6,245 research outputs found
Involvement of sperm acetylated histones and the nuclear isoform of Glutathione peroxidase 4 in fertilization
We previously demonstrated that the nuclear form of Glutathione peroxidase 4 (nGPx4) has a peculiar distribution in sperm head, being localized to nuclear matrix and acrosome and that sperm lacking nGPx4 are more prone to decondensation in vitro. In this study we have hypothesized that sperm retained acetylated histones and nGPx4 are implicated in paternal chromatin decondensation and male pronucleus formation at fertilization. Indeed, significant higher amounts of acetylated histone H4 and acetylated histone H3 were observed by both immunofluorescence and western blotting in nGPx4-KO sperm vs WT ones. In vitro fertilization of zona pellucida- deprived oocytes by WT sperm in the presence of trichostatin (TSA) also demonstrated that paternal histone acetylation was inversely related to the timing of sperm nucleus decondensation at fertilization. In contrast, TSA had no effect on nGPx4-KO sperm, indicating they had a maximal level of histone acetylation. Moreover the paternally imprinted gene Igf2/H19 was hypomethylated in KO sperm compared to WT ones. The lack of nGPx4 negatively affected male fertility, causing a marked decrease in total pups and pregnancies with delivery, a significant reduction in pronuclei (PN) embryos in in vitro fertilization assays and an approximately 2 h delay in egg fertilization in vivo. Because the zona pellucida binding and fusion to oolemma of nGPx4-KO and WT sperm were similar, the subfertility of nGPx4 sperm reflected a decreased sperm progression through egg cumulus/zona pellucida, pinpointing a defective acrosome in line with acrosomal nGPx4 localization. We conclude that paternal acetylated histones and acrosomal nGPx4 are directly involved in fertilization
The distance to the C component of I Zw 18 and its star formation history: A probabilistic approach
We analyzed the resolved stellar population of the C component of the
extremely metal-poor dwarf galaxy Izw18 in order to evaluate its distance and
star formation history as accurately as possible. In particular, we aimed at
answering the question of whether this stellar population is young. We
developed a probabilistic approach to analyzing high-quality photometric data
obtained with the Advanced Camera for Surveys of the Hubble Space Telescope.
This approach gives a detailed account of the various stochastic aspects of
star formation. We carried out two successive models of the stellar population
of interest, paying attention to how our assumptions could affect the results.
We found a distance to the C component of I Zw 18 as high as 27 Mpc, a
significantly higher value than those cited in previous works. The star
formation history we inferred from the observational data shows various
interesting features: a strong starburst that lasted for about 15 Myr, a more
moderate one that occurred approx 100 Myr ago, a continuous process of star
formation between both starbursts, and a possible episode of low level star
formation at ages over 100 Myr. The stellar population studied is likely approx
125 Myr old, although ages of a few Gyr cannot be ruled out. Furthermore,
nearly all the stars were formed in the last few hundreds of Myr.Comment: 13 pags., 17 (low-resolution) Figs. Accepted by A&
Influence of the flow on the anchoring of nematic liquid crystals on a Langmuir-Blodgett monolayer studied by optical second-harmonic generation
The influence of capillary flow on the alignment of the nematic liquid
crystal MBBA on fatty acid Langmuir-Blodgett monolayers was studied by optical
second-harmonic generation. The surface dipole sensitivity of the technique
allows probing the orientation of the first liquid crystal monolayer in the
presence of the liquid crystal bulk. It was found that capillary flow causes
the first monolayer of liquid crystal molecules in contact with the fatty acid
monolayer to be oriented in the flow direction with a large pretilt (78
degrees), resulting in a quasi-planar alignment with splay-bend deformation of
the nematic director in the bulk. itself is affected by the flow. The
quasi-planar flow-induced alignment was found to be metastable. Once the flow
ceases, circular domains of homeotropic orientation nucleate in the sample and
expand until the whole sample becomes homeotropic. This relaxation process from
flow-induced quasi-planar to surface-induced homeotropic alignment was also
monitored by SHG. It was found that in the homeotropic state the first nematic
layer presents a pretilt of 38 degrees almost isotropically distributed in the
plane of the cell, with a slight preference for the direction of the previous
flow.Comment: LaTeX2e article, 11 figures, 17 EPS files, submitte
Kontroversi PP 84/1999 : Konflik Elite dengan Masyarakat Adat Tentang Batas Wilayah antara Kabupaten Agam dan Kota Bukittinggi
Conflict is a fact of life, not be avoided, and often creative. Conflicts occur when the community goals is not running well, many disagreements and conflicts are solved without violence. Conflicts usually occur between the states (state officials) with the citizens, both individually and in groups. Hypothetically, conflicts occur because it is a result of government policy process that is not participatory and in next stage display dissent, discord, violence, and separatism. In this conflict, country has an interest in the conflict region, in the sense of conflict that is deliberately created for a macro benefit of the country. On the basis of this, the conflict between the Government of Bukittinggi and Agam controversy occurred as a result of the implementation of PP 84/1999
Low 25-OH vitamin D levels at time of diagnosis and recurrence of ovarian cancer.
The objective of this study was to evaluate the correlation between 25-OH vitamin D and ovarian cancer as a diagnostic marker or recurrence disease marker. We studied the following: (1) 61 women without gynecologic diseases, (2) 45 women affected by benign ovarian disease, (3) 46 women with recent diagnosis of ovarian cancer, (4) 26 follow-up women with recurrent ovarian cancer, and (5) 32 follow-up women with stable ovarian cancer. The 25-OH vitamin D was quantified with LUMIPULSE® G 25-OH vitamin D on LUMIPULSE® G 1200 (Fujirebio, Japan). As a threshold value, identified by ROC curve analysis, 20.2 ng/mL (sensitivity 73.3 %, specificity 84 %) was chosen corresponding to the limit between sufficient and insufficient 25-OH vitamin D according to the WHO. Low 25-OH vitamin D levels were observed in 26 % of women without gynecologic diseases, in 80 % of women with recent diagnosis of ovarian cancer and in 24 % women affected by benign ovarian diseases (p < 0.001). The follow-up study showed an insufficient level of 25-OH vitamin D in 73 % women with recurrent ovarian cancer and in 47 % women with stable ovarian cancer (p < 0.0003). This study showed that patients with ovarian cancer are often insufficient in 25-OH vitamin D compared to women with benign ovarian diseases. The women with recurrent ovarian cancer presented more often low levels compared to women with stable ovarian cancer. This study suggests that 25-OH vitamin D, due to its antiproliferative properties, can be a good marker for ovarian cancer also
Phase-matched second-harmonic generation in a ferroelectric liquid crystal waveguide
True phase-matched second-harmonic generation in a waveguide of crosslinkable
ferroelectric liquid crystals is demonstrated. These materials allow the
formation of macroscopically polar structures whose order can be frozen by
photopolymerization. Homeotropic alignment was chosen which offers decisive
advantages compared to other geometries. All parameters contributing to the
conversion efficiency are maximized by deliberately controlling the
supramolecular arrangement. The system has the potential to achieve practical
level of performances as a frequency doubler for low power laser diodes.Comment: 4 pages, LaTeX2e article, 3 figures, 4 EPS files, submitted to
Physical Review Letter
Oral contraceptives combined with interferon β in multiple sclerosis
Objective: To test the effect of oral contraceptives (OCs) in combination with interferon b (IFN-b)
on disease activity in patients with relapsing-remitting multiple sclerosis (RRMS).
Methods: One hundred fifty women with RRMS were randomized in a 1:1:1 ratio to receive IFNb-1a
subcutaneously (SC) only (group 1), IFN-b-1a SC plus ethinylstradiol 20 mg and desogestrel
150 mg (group 2), or IFN-b-1a SC plus ethinylestradiol 40 mg and desogestrel 125 mg (group 3).
The primary endpoint was the cumulative number of combined unique active (CUA) lesions on
brain MRI at week 96. Secondary endpoints included MRI and clinical and safety measures.
Results: The estimated number of cumulative CUA lesions at week 96 was 0.98 (95% confidence
interval [CI] 0.81–1.14) in group 1, 0.84 (95% CI 0.66–1.02) in group 2, and 0.72 (95% CI
0.53–0.91) in group 3, with a decrease of 14.1% (p 5 0.24) and 26.5% (p 5 0.04) when comparing
group 1 with groups 2 and 3, respectively. The number of patients with no gadoliniumenhancing
lesions was greater in group 3 than in group 1 (p 5 0.03). No significant differences
were detected in other secondary endpoints. IFN-b or OC discontinuations were equally distributed
across groups.
Conclusions: Our results translate the observations derived from experimental models to patients,
supporting the anti-inflammatory effects of OCs with high-dose estrogens, and suggest possible
directions for future research
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