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Biomedical subjects

G Katona

Publications and source records attributed to G Katona.

At least 19 recordsLinked to original sources
PubMed2001

Comparative in vitro studies on native and recombinant human cationic trypsins. Cathepsin B is a possible pathological activator of trypsinogen in pancreatitis.

Hereditary pancreatitis, an autosomal dominant disease is believed to be caused by mutation in the human trypsinogen gene. The role of mutations has been investigated by in vitro studies using recombinant rat and human trypsinogen (TG). In this study we compare the enzymatic properties and inhibition by human pancreatic secretory trypsin inhibitor (hPSTI) of the native, postsynthetically modified and recombinant cationic trypsin, and found these values practically identical. We also determined the autolytic stability of recombinant wild type (Hu1Asn21) and pancreatitis-associated (Hu1Ile21) trypsin. Both forms were equally stable. Similarly, we found no difference in the rate of activation of the two zymogens by human cationic and anionic trypsin. Mesotrypsin did not activate either form. The rate of autocatalytic activation of Hu1Asn21 TG and Hu1Ile21 TG was also identical at pH 8 both in the presence and absence of Ca2+. At pH 5 Hu1Ile21 TG autoactivated about twice as fast as Hu1Asn21 TG. The presence of physiological amount of hPSTI completely prevented autoactivation of both zymogens at pH 8 and at pH 5 as well. Cathepsin B readily activated both zymogens although Hu1Ile21 TG was activated about 2.5-3 times as fast as Hu1Asn21 TG. The presence of hPSTI did not prevent the activation of zymogens by cathepsin B. Our results underlie the central role of cathepsin B in the development of different forms of pancreatitis.

Amino Acid Substitution↗
PubMed1999

[Objective audiologic assessment of children treated with amikacin].

Hearing assessment of 14 children suffered from urinary tract infection and treated by amikacin is reported. The dosage of amikacin was 7.5 mg/kg/daily for 10 days and the serum level of amikacin not exceeded the 35 mcg/ml. The aim of the study was on the one hand to determine the hearing damaging side effect of amikacin and on the other to assess the usefulness of objective methods for detection of hearing loss in this population. Authors used for screening a transient otoacoustic emission (TEOAE) during and after (2-4 weeks) therapy. If subjective and objective (TEOAE) methods gave a good result, no further checkup has considered as necessary, but if there were no evoked emission, acoustic brainstem response audiometry has been carried out for verification. It result no hearing loss could be detected in the measured specimen. In conclusion it has been stated that by proper dosage and serum level screening amikacin may no lead to hearing loss in children, and objective methods are valuable for hearing screening and monitoring of such population of children.

Adolescent↗
PubMed1998

[Aortopexy as a surgical treatment method in infantile congenital tracheo-chondrohypoplasia and tracheomalacia].

Congenital tracheal chondrohypoplasia and tracheomalacia have come to present a significant challenge in recent paediatric surgery. Authors shortly describe their pathology, pathophysiology, symptoms, diagnostic evaluation and outline the most frequency surgical procedures for them. The first three aortopexies in the authors' departments are described in this paper, with particular attention paid to the clinical problems of congenital tracheal chondrohypoplasia and tracheomalacia and the role of this method in surgical treatment, respectively. Aortopexy is quick, easy to carry out and atraumatic for the growing trachea. Authors want to draw attention to the fact that not every form of congenital tracheal chondrohypoplasia and tracheomalacia may be treated by conservative therapy, and that surgical treatment is recommended not only for life threatening forms, but for other severe forms as well.

Abnormalities, Multiple↗
PubMed1995

[Evaluation of hearing loss by means of inner ear acoustic emission in neonates treated with aminoglycoside].

Despite their ototoxic and other side effects, aminoglycosides are still widely used in the treatment of neonatal infections. A novel method for evaluation of hearing loss is distortion product otoacoustic emission (DPOAE). Physiologic acoustic energy-emission produced by sound stimulus in the inner ear is detected by DPOAE. Existing acoustic emission indicates the functional integrity of the inner ear. DPOAE was performed in 19 newborns treated with netilmicin for different infections. Serum netilmicin levels did not exceed 12 mg/l; renal functions were normal. Existence of emission was detected in 15 newborns. There was no emission found in 4 newborns unilaterally, which was fully restored in 2 months. In conclusion, aminoglycosides have no considerable ototoxic side effects. DPOAE is thought to be an objective, fast, and non-invasive method for hearing screening in the newborn period.

Anti-Bacterial Agents↗
PubMed1993

[Simultaneous occurrence of moyamoya disease and subclavian steal syndrome].

The authors present a case of moyamoya disease associated with subclavian steal syndrome. They could not find any report in literature about the combination of these syndromes. The Doppler, MR, and angiographic findings as well as the clinical importance of subclavian steal and moyamoya syndromes are briefly summarized.

Adult↗
PubMed1993

[Hearing loss resulting from purulent meningitis in the light of adjuvant dexamethasone therapy].

Results of objective audiometry of 109 infants and children after purulent meningitis are presented. Among them 17 patients got dexamethasone as a supportive therapy. There was no statistically significant difference in hearing loss between the dexamethasone-treated and the control group. (41 vs 43% sensorineural hearing loss respectively). Authors do not contraindicate the dexamethasone therapy in purulent meningitis because of its harmlessness and useful effect to the course of the disease but further investigations are needed for avoidance of hearing loss following meningitis.

Chemotherapy, Adjuvant↗
PubMed1993

Transitory evoked otoacoustic emission (TEOAE) in a child with profound hearing loss.

The case of a 3-month-old, prematurely born boy with auditory brainstem response (ABR), verified profound hearing loss and normal transitory evoked otoacoustic emission is presented. Isolated retrocochlear deafness which did not influence TEOAE is hypothesised as a possible cause. The critical evaluation of results when using TEOAE as a screening method is suggested.

Deafness↗
PubMed1992

[Otoacoustic emission audiometry in neonates and adults].

The authors discuss the clinical use of the otoacoustic emission audiometry. During the physiological process of sound amplification in the cochlea vibration energy escapes from the inner ear. By the analysis of this sound it is possible to gain information about the function of the cochlea. According to the experiences of the authors the method is extremely useful for screening audiometry in pathological and normal neonates. In adults it can be used for monitoring the cochlear function during ototoxic therapy or noise exposure.

Adolescent↗
PubMed1992

Epipharyngeal teratoma in infancy.

Epipharyngeal teratomas are rare congenital lesions that often cause respiratory distress, stridor at birth. The management of such anomalies should include establishment of secure upper airways, radiographic exclusion of midline CNS malformations and early surgical excision to prevent malignant transformation, asphyxia or permanent facial distortion. The diagnosis of congenital stridor, dyspnea and rhinitis should be performed very carefully.

Humans↗
PubMed1992

Regulation of proteinase activation in mammalian tissues.

A lot of new results have been published on activation of one or more proteinases in mammalian tissues. Explanation of proteinase activation without invasion of leukocyte during atrophy of mammalian tissues is the subject of the present study. The mechanism of activation process can be divided into two parts. The first one consists of modification of proteinases and their inhibitors by oxidation or reduction including oxygen free radical reactions. The second part of activation is a cascade or cycle including limited proteolysis of proenzymes and/or proteinase inhibitors. The hypothetic system of proteinase activation can give a hope for regulation of proteinase activity in mammalian tissues under pathological- or pathologic-like conditions as during exhausting exercise.

Animals↗
PubMed1991

Effect of vitamin E-deficiency on the activity of some lysosomal and non-lysosomal proteases in rabbit muscles.

The activity of different cathepsins and neutral proteinases was measured in normal and vitamin E-deficient rabbit muscles using specific substrates. Among the changes of enzyme activities in dystrophy caused by vitamin E-deficiency the increase in the activity of cathepsin B is the most striking. The activity of cathepsin H, both in the fast and slow muscles and that of MMP-ase in the slow muscle remains practically unchanged. Activities of other proteases significantly increase. The change in the activity of proteolytic enzymes in striated muscle of vitamin E-deficient rabbits seems to be selective. As a rule the increase in the activity is higher in fast than in slow muscles.

Animals↗
PubMed1990

[Surgical management of lateral facial clefts (macrostomia) by means of a rotational flap method].

Five cases lateral facial cleft (macrostoma) received in 30 years period are presented. The embriological background and the theories of the ethiopathogenesis are discussed. The authors' method to repair the abnormality--in spite of simple closure--is the modified Estlander flap surgery, which is described in details. The necessity of early treatment is emphasized. One case is presented in details.

Esthetics↗
PubMed1989

[Follow-up studies of patients with neonatal icterus using acoustic evoked potential audiometry].

Neonatal hyperbilirubinaemia is a common cause of sensorineural hearing loss. There is no exact method to detect the neurotoxicity of bilirubin. On the other hand the auditory pathway is known to be one of the most sensitive part of the CNS to this toxic agent. 39 one-year-old children were examined by BERA, who had had hyperbilirubinaemia in the newborn period. According to the risk factors the patients were divided into two groups but there was no significant difference in BERA changes. Two infants were found suffering serious hearing loss, who required hearing aids. Five more had some subclinical BERA changes. The authors emphasize the value of acoustic evoked potentials in evaluation infants after neonatal jaundice.

Audiometry↗
PubMed1989

Comparative investigation on the extractibility of acetylcholinesterase from normal and dystrophic muscles.

Following combined administration of nonionic detergent and collagenase considerable differences were observed in extractibility of acetylcholinesterase activity from normal and from dystrophic rabbit muscles. The results obtained in the experiments carried out on vitamin-E deficient rats corroborated the authors' previous experiences obtained in vitamin-E deficient rabbits. However, as to the effect of the detergent, considerable differences were observed between the two species. If one compares the activities referred to 1 g muscle or to the total tissue mass it is clear that primarily the concentration of acetylcholinesterase was increased. The activity measured in the presence of butyrylthiocholine increased only to small extent in vitamin-E deficient dystrophy.

Acetylcholinesterase↗
PubMed1989

[Biopsy of the external ear in diabetology].

In the introductory part the authors pointed to the need for the application of the morphologic method which would make possible the estimation of the existence and degree of miocroangiopathic changes. Microangiopathic changes were observed on the material obtained by skin biopsy of the auricle and the reason for selecting this localization was explained. It was performed in the representative sample consisting of 441 patients with diabetes mellitus and 92 persons with disturbed glucose tolerance and the objective indicators for small blood vessel changes were confirmed by the analysis of the material obtained by the method described. The possibility of the quantification of the degree of these changes was at the same time presented and illustrated. Finally, the authors came to the conclusion that reproducibility of these quantifications was satisfactory. Thereby, they were of the opinion that in their further work they could compare described and quantificated changes in respect to individual vital characteristics of the investigated group, the existence of factors considered risky for the appearance of diabetes mellitus complications and the degree of their development.

Biopsy↗
PubMed1989

Ankylosing spondylitis in the Mexican mestizo: patterns of disease according to age at onset.

We studied 87 Mexican mestizo patients (82 men and 5 women) with definite ankylosing spondylitis (AS) with particular reference to juvenile and adult onset types. HLA-B27 was present in 32 of 38. Forty-seven patients (54.0%) had onset before the age of 16 years and 40 (46.0%) thereafter. By the end of the 1st year of disease, main features included spinal involvement in 44 (50.6%), peripheral arthropathy in 57 (65.5%) and enthesopathy in 41 (47.1%). Frequency of these increased up to 100.0, 79.3 and 64.4%, respectively, through the course of the disease. Peripheral arthritis and/or enthesopathy occurred in 89.4 and 63.1% of juveniles and 37.5 and 27.5% of adults, respectively, while lumbar pain and/or stiffness occurred in 23.4% of the former and 82.5% of the latter during the first year of disease. Additional findings were high erythrocyte sedimentation rate, anemia and hypergammaglobulinemia. Uveitis was the commonest extraarticular manifestation occurring in 20.6%. Our data suggest that the clinical pattern of AS in our patients was influenced by both age at onset and sex distribution of the disease.

Adolescent↗
PubMed1988

Clinical experiences with the intramuscular injection of tiaprofenic acid in rheumatic diseases, with particular emphasis on time of onset and duration of the analgesic effect.

The efficacy of intramuscular tiaprofenic acid (TA) was investigated in 3 separate studies: a multicentre open study involving 487 patients with various rheumatic conditions: an open study of 31 patients with active osteoarthritis of the knee; and an open comparative study with ketoprofen involving 30 patients with acute gout. In each of the studies tiaprofenic acid was given at a dose of 200mg intramuscularly twice daily for 5 days. In addition to clinical efficacy and tolerance, the time of onset and duration of the analgesic effect were also assessed. Significant improvements in both pain intensity and inflammation were seen in 60 to 70% of all patients in the 3 studies (p less than 0.0001). Benefits from tiaprofenic acid injection were noted within 60 minutes by about 47% of the patients with acute gout and about 85% of the whole group of patients enrolled in the multicentre study. The analgesic effect lasted from 8 to 12 hours in about 52% of the latter patients, and the overall effect was assessed as either good, very good or excellent in 62.5 to 100% of patients. Results from the comparative study with ketoprofen in acute gout patients showed a better and faster beneficial effect in the group receiving tiaprofenic acid. Thus the intramuscular administration of tiaprofenic acid at a dose of 200mg twice daily for 5 days to 533 patients with different rheumatic conditions resulted in good analgesic and anti-inflammatory activities with a rapid and sustained effect, and was also well tolerated.

Adolescent↗