Evaluation of basal plasma α‐melanocyte‐stimulating hormone and adrenocorticotrophic hormone concentrations for the diagnosis of pituitary pars intermedia dysfunction from a population of aged horses     

T. W. MC GOWAN  G. P. PINCHBECK  C. M. MC GOWAN 《Equine veterinary journal》2013,45(1):66-73

Reasons for performing study: The sensitivity and specificity of basal plasma α‐melanocyte‐stimulating hormone (α‐MSH) and adrenocorticotrophic hormone (ACTH) for the diagnosis of pituitary pars intermedia dysfunction (PPID) has not been evaluated in a population‐based study. Objectives: To evaluate basal plasma α‐MSH and ACTH concentrations for the diagnosis of PPID in a population of horses aged ≥15 years. Methods: Owner‐reported data were obtained using a postal questionnaire distributed to an equestrian group. A subgroup of surveyed owners was visited and veterinary examination performed on horses aged ≥15 years. Blood samples were analysed for plasma α‐MSH and ACTH concentrations. Seasonally adjusted cut‐off values for α‐MSH and ACTH concentrations for the diagnosis of PPID were obtained using Youden index values against a clinical gold standard diagnosis (hirsutism plus 3 or more clinical signs of PPID). Results: α‐melanocyte‐stimulating hormone and ACTH were highly correlated with each other and with clinical and historical indicators of PPID. The increase in both α‐MSH and ACTH with increasing numbers of clinical signs in affected horses supports a spectrum of disease. Both variables were affected by season, with derived cut‐off values being higher in autumn compared with other seasons. Sensitivity and specificity were moderate and good in nonautumn seasons (59 and 93%, respectively) for α‐MSH using a cut‐off of 52.0 pmol/l. Sensitivity and specificity were good in nonautumn seasons (80 and 83%, respectively) for ACTH using a cut‐off of 29.7 pg/ml. For both α‐MSH and ACTH, sensitivity and specificity were close to 100% for samples obtained during the autumn period. Conclusions and potential relevance: Basal plasma α‐MSH and ACTH had moderate‐to‐good sensitivity and specificity for the diagnosis of PPID, which improved substantially during the autumn period, suggesting this may be the ideal time to test. Further studies to develop seasonally adjusted reference intervals for different geographical locations are warranted.  相似文献   

Identification of Sperm-Head Morphometric Subpopulations in Iberian Red Deer Epididymal Sperm Samples     

MC Esteso  MR Fernández-Santos  AJ Soler  V Montoro  F Martínez-Pastor  JJ Garde 《Reproduction in domestic animals》2009,44(2):206-211

Computer-assisted sperm morphometry analysis (CASMA) was used in this study to identify sperm morphometric subpopulations in Iberian red deer epididymal sperm samples. Epididymal sperm samples were collected from 37 mature stags and were divided. One portion was diluted in a Tris–citrate–egg yolk medium. A microscope slide was prepared from single extended sperm samples prior to freezing. The remainder of each sample was frozen in nitrogen vapours using a conventional protocol. After thawing, sperm smears were prepared as described for extended samples. All slides were air-dried and stained with Hemacolor^®. The sperm-head dimensions for a minimum of 145 sperm-heads were analyzed from each sample by means of the Sperm-Class Analyser^®, and the mean measurements recorded. Each sperm-head was measured for four primary sperm-head parameters, and five parameters of head shape. All sperm morphometric parameters evaluated were placed in a statistical database and a multivariate cluster analysis was performed. The clustering analyses, based on 10 867 individual spermatozoa, revealed the existence of three subpopulations (SP₁, SP₂, SP₃) of spermatozoa with different morphometric characteristics (p  <  0.001). The proportion of spermatozoa present in any of the three subpopulations remained constant (p  >  0.05) through the cryopreservation process. Pre-freeze and post-thaw sperm quality was in vitro evaluated by microscopic assessments of individual sperm motility and of plasma membrane and acrosome integrities. In conclusion, our results show that applying the CASMA techniques and multivariate cluster analyses, it was possible to determine that three subtle subpopulations of spermatozoa with different morphometric characteristics coexist in red deer semen.  相似文献