Neuroinflammation and the generation of neuropathic pain

Inflammation is the process by which an organism responds to tissue injury involving both immune cell recruitment and mediator release. Diverse causes of neuropathic pain are associated with excessive inflammation in both the peripheral and central nervous system which may contribute to the initiation and maintenance of persistent pain. Chemical mediators, such as cytokines, chemokines, and lipid mediators, released during an inflammatory response have the undesired effect of sensitizing and stimulating nociceptors, their central synaptic targets or both. These changes can promote long-term maladaptive plasticity resulting in persistent neuropathic pain. This review aims to provide an overview of inflammatory mechanisms at differing levels of the sensory neuroaxis with a focus on neuropathic pain. We will compare and contrast neuropathic pain states such as traumatic nerve injury which is associated with a vigorous inflammatory response and chemotherapy induced pain in which the inflammatory response is much more modest. Targeting excessive inflammation in neuropathic pain provides potential therapeutic opportunities and we will discuss some of the opportunities but also the clinical challenges in such an approach.

Contamination and current practice in decontamination pof nebulisers in ventilated patients

To examine the incidence of contamination and current practice of decontamination of nebulisers after use within a ventilator circuit, in public- and private sector intensive care units (ICUs) in Johannesburg; to assess the presence of and adherence to a decontamination protocol in these ICUs and to identify which practices were associated with lower or no bacterial growth. Methods: A cross-sectional study design was used which included a semi-structured interview with the ICU manager and an audit of current nebuliser practice. Nebulisers that were identified in the interview were swabbed and streaked on blood agar plates (BAPs). BAPs were incubated and assessed for bacterial colonisation, number of colony forming units (CFUs) and number of different species of CFUs present. Results: Two hundred and sixty-nine ICU beds were surveyed over a two-month period resulting in 45 nebulisers used within a ventilator circuit that could be tested. The majority (93%) were single-use jet nebulisers, all were being re-used and 52% presented with contamination. None of the ICUs had a nebuliser decontamination protocol in place. Contaminated nebulisers that were stored in a sterile drape had significantly higher concentrations of bacterial growth (p=0.03). Conclusion: The rate of colonisation of re-used jet nebulisers is high. Nebuliser decontamination protocols are urgently needed.

Defining the endoscopic appearances of tylosis using conventional and narrow-band imaging: a case series

Tylosis is an autosomal dominant skin disorder strongly associated with esophageal squamous cell cancer. We present a single-operator experience of utilizing conventional endoscopy and narrow-band imaging with magnification to characterize esophageal appearances in tylosis. Nineteen consecutive patients with tylosis attending for surveillance endoscopy were studied. White-light imaging (WLI) and narrow-band imaging (NBI) were undertaken, with magnification being performed as necessary. On WLI, we classified 12 patients as having mild change, 5 moderate change, and 2 severe change. WLI can define changes to the esophageal mucosa of variable hyperkeratosis and identify more significant focal abnormalities. NBI enhances these mucosal changes, and NBI with magnification can demonstrate intrapapillary capillary loop changes compatible with dysplasia, prompting consideration of surgery. This report is the first to characterize the endoscopic appearances in tylosis.

40 Gbit/s asynchronous digital optical regenerator

We present the first experimental demonstration of an asynchronous digital optical regenerator at 42.67 Gbit/s. The system effectively retimes incoming asynchronous data bursts to a local clock without burst mode clock recovery and converts the signal to a desired wavelength and duty cycle.

Inherited predisposition to colorectal adenomas caused by multiple rare alleles of MUTYH but not OGG1, NUDT1, NTH1 or NEIL 1, 2 or 3

BACKGROUND

MUTYH-associated polyposis (MAP) is a recessive trait characterised by multiple colorectal adenomas and a high risk of colorectal cancer. MUTYH functions in the DNA base excision repair pathway and has a key role in the repair of oxidative DNA damage.

OBJECTIVES

To assess the contribution of inherited variants in genes involved in base excision repair and oxidative DNA damage including MUTYH, OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1 to the multiple colorectal adenoma phenotype.

METHODS

Inherited variants of MUTYH, OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1 were sought in 167 unrelated patients with multiple colorectal adenomas whose family histories were consistent with recessive inheritance. These variants were also characterised in approximately 300 population controls.

RESULTS

Thirty-three patients (20%) and no controls were MUTYH homozygotes or compound heterozygotes (ie, carried two mutations) and therefore had MAP. Eight different pathogenic MUTYH mutations were identified, of which four were novel. MAP cases had significantly more adenomas than non-MAP cases (p = 0.0009; exact test for trends in proportions) and presented earlier (p = 0.013; analysis of variance). Twenty-four protein-altering variants were identified upon screening of OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1. However, all combinations of two (or more) variants that were identified at an individual locus in patients were also seen in controls, and no variants were significantly over-represented (or under-represented) in cases.

CONCLUSION

Multiple rare alleles of MUTYH are associated with autosomal recessive MAP, while OGG1, NEIL1, NEIL2, NEIL3, NUDT1 and NTH1 do not contribute significantly to autosomal recessive polyposis.

Clinical trial: randomized study of clarithromycin versus placebo in active Crohn's disease

BACKGROUND

Crohn's disease is characterized by defective innate immune responses to intestinal bacteria. Clarithromycin is a broad-spectrum antibiotic that has good penetration into macrophages.

AIM

To assess the efficacy of clarithromycin in active Crohn's disease.

METHODS

Patients with Crohn's disease activity index > 200 and serum C-reactive protein > or = 10 mg/L were randomized to receive clarithromycin 1 g o.d. or placebo for 3 months. Patients taking more than 10 mg/day prednisolone or 3 mg/day budesonide were excluded. Primary outcome was remission (CDAI < or = 150) or response (fall in CDAI > or = 70 from pre-treatment level) at 3 months.

RESULTS

The trial was stopped after 41 patients had been recruited because of poor overall efficacy. There was no difference in combined remission or response rates at 3 months between clarithromycin: 26% (five of 19) and placebo: 27% (six of 22) (P = 1.00). The mean (s.d.) fall in Crohn's disease activity index was 35 (80) clarithromycin and -2 (114) placebo (P = 0.24). However, post hoc analysis showed a significant difference in response/remission determined by Crohn's disease activity index after 1 month: 53% (10 of 19) clarithromycin vs. 14% (three of 22) placebo (P = 0.01).

CONCLUSION

Clarithromycin 1 g for 3 months is ineffective in active Crohn's disease but possible benefit was observed at 1 month, suggesting that an initial effect may be attenuated by subsequent bacterial resistance.