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Biomedical subjects

A Bonk

Publications and source records attributed to A Bonk.

9 recordsLinked to original sources
PubMed2004

Effects of different artificial insemination techniques and sperm doses on fertility of normal mares and mares with abnormal reproductive history.

The effects of different artificial insemination (AI) techniques and sperm doses on pregnancy rates of normal Hanoverian breed mares and mares with a history of barrenness or pregnancy failure using fresh or frozen-thawed sperm were investigated. The material included 187 normal mares (148 foaling and 39 young maiden mares) and 85 problem mares with abnormal reproductive history. Mares were randomly allotted into groups with respect to AI technique (routine AI into the uterine body, transrectally controlled deep intracornual AI ipsilateral to the preovulatory follicle, or hysteroscopic AI onto the uterotubal junction ipsilateral to the preovulatory follicle), storage method of semen (fresh, frozen-thawed), AI volume (0.5, 2, 12 ml), and sperm dose (50 x 10(6) or 300 x 10(6) progressively motile sperm (pms) for fresh semen and 100 or 800 x 10(6) frozen-thawed sperm with >35% post-thaw motility). The mares were inseminated once per cycle, 24 h after hCG administration when fresh semen was used, or 30 h for frozen-thawed semen. Differences in pregnancy rates between treatment groups were analyzed by Chi-squared test, and for most relevant factors (insemination technique, mare, semen, and stallion) expectation values and confidence intervals were calculated using multivariate logistic models. Neither insemination technique, volume, sperm dose, nor mare or stallion had significant effects (P > 0.05) on fertility. Type of semen, breeding mares during foal heat, and an interaction between insemination technique, semen parameters, and mares did have significant effects (P < 0.05). In problem mares, frozen semen AI yielded significantly lower pregnancy rates than fresh semen AI (16/43, 37.2% versus 25/42, 59.5%), but this was not the case in normal mares. In normal mares, hysteroscopic AI with fresh semen gave significantly (P < 0.05) better pregnancy rates than uterine body AI (27/38, 71% versus 18/38, 47.3%), whereas in problem mares this resulted in significantly lower pregnancy rates than uterine body AI (5/15, 33.3% versus 16/19, 84.2%). Our results demonstrate that for problem mares, conventional insemination into the uterine body appears to be superior to hysteroscopic insemination and in normal mares, the highest pregnancy rates can be expected by hysteroscopic insemination.

Animals↗
PubMed2001

Cytoplasmic changes in relation to nuclear maturation and early embryo developmental potential of porcine oocytes: effects of gonadotropins, cumulus cells, follicular size, and protein synthesis inhibition.

Morphological and biochemical changes indicative of cytoplasmic maturation in relation to nuclear maturation progression and early embryo developmental potential was studied. Fluorescently labeled microfilaments and cortical granules were visualized by using laser scanning confocal microscopy. The mitogen-activated protein (MAP) kinase phosphorylation and cyclin B1 levels were revealed by Western blot. With the maturation of oocytes, cortical granules and microfilaments were localized at the cell cortex. A cortical granule-free domain (CGFD) and an actin-thickening area were observed over both the MII spindle of a mature oocyte and chromosomes of a nocodazole-treated oocyte, suggesting that chromosomes, but not the spindle, determined the localization of CGFD and actin-thickening area. In oocytes that are incompetent to resume meiosis, as indicated by the failure of germinal vesicle breakdown (GVBD), peripheral localization of cortical granules and microfilaments, phosphorylation of MAP kinase and synthesis of cyclin B1 did not occur after 44 hr in vitro. These cytoplasmic changes were also blocked when GVBD of meiotically competent oocytes was inhibited by cycloheximide. Culture of oocytes in a chemically defined medium showed that biological factors such as gonadotropins, cumulus cells and follicle size affected both nuclear and cytoplasmic maturation as well as embryo developmental potential. Absence of gonadotropins or removal of cumulus cells alone did not significantly influence GVBD or cyclin B1 levels, but decreased the final maturation and developmental ability of oocytes. A combination of gonadotropin absence and cumulus removal decreased GVBD, MAP kinase phosphorylation and embryo development. A high proportion of oocytes derived from small follicles were able to resume meiosis, synthesize cyclin B(1), phosphorylate MAP kinase and translocate CGs, but their maturation and embryo developmental ability were limited. Removal of cumulus cells from small follicle-derived oocytes severely affected their ability to undergo cytoplasmic and nuclear maturation.

Actin Cytoskeleton↗
PubMed2001

Production of nuclear transfer-derived swine that express the enhanced green fluorescent protein.

The ability to add or delete specific genes in swine will likely provide considerable benefits not just to agriculture but also to medicine, where pigs have potential as models for human disease and as organ donors. Here we have transferred nuclei from a genetically modified fibroblast cell line to porcine oocytes, matured in vitro under defined culture conditions, to create piglets expressing enhanced green fluorescent protein. The nuclear transfer-derived piglets were of normal size, although some mild symptoms of "large offspring syndrome" were evident. These experiments represent a next step towards creating swine with more useful genetic modifications.

Agriculture↗
PubMed1994

[Acute injury to the lateral ligament of the ankle joint in the athlete].

The ankle sprain is one of the most common injuries in sports. It is useful to classify the grade of injury clinically. Stress x-rays, stress ultrasound or radiographic examinations are not necessary. Based on the analysis of 24 controlled studies we conclude that functional treatment is sufficient. It does not lead to higher subjective or objective instability nor to a greater number of reinjuries. Functional treatment has no complications. Although controlled studies about the treatment of athletes are missing, but there is no reason for a different treatment in athletes.

Adolescent↗
PubMed1994

[Mechanical dynamic ankle passive motion for physical prevention of thrombosis? Changes in hemodynamics in the lower pressure system with new dynamic splints].

The use of mechanical ankle exercise devices with continuous passive motion (CPM) of the ankle joint can improve venous reflow in the lower limbs after operations. Duplex ultrasonography allows the observations of blood flow velocity and flow volume during continuous movement of the devices. We tested two different CPM devices for ankle movement in a preclinical study on 10 healthy, uninjured people and saw the following changes in the deep venous system in the common femoral vein: after 5 min of motion the velocity of the venous reflow was increased to 112.5% and the flow volume passing the femoral vein to 123% of the initial mean values. After 15 min of motion the devices led to an increase of the venous reflow velocity to 125% and of flow volume to 143% of the baseline values in the femoral vein. These positive effects were still evident even 15 min after the devices have been turned off.

Adult↗
PubMed1981

Immunohistological analysis of Hodgkin's and Sternberg-reed cells: detection of a new antigen and evidence for selective IgG uptake in the absence of B cell, T cell and histiocytic markers.

To help clarify the origin and nature of Hodgkin's (H) and Sternberg-Reed (SR) cells, three different sets of experiments were performed. First, it was shown that cytoplasmic gamma, kappa, lambda occur not only in H and SR cells, but also in polymorphic tumor cells of epithelial, neurogenic, and lymphoid origin. Furthermore, human IgG that was injected i.v. into rats penetrated many rat liver cells, whereas injected human alpha 1-antitrypsin did not. Second, staining of frozen sections revealed that H and SR cells lack surface immunoglobulin and peripheral T-cell antigen. Third, an antiserum raised against the L 428 cell line (derived from Hodgkin's disease) and absorbed with human serum and normal cells did not react with any cells of tonsil tissue (lymphoid cells, histiocytes, and interdigitating reticulum cells), whereas it reacted strongly with the L 428 cell line cells and with H and SR cells of 10 different cases. In all ten cases, the antiserum stained the surface of H and SR cells; in two cases, it also stained the nucleoli and some chromatin spots in H and SR cells. The results obtained in these experiments indicate that H and SR cells are not closely related to lymphoid cells, histiocytes, or interdigitating reticulum cells. The findings also suggest that H and SR cells express one or more antigens that have not yet been detected on or in normal cells.

Animals↗
PubMed1980

Immunohistologic analysis of the organization of normal lymphoid tissue and non-Hodgkin's lymphomas.

Hoping to improve the systems for identifying and classifying normal and malignant lymphoid subpopulations, frozen and paraffin sections of nonmalignant lymphoid tissue and of malignant lymphomas were immunostained for surface (S) and cytoplasmic antigens using the peroxidase-antiperoxidase method. Primary follicle cells and follicle mantle cells known to be part of the recirculating B-cell pool were found to be constantly Ia and C3 receptor (C3R) positive, mostly SIgM and SIgD positive and cytoplasmic immunoglobulin (CIg) negative. The light zone of germinal centers (GC), which is rich in centrocytes, contained a large number of T cells and showed the well-known intercellular Ig network pattern; the dark zone, containing densely packed centroblasts, was usually free of T cells, but was bordered ay a mantle-like accumulation of T cells. Usually only some of the GC cells were definitely positive for SIg and CIg of different classes. All cells reacted positively for Ia and C3R. In areas described by other authors as containing marginal zone cells, cells densely bearing SIgM and deficient in SIgD were detected. The immunoblasts of the hyperplastic plasma cell reaction usually contained CIg. Cells from chronic lymphoid leukemia sections that immunostained for SIgM and SIgD were interpreted as representing a neoplasm of recirculating B cells expressing SIgM and SIgD. The immunohistologic architecture of follicular centroblastic/centrocytic lymphoma showed a more or less close similarity to the organization of secondary follicles. Lymphomas whose cells resembled reactive centrocytes were strongly SIgM positive and SIgD negative or only weakly SIgD positive. CIg was demonstrable in nearly 90% of the lymphomas whose cells resembled centroblasts and in 70% of the lymphomas whose cells resembled immunoblasts of the plasma cell reaction. Finally, immunohistologic staining results from a T-zone lymphoma are presented, which confirm that this lymphoma was composed of a neoplastic T zone and a non-malignant B zone.

Antigens↗