Background Gastrin/cholecystokinin type B receptors (CCKBRs) can be found on parietal cells and smooth muscle cells and are the predominant brain CCK receptors. Recent cloning studies indicate that this receptor type might also be expressed in the kidney. Materials and methods We used Northern blot analysis in guinea pig. kidney and reverse transcriptase polymerase chain reaction (RT‐PCR) in several murine kidney cell lines to evaluate this organ for the expression of the CCKBRs. The receptor was pharmacologically characterized by displacement experiments using [125I]‐BH‐CCKs and various agonists and antagonists. Polyclonal antibodies vs. the CCKBRs were raised in chicken, and immunohistochemistry on tissue sections was used to localize the receptor within the organ. The effect of gastrin on renal cell growth was measured using proximal tubulus (MCT) cells, which were cultured with gastrin (10−9 M) for 24–72 h. Cell counts and [3H]‐thymidine incorporation experiments were performed. Results CCKBR transcripts can be detected in kidney RNA (tubules > glomeruli > interstitium). RT‐PCR revealed CCKBR transcripts in proximal tubules (MCT cells) and in mesangium (MMC). The medullary thick ascending limb of Henle's loop and several control tissues such as liver and muscle were negative. Displacement experiments using [125I]‐BH‐CCK and various agonists and antagonists identified binding sites with typical CCKBR pharmacology. CCKBRs were localized in the proximal tubulus, distal collecting ducts and mesangium cells. Treatment of rested MCT cells with gastrin 17‐1 induced cell proliferation and [3H]‐thymidine incorporation by at least 40% compared with normal growth (P < 0.05). Conclusion These results show for the first time that CCKBRs are present in selected areas of the kidney, and strongly confirm our previous observation that this organ expresses binding sites for [125I]‐gastrin. Furthermore, gastrin might act as a growth factor in the kidney.
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A compact laser spectrometer for the detection of explosives from a safe spot is presented. This laser setup also opens the possibility for the trace detection of explosives.Laser-Stand-off technology for remote detection of explosives and their traces on contaminated surfaces is a field of research that has recently gained much interest. In this report, to our knowledge for the first time, a remote compact stand-off detection system is presented that uses pulsed mid infrared laser absorption spectroscopy, if necessary in combination with pulsed laser fragmentation (PLF). A compact fiber coupled system is developed in the so called "eye-safe" region. Here we introduce a compact fiber coupled sensor containing a fiber amplifier for the fragmentation and a Quantum Cascade Laser (QCL) operating in the mid-infrared for the absorption spectroscopy of the product gases from different traces of explosives like TNT and HMX. Figure 1 shows a typical absorption spectrum of nitric oxide (NO) produced by photo fragmentation of HMX. Fig. 1: NO spectrum after PLF of HMX.Experimental investigations indicate that the absorption of explosives is more efficient in the "eye-safe" spectral range around 1.5 μm rather than for the conventionally used fundamental Nd:YAG line at 1.06 μm [1]. In order to optimize laser material interaction with a compact setup a laser excitation in the "eye-safe" region is done by an Er:Yb co-doped fiber-amplifier. In our setup an Er:Yb-doped glass passively Q-switched diode-pumped solid state laser (DPSSL) emitting around 1535 nm is amplified by an Erbium-Ytterbium co-doped large mode area fiber and generates pulses with energies up to E P = 200 μJ at a high repetition rate in the kHz regime. QCLs at different operating wavelengths are tested in cw-mode and in pulsed mode for best performance for the detection of hazardous materials. First results for the detection of TATP which is present in the gas phase without pre-treatment are also discussed.[1] C.Bauer, P.Geiser, J.Burgmeier, G.Holl and W.Schade, "Pulsed laser surface fragmentation and mid-infrared laser spectroscopy for remote detetction of explosives", Applied Physics B 85, 251-256 (2006).
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