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1

Thermostability of Sperm Nuclei Assessed by Microinjection into Hamster Oocytes.  

National Technical Information Service (NTIS)

Nuclei isolated from spermatozoa of various species (golden hamster, mouse, human, rooster, and the fissh tilapia) were heated at 50 - 125 deg for 20-120 min and then microinjected into hamster oocytes to determine whether they could decondense and develo...

K. Yanagida S. D. Perreault R. G. Kleinfeld R. Yanagimachi

1991-01-01

2

Effects of glutathione (GSH and GSSG) and glutathione reductase (GR) on zona-free hamster oocyte ability to decondense human sperm.  

PubMed

Effects of reduced glutathione (GSH), oxidized glutathione (GSSG), or glutathione reductase (GR) supply were studied on the ability of hamster oocytes to be fertilized by human sperm. Zona-free oocytes were pretreated with these compounds prior to sperm insemination. Oocyte pretreatment with high concentrations of GSH or GSSG (50 or 100 mM, 30 min) significantly increased the penetrated oocyte rate (PR). Polyspermy was not increased except when high concentrations of GSH (100 mM) were used. Incubation of oocytes with GR (1 or 10 IU/ml) prior to sperm insemination induced increasing dose-dependent PR. Polyspermy increased significantly with 10 mM GR in oocyte incubation medium. Oocyte incubation for 30 min with the sulfhydryl blocking agent iodoacetamide (1 mM) led to a drastic decrease in oocyte penetration and in polyspermy. Our results demonstrate an original way to increase the efficacy of human-hamster heterospecific fertilization. Various hypotheses are discussed explaining these observations which open new investigations for heterospecific and homospecific in vitro fertilization. PMID:2591849

Lassalle, B; Testart, J

1989-09-01

3

DNA (Deoxyribonucleic Acid) Synthesis Following Microinjection of Heterologous Sperm and Somatic Cell Nuclei into Hamster Oocytes.  

National Technical Information Service (NTIS)

The authors have investigated the ability of the hamster oocyte to initiate DNA synthesis in nuclei differing in basic protein content. DNA synthesis was studied by autoradiography in oocytes that had been incubated in 3H-thymidine after being parthenogen...

S. J. Naish S. D. Perreault B. R. Zirkin

1987-01-01

4

DNA (deoxyribonucleic acid) synthesis following microinjection of heterologous sperm and somatic cell nuclei into hamster oocytes  

SciTech Connect

The authors investigated the ability of the hamster oocyte to initiate DNA synthesis in nuclei differing in basic protein content. DNA synthesis was studied by autoradiography in oocytes that had been incubated in /sup 3/H-thymidine after being parthenogenetically activated by sham microinjection, or microinjected with hamster, mouse, rabbit, or fish sperm nuclei, or hamster hepatocyte nuclei. Within 6 hr of sham or nucleus microinjection, nuclei of each type underwent transformation into pronuclei and synthesized DNA. These results demonstrated that the hamster egg can access and utilize its own and each type of template provided, whether homologous or heterologous. However, pronuclei derived from hamster sperm nuclei were more likely to be synthesizing DNA at 6 hr than pronuclei derived from sperm nuclei of other species. The authors conclude that the mechanisms employed by the hamster oocyte to transform hamster sperm nuclei into pronuclei and to effect DNA synthesis in these nuclei are not specific for the hamster sperm nucleus. Nevertheless, these mechanisms apparently operate more efficiently when the hamster sperm nucleus, rather than a heterologous sperm nucleus, is present.

Naish, S.J.; Perreault, S.D.; Zirkin, B.R.

1987-01-01

5

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

Microsoft Academic Search

Purpose  To evaluate DNA synthesis and epigenetic modification in mouse oocytes during the first cell cycle following the injection\\u000a of human or hamster sperm.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Mouse oocytes following the injection of human and hamster sperm and cultured in M16 medium.\\u000a \\u000a \\u000a \\u000a Results  Male and female pronucleus formation, DNA synthesis, histone protein modification, and heterochromatin formation were similar\\u000a in mouse oocytes injected with human or

Yong-Nan Xu; Xiang-Shun Cui; Jin-Cheol Tae; Yong-Xun Jin; Nam-Hyung Kim

2011-01-01

6

Colchicine-induced abnormal meiotic chromosomal segregation in primary oocytes of the Chinese hamster  

Microsoft Academic Search

Summary A single dose of 3 ?g\\/g b.w. colchicine was intraperitoneally injected to female Chinese hamsters with a normal estrous cycle at the onset of the formation of the first meiotic spindle. Morphologically abnormal secondary oocytes having one or two extremely large first polar bodies occurred frequently,i.e., 47 (11.3%) out of 416 oocytes. In 30 of them, chromosome analysis was

Kazuya Mikamo; Shigeki Sugawara

1980-01-01

7

Changes in the reciprocal position of the first polar body and oocyte chromosome set in golden hamsters.  

PubMed

The golden hamster is an attractive model organism for studying reproductive physiology, oncology, genetics and virology. In an effort to establish experimental protocols necessary for cloning golden hamsters, we examined changes in the reciprocal position of the FPB (first polar body) and chromosome set of MII (the second meiotic metaphase) oocytes of golden hamsters. Oocytes were collected under three different conditions: (i) oocyte direct recovery from the oviduct of hormonally treated donor; (ii) oocyte recovery from the oviduct of hormonally treated donor followed by 5 h/10 h in vitro culture; and (iii) oocyte recovery from ovaries of hormonally treated donors and in vitro maturation. Then oocyte recovery was performed from the oviduct of hormonally treated donors, followed by 5 h in vitro culture with colchicine and/or CB (cytochalasin B). Denuded oocytes were stained with Hoechst 33342 and propidium iodide and evaluated under a microscope. Our results demonstrate that the change in FPB position in relation to the MII oocyte chromosome set increases with age of in vivo-matured oocytes. Cumulus cells can protect the FPB of in vitro-cultured oocytes from degeneration but do not significantly affect its repositioning, and in vitro-matured oocytes age slower. The colchicine has a stronger effect on cytoplasmic protrusions of golden hamster oocytes when compared with CB. These results define conditions for changes in FPB position relative to the MII oocyte chromosome set. Early ovulated oocytes, in vitro-matured oocytes and oocytes treated with colchicine should improve the effectiveness of the cloning procedure in golden hamsters as an animal model for human diseases. PMID:18980577

Wang, Lingyan; Li, Dexue; Li, Ziyi

2009-06-25

8

Effects of White Blood Cells on the In Vitro Penetration of Zona-free Hamster Eggs by Human Spermatozoa  

Microsoft Academic Search

The presence of white blood cells in semen has been associated with male infertility. Previous studies indi- cate that pyospermia occurs in conjunction with de- creases in sperm motility, number of normal sperm forms, and penetration rates in the zona-free hamster egg sperm penetration assay. We have evaluated the relationship of seminal white blood cells and sperm function, as reflected

DONALD K. MARUYAMA; RALPH W. HALE; B. JANE ROGERS

9

A prospective serial study of the effects of radiotherapy on semen parameters, and hamster egg penetration rates.  

PubMed

Cancer patients were studied before radiotherapy (RT) and at regular intervals after treatment (1, 3, 12, 24, 36, 48 months) to determine the effect of radiotherapy on semen parameters and sperm function as assessed by the hamster egg penetration assay. The cancer patients received testicular radiation doses of 0.4 to 5.0 grays (40 to 500 rads). The pre-radiotherapy semen profile varied considerably but in general the profile was poor: 7/11 men had a sperm concentration less than 20 X 10(6)/ml and a total count of less than 50 X 10(6), while the hamster egg penetration rates were also very low with a mean of 5% (range 0% to 15%). This is the first study demonstrating that sperm function as well as sperm concentration is impaired in cancer patients pre-radiotherapy. At 3 and 12 months post-radiotherapy, 8/11 men were azoospermic. By 24 months 8/11 were producing sperm although only 2 had hamster egg penetration rates greater than 15%. All men studied at 36 months (4) and 48 months (3) post-radiotherapy had recovered spermatogenesis but hamster egg penetration rates were still poor. There was a highly significant inverse correlation between testicular radiation dose and subsequent sperm concentration and hamster egg penetration rates. PMID:4042467

Martin, R H; Rademaker, A; Barnes, M; Arthur, K; Ringrose, T; Douglas, G

1985-01-01

10

Hamsters  

NSDL National Science Digital Library

Scientists believe that most behaviors, from fighting to mating, are controlled by brain chemistry. In this Science Update, you'll hear how researchers are using hamsters to understand the roots of aggression.

Science Update;

2000-03-15

11

Serial study of the effect of radiotherapy on semen parameters, hamster egg penetration rates, and lymphocyte chromosome abnormalities  

SciTech Connect

This study was designed to assess the long-term effects of radiotherapy (RT) on male fertility and the induction of lymphocyte and sperm chromosome abnormalities. This preliminary report provides information on 11 cancer patients (mainly seminomas) treated by RT (testicular dose, 44 to 499 rads). All 11 men were studied pre-RT and at intervals post-RT. The pre-RT semen profile varied considerably, but, in general, the profile was poor with a mean sperm concentration of 19.4 x 10/sup 6/ ml and a mean hamster egg penetration rate of 5%. One month after RT, the sperm concentration decreased and hamster egg penetration was 0% in all men. At 3 and 12 months post-RT, all but two patients were azoospermic. By 24 months post-RT, 9 of 11 patients had regained sperm production and 5 had sperm capable of hamster egg penetration. The three men who have been studied 36 months post-RT had a mean sperm concentration of 45.3 x 10/sup 6/ ml, and all had positive hamster egg penetration tests, although two of the three men had very low penetration rates (2% and 4%). Lymphocyte chromosome analysis demonstrated a striking frequency of chromosome abnormalities post-RT which decreased with time (pre-RT, 0%; 1 month, 42.4%; 3 months, 24.7%; 12 months, 13.8%; 24 months, 11.2%; and 36 months, 10.0%). Thus, it appears that sperm production starts to recover 2 to 3 years after RT when the frequency of lymphocyte chromosome abnormalities has decreased, but the sperm may not be fully functional at this time, as evidenced by poor rates of hamster egg penetration. Future studies of sperm chromosome analysis in these men will determine whether this impairment of the sperm is associated with meiotic chromosome abnormalities.

Martin, R.H.; Barnes, M.; Arthur, K.; Ringrose, T.; Douglas, G.

1984-02-01

12

Biological effects of trilostane in vitro on oocyte maturation and fertilization in the hamster  

Microsoft Academic Search

Summary The effects of the inhibition of steroidogenesis by trilostane on oocyte maturation were examined by studying spontaneous maturation and fertilization in vitro. 10?6 M trilostane had no influence on the meiotic process, whether the oocytes were naked or not. At a concentration of 10?6 M and 10?7 M trilostane, low normal pronuclear formation and high polyspermy were found during

S. Suzuki; Y. Endo; R. Miura; R. Iizuka

1984-01-01

13

Importance of Glutathione in the Acquisition and Maintenance of Sperm Nuclear Decondensing Activity in Maturing Hamster Oocytes.  

National Technical Information Service (NTIS)

Sperm nuclear decondensing activity in mammalian oocytes is dependent upon the maturational state of the oocyte. It is maximal in mature, metaphase II oocytes and minimal or absent in immature germinal vesicle (GV) and fertilized pronuclear oocytes. Previ...

S. D. Perreault R. R. Barbee V. L. Slott

1988-01-01

14

The sperm penetration assay for the assessment of fertilization capacity.  

PubMed

The sperm penetration assay, or zona-free hamster oocyte penetration assay, is utilized to measure the ability of sperm to undergo capacitation, fuse with the egg membrane, and decondense the sperm head within the cytoplasm of the oocyte, resulting in the formation of the male pronucleus. The test is scored by calculation of the percentage of ova that are penetrated (the original assay developed) or the average number of sperm penetrations per ovum (the sperm capacitation index of the optimized assay). The sperm penetration assay identifies those couples that will have a high likelihood of success with in vitro fertilization. PMID:22992907

Hwang, Kathleen; Lamb, Dolores J

2013-01-01

15

IMPORTANCE OF GLUTATHIONE IN THE ACQUISITION AND MAINTENANCE OF SPERM NUCLEAR DECONDENSING ACTIVITY IN MATURING HAMSTER OOCYTES  

EPA Science Inventory

Sperm nuclear decondensing activity in mammalian oocytes is dependent upon the maturational state of the oocyte. It is maximal in mature, metaphase II oocytes and minimal or absent in immature germinal vesicle (GV) and fertilized pronuclear oocytes. Previous studies suggested tha...

16

The Sperm Penetration Assay for the Assessment of Fertilization Capacity  

PubMed Central

Summary The sperm penetration assay, or zona-free hamster oocyte penetration assay is utilized to measure the ability of sperm to undergo capacitation, fuse with the egg membrane and decondense the sperm head within the cytoplasm of the oocyte resulting in the formation of the male pronucleus. The test is scored by calculation the percentage of ova that are penetrated or the average number of sperm penetrations per ovum. It has been used to identify those couples who will have a high likelihood of success with in vitro fertilization.

Hwang, Kathleen; Lamb, Dolores J.

2013-01-01

17

GLUTATHIONE (GSH) CONCENTRATIONS VARY WITH THE CELL CYCLE IN MATURING HAMSTER OOCYTES, ZYGOTES AND PRE-IMPLANTATION STAGE EMBRYOS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Glutathione (GSH) is thought to play critical roles in oocyte function including spindle maintenance and provision of reducing power needed to initiate sperm chromatin decondensation. Previous observations that GSH concentrations are higher in mature than immature oocytes and decline after fertiliz...

18

GLUTATHIONE (GSH) CONCENTRATIONS VARY WITH THE CELL CYCLE IN MATURING HAMSTER OOCYTES, ZYGOTES AND PRE-IMPLANATION EMBRYOS  

EPA Science Inventory

Abstract Glutathione (GSH) is thought to play critical roles in oocyte function including spindle maintenance and provision of reducing power needed to initiate sperm chromatin decondensation. Previous observations that GSH concentrations are higher in mature than immature o...

19

USE OF THE FUNGICIDE CARBENDAZIM AS A MODEL COMPOUND TO DETERMINE THE IMPACT OF ACUTE CHEMICAL EXPOSURE DURING OOCYTE MATURATION AND FERTILIZATION ON PREGNANCY OUTCOME IN THE HAMSTER  

EPA Science Inventory

Here we use a hamster animal model to identify early pregnancy loss due to an acute chemical exposure to the female during the perifertilization interval. The fungicide carbendazim (methyl 1H-benzimidazole-2-carbamate), a microtubule poison with antimitotic activity, was selected...

20

Initial stages in the formation of cytoplasmic lamellae in the hamster oocyte and the identification of associated electron-dense particles  

Microsoft Academic Search

The stage in oocyte development at which cytoplasmic lamellae first appear has been determined and the morphology of the newly formed structures described. An attempt has been made to determine the time of appearance of associated electron-dense particles with respect to the appearance of the lamellae. The electron-dense particles were identified as particulate glycogen by saliva and diastase digestions.

Brenda S. Weakley

1969-01-01

21

Human sperm microinjection into hamster oocytes: a new tool for training and evaluation of the technical proficiency of intracytoplasmic sperm injection  

Microsoft Academic Search

Objective: To design a system for teaching intracytoplasmic sperm injection (ICSI) and to provide a standardized method to assess technical competency.Setting: University andrology laboratory.Design: Prospective study of method for training ICSI and prediction of ICSI outcome.Patient(s): Male infertility candidates for ICSI and fertile donors.Intervention(s): Sperm from 14 fertile donors and 21 oligospermic patients were microinjected into hamster ova. Sperm head

Marina O Gvakharia; Larry I Lipshultz; Dolores J Lamb

2000-01-01

22

Oocyte activation: lessons from human infertility  

Microsoft Academic Search

During fertilization, the spermatozoon penetrates through the cumulus cells and the zona pellucida that surrounds the oocyte, before it binds and fuses with the oocyte plasma membrane to induce activation. In vitro fertilization (IVF) studies performed in non-human mammals have contributed extensive knowledge regarding the mechanisms by which the spermatozoon activates the meiotic-arrested oocyte to resume meiosis, cleave and develop

Dalit Ben-Yosef; Ruth Shalgi

2001-01-01

23

Disposition and metabolic profiling of the penetration enhancer Azone. I. In vitro studies: Urinary profiles of hamster, rat, monkey, and man  

SciTech Connect

Chain-labeled {sup 14}C-Azone was intravenously administered to hamster, monkey, and rat, to compare its metabolic profile with that obtained previously in humans after dermal application. Azone-derived radioactivity was excreted predominantly in the urine for both hamster and monkey, which is similar to the disposition in humans. Metabolic profiling in urine revealed extensive systemic metabolism to occur in all species studied. The main fraction of the metabolites was most polar in man, followed by rat, monkey, and hamster. Traces of the parent compound were detectable only in hamster urine. Although some of the polar major human metabolites were also present in rat urine, the animals were unsuitable for collecting metabolites of Azone observed in humans. In rats, complete cleavage of the dodecyl side chain was ruled out by administering Azone that had been labeled at two distinct positions of the molecule. Additionally, oral administration of Azone to rats resulted in the same metabolic profile as intravenous administration, indicating that gastrointestinal metabolism does not occur or is similar to systemic metabolism.

Wiechers, J.W.; Drenth, B.F.; Adolfsen, F.A.; Prins, L.; de Zeeuw, R.A. (Groningen Centre for Drug Research (Netherlands))

1990-05-01

24

Oocyte donation  

Microsoft Academic Search

Oocyte donation affords women with ovarian failure, advanced reproductive age, heritable conditions or recurrent implantation failure the ability to conceive. Recipients must be medically screened carefully prior to attempting pregnancy. Egg donors should also be healthy and pose no infectious or genetic risk to the recipient or offspring. Donor and recipient menstrual cycles are synchronized so that embryos are transferred

Jeffrey Klein

2002-01-01

25

Timing of Hamster Sperm Nuclear Decondensation and Male Pronucleus Formation Is Related to Sperm Nuclear Disulfide Bond Content.  

National Technical Information Service (NTIS)

The relationship between the timing of both sperm nuclear decondensation and male pronucleus formation in the oocyte and the relative level of disulfide bonds within the sperm nucleus was evaluated. Four types of hamster sperm nuclei, in which the extent ...

S. D. Perreault S. J. Naish B. R. Zirkin

1987-01-01

26

The inhibition of the human sperm phosphatidylinosytol 3-kinase by LY294002 does not interfere with sperm/oocyte interaction.  

PubMed

It has recently been reported that the selective inhibition of phosphatidylinosytol 3-kinase (PI3K) enhances human sperm motility. However, little information exists on a possible role of PI3K in other sperm functions involved in the fertilization process. In this study, we investigated whether LY294002 could affect human sperm ability to fuse with oocytes, by means of the hamster egg penetration test (HEPT). The effect on acrosome reactions (AR) and on sperm/zona pellucida (ZP) binding was also evaluated. The pre-incubation with scalar doses of LY294002 (0.1, 1 and 10 microm) did not interfere with sperm ability to fuse with oocytes either in the conventional version of the HEPT or in the version enhanced with progesterone (P). No interference with the stimulatory effect on AR exerted by P or mannose-bovine serum albumin (mannose-BSA) was revealed. Finally, LY294002 had no effect on sperm/ZP binding. These results indicate that the inhibition of PI3K by LY294002 does not interfere with sperm interaction with oocytes. This is noteworthy in the view of a possible clinical use of LY294002 as an in vitro stimulator of the sperm motility of asthenozoospermic patients for assisted reproduction techniques. PMID:16480410

Barbonetti, A; Zugaro, A; Sciarretta, F; Santucci, R; Necozione, S; Ruvolo, G; Francavilla, S; Francavilla, F

2006-02-15

27

Dose-dependent relationship between oocyte cytoplasmic volume and transformation of sperm nuclei to metaphase chromosomes  

Microsoft Academic Search

We have studied the chromosome condensa- tion activity of mouse oocytes that have been insemi- nated during meiotic maturation. These oocytes remain unactivated, and in those penetrated by up to three or four sperm, each sperm nucleus is transformed, with- out prior development of a pronucleus, into metaphase chromosomes. However, those penetrated by more than four sperm never transform any

Hugh J. Clarke; Yoshio Masui

1987-01-01

28

Fertilization current in the human oocyte.  

PubMed

In this report we show that the first event of activation in the human oocyte, the Fertilization current (FC), is a slow transient outward current of 300 pA, which induces a gradual hyperpolarization of the plasma membrane from -20mV to -60mV, 60-120 min after insemination, followed by a repolarization to -20mV. Activation currents (AC) of 600-2,500 pA, induced by exposure to the calcium ionophore A23187 or by microinjection of InsP3 into the cytosol, are also outward. The AC are inhibited by preloading oocytes with EGTA suggesting they are calcium dependent. Since AC are 2-10-fold the amplitude of the FC the fertilizing spermatozoon in the human only activates a portion of the primary elements stored in the oocyte for triggering metabolic depression. Oocyte activation in the human resembles that in the hamster rather than other mammals or invertebrates studied to date. PMID:8080650

Gianaroli, L; Tosti, E; Magli, C; Iaccarino, M; Ferraretti, A P; Dale, B

1994-06-01

29

A new model for asymmetric spindle positioning in mouse oocytes.  

PubMed

An oocyte matures into an egg by extruding half of the chromosomes in a small polar body. This extremely asymmetric division enables the oocyte to retain sufficient storage material for the development of the embryo after fertilization. To divide asymmetrically, mammalian oocytes relocate the spindle from their center to the cortex. In all mammalian species analyzed so far, including human, mouse, cow, pig, and hamster, spindle relocation depends on filamentous actin (F-actin). However, even though spindle relocation is essential for fertility, the involved F-actin structures and the mechanism by which they relocate the spindle are unknown. Here we show in live mouse oocytes that spindle relocation requires a continuously reorganizing cytoplasmic actin network nucleated by Formin-2 (Fmn2). We found that the spindle poles were enriched in activated myosin and pulled on this network. Inhibition of myosin activation by myosin light chain kinase (MLCK) stopped pulling and spindle relocation, indicating that myosin pulling creates the force that drives spindle movement. Based on these results, we propose the first mechanistic model for asymmetric spindle positioning in mammalian oocytes and validate five of its key predictions experimentally. PMID:19062278

Schuh, Melina; Ellenberg, Jan

2008-12-08

30

Penetration enhancers  

Microsoft Academic Search

One long-standing approach for improving transdermal drug delivery uses penetration enhancers (also called sorption promoters or accelerants) which penetrate into skin to reversibly decrease the barrier resistance. Numerous compounds have been evaluated for penetration enhancing activity, including sulphoxides (such as dimethylsulphoxide, DMSO), Azones (e.g. laurocapram), pyrrolidones (for example 2-pyrrolidone, 2P), alcohols and alkanols (ethanol, or decanol), glycols (for example propylene

Adrian C Williams; Brian W Barry

2004-01-01

31

An experimental approach to the analysis of mechanisms of meiotic nondisjunction and anaphase lagging in primary oocytes  

Microsoft Academic Search

The in vivo genomic mutagenicity of colchicine in Chinese hamster primary oocytes was analyzed at a carefully chosen dose that did not completely arrest the formation of the first meiotic spindle but exhibited a remarkable ability to induce nondisjunction, very possibly as a result of inhibition of tubulin polymerization. A single dose of 3 ?g of colchicine per gram body

S. Sugawara; K. Mikamo

1980-01-01

32

Assessment of the genotoxicity of three cryoprotectants used for human oocyte vitrification: Dimethyl sulfoxide, ethylene glycol and propylene glycol  

Microsoft Academic Search

Vitrification requires high concentrations of cryoprotectants that may induce long-term toxic effects on cells. The aim of this study was to evaluate the possible genotoxicity of three cryoprotectants extensively used for oocyte vitrification: dimethyl sulfoxide (DMSO), ethylene glycol (EG) and propylene glycol (PROH). For this purpose, a Chinese Hamster Ovary cell line (CHO), commonly used in genetic toxicology, was selected

M. Aye; C. Di Giorgio; M. De Mo; A. Botta; J. Perrin; B. Courbiere

2010-01-01

33

Curiosity in the hamster  

Microsoft Academic Search

Running time for repeated alley runs by hamsters to end boxes containing (a) nothing, (b) a constant set of objects, or (c) a changing set of objects was in the order a > b > c: thus, novelty appeared reinforcing. Length of intersession interval (2, 24, 48 hr.) affected only Condition b: thus, \\

Gerald E. Schneider; Charles G. Gross

1965-01-01

34

Penetration equations  

SciTech Connect

In 1967, Sandia National Laboratories published empirical equations to predict penetration into natural earth materials and concrete. Since that time there have been several small changes to the basic equations, and several more additions to the overall technique for predicting penetration into soil, rock, concrete, ice, and frozen soil. The most recent update to the equations was published in 1988, and since that time there have been changes in the equations to better match the expanding data base, especially in concrete penetration. This is a standalone report documenting the latest version of the Young/Sandia penetration equations and related analytical techniques to predict penetration into natural earth materials and concrete. 11 refs., 6 tabs.

Young, C.W. [Applied Research Associates, Inc., Albuquerque, NM (United States)

1997-10-01

35

Meiotic progression, mitochondrial features and fertilisation characteristics of porcine oocytes with different G6PDH activities.  

PubMed

The aim of the present study was to investigate the developmental competence, mitochondrial characteristics and chromatin status of immature follicular porcine oocytes selected for their glucose-6-phosphate dehydrogenase (G6PDH) activity by brilliant cresyl blue (BCB) staining. In Experiment 1, the oocyte parameters were determined in parallel right after BCB staining (T(0)), after 22 h of in vitro maturation (IVM) (T(22)) and after 44 h of IVM (T(44)) (n = 496). BCB-stained oocytes (BCB+) at T(0) were characterised by fibrillated chromatin filaments in their germinal vesicles (GV) and diakinesis stages whereas unstained (BCB-) oocytes at T(0) contained in their GV mainly condensed stages of chromatin (P < 0.05). After 22 h of IVM BCB+ oocytes showed a prominent chromatin configuration of metaphase I and after 44 h the majority developed a M II nuclear configuration in contrast to the BCB- group (P < 0.0001). Differences were also observed between the two oocyte populations in their mitochondrial activity (P < 0.05). At the beginning of IVM BCB+ oocytes were characterised by high mitochondrial activity in their cytoplasm. The BCB+ oocytes showed clear visible homogenous distributions of mitochondria (P < 0.005) and contained more aggregated clusters of mitochondria in contrast to BCB- oocytes (P < 0.005). In Experiment 2, 318 oocytes were tested for their G6PDH activity and introduced to IVM and IVF. Only oocytes from the BCB+ group, which were matured after 44 h up to the stage of M II (81.6%) were fertilised (17.4%), penetrated (46%) or activated (15.6%) after IVF. These results indicate a relationship between the G6PDH activity of porcine oocytes before IVM and their subsequent nuclear development, mitochondrial activity and aggregation. PMID:20450835

Egerszegi, István; Alm, Hannelore; Rátky, József; Heleil, Bassiouni; Brüssow, Klaus-Peter; Torner, Helmut

2010-01-01

36

Criteria to assess human oocyte quality after cryopreservation.  

PubMed

Oocyte cryopreservation certainly represents one of the most attractive developments in the field of assisted reproduction, with the aim of preserving female fertility and circumventing the ethical and legal drawbacks associated with embryo freezing. Despite the achievement of the first pregnancy from frozen oocytes dating back as early as 1987, since then fewer than 150 pregnancies have been reported. Over a long period of time, application of oocyte storage on a large scale has been prevented by various factors, namely poor post-thaw survival. Fertilization rates remained low even after the introduction of intracytoplasmic sperm injection. Modifications of slow-freezing protocols, mainly based on the increase of the concentration of sucrose used as non-penetrating cryoprotectant (CPA) and the replacement of sodium with choline, appear to have decisively improved survival rates to over 80%. Investigations at the cellular level on thawed oocytes are largely lacking. Fertilization rates have also benefited from protocol modifications, reaching values indistinguishable from those normally obtained with fresh material. Vitrification protocols have also been tested, giving rise to improvements whose reproducibility is still uncertain. Data on the dynamics of fertilization and preimplantation development of embryos derived from frozen oocytes are extremely scarce. At the moment, clinical efficiency of oocyte cryopreservation cannot be precisely assessed because of the lack of controlled studies, although it appears to be considerably lower than that achieved with embryo freezing. In summary, encouraging advances have been made in the field of oocyte cryopreservation, but presently no protocol can ensure standards of success and safety comparable to those guaranteed by embryo storage. PMID:16274599

Coticchio, G; Bonu, M A; Bianchi, V; Flamigni, C; Borini, A

2005-10-01

37

Scanning electron microscopy of the zona pellucida of human oocytes during intracytoplasmic sperm injection (ICSI).  

PubMed

During intracytoplasmic sperm injection (ICSI) approximately 10% of all injected oocytes degenerate. The reason for this process is unknown. It has been speculated that the mechanical procedure of the insertion of the ICSI needle induces injuries to the zona pellucida which lead to the death of the cell. By scanning electron microscope (SEM), it could be shown that the surface structure of mature oocytes is extremely elastic so that the injection needle penetrates the zona pellucida without destroying the mesh-like or more compact surface. No tissue pieces or zona fragments were detectable. After a culture time of 15 min the penetration site on the zona was no longer easily visible. We believe that oocyte degeneration is not caused by the penetration of a glass needle into the ooplasm but by an injury to the meiotic spindle or by an excessive dose of fluid [polyvinylpyrrolidone (PVP) or medium] during sperm injection. PMID:9021374

Schwartz, P; Magerkurth, C; Michelmann, H W

1996-12-01

38

Photoperiodic Control of Hamster Testis  

Microsoft Academic Search

The response of the testes of juvenile and adult hamsters to various photoperiods was examined. The testes of juvenile animals reached maturity regardless of the light cycle on which the animals were raised. However, the testes of adult hamsters required at least 12.5 hours of light per day to maintain spermatogenesis and prevent degeneration. This is one of the few

Suzanne Gaston; Michael Menaker

1967-01-01

39

Incorporation of the acrosome into the oocyte during intracytoplasmic sperm injection could be potentially hazardous to embryo development  

PubMed Central

In mice and humans, a normal offspring can be obtained by injecting a single spermatozoon into an oocyte, the process called intracytoplasmic sperm injection (ICSI). When three or more mouse spermatozoa with intact acrosomes were injected into individual mouse oocytes, an increasing proportion of oocytes became deformed and lysed. Oocytes did not deform and lyse when acrosome-less spermatozoa were injected, regardless of the number of spermatozoa injected. Injection of more than four human spermatozoa into a mouse oocyte produced vacuole-like structures in each oocyte. This vacuolation did not happen when spermatozoa were freed from acrosomes before injection. Hamsters, cattle, and pigs have much larger acrosomes than the mouse or human. Injection of a single acrosome-intact hamster, bovine, and porcine spermatozoon deformed and lysed many or all mouse oocytes. This deformation did not happen when these spermatozoa were freed from acrosomes before ICSI, regardless of the number of spermatozoa injected. Because trypsin and hyaluronidase mimicked the action of acrosome-intact spermatozoa, it is likely that the acrosomal enzymes deform and lyse the oocytes. Injection of small amounts of trypsin and hyaluronidase into normally fertilized mouse eggs disturbed their pre- and postimplantation development. In view of potentially harmful effects of acrosomal enzymes on embryo development, the removal of acrosomes before ICSI is recommended for animals with large sperm acrosomes. The removal of acrosomes may increase the efficiency of ICSI in these animals. Although human and mouse spermatozoa do not need to be freed from acrosomes, the removal of acrosomes before ICSI is theoretically preferable.

Morozumi, Kazuto; Yanagimachi, Ryuzo

2005-01-01

40

Skin Penetration  

Microsoft Academic Search

\\u000a Penetration of the skin is a key element in cutaneous reactions to xenobiotics, drugs, or other compounds. The structure of\\u000a the skin is described in the present chapter. Based on this structure analysis, theoretical diffusion models are presented.\\u000a The inter- and intraindividual variation in the skin-barrier function is discussed and the complex influence of a carrier\\u000a medium on percutaneous absorption

Hans Schaefer; Thomas E. Redelmeier; Jürgen Lademann

41

Dynamics of zonula occludens-2 expression during preimplantation embryonic development in the hamster  

PubMed Central

The objective was to study the expression of zonula occludens-2, a tight junction protein, during preimplantation hamster embryonic development, to predict its possible localization, source, and roles in trophectoderm differentiation and blastocyst formation in this species. Comparison of zonula occludens-2 expression pattern between the hamster and mouse preimplantation embryos from the zygote up to the blastocyst stage was also an objective of this study. Zonula occludens-2 localization was noted in nuclei of blastomeres in all stages of hamster and mouse embryonic development. Compared to mice, where zonula occludens-2 was first localized in the interblastomere membrane at the morula stage, hamster embryos had membranous zonula occludens-2 localization from the 2-cell stage onwards. Based on combined results of immunolocalization study in parthenogenic embryos and ovarian and epididymal sections, and quantitative PCR done in oocytes and all developmental stages of preimplantation embryos, perhaps there was a carry-over of zonula occludens-2 proteins or mRNA from the dam to the embryo. Based on these findings, we inferred that maternally derived zonula occludens-2 was involved in nuclear functions, as well as differentiation of blastomeres and blastocoel formation during preimplantation embryonic development in the hamster.

Wang, Hehai; Luan, Liming; Ding, Tianbing; Brown, Naoko; Reese, Jeff; Paria, B.C.

2011-01-01

42

The effects of taurine and hypotaurine on in vitro fertilization in the golden hamster  

Microsoft Academic Search

Summary. Using an experimental design in which the addition of hypotaurine or epinephrine was staggered through time, evidence was found that suggests these two compounds are working independently and sequentially to stimulate the fertilizing capacity of hamster spermatozoa in vitro. Prior exposure of spermatozoa to hypotaurine is a prerequisite for the action of epinephrine in causing activation and penetration of

M. Lorraine Leibfried; Barry D. Bavister

1981-01-01

43

Preovulatory follicular fluid during in vitro maturation decreases polyspermic fertilization of cumulus-intact porcine oocytes in vitro maturation of porcine oocytes.  

PubMed

Porcine follicular fluid (pFF), as a supplement of maturation media, has been shown several times to improve the in vitro production (IVP) of porcine embryos. As a transudate of serum, pFF contains locally produced factors in addition to the ones derived from serum. The objective of this study was to determine the additional positive effects of these pFF specific factors on the nuclear and cytoplasmic maturation of porcine oocytes. Follicular fluid and autologous serum were collected from sows in the preovulatory phase of the estrous cycle. Subsequently, oocytes from prepubertal gilts were matured in NCSU23 supplemented with either 10% pFF or 10% autologous serum derived from the same sow. Oocytes were then fertilized and the putative zygotes were cultured for 7 days. Nuclear maturation and cumulus expansion were assessed after the maturation culture. For evaluation of cytoplasmic maturation, oocyte glutathione (GSH) content, fertilization parameters and embryonic development were evaluated. After in vitro maturation (IVM) of the oocytes, both cumulus expansion rate and oocyte GSH content were increased for oocytes matured in pFF (P<0.05). More monospermic penetration was found when cumulus-intact oocytes had been matured in 10% pFF but this effect was lost after fertilization of cumulus denuded oocytes indicating that the pFF was acting through the cumulus. We speculate that the increased cumulus expansion and increased glutathione content, which were prevalent after IVM in pFF, are responsible for the positive effects on fertilization and the pre-implantation development of the embryos. PMID:18572236

Bijttebier, J; Van Soom, A; Meyer, E; Mateusen, B; Maes, D

2008-06-24

44

Cryopreservation of unfertilized human oocytes.  

PubMed

Previous investigations revealed that choline-based freezing media developed in our laboratory were superior to conventional sodium-based media for storing mouse oocytes. This paper examines the ability of the choline-based medium CJ2 and a modified form of this medium, CJ3, to cryopreserve unfertilized human oocytes. Oocytes that were consented for research and matured overnight, as well as freshly collected, donor, mature metaphase II (MII) oocytes, were cryopreserved using choline-based media and an optimized slow-cooling protocol. The results showed higher survival and fertilization rates when CJ3 supplemented with 0.2 mmol/l sucrose was used as compared with CJ2 supplemented with either 0.1 mmol/l or 0.2 mmol/l sucrose. Freshly collected oocytes were more difficult to cryopreserve than those matured in vitro. Modification of the base medium proved to be one of the key factors in obtaining survival rates over 90%. Fertilization rates, embryo development, and genetic analysis of embryos resulting from control and frozen-thawed oocytes are provided. There appears to be a high correlation between chromosomal anomalies and abnormal morphology in embryos from thawed oocytes. PMID:16895636

Stachecki, James J; Cohen, Jacques; Garrisi, John; Munné, Santiago; Burgess, Colleen; Willadsen, Steen M

2006-08-01

45

Chromosome transfer in mature oocytes  

PubMed Central

In this article, we describe detailed protocols for the isolation and transfer of spindle–chromosomal complexes between mature, metaphase II-arrested oocytes. In brief, the spindle–chromosomal complex is visualized using a polarized microscope and extracted into a membrane-enclosed karyoplast. Chromosomes are then reintroduced into an enucleated recipient egg (cytoplast), derived from another female, by karyoplast–cytoplast membrane fusion. Newly reconstructed oocytes consist of nuclear genetic material from one female and cytoplasmic components, including mitochondria and mitochondrial DNA (mtDNA), from another female. This approach yields developmentally competent oocytes suitable for fertilization and producing embryonic stem cells or healthy offspring. The protocol was initially developed for monkey oocytes but can also be used in other species, including mouse and human oocytes. Potential clinical applications include mitochondrial gene replacement therapy to prevent transmission of mtDNA mutations and treatment of infertility caused by cytoplasmic defects in oocytes. Chromosome transfer between the cohorts of oocytes isolated from two females can be completed within 2 h.

Tachibana, Masahito; Sparman, Michelle; Mitalipov, Shoukhrat

2011-01-01

46

Microinjection of follicle-enclosed mouse oocytes  

PubMed Central

Summary The mammalian oocyte develops within a complex of somatic cells known as a follicle, within which signals from the somatic cells regulate the oocyte, and signals from the oocyte regulate the somatic cells. Because isolation of the oocyte from the follicle disrupts these communication pathways, oocyte physiology is best studied within an intact follicle. Here we describe methods for quantitative microinjection of follicle-enclosed mouse oocytes, thus allowing the introduction of signaling molecules as well as optical probes into the oocyte within its physiological environment.

Jaffe, Laurinda A.; Norris, Rachael P.; Freudzon, Marina; Ratzan, William J.; Mehlmann, Lisa M.

2011-01-01

47

Immunity to Toxoplasmosis in Hamsters.  

National Technical Information Service (NTIS)

Protective immunity to Toxoplasma was studied in hamsters. Immunity developed in 2 to 3 weeks after vaccinations were performed. Vaccination with live RH, T-45, and ts-4 strains afforded the best protection against challenge exposure with the most pathoge...

M. R. Elwell J. K. Frenkel

1984-01-01

48

Genetic screening of prospective oocyte donors  

Microsoft Academic Search

Objective: To report our experience with genetic screening of oocyte donor candidates and to determine the frequency with which significant genetic issues are identified.Design: Prospective genetic screening of oocyte donor candidates.Setting: University hospital oocyte donation program.Patient(s): Women presenting consecutively as volunteer oocyte donors.Intervention(s): Genetic screening was performed by pedigree analysis and laboratory studies.Main Outcome Measure(s): Inclusion in the oocyte donor

Robert Wallerstein; Valerie Jansen; Jamie A. Grifo; Alan S. Berkeley; Nicole Noyes; Jennifer Licker; Frederick Licciardi

1998-01-01

49

Dephosphorylation of sperm midpiece antigens initiates aster formation in rabbit oocytes.  

PubMed Central

During fertilization in most mammals, the penetrating sperm organizes an aster of microtubules. We have investigated the mechanisms underlying this function of the sperm by a series of experiments based on microinjection of isolated sperm midpieces into unfertilized oocytes. These midpieces contain antigens recognized by the MPM-2 antibody. These antigens, which are absent from the rest of the tail fraction, correspond to three phosphorylated polypeptides of 77, 81, and 85 kDa. Dephosphorylation with alkaline phosphatase abolishes antigenicity on blots and in whole sperm. Reactivity to the antibody disappears between 1 and 3 hr after calcium stimulation of oocytes, following the decline in H1 kinase activity and coincident with aster formation. In unactivated oocytes, no aster forms and the antigen remains unchanged. MPM-2 treatment of midpieces prior to injection blocks their ability to form asters in oocytes activated by calcium stimulation. The epitope also disappears in 6-methyl-aminopurine-treated oocytes, implying that maintenance of the phosphorylated state requires kinase activity. A result that confirms this view is that sperm midpieces dephosphorylated by alkaline phosphatase can be rephosphorylated after injection into oocytes or by exposure in vitro to a Xenopus oocyte cytoplasmic fraction high in H1 kinase activity. We suggest that the microtubule nucleation activity of sperm midpieces after fertilization is triggered by the calcium-induced decrease in maturation promoting factor, which results in dephosphorylation of specific sperm centrosomal proteins. Images

Pinto-Correia, C; Poccia, D L; Chang, T; Robl, J M

1994-01-01

50

How do spermatozoa activate oocytes?  

PubMed

Although the spermatozoon is 500,000 times smaller in volume than the oocyte, it induces rapid and dramatic changes in oocyte physiology that lead to meiosis re-initiation. These oocyte activation events are described here, as is the evidence for a soluble activating factor in the spermatozoon. Since changes in plasma membrane conductance, calcium ion release and maturation-promoting factor inactivation are common to all animal oocytes at activation, it is expected that the sperm-borne trigger is also ubiquitous. One likely candidate, phospholipase C (PLC) zeta 1, induces calcium release in mammalian oocytes; however, work on other deuterostomes suggests that the sperm factor is non-specific and multifactorial, regulating several activation events. Human, sea urchin and ascidian gametes are remarkably similar and comparative studies across the deuterostomes may help in elucidating basic principles in fertilization. Questions to be answered include the identification of PLC zeta 1 in invertebrate spermatozoa and the characterization of other targets in mammalian oocytes, such as the adenosine diphosphate ribose/nitric oxide pathway. PMID:20378416

Dale, Brian; Wilding, Martin; Coppola, Gianfranco; Tosti, Elizabetta

2010-02-14

51

Nanoliter droplet vitrification for oocyte cryopreservation  

PubMed Central

Aim Oocyte cryopreservation remains largely experimental, with live birth rates of only 2–4% per thawed oocyte. In this study, we present a nanoliter droplet technology for oocyte vitrification. Materials & methods An ejector-based droplet vitrification system was designed to continuously cryopreserve oocytes in nanoliter droplets. Oocyte survival rates, morphologies and parthenogenetic development after each vitrification step were assessed in comparison with fresh oocytes. Results Oocytes were retrieved after cryoprotectant agent loading/unloading, and nanoliter droplet encapsulation showed comparable survival rates to fresh oocytes after 24 h in culture. Also, oocytes recovered after vitrification/thawing showed similar morphologies to those of fresh oocytes. Additionally, the rate of oocyte parthenogenetic activation after nanoliter droplet encapsulation was comparable with that observed for fresh oocytes. This nanoliter droplet technology enables the vitrification of oocytes at higher cooling and warming rates using lower cryoprotectant agent levels (i.e., 1.4 M ethylene glycol, 1.1 M dimethyl sulfoxide and 1 M sucrose), thus making it a potential technology to improve oocyte cryopreservation outcomes.

Zhang, Xiaohui; Khimji, Imran; Shao, Lei; Safaee, Hooman; Desai, Khanjan; Keles, Hasan Onur; Gurkan, Umut Atakan; Kayaalp, Emre; Nureddin, Aida; Anchan, Raymond M; Maas, Richard L; Demirci, Utkan

2011-01-01

52

Recent progress in reproduction of whale oocytes.  

PubMed

Whale oocytes recovered from follicles can be matured in vitro. Whale sperm and mature oocytes can be used for in vitro fertilization (IVF), and IVF embryos have the ability to develop to morula stage. Whale sperm injected into bovine or mouse oocytes can activate the oocytes and form pronucleus. Interspecies somatic cell nuclear transfer embryos have been reconstructed with whale somatic cell nucleus and enucleated bovine or porcine oocytes, and interspecies cloned embryos can develop in vitro. This paper reviews recent progress in maturation, fertilization and development of whale oocytes. PMID:21838965

Zheng, Yue-Liang

2011-08-15

53

Morphological features of lipid droplet transition during porcine oocyte fertilisation and early embryonic development to blastocyst in vivo and in vitro.  

PubMed

Lipid content in mammalian oocytes or embryos differs among species, with bovine and porcine oocytes and embryos showing large cytoplasmic droplets. These droplets are considered to play important roles in energy metabolism during oocyte maturation, fertilisation and early embryonic development, and also in the freezing ability of oocytes or embryos; however, their detailed distribution or function is not well understood. In the present study, changes in the distribution and morphology of porcine lipid droplets during in vivo and in vitro fertilisation, in contrast to parthenogenetic oocyte activation, as well as during their development to blastocyst stage, were evaluated by transmission electron microscopy (TEM). The analysis of semi-thin and ultra-thin sections by TEM showed conspicuous, large, electron-dense lipid droplets, sometimes associated with mitochondrial aggregates in the oocytes, irrespective of whether the oocytes had been matured in vivo or in vitro. Immediately after sperm penetration, the electron density of the lipid droplets was lost in both the in vivo and in vitro oocytes, the reduction being most evident in the oocytes developed in vitro. Density was restored in the pronculear oocytes, fully in the in vivo specimens but only partially in the in vitro ones. The number and size of the droplets seemed, however, to have decreased. At 2- to 4-cell and blastocyst stages, the features of the lipid droplets were almost the same as those of pronuclear oocytes, showing a homogeneous or saturated density in the in vivo embryos but a marbled or partially saturated appearance in the in vitro embryos. In vitro matured oocytes undergoing parthenogenesis had lipid droplets that resembled those of fertilised oocytes until the pronuclear stage. Overall, results indicate variations in both the morphology and amount of cytoplasmic lipid droplets during porcine oocyte maturation, fertilisation and early embryo development as well as differences between in vivo and in vitro development, suggesting both different energy status during preimplantation development in pigs and substantial differences between in vitro and in vivo development. PMID:12463532

Kikuchi, Kazuhiro; Ekwall, Hans; Tienthai, Paisan; Kawai, Yasuhiro; Noguchi, Junko; Kaneko, Hiroyuki; Rodriguez-Martinez, Heriberto

2002-11-01

54

An overview of oocyte cryopreservation.  

PubMed

The ability to cryopreserve human oocytes and store them indefinitely would be beneficial for cancer patients at risk of becoming sterile after therapy, allow women to delay reproduction, and alleviate religious concerns associated with embryo storage. In 1986, Chen was the first to report a pregnancy originating from a frozen-thawed human oocyte. Although over 100 babies have been born from oocyte storage since then, pregnancy rates remain unacceptably low. Adapting embryo cryopreservation techniques to oocyte storage has had limited success and new reproducible methods are needed. Problem areas other than intracellular ice formation and osmotic effects need to be identified. A broad approach of critical analysis should be conducted regarding the entire cryopreservation process from pre-equilibration and cooling, to thawing and stepout. All established facets deserve reanalysis in order to assess which aspects can be optimized or changed so that cellular demise can be avoided and cellular viability enhanced. New methods, including the use of choline-based media and vitrification have proven useful in increasing survival and pregnancy rates in some clinics. Other methods yet untested, such as injection of complex carbohydrates into the oocyte, deserve further studies. Vitrification research has led to the formulation of new ideas and has demonstrated the flexibility of cells to survive cryopreservation. Although successful, vitrification protocols are potentially harmful and technically challenging, due to elevated cryoprotectant concentrations and rapid cooling rates. Bovine embryo vitrification methods have been used to store human oocytes and embryos, particularly blastocysts with some success. Vitrification solutions containing high molecular weight polymers have also proved beneficial by reducing solution toxicity. In general, further advances are needed to improve human oocyte storage before widespread routine clinical use. PMID:15333244

Stachecki, James J; Cohen, Jacques

2004-08-01

55

Comparison and Avoidance of Toxicity of Penetrating Cryoprotectants  

PubMed Central

The objective of this study was to elucidate the toxicity of widely used penetrating cryoprotective agents (CPAs) to mammalian oocytes. To this end, mouse metaphase II (M II) oocytes were exposed to 1.5 M solutions of dimethylsulfoxide (DMSO), ethylene glycol (EG), or propanediol (PROH) prepared in phosphate buffered saline (PBS) containing 10% fetal bovine serum. To address the time- and temperature-dependence of the CPA toxicity, M II oocytes were exposed to the aforementioned CPAs at room temperature (RT, ?23°C) and 37°C for 15 or 30 minutes. Subsequently, the toxicity of each CPA was evaluated by examining post-exposure survival, fertilization, embryonic development, chromosomal abnormalities, and parthenogenetic activation of treated oocytes. Untreated oocytes served as controls. Exposure of MII oocytes to 1.5 M DMSO or 1.5 M EG at RT for 15 min did not adversely affect any of the evaluated criteria. In contrast, 1.5 M PROH induced a significant increase in oocyte degeneration (54.2%) and parthenogenetic activation (16%) under same conditions. When the CPA exposure was performed at 37°C, the toxic effect of PROH further increased, resulting in lower survival (15%) and no fertilization while the toxicity of DMSO and EG was still insignificant. Nevertheless, it was possible to completely avoid the toxicity of PROH by decreasing its concentration to 0.75 M and combining it with 0.75 M DMSO to bring the total CPA concentration to a cryoprotective level. Moreover, combining lower concentrations (i.e., 0.75 M) of PROH and DMSO significantly improved the cryosurvival of MII oocytes compared to the equivalent concentration of DMSO alone. Taken together, our results suggest that from the perspective of CPA toxicity, DMSO and EG are safer to use in slow cooling protocols while a lower concentration of PROH can be combined with another CPA to avoid its toxicity and to improve the cryosurvival as well.

Szurek, Edyta A.; Eroglu, Ali

2011-01-01

56

Hyperadrenocorticism in Three Teddy Bear Hamsters  

PubMed Central

Hyperadrenocorticism was diagnosed in three related teddy bear hamsters with presenting complaints of alopecia and hyperpigmentation of the skin. Treatment was attempted in two of the hamsters and was successful in one case. Metyrapone and o,p?-DDD (1,1-dichloro-2-2bis (p-chlorophenyl) ethane) were the drugs used. Necropsy and histopathological examinations revealed a pituitary chromophobe adenoma in one hamster and an adrenocortical adenocarcinoma in a second hamster. The third related hamster was clinically diagnosed as having hyperadrenocorticism but the origin of the disease has not yet been determined. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.

Bauck, L. (Brouwer); Orr, J. P.; Lawrence, K. H.

1984-01-01

57

Nuclear and Spindle Positioning during Oocyte Meiosis  

PubMed Central

Female meiosis is unique in that an asymmetrically positioned meiotic spindle expels chromosomes into tiny, non-developing polar bodies. The extrusion of chromosomes into polar bodies is always mediated by meiotic spindles that are attached to the oocyte cortex by one pole. The asymmetric, cortical positioning of the oocyte meiotic spindle preserves the volume and contents of the oocyte. Recent work in C. elegans and mouse has provided mechanistic details of spindle positioning in oocytes.

Fabritius, Amy S.; Ellefson, Marina L.; McNally, Francis J.

2010-01-01

58

Use of sugars in cryopreserving human oocytes  

Microsoft Academic Search

In the last 20 years, a worldwide effort to cryopreserve oocytes has resulted in 40 infants and approximately 50 ongoing pregnancies being reported. While the ability to freeze human embryos has become a standard of practice in assisted reproductive technologies, obtaining reliable techniques for oocyte cryopreservation has been more difficult. The unique properties of the mature oocyte, such as the

Diane L Wright; Ali Eroglu; Mehmet Toner; Thomas L Toth

2004-01-01

59

Temperature Preference in Golden Hamsters.  

National Technical Information Service (NTIS)

The preferences of pre-and-post-hibernative hamsters for relatively cool (8C) or relatively warm (19C or 24C) environmental temperatures was tested in a T-maze using the method of forced choice to equate number of visits to, and total time spent in each e...

M. R. Gumma F. E. South H. N. Allen

1967-01-01

60

Mouse oocytes fertilised by ICSI during in vitro maturation retain the ability to be activated after refertilisation in metaphase II and can generate Ca2+ oscillations  

PubMed Central

Background At fertilisation, mammalian oocytes are activated by oscillations of intracellular Ca2+ ([Ca2+]i). Phospholipase C?, which is introduced by fertilising spermatozoon, triggers [Ca2+]i oscillations through the generation of inositol 1,4,5-triphosphate (IP3), which causes Ca2+ release by binding to IP3 receptors located on the endoplasmic reticulum (ER) of the oocyte. Ability to respond to this activating stimulus develops during meiotic maturation of the oocyte. Here we examine how the development of this ability is perturbed when a single spermatozoon is introduced into the oocyte prematurely, i.e. during oocyte maturation. Results Mouse oocytes during maturation in vitro were fertilised by ICSI (intracytoplasmic sperm injection) 1 – 4 h after germinal vesicle break-down (GVBD) and were subsequently cultured until they reached metaphase II (MII) stage. At MII stage they were fertilised in vitro for the second time (refertilisation). We observed that refertilised oocytes underwent activation with similar frequency as control oocytes, which also went through maturation in vitro, but were fertilised only once at MII stage (87% and 93%, respectively). Refertilised MII oocytes were able to develop [Ca2+]i oscillations in response to penetration by spermatozoa. We found however, that they generated a lower number of transients than control oocytes. We also showed that the oocytes, which were fertilised during maturation had a similar level of MPF activity as control oocytes, which were not subjected to ICSI during maturation, but had reduced level of IP3 receptors. Conclusion Mouse oocytes, which were experimentally fertilised during maturation retain the ability to generate repetitive [Ca2+]i transients, and to be activated after completion of maturation.

Jedrusik, Agnieszka; Ajduk, Anna; Pomorski, Pawel; Maleszewski, Marek

2007-01-01

61

A comparison between oocyte growth in coculture with granu- losa cells and oocytes with granulosa cell-oocyte junctional contact maintained in vitro  

Microsoft Academic Search

Evidence is presented that strongly supports the hypothesis that the junctional association between oocytes and granulosa cells must be maintained to promote oocyte growth and development in vitro and that the coculture of oocytes with granulosa cells is not a sufficient condition for oocyte development. Furthermore, it is shown that incorporation of uridine and leucine by oocytes into TCA-insoluble material

John J. Eppig

1979-01-01

62

How is plasminogen/plasmin system contributing to regulate sperm entry into the oocyte?  

PubMed

Plasminogen is present in the oviduct, on the zona pellucida (ZP) and on oolemma, and reduces the number of sperm penetrating the oocyte during in vitro fertilization in pig and cow. It is unknown how this reduction occurs. We tested whether plasminogen (1) changed the ZP resistance to enzymatic digestion thus making the passage of the spermatozoa across it difficult; (2) reduced the sperm functionality, assessed by sperm viability, motility, spontaneous acrosome reaction and membrane lipid disorder; or (3) affected the sperm-ZP binding before or after sperm-ZP interaction. The mechanism by which plasminogen/plasmin system contributes to regulate sperm entry into the oocyte is not inducing a ZP hardening or a decrease in sperm functionality but detaching more than 50% of sperm bound to the ZP. It is suggested that the fertilizing spermatozoon activates plasminogen into plasmin at the oocyte surface and that plasmin removes additional spermatozoa attached to the ZP. PMID:23420828

Grullón, Luis A; Gadea, Joaquín; Mondéjar, Irene; Matás, Carmen; Romar, Raquel; Coy, Pilar

2013-02-18

63

Selected Topics in Laboratory Animal Medicine. Volume XXIV. The Hamster.  

National Technical Information Service (NTIS)

This review discusses pertinent aspects of the use, care, and management of the hamster in the biomedical research environment. It is primarily concerned with the Syrian (golden) hamster (Mesocricetus auratus) and to a lesser extent the Chinese hamster (C...

R. E. Schmidt

1975-01-01

64

In vitro maturation and fertilization of porcine oocytes after a 48 h culture in roscovitine, an inhibitor of p34cdc2/cyclin B kinase.  

PubMed

Maintaining oocytes at the germinal vesicle (GV) stage in vitro may permit enhanced acquisition of the developmental competence. The objective of the current study was to evaluate the nuclear and cytoplasmic maturation in vitro of porcine oocytes after pretreatment with S-roscovitine (ROS). Cumulus oocyte complexes (COC) were treated with 50 microM ROS for 48 h and then matured for various lengths of time in a conventional step-wise in vitro maturation (IVM) system by using dibutyryl cyclic AMP. The COC that were matured in the same system for 44 h without pretreatment with ROS were used as the control group. At various periods after the start of IVM, oocytes were assessed for the meiotic stages and subjected to in vitro fertilization (IVF) with fresh spermatozoa. The ROS treatment inhibited GV breakdown of 94.4% oocytes, with the majority arrested at the GV-I stage (67.4%). Maximum maturation rate to the metaphase-II stage after ROS treatment was achieved by 44 h of IVM (92.1%) and no differences were observed with control oocytes (95.0%). Penetration rate was correlated to the maturation rate. The duration of IVM had no effects on polyspermy and male pronuclear (MPN) formation rates at 8 h post insemination (hpi), whereas both rates increased at 22 hpi. Direct comparison with controls assessed at 22 hpi confirmed a lesser MPN formation in ROS-treated oocytes (73.7% compared with 53.6%). Glutathione (GSH) concentrations were less in oocytes treated with ROS than in control oocytes (5 compared with 7.7 pmol/oocyte) as well as blastocyst rate (22.0% compared with 38.1%, respectively). These results demonstrate that cytoplasmic maturation in porcine oocytes pretreated with ROS for 48 h did not equal that of control oocytes in the current IVM system. PMID:16054783

Romar, Raquel; Funahashi, Hiroaki

2005-07-28

65

The extracellular matrix of porcine mature oocytes: Origin, composition and presumptive roles  

PubMed Central

The extracellular matrix (ECM) of porcine mature oocytes was revealed by transmission electron microscopy (TEM) after treatment with tannic acid and ruthenium red. Present in the perivitelline space (PVS) and on the surface of the zona pellucida (ZP), it appeared to be composed of thin filaments and granules at the interconnections of the filaments, which were interpreted respectively as hyaluronic acid chains and bound proteoglycans. In order to determine whether this material is produced by the corona cells (the same ECM was found also on the surface of the zona pellucida and between cumulus cells) or by the oocyte itself, the synthesis of glycoproteins and glycosaminoglycans was checked by autoradiography on semi-thin and thin sections observed by light and electron microscopy. Immature oocytes within or without cumulus cells, were incubated with L [3H-] fucose or L [3H-] glucosamine – precursors respectively of glycoproteins and hyaluronic acid or hyaluronan (HA) bound to proteoglycans – for various times (with or without chase) and at different stages during in vitro maturation. In the first case, incorporation was found in both cumulus cells and ooplasm (notably in the Golgi area for 3H-fucose) and labeled material accumulated in the ECM of the PVS and of the ZP surface. Labeling in the PVS with both precursors was maximum between metaphase I (MI) and metaphase II (MII) and was partially extracted by hyaluronidase but not by neuraminidase. Tunicamycin, an inhibitor of glycoprotein synthesis, significantly decreased the amount of 3H-fucose labeled molecules in the PVS and increased the incidence of polyspermic penetration during subsequent in vivo fertilization. Since cumulus-free oocytes also secreted 3H-glucosamine containing compounds, both oocyte and cumulus cells probably contribute to the production of the ECM found in the PVS of mature oocytes. ECM and particularly its HA moiety present on both sides of the ZP may constitute a favourable factor for sperm penetration.

Flechon, Jacques E; Degrouard, Jeril; Kopecny, Vaclav; Pivko, Juraj; Pavlok, Antonin; Motlik, Jan

2003-01-01

66

Serotoninergic System in Hamster Skin  

Microsoft Academic Search

We have cloned the tryptophan hydroxylase cDNA from hamster pituitary and demonstrated its expression in the skin, melanotic and amelanotic melanomas, spleen, heart, and the eye. We further demonstrated that skin, melanomas, spleen, pituitary, and eye but not heart expressed arylalkylamine N-acetyltransferase mRNA. The cutaneous expression of the arylalkylamine N-acetyltransferase gene was accompanied by enzymatic activity for the conversion of

Andrzej Slominski; Alexander Pisarchik; Igor Semak; Trevor Sweatman; Andre Szczesniewski; Jacobo Wortsman

2002-01-01

67

Calcium signaling in Xenopus oocyte.  

PubMed

Knowledge about calcium signaling had increased thanks to the development and manipulation of various cell models. Among all of these prototypes, Xenopus laevis oocyte appears to be one of the most relevant. The understanding of the role of calcium during oocyte oogenesis, maturation and fertilization is facilitated by the big size of the cell but also by using imaging and electrophysiological approaches. So, this chapter presents how recordings of calcium-activated chloride channels and Store-Operated Calcium Channels activities lead to demonstrate the implication of the MPF in the uncoupling between intracellular calcium releasing and capacitative calcium entry. Moreover, it will help us to understand the several reorganizations happening consequently to the pH variations of maturation or just at the moment of fertilization. PMID:22453984

Marin, Matthieu

2012-01-01

68

Transplantation of nuclei from growing oocytes into fully grown enucleated sturgeon oocytes.  

PubMed

Experiments involving enucleation of oocytes and transplantation of germinal vesicles showed that, at the start of the period of greatest growth, the oocyte caryoplasm already contains the substances necessary to make the cytoplasm capable of cytotomy. PMID:1124435

Nikitina, L A

1975-05-01

69

Successful Cryopreservation of Mouse Oocytes by Using Low Concentrations of Trehalose and Dimethylsulfoxide1  

PubMed Central

Sugars such as trehalose, sucrose, and glucose are effectively used by a variety of animals (e.g., brine shrimp, tardigrades, some frogs, and insects), as well as by bacteria, yeasts, and plant seeds to survive freezing and extreme drying. The objective of this study was to examine the potential application of sugars to mammalian oocyte cryopreservation. To this end, we used trehalose, a nonreducing disaccharide, and mouse metaphase II oocytes as models. Our experiments show that extracellular trehalose alone affords some protection at high subzero temperatures (e.g., ?15°C), which diminishes with further cooling of the oocytes to ?30°C and below. When present both intracellularly and extracellularly, trehalose dramatically improves the cryosurvival with increasing extracellular concentrations to 0.5 M, even after cooling to ?196°C. Furthermore, the combination of intracellular and extracellular trehalose with small amounts of a conventional penetrating cryoprotectant (i.e., 0.5 M dimethylsulfoxide) provide high survival, fertilization, and embryonic development rates statistically similar to untreated controls. When transferred to foster mothers, cryopreserved oocytes give rise to healthy offspring showing the proof of principle. Our experiments with differential scanning calorimetry indicate that when cooled using the same cryopreservation protocol, the mixture of 0.5 M trehalose and cryopreservation medium undergoes glass transition at high subzero temperatures, which further substantiates the use of sugars as intracellular and extracellular cryoprotectants. Taken together, our results are in agreement with the survival schemes in nature and demonstrate the successful use of sugars in cryopreservation of mammalian oocytes.

Eroglu, Ali; Bailey, Sarah E.; Toner, Mehmet; Toth, Thomas L.

2008-01-01

70

Meiotic recombination in human oocytes.  

PubMed

Studies of human trisomies indicate a remarkable relationship between abnormal meiotic recombination and subsequent nondisjunction at maternal meiosis I or II. Specifically, failure to recombine or recombination events located either too near to or too far from the centromere have been linked to the origin of human trisomies. It should be possible to identify these abnormal crossover configurations by using immunofluorescence methodology to directly examine the meiotic recombination process in the human female. Accordingly, we initiated studies of crossover-associated proteins (e.g., MLH1) in human fetal oocytes to analyze their number and distribution on nondisjunction-prone human chromosomes and, more generally, to characterize genome-wide levels of recombination in the human female. Our analyses indicate that the number of MLH1 foci is lower than predicted from genetic linkage analysis, but its localization pattern conforms to that expected for a crossover-associated protein. In studies of individual chromosomes, our observations provide evidence for the presence of "vulnerable" crossover configurations in the fetal oocyte, consistent with the idea that these are subsequently translated into nondisjunctional events in the adult oocyte. PMID:19763179

Cheng, Edith Y; Hunt, Patricia A; Naluai-Cecchini, Theresa A; Fligner, Corrine L; Fujimoto, Victor Y; Pasternack, Tanya L; Schwartz, Jackie M; Steinauer, Jody E; Woodruff, Tracey J; Cherry, Sheila M; Hansen, Terah A; Vallente, Rhea U; Broman, Karl W; Hassold, Terry J

2009-09-18

71

Oocyte growth in vitro: potential model for studies of oocyte–granulosa cell interactions  

Microsoft Academic Search

Various factors such as gonadotrophins, growth factors, and steroid hormones play important roles in the regulation of oocyte\\/follicular\\u000a growth in mammalian ovaries. In addition to these factors, there is a bidirectional interaction between oocytes and granulosa\\u000a cells that is essential for achieving optimal oocyte developmental competence. Oocytes play a key role in this interaction\\u000a by secreting paracrine factors that alter

Yuji Hirao

72

Reconstruction of mouse oocytes by germinal vesicle transfer: maturity of host oocyte cytoplasm determines meiosis  

Microsoft Academic Search

We evaluated the maturational competence of mouse oocytes reconstructed by the transfer and electrofusion of germinal vesicles (GV) into anuclear cytoplasts of GV stage oocytes (both auto- and hetero-transfers), metaphase II stage oocytes or zygotes. Following in-vitro culture, the maturation rates of the reconstructed oocytes to metaphase II did not significantly differ between auto- and hetero- transfers (40\\/70 versus 95\\/144

Hui Liu; Chia-Woei Wang; James A. Grifo; Lewis C. Krey; John Zhang

73

Oocyte transport: Developmental competence of bovine oocytes arrested at germinal vesicle stage by cycloheximide under air.  

PubMed

The effects of the medium (TCM 199 or SOFaa) and temperature (20 or 39 C) during meiotic arrest by cycloheximide (CHX) under air on the developmental competence of bovine oocytes after in vitro maturation (IVM) and fertilization (IVF) were investigated. Oocytes were maintained in meiotic arrest by 10 microg/ml CHX in a 50-microl droplet of 25-mM HEPES-buffered TCM 199 (H199) at 39 C or synthetic oviduct fluid (HSOFaa) at 20 or 39 C in air for 24 h. After release from the arrest, the oocytes was matured and fertilized in vitro and their developmental competence was examined. The developmental rate of oocytes arrested in HSOFaa at 20 C to the blastocyst stage was similar to that of non-arrested oocytes but was significantly higher (P<0.05) than that of oocytes arrested at 39 C in H199 or in HSOFaa. In consideration of oocyte transport conditions, we also investigated the meiotic arrest of oocytes maintained in a 0.25-ml straw by CHX individually with 10 microl HSOFaa or as a group (40-50 oocytes) with 170-200 microl HSOFaa at 20 C in air for 24 h. After release from meiotic arrest, the developmental competence of these oocytes was assessed similarly. The developmental rate of oocytes treated with CHX individually was similar to that of those treated with CHX in 50-microl droplet of HSOFaa at 20 C. However, the developmental rate of oocytes treated with CHX as a group was lower than that of oocytes treated with CHX in a 50-microl droplet. Five blastocysts developed from oocytes maintained in meiotic arrest in a plastic straw were transferred to five recipient heifers. Consequently, three recipients became pregnant and 2 calves were delivered. The results of the present study indicate that bovine oocytes treated with CHX in HSOFaa at 20 C under air retain the same developmental competence as non-arrested oocytes. PMID:14967950

Hashimoto, Shu; Kimura, Kouji; Iwata, Hisataka; Takakura, Ryo

2003-02-01

74

Metaphase II karyoplast transfer from human in-vitro matured oocytes to enucleated mature oocytes.  

PubMed

Metaphase II karyoplast transfer is believed to be a useful method to rescue aged oocytes. This study attempted karyoplast transfer of in-vitro matured metaphase II (MII) oocytes, as a model of aged oocytes, into enucleated freshly ovulated metaphase II oocytes with visualization of their chromosomes under an inverted microscope. Recipient karyoplasts derived from immature oocytes were cultured in-vitro until first polar body extrusion. After 1-2 days culture, 52.1% extruded a polar body, 95.5% had PSC, aneuploidy was very low (4.5%) and none had structural aberrations. Donor oocytes were obtained from IVF or intracytoplasmic sperm injection (ICSI) patients. Chromosomes were easily confirmed in 92.3% and 95.0% of in-vivo and in-vitro matured oocytes respectively. Thirty-one karyoplasts were placed in the perivitelline space of enucleated donor oocytes, and 25 (80.6%) fused to form a reconstituted oocyte. Fertilization, cleavage and blastocyst formation rates following ICSI were 76.0%, 64.0% and 28.0% respectively for reconstructed oocytes and 59.2%, 48.0% and 3.1% respectively for control (in-vitro matured) oocytes. Chromosomal analysis of five embryos developed after karyoplast transfer and ICSI showed normal diploid sets of 46 chromosomes. In conclusion, this metaphase II karyoplast transfer technique can be applied to the solution of chromosomal abnormalities related to oocyte ageing. PMID:19909592

Tanaka, Atsushi; Nagayoshi, Motoi; Awata, Shoichiro; Himeno, Norio; Tanaka, Izumi; Watanabe, Seiji; Kusunoki, Hiroshi

2009-10-01

75

Oocyte control of metabolic cooperativity between oocytes and companion granulosa cells: energy metabolism  

Microsoft Academic Search

Intercellular communication between oocytes and granulosa cells is essential for normal follicular differentiation and oocyte development. Subtraction hybridization was used to identify genes more highly expressed in cumulus cells than in mural granulosa cells of mouse antral follicles. This screen identified six genes involved in glycolysis: Eno1, Pkm2, Tpi, Aldoa, Ldh1, and Pfkp. When oocytes were microsurgically removed from cumulus

Koji Sugiura; Frank L. Pendola; John J. Eppig

2005-01-01

76

NMR observation of Tau in Xenopus oocytes  

NASA Astrophysics Data System (ADS)

The observation by NMR spectroscopy of microinjected 15N-labelled proteins into Xenopus laevis oocytes might open the way to link structural and cellular biology. We show here that embedding the oocytes into a 20% Ficoll solution maintains their structural integrity over extended periods of time, allowing for the detection of nearly physiological protein concentrations. We use these novel conditions to study the neuronal Tau protein inside the oocytes. Spectral reproducibility and careful comparison of the spectra of Tau before and after cell homogenization is presented. When injecting Tau protein into immature oocytes, we show that both its microtubule association and different phosphorylation events can be detected.

Bodart, Jean-François; Wieruszeski, Jean-Michel; Amniai, Laziza; Leroy, Arnaud; Landrieu, Isabelle; Rousseau-Lescuyer, Arlette; Vilain, Jean-Pierre; Lippens, Guy

2008-06-01

77

Pluripotent stem cells from maturing oocytes.  

PubMed

Abstract Embryonic stem cells are mostly derived from mature oocytes that were either fertilized or activated parthenogenetically and then reached the blastocyst stage. From the cell cycle perspective, fertilization or activation induces the exit from meiosis, decondensation of oocyte chromosomes, and the entry into mitosis. Decondensation of oocyte chromatin with subsequent formation of nuclei can be, however, induced at any postgerminal vesicle breakdown meiotic maturation stage. In this article, we discuss the possibility of cleavage of transformed maturing oocytes and whether they can reach the blastocyst stage, from which pluripotent stem cell lines could be derived. PMID:23961764

Langerova, Alena; Fulka, Helena; Fulka, Josef

2013-08-20

78

[Oocyte vitrification in an ART laboratory].  

PubMed

Oocyte vitrification has been authorized in France after the modification of French bioethics law in July 2011. This evolution will bring a dramatic change in patients' management since, from 2011, infertile couples, oocyte donation and fertility preservation programs will benefit this technique in France. We have introduced oocyte vitrification in our ART laboratory through a validation of the method using Evidence-Based Medicine model: open system Cryotop, Ethylène-glycol 15% and DMSO 15%. Based on our 1-year experience, oocyte vitrification upgrades our daily practice while also minimizing embryo cryoconservation as recommended by the law. PMID:23969289

Boyer, P; Montjean, D; Tourame, P; Gervoise-Boyer, M

2013-08-20

79

Penetration of concrete targets  

SciTech Connect

We developed penetration equations for ogive-nosed projectiles that penetrated concrete targets after normal impact. Our penetration equations predict axial force on the projectile nose, rigid-body motion, and final penetration depth. For target constitutive models, we conducted triaxial material experiments to confining pressures of 600 MPa and curve-fit these data with a linear pressure-volumetric strain relation and with a linear Mohr-Coulomb, shear strength-pressure relation. To verify our penetration equations, we conducted eleven penetration experiments with 0.90 kg, 26.9-mm-diameter, ogive-nosed projectiles into 1.37-m-diameter concrete targets with unconfined compressive strengths between 32-40 MPa. Predictions from our penetration equation are compared with final penetration depth measurements for striking velocities between 280--800 m/s.

Forrestal, M.J. [Sandia National Labs., Albuquerque, NM (United States); Cargile, J.D. [Corps of Engineers, Vicksburg, MS (United States). Waterways Experiment Station; Tzou, R.D.Y. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Mechanical Engineering

1993-08-01

80

FATE OF INHALED FLY ASH IN HAMSTERS  

EPA Science Inventory

To determine pulmonary deposition, translocation, and clearance of inhaled fly ash, hamsters received a single 95-min nose-only exposure to neutron-activated fly ash. Over a period of 99 days postexposure, the hamsters were sacrificed in groups of six animals. Lungs, liver, kidne...

81

Directed Student Inquiry: Modeling in Roborovsky Hamsters  

ERIC Educational Resources Information Center

|In this inquiry-based activity, Roborovsky hamsters are used to provide students with an opportunity to develop their skills of analysis, inquiry, and design. These hamsters are easy to maintain, yet offer students a means to use conventional techniques and those of their own design to make further observations through measuring, assessing, and…

Elwess, Nancy L.; Bouchard, Adam

2007-01-01

82

Nonphotic Phase Shifting in Hamster Clock Mutants  

Microsoft Academic Search

Golden hamsters with the tau mutation were kept in the dark and induced to become active through confinement to a novel running wheel for 3 hr. The response of the mutants to this nonphotic phase-shifting stimulus differed from that of wild-type hamsters. The mutants showed larger phase shifts, and their phase response curves differed in shape, with an advance portion

N. Mrosovsky; Peggy A. Salmon; Michael Menaker; Martin R. Ralph

1992-01-01

83

Anthrax vaccine efficacy in golden Syrian hamsters  

Microsoft Academic Search

The efficacy of a licensed human anthrax vaccine (anthrax vaccine adsorbed, AVA) was tested in golden Syrian hamsters against a virulent Bacillus anthracis spore challenge. Groups of golden Syrian hamsters were vaccinated at either 0 and 4 weeks or 0, 4 and 8 weeks, then challenged subcutaneously (s.c.) at 10 weeks with spores of various B. anthracis isolates. Although ELISA

P. F Fellows; M. K Linscott; S. F Little; P Gibbs; B. E Ivins

2002-01-01

84

Penetration I Berg (Penetration in Rock Materials).  

National Technical Information Service (NTIS)

A study has been carried out on the penetration capability of slender and undeforming long rod projectiles into granite and limestone. The study has consisted of an experimental part where model scale heavy metal projectiles have been fired at velocities ...

P. Lundberg R. Renstroem L. Westerling

1997-01-01

85

Laboratory evaluation in oocyte cryopreservation suggests retrieved oocytes are comparable whether frozen for medical indications, deferred reproduction or oocyte donation  

PubMed Central

Purpose To compare pre-cryo data from oocyte cryopreservation (OC) cycles performed for malignancy (MED) vs. elective deferment of reproduction (DR) or oocyte donation (OD). Methods All patients were ?40 y and underwent standard ovarian stimulation and retrieval. Prior to OC, meiotic spindle (MS) and zona pellucida (ZP) retardance was measured using digital polarized light microscopy (DPLM). Results Of 130 OC cycles, 49 were for MED, 73 for DR, and 8 for OD. Cycles completed for MED had an average of 9?±?1 spindle-positive oocytes with a mean MS retardance of 1.2?±?.02 nm and ZP retardance of 2.1?±?.06 nm, which was clinically comparable to the other groups. Conclusions Women with malignancy can achieve adequate ovarian response and similar oocyte parameters to those of women undergoing fertility preservation for non-cancer indications. Such information, coupled with the ability to noninvasively study oocyte dynamics, may improve the counseling of cancer patients seeking fertility preservation.

Werner, Marie; Reh, Andrea; Labella, Patty Ann

2010-01-01

86

Improvement in bovine embryo production in vitro by treatment with green tea polyphenols during in vitro maturation of oocytes.  

PubMed

The present study examined the effect of green tea polyphenols (GTP) during in vitro maturation (IVM) of bovine oocytes on in vitro fertilization (IVF) parameters, intracellular glutathione (GSH) concentration and subsequent embryo development. Cumulus-oocyte complexes were aspirated from the ovaries derived from slaughterhouse and cultured in modified synthetic oviduct fluid (m-SOF) supplemented with 0-25 microM GTP for 24h. After IVM, cumulus-free oocytes were coincubated with frozen-thawed spermatozoa for 15-18 h. Putative embryos were transferred to m-SOF and cultured for 8 days (Experiment 1). In comparison with the absence of GTP, treatment with GTP at a concentration of 15 microM showed a significant increase in the proportion of pronuclear (PN) formation after sperm penetration (65% versus 80%, P<0.05). No significant differences in the rates of sperm penetration and polyspermic fertilization were found among treatments. The cleavage rate at 48 h of in vitro insemination showed no difference in oocytes matured with or without GTP. However, compared to no addition (23.5%), the presence of 15 and 20 microM GTP during IVM significantly (P<0.05) increased the proportion of blastocysts (38.1% and 36.4%) on day 9 of in vitro insemination. A further increase from 20 to 25 microM GTP reduced (P<0.05) the proportion of blastocysts. In Experiment 2, after IVM, oocytes were fixed to analyze the GSH concentration. Compared to no addition, a higher (P<0.05) level of GSH was found in oocytes matured with 15 microM GTP and compared with 15 microM GTP, GSH was low (P<0.05) at 20 and 25 microM GTP. The results suggest that at certain concentrations of GTP (15 microM) in IVM medium has beneficial effects on subsequent embryo development, and is correlated with intracellular GSH level in bovine oocytes. PMID:16870363

Wang, Zheng-guang; Yu, Song-dong; Xu, Zi-rong

2006-07-25

87

Swimming stimulates oocyte development in European eel  

Microsoft Academic Search

In this study, we subjected eels from Lake Balaton (Hungary) to a swimming period of 1 week and 2 or 6 weeks. Most eels were silver and were 13–21 years old. Time dependent changes in morphometrical parameters and developmental characteristics of the oocytes were determined. Already after 1 week of swimming, the gonadal mass increased and oocytes became larger, filled with large

Arjan Palstra; Danilo Curiel; Madelon Fekkes; Merijn de Bakker; Csaba Székely; Vincent van Ginneken; Guido van den Thillart

2007-01-01

88

Polycystic Ovary Syndrome and Oocyte Developmental Competence  

PubMed Central

Folliculogenesis is a complex process, in which multiple endocrine and intraovarian paracrine interactions create a changing intrafollicular microenvironment for appropriate oocyte development. Within this microenvironment, bidirectional cumulus cell-oocyte signaling governs the gradual acquisition of developmental competence by the oocyte, defined as the ability of the oocyte to complete meiosis and undergo fertilization, embryogenesis and term development. These regulatory mechanisms of follicle growth, controlled in part by the oocyte itself, are susceptible to derangement in polycystic ovary syndrome (PCOS), a heterogeneous syndrome characterized by ovarian hyperandrogenism, insulin resistance and paracrine dysregulation of follicle development. Consequently only a subset of PCOS patients experience reduced pregnancy outcome following ovarian stimulation for in vitro fertilization (IVF). Recent data implicate functional associations between endocrine/paracrine abnormalities, metabolic dysfunction and altered oocyte gene expression with impaired oocyte developmental competence in women with PCOS. Therefore, an understanding of how developmentally relevant endocrine/paracrine factors interact to promote optimal oocyte developmental is crucial to identify those PCOS patients who might benefit from long-term correction of follicle growth to improve fertility, optimize follicular responsiveness to gonadotropin therapy and enhance pregnancy outcome by IVF.

Dumesic, Daniel A.; Padmanabhan, Vasantha; Abbott, David H.

2009-01-01

89

Running wheel choice by Syrian hamsters.  

PubMed

The present study investigated the preference of male and female Syrian hamsters, Mesocricetus auratus, for different types of running wheels. Hamsters were placed individually in sets of multiple cages linked by tunnels, each cage with a different running wheel. The number of wheel revolutions in each cage was tallied daily over 40 days. The hamsters did not express a preference when offered a choice of a running surface made of metal rods spaced 9 mm apart and a similar running surface covered in plastic mesh to prevent the possible slippage of feet between the rods. The hamsters did express a clear preference for larger wheels (35 versus 23 cm diameter), and for completely circular wheels over truncated ones. They neither favoured nor rejected wheels with small obstacles along the running surface. In all experiments, preferences were more strongly expressed by males than by females. Running wheels for hamsters may be improved by enlarging their diameter (to the standards often used for rats, if practically possible) and by ensuring good footing on the running surface (a space no larger than 9 mm between evenly spaced rods seems sufficient to achieve this, at least in large wheels and for hamsters older than 55 days). Installing obstacles along the running surface does not appear to make the wheel more interesting to hamsters. PMID:16197712

Reebs, S G; St-Onge, P

2005-10-01

90

A scaffold for the Chinese hamster genome.  

PubMed

Chinese hamster ovary (CHO) cells are a prevalent tool in biological research and are among the most widely used host cell lines for production of recombinant therapeutic proteins. While research in other organisms has been revolutionized through the development of DNA sequence-based tools, the lack of comparable genomic resources for the Chinese hamster has impeded similar work in CHO cell lines. A comparative genomics approach, based upon the completely sequenced mouse genome, can facilitate genomic work in this important organism. Using chromosome synteny to define regions of conserved linkage between Chinese hamster and mouse chromosomes, a working scaffold for the Chinese hamster genome has been developed. Mapping CHO and Chinese hamster sequences to the mouse genome creates direct access to relevant information in public databases. Additionally, mapping gene expression data onto a chromosome scaffold affords the ability to interpret information in a genomic context, potentially revealing important structural and regulatory features in the Chinese hamster genome. Further development of this genomic scaffold will provide opportunities to use biomolecular tools for research in CHO cell lines today and will be an asset to future efforts to sequence the Chinese hamster genome. PMID:17390381

Wlaschin, Katie F; Hu, Wei-Shou

2007-10-01

91

Species differences in the effect of benzo(alpha)pyrene-ferric oxide on the respiratory tract of rats and hamsters.  

PubMed

When given intratracheal injections of a suspension of benzo(alpha)pyrene-ferric oxide, rats and hamsters showed striking species differences in the response of their respiratory tracts to the carcinogen. Hamsters produced squamous metaplasia of the trachea and large bronchi; in contrast, squamous cell nodules of bronchioloalveolar origin developed in rats within a few weeks after carcinogen application. The different sites of the early proliferative and metaplastic responses correlated in their location with the sites of later tumor development. There were no obvious differences between the two species in retention of benzo(alpha)pyrene in the lungs or tracheas. A species difference was observed, however, in the localization of the benzo(alpha)pyrene in the tracheal tissues using ultraviolet fluorescence microscopy. Carcinogen was found to be present in the epithelium of hamsters but not in the epithelium of rats, suggesting a species difference in penetration of carcinogen from the lumen into the tracheal tissues. PMID:1131827

Schreiber, H; Martin, D H; Pazmiño, N

1975-07-01

92

A Miniature Probe for Ultrasonic Penetration of a Single Cell  

PubMed Central

Although ultrasound cavitation must be avoided for safe diagnostic applications, the ability of ultrasound to disrupt cell membranes has taken on increasing significance as a method to facilitate drug and gene delivery. A new ultrasonic resonance driving method is introduced to penetrate rigid wall plant cells or oocytes with springy cell membranes. When a reasonable design is created, ultrasound can gather energy and increase the amplitude factor. Ultrasonic penetration enables exogenous materials to enter cells without damaging them by utilizing instant acceleration. This paper seeks to develop a miniature ultrasonic probe experiment system for cell penetration. A miniature ultrasonic probe is designed and optimized using the Precise Four Terminal Network Method and Finite Element Method (FEM) and an ultrasonic generator to drive the probe is designed. The system was able to successfully puncture a single fish cell.

Wu, Ting; Zhou, Zhaoying; Wang, Qun; Yang, Xing; Xiao, Mingfei

2009-01-01

93

Noninvasive bovine oocyte quality assessment: possibilities of a single oocyte culture.  

PubMed

Although bovine embryos are routinely produced in vitro for several decades, there still exists a critical need for techniques to accurately predict the oocyte's developmental competence in a noninvasive way, before the in vitro embryo production procedure. In this review, several noninvasive methods to evaluate oocyte quality are discussed, such as morphological assessment of the cumulus oocyte complex and the use of brilliant cresyl blue. Because an individual oocyte and embryo culture method can possibly generate additional insights into the factors that determine oocyte quality, the second part of this review summarizes the state of the art of bovine single oocyte culture. The optimization of individual in vitro embryo production can obviously accelerate the quest for better noninvasive oocyte quality markers, because more information about the oocyte's requirements and intrinsic quality will be revealed. Although each step of in vitro culture has to be re-examined in light of the hampered production of single embryos, the reward at the end will be substantial. Individual scored oocytes will be traceable along the in vitro embryo production procedure and the final blastocyst outcome can be linked to the original oocyte quality and follicular environment without the bias caused by simultaneously developing embryos. PMID:20708251

Goovaerts, I G F; Leroy, J L M R; Jorssen, E P A; Bols, P E J

2010-08-12

94

Caffeine and dithiothreitol delay ovine oocyte ageing.  

PubMed

The intracellular glutathione levels and developmental competence of aged oocytes after parthenogenetic activation, somatic cell nuclear transfer and intracytoplasmic sperm injection in the presence or absence of caffeine or dithiothreitol (DTT) were examined. The following results were found: (1) ovine oocytes were fully aged 30 h post-onset of maturation culture; (2) the appropriate concentrations of caffeine and DTT for oocyte culture were 5 mM and 1 mM, respectively; (3) when nuclear transfer-reconstructed embryos were treated with caffeine or DTT following fusion, no increase in the frequency of development to blastocyst was observed (P > 0.05), but the cell numbers of blastocysts increased (P < 0.05); (4) both caffeine and DTT increased the blastocyst formation rates of intracytoplasmic sperm-injected embryos (P < 0.05); (5) caffeine increased the glutathione content of aged oocytes (P < 0.05). The glutathione content of DTT-treated aged oocytes was higher than that of oocytes matured for 36 h (P < 0.05). In conclusion, caffeine and dithiothreitol delay oocyte ageing but only to a limited extent. PMID:20883651

Ye, Xiao-Fang; Chen, Shi-Bin; Wang, Li-Qin; Zhao, Yun-Cheng; Lv, Xue-Feng; Liu, Ming-Jun; Huang, Jun-Cheng

2010-01-01

95

An improved mouse sperm-oocyte plasmalemma binding assay: studies on characteristics of sperm binding in medium with or without glucose.  

PubMed

Sperm binding to the oocyte plasmalemma is crucial to subsequent steps in fertilization. However, the usual in vitro assay for sperm-oocyte binding does not distinguish between nonspecific attachment and specific binding leading to fusion and penetration. Since zona pellucida-free pronuclear zygotes should not bind sperm (because of the block to polyspermy at the level of the oocyte membrane), a procedure has been developed to remove virtually all sperm from zona-free pronuclear zygotes (2PNZ). After six washes with a 90-microm-bore pipette, there were 0.5 +/- 0.2 sperm/2PNZ (n = 83). Therefore, these washing conditions were used to define sperm-oocyte binding. The relationship of binding to oocyte penetration was determined for outbred mouse oocytes coincubated in complete medium with (B6 x 129)F1 hybrid sperm (10(7)/ml). Binding was maximal (29 +/- 5 sperm per oocyte) during the first 30 minutes but decreased significantly to 4.6 +/- 1.4 by 60 minutes of coincubation (over 10 trials). Oocyte penetration was 99 +/- 1% by 30 minutes, while the number of decondensed sperm nuclei per oocyte increased significantly to 7.5 +/- 0.6 at 60 minutes. These data suggest that the block to polyspermy involves detachment of bound sperm. Similar coincubations were carried out in medium without glucose (NoG), as this medium has been reported to inhibit fusion without affecting binding. However, binding was only 11 +/- 2 at 30 minutes but increased to 25 +/- 4 at 60 minutes, suggesting that binding was retarded in NoG. When gametes were coincubated in NoG for 5 hours, about half of the oocytes were penetrated, suggesting that the lack of glucose did not inhibit fusion but instead delayed it. These data suggest that if sperm binding is to be determined in complete medium, the time of the block to polyspermy should be determined prior to selecting the appropriate time to assay binding. Furthermore, using the same coincubation period for the binding assay in control and treated sperm may not be appropriate if the treatment alters the time of maximal binding. PMID:10452594

Redkar, A A; Olds-Clarke, P J

96

A new hamster model for adenoviral vaccination  

Microsoft Academic Search

Summary Both adult and baby hamsters infected intranasally with human adenovirus type 5 exhibited virologic, serologic, and histologic evidence of infection. When 8-day old hamsters were infected with 4×106 pfu, concentrations of virus up to 2×106 pfu\\/animal were detected in the lung, peaking on day 2. The minimum infectious dose was 1×103 pfu\\/animal. This model may be useful in studies

R. N. Hjorth; Geraldine M. Bonde; W. A. Pierzchala; S. K. Vernon; F. P. Wiener; M. H. Levner; M. D. Lubeck; P. P. Hung

1988-01-01

97

Testosterone self-administration in female hamsters  

Microsoft Academic Search

Abuse of anabolic-androgenic steroids (AAS) is a growing public health concern. In addition to their anabolic effects, steroids are also reinforcing as demonstrated by testosterone self-administration in male hamsters. However, steroid use in women lags behind that in men. Are androgens also rewarding in females? We determined if female hamsters voluntarily consume testosterone by intracerebroventricular (i.c.v.) self-administration in an operant

Jennifer L Triemstra; Ruth I Wood

2004-01-01

98

Directed Student Inquiry: Modeling in Roborovsky Hamsters  

NSDL National Science Digital Library

In this inquiry-based activity, Roborovsky hamsters are used to provide students with an opportunity to develop their skills of analysis, inquiry, and design. These hamsters are easy to maintain, yet offer students a means to use conventional techniques and those of their own design to make further observations through measuring, assessing, and data collection. Based on the premise that this is a directed rather than dictated student inquiry, the activity will vary based on discussions and recommendations suggested by each class.

Bouchard, Adam; Elwess, Nancy L.

2007-04-01

99

Session: Hard Rock Penetration  

SciTech Connect

This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hard Rock Penetration - Summary'' by George P. Tennyson, Jr.; ''Overview - Hard Rock Penetration'' by James C. Dunn; ''An Overview of Acoustic Telemetry'' by Douglas S. Drumheller; ''Lost Circulation Technology Development Status'' by David A. Glowka; ''Downhole Memory-Logging Tools'' by Peter Lysne.

Tennyson, George P. Jr.; Dunn, James C.; Drumheller, Douglas S.; Glowka, David A.; Lysne, Peter

1992-01-01

100

Oocyte glutathione and fertilisation outcome of Macaca nemestrina and Macaca fascicularis in in vivo- and in vitro-matured oocytes.  

PubMed

Fertilisation and development of IVM non-human primate oocytes is limited compared with that of in vivo-matured (IVO) oocytes. The present study describes the IVM of macaque oocytes with reference to oocyte glutathione (GSH). Timing of maturation, comparison of IVM media and cysteamine (CYS) supplementation as a modulator of GSH were investigated. A significantly greater proportion of oocytes reached MII after 30 h compared with 24 h of IVM. Following insemination, IVM oocytes had a significantly lower incidence of normal fertilisation (i.e. 2PN = two pronuclei and at least one polar body) and a higher rate of abnormal fertilisation (1PN = one pronucleus and at least one polar body) compared with IVO oocytes. Immunofluorescence of 1PN zygotes identified incomplete sperm head decondensation and failure of male pronucleus formation as the principal cause of abnormal fertilisation in IVM oocytes. The IVO oocytes had significantly higher GSH content than IVM oocytes. Cumulus-denuded oocytes had significantly lower GSH following IVM compared with immature oocytes at collection. Cysteamine supplementation of the IVM medium significantly increased the GSH level of cumulus-intact oocytes and reduced the incidence of 1PN formation, but did not improve GSH levels of the denuded oocyte. Suboptimal GSH levels in macaque IVM oocytes may be related to reduced fertilisation outcomes. PMID:20591337

Curnow, E C; Ryan, J P; Saunders, D M; Hayes, E S

2010-01-01

101

Glycolytic metabolites are critical modulators of oocyte maturation and viability.  

PubMed

The maturation of an oocyte into an egg is a key step in preparation for fertilization. In Xenopus, oocyte maturation is independent of transcription, being regulated at the level of translation and post-translational modifications of proteins. To identify factors involved in the maturation process we used two-dimensional differential gel electrophoresis to compare the proteome of oocytes and eggs. Protein abundance changes were observed in multiple cellular pathways during oocyte maturation. Most prominent was a general reduction in abundance of enzymes in the glycolytic pathway. Injection into oocytes of the glycolytic intermediates glyceraldehyde-3-phosphate, phosphoenolpyruvate and glucose-6-phosphate prevented oocyte maturation. Instead, these metabolites stimulated ROS production and subsequent apoptosis of the oocyte. In contrast, all other metabolites tested had no effect on oocyte maturation and did not induce apoptosis. These data suggest that a subset of glycolytic metabolites have the capacity to regulate oocyte viability. PMID:24167578

Berger, Lloyd; Wilde, Andrew

2013-10-22

102

Glycolytic Metabolites Are Critical Modulators of Oocyte Maturation and Viability  

PubMed Central

The maturation of an oocyte into an egg is a key step in preparation for fertilization. In Xenopus, oocyte maturation is independent of transcription, being regulated at the level of translation and post-translational modifications of proteins. To identify factors involved in the maturation process we used two-dimensional differential gel electrophoresis to compare the proteome of oocytes and eggs. Protein abundance changes were observed in multiple cellular pathways during oocyte maturation. Most prominent was a general reduction in abundance of enzymes in the glycolytic pathway. Injection into oocytes of the glycolytic intermediates glyceraldehyde-3-phosphate, phosphoenolpyruvate and glucose-6-phosphate prevented oocyte maturation. Instead, these metabolites stimulated ROS production and subsequent apoptosis of the oocyte. In contrast, all other metabolites tested had no effect on oocyte maturation and did not induce apoptosis. These data suggest that a subset of glycolytic metabolites have the capacity to regulate oocyte viability.

Berger, Lloyd; Wilde, Andrew

2013-01-01

103

Elastic and viscoelastic characterization of mouse oocytes using micropipette indentation.  

PubMed

This paper reports the first quantitative comparison study of elastic and viscoelastic properties of oocytes from young and aged mice. A force measurement technique, including a poly(dimethylsiloxane) (PDMS) cell holding device and a sub-pixel computer vision tracking algorithm, is utilized for measuring forces applied to an oocyte and resultant cell deformations in real time during oocyte manipulation. To characterize elastic and viscoelastic properties of the oocytes, a stress-relaxation indentation test is performed. A two-step, large-deformation mechanical model is developed to extract the mechanical properties of the oocytes from the measured force-deformation data. The experimental results demonstrate that the aged oocytes are significantly softer (instantaneous modulus: 2.2 vs. 5.2 kPa in young oocytes) but more viscous (relaxation time: 4.1 vs. 2.3 s in young oocytes) than the young oocytes. PMID:22644532

Liu, Xinyu; Shi, Jiayi; Zong, Zong; Wan, Kai-Tak; Sun, Yu

2012-05-30

104

Applications of cryopreserved unfertilized mouse oocytes for in vitro fertilization.  

PubMed

Since the first successful reports into oocyte freezing, many papers concerning the cryopreservation of mouse oocytes have been published. However, a simple and practical cryopreservation method for unfertilized C57BL/6 mouse oocytes, and an IVF system using these cryopreserved oocytes have yet to be established, in spite of the fact that C57BL/6 is the prevalent inbred strain and is used for large-scale knockout programs. In this study, unfertilized C57BL/6 mouse oocytes were cryopreserved via a simple vitrification method. After warming, IVF was performed using cryopreserved unfertilized oocytes and fresh sperm, cryopreserved unfertilized oocytes and cold-stored sperm, cryopreserved unfertilized oocytes and frozen sperm (C57BL/6 strain sperm), and cryopreserved unfertilized oocytes and frozen sperm derived from GEM strains (C57BL/6 background GEM strains). Nearly all of the cryopreserved oocytes were recovered, of which over 90% were morphologically normal. Those oocytes were then used for in vitro fertilization, resulting in 72-97% of oocytes developing into 2-cell embryos. A portion of the 2-cell embryos were transferred to recipients, resulting in live young being produced from 32-49% of the embryos. In summary, we established the simple and practical method of mouse oocyte vitrification with high survivability and developmental ability and the IVF using the vitrified-warmed oocytes with fresh, cold-stored or cryopreserved sperm with high fertility. PMID:23846105

Nakagata, Naomi; Takeo, Toru; Fukumoto, Kiyoko; Kondo, Tomoko; Haruguchi, Yukie; Takeshita, Yumi; Nakamuta, Yuko; Matsunaga, Hiroko; Tsuchiyama, Shuuji; Ishizuka, Yuta; Araki, Kimi

2013-07-08

105

[Abdominal penetrating trauma].  

PubMed

A 19-year-old female was brought to the Emergency Room as a trauma patient. During a tilting contest she fell off the horse and was penetrated by a spear used for tilting the ring. She was respiratorically as well as haemodynamically stable. The spear was supported but not removed by the paramedics. The spear penetrated the patient near the left iliac crest pointing at the heart. Further investigation at the Emergency Room is described briefly and guidelines for penetrating, impaled foreign bodies in the (thoraco)abdominal region are outlined. PMID:19671404

Kring, Søren; Helligsøe, Per; Kåg, Lise

2009-06-22

106

Artificial oocyte activation and human failed-matured oocyte vitrification followed by in vitro maturation.  

PubMed

The investigation presented in this paper was conducted on the effect of oocytes activation on frozen-thawed human immature oocytes followed by in vitro maturation (IVM). A total of 386 failed-matured oocytes (germinal vesicle (GV) and metaphase I (MI) stages) was randomly divided into two groups: fresh group and vitrification group, GV group and MI group, respectively). The matured oocytes were subject to intracytoplasmic sperm injection (ICSI) after IVM had been carried out. The vitrification group was randomly divided into two groups: controlled and artificial oocyte activation (AOA). The injected oocytes in the controlled group were cultured in cleavage medium. The AOA group oocytes were activated by exposing them to 7% anhydrous alcohol for 6 min then cultured in cleavage medium as well. The rates of fertilization and early embryonic development were compared between the controlled and AOA groups. In MI vitrification group, the high-quality embryo formation rate and blastocyst formation rate were significantly higher in the AOA group than in the controlled group (P < 0.01). In the GV vitrification group, the high-quality embryo formation rate was significantly higher in the AOA group than in the controlled group (P < 0.05). These results indicate that AOA may be good for early embryonic development of vitrified immature human oocytes. PMID:21867595

Liu, Y; Cao, Y X; Zhang, Z G; Xing, Q

2011-08-26

107

Mouse oocyte vitrification: the effects of two methods on maturing germinal vesicle breakdown oocytes  

PubMed Central

Purpose Evaluation of viability and subsequent developmental ability of mouse germinal vesicle breakdown oocytes vitrified in conventional straws. Methods Oocytes with compact cumulus cells were cultured for 3 h in TCM199 medium GVBD and vitrified by two methods: the step-wise and single-step. After vitrification, the oocytes were thawed, and subjected to in vitro maturation and in vitro fertilization. Oocyte survival (post-thaw) was assessed by morphological appearance and staining, using propidium iodide (PI)/Hoechst 33342. The oocyte maturation and fertilization rates were examined in vitro. Results In the single-step method the rates of post thaw survival, maturation to metaphase II and cleavage (2-cell embryos) were 58.68%, 56.41% and 38.63%, respectively. In the step-wise method, the corresponding rates were 81.75%, 68.59% and 51.80%, respectively. Conclusion Vitrification of mouse germinal vesicle breakdown oocytes by the step-wise method had the advantage of maintaining the viability and subsequent production of 2-cell embryos. In comparison with that in unvitrified control oocytes, the development of MII oocytes to 2-cell embryos was impaired following vitrification.

Khosravi-Farsani, Somayeh; Sobhani, Aligholi; Amidi, Fardin

2010-01-01

108

Successful piglet production by IVF of oocytes matured in vitro using NCSU-37 supplemented with fetal bovine serum.  

PubMed

Recently, piglets have been obtained from in vitro-produced blastocysts by using in vitro maturation systems in which oocytes have been matured in North Carolina State University (NCSU) solution supplemented with porcine follicular fluid (PFF). However, PFF is not available commercially. To prepare PFF from the ovaries required time and effort and there is substantial variation in quality among batches. Furthermore, PFF is considered a potential source of infectious agents. We evaluated another commercially available potential protein source, fetal bovine serum (FBS), for in vitro maturation, to produce embryos and piglets. Cumulus-oocyte complexes were matured in NCSU-37 with PFF or with one of four batches of FBS. The proportions of oocytes with expanded cumulus cells were lower in all FBS batch groups (P < 0.05, 15-41%) than that in the PFF group (74%). The proportions of oocytes that matured were also lower in all FBS batch groups (P < 0.05, 26-41%) than in the PFF group (73%), irrespective of cumulus expansion. However, the proportions of oocytes that underwent germinal vesicle breakdown were almost the same in all groups (76-96%). After in vitro fertilization, the rate of sperm penetration into matured oocytes was higher in the PFF group (P < 0.05, 63%) than in one batch of FBS (22%) and removal of the compacted cumulus cells after maturation did not affect fertilization status (21%). Subsequent in vitro embryo culture of the PFF and FBS groups for 6 day resulted in similar rates of blastocyst formation (17 and 19%, respectively) and similar numbers of cells per blastocyst (43 and 46 cells, respectively). When blastocysts obtained from oocytes matured with FBS were transferred into two recipients, one became pregnant and farrowed seven piglets. Transfer of blastocysts obtained from oocytes matured with PFF into two other recipients resulted in one pregnancy and production of four piglets. These data suggested that porcine in vitro maturation in NCSU-37 supplemented with FBS reduced the maturational ability of oocytes, but once oocytes have matured, they have the same ability to develop to term after in vitro fertilization and embryo transfer as those matured with PFF. PMID:15982730

Suzuki, Misae; Misumi, Koji; Ozawa, Manabu; Noguchi, Junko; Kaneko, Hiroyuki; Ohnuma, Katsuhiko; Fuchimoto, Dai-ichiro; Onishi, Akira; Iwamoto, Masaki; Saito, Norio; Nagai, Takashi; Kikuchi, Kazuhiro

2005-06-27

109

Hamsters Predisposed to Sucrose-Induced Cholesterol Gallstones (LPN Strain) Are More Resistant to Excess Dietary Cholesterol than Hamsters That Are Not Sensitive to Cholelithiasis Induction1  

Microsoft Academic Search

We compared the effects of cholesterol feeding in male hamsters from two strains with different propensities to sucrose-induced cholelithiasis; Laboratoire de Physiologie de la Nutrition (LPN) hamsters are predisposed to developing biliary cholesterol gallstones, whereas Janvier (JAN) hamsters are not. When fed a basal control diet, LPN hamsters had a lower cholesterolemia (221%, P 5 0.01) than JAN hamsters, and

Maamar Souidi; Murielle Combettes-Souverain; Erik R. Eckhardt; Olivier Audas; Sandrine Dubrac; Claude Lutton

110

Microencapsulated Fluorescent Dye Penetrant.  

National Technical Information Service (NTIS)

Microencapsulated fluorescent dye pentrant materials were evaluated for feasibility as a technique to detect cracks on metal surfaces when applied as a free flowing dry powder. Various flourescent dye solutions in addition to a commercial penetrant (Zyglo...

S. Allinikov

1979-01-01

111

Nuclear structures in Tribolium castaneum oocytes.  

PubMed

The first ultrastructural and immunomorphological characteristics of the karyosphere (karyosome) and extrachromosomal nuclear bodies in the red flour beetle, Tribolium castaneum, are presented. The karyosphere forms early in the diplotene stage of meiotic prophase by the gathering of all oocyte chromosomes in a limited nuclear volume. Using the BrUTP assay, T. castaneum oocyte chromosomes united in the karyosphere maintain their transcriptional activity until the end of oocyte growth. Hyperphosphorylated RNA polymerase II and basal transcription factors (TFIID and TFIIH) were detected in the perichromatin region of the karyosphere. The T. castaneum karyosphere has an extrachromosomal capsule that separates chromosomes from the rest of the nucleoplasm. Certain structural proteins (F-actin, lamin B) were found in the capsule. Unexpectedly, the karyosphere capsule in T. castaneum oocytes was found to be enriched in TMG-capped snRNAs, which suggests that the capsule is not only a structural support for the karyosphere, but may be involved in biogenesis of snRNPs. We also identified the counterparts of 'universal' extrachromosomal nuclear domains, Cajal bodies (CBs) and interchromatin granule clusters (IGCs). Nuclear bodies containing IGC marker protein SC35 display some features unusual for typical IGCs. SC35 domains in T. castaneum oocytes are predominantly fibrillar complex bodies that do not contain trimethyl guanosine (TMG)-capped small nuclear (sn) RNAs. Microinjections of 2'-O-methyl (U)22 probes into the oocytes allowed revealing poly(A)(+) RNAs in these nuclear domains. Several proteins related to mRNA export (heterogeneous ribonucleoprotein core protein A1, export adapters Y14 and Aly and export receptor NXF1) were also detected there. We believe that unusual SC35 nuclear domains of T. castaneum oocytes are possibly involved in mRNP but not snRNP biogenesis. PMID:23686847

Bogolyubov, Dmitry S; Batalova, Florina M; Kiselyov, Artyom M; Stepanova, Irina S

2013-06-24

112

Electrocardiographic changes in cardiomyopathic Syrian hamsters (strain BIO 8262)  

Microsoft Academic Search

Summary Under ether anesthesia electrocardiograms were derived from Syrian hamsters (strain BIO 8262) suffereing from cardiomyopathy and muscular dystrophy. In addition, ventricular weights and body weight were determined. Young hamsters-not yet showing morphological signs of the cardiomyopathy with the exception of possible left ventricular hypertrophy-demonstrated only a longer ventricular activation time than normal hamsters. With the onset of cardiac necrotization

K. Lossnitzer; N. Grewe; A. Konrad; J. Adler

1977-01-01

113

Histopathology of Lyme arthritis in LSH hamsters  

SciTech Connect

The authors studied the histopathologic evolution of arthritis in nonirradiated and irradiated hamsters infected with Borrelia burgdorferi. Nonirradiated hamsters injected in the hind paws with B. burgdorferi developed an acute inflammatory reaction involving the synovium, periarticular soft tissues, and dermis. This acute inflammatory reaction was short-lived and was replaced by a mild chronic synovitis as the number of detectable spirochetes in the synovium, periarticular soft tissues, and perineurovascular areas diminished. Exposing hamsters to radiation before inoculation with B. burgdorferi exacerbated and prolonged the acute inflammatory phase. Spirochetes also persisted longer in the periarticular soft tissues. A major histopathologic finding was destructive and erosive bone changes of the hind paws, which resulted in deformation of the joints. These studies should be helpful in defining the immune mechanism participating in the onset, progression, and resolution of Lyme arthritis.

Hejka, A.; Schmitz, J.L.; England, D.M.; Callister, S.M.; Schell, R.F.

1989-05-01

114

SV40 induces mesotheliomas in hamsters.  

PubMed Central

In the course of studies to elucidate the relative contribution of simian virus 40 (SV40) large T and small t proteins during oncogenesis, we observed the appearance of pericardial and pleural tumors in 100% of Syrian hamsters injected in the pleural space with wild type SV40. When SV40 was injected via the intracardiac or intraperitoneal routes, more than 50% of hamsters developed mesothelial tumors. Macroscopic, microscopic, ultramicroscopic, and histochemical characteristics identify these neoplasms and derived cell lines as mesotheliomas and mesothelioma-derived cell lines. The SV40 genome was integrated and expressed in the mesotheliomas and derived cell lines. The absence of mesotheliomas in hamsters injected with SV40 small t deletion mutants indicates that the small t protein plays an important role in the development of SV40-induced mesotheliomas. To the best of our knowledge, this is the first definitive report of virus-induced mesotheliomas in mammals. Images Figure 1 Figure 2 Figure 3 Figure 4

Cicala, C.; Pompetti, F.; Carbone, M.

1993-01-01

115

Histopathology of Lyme arthritis in LSH hamsters.  

PubMed Central

The authors studied the histopathologic evolution of arthritis in nonirradiated and irradiated hamsters infected with Borrelia burgdorferi. Nonirradiated hamsters injected in the hind paws with B. burgdorferi developed an acute inflammatory reaction involving the synovium, periarticular soft tissues, and dermis. This acute inflammatory reaction was short-lived and was replaced by a mild chronic synovitis as the number of detectable spirochetes in the synovium, periarticular soft tissues, and perineurovascular areas diminished. Exposing hamsters to radiation before inoculation with B. burgdorferi exacerbated and prolonged the acute inflammatory phase. Spirochetes also persisted longer in the periarticular soft tissues. A major histopathologic finding was destructive and erosive bone changes of the hind paws, which resulted in deformation of the joints. These studies should be helpful in defining the immune mechanism participating in the onset, progression, and resolution of Lyme arthritis. Images Figure 2 Figure 3 Figure 7 Figure 8 Figure 1 Figure 4 Figure 5 Figure 6 Figure 9

Hejka, A.; Schmitz, J. L.; England, D. M.; Callister, S. M.; Schell, R. F.

1989-01-01

116

An intercellular pathway for glucose transport into mouse oocytes  

PubMed Central

Glucose is an essential nutrient for mammalian cells. Emerging evidence suggests that glucose within the oocyte regulates meiotic maturation. However, it remains controversial as to whether, and if so how, glucose enters oocytes within cumulus-oocyte complexes (COCs). We used a fluorescent glucose derivative (6-NBDG) to trace glucose transport within live mouse COCs and employed inhibitors of glucose transporters (GLUTs) and gap junction proteins to examine their distinct roles in glucose uptake by cumulus cells and the oocyte. We showed that fluorescent glucose enters both cumulus-enclosed and denuded oocytes. Treating COCs with GLUT inhibitors leads to simultaneous decreases in glucose uptake in cumulus cells and the surrounded oocyte but no effect on denuded oocytes. Pharmacological blockade of of gap junctions between the oocyte and cumulus cells significantly inhibited fluorescent glucose transport to oocytes. Moreover, we find that both in vivo hyperglycemic environment and in vitro high-glucose culture increase free glucose levels in oocytes via gap junctional channels. These findings reveal an intercellular pathway for glucose transport into oocytes: glucose is taken up by cumulus cells via the GLUT system and then transferred into the oocyte through gap junctions. This intercellular pathway may partly mediate the effects of high-glucose condition on oocyte quality.

Wang, Qiang; Chi, Maggie M.; Schedl, Tim

2012-01-01

117

Evidence for mediated protein uptake by amphibian oocyte nuclei  

PubMed Central

The objective of this investigation was to determine whether there is mediated transport of endogenous proteins across the nuclear envelope. For this purpose, we studied the nuclear uptake of a 148,000-dalton Rana oocyte polypeptide (RN1) and compared its actual uptake rate with the rate that would be expected if RN1 crossed the envelope by simple diffusion through the nuclear pores. Nuclear uptake was studied in two ways: first, oocytes were incubated in L-[3H]leucine for 1 h and, at various intervals after labeling, the amount of 3H-RN1 present in the nucleoplasm was determined. Second, L-[3H]leucine-labeled nuclear extracts, containing RN1, were microinjected into the cytoplasm of nonlabeled cells, and the proportion of 3H-RN1 that subsequently entered the nucleus was measured. It was found that RN1 can readily penetrate the nuclear envelope; for example, after 6 h, approximately 36% of the newly synthesized RN1 and 17% of the injected RN1 had entered the nucleus. The diffusion rate through pores having a radius of 45 A was calculated for several possible molecular configurations of RN1. Using axial ratios of 34, 7.5, 2, and 1, the estimated times required to reach 63% of diffusion equilibrium are 757, 468, 6,940 h, and infinity, respectively. Even assuming an axial ratio of 7.5 (the most diffusive configuration) and an equilibrium distribution of 45, simple diffusion through the pores could account for only approximately 1/20 the observed nuclear uptake of RN1. This and other comparisons indicate that some form of mediated transport is involved in the nucleocytoplasmic exchange of this polypeptide.

1983-01-01

118

Ultrastructure of quiescent oocytes of Cebus albifrons.  

PubMed

Quiescent oocytes of the monkey Cebus albifrons were examined with the electron microscope. In many respects the ultrastructure of these cells was similar to that of other mammalian species. Elongate and oval mitochondria, lamellar Golgi complexes, small profiles of smooth endoplasmic reticulum, and vacuolar organelles were randomly distributed around a round nucleus which usually contained a nucleolus and clumps of heterochromatin. Among the unusual morphological characteristics of these oocytes are 'membranous aggregates', membrane-bound organelles containing a complex of convoluted membranes, some very dense rod-like structures and a droplet of moderate density which resembles lipid. A similar droplet is frequently found in mitochondria. Rough endoplasmic reticulum is abundant in many of these oocytes, forming parallel arrays and concentric rings around the nucleus. Folded membrane complexes, apparent elaborations of smooth endoplasmic reticulum, are frequently found in the cytoplasm in continuity with cisternae of smooth and rough endoplasmic reticulum and associated with vesicles which often contain flocculent material. The morphology of Cebus oocytes suggests a greater rate of steroid and protein synthesis, transport, and storage than is usually indicated by the ultrastructure of other mammalian oocytes. PMID:811634

Barton, B R; Hertig, A T

1975-11-01

119

Localization of cortical granule constituents before and after exocytosis in the hamster egg.  

PubMed

Electrical activation of the hamster egg was used to study cortical granule constituents before and after exocytosis. The activated hamster eggs underwent cortical granule decondensation just prior to and at the time of exocytosis. Some of the cortical granules of aged, unactivated eggs underwent similar changes. FITC- and gold-conjugated Lens culinaris agglutinin (LCA) bound intensely to the surfaces of activated but not unactivated eggs. This labelling was associated with the microvilli. Permeabilized eggs exhibited discrete cortical labelling before activation, with a subsequent decrease following the cortical reaction. Gold-conjugated LCA specifically bound to cortical granules when incubated with thin sections. FITC-soybean trypsin inhibitor (SBTI) bound in discrete foci in the cortex of unactivated eggs. Following activation, cortical labelling by SBTI decreased. Aprotinin and benzamidine hydrochloride inhibited FITC-SBTI from binding to the egg cortex. Gold-avidin localization of biotin-SBTI in the electron microscope demonstrated that condensed cortical granules did not bind SBTI but decondensed or exocytosing granules did. This suggests that a cortical granule protease is exposed just prior to exocytosis. Activated eggs exhibited dramatic decreases in the number of hamster sperm penetrating the cytoplasm, suggesting that a plasma membrane block to polyspermy is temporally related to cortical granule exocytosis. PMID:3133448

Cherr, G N; Drobnis, E Z; Katz, D F

1988-04-01

120

CYTOPLASMIC MICROTUBULAR DYNAMIC AND CHROMATIN ORGANIZATION DURING MAMMALIAN OOCYTE MATURATION  

EPA Science Inventory

Coordinated alterations in oocyte chromosome and microtubule disposition occur during oogenesis and oocyte maturation in the mammal. imely transitions in meiotic spindle and cytoplasmic microtubules, due to modifications in both the assembly competence of the tubulin pool and nuc...

121

Laboratory evaluation in oocyte cryopreservation suggests retrieved oocytes are comparable whether frozen for medical indications, deferred reproduction or oocyte donation  

Microsoft Academic Search

Purpose  To compare pre-cryo data from oocyte cryopreservation (OC) cycles performed for malignancy (MED) vs. elective deferment of\\u000a reproduction (DR) or oocyte donation (OD).\\u000a \\u000a \\u000a \\u000a \\u000a Methods  All patients were ?40 y and underwent standard ovarian stimulation and retrieval. Prior to OC, meiotic spindle (MS) and zona\\u000a pellucida (ZP) retardance was measured using digital polarized light microscopy (DPLM).\\u000a \\u000a \\u000a \\u000a \\u000a Results  Of 130 OC cycles, 49 were for

Marie Werner; Andrea Reh; Patty Ann Labella; Nicole Noyes

2010-01-01

122

Penetration of yawed projectiles  

SciTech Connect

We used computer simulations and experiment to study the penetration of tungsten-alloy projectiles into a thick, armored steel target. These projectiles, with length-to-diameter ratios of 4, strike the target with severe yaws, up to 90{degree}(side-on-impact), such as might be induced in an originally longer projectile by a multiple-spaced plate array. In this study, we focus on the terminal ballistics of these projectiles and ignore how the yaw was induced. We found that the minimum penetration depth occurs at 90{degree}yaw. This case is well approximated by the two-dimensional plane-strain penetration of a side-on cylinder. The ratio of penetration depth to diameter, P:D, for this case is larger than that for a sphere because the plane-strain geometry lacks hoop stress, which is activated in axisymmetric geometry. A more surprising result of work is that the penetration at 60{degree} yaw is only slightly deeper than that of the side-on impact. 8 refs., 15 figs., 3 tabs.

Reaugh, J.E.

1990-10-08

123

Cellular and molecular mechanisms of various types of oocyte aging  

Microsoft Academic Search

It is well established that age-related decline of a woman's fertility is related to the poor developmental potential of her\\u000a gametes. The age-associated decline in female fertility is largely attributable to the oocyte aging caused by ovarian aging.\\u000a Age-associated oocyte aging results in a decrease in oocyte quality. In contrast to ovarian aging, there is a concept of postovulatory\\u000a oocyte

Toshifumi Takahashi; Hideki Igarashi; Mitsuyoshi Amita; Shuichiro Hara; Hirohisa Kurachi

124

The human cumulus-oocyte complex gene expression profile  

Microsoft Academic Search

BACKGROUND: The understanding of the mechanisms regulating human oocyte maturation is still rudimentary. We have identified transcripts differentially expressed between immature and mature oocytes and cumulus cells. METHODS: Using oligonucleotide microarrays, genome-wide gene expression was studied in pooled immature and mature oocytes or cumulus cells from patients who underwent IVF. RESULTS: In addition to known genes, such as DAZL, BMP15

Said Assou; Tal Anahory; Véronique Pantesco; Tanguy Le Carrour; Franck Pellestor; Bernard Klein; Lionel Reyftmann; Hervé Dechaud; John De Vos; Samir Hamamah

125

Parthenogenetic development of rabbit oocytes after electrical stimulation  

Microsoft Academic Search

The aim of this study was to determine the effect of electric pulses on the structural and functional condition of rabbit oocytes. The New Zealand White female rabbits at 3-5 months of age and at 3-4 kg body weight served as oocyte donors. Oocytes after flushing from the oviducts were placed between two electrodes in an electroporation chamber which was

A. Wierzchos

126

Induction of yolk formation in hemipteran previtellogenic oocytes (Dysdercus intermedius)  

Microsoft Academic Search

Yolk formation has been studied in previtellogenic oocytes of the telotrophic-meroistic ovariole of the red cotton bug Dysdercus intermedius (Heteroptera: Pyrrhocoridae) in the absence of the follicular epithelium (“skinned oocytes”). Early preparation for endocytosis was seen by urea gel electrophoresis and immunoblotting, which showed that cytosolic clathrin (light chain) is already present in the previtellogenic trophocyte-oocyte syncytium. The ability of

FRANK DITTMANN; MARTINA BICZKOWSKI

1995-01-01

127

Ultrastructural and cytochemical comparison between calf and cow oocytes  

Microsoft Academic Search

The use of prepubertal females (calves) to obtain oocytes for in vitro fertilization (IVF) programs, is being analyzed currently. This will increase the availability of female oocytes and will allow a reduction of the interval between generations. Differentials in the development capability of calf and cow oocytes have been assessed by different authors, establishing several ultrastructural and metabolic differences between

P. de Paz; A. J. Sánchez; J. De la Fuente; C. A. Chamorro; M. Alvarez; E. Anel; L. Anel

2001-01-01

128

Brefeldin A disrupts asymmetric spindle positioning in mouse oocytes  

Microsoft Academic Search

Polar body formation in oocytes is an extreme form of asymmetric cell division, but what regulates the asymmetric spindle positioning and cytokinesis is poorly understood. During mouse oocyte maturation, the metaphase I spindle forms at the center but then moves to the cortex prior to anaphase I and first polar body emission. We show here that treating denuded mouse oocytes

Ling Wang; Zhen-Bo Wang; Xuan Zhang; Greg FitzHarris; Jay M. Baltz; Qing-Yuan Sun; X. Johné Liu

2008-01-01

129

British women's attitudes towards oocyte donation: Ethnic differences and altruism  

Microsoft Academic Search

ObjectiveThis study assessed the importance of altruism and willingness to donate oocytes in British Asian and Caucasian samples. The Theory of Planned Behaviour (TPB) was used to test the importance of attitudes towards oocyte donation, normative and control beliefs to attitudes to donate oocytes.

S. Purewal; O. B. A. van den Akker

2006-01-01

130

Cryopreservation of supernumerary oocytes in IVF\\/ICSI cycles  

Microsoft Academic Search

BACKGROUND: The aim of the present study is to investigate cryopreservation of oocytes in patients refusing embryo cryopreservation for ethical reasons, patients from whom no sperm could be retrieved and patients with enough oocytes to yield a number of fresh and cryopreserved embryos to transfer. METHODS: A total of 2900 oocytes out of 6216 retrieved were cryopreserved in 286 patients

P. E. Levi Setti; E. Albani; P. V. Novara; A. Cesana; G. Morreale

2005-01-01

131

Ultrastructural and cytochemical comparison between calf and cow oocytes.  

PubMed

The use of prepubertal females (calves) to obtain oocytes for in vitro fertilization (IVF) programs, is being analyzed currently. This will increase the availability of female oocytes and will allow a reduction of the interval between generations. Differentials in the development capability of calf and cow oocytes have been assessed by different authors, establishing several ultrastructural and metabolic differences between them. This paper analyzes the morphometric and cytochemical differences between calf and cow oocytes through microscopic techniques. The oocytes morphologically classified as good are processed for electron microscopy a) in Epon 812 epoxy resin for morphometric analysis or b) in low temperature Lowycril K4M resin for cytochemical evaluation using Con A, GS, LPA, UEA, and WGA lectins marked with colloidal gold as probes. Calf oocytes show a greater density of microvilli on their surface and a greater number of endocytosic vesicles than those of the cow. On the other hand, cow oocytes show a larger superior mitochondrial population. In the cumulus cells it can be seen that calf oocytes have a greater volume of lipid droplets. Cytochemical analysis shows that calf oocytes have lectin marking restricted to the plasmic membrane, highlighting the presence of LPA. In cow oocytes, lectin marking can be seen both on the plasmic membrane and in the vacuoles, in both cases, with the LPA highlighted. In the zona pellucida of calf and cow oocytes, the same sugars appear (GS, LPA, WGA), and marking with LPA is more extensive in cow oocytes. PMID:11322238

de Paz, P; Sánchez, A J; De la Fuente, J; Chamorro, C A; Alvarez, M; Anel, E; Anel, L

2001-03-15

132

Egg sharing for assisted conception: a window on oocyte quality  

Microsoft Academic Search

The steep decline in both natural fertility and success after assisted reproduction treatment with increasing maternal age is universally recognized. Large variations in the developmental competence of oocytes collected are seen during assisted cycles, and a link between the biological competence of oocytes retrieved and age has been confirmed. Patients who require donated oocytes can benefit from egg sharing programmes,

Malcolm Faddy; Roger Gosden; Kamal Ahuja; Kay Elder

2011-01-01

133

In vitro Maturation (IVM) of human oocytes.  

PubMed

In vitro maturation is a technique of assisted reproduction which in contrast to standard IVF or ICSI almost fully avoids hormonal stimulation. Immature oocytes will be fully matured in vitro within 24 h after oocyte collection. The method was introduced in the early nineties and is indicated in patients at high risk for ovarian hyperstimulation. Results are almost comparable to standard techniques. Up to now no elevated risk for fetal malformations has been described. IVM is a suitable alternative in IVF for an exactly defined subgroup of patients, in particular patients with PCOS, but still does not replace standard techniques. PMID:24068296

Strowitzki, Thomas

2013-11-01

134

Penetrating eye injuries.  

PubMed Central

A review of all penetrating eye injuries treated at the Manchester Royal Eye Hospital over four years (1 January 1982-31 December 1985) was undertaken. A total of 202 penetrating eye injuries were seen of which 68 (34%) were in children under the age of 15 years. Airgun, dart, and knife injuries accounted for 28 (41%) of the injuries. Thirty seven patients (54%) achieved a good visual result (6/12 or better) and eight (12%) had enucleations. The period of inpatient treatment ranged from two to 18 days. From the analysis of the activities at the time of the injury, many of the injuries can be considered to be preventable.

Patel, B C

1989-01-01

135

A Hamster Model for Streptococcal Impetigo.  

National Technical Information Service (NTIS)

An animal model of impetigo is described in which group A, type 12 beta-hemolytic streptococci were injected intradermally into the back of the Syrian hamster. Seventy-two (96%) of 75 animals so inoculated developed a lesion similar to human impetigo, fro...

A. H. Cushing E. A. Mortimer

1970-01-01

136

IN VITRO CULTURE OF POSTIMPLANTATION HAMSTER EMBRYOS  

EPA Science Inventory

In vitro culture of intact rat and mouse embryos has been described extensively, but information on the culture of other species is sparse. The present study examined some culture requirements of early somite stage hamster embryos and assessed the embryotoxic effects of sodium sa...

137

Preference for bedding material in Syrian hamsters.  

PubMed

This study aimed to determine whether Syrian (golden) hamsters, Mesocricetus auratus, prefer certain bedding materials and whether bedding material can affect paw condition, body weight gain and wheel-running activity. In a first experiment, 26 male hamsters had access to two connected cages, each cage containing a different bedding material (either pine shavings, aspen shavings, corn cob or wood pellets). In a second experiment, 14 male hamsters had access to four connected cages that contained the different bedding materials and also a piece of paper towel to serve as nest material. In a third experiment, 30 male hamsters were each placed in a single cage, 10 of them with pine shavings, 10 with aspen shavings and 10 with corn cob, and they were monitored for 50 days. Significant preferences in the first experiment were: pine shavings over aspen shavings, corn cob over wood pellets, pine shavings over corn cob and aspen shavings over wood pellets (aspen shavings versus corn cob was not tested). However, there was no significant preference expressed in the second experiment, suggesting that the general preference for shavings in the first experiment was based on bedding material suitability as a nesting material. No significant effect of bedding material on paw condition, body weight gain and wheel-running activity was detected. None of the four bedding materials tested in this study can be judged to be inappropriate in the short term if nesting material is added to the cage and if the litter is changed regularly. PMID:17018212

Lanteigne, M; Reebs, S G

2006-10-01

138

Oocyte-granulosa cell interactions during mouse follicular development: regulation of kit ligand expression and its role in oocyte growth  

Microsoft Academic Search

Ovarian folliculogenesis is regulated by both endocrine and intraovarian mechanisms that coordinate the processes of oocyte growth and somatic cell proliferation and differentiation. Within the follicle, paracrine interactions between the oocyte and surrounding granulosa cells are critical for normal cell development and function. This review focuses on the role of paracrine interactions during early oocyte and follicular development that ensure

Fiona H Thomas; Barbara C Vanderhyden

2006-01-01

139

Alterations of spindle and microfilament assembly in aged cat oocytes.  

PubMed

To obtain insights into the cytoplasmic maturation status of cat oocytes recovered from cat ovaries following hormone treatment, we first examined microtubule and microfilament assembly in cat oocytes recovered from hormone-treated ovaries at various stages of maturation. Additionally, we determined the alteration of spindle and microfilament assembly, as well as mitogen-activated protein kinase (MAPK) activity, in cat oocytes at 0, 6, 12 and 18 h of further maturation in vitro. We then looked at pronuclear formation and cleavage of these oocytes following parthenogenetic activation. Similar to other species, microtubules are present in germinal vesicle (GV) stage cat oocytes, and following GV breakdown, microtubules encompassed condensed chromatin particles to form the meiotic metaphase spindle. Microfilaments were located in the cortex and around the GV. A microfilament-rich area, in which the chromatin is located, was observed in the oocytes during meiotic maturation. Maturation rates in aged oocytes (cultured for 18 h) were increased when compared with that in relatively fresh oocytes (<12 h culture), and the number of oocytes with abnormal spindle shapes was also increased in aged oocytes. Furthermore, in aged oocytes, the incidence of the metaphase plate observed outside the thick microfilament domain was higher compared with that of young oocytes, and this seemed to result in an increase in the number of oocytes with two pronuclei and one polar body following activation. Western blot analysis revealed a decrease in MAPK activity in aged cat oocytes. Taken collectively, these results suggest that the optimum time for improved cytoplasmic maturation is <12 h in cat oocytes recovered from hormone-treated ovaries. PMID:21457360

Jin, Y-X; Cui, X-S; Yu, X-F; Han, Y-J; Kong, I-K; Kim, N-H

2010-10-01

140

INFLUENZA VIRUS INFECTION IN THE HAMSTER  

PubMed Central

A study of influenza virus infection in the hamster has yielded the following results: 1. Two influenza A strains (Ga. 47 and PR8) multiplied readily in the hamster lung, although no lung lesions were produced during six serial passages. On further passage both viruses abruptly acquired the capacity to produce pulmonary consolidation and death of the animals. 2. Extracts of the lungs during the early passages contained complement-fixing antigen and infectious virus, as revealed by titration in mice and embryonated eggs. Agglutinins for chicken, human, and guinea pig red cells, however, were not demonstrable at this time. With further passage a close correlation was observed between the capacity of the virus to produce lung lesions in the hamster and to agglutinate mammalian types of red cells. In addition, quantitative changes in the virus population were demonstrated in the lung extracts by complement fixation tests and titrations in mice and eggs. 3. Incubation at 37°C. was effective in bringing out agglutinins in high titer for chicken red cells in lung extracts, which originally failed to agglutinate chicken cells but agglutinated mammalian red cells. This method did not increase the titers of mammalian cell agglutinins. 4. The body temperature of the hamster was found to decrease within 1 to 4 days after inoculation of influenza virus. In the early passages the temperature returned to normal within 24 hours, but with the development of the pathogenic strain of virus the temperature remained at subnormal levels until death. 5. The Lee strain of influenza B virus produced pulmonary lesions in the hamster on the first passage and no increase in pathogenicity of the virus occurred during eleven serial passages. Virus was demonstrable in extracts of the lungs by all the methods used and no difference was observed in its capacity to agglutinate fowl and mammalian types of red cells. The implications of these findings are considered briefly in the discussion.

Friedewald, William F.; Hook, Edward W.

1948-01-01

141

Cannabinoids and hamster circadian activity rhythms.  

PubMed

Circadian activity rhythms in hamsters are entrained to the daily light:dark cycle by photic information arriving from the retina to the suprachiasmatic nucleus, the site of the master circadian pacemaker in mammals. The effects of light on adjusting the timing of the circadian pacemaker is modified, both positively and negatively, by a variety of transmitter systems, but the effects of endocannabinoids have not been reported. Therefore, in this study we evaluated cannabinoids specific for the cannabinoid type 1 receptor (CB(1)) for their ability to modulate light-induced phase advances in hamster circadian activity rhythms. All compounds were administered intraperitoneally. The CB(1) agonist CP55940 potently inhibited light-induced phase shifts with near 90% inhibition achieved with a dose of 0.125 mg/kg. The inhibitory effect of CP55940 was partially reversed by the CB(1) antagonist LY320135 and completely reversed with 1 mg/kg of the CB(1) antagonist AM 251. Neither LY320135 nor AM 251 had any effect on light-induced phase shifts when administered alone. Further evidence for CB(1) involvement in hamster circadian rhythms was provided by immunohistochemical detection of CB(1) receptors in four separate nuclei comprising the principal components of the hamster circadian system: the suprachiasmatic nucleus, intergeniculate leaflet of the thalamus, and dorsal and median raphe nuclei. Altogether these data indicate that the endocannabinoid system has the capability to modulate circadian rhythms in the hamster and cannabis use should be evaluated for adverse effects on circadian rhythms in humans. PMID:18582849

Sanford, Anna E; Castillo, Elizabeth; Gannon, Robert L

2008-05-28

142

Two-microelectrode voltage clamp of Xenopus oocytes: voltage errors and compensation for local current flow.  

PubMed Central

Oocytes from Xenopus laevis are commonly used as an expression system for ion channel proteins. The most common method for their electrophysiological investigation is the two-microelectrode voltage clamp technique. The quality of voltage clamp recordings obtained with this technique is poor when membrane currents are large and when rapid charging of the membrane is desired. Detailed mathematical modeling of the experimental setup shows that the reasons for this weak performance are the electrical properties of the oocytes and the geometry of the setup. We measured the cytosolic conductivity to be approximately 5 times lower than that of the typical bath solution, and the specific membrane capacitance to be approximately 6 times higher than that of a simple lipid bilayer. The diameter of oocytes is typically approximately 1 mm, whereas the penetration depth of the microelectrodes is limited to approximately 100 microm. This eccentric current injection, in combination with the large time constants caused by the low conductivity and the high capacitance, yields large deviations from isopotentiality that decay slowly with time constants of up to 150 micros. The inhomogeneity of the membrane potential can be greatly reduced by introducing an additional, extracellular current-passing electrode. The geometrical and electrical parameters of the setup are optimized and initial experiments show that this method should allow for faster and more uniform control of membrane potential.

Baumgartner, W; Islas, L; Sigworth, F J

1999-01-01

143

Oocyte growth in the sheepshead minnow: uptake of exogenous proteins by vitellogenic oocytes.  

PubMed

The structure of the vitellogenic follicles of the sheepshead minnow, Cyprinodon variegatus, is described. Follicles enlarge primarily by protein yolk accumulation (vitellogenesis) and subsequently increase in size by hydration. This study uses the electron-dense tracer, horseradish peroxidase, and a larger heterologous protein, Xenopus laevis [3H]vitellogenin, to follow the fate of exogenous proteins from the maternal circulation to yolk spheres of the growing oocyte. Materials appear to leave the perifollicular capillaries via an interendothelial route, traverse the theca and the patent intercellular channels of the follicular epithelium and the pore canals of the vitelline envelope. At the oocyte surface they are incorporated via micropinocytosis and translocated to growing yolk spheres in the peripheral ooplasm. In contrast to other studies on oocyte growth in teleosts which suggest that yolk is an autosynthetic product, this study substantiates the importance of heterosynthetic processes during oocyte growth in C. variegatus. PMID:7147228

Selman, K; Wallace, R A

1982-01-01

144

Penetration resistant barrier  

DOEpatents

The disclosure relates to a barrier for resisting penetration by such as hand tools and oxy-acetylene cutting torches. The barrier comprises a layer of firebrick, which is preferably epoxy impregnated sandwiched between inner and outer layers of steel. Between the firebrick and steel are layers of resilient rubber-like filler.

Hoover, William R. (Albuquerque, NM); Mead, Keith E. (Albuquerque, NM); Street, Henry K. (Albuquerque, NM)

1977-01-01

145

Jet penetration in glass  

SciTech Connect

We describe a phenomenological model which accounts for the mechanical response of glass to intense impulsive loading. An important aspect of this response is the dilatancy accompanying fracture. We have also conducted a number of experiments with 38.1-mm diameter precision shaped charges to establish the performance against various targets and to allow evaluation of our model. At 3 charge diameters standoff, the data indicate that both virgin and damaged glass offer better (Bernoulli-scaled) resistance to penetration than either of 4340 steel, or 6061-T6 aluminum alloy. Time-resolved measurements indicate two distinct phases of jet penetration in glass: An initial hydrodynamic phase, and a second phase characterized by a slower penetration velocity. Our calculations show that at early time, a crater is formed around the jet and only the tip of the undisturbed jet interacts with the glass. At late time the glass has collapsed on the jet and degraded penetration continues via a disturbed and fragmented jet.

Moran, B.; Glenn, L.A.; Kusubov, A.

1991-05-01

146

A penetration mechanics database  

NASA Astrophysics Data System (ADS)

A penetration mechanics database has been compiled that contains experimental results from a variety of researchers of different nationalities (German, French, English, Canadian, and American), during different decades (the 1960's to the 1990's), and with different purposes or objectives (space debris impact, armor design and evaluation, penetrator design and evaluation, and theoretical verification). The data fall naturally into three subgroupings: (1) penetration into semi-infinite targets; (2) perforation of finite-thickness targets; and (3) penetration from multiple impact (segmented rods). Data collection was primarily limited to experiments conducted against generic type targets, and emphasis was placed on data that would be more relevant to heavy armor issues. This diverse collection of data for metallic targets has been tabulated; data tables include the initial impact conditions, the projectile and target geometries and materials, and the measured response. Information on the materials, e.g., hardness of yield strength, along with impact information such as yaw has been tabulated if available. Graphical displays of the data have been used to summarize the data, and cross-plotting that combines data from different sources has also been provided.

Anderson, Charles E., Jr.; Morris, Bruce L.; Littlefield, David L.

1992-01-01

147

Chainsaw penetrating neck injury.  

PubMed

A case of chainsaw injury to the neck is described. Previous reports in the English language are exceedingly rare. A brief discussion of safety features on chain saws is followed by a review of selective vs. mandatory surgical exploration in penetrating neck trauma, including the role of ancillary diagnostic tests. PMID:7582411

Brown, A F

1995-06-01

148

Chainsaw penetrating neck injury  

Microsoft Academic Search

A case of chainsaw injury to the neck is described. Previous reports in the English language are exceedingly rare. A brief discussion of safety features on chain saws is followed by a review of selective vs. mandatory surgical exploration in penetrating neck trauma, including the role of ancillary diagnostic tests.

A F Brown

1995-01-01

149

Sperm and Oocyte Communication Mechanisms Controlling C. elegans Fertility  

PubMed Central

During sexual reproduction in many species, sperm and oocyte secrete diffusible signaling molecules to help orchestrate the biological symphony of fertilization. In the Caenorhabditis elegans gonad, bidirectional signaling between sperm and oocyte is important for guiding sperm to the fertilization site and inducing oocyte maturation. The molecular mechanisms that regulate sperm guidance and oocyte maturation are being delineated. Unexpectedly, these mechanisms are providing insight into human diseases, such as amyotrophic lateral sclerosis, spinal muscular atrophy, and cancer. Here we review sperm and oocyte communication in C. elegans and discuss relationships to human disorders.

Han, Sung Min; Cottee, Pauline A.; Miller, Michael A.

2010-01-01

150

Awakening the oocyte: controlling primordial follicle development  

Microsoft Academic Search

Oocytes are sequestered in primordial follicles before birth and remain quiescent in the ovary, often for decades, until recruited into the growing pool throughout the reproductive years. Therefore, activation of follicle growth is a major biological checkpoint that controls female reproductive potential. However, we are only just beginning to elucidate the cellular mechanisms required for either maintenance of the quiescent

Eileen A McLaughlin; Skye C McIver

2008-01-01

151

Ovulation Triggers Activation of Drosophila Oocytes  

Microsoft Academic Search

Drosophila melanogaster mature oocytes in ovaries are arrested at metaphase I of meiosis. Eggs that have reached the uterus have released this arrest. It was not known where in the female reproductive tract egg activation occurs and what triggers it. We investigated when and where the egg is activated in Drosophila in vivo and at what meiotic stage the egg

Yael Heifetz; Jing Yu; Mariana F. Wolfner

2001-01-01

152

Sensitivity of canine oocytes to low temperature.  

PubMed

This study compared the viability of canine oocytes after storage for 5 h at 4 or 38 degrees C. The ovaries were collected after ovariohysterectomy of bitches and transported to the laboratory within 5 h at 4 or 38 degrees C. The collected oocytes were matured in DMEM supplemented with 10% FBS, 0.6 mM/mL cysteine, 0.2 mM pyruvic acid, 20 ng/mL E2 and 1 microg/mL rbST, and incubated for 0, 24 and 48 h, at 38 degrees C and in 95% air with 5% CO2. The viability of the oocytes after 0 h did not differ significantly between 4 and 38 degrees C group (79.6% versus 83.9%), but after 24 and 48 h, significant differences were apparent (13.2% versus 77.8% after 24 h and 0.0% versus 72.9% after 48 h; P < 0.05). Therefore, canine oocytes were remarkably sensitive to low temperatures. PMID:16499959

Lee, H S; Yin, X J; Kong, I K

2006-02-23

153

Visualizing RNA Localization in Xenopus Oocytes  

PubMed Central

RNA localization is a conserved mechanism of establishing cell polarity. Vg1 mRNA localizes to the vegetal pole of Xenopus laevis oocytes and acts to spatially restrict gene expression of Vg1 protein. Tight control of Vg1 distribution in this manner is required for proper germ layer specification in the developing embryo. RNA sequence elements in the 3' UTR of the mRNA, the Vg1 localization element (VLE) are required and sufficient to direct transport. To study the recognition and transport of Vg1 mRNA in vivo, we have developed an imaging technique that allows extensive analysis of trans-factor directed transport mechanisms via a simple visual readout. To visualize RNA localization, we synthesize fluorescently labeled VLE RNA and microinject this transcript into individual oocytes. After oocyte culture to allow transport of the injected RNA, oocytes are fixed and dehydrated prior to imaging by confocal microscopy. Visualization of mRNA localization patterns provides a readout for monitoring the complete pathway of RNA transport and for identifying roles in directing RNA transport for cis-acting elements within the transcript and trans-acting factors that bind to the VLE (Lewis et al., 2008, Messitt et al., 2008). We have extended this technique through co-localization with additional RNAs and proteins (Gagnon and Mowry, 2009, Messitt et al., 2008), and in combination with disruption of motor proteins and the cytoskeleton (Messitt et al., 2008) to probe mechanisms underlying mRNA localization.

Gagnon, James A.; Mowry, Kimberly L.

2010-01-01

154

Mouse oocyte killing by neutrons: target considerations  

SciTech Connect

Highly radiosensitive primordial mouse oocytes, the principal cells at genetic risk in the female, have been studied using 0.43-MeV neutrons. Analysis of the survival curve (D/sub 37/ = 0.055 Gy) indicates that the diameter of the radiosensitive target (assumed spherical and of unit density) is larger than that of the nucleus but not of the oocyte, implicating a non-nuclear but sub-cellular target. This is consistent with results from /sup 3/H-thymidine incorporated in DNA. Our efforts to identify the extraordinarily radiosensitive lethality target in these primordial oocytes suggest it is the plasma membrane. Monte Carlo calculations for 0.43-MeV neutrons show that at the D/sub 37/ only a single proton recoil will traverse the plasma membrane, consistent with the observed exponential survival curve. A highly sensitive non-DNA target for mouse oocyte killing may importantly influence interpretations of genetic mutation data from mice and their use in estimating genetic risk in humans. 7 refs., 1 fig., 1 tab.

Straume, T.; Dobson, R.L.

1985-04-01

155

Bioactivation of diethylstilbestrol by the Syrian hamster kidney  

SciTech Connect

Male Syrian golden hamsters chronically exposed to diethylstilbestrol (DES) develop renal adenocarcinomas with an incidence approaching 100%. The ability of the hamster kidney to bioactivate DES was assessed using hamster kidney slices. The male hamster renal cortex has a 2- to 5-fold greater capacity to irreversibly bind ({sup 3}H)DES as compared with female hamster renal cortex and with male hamster renal medulla. Incubation of the tissue under anaerobic conditions inhibited the metabolism and irreversible binding of ({sup 3}H)DES. Gel electrophoresis analysis of covalently modified proteins revealed several radioactive peaks indicating that specific adduct formation had occurred. The cytochrome P-450 inhibitors SKF 525-A, metyrapone, carbon monoxide, butylated hydroxytoluene, and dicumarol decreased the irreversible binding of ({sup 3}H)DES to renal cortical protein by 38 to 72%.

Adams, S.P.

1987-01-01

156

Campylobacter cinaedi is normal intestinal flora in hamsters.  

PubMed Central

During the course of studies to reproduce proliferative enteritis in hamsters, Campylobacter cinaedi was recovered from the feces of the majority of healthy hamsters obtained from two commercial sources. The organisms were cultured by using filtration, a nonselective medium, and a microaerophilic atmosphere containing hydrogen. Isolation was hindered by the fastidious nature of C. cinaedi and by the presence of other Campylobacter species in the hamster intestine. All hamster C. cinaedi isolates were phenotypically similar to C. cinaedi ATCC 35683. Comparison of whole-cell protein profiles of one hamster isolate with a reference strain of C. cinaedi by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with C. cinaedi-specific rabbit antiserum supported the phenotypic identification of these isolates. Hamsters may be an animal reservoir for human C. cinaedi infections. Images

Gebhart, C J; Fennell, C L; Murtaugh, M P; Stamm, W E

1989-01-01

157

Cell penetration by transportan  

Microsoft Academic Search

ABSTRACT Transportan is a 27 amino,acid-long peptide containing 12 functional amino acids from the amino terminus of the neuropeptide galanin and mastoparan in the carboxyl terminus, connected via a lysine. Transportan is a cell-penetrating peptide as judged by indirect immunofluorescence using N,I-labeled peptide. At 377C, the maximal intracellular concentration is reached in about 20 min. The internalized transpor- tan is

Margus Pooga; Mattias Ha Llbrink; Matjal Zorko; U Lo Langel

158

Antibody tumor penetration  

PubMed Central

Antibodies have proven to be effective agents in cancer imaging and therapy. One of the major challenges still facing the field is the heterogeneous distribution of these agents in tumors when administered systemically. Large regions of untargeted cells can therefore escape therapy and potentially select for more resistant cells. We present here a summary of theoretical and experimental approaches to analyze and improve antibody penetration in tumor tissue.

Thurber, Greg M.; Schmidt, Michael M.; Wittrup, K. Dane

2009-01-01

159

Age-associated alteration of oocyte-specific gene expression in polar bodies potential markers of oocyte competence  

PubMed Central

Objective To confirm that oocyte-specific mRNAs are detectable in the polar body (PB) of MII oocytes and determine the effect of age on oocyte-specific transcript levels. Design Prospective study Setting Hospital-based academic research laboratory Animals CD1 female mice Intervention(s) Aged (40–50 weeks) and young (7–9 weeks) mice were administered pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotrophin (hCG). Oocytes were fertilized in vitro to assess fertilization and developmental competence. MII oocytes were obtained and first PBs was removed. mRNA from each PB and its sibling oocyte was reverse transcribed and analyzed by real-time quantitative PCR. Main Outcome Measure(s) Fertilization and developmental rates and expression of 6 oocyte-specific genes (Bmp15, Gdf9, H1foo, Nlrp5, Tcl1, and Zp3) in PBs and sibling oocytes from young vs. aged mice. Result(s) Oocytes from aged mice had lower developmental competence. Four genes (H1foo, Nlrp5, Tcl1, and Zp3) were differentially expressed in aged vs. young oocytes (P < 0.05). All 6 transcripts were present in PBs from aged and young mice at lower levels than in the sibling oocytes; transcript levels were lower in aged PBs compared with young PBs (P < 0.05). Conclusion(s) There is a significant difference in the transcript levels of oocyte-specific genes in aged vs. young PB that correlates with age-related decreases in oocyte competence. Differences in gene expression in PB may be potential biomarkers of MII oocyte competence.

Jiao, Ze-Xu; Xu, Min; Woodruff, Teresa K

2012-01-01

160

9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.  

Code of Federal Regulations, 2010 CFR

...enclosures used to transport live guinea pigs and hamsters. 3.36 Section 3.36...Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards...enclosures used to transport live guinea pigs and hamsters. No person subject...

2010-01-01

161

9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.  

Code of Federal Regulations, 2010 CFR

...enclosures used to transport live guinea pigs and hamsters. 3.36 Section 3.36...Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards...enclosures used to transport live guinea pigs and hamsters. No person subject...

2009-01-01

162

A potassium current evoked by growth hormone-releasing hormone in follicular oocytes of Xenopus laevis.  

PubMed Central

1. Electrophysiological properties of the growth hormone-releasing hormone (GRH) receptor were studied in Xenopus oocytes with an intact follicle cell layer (i.e. follicular oocytes) by measuring whole-cell current using the two-electrode voltage-clamp method. 2. A slow transient outward current was elicited in oocytes, clamped at -60 mV, by the application of rat GRH but not bovine, porcine, or human GRH. 3. The response to GRH was not suppressed by blockers known to inhibit other endogenous receptors present in follicular Xenopus oocytes; blockers used were timolol (2 microM; beta-adrenergic blocker), theophylline (0.1 mM; purinergic blocker) and atropine (100 nM; muscarinic blocker). 4. The current response evoked by rat GRH occurred in a dose-dependent manner. The concentrations of GRH for threshold and maximum responses were 1 and 100 nM respectively and the estimated EC50 (half-maximal effective concentration) was approximately 7 nM. The amplitude and conductance of the response became larger and the latency, time-to-peak and half-decay time were shortened when the concentration of GRH was increased. 5. The GRH response was reversibly inhibited by a K+ channel blocker, tetraethylammonium+ (TEA+; 20 mM). The reversal potential for the GRH response was around -100 mV and was compatible with the reported value for a K+ current in Xenopus oocytes. Furthermore, a depolarizing shift of 40 mV in the reversal potential was observed when the external K+ concentration was increased from 2 to 10 mM, agreeing with the Nernst equation. In contrast, no significant shift in the reversal potential was observed by changing the external concentration of Na+ or Cl-. 6. The GRH response was not suppressed in oocytes treated with an acetoxy-methyl ester of bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA/AM; 10 microM) which penetrates the cell membrane and chelates internal Ca2+. 7. The GRH response was potentiated by pre-treatment with forskolin (0.4 microM; 5 min), which stimulates adenylate cyclase and increases the internal concentration of adenosine 3',5'-cyclic monophosphate (cyclic AMP). 8. The GRH response was not obtainable when follicle cells surrounding oocytes were removed mechanically with forceps or enzymically with collagenase (i.e. denuded oocytes). The response was also suppressed when gap junctions, which electrically couple follicle cells and the oocyte, were blocked by 1-octanol (1 mM). 9. The first amino acid is considered to be important for the binding of peptide ligands to their receptors.(ABSTRACT TRUNCATED AT 400 WORDS)

Yoshida, S; Plant, S

1991-01-01

163

Prediction of alumina penetration  

SciTech Connect

The MESA hydrocode was used to predict two-dimensional tests of L/D 10 and L/D 15 tungsten rods impacting AD 90 alumina with a steel backing. The residual penetration into the steel is the measured quantity in these experiments conducted at the Southwest Research Institute (SWR). The interface velocity as a function of time between an alumina target and a lithium fluoride window, impacted by an alumina disk at velocities between 544 m/s and 2329 m/s, was also predicted. These one-dimensional flyer plate experiments were conducted at Sandia National Laboratories using Coors AD 995 alumina. The material strength and fracture models are important in the prediction of ceramic experiments. The models used in these predictions are discussed. The penetrations in the two-dimensional tests were predicted to 11.4 percent or better. In five of the six experiments, the predicted penetration depth was deeper than the measured value. This trend is expected since the calculation is based on ideal conditions. The results show that good agreement between the 1-D flyer plate data and the MESA predictions exists at the lower impact velocities, but the maximum velocity is overpredicted as the flyer plate velocity increases. At a flyer plate velocity of 2329 m/s the code overpredicted the data by 12.3 percent.

Mandell, D.A.

1993-02-01

164

Uracil metabolism in golden hamster after irradiation.  

PubMed

The catabolism of uracil and the total balance of excreted radioactivity were studied in golden hamsters after a peroral application of 14C-uracil. Twenty-four hours after administration most of the radioactivity taken up appeared in expired carbon dioxide. The percent proportion of radioactivity in carbon dioxide was independent of the amount of uracil administered. On the other hand, the percentage of radioactivity excreted in urine depended on the amount of uracil taken up, high doses of the compound causing up to eight-fold increase in urine-excreted radioactivity. Most of the exogenously-administered uracil was catabolized within the first 5 hours. Irradiation had no substantial effect on the dynamics of uracil catabolism. Analysis of urine revealed that most urine-excreted radioactivity is in the form of uracil. On peroral application of high doses of uracil to irradiated hamsters, their urine was found to contain barbituric acid which originated from uracil. PMID:300720

Buric, L; Grinberg, A; Muizniek, I; Novák, F; Vitol, M; Dienstbier, Z

1977-02-01

165

Percutaneous Penetration Enhancers: An Overview  

Microsoft Academic Search

Transdermal drug delivery is the controlled release of drugs through the skin to obtain therapeutic levels systematically. Several technological advances have been made in the recent decades to enhance percutaneous drug penetration. This overview focuses on the physical, biochemical, and chemical means of penetration enhancement, as well as the classification and mechanisms of chemical penetration enhancers, their application in transdermal

H.-Y. Thong; H. Zhai; H. I. Maibach

2007-01-01

166

Asbestos cement dust inhalation by hamsters  

Microsoft Academic Search

Two groups of 96 male Syrian golden hamsters were exposed to respirable asbestos cement aerosol at concentrations of approximately 1 and approximately 10 micrograms\\/liter, respectively, 3 hours\\/day, 5 days\\/week. Average fiber counts ranged from 5 to about 120 fibers\\/cm3. Each group was randomly divided into six subgroups of 16 animals. The first subgroup was sacrificed after 3 months of exposure,

A. P. Wehner; G. E. Dagle; W. C. Cannon; R. L. Buschbom

1978-01-01

167

Taste Qualities of Solutions Preferred by Hamsters  

Microsoft Academic Search

Molecules of diverse chemical structure are sweet to humans and several lines of evidence (genetic, physiological, behavioral) suggest that there may be distinct sweet perceptual qualities. To address how many perceptual categories these molecules elicit in hamsters (Mesocricetus auratus), we studied patterns of generalization of conditioned taste aversions for seven sweeteners: 100 mM sucrose, 320 mM maltose, 32 mM D-phenylalanine,

Bruce I. MacKinnon; Marion E. Frank; Thomas P. Hettinger; Bradley G. Rehnberg

1999-01-01

168

Lactational exposure to methylmercury in the hamster  

Microsoft Academic Search

Syrian Golden hamster dams were administered 203Hg-labelled methyl mercury (MeHg; 1.6 ?mol\\/kg) 1 day after parturition and milk was collected twice during the 1st week. The\\u000a excretion of 203Hg in milk and the uptake, retention and tissue distribution of 203Hg in the pups was studied using gamma counting. The fraction of inorganic Hg in milk and in the kidneys of

Kerstin Norderthgll; Lennart Dock; Marie Vahter

1995-01-01

169

Sex aneuploidy of unfertilized human oocytes after intracytoplasmic sperm injection  

SciTech Connect

Intracytoplasmic sperm injection (ICSI) has recently achieved successful fertilization and pregnancy in human in vitro fertilization, particularly in cases of severe male factor infertility. One criticism of this novel clinical technique is that it bypasses the natural selection process of fertilization. We use fluorescence in situ hybridization (FISH) to analyze oocytes which fail to fertilize after ICSI in the Yale IVF Program. The purpose of this study is to determine whether failed fertilization after ICSI can be attributed to sex chromosome aneuploidy in the oocyte. Fertilization of oocytes is determined by the presence of two pronuclei on light microscopic examination (400X). Multi-probe FISH with DAPI (4,6,-diamino-2-phenyl-indole) counterstain is then performed to determine oocyte ploidy and the presence of decondensed sperm. Centromeric probes for X, Y and 17 are used simultaneously in each oocyte for in situ hybridization to oocyte chromatin. In all oocytes examined after ICSI to date, unfertilized oocytes have decondensed sperm DNA present confirming appropriate intracytoplasmic placement of the sperm. Preliminary results obtained from 31 oocytes have not identified any sex chromosome aneuploidies. The FISH technique used in post-ICSI oocytes is a model system for delineating genetic causes of failed fertilization in the human.

Lee, G.; Ward, D.C.; Jones, E.E. [Yale Univ., New Haven, CT (United States)

1994-09-01

170

Protein uptake in the oocytes of the cecropia moth.  

PubMed

The formation of yolk spheres in the oocyte of the cecropia moth, Hyalophora cecropia (L.), is known immunologically to result largely from uptake of a sex-limited blood protein. Recent electron microscope analyses of insect and other animal oocytes have demonstrated fine structural configurations consistent with uptake of proteins by pinocytosis. An electron microscope analysis of the cecropia ovary confirms the presence of similar structural modifications. With the exception of two apparently amorphous layers, the basement lamella on the outer surface of the follicular epithelium and the vitelline membrane on the inner, there is free access of blood to the oocyte surface between follicle cells. Dense material is found in the interfollicular cell space and adsorbed to the outer surface of the much folded oocyte membrane. Pits in the oocyte membrane and vesicles immediately under it are lined with the same dense material not unlike the yolk spheres in appearance. Introduction of ferritin into the blood of a developing cecropia moth and its localization adsorbed to the surface of the oocyte, and within the vesicles and yolk spheres of the oocyte cortex, is experimental evidence that the structural modifications of the oocyte cortex represent stages in the pinocytosis of blood proteins which arrive at the oocyte surface largely by an intercellular route. Small tubules attached to the yolk spheres are provisionally interpreted as a manifestation of oocyte-synthesized protein being contributed to the yolk spheres. PMID:5892960

Stay, B

1965-07-01

171

The mammalian oocyte orchestrates the rate of ovarian follicular development  

PubMed Central

The development of both the mammalian oocyte and the somatic cell compartments of the ovarian follicle is highly coordinated; this coordination ensures that the ovulated oocyte is ready to undergo fertilization and subsequent embryogenesis. Disruption of this synchrony results in oocyte developmental failure. Communication between the oocyte and companion somatic cells is essential for successful development of both follicular compartments. However, it was not previously known whether one cell type, either the somatic or the germ cell compartment, determines the overall rate of follicular development. To test the hypothesis that the oocyte orchestrates the rate of follicle development, mid-sized oocytes isolated from secondary follicles were transferred back to primordial follicles, the earliest stage of follicular development. This transfer doubled the rate of follicular development and the differentiation of follicular somatic cells. Oocyte development in these accelerated follicles appeared normal; recovered oocytes were competent to undergo fertilization and embryonic development. These results demonstrate that oocytes orchestrate and coordinate the development of mammalian ovarian follicles and that the rate of follicular development is based on a developmental program intrinsic to the oocyte.

Eppig, John J.; Wigglesworth, Karen; Pendola, Frank L.

2002-01-01

172

Molecular Characterization of a Hamster Viscerotropic Strain of Yellow Fever Virus  

Microsoft Academic Search

A hamster viscerotropic strain of yellow fever (YF) virus has been derived after serial passage of strain Asibi through hamsters. The parental Asibi\\/hamster p0 virus causes a mild and transient viremia in hamsters with no outward, clinical signs of illness. In contrast, the viscerotropic Asibi\\/hamster p7 virus causes a robust viremia, severe illness, and death in subadult hamsters. The genome

Monica A. McArthur; Miguel T. Suderman; John-Paul Mutebi; Shu-Yuan Xiao; Alan D. T. Barrett

2003-01-01

173

Subacute sclerosing panencephalitis (SSPE) agent in hamsters.  

PubMed

A hamster-adapted SSPE agent was shown to cause a productive infection in weanling hamster brain, which changed to a cell-associated or defective infection coincident with the appearance of measles antibodies in serum. Antibodies to measles hemagglutinin, hemolysin and neucleocapsid antigens developed in serum, which also contained neutralizing activity for regular measles virus. The agent recovered from the brains prior to the appearance of serum antibodies was infectious in cell-free media, capable of rapidly destroying Vero-cell cultures and able to progressively destroy primary hamster brain cultures. In contrast the agent recovered from the brain after serum antibodies were present, was infectious only within cells destroyed Vero-cells ineffectively and spread slowly through primary brain tissue cultures releasing minute amounts of extracellular virus intermittently. Nevertheless, infected giant cells in the primary brain cultures contained both the HA & HL measles antigens in their cytoplasmic membranes. This in vivo conversion of a productive to a cell-associated cerebral infection appeared to be caused by the host antibody response and may mirror the initial events of human SSPE and possibly other slow or latent measles infections of the CNS. PMID:99679

Johnson, K P; Norrby, E

1977-01-01

174

The immune response in the hamster  

PubMed Central

Synthesis of antibody to hen egg albumin (HEA) was restricted to one of the 7S immunoglobulins (7S?1-globulin) when hamsters were inoculated with soluble HEA (HEA—saline). This selective induction occurred regardless of the amount of HEA—saline injected (0.001–5.0 mg) or the route of inoculation. In contrast, HEA in Freund's adjuvants induced synthesis of anti-HEA in both the 7S?1- and 7S?2-globulins, even when as little as 0.1 ?g of HEA was used. Repeated inoculations of hamsters with HEA—saline increased or maintained 7S?1-antibody, but did not induce anti-HEA synthesis in the 7S?2-globulins. The results of cell transfer experiments indicated that cells from HEA—saline treated hamsters were primed to synthesize 7S?1 anti-HEA and were specifically unresponsive for 7S?2 anti-HEA synthesis. Selective induction of antibody production and unresponsiveness, concomitantly, within different immunoglobulin classes suggests that different antibody induction mechanisms are utilized by these two immunoglobulin classes. ImagesFIG. 3FIG. 4FIG. 6FIG. 7FIG. 8FIG. 9

Coe, J. E.

1971-01-01

175

Oxytocin inhibits aggression in female Syrian hamsters.  

PubMed

Dominant subordinate relationships are formed as the result of social conflict and are maintained at least in part by communication. At this time, little is known about the neural mechanisms that are responsible for coordinating the social behaviours (e.g. aggression) that occur in association with the formation and maintenance of these relationships. The purpose of the present study was to investigate the role of oxytocin (OXT) within the medial preoptic anterior hypothalamic continuum (MPOA-AH) in the control of aggression in female hamsters. OXT injected into the MPOA-AH immediately before testing significantly reduced the duration of aggression in a dose-dependent manner. Injection of an OXT antagonist 30 min before testing significantly increased the duration of aggression. In contrast, the duration of aggression was not altered when hamsters were tested either 30 min after injection of OXT or immediately following injection of an OXT-antagonist. These data support the hypothesis that OXT release within the MPOA-AH regulates social behaviours important in the formation and maintenance of dominant subordinate relationships in female hamsters. PMID:12472877

Harmon, A C; Huhman, K L; Moore, T O; Albers, H E

2002-12-01

176

Comparison of preimplantation developmental competence after mouse oocyte growth and development in vitro and in vivo  

Microsoft Academic Search

Culture systems for oocytes are essential for the experimental analysis of the basic mechanisms of oocyte development and, moreover, they will eventually find wide application in agriculture, the clinic, and wildlife preservation. Here, progress in mouse oocyte growth and development in vitro using oocyte-granulosa cell complexes from preantral follicles is reviewed. Oocyte-granulosa cell complexes were isolated from preantral (secondary) follicles

J. J. Eppig; M. J. O'Brien

1998-01-01

177

Selection of developmentally competent buffalo oocytes by brilliant cresyl blue staining before IVM  

Microsoft Academic Search

The brilliant cresyl blue (BCB) test determines the activity of glucose-6-phosphate dehydrogenase (G6PDH); the activity of this enzyme is greatest in growing oocytes, but it declines as oocytes mature. The objective was to develop and evaluate this test for assessing development of buffalo oocytes (to select developmentally competent oocytes for increased in vitro embryo production). Oocytes were exposed to BCB

B. M. Manjunatha; P. S. P. Gupta; M. Devaraj; J. P. Ravindra; S. Nandi

2007-01-01

178

Tumor-related gene changes in immunosuppressive Syrian hamster cholangiocarcinoma.  

PubMed

The results of a previous study demonstrated that prednisolone enhanced cholangiocarcinogenesis. Therefore, to clarify molecular changes during immunosuppressive cholangiocarcinogenesis, Syrian hamsters were divided into 8 groups: uninfected controls; immunosuppressed Syrian hamsters using prednisolone (P); normal Syrian hamsters administered N-nitrosodimethylamine (ND); immunosuppressed Syrian hamsters administered N-nitrosodimethylamine (NDis); normal Syrian hamsters infected with Opisthorchis viverrini (OV); immunosuppressed Syrian hamsters infected with O. viverrini (OVis); normal Syrian hamsters infected with O. viverrini and administered N-nitrosodimethylamine (CCA); and immunosuppressed Syrian hamsters infected with O. viverrini and administered N-nitrosodimethylamine (CCAis). Syrian hamster livers were used for analysis of tumor-related gene expression and immunohistochemistry through cytokeratin 19 (CK19) and proliferating cell nuclear antigen (PCNA) staining. The tumor-related gene expression results show that CCAis groups at all time points exhibited upregulation of COX-2, IL-6, SOD1, CAT and iNOS and downregulation of p53, which correlated with the predominant expression of CK19 and PCNA in liver tissue. These results suggest that prednisolone enhances cholangiocarcinoma development, which was confirmed by molecular changes. PMID:23645518

Juasook, Amornrat; Aukkanimart, Ratchadawan; Boonmars, Thidarut; Sudsarn, Pakkayanee; Wonkchalee, Nadchanan; Laummaunwai, Porntip; Sriraj, Pranee

2013-05-06

179

An unusual response of hamster lymphocytes to PHA  

PubMed Central

Lymphocytes from lymph nodes, spleen or thymus of hamsters differ from those of guinea-pig, rat or mouse in their response to PHA by reacting maximally at concentrations 10–50 times higher than those optimal for other rodents. The cells from the other animals were inhibited by the levels optimal for hamster cells. Hamster lymphocytes, however, resembled cells of the other rodents in their dose response to Con A or PWM. The possibility that the particularity in response of hamster cells is related to number and/or distribution of PHA-receptors is discussed.

Ron, Noemi; Laufer, A.; Gery, I.

1973-01-01

180

Cardiac carnitine deficiency and altered carnitine transport in cardiomyopathic hamsters.  

PubMed

The Bio 14.6 hamster has a well-documented cardiomyopathy which leads to congestive heart failure. Previous work demonstrated that hearts from these hamsters have depressed fatty acid oxidation and depressed carnitine concentrations compared to those of normal hamsters. Analyses of tissue carnitine concentrations from 40 to 464 days of age demonstrate that the cardiomyopathic hamsters have a cardiac carnitine deficiency throughout life. Therefore, the carnitine deficiency is not a secondary effect of an advanced stage of the cardiomyopathy. Both the observation that other tissues of the cardiomyopathic hamster have normal or markedly elevated carnitine concentrations and the observation that oral carnitine treatment could not increase the cardiac carnitine concentrations to those of normal hamsters are consistent with the hypothesis that the cardiac carnitine deficiency is the result of a defective cardiac transport mechanism. Cardiac carnitine-binding protein (which may function in the cardiac carnitine transport mechanism) prepared from hearts of cardiomyopathic hamsters had a lower maximal carnitine binding and an increased dissociation constant for carnitine compared to the cardiac carnitine-binding protein prepared from normal hamsters. Thus, several types of data indicate that the cardiomyopathic hamster has an altered cardiac carnitine transport mechanism. PMID:6838206

York, C M; Cantrell, C R; Borum, P R

1983-03-01

181

Oocyte peptides as paracrine tools for ovarian stimulation and oocyte maturation.  

PubMed

Recent studies report the production and isolation of a stable bioactive recombinant human bone morphogenetic protein 15 (rhBMP15) that is appropriately processed in HEK-293 cells and activates the SMAD 1/5/8 pathway in mouse granulosa cell cultures. Further, the purified rhBMP15 induces the expression of genes associated with cumulus expansion. Thanks to recent research, we have a greater understanding of the importance of the dialogue that occurs between the oocyte and the granulosa cell layer with regard to regulating folliculogenesis and the acquisition of oocyte developmental competence and maturation. BMP15 is one of the critical components of these intra-follicular communication pathways. The production of recombinant human BMP15 is important for understanding the biochemistry of this specific pathway and for also fully understanding its functional contributions to mediating oocyte development. The production of a stable recombinant human BMP15 is also important for use in experiments aimed at optimizing ovarian stimulation protocols and in vitro oocyte maturation methods. This is required to improve oocyte and embryonic developmental competence and increase our ability to effectively use in vitro methods for animal production and the treatment of human infertility. PMID:19846464

Mottershead, David G; Watson, Andrew J

2009-10-21

182

Vitrification of oocytes, embryos and blastocysts.  

PubMed

In assisted reproductive technology, cryopreservation of human oocytes and embryos has been significantly improved by refined slow-cooling and the new vitrification method. The slow-cooling method requires a programmed cryo-machine, and usually takes several hours. It is, however, difficult to eliminate injuries resulting from ice formation completely. Vitrification has become a reliable strategy because it is simple, can lead to high survival rates and viability, and has better clinical outcome. Vitrification transforms cells into an amorphous glassy state inside and outside the vitrified cell with ultra-rapid cooling and warming steps by plunging the oocytes and embryos into liquid nitrogen, instead of ice-crystal formation. Over the past decade, several advances in vitrification technologies have improved clinical efficiency and outcome. In this chapter, we focus on vitrification technologies for cryopreservation in human assisted reproductive technology. PMID:22940094

Mukaida, Tetsunori; Oka, Chikahiro

2012-08-31

183

Nuclear Transfer to Eggs and Oocytes  

PubMed Central

We review experiments in which somatic cell nuclei are transplanted singly to enucleated eggs (metaphase II) in amphibia and mammals and as multiple nuclei to the germinal vesicle of amphibian oocytes (prophase I). These experiments have shown the totipotency of some somatic cell nuclei, as well as switches in cell type and changes in gene expression. Abnormalities of nuclear transplant embryo development increase greatly as nuclei are taken from progressively more differentiated donor cells. The molecular changes that accompany the reprogramming of transplanted nuclei help to indicate the mechanisms used by eggs and oocytes to reprogram gene expression. We discuss the importance of chromosomal protein exchange, of transcription factor supply, and of chromatin access in reprogramming.

Gurdon, J. B.; Wilmut, Ian

2011-01-01

184

[Chemical induction -- new strategy of oocyte enucleation].  

PubMed

Mammalian somatic cloning has got great progress during past few years,however,the efficiency of nuclear trasfer remains low. In order to improve this technique, different perspectives of which are studying. Accordingly, the method of oocyte enucleation also becomes a focus. But the physical enucleation is technically demanding, time-consuming, inherently invasive and clearly damaging to cytoplast spatial organization. As a alternative strategy to traditional method, Demecolcine-induced enucleation(IE) attracted the scientist's eyes. Nuclear transfer procedure assited with IE, factors releated with success rate of IE and effects of IE on the oocytes and cloned embryos are mainly discussed in this review. At the same time, combining with author's research, the existing problems of IE and potential improved measures of some key steps in IE procedure are also elucidated. However, the utility of the demecolcine-induced enucleation protocol will require further deep investigation. PMID:15971595

Wang, Qiang; Gu, Ling; Zhang, Yong

2003-11-01

185

In Vitro Maturation of Mammalian Oocytes  

Microsoft Academic Search

\\u000a Efforts to optimize oocyte quality as a result of in vitro maturation (IVM) are critical to achieving patient-specific success\\u000a in assisted reproductive techniques. Traditional approaches to human IVM have been replaced by methodologies aimed at recapitula­ting\\u000a the changing milieu of the ovulatory follicle following reception of signals initiated by LH. These include the deployment\\u000a of sequential media changes that more

John J. Bromfield; Katie L. Jones; David F. Albertini

186

In-vitro Maturation of Human Oocytes  

Microsoft Academic Search

\\u000a Since the birth of the first in-vitro fertilization (IVF) baby in 1978 [1], assisted reproductive technologies (ART) have\\u000a helped thousands of couples to have children through the use of ovarian stimulation [2]. IVF was first performed in a natural\\u000a cycle without any hormonal stimulation, and the oocyte retrieval was performed laparoscopically. However, natural cycle IVF\\u000a was soon replaced by ovarian

Ezgi Demirtas; Hananel Holzer; Weon-Young SON; Ri-Cheng Chain; Seang Lin Tan

187

In vitro oocyte maturation: current status.  

PubMed

Due to its numerous clinical applications, in vitro maturation (IVM) has emerged as a significant topic in the field of assisted reproduction. IVM of germinal vesicle breakdown/metaphase I and germinal vesicle stage oocytes collected from in vitro fertilization (IVF) superovulation cycles are commonly applied with unsatisfactory results. The biological aspect of this so-called rescue in vitro oocyte maturation greatly differs from the actual IVM practice. In the latter, immature oocytes are obtained from small antral follicles of unprimed or minimally stimulated cycles aiming to avoid ovarian hyperstimulation syndrome in high-risk patients or simply as an alternative to conventional IVF in normo-ovulatory patients. Over the past decade, cases reports regarding IVM have been sporadically reported, with ~25 peer-reviewed articles currently available. These studies present variable outcomes and deal with clinical approaches about selecting the most appropriate patient population that could benefit from IVM technology. Although some of the studies are encouraging, the vast majority includes small sample sizes, thus making the data rather inconclusive. As such there is a certain reserve in the IVF community to embark on treatment cycles for IVM in routine use. Laboratory parameters play an important role in the success of IVM, and research for optimal culture conditions is warranted. Existing data from newborns assure us that IVM may be a safe procedure provided in assisted reproductive technology. When optimized, it will serve, not only for infertile patients, but also as a more patient-friendly alternative than standard controlled ovarian stimulation to obtain oocytes for donation or preservation of fecundity. PMID:22585631

Nogueira, Daniela; Sadeu, Jean Clair; Montagut, Jacques

2012-05-14

188

Nongenomic Steroid-Triggered Oocyte Maturation: Of Mice and Frogs  

PubMed Central

Luteinizing hormone (LH) mediates many important processes in ovarian follicles, including cumulus cell expansion, changes in gap junction expression and activity, sterol and steroid production, and the release of paracrine signaling molecules. All of these functions work together to trigger oocyte maturation (meiotic progression) and subsequent ovulation. Many laboratories are interested in better understanding both the extra-oocyte follicular processes that trigger oocyte maturation, as well as the intra-oocyte molecules and signals that regulate meiosis. Multiple model systems have been used to study LH-effects in the ovary, including fish, frogs, mice, rats, pigs, and primates. Here we provide a brief summary of oocyte maturation, focusing primarily on steroid-triggered meiotic progression in frogs and mice. Furthermore, we present new studies that implicate classical steroid receptors rather than alternative non-classical membrane steroid receptors as the primary regulators of steroid-mediated oocyte maturation in both of these model systems.

Deng, James; Carbajal, Liliana; Evaul, Kristen; Rasar, Melissa; Jamnongjit, Michelle; Hammes, Stephen R

2009-01-01

189

Chromosomal FISH analysis of unfertilized human oocytes and polar bodies.  

PubMed

The incidence of chromosomal aneuploidy was studied in 208 unfertilized metaphase II human oocytes from an in vitro fertilization program by fluorescence in situ hybridization using probes for chromosomes 18, 21, and X. Chromosome spreads were prepared by a gradual fixation-air-drying method. We obtained analyzable results from 183 oocytes and 93 polar bodies; 167 oocytes (91%) were normal, 11 (6%) were diploid, and 5 (3%) were aneuploid. Of the five aneuploid oocytes, four involved chromosome 21, and one involved the X chromosome. In this study, oocyte aneuploidy caused by both nondisjunction of bivalent chromosomes and predivision of univalent chromosomes was observed. The aneuploidy rate (9.8%) in the oocytes from women aged >==35 years was significantly higher than that (0.7%) in those aged 23 to 34 years ( P = 0.0017). PMID:12202989

Honda, Nao; Miharu, Norio; Hara, Tetsuaki; Samura, Osamu; Honda, Hiroshi; Ohama, Koso

2002-01-01

190

Deep penetration calculations. [LMFBR  

SciTech Connect

Several Monte Carlo techniques are compared in the transport of neutrons of different source energies through two different deep-penetration problems each with two parts. The first problem involves transmission through a 200-cm concrete slab. The second problem is a 90/sup 0/ bent pipe jacketed by concrete. In one case the pipe is void, and in the other it is filled with liquid sodium. Calculations are made with two different Los Alamos Monte Carlo codes: the continuous-energy code MCNP and the multigroup code MCMG.

Thompson, W.L.; Deutsch, O.L.; Booth, T.E.

1980-04-01

191

Bidirectional communication between oocytes and follicle cells: ensuring oocyte developmental competence  

PubMed Central

Female fertility is determined to a large extent by the quality (developmental competence) of the oocyte as reflected in its ability to undergo meiosis, be fertilized, and give rise to a healthy embryo. Growth of the mammalian oocyte is coordinated with that of the follicle that encloses it by the actions of signals that pass in both directions between the germline and somatic components. This review summarizes what is known about the roles played by two different modes of intrafollicular signalling in oogenesis: paracrine factors activating receptors on the opposite cell type, and direct sharing of small molecules throughout the follicle via gap junction channels. Recent evidence indicates that these two modes of signalling interact to regulate oocyte growth and granulosa cell proliferation, and that defects in either can contribute to female infertility.

Kidder, Gerald M.; Vanderhyden, Barbara C.

2011-01-01

192

Synthesis of Chick Brain GABA Receptors by Frog Oocytes  

Microsoft Academic Search

Poly(A)-mRNA, extracted from the optic lobe of chick embryos, directs the synthesis of gamma -aminobutyric acid (GABA) receptors in Xenopus laevis oocytes. The receptors are inserted into the oocyte membrane, where they form receptor--channel complexes. When activated by GABA, and related agonists, the chick brain receptors open membrane channels that are permeable to chloride ions. Thus, Xenopus oocytes provide a

R. Miledi; I. Parker; K. Sumikawa

1982-01-01

193

Cryopreservation of Mature Bovine Oocytes Following Centrifugation Treatment  

Microsoft Academic Search

In vitromatured bovine oocytes were frozen slowly in 1.6M1,2-propanediol following centrifugation treatment for polarization of lipid droplets in the cytoplasm. After thawing, the survival of the oocytes was assessed morphologically and also byin vitrofertilization and culture. The polarization of cytoplasmic lipid droplets had a negative effect on the survival of frozen-thawed oocytes. Thus, this treatment did not improve the frequency

T. OTOI; K. YAMAMOTO; N. KOYAMA; S. TACHIKAWA; M. MURAKAMI; Y. KIKKAWA; T. SUZUKI

1997-01-01

194

Chromosomal FISH analysis of unfertilized human oocytes and polar bodies  

Microsoft Academic Search

.  ?The incidence of chromosomal aneuploidy was studied in 208 unfertilized metaphase II human oocytes from an in vitro fertilization\\u000a program by fluorescence in situ hybridization using probes for chromosomes 18, 21, and X. Chromosome spreads were prepared\\u000a by a gradual fixation–air-drying method. We obtained analyzable results from 183 oocytes and 93 polar bodies; 167 oocytes\\u000a (91%) were normal, 11 (6%)

Nao Honda; Norio Miharu; Tetsuaki Hara; Osamu Samura; Hiroshi Honda; Koso Ohama

2002-01-01

195

EXPRESSION OF MEMBRANE TRANSPORTERS IN CANE TOAD BUFO MARINUS OOCYTES  

Microsoft Academic Search

Membrane transport proteins (transporters and ion channels) have been extensively expressed in amphibian oocytes. The aims of this study were to determine whether oocytes from the cane toad Bufo marinus could be used as an alternative expression system to the broadly used Xenopus laevis oocytes. mRNAs encoding plasma membrane transporters NaSi-1 and sat-1 (sulphate transporters), NaDC-1 (dicarboxylate transporter), SGLT- 1

DANIEL MARKOVICH; RALF R. REGEER

196

Correlation Between Human Follicular Diameter and Oocyte Outcomes in an ICSI Program  

Microsoft Academic Search

Purpose: To determine the correlation between the follicular sizes and oocyte recovery, metaphase II oocyte recovery, fertilization rate and good embryo quality from mature and immature oocytes in an intracytoplasmic sperm injection (ICSI) program.

Anusorn Triwitayakorn; Somchai Suwajanakorn; Kamthorn Pruksananonda; Wisan Sereepapong; Vichuda Ahnonkitpanit

2003-01-01

197

Skin penetration enhancers.  

PubMed

The skin has evolved to prevent excessive water loss from the internal organs and to limit the ability of xenobiotics and hazardous substances to enter the body. Notwithstanding this barrier function, a number of strategies have been developed by scientists to deliver drugs to and through the skin. The aim of this review is to consider the various types of chemical penetration enhancers (CPEs) which have been investigated in the scientific literature. Potential pathways for CPEs to exert their action are examined with reference to the physical chemistry of passive skin transport. The emphasis is on those studies which have focussed on human and porcine skin because of the limitations associated with skin permeation data collated from other species. Where known, the mechanisms of action of these compounds are also discussed. Examples of enhancers used in commercial topical and transdermal formulations are provided. It is proposed that overall the effects of CPEs on the skin barrier may best be explained by a Diffusion-Partition-Solubility theory. Finally, some of the limitations of studies in the literature are considered and the importance of monitoring the fate of the penetration enhancer as well as the active is highlighted. PMID:23462366

Lane, Majella E

2013-02-24

198

Sand Penetration Experiments  

NASA Astrophysics Data System (ADS)

In an experimental program, steel bullets and short cylinders, and tungsten alloy rods were shot into dry silica sand at 600 to 1100 m/s. The rods included finsets that were designed for aerodynamic stabilization. The fins also apparently provided trajectory stabilization within the sand as well. Time-of-arrival screens allowed measurement of velocity. Analysis of those data indicated that drag coefficients increased as projectiles slowed down. Comparison with previous data indicates there was a slight increase in drag coefficient of rods over expected values for unfinned rods; however, the net result was penetration normalized by length was as high as 40, depending on nose shape. It was found that when the velocity exceeded about 80 m/s (which is close to the speed of sound in sand) sand particles were broken down into their constituent grains, resulting in a decrease in size by about 1000. Normalized penetration is expected to scale as kinetic energy per unit area, and it was significantly higher for the rods than for the other projectiles. This is attributed to stabilization from interaction of the fins with the cavity wall.

Bless, Stephan; Berry, Don; Lawhorn, William

2009-06-01

199

Riboflavin uptake by native Xenopus laevis oocytes.  

PubMed

The existence of a membrane-associated uptake carrier for riboflavin (RF) is demonstrated in Xenopus oocytes. Uptake of low (0.017 microM) and high (3 microM) concentrations of RF was linear with time for up to 2 hours, and occurred with little initial binding to oocytes, and little metabolism. Uptake of RF was found to be independent of extracellular pH and Na+. The initial rate of RF uptake was saturable as a function of concentration with an apparent Km of 0.41 +/- 0.02 microM and a Vmax of 2.86 +/- 0.04 fmol/oocyte per h. Uptake of 3H-RF was inhibited by unlabeled RF and by the structural analogs lumiflavin, isoriboflavin (iso-RF), 8-aminoriboflavin (8-NH2-RF), 8-hydroxyriboflavin (8-OH-RF), and lumichrome, but was not affected by flavin adenine dinucleotide (FAD), D-ribose or lumazine. Uptake of RF was significantly retarded by the metabolic inhibitor 2,4-dinitrophenol. The sulfhydryl group-modifying reagents p-chloromercuriphenylsulfonate (pCMPS), p-chloromercuribenzoate (pCMB), N-ethylmaleimide and 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl) all caused significant inhibition in RF uptake. The inhibitory effect of pCMPS was completely reversed by treatment of pCMPS-pretreated cells with reducing agents. While the transmembrane transport inhibitors 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS), 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) and furosemide had no effect on RF uptake, amiloride and probenecid suppressed RF uptake in a dose-dependent fashion. Closer examination of the inhibition mediated by amiloride showed that it was competitive in nature with an apparent Ki of approximately 1.8 mM, whereas the inhibition induced by probenecid was nonspecific. Together, these findings indicate that Xenopus oocytes possess an endogenous, specific, membrane-associated carrier-mediated uptake system for RF. The results also demonstrate the usefulness of Xenopus oocytes as a model system with which to study the RF transport event across biological membranes, which should further out present understanding of RF uptake by various vertebrate cells. PMID:7880856

Dyer, D L; Said, H M

1995-03-01

200

Oocyte-like cells induced from mouse spermatogonial stem cells  

PubMed Central

Background During normal development primordial germ cells (PGCs) derived from the epiblast are the precursors of spermatogonia and oogonia. In culture, PGCs can be induced to dedifferentiate to pluripotent embryonic germ (EG) cells in the presence of various growth factors. Several recent studies have now demonstrated that spermatogonial stem cells (SSCs) can also revert back to pluripotency as embryonic stem (ES)-like cells under certain culture conditions. However, the potential dedifferentiation of SSCs into PGCs or the potential generation of oocytes from SSCs has not been demonstrated before. Results We report that mouse male SSCs can be converted into oocyte-like cells in culture. These SSCs-derived oocytes (SSC-Oocs) were similar in size to normal mouse mature oocytes. They expressed oocyte-specific markers and gave rise to embryos through parthenogenesis. Interestingly, the Y- and X-linked testis-specific genes in these SSC-Oocs were significantly down-regulated or turned off, while oocyte-specific X-linked genes were activated. The gene expression profile appeared to switch to that of the oocyte across the X chromosome. Furthermore, these oocyte-like cells lost paternal imprinting but acquired maternal imprinting. Conclusions Our data demonstrate that SSCs might maintain the potential to be reprogrammed into oocytes with corresponding epigenetic reversals. This study provides not only further evidence for the remarkable plasticity of SSCs but also a potential system for dissecting molecular and epigenetic regulations in germ cell fate determination and imprinting establishment during gametogenesis.

2012-01-01

201

Molecular cloning and characterization of a hamster Cav1.3 Ca2+ channel variant with a long carboxyl terminus.  

PubMed

We have cloned a hamster Cav1.3 variant with a long carboxyl terminus. This differs from the first hamster Cav1.3 clone which has a short carboxyl terminus. When relative expression levels of the two variants were examined using quantitative RT-PCR, the long Cav1.3 transcripts were detected abundantly in the brain and testis, moderately in the heart, pancreas, and kidney, and weakly in the lung. Comparatively, the short Cav1.3 transcripts were detected less abundantly in most of the tissues. The two Cav1.3 variants were reconstituted in Xenopus oocytes and their electrophysiological properties were characterized using a two-electrode voltage clamping method. The long Cav1.3 variant was ~5-fold better expressed than the short Cav1.3 variant. When Ca2+ was used as a charge carrier, the long Cav1.3 variant containing an IQ (Ile-Gln) motif displayed strong calcium-dependent inactivation, while the short variant that was deficient of an IQ motif showed little calcium-dependent inactivation. Examination of other biophysical properties revealed that potentials for activation threshold, peak current, and half-activation and inactivation of the long Cav1.3 were significantly lower than those of the short Cav1.3. These findings suggest that the long carboxyl tail plays crucial roles in not only facilitating calcium-dependent inactivation, but also improving expression and negative shifting of the activation and inactivation properties. PMID:21093409

Kang, Ho-Won; Park, Jin-Yong; Lee, Jung-Ha

2010-11-17

202

Seasonal aspects of sleep in the Djungarian hamster  

Microsoft Academic Search

BACKGROUND: Changes in photoperiod and ambient temperature trigger seasonal adaptations in the physiology and behaviour of many species, including the Djungarian hamster. Exposure of the hamsters to a short photoperiod and low ambient temperature leads to a reduction of the polyphasic distribution of sleep and waking over the light and dark period. In contrast, a long photoperiod enhances the daily

Svitlana Palchykova; Tom Deboer; Irene Tobler

2003-01-01

203

Daily hoarding opportunity entrains the pacemaker for hamster activity rhythms  

Microsoft Academic Search

The effects on activity rhythms of a daily 30 min opportunity to leave the home cage and hoard seeds from an open field were assessed in Syrian hamsters housed in continuous dim illumination. Six of ten hamsters responded with clear entrainment of their activity rhythms to the hoarding opportunity, as demonstrated by responses to phase shifts and by the onset

B. Rusak; R. E. Mistlberger; B. Losier; C. H. Jones

1988-01-01

204

Photoperiodic Influences on Sexual Behavior in Male Syrian Hamsters  

Microsoft Academic Search

The effect of photoperiodic conditions on sexual behavior was investigated in male Syrian hamsters that were either gonadally intact, or castrated and treated with low doses of testosterone throughout the experiment. Hamsters were exposed to long (LD 16:8) or short (LD 8:16) days for 7 weeks; for the next 8 weeks, either they were exposed to an intermediate daylength (LD

J. B. Powers; E. A. Steel; J. B. Hutchison; M. H. Hastings; J. Herbert; A. P. Walker

1989-01-01

205

Diabetic syndrome in the Chinese hamster induced with monosodium glutamate  

Microsoft Academic Search

Summary Neuronal necrosis in the arcuate and ventromedial hypothalamus regions is easily induced in 1-day-old Chinese hamsters by the administration of monosodium glutamate (MSG). New-born Chinese hamsters injected with MSG showed no sign of obesity, even when grown up, but apparently developed a diabetic syndrome.

K. Komeda; M. Yokote; Y. Oki

1980-01-01

206

CORTICOTROPIN RELEASING FACTOR RECEPTORS AND AGONISTIC BEHAVIOR IN SYRIAN HAMSTERS  

Microsoft Academic Search

Social conflict is a part of everyday life, and it can be a potent stressor for both humans and other animals. In the laboratory, when two Syrian hamsters (Mesocricetus auratus) compete for territory, a dominance hierarchy is quickly formed. Becoming subordinate is a significant stressor resulting in increased release of adrenocorticotropic hormone, ?-endorphin, and cortisol. Defeated hamsters will also subsequently

ALICIA N. FARUZZI

207

Circadian Organization oftau Mutant Hamsters: Aftereffects and Splitting  

Microsoft Academic Search

Homozygous tau mutant (?ss) hamsters show an extremely short (20 h) circadian period (?) that is attributable to altered enzymatic activity of casein kinase 1?. It has been proposed that coupling of constituent circadian oscillators is strengthened in ?ss hamsters, explaining their tendency to show strong resetting after prolonged exposure to constant darkness. To evaluate further the circadian organization of

Eric L. Bittman; Mary K. Costello; Judy McKinley Brewer

2007-01-01

208

Neuroimmunomodulatory Effects of Morphine in Leishmania donovani-Infected Hamsters  

Microsoft Academic Search

Objective: The effect of morphine on host defense during Leishmania donovani infection in golden hamsters was studied. Methods: Hamsters were intracardially infected with L. donovani amastigotes and then monitored by spleen touch print microscopic examination. Morphine and naloxone were administered subcutaneously and intraperitoneally, respectively. Leukocytes were counted by a hemocytometer, and ex vivo phagocytosis was determined by the examination of

Priya Singal; Arvind G. Kinhikar; Savita Singh; Prati Pal Singh

2002-01-01

209

Mouse oocytes enable LH-induced maturation of the cumulus-oocyte complex via promoting EGF receptor-dependent signaling  

Microsoft Academic Search

LH triggers the maturation of the cumulus-oocyte complex (COC), which is followed by ovulation. These ovarian follicular responses to LH are mediated by epidermal growth factor (EGF)-like growth factors produced by granulosa cells and require the participation of oocyte-derived paracrine factors. However, it is not clear how oocytes coordinate with the EGF receptor (EGFR) signaling to achieve COC maturation. The

Y.-Q. Su; K. Sugiura; Q. Li; K. Wigglesworth; M. M. Matzuk; J. J. Eppig

2010-01-01

210

Quantification of oocyte-specific transcripts in follicle-enclosed oocytes during antral development and maturation in vitro.  

PubMed

Oocyte cytoplasmic maturation is influenced by the quantity of synthesized RNA and proteins accumulated and stored during growth. Transcriptional repression and degradation of transcripts occur during oocyte nuclear maturation, and prolonged transcriptional arrest might compromise RNA stores for early development. RNA quantification of key genes in oocytes might be valuable when setting up in vitro cultures that lack the normal hormonal interplay found in vivo. This study quantifies gene expression levels in relation to follicle culture time and time of oocyte maturation in a mouse model. RNA levels of Gdf-9, Bmp-15, Mater, Zar-1, Npm-2 and Fgf-8 were measured in germinal vesicle oocytes along fixed times during in vitro follicle development. For all genes, the highest mRNA levels were detected in oocytes in the pre-antral follicle stage. Antrum formation was associated with a progressive shutdown in transcription leading to mRNA values lower than those in vivo preovulatory oocytes by extending period of in vitro culture. In contrast to in vitro-matured oocytes, the in vivo oocytes from 22- and 29-day-old prepubertal animals obtained after pregnant mare's serum gonadotrophin and human chorionic gonadotrophin priming did not down-regulate transcripts upon maturation stimulus except for Mater. These findings show that oocyte gene expression patterns under in vitro conditions can, at certain times, mimic what is reported to occur under in vivo conditions. Moreover, they also show that meiotically competent oocytes kept in a prolonged transcriptionally inactive stage express altered levels of key transcripts compared with in vivo in both immature and mature oocytes. PMID:19553355

Sánchez, Flor; Adriaenssens, Tom; Romero, Sergio; Smitz, Johan

2009-06-24

211

Oocyte-specific expression of Gpr3 is required for the maintenance of meiotic arrest in mouse oocytes  

PubMed Central

The maintenance of meiotic prophase arrest in mouse oocytes within fully grown follicles, prior to the surge of luteinizing hormone (LH) that triggers meiotic resumption, depends on a high level of cAMP within the oocyte. cAMP is produced within the oocyte, at least in large part, by the Gs-linked G-protein-coupled receptor, GPR3. Gpr3 is localized in the mouse oocyte but is also present throughout the follicle. To investigate whether Gpr3 in the follicle cells contributes to the maintenance of meiotic arrest, RNA interference (RNAi) was used to reduce the amount of Gpr3 RNA within follicle-enclosed oocytes. Follicle-enclosed oocytes injected with small interfering double-stranded RNA (siRNA) targeting Gpr3, but not control siRNAs, stimulated the resumption of meiosis in the majority of oocytes following a 3-day culture period. Reduction of RNA was specific for Gpr3 because an unrelated gene was not reduced by microinjection of siRNA. Meiotic resumption was stimulated in isolated oocytes injected with the same siRNA and cultured for 1 to 2 days, but at a much lower rate than in follicle-enclosed oocytes that could be cultured for longer. These results demonstrate that GPR3 specifically in the oocyte, rather than in the follicle cells, is responsible for maintenance of meiotic arrest in mouse oocytes. Furthermore, the method developed here for specifically reducing RNA in follicle-enclosed oocytes, which can be cultured for a sufficient time to reduce the level of endogenous protein, should be generally useful for targeting a wide range of other proteins that may be involved in meiotic arrest, the resumption of meiosis, fertilization, or early embryonic development.

Mehlmann, Lisa M.

2007-01-01

212

Inhibition of bovine sperm-oocyte fusion by a monoclonal antibody recognising the TEC-2 epitope on bovine oocytes.  

PubMed

The TEC-2 antigenic determinant is a carbohydrate epitope located on a glycoprotein carrier molecule. In the mouse, this epitope is expressed on the zona pellucida and plasma membrane of the oocyte and is associated with the ZP2 glycoprotein and involved in the secondary sperm receptor mechanism. On the bovine oocyte expression is confined to the plasma membrane. The aim of this study was to determine the role the TEC-2 epitope plays during fertilization in the bovine species using the monoclonal antibody TEC-02. Incubating oocytes with the TEC-02 antibody prior to fertilization inhibited cleavage in a dose-dependent manner-the cleavage rate decreased as the concentration of the antibody increased. Significantly more sperm were bound to oocytes exposed to TEC-02 (12 sperm/oocyte) compared to oocytes that were not incubated with the antibody (4 sperm/oocyte). Oocytes treated with the TEC-02 antibody had a 7.5 +/- 3.2% fusion rate and no cortical granule exocytosis compared with oocytes not exposed to the antibody, with 86.5 +/- 5.8% of sperm-oocyte fusions and release of cortical granules. The block to sperm-oocyte fertilization observed in the pretreated group was overcome using intracytoplasmic sperm injection as the method of fertilization that bypassed the fusion process. Although sperm were binding to the oolemma these results suggest that fusion was not occurring and this may be due to the antibody occupying TEC-2 epitope sites involved in the fusion process. In conclusion, the TEC-2 epitope seems to be involved in sperm-oocyte interaction in the bovine species and appears to be involved specifically during the fusion events of fertilization. PMID:10471477

Gougoulidis, T; Trounson, A; Dowsing, A

1999-10-01

213

In Vitro Oocyte Maturation and Preantral Follicle Culture from the Luteal-Phase Baboon Ovary Produce Mature Oocytes1  

PubMed Central

Female cancer patients who seek fertility preservation but cannot undergo ovarian stimulation and embryo preservation may consider 1) retrieval of immature oocytes followed by in vitro maturation (IVM) or 2) ovarian tissue cryopreservation followed by transplantation or in vitro follicle culture. Conventional IVM is carried out during the follicular phase of menstrual cycle. There is limited evidence demonstrating that immature oocyte retrieved during the luteal phase can mature in vitro and be fertilized to produce viable embryos. While in vitro follicle culture is successful in rodents, its application in nonhuman primates has made limited progress. The objective of this study was to investigate the competence of immature luteal-phase oocytes from baboon and to determine the effect of follicle-stimulating hormone (FSH) on baboon preantral follicle culture and oocyte maturation in vitro. Oocytes from small antral follicle cumulus-oocyte complexes (COCs) with multiple cumulus layers (42%) were more likely to resume meiosis and progress to metaphase II (MII) than oocytes with a single layer of cumulus cells or less (23% vs. 3%, respectively). Twenty-four percent of mature oocytes were successfully fertilized by intracytoplasmic sperm injection, and 25% of these developed to morula-stage embryos. Preantral follicles were encapsulated in fibrin-alginate-matrigel matrices and cultured to small antral stage in an FSH-independent manner. FSH negatively impacted follicle health by disrupting the integrity of oocyte and cumulus cells contact. Follicles grown in the absence of FSH produced MII oocytes with normal spindle structure. In conclusion, baboon luteal-phase COCs and oocytes from cultured preantral follicles can be matured in vitro. Oocyte meiotic competence correlated positively with the number of cumulus cell layers. This study clarifies the parameters of the follicle culture system in nonhuman primates and provides foundational data for future clinical development as a fertility preservation option for women with cancer.

Xu, Min; Fazleabas, Asgerally T.; Shikanov, Ariella; Jackson, Erin; Barrett, Susan L.; Hirshfeld-Cytron, Jenny; Kiesewetter, Sarah E.; Shea, Lonnie D.; Woodruff, Teresa K.

2010-01-01

214

Recombination in hamster cell nuclear extracts between adenovirus type 12 DNA and two hamster preinsertion sequences.  

PubMed Central

A cell-free system of nuclear extracts from BHK21 cells has been developed to catalyse recombination in vitro between the DNA of adenovirus type 12 (Ad12) and two different hamster preinsertion sequences. The pBR322 cloned 1768 bp fragment p7 and the 3.1 kbp fragment p16 from BHK21 hamster DNA had previously been identified as the preinsertion sites corresponding to the junctions between Ad12 DNA and hamster DNA in cell line CLAC1 and in the Ad12-induced tumour T1111(2), respectively. Preinsertion sequences, which had recombined previously with foreign (Ad12) DNA, might again be recognized by the recombination system even in a cell-free system. PstI cleaved Ad12 DNA and the circular or the EcoRI linearized p7 or p16 preinsertion sequences were incubated with nuclear extracts. Recombinants were isolated by transfecting the DNA into recA- Escherichia coli strains and by screening for Ad12 DNA-positive colonies. Without a selectable eukaryotic marker, all Ad12 DNA positive recombinants were registered. Out of a total of greater than 90 p7-Ad12 DNA recombinants, 21 were studied by restriction-hybridization, and four by partial nucleotide sequence analyses. Among the p16-Ad12 DNA recombinants, four were analysed. The sites of linkage between Ad12 DNA and p7 or p16 hamster DNA were all different and distinct from the original CLAC1 or T1111(2) junction site between Ad12 and hamster DNA. The in vitro recombinants were not generated by simple end-to-end joining of the DNA fragments used in the reaction but by genetic exchange. Thirteen of the 25 recombinants were derived from the 61-71 map unit fragment of Ad12 DNA. Recombination experiments between Ad12 DNA and four randomly selected unique or repetitive hamster DNA sequences of 1.5-6.2 kbp in length did not yield recombinants. Apparently, the p7 and p16 hamster preinsertion sequences recombined with Ad12 DNA with a certain preference. Images

Jessberger, R; Heuss, D; Doerfler, W

1989-01-01

215

Blood nicotine levels in hamsters after smoking and subcutaneous nicotine.  

PubMed

Information is limited on blood nicotine levels among laboratory animals subjected to smoking or nicotine injections. This study was done to provide such information on blood nicotine levels in hamsters to better investigate nicotine-related pathology, using levels similar to those of human smokers. Blood nicotine levels were quantitated by gas chromatography and mass spectrophotometry among adult hamsters smoking one of three different strength cigarettes and hamsters injected with four different doses of subcutaneous nicotine, and their controls. The recorded levels rose dose dependently with increasing cigarette strengths and increasing doses of injected nicotine. Based upon regression equations, blood nicotine levels in the hamster model approximating human habitual ad lib. smoking are achieved by using a 1.56-mg nicotine cigarette or injecting 0.15 mg/kg nicotine. The Syrian golden hamster provides a good model for acute or chronic studies involving cigarette smoking. PMID:3398539

Keith, I M

1988-07-01

216

Absence of MSY2 in Mouse Oocytes Perturbs Oocyte Growth and Maturation, RNA Stability, and the Transcriptome1  

PubMed Central

Messenger RNA is remarkably stable during oocyte growth, thus enabling mRNAs to accumulate during the growth phase and thereby provide mRNAs that support early embryonic development. MSY2, a germ cell-specific RNA-binding protein, is implicated in regulating mRNA stability. MSY2 is essential for development because female Msy2?/? mice are infertile. We describe here the characterization of Msy2?/? oocytes. Mutant oocytes grow more slowly during the first wave of folliculogenesis, and maturation to and arrest at metaphase II is severely compromised because of aberrant spindle formation and chromosome congression. Consistent with MSY2 conferring mRNA stability is that the amount of poly(A)-containing RNA is reduced by ?25% in mutant oocytes. Stability of an exogenous mRNA injected into mutant oocytes is lower than when compared to their wild-type counterparts, and moreover, expression of wild-type MSY2 in mutant oocytes increases mRNA stability, whereas injection of a mutant form of MSY2 not capable of binding RNA does not. Transcription quiescence that normally occurs during the course of oocyte growth is not observed in mutant oocytes, and the transcriptome of mutant oocytes is markedly perturbed. These results, and those of previous studies, strongly implicate a central role of MSY2 in regulating mRNA stability.

Medvedev, Sergey; Pan, Hua; Schultz, Richard M.

2011-01-01

217

Cell volume regulation is initiated in mouse oocytes after ovulation.  

PubMed

Fertilized mouse eggs regulate their size principally by accumulating glycine as an intracellular osmolyte using the GLYT1 (SLC6A9) transporter, a mechanism of cell volume homeostasis apparently unique to early embryos before the morula stage. However, nothing was known of cell volume regulation in oocytes before fertilization. We show here that GLYT1 is quiescent in mouse germinal-vesicle-stage oocytes but becomes fully activated within hours after ovulation is triggered. This initiates accumulation of substantial amounts of intracellular glycine in oocytes during meiotic progression, reaching a maximal level in mature eggs. Measurements of endogenous free glycine showed that there were nearly undetectable levels in ovarian germinal-vesicle-stage oocytes, but high levels were present in mature ovulated eggs and in preimplantation embryos through the two-cell stage, but not in morulae. Furthermore, intracellular glycine was regulated in response to changes in external tonicity in eggs and embryos through the two-cell stage, but not in oocytes or embryos after the two-cell stage. Before activation of GLYT1, oocytes were unable to independently regulate their volume. As GLYT1 became active, however, oocyte volume decreased substantially and oocytes gained the ability to regulate their size, which required GLYT1 activity. Before ovulation, oocyte size was instead determined by a strong adhesion to the rigid extracellular matrix of the oocyte, the zona pellucida, which was released coincident with GLYT1 activation. The ability to acutely regulate cell size is thus acquired by the oocyte only after ovulation, when it first develops glycine-dependent cell volume regulation. PMID:19502485

Tartia, Alina P; Rudraraju, Nirmala; Richards, Tiffany; Hammer, Mary-Anne; Talbot, Prudence; Baltz, Jay M

2009-07-01

218

NITRIC OXIDE EXTENDS THE OOCYTE TEMPORAL WINDOW FOR OPTIMAL FERTILIZATION  

PubMed Central

Deteriorating oocyte quality is a critical hurdle in the management of infertility, especially one associated with advancing age. In this study, we explore the role of nitric oxide (NO) on the sustenance of oocyte quality post-ovulation. Sibling oocytes from superovulated mice were subjected to intracytoplasmic sperm injection (ICSI) with cauda-epididymal spermatozoa following exposure to either the NO donor, S-nitroso N-acetyl penicillamine (SNAP, 0.23 ?M/min); an NO synthase (NOS) inhibitor, N?-nitro-L-arginine methyl ester (L-NAME, 1 mM), or an inhibitor of soluble guanylyl cyclase (sGC), 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ, 100 ?M) and their sibling oocytes were subjected to ICSI either before (young) or after culture for the corresponding period of time (old). Outcomes of normal fertilization, cleavage and development to the morula and blastocyst stages were compared. Embryos from each subgroup were also subjected to TUNEL assay for apoptosis. A significant deterioration in the ability of the oocytes to undergo normal fertilization and development to morula and blastocyst stages occurred among oocytes aged in culture medium compared to their sibling cohorts subjected to ICSI immediately after ovulation (P<0.05). This deterioration was prevented in oocytes exposed to SNAP. In contrast, exposure to L-NAME or ODQ resulted in a significant compromise in fertilization and development to the morula and blastocyst stages (P<0.05). Finally, apoptosis was noted in embryos derived from aged oocytes and those exposed to L-NAME or ODQ, but not in embryos derived from young oocytes or oocytes exposed to SNAP. Thus, NO is essential for sustenance of oocyte quality post-ovulation.

GOUD, PRAVIN T.; GOUD, ANURADHA P.; DIAMOND, MICHAEL P.; GONIK, BERNARD; ABU-SOUD, HUSAM M.

2012-01-01

219

Fertilization and pregnancy potential of immature oocytes from stimulated intracytoplasmic sperm injection cycles  

PubMed Central

Objective We evaluated the fertilization potential of immature oocytes obtained from controlled ovarian hyperstimulation cycles of patients undergoing ICSI. Methods We retrospectively analyzed 463 ICSI cycles containing at least one immature oocyte at oocyte denudation. ICSI was performed on mature oocytes at oocyte denudation (metaphase-II [MII] oocytes) and the oocytes that extruded the first polar body between oocyte denudation and ICSI (MI-MII oocytes). Fertilization and early embryonic development were compared between MII and MI-MII oocytes. To investigate the pregnancy potential of MI-MII oocytes, the pregnancy outcome was analyzed in 24 ICSI cycles containing only immature oocytes at retrieval. Results The fertilization rate of MI-MII oocytes (37.0%) was significantly lower than that of MII oocytes (72.3%). The rates of delayed embryos and damaged embryos did not significantly differ. Eighty-one immature oocytes were retrieved in 24 cycles that retrieved only immature oocytes and 61 (75.3%) of them were in the MI stage. ICSI was performed on 36 oocytes (59.0%) that extruded the first polar body before ICSI and nine MI-MII oocytes (25.0%) were fertilized. Embryo transfers were performed in five cycles. Pregnancy was observed in one cycle, but it ended in biochemical pregnancy. Conclusion In ICSI cycles, oocytes that extruded the first polar body between denudation and ICSI can be used as a source of oocytes for sperm injection. However, their fertilization and pregnancy potential are lower than that of mature oocytes. Therefore, ovarian stimulation should be performed carefully for mature oocytes obtained at retrieval, especially in cycles with a small number of retrieved oocytes.

Shin, Seung Bi; Cho, Jae Won; Lee, Sun-Hee; Yang, Kwang Moon; Lim, Chun Kyu

2013-01-01

220

Visualizing collision effects between penetrating and non-penetrating objects  

Microsoft Academic Search

We present a novel method for visualizing collisions effects between penetrating or non-penetrating objects. The interaction of 3D objects has been traditionally divided into two stages: the detection of a collision, and the response or effects after the collision. In this work, we concern ourselves with the latter. The rendering of collision effects is useful for virtual sculpting, virtual reality,

Carlos D. Correa; Deborah Silver

2007-01-01

221

Universal penetration test apparatus with fluid penetration sensor  

DOEpatents

A universal penetration test apparatus for measuring resistance of a material to a challenge fluid. The apparatus includes a pad saturated with the challenge fluid. The apparatus includes a compression assembly for compressing the material between the pad and a compression member. The apparatus also includes a sensor mechanism for automatically detecting when the challenge fluid penetrates the material.

Johnson, Phillip W. (Rochester, MN); Stampfer, Joseph F. (Santa Fe, NM); Bradley, Orvil D. (Santa Fe, NM)

1999-01-01

222

Universal penetration test apparatus with fluid penetration sensor  

DOEpatents

A universal penetration test apparatus is described for measuring resistance of a material to a challenge fluid. The apparatus includes a pad saturated with the challenge fluid. The apparatus includes a compression assembly for compressing the material between the pad and a compression member. The apparatus also includes a sensor mechanism for automatically detecting when the challenge fluid penetrates the material. 23 figs.

Johnson, P.W.; Stampfer, J.F.; Bradley, O.D.

1999-02-02

223

Provisional assignment of MPI, PKM2, PGM3 , and ME1 to Chinese hamster chromosome 4  

Microsoft Academic Search

Concordant segregation analysis of Chinese hamster (Cricetulus griseus) isozymes and chromosomes segregating from hamster X mouse interspecific somatic cell hybrids revealed that loci for ME1, PGM3, MPI, and PKM2 are located on Chinese hamster chromosome 4. Synteny of these loci in hamsters provides additional evidence for the conservation of mammalian autosomal linkage groups.

Raymond L. Stallings; Gerald M. Adair; Michael J. Siciliano

1984-01-01

224

Regulation of oocyte maturation in fish.  

PubMed

A period of oocyte growth is followed by a process called oocyte maturation (the resumption of meiosis) which occurs prior to ovulation and is a prerequisite for successful fertilization. Our studies using fish models have revealed that oocyte maturation is a three-step induction process involving gonadotropin (LH), maturation-inducing hormone (MIH), and maturation-promoting factor (MPF). LH acts on the ovarian follicle layer to produce MIH (17alpha, 20beta-dihydroxy-4-pregnen-3-one, 17alpha, 20beta-DP, in most fishes). The interaction of ovarian thecal and granulosa cell layers (two-cell type model), is required for the synthesis of 17alpha,20beta-DP. The dramatic increase in the capacity of postvitellogenic follicles to produce 17alpha,20beta-DP in response to LH is correlated with decreases in P450c17 (P450c17-I) and P450 aromatase (oP450arom) mRNA and increases in the novel form of P450c17 (P450c17-II) and 20beta-hydroxysteroid dehydrogenase (20beta-HSD) mRNA. Transcription factors such as Ad4BP/SF-1, Foxl2, and CREB may be involved in the regulation of expression of these steroidogenic enzymes. A distinct family of G-protein-coupled membrane-bound MIH receptors has been shown to mediate non-genomic actions of 17alpha, 20beta-DP. The MIH signal induces the de novo synthesis of cyclin B from the stored mRNA, which activates a preexisting 35 kDa cdc2 kinase via phosphorylation of its threonine 161 by cyclin-dependent kinase activating kinase, thus producing the 34 kDa active cdc2 (active MPF). Upon egg activation, MPF is inactivated by degradation of cyclin B. This process is initiated by the 26S proteasome through the first cut in its NH(2) terminus at lysine 57. PMID:18482399

Nagahama, Yoshitaka; Yamashita, Masakane

2008-05-13

225

Reprogramming of Human Somatic Cells Using Human and Animal Oocytes  

Microsoft Academic Search

There is renewed interest in using animal oocytes to reprogram human somatic cells. Here we compare the re- programming of human somatic nuclei using oocytes obtained from animal and human sources. Comparative analysis of gene expression in morula-stage embryos was carried out using single-embryo transcriptome am- plification and global gene expression analyses. Genomic DNA fingerprinting and PCR analysis confirmed that

Young Chung; Colin E. Bishop; Nathan R. Treff; Stephen J. Walker; Vladislav M. Sandler; Sandy Becker; Irina Klimanskaya; Wan-Song Wun; Randall Dunn; Rebecca M. Hall; Jing Su; Shi-Jiang Lu; Marc Maserati; Young-Ho Choi; Richard Scott; Anthony Atala; Ralph Dittman; Robert Lanza

2009-01-01

226

Mural granulosa cell gene expression associated with oocyte developmental competence  

Microsoft Academic Search

BACKGROUND: Ovarian follicle development is a complex process. Paracrine interactions between somatic and germ cells are critical for normal follicular development and oocyte maturation. Studies have suggested that the health and function of the granulosa and cumulus cells may be reflective of the health status of the enclosed oocyte. The objective of the present study is to assess, using an

Jin-Yi Jiang; Huiling Xiong; Mingju Cao; Xuhua Xia; Marc-Andre Sirard; Benjamin K Tsang

2010-01-01

227

XGef mediates early CPEB phosphorylation during Xenopus oocyte meiotic maturation.  

PubMed

Polyadenylation-induced translation is an important regulatory mechanism during metazoan development. During Xenopus oocyte meiotic progression, polyadenylation-induced translation is regulated by CPEB, which is activated by phosphorylation. XGef, a guanine exchange factor, is a CPEB-interacting protein involved in the early steps of progesterone-stimulated oocyte maturation. We find that XGef influences early oocyte maturation by directly influencing CPEB function. XGef and CPEB interact during oogenesis and oocyte maturation and are present in a c-mos messenger ribonucleoprotein (mRNP). Both proteins also interact directly in vitro. XGef overexpression increases the level of CPEB phosphorylated early during oocyte maturation, and this directly correlates with increased Mos protein accumulation and acceleration of meiotic resumption. To exert this effect, XGef must retain guanine exchange activity and the interaction with CPEB. Overexpression of a guanine exchange deficient version of XGef, which interacts with CPEB, does not enhance early CPEB phosphorylation. Overexpression of a version of XGef that has significantly reduced interaction with CPEB, but retains guanine exchange activity, decreases early CPEB phosphorylation and delays oocyte maturation. Injection of XGef antibodies into oocytes blocks progesterone-induced oocyte maturation and early CPEB phosphorylation. These findings indicate that XGef is involved in early CPEB activation and implicate GTPase signaling in this process. PMID:15635100

Martínez, Susana E; Yuan, Lei; Lacza, Charlemagne; Ransom, Heather; Mahon, Gwendolyn M; Whitehead, Ian P; Hake, Laura E

2005-01-05

228

Fertilizability and developmental capacity of individually cultured bovine oocytes  

Microsoft Academic Search

Culture of single oocytes throughout in vitro maturation (IVM), fertilization (IVF) and culture (IVC) provides detailed information on maturity, fertilizability and developmental capacity of individual bovine oocytes and embryos. In the present study, effects of sperm concentration (Experiment 1), microdrop size (Experiment 2), and the addition of hypotaurine (HT) or glutathione (GSH; Experiment 3) during IVF were investigated. In Experiment

Y. Fukui; Y. Kikuchi; H. Kondo; S. Mizushima

2000-01-01

229

Nuclear competence for maturation and pronuclear formation in mouse oocytes  

Microsoft Academic Search

BACKGROUND: In response to gonadotrophins, a fully grown mouse oocyte matures to the metaphase of the second meiotic division and becomes competent for the development of female and male pronuclei after fertilization. The present study was carried out to clarify when during the growth period an oocyte nucleus acquires the ability to promote pronuclei formation after fertilization. METHODS: Fully grown

Siqin Bao; Yayoi Obata; Yukiko Ono; Nana Futatsumata; Shueo Niimura; Tomohiro Kono

2002-01-01

230

Chicken oocyte growth: receptor-mediated yolk deposition  

Microsoft Academic Search

During the rapid final stage of growth, chicken oocytes take up massive amounts of plasma components and convert them to yolk. The oocyte expresses a receptor that binds both major yolk lipoprotein precursors, vitellogenin (VTG) and very low density lipoprotein (VLDL). In the present study, in vivo transport tracing methodology, isolation of coated vesicles, ligand- and immuno-blotting, and ultrastructural immunocytochemistry

Xinvi Shen; Ernst Steyrer; Helmut Retzek; Esmond J. Sanders; Wolfgang J. Schneider

1993-01-01

231

PROTEIN UPTAKE IN THE OOCYTES OF THE CECROPIA MOTH  

Microsoft Academic Search

The formation of yolk spheres in the oocyte of the cecropia moth, Hyalophora cecropia (L.), is known immunologically to result largely from uptake of a sex-limited blood protein. Recent electron microscope analyses of insect and other animal oocytes have demonstrated fine structural configurations consistent with uptake of proteins by pinocytosis. An electron microscope analysis of the cecropia ovary confirms the

BARBARA STAY

2009-01-01

232

Induction and inhibition of oocyte maturation by EDCs in zebrafish  

PubMed Central

Background Oocyte maturation in lower vertebrates is triggered by maturation-inducing hormone (MIH), which acts on unidentified receptors on the oocyte surface and induces the activation of maturation-promoting factor (MPF) in the oocyte cytoplasm. We previously described the induction of oocyte maturation in fish by an endocrine-disrupting chemical (EDC), diethylstilbestrol (DES), a nonsteroidal estrogen. Methods In this study, stimulatory and inhibitory effects of EDCs and natural steroids on oocyte maturation were examined in zebrafish. For effective agents, some details about the mechanism in induction or inhibition of maturation were examined. Possible groups of DES interacting with the MIH receptor are discussed based on relative potency of steroids to induce maturation. Results Among agents tested, tamoxifen (TAM) and its metabolite 4-hydroxytamoxifen (4-OHT) showed stimulatory activity similar to DES. The time courses of the change in germinal vesicle breakdown and an intracellular molecular event (the synthesis of cyclin B) induced by TAM were indistinguishable from those induced by MIH. In contrast, pentachlorophenol (PCP) had a potent inhibitory effect on MIH-induced oocyte maturation. PCP inhibited not only MIH-induced maturation but also DES- and TAM-induced maturation. Methoxychlor also inhibited maturation when oocytes were pre-treated with this agent. Conclusion These results suggest that EDCs act as agonists or antagonists in the induction of oocyte maturation in fish.

Tokumoto, Toshinobu; Tokumoto, Mika; Nagahama, Yoshitaka

2005-01-01

233

Criteria to assess human oocyte quality after cryopreservation  

Microsoft Academic Search

Oocyte cryopreservation certainly represents one of the most attractive developments in the field of assisted reproduction, with the aim of preserving female fertility and circumventing the ethical and legal drawbacks associated with embryo freezing. Despite the achievement of the first pregnancy from frozen oocytes dating back as early as 1987, since then fewer than 150 pregnancies have been reported. Over

G Coticchio; MA Bonu; V Bianchi; C Flamigni; A Borini

2005-01-01

234

Semen donor recruitment in an oocyte donation programme  

Microsoft Academic Search

The article presents a new system for the recruitment of gamete donors. The system is a partial application of the mirror exchange system: the male partner of a couple donates sperm, and in return, he receives the guarantee that his partner benefits from a greatly reduced waiting time for donor oocytes. More specifically, the woman will obtain donor oocytes within

Anna Pia Ferraretti; Guido Pennings; Luca Gianaroli; Maria Cristina Magli

2006-01-01

235

Factors influencing the obstetric and perinatal outcome after oocyte donation  

Microsoft Academic Search

BACKGROUND: We evaluated interactions between perinatal outcome after oocyte donation and various maternal factors. METHODS: The study included 134 parturients after oocyte donation. Data were collected from medical files and personal interviews. Stepwise logistic regression analyses were used to evaluate associations between perinatal outcomes and selected maternal variables. RESULTS: Fifty percent of the women were >43 years old, 30.6% were

Galit Sheffer-Mimouni; Shlomo Mashiach; Jehoshua Dor; David Levran; Daniel S. Seidman

236

Hormonal control of mammalian oocyte meiosis at diplotene stage.  

PubMed

Mammalian oocytes grow and undergo meiosis within ovarian follicles. Fully grown oocytes are arrested at the first meiotic prophase by a mural granulosa origin "arrester" until a surge of luteinizing hormone (LH) from the pituitary at the mid-cycle stimulates the immature oocyte to resume meiosis. Recent evidence indicates that natriuretic peptide precursor type C (NPPC) produced by mural granulosa cells stimulates the generation of cyclic guanosine 3',5'-monophosphate (cGMP) by cumulus cell natriuretic peptide receptor 2 (NPR2), which diffuses into oocyte via gap junctions and inhibits oocyte phosphodiesterase 3A (PDE3A) activity and cyclic adenosine 3',5'-monophosphate (cAMP) hydrolysis and maintains meiotic arrest with a high intraoocyte cAMP level. This cAMP is generated through the activity of the Gs G-protein by the G-protein-coupled receptor, GPR3 and GPR12, and adenylyl cyclases (ADCY) endogenous to the oocyte. Further studies suggest that endocrine hormones, such as follicle-stimulating hormone (FSH), LH, 17?-estradiol (E2) and oocyte-derived paracrine factors (ODPFs), participate in oocyte meiosis possibly by the regulation of NPPC and/or NPR2. A detailed investigation of NPPC and NPR2 expression in follicle cells will elucidate the precise molecular mechanisms of gonadotropins, and control the arrest as well as resumption of meiosis. PMID:22045555

Zhang, Meijia; Xia, Guoliang

2011-11-02

237

Oxidative stress and ageing of the post-ovulatory oocyte.  

PubMed

With extended periods of time following ovulation, the metaphase II stage oocyte experiences deterioration in quality referred to as post-ovulatory oocyte ageing. Post-ovulatory ageing occurs both in vivo and in vitro and has been associated with reduced fertilization rates, poor embryo quality, post-implantation errors and abnormalities in the offspring. Although the physiological consequences of post-ovulatory oocyte ageing have largely been established, the molecular mechanisms controlling this process are not well defined. This review analyses the relationships between biochemical changes exhibited by the ageing oocyte and the symptoms associated with the ageing phenotype. We also discuss molecular events that are potentially involved in orchestrating post-ovulatory ageing with a particular focus on the role of oxidative stress. We propose that oxidative stress may act as the initiator for a cascade of events that create the aged oocyte phenotype. Specifically, oxidative stress has the capacity to cause a decline in levels of critical cell cycle factors such as maturation-promoting factor, impair calcium homoeostasis, induce mitochondrial dysfunction and directly damage multiple intracellular components of the oocyte such as lipids, proteins and DNA. Finally, this review addresses current strategies for delaying post-ovulatory oocyte ageing with a particular focus on the potential use of compounds such as caffeine or selected antioxidants in the development of more refined media for the preservation of oocyte integrity during IVF procedures. PMID:23950493

Lord, Tessa; Aitken, R John

2013-10-21

238

Two types of intrinsic muscarinic responses in Xenopus oocytes  

Microsoft Academic Search

Fully grown Xenopus laevis oocytes display marked morphological asymmetry. The giant cell is divided into animal (pigmented) and vegetal hemispheres. We have developed methodology aimed at easy determination of hemispheric responses to the application of acetylcholine (ACh) and determination of the distribution of muscarinic receptors. Oocytes of common donors exhibit muscarinic responses that are similar when either the animal or

Noa Matus-Leibovitch; Monica Lupu-Meiri; Yoram Oron

1990-01-01

239

Gene amplification in the oocytes of dytiscid water beetles  

Microsoft Academic Search

A conspicuous mass of extrachromosomal DNA (Giardina's body) is found in oogonia and oocytes of Dytiscid water beetles. Since in older oocytes this DNA is associated with numerous nucleoli, it seemed probable that the ovary might contain extra copies of the genes for ribosomal RNA (rRNA). This hypothesis has been confirmed by centrifugation and molecular hybridization studies. —In Dytiscus marginalis

Joseph G. Gall; Herbert C. Macgregor; Mary Elizabeth Kidston

1969-01-01

240

Amyloids protect the silkmoth oocyte and embryo.  

PubMed

Chorion is the major component of silkmoth eggshell. More than 95% of its dry mass consists of proteins that have remarkable mechanical and chemical properties protecting the oocyte and the developing embryo from a wide range of environmental hazards. We present data from electron microscopy (negative staining and shadowing), X-ray diffraction and modeling studies of synthetic peptide analogues of silkmoth chorion proteins indicating that chorion is a natural amyloid. The folding and self-assembly models of chorion peptides strongly support the beta-sheet helix model of amyloid fibrils proposed recently by Blake and Serpell [Structure 4 (1996) 989-998]. PMID:10981723

Iconomidou, V A; Vriend, G; Hamodrakas, S J

2000-08-18

241

Spindle and Chromosomal Alterations in Metaphase II Oocytes.  

PubMed

The spindle apparatus is a vital structure and must be structurally intact for proper segregation of the oocyte's genetic material during metaphase II. Endometriosis, oxidative stress, and cryopreservation can all adversely affect the structural integrity of the spindle, potentially resulting in aneuploidy and spontaneous abortion of the embryo. Advances in spindle imagery have made it possible to visualize the effects of environmental stresses on spindle structure. Deviation from an oocyte's normal environment can seriously impair the positioning and integrity of the spindle. Oocytes cryopreservation causes depolymerization and repolymerization of the spindle. Oocytes can also be preserved in an immature state for later in vitro maturation. A comprehensive understanding of the spindle behavior is paramount for the effective manipulation of oocytes in an assisted reproductive setting. PMID:23536572

Sharma, Rakesh K; Azeem, Ali; Agarwal, Ashok

2013-03-27

242

The use of antisense oligonucleotides in Xenopus oocytes.  

PubMed

The ability to manipulate gene expression in Xenopus oocytes and then generate fertilized embryos by transfer into host females has made it possible to rapidly characterize maternal signaling pathways in vertebrate development. Maternal mRNAs in particular can be efficiently depleted using antisense deoxyoligonucleotides (oligos), mediated by endogenous RNase-H activity. Since the microinjection of antisense reagents or mRNAs into eggs after fertilization often fails to affect maternal signaling pathways, mRNA depletion in the Xenopus oocyte is uniquely suited to assessing maternal functions. In this review, we highlight the advantages of using antisense in Xenopus oocytes and describe basic methods for designing and choosing effective oligos. We also summarize the procedures for fertilizing cultured oocytes by host-transfer and interpreting the specificity of antisense effects. Although these methods can be technically demanding, the use of antisense in oocytes can be used to address biological questions that are intractable in other experimental settings. PMID:20045732

Hulstrand, Alissa M; Schneider, Patricia N; Houston, Douglas W

2010-01-05

243

Xenopus oocyte meiosis lacks spindle assembly checkpoint control  

PubMed Central

The spindle assembly checkpoint (SAC) functions as a surveillance mechanism to detect chromosome misalignment and to delay anaphase until the errors are corrected. The SAC is thought to control mitosis and meiosis, including meiosis in mammalian eggs. However, it remains unknown if meiosis in the eggs of nonmammalian vertebrate species is also regulated by SAC. Using a novel karyotyping technique, we demonstrate that complete disruption of spindle microtubules in Xenopus laevis oocytes did not affect the bivalent-to-dyad transition at the time oocytes are undergoing anaphase I. These oocytes also acquired the ability to respond to parthenogenetic activation, which indicates proper metaphase II arrest. Similarly, oocytes exhibiting monopolar spindles, via inhibition of aurora B or Eg5 kinesin, underwent monopolar anaphase on time and without additional intervention. Therefore, the metaphase-to-anaphase transition in frog oocytes is not regulated by SAC.

Shao, Hua; Ma, Chunqi; Chen, Eric

2013-01-01

244

Human oocytes reprogram somatic cells to a pluripotent state.  

PubMed

The exchange of the oocyte's genome with the genome of a somatic cell, followed by the derivation of pluripotent stem cells, could enable the generation of specific cells affected in degenerative human diseases. Such cells, carrying the patient's genome, might be useful for cell replacement. Here we report that the development of human oocytes after genome exchange arrests at late cleavage stages in association with transcriptional abnormalities. In contrast, if the oocyte genome is not removed and the somatic cell genome is merely added, the resultant triploid cells develop to the blastocyst stage. Stem cell lines derived from these blastocysts differentiate into cell types of all three germ layers, and a pluripotent gene expression program is established on the genome derived from the somatic cell. This result demonstrates the feasibility of reprogramming human cells using oocytes and identifies removal of the oocyte genome as the primary cause of developmental failure after genome exchange. PMID:21979046

Noggle, Scott; Fung, Ho-Lim; Gore, Athurva; Martinez, Hector; Satriani, Kathleen Crumm; Prosser, Robert; Oum, Kiboong; Paull, Daniel; Druckenmiller, Sarah; Freeby, Matthew; Greenberg, Ellen; Zhang, Kun; Goland, Robin; Sauer, Mark V; Leibel, Rudolph L; Egli, Dieter

2011-10-05

245

Percutaneous penetration of hair dyes  

Microsoft Academic Search

Scalp penetration of 7 hair dyes (oxidative and direct) that occurs under conditions of hair dye usage was evaluated for both rhesus monkey and man using 14C labeled materials by quantifying their absorbtion via urine assays. Both species showed a remarkably similar pattern of dye penetration. The extent of scalp penetratoon is slightly higher for direct dyes but in neither

L. J. Wolfram; H. I. Maibach

1985-01-01

246

Egg penetration By Campylobacter Jejuni  

Microsoft Academic Search

Hens eggs were immersed in suspensions of Campylobacter jejuni (4 strains) and examined for penetration and infection. Penetration was demonstrated using an egg moulding technique and by culture. C. jejuni was recovered from shell membranes, but not from the albumin or yolk. Embryonic deaths were not significantly greater in test than control eggs. Unlike a strain of Salmonella virchow, which

S. D. Neill; J. N. Campbell; J. J. Obrien

1985-01-01

247

Normal Fuze Impact and Penetration.  

National Technical Information Service (NTIS)

A model for the penetration through a thin target by a fuzed projectile at normal incidence was developed. It was assumed that the penetration mechanisms were plugging followed by petalling. From this model the force and stress distributions acting on the...

P. Gordon F. Lee M. Schwartz

1975-01-01

248

Cyclooxygenase-2 expression in hamster and human pancreatic neoplasia.  

PubMed

Cyclooxygenase-2 (COX-2) has been implicated in the development of gastrointestinal malignancies. The aim of the present study was to determine COX-2 expression/activity throughout stages of experimental and human pancreatic neoplasia. COX-2 immunohistochemistry was performed in pancreata of hamsters subjected to the carcinogen N-nitrosobis-(2-oxopropyl)amine (BOP) and in human pancreatic tumors. COX-2 activity was determined by prostaglandin E2 assay in tumor versus matched normal pancreatic tissues. The activity of the COX inhibitor sulindac was tested in the PC-1 hamster pancreatic cancer model. COX-2 expression was elevated in all pancreatic intraepithelial neoplasias (PanINs) and adenocarcinomas. In BOP-treated hamsters, there were significant progressive elevations in COX-2 expression throughout pancreatic tumorigenesis. In human samples, peak COX-2 expression occurred in PanIN2 lesions and remained moderately elevated in PanIN3 and adenocarcinoma tissues. COX-2 activity was significantly elevated in hamster and human pancreatic cancers compared to pair-matched normal pancreas. Furthermore, hamster pancreatic tumor engraftment/formation in the PC-1 hamster pancreatic cancer model was reduced 4.9-fold by oral administration of sulindac. Increased COX-2 expression is an early event in pancreatic carcinogeneses. The BOP-induced hamster carcinogenesis model is a representative model used to study the role of COX-2 in well-differentiated pancreatic tumorigenesis. COX inhibitors may have a role in preventing tumor engraftment/formation. PMID:16820089

Crowell, Pamela L; Schmidt, C Max; Yip-Schneider, Michele T; Savage, Jesse J; Hertzler, Dean A; Cummings, William O

2006-06-01

249

An Earth Penetrating Modeling Assessment  

SciTech Connect

Documentation of a study to assess the capability of computer codes to predict lateral loads on earth penetrating projectiles under conditions of non-normal impact. Calculations simulated a set of small scale penetration tests into concrete targets with oblique faces at angles of 15 and 30 degrees to the line-of-flight. Predictive codes used by the various calculational teams cover a wide range of modeling approaches from approximate techniques, such as cavity expansion, to numerical methods, such as finite element codes. The modeling assessment was performed under the auspices of the Phenomenology Integrated Product Team (PIPT) for the Robust Nuclear Earth Penetrator Program (RNEP). Funding for the penetration experiments and modeling was provided by multiple earth penetrator programs.

Stokes, E; Yarrington, P; Glenn, L

2005-06-21

250

CORTICAL CHANGES IN GROWING OOCYTES AND IN FERTILIZED OR PRICKED EGGS OF RANA PIPIENS  

PubMed Central

The folded cortex of the growing oocyte of the frog extends as microvilli into the substance of the developing vitelline membrane and, internal to the folds, possesses a layer of cortical granules. Free ribosomes, smooth-walled vesicles, coated vesicles, tubules, and electron-opaque granules are abundant in the peripheral zone of the cortex. Mitochondria, lipochondria, pigment granules, and electron-opaque granules are conspicuous between cortical granules and in the underlying endoplasm. Yolk platelets are restricted to the endoplasm. Cortical granules contain neutral and acid mucopolysaccharides, and possibly protein. In the mature oocyte, microvilli are withdrawn and the surface folds eliminated. Cortical granules now lie close to the plasma membrane, sometimes contacting it. Fertilization or pricking causes a wave of breakdown of cortical granules lasting 1–1½ min. Breakdown begins immediately after pricking but not until about 10–15 min after insemination, because the fertilizing sperm takes that long to penetrate the jelly and vitelline membrane. Cortical granules erupt through the surface and discharge their contents into the perivitelline space. Cortical craters left at sites of eruption soon disappear, and pseudopodial protrusions retract. By 30 min after insemination, the surface of the egg is relatively smooth.

Kemp, Norman E.; Istock, Nancy L.

1967-01-01

251

Cortical changes in growing oocytes and in fertilized or pricked eggs of Rana pipiens.  

PubMed

The folded cortex of the growing oocyte of the frog extends as microvilli into the substance of the developing vitelline membrane and, internal to the folds, possesses a layer of cortical granules. Free ribosomes, smooth-walled vesicles, coated vesicles, tubules, and electron-opaque granules are abundant in the peripheral zone of the cortex. Mitochondria, lipochondria, pigment granules, and electron-opaque granules are conspicuous between cortical granules and in the underlying endoplasm. Yolk platelets are restricted to the endoplasm. Cortical granules contain neutral and acid mucopolysaccharides, and possibly protein. In the mature oocyte, microvilli are withdrawn and the surface folds eliminated. Cortical granules now lie close to the plasma membrane, sometimes contacting it. Fertilization or pricking causes a wave of breakdown of cortical granules lasting 1-1(1/2) min. Breakdown begins immediately after pricking but not until about 10-15 min after insemination, because the fertilizing sperm takes that long to penetrate the jelly and vitelline membrane. Cortical granules erupt through the surface and discharge their contents into the perivitelline space. Cortical craters left at sites of eruption soon disappear, and pseudopodial protrusions retract. By 30 min after insemination, the surface of the egg is relatively smooth. PMID:4226727

Kemp, N E; Istock, N L

1967-07-01

252

SPHEROIDAL AND RING NUCLEOLI IN AMPHIBIAN OOCYTES  

PubMed Central

In maturing oocytes of the newt Triturus viridescens, the nucleoli undergo a series of morphological changes that are very similar to those described by Callan for the axolotl, Ambystoma mexicanum. The nucleoli first assume the form of spheroids which then become extended into ring or necklace shapes that are DNase-sensitive; in mature oocytes the nucleoli revert to a spheroidal form. Short term in vitro incorporation studies with uridine-3H on both species show that RNA synthesis occurs in a restricted, eccentric portion of the spheroidal nucleoli, thereby producing an asymmetrical pattern of labeling. In the ring forms, however, the localization of the radioactivity suggests that synthesis takes place symmetrically throughout their entire length. The changes in nucleolar morphology apparently reflect the fact that the component DNA has undergone a redistribution from a localized region in the spheroidal nucleoli to an extended circle in the rings; the patterns of uridine-3H incorporation, therefore, parallel the distribution of DNA in both the spheroidal and the ring nucleoli. Ultrastructurally, the nucleoli contain a fibrillar component that corresponds in position to that of the DNA. The typical spheroidal nucleolus consists of a fibrillar core situated eccentrically and surrounded by a hull of granular, ribonucleoprotein material. The ring nucleoli are composed of a central fibrous region that is ensheathed all around its circumference by a layer of similar granular material. This granular substance is thicker at intervals along the length of the rings, representing the "beads" of the necklaces.

Lane, Nancy J.

1967-01-01

253

Metabolic cooperation following fusion of starfish ootid and primary oocyte restores meiotic-phase-promoting activity  

PubMed Central

In the starfish Marthasterias glacialis, polyethylene glycol (PEG) homologous fused pairs consisting of two immature oocytes, blocked at the germinal vesicle stage, or two ootids, blocked at the female pronucleus stage, remain arrested at these specific stages, unless they are stimulated by the hormone 1-methyladenine. In contrast, heterologous pairs develop up to female pronucleus formation in the immature partner, indicating that maturation-promoting factor was formed under these conditions. Kinetics for this process, reconstitution of the nuclear envelopes after first polar body extrusion, and delaying effect of emetine argue for the existence of a true metabolic cooperation process requiring complementary factors present in each partner. The effect of inhibitors that penetrate the plasma membrane points to the possible involvement of endogenous proteases that may activate latent or neosynthesized maturation-promoting factor precursor and/or protein kinases. Images

Guerrier, Pierre; Neant, Isabelle

1986-01-01

254

Effects of cysteine during in vitro maturation of porcine oocytes under low oxygen tension on their subsequent in vitro fertilization and development.  

PubMed

In this study, we evaluated the effect of different concentrations of cysteine in in vitro maturation (IVM) medium during IVM under low oxygen tension (5% O(2)) of porcine oocytes on the intracellular content of glutathione (GSH) and subsequent in vitro fertilization (IVF) and development. Cumulus oocyte complexes (COCs) were collected from ovaries obtained at a local slaughterhouse, cultured in IVM medium supplemented with 0 (control), 0.05, 0.1, 0.2 or 0.6 mM cysteine for 44-46 h, fertilized in vitro and subsequently cultured for 6 days in total. The GSH content of the IVM oocytes exposed to 0, 0.05, 0.1, 0.2 or 0.6 mM cysteine increased significantly (P<0.05) as the concentration of cysteine increased (12.2, 14.0, 15.1, 16.4 and 16.4 pmol/oocyte, respectively). However, the rates of oocyte maturation, sperm penetration, male pronuclear formation, monospermy and even cleavage on Day 2 (the day of IVF was defined as Day 0) and blastocyst formation on Day 6 did not differ among the groups. Moreover, the cell numbers of blastomeres in blastocysts were uniform among the groups. These results indicate that supplementation with 0.05-0.6 mM cysteine during IVM under 5% O(2) tension significantly increased the intracellular GSH contents of IVM oocytes; however, it had no promoting effects on nuclear maturation, fertilization, male pronucleus formation and subsequent embryonic development to the blastocyst stage. PMID:19672042

Viet Linh, Nguyen; Dang-Nguyen, Thanh Quang; Nguyen, Bui Xuan; Manabe, Noboru; Nagai, Takashi

2009-08-11

255

A correlation between juvenile hormone deficiency and vitellogenic oocyte degeneration in Drosophila melanogaster  

Microsoft Academic Search

It is known from previous work that juvenile hormone (JH) is required to initiate vitellogenin uptake into maturing oocytes ofDrosophila melanogaster, but additional requirements for this hormone during oocyte maturation have not been fully understood. To determine if early vitellogenic oocytes (stages 8 and 9) require JH for continued development, these oocytes were transplanted toDrosophila female and male hosts which

Thomas G. Wilson

1982-01-01

256

THE INDUCTION OF DOMINANT LETHAL MUTATIONS IN X-IRRADIATED DROSOPHILA VIRILIS OOCYTES  

Microsoft Academic Search

Two stages of Drosophila virilis oocytes were used to study the ; induction of dominant lethal mutations: Stage 7. which is the most developed ; oocyte in newly emerged flies, and Stage 14, which is the mature oocyte and is ; present in females which have been held as virgins for five days. Stages 7 and ; 14 oocytes x

Dickerman

1963-01-01

257

THE INDUCTION OF DOMINANT LETHAL MUTATIONS IN X-IRRADIATED DROSOPHILA VIRILIS OOCYTES  

Microsoft Academic Search

To study the effect of various gases and combinations of gases on the ; induction of dominant lethal mutations in x irradiated Drosophila virilis oocytes ; two stages of oocytes were used. Females containing stage 7 oocytes were ; irradiated with 2000 r and females cortaining stage 14 oocytes were irradiated ; with 250 r. The flies were irradiated in

Dickerman

1962-01-01

258

Comparative genomic hybridization of oocytes and first polar bodies from young donors  

Microsoft Academic Search

Chromosome abnormalities are common in oocytes derived from patients undergoing IVF treatment. The proportion of oocytes displaying aneuploidy is closely related to maternal age and may exceed 60% in patients over 40 years old. However, little information currently exists concerning the incidence of such anomalies in oocytes derived from young fertile women. A total of 121 metaphase II oocytes and

E Fragouli; A Escalona; C Gutiérrez-Mateo; S Tormasi; S Alfarawati; S Sepulveda; L Noriega; J Garcia; D Wells; S Munné

2009-01-01

259

A morphologic study of unfertilized oocytes and abnormal embryos in human in vitro fertilization  

Microsoft Academic Search

The morphology of human, unfertilized oocytes and abnormal embryos cultured in vitro for 48–72 hr was examined in an attempt to learn more about oocyte maturation and reproductive failure in in vitro fertilization (IVF). About 21% of the unfertilized oocytes were totally degenerated. The majority (56%) of the remaining oocytes was arrested at the metaphase II stage. They contained coherent

Hanna Ba?akier; Robert F. Casper

1991-01-01

260

Preliminary experience with human oocyte cryopreservation using 1,2-propanediol and sucrose  

Microsoft Academic Search

Feasibility of cryopreservat ion of mature human oocytes using 1,2-propanediol and sucrose was studied initially utiliz- ing 1 and 2 day old unfertilized oocytes. Of these 285 aged oocytes 55% survived thawing, and 41% of 128 oocytes inseminated by single sperm intracytoplasmic injection (ICSI) fertilized normally. Limited embryonic development occurred in 51% of these embryos (n = 27) observed for

Michael Tucker; Graham Wright; Paula Morton; Li Shanguo; Joe Massey; Hilton Kort

1996-01-01

261

Role of oocyte quality in meiotic maturation and embryonic development.  

PubMed

The quality of oocytes plays a key role in a proper embryo development. In humans, oocytes of poor quality may be the cause of women infertility and an important obstacle in successful in vitro fertilization (IVF). The competence of oocytes depends on numerous processes taking place during the whole oogenesis, but its final steps such as oocyte maturation, seem to be of key importance. In this paper, we overview factors involved in the development of a fully functional female gamete with Xenopus laevis as a major experimental model. Modern approaches, e.g. proteomic analysis, enable the identification of novel proteins involved in oocyte development. EP45, called also Seryp or pNiXa, which belongs to the serpin (serine protease inhibitors) super-family is one of such recently analyzed proteins. This protein seems to be involved in the stimulation of meiotic maturation and embryo development. EP45 is potentially a key factor in correct oocyte development and determining the quality of oocytes. PMID:19997475

Marteil, Gaëlle; Richard-Parpaillon, Laurent; Kubiak, Jacek Z

2009-11-01

262

Regulation of redox metabolism in the mouse oocyte and embryo.  

PubMed

Energy homeostasis of the oocyte is a crucial determinant of fertility. Following ovulation, the oocyte is exposed to the unique environment of the Fallopian tube, and this is reflected in a highly specialised biochemistry. The minute amounts of tissue available have made the physiological analysis of oocyte intermediary metabolism almost impossible. We have therefore used confocal imaging of mitochondrial and cytosolic redox state under a range of conditions to explore the oxidative metabolism of intermediary substrates. It has been known for some time that the early mouse embryo metabolises external pyruvate and lactate but not glucose to produce ATP. We now show at the level of single oocytes, that supplied glucose has no effect on the redox potential of the oocyte. Pyruvate is a cytosolic oxidant but a mitochondrial reductant, while lactate is a strong cytosolic reductant via the activity of lactate dehydrogenase. Unexpectedly, lactate-derived pyruvate appears to be diverted from mitochondrial oxidation. Our approach also reveals that the level of reduced glutathione (GSH) in the oocyte is maintained by glutathione reductase, which oxidises intracellular NADPH to reduce oxidised glutathione. Surprisingly, NADPH does not seem to be supplied by the pentose phosphate pathway in the unfertilised oocyte but rather by cytosolic NADP-dependent isocitrate dehydrogenase. Remarkably, we also found that the oxidant action of pyruvate impairs development, demonstrating the fundamental importance of redox state on early development. PMID:17185319

Dumollard, Rémi; Ward, Zoe; Carroll, John; Duchen, Michael R

2006-12-21

263

Light and transmission electron microscopy of immature camelus dromedarius oocyte.  

PubMed

In order to provide a consistent system for laboratory production of embryos, the characteristics of immature camel oocyte must first be described. The objective of this study was to define ultrastructural features of immature camel oocyte. Ovaries were obtained from camels at a local abattoir, and then transported to the laboratory within 2 h. Camelus cumulus oocyte complexes (COCs) were aspirated from 2-6 mm follicles using a 22-gauge needle. Excellent and good quality COCs were selected and prepared for transmission electron microscopy study using a cavity slide. The fine structure of camel oocyte is morphologically similar to that of other mammalian oocytes. However, some minor differences exist between COC of camel and other mammalian species. Different size and shape of membrane-bound vesicles, lipid droplet, mitochondria and cortical granules were distributed throughout the ooplasm. Discrete or in association with endoplasmic reticulum, Golgi complexes were observed in the periphery of the oocytes. The majority of the oocytes were in the germinal vesicle stage. PMID:15239809

Nili, H; Mesbah, F; Kafi, M; Nasr Esfahani, M H

2004-08-01

264

Ultrastructure of in vitro oocyte maturation in buffalo (Bubalus bubalis).  

PubMed

The objective of the present study was to describe ultrastructural changes in the nucleus and cytoplasmic organelles during in vitro maturation (IVM) of buffalo cumulus-oocyte complexes (COCs). The structures were collected by ovum pick-up (OPU). Some COCs, removed from maturation medium at 0, 6, 12, 18 and 24 h, were processed for transmission electron microscopy. The average number of COCs collected by OPU/animal/session was 6.4, and 44% of them were viable. Immature oocytes had a peripherally located nucleus, Golgi complex and mitochondrial clusters, as well as a large number of coalescent lipid vacuoles. After 6 h of IVM, the oocyte nucleus morphology changed from round to a flatter shape, and the granulosa cells (GC) lost most of their contact with zona pellucida (ZP). At 12 h the first polar body was extruded and the aspect of lipid droplet changed to dark, probably denoting lipid oxidation. Cortical granules were clearly visible at 18 h of maturation, always located along the oocyte periphery. At 24 h of IVM the number of cortical granules increased. Ultrastructure studies revealed that: (1) immature oocytes have a high lipid content; (2) the perivitelline space (PS) increases during IVM; (3) Golgi complexes and mitochondrial clusters migrate to oocyte periphery during IVM; (4) 6 h of IVM are enough to lose contact between GC and ZP; (5) the oocyte lipid droplets' appearance changes between 6 and 12 h of IVM. PMID:20576206

Mondadori, Rafael Gianella; Santin, Tiago Rollemberg; Fidelis, Andrei Antonioni Guedes; Name, Khesller Patrícia Olázia; da Silva, Juliana Souza; Rumpf, Rodolfo; Báo, Sônia Nair

2010-06-25

265

7 CFR 2902.14 - Penetrating lubricants.  

Code of Federal Regulations, 2010 CFR

...2902.14 Penetrating lubricants. (a) Definition...percent and shall be based on the amount of qualifying...biobased penetrating lubricants. By that date...contains petroleum-based ingredients, re-refined... : Penetrating lubricant products...

2009-01-01

266

7 CFR 3201.14 - Penetrating lubricants.  

Code of Federal Regulations, 2013 CFR

...3201.14 Penetrating lubricants. (a) Definition...percent and shall be based on the amount of qualifying...biobased penetrating lubricants. By that date...contains petroleum-based ingredients, re-refined... ): Penetrating lubricant products...

2013-01-01

267

7 CFR 2902.14 - Penetrating lubricants.  

Code of Federal Regulations, 2010 CFR

...2902.14 Penetrating lubricants. (a) Definition...percent and shall be based on the amount of qualifying...biobased penetrating lubricants. By that date...contains petroleum-based ingredients, re-refined... : Penetrating lubricant products...

2010-01-01

268

Neonatal Chiordecone Exposure Alters Behavioral Sex Differentiation in Female Hamsters.  

National Technical Information Service (NTIS)

The present study was designed in order to determine if exposure to the weakly estrogenic pesticide Chlordecone during a critical period of behavioral sex differentiation of the brain could masculinize and defeminize the behavior of female hamsters.

L. E. Gray

1982-01-01

269

NEONATAL CHIORDECONE EXPOSURE ALTERS BEHAVIORAL SEX DIFFERENTIATION IN FEMALE HAMSTERS  

EPA Science Inventory

The present study was designed in order to determine if exposure to the weakly estrogenic pesticide Chlordecone during a critical period of behavioral sex differentiation of the brain could masculinize and defeminize the behavior of female hamsters....

270

Karyotype Analysis of Chinese Hamster Chromosomes by Flow Microfluorometry.  

National Technical Information Service (NTIS)

Chromosomes from diploid and aneuploid Chinese hamster cells were isolated at neutral pH or following fixation in 50% acetic acid, stained with ethidium bromide, and analyzed by flow microfluorometry (FMF). In some experiments, the chromosomes were partia...

L. L. Deaven E. Stubblefield J. H. Jett

1976-01-01

271

Inducibility of glutathione S-transferases in hamsters.  

PubMed

The effects of 3-methylcholanthrene (3-MC), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), phenobarbital, trans-stilbene oxide (TSO), pregnenolone-16 alpha-carbonitrile (PCN), dexamethasone, ethanol, isoniazid and butylated hydroxyanisole (BHA) on hepatic glutathione S-transferase (GST) activities toward six substrates were determined in hamsters. TCDD and 3-MC, which are comparatively poor inducers of GSTs in rats, were most effective in enhancing GST activities in hamster liver. In contrast, TSO, BHA and phenobarbital, which are very effective inducers of hepatic GSTs in rats and mice, were ineffective or poor inducers of GSTs in hamster liver. While dexamethasone increased some GST activities, treatments with PCN, ethanol and isoniazid were without effect. The findings indicate that not only the control activity but also the inducibility of hepatic GSTs are different in hamsters from those in other species. PMID:2920375

Gregus, Z; Madhu, C; Klaassen, C D

1989-02-01

272

Selective carboxyl methylation of structurally altered calmodulins in Xenopus oocytes  

SciTech Connect

The eucaryotic protein carboxyl methyltransferase specifically modifies atypical D-aspartyl and L-isoaspartyl residues which are generated spontaneously as proteins age. The selectivity of the enzyme for altered proteins in intact cells was explored by co-injecting Xenopus laevis oocytes with S-adenosyl-L-(methyl-3H)methionine and structurally altered calmodulins generated during a 14-day preincubation in vitro. Control experiments indicated that the oocyte protein carboxyl methyltransferase was not saturated with endogenous substrates, since protein carboxyl methylation rates could be stimulated up to 8-fold by increasing concentrations of injected calmodulin. The oocyte protein carboxyl methyltransferase showed strong selectivities for bovine brain and bacterially synthesized calmodulins which had been preincubated in the presence of 1 mM EDTA relative to calmodulins which had been preincubated with 1 mM CaCl2. Radioactive methyl groups were incorporated into base-stable linkages with recombinant calmodulin as well as into carboxyl methyl esters following its microinjection into oocytes. This base-stable radioactivity most likely represents the trimethylation of lysine 115, a highly conserved post-translational modification which is present in bovine and Xenopus but not in bacterially synthesized calmodulin. Endogenous oocyte calmodulin incorporates radioactivity into both carboxyl methyl esters and into base-stable linkages following microinjection of oocytes with S-adenosyl-(methyl-3H)methionine alone. The rate of oocyte calmodulin carboxyl methylation in injected oocytes is calculated to be similar to that of lysine 115 trimethylation, suggesting that the rate of calmodulin carboxyl methylation is similar to that of calmodulin synthesis. At steady state, oocyte calmodulin contains approximately 0.0002 esters/mol of protein, which turn over rapidly.

Desrosiers, R.R.; Romanik, E.A.; O'Connor, C.M. (Worcester Foundation for Experimental Biology, Shrewsbury, MA (USA))

1990-12-05

273

Telomere lengths in human pronuclei, oocytes and spermatozoa.  

PubMed

Telomeres are chromosome ends that control functions related to cell division. Short telomeres are proposed to underlie infertility, female reproductive ageing and abnormal embryogenesis, but there is little direct evidence on telomere length in gametes and embryos. The aim of this study was to measure telomere lengths in individual human oocytes, spermatozoa, male and female pronuclei, in order to compare parental contributions to telomere lengths in the human zygote. Quantitative fluorescence in situ hybridization was used to measure average telomere length in pronuclei of oocytes fertilized for research using a known fertile sperm sample. Pronuclei derived from male and female gametes were distinguished by 5-methylcytosine staining. Results were compared with those for unfertilized mature and immature oocytes and individual spermatozoa decondensed in vitro. Fifty unselected men and one sperm donor provided semen samples and 32 women donated oocytes surplus to IVF treatment. Telomeres in mature oocytes and female pronuclei were significantly longer than those in individual spermatozoa and male pronuclei (P < 0.0001). Telomeres were longer in immature oocytes than in mature oocytes (P < 0.04). Sperm telomere length increased with male age (P < 0.05). Neither sperm nor oocyte telomere lengths were significantly associated with clinical parameters or outcome of treatment. In conclusion, telomere length measurements directly comparing human pronuclei under identical conditions show that male-derived telomeres are shorter on average than female-derived telomeres at fertilization. We propose that from this starting point, telomere lengths are probably modified by recombination events in the oocyte until telomerase increases at the blastocyst stage. Our findings do not support the use of gamete telomere lengths as a fertility diagnostic tool. PMID:23519357

Turner, S; Hartshorne, G M

2013-03-20

274

Effects of follicle size and oocyte maturation conditions on maternal messenger RNA regulation and gene expression in rhesus monkey oocytes and embryos.  

PubMed

The relationship between alterations in gene expression and differences in developmental potential in primate oocytes and embryos was examined. Oocytes from 3 sources were used for these studies: 1) in vivo-matured oocytes from monkeys stimulated with FSH and hCG, 2) in vitro-matured oocytes from large follicles of monkeys primed with FSH, and 3) in vitro-matured oocytes from small follicles from nonstimulated (NS) monkeys. Following in vitro fertilization, embryos from these oocytes displayed high, moderate, and low developmental competence, respectively. Oocytes from NS females displayed aberrant accumulation of a number of maternal mRNAs, followed by precocious loss of many maternal mRNAs by the 2-cell stage. Embryos from NS oocytes displayed alterations in expression of key transcription factors after the 8-cell stage. Oocytes and embryos from FSH-stimulated females also displayed alterations in gene expression relative to hCG-stimulated females, but these alterations were much less severe than those observed for NS oocytes and embryos. Our data are consistent with the hypothesis that continued development and maturation of the oocyte within the ovarian follicle in vivo facilitates the production of oocytes of the highest developmental potential, and that in vitro conditions may not support this process as effectively due to differences in the extracellular milieu. These observations are relevant to understanding the role of the in vivo environment on oocyte maturation, and the potential effects of in vitro maturation on human assisted reproduction methods. PMID:15590902

Zheng, Ping; Patel, Bela; McMenamin, Malgorzata; Moran, Elizabeth; Paprocki, Ann Marie; Kihara, Maki; Schramm, R Dee; Latham, Keith E

2004-12-08

275

Lesions of the Thalamic Intergeniculate Leaflet Alter Hamster Circadian Rhythms  

Microsoft Academic Search

We have investigated the effects of destruction of the geniculo-hypothalamic tract (GHT) on the circadian system of golden hamsters. In the first experiment, intact hamsters were housed in constant darkness, and phase shifts in running-wheel activity rhythms were assessed following 15-min light pulses administered at circadian time (CT) 12 (defined as the beginning of activity), CT 14, CT 18, and

Mary E. Harrington; Benjamin Rusak

1986-01-01

276

Testosterone and chemosensory detection in male Syrian hamster  

Microsoft Academic Search

Gonadal steroids stimulate both sexual motivation and performance. However, steroid facilitation of appetitive sexual behavior is poorly understood. The present study determined if castration impairs chemosensory detection in male hamsters. Chemosensory cues are the principal sensory modality to initiate mating in this species. We compared LiCl-induced conditioned taste avoidance to female hamster vaginal secretion (FHVS) in gonad-intact and castrated males.

Kelly D. Peters; Steve M. Hom; Ruth I. Wood

2004-01-01

277

Blood gas analyses of hibernating hamsters and dormice  

Microsoft Academic Search

Blood gases were measured in hibernating and hypothermic animals as a biological model of clinical hypothermia. Blood gas analyses from hamsters and dormice were carried out with the aid of permanent arterial catheters during normothermia and hibernation. In golden hamster pH increased from 7.30 to 7.46 during hibernation andPaCO2 decreased from 59.7 to 40.5 mm Hg. In dormice pH increased

G. Kreienbühl; J. Strittmatter; E. Ayim

1976-01-01

278

Airborne Penetration of Radioactive Clouds.  

National Technical Information Service (NTIS)

This report evaluates the threat to aircrew members when their aircraft approaches and subsequently penetrates a descending radioactive cloud generated by a nuclear weapon surface burst. The re-development of Hickman's program consists of a remodeling of ...

T. R. Kling

1983-01-01

279

Experimental investigation of wavelength dependence of penetration depth and imaging contrast for ultrahigh-resolution optical coherence tomography  

NASA Astrophysics Data System (ADS)

Optical coherence tomography (OCT) is a non invasive optical imaging technology for micron-scale cross-sectional imaging of biological tissue and materials. Although OCT has many advantages in medical equipments, low penetration depth is a serious limitation for other applications. To realize the ultrahigh resolution and the high penetration depth at the same time, it is effective to choose the proper wavelength to maximize the light penetration and enhance the image contrast at deeper depths. Recently, we have demonstrated ultrahigh resolution and high penetration depth OCT by use of all-fiber based Gaussian shaped supercontinuum source at 1.7 ?m center wavelength. Gaussian-like supercontinuum with 360 nm bandwidth at center wavelength of 1.7 ?m was generated by ultrashort pulse Er doped fiber laser based system. In this paper, using 0.8 ?m and 1.3 ?m SC sources in addition to the 1.7 ?m SC source, we have investigated the wavelength dependence of ultrahigh resolution OCT in terms of penetration depth. Longitudinal resolutions at each wavelength region are almost 4.6 ?m in air. The obtained sensitivity was 95 dB for all wavelength regions. We confirmed the difference of imaging contrast and penetration depth with hamster's cheek pouch and so on. As the wavelength was increased, the magnitude of penetration depth was increased for these samples.

Ishida, S.; Nishizawa, N.; Itoh, K.

2011-02-01

280

Regulation of hamster splenocyte reactivity to concanavalin A during pregnancy  

SciTech Connect

The survival to term of mammalian fetuses regardless of their expression of paternal or embryonic developmental antigens suggests that some alteration in the immune capabilities of a female occur during pregnancy. The immunocompetence of female Syrian golden hamsters during pregnancy was investigated with respect to the blastogenic response of spleen cells to the T-cell mitogen concanavalin A (Con A). The blastogenic response of spleen cells from pregnant hamsters during mid- or late gestation is 10% of that observed for spleen cells from age-matched, virgin female animals. The spleen cells from pregnant hamsters are not capable of suppressing the proliferative response of spleen cells from virgin females to Con A. However, the serum from pregnant hamsters, in comparison with serum from virgin female animals, is capable of reducing this mitogenic response. Extensive washing of the splenocytes from pregnant hamsters does reduce the degree of suppression. These results suggest that the hamster is an excellent animal model for the investigation of the mechanism(s) of immune regulation that operate during pregnancy.

Weppner, W.A.; Coggin, J.H. Jr.

1980-08-15

281

Weather entrainment and multispectral diel activity rhythm of desert hamsters.  

PubMed

The circadian rhythm of animals is an adaptation to predictable variation in environmental conditions. Multiple internal oscillators may allow animals to cope with environmental oscillations in different frequencies. Heat stress and dramatic differences between night and day temperatures are the main selective pressures of the diel activity of desert mammals, particularly small-sized rodents. We tested the hypotheses that the diel activities of desert hamsters (Phodopus roborovskii) would be entrained by ambient humidity and temperature. We predicted that increases in night temperature and humidity would improve the propensity to perform activities of the hamster. We observed hourly activities of desert hamsters under semi natural conditions for 24 consecutive hours, with seven replicates in 7 different days. We fit generalized linear mixed models to observed proportions of active hamsters, temperatures, and relative humidity. Observed diel activities of desert hamsters consisted of three harmonic oscillations in the periodicities of 24h, 12h, and 6h, respectively. Furthermore, probabilities to perform activities were positively related to night temperature and humidity. Therefore, the diel activities of desert hamsters are synchronized by atmospheric humidity, temperatures, and environmental cues of ultradian fluctuations. PMID:23810901

Wan, Xinrong; Zhang, Xinjie; Huo, Yingjun; Wang, Guiming

2013-06-25

282

Regulation of tonic gonadotropin release in prepubertal female hamsters  

SciTech Connect

Basal serum gonadotropin levels were monitored weekly in female hamsters from birth to 10 weeks of age. Hamsters raised on three different photoperiods presented uniform pre- and postpubertal patterns of serum LH and FSH, suggesting that gonadotropin release in the young hamster occurs independently of ambient photoperiod. In all groups, serum LH levels increased gradually in animals up to 4 weeks of age, after which levels plateaued at 50--100 ng/ml. Serum FSH was markedly elevated in 2- and 3-week-old hamsters (800--1200 ng/ml), but remained at 200--400 ng/ml in all other groups. We next examined the change in the responsiveness of the pituitary to exogenous gonadotropin-releasing hormone (GnRH) challenge. Female hamsters 2 days of age failed to respond to any dose (0.025--1000 ng) of GnRH, while 10-day old females responded in typical dose-dependent fashion. GnRH-stimulated LH release first occurred in 6-day-old hamsters and was maximal by day 9, whereas FSH release first occurred on day 8 and was maximal by day 9. The prepubertal pattern of gonadotropin release can, in part, be explained on the basis of the development of pituitary GnRH sensitivity, which occurs independently of photoperiod.

Smith, S.G.; Matt, K.S.; Prestowitz, W.F.; Stetson, M.H.

1982-04-01

283

Enhancement of ocular drug penetration.  

PubMed

Although new drugs have recently been developed within the field of ophthalmology, the eye's various defense mechanisms make it difficult to achieve an effective concentration of these drugs within the eye. Drugs administered systemically have poor access to the inside of the eye because of the blood-aqueous and blood-retinal barriers. And although topical instillation of drugs is very popular in ophthalmology, topically applied drugs are rapidly eliminated from the precorneal area. In addition, the cornea, considered a major pathway for ocular penetration of topically applied drugs, is an effective barrier to drug penetration, since the corneal epithelium has annular tight junctions (zonula occludens), which completely surround and effectively seal the superficial epithelial cells. Various drug-delivery systems have been developed to increase the topical bioavailability of ophthalmic drugs by enhancement of the ocular drug penetration. The first approach is to modify the physicochemical property of drugs by chemical and pharmaceutical means. An optimum promoiety can be covalently bound to a drug molecule to obtain a prodrug that can chemically or enzymatically be converted to the active parent drug, either within the cornea or after the corneal penetration. Along these same lines, the transient formation of a lipophilic ion pair by ionic bonding is also useful for improving ocular drug penetration. The second approach is to modify the integrity of the corneal epithelium transiently by coadministration of an amphiphilic substance or by chelating agents that act as drug-penetration enhancers. The third approach modifies the integrity of the corneal epithelium transiently by physical techniques including iontophoresis and phonophoresis. This paper reviews the absorption behavior and ocular membranes penetration of topically applied drugs, and the various approaches for enhancement of ocular drug penetration in the eye. PMID:10099899

Sasaki, H; Yamamura, K; Mukai, T; Nishida, K; Nakamura, J; Nakashima, M; Ichikawa, M

1999-01-01

284

High-throughput electrophysiology with Xenopus oocytes  

PubMed Central

Voltage-clamp techniques are typically used to study the plasma membrane proteins, such as ion channels and transporters that control bioelectrical signals. Many of these proteins have been cloned and can now be studied as potential targets for drug development. The two approaches most commonly used for heterologous expression of cloned ion channels and transporters involve either transfection of the genes into small cells grown in tissue culture or the injection of the genetic material into larger cells. The standard large cells used for the expression of cloned cDNA or synthetic RNA are the egg progenitor cells (oocytes) of the African frog, Xenopus laevis. Until recently, cellular electrophysiology was performed manually, one cell at a time by a single operator. However, methods of high-throughput electrophysiology have been developed which are automated and permit data acquisition and analysis from multiple cells in parallel. These methods are breaking a bottleneck in drug discovery, useful in some cases for primary screening as well as for thorough characterization of new drugs. Increasing throughput of high-quality functional data greatly augments the efficiency of academic research and pharmaceutical drug development. Some examples of studies that benefit most from high-throughput electrophysiology include pharmaceutical screening of targeted compound libraries, secondary screening of identified compounds for subtype selectivity, screening mutants of ligand-gated channels for changes in receptor function, scanning mutagenesis of protein segments, and mutant-cycle analysis. We describe here the main features and potential applications of OpusXpress, an efficient commercially available system for automated recording from Xenopus oocytes. We show some types of data that have been gathered by this system and review realized and potential applications.

Papke, Roger L.; Smith-Maxwell, Cathy

2010-01-01

285

Mouse oocytes enable LH-induced maturation of the cumulus-oocyte complex via promoting EGF receptor-dependent signaling.  

PubMed

LH triggers the maturation of the cumulus-oocyte complex (COC), which is followed by ovulation. These ovarian follicular responses to LH are mediated by epidermal growth factor (EGF)-like growth factors produced by granulosa cells and require the participation of oocyte-derived paracrine factors. However, it is not clear how oocytes coordinate with the EGF receptor (EGFR) signaling to achieve COC maturation. The aim of the present study was to test the hypothesis that oocytes promote the expression of EGFR by cumulus cells, thus enabling them to respond to the LH-induced EGF-like peptides. Egfr mRNA and protein expression were dramatically reduced in cumulus cells of mutant mice deficient in the production of the oocyte-derived paracrine factors growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15). Moreover, microsurgical removal of oocytes from wild-type COCs dramatically reduced expression of Egfr mRNA and protein, and these levels were restored by either coculture with oocytes or treatment with recombinant GDF9 or GDF9 plus recombinant BMP15. Blocking Sma- and Mad-related protein (SMAD)2/3 phosphorylation in vitro inhibited Egfr expression in wild-type COCs and in GDF9-treated wild-type cumulus cells, and conditional deletion of Smad2 and Smad3 genes in granulosa cells in vivo resulted in the reduction of Egfr mRNA in cumulus cells. These results indicate that oocytes promote expression of Egfr in cumulus cells, and a SMAD2/3-dependent pathway is involved in this process. At least two oocyte-derived growth factors, GDF9 and BMP15, are required for EGFR expression by cumulus cells. PMID:20382892

Su, You-Qiang; Sugiura, Koji; Li, Qinglei; Wigglesworth, Karen; Matzuk, Martin M; Eppig, John J

2010-04-09

286

Mouse Oocytes Enable LH-Induced Maturation of the Cumulus-Oocyte Complex via Promoting EGF Receptor-Dependent Signaling  

PubMed Central

LH triggers the maturation of the cumulus-oocyte complex (COC), which is followed by ovulation. These ovarian follicular responses to LH are mediated by epidermal growth factor (EGF)-like growth factors produced by granulosa cells and require the participation of oocyte-derived paracrine factors. However, it is not clear how oocytes coordinate with the EGF receptor (EGFR) signaling to achieve COC maturation. The aim of the present study was to test the hypothesis that oocytes promote the expression of EGFR by cumulus cells, thus enabling them to respond to the LH-induced EGF-like peptides. Egfr mRNA and protein expression were dramatically reduced in cumulus cells of mutant mice deficient in the production of the oocyte-derived paracrine factors growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15). Moreover, microsurgical removal of oocytes from wild-type COCs dramatically reduced expression of Egfr mRNA and protein, and these levels were restored by either coculture with oocytes or treatment with recombinant GDF9 or GDF9 plus recombinant BMP15. Blocking Sma- and Mad-related protein (SMAD)2/3 phosphorylation in vitro inhibited Egfr expression in wild-type COCs and in GDF9-treated wild-type cumulus cells, and conditional deletion of Smad2 and Smad3 genes in granulosa cells in vivo resulted in the reduction of Egfr mRNA in cumulus cells. These results indicate that oocytes promote expression of Egfr in cumulus cells, and a SMAD2/3-dependent pathway is involved in this process. At least two oocyte-derived growth factors, GDF9 and BMP15, are required for EGFR expression by cumulus cells.

Su, You-Qiang; Sugiura, Koji; Li, Qinglei; Wigglesworth, Karen; Matzuk, Martin M.; Eppig, John J.

2010-01-01

287

The dormant and the fully competent oocyte: comparing the transcriptome of human oocytes from primordial follicles and in metaphase II.  

PubMed

Oocytes become enclosed in primordial follicles during fetal life and remain dormant there until activation followed by growth and meiotic resumption. Current knowledge about the molecular pathways involved in oogenesis is incomplete. This study identifies the specific transcriptome of the human oocyte in the quiescent state and at the pinnacle of maturity at ovulation. In silico bioinformatic comparisons were made between the transcriptome of human oocytes from dormant primordial follicles and that of human metaphase II (MII) oocytes and granulosa cells and unique gene expression profiles were identified as well as functional and pathway enrichments associated with the oocytes from the two developmental hallmarks. A total of 729 genes were highly enriched in oocytes from primodial follicles and 1456 genes were highly enriched in MII oocytes (>10-fold, P < 0.001) representing functional categories such as cell cycle regulation, DNA protection and epigenetics, with representative genes validated by qPCR analysis. Dominating canonical pathways in the oocytes from primordial follicles were androgen, estrogen receptor, glucocorticoid receptor and PI3K/AKT signaling (P < 0.001). In the MII, mitotic roles of polo-like kinases, estrogen receptor, JAK/Stat signaling (P < 0.001) and the ERK/MAPK (P < 0.01) signaling were enriched. Some of the highly differentially expressed genes were completely new in human reproduction (CDR1, TLC1A, UHRF2) while other genes [ABO, FOLR1 (folate receptor), CHRNA3 (nicotine receptor)] may relate to clinical observations as diverse as premature ovarian failure, folic acid deficiency and smoking affecting female fertility. The in silico analysis identified novel reproduction-associated genes and highlighted molecular mechanisms and pathways associated with the unique functions of the human oocyte in its two extremes during folliculogenesis. The data provides a fundamental basis for future functional studies in regulation of human oogenesis. PMID:23598597

Grøndahl, Marie Louise; Borup, Rehannah; Vikeså, Jonas; Ernst, Erik; Andersen, Claus Yding; Lykke-Hartmann, Karin

2013-04-18

288

Demonstration of Survivable Space Penetrator  

NASA Astrophysics Data System (ADS)

This work was performed in support of MoonLITE which is a proposed UK space mission to the moon. The basic premise is to deploy 4 instrumented penetrators, one each on the near-side, far-side and at the poles of the moon, with an impact velocity of approximately 300m/s. The primary science aims are to set up a passive seismometer network, investigate the presence of water and volatiles and determine thermal gradients in the lunar soil (i.e. regolith). A key requirement is that the penetrator shell survives the impact together with the instrument payload and supporting subsystems. The material chosen for the penetrator shell was 7075 aluminum alloy, which is a good compromise between high compressive strength and low mass. The baseline penetrator design was evaluated and refined using the DYNA3D hydrocode to determine the survivability of the penetrator in sand at an impact velocity of 300m/s and an attack angle of 8 degrees. The simulations predicted that the penetrator design would survive this severe impact condition which was confirmed by experiments on the Pendine rocket test track.

Church, P.; Huntington-Thresher, W.; Penny, N.; Bruce, A.; Smith, A.; Gowan, R.

2009-06-01

289

[Fertilizing capacity of the ejaculate of nutria (Myocastor coypus) after the removal of the seminal vesicles as evaluated by the penetration test and natural mating].  

PubMed

The fertility of male coypu sperm following seminal vesicle extirpation was investigated using the penetration test into the egg of Syrian golden hamster (Mesocricetus auratus). Ejaculates were obtained from five males by means of electro-ejaculation under halothane narcosis. The results of the zona-free hamster eggs (ZFHE) penetration test showed that the ejaculates of all the surgically treated coypu males were fertile and that ZFHE value fluctuated from 54 to 76.6%. The results obtained in experiments with natural mating revealed that the extirpation of male coypu seminal vesicles did not affect their fertility. In total 47 foetuses were found post mortem in ten coypu females covered by surgically treated males, which on average represented 4.7 foetuses per female. PMID:2678717

Jakubicka, I; Barta, M; Babusík, P

1989-07-01

290

Unrestricted Diffusion of Exogenous and Endogenous PIP 2 in Baby Hamster Kidney and Chinese Hamster Ovary Cell Plasmalemma  

Microsoft Academic Search

We used two approaches to characterize the lateral mobility of phosphatidylinositol 4,5-bisphosphate (PIP2) in the plasmalemma of baby hamster kidney and Chinese hamster ovary fibroblasts. First, nitrobenzoxadiazole-labeled C6-phosphatidylcholine\\u000a and C16-PIP2 were incorporated into plasma membrane “lawns” (?20 × 30 ?m) from these cells and into the outer monolayer of intact cells.\\u000a Diffusion coefficients determined by fluorescence recovery after photobleaching were similar for

Alp Yaradanakul; Donald W. Hilgemann

2007-01-01

291

Hypotonicity activates a native chloride current in Xenopus oocytes  

PubMed Central

Xenopus oocytes are frequently utilized for in vivo expression of cellular proteins, especially ion channel proteins. A thorough understanding of the endogenous conductances and their regulation is paramount for proper characterization of expressed channel proteins. Here we detail a novel chloride current (ICl.swell) responsive to hypotonicity in Xenopus oocytes using the two-electrode voltage clamp technique. Reducing the extracellular osmolarity by 50% elicited a calcium-independent chloride current having an anion conductivity sequence identical with swelling-induced chloride currents observed in epithelial cells. The hypotonicity-activated current was blocked by chloride channel blockers, trivalent lanthanides, and nucleotides. G- protein, cAMP-PKA, and arachidonic acid signaling cascades were not involved in ICl.swell activation. ICl.swell is distinct from both stretch-activated nonselective cation channels and the calcium- activated chloride current in oocytes and may play a critical role in volume regulation in Xenopus oocytes.

1994-01-01

292

Cytoplasmic glutathione regulated by cumulus cells during porcine oocyte maturation affects fertilization and embryonic development in vitro  

Microsoft Academic Search

It is generally accepted that cumulus cells support the nuclear maturation of mammalian oocytes. In the present study, we examined relationships between the cytoplasmic glutathione (GSH) content of porcine oocytes, and oocyte nuclear maturation, fertilization or subsequent embryonic development. Cumulus-oocyte complexes (COCs; control group) and oocytes denuded of cumulus cells after collection (DO 0h group) were cultured for 24h with

N. Maedomari; K. Kikuchi; M. Ozawa; J. Noguchi; H. Kaneko; K. Ohnuma; M. Nakai; M. Shino; T. Nagai; N. Kashiwazaki

2007-01-01

293

Human oocyte and ovarian tissue cryopreservation and its application  

PubMed Central

Purpose To review the recent progress in human oocyte and ovarian tissue cryopreservation, and in the application of these two technologies for preserving female fertility of patients who are undergoing cancer treatment. Design The literature on human oocyte and ovarian tissue freezing was searched with PubMed. The scientific background, current developments and potential future applications of these two methods were reviewed. Results Chemotherapy and/or radiotherapy can induce premature ovarian failure in most of female cancer patients. Consequently, there has been a greater need for options to preserve the reproductive potential of these individuals. However, options are somewhat limited currently, particularly following aggressive chemotherapy and/or radiotherapy treatment protocols. In recent years, there have been considerable advances in the cryopreservation of human oocytes and ovarian tissue. For women facing upcoming cancer therapies, cryopreservation of ovarian tissue and oocytes is a technology that holds promise for banking reproductive potential for the future. Recent laboratory modifications have resulted in improved oocyte survival, oocyte fertilization, and pregnancy rates from frozen–thawed oocytes in IVF. This suggests potential for clinical application. Conclusions In the case of patients who are facing infertility due to cancer therapy, oocyte cryopreservation may be one of the few options available. Ovarian tissue cryopreservation can only be recommended as an experimental protocol in carefully selected patients. In ovarian tissue transplantation, more research is needed in order to enhance the revascularization process with the goal of reducing the follicular loss that takes place after tissue grafting. These technologies are still investigational, although tremendous progress has been made. The availability of such treatment will potentially lead to its demand not only from patients with cancer but also from healthy women who chose to postpone childbearing until later in life and therefore wish to retain their fertility.

Del Valle, Alfonso

2008-01-01

294

Zinc availability regulates exit from meiosis in maturing mammalian oocytes  

Microsoft Academic Search

Cellular metal ion fluxes are known in alkali and alkaline earth metals but are not well documented in transition metals. Here we describe major changes in the zinc physiology of the mammalian oocyte as it matures and initiates embryonic development. Single-cell elemental analysis of mouse oocytes by synchrotron-based X-ray fluorescence microscopy (XFM) revealed a 50% increase in total zinc content

Alison M Kim; Stefan Vogt; Thomas V O'Halloran; Teresa K Woodruff

2010-01-01

295

PROTEIN SYNTHESIS AND UPTAKE BY ISOLATED CECROPIA OOCYTES  

Microsoft Academic Search

SUMMARY A procedure has been developed for separating the oocytes and follicular epithelium-nurse cell complexes making up the vitellogenic ovarian follicle of the Cecropia moth. Both com- ponents remained viable during short-term in vitro incubation in female blood. Isolated epithelial cells were found by autoradiography to incorporate tritiated amino acids and to secrete a fixable, non-dialysable labelled material. Isolated oocytes

LUCY M. ANDERSON

296

Chromatin organization and meiotic non-disjunction in mouse oocytes  

Microsoft Academic Search

Two forms of oocytes termed SN (Surrounded Nucleolus) and NSN (Non Surrounded Nucleolus) differing for the spatial distribution\\u000a of nuclear and nucleolar-associated chromatin have been described within the antral compartment of the ovary of a number of\\u000a mammals. The biological significance of these two kinds of oocytes is as yet not completely clear. In previous studies we\\u000a have shown that

Maurizio Zuccotti; Michele Boiani; Silvia Garagna; Carlo Alberto Redi

1998-01-01

297

Transvaginal collection and ultrastructure of Llama ( Lama glama ) oocytes  

Microsoft Academic Search

Ultrasound-guided transvaginal follicle aspiration has been described as a noninvasive and repeatable procedure for oocyte collection in several species, but its use has not been described for any of the members of the family, Camelidae. A study was designed to determine the feasibility of an ultrasound-guided transvaginal approach for oocyte collection in llamas. Fifteen non-pregnant, adult female llamas (10 non-stimulated

G. M. Brogliatti; A. T. Palasz; H. Rodriguez-Martinez; R. J. Mapletoft; G. P. Adams

2000-01-01

298

Oocyte ultrastructure in bovine primordial to early tertiary follicles  

Microsoft Academic Search

The aim of the present study was to describe in detail the changes occurring in the cytoplasmic ultrastructure of the bovine\\u000a oocyte from the onset of growth in the primordial follicle until the completion of growth in the tertiary follicle. Bovine\\u000a oocytes from primordial, primary, secondary and early to mid-antral follicles were processed and analysed by light and transmission\\u000a electron

T. Fair; S. C. J. Hulshof; P. Hyttel; T. Greve; M. Boland

1997-01-01

299

Pregnancy after immature oocyte donation and intracytoplasmic sperm injection  

Microsoft Academic Search

Objective: To report a case of pregnancy from in vitro-matured primary oocytes fertilized by ICSI. The pregnancy occured in a woman who was in an oocyte donation program; the woman's husband had normal sperm parameters.Design: Case report.Setting: Private general hospital affiliated with a university hospital.Patient(s): A recipient with premature ovarian failure, a recipient's husband with normal sperm, and a pregnant

Jiann-Loung Hwang; Yu-Hung Lin; Yieh-Loong Tsai

1997-01-01

300

In Vivo Induction of Oocyte Maturation and Ovulation in Zebrafish  

PubMed Central

The maturation of fish oocytes is a well-characterized system induced by progestins via non-genomic actions. In a previous study, we demonstrated that diethylstilbestrol (DES), a non-steroidal estrogen, induces fish oocyte maturation via the membrane progestin receptor (mPR). Here, we attempted to evaluate the effect of DES as an environmental endocrine disrupting chemical (EDC) upon fish oocyte maturation using live zebrafish. DES triggered oocyte maturation within several hours in vivo when administrated directly into the surrounding water. The natural teleost maturation-inducing hormone, 17alpha, 20beta-dihydroxy-4-pregnen-3-one (17,20beta-DHP) also induced oocyte maturation in vivo. Steroids such as testosterone, progesterone or 17alpha-hydroxyprogesterone were also effective in vivo. Further studies indicated that externally applied 17,20beta-DHP even induced ovulation. In contrast to 17,20beta -DHP, DES induced maturation but not ovulation. Theoretically this assay system provides a means to distinguish pathways involved in the induction of ovulation, which are known to be induced by genomic actions from the pathway normally involved in the induction of oocyte maturation, a typical non-genomic action-dependent pathway. In summary, we have demonstrated the effect of EDCs on fish oocyte maturation in vivo. To address the effects, we have explored a conceptually new approach to distinguish between the genomic and non-genomic actions induced by steroids. The assay can be applied to screens of progestin-like effects upon oocyte maturation and ovulation for small molecules of pharmacological agents or EDCs.

Tokumoto, Toshinobu; Yamaguchi, Toshiya; Ii, Sanae; Tokumoto, Mika

2011-01-01

301

Developmental pattern of the secretion of cumulus expansion-enabling factor by mouse oocytes and the role of oocytes in promoting granulosa cell differentiation  

Microsoft Academic Search

The expansion, or mucification, of the mouse cumulus oophorus in vitro requires the presence of an enabling factor secreted by the oocyte as well as stimulation with follicle-stimulating hormone (FSH). This study focuses on (1) the ability of mouse oocytes to secrete the enabling factor at various times during oocyte growth and maturation, (2) the temporal relationships between the development

B C Vanderhyden; P J Caron; R Buccione; J J Eppig

1990-01-01

302

Selective degradation of transcripts during meiotic maturation of mouse oocytes  

PubMed Central

There is massive destruction of transcripts during the maturation of mouse oocytes. The objective of this project was to identify and characterize the transcripts that are degraded versus those that are stable during the transcriptionally silent germinal vesicle (GV)-stage to metaphase II (MII)-stage transition using a microarray approach. A system for oocyte transcript amplification using both internal and 3’-poly(A) priming was utilized to minimize the impact of complex variations in transcript polyadenylation prevalent during this transition. Transcripts were identified and quantified using the Affymetrix Mouse Genome 430 v2.0 GeneChip. The significantly changed and stable transcripts were analyzed using Ingenuity Pathways Analysis and GenMAPP/MAPPFinder to characterize the biological themes underlying global changes in oocyte transcripts during maturation. It was concluded that the destruction of transcripts during the GV to MII transition is a selective rather than promiscuous process in mouse oocytes. In general, transcripts involved in processes that are associated with meiotic arrest at the GV-stage and the progression of oocyte maturation, such as oxidative phosphorylation, energy production, and protein synthesis and metabolism, were dramatically degraded. In contrast, transcripts encoding participants in signaling pathways essential for maintaining the unique characteristics of the MII-arrested oocyte, such as those involved in protein kinase pathways, were the most prominent among the stable transcripts.

Su, You-Qiang; Sugiura, Koji; Woo, Yong; Wigglesworth, Karen; Kamdar, Sonya; Affourtit, Jason; Eppig, John J.

2007-01-01

303

Developmentally acquired PKA localisation in mouse oocytes and embryos.  

PubMed

Localisation of Protein Kinase A (PKA) by A-Kinase Anchoring Proteins (AKAPs) is known to coordinate localised signalling complexes that target cAMP-mediated signalling to specific cellular sub-domains. The cAMP PKA signalling pathway is implicated in both meiotic arrest and meiotic resumption, thus spatio-temporal changes in PKA localisation during development may determine the oocytes response to changes in cAMP. In this study we aim to establish whether changes in PKA localisation occur during oocyte and early embryo development. Using fluorescently-labelled PKA constructs we show that in meiotically incompetent oocytes PKA is distributed throughout the cytoplasm and shows no punctuate localisation. As meiotic competence is acquired, PKA associates with mitochondria. Immature germinal vesicle (GV) stage oocytes show an aggregation of PKA around the GV and PKA remains co-localised with mitochondria throughout oocyte maturation. After fertilisation, the punctuate, mitochondrial distribution was lost, such that by the 2-cell stage there was no evidence of PKA localisation. RT-PCR and Western blotting revealed two candidate AKAPs that are known to be targeted to mitochondria, AKAP1 and D-AKAP2. In summary these data show a dynamic regulation of PKA localisation during oocyte and early embryo development. PMID:18367160

Webb, Rachel J; Tinworth, Lorna; Thomas, Geraint M H; Zaccolo, Manuela; Carroll, John

2008-02-14

304

The CDC14A phosphatase regulates oocyte maturation in mouse  

PubMed Central

The final steps of oogenesis occur during oocyte maturation that generates fertilization-competent haploid eggs capable of supporting embryonic development. Cyclin-dependent kinase 1 (CDK1) drives oocyte maturation and its activity and actions on substrates are tightly regulated. CDC14 is a dual-specificity phosphatase that reduces CDK1 activity and reverses the actions of CDK1 during mitosis. In budding yeast, Cdc14 is essential for meiosis, but it is not known whether its mammalian homolog CDC14A is required for meiosis in females. Here, we report that CDC14A is concentrated in the nucleus of meiotically incompetent mouse oocytes but is dispersed throughout meiotically competent oocytes. During meiotic progression CDC14A has no specific sub-cellular localization except between metaphase of meiosis I (Met I) and metaphase of meiosis II (Met II) when it co-localizes with the central portion of the meiotic spindle. Overexpression of CDC14A generally delays meiotic progression after resumption of meiosis whereas microinjection of oocytes with an antibody against CDC14A specifically delays exit from Met I. Each of these perturbations generates eggs with chromosome alignment abnormalities and eggs that were injected with the CDC14A antibody had an elevated incidence of aneuploidy. Collectively, these data suggest that CDC14A regulates oocyte maturation and functions to promote the meiosis I-to-meiosis II transition as its homolog does in budding yeast.

Schindler, Karen; Schultz, Richard M.

2011-01-01

305

Strain specific spontaneous activation during mouse oocyte maturation  

PubMed Central

Objective To examine whether spontaneous oocyte activation is determined by genetic differences and interacted with culture environment. Design Experimental Study. Setting Temple University School of Medicine. Animals C57BL/6, DBA/2, C3H/HeJ, and A/J strains, along with reciprocal F1 hybrid female mice (5–6 weeks). Intervention(s) Immature oocytes from different mouse strains were collected and cultured in different maturation conditions including different serum, serum replacement, bovine serum albumin (BSA) and follicle stimulation hormone (FSH). Main Outcome Measure(s) The emission of first polar body, pronucleus formation, meiotic arrest, spontaneous activation, and expression of maturation regulators. Result(s) Oocytes from C57BL/6 mice display a high rate of delayed first meiotic division and spontaneous activation after the first meiotic division with in vitro maturation (IVM), and the second meiosis with in vivo maturation (VVM) following superovulation. Spontaneous activation with IVM is sensitive to culture environment. Oocytes spontaneously activated during the first meiotic division with IVM have unusual paired tetrad chromosomes with slight connections at centromeres, whereas oocytes activated in vivo display haploidization from the second meiosis. Spontaneous activation is also seen in F1 hybrid oocytes, indicating a dominant trait from C57BL/6. Delayed meiosis was associated with reduced cylcin B and securin expression. Conclusion(s) Both mouse strain and culture environment have a significant effect on the incidence of meiotic defects and spontaneous activation. Reduced expression of meiotic regulators may underlie this effect.

Cheng, Yong; Zhong, Zhisheng; Latham, Keith E

2012-01-01

306

Clathrin is essential for meiotic spindle function in oocytes.  

PubMed

In the mammalian ovary, oocytes are arrested at prophase of meiosis I until a hormonal stimulus triggers resumption of meiosis. During the subsequent meiotic maturation process, which includes completion of the first meiotic division and formation of the second metaphase spindle, oocytes acquire competence for fertilization. Recently, it was shown that clathrin, a cytosolic protein complex originally defined for its role in intracellular membrane traffic, is also involved in the stabilization of kinetochore fibers in mitotic spindles of dividing somatic cells. However, whether clathrin has a similar function in meiotic spindles in oocytes has not been investigated previously. Our results show that endogenous clathrin associates with the meiotic spindles in oocytes. To study the function of clathrin during meiotic maturation, we microinjected green fluorescent protein-tagged C-terminal and N-terminal dominant-negative clathrin protein constructs into isolated porcine oocytes prior to in vitro maturation. Both protein constructs associated with meiotic spindles similar to endogenous clathrin, but induced misalignment and clumping of chromosomes, occurrence of cytoplasmic chromatin and failure of polar body extrusion. These data demonstrate that clathrin plays a crucial role in meiotic spindle function in maturing oocytes, possibly through spindle stabilization. PMID:20522479

Hölzenspies, Jurriaan J; Roelen, Bernard A J; Colenbrander, Ben; Romijn, Roland A P; Hemrika, Wieger; Stoorvogel, Willem; van Haeften, Theo

2010-06-03

307

A phase of chromosome aggregation during meiosis in human oocytes.  

PubMed

A higher rate of chromosomal abnormality occurs in human oocytes compared with other animal oocytes. In this study, chromosome movement has been successfully observed during first and second meiosis using a time-lapse culture system and a differential interference contrast inverted microscope. In human oocytes, a specific sequence of early maturation changes was observed. Following the completion of nucleolar breakdown, chromosomes were assembled into a single aggregation that heralded the start of nuclear membrane breakdown. The chromosome aggregation phase (gere phase) persisted after germinal vesicle (GV) breakdown, lasting several hours, and a similar gere phase (chromosome gathering) occurred after the first polar body extrusion, lasting 1-4 h. In contrast, in mouse GV oocytes, nucleolar and nuclear membranes started to break down almost at the same time. A chromosome aggregation phase was not observed in mouse oocytes. The discovery of a gere phase during human oocyte maturation may provide important information related to the mechanism of abnormal chromosomal segregation, which often occurs during meiosis. PMID:17697496

Otsuki, Junko; Nagai, Yasushi

2007-08-01

308

Ultrastructural observations on gamete interactions using micromanipulated mouse oocytes.  

PubMed

Cumulus-free mouse oocytes were subjected to zona opening by cracking with microhooks (ZC) or acid drilling (ZD) and fixed 30-90 min after insemination (10(5) pre-capacitated motile sperms/ml). Ultrastructural observations were made on serially thin-sectioned oocytes: 15 ZC and 12 ZD. The zona lesion in ZC oocytes was a clean cut, whereas in ZD oocytes it formed a patchy area of partial zona loss, with reduced microvillar height on the underlying oocyte surface. Spermatozoa were observed within the perivitelline space and partially fusing with the oocyte after 30 min in both situations. Only acrosome-reacted sperm heads were observed to fuse: acrosome intact forms were generally in contact with the zona pellucida, either with the inner or outer surface. Acrosome-intact spermatozoa were also observed deeply embedded in the zona matrix, possibly indicating surface enzyme activity preceding the membrane fusion events of the acrosome reaction proper. The observations are consistent with the need for spermatozoa to make contact preferentially with the zona pellucida during the course of the acrosome reaction. PMID:2591863

Cummins, J M; Edirisinghe, W R; Odawara, Y; Wales, R G; Yovich, J L

1989-12-01

309

Regulation of Greatwall kinase during Xenopus oocyte maturation.  

PubMed

Greatwall kinase has been identified as a key element in M phase initiation and maintenance in Drosophila, Xenopus oocytes/eggs, and mammalian cells. In M phase, Greatwall phosphorylates endosulfine and related proteins that bind to and inhibit protein phosphatase 2A/B55, the principal phosphatase for Cdk-phosphorylated substrates. We show that Greatwall binds active PP2A/B55 in G2 phase oocytes but dissociates from it when progesterone-treated oocytes reach M phase. This dissociation does not require Greatwall kinase activity or phosphorylation at T748 in the presumptive T loop of the kinase. A mutant K71M Greatwall, also known as Scant in Drosophila, induces M phase in the absence of progesterone when expressed in oocytes, despite its reduced stability and elevated degradation by the proteasome. M phase induction by Scant Greatwall requires protein synthesis but is not associated with altered binding or release of PP2A/B55 as compared to wild-type Greatwall. However, in vitro studies with Greatwall proteins purified from interphase cells indicate that Scant, but not wild-type Greatwall, has low but detectable activity against endosulfine. These results demonstrate progesterone-dependent regulation of the PP2A/B55-Greatwall interaction during oocyte maturation and suggest that the cognate Scant Greatwall mutation has sufficient constitutive kinase activity to promote M phase in Xenopus oocytes. PMID:21551066

Yamamoto, Tomomi M; Blake-Hodek, Kristina; Williams, Byron C; Lewellyn, Andrea L; Goldberg, Michael L; Maller, James L

2011-05-05

310

Epigenetically immature oocytes lead to loss of imprinting during embryogenesis.  

PubMed

Loss of imprinting (LOI) is occasionally observed in human imprinting disorders. However, the process behind the LOI is not fully understood. To gain a better understanding, we produced embryos and pups from mouse oocytes that lacked a complete methylation imprint using a method that involved transferring the nuclei of growing oocytes into the cytoplasm of enucleated fully grown oocytes following in vitro fertilization (IVF). We then analyzed the imprinting statuses. Our findings show that the incomplete methylation imprint derived from growing oocytes results in epigenetic mosaicism or a loss of methylation imprint (LOM) at maternal alleles in embryos. In some embryos, both hypo- and hypermethylated maternal Kcnq1ot1 alleles were detected, whereas either hypo- or hypermethylated maternal Kcnq1ot1 alleles were detected in others. Such tendencies were also observed at the Igf2r and Mest loci. Gene expression levels of imprinted genes were linked with their methylation statuses in some but not all embryos. Possible explanations of the inconsistency between the data from DNA methylation and gene expression include epigenetic mosaicism in embryos. Pups were successfully produced from growing oocytes at a quite low frequency. They exhibited an obese phenotype and LOI with respect to Igf2r, Snrpn and Mest. Our finding suggests the possibility that LOI/LOM at maternal alleles in human concepti could be derived from epigenetically immature/mutated oocytes. PMID:21289466

Obata, Yayoi; Hiura, Hitoshi; Fukuda, Atsushi; Komiyama, Junichi; Hatada, Izuho; Kono, Tomohiro

2011-01-28

311

Culture of oocytes and risk of imprinting defects.  

PubMed

BACKROUND Follicle culture and oocyte in vitro maturation (IVM) are emerging assisted reproductive technologies with potentially important future applications in the fertility clinic. There is concern that these technologies might interfere at the epigenetic level and, in particular, with genomic imprinting. The timely acquisition of correct imprinting patterns in oocytes and the maintenance of genomic imprinting after fertilization are both required for normal embryonic development. METHODS A systematic literature search in Pubmed was performed and all publications reporting on the effects of follicle culture, IVM or ovarian tissue culture on genomic imprinting were retained. RESULTS Mouse ovarian tissue culture studies, mouse in vitro follicle culture studies and a single bovine IVM study generally showed correct imprinted DNA methylation establishment in oocytes. Influences of treatment and suboptimal culture conditions in mouse follicle culture indicate that imprinting establishment in oocytes is a robust process. This is in contrast with preimplantation embryo culture-induced epigenetic defects reported in mice. For human IVM, no definitive conclusion on imprinting establishment can be drawn as well-designed studies are currently not available. CONCLUSIONS Animal models provide reassuring data on imprinting establishment in cultured oocytes, but further studies should assess the effect of oocyte culture on imprinting maintenance. Optimized IVM procedures should be assessed in well-designed human studies. Finally, epigenetic analysis should be performed in children born from pregnancies after IVM to draw definitive conclusions on the epigenetic safety of human IVM. PMID:23054129

Anckaert, Ellen; De Rycke, Martine; Smitz, Johan

2012-10-10

312

Severe Acute Respiratory Syndrome Coronavirus Infection of Golden Syrian Hamsters  

PubMed Central

Small animal models are needed in order to evaluate the efficacy of candidate vaccines and antivirals directed against the severe acute respiratory syndrome coronavirus (SARS CoV). We investigated the ability of SARS CoV to infect 5-week-old Golden Syrian hamsters. When administered intranasally, SARS CoV replicates to high titers in the lungs and nasal turbinates. Peak replication in the lower respiratory tract was noted on day 2 postinfection (p.i.) and was cleared by day 7 p.i. Low levels of virus were present in the nasal turbinates of a few hamsters at 14 days p.i. Viral replication in epithelial cells of the respiratory tract was accompanied by cellular necrosis early in infection, followed by an inflammatory response coincident with viral clearance, focal consolidation in pulmonary tissue, and eventual pulmonary tissue repair. Despite high levels of virus replication and associated pathology in the respiratory tract, the hamsters showed no evidence of disease. Neutralizing antibodies were detected in sera at day 7 p.i., and mean titers at day 28 p.i. exceeded 1:400. Hamsters challenged with SARS CoV at day 28 p.i. were completely protected from virus replication and accompanying pathology in the respiratory tract. Comparing these data to the mouse model, SARS CoV replicates to a higher titer and for a longer duration in the respiratory tract of hamsters and is accompanied by significant pathology that is absent in mice. Viremia and extrapulmonary spread of SARS CoV to liver and spleen, which are seen in hamsters, were not detected in mice. The hamster, therefore, is superior to the mouse as a model for the evaluation of antiviral agents and candidate vaccines against SARS CoV replication.

Roberts, Anjeanette; Vogel, Leatrice; Guarner, Jeannette; Hayes, Norman; Murphy, Brian; Zaki, Sherif; Subbarao, Kanta

2005-01-01

313

Social thermoregulation and torpor in the Siberian hamster.  

PubMed

Social thermoregulation and huddling bring about energy benefits to animals sharing a nest because of the smaller surface-to-volume ratio of a huddle and the higher local temperature in the nest. We tested whether living in groups and huddling affect daily torpor, metabolic rate and seasonal changes in the body mass of a small heterothermic rodent, the Siberian hamster (Phodopus sungorus), housed under semi-natural conditions both singly and in groups of four litter-mates. We predicted that in hamsters housed in groups: (1) synchronized torpor bouts would be longer and deeper than non-synchronized ones but shallower than in solitary hamsters, (2) seasonal variations in metabolic rate would be lower than in solitary hamsters, and (3) the winter decrease in body mass would be smaller in grouped than in singly housed hamsters. We found that group housing led to a smaller decrease in body mass in winter, and affected the length and depth of daily torpor. In group-living hamsters more than 50% of all torpor episodes were synchronized and torpid animals were often found in huddles formed of all cage-mates. The longest and deepest torpor bouts in groups were recorded when all animals in a group entered torpor simultaneously. Although the minimum body temperature during torpor was higher, torpor duration was slightly longer than in solitary hamsters. We did not record significant differences in the body mass-adjusted rate of oxygen consumption between solitary and grouped animals, either in the cold or at the lower critical temperature. We conclude that social thermoregulation enables maintenance of a larger body mass, and thus a larger body fat content, which can ensure better body condition at the beginning of the reproductive season. PMID:21389194

Jefimow, Ma?gorzata; G?abska, Marta; Wojciechowski, Micha? S

2011-04-01

314

[Nuclear behavior of embryonic cells and growing oocytes from the clawed toad in the cytoplasm of maturing axolotl oocytes].  

PubMed

The behaviour of the nuclei of the X. laevis vitellogenic oocytes was studied by their transplantation into the cytoplasm of the axolotl maturing oocytes. After the germinal vesicle breakdown, in the case the transplanted nuclei were located close to each other a common giant spindle united the chromosomes of all transplanted nuclei. A mosaic spindle united sometimes the chromosomes of the two amphibian species. The embryonic nuclei transplanted in the cytoplasm of the maturing oocytes formed, after the nuclear envelope breakdown, individual spindles, sometimes united in multipolar figures. Thus, the nuclei of different cell types, embryonic cells and germ cells, behave in a different way in the same environment, the cytoplasm of the maturing oocytes. PMID:6504501

Nikitina, L A

315

Penetrating chest trauma in Nigeria.  

PubMed

Penetrating chest trauma occurs worldwide, and various accounts of it have been reported in the literature.(1)(-)(5) Blunt trauma is not usually associated with military or civilian violence, while penetrating chest trauma often is. Penetrating chest trauma is frequently caused by gunshots and non gunshot-related incidents such as stabs, traffic accidents, and impalements. This prospective study was conducted to determine a pattern of penetrating thoracic injuries, including their causes, the role of surgery, and intervention outcomes. In this study, we treated 168 patients (142 males and 26 females, giving a male-to-female ratio of 5.5:1). Gunshots caused 60.1% of the injuries while traffic accidents caused 27.3% of the injuries. Chest tube insertion alone was the main treatment initiated. This technique was used on 73.8% of the patients. To reduce the occurrence of penetrating chest trauma in Lagos, Nigeria, study results suggest that the Nigerian people and their property need greater security, and that pre-hospital level of care for trauma victims must improve. PMID:15905335

Thomas, Martins O; Ogunleye, Ezekiel O

2005-06-01

316

Simulation of laser penetration efficiency  

NASA Astrophysics Data System (ADS)

The results of numerical simulation of laser beam interaction with a hypothetical metallic material with properties similar to a steel alloy are reported. The numerical simulation was performed using a physical model that includes detailed consideration of surface evaporation, evaporative cooling of the surface and evaporation recoil induced melt ejection. The laser beam ‘penetration’ is considered in terms of melting through the sample or drilling through the sample due to both evaporation and recoil ejection of material. As a demonstration of the predictive capabilities of the model, the average velocity of penetration through a material with steel-like properties is numerically predicted for various laser interaction parameters such as, laser beam radius, laser pulse duration (including CW regime), laser pulse energy and pulse repetition. In particular, the average penetration velocities through a sample due to melting are compared for pulsed and CW lasers of the same power. For the sake of another demonstration of penetration simulation, the temporal dynamics of the position of melt front relative to the sample surface irradiated by a laser beam was computed for different laser pulse repetition rates and constant average laser power. An illustration of the penetration efficiency (W parameter) defined as the amount of energy per unit volume delivered into a target in order to achieve either melting of drilling through a target wall is shown in a wide range of laser pulse parameters covering regimes corresponding to domination of melting through and drilling through.

Semak, V. V.; Miller, T. F.

2013-09-01

317

The Transcriptome of a Human Polar Body Accurately Reflects Its Sibling Oocyte*  

PubMed Central

Improved methods are needed to reliably and accurately evaluate oocyte quality prior to fertilization and transfer into the woman of human embryos created through in vitro fertilization (IVF). All oocytes that are retrieved and matured in culture are exposed to sperm with little in the way of evaluating the oocyte quality. Furthermore, embryos created through IVF are currently evaluated for developmental potential by morphology, a criterion lacking in quantitation and accuracy. With the recent successes in oocyte vitrification and storage, clear metrics are needed to determine oocyte quality prior to fertilizing. The first polar body (PB) is extruded from the oocyte before fertilization and can be biopsied without damaging the oocyte. Here, we tested the hypothesis that the PB transcriptome is representative of that of the oocyte. Polar body biopsy was performed on metaphase II (MII) oocytes followed by single-cell transcriptome analysis of the oocyte and its sibling PB. Over 12,700 unique mRNAs and miRNAs from the oocyte samples were compared with the 5,431 mRNAs recovered from the sibling PBs (5,256 shared mRNAs or 97%, including miRNAs). The results show that human PBs reflect the oocyte transcript profile and suggests that mRNA detection and quantification through high-throughput quantitative PCR could result in the first molecular diagnostic for gene expression in MII oocytes. This could allow for both oocyte ranking and embryo preferences in IVF applications.

Reich, Adrian; Klatsky, Peter; Carson, Sandra; Wessel, Gary

2011-01-01

318

Effect of androstenedione on the growth and meiotic competence of bovine oocytes from early antral follicles.  

PubMed

Medium that contains 17?-estradiol has been reported to support in vitro growth of bovine oocytes, isolated from early antral follicles, until the final stage. The aim of this study was to determine the effects of androstenedione in medium on such growing bovine oocytes. Oocyte-granulosa cell complexes were collected from early antral follicles and cultured for 14 days in medium supplemented with 17?-estradiol (0, 10 and 100 ng/ml) or androstenedione (0, 10 and 100 ng/ml). The mean diameter of oocytes measured after seeding on the culture substrate was 96.9 ?m (n = 191). Either steroid was necessary for maintainance of the organization of oocyte-granulosa cell complexes over the 14-day culture period. In the 17?-estradiol- or the androstenedione-supplemented medium about 80% or 65%, respectively, of viable oocytes were recovered. In both groups the increase in oocyte size was significant after 14 days. The in vitro grown oocytes were cultured for a further 22-24 h for oocyte maturation; 13% and 30% of oocytes grown in the 10 and 100 ng/ml 17?-estradiol-supplemented medium reached metaphase II, respectively; more than 64% of oocytes grown in the androstenedione-supplemented medium matured to metaphase II. These results show that androstenedione, as 17?-estradiol, can maintain the viability of bovine oocyte-granulosa cell complexes and support the growth of oocytes, and that androstenedione promotes the acquisition of oocyte meiotic competence efficiently at a low dose. PMID:22067704

Taketsuru, Hiroaki; Hirao, Yuji; Takenouchi, Naoki; Iga, Kosuke; Miyano, Takashi

2011-11-09

319

Discovery of putative oocyte quality markers by comparative ExacTag proteomics  

PubMed Central

Purpose Identification of the biomarkers of oocyte quality, and developmental and reprogramming potential is of importance to assisted reproductive technology in humans and animals. Experimental design PerkinElmer ExacTag™ Kit was used to label differentially proteins in pig oocyte extracts (oocyte proteome) and pig oocyte-conditioned in vitro maturation media (oocyte secretome) obtained with high- and low-quality oocytes. Results We identified 16 major proteins in the oocyte proteome that were expressed differentially in high- versus low-quality oocytes. More abundant proteins in the high-quality oocyte proteome included kelch-like ECH-associated protein 1 (an adaptor for ubiquitin-ligase CUL3), nuclear export factor CRM1 and ataxia-telangiectasia mutated protein kinase. Dystrophin (DMD) was more abundant in low-quality oocytes. In the secretome, we identified 110 proteins, including DMD and cystic fibrosis transmembrane conductance regulator, two proteins implicated in muscular dystrophy and cystic fibrosis, respectively. Monoubiquitin was identified in the low-quality-oocyte secretome. Conclusions and clinical implications A direct, quantitative proteomic analysis of small oocyte protein samples can identify potential markers of oocyte quality without the need for a large amount of total protein. This approach will be applied to discovery of non-invasive biomarkers of oocyte quality in assisted human reproduction and in large animal embryo transfer programs.

Powell, Michael D.; Manandhar, Gaurishankar; Spate, Lee; Sutovsky, Miriam; Zimmerman, Shawn; Sachdev, Shrikesh C.; Hannink, Mark; Prather, Randall S.; Sutovsky, Peter

2011-01-01

320

The immune response in the hamster  

PubMed Central

Hamster IgM has been isolated and characterized. The protein possessed unique antigenic determinants but also shared common determinants with the 7S?1- and 7S?2-globulin classes. These shared determinants were present on the F(ab?)2 and Fab fragments of 7S?2-globulin. The rapidly sedimenting (S20,w = 20.7) IgM was dissociated into slowly sedimenting (? 7S) units after reduction and alkylation. Specific antibody formation in the IgM and IgG (7S?1-globulin) classes appeared at similar times after immunization with protein antigens, although IgM antibody was only detectable for a short period. After immunization with antigen in Freund's adjuvant, the serum concentration of IgM increased and remained at an elevated level even after disappearance of antibody to the immunizing antigen. Injection of adjuvant alone also increased the concentration of serum IgM, particularly after intraperitoneal administration of Freund's incomplete adjuvant. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 6FIG. 7FIG. 10

Coe, J. E.

1970-01-01

321

Denuding and centrifugation of maturing bovine oocytes alters oocyte spindle integrity and the ability of cytoplasm to support parthenogenetic and nuclear transfer embryo development.  

PubMed

The effects of cumulus cell removal and centrifugation of maturing bovine oocytes on nuclear maturation and subsequent embryo development after parthenogenetic activation and nuclear transfer were examined. Removal of cumulus cells at 4, 8, and 15 hr after in vitro maturation (IVM) or the centrifugation of denuded oocytes had no effect on maturation rates. Oocytes treated at 0 hr of IVM had a lower expulsion rate (50%) of the first polar body (PB1). The removal of cumulus cells and centrifugation affected the pattern of spindle microtubule distribution and division of chromosomes. There were almost no spindle microtubules allocated to PB1 and the spindles were swollen in anaphase I and telophase I oocytes. Approximately 20% of PB1 oocytes contained tripolar or multipolar spindles. After activation, oocytes denuded with or without centrifugation at 8 hr of IVM resulted in the lowest rate of development (3.0%). Denuded oocytes at 4, 15, and 24 hr of IVM with centrifugation or not resulted in similar blastocyst development rates (9.6%-13.2%). However, centrifugation of oocytes denuded at the beginning of IVM resulted in lower blastocyst development rate (8.1%, P < 0.05) than the noncentrifuged oocytes (17.3%). After nuclear transfer, the blastocyst development rates of oocytes denuded and centrifuged at 0, 4, and 8 hr of IVM were not different when compared to the same patch of noncentrifuged oocytes. However, oocytes denuded and centrifuged at 15 hr of IVM resulted in lower (P < 0.05) blastocyst development rates than the noncentrifuged oocytes. The results of this study suggest that removal of cumulus cells and centrifugation of denuded oocytes affect the spindle pattern. Embryo development of denuded and centrifuged oocytes may differ depending on the time of removal of cumulus cells. PMID:16425229

Li, Guang-Peng; Bunch, Thomas D; White, Kenneth L; Rickords, Lee; Liu, Ying; Sessions, Benjamin R

2006-04-01

322

Vitrification of calf oocytes: effects of maturation stage and prematuration treatment on the nuclear and cytoskeletal components of oocytes and their subsequent development.  

PubMed

This study was designed to establish the effects of the meiotic stage of bovine oocytes and of a prematuration treatment with roscovitine (ROS) on their resistance to cryopreservation. Oocytes from prepubertal calves at the stages of germinal vesicle breakdown (GVBD) or at metaphase II (MII) were vitrified by the open pulled straw (OPS) method. In another experiment, oocytes were kept under meiotic arrest with 50 microM ROS for 24 hr and vitrified at the GVBD stage. After warming, some oocyte samples were fixed, stained using specific fluorescent probes and examined under a confocal microscope. The remaining oocytes were fertilized, and cleavage and blastocyst rates recorded. Significantly lower cleavage rates were obtained for the vitrified GVBD and MII oocytes (9.9% and 12.6%, respectively) compared to control oocytes (73.9%). Significantly worse results in terms of cleavage rates were obtained when GVBD calf oocytes were exposed to cryoprotectants (CPAs: ethylene glycol plus dimethyl sulfoxide, DMSO) (13.1%) or vitrified (1.6%) after a prematuration treatment with ROS, when compared to untreated control oocytes (68.7%) or ROS-control oocytes (56.6%). None of the vitrification procedures yielded blastocysts, irrespective of the initial meiotic stage or previous prematuration treatment. Compared to the control oocytes, significantly fewer oocytes exhibited normal spindle configuration after being exposed to CPAs or after vitrification of either GVBD or MII calf oocytes. These results indicate that the vitrification protocol has a deleterious effect on the meiotic spindle organization of calf oocytes cryopreserved at both the GVBD and MII stage, which impairs the capacity for further development of the embryos derived from these vitrified oocytes. Prematuration treatment with ROS has no beneficial effect on the outcome of vitrification by the OPS method. PMID:15968627

Albarracín, José Luis; Morató, Roser; Izquierdo, Dolors; Mogas, Teresa

2005-10-01

323

Bidirectional communication between oocytes and ovarian follicular somatic cells is required for meiotic arrest of mammalian oocytes  

PubMed Central

Coordinated regulation of oocyte and ovarian follicular development is essential for fertility. In particular, the progression of meiosis, a germ cell-specific cell division that reduces the number of chromosomes from diploid to haploid, must be arrested until just before ovulation. Follicular somatic cells are well-known to impose this arrest, which is essential for oocyte–follicle developmental synchrony. Follicular somatic cells sustain meiotic arrest via the natriuretic peptide C/natriuretic peptide receptor 2 (NPPC/NPR2) system, and possibly also via high levels of the purine hypoxanthine in the follicular fluid. Upon activation by the ligand NPPC, NPR2, the predominant guanylyl cyclase in follicular somatic cells, produces cyclic guanosine monophosphate (cGMP), which maintains meiotic arrest after transfer to the oocyte via gap junctions. Here we report that both the NPPC/NPR2 system and hypoxanthine require the activity of inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme required for the production of guanylyl metabolites and cGMP. Furthermore, oocyte-derived paracrine factors, particularly the growth differentiation factor 9–bone morphogenetic protein 15 heterodimer, promote expression of Impdh and Npr2 and elevate cGMP levels in cumulus cells. Thus, although the somatic compartment of ovarian follicles plays an essential role in the maintenance of oocyte meiotic arrest, as has been known for many years, this function of the somatic cells is surprisingly regulated by signals from the oocyte itself.

Wigglesworth, Karen; Lee, Kyung-Bon; O'Brien, Marilyn J.; Peng, Jia; Matzuk, Martin M.; Eppig, John J.

2013-01-01

324

Bidirectional communication between oocytes and ovarian follicular somatic cells is required for meiotic arrest of mammalian oocytes.  

PubMed

Coordinated regulation of oocyte and ovarian follicular development is essential for fertility. In particular, the progression of meiosis, a germ cell-specific cell division that reduces the number of chromosomes from diploid to haploid, must be arrested until just before ovulation. Follicular somatic cells are well-known to impose this arrest, which is essential for oocyte-follicle developmental synchrony. Follicular somatic cells sustain meiotic arrest via the natriuretic peptide C/natriuretic peptide receptor 2 (NPPC/NPR2) system, and possibly also via high levels of the purine hypoxanthine in the follicular fluid. Upon activation by the ligand NPPC, NPR2, the predominant guanylyl cyclase in follicular somatic cells, produces cyclic guanosine monophosphate (cGMP), which maintains meiotic arrest after transfer to the oocyte via gap junctions. Here we report that both the NPPC/NPR2 system and hypoxanthine require the activity of inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme required for the production of guanylyl metabolites and cGMP. Furthermore, oocyte-derived paracrine factors, particularly the growth differentiation factor 9-bone morphogenetic protein 15 heterodimer, promote expression of Impdh and Npr2 and elevate cGMP levels in cumulus cells. Thus, although the somatic compartment of ovarian follicles plays an essential role in the maintenance of oocyte meiotic arrest, as has been known for many years, this function of the somatic cells is surprisingly regulated by signals from the oocyte itself. PMID:23980176

Wigglesworth, Karen; Lee, Kyung-Bon; O'Brien, Marilyn J; Peng, Jia; Matzuk, Martin M; Eppig, John J

2013-08-26

325

Visceral Leishmaniasis in the Golden Hamster as a Model for Human Kala-Azar.  

National Technical Information Service (NTIS)

Leishmania donovani infection in the golden hamster was studied as a model for human kala azar. Following intradermal inoculation of L. donovani amastigotes, hamsters developed positive DTH responses to parasite antigens and expressed resistance to reinfe...

J. P. Farrell

1988-01-01

326

Visceral Leishmaniasis in the Golden Hamster as a Model for Human Kala-Azar.  

National Technical Information Service (NTIS)

Partial contents: Experimental Infections with Geographical Isolates of Leishmaniasis; Immunity to L. donovani in the Golden Hamster; Courses of Infection of WR503 Strain in Hamsters Following IC Inoculation of Promastigotes; Effect of Cortisone (2.5 mg/1...

J. P. Farrell

1984-01-01

327

Correlates to Increased Lethality of Attenuated Venezuelan Encephalitis Virus Vaccine for Immunosuppressed Hamsters.  

National Technical Information Service (NTIS)

Splenectomy or pretreatment of adult hamsters with cyclophosphamide (Cytoxan) increased the lethality of the TC-83 vaccine strain of Venezuelan encephalitis virus (VEE), inoculated subcutaneously, from 12% for normal hamsters to 75 and 76% respectively. A...

P. B. Jahrling E. Dendy G. A. Eddy

1974-01-01

328

Cryopreservation of Mammalian Oocytes by Using Sugars: Intra- and extracellular raffinose with small amounts of dimethylsulfoxide yields high cryosurvival, fertilization, and development rates  

PubMed Central

Accumulation of intra- and extracellular sugars such as trehalose, glucose, and raffinose is central to survival strategies of a variety of organisms coping with extreme conditions including freezing and almost complete drying. The objective of the present study was to investigate the potential application of intra- and extracellular raffinose in combination with low concentrations of dimethylsulfoxide (Me2SO) to mammalian oocyte cryopreservation. To this end, the fertilization and embryonic development of cryopreserved metaphase II (M II) mouse oocytes were studied in comparison to unfrozen controls. For cryopreservation, M II oocytes were microinjected with 0.1 M raffinose, and then cooled to -196°C in the presence of either 0.3 M raffinose and 0.5 M Me2SO (cryopreservation group 1) or 0.3 M raffinose and 1.0 M Me2SO (cryopreservation group 2). The control groups included untreated oocytes (untreated control) and oocytes microinjected with raffinose, but not frozen (injection control). The post-thaw survival rates were 83.9% and 80.6% for the cryopreservation group 1 and 2, respectively. The fertilization and blastocyst rates in the cryopreservation group 1 (90.0% and 77.8%, respectively) and 2 (94.6% and 72.5%, respectively) were also high and similar to the ones of the injection controls (97.8% and 78.5%, respectively) and untreated controls (98.8% and 83.6%, respectively). These results are consistent with the findings of our earlier studies and support the use of sugars as intra- and extracellular cryoprotectants. Furthermore, the results of the present study indicate that the presence of intra- and extracellular sugars alleviates high concentrations of conventional penetrating cryoprotectants, and thus minimizes their toxicity.

Eroglu, Ali

2009-01-01

329

Circadian Regulation of Cortisol Release in Behaviorally Split Golden Hamsters  

PubMed Central

The master circadian clock located within the hypothalamic suprachiasmatic nucleus (SCN) is necessary for the circadian rhythm of glucocorticoid (GC) release. The pathways by which the SCN sustains rhythmic GC release remain unclear. We studied the circadian regulation of cortisol release in the behaviorally split golden hamster, in which the single bout of circadian locomotor activity splits into two bouts approximately12 h apart after exposing the animals to constant light conditions. We show that unsplit control hamsters present a single peak of cortisol release that is concomitant with a single peak of ACTH release. In contrast, split hamsters show two peaks of cortisol release that are approximately12 h appart and are appropriately phased to each locomotor activity bout but surprisingly do not rely on rhythmic release of ACTH. Our results are consistent with a model in which the circadian pacemaker within the SCN regulates the circadian release of GC via input to the hypothalamo-pituitary-adrenal axis and via a second regulatory pathway, which likely involves sympathetic innervation of the adrenal and can operate even in the absence of ACTH circadian rhythmic release. Furthermore, we show that although the overall 24-h cortisol output in split hamsters is lower than in unsplit controls, split hamsters release constant low levels of ACTH. This result suggests that the timing, rather than the absolute amount, of cortisol release is more critical for the induction of negative feedback effects that regulate the hypothalamo-pituitary-adrenal axis.

Lilley, Travis R.; Wotus, Cheryl; Taylor, Daniel; Lee, Jennifer M.

2012-01-01

330

Tamoxifen inhibits estrogen-induced hepatic injury in hamsters.  

PubMed

Estrogens have an unusual toxic effect on the liver of two hamster species, the Armenian and the Chinese hamster. The hepatotoxicity was detectable clinically by hyperbilirubinemia and confirmed histologically by the presence of hepatic degenerative-regenerative changes. Administration of tamoxifen with estrogen [either ethynyl estradiol or diethylstilbestrol (DES)] completely abrogated the hepatotoxic effects, suggesting that estrogen receptor (ER) was necessary for estrogen to damage liver. In Armenian hamsters, estrogens decreased hepatic synthesis of female protein (FP); tamoxifen also abolished this DES effect and resulted in a net increase in serum FP levels. DES administration produced higher serum bilirubin levels and lower serum FP levels in females than in males. Paradoxically, tamoxifen blocked these DES effects more effectively and efficiently in females than in males. Estrogens did not injure uteri of Armenian and Chinese hamsters and were nontoxic to livers of other hamsters species, such as Syrian and Turkish. This model provides another perspective of the acute cellular derangement that can be effected by estrogen-ER complex and may indicate a yet unknown mode of ER action. PMID:3335202

Coe, J E; Ross, M J

1988-01-01

331

Cell surface accumulation of overexpressed hamster lysosomal membrane glycoproteins.  

PubMed

We cloned and sequenced cDNAs encoding two lysosomal membrane glycoproteins, lgp-A and lgp-B, from Chinese hamster ovary cells. The deduced amino acid sequences of these proteins are similar to those of the other known members of this conserved family (also known as "LAMP" proteins). We used the cDNAs to generate stable lines of hamster lgp-expressing mouse NIH-3T3 cells, rat NRK cells, and monkey CV-1 cells. We also generated hybridomas that secrete antibodies specific for hamster lgp-A and lgp-B, enabling us to distinguish foreign from endogenous lgps in a wider variety of transfected cell lines. One line of mouse NIH-3T3 cells that expresses hamster lgp-B was studied in detail. Whereas most of the hamster lgp-B appeared to be transported to lysosomes in these cells, butyrate-induced overexpression resulted in the accumulation of a significant proportion of the total on the plasma membrane. In addition, overexpression of this foreign lgp-B also resulted in the appearance of the endogenous mouse lgp-A and lgp-B on the plasma membrane. Characterization of this accumulation suggested that it resulted from competition for one or more limited components in the transport pathway(s) to lysosomes. Endocytosis from the plasma membrane appeared to be one step that was saturable. PMID:8867788

Uthayakumar, S; Granger, B L

1995-01-01

332

Sex steroid induction of gallstones in the male Syrian hamster.  

PubMed

Light (LM), transmission (TEM) and scanning (SEM) electron microscopic techniques were used to characterize morphologic changes induced in the gallbladder of Syrian hamsters following a one-month estradiol (E) and estradiol + medroxyprogesterone (E+MP) treatment. The TEM results were correlated with the SEM findings. Compared to control (C), E-treated surface epithelial cells contain abundant RER, enlarged Golgi, multivesicular (foamy-heterophagosomes) bodies or lipofuscin inclusions. A 10-day E treatment showed large vesicles develop and, after longer E treatment, they could coalesce and create some of the large multivesicular bodies. Interestingly, E+MP epithelia are characterized by distinct bulging apices where a large number of apical granules accumulate, and contain an anionic mucous core. After a 4-week E+MP treatment, even though all the hamsters were fed a diet with trace cholesterol, significant increase in hamster liver weight, serum level of cholesterol and HDL were measured and, correspondingly, gallstones were found exclusively in E+MP-treated hamsters. Our results showed that not only does the Syrian hamster provide an appropriate model to study experimental lithogenesis without manipulating the diet. In addition, MP appears to induce morphologic changes associated with the formation of gallstones. PMID:8324721

Gilloteaux, J; Kosek, E; Kelly, T R

1993-04-01

333

Pineal melatonin synthesis in Syrian hamsters: A summary  

NASA Astrophysics Data System (ADS)

During the past decade there has been ample documentation of the proposition that the pineal gland mediates photoperiodic influences upon reproductive behavior of hamsters. It is commonly hypothesized that the pineal gland expresses its activity by transformation of photoperiodic information into an hormonal output, that hormone being melatonin. If this hypothesis is correct, there must be some essential diffrence in melatonin's output when hamsters are exposed to different photoperiodic environments. The experiments summarized in this communication analyze pineal melatonin contents in Syrian hamsters maintained in a variety of photoperiodic conditions during different physiological states. The results demonstrate that adult hamsters have a daily surge in pineal melatonin content throughout their lifetime when exposed to simulated annual photoperiodic cycles. There is some fluctuation in the amount of pineal melatonin produced during different physiological states and photoperiodic environments, but these fluctuations seem small when compared to those normally found for other regulatory hormones. When hamsters are exposed to different photoperiodic regimens, the daily melatonin surge maintains a relatively constant phase relationship with respect to the onset of daily activity. There is a concomitant change in its phase relationship with respect to light-dark transitions.

Rollag, M. D.

1982-12-01

334

Chicken oocyte growth: receptor-mediated yolk deposition.  

PubMed

During the rapid final stage of growth, chicken oocytes take up massive amounts of plasma components and convert them to yolk. The oocyte expresses a receptor that binds both major yolk lipoprotein precursors, vitellogenin (VTG) and very low density lipoprotein (VLDL). In the present study, in vivo transport tracing methodology, isolation of coated vesicles, ligand- and immuno-blotting, and ultrastructural immunocytochemistry were used for the analysis of receptor-mediated yolk formation. The VTG/VLDL receptor was identified in coated profiles in the oocyte periphery, in isolated coated vesicles, and within vesicular compartments both outside and inside membrane-bounded yolk storage organelles (yolk spheres). VLDL particles colocalized with the receptor, as demonstrated by ultrastructural visualization of VLDL-gold following intravenous administration, as well as by immunocytochemical analysis with antibodies to VLDL. Lipoprotein particles were shown to reach the oocyte surface by passage across the basement membrane, which possibly plays an active and selective role in yolk precursor accessibility to the oocyte surface, and through gaps between the follicular granulosa cells. Following delivery of ligands from the plasma membrane into yolk spheres, proteolytic processing of VTG and VLDL by cathepsin D appears to correlate with segregation of receptors and ligands which enter disparate sub-compartments within the yolk spheres. In small, quiescent oocytes, the VTG/VLDL receptor was localized to the central portion of the cell. At onset of the rapid growth phase, it appears that this pre-existing pool of receptors redistributes to the peripheral region, thereby initiating yolk formation. Such a redistribution mechanism would obliterate the need for de novo synthesis of receptors when the oocyte's energy expenditure is to be utilized for plasma membrane synthesis, establishment and maintenance of intracellular topography and yolk formation, and preparation for ovulation. PMID:8393385

Shen, X; Steyrer, E; Retzek, H; Sanders, E J; Schneider, W J

1993-06-01

335

Lipoprotein mediated lipid uptake in oocytes of polychaetes (Annelida).  

PubMed

The uptake of the 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-labeled sex-unspecific Nereis lipoprotein was investigated in oocytes of the nereidid polychaetes Nereis virens and Platynereis dumerilii. The fluorescence label was first observed in endocytic vesicles (<1 microm diameter), which later fused to larger vesicles (2-3 microm); these were finally incorporated into existing unlabeled yolk granules (5-6 microm). In Platynereis oocytes, the fusion of endocytic vesicles was delayed in oocytes at their final stage of development compared with those at an early stage of development. Lipoprotein double-labeled with fluorescein isothiocyanate (FITC) and DiI revealed that both the protein and the lipid moiety remained co-localized during incorporation into the yolk granules of the oocyte. No labeling of the cytoplasmic lipid droplets was observed. In N. virens, unlabeled Nereis lipoprotein was effective as a competitive inhibitor of DiI-labeled Nereis lipoprotein. Ligand blot experiments demonstrated the presence of a lipoprotein receptor with an apparent molecular mass of 120 kDa, which is different from that of the known yolk protein receptor. This indicates the presence, in the polychaete oocyte, of two distinct receptors mediating yolk protein and lipoprotein uptake, respectively. Thus, the sex-unspecific lipoprotein contributes to the lipid supply of the growing oocyte in addition to the known uptake of the yolk-protein-associated lipids. The absence of label in the cytoplasmic lipid droplets, even after prolonged incubation with labeled lipoprotein, suggests that these lipids arise either by the breakdown and resynthesis of lipoprotein-derived lipids and/or by de novo synthesis within the oocyte. PMID:19533173

Schenk, Sven; Hoeger, Ulrich

2009-06-16

336

Gender differences in the development of hyperlipemia and atherosclerosis in hybrid hamsters  

Microsoft Academic Search

In response to a diet enriched in saturated fat and cholesterol (CH), male Syrian hamsters develop hyperlipemia and changes of early atherosclerosis. However, it has not been determined if female hamsters are equally susceptible to an atherogenic diet. Male and female hamsters of the F1B hybrid strain (Bio Breeders, Fitchburg, MA) were fed either a chow diet or this diet

Sander J. Robins; Joan M. Fasulo; George M. Patton; Ernst J. Schaefer; Donald E. Smith; Jose M. Ordovas

1995-01-01

337

Transforming growth factor-? and epidermal growth factor in hamster tissues: Biochemical and immunohistochemical studies  

Microsoft Academic Search

In Syrian golden hamster kidneys and submaxillary glands, the levels of EGF, determined by radioimmunoassay, were much lower than in the same organs of two other rodent species, mouse and rat. In submaxillary glands, the EGF\\/TGF-? receptor-binding activities were also much lower in hamster than in mouse and rat. In contrast, the TGF-? content of hamster kidneys, determined by radioimmunoassay,

Fabrice Journé; Ruddy Wattiez; Christine Severyns; Denis Nonclercq; Gérard Toubeau; Jeanine-Anne Heuson-Stiennon; Paul Falmagne

1995-01-01

338

Anti-HER-2 DNA vaccine protects Syrian hamsters against squamous cell carcinomas  

Microsoft Academic Search

This paper illustrates the efficacy of DNA vaccination through electroporation in the prevention of oral transplantable carcinoma in Syrian hamsters. At 21 and 7 days before tumour challenge, 19 hamsters were vaccinated with plasmids coding for the extracellular and transmembrane domains of rat HER-2 receptor (EC-TM plasmids), whereas 19 control hamsters were injected intramuscularly with the empty plasmid. Immediately following

G N Berta; B Mognetti; M Spadaro; E Trione; A Amici; G Forni; F Di Carlo; F Cavallo

2005-01-01

339

Inhibitors of retrovirus infection are secreted by several hamster cell lines and are also present in hamster sera.  

PubMed Central

We have previously shown that Chinese hamster ovary (CHO) cells are resistant to infection by gibbon ape leukemia virus and amphotropic pseudotype retroviral vectors because of the secretion of factors that inhibit retrovirus infection. Such factors were not secreted by any mouse or human cell lines tested. Secretion of the inhibitors and resistance to infection are abrogated by treatment of CHO cells with the glycosylation inhibitor tunicamycin. Here we show that the inhibitory activities against gibbon ape leukemia virus and amphotropic viruses are partially separable and that glycosylation mutations in CHO cells mimic the effects of tunicamycin treatment. We find that several hamster cell lines derived from both Chinese and Syrian hamsters secrete inhibitors of retrovirus infection, showing that these inhibitors are not unique to the CHO cell line. Inhibitory factors are also present in the sera of Chinese and Syrian hamsters but were not detected in bovine serum. These results suggest the presence of specific factors that function to inhibit retrovirus infection in hamsters.

Miller, D G; Miller, A D

1993-01-01

340

Disrupted redox homeostasis and aberrant redox gene expression in porcine oocytes contribute to decreased developmental competence.  

PubMed

The objective of this study was to identify specific redox-related genes whose function contributes to oocyte quality and to characterize the role of redox homeostasis in oocyte development. We determined the redox genes glutaredoxin 2 (GLRX2), protein disulfide isomerase family A, members 4 and 6 (PDIA4, PDIA6), and thioredoxin reductase 1 (TXNRD1) were differentially expressed between adult (more competent) and prepubertal (less competent) porcine in vitro-matured (IVM) oocytes. The association between these genes and oocyte quality was further validated by comparing transcript abundance in IVM with that in in vivo-matured (VVM) prepubertal and adult oocytes. By maturing oocytes in variable redox environments, we demonstrated that a balanced redox environment is important for oocyte quality, and over-reduction of the environment is as detrimental as excess oxidation. Critical levels of reactive oxygen species (ROS) and glutathione (GSH) are required for oocyte competence. Elevated GSH and lower ROS in prepubertal oocytes suggest disrupted redox homeostasis exists in these cells. By further comparing GLRX2, PDIA4, PDIA6, and TXNRD1 expression levels in oocytes matured under these different redox environments, we found aberrant expression patterns in prepubertal oocytes but not in adult oocytes when the maturation medium contained high concentrations of antioxidants. These results suggest that prepubertal oocytes are less competent in regulating redox balance than adult oocytes, contributing to lower oocyte quality. In conclusion, aberrant redox gene expression patterns and disrupted redox homeostasis contribute to decreased developmental competence in prepubertal and IVM porcine oocytes. The balance between ROS and GSH plays an important role in oocyte quality. PMID:22811572

Yuan, Ye; Wheeler, Matthew B; Krisher, Rebecca L

2012-10-04

341

The effects of DNA double-strand breaks on mouse oocyte meiotic maturation.  

PubMed

Both endogenous and exogenous factors can induce DNA double-strand breaks (DSBs) in oocytes, which is a potential risk for human-assisted reproductive technology as well as animal nuclear transfer. Here we used bleomycin (BLM) and laser micro-beam dissection (LMD) to induce DNA DSBs in germinal vesicle (GV) stage oocytes and compared the germinal vesicle breakdown (GVBD) rates and first polar body extrusion (PBE) rates between DNA DSB oocytes and untreated oocytes. Employing live cell imaging and immunofluorescence labeling, we observed the dynamics of DNA fragments during oocyte maturation. We also determined the cyclin B1 expression pattern in oocytes to analyze spindle assembly checkpoint (SAC) activity in DNA DSB oocytes. We used parthenogenetic activation to determine if the DNA DSB oocytes could be activated. As a result, we found that the BLM- or LMD-induced DSB oocytes showed lower GVBD rates and took a longer time to undergo GVBD compared with untreated oocytes. PBE was also delayed in DSB oocytes, but once GVBD had occurred, PBE was not affected, even in oocytes with severe DSBs. Compared with control oocytes, the DSB oocytes showed higher SAC activity, as indicated by less Ccnb1-GFP degradation during metaphase I to anaphase I transition. Parthenogenetic activation could activate the metaphase to interphase transition in the DNA DSB mature oocytes, but many oocytes contained multiple pronuclei or numerous micronuclei. These data suggest that DNA damage inhibits or delays the G2/M transition, but once GVBD occurs, DNA-damaged oocytes can complete chromosome separation and polar body extrusion even under a higher SAC activity, causing the formation of numerous micronuclei in early embryos. PMID:23518501

Ma, Jun-Yu; Ou Yang, Ying-Chun; Wang, Zhong-Wei; Wang, Zhen-Bo; Jiang, Zong-Zhe; Luo, Shi-Ming; Hou, Yi; Liu, Zhong-Hua; Schatten, Heide; Sun, Qing-Yuan

2013-03-21

342

The role of transcription in EGF- and FSH-mediated oocyte maturation in vitro  

PubMed Central

Understanding mechanisms responsible for meiotic resumption in mammalian oocytes is critical for the identification of strategies to enhance developmental competence of in vitro matured oocytes. Improvement of in vitro oocyte maturation systems is dependent on a better understanding of mechanisms that regulate oocyte maturation both in vivo and in vitro as well as on the identification of methods to manipulate the meiotic progression of oocytes matured in vitro in a physiological manner. The purpose of this review is two-fold: first, to examine the mechanisms that underlie the acquisition of oocyte developmental competence and regulation of oocyte maturation in vivo and in vitro; and second, to present data examining the role of transcription in mediating the ability of EGF and FSH to induce oocyte maturation in vitro. Results presented support the conclusions that (1) EGF-induced oocyte maturation does not require nascent gene transcription in both mice and domestic cats; (2) FSH requires gene transcription to induce oocyte maturation in both species; (3) EGF must be present in the maturation medium to optimize the effectiveness of FSH to promote oocyte maturation; and (4) the mechanism used by FSH to induce oocyte maturation in vitro appears to predominate over that used by EGF when both EGF and FSH are present in maturation medium used for either murine or feline cumulus oocyte complexes.

Farin, C.E.; Rodriguez, K.F.; Alexander, J.E.; Hockney, J.E.; Herrick, J.R.; Kennedy-Stoskopf, S.

2007-01-01

343

Pathogenesis of Modoc virus (Flaviviridae; Flavivirus) in persistently infected hamsters.  

PubMed

The long-term persistence of Modoc virus (MODV) infection was investigated in a hamster model. Golden hamsters (Mesocricetus auratus) were infected by subcutaneous inoculation with MODV, in which fatal encephalitis developed in 12.5% (2 of 16). Surviving hamsters shed infectious MODV in their urine during the first five months after infection, and infectious MODV was recovered by co-cultivation of kidney tissue up to eight months after infection. There were no histopathologic changes observed in the kidneys despite detection of viral antigen for 250 days after infection. Mild inflammation and neuronal degeneration in the central nervous system were the primary lesions observed during early infection. These findings confirm previous reports of persistent flavivirus infection in animals and suggest a mechanism for the maintenance of MODV in nature. PMID:23358636

Adams, A Paige; Travassos da Rosa, Amelia P A; Nunes, Marcio R; Xiao, Shu-Yuan; Tesh, Robert B

2013-01-28

344

A penetration-aspiration scale  

Microsoft Academic Search

The development and use of an 8-point, equalappearing interval scale to describe, penetration and aspiration events are described. Scores are determined primarily by the depth to which material passes in the airway and by whether or not material entering the airway is expelled. Intra-and interjudge reliability have been established. Clinical and scientific uses of the scale are discussed.

John C. Rosenbek; Jo Anne Robbins; Ellen B. Roecker; Jame L. Coyle; Jennifer L. Wood

1996-01-01

345

Penetration of Rotating Shaped Charges  

Microsoft Academic Search

This paper presents an attempt to correlate theoretically the depth of penetration and the angular velocity of the liner in a rotating shaped charge. Each element of the rotating liner imparts an angular velocity to the corresponding jet element, and this results in a continuous increase of the cross-sectional area of the jet element as it travels in space and

Sampooran Singh

1960-01-01

346

GROUND PENETRATING RADAR ON MARS  

Microsoft Academic Search

In the past decade and in the next decade, several ground penetrating radar systems have been or will be launched toward Mars. GPR systems have been built or proposed for study of Mars and the Martian satellite, Phobos, from orbit, balloons, and rovers. The scientific problems include those of finding evidence of past or present life on Mars, unraveling the

Gary R. Olhoeft

1998-01-01

347

Drug penetration in solid tumours  

Microsoft Academic Search

To be most effective anticancer drugs must penetrate tissue efficiently, reaching all the cancer cells that comprise the target population in a concentration sufficient to exert a therapeutic effect. Most research into the resistance of cancers to chemotherapy has concentrated on molecular mechanisms of resistance, whereas the role of limited drug distribution within tumours has been neglected. We summarize the

Andrew I. Minchinton; Ian F. Tannock

2006-01-01

348

Assessing high wind energy penetration  

Microsoft Academic Search

In order to convincingly promote installing wind power capacity as a substantial part of the energy supply system, a set of careful analyses must be undertaken. This paper applies a case study concentrated on assessing the cost\\/benefit of high wind energy penetration. The case study considers expanding the grid connected wind power capacity in Praia, the capital of Cape Verde.

John Olav Tande

1995-01-01

349

Deposition of salicylic acid into hamster sebaceous.  

PubMed

In an earlier paper, we identified vehicles that are miscible with sebum, using differential scanning calorimetry (DSC). In this paper, the potential of these vehicles to deliver salicylic acid (SA) into the sebum-filled follicles of hamster ears is examined. The main objective of this study is to correlate the melting transitions of a model sebum with the follicular delivery of SA, using two different types of vehicles (fatty and polar). Generally, the fatty vehicles show higher deposition than the polar vehicles. Follicular delivery of salicylic acid correlates well with its solubility in the respective vehicles. This extent of deposition also shows a relationship with the effect of the vehicle on thermal behavior of the model sebum. The nature of the relationship depends on the vehicle (polar or fatty) tested. We conclude that DSC could be used to identify appropriate vehicles for drugs whose follicular delivery depends on solubility. The results also suggest that delivery into the sebaceous glands occurs by two different mechanisms, depending upon the polarity of the vehicle and the physicochemical properties of the drug. The results of these experiments are further extended to investigate follicular delivery of SA from two different types of oil-in-water emulsion formulations. From these studies we conclude that either increasing the volume of the oil phase or changing the emulsion to a water-in-oil emulsion would increase follicular deposition. Our research highlights the role of sebum, its compatibility with drug molecules, and vehicle selection in the transport of drugs into the follicles. The overall results of these experiments provide a reasonable understanding of the mechanisms underlying the transport of drugs to, and subsequently through, the sebaceous follicle. PMID:15645108

Motwani, M R; Rhein, L D; Zatz, J L

350

Susceptibility of Hamsters to Clostridium difficile Isolates of Differing Toxinotype  

PubMed Central

Clostridium difficile is the most commonly associated cause of antibiotic associated disease (AAD), which caused ?21,000 cases of AAD in 2011 in the U.K. alone. The golden Syrian hamster model of CDI is an acute model displaying many of the clinical features of C. difficile disease. Using this model we characterised three clinical strains of C. difficile, all differing in toxinotype; CD1342 (PaLoc negative), M68 (toxinotype VIII) & BI-7 (toxinotype III). The naturally occurring non-toxic strain colonised all hamsters within 1-day post challenge (d.p.c.) with high-levels of spores being shed in the faeces of animals that appeared well throughout the entire experiment. However, some changes including increased neutrophil influx and unclotted red blood cells were observed at early time points despite the fact that the known C. difficile toxins (TcdA, TcdB and CDT) are absent from the genome. In contrast, hamsters challenged with strain M68 resulted in a 45% mortality rate, with those that survived challenge remaining highly colonised. It is currently unclear why some hamsters survive infection, as bacterial & toxin levels and histology scores were similar to those culled at a similar time-point. Hamsters challenged with strain BI-7 resulted in a rapid fatal infection in 100% of the hamsters approximately 26 hr post challenge. Severe caecal pathology, including transmural neutrophil infiltrates and extensive submucosal damage correlated with high levels of toxin measured in gut filtrates ex vivo. These data describes the infection kinetics and disease outcomes of 3 clinical C. difficile isolates differing in toxin carriage and provides additional insights to the role of each toxin in disease progression.

Buckley, Anthony M.; Spencer, Janice; Maclellan, Lindsay M.; Candlish, Denise; Irvine, June J.; Douce, Gillian R.

2013-01-01

351

Effects of induced hyperthyroidism in normal and cardiomyopathic hamsters.  

PubMed

Thyroid hormones (TH) enhance cardiac function and reverse gene changes typical of pathological hypertrophy. However, reports in humans, but not animals, indicate that excess TH can cause heart failure. Also, the effects of TH on normal and cardiomyopathic hearts are likely to be different. The goal of this study was to characterize the effects of prolonged hyperthyroidism on cardiac function, chamber and cellular remodeling, and protein expression in both normal and cardiomyopathic hearts. Hyperthyroidism was induced in 3-mo-old normal BIO F1B and dilated cardiomyopathic BIO TO2 hamsters. After TH treatment for 10 days and 2 mo, hemodynamics, echos, myocyte length, histology, and protein expression were assessed. After 10 days and 2 mo, there were no differences between TO2-treated (Tx) and TO2-untreated (Untx) hamsters in chamber diameters or left ventricular function. After 2 mo of treatment, however, F1B-Tx showed evidence of dilated heart failure vs. F1B-Untx. Chamber diameters were increased, and ejection fraction and positive and negative changes in pressure over time were reduced. In F1B-Tx and TO2-Tx hamsters, beta-myosin isoform expression was reduced, whereas alpha-myosin increased significantly in F1B-Tx only. In TO2-Tx hamsters, the percent of viable myocardium was increased, and percent fibronecrosis was reduced vs. TO2-Untx. Myocyte length increased with TH treatment in both hamster strains. We conclude that 1) excess TH can induce heart failure in normal animals as observed in humans, 2) reversal of myosin heavy chain expression does not necessarily improve heart function, and 3) excess TH altered cellular remodeling but did not adversely affect chamber function or dimensions in TO2 hamsters. PMID:15976357

Kuzman, James A; Thomas, Tracy A; Vogelsang, Kathryn A; Said, Suleman; Anderson, Brent E; Gerdes, A Martin

2005-06-23

352

Naturally occurring mastitis disrupts developmental competence of bovine oocytes.  

PubMed

We examined the effects of naturally occurring mastitis on bovine oocyte developmental competence in vitro. Specifically, we investigated the effects of intramammary infection on the ovarian pool of oocytes (i.e., follicle-enclosed oocytes) and their ability to undergo in vitro maturation, fertilization, and further development to the blastocyst stage. Culled Holstein cows (n=50) from 9 commercial dairy farms in Israel were allotted to 3 groups according to somatic cell count (SCC) records of the last 3 monthly milk tests as well as of quarter samples collected before slaughter: (1) low SCC (n=7), (2) medium SCC (n=16), or (3) high SCC (n=27). Means of SCC values differed among low-, medium-, and high-SCC groups: 148,000, 311,000 and 1,813,000cell/mL milk, respectively. Milk yield and days in milk did not differ among the 3 groups. Bacterial isolates included coagulase-negative staphylococci, Escherichia coli, Streptococcus dysgalactiae, or no bacteria found. Ovaries were collected at the abattoir and brought to the laboratory. Cumulus oocyte complexes were recovered separately from each cow and subjected individually to in vitro maturation and fertilization, followed by 8d in culture. The number of aspirated oocytes did not differ among groups, with a range of 17 to 21 oocytes per cow. The proportion of oocytes that cleaved into 2- to 4-cell-stage embryos (86.1±3.4%) did not differ among groups. In contrast, mean percentages of embryos developed to the blastocyst stage on d 7 and 8 after fertilization were less in both medium- and-high SCC groups than in the low-SCC group (5.6±2.3 and 4.1±1.8 vs. 18.1±4.6%, respectively). Additional analysis indicated that cleavage and blastocyst-formation rates did not differ among the bacterial types in the low-, medium-, and high-SCC groups. These are the first results to demonstrate that naturally occurring mastitis disrupts the developmental competence of the ovarian pool of oocytes, (i.e., oocytes at the germinal vesicle stage). The disruption was associated with elevation of SCC rather than bacterial type. The results may provide a partial explanation for the low fertility of cows that have contracted mastitic pathogens before insemination. PMID:23957998

Roth, Z; Dvir, A; Kalo, D; Lavon, Y; Krifucks, O; Wolfenson, D; Leitner, G

2013-08-16

353

Mural granulosa cell gene expression associated with oocyte developmental competence  

PubMed Central

Background Ovarian follicle development is a complex process. Paracrine interactions between somatic and germ cells are critical for normal follicular development and oocyte maturation. Studies have suggested that the health and function of the granulosa and cumulus cells may be reflective of the health status of the enclosed oocyte. The objective of the present study is to assess, using an in vivo immature rat model, gene expression profile in granulosa cells, which may be linked to the developmental competence of the oocyte. We hypothesized that expression of specific genes in granulosa cells may be correlated with the developmental competence of the oocyte. Methods Immature rats were injected with eCG and 24 h thereafter with anti-eCG antibody to induce follicular atresia or with pre-immune serum to stimulate follicle development. A high percentage (30-50%, normal developmental competence, NDC) of oocytes from eCG/pre-immune serum group developed to term after embryo transfer compared to those from eCG/anti-eCG (0%, poor developmental competence, PDC). Gene expression profiles of mural granulosa cells from the above oocyte-collected follicles were assessed by Affymetrix rat whole genome array. Results The result showed that twelve genes were up-regulated, while one gene was down-regulated more than 1.5 folds in the NDC group compared with those in the PDC group. Gene ontology classification showed that the up-regulated genes included lysyl oxidase (Lox) and nerve growth factor receptor associated protein 1 (Ngfrap1), which are important in the regulation of protein-lysine 6-oxidase activity, and in apoptosis induction, respectively. The down-regulated genes included glycoprotein-4-beta galactosyltransferase 2 (Ggbt2), which is involved in the regulation of extracellular matrix organization and biogenesis. Conclusions The data in the present study demonstrate a close association between specific gene expression in mural granulosa cells and the developmental competence of oocytes. This finding suggests that the most differentially expressed gene, lysyl oxidase, may be a candidate biomarker of oocyte health and useful for the selection of good quality oocytes for assisted reproduction.

2010-01-01

354

KL/KIT co-expression in mouse fetal oocytes.  

PubMed

The tyrosine kinase receptor, KIT, and its ligand, KL are important regulators of germ cell development. The aim of this study was to examine in detail the expression of the genes encoding these proteins (White and Steel, respectively) during the fetal period (14.5-18.5 days post coitum, dpc) and the two weeks after birth in mouse ovaries using the highly sensitive in situ reverse-transcriptase polymerase chain reaction (in situ RT-PCR). KL and KIT mRNAs were not detected in 14.5-15.5 dpc ovaries but, between 16.5 and 17.5 dpc, most of the oocytes in the outer regions of the ovaries positively stained for both mRNAs. The majority of the co-expressing oocytes were identified at the zygotene/pachytene stage of meiotic prophase I. At 18.5 dpc, positive staining for KL mRNA was present only in the somatic cells in the outer regions of the ovaries. At birth, faint KL mRNA-labelled somatic cells were mainly found in the central region of the ovaries and, by P7-14, a higher level of expression was detected in the follicle cells of one- and two-layered growing follicles. Between 17.5 dpc and birth, most of the oocytes expressed KIT mRNA and, from P7 onward, there was a considerable accumulation of transcripts in the growing oocytes. The results of in situ RT-PCR were confirmed by RT-PCR on purified populations of oocytes, and at protein level by means of immunohistochemistry. The co-expression of KL and KIT in a fraction of fetal oocytes suggests that the KL/KIT system, besides the well known paracrine functions on germ cells, may exert a novel autocrine role during the mid-stage of the oocyte meiotic prophase. The possibility that this autocrine loop plays a role in sustaining the survival of fetal oocytes in this stage is supported by the finding that the addition to the culture medium of anti-KL or anti-KIT antibodies led to a significant increase in oocyte apoptosis in the absence of exogenous KL. PMID:12533025

Doneda, Luisa; Klinger, Francesca-Gioia; Larizza, Lidia; De Felici, Massimo

2002-12-01

355

Septin 7 is required for orderly meiosis in mouse oocytes  

PubMed Central

Septin 7 is a conserved GTP-binding protein. In this study, we examined the localization and functions of Septin 7 during mouse oocyte meiotic maturation. Immunofluorescent analysis showed that intrinsic Septin 7 localized to the spindles from the pro-MI stage to the MII stage. Knockdown of Septin 7 by siRNA microinjection caused abnormal spindles and affected extrusion of the first polar body. Septin 7 mRNA tagged with myc was injected into GV stage oocytes to overexpress Septin 7. Overexpressed Myc-Septin 7 localized to the spindle and beneath the plasma membrane displaying long filaments. Fluorescence intensity of spindle ?-tubulin in myc-Septin 7-injected oocytes was weaker than that of the control group, demonstrating that Septin 7 may influence recruitment of ?-tubulin to spindles. MII oocytes injected with myc-Septin 7 exhibited abnormal chromosome alignment, and parthenogenetic activation failed to allow extrusion of the second polar body, suggesting that overexpression of Septin 7 may affect extrusion of the polar body by disturbing the alignment of chromosomes and regulating ?-tubulin recruitment to spindles. In summary, Septin 7 may regulate meiotic cell cycle progression by affecting microtubule cytoskeletal dynamics in mouse oocytes.

Li, Sen; Ou, Xiang-Hong; Wei, Liang; Wang, Zhen-Bo; Zhang, Qing-Hua; Ouyang, Ying-Chun; Hou, Yi; Schatten, Heide; Sun, Qing-Yuan

2012-01-01

356

Septin 7 is required for orderly meiosis in mouse oocytes.  

PubMed

Septin 7 is a conserved GTP-binding protein. In this study, we examined the localization and functions of Septin 7 during mouse oocyte meiotic maturation. Immunofluorescent analysis showed that intrinsic Septin 7 localized to the spindles from the pro-MI stage to the MII stage. Knockdown of Septin 7 by siRNA microinjection caused abnormal spindles and affected extrusion of the first polar body. Septin 7 mRNA tagged with myc was injected into GV stage oocytes to overexpress Septin 7. Overexpressed Myc-Septin 7 localized to the spindle and beneath the plasma membrane displaying long filaments. Fluorescence intensity of spindle ?-tubulin in myc-Septin 7-injected oocytes was weaker than that of the control group, demonstrating that Septin 7 may influence recruitment of ?-tubulin to spindles. MII oocytes injected with myc-Septin 7 exhibited abnormal chromosome alignment, and parthenogenetic activation failed to allow extrusion of the second polar body, suggesting that overexpression of Septin 7 may affect extrusion of the polar body by disturbing the alignment of chromosomes and regulating ?-tubulin recruitment to spindles. In summary, Septin 7 may regulate meiotic cell cycle progression by affecting microtubule cytoskeletal dynamics in mouse oocytes. PMID:22895176

Li, Sen; Ou, Xiang-Hong; Wei, Liang; Wang, Zhen-Bo; Zhang, Qing-Hua; Ouyang, Ying-Chun; Hou, Yi; Schatten, Heide; Sun, Qing-Yuan

2012-08-16

357

Recombination and DNA Replication in the DROSOPHILA MELANOGASTER Oocyte  

PubMed Central

A method is described that permits the recovery of a well-synchronized population of oocytes. Utilizing this pupal system, the heat-responsive period for increasing crossing-over in the Drosophila genome has been defined for the X chromosome and a portion of chromosome 2. The response is initiated close to the time of oocyte formation (premeiotic interphase) and is terminated after ?36 hr. During the 36-hr period different regions show characteristic responses, which vary in degree, in duration, and in initiation and termination points, so as to generate the beginning of a thermal recombination map for the Drosophila genome. Centromere regions exhibit the greatest increases in crossing-over for their respective chromosomes but are distinctly asynchronous in time; interstitial regions respond the least. Correlated autoradiographic studies have localized DNA replication in the oocyte to a ?24-hr period, which also begins close to oocyte formation (premeiotic interphase); late labeling in restricted regions, undetectable with the present method, could extend the period, as could prolonged synthesis in the oocyte. The results demonstrate that DNA replication and the heat-sensitive period for enhancement of crossing-over are coincident processes over most and possibly all of their length.

Grell, Rhoda F.

1973-01-01

358

The GABA A receptor subunits heterologously expressed in Xenopus oocytes.  

PubMed

The ?-aminobutyric acid (GABA) A receptor is composed of a variety of subunits and combinations and shows a characteristic distribution in the CNS. To date, 20 subunits of the GABA A receptor have been cloned: ?1-6, ?1-4, ?1-3, ?, ?, ? , ?, and ?1-3. Oocyte of Xenopus laevis is one of the most frequently used heterologous expression systems, which are used to design and analyze specific combinations of GABA A receptor subunits. In oocytes, a certain GABA A receptor function is studied only by comparing the amplitude of the response to GABA and other drugs by physiological and pharmacological methods. According to the studies on Xenopus laevis oocytes, the ?1?2?2S receptor combination is mostly used. The ?1-containing receptors mediate sedative and anticonvulsant acts. The results of studies on oocytes show that PKA, NKCC1, P2X3 receptors, and GABA A receptor-associated protein, etc., are existing systems that show different reactivity to the GABA A receptors. The GABA A receptor subunits contain distinct binding sites for BZDs, neurosteroids, general anesthetics, etc., which are responsible for the numerous functions of the GABA A receptor. A variety of other drugs, such as topiramate, TG41, (+)- and (-)-borneol, apigenin, and 6-methylflavone could also have modulatory effects on the GABA A receptors. Some of the different models and hypotheses on GABA A receptor structure and function have been achieved by using the two-electrode voltage clamp method in oocytes. PMID:23373649

Abdullah, Jafri Malin; Zhang, Jingli

2013-04-01

359

The neurobehavioral effects of phytoestrogens in male Syrian hamsters.  

PubMed

We used a phytoestrogen (PE) and a phytoestrogen-free (PE-Free) diet to determine whether or not diet can have neurobehavioral effects on intermale aggression in Syrian hamsters (Mesocricetus auratus). In Experiment 1, 20 adult male hamsters were pre-tested for aggression and then placed on a PE (n=10) or a PE-Free diet (n=10) for 4 weeks in isolation. During week 5, experimental hamsters were exposed to a group-housed, nonaggressive opponent (NAO) for 5 min in a neutral cage arena. PE-fed hamsters exhibited more attacks (33.4+/-6.1) toward the NAO compared to the PE-Free-fed hamsters (18.1+/-4) (p<0.05). Interestingly, testosterone in the blood serum was higher in the PE-fed group (11.01+/-1.48 ng/ml) compared to the PE-Free group (6.5+/-0.87 ng/ml). In Experiment 2, 16 juvenile hamsters were weaned onto a PE (n=8) or a PE-Free diet (n=8). After 7 weeks on the diet, experimental hamsters were exposed to a NAO for 5 min in a neutral cage arena. Although the PE group exhibited higher levels of aggressive behavior, there were no statistically significant differences between groups. However, the PE group had higher levels of testosterone (9.0+/-0.95 ng/ml) compared to the PE-Free group (4.6+/-0.98 ng/ml) (p<0.05). In addition, analysis of the brains from both experiments revealed differences in binding for vasopressin 1A (V1A) receptors. Optical densities were converted to disintegrating units per min/mg. The PE-Free group had higher levels of V1A receptor binding (2689.93+/-254.8 dpm/mg) compared to the PE group (1907.32+/-136.3 dpm/mg) in the lateral septum (p<0.05). In addition, there were differences in the lateral hypothalamus, but the PE group had higher receptor binding (2550.9+/-63.59 dpm/mg) when compared to the PE-Free group (2011.9+/-174.14 dpm/mg) (p<0.05). In sum, these data present the first evidence that phytoestrogens can affect aggressive behavior and, concurrently, alter hormonal status and stimulate changes in the brain of male hamsters. PMID:15234258

Moore, Tim O; Karom, Mary; O'Farrell, Laura

2004-07-30

360

Isolation and identification of normal killer cells from Syrian hamsters  

SciTech Connect

This paper gives data on isolation of normal killer cells from the blood and various tissues of Syrian hamsters in a Percoll density gradient and their identification on the basis of morphologic criteria and cytotoxic activity (CTA). CTA of the isolated cells was studied in the cytotoxic test with target cells of a human MOLT-4 thymoma cell labeled with /sup 51/Cr. Isolation of large granular lymphocytes from blood, spleen, and bone marrow of Syrian hamsters in Percoll density gradient is shown in the results of five experiments used for cells of each type.

Matveeva, V.A.; Klyuchareva, T.E.

1986-09-01

361

In silico identification and molecular characterization of genes predominantly expressed in the fish oocyte  

Microsoft Academic Search

BACKGROUND: In fish, molecular mechanisms that control follicle-enclosed oocyte progression throughout oogenesis and oocyte developmental competence acquisition remain poorly understood. Existing data in mammals have indicated that the so called \\

Julien Bobe; Thaovi Nguyen; Sophie Mahé; Philippe Monget

2008-01-01

362

Instructing an Embryonic Stem Cell-Derived Oocyte Fate: Lessons from Endogenous Oogenesis  

PubMed Central

Female reproductive potential is limited in the majority of species due to oocyte depletion. Because functional human oocytes are restricted in number and accessibility, a robust system to differentiate oocytes from stem cells would enable a thorough investigation of the genetic, epigenetic, and environmental factors affecting human oocyte development. Also, the differentiation of functional oocytes from stem cells may permit the success of human somatic cell nuclear transfer for reprogramming studies and for the production of patient-specific embryonic stem cells (ESCs). Thus, ESC-derived oocytes could ultimately help to restore fertility in women. Here, we review endogenous and ESC-derived oocyte development, and we discuss the potential and challenges for differentiating functional oocytes from ESCs.

Nicholas, Cory R.; Chavez, Shawn L.; Baker, Valerie L.; Reijo Pera, Renee A.

2009-01-01

363

Pig oocyte vitrification by Cryotop method and the activation of the apoptotic cascade.  

PubMed

Oocyte and embryo cryopreservation has been applied successfully in many mammalian species. Nevertheless, pig oocytes, because of their greater susceptibility to cryoinjuries, have shown a reduced ability to be fertilized in vitro and a lower developmental competence. The aim of this study was to evaluate the apoptotic status of porcine oocytes vitrified by Cryotop method. We assessed three parameters linked to the activation of the apoptotic cascade: the exteriorization of phosphatidylserine using Annexin V, the caspase activation using FITC-VAD-FMK and the alteration of plasma membrane permeability employing YO-PRO-1. These assays were performed on control oocytes, oocytes exposed to vitrification solutions (toxicity control) and vitrified oocytes either immediately after warming or after incubation for 2h into maturation medium. The exposition to vitrification solutions triggered an increase of the percentage of oocytes both faintly (VAD+ PI-) and strongly (VAD++ PI-) labeled by FITC-VAD-FMK but not a significant modification of the number of oocytes Annexin V (A+ PI-, early apoptotic) and YO-PRO-1(YP+ PI-, apoptotic) positive in comparison with control oocytes. Oocytes submitted to the whole vitrification procedure showed a rise of the percentage of early apoptotic oocytes (A+ PI-) and FITC-VAD-FMK positive oocytes (VAD+/VAD++ PI-) and a contemporaneous increase of the number of dead oocytes (PI+). On the contrary, vitrified oocytes analyzed immediately after warming did not show a significant increase in the percentage of apoptotic oocytes (YO-PRO-1+/PI-) as compared with the control. Post warming incubation for 2h into maturation medium, in comparison with oocytes analyzed immediately after warming, did not induce any increase in the percentage of early apoptotic (A+ P-) oocytes while a decrease of the percentage of VAD+/PI- oocytes and a contemporaneous increase of VAD-/PI- oocytes were observed. Moreover, the post-warming incubation induced a rise of the percentage of apoptotic oocytes (YO-PRO-1+/PI-). All these data confirm the involvement of apoptotic mechanisms on the injuries induced by vitrification procedure in pig oocytes; explanation of this phenomenon could be useful to improve oocytes' cryopreservation protocols. PMID:22974705

Vallorani, C; Spinaci, M; Bucci, D; Porcu, E; Tamanini, C; Galeati, G

2012-08-21

364

Glutathione content of in vivo and in vitro matured canine oocytes collected from different reproductive stages.  

PubMed

Glutathione (GSH) concentrations of oocytes are considered as an important marker of the cytoplasmic maturation. The present study was designed to compare GSH concentrations of in vivo and in vitro matured canine oocytes. In vivo matured oocytes were collected 72 hr after ovulation by flushing fallopian tubes after laparotomy. Ovaries were collected from bitches with different reproductive stages, and collected oocytes were divided into 2 groups according to the size viz. < 120 microm and > 120 microm in diameter and cultured for 72 hr in Tissue Culture Medium-199 supplemented with 10% FBS, 2.2 mg/ml sodium bicarbonate, 2.0 microg/ml estrogen, 0.5 microg/ml FSH, 0.03 IU/ml hCG, and 1% penicillin-streptomycin solution in the presence or absence of 50 microM beta-mercaptoethanol. GSH concentrations were determined by the dithionitrobenzoic acid-glutathione disulfide (DTNB-GSSG) reductase recycling assay. GSH concentrations of immature canine oocytes were 2.9 and 3.8, 3.5 and 6.8, and 3.1 and 6.5 pM/oocyte for < 120 microm and > 120 microm in diameter oocyte groups at anestrous, follicular and luteal stage, respectively (P<0.05). In vivo matured oocytes had significantly higher GSH concentrations compared with in vitro matured oocytes. The GSH content was 19.2 pM/oocyte for in vivo matured oocytes, while 4.1 to 8.1 and 5.7 to 13.2 pM/oocyte for in vitro matured oocytes cultured in the absence or presence of beta-mercaptoethanol, respectively (P<0.05). Presence of beta-mercaptoethanol increased GSH synthesis in canine oocytes cultured in vitro, and oocytes collected from follicular and luteal stage was superior to anestrus oocytes. PMID:17611359

Kim, Min Kyu; Hossein, Mohammad Shamim; Oh, Hyun Ju; Fibrianto, Heru Yuda; Jang, Goo; Kim, Hye Jin; Hong, So Gun; Park, Jung Eun; Kang, Sung Keun; Lee, Byeong Chun

2007-06-01

365

Humic acid reduces gonadotropin activity and hormonal sensitivity of frog oocytes.  

PubMed

The specific stimulatory effect of sturgeon Acipenser güldenstädti Br. gonadotropic hormone (GTH) on frog Rana temporaria L. oocyte maturation in vitro was investigated in relation to humic acid (HA) concentrations from 12.5 to 50 mg/l. HA was observed to bind to both the follicular membrane of the oocytes and the GTH molecule, reducing the oocytes' hormone sensitivity and maturation ability. It was also shown that HA inactivated GTH, lowering its specific ability to stimulate oocyte maturation. PMID:16216349

Zenkevics, H; Klavins, M; Vose, V; Bucena, A

2005-10-07

366

Oocyte vitrification technology has made egg-sharing donation easier in China  

Microsoft Academic Search

When infertile women undergoing IVF or intracytoplasmic sperm injection (ICSI) have more than 15 mature oocytes retrieved, at least 10 oocytes are inseminated by their husband’s spermatozoa. The extra oocytes are cryopreserved by vitrification. If the patients become pregnant and have healthy live births, the patients are encouraged to donate their remaining cryopreserved oocytes. Forty-seven egg-sharing donors were recruited after

Ling-Bo Cai; Xiao-Qiao Qian; Wei Wang; Yun-Dong Mao; Zheng-Jie Yan; Cui-Zhen Liu; Wei Ding; Jie Huang; De-Chun Chai; Ri-Cheng Chian; Jia-Yin Liu

367

The origin of yolk in the oocytes of Nereis virens (Annelida, Polychaeta)  

Microsoft Academic Search

Three different types of evidence are reported concerning the origin of yolk protein in the oocyte of the annelid Nereis virens. The fine structure of the oocyte and its different types of storage organelles are described; only few pinocytotic vesicles are found. Electron-microscopic autoradiography of oocytes incubated with 3H-leucine showed that the oocytes synthesize protein which, in part, becomes localized

Albrecht Fischer; André Dhainaut

1985-01-01

368

Production of fertile offspring from oocytes grown in vitro by nuclear transfer in cattle.  

PubMed

Because of recent advancements in reproductive technology, oocytes have attained an increasingly enriched value as a unique cell population in the production of offspring. The growing oocytes in the ovary are an immediate potential source that serve this need; however, complete oocyte growth before use is crucial. Our research objective was to create in vitro-grown (IVG) oocytes that would have the ability to perform specialized activities, including nuclear reprogramming, as an alternative to in vivo-grown oocytes. Bovine oocyte-granulosa cell complexes with a mean oocyte diameter of approximately 100 ?m were cultured on Millicell membrane inserts, with culture medium supplemented with 4% polyvinylpyrrolidone (molecular weight, 360?000), 20 ng/ml androstenedione, 2 mM hypoxanthine, and 5 ng/ml bone morphogenetic protein 7. Oocyte viability after the 14-day culture period was 95%, and there was a 71% increase in oocyte volume. Upon induction of oocyte maturation, 61% of the IVG oocytes extruded a polar body. Eighty-four percent of the reconstructed IVG oocytes that used cumulus cells as donor cells underwent cleavage, and half of them became blastocysts. DNA methylation analyses of the satellite I and II regions of the blastocysts revealed a similar highly methylated status in the cloned embryos derived from in vivo-grown and IVG oocytes. Finally, one of the nine embryos reconstructed from the IVG oocytes developed into a living calf following embryo transfer. Fertility of the offspring was confirmed. In conclusion, the potential of a proportion of the IVG oocytes was comparable to that of in vivo-grown oocytes. PMID:23884646

Hirao, Yuji; Naruse, Kenji; Kaneda, Masahiro; Somfai, Tamas; Iga, Kosuke; Shimizu, Manabu; Akagi, Satoshi; Cao, Feng; Kono, Tomohiro; Nagai, Takashi; Takenouchi, Naoki

2013-09-19

369

Translocation and Endocytosis for Cell-penetrating Peptide Internalization  

PubMed Central

Cell-penetrating peptides (CPPs) share the property of cellular internalization. The question of how these peptides reach the cytoplasm of cells is still widely debated. Herein, we have used a mass spectrometry-based method that enables quantification of internalized and membrane-bound peptides. Internalization of the most used CPP was studied at 37 °C (endocytosis and translocation) and 4 °C (translocation) in wild type and proteoglycan-deficient Chinese hamster ovary cells. Both translocation and endocytosis are internalization pathways used by CPP. The choice of one pathway versus the other depends on the peptide sequence (not the number of positive changes), the extracellular peptide concentration, and the membrane components. There is no relationship between the high affinity of these peptides for the cell membrane and their internalization efficacy. Translocation occurs at low extracellular peptide concentration, whereas endocytosis, a saturable and cooperative phenomenon, is activated at higher concentrations. Translocation operates in a narrow time window, which implies a specific lipid/peptide co-import in cells.

Jiao, Chen-Yu; Delaroche, Diane; Burlina, Fabienne; Alves, Isabel D.; Chassaing, Gerard; Sagan, Sandrine

2009-01-01

370

Live imaging of GFP-labeled proteins in Drosophila oocytes.  

PubMed

The Drosophila oocyte has been established as a versatile system for investigating fundamental questions such as cytoskeletal function, cell organization, and organelle structure and function. The availability of various GFP-tagged proteins means that many cellular processes can be monitored in living cells over the course of minutes or hours, and using this technique, processes such as RNP transport, epithelial morphogenesis, and tissue remodeling have been described in great detail in Drosophila oocytes. The ability to perform video imaging combined with a rich repertoire of mutants allows an enormous variety of genes and processes to be examined in incredible detail. One such example is the process of ooplasmic streaming, which initiates at mid-oogenesis. This vigorous movement of cytoplasmic vesicles is microtubule and kinesin-dependent and provides a useful system for investigating cytoskeleton function at these stages. Here I present a protocol for time lapse imaging of living oocytes using virtually any confocal microscopy setup. PMID:23567977

Pokrywka, Nancy Jo

2013-03-29

371

Cryopreservation of Mammalian Oocyte for Conservation of Animal Genetics  

PubMed Central

The preservation of the female portion of livestock genetics has become an international priority; however, in situ conservation strategies are extremely expensive. Therefore, efforts are increasingly focusing on the development of a reliable cryopreservation method for oocytes, in order to establish ova banks. Slow freezing, a common method for cryopreservation of oocytes, causes osmotic shock (solution effect) and intracellular ice crystallization leading to cell damage. Vitrification is an alternative method for cryopreservation in which cells are exposed to a higher concentration of cryoprotectants and frozen with an ultra rapid freezing velocity, resulting in an ice crystal free, solid glass-like structure. Presently, vitrification is a popular method for cryopreservation of embryos. However, vitrification of oocytes is still challenging due to their complex structure and sensitivity to chilling.

Prentice, Jennifer R.; Anzar, Muhammad

2011-01-01

372

Nuclear genome transfer in human oocytes eliminates mitochondrial DNA variants.  

PubMed

Mitochondrial DNA mutations transmitted maternally within the oocyte cytoplasm often cause life-threatening disorders. Here we explore the use of nuclear genome transfer between unfertilized oocytes of two donors to prevent the transmission of mitochondrial mutations. Nuclear genome transfer did not reduce developmental efficiency to the blastocyst stage, and genome integrity was maintained provided that spontaneous oocyte activation was avoided through the transfer of incompletely assembled spindle-chromosome complexes. Mitochondrial DNA transferred with the nuclear genome was initially detected at levels below 1%, decreasing in blastocysts and stem-cell lines to undetectable levels, and remained undetectable after passaging for more than one year, clonal expansion, differentiation into neurons, cardiomyocytes or ?-cells, and after cellular reprogramming. Stem cells and differentiated cells had mitochondrial respiratory chain enzyme activities and oxygen consumption rates indistinguishable from controls. These results demonstrate the potential of nuclear genome transfer to prevent the transmission of mitochondrial disorders in humans. PMID:23254936

Paull, Daniel; Emmanuele, Valentina; Weiss, Keren A; Treff, Nathan; Stewart, Latoya; Hua, Haiqing; Zimmer, Matthew; Kahler, David J; Goland, Robin S; Noggle, Scott A; Prosser, Robert; Hirano, Michio; Sauer, Mark V; Egli, Dieter

2012-12-19

373

Cumulus and granulosa cell markers of oocyte and embryo quality.  

PubMed

Lack of an objective, accurate, and noninvasive embryo assessment strategy remains one of the major challenges encountered in in vitro fertilization. Cumulus and mural granulosa cells reflect the characteristics of the oocyte, providing a noninvasive means to assess oocyte quality. Specifically, transcriptomic profiling of follicular cells may help identify biomarkers of oocyte and embryo competence. Current transcriptomics technologies include quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) for analysis of individual genes and microarrays and high-throughput deep sequencing for whole genome expression profiling. Recently, using qRT-PCR and microarray technologies, a multitude of studies correlated changes in cumulus or granulosa cell gene expression with clinically relevant outcome parameters, including in vitro embryo development and pregnancy. While the initial findings are promising, a clinical benefit from the use of identified biomarker genes remains to be demonstrated in randomized controlled trials. PMID:23498999

Uyar, Asli; Torrealday, Saioa; Seli, Emre

2013-03-15

374

PH-20 but not acrosin is involved in sperm penetration of the macaque zona pellucida.  

PubMed

In this study, we investigated the functions of PH-20 and acrosin during the interaction of macaque sperm with the zona pellucida. Both of these sperm enzymes have been reported to be present on the inner acrosomal membrane of acrosome reacted sperm, and have been suggested to play a role during secondary sperm-zona binding in other species. Anti-macaque PH-20 IgG, anti-pig acrosin IgG and soybean trypsin inhibitor (SBTI) were used as probes for immunolocalization of the two proteins at the ultrastructural level, and as reagents for blocking sperm penetration of the macaque zona pellucida in vitro. As a control, we performed similar studies with antibodies to CD-46, which is also located on the inner acrosomal membrane, but has no known function in sperm-zona pellucida interaction. After labeling with anti-acrosin IgG, gold label was not present on the sperm surface before the acrosome reaction, but was detected over the entire head of sperm that were induced to acrosome react with calcium ionophore A23187. In contrast, when sperm were induced to acrosome react by binding to intact zona pellucida, acrosin was present in the acrosomal shroud but not on the inner acrosomal membrane. Similar results were obtained when SBTI was used as a probe for enzyme localization. PH-20 and CD-46 were demonstrated on the inner acrosomal membrane of sperm induced to acrosome react by ionophore treatment and by zona binding. Neither anti-acrosin IgG nor anti-CD-46 IgG affected sperm penetration of the zona at concentrations up to 300 microg/ml, but zona penetration was blocked completely when anti-PH-20 IgG (100 microg/ml) was present during sperm-oocyte interaction. Ultrastructural observations of oocytes incubated with anti-PH-20 IgG showed that acrosomal shrouds were present on the zona surface but no sperm had begun to penetrate into the zona substance. We conclude that anti-PH-20 IgG prevented sperm penetration of the macaque zona pellucida by interference with secondary sperm-zona binding, rather than primary sperm-zona binding or the zona-induced acrosome reaction. Acrosin was not detected on the inner acrosomal membrane of sperm that are induced to acrosome react after zona binding, and acrosin does not appear to be critical for sperm penetration of the macaque zona pellucida. PMID:10369396

Yudin, A I; Vandevoort, C A; Li, M W; Overstreet, J W

1999-07-01

375

Effect of gonadotropins during in vitro maturation of feline oocytes on oocyte-cumulus cells functional coupling and intracellular concentration of glutathione.  

PubMed

Information about the mechanisms of meiotic arrest and resumption of meiosis in feline oocytes is still limited. The aim of this study was to investigate the effect of the presence of gonadotropins during IVM, on meiotic progression in relation to the status of gap junction mediated communications between oocyte and cumulus cells, to the cAMP intracellular content, and to the intra-oocyte concentration of glutathione (GSH) in feline oocytes. Our results indicated that about 50% of cumulus-oocyte complexes (COCs) showed functionally open communications at the time of collection, while the remainder were partially or totally closed. After 3h of culture, the percentage of COCs with functional gap junctions was significantly greater in the group matured in the presence of gonadotropins than in those matured without them, where an interruption of communications was observed. Moreover, this precocious uncoupling was associated with a moderate increase of cAMP concentration in the oocyte, lower than in the group exposed to gonadotropins. Intra-oocyte glutathione levels decreased significantly after 24h of IVM, whether gonadotropins were present or absent during the culturing process. The presence of thiol compounds in the IVM medium induced an intra-oocyte GSH concentration significantly higher than that found in oocytes cultured without these compounds, and similar to the GSH content of immature oocytes. Moreover, the intracellular GSH concentration increased as meiosis progressed. The present study suggests that in feline oocytes, gonadotropins affect the dynamic changes in communications between oocyte and cumulus cells during IVM. However, the intracellular concentration of GSH is not influenced by the gonadotropin stimulation. Moreover, the presence of gonadotropins and thiol compounds results in an increase of GSH levels along with meiotic progression of the oocytes. PMID:16386859

Luvoni, Gaia C; Chigioni, Sara; Perego, Lucia; Lodde, Valentina; Modina, Silvia; Luciano, Alberto M

2006-01-18

376

Improved developmental ability of porcine oocytes grown in nude mice after fusion with cytoplasmic fragments prepared by centrifugation: A model for utilization of primordial oocytes.  

PubMed

Primordial oocytes are a potential resource for medical and zoological application, but those of large animals have not yet been reported to show efficient embryonic development. In the present study, we established a pig model for production of blastocysts from primordial oocytes that had been grafted into nude mice and matured in vitro, in combination with fusion of cytoplasmic fragments. Neonatal porcine ovaries in which most follicles are at the primordial stage were minced and grafted into nude mice (Crlj:CD1-Foxn1(nu)). About 60 days after detection of vaginal opening, the mice were given 62.5 U/mL porcine FSH for 2 weeks by infusion to enhance follicular development. Developmentally competent oocytes collected from porcine ovaries (conventional oocytes) were matured in vitro and subjected to serial centrifugation to prepare cytoplasmic fragments without a metaphase plate (cytoplasts). Three cytoplasts were fused by electrostimulation to an oocyte retrieved from a host mouse (xenogeneic oocyte) and matured in vitro. Then these fused oocytes were fertilized and subsequently cultured in vitro. No blastocysts were generated from xenogeneic oocytes without fusion of cytoplasm. When xenogeneic oocytes had been fused with three cytoplasts, the blastocyst rate increased significantly to 14.3%, comparable to that for untreated conventional oocytes (20.0%). The numbers of cells in blastocysts for these fused oocytes (37.2 cells/blastocyst) were not significantly different from those for conventional oocytes (25.4 cells/blastocyst). Our findings show that it is possible to use primordial oocytes of large mammals in combination with xenografting of ovarian tissue and also ooplasmic fusion. PMID:23981298

Kaneko, Hiroyuki; Nakai, Michiko; Tanihara, Fuminori; Noguchi, Junko; Kikuchi, Kazuhiro

2013-08-24

377

Effect of ovarian stimulation on oocyte gene expression in cattle.  

PubMed

The objective was to analyze the impact of follicle stimulating hormone (FSH, ovarian stimulation) on the transcriptome of in vivo bovine oocytes three times around the luteinizing hormone (LH) surge. In vivo bovine oocytes were collected 2 h pre-LH surge, 6 h post-LH surge, and 22 h post-LH surge in both naturally ovulating and superovulated animals. To assess potential changes in gene levels, samples were hybridized using a custom bovine microarray. Two series of hybridizations were performed: the first comparing natural vs. stimulated cycles, the second according to time of collection. Among the potential candidates, 13 genes were selected according to their degree of differential expression and their potential link to oocyte competence. Measurements of their relative mRNA levels was made using QPCR. Gene candidates BTG4 (P = 0.0006), PTTG1 (P = 0.0027), PAPOLA (P = 0.0245), and LEO1 (P = 0.0393) had higher mRNA levels in oocytes treated with FSH for all collection times when compared to oocytes produced through the natural cycle. Among our selected candidates, only one gene, GDF9 (P = 0.0261), was present at a higher level in oocytes collected at -2 h and 6 h than 22 h post-LH for all treatments, regardless of the presence of FSH. Although the number of genes influenced by ovarian stimulation seemed low, the observed differences occurred at a time of minimal transcriptional activity and supported the potential impact on the future embryo. These impacts could have been epigenetic in nature, as embryo quality was not reported to be different from stimulated animals. PMID:22444561

Chu, T; Dufort, I; Sirard, M-A

2012-03-22

378

Regulation of ALF Promoter Activity in Xenopus Oocytes  

PubMed Central

Background In this report we evaluate the use of Xenopus laevis oocytes as a matched germ cell system for characterizing the organization and transcriptional activity of a germ cell-specific X. laevis promoter. Principal Findings The promoter from the ALF transcription factor gene was cloned from X. laevis genomic DNA using a PCR-based genomic walking approach. The endogenous ALF gene was characterized by RACE and RT-PCR for transcription start site usage, and by sodium bisulfite sequencing to determine its methylation status in somatic and oocyte tissues. Homology between the X. laevis ALF promoter sequence and those from human, chimpanzee, macaque, mouse, rat, cow, pig, horse, dog, chicken and X. tropicalis was relatively low, making it difficult to use such comparisons to identify putative regulatory elements. However, microinjected promoter constructs were very active in oocytes and the minimal promoter could be narrowed by PCR-mediated deletion to a region as short as 63 base pairs. Additional experiments using a series of site-specific promoter mutants identified two cis-elements within the 63 base pair minimal promoter that were critical for activity. Both elements (A and B) were specifically recognized by proteins present in crude oocyte extracts based on oligonucleotide competition assays. The activity of promoter constructs in oocytes and in transfected somatic Xenopus XLK-WG kidney epithelial cells was quite different, indicating that the two cell types are not functionally equivalent and are not interchangeable as assay systems. Conclusions Overall the results provide the first detailed characterization of the organization of a germ cell-specific Xenopus promoter and demonstrate the feasibility of using immature frog oocytes as an assay system for dissecting the biochemistry of germ cell gene regulation.

Li, Dan; Raza, Abbas; DeJong, Jeff

2009-01-01

379

Cholesterol depletion disorganizes oocyte membrane rafts altering mouse fertilization.  

PubMed

Drastic membrane reorganization occurs when mammalian sperm binds to and fuses with the oocyte membrane. Two oocyte protein families are essential for fertilization, tetraspanins and glycosylphosphatidylinositol-anchored proteins. The firsts are associated to tetraspanin-enriched microdomains and the seconds to lipid rafts. Here we report membrane raft involvement in mouse fertilization assessed by cholesterol modulation using methyl-?-cyclodextrin. Cholesterol removal induced: (1) a decrease of the fertilization rate and index; and (2) a delay in the extrusion of the second polar body. Cholesterol repletion recovered the fertilization ability of cholesterol-depleted oocytes, indicating reversibility of these effects. In vivo time-lapse analyses using fluorescent cholesterol permitted to identify the time-point at which the probe is mainly located at the plasma membrane enabling the estimation of the extent of the cholesterol depletion. We confirmed that the mouse oocyte is rich in rafts according to the presence of the raft marker lipid, ganglioside GM1 on the membrane of living oocytes and we identified the coexistence of two types of microdomains, planar rafts and caveolae-like structures, by terms of two differential rafts markers, flotillin-2 and caveolin-1, respectively. Moreover, this is the first report that shows characteristic caveolae-like invaginations in the mouse oocyte identified by electron microscopy. Raft disruption by cholesterol depletion disturbed the subcellular localization of the signal molecule c-Src and the inhibition of Src kinase proteins prevented second polar body extrusion, consistent with a role of Src-related kinases in fertilization via signaling complexes. Our data highlight the functional importance of intact membrane rafts for mouse fertilization and its dependence on cholesterol. PMID:23638166

Buschiazzo, Jorgelina; Ialy-Radio, Come; Auer, Jana; Wolf, Jean-Philippe; Serres, Catherine; Lefèvre, Brigitte; Ziyyat, Ahmed

2013-04-25

380

Use of an oocyte expression assay to reconstitute inductive signaling.  

PubMed Central

We have developed a paracrine signaling assay capable of mimicking inductive events in the early vertebrate embryo. RNA encoding one or more secreted proteins is microinjected into a Xenopus laevis oocyte. After a brief incubation to allow translation, a piece of embryonic tissue competent to respond to the signaling protein is grafted onto the oocyte. The secreted protein's effect on the grafted explant is then scored by assaying expression of tissue-specific markers. Explants of ectodermal tissue from blastula or gastrula stage embryos were grafted onto oocytes that had been injected with RNA encoding activin or noggin. We found that the paracrine assay faithfully reconstitutes mesoderm induction by activin and neural induction by noggin. Blastula-stage explants grafted onto activin-expressing oocytes expressed the mesodermal marker genes brachyury, goosecoid, and muscle actin. Gastrula-stage explants grafted onto noggin-expressing oocytes expressed neural cell adhesion molecule (NCAM) and formed cement gland. By injecting pools of RNA synthesized from a cDNA expression library into the oocyte, we also used the assay to screen for secreted neural-inducing proteins. We assayed 20,000 independent transformants of a library constructed from LiCl-dorsalized Xenopus laevis embryos, and we identified two cDNAs that induced neural tissue in ectodermal explants from gastrula-stage embryos. Both cDNAs encode noggin. These results suggest that the paracrine assay will be useful for the cloning of novel signaling proteins as well as for the analysis of known factors. Images Fig. 1 Fig. 2 Fig. 3

Lustig, K D; Kirschner, M W

1995-01-01

381

Release of ATP induced by hypertonic solutions in Xenopus oocytes  

PubMed Central

ATP mediates intercellular communication. Mechanical stress and changes in cell volume induce ATP release from various cell types, both secretory and non-secretory. In the present study, we stressed Xenopus oocytes with a hypertonic solution enriched in mannitol (300 mm). We measured simultaneously ATP release and ionic currents from a single oocyte. A decrease in cell volume, the activation of an inward current and ATP release were coincident. We found two components of ATP release: the first was associated with granule or vesicle exocytosis, because it was inhibited by tetanus neurotoxin, and the second was related to the inward current. A single exponential described the correlation between ATP release and the hypertonic-activated current. Gadolinium ions, which block mechanically activated ionic channels, inhibited the ATP release and the inward current but did not affect the decrease in volume. Oocytes expressing CFTR (cystic fibrosis transmembrane regulator) released ATP under hypertonic shock, but ATP release was significantly inhibited in the first component: that related to granule exocytosis. Since the ATP measured is the balance between ATP release and ATP degradation by ecto-enzymes, we measured the nucleoside triphosphate diphosphohydrolase (NTPDase) activity of the oocyte surface during osmotic stress, as the calcium-dependent hydrolysis of ATP, which was inhibited by more than 50 % in hypertonic conditions. The best-characterized membrane protein showing NTPDase activity is CD39. Oocytes injected with an antisense oligonucleotide complementary to CD39 mRNA released less ATP and showed a lower amplitude in the inward current than those oocytes injected with water.

Aleu, Jordi; Martin-Satue, Mireia; Navarro, Piedad; de Lara, Ivanna Perez; Bahima, Laia; Marsal, Jordi; Solsona, Carles

2003-01-01

382

NOBOX Deficiency Disrupts Early Folliculogenesis and Oocyte-Specific Gene Expression  

Microsoft Academic Search

Primordial ovarian follicles in mice form when somatic cells surround individual oocytes. We show that lack of Nobox, an oocyte-specific homeobox gene, accelerates postnatal oocyte loss and abolishes the transition from primordial to growing follicles in mice. Follicles are replaced by fibrous tissue in female mice lacking Nobox in a manner similar to nonsyndromic ovarian failure in women. Genes preferentially

Aleksandar Rajkovic; Stephanie A. Pangas; Daniel Ballow; Nobuhiro Suzumori; Martin M. Matzuk

2004-01-01

383

Proteomics-Based Systems Biology Modeling of Bovine Germinal Vesicle Stage Oocyte and Cumulus Cell Interaction  

Microsoft Academic Search

BackgroundOocytes are the female gametes which establish the program of life after fertilization. Interactions between oocyte and the surrounding cumulus cells at germinal vesicle (GV) stage are considered essential for proper maturation or ‘programming’ of oocytes, which is crucial for normal fertilization and embryonic development. However, despite its importance, little is known about the molecular events and pathways involved in

Divyaswetha Peddinti; Erdogan Memili; Shane C. Burgess; Jay M. Baltz

2010-01-01

384

Assessment of meiotic spindle configuration and post-warming bovine oocyte viability using polarized light microscopy.  

PubMed

The objectives of this study were to assess the efficiency of polarized light microscopy (PLM) in detecting microtubule-polymerized protein in in vitro-matured bovine oocytes; to examine its effects on oocyte developmental competence; and to assess the meiotic spindle of in vitro-matured oocytes after vitrification/warming and further assessment of oocyte developmental competence. In the first experiment, the presence of microtubule-polymerized protein (MPP) was confirmed as a positive PLM signal detected in 99.1% of analysed oocytes (n = 115), which strongly correlated (r = 1; p < 0.0001) with the presence of MPP as confirmed by immunostaining. In the second experiment, oocytes (n = 651) were exposed or not (controls) to PLM for 10 min and then fertilized and cultured in vitro. Oocytes exposed to PLM did not significantly differ from controls with regard to cleavage, total blastocyst and expanded blastocyst rates and cell numbers. In the third experiment, meiotic spindles were detected in 145 of 182 oocytes (79.6%) following vitrification and warming. Interestingly, after parthenogenetic activation and in vitro culture, oocytes that displayed a positive PLM signal PLM(+) differed significantly from PLM(-) in cleavage and Day 8 blastocyst rates. These results suggest that polarized light microscopy is an efficient system to detect microtubule-polymerized protein in in vitro-matured bovine oocytes and does not exert detrimental effects on bovine oocyte developmental competence. Moreover, PLM could be used as a tool to assess post-warming viability in vitrified bovine oocytes. PMID:23106568

Caamaño, J N; Díez, C; Trigal, B; Muñoz, M; Morató, R; Martín, D; Carrocera, S; Mogas, T; Gómez, E

2012-10-26

385

Effect of Season and Exposure to Heat Stress on Oocyte Competence in Holstein Cows1  

Microsoft Academic Search

Two experiments were conducted to evaluate sea- sonal variation in oocyte competence in Holstein cows and to test whether oocyte quality in summer is af- fected by the magnitude of heat stress. In the first experiment, ovaries of Holstein cows were collected from a slaughterhouse and used to harvest oocytes over 1 yr (n = 18 replicates). After in vitro

Y. M. Al-Katanani; F. F. Paula-Lopes; P. J. Hansen

2002-01-01

386

The Influence of Meiotic Spindle Configuration by Cysteamine during in vitro Maturation of Mouse Oocytes  

Microsoft Academic Search

Background: The aim of this study was to assess effects of cysteamine as an anti-oxidant on rate of in vitro maturation of oocyte and determination of its effects on spindle size and shape. Methods: Pre-mature mice were primed with pregnant mare stimulating gonadotrophin (PMSG) and germinal vesicle (GV) stage oocytes were obtained 48 h after. The oocytes were cultured in

Amaneh Mohammadi Roushandeh; Mehryar Habibi Roudkenar

387

Ascorbic acid effects on in vitro maturation of mouse oocyte with or without cumulus cell  

Microsoft Academic Search

Ascorbic acid has long been associated with fertility. This study was designed to determine the effects of ascorbic acid on in vitro maturation of mouse oocyte with or without cumulus cells. In this study, 508 denuded oocytes (DOs) and 527 cumulus-oocyte complexes (COCs) from mice stimulated with pregnant mare's serum gonadotrophin (PMSG) were incubated for 24 h in medium containing

Behnaz Nadri; Saeed Zeinoaldini; Hamid Kohram

388

EFFECT OF CYSTEAMINE ON THE RATE OF IN VITRO MATURATION OF OOCYTES IN TWO MEDIA  

Microsoft Academic Search

Rate of in vitro maturation of oocytes is one of the challenges of assisted reproductive techniques. In this study we investigated the effects of supplementation of cysteamine on the rate of in vitro maturation of oocytes in two different media. Germinal vesicle oocytes were collected from mouse ovary and cultured in two media (TCM199 and MEME) with 0, 50, 100,

A. Mohammadi-Roushandeh; M. H. Noori-Mooghahi; P. Pasbakhsh; A. Abddvahabi; M. Akbari; A. Shokrgozar; A. Sobhani

389

Comparison between the characteristics of follicular fluid and the developmental competence of bovine oocytes  

Microsoft Academic Search

There are great differences in the developmental competence of oocytes collected from individual cows. Oocytes grow and mature in the follicular fluid (FF). In the present study, characteristics of the FF of each ovary and the developmental competence of enclosed oocytes were investigated, and these data were then compared. A total of 37 pairs of ovaries were collected from beef

H. Iwata; J. Inoue; K. Kimura; T. Kuge; T. Kuwayama; Y. Monji

2006-01-01

390

In vitro induced pinocytotic activity by a juvenile hormone analogue in oocytes of Drosophila melanogaster  

Microsoft Academic Search

Pinocytotic activity has been analyzed in Drosophila oocytes following either in vivo or in vitro exposure to horseradish peroxidase. The enzyme tracer gains access to the yolk spheres only when supplied to the oocyte in vivo. In oocytes cultured in vitro, peroxidase remains restricted to the residual coated vesicles and to the tubular profiles formed in excess in the cortical

Franco Giorgi

1979-01-01

391

Morphological markers of anteroposterior and dorsoventral polarity in developing oocytes of the hymenopteran Cosmoconus meridionator (Ichneumonidae)  

Microsoft Academic Search

The progressive establishment of anteroposterior and dorsoventral polarity in developing oocytes ofCosmoconus meridionator is described. In fully grown oocytes, the asymmetrical (polar) organization is apparent in the localization of the oocyte nucleus (germinal vesicle) and oosome, and in the uneven (graded) distribution of lipid droplets, yolk spheres and specific organelles termed accessory nuclei (AN). The latter structures occur preferentially within

Szezepan M. Bili?ski

1991-01-01

392

Identification of perilipin-2 as a lipid droplet protein regulated in oocytes during maturation.  

PubMed

Lipid droplet proteins regulate the storage and utilisation of intracellular lipids. Evidence is emerging that oocyte lipid utilisation impacts embryo development, but lipid droplet proteins have not been studied in oocytes. The aim of the present study was to characterise the size and localisation of lipid droplets in mouse oocytes during the periovulatory period and to identify lipid droplet proteins as potential biomarkers of oocyte lipid content. Oocyte lipid droplets, visualised using a novel method of staining cumulus-oocyte complexes (COCs) with BODIPY 493/503, were small and diffuse in oocytes of preovulatory COCs, but larger and more centrally located after maturation in response to ovulatory human chorionic gonadotrophin (hCG) in vivo, or FSH + epidermal growth factor in vitro. Lipid droplet proteins perilipin, perilipin-2, cell death-inducing DNA fragmentation factor 45-like effector (CIDE)-A and CIDE-B were detected in the mouse ovary by immunohistochemistry, but only perilipin-2 was associated with lipid droplets in the oocyte. In COCs, perilipin-2 mRNA and protein increased in response to ovulatory hCG. IVM failed to induce perilipin-2 mRNA, yet oocyte lipid content was increased in this context, indicating that perilipin-2 is not necessarily reflective of relative oocyte lipid content. Thus, perilipin-2 is a lipid droplet protein in oocytes and its induction in the COC concurrent with dynamic reorganisation of lipid droplets suggests marked changes in lipid utilisation during oocyte maturation. PMID:20883652

Yang, Xing; Dunning, Kylie R; Wu, Linda L-Y; Hickey, Theresa E; Norman, Robert J; Russell, Darryl L; Liang, Xiaoyan; Robker, Rebecca L

2010-01-01

393

Classification of Developing Oocytes, Ovarian Development and Seasonal Variation in Rana tigerina  

Microsoft Academic Search

Developing oocytes in adult Rana tigerina can be divided into six stages based on size, color and histology. The stage I oocyte (50-350 µm) is characterized by translucent cytoplasm and a smooth nuclear membrane. The major portion of its cytoplasm contains a large quantity of free ribosomes. Cytoplasmic organelles confined to the peripheral part of oocyte include a few mitochondria,

Prapee Sretarugsa; Wattana Weerachatyanukul; Jittipan Chavadej; Prasert Sobhon

2001-01-01

394

Immunocytogenetic detection of normal and abnormal oocytes in human fetal ovarian tissue in culture  

Microsoft Academic Search

This study aimed to: (i) determine whether oocytes are present in cultures of human fetal ovary; (ii) identify whether meiotic anomalies are evident; and (iii) assess whether preparation or culture conditions influence oocyte survival and meiotic progression. Ovaries were collected from fetuses after termination at 13-16 weeks. Oocyte assessment utilized antibodies specific for synaptonemal complex proteins (associated with chromosomes only

G. M. Hartshorne; A. L. Barlow; T. J. Child; D. H. Barlow; M. A. Hulten

1999-01-01

395

Vitrification of oocytes from endangered Mexican gray wolves ( Canis lupus baileyi)  

Microsoft Academic Search

Careful genetic management, including cryopreservation of genetic material, is central to conservation of the endangered Mexican gray wolf. We tested a technique, previously used to vitrify human and domestic animal oocytes, on oocytes from domestic dogs as a model and from the endangered Mexican wolf. This method provided a way to conserve oocytes from genetically valuable older female Mexican wolves

S. Boutelle; K. Lenahan; R. Krisher; K. L. Bauman; C. S. Asa; S. Silber

2011-01-01

396

Mouse primary spermatocytes can complete two meiotic divisions within the oocyte cytoplasm  

Microsoft Academic Search

This study was undertaken to determine whether primary spermatocyte nuclei can complete meiosis after transfer into maturing or mature oocytes and can participate in normal embryogenesis. When injected into maturing mouse oocytes at prometaphase of the first meiotic division, spermatocyte chromosomes became arranged on a first meiotic metaphase (Met-I) spindle. Thus, oocytes contained two sets of Met-I chromosomes. When these

I. Sasagawa; S Kuretake; J J Eppig; R Yanagimachi

1998-01-01

397

In vitro nuclear maturation of bitch oocytes in the presence of polyvinyl-pyrrolidone  

Microsoft Academic Search

The main limitation in producing in vitro dog embryos succesfully is the low oocyte maturation rate to the Metaphase II stage. The objective of this experiment was to compare the rates of nuclear maturation of dog oocytes cultured in Tissue Culture Medium 199 (TCM 199) supplemented with polyvinyl-pirrolidone (PVP) with oocytes cultured in TCM 199 with estrous cow serum (ECS)

L. C. Santos; B. A. Rodrigues; J. L. Rodrigues

398

Mouse Oocyte Mitogenic Activity Is Developmentally Coordinated throughout Folliculogenesis and Meiotic Maturation  

Microsoft Academic Search

Oocytes secrete soluble factors that regulate the growth and differentiation of follicular cells, including maintenance of the distinctive cumulus cell phenotype. This study determines whether the mitogenic activity of oocytes is developmentally regulated and examines the responsiveness of follicular cells to oocytes at different stages of follicular development. Prepubertal SV129 mice of varying ages were primed with 5 IU equine

Robert B. Gilchrist; Lesley J. Ritter; David T. Armstrong

2001-01-01

399

Improved development by Taxol pretreatment after vitrification of in vitro matured porcine oocytes  

Microsoft Academic Search

This study was designed to examine the effect of Taxol pretreatment on vitrification of porcine oocytes matured in vitro by an open pulled straw (OPS) method. In the first experiment, the effect of Taxol pretreatment and fluorescein diacetate (FDA) staining on parthenogenetic development of oocytes was evaluated. In the second experiment, viability, microtubule organiz- ation and embryo development of oocytes

Wen-Qing Shi; Shi-En Zhu; Dong Zhang; Wei-Hua Wang; Guo-Liang Tang; Yun-Peng Hou; Shu-Jun Tian

2006-01-01

400

Derivation of a human blastocyst after heterologous nuclear transfer to donated oocytes  

Microsoft Academic Search

This paper describes the derivation of a blastocyst following heterologous nuclear transfer (NT) into a human oocyte. It also demonstrates that a major obstacle to continuing research in human NT is the availability of suitable human oocytes. In this study, 36 oocytes were donated by 11 women undergoing four different treatments and their developmental potential was evaluated after NT. The

Stojkovic Miodrag; Stojkovic Petra; Leary Christine; Jane Hall Vanessa; Armstrong Lyle; Herbert Mary; Nesbitt Maria; Lako Majlinda; Murdoch Alison

2005-01-01

401

IN VITRO MEIOTIC MATURATION OF MOUSE OOCYTES: ROLE OF NITRIC OXIDE  

Microsoft Academic Search

In this experiment we used cultured mouse cumulus cell-enclosed oocytes (CEOs) and denuded oocytes (DOs) to study the function of nitric oxide (NO) in mouse oocyte meiotic maturation. CEOs and DOs were cultured in a medium containing 4 mM hypoxanthine (HX) to maintain meiotic arrest, in maturation medium (without HX) supplemented with different doses of sodium nitroprusside (SNP, a NO

F. Amidi; M. Abbasi; M. Akbari; E. Sato; A. R. Dehpour; F. Abolhassani

402

Maternal death after oocyte donation at high maternal age: case report  

Microsoft Academic Search

BACKGROUND: The percentage of women giving birth after the age of 35 increased in many western countries. The number of women remaining childless also increased, mostly due to aging oocytes. The method of oocyte donation offers the possibility for infertile older women to become pregnant. Gestation after oocyte-donation-IVF, however, is not without risks for the mother, especially at advanced age.

Joke M Schutte; Nico WE Schuitemaker; Eric AP Steegers; Jos van Roosmalen

2008-01-01

403

Alternative solutions to the current situation of oocyte donation in Singapore  

Microsoft Academic Search

The rising incidence of age-related female infertility in Singapore, coupled with the prohibition on commercialized oocyte donation and egg sharing, has resulted in a severe shortage of donor oocytes. Infertile women are routinely encouraged by fertility doctors here to seek their close relatives and friends as prospective oocyte donors, which does not alleviate the shortage. A number of alternative solutions

Boon Chin Heng

2006-01-01

404

Epigenetic status of the H19 locus in human oocytes following in vitro maturation  

Microsoft Academic Search

Imprinting is an epigenetic modification that is reprogrammed in the germ line and leads to the monoallelic expression of some genes. Imprinting involves DNA methylation. Maternal imprint is reset during oocyte growth and maturation. In vitro maturation (IVM) of oocytes may, therefore, interfere with imprint acquisition and\\/or maintenance. To evaluate if maturing human oocytes in vitro would be hazardous at

Nada Borghol; Jacqueline Lornage; Thierry Blachère; Anne Sophie Garret; Annick Lefèvre

2006-01-01

405

Developmental competence of heifer oocytes selected using the brilliant cresyl blue (BCB) test  

Microsoft Academic Search

The aim of this study was to evaluate the usefulness of the brilliant cresyl blue (BCB) test in the selection of more competent heifer oocytes for in vitro embryo production (IVEP). IVEP from selected BCB heifer oocytes was compared to IVEP from morphologically selected heifer (control group) and cow oocytes. BCB staining determines the activity of glucose-6-phosphate dehydrogenase (G6PD), an

Marc Pujol; Manel López-Béjar; Maria-Teresa Paramio

2004-01-01

406

Selection of prepubertal goat oocytes using the brilliant cresyl blue test  

Microsoft Academic Search

Brilliant cresyl blue stain allows us to determine the activity of glucose-6-phosphate dehydrogenase (G6PD), an enzyme synthesized in growing oocytes but with decreased activity in oocytes that have finished their growth phase. The objective of this study was to evaluate the utility of the brilliant cresyl blue (BCB) test as an indirect measure of oocyte growth, in order to select

E. Rodr??guez-González; M. López-Béjar; E. Velilla; M. T. Paramio

2002-01-01

407

Analysis of the Penetration Resistance of Concrete.  

National Technical Information Service (NTIS)

A combined numerical and analytical study of penetration of concrete by high velocity (approx. 1.8 km/s) projectiles was conducted. The effects of concrete's constitutive modeling on penetration calculations were studied and are discussed. The results of ...

V. M. Gold

1997-01-01

408

Penetrative calcretes and their stratigraphic implications  

NASA Astrophysics Data System (ADS)

Multiple calcrete horizons previously considered representative of true subaerial exposures may, in fact, be false penetrative calcretes related to only one subaerial exposure event. Individual subaerial exposure periods can produce a true surficial calcrete plus a series of penetrative calcretes. Although penetrative calcrete horizons are not laterally traceable over long distances, they are very similar to surficial calcretes, are commonly found at sequence and/or lithologic boundaries (permeability anomalies), and can be easily misinterpreted in core borings as representing individual exposure events. Recent penetrative calcretes are common on elevated limestone ridges of the Caicos Islands where roots penetrate downward, seeking ground-water moisture. In glacial times, penetrative calcretes may have been present throughout carbonate platforms, as ground-water levels were much lower. Penetrative and surficial calcretes can be differentiated by the lower concentrations of insoluble AI and Fe in penetrative calcretes.

Rossinsky, Victor, Jr.; Wanless, Harold R.; Swart, Peter K.

1992-04-01

409

Impact Models for Penetration and Hole Growth.  

National Technical Information Service (NTIS)

Given a hit and specific target, the target's vulnerability depends upon the type of threat, for example, kinetic energy (KE) penetrator, shaped-charge jet or high explosive. This report addresses the threats associated with KE rod penetrators and shaped-...

W. P. Walters J. N. Majerus

1978-01-01

410

Energy-Efficient Penetration of Targets.  

National Technical Information Service (NTIS)

In general, the performance of a kinetic energy (KE) penetrator against most armor targets increases with velocity regardless of the particular penetrator/target interaction mode. It is possible to show that there exists an optimum velocity which maximize...

J. A. Zook K. Frank

1991-01-01

411

Penetration of Projectiles into Seafloor Soils.  

National Technical Information Service (NTIS)

This report presents Laboratory model tests and field tests of a study conducted on projectile penetration into seafloor soils. Existing relationships for predicting penetration behavior are considered, and new relationships are developed to account for o...

D. G. True

1975-01-01

412

Weld penetration and defect control  

SciTech Connect

Highly engineered designs increasingly require the use of improved materials and sophisticated manufacturing techniques. To obtain optimal performance from these engineered products, improved weld properties and joint reliability are a necessarily. This requirement for improved weld performance and reliability has led to the development of high-performance welding systems in which pre-programmed parameters are specified before any welding takes place. These automated systems however lack the ability to compensate for perturbations which arise during the welding process. Hence the need for systems which monitor and control the in-process status of the welding process. This report discusses work carried out on weld penetration indicators and the feasibility of using these indicators for on-line penetration control.

Chin, B.A.

1992-05-15

413

[Transvaginal penetrating fetal head injury].  

PubMed

In utero head traumas are extremely rare and are usually caused by penetrating injuries in the thoracic or abdominal wall that affect the uterine cavity. Transvaginal fetal head injuries have been reported in exceptional cases. This is a case-report of a fetus affected by penetrating head trauma with skull fracture and intra-ventricular hemorrhage after his mother's self-insertion of a blunt object, violently through the vagina. Trauma disrupted the integrity of intrauterine membranes and precipitated preterm labor. After birth, there was a debridement of the scalp and surgical management of the fracture was performed; nevertheless, the patient died four weeks later, due to neonatal sepsis. Management of these wounds must not only be focused on repairing the primary wound, but on preventing the infectious complications. PMID:23070195

Moscote Salazar, Luis Rafael; Alcalá-Cerra, Gabriel; Castellar Leones, Sandra Milena; Gutiérrez Paternina, Juan José

2012-10-01

414

Human oocyte and ovarian tissue cryopreservation and its application  

Microsoft Academic Search

Purpose  To review the recent progress in human oocyte and ovarian tissue cryopreservation, and in the application of these two technologies\\u000a for preserving female fertility of patients who are undergoing cancer treatment.\\u000a \\u000a \\u000a \\u000a Design  The literature on human oocyte and ovarian tissue freezing was searched with PubMed. The scientific background, current developments\\u000a and potential future applications of these two methods were reviewed.\\u000a \\u000a \\u000a \\u000a Results  Chemotherapy

Tao Tao; Alfonso Del Valle

2008-01-01

415

Collection, evaluation, and use of oocytes in equine assisted reproduction.  

PubMed

Assisted reproductive techniques have been developed to obtain pregnancies from subfertile mares and stallions and to salvage gametes after death. In recent years, these procedures have been used for clinical cases with repeated success. Although new developments occur, the basis for the success and future development of assisted reproductive techniques is our ability to collect and handle the equine oocyte successfully. This article focuses on important clinical aspects of oocyte collection and evaluation and briefly discusses the clinical use of assisted reproductive procedures in the horse. PMID:17129807

Carnevale, Elaine M; Maclellan, Lisa J

2006-12-01

416

Dicer is a key player in oocyte maturation  

Microsoft Academic Search

Objective  Apply Dicer siRNA to study functions of Dicer and miRNA during oogenesis.\\u000a \\u000a \\u000a \\u000a Materials and Methods  Mouse oocytes were injected with Dicer siRNA and negative control siRNA and then matured in vitro. After IVM, oocytes were\\u000a examined for maturation rates, spindle and chromosomal organization, and various gene expressions.\\u000a \\u000a \\u000a \\u000a \\u000a Results  Dicer siRNA significantly reduced maturation rates, increased abnormal spindle and chromosomal organization, and reduced

Hung-Ching Liu; YaXu Tang; Zhiying He; Zev Rosenwaks

2010-01-01

417

Lipoprotein mediated lipid uptake in oocytes of polychaetes (Annelida)  

Microsoft Academic Search

The uptake of the 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-labeled sex-unspecific Nereis lipoprotein was investigated in oocytes of the nereidid polychaetes Nereis virens and Platynereis dumerilii. The fluorescence label was first observed in endocytic vesicles (<1 ?m diameter), which later fused to larger vesicles (2–3 ?m);\\u000a these were finally incorporated into existing unlabeled yolk granules (5–6 ?m). In Platynereis oocytes, the fusion of endocytic vesicles was

Sven Schenk; Ulrich Hoeger

2009-01-01

418

Acentrosomal spindle assembly and chromosome segregation during oocyte meiosis.  

PubMed

The ability to reproduce relies in most eukaryotes on specialized cells called gametes. Gametes are formed by the process of meiosis in which, after a single round of replication, two successive cell divisions reduce the ploidy of the genome. Fusion of gametes at fertilization reconstitutes diploidy. In most animal species, chromosome segregation during female meiosis occurs on spindles assembled in the absence of the major microtubule-organizing center, the centrosome. In mammals, oocyte meiosis is error prone and underlies most birth aneuploidies. Here, we review recent work on acentrosomal spindle formation and chromosome alignment/separation during oocyte meiosis in different animal models. PMID:22480579

Dumont, Julien; Desai, Arshad

2012-04-03

419

Acentrosomal Spindle Assembly & Chromosome Segregation During Oocyte Meiosis  

PubMed Central

The ability to reproduce relies in most eukaryotes on specialized cells called gametes. Gametes are formed by the process of meiosis in which, after a single round of replication, two successive cell divisions reduce the ploidy of the genome. Fusion of gametes at fertilization reconstitutes diploidy. In most animal species, chromosome segregation during female meiosis occurs on spindles assembled in the absence of the major microtubule-organizing center, the centrosome. In mammals, oocyte meiosis is error-prone and underlies the majority of birth aneuploidies. Here, we review recent work on acentrosomal spindle formation and chromosome alignment/separation during oocyte meiosis in different animal models.

Dumont, Julien; Desai, Arshad

2012-01-01

420

Artificial intelligence techniques for embryo and oocyte classification.  

PubMed

One of the most relevant aspects in assisted reproduction technology is the possibility of characterizing and identifying the most viable oocytes or embryos. In most cases, embryologists select them by visual examination and their evaluation is totally subjective. Recently, due to the rapid growth in the capacity to extract texture descriptors from a given image, a growing interest has been shown in the use of artificial intelligence methods for embryo or oocyte scoring/selection in IVF programmes. This work concentrates the efforts on the possible prediction of the quality of embryos and oocytes in order to improve the performance of assisted reproduction technology, starting from their images. The artificial intelligence system proposed in this work is based on a set of Levenberg-Marquardt neural networks trained using textural descriptors (the local binary patterns). The proposed system was tested on two data sets of 269 oocytes and 269 corresponding embryos from 104 women and compared with other machine learning methods already proposed in the past for similar classification problems. Although the results are only preliminary, they show an interesting classification performance. This technique may be of particular interest in those countries where legislation restricts embryo selection. One of the most relevant aspects in assisted reproduction technology is the possibility of characterizing and identifying the most viable oocytes or embryos. In most cases, embryologists select them by visual examination and their evaluation is totally subjective. Recently, due to the rapid growth in our capacity to extract texture descriptors from a given image, a growing interest has been shown in the use of artificial intelligence methods for embryo or oocyte scoring/selection in IVF programmes. In this work, we concentrate our efforts on the possible prediction of the quality of embryos and oocytes in order to improve the performance of assisted reproduction technology, starting from their images. The artificial intelligence system proposed in this work is based on a set of Levenberg-Marquardt neural networks trained using textural descriptors (the 'local binary patterns'). The proposed system is tested on two data sets, of 269 oocytes and 269 corresponding embryos from 104 women, and compared with other machine learning methods already proposed in the past for similar classification problems. Although the results are only preliminary, they showed an interesting classification performance. This technique may be of particular interest in those countries where legislation restricts embryo selection. PMID:23177416

Manna, Claudio; Nanni, Loris; Lumini, Alessandra; Pappalardo, Sebastiana

2012-10-02

421

Jeeps Penetrating a Hostile Desert  

ERIC Educational Resources Information Center

|Several jeeps are poised at base camp on the edge of a desert aiming to escort one of them as far as possible into the desert, while the others return to camp. They all have full tanks of gas and share their fuel to maximize penetration. In a friendly desert it is best to leave caches of fuel along the way to help returning jeeps. We solve the…

Bailey, Herb

2009-01-01

422

Bacterial penetration of restored cavities.  

PubMed

The aim of this study was to assess the quality of the marginal seals of 7 restoratives by means of a bacterial penetration test in vitro. Sixty intact premolars and third molars that were scheduled for extraction were used in the test. There were 2 experimental groups of teeth, as follows: (1) A class V conventional cavity and a wedge erosion cavity were prepared on the buccal surface and the lingual surface, respectively, of each tooth. (2) A class V conventional cavity and a wedge erosion cavity were prepared on the buccal surface and the lingual surface, respectively, of each tooth with a completely removed enamel layer. The cavities were then reconstructed with different restorative materials. The quality of the marginal seals was evaluated by submerging the teeth in a bacterial suspension and incubating them in an anaerobic milieu at 37 degrees C for 20 hours. The teeth were subsequently processed for histologic data and bacterial staining. The best marginal sealing in both the wedge erosion and the class V cavities was provided by the Herculite/Optibond system and the Valux Plus/Scotchbond Multipurpose system. Bacterial penetration was slightly greater with the Luxat compomer and the Dyrect compomer, as well as with Vitremer glass ionomer cement and Fuji LC glass ionomer cement. The bacterial penetration test showed that the use of restorative material does not entirely eliminate microleakage. PMID:11250635

Zivkovi?, S; Bojovi?, S; Pavlica, D

2001-03-01

423

DOSE RESPONSE OF ELASTASE-INDUCED EMPHYSEMA IN HAMSTERS  

EPA Science Inventory

Elastase-induced emhysema in hamsters was studied using pulmonary function tests in an effort to develop techniques for determining the effects of air pollutants on the progression of this disease. It appears that as little as 6 units of elastase produces mild emphysema in hamste...

424

Relationship between Autonomic and Behavioral Thermoregulation in the Golden Hamster.  

National Technical Information Service (NTIS)

Preferred ambient temperature (Ta) of male golden hamsters (Mesocricitus auratus) was measured repeatedly by placing the animals in a temperature gradient for 80 min. A total of 180 observations were made during the last 20 min of treatment in the gradien...

C. J. Gordon K. S. Fehlner M. D. Long

1986-01-01

425

Clozapine chronically suppresses alcohol drinking in Syrian golden hamsters  

Microsoft Academic Search

Alcohol use disorder is common in patients with schizophrenia and is associated with poor clinical outcomes. Preliminary reports from our group and others suggest that the atypical antipsychotic clozapine may decrease alcohol use in these patients. We have previously shown that clozapine suppresses alcohol consumption for 9 days in Syrian golden hamsters. Here, we assessed the effects of clozapine on

David T. Chau; Danielle Gulick; Haiyi Xie; Ree Dawson; Alan I. Green

2010-01-01

426

BIODYNAMIC STUDIES OF HAMSTER FLANK ORGAN GROWTH: HORMONAL INFLUENCES  

Microsoft Academic Search

The biodynamic response of flank organs of male and female hamsters to androgenic stimulation has been studied by autoradiographic and electron microscopic techniques, as well as by routine histology and gross observation. Intraperitoneal administration of 2.5 mg of testosterone on alternate days resulted in bilateral increase in palpable bulk, and pigmentation of flank organs of females, males, and castrated males.

Phillip Frost; Joseph L. Giegel; Gerald D. Weinstein; Edward C. Gomez

1973-01-01

427

Sequence of centromere separation of mitotic chromosomes in Chinese hamster  

Microsoft Academic Search

Chromosome preparations in late metaphase cells from bone marrow of colcemid treated male Chinese hamsters were used to analyse the sequence of separation of sister centromeres. Chromatids of chromosomes 2 and 1 are the first ones to separate at centromeres, followed by members of group B, D and C. Some acrocentric chromosome is always the last one to separate at

Baldev K. Vig; Herbert G. Miltenburger

1976-01-01

428

EST sequencing for gene discovery in Chinese hamster ovary cells  

Microsoft Academic Search

Chinese hamster ovary (CHO) cells are one of the most important cell lines in biological research, and are the most widely used host for industrial production of recombinant therapeutic proteins. Despite their extensive applications, little sequence information is available for molecular based research. To facilitate gene discovery and genetic engineering, two cDNA libraries were con- structed from three CHO cell

Katie Fraass Wlaschin; Peter Morin Nissom; Marcela de Leon Gatti; Peh Fern Ong; Sanny Arleen; Kher Shing Tan; Anette Rink; Breana Cham; Kathy Wong; Miranda Yap; Wei-Shou Hu

2005-01-01

429

Hamster Wheel: A Multidiscipline Educational and Race Toy  

Microsoft Academic Search

This paper introduces a novel and tangible educational or race toy, called Hamster Wheel, which is an approach and interface to illustrate multidiscipline science and technology in an intuitive and economic fashion, and encourage any age's people to explore science. The multidiscipline to be learnt through this toy includes kinematics, control engineering, discrete mathematics, computer and mechanical engineering. Through the

Jianping Zhou

430

Analysis of polysaccharide taste in hamsters: Behavioral and neural studies  

Microsoft Academic Search

A series of studies was carried out in hamsters (Mesocricetus auratus) to determine whether polysaccharides have behavioral and neurophysiological characteristics that distinguish them from simple sugars. Behavioral studies utilized solutions of glucose, maltose, sucrose, Polycose, and glycogen in two-bottle preference tests and in tests of generalization of conditioned taste aversions. Multiunit and single-unit responses of the chorda tympani nerve were

Bradley G. Rehnberg; Bruce I. MacKinnon; Thomas P. Hettinger; Marion E. Frank

1996-01-01

431

CARCINOGENIC POTENTIAL OF ROTENONE. PHASE I: DIETARY ADMINISTRATION TO HAMSTERS  

EPA Science Inventory

Studies were performed to evaluate the potential carcinogenicity rotenone in the Syrian Golden hamster. Several ancillary range-finding studies were carried out including 14-day feeding trials and a reproduction experiment. The latter experiment indicated that rotenone at a level...

432

Development of Taenia pisiformis in golden hamster (Mesocricetus auratus)  

PubMed Central

The life cycle of Taenia pisiformis includes canines as definitive hosts and rabbits as intermediate ho