Genetic parameters for bull effects on in vitro embryo production (IVP) and relationship between semen quality traits and IVP performance.

In vitro production of embryos (IVP) is increasingly applied in dairy cattle breeding and promises widespread use of females of superior genetic merits. One of the current challenges with implementation of IVP is the variability in blastocyst rates. Several factors contribute to these variabilities, among which is known to be the bull used for oocytes fertilization.

Identification of sperm proteins as biomarkers of field fertility in Holstein-Friesian bulls used for artificial insemination.

Despite passing stringent quality control, bulls used in artificial insemination can vary significantly in their fertility, emphasizing the need for reliable markers of sperm quality. This study aimed to identify sperm proteins acting as biomarkers of fertility in 2 different populations of dairy bulls classified based on their field fertility. Semen was collected and cryopreserved from: 54 Holstein bulls located in Ireland, classified according to fertility indexes as low fertility (LF, n = 23), medium fertility (n = 14), or high fertility (HF, n = 17); and 18 Holstein bulls located in Denmark, classified as LF (n = 8) or HF (n = 10).

The effect of adjusting settings within a Computer-Assisted Sperm Analysis (CASA) system on bovine sperm motility and morphology results.

Semen motility is the most widely recognized semen quality parameter used by Artificial Insemination (AI) centers. With the increasing worldwide export of semen between AI centers there is an increasing need for standardized motility assessment methods. Computer-Assisted Sperm Analysis (CASA) technology is thought to provide an objective motility evaluation; however, results can still vary between laboratories.

Comprehensive functional analysis reveals that acrosome integrity and viability are key variables distinguishing artificial insemination bulls of varying fertility.

In vitro methods of assessing bull semen quality in artificial insemination (AI) centers are unable to consistently detect individuals of lower fertility, and attempts to reliably predict bull fertility are still ongoing. This highlights the need to identify robust biomarkers that can be readily measured in a practical setting and used to improve current predictions of bull fertility. In this study, we comprehensively analyzed a range of functional, morphological, and intracellular attributes in cryopreserved spermatozoa from a selected cohort of Holstein Friesian AI bulls classified as having either high or low fertility (n = 10 of each fertility phenotype; difference of 11.

Genetic parameters of semen quality traits and genetic correlations with service sire nonreturn rate in Nordic Holstein bulls.

Despite the importance of the quality of semen used in artificial insemination to the reproductive success of dairy herds, few studies have estimated the extent of genetic variability in semen quality traits. Even fewer studies have quantified the correlation between semen quality traits and male fertility. In this study, records of 100,058 ejaculates collected from 2,885 Nordic Holstein bulls were used to estimate genetic parameters for semen quality traits, including pre- and postcryopreservation semen concentration, sperm motility and viability, ejaculate volume, and number of doses per ejaculate.

Effect of freezing bull semen in two non-egg yolk extenders on post-thaw sperm quality.

Traditionally, extenders for bull semen included egg yolk or milk, but recently there has been a move to avoid material of animal origin. The aim of this study was to evaluate the effects of two commercial extenders (based on soya lecithin and liposomes) on bull sperm quality after cryopreservation. Post-thaw sperm quality was evaluated by computer-assisted sperm analysis and flow cytometric assessment of membrane integrity, chromatin integrity, mitochondrial membrane potential, production of reactive oxygen species and tyrosine phosphorylation.

Biological aspects of altered bone remodeling in multiple myeloma and possibilities of pharmacological intervention.

Multiple myeloma is a fatal B cell neoplasm often resulting in focal and in some cases more diffuse destruction of bone. The bone destruction is a result of increased activity of bone resorbing cells--multinucleated osteoclasts emerging through of multiple fusions. In multiple myeloma, clonally expanding cancer cells provide a stimulatory signal for osteoclast recruitment, differentiation and excessive bone resorption.

Potential of resveratrol analogues as antagonists of osteoclasts and promoters of osteoblasts.

The plant phytoalexin resveratrol was previously demonstrated to inhibit the differentiation and bone resorbing activity of osteoclasts, to promote the formation of osteoblasts from mesenchymal precursors in cultures, and inhibit myeloma cell proliferation, when used at high concentrations. In the current study, we screened five structurally modified resveratrol analogues for their ability to modify the differentiation of osteoclasts and osteoblasts and proliferation of myeloma cells. Compared to resveratrol, analogues showed an up to 5,000-fold increased potency to inhibit osteoclast differentiation.

Pulse treatment with the proteasome inhibitor bortezomib inhibits osteoclast resorptive activity in clinically relevant conditions.

Myeloma bone disease is due to bone degradation by osteoclasts, and absence of repair by bone forming osteoblasts. Recent observations suggest that the anti-myeloma drug bortezomib, a proteasome inhibitor, stimulates bone formation and may inhibit bone resorption. Here, we tested bortezomib on cultured osteoclasts in conditions mimicking the pulse treatment used in the clinic, thereby avoiding continuous proteasome inhibition and unselective toxicity.

dlk1/FA1 regulates the function of human bone marrow mesenchymal stem cells by modulating gene expression of pro-inflammatory cytokines and immune response-related factors.

dlk1/FA1 (delta-like 1/fetal antigen-1) is a member of the epidermal growth factor-like homeotic protein family whose expression is known to modulate the differentiation signals of mesenchymal and hematopoietic stem cells in bone marrow. We have demonstrated previously that Dlk1 can maintain the human bone marrow mesenchymal stem cells (hMSC) in an undifferentiated state. To identify the molecular mechanisms underlying these effects, we compared the basal gene expression pattern in Dlk1-overexpressing hMSC cells (hMSC-dlk1) versus control hMSC (negative for Dlk1 expression) by using Affymetrix HG-U133A microarrays.

Osteoclast nuclei of myeloma patients show chromosome translocations specific for the myeloma cell clone: a new type of cancer-host partnership?

A major clinical manifestation of bone cancers is bone destruction. It is widely accepted that this destruction is not caused by the malignant cells themselves, but by osteoclasts, multinucleated cells of monocytic origin that are considered to be the only cells able to degrade bone. The present study demonstrates that bone-resorbing osteoclasts from myeloma patients contain nuclei with translocated chromosomes of myeloma B-cell clone origin, in addition to nuclei without these translocations, by using combined FISH and immunohistochemistry on bone sections.