507 research outputs found

    DNA topoisomerase II enzyme activity appears in mouse sperm heads after fertilization

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    Sperm suspensions of 4 male mice (A, B, C and D), having an initial motility grade of 3.5 were used to examine the presence of DNA topoisomerase II (top 2) activity in sperm heads. The initial percentage motile of male A was 75%, male B was 80%, male C was 70% and male D was 60%. Top 2 activity was examined by testing the effect of etoposide (ETO), a specific top 2 blocker, on sperm motility, fertilizing ability and formation of the male pronuclei. Sperm suspension drops (0.5 ml) and fertilization drops (0.4 ml) were made from TYH medium with 50 μg/ ml ETO (treatments) or TYH without ETO (controls). Sperm suspensions were made from epididymal sperms of the above males in treatments and controls and incubated for 3 h. Mature mouse oocytes (n = 461) were co-cultured with capacitated sperms in the treatments fertilization drops for 5 h. Other oocytes (n= 437) were co-cultured with capacitated sperms in the controls fertilization drops. The oocytes were further cultured for 24 h in KSOM with ETO (for treatments) and KSOM without ETO (for controls). Six sperm motility indexes (SMI) for each male were recorded at 30 min interval according to the formula, SMI = (grade)2 × % motile. The fertilization rates and nuclear events were assessed by observing the pronuclei under an inverted microscope and finding the sperm heads in whole mounts from the oocytes that failed to make pronuclei. The SMI of the treatments and the controls increased gradually and reached peak values after 2 h of incubation. No differences (p > 0.05) were observed among SMI of the treatments and the controls. However, treatment reduced (p < 0.05) the fertilization rate and completely inhibited the formation of the pronuclei. All the oocytes fertilized in treatments (n = 412) failed to form pronuclei and all had enlarged or decondensed sperm heads, whereas 92.6% of the oocytes fertilized in the controls (n= 378) had pronuclei and only 30 (7.4%) oocytes had enlarged or decondensed sperm heads. Neither sperm motility nor fertilization were inhibited with ETO. However, the formation of the pronuclei was blocked. It was concluded that ETO has no effect on sperm capacitation and top 2 activity appears in mouse sperm heads after oocyte penetration.Key words: DNA topoisomerase II, sperm, treatment, mice

    Amortised learning by wake-sleep

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    Models that employ latent variables to capture structure in observed data lie at the heart of many current unsupervised learning algorithms, but exact maximum-likelihood learning for powerful and flexible latent-variable models is almost always intractable. Thus, state-of-the-art approaches either abandon the maximum-likelihood framework entirely, or else rely on a variety of variational approximations to the posterior distribution over the latents. Here, we propose an alternative approach that we call amortised learning. Rather than computing an approximation to the posterior over latents, we use a wake-sleep Monte-Carlo strategy to learn a function that directly estimates the maximum-likelihood parameter updates. Amortised learning is possible whenever samples of latents and observations can be simulated from the generative model, treating the model as a “black box”. We demonstrate its effectiveness on a wide range of complex models, including those with latents that are discrete or supported on non-Euclidean spaces

    Relationship of Glucose Variability and Daily Lifestyle by Continuous Glucose Monitoring (CGM)

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    Authors and collaborators have continued diabetic practice and research on low carbohydrate diet (LCD), continuous glucose monitoring (CGM), and so on. The case is a 64-year-old male with type 2 diabetes mellitus (T2DM) treated with multiple daily insulin injections (MDI). When his HbA1c was 8.2% before, he changed to take tofu instead of rice and bread. HbA1c decreased to 7.1% and 4kg of weight reduction in 2 months. Tofu is a traditional Japanese food made from soybeans, which is a suitable LCD with Protein:Fat:Carbohydrate (PFC) ratio=40:45:15 in this case. His HbA1c is recently unstable, then glucose variability was investigated by CGM using FreeStyle Libre. The glucose pattern was different due to his lifestyle, including working day, off day, playing golf, respectively. The average glucose was 143-167 mg/dL and the estimated HbA1c was 7.1%, whereas HbA1c in outclinic was 8.1%, respectively. This report will hopefully become reference data for future research

    Observation of thundercloud-related gamma rays and neutrons in Tibet

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    During the 2010 rainy season in Yangbajing (4300 m above sea level) in Tibet, China, a long-duration count enhancement associated with thunderclouds was detected by a solar-neutron telescope and neutron monitors installed at the Yangbajing Comic Ray Observatory. The event, lasting for ∼40  min, was observed on July 22, 2010. The solar-neutron telescope detected significant γ-ray signals with energies >40  MeV in the event. Such a prolonged high-energy event has never been observed in association with thunderclouds, clearly suggesting that electron acceleration lasts for 40 min in thunderclouds. In addition, Monte Carlo simulations showed that >10  MeV γ rays largely contribute to the neutron monitor signals, while >1  keV neutrons produced via a photonuclear reaction contribute relatively less to the signals. This result suggests that enhancements of neutron monitors during thunderstorms are not necessarily clear evidence for neutron production, as previously thought

    Prenatal muscle development in a mouse model for the secondary dystroglycanopathies

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    The defective glycosylation of α-dystroglycan is associated with a group of muscular dystrophies that are collectively referred to as the secondary dystroglycanopathies. Mutations in the gene encoding fukutin-related protein (FKRP) are one of the most common causes of secondary dystroglycanopathy in the UK and are associated with a wide spectrum of disease. Whilst central nervous system involvement has a prenatal onset, no studies have addressed prenatal muscle development in any of the mouse models for this group of diseases. In view of the pivotal role of α-dystroglycan in early basement membrane formation, we sought to determine if the muscle formation was altered in a mouse model of FKRP-related dystrophy

    Usefulness of Microcatheters Inserted Overnight for Additional Injection of Sclerosant after Initial Balloon-Occluded Retrograde Transvenous Obliteration of Gastric Varices

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    In patients with large gastric varices, dose limitation of the sclerosant can cause difficulties in achieving complete thrombosis of varices during a single balloon-occluded retrograde transvenous obliteration (BRTO) procedure. For patients with incomplete variceal thrombosis after the first BRTO, additional sclerosant must be injected in a second BRTO. We report a successful case of BRTO for large gastric varices in whom additional sclerosant was injected through a microcatheter that remained inserted overnight. To achieve complete variceal thrombosis in a patient with incomplete thrombosis of large gastric varices after a first BRTO, a retained microcatheter can be used to inject additional sclerosant in a second BRTO the next day
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