Modulation of firing activity by ATP in dopamine neurons of the rat substantia nigra pars compacta

ATP acts as a neurotransmitter or co-neurotransmitter in many areas of the CNS and peripheral nervous systems; however, little is known about the expression and functional role of purinoceptors (P2) in midbrain dopaminergic neurons. Therefore, we investigated P2X receptor expression and regulation of spontaneous firing activity in dopaminergic neurons of the substantia nigra pars compacta (SNc) in rats using patch-clamp and Ca(2+)-imaging techniques. In most neurons, application of ATP (1 microM-1 mM) increased firing rate dose-dependently (EC(50)=1.26+/-0.26 microM, n=45). When the P2-receptor agonists such as 2-methylthio-adenosine 5'-triphosphate (2-MeSATP) or ATPgammaS were applied or pressure-applied to the neuron, the firing activity increased together with a rise in cytosolic Ca(2+) concentration ([Ca(2+)]c), but application of beta,gamma-methylene ATP (P2X(1, 3) agonist) or methylthio-adenosine 5'-diphosphate (P2Y(1) agonist) had no effect. In many neurons, the effect of ATP was abolished by the application of the P2-receptor antagonists, suramin or pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). When ATP was applied in a Ca(2+)-free solution, there was no detectable change in [Ca(2+)]c, suggesting that ATP does not release Ca(2+) from intracellular stores. In the single-cell reverse transcription polymerase chain reaction (RT-PCR), we found that 65% of dopaminergic neurons expressed mRNAs for P2X receptors; positive amplifications of P2X(6) (57.1%), P2X(2/6) (25.0%), and P2X(4) mRNA (17.9%), respectively. From the above results, we could conclude that ATP modulates firing activities in the rat SNc dopaminergic neurons, possibly via P2X(2), P2X(2/6), and/or P2X(4) receptors.

Non-invasive detection and monitoring of tumor pathological grade during neoadjuvant chemotherapy by measuring tissue water state using diffuse optical spectroscopic imaging

Abstract #803

Background: Changes of tissue water state are related to physiological and pathological properties of breast tissues. For instance, MRI has measured water mobility in order to monitor local micro-structural changes in breast cancer tissues during chemotherapy. Diffuse Optical Spectroscopic Imaging (DOSI) measures water molecular vibrational states associated with macro-molecular complexes in tissues such as proteins. For DOSI measurements, breast tumors are line-scanned and spectral information on each point is spatially mapped to generate an image.
 Subjects & Methods: DOSI was employed to measure 15 infiltrating ductal carcinoma (IDC) patients before treatment. Five IDC and one infiltrating lobular carcinoma (ILC) tumors were also measured along the course of neoadjuvant chemotherapy. Patient responses were determined from standard pathology: complete (N=2), partial (N=2) and non-responders (N=2). The spectral features of tissue water absorption from 935 nm to 998nm were compared to those of a pure water spectrum measured at body temperature in order to acquire the Bound Water Index (BWI: the residual between tissue and pure water spectra). In spectroscopic images, the Cancer BWI Ratio (CBR) was calculated by counting the fraction of the BWI less than 20% of the BWI range of pre-chemo (baseline) measurement in a primary cancer. Lower BWI means the cancer has more free water. The CBR communicates the changes of tissue water state along the course of therapies in the similar way to Signal Enhanced Ratio (SER) used in contrast enhanced MRI.
 Results: In our in vivo clinical studies with 15 IDC tumors, a high inverse correlation between BWI and Nottingham Bloom-Richardson histopathological score (R=-0.87) was found. In the neoadjuvant chemotherapy studies, BWI increased during the entire course of the therapy in complete responders while it fluctuated then stayed close to baseline values in partial responders. In non-responders, the change amount of BWI was very small and the BWI values decreased below baseline values. Quantitatively, for complete responders, BWI increased (more bound water) 59% from baseline and CBR decreased (less pixels for cancer) 26.9% and the pixels presenting cancer property disappeared. In partial responders, BWI increased 4.7% and CBR decreased 8.2% whereas, in non-responders, BWI decreased 16.4% and CBR increased 28.7%.
 Discussion: The high correlation between BWI and histopathological score communicates that water state measurements using DOSI report on disease grades of breast cancer non-invasively. In the neoadjuvant chemotherapy studies, bigger tissue water state changes have been measured in complete than partial responders and the changes to the opposite direction in non-responders. There results demonstrate a potential of tissue water state with DOSI as a non-invasive pathological grade monitor during chemotherapy, which can be used as a substitute for a biopsy at any point during the treatment cycle.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 803.

Hepatic inflammatory cytokine mRNA expression in hepatitis C virus-human immunodeficiency virus co-infection

Although epidemiologic studies have documented that hepatitis C virus (HCV)/human immunodeficiency virus (HIV) co-infected patients have accelerated fibrogenesis, especially those with CD4+ cell counts <200 cells/mm(3), the pathogenic mechanisms are poorly understood. We investigated whether severe immunodeficiency in co-infection is associated with changes in intrahepatic inflammatory cytokine mRNA levels. We measured interferon (IFN)-gamma, tumour necrosis factor-alpha, transforming growth factor (TGF)-beta(1), interleukin (IL)-4, IL-10, IL-12p35 and IL-12p40 mRNA levels by real-time PCR performed on liver samples from HCV mono-infected (n = 19) and HCV/HIV co-infected (n = 24) patients. Co-infected patients had decreased intrahepatic mRNA levels of IFN-gamma (P = 0.09), IL-4 (P = 0.05) and IL-12p35 (P = 0.04) compared with mono-infected patients, while IL-10 was increased (P = 0.07). In co-infected patients, IFN-gamma mRNA levels increased linearly with increasing peripheral CD4+ cell counts by 1.23 times relative to the calibrator for every 100 CD4+ cells/mm(3) increase (P = 0.02). No other cytokines were significantly associated with CD4+ cell counts. In conclusion, HIV-induced lymphopenia may result in hepatic inflammatory cytokine suppression in HCV/HIV co-infection. Intrahepatic IFN-gamma levels are significantly reduced in patients with advanced immunodeficiency. Further studies are needed to assess whether decreased IFN-gamma secretion by HCV-specific CD4+ cells may account for accelerated fibrogenesis in these patients.

[Arthroscopic reconstruction of the rotator cuff. The current gold standard?]

Arthroscopic rotator cuff repair has become the gold standard, and is now accepted throughout the world as the method of choice, for rotator cuff repair. As well as an experienced surgeon and meticulously correct arthroscopic technique, careful patient selection and adequate postoperative management are of decisive importance if a good postoperative outcome is to be achieved. With due consideration for all these factors the success rate is over 90%, as measured not only with reference to objective criteria, but also by patients' reports of their how satisfied they are with the result. This paper aims to report the indications, arthroscopic technique and postoperative protocol, and also the results of arthroscopic rotator cuff repair.

Orphan GPCR research

Orphan G protein-coupled receptors (GPCRs) are receptors lacking endogenous ligands. Found by molecular biological analyses, they became the roots of reverse pharmacology, in which receptors are attempted to be matched to potential transmitters. Later, when high-throughput screening technology was applied to reverse pharmacology, dozens of orphan GPCRs became deorphanized. Furthermore, novel neuropeptides were discovered. This review retraces the history of the orphan GPCRs and of the discoveries of their endogenous ligands, it also discusses the difficulties that the search for new ligands is presently encountering.

Channelling of dipolar molecules through carbon nanotubes

We study the dynamic polarization of carbon nanotubes caused by the propagation of fast electric dipoles under channelling conditions. We specifically analyse the position and orientation dependences of the dipole self-energy, stopping force, and the torque about the dipole centre. It is found that a dipole is strongly attracted to the nanotube wall and shows a tendency to orient itself perpendicular to the direction of motion. The stopping force shows more complex behaviour, but is generally found to be larger close to the nanotube wall and when oriented in the perpendicular direction at higher speeds.

Pharmacoproteomics: advancing the efficacy and safety of regenerative therapeutics

Proteomic analyses encompass a suite of high-throughput technologies for large-scale separation and identification of proteins responsible for execution of physiological processes. As such, proteomics is ideally suited to dissecting developmental complexity and dynamics, an understanding of which is vital to the realization of regenerative therapeutic medicine. Pharmacoproteomics is increasingly targeting characterization of regenerative therapeutic strategies. A perspective on the application of proteomics to further our understanding of cardiac regenerative medicine, in concert with guided cardiogenic programming, is delineated herein.

Effect of celecoxib on cyclooxygenase-2 expression and possible variants in a patient with Barrett's esophagus

Cyclooxygenase-2 (COX-2) expression is increased in metaplastic and dysplastic Barrett's esophageal epithelium and it is thought that selective COX-2 inhibitors could offer hope as chemoprevention therapy. The aim of the study was to investigate the in vivo effect of celecoxib on COX-2 expression in patients with Barrett's esophagus and no recent history of non-steroidal anti-inflammatory drug use. Endoscopic mucosal biopsy specimens were collected at baseline and after 28 days of therapy in a patient treated with celecoxib 200 mg twice daily. Samples were analyzed for COX-2 expression by immunoblot analysis with chemiluminescence detection. COX-2 expression was found to decline 20% and 44% at two different biopsy sites compared to the baseline sample. Longer exposures revealed a number of previously unidentified proteins above and below the 67 kDa COX-2 protein including 38 kDa and 45 kDa proteins which were present only at study completion consistent with up-regulation after celecoxib therapy. Further investigations of the 38 kDa and 45 kDa proteins were undertaken using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) with immunoblot and MALDI-TOF (matrix assisted laser desorption ionization - time of flight) analysis but no matches were found and results were inconclusive. Unmatched masses from MALDI-TOF peptide mass fingerprinting were compared with human COX-2 (67 kDa) and COX-2b (39 kDa) using unspecific cleavage. Peptide sequence homology with COX-2 and COX-2b was found for a length of 19 amino acids. Based on immunodetection, molecular weight and equivical MALDI-TOF results, one of these up-regulated proteins may be COX-2b.