Successful in-vitro cultivation of Borrelia recurrentis.
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Adult↗
Biomedical subjects
D J Wright
Publications and source records attributed to D J Wright.
Immunomagnetic separation as a sensitive method for isolating Escherichia coli O157 from food samples.
Minced beef samples inoculated with Escherichia coli O157 were cultured in buffered peptone water supplemented with vancomycin, cefsulodin and cefixime (BPW-VCC) and subcultured to cefixime tellurite sorbitol MacConkey (CT-SMAC) agar both directly and after immunomagnetic separation (IMS) of the organism with magnetic beads coated with an antibody against E. coli O157 (Dynabeads anti-E. coli O157, Dynal, Oslo). E. coli O157 was recovered from initial inocula of 200 organisms/g by direct subculture and 2 organisms/g by IMS. Twelve strains of E. coli O157 of different combinations of phage type, H antigen and toxin genotype were all recovered from initial inocula of two organisms/g by IMS. Non-specific binding of other organisms to the magnetic beads could be reduced by washing of the beads in PBS with Tween-20 0.002-0.005% E. coli O157 was not bound by magnetic coated with an unrelated antibody. During investigation of a dairy herd that was possibly linked to a small outbreak of infection with E. coli O157, the organism was isolated from 2 of 279 forestream milk samples from individual cattle; both isolates were made only by the IMS technique. IMS is rapid, technically simple, and a specific method for isolation of E. coli O157 and will be useful in epidemiological studies.
Animals↗
Demographic characteristics and prevalence of serologic markers among donors who use the confidential unit exclusion process: the Retrovirus Epidemiology Donor Study.
BACKGROUND: Most blood centers utilize a confidential unit exclusion (CUE) process, intended to reduce the risk of transfusion-associated infectious diseases by allowing high-risk donors confidentially to exclude their blood from use for transfusion. The effectiveness of this method remains controversial. STUDY DESIGN AND METHODS: Confirmatory or supplemental test results for antibodies to human immunodeficiency virus, human T-lymphotropic virus type I, and hepatitis C virus, as well as hepatitis B surface antigen and syphilis and screening test results for antibodies to hepatitis B core (antigen) and alanine aminotransferase levels were obtained for approximately 1.8 million units donated during 1991 and 1992 at five blood centers within the United States. The prevalences of these infectious disease markers in units that the donors confidentially excluded (CUE+) and units that the donors did not exclude (CUE-) were calculated and examined within demographic subgroups. RESULTS: Units that were CUE+ were 8 to 41 times more likely to be seropositive for antibodies to human immunodeficiency virus and hepatitis C virus, hepatitis B surface antigen, and syphilis and three to four times more likely to react for antibody to hepatitis B core (antigen) or to have elevated alanine aminotransferase levels than units that were CUE- (p < 0.001). The positive predictive value of CUE (the percentage of CUE+ units that were confirmed seropositive for any marker) was 3.5 percent, and the sensitivity of CUE (the percentage of confirmed-seropositive units that were CUE+) was 2.3 percent. CONCLUSION: The current CUE process has low sensitivity and apparently low positive predictive value, and in many cases, it appeared that donors misunderstood it. Yet, CUE was not a "random process," as CUE+ units were more likely to be seropositive for any infectious disease marker than CUE- units. This suggests that efforts to improve the CUE system may be warranted. As risk factors for transfusion-transmitted infection become more difficult to identify by history-based screening, however, such efforts may have limited effect.
Adolescent↗
A comparison of immunomagnetic separation and direct culture for the isolation of verocytotoxin-producing Escherichia coli O157 from bovine faeces.
Enrichment culture (EC) in modified buffered peptone water followed by immunomagnetic separation (IMS) with magnetic beads coated with an antibody against Escherichia coli O157 (Dynabeads anti-E. coli O157; Dynal, Oslo) was compared with direct culture on cefixime rhamnose sorbitol MacConkey agar (CR-SMAC) and cefixime tellurite sorbitol MacConkey agar (CT-SMAC) for the isolation of E. coli O157 from bovine faeces. When used to examine bovine faecal suspensions inoculated with 12 different strains of E. coli O157, EC-IMS was c. 100-fold more sensitive for detection of the organism than direct culture on either medium. During monitoring of a dairy herd, E. coli O157 was isolated from 84 (8.2%) of 1024 rectal swabs taken from cattle over a 4-month period; 23 (27.4% of the 84 strains were isolated by both direct culture and IMS (15 of the 23 were isolated on both media, five on CT-SMAC only and three on CR-SMAC only), whereas 61 (72.6%) strains were isolated by IMS only. IMS is a sensitive and simple technique for the isolation of E. coli O157 from bovine faecal samples and should prove useful in elucidating further the epidemiology of this organism.
Animals↗
Acrodermatitis chronica atrophicans: a case report and review of the literature.
We report a 55-year-old woman with acrodermatitis chronica atrophicans (ACA) and a peripheral sensory neuropathy. ACA is an uncommon late cutaneous manifestation of Lyme disease, which follows disseminated Borrelia burgdorferi infection. This is the second published case from the U.K. since serological diagnosis has been available. In this patient the diagnosis was confirmed by serology using a sensitive enzyme-linked immunosorbent assay and immunoblotting techniques. B. burgdorferi DNA was demonstrated in the affected skin using the polymerase chain reaction, although staining and cultures for the organism were negative. Recommended treatment of ACA is with oral doxycycline 100 mg twice daily for 28 days, but our patient did not respond well to this regimen. She was therefore treated with ceftriaxone intravenously for 21 days, which resulted in a rapid symptomatic and clinical response.
Acrodermatitis↗
Predictive value of serology in diagnosing Lyme borreliosis.
AIMS: To compare the predictive value of immunoblotting and enzyme linked immunosorbent assay (ELISA) in diagnosing Lyme borreliosis. METHODS: An ELISA using a whole cell sonicate of the B31 strain of Borrelia burgdorferi was used to screen samples submitted for Lyme borreliosis serology. A total of 1222 serum samples reactive in the ELISA were tested by immunoblotting also using the B31 strain. Patients with other spirochaetal diseases were tested by both methods to assess specificity, while those with erythema migrans were used to evaluate sensitivity. Subjects with different clinical conditions, which may have been associated with Lyme borreliosis, were tested using both techniques. RESULTS: Only 16.3% of serum samples from patients submitted for Lyme borreliosis serology which were reactive by ELISA were confirmed as positive by immunoblotting. This is unlikely to represent a sensitivity problem as 51% of samples from 53 patients with erythema migrans were detected by immunoblotting compared with only 28% by ELISA. Patients whose samples were negative by ELISA were also negative by immunoblotting. Serum samples from patients with relapsing fever were reactive in both ELISA and by immunoblotting, but for other test groups immunoblotting offered increased specificity. CONCLUSIONS: Not all ELISA results could be confirmed by immunoblotting. Yet immunoblotting was both more sensitive and specific than ELISA techniques. As a result of these observations all ELISA results should be serologically confirmed by immunoblotting. Though immunoblotting is not suited to large scale screening of samples, it can be used satisfactorily in conjunction with ELISA methods to improve the predictive value of serological tests for Lyme borreliosis.
Cross Reactions↗
Untreated milk as a source of verotoxigenic E coli O157.
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Animals↗
Purification of glutamine tRNA synthetase from Saccharomyces cerevisiae. A monomeric aminoacyl-tRNA synthetase with a large and dispensable NH2-terminal domain.
Glutamine tRNA synthetase from Saccharomyces cerevisiae has been purified to homogeneity and shown to be a monomer of 91 kDa. The size of the polypeptide agrees with that predicted from the previously reported translated DNA sequence. Mild tryptic digestion removes an amino-terminal domain and releases a fragment of 65 kDa which begins at Ser205. This tryptic fragment is similar in size and sequence to Escherichia coli glutamine tRNA synthetase and shows a modest increase from the full-length yeast enzyme in the Km values for glutamine and ATP and no difference in the kcat for aminoacylation or the Km for tRNA. Thus, the removal of the NH2-terminal domain appears to indirectly affect the ATP- and glutamine-binding sites in the nucleotide-binding fold domain to which the NH2-terminal domain is fused. A monoclonal antibody directed against the NH2-terminal domain of the full-length enzyme has little effect upon the aminoacylation activity. Therefore, over 200 amino acids of the NH2 terminus of the full-length enzyme form a domain that operationally has only a modest influence on the catalytic core of the protein. These studies reinforce the concept that eukaryotic synthetases have quasi-independent domains not found in their prokaryotic counterparts which may confer a function distinct from aminoacylation.
Amino Acid Sequence↗
Acceptor stem and anticodon RNA hairpin helix interactions with glutamine tRNA synthetase.
The class I glutamine (Gln) tRNA synthetase interacts with the anticodon and acceptor stem of glutamine tRNA. RNA hairpin helices were designed to probe acceptor stem and anticodon stem-loop contacts. A seven-base pair RNA microhelix derived from the acceptor stem of tRNA(Gln) was aminoacylated by Gln tRNA synthetase. Variants of the glutamine acceptor stem microhelix implicated the discriminator base as a major identity element for glutaminylation of the RNA helix. A second RNA microhelix representing the anticodon stem-loop competitively inhibited tRNA(Gln) changing. However, the anticodon stem-loop microhelix did not enhance aminoacylation of the acceptor stem microhelix. Thus, transduction of the anticodon identity signal may require covalent continuity of the tRNA chain to trigger efficient aminoacylation.
Acylation↗
Cattle as a possible source of verocytotoxin-producing Escherichia coli O157 infections in man.
In May-June 1992 cases of infection with verocytotoxin-producing (VT+) Escherichia coli O157 in South Yorkshire could have been associated with prior consumption of beef from a local abattoir. During investigation of the abattoir, bovine rectal swabs and samples of meat and surface swabs from beef carcasses were examined for E. coli O157, isolates of which were tested for toxigenicity, plasmid content and phage type. E. coli O157 was isolated from 84 (4%) of 2103 bovine rectal swabs; of these 84, 78 (93%) were VT+, the most common phage types being 2 and 8, the types implicated in the cluster of human cases. Positive cattle were from diverse sources within England. E. coli O157 was isolated from 7 (30%) of 23 carcasses of rectal swab-positive cattle and from 2 (8%) of 25 carcasses of rectal swab-negative cattle. The study has shown that cattle may be a reservoir of VT+ E. coli O157, and that contamination of carcasses during slaughter and processing may be how beef and beef products become contaminated and thereby transmit the organism to man.
Abattoirs↗
Simplified method for the interpretation of immunoblots for Lyme borreliosis.
Interpretation of immunoblot results for Lyme borreliosis remains an area of controversy. This study was undertaken to devise a simple method which incorporated distinctions between specific and non-specific bands. A numerical value was assigned to bands reflecting their relative importance. This scheme was evaluated with sera from 61 forestry workers, which were previously tested by immunoblotting and interpreted subjectively. These results were reported as five separate categories representing levels of reactivity. A total of 72% (44) of sera fell into the same categories as they were originally reported. The method was also assessed with 40 sera routinely submitted for Lyme borreliosis serology. These were interpreted by two members of staff without previous experience of immunoblotting. Their results gave 80% and 72.5% agreement with those of an experienced person used to reading immunoblots for Lyme borreliosis.
Antibodies, Bacterial↗
Early diagnosis of acute myocardial infarction with use of a rapid immunochemical assay of creatine kinase MB isoenzyme.
In 195 patients presenting with chest pain and referred acutely for cardiological assessment, blood was taken immediately for assay of creatine kinase (CK; EC 2.7.3.2) MB isoenzyme by an immunochemical method and results [mass units of enzyme per liter of plasma (microgram/L)] were obtained within 30 min of sampling. Diagnosis of acute myocardial infarction in the patients was made independently, based on electrocardiograms and conventional cardiac enzyme profiles. The administration of any thrombolytic therapy in response to the CK-MB concentration result was also noted, allowing assessment of the assay's potential influence on patient management in addition to the diagnostic efficiency evaluation. The study demonstrated that, when blood samples were collected on admission to hospital and the decision level suggested by the manufacturers was utilized, the assay had an immediate sensitivity of 52% and a specificity of 97%. Of the 81 patients who were shown by conventional means to have had acute myocardial infarction, 8 (10%) had equivocal electrocardiograms but positive CK-MB concentration results. In four of these patients (5%), thrombolytic therapy was given on the basis of the clinical features and a positive CK-MB concentration result alone.
Creatine Kinase↗
Biochemical prediction of changes in spinal bone mass in juvenile chronic (or rheumatoid) arthritis treated with glucocorticoids.
OBJECTIVE: To identify biochemical predictors of spinal bone mineral growth and the development of spinal osteoporosis in children with juvenile chronic arthritis (JCA) treated with glucocorticoids. METHODS: Bone mass measurements were made at 3 monthly intervals for one year in 31 children. At each visit, blood and urine were obtained for assessment of laboratory indices related to the acute phase response and bone remodelling rates. Assessments were also made of joint inflammation (simple joint count). RESULTS: Plasma albumin and C-reactive protein (CRP) concentrations contributed independently of height velocity to the prediction of lumbar spinal bone mineral growth, but only when averaged over the year of observation. The simple joint count did not usefully predict spinal bone mineral changes in the individual patient, nor did any measured index normally related to bone turnover (plasma osteocalcin, 25 (OH) vitamin D, urinary hydroxyproline). Mean values of the simple joint count were predicted by mean CRP and CRP trends. Joint count trends were predicted by hemoglobin trends. None of these relationships, although statistically significant, was strong enough to predict individual outcomes precisely. CONCLUSIONS: Failure of spinal bone mineral growth is related to failure of growth in height and weight but also to biochemical markers for the activation of the acute phase response. Failure of bone growth to correlate with increased hydroxyprolinuria or plasma osteocalcin concentrations may be attributed to the confounding effect of glucocorticoid treatment on plasma osteocalcin levels in children whose bone resorption is little changed from normal levels despite their reduced growth. Biochemical measurements are weak substitutes for bone densitometry in monitoring spinal growth in these children.
Adolescent↗
Small-fiber dysfunction in a Borrelia burgdorferi infection.
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Adult↗
Faculty practice: criterion for academic advancement.
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Career Mobility↗
Cattle as a source of verotoxigenic Escherichia coli O157.
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Animals↗
Staining sections of water-miscible resins. 2. Effects of staining-reagent lipophilicity on the staining of glycol-methacrylate-embedded tissues.
Glycol methacrylate (GMA) sections of animal tissues were stained with a group of twenty-seven reagents of very varied chemical characteristics. The artefactual background staining of the resin was found to be dependent on the hydrophilic/lipophilic character of the staining reagent, as estimated from the logarithm of its octanol-water partition coefficient (log P). Intense background staining occurred with lipophilic stains, whose log P greater than 2. In keeping with this, use of GMA semi-permeable membranes for enzyme histochemistry failed to give staining when using a lipophilic substrate, probably because the substrate was trapped in the membrane. An analysis of other routine histochemical stains--in terms of the probable occurrence of high resin background staining and low tissue sensitivity--is made. A numerical guide is provided to help avoid artefacts resulting from hydrophobic and size effects. Note: small, hydrophilic reagents (log P less than 0; molecular weight less than 550 Da) are least likely to show either type of artefact. Conversely, reagents which are lipophilic, or/and of intermediate size (log P greater than 2; 550 less than ionic weight less than 1000 Da), give strong background staining.
Animals↗
Deficiency of 17 alpha-hydroxylase associated with absent gonads.
A phenotypic female presented initially at the age of 17 years with amenorrhoea and delay of sexual development. Karyotype was male, 46 XY, and as gonads were absent, a diagnosis of congenital anorchia was made. The patient was treated with oestrogen. At the age of 23 years, she re-presented with tall stature and hypertension. She then had normal female habitus but absent pubic and axillary hair. Re-investigation showed that sex steroids and cortisol were absent and established the diagnosis as 17 alpha-hydroxylase deficiency. Treatment with hydrocortisone rapidly corrected the hypertension. Ultrasound examination confirmed the absence of gonads but showed that a small uterus was present. Measurement of serum cortisol is important for recognition of such patients, but further measurements of sex steroids, particularly progesterone, are needed to prove the diagnosis. We have found no previous reports of absent gonads in 17 alpha-hydroxylase deficiency. The association remains unexplained.
Adolescent↗