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Biomedical subjects

J H Owens

Publications and source records attributed to J H Owens.

10 recordsLinked to original sources
PubMed2000

Characterization of Cryptosporidium parvum by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was used to investigate whole and freeze-thawed Cryptosporidium parvum oocysts. Whole oocysts revealed some mass spectral features. Reproducible patterns of spectral markers and increased sensitivity were obtained after the oocysts were lysed with a freeze-thaw procedure. Spectral-marker patterns for C. parvum were distinguishable from those obtained for Cryptosporidium muris. One spectral marker appears specific for the genus, while others appear specific at the species level. Three different C. parvum lots were investigated, and similar spectral markers were observed in each. Disinfection of the oocysts reduced and/or eliminated the patterns of spectral markers.

Animals↗
PubMed2000

Sequence analysis of the ank gene of granulocytic ehrlichiae.

The ank gene of the agent of human granulocytic ehrlichiosis (HGE) codes for a protein with a predicted molecular size of 131.2 kDa that is recognized by serum from both dogs and humans infected with granulocytic ehrlichiae. As part of an effort to assess the phylogenetic relatedness of granulocytic ehrlichiae from different geographic regions and in different host species, the ank gene was PCR amplified and sequenced from a variety of sources. These included 10 blood specimens from patients with confirmed human granulocytic ehrlichiosis (three from New York, four from Wisconsin, two from Slovenia, and one from Sweden). Also examined was a canine granulocytic ehrlichia sample obtained from Minnesota, Ehrlichia equi from California, Ehrlichia phagocytophila from Sweden, and the granulocytic ehrlichia isolate USG3. The sequences showed a high level of homology (>95.5% identity), with the lowest homology occurring between a New York HGE agent and the Swedish E. phagocytophila. Several 3-bp deletions and a variable number of 51- and 81-bp direct repeats were noted. Although the North American HGE sequences showed the highest conservation (>98.1% identity), phylogenetic analyses indicated that these samples represent two separate clades, one including the three New York HGE samples and the USG3 strain and another with the Wisconsin HGE and Minnesota canine sequences. Two of the New York samples and the USG3 strain showed 100% identity over the entire 3,696-bp product. Likewise, three of the Wisconsin human samples and the Minnesota dog sample were identical (3,693 bp). Whereas phylogenetic analysis showed that the E. equi sequence was most closely related to the Upper Midwest samples, analysis of the repeat structures showed it to be more similar to the European samples. Overall, the genetic analysis based on the ank gene showed that the granulocytic ehrlichiae are closely related, appear to infect multiple species, and can be grouped into at least three different clades, two North American and one European.

Adult↗
PubMed1999

Feline granulocytic ehrlichiosis--a report of a new clinical entity and characterisation of the infectious agent.

A 14-month-old shorthaired cat was presented to the Animal Hospital in Skara, Sweden, with a two-day history of lethargy, anorexia and tachypnoea. Clinical examination and laboratory investigations revealed fever, dehydration, tick infestation, neutrophilia with left shift, lymphopenia, hyperglycaemia and intracytoplasmic neutrophilic Ehrlichia inclusions. After treatment with intravenous doxycycline and lactated Ringer's solution the temperature returned to normal. Oral treatment with doxycycline continued for 20 days. The ehrlichiosis diagnosis was confirmed by serology, polymerase chain reaction and DNA sequencing. No relapse was observed during the eight-month follow-up period. The granulocytotropic Ehrlichia strain found in the cat was later characterised by analysis of the 16S rRNA gene sequence which showed 100 per cent identity to DNA sequences found in Swedish canine and equine granulocytotropic Ehrlichia strains. This is, to the best of the authors' knowledge, the first reported case of granulocytic ehrlichiosis in a cat.

Amino Acid Sequence↗
PubMed1998

Genetic reassortment among viruses causing hantavirus pulmonary syndrome.

In order to determine the frequency and characteristics of reassortment among viruses causing hantavirus pulmonary syndrome (HPS), mixed infections were initiated in tissue culture by using two closely related strains of Sin Nombre virus, CC107 (from eastern California) and NMR11 (from New Mexico), which share the same species of rodent host in nature, the deer mouse (Peromyscus maniculatus). Potential reassortant virus plaques were screened by multiplex RT-PCR, using primers specific for individual genome segments of each strain. Reassortant viruses involving the M and S segments and, to a lesser extent, the L segment were detected in 8.5% of 294 progeny plaques tested. In addition, approximately 30% of the progeny virus plaques appeared to contain S or M segments originating from both parental virus strains, i.e., they were diploid. Most of these diploid virus genotypes were not stable, becoming either reassortant or parental virus strains upon plaque-to-plaque virus passage. In contrast to the results above, only one virus reassortant and four diploids were observed among 163 progeny virus plaques from mixed infections between Sin Nombre virus NMR11 and the genetically more distant Black Creek Canal virus, an HPS-causing virus from Florida, which has the cotton rat (Sigmodon hispidus) as its natural host.

Animals↗
PubMed1998

Nested PCR assay for detection of granulocytic ehrlichiae.

A sensitive and specific nested PCR assay was developed for the detection of granulocytic ehrlichiae. The assay amplifies the 16S rRNA gene and was used to examine acute-phase EDTA-blood and serum samples obtained from seven humans with clinical presentations compatible with human granulocytic ehrlichiosis. Five of the seven suspected cases were positive by the PCR assay using DNA extracted from whole blood as the template, compared with a serologic assay that identified only one positive sample. The PCR assay using DNA extracted from the corresponding serum samples as the template identified three positive samples. The sensitivity of the assay on human samples was examined, and the limit of detection was shown to be fewer than 2 copies of the 16S rRNA gene. The application of the assay to nonhuman samples demonstrated products amplified from template DNA extracted from Ixodes scapularis ticks collected in Rhode Island and from EDTA-blood specimens obtained from white-tailed deer in Maryland. All PCR products were sequenced and identified as specific to granulocytic ehrlichiae. A putative variant granulocytic ehrlichia 16S rRNA gene sequence was detected among products amplified from both the ticks and the deer blood specimens.

Animals↗
PubMedDate not supplied

Extirpation of the fibular sesamoid simplified.

This technique allows the surgeon to maintain a firm grasp on the fibular sesamoid during its dissection, thus minimizing surgical trauma to the surrounding tissue and decreasing the chance of an inadvertent tenotomy of the flexor hallucis longus tendon. The authors have used this technique in 30 sesamoidectomies and found it to lower the frustration level significantly. The only instances in which it does not work as well as expected is with severely osteoporotic sesamoids, and partite sesamoids with fragments too small to pierce with the Kirschner wire. This technique has proved to be relatively simplistic. The small diameter of the Kirschner wire permits both excellent vision of the operative field and easy access to dissection.

Bone Wires↗