Research in consultation-liaison psychiatry: the Toronto General Hospital experience

Research that has developed in association with the consultation-liaison service at the Toronto General Hospital is reviewed in this paper. The value of systematic investigation in the consultation-liaison setting is addressed. Such approaches may be necessary to establish consultation-liaison psychiatry as a theoretical discipline which can advance knowledge in addition to enhancing patient care.     

Transfers to psychiatry through the consultation-liaison psychiatry service: 11 years of experience

Background  

There are only a few reports on issues related to patient transfer from medical and surgical departments to the psychiatric ward by the consultation-liaison psychiatry service, although it is a common practice. Here, we present a study assessing the factors that influence such transfers.     

Biomechanics of the gastrointestinal tract

Abstract As the function of the gastrointestinal tract is to a large degree mechanical, it has become increasingly popular to acquire distensibility data in motility research based on various parameters. Hence it is important to know on which geometrical and mechanical assumptions the various parameters are based. Currently, compliance and tone derived from pressure-volume curves are by far the most often used parameters. However, pressure-volume relations obtained in tubular organs must be carefully interpreted as they provide no direct measure of luminal cross-sectional area and other variables useful in plane stress and strain analysis. Thus, erroneous conclusions concerning tissue distensibility may be deduced. Other parameters, such as wall tension, stress and strain, give more useful information about mechanical behaviour. Distensibility data procure significance in fluid mechanics and in the study of tone, peristaltic reflexes, and mechanoreceptor kinematics. Such data are needed for the determination of the interaction between stimulus, electrical responses in neurons and the mechanical behaviour of the gut. Furthermore, from a clinical perspective, investigation of visco-elastic properties is important because GI diseases are associated with growth and remodelling. For example, prestenotic dilatation, increased collagen synthesis, dysmotility and altered distensibility are common features of obstructive diseases. The purpose of this review is to discuss the physiological and clinical importance of acquiring biomechanical data, distensibility parameters and interpretation of these results and their associated errors. We will also discuss some aspects of the relationship between morphology, growth and biomechanics. Finally, we will outline a number of techniques to study the mechanical properties of the GI tract.     

Sensory transmission in the gastrointestinal tract

Abstract The gastrointestinal (GI) tract must balance ostensibly opposite functions. On the one hand, it must undertake the process of digestion and absorption of nutrients. At the same time, the GI tract must protect itself from potential harmful antigenic and pathogenic material. Central to these processes is the ability to ‘sense’ the mechanical and chemical environment in the gut wall and lumen in order to orchestrate the appropriate response that facilitates nutrient assimilation or the rapid expulsion through diarrhoea and/or vomiting. In this respect, the GI tract is richly endowed with sensory elements that monitor the gut environment. Enteric neurones provide one source of such sensory innervation and are responsible for the ability of the decentralized gut to perform complex reflex functions. Extrinsic afferents not only contribute to this reflex control, but also contribute to homeostatic mechanisms and can give rise to sensations, under certain circumstances. The enteric and extrinsic sensory mechanisms share a number of common features but also some remarkably different properties. The purpose of this review is to summarize current views on sensory processing within both the enteric and extrinsic innervation and to specifically address the pharmacology of nociceptive extrinsic sensory pathways.     

Sensory transmission in the gastrointestinal tract

Abstract  The gastrointestinal (GI) tract must balance ostensibly opposite functions. On the one hand, it must undertake the process of digestion and absorption of nutrients. At the same time, the GI tract must protect itself from potential harmful antigenic and pathogenic material. Central to these processes is the ability to 'sense' the mechanical and chemical environment in the gut wall and lumen in order to orchestrate the appropriate response that facilitates nutrient assimilation or the rapid expulsion through diarrhoea and/or vomiting. In this respect, the GI tract is richly endowed with sensory elements that monitor the gut environment. Enteric neurones provide one source of such sensory innervation and are responsible for the ability of the decentralized gut to perform complex reflex functions. Extrinsic afferents not only contribute to this reflex control, but also contribute to homeostatic mechanisms and can give rise to sensations, under certain circumstances. The enteric and extrinsic sensory mechanisms share a number of common features but also some remarkably different properties. The purpose of this review is to summarize current views on sensory processing within both the enteric and extrinsic innervation and to specifically address the pharmacology of nociceptive extrinsic sensory pathways.     

Sensing of glucose in the gastrointestinal tract

In general, nutrient sensing mechanisms in the intestine are not well understood. Potential sensors include the terminals of extrinsic afferent nerves, enteric nerves, endocrine cells and other epithelial cells including enterocytes and immune cells. This short review will concentrate on the neural pathways that are activated by the presence of glucose in the intestinal lumen and the role of a specialized endocrine cell, the enterochromaffin cell in glucose-sensing and the subsequent activation of extrinsic neural pathways.     

Innervation of the gastrointestinal tract: patterns of aging

The gastrointestinal (GI) tract is innervated by intrinsic enteric neurons and by extrinsic projections, including sympathetic and parasympathetic efferents as well as visceral afferents, all of which are compromised by age to different degrees. In the present review, we summarize and illustrate key structural changes in the aging innervation of the gut, and suggest a provisional list of the general patterns of aging of the GI innervation. For example, age-related neuronal losses occur in both the myenteric plexus and submucosal plexus of the intestines. These losses start in adulthood, increase over the rest of the life span, and are specific to cholinergic neurons. Parallel losses of enteric glia also occur. The extent of neuronal and glial loss varies along an oral-to-anal gradient, with the more distal GI tract being more severely affected. Additionally, with aging, dystrophic axonal swellings and markedly dilated varicosities progressively accumulate in the sympathetic, vagal, dorsal root, and enteric nitrergic innervation of the gut. These dramatic and consistent patterns of neuropathy that characterize the aging autonomic nervous system of the GI tract are candidate mechanisms for some of the age-related declines in function evidenced in the elderly.     

Sleep and the gastrointestinal tract

In this review, an integration of GI functioning is attempted with regard to its relationship to sleep, how this interaction may lead to complaints of sleep disorders, and the pathogenesis of some GI disorders. Data are presented to support the notion that sleep-related GER is an important factor not only in the development of esophagitis but also in the respiratory complications of GER. Although sensory functioning is altered markedly during sleep with regard to most standard sensory functions (eg, auditory), there seems to be an enhancement of some visceral sensation during sleep that seems to protect the tracheobronchial tree from aspiration of gastric contents reflux during sleep. Patients who have functional bowel disorders reveal an increase in sleep complaints compared with normal volunteers. The actual mechanisms of these disturbances remain somewhat obscure and studies do not demonstrate any consistent abnormalities in sleep patterns of these patients. Some studies show that autonomic functioning during sleep, particularly REM sleep, can distinguish patients who have IBS. Thus, the continued study of sleep and GI functioning promises to create a new dimension in the understanding of the pathophysiology of a variety of GI disorders.     

Galanin receptors in the rat gastrointestinal tract

Galanin functions are mediated by three distinct G-protein-coupled receptors, galanin receptor 1 (GalR1), GalR2 and GalR3, which activate different intracellular signaling pathways. Here, we quantified mRNA levels of GalR1, GalR2 and GalR3 in the gastrointestinal tract using real time RT-PCR. GalR1 and GalR2 mRNAs were detected in all segments with the highest levels in the large intestine and stomach, respectively. GalR3 mRNA levels were quite low and mostly confined to the colon. We also investigated the effect of galanin 1-16, which has high affinity for GalR1 and GalR2 and low affinity for GalR3 on depolarization-evoked Ca2+ increases in rat cultured myenteric neurons using Ca2+-imaging. Intracellular Ca2+ changes in myenteric neurons were monitored using the Ca2+ sensitive dye, fluo-4, and confocal microscopy. Galanin 1-16 (1 microM) markedly inhibited the K+-evoked Ca2+ increases in myenteric neurons. In summary, the differential distribution of GalRs supports the hypothesis that the complex effects of galanin in the gastrointestinal tract result from the activation of multiple receptor subtypes. Furthermore, this study confirms the presence of functional GalRs and suggests that galanin modulates transmitter release from myenteric neurons through inhibition of voltage-dependent calcium channels involving a G(i/o)-coupled GalR.     

Autonomic dysfunction and the gastrointestinal tract

Autonomic neuropathy of the gastrointestinal tract may represent a primary disorder, but much more often it is secondary due to systemic disorders like diabetes mellitus. This review gives an overview about the common clinical manifestations and the principles and limitations in diagnostic work-up of autonomic dysfunction of the gastrointestinal tract. Diagnostic evaluation usually includes a combination of screening tests for autonomic neuropathy and specialized diagnostic procedures for the detection of sequela of autonomic neuropathy in gastrointestinal motility.     

Diamonds in the coalface: new research in consultation-liaison psychiatry

PURPOSE OF REVIEW: Consultation-liaison psychiatry deals with patients who manifest both psychological and somatic symptoms and involves a close and collaborative interaction with other medical specialities. While it is a clinically rich area, resource constraints and service requirements have meant that it has perhaps contributed a little below its weight in academic terms. This review, although far from exhaustive, seeks to present some themes of recent research in this fascinating discipline. RECENT FINDINGS: The need to demonstrate the utility, and ensure the funding, of a service that is all too often regarded as 'non-core' by both mental health services and general hospitals remains constant. Useful work is being done in streamlining data collection, accurately measuring disability and improving outcomes for these complex and resource-intensive patients. Recent reviews have helped to clarify our understanding of medication-induced depression, the treatment options in self-harm, the place of psychosocial interventions in oncology, and the relationship between depression and heart disease among other areas. SUMMARY: Consultation-liaison psychiatry is a fascinating and underresearched field. Important work remains to be done in service delivery, diagnosis, treatment and outcome, as well as medical ethics and systems research. Although our knowledge is progressing, many existing studies are underpowered and multisite collaborations are necessary. Our patients carry an enormous burden of ill health and require the services of skilled clinicians, advocates and treatment brokers.     

Heterogeneity of enterochromaffin cells within the gastrointestinal tract

Enterochromaffin cells were the first endocrine cells of the gastrointestinal tract to be chemically distinguished, almost 150 years ago. It is now known that the chromaffin reaction of these cells was due to their content of the reactive aromatic amine, 5‐hydroxytryptamine (5‐HT, also known as serotonin). They have commonly been thought to be a special class of gut endocrine cells (enteroendocrine cells) that are distinct from the enteroendocrine cells that contain peptide hormones. The study by Martin et al. in the current issue of this journal reveals that the patterns of expression of nutrient receptors and transporters differ considerably between chromaffin cells of the mouse duodenum and colon. However, even within regions, chromaffin cells differ; in the duodenum there are chromaffin cells that contain both secretin and 5‐HT, cholecystokinin and 5‐HT, and all three of secretin, cholecystokinin, and 5‐HT. Moreover, the ratios of these different cell types differ substantially between species. And, in terms of function, 5‐HT has many roles, including in appetite, motility, fluid secretion, release of digestive enzymes and bone metabolism. The paper thus emphasizes the need to define the many different classes of enterochromaffin cells and relate this to their roles.     

c-Kit immunoreactive interstitial cells in the human gastrointestinal tract

c-Kit immunopositive cells are considered to be pacemakers and/or mediators of neurotransmission in the gastrointestinal tract. They also correspond to the interstitial cells of Cajal (ICs) in mice. The normal distribution of c-Kit positive cells and their relation to ICs in the human gastrointestinal tract remain unclear. In this study we examine the distribution of c-Kit positive cells and their ultrastructure in normal human tissue. We then classified them and examined their relationship to ICs. Thirty nine samples of gut from the esophagus to the sigmoid colon from humans (ranging in age from a 16 week old fetus to a 57 year old and without motility disorders), were processed for immunohistochemistry, electronmicroscopy and immuno-electronmicroscopy. c-Kit immunopositive cells were located in the external muscle from the lower esophagus to the sigmoid colon, wherever the external muscle was composed of smooth muscle cells, and they were classified morphologically into two groups. Cells in the first group were mainly spindle-shaped bipolar cells with few branches; these cells ran parallel to nearby smooth muscle. Ultrastructurally, they possessed many intermediate filaments and caveolae. The spindle-shaped cells were present in the esophagus, stomach and small intestine. The second group of cells were located only in the colon, and were multipolar or bipolar cells with numerous branches. Cells in the second group were also rich in caveolae and/or smooth endoplasmic reticulum, but intermediate filaments were not prominent. Although both groups of c-Kit immunopositive cells corresponded to ICs, some ICs in the human gut do not appear to express c-Kit immunoreactivity.     

Craniopharyngiomas in children: Turkey experience

Objectives Craniopharyngiomas are the most frequently encountered suprasellar tumors in children. Although they have a benign histology, total resection without morbidity is very difficult.Methods We aimed to review the results of pediatric craniopharyngioma patients treated in eight institutions in Turkey. There were 51 boys and 36 girls, ranging in age from 20 months to 18 years (mean 10.2 years). The most frequent symptom was headache, followed by visual disturbances. Hydrocephalus was seen most frequently in tumors greater than 4 cm in size (P=0.002). Hydrocephalus was associated with the decreased gross total resection (P=0.043). The recurrence (28%) was significantly higher in patients with subtotal and partial tumor removal (P=0.010). Bad outcome was significantly associated with tumor dimension (P=0.039); the greater the tumor dimension, the worse the outcome. Outcome was significantly better in patients older than 10 years (P=0.032). Gender, tumor type and location, presence of hydrocephalus and calcification, histological type of craniopharyngioma, and surgical approach did not have a significant effect on the outcome.Conclusions The treatment should be individualized and a multidisciplinary approach should be used. The goal of surgery should be gross total removal without mortality and with acceptable morbidity.     

Craniopharyngioma in children: Marseille experience

Objectives The management of craniopharyngioma in children represents a challenging problem. If radical excision is recommended by many authors as the initial treatment, in some cases, particularly in recurrent tumours, other methods (gamma knife surgery and intracystic bleomycin) can be very useful. Even if craniopharyngioma is a benign tumour, recurrences are frequent, and the aim of our study was to analyse our results, to try to determine some prognostic factors of recurrences and to discuss about a new strategy concerning the initial management of these tumours.Methods Forty-seven children with craniopharyngioma were treated in the Department of Pediatric Neurosurgery. All of the patients, but five children treated by intracystic bleomycin, underwent a surgical resection of the tumour as initial treatment with the goal of achieving gross total removal (GTR) of the tumour. Two children had radiotherapy and gamma knife treatment, respectively, following surgery for a tumoural residue. All the children had a magnetic resonance imaging (MRI) study 3 months after surgery to evaluate the results of the initial treatment. Using statistical analysis, some prognostic factors (age, sex, location, aspect, size of the tumour and result of the first MRI) have been studied.Results Forty-two children were operated on, but one died in the immediate postoperative period from a major stroke due to carotid spasm. GTR, defined as the absence of residue on the first MRI control, was achieved in 27 children (65.8%), but 7 patients (25.9%) presented recurrence. Subtotal removal (STR) was obtained in 14 children (34.2%), but 9 patients (64.3%) developed a recurrence defined as the growth of the residual tumour with or without clinical symptoms. Five children having a small- or moderate-size cystic craniopharyngioma were treated using one-stage (three cases) or two-stage (two cases) intracystic bleomycin and any presented recurrence. All the prognostic factors studied, except one (presence of a residue on the first MRI control), do not have a statistical significance.Conclusion Craniopharyngioma in children remains a formidable tumour, and regardless of whatever progress made in their management, the incidence of recurrences is still elevated and severe sequelae can be observed. There are no prognostic factors among those studied concerning the recurrences of these tumours except the quality of the exeresis confirmed by the first postoperative MRI.