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The heat shock response, characterized by increased expression of heat shock proteins (Hsps) is induced byexposure of cells and tissues to extreme conditions that cause acute or chronic stress. Hsps function as molecularchaperones in regulating cellular homeostasis and promoting survival. If the stress is too severe, a signal that leadsto programmed cell death, apoptosis, is activated, thereby providing a finely tuned balance between survival anddeath. In addition to extracellular stimuli, several nonstressful conditions induce Hsps during normal cellulargrowth and development. The enhanced heat shock gene expression in response to various stimuli is regulated byheat shock transcription factors.

Dedicated to the 60th birthdays of prof. MUDr. Václav Lichnovský, DrSc.The neonatal rat cardiomyocyte model enables heart researchers to study and understand the morphological,biochemical and electrophysiological characteristics of the heart. This model offers a broad spectrum of experiments,such as studies of contraction, ischaemia, hypoxia and the toxicity of various compounds. This reviewexamines the methodology for the isolation and cultivation of primary neonatal rat cardiomyocyte cultures,considers possible problems and pitfalls, and presents an optimized protocol for cardiomyocyte preparation.

In vitro subcellular and cellular systems have important and irreplaceable roles in the metabolic investigationsthat precede the development of new potential drugs. Of these model systems, tissue slices are probably the nearestto in vivo conditions. From the experimental and complexity points of view, perfused organs lie midway betweentisssue slices and whole organism. Preparation and working with liver slices is quick and easy, and, excess materialcan be cryopreserved and stored untill the next experiment. Slices can be prepared from a wide variety of organsand it is possible to co-incubate them. Another important feature is the possibility of interspecies comparison ofslices. Different experiments can be run both in the short-term as well as long-term incubations. Each in vitro systemhas an important place for example, in the development of new medicaments. It is therefore important to compareand supplement experimental results from different in vitro systems when extrapolating to in vivo situations is done.

The effect of particle size on bioavailability of 9 different formulations with cyclosporine A was studied.A common feature of all the formulations was the ability to form submicron dispersions under dilution. Thecomposition of individual formulations was chosen in such a way that they were based on same or similar excipients.For each formulation, pharmacokinetic study was carried out in beagle dogs. On groups of 10 dogs, the averageAUC was evaluated. Particle size of formulations under dilution in water was measured by laser scattering method.According to the results of particle size measurement, the formulations were sorted out into groups of similarparticle size distribution by use of two methods of multivariate statistical analysis. The average AUC within groupsand between-groups was compared, and the effect of particle size on bioavailability was evaluated.

With an increasing number of lipophilic drugs under development, homolipids and heterolipids have gainedrenewed interests as excipients for oral drug delivery systems. Oral administration has many advantages for chronicdrug therapy. It is relatively safe, convenient for the patient and allows self administration.This article is notintended to review the broad area of lipid-based vehicle for oral drug delivery comprehensively. The rationalebehind choosing lipids materials for pharmaceutical dosage forms and their applications is discussed. It alsocomments on the methods for monitoring the physicochemical properties of vehicles and formulations anddescribes a range of pharmacopoeial excipients suitable for these purposes. The excipients selected here arepharmacopoeial in European Pharmacopoeia 4th Ed.,United States Pharmacopoeia 24th Ed./National Formulary19th Ed. and Japanese Pharmacopoeia 13th Ed. or are drafted in Pharmaeuropa and Pharmacopoeial Forum.Widening availability of lipidic excipients with specific characteristics offer flexibility of application with respectto improving the bioavailability of poorly water-soluble drugs and manipulating release profiles.

The authors present a review of up-to-date methods of vasoformative tissue tumours treatment. The necessity tochoose the best therapy and the risks of single therapeutical procedures are pointed out.

The study addressed the effect of colchicine and its derivatives on the protein levels of cytochrome P450 (CYP)1A2, 2A6, 3A4, 2C9/19, and 2E1 isoforms. Primary human hepatocyte culture was the model of choice. Levels ofindividual CYP isoforms were detected using immunoblotting. Colchicine caused an increase of CYP2E1 proteincontent, colchiceine and N-deacetylcolchiceine induced isoforms CYP2C9, 2E1 and 3A4 whereas colchicosideinduced CYP2C9 and 2E1. The levels of CYP1A2 and 2A6 were unaffected by any of tested compounds.Demecolcine and 3-demethylcolchicine had no effect on any studied P450 isoform. Since colchicine is an exclusivesubstrate of CYP3A4 whereas it induces CYP2E1, there is a suspicion rather at protein stabilization than at geneinduction concerning induction origin.

Olomouc, 7 June 2000

Heart rate variability reflects the activity of autonomic nervous system. The aim was to evaluate the value ofshort-term spectral analysis of heart rate for monitoring the effects of exercise training on the autonomic nervoussystem in subjects following myocardial infarction. Short-term spectral analysis of heart rate variability wasperformed during standardised supine-standing-supine test in a group of 29 clinically stable patients after myocardialinfarction and the same test was repeated after 2 months of exercise training (ergometry or rapid walking).Each subject exercised at 60–80% of his maximal performance for 30 minutes once a day. Short-term spectralanalysis of heart rate variability was assessed in the frequency range of 0.02–0.5Hz involving very low frequency(VLF, 0.02–0.05Hz), low frequency (LF, 0.05–0.15Hz) and high frequency (HF, 0.15–0.5Hz) spectral bands. Theinfluence of exercise training on the autonomic nervous system was registered in the physically active group (n = 16)as a decrease in sympathetic response to standardised orthostatic load. In conclusions the regular exerciseinfluenced an altered neural autonomic regulation of heart rate in post-infarction patients shown by a decrease insympathetic activity in the short-term heart rate variability. This method enables monitoring of the effects ofphysical training on the autonomic nervous system in patients following myocardial infarction.

The budding yeast Saccharomyces cerevisiae has long proved to be a very useful model in cell biology. Its cell morphologyis established and maintained at least in part by the cell wall, a rigid but dynamic structure that affords mechanical protection.Although fungal cell walls represent an unique phenomenon, recent progress in research has shown striking parallelsbetween yeast and mammalian cells in the area of cell morphogenesis and proliferation. Further studies promise to shedcommon light on the processes of cell morphogenesis including the intersections with proliferation control. This reviewfocuses on the recent progress in this promising area in the yeast Saccharomyces cerevisiae.The process of cell wall synthesis in Saccharomyces cerevisiae was reviewed by several authors recently1,2,3. Briefly, thecell wall represents a complex structure of cross-linked chitin, β-(1,6)-d-glucan, β-(1,3)-D-glucan and mannoproteins.Chitin and β-(1,3)-D-glucan are synthesized by enzymatic complexes at the cell membrane and extruded into the periplasmicspace, mannoproteins are synthesized along the yeast secretory pathway, and the site of β-(1,6)-D-glucan synthesis is stillunknown. The principal motif which interconnects individual cell wall constituents was recently identified by Kollár4 etal. The mechanisms of cross-linking of the polymers in the wall remain unknown, however. Recently, nevertheless,substantial progress has been achieved in understanding the signalling pathways which target the cell wall construction.

Leptin receptors are supposed to have signal effects and are located in most tissues in the organism but we failedto find literary data on concentration (measurement) of leptin receptors in the system circulation. We examined bythe method of randomized selection the group of 20 patients with manifested atherosclerosis in whom BMI wascalculated. Then we analyzed concentration of leptin receptor (double sandwich ELISA, standard recombinanthuman leptin), leptin, glucose, insulin, proinsulin, CRP and uric acid in the serum. The control group consisted of103 probands without signs of atherosclerosis or other manifested diseases. The control group was subjected todetermination of BMI, leptin and leptin receptor in the serum. Concentration of leptin receptor does not differsignificantly between the patients with atherosclerosis and normal population. Probands with atherosclerosisshowed a very close negative correlation between concentration of leptin receptor and leptinemia which is absent innormal population.

Dedicated to the memory of doc. MUDr. et RNDr. Milan Černý, CSc. The changes appearing during the development of the human palatine tonsil, both in the surface and in thetonsillar crypt epithelium, were studied from samples of the 16th to 40th prenatal weeks. From the 18th week, weobserved areas of mesh-like epithelium in an originally homogeneous stratified squamous epithelium, i.e. thereticularisation began in the tonsillar crypt epithelium. The important role of the epithelial basal membrane in thisprocess is discussed. The diffuse spongy-form type of reticularisation as well as the formation of the intraepithelialpassages between the epithelial columns are described. The lymphoid cells and macrophages migrated throughthese microcrypts and they were frequently seen near the crypt epithelial micropores on the surface of thereticularised epithelium.

The article refers to the technique of biomagnetical separation (BS) of mRNA using “DynabeadsR mRNADIRECT”. After a brief survey of RNA isolation methods authors describe a general procedure of BS as well as itsconcrete application for mRNA isolation from bronchoalveolar cells. Authors report results of specific experimentsto assess the efficiency and accuracy of mRNA isolation by BS. The applicability of BS technique for the geneexpression studies is discussed in the end of the article.

Promoting effect of cyclic monoterpenes on percutaneous absorption of antiarrhytmic drugs disopyramide, lidocaine andtrimecaine was investigated in the rats. Laurocapram (Azone) was used as a standard comparator of penetration enhancement.The absorption of trimecaine was significantly enhanced by addition of limonene, trans-p-menthane and Azone in1% concentration. Lidocaine and disopyramide penetrated across the skin only when 1% of limonene was used. Othercyclic monoterpenes showed no effect on percutaneous absorption of examined drugs.

Sixty spleens were observed according to the size of the splenic hilus depending on the size of the human spleen. Thediameter and area of the lumina of the arterial branches were measured in 30 casts of the vascular bed of the spleen.Results were statistically evaluated, tabelated and graphed.

The authors observed in 60 human spleens the course of the splenic artery in the splenic hilus and branching of segmentalbranches in the spleen. Specimens of blood vessels and casts showed two extreme types of segmental branches enteringthe splenic parenchyma: 1. Vertical type and 2. subcapsular type. The authors also studied the occurence of anastomosesberween the individual branches of the splenic artery and recognized three types of them: 1. hilar – extraparenchymatous,2. intraparenchymatous and 3. subcapsular.