43 Factors affecting vitrification of canine epididymal spermatozoa

2022 ◽  
Vol 34 (2) ◽  
pp. 256
Author(s):  
S. Stoddard ◽  
J. Linn ◽  
A. Lemma ◽  
G. Wirtu
Keyword(s):  
Factors Affecting ◽  
Epididymal Spermatozoa

135 THE EFFECT OF DIFFERENT TREATMENTS OF PORCINE EJACULATED AND EPIDIDYMAL SPERMATOZOA ON ROS GENERATION

2006 ◽  
Vol 18 (2) ◽  
pp. 176
Author(s):  
C. Matás ◽  
M. Sansegundo ◽  
S. Ruiz ◽  
J. Gadea
Keyword(s):  
Tyrosine Kinases ◽  
Protein Tyrosine Phosphatases ◽  
Ros Generation ◽  
Time Interval ◽  
Vitro Fertilization ◽  
Factors Affecting ◽  
Epididymal Spermatozoa ◽  
Humidified Air

The production of pig embryos in vitro is still relatively inefficient compared with results obtained with oocytes matured and fertilized in vivo. The main reasons for this limited performance are polyspermy after IVF and the poor developmental ability of embryos produced by IVM-IVF (Kikuchi et al. 2002 Biol. Reprod. 1033-1041). Between factors affecting polyspermy are the sperm procedures before IVF. Usually, these procedures including centrifugations that increase reactive oxygen species (ROS) formation in spermatozoa. ROS play an important role in sperm physiology including capacitation. Physiological concentrations of ROS have been proposed to enhance sperm capacitation by increasing cAMP synthesis and by inhibiting protein tyrosine phosphatases whilst activating tyrosine kinases. In general, epididymal spermatozoa appear to be able to capacitate and fertilize eggs in vitro much more easily than ejaculated spermatozoa (Yanagimachi Mammalian Fertilization. In: The Physiology of Reproduction, Raven Press 1988; 135-182). In this study, we investigated how different sources (ejaculated spermatozoa vs. epididymal spermatozoa) and sperm capacitating methods, usually employed in porcine IVF, could be affect ROS generation. Sperm-rich fractions from five fertile boars and sperm from five different epididyimides were used. The semen samples were then: (i) washed in Dulbecco's phosphate-buffered saline (DPBS) supplemented with 0.1% BSA, (ii) left unwashed, or (iii) washed on a Percoll (Pharmacia, Uppsala, Sweden) gradient (Mat�s et al. 2003 Reproduction 125, 133-141). Production of ROS was measured by incubating the spermatozoa in the in vitro fertilization medium (TALP) in the presence of 0.7 �m 22,72-dichlorodihydrofluorescein diacetate at 37�C under 5% CO2 in 100% humidified air. Every 15 min (from 15 to 135) the samples were analyzed and evaluated by flow cytometry. Measurements were expressed as the mean green intensity fluorescence units and it was used as index of ROS generation (Gadea et al. 2005 J. Androl. 26, 396-404). ANOVA analysis revealed a significant effect of sperm treatment on the ROS generation (P < 0.001). The highest value was obtained in sperm washed on a Percoll gradient and the lowest in unwashed semen. When ejaculated vs. epididymal semen was analyzed, the same tendency was observed in both. However, the values were always lower in epididymal semen than in ejaculated semen (P < 0.001). As a conclusion, ROS generation is different between treatments and between semen procedures for the time interval studied, and this finding may help to explain the different outcome in IVF among laboratories. This work was supported by Ministerio de Educaci�n y Ciencia, AGL2003-03144.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

Factors affecting dentist participation in a state Medicaid program

1990 ◽  
Vol 54 (11) ◽  
pp. 638-643 ◽  
Author(s):  
PC Damiano ◽  
ER Brown ◽  
JD Johnson ◽  
JP Scheetz
Keyword(s):  
Medicaid Program ◽  
Factors Affecting

Speech Therapy Services in a Large School System: A Six-Year Overview

1976 ◽  
Vol 7 (4) ◽  
pp. 207-219 ◽  
Author(s):  
Constance P. DesRoches
Keyword(s):  
School System ◽  
Speech Therapy ◽  
Factors Affecting ◽  
Case Load ◽  
Number Of Children ◽  
School Population ◽  
System A ◽  
Therapy Services ◽  
And Shifts ◽  
Selection Factors

A statistical review provides analysis of four years of speech therapy services of a suburban school system which can be used for comparison with other school system programs. Included are data on the percentages of the school population enrolled in therapy, the categories of disabilities and the number of children in each category, the sex and grade-level distribution of those in therapy, and shifts in case-load selection. Factors affecting changes in case-load profiles are identified and discussed.

Assessing the Link Between Perception and Production in Cantonese Tone Acquisition

2019 ◽  
Vol 62 (5) ◽  
pp. 1243-1257 ◽  
Author(s):  
Peggy Pik Ki Mok ◽  
Holly Sze Ho Fung ◽  
Vivian Guo Li
Keyword(s):  
Language Acquisition ◽  
General Principle ◽  
Choice Task ◽  
Factors Affecting ◽  
Tone Pair ◽  
Tone Production ◽  
Monosyllabic Words ◽  
Early Production ◽  
Forced Choice Task ◽  
Production Accuracy

Purpose Previous studies showed early production precedes late perception in Cantonese tone acquisition, contrary to the general principle that perception precedes production in child language. How tone production and perception are linked in 1st language acquisition remains largely unknown. Our study revisited the acquisition of tone in Cantonese-speaking children, exploring the possible link between production and perception in 1st language acquisition. Method One hundred eleven Cantonese-speaking children aged between 2;0 and 6;0 (years;months) and 10 adolescent reference speakers participated in tone production and perception experiments. Production materials with 30 monosyllabic words were transcribed in filtered and unfiltered conditions by 2 native judges. Perception accuracy was based on a 2-alternative forced-choice task with pictures covering all possible tone pair contrasts. Results Children's accuracy of production and perception of all the 6 Cantonese tones was still not adultlike by age 6;0. Both production and perception accuracies matured with age. A weak positive link was found between the 2 accuracies. Mother's native language contributed to children's production accuracy. Conclusions Our findings show that production and perception abilities are associated in tone acquisition. Further study is needed to explore factors affecting production accuracy in children. Supplemental Material https://doi.org/10.23641/asha.7960826

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