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Ulcerative colitis (UC) is a chronic inflammatory disease of the colon with a high incidence of colon cancer. Dysplasia is a precursor to carcinoma and a predictor of malignant potential; epithelia containing high-grade or severe dysplasia is most likely to develop cancer. The cellular oncogene c-src and its viral homologue v-src (the transforming gene of Rous sarcoma virus) encode 60-kD cytoplasmic, membrane-associated protein tyrosine kinases. For the viral protein or transforming mutants of the cellular protein (Src), a close correlation exists between elevated tyrosine kinase activity and malignant transformation of cells. Previously, we and others observed elevated Src activity in sporadic colon carcinomas and benign adenomas at greatest risk for developing cancer (those with large size, villous architecture, and/or severe dysplasia). Here we report that Src activity and protein abundance are also elevated in neoplastic UC epithelia. Activity is highest in malignant and severely dysplastic epithelia, and 6-10-fold higher in mildly dysplastic than in nondysplastic epithelia. Thus, Src activity is elevated in premalignant UC epithelia, which is at greatest risk for developing cancer. The data suggest that activation of the src proto-oncogene is an early event in the genesis of UC colon cancer.

Hereditary tyrosinemia type I (HTT-I) is an inherited metabolic disorder with severe liver disease and a high risk for hepatic malignancy. Patients with HTT-I are monitored with repeated analyses of serum amino acids, urine succinylacetone, and serum alpha-fetoprotein (AFP). Oncofetal markers CA 125 and CA 19-9 are elevated in serum of patients with various gastrointestinal diseases and malignancy. To study the biology of oncofetal antigens in tyrosinemia and to assess the possible usefulness of these markers in HTT-I, we studied serum concentrations of CA 125 (n = 160) and CA 19-9 (n = 188), together with AFP (n = 337), in serial samples from 10 patients. At early stages of the disease, most children with an acute type of disease had a remarkably elevated serum CA 125 concentration (153-1560 IU/L) that normalized gradually after the institution of therapy. Serum CA 125 levels may thus reflect acute metabolic imbalance in fulminant HTT-I. The patients with a chronic type of disease showed CA 125 levels within the normal range at diagnosis that slowly increased as the liver condition worsened. These concentrations, however, never reached values seen in acute HTT-I. Serum concentration CA 19-9 in HTT-I was mostly normal. Serum AFP levels fluctuated in all patients and positively correlated with tests for metabolic state and biliary function. A distinct increase in the serum AFP level was recorded in association with the detection of massive hepatocellular carcinoma and also preceded metabolic imbalance leading to porphyria crises.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of nutritional copper (Cu) deficiency on the antiinflammatory activity and pharmacokinetics of aspirin (ASA) was investigated in rats. Male, weanling Sprague-Dawley rats were fed either a Cu-deficient (CuD) or Cu-sufficient (CuS) diet for 49-50 d. The antiinflammatory activity of ASA was studied using the carrageenan-induced paw edema (CPE) test. ANOVA analyses of edema volumes at 2, 3, 4, 5, and 21 h postcarrageenan indicated significant differences between groups. The percent inhibition of edema due to ASA treatment in CuS was lower than that in CuD rats at 5 h, AUC5h, and AUC21h. ASA was found to be significantly more effective in inhibiting the CPE in CuD rats when compared to the CuS rats. Thus, we hypothesized that the increase in ASA's antiinflammatory activity in CuD rats was a result of a decrement in its elimination during nutritional Cu deficiency. The elimination of ASA in CuD and CuS rats was studied using an iv dose of 200 mg/kg. Concentrations of ASA and salicylic acid (SA) were determined in blood; whereas the concentrations of SA, salicylic phenol-glucuronide (SPG), and salicyluric acid (SUA) were determined in urine by HPLC. The results of the pharmacokinetic analyses from blood and urinary data indicated no significant differences in the disposition of ASA between CuD and CuS rats. For instance, the total body clearance for ASA (mean +/- SD, mL/min/kg) was 37.9 +/- 9.4 and 38.5 +/- 13.9 (p > 0.05); and the volume of distribution (Vd) for ASA (mean +/- SD, mL/kg) was 385.5 +/- 110.3 and 397.1.1 +/- 137.9 (p > 0.05) for CuD and CuS groups, respectively. Thus, contrary to our hypothesis, the enhanced antiinflammatory activity of ASA in CuD rats does not appear to be mediated via a decrement in the elimination of the drug. In addition, plasma ASA-esterase activity was found to be independent of Cu nutritional status.

The different parameters affecting the accuracy and reliability of the dextran-coated charcoal adsorption assay for characterization of retinoic acid receptors ligand binding activity were investigated. Using dextran-coated charcoal (DCC) at a final 10 mg/ml concentration, an efficient adsorption of free [3H]retinoic acid was observed with a yield in the range 99.2 to 99.8% for ligand concentrations varying from 10(-9) to 10(-4) M. Nonspecific adsorption of retinoic acid reached 50% to polystyrene and silanized glass and 70% to uncoated glass. Results obtained by the DCC method and by gel-filtration assay were correlated; however, the DCC assay appeared easier to perform and gave more reproducible results. When a careful measurement of free retinoid concentration was performed, the apparent equilibrium dissociation constant (KD) of retinoic acid was 3.1 +/- 0.4 nM and the KD of CD367, a synthetic retinoid, was 1.8 +/- 0.3 nM. Optimal pH for the binding of [3H]retinoic acid or [3H]CD367 was in the range 7.5 to 8.5. Under the conditions described for the adsorption assay, bound retinoid measurement was linearly related to the protein concentration between 0.05 and 0.25 mg/ml. At a lower protein concentration, addition of bovine serum albumin exerted a stabilizing effect on retinoid binding, allowing an accurate measurement of the number of specific binding sites. Using retinoic acid as ligand, bacterial extracts often resulted in a level of nonspecific binding in the range 10-25%. It could be lowered (4-10%) when resorting to [3H]CD367.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of reactive oxygen species (ROS) generated by a xanthine oxidase hypoxanthine system (mainly H2O2) on proteoglycan (PG) metabolism and structure was investigated in vitro, using cell monolayers of cultured rabbit articular chondrocytes and purified resident and newly synthesized proteoglycans. It was shown that ROS generated in this system frequently stimulate (at low concentrations), and consistently inhibit (at higher concentrations), the incorporation of 35SO4 and 3H-glucosamine into PG molecules synthesized by cultured chondrocytes. The inhibition of isotopes' incorporation at higher enzyme concentrations was suppressed completely by heating xanthine oxidase and allopurinol with superoxide dismutase (SOD) and catalase. ROS at high concentration also inhibited 3H-uridine incorporation but had no effect on 35SO4 and 3H-uridine uptake by the cells. They also alter hyaluronan (HA) and PG monomers by fragmenting the core protein moiety and destroying the hyaluronic acid binding region. Altered PG monomers do not interact with HA to form complexes, but fragmented HA still retain a significant PG monomer-binding capacity. PG-HA complexes are easily and irreversibly destroyed by ROS. These results suggest that ROS may at low fluxes stimulate PG-synthesis under physiological conditions and alter cartilage metabolism and structure in conditions where they are overproduced, such as in rheumatoid arthritis, and in hemochromatosis and other iron storage diseases.

The present paper describes the results of a comparative histological and quantitative analysis of iron distribution in tissues of beta 2m-/- and beta 2m+/- mice of different ages. Progressive hepatic iron overload, indistinguishable from that observed in human hemochromatosis, was found only in mice homozygous for the mutated beta 2m gene. Total iron measurements done by flame atomic absorption showed statistically significant differences between liver samples from 5 beta 2m+/- heterozygotes (468 +/- 174 micrograms/g of dry weight) and 9 mice homozygous for the mutated beta 2m gene with average total hepatic iron levels of 1583 +/- 423 micrograms/g of dry weight.

A biochemical analysis of glycosaminoglycans and collagen was performed in arteries of a 15-year old teenager who died of beta thalassemia major. The patient presented the severe clinical complications resulting from hemochromatosis, which was evidenced at autopsy and by histological examination. The arteries under study comprised the thoracic and abdominal aortas and the iliac and pulmonary arteries, which were compared with the same arteries from normal individuals. Data on total glycosaminoglycan and total collagen, including the determination of the relative contents of the different glycosaminoglycans, suggest an as yet undescribed fibrotic process in the thalassemic arteries. Also altered were the proportions of the disaccharides making up chondroitin sulfate and heparan sulfate. A reduction in the molecular weight of arterial heparan sulfate, presumably with free radical involvement, was also detected. These changes in the extracellular matrix may be ascribed to the presence of large amounts of iron in the tissue, and as such they should be expected in other disorders with chronic iron overload.

Genetic alterations of several oncogenes and tumor suppressor genes are associated with human colorectal carcinogenesis. Especially in mutations, the K-ras, p53, APC and DCC gene frequently occurred, and these gene alterations seem to have important roles in colorectal carcinogenesis. We investigated 28 human colon cancer specimens obtained from surgery and five human colon cancer cell lines by PCR-SSCP assay, PCR-OSH assay, RT-PCR or sequencing method. Forty percent of cancers from surgical specimens had Ki-ras 2 (codon 12/13), p53 (Exon 5-8), APC (MCR) gene mutations, and fifty-seven percent of them had lower expression of DCC gene that of normal matched colon mucosa of the same patient. G to A transition was the most frequent in K-ras mutational spectrum in this case; 25% of patients had both k-ras and p53 gene point mutations. Form the results, we concluded that it in colorectal carcinogenesis for both K-ras and p53 gene point mutations might not necessary occur.

Mucin-producing tumors of the pancreas (MPT) are characterized by the production of much mucin and a benign course after surgical treatment. We examined 16 cases of MPT and 20 cases of "common" pancreatic duct cell carcinomas (DCC) in regard to K-ras and p53 mutations. The mutations were detected by constant denaturant gel electrophoresis in combination with other techniques using PCR products amplified from the samples microdissected from the tissue sections. K-ras codon 12 mutations were identified in all MPT and in 95% of DCC. On the other hand, p53 mutations were found in four of 20 (20%) DCC, and p53 was immunocytochemically overexpressed in 3 of the 4 mutated cases. However, no p53 mutations and no p53 overexpression were identified in the 16 MPT. These results indicate that, although the K-ras codon 12 mutations may be almost essential for the development of both MPT and DCC, p53 mutations seemed to be involved mainly to the latters.

Iron studies were compared in 434 patients from 80 hemochromatosis families classified as putative homozygotes, heterozygotes, and normal by HLA typing. There were 28 of 255 (11%) heterozygotes with an elevated serum ferritin and 22 of 255 (8.6%) with an elevated transferrin saturation. Serum ferritin (140 +/- 10.2 micrograms/liter; mean +/- standard error) was greater in heterozygotes than in normal subjects (87 +/- 8.5 micrograms/liter; P < .05, Mann Whitney test). Transferrin saturation was greater in heterozygotes (38% +/- 0.88%) than in normal patients (29% +/- 1.1%; P < .0001). Mean hepatic iron concentration was 54 +/- 6 mumol/g (n = 17), and the hepatic iron index was < 2 in these patients. Most heterozygotes for hemochromatosis have a normal serum ferritin and transferrin saturation. Heterozygotes with minor elevations in serum ferritin or transferrin saturation do not have significant iron overload as assessed by hepatic iron concentration.

We immortalized oral keratinocytes by transfecting them with recombinant human papillomavirus (HPV) type 18 DNA and established three cell lines. These lines were morphologically different from their normal counterpart, contained integrated entire HPV-18 DNA, and expressed the viral E6/E7 genes. The cells contained less p53 protein and more c-myc mRNA than normal cells. However, they proliferated only in keratinocyte growth medium (KGM) containing low calcium and were not tumorigenic in nude mice. To test the hypothesis that tumors result from the combined effect of a "high-risk" HPV and chemical carcinogens in the human oral cavity, we exposed the immortalized cells to the chemical carcinogen N-methyl-N'-nitro-N-nitrosoguanidine. Three chemically transformed cell colonies were isolated. These cells (a) proliferated well in both KGM and Dulbecco's modified minimum essential medium containing physiological levels of calcium; (b) were capable of proliferating in nude mice; (c) contained intact, integrated HPV-18 sequences; (d) transcribed substantially more HPV-18 E6/E7, transforming growth factor-alpha, and c-myc than the immortalized counterpart; and (e) contained, like the immortalized counterpart, less wild-type p53 protein and DCC message. These data indicate that human oral keratinocytes can be transformed by sequential exposure of normal keratinocytes to a "high-risk" HPV and chemical carcinogens.

DCC is a candidate tumor-suppressor gene encoding a protein with sequence similarity to cell adhesion molecules such as N-CAM. A set of overlapping YAC clones that contains the entire DCC coding region was isolated. Studies of this YAC contig showed that the DCC gene spans approximately 1.4 Mb. For elucidation of exon-intron structure, lambda phage clones containing all known coding sequences were isolated from a genomic library. These clones were used to demonstrate the existence of 29 DCC exons, and the sequences of the exon-intron boundaries were determined for each. Twenty-three polymorphic markers from chromosome 18 were then studied in a panel of primary colorectal tumors that had lost some, but not all, of chromosome 18. In most of these tumors, the region that was lost included DCC. Finally, Southern blot and PCR-based approaches were used to search for subtle mutations in several DCC exons. One tumor that had a point mutation in exon 28 was found, resulting in a proline to histidine substitution. A second tumor with a point mutation in intron 13 was also found. The regional map and genomic structure of DCC should provide the means to more extensively study DCC gene alterations and protein function in normal and neoplastic cells.

The partially protected fragment BOC-Cys(Acm)-Ser(But)-Asn-Leu-Ser(But)-Thr(But)- Cys(Acm)-Val-Leu-Gly-Lys(epsilon-BOC)-Leu-Ser(But)-Glu(OBut)-Leu-O H of salmon calcitonin was synthesized by segment condensation in solution. Segments were synthesized in solution by the DCC/HOBt method using the phenylhydrazide as a semipermanent protecting group for protection of the carboxyl function of the C-terminal residue. The phenylhydrazide protecting group was removed by oxidation with air oxygen catalyzed by copper-pyridine complexes. The segments were then condensed by the DCC/HOBt method according to the scheme (6 + 3) + (3 + 4). The proposed synthetic scheme permits production of gram amounts of the partially protected fragment 1-16 of salmon calcitonin.

Nineteen cases of B Thalassemia have benefited from partial splenectomy at the General Surgery Service of Farhat Hached Hospital in Sousse (Tunisia). The partial splenectomy indication was to reduce hypersplenism, thus transfusion needs, to suppress splenic pain and to conserve a splenic remnant, which preserves patients' immunity. The operation was in reality a subtotal splenectomy keeping the lower pole in all cases. We had no per-operatory complication. The preoperatory bleeding was not more serious than in total splenectomy. In all the patients, we noticed reduction of about half the transfusion need, except one who had also a chronic deficit in glyco-six phospho-dehydrogenase. The average hemoglobin rate increased from 60 g/L in the pre-operatory to 80 g/L after the operation. Consequently, this reduction of transfusion needs results in the decrease of the hemochromatosis, which is one of the main complications of hypertransfused thalassemia.

Eukaryotic genomes frequently contain large numbers of repetitive RNA polymerase III (pol III) promoter elements interspersed between and within RNA pol II transcription units, and in several instances a regulatory relationship between the two types of promoter has been postulated. In the budding yeast Saccharomyces cerevisiae, tRNA genes are the only known interspersed pol III promoter-containing repetitive elements, and we find that they strongly inhibit transcription from adjacent pol II promoters in vivo. This inhibition requires active transcription of the upstream tRNA gene but is independent of its orientation and appears not to involve simple steric blockage of the pol II upstream activator sites. Evidence is presented that different pol II promoters can be repressed by different tRNA genes placed upstream at varied distances in both orientations. To test whether this phenomenon functions in naturally occurring instances in which tRNA genes and pol II promoters are juxtaposed, we examined the sigma and Ty3 elements. This class of retrotransposons is always found integrated immediately upstream of different tRNA genes. Weakening tRNA gene transcription by means of a temperature-sensitive mutation in RNA pol III increases the pheromone-inducible expression of sigma and Ty3 elements up to 60-fold.

Neonatal liver failure was evaluated in two infants. Neither infant had evidence of congenital infection, galactosemia, alpha 1-antitrypsin deficiency, tyrosinemia, Zellweger syndrome, or hemophagocytic lymphohistiocytosis. Abnormal levels of iron were detected in the minor salivary glands of the first infant and in the explanted liver of the second. Analyses of urinary bile salts by fast-atom bombardment ionization mass spectrometry and gas chromatography-mass spectrometry revealed a paucity of primary bile acids and a predominance of 7 alpha-hydroxy-3-oxo-4-cholenoic and 7 alpha,12 alpha-dihydroxy-3-oxo-4-cholenoic acids. These findings are consistent with delta 4-3-oxosteroid 5 beta-reductase deficiency, a primary genetic defect in bile acid synthesis. Postmortem evaluation of the first infant revealed significant iron deposition in the liver, pancreas, thyroid, adrenal glands, myocardium, stomach, and submucosal glands of the respiratory tract. In both infants examination of the liver revealed extensive loss of hepatic parenchyma. These cases expand the clinical spectrum of bile acid metabolism defects to include neonatal liver failure with associated hemochromatosis.

It has previously been shown that cDNA hybridization selection can identify and recover novel genes from large cloned genomic DNA such as cosmids or YACs. In an effort to identify candidate genes for hemochromatosis, this technique was applied to a 320-kb YAC containing the HLA-A gene. A short fragment cDNA library derived from human duodenum was selected with the YAC DNA. Ten novel gene fragments were isolated, characterized, and localized on the physical map of the YAC.

The hemochromatosis gene (HFE) maps to 6p21.3 and is less than 1 cM from the HLA class I genes; however, the precise physical location of the gene has remained elusive and controversial. The unambiguous identification of a crossover event within hemochromatosis families is very difficult; it is particularly hampered by the variability of the phenotypic expression as well as by the sex- and age-related penetrance of the disease. For these practical considerations, traditional linkage analysis could prove of limited value in further refining the extrapolated physical position of HFE. We therefore embarked upon a linkage-disequilibrium analysis of HFE and normal chromosomes from the Brittany population. In the present report, 66 hemochromatosis families yielding 151 hemochromatosis chromosomes and 182 normal chromosomes were RFLP-typed with a battery of probes, including two newly derived polymorphic markers from the 6.7 and HLA-F loci located 150 and 250 kb telomeric to HLA-A, respectively. The results suggest a strong peak of existing linkage disequilibrium focused within the i82-to-6.7 interval (approximately 250 kb). The zone of linkage disequilibrium is flanked by the i97 locus, positioned 30 kb proximal to i82, and the HLA-F gene, found 250 kb distal to HLA-A, markers of which display no significant association with HFE. These data support the possibility that HFE resides within the 400-kb expanse of DNA between i97 and HLA-F. Alternatively, the very tight association of HLA-A3 and allele 1 of the 6.7 locus, both of which are comprised by the major ancestral or founder HFE haplotype in Brittany, supports the possibility that the disease gene may reside immediately telomeric to the 6.7 locus within the linkage-disequilibrium zone. Additionally, hemochromatosis haplotypes possessing HLA-A11 and the low-frequency HLA-F polymorphism (allele 2) are supportive of a separate founder chromosome containing a second, independently arising mutant allele. Overall, the establishment of a likely "hemochromatosis critical region" centromeric boundary and the identification of a linkage-disequilibrium zone both significantly contribute to a reduction in the amount of DNA required to be searched for novel coding sequences constituting the HFE defect.