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Biomedical subjects

W F McNeill

Publications and source records attributed to W F McNeill.

3 recordsLinked to original sources

Cytology of primary versus secondary genital herpesvirus infection.

Certain authors state that primary genital herpes infections mainly produce cells with ground-glass nuclei, whereas secondary infections produce a higher percentage of multinucleated or single cells with prominent intranuclear inclusions. The cervicovaginal smears of 11 patients with primary genital herpes infection and 16 patients with secondary infection were studied to determine the validity of this differentiation. The percentage per patient of virally infected cells containing distinct inclusions ranged from 0% to 35% in the primary herpes group and 0% to 100% in the secondary herpes group. In eight additional patients, the initial herpes simplex virus (HSV)-positive smear was compared with recurrent positive smears taken from 2 to 120 mo later. No statistical difference in the incidence of distinct inclusions in the infected cells was detected. Finally, primary rabbit kidney and the heteroploid A549 cell cultures were inoculated with herpes viruses and followed by fixation with several agents at various time intervals. Alcohol and Bouin's fixative favored the recognition of distinct inclusions, as did the duration of the infection.

Adolescent

Transposable plasmid deoxyribonucleic acid sequence in Pseudomonas aeruginosa which mediates resistance to gentamicin and four other antimicrobial agents.

A 9.1 x 10(6)-dalton transposable deoxyribonucleic acid sequence resides within Pseudomonas aeruginosa plasmid R1033 and mediates resistance to gentamicin, streptomycin, sulfamethoxazole, chloramphenicol, and mercuric chloride. Transposability was demonstrated in Escherichia coli when this sequence, designated Tn1696, excised from R1033 and integrated into plasmid pMB8. Excision and insertion of Tn1696 occurred independently of the host Rec phenotype and may involve the 140-base pair, inverted deoxyribonucleic acid repeated region that flanks this sequence. Occurrence of a multiresistance transposon on a transferrable plasmid that has a broad host range may have serious epidemiological and therapeutic consequences.

Anti-Bacterial Agents

Evolution of multiple-antibiotic-resistance plasmids mediated by transposable plasmid deoxyribonucleic acid sequences.

Two plasmid deoxyribonucleic acid sequences mediating multiple antibiotic resistance transposed in vivo between coexisting plasmids in clinical isolates of Serratia marcescens. This event resulted in the evolution of a transferable multiresistance plasmid. Both sequences, designated in Tn1699 and Tn1700, were flanked by inverted deoxyribonucleic acid repetitions and could transpose between replicons independently of the Excherichia coli recA gene function. Tn1699 and Tn1700 mediated ampicillin, carbenicillin, kanamycin, and gentamicin resistance but differed in the type of gentamicin-acetyltransferase enzymes that they encoded. The structural genes for these enzymes share a great deal of polynucleotide sequence similarity despite their phenotypic differences. The transposition of Tn1699 and Tn1700 to coresident transferable plasmids has contributed to the dissemination of antibiotic resistance among other gram-negative bacteria. These organisms have recently caused nosocomial infections in epidemic proportions.

Anti-Bacterial Agents