Comparison of Pain-Like behaviors in two surgical incision animal models in C57BL/6J mice

BACKGROUND

Management of pain post-surgery is crucial for tissue healing in both veterinary and human medicine. Overuse of some analgesics such as opioids may lead to addictions and worsen pain syndromes (opioid-induced hyperalgesia), while underuse of it may affect the welfare of the patient. Therefore, the importance of using surgery models in laboratory animals is increasing, with the goal of improving our understanding of pain neurobiology and developing safer analgesics.

METHODS

We compared the widely used plantar incision model with the laparotomy surgery model and measured pain-related behaviors using both spontaneous and evoked responses in female and male C57BL/6J mice. Additionally, we assessed conditioned place preference (CPP) and sucrose preference tests to measure pain-induced motivation for the analgesic ketoprofen and anhedonia-like behavior.

RESULTS

Laparotomized mice showed increased abdominal sensitivity while paw-incised mice showed increased paw thermal and mechanical sensitivity up to seven days post-surgery. Laparotomy surgery reduced all spontaneous behaviors in our study however this effect dissipated by 24 h post-laparotomy. On the other hand, paw incision only reduced the percentage of cage hanging in a sex-dependent manner at 6 h post-incision. We also showed that both surgery models increased conditioned place preference for ketoprofen while preference for sucrose was only reduced at 24 h post-laparotomy. Laporatomy, but not paw incision, induced a decrease in body weight at 24 h post-surgery. Neither surgery model affected fluid intake.

CONCLUSION

Our results indicate that post-surgery hypersensitivity and behavioral deficits may differ by the incision site. Furthermore, factors associated with the surgery including length of the incision, duration of the anesthesia, and the layers that received stitches may affect subsequent spontaneous behaviors. These findings may help to improve drug development or the choice of the effective analgesic, depending on the surgery type.

The Body Composition Monitor: a flexible tool for routine fluid management across the haemodialysis population

Bioimpedance measurements with the Body Composition Monitor (BCM) have been shown to improve fluid management in haemodialysis. However, there is a lack of a sufficiently robust evidence-base for use of the BCM outside of standard protocols. This study aims to characterise BCM measurement variation to allow users to make measurements and interpret the results with confidence in a range of clinical scenarios. BCM measurements were made in 48 healthy controls and in 48 stable haemodialysis patients before and immediately after dialysis. The effect of utilising alternative measurement paths was assessed using mixed effects models and the effect of measuring post-dialysis was assessed by comparing changes in BCM-measured overhydration (OH) with weight changes over dialysis. The data from healthy controls suggest that there is no difference in BCM-measured OH between all the whole-body paths other than the foot-to-foot measurement. Dialysis patients showed similar results other than having higher BCM-measured OH when measured across the site of a vascular access. There was good agreement between BCM-measured OH and change in weight, suggesting post-dialysis measurements can be utilised. These results suggest BCM protocols can be flexible regarding measurement paths and timing of measurement to ensure as many patients as possible can benefit from the technology.

Unexpected triggering of the dialysate blood leak detector by haemolysis

This case showed that it is possible for haemoglobin released by haemolysis in the extracorporeal circuit to pass through a high permeability (albumin retaining) dialyser membrane. In the incident described, the blood leak detector of the dialysis machine was activated before the patient became symptomatic. Haemolysis should be considered as a possible cause of blood leak alarms during dialysis with high flux membranes.

DEVELOPMENT OF INDICATORS TO MEASURE

This paper describes a study to capture the key roles and activities of nephrology nurses across different countries in Europe. The concept of the study and the need to clarify the activities of the nephrology nurse arose as part of a larger study to develop the European Practice Database (EPD) (1). The Research Board (EDTNA/ERCA) needed to identify key questions that would detect significant differences in the role and responsibilities of nephrology nurses in different countries and monitor the evolution over time of nephrology nursing practice in Europe. It was therefore appropriate to devise a separate small study to generate evidence based questions for the EPD and confirm the reliability and usefulness of the information captured.

SERO-CONVERSION OF HCV NEGATIVE PATIENTS: A EUROPEAN STUDY ON SERO-CONVERSION OF HCV NEGATIVE PATIENTS: A EUROPEAN STUDY ON

This paper reports part of the findings from a larger study reported earlier, the European study on epidemiology and the management of HCV in the haemodialysis population (1). Centres recruited to the larger study were monitored for a further one year observation period to measure and generate a deeper understanding of HCV sero-conversion. From 4724 patients who were studied at the baseline, in 68 centres, only 13 patients were found to have sero-converted. These sero-conversions occurred in 7 hospitals within 5 different countries. Possible routes of transmission and risk factors are described with respect to the individual centres and good practice recommendations based on current evidence presented.

POST INSERTION CATHETER CARE IN PERITONEAL DIALYSIS CENTRES ACROSS EUROPE: RESULTS OF THE POST INSERTION PROJECT OF THE RESEARCH BOARD

The EDTNA/ERCA survey of Post Insertion Catheter Care in Peritoneal Dialysis (PICC) was a project organised through the Collaborative Research Programme (CRP) of the EDTNA/ERCA. In this survey, data were collected from 54 participating centres in 20 countries. From this survey it became clear that there is no standardised approach to immediate post-catheter insertion treatment protocols. If we want to reduce technique failure of PD related to catheter failure, a first step will be to investigate the different policies used in Europe in order to evaluate the outcome results derived from different policies in post insertion catheter care.

European study on epidemiology and management of hepatitis C virus (HCV) infection in the haemodialysis population. Part 3: prevalence and incidence

An analysis of the literature showed a high prevalence of HCV in the European dialysis population in the nineties. The prevalence was similar in most countries in northern Europe, but infection was more common in France, Italy, Spain, Portugal and Greece (1) and in Eastern European countries (2). The reported prevalence of anti-HCV-positive patients in the EDTA registry was 21% in 1992 and 18% in 1993 (3) ranging from 1% in Finland to 42% in Egypt (4). The incidence of HCV, in new patients starting renal replacement therapy, ranged from 3% to 7% (5,6) and reported seroconversion rates during dialysis treatment varied between 1% (7) and 16% (8) per year.

Technological advances in renal care

The first systems for treating kidney failure were developed in the 1940's, when it was found that blood could be successfully cleared of toxins and returned to the body using a relatively simple device based on artificial sausage skin wrapped around a wooden frame. This process was used to replace the function of the kidney, allowing patients to recover from conditions such as poisoning or crush injuries that temporarily stop the kidneys working. In the 1960's, advances in technology made long-term replacement of renal function using haemodialysis machines possible and allowed surgeons to carry out kidney transplants between people who were not identical twins. Long-term peritoneal dialysis became a viable treatment option two decades later. There are now over 1.1 million people world-wide receiving regular dialysis treatment and around 340,000 people living with a donated kidney. This paper reviews the pioneering work in the treatment of kidney failure and looks at some of the recent advances in equipment design, materials science, immunosuppression and information technology that aim to improve the quality of life and the life expectancy for patients living on renal replacement therapy.

Leucocyte entry and endothelial E-selectin expression following intradermal Propionibacterium acnes administration

Immune responses in porcine skin to intradermal inoculation of heat-killed Propionibacterium acnes (HKPA), the major bacterial agent associated with human inflammatory acne, were studied. Pigs were chosen as experimental animals because their skin is similar in structure and composition to that of man and because the use of genetically inbred pigs enables leucocytes to be transferred between animals without eliciting rejection responses. Two pigs were sensitized intradermally with 10 mg of HKPA and were challenged 2 weeks later with doses ranging from 1-100 microg of HKPA in various intradermal sites on the ventral aspect of the abdomen. Four further pigs, previously sensitized with Bacillus Calmette-Guérin (BCG) but not HKPA, were challenged with purified protein derivative (PPD) of bovine tuberculin and HKPA. Entry of(51)Cr-labelled peripheral blood lymphocytes (PBLs) over 48 h was studied in all the challenge sites. Peak PBL entry occurred at 4 h, remaining sustained up to 24 h. There was a dose-dependent effect of HKPA on the level of PBL entry, which was antigen-specific, as few leucocytes were seen in PPD-challenge sites in HKPA-sensitized pigs or in HKPA-challenged sites in BCG-sensitized pigs. There was also a substantial influx of(111)Indium-labelled neutrophils into the lesions. Lymphocytes present were predominantly of the CD3(+)CD2(+)T-cell subset, although gammadelta TCR(+)cells were present also, particularly after 24 h. E-selectin was markedly upregulated on dermal endothelium in the P. acnes sites. The histological infiltration and kinetics were similar to those reported in human inflammatory acne.

CE marking & the MDD: what difference will the new regulations make?

CE marks are symbols used to show that products comply with regulations, or 'Directives', issued by the Council of Ministers of the European Commission. The EC Directives cover all kinds of products, from toys to construction materials. They are intended to make it easier for manufacturers to sell their products throughout the European Community. There will be three directives for medical devices.

Notified bodies. Questions and answers

Under the new system of regulation, many companies will need to develop working relationships with Notified Bodies to achieve approval to affix the CE mark to their products. This article answers some pertinent questions relating to Notified Bodies in general, and describes the situation in the United Kingdom.