Differentiation between solitary brain metastasis and high-grade glioma by diffusion tensor imaging

We tested our hypothesis that fractional anisotropy (FA) maps of diffusion tensor imaging could be used to differentiate between a solitary brain metastasis and a high-grade glioma. In seven patients with a solitary metastasis and seven patients with a high-grade glioma, FA values of enhancing and non-enhancing parts of the tumour were compared. Additionally, we visually assessed FA maps. No significant difference in the FA values of either the enhancing or non-enhancing part was found between the two groups. In the visual assessment, displacement of subcortical white-matter fibres was found in five of the seven metastasis patients, but in only one glioma patient. Additionally, discrimination between tumour and oedema was possible in three of the seven metastasis patients, but not in any glioma patient. Although FA values are not helpful in differentiating between the two groups, visual differences in FA values can allow the differentiation. Displacement of white-matter fibres is another finding suggestive of metastasis.     

Neurocutaneous melanosis associated with Hirschsprung's disease in a male neonate

Hirschsprung's disease is an inherited disorder characterized by the absence of ganglion cells in the distal bowel. Neurocutaneous melanosis is a rare congenital syndrome characterized by proliferation of melanin-producing cells in the skin and leptomeninges. The authors described a newborn patient with neurocutaneous melanosis associated with Hirschsprung's disease. This male baby had congenital hydrocephalus, large and multiple pigmented skin nevi, and severe abdominal distension. He showed marked hydrocephalus at birth and underwent a ventriculo-peritoneal shunt at the age of 5 days. Investigations for gut motility disorders revealed typical findings consistent with Hirschsprung's disease involving the rectosigmoid colon. He was surgically treated for Hirschsprung's disease after transanal endorectal pull-through at the age of 7 months. After settlement of the ventriculo-peritoneal shunt, the transanal approach was of significant value for keeping the intraperitoneal catheter clean. The association of developmental disorders of melanocytes and enteric ganglia, both of which originated from the neural crest, suggested the presence of mutual pathogenetic factors in the patient.     

Quantitative analysis of distribution and fate of human lung cancer emboli labeled with 125I-5-iodo-2′-deoxyuridine in nude mice

The chemical and radio toxicity of ¹²⁵-5-iodo-2-deoxyuridine (¹²⁵IUDR) on 870127T human lung cancer (HLC) cells grown in tissue cultures and the quantitative analysis of the distribution and fate of ¹²⁵IUDR-labeled 870127T HLC cells in nude mice were evaluated. After 870127T HLC cells were plated and ¹²⁵IUDR was added to the dishes at levels ranging from 0.1 µCi/ml to 5.0 µCi/ml of media, the growth rate of the cells for 24h was similar to that of non-labeled cells. Nude mice were given intravenous injections of ¹²⁵IUDR labeled 870127T HLC cells and killed at various intervals ranging from 5 min to 24 h after injection. Organs were collected, processed, and monitored. The lung contained most of the tumor cells at all intervals and the number of tumor cells in the lung decreased gradually post-injection. The tumor cells died rapidly, and only about 1.5% of all cell survived after 24 h post-injection. This study confirmed that very few surviving tumor cells are needed to cause metastasis.     

Inhibitory effects of an orexin-2 receptor antagonist on orexin A- and stress-induced ACTH responses in conscious rats

Orexins, recognized for their diverse functions in sleep/wakefulness/arousal and appetite regulation, may play provocative roles in stress response. Although the PVN of the hypothalamus expresses an abundance of orexin-2 receptor (OX-2R), the involvement of OX-2R in regulating ACTH response to stress remains unclear. To address this, we examined effects of a selective antagonist to OX-2R (N-{(1S)-1-[6,7-dimethoxy-3,4-dihydro-2(1H)-isoquinolinyl]carbonyl}-2,2-dimethylpropyl)-N-{4-pyridinylmethyl}amine upon plasma ACTH concentrations after administration of orexin A and swimming stress. Increases in ACTH levels with orexin A or swimming stress were attenuated with prior administration of an OX-2R antagonist. These results suggest that swimming stress facilitates ACTH release, at least in part via activation of OX-2R.     

Ghrelin improves renal function in mice with ischemic acute renal failure

Growth hormone and IGF-1 have been suggested to have tissue-protective effects. Ghrelin is a stomach-derived growth hormone secretagogue. The effects of ghrelin on ischemia/reperfusion-induced renal failure in mice were examined. Ischemic acute renal failure was induced by bilateral renal artery clamping for 45 min and reperfusion for 24 h. Ghrelin (100 microg/kg mouse) or vehicle was injected subcutaneously six times before surgery and three times after surgery every 8 h. Twenty-four hours after reperfusion, the right kidney was isolated and perfused. Acetylcholine (ACh)- and adrenomedullin-induced endothelium-dependent vasorelaxation of renal vessels significantly improved in ghrelin-pretreated mice (%Delta renal perfusion pressure by 10(-7) M ACh -63.5 +/- 3.7 versus -41.2 +/- 5.5%; P < 0.05). This change was associated with significant increases of nitric oxide release in the kidneys of ghrelin-treated mice (10(-7) M ACh 35.5 +/- 5.8 versus 16.9 +/- 3.5 fmol/g kidney per min; P < 0.05). Serum concentration of urea nitrogen (53 +/- 7 versus 87 +/- 15 mg/dl; P < 0.05) and renal injury score were significantly lower in the ghrelin group (2.5 +/- 0.8 versus 5.3 +/- 1.5; P < 0.01). Tubular apoptotic index was significantly lower in the ghrelin group (5 +/- 5 versus 28 +/- 4; P < 0.05). Furthermore, the survival rate after the 60-min ischemic period was higher in the ghrelin group (80 versus 20%; P < 0.05). Ghrelin treatment significantly increased the serum level of IGF-1. However, such renal protective effects of ghrelin on ischemia/reperfusion injury were not observed in insulin receptor substrate-2 knockout mice. These results suggest that ghrelin may protect the kidneys from ischemia/reperfusion injury and that this effect is related to an improvement of endothelial function through an IGF-1-mediated pathway.     

Identification of a novel 4-aminomethylpiperidine class of M3 muscarinic receptor antagonists and structural insight into their M3 selectivity

Identification of a novel class of potent and highly selective M(3) muscarinic antagonists is described. First, the structure-activity relationship in the cationic amine core of our previously reported triphenylpropionamide class of M(3) selective antagonists was explored by a small diamine library constructed in solid phase. This led to the identification of M(3) antagonists with a novel piperidine pharmacophore and significantly improved subtype selectivity from a previously reported class. Successive modification on the terminal triphenylpropionamide part of the newly identified class gave 14a as a potent M(3) selective antagonist that had >100-fold selectivity versus the M(1), M(2), M(4), and M(5) receptors (M(3): K(i) = 0.30 nM, M(1)/M(3) = 570-fold, M(2)/M(3) = 1600-fold, M(4)/M(3) = 140-fold, M(5)/M(3) = 12000-fold). The possible rationale for its extraordinarily higher subtype selectivity than reported M(3) antagonists was hypothesized by sequence alignment of multiple muscarinic receptors and a computational docking of 14a into transmembrane domains of M(3) receptors.     

An ITAM-signaling pathway controls cross-presentation of particulate but not soluble antigens in dendritic cells

Dendritic cells (DC) possess a unique capacity for presenting exogenous antigen on major histocompatibility class I, a process that is referred to as cross-presentation, which serves a critical role in microbial and tumor immunity. During cross-presentation, antigens derived from pathogen-infected or tumor cells are internalized and processed by DCs for presentation to cytotoxic T lymphocytes (CTLs). We demonstrate that a signaling pathway initiated by the immunoreceptor tyrosine-based activation motif (ITAM)-containing adaptors DAP12 and FcRgamma utilizes the Vav family of Rho guanine nucleotide exchange factors (GEFs) for processing and cross-presentation of particulate, but not soluble, antigens by DCs. Notably, this novel pathway is crucial for processing and presentation of particulate antigens, such as those associated with Listeria monocytogenes bacteria, yet it is not required for antigen uptake. Mechanistically, we provide evidence that in DCs, Vav GEFs are essential to link ITAM-dependent receptors with the activation of the NOX2 complex and production of reactive oxygen species (ROS), which regulate phagosomal pH and processing of particulate antigens for cross-presentation. Importantly, we show that genetic disruption of the DAP12/FcRgamma-Vav pathway leads to antigen presentation defects that are more profound than in DCs lacking NOX2, suggesting that ITAM signaling also controls cross-presentation in a ROS-independent manner.