T2 relaxation times of 13C metabolites in a rat hepatocellular carcinoma model measured in vivo using 13C‐MRS of hyperpolarized [1‐13C]pyruvate

A single‐voxel Carr‐Purcell‐Meibloom‐Gill sequence was developed to measure localized T₂ relaxation times of ¹³C‐labeled metabolites in vivo for the first time. Following hyperpolarized [1‐¹³C]pyruvate injections, pyruvate and its metabolic products, alanine and lactate, were observed in the liver of five rats with hepatocellular carcinoma and five healthy control rats. The T₂ relaxation times of alanine and lactate were both significantly longer in HCC tumors than in normal livers (p < 0.002). The HCC tumors also showed significantly higher alanine signal relative to the total ¹³C signal than normal livers (p < 0.006). The intra‐ and inter‐subject variations of the alanine T₂ relaxation time were 11% and 13%, respectively. The intra‐ and inter‐subject variations of the lactate T₂ relaxation time were 6% and 7%, respectively. The intra‐subject variability of alanine to total carbon ratio was 16% and the inter‐subject variability 28%. The intra‐subject variability of lactate to total carbon ratio was 14% and the inter‐subject variability 20%. The study results show that the signal level and relaxivity of [1‐¹³C]alanine may be promising biomarkers for HCC tumors. Its diagnostic values in HCC staging and treatment monitoring are yet to be explored. Copyright © 2010 John Wiley & Sons, Ltd.     

Lipopolysaccharide-Activated Macrophages Stimulate the Synthesis of Collagen Type I and C-Fibronectin in Cultured Pancreatic Stellate Cells

We have recently identified and characterized pancreatic stellate cells (PSC) in rats and humans (Gastroenterology 1998, 15:421-435). PSC are suggested to represent the main cellular source of extracellular matrix in chronic pancreatitis. Now we describe a paracrine stimulatory loop between human macrophages and PSC (rat and human) that results in an increased extracellular matrix synthesis. Native and transiently acidified supernatants of cultured macrophages were added to cultured PSC in the presence of 0.1% fetal calf serum. Native supernatants of lipopolysaccharide-activated macrophages stimulated the synthesis of collagen type I 1.38 +/- 0.09-fold of control and c-fibronectin 1.89 +/- 0.18-fold of control. Transiently acidified supernatants stimulated collagen type I and c-fibronectin 2.10 +/- 0.2-fold and 2.80 +/- 0.05-fold of control, respectively. Northern blot demonstrated an increased expression of the collagen-I-(alpha-1)-mRNA and fibronectin-mRNA in PSC 10 hours after addition of the acidified macrophage supernatants. Cell proliferation measured by bromodeoxyuridine incorporation was not influenced by the macrophage supernatants. Unstimulated macrophages released 1.97 pg TGFbeta1/microgram of DNA over 24 hours and lipopolysaccharide-activated macrophages released 6.61pg TGFbeta1/microgram of DNA over 24 hours. These data together with the results that, in particular, transiently acidified macrophage supernatants increased matrix synthesis, identify TGFbeta as the responsible mediator. In conclusion, our data demonstrate a paracrine stimulation of matrix synthesis of pancreatic stellate cells via TGFbeta1 released by activated macrophages. We suggest that macrophages might play a pivotal role in the development of pancreas fibrosis.     

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Ohne Zusammenfassung     

Allergy in bakers’ apprentices and factors associated to non-participation in a cohort study of allergic sensitization

Objective To describe the prevalence of atopy and respiratory symptoms among baker apprentices at the start of the education and factors associated with non-participation in the study. Methods A total of 346 students, 22.1(0.6) years of age, mean (SD), from the food production programme of technical colleges in Denmark were invited to participate in a 3 year study. Of the students, 187 agreed to participate and filled in a physician-administered questionnaire. The presence of atopy was determined by skin prick test (SPT) and serum allergen specific IgE (SpIgE). Bronchial hyper responsiveness to methacholine (PD₂₀ ≤ 1,440 μg) was determined. Results Prevalence of atopy was 32%. The prevalence of symptoms from the lungs and nose was 19.8 and 25.5%, respectively. Significantly, more SPT reactions were seen in males compared to females (39 vs. 22%, P < 0.05). Sensitization towards flour was significantly more frequent if determined as SpIgE (7.3%) compared to SPT (0.5%). We found a positive association between atopy and lung symptoms OR 6.1 (2.8–13.2 SD) and nasal symptoms OR 3.7 (1.8–7.5 SD). The major reason for non-participation was fear of blood sampling (25.5%). Conclusion The prevalence of atopy in bakers’ apprentices was of the same magnitude in the general Danish population. Significantly, more male bakers’ apprentices had atopy. This finding has major impact on the diagnostic procedures of occupational allergy in bakery workers emphasizing the need for standardization of the clinical tests. The main reasons for non-participation were, fear of blood-sampling (57%) and the 3 years commitment to the follow-up study (39%).     

Poor diagnostic value of colonic CD44v6 expression and serum concentrations of its soluble form in the differentiation of ulcerative colitis from Crohn's disease

Background—Increased expression ofCD44v6 on colonic crypt epithelial cells in ulcerative colitis has beensuggested as a diagnostic tool to distinguish ulcerative colitis fromcolonic Crohn's disease.
Aims—To investigate colonicCD44v6 expression and serum concentrations of soluble CD44v6 (sCD44v6)in patients with ulcerative colitis and Crohn's disease.
Methods—Colonic biopsy samples wereobtained from 16 patients with ulcerative colitis, 13 with ileocolonicCrohn's disease, and 10 undergoing polypectomy. Serum samples wereobtained from 15 patients with active ulcerative colitis, 20 withactive Crohn's disease, and 20 healthy donors. Colonic CD44v6expression was evaluated immunohistochemically by monoclonal antibody2F10 and the higher affinity monoclonal antibody VFF18. Serum sCD44v6concentrations were measured by ELISA.
Results—2F10 stained colonicepithelium of inflamed ulcerative colitis and Crohn's disease samplesin 80% and 40% of cases, respectively, and VFF18 in 95% and 87%,respectively. Both monoclonal antibodies displayed a sensitivity andspecificity of 60% and 87% to differentiate ulcerative colitis fromcolonic Crohn's disease. Serum concentrations of sCD44v6 were lower inpatients with ulcerative colitis (median 153 ng/ml; interquartile range(IQR) 122-211) compared with Crohn's disease (219; IQR 180-243) andhealthy donors (221; IQR 197-241 (p=0.002)). Its sensitivity andspecificity to discriminate ulcerative colitis from Crohn's diseasewas 75% and 71%, respectively.
Conclusion—Colonic CD44v6 and serumsCD44v6 concentrations do not facilitate reliable differentialdiagnosis between ulcerative colitis and Crohn's disease.

Keywords:CD44 variant 6; differential diagnosis; immunohistochemistry; soluble CD44v6

     

Anterior Hippocampal Volume Deficits in Nonamnesic, Aging Chronic Alcoholics

Magnetic resonance imaging was used to quantify the volume of the hippocampus in 47 men with chronic alcoholism and 72 healthy male control subjects. The subjects ranged in age from 21 to 70 years, thus permitting a test of whether older alcoholics suffer greater brain tissue volume reduction than do younger ones. Comparison brain regions included temporal lobe gray matter, white matter, and cerebrospinal fluid, as well as measures of the lateral ventricles, third ventricle, and temporal horns. The results of this cross-sectional study showed that the anterior, but not the posterior, portions of the hippocampus in both hemispheres were significantly smaller in the alcoholic than the healthy control group. Furthermore, the bilateral anterior hippocampal volume loss was greater in older than younger alcoholics. Despite the hippocampal volume deficit, these alcoholics did not demonstrate an explicit memory impairment; furthermore, memory test scores did not correlate significantly with hippocampal volumes. In the alcoholics, the age-related volume loss, which was over and above that expected in normal aging, was also evident in the temporal cortex and white matter. Likewise, alcoholic ventricular enlargement was age-related. Analysis of covariance revealed that the anterior hippocampal deficit persisted after accounting for the temporal lobe gray matter volume deficit. Multiple regression analysis revealed that the age-related brain volume abnormalities observed in the alcoholics could not be attributed to duration of alcoholism or total lifetime consumption of alcohol.