Biomedical subjects

V Mares

Publications and source records attributed to V Mares.

At least 19 recordsLinked to original sources

PubMed2005

Intranuclear microtubules are hallmarks of an unusual form of cell death in cisplatin-treated C6 glioma cells.

We describe an unusual form of non-accidental cell death marked by ectopic microtubules in the nucleus of a subpopulation of cisplatin-treated C6 glioma astrocytes in culture. At electron microscopy, the perinuclear condensed chromatin did not completely adhere to the nuclear envelope of these cells being separated by single or loosely bundled 20-nm-thick microtubules located in an electron-lucid slit-like zone; the presence of alpha-tubulin lining the inner membrane of the nuclear envelope was confirmed by immunolabeling at confocal microscopy. Since tufts of microfilaments-like fibers also occurred in their central nuclear areas, these cells are referred to as CIMMs (Cells with Intranuclear Microtubules and Microfilaments). The nuclear reorganization of CIMMs also involved nucleolar segregation and formation of heterogeneous ectopic ribonucleoprotein (RNP)-derived structures, indicating disruption of the RNP-based transcription machinery. The cytoplasmic organelles of CIMMs were structurally intact, and propidium iodide did not accumulate intracellularly under vital conditions while the plasma membrane was often Annexin V-positive. All these findings suggest that CIMMs were lethally damaged and committed to an atypical programmed cell death resembling early apoptosis (this is also supported by the presence of a limited number of TUNEL-positive CIMMs). CIMMs appeared well before the main cisplatin-induced cycling arrest of the cell population (G2/M block at 72 h) and had mostly G1 DNA content: this suggests that they may represent the cohort of cells which passed cisplatin-altered mitoses with intranuclear retention of microtubules from an incompletely disassembled mitotic spindle.

Actin Cytoskeleton↗

PubMed2005

The influence of interleukin-1beta on gamma-glutamyl transpepidase activity in rat hippocampus.

Brain infections as well as peripheral challenges to the immune system lead to an increased production of interleukin-1beta (IL-1beta), a cytokine involved in leukocyte-mediated breakdown of the blood-brain barrier. The effects of IL-1beta have been reported to depend on whether the route of administration is systemic or intracerebral. Using 50-day-old male rats, we compared the effects of IL-1beta on brain gamma-glutamyl transpeptidase (GGT; an enzymatic marker of brain capillary endothelium) at 2, 24 and 96 h after either an intravenous (i.v.) injection of 5 microg IL-1beta or an intracerebroventricular (i.c.v. - lateral ventricle) infusion of 50 ng IL-1beta. When the i.v. route was used, the GGT activity underwent small but significant changes; decreasing in the hippocampus 2 h after the i.v. injection, increasing 24 h later and returning to control levels at 96 h. No significant changes in the hippocampal GGT activity were observed at 2 and 24 h following the i.c.v. infusion. The GGT activity in the hypothalamus remained unchanged regardless of the route of IL-1beta administrations. Similar changes in GGT activity were revealed histochemically. The labeling was found mainly in the capillary bed, the changes being most evident in the hippocampal stratum radiatum and stratum lacunosum-moleculare. A transient increase in GGT activity at 24 h, together with a less sharp delineation of GGT-stained vessels, may reflect IL-1beta induced increased turnover of glutathione and/or oxidative stress, that may in turn, be related to altered permeability of the blood-brain barrier in some neurological and mental disorders, including schizophrenia.

Animals↗

PubMed2005

Up-regulation of gamma-glutamyl transpeptidase (GGT) activity in growth perturbed C6 astrocytes.

Activity of gamma-glutamyl transpeptidase (GGT) was studied in astrocyte-like C6 glial cells modulated in growth and maturation by different concentration of serum and dibutyryl cyclic AMP (Db-cAMP) supplement in culture medium. After reduction of serum concentration from 10% to 0.1%, the number of GGT positive cells determined histochemically increased 3.1 times and the GGT activity/mg protein in whole cell lysates was 5.1 times higher. In cultures with 0.1% serum + Db-cAMP, the histochemically and biochemically assayed GGT activity exceeded 5.1 and 7.9 times the values measured in control 10% serum cultures, respectively. The up-regulation of GGT was accompanied by an inhibition of proliferation, enhanced differentiation and hypertrophy of cells. In addition, the process of metabolic perturbation and/or cellular stress was revealed in these cultures by the (i) growth-support release followed by shrinkage and death of a small number of cells and (ii) higher oxidation of 2'7'dichlorofluorescein diacetate to its fluorescent form in the adherent/viable cells. The observed up-regulation of GGT is considered to primarily reflect increased metabolism of glutathione and/or the maintenance of the redox potential in cells stressed by sub-optimal concentration of serum and Db-cAMP supplement. The concomitant cellular hypertrophy and differentiation and their relationship to increased activity of GGT await further investigation. The study suggests that up-regulation of GGT can contribute to adaptation of astrocytic cells to metabolic and/or oxidative perturbances occurring under various pathological conditions, including radiation- and drug-induced toxicity.

Animals↗

PubMed2004

Averaged particle dose conversion coefficients in air crew dosimetry.

The MCNPX Monte Carlo code was used to calculate energy-dependent fluence-to-effective dose conversion coefficients for neutrons, protons, electrons, photons, charged pions and muons. The FLUKA Monte Carlo code was used to calculate the spectral particle fluences of secondary cosmic rays for different altitudes, and for different combinations of solar modulation and vertical cut-off rigidity parameters. The energy-averaged fluence-to-dose conversion coefficients were obtained by folding the particle fluence spectra with the conversion coefficients for effective dose and ambient dose equivalent. They show a slight dependence on altitude, solar activity and location in the geomagnetic field.

Aircraft↗

PubMed2004

Options for the modified radiation weighting factor of neutrons.

The recent ICRP Report 92 has noted that the current radiation weighting factor, wR, depends on the energy of the incident neutrons in a manner that differs substantially from the dependence, which results from the current convention, QL. At all neutron energies, but most conspicuously below 1 MeV, the values of wR exceed those of the effective quality factor, qE. The discrepancy is largely due to the fact that--in the absence of computed values of the effective quality factor for neutrons--wR has been patterned after the values of the ambient quality factor, which accounts insufficiently for the low-linear energy transfer (LET) gamma ray component from neutron capture in the human body. There are different options to remove the discrepancy. Option 1 is to reduce wR substantially at all neutron energies to make it equal to qE for a standard condition, such as isotropic incidence of the neutrons. Since such a reduction may cause problems in those countries where the current wR values are already legally implemented, ICRP 92 has proposed what is here termed Option 2. It recommended to replace QL by the increased value 1.6 QL - 0.6 and, accordingly, to make the radiation weighting factor equal to 1.6 qE - 0.6. With Option 2 the radiation weighting factor needs to be decreased appreciably at low neutron energies, but for fission neutron spectra the overall changes are minor. To guide--regardless which option is chosen--the selection of the numerical values, the effective quality factor, qE, is computed here for different directional distributions of neutrons incident on the anthropomorphic phantoms ADAM and EVA. None of the sex averaged numerical values is found to deviate much from those for isotropic incidence. Isotropic incidence can, thus, be used as an adequate standard condition. A numerical approximation is proposed for the standard qE that is nearly equivalent to a formula invoked by ICRP 92, but is somewhat simpler and provides realistic values of qE even for the extremely high neutron energies in space. In line with ICRP 92, it is emphasised that wR needs to be seen as a derived quantity related to the LET-dependent weighting factor.

Dose-Response Relationship, Radiation↗

PubMed2004

[Neutron capture therapy in the treatment of glioblastoma multiforme. Initial experience in the Czech Republic].

BACKGROUND: Glioblastoma multiforme is the most frequent primary brain tumor in adults. Despite advances in surgery, radiotherapy and chemotherapy, its treatment remains unsatisfactory with very limited overall survival. In the year 2001, in cooperation with Department of Neurosurgery, Nemocnice Na Homolce and Nuclear Research Institute in Rez, we have started to treat glioblastoma patients with boron neutron capture therapy (BNCT). METHODS AND RESULTS: Cells of malignant brain tumors, especially that of glioblastomas, are able to accumulate boron compounds. If BNCT should be successful, it is necessary to reach selective accumulation of sufficient amount of 10B in the tumor and low accumulation in the normal brain tissue. After BSH administration, radiation with low energy thermal neutrons is delivered. It results in nuclear capture and fission reactions with subsequent selective damage of tumor cells. At the time of analysis 9 patients have been enrolled. Therapy was completed in 5 patients. Treatment has been very well tolerated. We observed minimal acute toxicity associated with radiation and no laboratory abnormalities after administrations of BSH. Unfortunately treatment results were quite unsatisfactory. The median time to progression and overall survival were shorter then expected with conventional treatment. CONCLUSIONS: BNCT is very well tolerated with only a modest toxicity. In contrast to standard radiation, BNCT patients receive only one dose of radiation. Nevertheless, in this small pilot study first results were inferior when compared either to outcomes of conventional therapy or to results reported from other BNCT groups. It might be explained that lower dose of radiation had been used. Further study will show whether the higher dose radiation can improve treatment results.

Adult↗

PubMed2003

Cisplatin induced gamma-glutamyltransferase up-regulation, hypertrophy and differentiation in astrocytic glioma cells in culture.

Gamma-glutamyltransferase (GGT) hydrolyses gamma-glutamylated peptides, including glutathione and transports amino acids into the cells. The enzyme is up-regulated in some tumors, especially those with a higher degree of malignancy and resistance to cytostatics. In this study we examined the effects of Cisplatin (1.6 x 10(-5)M) on the activity of GGT in astrocytic C6 glioma cells in cultures monitored for growth, morphology and differentiation. Initially (24 h), the drug inhibited cell division and later (96 h), it caused apoptotic death of about half of the population. The more resistant and surviving cells became hypertrophic and more differentiated, as indicated by their larger size and higher protein content, including the maturation- specific GFAP. In addition, the activity of GGT was significantly elevated in these cells at 48 h and onwards. At 96 h, the biochemically determined enzyme activity was between 230% and 330% above the controls. Compared to the protein content, the GGT activity started to increase later (48 h) but it grew steeper towards 72-96 h. Similarly, histochemical analysis revealed a manifold increase in the number of GGT+ cells in the population and higher intensity of staining per cell from at 48 h and onwards. The study showed that the transformed astrocytic cells can up-regulate GGT activity as part of an adaptation and/or, survival-enhancing reaction triggered by Cisplatin.

Antineoplastic Agents↗

PubMed2003

Subcellular targets of mercaptoborate (BSH), a carrier of 10B for neutron capture therapy (BNCT) of brain tumors.

The transformed C6 glial cells in cultures were treated with sodium mercaptoborate (Na(2)B(12)H(11)SH, BSH), a carrier of atomic targets ((10)B) of thermal neutrons for the neutron capture therapy of brain tumors. As shown by light microscopy, the therapeutic dose of BSH (100 microg/ml) did not alter the gross morphology and growth of the population of cells within a 72 h treatment interval. Electron microscopic analysis of these cells revealed activation of nucleoli and, occasionally, enlarged and bifurcated mitochondria. After 200 microg BSH/ml and 72 h treatment, growth of the cell population was inhibited and ultrastructural changes became more profound. They included condensation of chromatin and its allocation to the nuclear envelope which formed deeper invaginations. Mitochondria further increased in size and were characterized by slim or angular cristae. Moreover, in circumscribed segments of some of the slightly swollen mitochondria their cristae disappeared or were reduced to fine pouch-like structures localized near the continuous outer membrane, suggestive for a non-destructive restructuring of the inner mitochondrial membrane. The smooth pinocytotic vesicles near the plasma membrane, lysosomes and heterogeneous dense bodies were more frequent. The revealed subcellular targets of BSH may initiate the development of pharmacological protocols aimed to further improve the tolerance to BSH by the healthy tissues of patients undergoing BNCT of brain tumors, e.g. by intervention into the oxidative stress triggered likely by the altered mitochondria.

Animals↗

PubMed2001

Expression of attractin and its differential enzyme activity in glioma cells.

Attractin/mahogany protein was previously shown to be involved in a number of physiological and pathological events, including immune system regulation, body weight control, pigmentation, myelinization, and tumor susceptibility. Human attractin has an enzymatic activity resembling dipeptidyl peptidase IV (DPP-IV). In the central nervous system, attractin has been detected in neurons but not in glial cells up to now. We show the expression of attractin mRNA and protein in glioma cell lines at different degree of transformation. In human U373 and U87 glioma cells (Grades III and IV), membrane-bound attractin displays hydrolytic activity amounting to 5 and 25% of total cellular DPP-IV-like enzyme activity, respectively. Such activity has not been observed in the rat C6 glioma cells (Grade I). Attractin presence in glioma, but not in normal glial cells, together with its differential enzymatic activity, suggests its role in growth properties of tumors of glial cell origin.

Animals↗

PubMed2001

Fucosylated glycans in the periventricular structures and the cerebrospinal fluid of the fetal rat forebrain. An autoradiographic and lectin binding histiotopic study.

Our autoradiographic 3H-fucose incorporation study of the brains of 20-day-old rat fetuses showed that the synthesis of fucosylated glycans is significantly higher in the ventricular germinative zone of the forebrain hemisphere than in the more superficial layers, including the cortical plate. Intense incorporation of 3H-fucose also occurred in the choroid plexus, both its epithelial and stromal component, in the primordial ependymal lining of the lateral ventricles, meninges and capillaries of the forebrain parenchyma. In the lateral ventricles, densely labeled microprecipitates of the cerebrospinal fluid (CSF) were occasionally observed. The histiotopic differences in 3H-fucose labeling were absent, or were much less expressed, in the autoradiograms prepared from unfixed cryostat sections containing mainly unincorporated isotope. This indicates that the blood-mediated supply of 3H-fucose to the studied brain compartments was essentially equal and our incorporation data reflect actual differences in the rate of fucosylation within the forebrain hemispheres. The cytochemical lectin-binding assay, carried out with Ulex europaeus and Lotus tetragonolobus agglutinins, showed that regions with a higher rate of 3H-fucose incorporation were also richer in fucose-bearing glycoconjugates. The study revealed that the periventricular regions and the CSF of fetal rat forebrain form a fucosylated glycan-enriched complex, which represents a new chemoarchitectonic feature that may be of importance for maintaining the germinative properties of the ventricular neuroepithelium and the growth of the hemispheric ventricles.

Animals↗

PubMed2001

A sex-related difference in the hypertrophic versus hyperplastic response of vascular smooth muscle cells to repeated passaging in culture.

Activation of growth of vascular smooth muscle cells (VSMC) in adults participates in pathogenesis of dysplastic diseases of the vascular system. In this study, we examined the impact of gender of rat donors on the degree of hyperplastic and hypertrophic responses of VSMC in cultures subjected to repeated passaging. The cells were derived from the outgrowth zone of explants of the thoracic aorta and were studied up to passage 45. Under these conditions, the cells undergo repeated growth stimulation by the serum growth factors mimicking some pathological situations in vivo. At lower passages (5-7), the cells from both sex donors did not differ significantly in their doubling time, maximum population density, protein content and ploidy. At higher passages (40-45), we found that the hyperplastic response, monitored by doubling time and BrdU-revealed DNA synthesis, was more intense in VSMC of male origin. In contrast, female-derived cells reacted by more prominent hypertrophic changes. The latter included a relatively higher increase in the volume and protein content of cells. As indicated by the DNA content histograms and chromosome numbers, these cells also showed a higher degree of passage-dependent polyploidization. In addition, the female-derived VSMC were found to be more effective in adhesion to the growth support evidenced by wider spreading and higher resistance of these cells to trypsin-mediated detachment as well as higher expression of some integrin and cytoskeletal molecules. These features could partly account for the slower proliferation and polyploidization of these cells. The results suggest that rat VSMC populations of male and female origin contain cells which are intrinsically different with respect to their capability of reacting to growth stimuli. The lower responsiveness of female-derived cells to growth stimuli may contribute to less frequent formation of hyperplastic vascular lesions in female organisms.

Actins↗

PubMed2001

Dipeptidyl peptidase IV in two human glioma cell lines.

There is growing evidence that dipeptidyl peptidase IV [DPP-IV, EC 3.4.14.5] takes part in the metabolism of biologically active peptides participating in the regulation of growth and transformation of glial cells. However, the knowledge on the DPP-IV expression in human glial and glioma cells is still very limited. In this study, using histochemical and biochemical techniques, the DPP-IV activity was demonstrated in two commercially available human glioma cell lines of different transformation degree, as represented by U373 astrocytoma (Grade III) and U87 glioblastoma multiforme (Grade IV) lines. Higher total activity of the enzyme, as well as its preferential localisation in the plasma membrane, was observed in U87 cells. Compared to U373 population, U87 cells were morphologically more pleiomorphic, they were cycling at lower rate and expressing less Glial Fibrillary Acidic Protein. The data revealed positive correlation between the degree of transformation of cells and activity of DPP-IV. Great difference in expression of this enzyme, together with the phenotypic differences of cells, makes these lines a suitable standard model for further studies of function of this enzyme in human glioma cells.

Cell Division↗

PubMed2000

Fluorine ion-implanted polystyrene improves growth and viability of vascular smooth muscle cells in culture.

Vascular smooth muscle cells derived from the rat aorta were cultured on unmodified or F(+) ion-implanted polystyrene (5 x 10(12) or 5 x 10(14) ions/cm(2), energy 150 keV). In 1-day-old cultures, the cells adhered to the modified polystyrene in higher numbers and over larger contact areas. Increased resistance of the cells to trypsin-mediated detachment from the growth support indicated an improved adhesion of cells to the modified polymer at later culture intervals. The cells cultured on ion-modified polymers also were larger and had a higher total protein content. By use of immunocytochemistry, several specific protein species were increased, including the cytoskeletal alpha-actin and vimentin and the plasma membrane-associated vinculin, talin, alpha-v integrins, ICAM-1, and VCAM-1, which account for stronger cell-cell and cell-extracellular matrix adhesion. The lower number of cells found floating in the medium suggests that the spontaneous detachment of cells from the modified polystyrene was lower and that the viability of the adhered cell population was higher. As was shown by the two-parameter flow-cytometric measurements of BrdU incorporation and DNA content, as well as by (3)H-thymidine autoradiography, the cell proliferation on samples modified by the dose of 5 x 10(12) ions/cm(2) was similar to that in controls; and at the dose of 5 x 10(14) ions/cm(2), it tended to be even lower. The cells grown on the polymer implanted with the dose of 5 x 10(12) ions/cm(2) responded to a new artificially created cell-free area in a confluent cell layer by more intense migration whereas at the dose of 5 x 10(14) ions/cm(2), the migration ability of cells was similar to that on the unmodified polymer. The data revealed a higher biocompatibility of ion-implanted polystyrene with vascular smooth muscle cells in culture. There was better adhesion, differentiation, and survival, and there was neither excessive migration nor proliferation.

Animals↗

PubMed2000

Molecular mechanisms of improved adhesion and growth of an endothelial cell line cultured on polystyrene implanted with fluorine ions.

Endothelial cells derived from the bovine pulmonary artery (line CPAE, CCL 209, American Tissue Culture Collection, Rockville, MD, USA) were cultured on pristine or fluorine ion-irradiated polystyrene (5 x 10(12) or 5 x 10(14) F ions/cm2, 150 keV). At 24-h post-seeding interval, the number of cells which adhered to the ion-modified polystyrene was significantly higher than on the unmodified material (+20 and +58% in cultures with the polystyrene irradiated by lower and higher ion doses, respectively). On day 7, the populations cultured on the irradiated substrates grew to higher densities, exceeding the controls at the lower and higher ion doses by 69 and 180%, respectively. The cells on ion-implanted samples were also larger (+70-95% and +90-99% at the lower and higher ion doses, respectively) and contained more protein (+16% at both ion doses). As was shown by ELISA, the polystyrene irradiated by the higher ion dose enhanced the expression of a cytoskeletal protein, vimentin (+65%) and protein of focal adhesion plaques, talin (+15%). The content of integrin alpha5beta1 (VLA-5), receptor for fibronectin, was increased at both lower and higher ion doses (+22 and +57%). In contrast to this, the content of ICAM-1 and vinculin was similar in cells grown on both pristine and ion-irradiated growth substrates. Moreover, the expression of VCAM-1 and ELAM-1 was lower by 11-14% in both ion dose groups. The present study has shown that ion implantation of polymers improves the adhesion and growth of endothelial cells without elevating the expression of immunoglobulin and selectin types of adhesion molecules. This surface modification should promote colonization of an artificial vascular prosthesis by endothelial cells and make it less vulnerable by immune system cells of the recipient.

Animals↗

PubMed2000

Ultrastructure of nuclei of cisplatin-treated C6 glioma cells undergoing apoptosis.

C6 glioma cells, treated with a cytostatic dose of cisplatin (1.66 x 10(-5) M) ceased dividing by 24 h and, most of them had undergone apoptosis by 72-96 h. The reactive cells were classified into 5 types (T-I to V), according to the ultrastructure of nuclei. At 4 h, 20.4% of cells (T-I) showed minute condensation and margination of chromatin. The nuclear envelope (NE) formed slim and deep invaginations consisting of the inner or both membranes. The later kind of NE invaginations often extended to the enlarged nucleoli and contained nucleolus-like material at its cytoplasmic side. Some nuclear pores were covered with a dome-shaped "cap" formed by fine filamentous material. The number of T-I cells increased to 53.3% by 72 h. In T-II cells, which appeared at 24 h, the chromatin was condensed into dense irregular masses separated from the NE by a lucent space with filamentous structures preventing complete margination of chromatin. Nucleoli of T-II cells were small and showed partial segregation of their components. The "capped" pores were absent in these apparently more damaged cells. From 24 h, cells with large and lobulated nuclei (T-III) started to increase in number and peaked at 72 h (6.6%). Except for some small lobules, the chromatin of T-III cells was moderately aggregated and the NE was well preserved. Typical apoptotic cells with highly condensed and marginated chromatin (T-IV) peaked at 48-72 h (2.4-4.8%). They appeared in 2 varieties, including cells with wrinkled nuclei with less condensed and incompletely marginated chromatin or more lobulated forms with highly condensed marginated chromatin suggesting their origin from T-II or T-III cells. T-IV cells, as well as their fragments, underwent phagocytosis and secondary necrosis (T-V cells, 48.6% at 96 h). Two alternative routes of nuclear changes leading to cisplatin-triggered apoptosis, as represented by the sequence T-I --> T-III --> T-IV/V or T-I --> T-II --> T-IV/V, may explain the initially less or more damaged cells. These alternatives, together with progressive recruitment of reactive cells, suggest intrapopulation differences in the sensitivity of cells or in the cell cycle perturbations induced by cisplatin. Except for the T-IV and T-V cells, observed alterations of cytoplasmic organelles, including mitochondria, were fewer than reported in previous studies on cisplatin.

Animals↗

PubMed2000

[Nomenclature of drug forms--overview of development and the present state].

If the names used for dosage forms in pharmacopoeias and professional literature are examined, changes are found which are not always connected with extended knowledge about preparations, or the development of new variants of the dosage form. The same finding holds true for their classification into systematic groups. The problem has become particularly topical within the framework of international co-operation. The objective of the present paper is to inform about the steps aiming at standardisation of their nomenclature at least in Europe.

Czech Republic↗

PubMed1999

Hippocampal damage induced by carbon monoxide poisoning and spreading depression is alleviated by chronic treatment with brain derived polypeptides.

A model of acute carbon monoxide poisoning combined with spreading depression (SD) induced metabolic stress was used to examine the protective effects of cerebrolysin (CL) on the development of electrophysiological, behavioral and morphological signs of hypoxic damage. Capillary electrodes were implanted into the neocortex and hippocampus of anesthetized rats which were then exposed for 90 min to breathing of 0.8% to 0.5% CO, while 3 to 4 waves of cortical and hippocampal SD were elicited by microinjections of 5% KCl. Duration of SD-provoked depolarization of cerebral cortex and hippocampus was noted. Nine and 18 to 19 days later propagation of SD waves was recorded with the same electrodes and decrease of their amplitude was used as an index of brain damage which was significant in the hippocampus but not in the cortex. CL-treatment (2.5 ml/kg per day) started after CO administration and continued for 14 days significantly improved hippocampal recovery manifested by increased amplitude of SD waves. Behavioral tests performed 10 and 20 days after CO poisoning in the Morris water maze revealed better performance (escape latency 7 s) in the CL-treated than in untreated animals (14 s). Morphological analysis showed marked damage in the hippocampus consonant with electrophysiological and behavioral findings in the same animals. No apparent histological damage was found in rats exposed to CO inhalation alone without the additional SD-provoked depolarization. It is concluded that chronic CL-treatment enhances recovery of hippocampal tissue after hypoxic damage of intermediate severity.

Acute Disease↗

PubMed1999

Gender-related differences in adhesion, growth and differentiation of vascular smooth muscle cells are enhanced in serum-deprived cultures.

In 1-day cultures with 10% serum, the number of rat aortic smooth muscle cells (VSMC) adhering to the growth support was similar in cells from both sexes, whereas in 1% serum, the number of VSMC from male donors was lower. In 10% serum medium, the doubling time was significantly shorter and the number of [3H]thymidine-labelled nuclei was higher in cells of high passage from male rats. In serum-free medium, these differences increased and were also seen in cells of low passage number. Morphologically, the cells in male-derived cultures at higher passage number were mainly spindle-shaped, formed well-developed 'hills and valleys' and possessed longitudinally oriented bundles of alpha-actin-containing microfilaments. Most cells from female rats were flat, polygonal, the multilayered 'hills' were less prominent, with alpha-actin microfilaments forming a mesh-like network.

Animals↗