Peritoneal dialysis has now become an established form of renal replacement therapy; nearly half the patients on dialysis in the UK are treated in this way. Survival of patients is now equal to that with haemodialysis. However, long-term peritoneal dialysis (>8 years) is limited to a small percentage of patients because of dropout to haemodialysis for inherent complications of peritoneal dialysis--peritonitis, peritoneal access, inadequate dialysis, and patient-related factors. However, improvements in the understanding of the pathophysiological processes involving the peritoneal membrane have paved the way for advances in the delivery of adequate dialysis, more biocompatible dialysis fluids, and automated peritoneal dialysis. Other technical advances have led to a reduction in peritonitis. Peritoneal dialysis is an important dialysis modality and should be used as an integral part of RRT programmes.

It is clear that the prion strain causing bovine spongiform encephalopathy (BSE) in cattle has infected human beings, manifesting itself as a novel human prion disease, variant Creutzfeldt-Jakob disease (CjD). Studies of the incubation periods seen in previous epidemics of human prion disease and of the effect of transmission barriers limiting spread of these diseases between species, suggest that the early variant CJD cases may have been exposed during the preclinical phase of the BSE epidemic. It must therefore be considered that many cases may follow from later exposure in an epidemic that would be expected to evolve over decades. Since the number of people currently incubating this disease is unknown, there are concerns that prions might be transmitted iatrogenically via blood transfusion, tissue donation, and, since prions resist routine sterilisation, contamination of surgical instruments. Such risks remain unquantified. Although variant CJD can be diagnosed during life by tonsil biopsy, a prion-specific blood test is needed to assess and manage this potential threat to public health. The theoretical possibility that BSE prions might have transferred to other species and continue to present a risk to human health cannot be excluded at present.

For more than 20 years, moderately raised concentrations of total homocysteine (tHcy) have been associated with an increased risk of atherothrombotic vascular events but only recently has evidence mounted to suggest that the association may be causal. The association is independent of other factors, it is fairly consistent across many studies, it is strong and dose-related, and it is biologically plausible. However, the evidence needs to be strengthened by a systematic review of all comparable studies and the demonstration, in randomised trials, that lowering tHcy is followed by a significant reduction in atherothrombotic vascular disease. In addition, the measurement of tHcy needs to be standardised. If these can be achieved then tHcy measurement will become another useful marker of vascular risk, multivitamin therapy will be another therapeutic option for people at risk of atherothrombotic vascular disease, and fortification of food with folic acid will rise high on the political and public health agenda.

The prevalence of psychiatric disorders is increased in children and adults with intellectual disability. Brain damage or dysfunction interact with social and family factors to increase susceptibility to mental illness. Psychiatric disorders in the context of genetic syndromes are commonly overlooked, and there is substantial underdiagnosis of mental disorders because of the atypical and non-specific clinical presentations, and the frequent assumption that psychiatric symptoms are an inherent part of the underlying intellectual disability. There is a strong need for evidence-based practice in the prescribing and monitoring of drugs in this population, especially since many of the drugs are unlicensed for use in children. There is an urgent need to understand and establish the pharmacokinetics, pharmacodynamics, and side-effect profiles of psychotropic medication in this population. Positive trends in pharmacotherapy include the use of atypical antipsychotics instead of the classic antipsychotics, serotonin-specific reuptake inhibitors (SSRIs) rather than tricyclic antidepressants, and newer antiepileptic drugs. Another welcome trend is the use of SSRIs instead of antipsychotics in the long-term management of challenging behaviour in this population.

Peroxisome proliferator-activated receptors (PPAR) were discovered in 1990, ending 25 years of uncertainty about the molecular mechanisms of peroxisome proliferation. Subsequently, PPARs have improved our understanding of adipocyte differentiation. But there is more to PPARs than solving a puzzle about an organelle (the peroxisome) long considered an oddity, and their medical significance goes beyond obesity too. Enhanced PPAR type alpha expression protects against cardiovascular disorders though the role of enhanced PPARgamma expression seems less favourable. PPAR mechanisms, mainly via induction of more differentiated cell phenotypes, protect against some cancers. The differentiation of many cell types (hepatocyte, fibroblast, adipocyte, keratinocyte, myocyte, and monocyte/macrophage) involves PPARs, and these nuclear receptors are now attracting the attention of many medical specialties and the pharmaceutical industry.

Tissue repair involves a close interplay between growth factors and cell adhesion molecules. The normal healing process may be disrupted by pathophysiological states such as inflammation, due to loss of growth factors, cell adhesion molecules, or both, which results in a reduced rate of healing. Such events may occur in inflammatory bowel disease during mucosal restitution. We postulate that the beneficial response to heparin observed in inflammatory bowel disease may result from mechanisms in addition to anticoagulation. These include the restoration of high-affinity receptor binding by antiulcerogenic growth factors, such as basic fibroblast growth factor, that normally rely on the presence of heparan sulphate proteoglycans, such as syndecan-1, as co-receptors. Loss of syndecan-1 has been observed in the ulcerated mucosa of patients with inflammatory bowel disease. This loss may lead to impaired binding of basic fibroblast growth factor and a reduced rate of ulcer healing. We suggest that heparin restores high-affinity receptor binding of basic fibroblast growth, and so increases the rate of mucosal recovery.

Pain is a perceived threat or damage to one's biological integrity. Suffering is the perception of serious threat or damage to the self, and it emerges when a discrepancy develops between what one expected of one's self and what one does or is. Some patients who experience sustained unrelieved pain suffer because pain changes who they are. At a physiological level, chronic pain promotes an extended and destructive stress response characterised by neuroendocrine dysregulation, fatigue, dysphoria, myalgia, and impaired mental and physical performance. This constellation of discomforts and functional limitations can foster negative thinking and create a vicious cycle of stress and disability. The idea that one's pain is uncontrollable in itself leads to stress. Patients suffer when this cycle renders them incapable of sustaining productive work, a normal family life, and supportive social interactions. Although patients suffer for many reasons, the physician can contribute substantially to the prevention or relief of suffering by controlling pain. Suffering is a nebulous concept for most physicians, and its relation to pain is unclear. This review offers a medically useful concept of suffering that distinguishes it from pain, accounts for the contributory relation of pain to suffering by describing pain as a stressor, and explores the implications of these ideas for the care of patients.

Opioids are our most powerful analgesics, but politics, prejudice, and our continuing ignorance still impede optimum prescribing. Just over 100 years ago, opium poppies were still grown on the Cambridgeshire fens in the UK to provide oblivion for the working man and his family, but the brewing lobby argued on thin evidence that their potions were less dangerous. The restriction of opioid availability to protect society and the individual continues in many countries. In this review I focus on chronic and cancer pain, but many of the principles apply in acute pain. The justification for this focus is that patients with chronic pain may suffer longer and unnecessarily if we prescribe and legislate badly.

Visceral pain is the most common form of pain produced by disease and one of the most frequent reasons why patients seek medical attention. Yet much of what we know about the mechanisms of pain derives from experimental studies of somatic not visceral nociception. The conventional view is that visceral pain is simply a variant of somatic pain, a view based on the belief that a single neurological mechanism is responsible for all pain. However, the more we learn about the mechanisms of somatic and visceral pain, the more we realise that although these two processes have much in common, they also have important differences. Although visceral pain is an important part of the normal sensory repertoire of all human beings and a prominent symptom of many clinical conditions, not much clinical research has been done in this field and there are few clinical scientists with expertise in the management of visceral pain. Instead, visceral pain is usually treated by a range of specialists who take quite different approaches to the management of this type of pain. Thus, the management of visceral pain is frequently unsatisfactory. In this review, we consider visceral pain as a separate form of pain and examine its distinct sensory properties from a clinical perspective. We describe recent research findings that may change the way we think about visceral pain and, more importantly, may help develop new procedures for its management.

Postanaesthesia care units used to echo with cries of patients in pain after general anaesthesia. Each as-needed dose of analgesia was given only after permission of the surgeon or anaesthesiologist. Once conscious, patients were required to request each subsequent analgesic dose until hospital discharge. Not surprisingly, nearly half the patients who have an operation experience moderate to severe pain after surgery. Acute pain control has advanced dramatically and is now a field with dedicated texts, journals, and research. Despite improved surgical techniques that have transformed many operations into same-day procedures, inadequately controlled pain may still extend the length of hospital stay and predispose to expensive, time-consuming complications such as pneumonia. Recognition of economic and humanitarian benefits of pain control has prompted worldwide attention from professional groups, insurers, and governments. This paper describes the process of acute pain and measures to control it with drugs or non-pharmacological interventions. Even brief intervals of acute pain can induce long-term neuronal remodelling and sensitisation ("plasticity"), chronic pain, and lasting psychologial distress. Hence, acute pain and other types of pain (cancer-related or chronic) that are classified as distinct actually have many similarities.