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Biomedical subjects

E Shea

Publications and source records attributed to E Shea.

11 recordsLinked to original sources
PubMed2001

ERK mediates effects of glycated albumin in mesangial cells.

The alterations in glomerular cell biology induced by glycated albumin resemble those caused by high ambient glucose, but are operative in physiologic (5.5 mM) glucose concentration. Recently, high glucose has been shown to activate extracellular signal-related kinase (ERK) in mesangial cells, but whether the mitogen-activated protein kinase (MAPK) cascade participates in signal transduction triggered by glycated albumin is unknown. Using a specific inhibitor of MAPK/ERK kinase, we demonstrate for the first time that activation of ERK is required for the inhibition of cell growth and enhanced elaboration of extracellular matrix protein provoked by glycated albumin. These findings indicate that the MAPK/ERK pathway mediates biologic activities of this glycated protein.

Animals↗
PubMed2000

Estimating K(oc) for persistent organic pollutants: limitations of correlations with K(ow).

The n-octanol/water partition coefficient (K(ow)) is commonly used to predict the soil or aquatic particle water partition coefficient normalized to organic carbon (K(oc)). Many correlations are available covering several chemical classes and ranges of hydrophobicity. This work indicates the K(ow) may not be a strong predictor for persistent organic pollutants (POPs) which are defined here as chemicals with logK(ow) > 5.0. In addition, the correlation developed in this work for POPs will still result in a predicted value which is of by a factor of 15. Accordingly, care must be taken when applying K(oc) estimations using K(ow) for POPs until more suitable correlations are developed.

DDT↗
PubMed1993

Glycated LDL concentrations in non-diabetic and diabetic subjects measured with monoclonal antibodies reactive with glycated apolipoprotein B epitopes.

The potential importance of the non-enzymatic glycation of low density lipoproteins (LDL) in atherogenesis and in the accelerated atherosclerosis associated with diabetes is well recognized. However, it has been difficult to evaluate LDL glycation in the clinical setting because of the lack of suitable methods. To approach this problem, we produced monoclonal antibodies, designated ES12, that recognize glycated apolipoprotein B epitopes in the LDL complex in human plasma. Here we report the use of these antibodies in a competitive enzyme-linked immunosorbent assay (ELISA) to measure glycated LDL concentrations in plasma from non-diabetic and diabetic subjects. In this assay, glycated LDL in the soluble phase inhibits binding of the ES12 antibody to glycated LDL immobilized to microtitre wells, whereas other glycated proteins and non-glycated LDL do not compete. A linear dose-response relationship for 10-125 ng glycated LDL per well allows the construction of standard curves, from which the concentration of glycated LDL in human plasma can be determined. The mean concentration of glycated LDL in samples from non-diabetic subjects was 21.8 +/- 0.9 mg/l, increasing to 40.8 +/- 2.6 mg/l in samples from patients with type II diabetes, comprising 1.9-4.8% and 3.2-14.8%, respectively, of total apolipoprotein B. Glycated LDL concentrations in samples from diabetic patients correlated positively and significantly with other indices of glycaemic status. The results indicate that circulating glycated LDL, which may have diagnostic and pathophysiologic importance, is increased in diabetes with attendant hyperglycaemia. The results further indicate that the described monoclonal antibody-based competitive ELISA affords a simple and reproducible method for quantitative measurement of glycated LDL.

Animals↗
PubMed1991

Production and characterization of monoclonal antibodies against non-A1c glycated hemoglobin.

Hybridomas secreting monoclonal antibodies specific for hemoglobin nonenzymatically glycated in the non-A1c position were produced by fusion of SP 2/0 myeloma cells with spleen cells from BALB/c mice immunized with nonenzymatically glycated hemoglobin prepared from human erythrocytes. Wells containing hydridomas secreting antibodies against glycohemoglobin were identified by binding, in an enzyme-linked immunosorbent assay, to purified glycated hemoglobin. The colony designated E85, which secreted antibodies discriminating between glycated versus unglycated hemoglobin, was cloned at least four times by limiting dilution and used for further study, performed with purified monoclonal antibody. Specificity of E85 was demonstrated by immunoblotting and by ELISA, wherein the monoclonal antibody reacted with glycated hemoglobin but not with hemoglobin A1c or with unglycated hemoglobin. Immunoblotting of human plasma with E85 on nitrocellulose yielded no reactive proteins, indicating site specificity for glycated epitopes residing in hemoglobin but not in other nonenzymatically glycated proteins present in plasma. E85 differs from other antibodies raised against glycated hemoglobin and other glycated proteins, which recognize hemoglobin glycated at the N terminal valine of the beta chain (HbA1c) or which recognize glycated residues only after reductive conversion to glucitollysine and which do not discriminate between different glycated proteins. Thus, this report describes the establishment of the first hybridoma secreting monoclonal antibody raised against a physiologic (unreduced) form of non-A1c glycohemoglobin, and for the glycated epitope when it resides in glycohemoglobin but not in other proteins or in hemoglobin A1c.

Antibodies, Monoclonal↗
PubMed1986

Integrin (the CSAT antigen): functionality requires oligomeric integrity.

Integrin, the cell-substrate attachment (CSAT) antigen, is a complex of integral membrane glycoproteins whose apparent function is to mediate cell-substratum adhesion by serving as a transmembrane link between the extracellular matrix and elements of the cytoskeleton. Previous attempts to separate the members of this complex under nondenaturing conditions have been successful. We have now produced a monoclonal antibody "G" that is specific for the lower molecular mass cysteine-rich band 3 of the complex. Using an antibody affinity column containing this monoclonal antibody, it is possible to dissociate integrin into two fractions, one containing band 3, the other containing bands 1 plus 2. Neither fraction will by itself bind fibronectin, laminin, or talin. However, when the fractions are combined, the reconstituted integrin elutes from a gel filtration column in the same position as the native complex, and binding activity to these molecules returns. Further, it is shown by gel filtration that the recognition site for the adhesion-disrupting monoclonal antibodies CSAT and JG22 is on band 3, supporting the contention that integrin is an oligomer. The data presented here is consistent with integrin being either a mixture of heterodimers, each with a common subunit and reacting with a particular extracellular matrix molecule, or a single heterotrimer capable of binding to several different extracellular matrix molecules.

Animals↗
PubMed1979

A prospective study of the oxytocin challenge test and newborn neurobehavioral outcome.

In a prospective study, infants of high-risk mothers delivered over a 1-year period were evaluated by clinical, biochemical, and behavioral methods. Of 67 newborns whose mothers had oxytocin challenge tests (OCTs), 54 were delivered after negative tests, and 13 after positive tests. Infants with positive OCTs had poor state organization and reflexive performance when compared with negative-OCT babies. These infants also showed evidence of intrauterine malnutrition, but did not have any greater asphyxiation than the negative OCT group. These results are consistent with the hypothesis that a positive OCT implies pathological placental respiratory insufficiency, which may be superimposed, in many instances, on impairment in utero of the placenta's nutritional function. The clinical manifestation of such dysfunction is the alteration in subtle neonatal neurobehavior.

Behavior↗
PubMed1978

Clinical and neurobehavioral effects of repeated intrauterine exposure to oxytocin: a prospective study.

A prospective investigation of 114 pregnant women compared 54 with consistently negative oxytocin challenge tests to 60 women who did not have oxytocin challenge tests but did have fetal monitoring during labor. Despite more high risk factors in the OCT group, there were no significant differences noted in the offspring. Specifically, extensive behavioral testing during the first 12 hours of life and at 3 days of age did not show any abnormalities. Furthermore, jaundice and respiratory distress were not seen more often after oxytocin exposure. These data argue that the OCT itself is without demonstrable adverse effects on the otherwise healthy fetus.

Adult↗
PubMedDate not supplied

An evaluation of breastfeeding promotion literature: does it really promote breastfeeding?

Breastfeeding pamphlets are being produced for new mothers by both commercial and nonprofit sources in increasing quantities. A regional lactation committee decided to evaluate these materials on the basis of accuracy, degree of positive approach to breastfeeding, readability and compliance with the WHO/UNICEF Code on the Marketing of Breast Milk Substitutes. Results indicate that materials produced by non-profit sources scored higher in positive approach accuracy and WHO Code compliance compared with commercial sources. Only 2 of 22 pamphlets in the sample were written within the recommended reading level of Grade 5-8. None of the materials met all of the criteria for good promotional breastfeeding literature.

Attitude to Health↗