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Biomedical subjects

Alan King

Publications and source records attributed to Alan King.

15 recordsLinked to original sources
PubMed2005

Enhancement of cellular immune response to a prostate cancer DNA vaccine by intradermal electroporation.

Recently it has become clear that more potent methods for DNA vaccine delivery need to be developed to enhance the efficacy of DNA vaccines. In vivo electroporation has emerged as a potent method for DNA vaccine delivery. In a mouse model, we evaluated the CD8(+) T lymphocyte response to a prostate cancer DNA vaccine encoding prostate-specific antigen (PSA) after intradermal electroporation. A significantly increased gene expression (100- to 1000-fold) and higher levels of PSA-specific T cells, compared to DNA delivery without electroporation, was demonstrated. Interestingly, investigation of a panel of different electroporation conditions showed that only some conditions that induce high levels of gene expression additionally induced cellular immunity. This suggests that electroporation parameters should be carefully optimized, not only to enhance transfection efficiency, but also to enhance the immune response to the vaccine. This study demonstrates the applicability of intradermal electroporation as a delivery method for genetic cancer vaccines and other DNA vaccines relying on antigen-specific T cell induction.

Adjuvants, Immunologic↗
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

Treatment of idiopathic hyperphosphatasia with intensive bisphosphonate therapy.

UNLABELLED: In a family with IH, a rare high turnover bone disease, two older siblings were wheelchair-bound with severe skeletal deformity by age 15. Their youngest affected sibling was treated intensively with intravenous bisphosphonates for 3 years. The treatment was well tolerated and prevented the development of deformity and disability. INTRODUCTION: Idiopathic hyperphosphatasia (IH, also known as juvenile Paget's disease) is a rare genetic bone disease characterized by very high bone turnover and progressive bony deformity. Inhibitors of bone resorption have been used to suppress bone turnover in the short term, but there is no published data on long-term efficacy. MATERIALS AND METHODS: An 11-year-old girl with IH, who had two severely affected older siblings, presented with progressive deformity and deafness and long bone fractures. Conventional pediatric doses of pamidronate had failed to prevent clinical deterioration or suppress bone turnover completely. Intensive bisphosphonate therapy (frequent 5-mg ibandronate infusions) was given to try and arrest progression of the skeletal disease. Growth and development, pure tone audiometry, biochemistry, radiology, densitometry (DXA), and bone histology were monitored. RESULTS: A total of 45 mg ibandronate was given over 3 years until skeletal maturity was reached (20, 15, and 10 mg for years 1-3, respectively). Ibandronate treatment was well tolerated, and biochemical markers of bone turnover suppressed to within the age-appropriate normal range There was some progression of her thoracic kyphosis, but she had no further fractures and remained mobile and active at an age when her siblings had become wheelchair-bound. A significant recovery of hearing (p < 0.01) was documented, particularly at low frequencies. Radiographs showed improvement in spinal osteoporosis and cortical bone dimensions and arrest of progressive acetabular protrusion. Areal bone density increased substantially (lumbar spine z-score from -2.2 to + 1.8). Tetracycline-labeled bone biopsy specimens were taken before and after 18 months of intensive treatment. The second biopsy showed suppression of bone turnover and a doubling of trabecular thickness, with no mineralization defect, and no osteopetrosis. CONCLUSIONS: Intensive bisphosphonate treatment prevented the development of deformity and disability and improved hearing in this child with IH. The dose of bisphosphonate, which is substantially greater than is usually used in pediatric bone disease, had no adverse effects, in particular on bone mineralization.

Alkaline Phosphatase↗
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 mutation in the gene TNFRSF11B encoding osteoprotegerin causes an idiopathic hyperphosphatasia phenotype.

Idiopathic hyperphosphatasia is an autosomal recessive bone disease characterized by deformities of long bones, kyphosis and acetabular protrusion, increasing in severity as affected children pass through adolescence. Biochemical and histological evidence indicate that there is extremely rapid bone turnover, with indices of both bone resorption and formation greatly increased. A genome-wide search, in a family with three children affected by idiopathic hyperphosphatasia, suggested linkage to a locus on the long arm of chromosome 8 (8q24). The gene TNFRSF11B encoding osteoprotegerin (OPG), which lies within this locus, was an obvious candidate, given the critical role of OPG in regulating osteoclast development. All three affected siblings were homozygous for a 3 bp inframe deletion in exon 3 of the TNFRSF11B gene, resulting in the loss of an aspartate residue. Their parents (who were first cousins) were heterozygous for the mutation. Recombinant wild-type and mutant OPG cDNAs were expressed in human epithelial kidney cells, and secreted OPG was collected from the conditioned medium. In vitro measurements of bone resorption showed that wild-type OPG suppressed bone resorption, whereas the mutant form did not, confirming this to be an inactivating mutation. This description of abnormal OPG function in humans expands the spectrum of genetic bone diseases arising from perturbations of the OPG/RANK-L/RANK system that regulates osteoclastogenesis.

Adolescent↗
PubMed2002

Differential effects of human papillomavirus DNA types on p53 tumor-suppressor gene apoptosis in sperm.

OBJECTIVE: Sperm DNA undergoes apoptotic fragmentation when exposed to HPV DNA. Details of the specific gene regions targeted by HPV in sperm are lacking. The objective of this study was to determine the integrity of exons 5 and 8 of the p53 gene in sperm exposed to HPV DNA. METHODS: Washed sperm were exposed to either HLA-DQA1 (control) or HPV type 6b/11, 16, 18, 31, or 33 DNA fragments for 24 h at 37 degrees C. The integrity of sperm p53 exons 5 and 8 was assessed using a novel DNA disc chip assay based on comparative genomic hybridization. RESULTS: Fragmentation of exon 5 occurred after exposure to HPV DNA type 18. In contrast, only exon 8 was affected by HPV type 16. HPV DNA from type 31 or 33 was without effect on the p53 exons. Sperm motility but not hyperactivation was reduced in all HPV groups. CONCLUSION: The data suggest that different HPV types preferentially degrade different exons of important genes. Decreased motility but not hyperactivation in HPV-exposed sperm suggests retention of some fertilizing capacity and the possibility of transmitting virus-destabilized genes through fertilization.

DNA Fragmentation↗
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

Human papillomavirus and blastocyst apoptosis.

PURPOSE: The effect of human papillomavirus (HPV) DNA from the E6-E7 region on the integrity of DNA in blastocyst stage embryonic cells was studied. The study design paralleled the event whereby HPV DNA from the infecting virus would target host cell DNA. The objectives were (a) to determine if the DNA of blastocysts were disrupted by the presence of HPV DNA and (b) to determine if the intensity of DNA damage was associated with the type of HPV. METHODS: This study involved superovulating female mice, mating, collecting one-cell embryos, and culturing to the expanded blastocyst stage. The blastocysts were infected with PCR-synthesized DNA fragments from either HPV type 16, 18, 31, or 33. The blastocyst DNA were analyzed by comet assay after 24 h of incubation. The fluorescent images were digitized and the pixel intensity of each blastocyst was measured. RESULTS: Only the DNA of HPV type 16 was associated with significant DNA fragmentation in comparison with the other HPV types. There was no relationship between HPV DNA fragment size and the intensity of DNA fragmentation. CONCLUSIONS: The data suggested that one mode of action of HPV type 16 was to initiate apoptosis of embryonic cells through DNA fragmentation. The effect of HPV 16 occurred rapidly within 24 h. The intensity of DNA damage was not linked to the specific type of HPV. However, the results do not rule out the other HPV types affecting embryos under conditions different from this study.

Animals↗
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

Effect of pentoxifylline on tumor suppressor and proto-oncogene apoptosis in sperm.

PURPOSE: Pentoxifylline (PTX), a methylxanthine phosphodiesterase inhibitor reduces superoxide anions responsible for DNA apoptosis. The null hypothesis was that PTX was equally effective in reducing damage to specific cell genes. The objective was to determine the DNA integrity of the BRCA1 tumor suppressor gene and the c-myc proto-oncogene after PTX. METHODS: Sperm (64 samples, 4 patients) were preincubated in either 0 (control) or 3.6 mM PTX (30 min), washed and incubated for 4 h at either 37 or 40 degrees C heat shock activation. Single primer polymerase chain reactions (PCR) were carried out on lysed sperm targeting either BRCA1 exon 11 or c-myc exon 1. Control single-stranded DNA (ssDNA) were stained with 9 microM Hoechst 33342 (blue) while PTX-treated ssDNA were stained with SYBR Gold (green). Nytran membrane discs with control ssDNA were hybridized to PTX-derived ssDNA. Fluorescent images stored in a microarray design were analyzed using ANOVA and Students' t-test for (P < 0.05) significance. RESULTS: BRCA1 integrity was higher with PTX pretreatment (93.3 + 10.4 vs. control 50.5 + 9.2; mean + SEM). In contrast, there was no difference in c-myc integrity (56.8 + 9.0 vs. 41.7 + 6.4). Sense or antisense primers gave similar DNA fragmentation results. CONCLUSIONS: The data showed PTX pretreatment protected BRCA1 but not c-myc suggesting that PTX did not equally protect different cell genes. A possible explanation was that proto-oncogenes had more fragile sites. The study involved the DNA disc chip assay to assess separate PCR-amplified sense and antisense strands. The results suggested that both strands were equally affected by PTX pretreatment.

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↗
PubMed2002

Temperature variable and the efficiency of sperm mediated transfection of HPV16 DNA into cells.

AIM: To pretreat sperm at various temperatures before exposure to human papillomavirus (HPV) 16 DNA fragments and to assess the efficiency of HPV carrier sperm to transfect cumulus cells. METHODS: Cumulus cells from follicular aspirates were obtained, pooled and divided into culture dishes containing Sybr Gold-stained HPV DNA carrying sperm that were either pretreated at 4 degree C, 37 degree C or 40 degree C (n = 5). The cells were incubated in 5% CO(2) in air mixture at 37 degree C for 24 hours. The efficiency of sperm to take up fluorescent HPV DNA was determined at hour 0. After incubation, cumulus cell viability was assessed using the eosin method and the percentages of fluorescent cumulus cells determined. RESULTS: Over half of all the cumulus cells became fluorescent with the highest percentage in the 37 degree C group. Sperm pretreated at 4 degree C had the greatest amount of HPV DNA fragments. Total sperm motility was similar for the 3 pretreatment groups. There were no differences in cumulus viability among the groups. CONCLUSION: Sperm pretreated at 37 degree C transferred the greatest amount of fluorescent HPV DNA fragments to the cumulus cells. The HPV DNA was observed in the nuclear and cytoplasmic compartments. The data suggested the possibility of sperm as a vector for the transmission of HPV DNA to the cumulus cells surrounding ovulated oocytes, which might lead to early implantation failures.

DNA, Viral↗