Biomedical subjects

T Barna

Publications and source records attributed to T Barna.

12 recordsLinked to original sources

PubMed2003

Experimental examination of the healing process of telescopic esophageal anastomosis.

The basis of telescopic anastomosis is old, only the practical details of it have changed and improved. The telescopic anastomosis technique is successfully applied in our practice for reconstruction of gastrectomy and esophageal resection. The reason for this study was that data about the healing process of telescopic anastomosis had not been found in the literature. We used four groups of mongrel dogs for our experiments: Group A (n = 3) received 20 mm-long invaginations with a survival time of 7 days; Group B (n = 3) received 10 mm-long invaginations with a survival time of 21 days; Group C (n = 3) received 20 mm-long invaginations with a survival time of 21 days; Group D (n = 3) received 30 mm-long invaginations with a survival time of 21 days. At the end of the above survival times we removed the anastomosing area, measured the bursting pressures and performed morphological and histological examinations. In each case we also performed an anastomosis exactly the same as a completely healed anastomosis and its pressure tolerance was measured (0 day). The pressure tolerance within the anastomosis rises gradually and independently of the length of the invaginated esophageal part. Anastomosis leakage did not occur. The invaginated esophageal part did not suffer any damage. The muscular wall of the intragastric part of the esophagus became covered by the mucosa of the stomach during the healing process and it joined with the esophageal mucosa at the edge of the free end of the esophagus.

Anastomosis, Surgical↗

PubMed2003

Operation technique and healing process of telescopic ileocolostomy in dogs.

The healing process of telescopic anastomoses was found in an animal experiment with 12 mongrel dogs. After the division of vessels an ileal segment of different length was invaginated into the lumen of the colon using single-layer interrupted sutures. The following four groups were used: Group A (n = 3): end-to-side ileocolostomy, single-layer interrupted suture (invagination length: 0 mm), survival time: 21 days. Group B (n = 3): invagination length: 20 mm, survival time: 7 days. Group C (n = 3): invagination length: 10 mm, survival time: 21 days. Group D (n = 3): invagination length: 20 mm, survival time: 21 days. At the end of the above survival times the anastomosis area was removed. The bursting pressure was measured and morphological as well as histological examinations were performed. In each case the 0-day look-alikes of anastomoses were performed using the remnant bowels, and bursting pressure measurements were done on these models as well. Anastomosis leakage did not occur. The serosal layer of the intracolonic part of the ileum disappeared during the healing process. The free surface of the intracolonic ileal segment became covered by the sliding mucosa of the colon and the prolapsing mucosa of the ileum. The following could be concluded after the experiments: The inner pressure tolerance of a telescopic ileocolostomy promptly after preparation is better than in case of another single-layer anastomosis. This fact results in increased safety against leakage on the first postoperative days. The inner pressure tolerance of the telescopic ileocolostomy increases during the healing process and it does not depend on the length of the invaginated part (0 day-20 mm: 56 mmHg +/- 6, Group A: 252 +/- 39, Group B: 154 +/- 19, Group C: 249 +/- 20, Group D: 298 +/- 2). There is no difference in pressure tolerance between the telescopic and the end-to-side single-layer interrupted anastomoses after the healing process. The invaginated section within the lumen of the large intestine does not suffer ischaemic or any other kind of damage. This inexpensive and simple anastomosis technique could be useful in the veterinary surgical practice as well.

Anastomosis, Surgical↗

PubMed2002

The role of mycorrhizae in afforestation (a review).

Hungary is facing to perform intensive afforestation. New forests will be planted on dry, poorly fertile soils nonprofitable for agricultural use. Applying artificially mycorrhized seedlings may considerably increase the effectivity of afforestation and decrease costs.

Conservation of Natural Resources↗

PubMed2001

Effects of environment on flavin reactivity in morphinone reductase: analysis of enzymes displaying differential charge near the N-1 atom and C-2 carbonyl region of the active-site flavin.

The side chain of residue Arg(238) in morphinone reductase (MR) is located close to the N-1/C-2 carbonyl region of the flavin isoalloxazine ring. During enzyme reduction negative charge develops in this region of the flavin. The positioning of a positively charged side chain in the N-1/C-2 carbonyl region of protein-bound flavin is common to many flavoprotein enzymes. To assess the contribution made by Arg(238) in stabilizing the reduced flavin in MR we isolated three mutant forms of the enzyme in which the position of the positively charged side chain was retracted from the N-1/C-2 carbonyl region (Arg(238)-->Lys), the positive charge was removed (Arg(238)-->Met) or the charge was reversed (Arg(238)-->Glu). Each mutant enzyme retains flavin in its active site. Potentiometric studies of the flavin in the wild-type and mutant forms of MR indicate that the flavin semiquinone is not populated to any appreciable extent. Reduction of the flavin in each enzyme is best described by a single Nernst function, and the values of the midpoint reduction potentials (E(12)) for each enzyme fall within the region of -247+/-10 mV. Stopped-flow studies of NADH binding to wild-type and mutant MR enzymes reveal differences in the kinetics of formation and decay of an enzyme-NADH charge-transfer complex, reflecting small perturbations in active-site geometry. Reduced rates of hydride transfer in the mutant enzymes are attributed to altered geometrical alignment of the nicotinamide coenzyme with FMN rather than major perturbations in reduction potential, and this is supported by an observed entropy-enthalpy compensation effect on the hydride transfer reaction throughout the series of enzymes. The data indicate, in contrast with dogma, that the presence of a positively charged side chain close to the N-1/C-2 carbonyl region of the flavin in MR is not required to stabilize the reduced flavin. This finding may have general implications for flavoenzyme catalysis, since it has generally been assumed that positive charge in this region has a stabilizing effect on the reduced form of flavin.

Bacterial Proteins↗

PubMed2000

[Role of surgery, its results and complications, in the combined treatment of primary gastric non-Hodgkin lymphoma].

During ten years 580 patients have been treated for gastric tumour in our department, 510 of them were operated on. Resection could be performed in 296 cases. 17 resections, 5.7 per cent of all were performed because of primary non-Hodgkin gastric lymphoma. No gastric lymphoma was found among the non-resected patients. The preoperative histological diagnosis was correct only in 8 cases. MALT origin could be proved in 5 patients. Synchronous adenocarcinoma and lymphoma was diagnosed in 2 patients. Staging was decided according to Lugano classification. There were six stage I, four stage II, and seven stage IV patients. 8 subtotal and 9 total gastrectomy was performed, 5 were extended and 2 were combined. R0 resection could be carried out in five stage I, two stage II and in one stage IV patient. We lost 2 patients in the postoperative period. Patients were treated with adjuvant chemotherapy (VEP, CHOP) except for 2 patients with low grade MALT lymphoma. The likelihood of one-year survival is 73 per cent, average two-year survival is 63 per cent. When the tumour is operable by total gastrectomy we suggest to perform splenectomy as well, despite of the fact that some postoperative complications can be related to it. We think it is reasonable to perform palliative resection in cases of locally extended stage IV tumours, which affect the patient's quality of life: to cease the pain, passage troubles, bleeding and to improve the conditions for adjuvant treatment.

Aged↗

PubMed1998

[Giant cell interstitial pneumonia].

GIP is a rarely occurring disorder. There is only few literature from its first description. Authors observed the course of GIP in the case of a 54 year old female patient in the form of bilateral disseminated microfocal pulmonary shadows, increased reticular outline with associated respiratory insufficiency. Open fine needle pulmonary biopsy proved giant cell desquamative alveolitis with help of light- and electronmicroscopical and histochemical examinations. Although possibility of exogenic, inhalative factor or/and infectious origin arose in causing the disease, disposition from the patient's actual immunological status could had helped the evolution of the disease. This fact seemed to be supported by the histologically proven associated dermatitis purpurica pigmentosa (Schamberg disease). With methylprednisolon therapy full radiological recovery occurred, while Schamberg disease was little influenced by the above mentioned therapy. The patient is pulmonologically symptom-free and without complaint after 1 year without any steroid-medication.

Cryptogenic Organizing Pneumonia↗

PubMed1997

Evidence that galactanase A from Pseudomonas fluorescens subspecies cellulosa is a retaining family 53 glycosyl hydrolase in which E161 and E270 are the catalytic residues.

A genomic library of Pseudomonas fluorescens subsp. cellulosa DNA was screened for galactanase-positive recombinants. The nine galactanase positive phage isolated contained the same galactanase gene designated galA. The deduced primary structure of the enzyme (galactanase A; GalA) encoded by galA had a Mr of 42 130 and exhibited significant sequence identity with a galactanase from Aspergillus aculeatus, placing GalA in glycosyl hydrolase family 53. The enzyme displayed properties typical of an endo-beta1, 4-galactanase and exhibited no activity against the other plant structural polysaccharides evaluated. Analysis of the stereochemical course of 2,4-dinitrophenyl-beta-galactobioside (2,4-DNPG2) hydrolysis by GalA indicated that the galactanase catalyzes the hydrolysis of glycosidic bonds by a double displacement general acid-base mechanism. Hydrophobic cluster analysis (HCA) suggested that family 53 enzymes are related to the GH-A clan of glycosyl hydrolases, which have an (alpha/beta)8 barrel structure. HCA also predicted that E161 and E270 were the acid-base and nucleophilic residues, respectively. Mutants of GalA in which E161 and E270 had been replaced with alanine residues were essentially inactive against galactan. Against 2,4-DNPG2, E161A exhibited a much lower Km and kcat than native GalA, while E270A was inactive against the substrate. Analysis of the pre-steady-state kinetics of 2,4-DNPG2 hydrolysis by E161A showed that there was an initial rapid release of 2,4-dinitrophenol (2,4-DNP), which then decayed to a slow steady-state rate of product formation. No pre-steady-state burst of 2,4-DNP release was observed with the wild-type enzyme. These data are consistent with the HCA prediction that E161 and E270 are the acid-base and nucleophilic catalytic residues of GalA, respectively.

Amino Acid Sequence↗

PubMed1992

Enhanced cerebral blood flow autoregulation in the newborn piglet by d-tubocurarine and pancuronium but not by vecuronium.

Neuromuscular blockers may affect cerebral blood flow (CBF) regulation in the newborn. We studied the effects of d-tubocurarine (0.1 mg.kg-1, n = 8), pancuronium (0.1 and 0.4 mg.kg-1, n = 6 and 7), and vecuronium (0.1 and 0.4 mg.kg-1, n = 6 and 7) on CBF measured over the same range of mean systemic blood pressure ([BP] 15-122 mmHg) in each group of newborn pigs; controls received normal saline (n = 7). The levels of BP during hypotension and hypertension were scaled at intervals of 5 +/- 1.6 mmHg and adjusted by inflating balloon-tipped catheters placed in the aorta. After saline, the low dose of pancuronium (0.1 mg.kg-1), and the two doses of vecuronium, CBF was constant over the BP range of 50-90 mmHg (r = -0.07-0.35, P greater than 0.20) but varied directly with BP beyond this range (tau = 0.38 - 0.60, P less than 0.05). In contrast, in pigs treated with d-tubocurarine and high-dose pancuronium, CBF remained constant from 35 to 122 mmHg of BP (r = 0.14 - 0.37, P greater than 0.10) and changed minimally (4-12%) with BP greater than 105 mmHg compared to the other groups (41-59%, P less than 0.01). When BP was reduced below 30 mmHg, CBF also decreased less (20-38%) in animals treated with d-tubocurarine and high dose-pancuronium than after the other treatments (58-67%, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Impact of prenatal testing on maternal-fetal bonding: chorionic villus sampling versus amniocentesis.

The process of maternal-fetal attachment, considered vital for normal infant development, begins during pregnancy and can be affected by a number of external factors. In this study the impact of prenatal testing on maternal-fetal bonding was evaluated in 253 women undergoing either first-trimester chorionic villus sampling (n = 101) or second-trimester genetic amniocentesis (n = 152). The women were evaluated by means of a modification of the Cranley Maternal-Fetal Attachment Scale, administered before and after the results of the prenatal diagnostic testing were made known to them (mean gestational ages of 10.6 and 15.7 weeks for the chorionic villus sampling group and 16.5 and 21.1 weeks for the amniocentesis group). The results showed: (1) that maternal-fetal attachment begins as early as 10 weeks' gestation and increases significantly as the pregnancy progresses, (2) that maternal-fetal attachment increases significantly, once the results are known to be normal, for both groups (p less than 0.001), (3) that this increase occurs about 5 weeks earlier for patients with chorionic villus sampling in comparison to those undergoing amniocentesis (p less than 0.001). Thus, with regard to the process of maternal-fetal attachment, first-trimester chorionic villus sampling appears to be preferable to second-trimester amniocentesis.

Amniocentesis↗

PubMed1991

Differences in the effects in the newborn piglet of various nonsteroidal antiinflammatory drugs on cerebral blood flow but not on cerebrovascular prostaglandins.

To characterize the role of prostaglandins (PG) in the regulation of basal cerebral blood flow (CBF) in the newborn, we determined the effects of four nonsteroidal antiinflammatory drugs, indomethacin (3 mg/kg, n = 8 and 10 mg/kg, n = 5), aspirin (65 mg/kg, n = 6), ibuprofen (30 mg/kg, n = 8), and naproxen (15 mg/kg, n = 6), on CBF, cerebral metabolism, and cerebrovascular PG in conscious 1- to 3-d-old piglets. Drugs and vehicle (n = 8) were injected i.v., and measurements were made 5 min before and 20 and 60 min after injections. Neither the vehicle nor any of the nonsteroidal antiinflammatory drugs exerted significant effects on mean arterial blood pressure and on blood gases and pH. All four drugs, with the exception of indomethacin at the lower dose (3 mg/kg), decreased PG to nearly undetectable levels within 20 min; the low dose of indomethacin caused a small decrease (18-32%) in PG at 60 min. However, the effects of these agents on CBF were diverse. CBF increased after the administration of aspirin, decreased to almost the same extent after both low and high doses of indomethacin, and did not change after the administration of ibuprofen and naproxen. Cerebral metabolic rate for oxygen was increased by aspirin but was unaltered by the other drugs. The data suggest that PG may not play a critical role in the regulation of basal CBF in the newborn animal and that certain nonsteroidal antiinflammatory drugs may have additional actions unrelated to the inhibition of PG synthesis.

Animals↗

PubMed1989

[Clinicopathology of bone metastases causing pathological fractures].

Of malignancies occurring in bones, metastatic tumours are the most frequent. Due to the increase of mean life span and to other factors the incidence of tumours is growing. Nevertheless, survival chances of patients suffering from tumours are also improving due to advance in diagnostics and to the application of complex therapy. These trends have substantially increased the number of recognized and manageable bone metastases. In general, life expectations of a tumour-patient are determined by the metastases therefore, the question of diagnostics and management of bone metastases is worth of special attention. Authors have performed a clinicopathological survey of patients of the past eight years who have suffered fracture due to bone metastases and were treated surgically. In one-third of the patients the primary tumour was unknown at the time of the fracture. On the basis of the histological pattern the detection of the parent-organ, particularly in adenocarcinomas, was not possible. Independently from the radiological appearance of the metastasis simultaneous osteogenesis and osteolysis were histologically observed.

Adult↗

PubMed1988

UV-induced photoproducts of 5-methylcytosine in a DNA sequence context.

In order to detect possible m5C photoproducts, highly purified rat liver DNA-cytosine methyltransferase was used to specifically generate m5C with a radioactive methyl group. When these DNAs were subjected to a large dose (10 kJ/m2) of 254 nm or 302 nm ultraviolet light (UVB) to enhance the yield, two labeled photoproducts were detected and isolated by reverse phase HPLC after formic acid hydrolysis. Further studies using acetone as a triplet state sensitizer and UVB irradiation suggested that photoproduct II was activated via a triplet state while the more polar photoproduct I was not. Photoreversion of the purified photoproducts with 10 kJ/m2 254 nm light demonstrated the following reactions: Photoproduct I regenerated m5C, while photoproduct II is split and regenerated m5C and photoproduct I. These results suggest that photoproduct I is monomeric while photoproduct II dimeric, and from the latter's elution position possibly a cyclobutyl type dimer arising from a reaction with an adjacent cytosine. Using d[TTG] and d[Cm5CG] as models of typical sequences, irradiation with 10 kJ/m2 254 nm or 302 nm, respectively, gave rise to a small component having altered mobility in sequencing gels. The altered mobility trinucleotides were resistant to degradation by PI and micrococcal nucleases as expected from photodimerization of the pyrimidine bases. Furthermore, oligonucleotide substrates containing m5C were synthesized and shown to be susceptible to T4 endonuclease v action at locations consistent with d[Cm5C] photodimer formation when irradiated in the UVB range.

5-Methylcytosine↗