Variability of tropism and replicative capacity of two naturally occurring influenza A H9N2 viruses in cell cultures from different tissues

Studies carried out on cell permissivity are of great interest to understand virus replication and pathogenicity. We described the results of a comparative analysis of replication efficiency of two naturally occurring influenza A H9N2 variants isolated from poultry and wild birds, differing by only two substitutions Q226L and T384N, in the receptor-binding site of haemagglutinin and the 380 loop region of NA proteins, respectively. Considering the overall growth of both viruses, lung cultures ensured the most efficient growth of TUN12L226N384 strain with titres up to 10⁹ TCID₅₀/ml whereas small intestine culture was highly susceptible to the TUN51Q226T384 virus reaching a titre of 10⁶ TCID50/ml. The lowest replication was shown in liver cells. The addition of trypsin was essential for the replication of either virus in primary fibroblasts, but it had a marginal positive effect on virus replication in the four other culture types with maximum titres of 10⁸ TCID₅₀/ml. This means that in chicken, the proteolytic activation of the H9N2 viruses with the cleavage motif RSSR may be mediated by other endoproteases than trypsin. Further investigations should concentrate on the production of the appropriate set of viruses by a reverse genetics approach and the examination of cellular protease expression in chicken tissues. This would lead to a more complete understanding of the tropism of low-pathogenic Influenza A viruses.     

Rethinking chronic pain in a primary care setting

Chronic pain substantially impacts patient function and quality of life and is a burden to society at large in terms of increased health care utilization and loss of productivity. As a result, there is an increasing recognition of chronic pain as a public health crisis. However, there remains wide variability in clinical practices related to the prevention, assessment, and treatment of chronic pain. Certain fundamental aspects of chronic pain are often neglected including the contribution of the psychological, social, and contextual factors associated with chronic pain. Also commonly overlooked is the importance of understanding the likely neurobiological mechanism(s) of the presenting pain and how they can guide treatment selection. Finally, physicians may not recognize the value of using electronic medical records to systematically capture data on pain and its impact on mood, function, and sleep. Such data can be used to monitor onset and maintenance of treatments effects at the patient level and evaluate costs at the systems level. In this review we explain how these factors play a critical role in the development of a coordinated, evidence-based treatment approach tailored to meet specific needs of the patient. We also discuss some practical approaches and techniques that can be implemented by clinicians in order to enhance the assessment and management of individuals with chronic pain in primary care settings.     

Economic and clinical burden of opioid-induced nausea and vomiting

Opioids are the standard of care for treating moderate-to-severe pain; however, their efficacy can be limited by adverse events (AEs), including nausea and vomiting. Opioid-induced nausea and vomiting (OINV) is an inherent adverse effect of opioid treatment, exerting effects centrally and peripherally. Opioid-related AEs can impact treatment adherence and discontinuation, which can result in inadequate pain management. OINV may persist long-term, negatively affecting patient functional outcomes, physical and mental health, patient satisfaction, and overall costs of treatment. Multiple factors may contribute to OINV, including activation of opioid receptors in the chemoreceptor trigger zone, vestibular apparatus, and gastrointestinal tract. Prophylactic or early treatment with antiemetics may be appropriate for patients who are at high risk for OINV.     

Ketamine for chronic pain: risks and benefits

The anaesthetic ketamine is used to treat various chronic pain syndromes, especially those that have a neuropathic component. Low dose ketamine produces strong analgesia in neuropathic pain states, presumably by inhibition of the N-methyl-D-aspartate receptor although other mechanisms are possibly involved, including enhancement of descending inhibition and anti-inflammatory effects at central sites. Current data on short term infusions indicate that ketamine produces potent analgesia during administration only, while three studies on the effect of prolonged infusion (4–14 days) show long-term analgesic effects up to 3 months following infusion. The side effects of ketamine noted in clinical studies include psychedelic symptoms (hallucinations, memory defects, panic attacks), nausea/vomiting, somnolence, cardiovascular stimulation and, in a minority of patients, hepatoxicity. The recreational use of ketamine is increasing and comes with a variety of additional risks ranging from bladder and renal complications to persistent psychotypical behaviour and memory defects. Blind extrapolation of these risks to clinical patients is difficult because of the variable, high and recurrent exposure to the drug in ketamine abusers and the high frequency of abuse of other illicit substances in this population. In clinical settings, ketamine is well tolerated, especially when benzodiazepines are used to tame the psychotropic side effects. Irrespective, close monitoring of patients receiving ketamine is mandatory, particularly aimed at CNS, haemodynamic, renal and hepatic symptoms as well as abuse. Further research is required to assess whether the benefits outweigh the risks and costs. Until definite proof is obtained ketamine administration should be restricted to patients with therapy-resistant severe neuropathic pain.     

Is This Phantom Pain?

Right upper quadrant abdominal pain may be due to many causes, and at times may give rise to diagnostic dilemma. We present here a young lady with biliary type of pain who was eventually found to have gall bladder agenesis with aerobilia, in the absence of prior biliary intervention.     

Pain in birds: a review for veterinary nurses

Pain assessment and management in animals is still a new and growing field of research. Although it is still early days for pain research in birds, this article aims to provide information on the pain behaviours known so far, and describes current analgesic drugs and doses.