39 research outputs found

    The pattern of reproduction in the Libyan jird (Meriones libycus; Rodentia: Muridae) from central Saudi Arabia in the absence of rainfall

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    The reproductive pattern of the Libyan jird (Meriones libycus Lichtenstein, 1823) from central Saudi Arabia was investigated in the absence of rainfall. In this study, body mass, morphometry of the reproductive tract, the histology of the reproductive organs, and the hormone concentrations of males and females were studied over 12 consecutive months in a wild population of the Libyan jird from central Saudi Arabia. Previous studies have found the breeding season of the Libyan jird from the Sahara desert of Algeria to occur during the wet months of spring. In the absence of rainfall, temperature and photoperiod were found to be important activators of reproductive activity. The cooler temperatures and shorter days of winter triggered the onset of ovulation in females and increased testes size and seminiferous tubule diameter in males. Only two pregnancies were found during the sampling period, which occurred during the cooler winter and early spring and coincided with a rise in plasma progesterone concentration in females. The Libyan jird was found to shift its breeding to the cooler months of winter in the absence of rainfall. This study strengthens the findings that changes in rainfall and temperature in dry deserts are critical cues for the onset of reproduction in small mammals.The Deanship of Scientific Research at the King Saud University through Vice Deanship of Research Chairs and King Abdulaziz City for Science and Technology (KACST) through Graduate Research Program. N.C.B. acknowledges funding from the SARChI chair of Mammalian Behavioural Ecology and Physiology from the DST–NRF South Africa, the National Research Foundation (grant No. 64756), and the University of Pretoria.http://www.nrcresearchpress.com/journal/cjzhj2019Zoology and Entomolog

    The β3-integrin endothelial adhesome regulates microtubule-dependent cell migration

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    Integrin β3 is seen as a key anti-angiogenic target for cancer treatment due to its expression on neovasculature, but the role it plays in the process is complex; whether it is pro- or anti-angiogenic depends on the context in which it is expressed. To understand precisely β3's role in regulating integrin adhesion complexes in endothelial cells, we characterised, by mass spectrometry, the β3-dependent adhesome. We show that depletion of β3-integrin in this cell type leads to changes in microtubule behaviour that control cell migration. β3-integrin regulates microtubule stability in endothelial cells through Rcc2/Anxa2-driven control of active Rac1 localisation. Our findings reveal that angiogenic processes, both in vitro and in vivo, are more sensitive to microtubule targeting agents when β3-integrin levels are reduced

    Visualization of calcium phosphate cement in teeth by zero echo time H-1 MRI at high field

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    Contains fulltext : 184112.pdf (publisher's version ) (Closed access

    Rational design of a stable peroxidase mimic for colorimetric detection of H2O2 and glucose: A synergistic CeO2/Zeolite Y nanocomposite

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    Owing to the high costs and instability of natural enzymes, the development of enzyme mimics based on inorganic nanomaterials has attracted a wide concern in recent years. In this work, a stable nanocomposite composed of highly dispersed CeO2 nanoparticles decorated on zeolite Y as support (CeO2/Y) was synthesized by a facile wet impregnation method, and the CeO2/Y nanocomposite was firstly proposed as an efficient peroxidase-mimicking nanozyme for accurate detection of H2O2 and glucose. The best catalyst was the nanocomposite with CeO2 to zeolite Y mass ratio of 0.20 (denoted as 20CeO2/Y), showing a better affinity and higher catalytic constant to the substrate of H2O2 and 3,3′,5,5′-tetramethylbenzidine (TMB) than horseradish peroxidase (HRP) enzymes by the steady-state kinetic analysis. The enzyme-mimicking catalyst could be used over a wider range of pH and temperature for a long-time reuse in TMB oxidation. A facile colorimetric assay was set up for the accurate detection of H2O2 and glucose, with the detection limits of 0.323 μM and 35.4 μM, respectively. The CeO2/Y-based peroxidase mimic was used to precisely detect the glucose concentration in real blood serum samples, exhibiting a great potential to be constructed as a reliable biosensor for glucose detection in some complex systems. The superior peroxidase-mimicking performance of CeO2/Y nanocomposite is attributed to the synergistic effects of outstanding activity of highly dispersed CeO2 nanoparticles (5–10 nm) and adsorption properties of zeolite Y with large surface area (517 m2·g−1) and pore volume (0.329 cm3·g−1).This work was sponsored by Shanghai Pujiang Program , China (No. 16PJ1401100 ), and the Shanghai Committee of Science and Technology , China (No. 15ZR1402000 ), Key Basic Research Program of Science and Technology Commission of Shanghai Municipality ( 17JC1400100 ), the NSF of China (51372041 , 51422202 , 21673048 , and 21875044 ), Youth Top-notch Talent Support Program of China.Scopu

    Assessment of prevalence and measurement of mandibular lingual concavities using Cone-Beam Computerized Tomography (CBCT) among patients in Jeddah: a cross-sectional study

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    OBJECTIVE: Dental implant procedure is the most common way to restore missing teeth but also comes with several complications. Success rates for dental implants are expected to be good when proper diagnosis and planning, study of bone morphology and closeness of implant with vital structures, such as nerves and blood vessels, are made pre-surgery. PATIENTS AND METHODS: This cross-sectional study involved 636 adult patients, aged 18-80 years old, that came for dental implants in screening clinics or referred to specialty clinics in Jeddah, Saudi Arabia for the year 2019 to 2020. Instead of conventional Computed Tomography (CT), Cone Beam Computed Tomography (CBCT) X-Rays have been used to evaluate mandibular lingual concavities. RESULTS: Prevalence and measurement of lingual concavities were determined. Type U mandibles with a lingual concavity, were found to have a higher chance of lingual cortical plate but this may still vary on factors such as type of population and ethnicity. The typical finding in the mandibular posterior region is the lingual undercut. CONCLUSIONS: CBCT is a great tool used to study mandibular lingual concavities and it is essential prior the installation of dental implant to prevent life-threatening complications

    Histomorphometric Evaluation of Peri-Implant Bone Response to Intravenous Administration of Zoledronate (Zometa(®)) in an Osteoporotic Rat Model

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    Contains fulltext : 229159.pdf (publisher's version ) (Open Access)We evaluated the response to peri-implant bone placed in the femoral condyle of osteoporotic rats, following intravenous zoledronate (ZOL) treatment in three settings: pre-implantation (ZOL-Pre), post-implantation (ZOL-Post), and pre- + post-implantation (ZOL-Pre+Post). Twenty-four female Wistar rats were ovariectomized (OVX). After 12 weeks, the rats received titanium implants in the right femoral condyle. ZOL (0.04 mg/kg, weekly) was administered to six rats 4 weeks pre-implantation and was stopped at implant placement. To another six rats, ZOL was given post-implantation and continued for 6 weeks. Additional six rats received ZOL treatment pre- and post-implantation. Control animals received weekly saline intravenous injections. At 6 weeks post-implantation, samples were retrieved for histological evaluation of the percentage of bone area (%BA) and of the percentage of bone-to-implant contact (%BIC). BA% for ZOL-Pre (29.6% ± 9.0%) and ZOL-Post (27.9% ± 5.6%) rats were significantly increased compared to that of the controls (17.3% ± 3.9%, p < 0.05). In contrast, ZOL-Pre+Post rats (20.4% ± 5.0%) showed similar BA% compared to Saline controls (p = 0.731). BIC% revealed a significant increase for ZOL-Post (65.8% ± 16.9%) and ZOL-Pre+Post (68.3% ± 10.0%) rats compared with that of Saline controls (43.3% ± 9.6%, p < 0.05), while ZOL-Pre rats (55.6% ± 19%) showed a BIC% comparable to that of Saline controls (p = 0.408). Our results suggest that receiving intravenous ZOL treatment before or after implant placement enhances peri-implant bone responses in terms of bone area. However, the effect of different ZOL treatment regimens on BIC% was found to be inconclusive

    Ordered porous metal oxide semiconductors for gas sensing

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    Among various gas sensing materials, metal oxide semiconductors have shown great potential as resistive type sensors. The ordered porous structural metal oxide semiconductors with well-defined meso- or macro-pores chemically synthesized via soft-templating method and nanocasting strategy have high porosity, highly interconnected pore channels and high surface area with enormous active sites for interacting with gaseous molecules. These features enable them good performance in gas sensing, including high sensitivity, fast response and recovery, good selectivity. This review gives a comprehensive summary about the porous metal oxides with focus on the synthesis methods, structure related properties, as well as the modification strategies for gas sensing improved performances. - 2018 The AuthorThis work was supported by the NSF of China (Nos. 51372041 , 51422202 , and 21673048 ), the �Shu Guang� Project (No. 13SG02) supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation , the National Youth Top-notch Talent Support Program in China, China Postdoctoral Science Foundation (No. KLH1615138 ), Shanghai Nature Science Foundation of China (Nos. 14ZR1416600 and 15ZR1402000 ), and Shanghai Pujiang Program , China (No. 16PJ1401100 ). The authors extend their appreciation to the International Scientific Partnership Program ISPP at King Saud University for funding this research work through ISPP# 0094

    Impact of Single or Combined Drug Therapy on Bone Regeneration in Healthy and Osteoporotic Rats

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    Complications in bone regeneration in patients with systemic impaired bone metabolism (e.g., osteoporosis) represent a rapidly increasing clinical challenge. Alendronate and simvastatin are drugs commonly used to promote bone metabolism in osteoporotic conditions. The aim of this study was to evaluate initial bone regeneration within osseous defects grafted with beta-tricalcium phosphate (β-TCP) in adjunction with systemic coadministrations of alendronate and simvastatin (i.e., daily subcutaneous injection for 3 weeks) in healthy and osteoporotic rats. Eighty Wistar female rats were ovariectomized (OVX; n = 40) or sham operated (n = 40). Six weeks later, osseous defects (a 3-mm critical-sized defect) were created in the left femoral condyles and then grafted with β-TCP. From the day following graft installation, OVX and sham animals received for 3 weeks a daily subcutaneous injection of alendronate (50 μg/kg of body weight) and simvastatin (5 mg/kg of body weight), alone or in combination. A control group was included, which received subcutaneous saline administration. At the end of the 3 weeks, rats were euthanized and specimens (femoral condyles) were retrieved for histological evaluation and histomorphometric measurements, that is, bone area (BA%) and remaining bone graft (RBG%). In osteoporotic rats, 3 weeks of daily subcutaneous injection of combined therapy (alendronate plus simvastatin) led to a significant (p < 0.05) increase in BA% and a significant decrease in RBG% compared to healthy controls in osseous defects grafted with β-TCP (BA%: 28.6 ± 12.0 vs. 18.2 ± 7.6, RBG% 61.3 ± 11.1 vs. 70.7 ± 7.3). No significant differences in BA% and RBG% were found in the OVX rats for single treatments. Furthermore, healthy controls showed similar BA% and RBG% upon single or combined therapy compared to nontreated control rats. Daily coinjections (for 3 weeks) of alendronate plus simvastatin result in a significant enhancement of bone regeneration within osseous defects grafted with β-TCP in osteoporotic rats. Despite the expected effects on osteoporotic bone, our study did not confirm the hypothesized benefit of alendronate and simvastatin on bone regeneration in osseous defects in healthy conditions. The efficacy of the combination drug therapy on bone regeneration demands further investigation to elucidate molecular and cellular aspects underlying this therapy
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