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Biomedical subjects

A Pryde

Publications and source records attributed to A Pryde.

33 records · Page 2Linked to original sources
PubMed1989

Examination of the envelope glycoprotein of yellow fever vaccine viruses with monoclonal antibodies.

Two panels of envelope glycoprotein reactive monoclonal antibodies (mAbs) were prepared against yellow fever (YF) 17D vaccine viruses. Five mAbs were prepared against the World Health Organization 17D-204 avian leukosis virus-free secondary seed virus and eight mAbs against 17DD vaccine manufactured in Brazil. The majority of these mAbs were type-specific and displayed differing reactions in neutralization tests. One, B14, would only neutralize YF vaccine virus grown in invertebrate cells. Others would differentiate 17D-204 and 17DD vaccines, from different manufacturers, in neutralization tests when the viruses were grown in vertebrate cells. The data indicate that heterogeneity exists between the epitopes that elicit neutralizing antibody on YF vaccine from different manufacturers.

Animals↗
PubMed1989

Oesophageal manometry during eating in the investigation of patients with chest pain or dysphagia.

Dysphagia is a frequent cause of referral for oesophageal manometry although the motor response to eating is not routinely studied. We examined symptoms and oesophageal motor patterns in response to eating bread in 30 patients with either gastro-oesophageal reflux (n = 20), or normal oesophageal function tests (n = 10). No patient experienced symptoms while swallowing water but one complained of heartburn and one developed symptomatic oesophageal 'spasm' during eating. In eight further patients, pain or dysphagia which occurred with swallowing bread was associated with aperistalsis. Comparing asymptomatic and symptomatic periods, there was a slight increase in mean swallow frequency from 7.5 (0.79) (SEM) to 9.0 (1.17) swallows per minute (NS; n = 10). The mean number of aperistalsis swallows increased from 4.5 (0.96) per minute to 6.2 (1.30) (p less than 0.01; n = 10). Aperistalsis during symptoms was mainly caused by non-conducted swallows rather than synchronous contractions (mean 5.8 (1.45) per minute compared with 1.2 (0.44]. Aperistalsis can be produced by rapid swallowing in the normal oesophagus through 'deglutitive inhibition'. These results suggest that some patients experience dysphagia associated with aperistalsis perhaps as a response to increased frequency of swallowing. Functional abnormalities of this nature will not be detected by conventional oesophageal manometry.

Adult↗
PubMed1989

Gastroesophageal reflux and posterior laryngitis.

Esophageal acid exposure was assessed by 23-hour ambulatory pH monitoring and compared with a biopsy of the posterior larynx and proximal esophagus in 97 patients with hoarseness, burning pharyngeal discomfort, or globus sensation. Patient results were compared with normal acid exposure times obtained in 54 control subjects. In 24 patients there were laryngeal abnormalities but both esophageal biopsy results and acid exposure times were normal. Laryngeal disease was found in association with prolonged acid exposure time or esophagitis in only 17 of the 97 patients (17.5%) studied. Recent reports appear to have overestimated the importance of acid reflux as a cause of posterior laryngitis.

Adult↗
PubMed1988

Effect of alterations in test meal composition on episodic transpyloric fluid movement in humans.

Using real-time ultrasonic imaging we have observed the effect of four different liquid test meals on transpyloric fluid movement and related gastroduodenal motor activity in 10 normal subjects. The mean interval between antral contractions (cycle times), and the frequency of occurrence of related proximal duodenal contractions were similar with all four meals (F = 0.3, for both). Forward (gastroduodenal) flow through the pylorus was observed in 95% of cycles and occurred as up to four brief episodes per cycle, each lasting 2-3 sec. The duration of these episodes with pH 2.8 and pH 7.0 meals was longer than with protein and glucose meals (P less than 0.05). There were, however, fewer episodes of forward flow in each cycle with the pH 2.8 and pH 7.0 meals with the protein and glucose meals (P less than 0.05). Retrograde (duodenogastric) flow was observed in 56% of cycles and occurred, on average, as less than one brief episode lasting about 2 sec each cycle. The pattern of retrograde flow was similar with all meals. Gastric emptying and duodenogastric fluid movement both occur in intermittent brief episodes lasting a few seconds only. Changes in the nature of the test meal cause subtle alterations in the basic pattern of transpyloric fluid movement, presumably reflecting the influence of the meal on control mechanisms governing gastric emptying.

Adult↗
PubMed1988

Comparison of intravenous edrophonium and oesophageal acid perfusion during oesophageal manometry in patients with non-cardiac chest pain.

Sixty consecutive patients referred for evaluation of non-cardiac chest pain had oesophageal manometry. Motility was assessed basally, after edrophonium 80 micrograms/kg iv and during oesophageal perfusion with 0.1 N HCl at 6 and 14 ml/min for eight and seven minutes respectively. A positive response, defined as symptom reproduction with or without abnormal motility, was present in 21 patients (35%) after acid perfusion and 12 (20%) after edrophonium. Eleven of the 12 patients responding to edrophonium also responded to acid perfusion, including most of the patients with primary motility disorders. Significantly greater increases in peristaltic duration, but not amplitude, were recorded after edrophonium (p less than 0.01) and acid perfusion (p less than 0.05) in positive responders, compared with non-responders. Results indicate that acid perfusion during oesophageal manometry may be a more useful stress test than edrophonium and that the mechanism of symptom production may be similar.

Adolescent↗
PubMed1987

Effect of omeprazole on lower oesophageal function in normal subjects.

In a double-blind crossover study, lower oesophageal sphincter pressure (LOSP) and distal oesophageal motility were studied in eight healthy volunteers following a single intravenous dose of omeprazole or placebo. Lower oesophageal sphincter pressure was determined before and at intervals up to 120 min after intravenous administration of 40 mg omeprazole or placebo. No effects on LOSP or distal oesophageal motility were observed.

Adult↗
PubMed1987

Globus sensation is not due to gastro-oesophageal reflux.

Oesophageal manometry and prolonged ambulatory pH monitoring were performed in 47 patients with the globus sensation, 48 control subjects and 28 patients with documented oesophagitis. Globus patients also underwent video-recorded barium examination and rigid endoscopy. Manometry was normal in 38 of the globus group (94%). The mean percentage time below pH 4 was 4.16 in controls, 5.11 in globus patients (NS) and 18.54 in oesophagitis patients (P less than 0.0005). Oesophageal acid exposure did not correlate with sex, smoking or heartburn and correlated with age only in oesophagitis patients (P less than 0.001). Biopsy showed mild laryngitis in 2 globus patients and distal oesophagitis in 6 (13%). Abnormal oesophageal acid exposure and distal oesophageal dysmotility are not aetiological factors in the majority of patients with globus pharyngis.

Adult↗
PubMed1987

Daytime gastro-oesophageal reflux is important in oesophagitis.

Fifty two patients were studied to investigate the patterns of gastro-oesophageal reflux during ambulatory pH monitoring and the relationship of reflux to presence and severity of oesophagitis. Twenty nine had evidence of oesophagitis which was graded according to severity. Acid exposure (pH less than 4) was calculated in each case for the total study period, the recumbent and upright periods, and the three hour period after the evening meal. Exposure in the upright period correlated closet (r=0.92: p less than 0.001) with that during the total period. Recumbent exposure correlated with both upright and postprandial exposure (p less than 0.001). Acid exposure during all four periods correlated significantly with the severity of oesophagitis, but postprandial acid exposure correlated best and recumbent acid exposure least well. Although acid clearance in the total, recumbent and upright periods correlated with oesophagitis, postprandial clearance showed the closest relationship. Thus the magnitude of daytime reflux, especially postprandial reflux and acid clearance, is more closely related than nocturnal reflux to oesophagitis. The results do not support the contention that night time reflux is inherently more injurious than daytime reflux to the oesophageal mucosa.

Eating↗
PubMed1987

Transpyloric fluid movement and antroduodenal motility in patients with gastro-oesophageal reflux.

The pattern of transpyloric fluid movement and associated antroduodenal motility was compared in patients with gastro-oesophageal reflux (GOR) and healthy controls using real time ultrasonic imaging. A similar number of cyclical periods of antroduodenal motor activity (GOR 94 and control 91) was studied in each group. Mean antral cycle times and the frequency of occurrence of related proximal duodenal contractions (antroduodenal coordination) were similar. Transpyloric fluid movement occurred as a number of discrete episodes in each cycle. Gastroduodenal flow was more frequent in the GOR group (mean 2.7 +/- 0.4 episodes per cycle) than in controls (mean 1.7 +/- 0.3). The mean duration of these episodes in both groups was similar at around 2.5 seconds. Duodenogastric flow (reflux) was observed in many cycles (GOR 63%; controls 54%), but there was no difference in the mean number of episodes per cycle (GOR 0.79; control 0.74) or their mean duration (two seconds for both). Transpyloric fluid flow only occurs when a pressure gradient is created across the open pylorus. These observations indicate that in GOR the gastroduodenal pressure gradient is positive more frequently than in normal controls. Gastroduodenal liquid flow but not duodenogastric reflux differs in GOR patients and controls.

Body Fluids↗
PubMed1985

Coordinated motor activity of the human gastroduodenal region.

Using real-time ultrasonic imaging, and a test meal of 500 ml of dilute orange juice, we have studied the temporal relationships among contractions of the terminal antrum, pylorus, and proximal duodenum of 22 normal subjects. A total of 259 cyclical periods of motor activity were observed. Individual mean gastroduodenal cycle times ranged from 17.9 to 29.6 seconds (2.0-3.3 cycles/min). Terminal antral contractions (TACs) were observed in 98% of cycles and pyloric closure invariably occurred at the midpoint of these contractions. The pylorus then opened as the terminal antrum relaxed and remained open until the next TAC. Only 67% of TACs were associated with contractions of the proximal duodenum (DC), but 94% of these occurred about 1 sec (range 1 sec before to 2 sec after) after pyloric closure. Only 6% of DCs were ectopic, in that their occurrence was apparently uncoordinated with the TACs. Our observations demonstrate that after ingestion of a test meal, the human terminal antrum, pylorus, and proximal duodenum usually contract in a sequential coordinated manner, presumably under the control of the gastric slow wave. No evidence of independent pyloric closure was obtained.

Adult↗
PubMed1984

Relationships of human antroduodenal motility and transpyloric fluid movement: non-invasive observations with real-time ultrasound.

To study the relationships between gastric antral and proximal duodenal motor activity, and the movement of liquid across the pylorus, 10 healthy volunteers were given a test meal of dilute orange juice and bran, and events at the gastric outlet monitored by real-time ultrasound. A total of 116 complete gastric peristaltic cycles were observed and in 86% of these, associated proximal duodenal contractions were seen. Transpyloric fluid movement, as reflected by the movement of the bran particles, occurred as brief episodes during the time when the pylorus was open. Distal flow, in episodes lasting 2-4 seconds, was seen to occur in 81% of the 116 complete cycles and 75% of these episodes occurred just after the relaxation of the terminal antrum, pylorus, and proximal duodenum. The remainder occurred shortly before the terminal antral contraction. Retrograde flow, in episodes of up to 5 seconds, occurred in 78% of observed cycles with the majority occurring immediately before contraction of the terminal antrum. Our findings indicate that transpyloric fluid movement occurs in brief episodes lasting a few seconds only and that retrograde flow across the pylorus occurs in normal subjects. This pattern of fluid movement can bear no direct relationship to a steadily advancing antral peristaltic contraction, nor be wholly attributable to constant intragastric pressure.

Adult↗
PubMed1979

Serum IgA in the neonate. Molecular size, concentration and effect of breast feeding.

IgA concentrations in the serum of 48 six-day-old neonates (23 exclusively artificially fed, 25 exclusively breast fed) were measured using a double antibody radioimmunoassay. In 24 of the neonates, umbilical cord blood was also studied. Gel filtration was used to estimate the molecular size of IgA present in cord and neonatal serum. The arithmetic mean concentration of IgA (+/- S.E.M.) found in the 48 neonates was 2.6 +/- 1.45 mg/l. No significant difference was detected between the breast fed and artificially fed neonates. Only 7S IgA was detected in cord blood and in neonatal serum. Six days of exclusive breast feeding therefore has no influence on total serum IgA levels on the sixth day of neonatal life nor does it result in detectable circulating 11S IgA at that time.

Age Factors↗
PubMed1976

Immunoglobulin synthesis in the "resting" breast.

Nulliparous women have a greater risk of developing breast cancer than women who have borne children, but so far no functional differences in breast tissue have been reported between parous women and nulliparae. Macroscopically and histologically normal breast tissue was obtained from 74 women of reproductive age during biopsy of benign breast lesions and was examined for the presence of plasma cells by immunfluorescence. Immunoglobulin synthesis was detected by an in-vitro culture technique. Synthesis of IgA was detected in 81% of specimans of IgG in 45%, and of IgM in 3%. IgA synthesis much more intense than IgG or IgM synthesis. Plasma cells containing IgA were seen in 71% of the specimens examined, and 88% of specimens had deposits of IgA in the ductules. The findings were not significantly incluenced by the nature of the condition necessitating biopsy or by oral contraception. Nulliparous women showed no cyclical changes, but among parous women IgA synthesis was more intense during luteal phase of the menstrual cycle. This suggests that after the first pregnancy the breast is more sensitive to progesterone.

Adolescent↗
PubMed1975

The analysis of paraquat in urine by high-speed liquid chromatography.

The paraquat content of urine can be directly determined by high-speed liquid chromatography using ultraviolet spectrophotometric detection. The method separates paraquat (and diquat) from the ultraviolet-absorbing components of urine and no extraction or pre-treatment of the sample is required prior to analysis. Concentrations down to 100 mug/1 of paraquat in urine were determined. Quantitative results are in good agreement with those obtained by a colorimetric method. Diquat does not interfere with the analysis of paraquat, and it would also be possible to analyse diquat in paraquat-containing urine.

Absorption↗