PubMed Health⌕ Search

Biomedical subjects

E Ling

Publications and source records attributed to E Ling.

At least 37 records · Page 2Linked to original sources
PubMed1993

Concentration of endometrial protein PP14 in uterine flushings throughout the menstrual cycle in normal, fertile women.

OBJECTIVE: To determine the variation in concentration of endometrial protein PP14 in uterine flushings throughout the menstrual cycle comparing this to concentrations in plasma samples. DESIGN: Precise timing of all samples by the luteinising hormone surge. SETTING: Jessop Hospital for Women, Sheffield. SUBJECTS: Twenty-three regularly cycling, previously fertile volunteer women. INTERVENTIONS: Observational study; 10 ml of physiological saline was used to flush the uterine cavity once or serially in the cycle of the study. MAIN OUTCOME MEASURES: The measurement of PP14 levels by radioimmunoassay in uterine flushings and plasma samples. RESULTS: In uterine flushing, PP14 levels were not detectable in significant amounts in the proliferative phase and the early luteal phase; after day LH + 6, the concentration rises rapidly with a doubling time of only 6.6 to 14.6 h in the midluteal phase. In the late luteal phase, the concentrations in uterine flushing were over a hundred times higher than the corresponding plasma samples. CONCLUSIONS: The measurement of PP14 in uterine flushings is likely to be of greater value than the measurement in plasma samples; it may provide a valuable alternative to the evaluation of endometrial function.

Adult↗
PubMed1992

An analysis of the variation of plasma concentrations of placental protein 14 in artificial cycles.

OBJECTIVE: To analyze the factors affecting the variation of plasma concentration of placental protein 14 (PP14) in artificial cycles. DESIGN: The effects of different hormone replacement therapy (HRT) regimens were examined in a crossover design. SETTING: Jessop Hospital for Women, Sheffield, United Kingdom. PATIENTS: Eighteen women with premature ovarian failure: 6 associated with Turner's syndrome and 12 with idiopathic premature ovarian failure. INTERVENTIONS: Four different HRT regimens; 36 study cycles. MAIN OUTCOME MEASURES: Plasma PP14 concentrations on days 1, 15, 19, and 29 of the artificial cycles. RESULTS: In cycles treated with a standard HRT, the levels were similar to those of the natural cycle. Subjects with Turner's syndrome did not have elevated PP14 levels, whereas the majority (9/12 [75%]) of those with idiopathic premature ovarian failure had elevated levels on day 29 of the cycle. Levels of PP14 were reduced when either the doses of estradiol valerate were reduced to 1/3 or the doses of progesterone (P) were reduced to 1/5 of the standard HRT. CONCLUSIONS: Plasma levels of PP14 are dependent not only on P stimulation but also on adequate estrogen priming.

Adult↗
PubMed1991

Optimal positioning of endotracheal tubes for ventilation of preterm infants.

Accurate knowledge of upper-airway dimensions is required to prevent malpositioning of endotracheal tubes in preterm infants. We measured vocal cord-carina, oral-carina, and nasal-carina distances in situ at autopsy of two groups of infants (less than 1000 and greater than or equal to 1000 g). In all 24 infants, crown-heel length, crown-rump length, and occipitofrontal circumference were better than weight in predicting upper-airway dimensions. Flexion of the neck decreased and extension increased both nasal-carina and oral-carina distances. Lateral rotation produced no significant changes. The postmortem data were not different from nasal-carina distances measured radiologically in 40 living, nasally intubated and ventilated infants, confirming the clinical validity of our findings. Regression equations were derived to predict optimal endotracheal tube lengths based on the external measurements of crown-rump length and crown-heel length.

Body Height↗
PubMed1991

Failure of supplementation with vitamin E to prevent bronchopulmonary dysplasia in infants less than 1,500 g birth weight.

In a randomized trial to determine whether oral vitamin E reduced stages III and IV bronchopulmonary dysplasia (BPD) by 50%, 268 infants were randomly allocated, after stratification by birth weight and severity of disease, to receive vitamin E 25 units or an indistinguishable placebo. The experimental (E) group and the control (C) group were similar in weight, gestational ages, Apgar scores, severity of illness, and initial oxygen and ventilator exposure. Serum vitamin E levels were significantly different within 48 h of administration and remained well above normal adult levels from the first week of life in the experimental group. There was no difference in the rates of early death, BPD at 28 days, or mortality from BPD. Severity was similar and no difference was seen in the incidence of necrotizing enterocolitis or sepsis. There was no evidence that vitamin E supplementation offered protection against chronic lung disease in infants less than 1,500 g birth weight.

Bronchopulmonary Dysplasia↗
PubMed1990

Selective modulation of band 4.1 binding to erythrocyte membranes by protein kinase C.

We have studied the effects of band 4.1 phosphorylation on its association with red cell inside-out vesicles stripped of all peripheral proteins. Band 4.1 bound to these vesicles in a saturable manner, and binding was characterized by a linear Scatchard plot with an apparent Kd of 1-2 x 10(-7) M. Phosphorylation of band 4.1 by purified protein kinase C reduced its ability to bind to membranes, resulting in a reduction in the apparent binding capacity of the membrane by 60-70% but little or no change in the apparent Kd of binding. By contrast, phosphorylation of band 4.1 by cAMP-dependent kinase had no effect on membrane binding. Digestion of the stripped inside-out vesicles with trypsin cleaved 100% of the cytoplasmic domain of band 3 but had little or no effect on glycophorin. Binding of band 4.1 to these digested vesicles was reduced by 70%. Phosphorylation of band 4.1 by protein kinase C had no effect on its binding to the digested vesicles, suggesting that the cytoplasmic domain of band 3 contained the phosphorylation-sensitive binding sites. This was confirmed by direct measurement of band 4.1 binding to the purified cytoplasmic domain of band 3. Phosphorylation of band 4.1 by protein kinase C reduced its binding to the purified 43-kDa domain by as much as 90%, while phosphorylation by cAMP-dependent kinase was without effect. These results show a selective effect of protein kinase C phosphorylation on the binding of band 4.1 to one of its membrane receptors, band 3, and suggest a mechanism whereby one of the key red cell-skeletal membrane associations may be modulated.

Cytoskeletal Proteins↗
PubMed1990

Apparent postnatal onset of some manifestations of the Wiedemann-Beckwith syndrome.

We report on 2 patients who were apparently normal at birth but later developed characteristics of Wiedemann-Beckwith syndrome (WBS). Both had hypoglycemia neonatally and gradually developed coarse facial changes, umbilical hernia, and macroglossia. Renal sonography done after the macroglossia developed showed large kidneys in both. The placentas were carefully examined in both cases but findings described as typical of WBS were only found in one. The clinical evolution of these infants suggests that some WBS manifestations may have their onset postnatally in some cases. We postulate that the cellular hyperplasia and hypertrophy characteristic of WBS may be caused by persistent rests of embryonal cells that secrete paracrine and/or endocrine growth factors.

Beckwith-Wiedemann Syndrome↗
PubMed1989

Neonatal autoimmune thrombocytopenia: role of high-dose intravenous immunoglobulin G therapy.

High-dose intravenous immunoglobulin G (IVIgG) therapy results in a rapid reversal of thrombocytopenia in over 80% of children with acute immune thrombocytopenic purpura (ITP). Comparable results were observed in eleven infants with an analogous condition, neonatal autoimmune thrombocytopenia (NATP), who received IVIgG (2 g/kg body weight) administered alone (n = 6) or in combination with steroids (n = 5). The median platelet count pre-IVIgG therapy was 25 X 10(9)/l (range 5 to 74 X 10(9)/l). The overall response rate to IVIgG therapy, administered alone or in combination with steroids was 75% (12 of 16 treatment episodes). A good response to therapy was defined as an increase in the platelet count to greater than or equal to 50 X 10(9)/l and at least twice the pre-treatment value at 48 h after completion of the IVIgG infusion. The rapid and generally excellent response to IVIgG therapy in infants with NATP suggests that this treatment approach should be considered as first-line therapy for severely thrombocytopenic infants with this self-limiting but potentially serious disorder.

Autoimmune Diseases↗
PubMed1988

Modulation of red cell band 4.1 function by cAMP-dependent kinase and protein kinase C phosphorylation.

Human erythrocyte protein 4.1 is phosphorylated in vivo by several protein kinases including protein kinase C and cAMP-dependent kinase. We have used cAMP-dependent kinase purified from red cells and protein kinase C purified from brain to test the effects of phosphorylation on band 4.1 function. In solution, each kinase catalyzed the incorporation of 1-4 mol of PO4/mol of band 4.1. Phosphorylation of band 4.1 by each kinase resulted in a significant (50-80%) reduction in the ability of band 4.1 to promote spectrin binding to F-actin. Direct measurement of spectrin-band 4.1 binding showed that phosphorylation by each kinase also caused dramatic reduction in this association. Phosphorylation of band 4.1 by each kinase for increasing time periods enabled us to demonstrate an approximately linear inverse relationship between PO4 incorporation into band 4.1 and spectrin binding. These results show that phosphorylation of band 4.1 by cAMP-dependent kinase and protein kinase C may be central to the regulation of red cell cytoskeletal organization and membrane mechanical properties.

Animals↗
PubMed1988

Effects of different thyroid treatments on the biochemical characteristics of rabbit myocardium.

It is well established that extreme dysthyroidism drastically alters the biochemical character of cardiac muscle. The purpose of this study was to determine if minor thyroid treatments would result in significant changes in the character of three major biochemical systems of muscle: metabolic; calcium regulating; and contractile systems. Different groups of New Zealand white rabbits had continuous time release propylthiouracil (PTU) pellets (500, 300, 200 and 100 mg) or triiodothyronine (T3) pellets (15 and 25 mg) subcutaneously implanted for 21 days. The ventricular myosin phenotypes shifted from 92% V3 myosin in the control rabbit hearts to 55% V3 and 10% V3 in the 15 mg and 25 mg T3 groups, respectively. PTU treatment resulted in a complete shift to the V3 myosin isoform. The sarcoplasmic reticulum Ca2+-ATPase activity increased with T3 and decreased with PTU treatments, except in the 500 mg PTU group. Ca2+-ATPase activity in the groups either side of the euthyroid group (100 mg PTU and 15 mg T3) did not change significantly. The glycolytic or aerobic potentials of the myocardium did not change with any of these minor thyroid treatments. It was concluded that the metabolic, enzymes, sarcoplasmic reticulum Ca2+-ATPase and myosin isozymes have different sensitivities to thyroid treatment and that minor thyroid treatments do result in significant changes in the biochemical character of the myocardium. These findings indicate that subclinical deviations in euthyroid status may affect myocardial biochemical character.

Animals↗
PubMed1987

Chromogranin A-like proteins in the secretory granules of a protozoan, Paramecium tetraurelia.

The ciliate protozoan Paramecium tetraurelia produces secretory granules (trichocysts) which release needle-like structures composed of small, acidic proteins. Using antibodies against isolated chromogranin A (CGA) and against trichocyst proteins, we found cross-reactive proteins in chromaffin granules and trichocysts. Four independently derived sera against isolated CGA stained bands of the Mr 15,000-25,000 family of trichocyst proteins on immunoblots. A positive response was also obtained with antiserum against chemically synthesized peptides (PL26 and GE25) corresponding to defined regions of the CGA amino acid sequence. In extracts of whole Paramecium, larger proteins (Mr 53,000 and 49,000) also reacted with antibodies against CGA and the related synthetic peptides. These larger proteins may represent unprocessed precursors to the smaller proteins of mature trichocysts. Antiserum to trichocysts recognized CGA in chromaffin granule lysates. Further evidence of a Paramecium protein related to CGA was provided by hybridization of Paramecium mRNA with cloned cDNA for bovine CGA. Our results suggest striking conservation in evolution of CGA-like proteins that may play some role, as yet unknown, in secretion.

Animals↗
PubMed1987

Nearest neighbor analysis for brain synapsin I. Evidence from in vitro reassociation assays for association with membrane protein(s) and the Mr = 68,000 neurofilament subunit.

Synapsin I, a major neuron-specific substrate for cAMP-dependent and Ca2+/calmodulin-dependent protein kinases, associates in in vitro assays with brain integral membrane protein site(s) distinct from secretory vesicles and with the neurofilament Mr = 68,000 subunit. The membrane sites for synapsin involve protein(s) and are likely to have physiological relevance since the binding of 125I-labeled synapsin is abolished by digestion with chymotrypsin, is displaced by unlabeled synapsin, is of high affinity (KD = 10 nM), and has a capacity (42 pmol/mg membrane protein) that is comparable to the amount of synapsin in brain, optimal binding occurs at physiological pH (6.8-7.2) and salt concentrations (50 mM), and synapsin binding to membranes is inhibited by phosphorylation with Ca2+/calmodulin-dependent protein kinase. The brain membrane protein sites for synapsin are not due to synaptic vesicles, since synaptic vesicles do not sediment under the conditions of the binding assay. Association between synapsin and the Mr = 68,000 neurofilament subunit has also been demonstrated. The binding of synapsin with the neurofilament subunit is specific since this binding interaction is saturable, with a 1:1 stoichiometry, the binding involves only certain proteolytically derived domains of synapsin, and is therefore not a simple electrostatic interaction between the basic domains of synapsin and the acidic regions in the neurofilament subunit, and Ca2+/calmodulin-dependent phosphorylation of synapsin inhibits this interaction. Synapsin promotes cross-linking of synaptic vesicles to brain membranes, and these complexes are reduced by phosphorylation of synapsin. This interconnecting function of synapsin may be a general characteristic of synapsin binding, with a membrane (synaptic vesicle or nonsecretory vesicle)-bound synapsin associating with microtubules, neurofilaments, or spectrin.

Animals↗
PubMed1987

Oral vitamin E supplementation for the prevention of anemia in premature infants: a controlled trial.

Serum vitamin E levels are reduced in newborn infants. It has been reported that this deficiency is responsible, in part, for the development of anemia in premature infants during the first 6 weeks of life. The efficacy of vitamin E supplementation for the prevention of anemia in premature infants has been studied in a randomized, controlled, and blinded trial. Premature infants whose birth weights were less than 1,500 g were given, by gavage, 25 IU of dl-alpha-tocopherol or a similar volume of the drug vehicle. Treatment was continued for the first 6 weeks of life. A total of 178 infants were studied. Vitamin E levels were significantly higher in a supplemented group by day 3 and for the remainder of the 6-week period. At 6 weeks of age, there was no significant difference between the supplemented and unsupplemented groups in hemoglobin concentration, reticulocyte and platelet counts, or erythrocyte morphology. It is concluded that there is no evidence to support a policy of administering vitamin E to premature infants to prevent the anemia of prematurity.

Anemia, Neonatal↗
PubMed1986

Protein kinase C phosphorylates a recently identified membrane skeleton-associated calmodulin-binding protein in human erythrocytes.

A membrane skeleton-associated protein with calmodulin-binding activity recently has been purified and characterized from human erythrocytes (Gardner, K. and Bennett, V. (1986) J. Biol. Chem. 261, 1339-1348). This new protein (CaM-BP103/97) has now been identified as a major substrate for protein kinase C in erythrocytes since phosphorylation of both of its subunits (Mr = 103,000 and 97,000) is elevated 3-15-fold in the presence of the phorbol ester, 12-O-tetradecanoylphorbol beta-acetate (TPA), under the following conditions: ghost membranes incubated with protein kinase C purified from rat brain, ghost membranes from erythrocytes pretreated with TPA, and intact erythrocytes metabolically labeled with 32PO4 and stimulated by TPA. The sites of phosphorylation of this protein by exogenous and endogenous protein kinase C are identical since two-dimensional 32P-peptide maps of both subunits labeled by either endogenous or exogenous enzyme are indistinguishable. Each subunit of CaM-BP103/97 accepts up to 3 mol of phosphate/polypeptide chain. In the presence of low calcium concentrations and in the absence of cytosol, the phosphorylation of CaM-BP103/97 is, on a molar basis, equal to or greater than that of proteins 4.1 and 4.9. As a target for both calmodulin and protein kinase C, CaM-BP103/97 is likely to play a key role in the effect of calcium on erythrocyte membrane shape and stability.

Adenosine Triphosphate↗
PubMed1984

Phorbol ester stimulates the phosphorylation of rabbit erythrocyte band 4.1.

The effect of phorbol esters on membrane phosphorylation was examined in intact rabbit erythrocytes prelabeled with [32P]orthophosphate. Tumor-promoting phorbol ester, phorbol 12-myristate 13-acetate, but not the inactive 4 alpha-phorbol 12,13-didecanoate, specifically stimulated the phosphorylation of two proteins in the erythrocyte membrane. They have apparent molecular weight of 100,000 dalton and 85,000 dalton. When intracellular calcium concentrations were raised by ionomycin, A23187, both the 85,000 dalton polypeptide and the 85K phosphoprotein were degraded. The 85,000 dalton phosphoprotein showed cross-reactivity with antiserum to human erythrocyte band 4.1. Based on its susceptibility to calcium-activated protease and its immunological property, the 85,000 dalton phosphoprotein was identified to be the band 4.1 of the erythrocyte membrane skeletal network.

Animals↗
PubMed1982

Purification and characterization of an (Na+ + K+)-ATPase proteolipid labeled with a photoaffinity derivative of ouabain.

Highly purified lamb kidney (Na+ + K+)-ATPase was photoaffinity labeled with the tritiated 2-nitro-5-azidobenzoyl derivative of ouabain (NAB-ouabain). The labeled (Na+ + K+)-ATPase was mixed with unlabeled carrier enzyme. Two proteolipid (gamma 1 and gamma 2) fractions were then isolated by chromatography on columns of Sepharose CL-6B and Sephadex LH-60. The two fractions were interchangeable when rechromatographed on the LH-60 column, suggesting that gamma 1 is an aggregated form of gamma 2. The total yield was 0.8-1.5 mol of gamma component per mol of catalytic subunit recovered. This indicates that the gamma component is present in stoichiometric amounts in the Na+ + K+)-ATPase. The proteolipids that were labeled with NAB-ouabain copurified with the unlabeled proteolipids.

Amino Acids↗