160 ZONA PELLUCIDA BIREFRINGENCE CORRELATES WITH CUMULUS MORPHOLOGY AND GLUCOSE-6-PHOSPHATE DEHYDROGENASE ACTIVITY OF EQUINE OOCYTES

2012 ◽  
Vol 24 (1) ◽  
pp. 192 ◽  
Author(s):  
A. Mohammadi-Sangcheshmeh ◽  
E. Held ◽  
D. Tesfaye ◽  
K. Schellander ◽  
M. Hoelker
Keyword(s):  
Light Microscopy ◽  
Zona Pellucida ◽  
Polarized Light ◽  
Polarized Light Microscopy ◽  
G6pd Activity ◽  
Developmental Competence ◽  
G6pdh Activity ◽  
Gentamicin Sulfate ◽  
Developmental Capacity ◽  
Glucose 6 Phosphate Dehydrogenase

The present study was conducted to determine the predictive value of zona pellucida birefringence (ZPB) measurement for developmental capacity of equine oocytes. In vitro developmental capacity of equine oocytes is related to cumulus morphology as well as glucose-6-phosphate dehydrogenase (G6PD) activity. Therefore, we classified equine oocytes according to cumulus morphology and G6PDH activity into groups of different developmental capacities and analysed the correlation between ZPB measured by polarized light microscopy and developmental competence. Ovaries were obtained from an abattoir and were transported to the laboratory within 2 to 4 h at 25 to 30°C in 0.9% saline. Cumulus–oocyte complexes (COC) were recovered by scraping the granulosa layer from opened follicles using a bone curette and were classified as having an expanded (Ex, n = 86) or compact (Cp, n = 93) cumulus. Other COC were subjected to 26 μM brilliant cresyl blue (BCB) in modified PBS for 90 min at 38.5°C and were categorised into BCB+ (blue cytoplasm, low G6PD activity, n = 89) and BCB– (colourless cytoplasm, high G6PD activity, n = 41) according to their ability to convert the BCB stain from blue to colourless. Following maturation for 28 to 30 h at 38.5°C in 5% CO2 in DMEM-F12 supplemented with 10% FCS, 5 mU mL–1 of FSH and 25 μg mL–1 of gentamicin sulfate, oocytes were imaged individually to assess zona thickness and ZPB by polarized light microscopy using OCTAX polarAIDE software (OCTAX, Bruckberg, Germany). Subsequently, oocytes were subjected to intracytoplasmic sperm injection using frozen-thawed stallion spermatozoa followed by culture in DMEM/F-12 medium (10% FCS and 25 μg mL–1 of gentamicin sulfate) under mineral oil (38.2°C, 5% CO2, 5% O2) for 8 days. Development rates were compared by chi-square test; variations in thickness and birefringence were analysed by Tukey's test and ANOVA. Higher maturation (58.4 vs 40.2%) and blastocyst rates (11.9 vs 3.8%) of Ex oocytes compared with Cp oocytes as well as higher proportions of BCB+ oocytes that matured (57.7% vs 28.1%), cleaved (45.9 vs 29.0%) and developed to the blastocyst stage (9.2 vs 1.4%) compared with BCB– oocytes (all P < 0.05) confirmed cumulus morphology and G6PDH activity as useful predictors for viability. Moreover, Ex oocytes had a thicker zona (18.2 ± 2.2 μm vs 17.3 ± 2.1 μm) and a higher birefringence (64.6 ± 5.2 vs 62.1 ± 4.2) compared with Cp oocytes (both P < 0.05). Concurrently, oocytes classified as BCB+ had a thicker zona (18.8 ± 2.4 μm vs 16.1 ± 2.0 μm) and higher values for birefringence (63.1 ± 4.5 vs 61.3 ± 3.3) compared with BCB– oocytes (both P < 0.05). Taken together, our results revealed that equine oocytes with higher developmental capacity have a thicker zona and greater birefringence scores compared with oocytes of lower developmental competence. Therefore, ZPB measurement provides a new, noninvasive method to assess the developmental competence of equine oocytes.

Morphological Characterization of a Sustained-Release Drug Implant by Scanning Electron Microscopy, Polarized Light Microscopy and Image Analysis

1998 ◽  
Vol 4 (S2) ◽  
pp. 932-933
Author(s):  
J.P. Neilly ◽  
J.S. Deng ◽  
J.L. House ◽  
J.A. Fagerland
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Sustained Release ◽  
Light Microscopy ◽  
Polymer Matrix ◽  
Polarized Light ◽  
Polarized Light Microscopy ◽  
Sustained Drug Release ◽  
Gentamicin Sulfate ◽  
Scanning Electron

Septacin is a sustained-release antibiotic currently under development by the Hospital Products Division of Abbott Laboratories. The product is designed to be used as an anti-infective implant in orthopedic surgical procedures with a sustained drug release for up to six weeks in vivo. It consists of gentamicin sulfate formulated with a bioerodable polyanhydride copolymer. The polymer is biodegradable and has been approved by the FDA for human clinical trials. The final product is obtained by mixing 20% gentamicin sulfate with molten polymer and injection molding it to form cylindrical Septacin beads.The microstructure of drug particles and polymer matrix is critical to the performance of sustained release products, thus scanning electron microscopy (SEM) and polarized light microscopy (PLM) were utilized in this study. SEM has proven useful for evaluating the microstructure of drug formulations3 and was used to examine the drug-polymer matrix structure. Average drug particle size and distribution were determined, and the drug-polymer boundary was evaluated.

351 POLARIZED LIGHT MICROSCOPY: DETECTION OF MICROTUBULES AND ITS EFFECTS ON THE VIABILITY OF IN VITRO-MATURED PORCINE OOCYTES

2010 ◽  
Vol 22 (1) ◽  
pp. 332 ◽  
Author(s):  
I. Molina ◽  
M. Muñoz ◽  
C. Díez ◽  
E. Gómez ◽  
E. A. Martínez ◽  
...  
Keyword(s):  
Light Microscopy ◽  
Polarized Light ◽  
Polarized Light Microscopy ◽  
Developmental Competence ◽  
Meiotic Spindle ◽  
Cleavage Rate ◽  
Cell Numbers ◽  
Oocyte Developmental Competence ◽  
Blastocyst Rate

The meiotic spindle in the oocyte is composed of microtubules and plays an important role during chromosome alignment and separation at meiosis. Polarized light microscopy (PLM) is used as a tool in human and, recently, in farm animals assisted reproductive technologies. PLM could be useful for a non-invasive evaluation of the meiotic spindle. The objectives of the present study were to assess the efficiency of PLM to detect microtubule-polymerized protein within in vitro-matured porcine oocytes and to examine the effects of PLM on the oocyte developmental competence. Cumulus-oocyte complexes from slaughterhouse ovaries were matured in vitro for 42 h as described by Gil et al. (2004 Theriogenology 62, 544-552). In the first experiment, a total of 97 oocytes from 6 replicates were placed individually in 10-μL drops of TCM-199-Hepes-FCS in a glass Petri dish. PLM was used to detect the presence of polymerized protein which could be forming a meiotic spindle. The presence of polymerized protein and a meiotic spindle was confirmed in individual oocytes by inmunostaining and chromatin detection as described by Morató et al. (2008 Mol. Reprod. Dev. 75, 191-201). In the second experiment, a total of 160 oocytes from 4 replicates were exposed or not (controls) to PLM for 10 minutes. Thereafter, the oocytes were parthenogenetically activated and cultured in vitro. Cleavage rate, total blastocyst rate, expanded blastocyst rate on Day 7 and total cell numbers in expanded blastocysts were assessed. Data were analyzed by GLM procedure of SAS. There was a positive correlation (r = 1; P < 0.0001) between the signal obtained by PLM and the presence of microtubule-polymerized protein as confirmed by inmunostaining. A positive PLM signal was detected in 98.9% of the oocytes. A barrel-shape spindle was observed in 94.8% of the individual samples by inmunostaining and all of these oocytes were positive to PLM. Moreover, oocytes exposed to PLM did not differ significantly from controls on cleavage rate (83.7 ± 1.5 v. 84.4 ± 1.5), total blastocyst rate (36.9 ± 3.6 v. 41.2 ± 3.6) and expanded blastocyst rate on Day 7 (21.9 ± 1.7 v. 26.2 ± 1.7), respectively. There were also no differences in total cell numbers counted in expanded blastocysts (32.8 ± 2.6 v. 35.6 ± 2.5). These results indicate that polarized light microscopy did not exert detrimental effects on porcine oocyte developmental competence and it seems an efficient system to detect polymerized protein in in vitro-matured porcine oocytes. Grant support: INIA: RZ2007-00013-00-00. I. Molina, M. Muñoz, B. Trigal and D. Martín are sponsored by INIA, RYC08-03454, Cajastur and PTA2007-0268-I, respectively.

scholarly journals Evaluation of equine oocyte developmental competence using polarized light microscopy

Reproduction ◽  
2017 ◽  
Vol 153 (6) ◽  
pp. 775-784 ◽  
Author(s):  
A Bertero ◽  
F Ritrovato ◽  
F Evangelista ◽  
V Stabile ◽  
R Fortina ◽  
...  
Keyword(s):  
Light Microscopy ◽  
Zona Pellucida ◽  
Light Microscope ◽  
Polarized Light ◽  
Developmental Competence ◽  
Immature Oocytes ◽  
Oocyte Developmental Competence ◽  
Morphological Evaluation ◽  
Meiotic Competence

The purpose of this study was to observe in vitro-matured equine oocytes with an objective computerized technique that involves the use of a polarized light microscope (PLM) in addition to the subjective morphological evaluation obtained using a classic light microscope (LM). Equine cumulus-oocyte complexes (COCs, n = 922) were subjected to different in vitro maturation times (24, 36 or 45 h), however, only 36-h matured oocytes were analyzed using CLM. The 36-h matured oocytes that reached maturity were parthenogenetically activated to evaluate the quality and meiotic competence. Average maturation percentages per session in groups 1, 2 and 3 (24-, 36- and 45-h matured oocytes respectively) were 29.31 ± 13.85, 47.01 ± 9.90 and 36.62 ± 5.28%, whereas the average percentages of immature oocytes per session were 28.78 ± 20.17, 7.83 ± 5.51 and 22.36 ± 8.39% respectively. The zona pellucida (ZP) birefringent properties were estimated and correlated with activation outcome. ZP thickness and retardance of the inner layer of the zona pellucida (IL-ZP) were significantly increased in immature oocytes compared with mature oocytes (P < 0.001 and P < 0.01 respectively). The comparison between parthenogenetically activated and non-activated oocytes showed a significant increase in the area and thickness of the IL-ZP in parthenogenetically activated oocytes (P < 0.01). These results show that the 36-h in vitro maturation (IVM) protocol allowed equine oocytes to reach maturity, and PLM observation of ZP can be used to distinguish mature and immature oocytes as well as activated and non-activated oocytes.

Ferroelastic domains and phase transitions in organic–inorganic hybrid perovskite CH3NH3PbBr3

2021 ◽  
Author(s):  
Maryam Bari ◽  
Alexei A. Bokov ◽  
Zuo-Guang Ye
Keyword(s):  
Phase Transitions ◽  
Electric Field ◽  
Light Microscopy ◽  
Domain Structure ◽  
Polarized Light ◽  
External Stress ◽  
Polarized Light Microscopy ◽  
Inorganic Hybrid ◽  
Hybrid Perovskite ◽  
Ferroelastic Domains

Polarized light microscopy reveals twin domains and symmetry of the phases in CH3NH3PbBr3 crystal; domain structure remains unresponsive to electric field but changes under external stress, confirming ferroelasticity while ruling out ferroelectricity.

scholarly journals Exploiting the Binocular Head in Polarized Light Microscopy

1994 ◽  
Vol 2 (4) ◽  
pp. 16-16
Author(s):  
Walter C. McCrone
Keyword(s):  
Light Microscopy ◽  
Polarized Light ◽  
Polarized Light Microscopy ◽  
The Other ◽  
Monocular Viewing ◽  
Area Of Interest

Having been brought up on monocular microscopes I find the omnipresent binocular systems a luxury. To support this viewpoint I'd like to suggest some benefits you may not have considered.Because I'm used to monocular viewing I sometimes use two different oculars, say 10X and 25X, in order to scan quickly to find an area of interest and then to examine the detail with higher magnification. Occasionally I use both oculars simultaneously and “concentrate” on either image to the exclusion of the other. A better way is to set the interocular distance at the extreme setting most different from your own interocular distance. By moving your head about a centimeter either way you can use either ocular.

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