Biomedical subjects

J E Boyer

Publications and source records attributed to J E Boyer.

11 recordsLinked to original sources

PubMed2003

Mechanical measures of uncooked beef longissimus muscle can predict sensory panel tenderness and Warner-Bratzler shear force of cooked steaks.

Two experiments were conducted to investigate mechanical measures of tenderness on uncooked USDA Select longissimus muscle as a means to predict Warner-Bratzler shear force (WBSF) and trained sensory panel tenderness (SPT) of cooked steaks. In Exp. 1, strip loins (n = 24) were aged 14 d postmortem and fabricated into steaks (2.54 cm). Medial, center, and lateral locations within uncooked steaks were evaluated by a plumb bob device and correlated with WBSF and SPT of cooked steaks. In Exp. 2, 24 strip loins were used to evaluate how well plumb bob and needle probe devices used on uncooked steaks predicted WBSF and SPT of cooked steaks. At 2 d postmortem, two steaks were fabricated from the anterior end. One uncooked steak (2.54 cm) was assigned to the plumb bob treatment and the other uncooked steak (5.08 cm) was assigned to needle probe treatment. At 14 d postmortem, one uncooked steak (5.08 cm) was assigned to needle probe treatment, a second uncooked steak (2.54 cm) was assigned to plumb bob treatment, whereas the remaining steaks (2.54 cm) were cooked and evaluated by a trained sensory panel and WBSF device. In Exp. 1, average plumb bob values were negatively correlated (P < 0.05) to average SPT scores (r = -0.48). However, correlations between WBSF and plumb bob values for medial, lateral, and average of all sections were not significant (P > 0.05). In Exp. 2, regression models to predict SPT from needle probe and plumb bob measurements individually taken at 2 d postmortem had R2 of 0.54 and 0.51, respectively. Combining needle probe and plumb bob measurements resulted in an R2 of 0.76; when quadratic terms for both variables were in the model, the R2 was 0.80. Regressing needle probe and plumb bob measurements at 2 d postmortem with WBSF produced R2 values of 0.51 and 0.45, respectively. If linear terms of both probes were combined to predict WBSF, the R2 increased to 0.77. An equation to predict WBSF, including both the linear and quadratic terms of needle probe and plumb bob measurements, resulted in an R2 of 0.84. Using plumb bob and needle probe devices on uncooked longissimus muscle at 2 d postmortem can predict cooked WBSF and SPT of USDA Select Grade steaks at 14 d postmortem.

Aging↗

PubMed2002

Genetic variation in foraging traits among inbred lines of a predatory mite.

Response of predators to herbivore-induced plant volatiles can affect the length of time a predator spends in a prey patch and the probability of a predator finding a new prey patch. Variation in response to herbivore-induced plant volatiles may lead to different foraging decisions among individuals, thereby affecting both within-patch dynamics and between-patch dispersal. We found significant phenotypic and additive genetic variation in two behavioral assays of response to herbivore-induced plant volatiles among inbred isofemale lines of the predatory mite, Phytoseiulus persimilis. In wind-tunnel tests to measure patch residence time, adult female predators from certain lines left prey patches sooner than others when a distant source of herbivore-induced plant volatiles was presented; whereas such variation disappeared when no distant volatiles were presented. In a measure of patch location, certain lines were more likely than others to locate a prey-infested leaf disc; again there was no difference when uninfested leaf discs were used. Patch location was negatively correlated with patch residence. That is, lines that were more likely to leave a prey patch in the presence of distant volatiles were also more likely to find an odor source (ie, prey patch) from a distance of 20 cm. These two foraging-related behaviors are heritable. A continuous distribution of both behaviors indicated that several to many loci may be responsible for these behavioral traits. Our line-crossing experiments suggested that maternal influence could be excluded. Substantial phenotypic variation in two other foraging-related traits, consumption and oviposition, were also detected among inbred lines. Consumption and oviposition were positively correlated; however, the relationship (slope) varied among inbred lines, suggesting that predatory mites vary in food conversion efficiency. A relationship was detected between patch residence and consumption. Patch location, as one important foraging trait, appeared to be negatively related to consumption, suggesting a trade-off between searching for patches and reproduction.

Animals↗

PubMed1999

The basics of high-performance supplier certification.

Certification of supplier generally means that the supplier provides acceptable quality, on-time delivery at the lowest cost. Companies have devised numerous methods, criteria, formats, and approaches to certifying suppliers. Many of these are too complicated, not understandable, administratively difficult, or fail to be objective. If you have struggled with how to fashion a supplier certification program and how to have suppliers effectively embrace your program, this article is for you. It describes how to reduce the requirements to simple one-page format; details; three basic measures of performance that deal with quality, delivery, and cost; and provides several measurement-driven improvement actions. Supplier certification provides a simple, objective, mutually beneficial method of achieving high-quality, on-time delivery at the lowest cost.

Certification↗

PubMed1998

Steam pasteurization of commercially slaughtered beef carcasses: evaluation of bacterial populations at five anatomical locations.

A steam pasteurization process (patent pending) has been shown to effectively reduce pathogenic bacterial populations on beef tissue and to significantly reduce naturally occurring bacterial populations on commercially slaughtered beef carcasses. The objective of this study was to determine the effectiveness of the steam pasteurization treatment for reducing bacterial populations at several anatomical locations on commerically slaughtered carcasses. Before and after pasteurization treatment (82.2 degrees C, 6.5-s exposure time), a sterile sponge was used to sample 300 cm2 at one of five locations (inside round, loin, midline, brisket, or neck). Eighty carcasses (40 before treatment and 40 after treatment) were sampled per anatomical location over 2 processing days. Before treatment, aerobic plate counts (APCs) were found to be highest (P < or = 0.01) at the midline (4.5 log10 CFU/100 cm2), intermediate at the inside round, brisket, and neck (ca. 3.8 log10 CFU/100 cm2), and lowest at the loin (3.4 log10 CFU/100 cm2). After treatment, APCs at all locations were reduced significantly (P < or = 0.01). The inside round, loin, and brisket had the lowest (P < or = 0.01) APCs (ca. 2.6 log10 CFU/100 cm2), whereas the midline and neck had APCs of 3.1 and 3.3 log10 CFU/100 cm2, respectively. The lower reduction in APCs at the neck area indicated that the treatment may not be as effective there, possibly because of the design of the pasteurization equipment. Generic Escherichia coli populations were low at all locations before treatment, with populations on 32% of all carcasses sampled being less than the detection limit of the study (5.0 CFU/100 cm2). After treatment, E. coli populations were significantly lower (P < or = 0.01) than populations before treatment and 85% of all carcasses sampled had E. coli populations below the detection limit. The maximum E. coli population detected after treatment was 25 CFU/100 cm2. For enteric bacterial populations, no differences were observed in the effectiveness of the treatment among the five carcass locations.

Abattoirs↗

PubMed1994

Techniques for estimating on-animal populations of Ctenocephalides felis (Siphonaptera: Pulicidae).

Effectiveness of two sampling techniques to estimate cat flea populations were compared on beagles (short-haired dogs). Overall, 23.5 and 81.6% of known flea populations on the beagles were detected using area and comb counting techniques, respectively. Using comb counts, we were able to differentiate among beagles that were infested experimentally to produce densities of 21.6 (low), 42.2 (medium), and 82.5 (high) fleas per dog. Using the area counting technique, we were able to differentiate between the medium and high flea population groups, but not the low- and medium-density groups. A weighted regression analysis gave prediction intervals for flea densities that provided satisfactory estimates of the actual numbers of fleas on the dogs.

Animals↗

PubMed1991

Cyclic AMP mediates the direct antiproliferative action of mismatched double-stranded RNA.

Previous experiments have demonstrated that double-stranded RNAs (dsRNAs) can exert an antiproliferative effect on human tumor cells, independent of interferon (IFN) induction. However, the mechanism by which dsRNAs inhibit tumor growth has not been elucidated. As a first step in determining the molecular events responsible for growth arrest, we have explored the role of signal transduction through the cAMP system in the antiproliferative effect of the mismatched dsRNA, r(I)n.r(C12,U)n (Ampligen). These studies utilized the human glioma cell line A1235, which does not produce detectable levels of IFN-alpha, -beta, or -gamma in response to mismatched dsRNA treatment. Treatment of A1235 cells with mismatched dsRNA in combination with either 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), which inhibits cAMP-dependent protein kinase and protein kinase C, or N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA1004), which preferentially inhibits the cAMP-dependent protein kinase, yielded an antagonism of the mismatched dsRNA-induced antiproliferative effect. Measurement of adenylate cyclase activation showed a dose-dependent increase in activity at antiproliferative mismatched dsRNA concentrations, but not at lower, nonantiproliferative doses. This increase in activity was rapid, seen as early as 30 sec after initiation of treatment, and it was sustained at peak levels for 1-2 hr. Analysis of the intracellular cAMP concentration gave similar kinetics of induction. Exposure of cells to the stable cAMP analogue dibutyryl cAMP yielded dose-dependent inhibition of cell growth. The cAMP phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine also inhibited proliferation. In contrast, neither H-7 nor HA1004 had an effect on growth inhibition induced by human natural IFN-alpha treatment. In addition, antiproliferative doses of IFN-alpha did not increase cAMP concentrations. These results indicate that the cAMP system is utilized by mismatched dsRNA as an early signal transduction mechanism for growth control. Furthermore, the antiproliferative effects induced by mismatched dsRNA and IFN can occur by different mechanisms of action.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1987

Ruminal microbial development in conventionally or early-weaned calves.

Eight bull calves (four Holsteins and four Ayrshire calves with mean birth weight of 38.8 kg) were ruminally cannulated at 3 d of age and allocated to one of two weaning programs. All calves were fed colostrum for 3 d after birth and milk until weaning. Calves in the conventional-weaning program were fed a starter diet from 3 d of age and weaned at 6 wk of age. In the early-weaning program, calves were fed a highly palatable pre-starter diet from 3 d of age until they consumed 227 g/d, and then fed a mixture of pre-starter (227 g) and starter diet ad libitum. Calves in this group were weaned at 4 wk of age. Ruminal samples were collected at 3 and 7 d, then weekly thereafter through 8 wk and at 10 and 12 wk of age to assess microbial activity. Calves in the early-weaned group had a higher concentration of total ruminal volatile fatty acids at an earlier age than the calves in the conventional-weaning program. This was accompanied by a trend toward higher lactate concentrations and lower ruminal pH in the early-weaned group during their first 4 wk of age. Lactate and ammonia concentrations decreased with calf age. The total anaerobic bacterial counts increased slightly with calf age, whereas Streptococcus bovis and facultative bacterial populations decreased with calf age. Amylolytic, proteolytic, lactobacilli, lactate-utilizers, cellulolytic and methanogenic bacterial populations increased progressively in both groups. Cellulolytic and methanogenic bacteria were present in both groups at 3 d of age. No protozoa were detected in calves of either group. In general, the most significant changes in bacterial populations and metabolic activity in both groups occurred between 4 and 6 wk of age. Although calves in both groups had similar patterns of bacterial development, calves in the early-weaning program tended to have high ruminal microbial activity at an earlier age than the conventionally weaned calves.

Animals↗

PubMed1987

In vitro lactic acid inhibition and alterations in volatile fatty acid production by antimicrobial feed additives.

Batch culture fermentations were used to determine the effects of avoparcin, lasalocid, monensin, narasin, salinomycin, thiopeptin, tylosin, virginiamycin, monensin + tylosin combination, and two new ionophore compounds (RO22-6924/004 and RO21-6447/009) on lactic acid and volatile fatty acid (VFA) production. Ruminal fluid from cattle fed a high alfalfa hay diet was incubated with glucose for 12 h in a buffered medium to determine the effect of antimicrobial compounds on lactic acid concentration. Fermentations treated with antimicrobial compounds had higher final pH and lower L(+) lactic acid concentration. Narasin and salinomycin were more inhibitory than other ionophore compounds. Monensin and tylosin in combination was more effective than monensin alone. Among the nonionophore compounds, avoparcin was the least effective and thiopeptin, tylosin and virginiamycin were extremely effective in reducing lactic acid concentration. Ruminal fluid from cattle fed a diet of alfalfa hay and grain (50:50) was incubated with a mixture of sugars, casein and urea for 12 h in a buffered medium to determine the effect of antimicrobial compounds on VFA production. Generally, total VFA concentration was not affected by antimicrobial compounds except RO22-6924/004, tylosin and virginiamycin, which caused a reduction at high concentrations. Tylosin, monensin and tylosin mixture, thiopeptin and virginiamycin at high concentrations (greater than 6.0 micrograms/ml) increased the acetate proportion. All compounds increased the molar proportion of propionate. Tylosin and virginiamycin at high concentrations (greater than 6.0 micrograms/ml) decreased the proportion of propionate. Monensin and tylosin in combination had no effect on propionate proportion. Among the compounds tested, narasin and salinomycin were the most effective in enhancing propionate proportion. Ionophore compounds were more inhibitory to butyrate production than the nonionophore compounds. Batch culture fermentations may be used to quantitate the relative efficacy of antimicrobial compounds to alter ruminal fermentation characteristics.

Animals↗

PubMed1986

Rumen microbial changes in cattle fed diets with or without salinomycin.

Four rumen-fistulated steers, randomly assigned to two groups (control and salinomycin fed) were used to monitor the changes in rumen microbial populations and volatile fatty acids (VFA) concentrations associated with feeding salinomycin (0.22 mg X kg-1 X day-1). Steers were adapted to an alfalfa hay and grain (80:20) diet before supplementing the diet with salinomycin, and then the diet was changed to 50:50 and 20:80 ratios of alfalfa hay to grain at 2-week intervals. Rumen samples for total and selective enumeration of anaerobic bacteria. VFA analysis, and enumeration of protozoa were collected during the 80:20 alfalfa hay-to-grain diet before salinomycin feeding, and during the 80:20, 50:50, and 20:80 hay-to-grain diets with salinomycin. At each sampling period, rumen samples were collected at 3 h after feeding on three consecutive days. Salinomycin feeding had no effect on rumen pH and total VFA concentration. The acetate-to-propionate ratio was significantly lower in salinomycin-fed steers than in the control. The molar proportion of butyrate increased in both control and salinomycin-fed steers. Total anaerobic bacterial counts were lower in salinomycin-fed steers than in the control steers after 8 weeks of salinomycin feeding. Salinomycin-resistant bacteria increased from 7.6 to 15.6% in salinomycin-fed steers but remained unchanged in control steers. Salinomycin had no effect on cellulolytic and lactate-utilizing bacteria, but the proportion of amylolytic bacteria was higher in salinomycin-fed steers than in control steers. The total number of protozoa decreased initially in salinomycin-fed steers. The initial reduction was due to reduced numbers of Entodinium species. Holotrichs were unaffected by salinomycin feeding.

Animal Feed↗

PubMed1976

Impregnated disk method for antifungal antibiotic testing.

Sixteen clinical fungal isolates were tested for antibiotic susceptibility by using disks impregnated with growth medium and antibiotic. The procedure was easier to perform, less time consuming, and as reliable as other currently available methods.

Antifungal Agents↗

PubMedDate not supplied

Comparison of stainless steel fascial staples and polypropylene suture material for closure of the linea alba in dogs.

Five centimeter segments of the linea alba in mature, female, mixed breed dogs were incised and then approximated with either stainless steel fascial staples or size 0 polypropylene suture material. Breaking strength of the linea alba closures was determined at 0 (Phase I, 18 dogs) and at 7, 14, and 31 days (Phase II, 18 dogs). Histology and videointeractive planar morphometry were used to evaluate healing of the linea alba. Breaking strength and histologic and morphometric variables were analyzed statistically using analysis of variance in a split plot design. In a clinical trial, 20 cm linea alba incisions were approximated with stainless steel fascial staples after elective ovariohysterectomy in mature, female, mixed breed dogs (Phase III, eight dogs). The dogs were evaluated at 1, 2, 7, 14, 31, 90, and 180 days. Linea alba incisions approximated with polypropylene suture material were significantly stronger than linea alba incisions approximated with stainless steel fascial staples on day 0. There was no significant difference between breaking strength values, histologic, and morphometric appearance of linea alba incisions closed with stainless steel fascial staples or polypropylene suture material when compared 7, 14, and 31 days after surgery. All of the dogs in the clinical trial appeared to be normal at all evaluation times. Approximation of linea alba incisions with stainless steel fascial staples compares favorably to closure with a simple continuous pattern of polypropylene suture material with regard to breaking strength, clinical, histologic, and morphometric appearance.

Abdominal Muscles↗