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Biomedical subjects

A King

Publications and source records attributed to A King.

At least 127 records · Page 7Linked to original sources
PubMed1999

An alternative medicine study of herbal effects on the penetration of zona-free hamster oocytes and the integrity of sperm deoxyribonucleic acid.

OBJECTIVE: To analyze the effects of certain herbs on sperm DNA and on the fertilization process. DESIGN: Prospective comparative study. SETTING: Clinical and academic research environment. PATIENT(S): Donor sperm specimens. INTERVENTION(S): Zona-free hamster oocytes were incubated for 1 hour in saw palmetto (Serenoa repens), echinacea purpura, ginkgo biloba, St. John's wort (Hypericum perforatum), or control medium before sperm-oocyte interaction. The DNA of herb-treated sperm was analyzed with denaturing gradient gel electrophoresis. MAIN OUTCOME MEASURE(S): Oocyte penetration and integrity of the sperm BRCAI exon 11 gene. RESULT(S): Pretreatment of oocytes with 0.6 mg/mL of St. John's wort resulted in zero penetration. A lower concentration (0.06 mg/mL) had no effect. High concentrations of echinacea and ginkgo also resulted in reduced oocyte penetration. Exposure of sperm to echinacea purpura and St. John's wort resulted in DNA denaturation. In contrast, saw palmetto and ginkgo had no effect. Sperm exposed to 0.6 mg/mL of St. John's wort showed mutation of the BRCA1 exon 11 gene. CONCLUSION(S): High concentrations of St. John's wort, echinacea, and ginkgo had adverse effects on oocytes. Saw palmetto had no effect. The data suggested that St. John's wort, ginkgo, and echinacea at high concentrations damage reproductive cells. St. John's wort was mutagenic to sperm cells.

Animals↗
PubMed1999

Spermac stain analysis of human sperm acrosomes.

OBJECTIVE: To study the association between low percentages of intact sperm acrosomes and fertilization failures in conventional IVF procedures. DESIGN: A retrospective study. SETTING: Clinical and academic research environment. PATIENT(S): Patients undergoing treatment of infertility. INTERVENTION(S): Sperm cells were fixed and stained using the Spermac stain. MAIN OUTCOME MEASURE(S): Percentages of intact acrosomes and fertilization. RESULT(S): There was a significant association between specimens with <40% intact acrosomes and failed conventional IVF procedures. Among the 29 cases with <40% intact acrosomes, 9 cases (31%) resulted in zero penetration of the oocytes. The mean (+/-SEM) percentage of fertilization was lower in the abnormal acrosome group (43.3% +/- 6.5%) than in the normal acrosome group (64.1% +/- 5.6%). The status of the sperm acrosome was not correlated with the results of fertilization in intracytoplasmic sperm injection procedures. CONCLUSION(S): Sperm with low percentages of intact acrosomes were associated with failed fertilization. The Spermac stain was useful for assessing acrosomes and identifying possible male factor infertility problems. The results suggested that a minimum percentage of sperm with intact acrosomes are needed for fertilization to occur in vitro.

Acrosome↗
PubMed1999

Asymmetric direduction of 1,2-indanedione to cis (1S,2R) indanediol by Trichosporon cutaneum MY 1506.

Cis (1S,2R) indanediol is a potential precursor to (-)-cis (1S,2R)-1-aminoindan-2-ol, a key chiral synthon for a leading HIV protease inhibitor, Crixivan (Indinavir). A potential route to the biosynthesis of this important precursor, the microbial asymmetric direduction of 1,2-indanedione to its corresponding diol, cis (1S,2R) indanediol, was investigated. The screening of 32 yeast strains yielded Trichosporon cutaneum MY 1506 as a suitable biocatalyst. At the 2-l shake-flask scale, 1,2-indanedione (charged at 1.0 g/l) was bioconverted to cis (1S,2R) indanediol at a final bioconversion yield of 99.1% and an enantiomeric excess of >99%. When scaled up in a 23-l bioreactor, T. cutaneum produced 8.4 g of pure cis (1S,2R) indanediol, and the isolated yield of cis (1S,2R) indanediol was 52%. Purification of the scale-up also yielded 0.9 g of the more polar trans (1S,2R) indanediol diastereomer, a minor bioreduction product. Supercritical fluid chromatography analyses of the purified cis (1S,2R) and trans (1S,2S) indanediol demonstrated that the enantiomeric excesses during this bioconversion scale-up were 99% and 26%, respectively.

Journal Article↗
PubMed1999

Tenacity of exogenous human papillomavirus DNA in sperm washing.

PURPOSE: Sperm cells have been shown to take up exogenous DNA readily. The hypothesis was that sperm washing would remove exogenous viral DNA infecting sperm cells. The objective was to compare three types of sperm washing procedures for their capacity to remove exogenous human papillomavirus (HPV) DNA from infected sperm. METHODS: Prewashed sperm were equally divided and sperm in one portion were exposed to L1 HPV DNA fragments for 30 min at 37 degrees C. Untreated washed sperm served as the control. After transfection, the sperm were washed by either centrifuge, two-layer Isolate colloid wash, or test-yolk buffer procedures. Sperm parameters were measured on a Hamilton Thorn HTM-C analyzer. Sperm DNA were extracted and polymerase chain reaction (PCR) was carried out targeting the L1 consensus gene of HPV and the designated sentinel gene, 17q21 spanning the D17S855 gene. Amplified products were analyzed in 2% agarose gel electrophoresis. RESULTS: PCR analyses detected the consensus L1 HPV gene in sperm after they were processed through either of the three procedures. Controls were negative for the L1 gene. Extracted DNA were verified by PCR amplification of 17q21 spanning the D17S855 gene. Transfected sperm had higher percentages of total motility and progression compared with the control. Centrifuged, washed, transfected sperm exhibited a greater curvilinear velocity and hyperactivation. CONCLUSIONS: The data showed that washing would not remove exogenous HPV DNA from sperm cells. The viral DNA was tenaciously bound to the sperm, suggesting an internalization into the sperm. The viral DNA also increased the motility of the sperm by affecting the velocity and progression of the sperm, which suggested either an increase in metabolism, an enhancement of the calcium-regulated motility mechanism, or an artifact of PCR reagents. More studies are needed to elucidate the mechanism of DNA stimulated sperm motility.

Chromosome Mapping↗
PubMed1999

Sperm artificially exposed to antisperm antibodies show altered deoxyribonucleic acid.

PURPOSE: Our purpose was to assess sperm deoxyribonucleic acid (DNA) integrity after exposure to antisperm antibodies. METHODS: Donor semen were divided and exposed to sera containing IgG, IgA, and IgM antisperm antibodies. Untreated portions served as the control. After incubation (1 hr, 23 degrees C), the sperm were centrifuge-washed, resuspended, and incubated (23 degrees C) for 2, 5, 7, or 9 days. Acridine orange staining and kinematic parameters were measured. The sentinel (17q21 from D17S855) and beta-globin genes were amplified and analyzed using denaturing gradient gel electrophoresis. RESULTS: Sperm preexposed to antisperm antibodies had deleted sentinel gene on days 7 and 9. The beta-globin gene was intact. There were no differences in acridine orange staining. CONCLUSIONS: Sperm artificially exposed to antisperm antibodies resulted in a subtle deletion of genetic material. The DNA alteration process was slow and was undetectable at the gross level. More studies are needed to confirm the findings and determine whether DNA repair mechanisms can reverse the damage.

Acridine Orange↗
PubMed1999

Mycoplasma-mediated uptake of the exogenous human BRCA1 gene by hatching blastocysts.

PURPOSE: Biological vectors for cell transfection are mainly viral in origin, with inherent shortcomings. Mycoplasmas are ubiquitous organisms that traverse cells easily. The objective was to determine if Ureaplasma urealyticum (T-mycoplasma) would vector exogenous BRCA1 DNA into blastocysts. METHODS: Hatching mouse blastocysts (N = 70) were incubated in the presence of either viable or dead Ureaplasma urealyticum at 37 degrees C for 1 hr. The blastocysts were exposed to human BRCA1 DNA lacking homology in the mouse genome for 2 hr, followed by DNase-1 treatment and wash. Polymerase chain reaction and agarose gel electrophoresis analysis of amplified products were performed. RESULTS: The BRCA1 gene was detected in the blastocysts only when viable Ureaplasma was present. PCR analyses of control Ureaplasma and untreated blastocysts were negative. CONCLUSION: Viable Ureaplasma organisms were shown to mediate the uptake of DNA fragments into blastocysts, resulting in transgenic mouse blastocysts with a normal human BRCA1 exon 11 gene.

Animals↗
PubMed1999

Inhibition of human sperm motility by specific herbs used in alternative medicine.

PURPOSE: Our purpose was to analyze sperm motility parameters in the presence of herbs. METHODS: Washed sperm were incubated in either saw-palmetto (Serenoa repens, Permixon Sabal serrulatum), echinacea purpura, ginkgo biloba, St. John's wort (Hypericum perforatum), or control medium. Parameters were measured on a Hamilton-Thorn analyzer after 1, 4, 24, and 48 hr at 37 degrees C. RESULTS: Sperm motility was inhibited at the high concentration (0.6 mg/mL) of St. John's wort. Curvilinear velocities and beat cross frequencies also decreased, but not hyperactivation. High-concentration saw-palmetto, echinacea, or gikgo inhibited motility at 24 and 48 hr. CONCLUSIONS: A potent inhibition of sperm motility was seen in St. John's wort unrelated to changes in pH. Furthermore, sperm viability was compromised in St. John's wort, suggesting a spermicidal effect. Metabolic changes were observed in saw-palmetto-treated sperm. High-concentration echinacea purpura interfered with sperm enzymes. Ginkgo did not have an antioxidant effect on sperm motility.

Cell Survival↗
PubMed1999

Molecular studies of trophoblast HLA-G: polymorphism, isoforms, imprinting and expression in preimplantation embryo.

There is considerable interest in human HLA-G arising from the observation that it is expressed selectively on the surface of extravillous trophoblast, the fetal cell population directly in contact with the mother. We investigated several aspects of the molecular biology of this unusual molecule. Limited polymorphism at the nucleotide level, and even more restricted variation at the amino acid level, was found in our Caucasian population. A further unusual aspect of HLA-G is the occurrence of alternatively spliced mRNAs. Spliced messages that could give rise to either membrane-bound or soluble proteins have been reported and six of these alternative forms were detected in all first trimester and term placentae, highly purified villous and extravillous trophoblast and the cell lines, JEG-3 and 221-G. An additional novel splice variant involving loss of part of the 3'-untranslated region was observed with two alleles. Using a sensitive RNase protection assay higher levels of the membrane-bound RNAs as compared to the soluble forms were detected in first trimester and term placentae as well as in JEG-3. Contrary to previous findings our term samples taken from the maternal aspect showed higher levels of both mRNA species when compared to first trimester placenta. The question of imprinting was addressed through the detection of heterozygotes both in placental tissue and, more tellingly, in the purified trophoblast cells. There was no evidence of imprinting. In addition we did not find mRNA for HLA-G in human two to eight-cell embryos or in blastocyst or in sperm samples.

Alleles↗
PubMed1999

Leptomeningeal melanoma and Creutzfeldt-Jakob disease in a patient with chronic lymphocytic leukaemia.

A 78-year-old woman with known chronic lymphocytic leukaemia (CLL) was admitted to a psychiatric unit because of rapidly declining cognitive function. Clinical examination also revealed cerebellar signs and she later became akinetic and mute. She deteriorated and died of bronchopneumonia. The histology from the post-mortem confirmed the presence of CLL in the lymph nodes and she was also found to have diffuse leptomeningeal melanoma. In addition, there was extensive prion protein deposition in the cerebral cortex, but without significant spongiosis. The astrocytosis that was present appeared superficial only. Furthermore, prion protein appeared to be co-expressed with betaA4 in the form of plaques. The patient therefore had evidence of sporadic Creutzfeldt-Jakob disease (CJD) in addition to meningeal melanoma and CLL. This case further illustrates the importance of employing prion protein immunohistochemistry in suspected cases of CJD, especially where the histology is atypical.

Aged↗
PubMed1999

The influence of the maternal uterine immune response on placentation in human subjects.

The immunological relationship between the mammalian fetus and its mother during pregnancy has been considered similar to that between a transplanted allograft and its recipient ever since Medawar (1953) first proposed the concept of the 'fetus as an allograft' in the early 1950s. Based on this analogy, it has been assumed that implantation of the fetal placenta in the uterus would be controlled similarly by a maternal immune response mediated by T-cells recognizing paternally-derived alloantigens expressed by the placenta. Surprisingly, recent evidence suggests that implantation might involve predominantly a novel allogeneic recognition system based on natural killer cells rather than T-cells (Loke & King, 1995). The cellular and molecular basis of this local immune interaction between the fetal placenta and maternal uterus is now the focus of intense research interest. Since aberrant implantation can cause a variety of clinical problems, including miscarriage, intrauterine growth retardation and pre-eclampsia, an understanding of the immunological mechanism by which this process is controlled could lead to the development of regimens to improve fetal growth and development.

Embryonic and Fetal Development↗
PubMed1999

Co-stimulation of human decidual natural killer cells by interleukin-2 and stromal cells.

At the late secretory phase of the menstrual cycle and in early pregnancy, the uterine mucosa is infiltrated by large numbers of natural killer (NK) cells with a distinctive phenotype (CD56bright CD16- CD3-) and large granular lymphocyte (LGL) morphology. Circulating CD56bright NK cells generally proliferate in the presence of interleukin-2 (IL-2), but it is clear that cofactors besides IL-2 are required for optimal response. In the bone marrow, this co-stimulating signal is provided by stromal cells. In the present study we observe that uterine CD56+ cells from early pregnancy decidua similarly proliferate vigorously when cultured with decidual stromal cells and a suboptimal dose of IL-2. This response is dependent on cell-cell contact, as no proliferation of decidual NK cells was observed when they were separated from stromal cells by a permeable cyclopore membrane. In addition, we have studied the expression of Bcl-2 by decidual CD56+ cells. Our results show that the microenvironment of the uterus is likely to have a significant influence on the proliferation and survival of uterine CD56+ cells.

CD3 Complex↗
PubMed1999

The role of trophoblast in the physiological change in decidual spiral arteries.

The remodelling of the maternal uterine spiral arteries during pregnancy, known as physiological change, is critical for the normal growth and development of the fetus. Controversy has surrounded the part played by fetal trophoblast in the transformation of these spiral arteries. To address this debate, a histological and immunochemical comparison of blood vessels from the implantation sites of human pregnancies of early gestation with uterine tissue where trophoblast was absent was performed. Results showed that true physiological change, with the features of medial necrosis and deposition of fibrinoid material, only occurred in the presence of trophoblast. In addition, it was found that subpopulations of trophoblast contribute differently in the process. Interstitial trophoblast-mediated destruction of the arterial media precedes replacement of the endothelial cells by endovascular trophoblast.

Arteries↗
PubMed1999

HLA-G in the human thymus: a subpopulation of medullary epithelial but not CD83(+) dendritic cells expresses HLA-G as a membrane-bound and soluble protein.

The human MHC class Ib gene HLA-G is transcribed and translated in different placental cell subpopulations during pregnancy. In addition to this restricted tissue distribution, HLA-G proteins were also recently detected in the thymus of HLA-G transgenic mice, as well as in some human thymic epithelial cells (TEC). There was a need to further define the phenotype of the HLA-G-expressing cells in the human thymus as well as the type of translated forms that they produce. Using several HLA-G-specific mAb and immunohistochemistry performed on cryosections of human thymi at different ages, we found that the HLA-G-expressing cells are present on medullary cells exhibiting the epithelial morphological type 6. Co-localization experiments performed by double or triple immunofluorescence staining demonstrate that these HLA-G-expressing cells express various cytokeratins, epithelial cell markers but not the CD83 dendritic cell marker. We further show by ELISA measurements that a subset of primary cultured human TEC also expresses soluble HLA-G. Therefore, HLA-G protein tissue distribution is not restricted solely to placental cells. A subpopulation of medullary TEC also expresses HLA-G both at their cell surface and in secreted form, raising the question of the functional significance of such MHC class Ib molecules. Whether thymic soluble and/or membrane-bound HLA-G contribute to inhibit NK cells or to a negative selection of autoreactive T cells which could be harmful in case of pregnancy and/or to a positive selection of viral peptides/HLA-G-restricted CD8(+) T cells remains to be demonstrated.

Adolescent↗
PubMed1999

Localization of leukemia inhibitory factor and its receptor in human placenta throughout pregnancy.

Mice in which the gene that encodes the receptor (R) for leukemia inhibitory factor (LIF) has been deleted show abnormal growth and development of the placenta. This indicates that LIF plays an important role in placental development. The expression of LIF-R and LIF was examined in human trophoblast and decidua using in situ hybridization and immunocytochemistry. LIF-R mRNA and immunoreactivity was localized in villous and extravillous trophoblast throughout pregnancy, and in endothelial cells of the fetal villi. Strong expression of mRNA encoding LIF was detected in decidual leukocytes, which are abundant at the implantation site. Extravillous trophoblast, which invades the maternal decidua, therefore expresses LIF-R as it moves past decidual leukocytes, which express LIF mRNA. The effect of LIF on cultured human trophoblast was examined in vitro. Recombinant human LIF had no effect on [3H]thymidine incorporation by purified extravillous trophoblast, nor on expression of integrins alpha1, alpha5, or beta1 by isolated trophoblast. These results identify fetal endothelial cells and all cells of the trophoblast lineage as targets for the action of LIF in human placenta. Although its effects on trophoblast are not yet clear, LIF appears to mediate interactions between maternal decidual leukocytes and invading trophoblast. LIF may also play a critical role in controlling angiogenesis in the placental villi, since human fetal endothelial cells express LIF-R, and mice lacking a functional LIF receptor gene show altered vascular development in the placenta.

Cell Division↗
PubMed1999

Effect of combined kinetic therapy and percussion therapy on the resolution of atelectasis in critically ill patients.

BACKGROUND: Some critically ill patients have difficulty in mobilizing their respiratory secretions. These patients can develop pulmonary atelectasis that may result in hypoxemia. There are some data to show that atelectasis may be prevented by turning a patient from side to side utilizing special beds. STUDY OBJECTIVES: To determine the role of kinetic therapy (KT) combined with mechanical percussion (P) in the resolution of established atelectasis of the lungs and hypoxemia in critically ill, hospitalized patients. (KT was defined as rotation of a patient along the longitudinal axis of > or = 40 degrees to each side continuously.) DESIGN: Prospective and randomized study (2:1 test to control group). PATIENTS: Twenty-four patients with respiratory failure, either mechanically ventilated or spontaneously breathing, who demonstrated segmental, lobar, or unilateral entire lung atelectasis were studied. SETTING: Medical ICU and adult respiratory ward in a county hospital in New York. INTERVENTIONS: Seventeen patients were treated with KT combined with mechanical P using a KT system (Triadyne Kinetic Therapy System; KCI; San Antonio, TX). Seven patients received manual repositioning and manual P every 2 h. Both groups received similar conventional therapy with inhaled bronchodilators and suctioning. RESULTS: Partial or complete resolution of atelectasis was seen in 14 of 17 patients (82.3%) in the test group as compared with 1 of 7 patient (14.3%) in the control group. The median duration to resolution of atelectasis was 4 days in the test group. Bronchoscopy was performed in 3 of 7 patients in the control group, but in none of the patients in the test group. A cost of $720 was incurred per patient for utilizing the specialty beds for a mean duration of 4 days. An improvement in oxygenation index occurred in the test group (change in baseline PaO2/fraction of inspired oxygen from 207.4+/-106.7 mm Hg to 318+/-100.7 mm Hg) at the end of therapy, while the control group showed a reduction over a similar duration of time (181.3+/-96.3 mm Hg to 112+/-21.2 mm Hg). CONCLUSIONS: KT and mechanical P therapy resulted in significantly greater partial or complete resolution of atelectasis as compared with conventional therapy. There was a generalized trend toward statistical significance in the improvement of oxygenation and a reduced need for bronchoscopy in the group receiving KT and P therapy.

Aged↗
PubMed1999

CD44 expression in human meningiomas: An immunocytochemical, immunohistochemical and flow cytometric analysis.

CD44 is a polymorphic family of cell adhesion molecules that has been implicated in tumour invasion and metastasis. In this comparative analysis study, we investigated the expression of the standard form of CD44 (CD44s or CD44H) in 25 early passage cultures of meningiomas and histological sections, using immunohistochemical, immunocytochemical and flow cytometry techniques. There were 20 grade I, 3 grade II and 2 grade III meningiomas in the study which also included 2 recurrent meningiomas and 1 meningioma arising some time after previous radiotherapy. Immunocytochemistry and flow cytometry results on early passage culture cells show that although the majority of the meningiomas were strongly positive for CD44H, some were only weakly positive. Immunohistochemical studies revealed a great variability in staining patterns both within individual tumours and between different tumours. Generally, the intensity varied between strong and negative, and in most tumours that were immunopositive, there was a multifocal pattern of staining. Five meningiomas did not stain at all for CD44H. Taken together, these findings suggest that generally the flow cytometry results correspond well with those of both immunocytochemical and immunohistochemical techniques, with a few exceptions. It is concluded that microenvironmental factors may be responsible for the differential expression seen with different techniques.

Adult↗
PubMed1999

Epidemic and endemic seroprevalence of antibodies to Cryptosporidium and Giardia in residents of three communities with different drinking water supplies.

This study was carried out to compare cryptosporidiosis and giardiasis seroprevalence rates in residents of three communities. Community (Com 1) uses drinking water from deep wells, community 2 (Com 2) uses surface water from a protected watershed, and community 3 (Com 3) uses surface water frequently containing Cryptosporidium oocysts and Giardia cysts. Unfiltered drinking water from each community was collected at the tap and tested for Cryptosporidium oocysts and Giardia cysts during the 12 months in which sera were collected for testing. No oocysts or cysts were detected in the water from the Com 1 deep wells; oocysts and cysts were detected intermittently in the drinking water from the other two communities. A waterborne outbreak of cryptosporidiosis occurred in a municipality adjacent to Com 3 six months into this 12-month study. Sera from residents of each of the communities were collected proportionately by month and by population size. Coded sera were tested for IgG to Cryptosporidium using a previously developed Western blotting method. The presence or absence of bands at 15-17 kD and/or 27 kD was recorded for the 1,944 sera tested. Definite bands at 15-17 kD and/or 27 kD were detected in 981 (50.5%) of the sera. A total of 33.2% of sera from Com 1 (community using deep wells) were positive using the same criteria compared with 53.5% (Com 2) and 52.5% (Com 3) of sera from the two communities using surface drinking water. Both bands (15-17 kD plus 27 kD) were detected in 582 sera (29.9%) from the three communities: 14.1% of sera from Com 1 compared with 32.7% from Com 2 and 31.5% from Com 3. These findings are consistent with a lower risk of exposure to Cryptosporidium from drinking water obtained from deep well sources. However, analysis of results by calendar quarter showed a significant (P < 0.001) increase in the number of Com 3 positive sera (compared with Com 1) following the waterborne outbreak. Without this outbreak-related observation, a significant overall difference in seropositivity would not have been seen. We also observed that in sera from the community affected by the outbreak, the presence on immunoblots of both Cryptosporidium bands appeared to be the best indicator of recent infection. Seroprevalence rates using an ELISA to detect IgG to Giardia were estimated using the same sera. Overall 30.3% (590 of 1,944) of sera were positive by the ELISA. A total of 19.1% of sera from Com 1, 34.7% from Com 2 and 16.0% from Com 3 were seropositive. Rates for both Com 3 and Com 1 did not change significantly over time. In Com 2, rates decreased significantly (P < 0.001) during the last half of the study period (third and fourth calendar quarters). The reasons for the decrease in seroprevalence in Com 2 sera are presently not known. These studies show intriguing associations between seroprevalence, outbreak-related laboratory serologic data, and patterns of parasite contamination of drinking water. Further studies are required to validate the serologic approach to risk assessment of waterborne parasitic infections at a community level.

Animals↗