Biomedical subjects

J R Correa

Publications and source records attributed to J R Correa.

25 records · Page 2Linked to original sources

PubMed1996

Assessment of new formulations of nonoxynol-9 coprecipitated with polyvinylpyrrolidone and iodine as possible vaginal contraceptives.

OBJECTIVE: To assess the in vitro spermicidal activity of new formulations of nonoxynol-9, coprecipitated with polyvinylpyrrolidone (PVP) or iodinated PVP, against human spermatozoa via the use of the Sander-Cramer test and the cervical mucus penetration test. DESIGN: Solutions of PVP-nonoxynol-9 and iodinated PVP-nonoxynol-9 containing nonoxynol-9 whole molecule (oligomers 1 to 18) and its isolated fractions (oligomers 8 to 10, 4 to 6, and 1 to 3) at various concentrations (microgram/mL) were prepared via serial dilutions. Spermicidal solutions were mixed with human semen to determine the minimal lethal dose (microgram/mL). In the Sander-Cramer test, the lethal dose was reported as the minimal dose capable of killing spermatozoa within 20 seconds. In the cervical mucus penetration test, the lethal dose was reported as the minimal dose capable of preventing penetration of spermatozoa into cervical mucus beyond the second millimeter length of the capillary. SETTING: Andrology laboratory, University of Kentucky, Lexington, Kentucky. PATIENT(S): Normospermic male donors. MAIN OUTCOME MEASURE(S): Spermicidal lethal dose determination of various nonoxynol-9 preparations containing the whole nonoxynol-9 molecule and its isolated fractions coprecipitated with PVP or iodinated PVP. RESULT(S): The use of PVP increased the aqueous solubility of the nonoxynol-9 formulations containing oligomers 1 to 18 and 8 to 10 slightly. The coprecipitation of the nonoxynol-9 formulations containing nonoxynol-9 oligomers 4 to 6 and 1 to 3 with PVP significantly increased their solubilization and spermicidal action in vitro. Moreover, the incorporation of iodine significantly decreased the minimal nonoxynol-9 dose required for complete killing of spermatozoa in preparations containing nonoxynol-9 oligomers 4 to 6 and 1 to 3. CONCLUSION(S): Incorporation of all three components tested in this study (PVP, nonoxynol-9, and iodine) enhanced the efficiency of the spermicidal preparations, especially for nonoxynol-9 preparations containing nonoxynol-9 oligomers 4 to 6 and 1 to 3.

Cervix Mucus↗

PubMed1995

Frozen-thawed bovine spermatozoa diluted by slow or rapid dilution method: measurements on occurrence of osmotic shock and sperm viability.

This study was undertaken to investigate the occurrence of osmotic shock, sperm viability and membrane functional status of frozen-thawed bovine spermatozoa during a short-term incubation period (2 h) in vitro after dilution by 2 methods. Frozen semen from 10 bulls (0.5-ml plastic straws, 7% glycerol) was thawed and diluted by slow or rapid dilution method with Ham's F-10 medium containing 0 or 7% glycerol and assessed for sperm motion parameters, percentage of spermatozoa with coiled tails and reactivity to the hypoosmotic swelling (HOS; percentage of spermatozoa swelling) test at 60 min intervals during a 2 h incubation period (37 degrees C). Post-thaw sperm viability, as reflected by percentage and grade of motility (0 to 4) did not differ between the 2 dilution methods (P > 0.05) at the beginning of incubation (Time 0). However, differences were apparent (P < 0.05) as the incubation time increased. Slow dilution with medium containing 0% glycerol caused less increase (P < 0.05) in percentage of spermatozoa with coiled tails; Moreover, these spermatozoa showed greater reactivity to the HOS test. When contrasting slow vs rapid dilution methods, the occurrence of osmotic shock was less frequent, and response to the HOS test was greater for spermatozoa diluted slowly, regardless of the glycerol content of the incubation medium. Rapid deglycerolization of frozen-thawed bovine spermatozoa in a single step, induces damage which is not detected on the basis of spennatozoal motility but is clearly evident after several hours of incubation by using the HOS test to detect damage.

Journal Article↗

PubMed1995

Epididymal spermatozoa: recovery and subsequent improvements of mouse epididymal spermatozoa via the SpermPrep filtration method.

This study was designed to determine the effects of Sephadex filtration (SpermPrep method) on the separation of viable motile, morphologically normal mouse epididymal spermatozoa and to study the viability of the recovered spermatozoa over a 3 hr incubation period. Spermatozoa were harvested from the caudae epididymides (5 animals per run or replication; n = 10) following bilateral testicular excision and incubated in 2-ml of Test-Yolk buffer (TYB) at 37 degrees C for 15 min. The specimen was then split into 2 aliquots, with Alquot 1 as the control and Aliquot 2 used for filtration. SpermPrep I column was employed according to the manufacturer's specifications (ZBL, Inc., Lexington, KY, USA) using TYB. During filtration (10 min), different fractions were obtained: first 5 min (Sample 1) and second 5 min (Sample 2). The filtered fractions were evaluated and incubated at 37 degrees C and assessed for percentage and grade of motility (0-4) every 30 min for 3 hr. Filtration resulted in a significant improvement in percentage and grade of motility (91.5% and 3.0 vs. 76.5% and 2.5, respectively). The results point out very clearly that the filtration via the SpermPrep method improved the percentage and grade of motility (p < 0.05) but not the percentage normal morphology of the spermatozoa. Also the SpermPrep I enabled the recovery of 45% (8.3 x 10(6) spermatozoa) of the total spermatozoa processed in the control aliquot (18.4 x 10(6) spermatozoa) which is consistent with previous observations. Most importantly, filtered spermatozoa incubated for 3 hr showed greater percentage and grade of motility than the control spermatozoa (63% and 1.66 vs. 39% and 0.82, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

A method of short-term cryostorage and selection of viable sperm for use in the various assisted reproductive techniques.

The objective of this study was to determine if spermatozoa, following short-term cryostorage at 5 degrees C in Test-Yolk buffer (TYB; ZBL, Inc., Lexington, KY, USA), could be recovered and improved via the SpermPrep filtration method and to assess the possibly enhanced fertilizing capacity of the selected spermatozoa. Semen specimens from 20 men were collected, evaluated, diluted 1:1 (v/v) with TYB, divided into aliquots and cooled to 5 degrees C for 24 and 48 hr. Semen samples were assessed for volume, sperm count, percentage and grade of motility, percentage of morphologically normal spermatozoa and outcome of the sperm penetration assay (SPA). After storage, aliquots were rewarmed at 37 degrees C, centrifuged, and the pellet was resuspended in 1.0 ml of SpermPrep media (ZBL, Inc.). Following 15 min of incubation, the rewarmed spermatozoa were filtered via the SpermPrep I filtration column (ZBL, Inc.) and assessed accordingly. The results obtained in this study indicate that the short-term cryostorage procedure yielded spermatozoa of adequate qualitative characteristics when compared to the fresh spermatozoa. Furthermore, filtration of rewarmed specimens yielded spermatozoa of significantly higher qualitative characteristics and superior fertilizing capacity following a short-term cryostorage period in TYB when compared to fresh and rewarmed spermatozoa (p < 0.05). This method of short-term cryostorage in TYB and selection of superior spermatozoa via the SpermPrep filtration method could further enhance the fertilizing ability of patients who produce spermatozoa characterized by deficient capacitation, acrosome reaction and subsequent fertilization.

Cryopreservation↗

PubMed1994

Improvements and short-term viability of mouse epididymal spermatozoa recovered through the Spermprep filtration method.

This study was designed to determine the effects of Sephadex filtration (SpermprepI method) on the separation of motile, morphologically normal, mouse epididymal spermatozoa and to study the viability of the recovered spermatozoa over a 3-h incubation period. Spermatozoa were harvested from the caudae epididymie (5 animals per run or replication; n=10) following bilateral testicular excision, after which they were incubated in 2-ml of Test-Yolk buffer (TYB) at 37 degrees C for 15-min. The specimens were then split into 2 1-ml aliquots, with Aliquot 1 as the control and Aliquot 2 as the filtered sample. The SpermprepI column was employed according to the manufacturer's specifications using TYB. During filtration (10-min), 2 different fractions were obtained: first 5-min (Sample 1) and second 5-min (Sample 2). The 2 fractions were evaluated and incubated at 37 degrees C and assessed for percentage of motility and grade of motility (0 to 4) every 30-min for 3-h. Filtration resulted in a significant improvement in the percentage and grade of motility (91.5% and 3.0 vs 76.5% and 2.5, respectively). The results indicate that filtration with the SpermprepI method improved the percentage and grade of motility (P<0.05) but not the percentage of normal morphology of the spermatozoa. In addition, the SpermprepI method enabled the recovery of 45% (8.3x10(6) spermatozoa recovered) of the total number of spermatozoa processed in the control aliquot (18.4x10(6) spermatozoa), which is consistent with previous observations. Most importantly, filtered spermatozoa incubated for 3-h showed a greater percentage and grade of motility than the control spermatozoa (63% and 1.66 vs 39% and 0.82, respectively. The SpermprepI filtration method selected a higher proportion of quality spermatozoa, which also displayed significant long-term motility (longevity) during in vitro incubation.

Journal Article↗

PubMed1994

The hypoosmotic swelling test: Its employment as an assay to evaluate the functional integrity of the frozen-thawed bovine sperm membrane.

The objective of this study was to determine the effectiveness of the hypoosmotic swelling (HOS) test together with the supravital test as a means of evaluating the functional integrity of frozen-thawed bovine sperm membrane. A solution consisting of equal parts of fructose and sodium citrate was prepared and the osmolality varied from 50 to 300 mOsm/L. From these various solutions under study, the 100 mOsm/L solution resulted in a maximal number of clearly identifiable swollen spermatozoa. The results from the supravital test indicated that the HOS solution preserved the integrity and prevented excessive lysis of the sperm membrane during the assay. A good correlation was found between the percentage of motile spermatozoa and spermatozoa that reacted to the HOS test (r = 0.73) and between the percentage of sperm with intact membranes and HOS reactive sperm (r = 0.81). Spermatozoa showing swelling of the entire tail region accounted for more than 60% of the total swelling for the HOS solution at 100 mOsm/L. The results obtained in this study indicate that frozen-thawed bovine spermatozoa did react to the HOS test. This technique could prove useful in studies involving the function of the sperm membrane and could possibly predict the sperm's ability to fertilize.

Journal Article↗

PubMedDate not supplied

Assessment of two devices for in vitro preparation of human sperm.

The aim of the study was to assess and compare the efficiency of the ZSC-II versus the Sperm Select techniques in preparing human sperm from normozoospermic patients for use in intrauterine insemination and other assisted reproductive technologies. Twenty-five patients were included in the study. Semen was collected at intercourse and processed via 2 sperm preparation methods. Recovery of motile sperm and other sperm qualitative measurements were evaluated before and after ZSC-II and Sperm Select sperm preparation. Sperm qualitative measurements were not significantly different after the ZSC-II and Sperm Select procedures (p > .05). Differences (p < .05) were noted between the 2 procedures in the number of sperm recovered. A higher survival rate (longevity test, 72 h) was observed after ZSC-II sperm preparation and recovery. The ZSC-II procedure yielded higher total motile sperm than the Sperm Select. The superiority in longevity may suggest possible advantages in obtaining higher fertilization and pregnancy rates.

Fertilization in Vitro↗