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Biomedical subjects

J Rowe

Publications and source records attributed to J Rowe.

At least 145 records · Page 8Linked to original sources
PubMed1976

Purification, subunit structure and partial amino-acid sequence of anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferase from the enteric bacterium Serratia marcescens.

The enzyme anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferase from Serratia marcescens was purified to apparent homogeneity. The purification procedure included ammonium sulfate precipitation, DEAE-cellulose chromatography, Sephadex gel filtration and hydroxyapatite chromatography. The molecular weight of the native protein as determined on a calibrated Sephadex G-200 column was 45000. Dodecylsulfate-polyacrylamide gel electrophoresis in the presence of reducing agent revealed a subunit molecular weight of 43000 +/- 900, suggesting that the enzyme exists as a monomer. The sequence of the amino-terminal 38 residues revealed that three amino amino acids, glutamine (six residues), glutamic acid (five residues) and serine (five residues) comprised 42% of the sequence composition.

Amino Acid Sequence↗
PubMed1976

Immunosuppressive activity of submaxillary gland extracts of the mouse. I. Effect on antibody formation in response to sheep red blood cells.

Aqueous extracts of mouse submaxillary glands yield six peaks on Sephadex G-75 columns, each containing several molecular species. Two of these fractions (III and IV) have a profound effect on the immune response. When given a day before immunization with sheep erythrocytes, the number of antibody-producing cells is reduced ten-fold or more, and the switch from IgM to IgG is virtually absent. Administration two days before or on the day of immunization results in about 50% depression; outside this range there is no effect. The dose-response curve is of sigmoid shape, with the median at about 0.5 mg of fraction III/40 g mouse, reaching an asymptote after doses of greater than or equal to 5 mg at about 5% of the response of untreated mice. Depression of the primary response does not prevent the development of immunological memory: the secondary response is typical in the early and predominant appearance of IgG-producing cells, although their numbers are somewhat lower than in the controls which received no treatment before primary immunization. Treatment on the day before boosting abrogates the secondary response. The immunotranquilizer from mouse submaxillary glands acts equally well on syngeneic and allogeneic recipients, affecting the earliest stage of the immune response. The results are compatible with the induction of a temporary block in the development of helper T cells.

Animals↗
PubMedDate not supplied

Nosocomial sepsis in neonates with single lumen vascular catheters.

Catheter-related sepsis is commonly encountered in the neonatal intensive care unit. We retrospectively studied infants with vascular catheters at 2 NICUs. Data were obtained from the computerised admission records available at both the hospitals. Our aims were to describe the clinical and microbial profile of nosocomial sepsis in infants with vascular catheters [umbilical artery (UA), umbilical venous (UV), central venous Broviac (CV), percutaneously placed central venous (PC), peripheral artery (PA)], and to determine the association between catheter type, duration and sepsis in a subset of the population. Nosocomial sepsis (positive blood culture after the 3rd postnatal day) occurred in 217 of 2091 (10.4%) infants. Infected infants, in contrast to non-infected, had a significantly (P < 0.001) greater number of multiple catheters (2.3 vs 1.4) had lower birth weights (1.2 vs 2.1 kg), were younger (28 vs 33 weeks) and had lower 1 and 5 minute Apgar scores (4.3 and 6.7 vs 5.5 and 7.4). The most common organism was coagulase negative Staphylococcus. In a subset population as analyses revealed, longer duration of UA use was associated with higher infection rates [13.6% with UA use for > or = 8 days vs 1.3% for < or = 7 days (P < 0.0001)]. PC use had a lower rate of sepsis than CV use (5.1% vs 15.2%; P < 0.05). Use of intravascular catheters should be balanced between the need for vascular access and the risk of sepsis.

Catheterization↗
PubMedDate not supplied

Spectrum of osteoblastic differentiation in new cell lines derived from spontaneous murine osteosarcomas.

Cell lines were established from three spontaneous osteosarcoma and one fibrosarcoma of aging mice. They were studied for tumorigenicity, osteoblastic features, and other in vitro cellular characteristics, by a combination of histological, morphological, biochemical, and molecular approaches. It was found that all cell lines formed tumors in vivo, whereas in vitro, only the fibrosarcoma-derived cell line grew efficiently in soft agar. Three out of the four cell lines produced mouse endogenous retroviruses, but none were classical sarcoma viruses. Type I collagen was expressed by all the cell lines, as was another extracellular matrix protein, osteonectin. The osteosarcoma-derived cell lines, however, exhibited different degrees of osteogenic differentiation. Only one line (OSA), and its clonal subline (1G11), consistently gave rise to mineralized tumors after transplantation into syngeneic mice, and these cells expressed high levels of alkaline phosphatase and bone-specific osteocalcin mRNA in vitro. Expression of these biochemical markers of osteoblasts occurred to a lesser extent in a second line (OSC) and was undetectable in the third line (OSB). The clonal 1G11 cell line exhibits the phenotype of a fully mature osteoblast and thus may serve as a particularly useful model for studies of bone cell function and regulation. Studies of cells which display a wide spectrum of osteogenic potential may further our understanding of the mechanisms involved in bone cell differentiation and tumorigenicity.

Alkaline Phosphatase↗
PubMedDate not supplied

An immunoepidemiological approach to asthma: identification of in-vitro T-cell response patterns associated with different wheezing phenotypes in children.

BACKGROUND: Increasing evidence suggests that patterns of T-cell immunity to inhalant allergens in genetically diverse human populations are more heterogeneous than previously assumed, and that covert differences in expression patterns might underlie variations in airway disease phenotypes. We tested this proposition in a community sample of children. METHODS: We analysed data from 172 individuals who had been recruited antenatally to a longitudinal birth cohort study. Of the 194 birth cohort participants, data from the 147 probands (age range 8.6-13.5 years) who consented to blood collection were included along with data from 25 consenting siblings (mean age 11 years [range 7.4-17.4]). We ascertained clinical phenotypes related to asthma and allergy. We measured T-cell responses to allergens and mitogens, together with blood eosinophils and IgE/IgG antibodies, and assessed associations between these indices and clinical phenotypes. FINDINGS: Atopy was associated with allergen-specific T-helper (Th)2 responses dominated by interleukin 4, interleukin 5, interleukin 9, interleukin 13, whereas interleukin 10, tumour necrosis factor alpha, and interferon gamma responses were common to both atopics and non-atopics. The wheal size from skin prick with allergen was positively associated with in-vitro interleukin 5 and interferon gamma responses, and negatively associated with interleukin 10. Asthma, especially in atopics, was strongly associated with eosinophilia/interleukin 5, and bronchial hyper-responsiveness (BHR) was associated with eosinophilia plus polyclonal interferon gamma production. BHR in non-atopics was associated with elevated allergen-specific and polyclonal interleukin 10 production. INTERPRETATION: Parallel immunological and clinical profiling of children identified distinctive immune response patterns related to asthma and wheeze compared with BHR, in atopics non-atopics. Immunological hyper-responsiveness, including within the Th1 cytokine compartment, is identified as a hallmark of BHR. RELEVANCE TO PRACTICE: These findings highlight the heterogeneity of immune response patterns in asthmatic children, including those with seemingly homogeneous Th2-driven atopic asthma. Further elucidation of the covert relationships between wheezing phenotypes and underlying immunophenotypes in this age group will potentially lead to more effective treatments for what is an unexpectedly heterogeneous collection of disease subtypes.

Adolescent↗