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Biomedical subjects

J A Manning

Publications and source records attributed to J A Manning.

At least 19 recordsLinked to original sources
PubMed2001

Pharmacodynamics and pharmacokinetics of omapatrilat in heart failure.

The purpose of this study was to determine the pharmacodynamics and pharmacokinetics of omapatrilat, administered orally (25 mg) or intravenously (10 mg) in 19 New York Heart Association class II and class III congestive heart failure (CHF) patients versus 17 healthy controls matched for age, race, gender, and weight. The plasma concentrations of atrial natriuretic peptide (ANP) increased by approximately 20% and 30% in CHF and control subjects, respectively, at 4 hours after intravenous or oral omapatrilat administration. Similar elevation in the cyclic guanosine monophosphate concentration (25% to 35%) and ANP urinary excretion (21 ng/24 h to 22 ng/24 h) was seen in all treatment groups after omapatrilat administration. Angiotensin-converting enzyme activity was > 90% inhibited at 4 hours after dosing and remained approximately 60% to 70% inhibited at 24 hours after dosing. The levels of endothelin-1 and endothelin-2 remained unchanged after oral or intravenous administration of omapatrilat. The maximal reduction in seated blood pressure compared with baseline was similarfor CHF and control subjects. Clinical pharmacokinetic parameters were similar in both groups after intravenous dosing, but maximum concentration and area under the concentration-time curve were elevated in CHF patients compared with controls after oral dosing. Omapatrilat was well tolerated; differences in systemic exposure and metabolism between CHF patients and controls did not appear to be clinically significant.

Administration, Oral↗
PubMed2000

Safety and pharmacokinetics of a single oral dose of gatifloxacin in patients with moderate to severe hepatic impairment.

STUDY OBJECTIVES: To assess the safety and pharmacokinetics of oral gatifloxacin 400 mg in subjects with and without hepatic impairment, and the need to modify doses in patients with hepatic dysfunction. DESIGN: Single-dose, nonrandomized, open-label, parallel-group study. SETTING: Clinical Research Center, New Orleans, Louisiana. PATIENTS: Eight subjects with grade B or C hepatic dysfunction (Child-Pugh classification) and eight age-, weight-, and gender-matched subjects with normal hepatic function. INTERVENTIONS: After a single oral dose of gatifloxacin 400 mg, blood and urine samples were collected at specified times or intervals over 48 hours to determine drug concentrations. MEASUREMENTS AND MAIN RESULTS: All 16 subjects (7 with grade B and 1 with grade C hepatic impairment, 8 with normal hepatic function) completed the study. Peak plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC0-infinity) for gatifloxacin were 32% and 22% higher, respectively, in subjects with hepatic impairment. Except for Cmax, the ratio of means for AUC satisfied the specified criterion (0.67-1.50) for lack of effect. There were no statistically significant differences in any other pharmacokinetic values except apparent oral clearance (ClT/F). All treatment-emergent adverse events were mild or moderate in intensity and resolved before subjects were discharged from the study. CONCLUSION: Modest increases in Cmax and AUC0-infinity are not anticipated to have a negative effect on the outcome of therapy in hepatically impaired subjects, nor are they anticipated to result in adverse drug reactions. Patients with moderate to severe (Child-Pugh grade B or C) hepatic dysfunction do not require gatifloxacin dose adjustments. In addition, the similarity in half-life (t1/2) for the groups (8.9 hrs for hepatically impaired subjects, 9.3 hrs for controls) suggests that no difference would be anticipated in the extent of drug accumulation after multiple doses. The overall safety and tolerability of a single oral dose of gatifloxacin 400 mg were excellent in both healthy subjects and those with hepatic impairment.

Adult↗
PubMed1995

High level expression and refolding of mouse interleukin 4 synthesized in Escherichia coli.

Mouse Interleukin 4 is a 20-kDa glycoprotein, synthesized by activated T lymphocytes and mast cells, which regulates the growth and/or differentiation of a broad spectrum of target cells of the immune system, including B and T lymphocytes, macrophages, and hematopoietic progenitor cells. Using an inducible recA promoter and the g10-L ribosome-binding site, recombinant non-glycosylated interleukin 4 (IL-4) was expressed as 17% of total cellular protein in Escherichia coli inclusion bodies, as a reduced, inactive 14.5-kDa polypeptide. The protein was refolded and aggregates dissociated when three disulfide bonds were reformed by slowly decreasing the concentration of guanidine hydrochloride and cysteine. The oxidized monomer was purified to homogeneity by sequential ion-exchange and size exclusion chromatography. When compared with native IL-4, E. coli-derived IL-4 displayed an identical specific activity of 4-7 x 10(7) units/mg. This recombinant IL-4 contained a three-amino-acid NH2-terminal extension, which did not affect its biological activity. Purified biologically active protein consisted of three isoforms as shown by two-dimensional gel electrophoresis, with a pI greater than 9.0. These data suggest that neither glycosylation nor the NH2 terminus of mouse IL-4 play a critical role in contributing to its in vitro biological activity.

Amino Acid Sequence↗
PubMed1995

Delivery of nascent MHC class II-invariant chain complexes to lysosomal compartments and proteolysis of invariant chain by cysteine proteases precedes peptide binding in B-lymphoblastoid cells.

The intracellular trafficking, proteolysis, and dissociation of invariant chain (li) associated with nascent class II molecules was examined in B-lymphoblastoid cells. Metabolic labeling and Percoll gradient centrifugation was used to assess the kinetics of delivery and processing of class II-li complexes within the endocytic pathway. Catabolism of class II-li complexes rapidly followed their delivery from post-Golgi compartments to dense lysosome-like compartments distinct from early and late endosomes. Direct peptide binding assays revealed that class II molecules associated with even small N-terminal fragments of li failed to bind peptide. Cysteine protease inhibitors alone blocked li proteolysis/dissociation and accumulation of class II-li biosynthetic intermediates within lysosome-containing compartments. Active-site labeling of cysteine proteases in B cells was used to identify cysteine proteases capable of mediating li proteolysis within endosomal compartments. Our results indicate rapid, possibly direct, transport of nascent class II-li complexes from the Golgi/trans-Golgi network to dense lysosomal compartments wherein cysteine protease(s), likely including cathepsin B, mediate complete removal of li. Inhibition of cysteine protease activity results in the accumulation of incompletely processed class II-li complexes, which lack peptide binding ability, within lysosomal compartments.

Amino Acid Sequence↗
PubMed1993

Medical therapy for the hydropic fetus with congenital complete atrioventricular block.

Early delivery, immediate ventricular pacing, and inotropic support have failed to improve the outcome of hydropic fetuses with congenital complete atrioventricular block. On detection of hydrops, two fetuses were treated with maternally administered digoxin and furosemide with prompt and sustained resolution of intrathoracic fluid accumulations. Clearance of serosal fluid collections may prevent pulmonary hypoplasia and improve cardiac function. Before proceeding with premature delivery in such patients, a brief trial of transplacental anti-congestive therapy is indicated.

Adult↗
PubMed1993

High-affinity fatty acid-binding activity in epidermis and cultured keratinocytes is attributable to high-molecular-weight and not low-molecular-weight fatty acid-binding proteins.

Fatty acid-binding proteins (FABPs) are abundant low-molecular-weight cytosolic proteins in tissues involved in fatty acid (FA) metabolism. Because epidermis is also an active lipogenic tissue, we examined cytosols from murine and porcine epidermis and cultured human keratinocytes and fibroblasts for FABPs. High-affinity FA-binding activity was present in both epidermis and differentiated keratinocytes, whereas no high-affinity FA-binding activity was found in cultured human fibroblasts or undifferentiated keratinocytes. By column chromatography, a single binding peak was identified in the high (90-100 kDa)-molecular-weight range and no binding activity was evident in the low (14-15 kDa)-molecular-weight range, where conventional FABPs elute. Moreover, rabbit anti-rat heart FABP, anti-rat intestine FABP, and anti-rat liver FABP antisera did not identify proteins in the 14-15-kDa range in murine epidermal cytosol by Western immunoblots, whereas the anti-rat-heart antibody recognized a protein of approximately 32 kDa. Isoelectric focusing of differentiated keratinocyte cytosol demonstrated a single FA-binding peak having a pI of approximately 4.0. Analysis of this binding peak by SDS-PAGE revealed peptides of approximately 66 and 38 kDa. These findings suggest the possibility that the FA-binding protein in keratinocyte cytosol normally exists as a heterodimer. Western immunoblots of both differentiated keratinocyte cytosol and keratinocyte-conditional media stained with a rabbit anti-human serum albumin antibody identified a protein of approximately 67 kDa, but the electrofocused fraction did not react with this antibody. Thus, epidermis and differentiated keratinocytes possess high-affinity cytosolic FA-binding activity that cannot be ascribed either to conventional low-molecular-weight FABPs or to albumin.

Binding, Competitive↗
PubMed1991

In situ binding of fatty acids to the liver fatty acid binding protein: analysis using 3-[125I]iodo-4-azido-N-hexadecylsalicylamide.

A photoactivatable radioiodinated fatty acid analogue, 3-[125I]iodo-4-azido-N-hexadecylsalicylamide (125I-AHS) has been synthesized and used to investigate the involvement of cellular lipid carriers in hepatic fatty acid utilization. Photoactivation of Hep G2 internalized 125I-AHS revealed that several cellular proteins were crosslinked with the radiolabeled fatty acid analogue. Three predominant proteins in the membrane fraction of the cell with molecular masses 17, 50 and 127 kDa were crosslinked with the lipid analogue, as determined using autoradiography after SDS-PAGE. Three other proteins in the soluble fraction of the cell, with molecular masses 14, 24 and 35 kDa, were also labeled in situ. In contrast to the other labeled proteins, the fatty acid analogue accumulated on the cytoplasmic 14 kDa protein in a time and temperature dependent fashion. The in situ-labeled 14 kDa protein was identified from primary rat hepatocytes as the liver fatty acid binding protein by partial purification and its ability to be immunoprecipitated with immunospecific L-FABP antiserum. Collectively the results indicate that fatty acids traverse the plasma membrane and are bound cytoplasmically by the liver fatty acid binding protein, as well as other proteins in the cell. This represents the first demonstration in intact hepatocytes that the liver fatty acid binding protein participates in the process of intracellular fatty acid trafficking, and supports a model in which cytoplasmic lipid carriers solubilize fatty acids as a step in their metabolic utilization.

Affinity Labels↗
PubMed1991

Isolation and characterization of fatty acid binding protein in the liver of the nurse shark, Ginglymostoma cirratum.

1. A 14.5 kDa fatty acid binding protein was isolated from the liver of the nurse shark, Ginglymostoma cirratum. 2. Purified shark liver FABP (pI = 5.4) bound oleic acid at a single site with an affinity similar to that of mammalian FABP. 3. The apparent size, pI and amino acid composition of shark liver FABP indicate a close structural relationship between this protein and mammalian heart FABP.

Animals↗
PubMed1990

The effects of indomethacin on renal function and intracranial hemorrhage in infants with patent ductus arteriosus.

The effects of indomethacin on patent ductus arteriosus (PDA) were retrospectively studied by evaluating 1,600 consecutive infants less than 36 weeks gestation from 1983 to 1986. Two hundred thirteen infants were diagnosed with a PDA, and 102 infants received indomethacin. Indomethacin was associated with successful PDA closure in 81 infants (79%), with 59 infants (58%) closing after a single dose. No cases of renal failure were observed after indomethacin. Nine infants were treated despite a creatinine (Cr) value greater than or equal to 1.5 mg/dl. Cr improved in all these infants after therapy. Blood urea nitrogen values were greater than or equal to 30 mg/dl in 22 infants at the time of treatment; 18 infants (82%) improved. An intracranial hemorrhage (ICH) was detected in 23 infants (22%) by cranial ultrasound prior to indomethacin; there was no progression after treatment. Data suggest that indomethacin is highly associated with closure of a PDA, and therapy did not result in prolonged renal dysfunction or worsening ICH.

Acute Kidney Injury↗
PubMed1989

Acinar heterogeneity of fatty acid binding protein expression in the livers of male, female and clofibrate-treated rats.

Liver fatty acid binding protein may play a role in the intracellular transport and compartmentation of long-chain fatty acid metabolism. The distribution of liver fatty acid binding protein in the hepatic acinus was determined by means of immunocytochemistry as well as by measurement of liver fatty acid binding protein in cellular protein selectively released from zone 1 and zone 3 cells by means of anterograde and retrograde liver perfusion with digitonin. In untreated male rats, specific immunocytochemical staining for liver fatty acid binding protein showed a declining portal-to-central hepatocellular gradient in intensity, consistent with the portal-to-central ratio of liver fatty acid binding protein abundance measured in effluents from digitonin-perfused livers of 1.6:1. Female and clofibrate-treated male rats, in both of which hepatic synthesis and abundance of liver fatty acid binding protein are greater than in untreated males, differed as well in the pattern of acinar expression of this protein. In females, periportal concentrations of liver fatty acid binding protein determined from the effluent of livers perfused anterograde with digitonin were similar to male values, whereas liver fatty acid binding protein concentration in pericentral hepatocytes determined from the effluent of retrograde perfused livers was increased, resulting in a marked attenuation of the portal-to-central gradient of this protein; this was also apparent on immunocytochemistry. Clofibrate-treated rats, in contrast, displayed a panacinar increase in liver fatty acid binding protein with maintenance of the portal-to-central ratio observed in untreated males. We conclude that there exists a declining portal-to-central gradient in liver fatty acid binding protein cellular abundance in the hepatic acinus of untreated male rats. Furthermore, the increased synthesis and abundance of liver fatty acid binding protein in female and clofibrate-treated male rats results in two different alterations in the acinar expression of this protein, i.e. a pericentral increase (female) or a panlobular increase (clofibrate). Elucidation of the relationship between the zonation of hepatic fatty acid metabolism and the acinar expression of liver fatty acid binding protein should provide a more detailed understanding of the function of this protein.

Alanine Transaminase↗
PubMed1989

Increased sinusoidal volume and solute extraction during retrograde liver perfusion.

Retrograde isolated liver perfusion has been used to probe acinar functional heterogeneity, but the hemodynamic effects of backward flow have not been characterized. In this study, extraction of a long-chain fatty acid derivative, 12-N-methyl-7-nitrobenzo-2-oxa-1,3-diazol-amino stearate (12-NBDS), was greater during retrograde than during anterograde perfusion of isolated rat liver. To determine whether hemodynamic differences between anterograde and retrograde perfused livers could account for this finding, the hepatic extracellular space was measured for both directions of flow by means of [14C]sucrose washout during perfusion as well as by direct measurement of [14C]sucrose entrapped during perfusion. A three- to fourfold enlargement of the total hepatic extracellular space was found during retrograde perfusion by both approaches. Examination of perfusion-fixed livers by light microscopy and morphometry revealed that marked distension of the sinusoids occurred during retrograde perfusion and that this accounts for the observed increase in the [14C]sucrose space. These findings support the hypothesis that maximum resistance to perfusate flow in the isolated perfused rat liver is located at the presinusoidal level. In addition, increased transit time of perfusate through the liver and greater sinusoidal surface area resulting from sinusoidal distension may account for the higher extraction of 12-NBDS and possibly other compounds by retrograde perfused liver.

4-Chloro-7-nitrobenzofurazan↗
PubMed1986

Tissue expression of three structurally different fatty acid binding proteins from rat heart muscle, liver, and intestine.

Three structurally different 14-15 kDa fatty acid binding proteins have have been purified from rat liver, small intestinal epithelium, and heart muscle, and were quantitated using specific antisera in rat tissues. Heart muscle fatty acid binding protein comprised 5% of heart muscle cytosol protein and was also expressed in stomach, muscle, testis, ovary, kidney, brain, and adipose tissue, a pattern distinct from both liver protein (expressed in liver, small and large intestinal epithelium, and adipose tissue) and intestinal protein (expressed in small and large intestinal epithelium and stomach). Distinctive patterns of tissue expression of the three different fatty acid binding proteins suggest that they may perform different specific functions in fatty acid transport and metabolism.

Animals↗
PubMed1985

Turnover and short-term regulation of fatty acid binding protein in liver.

Rat hepatic fatty acid binding protein (hFABP) may play an important role in the intracellular transport and metabolism of fatty acids. Recent reports have suggested a substantial circadian variation in the amount of hFABP in liver, and a half-life of less than 2 h for this protein has been inferred. In the present study, the kinetics of hFABP turnover were examined directly. hFABP half-life measured after pulse labeling with NaH14CO3 was 3.1 days compared with 2.9 days for total cytosol protein. Following double-isotope labeling, the charge isoforms of hFABP showed similar rates of turnover, all of which were slower relative to whole cytosol protein turnover. Following a 48-h fast, total liver hFABP measured by immunoassay fell 65%, paralleling a 60% fall in total cytosol protein. Refeeding for 24 h did not lead to a significant recovery of either hFABP or total cytosol protein content. No significant change was observed in hFABP abundance between mid-light and mid-dark periods of a 24-h light-dark cycle. These studies showed that hFABP has a relatively slow rate of turnover and that it is not acutely modulated by dietary or diurnal influences.

Animals↗
PubMed1985

Regulation of the biosynthesis of two distinct fatty acid-binding proteins in rat liver and intestine. Influences of sex difference and of clofibrate.

Two distinct fatty acid-binding proteins (FABPs) have been identified in rat intestine, gFABP (15,063 Da) which is confined to intestinal epithelium and hFABP (14,184 Da) which is found in both liver and intestine. We have examined the influence of sex difference and the effect of clofibrate, both of which affect cellular fatty acid metabolism and hFABP levels, on the concentration, and mRNA levels of both hepatic and intestinal FABPs. In the liver, hFABP concentration was approximately 2-fold greater in females and in clofibrate-treated males than in untreated male rats. These differences were not accompanied by changes in the fractional turnover of the polypeptide but rather by parallel increases in hFABP mRNA. In the intestine, the two FABPs exhibited different regulatory responses. Intestinal hFABP turnover was 33% greater in females than in males, whereas mRNA concentration was 50% greater. Thus, unlike hFABP in liver, there was no sex-related difference in the steady-state level of hFABP in intestine. However, clofibrate treatment, similar to its effects in the liver, doubled intestinal hFABP protein and mRNA concentration. In contrast to hFABP, neither gFABP protein nor mRNA concentration were sex dependent, whereas clofibrate produced only a modest increase in gFABP concentration without significantly changing gFABP mRNA levels. The results indicate that the influence of sex difference and the effect of clofibrate on hepatic fatty acid metabolism are both associated with changes in hFABP synthesis mediated pretranslationally. The differential response of hFABP and gFABP in intestine suggests that these proteins play distinct roles in the cellular metabolism of fatty acids.

Animals↗
PubMed1984

Partial purification of molecular weight 12 000 fatty acid binding proteins from rat brain and their effect on synaptosomal Na+-dependent amino acid uptake.

High-affinity, Na+-dependent synaptosomal amino acid uptake systems are strongly stimulated by proteins which are known to bind fatty acids, including the Mr 12 000 fatty acid binding protein (FABP) from liver. To explore the possibility that such a function might be served by fatty acid binding proteins intrinsic to brain, we examined the 105000g supernatant of brain for fatty acid binding. Observed binding was accounted for mainly by components excluded by Sephadex G-50, and to a small degree by the Mr 12 000 protein fraction (brain FABP fraction). The partially purified brain FABP fraction contained a protein immunologically identical with liver FABP as well as a FABP electrophoretically distinct from liver FABP. Brain FABP fraction markedly stimulated synaptosomal Na+-dependent, but not Na+-independent, amino acid uptake, and also completely reversed the inhibition of synaptosomal Na+-dependent amino acid uptake induced by oleic acid. Palmitic, stearic, and oleic acids were endogenously associated with the brain FABP fraction. These data are consistent with the hypothesis that Mr 12 000 soluble FABPs intrinsic to brain may act as regulators of synaptosomal Na+-dependent amino acid uptake by sequestering free fatty acids which inhibit this process.

Amino Acids↗
PubMed1984

Myocardial perforation due to temporary transvenous pacing catheters in pediatric patients.

Over a 13-year period, 18 pediatric patients received temporary transvenous pacing catheters for symptomatic bradycardia due to complete atrioventricular block or sinoatrial node dysfunction. Right ventricular wall perforation occurred in two patients. The utility of two-dimensional echocardiography in the detection and assessment of myocardial perforation by temporary pacing catheters is discussed.

Adolescent↗