Factors that exacerbate linear IgA disease.
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Adult↗
Biomedical subjects
J B Smith
Publications and source records attributed to J B Smith.
Multiple collagenomas in a patient with Down syndrome.
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Child↗
Herpes zoster and internal malignancy.
Herpes zoster (HZ) often occurs concomitantly with various internal malignancies, most commonly hematologic in origin. Authors in the past proposed that HZ was a marker for internal malignancy, since it is often found in association with a malignancy. A critical review of the literature revealed that when HZ and malignancy occur in the same individual, rarely does HZ precede the malignancy, but usually follows it. Many studies have evaluated HZ in cancer patients, but only three studies have evaluated the occurrence of malignancy after the diagnosis of HZ, and all found no increased incidence of internal malignancy in patients with HZ. Since HZ is a poor marker for internal malignancy, extensive workups to find occult malignancy are not indicated. In rare cases, however, HZ precedes a malignancy. We therefore recommend a baseline history and physical examination, with further directed workup only if there are abnormal findings.
Child↗
Structural analysis of peptide-acetaldehyde adducts by mass spectrometry and production of antibodies directed against nonreduced protein-acetaldehyde adducts.
Acetaldehyde can form protein-acetaldehyde adducts (AAs) in vivo and may play a role in the genesis of alcoholic liver disease. The nature of the chemical modification of proteins by acetaldehyde in vivo has not been elucidated. In vitro, acetaldehyde can form reversible adducts including a Schiff's base with lysine (K) and imidazolidinone with terminal amino groups of proteins such as human hemoglobin (Hb). In this study, we used FAB/MS to analyze the products of peptide-AAs (pep-AAs) formed by incubating acetaldehyde with Hb peptides. We then used an octabranched multiple antigen peptide (MAP) system containing Hb peptide-AAs to raise antibodies. Three Hb peptides [i.e., 8-pep consisting of 8 residues (V1HLTPVEK8) at the N-terminus of beta-chain of human sickle-cell Hb, 11-pep-gly consisting of 11 residues (G56NPKVKAHGKK66) in a segment of beta-chain rich in lysine, and 11-pep-pro that consists of the same sequence as 11-pep-gly, except G56 was replaced by proline (P)] were incubated with 1 mM acetaldehyde at 4 degrees C for 7d without NaCNBH3 (nonreduced conditions). Analysis by FAB/MS showed that 8-pep formed an imidazolidinone at the N-terminal valine, 11-pep-gly formed a Schiff's base and imidazolidinone at the N-terminus, whereas 11-pep-pro that lacks a free alpha-amino group formed only a Schiff's base at K59. By contrast, incubation of these Hb peptides with 250 mM acetaldehyde and NaCNBH3 at 37 degrees C for 1 hr (reduced conditions) produced mono- and diethylated modifications of all available K residues, as well as the N-terminal amino group.(ABSTRACT TRUNCATED AT 250 WORDS)
Acetaldehyde↗
Predictive factors in recurrent spontaneous aborters--a multicenter study.
PROBLEM: Compare data from several centers relating to success rates in recurrent spontaneous miscarriage and assess the significance of indicators of subsequent pregnancy loss. METHOD: Data from 777 couples with unexplained recurrent spontaneous abortion from independent studies at seven centers were analyzed using logistic regression analysis. The following covariates were considered: age of patient, number of previous spontaneous abortions, length of previous abortions history, sub-fertility index (defined as the product of the number of spontaneous abortions and the abortion history), whether a patient was a primary or secondary aborter, and whether a patient had received leukocyte immunotherapy. RESULTS: There was a highly significant difference between the seven centers in success rates in the subsequent pregnancy and a highly significant association between success rate and each of the following covariates: the number of previous abortions, the length of the previous abortion history and the sub-fertility index. In particular, for each increase of 10 units in the value of the sub-fertility index, up to a value of 30, the odds in favor of a successful pregnancy decreased by a factor of 0.6, i.e., 40%. There was, however, little evidence of an association between the success rate in the subsequent pregnancy and age, parity, or immunization with cells from the husband. CONCLUSIONS: The sub-fertility index may be a useful measure of likelihood of success in a subsequent pregnancy.
Abortion, Habitual↗
Fertility among women with recurrent spontaneous abortions--the effect of paternal cell immunization treatment.
PROBLEM: The risk of women whose chief complaint is recurrent spontaneous abortions (RSA) for secondary infertility (infecundability) has not been evaluated prospectively. The effect of paternal mononuclear cell immunization on conception rates is unknown. METHOD: Two hundred women whose chief complaint was RSA were randomly assigned to be immunized with paternal mononuclear cells either before or after (up to 6 postmenstrual weeks) conception. Fertility rates (both conception and live birth) were evaluated for the group immunized before conception and compared to those for the control group, who were not immunized until after conception, using life table and multiple logistic regression analyses. RESULTS: Prospectively ascertained, age-related conception rates for nonimmunized RSA controls appeared to be similar to those for general populations. Immunization before pregnancy had no significant effect (power +/- 14%) on rates of conception (66% before, 77% after) or time to conceive (median weeks before 19.5, after 27.0). Live birth rates (before 59%, after 63%) were also similar for both groups (P = 0.7). CONCLUSION: Women whose only prior complaint was RSA were not at high risk for secondary infecundability, and immunization did not alter either conception rates or time to conceive. Postponement of immunization until after conception did not affect live birth rates for women selected for study because they did not have a history of prior infecundability or early repeated miscarriages.
Abortion, Habitual↗
Isolation of decidual lymphocytes from chorionic villus samples: phenotypic analysis and growth in vitro.
PROBLEM: Giemsa stained cell isolates prepared from chorionic villus samples (CVS) contain granulated cells morphologically similar to large granular lymphocytes. METHOD: Phenotypic characterization of these cellular isolates by two-color immunofluorescence and subsequent in vitro culture in the presence of recombinant interleukin-2 (rIL-2) were done in order to determine whether CVS could serve as a source of decidual lymphocytes. RESULTS: A major fraction of the CVS-derived lymphocytes were characterized as decidual NK cells, exhibiting high levels of CD56 expression (CD56+bright), without concomitant expression of CD16. The T cell population present in CVS-derived lymphocytes contained both CD4+ and CD8+ cells in a ratio somewhat reduced compared to that found in peripheral blood. While both T cells and CD56+bright cells from CVS proliferate in vitro in response to rIL-2 alone, preferential growth of CD56+bright cells was accomplished using a selective culture technique wherein co-culture with an irradiated, B lymphoblastoid cell line promoted the growth of CD56+ cells. CONCLUSION: CVS contains decidual NK cells and T cells that proliferate in response to rIL-2 and/or third party stimulator cells. These culture techniques will allow investigations into the maturation and/or activation of decidual NK cells and T cells.
Antigens, CD↗
Alloantibody responses to antigens recognized by rabbit antitrophoblast antisera in trophoblast and mononuclear cell (MNC) membranes by primary aborting women before and after paternal leukocyte immunization.
PROBLEM: Because shared allogeneic antigens are expressed on peripheral blood lymphocytes, as well as trophoblasts, it has been proposed that lymphocyte transfusions may appropriately sensitize recurrent spontaneous aborters (RSA) to trophoblast and lead to pregnancy conservation. The degree to which these responses are affected by this treatment, however, has not been defined. METHOD: SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analyses were used to study the alloantibody responses in RSA patients both before and after immunization with paternal leukocytes (MNC) against membrane proteins isolated from peripheral blood mononuclear cells (MNC), first trimester and full term chorionic villi (CV). RESULTS: A distinct set of antigens with apparent molecular weights of 32, 36, 41, 63, 65, and 85 kDa was identified in both MNC and trophoblast membranes by rabbit anti-trophoblast antisera. In addition, a 55 kDa protein was recognized by MNC membranes. Thirty-eight percent of primary RSA sera recognized this 55 kDa protein. After paternal MNC immunization, all primary RSA samples displayed increased reactivity or produced antibodies to this 55 kDa protein when compared with preimmunization sera. The protein was identified as MCP using a rabbit polyclonal anti-MCP antisera. In contrast, reactivity to the other antigens present in the membrane preparations decreased after paternal MNC immunization. CONCLUSION: Changes in immune reactivity in RSA patients after paternal MNC immunization suggest that immunization alters serum immune reactivity to MNC and trophoblast shared antigens.
Abortion, Habitual↗
Phorbol esters downregulate expression of the sodium/calcium exchanger in renal epithelial cells.
The Na+/Ca2+ exchanger (NCE) contributes to Ca2+ reabsorption by connecting tubules of the nephron. A line of renal epithelial cells from monkey kidney (LLC-MK2) was used to investigate the regulation of NCE expression. After the activation of protein kinase C (PKC) by phorbol myristate acetate (PMA), NCE activity decreased exponentially by 75% in 48 h (half time approximately 19 h). PMA decreased NCE mRNA by 85% in 24 h. The decrease in NCE transcript preceded the downregulation of NCE activity. NCE protein was quantified with a monoclonal antibody to cardiac NCE. PMA decreased the binding of 3H-labeled antibody to cell sonicates by 40% in 24 h. Immunoblots show that PMA produced a marked and extended increase in membrane-associated PKC-alpha, although PMA depleted total PKC-alpha by 65% in 24 h. In vivo 32P labeling of myristolated alanine-rich C kinase substrate, a specific PKC substrate, confirmed that PMA produced a rapid and extended activation of PKC. 4 alpha-PMA, a stereoisomer of PMA that neither binds nor activates PKC, had no effect on NCE activity or transcript. These findings indicate that activation of PKC with phorbol esters downregulates NCE mRNA, protein, and activity in renal epithelial cells.
Animals↗
Activation of adenylyl cyclase downregulates sodium/calcium exchanger of arterial myocytes.
Chronic elevation of adenosine 3',5'-cyclic monophosphate (cAMP) is known to inhibit the proliferation of cultured vascular smooth muscle cells. The present findings show that the activation of adenylyl cyclase with forskolin decreased Na+/Ca2+ exchanger (NCX) mRNA and activity. Fetal bovine serum restored NCX transcript and activity. The changes in NCX transcript preceded the changes in NCX activity. Incubation of low-passage immortalized myocytes with forskolin plus 3-isobutyl-1-methylxanthine (IBMX), which inhibits cAMP phosphodiesterase, decreased NCX mRNA by 60% in 6 h and 80% in 24 h. After a 6-h lag, forskolin plus IBMX decreased NCX activity almost linearly to 20% of control at 40 h. 1,9-Dideoxyforskolin, which does not activate adenylyl cyclase, had no effect on NCX mRNA or activity. Forskolin plus IBMX decreased the c-Myc transcript, an immediate-early gene whose expression correlates with cell proliferation, but had no effect on plasma membrane Ca(2+)-ATPase transcripts. Removal of forskolin plus IBMX and addition of fetal bovine serum increased NCX and c-Myc transcripts seven- to eightfold in 6 h and restored NCX activity in 24 h. Inhibition of protein or RNA synthesis by cycloheximide or actinomycin D, respectively, prevented the increase in NCX mRNA. In contrast to blocking NCX induction, cycloheximide potentiated c-Myc induction by serum. Transcription factors that regulate myocyte growth may mediate the opposing influences of serum and forskolin on NCX mRNA and activity.
1-Methyl-3-isobutylxanthine↗
Mononuclear cell (MNC) subtypes in osteoarthritis synovial fluid. Comparison with MNC subtypes in rheumatoid arthritis synovial fluid.
OBJECTIVE: To examine mononuclear cell (MNC) subtypes in osteoarthritis (OA) synovial fluid (SF) and compare these results with MNC subtypes in SF from patients with rheumatoid arthritis (RA). METHODS: MNC were obtained from SF by gradient centrifugation with Ficoll-Hypaque. MNC subtypes were identified using color immunofluorescence with monoclonal antibody pairs and flow cytometry. RESULTS: Significantly lower percentages of CD3+ (p < 0.01) and CD4+ cells (p < 0.01) were found in patients with OA. No differences were noted between CD8+ cells and the CD4/CD8 ratio. Significantly higher percentages of CD14+ (p < 0.001) and CD16+/CD56+ (p < 0.001) were found in patients with OA. CONCLUSION: Significant differences in MNC subtypes in OA and RA were noted that may reflect differences in pathophysiologic mechanisms operational in each disease.
Aged↗
Racial differences in North Carolina infant mortality.
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Black or African American↗
Regulation of sodium-calcium exchanger by glucocorticoids and growth factors in vascular smooth muscle.
The findings presented in this paper indicate that glucocorticoids down-regulate Na(+)-Ca2+ exchanger (NCX) mRNA and activity in aortic myocytes. Serum and purified growth factors reversed NCX down-regulation. Dexamethasone, cortisol, or aldosterone decreased NCX activity by approximately 55% in 24 h. Dexamethasone was > 100 times more potent than aldosterone, indicating that a glucocorticoid receptor mediates the down-regulation of NCX activity. Dexamethasone decreased the NCX transcript to approximately 10% of the control level in 24 h without affecting plasma membrane Ca(2+)-ATPase transcripts. Fetal bovine serum increased NCX mRNA 10-fold in 4 h in dexamethasone-treated cells and restored full NCX activity in 16 h. The increase in NCX mRNA produced by serum required RNA and protein synthesis. Thrombin moderately increased NCX mRNA and partially restored NCX activity in dexamethasone-treated cells. Insulin, platelet-derived growth factor, or epidermal growth factor increased NCX mRNA similarly to thrombin. Tunicamycin, which inhibits N-linked glycosylation, prevented the restoration of NCX activity. These observations suggest that changes in the level of NCX mRNA mediate the opposing influences of glucocorticoids and growth factors on NCX activity. NCX induction by growth stimuli would increase the capacity for Ca2+ efflux and cycling between the cell and the environment.
Animals↗
Evidence for a role for tyrosine phosphorylation of phospholipase C gamma 2 in collagen-induced platelet cytosolic calcium mobilization.
(1) The non-specific protein kinase C inhibitor, staurosporine, inhibited collagen-induced increases in cytosolic free Ca2+ while having no effect on Ca2+ mobilization by other platelet agonists. A more specific inhibitor of protein kinase C, Ro 31-8220, did not inhibit collagen-induced Ca2+ mobilization. Neither drug had an effect on platelet adhesion to collagen. (2) Staurosporine inhibited collagen-stimulated tyrosine phosphorylation, while Ro 31-8220 had no effect. (3) It also inhibited collagen-induced phosphatidic acid formation, inositol trisphosphate formation and arachidonic acid liberation. (4) Ro 31-8220 did not inhibit collagen-stimulated arachidonic acid formation, but it enhanced collagen-stimulated phosphatidic acid and inositol trisphosphate formation. (5) Immunoprecipitation of phospholipase C gamma 2 (PLC gamma 2) with a specific antibody demonstrated that PLC gamma 2 was phosphorylated on tyrosine after stimulation by collagen. (6) The phosphorylation of PLC gamma 2 was inhibited by staurosporine but not by Ro 31-8220. These results provide additional evidence that the mechanism of signal transduction for collagen is different from other platelet agonists and indicate that it involves activation of PLC gamma through a tyrosine kinase-dependent mechanism.
Alkaloids↗
Site selectivity in the glycation of alpha A- and alpha B-crystallins by glucose.
We determined the site selectivity of glycation by glucose (glucosylation) in alpha A- and alpha B-crystallins using two independent approaches. HPLC purified 14C-glucose labeled chymotryptic peptides and affinity chromatography/HPLC purified fully glycated peptides were identified by FAB-MS. Lys 11 and 78 of alpha A-crystallin and Lys 90 and/or 92 of alpha B-crystallin were the fast reacting sites of glucosylation.
Animals↗
Post-translational modifications of water-soluble human lens crystallins from young adults.
Post-translational modifications of the water-soluble human lens crystallins from young adult donors were identified and located using electrospray ionization mass spectrometric analysis of the intact proteins and fast atom bombardment mass spectrometry of enzymatic digests. Peptides corresponding to all of the sequences of alpha A-, alpha B-, and beta B2-crystallins were found, permitting the entire sequences to be searched for modifications. The major portions of these three crystallins were not modified. Modifications of alpha A-crystallin that were detected included 2 phosphorylated Ser residues (1 of which appears to be unique to human lenses), deamidation at some Gln and Asn residues, a disulfide bond between Cys-131 and Cys-142, and loss of the COOH-terminal Ser residue. Three phosphorylated Ser residues, but no deamidation, were found in alpha B-crystallin. The molecular weights of neither the intact protein nor the peptides in the enzymatic digests indicated any post-translational modification of the principal beta-crystallin, beta B2. The molecular weights of the other beta- and gamma-crystallins for which sequences have been published suggested the presence of post-translational modifications or errors in the published sequences. Although enough peptides were found to establish the presence of specific proteins, peptides corresponding to all portions of these proteins were not found, and elucidation of these structures is not yet complete. This mass spectrometric characterization of the total water-soluble proteins from normal young adult lenses provides a reference data base for future investigations of the modifications present in aged and cataractous lenses.
Adult↗
Evidence that alternate foldings of the hepatitis delta RNA confer varying rates of self-cleavage.
The pentapurine sequence GGAGA, located between 80 and 84 nucleotides downstream of the cleavage site in the self-cleaving antigenomic RNA of hepatitis delta virus, is necessary for highly efficient cleavage and for stability in up to 20 M formamide. Yet much of the cleavage activity lost upon its removal from the 3' end of an 84-nucleotide RNA can be restored by elongation of the 5' end of the RNA with the polypyrimidine sequence found in the virus. We propose that this sequence alteration causes a refolding of the RNA, resulting in a "structural compensation" of the active core of the molecule. Restoration of the self-cleavage activity did not restore the ability to cleave in high concentrations of formamide. Deletion mutagenesis was carried out and supported the alternate RNA folding. The ability to assume more than one active conformation and for one RNA structure to compensate for another in supporting ribozyme activity may be unique to RNA enzymes and could be a useful adaptation in viruses or in prebiotic RNAs.
Base Sequence↗
Platelet aggregation abnormalities after cardiopulmonary bypass.
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Cardiopulmonary Bypass↗