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J Bohr

Publications and source records attributed to J Bohr.

At least 19 recordsLinked to original sources
PubMed2007

Activation of extracellular regulated kinases (ERK1/2) but not AKT predicts poor prognosis in colorectal carcinoma and is associated with k-ras mutations.

Signal transduction and modulation represent central mechanisms in cellular processes such as cell-cycle regulation, oncogenesis, and apoptosis. The aim of this study was to determine the prognostic relevance of two kinases important in the regulation of cell proliferation and apoptosis in 135 colorectal cancer cases: AKT and extracellular regulated kinases (ERK1/2). We investigated the relationship of phospho-ERK1/2 (pERK1/2) and phospho-AKT (pAKT) with associated parameters (EGFR, COX-2, cyclin-D1), proliferative activity (Ki-67), and apoptosis (TUNEL) using immunohistochemistry. Additionally, the k-ras gene was screened for mutations to determine its putative association with ERK1/2 activation. Activation of ERK1/2 but not AKT correlated statistically with the presence of k-ras mutations (P = 0.015). Survival analysis of phospho-ERK1/2 immunoexpression showed a significant correlation with decreased overall survival (OS). The multivariate Cox regression analysis identified pERK1/2 as an independent prognostic parameter (P = 0.005). Activation of ERK1/2 in colorectal cancer may indicate aggressive tumor behavior and may constitute an independent prognostic factor. Furthermore, our data suggest that mutations of the k-ras oncogene may induce activation of ERK1/2. We propose immunohistochemical determination of pERK1/2 status as a promising candidate for the identification of high-risk patients who would benefit from new anticancer drugs targeting the ERK pathway.

Colorectal Neoplasms↗
PubMed2006

Systematic review: microscopic colitis.

BACKGROUND: Collagenous and lymphocytic colitis are fairly common causes of chronic non-bloody diarrhoea, especially in elderly female. AIM: To present a systematic review of microscopic colitis. METHODS: A PubMed search using the MeSH terms microscopic colitis, collagenous colitis, lymphocytic colitis and chronic diarrhoea was performed. RESULTS: Annual incidence of each disorder is 4-6/100,000 inhabitants. The aetiology is unknown. Clinical characteristics are well described and there is an association with autoimmune diseases. Budesonide is the best-documented short-term treatment of collagenous colitis. In meta-analysis pooled odds ratio for clinical response after 6-8 weeks of treatment was 12.3 (95% CI: 5.5-27.5) in comparison with placebo. The evidence for bismuth subsalicylate is weaker and the effectiveness of other alternatives such as loperamide, cholestyramine, aminosalicylates, probiotics, or Boswellia serrata extract is unknown. Although unproven, in unresponsive severe disease azathioprine or methotrexate may be tried. No controlled trials have been carried out in lymphocytic colitis. The long-term prognosis of microscopic colitis is good, serious complications are rare and there is no increased mortality. CONCLUSIONS: Clinical and epidemiological aspects of microscopic colitis are well described. Budesonide is the best-documented short-term therapy in collagenous colitis, but the optimal long-term strategy needs further study. Controlled treatment data of lymphocytic colitis are awaited for.

Aged↗
PubMed2006

Overexpression of cyclo-oxygenase-2 is an independent predictor of unfavourable outcome in node-negative breast cancer, but is not associated with protein kinase B (Akt) and mitogen-activated protein kinase (ERK1/2, p38) activation or with Her-2/neu signalling pathways.

BACKGROUND AND AIM: The production of prostaglandins is regulated by cyclo-oxygenases (COXs), which also have a role in tumour development and progression in various malignancies, including breast cancer. The mechanisms by which COX-2 contributes to unfavourable prognosis are still poorly understood. The association between expression of COX-2 and possible linked signalling pathways-namely, Akt, extracellular regulated kinases (ERK1/2), the stress-activated kinase p38 or Her-2/neu-is assessed in a series of 113 node-negative breast cancers. RESULTS: COX-2 was identified as an independent prognostic factor (p = 0.034) in node-negative breast cancer by survival analysis. The lack of a relationship between COX-2 expression and activated Akt, Erk1/2, p38 and Her-2/neu was indicated by statistical analysis. CONCLUSIONS: The prognostic effect of COX-2 expression on lymph node-negative breast cancer is confirmed-COX-2 is probably not regulated by HER-2, Akt, Erk1/2 or p38. Further studies are necessary for the elucidation of the signalling pathways responsible for the modification of COX-2 expression and the increased aggressiveness of breast cancers overexpressing COX-2.

Aged↗
PubMed2004

Microscopic colitis: a common diarrhoeal disease. An epidemiological study in Orebro, Sweden, 1993-1998.

BACKGROUND: Microscopic colitis, including collagenous colitis and lymphocytic colitis, mainly affects middle aged and older subjects, with a female predominance in collagenous colitis. The diseases have previously been regarded as rare. We present an epidemiological study of microscopic colitis in a well defined Swedish population. METHODS: Patients were retrospectively searched for in colonoscopy reports of those who had a colonoscopy in the period 1993-1998 for non-bloody diarrhoea. All colonic mucosal biopsies were reassessed using strict diagnostic criteria. RESULTS: Biopsies from 1018 patients were reassessed. Fifty one (45 female) collagenous colitis patients and 46 (31 female) lymphocytic colitis patients were diagnosed. Median age at diagnosis was 64 years in collagenous colitis and 59 years in lymphocytic colitis. The mean annual incidence of collagenous colitis was 4.9/10(5) inhabitants (95% confidence interval (CI) 3.6-6.2/10(5)) and of lymphocytic colitis 4.4/10(5) inhabitants (95% CI 3.1-5.7/10(5)). The annual incidence of collagenous colitis increased from 3.7/10(5) in 1993-1995 to 6.1/10(5) in 1996-1998 (difference 2.4/10(5) (95% CI -0.3-5.1/10(5))) whereas the incidence of lymphocytic colitis increased from 3.1/10(5) to 5.7/10(5) (difference 2.6/10(5) (95% CI 0.1-5.2/10(5))). CONCLUSIONS: The annual incidences of collagenous colitis and lymphocytic colitis are higher than considered previously and are now equal to the incidence of Crohn's disease in Sweden, and combined rates approach the incidence of ulcerative colitis. Microscopic colitis was diagnosed in 10% of all patients with non-bloody diarrhoea referred for colonoscopy and in almost 20% of those older than 70 years.

Adolescent↗
PubMed2004

Lymphocytic colitis: a retrospective clinical study of 199 Swedish patients.

BACKGROUND: Lymphocytic colitis is characterised by chronic diarrhoea and specific microscopic changes in a macroscopically normal colonic mucosa. We report clinical features and treatment outcome in a large patient cohort. METHODS: Patients were searched for in 24 Swedish gastroenterology clinics. The biopsy material was reassessed using strict histopathological criteria. Clinical data were obtained from medical notes. RESULTS: Lymphocytic colitis was diagnosed in 199 cases. The female:male ratio was 2.4:1. Median age at diagnosis was 59 (48-70) years. The most frequent symptoms were diarrhoea (96%), abdominal pain (47%), and weight loss (41%). The course was chronic intermittent in 30% of patients, chronic continuous in 7%, and a single attack in 63%, and in these cases the disease duration was 6 (4-11) months. Seventy nine (40%) patients reported associated diseases, of which thyroid disorders, coeliac disease, and diabetes mellitus were the most common. In 34 first or second degree relatives of 24 (12%) patients, a family history of ulcerative colitis, Crohn's disease, collagenous colitis, or coeliac disease was reported. Drug induced disease was suspected in 19 (10%) patients. A non-significant peak of disease onset was seen in December-January. More than 80% of treated patients improved on corticosteroids, including budesonide. CONCLUSIONS: A family history of other bowel disorders is a new finding. The sudden onset and single attack of limited duration may support a possible infectious cause in some cases. Drugs may cause lymphocytic colitis.

Aged↗
PubMed2003

Luminal nitric oxide and epithelial expression of inducible and endothelial nitric oxide synthase in collagenous and lymphocytic colitis.

BACKGROUND: Colonic nitric oxide (NO) production in collagenous colitis (CC) has been studied in a small number of patients and found increased. The cellular source of NO is believed to be the colonic epithelial cells. The aim of this study was to investigate colonic NO levels in patients with CC and lymphocytic colitis (LC), to compare with the histopathological status and with the clinical activity, and to assess the epithelial expression of inducible and endothelial nitric oxide synthase (iNOS and eNOS). METHODS: We included 19 patients with CC, 8 patients with LC and 15 controls. During colonoscopy, luminal gas was sampled and NO levels were measured using the chemiluminescence technique. Mucosal biopsies were obtained for routine histopathologic examination and immunohistochemical studies of iNOS and eNOS. Clinical activity, as measured by the mean frequency of daily bowel movements during the week prior to colonoscopy, was assessed. RESULTS: Luminal NO levels, median (25-75 percentiles), in the patients with CC and LC were greatly increased compared to the controls, 1673 (145-8143) parts per billion (ppb) and 1838 (1065-2694) ppb versus 28 (20-46) ppb (P < 0.005, both). A positive association was seen between NO levels and histopathological status as well as clinical activity. Strong expression of iNOS was seen in the surface epithelium in 5 of 6 patients with CC and in 2 of 5 patients with LC. CONCLUSIONS: The fact that luminal NO levels are related to histopathological status and correlate with clinical activity indicates that NO is involved in the pathophysiology of CC and LC. The epithelial cells are the most likely source of luminal NO.

Adolescent↗
PubMed2002

Yersinia species in collagenous colitis: a serologic study.

BACKGROUND: The etiology of collagenous colitis is unknown. An infectious cause seems a possibility, and in a recent report three out of six patients with collagenous colitis were shown to have had an infection with Yersinia enterocolitica. The aim was to investigate the occurrence of Yersinia antibodies in collagenous colitis. METHODS: Sera from 32 collagenous colitis patients and 17 healthy controls were analysed for antibodies against Yersinia virulence proteins. RESULTS: Collagenous colitis patients had Yersinia antibodies more often than the controls, 9 having a positive and 4 an intermediate antibody score of the 32 patients. In comparison, I out of 17 controls had a positive and 2 an intermediate antibody score, which represents a strong, although not significant, trend (P = 0.078). CONCLUSION: The data showed that Yersinia antibodies are more common in collagenous colitis patients than in healthy controls. In some cases, Yersinia might have been the triggering event in the development of collagenous colitis.

Adult↗
PubMed2001

Familial occurrence of microscopic colitis: a report on five families.

BACKGROUND: The etiology and pathogenesis of microscopic colitis is unknown. Whether genetic predisposition is of importance, as in many other gastrointestinal diseases, is unknown. Familial occurrence of collagenous colitis has earlier been reported only in two families. METHODS: Familial occurrence of microscopic colitis was searched for in a Swedish national microscopic colitis register. RESULTS: Familial occurrence of microscopic colitis was identified in five families. In all families a sister-sister relationship was found. Two sisters with collagenous colitis had been living apart in different Nordic countries for many years before developing the disease. In one pair, the smoking sister had collagenous colitis and the never smoking sister had lymphocytic colitis. CONCLUSIONS: Considering the relative rarity of microscopic colitis, these findings indicate that a genetic predisposition may be of importance.

Adult↗
PubMed2000

Prediction of protein secondary structure at 80% accuracy.

Secondary structure prediction involving up to 800 neural network predictions has been developed, by use of novel methods such as output expansion and a unique balloting procedure. An overall performance of 77.2%-80.2% (77.9%-80.6% mean per-chain) for three-state (helix, strand, coil) prediction was obtained when evaluated on a commonly used set of 126 protein chains. The method uses profiles made by position-specific scoring matrices as input, while at the output level it predicts on three consecutive residues simultaneously. The predictions arise from tenfold, cross validated training and testing of 1032 protein sequences, using a scheme with primary structure neural networks followed by structure filtering neural networks. With respect to blind prediction, this work is preliminary and awaits evaluation by CASP4.

Neural Networks, Computer↗
PubMed2000

Microwave-enhanced folding and denaturation of globular proteins.

It is shown that microwave irradiation can affect the kinetics of the folding process of some globular proteins, especially beta-lactoglobulin. At low temperature the folding from the cold denatured phase of the protein is enhanced, while at a higher temperature the denaturation of the protein from its folded state is enhanced. In the latter case, a negative temperature gradient is needed for the denaturation process, suggesting that the effects of the microwaves are nonthermal. This supports the notion that coherent topological excitations can exist in proteins. The application of microwaves hold promises for a wide range of biotechnological applications, such as protein synthesis, protein aggregation, etc., and may have implications for biological systems as well.

Biophysical Phenomena↗
PubMed2000

Collagenous and lymphocytic colitis: a clinical and histopathological review.

Collagenous colitis and lymphocytic colitis are newly described colitides that are only diagnosable microscopically; therefore, both are known under the umbrella term 'microscopic colitis'. This is a short review of the clinical findings, and epidemiological and basic observations of these relatively little described colitides belonging to the group of inflammatory bowel diseases.

Biopsy↗
PubMed2000

Microwave enhanced kinetics observed in ORD studies of a protein.

Microwaves are shown to affect the kinetics of conformational changes of the protein beta-lactoglobulin. Microwaves can accelerate conformational changes in the direction towards the equilibrium state. This applies both for the folding and the unfolding processes. Cold denaturing thermal unfolding of the proteins is accelerated by negative temperature gradients. Microwave irradiation of the protein solution heated it by about 0.3 degree, and hence the observed acceleration of denaturing is therefore non-thermal.

Kinetics↗
PubMed1997

Protein folding and wring resonances.

The polypeptide chain of a protein is shown to obey topological constraints which enable long range excitations in the form of wring modes of the protein backbone. Wring modes of proteins of specific lengths can therefore resonate with molecular modes present in the cell. It is suggested that protein folding takes place when the amplitude of a wring excitation becomes so large that it is energetically favorable to bend the protein backbone. The condition under which such structural transformations can occur is found, and it is shown that both cold and hot denaturation (the unfolding of proteins) are natural consequences of the suggested wring mode model. Native (folded) proteins are found to possess an intrinsic standing wring mode.

Journal Article↗
PubMed1997

Molecular wring resonances in chain molecules.

It is shown that the eigenfrequency of collective twist excitations in chain molecules can be in the megahertz and gigahertz range. Accordingly, resonance states can be obtained at specific frequencies, and phenomena that involve structural properties can take place. Chain molecules can alter their conformation and their ability to function, and a breaking of the chain can result. It is suggested that this phenomenon forms the basis for effects caused by the interaction of microwaves and biomolecules, e.g., microwave assisted hydrolysis of chain molecules.

Biopolymers↗
PubMed1997

Coherent topological phenomena in protein folding.

A theory is presented for coherent topological phenomena in protein dynamics with implications for protein folding and stability. We discuss the relationship to the writhing number used in knot diagrams of DNA. The winding state defines a long-range order along the backbone of a protein with long-range excitations, 'wring' modes, that play an important role in protein denaturation and stability. Energy can be pumped into these excitations, either thermally or by an external force.

Mathematics↗
PubMed1997

Increased nitric oxide production in collagenous and lymphocytic colitis.

The production of nitric oxide (NO) is increased in active ulcerative colitis and in Crohn's disease. We have studied NO production in collagenous colitis (CC) and lymphocytic colitis (LC), both of which are inflammatory bowel disorders of unknown aetiology. NO levels were measured directly in gas sampled from the colon during colonoscopy. Plasma levels of NO metabolites (nitrate/nitrite) were also measured. Luminal NO levels were more than 100 times higher in patients with CC compared with controls. In addition, plasma levels of nitrate/nitrite were increased in the patients as compared with controls. Measurements of NO directly in the colon or its oxidation products in plasma may be a helpful tool in further understanding the role of NO in the pathophysiology of CC and LC. Moreover, it is tempting to speculate that these measurements could be clinically useful in the diagnosis and therapy monitoring of these two inflammatory bowel diseases.

Adult↗
PubMed1997

Protein distance constraints predicted by neural networks and probability density functions.

We predict interatomic Calpha distances by two independent data driven methods. The first method uses statistically derived probability distributions of the pairwise distance between two amino acids, whilst the latter method consists of a neural network prediction approach equipped with windows taking the context of the two residues into account. These two methods are used to predict whether distances in independent test sets were above or below given thresholds. We investigate which distance thresholds produce the most information-rich constraints and, in turn, the optimal performance of the two methods. The predictions are based on a data set derived using a new threshold which defines when sequence similarity implies structural similarity. We show that distances in proteins are predicted more accurately by neural networks than by probability density functions. We show that the accuracy of the predictions can be further increased by using sequence profiles. A threading method based on the predicted distances is presented. A homepage with software, predictions and data related to this paper is available at http://www.cbs.dtu.dk/services/CPHmodels/.

Amino Acids↗