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J B Lowe

Publications and source records attributed to J B Lowe.

At least 145 records · Page 8Linked to original sources
PubMed1989

Isolation of a cDNA encoding a murine UDPgalactose:beta-D-galactosyl- 1,4-N-acetyl-D-glucosaminide alpha-1,3-galactosyltransferase: expression cloning by gene transfer.

We have developed a genetic approach to isolate cloned cDNA sequences that determine expression of cell surface oligosaccharide structures and their cognate glycosyltransferases. A cDNA library was constructed in a mammalian expression vector by using mRNA from a murine cell line known to express a UDPgalactose:beta-D-galactosyl-1,4-N-acetyl-D-glucosaminide alpha-1,3-galactosyltransferase [(alpha 1-3)GT; EC 2.4.1.151]. This library was transfected into COS-1 cells, which lack expression of (alpha 1-3)GT. Transfected cells containing functional (alpha 1-3)GT cDNAs were detected and isolated with a lectin that recognizes the surface-expressed glycoconjugate product of the (alpha 1-3)GT enzyme. One cloned (alpha 1-3)GT cDNA was rescued from lectin-positive transfected cells. This cDNA contains a single long open reading frame that predicts a 394-amino-acid protein. No significant primary structure similarities were identified between this protein and other known sequences. However, the protein predicts a type II transmembrane topology similar to two other mammalian glycosyltransferases. This topology places the large COOH-terminal domain within the Golgi lumen; this domain was shown to be catalytically active when expressed in COS-1 cells as a portion of a secreted protein A fusion peptide. Biochemical analysis confirmed that this enzyme catalyzes a transglycosylation reaction between UDP-Gal and Gal(beta 1-4)GlcNAc to form Gal(alpha 1-3)Gal(beta 1-4)GlcNAc. This cloning approach may be generally applicable to the isolation of cDNAs encoding other mammalian glycosyltransferases.

Amino Acid Sequence↗
PubMed1988

The effectiveness of a worksite self-help smoking cessation program: a randomized trial.

A 2 x 2 randomized, factorial pretest/posttest group design was used to evaluate the effectiveness of self-help smoking cessation methods at the worksite. The study investigated the effect of a multicomponent health education and skill intervention versus the effect of a monetary incentive to the employee for quitting. All employees received, in addition, a standardized self-help smoking cessation manual and maintenance manual. Following agreement to participate and a baseline smoking history, all participants were followed for 6 weeks, 6 months, and 12 months. Saliva was obtained for thiocyanate (SCN) analysis of smoking status. Of the estimated 2000 smokers at the site, 387 smokers were recruited. Employees were randomly assigned to one of four groups. Results of this random trial indicate that those employees receiving a multicomponent program were most successful in quitting and remaining abstinent. The monetary incentive appears to have no effect on quit rate.

Adult↗
PubMed1988

Strategy to diagnose monoclonal gammopathies in serum: high-resolution electrophoresis, immunofixation, and kappa/lambda quantification.

Identification of monoclonal gammopathies in serum has involved electrophoresis of serum proteins, immunoelectrophoresis (IEP), and quantification of IgG, IgA, and IgM. Recent innovations in technology--including high-resolution electrophoresis (HRE), immunofixation (IFX), and quantification of kappa- and lambda-containing immunoglobulins--allow for more rapid and precise assessment of serum for monoclonal proteins. We present a series of guidelines to determine when high-resolution electrophoresis and quantification of immunoglobulins (including kappa and lambda) are sufficient and when additional IFX is required to characterize the monoclonal gammopathy. Of the samples studied, 88% were correctly diagnosed by HRE with quantification of immunoglobulins and kappa/lambda; only 12% required that IFX be performed. The guidelines allow us to detect monoclonal gammopathies quicker and more efficiently by avoiding redundant IEP or IFX testing. For the vast majority of cases, these guidelines allow for a correct diagnosis within one day. After one year of follow-up since completion of the study, no undetected cases of monoclonal gammopathy have eventuated.

Blood Protein Electrophoresis↗
PubMed1987

Expression of rat intestinal fatty acid-binding protein in Escherichia coli. Purification and comparison of ligand binding characteristics with that of Escherichia coli-derived rat liver fatty acid-binding protein.

Rat intestinal fatty acid-binding protein (I-FABP) is an abundant, 15,124-Da polypeptide found in the cytosol of small intestinal epithelial cells (enterocytes). It is homologous to rat liver fatty acid-binding protein (L-FABP), a 14,273-Da cytosolic protein which is found in enterocytes as well as hepatocytes. It is unclear why the small intestinal epithelium contains two abundant fatty acid-binding proteins. A systematic comparative analysis of the ligand binding characteristics of the two FABPs has not been reported. To undertake such a study we expressed the coding region of a full length I-FABP cDNA in Escherichia coli and purified large quantities of the protein. We also purified rat L-FABP from a similar, previously described expression system (Lowe, J. B., Strauss, A. W., and Gordon, J. I. (1984) J. Biol. Chem. 259, 12696-12704). Analysis of fatty acids associated with each of the homogeneous E. coli-derived FABPs suggested that the two proteins differed in their ligand binding specificity and capacity. All of the fatty acids associated with I-FABP were saturated while 30% of the E. coli fatty acids bound to L-FABP were unsaturated (16:1, 18:1, 18:2). We directly analyzed the ability of I- and L-FABP to bind fatty acids of different chain length and degree of saturation using a hydroxyalkoxypropyl dextran-based assay. Scatchard analysis revealed that each mole of L-FABP can bind up to 2 mol of long chain fatty acid while each mole of I-FABP can bind only 1 mole of fatty acid. L-FABP exhibited a relatively higher affinity for unsaturated fatty acids (oleate, arachidonate) than for saturated fatty acid (palmitate). By contrast, we were not able to detect a significant difference in the affinity of I-FABP for palmitate, oleate, and arachidonate. Neither protein exhibited any appreciable affinity for fatty acids whose chain length was less than C16. The observed differences in ligand affinities and capacities suggest that these proteins may have distinct roles in metabolism and/or compartmentalization of fatty acids within enterocytes.

Amino Acid Sequence↗
PubMed1987

Crystallization of rat intestinal fatty acid binding protein. Preliminary X-ray data obtained from protein expressed in Escherichia coli.

Rat intestinal fatty acid binding protein has been expressed in Escherichia coli, purified with bound long chain fatty acids and crystals grown from solutions of polyethylene glycol 4000. The crystals are monoclinic, space group P2(1), a = 3638 A, b = 57.2 A, c = 31.9 A, and beta = 113.9 degrees. Each unit cell contains two monomers of this 132-residue, 15.1-kDa polypeptide. The crystals are remarkably resistant to x-ray damage. X-ray diffraction data have been observed to 2.0 A resolution. Platinum chloride was used to generate a potential isomorphous heavy atom derivative.

Animals↗
PubMed1987

Effectiveness of impersonal versus interpersonal methods to recruit employees into a worksite quit smoking program.

One of the first salient issues a worksite quit smoking program must face is how to motivate employees to enroll and participate. The purpose of this study was to determine the effectiveness of impersonal versus interpersonal recruitment strategies used by an ongoing worksite quit smoking program. One hundred and nineteen smokers who stated on a questionnaire that they would be either "strongly yes" or "yes" interested in participating in a quit smoking program were randomized into two groups. One group was sent letters by employee mail from the director of the quit smoking program. This letter briefly described the program and invited employees to participate. The other group received a personal phone call from the staff health educator inviting them to participate. Results indicate that of the 46 individuals randomly assigned to Group 1 who were sent letters, none responded to the invitation; while 37 of the 44 employees who received a personal phone call, 19 scheduled an appointment, 7 kept their appointments. These results indicate the possible increased effectiveness of an impersonal versus interpersonal communications in recruiting full-time smoking employees.

Female↗
PubMed1986

Clinical applications of gene probes in human genetic disease, malignancy, and infectious disease.

Recent developments in recombinant DNA technology have made possible the production of gene probes consisting of cloned gene segments, cloned segments of DNA linked to genes, and synthetic gene fragments. Several methods have been developed by which these probes may be used for the diagnosis of human disease. This technology has been outstandingly successful for prenatal diagnosis and carrier detection in many genetic diseases. These methods have also been successfully applied to the analysis of human malignancies, by providing for the determination of cell lineage and clonality in lymphoid neoplasms. Finally, these methods have shown potential for rapid and sensitive diagnosis of some infectious diseases.

B-Lymphocytes↗
PubMed1986

The nucleotide sequence of the rat liver fatty acid-binding protein gene. Evidence that exon 1 encodes an oligopeptide domain shared by a family of proteins which bind hydrophobic ligands.

We have determined the nucleotide sequence of the gene encoding rat liver fatty acid-binding protein (L-FABP). Previous structural studies have shown that L-FABP belongs to a family of low molecular weight cytosolic proteins which bind hydrophobic ligands. Rat L-FABP is the first member of this family whose genomic organization has been defined. The L-FABP transcription unit spans 3790 nucleotides and contains four exons (115, 173, 93, and 121 base pairs) interrupted by three introns (1454, 1224, and 610 base pairs). No other abundant mRNAs appear to be transcribed from sequences located within 4 kilobases 5' or 6.5 kilobases 3' of this gene. Sequence analyses have detected the presence of several related amino acid sequence blocks within L-FABP which may serve similar structural roles. A variety of computational techniques were used to compare the oligopeptides specified by each exon with other known members of the protein family. The results indicate that only the amino acid sequence present in the first exon is conserved among the homologous proteins. This suggests that the first exon may encode a shared structural and functional domain important in the interaction of these proteins with their ligands.

Amino Acid Sequence↗
PubMed1986

Use of a bogus pipeline method to increase accuracy of self-reported alcohol consumption among pregnant women.

Pregnant women (N = 220) attending urban maternity care clinics were randomly assigned to study groups to determine the effectiveness of a "bogus pipeline" method to increase the accuracy of behavioral self-reports of alcohol consumption. Results indicate a significant difference (p less than .025) between those who reported alcohol consumption and those who were told their behavioral self-report of alcohol consumption would be confirmed by a physiological test (bogus pipeline). Only 14% in the self-reported group said they currently used alcohol during pregnancy, whereas 27% in the bogus pipeline group reported consumption of alcohol during pregnancy. The results suggest that the use of the bogus pipeline may increase the accuracy of self-reported alcohol consumption data from a cohort of pregnant women.

Adult↗
PubMed1985

Analyzing the structures, functions and evolution of two abundant gastrointestinal fatty acid binding proteins with recombinant DNA and computational techniques.

The structures of intestinal and liver fatty acid binding proteins (FABPs) have been determined from an analysis of the nucleotide sequences of cloned cDNAs. The primary translation product of intestinal FABP mRNA contains 132 residues (Mr = 15 124). Liver FABP mRNA encodes a 127 amino acid polypeptide (Mr = 14 273). In vitro co-translational cleavage and translocation assays showed that neither sequence has a cleavable signal peptide or signal peptide equivalent - suggesting that the FABPs do not enter the secretory apparatus but rather are targeted to the cytoplasm. A variety of computational techniques were used to compare the two FABP sequences. The results indicate that liver and intestinal FABP are paralogous homologues. A superfamily of proteins was defined which includes the FABPs, the cellular retinol and retinoic acid binding proteins, the P2 protein of peripheral nerve myelin, and a polypeptide known as 422 whose synthesis is induced during differentiation of 3T3-L1 cells to adipocytes. No sequence homologies were noted between any of these small molecular weight cytosolic proteins and nonspecific lipid transfer protein (sterol carrier protein 2), phosphatidylcholine transfer protein, serum albumin or apolipoprotein AI. The FABPs may have structural features responsible for lipid-protein interactions that are not present in these non-homologous sequences. The distribution of intestinal and liver FABP mRNAs in adult rat tissues and the changes in FABP gene expression which occur during gastrointestinal development support the notion that these proteins are involved in fatty acid uptake, transport and/or compartmentalization. However, differences in tissue distribution and periods of non-coordinate expression during gastrointestinal ontogeny suggest that the two FABPs have distinct functions. The relationship between intestinal and liver FABPs and similar sized cytosolic FABPs isolated from brain, skeletal and cardiac muscle remains unclear. Recombinant DNA techniques combined with comparative sequence analyses offer a useful approach for defining unique as well as general structure-function relationships in this group of fatty acid binding proteins.

Amino Acid Sequence↗
PubMed1985

Human liver fatty acid binding protein. Isolation of a full length cDNA and comparative sequence analyses of orthologous and paralogous proteins.

We have determined the primary structure of human liver fatty acid binding protein from an analysis of a full length cDNA. This 127-residue 14,178-Da protein exhibits a high degree of sequence conservation when compared to its orthologous homologue, rat liver fatty acid binding protein. It appears likely that this polypeptide arose from two intragenic duplication events. Using a variety of computational techniques, we were unable to find any evidence of amphipathic alpha helical domains in this protein nor any sequence similarities to apolipoproteins and serum albumins. A family of paralogous proteins was defined, whose members share a remarkable degree of sequence homology with share a remarkable degree of sequence homology with human liver fatty acid binding protein. These include rat intestinal fatty acid binding protein, the cellular the P2 protein of myelin. It appears that the small cytosolic fatty acid binding proteins have evolved structural features necessary for lipid-protein interaction which are different from those present in some familiar and better studied extracellular sequences.

Amino Acid Sequence↗
PubMed1985

Tissue specific expression and developmental regulation of two genes coding for rat fatty acid binding proteins.

We have examined the tissue distribution and developmental regulation of two low molecular weight cytosolic fatty acid binding proteins. Based on their initial site of isolation, they have been referred to as liver and intestinal fatty acid binding proteins (FABP). Cloned cDNAs were used to probe blots of RNAs extracted from a wide variety of adult rat tissues as well as small intestine and liver RNA obtained from fetal, suckling, and weaning animals. The highest concentrations of "liver" FABP mRNA were found in small intestine and liver. "Intestinal" FABP mRNA is most abundant in small bowel RNA while only trace amounts were encountered in liver. Both mRNAs were detectable in stomach, colon, pancreas, spleen, lung, heart, testes, adrenal, and brain RNA at 1-8% the concentrations observed in small intestine. Accumulation of both mRNAs in the small intestinal epithelium increases during development. The mRNAs are first detectable between the 19th and 21st day of gestation. They undergo a coordinated 3-4-fold increase in concentration within the first 24 h after birth. Thereafter, gut levels of intestinal FABP mRNA remain constant during the suckling period while liver FABP mRNA increases an additional 2-fold. Liver FABP mRNA levels are also induced in hepatocytes during the first postnatal day but subsequently do not change during the suckling and weaning phase, despite marked alterations in hepatic fatty acid metabolism. These observations support the concept that the major role of these proteins is to facilitate the entry of lipids into cells and/or their subsequent intracellular transport and compartmentalization. The data also raise questions about the identity of extragastrointestinal FABPs.

Aging↗
PubMed1984

Expression of a mammalian fatty acid-binding protein in Escherichia coli.

Rat liver fatty acid-binding protein (FABP) is a 14,200-Da polypeptide that is abundantly represented in the cytosol of liver and small intestinal epithelial cells. It may play an important role in the intracellular transport and metabolism of fatty acids. We have recently determined its sequence from an analysis of cloned cDNAs (Gordon, J.I., Alpers, D.H., Ockner, R. K., and Strauss, A.W. (1983) J. Biol. Chem. 258, 3356-3363). With the availability of full-length cloned FABP cDNAs, genetic manipulation of the coding region introduced into an appropriate expression vector could provide a powerful tool for analyzing the molecular details of fatty acyl-protein interaction. We, therefore, have inserted the coding sequence of rat FABP cDNA into a prokaryotic expression vector. Synthetic oligodeoxynucleotides were used to "properly" space the initiator methionine residue downstream from a Shine-Dalgarno ribosome-binding site. FABP transcription in the chimeric plasmid was under the direction of the leftward promotor of phage lambda. Promotor activity in turn was regulated by a thermolabile repressor specified by a defective lambda prophage contained in the host chromosome. When grown at permissive temperatures, rat liver FABP represented approximately 0.8% of radiolabeled soluble bacterial proteins. Edman degradation of FABP purified from Escherichia coli lysates indicated that it was intact. However, its NH2 terminus was not acetylated as it is in mammalian tissues. A frameshift mutation was introduced in vitro into the coding region of FABP cDNA. The effects of this on fatty acyl-protein interaction were examined using a solid phase (oleic acid-Sepharose) binding assay. Amino acid sequence rearrangements in the COOH-terminal region of rat liver FABP had a significant effect on its ability to bind fatty acids as well as on its stability in bacteria.

Amino Acid Sequence↗
PubMed1983

Antianginal efficacy of perhexiline maleate in patients refractory to beta-adrenoreceptor blockade.

We performed a double-blind controlled crossover trial of perhexiline maleate versus identical placebo in daily doses of 100-400 mg in 20 male patients who were severely limited with angina pectoris despite therapy with beta-adrenoreceptor blockers. All patients had documented coronary artery disease and were awaiting coronary artery bypass grafting. Beta-blocker therapy was continued unchanged. A significant response compared to placebo was evident after 100 mg of perhexiline, and incremental therapeutic effects were evident up to 400 mg. The mean weekly angina rate fell from 18.2 +/- 2.8 basal to 6.2 +/- 1.5 on 200 mg (P less than 0.05) to 2.8 +/- 0.9 on 400 mg perhexiline (P less than 0.05). Nitroglycerin consumption fell in parallel. The mean exercise duration increased from 261 +/- 57 sec to 384 +/- 75 sec (P less than 0.05). Five patients became asymptomatic on perhexiline, and the number of pain-free days increased 100% (P less than 0.01) compared to placebo. No patient experienced hypotension or heart failure. This study shows that the addition of perhexiline to beta-adrenoreceptor antagonists in patients with severe angina pectoris is effective and represents an alternative therapy.

Adrenergic beta-Antagonists↗