394 research outputs found
Cumulus extracellular matrix is an important part of oocyte microenvironment in ovarian follicles: its remodeling and proteolytic degradation
The extracellular matrix (ECM) is an essential structure with biological activities. It has
been shown that the ECM influences gene expression via cytoskeletal components and the gene
expression is dependent upon cell interactions with molecules and hormones. The development
of ovarian follicles is a hormone dependent process. The surge in the luteinizing hormone triggers
ovulatory changes in oocyte microenvironment. In this review, we discuss how proteolytic cleavage
affects formation of cumulus ECM following hormonal stimulation; in particular, how the specific
proteasome inhibitor MG132 affects gonadotropin-induced cytoskeletal structure, the organization of
cumulus ECM, steroidogenesis, and nuclear maturation. We found that after the inhibition of proteolytic
cleavage, gonadotropin-stimulated oocyte–cumulus complexes (OCCs) were without any signs
of cumulus expansion; they remained compact with preserved cytoskeletal F-actin-rich transzonal
projections through the oocyte investments. Concomitantly, a significant decrease was detected in
progesterone secretion and in the expression of gonadotropin-stimulated cumulus expansion–related
transcripts, such as HAS2 and TNFAIP6. In agreement, the covalent binding between hyaluronan and
the heavy chains of serum-derived the inter-alpha-trypsin inhibitor, essential for the organization of
cumulus ECM, was missing
Physico-Chemical Properties Mediating Reproductive and Developmental Toxicity of Engineered Nanomaterials
With the increasing production of engineered nanomaterials (ENMs) exploited in many consumer products, a wider number of people is expected to be exposed to such materials in the near future, both in occupational and environmentalsettings. This has raised concerns about the possible implications on public health. In particular, very recently the scientific community has focused on the effect that ENMs might exert on the reproductive apparatus and on embryonic development. Indications that ENMs might have adverse effects on cells of the germ line and on the developing embryos have been reported. In the present minireview we will perform a critical analysis of the published work on reproductive and developmental toxicity of the most commonly used nanoparticles with a major focus on mammalian models. We will place emphasis on the main
physico-chemical characteristics that can affect NP behaviour in biological systems, i.e. presence of contaminants and nanoparticle destabilization, size,
dosage, presence of functional groups, influence of the solvent used for their suspension in biological media, aggregation/agglomeration, intrinsic chemical
composition and protein corona/opsonisation. The importance of this specific field of nanotoxicology is documented by the rapidly increasing number of
published papers registered in the last three years, which might be a consequence of the growing concerns on the possible interference of ENMs with reproductive ability and pregnancy outcome, in a time in which reproductive age has increased
and the possibility to bear children appears reduced
Synthesis and Structure-Activity Relationships of Pyridoxal-6-arylazo-5'-phosphate and Phosphonate Derivatives as P2 Receptor Antagonists.
Novel analogs of the P2 receptor antagonist pyridoxal-5'-phosphate-6-phenylazo-2',4'-disulfonate (PPADS) were synthesized. Modifications were made through functional group substitution on the sulfophenyl ring and at the phosphate moiety through the inclusion of phosphonates, demonstrating that a phosphate linkage is not required for P2 receptor antagonism. Substituted 6-phenylazo and 6-naphthylazo derivatives were also evaluated. Among the 6-phenylazo derivatives, 5'-methyl, ethyl, propyl, vinyl, and allyl phosphonates were included. The compounds were tested as antagonists at turkey erythrocyte and guinea-pig taenia coli P2Y(1) receptors, in guinea-pig vas deferens and bladder P2X(1) receptors, and in ion flux experiments by using recombinant rat P2X(2) receptors expressed in Xenopus oocytes. Competitive binding assay at human P2X(1) receptors in differentiated HL-60 cell membranes was carried out by using [(35)S]ATP-?-S. A 2'-chloro-5'-sulfo analog of PPADS (C(14)H(12)O(9)N(3)ClPSNa), a vinyl phosphonate derivative (C(15)H(12)O(11)N(3)PS(2)Na(3)), and a naphthylazo derivative (C(18)H(14)O(12)N(3)PS(2)Na(2)), were particularly potent in binding to human P2X(1) receptors. The potencies of phosphate derivatives at P2Y(1) receptors were generally similar to PPADS itself, except for the p-carboxyphenylazo phosphate derivative C(15)H(13)O(8)N(3)PNa and its m-chloro analog C(15)H(12)O(8)N(3)ClPNa, which were selective for P2X vs. P2Y(1) receptors. C(15)H(12)O(8)N(3)ClPNa was very potent at rat P2X(2) receptors with an IC(50) value of 0.82 ?M. Among the phosphonate derivatives, [4-formyl-3-hydroxy-2-methyl-6-(2-chloro-5-sulfonylphenylazo)-pyrid-5-yl]methylphosphonic acid (C(14)H(12)-O(8)N(3)ClPSNa) showed high potency at P2Y(1) receptors with an IC(50) of 7.23 ?M. The corresponding 2,5-disulfonylphenyl derivative was nearly inactive at turkey erythrocyte P2Y(1) receptors, whereas at recombinant P2X(2) receptors had an IC(50) value of 1.1 ?M. An ethyl phosphonate derivative (C(15)H(15)O(11)N(3)PS(2)Na(3)), whereas inactive at turkey erythrocyte P2Y(1) receptors, was particularly potent at recombinant P2X(2) receptors
Human adipose-derived stromal cells transplantation prolongs reproductive lifespan on mouse models of mild and severe premature ovarian insufficiency
Background
Although recent studies have investigated the ability of Mesenchymal Stromal Cells (MSCs) to alleviate short-term ovarian damage in animal models of chemotherapy-induced Premature Ovarian Insufficiency (POI), no data are available on reproductive lifespan recovery, especially in a severe POI condition. For this reason, we investigated the potential of MSCs isolated from human adipose tissue (hASCs), since they are easy to harvest and abundant, in ameliorating the length and performance of reproductive life in both mild and severe chemotherapy-induced murine POI models.
Methods
Mild and severe POI models were established by intraperitoneally administering a light (12 mg/kg busulfan + 120 mg/kg cyclophosphamide) or heavy (30 mg/kg busulfan + 120 mg/kg cyclophosphamide) dose of chemotherapy, respectively, in CD1 mice. In both cases, a week later, 1 × 106 hASCs were transplanted systemically through the tail vein. After four additional weeks, some females were sacrificed to collect ovaries for morphological evaluation. H&E staining was performed to assess stroma alteration and to count follicle numbers; immunofluorescence staining for αSMA was used to analyse vascularization. Of the remaining females, some were mated after superovulation to collect 2-cell embryos in order to evaluate their pre-implantation developmental capacity in vitro, while others were naturally mated to monitor litters and reproductive lifespan length. F1 litters’ weight, ovaries and reproductive lifespan were also analysed.
Results
hASC transplantation alleviated ovarian weight loss and size decrease and reduced alterations on ovarian stroma and vasculature, concurrently preventing the progressive follicle stockpile depletion caused by chemotherapy. These effects were associated with the preservation of the oocyte competence to develop into blastocyst in vitro and, more interestingly, with a significant decrease of chemotherapy-induced POI features, like shortness of reproductive lifespan, reduced number of litters and longer time to plug (the latter only presented in the severe POI model).
Conclusion
Human ASC transplantation was able to significantly reduce all the alterations induced by the chemotherapeutic treatment, while improving oocyte quality and prolonging reproductive functions, thus counteracting infertility. These results, strengthened by the use of an outbred model, support the potential applications of hASCs in women with POI, nowadays mainly induced by anticancer therapies
Human P2Y 1 Receptor: Molecular Modeling and Site-Directed Mutagenesis as Tools To Identify Agonist and Antagonist Recognition Sites
The molecular basis for recognition by human P2Y1 receptors of the novel, competitive antagonist 2′-deoxy-N6-methyladenosine 3′,5′-bisphosphate (MRS 2179) was probed using site-directed mutagenesis and molecular modeling. The potency of this antagonist was measured in mutant receptors in which key residues in the transmembrane helical domains (TMs) 3, 5, 6, and 7 were replaced by Ala or other amino acids. The capacity of MRS 2179 to block stimulation of phospholipase C promoted by 2-methylthioadenosine 5′-diphosphate (2-MeSADP) was lost in P2Y1 receptors having F226A, K280A, or Q307A mutations, indicating that these residues are critical for the binding of the antagonist molecule. Mutation of the residues His132, Thr222, and Tyr136 had an intermediate effect on the capacity of MRS 2179 to block the P2Y1 receptor. These positions therefore appear to have a modulatory role in recognition of this antagonist. F131A, H277A, T221A, R310K, or S317A mutant receptors exhibited an apparent affinity for MRS 2179 that was similar to that observed with the wild-type receptor. Thus, Phe131, Thr221, His277, and Ser317 are not essential for antagonist recognition. A computer-generated model of the human P2Y1 receptor was built and analyzed to help interpret these results. The model was derived through primary sequence comparison, secondary structure prediction, and three-dimensional homology building, using rhodopsin as a template, and was consistent with data obtained from mutagenesis studies. We have introduced a “cross-docking” procedure to obtain energetically refined 3D structures of the ligand–receptor complexes. Cross-docking simulates the reorganization of the native receptor structure induced by a ligand. A putative nucleotide binding site was localized and used to predict which residues are likely to be in proximity to agonists and antagonists. According to our model TM6 and TM7 are close to the adenine ring, TM3 and TM6 are close to the ribose moiety, and TM3, TM6, and TM7 are near the triphosphate chain
Adaptação do inventário parental “Language Use Inventory (LUI)” para crianças entre 18 e 47 meses para o português europeu : estudo piloto
Language acquisition and development takes in account the child’s interaction with the surrounding environment. Daily social interactions with people and communication with others allow the child to acquire language being pragmatics considered a system of rules that support the communicative use of language. Identification and assessment of children at risk for language disorders are crucial in order to carry out an effective early intervention. This study was carried out taking into account first, the relevance of pragmatics as a component of language, and second the lack of assessment tools in Portugal to assess these abilities. Therefore, the aim of this study consists on the translation, adaptation and validation of the inventory “Language Use Inventory” (LUI), to European Portuguese. The LUI is a standardized parent report measure designed to assess pragmatic language development in children within 18- to 47-month-old.Objetivo: A aquisição e o desenvolvimento da linguagem resultam
da interação da criança com o meio ambiente. As interações sociais
cotidianas com as pessoas e a comunicação com outros permitem que a
criança adquira linguagem, sendo a pragmática o sistema de regras que
suporta o uso comunicativo da linguagem. A identificação e a avaliação
de crianças em risco de desenvolverem transtornos de linguagem são
cruciais, tendo em vista a intervenção precoce eficaz. Tendo em vista a
relevância da pragmática como componente da linguagem e a escassez,
em Portugal, de instrumentos de avaliação da linguagem validados
para idades precoces, a finalidade deste estudo consistiu na tradução,
adaptação e validação do instrumento Language Use Inventory (LUI),
para o português europeu. O LUI é um inventário parental que avalia o
desenvolvimento da pragmática entre os 18 e os 47 meses. Métodos:
Foram adotados todos os procedimentos recomendados pelas diretrizes
internacionais sobre a adaptação de testes, culminando em estudo piloto
com uma amostra de 120 inventários, respondidos pelos pais/cuidadores
de crianças portuguesas da referida faixa etária. Resultados: Os
coeficientes de consistência interna (Alfa de Cronbach) para a versão
portuguesa do LUI situaram-se em 0,97 para a escala total e entre 0,71
e 0,96 para as subescalas. Conclusão: Os resultados preliminares dos
estudos de adaptação e de validação do LUI-Pt para crianças portuguesas
são promissores e asseguram a validade interna desta escala em termos
da sua dimensionalidade e consistência interna
Two-Minute k-Space and Time–accelerated Aortic Four-dimensional Flow MRI: Dual-Center Study of Feasibility and Impact on Velocity and Wall Shear Stress Quantification
PURPOSE: To investigate the two-center feasibility of highly k-space and time (k-t)–accelerated 2-minute aortic four-dimensional (4D) flow MRI and to evaluate its performance for the quantification of velocities and wall shear stress (WSS).
MATERIALS AND METHODS: This cross-sectional study prospectively included 68 participants (center 1, 11 healthy volunteers [mean age ± standard deviation, 61 years ± 15] and 16 patients with aortic disease [mean age, 60 years ± 10]; center 2, 14 healthy volunteers [mean age, 38 years ± 13] and 27 patients with aortic or cardiac disease [mean age, 78 years ± 18]). Each participant underwent highly accelerated 4D flow MRI (k-t acceleration, acceleration factor of 5) of the thoracic aorta. For comparison, conventional 4D flow MRI (acceleration factor of 2) was acquired in the participants at center 1 (n = 27). Regional aortic peak systolic velocities and three-dimensional WSS were quantified.
RESULTS: k-t–accelerated scan times (center 1, 2:03 minutes ± 0:29; center 2, 2:06 minutes ± 0:20) were significantly reduced compared with conventional 4D flow MRI (center 1, 12:38 minutes ± 2:25; P < .0001). Overall good agreement was found between the two techniques (absolute differences ≤15%), but proximal aortic WSS was significantly underestimated in patients by using k-t–accelerated 4D flow when compared with conventional 4D flow (P ≤ .03). k-t–accelerated 4D flow MRI was reproducible (intra- and interobserver intraclass correlation coefficient ≥0.98) and identified significantly increased peak velocities and WSS in patients with stenotic (P ≤ .003) or bicuspid (P ≤ .04) aortic valves compared with healthy volunteers. In addition, k-t–accelerated 4D flow MRI–derived velocities and WSS were inversely related to age (r ≥−0.53; P ≤ .03) over all healthy volunteers.
CONCLUSION: k-t–accelerated aortic 4D flow MRI providing 2-minute scan times was feasible and reproducible at two centers. Although consistent healthy aging- and disease-related changes in aortic hemodynamics were observed, care should be taken when considering WSS, which can be underestimated in patients
The relationship between S. aureus and branched-chain amino acids content in composite cow milk
The early diagnosis of mastitis is an essential factor for the prompt detection of the
animal for further actions. In fact, if not culled, infected cows must be segregated from the milking
herd and milked last, or milked with separate milking units. Besides microbiological analysis, the
somatic cell count (SCC) commonly used as predictor of intramammary infection, frequently lead
to a misclassification of milk samples. To overcome these limitations, more specific biomarkers
are continuously evaluated. The total amino acid content increases significantly in mastitic milk
compared to normal milk. S. aureus requires branched-chain amino acids (BCAAs—isoleucine,
leucine, and valine) for protein synthesis, branched-chain fatty acids synthesis, and environmental
adaptation by responding to their availability via transcriptional regulators. The increase of BCAAs
in composite milk has been postulated to be linked to mammary infection by S. aureus. The aim
of this work is to demonstrate, by a direct ion-pairing reversed-phase method, based on the use of
the evaporative light-scattering detector (IP-RP-HPLC-ELSD), applied to 65 composite cow milk
samples, a correlation between the concentration of isoleucine and leucine, and S. aureus load. The
correlation coe cient, r, was found to be 0.102 for SCC (p = 0.096), 0.622 for isoleucine (p < 0.0001),
0.586 for leucine (p < 0.0001), 0.013 for valine (p = 0.381), and 0.07 for tyrosine (p = 0.034), standing for
a positive correlation between S. aureus and isoleucine and leucine concentration. The link between
the content of BCAAs, isoleucine and leucine, and udder infection by S. aureus demonstrated with
our study has an important clinical value for the rapid diagnosis of S. aureus mastitis in cows.http://www.mdpi.com/journal/animalsam2020Paraclinical Science
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