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At least 145 records · Page 8Linked to original sources
PubMed1994

Histopathological analysis of mice born following single cell embryo biopsy.

Single cell embryo biopsy is a useful but invasive technique for preimplantation diagnosis. Biopsy may be performed by physical (direct zona puncture) or chemical methods (zona drilling with acid solution). This study has analysed the safety of a physical method of embryo biopsy in the mouse. Six adult mice (male and female), three from biopsied embryos and three from a control group (non-biopsied) were subjected to histopathological analyses. Macroscopically, the anatomy and morphology of the internal organs in both groups were normal. Microscopic analyses of 15 major organs, which included the brain, heart, lung, liver, kidney, stomach, intestine, voluntary muscle, spleen, pancreas, adrenal, thymus, skin, testis (male) and ovary (female), in both groups were all normal. These results showed that careful single cell embryo biopsy by direct zona puncture performed at the 8-cell embryo stage had no adverse influence on the macroscopic and microscopic structure of the organs. The remaining pluripotential cells of biopsied embryos developed normal microstructure according to the hereditary messages. Ideally, the safety of embryo biopsy requires observation of three stages after embryo biopsy, namely embryonic and fetal development before birth, neonatal assessment and long-term monitoring after birth.

Animals↗
PubMed2005

Extraction of pure cellular fluorescence by cell scanning in a single-cell microchip.

A 3-dimensional liquid flow control method has been developed to manipulate and retain a single yeast cell freely in a microchip. This method allows us to carry out single-cell experiments by selecting any desired single cell from a group, retaining the cell for cellular signal detection, and delivering reagents to the cell during continual detection and observation without any negative impact from the liquid flow on the live cell. The cell was scanned back and forth across an observation window in order to extract pure cellular fluorescent signals. Different scanning methods were discussed for effective collection of the cellular fluorescent signal. The cell scanning technique results in many advantages, such as distinguishing a small part of a cell, allowing for background correction and monitoring the switch of reagents. In addition, it is possible to evaluate the photobleaching effects on both the background and cellular fluorescence, with the latter found to be less significant in a restricted cellular environment.

Fluorescence↗
PubMed1993

Blood analysis of mice born following single-cell embryo biopsy.

Single-cell embryo biopsy is an important technique in preimplantation diagnosis. The development of the mouse embryo and fetus, and the results of some analyses after birth following embryo biopsy, have been demonstrated to be normal. Histopathological analysis of mice born following single-cell embryo biopsy with a physical method (zona puncture) also showed normal organ and cell structure, thus demonstrating the safety of embryo biopsy. This experiment analysed the parameters of blood cells and the blood chemistry of 28 mice born following single-cell embryo biopsy. White cell count, red cell count, haemoglobin level and platelet count of the blood, and plasma sodium, potassium, chloride, bicarbonate, calcium, glucose, albumin, protein, creatinine, urea, bilirubin, aspartate transaminase, creatine kinase and lactate dehydrogenase of the blood were not significantly different between the mice from the biopsied and the control embryo groups, which again demonstrated the safety of single-cell embryo biopsy. The remaining totipotent cells in the biopsied embryos would thus be expected to develop to the correct cell counts and normal organic functions according to the intact hereditary messages. Further studies on the safety of embryo biopsy (including long-term observation after birth) and the improvement of the different biopsy techniques and skills for preimplantation diagnosis are necessary.

Animals↗
PubMed2000

From hormone signal, via the cytoskeleton, to cell growth in single cells of tobacco.

Cultured mesophyll protoplasts of Nicotiana tabacum L. can be hormonally induced into different developmental pathways. In a medium containing auxins (NAA) and cytokinins (BAP) cells divide and eventually give rise to calli. When only auxins are present cells elongate and finally differentiate into very long tubular cells. We focused on the sequence of events leading to elongation. When cultured in a high (1 mg/l) auxin concentration elongating cells seem to pass a certain threshold and increase their nuclear DNA up to about 16C. Cells cultured in a low (0.065 mg/l) auxin concentration only have C-values up to 4C, are unable to pass this threshold and finally fail to elongate. Besides the concentration dependence of the auxin signal, the efflux of auxin seems to be necessary for elongation since addition of TIBA drastically reduces the amount of elongating cells. Concomitant with the changes in nuclear physiology, auxin-induced axiality is seen as sequential rearrangements of microtubules and actin-filaments and of cell wall cellulose microfibrils from 'randomly' arranged in spherical cells to an orientation perpendicular to the long axis of elongating cells.

Adenine↗
PubMed2000

Evaluation of benzo(a)pyrene-induced DNA damage in human endothelial cells using alkaline single cell gel electrophoresis.

The alkaline version of the 'comet assay' was used to evaluate DNA damage in human umbilical vein endothelial cells (HUVEC) exposed to 0.1, 1.0, or 10 microM benzo(a)pyrene for 90min. The genotoxicity was monitored in HUVEC pretreated with the Ah-receptor agonist beta-naphthoflavone (BNF), previously shown to induce cytochrome P4501A1 (CYP1A1) activity in these cells, and in vehicle-treated HUVEC with only constitutive levels of this enzyme. Increased DNA damage was observed only in cells that had been exposed to 10 microM benzo(a)pyrene, cells exposed to BNF being subjected to the most extensive damage. The CYP1A/B-inhibitor alpha-naphthoflavone (ANF) reduced the benzo(a)pyrene-induced DNA-damage in the BNF-treated HUVEC to the same level as in the uninduced cells. The fact that benzo(a)pyrene induced DNA damage in vehicle-treated HUVEC suggests that there may be at least one alternative route of bioactivation for benzo(a)pyrene in these cells. Consequently, judging from the present results it seems as if tobacco-related polycyclic aromatic hydrocarbons (PAHs) may disrupt the function of the endothelial lining in blood vessels with low monooxygenase activity. It is proposed that exposure to Ah receptor agonists via, for example, tobacco smoke, may enhance the DNA-damaging effects of smoke-related genotoxic PAHs in human endothelial cells. The role of PAHs in endothelial dysfunction of tobacco smokers should therefore be further studied.

Animals↗
PubMed1997

Cytokine and chemokine production by CD34+ haemopoietic progenitor cells: detection in single cells.

In vitro expansion of haemopoietic progenitor cells (HPC), lineage-specific differentiation, and gene transfer are all based on in vitro culture systems using haemopoietic growth factors (HGF). A close control of the actual culture conditions, however, is difficult due to secondary mediators secreted by the heterogenous population of mature and immature cells in culture. Although monocytes and granulocytes have already been identified as active producers, this study specifically addressed the role of CD34+ progenitor cells in this respect. Using an immunostaining method that enables simultaneous detection of cytokines and phenotype, 56 +/- 6% CD34+ peripheral blood progenitor cells (PBPC) were found to contain cytoplasmic IL-8 after stimulation with phorbol myristate acetate + ionomycin for 90 min. 19 +/- 40%, stained positive after TNF-alpha induction (20 h), and 7 +/- 1% expressed IL-8 in the presence of culture medium alone. Intra-cytoplasmic TNF-alpha and IL-1beta were detected at lower frequency, and < 1% of CD34+ cells expressed IL-1ra or IL-6, whereas IL-1alpha, IL-10 and G-CSF were not detected. Thus, CD34+ HPC are able to synthesize chemo- and cytokines that may operate in an auto- or paracrine manner to modulate in vivo as well as in vitro growth and differentation of haemopoietic cells.

Antigens, CD34↗
PubMedDate not supplied

Detection of a feline X-linked antigen in somatic cell hybrids. Single-cell analysis using monoclonal antibodies.

We tested the premise that monoclonal antibodies to either intracellular or membrane antigens can greatly facilitate the construction of linkage maps of mammals whose chromosomes can be introduced into rodent cells. Monoclonal antibodies against antigenic determinants of cat lymphocytes and fibroblasts were used to analyze feline antigen expression in cat-mouse somatic cell hybrid populations selected to contain the X-linked feline HPRT locus. The frequency of antigen expression as measured by fixed cell immunofluorescence (IF) assays, varied greatly within hybrid populations for all but the antigen designated as VP382. Its frequent presence in hybrid cells led to the prediction, confirmed by 8-azaguanine selection experiments, that its expression was controlled by a gene, or genes, on the feline X chromosome. The antigens identified by the rest of the antibodies segregated independently of each other in cat-mouse somatic cell hybrids and their expression appeared to be controlled by autosomal genes of the cat.

Animals↗
PubMed2002

[Detection of cell apoptosis induced with anti-Fas antibody in bladder carcinoma cell line by single cell gel electrophoresis].

BACKGROUND & OBJECTIVE: Fas, a death factor, can induce apoptotic death of cells. Many malignant tumor cells expressed Fas can not develop apoptotic death, this may be because of low Fas expression. Therefore we investigate the relationship between expression level of Fas and anti-Fas biological responsiveness. METHODS: With direct immunofluorescence flow cytometry, the expression of Fas was detected in bladder carcinoma cell line EJ, TNF alpha treated EJ, and Fas gene transfected EJ. The three kinds of EJ cells died by apoptosis were induced with anti-Fas antibody DX2 IgG1K and determined by SCGE and flow cytometry (FCM). RESULTS: Expression of Fas in bladder carcinoma cell line EJ, TNF alpha treated EJ, and Fas gene transfected EJ was 19.18%, 28.03%, and 68.69%, respectively. Cellular apoptosis induced with anti-Fas antibody DX2 IgG1K in bladder carcinoma cell line EJ was least, in TNF alpha treated EJ moderate, and in Fas gene transfected EJ the most. CONCLUSIONS: Fas gene transfection is an effective method to increase Fas expression; the sensitivity of EJ cell line to Fas-mediated apoptosis is mainly dependent upon the expression of Fas.

Antibodies, Monoclonal↗
PubMed2001

MDM2 gene amplification and lack of p53 point mutations in Hodgkin and Reed-Sternberg cells: results from single-cell polymerase chain reaction and molecular cytogenetic studies.

Hodgkin's disease (HD) is the most common haematological malignancy after chronic lymphocytic leukaemia, but very little is known about its pathogenesis or the genetic events that contribute to the malignant phenotype of the tumour cells. p53 is assumed to play an important role in the pathogenesis of HD, based on the observation that p53 protein is frequently accumulated in Hodgkin and Reed-Sternberg (H & RS) cells. We investigated single H & RS cells from five different HD patients for point mutations at the genomic level using multiplex polymerase chain reaction amplification and subsequent sequencing. No point mutations were detected in 50 single H & RS cells analysed. Hence, accumulation of p53 protein cannot be explained by mutations within the gene. A genome-wide screening for genomic imbalances using comparative genomic hybridization revealed gain on chromosome 12q14, i.e. the mapping position of the MDM2 gene in several HD cases. Therefore, we assessed the copy number of the MDM2 gene using fluorescence in situ hybridization. In four out of six HD cases analysed, the copy number of the MDM2 gene was found to be increased. As gene amplification is frequently associated with protein overexpression, the observed accumulation of p53 in the nuclei of H & RS cells could be as a result of elevated MDM2 protein levels resulting in stabilization of p53 protein.

Adult↗