Biomedical subjects

S Fullerton

Publications and source records attributed to S Fullerton.

35 records · Page 2Linked to original sources

PubMed1997

Evidence for two distinct perceptual alterations in irritable bowel syndrome.

BACKGROUND: Visceral hyperalgesia has been implicated as a factor contributing to symptom generation in irritable bowel syndrome (IBS). However, previous studies using intestinal balloon distension have used psychophysical procedures which do not provide adequate and unbiased measures of visceral sensitivity. METHODS: Three psychophysical tasks were examined in 45 patients with IBS (positive Rome criteria) and 14 controls using rectal balloon distension with a computerised distension device. Discomfort threshold and tolerance were assessed during an ascending series of phasic pressure stimuli and during an interactive threshold tracking procedure. In addition, stimulus response functions were generated from intensity and unpleasantness ratings of the rectal distensions. RESULTS: Discomfort threshold and tolerance for the ascending stimuli were significantly lower for the patients with IBS compared with the controls. In contrast, discomfort thresholds during the tracking procedure and stimulus response curves for the ascending series were not different between the groups. A factor analysis of the psychophysical data was consistent with the presence of two distinct and unrelated perceptual alterations related to rectal distension: hypervigilance for visceral stimuli, manifested as lowered response criteria for using the descriptor "discomfort"; and rectal hypersensitivity, manifested as a lower discomfort threshold and left shift of the stimulus response curves. CONCLUSIONS: Patients with IBS as a group have a greater propensity to label visceral sensations negatively and show a lower tolerance for rectal balloon distension. A subgroup of patients also have baseline rectal hypersensitivity, assessed by unbiased measures of discomfort threshold and stimulus intensity judgements.

Adult↗

PubMed1996

Effects of the corticotropin-releasing factor (CRF) on rectal afferent nerves in humans.

Corticotropin-releasing factor (CRF) released in the gastrointestinal mucosa from immune cells or enterochromaffin cells may play a role in the modulation of rectal afferent function. In the current study we evaluated the effects of peripherally administered CRF on afferent mechanisms in the human rectum. We used rectal balloon distention in seven healthy volunteers to evaluate the effect of CRF (1 microgram/kg) on visceral afferents originating in the rectum which are involved in the following functions: thresholds and intensity of conscious perception, receptive relaxation, reflex inhibition of internal anal sphincter and a viscerosomatic reflex. Rectal mechanoreceptors were stimulated either by distending the rectum using a volume ramp (40 and 400 mL/min), or by intermittent phasic distention. CRF decreased the thresholds and increased the intensity for the sensation of discomfort in response to both ramp and phasic distention. During slow ramp distention, CRF also lowered the stool threshold. CRF increased rectal compliance during slow ramp distention without affecting the rate of receptive relaxation or the inflection point of the compliance curve. CRF had no effect on viscerosomatic referral patterns, or on the rectoanal inhibitory reflex. These findings are consistent with a dual effect of CRF on afferent pathways mediating perception of aversive rectal sensations, and on rectal smooth muscle.

Adult↗

PubMed1996

Health-related quality of life, patient outcome, and managed care: the road ahead.

The delivery of healthcare in the industrialized world is currently undergoing fundamental change due to a number of factors. These include market forces driving institutions to contain and reduce cost; the rapid emergence of new treatments; the recognition of unexplained regional variations in the delivery of care; and patients' increasing sophistication and involvement as consumers of healthcare resources. As a result, the practice of medicine is entering a new era of scrutiny. Demonstrating a treatment's safety and efficacy is no longer sufficient justification for its use. There is a need to evaluate the appropriateness of medical care based on both cost and patient outcomes measures, including health-related Quality of Life (HRQOL). This type of research is in the interests of healthcare provider organizations, physicians, and patients alike. Outcomes research in the GI diseases is expanding rapidly due to the potential for cost savings and increased quality of care. It is important that gastroenterologists become trained and take part in the design, conduct, and analysis of outcomes studies to maximize these gains.

Gastrointestinal Diseases↗

PubMed1996

Symptom duration in patients with irritable bowel syndrome.

OBJECTIVES: The etiology and natural history of irritable bowel syndrome (IBS) is poorly understood. We compared rectal sensory thresholds and compliance, SCL-90 scores, and follow-up questionnaires among normal controls, patients with longstanding ( > 5 y) disease (L-IBS), and patients with recent onset ( > 2 y) disease (R-IBS). The onset of symptoms in R-IBS was related to specific events such as infection (n = 10), surgery (n = 5), and stress (n = 4), but no specific event could be identified in six patients. METHODS: A diagnosis of IBS was made using Manning criteria ( > or = 3) and clinical grounds. Psychological data were obtained by psychometrics (SCL-90) scores. Rectal wall compliance and thresholds for the sensation of stool and discomfort were evaluated using the electronic barostat. RESULTS: The mean thresholds for phasic and ramp distention were similar for R-IBS and L-IBS groups for the perception of stool and discomfort. When compared with normals, the mean stool thresholds for phasic distention were significantly lower for L-IBS and R-IBS groups. SCL-90 scores were significantly increased in L-IBS in the mean phobia score (45 R-IBS vs 61 L-IBS), anxiety score (49 R-IBS vs 63 L-IBS), paranoia score (44 R-IBS vs 60 L-IBS), and hostility score (47 R-IBS vs 61 L-IBS) (all p < 0.05). On follow-up questionnaire, 60% of R-IBS versus 46% of L-IBS patients indicated that their symptoms had improved (p < 0.05). R-IBS patients also experienced fewer episodes of abdominal pain per week at follow-up than L-IBS patients (3.9 +/- 1.0 vs 8.5 +/- 1.7, respectively) (p < 0.05). CONCLUSIONS: Our findings suggest that IBS patients with short symptom duration and fewer psychological symptoms have a better prognosis than patients with a long history of IBS and associated psychological distress, although long term prospective studies are needed.

Adolescent↗

PubMed1995

Health marketing information: an assessment of past and future utilization patterns.

A sample of 108 members of the Academy of Health Services Marketing provided bibliographic citations of 629 sources of information which have been important to them in their jobs. The results indicate that the propensity to rely upon a source is dependent upon the topic of the information sought. The sources under scrutiny were consultants, books, journals, magazines, seminars, conferences, video tapes, and audio tapes. The topics considered included the variables of the marketing mix as well as market planning and marketing research. The discussion provides insight about where seekers of health care marketing knowledge go for specific kinds of information. It also suggests types of media that information-providers should consider for dissemination of their material.

Advertising↗

PubMed1993

Pathophysiology and treatment of clinically resistant cytomegalovirus retinitis.

PURPOSE: To determine the incidence, pathophysiology, clinical outcome, and survival in patients with clinically resistant retinitis. METHODS: Cytomegalovirus (CMV) retinitis was prospectively studied in 100 patients with acquired immune deficiency syndrome (AIDS). In 11 of these patients, clinically resistant retinitis developed, defined as new activity or progression, despite at least 8 consecutive weeks of induction doses of either foscarnet or ganciclovir. Fundus photography, pharmacokinetics, CMV cultures and sensitivities, and survival analyses were studied. The therapeutic interventions attempted after clinically resistant retinitis was identified included continuing a high dose (induction level) of the same antiviral drug, changing the antiviral drug, and combining antiviral therapy with foscarnet and ganciclovir. RESULTS: Clinically resistant retinitis occurred in 11 (11%) of 100 patients with CMV retinitis and appeared to be a manifestation of acquired CMV antiviral drug resistance. Drug metabolism and pharmacokinetics in these patients were normal. The use of combination therapy with foscarnet and ganciclovir was effective in halting the progression of retinitis in three (75%) of four patients (6 of 7 eyes able to be evaluated) receiving combination therapy. CONCLUSION: Clinically resistant retinitis is a manifestation of infection by CMV that has acquired drug resistance. In these patients, combination antiviral drug treatment should be considered. It is likely that clinically resistant retinitis will become more frequent as patients with CMV retinitis and AIDS survive longer.

AIDS-Related Opportunistic Infections↗

PubMed1990