Pro-inflammatory response and adverse drug reactions: Mechanisms of action of ximelagatran on chemokine and cytokine activation in a monocyte in vitro model

There is a lack of suitable human in vitro systems which can predict drug hepatotoxicity that in many cases involves inflammatory responses mediated by macrophages. In the present investigation we used an in vitro model based on human THP-1 cells to evaluate the inflammatory cytokine/chemokine activation properties of ximelagatran, a drug previously shown to cause elevation of liver transferases in a subset of patients. Treatment of the cells with ximelagatran caused an intracellular accumulation of the metabolites hydroxymelagatran and melagatran. A decreased viability and increased release of the pro-inflammatory cytokines and chemokines IL-8, VEGF and MCP-1 was seen. Ximelagatran exposure caused activation of ERK1/2 and JNK as evident from determination of the phosphorylation status. In accordance, the release of IL-8 was attenuated by inhibitors of the ERK- and JNK-pathways. It is concluded that human monocytes might constitute a valuable additional in vitro model for monitoring the basis for cytotoxic action of drugs.     

Who is maintaining weight in a middle-aged population in Sweden? A longitudinal analysis over 10 years

Background  

Obesity has primarily been addressed with interventions to promote weight loss and these have been largely unsuccessful. Primary prevention of obesity through support of weight maintenance may be a preferable strategy although to date this has not been the main focus of public health interventions. The aim of this study is to characterize who is not gaining weight during a 10 year period in Sweden.     

Flat Serrated Adenomas and Flat Tubular Adenomas of the Colorectal Mucosa: Differences in the Pattern of Cell Proliferation

In the present work we have investigated the cell proliferation pattern of flat serrated adenomas and flat tubular adenomas. For this purpose tissue sections from 23 consecutive flat serrated adenomas and 22 consecutive flat tubular adenomas of the colorcctal mucosa were challenged with MID1, a monoclonal antibody directed against a proliferation-related antigen. The results (including semi-quantitative studies) demonstrated that, whereas flat serrated adenomas had a high cell proliferation at the lower part of the crypts, flat tubular adenomas had a high cell proliferation in the upper part of the crypts. In serrated adenomas with invasive adenocarcinoma, high cell proliferation was demonstrated both at the lower portion of the crypts and in the subjacent submucosa. This suggests that the cells of the lower portion of the crypts in serrated adenomas are truely neoplastic, with the capacity to evolve into invasive growth. The difference in cell proliferation betweeen the two types of flat lesions reported here is a new argument in favor of the classification of flat serrated adenomas as a novel and independent type of neoplastic change of the colorectal mucosa.     

Estrogens affect endothelin-1 mRNA expression in LNCaP human prostate carcinoma cells

OBJECTIVE: To study effects of estrogens on endothelin-1 (ET-1) mRNA expression in the androgen-sensitive LNCaP-FGC cell line and its androgen-resistant derivative LNCaP-r. Further, if effects of estrone sulfate (E1S) are mediated via conversion to estradiol-17beta (E2). Estrogens have been shown to down-regulate ET-1, a mediator of the osteoblastic response of bone to metastatic prostate cancer.METHODS: Cells were grown in steroid-depleted medium and incubated for 2-4 and 48 hours with 0, 1, 10, and 100 nM of either E1S or E2. mRNA levels were measured with an RT-PCR technique. Estrogen metabolism by LNCaP-FGC cells was studied by incubation with estrone (E1) and E1S at the same conditions, followed by determination of E1 and E2.RESULTS: ET-1 mRNA expression in LNCaP-FGC cells was significantly suppressed by E2 and E1S following incubation for 2-4h but after 48 h only by E2 at 1 and 10nM and in LNCaP-r cells only by E2 at 100 nM following 2-4h of incubation. ET-1 mRNA expression was significantly higher in untreated LNCaP-r than in untreated LNCaP-FGC cells. E1 was efficiently transformed into E2 by LNCaP-FGC cells but very little to E1 and no E2 was formed from E1S.CONCLUSION: ET-1 mRNA expression in LNCaP-FGC can be inhibited by E2, but also by its prehormone E1S. The lack of formation of E2 from E1S suggests a mode of action not related to classical steroid receptors. The higher level of ET-1 mRNA expression found in LNCaP-r cells may reflect the capability of a hormone refractory tumor to maintain activity on its own, independently of known regulatory mechanisms such as sex steroids.     

Survival of transplanted human corneal stem cells. Case report

PURPOSE: To report a case history involving long-term survival of transplanted human corneal stem cells. METHODS: A male patient with severe bilateral chemical burns received six corneal transplants, all of which failed. He subsequently received combined corneal transplants and stem cell transplants, which have remained clear for 3 and 4 years respectively. One of the donors was female. We studied the gender of the epithelial cells of the cheek of the patient and of the two grafts using fixation and fluorescent in situ hybridization (FISH) analyses. RESULTS: In the graft from the female donor, 30% of the epithelial cells were of female origin. All the epithelial cells from the cheek and the other graft were of male origin. CONCLUSION: This case demonstrates that transplanted human corneal stem cells can survive and replicate in the long-term (3 years) without systemic immunosuppression. The case also indicates that a minority (30%) of healthy transplanted epithelial cells is enough to present a clear graft with a clinically healthy ocular surface.     

Applicability of a modified Edman procedure for measurement of protein adducts: mechanisms of formation and degradation of phenylthiohydantoins

Adducts to N-terminal valine residues in hemoglobin (Hb) are used for monitoring in vivo doses of electrophiles and are quantitated by means of a modified Edman procedure, the "N-alkyl Edman procedure". In the reaction with pentafluorophenyl isothiocyanate, N-alkylated valines cyclize and detach from the protein as pentafluorophenylthiohydantoins (PFPTHs) much more efficiently than do unsubstituted N-terminal valine residues. The mechanisms of this reaction, and of possible degradation reactions, have been studied with model compounds using phenyl- and pentafluorophenyl isothiocyanate. The rapid cyclization to N-alkylvaline-PTHs occurs as a consequence of the influence of substituents on ring formation. This facilitated cyclization favors a direct attack by the thiocarbamoyl nitrogen atom on valine-C-1, and is also observed to occur slowly at unsubstituted N-terminal valines. Such cyclization is favored in protic solvents. Under alkaline conditions and in the presence of air, hydrolytic and oxidative processes give rise to degradation products. The PTH derivatives of N-alkylvaline are less apt to undergo such reactions than are the corresponding derivatives of unsubstituted valine. We conclude that the presence of an N-substituent exerts a greater influence on the cyclization process than the structure of the amino acid or of the Edman reagent. For adducts of different structures, the method has broad applicability, for which the limits, however, are not yet explored. The knowledge from the studies is valid not only for the N-alkyl Edman procedure, but also, to some extent, for the classical Edman degradation reaction. The oxidative side reaction gave rise to the invention of a novel synthesis route for insertion of nucleophiles at carbon-5 in thiohydantoins. The present investigation provides a basis for the N-alkyl Edman procedure, facilitating new toxicological applications.     

Increasing fecal butyrate in ulcerative colitis patients by diet: controlled pilot study

Topical butyrate has been shown to be effective in the treatment of ulcerative colitis (UC). Butyrate is derived from colonic fermentation of dietary fiber, and our aim was to study whether UC patients could safely increase the fecal butyrate level by dietary means. We enrolled 22 patients with quiescent UC (mean age, 44 years; 45% women; median time from last relapse, 1 year) in a controlled pilot trial lasting 3 months. The patients were instructed to add 60 g oat bran (corresponding to 20 g dietary fiber) to the daily diet, mainly as bread slices. Fecal short-chain fatty acids (SCFAs) including butyrate, disease activity, and gastrointestinal symptoms were recorded every 4 weeks. During the oat bran intervention the fecal butyrate concentration increased by 36% at 4 weeks (from 11 +/- 2 (mean +/- SEM) to 15 +/- 2 micromol/g feces) (p < 0.01). The mean butyrate concentration over the entire test period was 14 +/- 1 micromol/g feces (p < 0.05). Remaining fecal SCFA levels were unchanged. No patient showed signs of colitis relapse. Unlike controls, the patients showed no increase in gastrointestinal complaints during the trial. Yet patients reporting abdominal pain and reflux complaints at entry showed significant improvement at 12 weeks that returned to baseline 3 months later. This pilot study shows that patients with quiescent UC can safely take a diet rich in oat bran specifically to increase the fecal butyrate level. This may have clinical implications and warrants studies of the long-term benefits of using oat bran in the maintenance therapy in UC.