Biomedical subjects
Publications and source records attributed to G Tóth.
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From the condensation reaction of O-methylbutyrolactim (2), O-methylvalerolactim (3), O-methylcaprolactim (4) and O-methyl-4-t-butylcaprolactim (5) with ethyl 6,7-dimethoxy-alpha-[1-(1,2,3,4-tetrahydro-isoquinolyl)] acetate (1), 8,13-diaza-2,3-dimethoxygona-1,3,5(10),9(11)-tetraen-1 2-one (6) D-homo-derivatives (7-9), and medium-sized ring cyclic diamides (10,11) were obtained. The stereoselective reduction of compounds 6-9 by Adam's platinum catalyst afforded 8,13-diaza-2,3-dimethoxygona-1,3,5(10)-trien-12-one (12) and its D-homo derivatives (13-15). The structures of the compounds obtained were established by NMR and X-ray crystallographic analyses.
Crohn's disease (CD) is frequently complicated by various nutritional disturbances. Although it is important to correct these disturbances, the nutritional status of CD patients has been poorly documented, especially concerning vitamin status. The aims of this study were (a) to measure the serum concentrations of vitamin A and six other carotenoids (lutein, zeaxanthin, alpha-, beta-carotene, alpha-, beta-cryptoxanthin) in patients with CD and to compare them with those in healthy controls and (b) to follow the changes of serum carotenoid levels in CD patients during treatment. Twenty-eight patients with CD and 23 healthy persons were included in this study. The results of twelve patients were followed up through one year. The patients were free of any nutritional treatment. The serum concentrations of carotenoids were measured with high-pressure liquid chromatography (HPLC). The serum concentrations of five carotenoids were significantly lower in the patients than in the controls (vitamin A, zeaxanthin: P < 0.001; alpha-, beta-carotene: P < 0.01; lutein: P < 0.05). The carotenoid status of the followed patients advanced to the normal range, but this increase was not significant. These findings suggest that there is a deficiency of vitamin A and its provitamins in Crohn' s disease prior to treatment. However, because we did not evaluate the vitamin intake in this study, we could not conclude which of the factors--poor intake, increased requirement, or malabsorption--was more important in decreasing of carotenoid levels.
UNLABELLED: The serum levels of carotenoids (vitamin A, lutein, zeaxanthin, alfa- and beta cryptoxanthin, alfa- and beta-carotene) were measured in healthy persons (n=40) and in 98 patients with different malignant gastrointestinal diseases (44 patients with colon adenocarcinoma, 21 with gastric cancer, 15 with hepatocellular adenocarcinoma, 10 patients with pancreas adenocarcinoma and eight patients with esophagus cancer). The serum levels of carotenoids were measured with high-pressure liquid chromatography. The sera of the patients were taken at the time of the diagnosis. RESULTS: the measurements indicated that (1) the serum level of vitamin A and zeaxanthin were significantly lower in all of these groups (except of pancreas adenocarcinoma), but the extent of the A decrease was different in the patients with different types of gastrointestinal malignancy. The serum level of vitamin A was in the healthy subjects 2.072+/-0.332 mmol/l and in the case of gastrointestinal malignancies was 0.77+/-0.14 mmol/l (P<0.001) The serum level of zeaxanthin was in the healthy subjects 0.143+/-0.057 mmol/l and at the malignancies was 0.042+/-0.014 mmol/l (P<0.01). (2) There were no significant differences in the serum levels of other carotenoids in the checked groups. (3) The serum level of cholesterol, total protein, albumin and haemoglobin were in the normal range in these patients. These results indicate that the carotenoids may be responsible nutritional factors (as nutritional scavengers) in the development of different malignant diseases. This supposed role in the carcinogenesis does not depend fully on the vitamin A activity.
BACKGROUND: Tumor, calor, dolor, pallor and functio laesa are together involved in the different acute and chronic inflammatory processes. The processes involved in the inflammation are determined by differently acquired and hereditary factors. Recently the presence of a new genetic marker (Leiden point mutation) was found in Crohn's disease and ulcerative colitis. On the other hand, the GI mucosal integrity was proven on gastrointestinal mucosal damage to be produced by different chemicals, xenobiotics, drugs. In human observations, the serum level of retinoids (vitamin A, lutein, zeaxanthin, alpha-, beta-carotene) was proven in patients with chronic gastrointestinal inflammatory bowel disease. The aims of this study were (1) to measure the prevalence of Leiden mutation; (2) to identify the changes in the serum retinoid level in patients with Helicobacter pylori infection of the stomach (n=24), hepatitis C infection (n=75), ileitis terminalis (Crohn's disease; n=49), ulcerative colitis (n=35), colon polyposis (n=59) and adenocarcinoma in colon polyps (n=9), and 57 healthy persons were used in the control group; (3) to compare the directions of the changes in the measured parameters in the acute (H. pylori and hepatitis C infections), chronic (ileitis terminalis, ulcerative colitis) GI inflammatory diseases and in colon polyposis without and with malignisation. METHODS: The Leiden mutation was measured by the method of polymerase chain reaction, the retinoid level in the patient's serum was measured by high liquid cromathografic method (HPCL). RESULTS: (1) It has been found that the prevalence of Leiden mutation increased significantly in patients with ileitis terminalis (P<0.001), ulcerative colitis (P<0.001), colon polyposis (P<0.001) and with colon polyps with malignisation (P<0.01). (2) Serum level of vitamin A and zeaxantin were decreased significantly in all group of patients except for the group with H. pylori infections. (3) alpha- and beta-carotenes were found to be practically at the same level as those in the control groups, except in patients of colon polyps with malignisation. (4) The vitamin A, lutein, zeaxantin, alpha- and beta-carotenes were decreased in patients with ileitis terminalis. CONCLUSIONS: (1) The essential role of retinoids (carotenoids) as environmental factors are suggested for keeping GI mucosal integrity in human healthy subjects and patients. (2) Leiden mutation, as a genetic marker, can be used in the screening of patients with ileitis terminalis, ulcerative colitis and colon polyposis (without and with malignisation). (3) An opposite direction can be found between the increased prevalence of Leiden mutation and decrease of serum levels of retinoids in group of patients with ileitis terminalis, ulcerative colitis and colon polyposis (without and with malignisation).
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Oxytocin (OT) itself and the sensitivity of the uterus to OT play a crucial role in the initiation of both normal and pathologically early delivery. It recognition of the complex mechanism of action suggests that specific OT antagonists are of therapeutic value in postponing early contractions. In this study neurohypophyseal hormone analogues containing Sar in position 7, Arg in position 8, and various conformationally restricted or bulky derivatives of phenilalanine and tryptophan amino acids in position 2 were prepared to design more potent and selective OT antagonists. We determined the ligand-receptor binding characteristics of these newly synthetized peptides in the presence of [3H]oxytocin and [3H]vasopressin on isolated guinea-pig uterus, rat liver and kidney inner medulla plasma membranes. In the case of each peptides we calculated the Ki values and the selectivity ratio. The binding to the OT receptor was dramatically decreased for the Trp-derivatives containing analogues, while the Phe-derivatives containing analogues displayed a relatively high receptor affinity and have a relatively high OT/VP1 receptor selectivity.
BOC-Tyr-Pro-Gly-Phe-Leu-Thr(OtBu) is a potent, highly delta-opioid receptor-selective competitive antagonist, the Ke values in the mouse vas deferens in vitro assay against [D-Ala2, D-Leu5]-enkephalin [D-Pen2, D-Pen5]enkephalin and deltorphin-II being 39.5, 38.7 and 27.3 nM, respectively, whereas those against [D-Ala2, MePhe4-Gly5-ol]enkephalin (DAMGO) and ethylketocyclazocine in the guinea-pig ileum are 368,000 and > 200,000 nM, giving a higher than 9000-fold delta- vs mu- and a higher than 5000-fold delta- vs kappa-selectivity ratio. The Ki values against various labeled delta-ligands in the rat brain receptor binding assay were in the 300-1000 nM range, whereas the Ki against [3H]-DAMGO was higher than 30,000 nM. The striking discrepancies between bioassay and receptor binding data show another aspect of already recognized differences of mouse vas deferens and rat brain delta-receptors. With the aim of producing a delta-selective affinity ligand, we synthesized the BOC-Mel1 derivative; however, there was a 175-fold loss of delta-receptor affinity in the bioassay and no indication of an irreversible interaction, but a delta-agonist effect appeared in spite of nonprotonated nitrogen. The corresponding BOC-Phe1 derivative had a 10 times higher affinity and, apparently, no agonist activity.