 mg daily) treatment (p<0.01), and the risk for symptom relapse off therapy over six months (p<0.05). CONCLUSIONS: Results add further support to previous studies for the clinical utility of the Los Angeles system for endoscopic grading of oesophagitis.

Endoscopy, Digestive System↗
PubMed1999

Effects of duodenal distension on antropyloroduodenal pressures and perception are modified by hyperglycemia.

Marked hyperglycemia (blood glucose approximately 15 mmol/l) affects gastrointestinal motor function and modulates the perception of gastrointestinal sensations. The aims of this study were to evaluate the effects of mild hyperglycemia on the perception of, and motor responses to, duodenal distension. Paired studies were done in nine healthy volunteers, during euglycemia ( approximately 4 mmol/l) and mild hyperglycemia ( approximately 10 mmol/l), in randomized order, using a crossover design. Antropyloroduodenal pressures were recorded with a manometric, sleeve-side hole assembly, and proximal duodenal distensions were performed with a flaccid bag. Intrabag volumes were increased at 4-ml increments from 12 to 48 ml, each distension lasting for 2.5 min and separated by 10 min. Perception of the distensions and sensations of fullness, nausea, and hunger were evaluated. Perceptions of distension (P < 0.001) and fullness (P < 0.05) were greater and hunger less (P < 0.001) during hyperglycemia compared with euglycemia. Proximal duodenal distension stimulated pyloric tone (P < 0.01), isolated pyloric pressure waves (P < 0.01), and duodenal pressure waves (P < 0.01). Compared with euglycemia, hyperglycemia was associated with increases in pyloric tone (P < 0.001), the frequency (P < 0.05) and amplitude (P < 0.01) of isolated pyloric pressure waves, and the frequency of duodenal pressure waves (P < 0.001) in response to duodenal distension. Duodenal compliance was less (P < 0.05) during hyperglycemia compared with euglycemia, but this did not account for the effects of hyperglycemia on perception. We conclude that both the perception of, and stimulation of pyloric and duodenal pressures by, duodenal distension are increased by mild hyperglycemia. These observations are consistent with the concept that the blood glucose concentration plays a role in the regulation of gastrointestinal motility and sensation.

Adult↗
PubMed1999

Validation of a novel luminal flow velocimeter with video fluoroscopy and manometry in the human esophagus.

There is currently no ideal method for concurrently assessing intraluminal pressures and flows in humans with high temporal resolution. We have developed and assessed the performance of a novel fiber-optic laser-Doppler velocimeter, mounted in a multichannel manometric assembly. Velocimeter recordings were compared with concurrent fluoroscopy and manometry following 50 barium swallows in healthy subjects. During these swallows, the velocimeter sensor was situated in either the proximal (24 swallows) or the distal (26 swallows) esophagus. It signaled intraluminal flow following 46 of 50 swallows. A greater mean number of deflections were recorded in the distal compared with the proximal esophagus (4. 3 vs. 2.4, P = 0.001). The maximal flow velocity recorded did not differ between the proximal and distal esophagus (76.7 vs. 73.8 mm/s). No velocimeter signals commenced after fluoroscopic lumen occlusion. The velocimeter signals were closely temporally related to fluoroscopic barium flow. Upward catheter movement on swallowing sometimes appeared to cause a velocimeter signal. Manometrically "normal" swallows were no different from "abnormal" swallows in the number and velocity of deflections recorded by the velocimeter. This novel instrument measures intraluminal flow velocity and pressures concurrently, thus enabling direct study of pressure-flow relationships. Flow patterns differed between the proximal and distal esophagus.

Adult↗
PubMed1999

Measurement of upper esophageal sphincter tone and relaxation during swallowing in premature infants.

Upper esophageal sphincter (UES) motor function has not been previously evaluated in premature infants. The motor patterns associated with tonic activity and swallow-related relaxation of the UES were recorded for 1 h after completion of gavage feeding in 11 healthy preterm neonates (postmenstrual age 33-37 wk) with a micromanometric assembly, which included a sleeve sensor specifically adapted for UES recordings. A clearly defined UES high-pressure zone was observed in all premature infants studied. Resting UES pressure ranged from 2.3 to 26.2 mmHg and was higher during periods of irritability and apparent discomfort. During dry swallows, UES pressure relaxed from a resting pressure of 28.2 +/- 4.0 mmHg to a nadir of 1.1 +/- 3.3 mmHg. The mean UES relaxation interval (the time from relaxation onset to relaxation offset) was 0. 31 +/- 0.11 s. We conclude that in premature infants >/=33 wk postmenstrual age the motor mechanisms regulating UES resting pressure and the onset of UES relaxation are well developed.

Deglutition↗