Methoxetamine: prevalence of use in the USA and UK and associated urinary problems

Background: Methoxetamine is a novel psychoactive substance and a legal alternative to ketamine in many countries, including parts of the United States. Frequent recreational ketamine use can cause lower urinary tract symptoms, whereas methoxetamine was originally marketed as “bladder friendly”.

Aims: (1) To determine changes in prevalence of methoxetamine use between 2011 and 2012 in the USA and UK and (2) to investigate the prevalence of urinary symptoms in group of methoxetamine users, who had also used ketamine at least once in their lifetime.

Methods: Cross-sectional, anonymous online surveys exploring patterns of drug use were conducted in late 2011 (n?=?15?200) and late 2012 (n?=?22?289).

Results: Reported lifetime, past 12 months, and last month methoxetamine use significantly increased in the USA between 2011 and 2012; whereas, during the same period, past 12 months and last month methoxetamine use significantly decreased in the UK. Of the methoxetamine users questioned in the 2012 survey, 23.0% (n?=?98) reported experiencing urinary symptoms. Prevalence of at least one urinary symptom was related to frequency of methoxetamine use in the last month.

Conclusions: Methoxetamine use appeared to increase in the United States and decrease in the UK between 2011 and 2012. Approximately, one-quarter of methoxetamine users questioned reported urinary symptoms; however, previous ketamine use cannot be ruled out as the cause of the symptoms.     

Tuberculosis research update

Tuberculosis (TB) remains a major challenge to global public health in the 21st century. In 2007, there were an estimated 9.27 million new cases and 1.3 million deaths among HIV‐negative patients with TB. The HIV‐associated TB epidemic, drug‐resistant disease, the need for better diagnostic assays and the limited efficacy of Bacille Calmette–Guerin vaccination are four important obstacles to further progress in global TB control. In this brief review, we provide a focused update on these four key areas of TB research.     

The mental health expert patient: findings from a pilot study of a generic chronic condition self-management programme for people with mental illness

BACKGROUND: Less than optimal outcomes and escalating costs for chronic conditions including mental illness have prompted calls for innovative approaches to chronic illness management. AIMS: This study aimed to test the feasibility and utility of combining a generic, clinician administered and peer-led self-management group approach for people with serious mental illness. METHOD: General practitioners and mental health case managers used a patient-centred care model (the Flinders model) to assist 38 patients with serious mental illness to identify their self-management needs, and match these with interventions including Stanford peer-led, self-management groups and one-to-one peer support. Self-management and quality of life outcomes were measured and qualitative evaluation elicited feedback from all participants. RESULTS: Collaborative care planning, combined with a problems and goals focused approach, resulted in improved self-management and mental functioning at 3 to 6 months follow-up. The Stanford self-management course was applicable and acceptable to patients with serious mental illnesses. Qualitative feedback was highly supportive of this approach. CONCLUSIONS: Generic, structured assessment and care planning approaches, resulting in self-management education targeted to the individual, improved self-management and quality of life. Patients and service providers reported considerable gains despite the challenges associated with introducing a generic model within the mental health and general practice sector.     

Analysis of fracture and deformation modes in teeth subjected to occlusal loading

An analysis of fracture and deformation modes in tooth enamel subjected to occlusal loading is presented. Several competing modes are identified: deformation by yield beneath the indenter; median cracking from the ensuing plastic zone and analogous radial cracking from the dentin–enamel junction along the load axis; and margin cracking from the cervical enamel–cement junction. The analysis, based on a simple model of tooth geometry, presents relations for the critical loads to initiate these damage modes within the enamel, and to drive ensuing cracks longitudinally around the tooth walls to failure. The relations are explicit in their dependence on characteristic tooth dimensions – enamel thickness and cuspal radius – and on material properties – modulus, hardness, toughness and strength. Provision is made to incorporate properties of the occlusal contact, whether from opposing dentition or intervening food particles. All these features are demonstrated on critical-load master diagrams. A characteristic feature of the damage evolution is the gradual evolution of each mode with increasing load, so that failure is generally a prolonged rather than abrupt event. This accounts for the remarkable damage tolerance of natural teeth. The equations may enable basic predictions of tooth responses for humans and animals under a variety of specified dietary and functional conditions.     

Predicting failure in mammalian enamel

Dentition is a vital element of human and animal function, yet there is little fundamental knowledge about how tooth enamel endures under stringent oral conditions. This paper describes a novel approach to the issue. Model glass dome specimens fabricated from glass and back-filled with polymer resin are used as representative of the basic enamel/dentine shell structure. Contact loading is used to deform the dome structures to failure, in simulation of occlusal loading with opposing dentition or food bolus. To investigate the role of enamel microstructure, additional contact tests are conducted on two-phase materials that capture the essence of the mineralized-rod/organic-sheath structure of dental enamel. These materials include dental glass-ceramics and biomimicked composites fabricated from glass fibers infiltrated with epoxy. The tests indicate how enamel is likely to deform and fracture along easy sliding and fracture paths within the binding phase between the rods. Analytical relations describing the critical loads for each damage mode are presented in terms of material properties (hardness, modulus, toughness) and tooth geometry variables (enamel thickness, cusp radius). Implications in dentistry and evolutionary biology are discussed.