Stephen R. Werre

A biomechanical comparison of 3.5 locking compression plate fixation to 3.5 limited contact dynamic compression plate fixation in a canine cadaveric distal humeral metaphyseal gap model.

3.5 locking compression plate (LCP) fixation was compared to 3.5 limited contact dynamic compression plate (LC-DCP) fixation in a canine cadaveric, distal humeral metaphyseal gap model. Thirty paired humeri from adult, large breed dogs were separated into equal groups based on testing: static compression, cyclic compression, and cyclic torsion. Humeral constructs stabilised with LCP were significantly stiffer than those plated with LC-DCP when loaded in static axial compression (P = 0.0004). When cyclically loaded in axial compression, the LCP constructs were significantly less stiff than the LC-DCP constructs (P = 0.0029). Constructs plated with LCP were significantly less resistant to torsion over 500 cycles than those plated with LC-DCP (P<0.0001). The increased stiffness of LCP constructs in monotonic loading compared to constructs stabilised with non-locking plates may be attributed to the stability afforded by the plate-screw interface of locking plates. The LCP constructs demonstrated less stiffness in dynamic testing in this model, likely due to plate-bone offset secondary to non-anatomic contouring and occasional incomplete seating of the locking screws when using the torque-limiting screw driver. Resolution of these aspects of LCP application may help improve the stiffness of fixation in fractures modeled by the experimental set-up of this investigation.

A review of Brucella seroprevalence among humans and animals in Bangladesh with special emphasis on epidemiology, risk factors and control opportunities

Brucellosis is a neglected bacterial zoonotic disease in many countries affecting both humans and animals. The aim of this paper is to review published reports of the seroprevalence of brucellosis in humans and animals (cattle, buffalo, sheep, goats and dogs) in Bangladesh. The prevalence studies are based primarily on the following serological tests: rose bengal plate agglutination test (RBT), plate agglutination test (PAT), tube agglutination test (TAT), mercaptoethanol agglutination test (MET), standard tube agglutination test (STAT), slow agglutination test (SAT), milk ring test (MRT), indirect enzyme-linked immunosorbant assay (I-ELISA), competitive ELISA (C-ELISA) and fluorescent polarization assay (FPA). Seroprevalences of brucellosis were found to be affected by the sensitivity and specificity of serological tests employed. Brucellosis prevalence varied based on occupations of people (2.5-18.6%) and species of animals (3.7% in cattle, 4.0% in buffalo, 3.6% in goats and 7.3% in sheep). The prevalence of brucellosis in humans was reported in livestock farmers (2.6-21.6%), milkers (18.6%), butchers (2.5%) and veterinarians (5.3-11.1%) who have direct contact with animal and its products or who consume raw milk. According to published reports brucellosis does affect people and livestock of Bangladesh. There is an immediate need for a concerted effort to control and eradicate brucellosis from domesticated animals in Bangladesh.

Congenital Infection of Mice with Toxoplasma gondii Induces Minimal Change in Behavior and No Change in Neurotransmitter Concentrations

Abstract: We examined the effect of maternal Toxoplasma gondii infection on behavior and the neurotransmitter concentrations of congenitally infected CD-1 mice at 4 and 8 wk of age when latent tissue cysts would be present in their brains. Because of sex-associated behavioral changes that develop during aging, infected female mice were compared with control females and infected male mice were compared with control males. Only the short memory behavior (distance between goal box and first hole investigated) of male mice congenitally infected with T. gondii was significantly different (P < 0.05) from that of uninfected control males at both 4 and 8 wk by using the Barnes maze test. The other parameters examined in the latter test, i.e., functional observational battery tests, virtual cliff, visual placement, and activity tests, were not significantly different (P > 0.05) at 4 and 8 wk. Concentrations of neurotransmitters and their metabolites (dopamine; 3,4-dihydroxyphenylacetic acid; homovanillic acid; norepinephrine; epinephrine; 3-methoxy-4-hydroxyphenylglycol; serotonin; and 5-hydroxyindoleacetic acid) in the frontal cortex and striatum were not different (P > 0.05) between infected and control mice at 8 wk of age. The exact mechanism for the observed effect on short-term memory in male mice is not known, and further investigation may help elucidate the molecular mechanisms associated with the proposed link between behavioral changes and T. gondii infection in animals. We were not able, however, to confirm the widely held belief that changes in neurotransmitters result from chronic T. gondii infection of the brain.

Effects of body position and clinical signs on L7-S1 intervertebral foraminal area and lumbosacral angle in dogs with lumbosacral disease as measured via computed tomography

OBJECTIVE To measure effects of dog position on L7-S1 intervertebral foraminal area and lumbosacral (LS) angle by means of computed tomography (CT) and determine whether changes in values between positions are associated with clinical signs in dogs with LS disease. ANIMALS 86 dogs examined via a positional CT protocol that included flexion and extension scans of L7-S1. PROCEDURES Archived CT images and medical records were reviewed. Included dogs had good-quality flexion and extension CT scans of L7-S1 and no evidence of fractures, neoplasia, or previous LS surgery. One person who was unaware of CT findings recorded clinical status with regard to 3 signs of LS disease (right or left hind limb lameness and LS pain) at the time of CT evaluation. One person who was unaware of clinical findings measured L7-S1 foraminal areas and LS angles, with the aid of an image-analysis workstation and reformatted parasagittal planar CT images. RESULTS Intraobserver variation for measurements of L7-S1 foraminal area ranged from 6.4% to 6.6%. Mean foraminal area and LS angle were significantly smaller when vertebral columns were extended versus flexed. Percentage positional change in L7-S1 foraminal area or LS angle was not significantly different among dogs with versus without each clinical sign. There was a significant correlation between percentage positional change in L7-S1 foraminal area and LS angle in dogs with versus without ipsilateral hind limb lameness and LS pain. CONCLUSIONS AND CLINICAL RELEVANCE Positional CT is a feasible technique for quantifying dynamic changes in L7-S1 intervertebral foraminal morphology in dogs with LS disease.

Exposure to common quaternary ammonium disinfectants decreases fertility in mice

Quaternary ammonium compounds (QACs) are antimicrobial disinfectants commonly used in commercial and household settings. Extensive use of QACs results in ubiquitous human exposure, yet reproductive toxicity has not been evaluated. Decreased reproductive performance in laboratory mice coincided with the introduction of a disinfectant containing both alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC). QACs were detected in caging material over a period of several months following cessation of disinfectant use. Breeding pairs exposed for six months to a QAC disinfectant exhibited decreases in fertility and fecundity: increased time to first litter, longer pregnancy intervals, fewer pups per litter and fewer pregnancies. Significant morbidity in near term dams was also observed. In summary, exposure to a common QAC disinfectant mixture significantly impaired reproductive health in mice. This study illustrates the importance of assessing mixture toxicity of commonly used products whose components have only been evaluated individually.

Frequency of incomplete urolith removal, complications, and diagnostic imaging following cystotomy for removal of uroliths from the lower urinary tract in dogs: 128 cases (1994-2006)

OBJECTIVE To determine the effectiveness of cystotomy for complete removal of urocystoliths and urethroliths in dogs, the types and frequency of diagnostic imaging performed to verify complete urolith removal, the complications that develop as a result of cystotomy, and predictors of each of these variables. DESIGN Retrospective case series. ANIMALS 128 dogs that underwent a cystotomy for removal of urocystoliths, urethroliths, or both from 1994 through 2006. PROCEDURES The following data were obtained from medical records: sex, body weight, number and locations of lower urinary tract uroliths identified in preoperative and postoperative imaging reports, types of imaging used for urolith detection, number of uroliths recovered during cystotomy, quantitative urolith composition, and major complications attributable to cystotomy. Objective criteria were applied to determine whether a cystotomy failed or succeeded and whether appropriate imaging was performed. Associations between potential prognostic factors and outcomes were statistically assessed. RESULTS Effectiveness of cystotomy could be determined in 44 (34%) dogs, of which 9 (20%) had incomplete removal of uroliths. Appropriate postoperative imaging was performed for only 19 (15%) dogs, of which 8 had incomplete removal. Dogs with both urethroliths and urocystoliths were more likely to have a failed cystotomy than dogs with only urethroliths or urocystoliths. Complications developed in 5 (4%) dogs. CONCLUSIONS AND CLINICAL RELEVANCE Cystotomy was a safe and effective surgical procedure for removal of lower urinary tract uroliths in most dogs. Failure to remove all uroliths occurred in a substantial percentage of patients.

Fecal bacterial diversity of human-habituated wild chimpanzees (Pan troglodytes schweinfurthii) at Mahale Mountains National Park, Western Tanzania

Although the intestinal flora of chimpanzees has not been studied, insight into this dynamic environment can be obtained through studies on their feces. We analyzed fecal samples from human‐habituated, wild chimpanzees at Mahale Mountains National Park, Tanzania, and compared microbial community profiles to determine if members of the same social group were similar. Between July and December 2007, we collected fresh fecal samples from 12 individuals: four juveniles, four adolescents, and four adults, including three parent–offspring pairs. Each sample was analyzed using Terminal‐Restriction Fragment Length Polymorphism of amplified 16S rRNA genes. Twelve different profiles were generated, having between 1 and 15 Terminal‐Restriction Fragments (T‐RFs). Overall, a total of 23 different T‐RFs were produced. Putative assignments of T‐RFs corresponded to the phyla Firmicutes (Clostridia, Bacilli, and Lactobacilli), Bacteroidetes, Tenericutes (Mollicutes Class), Actinobacteria, and Proteobacteria, as well as to uncultured or unidentified organisms. Firmicutes and Bacteroidetes phyla and Mollicutes Class were the most commonly assigned in 11, 8, and 8 of the samples, respectively, with this being the first report of Mollicutes in wild chimpanzees. Principal Components Analysis (PCA) revealed clustering of nine samples, and 80.5% of the diversity was accounted for by three samples. Morisita indices of community similarity ranged between 0.00 and 0.89, with dissimiliarity (<0.5) between most samples when compared two at a time. Our findings suggest that, although phylotypes are common among individuals, profiles among members of the same social group are host‐specific. We conclude that factors other than social group, such as kinship and age, may influence fecal bacterial profiles of wild chimpanzees, and recommend that additional studies be conducted. Am. J. Primatol. 72:566–574, 2010.

Intramedullary Spinal Cord Neoplasia in 53 Dogs (1990–2010): Distribution, Clinicopathologic Characteristics, and Clinical Behavior

BACKGROUND Intramedullary neoplasms of the canine spinal cord are infrequently reported. OBJECTIVE To describe distribution, clinicopathologic characteristics, radiographic findings, and clinical features of canine intramedullary spinal tumors. METHODS Retrospective series of histologically confirmed canine intramedullary spinal tumors. Contingency tables were generated for categorical variables (breed, sex, treatment, pain, chief complaint, localization, histology, imaging, and site). Associations were assessed by Fishers exact, Wilcoxon rank sum test, t-test, and one-way ANOVA. RESULTS Intramedullary spinal cord tumors comprised 16% (53/331) of all tumors of the spinal cord. Primary tumors were diagnosed in 66% (35/53) of cases, with neuroepithelial-origin tumors comprising 51% (18/35) of all primary neoplasms. Intraparenchymal metastases of transitional cell carcinoma and hemangiosarcoma accounted for 66% (6/18 each) of all secondary tumors. Primary tumors were more likely to affect younger dogs. Dogs with intramedullary metastases were most commonly presented for primary myelopathic signs (8/18, 44%). The majority of all tumors (52.8%) occurred in the T3-L3 spinal cord segments. All dogs with cervical neurolocalization had primary tumors. Dogs with metastatic lesions had a shorter duration of clinical signs before presentation, but there was no difference in survival time between dogs with primary as compared with secondary tumors. CONCLUSIONS Intramedullary spinal cord tumors are uncommon. Primary intramedullary spinal cord tumors are more common than secondary intramedullary spinal cord tumors and tend to occur in the cervical spinal cord of younger dogs. Intramedullary metastases occur in older dogs, are rarely asymptomatic, and neurologic dysfunction is a common clinical presentation. Dogs with primary tumors may have a protracted clinical course compared with those with intramedullary metastases.

Risk Factors of Porcine Cysticercosis in the Eastern Cape Province, South Africa

There is a high prevalence of Taenia solium taeniosis/cysticercosis in humans and pigs in the Eastern Cape Province (ECP) of South Africa. The objective of this study was to identify risk factors of porcine cysticercosis in select districts of the ECP. Data were collected in 2003 by interviewing 217 pig producers from the area. Blood samples were collected from 261 of their pigs, which were tested using two enzyme-linked immunosorbent assays (ELISA) for the presence of antibodies to cysticercosis. Frequencies of both owner- and pig-level characteristics were determined. For pig-level analysis, all bivariable and multivariable associations were determined using the surveylogistic procedure of the SAS/STAT® software to accommodate for the intraclass correlation that exists for clusters of pigs within one owner and for clusters of owners within a district. All tests for significance were performed at the α = 0.05 level, and adjusted odds ratios (aOR) and 95% confidence intervals (CI) were determined. Among the respondents, 48% of their households lacked a latrine, 98% slaughtered pigs at home, and 99% indicated that meat inspection services were not available. On bivariable analysis, there was a significant association between porcine infection and district (p = 0.003), breed (p = 0.041) and the absence of a latrine (p = 0.006). On multivariable analysis, the absence of a latrine was the only variable significantly associated with porcine infection (aOR = 1.89; 95% CI = 1.07, 3.35) (p = 0.028). The increased odds of porcine infection with households lacking a latrine contributes to our understanding of the transmission of this parasite in the ECP. Determining and addressing the risk factors for T. solium infection can potentially lower the very high prevalence in humans and pigs in this endemic area.

Ultrasonographic findings of the pancreas in cats with elevated serum pancreatic lipase immunoreactivity.

BACKGROUND Pancreatitis is a common disease in cats that is difficult to diagnose. HYPOTHESIS/OBJECTIVES To determine the sensitivity and specificity of ultrasonographic changes of the pancreas with serum feline pancreatic lipase immunoreactivity (fPLI) as the standard for diagnosis of pancreatitis. ANIMALS 35 cats with clinical signs consistent with pancreatitis with an abdominal ultrasound examination and serum fPLI concentration measured within 3 days of the ultrasound. METHODS Retrospective study: Pancreatic thickness, pancreatic margination, pancreatic echogenicity, and peripancreatic fat echogenicity were evaluated. Sensitivity and specificity were calculated with an elevated serum fPLI concentration indicative of pancreatitis as the standard for diagnosis. RESULTS Serum fPLI was elevated and diagnostic for pancreatitis in 19 of 35 cats. The single ultrasound characteristic with the highest sensitivity was hyperechoic peripancreatic fat at 68% (95% confidence interval = 44-87%), indicating a moderate probability that cats with pancreatitis will have this abnormality on ultrasonographic examination. Specificity was >90% for each of increased pancreatic thickness, abnormal pancreatic margin, and hyperechoic peripancreatic fat. The sensitivity and specificity of ultrasound were 84% (95% confidence interval = 60-97%) and 75% (95% confidence interval = 48-93%), respectively, in cats with elevated serum fPLI indicative of pancreatitis. CONCLUSIONS AND CLINICAL IMPORTANCE The presence of a thick left limb of the pancreas, severely irregular pancreatic margins, and hyperechoic peripancreatic fat in cats with appropriate clinical signs and elevated serum fPLI are highly supportive of pancreatitis.