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Biomedical subjects

A King

Publications and source records attributed to A King.

At least 55 records · Page 3Linked to original sources
PubMed2001

Influenza revaccination of elderly travelers: antibody response to single influenza vaccination and revaccination at 12 weeks.

The antibody response to a single influenza vaccination and the effect of influenza revaccination was assessed in healthy elderly persons. Travelers > or =65 years old who had received influenza vaccine before travel were enrolled in the study and were offered a second vaccination after 12 weeks. Geographic and age-matched control subjects received a single vaccination. A second influenza vaccination was not associated with increased adverse effects. There was no significant difference between log(10) hemagglutinin-inhibiting (HI) antibody titers or an HI antibody titer > or =1:40 (considered to be protective) in 28 control subjects and 28 revaccinated travelers for any antigen. Probable protection for influenza A antigens remained high 24 weeks after a single immunization and revaccination (A/Sydney/05/97 [H3N2], 92% and 96%, and A/Beijing/262/95 [H1N1], 80% and 96%, respectively). Response to B/Harbin was less throughout the study. A/Sydney antibody titer was lower with more times vaccinated in the previous 5 years. Therefore, a second vaccine did not enhance the immune response.

Aged↗
PubMed2001

Paternal monoallelic expression of PEG3 in the human placenta.

Genomic imprinting is the phenomenon whereby mono-allelic expression of certain genes occurs depending on their parental origin. The observation that imprinting only occurs in placental mammals has led to the suggestion that it may play a role in this form of reproduction. In the present study we have investigated the pattern of expression of the human PEG3 gene in the early to term placenta, as well as the uterus and ovary, using RT-PCR, northern blot and in situ hybridization. A comparison is made with the expression of Peg3 in the mouse by histochemical staining in betageo knock out mice. We have demonstrated high levels of PEG3 in the human placenta and have localized the signal to the layer of villous cytotrophoblast cells. In contrast, the pattern of expression of Peg3 in the mouse placenta is less restricted, the message being present in all trophoblast populations. Thus, expression of PEG3/Peg3 in the human and mouse placenta is not directly comparable. We have also detected PEG3 message in the ovarian stroma. We have sequenced the human PEG3 gene from exon 3 to exon 9. By utilizing a polymorphism detected in exon 9, we have established that only the paternal allele is expressed in human placenta. Human PEG3 is therefore maternally imprinted as in mouse.

Amino Acid Sequence↗
PubMed2001

Safety and immunogenicity of attenuated dengue virus vaccines (Aventis Pasteur) in human volunteers.

A randomized, controlled, double-blinded study was conducted to determine safety and immunogenicity of five live attenuated dengue vaccines produced by Aventis Pasteur (AvP). The study was completed with 40 flavivirus non-immune volunteers: five recipients of each monovalent (dengue-1, dengue-2, dengue-3, or dengue-4) vaccine, ten recipients of tetravalent (dengue-1, dengue-2, dengue-3, and dengue-4) vaccine, and ten recipients of vaccine vehicle alone. All vaccines were administered in a single subcutaneous dose (range, 3.6-4.4 log(10) plaque forming units). No serious adverse reactions occurred in volunteers followed for 6 months after vaccination. Five vaccine recipients developed fever (T > or = 38.0 degrees C), including four tetravalent vaccinees between days 8 and 10 after vaccination. Dengue-1, dengue-2, dengue-3, or dengue-4 vaccine recipients reported similar frequency of mild symptoms of headache, malaise, and eye pain. Tetravalent vaccinees noted more moderate symptoms with onset from study days 8-11 and developed maculopapular rashes distributed over trunk and extremities. Transient neutropenia (white blood cells < 4000/mm3) was noted after vaccination but not thrombocytopenia (platelets < 100,000/mm3). All dengue-3, dengue-4, and tetravalent vaccine recipients were viremic between days 7 and 12 but viremia was rarely detected in dengue-1 or dengue-2 vaccinees. All dengue-2, dengue-3, and dengue-4, and 60% of dengue-1 vaccine recipients developed neutralizing and/or immunoglobulin M antibodies. All tetravalent vaccine recipients were viremic with dengue-3 virus and developed neutralizing antibodies to dengue-3 virus. Seven volunteers also had multivalent antibody responses, yet the highest antibody titers were against dengue-3 virus. The AvP live attenuated dengue virus vaccines are safe and tolerable in humans. The live attenuated tetravalent dengue vaccine was most reactogenic, and preferential replication of dengue-3 virus may have affected its infectivity and immunogenicity.

Adolescent↗
PubMed2001

Involving consumers in designing, conducting, and interpreting randomised controlled trials: questionnaire survey.

OBJECTIVE: To assess the extent to which consumers are involved in the work of clinical trial coordinating centres in the United Kingdom and the nature of consumers' involvement in randomised trials coordinated by these centres. DESIGN: National surveys using structured questionnaires with some open ended sections. SETTING: 103 clinical trial coordinating centres in the United Kingdom identified through a database assembled in 1997 by the NHS clinical trials adviser. PARTICIPANTS: Named contacts at 62 coordinating centres and investigators in 60 trials that were identified as involving consumers. MAIN OUTCOME MEASURES: Number of coordinating centres and number of trials in which consumers were involved and the nature of consumers' involvement. RESULTS: Of the 62 eligible centres, 23 reported that consumers had already been involved in their work, and most respondents were positive about this involvement. 17 centres planned to involve consumers. 15 centres had no plans to involve consumers, but only four of these considered such involvement irrelevant. Responses from investigators about the 48 individual trials were mostly positive, with respondents commenting that input from consumers had helped refine research questions, improve the quality of patient information, and make the trial more relevant to the needs of patients. CONCLUSIONS: Consumer involvement in the design and conduct of controlled trials seems to be growing and seems to be welcomed by most researchers. Such involvement seems likely to improve the relevance to consumers of the questions addressed and the results obtained in controlled trials.

Humans↗
PubMed2001

Cutaneous transfection and immune responses to intradermal nucleic acid vaccination are significantly enhanced by in vivo electropermeabilization.

Naked DNA injection with electropermeabilization (EP) is a promising method for nucleic acid vaccination (NAV) and in vivo gene therapy. Skin is an ideal target for NAV due to ease of administration and the accessibility of large numbers of antigen-presenting cells within the tissue. This study demonstrates that in vivo skin EP may be used to increase transgene expression up to an average of 83-fold relative to naked DNA injection (50 microg DNA per dose, P < 0.005). Transfected cells were principally located in dermis and included adipocytes, fibroblasts, endothelial cells, and numerous mononuclear cells with dendritic processes in a porcine model. Transfected cells were also observed in lymph nodes draining electropermeabilized sites. A HBV sAg-coding plasmid was used to test skin EP-mediated NAV in a murine model. Analysis of humoral immune responses including immunoglobulin subclass profiles revealed strong enhancement of EP-mediated NAV relative to naked DNA injection, with a Th1-dominant, mixed-response pattern compared to immunization with HBV sAg protein that was exclusively Th2 (P = 0.02). Applications for these findings include NAV-based modulation of immune responses to pathogens, allergens, and tumor-associated antigens and the modification of tolerance.

Adipocytes↗
PubMed2001

A simple comet assay for archived sperm correlates DNA fragmentation to reduced hyperactivation and penetration of zona-free hamster oocytes.

OBJECTIVE: To correlate sperm variables with sperm DNA fragmentation, as assessed by using a modified alkaline comet assay for sperm smears. DESIGN: The comet assay was adapted for fixed sperm smears (59 cases), and the level of DNA fragmentation was determined. SETTING: Clinical and academic research environment. PATIENT(S): 59 patients undergoing fertility treatment. INTERVENTION(S): Sperm samples leftover from IVF procedures were fixed and processed for the comet assay. MAIN OUTCOME MEASURE(S): Sperm head DNA density and sperm variables. RESULT(S): A correlation was observed between increased sperm head DNA fragmentation and decreased penetration of zona-free hamster oocytes. Heat-induced hyperactive motility decreased as DNA fragmentation increased. The DNA fragmentation did not correlate with percentages of intact acrosome, normality, maturity, and strict normal morphology. CONCLUSION(S): The advantages of the comet assay for archived cells include simplicity, low intraassay coefficient of variation, and low performance cost; in addition, DNA analysis can be carried out at leisure. Low DNA damage was associated with higher hyperactivation and oocyte penetration, suggesting that failed fertilization was linked to compromised DNA integrity in the sperm. Exploration of compounds to repair damaged DNA is warranted.

Acridine Orange↗
PubMed2001

Effects of testosterone replacement on a male professional singer.

Testosterone has been known to play an important role in the development of the postpubertal male voice for many centuries. In fact, the prevention of pubertal development of the voice by castrating young male singers was a well-known practice, especially in Italy beginning in the sixteenth century. The "castrati" were well known for their clear, high-pitched voices. Because of the resulting small larynx and vocal folds, castrati apparently produced a distinctive resonance as well as the high pitch, which cannot be matched even by the counter tenors of today. Busy voice labs occasionally see males with sex hormone deficiencies secondary to chromosomal or gonadal problems. This is a presentation of an unusual patient who was a trained tenor singer and was found to have hypogonadism on a premarital health examination. Administration of replacement testosterone resulted in significant vocal register and voice quality changes.

Adolescent↗
PubMed2001

Updating quality control assays in the assisted reproductive technologies laboratory with a cryopreserved hamster oocyte DNA cytogenotoxic assay.

PURPOSE: Despite advances in assisted reproduction, there is no progress in quality control bioassays. The objectives were to develop a comet assay to measure DNA fragmentation in thawed cryopreserved oocytes and compare this assay with one-cell mouse embryo bioassay. METHODS: Thawed hamster oocytes from a commercial source were incubated in culture media with either 0-, 50-, or 100-microM hydrogen peroxide, or, in media exposed to different contact materials and unknown proficiency analytes. Incubation time was 1.5 h at 37 degrees C. The oocytes were dried, fixed, stained with acridine orange, embedded in a mini-agarose layer and electrophoresis was carried out. Fluorescent images were analyzed. The results were compared with standard one-cell mouse assay data. RESULTS: The 100-microM hydrogen peroxide treatment caused greatest DNA fragmentation in the hamster oocytes at Hours 1 and 2. A dose response was observed. Intraassay coefficient of variation was 5.7%. Only one of the five materials tested passed both assays. The data for the unknown proficiency analytes were similar for both assays. CONCLUSIONS: The oocyte comet assay demonstrated DNA fragmentation in the presence of toxic substances. The detection of toxicity in two materials that passed the mouse bioassay suggested increased sensitivity in the new assay. The oocyte comet assay and the mouse bioassay results matched in the proficiency test. However, more studies are still needed to determine optimal sensitivity.

Animals↗
PubMed2001

Cryopreservation of human cumulus cells for co-cultures and assessment of DNA damage after thawing using the comet assay.

PURPOSE: Cumulus cells have been shown to be beneficial for blastocysts formation in co-cultures but information on cumulus cryopreservation is lacking. The objective was to use the fixed cell comet assay to analyze for DNA damage in cumulus cells after cryopreservation. METHODS: Discarded cumulus cells from follicular aspirates obtained during assisted reproduction procedures (N = 4 cases) were pooled and cryopreserved in either 40% ethylene glycol and 0.5 M sucrose, 12:20% glycerol-egg yolk medium, 28% glycerol hypoosmolar medium or control medium. The cells were processed and stored in liquid nitrogen for 48 h. The thawed cells were smeared on glass slides, fixed, stained with acridine orange, embedded in a mini-agarose layer, and electrophoresis carried out. Fluorescent images were analyzed. RESULTS: The cumulus tail moment, a calculated index of DNA damage, was significantly lower for each of the three cryoprotectant when compared with the control. The two cryoprotectants containing glycerol were associated with higher cumulus cell viability. However, the glycerol-egg yolk combination yielded the highest cell viability. CONCLUSIONS: The cumulus comet assay demonstrated similar DNA integrity in cells frozen in each of the three cryoprotectants. The glycerol-egg yolk medium had the highest cell viability with little or no DNA damage after freeze-thaw. More studies are needed to examine the long-term effect of the cryoprotectants on thawed cumulus cell viability.

Acridine Orange↗
PubMed2001

Oocyte comet assay of luteal phase sera from nonpregnant patients after assisted reproductive procedures.

PURPOSE: Serum factors in patients with recurrent spontaneous abortions (RSA) inhibit mouse embryo development in vitro. Serum factors affecting DNA integrity remain to be tested. The null hypothesis was that patient sera do not affect DNA integrity. The objectives were (a) to use the oocyte comet assay to assess DNA damage after exposure to patient sera and (b) to determine the effect of sera from gravidity 0 parity 0 patients to induce DNA apoptosis. METHODS: Luteal phase sera were drawn 1 week after embryo transfer following assisted reproductive procedures. Frozen-thawed hamster zona intact oocytes at metaphase II were incubated in groups of eight in either control medium or medium supplemented with 50% patient serum for 1.5 h at 37 degrees C in room air. The oocytes were fixed, stained in acridine orange, embedded in agarose, lysed, and alkaline electrophoresis performed. The intensities of the digitized fluorescent images were analyzed. RESULTS: The sera of nonpregnant patients (64%) caused significant fragmentation of hamster oocyte DNA when compared with pregnant patient sera. This difference was also observed when adjusted for patient age. Sera of patients that had never been pregnant also resulted in oocyte DNA fragmentation. CONCLUSIONS: The results suggested that sera from patients that did not conceive contained factors that did not support cell growth by causing DNA fragmentation and apoptosis. The level of the apoptotic factors varied from cycle to cycle. However, more studies are needed to determine if the sera factors actually reach the uterine environment to cause the undesirable effects.

Abortion, Habitual↗
PubMed2001

Ultrastructural examination is essential for diagnosis of papillary meningioma.

AIMS: Papillary meningioma is a rare meningeal tumour. To date only a few cases have been reported and their immunohistochemical features have not been fully documented. METHODS AND RESULTS: A 49-year-old woman presented with a 2-month history of headaches and memory disturbance. CT and MRI imaging showed an enhancing pineal mass with extension into the occipital lobes and invasion of the splenium. At surgery, the tumour was found to be tough and vascular with a well-defined capsule. No recurrence was noted 19 months after the operation. In another case a 44-year-old woman was admitted with 1-month history of headaches, poor memory, imbalance and diplopia. CT scan showed a large hyperdense, uniformly, enhancing mass within the middle cranial fossa at the petrous ridge. The tumour recurred 19 and 25 months after first resection. The histology of both tumours was similar. The neoplasms contained polygonal cells with a moderate amount of cytoplasm, rounded regular nuclei and distinct cell borders. The cells were arranged radially around the blood vessels (perivascular pattern) and a papillary pattern was seen only focally. Mitotic figures were moderately frequent. Immunohistochemistry showed that both tumours were immunoreactive to vimentin and NSE, whereas GFAP, CAM5.2, EMA, S100 protein and synaptophysin were negative. Electron microscopy revealed interdigitating cell processes, desmosomes and intermediate filaments. CONCLUSIONS: The histological and immunohistochemical features of these two tumours are complex and difficult to interpret. Although papillary meningiomas were considered in our initial differential diagnosis, the final conclusion was possible only when the ultrastructural features were revealed.

Biopsy↗
PubMed2001

A comparison of heat-induced hyperactivation in patients' sperm after colloid or pentoxifylline wash methods.

OBJECTIVE: Our purpose was to compare kinematic parameters of human sperm after processing through two different wash methods and 40 degrees C heat treatment. STUDY DESIGN: Sperm specimens (N = 169 cases) were washed by either colloid or pentoxifylline wash methods, and the motility parameters were measured at either 37 degrees C or 40 degrees C at baseline (0 hours) and after 4 hours. Five randomly selected washed specimens with matching 37 degrees C (control) or 40 degrees C heat treatments were assessed for changes in a sentinel gene. RESULTS: The percentage of sperm hyperactive motility was >5 times higher after the 40 degrees C heat treatment, in comparison with the 37 degrees C treatment, for both the colloid- and the pentoxifylline-washed sperm. The percentages of total motility and progression were equally enhanced in heated sperm for the two wash methods. No changes were detected in the sentinel gene with the heat treatment. CONCLUSION: Sperm cells mildly heated at 40 degrees C responded with greater motility, progression, and hyperactivation. The data suggest that mild heat is a stimulus for sperm function because greater sperm hyperactivation is associated with increased sperm fertilizing capacity. The absence of change in the sentinel gene in heated sperm suggests that a temperature of 40 degrees C is too low to initiate alterations in the highly condensed sperm chromatin. More studies are needed before mild heating of ejaculated sperm becomes acceptable for use in assisted reproductive technologies.

Colloids↗
PubMed2001

Human sperm deoxyribonucleic acid fragmentation by specific types of papillomavirus.

OBJECTIVE: Human papillomaviruses are present in up to 64.3% of patients' sperm. The objectives were (1) to determine human papillomavirus deoxyribonucleic acid effects on sperm deoxyribonucleic acid integrity and (2) to assess human papillomavirus differential effects on the sperm cell. STUDY DESIGN: Two-layer colloid washed sperm were exposed to E6-E7 deoxyribonucleic acid fragments generated from human papillomavirus types 16, 18, 31, 33, 6/11, or control (DQA1) for 24 hours. The motility parameters were measured and analyzed. Pilot studies were performed to develop a fixed sperm comet assay to assess deoxyribonucleic acid fragmentation. RESULTS: Significant sperm deoxyribonucleic acid fragmentation occurred after exposure to deoxyribonucleic acid of human papillomavirus types 16 and 31. Human papillomavirus deoxyribonucleic acid fragment size was not a factor. Human papillomavirus types 18, 33, and 6/11 did not compromise sperm deoxyribonucleic acid integrity. Washed sperm motility was higher in the presence of human papillomavirus deoxyribonucleic acid except for type 6/11. Amplitude of head displacement was lower for human papillomavirus types 16 and 6/11. Sperm linearity was increased for all human papillomavirus types except type 18. CONCLUSION: Human papillomavirus type 16 and 31 deoxyribonucleic acid caused deoxyribonucleic acid breakages characteristic of apoptotic but not necrotic sperm. The data suggest that these human papillomavirus types may adversely affect subsequent embryonic development after fertilization. Sperm deoxyribonucleic acid appears to resist human papillomavirus types 18, 33, and 6/11 or repairing mechanisms occurred. Although enhanced motility was found in human papillomavirus-exposed sperm, important velocity parameters were decreased, suggesting impaired sperm function.

DNA Fragmentation↗
PubMed2001

Abstract and engaged critique in sociology: on football hooliganism.

This note is a response to a critical review of some of my own work published recently in the British Journal of Sociology but it does not reply to the specific criticisms made in that article. Rather it addresses the question of what constitutes appropriate critique in sociology by developing a distinction between abstract and engaged criticism.

Evaluation Studies as Topic↗
PubMed2001

Comet assay of cumulus cell DNA status and the relationship to oocyte fertilization via intracytoplasmic sperm injection.

This paper postulates that in the ovary, the close association between the cumulus cells and the oocytes permits the fertilizing ability of the oocytes to be determined indirectly through cumulus cell DNA status. The objective was to use a modified comet assay to analyse cumulus cell DNA and relate the data to oocyte fertilization after intracytoplasmic sperm injection (ICSI) procedures. Oocytes were retrieved (n = 15 cases) and free-floating cumulus cells were pooled and smeared on clear glass slides to dry. Meanwhile, the denuded oocytes were injected with spermatozoa and fertilization was assessed, followed by embryo transfer. The fixed cumulus cells were stained in acridine orange, coated with a mini-gel agarose layer, lysed in alkaline buffer and electrophoresis performed. Analyses of fluorescent cell images (n = 449) showed that the tail moment was positively correlated to the percentage of fertilization after ICSI (r = 0.567, P < 0.05). In contrast, there was no correlation between tail moment and number of oocytes retrieved, total ampoules used, endometrial thickness and age of patient. The results suggested that the competence of the oocytes was associated with the cumulus cell DNA status. A unique feature here was the comet assay for archived material with obvious advantages.

Adult↗
PubMed2001

The in vitro activity of daptomycin against 514 Gram-positive aerobic clinical isolates.

The in vitro activity of daptomycin was assessed in comparison with that of vancomycin and penicillin against a wide range of Gram-positive aerobic clinical isolates. MICs were determined by an agar dilution method on Mueller-Hinton agar (NCCLS/EUCAST) and on Isotonic agar adjusted to contain 50 mg/L free calcium (BSAC). Both media were enriched with 5% horse blood for fastidious organisms. Daptomycin MICs for all 172 staphylococci, including methicillin-susceptible and methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus haemolyticus, were 0.03-0.5 mg/L. For 99 of the 100 enterococci (Enterococcus faecalis, n = 50; Enterococcus faecium, n = 50), including 37 vancomycin-resistant isolates, they were 0.25-2 mg/L. For all 108 beta-haemolytic streptococci, including Streptococcus pyogenes and Streptococcus agalactiae, daptomycin MICs were 0.016- 0.25 mg/L; for 101 alpha-haemolytic streptococci, including Streptococcus pneumoniae and 'viridans' streptococci, they were 0.016-2 mg/L. For miscellaneous vancomycin-resistant isolates including Lactobacillus spp., Lactococcus spp., Leuconostoc spp., Pediococcus spp. and isolates of Enterococcus casseliflavus and Enterococcus gallinarum, daptomycin MICs were 0.03-2 mg/L; MICs for the seven isolates of Listeria monocytogenes were 0.25-4 mg/L. There was little difference between the results on Mueller-Hinton agar and on supplemented Isotonic agar The discrepant results occasionally obtained tended to be one dilution higher on supplemented Isotonic agar. Daptomycin was active (MICs < or = 2 mg/L) against all the isolates tested with the exception of one isolate each of E. faecium and L. monocytogenes (MICs = 4 mg/L). Our results indicate that daptomycin MICs are independent of methicillin and vancomycin MICs.

Anti-Bacterial Agents↗
PubMed2001

Quality assurance of antimicrobial susceptibility testing by disc diffusion.

Quality assurance is essential to ensure the quality of antimicrobial susceptibility tests by diffusion methods. Routine internal quality control testing with a range of control strains is a major part of the quality assurance process, as it facilitates monitoring of the performance of the test. Most standardized methods include tables of acceptable zone size ranges for control strains and, in addition to checking that control zone diameters are within the published ranges, rules or statistical approaches may be applied to indicate deviations from acceptable performance. If control tests indicate unacceptable performance, the source(s) of the error should be investigated and may include problems with media, antimicrobial discs, inoculum and plate reading. Participation in external quality assessment schemes provides an independent assessment of performance although the number of strains distributed in such schemes is limited. Internal quality assessment in which routine tests are repeated with the identity of the organisms blinded is a useful complementary approach to external quality assessment and may detect problem areas not highlighted by other control methods. Education is an important part of the quality assurance process. Knowledge of atypical results for different organism-agent combinations may provide warning of possibly erroneous results, and an understanding of the limitations and sources of error in disc diffusion methods contributes significantly to the recognition, resolution and avoidance of errors.

Anti-Bacterial Agents↗