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Biomedical subjects

J Chojnacki

Publications and source records attributed to J Chojnacki.

At least 19 recordsLinked to original sources
PubMed2006

Nocturnal secretion of melatonin in patients with upper digestive tract disorders.

Recently, the results of many experimental investigations have shown that melatonin possesses gastroprotective properties. On the other hand its role in pathogenesis of upper digestive tract diseases in man still remains unclear. The aim of the study was to investigate nocturnal secretion of melatonin in patients with functional and organic diseases of the upper part of digestive tract. The investigations were carried out in 149 persons, aged 21-51 years, including healthy subjects (group I, n=30), and patients with non-erosive gastroduodenal reflux (NERD, group II, n=24), with gastroesophageal reflux disease (GERD, group III, n=25), with functional dyspepsia (FD, according to the Rome III Criteria, group IV, n=36) and with recurrent duodenal ulcer (DUD, group V, n=34). Diagnoses were established on the basis of endoscopic imaging and histological examination, 24-hour pH-metry and laboratory tests. Melatonin serum concentration was measured with ELISA method. Blood samples were taken for examination in red-lighted room at 10 p.m. and on the following day at 2 and 6 a.m. The highest concentration of melatonin in all examined groups was determined at 2 a.m. The average melatonin concentration in healthy subjects was 34,7 +/- 4,8 pg/ml. In patients with GERD and DUD melatonin concentration was lower than in healthy subjects - 27,2 +/- 8,5 pg/ml and 25,5 +/- 6,2 pg/ml respectively (p < 0,05; p < 0,01). The highest concentration of melatonin was found in patients with NERD and FD - 43,2 +/- 10,8 pg/ml and 42,4 +/- 10,1 pg/ml (p < 0,01; p < 0,05). The findings of this study support the notion that melatonin exerts beneficial influences on the upper digestive tract. It is likely that high or relatively correct secretion of melatonin is sufficient to prevent peptic changes in esophageal and duodenal mucosa.

Adult↗
PubMed2005

A hydrophobic domain in the large envelope protein is essential for fusion of duck hepatitis B virus at the late endosome.

The duck hepatitis B virus (DHBV) envelope is comprised of two transmembrane (TM) proteins, the large (L) and the small (S), that assemble into virions and subviral particles. Secondary-structure predictions indicate that L and S have three alpha-helical, membrane-spanning domains, with TM1 predicted to act as the fusion peptide following endocytosis of DHBV into the hepatocyte. We used bafilomycin A1 during infection of primary duck hepatocytes to show that DHBV must be trafficked from the early to the late endosome for fusion to occur. Alanine substitution mutations in TM1 of L and S, which lowered TM1 hydrophobicity, were used to examine the role of TM1 in infectivity. The high hydrophobicity of the TM1 domain of L, but not of S, was shown to be essential for virus infection at a step downstream of receptor binding and virus internalization. Using wild-type and mutant synthetic peptides, we demonstrate that the hydrophobicity of this domain is required for the aggregation and the lipid mixing of phospholipid vesicles, supporting the role of TM1 as the fusion peptide. While lipid mixing occurred at pH 7, the kinetics of insertion of the fusion peptide was increased at pH 5, consistent with the location of DHBV in the late-endosome compartment and previous studies of the nonessential role of low pH for infectivity. Exchange of the TM1 of DHBV with that of hepatitis B virus yielded functional, infectious DHBV particles, suggesting that TM1 of all of the hepadnaviruses act similarly in the fusion mechanism.

Animals↗
PubMed2001

[Laryngeal mask of gastroesophageal reflux disease].

Gastroesophageal reflux disease has become a serious problem not only for general practitioners but for other specialists as well. It is caused by the fact that its clinical picture and symptomatology are very rich. Beside characteristic symptoms such as: heartburn, eructation, gastric contents reflux, epigastric burning or dysphagia, there may appear extroesophageal symptoms (frequently as single or leading ones). It is generally though that the above symptoms result from the direct effect of gastric contents on throat and larynx and/or through vagus nerve. Direct effect of hydrochloric acid and other gastric juice components on larynx may be the cause of subglottic laryngostenosis, neoplastic transformation and development of squamous cell carcinoma. This, it may be concluded that gastroesophageal reflux disease should be in the sphere of interest of laryngologists as well as gastroenterologists. Cooperation of these specialists is particularly useful as it quickens the choice of proper diagnostic procedure and an introduction of an appropriate therapeutic treatment.

Gastroenterology↗
PubMed1999

[Effect of prokinetic drugs inhibiting dopaminergic system on gallbladder motility in subjects with duodenal ulcer].

The purpose of this study was to determine the effect prokinetic drugs inhibiting dopaminergic receptors on gallbladder volume in normal conditions. The study comprised 90 males, aged 20-26 years with duodenal ulcer disease in remission alloted into 3 groups, 30 subject each. The gallbladder volume was determined in group I after placebo or 10 and 20 mg or metoclopramide administration; in group II: placebo or 10 and 20 mg of domperidone and in group III after placebo or 50 and 100 mg of sulphiride administration. Gallbladder motility was assessed ultrasonographically from 15 minutes to 2 hours since placebo or drug administration. The effect of the studied prokinetic drugs in fasting on gallbladder motility was differentiated after metoclopramide no significant changes in gallbladder volume were observed; after domperidone in the dose of 20 mg a slight decrease of gallbladder volume was found, whereas after sulphiryde statistically significant decrease was detected.

Adult↗
PubMed1999

[The advanced stomach cancer].

In the years 1993 to 1997, 106 patients with gastric carcinoma were treated. The age of patients ranged from 24 to 90 years. There were 73 males and 33 females. Variant advancement of gastric carcinoma was diagnosed in the patients: 29 had III grade and 77 IV grade according to TNM. The following resections of the stomach were performed: total in 38 (46%), subtotal or partial 45 (54%). While the remaining 23 patients had other operative procedures. The resection rate increased from 13% to 54%. Chemotherapy was also used. 53 patients died. The authors conclude that the increase in surgical radicalness and application of aggressive chemotherapy are the methods improving the results in gastric carcinoma.

Aged↗
PubMed1995

Oxygen metabolism in blood of patients with gastric and duodenal ulcer disease.

Among multiagent mechanisms causing peptic ulcer disease, oxygen free radicals hypothesis is reasonable. Our investigation concerned the determination of oxygen free radicals generation lipid peroxidation and enzymatic antioxidative defense in blood of patients with peptic ulcer disease. The examinations were performed in 79 males, non-smokers, aged 20-51 with peptic ulcer disease, clinically diagnosed as gastric or duodenal ulcer. Biochemical investigations were carried out on blood platelets obtained from venous blood according to the centrifugation fractionation technique. Superoxide dismutase (CuZn-SOD) (EC 1.15.1.1.) activity and malonyl dialdehyde (MDA) concentration were determined according to Misra and Fridovich (1972) and Placer et al (1966) methods, respectively. Oxygen free radicals as the superoxide anion O2- generation in blood according to Bellavite et al. (1983) method was determined. The results indicate that patients with peptic ulcer disease have a higher level of malonyl dialdehyde in blood platelets, whereas the superoxide dismutase activity is significantly decreased in comparison with the control group. Oxygen free radicals generation both in patients with peptic ulcer disease as in healthy men is maintained at normal level. Our data suggest that in spite of similar range of oxygen free radicals generation both in patients with peptic ulcer disease and healthy men, the injury to patients by superoxide anion is more destructive and harmful to cells, because the enzymatic antioxidative defense is decreased. The increase of lipid peroxidation in patients with peptic ulcer disease also supports this conclusion.

Adult↗
PubMed1992

Some ultrastructural aspects of Helicobacter pylori gastritis.

Ultrastructural examinations of biopsy specimens of the gastric mucosa were performed in 20 patients with chronic gastritis proven by endoscopy and microscopy. The presence of the Helicobacter pylori bacteria was found in close contact with epithelial cells of the antrum and corpus of the stomach. The bacteria were not present in the areas of frequently observed intestinal metaplasia. There were ultrastructural changes on the surface and within the cytoplasm of the epithelial mucous cells, which indicated their disturbed metabolism.

Chronic Disease↗
PubMed1989

[Effectiveness of sucralfate in the treatment of gastric ulcer in women during menopause--comparison with cimetidine].

The reported study was done in 60 women aged 44 to 60 years during menopause. In group I (n = 30) sucralfate was used (Venter, Krka) in doses of 1.0 g daily. The rate of symptom disappearance and ulcer healing and the frequency of recurrences were assessed. It was observed that the rate of ulcer healing after sucralfat was higher and recurrences were leas frequent.

Adult↗
PubMed1989

[Morphological and functional condition of the stomach in multiple sclerosis patients treated with prednisone].

In 30 patients with multiple sclerosis treated with prednisone the morphological status of the gastric mucosa was assessed endoscopically and microscopically, and the secretory function of the stomach was studied determining hydrophloric acid, sialic acid and total glycoproteins in gastric juice before and after 6 weeks of prednisone treatment. After the treatment in 9 cases the symptoms and signs of gastritis were exacerbated, in 7 cases they were alleviated, and in gastric juice secretion of sialic acid was reduced in most cases.

Adult↗