Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MICROMANIPULATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,423 records · Page 79Linked to original sources
PubMed2000

Cells of different ploidy are often present together in Cryptococcus neoformans strains.

We examined the ploidy of C. neoformans strains using both laser scanning cytometry and a fluorescence microscope equipped with a photomultiplier. Haploid strains consisted of normal-sized cells with a haploid DNA amount. In the cell population there were also large-sized cells with a diploid DNA amount. These large cells in haploid strains were isolated using a Skerman micromanipulator, cultivated, and were able to generate diploid clones. Even after only 3-5 transfers on slants, haploid cells were present in all the diploid clones examined. Conversely, haploid clones obtained by single-cell-isolation of normal-sized cells from haploid strains were also shown to contain diploid cells after 3-5 transfers. Fresh haploid isolates from the environment similarly contained diploid cells after 3-5 transfers. Thus, a cellular ploidy shift was shown to occur widely in C. neoformans strains.

Cryptococcus neoformans↗
PubMed1990

Current trends in human IVF and other assisted reproductive technologies.

The new reproductive technologies such as IVF, GIFT, ZIFT, and micromanipulation have had a profound influence on the therapeutic and diagnostic management of infertility, and in turn have resulted in better understanding of human fertilization and embryo development. While the clinical pregnancy rates in GIFT and ZIFT procedures are comparable to the natural fecundity in the population at large, pregnancy rates in IVF have been generally lower. Further investigations should be directed to improve the implantation rates, and to develop better controlled methods of multiple follicle development. Although more studies are needed, a recent report of potential utilization of nonstimulated oocytes for donor programs as well as IVF-cryopreservation was a promising new development (Cha et al. 1989). Other exciting prospects on the horizon are the possibilities of gene transfer for the treatment of certain genetic diseases and diagnostic applications of embryonal biopsy. These new technologies have also generated serious ethical and legal issues. Any ethical or legal guidelines affecting new reproductive technologies should be developed to protect all participants only when the need for regulation is clear. Ethical guidelines and appropriate legislations with contributions from the medical and scientific community are gradually being established worldwide.

Cryopreservation↗
PubMed1989

Manipulation of avian primordial germ cells and gonadal differentiation.

The authors hypothesized that donor primordial germ cells (PGC) are useful as vehicles of gene transfer in birds. The PGC have been identified in the blastula prior to incubation. They have been isolated from the Stage 7 germinal crescents, Stage 17 blood, and Stage 30 gonads. The percentages of PGC in these three embryonic sources were 2, .003 and 1.5%, respectively. The isolated PGC have been used as antigens to produce specific antibodies that have served as major tools in identification, isolation, and forming enriched in vitro cultures of PGC. Sterile hosts for normal donor PGC have been induced by use of ultraviolet irradiation, treatment with the chemical busulfan, and crossing rooster with female quail to form a sterile host termed "quickens." Micromanipulator technology, along with refinement of techniques to avoid trauma, will allow 80% hatchability. Integration of all the above biotechnology has led to successful use of PGC as vehicles of gene transfer and production of autogenic quail.

Animals↗
PubMed2003

Gene-expression analysis of single cells-nested polymerase chain reaction after laser microdissection.

AIM: The structural and functional characteristics of cells are dependent on the specific gene expression profile. The ability to study and compare gene expression at the cellular level will therefore provide valuable insights into cell physiology and pathophysiology. METHODS: Individual cells were isolated from frozen colon tissue sections using laser microdissection. DNA as well as RNA were extracted, and total RNA was reversely transcribed to complementary DNA (cDNA). Both DNA and cDNA were analyzed by nested polymerase chain reaction (PCR). The quality of isolated DNA and RNA was satisfactory. RESULTS: Single cells were successfully microdissected using an ultraviolet laser micromanipulator. Nested PCR amplification products of DNA and cDNA of single cells could clearly be visualized by agarose gel electrophoresis. CONCLUSION: The combined use of laser microdissection and nested-PCR provides an opportunity to analyze gene expression in single cells. This method allows the analysis and identification of specific genes which are involved in physiological and pathophysiological processes in a complex of variable cell phenotypes.

Colon↗
PubMed2002

Distinct clonal Ig diversification patterns in young appendix compared to antigen-specific splenic clones.

The young rabbit appendix is a dynamic site for primary B cell repertoire development. To study diversification patterns during clonal expansion, we collected single appendix B cells from 3- to 9-wk-old rabbits and sequenced rearranged H and L chain genes. Single cells obtained by hydraulic micromanipulation or laser capture microdissection were lysed, PCR amplified, and products directly sequenced. Gene conversion-like changes occurred in rearranged H and L chain sequences by 3-4 wk of age. Somatic mutations were found in the D regions that lack known conversion donors and probably also occurred in the V genes. A few small sets of clonally related appendix B cells were found at 3-5 wk; by 5.5 wk, some larger clones were recovered. The diversification patterns in the clones from appendix were strikingly different from those found previously in splenic germinal centers where an immunizing Ag was driving the expansion and selection process toward high affinity. Clonally related appendix B cells developed different amino acid sequences in each complementarity-determining region (CDR) including CDR3, whereas dominant clones from spleen underwent few changes in CDR3. The variety of combining sites generated by diversification within individual clones suggests that at least some clonal expansion and selection, known to require normal gut flora, may be driven through indirect effects of microbial components rather than solely by their recognition as specific foreign Ags. This diversity of combining sites within B cell clones supports the proposed role of appendix in generating the preimmune repertoire.

Amino Acid Sequence↗
PubMed1993

[Ultrastructure of immotile spermatozoa obtained from infertile male patients].

We sometimes experienced infertile patients whose sperms had no motility but were not stained by Eosin Y. In this paper we report five cases of so-called "immotile spermatozoa". The ultrastructure of sperm tails was examined by transmission electrone microscope (TEM). These cases were selected from the out-patient population who attended infertility clinic of our department. The semen analyses showed that all the cases had sperm motility below 1% and more than 90% of the spermatozoa were proven alive. Family history revealed that one case had an infertile sibling. None of them had situs inversus, bronchiectasis and chronic sinusitis which are classic trias of Kartagener's syndrome. They had no symptoms of upper respiratory tract infection which was caused by the abnormality in the flagella of the respiratory tract. The TEM pictures of sperm tails showed partial deletion of inner dynein arms in two cases, lack of central microtubular doublets (so-called 9 + 0) in two cases and disarrangement of microtubular doublets in one case. For the treatment of these cases there is no effective means but AID. However, the rapid progress of IVF-ET techniques and a report that the spermatozoa from Kartagener's syndrome had showed penetration into eggs encouraged us to think the micromanipulation of spermatozoa with IVF-ET as a hopeful option of the treatment in the near future.

Adult↗
PubMed1999

Plasma cell development in synovial germinal centers in patients with rheumatoid and reactive arthritis.

Plasma cells are found surrounding the inflammatory infiltrates of macrophages, T, and B cells in the synovial tissue of patients with rheumatoid and reactive arthritis. This characteristic arrangement suggests that in the synovial tissue CD20+ B cells differentiate into plasma cells. To examine clonal relationships, we have used micromanipulation to separately isolate CD20+ B cells and plasma cells from single infiltrates. DNA was extracted, and from both populations the VH/VL gene repertoires was determined. The data show that in the inflamed synovial tissue activated B cells are clonally expanded. During proliferation in the network of follicular dendritic cells, V gene variants are generated by the hypermutation mechanism. Surprisingly, we do not find identical rearrangements between CD20+ B cells and plasma cells. Nevertheless, the finding of clonally related plasma cells within single infiltrates suggests that these cells underwent terminal differentiation in the synovial tissue. These results indicate that B cell differentiation in the synovial tissue is a dynamic process. Whereas CD20+ B cells may turnover rapidly, plasma cells may well be long lived and thus accumulate in the synovial tissue. The analysis of individual B cells recovered from synovial tissue opens a new way to determine the specificity of those cells that take part in the local immune reaction. This will provide new insights into the pathogenesis of chronic inflammatory diseases like rheumatoid or reactive arthritis.

Adolescent↗
PubMed1997

[The role of opioid receptors of arcuate nucleus in cytokine-induced hyperthermia].

The present study is to define the role played by the opioid receptors of ARH in the regulation of body temperature. 1 microliter of IL-1 beta (as pyrogen) was injected into the ARH of male Sprague-Dawley rat with an automatic micromanipulator to induce hyperthermia. 30 minutes prior to the injection of pyrogen, the experimental groups were pre-treated with general opioid receptor antagonist naloxone (Nal), selective mu, delta, kappa receptor antagonists CTAP, NTI, nor-BNI respectively. Controls were pre-treated with saline. The results showed that IL-1 beta-induced hyperthermia was blocked by Nal and CTAP, suggesting the involvement of, or mediation by, ARH opioid receptors (mainly the mu type) in IL-1 beta-induced hyperthermia. The blockade by delta and kappa antagonists was not remarkable. Thus their participation in this process is less likely. The similarity between the roles of opioid receptors of ARH and POAH in IL-1 beta-induced hyperthermia strongly supports the view that ARH may be an important component of the thermoregulatory center.

Animals↗
PubMed1999

Teratozoospermia and its effect on male fertility potential.

Teratozoospermia and its significance for male fertility problems is discussed. Different points of view and available information concerning the phenomenon of teratozoospermia have been presented. Ongoing debate about the influence of sperm morphology on male infertility and IVF results emphasizes the fact that when sperm morphology is evaluated using strict criteria, this parameter is thought to have an excellent predictive value and shows a significant positive correlation with successful fertilization. Selective abilities of zona pellucida to differentiate between morphologically normal and abnormal spermatozoa, the superior role of acrosomal morphology assessment in the prediction of IVF outcome, and the involvement of cell surface molecules in the adhesion of spermatozoa to oocytes are described. The usefulness of the hamster oocyte penetration assay (HOPA), which is important not only because of its predictive value of sperm function, but also because of its role as a tool for visualizing sperm chromosomes, was found to be questionable in cases of teratozoospermia. Cytogenetic findings related to teratozoospermia are controversial as classical methodology of visualizing sperm chromosomes (through HOPA) may cause selection of sperm metaphases which can be obtained only from good-penetrating spermatozoa. There are few reports presenting chromosome complements of abnormal sperm visualized with the help of micromanipulation. There is clear evidence that a variety of genetic defects can affect spermatogenesis. The possible genetic background of teratozoospermia is discussed.

Animals↗
PubMed1991

Effect of CO2 laser beam angle of incidence in the oral cavity.

In the oral cavity of white rats a series of experiments were made by CO 2 laser beam, by handpiece, micromanipulator, and an operation microscope. The authors examined the extent of the damaged tissue on the surface and in the depth of the wound. They established that in the case of 90 degrees angle of incidence--same power, exposition time and focus--the laser beam caused the deepest crater and the least damage to the surface. The decrease in the angle of incidence caused a decrease in the depth of the laser crater and increase in the surface. The 90 degrees angle of incidence CO 2 laser beam gives the optimal possibility for the precise elimination of the pathologic tissues on the surface and in the depth, without damaging the surrounding healthy structures. This operation not only protects the normal structures but also defends the physiological functions. In cases where it is not possible to apply the CO 2 laser beam at a minimum of an incidence of 60 degrees --the indirect way--the reflection has to be chosen. These aspects are important not only in the oral cavity but in other CO 2 laser operations.

Animals↗
PubMed1998

Telepresence interface with applications to microsurgery and surgical simulation.

To address the needs for performing microsurgical procedures, the SRI telepresence surgery workstation has been combined with a pair of micromanipulator arms. The prototype microsurgery system has been tested with ex-vivo tasks similar to those required for surgical procedures, such as cutting, grasping, suturing, and knot tying. Initial animal testing has been done on a rat model in which end-to-end anastomosis of the femoral artery (approximately 1 millimeter in diameter) was completed with ten rats, and 100% patency was obtained. To address the needs of surgical training, SRI has begun to develop a system that uses a 6-DOF telepresence workstation. A computer-generated stereo image is reflected in a mirror and appears to be superimposed on the surgeon's hands, creating an immersive and realistic environment. Tools held in the surgeon's hands are connected to left- and right-hand manipulators that both continuously measure tool position/orientation and apply force/torque to the tools. Furthermore, the visual image and tool locations are registered, so that the user perceives that he or she is looking at and moving the simulated tools in the visual image.

Animals↗
PubMed1999

Molecular analysis of single B cells from T-cell-rich B-cell lymphoma shows the derivation of the tumor cells from mutating germinal center B cells and exemplifies means by which immunoglobulin genes are modified in germinal center B cells.

T-cell-rich B-cell lymphoma (TCRBCL) belongs to the group of diffuse large cell lymphomas (DLL). It is characterized by a small number of tumor B cells among a major population of nonmalignant polyclonal T cells. To identify the developmental stage of the tumor progenitor cells, we micromanipulated the putative neoplastic large CD20(+) cells from TCRBCLs and amplified and sequenced immunoglobulin (Ig) V gene rearrangements from individual cells. In six cases, clonal Ig heavy, as well as light chain, gene rearrangements were amplified from the isolated B cells. All six cases harbored somatically mutated V gene rearrangements with an average mutation frequency of 15.5% for heavy (VH) and 5.9% for light (VL) chains and intraclonal diversity based on somatic mutation. These findings identify germinal center (GC) B cells as the precursors of the transformed B cells in TCRBCL. The study also exemplifies various means how Ig gene rearrangements can be modified by GC B cells or their malignant counterparts in TCRBCL: In one case, the tumor precursor may have switched from kappa to lambda light chain expression after acquiring a crippling mutation within the initially functional kappa light chain gene. In another case, the tumor cells harbor two in-frame VH gene rearrangements, one of which was rendered nonfunctional by somatic mutation. Either the tumor cell precursor entered the GC with two potentially functional in-frame rearrangements or the second VHDHJH rearrangement occurred in the GC after the initial in-frame rearrangement was inactivated by somatic mutation. Finally, in each of the six cases, at least one cell contained two (or more) copies of a clonal Ig gene rearrangement with sequence variations between these copies. The presence of sequence variants for V region genes within single B cells has so far not been observed in any other normal or transformed B lymphocyte. Fluorescence in situ hybridization (FISH) points to a generalized polyploidy of the tumor cells.

Adult↗
PubMed1999

Diagnosis of sex and cystic fibrosis status in fetal erythroblasts isolated from cord blood.

Diagnosis of fetal cells in the maternal circulation will obviate the need for invasive sampling procedures. It is essential however, before this can be put into wide clinical practice, that a reliable isolation procedure and a simple, robust means of genotyping rare fetal cells be developed. A relatively inexpensive, sensitive diagnostic procedure which can detect single gene defects and/or aneuploidy is fluorescent PCR. This has been used extensively in molecular diagnostics including preimplantation diagnosis but, to our knowledge, has not been applied widely for the diagnosis of isolated fetal erythroblasts. Here we used cord blood as a model system for fetal cells in the maternal circulation: we isolated erythroblasts on a glass slide, employed a simple micromanipulation technique to place them into a PCR tube and then applied fluorescent PCR to diagnose sex and cystic fibrosis status in 10 patients. Nine samples had a normal cystic fibrosis status, one patient, however, had a mutant allele suggesting that this fetus was a carrier for cystic fibrosis. Fluorescent PCR has virtually limitless potential in the genotyping of rare fetal cells isolated from the maternal circulation.

Cystic Fibrosis↗
PubMed1988

The Presbyterian-University Hospital, Pittsburgh. The gamma knife: brain surgery without an incision.

In July of 1987 a 20-ton gamma heavily shielded in a concrete "hot cell" was rolled into the basement of Presbyterian-University Hospital in Pittsburgh. Installation of the unit-one of only five in the world-and the first of its kind in the United States-was the culmination of 4.5 years of planning. It started in 1982 when the gamma knife was approved for marketing by the Food and Drug Administration. But because radioactive sources are sealed within the unit, it also had to be approved by the Nuclear Regulatory Commission (NRC), a process that required extensive and multiple levels of review within the nuclear agency. Although the device itself finally received NRC approval in 1986, the NRC Transportation Division refused to grant permission to transport a cobalt-loaded unit. So physicists at the University of Pittsburgh devised plans for on-site loading amidst the busy hospital environment in Pittsburgh! First a hot cell consisting of 3,000 lb of solid concrete block was constructed around the unit. Then, using robotic micromanipulators, the unit was loaded with 201 sources of cobalt-60, approximately 30 Ci each. The almost-6,000 Ci of cobalt provided a dosage rate of 396 cGy/min to the focal point, and patient treatment began one month later in August. Third-party reimbursement has been obtained from most major health insurance policies, and the procedure is approved for payment by Blue Shield and Medicare of Pennsylvania.

Brain Neoplasms↗
PubMed1999

Differentiation in culture of murine primitive lymphohematopoietic progenitors toward T-cell lineage.

Earlier, we described a stromal cell-free two-step clonal culture system in which murine primitive lymphohematopoietic progenitors produce myeloid and B-lymphoid lineage cells. In the same culture T-cell potential of the progenitors was maintained. We now report that, in addition to myeloid and B-lymphoid cells, putative T-cell progenitors are also produced in culture. Lineage-negative (Lin-) Ly-6A/E+ c-kit+ bone marrow cells from 5-fluorouracil-treated mice were cultured in methylcellulose in the presence of SF (Steel factor), interleukin (IL)-11, and IL-7, and the resulting primary colonies were picked and pooled. When injected into severe combined immune deficiency (scid) mice, the pooled cells reconstituted the T-cell compartment of the scid mice earlier than freshly prepared primitive marrow cells. This reconstitution activity of the pooled primary colony cells was enriched in the Ly-6A/E+ and FcgammaRII/III-/low cell fractions. Reverse transcriptase-polymerase chain reaction (RT-PCR) and DNA-PCR analyses showed that some of the primary colony cells are differentiated sufficiently to express messenger RNA (mRNA) of T-cell receptor (TCR) beta-chain and pre-TCR alpha (pTalpha) and, although not frequently, to perform Dbeta-Jbeta rearrangement of the TCR gene. Micromanipulation studies confirmed the clonal origin of myeloid lineage cells and the cells positive for the T-cell-specific transcripts and D-J rearrangement of TCR beta-chain. These results suggested that, in the presence of SF, IL-11, and IL-7, primitive lymphohematopoietic progenitors differentiate toward T-cell lineage in addition to myeloid and B-cell lineages.

Animals↗
PubMed1999

[Successful PMA. Review of the activities of the Center for Medically Assisted Procreation of University of Liege, 1985-1997].

Assisted reproductive treatments (ART) hold an increasing place in the field of female infertility but also of male infertility with the development of new micromanipulative technologies. From January 1985 to December 1997, more than 3,000 ovarian punctures were achieved at the CPMA of the University of Liege and more than 40,000 oocytes were recovered. Global results show a take home baby rate of 23% per ovum pick-up and 27% per embryo transfer. Embryo cryopreservation offers an efficient solution to the problem of supernumerary embryos and opens the way for IVF-derived procedures such as oocyte or embryo donation, surrogate mother. The transfer of frozen-thawed embryos increases the total ongoing pregnancy rate per cycle of 31%. One of the aims of our Centre in the near future is the development of new technologies such as control of chromosomal abnormalities or genetic defect in preimplantation embryos and clinical applications of oocyte or ovarian tissue freezing.

Belgium↗
PubMed1999

Laser-assisted myringotomy combined with adenoidectomy in children: preliminary results.

Adenoidectomy and CO2 laser-assisted myringotomy were performed on 26 children (52 ears) diagnosed with adenoid hypertrophy and chronic otitis media with effusion. The age ranged between 2-15. The CO2 laser and a micromanipulator were adapted on the operating microscope. Repeated pulses of focused laser beam were fired in a roselike fashion in order to create a 2-mm round perforation in the antero-inferior quadrant of the eardrum. Three months after surgery, the tympanic membrane was perfectly healed. There were two cases of recurrence of middle ear fluid. There was no adverse effect and hearing results were good. We discuss the significance of these preliminary results and emphasize the need for further research.

Adenoidectomy↗
PubMed1999

The micrometric multiarray technique for percutaneous thermocoagulation of trigeminal neuralgia. Preliminary report.

This report describes the technical features and preliminary results of a multiple electrode array system designed to provide access to four different sites within one or more selected trigeminal divisions. At each segment, multiple clinical sensory and motor data are correlated with radiological landmarks in the individual patient with trigeminal neuralgia. The system consists of an outer needle, through which a multielectrode array is introduced. Four successive 2.9 mm caps at the distal end of the multielectrode protrude from the tip of the outer needle into the cerebrospinal fluid of the post-gasserian fibers. The outer needle is always introduced fluoroscopically or tomographically into the inner third of the oval foramen. No blind punctures or suboptimal positions are accepted. After correlating clinical verbal and motor responses at each cap and inter se, the safest location is selected, with a precise knowledge of the segment of the division lying in front and behind the target. Lesions in the first division, the motor division, and segments not involved with pain are avoided. A thermocouple fitted with a micromanipulator allows the placement of the active tip at the center of the chosen target. The maximal size of the lesion cannot exceed the size of the target. Data from 117 consecutive procedures were systematically recorded in a computerized protocol for future analysis. Corneal anesthesia and deafferentation pain were not observed in this series. Preliminary data suggests that the micrometric technique may significantly minimize the residual morbidity from percutaneous thermocoagulation of trigeminal neuralgia.

Anesthesia, Local↗