PubMed Health⌕ Search

Biomedical subjects

M G Dodson

Publications and source records attributed to M G Dodson.

At least 19 recordsLinked to original sources
PubMed1991

Treatment of sperm with high-ionic strength medium increases microsurgical fertilization rates of rabbit oocytes fertilized by subzonal placement of sperm.

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.

Animals↗
PubMed1991

The presence of platelet-activating factor-like activity in human spermatozoa.

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.

Animals↗
PubMed1991

Cervical cancer: women aged 35 and younger compared to women aged 36 and older.

One hundred fifty-three patients with invasive cervical cancer were evaluated and treated at one of the two teaching hospitals of the Intergrated Ob-Gyn Residency Program of Wright State University, Dayton, Ohio, from 1 July 1983 to 30 June 1989. Sixteen patients with recurrent cervical cancer who initially had received their treatment elsewhere were excluded. Forty-one of the 137 newly diagnosed patients with cervical cancer were aged 35 years or less. This review was undertaken because of frequent reports of the increasing incidence of cervical cancer in women aged 35 and under. Some reports also reveal a worse prognosis for the younger age group. This investigation provided the opportunity to evaluate cervical cancer patients aged 35 and under and compare the results to the evaluations of women aged 36 and over. Evaluation of age, stage, presenting symptoms, number of positive lymph nodes, pap smear history, pregnancy within 1 year of diagnosis, treatment, and survival was carried out in patients aged 35 years and less and compared to their older counterparts aged 36 and over with cervical cancer.

Adult↗
PubMed1991

Role of Neisseria gonorrhoeae and Chlamydia trachomatis in intraabdominal abscess formation in the rat.

Our concept of the pathogenesis of acute salpingitis and advanced pelvic infection, such as tuboovarian abscess, is evolving. Although Neisseria gonorrhoeae and Chlamydia trachomatis are thought to play a significant role in acute pelvic inflammatory disease, other microorganisms, such as aerobes and anaerobes, have repeatedly been reported to play a significant role, also, particularly in the patient with advanced disease. A study was designed to evaluate the pathogenesis, and particularly any synergistic role, of some aerobes and anaerobes with N gonorrhoeae and C trachomatis abscess formation. Using the rat model developed by Weinstein and Onderdonk, the study demonstrated that N gonorrhoeae and C trachomatis alone do not produce abscesses. However, when combined with facultative or anaerobic bacteria, synergism with abscess formation is noted frequently. The data support the hypothesis that N gonorrhoeae and C trachomatis initiate infection and that aerobic and anaerobic bacteria act synergistically to produce abscesses. In addition, microorganisms not inoculated were found to be recruited into the infectious process. The organisms may gain access to the peritoneal cavity via the lower genital tract or from transmucosal migration from the intestinal flora.

Abscess↗
PubMed1990

Definition of anatomical planes for use in transvaginal sonography.

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.

Female↗
PubMed1990

Clindamycin therapy for Chlamydia trachomatis in women.

The population for this study consisted of 4013 sexually active women seen for family planning. Culture for Chlamydia trachomatis yielded an isolation rate of 6.1%. Women aged 16 to 25 accounted for 81.7% of the C. trachomatis infections, while those younger than 16 or older than 35 accounted for only 2.4% of the infections. Of the 246 patients whose cultures were positive for C. trachomatis, 159 (65%) were asymptomatic. The incidence of C. trachomatis was 11.2% among those with symptoms but only 6.4% among the asymptomatic group. Among 63 patients with Neisseria gonorrhoeae (who were excluded from the study), 26 (41.3%) also were infected by C. trachomatis. There were no microbiologic drug failures with erythromycin or clindamycin. Of 56 patients who enrolled in the clindamycin arm of the protocol, 48 (85.7%) completed therapy and experienced microbiologic and clinical cures. In contrast, erythromycin therapy was completed by only 25 of 57 women (43.9%) enrolled. The number of side effect failures for erythromycin was 22 of 57 (38.6%). This was more than five times the number of side effect failures for clindamycin (4 of 56, or 7.1%).

Adolescent↗
PubMed1990

Platelet activating factor enhances in vitro fertilization of rabbit oocytes.

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).

Animals↗
PubMed1990

Survival and cell acquisition rates after preimplantation embryo biopsy: use of two mechanical techniques and two mouse strains.

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.

Animals↗
PubMed1990

In vitro effect of RU 486 on sperm-egg interaction in mice.

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.

Animals↗
PubMed1990

Effect of RU486 on different stages of mouse preimplantation embryos in vitro.

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.

Animals↗
PubMed1990

Optimum therapy for acute pelvic inflammatory disease.

Neisseria gonorrhoeae is responsible for about one-third to one-half of cases of acute pelvic inflammatory disease (PID), although there is considerable geographical variation. Chlamydia trachomatis is also an important aetiological agent, and is currently isolated 4 times more commonly from the cervix than the gonococcus. However, it is now clear that acute PID is polymicrobial in aetiology. Even when N. gonorrhoeae and/or C. trachomatis are isolated from the endocervix, anaerobes such as Bacteroides fragilis, Peptococcus and Peptostreptococcus and aerobes, especially the Enterobacteriaceae such as E. coli, are also frequently isolated. Bacterial synergism, coinfection with the gonococcus and C. trachomatis and the involvement of multiple other micro-organisms including aerobes and anaerobes and antibiotic resistance make the selection of an optimal antibiotic regimen difficult. The Centers for Disease Control (CDC) recommendations first proposed in 1982 and revised in 1985 emphasise broad spectrum antimicrobial therapy including coverage of C. trachomatis. In September 1989, the CDC revised its recommendation for the treatment of acute PID. Current recommendations include the use of newer third generation cephalosporins such as ceftriaxone, ceftizoxime and cefotaxime which give excellent coverage of the gonococcus and the Enterobacteriaceae. It is still important to include doxycycline or a tetracycline to cover C. trachomatis. For patients with advanced disease or a tubo-ovarian abscess, clindamycin plus gentamicin has been the regimen of choice. Aztreonam, a new monobactam, has several advantages over gentamicin including less toxicity, more dependable blood levels and good coverage of N. gonorrhoeae and the Enterobacteriaceae.

Female↗
PubMed1990

Prolongation of the latency period in preterm premature rupture of the membranes using prophylactic antibiotics and tocolysis.

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.

Adult↗
PubMed1989

Spontaneous zona reaction in the mouse as a limiting factor for the time in which an oocyte may be fertilized.

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.

Animals↗
PubMed1989

Effects of platelet activating factor on mouse oocyte fertilization in vitro.

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.

Animals↗
PubMed1989

The effects of platelet-activating factor on the motility of human spermatozoa.

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.

Cell Survival↗
PubMed1988

Therapeutic considerations in postpartum endometritis.

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.

Anti-Bacterial Agents↗
PubMed1988

Microorganisms and premature labor.

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.

Anti-Bacterial Agents↗