Magnetization exchange observed in human skeletal muscle by non-water-suppressed proton magnetic resonance spectroscopy

Many metabolites in the proton magnetic resonance spectrum undergo magnetization exchange with water, such as those in the downfield region (6.0-8.5 ppm) and the upfield peaks of creatine, which can be measured to reveal additional information about the molecular environment. In addition, these resonances are attenuated by conventional water suppression techniques complicating detection and quantification. To characterize these metabolites in human skeletal muscle in vivo at 3 T, metabolite cycled non-water-suppressed spectroscopy was used to conduct a water inversion transfer experiment in both the soleus and tibialis anterior muscles. Resulting median exchange-independent T(1) times for the creatine methylene resonances were 1.26 and 1.15 s, and for the methyl resonances were 1.57 and 1.74 s, for soleus and tibialis anterior muscles, respectively. Magnetization transfer rates from water to the creatine methylene resonances were 0.56 and 0.28 s(-1) , and for the methyl resonances were 0.39 and 0.30 s(-1) , with the soleus exhibiting faster transfer rates for both resonances, allowing speculation about possible influences of either muscle fibre orientation or muscle composition on the magnetization transfer process. These water magnetization transfer rates observed without water suppression are in good agreement with earlier reports that used either postexcitation water suppression in rats, or short CHESS sequences in human brain and skeletal muscle.

Effects of a non-selective COX inhibitor and selective COX-2 inhibitors on contractility of human and porcine ureters in vitro and in vivo

BACKGROUND AND PURPOSE: Anti-inflammatory drugs are used in the treatment of acute renal colic. The aim of this study was to investigate the effects of selective COX-2 inhibitors and the non-selective COX inhibitor diclofenac on contractility of human and porcine ureters in vitro and in vivo, respectively. COX-1 and COX-2 receptors were identified in human ureter and kidney. EXPERIMENTAL APPROACH: Human ureter samples were used alongside an in vivo pig model with or without partial ureteral obstruction. COX-1 and COX-2 receptors were located in human ureters by immunohistochemistry. KEY RESULTS: Diclofenac and valdecoxib significantly decreased the amplitude of electrically-stimulated contractions in human ureters in vitro, the maximal effect (Vmax) being 120 and 14%, respectively. Valdecoxib was more potent in proximal specimens of human ureter (EC50=7.3 x 10(-11) M) than in distal specimens (EC50=7.4 x 10(-10) M), and the Vmax was more marked in distal specimens (22.5%) than in proximal specimens (8.0%) in vitro. In the in vivo pig model, parecoxib, when compared to the effect of its solvent, significantly decreased the maximal amplitude of contractions (Amax) in non-obstructed ureters but not in obstructed ureters. Diclofenac had no effect on spontaneous contractions of porcine ureter in vivo. COX-1 and COX-2 receptors were found to be expressed in proximal and distal human ureter and in tubulus epithelia of the kidney. CONCLUSIONS AND IMPLICATIONS: Selective COX-2 inhibitors decrease the contractility of non-obstructed, but not obstructed, ureters of the pig in vivo, but have a minimal effect on electrically-induced contractions of human ureters in vitro.

OCT4 expression in human non-small cell lung cancer: implications for therapeutic intervention

Here we investigate the expression of OCT4 human lung adenocarcinoma and bronchioloalveolar carcinoma (BAC) tumor biopsies and tumor-derived primary cell cultures. OCT4 has been detected in several human tumors suggesting a potentially critical role in tumorigenesis. We assessed the presence of OCT4 in clinical tumor samples of both adenocarcinoma and BAC at the cellular and transcriptional levels, respectively. Furthermore, we evaluated tumor-derived cell cultures for potential differences in OCT4 expression. Immunohistochemical analysis depicted OCT4 in 2 of 8 adenocarcinoma tumor samples and 3 of 5 BAC tumor samples, with no apparent difference in the degree of expression among the sections examined. These results were validated by transcript analysis. Flow cytometric assessment of 11 adenocarcinoma-derived cell cultures and 3 BAC-derived cell cultures revealed significantly higher OCT4 expression in adenocarcinoma tumors compared to their normal counterparts. This, however, was not observed in the BAC cultures. Comparative studies of OCT4 in adenocarcinoma and BAC tumor cell cultures demonstrated a dramatically higher expression in the former. The expression of OCT4 may represent a specific and effective target for therapeutic intervention in adenocarcinoma and BAC. In addition, the aberrant expression and distribution of OCT4 may indicate important parameters concerning the differences between adenocarcinoma and BAC.

Normal human serum contains high levels of anti-Gal alpha 1-4GlcNAc antibodies

BACKGROUND: Natural xenoreactive antibodies (Abs) directed against the Bdi-epitope (Gal alpha 1-3Gal beta) on the cells of non-primate mammals take part in hyperacute rejection of xenotransplanted organs. We found that some Abs, which were one-step affinity purified on Bdi-Sepharose, cross-reacted with the disaccharide Gal alpha 1-4GlcNAc beta. The epitope Gal alpha 1-4GlcNAc has not been identified on mammals or bacterial polysaccharides yet. METHODS: To isolate the antibodies of the corresponding specificity the disaccharide was immobilized on Sepharose and antibodies were affinity purified from pooled serum of blood group O individuals. RESULTS: These one-step purified Abs cross-reacted with Bdi, but after a prior absorption step on Bdi-Sepharose no cross-reactivity with Bdi was observed any longer. Surprisingly, the quantity of anti-Gal alpha 1-4GlcNAc isolated from the same serum pool, 4-7 microg/ml, was equal to that of anti-Bdi or more. Independently of ABO blood groups all the tested healthy donors had anti-Gal alpha 1-4GlcNAc Abs at a similar level. Monospecific anti-Gal alpha 1-4GlcNAc Abs were not cytotoxic towards porcine cells. CONCLUSIONS: 1. The actual concentration of monospecific, xenoreactive Gal alpha 1-3Gal beta Abs in blood may be considerably lower than the value referred to in the literature for 'anti-alpha Gal' or 'anti-Galili' antibodies. 2. Anti-Gal alpha 1-4GlcNAc Abs seem not to be important for xenotransplantation.

Metabolomic tissue signature in human non-alcoholic fatty liver disease identifies protective candidate metabolites

Background Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder in industrialized countries, yet its pathophysiology is incompletely understood. Small-molecule metabolite screens may offer new insights into disease mechanisms and reveal new treatment targets. Methods Discovery (N = 33) and replication (N = 66) of liver biopsies spanning the range from normal liver histology to non-alcoholic steatohepatitis (NASH) were ascertained ensuring rapid freezing under 30 s in patients. 252 metabolites were assessed using GC/MS. Replicated metabolites were evaluated in a murine high-fat diet model of NAFLD. Results In a two-stage metabolic screening, hydroquinone (HQ, pcombined = 3.0 × 10−4) and nicotinic acid (NA, pcombined = 3.9 × 10−9) were inversely correlated with histological NAFLD severity. A murine high-fat diet model of NAFLD demonstrated a protective effect of these two substances against NAFLD: Supplementation with 1% HQ reduced only liver steatosis, whereas 0.6% NA reduced both liver fat content and serum transaminase levels and induced a complex regulatory network of genes linked to NALFD pathogenesis in a global expression pathway analysis. Human nutritional intake of NA equivalent was also consistent with a protective effect of NA against NASH progression. Conclusion This first small-molecular screen of human liver tissue identified two replicated protective metabolites. Either the use of NA or targeting its regulatory pathways might be explored to treat or prevent human NAFLD.

Image registration for triggered and non-triggered DTI of the human kidney: Reduced variability of diffusion parameter estimation

BACKGROUND: To investigate if non-rigid image-registration reduces motion artifacts in triggered and non-triggered diffusion tensor imaging (DTI) of native kidneys. A secondary aim was to determine, if improvements through registration allow for omitting respiratory-triggering. METHODS: Twenty volunteers underwent coronal DTI of the kidneys with nine b-values (10-700 s/mm2 ) at 3 Tesla. Image-registration was performed using a multimodal nonrigid registration algorithm. Data processing yielded the apparent diffusion coefficient (ADC), the contribution of perfusion (FP ), and the fractional anisotropy (FA). For comparison of the data stability, the root mean square error (RMSE) of the fitting and the standard deviations within the regions of interest (SDROI ) were evaluated. RESULTS: RMSEs decreased significantly after registration for triggered and also for non-triggered scans (P < 0.05). SDROI for ADC, FA, and FP were significantly lower after registration in both medulla and cortex of triggered scans (P < 0.01). Similarly the SDROI of FA and FP decreased significantly in non-triggered scans after registration (P < 0.05). RMSEs were significantly lower in triggered than in non-triggered scans, both with and without registration (P < 0.05). CONCLUSION: Respiratory motion correction by registration of individual echo-planar images leads to clearly reduced signal variations in renal DTI for both triggered and particularly non-triggered scans. Secondarily, the results suggest that respiratory-triggering still seems advantageous.J. Magn. Reson. Imaging 2014. (c) 2014 Wiley Periodicals, Inc.

Porcine extrahepatic vascular endothelial asialoglycoprotein receptor 1 mediates xenogeneic platelet phagocytosis in vitro and in human-to-pig ex vivo xenoperfusion.

BACKGROUND Asialoglycoprotein receptor-1 (ASGR1) mediates capture and phagocytosis of platelets in pig-to-primate liver xenotransplantation. However, thrombocytopenia is also observed in xenotransplantation or xenoperfusion of other porcine organs than liver. We therefore assessed ASGR1 expression as well as ASGR1-mediated xenogeneic platelet phagocytosis in vitro and ex vivo on porcine aortic, femoral arterial, and liver sinusoidal endothelial cells (PAEC/PFAEC/PLSEC). METHODS Porcine forelimbs were perfused with whole, heparinized human or autologous pig blood. Platelets were counted at regular intervals. Pig limb muscle and liver, as well as PAEC/PFAEC/PLSEC, were characterized for ASGR1 expression. In vitro, PAEC cultured on microcarrier beads and incubated with non-anticoagulated human blood were used to study binding of human platelets and platelet-white blood cell aggregation. Carboxyfluorescein diacetate succinimidyl ester-labeled human platelets were exposed to PAEC/PFAEC/PLSEC and analyzed for ASGR1-mediated phagocytosis. RESULTS Human platelet numbers decreased from 102 ± 33 at beginning to 13 ± 6 × 10/μL (P < 0.0001) after 10 minutes of perfusion, whereas no significant decrease of platelets was seen during autologous perfusions (171 ± 26 to 122 ± 95 × 10/μL). The PAEC, PFAEC, and PLSEC all showed similar ASGR1 expression. In vitro, no correlation was found between reduction in platelet count and platelet-white blood cell aggregation. Phagocytosis of human carboxyfluorescein diacetate succinimidyl ester-labeled platelets by PAEC/PFAEC/PLSEC peaked at 15 minutes and was inhibited (P < 0.05 to P < 0.0001) by rabbit anti-ASGR1 antibody and asialofetuin. CONCLUSIONS The ASGR1 expressed on aortic and limb arterial pig vascular endothelium plays a role in binding and phagocytosis of human platelets. Therefore, ASGR1 may represent a novel therapeutic target to overcome thrombocytopenia associated with vascularized pig-to-primate xenotransplantation.