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D M Swallow

Publications and source records attributed to D M Swallow.

At least 55 records · Page 3Linked to original sources
PubMed1994

Expression of human intestinal mRNA transcripts during development: analysis by a semiquantitative RNA polymerase chain reaction method.

To study the relative expression of lactase, sucrase-isomaltase, dipeptidyl peptidase IV, and the Na(+)-dependent glucose transporter mRNA transcripts in small samples of human tissue, we have developed and validated a very simple semiquantitative RNA polymerase chain reaction method that can be used on as little as 5-10 mg of tissue. Here we report the use of this method to study the expression of these genes at different stages of development, in different tissues and in different parts of the intestine, in comparison with another intestinal marker, the colon-specific transcript of carbonic anhydrase 1. Lactase, sucrase-isomaltase, and the Na(+)-dependent glucose transporter mRNA are expressed predominantly in the small intestine, although lactase mRNA is expressed at a very low level in fetuses. Dipeptidyl peptidase IV mRNA shows a much wider tissue distribution. Sucrase-isomaltase and dipeptidyl peptidase IV mRNA are present at high levels in fetal colon and also at surprisingly high levels in adult colon. Lactase mRNA, on the other hand, is present at very low levels in fetal colon and is not detectable at all in adult colon. The Na(+)-dependent glucose transporter mRNA in contrast is expressed at higher levels in the adult colon than in the fetal colon. This is also the case for the carbonic anhydrase 1 transcript, although this transcript is not expressed in the small intestine. Thus, each of these genes shows different developmental and cell-specific regulation.

Base Sequence↗
PubMed1993

Characterisation of an epitope recognised by a monoclonal antibody against horse alcohol dehydrogenase using peptides synthesised on solid support.

Immunological analysis, using the Pepscan technique, of the tetradecapeptide, Pro344-Glu357 (PLITHVLPFEKINE), from horse liver alcohol dehydrogenase has identified a five amino acid sequence, HVLPF, which binds a monoclonal antibody. The epitope seems to be rather flexible with only two of the amino acids, Pro and Phe, having the characteristics of contact residues. However, the presence of the adjacent glutamic acid residue as part of the Pepscan peptide has a dramatic negative neighbourhood effect and inhibits binding. This highlights the potential risk of missing an epitope altogether when using the Pepscan procedure for epitope mapping.

Alcohol Dehydrogenase↗
PubMed1993

Human regeneration protein/lithostathine genes map to chromosome 2p12.

The pancreatic stone protein (lithostathine) secreted by the exocrine pancreas is an inhibitor of CaCO3 crystal growth. This protein, which is also present in endocrine pancreas, has also been called the regeneration protein (reg). Here we report the mapping of the REG gene to chromosome 2 using the polymerase chain reaction for the specific amplification of human reg sequences in rodent/human somatic cell hybrid DNA. A regional assignment has been made by in situ hybridization to metaphase chromosomes using two different fluorescently labelled genomic probes corresponding to the REG gene and a related gene REGL. Both probes hybridized to chromosome 2p12 suggesting the tandem organization of these genes.

Animals↗
PubMed1993

Regional localization of the lactase-phlorizin hydrolase gene, LCT, to chromosome 2q21.

The gene LCT which codes for the intestinal disaccharidase lactase-phlorizin hydrolase has previously been mapped, using somatic cell hybrids and linkage analysis, using the CEPH families, to chromosome 2. We describe here the regional localization of LCT to chromosome 2q21 by polymerase chain reaction (PCR) analysis of somatic cell hybrids and in situ hybridization. LCT is closely linked to D2S44, with a lod score of 30.6 at theta = 0.10.

Animals↗
PubMed1993

Regional localization of the gene coding for the GM2 activator protein (GM2A) to chromosome 5q32-33 and confirmation of the assignment of GM2AP to chromosome 3.

The gene coding for the GM2 activator protein (GM2A) was previously mapped by us to chromosome 5 by an ELISA-based technique. Here we confirm this assignment using a PCR analysis of somatic cell hybrids and describe a regional localization to chromosome 5q32-33 by in situ hybridization. We also confirm the assignment of a pseudogene GM2AP to chromosome 3.

Animals↗
PubMed1993

A monoclonal antibody to alcohol dehydrogenase cross-reacts with human complement component C3.

A monoclonal antibody (mHADH1) against alcohol dehydrogenase was found to cross-react with an abundant protein in human serum. This cross-reacting material was identified unambiguously as the third component of complement (C3), probably part of the alpha-chain, by immunoblotting and immunoprecipitation experiments. The known ADH epitope, HVLPF, recognized by the monoclonal antibody is not, however, present in the C3 sequence.

Alcohol Dehydrogenase↗
PubMed1992

Regional localization of the intestinal mucin gene MUC3 to chromosome 7q22.

The gene MUC3 which codes for a mucin expressed in intestine (Gum et al. 1990) has previously been mapped, using somatic cell hybrids, to chromosome 7. We describe here the regional localization of MUC3 to chromosome 7q22 by in situ hybridization. Preliminary linkage analysis using CEPH (Centre d'Etude du Polymorphisme Humain) families supports this assignment and places MUC3 in the same linkage group as COL1A2 and CFTR.

Amino Acid Sequence↗
PubMed1991

Differential mucin gene expression in human pancreatic and colon cancer cells.

The purpose of this study was to determine the quantity and nature of the mucins synthesized and secreted by four different pancreatic cancer cell lines. Well- to moderately-differentiated SW1990 and CAPAN-2 human pancreatic cancer cells were found to produce more high-Mr glycoprotein (HMG) than less-differentiated MIA PaCa-2 and PANC-1 cells. Most of the labelled HMG was secreted within 24 h. The results of chemical and enzymic degradation, ion-exchange chromatography and density-gradient centrifugation indicated that the HMG in SW1990 and CAPAN-2 cells has the properties expected for mucins, whereas much of the HMG in MIA PaCa-2 and PANC-1 cells may not be mucin, but proteoglycan. These results are consistent with immunoblots and Northern blots showing the presence of apomucin and apomucin mRNA in SW1990 and CAPAN-2 cells, but not in MIA PaCa-2 and PANC-1 cells. The Western blots and Northern blots also show that SW1990 and CAPAN-2 cells, like breast cancer cells, have the mammary-type apomucin and mRNA coded by the MUC1 gene, but lack the intestinal type apomucin and mRNA coded by the MUC2 gene. In contrast, the colon cancer cell lines tested in culture express apomucin and mRNA coded by MUC2 but not by MUC1.

Adenocarcinoma↗
PubMed1990

Molecular cloning of cDNAs derived from a novel human intestinal mucin gene.

A human small intestinal lambda gt11 cDNA library was screened with antibodies to deglycosylated small intestinal mucin. Four partial cDNA clones were isolated that define a novel human mucin gene. These include two partial cDNA clones, SIB 124 and SIB 139, that contain 51 nucleotide tandem repeats which encode a seventeen amino acid repetitive peptide with a consensus sequence of HSTPSFTSSITTTETTS. SIB 139 hybridized to messages produced by small intestine, colon, colonic tumors and also by high mucin variant LS174T colon cancer cells. The gene from which cDNAs SIB 124 and SIB 139 are derived (proposed name MUC 3) maps to chromosome 7, distinct from other known human mucin genes.

Amino Acid Sequence↗
PubMed1990

Pyrimidine 5'-nucleotidase activity in normal and deficient human lymphoblastoid cells.

Two distinct pyrimidine 5'-nucleotidases (UMPH-1 and UMPH-2) have previously been detected in human erythrocytes; UMPH-1 is deficient in a haemolytic anaemia, while UMPH-2 is unaffected. Only the erythrocyte shows pathological effects in this disorder. Here we have studied lymphoblastoid cell lines from control and UMPH-1 deficient patients to determine whether UMPH-1 can be detected in lymphoblastoid cells and whether the deficiency of UMPH-1 results in any measurable metabolic effects. Both UMPH-1 and a UMPH-2-like activity were found to be present in control lymphoblastoid cells. UMPH-1 was undetectable in the patients' cells; minor but significant changes were found in the pyrimidine nucleotide and nucleoside pools in the cells.

5'-Nucleotidase↗
PubMed1990

Isolation of a cDNA probe for the human intestinal dipeptidylpeptidase IV and assignment of the gene locus DPP4 to chromosome 2.

We report the nucleotide sequence and derived amino-acid sequence of a cDNA clone encoding the 3' end of human intestinal dipeptidylpeptidase IV (DPP-IV). This cDNA probe identifies a 4 kb mRNA in the human colon cancer cell line Caco-2. We demonstrate here an extensive homology between this human DPP-IV cDNA and the recently published rat liver DPP-IV cDNA. Using the human DPP-IV cDNA to probe genomic DNA from a panel of somatic cell hybrids we have assigned the gene encoding human DPP-IV to chromosome 2.

Animals↗
PubMed1990

Assignment of the polymorphic intestinal mucin gene (MUC2) to chromosome 11p15.

A cDNA coding for a mucin expressed in intestine has recently been cloned (Gum et al. 1989). We describe here the use of this cDNA to map the gene (MUC2) to human chromosome 11 using somatic cell hybrids, and to make the regional localization to 11p15 by in situ hybridization. Analysis of the CEPH (Centre d'Etude du Polymorphisme Humain) families revealed that MUC2 forms part of the tight linkage group on 11p15 which contains HRAS, INS, TH and HBBC.

Animals↗
PubMed1989

Production of monoclonal antibodies to lactate dehydrogenase (LDH) isoenzymes for immunohistochemical study on fixed tissue section.

Purified lactate dehydrogenase (LDH) isoenzyme 1 (H or B subunits) and isoenzyme 5 (M or A subunits) were used to prepare monoclonal antibodies (MAb) suitable for immunohistochemical detection on formalin fixed paraffin-embedded tissue sections. In the initial fusions, screening of the antibodies was based on enzyme linked immunosorbent assay (ELISA) against the immunogens. None of the antibodies obtained was satisfactory. There were various problems related to specificity, crossreactivity, affinity and also the properties of the monoclonal antibody itself. Using a combined system involving more than one method for screening, two suitable monoclonal antibodies, MAb65 (to H-type LDH) and MAb25 (to M-type LDH) were selected. Both antibodies reacted specifically with corresponding LDH isoenzymes as shown in a series of tests. Their reactivity in sections of formalin fixed paraffin-embedded tissue indicated that both antibodies are suitable reagents for immunohistochemical studies.

Animals↗
PubMed1989

An investigation of the properties and possible clinical significance of the lysosomal alpha-glucosidase GAA*2 allele.

Properties of the acid alpha-glucosidase, GAA2, the product of the GAA*2 allele have been compared with those of the common allele product GAA1, GAA2 has an altered affinity for glycogen but resembles GAA1 in its affinity for low molecular weight substrates, and also in its processing, as judged by immunoblot analysis of the denatured polypeptides. Starch gel electrophoretic analysis of fibroblasts from 15 patients with late onset glycogen storage disease type II (GSDII) failed to reveal either homozygotes or heterozygotes for the GAA*2 allele (GAA2-2 or GAA2-0) providing evidence that neither of these genotypes lead to late onset GSDII despite the impaired activity of the enzyme towards glycogen.

Alleles↗
PubMed1989

An investigation of the possible influence of neutral alpha-glucosidases on the clinical heterogeneity of glycogenosis type II.

The lysosomal storage disorder glycogenosis type II, caused by a deficiency of lysosomal alpha-glucosidase, is very heterogeneous in its clinical presentation. It has been suggested that this heterogeneity may be due to differential expression of neutral alpha-glucosidases. We have therefore analysed the activity of the major neutral alpha-glucosidases in cultured fibroblasts or muscle cells from 26 patients with glycogenosis type II. The results indicate that there is no correlation between the expression of neutral alpha-glucosidase isoenzymes and the clinical phenotype of this disease.

Cells, Cultured↗