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At least 613 records · Page 34Linked to original sources
PubMed1985

Potential genetic gains from producing bulls with only sires as parents.

Micromanipulation of sperm and ova has been suggested as a means to produce progeny of two sires instead of a sire and dam. Selection schemes taking advantage of this technology could produce genetic gains 1.5 to 2 times current gains. An optimum strategy both genetically and economically would be to breed 99% of the population to young sires and 1% to progeny-tested sires. The genetic pathway from sires to sons could become the only pathway affecting genetic gain; this would eliminate problems of cow evaluation and would give artificial insemination organizations more control over quality of young sires. Inbreeding would not be a problem, and few other technologies could offer superior rates of genetic gain.

Animals↗
PubMed1999

[Sex determination of human preimplantation embryo blastomere using dualcolor fluorescence in situ hybridization].

OBJECTIVE: To establish a series of techniques of sex determination of human preimplantation embryo in order that preimplantation genetic diagnosis(PGD) can be used clinically. METHODS: Use micromanipulation for biopsy of human preimplantation embryo(3-10 cell) and prepare single-cell interphase nuclei sample. Make sex determination of human preimplantation embryos by using dual-color fluorescence in situ hybridization. RESULTS: The technique of human preimplantation embryo (3-10 cell) biopsy was established preliminarily and the technique of preparing single-cell interphase nuclei sample was set up and stabilized. The sex determination of the blastomere of human preimplantation embryo was successful. CONCLUSION: This series of techniques can make fast diagnosis (less than 6 hours) with minimal sample(only one cell), with no cell culture, and with high accuracy of sex determination (100%).

Blastocyst↗
PubMed2000

Novel approach to cell sampling from preimplantation ovine embryos and its potential use in embryonic genome analysis.

The major obstacle in the extensive analysis of the embryonic genome is the small number of cells typically obtained after the embryo biopsy. The object of the present study was to develop a simple approach that would allow the collection of a sufficient number of cells from a single embryo for use in further analyses. A micromanipulator was used to make a hole in the zona pellucida of 28 compacted morulae, 27 early blastocysts and 31 expanded blastocysts. After further culture, the trophoblastic cells, which herniated through this hole, were cut and cultured in vitro for different periods and used for embryo sexing. The results showed that biopsies can be taken successfully from 96.3% of early blastocysts, compared with 67.7% of expanded blastocysts and 71.4% of compacted morulae. The trophoblastic vesicles contained 20.8 +/- 6.7 cells (mean +/- SEM) and, when cultured, formed a confluent monolayer. The sex of cells cultured was assayed by PCR and the 12 lambs born after transfer of biopsied embryos confirmed its 100% accuracy. Moreover, no significant differences were found in the viability rates in vitro among blastocysts vitrified immediately after biopsy (77.8%), blastocysts biopsied and vitrified after 24 h culture (76.9%) and blastocysts vitrified without manipulation (88.5%). In experiments in vivo, the lambing rate of biopsied and vitrified blastocysts was significantly (P < 0.05) lower (40.0%) compared with vitrified control embryos (68.7%). This new approach to the biopsy of preimplantation embryos is a useful good model in the assisted reproductive technologies of domestic, wild and human species.

Animals↗
PubMed1975

Study of the specificity of the action of adhesive factors isolated from the liver and lungs of adult mice and rats.

Adhesive factors (AF), enhancing the cohesion of cells in liver and lung tissues, were isolated from the liquid obtained in the incubation of pieces of liver and lung of adult mice and rats in calcium-free salt solution. The action of AF was evaluated according to their influence on the strength of cohesion of the cells in the lung and liver, measured with a micromanipulator, and according to the number of cells isolated from the liver by dispersion. The presence of tissue specificity and the absence of species specificity of the action of AF on the tissues of adult animals was demonstrated.

Animals↗
PubMed2001

Cell sampling and analysis (SiCSA): metabolites measured at single cell resolution.

By using a fine oil-filled glass microcapillary mounted on a micromanipulator, the solutes of individual plant cells can be sampled. These samples can then be analysed using a range of physical and chemical methods. Hydrostatic pressure (cell pressure probe), osmotic pressure (picolitre osmometer), organic solutes (enzyme-linked fluorescence microscope spectrometry or capillary electrophoresis), inorganic solutes (X-ray microdroplet analysis or capillary electrophoresis), (14)C (mass spectrometry), proteins (microdroplet immunoblotting), and mRNA (rt PCR) have been measured. Collectively, the battery of techniques is called single cell sampling and analysis (SiCSA) and all of the techniques have relevance to the study of plant metabolism at the resolution of the individual cell. This review summarizes the techniques for SiCSA and presents examples of applications used in this laboratory, in particular those relating to cell metabolism.

Cells↗
PubMed2002

Rapid isolation of cancer cells from tumor tissue by micromanuiplator and extraction of tiny amount of RNA.

OBJECTIVE: To establish a rapid method for isolating and purifying cancer cells from tumor tissue and for RNA extraction from tiny amount of the cells thus obtained. METHODS: Frozen sections of the tumor tissues were prepared followed by rapid staining. Clusters of the cancer cells were isolated from the sections by micromanipulation technique and purified for extracting intact RNA that was subsequently assayed. RESULTS: Clear vision was achieved by the staining of the sections. The cancer cell clusters were precisely isolated from which high-quality intact RNA was obtained as demonstrated by reverse transcriptase-PCR. CONCLUSION: Micromanuiplation can be effectively used in stead of laser capture microdissection to isolate and purify targeted cells from tiny amount of tissue samples, therefore making RNA extraction possible in this context.

Electrophoresis, Agar Gel↗
PubMed2003

Mechanical assessment by magnetocytometry of the cytosolic and cortical cytoskeletal compartments in adherent epithelial cells.

This study aims at quantifying the cellular mechanical properties based on a partitioning of the cytoskeleton in a cortical and a cytosolic compartments. The mechanical response of epithelial cells obtained by magnetocytometry - a micromanipulation technique which uses twisted ferromagnetic beads specifically linked to integrin receptors - was purposely analysed using a series of two Voigt bodies. Results showed that the cortical cytoskeleton has a faster response ( approximately 1 s) than the cytosolic compartment ( approximately 30 s). Moreover, the two cytoskeletal compartments have specific mechanical properties, i.e., the cortical (resp. cytosolic) cytoskeleton has a rigidity in the range: 49-85 Pa (resp.: 74-159 Pa) and a viscosity in the range 5-14 Pa.s (resp.: 593-1534 Pa.s), depending on the level of applied stress. Depolymerising actin-filaments strongly modified these values and especially those of the cytosolic compartment. The structural relevance of this two-compartment partitioning was supported by images of F-actin structure obtained on the same cells.

Actins↗
PubMed2003

Characterization of cytoskeleton mechanical properties and 3D-actin structure in twisted adherent epithelial cells.

Evaluation of the cytoskeleton mechanical properties requires specific micromanipulation techniques such as the magnetic twisting cytometry technique, in which microbeads are specifically linked to the cytoskeleton via transmembrane receptors. The aim of the study was to assess the structural relationship between the bead and the cytoskeleton structure. The spatial arrangement of the CSK network was therefore studied in fixed cells probed by beads and stained for F-actin by rhodamined phalloïdine. The spatial character of the actin CSK network, both in the bead neighborhood and at the cell scale, could then be studied for various degrees of fluorescent intensity from 3D-images of the actin structure, reconstructed from z-stack views obtained by confocal microscopy. Results show the feasibility of the staining/reconstruction technique which allows to reveal the three-dimensional organization of the cytoskeleton structure including an internal cytosolic structure with a high fluorescent F-actin intensity, and a sub-membranous cortical structure with a low fluorescent F-actin intensity.

Actins↗
PubMed2003

Elasticity of the human red blood cell skeleton.

We have measured by optical tweezers micromanipulations the area expansion and the shear moduli of spectrin skeletons freshly extracted from human red blood cells, in different controlled salinity conditions. At medium osmolarity (150 mOsm/kg), we measure KC=9.7+/-3.4 microN/m, muC=5.7+/-2.3 microN/m, KC/muC=2.1+/-0.7. When decreasing the osmolarity, both KC and muC decrease, while KC/muC is nearly constant and equal to about 2. This result is consistent with the predictions made when modeling the spectrin skeleton by a two-dimensional triangular lattice of springs. From the measured elastic moduli we estimate the persistence length of a spectrin filament: xi approximately 2.5 nm at 150 mOsm/kg.

Elasticity↗
PubMed2003

Typing the histogenetic origin of the tumor cells of lymphocyte-rich classical Hodgkin's lymphoma in relation to tumor cells of classical and lymphocyte-predominance Hodgkin's lymphoma.

Hodgkin's lymphoma (HL) is separated into the classical (c) and lymphocyte-predominance (lp) forms. Whereas classical Hodgkin-Reed/Sternberg (HRS) cells carry mutated immunoglobulin (Ig) gene rearrangements that are often "crippled" and lack intraclonal diversity, and are likely derived from preapoptotic germinal center (GC) B cells, the lymphocytic and histiocytic cells of lpHL are presumably derived from selected GC B cells and often show ongoing somatic hypermutation. The recently identified lymphocyte-rich classical (lrc) HL is characterized by HRS cells with the immunophenotype of classical HRS cells (CD30(+)CD15(+)CD20(-)CD45(-)) but an infiltrate similar to lpHL and a clinical behavior resembling lpHL. To identify the histogenetic origin of the HRS cells in lrcHL and to determine the relationship to the lymphoma cells of cHL and lpHL we characterized seven cases of lrcHL by immunohistochemistry and sequenced the rearranged Ig genes of single micromanipulated HRS cells. The expression patterns of BCL6, CD138, Oct2, and BOB1 in HRS cells of lrcHL showed differences to those of both cHL and lpHL. Analyses of rearranged Ig genes identified clonal HRS cell expansions carrying mutated Ig rearrangements without significant intraclonal diversity in all seven of the cases. In two cases crippling mutations, rendering originally functional V gene rearrangements nonfunctional, were observed. Thus, the mutation pattern of rearranged Ig genes of HRS cells in lrcHL is clearly different from those in lymphocytic and histiocytic cells of lpHL, and resembles the pattern in HRS cells of cHL, suggesting that HRS cells in lrcHL derive from (preapoptotic) GC B cells that silenced hypermutation. In one case in addition to the dominant HRS cell clone, CD30(+) EBV-infected HRS-like cells unrelated to the tumor clone were observed, suggesting development of an expanded population of EBV-harboring HRS-like cells in the microenvironment of HL.

Adult↗
PubMed1992

Ethical issues and controversies in assisted reproductive technologies.

The current ethical issues and controversies concerning in vitro fertilization revolve around micromanipulation of the gametes, cryopreservation of the fertilized ova, selective termination in multiple pregnancies, surrogacy, and gamete donation. At the basis of these ethical issues is the philosophic question of personhood, or the term "human person," and the consideration given to the normal weight that is ascribed to the various forms of living matter that are found in the process of development after human spermatozoa have been placed together with harvested oocytes in the petri dish. The papers of very special importance and special importance written during the past year on these ethical problems are listed and classified. The summaries of their arguments and positions on these problems are enumerated.

Abortion, Induced↗
PubMed1992

[Microencapsulation in Na-alginate and in vitro development of sheep blastomeres].

Embryos at 4 cell stage obtained from Sarda ewes superovulated with FSHp (Sigma) were micromanipulated in order to obtain single blastomeres (1/4 E). The 1/4 E have been located randomly in two groups. In the first (Group A n. 30) the 1/4 E have been put back in empty zonae pellucidae; in the second (Group B n. 21) they have been microencapsulated in sodium alginate (1.1%) by dropping cell-alginate solution in a 1.5% CaCl2. Each capsule (1 mm diameter) contained four 1/4 E. The blastomeres have been co-cultured for 5 days in CZB medium on oviductal cell monolayer in a humidified incubator (5% CO2, 95% air, 38.5 degrees C). No differences were found between the groups reaching blastocyst stage after the end of the culture period (A 50%-B 47%).

Alginates↗
PubMed2005

[Laser assisted intracytoplasmic sperm injection: a more effective and faster technique of immobilization of spermatozoa than traditional one].

AIM: Intracytoplasmic sperm injection (ICSI) is employed routinely in the assisted reproductive technique, in particular in case of male factor infertility. Recently, some options have been introduced in the micromanipulation system employed in ICSI, improving the performance of this technique. One of these is a no-contact laser, mostly used for the assisted hatching and the blastomere biopsy in preimplantation genetic diagnosis. One of the most important step of the ICSI technique is the sperm immobilization. Normally, this is performed by the operator and needs some time. METHODS: A one-year perspective-comparative study has been carried out and the results obtained with the traditional technique of immobilization of spermatozoa have been compared with those obtained with the laser technique (spermatozoa previously immobilized by no-contact laser). We have evaluated 3 parameters: 1) fertilization rate; 2) cleavage rate and 3) time needed to immobilize sperm. RESULTS: Some interesting findings have been observed: the embryo quality, fertilization rate and cleavage rate seem the same in both groups. The most interesting finding is the drastic reduction of the time needed for microinjection when the laser technique is used. CONCLUSIONS: This technique will reduce the total time needed to perform the ICSI, decreasing the time of exposure of the gametes outside the incubator and reducing the possibility of irreversible damage.

Adult↗
PubMed1989

A protocol used for splitting mouse embryos into two halves.

8-16 cell embryos and early blastocysts were obtained from the oviducts and anterior portion of uterine horns of albino mice at 70 and 90 hr after LH injection respectively. Splitting of embryos was done by using two microtools attached to a micromanipulator unit (Research Instruments Ltd, UK). After bisection, each pair of the half embryos is transferred to a dish containing 2 ml of T-6 medium and cultured in CO2 incubator (at 39 degrees C, 95% RH and 5% CO2 in air mixture). Splitting of blastocysts as compared to 8-16 cell embryos was found difficult (35.48% vs 52.44%, respectively). 38.88% of bisected 8-16 cell embryos and 11.36% of bisected blastocysts developed on 48 hr culture. Information on splitting mouse embryos and their subsequent development in culture are significant in view of using the technique for commercial application and for research in developmental biology of animal embryos.

Animals↗
PubMed1983

Minimal infectious doses and prepatent periods in Giardia muris, Spironucleus muris and Tritrichomonas muris.

The minimal infectious doses (MID) of Giardia muris cysts, Spironucleus muris cysts and Tritrichomonas muris pseudocysts for athymic mice were determined. A novel micromanipulator-aided technique was developed for selecting small exact numbers of specified fresh or old cysts/pseudocysts from a faecal homogenate. This technique can also be of value in manipulating protozoan parasites of any particular species. Only fresh cysts/pseudocysts, which appeared bright under phase contrast optics, were infectious. Older cysts and pseudocysts which appeared dark in phase contrast were not infectious. The MID for three murine intestinal flagellates addressed above were: 10 (between 5 and 20), 1 and 5 cysts/pseudocysts respectively. Corresponding prepatent periods (PP) were 8, 5 and 10 days. A relation was evident between the infectious dose and the PP: The prepatent period shortened with an increased infectious dose.

Animals↗
PubMed1984

Analysis of differentiation of mouse hemopoietic stem cells in culture by sequential replating of paired progenitors.

Blast cell colonies seen in cultures of spleen cells from 5-fluorouracil-treated mice provide a highly enriched population of primitive hemopoietic progenitors. Our recent studies of the differentiation potentials of the paired daughter cells of these progenitors showed different patterns of differentiation in the colonies produced by the separated daughter cells. In this study, we carried out sequential micromanipulation of paired progenitors followed by cytologic examinations of the colonies derived from these progenitors. Of the total 94 evaluable cultures, consisting of three or more colonies, 52 consisted of macrophage colonies and one consisted of megakaryocyte colonies. In the remaining 41 cultures, diverse combinations of colonies revealing heterogeneous compositions of cell lineages were identified. Presumptive genealogic trees of the differentiation of hemopoietic progenitors constructed for the latter group of cultures suggested that monopotent progenitors may be derived from pluripotent progenitors in two ways: (1) directly during one cell division of pluripotent cells or (2) as a result of progressive lineage restriction during successive division of the pluripotent progenitors. The results also suggested that some of the oligopotent progenitors are capable of limited self-renewal.

Animals↗
PubMed1995

Assisted reproductive technology in the United States and Canada: 1993 results generated from the American Society for Reproductive Medicine/Society for Assisted Reproductive Technology Registry.

OBJECTIVE: To summarize the procedures and outcomes of assisted reproductive technology (ART) initiated in the United States in 1993. DESIGN: Data were collected on an annual summary form and submitted to the American Society for Reproductive Medicine/Society for Assisted Reproductive Technology Registry. PARTICIPANTS: Two hundred sixty-seven programs submitted data on procedures performed in 1993. Data were collected in October 1994 so that outcome of all pregnancies established would be known. MAIN OUTCOME MEASURES: The outcomes measured included clinical pregnancy, ectopic pregnancy, abortion, stillbirth, delivery, and congenital abnormality. RESULTS: Programs reported initiations of 41,209 cycles of ART treatment, excluding frozen embryo and donor oocyte cycles. Of these, 33,543 cycles initiated were IVF (standard, with micromanipulation, and for host uterus transfer) with 18.3% deliveries per retrieval; 4,992 were cycles of GIFT with 28.1% deliveries per retrieval; 1,792 were cycles of ZIFT with 24.4% deliveries per retrieval; and 882 were combination cycles, combining IVF and one of the tubal transfer techniques, resulting in 27.8% deliveries per retrieval. In addition to these cycles initiated in 1993, 6,869 frozen ET procedures were reported, either as separate procedures or in combination with another ART procedure with 13.3% deliveries per procedure, and 2,766 donor oocyte cycles were initiated with an overall success of 30.2% deliveries per retrieval. As a result of all procedures, a total of 8,741 deliveries were reported. CONCLUSIONS: In 1993, there were more programs offering more treatment cycles of ART. Overall average success rates (deliveries per procedures) exhibited only a small increase compared with previously reported summaries.

Adult↗
PubMed1994

Optical manipulations of human gametes.

Optical manipulations of human gametes are described indicating their potential for use in in vitro fertilization and preimplantation-assisted zona pellucida hatching. Successful manipulations are demonstrated using focused laser beams in association with microscopy. The micromanipulation and selection of male gametes were achieved using an optical-trapping infrared laser diode. The opening of the zona pellucida surrounding the egg (assisted hatching) was performed using a pulsed, nitrogen-pumped dye laser. Clinical applications for laser-assisted reproduction techniques are discussed.

Female↗