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Biomedical subjects

G K Turnbull

Publications and source records attributed to G K Turnbull.

12 recordsLinked to original sources
PubMed1999

Spatial and temporal variations in the magnetic fields produced by human gastrointestinal activity.

Magnetoenterography (MENG) is a new, non-invasive technique that measures gastrointestinal magnetic signals near the body surface. This study was undertaken to evaluate the temporal and spatial characteristics of the magnetic signals generated by gastric and duodenal slow wave activity. The gastrointestinal magnetic fields of eight normal subjects were measured for 60 minutes in both the fasting and fed state using 36 magnetic sensors simultaneously. The results were displayed as a succession of maps over time showing the temporal evolution of the spatial distribution of the signal over the upper abdomen. In all subjects, slow wave activity of the stomach centred at 3.0 +/- 0.5 cycles min-1 in both the fasting and fed state was observed. The duodenal signal at 11.0 +/- 1.0 cycles min-1 was observed in four subjects. The spatial distribution of these two signals is distinctly different. The observed spatial and temporal variations are described in terms of a model used previously to explain the potentials observed in electrogastrography (EGG).

Adult↗
PubMed1999

The cortical topography of human anorectal musculature.

BACKGROUND & AIMS: The muscles of the anorectum are important in the volitional control of continence, yet virtually no information exists on their cortical representation in humans. METHODS: Topographic cortical mapping of both cerebral hemispheres was performed in 9 healthy subjects by applying suprathreshold transcranial magnetic stimulation to individual points on a scalp grid centered over the vertex and then recording the electromyographic responses from the external anal sphincter, rectum, and tibialis anterior muscles. RESULTS: Cortically evoked anal and rectal response latencies were similar (20.2 +/- 1.7 and 19.8 +/- 1.5 milliseconds, respectively) and were shorter than those from the anterior tibialis muscle (right, 29.7 +/- 2.3 milliseconds; left, 29.9 +/- 1.8 milliseconds; P < 0.0005). Cortical mapping showed that the anal responses were bilaterally represented on the superior motor cortex (Brodmann area 4) of both cerebral hemispheres; a similar topography was found for the rectal responses. By comparison, the tibialis responses showed predominantly contralateral medial motor cortex representation. Subtle but consistent differences in the degree of bilateral hemispheric representation were also apparent both between and within individuals for the anal responses and to a lesser extent for the rectal responses. CONCLUSIONS: The anorectal musculature has bilateral motor cortex representation with similar topography, but there is intersubject variation in the degree of symmetry.

Adult↗
PubMed1995

Quality of life in inflammatory bowel disease: the interaction of disease activity with psychosocial function.

OBJECTIVES: To evaluate the disease-specific and psychological factors that influence quality of life (QOL) in patients with inflammatory bowel disease (IBD) as measured by the recently developed IBD disease-specific QOL measure the Inflammatory Bowel Disease Questionnaire (IBDQ). METHODS: Twenty-two patients (eight males and 14 females) were studied, 16 with Crohn's disease and six with ulcerative colitis (mean age 32 yr). Patients' disease activity was measured with the Dutch Crohn's activity index and the St. Mark's colitis activity index, and QOL was measured by the IBDQ. All patients completed self-report questionnaires for psychological function, which included the Sickness Impact Profile (SIP), the Symptom Checklist-90-R (SCL), and the Self-Control Schedule (SCS). RESULTS: By combining the psychological measures and the disease activity into a single variable, this composite variable significantly predicted QOL (r = 0.53, p < 0.02), but disease activity alone did not predict overall QOL. Improved psychosocial functioning (Sickness Impact Profile) predicted greater overall QOL (IBDQ total: r = -0.49, p < 0.05) and better social functioning (r = -0.65, p < 0.01). Greater psychological distress (SCL) and disease activity predicted more systemic symptoms [SCL-Positive Symptom Total (PST): r = -0.48, p < 0.05; disease activity: r = -0.65, p < 0.03) and poorer emotional functioning (SCL-PST: r = minus] 0.75, p < 0.001; disease activity: r = -0.82, p < .03). Disease type, gender, age of onset, and psychological coping (SCS) were not predictive of disease-specific QOL, but coping (SCS) was significantly correlated with psychological distress (r = -0.58, p < 0.05 for the SCL-90-PST). CONCLUSION: This study confirms the importance of psychological functioning in determining QOL of IBD patients and must be considered jointly with disease activity.

Adaptation, Psychological↗
PubMed1992

Anal sphincter biofeedback relaxation treatment for women with intractable constipation symptoms.

Some constipated women have difficulty relaxing the striated muscles of the anal sphincters, sometimes called anismus. This study was developed to provide a biofeedback-based relaxation treatment to teach these patients to relax the "voluntary" anal sphincter muscle in order to assess whether this treatment would be effective in reducing symptomatology. Seven constipated patients who were unresponsive to a high-fiber diet and required persistent laxative dosing to achieve regular bowel frequency were studied. A dual-therapy approach, in which patients were taught to relax the anal sphincter muscles via biofeedback from a manometric anal sphincter probe, was used. Concurrently, patients were instructed in general biofeedback-relaxation techniques. All were treated as outpatients. Complete data were collected on five patients, one patient discontinued therapy, and one patient moved after treatment was completed. Stool frequency improved from a mean of 1.9 per week to a mean of 4.9 per week in six patients (P less than 0.05). In the five patients who completed the entire protocol, pain and bloating symptom levels were compared before and after treatment. Abdominal pain grade was reduced from 12.8 per week to a mean of 4.4 per week (P less than 0.05), and bloating was reduced from a mean of 14.3 per week to a mean of 6.0 per week (P less than 0.06). Follow-up of 2 to 4.5 years posttherapy showed continued improvement in bowel function and abdominal symptomatology. This treatment appears to be effective in improving stool frequency and in reducing the associated abdominal pain and bloating symptoms in constipated women with anismus.

Abdominal Pain↗
PubMed1989

Relationships between symptoms, menstrual cycle and orocaecal transit in normal and constipated women.

Because severe constipation is a disorder largely confined to young women, the possibility that menstrually related factors contribute to disturbed gastrointestinal motor function has been raised. It has also been reported that normal menstruating women show changes in upper gut transit between the follicular and luteal phases of the menstrual cycle and that patients with constipation show prolonged transit. We therefore studied relationships between symptom severity and orocaecal transit during the menstrual cycle in a group of 14 constipated women and a series of control groups comprising seven normal menstruating women, five postmenopausal women, and eight normal men, to determine whether phases of the menstrual cycle were associated with alteration in symptoms or transit. A regular menstrual cycle was reported by 13 of the 14 patients (range 26-30 days) and by all the menstruating female volunteers. Seven patients noted variation in constipation during the menstrual cycle, in all cases this comprised an improvement in symptoms just before or during menstruation. No consistent relationship between symptom severity and follicular or luteal phase was noted. Repeated orocaecal transit measurements in the four study groups showed no consistent differences (greater than 0.05) between groups or during the menstrual cycle (mean change weeks 1-4, -10 +/- 20 min). These findings are inconsistent with the hypothesis of a progesterone related effect upon orocaecal transit in either normal or constipated women.

Adult↗
PubMed1988

Evacuation proctography: an investigation of rectal expulsion in 20 subjects without defecatory disturbance.

Evacuation proctography is a dynamic investigation of rectal expulsion that records the voluntary evacuation of thick barium paste on videotape. Evacuation is a passive phenomenon in a defined zone of the rectum, associated with pelvic floor descent of 3 cm from a resting position of the anorectal junction less than 2 cm above the plane of the ischial tuberosities. The anal canal does not open immediately; it takes about 4.5 sec to open to a maximum diameter of 1.5 cm, with rectal emptying in 11 sec. Anterior rectoceles commonly invert over the anal canal as the rectum collapses in at the end of evacuation.

Defecation↗
PubMed1988

Radiologic studies of rectal evacuation in adults with idiopathic constipation.

A consecutive series of 58 patients with idiopathic constipation and 20 control subjects were studied by evacuation proctography and measurements were made of changes during rectal expulsion. A wide range was found in the control group. The anorectal angle, pelvic floor descent, and the presence or size of an anterior rectocele did not discriminate between the control and patient groups. Internal intussusception was rare. Among constipated patients, the only significant differences from normal were in the time taken to expel barium and the amount of barium remaining in the distal rectum. The majority of control subjects (15 of 20) evacuated most of the barium within 20 seconds whereas 45 of 58 constipated patients took a longer time. Using the area of barium on a lateral view of the rectum as a measure, 19 of 20 control subjects evacuated at least 60 percent of the barium from the distal 4 cm of the rectum compared with only 25 of 58 patients. A varying degree of defecatory impairment was thus established among many patients with constipation. The patients were subdivided into those with a normal or abnormal whole gut transit rate as an indication of colonic function, and those who did or did not need to digitally evacuate the rectum as a clinical manifestation of an anorectal disorder. No obvious differences were found between these subgroups using the parameters measured.

Adult↗
PubMed1987

The aminopyrine breath test, an inadequate early indicator of methotrexate-induced liver disease in patients with psoriasis.

The aminopyrine breath test has been shown to be a sensitive noninvasive indicator of liver cell dysfunction. In a search for a noninvasive method of monitoring the effects of methotrexate therapy, we have investigated the use of the aminopyrine breath test in patients receiving methotrexate for the treatment of severe psoriasis. The [14C]-aminopyrine breath test was performed in 20 normal control subjects, 32 patients with psoriasis receiving methotrexate therapy, and 8 patients with histologically confirmed cirrhosis of differing etiology. Eighteen patients on methotrexate had liver biopsies classified as grade I changes, 6 patients as grade II, and 8 patients as grade III. The normal value for the breath test was 11.0 +/- 1.6% (mean +/- 1 SD). The mean [14C]-CO2 excretion (8.3 +/- 4.4%) of the 8 patients with grade III liver disease was significantly different from the control subjects (p less than 0.02), and those with grade I liver changes (p less than 0.04). The aminopyrine breath test was only able to detect the later severe stages of methotrexate hepatotoxicity, grade III, when fibrosis occurs, before established cirrhosis was present. Our data suggests that the aminopyrine breath test is not a sensitive indicator for the detection of early methotrexate-induced hepatotoxicity, (stages I and II), but will detect the precirrhotic stage III change. Consequently, we recommend that a liver biopsy should be performed annually in all psoriatic patients receiving methotrexate, to detect histological damage, especially when the aminopyrine breath test score falls below the 95% confidence limits of normal.

Aminopyrine↗
PubMed1986

Failure of rectal expulsion as a cause of constipation: why fibre and laxatives sometimes fail.

High-fibre diet and laxatives are not always successful in the treatment of severe constipation. In a group of thirteen women with intractable constipation three experimental models of rectal evacuation showed that all had a disorder of defaecation. None could expel 120 ml barium paste as fast or as completely as could ten normal women; six could expel hardly any barium. Only three of the thirteen could expel a balloon containing 50 ml water from the rectum, whereas all of six normal subjects could do so easily. Four of the patients with repeated straining efforts could expel no more than 10% of a 500 ml saline enema, whereas six normal subjects rapidly passed 40-80%. It is postulated that dietary and drug treatment designed to soften and increase the bulk of the stools fails to help some patients because they find it difficult to expel even semi-solid or liquid stool. Electromyography showed that these patients tend to contract rather than relax the striated muscle of the pelvic floor on attempted defaecation. Their failure to defaecate is due to incoordination of the pelvic floor rather than an abnormality of the stool or a disorder of the colon.

Acute Disease↗