Biomedical subjects

G Kiss

Publications and source records attributed to G Kiss.

At least 19 recordsLinked to original sources

PubMed2001

[Diabetes mellitus as a general membrane disease and its consequences].

The metabolic disturbances and their consequences in diabetes mellitus are well known more or less in details too. However, our knowledge on the diabetic disorders in membrane functions are limited. These damages are connected mostly with the disregulation of the membrane protein syntheses due to deficiency of insulin. In this review the impairments of the Na(+)-pump and the Ca(2+)-transport mechanisms as well as the insulin-dependent glucose transporter GLUT4 will be discussed in diabetes. The capacity of these transporters could be decreased even more than 50 percent in diabetes. This is the reason why using the same dose of cardioactive steroids as if in not diabetic subjects--can cause toxic alterations on the heart in diabetic patients. Insulin regulates not only the expression of some membrane proteins but it can initiate the translocation of the Na(+)-pump and GLUT4 from the intracellular membrane compartments to the plasma membrane in muscle, heart and adipose tissue. Therefore the uptake of K+ and glucose into these tissues will increase significantly under the acute influence of insulin. Untreated diabetic patients generally show hyperkalemia. Forceful treatment with insulin of these subjects often causes severe hypokalemia as a consequence of sudden translocation of the Na(+)-pump. Different Ca(2+)-transport systems are also impaired in diabetes. These changes may result significantly higher free Ca2+ concentration in the cytoplasma of cardiomyocytes. This is one of the most important reason for the Ca2+ overloading and ultimately for heart death. According to authors opinion, beside the dangerous metabolic disorders, general membrane damage and extended disturbances in membrane functions are also very characteristic for diabetes. The acknowledgement of these alterations are very important for the exact planning of the up to date treatment of diabetes.

Adipose Tissue↗

PubMed2001

Streptozotocin-induced diabetes alters the oligomerization pattern of acetylcholinesterase in rat skeletal muscle.

AIMS/HYPOTHESIS: Diabetes mellitus has a serious effect on most of the properties of skeletal muscles. Changes in neuromuscular transmission are also involved in propagating the disease. METHODS: In our experiments, acetylcholinesterase was extracted from the fast extensor digitorum longus and slow soleus muscles of control, non-treated 6-week-diabetic and insulin-treated diabetic rats. The extracts were applied to velocity sedimentation and acetylcholinesterase activity was determined. RESULTS: We observed considerable differences in the distribution of individual acetylcholinesterase molecular forms in diabetic fast muscles. This included a 59% decline in G4 content together with a fivefold increase in A8 and a 53 % increase in A12 activity resulting in a shift of acetylcholinesterase profile characteristically towards slow muscles. These alterations were partly reversed by insulin treatment. CONCLUSION/INTERPRETATION: In slow muscles diabetes caused an increase in G4 activity without affecting the sedimentation profile. Decline in G4 content in fast muscles could contribute to enhanced desensitization of acetylcholine receptors in diabetes.

Acetylcholinesterase↗

PubMed2001

The seasonal changes in the concentration of polycyclic aromatic hydrocarbons in precipitation and aerosol near Lake Balaton, Hungary.

The concentration of polycyclic aromatic hydrocarbons (PAHs) in atmospheric precipitation and aerosol samples was monitored in a rural site by Lake Balaton, Hungary to examine the seasonal variation. The seasonal mean concentration of individual 3-6-ring PAHs in precipitation varied from 1 to 54 ng l-1 and from 3 to 350 ng l-1 in summer and winter, respectively. In the atmospheric aerosol samples the seasonal mean concentration of PAHs varied from 4 to 880 pg m-3, from 4 to 300 pg m-3, from 11 to 1050 pg m-3 and from 36 to 5000 pg m-3 in spring, summer, autumn and winter, respectively. Wet (412 micrograms m-2 year-1) and aerosol (190-300 micrograms m2 year-1) deposition rates were also estimated indicating that the two processes are of comparable importance in the removal of 3-6-ring PAHs from the atmosphere.

Aerosols↗

PubMed2001

Palladium-catalyzed Reppe carbonylation.

PdX2L2/L/HA (A = weakly coordinating anion, L = phosphine) complexes are active catalysts in the hydroesterification of alkenes, alkynes, and conjugated dienes. Shell, the only major corporate player in the field, recently developed two very active catalyst systems tailored to the hydroesterification of either alkenes or alkynes. The hydroesterification of propyne with their Pd(OAc)2/PN/HA (PN = (2-pyridyl)diphenylphosphine, HA = strong acid with weakly coordinating anion, like methanesulfonic acid) catalyst has been declared commercially ready. However, despite the significant progress in the activity of Pd-hydroesterification catalysts, further improvements are warranted. Thus, for example, activity maintenance still seems to be an issue. Homogeneous Pd catalysts are prone to a number of deactivation reactions. Activity and stability promoters are often corrosive and add to the complexity of the system, making it less attractive. Nonetheless, the versatility of the process and its tolerance toward the functional groups of substrates should appeal especially to the makers of specialty products. Although hydroesterification yields esters from alkenes, alkynes, and dienes in fewer steps than hydroformylation does, the latter has some advantages at the current state of the art. (1) Hydroformylation catalysts, particularly some recently published phosphine-modified Rh systems, can achieve very high regioselectivity for the linear product that hydroesterification catalysts cannot match yet. By analogy with hydroformylation, bulkier ligands ought to be tested in hydroesterification to increase normal-ester selectivity. (2) Hydroformylation is proven, commercial. Hydroesterification can only replace it if it can provide significant economic incentives. Similar or just marginally better performance could not justify the cost of development of a new technology. (3) Hydroesterification requires pure CO while hydroformylation uses syngas, a mixture of CO and H2. The latter is typically more available and less expensive (for industrial applications CO is most often separated from syngas). (4) The acid component of the hydroesterification catalyst makes the process corrosive. It would be desirable to develop new hydroesterification catalysts that do not require acid stabilizer/activity booster. Clearly, any new hydroesterification technology will directly compete with the hydroformylation route. This is especially true for olefin feeds, since both processes add one CO to the olefin, yielding oxygenates that can be converted into identical products. For some niche applications, like the production of MMA from propyne, hydroesterification seems to have an advantage as compared to hydroformylation due to the high activity and selectivity of the Pd(OAc)2/(2-pyridyl)diphenylphosphine catalyst. Since hydroesterification is an emerging technology, it is reasonable to assume that the potential for improvement is greater than in the mature hydroformylation. It is therefore possible that hydroesterification will become competitive in the future; thus, continued effort in the field is warranted.

Alkenes↗

PubMed2000

On-line size-exclusion chromatography/electrospray ionisation mass spectrometry of aquatic humic and fulvic acids

Isolated aquatic humic and fulvic acids were analysed with on-line size exclusion chromatography/electrospray ionisation mass spectrometry (SEC/ESI-MS). An eluent composition which enabled electrospray ionisation was identified. The SEC separation improved interpretability of mass spectra and may open up new possibilities for molecular weight determination of humic substances. A linear dose-response relationship over a factor of 20 was obtained and the limit of detection was 50ng/uL for humic and fulvic acids. Spectral changes due to different ionisation conditions (pH and cone voltage) were investigated. A natural water sample from a Swedish lake was analysed. Copyright 2000 John Wiley & Sons, Ltd.

Journal Article↗

PubMed1999

Electrokinetic injection in capillary electrophoresis and its application to the analysis of inorganic compounds.

In capillary electrophoresis, electrokinetic injection is a highly controversial sampling technique. It is a simple mode of sample introduction which is suitable for on-line preconcentration of the analytes, but its precision and accuracy are more strongly affected by experimental conditions compared to hydrodynamic injection. In the first part of this paper the features of electrokinetic and hydrodynamic injections are compared, followed by a detailed discussion on the different biases of electrokinetic injection and on how to reduce them. Finally, applications of the electrokinetic injection are reviewed with special emphasis on the analysis of inorganic compounds.

Anions↗

PubMed1998

Follow-up biological and genotoxicological monitoring of acrylonitrile- and dimethylformamide-exposed viscose rayon plant workers.

In order to investigate the genotoxic effects of occupational acrylonitrile (ACN) and dimethylformamide (DMF) exposures, clinical serum and urine parameters and genotoxicological endpoints such as chromosome aberration (CA), sister chromatid exchange (SCE), high frequency SCE (HFC), cell cycle kinetics, and UV-induced unscheduled DNA synthesis (UDS) were followed up three times during a 20-month period in peripheral blood lymphocytes (PBL) of 26 workers (13 maintainers and 13 fiber producers) occupationally exposed to ANC and/or DMF in a viscose rayon plant, 26 matched control subjects, and six industrial controls (all males). Six of the 26 exposed subjects were hospitalized because of liver dysfunction that had developed due to inhalative DMF exposure. The rate of smoking was estimated on the basis of serum thiocyanate (SCN) levels. Average peak air ACN and DMF concentrations were over the maximum concentration limits at the time of both investigations. Urine ACN and monomethyl-formamide (MMF) excretions of the exposed subjects were almost doubled after work shifts. An increase in lymphocyte count (in months 0 and 7), and severe alterations in the liver function were observed in the exposed subjects. In PBLs the proliferative rate index (PRI) was already increased in month 0 compared with the controls. In each study, significant increases in CA and SCE frequencies, as well as increases in UDS were found in PBLs of the exposed subjects. The frequencies of chromatid breaks and acentric fragments further increased in month 7 and remained constantly elevated in month 20. Increased yields of both chromatid and chromosome-type exchange aberrations first appeared in month 20, when HFCs were 2.72 times more frequent in fiber producers than in maintainers. The role of some important biological confounding factors (age, white blood cell count, and hematocrit) and lifestyle confounding factors (smoking and drinking habits) were subjected to an analysis of variance during the second study. Increased CA, SCE, and UDS were found both in control and exposed smokers when current smoking was established on the basis of the serum SCN levels. The cytogenetic data suggest that occupational exposures to ACN and DMF induce considerable genotoxic consequences and may increase the cancer risk in the exposed human populations.

Acrylonitrile↗

PubMed1998

Cortical evoked potentials of the vesicourethral junction--a predictor for the outcome of intravesical electrostimulation in patients with sensory and motor detrusor dysfunction.

The evaluation of cortical evoked potentials after stimulation of the vesicourethral junction shows accurate and reproducible results and offers an elegant technique for evaluation of the viscerosensory pathways in patients with lower urinary tract dysfunction. The results must be considered in context with the results of simultaneously investigated pudendal somatosensory evoked potentials and the clinical symptomatology. They are of great help (1) in differentiating between intraspinal and extraspinal lesions of the afferent pathways of the detrusor if the etiology is unknown, (2) in differentiating between neurogenic and myogenic damage to the urinary bladder, and (3) in selecting patients not suitable for intravesical electrotherapy for bladder rehabilitation.

Adolescent↗

PubMed1997

[Mandibular reconstruction using a microvascular method in the transplantation of a fibular flap].

The best results in mandibular reconstruction are achieved by transplantation of vascularised bone. This transplant has an own blood supply therefore its surviving is not influenced by the non-sterile environment of the oral cavity and the insufficient blood supply of the operated area (caused by scar or radiation). A new promising method for reconstruction of a wide segmented defect of the mandible is vascularised fibular flap transplantation. Eight consecutive patients treated with fibular flap transplantation in 1993 and 1994 were reviewed. Osteo- and osteo-cutan flaps were used for reconstruction of the composite tissue defects. The authors report on the surgical technique and their first experiences. The authors consider the application of the fibular flap the most successful procedure of all types of reconstruction of segmented mandibular defect.

Female↗

PubMed1997

New combination for the therapy of canine otitis externa. I. Microbiology of otitis externa.

In order to compound a new drug combination against canine otitis externa (OE), 515 dogs affected with OE were subjected to physical examination and microbiological analysis of their ear exudates. OE was erythematous-ceruminous in 83 per cent and suppurative in 17 per cent of the patient material. Erythematous-ceruminous inflammations were characterised by severe pruritus and accumulation of brownish, greasy cerumen in the auditory canal. The yeast Malassezia pachydermatis was isolated from the ears of 76 per cent of the dogs, often in combination with Staphylococcus intermedius bacteria. M pachydermatis showed the most sensitivity, in decreasing order of efficacy, to ketoconazole, econazole, clotrimazole, miconazole and nystatin. S intermedius isolates were most sensitive to amoxycillin-clavulanic acid, enrofloxacin, cephalexin and gentamicin. The microorganism most frequently isolated from dogs with suppurative OE was Pseudomonas aeruginosa; in some cases Proteus, Streptococcus and Pasteurella were also isolated. The P aeruginosa isolates showed the highest sensitivity to gentamicin, polymyxin B and tobramycin.

Aminoglycosides↗

PubMed1997

New combination for the therapy of canine otitis externa. II. Efficacy in vitro and in vivo.

A new, effective drug combination was developed for the therapy of canine otitis externa (OE) by taking into consideration the microorganisms most frequently isolated from dogs affected with OE, their combination, their drug sensitivity and the type and incidence of ear canal inflammation. The antimycotic active ingredient of the combination is ketoconazole, its antibacterial component is gentamicin sulphate, while its antiphlogistic constituent is mazipredone hydrochloride. Based upon the results of in vitro pharmacodynamic tests, the antifungal activity of the combination is superior to that of ketoconazole used alone at the same concentration. A total of 210 dogs affected with OE were treated with the combination: 94.2 per cent of them became clinically symptomless and microbiologically negative in an average of 8.5 days. No adverse reactions were observed in connection with the use of the drug combination. The therapeutic results can be attributed to the high antifungal efficacy of the combination demonstrated in vitro and to the favourable properties of the solvent mixture.

Animals↗

PubMed1997

[Fee flap from the fibula: microsurgical method for the substitution of mandibular loss].

The authors report on the microsurgery method of the vascularized free fibula flap transplantation for the reconstruction of large segmental mandibular defect. They have established from the literatury data and by their own experience of two cases, that the use of free fibula flap seems to be the best replacement method, when the bone defect is bigger then twelve centimeters.

Bone Transplantation↗

PubMed1996

[Inferior vena cava thrombosis developing in primary antiphospholipid syndrome].

Antiphospholipid antibodies predispose to venous and arterial thrombosis. The case of a sixteen-year-old boy with primary antiphospholipid syndrome is presented. Features of different organ involvement such as thrombosis of the inferior vena cava, pulmonary thromboembolism and cerebral involvement were present with thrombocytopenia and high titre of anticardiolipin in the patient's sera. On twelve-month follow-up while taking anticoagulant the patient was entirely free of symptomes though certain immunological findings showed slight positivity. However, considering the ARA criteria systhemic immunopathologic disorder could not have been proved. Other pathological conditions with anticardiolipin positivity were also excluded.

Adolescent↗

PubMed1995

Isolation of a full-length mitotic cyclin cDNA clone CycIIIMs from Medicago sativa: chromosomal mapping and expression.

Cyclins in association with the protein kinase p34cdc2 and related cyclin-dependent protein kinases (cdks) are key regulatory elements in controlling the cell division cycle. Here, we describe the identification and characterization of a full-length cDNA clone of alfalfa mitotic cyclin, termed CycIIIMs. Computer analysis of known plant cyclin gene sequences revealed that this cyclin belongs to the same structural group as the other known partial alfalfa cyclin sequences. Genetic segregation analysis based on DNA-DNA hybridization data showed that the CycIIIMs gene(s) locates in a single chromosomal region on linkage group 5 of the alfalfa genetic map between RFLP markers UO89A and CG13. The assignment of this cyclin to the mitotic cyclin class was based on its cDNA-derived sequence and its differential expression during G2/M cell cycle phase transition of a partially synchronized alfalfa cell culture. Sequence analysis indicated common motifs with both the A- and B-types of mitotic cyclins similarly to the newly described B3-type of animal cyclins.

Amino Acid Sequence↗

PubMed1995

[Intravesical electrostimulation for treatment of bladder dysfunction. Initial experiences after gynecological operations].

OBJECTIVE: We investigated the role of intravesical electrical stimulation in the treatment of voiding dysfunctions following major gynecologic surgery. METHODS: 19 female patients with sensory and/or motor voiding dysfunction following gynecologic operations underwent intravesical electrostimulation after failure of traditional treatments. Before and after therapy, urodynamic examinations were performed. The follow-up was 6-24 months. RESULTS: All cases of sensory bladder dysfunction were cured. Volumes of residual urine significantly decreased (mean 274 vs. 53 ml: p = 0.0003) and maximum detrusor pressure increased (mean 6 vs. 27 cm H20; p = 0.0007). An early start of therapy (within 6 weeks after surgery) resulted in a better outcome. CONCLUSIONS: Intravesical electrical stimulation was effective in the treatment of sensory and motor voiding dysfunctions following major gynecologic surgery.

Adult↗

PubMed1994

Chromosome aberration, sister-chromatid exchange, proliferative rate index, and serum thiocyanate concentration in smokers exposed to low-dose benzene.

Cytogenetical endpoints, i.e., chromosome aberration (CA), sister-chromatid exchange (SCE), and proliferative rate indexes (PRI), were measured in peripheral blood lymphocytes (PBL) of 42 workers exposed occupationally to low-dose benzene, and of 42 controls. The role of smoking habit as a confounding factor of genotoxic effects caused by occupational low-dose benzene exposure was also studied. The benzene concentrations in the ambient air samples varied from 3 to 20 mg/m3 (mean: 7 mg/m3). The continuous low-dose benzene exposure significantly increased the CA and SCE frequencies, but did not influence PRI. Smoking levels were characterized by subjective accounts and by serum thiocyanate concentrations (SCN). CA and SCE were not significantly increased in smokers compared to nonsmokers, but the differences were expressed to a greater extent in the case of measurement of SCN concentrations. Determination of SCN proved to be more objective in the assessment of genotoxic effects of smoking as a confounding factor of occupational low-dose benzene exposure.

Adult↗

PubMed1994

Evaluation of delta-aminolaevulinic acid excretion in random urine samples of children.

Urinary delta-aminolaevulinic acid (delta-ALA) excretion was evaluated in random urine samples of 191 healthy children, aged 2-14 years, with blood lead levels < 0.8 mumol/l (mean +/- SD: 0.34 +/- 0.13), erythrocyte zinc-protoporphyrin < 70 mumol/mol haem (mean +/- SD: 50.4 +/- 8.0) and blood haemoglobin > 6.8 mmol/l (mean +/- SD: 8.2 +/- 0.5). It was found that uncorrected delta-ALA concentration and delta-ALA/creatinine ratio are age-dependent, whereas the ratio of delta-ALA/logarithm of creatinine concentration (mean +/- SD: 55.3 +/- 13.5 mumol/log mmol) is independent of age and sex. The authors recommend the use of this parameter for the assessment of delta-ALA excretion in random urine samples in children.

Adolescent↗

PubMed1994

Radial forearm flap in maxillo-facial surgery.

Thirty consecutive patients treated with a free radial forearm flap were reviewed. This flap was used in the reconstruction of intraoral defect in 24 patients and of extraoral defect in 6 patients. There were no total or partial flap failures. Donor site complication included a partial loss of skin graft in 4 and radial fracture occurred in 1 patient. The authors considered the application of the radial forearm flap a reliable method for resurfacing large skin defect of the face. However, according to their conviction the most important field of the forearm flap is its use in intraoral reconstruction after pull-through operation. They drew attention to the limitation of the use of osteocutaneous flap in the replacement of segmental mandibular defect.

Adult↗