Oestrogens and depression.
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Depressive Disorder↗
Biomedical subjects
J Rivera
Publications and source records attributed to J Rivera.
Differential effects of the protein kinase C activator phorbol 12-myristate 13-acetate on calcium responses and secretion in adherent and suspended RBL-2H3 mucosal mast cells.
Adhesion of RBL-2H3 mucosal mast cells to fibronectin-coated surfaces has been linked to changes in secretion and tyrosine kinase activity. We now show that adhesion affects the sensitivity of RBL cells to the protein kinase C activator phorbol 12-myristate 13-acetate (PMA). In suspended cells, PMA inhibited antigen-induced calcium influx (as measured by manganese influx) and changes in intracellular free calcium and had complex effects on antigen-stimulated secretion. However, in adherent cells PMA had little effect on these responses. Suspended cells only secreted in response to thapsigargin if they were co-treated with PMA, while adherent cells secreted in response to thapsigargin alone. The thapsigargin-induced secretion in adherent cells was inhibited by protein kinase C down-regulation and by the protein kinase C inhibitor GF 109203X, but not by calphostin C. We suggest that protein kinase C is constitutively activated in adherent cells, possibly due to modification of the regulatory domain of the enzyme.
Animals↗
Organochlorine pesticide residues in adipose tissue of Mexicans.
Concentrations of organochlorine insecticide residues such as DDT, DDE, gamma- and beta-HCH were determined in human adipose tissue samples obtained during autopsies from urban and suburban areas of Veracruz city, the state of Veracruz and out-of-state areas, collected during 1988 and 1991. The mean levels of total DDT, which constitutes the predominant accumulated pesticide, decreased from 17.45 mg/kg in 1988 to 14.06 mg/kg in 1991. The highest levels of total DDT were determined in persons from suburban areas of Veracruz city and among persons over 51 years old with the highest levels of contamination observed in patients dying of cardiovascular disorders.
Adipose Tissue↗
Aggregation of the Fc epsilon RI in mast cells induces the synthesis of Fos-interacting protein and increases its DNA binding-activity: the dependence on protein kinase C-beta.
The ability of c-Fos to dimerize with various proteins creates transcription complexes which can exert their regulatory function on a variety of genes. One of the transcription factors that binds to c-Fos is the newly discovered Fos-interacting protein (FIP). In this report we present evidence for the regulation of the synthesis of FIP by a physiological stimulus. We found that the aggregation of the mast cell high affinity receptor for IgE (Fc epsilon RI) induced the synthesis of FIP and increased its DNA binding activity. Moreover, down-regulation of the isoenzyme protein kinase C-beta (PKC-beta) by a specific antisense phosphorothioate oligonucleotide resulted in profound inhibition of FIP-Fos DNA binding activity. Thus, aggregation of the Fc epsilon RI on mast cells elicits a PKC-beta dependent signaling pathway which regulates FIP-Fos DNA binding activity.
Animals↗
Analgesic efficacy of controlled-release oxycodone in postoperative pain.
The efficacy and safety of graded doses (10, 20, and 30 mg) of controlled-release (CR) oxycodone was compared with that of immediate-release (IR) oxycodone (15 mg), immediate-release oxycodone 10 mg in combination with acetaminophen 650 mg (APAP), and placebo in a single-dose, double-blind, randomized, parallel-group study. The participants, 182 inpatients experiencing moderate to severe pain after abdominal or gynecologic surgery, provided hourly ratings of pain intensity and relief for 12 hours after administration. All active treatments were significantly superior to placebo for many hourly measurements and for the sum of pain intensity differences (SPID) and total pain relief (TOTPAR). A dose response was found among the three levels of CR oxycodone for pain relief and peak pain intensity difference (PID), with the 20- and 30-mg doses being significantly better than the 10-mg dose. For all active treatments, peak PID and peak pain relief occurred approximately 2 to 4 hours after administration. The median time to onset of relief was 32 minutes for oxycodone plus APAP, 41 minutes for IR oxycodone, and 46 minutes for CR oxycodone 30 mg. Duration of pain relief showed that the 10-, 20-, and 30-mg doses of CR oxycodone had durations of action of 10 to 12 hours compared with IR oxycodone and oxycodone plus APAP (both approximately 7 hours). Typical adverse events, particularly somnolence, occurred in all active treatment groups. Treatment with CR oxycodone was safe and effective in this study, and its characteristics will be beneficial in the treatment of pain.
Acetaminophen↗
Organochlorine pesticide residues in human breast milk from tropical areas in Mexico.
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Adolescent↗
Estimated intake of PCDDs, PCDFs and co-planar PCBs in individuals from Madrid (Spain) eating an average diet.
The estimated intake of PCDD/Fs and co-planar PCBs associated with an average diet consumed in Spain was investigated. The estimated total average intake for PCDDs and PCDFs from an average spanish diet was found to be 142 pg I-TEQ/day (2.4 pg I-TEQ/Kg b.w./day, for a 60 Kg person). PCDDs provided almost 80% of the total dioxin equivalents. This represents the upper bound estimate. If concentrations less than the LOD are taken as equal to zero, then the estimated average intake would be 81 pg I-TEQ/day which is the lower bound estimate. Data reported are in good agreement with those reported for other countries.
Benzofurans↗
Changes in the phosphorylation of eukaryotic initiation factor 2 alpha, initiation factor 2B activity and translational rates in primary neuronal cultures under different physiological growing conditions.
Phosphorylation of the alpha-subunit of eukaryotic initiation factor 2 (eIF-2) is one of the best known mechanisms regulating protein synthesis in a wide range of eukaryotic cells, from yeast to human. To determine whether this mechanism operates in primary neuronal cells, we have cultured primary neuronal cells for 7 days under two optimal growing conditions, complete medium (containing 15% serum) and serum-free medium, and determined the protein synthesis rate, eukaryotic initiation 2 and 2B (eIF-2B) activities, as well as the level of phosphorylation of eIF-2. Cells cultured in serum-free medium exhibited a lower rate of protein synthesis (75%), concomitant to a decreased eIF-2 activity (71%), and slightly higher eIF-2(alpha P) levels (from 10 to 16% of total eIF-2) with respect to cells cultured in complete media. eIF-2B activity, as measured at saturating eIF-2. GDP concentrations (assay independent on the presence of eIF-2(alpha P)) was similar under the two culture conditions. When neurons cultured in serum-free medium are exposed to complete medium for only 24 h, there is a clear decrease in the phosphorylation of eIF-2 alpha (16-3%). This decrease correlates in time with an increase in the protein synthesis rate (154%), as well as eIF-2 activity (236%). The increased levels of eIF-2(alpha P), a competitive inhibitor of eIF-2B in the guanine-exchange reaction, are responsible for the decreased eIF-2B activity found in the neurons cultured in serum-free medium. Additionally, eIF-2(alpha P) is accountable for the lower effect of exogenous eIF-2B in ternary complex formation from preformed eIF-2. GDP in the serum-free media. These changes in phosphorylation of eIF-2 alpha in normal mammalian cells in response to changes in the extracellular medium are reported here for the first time.
Animals↗
Association of autoantibodies against platelet glycoproteins Ib/IX and IIb/IIIa, and platelet-reactive anti-HIV antibodies in thrombocytopenic narcotic addicts.
The levels of platelet-associated Igs (PAIgs) and plasma circulating antiplatelet antibodies were evaluated by a flow cytometric immunofluorescence assay (FCIFA), an enzyme-linked immunoassay (ELISA), and a platelet radioactive antiglobulin test (PRAT), in a group of 45 human immunodeficiency virus (HIV)-infected intravenous drug users (IVDUs), with or without thrombocytopenia (TCP). Direct tests demonstrated an increased amount of PAIgs in 40% of the patients, irrespective of their platelet count. These PAIgs were mainly of IgG class and could not be eluted with ether. Plasma IgG with antiplatelet activity was found in 70% of the thrombocytopenic individuals, whereas it was detected in only one patient without TCP. The relative frequencies of antibodies against the platelet glycoproteins (GPs) Ib/IX and IIb/IIIa were assessed in plasma from all patients by means of the monoclonal antibody-specific immobilization of platelet antigens assay (MAIPA). Plasmas from all non-thrombocytopenic patients were negative when tested by indirect MAIPA. In contrast, 10/23 plasma from thrombocytopenic patients reacted with either GP IIb/IIIa, GP Ib/IX, or both GPs. Finally, aiming to investigate whether HIV antibodies from these patients are reactive with normal platelets, we performed absorption-elution experiments, followed by evaluation of HIV antibodies in the indirect eluates by ELISA and Western blot. Interestingly, we detected anti-HIV antibodies that bind to normal platelet antigens in 50% of the ether eluates prepared from control platelets sensitized with plasma from patients with TCP, but in only 5% of eluates obtained from platelets sensitized with plasma from non-thrombocytopenic patients. The present study provides direct evidence that specific autoantibodies against platelet membrane GPs Ib/IX and IIb/IIIa are common in HIV positive thrombocytopenic individuals. The finding in these patients of HIV antibodies cross-reactive with normal platelets, suggests that mimicry of human antigens by HIV could play a key role in the pathophysiology of the HIV-related TCP.
Adult↗
Fecal screening tests in the approach to acute infectious diarrhea: a scientific overview.
OBJECTIVE: To evaluate the value of fecal leukocytes, fecal occult blood, fecal lactoferrin and combination of fecal leukocytes with clinical data in the workup of patients with inflammatory diarrhea. DATA IDENTIFICATION: A systematic literature search in all languages using MEDLINE (1970 to 1994), reference lists of articles primarily retrieved and of review articles and correspondence with experts in the field. STUDY SELECTION: The search identified 2603 references, 81 of which were deemed relevant on the basis of prespecified selection criteria. Of these 25 contained sufficient data for further analysis and thus were finally included. DATA EXTRACTION: All data from the selected articles were extracted by one observer whereas the second reviewer checked these data for accuracy. True positive rates and false positive rates were calculated from each 2 x 2 table. RESULTS OF DATA ANALYSIS: The study summarizes the diagnostic accuracy of the signaled tests as predictors of inflammatory diarrhea as defined by stool culture (the reference test). Plots of true positive rates against false positive rates demonstrated widely scattered points, indicating heterogeneity. A summary receiver operating characteristic curve was fitted to the data with the use of logistic transforms and weighted least squares linear regression. Of the 25 studies analyzed 38 data points were used to construct summary receiver operating characteristic curves for index tests. CONCLUSIONS: Fecal lactoferrin was the most accurate index test. Fecal leukocytes showed the lowest performance as assessed by the area under the curve. Occult blood and combination of fecal leukocytes with clinical data yielded intermediate curves. A limited number of studies (fecal lactoferrin, and fecal leukocytes with clinical data) and methodologic flaws identified in the assessed studies must be solved in future primary studies to improve the usefulness of the metaanalytic approach used here.
Blood↗
Cyclic guanosine 3',5' monophosphate concentrations in pre-eclampsia: effects of hydralazine.
OBJECTIVE: To elucidate the role of the L-arginine:nitric oxide pathway in pregnancy and pre-eclampsia. PARTICIPANTS: Pregnant women (nulliparous, age <25 years). Normotensive pregnancy (n=22) was defined when blood pressure remained at levels of <120/80 mmHg and there was no proteinuria. Women with pre-eclampsia (n=22) had blood pressure measurements of >140/90 mmHg and proteinuria of >300 mg/l. Nonpregnant normotensive women (n=22) were studied as controls. STUDY DESIGN: Blood samples were taken for measurements of ionised calcium, atrial natriuretic factor, cyclic guanosine 3'5' monophosphate (GMP),arginine and asymmetric dimethylarginine. Urine samples were collected for determination of cyclic GMP excretion. Cyclic GMP concentrations were also determined in 12 women with severe pre-eclampsia before and after treatment with hydralazine. RESULTS: L-arginine, asymmetric dimethylarginine and atrial natriuretic factor were not different in any group. Cyclic GMP concentrations in plasma [0.94 (SD 0.23) nM] as well as in urine [50.1 (SD 15.7) microM] were increased significantly (P<0.05) in normal pregnancy compared to nonpregnant controls [plasma mean 0.46 (SD 0.12) nM and urine mean 18.4 (SD 10.3) microM], but not in the pre-eclampsia group [plasma mean 0.48 (SD 0.10) nM and urine mean 24.1 (SD 14.5) microM]. Concentrations of cyclic GMP in plasma and urine increased significantly (P<0.05) in women treated with hydralazine. CONCLUSIONS: The differences in cyclic GMP concentrations may reflect differences in nitric oxide production. Hydralazine increases cyclic GMP concentrations in severely pre-eclamptic women. This action could explain the antihypertensive effect of hydralazine.
Adult↗
Early nutrition and later physical work capacity.
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Adolescent↗
Comparative study of three methods to detect free plasma antiplatelet antibodies.
We have compared three techniques for the detection of plasma circulating antiplatelet antibodies, i.e., the platelet suspension immunofluorescence test (PSIFT), the platelet radioactive antiglobulin test (PRAT), and the monoclonal antibody immobilization of platelet antigens (MAIPA). Frozen plasma samples from patients with idiopathic thrombocytopenic purpura or HIV-associated thrombocytopenia were used in the study. The PSIFT and PRAT showed the appropriate ease of performance necessary for screening purposes. The PSIFT is free of radioactivity hazards, but seemed to be less sensitive than the PRAT. The MAIPA is a useful tool to detect antibodies against glycoproteins (GPs) Ib/IX and IIb/IIIa. However, in comparison to PSIFT and PRAT, MAIPA is more time consuming, requires considerable technical expertise, and the identification of antiplatelet activity is highly dependent on the selection of an appropriate primary anti-GP monoclonal antibody. This could explain the lower prevalence of antiplatelet activity detected by MAIPA, in comparison to the frequency provided by the PSIFT and PRAT.
Antibodies, Monoclonal↗
[A case of hemorrhagic rectocolitis associated with the presence of intestinal spirochetes].
We report a case of a girl of 14 years old who developed a rapidly fatal chronic hemorrhagic rectocolitis. Several colonic biopsy specimens were studied by using the Vago stain. They showed many spirochetes attached end-to-end to the colonic epithelium. While the demonstration of a causal relationship between the intestinal symptoms and the presence of these spirochetes warrants further studies, the present observation outlines the need of researching this type of microorganisms through stains such as Vago stain whenever physicians are confronted with chronic intestinal inflammatory syndromes.
Adolescent↗
Phosphorylation of initiation factor 2 alpha subunit and apoptosis in Ca2+ ionophore-treated cultured neuronal cells.
The initial step of protein synthesis is regulated by the eukaryotic initiation factor 2 (eIF-2) whose phosphorylation in the alpha subunit by specific kinases, as double-stranded RNA-dependent protein kinase (PKR), produces an inhibition of the translational rates. Besides, intracellular Ca2+ mobilization has been associated with an increase in the PKR activity. Our results show, in primary neuronal cultures, that the treatment with the Ca2+ ionophore A23187 induces an increase in the phosphorylation of the alpha subunit of eIF-2 (eIF-2 alpha) and inhibition of protein synthesis. Those biochemical changes run parallel to the appearance of specific apoptosis characteristics such as cell shrinkage, segmentation of chromatin into small round bodies, and cleavage of DNA into 180 bp multimers. These results indicate that one of the targets during the process of apoptosis induced by the rise in the intracellular Ca2+, could be eIF-2 factor.
Animals↗
[Subcutaneous administration of desmopressin to plasma donors: a controlled study].
BACKGROUND: The aim of the present controlled study was to assess the effect of subcutaneous administration of desmopressin acetate (DDAVP) on the yield of Factor VIII (FVIII) and von Willebrand Factor (vWF) obtained in cryoprecipitates after plasmapheresis collection. SUBJECTS AND METHODS: Fifteen plasma donors underwent twice plasmapheresis collections using an "Autophereses C. model A-201" and cryoprecipitates were prepared using standard methods. In every subject of study one of the procedure was performed 35 min after subcutaneous administration of DDAVP (0.3 micrograms/kg), obtained from a highly concentrated preparation of the drug (40 micrograms/ml). Prior to the other apheresis procedure no chemicals were administered. Evaluation of FVIII and vWF levels was performed in peripheral blood samples obtained at different time points and cryoprecipitates product samples. RESULTS: Administration of DDAVP led to two-fold increase the yield of FVIII and vWF immediately before the performance of plasmapheresis. DDAVP stimulation resulted in an increase in the yield of FVIII and vWF in cryoprecipitates, compared with levels in the absence of the drug (703 +/- 53 and 768 +/- 51 U versus 227 +/- 12 and 362 +/- 20 U, respectively). No adverse effects but flushing were observed after DDAVP administration. CONCLUSIONS: Subcutaneous administration of DDAVP prior to plasma collection is a safe method to improve drastically the content of FVIII and vWF in cryoprecipitates. This procedure should be considered as an useful tool to help in providing self-sufficiency of plasma.
Adult↗
Tyrosine phosphorylation of protein kinase C-delta in response to the activation of the high-affinity receptor for immunoglobulin E modifies its substrate recognition.
The delta isoform of protein kinase C is phosphorylated on tyrosine in response to antigen activation of the high-affinity receptor for immunoglobulin E. While protein kinase C-delta associates with and phosphorylates this receptor, immunoprecipitation of the receptor revealed that little, if any, tyrosine-phosphorylated protein kinase C-delta is receptor associated. In vitro kinase assays with immunoprecipitated tyrosine-phosphorylated protein kinase C-delta showed that the modified enzyme had diminished activity toward the receptor gamma-chain peptide as a substrate but not toward histones or myelin basic protein peptide. We propose a model in which the tyrosine phosphorylation of protein kinase C-delta regulates the kinase specificity toward a given substrate. This may represent a general mechanism by which in vivo protein kinase activities are regulated in response to external stimuli.
Animals↗
Development of a rapid approach to identification of tyrosine phosphorylation sites: application to PKC delta phosphorylated upon activation of the high affinity receptor for IgE in rat basophilic leukemia cells.
In rat basophilic leukemia cells (RBL-2H3) activation of the high affinity receptor for IgE induces tyrosine phosphorylation of PKC delta. We carried out solid phase synthesis of 15 amino acid long oligopeptides corresponding to the sequences around each of the 19 tyrosine residues in PKC delta. Only three oligopeptides, corresponding to tyrosine 52, 155, and 565, were phosphorylated when exposed to lyn kinase. Single mutants in each of these three tyrosine residues of PKC delta were prepared. Upon expression in the RBL-2H3 cells, only the mutant in tryosine 52 showed abolition of the IgE-antigen induced tyrosine phosphorylation.
Amino Acid Sequence↗