DNA synthesis and epigenetic modification during mouse oocyte fertilization by human or hamster sperm injection

PURPOSE

To evaluate DNA synthesis and epigenetic modification in mouse oocytes during the first cell cycle following the injection of human or hamster sperm.

METHODS

Mouse oocytes following the injection of human and hamster sperm and cultured in M16 medium.

RESULTS

Male and female pronucleus formation, DNA synthesis, histone protein modification, and heterochromatin formation were similar in mouse oocytes injected with human or hamster sperm. However, DNA methylation patterns were altered in mouse oocytes following human sperm injection. Immunocytochemical staining with a histone H3-MeK9 antibody revealed that human and hamster sperm chromatin associated normally with female mouse chromatin, then entered into the metaphase and formed normal, two-cell stage embryos.

CONCLUSIONS

Although differences in epigenetic modification of DNA were observed, fertilization and cleavage occurred in a species non-specific manner in mouse oocytes.

Perturbation of Spc25 expression affects meiotic spindle organization, chromosome alignment and spindle assembly checkpoint in mouse oocytes

Spc25 is a component of the Ndc80 complex which consists of Ndc80, Nuf2, Spc24, and Spc25. Previous work has shown that Spc25 is involved in regulation of kinetochore microtubule attachment and the spindle assembly checkpoint in mitosis. The roles of Spc25 in meiosis remain unknown. Here, we report its expression, localization and functions in mouse oocyte meiosis. The Spc25 mRNA level gradually increased from the GV to MI stage, but decreased by MII during mouse oocyte meiotic maturation. Immunofluorescent staining showed that Spc25 was restricted to the germinal vesicle, and associated with chromosomes during all stages after GVBD. Overexpression of Spc25 by mRNA injection resulted in oocyte meiotic arrest, chromosome misalignment and spindle disruption. Conversely, Spc25 RNAi by siRNA injection resulted in precocious polar body extrusion and caused severe chromosome misalignment and aberrant spindle formation. Our data suggest that Spc25 is required for chromosome alignment, spindle formation, and proper spindle checkpoint signaling during meiosis.

Mitochondrial dysfunction influences apoptosis and autophagy in porcine parthenotes developing in vitro

Mitochondria are important regulators of both apoptosis and autophagy. One of the triggers for mitochondrial-mediated apoptosis is the production of reactive oxygen species (ROS), which include hydrogen peroxide, superoxide, hydroxyl radical, nitric oxide and peroxynitrite. Recently, several studies have indicated that ROS may also be involved in the induction of autophagy. In the present study, we used H(2)O(2) to induce mitochondrial stress, examined apoptotic- and autophagic-related gene expression and observed LC3 protein (autophagosome presence marker) expression in porcine parthenotes developing in vitro. In porcine four-cell parthenotes cultured for 5 days in NCSU37 medium containing 0.4% BSA, the developmental rate and mitochondrial distribution did not differ from that of the group supplemented with 100 µM H(2)O(2) but was significantly decreased in the group supplemented with 500 µM H(2)O(2) (P<0.05). Transmission electron microscopy (TEM) indicated that whereas normal shaped mitochondria were observed in blastocysts from the control group, abnormal mitochondria (mitophagy) and autophagic vacuoles were observed in blastocysts from the group that received 500 µM H(2)O(2). Furthermore, addition of H(2)O(2) (100 µM and 500 µM) decreased cell numbers (P<0.05) and increased both apoptosis (P<0.05) and LC3 protein expression in the blastocysts. Real-time RT-PCR showed that H(2)O(2) significantly decreased mRNA expression of anti-apoptotic gene Bcl-xL but increased pro-apoptotic genes, Caspase 3 (Casp3) and Bak, and autophagy-related genes, microtubule-associated protein 1 light chain 3 (Map1lc3b) and lysosomal-associated membrane protein 2 (Lamp2). However, the addition of H(2)O(2) had no effect on mRNA expression levels in nuclear DNA-encoded mitochondrial-related genes, cytochrome oxidase (Cox) 5a, Cox5b and Cox6b1, in blastocysts. These results suggest that H(2)O(2) leads to mitochondrial dysfunction that results in apoptosis and autophagy, which is possibly related to porcine early embryo development.

Expression of HER-2 and nuclear localization of HER-3 protein in canine mammary tumors: histopathological and immunohistochemical study

HER-2 and HER-3 are transmembrane receptor proteins that are considered to be important but poorly understood biomarkers in canine tumors. In this study, the expression and the localization of HER-2 and HER-3 were evaluated immunohistochemically in canine mammary tumors (n=64; 12 benign, 52 malignant). HER-2 overexpression was identified in 2/12 (16.7%) benign and in 18/51 (35.3%) malignant cases. HER-3 was expressed in a non-nuclear localization in 11/12 (91.7%) benign and 18/52 (34.6%) malignant tumors. In contrast, HER-3 was expressed in the nucleus of neoplastic cells in 0/12 (0%) benign and 22/52 (42.3%) malignant tumors. Nuclear HER-3 expression was higher in neoplastic epithelial cells compared to myoepithelial cells, and positively correlated with high histological grade and lymphatic vessel invasion. These results suggest that nuclear HER-3 expression is significantly associated with tumor progression and metastasis and may serve as a useful prognostic biomarker in canine malignant mammary tumors.

Borealin regulates bipolar spindle formation but may not act as chromosomal passenger during mouse oocyte meiosis

In mitosis, Borealin is a member of the chromosomal passenger complex (CPC), which plays interaction roles with INCENP and survivin in the complex. Its roles in mammalian meiosis are unknown. Here, we report the expression, localization, and function of Borealin and its relation with survivin in mouse oocyte meiosis. Borealin expression was gradually increased from GV stage to MII. Immunofluorescence results revealed that Borealin accumulated near chromosomes after GVBD, localized at the spindle poles in MI, AI and MII, and at the midbody in TI stage. Taxol and nocodazole treatment showed that the localization of Borealin was dependent on microtubule dynamics, whereas survivin was independent of this. Disruption of Borealin function by antibody injection resulted in severe spindle assembly defects, but did not affect PBE. We also found that depletion of survivin by MO injection had no effect on the localization of Borealin. In conclusion, our data suggest that Borealin is required for bipolar spindle formation, but may not regulate spindle checkpoint activity as a component of the CPC during mouse oocyte meiosis.

Molecular characterization of pig alpha2,3-Gal-beta1,3-GalNAc-alpha2,6-sialyltransferase (pST6GalNAc IV) gene specific for Neu5Acalpha2-3Galbeta1-3GalNAc trisaccharide structure

Sialic acids of glycoconjugates play crucial roles in various biological processes, such as cell-cell communication and cell-substrate interaction. A sisalyltransferase, ST6GalNAc IV (Neu5Ac-alpha2,3-Gal-beta1,3-GalNAc-alpha2,6-sialyltransferase), catalyzes the formation of alpha2-6-linkages onto GalNAc residues of O-glycosidically linked Ser/Thr of proteins. In this study, we cloned the pig ST6GalNAc IV (pST6GalNAc IV) and investigated its functional characterization. pST6GalNAc IV cDNA has been isolated from pig liver tissues and it contains an entire open reading frame (ORF, 906 bp) coding for 302 amino acid residues. Entire ORF of pST6GalNAc IV containing sialylmotif 'L'-(Large), 'S'-(Small) and '-VS' (Very small) has a high degree of sequence similarity with Homo sapiens (90%), Pan troglodytes (91%) and Mus musculus (87%). Expression of pST6GalNAc IV mRNA in various pig tissues was identified by reverse transcription polymerase chain reaction (RT-PCR) analysis. pST6GalNAc IV mRNA was highly expressed in tongue, muscle and heart, whereas it was not expressed in pancreas. For functional characterization of pST6GalNAc IV gene in pig kidney PK15 cells, we have also established pST6GalNAc IV-transfected PK15 cells, which are stably expressing the pST6GalNAc IV gene. The glycosylation pattern of pST6GalNAc IV-transfected PK15 cells was detected by flow cytometry and immunofluorescence analysis with Maackia amurensis agglutinin (MAA), Maackia amurensis hemagglutinin (MAL II), Sambucus nigra agglutinin (SNA) and peanut agglutinin (PNA) lectins. The specific carbohydrate structures of Neu5Acalpha2-3Galbeta1-3(Neu5Acalpha2-6)GalNAc tetrasaccharide or Neu5Acalpha2-6GalNAc disaccharide recognized by MAL-II and SNA were revealed to be newly synthesized by pST6GalNAc IV. From the results, it was suggested that the pig pST6GalNAc IV gene is capable of synthesizing Neu5Acalpha2-3Galbeta1-3(Neu5Acalpha2-6)GalNAc tetrasaccharide structures on O-glycoproteins.

Role of CK1 in GSK3beta-mediated phosphorylation and degradation of snail

The epithelial to mesenchymal transition (EMT) that occurs during embryonic development has begun to attract attention as a potential mechanism for tumor cell metastasis. Snail is a well-known Zn-finger transcription factor that promotes EMT by repressing E-cadherin expression. It is known that Snail is phosphorylated by GSK3beta and degraded by beta-TrCP-mediated ubiquitination. Here we described another protein kinase, CK1, whose phosphorylation of Snail is required for the subsequent GSK3beta phosphorylation. Specific inhibition or depletion of CK1varepsilon inhibits the phosphorylation and degradation of Snail and promotes cell migration, suggesting a central role of CK1varepsilon in the EMT process. Furthermore, our study uncovered distinct roles and steps of Snail phosphorylation by CK1varepsilon and GSK3beta. Taken together, we identified CK1varepsilon as a new component of the Snail-mediated EMT process, providing insight into the mechanism of human cancer metastasis.

Molecular characterization and polyadenylation-regulated expression of cyclin B1 and Cdc2 in porcine oocytes and early parthenotes

Meiotic maturation of mammalian oocytes is controlled by the maturation/M-phase promotion factor (MPF), a complex of Cdc2 kinase and cyclin B protein. To better understand the molecular mechanism of oocyte maturation, we characterized porcine cyclin B1 and Cdc2 genes, both of which are widely expressed in pig tissues. We further analyzed their expression profiles during in vitro maturation of pig oocyte and early embryonic development at both the mRNA and protein level. Two isoforms of cyclin B1, comprising the same open reading frame but differing in 3'-UTR length, were identified. Cyclin B1 transcripts was up-regulated after 30 hr of maturation, while Cdc2 mRNA levels were unchanged during maturation except for a sharp decline at 44 hr. Cyclin B1 protein synthesis increased with oocyte maturation. Cdc2 protein expression was relatively low during 0-18 hr, followed by a higher level of expression up to 44 hr of maturation. Poly(A)-test PCR clearly revealed that both cyclin B1 isoforms underwent cytoplasmic polyadenylation starting around 18-24 hr during maturation, while a substantial de-adenylation and degradation of Cdc2 isoforms were observed in metaphase II oocytes and during embryo development after parthenogenetic activation. Porcine MII oocytes derived from small follicles (< or = 3 mm) and bad quality 2-cell parthenotes showed lower developmental competence and lower levels of cyclin B1 protein, and Cdc2 mRNA or both gene mRNAs, respectively, compared to their control counterparts. These results suggested that cyclin B1 was regulated posttranscriptionally by cytoplasmic polyadenylation during porcine oocyte maturation. Further, the decreased expression of maternal cyclin B1 and Cdc2 at the mRNA or protein level in developmentally incompetent oocytes and embryos was responsible for, at least in part, a profound defect in further embryonic development.

Ago2 and GW182 expression in mouse preimplantation embryos: a link between microRNA biogenesis and GW182 protein synthesis

MicroRNA-mediated RNA interference appears to play a role in early development and differentiation processes in preimplantation embryos. However, the expression of its key effectors, including Ago2, a key component of the RNA-induced silencing complex, and GW182, a critical component of GW bodies (GWBs), has not been assessed in preimplantation embryos. To characterise the roles of Ago2 and GW182 in early embryo development, we determined their transcription and protein synthesis in mouse embryos. Transcript levels of Ago2 and GW182 increased steadily from the one-cell stage through to the blastocyst stage when data were not normalised against an internal reference. However, when normalised against the internal standard, transcript levels for both genes were highest in four-cell stage embryos and decreased steadily through to the blastocyst stage. Indirect immunocytochemistry showed that both AGO2 and GW182 proteins were expressed in each stage in the early embryo and were observed to colocalise in the morula and blastocyst stages. Specific silencing of mRNA expression by short interference (si) RNA against Ago2 or Dicer1 decreased the expression of selected apoptosis- and development-related microRNAs, but did not inhibit development up to the blastocyst stage. However, transcription levels of Oct3/4, Nanog and Sox2 were decreased in both Ago2- and Dicer1-knockdown embryos at the blastocyst stage. Furthermore, although knockdown of these genes did not change transcript levels of GW182, GW182 protein synthesis was decreased in blastocyst stage embryos. These results suggest that Ago2 and Dicer1 regulate GW182 protein expression in mouse embryos, which is linked to microRNA biogenesis and likely to be important for differentiation in the blastocyst stage.

A link between the interleukin-6/Stat3 anti-apoptotic pathway and microRNA-21 in preimplantation mouse embryos

Signal transducers and activators of transcription-3 (Stat3) plays a central role in interleukin-6 (IL-6)-mediated cell proliferation by inhibiting apoptosis in a variety of cell types. MicroRNA-21 (miRNA-21), a ubiquitous miRNA, acts as an anti-apoptotic factor that seems to be indirectly but strictly linked to Stat3. In order to determine whether the IL-6 induced Stat3 anti-apoptosis pathway is linked with miRNA-21, we first determined the effects of recombinant mouse IL-6 on Stat3 expression, mouse embryo viability, and the mRNA levels of apoptosis related genes and miRNA-21 during mouse embryo development in vitro. Addition of 10 or 100 ng/ml of recombinant IL-6 to the culture medium did not affect the developmental ability of 2-cell stage embryos into blastocysts. However, total cell number was significantly increased and apoptosis was reduced in blastocyst stage embryos cultured in the presence of 100 ng/ml of recombinant IL-6. Furthermore, addition of recombinant IL-6 to the culture medium significantly increased the copy numbers of anti-apoptotic miRNA-21, up-regulated Bcl2l1, and down-regulated casp3. Similarly, the injection of mature miRNA-21 into cells up-regulated Bcl2l1 and down-regulated casp3. These results suggest that the induction of the Stat3 anti-apoptotic pathway by IL-6 is linked to miRNA-21 expression, which possibly results in the regulation of cell apoptosis in early mouse embryo development.

Perturbation of survivin expression affects chromosome alignment and spindle checkpoint in mouse oocyte meiotic maturation

Survivin is a member of inhibitors of apoptosis proteins (IAPs), which have multiple regulatory functions in mitosis, but its roles in meiosis remain unknown. Here, we report its expression, localization and functions in mouse oocyte meiosis. Survivin displayed a maximal expression level in GV stage, and then gradually decreased from Pro-MI to MII stages. Immunofluorescent staining showed that survivin was restricted to the germinal vesicle, associated with centromeres from pro-metaphase I to metaphase I stages, distributed at the midzone and midbody of anaphase and telophase spindles, and located to centromeres at metaphase II stages. Depletion of survivin by antibody injection and morpholino injection resulted in severe chromosome misalignment, precocious polar body extrusion, and larger-than-normal polar bodies. Overexpression of survivin resulted in severe chromosome misalignment and prometaphase I or metaphase I arrest in a large proportion of oocytes. Our data suggest that survivin is required for chromosome alignment and that it may regulate spindle checkpoint activity during mouse oocyte meiosis.

Involvement of polyadenylation status on maternal gene expression during in vitro maturation of porcine oocytes

During mammalian oocyte maturation, protein synthesis is mainly controlled through cytoplasmic polyadenylation of stored maternal mRNAs. In this study, the role of polyadenylation modification of maternal transcripts in pig oocytes was investigated by adding cordycepin (3'-dA), a potent polyadenylation inhibitor, to the culture medium of porcine oocytes maturing in vitro. 3'-dA significantly prevented cumulus expansion regardless of the concentration used, and inhibited pig oocyte maturation in a dose-dependent manner. Further, 3'-dA 1 microg/ml-treated MII oocytes experienced significantly lower rates of cleavage (29%) and blastocyst formation (15.35%) compared to control MII oocytes (58.6% and 35.3%, respectively). Western blotting revealed that the activity of mitogen-activated protein kinase (MAPK) and p34(cdc2) was significantly decreased in oocytes and cumulus cells treated with 3'-dA at a concentration of 1 microg/ml or greater. To further explore the underlying molecular mechanisms, expression patterns and polyadenylation states of four important genes, C-mos, cyclin B, GDF9 and BMP15, were studied as representative maternal transcripts by real-time PCR and the PAT assay. 3'-dA at concentrations above 1 microg/ml significantly prevented polyadenylation and caused aberrant expression of C-mos and GDF9 during oocyte maturation. These results suggest that polyadenylation inhibitor blocked pig oocyte maturation in vitro by one or more of the following actions: (1) inactivation of MAPK and MPF in oocytes, especially at the late stages (MI and MII); (2) prevention of cumulus cell expansion through inactivation of cellular MAPK; and (3) inhibition of the maternal mRNA polyadenylation process, which in reverse, disrupted the maternal mRNA patterns in pig oocytes' maturation in vitro.

Tetracycline-dependent expression of the human erythropoietin gene in transgenic chickens

A critical problem in the production of transgenic animals is the uncontrolled constitutive expression of the foreign gene, which occasionally results in serious physiological disorders in the transgenic animal. In this study, we report successful production of transgenic chickens that express the human erythropoietin (hEPO) gene under the control of a tetracycline-inducible promoter. A recombinant Moloney murine leukemia virus (MoMLV)-based retrovirus vector encapsidated with vesicular stomatitis virus G glycoprotein (VSV-G) was injected beneath the blastoderm of unincubated chicken embryos (stage X). Out of 198 injected eggs, 15 chicks hatched after 21 days of incubation and 14 hatched chicks expressed the vector-encoded hEPO gene when fed doxycycline, a tetracycline derivative, without any significant physiological dysfunctions. The expression of hEPO reverted to the pre-induction state by removing doxycycline from the diet. The biological activity of the hEPO produced in the transgenic chickens was comparable to commercially available CHO cell-derived hEPO. Successful germline transmission of the transgene was also confirmed in G1 transgenic chicks produced from crossing G0 transgenic roosters with non-transgenic hens. Tetracycline-inducible expression of the hEPO gene was also confirmed in the blood and eggs of the transgenic chickens.

Hyperglycemia reduces mitochondrial content and glucose transporter expression in mouse embryos developing in vitro

The objective of this research was to examine the effects of high concentrations of glucose on mouse embryos developing in vitro by studying embryo viability, mitochondrial content and expression of glucose transporters. Addition of 55 mM glucose to the culture medium of two-cell stage embryos significantly reduced the formation of morulae and blastocysts, resulting in fewer cells in the blastocyst stage embryos and increased levels of apoptosis. Quantitative reverse transcriptase (RT) PCR analysis revealed that the expression levels of the pro-apoptotic genes Bax and Casp3 at the blastocyst stage were increased significantly by the addition of either 25 or 55 mM glucose to the culture medium. However, addition of 25 or 55 mM glucose to the culture medium did not change the copy numbers of the apoptosis-related miRNAs mmu-mir-15a, mmu-mir-16 and mmu-mir-21. MitoTracker Green fluorescence revealed a decrease in the mitochondrial mass. The expression levels of the mitochondrial DNA-encoded genes Cox1 and Cox2 decreased sharply with the addition of 25 or 55 mM glucose to the culture medium. Both transcripts and protein synthesis of the glucose transporters Glut1 and Glut3 were reduced in blastocysts cultured in the presence of either 25 or 55 mM glucose. These results suggest that hyperglycemia reduces both mitochondrial content and expression levels of glucose transporters in mouse embryos developing in vitro and that this may result in apoptosis in these embryos.

High mobility group box 1 (HMGB1) is implicated in preimplantation embryo development in the mouse

High mobility group box 1 (HMGB1) regulates multiple cell functions, including transcription, DNA repair, differentiation, and apoptosis. In order to obtain insight into the role of HMGB1 in embryo development, we first evaluated its gene expression levels in mouse preimplantation embryos. Quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) revealed high expression levels in zygotes, and expression steadily increased after zygotic genome activation when normalized to the rabbit Globin mRNA. Indirect immunocytochemistry showed that the HMGB1 protein was also produced in mouse embryos. Injection of a small interfering RNA (siRNA) specific for HMGB1 into zygotes specifically reduced both mRNA expression (P < 0.001) and protein synthesis of HMGB1 in early embryos developed in vitro. Injection of siRNA into the zygote did not affect development to the blastocyst stage, but significantly decreased cell numbers (P < 0.01) in the blastocyst and increased caspase3 (Casp3, P < 0.05) gene expression and apoptosis (P < 0.005). Addition of recombinant HMGB1 (Sigma, H-4652) into the culture medium enhanced the development of zygote stage mouse embryos to blastocysts, in the absence of BSA supplementation. These findings suggest that endogenous and exogenous HMGB1 are implicated in preimplantation embryo development in the mouse.

Auranofin promotes retinoic acid- or dihydroxyvitamin D3-mediated cell differentiation of promyelocytic leukaemia cells by increasing histone acetylation

BACKGROUND AND PURPOSE

To investigate the molecular mechanism for the effect of auranofin on the induction of cell differentiation, the cellular events associated with differentiation were analysed in acute promyelocytic leukaemia (APL) cells.

EXPERIMENTAL APPROACH

The APL blasts from leukaemia patients and NB4 cells were cotreated with auroanofin and all-trans-retinoic acid (ATRA) at suboptimal concentration. The HL-60 cells were treated with auroanofin and a subeffective dose of 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2 vit D3) in combination. The effect of auroanofin was investigated on histone acetylation at the promoter of differentiation-associated genes and expression of cell cycle regulators.

KEY RESULTS

Treatment with auroanofin and ATRA cooperatively induced granulocytic differentiation of fresh APL blasts isolated from patients and NB4 cells. The combined treatment also increased reorganization of nuclear PML bodies and histone acetylation at the promoter of the RARbeta2 gene. Auroanofin also promoted monocytic differentiation of the HL-60 cells triggered by subeffective concentration of 1,25(OH)2 vit D3. The combined treatment of auroanofin and 1,25(OH)2 vit D3 stimulated histone acetylation at p21 promoters and increased the accumulation of cells in the G0/G1 phase. Consistent with this, the expressions of p21, p27 and PTEN were increased and the levels of cyclin A, Cdk2 and Cdk4 were decreased. Furthermore, the hypophosphorylated form of pRb was markedly increased in cotreated cells.

CONCLUSIONS AND IMPLICATIONS

These findings indicate that auroanofin in combination with low doses of either ATRA or 1,25(OH)2 vit D3 promotes APL cell differentiation by enhancing histone acetylation and the expression of differentiation-associated genes.

Serum retinol-binding protein 4 levels are elevated in non-alcoholic fatty liver disease

OBJECTIVE

Retinol-binding protein 4 (RBP4) is a recently identified adipokine that is elevated in the serum in several insulin-resistant states. We investigated the relationship between non-alcoholic fatty liver disease (NAFLD) and serum RBP4 in nondiabetic adults.

METHODS

One hundred and fifty-nine nondiabetic, non-alcoholic subjects (95 males and 64 females) participated in this study. Division of subjects into a NAFLD group (n = 73; 45 males and 28 females) or a normal group (n = 86; 50 males and 36 females) was based on the presence of fatty liver disease determined by sonography.

RESULTS

Serum RBP4 levels in the NAFLD group were significantly higher than those in the normal group (62.8 +/- 16.0 mg/l vs. 51.7 +/- 14.6 mg/l, P < 0.0001). Multiple logistic regression analysis revealed that the RBP4 level was an independent factor associated with NAFLD (P = 0.0042). In addition, serum RBP4 levels were positively correlated with serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltranspeptidase (GGT) levels. The significant association between serum RBP4 and GGT levels remained even after adjusting for age, gender, body mass index, the homeostasis model of assessment (HOMA) value and the presence of NAFLD (r = 0.3097, P = 0.0002).

CONCLUSION

Serum RBP4 levels are significantly associated with NAFLD and liver enzymes.

Respiratory rate detection algorithms by photoplethysmography signal processing

Photoplethysmography (PPG) offers the clinically meaningful parameters, such as, heart rate, and respiratory rate. In this study, we presented three respiratory signal detection algorithms using photoplethysmography raw data generated from commercial PPG sensor: (1)Min-Max (2)Peak-to-Peak (3)Pulse Shape. As reference signal, nasal sensor signal was acquired simultaneously and compared and analyzed. We used two types of moving average filtering technique to process three PPG parameters. In laboratory experiment, 6 subjects' PPG signals were measured when they respire ten and fifteen, and arbitrary times per minute. From the results, following conclusions were drawn. Min-Max and Peak-to-Peak algorithms perform better than Pulse shape algorithm. They can be used to detect respiratory rate. But, Pulse Shape algorithm was accurate for subject 4 only. More experimental data is necessary to improve the accuracy and reliability.

Porcine embryos produced after intracytoplasmic sperm injection using xenogeneic pig sperm from neonatal testis tissue grafted in mice

Embryo development after homologous intracytoplasmic sperm injection (ICSI) with sperm from testis tissue xenografts from pigs or any other farm animal species has not been evaluated critically. Here, we report development of porcine embryos in vitro following ICSI with sperm retrieved from xenografted neonatal pig testis. Small pieces of testis tissue from newborn piglets were grafted under the back skin of castrated immunodeficient mice (n = 4) and the xenografts were collected 8 months after grafting. Spermatozoa were recovered by mincing of the grafted tissue. For comparison, testicular, epididymal and ejaculated spermatozoa were also collected from mature boars. Oocytes injected with xenogeneic spermatozoa were either fixed to determine fertilisation processes (n = 89 in five replicates) or allowed to develop in vitro (n = 143 in four replicates). Xenogeneic porcine spermatozoa were fertilisation competent (24% v. 58%, 68%, 62% or 0% for xenogeneic v. control testicular, epididymal and ejaculated spermatozoa or no spermatozoa, respectively) and embryos developed to the blastocyst stage (8% v. 22%, 27%, 25% or 0%, respectively). These results demonstrate that porcine spermatozoa derived from immature testis tissue xenografted into mice are fertilisation competent, albeit at a lower rate than testicular, epididymal or ejaculated spermatozoa from control boars, and support embryo development after ICSI.

Germinal vesicle chromatin configuration and meiotic competence is related to the oocyte source in canine

This study investigated the effect of deriving oocytes from different stages of the estrous cycle on oocyte diameter, germinal vesicle (GV) chromatin configuration, and in vitro meiotic competence in canine oocytes. Cumulus oocyte complexes (COCs) were recovered from both ovaries during anestrous, follicular, and luteal phases and in vivo ovulated oocytes. The diameter of canine oocyte was compared with or without the zona pellucida (ZP) before in vitro maturation (IVM). Also, GV chromatin configuration was evaluated before (0 h) or 72 h after IVM by fixation with 3.7% formaldehyde supplemented with 10 microg/ml Hoechst 33342 for 30 min. COCs were matured in TCM199 supplemented with 10% fetal bovine serum (FBS), 0.6 mM cysteine, 0.2 mM pyruvic acid, 50 microg/ml gentamycin sulfate, and 20 microg/ml 17beta-estradiol (E(2)) at 39 degrees C and 5% CO(2) in air for 72 h. The diameter of in vivo ovulated oocytes with the ZP (167.5+/-12.7 microm) or without ZP (133.9+/-5.3 microm) was significantly greater (p<0.05) than those of anestrous, follicular, and luteal oocytes (with ZP, 151.2+/-7.4, 153.1+/-8.8 and 152.8+/-5.4 microm, respectively; without ZP, 115.3+/-7.6, 122.1+/-4.9 and 114.3+/-6.6 microm, respectively). At 0 h, the GV-II configuration was more prevalent in oocytes from anestrual ovaries than from follicular or luteal ovaries or in vivo ovulated oocytes (63.6% versus 14.8%, 33.0%, and 0.0%; p<0.05), whereas the proportion of oocytes with the GV-V configuration was higher in follicular phase and ovulated oocytes than in oocytes from anestrus and luteal phase (57.4% and 100% versus 2.0% and 22.7%; p<0.05). However, oocytes in luteal phase exhibited diverse GV configurations (10.3%, 33.0%, 16.5%, 13.4%, and 22.7% in GV-I, GV-II, GV-III, GV-IV, and GV-V, respectively). After 72 h post-IVM, a greater percentage of in vivo ovulated oocytes progressed to MII than those oocytes collected during anestrous, follicular, and luteal phases (50.0% versus 5.5%, 11.5%, and 9.1%; p<0.05). In conclusion, the oocyte diameter, GV chromatin configuration, and meiotic maturation of canine COCs are related to the oocyte source. These results indicated that the oocyte source could be critical to nuclear progression to MII stage in canines.