bluuebunny/crossref_metadata_2025 huggingface dataset:
Postmortem diagnosis of idiopathic hyperammonemia in a horse
Authors: Gilliam Lyndi L. , Holbrook Todd C. , Dechant Julie E. , Johnson Bill J.
Published: March 2008

Abstract A 6‐year‐old Quarter Horse stallion was referred to Oklahoma State University Veterinary Medical Teaching Hospital for evaluation of abdominal pain that developed after breeding activity earlier in the day. The horse developed diarrhea and progressively worsening neurologic signs (circling, ataxia, head pressing) within 22 hours of presentation and was subsequently euthanized due to severe self‐destructive behavior. Antemortem biochemical and hematologic abnormalities included hypocalcemia but no evidence of hepatic disease. Idiopathic hyperammonemia and encephalopathy were suspected; cerebrospinal fluid (CSF) and aqueous humor were collected 10 hours postmortem for ammonia analysis using a colorimetric assay. Results were compared with those of 6 horses that also had been euthanized, for diseases unrelated to encephalopathy. Ammonia also was measured in plasma samples obtained antemortem. Ammonia concentrations in plasma (958 μmol/L), CSF (1566 μmol/L) and aqueous humor (1018 μmol/L) samples from the stallion were markedly increased compared to those in the 6 unaffected horses (plasma, 9–43 μmol/L; CSF, 370–532 μmol/L; aqueous humor, 70–483 μmol/L). Since the acute nature of hyperammonemic encephalopathy often does not provide sufficient time for an antemortem diagnosis, postmortem analysis of CSF and aqueous humor ammonia concentrations may be a useful alternative for documenting hyperammonemia in horses.
Serial blood lactate concentrations in systemically ill dogs
Authors: Stevenson, Connie K. , Kidney, Beverly A. , Duke, Tanya , Snead, Elisabeth C. R. , Mainar‐Jaime, Raul C. , Jackson Marion L.
Published: March 2008

Background: Lactate concentration often is quantified in systemically ill dogs and interpreted based on human data. To our knowledge, there are no published clinical studies evaluating serial lactate concentrations as a prognostic indicator in ill dogs. Objectives: Our objective was to perform a prospective study, using multivariate analysis, to determine whether serial lactate concentrations were associated with outcome in ill dogs requiring intravenous fluids. Methods: Eighty sick dogs had lactate concentrations evaluated, using an analyzer that measures lactate in the plasma fraction of heparinized whole blood, at 0 hours and 6 hours after initiation of treatment. Severity of illness and outcome (survivor, nonsurvivor) were determined by reviewing the patient's record 2 weeks after admission. Lactate concentrations, age, body weight, gender, and severity of illness were evaluated using multivariate analysis to determine their effects on outcome. Results: Dogs with lactate concentrations greater than the reference interval at 6 hours were 16 times (95% confidence interval = 2.32–112.71 times,P< .01) more likely not to survive compared to dogs with lactate concentrations within the reference interval. Lactate concentrations above the reference interval at 0 hours were not significantly related to outcome. However, hyperlactatemia that did not improve by ≥50% within 6 hours was significantly associated with mortality (P= .024). Conclusion: Dogs with a lactate concentration higher than the reference interval at 6 hours were more likely not to survive. These results indicate an association between lactate concentration and outcome and emphasize the importance of serial lactate concentrations in evaluating prognosis.
Measurement of myelin basic protein in the cerebrospinal fluid of dogs with degenerative myelopathy
Authors: Oji, Takashi , Kamishina, Hiroaki , Cheeseman, Jennifer A. , Clemmons Roger M.
Published: March 2008

Background: Analysis of cerebrospinal fluid (CSF) is part of a routine clinical workup in veterinary patients when neurologic disease is suspected. However, knowledge of particular protein markers of disease in CSF is limited. The concentration of myelin basic protein (MBP) in CSF is used as a biochemical marker in humans to evaluate demyelinating lesions in the central nervous system (CNS). Objective: The purpose of this study was to evaluate an ELISA for determination of MBP concentration in the CSF of German shepherd dogs with degenerative myelopathy (GSDM). Methods: Cross‐reactivity of the anti‐human polyclonal antibody used in a commercial ELISA (Active MBP ELISA, Diagnostic Systems Laboratories Inc, Webster, TX, USA) was tested with canine MBP by immunoblotting. CSF samples were collected from both the cisterna magna and the lumbar cistern of 8 clinically healthy control dogs and 8 German shepherd dogs clinically diagnosed with GSDM. MBP concentrations were measured in all CSF samples using the ELISA. Results: The mean MBP concentration in CSF from the lumbar cistern of dogs with GSDM (3.13 ± 0.46 ng/mL) was significantly higher than that in the cisterna magna (0.70 ± 0.06 ng/mL) and from both cisternal (0.47 ± 0.07 ng/mL) and lumbar (0.94 ± 0.37 ng/mL) samples from control dogs. Conclusion: The MBP ELISA has potential as a supplemental test of CSF to diagnose demyelinating disorders in dogs.
CD34+, CD41+acute megakaryoblastic leukemia in a dog
Authors: Suter, Steven E. , Vernau, William , Fry, Michael M. , London Cheryl A.
Published: March 2008

AbstractA clinically normal, 5‐year‐old intact female German Shepherd dog was presented to the local veterinarian to be spayed. Results of a preoperative CBC included mild nonregenerative anemia, severe thrombocytopenia, and 17% unclassified cells. On cytologic examination of aspirates from the dog's enlarged spleen and peripheral lymph nodes, a population of primitive round cells that occasionally resembled megakaryocytes was observed. A bone marrow aspirate specimen was markedly hypercellular with approximately 65% of marrow cells comprising a homogeneous population of immature hematopoietic cells similar to those found in the spleen, lymph nodes, and peripheral blood. Using immunocytochemical stains with canine‐specific antibodies, all neoplastic cells strongly expressed cytoplasmic CD41 and 20–70% of the neoplastic cells expressed CD34 weakly to moderately. Rare (<0.5%) neoplastic cells weakly expressed vWF. The cells were negative for all other markers. Based on these results and the morphology of the neoplastic cells, a diagnosis of acute megakaryoblastic leukemia (AMegL) was made. In spite of treatment, results of a CBC performed 1 week later indicated progressive anemia and thrombocytopenia, and the dog was euthanized. To our knowledge, this report documents the first case of canine AMegL diagnosed with both anti‐canine CD34 and CD41 antibodies.
Phagocytic plasmacytoma in a dog
Authors: Yearley, Jennifer H. , Stanton, Christine , Olivry, Thierry , Dean Gregg A.
Published: March 2008

Abstract A 4‐year‐old neutered male Golden Retriever was presented to the oncology service of the North Carolina State University Veterinary Teaching Hospital for staging of a histiocytic sarcoma of the left forelimb, diagnosed on the basis of biopsies submitted by the referring veterinarian. Cytologic assessment of aspirates of 2 splenic nodules identified on ultrasonographic examination of the abdomen revealed a highly phagocytic population of neoplastic round cells morphologically suggestive of plasma cells. Histologic assessment of the forelimb mass after amputation of the limb revealed a neoplastic round cell population demonstrating extensive cytophagia and erythrophagia. Immunohistochemical analysis of the tumor population revealed it to be negative for BLA.36 with sporadic positivity for lysozyme and CD79a. Immunofluorescent evaluation revealed weak tumor cell positivity for immunoglobulin (Ig) A and IgM, but extensive strong positivity for IgG, confirming the plasma cell origin of the tumor. Although extensive phagocytic activity may strongly suggest histiocytic origin, plasma cell origin must also be considered among the differential diagnoses for phagocytic round cell tumors.
Malignant melanoma in a zebra finch (Taeniopygia guttata): cytologic, histologic, and ultrastructural characteristics
Authors: Irizarry‐Rovira, Armando R. , Lennox, Angela M. , Ramos‐Vara José A.
Published: March 2008

AbstractAn approximately 3‐year‐old adult male zebra finch (Taeniopygia guttata) was diagnosed with malignant melanoma. The large darkly pigmented tumor was located in the coelom, extended from the apex of the heart to the cloaca, and was adherent to the intestines and the ventriculus. Dark small masses (likely metastases) were observed in the lungs. Cytologically, the neoplasm consisted mainly of round to oval cells with brown or pale blue to blue‐brown pigment. Lesser numbers of cells were stellate to dendritic with abundant amounts of brown pigment granules or were markedly pleomorphic with variable amounts of pigment. Histologically, the tumor consisted of dense sheets and aggregates of infiltrative melanocytes that were negative for S‐100 and Melan A. A few cells were consistent with “signet‐ring” melanocytes. Melanocytes examined by electron microscopy contained typical structures, mainly premelanosomes and melanosomes, of this cell type. However, melanocytes with marked pleomorphism also contained intracytoplasmic aggregates of filaments, consistent with previously reported ultrastructural findings in signet‐ring or rhabdoid melanoma of nonavian species.
Establishment of the European College of Veterinary Clinical Pathology (ECVCP) and the current status of veterinary clinical pathology in Europe
Authors: O'Brien P. J. , Fournel‐Fleury C. , Bolliger A. P. , Freeman K. P. , Braun J.‐P. , Archer J. , Paltrinieri S. , Tvedten H. , Polizopoulou Z. S. , Jensen A. L. , Pastor J. , Lanevschi‐Pietersma A. , Thoren‐Tolling K. , Schwendenwien I. , Thoresen S. I. , Bauer N. B. , Ledieu D. , Cerón J. J. , Palm M. , Papasouliotis K. , Gaál T. , Vajdovich P.
Published: March 2008

After 5 years of development, the European College of Veterinary Clinical Pathology (ECVCP) was formally recognized and approved on July 4, 2007 by the European Board of Veterinary Specialisation (EBVS), the European regulatory body that oversees specialization in veterinary medicine and which has approved 23 colleges. The objectives, committees, basis for membership, constitution, bylaws, information brochure and certifying examination of the ECVCP have remained unchanged during this time except as directed by EBVS. The ECVCP declared full functionality based on the following criteria: 1) a critical mass of 65 members: 15 original diplomates approved by the EBVS to establish the ECVCP, 37 de facto diplomates, 7 diplomates certified by examination, and 5 elected honorary members; 2) the development and certification of training programs, laboratories, and qualified supervisors for residents; currently there are 18 resident training programs in Europe; 3) administration of 3 annual board–certifying examinations thus far, with an overall pass rate of  70%; 4) European consensus criteria for assessing the continuing education of specialists every 5 years; 5) organization of 8 annual scientific congresses and a joint journal (with the American Society for Veterinary Clinical Pathology) for communication of scientific research and information; the College also maintains a website, a joint listserv, and a newsletter; 6) collaboration in training and continuing education with relevant colleges in medicine and pathology; 7) development and strict adherence to a constitution and bylaws compliant with the EBVS; and 8) demonstration of compelling rationale, supporting data, and the support of members and other colleges for independence as a specialty college. Formal EBVS recognition of ECVCP as the regulatory body for the science and practice of veterinary clinical pathology in Europe will facilitate growth and development of the discipline and compliance of academic, commercial diagnostic, and industry laboratories in veterinary clinical pathology. Future needs are in developing sponsorship for resident positions, increasing employment opportunities, increasing compliance with laboratory, training, and continuing education standards, and advancing relevant science and technology.
The effect of lead poisoning on hematologic and biochemical values in trumpeter swans and Canada geese
Authors: Katavolos P. , Staempfli S. , Sears W. , Gancz A. Y. , Smith D. A. , Bienzle D.
Published: March 2008

Background: Lead is a persistent contaminant in the environment, and waterfowl are susceptible to lead toxicity from ingestion of lead pellets and fishing weights. Lead affects numerous physiologic processes through inhibition of enzyme activity and protein function, but its effects on commonly assessed avian blood values are incompletely understood. Objectives: Our aim was to evaluate hematologic and biochemical changes associated with blood lead concentrations in trumpeter swans and Canada geese. Methods: Data for CBCs, plasma biochemical profiles (total protein, albumin, glucose, cholesterol, total bilirubin, calcium, phosphorus, gamma‐glutamyltransferase [GGT], aspartate aminotransferase, lactate dehydrogenase, glutamate dehydrogenase, creatine kinase, amylase, and lipase), and whole blood lead concentrations were retrospectively analyzed for 69 trumpeter swans and 52 Canada geese. Laboratory data obtained prospectively from an additional 20 trumpeter swans also were included. RBC morphology was semiquantitated in blood smears from 70 of the birds. Data were analyzed initially by ANOVA and covariance. A statistical model then was constructed to determine the relationship between each parameter and lead concentration. Results: In both avian species, PCV, hemoglobin concentration, and MCHC decreased significantly (P < .05) with increasing blood lead concentration. Uric acid concentration and GGT activity were increased in trumpeter swans and phosphorus concentration was decreased in Canada geese in association with high blood lead concentration (P < .05). Conclusions: Lead toxicosis induced significant changes in the values of commonly measured hematologic parameters in waterfowl. These changes may be useful indicators of severe lead intoxication during routine laboratory assessment. Changes in clinical chemistry values, although statistically significant, were too inconsistent to serve as indicators of lead toxicosis.
Changes in gas composition and acid‐base values of venous blood samples stored under different conditions in 4 domestic species
Authors: Piccione Giuseppe , Bertolucci Cristiano , Grasso Fortunata , Giudice Elisabetta
Published: March 2008

Background: The effect of storage temperature and time on blood gas and acid‐base values has been investigated intensively in cattle and dogs; however, data are lacking in other species.Objective: The aim of our study was to evaluate changes in gas composition and acid‐base values in venous blood stored at different temperatures and for different times in 4 domestic species in Italy. Methods: Blood samples from Comisana sheep (n=10), Maltese goats (n=10), Ragusana donkeys (n=10), and Thoroughbred horses (n=10) were analyzed after storage at 23°C (room temperature) for 15 minutes (group I), 23°C for 1 hour (group II), 37°C for 8 hours (group III), and 4°C for 24 hours (group IV). Results were analyzed using a 1‐way repeated measures ANOVA. Results: In all species no statistically significant differences in pH values were present in samples stored at 4°C for 24 hours. This also was true for Pco2in all species except the horse. Except for HCO3−concentration in the horse, significant changes in Po2, HCO3−concentration, base excess, and the standard bicarbonate concentration were observed for all species in samples stored at 4°C. In samples stored for only 1 hour at room temperature, significant changes in most analytes were detected. Conclusions: The results of this study underline the need for rapid assessment of acid‐base samples, because any delay, even for 1 hour, may affect the results.
Prostatic sarcomatoid carcinoma in a dog: cytologic and immunohistochemical findings
Authors: Pinto da Cunha Nazaré , Ghisleni Gabriele , Romussi Stefano , Caniatti Mario
Published: March 2008

An 8‐year‐old neutered male Boxer was presented with tenesmus, hemorrhagic urethral discharge, and dysuria. Abdominal ultrasound and radiographic examinations revealed irregular prostatic enlargement. Laparotomy was performed and intraoperative cytology was done on imprint smears of a biopsy specimen obtained from a prostatic mass. The cytologic preparation was highly cellular and contained a predominant population of atypical, large, loosely cohesive spindle cells, with rare multinucleated cells and mitotic figures. The cytologic findings were consistent with undifferentiated sarcoma. At necropsy, a large cystic prostatic mass and numerous satellite nodules in the soft tissues around the pelvis were found. On histologic examination the tumor was composed primarily of bundles of neoplastic spindle cells. Rare pseudo‐acinar structures and signet‐ring cells also were observed. On immunohistochemical examination, the neoplastic cells co‐expressed cytokeratin and vimentin. Based on histologic and immunohistochemical findings, the tumor was diagnosed as primary prostatic sarcomatoid carcinoma. This is a rare tumor in dogs, in which biphasic morphology of epithelial and mesenchymal cells can complicate the diagnosis, requiring immunochemical stains for confirmation.
Pure white cell aplasia in a dog
Authors: Weiss Douglas J. , Henson Michael
Published: March 2008

A 3‐year‐old Irish Wolfhound was evaluated because of acute onset of lethargy and fever. Severe neutropenia (0/μL; reference interval 2500–11,200/μL) was associated with granulocyte aplasia in the bone marrow (myeloid:erythroid ratio, 0.009:1). Antineutrophil antibodies were assessed by an indirect immunofluorescence assay using flow cytometry. When normal canine leukocytes were incubated with the patient's serum and anti‐IgG, a marked shift was observed in the forward‐angle light scatter of the neutrophil population, and the monocyte cluster disappeared, possibly the result of fragmentation or lysis. Both neutrophil fluorescence intensity (309 ± 11 median channel units (MCU), control values 107–152 MCU) and the percentage of neutrophils with increased fluorescence intensity (61 ± 5%, control values 3.8–13.7%) were increased in the patient's serum, consistent with the presence of antineutrophil antibodies. Repeated episodes of neutropenia occurred while treatment with steroidal and nonsteroidal immunosuppressive therapy was initiated and modified. The neutrophil count eventually stabilized in the low‐normal range, and the dog was maintained for the next 15 months on prednisone (0.4 mg/kg PO q 48 h) and azathioprine (2 mg/kg daily). During this period, the dog developed immune‐mediated hemolytic anemia and thrombocytopenia, decubital ulcers, nasal aspergillosis, and eventually, multi‐organ septicemia, which led to euthanasia on day 784. A diagnosis of pure white cell aplasia was made in this dog, based on the many similarities to human patients with pure white cell aplasia, including severe neutropenia with selective granulocyte aplasia, serum antineutrophil antibodies, remission dependent on treatment with immunosuppressive therapy, and recurrent bacterial infections.
Cerebrospinal fluid from a dog with hind limb ataxia
Authors: Snyder Laura A. , Tarigo Jaime L. , Neel Jennifer A.
Published: March 2008

A 9‐year‐old spayed female German Shepherd dog with a history of orthopedic disease was presented to the North Carolina State University Veterinary Teaching Hospital for evaluation of recent, progressive, bilateral, hindlimb ataxia. Analysis of cisternal and lumbar cerebrospinal fluid (CSF) samples revealed normal total nucleated cell counts and a mild increase in protein concentration in the lumbar sample. In cytocentrifuged specimens of both CSF samples, aggregates of refractile, angular to irregular, pale blue to colorless, crystalline material were observed in the background. Some of the material appeared birefringent under polarized light. Differentials for the material included contrast agent, epidural anesthetics or other pharmacologic agents, or artifact introduced through sample processing, collection, or handling. Based on investigation of clinical and laboratory processes it was determined that tubes used to collect CSF in the hospital recently had been changed from additive‐free glass tubes to silica‐coated shatter‐resistant plastic tubes (BD Vacutainer Plus serum tubes, silicone‐coated, Becton Dickinson). A cytocentrifuged preparation of saline placed in a silica‐coated tube contained crystalline material identical to that observed in the CSF samples; saline placed in an additive‐free glass tube contained no material. In this case, we document the microscopic appearance of highly concentrated silica particles in cytocentrifuged preparations of CSF and underscore the importance of recognizing and identifying this artifact in cytologic preparations.
Unsteady Entropy Measurements in a High-Speed Radial Compressor
Authors: Mansour M. , Chokani N. , Kalfas A. I. , Abhari R. S.
Published: March 2008

The time-dependent relative entropy field at the impeller exit of a centrifugal compressor is measured. This study is part of a broader effort to develop comprehensive measurement techniques that can be applied in the harsh environment of turbomachines. A miniature unsteady entropy probe (diameter of 1.8 mm) is designed and constructed in the present study. The unsteady entropy probe has two components: a one-sensor fast-response aerodynamic probe and a pair of thin-film gauges. The time-dependent total pressure and total temperature are measured from the fast-response aerodynamic probe and pair of thin-film gauges, respectively. The time-dependent relative entropy derived from these two measurements has a bandwidth of 40 kHz and an uncertainty of ±2 J/kg. The measurements show that for operating Condition A, φ=0.059 and ψ=0.478, the impeller exit flowfield is highly three dimensional. Adjacent to the shroud there are high levels of relative entropy and at the midspan there are low and moderate levels. Independent measurements made with a two-sensor aerodynamic probe show that the high velocity of the flow relative to the casing is responsible for the high relative entropy levels at the shroud. On the other hand, at the midspan, a loss free, jet flow region and a channel wake flow of moderate mixing characterize the flowfield. At both the shroud and midspan, there are strong circumferential variations in the relative entropy. These circumferential variations are much reduced when the centrifugal compressor is operated at operating Condition B, φ=0.0365 and ψ=0.54, near the onset of stall. In this condition, the impeller exit flowfield is less highly skewed; however, the time-averaged relative entropy is higher than at the operating Condition A. The relative entropy measurements with the unsteady entropy probe are thus complementary to other measurements, and more clearly document the losses in the centrifugal compressor.
The Membrane-Proximal External Region of the Human Immunodeficiency Virus Type 1 Envelope: Dominant Site of Antibody Neutralization and Target for Vaccine Design
Authors: Montero Marinieve , van Houten Nienke E. , Wang Xin , Scott Jamie K.
Published: March 2008

Enormous efforts have been made to produce a protective vaccine against human immunodeficiency virus type 1; there has been little success. However, the identification of broadly neutralizing antibodies against epitopes on the highly conserved membrane-proximal external region (MPER) of the gp41 envelope protein has delineated this region as an attractive vaccine target. Furthermore, emerging structural information on the MPER has provided vaccine designers with new insights for building relevant immunogens. This review describes the current state of the field regarding (i) the structure and function of the gp41 MPER; (ii) the structure and binding mechanisms of the broadly neutralizing antibodies 2F5, 4E10, and Z13; and (iii) the development of an MPER-targeting vaccine. In addition, emerging approaches to vaccine design are presented.
Cohesion Group Approach for Evolutionary Analysis of TyrA, a Protein Family with Wide-Ranging Substrate Specificities
Authors: Bonner Carol A. , Disz Terrence , Hwang Kaitlyn , Song Jian , Vonstein Veronika , Overbeek Ross , Jensen Roy A.
Published: March 2008

Many enzymes and other proteins are difficult subjects for bioinformatic analysis because they exhibit variant catalytic, structural, regulatory, and fusion mode features within a protein family whose sequences are not highly conserved. However, such features reflect dynamic and interesting scenarios of evolutionary importance. The value of experimental data obtained from individual organisms is instantly magnified to the extent that given features of the experimental organism can be projected upon related organisms. But how can one decide how far along the similarity scale it is reasonable to go before such inferences become doubtful? How can a credible picture of evolutionary events be deduced within the vertical trace of inheritance in combination with intervening events of lateral gene transfer (LGT)? We present a comprehensive analysis of a dehydrogenase protein family (TyrA) as a prototype example of how these goals can be accomplished through the use of cohesion group analysis. With this approach, the full collection of homologs is sorted into groups by a method that eliminates bias caused by an uneven representation of sequences from organisms whose phylogenetic spacing is not optimal. Each sufficiently populated cohesion group is phylogenetically coherent and defined by an overall congruence with a distinct section of the 16S rRNA gene tree. Exceptions that occasionally are found implicate a clearly defined LGT scenario whereby the recipient lineage is apparent and the donor lineage of the gene transferred is localized to those organisms that define the cohesion group. Systematic procedures to manage and organize otherwise overwhelming amounts of data are demonstrated.
Fe-S Cluster Assembly Pathways in Bacteria
Authors: Ayala-Castro Carla , Saini Avneesh , Outten F. Wayne
Published: March 2008

Iron-sulfur (Fe-S) clusters are required for critical biochemical pathways, including respiration, photosynthesis, and nitrogen fixation. Assembly of these iron cofactors is a carefully controlled process in cells to avoid toxicity from free iron and sulfide. Multiple Fe-S cluster assembly pathways are present in bacteria to carry out basal cluster assembly, stress-responsive cluster assembly, and enzyme-specific cluster assembly. Although biochemical and genetic characterization is providing a partial picture of in vivo Fe-S cluster assembly, a number of mechanistic questions remain unanswered. Furthermore, new factors involved in Fe-S cluster assembly and repair have recently been identified and are expanding the complexity of current models. Here we attempt to summarize recent advances and to highlight new avenues of research in the field of Fe-S cluster assembly.
The cultural context of visual hallucinations
Authors: Knight W D , Fox N C , Rossor M N , Warren J D
Published: March 2008

Visual hallucinations (VH) are a cardinal neuropsychiatric symptom and often have important diagnostic implications. The interpretation of VH is influenced by the patient's social and cultural milieu, but the impact of socio-cultural factors on the interpretation, presentation and detection of VH has been little studied. When patients exhibit VH and other neuropsychiatric phenomena, appropriate sensitivity to the role of cultural factors is an important determinant of the success of the medical consultation. We discuss this issue using three illustrative cases.
Antibiotic-resistant Campylobacter: an increasing problem
Authors: Kent A J , Farouk L , Main J , Hoare J M
Published: March 2008

The case is described of a 27-year-old woman who presented with an acute diarrhoeal illness. She was initially poorly responsive to antibiotics and developed lymphocytic ascites. Diagnosis was difficult to establish, and peritoneal tuberculosis was considered to be the most likely cause of her symptoms. Serological tests eventually confirmed Campylobacter jejuni infection. Campylobacter is one of the most common bacterial diarrhoeal infections, and complications, except for colitis, are rare except in specific disease states—for example, patients with cirrhosis or undergoing peritoneal dialysis. Antibiotic resistance is an increasing problem, and this may potentially lead to a greater incidence of complications in the future.
Detailed Analysis of Sulphate and Nitrate Atmospheric Deposition Estimates at the Turkey Lakes Watershed
Authors: Sirois Alain , Vet Robert J.
Published: March 2008

Daily concentrations of sulphates and nitrates in air and precipitation were measured atthe Turkey Lakes Watershed from September 1980 until December 1984. The measurement data were used to estimate wet, dry, and total deposition of sulphates and nitrates to the watershed. Over the 4 yr, the annual values of total (wet plus dry) deposition ranged from 34 to 38 (± 15%) mmol∙m−2∙yr−1 for SO42− and from 38 to 47 (± 30%) mmol∙m−2∙yr−1 for NO3−. On a molar basis, the deposition of total NO3− exceeded the deposition of total SO42− by 19%. However, when converted to equivalents, total SO42− exceeded total NO3− by 68%. Dry deposition represented approximately 15 and 25% of the total deposition of SO42− and NO3−, respectively, to the watershed. Wet and dry deposition of sulphate and nitrate was found to be highly episodic, with the top 20% of daily events delivering 60–70% of the total sulphur and nitrogen deposition to the watershed. Statistically significant seasonal cycles were found in the concentration and deposition values of most of the sulphur and nitrogen species measured at the watershed.
Distribution of Trace Metals within the Aboveground Phytomass of Acer saccharum Marsh, and Betula alleghaniensis Britt. at the Turkey Lakes Watershed
Authors: Hogan G. D. , Morrison I. K.
Published: March 2008

A study of Mn, Fe, Zn, Cu, Pb, Ni, and Cd distribution in Acer saccharum Marsh, (sugar maple) and Betula alleghaniensis Britt. (yellow birch) was carried out at the Turkey Lakes Watershed (TLW) in the District of Algoma, Ontario. Aboveground phytomass was dominated by stemwood (134 200 kg∙ha−1), stembark (19 300 kg∙ha−1), and branches > 2 cm (38 800 kg∙ha−1). Acer saccharum was the dominant species, accounting for 88% of the aboveground phytomass. The generalized phytomass trace metal concentration series for A. saccharum was Mn > Fe > Zn > Cu > Pb > Ni > Cd and for B. alleghaniensis was Mn > Zn > Fe > Cu > Pb > Ni > Cd. Concentrations of metals were highest in the foliage or stembark and lowest in stemwood but, because of its large mass, stemwood generally contained the greatest amount of metal per tree and per hectare. Components of B. alleghaniensis contained higher Zn and Cd concentrations than did those of A. saccharum by a factor of between 4 and 10, an indication that B. alleghaniensis is an accumulator of these metals. Lead levels in all components were one-third to one-half those reported elsewhere, a reflection of lower deposition at TLW. Historical data from other sites in North America gave no indication that concentrations of essential trace metals in aboveground components were higher than normal for these species.
Fish Community Structure, Biomass, and Production in the Turkey Lakes Watershed, Ontario
Authors: Kelso J. R. M.
Published: March 2008

The Turkey Lakes Watershed contains four lakes, and the headwater lake (Batchawana Lake) consists of two distinct basins, neither of which supports a native, reproducing fish stock. Fish biomass varied by a factor of 3.3 among the other three lakes in the watershed. Fish flesh production varied by a factor of only 1.5 in the system. Salmonid and small cyprinid contribution to biomass and production increased with progression downstream. Both fish biomass and production per unit surface area decreased with increasing lake depth. The fish biomass and production in the watershed was strongly influenced by depth, but alkalinity and phytoplankton carbon assimilation also were related to stock and production. Wishart Lake, immediately below Batchawana Lake, has a fish stock with restricted recruitment, and cyprinids make only a limited contribution to the observed production. Although both these conditions may be symptomatic of lake acidification, it is unclear whether the situation in this watershed results from lake acidification or biogeographic factors.
Risk to Salmonids of Water Quality in the Turkey Lakes Watershed as Determined by Bioassay
Authors: Kwain W. , Kelso J. R. M.
Published: March 2008

Batchawana Lake, the headwater lake in the Turkey Lakes Watershed, was devoid offish. Although a number of factors could cause this fishless state, we conducted in situ studies to partially address conditions related to lake acidification. The spring pH depression did not induce significant, consistent mortality to rainbow trout (Salmo gairdneri) or lake trout (Salvelinus namaycush) caged in situ. In 1981, however, considerable mortality occurred to fish caged in Batchawana Lake during or immediately following the maximum spring pH depression. In the remaining lakes, mortality occurred later in the exposure period. Whole-body concentrations of Na+, Ca2+, and Mg2+ in rainbow trout caged (1980) in three lakes of the watershed were similar; however, K+ appeared slightly higher (but not statistically different) in fish held in the headwater lake. Static bioassays indicated that the 96-h pH-LC50 for brook trout (Salvelinus fontinalis) was 3.80–4.09, considerably lower than the lowest pH, 4.66, observed during spring. Brook trout corralled in Batchawana Lake grew slightly faster and accumulated more Pb and Hg than fish held in a downstream lake. Although pH and trace metal levels in Batchawana Lake may at times be inhospitable to fish, other factors likely contributed to the fishless condition of this lake.
A Study of Metal Accumulation Trends in Sediment Cores from the Turkey Lakes (Algoma, Ontario)
Authors: Morris J. R. , Kwain W.
Published: March 2008

Temporal (vertical) and spatial trends in sediment accumulations of nonresidual aluminum, manganese, lead, zinc, copper, and nickel were investigated in 18 core samples collected from four of the Turkey Lakes in 1980–81. Accumulation rates of nonresidual Al differed among sampling sites, both within and among lakes, but was assumed to have been temporally constant at each location. Concentrations of dry matter and all other metals were expressed as mass per unit mass of Al. Cumulative Al was used as an index of time. Since Mn enrichments near the sediment surface may reflect an oxidation zone, they were not interpreted as increased Mn inputs. Other metal enrichments were considered anthropogenic. Little Pb occurred at the bottom of sediment cores, but Pb accumulation rates increased greatly towards the sediment surface. Major Pb enrichments were assumed to have begun at 1940. Zn accumulation rates had also progressively increased through most of the previous four decades. During the same period, there was a modest rise in Cu and Ni accumulation rates. Metal accumulation rates differed considerably among lakes, and among sites within lakes, but these differences primarily reflected variations in dry matter sedimentation rates.
Loadings of Organochlorine Contaminants and Trace Elements to Two Ontario Lake Systems and Their Concentrations in Fish
Authors: Johnson M. G. , Kelso J. R. M. , George S. E.
Published: March 2008

Direct precipitation contributed > 90% of organochlorine (OC) loadings to Emmett and Bartley lakes and three Turkey Lakes. The OCs with highest lake loadings were PCBs, αBHC, γBHC, methoxychlor, HCB, and dieldrin with means of 31.6, 26.9, 7.2, 1.4, 1.0, and 1.0 μg∙m−2∙yr−1, respectively. Heptachlor epoxide, α- and γ-chlordane, α- and β-endosulfan, endrin, and total DDT had mean loadings of 0.1–0.9 μg∙m−2∙yr−2 mostly from direct precipitation. Heptachlor, aldrin, and mirex were not detected in precipitation, runoff, or fish samples. γBHC, methoxychlor, α- and β-endosulfan, and endrin were not detected in any fish of five species from the five fakes but they had significant lake loadings, in multiple regression analysis, 42–68% of the variability in residues of OCs in fish was accounted for by lake loading and octanol:water partition coefficient (to quantify lipophilicity). Relatively high concentrations of total DDT occurred in fish because of high lipophilicity, high concentrations of αBHC occurred because of high loading, and high concentrations of PCB were attributable to both factors. Trace element loadings in runoff were generally higher than in precipitation to the softwater lakes and lower in the hardwater system. Pb concentrations in fish were proportional to loadings, but Cu and Ni residues in fish were less variable than their loadings, and Zn loadings and residues were relatively uniform. Hg showed highest biomagnification (residue in relation to loading), and the larger piscivorous fish had the highest residues.
Parametric analyses of large truck braking efficiencies
Authors: Hutchinson B. G. , Parker D. J.
Published: March 2008

Simplified braking models are used to analyze the braking efficiencies of a range of truck types under a variety of loading conditions and tire–pavement coefficients of friction. These analyses show that while most of the fully loaded trucks are capable of achieving a braking efficiency of 70%, the braking efficiencies of the unloaded or partially unloaded trucks deteriorate substantially. A bobtail tractor, an unloaded semi-trailer with tridem rear axle group and two air-lift belly axles, and a B-train double trailer with rear trailer unloaded have estimated braking efficiencies of 40–50%. The braking distances required by the unloaded and partially loaded vehicles from a 100 km/h operating speed are two to four times longer than those specified in the Canadian geometric design standards. Comparisons of the model-estimated braking distances with those obtained in one set of field tests show that the models are capable of reflecting accurately observed field behaviour. The results presented in the paper demonstrate the need for a systematic review of those highway design standards that are based on the braking capabilities of vehicles using the highway system. Key words: highway geometric design, truck braking efficiency, braking distances, highway safety.
Fatigue strength of fillet-welded cruciform joints
Authors: Swamidas A. S. J. , Cheema P. S. , Muggeridge D. B.
Published: March 2008

The effect of the cruciform weld profile and internal defects on the stress intensity factor and the crack growth are investigated using a plane stress, linear, elastic, finite element approach. The stress intensity factors and the propagation and total lives of the cruciform joint with or without internal imperfections are determined for various types of analytical modelling and are compared with the published results. In addition, stress concentration factors, stress intensity factors, and fatigue lives are also determined for various ratios of plate thicknesses under tensile and bending loads. Key words: stress intensity factor, cruciform joint, crack growth, crack initiation, fatigue life, fracture mechanics, compact tension specimen, tensile and transverse loads.
Finite element modeling of bolted connections
Authors: Gendron G. , Beaulieu D. , Dhatt G.
Published: March 2008

A finite element model which takes account of plasticity and contact for the behavior of bolted steel connections is presented in this study. The mathematical formulation is first presented, followed by the analysis of two bolted connections and a presentation of the results. Future developments and possible applications are finally described. Key words: steel structures, bolted connections, mathematical model, finite element, nonlinear analysis, plasticity.
Water and sewer service connections in permafrost areas of the Northwest Territories
Authors: Wilson C. E. , Cheema Sukhi
Published: March 2008

Ever since the Government of the Northwest Territories began installing water and sewer service connections in the permafrost areas of the Northwest Territories that are subjected to long and harsh winters, there have been the problems as to how to keep these service connections from freezing. Water and sewere service connections of many types and materials have been installed in permafrost in the Northwest Territories in past years. While not always successful, these have provided invaluable experience and have all contributed to the development of the concept presented in this paper towards the provision of water and sewer connections in the Northwest Territories. This paper presents the current methods for the provision of water and sewer service connections in those communities where the Government of the Northwest Territories is directly responsible for program delivery. The water and sewer service connection details are illustrated in eight concept plans contained in this paper.
Modèles débit–qualité dans un réseau unitaire en période de pluie
Authors: Isabel Denis , Wilson Lucie , Villeneuve Jean-Pierre
Published: March 2008

Several simple quality–discharge models (concentration of suspended matter) are proposed for the atomatic real-time control of combined sewer system overflows. These models are calibrated and verified with data supplied by the City of Québec. They can be useful in setting up a control system which takes into account quality without using real-time measures, since their forecasting capability is interesting even if not perfect. Key words: urban runoff, combined sewer system, quality–discharge model. [Journal translation]
Colonization of abandoned pastures by eastern red cedar (Juniperusvirginiana L.)
Authors: Holthuijzen Anthonie M. A. , Sharik Terry L.
Published: March 2008

Rates and patterns of colonization of the predominantly avian dispersed eastern red cedar (Juniperusvirginiana L.) were investigated in three abandoned pastures in southwest Virginia. The three populations, with median ages of 2, 5, and 14 years, showed sigmoid cumulative net increases in numbers of individuals over time. Exponential increase occurred during the first 6–9 years after initial establishment. Densities peaked in about 8–10 years. Only the youngest population showed a significant spatial gradient in the distribution of red cedar individuals, decreasing exponentially with distance from the nearest cone-bearing trees along the edge of the pasture. A decreasing activity gradient of avian dispersers with distance from the seed source may have influenced a differential seed input in the pasture, resulting in the observed spatial trend in tree density. No relationship existed between age and location of individuals within stands. The apparent spatial uniformity of overall density of individuals with increasing age (as noted in the 5- and 14- year-old populations) is probably due to several factors, including the increasing availability of avian perching sites and the addition of seed sources with increasing age of invading red cedar populations.
Forest soil respiration in eastern Ontario jack pine ecosystems
Authors: Weber M. G.
Published: March 2008

Forest soil respiration insitu was used as a comparative measure of the metabolic activity of substrate in eastern Ontario jack pine (Pinusbanksiana Lamb.) ecosystems that had been exposed to various burning treatments, including wildfire. The five burning treatments consisted of a 1920 wildfire, experimental understorey burning (nonlethal to the overstorey) of this age-class in 1962 and 1963, a 1964 wildfire, and experimental burning of this age-class in 1977. Seasonal respiration trends were similar on all treatments. Carbon dioxide evolution increased in the spring (4000 mg•m−2•d−1) in response to ambient warming (5000 mg•m−2•d−1 in August) and decreased in late fall as seasonal temperatures declined (4000 mg•m−2•d−1 in November). Precipitation and autumnal litter fall apparently acted as secondary modifiers of this general trend by affecting substrate moisture content and nutrient quality, respectively. Highest metabolic activities were measured on the 1963 understorey burning treatment followed in decreasing order by the 1920 wildfire, the 1964 wildfire, the 1962 experimental understorey burn, and the 1977 burn of the 1964 age-class. Multiple comparisons of overall seasonal respiration means revealed lower rates (P < 0.01) on the latter two treatments compared with the 1963 treatment. Effects of understorey burning treatments on respiration activity appeared to depend on depth of burn and subsequent forest floor development. Stand-replacing fire, reoccurring during early stages of jack pine ecosystem development, significantly lowered metabolic activity of the site.
The influence of moisture content and storage temperature on the viability of Shoreaalmon, Shorearobusta, and Shorearoxburghii seed
Authors: Tompsett P. B.
Published: March 2008

Seed of Shoreaalmon Foxw., Shorearobusta Gaertn. f., and Shorearoxburghii G. Don was subjected to desiccation treatments or retained at several different temperatures on 1% agar or in various containers; viability and moisture contents (wet-weight basis) were assessed periodically. Germination ability declined when moisture contents were reduced below approximately 35% for S. roxburghii, below a value exceeding 40% forS. almon, and below 40% for S. robusta; a straight-line relationship was observed between the probit of germination and moisture content percentage. When all three species were kept on agar at 2, 6, or 11 °C little or no germination resulted; on transfer to 26 °C after 153, 54, and 30 days for S. roxburghii, S. robusta, and S. almon, respectively, negligible further germination occurred. Similar chilling damage occurred in S. robusta and S. almon at 16 °C. Mean germination times were twice as long at all temperatures tested for S. roxburghii as they were for the other species. Storage at near 40% moisture content in ventilated containers at 16 °C enabled survival of S. roxburghii seed for 9 months with over 50% viability, whereas other species declined in viability to near 20% within 14 days. A sudden loss of viability within 24 h was observed for seed of S. robusta placed in 11 or 6 °C; in the subsequent few days, little further loss of viability occurred. With 40% moisture content, seeds of all species at 21 °C stored as well as or better than those at lower temperatures. Retention for short periods in closed containers quickly reduced germination for S. robusta and S. almon.
Water relations of white spruce (Piceaglauca (Moench) Voss) at tree line in north central Alaska
Authors: Goldstein Guillermo H. , Brubaker Linda B. , Hinckley Thomas M.
Published: March 2008

Factors affecting xylem pressure potential and stomatal behavior during the growing season were studied on white spruce (Piceaglauca (Moench) Voss) at tree line in the central Brooks Range of northern Alaska. Leaf conductance and xylem pressure potentials were low during days of moderate and high evaporative demand, even though soil moisture was near field capacity. Boundary line diagrams, regression analysis, and laboratory experiments indicate that stomata are sensitive to changes in vapor pressure deficit and xylem pressure potential. A correlation between resistance to water flow through the tree and soil temperature suggests that soil temperatures less than 9 °C are associated with increased resistance to water flow and may partially explain the position of white spruce tree line in northern Alaska.