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J B Lowe

Publications and source records attributed to J B Lowe.

At least 73 records · Page 4Linked to original sources
PubMed1997

Molecular cloning, chromosomal assignment and tissue-specific expression of a murine alpha(1,2)fucosyltransferase expressed in thymic and epididymal epithelial cells.

Terminal Fucalpha(1-2)Galbeta epitopes have been proposed to play significant roles in cell-cell interactions in development, cell adhesion, and malignant transformation. To begin to investigate the regulation and function of alpha(1-2)fucosylated epitopes in an animal model, we have isolated and characterized a mouse genomic DNA segment encoding a protein orthologous to the human H blood group locus alpha(1,2)fucosyltransferase (FUT1). This segment maintains an open reading frame encoding 376 amino acids sharing 75% sequence identity with the enzyme encoded by human FUT1, and 55% sequence identity with the enzyme encoded by the human Secretor blood group locus (FUT2). Expression of the open reading frame in COS-7 cells yields an alpha(1,2)fucosyltransferase activity with a Km of 7.6 mM for phenyl-beta-d-galactoside. Southern blotting and interspecific backcross analyses indicate that this murine locus represents a single copy sequence mapping to a novel locus 2.1 centimorgans from the Klk1 locus, in a region of homology between mouse chromosome 7 and the human FUT1 locus on the long arm of chromosome 19. Mouse FUT1 yields a 2.8 kb mRNA transcript identifiable in many organs, including thymus, lung, stomach, pancreas, small intestine, colon, uterus and epidiymis. Hybridization analyses in situ localize expression of FUT1 transcripts to thymic medullary and epididymal epithelial cells, implying that this gene determines the expression of cell surface Fucalpha(1-2)Galbeta epitopes in these tissues.

Amino Acid Sequence↗
PubMed1997

Expression of human H-type alpha1,2-fucosyltransferase encoding for blood group H(O) antigen in Chinese hamster ovary cells. Evidence for preferential fucosylation and truncation of polylactosamine sequences.

The human H(O) blood group is specified by the structure Fucalpha1-2Galbeta1-R, but the factors regulating expression of this determinant on cell surface glycoconjugates are not well understood. To learn more about the regulation of H blood group expression, cDNA encoding the human H-type GDPFuc:beta-D-galactoside alpha1, 2-fucosyltransferase (alpha1,2FT) was stably transfected into Chinese hamster ovary (CHO) cells. The new cell line, designated CHO(alpha1,2)FT, expressed surface neoglycans containing the H antigen. The structures of the fucosylated neoglycans in CHO(alpha1, 2)FT cells and the distribution of these glycans on glycoproteins were characterized. Seventeen percent of the [3H]Gal-labeled glycopeptides from CHO(alpha1,2)FT cells bound to the immobilized H blood group-specific lectin Ulex europaeus agglutinin-I (UEA-I), whereas none from parental CHO cells bound to the lectin. The glycopeptides from CHO(alpha1,2)FT cells binding to UEA-I contained polylactosamine [3Galbeta1-4GlcNAcbeta1-]n with the terminal sequence Fucalpha1-2Galbeta1- 4GlcNAc-R. Fucosylation of the polylactosamine sequences on complex-type N-glycans in CHO(alpha1, 2)FT cells caused a decrease in both sialylation and length of polylactosamine. Unexpectedly, only small amounts of terminal fucosylation was found in diantennary complex-type N-glycans. The O-glycans and glycolipids were not fucosylated by the H-type alpha1, 2FT. Two major high molecular weight glycoproteins, one of which was shown to be the lysosome-associated membrane glycoprotein LAMP-1, preferentially contained the H-type structure and were bound by immobilized UEA-I. These results demonstrate that in CHO cells the expressed H-type alpha1,2FT does not indiscriminately fucosylate terminal galactosyl residues in complex-type N-glycans, but it favors glycans containing polylactosamine and dramatically alters their length and sialylation.

ABO Blood-Group System↗
PubMed1997

Percutaneous endoscopic gastrostomy tube placement in a surgical training program.

BACKGROUND: This study examines the patterns of use of percutaneous endoscopic gastrostomy (PEG) and primary open gastrostomy (Gtube) performed in a residency training program in surgery. METHODS: A retrospective cohort study that assesses the indications and outcomes of 317 PEGs and 75 isolated Gtubes used for gastric access between 1987 and 1997. RESULTS: The demographics and risk factors of the patients receiving Gtube and PEG were comparable. The mean number of PEGs performed per resident is currently 13 per year (mean 5 over 10 years) with a 97% PEG success rate; an 88% success rate is demonstrated for placement of jejunal extensions. CONCLUSIONS: PEGs are generally preferable to Gtubes as primary procedures. Surgical residents should become competent in PEG placement by performing adequate numbers of procedures with fully trained staff.

Adult↗
PubMed1997

Community perceptions about the important signs of early melanoma.

BACKGROUND: Detecting melanoma early often relies on patient concern about a particular pigmented lesion. However, it is not clear what specific features the public views as being important. OBJECTIVE: Our purpose was to explore the importance persons place on various features of skin lesions when looking for early signs of melanoma. METHODS: This study comprised 1148 respondents (participation rate, 78%) from 60 rural communities in Queensland, Australia, who participated in a telephone interview. RESULTS: The following features were considered important and are listed in order of importance: change in the lesion (clearly identified as the most important), more than one color, uneven edges, elevation, large size (the last three of equal importance), and hairiness of the lesion. Age, sex, education, self-efficacy, perceived knowledge, and recent self-examination influenced importance levels, but having a recent skin examination by a family physician did not. CONCLUSION: To increase the skin self-examination skills of the community, guidelines may have to become more specific and all opportunities fully utilized to educate the public.

Adolescent↗
PubMed1997

The skin cancer workload in Australian general practice.

OBJECTIVE: Skin cancer is common in Australia. It is managed in large portion within general practice, and early excision usually affords cure, therefore, it may form a much greater workload for general practitioners (GPs) than incidence figures would imply. The aim of this study was to describe the skin cancer workload in Australian general practice. METHOD: Analysis of data recorded by 495 randomly selected GPs relating to 113,468 consultations (98,796 weighted for State size), which were collected as part of a national descriptive study. Medicare and census data were used to calculate rates at which GPs were consulted for different conditions. RESULTS: Skin tumours accounted for 2,083 (1.5%) of all 145,799 problems managed in 98,796 encounters. Annual rates at which GPs were consulted were: 13/1,000 people for 'malignant' tumours of the skin; 23/1,000 for 'naevus/mole; and 13/1,000 for 'other benign' lesions. The rates of diagnoses of 'malignant skin neoplasms' increased with age to a maximum among women and men aged 65 years or more of > 80/1,000 and > 100/1,000, respectively. For 'naevus/mole' the rates of maximum diagnoses were 40/1,000 for women and 351/1,000 for men aged 15-24 years. There was no sex difference for the maximal rate (15/1,000) among the 45-64 age groups for 'other benign skin lesions'. The main form of management was procedural for malignant skin lesions (90% of consultations) and naevi/moles (50%). Referral to specialist services was most common during consultations for malignant disease (22% of consultations), in comparison to naevi/moles (15%) and other benign skin neoplasms (9%). Procedures (cryotherapy, diathermy and excision) and referrals were more common for malignant lesions and naevi/moles. CONCLUSIONS: There were important differences in age distribution for rates of management of benign and malignant skin tumours and naevi. Skin tumours usually were managed in conjunction with other problems. Most were managed procedurally. Only a minority were referred. Skin cancer represents a greater workload for Australian GPs than suggested by previous incidence reports.

Adolescent↗
PubMed1996

Molecular cloning and characterization of CFT1, a developmentally regulated avian alpha(1,3)-fucosyltransferase gene.

Although coordinate expression of carbohydrate epitopes during development is well described, mechanisms which regulate this expression remain largely unknown. In this study we demonstrate that developing chicken B cells express the LewisX terminal oligosaccharide structure in a stage-specific manner. To examine regulation of this expression, we have cloned and expressed the chicken alpha(1,3)-fucosyltransferase gene involved in LewisX biosynthesis, naming it chicken fucosyltransferase 1 (CFT1). CFT1 is characterized by a single long open reading frame of 356 amino acids encoding a type II transmembrane glycoprotein. The domain structure and predicted amino acid sequence are highly conserved between CFT1 and mammalian FucTIV genes (52.8% and 46.3% identity to mouse and human respectively). In vitro CFT1 fucosyltransferase activity utilizes LacNAc > 3'sialyl-LacNAc acceptors with almost no utilization of other neutral type II (lactose, 2-fucosyllactose), or type I (lacto-N-biose I) acceptors. CFT1-transfected cells make cell surface LewisX (COS-7) and LewisX + VIM-2 structures (Chinese hamster ovary). CFT1 gene expression is tissue-specific and includes embryonic thymus and bursa. Furthermore, expression of the CFT1 gene and cell surface LewisX structures are closely linked during B cell development. These findings reveal the evolutionary conservation between nonmammalian and mammalian alpha(1,3)-fucosyltransferase genes and demonstrate a role for fucosyltransferase gene regulation in the developmental expression of oligosaccharide structures.

Amino Acid Sequence↗
PubMed1996

Adolescents' experiences of smoking cessation.

Recent prevalence rates show that by Year 10 (ages 14-16 years), 15% of students are smoking each day. As the majority of young people do not smoke, schools have traditionally provided an emphasis on prevention. However, the prevalence of daily smoking increases from 15 to 31% across the last 3 years of secondary school, suggesting a need for cessation programs. Therefore, a study of smoking cessation among students was conducted with 2877 Year 10 students in Queensland, Australia. Results of the survey showed that students (i) moderately under-estimated the number of smoking peers who had tried to stop smoking (perceived as 42%, reported as 55%), and (ii) over-estimated the success their smoking peers have (perceived as 29%, reported as 13.6%). The majority of adolescents (57.5%) reported that they had done something to influence a student not to smoke in the last 12 months, including 29% of the smokers. Among those who were current smokers, 64% wanted to stop smoking and 55% had tried to stop in the past year. Withdrawal symptoms were frequently reported among adolescent smokers and more males than females reported being stressed and depressed as a result of their efforts to quit. Intention to quit in the next year was associated with high confidence in ability to quit. These issues deserve attention in prevention programs and the development of age appropriate cessation material for adolescents should have high priority.

Adolescent↗
PubMed1996

An important role for the alpha 1,3 fucosyltransferase, FucT-VII, in leukocyte adhesion to E-selectin.

E-selectin is an adhesion molecule expressed on the surface of activated endothelial cells, which has been shown to be important in the initial steps of leukocyte extravasation into inflamed tissues. E-selectin binds neutrophils, monocytes, eosinophils, basophils, natural killer (NK) cells, and subsets of lymphocytes, although the precise ligand(s) on these cells have not been identified. Several studies have proposed certain carbohydrate structures, including sLex and related structures, as E-selectin ligands. In contrast to these studies, we report here the identification of several human B cell lines that exhibit binding to E-selectin without expression of any of the previously identified E-selectin binding carbohydrate epitopes. The unique carbohydrate phenotype of these B cell lines suggests that they may express a novel, sialylated carbohydrate structure(s) that binds to E-selectin. To investigate the enzymatic basis of this novel form of E-selectin binding, we examined the expression of the two principal leukocyte alpha 1,3 fucosyltransferases, FucT-IV and FucT-VII, in a panel of human hematopoietic cell lines. FucT-VII was expressed in all E-selectin binding cell lines except one, whereas FucT-IV was expressed by nearly all cell lines, regardless of their ability to bind E-selectin. In addition, transfection of cells with cDNA encoding FucT-VII conferred E-selectin binding ability. Taken together, these data suggest that, regardless of surface carbohydrate phenotype, E-selectin binding ability is determined largely by expression of FucT-VII.

B-Lymphocytes↗
PubMed1996

Detection of N-acetylgalactosaminyltransferase mRNA which determines expression of Sda blood group carbohydrate structure in human gastrointestinal mucosa and cancer.

The Sda blood group carbohydrate structure, GalNAcbeta1-4[NeuAcalpha2-3]Galbeta1-4GlcNAc-R, is expressed on glycolipid and glycoprotein in human gastrointestinal mucosa. The expression of the Sda determinant dramatically decreases in cancer tissue. The activity of the beta1,4N-acetylgalactosaminyltransferase (Sda-GalNAcT), which transfers GalNAc to NeuAcalpha2-3Galbeta1-4Glc(NAc)-R, correlates with the expression of the Sda immuno-epitope. From the total RNA fraction of human gastric mucosa, we have amplified a cDNA segment by reverse-transcription-polymerase-chain reaction (RT-PCR), using primers designed according to the cDNA sequence of a murine beta1,4GalNAcT which synthesizes the Sda determinant. An RT-PCR product of 390 bp shared 85% nucleotide identity with the murine Sda-related beta1,4GalNAcT. This RT-PCR product hybridized to a transcript in mRNA prepared from human gastric mucosa. In RT-PCR using specific primers to this PCR product, Sda-GalNAcT mRNA was detected in all samples of normal stomach and small intestine examined and the majority of normal colonic specimens. Six out of nine cases of gastric cancer, and 9 out of 13 cases of colonic cancer failed to produce the target DNA. These results correlate with the beta1,4GalNAcT activity measured in the same samples. In conclusion, a segment of the cDNA for betal,4GalNAcT which determines expression of the Sda carbohydrate structure was obtained, and reduced transcription of this beta 1,4GalNAcT resulted in the disappearance of the Sda epitope in gastrointestinal cancer.

Animals↗
PubMed1996

The alpha(1,3)fucosyltransferase Fuc-TVII controls leukocyte trafficking through an essential role in L-, E-, and P-selectin ligand biosynthesis.

alpha(1,3)Fucosylated oligosaccharides represent components of leukocyte counterreceptors for E- and P-selectins and of L-selectin ligands expressed by lymph node high endothelial venules (HEV). The identity of the alpha(1,3)fucosyltransferase(s) required for their expression has been uncertain, as has a requirement for alpha(1,3)fucosylation in HEV L-selectin ligand activity. We demonstrate here that mice deficient in alpha(1,3) fucosyltransferase Fuc-TVII exhibit a leukocyte adhesion deficiency characterized by absent leukocyte E- and P-selectin ligand activity and deficient HEV L-selectin ligand activity. Selectin ligand deficiency is distinguished by blood leukocytosis, impaired leukocyte extravasation in inflammation, and faulty lymphocyte homing. These observations demonstrate an essential role for Fuc-TVII in E-, P-, and L-selectin ligand biosynthesis and imply that this locus can control leukocyte trafficking in health and disease.

Animals↗
PubMed1996

Expression of the alpha(1,3)fucosyltransferase Fuc-TVII in lymphoid aggregate high endothelial venules correlates with expression of L-selectin ligands.

Lymphocyte homing to lymph nodes and Peyer's patches is mediated, in part, by adhesive interactions between L-selectin expressed by lymphocytes and L-selectin ligands displayed at the surface of the cuboidal endothelial cells lining the post-capillary venules within lymphoid aggregates. Candidate terminal oligosaccharide structures thought to be essential for effective L-selectin ligand activity include a sulfated derivative of the sialyl Lewis x tetrasaccharide. Cell type-specific synthesis of this oligosaccharide is presumed to require one or more alpha(1,3)fucosyltransferases, operating upon common 3'-sialylated and/or sulfated N-acetyllactosamine-type precursors. The identity of the alpha(1,3)fucosyltransferase(s) expressed in cells that bear L-selectin ligands has not been defined. We report here the molecular cloning and characterization of a murine alpha(1,3)fucosyltransferase locus whose expression pattern correlates with expression of high affinity ligands for L-selectin. In situ hybridization and immunohistochemical analyses demonstrate that this cDNA and its cognate alpha(1,3)fucosyltransferase are expressed in endothelial cells lining the high endothelial venules of peripheral lymph nodes, mesenteric lymph nodes, and Peyer's patches. These expression patterns correlate precisely with the expression pattern of L-selectin ligands identified with a chimeric L-selectin/IgM immunohistochemical probe and by the high endothelial venule-reactive monoclonal antibody MECA-79. Transcripts corresponding to this cDNA are also detected in isolated bone marrow cells, a source rich in the surface-localized ligands for E- and P-selectins. Sequence and functional analyses indicate that this murine enzyme corresponds to the human Fuc-TVII locus. These observations suggest that Fuc-TVII participates in the generation of alpha(1,3)fucosylated ligands for L-selectin and provide further evidence for a role for this enzyme in E- and P-selectin ligand expression in leukocytes.

Amino Acid Sequence↗
PubMed1996

The fucosyltransferase FucT-VII regulates E-selectin ligand synthesis in human T cells.

Selectin-ligands on T cells contribute to the recruitment of circulating cells into chronic inflammatory lesions in the skin and elsewhere. This report provides the first evidence that a single fucosyltransferase, termed FucT-VII, controls the synthesis of E-selectin ligands in human T-lymphoblasts. The FucT-IV transferase (the ELFT enzyme), in contrast constructs lower avidity E-selectin ligands and requires enzyme levels found only in myeloid cells. Treatment of Jurkat cells with phorbol myristate acetate increased the expression of sialylated Lewis(x)-related sLe(x)related epitopes and induced the synthesis of E-selectin ligands functional at physiologic levels of linear shear-stress. Northern analysis revealed a parallel increase in the steady-state levels FucT-VII mRNA, but there were no increases in the two other leukocyte-associated fucosyltransferases (FucT-IV and VI). The stable transfection of the FucT-VII gene into Jurkat cells induced high levels of the sLe(x)-related epitopes and the synthesis of E-selectin ligands which equal or exceeded the avidity of those on circulating lymphocytes. The growth of T-lymphoblasts under conditions which induced expression of the sLe(x,a) epitopes increased the level of FucT-VII mRNA, the synthesis of sialylated-Lewis(x) structures by cell-free extracts and the synthesis of E-selectin ligands equal in avidity to those on FucT-VII transfectants. In contrast, neither the mRNA levels nor activities of the FucT-IV and VI enzymes increased in association with E-selectin ligand synthesis in T-lymphoblasts. Myeloid cell lines, unlike lymphoblasts, expressed high levels of both the FucT-VII and IV enzymes in conjunction with E-selectin ligands raising the possibility that both enzymes contributed to ligand synthesis. FucT-IV transfected Jurkat cells synthesized low avidity ligands for E-selectin but only in association with CDw65 (VIM-2) carbohydrate epitope. Only blood neutrophils and myeloid cell lines expressed this epitope at the levels associated with E-ligand synthesis in the transfectants. In contrast, native Jurkat cells, blood monocytes, blood lymphocytes, and cultured T-lymphoblasts expressed low levels or none. We conclude that FucT-VII is a principal regulator of E-selectin ligand synthesis in human T-lymphoblasts while both FucT-VII and FucT-IV may direct ligand synthesis in some myeloid cells.

Antigens, CD↗
PubMed1996

Sialylated, fucosylated ligands for L-selectin expressed on leukocytes mediate tethering and rolling adhesions in physiologic flow conditions.

Interaction of leukocytes in flow with adherent leukocytes may contribute to their accumulation at sites of inflammation. Using L-selectin immobilized in a flow chamber, a model system that mimics presentation of L-selectin by adherent leukocytes, we characterize ligands for L-selectin on leukocytes and show that they mediate tethering and rolling in shear flow. We demonstrate the presence of L-selectin ligands on granulocytes, monocytes, and myeloid and lymphoid cell lines, and not on peripheral blood T lymphocytes. These ligands are calcium dependent, sensitive to protease and neuraminidase, and structurally distinct from previously described ligands for L-selectin on high endothelial venules (HEV). Differential sensitivity to O-sialo-glycoprotease provides evidence for ligand activity on both mucin-like and nonmucin-like structures. Transfection with fucosyltransferase induces expression of functional L-selectin ligands on both a lymphoid cell line and a nonhematopoietic cell line. L-selectin presented on adherent cells is also capable of supporting tethering and rolling interactions in physiologic shear flow. L-selectin ligands on leukocytes may be important in promoting leukocyte-leukocyte and subsequent leukocyte endothelial interactions in vivo, thereby enhancing leukocyte localization at sites of inflammation.

Animals↗
PubMed1996

A second nonsecretor allele of the blood group alpha(1,2)fucosyl-transferase gene (FUT2).

While screening Le(a+b+)Polynesian DNA samples for a candidate Se(w) allele, a point mutation (C571-->T) resulting in a new stop codon (Arg191-->stop) in the alpha(1,2)fucosyltransferase gene (FUT2) was identified. This point mutation resulted in the gaining of a new restriction enzyme cleavage site (DdeI), which allowed restriction enzyme cleavage screening of 40 selected Polynesians and 42 random Caucasians. The nonsecretor phenotype in two of the three nonsecretor Polynesians analyzed was due to homozygosity for the 'new' mutation, whereas the third Polynesian nonsecretor (with Caucasian ancestors) was due to homozygosity of the 'old' (Trp143-->stop) mutation. The nonsecretor phenotype in all Caucasians analyzed was a consequence of homozygosity for the 'old' mutation. Both the new and the old nonsecretor mutations were identified in the heterozygous state in some secretor-positive Polynesians, while only the old mutation was found in the heterozygous state in Caucasians of the same phenotype.

Alleles↗
PubMed1996

Effect of a public awareness campaign on the appropriateness of patient-initiated skin examination in general practice.

The aim of the study was to describe the appropriateness of patient-initiated skin examinations, and assess whether an awareness program leads to a greater proportion of inappropriate patient-initiated skin examinations. General practitioners (n = 27, response rate 71 per cent) from a regional town in Queensland recorded details of consultations involving a skin examination over a five-week period straddling the 1991 National Skin Cancer Awareness Week. The outcome measure was the clinical impression (benign, suspicious or malignant) of the most serious skin lesion presented by each general practice patient (n = 1183). Thirty-six per cent of patient-presented lesions were clinically suspicious or malignant. Lesions were more likely to be clinically suspicious or malignant if they were presented as the primary reason for the consultation (odds ratio OR = 1,219.95 per cent confidence interval (CI) 1.01 to 1.48); if the patient was aged over 35 years (OR = 5.594, CI 1.08 to 7.66); or male (OR = 1.634, CI 1.35 to 2.00). Following a public skin cancer awareness campaign, there was a slight nonsignificant decrease (OR 0.938, CI 0.91 or 1.25) in the proportion of clinically suspicious and malignant lesions detected. An increase in the number of skin examinations following an awareness campaign did not result in an increase in the proportion of inappropriate skin examinations. Patient-initiated skin examinations have an important role to play in the early detection of skin cancer.

Adult↗
PubMed1996

Barriers to health promotion activities in public hospitals.

Despite the central role hospitals have in the health care system, relatively few health promotion activities are conducted in Australian public hospitals. This study investigated the types of obstacles that were perceived to inhibit health promotion activities in hospitals. A questionnaire for self-completion was sent to medical superintendents in all public hospitals in Queensland and 112 questionnaires were returned (92.6 per cent response rate). The results indicated that lack of finance, lack of interest by relevant others, and needs (for appropriate programs, training and patient receptivity) were the barriers reported by superintendents. The barriers of 'interest' and 'needs' were related to a lack of written policies in some areas, but not directly to levels of other health promotion activities being conducted in the hospitals. Success in facilitating health promotion programs in hospitals will need to include a change in the environment, in particular the views of medical superintendents. The combination of attitude change and the availability of a motivated person (such as a health promotion officer) to lead the activities may be needed in order to produce an increase in the level of health promotion in public hospitals.

Chi-Square Distribution↗