Gene expression and localization of 20α-hydroxysteroid dehydrogenase (HSD) in reproductive tissues during early pregnancy of cattle

The enzyme 20α-hydroxysteroid dehydrogenase (20α-HSD) catalyzes the conversion of progesterone to its inactive form, 20α-hydroxyprogesterone, and this enzyme has an important role in the regulation of luteal function in mammals. It has previously been determined that the 20α-HSD gene is primarily expressed by large luteal cells during the late stage of the estrous cycle. In the present study, the amounts of mRNA were determined in cultured cells of the corpus luteum (CL) cells. The localization of 20α-HSD was also determined in ovaries, placenta, and endometrium during early pregnancy. The amount of 20α-HSD mRNA in cultured luteal cells increased with time and by treatment with the luteolysis agent prostaglandin F2α (PGF2α). Immunofluorescence assays detected increased protein in cultured luteal cells. The 20α-HSD mRNA and protein were present in the ovaries, placenta, and endometrium on Days 30, 60, and 90 of pregnancy. In particular, gene expression was much greater in the ovary than in the placenta and endometrium. Immuno-histochemical analysis indicated that bovine 20α-HSD was primarily localized in ovarian large luteal cells, placental cytotrophoblast villus, and glandular epithelial cells of the endometrium during early pregnancy. Furthermore, in situ analyses demonstrated colocalization of 20α-HSD mRNA and protein. Taken together, results of the present study indicate that 20α-HSD mRNA and protein are co-localized in large luteal cells, the placenta, and the endometrium during early pregnancy, suggesting that 20α-HSD regulates mechanisms involved in the maintenance of early pregnancy.

151 PROTEOMICS ANALYSIS OF PREGNANCY-SPECIFIC SERUM PROTEINS IN BOVINE

To identify early pregnancy-specific serum proteins in bovine, we performed proteomics analysis using blood serum samples of pregnant and non-pregnant Holstein dairy cattle Days 21 and 35 after AI. A total of eight pregnant and eight non-pregnant cattle were used for collection of the blood samples. The global proteomics approach was exploited by the use of 2-D gel electrophoresis and mass spectrometry to sort out pregnancy-specific proteins. Serum proteins within isoelectric point ranges of 4.0 to 7.0, 6.0 to 9.0, and 5.5 to 6.7 were analyzed separately by 2-D electrophoresis with three replications of each sample. The stained gels were scanned and calibrated at an optical resolution of 63.5 �m/pixel using a GS-710 imaging densitometer (Bio-Rad Laboratories, Philadelphia, PA, USA). A total of approximately 1200 spots were detected in 2-D gels stained with Coomassie-blue. In the comparison of serum samples from pregnant and non-pregnant cattle, nine pregnancy-specific spots were detected unanimously in Day 21 and Day 35 serum samples. Pregnancy-specific proteins were identified as transferrin, albumin, IgG2a heavy chain constant region, and immunoglobulin gamma heavy chain variable region by means of MALDI-TOF-MS (PerSeptive Biosystems, Framingham, MA, USA). Even though the identified spots were abundant serum proteins, their molecular weights and pI values were different from those of the main serum proteins. Most proteins identified in this analysis appeared to be related with pregnancy-specific subunits or fragments of transferrin, albumin, and IgG. One of the pregnancy-specific proteins, transferrin, is known to be related to iron transport during pregnancy. Western blot analysis using polyclonal anti-transferrin antibody revealed specific transferrin expression in the serum samples from the pregnant cattle but no detectable expression in the serum samples from the non-pregnant cattle. Our results revealed composite profiles of key proteins involved in early pregnancy and suggest the potential use of identified proteins to detect early pregnancy in bovine.

Production of HanWoo (Bos taurus coreanae) fetuses following interbreed somatic cell nuclear transfer

The possibility of producing HanWoo (Bos taurus coreanae) calves from transferable bovine embryos, obtained by interbreed nuclear transfer using Holstein cytoplasts and surrogates, was investigated. As donor nuclei, HanWoo fetal fibroblasts were used. Cells were induced into quiescence by serum deprivation for 4-7 days before nuclear transfer. In vitro matured Holstein oocytes were enucleated, and single donor cell was placed into the perivitelline space of enucleated oocyte. After reconstruction, the embryos were fused. activated and cultured. On day 7, the embryos that developed to the blastocyst stages were transferred into Holstein recipient cows on day 6 to 7 of estrous cycle (estrus=0). The reconstructed embryos were successfully fused (58.8%; 47/80), cleaved (91.5%; 43/47), and developed to blastocysts (29.8%; 14/47). Eleven blastocysts were transferred into 5 Holstein recipient cows. Two recipients were pregnant, confirmed by ultrasonography at day 60 of gestation. But, one of them was opened between on day 80 to 100 of pregnancy, and the other had a stillbirth on day 255. The stillborn calf was physically normal, and we couldn't find any evidence of anomaly. These results show that cells derived from HanWoo somatic cell lines can be reprogrammed by interbreed nuclear transfer and develop subsequently in vivo as well as in vitro.

In vitro development of green fluorescent protein (GFP) transgenic bovine embryos after nuclear transfer using different cell cycles and passages of fetal fibroblasts

Nuclear transfer using transfected donor cells provides an efficient new strategy for the production of transgenic farm animals. The present study assessed in vitro development of nuclear transfer embryos using green fluorescent protein (GFP) gene-transfected bovine fetal fibroblasts. In experiment 1, bovine fetal fibroblasts (BFF) were transfected with linearized pEGFP-N1 by electroporation, and the enucleated oocytes were reconstructed by nuclear transfer of transfected cells (BFF-GFP). The rates of blastocyst formation did not differ significantly between BFF and BFF-GFP (18.2% v. 15.6%). In experiment 2, before nuclear transfer, the donor cell stage was synchronized by serum deprivation or forming a confluent monolayer. The rates of cleavage (67.1% v. 71.8%) and blastocyst formation (15.8% v. 15.5%) did not differ between confluent and serum-starved cells after nuclear transfer. In experiment 3, the effects of different passages of donor fibroblast cells on the development of nuclear transfer embryos were investigated. Donor cells from 'early' (at passage 8-16) showed better blastocyst development (18.9%) than those from 'late' (at passage 17-32; 10.5%). In conclusion, this study suggests that transgenic somatic cell nuclei from early passages can be reprogrammed more effectively than those from late passages. In addition, GFP, a non-invasive selection marker, can be used to select transgenic nuclear transfer embryos.

Effect of dominant follicle removal before superstimulation on follicular growth, ovulation and embryo production in Holstein cows

This study was to investigate whether removing the dominant follicle 48 h before superstimulation influences follicular growth, ovulation and embryo production in Holstein cows. After synchronization, ovaries were scanned to assess the presence of a dominant follicle by ultrasonography with a real-time linear scanning ultrasound system on Days 4, 6 and 8 of the estrus cycle (Day 0 = day of estrus). Twenty-six Holstein cows with a dominant follicle were divided into 2 groups in which the dominant follicle was either removed (DFR group, n=13) by ultrasound-guided follicular aspiration or left intact (control group, n=13) on Day 8 of the estrus cycle. Superovulation treatment was initiated on Day 10. All donors were superovulated with injections of porcine FSH (Folltropin) twice daily with constant doses (total: 400 mg) over 4 d. On the 6th and 7th injections of Folltropin, 30 mg and 15 mg of PGF2alpha (Lutalyse) were given. Donors were inseminated twice at 12 h and 24 h after the onset of estrus. Embryos were recovered on Day 6 or 7 after AI. During superstimulation, the number of follicles 2 to 5 mm (small), 6 to 9 mm (medium) and > or = 10 mm (large) was determined by ultrasonography on a daily basis. At embryo recovery, the number of corpora lutea (CL) was also determined by ultrasonography and blood samples were collected for analysis of progesterone concentration. Follicular growth during superstimulation was earlier in the DFR group than in the control group. The number of medium and large follicles was greater (P < 0.01) in the DFR group than in the control group on Days 1 to 2 and Days 3 to 4 of superstimulation, respectively. The numbers of CL (9.6+/-1.1 vs 6.1+/-0.9) and progesterone concentration (30.9+/-5.4 vs 18.6+/-3.5 ng/mL) were greater (P < 0.05) in the DFR group than in the control group, respectively. The numbers of total ova (7.7+/-1.3 vs 3.9+/-1.0) and transferable embryos (4.6+/-0.9 vs 2.3+/-0.8) were also greater (P < 0.05) in the DFR group than in the control group, respectively. It is concluded that the removal of the dominant follicle 48 h before superstimulation promoted follicular growth, and increased ovulation and embryo production in Holstein cows.

Intracerebral clysis in a rat glioma model

OBJECTIVE

Intracerebral clysis (ICC) is a new term we use to describe convection-enhanced microinfusion into the brain. This study establishes baseline parameters for preclinical, in vivo, drug investigations using ICC in a rat glioma model.

METHODS

Intracranial pressure was measured, with an intraparenchymal fiber-optic catheter, in male Fischer rats 10, 15, 20, and 25 days after implantation of C6 glioma cells in the right frontal lobe (n = 80) and in control rats without tumor (n = 20), before and during ICC. A 25% albumin solution (100 microl) was infused through an intratumoral catheter at 0.5, 1.0, 2.0, 3.0, and 4.0 microl/min. Infusate distribution was assessed by infusion of fluorescein isothiocyanate-dextran (Mr 20,000), using the aforementioned parameters (n = 36). Brains were sectioned and photographed under ultraviolet light, and distribution was calculated by computer analysis (NIH Image for Macintosh). Safe effective drug distribution was demonstrated by measuring tumor sizes and apoptosis in animals treated with N,N'-bis(2-chloroethyl)-N-nitrosourea via ICC, compared with untreated controls. Magnetic resonance imaging noninvasively confirmed tumor growth before treatment.

RESULTS

Intracranial pressure increased with tumor progression, from 5.5 mm Hg at baseline to 12.95 mm Hg on Day 25 after tumor cell implantation. Intracranial pressure during ICC ranged from 5 to 21 mm Hg and was correlated with increasing infusion volumes and increasing rates of infusion. No toxicity was observed, except at the higher ends of the tumor size and volume ranges. Fluorescein isothiocyanate-dextran distribution was greater with larger infusion volumes (30 microl versus 10 microl, n = 8, P < 0.05). No significant differences in distribution were observed when different infusion rates were compared while the volume was kept constant. At tolerated flow rates, the volumes of distribution were sufficient to promote adequate drug delivery to tumors. N,N'-Bis(2-chloroethyl)-N-nitrosourea treatment resulted in significant decreases in tumor size, compared with untreated controls.

CONCLUSION

The C6 glioma model can be easily modified to study aspects of interstitial delivery via ICC and the application of ICC to the screening of potential antitumor agents for safety and efficacy.

Frequent type 2 neurofibromatosis gene transcript mutations in sporadic intramedullary spinal cord ependymomas

OBJECTIVE

To further investigate the role of Type 2 neurofibromatosis (NF2) gene transcript mutations in the sporadically occurring counterparts of NF2-associated tumors.

METHODS

Reverse transcription-polymerase chain reaction followed by agarose gel electrophoresis, single strand conformation polymorphism analysis, and automated deoxyribonucleic acid sequence analysis were used to screen for mutations in the NF2 gene transcript in seven unrelated patients with sporadic intramedullary spinal cord ependymomas.

RESULTS

Five of seven intramedullary spinal cord ependymomas harbored detectable mutations. All of these mutations occurred in the region of the transcript that is homologous to known cytoskeletal proteins and resulted in significant truncation of the predicted protein product.

CONCLUSION

Mutations of the NF2 transcript occur in the majority of sporadic intramedullary spinal cord ependymomas. These mutations are frequent in a region of the transcript that is homologous to a family of cytoskeletal proteins, and they probably render the protein product inactive. These results add to the body of knowledge concerning the role of the NF2 gene transcript in tumorigenesis.