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Biomedical subjects

D R Tredway

Publications and source records attributed to D R Tredway.

At least 19 recordsLinked to original sources
PubMed1995

Sperm as a noninvasive gene delivery system for preimplantation embryos.

OBJECTIVE: To determine if sperm could be manipulated to be a noninvasive transport carrier for the delivery of gene fragments to the blastocyst. DESIGN: Sperm cells carrying foreign DNA fragments from human papillomavirus (HPV) types 16, 18, 31, and 33 were allowed to migrate from one end of an artificial reproductive tube and to come in contact with hatching mouse blastocysts at the other end of the tube. The blastocysts were then washed and analyzed for the presence of the foreign DNA fragments. SETTING: Clinical and academic research environment. MAIN OUTCOME MEASURE: Detection of amplified products from transferred foreign DNA using the polymerase chain reaction and primers targeted at the E6-E7 region for different HPV types. RESULTS: Polymerase chain reaction analyses showed transference of DNA HPV type 18 to the blastocysts. Not all types of DNA fragments were transferred equally. CONCLUSION: The results suggested the possibility of using sperm as a noninvasive gene delivery system for passing on gene fragments to preimplantation embryos. It was demonstrated that certain DNA fragments were easier to deliver than others, indicating the necessity for exploring all the factors involved in the mechanism of the transference process. The study also serves to highlight the possibility of unintentional transmission of viral or bacterial DNA to the developing embryo via the sperm.

Animals↗
PubMed1994

Human papillomavirus gene sequences in washed human sperm deoxyribonucleic acid.

The present study demonstrated the presence of HPV gene sequences in Percoll-washed sperm cells using polymerase chain reaction primers targeting smaller gene regions. Up to 64% of the sperm specimens were shown to contain gene sequences indicative of the presence of HPV. Human papillomavirus type 16 was detected about twice as often as HPV type 18. The results suggest the possible role of sperm as a vector for HPV.

DNA, Viral↗
PubMed1994

White blood cells in semen affect hyperactivation but not sperm membrane integrity in the head and tail regions.

The presence of high numbers of peroxidase-positive PML in ejaculated semen significantly reduced sperm HA, an important step leading to sperm capacitation. Sperm membranes at both the head and tail regions, as assessed by the hypo-osmotic viability parameter and the hypo-osmotic sperm swelling test, respectively, were not affected by peroxidase-containing leukocytes. Sperm motility was not affected, but sperm curvilinear and straight line velocity parameters were reduced in the presence of high concentrations of leukocytes in the ejaculate. The results suggested that the effect of leukocytes on sperm was through a reduction in sperm hyperactive motility but not through alterations in the sperm head and tail membranes.

Cell Membrane↗
PubMed1994

A new concept for anastomosis of the fallopian tube: tissue reconstruction with nonpenetrating, arcuate, legged clips in the rat model.

OBJECTIVE: To evaluate the titanium Kirsch-Zhu microclip microsurgical reanastomoses of the fallopian tubes. DESIGN: Compare the reanastomoses of the rat uterine horn between Kirsch-Zhu clips (Cushman Engineering, Albuquerque, NM) (group A) and conventional suture microsurgical techniques (group B). SETTING: Microsurgery Research Laboratory, Loma Linda University Medical Center, Loma Linda, California. PATIENTS, PARTICIPANTS: Fifteen SD rats Harlan (Harlan Sprague-Dawley Corp., Indianapolis, IN) were done in groups A and B and six in control group (C). MAIN OUTCOME MEASURE: Pregnancy rate, litter size, tissue of procedure, and histologic results. RESULTS: The clip technique was shorter in procedure time and resulted in equal fertility rate and litter size. Histologically, there were less granulomatous formation and histiocytic inflammation, but muscularis thinning and fibrosis were noted with the clip. CONCLUSIONS: The Kirsch-Zhu clip has potential for application to human fallopian tube reanastomoses.

Anastomosis, Surgical↗
PubMed1994

The relationship between human sperm fertilizing capacity and histocompatibility linked antigen (HLA) alleles gene sequences.

Heterodimer membrane glycoproteins expressed from hypervariable genes located in the histocompatibility linked antigen (HLA) class II genes on chromosome 6 have been shown to induce activation of lymphocytes and are involved in human sperm binding processes. The objective was to identify an association between HLA-DQA1, -DRB1 or -DPB1 genes and sperm kinematic parameters and sperm penetration of oocytes. The results showed reduced sperm hyperactivation and decreased sperm penetration of zona-free oocytes when the HLA-DRB1 allele was present. The reduced hyperactive motility was not attributed to alterations in sperm kinematic parameters. In contrast, the HLA-DPB1 gene only affected sperm count, linearity of movement and sperm head dimensions. HLA-DQA1 had no effect on the sperm parameters. The data suggest a link between HLA-DRB1 and HLA-DPB1 genes and sperm concentration, sperm movement characteristics and fertilizing capacity.

Alleles↗
PubMed1992

Uptake of exogenous human papilloma virus L1 DNA by oocytes and detection by the polymerase chain reaction.

OBJECTIVE: The purpose of this study was to determine if oocytes were capable of taking up exogenous DNA such as human papillomaviral (HPV) DNA and evaluate the zona pellucida as a barrier to the entry of foreign DNA into the oocyte. METHODS: The experiment consisted of four groups of hamster oocytes exposed to HPV DNA fragments: Group A, zona-free oocytes (n = 5); Group B, oocytes with an intact zona pellucida (n = 5); Group C, oocytes fixed in 4% buffered formalin solution for 20 min (n = 5); and Group D, zona-free oocytes (n = 4). Group C oocytes served as an internal control to ensure adequate washing of the oocytes after incubation. RESULTS: The zona pellucida was not a barrier to foreign DNA molecules. The PCR did not detect L1-HPV and beta-globin gene sequences in the untreated hamster oocyte. Uptake of the smaller DNA fragments such as that amplified from the beta-globin region was independent of active oocyte cell processes. CONCLUSION: Oocytes cultured in vitro can passively take up exogenous DNA fragments. The results suggest a possible role of oocytes as vectors for foreign DNA.

Animals↗
PubMed1992

Sperm hyperactivation as quality control for sperm penetration assay.

The sperm penetration assay (SPA) is subject to considerable variation, and controls are needed to verify the accuracy of the results. It is proposed that sperm hyperactivation (HA) can serve as a quality control check for the SPA. The objective was to determine if there was an association between the SPA outcome and sperm HA measured at various times during the SPA procedure. The data showed a significant correlation between percent sperm HA and percent zona-free oocyte penetration by sperm preincubated for three hours prior to sperm-oocyte interaction (short preincubation). Some sperm hyperactivity was observed in liquefied raw semen samples, but this was insignificantly related to SPA results. Low correlation was observed between SPA results and sperm HA determined immediately after centrifuge washing of sperm. The results suggest that it is possible to utilize sperm HA measured immediately after the sperm-oocyte interaction period as a quality control check of SPA results.

Female↗
PubMed1992

Assessment of sperm for cryopreservation using the hypoosmotic viability test.

In summary, the hypoosmotic viability parameter was significantly correlated with the outcome of the thawed sperm motility. The prefreeze supravital staining for sperm viability and the hypoosmotic sperm swelling test were not predictive of the thawed sperm total motility. The hypoosmotic viability parameter was not correlated to the postwarmed sperm motility after refrigeration. The results indicated that the integrity of the sperm membranes at the head were more important than the tail membrane.

Cell Survival↗
PubMed1991

Identification of male-factor semen samples prior to insemination and in vitro fertilization.

Semen analyses carried out as part of the clinical in vitro fertilization or intrauterine insemination protocols provide important information that determine the type of clinical treatment of the male partner and the sperm processing method. It is postulated that the sperm of male-factor patients cannot survive hypoosmotic stress conditions because of defective sperm membrane function. To test this, 0.1 ml of semen from each of 102 patients was placed in 1.0 ml of 150 mosmol/liter eosin citrate fructose solution and incubated for 30 min at 37 degrees C. The percentage viability of the sperm cells was then determined. The results indicated that patients with two or more abnormal semen parameters had a significantly lower percentage viability while in the hypoosmotic solution (40.6 +/- 4.7%), in contrast to non-male-factor patients (69.0 +/- 1.6%). Donor sperm (N = 32) serving as controls (73.3 +/- 2.1%) had a viability in hypoosmotic solution similar to that of non-male-factor patients. The data suggest that sperm of male-factor patients are less able to survive the hypoosmotic stress conditions as shown by the percentage viability in hypoosmotic solution and emphasize the importance of using less stressful sperm processing methods for in vitro fertilization or insemination in these patients.

Cell Membrane↗
PubMed1991

Combined supravital staining and hypoosmotic swelling test.

The parameter of sperm viability in hypoosmotic solution (VHOS) provides information concerning the membrane integrity of the sperm head. The objective of this study was to determine the association between the VHOS parameter and the sperm penetration assay. The VHOS parameter correctly predicted 70.0-71.4% of the failed sperm penetration assay samples in the short duration preincubation groups. A combination of both the VHOS parameter and the hypoosomotic sperm swelling (HOS) test significantly reduced the number of false negative results. In general, a sperm sample with an abnormal VHOS result and an abnormal HOS test result would be associated with a negative sperm penetration assay. Washing by centrifugation appeared to weaken the sperm head membranes while the swim-up method selected for sperm with strong head and tail membranes. After the various processing methods unique changes in the integrity of the sperm head and tail membranes for each sperm sample may help to identify the optimal method of preparation for individual patients undergoing the newer assisted reproductive technologies such as sperm microinjection.

Cell Membrane↗
PubMed1990

Inhibition of implantation in vitro of frozen-thawed mouse embryos by the signal molecule diadenosine tetraphosphate.

The dinucleotide polyphosphate, diadenosine 5', 5'''-P(1), P(4)-tetraphosphate (Ap4A), has been identified in mammalian and non-mammalian cells as a signal molecule that initiates the process of DNA replication and cell division. The objective of this study was to determine the function of this messenger molecule in preimplantation mouse embryonic cells. Frozenthawed two-cell mouse embryos were incubated in the presence of 0, 0.1 and 1.0 mM Ap4A at 37 degrees C in moist 5% CO(2) in air mixture for 5 d. The developmental stages of the embryos in terms of hatching and implantation were evaluated. The data showed dose-dependent inhibition of blastocyst implantation; however, there were no differences observed in the number of embryos developing to the blastocyst stage. The results suggest that Ap4A neither promotes nor inhibits the development of early stage embryos except at the implantation stage, where it exerts inhibitory control.

Journal Article↗
PubMed1990

Effectiveness of stimulated menstrual cycles and Percoll sperm preparation in intrauterine insemination.

To examine the usefulness of intrauterine insemination in women with various fertility factors, we retrospectively analyzed data from women treated during 1986 and 1987. Ninety-three patients underwent 1-11 cycles of single or double procedures, for a total of 423 inseminations in 263 treatment cycles. Twenty-six patients (28%) conceived, for a 10% total pregnancy rate per cycle, with 58% of the pregnancies resulting from double inseminations per cycle. An average of two treatment cycles was required to achieve pregnancy. Eight pregnancies (31%) occurred in spontaneous cycles, while 18 (69%) occurred in stimulated cycles. While clomiphene citrate therapy was useful in anovulatory patients, it was of no benefit in ovulatory patients being treated with intrauterine insemination. Human menopausal gonadotropin therapy was of benefit in both ovulatory and anovulatory patients when combined with intrauterine insemination. The live birth rate was higher (75%) in spontaneous cycles than in stimulated cycles (44%). Semen preparation was accomplished by sperm washing in 61% of the pregnancies and by Percoll preparation in 39%. The effectiveness of the discontinuous Percoll gradient for semen preparation for insemination was suggested by a pregnancy rate of 9% per cycle. While the mean sperm count in the pregnant group was 44 million, successful pregnancy was accomplished with a double insemination of 880,000 and 1.16 million rapidly progressive sperm in the first and second inseminate, respectively. The data confirm the important role of intrauterine insemination for the treatment of infertility.

Adult↗
PubMed1989

Effectiveness of short pituitary suppression with gonadotropin-releasing hormone agonist leuprolide during induction of ovulation for in vitro fertilization.

A short suppression regimen with daily 0.5 mg leuprolide commencing the first day of in vitro fertilization (IVF) cycles was evaluated in 10 women who previously underwent similar IVF cycle without suppression. Induction of ovulation, oocyte retrieval, incubation, and embryo transfer were similar in all the cycles. Assessment included the amount of human menopausal gonadotropin (hMG) used, length of stimulation, serum estradiol and luteinizing hormone (LH) levels, number of oocytes retrieved and their quality, cleavage rate, and number of embryos. The results showed that when leuprolide was used, no endogenous LH surge was detected, and there was a significant increase in hMG injected, from 19.0 +/- 5.8 to 34.4 +/- 17 ampoules, and in estradiol levels, from 1276 +/- 470 to 2618 +/- 1084 pg/ml (mean +/- SD). In addition, there was an increase in the total oocytes retrieved from 54 to 94, their cleavage rate from 59 to 86%, and the number of embryos from 24 to 70 in the suppressed cycle. No deleterious effects were observed and there were two pregnancies in this group.

Adult↗
PubMed1989

Evaluation of the Pipelle curette for endometrial biopsy.

The Pipelle endometrial suction curette was evaluated, and its application and effectiveness were compared to those of the Novak curette for endometrial sampling during the midluteal phase. Fifty women underwent an endometrial biopsy with the Pipelle and Novak curettes. Ninety percent of the women preferred the biopsy with the Pipelle. Histologically, tissue obtained with the Pipelle was satisfactory and similar to that with the Novak. The Pipelle curette appears to be an excellent device for midluteal endometrial biopsy during an infertility evaluation.

Biopsy↗
PubMed1985

Correlation of postcoital evaluation with in vitro sperm cervical mucus determinations and ureaplasma cultures.

Fifteen trials were completed in 14 couples during an infertility evaluation. The postcoital test (PCT) was accomplished in a standardized manner. Also, standardized determinations of the sperm-cervical mucus penetration test (SCMPT) with the addition of cross-testing (X-test) utilizing bovine cervical mucus (BCM) and normal donor semen (NDS) were done. Male and female samples were also cultured for Ureaplasma urealyticum using U9-B indicator broth and A-7 agar. The PCT and SCMPT agreed in 87% (13/15) of the cases. Utilizing BCM and NDS, where possible, the causative factor was the cervical mucus in 54% (7/13); semen factor in 15% (2/13); both factors in 8% (1/13); and undetermined in 23% (3/13). U. urealyticum cultures were positive in 40% (6/15) of the cases. Analysis of the results revealed: (1) significant correlation between PCT and SCMPT (P less than 0.01); (2) no significant difference among the PCT, SCMPT, and X-test, indicating that the cervical mucus was the causative factor; and (3) no U. urealyticum correlation with the PCT or the SCMPT. Thus, laboratory SCMPT and X-test correlated with the PCT, providing additional information concerning the causative factor in infertility. The U. urealyticum status in cervical mucus and semen cannot be determined from the PCT nor the SCMPT.

Adult↗
PubMed1980

Pituitary response to LHRH in hypothyroid women.

This study was designed to characterize pituitary function in premenopausal women during hypothyroid and euthyroid periods. Six subjects with basal thyroid-stimulating hormone (TSH) levels above 10 microU/ml were studied. Estradiol (E2), prolactin (PRL), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels were measured by radioimmunoassay at 30, 15, and 0 minutes before infusion. Pituitary function was evaluated by rapid infusion of 10 micrograms of luteinizing hormone-releasing hormone (LHRH) every 2 hours for a total of 6 hours. Samples were then obtained for FSH and LH every 30 minutes for the duration of the 6-hour study. A significant elevation in basal gonadotropins was observed during the hypothyroid period regardless of basal E2 levels in all 6 subjects (P < .01). Basal PRL levels were not significahtly different during the 2 periods (P > .05). In all 6 patients pituitary sensitivity and reserve correlated significantly with basal E2 levels (P < .05), but were not altered by the hypothyroid condition. It is concluded that pituitary responsiveness to LHRH is not altered in hypothyroid women, but that chronic elevation of basal gonadotropins may in part explain the anovulation that so often accompanies this disorder.

Estradiol↗