bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of follicle‐stimulating hormone and ovarian steroids during vitro meiotic maturation on fertilization of rat oocytes
Authors: Zhang X. , Armstrong D. T. 
Published: February 2005

AbstractThe present study examined the effects of gonadotropins and ovarian steroids during in vitro meiotic maturation of rat oocytes on their ability to undergo in vitro fertilization. Fully grown oocytes were isolated from antral follicles of immature rats and cultured as oocyte‐cumulus cell complexes (OCC) under conditions in which completion of meiotic maturation occurs spontaneously. They were then exposed to spermatozoa under conditions in which oocytes matured in vivo exhibit high fertilization rates. Compared with oocytes from pregnant mare's serum gonadotropin (PMSG) or follicle‐stimulating hormone (FSH)‐treated rats, a simiiar proportion of the oocytes (>80%) from untreated rats underwent germinal vesicle breakdown, but such oocytes had a lower rate of fertilization (70% vs. 20%). The presence of FSH during in vitro maturation restored the fertilization rate for oocytes from untreated rats, while a cytochrome P450 inhibitor, aminoglutethimide phosphate abolished this beneficial effect of FSH. The addition of progesterone during the in vitro maturation period duplicated the beneficial effect of FSH on fertilization rate of oocytes from untreated rats; oestradiol‐17β was less effective in this regard, and 5α‐dihydrotestosterone was ineffective. These findings indicate that FSH and progesterone, although having no apparent effect on nuclear maturation of the oocyte, play an important role during oocyte maturation in enabling normal fertilization to occur.
Microtubule assembly is required for the formation of the pronuclei, nuclear lamin acquisition, and DNA synthesis during mouse, but not sea urchin, fertillization
Authors: Schatten Heide , Simerly Calvin , Maul Gerd , Schatten Gerald 
Published: February 2005

AbstractMicrotubule assembly is required for the formation of the male and female pronuclei during mouse, but not sea urchin, fertilization. In mouse oocytes, 50 μM colcemid prevents the decondensation of the maternal meiotic chromosomes and of the incorporated sperm nucleus during in vitro fertilization. Nuclear lamins do not associate with either of the parental chromatin sets although peripherin, the PI nuclear peripheral antigen, appears on both. DN A synthesis docs not occur in these fertilized, colcemid‐arrested oocytes. This effect is limited to the first hours after ovulation, since colcemid added 4–6 hours later no longer prevents pronuclear development, lamin acquisition, or DNA synthesis. Neither microtubule stabilization with 10 μM taxol nor microfilament inhibition with 10 μM cytochalasin D or 2.2 μg/ml lalrunculin A prevent these pronuclear events; these drugs will inhibit the apposition of the pronuclei at the egg center. In sea urchin eggs, colcemid or griseofulvin treatment doe? not result in the same effect and the male pronucleus forms with the attendant accumulation of the nuclear lamins. The differences in the requirement for microtubule assembly during pronucleus formation may be related to the cell cycle: In mice the sperm enters a meiotic cytoplasm, whereas in sea urchin eggs it enters an interphase cytoplasm. Refertilization of mitotic sea urchin eggs was performed to test the possibility that this phenomenon is related to whether the sperm enters a meiotic/mitotic cytoplasm or one at interphase; during refertilization at first mitosis, the incorporated sperm nucleus is unable to decondense and acquire lamins. These results indicate a requirement for microtubule assembly for the progression from meiosis to first interphase during mouse fertilization and suggest that the cytoskeleton is required for changes in nuclear architecture necessary during fertilization and the cell cycle.
Changes in the distribution of intramembranous particles and filipin‐reactive membrane sterols during in vitro capacitation of golden hamster spermatozoa
Authors: Suzuki Fumie , Yanagimachi Ryuzo 
Published: February 2005

AbstractMembrane alterations accompanying in vitro capacitation of hamster spermatozoa were examined using the freeze‐fracture technique with or without use of filipin, a sterol‐binding probe. In the spermatozoa prior to or at 10 min after start of incubation in capacitating medium, large (about 11 nm) and small (8–9 nm) intramembranous particles (IMPs) were present in the periacrosomal region of the sperm plasma membrane (PAPM). Filipin sterol complexes (FSCs) were densely (about 500/μ2) distributed in the PAPM prior to incubation. The density of FSCs in the PAPM was reduced by 70–80% of the original density by 2 hr of incubation. At the same time, small patches of IMP‐free areas appeared in the plasma membrane above the equatorial and middle segments of the acrosome. By the end of 3 hr of incubation, the majority of small IMPs had disappeared from the PAPM. Remaining large and small IMPs tended to aggregate in the PAPM. During incubation in capacitation medium, “cords,” or linear arrangements of closely packed IMPs, appeared near the posterior ring of the sperm head. These observations strongly suggest that the acrosome reaction of the hamster spermatozoa is preceded by the removal (deletion) of filipin‐reactive sterols (FRSs) and the disappearance of small IMPs from the lipid bilayer of PAPM.
Effect of follicle‐stimulating hormone on metabolism and maturation in Bufo arenarum oocytes
Authors: de Atenor Maria S. Budeguer , de Legname Hortensia Salomón , Legname Arnaldo H. 
Published: February 2005

AbstractIn the fully grown Bufo arenarum oocyte, carbohydrate breakdown during the autumn‐winter season is accomplished mainly through the glycolytic pathway followed by the krebs cycle. During the breeding season (spring‐summer), carbohydrates are used mainly through the pentose phosphate cycle and through the variant of the Krebs cycle known as the glutamic aspartic cycle.The metabolism operating in the oocytes was determined using the following paramenters: 1) the capacity of isolated mitochondria to oxidize citrate and fumarate; 2) the enzymatic activities of phosphofructokinase (PEK) and glucose‐6‐phosphate dehydrogenase (G‐6‐PDH); and 3) cirate and ATP compartmentalization.The present paper shows that follicle‐stimulating hormone (FSH) would be one of the factors responsible for summer metabolism, since ovary fractios obtained from winter specimens treated with the hormone acquired the metabolic characteristics corresponding to oocytes obtained from breeding‐season animals from dose‐response, and response in the function of time curves, it could be assumed that the optimum doses and times were 0.1 μg FSH/ml of incubation medium and 30 min treatment, respecitively.The metabolic effect of FSH upon oocytes could be mediaated by the adenylate cyclase cAMP system, since treatment of ovric fractions with cAMP 10‐3 M reproduced the effects obtained with the hormone. In addition, 0.02 mg/ml tetracyline proved to block the effect of FSH. A direct metabolic action of FSH on body cavity oocytes (without follicle cells) was observed when submitting these oocytes to the same hormonal treatment.
X‐Y chromosome dissociation in mouse strains difering in efficiency of spermatogenesis: Elevated frequency of univalents in pubertal males
Authors: Krzanowska Halina 
Published: February 2005

AbstractDissociation of the X‐Y chromosome bivalent in diakinesis‐metaphase I spermatocytes of adult mice was significantly more frequent in the CBA strain (29%) than in C57, KP, or KE strains (7–11%). Autosome dissociatio (1–5%) involved only the smallest chromosome pairs. Eleyatedfrequency of X‐Y dissociation in the CBA strain correlates with significantly lower testes weight and lower yield of spermatogenesis, which suggests that sex bivalent dissociation man be responsible for some loss of spermatogenic cells. However, sperm quality is not affected, the percentage of normal spermatozoa and their fertlizing capacity being higher in CBA thatn in the remaining strains. Two congenic strains, KE and KE. CBA (the latter with the Y chromosome introduced from CBA), had the same level of X‐Y dissociatios, suggesting that the Y chromosome plays no rle in the determination of this character. In comparison with adult males pubertal (27–29 day‐old) males had twice as hig a frequency of X‐Y dissociation in KE an KP strains, and combined frequeicies of dissociated sex and autosome bivalents were significantly higher in pubertal males of all tested strains. Although te level of chromosome dissociation is not sufficient to explain increased mortality of germ cells observed in pubertal males, it could be one of the contributing factors.
Effects of glutathione (GSH and GSSG) and glutathione reductase (GR) on zona‐free hamster oocyte ability to decondense human sperm
Authors: Lassalle B. , Testart J. 
Published: February 2005

AbstractEffects of reduced glutathione (GSH), oxidized glutathione (GSSG), or glutathione reductasc (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 10IU/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.
Motility and fertilizing ability of rat epididymal spermatozoa washed by a continuous gradient of percoll
Authors: Miyake M. , Coney P. , Iritani A. , Kling O. R. 
Published: February 2005

AbstractRemoval of epididymal fluids from epididymal sperm suspension is an important step for the study of sperm motility, capacitation, and the acrosome reaction. The technique of washing should minimize damage to viable spermatozoa but at the same time efficiently remove debris, non‐sperm cells, and biological fluids. We examined sperm motility and fertilizability in vitro of rat epididymal spermatozoa after washing with Percoll continuous gradient. Nine milliliters (ml) of 50%N‐2‐hydroxyethylpiperazine‐N1‐2‐ethanesulfonicacid (HEPES) buffered Percoll solution was centrifuged at 20,000g for 45 minutes to form a continuous gradient. One hundred to 300μ of sperm suspension was loaded onto the surface of the gradient and centrifuged at 150 g and 1,500 g for 10 minutes. Two main layers of spermatozoa were formed, one of high (lower layer) and one of low (upper layer) motility. At centrifugation 1,500g, the sperm density and motility in the lower layer were greater than at 150g.Spermatozoa from both layers at 150g and l,500g were diluted with modified Krebs‐Ringer's bicarbonate solution (mKRB) and preincubated for 5 hours. Superovulated eggs collected from 21–25‐day‐old Wistar strain immature rats were introduced into the preincubated sperm suspension for insemination and fixed 5‐5.5 hours later for observation of fertilization. Spermatozoa from both layers, 150g and 1,500 g, showed the same fertilizability in vitro as control spermatozoa. From these results we conclude that Percoll gradients can be used for washing rat epididymal sperm for the study of sperm physiology including fertilization.
Lipid peroxidation in human spermatozoa as relatd to midpiece abnormalities and motility
Authors: Rao B. , Soufir J. C. , Martin M. , David G. 
Published: February 2005

AbstractThe formation of malondialdehyde (MDA), a product of lipid peroxidation (LPO), was measured in human spermatozoa from 27 subjects with normal sperm characteristics. Peroxidation of lipids in washed spermatozoa was induced by catalytic amounts of ferrous ions and ascorbate and malondiaidehyde dctermint‐d by thiobarbituric method. MDA formation varied considerably from one sample to another. The studied population showed a strong correlation between lipid peroxidation potential (amount of MDA formed by 108 spermatozoa after 1 hour of incubation) and 1) initial motility r = −0.623, P = 0.001; and 2) morphologic abnormalities of the midpiece r = 0.405, P = 0.05. These results suggest that poor motility is linked with membrane fragility and that spermatozoa with midpiece abnormalities probably have membrane and/or cytoplasmic antiperoxidant system defects. Because LPO potential is related to the two most important characteristics of fertility, it seems possible that it has the potential to become a good biochemical index of semen quality.
Effect of the degree of maturation of mouse oocytes at fertilization: A source of chromosome imbalance
Authors: Badenas J. , Santaló J. , Calafell J. M. , Estop A. M. , Egozcue J. 
Published: February 2005

AbstractIt has been suggested that the abnormal maturation of the human oocyte during fertilization in vitro may result in chromosome imbalance and, induce embryonic loss. Using a mouse model, we have studied the influence of the degree of oocyte maturation (either immaturity or overmaturity) on the chromosome characteristics of embryos at the first‐cleavage division. Immature oocytes were obtained 2–3 h or 3–4 h before the expected ovulation time (b.o.). Overmaturation was induced by aging the newly ovulated oocytes in vitro for 3,6, and 12 h. Our results show a significant decrease in the fertilization rate in the immature groups (65.53% at 2–3 h b.o. and 16.59% at 3–4 h b.o. vs. 78.22% at control) and after 12 h of in vitro aging (69.39%), while a significant increase of this parameter was found at 3 h of aging (82.59%) as compared to the other groups. No significant differences were found in the occurrence of aneup'.oidy or hypcrhaploidy in embryos obtained from immature, newly ovulated, and overmature oocytes. Finally, an increased incidence of polyploidy was detected in immature, 2–3 h b.o. (31.20%), and overmature, 3 h (23.04%) and 6 h (31.61%), groups as compared to the control group (14.59%).
The plasama membrane of Xenopus laevis spermatozoon
Authors: Bernardini Giovanni , Zanmarchi Gemma , Belgiojoso Pio 
Published: February 2005

AbstractXenopus laevis sperm plasma membrane ultrastructure has been studied by means of freeze‐fracture, deep‐etching, and lectin‐gold binding. Xenopus spermatozoa differ from those of other species in that their plasma membrane does not exhibit topographical domains. In fact, no geometric arrangement or characteristic array of particles is present on fractured plasma membrane. Fractures rarely occur in acrosomal or nuclear membranes. Wheat germ agglutinin receptors are distributed homogeneously, on the plasma membrane of the sperm head and tail.
Complex spermatozoon of the live‐bearing half‐beak, Hemirhamphodon pogonognathus (Bleeker): Ultrastructural description (Euteleostei, Atherinomorpha, Beloniformes)
Authors: Jamieson B. G. M. 
Published: February 2005

AbstractThe spermatozoon of Hemirhamphodon pogonognalhus shows modifications that are frequent though not obligate in internally fertilizing sperm, notably elongation of the nucleus and extension of the mitochondria of the midpiece as an elongate sheath around the proximal region of the axoneme. These similarities to poecilid and jenynsid sperm are considered homoplasic. As in the mature sperm of all but one investigated teleost, an acrosome is absent. The elongate, blade‐shaped, electron‐dense nucleus has a mean length of 3.2 μm; its basal implantation fossa, less than one‐tenth of the length of the nucleus, houses the anterior half of the distal and only centriole (of triplet construction with satellite rays), a centriolar plug, and a mass connecting the centriole to the wall of the fossa. A unilateral putative centriole adjunct is present. The anterior region of the axoneme is surrounded by a mitochondrial sleeve, and internal to this, separated by a cisterna, by a submitochondrial sleeve. The mitochondrial sleeve unites posteriorly with the submitochondrial sleeve. Between the submitochondrial sleeve and the axoneme is a space, the cytoplasmic canal, that is open to the exterior posteriorly. The discrete, cristate mitochondria, in their sleeve, are unique in investigated atherinomorph sperm in being bilateral, grouped on only two opposing sides of the axoneme, with an arc‐shaped ‘intermitochondrial link’ between. The 9 + 2 flagellum is unique for the Animalia in having 23 radial subplasmalemmal rods, repeated longitudinally (periodicity 0.025 pm) in a quasicrystalline array. Internal fertilization is deduced to have arisen in the Exocoetoidei independently of that in the Cyprinidcntiformes.
Ultrasound‐guided transfundal uterine sperm recovery from Macaca fascicularis
Authors: VandeVoort Catherine A. , Tollner Theodore L. , Tarantal Alice F. , Overstreet James W. 
Published: February 2005

AbstractPrevious studies from this center have indicated that the cynomolgus macaque (Macaca fascicularis) may serve as a model for human sperm interaction with the cervix and uterus. In some macaque species, transcervical aspiration of the uterine contents carries a significant risk of disturbing the cervical milieu due to the serpentine nature of the cervix. The only alternatives have been surgical procedures such as laparotomy or laparoscopy. In this paper, we report our experience with a new technique for ultrasound‐guided sampling of spermatozoa in the macaque uterus. Twenty adult female cynomolgus macaques were monitored for menses (first day of menses = day l), and one mating per cycle was allowed on day 10, 11, or 12. In one group of ten animals, cervical mucus was sampled at 3 or 18 hr postcoitus (pc) and ultrasound‐guided uterine aspiration was performed at 24 hours pc. In a second group of ten monkeys, uterine aspiration was at six hr pc and sperm numbers and motility were counted in the uterine fluid. Uterine fluid was obtained from fourteen of twenty monkeys. Pregnancy occurred in ten of the twenty experimental cycles. Ultrasound‐guided uterine aspiration appears to be a reliable method for the evaluation of sperm transport in female macaques. The correlations between uterine sperm recovery and cervical mucus sperm populations arc discussed. The high conception rate in treatment cycles indicates that this procedure can be performed without apparent risk to pregnancy.
Fabrication of Nanoscale Rings, Dots, and Rods by Combining Shadow Nanosphere Lithography and Annealed Polystyrene Nanosphere Masks
Authors: Kosiorek Adam , Kandulski Witold , Glaczynska Hanna , Giersig Michael 
Published: February 2005

AbstractThe application of shadow nanosphere lithography for the preparation of large‐area, two‐dimensional, metallic nanostructures of different shape is described. Through changing the mask morphology by temperature processing and varying the evaporation conditions, particles with morphologies such as rings, rods, and dots have been produced. This process allows outstanding control of the size and morphology of the particles. The efficient technique is shown to scale down the size of metallic nanoparticles from 200 to 30 nm, while preserving the original nanosphere spacing and order. The 150‐nm‐diameter Fe rings produced by this method show ferromagnetic behavior, which was predicted by theoretical simulation. All the experimental results were confirmed by computer simulations, which also showed the possibility of creating periodic arrays of any other geometrical shape.
Increased nuchal translucency and distended jugular lymphatic sacs on first‐trimester ultrasound
Authors: Bekker M. N. , Haak M. C. , Rekoert‐Hollander M. , Twisk J. , Van Vugt J. M. G. 
Published: February 2005

AbstractObjectiveTo investigate the presence and volume of jugular lymphatic sacs (JLS) in first‐trimester fetuses with normal nuchal translucency thickness (NT) and in those with increased NT.MethodsThis was a prospective study of 26 fetuses with NT > 95th percentile, which were compared with 137 fetuses with normal NT. Following crown–rump length (CRL) and NT measurement the neck region of the fetus was studied by transvaginal ultrasound. The JLS presented as spheroidal translucencies in the anterolateral region of the neck.ResultsThe prevalence of JLS differed significantly between fetuses with enlarged NT and the control group (P < 0.0001). In the group of 26 fetuses with increased NT, 22 had clearly visible JLS. Chorionic villus sampling revealed aneuploidy in 10 and euploidy in 16 fetuses. In the control group two fetuses, with NT values of 2.8 mm and 2.9 mm, had JLS; pregnancy outcome was normal in both cases. Logistic regression analysis in the total study group showed that an increase in NT was associated with a greater probability of JLS being present (for NT = 3–3.5 mm, probability = 0.67; for NT > 3.5 mm, probability = 0.93). In fetuses with JLS, an increase in CRL was associated with a significant increase in right JLS volume (r = 0.51; P‐value = 0.01) and a non‐significant increase in left sac volume (r = 0.40; P‐value = 0.09). Increase in NT was not associated with a significant increase in JLS volume.ConclusionThere is a significant association between increased NT and the presence of JLS on first‐trimester ultrasound. In our opinion, the pathophysiological explanation for increased NT lies in a disturbance in lymphangiogenesis. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Safety and progress of recursive procedures
Authors: Hesselink Wim H. 
Published: February 2005

Abstract
Temporal weakest precondions are introduced for calculational reasoning about the states encountered during execution of not-necessarily terminating recursive procedures. The formalism can distinguish error from useful nontermination. The precondition functions are constructed in a new and more elegant way. Healthiness laws are discussed briefly. Proof rules are introduced that enable calculational proofs of various safety and progress properties. The construction of the precondition functions is justified in an Appendix that provides the operational semantics.
A logic for Miranda, revisited
Authors: Thompson Simon 
Published: February 2005

Abstract
This paper expands upon work begun in [Tho89], in building a logic for the Miranda functional programming language. After summarising the work in that paper, a translation of Miranda definitions into logical formulas is presented, and illustrated by means of examples. This work expands upon [Tho89] in giving a complete treatment of sequences of equations, and by examining how to translate the local definitions introduced by where clauses.
The status of the logic is then examined, and it is argued that the logic extends a natural operational semantics of Miranda, given by the translations of definitions into conditional equations.
Finally it is shown how the logic can be implemented in the Isabelle proof tool.
Recursion induction for real-time processes
Authors: Davies Jim , Schneider Steve 
Published: February 2005

Abstract
The theory of timed Communicating Sequential Processes is a mathematical approach to the design and analysis of timed distributed systems. This paper extends the language of timed CSP to include a general treatment of recursion. A semantics for mutual recursion is introduced, together with a sufficient condition for the necessary fixpoint to be unique. The resulting language has the familiar unwinding property of process algebra, and exhibits a number of useful algebraic identities. A theory of recursion induction is formulated, and a simple example is presented to illustrate its use.