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S J O'Brien

Publications and source records attributed to S J O'Brien.

At least 145 records · Page 8Linked to original sources
PubMed1996

Chiari I malformation and spinal cord injury: cause for concern in contact athletes?

We present a case of transient quadriparesis in an 8-yr-old football player with a normal cervical spinal canal but Chiari I malformation of the hindbrain. Chiari I consists of herniation of the cerebellar tonsils through the foramen magnum, which reduces space available for the spinal cord. Magnetic resonance imaging (MRI) of the brain or cervical spine can identify asymptomatic Chiari I, whereas previously myelography was necessary. The incidence and natural history of Chiari I malformation is reviewed, with special reference to the question of return-to-play in young athletes.

Arnold-Chiari Malformation↗
PubMed1996

Prevalence of antibodies to feline parvovirus, calicivirus, herpesvirus, coronavirus, and immunodeficiency virus and of feline leukemia virus antigen and the interrelationship of these viral infections in free-ranging lions in east Africa.

While viral infections and their impact are well studied in domestic cats, only limited information is available on their occurrence in free-ranging lions. The goals of the present study were (i) to investigate the prevalence of antibodies to feline calicivirus (FCV), herpesvirus (FHV), coronavirus (FCoV), parvovirus (FPV), and immunodeficiency virus (FIV) and of feline leukemia virus (FeLV) antigen in 311 serum samples collected between 1984 and 1991 from lions inhabiting Tanzania's national parks and (ii) to evaluate the possible biological importance and the interrelationship of these viral infections. Antibodies to FCV, never reported previously in free-ranging lions, were detected in 70% of the sera. In addition, a much higher prevalence of antibodies to FCoV (57%) was found than was previously reported in Etosha National Park and Kruger National Park. Titers ranged from 25 to 400. FeLV antigen was not detectable in any of the serum samples. FCoV, FCV, FHV, and FIV were endemic in the Serengeti, while a transient elevation of FPV titers pointed to an outbreak of FPV infection between 1985 and 1987. Antibody titers to FPV and FCV were highly prevalent in the Serengeti (FPV, 75%; FCV, 67%) but not in Ngorongoro Crater (FPV, 27%; FCV, 2%). These differences could be explained by the different habitats and biological histories of the two populations and by the well-documented absence of immigration of lions from the Serengeti plains into Ngorongoro Crater after 1965. These observations indicate that, although the pathological potential of these viral infections seemed not to be very high in free-ranging lions, relocation of seropositive animals by humans to seronegative lion populations must be considered very carefully.

Africa, Eastern↗
PubMed1996

Genetic and phylogenetic divergence of feline immunodeficiency virus in the puma (Puma concolor).

Feline immunodeficiency virus (FIV) is a lentivirus which causes an AIDS-like disease in domestic cats (Felis catus). A number of other felid species, including the puma (Puma concolor), carry a virus closely related to domestic cat FIV. Serological testing revealed the presence of antibodies to FIV in 22% of 434 samples from throughout the geographic range of the puma. FIV-Pco pol gene sequences isolated from pumas revealed extensive sequence diversity, greater than has been documented in the domestic cat. The puma sequences formed two highly divergent groups, analogous to the clades which have been defined for domestic cat and lion (Panthera leo) FIV. The puma clade A was made up of samples from Florida and California, whereas clade B consisted of samples from other parts of North America, Central America, and Brazil. The difference between these two groups was as great as that reported among three lion FIV clades. Within puma clades, sequence variation is large, comparable to between-clade differences seen for domestic cat clades, allowing recognition of 15 phylogenetic lineages (subclades) among puma FIV-Pco. Large sequence divergence among isolates, nearly complete species monophyly, and widespread geographic distribution suggest that FIV-Pco has evolved within the puma species for a long period. The sequence data provided evidence for vertical transmission of FIV-Pco from mothers to their kittens, for coinfection of individuals by two different viral strains, and for cross-species transmission of FIV from a domestic cat to a puma. These factors may all be important for understanding the epidemiology and natural history of FIV in the puma.

Amino Acid Sequence↗
PubMed1996

Labral injuries: accuracy of detection with unenhanced MR imaging of the shoulder.

PURPOSE: To prospectively assess the accuracy of unenhanced magnetic resonance (MR) imaging in the detection and localization of labral injuries. MATERIALS AND METHODS: One hundred three patients with clinically suspected shoulder injuries were prospectively examined with unenhanced MR imaging. A combination of gradient-echo and high-resolution fast-spin-echo axial pulse sequences were used. Surgical correlation was obtained in all patients. RESULTS: At surgery, 37 torn anterior, 36 torn superior, and 19 torn posterior labral were identified. The sensitivity for detection of these tears with MR imaging was 100%, 86%, and 74%, respectively; the specificity was 95%, 100%, and 95%, respectively. Overall, unenhanced MR imaging was 95% accurate in the detection of labral injuries. CONCLUSION: With appropriate pulse sequences, unenhanced MR imaging of the shoulder is an accurate technique for the detection and localization of labral injuries.

Adult↗
PubMed1995

Hypervariable genomic variation to reconstruct the natural history of populations: lessons from the big cats.

The extent and nature of variation in hypervariable regions DNA have been used in the past as a means to infer the natural histories of populations. We review the interpretation of the extent of genetic diversity for minisatellite DNA in the cheetah to estimate the timing of a population bottleneck in the species and the potential application of a second class of hypervariable DNA, microsatellite DNA, as a molecular tool to examine the natural histories of felid populations. A calibration curve relating the degree of allele fragment sharing in individuals to relatedness in a captive pedigree of cheetahs is presented. This measurement has important applications for management of potential matings in captive management situations.

Acinonyx↗
PubMed1995

African horse sickness and African carnivores.

African horse sickness (AHS) is a disease that affects equids, and is principally transmitted by Culicoides spp. that are biological vectors of AHS viruses (AHSV). The repeated spread of AHSV from sub-Saharan Africa to the Middle East, northern Africa and the Iberian peninsula indicate that a better understanding of AHS epizootiology is needed. African horse sickness has long been known to infect and cause mortality among domestic dogs that ingest virus contaminated meat, but it is uncertain what role carnivores play in transmission of the virus. We present evidence of widespread natural AHS infection among a diversity of African carnivore species. We hypothesize that such infection resulted from ingestion of meat and organs from AHS-infected prey species. The effect of AHS on the carnivores is unknown, as is their role in the maintenance cycle of the disease.

Africa↗
PubMed1995

Coadaptation and immunodeficiency virus: lessons from the Felidae.

The emergence of pathogenic viruses in new species offers an unusual opportunity to monitor the coadaptation of viruses and their hosts in a dynamic ongoing process of intense biological selection. Tracking lentivirus epidemics in man, monkeys and cats reveals genomic struggles at three levels: quasispecies divergence within an individual; coadaptation of virus and host genomes subsequent to disease outbreaks; and transmission, spread and pathogenesis in related host species. Aspects of each level are revealed by examining the genetic diversity of feline immunodeficiency virus in domestic and wild cat species. This approach has been facilitated by the recent genetic characterization of a novel lentivirus in lions.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Sporadic isolates of Escherichia coli O157.H7 investigated by pyrolysis mass spectrometry.

Thirty-six encoded isolates of Escherichia coli. 32 of which were of serotype O157, were examined by pyrolysis mass spectrometry (PyMS). Thirty-one of the serotype O157 isolates possessed the flagellar antigen H7 and produced Verocytotoxin (VT), the other isolate serotyped as H45 and was non-toxigenic. Eighteen of the VT-producing E. coli (VTEC) isolates were from sporadic disease in residents of the Northern Region. Standard principal component (PC) and canonical variate (CV) analysis of the data distinguished only the four non-O157 isolates from the remainder which were indistinguishable by this approach. A similarity matrix based on differences between individual CV means distinguished a further ten isolates. The matrix correctly clustered 2 pairs of isolates from siblings and 4 isolates from an affected family. A further 5 clusters of 3 or more isolates and 6 pairs of isolates were defined. These groupings proved to be homogenous for toxin phenotype but occasionally entrained isolates of dissimilar phage type. However, in general, PyMS-derived clustering of apparently sporadic isolates accorded with geographical locations as determined by postcode. PyMS, which is a quick and high volume capacity phenotypic technique, may be a useful addition to existing methods in the investigation of the epidemiology of sporadic VTEC disease.

Escherichia coli↗
PubMed1995

Molecular evolution of mitochondrial 12S RNA and cytochrome b sequences in the pantherine lineage of Felidae.

DNA sequence comparisons of two mitochondrial DNA genes were used to infer phylogenetic relationships among 17 Felidae species, notably 15 in the previously described pantherine lineage. The polymerase chain reaction (PCR) was used to generate sequences of 358 base pairs of the mitochondrial 12S RNA gene and 289 base pairs of the cytochrome b protein coding gene. DNA sequences were compared within and between 17 felid and five nonfelid carnivore species. Evolutionary trees were constructed using phenetic, cladistic, and maximum likelihood algorithms. The combined results suggested several phylogenetic relationships including (1) the recognition of a recently evolved monophyletic genus Panthera consisting of Panthera leo, P. pardus, P. onca, P. uncia, P. tigris, and Neofelis nebulosa; (2) the recent common ancestry of Acinonyx jubatus, the African cheetah, and Puma concolor, the American puma; and (3) two golden cat species, Profelis temmincki and Profelis aurata, are not sister species, and the latter is strongly associated with Caracal caracal. These data add to the growing database of vertebrate mtDNA sequences and, given the relatively recent divergence among the felids represented here (1-10 Myr), allow 12S and cytochrome b sequence evolution to be addressed over a time scale different from those addressed in most work on vertebrate mtDNA.

Acinonyx↗
PubMed1995

Lateral epicondylitis: correlation of MR imaging, surgical, and histopathologic findings.

PURPOSE: To determine the value of magnetic resonance (MR) imaging in the clinical management of chronic refractory lateral epicondylitis. MATERIALS AND METHODS: Coronal three-dimensional Fourier transform, multiplanar gradient-recalled-echo, and fat-suppressed sagittal images were obtained in 33 patients. Twenty of these patients underwent surgical débridement and/or primary tendon repair and were included in the correlative study. Surgical and pathologic reports were reviewed to determine the location and gross characteristics of the tissue. RESULTS: Findings at MR imaging correlated with the surgical findings of primary degeneration of the extensor carpi radialis brevis (n = 20). Histopathologic examination demonstrated neovascularization, disruption of collagen, and mucoid degeneration without inflammation. CONCLUSION: The use of MR imaging in patients with recalcitrant lateral epicondylitis assists in surgical planning. The definition of tendon degeneration and degree of tear, as depicted on MR images, correlate well with surgical and histologic findings.

Adult↗
PubMed1995

Assignment of islet amyloid polypeptide (IAPP) gene to feline chromosome B4 using the polymerase chain reaction technique on feline-rodent hybrid cell lines.

The most characteristic morphologic features of the pancreatic islets of human non-insulin-dependent diabetes mellitus (NIDDM, or type 2 diabetes mellitus) and of similar forms of diabetes in cats and macaques are the deposition of amyloid (islet amyloid) and the loss of beta cells. Islet amyloid is derived from islet amyloid polypeptide (IAPP), which is a normal secretory product of the beta cells. Therefore, knowledge of the IAPP gene is of potential importance in defining the pathogenesis of NIDDM. To identify the feline chromosome(s) on which the IAPP gene is located, we screened genomic DNA obtained from 38 feline-rodent hybrid cell lines that have a known feline chromosome content. Feline IAPP DNA was amplified and detected using the polymerase chain reaction technique. Discordancy analysis for each feline chromosome showed that chromosome B4 had the lowest discordancy (P < 0.0001). Feline chromosome B4 shows an extensive conserved syntenic relationship with human chromosome 12, on which the human IAPP gene is located. This study therefore extends and confirms the homology between human chromosome 12 and feline chromosome B4 and provides an additional genetic marker for feline chromosome B4.

Amyloid↗
PubMed1995

Symptomatic ossification of the tibiofibular syndesmosis in professional football players: a sequela of the syndesmotic ankle sprain.

Ankle syndesmosis sprains are common injuries in collegiate and professional football. Several reports have documented that patients with syndesmosis injuries require a longer time to return to full athletic participation than patients with lateral ankle sprains. Here we present the cases of two professional football players with ankle pain secondary to syndesmosis ossification following documented syndesmosis ankle sprains. Both patients eventually required resection of the heterotopic ossification to allow a pain-free return to football. We conclude that syndesmosis ossification may be symptomatic in some patients, and surgical excision of the ossification may be required to allow an asymptomatic return to sports.

Ankle↗
PubMed1995

Arthroscopic evaluation of the unstable shoulder.

The arthroscopic evaluation of glenohumeral instability is based upon having a firm understanding of normal arthroscopic anatomy and knowledge of the structures responsible for the static and dynamic control of glenohumeral translation. Once this has been mastered, shoulder arthroscopy in combination with EUA can play an integral role in the management of shoulder instability. EUA's use in the dislocator is established in the decision of when to proceed with open or arthroscopic stabilization, and its role for prognostic purposes in this situation is less well-defined. For occult instability, shoulder arthroscopy can be diagnostic and be an aid to deciding whether open or arthroscopic stabilization is appropriate.

Arm Injuries↗
PubMed1994

Nucleotide sequence analysis of puma lentivirus (PLV-14): genomic organization and relationship to other lentiviruses.

The complete nucleotide sequence of an isolate of puma lentivirus (PLV-14) was obtained by an inverse polymerase chain reaction (I-PCR) technique and confirmed by conventional PCR. Both methods were used to amplify overlapping regions of proviral DNA, for cloning and sequencing, from genomic DNA isolated from PLV-14 infected Florida puma (Felis concolor coryi) peripheral blood mononuclear cells (PBMC). The provirus has a total length of 9100 nucleotides and the genomic organization of presumed protein coding regions are similar to those seen in other members of the lentivirus family, i.e., three large open reading frames gag, pol, and env as well as smaller intergenic regions that apparently encode regulatory proteins vif and 3' rev by positional and sequence similarity to those seen in other lentiviruses. Two additional open reading frames were identified in the env region and their function (if any) is unknown. The length of the PLV-14 long terminal repeat (LTR) was found to be shorter than the LTRs of feline immunodeficiency virus (FIV). The sequence homology between PLV-14 and other lentiviruses demonstrates that PLV-14 is most closely related to FIV from domestic cats. However, the extent of sequence divergence of each retroviral gene segment is large (e.g., percentage sequence similarity between FIV and PLV-14 env is 8% amino acid and 37% nucleotide similarity), indicating relatively ancient divergence of these feline lentiviral genomes.

Amino Acid Sequence↗