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Biomedical subjects

G Kovács

Publications and source records attributed to G Kovács.

At least 19 recordsLinked to original sources
PubMed2006

Multimodal therapy of anal cancer added by new endosonographic-guided brachytherapy.

BACKGROUND: The most appropriate therapy for anal cancer is external beam radiotherapy (EBRT) combined with chemotherapy (CTX). The significance of additional brachytherapy is still under evaluation. We report on our experience of combined modality therapy of anal cancer and transrectal ultrasound (TRUS)-guided high-dose rate (HDR) afterloading therapy, referring to results of a study published in 1998 by the coauthors. METHODS: From 1993 to 2001, 50 patients with anal cancer were treated. After combined RCTX, HDR 2 x 4 Gy brachytherapy was administered based on TRUS imaging as a target. RESULTS: In five patients (10%), tumor recurrence occurred or the tumor did not respond to therapy, and four (8%) developed distant lymph nodes or organ metastases. Five patients (10%) had to undergo salvage abdominoperineal resection because of suspected recurrence. Specific disease-related 5-year survival was 82%. Therapy-associated complications in terms of sphincter necrosis and incontinence were observed in three patients (6%). CONCLUSIONS: TRUS-guided brachytherapy permits excellent local tumor control and results in minimal treatment-related morbidity. Consequently, TRUS-guided brachytherapy may be a useful addition to current combined modality treatment regimens for anal cancer.

Aged↗
PubMed2006

Bacteria isolated from the different developmental stages and larval organs of the obligate parasitic fly, Wohlfahrtia magnifica (Diptera: Sarcophagidae).

Wohlfahrtia magnifica (Diptera: Sarcophagidae) is the major myiasis-causing fly species in the whole of Eurasia for most important domestic animals. The aim of the present work was to obtain data on the culturable bacteria isolated under aerobic conditions from this fly: bacteria were isolated from all developmental stages (larvae, pupa, and imago) of Wohlfahrtia magnifica, and the third-stage larval organs were also sampled. To determine the possible antagonistic effects between the dominant bacterial groups, an antibiosis assay was carried out. Plating and isolation of bacteria was performed by classical microbiological methods. Characterization of the isolated strains was carried out via a polyphasic approach; classical phenotypic tests, chemotaxonomical examinations, and 16S rDNA sequence analyses were also applied. In the case of maggot macerate samples, members of the family Enterobacteriaceae were characteristic. Members of a new genus (Schineria) belonging to the gamma subdivision of proteobacteria were also isolated. According to our data, the shifts in the Schineria and Proteus populations within the larvae are strongly influenced by their interactions with each other and among the members of the family Enterobacteriaceae. The pupa and imago samples contained several other Gram-negative bacteria (Stenotrophomonas, Brevundimonas, etc.). Among Gram-positive bacteria, in all maggot macerate samples, members of the genus Bacillus and the Arthrobacter-Micrococcus group of actinobacteria were dominant (neither of them was a producer or sensitive to the compounds of other microorganisms), and bacteria related to the genus Corynebacterium were also found. From the larvae Aureobacterium liquefaciens and Enterococcus faecalis were isolated, and from the pupae Dietzia maris and Enterococcus faecalis. In the samples of third-stage larval organs, the dominant groups were the same as in the third-stage larval macerate sample; however, several additional genera/species were observed (Rhodococcus fascians, Streptomyces sp., Rathayibacter sp., Bacillus thuringiensis/cereus).

Animal Structures↗
PubMed2006

[Emergent treatment of a malignant peripheral epineurial tumour].

BACKGROUND: Malignant peripheral epineurial tumours are a group of tumours that derive histomorphologically from peripheral nerve sheaths. They occur sporadically, with an incidence of approximately 0.001%, and very rarely require emergency operation. PATIENT AND PROCEDURE: An athletic 19-year-old man presented to an orthopaedic outpatient clinic with lumboischialgia and weakness of the third and fourth left toes. A 12 x 10 x 8-cm paravertebral/retroperitoneal tumour was diagnosed by CT, and the patient was referred to our clinic. For classification, CT-assisted puncture of the tumour was carried out. A haemorrhage into the tumour resulted from the puncture, with consequently lower Hb level and progressive peripheral sensomotoric deficits demanding emergency surgery on a weekend. On this occasion, the tumour was resected together with the L5 and S1 nerve roots through cooperation between the general surgical and neurosurgical departments and was classified as a malignant peripheral epineurial tumour in the rapid stage. Due to the spinal R2 resection, after-loading probes were inserted and the tumour bed was clip-marked. Percutaneous radiotherapy and brachytherapy followed postoperatively. Shortly afterwards, relaparotomy had to be performed due to an adhesive ileus, from which the patient recovered quickly. Chemotherapy was carried out due to a G2 tumour classification. The patient is currently undergoing rehabilitation, during which the peripheral neurological deficits are improving gradually. CONCLUSION: This rare case of a malignant peripheral epineurial tumour with acute symptoms demonstrates the ability of hospitals with maximum care facilities to maintain services even in times of financial cuts in health care services.

Adult↗
PubMed2006

Early European experience with the MammoSite radiation therapy system for partial breast brachytherapy following breast conservation operation in low-risk breast cancer.

Preliminary results of ultrasound studies do exist in the literature on the successful use of the MammoSite Radiation Therapy System (RTS), a new device for delivering brachytherapy following breast-conserving surgery. In Europe, some groups started a prospective multicentre trial to investigate the use of the MammoSite RTS. In this early publication, we analysed the surgical procedure and placement of the MammoSite, treatment planning and radiation delivery complications, and early cosmesis, as well as the comfort of the patients. Between June 2002 and March 2005, a total of 54 low-risk breast cancer patients fulfilling the enrolment criteria were implanted intra- or postoperatively using the MammoSite applicator. After inflating the balloon in the excision cavity, the reference isodose was defined 1cm from the balloon's surface. Twenty-eight patients were treated with primary brachytherapy with a total dose of 34 Gy (2x3.4 Gy) and 16 patients had a boost with a mean dose of 13.3 Gy (range: 7.5-15 Gy; 2x2.5 Gy) combined with external beam radiotherapy (EBRT). Doses ranged between 46 and 50 Gy. We analysed the postimplant anatomic position of the applicator in relation to the skin and chest wall as well as the geometric form of the balloon via ultrasound, computed tomography and X-ray before, during and after the treatment. Forty-four out of 54 patients (81.5%) were eligible for MammoSite RTS brachytherapy. Ten patients were excluded from the trial due to the strict study criteria and received no brachytherapy. Balloon rupture occurred in two cases. We observed seroma in 16 patients (36%); furthermore, an abscess developed in two patients (4.5%) within 3 months of implantation. Postoperative air gaps and haematoma were successfully reduced by draining the operation cavity in one institution. At a mean follow-up of 14 months (range 3-31 months), the skin-related side effects observed were skin discoloration or inflammation in 36 patients (82%) and teleangiectasia in eight patients (18%). The MammoSite RTS is a feasible treatment modality for postoperative partial breast irradiation after breast-conserving surgery for selected low-risk breast cancer patients. The main advantage of the system is the necessity of only one applicator for the delivery of fractionated radiotherapy over a 5-day treatment period. In addition, patient tolerance of the procedure is high. Based on this early experience, the method may serve as a successful alternative to conventional multicatheter brachytherapy for a highly select group of patients, but we have to bear in mind the higher level of acute toxicity.

Adult↗
PubMed2006

Rickettsiae of the spotted-fever group in ixodid ticks from Hungary: identification of a new genotype ('Candidatus Rickettsia kotlanii').

Three common European 'anthrophilic' ticks, Ixodes ricinus, Haemaphysalis concinna and Dermacentor reticulatus, were collected in Hungary and tested, in assays based on nested PCR, for rickettsiae of the spotted-fever group. Low percentages of I. ricinus (2.7%) and H. concinna (1.0%) and a high percentage of D. reticulatus (26.8%) were found to be infected. The rickettsiae in the ticks were then identified, by sequencing of the genes coding for 16S ribosomal RNA (16S rDNA), citrate synthase (gltA) and the rOmpA outer-membrane protein (ompA), as Rickettsia helvetica, Rickettsia monacensis, Rickettsia sp. RpA4, or what is probably a newly recognized Rickettsia species ('Candidatus Rickettsia kotlanii'). These results raise the possibility that rickettsiae other than Rickettsia slovaca are involved in human disease in Hungary. Current knowledge on the distributions of the rickettsiae of the spotted-fever group that are emerging in Europe is also summarized.

Animals↗
PubMed2005

Diversity of alkaliphilic and alkalitolerant bacteria cultivated from decomposing reed rhizomes in a Hungarian soda lake.

Bacterial communities associated with decomposing rhizomes of Phragmites australis were investigated in Lake Ferto (Neusiedlersee, Hungary). Alkaliphilic and alkalitolerant strains were isolated on cellulose-containing alkaline medium spread with dilutions of scrapings taken from the surface of the decaying plant material. Fifty-one strains were grouped by numerical analysis based on physiological tests and BIOLOG sole carbon source utilization data. The strains identified by 16S rDNA sequence comparisons included members of low G+C Gram positives (Marinibacillus marinus, Bacillus cereus, and Exiguobacterium aurantiacum), high G+C Gram positives (Nesterenkonia halobia and Dietzia natronolimnea), alpha-proteobacteria (Pannonibacter phragmitetus), and gamma-proteobacteria (Pseudomonas pseudoalcaligenes and Halomonas venusta). Most of the strains were characterized by aerobic chemoorganotrophic respiratory metabolism and utilized several different carbon sources, although no direct cellulolytic activity was observed. Results of the pH and salt tolerance tests revealed optimuma in most cases at pH 11 and at the presence of 2.5-5% NaCl. These bacteria probably occupy niches in the aerobic, alkaline, water-influenced environments on the decomposing reed surfaces.

Bacteria, Aerobic↗
PubMed2004

The role of TTF-1 in differentiating primary and metastatic lung adenocarcinomas.

Thyroid transcription factor-1 (TTF-1) is a sensitive marker for pulmonary and thyroid adenocarcinomas. The aim of this work was to determine its usefulness in distinction between primary and metastatic lung adenocarcinomas. We have examined the expression of TTF-1 in 100 solitary pulmonary nodules. They included 50 stage I peripheral primary bronchial adenocarcinomas (30 men, 20 women, mean age: 60 years) and 50 metastatic pulmonary adenocarcinomas (21 men, 29 women, mean age: 57 years) of different origins, such as breast (13), colon (13), rectum (13), kidney (7), stomach (2), and thyroid gland (2). TTF-1 immunohistochemistry was performed on formalin-fixed, paraffin-embedded tissues. In primary bronchial adenocarcinomas we found immunopositivity in 46/50 cases, among them 30 cases showed strong nuclear immunostaining. In four primary adenocarcinoma cases the observed immunopositivity was localized to the cytoplasm. Out of the metastatic adenocarcinomas all but the 2 thyroid cancers were negative. Both thyroid tumors showed strong immunopositivity. Our results confirm that TTF-1 immunohistochemistry is a very sensitive and highly specific method in the differential diagnosis of primary and metastatic lung adenocarcinomas and should be used in the everyday clinical practice.

Adenocarcinoma↗
PubMed2004

Biological UV dosimeters in simulated space conditions.

Polycrystalline uracil thin layers participate in the phage and uracil response (PUR) experiment, assigned to the biological dosimetry of the extraterrestrial solar radiation on the International Space Station (ISS). In ground based experiments (experiment verification tests), the following space parameters were simulated and studied: temperature, vacuum and short wavelength UV (UV-C, down to 200 nm) radiation. The closed uracil samples proved to be vacuum-tight for 7 days. In the tested temperature range (from -20 to +40 degrees C) the uracil samples are stable. The kinetic of dimer formation (dimerization) and reversion (monomerization) of uracil dimers due to short wavelength UV radiation was detected, the monomerization efficiency of the polychromatic deuterium lamp is higher than that of the germicidal lamp. A mathematical model describing the kinetic of monomerization-dimerization was constructed. Under the influence of UV radiation the dimerization-monomerization reactions occur simultaneously, thus the additivity law of the effect of the various wavelengths is not applicable.

Dimerization↗
PubMed2004

Simulation experiments of the effect of space environment on bacteriophage and DNA thin films.

The main goal of PUR experiment (phage and uracil response) is to examine and quantify the effect of specific space conditions on nucleic acid models. To achieve this an improved method was elaborated for the preparation of DNA and bacteriophage thin films. The homogeneity of the films was controlled by UV spectroscopy and microscopy. To provide experimental evidence for the hypothesis that interplanetary transfer of the genetic material is possible, phage T7 and isolated T7 DNA thin films have been exposed to selected space conditions: intense UVC radiation (lambda=254 nm) and high vacuum (10(-4) Pa). The effects of DNA hydration, conformation and packing on UV radiation damage were examined. Characteristic changes in the absorption spectrum, in the electrophoretic pattern of DNA and the decrease of the amount of PCR products have been detected indicating the photodamage of isolated and intraphage DNA.

Bacteriophage T7↗
PubMed2003

Development of a non-lethal selection system by using the aadA marker gene for efficient recovery of transgenic rice (Oryza sativa L.).

The application of aminoglycoside-3"-adenyltransferase ( aadA) gene-mediated streptomycin resistance for non-lethal selection of transgenic rice resulted in plant regeneration frequencies under selection pressure as high as those in non-transformed controls without selection. Since streptomycin does not kill non-transgenic cells, and allows plant regeneration from them, a selection procedure was developed that made the visual identification of transgenic calli and regenerants possible. For callus-level selection, a vital pH indicator-Chlorophenol Red-was applied together with streptomycin, making use of the phenomenon that fast-growing cell lines lower the pH in the culture medium. Transgenic plants were selected according to their main distinctive features; their green colour (photomixotrophic assimilation), and more intense growth. At the same time, non-transgenic regenerants were bleached (heterotrophic assimilation), and growth was retarded in the presence of streptomycin and sucrose. The final efficiency of genetic transformation based on streptomycin resistance was found to be double that of transformations where the selective agent was l-phosphinothricin, and nearly three times more compared to transformations resulting in hygromycin-resistant regenerants. To the best of our knowledge, this is the first report on producing nuclear transformed rice plants by using a non-lethal selection strategy based on the chimaeric aadA gene.

Aminobutyrates↗
PubMed2003

Metastatic tumors of the orbit: a retrospective study.

PURPOSE: To present the clinical features and facts on prognosis, therapy and diagnostics of orbital metastases treated in the Orbital Center Kiel. METHODS: We reviewed the records of 20 patients with orbital metastases (ca. 2% of all orbital patients seen in a 10-year period). RESULTS: The mean age at first manifestation of orbital symptoms was 64 years. On average, 64 months was the period of time between the onset of the primary disease and orbital manifestation. The sites of the primary tumors were breast (8), choroid (2), prostate (2), gastrointestinal tract (3), lung (2), urinary bladder (1), Schmincke tumor of the throat (1) and unknown origin (1). Eleven patients were female, 9 male. The main primary symptoms consisted of lid swelling (11), red eye (9), diplopia (10), and proptosis (7). Although the majority (16/20) were treated by chemotherapy, radiotherapy or surgery, 19 patients died after a mean survival time of 14.7 months. CONCLUSION: Orbital metastases remain an unfavorable prognostic factor, but the diagnosis and treatment are still important in order to prevent loss of vision and improve the patient's quality of life. As previous studies have shown, the overall survival rate is still as limited as nearly half a century ago.

Adult↗
PubMed2003

Effects of surface cues on macaque inferior temporal cortical responses.

Humans are able to recognize objects when surface details, such as colour, texture and luminance gradients, are not available. By systematically eliminating colour, texture, shading, contrast and inner contours from given objects, we tested whether certain shape-selective inferior temporal cortex (IT) neurons of awake rhesus monkeys remain selective for these objects as the surface information is reduced. In psychophysical experiments, we established that the rhesus monkey can identify the shape of a coloured object largely independently of its surface characteristics and, to a lesser degree, of its inner contours. Shape selectivity of the neurons does not change when texture and shading are concealed. The responsiveness of the neurons is also affected by the removal of these surface attributes. The IT neurons were found to respond highly similarly to objects brighter or darker than their background. Selectivity for shape is preserved when the contrast is reversed. Deletion of the inner contours, outlining the main parts of the objects, did not affect the responses and selectivity of the IT neurons. These findings indicate that the IT can contribute to the invariant perception of objects having different surface details.

Animals↗
PubMed2002

Effects of glucagon and insulin on plasma glucose, triglyceride, and triglyceride-rich lipoprotein concentrations in laying hens fed diets containing different types of fats.

The influence of dietary fat supplementations differing in the ratio of n-6 to n-3 polyunsaturated fatty acids (PUFA) on the effects of glucagon and insulin on plasma glucose, triglyceride (TG), and TG-rich lipoprotein concentrations was investigated in laying hens. Birds were fed either a low-fat control diet (LF) or diets supplemented with 4% pumpkin seed oil (PO; rich in n-6 PUFA) or 4% cod liver oil (CO; rich in n-3 PUFA). After 4 wk feeding of the experimental diets, hens were implanted with wing vein catheters and injected with porcine glucagon (20 microg/kg BW) and porcine insulin (0.5 IU/kg BW), 2 to 5 h after oviposition. Plasma glucose, TG, and TG-rich lipoprotein concentrations were determined from 10 min pre-injection to 60 min post-injection. PO diet resulted in a prolonged plasma glucose response to glucagon administration and altered hypoglycemic response to insulin. However, CO diet did not influence plasma glucose response to either glucagon or insulin administration compared to LF diet. The effects of glucagon and insulin on plasma TG and TG-rich lipoproteins were similar for all diets regardless of the amount or type of fat. The results suggest that feeding dietary fats with high n-6 to n-3 PUFA ratio alters the glucagon and insulin sensitivity of plasma glucose in laying hens. Fats rich in n-3 PUFA seem to have no influence on the plasma glucose response to glucagon and insulin.

Animals↗
PubMed2002

A combined electrophysiological and behavioural study for the assessment of activity-dependent changes in mice.

Activity-dependent adaptive changes in the nervous system involve structural and functional changes in the cortical circuitry. In this work the cortical function was studied by repeated recording of the somatosensory and motor potentials evoked by whisker deflections after altered sensory-motor experience in adult mice. The latencies of motor and somatosensory evoked potentials were found to shorten, while their amplitudes decreased, after a behavioural challenge involving the vibrissal apparatus. Sensory deprivation achieved by whisker trimming resulted in a partial reversal of the changes observed after increased activity. The derived parameters imply that cortical information processing speeds up as a result of experience, while decreased activity has the opposite effect. The methods used throughout the experiment were minimally invasive, and thus proved to be sufficient for the long-term follow-up of cortical functions.

Animals↗
PubMed2002

Investigations on rhizoplane Actinobacteria communities of papyrus (Cyperus papyrus) from an Egyptian wetland.

Wetlands have important global ecological functions, which include carbon storage and water interception. Wetland contributes to the maintenance of regional and global biodiversity. Though many important wetland ecological functions are based on microbial metabolism, we have scanty knowledge on microbial diversity in wetlands. Plant rhizoplane habitats are considered to harbor highly diverse bacterial communities. Most of the floating mats on river Nile are dominated by papyrus (Cyperus papyrus). Papyrus root samples were collected from a floating mat at the "Gold Island" inside the Nile River at Cairo, Egypt in February 1996 and May 1997 in order to investigate the rhizoplane actinobacteria communities. The root-tip regions were cut off, repeatedly washed, macerated and plated. Using the plate-count technique with three actinobacteria media, an average of 2.1 x 10(4) CFUg-1 root actinobacteria were obtained. All actinobacteria colonies were isolated, purified and investigated by classical and molecular methods. In the papyrus rhizoplane Streptomyces anulatus, Micromonospora sp., Rhodococcus luteus, Verrucosispora gifhornensis and Aureobacterium liquefaciens dominated, moreover Actinoplanes utahensis, and Str. diastaticus were also present. The physiological traits of the members of dominant groups revealed that these bacteria might be active in the rhizoplane and can be present there is their vegetative forms.

Actinobacteria↗
PubMed2001

[High dosage brachytherapy and external irradiation of localized prostate carcinoma--results at the Kiel University Clinic].

To evaluate a new therapy protocol for local dose escalation by high dose rate (HDR) brachytherapy for survival, morbidity and prognostic variables in men with localized prostate cancer. The prospectively recorded files of 189 men aged in median 69 years with a mean follow-up of 6 years (12-143 months) receiving curatively intended combined high dose rate (HDR) 192-iridium-brachytherapy (BT) and external beam radiation (EBR) for locally confined prostate cancer were analyzed. Mean age was 68.2 (range 44-84 years). Hundred and twenty-seven patients had T1-2 tumors, and 62 patients had T3-tumors. The total planned dose applied by external beam radiation was 50 Gy in the pelvis, and 40 Gy in the prostate by in-field-dose modification. The HDR-brachytherapy was delivered in two fractions. The dose per fraction amounted 15 Gy. Mean survival was 6 years (range 12-143 months), 76.7% of the patients survived and 86.3% were disease-free. The biochemical non-evidence of disease rate (BNED) was 78%. Univariate survival analysis revealed that low stage (T1-2), low grade (G1-2), normal PSA status after radiation therapy, and no adjuvant hormonal treatment were associated with long survival. However, the stratification for adjuvant hormonal treatment was not according to random. In multivariate analyses PSA status was an independent prognostic factor. The six year results confirm that local dose escalation by HDR-brachytherapy and external beam radiation is curative in men with locally confined prostate cancer. The results are especially in high risk patients encouraging.

Aged↗