Challenges and pitfalls of experimental bariatric procedures in rats

Introduction: The impact of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on obesity and obesity-related diseases is unquestionable. Up to now, the technical descriptions of these techniques in animals/rats have not been very comprehensive. Methods: For SG and RYGB, operating time, learning curve, and intraoperative mortality in relation to weight of the rat and type of anesthesia were recorded. Furthermore, a review of the literature on experimental approaches towards SG and RYGB in rats was carried out, merging in a detailed technical description for both procedures. Results: The data presented here revealed that the mean operating time for SG (69.4 +/- 22.2 min (SD)) was shorter than for RYGB (123.0 +/- 20.7 min). There is a learning curve for both procedures, resulting in a reduced operating time of up to 60% in SG and 35% in RYGB (p < 0.05; t-test). However, with increased weight, operating time increases to about 80 min for SG and about 120 min for RYGB. Obese rats have an increased intraoperative mortality rate of up to 50%. After gaseous anesthesia the mortality can be even higher. The literature search revealed 40 papers dealing with SG and RYGB in rats. 18 articles (45%) contained neither photographs nor illustrations; 14 articles (35%) did not mention the applied type of anesthesia. The mortality rate was described in 15 papers (37.5%). Conclusion: Experimental obesity surgery in rats is challenging. Because of the high mortality in obese rats operated under gaseous anesthesia, exercises to establish the techniques should be performed in small rats using intraperitoneal anesthesia. Copyright (C) 2012 S. Karger GmbH, Freibur

Pharmacogenetic allele nomenclature: International workgroup recommendations for test result reporting

This manuscript provides nomenclature recommendations developed by an international workgroup to increase transparency and standardization of pharmacogenetic (PGx) result reporting. Presently, sequence variants identified by PGx tests are described using different nomenclature systems. In addition, PGx analysis may detect different sets of variants for each gene, which can affect interpretation of results. This practice has caused confusion and may thereby impede the adoption of clinical PGx testing. Standardization is critical to move PGx forward

Value judgments and the choice of climate protection strategies

In this paper, we critically review cost-benefit analysis, cost-effectiveness analysis and the guard-rail approach as decision-support tools for the choice of climate protection strategies. Our main focus is on the central role of value judgments, which arise from the need to value; first, uncertain environmental benefits from climate protection relative to other goods; second, the consumption of the present relative to future generations; and third the consumption of rich relative to poor people. Each of the three approaches analyzed has its shortcomings. Cost-benefit analysis requires a complete and transitive preference ordering, which stands in sharp contrast to scientific uncertainties and valuation problems. Cost-effectiveness analysis suffers from the difficulty of setting an appropriate climate protection target. Finally, the usefulness of the guard-rail approach for decision-makers depends on the extent to which it is possible to limit the choice set

Midterm functional outcome after dorsal capsular imbrication for posttraumatic instability of the distal radioulnar joint

Introduction The dorsal capsular imbrication of the distal radioulnar joint (DRUJ) which was performed because of posttraumatic dorsal instability showed promising functional results after the first postoperative years. Therefore, we hypothesized that patients after capsular imbrication are characterized by good subjective and functional outcome measurements after a midterm period. Materials and methods Eleven patients (range 21-50 years of age; median 35 years of age) were examined after capsular imbrication of the DRUJ because of posttraumatic instability with a mean follow-up time of 72 months (range 46-114 months; median 66 months). Examination parameters included the determination of range of motion (ROM), grip strength, pain and functional outcome scores (modified Mayo wrist score (MMWS); Disabilities of the Arm, Shoulder and Hand questionnaire (DASH score)). Results A mean DASH score of 6.7 (range 0-22.5) and mean MMWS of 91.8 (range 75-100) were measured. Grip strength reached 96.7 % of the contralateral hand. Range of motion reached at least 93.1 % of the contralateral hand. Eight of 11 patients regarded functional outcome and pain reduction as excellent. Six of 11 patients did not recognize a diagnosed instability of DRUJ as such. Ulnar-sided wrist pain was the apparent symptom in these cases. Conclusions Capsular imbrication of the DRUJ is a reliable and sufficient treatment option in case of posttraumatic dorsal instability. Since DRUJ instability is seldom recognized by the patients as such, a standardised diagnostic algorithm is mandatory to guarantee reliability and efficacy for identifying DRUJ instability

CD133: enhancement of bone healing by local transplantation of peripheral blood cells in a biologically delayed rat osteotomy model.

Sufficient angiogenesis is crucial during tissue regeneration and therefore also pivotal in bone defect healing. Recently, peripheral blood derived progenitor cells have been identified to have in addition to their angiogenic potential also osteogenic characteristics, leading to the hypothesis that bone regeneration could be stimulated by local administration of these cells. The aim of this study was to evaluate the angiogenic potential of locally administered progenitor cells to improve bone defect healing. Cells were separated from the peripheral blood of donor animals using the markers CD34 and CD133. Results of the in vitro experiments confirmed high angiogenic potential in the CD133(+) cell group. CD34(+) and CD133(+) cells were tested in an in vivo rat femoral defect model of delayed healing for their positive effect on the healing outcome. An increased callus formation and higher bone mineral density of callus tissue was found after the CD133(+) cell treatment compared to the group treated with CD34(+) cells and the control group without cells. Histological findings confirmed an increase in vessel formation and mineralization at day 42 in the osteotomy gap after CD133(+) cell transplantation. The higher angiogenic potential of CD133(+) cells from the in vitro experients therefore correlates with the in vivo data. This study demonstrates the suitability of angiogenic precursors to further bone healing and gives an indication that peripheral blood is a promising source for progenitor cells circumventing the problems associated with bone marrow extraction