Effect of human leukocyte interferon on human lymphocytes in vitro: cytogenetic studies

Mitogen-stimulated lymphocytes from 8 healthy donors were exposed to interferon, and cytogenetic studies were preformed. The response of lymphocytes to the mitogens phytohemagglutinin (PHA), concanavalin A (con A) and pokeweed mitogen (PWM) was inhibited by interferon, whereas an increased number of structural chromosomal aberrations was not detected. Further investigations of the cytogenetic effects of interferon are needed.     

A cytogenetic study on human intestinal trematodes of the genus Metagonimus (Digenea: Heterophyidae) in Korea

In order to analyze chromosome numbers and karyotypes of intestinal trematodes belonging to the genus, Metagonimus, the gonad tissues of M. takahashii, M. miyatai, and M. yokogawai were prepared and examined. The number of bivalents in the first meiotic division of M. takahashii was nine (n = 9). The diploid number of M. miyatai was observed to be eighteen (2n = 18) and their chromosomes consisted of one pair of metacentric, 7 pairs of submetacentric, and one pair of telocentric chromosomes. The diploid number of M. yokogawai was thirty-two (2n = 32) and the chromosome complements were composed of two pairs of metacentric, 11 pairs of submetacentric, and three pairs of subtelocentric chromosomes. These results could be a supporting evidence for the validity of the new species, M. miyatai, distinct from M. yokogawai.     

Effect of infectious factors on human and animal cytogenetic structures]

The analysis of blood leucocyte chromosomes has been carried out on 60 patients with different infectious diseases (influenza, measles, scarlet fever, and disentery), and on 47 patients immunized against measles, tick-born encephalitis, typhoid fever and brucellosis. The mutagenic influence of viruses on the genital cells of mice and on the human somatic cells in vitro was studied. Both viruses and bacteria appeared to be able to bring about different breaks in human and animal cells.     

Oxygen-induced cytogenetic instability in normal human lymphocytes

Summary Chromosomal aberrations were scored in normal human lymphocytes cultured for 3 to 7 days at 20, 40, 50, and 60% oxygen. Compared to normoxic cultures (20% O₂), in hyperoxic cultures (40% to 60% O₂) the frequency of aberrant cells was significantly increased, especially at the longer incubation times. The increase was mainly due to chromatid-type damage: chromatid gaps, breaks, and interchanges. In addition, long-term hyperoxic cultures had a remarkably high incidence of endoreduplications, up to 7.4%. It appears that prolonged hyperoxic incubation induces a pattern of cytogenetic abnormalities in normal human lymphocytes similar to that present spontaneously in 3-day normoxic cultures from patients with Fanconi anemia.     

In vitro cytogenetic studies of cypermethrin on human lymphocytes

Assessment of cytotoxicity and response to external factors like pesticides were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide (MTT) or MTT assay, which measures mitochondrial metabolism in the entire cell culture and provides information about the percentage of cell survival. Utilizing the MTT assay, the cytotoxicity of cypermethrin was determined on lymphocyte cultures from human peripheral blood samples, the short-term lymphocyte cultures were incubated with various aliquots of the cypermethrin and the LC50 was found to be 33.6 microM. Lymphocytes treated with low-doses (1/10 of LC50) of cypermethrin showed an increase in the frequency of chromosomal aberrations and found to be significant. Karyotype analysis revealed more satellite associations and chromosomal breaks in cypermethrin treated samples. Low-doses of the pesticide also induced single-strand breaks in the DNA as assessed by comet assay. The pesticide caused increase in the comet tail length with increase in pesticide concentration, implicating genotoxicity in somatic cells. It is concluded that In vitro assays could give important information of the mechanism of toxicity at low dosages and impact on genetic material of human origin.     

Evaluation of cytogenetic effects of lambda-cyhalothrin on human lymphocytes

The genotoxic and cytotoxic potential of lambda-cyhalothrin (LCT), a synthetic pyrethroid insecticide, was investigated on human lymphocytes cultured in vitro. Utilizing the trypan blue dye exclusion technique assay, the LC50 of LCT was found to be 28 microM. Based on the LC50 value, it is seen that LCT was highly toxic to lymphocyte cultures, among other pyrethroid group of pesticides. Chromosomal aberrations induced by LCT were determined using metaphase plate-spreads of lymphocytes. The chromosomal analysis was recorded using Medi-Image software technology. The analysis revealed that more satellite associations and gaps were found, which were statistically significant (p < 0.05) when compared to controls. Comet assay was used to assess the possibility of LCT to induce the damage in DNA, where the increase in comet tail length relates to the extent of DNA single strand breaks. The results presented here indicate that in vitro assays could be used as indicators of cytotoxicity and genotoxicity of the pesticide.     

Comparative in vitro cytogenetic studies in mercury-exposed human lymphocytes

As part of a long-term cytogenetic research project on mercury, we studied the in vitro clastogenic capacity of HgCl2 and CH3HgCl as well as their influence on chromosome segregation by means of a computer-aided chromosome distribution study in metaphase plates. As in other in vitro studies published elsewhere, we exposed human peripheral blood lymphocytes to different concentrations of the mercury compound during a limited period of the pre-DNA synthetic stage (G1-S) or from that stage up to mitosis (G1-M). For both exposure periods and both mercury compounds we observed a rather important clastogenic effect as well as a dissociation of the (normally highly associated) acrocentrics. The results do indicate, in conjunction with previously published data, that mercury compounds alter the chromosome segregation at lower concentrations than those observed for clastogenicity. Moreover, the effects on chromosome segregation are not necessarily due to binding to spindle proteins. Binding to--and inactivation of RNA polymerase I may for example be another mechanism of action which is more important for the inorganic form of mercury than for the organic form.     

Studies on tissue cultures of the genus Cinchona L. alkaloid production in cell suspension cultures

Initiation and culture of callus and cell suspensions of Cinchona ledgeriana and C. succirubra as well as the successful isolation and selection of a high-yielding alkaloid-forming strain derived from the leaf rachis of a C. succirubra plant are described. Results of feeding experiments with L-tryptophan using two different culture procedures are presented and discussed. Maximum alkaloid yields of up to 0.9% (based on dry weight) or 6.35 mg/l have been obtained.     

Dose curves for radiation-induced cytogenetic damage in human lymphocytes

Insufficient fitness of experimental data with convenient linear and linear-quadratic models of "dose-effect" dependence for the number of chromosome aberrations of different types were revealed. Proposed method of approximation of the experimental "dose-effect" dependence with piece-linear splines allows to obtain more accurate results in the most cases and therefore is more preferable than the linear and linear-quadratic models.     

Distribution of the genus Mallomonas (Synurophyceae) - ubiquitous dispersal in microorganisms evaluated

The neutral dispersal model in protists was suggested as a general principle resulting in either cosmopolitan or ecologically restricted distribution of individual species. The high local diversity results in "flat" species-area curves of individual protist groups. We investigated the local and regional diversity of the genus Mallomonas in the alluvial plain of upper Luznice in the Czech Republic. About 86.5% of species previously reported from all types of freshwater biotopes within the country were found in our investigated localities. However, there was a considerable increase of species numbers in relation to the total area of available habitats on the continent and global scales. In three species found in our localities, the floristic data indicate a possible geographically restricted distributional pattern. Here, we discuss possible reasons for this phenomenon.     

Effect of vasoactive intestinal polypeptide (VIP) on growth hormone (GH) and prolactin (PRL) release and cell morphology in human pituitary adenoma cell cultures

Six GH adenomas and three prolactinomas were investigated by light- and electron-microscopic morphological and immunocytochemical methods and the effect of vasoactive intestinal polypeptide (VIP) on growth hormone (GH) and prolactin (PRL) secretion was tested in vitro. The tumour cells of the acromegalic patients revealed both GH and PRL immunoreactivity while prolactinomas showed only PRL activity. All the adenomas stained immunocytochemically also for VIP. By electron microscopy, the tumours included two densely and two sparsely granulated GH, two mixed GH/PRL, and three sparsely granulated PRL adenomas. The dissociated cells were explanted, and cultured in vitro. The cultures in micro test plates were treated with VIP at different concentrations between 10(-5)-10(-12) M. GH and PRL contents in the culture media were measured by radioimmunoassay. GH release was significantly stimulated by VIP in a dose-dependent manner over the whole concentration range, while VIP was effective on the PRL release only at 10(-6)-10(-7) M concentration. The cells of a mixed adenoma were grown in Petri dishes and used for ultrastructural and immunocytochemical studies. The cytoplasmic structure of the cells treated with VIP corresponded to that of active hormone-secreting cells with large ergastoplasmic fields and Golgi zones containing secretory granules. Massive exocytotic events were encountered mainly in the GH-type cells. GH and PRL double immunocytochemistry showed the predominance of GH cells, many of them containing low amounts of PRL as well. Cells predominantly containing PRL were spread among them, they also might contain GH as well. Some of the cells contained only a single immunoreactive hormone. The intensity of gold labelling of the secretory granules appeared higher in the VIP-treated cells than in the untreated control ones which showed a cytoplasmic structure characteristic of glandular cells with low secretory activity. As all the adenoma cells both contained and reacted to VIP, our results are in agreement with an autocrine or paracrine effect of this peptide. The fine structure of the cells in the cultures treated with VIP supply an additional argument to the assumption that VIP may serve as a growth factor for these cell types.     

Effect of interferon on the number of cytogenetic disorders occurring in human cultured lymphocytes treated with thio-TEPA and fotrin

The paper deals with the modifying effects of natural (leukocytic) and synthesized (recombinant) interferons on the number of cytogenetic injuries in the cultured lymphocytes of human peripheric blood after exposure to alkylating chemicals--thio-TEPA and fotrin. The analysis of chromosomal aberration levels is suggestive of a significant protective effect exerted by interferons. The addition of the recombinant interferon increased the number of sister chromatid exchanged frequency in mutagen treated variants. The application of the test system that involves two types of interferon made it possible to reveal differences in their cytogenetic effect during the protector-sensitive period of cultivation.     

Comparative study on cytogenetic damage induced by homo-aza-steroidal esters in human lymphocytes

The effect of P[N,N-bis(2-chloroethyl)amino]phenylacetate esters of $\text{3β-}\text{hydroxy}\text{-}\text{methyl}\text{-17α-}\text{aza-}\text{d}\text{-}\text{homo}\text{-5α-}\text{androstan}\text{-17-}\text{one}$ (compound 3) and 3β-hydroxy-17α-aza-d-homo-5α-androstane (compound 2) on sister-chromatid exchange (SCE) frequencies and on human lymphocytes proliferation kinetics was studied. The results are compared with those of the P[N,N-bis(2-chloroethyl)phenylacetate esters of 3β-hydroxy-17α-aza-d-homo-5α-androstan-17-one (compound 1). All compounds were found to be active in inducing markedly increased SCE rates and cell division delays. A correlation between potency for SCE induction, effectiveness in cell division delay and previously established antitumour activity of these compounds was observed.     

Induction of cytogenetic damage by modified steroidal derivatives of p-bis(2-chloroethyl)aminophenylacetic acid in human lymphocytes

The effect of modified steroids, containing alkylating agents, on SCE rates and on cell kinetics in cultured human lymphocytes was studied. The homo-aza-steroidal ester of p-bis(2-chloroethyl)aminophenylacetic acid (ASE) was found to be the most effective in causing markedly increased SCE rates and cell division delays. The androsterone ester of p-bis(2-chloroethyl)aminophenylacetic acid (AE-CAPA) was found to be next in order of effectiveness with the lactone ester (LE-CAPA), chlorambucil ester 3 beta-hydroxy-13a-amino-13,17-seco-5a-androstan-17-oic-13,17-lactam (CBC-HAAL) and chlorambucil (CBC) following. p-Bis(2-chloroethyl)aminophenylacetic acid (CAPA) had only a small effect and 3 beta-hydroxy-13a-amino-13,17-seco-5a-androstan-17-oic-13,17-lactam (HAAL) had no effect at all. A correlation between potency for SCE induction, effectiveness in cell division delay and previously established antitumor activity of these drugs was observed.     

Immunologic typing of splenic lymphocytes from human fetuses--donors of pancreatic islet cell cultures

To determine the HLA-phenotype of a potential donor of pancreatic islet cells, use was made of lymphocytes from 18-25-week-old human fetuses. The HLA-phenotype was clearly established in 39 out of 52 cases. In 13 cases, the authors failed to reveal histocompatibility antigens because of low viability of lymphocytes. The relationship was ascertained between the detectability of HLA-antigens in fetal donors and cytophysiological characteristics of islet cell cultures prepared from the pancreas.     

Effect of passaging on Mer phenotype of human fetal cell cultures

With increasing passage in culture, the human fibroblast cell strain GM11 lost the Mer+ phenotype (the ability to support the growth of adenovirus 5 damaged prior to infection by MNNG). All of 46 embryonic strains prepared either from various organs of 20 fetuses from 6-7 to 13-14 weeks of gestational age or from two hydatidiform moles showed normal repair of MNNG-treated virus. We conclude that human fetal strains are not usually deficient in such repair, and that the behavior of GM11 is atypical.