Investigations on etiology of Crohn's disease

Many investigators have tried to prove a relationship between Crohn's disease andMycobacteria. Recent evidence suggests that some autoimmune diseases may be initiated through molecular mimicry between mycobacterial stress protein antigens and their human homologs. We investigated whether antibody to stress proteins was more frequent in patients with Crohn's disease than controls. We used ATP binding to separate stress proteins (heat-shock-induced,de novo-synthesized, and constitutively expressed ATP-binding proteins) from crude extracts obtained fromMycobacteria and from an SV40-transformed human epithelial cell line that expresses a heat-shock protein, hsp73, as a complex with SV40 T antigen. We used immunoblots to compare sera from 34 patients with Crohn's disease, 14 with ulcerative colitis, and 14 with duodenal or gastric ulcers (noninflammatory bowel disease control patients). We found no statistically significant pattern or frequency of antibodies against single proteins or a combination of mycobacterial or human stress proteins. These observations do not support the hypothesis that a humoral immune response to stress proteins ofMycobacteria is important in the pathogenesis of Crohn's disease.     

Differential expression of poly(A)-adjacent sequences of mammary tumor virus RNA in murine mammary cells

Two DNA probes representative of either the entire mouse mammary tumor virus (MMTV) genome or the poly(A)-adjacent sequences at the 3' end of MMTV RNA were synthesized with calf thymus DNA or oligo(dT) primers, respectively. These probes were used to study the expression of endogenous MMTV sequences in several BALB/c mammary tumor cell lines, in normal lactating BALB/c tissue, and in a cloned C3H tumor cell line. Both probes were characterized with respect to their rates of hybridization with template RNA, their size as determined by alkaline sucrose gradient centrifugation, and the thermal stability of the cDNA.MMTV RNA hybrids. In addition, the ability of the calf thymus oligodeoxy-nucleotide- or oligo(dT)-primed probes to protect (125)I-labeled MMTV RNA or (125)I-labeled poly(A)-adjacent MMTV RNA sequences from S1 nuclease digestion was determined. Hybridization analysis with these two probes indicated that (i) there were approximately 20-fold more oligo(dT)-primed sequences in BALB/c lactating tissue than there were sequences representing the entire genome; (ii) in BALB/c tumor cells, the oligo(dT):random oligonucleotide-primed cDNA sequence ratio was reduced to 4:1; and (iii) in virus-producer C3H tumor cells, there was only a 2-fold excess of oligo(dT)-primed sequences over that observed with a representative cDNA. These results are consistent with the presence of subgenomic viral mRNA species, integration of partial proviral copies, or altered mRNA processing.     

In vivo bioluminescent imaging of a new model of infectious complications in head-injury rats

Infectious complications are responsible for 10-25% of mortality in head-injured patients. In the present work we developed a model of infectious complications in head-injury rats using Escherichia coli (E. coli) with a stable copy of the lux operon, and monitored the infection in vivo by optical imaging. Rats were randomized into three groups: AL (healthy rats), HI (head-injury rats), and HI-EC (HI rats+single enteral bolus of E. coli, 1.3×10(9)/rat given 2 days after HI). Infection was evaluated with a camera at 2 and 6?h after E. coli challenge. Blood and organs were sampled to assess biological parameters. HI was associated with body weight loss, muscle atrophy, and plasma amino acid disturbances, in particular glutamine depletion (AL 919±37 versus HI 647±25 and HI-EC 717±20?μmol/L; p<0.05). In the HI-EC rats, the luminescence signal was observed at T+2 (mean [range]: 34,778?cpm [1617-2,918,810]), and was significantly decreased at T+6 (0?cpm [0-847,922]; p<0.05). Bacterial challenge was associated with a specific body weight loss and a decrease in gastrocnemius protein content, in alanine (AL 512±41 versus HI-EC 395±29?μmol/L; p<0.05), and in sulfur plasma amino acids. In conclusion, we propose a controlled model of HI with infectious complications characterized by specific metabolic alterations. Combined with the in vivo monitoring of the infection by bioluminescence, this model offers a valuable tool to evaluate specific strategies for HI patients.     

The role of high levels of dietary fat in 7,12-dimethyl-benzanthracene-induced mouse mammary tumorigenesis: lack of an effect on lipid peroxidation

The effects of dietary fat on 7,12-dimethylbenzanthracene (DMBA)-inducedmammary tumorigenesis were examined in BALB/c female mice. Inthe first experiment, BALB/c mice were treated with a totaldose of 1,3, or 6 mg DMBA to induce mammary tumors. One weekafter the last dose of DMBA, the mice were placed on a 5% (LF)or 20% (HF) corn oil semi-purified diet. The 20% corn oil dietresulted in a significantly decreased mean tumor latency periodin each of the three groups of mice (p <0.05). However, themammary tumor incidences at 11 months after DMBA treatment werethe following: 6 mg DMBA (LF-14/32, HF-17/32); 3 mg DMBA (LF-13/50,HF-14/50); 1 mg (LF-2/50, HF-6/50). In the second experiment,prolonged hormonal stimulation by pituitary isografts, but nota HF diet, enhanced the incidence of mammary tumors in BALB/cmice given a threshold dose of DMBA (0.5 mg). In a further attemptto examine the mechanism of the enhancing effects of dietaryfat, lipid peroxidation was measured in the microsomal-mitochondrialfractions of the mammary glands by two assays; measurementsof conjugated dienes and TBA reactants (malonyldialdehyde).The high fat diet had no effect on the levels of conjugateddienes in mammary cell membrane preparations and decreased thelevels of TBA reactants (malonyldialdehyde). The results indicatedthat a high fat diet did not lead to enhanced levels of lipidperoxidation in preparations of microsomal mitochondrial membranesfrom mouse mammary glands. The implications of these resultsare discussed with respect to the role of dietary fat as a promoterof mouse mammary tumorigenesis.     

Desmoid fibroma of soft tissues of extra-abdominal sites: review of the literature apropos of a case located at the posterior face of the thigh

The authors report a case of desmoid fibroma on the posterior surface of the thigh in a woman during the post-partum period. This is a rare site for this tumour. CT scan combined with MRI appears to be useful for diagnosis. Treatment is strictly surgical, but depends on the histological benign nature and the local malignancy. Surgery is generally conservative with risks of recurrence and occasionally amputation is necessary.     

Correlation of amino acid fucoside labeling patterns with tumorigenicity of mouse mammary epithelial cells

The amino acid fucosides of tumorigenic and nontumorigenic mouse mammary gland-derived cells were studied. The cells examined included tumorigenic cell lines derived from mammary carcinomas of the following etiologies: induction by hormone; virus; and chemical carcinogen. Also studied were cells derived from normal mammary glands and several clones of cells, which were derived from a mammary carcinoma but were not demonstrably tumorigenic at lower passage levels after cloning, while they were highly tumorigenic at higher passage levels. Cells were cultured in medium supplemented with radiolabeled fucose and extracted, and extracts were analyzed for the amino acid fucosides. Radiolabeled compounds which comigrated with the amino acid fucosides glucosylfucosylthreonine, fucosylthreonine, and fucosylserine were observed. There was a distinctive difference between the tumorigenic and nontumorigenic cells; the ratio of fucosylthreonine plus fucosylserine to glucosylfucosylthreonine was higher in all tumorigenic cells as compared to the ratio observed for the nontumorigenic cells.     

Frequent detection of polyomaviruses in stool samples from hospitalized children

BACKGROUND. Infection with BK virus (BKV) generally occurs early during life, but its mode of transmission has not been clearly defined. We tested the hypothesis that polyomavirus shedding in stool may be a source of BKV exposure.METHODS. Pediatric stool and rectal swab samples were tested for the presence of polyomavirus DNA by a polymerase chain reaction (PCR) assay that could detect a conserved region in the large T antigen gene of BKV, JC virus (JCV), and simian virus 40 (SV40). The specific viruses detected by this assay were confirmed by DNA sequence analysis of the PCR amplicons.Results. Of 120 samples collected from 99 patients, 54 (45.0%) were positive for polyomavirus DNA. Of the 99 patients, 46 (46.5%) had at least 1 positive sample, with 38 (38.4%) positive for BKV and 8 (8.1%) positive for SV40. JCV was not detected. There was no association between polyomavirus fecal shedding and age, sex, race/ethnicity, immune status, or symptoms of gastrointestinal disease in the children studied. The BKV strains detected displayed polymorphisms in the T antigen sequence.Conclusions. Polyomaviruses are frequently present in stool samples from hospitalized children. These findings suggest that fecal-oral transmission of BKV may play a role in the ubiquity of infection.