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Biomedical subjects

W J Owen

Publications and source records attributed to W J Owen.

At least 19 recordsLinked to original sources
PubMed1998

Scanning laser Doppler flowmetry and intraluminal recirculating gas tonometry in the assessment of gastric and jejunal perfusion during oesophageal resection.

BACKGROUND: The ability of the new techniques of scanning laser Doppler flowmetry and recirculating gas tonometry to measure changes in gastric serosal and mucosal blood flow respectively during oesophageal resection was assessed. METHODS: Changes in regional and total gastric blood flow were assessed in 16 patients undergoing oesophagectomy at three stages of the procedure. Laser Doppler images were analysed and perfusion expressed as mean perfusion units. Tonometric measurements of gastric and jejunal intramucosal pH (pHi) were made synchronously. RESULTS: There were significant falls in gastric perfusion measured with scanning laser Doppler flowmetry in all subjects between each measurement. Mean perfusion of the stomach fell 41 per cent after mobilization. There was a gradient of reduced perfusion between the antrum (mean fall 25 per cent) and the area used for the anastomosis in the fundus (mean fall 55 per cent). Before mobilization mean gastric and jejunal pHi were 7.37 and 7.46 respectively. These fell to 7.18 and 7.37 respectively after mobilization and to 7.29 and 7.38 after anastomosis. CONCLUSION: These new techniques could be employed at operation, appear to overcome the limitations of single-point laser Doppler flowmetry and saline tonometry, and have measured significant changes in gastric perfusion. They may have widespread clinical application.

Adult↗
PubMed1998

What is normal oesophageal motility? An ambulatory study.

BACKGROUND: Our aim was to establish normal values for wave characteristics and patterns in long-term ambulatory oesophageal body motility. METHODS: A pressure sensor was positioned in the pharynx or cricopharyngeus for swallow detection. Oesophageal body pressures were recorded 5, 10, and 15 cm above the lower oesophageal sphincter. Contraction patterns and wave characteristics from eating, drinking, and postprandial, fasting, and supine periods in 16 healthy subjects were studied. RESULTS: Contraction patterns were similar during eating and drinking periods or fasting and postprandial periods (P > 0.05). Wave characteristics during each period differed significantly in amplitude, duration, area under the curve, or peristaltic velocity (P < 0.05). During the eating period the amplitude and area under the curve were greatest, and peristaltic velocity was slowest compared with all other periods. CONCLUSIONS: Data from the eating and drinking periods or the fasting and postprandial periods can be combined for contraction pattern analysis but not for wave characteristic analysis, for which data from different periods should be analysed separately.

Adult↗
PubMed1998

The temporal relationship between oesophageal bile reflux and pH in gastro-oesophageal reflux disease.

OBJECTIVE: Damage caused to oesophageal mucosa by bile constituents is pH dependent. The aim of this study was to evaluate the relationship between pH and duodeno-gastro-oesophageal reflux in gastro-oesophageal reflux disease at night in the supine position. DESIGN: A prospective study of 113 patients with reflux symptoms [63 without erosive oesophagitis (group 1), 23 with erosive oesophagitis (group 2), 27 Barrett's oesophagus (group 3)] and 15 controls. METHODS: All subjects underwent 24 h ambulatory oesophageal pH and bilirubin and gastric pH monitoring. For the supine period, oesophageal pH during episodes of bile reflux was calculated, and the temporal relationship between individual oesophageal and gastric alkaline shift and oesophageal bile reflux episodes was established. The supine period was divided into four equal segments and the temporal patterns of acid and bile reflux and alkaline shift in each of the four supine time segments were investigated. RESULTS: Both acid and bile reflux are severe in Barrett's oesophagus, particularly at night. Nocturnal oesophageal bile reflux occurs mostly between pH 4 and 7 in all groups: 67.6%, 76.5% and 41.4% of the supine period for groups 1, 2 and 3 respectively (P < 0.001 vs. pH < 4 or > 7). Individual oesophageal bile reflux and oesophageal or gastric alkaline shift episodes rarely coincide. Acid reflux predominates in the first half of the night (P < 0.001), oesophageal bile reflux and alkaline shift continue throughout the night, gastric alkaline shift increases towards the end of the night (P < 0.001). CONCLUSION: Duodenal contents in the oesophagus exist at a wide pH range, and may have passed through an acid or an alkaline stomach. This has implications for the damage which individual constituents are able to cause.

Adolescent↗
PubMed1998

A prospective study of oesophageal function in patients with normal coronary angiograms and controls with angina.

AIMS: To compare the incidence of oesophageal abnormalities and their correlation with chest pain in patients with normal coronary angiograms, and in controls with angina. PATIENTS: Sixty one patients with normal coronary angiograms (NCA group) referred to a single cardiac centre between March 1990 and April 1991; 25 matched controls with confirmed coronary artery disease (CAD group). SETTING: Cardiac referral centre and oesophageal function testing laboratory. MAIN OUTCOME MEASURES: Oesophageal manometry, provocation tests, and 24 hour ambulatory pH monitoring. RESULTS: Simultaneous contractions were more common (6.7% versus 0.8%, p < 0.01), and the duration of peristaltic contractions was longer (2.9 versus 2.4 seconds, p < 0.01) in the NCA group than in the CAD group. There were no group differences in the amplitude of peristaltic contractions, and none had nutcracker oesophagus. Ten (16%) patients with NCA and no patients with CAD had diffuse spasm (p = 0.03). Twenty one (34%) patients with NCA, and five (20%) patients with CAD had abnormal gastro-oesophageal reflux (p > 0.05). There was no significant difference between the groups in the number of patients whose pain was temporally related to pH events. Particular chest pain characteristics, or the presence of additional oesophageal symptoms, were not predictive of an oesophageal abnormality. CONCLUSION: Oesophageal function tests commonly implicate the oesophagus as a source of pain in patients with normal coronary angiograms. With the exception of simultaneous contractions during manometry however, the incidence of abnormalities and in particular the correlation of pH events with chest pain are as common in patients with normal coronary angiograms as in controls with angina. The oesophagus may often be an unrecognised source of pain in both groups of patients.

Angina Pectoris↗
PubMed1997

The relationship between acid and bile reflux and symptoms in gastro-oesophageal reflux disease.

BACKGROUND: The role of bile in the genesis of oesophageal symptoms and disease is incompletely understood. A new method of ambulatory bile monitoring may help to define this role. AIMS: To establish the relationship between symptom events and acid and bile reflux episodes. PATIENTS: 59 consecutive patients presenting for further investigation of gastro-oesophageal reflux disease. METHODS: All patients underwent combined ambulatory pH and bile monitoring. For each patient, a symptom index (SI) was calculated in relation to both acid reflux and bile reflux episodes. RESULTS: Patients were divided into those without (group 1, n = 21) and those with (group 2, n = 38) acid reflux. A total of 394 symptoms were identified in 59 patients. In group 1, there were fewer symptom events per patient (mean 4.1) than group 2 (mean 8.1). Twenty three per cent of symptom events were associated with acid reflux in group 1 and 41% in group 2. Only 6% of symptom events in both groups were related to bile reflux. In group 1 both the acid and bile related SI score were low. In group 2 the bile related SI score was low, but the acid related SI score was high. CONCLUSIONS: Symptoms are much more often related to acid reflux than bile reflux. Bile reflux does not seem to be a major factor in producing oesophageal symptoms.

Adult↗
PubMed1997

Oesophageal motor responses to gastro-oesophageal reflux in healthy controls and reflux patients.

AIMS: To compare oesophageal motor responses to gastro-oesophageal reflux (GOR) in 16 healthy controls (group 1) and 25 reflux patients, 15 without (group 2) and 10 with (group 3) oesophagitis. METHODS: All subjects underwent 24 hour ambulatory oesophageal pH measurements (5 cm above the lower oesophageal sphincter (LOS)) combined with pressure monitoring (5, 10, and 15 cm above the LOS for oesophageal body motility and 27 cm above the LOS for voluntary swallow detection). Contraction patterns (peristaltic, simultaneous, isolated, mixed type, and non-transmitted swallows) and peristaltic contraction wave characteristics (amplitude, duration, and velocity) during GOR were compared in the three groups. RESULTS: The average number of motor activities per minute was significantly higher in group 1 (p < 0.05). In all groups, the most common motor contraction pattern was peristaltic. The percentage of peristaltic activity per subject was significantly higher in group 1 (p < 0.05). There were no significant differences in other contraction patterns among the three groups (p > 0.05). Of the peristaltic contraction wave characteristics there were no significant differences in any parameters (amplitude, duration, and velocity) among the three groups (p > 0.05). The average pH increment in response to motor activities was significantly higher in group 1 (p < 0.05). CONCLUSIONS: Motor responses to GOR were found to be predominantly primary peristaltic in all groups. During GOR, reflux patients have less frequent activity, a smaller proportion of activity is peristaltic, and the average pH increment in response to motor activities is reduced compared with controls.

Adult↗
PubMed1997

Bile in the oesophagus: clinical relevance and ambulatory detection.

BACKGROUND: Experimental work in animals has implicated a role for bile in the pathogenesis of several oesophageal mucosal diseases such as oesophagitis, Barrett's oesophagus and oesophageal adenocarcinoma. Recent descriptions of a high incidence of intestinal metaplasia at the gastro-oesophageal junction in patients without a classical 3-cm Barrett's columnar-lined segment, combined with a rising incidence in oesophageal and cardia adenocarcinoma, have stimulated interest in the causes of these conditions. METHODS AND RESULTS: Animal studies concerned with defining the role of the various gastroduodenal reflux constituents in oesophageal mucosal injury are summarized and evidence for bile in the pathogenesis of Barrett's oesophagus and oesophageal adenocarcinoma is reviewed. The results of various techniques for clinical measurement of oesophageal bile reflux, such as aspiration, scintigraphy and pH monitoring, are evaluated and the significance of recent studies employing ambulatory fibreoptic bilirubin monitoring is discussed. CONCLUSION: There seems little doubt that bile plays a significant role in oesophageal mucosal disease, in synergy with other constituents of reflux. Although ambulatory bilirubin monitoring is new, some intriguing findings have been reported and it is hoped that this technique will continue to shed light on the role of bile in the oesophagus.

Barrett Esophagus↗
PubMed1995

Crossover trial of partial shift working and a one in six rota system for house surgeons in two teaching hospitals.

The objective of this study was to compare an on call rota and partial shift working pattern for house surgeons in two hospitals. The study was conducted using a crossover trial of working both systems for 6 weeks each in two groups of newly appointed house surgeons. Assessment was by questionnaire to house surgeons, consultants, registrars, nursing staff and patients. The study took place at the departments of general surgery at Guy's and Lewisham Hospitals, London. A total of 12 house surgeons attached to four surgical firms and their consultants and registrars were the subject of our study. In addition the permanent nursing staff on designated general surgical wards and those patients of greater than 48 h stay on those wards on the day of assessment took part. Expectations of reduced fatigue levels using the partial shift system were not fulfilled. In contrast, this working pattern led to perceived disruption of the running of the surgical firms and demoralization of the house surgeons. Standards of patient care were, however, equally high using a rota or partial shift system. This comparison of a partial shift working pattern to an on call rota of similar average weekly hours demonstrated a marked preference for an on call rota from both medical and nursing staff although patients found both systems acceptable.

Cross-Over Studies↗
PubMed1994

Primary peristalsis is the major acid clearance mechanism in reflux patients.

This study examined the clearance of gastric acid from the oesophagus in ambulant patients with gastro-oesophageal reflux. Eighteen patients with proved reflux disease were studied, nine with (group 1) and nine without (group 2) endoscopic oesophagitis. Oesophageal pressure and pH were recorded over 24 hours. Pressures were measured by a probe with five sensors: a 5 cm long sensor in the lower oesophageal sphincter, three sensors in the body of the oesophagus, and one at the pharynx to detect swallowing. Oesophageal pH was monitored 5 cm above the lower oesophageal sphincter. Manometric activities were classified as either peristaltic or ineffective. The latter included simultaneous, non-transmitted, and low amplitude peristaltic contractions. A reflux episode was defined as starting when pH fell to less than 4 and ending when the pH rose to 5. When the rise to pH 5 took place in three or more discrete steps after motor responses to gastro-oesophageal reflux, the pH steps were labelled as initial change (I), middle changes (M), and last change (L). A total of 595 episodes of gastro-oesophageal reflux and 1626 associated motor events were analysed. Of these, 1331 (81.9%) were classed as primary peristaltic activity, 174 (10.7%) as primary ineffective activity, 46 (2.8%) as secondary peristaltic activity, and 75 (4.6%) as secondary ineffective activity. There were no significant differences in initial change (p > 0.05), middle changes (p > 0.05), and last change (p > 0.05) between group 1 and group 2. In all patients, the successive changes of pH in response to motor activity were significantly different (p = 0.0001) between initial, middle, and last changes. Last change was significantly higher when compared with initial (p=0.001) and middle changes (p<0.001). Primary oesophageal peristalsis was the most frequent motor response to gastro-oesophageal reflux. The last motor activity during reflux showed the greatest change in pH.

Adult↗
PubMed1994

Gastroesophageal reflux in patients with angiographically normal coronary arteries: an uncommon cause of exertional chest pain.

OBJECTIVES: To investigate the association between exertional chest pain and gastroesophageal reflux in patients with normal coronary angiograms and in controls by measuring oesophageal pH during treadmill exercise tests and to compare the results with routine ambulatory monitoring. DESIGN: Case control study. SETTING: Tertiary referral cardiac unit. PATIENTS: 50 consecutive patients with chest pain and completely normal coronary angiograms and 16 controls with coronary artery stenoses. MAIN OUTCOME MEASURES: Episodes of acid reflux and chest pain during treadmill exercise; a symptom index expressing the percentage of episodes of pain related to acid reflux during ambulatory monitoring. RESULTS: Four (8%) patients and two (12%) controls had reflux during treadmill exercise (NS). 32 (64%) and 16 (100%) reported chest pain, but only three (6%) and two (12%) had coincident reflux (NS). Reflux was as frequent before, during, and after treadmill exercise (five (8%) v six (9%) v two (3%)) in the 66 subjects; (NS). 19 (38%) patients and three (19%) controls had abnormal reflux on ambulatory monitoring (NS). Eight (16%) and three (19%) had a symptom index > 50%, but six and two of these reported pain without coincident reflux during treadmill exercise. CONCLUSION: There are many potential causes of chest pain in patients with angiographically normal coronary arteries. Although gastroesophageal reflux is commonly implicated and many patients have a high incidence of spontaneous reflux during ambulatory monitoring, it rarely occurs during exertion and the association with chest pain is poor.

Adult↗
PubMed1994

Long-term follow-up after total parathyroidectomy without parathyroid reimplantation in chronic renal failure.

Forty-three patients with secondary or autonomous hyperparathyroidism complicating chronic renal failure (CRF) underwent total parathyroidectomy (PTX) (follow-up 2-18 years, mean 8.7 years). Five were on conservative treatment for CRF, 35 on regular dialysis, and only three had a functioning allograft. At PTX, the most frequent findings were uncontrollable hypercalcaemia, musculo-skeletal pain, radiographic changes in the phalanges, and raised plasma parathyroid hormone (PTH) concentration. Pre-operatively, all patients were loaded with dihydrotachysterol or 1-alpha-OH cholecalciferol. Postoperatively, they were maintained on tapering doses of the same drugs and, briefly, oral calcium supplements. Five glands were identified and removed in two patients, four in 35 patients, three in three patients and only two in one patient. All had changes of hyperplasia and adenoma formation, except for one with a parathyroid carcinoma. Prompt symptomatic and radiographic improvement occurred, with normalization of plasma calcium and alkaline phosphatase. Postoperative PTH levels were available in 33 patients (23 by intact PTH assay): they were persistently high in 10/33 (2/23 intact); normal in seven (6 intact); low in 11 (3 intact), and undetectable in four (3 intact). Thus, PTX was incomplete in the majority of patients. Following transplantation, 3/20 (3/18 intact) patients still had detectable PTH. Only one patient developed symptomatic recurrent parathyroid disease requiring re-operation, and complications were few. Small dosages of vitamin D continue to be required, but not calcium supplementation, and no clinical effects of possible adynamic bone have been noted. At later renal transplantation in 27 patients, an easily treatable, uncomplicated hypocalcaemia was noted in 33%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1993

Significantly reduced acid detection at 10 centimeters compared to 5 centimeters above lower esophageal sphincter in patients with acid reflux.

Ambulatory pH monitoring of the esophagus is carried out by positioning a pH sensor 5 cm above the lower esophageal sphincter (LES). There are several techniques to locate the LES, and each method has a different margin of error. This work used dual pH sensors to monitor simultaneously at two different levels (5 and 10 cm above the LES) in order to establish the possible magnitude of error that could arise from inaccurate placement of a pH probe. Thirty-four patients with symptoms of gastroesophageal reflux (GER) were studied. They were grouped as 20 patients with pathological reflux (GER group) and 14 patients with physiological reflux, based on a reflux score derived by Johnson and DeMeester for distal esophageal pH monitoring. When the reflux scores were compared, the difference between the two monitoring levels was statistically significant in the GER group (p < 0.001) but not in the physiological reflux group (p = 0.09). In the GER group, the difference in the Johnson and DeMeester score accounted for a change in clinical diagnosis in nine of the 20 patients if the pH probe was placed at 10 cm above the upper margin of LES. Proximal reflux episodes (10 cm above LES) were preceded by distal reflux episodes (5 cm above LES) in 97% (878/901) of cases. Accurate probe placement is essential in the diagnosis of GER.

Esophagogastric Junction↗
PubMed1992

Acid perfusion and edrophonium provocation tests in patients with chest pain of undetermined etiology.

During the last five years, 672 patients were referred to our esophageal investigation unit; 110 patients (16.3%) of these presented with chest pain of undetermined etiology (CPUE) alone. Since the nature of this pain is intermittent and rarely present during the diagnostic study, acid perfusion and intravenous edrophonium tests were added as provocative tests after baseline esophageal manometry. Following completion of the motility studies, 24-hr pH study was performed to detect gastroesophageal reflux (GER). Twenty-nine patients (26.4%) had positive acid perfusion (APT) test whereas 26 patients (23.6%) had positive edrophonium test (ET). In the group of patients with positive acid perfusion test, 12/29 (41.3%) had GER, 8/29 (27.5%) had both motility disorder and GER, 2/29 (6.8%) had motility disorder, and 7/29 (24.1%) had normal esophageal motility and 24-hr pH studies. In the other group, 13/26 (50%) had motility disorder and 13/26 (50%) had both motility disorder and GER. There were no significant differences between the two tests as far as reproducibility of symptoms was concerned. We conclude that ATP and ET showed the esophageal origin of CPUE in half of our patients and therefore in a substantial percentage of patients the esophageal origin of chest pain will remain very difficult to prove.

Adult↗
PubMed1992

Management of diffuse esophageal spasm with balloon dilatation.

Of 1200 patients referred to the esophageal laboratory at Guy's Hospital for investigation of suspected esophageal motility disorders, 61 (5.1%) were diagnosed as diffuse esophageal spasm. Twenty of these patients whose symptoms were severe did not respond to conservative treatment and were treated by balloon dilatation. Results were good in 14 and poor in six patients, which included one esophageal perforation. Diffuse esophageal spasm was diagnosed where more than 30% nonperistaltic activity was demonstrated by manometry. Lower esophageal sphincter pressure and relaxation were normal in all cases except one. Gastroesophageal reflux was present in four of five poor responders who were examined by 24-h ambulatory pH monitoring, and in only one of 10 good responders. Three of the six patients in whom balloon dilatation was successful proceeded to full-length myotomy, with relief of symptoms in two. The indications for, and results of, balloon dilatation in this condition are discussed, and a new radiological sign is described.

Adult↗
PubMed1992

Alternative method of positioning the pH probe for oesophageal pH monitoring.

The most reliable method of positioning a pH probe for oesophageal pH monitoring is to use manometry to determine the upper margin of the lower oesophageal sphincter and to place the probe 5 cm above this point. Manometry is expensive, however, requires special equipment and training, and is not widely available. An alternative cheaper way of determining the site of the lower oesophageal sphincter has been evaluated. A fine bore nasogastric tube with a latex balloon at its tip was inserted transnasally into the stomach. The balloon was inflated with 10 ml of water and the tube withdrawn until resistance was met. The distance from the nose (in cm) was noted and compared with the upper margin of the lower oesophageal sphincter as determined by oesophageal manometry. The manometric distance agreed closely with the balloon distance minus 1 cm (bias 0.29 cm; 95% CI of bias, 0.03 to 0.55 cm; 2 SD, limits of agreement, 1.58 cm). We conclude that where oesophageal manometry is not available, balloon localisation is a suitably accurate way of identifying the lower oesophageal sphincter.

Adult↗
PubMed1991

Seroprevalence of antibodies against encephalomyocarditis virus in swine of Iowa.

A total of 2,614 swine from 104 herds located throughout Iowa were tested for antibodies against encephalomyocarditis virus (EMCV) by use of the microtitration serum neutralization test. The sample was composed of 587 sows and gilts and 2,027 finishing swine. A statistically significant (P less than 0.002) difference was observed between prevalence in sows and gilts (17.2%) and that in finishing swine (12.2%). Breeding swine maintained in total confinement (20.5%) had significantly (P = 0.04) higher prevalence than did breeders maintained in other types of housing (12.1%), whereas prevalence in finishing swine raised in total confinement (6.4%) was significantly (P = 0.02) lower that in finishers not raised in total confinement (13.6%). Association was not detected between prevalence and herd size or between prevalence and season of the year. Adjusting for test specificity and sensitivity, the true prevalence of EMCV infection in swine in Iowa was estimated to be 13.8% in breeding stock and 8.5% in finishing swine. On a herd basis, 89.4% (93/104) of the herds had one or more EMCV-positive swine.

Animals↗
PubMed1990

Prevalence of toxoplasmosis in swine from Iowa.

Of swine from 104 herds, 2,616 were tested for antibodies against Toxoplasma gondii, using an ELISA. Data were analyzed according to swine type, herd size, facility type, and season. The true prevalence of toxoplasmosis was estimated as 5.4% among finishing swine and 11.4% among sows and gilts. Herds with less than 100 breeding swine were significantly (P less than 0.05) more likely to be infected than were herds with greater than or equal to 100 breeding swine. The rate of seropositivity in breeding swine was approximately the same in infected herds, regardless of herd size. Herds with finishing swine maintained in total confinement were as likely to become infected as were herds maintained in other types of facilities, but infected herds with finishing swine maintained in confinement appeared to have a lower in-herd prevalence than did herds maintained in other types of facilities (P = 0.09). Seasonal effects were not observed, and prevalence remained relatively constant throughout the year.

Age Factors↗