Progressive changes of pre- and post-synaptic dopaminergic biomarkers in conscious MPTP-treated cynomolgus monkeys measured by positron emission tomography

Positron emission tomography (PET) is a useful technique for the consecutive investigation of the relationship between changes in neurotransmission biomarkers and behavioral signs in animal models of Parkinson's disease (PD). In this study, we aimed to investigate the threshold of dopamine (DA) neuron damage for the appearance of tremor by observing the longitudinal changes of pre- and post-synaptic DA biomarkers in awake monkeys using PET with multiple tracers. Three cynomolgus monkeys were treated with MPTP every 3-6 weeks until tremor was observed. Brain uptake of [11C]PE2I, [beta-11C]DOPA, and [11C]raclopride for DA transporter (DAT), DOPA utilization, and DA D2 receptor were measured using PET as a single set in awake condition. Sets of PET scans were repeated in parallel with continuous behavioral estimation. The pre-synaptic biomarkers of DA neuron in the striatum decreased [11C]PE2I binding and [beta-11C]DOPA uptake in an MPTP dose-dependent manner. Tremor was not observed until striatal [11C]PE2I binding was reduced to about 15% of the pretreatment level and [beta-11C]DOPA uptake was reduced to about 34%. DA D2 receptor measured by [11C]raclopride was not significantly changed throughout the experiment. Our results revealed that it is possible to quantitatively define the threshold of the onset of behavioral PD signs by monitoring spontaneous motor activity, and in vivo PET with DAT marker can be a biomarker for early diagnosis at the presymptomatic stage of PD and for high-risk groups.     

High plasma osteopontin levels in patients with inflammatory bowel disease

BACKGROUND: Osteopontin (OPN) plays a key role in the progression of T(H)1-immune-mediated disease in models of multiple sclerosis and rheumatoid arthritis. AIM: To determine whether plasma OPN levels in patients with inflammatory bowel disease are associated with disease activity. METHODS: Plasma samples were obtained from patients with ulcerative colitis (UC, n=30), Crohn's disease (CD, n=30), and healthy volunteers (controls, n=30) and enzyme immunoassay was performed. RESULTS: Plasma OPN concentrations were significantly higher in patients with Crohn's disease than in controls (951.9+/-538.5 ng/mL and 659.0+/-163.7 ng/mL, respectively). OPN concentrations in patients with UC were also higher than in the controls (1149.6+/-791.0 and 659.0+/-163.7, respectively). There was a significant difference in plasma OPN level between active UC and inactive UC (2102.0+/-552.8 and 649.4+/-313.0, respectively). Moreover, a significant correlation was observed between plasma OPN concentration and disease activity, as determined by the clinical activity index in patients with UC. CONCLUSIONS: Our results indicate that the plasma concentrations of OPN are elevated in patients with UC and that OPN expression is correlated with clinical activity. These results provide insight into UC pathogenesis and suggest that OPN may be a useful tool for assessing disease activity.     

A serious complication of a power injector for coronary angiography

The efficiency and safety of oleanolic acid (OA) and its isomer, ursolic acid (UA) in myocardial ischemia are poorly documented. This study appraised the efficacy of OA and UA in protecting the heart against oxidative damage induced by isoproterenol, since oxidative injury has been investigated as a potential initiator of myocardial necrosis. The level of TBARS increased whereas the antioxidants decreased significantly in the myocardium of ischemic animals. The levels were brought back to near normalcy in OA and UA pre-treated rats by scavenging the free radicals and blocking the induction of lipid peroxidation. These findings provide evidence that OA and UA protect rat myocardium against ischemic insult and the protective effect could be attributed to its antioxidant property and/or to a strengthening of myocardial membrane by its membrane stabilizing action. Among the two isomeric compounds, UA showed higher activity than OA.     

Serum vascular endothelial growth factor in cyanotic congenital heart disease functionally contributes to endothelial cell kinetics in vitro

BackgroundRemarkable amounts of neovascularization develop in patients with cyanotic congenital heart disease who have low pulmonary blood flow and systemic cyanosis, but the factors functionally responsible for angiogenesis in cyanotic congenital heart disease have not been determined.Methods and resultsTo investigate the functional angiogenic molecules in serum from these patients, serum angiogenic activity was studied in 21 patients (systemic oxygen saturation: 82 ± 1.9%) and in 17 healthy controls. Patient serum was more active in stimulating the tube formation of human umbilical vein endothelial cells (HUVECs) into capillary-like structures than control serum (150% vs 104% of internal control; p < 0.001). This increased serum angiogenic activity normalized after total cardiac repair (p < 0.001). The migration activity of HUVECs was also accelerated in patient serum (p = 0.007). To identify the molecules in patient serum affecting tube formation of HUVECs, we examined the effects of an inhibitor or a neutralizing antibody against various angiogenic molecules on in vitro angiogenesis. Both the soluble vascular endothelial growth factor (VEGF) receptor 1 and the VEGF receptor 2 tyrosine kinase inhibitor SU5416 reduced the basal serum angiogenic activity of patients and this was reversed by a supplement of recombinant human VEGF.ConclusionOur results indicate that serum VEGF functionally contributes to vascular endothelial cell kinetics in patients with cyanotic congenital heart disease.     

A case of pure red cell aplasia and systemic lupus erythematosus caused by human parvovirus B19 infection

Human parvovirus B19 (B19) rarely induces pure red cell aplasia (PRCA) in healthy hosts. Meanwhile B19 infection is often clinically similar to systemic lupus erythematosus (SLE), and several cases have been reported wherein B19 actually stimulated SLE exacerbation in an immunocompetent subject. An 82-year-old healthy woman was diagnosed to have complicated with B19 infection and PRCA. Four weeks later, she had high fever, polyarthritis, and oral ulcers, additionally diagnosed with SLE, and subsequently, 15 mg of prednisone was started. This is the first case wherein B19 infection caused both PRCA and SLE in a healthy patient as far as our investigations are concerned.     

Podocyte as the target for aldosterone: roles of oxidative stress and Sgk1

Accumulating evidence suggests that mineralocorticoid receptor blockade effectively reduces proteinuria in hypertensive patients. However, the mechanism of the antiproteinuric effect remains elusive. In this study, we investigated the effects of aldosterone on podocyte, a key player of the glomerular filtration barrier. Uninephrectomized rats were continuously infused with aldosterone and fed a high-salt diet. Aldosterone induced proteinuria progressively, associated with blood pressure elevation. Notably, gene expressions of podocyte-associated molecules nephrin and podocin were markedly decreased in aldosterone-infused rats at 2 weeks, with a gradual decrease thereafter. Immunohistochemical studies and electron microscopy confirmed the podocyte damage. Podocyte injury was accompanied by renal reduced nicotinamide-adenine dinucleotide phosphate oxidase activation, increased oxidative stress, and enhanced expression of aldosterone effector kinase Sgk1. Treatment with eplerenone, a selective aldosterone receptor blocker, almost completely prevented podocyte damage and proteinuria, with normalization of elevated reduced nicotinamide-adenine dinucleotide phosphate oxidase activity. In addition, proteinuria, podocyte damage, and Sgk1 upregulation were significantly alleviated by tempol, a membrane-permeable superoxide dismutase, suggesting the pathogenic role of oxidative stress. Although hydralazine treatment almost normalized blood pressure, it failed to improve proteinuria and podocyte damage. In cultured podocytes with consistent expression of mineralocorticoid receptor, aldosterone stimulated membrane translocation of reduced nicotinamide-adenine dinucleotide phosphate oxidase cytosolic components and oxidative stress generation in podocytes. Furthermore, aldosterone enhanced the expression of Sgk1, which was inhibited by mineralocorticoid receptor antagonist and tempol. In conclusion, podocytes are injured at the early stage in aldosterone-infused rats, resulting in the occurrence of proteinuria. Aldosterone can directly modulate podocyte function, possibly through the induction of oxidative stress and Sgk1.     

Pattern regulation in the stripe of zebrafish suggests an underlying dynamic and autonomous mechanism

The mechanism by which animal markings are formed is an intriguing problem that has remained unsolved for a long time. One of the most important questions is whether the positional information for the pattern formation is derived from a covert prepattern or an autonomous mechanism. In this study, using the zebrafish as the model system, we attempted to answer this classic question. We ablated the pigment cells in limited areas of zebrafish skin by using laser irradiation, and we observed the regeneration of the pigmentation pattern. Depending on the area ablated, different patterns regenerated in a specific time course. The regenerated patterns and the transition of the stripes during the regeneration process suggest that pattern formation is independent of the prepattern; furthermore, pattern formation occurs by an autonomous mechanism that satisfies the condition of "local self-enhancement and long-range inhibition." Because the zebrafish is the only striped animal for which detailed molecular genetic studies have been conducted, our finding will facilitate the identification of the molecular and cellular mechanisms that underlie skin pattern formation.     

Regulation of hypothalamic malonyl-CoA by central glucose and leptin

Hypothalamic malonyl-CoA has been shown to function in global energy homeostasis by modulating food intake and energy expenditure. Little is known, however, about the regulation of malonyl-CoA concentration in the central nervous system. To address this issue we investigated the response of putative intermediates in the malonyl-CoA pathway to metabolic and endocrine cues, notably those provoked by glucose and leptin. Hypothalamic malonyl-CoA rises in proportion to the carbohydrate content of the diet consumed after food deprivation. Malonyl-CoA concentration peaks 1 h after refeeding or after peripheral glucose administration. This response depends on the dose of glucose administered and is blocked by the i.c.v. administration of an inhibitor of glucose metabolism, 2-deoxyglucose (2-DG). The kinetics of change in hypothalamic malonyl-CoA after glucose administration is coincident with the suppression of phosphorylation of AMP kinase and acetyl-CoA carboxylase. Blockade of glucose utilization in the CNS by i.c.v. 2-DG prevented the effects of glucose on 5'AMP-activated protein kinase, malonyl-CoA, hypothalamic neuropeptide expression, and food intake. Finally, we showed that leptin can increase hypothalamic malonyl-CoA and that the increase is additive with glucose administration. Leptin-deficient ob/ob mice, however, showed no defect in the glucose- or refeeding-induced rise in hypothalamic malonyl-CoA after food deprivation, demonstrating that leptin was not required for this effect. These studies show that hypothalamic malonyl-CoA responds to the level of circulating glucose and leptin, both of which affect energy homeostasis.