Identification of ammonia and volatile phenols as primary toxicants in a coal gasification effluent.
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Ammonia↗
Biomedical subjects
X Yang
Publications and source records attributed to X Yang.
Are cytokines and growth factors responsible for the detrimental effects of hydrosalpingeal fluid on pregnancy rates after in vitro fertilization-embryo transfer?
OBJECTIVE: To characterize the secretion of cytokines and growth factors in hydrosalpingeal fluid. DESIGN: Retrospective analysis. SETTING: Hospital-based infertility practice. PATIENT(S): Ten infertile women who underwent laparoscopic aspiration of their hydrosalpingeal fluid before salpingectomy or neosalpingostomy. INTERVENTION(S): Samples were cryopreserved, then thawed and centrifuged to remove cellular debris. MAIN OUTCOME MEASURE(S): The supernatants were analyzed for the presence of human interferon-gamma, epidermal growth factor, transforming growth factor-beta2, and tumor necrosis factor-alpha by quantitative enzyme immunoassay kits. RESULT(S): Interferon-gamma and transforming growth factor-beta2 were not detected in any of the hydrosalpingeal fluid samples. Epidermal growth factor was present in 5 of 10 hydrosalpingeal fluid samples, with a mean (+/- SE) concentration of 26.7+/-11.4 pg/mL. Tumor necrosis factor-alpha was detected in 7 of 10 samples, with a mean (+/- SE) concentration of 6.2+/-3.6 pg/mL. Three of the 10 samples contained both tumor necrosis factor-alpha and epidermal growth factor. CONCLUSION(S): For the first time, we described the absence of interferon-gamma and transforming growth factor-beta2, and the presence of epidermal growth factor and tumor necrosis factor-alpha in human hydrosalpingeal fluid. Because the fundamental role of the human fallopian tube is secretory in nature, the alteration in substances secreted from the tubal epithelium that reflux into the uterine cavity may explain the deleterious effects that hydrosalpingeal fluid has on pregnancy rates after IVF-ET.
Body Fluids↗
Action of ethanol on responses to nicotine from cerebellar Purkinje neurons: relationship to methyllycaconitine (MLA) inhibition of nicotine responses.
The effect of ethanol on responses to nicotine from rat cerebellar Purkinje neurons was investigated using extracellular single-unit recording. Systemic administration of ethanol initially enhanced the nicotine-induced inhibition from 50% of the Purkinje neurons. However, irrespective of whether there was an initial enhancement, systemic administration of ethanol antagonized the response to nicotine from the majority of Purkinje neurons. When varying ethanol concentrations were electro-osmotically applied to this neuronal cell type, the responses to nicotine (6/8) were enhanced when a low concentration of ethanol (40 mM) was in the pipette, whereas the majority of nicotine responses (10/11) were antagonized when a higher concentration of ethanol (160 mM) was applied to Purkinje neurons. Thus, the concentration of ethanol presented to the neuron seemed to explain the biphasic consequence of systemically administered ethanol on responses to nicotine. In order to determine whether ethanol affected a specific nACh receptor subtype containing the alpha-7 subunit, it was initially established that the nicotinic antagonists, alpha-bungarotoxin (alpha-BTX) and methyllycaconitine (MLA), which are associated with this subunit, had identical actions on responses to nicotine from Purkinje neurons. When MLA was tested against responses to nicotine from this cell type, MLA antagonized the response to nicotine from 45% (9/20) of the neurons tested. In a direct comparison of the action of ethanol to inhibit responses to nicotine with the action of MLA on the same Purkinje neuron, ethanol inhibited responses to nicotine on all neurons sensitive to MLA. However, ethanol also affected nicotine-induced neural changes from some Purkinje neurons not sensitive to MLA antagonism of nicotine. These data support the supposition that ethanol affects a nACh receptor subtype which has an alpha-7 subunit as well as other nACh receptor subtypes without this specific subunit.
Aconitine↗
DNA binding studies of a solvatochromic fluorescence probe 3-methoxybenzanthrone.
A fluorescence probe of 3-methoxybenzanthrone (MBA) exhibits significant solvatochromic characteristics correlated with the polarity of solvents. The interaction of the solvatochromic fluorescence probe with calf thymus DNA (ct-DNA) has been investigated. In the presence of ct-DNA the fluorescence of MBA is strongly quenched with a blue-shift of emission peak and a hypochromism in absorption spectra. The absorption spectra, fluorescence quenching and fluorescence polarization experiments show that the MBA molecule as an intercalator is inserted into the base-stacking domain of the ct-DNA double helix, and the interaction of the nucleobases with the MBA molecule causes quenching of fluorescence and hypochromism in the absorption spectra. The intrinsic binding constant and the binding site number were determined to be 1.70 x 10(5) mol l-1 in base pairs and six, respectively. The I0/I versus [ct-DNA] plot shows linear relationship in the range covering 4.3 x 10(-7)-1.02 x 10(-4) mol l-1 in base pairs which can be used for ct-DNA determination. The limit of detection was found to be 4.3 x 10(-7) mol l-1 in base pairs (0.5 microgram ml-1).
Absorption↗
Pungent principal of Alpinia galangal (L.) swartz and its applications.
The pungent principal of galangal [Alpinia galangal (L.) Swartz] rhizomes was isolated and identified as 1'-acetoxychavicol acetate (galangal acetate). Galangal acetate exhibits a unique pungent sensation, which is less intense than that of capsaicin and without a lingering effect. Applications of galangal acetate were tested in beverages, sweet goods, dressings, and personal care products. In many applications, galangal acetate is preferred to other pungent ingredients. It can be used as an alcohol enhancer or an alcohol replacer in alcohol and alcohol-free beverages. Galangal acetate is not stable in aqueous solutions and undergoes hydrolysis/isomerization reactions. Therefore, galangal acetate was absent in galangal essential oil obtained by steam distillation. However, galangal acetate was found as one of the major volatile components of the galangal rhizomes by headspace GC analysis. The stability of galangal acetate was studied under various conditions.
Benzyl Alcohols↗
BRCA1 and BRCA2 in breast cancer.
Breast cancer, one of the most common serious malignancies affecting women, occurs in hereditary and sporadic forms. Hereditary breast cancer accounts for 5-10% of all cases and has some distinctive clinical features compared with sporadic breast cancer. The recently identified genes BRCA1 and BRCA2 appear to account for the majority of hereditary breast cancer in US and European populations. Both of these genes have already been localized and isolated; however, the exact functions of their proteins are not clear yet. The detection of LOH in the 17q21 and 13q12-q13 regions, where the BRCA1 and BRCA2 genes are located, indicates that BRCA1 and BRCA2 act as tumor suppressor genes. The list of identified germline mutations in BRCA1 and BRCA2 is still growing, and mutation carriers have a substantial lifetime risk of both breast and ovarian cancer. However, it is still undetermined whether BRCA1 and BRCA2 play similar important roles in sporadic breast cancer. This paper reviews the current advances in BRCA1/BRCA2 research: the structure of their genes and proteins, their mutation frequencies, their possible roles in both hereditary and sporadic breast cancers, and their functions in transcriptional regulation and DNA repair.
BRCA1 Protein↗
Rhizomelic chondrodysplasia punctata, a peroxisomal biogenesis disorder caused by defects in Pex7p, a peroxisomal protein import receptor: a minireview.
Rhizomelic chondrodysplasia punctata (RCDP) is a lethal autosomal recessive disease corresponding to complementation group 11 (CG11), the second most common of the thirteen CGs of peroxisomal biogenesis disorders (PBDs). RCDP is characterized by proximal limb shortening, severely disturbed endochondrial bone formation, and mental retardation, but there is an absence of the neuronal migration defect found in the other PBDs. Plasmalogen biosynthesis and phytanic acid oxidation are deficient, but very long chain fatty acid (VLCFA) oxidation is normal. At the cellular level, RCDP is unique in that the biogenesis of most peroxisomal proteins is normal, but a specific subset of at least four, and maybe more, peroxisomal matrix proteins fail to be imported from the cytosol. In this review, we discuss recent advances in understanding RCDP, most prominently the cloning of the affected gene, PEX7, and identification of PEX7 mutations in RCDP patients. Human PEX7 was identified by virtue of its sequence similarity to its Saccharomyces cerevisiae ortholog, which had previously been shown to encode Pex7p, an import receptor for type 2 peroxisomal targeting sequences (PTS2). Normal human PEX7 expression rescues the cellular defects in cultured RCDP cells, and cDNA sequence analysis has identified a variety of PEX7 mutations in RCDP patients, including a deletion of 100 nucleotides, probably due to a splice site mutation, and a prevalent nonsense mutation which results in loss of the carboxyterminal 32 amino acids. Identification of RCDP as a PTS2 import disorder explains the observation that several, but not all, peroxisomal matrix proteins are mistargeted in this disease; three of the four proteins deficient in RCDP have now been shown to be PTS2-targeted.
Animals↗
Mice lacking Smad3 show accelerated wound healing and an impaired local inflammatory response.
The generation of animals lacking SMAD proteins, which transduce signals from transforming growth factor-beta (TGF-beta), has made it possible to explore the contribution of the SMAD proteins to TGF-beta activity in vivo. Here we report that, in contrast to predictions made on the basis of the ability of exogenous TGF-beta to improve wound healing, Smad3-null (Smad3ex8/ex8) mice paradoxically show accelerated cutaneous wound healing compared with wild-type mice, characterized by an increased rate of re-epithelialization and significantly reduced local infiltration of monocytes. Smad3ex8/ex8 keratinocytes show altered patterns of growth and migration, and Smad3ex8/ex8 monocytes exhibit a selectively blunted chemotactic response to TGF-beta. These data are, to our knowledge, the first to implicate Smad3 in specific pathways of tissue repair and in the modulation of keratinocyte and monocyte function in vivo.
Animals↗
Characterization of immune responses following intramuscular DNA immunization with the MOMP gene of Chlamydia trachomatis mouse pneumonitis strain.
Studies were carried out to characterize the cellular and humoral immune responses evoked by intramuscular DNA vaccination with the major outer membrane protein (MOMP) gene of Chlamydia trachomatis mouse pneumonitis strain. The data demonstrate that DNA vaccinated mice develop antigen-specific delayed-type hypersensitivity, lymphocyte proliferation and interferon-gamma (IFN-gamma) production. Serum antibody responses (mainly immunoglobulin G2a; IgG2a) were evoked in two-thirds of the mice. We conclude that intramuscular DNA immunization with the MOMP gene evokes cellular and humoral immune responses suggestive of a T helper 1 (Th1) bias.
Animals↗
Systemic mycobacterial infection inhibits antigen-specific immunoglobulin E production, bronchial mucus production and eosinophilic inflammation induced by allergen.
As the burden of infectious diseases becomes reduced in many countries, a remarkable increase in the incidence of allergies has occurred. The basis for the rise in atopic disorders as a correlate of the decline in infectious diseases has not been defined. In the present study, we tested experimentally whether prior systemic infection with Mycobacterium bovis bacillus Calmette Guérin (BCG) had any effect on ovalbumin (OVA) Al(OH)3 (alum)-induced immunoglobulin E (IgE) production, airway mucus production and eosinophilic inflammation. The data showed that allergen-specific IgE production and OVA-induced eosinophilia and goblet cell development were significantly inhibited by prior infection with BCG. Correspondingly, following immunization with OVA alum, BCG-infected mice exhibited significantly higher levels of allergen-driven interferon-gamma (IFN-gamma) production than the mice without infection. The ratio of IFN-gamma: interleukin (IL)-4 production was higher in OVA-sensitized mice with prior BCG infection than in those without infection. The abrogation of OVA-induced mucus production and pulmonary eosinophilia in BCG-infected mice correlated with significantly decreased IL-5 production and increased IFN-gamma and IL-12 production. These data provide direct evidence that intracellular bacterial infection (i.e. BCG) can inhibit antigen-specific IgE and airway reactivity induced by environmental allergen. Furthermore, the results suggest that changes in cytokine-producing patterns of T lymphocytes and other cells may be the mechanism by which infections influence allergies.
Allergens↗
Age-dependent development and surface ultrastructural changes following electrical activation of bovine oocytes.
Electrical activation of oocytes is a key component of the current mammalian cloning regimen. The present study examined the surface ultrastructure alterations of bovine oocytes at different ages following electrical pulse (EP) activation. In Experiment 1, bovine oocytes 22, 30 and 40 h after in vitro maturation were activated by EP. Significantly higher pronuclear formation (57 or 59%) was obtained for the 30- or 40-h oocytes than for the 22-h oocytes (10%). More oocytes (58%) in the 40-h group activated spontaneously than in the 22- or 30-h groups. In Experiment 2, oocytes were cultured for 1, 2, 4 and 8 h after activation and then evaluated by scanning electron microscopy (SEM). The zona pelucida (ZP) meshwork was completely abolished within 1 h after EP in the majority of the oocytes in the 22- and 30-h groups, but no obvious changes were observed in the 40-h group. From 2 h onward, the ZP meshwork was gradually restored in most treated oocytes. It was also noted that the microvilli pattern on the vitelline surface was altered dramatically after EP treatment, with the proportion affected increasing with oocyte age. The present study extends the previous findings that older oocytes are more readily activated and that the age-dependent surface ultrastructural alterations correlate very well with the age dependent activation of oocytes.
Aging↗
Assessment of novel anti-p185HER-2 monoclonal antibodies for internalization-dependent therapies.
Novel therapies that require internalization of effector domains may be improved by assessing the efficacy of postbinding receptor-mediated endocytosis. To achieve targeted gene therapy of immunotoxin therapy, natural vector-host tropisms must be altered. Recent improvements in monoclonal antibody (MAb) engineering have expanded the potential range of host cells that can be targeted for therapeutic intervention. However, relatively little is known about cellular responses after binding of a vector construct. We have tested the utility of four novel MAbs recognizing the extracellular domain of p185HER-2, a membrane receptor protein, for use in internalization-dependent therapies. All four antibodies bound to p185HER-2 in a number of immunoassays. Two antibodies recognized accessible epitopes of p185HER-2 on viable cells. Radioimmunoassay demonstrated that antibody-membrane receptor complexes formed by two antibodies were internalized and trafficked through an endolysosomal degradative pathway. Two of the four antibodies evaluated were found to have favorable internalization characteristics suitable for incorporation in a targeting vector. This analytical approach could be applied to antibodies prior to and after fusion with various vectors or toxins to determine the potential utility of the antibodies for targeted therapy.
Animals↗
Interplay of maturation-promoting factor and mitogen-activated protein kinase inactivation during metaphase-to-interphase transition of activated bovine oocytes.
The objective of the present study was to examine the activity changes in histone H1 kinase (also known as maturation-promoting factor [MPF]) and mitogen-activated protein kinase (MAPK) and their constituent proteins in in vitro-matured bovine oocytes after in vitro fertilization (IVF) or after parthenogenetic activation induced by calcium ionophore A23187 alone or by the ionophore followed by either 6-dimethylaminopurine (6-DMAP) or cycloheximide (CHX). Inactivation of both H1 kinase and MAPK occurred after both A23187+6-DMAP treatment and IVF; inactivation of H1 kinase preceded inactivation of MAPK. However, MAPK was inactivated much earlier in 6-DMAP-treated oocytes. Further analysis of constituent cell cycle proteins of these kinases by Western blot showed that A23187 alone could not induce changes in cdc2, cdc25, or ERK2 but induced reduction of cyclin B1. IVF and A23187+CHX induced similar changes: cyclin B1 was destroyed shortly after activation followed by accumulation of cyclin B1, phosphorylation of cdc2, and dephosphorylation of ERK2 at pronuclear formation 15 h after activation. No change in cdc25 was observed at this time. In contrast, A23187+6-DMAP treatment resulted in earlier phosphorylation of cdc2 and dephosphorylation of ERK2 at 4 h after treatment when the pronucleus formed. Moreover, accumulation of both cdc25 and cyclin B1 was detected at 15 h. Microinjection of ERK2 antibody into A23187-treated oocytes resulted in pronuclear formation. In conclusion, activation of bovine oocytes with 6-DMAP led to earlier inactivation of MAPK, while CHX induced inactivation of MAPK parallel to that following sperm-induced oocyte activation. Destruction of cyclin B is responsible for inactivation of MPF, while phosphorylation of cdc2 is likely responsible for maintaining its low activity. Inactivation of MAPK is closely associated with pronuclear development regardless of the activation protocol used.
Adenine↗
Development of cellular polarity of hamster embryos during compaction.
Development of cellular polarity is an important event during early mammalian embryo development and differentiation. Blastomeres of hamster embryos at various stages were examined by scanning electron microscopy (SEM) and immunocytochemical staining. SEM observations revealed that 1- to 7-cell-stage embryos showed a uniform distribution of microvilli throughout the cell surface. Microvillous polarization was initially noted in the blastomeres (10-35%) of 8-cell-stage embryos. The polarized microvilli were observed mostly in the basal region of cell-cell contact and occasionally at the apical, outward-facing surface of the blastomere. Fluorescein-isothiocyanate-conjugated concanavalin A failed to reveal any polarity in the blastomeres regardless of the stages of the embryos. Actin staining showed that microfilaments were present beneath the cell surface, and in addition, areas of cell contact were more heavily stained, indicating a thick microfilament domain. Microtubules were located throughout the cytoplasm and were heavily concentrated near the nucleus during interphase, although they became redistributed in the region of the mitotic spindle during karyokinesis. The position of nucleus changed from the cell center to the apical, outward-facing surface of the cell, and it distanced itself from the basal microvillous pole. It is suggested that the changes in the cell surface and nuclear position are the first manifestations of cell polarity in peri-compacted hamster embryos, which appear as early as the 8-cell stage; furthermore, the outward migration of the nuclei may parallel the redistribution of microtubules in the cytoplasm.
Animals↗
The continuous assessment of cerebrovascular reactivity: a validation of the method in healthy volunteers.
UNLABELLED: Using transcranial Doppler ultrasonography, we investigated the moving correlation between slow waves in arterial blood pressure (ABP) and blood flow velocity (FV) at different levels of cerebrovascular vasodilation provoked by changing PETCO2. Fourteen healthy volunteers were examined. The FV in middle cerebral arteries, PETCO2, and ABP were recorded during normocapnia, hypercapnia, and hypocapnia. The moving correlation coefficients between ABP and mean FV (FVm) or systolic FV (FVs) during spontaneous fluctuations in ABP were calculated for 3-min epochs and averaged for each investigation, thus yielding the mean index (Mx) and systolic index (Sx). As a reference method, Aaslid's cuff tests were performed to obtain the rate of regulation (RoR). RoR, Mx, and Sx significantly depended on PETCO2 (analysis of variance, P < 0.00001). At high PETCO2, cerebrovascular reactivity was disturbed as reflected in RoR values of < 0.17/s for all volunteers and increased values of Mx (> 0.4 in 86% of volunteers) and Sx (> 0.2 in 79% of volunteers). Overall, there was a reasonably good correlation of both Mx and Sx with RoR (R2 = 0.65 and 0.58, respectively). IMPLICATIONS: Indices derived from the correlation between spontaneous fluctuations of blood flow velocity wave form and arterial blood pressure may be used for the noninvasive continuous monitoring of cerebrovascular reactivity.
Adult↗
In pursuit of a human chlamydial vaccine.
The best way to control chlamydial diseases is with an effective vaccine. Although previous studies suggest that a vaccine is an achievable goal, progress has been limited even though many vaccination strategies have been tested. A clearer understanding of the immunobiological basis of chlamydial protection and pathology will be critical for future research in chlamydial vaccination.
Journal Article↗
Gap junctions regulate responses of tendon cells ex vivo to mechanical loading.
Avian digital flexor tendons were used with a device to apply load ex vivo to study the effects on deoxyribonucleic acid and collagen synthesis when cell to cell communication is blocked. Flexor digitorum profundus tendons from the middle toe of 52-day-old White Leghorn chickens were excised and used as nonloaded controls, or clamped in the jaws of a displacement controlled tissue loading device and mechanically loaded for 3 days at a nominal 0.65% elongation at 1 Hz for 8 hours per day with 16 hours rest. Tendon samples were radiolabeled during the last 16 hours with 3H-thymidine to monitor deoxyribonucleic acid synthesis or with 3H-proline to radiolabel newly synthesized collagen. Cyclic loading of whole avian flexor tendons stimulated deoxyribonucleic acid and collagen synthesis, which could be blocked with octanol, a reversible gap junction blocker. Cells from human digital flexor tendon were used to populate a rectangular, three-dimensional, porous, polyester foam that could be deformed cyclically in vitro. Together, these results support the hypothesis that tendon cells must communicate to sustain growth and matrix expression and that an engineered three-dimensional construct can be used to study responses to mechanical load in vitro.
Animals↗
Biochemical characterization of the suberization-associated anionic peroxidase of potato.
The anionic peroxidase associated with the suberization response in potato (Solanum tuberosum L.) tubers during wound healing has been purified and partially characterized at the biochemical level. It is a 45-kD, class III (plant secretory) peroxidase that is localized to suberizing tissues and shows a preference for feruloyl (o-methoxyphenol)-substituted substrates (order of substrate preference: feruloyl > caffeoyl > p-coumaryl approximately syringyl) such as those that accumulate in tubers during wound healing. There was little influence on oxidation by side chain derivatization, although hydroxycinnamates were preferred over the corresponding hydroxycinnamyl alcohols. The substrate specificity pattern is consistent with the natural substrate incorporation into potato wound suberin. In contrast, the cationic peroxidase(s) induced in response to wound healing in potato tubers is present in both suberizing and nonsuberizing tissues and does not discriminate between hydroxycinnamates and hydroxycinnamyl alcohols. A synthetic polymer prepared using E-[8-(13)C]ferulic acid, H(2)O(2), and the purified anionic enzyme contained a significant amount of cross-linking through C-8, albeit with retention of unsaturation.
Cations↗