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PubMed1975

An animal model for the XXY Klinefelter's syndrome in man: tortoiseshell and calico male cats.

A review of the chromosome findings in 25 male tortoiseshell or calico (T-C) cats showed a variety of aneuploidy, polyploidy, mosaicism, and chimerism. An XXY-complement was included in the chromosome makeup of 16 of the 25 cats. Almost all of these cats were sterile. Testicular pathologic changes, when recorded, appeared comparable with that of human XXY Klinefelter's syndrome. The findings in 2 male T-C cats were presented as representative models of XXY Klinefelter's syndrome in man. Other findings in human Klinefelter's syndrome have not been looked for in the feline models, but a plan for this is underway. A review also was made of the historical steps leading to our present understanding of the Klinefelter syndrome including the role of Felis catus. An explanation of cat coat-color genetics clarified why "black" and sex-linked "orange" coloration can appear together normally in XX females and in rare males with 2 different X chromosomes. Thus, male T-C cats were only convenient indicators of underlying sex-chromosome aberrations which were occurring completely independent of coloration.

Aneuploidy↗
PubMed2001

Hypothalamic digoxin mediated model for oncogenesis.

This study assessed the changes in the isoprenoid pathway and its metabolites digoxin, dolichol and ubiquinone in neoplasms (CNS astrocytomas - glioblastoma multiforme and high grade non - Hodgkin's lymphoma). The following parameters were assessed-isoprenoid pathway metabolites, tyrosine and tryptophan catabolites, glycoconjugate metabolism, RBC membrane composition and free radical metabolism. There was an elevation in plasma HMG CoA reductase activity, serum digoxin and dolichol and a reduction in RBC membrane Na+-K+ ATPase activity, serum ubiquinone and magnesium levels. Serum tryptophan, serotonin, nicotine and quinolinic acid were elevated while tyrosine, dopamine, noradrenaline and morphine were decreased. The total serum glycosaminoglycans and glycosaminoglycan fractions (except dermatan sulphate in the case of CNS astrocytomas), the activity of GAG degrading enzymes and glycohydrolases, carbohydrate residues of glycoproteins and serum glycolipids were elevated. HDL cholesterol showed a significant decrease and free fatty acids & triglycerides were increased. The RBC membrane glycosaminoglycans, hexose and fucose residues of glycoproteins and phospholipids were reduced. The activity of all free radical scavenging enzymes, concentration of glutathione, iron binding capacity and ceruloplasmin decreased significantly while the concentration of malondialdehyde (MDA), hydroperoxides, conjugated dienes and NO increased. The concentration of alpha tocopherol was unaltered. Membrane Na+-K+ ATPase inhibition due to elevated digoxin, altered membrane structure and digoxin related tyrosine / tryptophan transport defect leading to increased levels of depolarising tryptophan catabolites and decreased levels of hyperpolarising tyrosine catabolites can lead to alteration in intracellular calcium/magnesium ratios and oncogene activation. Intracellular magnesium deficiency can produce defective microtubule related spindle fibre dysfunction and chromosomal non-dysjunction contributing to neoplastic cellular polyploidy and aneuploidy. Digoxin induced tryptophan/tyrosine transport defect can alter neurotransmitter patterns with increased serotonin, quinolinic acid, nicotine & glutamatergic transmission and reduced dopamine, morphine and noradrenaline levels leading to oncogenesis. Glycoconjugate metabolism is altered by elevated dolichol levels and magnesium depletion consequent to Na+-K+ ATPase inhibition. There is a qualitative alteration in proteoglycans and glycoproteins, defective membrane formation and structure and reduced lysosomal stability leading to disordered contact inhibition and tumour antigen presentation contributing to oncogenesis. Digoxin induced alteration in intracellular calcium/magnesium ratios and low ubiquinone levels can lead to a mitochondrial dysfunction resulting in increased free radical generation and reduced scavenging & caspase-3 activation producing a P21 defect contributing to oncogenesis.

Adult↗
PubMed2001

[Interferon-alpha directly inhibits thrombopoietin-induced megakaryocyte proliferation and differentiation].

OBJECTIVE: To characterize the inhibitory effect of interferon-alpha (IFN-alpha) on megakaryocyte proliferation and differentiation stimulated by thrombopoietin (Tpo). METHODS: Normal murine megakaryocytes were prepared by three different cell purification procedures. Megakaryocyte development was studied by semi-solid and suspension cultures and assessed with megakaryocyte colony forming unit (CFU-MK), acetylcholinesterase activity (AChE) as well as megakaryocyte count, diameter and DNA content. RESULTS: IFN-alpha prohibited CFU-MK formation and decreased AChE of megakaryocytes. The inhibitory effects were positively related to doses of IFN-alpha and could not be overcome by escalating exogenous Tpo or depriving accessory cells in bone marrow culture. IFN-alpha affected all aspects of megakaryocyte development, including decreases in megakaryocyte count, diameter and geometric mean polyploidy. CONCLUSION: IFN-alpha directly inhibits Tpo-induced megakaryocyte proliferation and differentiation in a dose-dependent manner.

Animals↗
PubMed2002

Ploidy levels and the number of nuclei in cardiomyocytes of the lamprey and fish.

It is well known that polyploidization of cardiomyocytes (CMC) is an essential component of heart growth in the warm-blooded vertebrates. Using the Feulgen cytophotometry of alkali-dissociated cells, we determined the ploidy in CMC of the lower vertebrates: lamprey Lampetra fluviatilis (Cyclostomata), skate Bathyraja maculata (Chondrostei), sterlet Acipenser ruthenus, and Russian sturgeon Acipenser güldenstädti (Ganoids), as well as paradise fish Macropodus opercularis, Amur sleeper Perccottus glehni, and Atlantic salmon Salmo solar (Teleostei). The data obtained have demonstrated a wide variety in CMC ploidy of both cyclostomata and fishes. About 85% of the lamprey CMC contain 2 or more (up to 17) nuclei per cell; with 90 and 10% of the nuclei being, respectively, diploid and tetraploid. Hearts of the skate and sturgeons contain mononucleated diploid CMC. In the perch-like fishes, mononucleated diploid and mononucleated tetraploid CMC make, respectively, 95 and 5%. The salmon heart contains near 50% of mononucleated diploid CMC, 13% of mononucleated tetra- and octaploid CMC, the rest CMC being multinucleated (up to 6 nuclei per cell). In all the examined species, the increased nuclear ploidy is accompanied with a significant increase in the nuclear volume. The number of nucleoli per nucleus does not correlate with the nuclear ploidy level. Evolutionary aspects of CMC polyploidy in chordates are discussed.

Animals↗
PubMedDate not supplied

Degradation of ATM-independent decatenation checkpoint function in human cells is secondary to inactivation of p53 and correlated with chromosomal destabilization.

DNA topoisomerase II is required in the cell cycle to decatenate intertwined daughter chromatids prior to mitosis. To study the mechanisms that cells use to accomplish timely chromatid decatenation, the activity of a catenation-responsive checkpoint was monitored in human skin fibroblasts with inherited or acquired defects in the DNA damage G2 checkpoint. G2 delay was quantified shortly after a brief incubation with ICRF-193, which blocks the ability of topoisomerase II to decatenate chromatids, or treatment with ionizing radiation (IR), which damages DNA. Both treatments induced G2 delay in normal human fibroblasts. Ataxia telangiectasia fibroblasts with defective G2 checkpoint response to IR displayed normal G2 delay after treatment with ICRF-193, demonstrating that ATM kinase was not required for signaling when chromatid decatenation was blocked. The G2 delay induced by ICRF-193 was reversed by caffeine, indicating that active checkpoint signaling was involved. ICRF-193-induced G2 delay also was independent of p53 function, being evident in cells expressing HPV16E6 to inactivate p53. However, as fibroblasts expressing HPV16E6 aged in culture, they lost the ability to delay entry to mitosis, both after DNA damage and when decatenation was blocked. This age-related loss of G2 delay in response to ICRF-193 and IR in E6-expressing cells was blocked by induction of telomerase. Expression of telomerase also prevented chromosomal destabilization in aging E6-expressing cells. These observations lead to a new model of genetic instability, in which attenuation of G2 decatenatory checkpoint function permits cells to enter mitosis with insufficiently decatenated chromatids, leading to aneuploidy and polyploidy.

Ataxia Telangiectasia Mutated Proteins↗
PubMed2002

[Relationship between expression of p27 and DNA ploidy in colorectal carcinoma].

BACKGROUND & OBJECTIVE: Cell cycle regulation changes in most of tumors. We can regard tumors as a kind of cell cycle diseases. p27 protein is a main negative cell cycle regulator, meantime it is an important prognosis factor of tumors. The significance of reduced expression and altered sbucelluar localization of p27 protein is unclear in progression of colorectal carcinoma. The relevance of p27 protein and DNA ploidy hasn't been reported in colorectal carcinoma. The study was designed to investigate the relationship between the expression of p27 protein and clinicopathological features, DNA ploidy in colorectal carcinoma. METHOD: The expression of p27 was observed in 40 colorectal cancer cases using immunohistochemical technique, and DNA content of cancer cells was analyzed using DNA imaging analysis system. RESULTS: The high p27 expression rate was 62.5% (25/40), while low expression rate was 37.5% (15/40). Low p27 expression was significantly associated with low tumor grade. (P < 0.05). In addition to nuclear staining, 32.5% (13/40) of the carcinoma displayed p27-positive immunoreactivity in cytoplasm. Cytoplasmic localization of p27 was association with late Dukes stage(P < 0.01) and high incidence of lymph node metastases(P < 0.05). The detective rate of polyploidy cell in the patients with p27 lower expression (22.2 +/- 11.3%) was significantly higher than that with p27 higher expression (8.0 +/- 7.7%, P < 0.001). CONCLUSION: Reduced expression and altered subcellular localization of p27 play a role in progression of colorectal carcinoma; one suppression tumor mechanism of p27 might be to prevent the acquisition of polyploid DNA content in colorectal carcinoma cells.

Adult↗
PubMedDate not supplied

[Chromosomal instability in rodents from the EURT territory: interspecies comparison].

The common vole (Microtus arvalis) and the mole vole (Ellobius talpinus) were trapped in the Eastern Urals Reserve (initial soil pollution 500-1000 Ci/km2) where many dozens of generations came to pass after the 1957 accident in the plant "Mayak" and in the Middle and South Urals and Transurals localities with global level of the 90Sr pollution. At present the average internal dose rate from 90Sr was 0.413 mGy/day in M. arvalis and 0.985 mGy/day in E. talpinus. The total accumulated doses from external and internal sources were 0.4-0.5 Gy per year. Frequencies of cell with chromosome aberrations and gaps and rates of aneuploidy and polyploidy were analyzed. In the common vole from EURT, the frequency of aberrant cells was significantly higher (4.57%) than in three control populations (0.44-0.86%). In the mole vole, all the cytogenetic parameters did not exceed the control ones. Absence of the genomic response in E. talpinus could be caused by the protective activity of melanin-related metabolites or by heritable factors, which may have arisen as a result of mutagenic pressure and have spread in the population in question both by selection and genetic drift, due to considerable isolation of local demes of E. talpinus.

Animals↗
PubMed2003

Adenoviral-mediated retinoblastoma 94 produces rapid telomere erosion, chromosomal crisis, and caspase-dependent apoptosis in bladder cancer and immortalized human urothelial cells but not in normal urothelial cells.

Retinoblastoma (RB)94, which lacks the NH(2)-terminal 112 amino acid residues of the full-length RB protein (RB110), is a more potent tumor and growth suppressor than RB110. In this study, Ad-RB94, but not Ad-RB110, produced marked growth inhibition, cytotoxicity, caspase-dependent apoptosis, and G(2)-M block in the human RB-negative, telomerase-positive bladder cancer cell line UM-UC14. This effect was completely inhibited by pretreatment with caspase inhibitors (P < 0.0001). Similar results were seen in RB-positive and other RB-negative bladder cancer cell lines. Ad-RB94 produced rapid telomere length shortening and loss of telomere signal, which was associated with polyploidy and chromosomal aberrations (P < 0.001). Ad-RB94, however, showed no cytotoxicity to telomerase-negative human normal urothelium cells but was highly cytotoxic to telomerase-positive human E6 and E7 immortalized urothelial cells (P < 0.0001). In addition, telomerase-negative cells, which maintain their telomere length through an alternative lengthening of telomeres DNA recombination pathway, showed no cytotoxicity to RB94. These results suggest that the induction of rapid telomere erosion and chromosomal crisis by RB94 in telomerase-positive cancer and in telomerase-expressing immortalized human cells is a major factor in its selective and potent tumor suppression and cytotoxic activity. The lack of cytotoxicity to normal cells should also provide a high therapeutic index when used in gene therapy protocols for the treatment of bladder and other cancers.

Adenoviridae↗
PubMed2003

Major transitions in evolution by genome fusions: from prokaryotes to eukaryotes, metazoans, bilaterians and vertebrates.

The major transitions in human evolution from prokaryotes to eukaryotes, from protozoans to metazoans, from the first animals to bilaterians and finally from a primitive chordate to vertebrates were all accompanied by increases in genome complexity. Rare fusion of divergent genomes rather than continuous single gene duplications could explain these jumps in evolution. The origin of eukaryotes was proposed to be due to a symbiosis of Archaea and Bacteria. Symbiosis is clearly seen as the source for mitochondria. A fundamental difference of higher eukaryotes is the cycle from haploidy to diploidy, a well-regulated genome duplication. Of course, self-fertilization exists, but the potential of sex increases with the difference of the haploid stages, such as the sperm and the egg. What should be the advantage of having two identical copies of a gene? Still, genes duplicate all the time and even genomes duplicate rather often. In plants, polyploidy is well recognized, but seems to be abundant in fungi and even in animals, too. However, hybridization, rather than autopolyploidy, seems to be the potential mechanism for creating something new. The problem with chimaeric, symbiotic or reticulate evolution events is that they blur phylogenetic lineages. Unrecognized paralogous genes or random loss of one of the paralogs in different lineages can lead to false conclusions. Horizontal genome transfer, genome fusion or hybridization might be only truly innovative combined with rare geological transitions such as change to an oxygen atmosphere, snowball Earth events or the Cambrian explosion, but correlates well with the major transitions in evolution.

Animals↗
PubMed1992

[A comparative morphometric and DNA content study of endometrial hyperplasia and adenocarcinoma].

The DNA content and morphometric study of four groups of endometrial proliferations were compared: adenomatous hyperplasia (21 cases), atypical hyperplasia (13 cases), adenocarcinomas with superficially myometrial invasion (9 cases) and with deep myometrial invasion (8 cases). The normal DNA histogram patterns were identified in the majority of the adenomatous hyperplasia. The important difference between proliferative and neoplastic endometrium was the size and shape of nuclei of epithelial cells. The DNA content and morphometric measurement of atypical hyperplasia and well-differentiated adenocarcinomas were similar. The highest proportions of cells with polyploidy were found in the deep invasive carcinomas. The study suggests the DNA content determination and morphometry are useful supplementary methods for observing the continuous pathologic process.

Adenocarcinoma↗
PubMed1992

The chromosome complement of human gametes.

The comparisons of observed and predicted rates of chromosomally abnormal gametes for two major classes of abnormality and for three specific trisomies are summarized in Table 2.10. As can be seen there is not very good agreement between the two sets of data. For sperm the observed abnormality rates are, with the exception of polyploidy, all in excess of those predicted. For structural abnormalities the excess is absurd and suggests that most structural abnormalities seen in sperm chromosomes may be preparation artefacts. On the other hand, it could be argued that the excess of hyperhaploidy among sperm is real and represents those trisomic conceptuses lost in the early stages of pregnancy. However, both chromosome 21 and the sex chromosomes are represented more often than any other chromosomes. Recent observations among all clinically recognized pregnancies do not suggest an excess of trisomy 21 conceptions arising from non-disjunction in spermatogenesis. As can be seen from Table 2.10, the observed frequencies of trisomy 21 is 10 times greater than that predicted, a difference that seems too great to be accounted for by early pregnancy wastage. While the X chromosome does appear to undergo non-disjunction much more frequently than the autosomes during spermatogenesis, the increase is restricted to non-disjunction of the XY bivalent at the first male meiotic division. In this class the observed and predicted frequencies are rather similar and it is even possible that the observed excess in sperm is accounted for by early post-zygotic loss. However, with the exception of the 24, XY class, the distribution of individual chromosomes among the hyperhaploid sperm bears little relation to that predicted. The most likely explanation for this is that banding of sperm chromosomes is of such poor quality that there are many errors in the identification of individual chromosomes. Most authors use some form of Q banding and this technique should give unequivocal identification of the highly-fluorescent Y chromosome even when other chromosomes are not clearly distinguishable. An increased accuracy of Y-chromosome identification may account for the relative concordance between observed and predicted rates of 24, XY sperm. By the same argument, 24, YY sperm might be expected to be accurately enumerated.(ABSTRACT TRUNCATED AT 400 WORDS)

Abortion, Spontaneous↗
PubMed1977

[Microspectrophotometric study of the content of various metabolites in cervical cancer].

The composite microspectrophotometric study of the content of DNA, PAS-positive, alcian-positive substances, lipids, and the activity of succinate dehydrogenase and ascorbic acid in the cervical epithelium normally and in cancer tumors showed preinvasive forms of cancer to be characterized by increased polyploidy, content of DNA and lipids, and increased activity of succinate dehydrogenase, and decreased content of glycogen, acid mucopolysaccharides and ascorbic acid. Invasive forms of cancer are characterized by more marked changes in these values.

Adult↗
PubMed2003

[Molecular cytogenetic characteristics of chromosome imbalance in cells of spontaneous human abortion fetuses with low proliferative activity in vitro].

Karyotyping of noncultivated cells of 60 first-trimester spontaneous abortions (blighted ova and missed abortions) was carried out using fluorescence in situ hybridization (FISH) with centromere-specific DNA probes for all chromosomes of the karyotype. Conventional cytogenetic study of these abortions was impossible because of cell culture failures. The algorithm is proposed for molecular cytogenetic FISH analysis of interphase karyotypes. Chromosome abnormalities were found in 32 fetuses (53.3%). In groups of missed abortions and blighted ova, the frequency of numerical chromosome abnormalities was 50 and 60%, respectively. Both the numerical chromosome abnormalities typical of spontaneous human abortions (autosomal trisomies, sex chromosome aneuploidy, and polyploidy) and a relatively rare type of genomic imbalance unidentifiable by standard cytogenetic analysis (autosomal monosomies 7, 15, 21, and 22 in mosaic state) were observed. The frequency of these type of chromosome abnormalities comprised 19% of all known karyotype abnormalities determined in spontaneously perished embryos. Note that the level of confined placental mosaicism in embryos with low cell proliferative activity was 25%, which is substantially higher than the corresponding parameter (1-2%) determined by prenatal diagnosis of chromosome abnormalities in developing embryos. The results of interphase FISH analysis of cells with low proliferative activity in vitro suggest that the pathology of early fetal development and missed abortion in humans are associated with a wider spectrum of chromosome abnormalities.

Abortion, Spontaneous↗
PubMed2002

Apomixis and cassava.

Apomixis means seed formation without fertilization. In cassava (Manihot esculenta) it is an alternative to reproduction by cuttings, which normally transmits pathogens and leads to an accumulation of viral and bacterial diseases. Apomixis also assures preservation of heterosis and avoids genetic segregation. It occurs in wild relatives of cassava and has been transferred successfully from Manihot glaziovii and M. neusana. It is facultative, and occurs at a low frequency, ranging from 1-2%, and apparently is genetically different from apomixis in other crops. With selection, the frequency can reach 13%. Apomixis in cassava is frequently associated with aneuploidy but it does occur in some diploid types. It is due to the formation of aposporic sacs, which can easily be detected by clearing tissue preparations. Apomixis appears to have played an important role in speciation during the evolution of Manihot, since it leads to the maintenance and perpetuation of sterile interspecific hybridization. The use of apomixis in cassava breeding could lead to a boom in line improvement and commercial production. In addition to preserving superior genotypes, avoiding contamination of new plants, it would enable international programs to export their germplasm to destination countries. This would allow the use of superior genotypes even if apomixis occurs at a low frequency. A scheme to maximize benefits is to use diploid apomictic clones as maternal parents, which can be crossed with pollinators of polyploid interspecific hybrids, followed by selection among the progeny of new apomictic types that combine the heteroses of both interspecific hybridization and polyploidy. In addition, they acquire favored genes that have been transferred from the wild to the commercial crop.

Cytogenetic Analysis↗
PubMed2004

[Mitotic catastrophe: a special case of apoptosis].

Mitotic catastrophe is a poorly defined type of cell death linked to the abnormal activation of cyclin B/Cdk1. Here we propose that a conflict in cell cycle progression or DNA damage can lead to mitotic catastrophe, provided that cell cycle checkpoints are inhibited, in particular the DNA structure checkpoints and the spindle assembly checkpoint. Two subtypes of mitotic catastrophe can be distinguished. First, mitotic catastrophe can kill the cell during or close to the metaphase, in a p53-independent fashion, as this occurs in Chk2-inhibited heterokarya generated by fusion. Second, mitotic catastrophe can occur after failed mitosis, during the activation of the polyploidy checkpoint, in a partially p53-dependent fashion. In these conditions, cells die as a result of caspase activation and mitochondrial membrane permeabilization that constitute hallmarks of apoptosis. Prevention of caspase activation and/or mitochondrial damage avoids mitotic catastrophe, indicating that this form of cell death indeed constitutes a special case of apoptosis. Importantly, the suppression of mitotic catastrophe can favor asymmetric division and the generation of aneuploid cells. This delineates a molecular pathway through which failure to arrest the cell cycle and inhibition of apoptosis can favor the occurrence of cytogenetic abnormalities which are likely to participate in oncogenesis.

Animals↗
PubMed2004

In vitro biological characteristics of human cord blood-derived megakaryocytes.

INTRODUCTION: Umbilical cord blood (CB) has been used as an alternative source for haematopoietic stem cell transplantation (HSCT) in recent years. However, delayed platelet recovery is frequently associated with CB HSCT. Megakaryocytes (Mk) are the specialised precursors of platelets and they are among the rarest haemopoietic cell types. Despite the rapid expansion of our knowledge of megakaryopoiesis in recent years, many questions, such as the molecular regulatory mechanisms in Mk differentiation and maturation, platelet formation and release, remain unanswered in CB-derived megakaryopoiesis. Variations can be seen from the literature by individual investigators using different approaches for Mk-specific differentiation and maturation induction. The development of in vitro culture methods to obtain sufficient numbers of Mks from readily available haematopoietic stem cells is of value for both basic research and clinical applications. MATERIALS AND METHODS: The CD34+ cells from cord blood samples were cultured in serum-free medium with haematopoietic growth factors (GFs), such as IL-3, stem cell factor (SCF), and thrombopoietin (Tpo). The differentiation of Mk was monitored using Mk- and platelet-specific monoclonal antibodies and flow cytometric analysis. The morphology of the cultured cells was studied by both light and electronic microscopy (LM and EM). The involvement of the human Notch gene family members was studied by real time-polymerase chain reaction (RT-PCR). Maturation of the cultured Mks was studied using flow cytometric analysis for both platelet-specific surface markers and enodomitosis. Platelet activation was assessed in the cytoplasmic fragments harvested from the cultures. RESULTS: Specific Mk differentiation of >70% resulted from a 2-step culture approach using IL-3, SCF and Tpo for 7 days followed by Tpo only for another 14 days. RT-PCR showed high-level expression of both Notch-1 and its ligand, Jagged-1, in the cultured Mks. Limited levels of polyploidy (>4N, endomitosis, EnM) were observed in the cultured Mks. The results also showed that the cytoplasmic fragments from the cultures responded to platelet activation reagents, including ADP and collagen, marked by upregulation of platelet-specific activation markers, such as CD62P (P-selectin) and PAC-1 (gpalphaIIbbeta3). CONCLUSION: The methods used in this study are specific for differentiation of Mk from CB CD34+ cell, which can partially mature and produce functional platelets in vitro. This approach for human Mk differentiation could be further optimised and may be adapted on larger scales for clinical purposes.

Antibodies, Monoclonal↗
PubMed2004

[Enhancement of plantlet regenerative efficiency of watermelon in vitro].

The purpose of this study was to enhance shoot regenerative efficiency of watermelon by optimizing culture parameters. Cotyledons at 4-day seedlings were explanted and cultured on MS medium supplemented with different combinations of hormones. In "Yixuan" cultivar, the plantlet regenerative frequency and shoots produced by per explant was as low as 10% and 0.4 respectively at all combinations tested when distal parts of cotyledons were inoculated. Whereas, maximum regenerative frequency of 100 percentage and 10.3 shoots regenerated from per explant were observed on MS medium supplemented with 5 mg/L BA and 0.1 mg/L IAA using basal parts of cotyledons as explants. Likewise, in "Jingxinmuben" cultivar, the highest regenerative frequency of 100 percentage and 6.9 shoots regenerated from per explant were obtained when proximal parts of cotyledons were cultured on MS medium containing 2 mg/L BA and 0.5 mg/L IAA. In the present study, adventitious buds were initiated after only 4 d in culture and intact plantlets were obtained in 40 d culture. This will facilitate quicker gene transformation and polyploidy induction of watermelon in vitro.

Citrullus↗
PubMed2005

Comparative study of the hepatotoxic, genotoxic and carcinogenic effects of praziquantel distocide & the natural myrrh extract Mirazid on adult male albino rats.

Praziquantel (PZQ) is widely and effectively used in the control of bilharziasis which constitutes a major endemic health problem in Egypt. However, recent studies recommended that the drug must be re-evaluated because of its potential carcinogenicity and genotoxicity. Mirazid is a new natural anti-schistosomal drug formed of myrrh extract and considered to be a safe drug. This work was conducted to evaluate and compare hepatotoxic, genotoxic and carcinogenic effects of PZQ and Mirazid on adult male albino rats by assessment of serum levels of ALT, AST and bilirubin, histopathological study of the liver and cytogenetic study of bone marrow cells. 100 adult male albino rats were equally divided into 4 groups: (I): negative control, (II): control rats received distilled water, (III): received weekly single oral dose of PZQ (1500 mg/kg) for 6 weeks, (IV): received daily oral dose of Mirazid (500 mg/kg) for 6 weeks. At the end of the study 10 rats of each group were investigated by assessment of the levels of AST, ALT, & Bilirubin. After scarification, liver sections were examined by light microscopy. Another 10 rats of each group were submitted to cytogenetic examination. It was found that praziquantel induced a significant increase in the mean values of AST, ALT and bilirubin with areas of hyaline degeneration, fatty changes, dysplasia and necrosis in the liver sections. It also induced a significant increase in the incidence of chromosomal aberrations as polyploidy, fragment, deletion and ring chromosome as compared with control group. Mirazid induced a non significant increase in the mean values of AST, ALT and bilirubin, with a normal hepatic tissue, and a non significant increase in the incidence of chromosomal aberrations, as compared with the control group. On comparing both drugs, praziquantel induced a significant hepatotoxic, genotoxic and carcinogenic effects. It was concluded that, Praziquantel is considered to be a hepatotoxic, genotoxic and carcinogenic drug. On the other hand, Mirazid seemed to be a safe and promising antiparasitic drug, free from hepatotoxic, genotoxic and carcinogenic effects.

Animals↗