Effective treatment of severe facial dermatitis in lambs.
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Animals↗
Biomedical subjects
D J Wilson
Publications and source records attributed to D J Wilson.
Multiple intestinal 'loops' provide an in vivo model to analyse multiple mucosal immune responses.
Mucosal immunity plays an important role in preventing disease but the induction of protective mucosal immune responses remains a significant challenge. We describe a novel in vivo model to analyze the induction of multiple mucosal immune responses in the small intestine. A sterile segment of intestine ('intestinal-segment'; 2-3 m long) was surgically prepared in the jejunum of 4-6-month-old lambs. This 'intestinal-segment' was then subdivided into consecutive segments, designated as 'loops' (15-20 cm long), that included a Peyer's patch (PP), or 'interspaces' (15-70 cm long), that lacked a visible PP. All 'loops' were sterile when collected 1-4 weeks post-surgery and there was no macroscopic or histological evidence of altered lymph or blood flow. Flow cytometric analysis of cells isolated from PP, mucosal epithelium (IEL) and the lamina propria (LPL) revealed no significant alterations in the cell populations present in 'loop' tissues. The functional integrity of M-cell antigen uptake in sterile intestinal 'loops' was evaluated by comparing the immune response induced by varying doses of soluble versus particulate porcine serum albumin (PSA formulated in alginate microspheres). A dose-dependent, PSA-specific antibody-secreting cell response was restricted to PP present in 'loops' injected with particulate PSA. These observations suggested that PP present in sterile 'loops' were functional and this conclusion was confirmed by detecting cholera toxin-specific antibody-secreting cells and secreted antibody in PP and intestinal contents, respectively, of immunized 'loops.' Thus, each 'loop' provided an independent site to analyze antigen-uptake and the induction of mucosal immune responses by a variety of antigen or vaccine formulations.
Animal Population Groups↗
A structural role for tryptophan 188 of inducible nitric oxide synthase.
All nitric oxide synthase (NOS) isotypes bear a conserved tryptophan that stacks against the proximal face of the heme cofactor. Recently two hyperactive variants of neuronal NOS were reported in which this residue (W409) was replaced by phenylalanine or tyrosine. We find that mutation of the same residue in the oxygenase domain of inducible NOS (W188) to phenylalanine causes severe destabilization of heme binding. W188F is isolated in a predominantly heme-free state, and axial thiolate ligation to the residual bound heme is unstable. However, W188F is soluble and is expressed at levels comparable to wild type. While circular dichroism spectroscopy demonstrates the loss of some secondary structure, the protein chain is not completely denatured and it retains much of its fold between pH 7.5 and 4. This proximal tryptophan of NOS represents a case where a residue is conserved within an enzyme family but for distinct purposes that are isotype-dependent.
Amino Acid Substitution↗
Chronic inflammatory bowel disease of growing sheep.
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Age Factors↗
Identification of differentially expressed genes in hepatocellular carcinoma and metastatic liver tumors by oligonucleotide expression profiling.
BACKGROUND: The characterization of differentially expressed genes between cancerous and normal tissues is an important step in the understanding of tumorigenesis. Global gene expression profiling with microarrays has now offered a powerful tool to measure the changes of thousands of genes in any carcinoma tissues in an effort to identify these key disease-related genes. To compare the gene expression of a primary liver carcinoma, metastatic carcinoma to the liver, and normal liver, the authors analyzed tissue from six primary hepatocellular carcinomas (HCCs), five colorectal adenocarcinoma metastases to the liver, and eight normal livers. METHODS: Samples were processed from total RNA to fragmented cRNA and hybridized onto Affymetrix GeneChip(R) expression arrays. Analyses were performed to determine the consensus pattern of gene expression for primary liver carcinoma, metastatic liver carcinoma, and normal liver tissue and their changes in expression level. RESULTS: In hepatocellular carcinoma, 842 genes were overexpressed, and 393 genes were underexpressed in comparison with genes of normal liver tissue. Of note, 7 of the 20 most increased identified known genes previously have been associated with liver carcinoma or other types of cancers. The 13 additional identified genes until now have not previously shown strong association with cancers. Furthermore, the authors identified 42 genes and 24 expressed sequence tags that are expressed at a significant level in both HCC and metastastic tumors, presenting a list of marker genes indicative of cancerous liver tissue. CONCLUSIONS: In this study, genes that can be involved in the production of and maintenance of hepatic carcinomas were identified. These data offer new insight into genes that are potentially important in the pathogenesis of liver carcinoma, as well as additional targets for new strategies for cancer therapy and treatment.
Adult↗
Outbreaks of clinical mastitis caused by Trichosporon beigelii in dairy herds.
Trichosporon beigelii is widely distributed in nature and is classically associated with white piedra, a mycosis that may involve the hair of the human body. Intramammary infections caused by T beigelii may be fatal in cows; the prevalence in affected dairy herds may be high. Affected cows may have hyperthermia, swelling of the udder, and substantially decreased milk production or agalactia. Intramammary infections caused by yeast, including T beigelii, may also be associated with high bacterial counts in bulk-tank milk.
Animal Husbandry↗
Ultrasound of the shoulder.
Ultrasound of the shoulder is a powerful and accurate method for the examination of the rotator cuff, biceps mechanism and the synovium. This article describes the anatomy, standard examination technique, indications, pitfalls and potential errors. It lists suggested imaging algorithms for a range of shoulder pathology.
Algorithms↗
Dense nonaqueous phase liquid tracer tests: experimental results.
Two dense nonaqueous phase liquid (DNAPL) tracer tests were carried out in a shallow aquifer north of Fort Worth, TX. i-Propanol was used as the nonpartitioning tracer: n-hexanol and n-octanol were the partitioning tracers. Field data, mathematical modeling, the results of column tests, and field tracer tests with NaCl were used in designing the DNAPL tracer tests. The results indicated the presence of DNAPL at both sites tested; semi-quantitative estimates of the amounts of DNAPL present were obtained by mathematical modeling. Interpretation was complicated by heterogeneity of the aquifer and mass transport effects.
Alcohols↗
A study of metabolites as intermediate effectors in angiogenesis.
Metabolites released from hypoxic tissues have been reported as angiogenic factors in circumstances of reduced tissue oxygenation or an increased rate of metabolism. However, in more recent reports their possible role in angiogenesis prior to the induction of hypoxia-inducible genes appears to have been neglected. In a systematic attempt to evalaute their role, metabolites common to the glycolytic and oxidative pathways (nicotinamide adenine dinucleotide, adenosine diphosphate and adenosine triphosphate), exclusively glycolytic metabolites (pyruvate and lactic acid) and exclusively oxidative metabolites (malate, succinate, fumarate and citrate) were tested to assess their effects upon in vivo angiogenesis and in vitro endothelial cell migration and proliferation. In addition, adenosine was tested due to its proposed role in hypoxia-induced angiogenesis. The angiogenic effects in vivo were examined using the chick chorioallantoic membrane assay and in vitro on chick embryonic capillary endothelial cells using a phagokinetic track/migration assay and crystal violet dye binding/proliferation assay. Metabolites common to the glycolytic and oxidative metabolic pathways and exclusively glycolytic metabolites produced an angiogenic response in vivo and in vitro on endothelial cell proliferation and migration, whereas exclusively oxidative metabolites, with the exception of malate, did not. Adenosine caused an increased proliferation of blood vessels in vivo and stimulated endothelial cell migration and proliferation. Overall, these results implicate metabolites as effectors in angiogenesis and it is proposed that they have a role which is possibly independent of the upregulation of hypoxia-inducible genes.
Adenosine↗
Limited magnetic resonance imaging in low back pain instead of plain radiographs: experience with first 1000 cases.
AIM: We report our experience with the first 1000 patients with non-traumatic low back pain (LBP) without radiculopathy undergoing limited sequence magnetic resonance imaging (MRI) instead of plain radiography. METHODS: Between January 1996 and December 1998, 1042 patients with low back pain unresponsive to conservative treatment were examined using a limited MR protocol comprising sagittal T1-weighted and STIR imaging. Plain radiographs were not performed. RESULTS: Malignancy, infection, vertebral fracture, spondylitis, pars defects and cord tumours were detected in 20%. Of the 82 osteoporotic vertebral fractures detected, 51 (62%) were recent and 31 had normal marrow signal indicating that they were old. Eighty pars defects were identified, 45(56%) had spondylolisthesis, 29(37%) were undisplaced and 6 (7%) had pars oedema only. Neoplastic disease was found in 17(8%) of which none was suspected before imaging. Benign neoplastic diseases such as vertebral AVM/haemangiomata were excluded. Twenty-one patients had a variety of disorders including ankylosing spondylitis (7), large vessel aneurysm (3), discitis (2), ovarian cyst (2), sequestered disc (2), sacral insufficiency fracture (2) and one patient each with burst fracture, retroperitoneal haematoma and a previously unsuspected horseshoe kidney. CONCLUSION: The majority of patients with LBP are best assessed clinically and imaging is usually not required. In patients with worrying symptoms, MRI with a limited protocol detects a greater number of abnormalities than previously reported studies using plain radiographs and has replaced plain radiography in our hospital. We report our experience with the first 1000 patients and highlight issues such as protocols, detection rates and communication issues.
Female↗
Enhancement of human osteoblast proliferation and phenotypic expression when cultured in human serum.
Traditionally, culture medium is supplemented with foetal bovine serum (FBS). However, in cultures of osteoblasts intended for human re-implantation, such serum presents potential risks of foreign protein contamination and transmission of viral or prion-related material, if used. We cultured human osteoblasts from 16 patients in 10% autologous human serum, 10% pooled human serum, 10% FBS or 2% Ultroser G. Non-synthetic sera were tested in both heat-treated and non-heat-treated forms. We determined cell growth and osteoblast phenotype. Cell proliferation in all types of human serum was significantly greater than in FBS. This was most marked in heat-treated autologous human serum. Cells cultured in Ultroser G had less proliferation than all other groups. The phenotypic tests showed that cells cultured in human and foetal bovine serum displayed an osteoblast phenotype, with greater protein expression in cells cultured in human serum. We conclude that culture of human osteoblasts in autologous human serum enhances cell proliferation, while maintaining an osteoblast phenotype. These findings have implications for the use of cultured osteoblasts in self-cell therapy. Human osteoblast growth is supported by autologous human serum, which allows re-implantation of cultured cells, while avoiding the risk of foreign protein carry-over with enhancement of cell proliferation.
Aged↗
Primary Ewing sarcoma of the orbit.
PURPOSE: To report the clinicopathologic features of a 17-year-old patient with primary Ewing sarcoma of the orbit. METHODS: The patient was evaluated clinically before surgery with computed tomography scans of the orbit. After surgery, the patient was staged with computed tomography scans and bone scan and was treated with systemic chemotherapy and radiation therapy to the orbit. The orbital biopsy was evaluated with conventional light microscopy and immunohistochemistry. RESULTS: Clinical evaluation revealed proptosis and limited upgaze. Computed tomography scans disclosed a mass involving the superior orbit, anterior cranial fossa, and temporal fossa. Microscopic examination revealed small, poorly differentiated cells with medium-sized nuclei containing finely granular chromatin and small nucleoli. The cytoplasmic borders of the cells were indistinct. A PAS stain revealed modest glycogen in many of the tumor cells. The tumor stained positive for O-13 and vimentin and was negative for neural, skeletal, and lymphoid cell markers. Computed tomography scan, bone scan, and blood chemistries revealed no other site of involvement. After treatment, the clinical symptoms and signs resolved, and there has been no evidence of residual orbital tumor or metastasis. CONCLUSIONS: Primary Ewing sarcoma of the orbit should be considered in the differential diagnosis of children or young adults with proptosis, diplopia, or periorbital swelling. Immunohistochemistry is essential to distinguish Ewing sarcoma from other small round cell tumors.
Adolescent↗
Characterization and analysis of the PikD regulatory factor in the pikromycin biosynthetic pathway of Streptomyces venezuelae.
The Streptomyces venezuelae pikD gene from the pikromycin biosynthetic cluster was analyzed, and its deduced product (PikD) was found to have amino acid sequence homology with a small family of bacterial regulatory proteins. Database comparisons revealed two hypothetical domains, including an N-terminal triphosphate-binding domain and a C-terminal helix-turn-helix DNA-binding motif. Analysis of PikD was initiated by deletion of the corresponding gene (pikD) from the chromosome of S. venezuelae, resulting in complete loss of antibiotic production. Complementation by a plasmid carrying pikD restored macrolide biosynthesis, demonstrating that PikD is a positive regulator. Mutations were made in the predicted nucleotide triphosphate-binding domain, confirming the active-site amino acid residues of the Walker A and B motifs. Feeding of macrolide intermediates was carried out to gauge the points of operon control by PikD. Although the pikD mutant strain was unable to convert macrolactones (10-deoxymethynolide and narbonolide) to glycosylated products, macrolide intermediates (YC-17 and narbomycin) were hydroxylated with high efficiency. To study further the control of biosynthesis, presumed promoter regions from pik cluster loci were linked to the xylE reporter and placed in S. venezuelae wild-type and pikD mutant strains. This analysis demonstrated that PikD-mediated transcriptional regulation occurs at promoters controlling expression of pikRII, pikAI, and desI but not those controlling pikRI or pikC.
Amino Acid Sequence↗
Continuing education needs assessment for on-farm food safety services.
OBJECTIVE: To identify the perceived market or client demand for dairy on-farm food safety services by veterinarians, the need for a food safety continuing education program, and the educational issues that might be addressed in an on-farm food safety curriculum. DESIGN: Survey. STUDY POPULATION: Consulting dairy veterinarians, government veterinarians located in California, and meat packers slaughtering cull dairy cows in California. PROCEDURE: Results of a questionnaire supplied to veterinarians and telephone interviews with meat packer representatives were analyzed by use of univariate and multivariate logistic regression procedures. RESULTS: Some meat packers considered the quality of incoming cull dairy cattle as a control point for food safety hazards. More than 50% of dairy and government-employed veterinarians believed that a current market for on-farm food safety services exists; > 85% believed that a potential market exists. Duration since graduation was negatively correlated with belief in a current market. Government-employed veterinarians were more likely to believe in a current market. Veterinarians were more likely to express a strong interest in offering on-farm food safety services if they believed a current market exists, indicated that they already offer such services, or listed residues and pathogens as the most important issues facing the dairy industry. CONCLUSIONS AND CLINICAL RELEVANCE: Although a potential market for on-farm food safety services is perceived, veterinarians are unsure of their role in this area. new demands of meat packers slaughtering cull dairy cows may be the motivation practitioners need to broach the subject of food safety with clients.
Animals↗
Chorioptic mange in British Suffolk rams.
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Animals↗
A pilot study using magnetic resonance imaging to determine the pattern of muscle group recruitment by rowers with different levels of experience.
OBJECTIVE: To determine whether it was possible using magnetic resonance imaging (MRI) to define the pattern of muscle recruitment in a specific sport (rowing) and to see whether there were differences in this pattern between athletes of different experience. DESIGN AND METHOD: It has been shown that during vigorous exercise the water content of muscle increases transiently. This can be observed using MRI, where the prolonged T2 relaxation time of muscle can be demonstrated. In this study we have exploited the increase in signal seen in exercised muscle on short TI inversion recovery (STIR) sequences, to show how rowers of different experience use different muscle groups. RESULTS: We have shown that trained athletes recruit selected muscle groups to carry out a given task, which they carry out more efficiently than untrained or less experienced athletes. CONCLUSION: We have provided the basis of potential research to refine training methods, in order to develop specific muscle groups in athletes, in the hope of achieving a higher level of performance at an earlier stage in their training. We have also defined a technique that may be of clinical value in cases of muscle dysfunction.
Adult↗
Identification of a cyclohexylcarbonyl CoA biosynthetic gene cluster and application in the production of doramectin.
The side chain of the antifungal antibiotic ansatrienin A from Streptomyces collinus contains a cyclohexanecarboxylic acid (CHC)-derived moiety. This moiety is also observed in trace amounts of omega-cyclohexyl fatty acids (typically less than 1% of total fatty acids) produced by S. collinus. Coenzyme A-activated CHC (CHC-CoA) is derived from shikimic acid through a reductive pathway involving a minimum of nine catalytic steps. Five putative CHC-CoA biosynthetic genes in the ansatrienin biosynthetic gene cluster of S. collinus have been identified. Plasmid-based heterologous expression of these five genes in Streptomyces avermitilis or Streptomyces lividans allows for production of significant amounts of omega-cyclohexyl fatty acids (as high as 49% of total fatty acids). In the absence of the plasmid these organisms are dependent on exogenously supplied CHC for omega-cyclohexyl fatty acid production. Doramectin is a commercial antiparasitic avermectin analog produced by fermenting a bkd mutant of S. avermitilis in the presence of CHC. Introduction of the S. collinus CHC-CoA biosynthetic gene cassette into this organism resulted in an engineered strain able to produce doramectin without CHC supplementation. The CHC-CoA biosynthetic gene cluster represents an important genetic tool for precursor-directed biosynthesis of doramectin and has potential for directed biosynthesis in other important polyketide-producing organisms.
Anthelmintics↗
Ability of anaesthetists to identify a marked lumbar interspace.
Anaesthetists' ability to identify correctly a marked lumbar interspace was assessed in 100 patients undergoing spinal magnetic resonance imaging scans. Using ink, one anaesthetist marked an interspace on the lower spine and attempted to identify its level with the patient in the sitting position. A second anaesthetist attempted to identify the level with the patient in the flexed lateral position. A marker capsule was taped over the ink mark and a routine scan performed. The actual level of markers ranged from one space below to four spaces above the level at which the anaesthetist believed it to be. The marker was one space higher than assumed in 51% of cases and was identified correctly in only 29%. Accuracy was unaffected by patient position (sitting or lateral), although it was impaired by obesity (p = 0.001) and positioning of the markers high on the lower back (p < 0.001). The spinal cord terminated below L(1) in 19% of patients. This, together with the risk of accidentally selecting a higher interspace than intended for intrathecal injection, implies that spinal cord trauma is more likely when higher interspaces are selected.
Adult↗