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Biomedical subjects

E Kelly

Publications and source records attributed to E Kelly.

At least 19 recordsLinked to original sources
PubMed1992

Cloning of the gene coding for a human receptor for formyl peptides. Characterization of a promoter region and evidence for polymorphic expression.

Recently we reported that, in HL-60 cells, transcription of the formyl peptide receptor (FPR) gene can be up- and downregulated by agents that induce differentiation of HL-60 cells into neutrophils. To begin studying the mechanisms involved in regulation of FPR gene expression, we cloned two human cDNAs and the gene coding for FPR. The genomic clone (pINF14) contained a 14.5-kb insert. A 2.7-kb EcoRI fragment was obtained from pINF14 that hybridized with an FPR open reading frame probe. The EcoRI fragment was sequenced and found to contain an intronless FPR open reading frame. Sequence alignment of the EcoRI genomic fragment with the FPR cDNA revealed that the first 31 bases of 5' untranslated FPR cDNA were not represented in the genomic fragment. Furthermore, a splicing consensus sequence was present in the genomic fragment at the site of divergence with the cDNA sequence. Restriction mapping and Southern blot analysis identified a 121-bp fragment that contained the sequence corresponding to the first 31 bases of 5' untranslated FPR cDNA. An additional (previously undescribed) 15-bp cDNA sequence in the 5' end of FPR were identified using an anchored polymerase chain reaction. This sequence was also contained in the genomic 121-bp fragment. This 121-bp fragment was located 5.2 kb (intron) upstream of the FPR open reading frame. It contained an unusual TATA box and displayed transcriptional activity in vitro and in vivo. Potential binding sites for AP-1 and glucocorticoid receptor were identified upstream of the putative TATA box.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1992

Cloning of a cDNA encoding a receptor related to the formyl peptide receptor of human neutrophils.

We cloned a cDNA (RFP) encoding a receptor (RFP) related (70% overall nucleotide homology) to the formyl peptide receptor of human neutrophils (hFPR). RFP is a seven-transmembrane-domain receptor and its distribution is limited to myeloid cells. Domain sequence comparison with hFPR reveals highly conserved regions and provides clues to putative domains involved in ligand binding and receptor desensitization.

Amino Acid Sequence↗
PubMed1992

Cyclic AMP produces desensitization of prostacyclin and adenosine A2 receptors in hybrid cell lines but does not affect Gs function.

Prostacyclin and adenosine A2 receptors stimulate adenylate cyclase activity in the related somatic hybrid cell lines NG108-15 and NCB20. The role of cAMP in the desensitization of these receptors has been examined. Pretreatment for 17 h with forskolin or 8-bromo-cAMP had the same effect in both cell lines. There was no change in the response to sodium fluoride or forskolin, suggesting that the function of Gs and adenylate cyclase were unaffected by increased levels of cAMP. Receptor responses were affected however; the maximum response to N-ethylcarboxamidoadenosine (an A2 receptor agonist) was reduced by 30-40%, there was a small but consistent shift to the right of the dose-response curve for iloprost (a stable analogue of prostacyclin) and [3H]iloprost binding studies revealed a loss of prostacyclin receptors. However, the loss of receptor responsiveness was much smaller than that which occurs following pretreatment with prostacyclin or adenosine A2 receptor agonists (Keen et al. (1989) Biochem. Pharmacol. 38, 3827-3833; Kelly et al. (1990) Br. J. Pharmacol. 99, 309-316) suggesting that cAMP may not play a major role in agonist mediated desensitization.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1992

Regulation of formyl peptide receptor expression and its mRNA levels during differentiation of HL-60 cells.

When incubated with N6-2'-O-dibutyryladenosine 3',5'-cyclic monophosphate (dbcAMP), HL-60 cells expressed formyl peptide receptor (FPR) (as assessed by ligand binding) and FPR transcripts in a time- and concentration-dependent fashion. Experiments using dbcAMP analogs modified at either the C-6 or C-8 position indicated that the process was mediated by a protein kinase A type I, and protein kinase A type I activity was isolated from undifferentiated HL-60 cells by DEAE-Sephacel chromatography. Forskolin mimicked the effects of dbcAMP. Forskolin and dbcAMP-dependent expression of FPR and FPR transcript was inhibited by staurosporine. Retinoic acid (but not retinal or retinol) was capable of inhibiting dbcAMP-dependent expression of FPR mRNA half-life. Dexamethasone enhanced the effects of dbcAMP and blocked the inhibitory effect of retinoic acid on expression of FPR and FPR transcripts. Phorbol 12-myristate 13-acetate (PMA) alone (1.5-15 nM) failed to induce HL-60 to express FPR and FPR transcripts. Low concentrations (1.5 nM) of PMA enhanced the ability of dbcAMP to induce HL-60 cells to express FPR and FPR transcript, whereas high (15 nM) concentrations of PMA inhibited dbcAMP effects. These results indicate that expression of FPR and FPR transcripts by HL-60 cells can be up- and down-regulated by agents that induce HL-60 cells to differentiate and that a "cross-talk" effect exists between protein kinase A and protein kinase C that modulates FPR gene transcription (and receptor expression) by these cells.

Alkaloids↗
PubMed1992

Very low birth weight and growth to age 8 years. II: Head dimensions and intelligence.

The occipitofrontal circumference was measured in all available children in the following cohorts at ages 2, 5, and 8 years: group 1, consisting of 79 children with birth weight between 500 and 999 g; group 2, with 111 children with birth weight between 1000 and 1499 g; and group 3 with 56 children with birth weight greater than 2500 g; all were white with no signs of moderate or severe cerebral palsy. National Center for Health Statistics reference values indicated substantially more children with an occipitofrontal circumference lower than the 10th percentile, particularly at age 2 years, compared with Nellhaus reference data. Occipitofrontal circumference was the head measurement best correlated with the Full Scale IQ on the Wechsler Intelligence Scale for Children-Revised. Dolichocephaly, often seen in very-low-birth-weight children was unrelated to IQ, and correction of occipitofrontal circumference for dolichocephaly was rarely of clinical importance.

Analysis of Variance↗
PubMed1992

Prospective study of the quality of survival of infants with critical fetal reserve detected by antenatal cardiotocography.

From 1981 to 1986 antenatal cardiotocographic monitoring was performed on 9,992 high-risk pregnancies selected from a total obstetrical population of 31,518 patients (31.7%). A critical fetal reserve pattern was detected in 89 patients (0.9%) whose pregnancies resulted in 68 surviving infants, 19 perinatal deaths and 2 sudden infant deaths. Since 47.4% of the infants who died in the perinatal period did so because of a related congenital malformation, such a defect should be excluded in the fetus with critical fetal reserve, by ultrasonography, before delivery (there is usually insufficient time for fetal karyotyping). Sixty-three (92.6%) of the surviving children were assessed at our Growth and Developmental Clinic and disabilities were detected in 16 (25.4%); however, the disability was major in only 5, including 2 children with Down syndrome. The quality of survival of infants born from pregnancies complicated by critical fetal reserve was satisfactory as 60 of 63 children (95.2%) had neither a major disability related to intrauterine hypoxia identified by the cardiotocographic pattern, or had one likely to significantly interfere with their quality of life. Our results suggest that pregnancies can be continued until the cardiotocographic pattern becomes critical in order to gain fetal maturity, without compromise to the fetal brain.

Cardiotocography↗
PubMed1991

Guanine nucleotide sensitivity of [3H]iloprost binding to prostacyclin receptors.

A component of the displaceable binding of the stable prostacyclin analogue, [3H]iloprost, to membranes from human platelets and the somatic hybrid cell lines NG108-15 and NCB20, was inhibited by guanine nucleotides. The order of potency of a range of nucleotides for this effect was GTP gamma S greater than GppNHp greater than GTP greater than GDP = GMP; ATP, UTP and CTP were ineffective at concentrations up to 1 mM. In the presence of 100 microM GppNHp, iloprost binding curves were displaced to the right of curves obtained in the absence of guanine nucleotide, and their Hill slopes were greater. This was consistent with a conversion of a minor population of high affinity agonist binding sites to lower affinity sites in the presence of guanine nucleotides. These effects of guanine nucleotides on the binding of the agonist ligand [3H]iloprost were consistent with an interaction with a G protein coupled receptor.

Cell Membrane↗
PubMed1991

Changing two-year outcome of infants weighing 500 to 999 grams at birth: a hospital study.

Survival and neurodevelopmental outcome to 2 years were determined for two cohorts of infants weighing 500 to 999 gm at birth, born in a tertiary maternity hospital. Live births increased over time from an annual average of 48.7 in the first era (January 1977 to March 1982) to 64.6 in the second era (January 1985 to December 1987), largely from referrals of additional mothers with pregnancy complications. In the first era, 33.6% (86/256) of infants survived to 2 years; the survival rate improved significantly to 45.9% (89/194) in era 2. After adjustment for birth weight, the odds ratio for survival in era 2 versus era 1 was 1.39 (95% confidence interval = 1.12, 1.73; p less than 0.01). One known survivor in each era was not seen at 2 years of age. In the first era, 59.3% (51/86) of 2-year-old children were free of disability compared with 68.5% (61/89) in era 2 (NS), but the Mental Development Index of the Bayley Scales improved significantly, from 90.0 in era 1 to 98.0 in era 2. For infants weighing less than 800 gm at birth, not only did the 2-year survival rate improve, adjusted for birth weight (odds ratio = 1.53; 95% confidence interval = 1.06, 2.20; p less than 0.05), but there was also a significant reduction in neurologic disabilities in survivors (p = 0.03). For infants weighing 800 to 999 gm at birth, there was a significant improvement in the survival rate, adjusted for birth weight (odds ratio = 1.37; 95% confidence interval = 1.04, 1.79; p less than 0.05), but the rate of neurologic disabilities was unchanged. Increased survival in our tertiary maternity center was achieved without increasing the annual number of severely disabled 2-year-old survivors.

Child, Preschool↗
PubMed1991

Octimibate, a potent non-prostanoid inhibitor of platelet aggregation, acts via the prostacyclin receptor.

1. Octimibate, 8-[(1,4,5-triphenyl-1H-imidazol-2-yl)oxy]octanoic acid, is reported to have antithrombotic properties. This is in addition to its antihyperlipidaemic effects which are due to inhibition of acylCoA:cholesterol acyltransferase (ACAT). The aim of this study was to investigate the mechanism of the antithrombotic effect of octimibate, and to determine whether the effects of octimibate are mediated through prostacyclin receptors. 2. In suspensions of washed (plasma-free) human platelets, octimibate is a potent inhibitor of aggregation; its IC50 is approx. 10 nM for inhibition of aggregation stimulated by several different agonists, including U46619 and ADP. The inhibitory effects of octimibate on aggregation are not competitive with the stimulatory agonist; the maximal response is suppressed but there is no obvious shift in potency of the agonist. In platelet-rich plasma, octimibate inhibits agonist-stimulated aggregation with an IC50 of approx. 200 nM. 3. Octimibate also inhibits agonist-stimulated rises in the cytosolic free calcium concentration, [Ca2+]i, in platelets. Both Ca2+ influx and release from intracellular stores are inhibited. The effects of octimibate on aggregation and [Ca2+]i are typical of agents that act via elevation of adenosine 3':5'-cyclic monophosphate (cyclic AMP). Similar effects are seen with forskolin, prostacyclin (PGl2) and iloprost (a stable PGl2 mimetic). 4. Octimibate increases cyclic AMP concentrations in platelets and increases the cyclic AMP-dependent protein kinase activity ratio. Octimibate stimulates adenylyl cyclase activity in human platelet membranes, with an EC50 of 200 nM. The maximal achievable activation of adenylyl cyclase by octimibate is 60% of that obtainable with iloprost. Octimibate has no effect on the cyclic GMP-inhibited phosphodiesterase (phosphodiesterase-ITI), which is the major cyclic AMP-degrading enzyme in human platelets.5. Octimibate inhibits, apparently competitively, the binding of [3H]-iloprost (a stable PGl2 mimetic) to platelet membranes; the estimated Ki is 150 nm. 6. The platelets of different species show considerable differences in the apparent potency of their inhibition of aggregation by octimibate; platelets from cynomolgus monkeys are 3 fold more sensitive than those from humans, while rat, cat and cow platelets are 50, 100, and 250 fold less sensitive than human platelets. The sensitivity of these different species to iloprost, however, varies over a range of only 10 fold with no obvious difference between primates and non-primates. 7. Octimibate appears to be a potent agonist (aggregation), or partial agonist (adenylyl cyclase), at prostacyclin receptors and is the first non-prostanoid agent of this type to be identified. The species differences in relative potency of octimibate and iloprost may reflect the existence of receptor subtypes.

Adenylyl Cyclases↗
PubMed1991

Second twin: quality of survival if born by breech extraction following internal podalic version.

The intrapartum management of the vertex-breech and vertex-transverse twin gestation is controversial. The fall in perinatal mortality rate to a low level has resulted in this parameter failing to be an adequate gauge of the safety of breech extraction and the answer lies in the quality of survival of the infants. Fifty-one twin pairs, collected over 12 years at the Mercy Hospital for Women, Melbourne, occurred where twin 2 was born by breech extraction following internal inversion and the control (twin 1) did not have this procedure performed. In 8 pairs either a stillbirth or neonatal death occurred; in one pair childhood death due to an accident (fire) occurred; in 4 pairs the parents refused entrance to the study as they perceived both twins to be similar; in 2 sets the assessment was incomplete; 11 sets were untraceable leaving 25 sets fully assessed as children ranging in age from 2 to 12 years. Growth, and psychological scores were not significantly different between twins 1 and 2 but 2 children had cerebral palsy and both were born by breech extraction following internal version at 29.2 and 30.1 weeks' gestation, respectively. Because of small numbers the results failed to achieve statistical significance and this study was unable to answer the question regarding the safety of breech extraction following internal version but did show that the majority of infants so born do well.

Apgar Score↗
PubMed1991

Survivors of extreme prematurity--outcome at 8 years of age.

Of 149 infants liveborn in a large maternity hospital in 1980 to 1982 and delivered between 24 and 29 completed weeks of gestation inclusive, 91 (61%) survived; 88 (97%) survivors were assessed at 8 years' corrected age; 77% of children were not disabled; disability was mild in 13%, moderate in 2% and severe in 4% of children. Although survival decreased with decreasing gestation, disability in survivors did not increase. An earlier assessment of the same children at approximately 2 years of age had been unduly pessimistic particularly for those born less than or equal to 26 weeks' gestation. The only other reports in the literature on outcome by gestation have all assessed the children in early childhood, and estimates of severe disability rates from these studies will probably also be too pessimistic. Since the rate of severe disabilities in infants of borderline viability is not much higher than in more mature infants the obstetrician should mainly consider survival chances for the fetus, and not be overly concerned with long-term neurological outcome, when making clinical decisions.

Australia↗
PubMed1991

Effect of in vitro preconditioning on tracheal smooth muscle responsiveness.

We evaluated the effect of preconditioning of the isometric contractile response of canine tracheal smooth muscle (TSM) in vitro. Strips of epithelium-free TSM (n = 90) were excised from 16 anesthetized dogs and fixed isometrically in tissue perfusion chambers. Experiments were performed using methods previously reported in which the following parameters were investigated: 1) quiescent equilibration time in the perfusion chamber (0-120 min); 2) effect of repeated exchange of perfusate; 3) method of determining the optimal resting length (Lmax) for presetting of resting tension (RT); 4) effect of precontraction during the equilibration phase on the contractile response to agonists administered subsequently; and 5) method of determining RT on the response to muscarinic stimulation. When other variables were uniform, neither equilibration time nor perfusate exchange affected potency or efficacy of the response generated subsequently to acetylcholine (ACh). However, both potency (range of EC50: -5.71 +/- 0.14 log M to -6.52 +/- 0.24 log M; P less than 0.02) and efficacy (range of maximal active tension: 1,143 +/- 268 g/cm2 to 2,878 +/- 151 g/cm2; P less than 0.001) of ACh were altered substantially as a result of the method used to estimate Lmax. Repeated precontraction by electrical field stimulation or with 127 mM KCl did not alter potency or efficacy of contraction elicited by ACh. Maximal active tension generated with 10(-3) M ACh was 2,878 +/- 151 g/cm2 after 12-15 tetanizing field stimulations and 2,696 +/- 198 g/cm2 after 5-7 contractions with 127 mM KCl (P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1991

Extracellular Ca2+ mobilization in potential-dependent contraction of trachealis of maturing swine.

We studied the effect of maturation on potassium-induced parasympathetic activation and Ca2+ entry in tracheal smooth muscle (TSM) from fifteen 2-wk-old (2ws) and sixteen 10-wk-old (10ws) male domestic farm swine. Atropine (10(-7) M) caused inhibition of the maximal contraction elicited by potassium to 50.3 +/- 2.6% maximum of control response (P less than 0.001) in TSM from 2ws but had no significant effect in TSM from 10ws (94.6 +/- 4.2% maximum; P = NS vs. control). Verapamil (10(-7) M) plus 10(-7) M atropine reduced contraction elicited by potassium in both 2ws (23.7 +/- 5.8% maximum; P less than 0.001 vs. control) and 10ws (50.6 +/- 6.3% maximum; P less than 0.001 vs. control, P less than 0.05 vs. 2ws); 10(-6)M verapamil caused greater than 95% blockade of contraction caused by potassium in both 2ws and 10ws. In separate studies, atropine-treated strips were equilibrated with extracellular Ca2+ concentrations ([Ca2+]o) ranging from normal (1X [Ca2+]o) to four times normal (4x [Ca2+]o). Increasing [Ca2+]o increased maximal contractile response in atropine-treated TSM strips from 68.7 +/- 3.8% maximum for 1x [Ca2+]o to 100.8 +/- 4.8% maximum for 4x [Ca2+]o (P less than 0.001) in 2ws. Neither atropine nor [Ca2+]o affected maximal responses of TSM in 10ws (103.5 +/- 3.0% maximum for 1x [Ca2+]o; P = NS vs. control). However, in the presence of atropine and verapamil, 4x [Ca2+]o augmented KCl-elicited contraction of TSM from both 2ws (46.9 +/- 6.3% maximum; P less than 0.01 vs. control) and 10ws (78.6 +/- 2.3% maximum; P less than 0.005 vs. control).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Reduced activity of acetylcholinesterase in canine tracheal smooth muscle homogenates after active immune-sensitization.

Previous investigations have suggested that immune-sensitization increases airway smooth muscle responsiveness to cholinomimetic stimulation by reducing the rate of degradation of acetylcholine. To examine the hypothesis that increased cholinomimetic responsiveness of tracheal smooth muscle (TSM) caused by immune-sensitization results from inhibition of acetylcholinesterase (AChase) activity, we developed a method for direct measurement of AChase activity in homogenates of TSM obtained from mongrel dogs actively sensitized in vivo to ragweed pollen extract (n = 7) and sham-sensitized littermate controls (n = 7). For both sensitized and control specimens, saturation of AChase was obtained at approximately 3.12 mM substrate (acetylthiocholine); however, maximal enzyme activity in homogenates of ragweed-sensitized tissues was significantly less (0.862 +/- 0.088 absorbance units/min/mg protein [AU/min/mg]) compared to control homogenates (1.590 +/- 0.129 AU/min/mg; P less than 0.001). Kinetic analysis (Eadie-Hofstee plot) indicated similar Michaelis constants (Km) for AChase from ragweed-sensitized (0.360 +/- 0.063) and control (0.336 +/- 0.062) homogenates (P = NS). The concentration of physostigmine eliciting half-maximal inhibition (Ki) of AChase activity also was similar for tissues from sensitized (-7.92 +/- 0.032 log M) and control animals (-7.86 +/- 0.012 log M; P = NS). Pretreatment with selected mediators of anaphylaxis (10(-4) M histamine, 10(-6) M serotonin, 10(-5) M prostaglandin E2, 10(-6) M prostaglandin F2 alpha, and 10(-7) M leukotriene D4) did not affect AChase activity. Our data demonstrate reduced AChase activity in homogenates of canine TSM after active immune-sensitization in vivo. This corresponds to functional augmentation of cholinomimetic contraction in actively sensitized tissues.

Acetylcholinesterase↗
PubMed1991

Defective polymorphonuclear leukocyte formyl peptide receptor(s) in juvenile periodontitis.

Juvenile periodontitis (JP) is a disease characterized by severe gingival infections. PMN from some JP patients exhibit abnormal chemotactic responsiveness when challenged with the synthetic formyl peptide, FMLP. While investigating PMN function in JP, we found a patient in whom abnormal PMN chemotactic responses to FMLP were associated with a defective population of PMN formyl peptide receptor(s) (FPR). JP PMN failed to respond chemotactically when challenged with FMLP, but exhibited normal chemotactic responses upon exposure to purified human C5a. Furthermore, JP PMN were capable of degranulating and generating superoxide anion radicals as well as normal PMN upon exposure to FMLP. Binding studies demonstrated that JP PMN had a diminution in the number of high-affinity FPR. Studies in which FPR was radiolabeled by chemical cross-linking demonstrated that JP PMN FPR exhibited the same molecular weight and N-linked glycosylation as normal PMN FPR. JP PMN FPR, however, was more resistant to papain cleavage than normal PMN FPR. Autoradiograms obtained from 2D-PAGE of normal and JP PMN FPR demonstrated decreased amounts of FPR isoforms in JP PMN.

Adult↗
PubMed1990

Effect of phorbol myristate acetate on processing of formyl peptide receptors by human neutrophils.

We examined the effect of phorbol myristate acetate on the ability of human neutrophils to process formyl peptide receptors. The receptor was affinity-labeled and its extracellular localization assessed over time, by cleavage of extracellular labeled receptor with papain. Neutrophils were capable of internalizing (and/or recycling) affinity labeled formyl peptide receptor in the absence of extracellular calcium. This phenomenon was dependent upon stimulation with phorbol myristate acetate, suggesting a role for protein kinase C in this process.

Binding, Competitive↗
PubMed1990

Bladder volume determination using a dedicated, portable ultrasound scanner.

Urethral catheterization, the standard method for measurement of bladder volume, is associated with patient discomfort plus the risks of urethral trauma and urinary tract infection. A portable ultrasound instrument that automatically determines bladder volume was used for 164 determinations and the digital readout correlated with the catheterized volume (r2 equals 0.79). This instrument is a noninvasive alternative to urethral catheterization for the determination of bladder volume in most patients.

Evaluation Studies as Topic↗