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Biomedical subjects

M R Evans

Publications and source records attributed to M R Evans.

At least 91 records · Page 5Linked to original sources
PubMed1990

Biotinyl and phosphotyrosinyl phosphoramidite derivatives useful in the incorporation of multiple reporter groups on synthetic oligonucleotides.

Non-nucleosidic phosphoramidite linker units suitable for use on commercial DNA synthesis machines have been designed for the direct incorporation of biotin and a new reporter group, phosphotyrosine, at multiple sites on synthetic oligonucleotides. The units are based on a 3-carbon glyceryl backbone where the reporter group is attached to the 2-O-position through a 3-aminopropyl spacer. 17-mer oligonucleotides were synthesized carrying at the 5'-end 1, 2, 4 or 8 biotinyl units or 1, 2, 4 or 8 phosphotyrosinyl units respectively and used for the detection of DNA on nitrocellulose filters by hybridization. Subsequent incubation of the filters with a monoclonal antibody to the reporter group followed by secondary detection using enhanced chemiluminescence (ECL) resulted in amplification of signal strengths as the number of reporter groups was increased. The results were quantitated by use of a charge couple device (CCD) camera. Spacing of biotin moieties by thymidyl residues resulted in further improvements in signal strengths, whereas similar spacing of phosphotyrosinyl units did not.

Base Sequence↗
PubMed1990

Potential for laboratory exposures to biohazardous agents found in blood.

The magnitude of risk for occupational exposures to biohazardous agents found in blood was assessed by 800 environmental samples taken from a total of 10 clinical and research laboratories at the National Institutes of Health (NIH). Thirty-one samples from 11 work stations in three laboratories contained hepatitis B virus surface antigen (HBsAg). Observations of workers indicated that environmental contamination arose from several sources. Among the 11 work stations with HBsAg environmental samples, eight had high work loads, seven had inappropriate behaviors, and nine had flawed laboratory techniques. This information suggests that a multifactorial approach is needed to minimize the risk of laboratory-associated infections.

Blood↗
PubMed1980

Isolation and genetic analysis of temperature-sensitive mutants of rhinovirus type 2.

Temperature-sensitive mutants of human rhinovirus type 2 were isolated by random clonings of mutagenized virus. All mutants were stable. Temperature sensitivity was not affected by different host cell systems. Complementation was observed in 3 of 10 dual viral mixtures, with complementation indices being as high as 4.0. Recombination frequencies fluctuated widely between experiments with different mutants, but positive recombination occurred with mean frequencies ranging from 0.03 to 1.25%. The complementation and recombination results obtained are similar to those reported for other picornaviruses.

Genes, Viral↗
PubMedDate not supplied

The detection of positive blood cultures by the BACTEC NR660. The clinical importance of four-day versus seven-day testing.

A total of 471 positive blood cultures obtained over a 3-month period were identified and evaluated for day of positivity by the BACTEC NR660. Of all positive blood cultures, 73% (344) were detected within the first 2 days, and 94% (441) were detected through day 4. The proportion of positive cultures detected at day 5 was significantly lower than that at day 4 (p less than 0.01). Patient chart review revealed that two of 30 isolates (0.4% of all positive isolates) identified on days 5-7 were considered clinically significant and would have been missed if cultures would not have been evaluated for seven days. Therefore, very limited additional patient benefit is derived after greater than 4 days of growth and detection by the BACTEC NR660.

Bacteria↗
PubMedDate not supplied

An outreach education and treatment project in Ghana for the early stage of Mycobacterium ulcerans disease.

Mycobacterium ulcerans disease starts as a painless, subcutaneous nodule, excision of which prevents the development of large Buruli ulcers. An outreach programme was set up in Ghana to promote nodule recognition and excision. The programme was cost-effective and shifted the pattern of disease presentation. This could from a model for other countries.

Cost-Benefit Analysis↗
PubMedDate not supplied

Prevalence and genotype of hepatitis C virus infection in pregnant women and blood donors in Ghana.

The seroprevalence of hepatitis C virus was evaluated in blood donors and antenatal clinic attenders in Kumasi, Ghana and seropositive subjects were tested for hepatitis C virus ribonucleic acid by the polymerase chain reaction (PCR). The overall seroprevalence among Ghanaians was 2.8% but there was a significantly higher prevalence in males (4.6%) than in females (1.0%). No risk factor for infection was identified by a questionnaire. Among those who showed evidence of active infection with a positive PCR, the most common genotype was type 2 but the subtype could not be specifically determined; these type 2 hepatitis C viruses may be indigenous to Africa.

Adolescent↗