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At least 181 records · Page 10Linked to original sources

PubMed2002

Mass spectrometric determination of ergosterol in a prairie natural wetland.

Fungi are the main decomposers of plant material in an aquatic system. Levels of ergosterol, a compound generally specific to the cell membranes of fungi can be used as an indirect measure of their presence and biomass. Described is a procedure utilising reversed-phase liquid chromatography with positive-ion atmospheric pressure chemical ionization tandem mass spectrometry (LC-APCI-MS-MS) for full quantification and confirmation of ergosterol in various wetland matrices. Solid and liquid samples (0.2-1 g dry weight and 10 ml) were subjected to alkaline saponification followed by serial extraction using pentane (3 x 10 ml). The procedure was applicable to quantitative analysis of wetland samples with little or no clean up. Under low energy (CID) collision induced dissociation conditions the major product-ion formed from m/z 379.4 [M + H-H2O]+ was m/z 69.4 [(CH3)2CHCH=CH]+. Selected reaction monitoring (SRM) of this transition along with the retention time were used to confirm that ergosterol was widely distributed at ppm levels (2.4 to 303 microg ash free dry mass (AFDM)) in matrices of decaying willow leaves, Scirpus stems (living and dead) and sediment collected at the water-sediment interface. Comparison between LC-APCI-MS-MS (SRM), LC-APCI-MS using selected ion monitoring (SIM) and liquid chromatography with ultraviolet absorption detection (LC-UV) indicated that SRM analysis was the most selective technique.

Chromatography, Liquid↗

PubMed1998

Processed acrylic resin provisional restoration with lingual cast metal framework.

Fixed provisional prostheses are fabricated to maintain, improve, and/or change oral function and esthetics for varying periods. It is important to know when to provide a provisional prostheses and how to make one so that it will meet the needs of the patient. This article describes a modification of the design of a cast metal reinforced processed acrylic resin provisional restoration for extensive, long-term reconstruction with implants, because some of the treatments rendered to patients require temporization for up to 2 years. This design has been used by the authors since 1991, and has resulted in fewer problems of fracture of the provisional restorations. In addition, removable partial dentures are rarely needed, even when large spans exist between remaining abutments in serial extractions. This procedure also permits performing guided bone regeneration for deficient ridges without the problem of transmucosal loading, while still maintaining the patient's esthetics and function after surgery.

Acrylic Resins↗

PubMed2003

Neurological basis of language and sequential cognition: evidence from simulation, aphasia, and ERP studies.

The current research addresses the hypothesis that certain aspects of sequential cognition have made substantial contributions to the human language processing capability, from a functional neurophysiology perspective. We first describe a cognitive sequence processing model that was developed based on the functional neuroanatomy of primate cortex and basal ganglia. We demonstrate how this model is capable of simulating the behavior of human infants in extracting serial, temporal and abstract structure from language-like sound sequences as revealed in recent psycholinguistic experiments. We then demonstrate how, through training, this model can perform adult level syntactic comprehension, based on dissociated processing streams for open vs. closed class words. The model subsequently predicts: (1) that impaired syntactic processing (as in agrammatic aphasia) will be associated with impairments in corresponding non-linguistic cognitive sequencing tasks, and (2) that neurophysiological processes (as revealed by ERPs) involved in syntactic processing should also be involved in the corresponding non-linguistic cognitive sequencing tasks. Data confirming these predictions are reviewed. We conclude that the study of sequential cognition will provide a new paradigm for the investigation of the neurophysiological bases of language.

Aphasia, Broca↗

PubMed2003

Purification of N-terminally truncated histone H2A-monoubiquitin conjugates from leukemic cell nuclei: probable proteolytic products of ubiquitinated H2A.

To gain insight into the significance of nuclear ubiquitinated proteins, two serial extracts prepared from various leukemic cells were analysed by western blotting with anti-ubiquitin antibody. Two previously unidentified ubiquitinated proteins with molecular masses of 10 and 17 kDa were found in 8 M urea-soluble extracts, obtained from Tris-buffer-insoluble materials, of acute myeloid leukemia OCI/AML 1a cells and the cells from the leukemia patients. Both proteins were successfully purified from the OCI/AML 1a cells and identified as monoubiquitin-truncated H2A conjugates, the 10 kDa ubiquitinated H2A(115-129) and the 17 kDa ubiquitinated H2A(54-129), suggesting that both proteins were produced by limited proteolysis of an intact form (23 kDa) of ubiquitinated H2A(1-129). The 17 kDa protein as well as the 23 kDa ubiquitinated histone H2A were localised in chromatin fractions of the OCI/AML cells and released by high concentrations of salt in a micrococcal nuclease-sensitive manner, suggesting their association with chromatin. In contrast, the 10 kDa protein remained insoluble even when the nuclei were treated with nuclease under high salt concentrations, presumably due to binding to the nuclear matrix. An antibody recognising H2A(70-81) also detected the 17 kDa protein in anti-ubiquitin immunoprecipitates obtained from the OCI/AML cell nuclei. In addition, the 17 kDa protein levels in THP-1 cells were transiently increased, concomitant with a decrease in the 23 kDa ubiquitinated H2A, by treatment with phorbol 12-myristate 13-acetate or all-trans-retinoic acid, both of which induce differentiation. This is the first report of probable proteolytic products of ubiquitinated H2A, which might have a role in nuclear functions.

Amino Acid Sequence↗

PubMed2003

Analysis of 12 different pentacyclic triterpenic acids from frankincense in human plasma by high-performance liquid chromatography and photodiode array detection.

For the determination of pentacyclic triterpenes of the boswellic acid family in human plasma a novel sensitive method was developed combining serial extraction on diatomaceous earth and graphitized carbon black followed by reversed phase high-performance liquid chromatography (HPLC) and photodiode array detection. The overall average extraction yield of 12 different pentacyclic triterpenic acids was approximately 66%. The calibration graphs were linear with coefficients of correlation for all compounds greater than 0.999. The overall within-day and between-day coefficients of variation (CV) for the 12 pentacyclic triterpenic acids were 5.6 and 6.8%, respectively. This HPLC procedure delivers the analytical sensitivity, precision and accuracy required for clinical pharmacokinetic and therapeutic studies.

Boswellia↗

PubMedDate not supplied

Proteome analysis of tobacco bright yellow-2 (BY-2) cell culture plastids as a model for undifferentiated heterotrophic plastids.

We analyzed the proteome of undifferentiated plastids from a tobacco BY-2 cell culture by shotgun proteomics following multidimensional protein fractionation. The fractionation strategy initiated with the serial extraction of proteins from membranes which allowed us to distinguish soluble, peripheral, and integral membrane proteins. The majority of the identified proteins have a function in the cellular metabolism and most of them are active in amino acid synthesis pathways. A significant number of the identified proteins was not identified in chloroplast proteome analyses before. This suggests BY-2 plastid specific functions that differ from the major activities of chloroplasts. We have used the BY-2 plastid proteins reported here to assess the metabolic activities of undifferentiated heterotrophic plastids and compared the functional profile with that of differentiated heterotrophic amyloplasts. Comparative shotgun proteome analyses as reported here provide information about prevalent metabolic activities of different plastid types.

Cell Differentiation↗

PubMed1997

Heterogeneity in buffalo pituitary prolactin.

The Ellis procedure of serial extraction of gonadotropins and growth hormone (GH) followed by alkaline ethanol extraction was adopted to process freshly frozen buffalo pituitaries. The procedure after slight modification was found very useful as more than 2 mg of GH free immunoreactive prolactin (PRL) could be isolated from each gram of wet pituitary tissue. Further, the biochemical purity and immunobiological potency of the extracted PRL, designated as P-I, was comparable with that of the highly purified samples of homologous and heterologous PRLs. No non-PRL protein was detectable in P-I. Micro-heterogeneity with regard to size, charge, co- and post-translational modifications was also investigated under different conditions of extraction and at different stages of purification. Immunological and biological potencies were compared in homologous competitive enzyme linked immunosorbent assay (ELISA) developed for buffalo PRL and in rat Nb2 lymphoma proliferation assay respectively. Structural heterogeneity was observed in all the preparations checked including fresh pituitary homogenate and highly purified hormone. Nevertheless a 25 K species corresponding to the hormone monomer was always the only paramount form comprising more than 90% of the total PRL protein in all the samples including P-I. Similar size forms were observed in all preparations and were found to be equivalents of monomers, dimers, covalent-and non-covalent multimers, disulphide bridged forms and cleaved fragments. Other sibling species identified were glycosylated PRL, charge isoforms and forms that perhaps differed in their extractability from the pituitary tissue. Strong apparent size heterogeneity was displayed by the monomeric buffalo PRL. In light of these observations and the information on the structural and functional significance and the consequences of polymeric forms, the use of a heterogeneous PRL (P-I) as a reference hormone is recommended for a valid assay.

Animals↗

PubMed1999

T-lymphocyte cytokine profiles in compositae airborne dermatitis.

Compositae airborne dermatitis is a well-recognized disorder characterized by erythematosquamous lesions and papules on light-exposed areas. The presence of positive patch test reactions and the absence of specific serum IgE suggest delayed-type hypersensitivity, the murine model of which is characterized by a Th1 cytokine production profile [high amounts of interferon (IFN)-gamma and interleukin (IL)-2; little or no IL-4 and IL-5]. The aim of this study was to evaluate the cytokine profile of T-cell lines and T-cell clones from peripheral blood in a 38-year-old non-atopic male woodcutter affected by seasonal airborne contact dermatitis. The patient showed positive patch test reactions to several Compositae extracts (Achillea millefolium, Chamomilla recutita, Tanacetum parthenium, T. vulgare) and sesquiterpene lactone mix. On prick testing with Compositae and other plants, serum-specific IgE levels and phototesting were negative or normal. Allergen-specific T-cell lines produced with Compositae extracts showed a good in vitro cell proliferation only to C. recutita extract. Serial cloning performed using the C. recutita-specific T-cell lines revealed an alphabeta+CD4+ phenotype with high amounts of IFN-gamma and IL-4 in T-cell clones. Thus, these cells expressed a preferential Th0 phenotype. These data suggest that in addition to IFN-gamma, other T-cell derived cytokines, such as IL-4, may play a part in the immunopathogenesis of contact dermatitis.

Adult↗

PubMed2002

Implant-supported, long-span fixed partial denture for a scleroderma patient: a clinical report.

Scleroderma poses many difficulties and challenges for the treating dentist. Until now, dental implant treatment for patients with scleroderma was limited to either complete overdentures or short-span fixed partial dentures. This clinical report describes the use of modified techniques to fabricate a long-span fixed prosthesis delivered after serial extractions and implant placement.

Dental Care for Chronically Ill↗

PubMed1986

Differentiation-dependent changes in the solubility of a 195-kD protein in human epidermal keratinocytes.

We have prepared a monoclonal antibody, AE11, that recognizes specifically a 195-kD protein (pI 5.4) of human keratinocytes. This antigen constitutes approximately 0.01-0.1% of total protein in keratinocytes of skin, esophagus, and cornea, and is readily detectable in these cells by immunofluorescent staining and immunoblotting. However, it is barely detectable in MCF mammary carcinoma cells and HeLa cells, and is undetectable in nonepithelial cell types. Results from serial extraction experiments have shown that this protein exists in two distinct pools: a Tris-soluble, and a Tris-insoluble but urea- or SDS-soluble one. The distribution of the 195-kD protein between these two pools appears to be differentiation-related, since relatively undifferentiated cells selected by a low-calcium medium contain primarily the soluble form, while highly differentiated cells contain mainly the insoluble form. Data from immunofluorescent staining and trypsin-sensitivity experiments suggest that the soluble form is cytoplasmic, whereas the insoluble form is submembranously located at the cell periphery of upper, differentiated cells. The insoluble, cell peripheral form of the 195-kD antigen increases progressively during epidermal differentiation; its insolubility appears to be related to the formation of disulfide-bond(s). These results indicate that the 195-kD protein, which has recently been suggested to be involved in cornified envelope formation (Simon, M., and H. Green, 1985, Cell, 36:827-834), undergoes significant changes in its solubility characteristics and intracellular location during keratinocyte maturation.

Antibodies, Monoclonal↗

PubMed1976

Synthesis of elastin. A rapid formation of lysine-derived crosslinks by chick embryo aorta.

Aortas of 13-day-old chick embryo were labeled for 0.5 hr with [14C]lysine and subjected to a serial extraction after chase for 1-24 hr with [12C]lysine. Substantial radioactivity was found in insoluble elastin after 3 hr chase. The effect of beta-amino-propionitrile on labeling with [14C]lysine was also examined. Each fraction was hydrolyzed and applied to a short column on an amino acid analyzer. Radioactivity was found in desmosine and isodesmosine of insoluble elastin as early as 1 hr after the beginning of chase. The radioactivity increased rapidly at 2 hr and very slowly thereafter. A large count, which was separated into five peaks on a long column, was observed in other lysine derivatives at 2 hr and increased steadily up to 24 hr, while the lysine count decreased from 1 : 0.5 to 1 : 6 against lysine derivatives and from 1 : 0.04 to 1 : 0.9 against quarter-desmosine after 24 hr. The oxidation of lysine residues incorporated during the 0.5 hr pulse was almost completed during the first 1 hr of chase, and these oxidized residues were incorporated into crosslinks during the following 1 hr. It is suggested that poorly crosslinked elastin accumulated in the soluble fractions. The presence of crosslinking derived from lysine residues was also indicated in the microfibril fraction.

Amino Acids↗

PubMed2004

Antibody-mediated rejection after adult ABO-incompatible liver transplantation remedied by gamma-globulin bolus infusion combined with plasmapheresis.

Adult ABO-incompatible liver transplantation has been known to be associated with markedly desperate outcomes. Antibody-mediated rejection (AMR) has been recognized as one of the primary causes of these desperate outcomes, but its clinical features and significance have not been well understood. Recently, some clinicians have succeeded in improving the outcome of adult ABO-incompatible liver transplantation. However, in some transplant patients undergoing these treatments, AMR has still led to graft losses. We recently encountered two patients suffering from AMR after adult ABO-incompatible liver transplantation and remedied their conditions with various therapeutic modalities including direct hepatic infusion therapy and gamma-globulin bolus infusion therapy combined with plasmapheresis. In this article, we describe the clinical features of these patients and the therapeutic strategies we applied. Furthermore, we show the histologic course of the recovery from AMR in the second patient, from whom we were able to extract serial liver biopsies.

ABO Blood-Group System↗

PubMed2006

Leaching of phage from Class B biosolids and potential transport through soil.

The objective of this study was to investigate leaching and transport of viruses, specifically those of an indigenous coliphage host specific to Escherichia coli ATTC 15597 (i.e., MS-2), from a biosolid-soil matrix. Serial extractions of 2% and 7% (solids) class B biosolid matrices were performed to determine the number of phage present in the biosolids and to evaluate their general leaching potential. Significant concentrations of coliphage were removed from the biosolids for each sequential extraction, indicating that many phage remained associated with the solid phase. The fact that phage was associated with or attached to solid particles appeared to influence the potential for release and subsequent transport of phage under saturated-flow conditions, which was examined in a series of column experiments. The results indicated that less than 8% of the indigenous coliphage initially present in the biosolids leached out of the biosolid-soil matrix. A fraction of this was subsequently transported through the sandy porous medium with minimal retention. The minimal retention observed for the indigenous phage, once released from the biosolids, was consistent with the results of control experiments conducted to examine MS-2 transport through the porous medium.

Coliphages↗

PubMed1986

Description and characterization of a surface lectin from Giardia lamblia.

The mechanisms by which the human enteric pathogen Giardia lamblia colonizes the proximal small intestine are poorly understood. Although the parasite possesses an attachment organelle on its ventral surface, the "sucking" disk, we considered that like many bacteria and some protozoa, G. lamblia might also have a surface membrane-associated modality for adherence to its host. Using an erythrocyte mixed-agglutination model, we demonstrated a parasite surface lectin with specificities for D-glucosyl and D-mannosyl residues. This lectin is soluble in Triton X-100, is calcium dependent, and is maximally active at pH 5.5 to 6.0. Partial purification was achieved by serial extraction of parasites in Triton X-100 followed by Sephadex G-150 affinity chromatography. The lectin could not be surface radiolabeled with 125I-Bolton-Hunter reagent, but radiolabeling of the hapten eluate from an affinity column produced four bands of 57,000 to 78,000 Mr on sodium dodecyl sulfate-polyacrylamide gels under reducing conditions. The biological function of this lectin is unknown. The presence of mannosyl residues on the luminal surface of human small intestinal epithelial cells suggests that there are receptors for Giardia lectin at the site of colonization.

Animals↗

PubMed1986

Identification and characterization of a major early cytomegalovirus DNA-binding protein.

We characterized a DNA-binding protein with an approximate molecular weight of 129,000 (DB129) which is present in the nuclei of cytomegalovirus- (strain Colburn) infected cells, but not in virus particles. Results of two types of experiments demonstrated that DB129 is a member of the early class of herpesviral proteins. First, time course pulse-labeling experiments showed that its synthesis begins after that of the immediate-early protein IE94, but prior to the appearance of late viral proteins, and was reduced at late times. Second, in the presence of inhibitors of viral DNA replication, DB129 continued to be made and accumulated to elevated levels. A second set of experiments showed that DB129 bound to single-stranded DNA in vitro and was eluted by a NaCl gradient in two peaks, one at about 0.2 M and the second at about 0.6 M. A similar pattern of release was observed when infected-cell nuclei were serially extracted with increasing NaCl concentrations. In addition, treatment of nuclei with DNase I selectively released DB129, along with a small but significant fraction of another DNA-binding protein, DB51. These results suggest that DB129 is associated with DNA in vivo and that it interacts directly with single-stranded DNA. It was also shown that cells infected with human cytomegalovirus (strain Towne) contain a slightly larger counterpart to DB129, which was designated DB140. Similarities between these proteins and the major DNA-binding protein of herpes simplex virus are discussed.

Cell Nucleus↗

PubMed1980

Keratinization of human keratinocytes in cell culture: the effect of cyclic AMP.

Human keratinocytes in culture were treated with dibutyryl cyclic AMP (DBcAMP) at concentrations of 10(-3) and 10(-4) M, and labeled with [3H]histidine for 48 hours. The proteins of the keratinocytes were serially extracted in 0.25 M sucrose, 0.1 M sodium citrate-citric acid (pH 2.6), 6 M urea-0.1 M Tris-HCl(pH 9.0), and 6 M urea-0.1 M Tris-HCl(pH 9.0) with 1% mercaptoethanol. The incorporation of [3H]histidine into the extract as assayed by DPM of 3H/microgram protein was increased in 0.25 M sucrose extract and Tris-urea extract of the cultures treated with 10(-3) M and 10(-4) M DBcAMP as compared with the control culture. There was no difference between the citrate-buffer extract of the control and that of the DBcAMP-treated cultures. The incorporation of [3H]histidine into the Tris-urea-mercaptoethanol extract was small, and this fraction was thought to be inactive metabolically. It was concluded that dibutyryl cycli AMP stimulated the protein synthesis of the cultured keratinocytes and induced a qualitative change toward accelerating the synthesis of keratinous protein.

Bucladesine↗

PubMed2000

Anti-estrogenic activity of diesel exhaust particles.

Estrogenic and anti-estrogenic activities of diesel exhaust particles (DEP) were evaluated using yeast cells expressing the human estrogen receptor and the responsive element regulating the expression of the receptor gene for beta-galactosidase (Routledge and Sumpter, 1996). It was found that a suspension of whole DEP suspension is not estrogenic but that this preparation possesses the ability to reduce the estrogen-dependent reporter activity. DEP were serially extracted with hexane, benzene, dichloromethane, methanol, and 1 M ammonia, and the estrogenic and anti-estrogenic activities of these preparations were determined. None of the extracts of DEP were estrogenic, but the extracts of benzene, dichloromethane and methanol possessed anti-estrogenic activity, and the activity of estrogen in the presence of hexane extract was slightly decreased. These results indicated that DEP contain heterologous compounds having anti-estrogenic activity. It is thought that those compounds in DEP can modulate the activity of estrogen, leading to the distruption of balance between estrogen and androgen. In this paper, the environmental effects of DEP in relation to the endocrine disrupting effect of organic compounds in DEP are discussed.

Air Pollutants↗

PubMed2003

Diagnosis of Smith-Lemli-Opitz syndrome by ultraviolet spectrophotometry.

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive disorder due to an inborn error of cholesterol metabolism, characterized by congenital malformations, dysmorphism of multiple organs, mental retardation and delayed neuropsychomotor development resulting from cholesterol biosynthesis deficiency. A defect in 3 -hydroxysteroid-delta7-reductase (delta7-sterol-reductase), responsible for the conversion of 7-dehydrocholesterol (7-DHC) to cholesterol, causes an increase in 7-DHC and frequently reduces plasma cholesterol levels. The clinical diagnosis of SLOS cannot always be conclusive because of the remarkable variability of clinical expression of the disorder. Thus, confirmation by the measurement of plasma 7-DHC levels is needed. In the present study, we used a simple, fast, and selective method based on ultraviolet spectrophotometry to measure 7-DHC in order to diagnose SLOS. 7-DHC was extracted serially from 200 l plasma with ethanol and n-hexane and the absorbance at 234 and 282 nm was determined. The method was applied to negative control plasma samples from 23 normal individuals and from 6 cases of suspected SLOS. The method was adequate and reliable and 2 SLOS cases were diagnosed.

Biomarkers↗