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1.
Theriogenology ; 175: 89-94, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34517287

RESUMO

Cortisol (C) and dehydroepiandrosterone (DHEA) are recognized as the main fetal steroids, and they are likely to influence fetal development and have long-term effects on newborn hypothalamic-pituitary-adrenal axis (HPA) function. DHEA is often measured as its sulfates and expressed as DHEA-S. Hair analysis represents a promising methodological approach for the non-invasive measurement of steroids, allowing for a retrospective analysis of the total exposure to steroids over time, and avoiding the influence of acute events or circadian fluctuations. Hair cortisol and DHEA concentrations have been investigated in cows, but no studies have been performed on calves. The object of this study was to evaluate hair cortisol (HC) and hair DHEA-S (HDHEA-S) concentrations in beef calves from birth to six months of age. Hair samples of 12 beef calves (seven males, five females) were firstly collected at birth (T1) and then every three weeks up to six months of age (T2-T10), collecting only the re-grown hair. HC and HDHEA-S were analyzed by radioimmunoassay (RIA). Calves sex, weight and APGAR score were registered immediately after birth. Statistical analysis revealed that both HC and HDHEA-S were influenced by sampling time (P < 0.001). HC concentrations were higher at T1 compared to all subsequent samplings (T2-T10, P < 0.01); HC concentrations were higher at T2 compared to T4-T10 (P < 0.01), while no further changes were detected from T3 onward. Higher HDHEA-S concentrations were registered at T1, T2 and T3 compared to all the other samplings (P < 0.01). No correlation was found between hair concentrations of both steroids and calf sex or birthweight. APGAR score was negatively correlated only with HC at birth (P < 0.05). These data demonstrate that C and DHEA-S are quantifiable in the hair of calves and are influenced by their age. The higher HC detected at birth (T1) probably reflects the high serum C concentrations present late in pregnancy and increased by the fetal HPA axis, by which parturition is initiated in cows. The highest HDHEA-S at birth (T1) in calves indicates that the largest amounts of DHEA and its sulfates are produced during fetal development. Moreover, the findings of higher HC at three weeks after birth and of higher HDHEA-S until six weeks after birth, suggest that C and DHEA secretion continues also beyond birth, and that these steroids could be involved in the events occurring during the challenging first weeks of age in the calf.


Assuntos
Hidrocortisona , Sistema Hipotálamo-Hipofisário , Animais , Bovinos , Desidroepiandrosterona , Sulfato de Desidroepiandrosterona , Feminino , Masculino , Parto , Sistema Hipófise-Suprarrenal , Gravidez , Estudos Retrospectivos
2.
Anim Reprod Sci ; 214: 106313, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32087908

RESUMO

This study was conducted to assess concentrations of 17ß-estradiol (E2) and testosterone (T) in toe claws of puppies collected at birth, at 30 and at 60 days of age, evaluating changes relating to age and effect of puppy sex, Apgar score, bodyweight at birth, "litter effect", litter size, and maternal age. Puppies (n = 89), 46 males and 43 females, with normal weight and without malformations, were assigned for the study. Within 12 h of birth tips of toe claws were clipped, and the re-growth tissue of the claws was collected at 30 and 60 days of age. Steroid quantifications occurred using a radioimmunoassay. The results indicated there were lesser concentrations (P < 0.001) of both hormones at 30 and 60 days of age than at birth and that concentrations were similar at 30-60 days of age. There were greater (P < 0.001) T concentrations in males than females, with there being an interaction between sex and sampling time (P < 0.01). The Apgar score was positively (P < 0.001) related to T concentrations in toe claws at birth. The bodyweight was positively correlated (P < 0.05) with T concentrations, with an interaction among puppy sex, bodyweight and sampling time (P < 0.05). Results of the present study confirmed the usefulness of toe claws as a matrix for study of hormonal changes in perinatology of dogs. Results of the study also indicate there are greater E2 and T concentrations at birth compared with 30 and 60 days of age that could be the result of these prenatal steroids affecting fetal development.


Assuntos
Animais Recém-Nascidos/metabolismo , Cães/fisiologia , Estradiol/química , Casco e Garras/química , Testosterona/química , Animais , Estradiol/metabolismo , Feminino , Masculino , Testosterona/metabolismo
3.
Theriogenology ; 108: 277-283, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29277067

RESUMO

A proper canine neonatal assistance, required to reduce the high perinatal loss rate, imply a full knowledge about the fetal-to-neonatal physiology. Because fetal fluids play an important role throughout mammals pregnancy, influencing fetal growth and development, fetal well being, and contributing to guarantee the most suitable environment for the fetus, the knowledge about fetal fluids biochemical composition is of major importance. At first, the biochemical composition of fetal fluids collected by normal developed, healthy and viable newborns, is necessary to depict the normal features, and represent the first step for the further detection of abnormalities associated to fetal/neonatal distress and useful for the early identification of newborns needing special attention, immediately after birth. The present study was aimed to define the biochemical composition of amniotic and allantoic fluids collected from fetus delivered by caesarean section at term of pregnancy. To reduce the possible confounding effect of maternal labor or troubles at parturition, fetal fluids were collected only from puppies born by elective caesaeran section, at term of normal pregnancies. Fetal fluids from 76 puppies, 70 normal and six pathologic newborns, born by elective caesarean section were collected and analyzed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, lactate dehydrogenase (LDH), creatine-kinase (CK), alkaline phosphatase (ALP), creatinine, urea, amylase, lipase, gamma-glutamyl transferase (γ-GT), triglycerides, cholesterol, total proteins, albumin, globulins, glucose, magnesium, potassium, chloride, sodium, calcium, phosphorus and osmolarity. No significant differences were found between biochemical composition of amniotic or allantoic fluid in normal and pathologic newborns, maybe due to the small number of the pathologic puppies. Although some correlations between the two fluids were found (albumin, phosphorus, glucose and triglycerides), the results showed significant differences between the amniotic and allantoic biochemical composition (for all the parameters, except of alanine aminotransferase, triglycerides, cholesterol, albumin, amylase and glucose), suggesting that diverse sources could concur to the final composition of each fluid. A wide variability within and among litters was found for both amniotic and allantoic biochemical composition, and for some parameters an influence of breed body size (amniotic amylase, cholesterol, and allantoic calcium and glucose), maternal parity (amniotic and allantoic CK, glucose, LDH, chloride) and newborn gender (allantoic phosphorus) was found. Further investigations are needed for addressing the origin of each fetal fluid biochemical composition in the dog and also to indeep possible differences in fetal fluids biochemical composition between normal and pathologic puppies, providing potential markers for the quick identification of newborns that need special surveillance and cares immediately after birth.


Assuntos
Líquido Amniótico/química , Doenças do Cão/diagnóstico , Doenças Fetais/veterinária , Animais , Cães , Feminino , Doenças Fetais/diagnóstico , Gravidez
4.
Theriogenology ; 100: 114-119, 2017 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-28708525

RESUMO

The prostate commonly develops benign prostatic hyperplasia (BPH) in dogs over 5 years, while in aged dogs other pathological findings might be revealed by ultrasonographic exam. The aim of the present study was to estimate the most suitable age for a preventive ultrasonographic examination of the prostate in the dog. The prostate of 1003 intact male dogs of 64 different breeds, of different ages (1-18 years) and bodyweights (2-55 kg) was evaluated with ultrasound, irrespective of the reason for clinical examination. The age of each dog was expressed as the ratio between the actual age and the maximum longevity expected for the breed. Dogs were divided in two groups based on breeds' life expectancy as short life (SL) and long life (LL). The size of the prostate (normal, enlarged or small) and the presence of abnormal sonographic findings were recorded for each dog. The results of the present study indicate that the most suitable age for a preventive ultrasonographic exam of the prostate in the dog is approximately at 40% of its expected longevity, both in short and long life breeds, because at this age there is a strong possibility to be able to detect abnormal prostatic findings. In 47.5% of the dogs at least one abnormal finding of the prostate was revealed by ultrasonographic exam, while dogs with long life expectancy showed a significantly higher prevalence of abnormalities, than dogs with short life expectancy. The most frequent findings were the increase of prostatic size (33.5%) and the presence of at least one cyst (33.6%), with no difference between SL and LL dogs. In conclusion, a preventive examination of the prostate starting at 40% of expected longevity in dogs of short and long life breeds is strongly recommended for early detection of abnormalities, for scheduling specific follow up and for suggesting effective therapeutic protocols.


Assuntos
Envelhecimento , Doenças do Cão/diagnóstico por imagem , Próstata/diagnóstico por imagem , Hiperplasia Prostática/veterinária , Ultrassonografia/veterinária , Animais , Cães , Longevidade , Masculino , Hiperplasia Prostática/diagnóstico por imagem
5.
Nanoscale ; 9(16): 5234-5243, 2017 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-28397932

RESUMO

Prussian Blue Analog (PBA) nanoparticles were formed on a heterogeneous nanostructured surface made of an ordered nanoperforated titanium oxide thin film deposited on a gold layer. The study of the nanocomposite film by grazing-incidence wide angle X-ray scattering, infrared spectroscopy, scanning electron microscopy and atomic force microscopy shows that the PBA particles are precisely positioned within all the perforations of the oxide film over very large surface areas. Further investigation on the formation of the PBA particles demonstrates a decisive role of a heterogeneous nucleation of the coordination polymer driven by well-adjusted surfaces energies and reactant concentrations in the spatial positioning of the PBA particles. Thanks to the well-controlled positioning of the particles within the ordered nanoperforations, the latter were successfully used as nano crucibles for the local transformation of PBA into the corresponding metal alloy by heat treatment. The thin film heterostructure thus obtained, made of ferromagnetic islands isolated by diamagnetic walls, opens interesting perspectives for the design of magnetic storage devices.

6.
Theriogenology ; 88: 264-269, 2017 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-28234232

RESUMO

Along the perinatal period, in mammals, cortisol (C) plays a pivotal role in the final intrauterine fetal maturation and in the early neonatal adaptation. Because of the scarce knowledge about canine perinatology, the present study was aimed to assess the C concentrations in amniotic and allantoic fluids collected, without invasiveness, from small-sized, purebred newborn puppies born by elective cesarean section, at term of pregnancy. Possible correlations between fetal fluid C concentrations and maternal parity, litter size, birth weight, Apgar score, were evaluated. In addition, the possible effect of fetal fluid C concentrations on newborn survival at 24 hours of age, and the effect of the litter or the newborn gender on fetal fluid C concentrations were also assessed. The results, obtained from 50 born alive, normal-weight puppies, without gross physical malformation, showed that C concentration was higher in allantoic than in amniotic fluid (P < 0.01), even if a strong positive correlation between the two fluids C concentration was found (P < 0.0001; R = 0.83). Neither amniotic nor allantoic C concentrations were correlated to maternal parity, litter size, birth weight, and Apgar score. Interestingly, higher amniotic (P < 0.05), but not allantoic, C concentrations were found in puppies not surviving at 24 hours after birth. Therefore, it could be suggested that this parameter may be useful for the recognition, at birth, of puppies needing special surveillance during the first day of age. A significant (P < 0.001) effect of the litter in both amniotic and allantoic C concentrations was found. In conclusion, the present results showed that in small-sized purebred puppies, born at term by elective cesarean section, the exact fetal, maternal, or placental source contributing to fetal fluid C concentrations remains to be clarified. From a clinical perspective, however, the evaluation of amniotic C concentration at birth seems useful for the detection of puppies that need special surveillance during the first 24 hours of age, and should be coupled to the early newborn evaluation by Apgar score. However, the small total number of newborns, and especially of the dead puppies enrolled in the present study, suggests that further, more-focused investigations on a large number of subjects are needed before the method could be considered for application in the clinical practices.


Assuntos
Alantoide/metabolismo , Líquido Amniótico/metabolismo , Feto/metabolismo , Hidrocortisona/metabolismo , Prenhez/metabolismo , Animais , Peso ao Nascer , Tamanho Corporal , Cães , Feminino , Tamanho da Ninhada de Vivíparos , Gravidez , Sobrevida
7.
Reprod Domest Anim ; 51(5): 688-92, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27440379

RESUMO

Few information is available on parameters that can be used to objectively assess the foetal health during canine pregnancy. To identify a reliable parameter for the evaluation of foetal well-being, the effect of pre-gestational maternal bodyweight and gestational age on foetal heart rate (FHR) and on feto-maternal heart rate ratio (FHR/MHR) was investigated. Seventeen client-owned pregnant bitches of different pre-gestational maternal bodyweight were examined by serial echo colour Doppler. Only data from 11 uncomplicated pregnancies were included in the statistical analysis. The relationship between FHR, and FHR/MHR, and independent variables was analysed by polynomial regression (p ≤ .05). The FHR and the FHR/MHR significantly fitted a multiple quadratic regression for all independent variables. They both increased from 35 to 20 days before parturition and then a decreasing pattern followed. Higher values of both parameters were observed in bitches of lowest and highest bodyweight. Patterns of FHR and FHR/MHR were similar, but the ratio better describes the effect of the independent variables on the data. Thus, the highest significance of FHR/MHR compared to FHR alone encourages the application of this ratio to evaluate foetal well-being. The equation derived by the regression analysis of FHR/MHR could be applied in clinical practice to obtain its expected values in healthy pregnancies.


Assuntos
Tamanho Corporal/fisiologia , Cães/fisiologia , Frequência Cardíaca/fisiologia , Prenhez , Animais , Feminino , Gravidez , Prenhez/fisiologia
8.
J Dairy Sci ; 98(10): 6897-904, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26254531

RESUMO

Epithelial cells are shed into milk during lactation, and although they generally reflect the cellular characteristics of terminally differentiated luminal cells, previously the detection of more primitive cells was described in human milk where a cell population of epithelial lineage was detected expressing markers typical of progenitor cells. In this investigation, we report the development of flow cytometry analysis to allow multiparametric assessment of mammary epithelial cells observed in milk. Cells collected from milk samples of 10 healthy dairy cows were directly analyzed for 6 different markers: CD45, CD49f, cytokeratin 14, cytokeratin 18, presence of nucleus, and cell viability. Milk samples were collected in 3 different periods of lactation: early lactation (EL=d 0-30), mid-lactation (ML=d 90-120), and late lactation (LL=210-250). Here we identify the differential expression of precursor or differentiated cell markers (or both) in mammary epithelial cells present in bovine milk. Myoepithelial cells, as indicated by cells staining positively for cytokeratin 14(+)/cytokeratin 18(-), were observed to increase from EL to LL with a high correlation with nuclear staining inferring potential proliferative activity. Furthermore, a significant increase in CD49f(+) and cytokeratin 14(+)/cytokeratin 18(+) positive cells was observed in LL. This assay is a sensitive approach for evaluating the variations in the frequency and features of living epithelial cells, whose reciprocal balance may be significant in understanding mammary gland cellular function throughout lactation. These observations suggest that mammary epithelial cell immunophenotypes could be investigated as biomarkers for mammary gland function in dairy cows.


Assuntos
Bovinos/fisiologia , Lactação , Glândulas Mamárias Animais/citologia , Leite/citologia , Leite/imunologia , Animais , Contagem de Células/veterinária , Diferenciação Celular , Sobrevivência Celular , Células Epiteliais/classificação , Células Epiteliais/imunologia , Células Epiteliais/fisiologia , Feminino , Imunofenotipagem/veterinária , Glândulas Mamárias Animais/metabolismo , Leite/metabolismo
9.
Theriogenology ; 84(5): 791-6, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26081135

RESUMO

The last stage of fetal development and the neonatal period represent the most critical phases for the mammals' offspring. In the dog, the knowledge about the final intrauterine fetal development and biology, as well as about the neonatal physiology, remains scarce. Hormonal changes occurring in the last intrauterine fetal phase and during the early neonatal age are still not completely clear, probably because of the invasiveness related to the collection of the more common biological matrix, represented by circulating blood. Toward term of pregnancy, during parturition, and after birth, the hypothalamic-pituitary-adrenal axis is a key system regulating several physiological processes, and its activity was previously investigated by blood analysis, considered an invasive procedure providing a single-point measurement. In respect to animal welfare, and for a more correct long-term retrospective investigation, noninvasive hormonal studies were performed firstly on the hair of humans and coat of animals and, more recently, in the nails of human beings. This study was aimed to assess cortisol (COR) in coat and claws of newborn puppies and to evaluate the possible influence of the newborn gender, breed body size, and age on coat and claws COR concentrations. The results obtained from 165 newborn puppies evidenced that coat and claws COR levels were highly correlated each other (P < 0.0001), although the COR accumulation in the two matrices was different in relation to the class of age. Moreover, the puppies age influenced both coat and claws COR concentrations (P < 0.05), with premature puppies showing higher values when compared to term born-dead puppies or puppies dead between 1 and 30 days of age. The present study reported that COR is quantifiable in coat and claws of newborn dogs. Moreover, both matrices appear as useful tools for new, noninvasive, long-term perinatal and neonatal researches also in canine species.


Assuntos
Animais Recém-Nascidos/metabolismo , Cabelo/metabolismo , Casco e Garras/metabolismo , Hidrocortisona/metabolismo , Animais , Animais Recém-Nascidos/fisiologia , Cães/metabolismo , Cães/fisiologia , Feminino , Masculino , Fatores Sexuais
10.
Nanoscale ; 7(12): 5371-82, 2015 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-25723817

RESUMO

Capillary phenomena governing the mass-transport (capillary filling, condensation/evaporation) has been experimentally investigated in around 20 different silica thin films exhibiting various porosities with pores dimension ranging from 2 to 200 nm. Films have been prepared by sol-gel chemistry combined with soft-templating approaches and controlled dip coating process. Environmental ellipsometric porosimetry combined with electronic microscopy were used to assess the porosity characteristics. Investigation of lateral capillary filling was performed by following the natural infiltration of water and ionic liquids at the edge of a sessile drop in open air or underneath a PDMS cover. The Washburn model was applied to the displacement of the liquid front within the films to deduce the kinetic constants. The role of the different capillary phenomena were discussed with respect to the porosity characteristics (porosity vol%, pore dimensions and constrictions). We show that correlation between capillary filling rate and pore dimensions is not straightforward. Generally, with a minimum of constrictions, faster filling is observed for larger pores. In the case of mesopores (<50 nm in diameter), the presence of bottle necks considerably slows down the infiltration rate. At such a small dimension, evaporation/capillary condensation dynamics, taking place at the meniscus inside the porosity, has to be considered to explain the transport mode. This fundamental study is of interest for applications involving liquids at the interface of mesoporous networks such as nanofluidics, purification, separation, water harvesting or heat transfer.

11.
J Ultrasound ; 17(4): 287-92, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25368686

RESUMO

PURPOSE: The ductus venosus (DV) blood flow has been studied in fetal lambs and in humans. This study aims to describe the velocities, the Doppler indices and the morphological patterns of the venous blood flow in the DV of canine fetuses during physiological pregnancy. METHODS: The DV of 55 canine fetuses has been evaluated and the waveforms described using B-mode, color and pulsed-wave Doppler ultrasound technology. RESULTS: We found 48 diphasic waves and 7 threephasic waves. No monophasic waveform was found. Six of seven threephasic waveforms belonged to litters in which perinatal mortality occurred. The peak velocity during ventricular systole S (cm/s), the peak velocity during the ventricular diastole D (cm/s), the velocity during atrial contraction aV (cm/s), the S/D index, the pulsatility index (PI) and the resistance index were measured. CONCLUSIONS: All Doppler indices and velocities were significantly correlated with each other (p < 0.05). The number of newborn puppies and the age of bitches were not related to DV vascular indices or flow rate (p > 0.05). Gestational age was proportional to the PI (p < 0.02). Doppler ultrasonography allows the assessment of DV blood flow in canine fetuses during pregnancy.

12.
Int J Immunopathol Pharmacol ; 26(1 Suppl): 43-9, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24046948

RESUMO

Skin substitutes are epidermal, dermal or complete bilayered constructs, composed by natural or synthetic scaffolds and by adherent cells such as fibroblasts, keratinocytes or mesenchymal stem cells. Silk fibroin is a promising polymer to realize scaffolds, since it is biocompatible, biodegradable, and exhibits excellent mechanical properties in terms of tensile strength. Moreover, fibroin can be added of others components in order to modify the biomaterial properties for the purpose. The aim of this work is to prepare silk fibroin films for adipose-derived stem cell (ADSCs) culture as a novel feeder layer for skin tissue engineering. Pectin has been added to promote the protein conformational transition and construct strength, while glycerol as plasticizer, providing biomaterial flexibility. Eighteen formulations were prepared by casting method using fibroin, pectin (range 1-10% w/w), and glycerol (range 0-20% w/w); films were characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry assay, to select the optimal composition. A stable fibroin conformation was obtained using 6% w/w pectin, and the best mechanical properties were obtained using 12% w/w glycerol. Films were sterilized, and human ADSCs were seeded and cultured for 15 days. Cells adhere to the support assuming a fibroblastic-like shape and reaching confluence. The ultrastructural analysis evidences typical active-cell features and adhesion structures that promote cell anchorage to the film, thus developing a multilayered cell structure. This construct could be advantageously employed in cutaneous wound healing or where the use of ADSCs scaffold is indicated either in human or veterinary field.


Assuntos
Tecido Adiposo/citologia , Fibroínas/química , Pele/citologia , Células-Tronco/citologia , Engenharia Tecidual/métodos , Varredura Diferencial de Calorimetria , Células Cultivadas , Humanos , Espectroscopia de Infravermelho com Transformada de Fourier , Esterilização
13.
Theriogenology ; 80(5): 526-32, 2013 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-23791425

RESUMO

A routine use of boar-sexed semen is limited by the long sorting time necessary to obtain an adequate number of sexed spermatozoa for artificial insemination and by the high susceptibility of spermatozoa of this species to damages induced by sorting procedure and subsequent cryopreservation. The aim of this work was to study the impact of encapsulation in barium alginate membrane on sorted boar spermatozoa by evaluating membrane integrity, chlortetracycline staining patterns, protein tyrosine phosphorylation, and Hsp70 immunolocalization during storage over 72 hours in liquid or encapsulated form. The encapsulation procedure significantly (P < 0.05) decreased the overall membrane integrity of control unsorted semen (81.8 vs. 57.4, CTR vs. CPS), but did not negatively affect the overall viability and the chlortetracycline staining patterns of sorted encapsulated cells. Moreover, encapsulation significantly decreased (P < 0.05) the overall phosphotyrosin A pattern cell percentage in unsorted (98.4 vs. 92.6, CTR vs. CPS) but not in sorted semen (64.0 vs. 74.2; SORT CTR vs. SORT CPS). As for Hsp70, the overall percentage of cells displaying the different patterns was significantly influenced (P < 0.05) by treatment but not by storage time. The sorting procedure seems to induce the major changes, whereas encapsulation tends to exert a protective effect on sorted semen by increasing the percentage of spermatozoa displaying the T pattern (2.8 vs. 24.3; SORT CTR vs. SORT CPS). In conclusion, our data confirm that the damaging impact of the encapsulation in barium alginate capsules seems to be limited when compared with that of the sorting procedure and, moreover, the association of the two procedures does not result in an algebraic sum of the negative effects. These results suggest the possibility of a future utilization of the encapsulation technology in order to store sorted spermatozoa and permit their controlled release in the female genital tract.


Assuntos
Alginatos/farmacologia , Espermatozoides/efeitos dos fármacos , Suínos/fisiologia , Animais , Citometria de Fluxo/veterinária , Ácido Glucurônico/farmacologia , Proteínas de Choque Térmico HSP70/análise , Ácidos Hexurônicos/farmacologia , Masculino , Fosforilação , Proteínas Tirosina Quinases/metabolismo , Pré-Seleção do Sexo/veterinária
14.
Nanotechnology ; 24(14): 145702, 2013 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-23507583

RESUMO

Magnetization reversal processes in Co/Pt multilayers prepared on nanoperforated templates are probed by magnetization relaxation measurements. The signature of pinning controlled domain wall movement as expected for percolated media is identified. This contrasts with the nucleation-type reversal mechanism of a Co/Pt reference film prepared on a smooth substrate. A zero field energy barrier of 93kBT is determined by fluctuation field measurements and is elucidated by micromagnetic calculations using the nudged elastic band method. This value is sufficiently large to qualify the material as a promising percolated medium.

15.
J Small Anim Pract ; 54(2): 87-91, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23373835

RESUMO

OBJECTIVES: To investigate the feasibility of percutaneous epididymal sperm aspiration in dogs and whether it might provide a population of epididymal spermatozoa similar to the population that can be obtained by processing isolated epididymis caudae. METHODS: Concentration and total sperm number, motility, morphology and acrosomal integrity of spermatozoa retrieved by percutaneous epididymal sperm aspiration, in vitro aspiration and mincing of the cauda of the epididymis were compared. RESULTS: Percutaneous epididymal sperm aspiration is a feasible procedure to retrieve a population of spermatozoa in dogs. Quality is similar to that of spermatozoa collected in vitro, although a wide variation amongst animals was observed. CLINICAL SIGNIFICANCE: In case of ejaculation failure due to pathological conditions in dogs, the collection of spermatozoa from the cauda of the epididymis could be an option for providing gametes for assisted reproductive technologies. Percutaneous epididymal sperm aspiration can be used in dogs with compromised reproductive performance, in which orchiectomy cannot be performed for medical or owner reasons. Further studies aimed to investigate whether the percutaneous epididymal sperm aspiration technique might be feasible for repeated semen collection and to accurately evaluate side effects are required.


Assuntos
Cães/fisiologia , Epididimo/citologia , Técnicas Reprodutivas/veterinária , Espermatozoides/fisiologia , Animais , Ejaculação/fisiologia , Epididimo/fisiologia , Masculino , Contagem de Espermatozoides/veterinária , Motilidade dos Espermatozoides/fisiologia , Sucção/veterinária
16.
Theriogenology ; 79(3): 495-501, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23218397

RESUMO

Insulin-like growth factor (IGF)-I represents one of the most important growth regulators, playing a central role in fetal and neonatal growth. Plasma IGF-I levels increase rapidly after birth, and they are influenced by numerous factors, including sex, age, nutritional state, and premature birth. The aims of this study were: (1) to evaluate the IGF-I plasma profile in healthy newborn foals during the first 2 weeks of life; (2) to assess the possible influence of sex and birth weight on this hormone; (3) to analyze the percentage increment of IGF-I values in healthy foals; (4) to evaluate the influence of prematurity on IGF-I profile; (5) to verify the role of IGF-I as a diagnostic marker of prematurity; and (6) to analyze the percentage increment of IGF-I in premature foals. Thirty-four healthy term foals were enrolled as the control group and from each foal plasma was collected within 6 hours from birth, at 12 hours, daily from Day 1 to Day 7, and at Days 10 and 14 after birth. Eleven foals aged younger than 1 week and diagnosed as premature and hospitalized at a Equine Perinatology Unit were also enrolled; from each foal plasma was collected daily from the day of admission to discharge or death. Insulin-like growth factor I was analyzed by RIA. In the control group, an increasing trend of IGF-I concentrations was found, with higher values from Day 4 to 10 compared with data obtained at less than 6 hours of life, and from Day 5 to 10 compared with 12 and 24 hours and 3 days. No differences were found in healthy foals analyzed in relation to birth weight and sex. In premature foals an increasing trend was observed but no statistical differences were found among sampling times, and no differences were found between healthy and premature foals. The IGF value in premature foals at admission was always higher compared with the lowest recorded level in healthy age-matched foals, thus this parameter does not seem to have a diagnostic role for prematurity in foals. Finally, the evaluation of the percentage increment of IGF-I concentrations showed a significant increase in full-term foals on Day 5, 6, 7, and 10 compared with 12 and 24 hours, and no differences were observed in premature foals. In conclusion, prematurity in newborn foals seems to affect only partially IGF-I plasma concentrations and it does not seem to be a reliable marker for this pathological condition.


Assuntos
Animais Recém-Nascidos/sangue , Idade Gestacional , Cavalos/sangue , Fator de Crescimento Insulin-Like I/análise , Nascimento Prematuro/veterinária , Animais , Biomarcadores/sangue , Peso ao Nascer , Feminino , Masculino , Nascimento Prematuro/sangue , Fatores Sexuais
17.
Reprod Domest Anim ; 47 Suppl 4: 353-8, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22827392

RESUMO

Encapsulation of boar semen is a novel technique that allows insemination to be performed as a single intervention without the need to dilute the semen. The research reviewed in this paper shows that spermatozoa encapsulated in alginate are able to achieve the same fertility as two or three inseminations per oestrus using standard techniques and unencapsulated cells. The use of encapsulated spermatozoa is currently limited by the need for longer semen processing time and wastage of disposable material (catheters, plastic bottles, etc.). In this review, the advantages, the drawbacks and the future possibilities for artificial insemination with encapsulated spermatozoa in the sow are discussed, with the aim of applying this promising new methodology for the optimization of sow reproductive performance.


Assuntos
Inseminação Artificial/veterinária , Sêmen/fisiologia , Manejo de Espécimes/veterinária , Suínos/fisiologia , Alginatos , Animais , Feminino , Inseminação Artificial/métodos , Masculino , Gravidez
18.
Reprod Domest Anim ; 47(1): 82-6, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21599765

RESUMO

The aim of this study was to compare the plasma profiles of 15-ketodihydro-PGF(2α) (PGM) in healthy neonates of three different species from birth until the third week of life. Twenty-four horse foals, 12 donkey foals, and 9 calves were studied. Blood samples were collected at 10, 20 and 30 min after birth, at 3, 24 and 72 h after birth, and at 7, 10, 17 and 21 days of life. All mothers experienced normal gestation lengths and normal, spontaneous deliveries. All newborns were judged mature and viable. Hormone concentrations were higher (p < 0.05) in horse foals 20 and 30 min after birth compared to later samples, and at 10 min in donkey foals compared to later samples (p < 0.05). In calves, higher (p < 0.05) concentrations of PGM were observed 10, 20, 30 min and 3 hours from parturition compared to later samples. These findings may be related to increased fetal placental unit production during parturition, while the relatively high PGF(2α) levels in the days after parturition may be connected with their role in completing organ maturation. Despite the existing differences between these species, the statistical analysis did not discover significant differences in PGM profiles during the first 3 weeks of life in donkey, horse and cattle newborns. The low levels observed 10 days after birth are possibly due to a fast completion of maturational development in these species.


Assuntos
Animais Recém-Nascidos/sangue , Bovinos/sangue , Dinoprosta/análogos & derivados , Equidae/sangue , Cavalos/sangue , Animais , Bovinos/crescimento & desenvolvimento , Dinoprosta/sangue , Equidae/crescimento & desenvolvimento , Cavalos/crescimento & desenvolvimento , Especificidade da Espécie
19.
Theriogenology ; 77(6): 1167-77, 2012 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-22153270

RESUMO

Thyroid hormones, insulin growth factor I (IGF-I) and non-esterified fatty acids (NEFA) represent important hormonal and metabolic factors associated with perinatal growth and maturation. Their action could be influenced by the type of parturition and the health status of the foal and therefore the aim of this work is to evaluate their plasma concentrations in newborn foals during the first 2 wks of life. Three groups of subjects were enrolled: 15 healthy foals born by spontaneous parturition, 24 healthy foals born by induced parturition and 26 pathologic foals. From each of the healthy foals, blood was collected at 10, 20 and 30 minutes, 3 and 12 hours from birth, daily from Day 1 to Day 7, and at Day 10 and 14 of life. In pathologic foals samples were collected twice a day from the day of admission at the hospital until the day of discharge or death. Thyroid hormones (T3 and T4) and IGF-I were analyzed by radioimmunoassay and NEFA by enzymatic-colorimetric methods. In all the three groups a declining trend of T3 and T4 plasma concentrations was detectable, with lower levels in the pathologic group compared to healthy foals. Spontaneous foals showed higher levels of T3 at 7 d compared to induced foals, while T4 levels were higher in spontaneous vs. induced foals before 6 h of life, at three and seven days. IGF-I showed increasing plasma concentrations in all three considered groups. No differences were found between healthy and pathologic foals. NEFA in spontaneous and induced healthy foals showed a declining trend with higher levels during the first hours of life. Pathologic foals presented higher levels compared to spontaneous foals only at 24 h and 10 d. These data suggest that the type of foaling could influence the reference ranges for thyroid hormones. Moreover, pathologic foals showed some hormonal and metabolic differences related to their health status. Above all changes of thyroid hormones levels, early in postnatal life, could be a cause, and not only a consequence, of the diseased condition of these foals.


Assuntos
Animais Recém-Nascidos/fisiologia , Cavalos/crescimento & desenvolvimento , Parto , Animais , Animais Recém-Nascidos/crescimento & desenvolvimento , Animais Recém-Nascidos/metabolismo , Ácidos Graxos não Esterificados/sangue , Nível de Saúde , Cavalos/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Hormônios Tireóideos/sangue
20.
Reprod Domest Anim ; 46 Suppl 2: 52-4, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21884278

RESUMO

The study takes into account the main steps and techniques for boar semen encapsulation, to optimize the instrumental insemination interventions. The use of cheap, biocompatible polymers as alginate can assure a regular, constant release of spermatozoa in the sow reproductive system, avoiding the double/triple intervention of insemination and reducing the employ of disposable materials. The encapsulation/microencapsulation of semen can therefore be the starting point of new, innovative systems of pig reproduction management.


Assuntos
Preservação do Sêmen/veterinária , Manejo de Espécimes/veterinária , Espermatozoides/fisiologia , Suínos/fisiologia , Animais , Feminino , Inseminação Artificial/veterinária , Masculino , Gravidez , Preservação do Sêmen/métodos , Manejo de Espécimes/métodos
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