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Biomedical subjects

F Kovács

Publications and source records attributed to F Kovács.

At least 19 recordsLinked to original sources
PubMed2003

Effect of induction of late embryonic mortality on plasma profiles of pregnancy associated glycoprotein 1 in heifers.

Inoculation with Actinomyces pyogenes and administration of prostaglandin (PG)F(2alpha) were used to induce late embryonic mortality (LEM) in heifers (n=8) on Days 30-38 of pregnancy in order to compare the profile for bovine pregnancy associated glycoprotein 1 (PAG1), progesterone and 15-keto-13,14-dihydro-PGF(2alpha) (PGFM). Two pregnant heifers were used as controls. Inoculation into the uterine body caused LEM, as established by ultrasonography in each heifer within 24h of treatment. When the inoculum was injected into the first part of the cervix, LEM occurred in one of two heifers (Heifer A) between 48 and 72 h after treatment. Similarly, PGF(2alpha) treatment caused LEM in three of four heifers. In six of eight heifers, PAG1 started to decrease steadily when it was accompanied by the subsequent death of the embryo. Inoculation through the cervix caused luteolysis in three of four heifers within 6-10 days after induction. After induction of LEM, PGFM concentrations showed a two to 3.8 fold increase in three of four heifers during the following six days, and from that time changed within normal ranges. The results of this study indicate that a PAG1 assay may provide an alternative method to ultrasonography for determining LEM in the cow.

Abortion, Veterinary↗
PubMed2003

Effect of dietary fumonisin B1 on certain immune parameters of weaned pigs.

Only few data are available on the effect of fumonisins on the immune response. The aim of the present study was to examine whether dietary fumonisin B1 (FB1) has any effect on the humoral and cellular immune response in weaned pigs, depending on the dose and the time of toxin exposure. Fusarium moniliforme fungal culture was added to the experimental animals' diet to ensure an FB1 intake of 1, 5 and 10 ppm (first experiment) or 100 mg per animal per day (second experiment). The control animals were fed a toxin-free diet. In order to determine the immune response, the animals were vaccinated against Aujeszky's disease with inactivated vaccine (Aujesping K, Phylaxia-Sanofi, Budapest, Hungary). Specific and nonspecific in vitro cellular immune response was measured by the lymphocyte stimulation test (LST) induced by PHA-P, Con A, LPS and inactivated suspension of the Aujeszky's disease virus. Humoral immune response, e.g. specific antibody titre, was measured by the virus neutralisation (VN) test. None of the immunological parameters examined showed significant differences between groups. It could be concluded that fumonisin B1 had no significant effect on the humoral and cellular specific and nonspecific immune response when fed in a high dose (100 mg/animal/day for 8 days) or in a low concentration even for a longer period (1, 5 and 10 ppm for 3-4 months).

Animal Feed↗
PubMed2003

Turbinate atrophy evaluation in pigs by computed tomography.

Computed tomography (CT), a non-invasive visualisation technique was applied for imaging the bony structures of the nasal cavity of pigs, and compared to the traditional scoring system of turbinate atrophy in swine. Twenty-three 27-week-old pigs representing various stages of turbinate atrophy were used. Nasal structures were visually scored on CT scans and transversal cuts of the noses at the level of the first upper premolar teeth using the same scoring system in both cases. A tissue/air area ratio was also determined based on density differences. A highly significant correlation was found between visual scoring of CT images and transversal cuts of pig noses (r = 0.98, p < 0.0001) as well as between visual scoring of CT images and tissue/air area ratio determination (r = -0.82, p < 0.0001).

Animals↗
PubMed2002

Evaluation of vaccines for atrophic rhinitis--a comparison of three challenge models.

We compared three challenge models for the assessment of atrophic rhinitis (AR) vaccines: combined infection with Bordetella bronchiseptica (Bb) and Pasteurella multocida (Pm); application of acetic acid (AA) to the nasal mucosa followed by Pm infection; and Bb infection alone. Two vaccines were tested using standardized criteria, notably nasal lesion scores. The vaccines provided different levels of protection in the Bb and the AA/Pm challenges, but were similar in the combined (Bb/Pm) challenge. It is clear that the AA/Pm model shows the protective value of only the Pm component, whereas the single Bb challenge reflects the protective value merely of the Bb component of a combined vaccine. These results suggest that the best assessment of protection is provided if the two specific challenges are performed separately.

Acetic Acid↗
PubMed2002

Effects of prolonged exposure to low-dose fumonisin B1 in pigs.

From the point of view of human exposure, fumonisins (FB1, FB2, FB1, FB4), a relatively recently (1988) discovered and identified group of mycotoxins, represent one of the five most important mycotoxin groups causing human disease. In an earlier experiment studying the effects of relatively low doses (10, 20 and 40 p.p.m.) of FB1 in weaned piglets, it was established that the 4-week feeding of 10 p.p.m. (mg/kg feed) FB1 produced mild pulmonary oedema. This suggested the importance of studies with even lower doses of the toxin to determine the tolerable limits. The objective of this experiment was therefore to study the effects of prolonged (8-week) exposure to still lower concentrations (0, 1, 5 and 10 mg/kg feed) of FB1. The 8-week feeding of FB1 in low concentrations (1-10 p.p.m.) did not cause clinical signs and significant performance impairment in pigs, but rendered irreversible the chronic changes that had already developed in the animals in a dose-dependent manner. Dissection revealed pathological alterations of the lungs in one of the animals given 1 p.p.m. (n = 4), in two animals exposed to 5 p.p.m. (n = 5), and in three animals given 10 p.p.m. (n = 4). In all three treatment groups, proliferation of the connective tissue fibres, primarily of those around the lymphatic vessels, in the subpleural and interlobular connective tissue of the lungs, extending to the peribronchial and peribronchiolar areas, was seen. The results of this experiment call attention to the risk of prolonged low-dose toxin exposure, which has very important public health implications.

Animal Feed↗
PubMed2001

[Partial replacement of the trachea with jejunal autograft in the dog].

Extensive lesions of the cervical trachea can occur as a result of malformation, inflammation, tumor disease or trauma. If a short segment of the trachea is resected primary anastomosis may be possible. The problem of how to treat lesions longer than 50% of total tracheal length is still unresolved. The aim of our study was to clarify the possible use and limitations of small bowel interposition for tracheal replacement in veterinary model. We resected 6 cm of the cervical trachea of 5 adult mongrel dogs. Autolog jejunum free flap was used for replacement. The wall of the implant was supported with 5 polytetrafluoroethylene rings placed on the outer surface of the bowel perpendicular to its axis. We performed the surgery in two stages. Intraoperative tracheostomy was necessary in every case. The tracheal tube extended through the whole length of the implant. The survivals, the viability of the graft and complications were examined. The length of survival ranged between 18 h and 72 h. In one case obstruction of the tracheal tube occurred, in 3 cases the micro vessel anastomosis of the graft thrombosed, in one case both complications developed. In our experience use of the small bowel flap was complicated with fatal technical difficulties. The micro vessel anastomosis proved to be highly risky. Further investigations are needed to improve the results with this method.

Animals↗
PubMed2000

Preliminary communication: examination of the harmful effect to fetuses of fumonisin B(1) in pregnant sows.

Three sows were fed a diet mixed with Fusarium moniliforme fungal culture from the 107th day of pregnancy until parturition. Fumonisin B(1) toxin was administered to two sows (sows 1 and 2) in a daily dose of 300 mg for an additional 7 days subsequent to parturition, i.e., for a total of 14-16 days. The third sow (No. 3) was given the toxin in the same daily dose only until parturition, i.e., for 7 days in total. There were no symptoms observed in any of the sows. Two piglets were taken from each of the three sows and sacrificed immediately after parturition, i.e., prior to the first suckling. After 24 h, two additional piglets were taken for slaughter from each of the litters, which by then had access to colostrum. Finally, on the 7th day postparturition another two piglets per litter were sacrificed and material obtained from them was processed for examination. It was established that fumonisin B(1) present in the Fusarium moniliforme culture resulted in damage to the fetuses in utero. Of the changes indicating toxic effect, intraalveolar, subpleural, and interstitial pulmonary edema of various degrees of severity could be detected in the piglets sacrificed immediately following parturition and before the first suckling. Pathological changes were observed in the histopathological sections of the liver, and increases in the activities of plasma aspartic acid transaminase (AST), gamma glutamyl transferase (GGT) and alkaline phosphatase (AKLP), higher than physiological levels were detected. The serum-free sphinganine/sphingosine ratio, considered a bioindicator of fumonisin B(1) toxicosis, varied in accordance with the degree of severity of the changes which occurred. The values obtained were found to be between 0.29 and 0.36 in the cases of severe pulmonary edema, and between 0.20 and 0.24 for the cases of mild pulmonary edema. In the piglets of the sows fed the toxin for an additional 7 days subsequent to parturition and which were born with severe pulmonary edema, mild pulmonary edema could be detected after colostrum suckling, 24 h, and 7 days after parturition. The SA/SO value of the serum in these two piglets was 0.19 and 0.20, while at the same time AST, GGT, and ALKP values higher than physiological levels were measured. In the milk samples taken from sows 1 and 2 and examined after 24 h and after 7 days FB(1) was detected in quantities of 18.0-27.5 ppb. There were no changes observed on the seventh day in the piglets of the third sow, the diet of which contained no toxin after parturition. However, as the piglets of the third sow demonstrated only mild effects of pulmonary edema it is not possible to establish with certainty a postpartum cause-effect relationship between fumonisin in colostrum and pulmonary edema.

Aging↗
PubMed2000

Experiment to determine limits of tolerance for fumonisin B1 in weaned piglets.

In Hungary almost 70% of mould-affected maize inspected since 1993 was found to be contaminated with fumonisin B1 (FB1) (mean 2.6-8.65 mg/kg; maximum 9.8-75.1 mg/kg), the degree of this contamination was found to increase from year to year (Fazekas et al., 1997b). In this experiment, in order to define tolerance limit values, the effect of exposing weaned piglets to FB1 in low doses over a 4-week period was examined. The experiment was performed with 20 weaned barrows of Danish Landrace breed. After a 5-day adaptation period cultures of the fungus Fusarium moniliforme were mixed into the animals' feed in concentrations that resulted in a daily intake of fumonisin B1 of 0, 10, 20 and 40 mg/kg feed. Feeding with the toxin was observed to exert no significant effect on body weight gain or feed consumption in the animals, no clinical signs were observed and no mortality traceable to toxic effects occurred. In computer tomography examinations performed in the second and fourth weeks mild and more severe pulmonary oedema was diagnosed in the experimental animals. The processes developing in the pulmonary parenchyma were corroborated by the mathematical and statistical evaluation procedures applied. The haematological parameters examined revealed no change attributable to toxic effects, while with respect to the biochemical parameters, an increase in aspartate aminotransferase (AST) activity dependent on dosage, indicating a pathological change in the liver, was ascertained in all three experimental groups. The free sphinganine to sphingosine ratio (SA/SO), which is regarded as the most sensitive bioindicator of fumonisin toxicosis, showed an increase proportionate to toxin concentration for all three dosages. Dissection revealed mild cases of pulmonary oedema in three of the animals given doses of 10 p.p.m. (n = 4), two mild and two severe cases in those exposed to 20 p.p.m. (n = 5), and severe cases in all five animals given 40 p.p.m. The oedema of non-inflammatory origin was confirmed by histopathological examinations. The findings of this experiment which indicate that in this study FB1 administered in substantially lower concentrations than those reported in the literature resulted in severe pathological changes, point to the importance of studies involving even lower doses.

Animal Feed↗
PubMed2000

A rule-based phonocardiographic method for long-term fetal heart rate monitoring.

A real-time method for fetal heart rate (FHR) monitoring based on signal processing of the fetal heart sounds is presented. The acoustic method, which utilizes an adaptive time pattern analysis to select and analyze those heartbeats that can be recorded without artefact, is guided by a number of rules involving an introduced confidence factor on the timing prediction. The algorithm was implemented in a low-power portable electronic instrument to enable long-term fetal surveillance. A large number of clinical tests have shown the very good performance of the phonocardiographic method in comparison with FHR curves simultaneously recorded with ultrasound cardiotocography. Indeed, approximately 90% of the time, the acoustic FHR curve remained inside a +/- 3 beats/min tolerance limit of the reference ultrasound method. The confidence was typically CF > 0.85. The acoustic method exceeded a +/- 5 beats/min limit relative to the ultrasound method approximately 5% of the time. Finally, no relevant FHR data was measured approximately 5% of the time.

Algorithms↗
PubMed2000

Cost-effectiveness of home telemedical cardiotocography compared with traditional outpatient monitoring.

We compared the cost of passive sensor telemedical non-stress cardiotocography performed at home and the same test performed by traditional equipment in an outpatient clinic in the Budapest area. The costs were calculated using two years' registered budget data from the home monitoring service in Budapest and the outpatient clinic of the department of obstetrics and gynaecology at the Haynal Imre University of Health Sciences. The traditional test at the university outpatient clinic cost 3652 forint for the health-care and 1000 forint in additional expenses for the patient (travel and time off work). This means that the total cost for each test in the clinic was 4652 forint. The cost of home telemedical cardiotocography was 1500 forint per test, but each test took 2.1 times as long. For a more realistic comparison between the two methods, we adjusted the cost to take account of the extra length of time that home monitoring required. The adjusted cost for home care was 3150 forint, some 32% lower than in the clinic. Passive sensor telemedical non-stress cardiotocography at home was therefore less expensive than the same test performed in the traditional way in an outpatient clinic.

Ambulatory Care↗
PubMed1999

Ten years' clinical experience with telemedicine in prenatal care in Hungary.

A multicentre randomized clinical trial of prenatal home care of pregnant women was carried out in Hungary. Pregnant women registered contraction activity of the uterus daily using a portable contraction monitor. The data were transmitted directly to the physician's PC for analysis. Of 748 women who entered the study, only 263 fulfilled all the requirements of randomization, monitoring and treatment. The preterm birth rate in the study group was half that of the control group. Telemedical prenatal monitoring improves perinatal results by providing more intensive and better observation of pregnant women.

Cardiotocography↗
PubMed1997

An improvement of the acoustic fetal heart rate monitoring using statistical evaluation of the abdominal signal.

An improved acoustical method for fetal heart rate (FHR) measurement is presented. The beat identification is based on the selection of the power peaks measured on two frequency channels. The identification of the valid peaks will be accomplished by rules, considering the timing and the amplitudes of the detected peaks with preferred search for pairs of the first and second sound. The introduced certainty factor as a function of the statistical probabilities that are related to the expected peaks, provides the reliability of the determined repetition time. Under a given certainty the result will be ignored and the FHR curve will be extended or left blank. The simplifications in the algorithms of the process reduce the required power consumption that enables its implementation in a low-power microcircuit and in this way to produce a battery-operated portable CTG instrument for long-term FHR monitoring on a passive.

Cardiotocography↗
PubMed1995

Detection of ochratoxin a in human blood and colostrum.

Ochratoxin A (OA) is one of the most frequent sources of mycotoxin contamination of feed plants in Hungary. It is produced by 10% of Aspergillus and 12% of Penicillium species, i.e. by the widely occurring "commonest" mould species. Human exposure to mycotoxins closely resembles that of swine. Fifty-two out of 100 human blood samples collected at random (52%) were found to contain ochratoxin A (0.2-12.9 ng/ml). Recent studies have clearly shown that OA has mutagenic, teratogenic and carcinogenic effects. Sensitivity to mycotoxins is known to be inversely related to age. Therefore, it was considered important to test human colostrum samples for OA content. Thirty-eight out of 92 colostrum samples (41.3%) collected from women in the first 24 hours post partum contained ochratoxin A (0.2-7.3 ng/ml). The HPLC method applied in this study is described in detail.

Aspergillus↗
PubMed1994

Effects of T-2 toxin treatment on the egg yield and hatchability in geese.

Ten groups of one-year-old geese, each including 10 layers and 3 ganders, were treated with T-2 toxin at doses of 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1.0 and 3.0 mg/kg body weight/day for 18 days by injection into the stomach. At the toxin dose of 0.1 mg/kg/day, the egg yield remained unchanged while the hatching rate slightly decreased. T-2 toxin administered at a dose of 0.2 mg/kg/day decreased the hatching rate and the egg yield. The toxin dose of 0.3 mg/kg/day resulted in a 50% reduction of the hatching rate. The mortality rate was significant at toxin levels higher than 0.8 mg/bwkg/day; however, 30% of the birds survived even the 3.0 mg/kg/day toxin dose.

Animals↗
PubMed1994

Perinatal oestrogen syndrome in swine.

Perinatal oestrogen syndrome (F-2 fusariotoxicosis occurring at the perinatal age) was studied in large pig herds and in animal experiments. The disease markedly lowered the conception rate of sows and gilts, and increased the number of repeat breeders. Litter size decreased and the number of stillbirths rose. Both the newborn piglets and the stillborn fetuses showed swelling of the vulva and teats and oedematous infiltration of the perineal region, ventral part of the abdomen and umbilicus, often accompanied by exudative-crusted inflammation, then necrosis of the teats. The number of piglets with splayleg and trembling increased. Gross and histopathological examination revealed enlargement of the ovary and uterus, with signs of follicle maturation in the ovary, glandular proliferation in the endometrium and epithelial proliferation in the vagina in addition to oedema and hyperaemia. In newborn piglets, the signs of hyperoestrogenism could be induced also experimentally, by feeding an F-2 toxin containing diet to pregnant sows. Intrauterine toxin effect was found to be primarily responsible for inducing the syndrome in newborn piglets. Because of its lower quantity, F-2 toxin excreted in the sow's milk is assumed to have a secondary role.

Animals↗
PubMed1994

Pathomorphological changes caused by T-2 trichothecene fusariotoxin in geese.

T-2 trichothecene fusariotoxin was administered to 110 laying geese and 33 ganders in the active egg production period through a tube at 2-day intervals on a total of 10 occasions. After the treatment, the geese were subjected to detailed pathomorphological examination. In the ovaries of layers, a cessation of follicle maturation and follicle degeneration dependent on the toxin dose were observed, accompanied by ovulation and consequent peritonitis in the birds that died and in some of those killed by bleeding. Additional findings included involution of the oviduct, lymphocyte depletion, necrosis and amyloidosis in the spleen, catarrhal enteritis, signs of colloid stasis in the thyroid and large numbers of secretory granules in the cytoplasm of the adrenaline-producing cells of the adrenal gland. In the ganders, toxin administration did not reduce the intensity of spermatogenesis but in the spleen, intestine and endocrine glands it caused changes similar to those seen in the layers.

Animals↗
PubMed1993

Glycoprotein gp50-negative pseudorabies virus: a novel approach toward a nonspreading live herpesvirus vaccine.

Essential herpesvirus glycoproteins are involved in membrane fusion processes during infection, e.g., viral penetration and direct cell-to-cell transmission. We previously showed that the gD-homologous glycoprotein gp50 of pseudorabies virus (PrV) is essential for virus entry into target cells but proved to be dispensable for direct viral cell-to-cell spread in cell culture (I. Rauh and T. C. Mettenleiter, J. Virol. 65:5348-5456, 1991). For gp50-negative (gp50-) viruses, after phenotypic complementation necessary for primary infection, the only means of viral spread is by way of direct cell-to-cell transmission. In contrast, virus mutants lacking the essential gB-homologous glycoprotein gII after phenotypic complementation are only able to infect primary target cells and are blocked in further viral spread. To analyze how these in vitro phenotypes translate into virus replication in the animal, mice were infected intranasally with gp50- or gII- PrV mutants after prior phenotypic complementation by propagation on cell lines providing the essential glycoprotein in trans. Our results show that whereas the gII- mutants did not cause disease or any symptoms, gp50- mutants derived from two different PrV strains were fully virulent, with animals exhibiting severe symptoms ultimately leading to death. However, free infectious virus could not be recovered from either gp50- or gII- PrV-infected animals. We conclude that direct cell-to-cell transmission as the only means of viral spread of the gp50- mutants is sufficient for a full virulent phenotype in mice. After infection of pigs with phenotypically complemented gp50- PrV, only mild symptoms were observed, whereas the gII- mutant was totally avirulent. In both cases, shedding of infectious virus did not occur, in contrast to results with animals infected by gX- PrV that showed severe signs of disease and extensive virus shedding. After challenge infection with the highly virulent NIA-3 strain, the previously gII- PrV-infected animals exhibited severe symptoms, whereas the gp50- PrV-infected pigs showed a significant level of protection. In conclusion, vaccination with a PrV mutant lacking glycoprotein gp50, which is unable to spread between animals because of a lack of formation of free infectious virions, can confer on pigs protection against challenge infection. These results provide the basis for the development of new, nonspreading live herpesvirus vaccines based on gp50- PrV mutants.

Animals↗