Genetic factors of importance for beta-cell proliferation.
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Animals↗
Biomedical subjects
J Mares
Publications and source records attributed to J Mares.
A chimera between platelet-derived growth factor beta-receptor and fibroblast growth factor receptor-1 stimulates pancreatic beta-cell DNA synthesis in the presence of PDGF-BB.
This study was undertaken to characterize the expression of a chimeric growth factor receptor composed of the extracellular and transmembrane domains of the platelet-derived growth factor (PDGF) beta-receptor (PDGFR-beta) fused to the intracellular domain of the fibroblast growth factor receptor-1 (FGFR-1) and to assess its effect on the growth potential of pancreatic islet cells. For this purpose rat pancreatic islets or monolayers of pancreatic islet cells were transfected with recombinant DNA constructs coding for the PDGF B-chain, the PDGFR-beta, the FGFR-1 and the chimera between PDGFR-beta and FGFR-1. DNA synthesis, monitored as the percentage of labelled nuclei and [3H]thymidine incorporation, was stimulated in pancreatic islet cells cotransfected with the constructs coding for the PDGF B-chain and the PDGFR-beta or the chimeric PDGFR-beta/FGFR-1 as compared with that determined after transfection with control plasmid. PDGF-BB stimulated DNA synthesis when islet cells had been transfected with PDGFR-beta or PDGFR-beta/FGFR-1. Cotransfection of the PDGFR-beta and the chimeric PDGFR-beta/FGFR-1 constructs attenuated the stimulation of DNA synthesis in response to PDGF-BB. Receptor binding studies showed binding with a Kd of 0.7 nM to the chimeric receptor. The present findings show that when the chimeric PDGFR-beta/FGFR-1 construct is expressed in beta-cells it is efficient in increasing DNA synthesis when stimulated with ligand.
Animals↗
[A textbook presentation of muscle contraction. Contribution by the editor].
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Animals↗
Communication with patients as a problem in undergraduate medical education.
The work is based on the following concepts: communication with patients ceases being a matter of experience learning only (the trial and error method) and should become a part of systematic training; it should not be included only into continuous education of graduated physicians but must be gradually introduced into undergraduate education as well; it is not an optional activity which may but may not be performed by physicians, but it is a specific component of their clinical competence. Today attempts to instruct medical students in communication with patients and their relatives are being made at many medical schools all over the world. Reports on such instruction are, however, scattered in various journals or in internal publications published by universities, faculties and clinics. Thus they are not available very easily. If there exist some survey works, they are mostly conceived on the national level. The objective of the study presented here is to show a comparatively comprehensive survey dealing with the medical student instruction on the international level, analyze trends in development and identify problems that have not been solved so far. The work consists of five chapters. The first one gives a short survey of current concepts in communication with patients reaching beyond the traditional training in taking medical history. Among others, the following factors are included here: explanation of both diagnostical and therapeutical methods to the patient, informing the patient about results obtained from the examination, telling him or her general conclusions and recommendations, informing patients of social associations of the disease, developing in the patients those attitudes which support their cooperation with physicians and the patient's will to live, ability to treat serious and terminal patients properly, ability to treat patients' relatives and communicate with other members of a medical team. The second chapter shows current attempts to train the medical student-patient communication in Czechoslovakia, especially at Charles University. Third chapter describes how medical students in the former USSR were instructed, especially at medical schools in Moscow. This kind of information is still difficult to be had for people from abroad. The fourth chapter is the most important. Current attempts to train medical students in communication with patients in Europe, North and South America, Asia, Africa and Australia are described there. Reference frames in which the instruction takes place (medical, educational, psychological frames) are studied.(ABSTRACT TRUNCATED AT 400 WORDS)
Communication↗
Endocytotic activity of the presynaptic membrane and the morphometric differences of cortical synapses during the excitability changes in the initial phases of kindling.
Cortical sensorimotor areas of the laboratory rats was repeatedly stimulated at 10 min intervals. It led to progressive lengthening of the self-sustained after discharges (SSAD). Ten minutes after termination of the third SSAD the synapses of type I were examined. The ten minutes interval corresponds in electrophysiological experiments with a marked increase of excitability of the investigated cortical area. At the some time, it coincides with the intensification of endocytotic activity on the presynaptic membrane, and with an increase of complex and dense-core vesicles. The exocytotic activity was not changed. The area of the presynaptic elements increased together with their perimeter and maximal diameter. Mitochondria within the presynaptic bags had larger section area. Also the postsynaptic elements became larger, their section area, perimeter and maximal diameter increased. We consider the theory of presynaptic membrane recycling, ion permeability changes, activity of proteosynthesis and the role of contractile proteins during the repeated hyperfunction.
Animals↗
[Changes in the configuration of synapses in the cerebral cortex in laboratory rats after termination of epileptic seizures during kindling].
The sensorimotor area of the cerebral cortex of the laboratory rat was repeatedly stimulated by electric current after 10-minute intervals which led to the development a gradual prolongation of self-sustained after-discharges (SSAD). One and 10 minutes after termination of the third SSAD the authors analyzed under the electron microscope synapses type I after to Gray from the second cortical homotopic area of the unstimulated hemisphere. They evaluated the curvature of the active zone of synapses. Evidence was provided that one minute after termination of the fit the number of negatively curved synapses increased and the number of synapses with a straight active zone decreased. The number of synapses with a positively curved active zone does not change. Ten minutes after termination of SSAD in the experimental animals the number of positively curved elements declines and the number of negatively curved synapses increases. There is no significant difference in the number of synapses with a straight active zone. The authors discuss possible functional consequences of the mentioned changes.
Animals↗
Triple drug therapy in haploidentical living related and cadaveric kidney transplantation.
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Azathioprine↗
Students' rating as one of the methods for instruction evaluation.
World-wide knowledge in this field is summarized in this study. The information may be useful for university teachers, academical officials and people dealing with measuring quality of higher education. First part of the study is general. Terms of educational effectiveness, instructional effectiveness and pedagogical evaluation are characterized there. Differences between summative and formative evaluations are discussed. Three commonest approaches to the evaluation of higher education quality are analyzed (investigation of university prestige, study of objective indicators, correlation studies). It is emphasized that instructional quality is a relative term, multifaceted, with subjective elements and complexly conditioned. One of possible models for university instruction evaluation is presented and its eight variables are specified. A general strategy of such evaluation is described and attention is drawn to the fact that every assessment is based on a rough or clear concept of the best instruction under given conditions. Basic rules for instruction evaluation are stipulated as well as important principles which should be respected by anyone who wants to choose the most suitable method of university instruction evaluation. Second part of the study is special. The only method--evaluation using rating scales--is focused on. Students are said to be the most frequent evaluators of university instruction quality. Objections to the rating scales and negative experience with their non-professional application are presented. The construction of rating scales is described, i. e. the planning of the content and purpose of the scale, preparation of a blueprint, its practical verification and statistical interpretation. Practical instructions including an appropriate moment of administration, necessary number of raters, statistical analysis of significance of the results obtained are explained here for those who want to use the scale in their routine practice. Information about factors which may affect or even bias the assessment, i. e. validity of the results, is summarized. Procedures enabling a statistical analysis of the reliability of results are discussed. A not very clear problem how teachers and departments react on results obtained from student evaluation is discussed here in detail as well as the form in which the results should be presented. Emphasis is laid on the fact that student evaluation is only one of many methods for instructional quality evaluation and that it has not only its merits but drawbacks as well. A warning is given not to use rating scales in an unqualified manner and not to overestimate the results obtained especially for a summative evaluation.(ABSTRACT TRUNCATED AT 400 WORDS)
Attitude↗
[The effect of terguride on contractility of rat uterine strips].
The effects of terguride on the uterotonic activity of rat's uterine stria were investigated by means of a standardized isometric method of measuring in vitro the contractility of uterine muscles. The uterotonic activity of the given preparation depends on its concentration and on the phase of uterine cycle. The uterotonic activity makes 71.4 U.mg-1 in the range of terguride concentrations from 10(-7) to 10(-5) mg per ml. Used at higher concentrations, the uterotonic activity of terguride is very low. Spontaneous contractions are moderated and the tone of uterus is decreased by terguride administration.
Animals↗
[The effect of propranolol (Obsidan) as well as propranolol and fenoterol (Partusisten) on the motility of the smooth uterus musculature in vitro].
Propranolol (1; Obsidan) relaxes in vitro stripes of smooth muscles of non-pregnant rat's uterus in a concentration dependent manner. In contrast, on uterine muscle stripes of pregnant rats 1 causes small contractions. In an combination of 1 and fenoterol (2; Partusisten) (20:1) 1 prevents the relaxing effect of 2, reported to be an inhibitor of uterine muscle activity. This antagonism is most distinct on stripes of pregnant rat's uterus.
Animals↗
[Effect of the sequelae of acute hypobaric hypoxia on epileptic seizures in laboratory rats. Ontogenic studies].
Male rats of the Wistar strain were exposed at the age of 9, 14 and 18 days for a period of 30 minutes to hypobaric hypoxia corresponding to an altitude of 9,000 m. Twenty-four hours after exposure the right sensoric motor area of the cerebral cortex was repeatedly stimulated (rectangular pulses, 8 Hz, 20 s). Contrary to controls, the 10-day-old animals responded to this stimulation by an epileptic self-sustained after-discharge. In older animals the fits were shorter than in controls. Prolongation of the fits in conjunction with repeated stimulation was preserved. Contrary to controls, after the fourth stimulation the lengthening does not occur. In conjunction with older findings after chronic hypoxia, the authors discuss the possible affection of the monoaminergic mediator system.
Acute Disease↗
[Reconstruction of medical education in the USSR].
The submitted review is devoted to changes in undergraduate medical education in the USSR. In the first part the author discuss seven important problems faced so far by medical faculties: extensive approach to medical training, little effective organization and management of education, hitherto existing goals of undergraduate education, hitherto valid concepts of its contents, inadequate material conditions for training, declining quality of teachers and students. The mentioned problems still partly exist and make the efforts regarding reconstruction of education difficult. In the second part of the paper for each of the quoted problems changes are described which were already achieved or will be implemented in the near future. The author mentions also some controversial suggestions. Positive and negative experience with the reconstruction of the medical course are compared and weighted, incl. changes in the admission of students.
Education, Medical, Undergraduate↗
[The effect of partusisten, dilatol, papaverine and magnesium sulfate on uterine smooth muscle in vitro].
Inhibitory effects of Partusisten, Dilatol, Papaverin and Magnesium-sulfat on the activity of smooth muscle were tested in vitro on 18 isolated stripes of rats uteri, exhibiting both a high sensitivity against oxytocin and a distinct spontaneous activity. Minimal inhibitory concentrations of all drugs tested were determined, and their influence on the frequency and amplitude of contraction as well as on lag phase between inhibition and onset of spontaneous activity were registered. Basing on these experimental data conclusions were drawn concerning their clinical relevance.
Animals↗
[Amniotic fluid enzymes].
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Amniotic Fluid↗
Changes of the neuronal structure produced by prolonged hypobaric hypoxia in infant rats.
Structural parameters of neuronal circuits were studied in rats exposed to aerogenic hypoxia during the postnatal development. In 18-day-old experimental animals pyramidal cells of the hippocampal CA1 area had less branches of the apical dendrites. These branches were shorter with lower dendritic spine density. Myelinated axons in the corpus callosum were less frequent. In electron-microscopic picture the mean section area of myelinated axons was lower, the myelin sheets were thinner and consisted of less myelin layers. Synapses in the II. layer of the somatosensoric cortex had more often flat pre-synaptic dense projections, smaller width between pre- and post-synaptic densities and thinner post-synaptic densities.
Altitude↗
[The effect of calcium on the contractility of uterine strips in vitro].
Using a standard isometric method, the authors investigated the effect of some cations and nifedipine on the contractility of isolated strips of the human uterus in vitro. Evidence was provided that the contractility depends on the extracellular surface concentration of the calcium cation. Under the experimental set-up used intracellular calcium does not play any part and the contractions of the uterine strip depend on the state of the calcium channels.
Calcium↗
[The effect of certain drugs on the contractility of uterine strips in vitro].
The isometric method of assessment of the contractility of uterine strips in vitro makes it possible to follow up systematically the response of smooth uterine musculature to oxytocin and to test the effect of selected preparations on this process. In the submitted work the author investigated the effect of methyloxytocin, magnesium sulphate, seduxene, phenergan, plegomazine and DH-ergotoxin on the uterine contractions of strips of rat and human uteri ted. Based on the results of model experiments in vitro, the author discusses the effect of the mentioned substances on the spasmogenic activity of oxytocin.
Animals↗
Action of clonazepam and clorazepate on cortical self-sustained after-discharges in the rat.
Self-sustained after-discharges (SSADs) induced by electric stimulation of the sensorimotor cortex in rats exhibited under control conditions a significant progressive prolongation with repeated stimulations. Clonazepam not only blocked this increase in duration but it suppressed and/or abolished SSADs in a dose-dependent manner. Clorazepate in the lowest dose used (10 mg/kg) did not change SSADs. The two higher doses (25 and 50 mg/kg) blocked the prolongation of the 4th SSAD, i.e. this effect had a relatively long latency.
Animals↗