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Biomedical subjects

R Hull

Publications and source records attributed to R Hull.

At least 127 records · Page 7Linked to original sources
PubMed1990

Use of plasmid analysis to determine the source of bacterial invasion of the urinary tract.

Gram negative colonisation and infection of the urinary tract is a well recognised complication of the neuropathic bladder caused by spinal cord injury (SCI). K. pneumoniae accounts for one third of all urinary tract infections in hospitalised SCI patients. Plasmid analysis has been shown to reliably fingerprint bacterial strains, particularly K. pneumoniae, so that growth from two separate locations in or on the body can be accurately analysed as to migration from a reservoir to a target location. Eighty seven hospitalised SCI patients on intermittent catheterisation for a total of 586 patient-weeks were studied. Twice weekly catheterised urine specimens and once weekly rectal swab cultures were taken from each patient. Thirty seven patients experienced at least one clinically significant (colony count greater than 10,000/mL) urinary tract colonisation caused by K. pneumoniae, representing 66 total colonisations. Further analysis of 31 of these 37 patients revealed: K. pneumoniae in all of their stool cultures (p less than 0.05) and the identical strain of K. pneumoniae in the urine as well as the stool in 72% of the 66 colonisations (p less than 0.05). Analysis of 14 patients without K. pneumoniae urinary colonisations showed absence of faecal K. pneumoniae in 3, and predominant growth in only 4. In 22 of the 37 patients, multiple K. pneumoniae urinary colonisations were noted, representing 27 pairs of colonisation. Fifteen of the pairs were found to be relapsing (caused by two identical bacterial strains), and 12 were recurrent (caused by two different bacterial strains). Thirteen of the 15 relapsing pairs also had identical urine and stool K. pneumonia strains (p less than 0.05). All colonisations were treated with appropriate antibiotics based on culture and sensitivity reports. Fourteen of the 15 relapsing colonisation pairs have identical antibiograms (p less than 0.05), while all 12 of the recurrent colonisation pairs had different antibiograms (p less than 0.05). The differences noted on sensitivity patterns (antibiograms) correlated with differences among strains of K. pneumoniae based upon plasmid analysis. Treatment of bacteriuria did not affect the nature of repeated colonisations regardless of the antibiotic chosen, the route of administration or the duration of treatment.

Adolescent↗
PubMed1990

Frequency and organization of pap homologous DNA in relation to clinical origin of uropathogenic Escherichia coli.

The pap operon encodes the gal alpha 1-4gal beta specific adhesins of Escherichia coli. The presence and organization of pap homologous DNA was determined using two probes specific for pap in 217 uropathogenic E. coli samples by dot blot and Southern blot analysis. The frequency of pap homologous DNA was 76% in pyelonephritis, 69% in cystitis, and 52% in an asymptomatic bacteriuria group. Further, the gal alpha 1-4gal beta binding phenotype among the pap-positive strains was expressed more often in acute pyelonephritis (91%) than the cystitis (60%) or asymptomatic bacteriuria (52%) strains. This was explained in part by difference in organization of pap homologous DNA between the genotypically positive pyelonephritis and asymptomatic bacteriuria strains. The pyelonephritis isolates contained three copies of pap significantly more often than the asymptomatic bacteriuria strains, and the pyelonephritogenic O-antigen types had a general increase in pap copy number. The difference in expression of gal alpha 1-4gal beta adhesins between pyelonephritis and asymptomatic bacteriuria isolates was thus not only a function of the frequency of pap homologous DNA but also of phenotypic expression among genotypically pap-positive strains.

Acute Disease↗
PubMed1990

Predicting the daily prothrombin time response to warfarin.

Our objective was to evaluate the effectiveness of a computer program to predict daily prothrombin time (PT) response to warfarin therapy using prospectively collected data. The program's predictive performance (precision) and accuracy (bias) were evaluated using fraction mean absolute error and fraction mean error, respectively. We analyzed data from 40 patients using from zero to nine PT feedbacks. The fraction mean absolute error varied from 0.058 to 0.13. The program utilized a pharmacokinetic/pharmacodynamic Bayesian forecasting system to predict prothrombin response.

Aged↗
PubMed1990

The Dr hemagglutinin, afimbrial adhesins AFA-I and AFA-III, and F1845 fimbriae of uropathogenic and diarrhea-associated Escherichia coli belong to a family of hemagglutinins with Dr receptor recognition.

The receptor specificities of four Escherichia coli cloned hemagglutinins, AFA-I, AFA-III, F1845 fimbriae, and the Dr hemagglutinin were studied. Evidence is provided that all four hemagglutinins recognize as their receptor the Dr blood group antigen. However, results of experiments using enzyme-treated erythrocytes and monoclonal antibodies indicate that the four adhesins recognize different epitopes on the Dr antigen and thus constitute a family of Dr receptor-recognizing bacterial adhesins. Furthermore, the same results suggest that the Dr antigen itself may be divided into subcomponents on the basis of bacterial adhesins.

Adhesins, Escherichia coli↗
PubMed1989

The current status and future directions of impedance cardiography in ICU.

Impedance cardiography has not achieved popularity in the Intensive Care Unit (ICU) to date probably because of the limitations in technique and interpretation associated with the altered physiology of critically ill patients, and also because of interference from other machinery in the ICU. The current climate of questioning the existing technology for bedside cardiovascular assessment however spurs the need to evaluate impedance cardiography as a noninvasive alternative. Validation in noncritically ill patients is good when compared to other technologies (e.g., thermodilution, Fick, dye dilution (r greater than 0.9)). Reliability is good with a coefficient of variation in an ICU population of 8.9%, (compared to 18.6% for thermodilution). It has also shown promise in detecting the clinically significant changes of central intravascular volume. Impedance cardiography appears to be useful for measurement of stroke volume (SV) and ejection fraction (EF). From these, left ventricular end-diastolic volume (VED) can be calculated, probably a more reliable estimate of left ventricular filling than pulmonary capillary wedge pressure (PW), measured by pulmonary artery (PA) catheter. In addition, VES can be calculated and with the knowledge of left ventricular end-systolic pressure (PES) (from invasive arterial monitoring), an end-systolic pressure-volume (ES-PV) relationship can be derived. This is thought to be a measure of contractility that is independent of preload and afterload. The ultimate test in the ICU for impedance cardiography is whether clinical outcome of critically ill patients is altered by the use of this technology. Such outcome testing is essential before the true value of impedance cardiography in the management of critically ill patients can be determined.

Cardiography, Impedance↗
PubMed1989

Southern bean mosaic virus RNA remains associated with swollen virions during translation in wheat germ cell-free extracts.

L-[35S]Methionine-labeled translation complexes were prepared by incubating either swollen intact southern bean mosaic virus (SBMV) particles or unencapsidated SBMV RNA in a wheat germ extract. The complexes were analysed by sucrose gradient centrifugation and by electron microscopy and dot blot hybridization of fractions from these gradients. In these complexes, 80 S ribosomes appeared to be associated with intact or near intact particles, suggesting that SBMV particles disassemble only after their RNA has initiated translation. This is in contrast to some other isometric viruses, such as turnip yellow mosaic virus, which appear to release their RNA rapidly prior to translation.

Cell-Free System↗
PubMed1989

Binding specificities of wild-type and cloned Escherichia coli strains that recognize globo-A.

In this study we compared the specificity for the globoseries of glycolipids of Escherichia coli expressing the O-negative, A-positive (ONAP) adhesin and clones transformed with the pap-like (prs or pap-2) gene cluster. Receptor-active glycolipids were identified by the ability of radiolabeled bacteria to bind to the glycolipids on thin-layer chromatogram plates. The ONAP adhesin and pap-like clones bound with high affinity to the globo-A and Forssman glycolipids. The ONAP strains did not recognize other glycolipids of the globoseries. In contrast, the pap-like clones also showed weak binding to globotriaosylceramide and reacted weakly with Gal alpha 1----4 Gal beta-latex beads. We suggest that the pap-like and ONAP adhesins recognize an epitope shared by the globo-A and Forssman structures, e.g., terminal GalNAc alpha 1----3 bound to Gal alpha 1----4Gal beta-containing glycolipids.

Adhesins, Escherichia coli↗