Serum homocysteine concentrations have been shown to be a sensitive functional indicator of intracellular folate, vitamin B-12, and vitamin B-6 status. Chronic alcoholism is known to interfere with ...one-carbon metabolism, for which the above vitamins serve as coenzymes. In the present study, these vitamins were assessed in 32 chronic alcoholics and 31 healthy volunteers by measuring blood vitamin concentrations as well as serum homocysteine concentrations. In chronic alcoholics, serum pyridoxal 5'-phosphate and red blood cell folate concentrations were significantly lower than in the control subjects (P < 0.001 and P = 0.008, respectively). Mean serum homocysteine was twice as high in chronic alcoholics than in nondrinkers (P < 0.001). Beer consumers had significantly lower concentrations of homocysteine compared with drinkers of wine or spirits (P = 0.05). These results suggest that by interfering with folate or vitamin B-6 metabolism, chronic alcohol intake may impair the disposal of homocysteine through the transmethylation or transsulfuration pathways.
Background—Endoscopic diagnosis of short segments of Barrett’s epithelium (SSBE) is difficult and its meaning in terms of the presence of specialised columnar epithelium (SCE) has not been ...prospectively evaluated. Aims—To evaluate the prevalence of SCE in patients with an endoscopic diagnosis of SSBE and in individuals with normal appearing oesophagogastric junctions, and to compare the clinical characteristics of these two groups. Patients—Thirty one patients with an endoscopic diagnosis of short Barrett’s oesophagus, less than 3 cm in length (group A), and 44 consecutive patients with normal appearing oesophagogastric junctions (group B). Methods—Multiple biopsies were performed in suspicious epithelium and at the oesophagogastric junction in groups A and B, respectively. Results—Age and sex distribution were similar in both groups. Reflux symptoms were more frequent in group A (p<0.001), as were endoscopic and histological signs of oesophagitis (p<0.0001 and p=0.001, respectively). SCE was found in 61.3% of group A patients compared with 25% in group B (p<0.002), with men predominating in group A while women were more frequent in group B (p=0.02). The differences in reflux symptoms and endoscopic/histological oesophagitis remained significant. Conclusions—These results show that endoscopic diagnosis of SSBE is associated with a high prevalence of SCE, significantly higher than that found in normal appearing oesophagogastric junctions. Differences between patients with SCE in the two groups suggest they may represent two different entities.
Relationships of nutritional status with ethanol consumption and diet were studied in 33 chronic alcoholics with no clinical or laboratory evidence of liver disease.
Nutritional assessment included ...subjective global assessment, weight-height index, body mass index, and serum albumin measurements. Dietary intake included estimates of daily intake of substrates, folic acid, vitamins B1, B5, B6, and B12. Circulating concentrations of folate, pyridoxal-phosphate and vitamin B12 were evaluated as well.
Only 18.1% of patients were considered malnourished, with body mass indices lower than those with an average or good nutritional status (p < 0.0001). Body weight was under 90% of the ideal in 8/33 (24%) patients. Serum albumin values were within normal range in all patients. In terms of calories provided by nonalcoholic substrates, protein, or vitamin intake, we observed no differences between well and poorly nourished individuals. However, malnourished alcoholics consumed significantly more ethanol (p = 0.01) and an inverse correlation was found between ethanol intake and weight-height index (r = -0.35; p = 0.03). Low circulating concentrations of pyridoxal-phosphate and red blood cell folate were found in 51.5% and 60.6% of alcoholics, respectively. These were not correlated with vitamin dietary intake or ethanol consumption, but there was a trend toward malnourished patients to present lower concentrations of red blood cell folate (p = 0.13).
Although over malnutrition is infrequent in this group of chronic alcoholics, specific vitamin deficiencies are present in a substantial proportion of patients and are more likely related to alcohol consumption.
We have evaluated the effect of folate supplementation (5 mg/day) on global deoxyribonucleic acid (DNA) methylation status of the rectal mucosa of 20 patients with resected colonic adenomas in a ...prospective, controlled, cross-over study. Baseline values of DNA methylation were inversely correlated with caloric (P = 0.03) and fat intake (P = 0.05) and patients harbouring multiple polyps consumed significantly more calories (P = 0.0006), fat (P = 0.009) and carbohydrates (P = 0.009) as compared to patients having one single lesion. Folate supplementation resulted in a significant decrease of DNA hypomethylation in 7/20 patients (P = 0.05) which returned to previous values after placebo treatment. This effect was significantly correlated with number of polyps, with all the responders presenting one single lesion, whereas 8/13 of the non-responders had multiple ones (χ2 = 7.17, P = 0.007). In conclusion, folate supplementation may decrease degree of DNA hypomethylation, but only in patients with one single polyp. In those with multiple lesions, other nutritional factors such as caloric and fat intake, may be more determinant.
BACKGROUND: Global DNA hypomethylation has been found in the premalignant stages of some neoplasms and has been implicated as an important factor for tumour progression. AIMS: The aim of this study ...was to evaluate whether DNA hypomethylation occurs during the process of gastric carcinogenesis. METHODS: Gastric specimens were obtained from 49 patients and histologically classified as: normal 10, superficial gastritis 14, chronic atrophic gastritis with intestinal metaplasia 15, and intestinal type of gastric carcinoma 10. Global DNA methylation was assessed by incubating DNA with (3H)-S-adenosylmethionine and Sss1 methylase. A higher incorporation of (3H) methyl groups reflects a lower degree of intrinsic methylation. RESULTS: A graduated increase in (3H) methyl group incorporation into DNA was found over the range extending from normal gastric mucosa, to superficial gastritis and to chronic atrophic gastritis (136,556 (24,085) v 235,725 (38,636) v 400,998 (26,747 dpm/micrograms/DNA respectively; p = 0.0002). No further increase was found in specimens from patients with carcinoma. No differences were found between extent of DNA methylation in neoplastic or non-neoplastic mucosa from patients with gastric carcinoma. Hypomethylation of DNA increased substantially with severe atrophy (p = 0.01) or with type III intestinal metaplasia (p = 0.15). CONCLUSIONS: Global DNA hypomethylation occurs in the early stages of gastric carcinogenesis, and it may be a novel biomarker of gastric neoplasia, useful in monitoring the response to chemopreventive agents.
Microsatellite instability (MSI) detected in non-neoplastic mucosa of patients with ulcerative colitis has been ascribed to an excess of DNA damage associated with chronic inflammation. Folate ...deficiency, commonly found in patients with long-standing disease, could further contribute to this defect because folate is essential for DNA replication and repair. We evaluated MSI in the colonic mucosa of 26 patients with ulcerative colitis for >10 yr and 10 patients with Crohn's colitis and correlated MSI with folate status.
DNA was amplified using primers directed at nine different loci. Folate concentrations in serum, whole blood, and colonic mucosa were determined using the Lactobacillus casei assay.
MSI was found in 3/23 patients (13%) with ulcerative colitis and in none of the patients with Crohn's colitis. All three patients with MSI had inactive histological disease, whereas all patients with active disease were negative for MSI (p = 0.08). Serum, whole blood, and colonic concentrations of folate were 30-50% lower in patients with MSI (p > 0.05), and folate supplements had been administered less frequently during the past 5-yr (p = 0.06). One of the patients with MSI was randomized to receive folate 5 mg/d for 6 months, and a clear change in MSI pattern was observed in three of six markers.
A defect in DNA repair associated with a low folate status may be one additional cause for patients with ulcerative colitis exhibiting MSI in non-neoplastic mucosa.
BACKGROUND
DNA methylation and DNA cytometric parameters were evaluated in the rectal mucosa from patients with extensive and long‐standing ulcerative colitis.
METHODS
Twenty‐six patients with ...extensive disease for more than 7 years and 11 healthy controls were included. Global DNA methylation was assessed as the capacity of the DNA test to incorporate 3Hmethyl groups from 3H‐S‐adenosylmethionine in the presence of Sss1 methylase. A higher incorporation reflects a lower state of intrinsic methylation. DNA ploidy, S‐phase fraction, and proliferative index (PI = S + G2M) of the cell cycle were analyzed by flow cytometry.
RESULTS
Incorporation of the 3Hmethyl groups into DNA was 10‐fold higher in patients compared with controls (P < 0.001) and was significantly higher in patients with histologically active disease (P = 0.02). With regard to flow cytometry, all samples showed a diploid pattern, but S‐phase fraction and the proliferative index values were significantly increased in patients compared with controls (P = 0.0007 and P = 0.003, respectively). A positive correlation was found between S‐phase fraction and proliferative index and the number of exacerbations of the disease (P < 0.005), and there was a trend among those patients who had disease for longer than 20 years to present with increased cellular proliferation compared with those with a shorter evolution of disease (P > 0.05).
CONCLUSIONS
DNA hypomethylation and proliferative activity are increased in this group of patients, supporting the concept that their colonic mucosa undergoes epigenetic and kinetic changes that might predispose these individuals to develop colorectal neoplasms. However, it cannot be ruled out that these markers solely reflect hyperproliferation associated with active inflammation. Cancer 1996;78:2300‐6.
The Muir-Torre syndrome is a rare autosomal dominant disorder characterized by the association of visceral malignancies with typical skin lesions. This syndrome is now considered a subtype of the ...more common hereditary nonpolyposis colorectal cancer syndrome (HNPCC). This last condition has been ascribed to mutations in four mismatch repair genes, and similar mutations, mostly located at hMSH2 gene, are now being described in some Muir-Torre patients. We describe the case of a 64-yr-old woman with no family history of colorectal cancer, who developed two visceral malignancies belonging to the usual spectrum of hereditary nonpolyposis colorectal cancer (colon and stomach), beginning at age 41. She additionally developed several skin tumors, including multiple keratoacanthomas, thus fulfilling Muir-Torre diagnostic criteria. Because of her cutaneous phenotype, she was screened for DNA mismatch repair gene mutations by in vitro synthetized protein assay (IVSP) and a truncating mutation was identified at hMSH2. We further discuss the clinical significance of the Muir-Torre phenotype, the association of this syndrome with hMSH2 mutations and the important implications of genetic diagnosis for the patient and her offspring.
Background. Studies using DNA technology have reported the presence of human papillomavirus (HPV) DNA in esophageal carcinomas, suggesting that it could play a role in the pathogenesis of this tumor. ...In the present study, in addition to DNA from neoplasms, normal mucosa was screened for viral DNA, assuming that this would increase HPV detection substantially.
Methods. Seventeen patients with esophageal carcinoma and 10 control subjects were studied. In 8 of the patients, normal mucosa was also available. Polymerase chain reaction (PCR) was performed using primers for the E6 region of HPV‐16 and HPV‐18. Koilocytosis, a commonly accepted histopathologic marker of viral infection, was studied, and results were correlated with PCR findings.
Results. DNA from neoplastic lesions was positive for HPV‐16 and HPV‐18 in 8 of 16 (50%) and in 3 of 16 (18.8%), respectively. When tumor tissue and normal mucosa were available, PCR results were 3 of 8 (37.5%), 5 of 8 (62.5%), and 8 of 8 (100%) for HPV‐16, in tumor, normal mucosa, and both. For HPV‐18, results were 0 of 8 (0%), 5 of 8 (62.5%), and 5 of 8 (62.5%), respectively. In comparison with tumor samples, positivity in normal mucosa was increased for HPV‐18 and for both viral genotypes (P = 0.01). No amplification was obtained in the control group. Koilocytosis was present in 33% of the cases.
Conclusions. These results suggested a high prevalence of HPV in esophageal carcinoma. The detection rate is significantly higher in normal mucosa specimens, suggesting that infection probably antedates tumor development. Koilocytosis was substantially less sensitive than PCR. Cancer 1995; 76:1522–8.
Poly(ADP-ribose)polymerase (PARP) has been implicated in DNA repair mechanisms and the associated activity shown to markedly increase after DNA damage in carcinogen-treated cells. A defective DNA ...repair has been associated to the aetiology of human cancers. In order to assess the potential role of this enzyme in cellular response to DNA damage by gamma-radiation, we studied the activity of PARP in patients with familial adenomatous polyposis (FAP). We compared poly(ADP-ribose)polymerase activity by the rate of incorporation of radioactivity from 3Hadenine-NAD+ into acid-insoluble material in permeabilized leucocytes from FAP patients and healthy volunteers. Concomitantly, the intracellular levels of NAD+--the substrate for the PARP--and the reduced counterpart NADH were determined using an enzymatic cycling assay 30 min after 60Co gamma-ray cells irradiation. Our results demonstrate that a marked stimulation of PARP activity is produced upon radiation of the cells from healthy subjects but not in the FAP leucocytes, which concomitantly show a marked decrease in total NAD-/NADH content. Our observations point to a role of PARP in the repair of the gamma-radiation-induced DNA lesions through a mechanism that is impaired in the cells from FAP patients genetically predisposed to colon cancer. The differences observed in PARP activation by gamma-radiation in patients and healthy individuals could reflect the importance of PARP activity dependent on treatment with gamma-rays. The absence of this response in FAP patients would seem to suggest a possible defect in the role of PARP in radiation-induced DNA repair in this cancer-prone disease.
PDF
