M G Dodson

East Tennessee State University, Johnson City, TN, United States

Are you M G Dodson?

Claim your profile

Publications (21)46.62 Total impact

  • Source
    S C Juneja, M G Dodson
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study, the effect of preovulatory treatment with RU486, for different lengths of time and combinations of days, was shown in terms of the ova recovery, in vitro fertilization of recovered ova, in vivo fertilization and quality of fertilized ova in PMSG/hCG-primed mice. Female mice were injected with PMSG followed 48 h later by hCG to induce superovulation. Mice received RU486 (20 mg kg-1 body wt) for 1, 2, 3 and 4 preovulatory days (in different combinations). Ovulation, as judged by the number of ova recovered at 14 to 14.5 h post-hCG, was depressed (P < 0.001), and the total number of embryos recovered at 40 h post-hCG was low (P < 0.001), in mice receiving a minimum of two consecutive days' treatment (day before PMSG + day of PMSG; or day before hCG + day of hCG) of RU486 under study. Quality of ova recovered from RU486-treated animals was not affected as determined by their ability to become fertilized in vitro. In vivo fertilization, as determined by the recovery of 2-cell embryos, was suppressed significantly in mice treated with RU486 for four consecutive preovulatory days (P < 0.001). A varied degree of premature compaction was observed in 2-cell embryos immediately upon retrieval from the oviduct of RU486-treated animals, the effect being most marked in mice receiving RU486 for a minimum of two consecutive preovulatory days under study. It is suggested that premature compaction of early embryos was under the continuous influence of the luminal environment of treated animals and might be the reason for their degeneration at later stages in the reproductive tract and for a low pregnancy rate as shown by other studies. Compacted embryos decompacted within 15-30 min in vitro and led to normal blastocyst formation in vitro in RU486-free culture medium.
    Reproduction Fertility and Development 02/1995; 7(5):1243-8. · 2.58 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study was conducted to investigate the requirement for sperm processing in microsurgical subzonal placement of sperm in rabbit oocytes. Fertilization rates with standard in vitro fertilization and microsurgical subzonal sperm placement were found to be similar (56 and 55%) when sperm treated with high-ionic strength Brackett's defined medium to initiate capacitation were used. Statistically significant reductions in fertilization rates for both standard in vitro fertilization and subzonal placement were noted when twice-washed spermatozoa were used. Initiation of capacitation of spermatozoa results in higher fertilization results even when the zona pellucida is bypassed during fertilization.
    Journal of In Vitro Fertilization and Embryo Transfer 05/1991; 8(2):111-5.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Evidence is provided for the existence of platelet-activating factor (PAF)-like activity in the lipid extracts of human spermatozoa. The PAF content of human spermatozoa based on [3H]-serotonin release from washed rabbit platelets was noted to be 1.45 pmol/10(8) sperm cells in highly purified motile spermatozoa. No PAF activity was associated with the seminal fluid. Platelet-activating factor content of spermatozoa may be related to its fertility potential.
    Fertility and Sterility 03/1991; 55(2):372-6. · 4.17 Impact Factor
  • Source
    S C Juneja, M G Dodson
    [Show abstract] [Hide abstract]
    ABSTRACT: 17 beta-Hydroxy-11 beta(4-dimethylaminophenyl)-17 alpha-(1-propynyl)estra-4, 9-dien-3-one (RU486) inhibited the in vitro development of different stages of mouse preimplantation embryos under study. Two-celled embryos, morulae, and early blastocysts were obtained from B6D2F1 mice. The embryos were grown in Ham F-10 nutrient mixture (with glutamine) supplemented with sodium bicarbonate (2.1 g/L), calcium lactate (282 mg/L), and bovine serum albumin (fraction V, 3 mg/mL) at 37 degrees C in a humidified incubator supplied with 5% CO2 in air. RU486 was added to the culture medium at concentrations of 1, 5, 10, and 20 micrograms/mL. Culture medium with 0.05% ethanol served as the control. In vitro growth of embryos was assessed by the following criteria: (i) two-celled stage embryo development to blastocyst stage after 72 h, (ii) morula stage grown to blastocyst stage after 24 h, and (iii) early blastocyst stage development to hatching blastocyst after 12 h, in culture. RU486 inhibited the in vitro development of two-celled embryos, morulae, and early blastocysts at concentrations of 5, 10, and 20 micrograms/mL culture medium (p less than 0.001). The inhibitory effect of RU486 at these concentrations on the development of all the stages of embryos under study was irreversible. However, RU486 did not affect embryo development at 1 microgram/mL culture medium. The study indicates the direct adverse effect of RU486 at 5 micrograms/mL and higher concentrations in culture medium on the development of mouse preimplantation embryos in vitro, and it encourages its further investigation as a postcoital contraceptive in animal models and humans.
    Canadian Journal of Physiology and Pharmacology 12/1990; 68(11):1457-60. · 1.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Capacitation of spermatozoa is essential for fertilization. Rabbit spermatozoa are particularly difficult to capacitate in vitro and require treatment with high-ionic-strength Brackett's defined medium. Spermatozoa treated with platelet activating factor had significantly higher fertilization rates when compared with nontreated (fresh, twice washed) spermatozoa (63% vs 34%). Fertilization rates of spermatozoa treated with platelet activating factor, although higher than those of high-ionic-strength capacitated spermatozoa, were not significantly different (63% vs 57%). Spermatozoa treated with lyso-platelet activating factor, the biologically inactive form of platelet activating factor, were noted to have fertilization rates similar to those of the untreated (noncapacitated) group. These data show that synthetic platelet activating factor treatment of uncapacitated spermatozoa induces fertilization of rabbit oocytes in vitro in a manner similar to that for spermatozoa capacitated by high-ionic-strength media and significantly higher than that for untreated spermatozoa or after treatment with the biologically inactive form of platelet activating factor (lyso-platelet activating factor).
    American Journal of Obstetrics and Gynecology 12/1990; 163(5 Pt 1):1670-3. · 3.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Mixed results have been obtained in several studies using tocolysis or antibiotics individually in the treatment of premature rupture of membranes (PROM). We compared the outcomes of a management protocol consisting of tocolysis, prophylactic antibiotic administration, and documentation of pulmonary maturity with a control group treated with passive expectant management for premature rupture of membranes. There were 55 women in the treatment group and 57 women in the control group. The mean latent phase (+/- SEM) in the treatment group was 7.34 (+/- 1.25) days compared with 1.86 (+/- .431) days in the control group (P less than .001). Eighteen of 55 patients (33%) in the treatment group were electively delivered after documentation of lung maturity, contributing to a falsely lowered mean latent phase in the treatment group. Twenty-four patients in the treatment group and 6 in the control group had a latent phase of 5 days or greater (P = .00018). There were 9 postpartum infections in the control group and 10 infections in the treatment group (P = NS). There was no difference in the length of latent phase of patients treated with ceftizoxime compared with the other antibiotics used (cefoxitin, cefazolin, ampicillin), although postpartum ceftizoxime was more effective in preventing postpartum infections (1 of 28 vs 9 of 27) (P = .005). There were fewer infected neonates in the study group, but this was not significant. It appears that treatment with this protocol significantly prolongs the latent phase in patients with preterm PROM without increasing infectious morbidity.
    Journal of Perinatology 10/1990; 10(3):252-6. · 2.25 Impact Factor
  • Source
    S C Juneja, M G Dodson
    [Show abstract] [Hide abstract]
    ABSTRACT: The effect of RU 486 at different concentrations (1, 5, 10, and 20 micrograms/ml) was studied on sperm-egg interaction in vitro in B6D2F1 mice. The in vitro fertilization rate of mouse ova decreased from 77.0% (control) to 50.0%, 28.7%, and 7.5% in the presence of RU 486 concentrations at 5, 10, and 20 micrograms/ml medium, respectively (p less than 0.001). A concentration of 1 microgram/ml did not affect the fertilization rate. A progesterone concentration at equal to or double the concentration RU 486 did not reverse the inhibitory effect of RU 486 on in vitro fertilization, which suggests a progesterone-independent mechanism. Exposure of spermatozoa (for 90 minutes) or ova (for 60 minutes) to RU 486 (20 micrograms/ml) followed by washing with RU 486-free medium before coincubation did not affect the fertilization rate. The presence or absence of cumulus cells did not change the inhibitory effect of RU 486 (20 micrograms/ml) on in vitro fertilization. RU 486 at 5 to 20 micrograms/ml medium was associated with perivitelline polyspermy in nonfertilized ova and enhanced perivitelline polyspermy in fertilized ova.
    American Journal of Obstetrics and Gynecology 08/1990; 163(1 Pt 1):216-21. · 3.88 Impact Factor
  • M G Dodson, R L Deter
    [Show abstract] [Hide abstract]
    ABSTRACT: Planes frequently used to identify radiologic and abdominal ultrasonographic images such as transverse, coronal, and sagittal are generally not anatomically correct when applied to transvaginal ultrasonographic planes and images. More appropriate terminology specific for the planes imaged during transvaginal ultrasonography, such as TRANS-pelvic and AP-pelvic planes, are suggested. A TRANS-pelvic plane refers to a plane imaged when the sound beam is directed across or from side to side in the pelvis. An AP-pelvic plane refers to an image obtained when the sound beam is directed anteriorly and posteriorly.
    Journal of Clinical Ultrasound 06/1990; 18(4):239-42. · 0.70 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Two strains of mouse embryos at the four- and eight-cell stages had biopsy specimens obtained by means of two different mechanical techniques: aspiration and displacement. Embryos and biopsy specimen cells were evaluated for survival and development. Blastomere acquisition rates were significantly higher with the displacement biopsy technique; however, no difference in survival or developmental rates was found in blastomere biopsy specimens removed from either four-cell or eight-cell embryos. A maximum of one blastomere can be removed from a four-cell embryo, whereas three blastomeres can be taken at biopsy from an eight-cell mouse embryo without significantly affecting embryo development, although mouse strain differences were noted. Intact, viable, biopsied blastomeres will develop in vitro when cocultured with morphologically intact embryos. Births of live offspring after embryo biopsy are reported.
    American Journal of Obstetrics and Gynecology 05/1990; 162(4):1084-90. · 3.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Platelet activating factor is rapidly gaining acceptance as a potent mediator in many reproductive processes. This study presents data that indicate a direct role of platelet activating factor in fertilization. Platelet activating factor was shown to significantly increase (p less than 0.001) the fertilization rate of mouse oocytes in vitro. Furthermore, CV3988, an inhibitor of platelet activating factor, was noted to significantly decrease in vitro fertilization rates at 10(-5) and 10(-4) mol/L concentrations.
    American Journal of Obstetrics and Gynecology 01/1990; 161(6 Pt 1):1714-7. · 3.88 Impact Factor
  • J KIM, W ROUDEBUSH, M DODSON, B MINHAS
    Theriogenology 01/1990; 33(1):266-266. · 2.08 Impact Factor
  • Source
    S JUNEJA, M DODSON, J ROBERTSON
    Theriogenology 01/1990; 33(1):261-261. · 2.08 Impact Factor
  • Source
    Subhash C. Juneja, Melvin G Dodson
    55th Annual Meeting of The American Fertility Society, San Franscisco; 11/1989
  • [Show abstract] [Hide abstract]
    ABSTRACT: Our laboratory has recently detected the presence of platelet-activating factor (PAF)-like activity in human spermatozoa. To gain further insight into the role of PAF on the male reproductive system, this study, using videomicroscopy, evaluated the effects of synthetic PAF on the motility of human spermatozoa. Treatment of 20 human semen samples with 3.69 x 10(-7) to 3.69 x 10(-13) M PAF resulted in statistically significant increases in motility. Treatment of spermatozoa with lyso-PAF (the biologically inactive form of PAF) showed no change in motility. Treatment of spermatozoa with PAF in severely asthenozoospermic males may be of therapeutic value.
    Fertility and Sterility 11/1989; 52(4):655-8. · 4.17 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study evaluated the effect of ovum aging on the in vitro fertilizability of mouse ova. Over 1347 ova were evaluated. Serial trypsin digestion of in vitro and in vivo aged ova revealed an increase in zona digestion time (0.25% trypsin) beginning at 40 hr, which increased over a 40-hr period and resulted in the unfertilized zona becoming as "hard" as the fertilized embryo zona. In vitro fertilizability showed a rapid decrease as zona hardening occurred with loss of cortical granules as assessed by electron microscopy. These data suggest that the window of fertilizability is "closed" by a spontaneous zona reaction occurring at about 55 hr post-human chorionic gonadotropin with loss of cortical granules and zona hardening as manifested by increasing zona digestion time with 0.25% trypsin.
    Journal of In Vitro Fertilization and Embryo Transfer 05/1989; 6(2):101-6.
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study evaluated the effect of ovum aging on the in vitro fertilizability of mouse ova. Over 1347 ova were evaluated. Serial trypsin digestion of in vitro and in vivo aged ova revealed an increase in zona digestion time (0.25% trypsin) beginning at 40 hr, which increased over a 40-hr period and resulted in the unfertilized zona becoming as hard as the fertilized embryo zona. In vitro fertilizability showed a rapid decrease as zona hardening occurred with loss of cortical granules as assessed by electron microscopy. These data suggest that the window of fertilizability is closed by a spontaneous zona reaction occurring at about 55 hr post-human chorionic gonadotropin with loss of cortical granules and zona hardening as manifested by increasing zona digestion time with 0.25% trypsin.
    Journal of Assisted Reproduction and Genetics 03/1989; 6(2):101-106. · 1.82 Impact Factor
  • Source
    Biology of Reproduction 01/1989; 40(Suppl. 1):115-115. · 4.03 Impact Factor
  • G.W. Randall, B.S. Minhas, M.G. Dodson
    Theriogenology 01/1989; 31(1):243. · 2.08 Impact Factor
  • S J Fortunato, M G Dodson
    [Show abstract] [Hide abstract]
    ABSTRACT: The physiologic changes of pregnancy and the puerperium and their effect on antibiotic therapy have not received widespread attention. Pregnancy is accompanied by multiple physiologic changes, including increased uterine weight, blood volume, extracellular fluid, endometrial blood flow and renal function changes. Those changes affect therapy for endometritis since it may take several weeks for a return to the pregravid state. Preeclampsia is associated with reductions in intravascular space, increased extravascular space from edema and impaired renal function. Postpartum uterine changes may also complicate drug therapy because of poor antibiotic perfusion. The ideal antibiotic for postpartum endometritis would achieve optimal uterine tissue levels, be administered infrequently, and have adequate activity against anaerobes and minimal toxicity.
    The Journal of reproductive medicine 02/1988; 33(1 Suppl):101-6. · 0.75 Impact Factor
  • M G Dodson, S J Fortunato
    [Show abstract] [Hide abstract]
    ABSTRACT: A number of organisms, including Mycoplasma, group B Streptococcus, Bacteroides, Neisseria gonorrhoeae and Chlamydia trachomatis, have been isolated more frequently from patients in premature labor than from controls. Prophylactic antibiotic treatment in some studies lowered the incidence of prematurity. Silent chorioamnionitis has been noted in 15% of patients in premature labor. Untreated pyelonephritis is clearly associated with premature labor; however, the association of asymptomatic bacteriuria, appropriately treated pyelonephritis and premature labor is less clear. Some microorganisms have been demonstrated to produce phospholipase A2 and possibly prostaglandins, which might be the mechanism for some of the associations between premature labor and bacteria.
    The Journal of reproductive medicine 02/1988; 33(1 Suppl):87-96. · 0.75 Impact Factor

Publication Stats

219 Citations
46.62 Total Impact Points

Institutions

  • 1988–1995
    • East Tennessee State University
      • Department of Obstetrics and Gynecology
      Johnson City, TN, United States
  • 1989–1991
    • Tennessee State University
      Nashville, Tennessee, United States