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Biomedical subjects

Robert J Moore

Publications and source records attributed to Robert J Moore.

At least 19 recordsLinked to original sources
PubMed2006

Suppression of bovine viral diarrhea virus replication by small interfering RNA and short hairpin RNA-mediated RNA interference.

Bovine viral diarrhea virus (BVDV) is a ubiquitous viral pathogen that affects cattle herds' worldwide causing significant economic loss. The current strategies to control BVDV infection include vaccination (modified-live or killed) and control of virus spread by enhanced biosecurity management, however, the disease remains prevalent. With the discovery of the sequence-specific method of gene silencing known as RNA interference (RNAi), a new era in antiviral therapies has begun. Here we report the efficient inhibition of BVDV replication by small interfering (siRNA) and short hairpin RNA (shRNA)-mediated gene silencing. siRNAs were generated to target the 5' non-translated (NTR) region and the regions encoding the C, NS4B and NS5A proteins of the BVDV genome. The siRNAs were first validated using an EGFP/BVDV reporter system and were then shown to suppress BVDV-induced cytopathic effects and viral titers in cell culture with surprisingly different activities compared to the reporter system. Efficient viral suppression was then achieved by bovine 7SK-expressed BVDV-specific shRNAs. Overall, our results demonstrated the use of siRNA and shRNA-mediated gene silencing to achieve efficient inhibition of the replication of this virus in cell culture.

Animals↗
PubMed2006

Alpha-toxin of Clostridium perfringens is not an essential virulence factor in necrotic enteritis in chickens.

The Clostridium perfringens alpha-toxin has previously been implicated as the major virulence factor in necrotic enteritis in chickens, although definitive proof has not been reported. In this study an alpha-toxin mutant was constructed in a virulent chicken isolate and shown to retain full virulence in a chicken disease model. These results demonstrated that alpha-toxin is not an essential virulence factor in the pathogenesis of necrotic enteritis in chickens.

Animals↗
PubMed2006

The vertebral endplate: disc degeneration, disc regeneration.

The vertebral endplates are critical for maintaining disc function yet like other components of the disc are vulnerable to degeneration. This paper provides an overview of the development and normal function of the endplates as well as an impression of what happens when they undergo progressive degeneration. Recent research suggests that the degenerative process can be retarded or reversed.

Back Pain↗
PubMed2006

Muscular contributions to dynamic dorsoventral lumbar spine stiffness.

Spinal musculature plays a major role in spine stability, but its importance to spinal stiffness is poorly understood. We studied the effects of graded trunk muscle stimulation on the in vivo dynamic dorsoventral (DV) lumbar spine stiffness of 15 adolescent Merino sheep. Constant voltage supramaximal electrical stimulation was administered to the L3-L4 interspinous space of the multifidus muscles using four stimulation frequencies (2.5, 5, 10, and 20 Hz). Dynamic stiffness was quantified at rest and during muscle stimulation using a computer-controlled testing apparatus that applied variable frequency (0.46-19.7 Hz) oscillatory DV forces (13-N preload to 48-N peak) to the L3 spinous process of the prone-lying sheep. Five mechanical excitation trials were randomly performed, including four muscle stimulation trials and an unstimulated or resting trial. The secant stiffness (k (y) = DV force/L3 displacement, kN/m) and loss angle (phase angle, deg) were determined at 44 discrete mechanical excitation frequencies. Results indicated that the dynamic stiffness varied 3.7-fold over the range of mechanical excitation frequencies examined (minimum resting k (y) = 3.86 +/- 0.38 N/mm at 4.0 Hz; maximum k (y) = 14.1 +/- 9.95 N/mm at 19.7 Hz). Twenty hertz muscle stimulation resulted in a sustained supramaximal contraction that significantly (P < 0.05) increased k (y) up to twofold compared to rest (mechanical excitation at 3.6 Hz). Compared to rest, k (y) during the 20 Hz muscle stimulation was significantly increased for 34 of 44 mechanical excitation frequencies (mean increase = 55.1%, P < 0.05), but was most marked between 2.55 and 4.91 Hz (mean increase = 87.5%, P < 0.05). For lower frequency, sub-maximal muscle stimulation, there was a graded change in k (y), which was significantly increased for 32/44 mechanical excitation frequencies (mean increase = 40.4%, 10 Hz stimulus), 23/44 mechanical excitation frequencies (mean increase = 10.5%, 5 Hz stimulus), and 11/44 mechanical excitation frequencies (mean increase = 4.16%, 2.5 Hz stimulus) when compared to rest. These results indicate that the dynamic mechanical behavior of the ovine spine is modulated by muscle stimulation, and suggests that muscle contraction plays an important role in stabilizing the lumbar spine.

Animals↗
PubMed2006

Increased multiaxial lumbar motion responses during multiple-impulse mechanical force manually assisted spinal manipulation.

BACKGROUND: Spinal manipulation has been found to create demonstrable segmental and intersegmental spinal motions thought to be biomechanically related to its mechanisms. In the case of impulsive-type instrument device comparisons, significant differences in the force-time characteristics and concomitant motion responses of spinal manipulative instruments have been reported, but studies investigating the response to multiple thrusts (multiple impulse trains) have not been conducted. The purpose of this study was to determine multi-axial segmental and intersegmental motion responses of ovine lumbar vertebrae to single impulse and multiple impulse spinal manipulative thrusts (SMTs). METHODS: Fifteen adolescent Merino sheep were examined. Tri-axial accelerometers were attached to intraosseous pins rigidly fixed to the L1 and L2 lumbar spinous processes under fluoroscopic guidance while the animals were anesthetized. A hand-held electromechanical chiropractic adjusting instrument (Impulse) was used to apply single and repeated force impulses (13 total over a 2.5 second time interval) at three different force settings (low, medium, and high) along the posteroanterior axis of the T12 spinous process. Axial (AX), posteroanterior (PA), and medial-lateral (ML) acceleration responses in adjacent segments (L1, L2) were recorded at a rate of 5000 samples per second. Peak-peak segmental accelerations (L1, L2) and intersegmental acceleration transfer (L1-L2) for each axis and each force setting were computed from the acceleration-time recordings. The initial acceleration response for a single thrust and the maximum acceleration response observed during the 12 multiple impulse trains were compared using a paired observations t-test (POTT, alpha = .05). RESULTS: Segmental and intersegmental acceleration responses mirrored the peak force magnitude produced by the Impulse Adjusting Instrument. Accelerations were greatest for AX and PA measurement axes. Compared to the initial impulse acceleration response, subsequent multiple SMT impulses were found to produce significantly greater (3% to 25%, P < 0.005) AX, PA and ML segmental and intersegmental acceleration responses. Increases in segmental motion responses were greatest for the low force setting (18%-26%), followed by the medium (5%-26%) and high (3%-26%) settings. Adjacent segment (L1) motion responses were maximized following the application of several multiple SMT impulses. CONCLUSION: Knowledge of the vertebral motion responses produced by impulse-type, instrument-based adjusting instruments provide biomechanical benchmarks that support the clinical rationale for patient treatment. Our results indicate that impulse-type adjusting instruments that deliver multiple impulse SMTs significantly increase multi-axial spinal motion.

Journal Article↗
PubMed2006

Active head movements facilitate compensation for effects of prism displacement on dynamic gait.

STUDY DESIGN: Four groups, between-subjects study. OBJECTIVES: To investigate the effects of exercise on adaptation of normal subjects who had been artificially spatially disoriented. BACKGROUND: Many patients referred for rehabilitation experience sensory changes, due to age or disease processes, and these changes affect motor skill. The best way to train patients to adapt to these changes and to improve their sensorimotor skills is unclear. Using normal subjects, we tested the hypothesis that active, planned head movement is needed to adapt to modified visual input. METHODS AND MEASURES: Eighty male and female subjects who had normal balance on computerized dynamic posturography (CDP) and the dynamic gait index (DGI), were randomly assigned to four groups. All groups donned diagonally shift lenses and were again assessed with CDP and DGI. The four groups were then treated for 20 min. Group 1 (control group) viewed a video, Group 2 performed exercise that involved translating the entire body through space, but without separate, volitional head movement, Group 3 performed exercises which all incorporated volitional, planned head rotations, and Group 4 performed exercises that involved translating the body (as in Group 2) and incorporated volitional, planned head motion (as in Group 3). All subjects were post-tested with CDP and DGI, lenses were removed, and subjects were retested again with CDP and DGI. RESULTS: The groups did not differ significantly on CDP scores but Groups 3 and 4 had significantly better DGI scores than Groups 1 and 2. CONCLUSIONS: Active head movement that is specifically planned as part of the exercise is more effective than passive attention or head movements that are not consciously planned, for adapting to sensorimotor change when it incorporates active use of the changed sensory modality, in this case head motion.

Adaptation, Physiological↗
PubMed2005

Spinal manipulation force and duration affect vertebral movement and neuromuscular responses.

BACKGROUND: Previous study in human subjects has documented biomechanical and neurophysiological responses to impulsive spinal manipulative thrusts, but very little is known about the neuromechanical effects of varying thrust force-time profiles. METHODS: Ten adolescent Merino sheep were anesthetized and posteroanterior mechanical thrusts were applied to the L3 spinous process using a computer-controlled, mechanical testing apparatus. Three variable pulse durations (10, 100, 200 ms, force = 80 N) and three variable force amplitudes (20, 40, 60 N, pulse duration = 100 ms) were examined for their effect on lumbar motion response (L3 displacement, L1, L2 acceleration) and normalized multifidus electromyographic response (L3, L4) using a repeated measures analysis of variance. FINDINGS: Increasing L3 posteroanterior force amplitude resulted in a fourfold linear increase in L3 posteroanterior vertebral displacement (p < 0.001) and adjacent segment (L1, L2) posteroanterior acceleration response (p < 0.001). L3 displacement was linearly correlated (p < 0.001) to the acceleration response over the 20-80 N force range (100 ms). At constant force, 10 ms thrusts resulted in nearly fivefold lower L3 displacements and significantly increased segmental (L2) acceleration responses compared to the 100 ms (19%, p = 0.005) and 200 ms (16%, p = 0.023) thrusts. Normalized electromyographic responses increased linearly with increasing force amplitude at higher amplitudes and were appreciably affected by mechanical excitation pulse duration. INTERPRETATION: Changes in the biomechanical and neuromuscular response of the ovine lumbar spine were observed in response to changes in the force-time characteristics of the spinal manipulative thrusts and may be an underlying mechanism in related clinical outcomes.

Animals↗
PubMed2005

The Brachyspira hyodysenteriae ftnA gene: DNA vaccination and real-time PCR quantification of bacteria in a mouse model of disease.

The nucleotide sequence of the Brachyspira hyodysenteriae ftnA gene, encoding a putative ferritin protein (FtnA), was determined. Analysis of the sequence predicted that this gene encoded a protein of 180 amino acids. RT-PCR and Western blot showed that the ftnA gene was expressed in B. hyodysenteriae, and evidence suggests that FtnA stores iron rather than haem. ftnA was delivered as DNA and recombinant protein vaccines in a mouse model of B. hyodysenteriae infection. Vaccine efficacy was monitored by caecal pathology and quantification of B. hyodysenteriae numbers in the caeca of infected mice by real-time PCR.

Amino Acid Sequence↗
PubMed2005

Effects of intervertebral disc infection on the developing ovine spine.

STUDY DESIGN: A prospective in vivo animal study. OBJECTIVES: To determine whether infection in the juvenile spine influences spinal development. SUMMARY OF BACKGROUND DATA: Discitis is thought to occur in children when blood-borne infection penetrates the highly vascular immature disc. The condition generally resolves without apparent complication, but little is known about the long-term effects on the growing spine. METHODS: Twenty-nine 6-week-old lambs underwent discography at multiple lumbar levels using radiographic contrast deliberately inoculated with Staphylococcus epidermidis. No antibiotics were given. Plain radiographs were taken at intervals up to 52 weeks after inoculation for morphometric analysis of the vertebral bodies and discs, and the lumbar spines were prepared for histology. RESULTS: Sixteen of 44 inoculated discs showed radiological evidence of discitis between 2 and 6 weeks after inoculation. Disc height and disc area were significantly reduced from 2 weeks, and did not recover during the study period. Vertebral body dimensions and overall lumbar spine length were not significantly affected. CONCLUSION: Infection of juvenile ovine discs impedes disc development but has no significant effect on vertebral body growth.

Animals↗
PubMed2005

Characterisation and application of a bovine U6 promoter for expression of short hairpin RNAs.

BACKGROUND: The use of small interfering RNA (siRNA) molecules in animals to achieve double-stranded RNA-mediated interference (RNAi) has recently emerged as a powerful method of sequence-specific gene knockdown. As DNA-based expression of short hairpin RNA (shRNA) for RNAi may offer some advantages over chemical and in vitro synthesised siRNA, a number of vectors for expression of shRNA have been developed. These often feature polymerase III (pol. III) promoters of either mouse or human origin. RESULTS: To develop a shRNA expression vector specifically for bovine RNAi applications, we identified and characterised a novel bovine U6 small nuclear RNA (snRNA) promoter from bovine sequence data. This promoter is the putative bovine homologue of the human U6-8 snRNA promoter, and features a number of functional sequence elements that are characteristic of these types of pol. III promoters. A PCR based cloning strategy was used to incorporate this promoter sequence into plasmid vectors along with shRNA sequences for RNAi. The promoter was then used to express shRNAs, which resulted in the efficient knockdown of an exogenous reporter gene and an endogenous bovine gene. CONCLUSION: We have mined data from the bovine genome sequencing project to identify a functional bovine U6 promoter and used the promoter sequence to construct a shRNA expression vector. The use of this native bovine promoter in shRNA expression is an important component of our future development of RNAi therapeutic and transgenic applications in bovine species.

Animals↗
PubMed2005

The role of vestibular rehabilitation in the treatment of Meniere's disease.

OBJECTIVE: To study the role of vestibular rehabilitation is treating patients with Meniere's disease. METHODS: We examined all Meniere's patients presenting to our tertiary care specialized vestibular clinic during a 1-year period. All patients underwent a standardized history and physical examination, a complete auditory-vestibular test battery, and a set of physical therapy tools to measure balance function. RESULTS: A subset of patients suffered from disequilibrium or unsteadiness between attacks. Once the acute fluctuating symptoms of Meniere's were controlled in this group of individuals, all of them underwent vestibular physical therapy and demonstrated significant improvement in balance function on both objective and self-report tests. CONCLUSIONS: Due to the fluctuating nature of the disorder, vestibular physical therapy has had a limited role in the treatment of Meniere's disease. In general, rehabilitation has been used only as a postoperative treatment for the acute vertigo seen after vestibular neurectomy or labyrinthectomy. This is the first report advocating the role of vestibular physical therapy in a group of patients receiving medical therapy of intraear medicines (other that gentamicin).

Adult↗
PubMed2005

Vestibular rehabilitation for migraine-associated dizziness.

The purpose of this study was to investigate the effects of a vestibular rehabilitation program on patients with the diagnosis of migraine-associated dizziness. Subjects were placed in four groups as follows: idiopathic migraine-associated dizziness; idiopathic migraine-associated dizziness and associated benign positional vertigo; posttraumatic migraine-associated dizziness; and posttraumatic migraine-associated dizziness and benign positional vertigo. Vestibular rehabilitation therapy was administered to all patients. Criterion measurements included the dizziness handicap inventory, activities-specific balance confidence scale, computerized dynamic posturography performance, and dynamic gait index. After vestibular physical therapy, all subjects showed significant improvement in the dizziness handicap, activities-specific balance confidence, dynamic gait, and computerized dynamic posturography measures. Patients with migraine-associated dizziness can benefit from physical therapy intervention. The results of this study are important in considering the approach to vertiginous migraine patients with and without head injury.

Adolescent↗
PubMed2004

TNF-alpha regulates epithelial expression of MMP-9 and integrin alphavbeta6 during tumour promotion. A role for TNF-alpha in keratinocyte migration?

Mice deficient in TNF-alpha (TNF-alpha(-/-) mice) are resistant to skin carcinogenesis and expression of MMP-9 is inhibited in TNF-alpha(-/-) mice during skin tumour development. In the early stages of tumour promotion, MMP-9 protein initially localized to the follicular epidermis but subsequently began to accumulate in the interfollicular epidermis of wild-type but not TNF-alpha(-/-) mice. Inhibition of TNF-alpha or MMP-9 function reduced keratinocyte migration in vitro. In addition, a deficiency of TNF-alpha delayed re-epithelialization in vivo and this correlated with reduced MMP-9 expression. Collectively, these data suggest that MMP-9 regulates keratinocyte migration in a TNF-alpha-dependent manner. Expression profiling of genes that control cell adhesion and migration revealed markedly lower levels of the integrin subunits alphav and beta6 in TNF-alpha(-/-) compared with wild-type keratinocytes in vitro. alphavbeta6 expression was upregulated by keratinocytes in vitro and during tumour promotion in vivo in a TNF-alpha-dependent manner. Furthermore, alphavbeta6 blockade significantly inhibited keratinocyte migration and TNF-alpha-stimulated MMP-9 expression in vitro. These data illustrate a novel TNF-alpha-dependent mechanism for the control of alphavbeta6 expression and suggest one pathway for TNF-alpha regulation of MMP-9. Increased MMP-9 and alphavbeta6 expression may stimulate epithelial cell migration during tumour formation and may be one mechanism whereby TNF-alpha acts as an endogenous tumour promoter.

Animals↗
PubMed2004

Expression of both TNF-alpha receptor subtypes is essential for optimal skin tumour development.

Keratinocyte-derived TNF-alpha acts as an endogenous tumour promoter and can also regulate AP-1 activity in mouse epidermis. To gain further insight into TNF-alpha signalling during skin tumour formation, mice deficient in TNFR1 (TNFR1-/- mice) or TNFR2 (TNFR2-/- mice) were subjected to chemical carcinogenesis. Tumour multiplicity was significantly reduced in TNFR1-/- and TNFR2-/- mice compared to wild-type (wt) mice, suggesting that both receptors have protumour activity. However, TNFR1-/- mice were markedly more resistant to tumour development than TNFR2-/- mice indicating that TNFR1 is the major mediator of TNF-alpha-induced tumour formation. TNFR1 and TNFR2 were both expressed in wt epidermis during tumour promotion and by primary keratinocytes in vitro. TPA-induced c-Jun expression was transient in TNFR1-/- and TNFR2-/- compared to wt epidermis and this was reflected by reduced induction of the AP-1-responsive genes granulocyte/macrophage-colony stimulating factor, matrix metalloproteinase-9 and matrix metalloproteinase-3. These genes were differentially regulated in TNFR1-/- compared to TNFR2-/- epidermis, suggesting that the TNF-alpha receptors act independently via different AP-1 complexes to transduce TNF-alpha signals during tumour promotion. In addition, TNFR2 cooperated with TNFR1 to optimise TNFR1-mediated TNF-alpha bioactivity on keratinocytes in vitro. Our data provide further insight into TNF-alpha signalling in malignancy and provide some rationale for the use of TNF-alpha antagonists in the treatment of cancer.

Animals↗
PubMed2004

Recovery of Mycobacterium avium subspecies paratuberculosis from the natural host for the extraction and analysis in vivo-derived RNA.

RNA has been extracted and analysed from in vivo-derived Mycobacterium avium subspecies paratuberculosis recovered from the natural host. The bacteria were selectively extracted from the intestinal tissue of two goats exhibiting clinical signs of Johne's disease. Small intestine was rapidly removed, luminal contents washed away and the mucosa and submucosa harvested. Mycobacteria in this material were released from the macrophages by isotonic lysis and differential centrifugation. RNA was extracted and compared with RNA extracted from bacteria grown in vitro. Real-time polymerase chain reaction was used to analyse the katG gene from the bacterial messenger RNA. The katG mRNA encoding the putative catalase/peroxidase showed differential expression in the in vivo and in vitro-derived samples. We hypothesize that the increase in katG expression for in vivo-derived M. paratuberculosis may represent a response to the oxidative stress encountered within the intra-macrophage environment.

Adaptation, Physiological↗
PubMed2004

Highly conserved alpha-toxin sequences of avian isolates of Clostridium perfringens.

Clostridium perfringens causes necrotic enteritis in chickens, and alpha-toxin has been suggested to be a key virulence determinant. Analysis of the alpha-toxin of 25 chicken-derived C. perfringens strains demonstrated high homology to mammal-derived strains rather than to the only avian-derived C. perfringens alpha-toxin sequence reported previously.

Amino Acid Sequence↗
PubMed2003

Does intradiscal electrothermal therapy denervate and repair experimentally induced posterolateral annular tears in an animal model?

STUDY DESIGN: The effects of intradiscal electrothermal therapy (IDET) on intervertebral discs in sheep were studied experimentally. OBJECTIVES: Posterolateral annular lesions were experimentally induced and allowed to mature for 12 weeks in the intervertebral discs of sheep. IDET was performed in an attempt to denervate and repair the annular lesion. The histologic and immunohistochemical effects of IDET were studied. SUMMARY OF BACKGROUND DATA: IDET continues to be used as a minimally invasive treatment for chronic discogenic low back pain, with success rates reported in up to 70% of cases. The mechanism of action by which IDET exerts its effect is poorly understood. Proposed mechanisms include the contraction of collagen and the coagulation of annular nociceptors. An ovine model was used firstly to induce a posterolateral annular lesion, secondly to assess the innervation of such a lesion, and thirdly to assess the effect of IDET on this innervation. MATERIALS AND METHODS: Posterolateral annular incisions were made in 40 lumbar discs of 20 sheep. Twelve weeks were allowed for each annular lesion to mature. IDET was then performed in the disc with the posterolateral annular tear and in another control level. IDET was performed using a modified intradiscal catheter (Spine-CATH; Oratec Interventions, Menlo Park, CA). Temperatures were recorded in the nucleus (TN) and the posterior annulus (TPA). The spines were harvested at predetermined intervals up to 18 months. Histologic sections of the discs were graded for disc morphology to assess degeneration and immunohistochemical staining to assess potential denervation. RESULTS: Vascular granulation tissue consistent with a healing response was observed in the posterior annular tear of all incised discs from 12 weeks. Protein gene product 9.5 (PGP 9.5) positive nerve fibers were clearly identified in the adjacent periannular tissue and the outer few lamellae of the posterior annulus. During the IDET procedure, the mean maximum TPA was 63.6C and the mean maximum TN was 67.C.At sacrifice, the number of nerve fibers identified in the posterior annular tear was the same for those specimens that had undergone IDET and those that had not. From 6 weeks after IDET, there was evidence of thermal necrosisin the inner annulus and adjacent nucleus but sparing the periphery of the disc. CONCLUSIONS: Vascular granulation tissue and posterior annular neo-innervation was observed in the experimentally induced posterolateral annular lesion. IDET delivered at 90C in the sheep consistently heated the posterior annulus and the nucleus to a temperature normally associated with coagulation of nociceptors and collagen contraction. IDET did not denervate the posterior annular lesion. Thermal necrosis was observed within the inner annulus and adjacent nucleus from 6 weeks after IDET. The reported benefits from IDET appear to be related to factors other than denervation and repair.

Animals↗