Search PubMed⌕ Search

Biomedical subjects

D T Jones

Publications and source records attributed to D T Jones.

At least 163 records · Page 9Linked to original sources
PubMed1984

Vegetable consumption and blood lead concentrations.

Women resident in an area heavily contaminated by spoil from old lead mining have blood lead concentrations that are about 50% higher (p less than 0.001) than those of women living in a "control" area some distance away. Blood lead concentrations were related to the consumption of home grown produce. Those with the highest consumptions had blood lead concentrations that were 28% higher (p less than 0.001) than those of women who consumed no locally grown vegetables. Nevertheless, in the total population in the area this effect seemed likely to account for only about 5% of the population mean blood lead concentration. The data suggested that an increase in soil lead of 1000 micrograms/g is associated with an increase in blood lead of about 0.20 microM/1 (4.2 micrograms/dl).

Adult↗
PubMed1984

Comparison of patients attending general practitioner and consultant day hospitals for the elderly.

A comparative study of patients attending general practitioner and consultant day hospitals for the elderly in Clwyd is described. The general characteristics of both patient groups were similar. There were, however, differences in the types of illness represented: disorders of the nervous system, mainly strokes, comprised over one third (37 per cent) of the consultant day hospital cases; disorders of the musculoskeletal system, mainly osteoarthrosis, comprised nearly one third (29 per cent) of the general practitioner group. Over 70 per cent of patients attending both types of day hospital had been discharged within six months and most attended once or twice each week. Clinical evaluation on discharge showed that over 80 per cent of the patients in both types of hospital had shown improvement or had not further deteriorated during their period of attendance.It is concluded that day hospital care in community hospitals, supervised by general practitioners, can make an effective contribution to total health care provision for the elderly.

Activities of Daily Living↗
PubMed1983

The neutron sensitivity of a Geiger-Müller counter between 0.5 and 8 MeV.

Geiger-Müller counters are often used in mixed-field dosimetry to determine the photon dose fraction. For accurate dose specification, their neutron sensitivities must be known. The pulsed beam time-of-flight method was used to determine the neutron sensitivities of an energy-compensated type ZP1320/PTFE Geiger-Müller counter in the 0.5-8-MeV region. The flux of monoenergetic neutrons from the T(p,n)3He and D(d,n)3He reactions, which were used in these measurements, was determined from time-of-flight spectra with an NE213 scintillation counter of known efficiency.

Calibration↗
PubMed1983

Sporulation of Clostridium acetobutylicum P262 in a Defined Medium.

A defined minimal sporulation medium for Clostridium acetobutylicum P262, which produces high levels of solvents, is described. The overall sporulation sequence was similar to that of other endospore-forming bacteria. However, we observed a presporulation stage, during which swollen phase-bright cells which contained large amounts of granulose formed. During sporulation, the initiation of spore coat formation occurred before the onset of cortex formation. Other Clostridium strains tested showed marked variations in ability to grow and sporulate in various minimal media.

Journal Article↗
PubMed1982

Asthma in seven year old children: a report from the Dunedin Multidisciplinary Child Development Study.

The prevalence of asthma between birth and seven years was determined by questionnaire in 875 children as part of the Dunedin Multidisciplinary Child Development Study. From the combinations of asthma and/or wheezing reported in association with bronchitis, hayfever, eczema and allergies, a diagnosis of certain or probable asthma was made in 12.6 percent of these children. A further 22.6 percent admitted to wheezing, but a diagnosis of asthma could not be made with any certainty. Bronchitis was reported frequently, usually associated with wheezing. Children with more obvious asthma showed a male preponderance and significant differences in body build and school attendance compared with asymptomatic children.

Absenteeism↗
PubMed1982

Absolute measurement of the neutron sensitivity of a ZP1320 geiger-Müller counter using the associated-particle technique.

Because of their low neutron sensitivity Geiger-Müller counters are often used in mixed-field dosimetry to determine the photon dose fraction. The associated-particle technique has been used to determine absolutely the neutron sensitivity of an energy-compensated ZP1320 Geiger-Müller counter at 3 MeV. The measurement is consistent with previous measurements using this type of counter.

Neutrons↗
PubMed1982

Solvent Production and Morphological Changes in Clostridium acetobutylicum.

The morphological and cytological changes which occurred in Clostridium acetobutylicum P262 during the production of acetone, butanol, and ethanol in an industrial fermentation medium were identified and correlated with the growth and physiological changes. The swollen, cigar-shaped clostridial forms were involved in the conversion of acids to neutral solvents, and there was a correlation between the number of clostridial forms and the production of solvents. Sporulation mutants which were unable to form clostridial stages (cls mutants) did not produce solvents. Oligosporogenous mutants which showed reduced clostridial stage formation produced intermediate levels of solvents. Sporulation mutants blocked after the clostridial stage, which were unable to form mature spores (spo mutants), produced normal levels of solvents.

Journal Article↗
PubMed1982

Autolytic Activity and Butanol Tolerance of Clostridium acetobutylicum.

The effects of acetone and butanol on the growth of vegetative cells and the stability of swollen-phase bright-stationary-phase cells (clostridial forms) of Clostridium acetobutylicum P262 and an autolytic deficient mutant (lyt-1) were investigated. There was little difference in the sensitivity of strain P262 and the lyt-1 mutant vegetative cells and clostridial forms to acetone. The stability of the different morphological stages was unaffected by acetone concentrations far in excess of those encountered in factory fermentations. Butanol concentrations between 7 and 16 g/liter, which are within the range obtained in industrial fermentations, increased the degeneration of strain P262 clostridial forms but had no effect on the stability of lyt-1 clostridial forms which never underwent autolysis. Vegetative cells of the lyt-1 mutant were able to grow in higher concentrations of butanol than strain P262 vegetative cells. It was concluded that there is a relationship between butanol tolerance and autolytic activity.

Journal Article↗
PubMed1982

UV light induction of proteins in Bacteroides fragilis under anaerobic conditions.

Far-UV irradiation of Bacteroides fragilis cells under anaerobic conditions resulted in the induction of a new 95,000-molecular-weight protein and the increased synthesis of two proteins with molecular weights of 90,000 and 70,000. The latter two proteins were synthesized in small amounts in unirradiated cells. The induction of a 37,000- to 40,000-molecular-weight protein was not observed in irradiated B. fragilis cells. Caffeine, which affected the survival of irradiated B. fragilis cells and reduced host cell-mediated UV reactivation, specifically inhibited the induction of the 95,000-, 90,000-, and 70,000-molecular-weight proteins. Sodium arsenite did not affect the induction of the three inducible proteins or the survival of irradiated B. fragilis cells.

Arsenic↗
PubMed1981

Inhibition of ribonucleic acid polymerase by a bacteriocin from Bacteroides fragilis.

The Bacteroides fragilis bacteriocin which inhibits ribonucleic acid (RNA) polymerase activity had a narrow activity spectrum in vivo and only inhibited the growth of certain B. fragilis strains. In vitro the bacteriocin was not specific and inhibited RNA polymerases from widely diverse bacterial genera. RNA polymerases from rifampin-resistant strains of Bacteroides thetaiotaomicron and Clostridium acetobutylicum were resistant to the bacteriocin in vitro. Purified bacteriocin bound to partially purified RNA polymerase, and both proteins were cosedimented in a glycerol gradient. In the RNA polymerase reaction, the bacteriocin acted as a competitive inhibitor for adenosine, cytidine, and uridine 5'-triphosphates and as a noncompetitive inhibitor for guanosine 5'-triphosphate. The bacteriocin did not inhibit RNA polymerase from chicken embryos.

Bacteriocins↗
PubMed1981

Purification and Characterization of an Autolysin from Clostridium acetobutylicum.

A proteinaceous substance with antibiotic-like activity, resembling that of a bacteriocin, was isolated from an industrial-scale acetone-butanol fermentation of Clostridium acetobutylicum. The substance, purified by acetone precipitation, diethylaminoethyl cellulose chromatography, and polyacrylamide gel electrophoresis, was characterized as a glycoprotein with a molecular weight of 28,000. The glycoprotein was partially inactivated by certain protease enzymes. It had no effect on deoxyribonucleic acid, ribonucleic acid, or protein synthesis, and it did not result in the loss of intracellular adenosine triphosphate. The glycoprotein lysed sodium dodecyl sulfate-treated cells and cell wall preparations, and therefore it is referred to as an autolysin. The autolysin gene appeared to be chromosomal since plasmid deoxyribonucleic acid was not detected in the C. acetobutylicum strain.

Journal Article↗