Identification of a 47 kDa fibronectin-binding protein expressed by Borrelia burgdorferi isolate B31

The attachment of pathogenic microorganisms to host cells and tissues is often mediated through the expression of surface receptors recognizing components of the extracellular matrix (ECM). Here, we investigate the ability of Borrelia spirochaetes to bind the ECM constituent, fibronectin. Borrelia lysates were separated by SDS-PAGE, transferred to nitrocellulose and probed with alkaline phosphatase-labelled fibronectin (fibronectin-AP). Five of six Borrelia species and four of eight B. burgdorferi sensu lato isolates expressed one or more fibronectin-binding proteins. Borrelia burgdorferi isolate B31 expressed a 47 kDa (P47) fibronectin-binding protein that was localized to the outer envelope based on susceptibility to proteinase K. The interaction of P47 with fibronectin was specific, and the region of fibronectin bound by P47 mapped to the gelatin/collagen binding domain. P47 was purified by affinity chromatography, digested with endoproteinase Lys-C, and the peptide fragments analysed by liquid chromatography/tandem mass spectroscopy. A search of protein databases disclosed that the P47 peptide mass profile matched that predicted for the bbk32 gene product of B. burgdorferi isolate B31. The bbk32 gene was cloned into Escherichia coli, and the ability of recombinant BBK32 to bind fibronectin and inhibit the attachment of B. burgdorferi was demonstrated. The identification of BBK32 as a receptor for fibronectin binding may enhance our understanding of the pathogenesis and chronic nature of Lyme disease.

Activation state of muscle satellite cells isolated from steers implanted with a combined trenbolone acetate and estradiol implant

Muscle satellite cells were isolated from seven yearling steers implanted for 31 d with a combined implant that contained 120 mg of trenbolone acetate (TBA) and 24 mg of estradiol (E2) and from seven nonimplanted, control steers. Implanted steers had a 28% greater ADG and a 23% greater feed efficiency than did nonimplanted steers. Implanted steers had increased (P<.001) circulating IGF-I concentrations on d 6, 14, and 31 after implantation, and circulating IGF-I concentrations in control steers remained constant or decreased (P<.05) at these times. Maximum fusion percentage was greater (P< .005) in satellite cell cultures isolated from implanted steers (ISC cultures) than in satellite cell cultures isolated from control steers (NSC cultures) (72.8% vs 54.8%, respectively). Satellite cell cultures isolated from implanted steers (ISC cultures) also contained a greater (P<.001) number of myotube nuclei than did NSC cultures (7,998 nuclei/cm2 vs 5,150 nuclei/cm2, respectively). After 72 h in culture, the number of cells (corrected for plating density) was 43% greater (P<.05) in ISC cultures than in NSC cultures. [3H]Thymidine incorporation rates per 10(5) cells at 24 and 34 h after plating were greater (P<.05) in ISC cultures than in NSC cultures; however, incorporation rates did not differ at 72 h. These data indicate that TBA + E2 implantation may result in an in vivo activation of muscle satellite cell proliferation that can be detected in cell culture. This activation may play an important role in TBA + E2-enhanced muscle growth.

Anger management style and the prediction of treatment outcome among male and female chronic pain patients

Anger is a prominent emotion experienced by chronic pain patients. Anecdotes suggest that anger predicts poor outcome following multidisciplinary pain programs, but no empirical evidence documents this link. We expected that patient anger expression or suppression would predict poor outcome following a pain program and that gender differences would emerge. Pre- to posttreatment measures of lifting capacity, walking endurance, depression, pain severity and activity level were collected from 101 chronic pain patients. An 'anger expression x gender' interaction was found such that anger expression among males was correlated negatively with lifting capacity improvements. 'Anger suppression x gender' interactions emerged such that anger suppression among males was correlated negatively with improvements in depression and general activities. These effects remained significant after controlling for trait anger. Thus, how anger is managed may exert unique influence on outcomes apart from the effects of mere anger proneness, at least among male pain patients.

rhuIL-2 adjunctive therapy in multidrug resistant tuberculosis: a comparison of two treatment regimens and placebo

SETTING

Low-dose recombinant human interleukin 2 (rhuIL-2) adjunctive immunotherapy in multidrug resistant tuberculosis (MDR-TB) patients.

OBJECTIVE

Evaluation of the effects of daily versus pulse-administered rhuIL-2 compared to placebo.

DESIGN

MDR-TB patients on best available antituberculous chemotherapy received rhuIL-2 for 30 consecutive days (daily therapy), or for 5 days followed by a 9-day 'rest', for three cycles (pulse therapy). Placebo control patients received diluent. The cumulative total dose of rhuIL-2 given to each patient in either rhuIL-2 treatment group was the same. Patient immunologic, microbiologic, and radiologic responses were compared.

RESULTS

The three treatment schedules induced different results. Immune activation was documented in patients receiving daily rhuIL-2 therapy. Numbers of CD25+ and CD56+ cells in the peripheral blood were increased in these patients, but not in patients receiving pulse rhuIL-2 or placebo. In addition, 5/8 (62%) patients receiving daily rhuIL-2 demonstrated reduced or cleared sputum bacterial load while only 2/7 (28%) pulse rhuIL-2 treated and 2/8 (25%) controls showed bacillary clearance. Chest radiographs of 7/12 (58%) patients receiving daily rhuIL-2 indicated significant improvement over 6 weeks. Only 2/9 (22%) pulse rhuIL-2-treated patients and 5/12(42%) placebo controls showed radiologic improvement.

CONCLUSION

Daily low dose rhuIL-2 adjunctive treatment stimulates immune activation and may enhance the antimicrobial response in MDR-TB.

Cognitive and physical capacity process variables predict long-term outcome after treatment of chronic pain

Cognitive-behavioral and physical therapies are incorporated into multidisciplinary chronic pain programs because changes in pain cognitions and physical capacity may represent therapeutic processes that facilitate favorable outcome. Decreases in depression, however, may explain treatment responses more parsimoniously. Measures of pain helplessness, lifting capacity, walking endurance, depression, pain severity, and activity level were collected from 94 chronic pain patients at pre- and posttreatment and at 3- to 6-month follow-up evaluations. Decreases in pain helplessness were linked to pain severity reduction, whereas walking endurance increases were related to improvements in activity levels and downtime even after controlling for effects of depression decreases. Thus, cognitive and physical capacity changes that occur through pain treatment may make unique contributions to long-term outcome.

Differential gene expression in response to adjunctive recombinant human interleukin-2 immunotherapy in multidrug-resistant tuberculosis patients

Administration of low-dose recombinant human interleukin 2 (rhuIL-2) in combination with multidrug chemotherapy to patients with multidrug-resistant tuberculosis (MDR TB) induces measurable changes in in vitro immune response parameters which are associated with changes in the clinical and bacteriologic status of the patients. To determine the molecular basis of these changes, we have used semiquantitative reverse transcriptase-initiated PCR (RT-PCR) and differential display technology. During rhuIL-2 treatment of MDR TB patients, decreased levels of gamma interferon (IFN-gamma) mRNA in peripheral blood mononuclear cells (PBMC) relative to baseline levels were observed. However, at the site of a delayed-type hypersensitivity (DTH) response to purified protein derivative of tuberculin (PPD), the expression of cellular IFN-gamma and IL-2 mRNAs was increased during rhuIL-2 therapy. Levels of other cytokine mRNAs were not significantly affected by rhuIL-2 administration. Using differential-display RT-PCR, we identified several genes expressed at the DTH skin test site which were up- or down-regulated during rhuIL-2 treatment. Cytochrome oxidase type I mRNA was increased in response to rhuIL-2 therapy relative to baseline levels, as was heterogeneous nuclear ribonuclear protein G mRNA. CD63, clathrin heavy chain, and beta-adaptin mRNAs, all of which encode proteins associated with the endocytic vacuolar pathway of cells, were also differentially regulated by rhuIL-2 administration. The differential effects of IL-2 were confirmed in vitro by using PBMC obtained from PPD-positive individuals stimulated with Mycobacterium tuberculosis and IL-2. The differential expression of genes may provide a surrogate marker for leukocyte activation at a mycobacterial antigen-specific response site and for the development of an enhanced antimicrobial response which may result in improved outcomes in MDR TB patients.

Association between long periods without high-speed workouts and risk of complete humeral or pelvic fracture in thoroughbred racehorses: 54 cases (1991-1994)

OBJECTIVE

To determine whether a two-month or longer period without official high-speed workouts (lay-up) is associated with humeral or pelvic fracture in Thoroughbred racehorses.

DESIGN

Reprospective study.

ANIMALS

Thoroughbred racehorses in California that were euthanatized because of a complete humeral or pelvic fracture.

PROCEDURE

Age, sex, activity, number of lay-ups, number of days from a race or official timed workout to fracture, number of days from end of last lay-up to fracture, mean duration of lay-ups, and total number of days in race training were compared between horses with humeral fractures and horses with pelvic fractures. A case-crossover study was used to estimate relative risk for fracture of the humerus or pelvis occurring within hazard periods of 10 and 21 days following lay-up, compared with periods following more regular participation in official racing or timed workout events.

RESULTS

Horses with pelvic fractures were more often female, older, and had 0 or > or = 2 lay-ups. Horses with humeral fractures were typically 3-year-old males that had 1 lay-up. Horses with pelvic fractures had more total days in race training, fewer days from last exercise event to fracture, and a greater number of days from end of last lay-up to fracture than horses with humeral fractures. Return from lay-up was strongly associated with risk for humeral fracture during hazard periods of 10 and 21 days (relative risk = 71 and 45, respectively).

CLINICAL IMPLICATIONS

Risk of humeral fracture may be reduced if horses are cautiously reintroduced into race training after lay-up.

An in vitro investigation of multi-layer bandages

This study compares the elastic properties of a number of different bandages both in the non-sterile condition and after sterilisation by autoclaving at 134-138 degrees C. Results suggest that, although some products can withstand sterilisation, the performance of some elasticated and coated bandages is adversely affected by excessive heat.

Cognitive and physical capacity process variables predict long-term outcome after treatment of chronic pain

Cognitive-behavioral and physical therapies are incorporated into multidisciplinary chronic pain programs because changes in pain cognitions and physical capacity may represent therapeutic processes that facilitate favorable outcome. Decreases in depression, however, may explain treatment responses more parsimoniously. Measures of pain helplessness, lifting capacity, walking endurance, depression, pain severity, and activity level were collected from 94 chronic pain patients at pre- and posttreatment and at 3- to 6-month follow-up evaluations. Decreases in pain helplessness were linked to pain severity reduction, whereas walking endurance increases were related to improvements in activity levels and downtime even after controlling for effects of depression decreases. Thus, cognitive and physical capacity changes that occur through pain treatment may make unique contributions to long-term outcome.

Relationship between race start characteristics and risk of catastrophic injury in thoroughbreds: 78 cases (1992)

OBJECTIVE

To investigate relationships of several racehorse characteristics and race conditions with risk of a catastrophic musculoskeletal injury (CMI) resulting in euthanasia in Thoroughbreds during racing in California in 1992.

DESIGN

Retrospective longitudinal study.

ANIMALS

Thoroughbreds that incurred CMI during racing and all California race entrants in 1992.

PROCEDURE

Necropsy records were reviewed, and race start information was obtained. Incidence risk of CMI/1,000 race entrants was estimated. Relationships between CMI during racing and race-meet, entrant age and sex, race type and length, and racing surface type and condition were evaluated by use of logistic regression.

RESULTS

Incidence risk of CMI was 1.7/1,000 entrants. A higher risk of CMI was found at 2 fair race-meets, with incidence risks of 4.9 and 5.5/1,000 entrants. Risk of injury in male horses was 1.7 times greater than that in female horses, and influence of age on risk depended on race type. Risk of injury for horses 2 to 5 years old was two times greater for claiming horses than for maiden horses. Race length or racing surface type (dirt vs turf) or condition (fast, muddy, yielding) were not significantly associated with risk of CMI.

CLINICAL IMPLICATIONS

Incidence of CMI was similar among 12 of 14 major and fair race-meets and among various race lengths and racing surface types and conditions, whereas incidence of CMI was influenced by entrant age and sex as well as race type. Investigators should consider controlling for age and sex, race-meet, and race type whenever possible in studies of risk of CMI.

Effect of a combined trenbolone acetate and estradiol implant on steady-state IGF-I mRNA concentrations in the liver of wethers and the longissimus muscle of steers

Treatment of lambs (initial BW 28 kg) for 24 d with a combined implant containing 40 mg of trenbolone acetate (TBA) and 8 mg of estradiol (E2) increased ADG 25% (P < .05, n = 8) and feed efficiency 23% (P < .05, n = 2) compared with unimplanted lambs. By d 3 following implantation, sera from wethers implanted with TBA + E2 showed 32% (307 vs 233 ng/mL) increases (P < .001, n = 8) in IGF-I concentration compared with sera from unimplanted wethers. This increase was maintained throughout the entire 24-d study. Steady-state hepatic IGF-I mRNA levels were increased approximately 150% in implanted lambs compared with unimplanted lambs (P < .05, n = 4). These data suggest that liver may be the source of at least part of the increased circulating IGF-I in TBA + E2-implanted sheep. In steers implanted with Revalor-S (120 mg of TBA and 24 mg of E2) for 40 d, the steady-state concentration of IGF-I mRNA in the longissimus muscle was 68% greater than in the longissimus muscle of unimplanted steers (P = .013, n = 4). Consequently, increased local production of IGF-I by muscle tissue may play a role in increasing circulating IGF-I concentrations as well as an autocrine or paracrine role in stimulating muscle growth in steers implanted with Revalor-S.

Preliminary on-road measurement of the effect of oxygenated fuel on CO emissions near Las Vegas, Nevada

A preliminary measurement of an oxygenated fuel effect for in-use vehicles travelling at freeway speed was conducted near Las Vegas, NV, in January 1991 and May 1992. The experimental design was based on two principal factors: (1) the large volume of traffic that visits Las Vegas from Southern California on three-day holiday weekends and (2) the fact that, at the time of the study, the Las Vegas area used oxygenated fuels in the winter and Southern California did not. Measurements were conducted at carefully selected sites 20 km southwest of Las Vegas near Sloan, NV, and were accomplished with the Fuel Efficiency Automoblie Test (FEAT) remote sensor developed at the University of Denver. The January 1991 measurements were made during the Las Vegas oxyfuel season, while the May 1992 control measurements were made outside the oxyfuel season. Over 24,500 individual CO concentrations were measured; registration data from over 5,500 of these vehicles were obtained from the license plate numbers. After corrections for differences in velocity and mean age, the Las Vegas outbound (oxyfuel) CO emissions on Monday morning of the January holiday weekend showed a difference of -18% +/- 11% compared to the inbound (non-oxyfuel) CO emissions on Friday evening preceding the holiday weekend.

A case-crossover study of intensive racing and training schedules and risk of catastrophic musculoskeletal injury and lay-up in California thoroughbred racehorses

The objective of this study was to investigate the relationship between intensive racing and training schedules and risk of either catastrophic musculoskeletal injury (CMI) or lay-up from racing in California Thoroughbreds. Thoroughbred racehorses that sustained a CMI during racing or training and either were subsequently euthanized or died on a California racetrack during 1991 and 1992 were studied using a case-crossover study design. Each study subject (case) provided its own self-matched control information in the form of 'typical' exposure frequency, determined or estimated from historic information. Periods of rapid average daily accumulation of high-speed exercise distance were identified for each horse from official race and training histories with a sliding 60-day window. Those window frames containing an average daily rate of distance accumulation exceeding 75th percentile cutoff values were classified as exposed frames followed by 30 days of increased risk, or hazard periods. All remaining days (excluding periods of layoff from racing) were considered non-hazard time at risk. The relative risk (RR) of CMI within 30 days following a period of rapid accumulation of high-speed exercise distance (during a hazard period) was 4.2 (95% confidence interval [CI] = 3.0, 5.8). Of these 214 cases, 84 (39%) were injured during a hazard period whereas on average only 22% of total career time at risk was hazard time for these horses. A second analysis was performed for horses with at least 1 lay-up period from racing of > or = 60 days. RR for a lay-up beginning during a hazard period was estimated for the last lay-up experienced by each horse. The RR for lay-up beginning during a hazard period was 4.8 (95% CI = 2.9, 8.1). Of these 98 cases, 32 (33%) of the lay-ups began during a hazard period whereas on average, only 22% of at-risk time up to last lay-up was hazard time for these horses.

Culturing selects for specific genotypes of Borrelia burgdorferi in an enzootic cycle in Colorado

In Colorado, Borrelia burgdorferi sensu stricto, the etiologic agent of Lyme disease, is maintained in an enzootic cycle between Ixodes spinipalpis ticks and Neotoma mexicana rats (27). The frequencies of flagellin (fla), 66-kDa protein (p66), and outer surface protein A (ospA) alleles were examined in 71 B. burgdorferi isolates from samples from Colorado. Approximately two-thirds of these samples were isolates from I. spinipalpis ticks that had been cultured in BSK-H medium prior to DNA extraction. The remaining samples were from total DNA extracted directly from infected I. spinipalpis ticks. A portion of each gene was amplified by PCR and screened for genetic variability by single-strand conformation polymorphism (SSCP) analysis. We identified three alleles in the fla gene, seven in the p66 gene, and seven in the ospA gene. Sequencing verified that the amplified products originated from B. burgdorferi template DNA and indicated 100% sensitivity and specificity of the SSCP analysis. The frequencies of the p66 and ospA alleles were significantly different between cultured and uncultured spirochetes. The number of three-locus genotypes and the genetic diversity of alleles at all loci were consistently lower in cultured spirochetes, suggesting that culturing of B. burgdorferi in BSK-H medium may select for specific genotypes.

Duration of tick attachment as a predictor of the risk of Lyme disease in an area in which Lyme disease is endemic

Animal studies have shown an exponential increase in the risk of Borrelia burgdorferi infection after 48-72 h of deer tick attachment. Persons with tick bites were prospectively studied to determine if those with prolonged tick attachment constitute a high-risk group for infection. Ticks were identified, measured for engorgement, and assayed by polymerase chain reaction (PCR) for B. burgdorferi DNA. Duration of attachment was determined from the scutal index of engorgement. Of 316 submissions, 229 were deer ticks; 14% were positive by PCR. Paired sera and an intact tick for determination of duration of attachment were available for 105 subjects (109 bites). There were 4 human cases (3.7% of bites) of B. burgdorferi infection. The incidence was significantly higher for duration of attachment > or =72 h than for <72 h: 3 (20%) of 15 vs. 1 (1.1%) of 94 (P = .008; odds ratio, 23.3; 95% confidence interval, 2.2-242). PCR was an unreliable predictor of infection. Tick identification and measurement of engorgement can be used to identify a small, high-risk subset of persons who may benefit from antibiotic prophylaxis.

Cell-density-dependent expression of Borrelia burgdorferi lipoproteins in vitro

Previously, we had identified non-OspA-OspB surface proteins of Borrelia burgdorferi that are targeted by the antibody-dependent complement-mediated killing mechanism. Here we demonstrate by Western blotting that one of these proteins, P35, is upregulated at the onset of stationary phase in vitro. Northern analysis revealed that the upregulation of P35 is at the level of transcription. In addition, the expression of an open reading frame (ORF) located downstream of the p35 gene was found to be regulated in the same fashion as that of P35. This ORF encodes a 7.5-kDa lipoprotein. The transcriptional start sites for both of these genes were determined, to aid in the identification of the putative promoter regions. Additional sequencing of the 5' flanking region of the p35 gene revealed a region of dyad symmetry 52 bp upstream of the transcription start site. Southern analysis demonstrated that the expression of these genes was not due to a cell-density-dependent rearrangement in the genome of B. burgdorferi. These findings provide an in vitro model for studying mechanisms of gene regulation in B. burgdorferi.

Genetic heterogeneity of Borrelia burgdorferi in the United States

To examine in detail Borrelia burgdorferi strain diversity in the United States, 186 isolates from human, tick, and rodent sources were analyzed from multiple distinct geographic regions of the United States and abroad. Strains were characterized by genomic macrorestriction analysis and ospA and 23S rDNA gene sequencing followed by phylogenetic analysis. Results indicate that spirochetal isolates from the United States fall into two major divisions and nine or more subdivisions; human isolates fell into five of these subdivisions. Greater genetic diversity was observed among B. burgdorferi isolates from moderate climatic regions, consistent with increased tick vector and reservoir diversity. All of the Borrelia isolates were reactive by ospA polymerase chain reaction except for Borrelia hermsii controls and several tick isolates from the Northeast, which were shown to lack the 49-kb plasmid encoding outer surface protein A (OspA). The data suggest that US B. burgdorferi isolates demonstrate substantial genetic heterogeneity, with regional differences in spirochete populations.

Molecular characterization of a 35-kilodalton protein of Borrelia burgdorferi, an antigen of diagnostic importance in early Lyme disease

Antibodies against a 35-kDa antigen of Borrelia burgdorferi are detectable in the serum of about half of patients with early Lyme disease. The gene encoding this antigen was isolated from a genomic library of B. burgdorferi B31 (low passage), and full-length expression of the recombinant gene product was achieved in Escherichia coli. Antiserum raised against the recombinant protein was reactive with a B. burgdorferi protein of the same molecular size as the diagnostic 35-kDa antigen cited in an earlier study of criteria for the sero-diagnosis of early Lyme disease. Also, the recombinant protein was reactive with serum from patients with early Lyme disease who were seropositive for the 35-kDa antigen. DNA sequence analysis of the gene indicated an open reading frame of 909 bp encoding a protein with a calculated molecular mass of 34.3 kDa. This gene did not possess the usual initiation codon ATG but rather probably used a TTG codon. The deduced amino acid sequence of the N terminus exhibited a motif similar to that for signal peptides of lipoproteins. Southern blotting revealed a chromosomal location for this gene; and it was specific for B. burgdorferi, B. afzellii, and B. garinii but not for B. hermsii, B. coriaciae, or B. turicatae.

Encore performance. Discovering new directions in gaming

The use of games as a teaching method for mandatory education programs has increased in popularity in recent years. Games provide a fresh, enjoyable learning experience for content often viewed as relatively dry, boring material. The challenge remains for educators to develop new approaches for learners to maintain interest, enthusiasm, and knowledge of essential content. This article offers a variety of creative approaches that can be utilized to "keep the drive alive" and to continue this effective, efficient, and highly accepted strategy of game use.

Horseshoe characteristics as possible risk factors for fatal musculoskeletal injury of thoroughbred racehorses

OBJECTIVE

To evaluate selected shoe characteristics as risk factors for fatal musculoskeletal injury (FMI) and specifically for suspensory apparatus failure (SAF) and cannon bone condylar fracture (CDY) of Thoroughbred racehorses in California.

DESIGN

Case-control study.

ANIMALS

Thoroughbred racehorses (n = 201) that died of were euthanatized at California racetracks between August 1992 and July 1994.

PROCEDURE

Shoe characteristics were compared between case horses affected by FMI (155), SAF (79), and CDY (41) and control horses that died for reasons unrelated to the appendicular musculoskeletal system (non-FMI; 46). Multivariable logistic regression was used to estimate odds ratios for FMI, SAF, and CDY.

RESULTS

Toe grabs were identified as possible risk factors for FMI, SAF, and CDY. The odds of FMI, SAF, and CDY were 1.8, 6.5, and 7.0, respectively, times greater for horses shod with low toe grabs than for horses shod without toe grabs on front shoes. Horses shod with regular toe grabs on front shoes had odds 3.5, 15.6, and 17.1 times greater (P < 0.05) for FMI, SAF, and CDY, respectively, compared with horses shod without toe grabs. The odds of horses shod with rim shoes were a third (P < 0.05) of those shod without rim shoes for either FMI or SAF. The apparent association between toe grab type and CDY may, in part, be attributable to concurrent SAF and CDY injuries in many horses.

CLINICAL RELEVANCE

Avoiding the use of toe grabs should decrease the incidence of FMI, especially SAF, in Thoroughbred racehorses. The use of rim shoes that are more consistent with natural hoof shape may decrease injury risk.

Serodiagnosis of Lyme disease: accuracy of a two-step approach using a flagella-based ELISA and immunoblotting

An ELISA containing a purified flagellar antigen from Borrelia burgdorferi (FLA-ELISA) was evaluated. The FLA-ELISA, detecting IgM and IgG together, did not have adequate specificity by itself. Good accuracy was obtained, however, when the FLA-ELISA was the first step in a two-step protocol that used immunoblotting as a conditional second test. Samples that scored positive or equivocal by the FLA-ELISA were evaluated with separate IgM and IgG immunoblots. The sensitivity of the two-step process for patients with erythema migrans or with later manifestations of Lyme disease was 64% and 100%, respectively. The specificity for health blood donors was 100% and was 90% for the aggregate of all persons with illness that may cause serologic cross-reactivity (98% if the samples from relapsing fever patients were excluded). Test precision was 96% overall, 99% for Lyme disease case serum samples, 100% for specimens from blood donors, and 88% for samples from persons with other illness.

Postmortem evaluation of homotypic variation in shoe characteristics of 201 thoroughbred racehorses

OBJECTIVES

To develop a standard technique for evaluation of racehorse shoes, to assess homotypic variation (interlimb variation) in shoe characteristics, and to determine whether shoe characteristics varied with age and sex.

DESIGN

Cross-sectional study.

ANIMALS

Thoroughbred racehorses (n = 201) that died or were euthanatized at California racetracks between August 1992 and July 1994.

PROCEDURE

Shoe characteristics were measured on horses examined after death. Percentage of agreement was used to compare shoe characteristics between limbs (homotypic variation). Using chi 2 analysis, shoe characteristics were compared between horses grouped by age and sex.

RESULTS

Toe grabs were present on 90.5% of horses, and rim shoes were present on 15.9% of horses. Heel traction devices were less frequent on front (2.5%) than rear (6%) hooves. Pads were present on 24.9% of horses, with bonded rim pads most common. Special types of shoes were present cn 5% of horses. Percentage of agreement between left and right front hooves and between left and right rear hooves was high (20/25 variables; % agreement > or = 99). In contrast, percentage of agreement between left front and left rear hooves and between right front and right rear hooves was low (2/25 variables; % agreement > or = 99). Presence of a pad was significantly (P < 0.05) associated with age, and several shoe variable (size, presence of a special shoe, overall wear matched) were significantly (P < 0.05) associated with sex.

CLINICAL RELEVANCE

Except for variables related to special shoes, wear, and weight, 1 shoe for the respective fore- or hind limbs could be used as an indicator for the contralateral shoe worn by Thoroughbred racehorses without substantial loss of information. However, 1 shoe could not be used as an indicator for shoe characteristics of all 4 limbs. Some shoe characteristics are associated with age and sex, and these variables should be considered possible confounders in studies of shoe characteristics.

Outer surface protein C (OspC), but not P39, is a protective immunogen against a tick-transmitted Borrelia burgdorferi challenge: evidence for a conformational protective epitope in OspC

Outbred mice were immunized with the soluble fraction of a crude Escherichia coli lysate containing either recombinant outer surface protein C (OspC or P39 of Borrelia burgdorferi B31 (low passage). Following seroconversion, the mice were challenged with an infectious dose of B. burgdorferi B31 via the natural transmission mode of tick bite. Three mice immunized with P39 were not protected; however, all 12 of the recombinant OspC-immunized mice were protected from infection as assayed by culture and serology. Although OspC has been shown to be a protective immunogen against challenge with in vitro-cultured borrelia administered by needle, this study is the first to demonstrate OspC effectiveness against tick-borne spirochetes. Following feeding, all ticks still harbored B. burgdorferi, suggesting that the mechanism of protection is not linked to destruction of the infectious spirochete within the tick. In a separate experiment, groups of four mice were immunized with protein fractions from B. burgdorferi B31 purified by preparative gel electrophoresis in an attempt to identify potential protective antigens. Many of these mice developed high-titer-antibody responses against OspC, but curiously the mice were susceptible to B. burgdorferi infection via tick bite. These results suggest that the protective epitope(s) on OspC is heat sensitive/conformational, a finding which has implications in vaccine development.

Stimulation of circulating insulin-like growth factor I (IGF-I) and insulin-like growth factor binding proteins (IGFBP) due to administration of a combined trenbolone acetate and estradiol implant in feedlot cattle

Objectives of this study were to analyze alterations in circulating IGF-I and insulin-like growth factor binding protein (IGFBP) concentrations due to administration of a combined trenbolone acetate (TBA) and estradiol (E2) implant. This study was part of a larger serial slaughter study in which 64 large-framed (394.1 kg) crossbred steers were randomly assigned to one of four pens. Pens were assigned to one of two treatments: implanted (120 mg of TBA and 24 mg of E2) and nonimplanted. After d 2, 24 steers/treatment remained on the study. These steers were assigned to one of three serial slaughter dates (d 40, 115, and 143). Blood samples were obtained on d 0, 2, 21, 40, 115, and 143 from remaining steers. Serum was harvested and analyzed for IGF-I, IGFBP, and mitogenic activity. Glycyl-glycine (GG) extraction of serum was performed to reduce IGFBP interference in the IGF-I RIA. Implantation with TBA+E2 interference in the IGF-I RIA. Implantation with TBA+E2 increased (P < .001) circulating IGF-I concentrations during the period from d 0 to d 40. On d 21 and 40, steers implanted with TBA+E2 had 16 and 22%, respectively, greater (P < .001) circulating IGF-I concentrations than nonimplanted steers. For steers in the study for at least 115 d, TBA+E2 increased (P < .05) IGF-I concentrations 9, 13, and 19% on d 21, 40, and 115, respectively, compared with nonimplanted steers. Implantation with TBA+E2 resulted in greater (P < .05) serum concentration of a 49/39-kDa IGFBP (IGFBP-3) on d 21 and 40 after implantation. Sera from steers implanted with TBA+E2 stimulated proliferation of cultured muscle satellite cells to a greater extent (P < .05) than did sera from nonimplanted steers on d 21, 40, 115, and 143 after implantation. In summary, TBA+E2 increased serum concentrations of both IGF-I and IGFBP-3. Additionally, implantation increased mitogenic activity of sera from implanted as compared to nonimplanted steers. These alterations may be partially responsible for the positive effects of TBA+E2 implants on feedlot performance and rate of protein accretion in steers.

Effect of a combined trenbolone acetate and estradiol implant on feedlot performance, carcass characteristics, and carcass composition of feedlot steers

Objectives of this study were to determine the influence of trenbolone acetate (TBA) and estradiol (E2) in a combined implant on feedlot performance, carcass characteristics, and carcass composition in finishing steers. Sixty-four large-framed (394.1 kg) crossbred steers were randomly assigned to one of four pens. Subsequently, pens were randomly assigned to one of two treatments, implanted (120 mg of TBA and 24 mg of E2) and nonimplanted. Eight steers/treatment were slaughtered for initial carcass composition. Remaining steers were assigned to one of three serial slaughter dates (d 40, 115, or 143). Implantation increased circulating trenbolone (TBOH) and E2 concentrations throughout the trial. Implantation increased ADG 18% (P < .001) during d 0 to 40, 21% (P < .001) from d 0 to 115, and 16% for the entire 143 d. Implant status had no effect (P > .05) on dry matter intake. Feed efficiency was improved 13% during d 0 to 40 (P < .01) and from d 41 to 115 (P = .07). Longissimus muscle area was larger (P < .05) in implanted steers than in nonimplanted steers on d 115. Carcasses from implanted steers had a smaller (P < .05) percentage of kidney, pelvic, and heart (KPH) fat on d 143 than those from nonimplanted steers. Carcasses from implanted steers possessed more carcass protein (P < .05) on d 40. Implanted steers had an 82% increase (P < .05) in daily carcass protein accretion during the first 40 d. Implantation increased (P < .01) carcass water but did not affect carcass fat accumulation throughout the feeding period. The combined TBA+E2 implant improved feedlot performance and stimulated carcass protein accretion in feedlot steers.