Biomedical subjects
Publications and source records attributed to K Tóth.
The authors present the computer dynamic pedobarographic analyse method of the diabetic foot with case reports. The diabetic foot is described in the literature by interdisciplinar teams, and the authors recommend this method in the identification of the high pressure areas of the foot. By this way the orthotic specialist can relieve these areas.
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1. We constructed a branching dendritic compartmental model of a CA3 pyramidal neurone, using experimental data from guinea-pig and rat cells obtained in vitro. The goal was to understand interactions between synaptic events impinging on dendritic branches and voltage- and calcium-dependent currents. The model contained sixty-four soma-dendrite (SD) compartments, an axon initial segment (IS), and four axonal compartments. There were six active conductances in the SD membrane, including a sodium conductance (gNa) and a high-threshold calcium conductance (gCa), with kinetic properties similar to those reported in a previous study. 2. The distribution of conductance densities across the IS and SD was adjusted by testing the model response to antidromic stimulation and current pulses or sustained currents injected into the soma or apical dendrites. As before, gNa was concentrated on and near the soma with lower density in the dendrites, while gCa had a higher density in apical dendrites than at the soma. 3. The model predicts that CA3 pyramidal neurones in media blocking synaptic transmission should fire a burst of action potentials following antidromic stimulation. This was confirmed experimentally in hippocampal slices. 4. Both in the model and in guinea-pig neurones, dendritic IPSCs can delay the onset of bursting. If an IPSC begins soon enough after the first fast action potential, the later burst envelope is attenuated. This effect results from suppression of dendritic Ca2+ electrogenesis. 5. The model predicts that an appropriately timed dendritic IPSC (after the first somatic spike but before the dendritic Ca2+ spike) may suppress the transient local [Ca2+] signal, while having a negligible effect on the electrical output of the neurone. This phenomenon has been reported in guinea-pig Purkinje cells. 6. We conclude that active dendritic currents are critical for regulation of the electrical output of CA3 pyramidal neurones. We suggest also that dendritic [Ca2+] signals might be controlled in individual dendrites independently of action potential outputs, an effect of possible importance for synaptic plasticity.
Recent data have proved that eosinophil cells actively contribute to the pathogenesis of numerous inflammations, including that of atopic dermatitis. The expression of the activated secreted forms of eosinophil cationic protein (ECP) as well as the determination of the rise and fluctuation of the ECP level of the serum make it very easy to follow their activity. Influencing the activation of the eosinophil cell may lead to important alterations in the treatment of these diseases.
The authors analysed in a retrospective study the clinical features, ECG and enzyme examinations of 97 patients who died in acute myocardial infarction proved by autopsy during 9 years in their department. They found the recognition rate of the acute myocardial infarction 73%, compared to the data of the literature good. There occurred 26 unrecognized myocardial infarctions, among which atypical clinical features were more frequent and typical ECG signs and enzyme values were less frequent, than among the recognized cases. In their earlier study 57% of the recognized acute myocardial infarctions occurred on the posterior wall, in the present one the rate of anterior and posterior cases was the same. In the earlier study from 95 posterior acute myocardial infarctions 35 (41%) were unrecognized, in present from 41 cases only 11 (27%). This 14% improvement in the recognition rate of the posterior myocardial infarctions should be attributed to the routine application of paravertebral ECG leads, but statistically was not significant.
A large number of noninvasive and invasive methods are used in establishing the diagnosis of ischemic heart disease. Coronary angiography is an expensive method and a restricted capacity exists in Hungary. The aim was to elaborate an optimal combination of different noninvasive methods which can select the real positive cases for coronary angiography with maximal efficiency. Besides routine examinations, dobutamine pharmacological test was carried out and hemorheological parameters were also determined. After evaluating the results, patients were divided into three groups: absence of IHD, probable IHD and IHD. The clustering of patients into these groups was made by using their multivariable classifier algorithm (PRIMA) and 27 different parameters of 44 patients were taken into account. The groups were well separable as the class-distances indicated. The maximal ST segment depression during exercise, pharmacological test and hemorheological parameters were found to be the most powerful discriminating factors. Though the validation of the results is still in progress, based on their previous data they feel that the examination of hemorheological parameters and the application of pattern recognition method can be useful in the diagnosis of ischemic heart disease.
We have developed a new immunoperoxidase "sandwich" staining method for amplified detection of P-glycoprotein (Pgp) that is suitable for use on formalin-fixed, paraffin-embedded (conventional) tissue sections. This was accomplished by substantially changing the procedure described by Chan (1988) so as to increase specific staining intensity and to decrease nonspecific background staining. To determine the most appropriate primary antibody for the assay, we compared the immunoreactivity of JSB-1, C494, and C219 monoclonal antibodies recognizing internal epitopes of Pgp, and MRK16 and 4E3 monoclonal antibodies recognizing external epitopes of Pgp. Paraffin sections of Pgp-positive normal human tissues (adrenal, liver, kidney, and brain), of renal tumors, and of cell pellets of sensitive and multidrug resistant human tumor cell lines (MCF-7, KB) were used for comparisons. Immunostaining was excellent with JSB-1, moderate with C494, and very weak with C219. MRK16 and 4E3 showed no reaction. Nonspecific background staining was reduced by 1) omitting immunoglobulin G from secondary antibodies; 2) decreasing the concentration of peroxidase-antiperoxidase complex; and 3) utilizing casein solution for blocking and washing. Pretreatment of sections before immunostaining was also simplified. Using JSB-1, the threshold for detection of elevated Pgp corresponded to less than two-fold relative resistance to doxorubicin. Applying this method, we found two of 26 non-small cell lung cancers were positive for Pgp, consistent with previous results of others using frozen sections. This new immunoperoxidase sandwich staining method using JSB-1 now allows reliable Pgp detection in sections of formalin-fixed, paraffin-embedded (archived) surgical specimens and small biopsy materials commonly used for diagnostic purposes.
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Authors describe an extremely rare case of simultaneous bilateral posterior dislocation of the shoulder. The referring international literature and that of this country is surveyed. In the latter no paper, describing bilateral posterior dislocation of the shoulder was published. They have found this case, because of its rarity, worthy of publication.
During 6 years (1980-1985) 1876 patients with fractures of the distal end of the radius were treated in the County Hospital-Polyclinic Unit "Kaposi Mór". In this paper 302 cases, reduced and pinned with K-wire are discussed. 247 could be controlled 5-10 years after the injury. On the basis of the results in unstable fractures of the distal radial end, susceptibles for redislocation closed pinning with K-wire, following correct reduction is suggested.
In the Department of Traumatology of the County Hospital "Kaposi Mór" 150 children with supracondylar fracture of humerus were treated during 10 years (1980-1989). 119 cases reduced and pinned with percutaneous Kirschner wire are dealt with. 98 cases could be controlled 2-10 years after the accident. The importance of urgent treatment is stressed. The urgent reduction and the closed pinning with Kirschner wire are thought to be an efficient prophylaxis against Volkmann's ischaemic contracture and varus deformity, caused by secondary movements.
Morphologically a synapse consists of a presynaptic release site containing vesicles, a postsynaptic element with membrane specialization, and a synaptic cleft between them. The number of release sites shapes the properties of synaptic transmission between neurons. Although excitatory interactions between cortical neurons have been examined, the number of release sites remains unknown. We have now recorded excitatory postsynaptic potentials evoked by single pyramidal cells in hippocampal interneurons and visualized both cells using biocytin injections. Light and electron microscopy showed that excitatory postsynaptic potentials were mediated by a single synapse. We also reconstructed the entire axon arborization of single pyramidal cells, filled in vivo, in sections counterstained for parvalbumin, which selectively marks basket and axo-axonic cells. Single synaptic contacts between pyramidal cells and parvalbumin-containing neurons were dominant (> 80%), providing evidence for high convergence and divergence in hippocampal networks.
The termination pattern of hippocamposeptal nonpyramidal cells was investigated by injecting Phaseolus vulgaris leucoagglutinin (PHAL) into stratum oriens of the CA1 region. Electron microscopic analysis showed that the majority of the anterogradely labeled boutons formed symmetric synapses with dendrites and occasionally with cell bodies located in the medial septum-diagonal band of Broca complex. We have demonstrated with postembedding GABA immunocytochemistry that the majority of PHAL-labeled axon terminals were GABAergic. The neurochemical character of the postsynaptic target cells was also investigated using immunocytochemical double staining. Our data showed that the majority of the labeled hippocamposeptal axons innervated parvalbumin-immunoreactive cells representing GABAergic projection neurons, and a smaller number of contacts were found on ChAT-positive neurons. Septohippocampal neurons identified by retrograde HRP transport were also shown to reactive direct hippocamposeptal input. According to recent results, the lateral septum is unlikely to relay the hippocampal feedback to the medial septum; therefore, the direct hippocampal projection to the medial septum, arising from GABAergic nonpyramidal cells, seems to be the only feedback pathway to the area containing septohippocampal neurons. A novel circuit diagram, based on our recent morphological-immunocytochemical findings, is shown for the synaptic organization of the septo-hippocampo-septal loop. We suggest that the GABAergic hippocamposeptal feedback controls the activity of septal (mostly GABAergic) projection neurons as a function of hippocampal synchrony. The newly discovered reciprocal interactions may give a better insight into septohippocampal physiology.
In the Department of Traumatology of the "Kaposi Mór" County Hospital 213 patients with the fracture of the proximal end of the tibia were treated during 10 years (1980 + 89). 165 operated cases are analysed, 120 of them could be controlled 1.5-9 years after the operation. The importance of the reconstruction of the articular surfaces is stressed and attention is called to the increased possibility of infection in these operations.
First-pass radionuclide angiocardiography (FPRNA) with 99mTc-albumin was performed in 19 patients with cor pulmonale. Pulmonary circulation time (PCT), mean transit time (MTT), pulmonary stagnation index (PSI) were calculated from the time-activity curves for the estimation of cardiopulmonary circulation. Whole blood viscosity (WBV), plasma viscosity (PV) and hematocrit (HTC) were also measured on the same day. Significant prolongation of all parameters was observed (WBW: 5.04 +/- 1.19 mPas; PV: 1.36 +/- 0.17 mPas; HTC: 47.6 +/- 2.37%; PCT: 7.10 +/- 2.15 s; MTT: 9.33 +/- 4.11 s; PSI: 1.30 +/- 0.37) in patients with cor pulmonale. Significant positive correlations were found between PCT and WBV (r = 0.552; 0.001 < P < 0.01), MTT and WBV (r = 0.34; P < 0.05), furthermore between PCT and HTC (r = 0.356; P < 0.05). The results suggest that hemorheological parameters may influence the results of FPRNA, therefore, they should be determined in addition to the radionuclide study.
The authors practiced carotis duplex scanning examinations on 60 patients having lower limb artery disease. The patients were grouped according to, having cervical bruit or not. In the first group 100% had stenosis while in the second group had only 13.3%. Furthermore the stenosis--plack were analysed according to the severity of the lower limb artery disease. The severity of stenosis can be found in group "A" (bruit exists) and group "B" (no bruit) accordingly to the Fontaine stages. Stenosis higher then 50% was found in group "A" 3 in Fontaine stage II, and 10 in Fontaine stage III. While in group "B" there were no stenosis in Fontaine stage II, and 4 in Fontaine stage III. Out of thet not exceeded 3, 50%, and 1 was subtotal. Likewise, difference can be found of the presence of placks partly in the two groups, partly in the point of view of the stages of Fontaine. There are in group "A" 23 cases with 48 placks, in group "B" 14 cases with 23 placks. Among the patients of group "A" in 10 cases with were in Fontaine II, and 13 in Fontaine III stage. In group "B" 5 were in Fontaine II, and 9 in Fontaine III stage. Authors are calling the attention, that according to their own data, and the sensitivity of duplex scanning this is the most proper examination for recognising the carotid artery sclerosis which is associated with lower limb artery disease.
A model system for 3-dimensional "native-state" culture of tissues on collagen gels (Proc. Natl. Acad. Sci. USA 86:2013-2017; 1989) has been applied in this study to histologically normal human renal cortical tissue from 11 patients undergoing nephrectomy for renal cell carcinoma elsewhere in the kidney. Microbial contamination occurred in 12/90 cultures, the rest (78) were studied by visual inspection, histology, immunohistochemical analysis for pankeratin (epithelial cell origin), vimentin (mesenchymal cell origin), and p-glycoprotein (associated with proximal tubules), transmission electron microscopy (EM), incorporation of tritiated thymidine (3HTdR). In the first 10 days, explants showed 3HTdR-labeled cells in tubule structures. The surrounding gel was invaded by cells forming tubule structures, sometimes with basement membrane. Some of these cells showed labeling by 3HTdR and immunostaining positive for pankeratin and p-glycoprotein. EM showed well-polarized epithelial cells in tubule structures with tight junctions, interdigitating lateral processes, and microvilli characteristic of proximal and distal convoluted tubules. 3HTdR-labeled cells in tubule structures were observed even 2 mo. after Passage 1, 6 mo. after the initial explantation. Tubule growth was most active and fibroblast proliferation was negligible from 2 to 4 wk postexplantation. The proliferation of tubulelike cells and formation of tubulelike structures in this system represents an opportunity to study human renal cortical tissue in vitro, under conditions more closely resembling in vivo circumstances than are present in other in vitro systems suitable for long-term study. This model has potential use for in vitro toxicology studies and studies of renal physiology.
Calbindin D28k-containing non-pyramidal cells were found in all layers and subfields of the hippocampus, with the highest frequency in stratum radiatum of the CA1-CA3 subfields. A large number of these neurons had a vertically oriented dendritic tree, often restricted to to stratum radiatum. In stratum oriens and near to the border of strata radiatum and lacunosum moleculare cells with horizontally running dendrites were also found. Multipolar cells were most common in stratum radiatum of the CA3 region. The GABAergic nature of the calbindin D28k-containing non-pyramidal cells was studied using the "mirror" technique. Adjacent thick sections were immunostained for calbindin D28k and GABA, and halved neurons were identified on the common surfaces. The majority of calbindin D28k-containing non-pyramidal cells were shown to be GABAergic. The GABA-negative calbindin cells were found in relatively large numbers in stratum oriens of the CA1-CA3 region, and occasionally in strata radiatum and pyramidale of CA2, and in stratum radiatum of the CA3c region near to the border of the dentate hilus. However, even in these cells a weak immunostaining, only slightly but consistently above background level, was always observed. Earlier studies have demonstrated that the somata of GABAergic neurons with distant projections may contain a level of GABA that is below the detection threshold of immunocytochemistry. Here we provide direct evidence that the calbindin-containing non-pyramidal cells were among those projecting to the medial septum. Following horseradish peroxidase injections into the medial septum 80% of the retrogradely labelled non-pyramidal cells were found to be immunoreactive for calbindin D28k, and 20% contained neuropeptide Y. These results suggest that the calbindin D28k-containing and apparently GABA-immunonegative non-pyramidal cells in stratum oriens of the CA1-CA3 regions may also be GABAergic, but have a distant projection, that is, to the medial septum.