Biomedical subjects

William C Patton

Publications and source records attributed to William C Patton.

11 recordsLinked to original sources

PubMed2006

In vitro tagging of embryos with nanoparticles.

PURPOSE: To develop an in vitro method for tagging embryos and to compare the development of the embryos after nanoparticles injection versus externally-applied nanoparticles derived from either polystyrene or polyacrylonitrile. METHODS: Each mouse 1-cell embryo (the selected test-model) was either: (a) injected by intracytoplasmic injection or (b) co-incubated with different nanoparticles at 37 degrees C, 5% CO2 in air. The embryos were assessed after 2 and 6 days of culture. RESULTS: Embryo development was similar for externally-applied polystyrene nanoparticles and control (97.6 +/- 2.7 versus 100.0 +/- 0%) but different for polyacrylonitrile nanoparticles (90.0 +/- 2.8 %) on day 2. However, the results were similar on Day 6. Injected embryos were linked to lower percent development on Day 2. Few injected embryos reached blastocyst stage on Day 6 after a brief UV-fluorescence exposure. CONCLUSIONS: Tagging embryos by external polystyrene-based nanoparticles was the better method when compared with injected nanoparticles. Larger nanoparticles in microsphere range were easier to qualitate. Inhibited hatching limited their use beyond the blastocyst stage.

Animals↗

PubMed2006

Influence of nanoparticles on morphological differentiation of mouse embryonic stem cells.

OBJECTIVE: To assess mouse embryonic stem (ES) cell viability, growth, and differentiated morphology after exposure to different concentrations of nanoparticles. DESIGN: Cell culture for 6 days. SETTING: University research laboratory. ANIMALS: Cryopreserved mouse ES-D3 (American Type Culture Collection, Manassas, VA) cells. INTERVENTION(S): ES cells were exposed to either 0 (control), 0.4, or 12.2 million/mL mixed-size fluorescent nanoparticles in culture (37 degrees C, 5% CO(2) in air) for 6 days. MAIN OUTCOME MEASURE(S): Cell viability and morphometric analysis were performed. RESULT(S): ES cells exposed to both concentrations of nanoparticles exhibited smaller cell surface area. The effect was not concentration dependent. In contrast, ES cell nucleus size was unaffected. The nanoparticles distributed into the cytoplasm, pseudopods, and the perinuclear region. ES cell viabilities were reduced 40% and 30% in the low versus high relative concentration, respectively. ES cells in low-concentration nanoparticles became mostly columnar and embryoid body shaped. However, in high-concentration nanoparticles, they differentiated toward fibroblast-like and less squamous types. CONCLUSION(S): The observed reduced ES cell surface area suggested disruption of cytoskeletal development but not nuclear organization by nanoparticles. The ring-like formation of nanoparticles around the nucleus and the resulting cell morphologies suggested nanoparticles may influence differentiation.

Animals↗

PubMed2006

Human papilloma virus DNA exposure and embryo survival is stage-specific.

PURPOSE: Human papillomavirus (HPV) has been shown to disrupt late-stage implanting embryos. The objectives were (a) to assess the development of early embryos exposed to HPV DNA and (b) to analyze the blastocyst hatching process after HPV exposure. METHODS: The study involved exposing two-cell and 4-8-cell mouse embryos to DNA fragments from either HPV type 16, type 18 or DQA1 (control). The embryos were incubated for 120 h and assessed. RESULTS: HPV 16 and 18 inhibited two-cell embryo development. In contrast, delaying the exposure of HPV DNA until the 4-8-cell stage resulted in further embryonic development. There was 25.9% less blastocyst formed with HPV 16 exposure. Additionally, there were 25.9-31.8% more degenerated embryos with HPV 16 exposure. CONCLUSIONS: The study demonstrated embryo stage-specific effects of HPV on early development. The results suggested HPV exposure was linked to two-cell embryo demise and delaying the exposure of HPV until later embryo stages permitted embryo development. HPV 16 was shown to decrease blastocyst formation while HPV 18 inhibited the blastocyst hatching process.

Animals↗

PubMed2006

A simple zeta method for sperm selection based on membrane charge.

OBJECTIVE: The objectives were: [1] to develop a simple zeta potential method for sperm isolation; and [2] to analyze the sperm maturity, morphology, kinematic, and DNA parameters. DESIGN: The phenomenon of sticky sperm adhering to slide surfaces was adapted for collecting charged sperm. SETTING: Clinical and academic research environment. PATIENT(S): Discarded colloid-washed sperm from routine laboratory testing (n = 8). INTERVENTION(S): Sperm were centrifuged in serum-free medium and collected for analyses. MAIN OUTCOME MEASURE(S): Kinematic parameters, DNA integrity, and maturity. RESULT(S): The percentages of mature (73.0% +/- 0.5% vs. control 63.5% +/- 0.5% SEM) and DNA intact sperm (85.0% +/- 0.3% vs. 69.5% +/- 0.5%) increased in the male factor subgroup. Strict normal morphology (19.3% +/- 0.1% vs. 10.0% +/- 0.1%), hyperactivation (7.0% +/- 0.1% vs. 3.6% +/- 0.1%), and progressive motility (29.1% +/- 0.1% vs. 19.9% +/- 0.1%) increased by twofold. CONCLUSION(S): The zeta method improved sperm parameters associated with increased fertilization and pregnancy after assisted reproduction procedures. Manipulation from the attaching-detaching process stimulated sperm metabolism without causing premature acrosome reactions. Total motility was unchanged suggesting a lack of association between total motility and zeta potential.

Acrosome Reaction↗

PubMed2005

Luteal phase serum cell-free DNA as a marker of failed pregnancy after assisted reproductive technology.

PURPOSE: DNA-damaging factors have been reported in patients that failed to achieve pregnancy after assisted reproductive technologies (ART). The hypothesis was that increased circulating cell-free DNA released by damaged cells could predict unfavorable conditions leading to failed ART treatment. The objective was to compare the relative concentrations of cell-free DNA in the luteal phase sera of nonpregnant versus pregnant patients. METHODS: Frozen-thawed sera (30 IVF cases) were obtained 1 week after embryo transfer. There were 16 pregnant and 14 nonpregnant cases and controls consisting of male sera (n = 8 cases). Modified isocratic capillary electrophoresis was performed and the images analyzed for cell-free DNA. RESULTS: Circulating cell-free DNA were identified in the sera of all patients. The serum concentrations of high (12 kb) and low (1 kb) molecular weight cell-free DNA were similar for both nonpregnant and pregnant patients. Male control sera had higher cell-free DNA concentrations compared with females. Evaluation of sera from a control case showed no fluctuations in cell-free DNA concentrations throughout specific days of the menstrual cycle. CONCLUSIONS: The results do not support the use of the luteal phase cell-free DNA concentration as a marker for failed pregnancies. The equal concentrations of high and low molecular weight cell-free DNA and ladder band-like gel patterns suggested cell apoptosis as the source of DNA.

Adult↗

PubMed2005

Mouse embryonic stem cells for quality control testing in assisted reproductive technology programs.

OBJECTIVE: To compare the mouse embryonic stem (ES) cell assay with the sperm motility test or 1-cell mouse embryo bioassay for embryotoxic materials. STUDY DESIGN: Cryo-preserved-thawed mouse ES-D3 cells, 1-cell mouse embryos and donor sperm were incubated for 1-4 days in culture medium exposed to a control and 4 different test materials. ES cell viability (eosin method), apoptosis (Sybr-Gold fluorescence), development of blastocysts and sperm motility parameters were measured. RESULTS: The initial viabilities of ES cell were determined to be 37.0 +/- 4.2% (n = 225) and 54.8 +/- 7.4% (n = 218) by the eosin and Sybr Gold methods, respectively. Reduced viability of ES cells in latex glove-treated medium (25.6 +/- 0.3% and 25.7 +/- 0.3% versus control, 32.8 +/- 0.2% and 33.5 +/- 1.0% by eosin or Sybr Gold, respectively, p < 0.05) was consistent with standard bioassays. However, toxicity in the syringe was detected only by the ES cell assay. The ES cell assay sensitivities were 33% and 67% (eosin and Sybr Gold methods, respectively), and specificities were 100% for both methods. CONCLUSION: Mouse ES cell assay based on Sybr-Gold asssessment was as effective as standard bioassays for detecting embryotoxicity. The results suggested that the mouse ES assay could be used for testing contact materials and DNA-modifying agents. More studies are needed to refine and enhance the sensitivity of the ES cell assay for routine use in assisted reproductive technology clinics.

Animals↗

PubMed2004

Modified isocratic capillary electrophoresis detection of cell-free DNA in semen.

PURPOSE: The objectives were: i) to analyze semen for the presence of cell-free DNA and ii) to determine the association between sperm parameters and cell-free DNA. METHODS: Cell-free DNA in semen (N = 25 cases) were detected using the modified capillary gel electrophoresis (CE) procedure. SYBR-Gold was used to stain high (12 Kb) and low (1 Kb) molecular weight DNA fragments and the images analyzed. RESULTS: The quantity of low-molecular weight cell-free DNA was positively correlated to rapid progression, curvilinear velocity (>40 microm/s), normal strict morphology and capacitation index. High-molecular weight cell-free DNA intensity index was negatively correlated to post-wash hyperactivation. Sperm concentration was not related to cell-free DNA quantity. The sperm freezing process did not increase cell-free DNA but reduced the more labile low-molecular weight cell-free DNA. CONCLUSIONS: Cell-free DNA present in semen was correlated to important sperm parameters linked to normal sperm function. The data suggested the possible use of cell-free DNA as a marker of semen quality. This study reports on the novel finding of cell-free DNA released along with sperm during each ejaculation.

DNA↗

PubMed2003

Dual fluorescence analysis of DNA apoptosis in sperm.

OBJECTIVE: The objective was to compare fluorochrome Hoechst 33342 (Ho342) with combined Ho342/propidium iodide (PI) stains for assessment of sperm quality. STUDY DESIGN: Washed donor sperm cells were incubated in either 0, 0.15, or 15 micromol/L camptothecin (CAM) or 0.37 or 3.7 mmol/L genistein (GEN) for 4 hours at 37 degrees C. The sperm cells were analyzed for cycle-independent apoptosis and necrosis by single- compared with dual-stained fluorescence microscopy to contrast the relative effectiveness of these two approaches. RESULTS: The single-stain procedure did not detect viability differences (overall 76.1% +/- 2.2% live). In contrast, the dual-stain procedure identified a dose-dependent decrease in viability and increased necrozoospermia for CAM and GEN treatments. Apoptosis was 2-fold higher with topoisomerase inhibitor treatment. CONCLUSION: The two topoisomerase inhibitors were associated with increased apoptosis and dose-dependent necrosis. The data suggested that the dual-stain combination Ho342/PI was more sensitive than the single Ho342 stain analysis and permitted quantifying the apoptosis and necrosis events in sperm.

Apoptosis↗

PubMed2002

A simple DNA disc chip in a microarray design based on modified comparative genomic hybridization for sperm DNA analysis.

OBJECTIVE: A DNA disc chip assay, based on comparative genomic hybridization, was designed to measure changes in sperm DNA intensities. The objective was to analyze the DNA integrity of hyperactive sperm cells after mild heat treatment. DESIGN: The assay based on a multiple cell comet assay was used to analyze changes in genomic DNA. Washed sperm DNA were tested on the assay and images stored in a microarray design. SETTING: Clinical and academic research environment. PATIENT(S): Frozen-thawed washed sperm from different donors (n = 7). INTERVENTION(S): Discarded sperm leftover from trial washes carried out at 37 degrees and 40 degrees C were frozen and processed for the DNA disc chip assay. MAIN OUTCOME MEASURE(S): Fluorescent intensities of DNA disc chips and sperm variables. RESULT(S): Heat treatment resulted in more than eightfold increase in sperm hyperactive motility with little degradation in DNA integrity. Sperm with low hyperactivation was associated with alterations in DNA after heat treatment. CONCLUSION(S): The DNA disc chip assay was simple, inexpensive, and permitted assisted reproduction technologies laboratories to use comparative genomic hybridization for cytogenotoxicity testing. However, the assay required manual processing, a fluorescent microscope, and computer. The data showed an association between sperm hyperactivation and DNA integrity suggesting that the hyperactivation marker may be used for selecting quality sperm for intracytoplasmic sperm injection. More studies are needed to examine temperature effects on ejaculated human sperm.

DNA↗

PubMed2002

Comparative genomic hybridization analysis of sperm DNA apoptosis after exposure to heat shock.

PURPOSE: A DNA disc chip assay based on comparative genomic hybridization (CGH) was developed to measure sperm DNA integrity. The objective was to correlate DNA integrity of heat-treated sperm with the sperm capacitation index (CI) determined from the sperm penetration assay. METHODS: Basic semen and kinematic parameters were measured (N = 6). Sperm were washed in two-layer colloid suspensions and split portions incubated at either 3 degrees C (control) or 40 degrees C for 4 h. Single-stranded DNA of heated sperm were stained in SYBR Gold and hybridized to bisbenzimide (Hoechst 33342) stained control DNA in a membrane disc. Fluorescent intensities of the discs were measured and correlation analyses with sperm parameters performed. RESULTS: Sperm CI was positively correlated (R = 0.737) with sperm DNA integrity. Two populations of sperm could be discerned: low capacitating sperm that initiated apoptosis and high capacitating sperm unaffected by heat shock treatment. The remaining parameters were not related to sperm DNA stability. CONCLUSIONS: Fragile DNA were found in a population of sperm associated with poor capacitation characteristics and apoptosis was observed after heat treatment. The results suggested that sperm dysfunction might be due to apoptotic sperm DNA resulting from an elevated temperature in the surroundings. The data suggested that the second population of high capacitating sperm induced chaperones such as heat shock proteins hsp 70 to protect against apoptosis.

Apoptosis↗

PubMed2002

Cyclooxygenase (COX)-2 and granulosa cell apoptosis in vitro.

PURPOSE: C-myc was studied in cyclooxygenase (COX)-2 associated granulosa cell apoptosis, METHODS: Granulosa cells (N = 5 cases) were incubated for 24 h in either 1 or 50 microM COX-2 inhibitor, 1 or 50 microM COX-1/COX-2 inhibitor, negative or positive controls Single primer polymerase chain reaction of c-myc exon 1 were performed. Bisbenzimide-stained control single-stranded (ssDNA) were hybridized to SYBR Gold-stained ssDNA and fluorescent images analyzed. RESULTS: C-myc was disrupted by the high-dose COX-2 inhibitor. Cell viability decreased with COX-1 and COX-2 inhibition. However, cell viability was similar for the positive control and at low-dose COX-2 inhibition. CONCLUSIONS: Inhibition of both COX-1 and COX-2 initiated apoptosis without disrupting c-myc suggesting a protective effect on c-myc. The low dosage of the COX-2 inhibitor did not disrupt c-myc and cell viability. C-myc sensitization was not part of apoptosis.

Apoptosis↗