A new apparatus for standardized rat kidney biopsy.

Survival biopsies are frequently applied in rat kidney disease models, but several drawbacks such as surgical kidney trauma, bleeding risk and variable loss of kidney tissue are still unsolved. Therefore, we developed an easy-to-use core biopsy instrument and evaluated whether two consecutive kidney biopsies within the same kidney can be carried out in a standardized manner. On day 0, 18 Lewis rats underwent a right nephrectomy and 9 of these rats a subsequent first biopsy of the left kidney (Bx group). 9 control rats had a sham biopsy of the left kidney (Ctrl group). On day 7, a second kidney biopsy/sham biopsy was performed. On day 42, all animals were sacrificed and their kidneys were removed for histology. Biopsy cylinders contained 57±28 glomeruli per transversal section, representing an adequate sample size. PAS staining showed that the biopsy depth was limited to the renal cortex whereas surgical tissue damage was limited to the area immediately adjacent to the taken biopsy cylinder. On day 42, the reduction of functional renal mass after two biopsies was only 5.2% and no differences of body weight, blood pressure, proteinuria, serum creatinine, glomerulosclerosis, interstitial fibrosis or number of ED-1 positive macrophages were found between both groups. In summary, our apparatus offers a safe method to perform repetitive kidney biopsies with minimal trauma and sufficient sample size and quality even in experimental disease models restricted to one single kidney

Experimental set-up.

<p><b>Day 0</b>: Right nephrectomy in both groups. Subsequent biopsy of the upper pole of the residual kidney in the Bx group and sham biopsy of the residual kidney in the control group. <b>Day 7</b>: Biopsy of the lower kidney pole in the Bx group and second sham biopsy in the control group. <b>Day 42</b>: Animals were sacrificed and kidneys were removed for histology. Body weight, blood pressure, proteinuria and serum creatinine were measured before operations on day 0 and day 42 in both groups (*).</p

Comparison of the biopsy group with the control group on day 42^*.

<p>*Values are expressed as mean ±SD. Bx, biopsy group; Ctrl, control group; Body Wt, body weight; BP, blood pressure; Protein, proteinuria; SCr, serum creatinine; GS score, glomerulosclerosis score (see methods); IF score, interstitial fibrosis score (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115368#s2" target="_blank">methods</a>); Glom ED-1, number of glomerular ED-1 positive macrophages/50 glomeruli; Inter ED-1, number of interstitial ED-1 positive macrophages/mm²; n.a., not applicable. Statistical significance was defined as <i>P</i><0.05.</p><p>Comparison of the biopsy group with the control group on day 42^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115368#nt101" target="_blank">*</a>}.</p

Technical drawing and operational principle of the new biopsy apparatus.

<p><b>A</b>: Longitudinal section. The sleight (in white) and the helve (in dark grey) interact by a slot and key linkage where the tongue of the sleight being located inside snaps into the circular grooves of the helve (arrowheads). <b>B and C</b>: Operational steps 1–3. The cutting filament around the circular blade forms the reference point for the stitch depth (*).</p

Meteorology and oceanography of the Atlantic sector of the Southern Ocean—a review of German achievements from the last decade

In the early 1980s, Germany started a new era of modern Antarctic research. The Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) was founded and important research platforms such as the German permanent station in Antarctica, today called Neumayer III, and the research icebreaker Polarstern were installed. The research primarily focused on the Atlantic sector of the Southern Ocean. In parallel, the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) started a priority program ‘Antarctic Research’ (since 2003 called SPP-1158) to foster and intensify the cooperation between scientists from different German universities and the AWI as well as other institutes involved in polar research. Here, we review the main findings in meteorology and oceanography of the last decade, funded by the priority program. The paper presents field observations and modelling efforts, extending from the stratosphere to the deep ocean. The research spans a large range of temporal and spatial scales, including the interaction of both climate components. In particular, radiative processes, the interaction of the changing ozone layer with large-scale atmospheric circulations, and changes in the sea ice cover are discussed. Climate and weather forecast models provide an insight into the water cycle and the climate change signals associated with synoptic cyclones. Investigations of the atmospheric boundary layer focus on the interaction between atmosphere, sea ice and ocean in the vicinity of polynyas and leads. The chapters dedicated to polar oceanography review the interaction between the ocean and ice shelves with regard to the freshwater input and discuss the changes in water mass characteristics, ventilation and formation rates, crucial for the deepest limb of the global, climate-relevant meridional overturning circulation. They also highlight the associated storage of anthropogenic carbon as well as the cycling of carbon, nutrients and trace metals in the ocean with special emphasis on the Weddell Sea