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Biomedical subjects

T Cole

Publications and source records attributed to T Cole.

At least 91 records · Page 5Linked to original sources
PubMed1987

Development of an imaging flow cytometer.

A cell analyzer that combines the characteristics of image cytometry and flow cytometry is being designed and constructed at the University of Sydney. This paper describes the image acquisition and processing components and some preliminary applications. Cells stained by a fluorescent dye and suspended in a liquid medium are conveyed by a hydraulic system to a flow channel assembly, where they are detected and illuminated by a laser beam. A two-dimensional charge-coupled device is used to acquire the cell images. Image processing and classification is to be carried out by a special-purpose computer comprising an array of four conventional microprocessors and a highly parallel processor consisting of an array of 32 X 32 processing elements. The analyzer will be capable of using morphologic, immunologic and biochemical information to classify and sort up to 500 cells per second. Because of its unique characteristics, the instrument will be of particular use in tumor heterogeneity studies.

Flow Cytometry↗
PubMed1986

Specific binding and proteolytic inactivation of bradykinin by membrane vesicles from pig intestinal smooth muscle.

A preparation of closed membrane vesicles derived from the longitudinal and circular smooth muscle of pig small intestine was enriched eight-fold in the activity of 5'-nucleotidase and six-fold in the activity of peptidyl dipeptidase A relative to the tissue homogenate. The membrane vesicles specifically bound [3H]bradykinin and the concentration of bradykinin required to inhibit 50% binding was 0.76 +/- 0.05 nM. This concentration was not significantly different from the corresponding concentration of lysyl-bradykinin (0.45 +/- 0.13 nM) but was less (P less than 0.05) than the concentration of methionyl-lysyl-bradykinin (1.25 +/- 0.10 nM). The concentration of des-Arg9 bradykinin (7.5 microM) required for 50% inhibition was greater than 10(3) times less than bradykinin indicating the presence of a B2-type receptor. The membrane vesicles also degraded bradykinin and the principal metabolite was identified as bradykinin. Des-Arg1 bradykinin, des-Arg9 bradykinin and bradykinin were also formed in low yield. Cleavage of the Pro7-Phe8 bond was inhibited by phosphoramidon but not by enalapril or captopril indicating that proteolytic inactivation of bradykinin in the muscle layer of the intestine is mediated through endopeptidase 24.11 ("enkephalinase") but not through peptidyl dipeptidase A ("angiotensin-converting enzyme").

5'-Nucleotidase↗
PubMed1986

Computer-aided three-dimensional reconstruction of nematode embryos from EM serial sections.

Embryos of the nematode Caenorhabditis elegans were serially sectioned and photographed in the electron microscope (EM). The micrographs were used to produce three-dimensional (3D) reconstructions. Size and position of each nucleus were entered into a computer, displayed as spheres, and were color-coded to indicate lineage membership. Location in space and position in the cell cycle are generally adequate criteria to identify cells. The reconstructions allow visualization of lineage-related topographic patterns and ultrastructural analysis of differently determined cells.

Animals↗
PubMed1986

Proteolytic inactivation of substance P and neurokinin A in the longitudinal muscle layer of guinea pig small intestine.

Membrane vesicles, showing a 21 +/- 2-fold enrichment in the activity of 5'-nucleotidase and a 11 +/- 4-fold enrichment in the activity of angiotensin-converting enzyme relative to homogenate, were prepared from the myenteric plexus-containing longitudinal muscle layer of guinea pig ileum. Incubation of the vesicles with substance P and neurokinin A led to degradation of the peptides, and metabolites were isolated by reverse-phase HPLC and identified by amino acid composition. Cleavages of substance P between Glu6-Phe7, Phe7-Phe8, and Gly9-Leu10 and of neurokinin A between Gly8-Leu9 were observed and could be inhibited in a dose-dependent manner by phosphoramidon, an inhibitor of neutral endopeptidase 24.11. Formation of these metabolites was not completely inhibited by this agent, indicating that a phosphoramidon-insensitive form of endopeptidase 24.11 was present in the gut. Substance P was resistant to degradation by aminopeptidases, but neurokinin A was a substrate for bestatin-sensitive aminopeptidase(s), so that the neurokinin A (3-10) fragment represented the predominant metabolite in the chromatograms. The rate of formation of all the metabolites was not inhibited by enalapril and not enhanced by an increased Cl- concentration, indicating that angiotensin-converting enzyme was unimportant in the degradation process. Degradation of neurokinin A by the vesicles (Km 30 microM; Vmax 7.2 +/- 0.8 nmol min-1 mg of protein-1) was more rapid than degradation of substance P (Km 25 microM; Vmax 4.4 +/- 0.4 nmol min-1 mg of protein-1).

Aminopeptidases↗
PubMed1986

Specific binding and degradation of somatostatin by membrane vesicles from pig gut.

Plasma membrane vesicles were prepared from the basolateral face of pig small intestinal epithelial cells and were enriched in the activity of Na+-K+-ATPase (9-fold relative to the cell homogenate) and ranged in size from 0.15 to 0.40 micron diam. Incubation of somatostatin-14 and [125I-Tyr11]-somatostatin-14 with the vesicles at 37 degrees C resulted in rapid proteolytic degradation of the peptides. Metabolites were isolated by reverse-phase high-performance liquid chromatography and identified by amino acid composition. Cleavages between Ala1-Gly2, Phe6-Phe7, Phe7-Trp8, and Thr10-Phe11 were observed, indicative of aminopeptidase and endopeptidase action. Degradation was inhibited by 1,10-phenanthroline and by bacitracin, and in the presence of these inhibitors and at 21 degrees C binding of [125I-Tyr11]somatostatin-14 to the vesicles was observed. Binding was inhibited in a concentration-dependent manner by somatostatin-14 (half-maximal inhibition at 2.0 +/- 0.1 nM) and by somatostatin-28 (0.8 +/- 0.1 nM) but not by structurally unrelated peptides. The rate of degradation of [125I-Leu8, D-Trp22, Tyr25]somatostatin-28 by basolateral membrane was less than 20 fold that of [125I-Tyr11]somatostatin-14 and a two- to three-fold enhanced binding to the vesicles was observed. Analysis of the inhibition of binding of this analogue by somatostatin-28 indicates the presence of single class of binding site with Kd = 1.3 +/- 0.3 nM. Rapid degradation but no specific binding of somatostatin-14 by brush-border membranes was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1986

Acute chest syndrome in children with sickle cell disease. A retrospective analysis of 100 hospitalized cases.

We reviewed the clinical features of 100 cases of the sickle cell chest syndrome in 57 pediatric patients hospitalized with radiographic findings of pulmonary or pleural disease. Pulmonary infiltration was more common in the lower lobes (86%) than in the upper (25%) or middle lobes (22%). Pleural effusions were present in 38% of cases. Chest syndrome was recognized on presentation in 79% of cases, but was recognized only later in 21% of patients admitted for other indications. Patients recognized initially were more often febrile on admission (68%) than were subsequently recognized patients (33%) (p less than 0.01), but fever eventually occurred in 99 of 100 cases. Pain was an antecedent or coincident problem in 67% of cases. Median hospital stay was 7 days in those 58 cases in which narcotics were given, but only 4 days in those 42 cases in which narcotics were not administered (p less than 0.001). Polyvalent pneumococcal vaccine had been administered to 44 of our 57 patients at some time before their hospitalizations, and 18 patients had been on oral penicillin prophylaxis. Blood was cultured in 93 cases and in only two instances grew Streptococcus pneumoniae. Serologic evidence of Hemophilus influenzae type b infection was found in two additional patients. We conclude that the sickle cell chest syndrome is an acute febrile pulmonary disease frequently associated with pain and/or narcotic analgesic therapy but infrequently associated with proven bacterial infection.

Adolescent↗
PubMed1985

Major acute phase alpha 1-protein of the rat is homologous to bovine kininogen and contains the sequence for bradykinin: its synthesis is regulated at the mRNA level.

The complete amino acid sequence of major acute phase alpha 1-protein of the rat (MAP) was derived from the nucleotide sequence of cloned cDNA. Amino acid analysis and partial sequencing supported the predicted sequence. The amino acid compositions of MAP and rat low-Mr kininogen are identical within experimental variation. The sequence is homologous (60%) to that of bovine low-Mr kininogen and both proteins carry the sequence for the vasoactive nonapeptide bradykinin in their C-terminal region. The rate of synthesis of MAP and the levels of MAP mRNA change coordinately during the acute phase response to inflammation.

Acute-Phase Proteins↗
PubMed1985

Major acute-phase alpha(1)protein in the rat: structure, molecular cloning, and regulation of mRNA levels.

Rat major acute-phase alpha(1)protein (MAP) was characterized by determining its secondary structure, ligand binding and partial amino acid sequence. A cDNA clone expressing MAP and coding for the entire mature protein was isolated from a cDNA library in E. coli prepared from rat liver mRNA. By hybridization to nick translated cDNA, mRNA for MAP was found only in liver, where it increased 17-fold during acute inflammation. Constant proportions of rates of leucine incorporation into MAP over mRNA levels in liver indicated that the regulation of the synthesis of MAP is due to a change in the rate of synthesis and/or the stability of mRNA for MAP, but not the rate of its translation.

Acute-Phase Proteins↗
PubMed1985

Biological and biochemical characterization of a somatostatin-producing human carcinoma established by heterotransplantation.

A somatostatin-producing human carcinoma cell line was established by heterotransplantation into athymic nude mice. The original material, which was derived from a colon tumor of a patient who had previously had bilateral ovarian tumors contained 66 ng extractable somatostatin/g tissue. Somatostatin-producing cells could be identified by immunohistochemistry within the first tumor transplants. Although initially the somatostatin concentration was low (14 ng/g) a progressive increase was observed with each successive transplantation so that after 10 passages it reached a level of 127 ng/g tissue. Analysis of tumor extracts by gel filtration and high-performance liquid chromatography indicated that somatostatin-14 was the only molecular form produced by the original and by the transplanted tumor after multiple passages. This result demonstrates that the tumor has the ability to constitutively express the prosomatostatin gene and to process the primary translation product to somatostatin-14.

Animals↗
PubMed1984

A membrane protein encoded by Epstein-Barr virus in latent growth-transforming infection.

The nucleotide sequence of an Epstein-Barr virus gene expressed in latently infected growth-transformed cells is known to include a long open reading frame containing a 33-base-pair repeat element. A bacterial fusion protein constructed from a portion of the reading frame and Escherichia coli beta-galactosidase was used to produce sera in rabbits against the previously unidentified gene product. The viral protein detected with these sera in latently infected cells varies in size with the number of copies of the DNA repeat element. Translation of the RNA in vitro yields a protein of similar size. As expected from its primary sequence, the protein is a membrane protein. Immunofluorescence studies with the rabbit antisera suggest that the protein is in the plasma membrane. Thus, this protein could be the lymphocyte-determined membrane antigen (LYDMA) responsible for the generation of T-cell immunity to latently infected cells.

Cell Membrane↗
PubMed1983

The interaction of carbamylated low-density lipoprotein with cultured cells. Studies with human fibroblasts, rat peritoneal macrophages and human monocyte-derived macrophages.

We determined the effects of various degrees of chemical modification of low-density lipoprotein (LDL) on its interaction with receptors present on human fibroblasts, human monocyte-derived macrophages and rat peritoneal macrophages. We isolated LDL (d = 1.019-1.063 g/ml) and carbamylated different numbers of lysine residues and tested its cell-interactive properties, including binding, degradation, and stimulation of [3H]oleate incorporation into cholesteryl oleate. Small carbamylation of LDL (approximately 1-2% of lysine residues) resulted in a reduced ability (70-80% of control) to displace 125I-labeled LDL from fibroblast receptors. Modification of 12.5-25% of lysine residues resulted in a marked increase in the ability of LDL to interact with scavenger receptors and an almost total loss in the ability to interact with apolipoprotein B-E receptors. Acetylated LDL and malondialdehyde-modified LDL inhibited competitively the degradation of 125I-carbamylated LDL by human macrophages. Thus, the extent of modification plays an important role in recognition of modified LDL by scavenger receptors. There also seems to be a range of modification over which LDL is not yet recognized by the scavenger receptor, but its interaction with the apolipoprotein B-E receptor is markedly reduced. This perhaps explains how a small in vivo modification of LDL can result in an increase in residence time of LDL in the subendothelial tissue which can lead to further local interactions, ultimately increasing the atherogenicity of the LDL particle.

Animals↗
PubMed1983

Weight gain and movement patterns of very low birthweight babies nursed on lambswool.

34 very low birthweight babies (mean 1143 g) in incubators were randomly assigned to be continuously nursed on lambswool (n = 17) or ordinary cotton sheets (n = 17). The weight gain for the periods when babies were well was significantly larger for the wool group, 22.7 g/day vs 18.6 g/day for cotton control (p less than 0.02). The overall weight gain (which included weight change during periods of illness) revealed a similar picture in favour of the wool group, 21.5 g/day vs 18.2 g/day (p less than 0.05). Movement patterns for the two groups showed no differences, but for all babies a strong correlation was noted between moving and lying suspine (p less than 0.001), having eyes open (p less than 0.001), a cooler incubator (p less than 0.01), and faster weight gain (p less than 0.01). Lambswool seems to have advantages over cotton sheets as a bedding material for very low birth weight babies.

Animals↗
PubMed1982

Chronic ectopic pregnancy.

Chronic ectopic pregnancy is often an enigma and a correct diagnosis is frequently not made until exploratory laparotomy. Hemodynamic stability, chronicity of symptoms, and a high incidence of false-negative pregnancy tests and culdocentesis results are clinical characteristics distinguishing it from the more common acute ectopic pregnancy. Dense adhesions and occasional abscess formation and surgical features that characterize the chronic ectopic pregnancy. Approximately 6% of ectopic pregnancies are chronic.

Adult↗