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Biomedical subjects

J Tóth

Publications and source records attributed to J Tóth.

At least 19 recordsLinked to original sources
PubMed1996

Endogenous opioid mechanisms in hypothalamic blood flow autoregulation during haemorrhagic hypotension and angiotensin-induced acute hypertension in cats.

The influence of naloxone-induced general opiate receptor blockade on hypothalamic blood flow autoregulation was investigated in anaesthetized, artificially ventilated, temperature controlled cats. In order to study the changes of the hypothalamic blood flow (H2-gas clearance technique) at the lower limit of autoregulation systemic arterial pressure was reduced in a stepwise manner to 100, 80, 60 and 40 mmHg, by haemorrhage. Autoregulatory mechanisms of the hypothalamic vessels remained effective and hypothalamic blood flow showed no significant reduction until the arterial pressure was reduced to 60 mmHg in the vehicle-treated control cats. General opiate receptor blockade by 1 mg kg-1 mL-1 i.v. injected naloxone resulted in a significant reduction of the autoregulatory capacity of the hypothalamic vessels: the blood flow followed passively the arterial pressure fall already from 100 mmHg mean arterial pressure. The effect of opiate receptor blockade on the upper limit of the autoregulation was studied during acute arterial hypertension, induced by angiotensin-II infusion (25 micrograms 0.1 mL-1 min-1 i.v.). Hypothalamic blood flow remained remarkably steady following angiotensin-II infusion in the saline-treated control animals. Naloxone pretreatment (1 mg kg-1 mL-1 i.v.), however, induced a significant downward shift of the upper limit of the autoregulation, and hypothalamic blood flow started to increase in the 125-145 mmHg arterial pressure range. The narrowing of the autoregulatory range following general opiate receptor blockade suggests an important role of endogenous opioid peptides in hypothalamic blood flow autoregulatory mechanisms both in hypotensive and in hypertensive conditions.

Angiotensin II↗
PubMed1995

Impaired microbicidal capacity of mononuclear phagocytes from patients with type I Gaucher disease: partial correction by enzyme replacement therapy.

The higher susceptibility to serious bacterial infections in patients with Gaucher disease (GD) may be due in part to defective function of phagocytic cells. We studied five patients with GD (type I) and examined the ability of granulocytes and mononuclear phagocytes from these patients to phagocytose and kill Staphylococcus aureus and to generate superoxide anion (O2-) on stimulation with fully opsonized bacteria. Serum-opsonized staphylococci were ingested equally by phagocytic cells from patients and controls. In the presence of normal serum, the extent of killing of S aureus and the release of O2- by granulocytes over incubation periods of 60 minutes and 30 minutes, respectively, were also equivalent for patients and controls. However, we found that killing of viable bacteria and release of O2- by the patients' monocytes was significantly lower than that in cells from controls (P < .05 for both). The magnitude of differences in killing and O2- release between patients' cells and those from controls was even more profound with monocyte-derived macrophages. Enzyme augmentation with macrophage-targeted glucocerebrosidase preparation for 6 months at doses from 7.5 to 10 U/kg/wk resulted in significant increases of functional activities and O2- generation of monocytes and macrophages along with hematologic and hepatosplenic improvements. These data suggest that mononuclear phagocytes from GD patients are defective in their ability to kill bacteria and to generate reactive oxygen intermediates. Our data also suggest that enzyme substitution may improve functions of monocytes and macrophages in patients with GD that should make them more resistant to severe bacterial infection.

Gaucher Disease↗
PubMed1994

[Non-surgical approach to the treatment of vesico-ureteral reflux in childhood].

The authors report about their point of view, based on their experience treating children with vesicoureteric reflux (VUR) in the last two decades. 812 children were treated for VUR between 1973-1992. In 62 (7.6%) due to the parenchymal damage, primary nephrectomy was made, antireflux operations were done in 227 (30.3%). Without surgery, recovery or significant improvement was achieved in 523 children (69.7%). The basis of the good results with conservative therapy is in their opinion the thorough knowledge of the function of the urinary organs, especially of the urinary tract, and the precise detection of the pathophysiological processes leading to VUR. The conditions in which antireflux surgery is avoided, are discussed in details, emphasizing the situations and methods eventually leading to mistakes, e. g. the improper judgement of VUR detected during acute pyelonephritis or during an incorrectly performed micturition cystography, and the undiagnosed damaged bladder function. Essential is therefore to clarify the etiology of the VUR and the compensated/uncompensated state of the urinary tract, the clinical condition of the child. Antireflux operation is necessary only if in the renal parenchymal damage the role of the VUR is obvious and it can be prevented only with surgery.

Adolescent↗
PubMed1994

[Clinical significance of steroid receptors in breast cancer].

The steroid receptor determination (first of all estrogen receptor--ER--) of the breast cancer tissue has become an important factor for prognostication and treatment. Authors from the Surgical Department of the National Institute of Oncology provide a biostatistical survey of their 727 breast cancer patients. Following factors proved to have significant impact on the prognosis: positivity of ER, the quantitative value of ER, ER vs. lymph node status, ER vs. DFI, ER and the site of metastases and the hormone therapy. The progesterone receptor (PR) provides indication in case only for DFI for metastases. However, in this very respect it has a more significant value than that of ER. Multidimensional analysis has shown that the most important prognostic factors are the lymph node status, patient's age, size of the tumour and the ER value.

Breast Neoplasms↗
PubMed1994

[NK cells and their characteristics and immunogenetic aspects].

This review summarizes knowledge of history and development of the "new" biological phenomenon. NK cells play a pivotal role in immune surveillance against tumors and virus-infected cells. They are also involved in natural resistance to bone marrow transplantations and in the regulation of the growth and activity of immunocompetent and hematopoietic cells. Unlike cytotoxic T lymphocytes NK cell activity is not dependent on thymus maturation and an expression of class I MHC antigens. They lack immunological memory and develop directly from precursor cells of the bone marrow. The lytic activity of NK cells is associated with the population of large granular lymphocytes (LGL). In human peripheral blood there is about 5% of LGL. A great deal of the study is given to still actual about the possible role of class I MHC antigen expression in regulation of NK-cell cytotoxicity. (Fig. 1, Tab. 2, Ref. 118).

Animals↗
PubMed1994

[NK cell activity and inhibition by anti-HLA monoclonal antibodies].

The authors followed the effect of anti-HLA class I and II monoclonal antibodies on cytotoxic activity of human NK cells. The mAb 18/5, 23/9 and beta 2m (anti-HLA class I) as well as mAb 20/DR, 30/DR, 13/DP and FB6/DP (anti-HLA class II) were used. Both groups of the antibodies were either tested directly during the cytotoxic test, or NK cells were pre-incubated with them. The application of the antibodies results in an inhibition of NK cell activity by the average of one third. However, the pre-incubation of NK cells with the mAb has not been so unambiguous. On the other hand, the application of anti-HLA class I and class II mAb had no effect on the interaction of NK cells with their target cells. We can conclude that HLA molecules might play a role in the late stages of the cytolytic mechanism of NK cells. (Fig. 1, Tab. 2, Ref. 21.)

Antibodies, Monoclonal↗
PubMed1994

[NK cell activity and association with the HLA class I antigen complex].

To contribute to the genetic regulation of NK cell cytotoxic activity an association between HLA antigens and a level of cytolysis of target cells (K-562) have been followed. By investigating of NK cell cytotoxic activity in 183 HLA-typed healthy persons it was found that high levels of cytolytic function of NK cells were associated with the antigens of HLA-B8, HLA-B27, HLA-B40, and HLA-B44 as well as the HLA-A2,-B12 phenotypes (in male only). It was also found that low NK cell cytotoxic activity was significantly correlated with homozygosity at HLA loci. These results suggest that HLA genes or genes linked with them may control NK cell cytotoxic functions in man. The authors have also suggested that above mentioned HLA-B antigens might belong to the activating receptor family of NK cells. (Tab. 7, Ref. 48.)

Cytotoxicity, Immunologic↗
PubMed1994

[Combined effect of CO2 and Nd:YAG laser on the rat tongue].

Authors fixed the handpieces of a CO2 and Nd:YAG lasers together so, that the two laser beams had a common focus. It is histologically proved in this paper, that the combined effect fulfills all the known advantages of either of the two lasers, while disadvantages are largely eliminated. Based on these results the device is planned to be introduced in oral surgery.

Animals↗
PubMed1993

[Experience with rapid gallstone dissolution].

The authors describe results of rapid percutaneous litholysis in 26 patients with gallbladder stones. The stones were completely dissolved in 17 cases and became free of symptoms 7 patients. The mean hospitalization time was 3 days, in eight cases only 1 day.

Adult↗
PubMed1993

Masking of HLA class I molecules expressed on K-562 target cells can restore their susceptibility to NK cell cytolysis.

The aim of our study was to follow whether class I HLA antigens play a role in the susceptibility of K-562 target cells to NK cell lysis as well as in the interaction between NK and target cells. After K-562 cells were treated with rIFN-gamma, HLA class I antigens appeared on their surface. Those HLA class I+, in comparison to HLA class I-, K562 target cells became about 40-50% less susceptible to NK cell cytolysis. This influence of HLA class I antigens was abrogated when class I+ K-562 cells were incubated with anti-HLA class I monoclonal antibodies Bra 23/9. The restoration of susceptibility of these targets to NK cell cytolysis was not caused by ADCC mechanism as determined by F(ab')2 fragments or by mAb CD16. Further, the percentage of conjugates between effector and target cells was not significantly altered neither when HLA class I antigens appeared on the surface of K-562 target cells nor when HLA class I+ K-562 cells were incubated with anti-HLA class I monoclonal antibodies. To study this question, we used a different approach because both expression of HLA class I molecules and their masking with appropriate monoclonal antibody were done by means of the same cell line of target cells.

Cytotoxicity, Immunologic↗
PubMed1993

Oncogene patterns in breast and ovarian carcinomas.

Nineteen paraffin-embedded breast cancer tissue samples selected for long survival (more than 5 years) were analysed for detecting the amplification of the c-erbB-2 (Her-2/neu) oncogene by Polymerase Chain Reaction (PCR). Strong correlation was elucidated between c-erbB-2 amplification and survival; such correlation was also observed with histopathologic types and nuclear grading. Because of the similarity of the breast and ovarian cancer in the etiology of the diseases, amplification of c-erbB-2, c-myc and Ki-ras genes was examined in 32 ovarian carcinoma samples (stage I-IV). In ovarian carcinomas c-erbB-2 amplification occurred in 34% (11/32) of the fresh tumour samples, and correlation between amplification and clinical staging at P < 0.05 significance level was observed. Amplification of c-myc was detected in 9% (3/32) and none of the tumours showed amplification of Ki-ras.

Base Sequence↗
PubMed1992

Testosterone secretion in children with undescended testis.

Testicular testosterone (T) production was examined in thirty boys with undescended testes (UT) following the administration of 4500 U gonadotropic hormone. Twenty boys had bilateral UT and ten had UT plus hypospadias. As for possible causes of reduced Leydig cell activity it was investigated whether the testis was (1) hypoplastic; (2) abnormally fused with the epididymis; (3) located in the abdomen; (4) or UT was associated with hypospadias. Average T values were significantly lower when the testicle was hypoplastic or its fusion with the epididymis was imperfect; but remained largely undiminished when the testicle was located in the abdomen or when UT was combined with hypospadias. The occurrence of both pathologic and physiologic T reactions in each of the four groups suggests that the population of UT children is heterogeneous, probably due to differences in aetiology and in intrauterine hormonal processes. In the case of UT and hypoplasia the time and method of operation (orchidopexy) must be selected with utmost care, bearing in mind that an originally small testicle with impaired T secretion may become physiologic by the time of puberty.

Abnormalities, Multiple↗
PubMed1992

Results of surgical treatment in children with bladder exstrophy.

A series of 42 children (30 boys and 12 girls) underwent surgery for bladder exstrophy between 1972 and 1989. Primary bladder closure was performed in 11 patients and was successful in 6. Four of these children are about 2 years old and so it is not yet possible to assess their continence. Ureterosigmoidostomy was performed in 35 children, one of whom was converted to cutaneous ureterostomy. Follow-up ranges from 2 to 20 years (average 9 years 3 months) and 50% of the patients are symptom-free. The most frequent problems were acidosis and urinary tract dilatation. Other complications, such as hypokalaemia and pyelonephritis, were seldom seen. Although ureterosigmoidostomy has some disadvantages, our patients have adapted well and lead a normal life.

Adolescent↗
PubMed1992

[Comparative light microscopic, scanning-electron microscopic and electron microscopic studies of the effect of experimental interventions by surgical scalpel, electrocautery and CO2-laser beam in the oral cavity].

Tissue effect interventions by means of surgical scalpel, elecrtokauter and CO2-laser ray in the mouth cavity of 20 white rats has been examined. According to their light microscopical examinations both the laser and the electrokauter caused thermal injuries taking place in typical zones while by the scalpel the cut surface in rendered ragged. The band-width of the thermoinjury caused by the kauter is a multiple of that caused by the laser. It has been proved by means of scanning electronmicroscopical examinations that interventions by means of laser result in sharp wound borders, the wounds cut by means of kauter are characterised by the presence of a great number of carbonized specks while by means of the scalpel a mechanical tear of the tissues is brought about. By means of electronmicroscopical examination the characteristics of the typical thermoinjured zones are described. It has been established that in the case of laser the injury of the ultra-structure extends to 400 microns while in case of electrokauter it reaches a width of 1500 microns. The excellent haemostatic effect brought about by the thermoeffect by means of the laser, in contrast to the broad thermoinjured zone caused by the kauter, is obtained at a very mild thermoinjury.

Animals↗
PubMed1991

[Chronic gastritis and the presence of Helicobacter pylori in patients with non-ulcerative dyspepsia].

After definition in the group of the non ulcer dyspepsia (NUD) can be counted all those patients at whom beside the dyspeptical complaints, the radiological and endoscopical examinations didn't show ulcerative changes. The authors made biopsy 550 times on the occasion of 1390 gastroscopical examination (39.5% of the cases). The histological examination showed chronic gastritis in 372 cases (26.7% of all the examinations, 67.6% of the histological examinations). At this group of patients the dyspeptical complaints gave the principal indication of gastroscopical examination. Also it was examined the presence of dysplasia and intestinal metaplasia beside the different severity grade of chronic gastritis. The presence of Helicobacter pylori (Hp) was examined by histological methods. Hp positivity was noticed in 16.4% in the upper group. The authors made Hydrogen-breath examinations in 34 cases between patients with NUD. The results of Hydrogen-breath examinations also raise the multifactorial nature of the NUD. On the basis of examinations chronic gastritis and CP infection can form subdivisions in the heterogenic group of patients with NUD. For exacter judgement of Hp pathogenicity are needed further and wide-spread examinations. The authors would like to call the attention to the indispensability of the biopsy during the gastroscopical examination.

Chronic Disease↗
PubMed1991

[Comparative study on wound healing in the oral cavity following experimental surgery using a scalpel, electrocauterization and CO2 laser beam].

In the mouth cavity of white rats lesion was created by means of surgical scalpel and electrokauter the course of the wound healing was observed on basis operations of various types (coagulation, vaporization, excision) as well as scalpel and electrokauter the course of the wound healing was observed on basis of histological examination of biopsies taken on the second, fifth, tenth, twentieth and fortieth day. It was verified that the wound healing is excellent after all three types of laser surgical intervention and is significantly more favourable than in case of electrokauter. The course of healing is finished during 3 weeks after coagulation and vaporaziation, and during 4 weeks after excision. The new epithelium layer became thinner than the original while the submucosa became twice as thick. The laser treated surfaces are protected by coagulation proteins, the wound edges are sharp, the amount of the cicatrice tissue formed after the wound healing is less than after the employment of the scalpel and the electrokauter.

Animals↗
PubMed1991

[Increased numbers of large granular lymphocytes in the peripheral blood in selected inflammatory rheumatic diseases].

In six patients with selected inflammatory rheumatic diseases the authors found increased numbers of LGL in the peripheral blood. Concurrently in these patients an increase of lymphocytes with the CD57 sign was found. In one patient with rheumatoid arthritis more detailed analysis revealed a reduced number of lymphocytes with sign CD16. In this patient in the peripheral blood cells with signs CD3+ and CD57 were found and the function of NK cells was markedly reduced. The clinical course of the disease in the patients was severe, in particular in SLE, where in three patients the disease was associated with the development of lupus glomerulonephritis. The patients were treated by immunosuppressive therapy. The authors reflect on the causes of the increase of LGL cells and do not rule out the possible presence of a serious immunoregulatory disorder between T and B lymphocytes.

Adult↗