Bacteriologic and histologic features in mice after intranasal inoculation of Brucella melitensis

OBJECTIVE: To characterize effects of intranasal inoculation of virulent Brucella melitensis strain 16M in mice. ANIMALS: Female Balb/c mice, 6 to 8 weeks old. PROCEDURE: Studies were designed to elucidate gross morphologic lesions, bacterial burden in target organs, and histologic changes in tissues following experimental intranasal inoculation of mice with B melitensis 16M, which could be used to characterize a model for testing vaccine efficacy. RESULTS: Measurable splenomegaly was evident at 3 and 7 weeks after inoculation. A demonstrable increase in splenic colony-forming units (CFU) from infected mice increased over time with increasing dose when comparing inocula of 10(3), 10(4), and 10(5) CFU. Recovery of brucellae from the lungs was possible early in infection with 10(1), 10(3), and 10(5) CFU, but only the group inoculated with 10(5) CFU consistently yielded quantifiable bacteria. At a dose of 10 CFU, few organisms were located in the spleen. Bacteria were recovered up to 140 days after inoculation in mice given 10(3) CFU. At an inoculum of 10(5) CFU, bacterial counts were highest early in infection. Histologic examination of tissues revealed an increase in white pulp and marginal zone in the spleen and lymphohistiocytic hepatitis. CONCLUSION AND CLINICAL RELEVANCE: Changes in the spleen and liver increased with increases in dose and with increased time following intranasal inoculation with B melitensis 16M. Surprisingly, histologic changes were not observed in the lungs of inoculated mice.     

Consumer thresholds for establishing the value of beef tenderness.

In the present study, a national consumer evaluation was conducted for beef tenderness on USDA Select strip loin steaks of known Warner-Bratzler shear (WBS) force values, ranging from tough (> 5.7 kg) to tender (< 3.0 kg), and to assess the monetary value that consumers place on tenderness by determining the average price a consumer would pay for a steak in three tenderness categories. Three supermarkets in each of five metropolitan areas (Baltimore, MD/Washington D.C.; Chicago, IL; Dallas/Fort Worth, TX; Los Angeles, CA; and Lubbock, TX) were selected to represent a wide range of income, education, and ethnicity at each city. Five trained research teams traveled to the cities to collect data during the same 10-d period. Consumers (n = 734; minimum of 15 consumers/panel, three panels/store, three stores/city, five cities) were asked to evaluate samples from each tenderness classification (tender, intermediate, or tough) for overall and tenderness acceptability, overall quality, beef flavor, juiciness, tenderness, how much they would pay for the steak ($17.14, 14.28, or 10.98/kg), if they would pay more than current market price if guaranteed tender, and to estimate the number of meals in a 2-wk period that included beef. The consumers were 52% light beef users, consuming 0 to 8 meals containing beef in 2 wk, 41% heavy beef users (greater than 12 meals/2 wk), and 6% moderate beef users (9 to 12 meals/2 wk). Consumer tenderness acceptability increased as WBS values decreased (P < 0.05). The transition in consumer perception from tender to tough beef occurred between 4.3 and 4.9 kg of WBS based on > or = 86% consumer acceptability. Consumer acceptability for tenderness decreased from 86% at 4.3 kg for a "slightly tender" rating to 59% at 4.9 kg for a "slightly tough" rating. Data from the present study suggested that consumer WBS tenderness values of < 3.0, 3.4, 4.0, 4.3, and > 4.9 kg would result in 100, 99, 94, 86, and 25% customer satisfaction for beef tenderness, respectively. Seventy-eight percent of the consumers would purchase steaks if the retailer guaranteed them to be tender. The retail steak value differences found in this study would result in the opportunity for a premium to be paid for a guaranteed tender (< 3.0 kg WBS value) carcass of $76.26 vs the toughest (> 5.7 kg) classification. A premium of $66.96 could be paid to the tender classification carcasses vs the tough (> 4.9 kg) classification carcasses, and a premium of $36.58 could be paid for the tender classification carcasses vs the intermediate (> 3.0 to < 4.6 kg) classification carcasses. Results from the present study show that consumers can segregate differences in beef tenderness and that consumers are willing to pay more for more-tender beef.     

IMAGING OF A CAT WITH PERIRENAL PSEUDOCYSTS

A 16-year-old, neutered male, domestic short hair cat had abdominal distension and systemic hypertension. Radiography, ultrasonography, excretory urography, and renal scintigraphy were performed to establish the diagnosis and implement appropriate treatment. Bilateral perirenal pseudocysts were confirmed surgically and histopathologically. Following bilateral renal capsulectomy, systemic hypertension decreased and global glomerular filtration rate improved to normal limits. Multiple imaging modalities helped establish the diagnosis and guided implementation of appropriate treatment.     

Multiclonal origin of polyps in Gardner syndrome

Electrophoretic analysis of glucose-6-phosphate dehydrogenase was performed on polyp tissue from three black female patients with Gardner syndrome and who are heterozygous for the A and B forms of this enzyme. Polyp tissues from the three patients displayed the AB phenotype. This finding suggests a multiclonal origin of polyps in Gardner syndrome. Studies of tumors originating from such polyps may provide information about the sequence of cellular events leading to malignant transformation.     

Potential Detection and Deterrence Ranges by Harbor Seals of Underwater Acoustic Harassment Devices (AHD) in the Bay of Fundy, Canada

Abstract.— Underwater acoustic harassment devices (AHDs) are designed to deter seals from attacking fin-fish aquaculture cages. They may also be unintentionally disturbing non-target marine mammals. As the distance from the sound source increases, the rate at which the sound pressure level (SPL) drops per unit distance decreases. This prohibits presenting loud sounds near the cages without also creating sounds that can be detected kilometers away. In situ measurements of the sound fields of two AHDs in the Bay of Fundy, Canada, were made. The distances at which a loud AHD with short duration pulses (1.8 msec, 195 dB re 1 μPa at 1 m) and a quieter AHD with longer pulse durations (>50 msec, 166 dB re 1 μPa at 1 m) would be 80 dB or more above the detection threshold of a harbor seal Phoca vitulina were 10 and 3.5 m, respectively. On a quiet day with no nearby vessel traffic, these AHDs would be clearly detectable by harbor seals at ranges up to 2.9 and 1.3 km, respectively. By increasing the pulse length of the louder AHD to >50 msec, the sound would be more than 80 dB above the seal's detection threshold at 100 m but the sound would also be clearly detectable up to 7.2 km. It is technically possible to produce AHDs that are louder. Using very high amplitude sounds to protect finfish aquaculture cages from seal predation without encountering prohibitively large capital and operating costs may not be feasible.     

Seeking alternatives to probit 9 when developing treatments for wood packaging materials under ISPM No. 15

ISPM No. 15 presents guidelines for treating wood packaging material used in international trade. There are currently two approved phytosanitary treatments: heat treatment and methyl bromide fumigation. New treatments are under development, and are needed given that methyl bromide is being phased out. Probit 9 efficacy (100% mortality of at least 93 613 test organisms) has been suggested as an evaluation criterion for new wood treatments, and is based on fruit fly research. We question requiring probit 9 efficacy for wood pests (insects, nematodes and fungi) and discuss challenges to meeting this requirement. Instead, we suggest a 3‐step, laboratory‐based alternative approach. Step 1 involves laboratory experiments (screening) to estimate the lethal dose for the most tolerant stage of each target pest. We consider each infested piece of wood as an experimental unit, not the individual pests, to avoid pseudoreplication. Step 2 requires replicated experiments (with no survivors) at the estimated lethal dose. We suggest a minimum sample size of 60 experimental units, which achieves 0.95 statistical reliability at the 95% confidence level. Step 3 entails studies under simulated operational conditions using wood samples similar in size to wood packaging material and infested to levels that reflect field conditions.     

Pathology of experimentally-induced, acute toxoplasmosis in macropods

SUMMARY Thirteen Tammar wallabies (Macropus eugenii) were dosed orally with 500, 1000 or 10 000 oocysts of Toxoplasma gondii, as part of a vaccination trial. Eleven animals died of acute toxoplasmosis 9 to 15 days after challenge. The lesions were similar in all animals, consisting of foci of necrosis and inflammation in the intestines, lymphoid tissue, adrenal cortex, heart, skeletal muscle and brain, and severe generalised pulmonary congestion and oedema. Free and intracellular tachyzoites of Toxoplasma were associated with the lesions. The remaining 2 animals had shown no signs of disease when euthanased four months after challenge. Small, focal, non-suppurative inflammatory lesions were seen in brain, heart and skeletal muscle of these animals and chronic Toxoplasma infection was confirmed by mouse inoculation.     

Virus isolation studies in an outbreak of porcine encephalomyelitis.

An outbreak of central nervous system disease affecting young pigs occurred in the fall of 1981 in eastern Ontario. A diagnosis of viral encephalomyelitis was made on pathological grounds and virus isolation studies were subsequently initiated to determine the causative agent. Cultural isolation procedures using several biological systems failed to detect virus in nervous tissues from affected animals. Direct extraction of similar tissues by combined biochemical and biophysical procedures yielded nonenveloped , spherical particles with a diameter of 30 nm and a buoyant density of 1.34 g/mL in CsCl. A tentative diagnosis of enterovirus infection was made on this basis.