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co-auteur étranger; International audience; Melt inclusions with large, positive Sr anomalies have been described in multiple tectonic settings, and the origins of this unusual geochemical feature are debated. Three origins have been proposed involving plagioclase as the source of the elevated Sr: (i) direct assimilation of plagioclase-rich lithologies, (ii) recycled lower oceanic gabbro in the mantle source, and (iii) shallow-level diffusive interaction between present day lower oceanic crust (i.e., plagioclase-bearing lithologies) and the percolating melt. A “ghost plagioclase” signature (i.e., a large, positive Sr anomaly without associated high Al2O3) is present in melt inclusions from Mauna Loa. We present new 87Sr/86Sr measurements of individual olivine-hosted melt inclusions from three Hawaiian volcanoes, Mauna Loa, Loihi, and Koolau. The dataset includes a Mauna Loa melt inclusion with the highest reported Sr anomaly (or highest (Sr/Ce)N, which is 7.2) for Hawai'i. All melt inclusions have 87Sr/86Sr values within the range reported previously for the lavas from each volcano. Critically, the 87Sr/86Sr of the high (Sr/Ce)N melt inclusion lies within the narrow range of Mauna Loa melts that lack high (Sr/Ce)N signatures. To explain the high (Sr/Ce)N ratio of the ghost plagioclase signature using an ancient recycled gabbro would therefore require the gabbro-infused mantle source to evolve, by chance, to have the same 87Sr/86Sr as the source of the Mauna Loa melts that lack a recycled gabbro (ghost plagioclase) signature. Alternatively, shallow-level diffusive interactions between Mauna Loa plagioclase-rich cumulates and a percolating mantle-derived melt provides a simpler explanation for the presence of the high (Sr/Ce)N Mauna Loa melts.

Development of a heat-pasteurization process is described for picked meat of Dungeness crabs (Cancer magister) contained in oxygen-impermeable flexible pouches, For each time-temperature treatment, 30 samples, each inoculated with an equal mixture of three strains of C. botulinum nonproteolytic type B, for a total of 107 spores, provided the basis for calculation of the thermal resistance (a 7D process). Following heat processing, the crabmeat was removed from the pouches and transferred to enrichment medium where it was incubated anaerobically for 150 days. Endpoints at which spores survived were determined by the presence of toxin in the enrichment medium. Process times ranged from 90 min at 88.9°C to 20.3 min at 94.4°C. D values (the time at each temperature required to reduce the inoculum by 1 log) ranged from 12.9 for the 88.9°C process to 2.9 for the 94.4°C process. The relative sterilization value, F0 was .054 and the pasteurization value, , was 240. This pasteurization process safely extends refri...

L. monocytogenes was inoculated onto the surface of brined salmon steaks and heat processed in a commercial smokehouse to simulate a hot process for preparing smoked fish. The minimum temperature required for inactivation of L. monocytogenes was 153°F (67.2°C) when generated smoke was applied throughout the entire process. When generated smoke was added only during the last half of the process, L. monocytogenes was recovered from steaks heated to temperatures as high as 176°F (80.0°C). When smoke was not applied during the process, L. monocytogenes survived on steaks heated to internal temperatures between 131°F and 181°F (55.0 to 82.8°C) but was not isolated from steaks heated above 181°F (82.8°C). When liquid smoke CharSol C-10 was applied as a full-strength (100%) dip before processing, L. monocytogenes was inactivated in samples processed at temperatures as low as 138°F (58.9°C). When liquid smoke 10-Poly or CharSol C- 10 was applied at a concentration of 50%, the lethal temperature was increased to the range of 145 to 150°F (62.8 to 65.6°C). With further dilution of C-10 to 25% and 10% the inactivation temperatures increased to 156°F (68.9°C) and 163°F (72.8°C). A full-strength dip of CharOil, the oil-soluble fraction of CharSol C-10. was less effective, and L. monocytogenes survived in salmon steaks processed to an internal temperature of 166°F (74.4°C), the highest temperature tested with this liquid smoke. This study provides evidence that heat alone is not reliable for inactivation of L. monocytogenes during the hot-smoking process. The proper stage and duration of smoke application or proper composition and concentration of liquid smoke in combination with heat are critical for inactivation of the organism.

Comminuted raw salmon containing various concentrations and combinations of sodium lactate, sodium chloride, and sodium nitrite was inoculated with 10 Listeria monocytogenes cells per g (150 cells/15-g sample), vacuum-packaged in oxygen-impermeable film and stored at 5 or 10°C. Samples were examined for growth of L. monocytogenes and total aerobic microorganisms at specific intervals for up to 50 d. Sodium lactate exhibited a concentration-dependent antilisterial effect that was enhanced by nitrite and/or increased concentrations of NaCl. At 5°C, total inhibition of L monocytogenes was achieved for up to 50 d by 2% sodium lactate in combination with 3% water-phase NaCl. At 10°C, total inhibition was achieved for up to 35 d by 3% sodium lactate in combination with 3% water-phase NaCl, or by 2% sodium lactate in combination with 125 ppm sodium nitrite and 3% water-phase NaCl. Sodium lactate and the other additives also inhibited growth of the aerobic microflora but to a lesser degree than L. monocytogenes .

Three selective media were evaluated for direct plating recovery and enumeration of Listeria monocytogenes in the presence of high levels of a variety of microorganisms occurring on cold-process (smoked) salmon products. Sliced salmon was brined to contain either no added salt, 3, or 5% water-phase NaCl, or 3 or 5% NaCl plus 140 ppm NaNO2. The slices were packaged in oxygen-permeable film or sealed under vacuum in oxygen-impermeable film, and stored at 10°C or 5°C until total microbial loads reached 106 to 109 CFU/g. Oxford formulation of Listeria selective agar and Lee's modification of Listeria selective agar achieved quantitative recovery of 102 cells per ml of L. monocytogenes strain Scott A in the presence of diluted slurries of these fish containing 104 to 108 CFU/ml of background organisms. A modification of lithium chloride-phenylethanol-moxalactam agar containing an iron-esculin indicator system sometimes failed because of interfering growth by the background microflora.

This study demonstrates the feasibility of a heat-pasteurization process for certain vacuum-packaged hot-smoked fishery products for inactivation of the spores of the nonproteolytic Group II Clostridium botulinum types B, E, and F. This process permits the use of lower concentrations of salt and other inhibitors without jeopardizing safety and quality of the products during prolonged refrigerated storage. The pasteurization treatment was developed based upon the inactivation of nonproteolytic types B or E in hot-process (smoked) salmon. Smoke was not applied to the samples inoculated with types B and E because of its possible inhibitory effects. After processing in the smokehouse, each sample was cooled to 34°F (1.1°C), injected with 106 spores, vacuum-packaged, and then heat-pasteurized in a water bath held at a constant temperature. A total of 85, 65, and 55 min in the 185°F (85°C), 192°F (88.9°C), and 198°F (92.2°C) baths, respectively, prevented toxin production by type E during 21 d of incubation at 25°C. Longer times, 175, 85, and 65 min, respectively, were required to prevent toxin production by nonproteolytic type B. Toxin production by type E during 120 d of storage at 10°C was prevented by a 45-minute treatment in the 198°F (92.2°C) bath. When heat-pasteurized samples were transferred into TPGY broth and incubated anaerobically for 150 d at 25°C, outgrowth and toxin production by type E was prevented by a 55-minute process at 198°F (92.2°C) and type B was prevented by a 65-minute process. This process does not, however, inactivate the more heat-resistant proteolytic strains of C. botulinum Group I or other spore-formers. The packages and master cartons of these pasteurized products therefore should follow the existing recommendations for smoked fishery products and be labeled "Keep refrigerated - Store below 38°F (3.3°C)."

Whitefish steaks were brined in NaCl, KCl, or equimolar NaCl:KCl to contain similar chloride ion concentration and inoculated intramuscularly with 10 or 100 spores of Clostridium botulinum type E per gram of fish. Steaks were then heated in a simulated (i.e., without smoke) hot-smoke process to internal temperatures of 62.8° to 76.7°C (145°-170°F) for the final 30 min of a 2- to 3-h process, packaged under vacuum in oxygen-impermeable film, and stored at abuse temperature of 25°C. During 7 d of storage, toxin production was inhibited in steaks containing more than 0.66 ionic strength NaCl, 0.64 KCl, or 0.71 equimolar NaCl:KCl. The results indicate that it is feasible to substitute KCl for NaCl in hot-process smoked fish for inhibition of outgrowth and toxin production by Clostridium botulinum type E.

Olivine-hosted melt inclusions from both Fernandina and Santiago islands in the Galapagos Archipelago have compositions indicating that plagioclase played an important role in the magmatic evolution of these volcanic islands.The major and trace element chemistry of the Santiago melt inclusions indicates simple plagioclase assimilation. In contrast, Fernandina inclusions have compositions for which the plagioclase appears to be present only as a ‘ghost’ trace element signature (i.e. ‘ghost plagioclase’signature).Two competing hypotheses have been proposed to explain this unique signature: (1) incorporation of an ancient recycled plagioclase-rich cumulate into the mantle; (2) shallow-level interaction between melts and plagioclase-rich cumulates in the present-day lower oceanic crust. Here we present new Pb isotope measurements for olivine-hosted melt inclusions from Fernandina and Santiago islands to distinguish between the two models.The new Pb isotope data are within the range previously reported for whole-rock basalts from those islands. Melting and mixing models involving ancient ( 0·5^1 Ga) recycled plagioclase-rich cumulates cannot reproduce the observed trace element and Pb isotopic characteristics of the Fernandina melt inclusions with a ghost plagioclase signature. Shallow-level diffusive interactions between basalt and present-day plagioclase-rich cumulates provide the simplest explanation for the observed trace element compositions and Pb isotope ratios of melt inclusions from Fernandina and Santiago islands.

The objectives of this study were to determine which serum thyroid hormone test best identifies iatrogenic hypothyroidism in cats that develop azotaemia after radioiodine treatment and to determine which thyroid test best differentiates these azotaemic, hypothyroid cats from azotaemic, radioiodine-treated euthyroid cats, as well as from azotaemic cats with chronic kidney disease and no history of thyroid disease.A total of 42 hyperthyroid cats that developed azotaemia (serum creatinine ê220 µmol/L) after radioiodine treatment had serum concentrations of thyroxine and free thyroxine by dialysis and thyroid--stimulating hormone measured at 3, 6 and 12 months. Iatrogenic hypothyroidism was confirmed (n=28) or excluded (n=14) on the basis of thyroid scintigraphy. A total of 14 cats with chronic kidney disease and 166 clinically normal cats underwent similar serum thyroid testing and scintigraphy.Concentrations of thyroxine and free thyroxine were lower and thyroid-stimulating hormone higher in hypothyroid cats than in all three groups of euthyroid cats (P0·0001). Of the hypothyroid cats, thyroxine and free thyroxine concentrations were low in 15 (53·6%) and seven (25%), respectively. Low serum thyroxine and free thyroxine concentrations were also detected in seven (50%) and two (14·3%) of the cats with chronic kidney disease. Thyroid-stimulating hormone concentrations were elevated in all hypothyroid cats but remained within the reference interval in all three groups of euthyroid cats. Serum thyroid--stimulating hormone had a higher test sensitivity and specificity than either thyroxine or free thyroxine concentration.The finding of high serum thyroid-stimulating hormone concentrations best identifies feline iatrogenic hypothyroidism and differentiates it from non-thyroidal illness syndrome in cats that develop azotaemia after treatment.

Cooked and peeled cold-water shrimp (Pandalus jordani) naturally contaminated with Listeria monocytogenes were obtained from a processor for a series of studies to determine the level of contamination and growth characteristics of this bacterium in the naturally contaminated product. L. monocytogenes was isolated from every 25-g sample of individually quick frozen (IQF) shrimp that was tested. The level of contamination in each composite sample ranged from 5 to 16 colony forming units (CFU) per 25 g. When individual shrimp taken from the 25-g sample portions were tested separately, samples positive for L. monocytogenes ranged from 1 of 12 to 5 of 15 shrimp tested. The project also evaluated the effectiveness of three methods to inactivate the bacterium: ozone, chlorine dioxide, and steam as possible product reconditioning strategies. Ozone and chlorine dioxide were both found to be ineffective reconditioning treatments for shrimp naturally contaminated with L. monocytogenes. Experiments with stea...

Ready-to-eat picked meat of Dungeness crab (Cancer magister) packaged under vacuum in hermetically sealed (No. 10, five pound) cans, has become a public health concern because the product does not receive a process to inactivate Clostridium botulinum and refrigeration is the only barrier to prevent this bacterium from growing and producing neurotoxins. However, crab meat packaged in this manner has been distributed on ice to retail stores and restaurants for over 50 years without any reported illnesses from C. botulinum. Studies were therefore made to determine conditions that may have contributed to the safety of this product. C. botulinum type E was shown to be present in live Dungeness crab entering the processing facility, but was not detectable after the crabs were cooked in boiling water for ten minutes, nor in picked crab meat. Crab meat samples were inoculated with 10, 100, 1000 and 10,000 type E or type A spores/50 g, packaged in oxygen-permeable or vacuum packaged in oxygen-impermeable ...

Liquid smoke and sodium lactate (NaL) were evaluated as inhibitors to control microbial growth in Alaskan native-style smoked and dried salmon strips. Brined salmon strips were dipped in aqueous solutions of liquid smoke (25%, 50%, 75%, 100%) or NaL (20%, 40%) and then inoculated with 3000 CFU of Staphylococcus aureus/100 g sample prior to drying in a laboratory smoke house without application of smoke, at 30°C for 5 days. S. aureus populations increased to 105/g in non-dipped control samples, 4.5 × 103/g in 20%, and 4.6 × 102/g in 40% NaL samples. Liquid smoke was not effective at a concentration of 25%, but reduced S. aureus levels below detectable limits when used at higher concentrations. When the additives were tested by a processor in Alaska, aerobic populations were less than 30 CFU/g with 30% NaL and 50% liquid smoke and the water activity (aw) of these finished products was below 0.85, a level that would inhibit further microbial growth. Processors should test their products for microbio...

Mixtures of proteolytic and nonproteolytic strains of toxigenic Clostridium botulinum types A, B, and F; nonproteolytic types B, E, and F; Clostridium sporogenes; and nontoxic E-like organisms resembling nonproteolytic C. botulinum were tested against each other for the purpose of selecting a mixture of compatible C. botulinum strains for inoculated pack studies on the basis of their sensitivity to bacteriophages and bacteriocin-like agents. All of the proteolytic strains produced bacteriocin-like agents that were inhibitory to three or more of the other proteolytic types and C. sporogenes. When selected strains of proteolytic types A and B were grown together, type A cultures produced neurotoxin, but type B toxin production was inhibited. Nonproteolytic strains of C. botulinum also produced bacteriocin-like agents against each other. Of these, type E strain EF4 produced bacteriocin-like agents against both proteolytic and nonproteolytic types of C. botulinum and C. sporogenes. EF4, however, was not inhibitory to the nontoxigenic E-like strains. When EF4 was grown with type A strain 62A, it had an inhibitory effect on type A toxin production. Strain 62A inactivated the type E toxin of EF4 after 7 to 21 days at 30 degrees C. On the basis of the production of these bacteriocin-like agents by different strains of C. botulinum and their potential effect on neurotoxin production, it is very important that compatible strains are used in mixtures for inoculated pack studies to determine the safety of a food process or product.

Microbiological and chemical changes were determined during the smoking and drying of salmon strips processed at 29 to 318C for 4 days at a facility in Alaska in 1993. During the process, Staphylococcus aureus populations increased to more than 10 5 CFU/g after 2 to 3 days of processing. Subsequent laboratory studies showed that a pellicle (dried skinlike surface) formed rapidly on the strips when there was rapid air circulation in the smokehouse and that bacteria embedded in or under the pellicle were able to grow even when heavy smoke deposition occurred. Under these conditions, an inoculum of 26 CFU/ g of S. aureus increased to 10 5 CFU/g after 3 days of processing. Elimination of preprocess drying and reduction in air e ow during smoking resulted in smoke deposition before pellicle formation and enabled the product to reach levels of water-phase salt and water activity that inhibit the growth of S. aureus and Listeria monocytogenes. In 1994, these modie cations were then applied during processing at an Alaskan facility, and S. aureus could not be detected in the e nished product. L. monocytogenes was detected in the raw product area, on the processing tables, and on the raw salmon strips, but it was not detected in the e nished product when the smoke was applied before pellicle formation. Smoking and drying are among the oldest methods of food preservation. Even though we have had considerable experience with these processes, food poisoning outbreaks occasionally occur. Improperly processed products and the lack of understanding that some products may become hazardous if they are stored at temperatures that permit the growth of microbial pathogens have caused these food poisoning outbreaks. In Alaska, native smoked and dried salmon products are processed during the summer months when the e sh are returning to the rivers during the spawning season. Since processing is done under ambient temperature and humidity, the processing time can vary from 4 days to 1 or 2 weeks, depending on weather conditions. This long drying time raises concern, because the drying temperatures are ideal for the growth of bacterial pathogens. During processing, there is a race between the product reaching inhibitory levels of water-phase salt (WPS), moisture, and water activity (aw) and the growth of pathogenic and spoilagetype bacteria. If the product is processed at temperatures of 608C or higher, the nonspore-forming bacteria are usually inactivated. In 1993, we worked with an Alaskan native processor along the Yukon River to learn more about the processes used and the microbiological and chemical composition of smoked and dried salmon. The processor had developed a fairly modern processing facility with stainless steel tabletops, a chlorinated water supply, a refrigeration room, and walls and e oors that could be cleaned and sanitized.

Alaska pollock, fillets, washed, strained and dewatered minced fish (mince), and surimi with cryoprotectants, were analyzed for the presence of Clostridium botulinum. Two of the 912 surimi sub-samples tested were contaminated with type E, and type A was shown to be present in two other sub-samples (0.4% incidence). C. botulinum was not present in 72 sub-samples of mince, 7 fish fillets, or 130 whole unevis-cerated pollock. Surimi is distributed in frozen blocks and used in the manufacturing of imitation crab legs, scallops, shrimp and lobster. The products are usually pasteurized after packaging. Since both the non-proteolytic and proteolytic types were found in the surimi, emphasis should be placed on the combination of time and temperature of pasteurization, water-phase salt of the finished product and on storage of the finished product under continuous refrigeration (below 3°C), or as a frozen product.

The potential to use adult Artemia to deliver erythromycin to first-feeding sockeye salmon, Oncorhynchus nerka (Walbaum), was investigated in three trials. In the first trial, first-feeding sockeye were fed live erythromycin enriched adult Artemia or pellets containing equal amounts of erythromycin for 35 days. At the end of the trial, tissue erythromycin concentration of the fish fed the live Artemia was significantly greater (P < 0.05, 25.52 +/- 1.29 microg mL(-1); mean +/- SEM), than the tissue concentration of the fish fed the pellets (0.72 +/- 0.01 microg mL(-1)). In the second trial, first-feeding sockeye were fed either live or freeze-dried bioencapsulated erythromycin (adult Artemia) or pellets containing erythromycin daily for 21 days. Mean daily erythromycin concentration in fish fed the freeze-dried Artemia, live Artemia, or pellets did not differ significantly. In the third trial, apparent erythromycin digestibility was determined. Significantly more (P < 0.05) erythromycin was retained by juvenile sockeye fed freeze-dried bioencapsulated erythromycin (98.3 +/- 1.0%) compared with medicated pellets (89.2 +/- 1.7%). Uptake of bioencapsulated erythromycin from adult Artemia (live or freeze-dried) appears to be greater than uptake from pellets. Freeze-dried and live Artemia were equally effective at delivery suggesting enriched freeze-dried adult Artemia could be produced into a highly palatable, consistent, off-the-shelf product.

Water phase sodium chloride (WPS) levels of 1.8 to 3.0% in combination with heat pasteurization for 15 min at temperatures of 75, 80, 85, and 90 degrees C were evaluated as methods for the inactivation or inhibition of nonproteolytic, psychrotrophic Clostridium botulinum types B and E in crab analogs (imitation crab legs) subsequently stored at 10 and 25 degrees C. Samples inoculated with 10(2) type B or E spores per g prior to pasteurization remained nontoxic for 120 days at 10 degrees C and for 15 days at 25 degrees C. With 10(4) type E spores per g and 80 degrees C pasteurization, > or = 2.4 and 2.7% WPS was required for inhibition at 10 and 25 degrees C storage, respectively. Pasteurization at 85 degrees C decreased the inhibitory level of WPS to 2.1% at 10 degrees C and to 2.4% at 25 degrees C. When the inoculum was 10(4) type B spores per g, samples with 2.7% WPS were toxic after 80 days of storage at 10 degrees C. Samples inoculated with 10(3) type B spores per g and processed at 85 degrees C remained nontoxic for 15 days at 25 degrees C with a WPS of > or = 2.4%. When pasteurization was carried out before inoculation and packaging, 1.8% WPS prevented toxin production by 10(2) and 10(4) type E spores per g for 30 days at 10 degrees C, and this time period increased as the WPS concentrations increased. Three percent WPS prevented toxin production by 10(4) type E spores per g in vacuum-packaged analogs stored 110 days at 10 degrees C. Pasteurization processes used in these experiments, however, do not inactivate the heat-resistant proteolytic types of Clostridium botulinum. Therefore, the most important factor controlling the growth of this bacterium is continuous refrigeration below 3.0 degrees C or frozen storage of the finished product.

Live adult brine shrimp, Artemia franciscana (Latreille), were enriched with erythromycin to determine if Artemia could accumulate therapeutic levels for subsequent feeding to young fish. Three trials were conducted to determine the erythromycin incorporation and survival rates of enriched Artemia when fed either liposomes containing erythromycin or various erythromycin suspensions. Erythromycin concentration in Artemia fed a liposome suspension was low (∼ 5 μg mL−1) relative to Artemia fed the direct suspension (> 100 μg mL−1) over the same time period. When enriched with suspensions up to 1 g erythromycin L−1 sea water for 14 h, Artemia survival was not significantly affected (P > 0.05) relative to controls. Using a suspension of 1 g L−1, tissue erythromycin concentrations of 109 ± 16 μg erythromycin mL−1 Artemia homogenate (mean ± SEM) were achieved after 12 h. Concentrations above 170 μg mL−1 were obtained using suspensions of 2–5 g L−1, but Artemia survival significantly (P

The nonpolymorphic, nonclassical class II molecule DM has been shown to be important in the processing and presentation of antigenic epitopes by MHC class II molecules. The dependence of class II molecules on the coexpression of DM varies with the particular allele or epitope studied. In an effort to resolve disparities that exist for some alleles of class II in their requirements for DM, we have constructed a species-matched murine transfection model with which we can test both the functional and biochemical consequences of DM expression for different alleles of murine class II. When we evaluated the ability of class II molecules to form SDS-stable dimer and release CLIP, we find that while I-A(d) requires DM for the formation of SDS-stable dimers and the release of CLIP, I-A(k) is capable of both SDS-stable dimer formation and CLIP release in the absence of DM. Despite the apparent differences in the biochemical consequences of DM expression for I-A(d) and I-A(k), we find that Ag presentation by both alleles can be enhanced by the expression of DM. Interestingly, we find that DM can facilitate the removal of a natural intermediate in Ii processing (p12). The ability of DM to catalyze the dissociation of p12 and possibly larger Ii fragments from class II in vivo offers a possible mechanism to account for the observed DM enhancement of Ag presentation for alleles that have a low affinity for CLIP. Our findings indicate that DM may function in multiple compartments and on multiple class II/Ii substrates.

Cold-smoked salmon processing plants were surveyed to determine the occurrence and sources of L. monocytogenes contamination. Sanitation and cleanup procedures adequately eliminated L. monocytogenes from the processing line and equipment, but recontamination occurred soon after resumption of processing. The primary source of contamination proved to be the surface areas of frozen or fresh raw fish coming into the plant. Listeria species were not isolated from the flesh except when they were introduced during the filleting operation, by the injection of recirculated brine, or in localized areas where there were pre-existing bruises. Penetration of L. monocytogenes into intact flesh via the vascular system did not occur when fresh fish were immobilized with carbon dioxide and bled, nor when frozen, headed, and eviscerated fish were thawed for 20 h in water inoculated with 44 L. monocytogenes organisms per ml. Populations of L. monocytogenes inoculated onto the surface of brined salmon portions changed very little during a cold-smoke process at 72 to 87°F (22.2 to 30.6°C) for 20 h, with or without applied smoke; but when the processing temperature was lowered to 63 to 70°F (17.2 to 21.1°C), populations decreased 10- to 25-fold when smoke was applied. L. monocytogenes injected into the interior of these portions increased 2- to 6-fold at 63 to 70°F (17.2 to 21.1°C) and 100-fold at 72 to 87°F (22.2 to 30.6°C), regardless of the presence of smoke. L. monocytogenes was enumerated in 48 contaminated finished products collected from six different processing plants. L. monocytogenes populations ranged from 0.3 to 34.3 cells per g, with a mean of 6.2 per g and a median of 3.2 per g.

The behavior of Listeria monocytogenes in relation to sodium nitrite (NaNO2) in combination with sodium chloride (NaCl) was evaluated in cold-process (smoked) salmon during storage at 5 or 10°C in either oxygen-permeable film or vacuum-sealed impermeable film. Salmon slices containing either 3 or 5% water-phase NaCl, with or without 190–200 ppm of NaNO2, were inoculated with 10 or 327 CFU/g (150 or 4.9 × 103 CFU/15-g sample) of strain Scott A. The inhibitory contribution of NaNO2 was relative to inoculum size, storage time and temperature, packaging method, and concentration of NaCl. There was less growth of L. monocytogenes in vacuum-packaged samples as compared to those packaged in oxygen-permeable film. The most inhibition was achieved in vacuum-packaged products stored at 5°C, where NaNO2 in combination with 5% water-phase NaCl prevented any increase in a 10 CFU/g-inoculum during 34 d storage. At 10°C, inhibition was initially enhanced by NaNO2, but by 32 d L. monocytogenes populations had increased f...

The behavior of Listeria monocytogenes (10 Scott A cells per g) in cold-process (smoked) salmon containing 3, 5, or 6% water-phase NaCl was evaluated during 30 to 40 d storage at 5 or 10°C in either oxygen-permeable film or vacuum-sealed impermeable film. At 10°C, L. monocytogenes grew to 106 to 108 CFU/g by the second week, with no differences attributed to NaCl concentration except for an initial lag in the 6% NaCl samples. Vacuum packaging suppressed growth of L. monocytogenes by 10- to 100-fold in samples with 3 or 5% NaCl. Inhibition related to NaCl concentration was most apparent at 5°C and L. monocytogenes populations were held below 102 CFU/g by 6% NaCl. Growth of a 327 CFU/g inoculum was about 10-fold greater than a 10 CFU/g inoculum at 10°C and 100-fold greater at 5°C. Growth of two strains isolated from naturally contaminated, commercially prepared, cold-smoked fish did not differ from Scott A. The use of sugar in the product did not influence growth of L. monocytogenes . Maximum populations of aerobic microorganisms reached at 5 and 10°C were similar, although the rate of growth was somewhat delayed at 5°C, and some inhibition was shown by 5 and 6% NaCl and by vacuum packaging.

Hemolytic ceftazidime lithium chloride agar (HCLA) has been developed as a selective and differential plating medium for the isolation of Listeria monocytogenes from fishery products. Selectivity is based upon lithium chloride, colistin methane sulfonate, and ceftazidime. When horse blood was incorporated in the agar overlay, L. monocytogenes colonies were easily distinguished by their characteristic blue-gray color surrounded by narrow zones of ß-hemolysis. Listeria innocua , a species commonly present in foods, does not produce hemolysis on the medium. Therefore, one or more colonies of L. monocytogenes were easily distinguished from large populations of L. innocua . When used in combination with Food and Drug Administration and U.S. Department of Agriculture enrichment methodology, HCLA was effective in inhibiting competitive organisms, differentiating colonies of L. monocytogenes by their ß-hemolysis, and shortening the incubation time at 35°C for presumptive identification to 17-24 h.

The purpose of this study was to investigate the occurrence of ocular abnormalities in hyperthyroid cats. One hundred hyperthyroid cats and 30 clinically normal, geriatric cats were studied. In both groups, ophthalmic examination was performed by use of slit-lamp biomicroscopy and indirect ophthalmoscopy after application of 1% tropicamide to dilate the pupil. Ocular abnormalities were common in both the hyperthyroid and euthyroid cats. Approximately 75% of all eyes were affected with 1 or more abnormalities, and the range of abnormalities involved all structures of the eye. Significant differences between the euthyroid and hyperthyroid cats were found in the prevalence of prominent suture lines, nonpigmented deposits on the posterior lens capsule, hyperreflective ring around the optic nerve, and hyperpigmentation of the area centralis, but all of these abnormalities were more common in the euthyroid cats than in the cats with hyperthyroidism. Active retinal lesions were only observed in 3 hyperthyroid cats (3%). The results of this study indicate that hyperthyroidism does not seem to be a frequent cause of abnormalities in the eyes of cats.

The pathologic changes associated with hyperthyroidism (adenomatous hyperplasia, adenoma of the thyroid gland) have been well characterized in cats, but the pathogenesis of these changes remains unclear. In this research, we undertook a case-control study to search for potential risk factors for this disease. Owners of 379 hyperthyroid and 351 control cats were questioned about their cats' exposure to potential risk factors including breed, demographic factors, medical history, indoor environment, chemicals applied to the cat and environment, and diet. The association between these hypothesized risk factors and outcome of disease was evaluated by conditional logistic regression. Two genetically related cat breeds (ie, Siamese and Himalayan) were found to have diminished risk of developing hyperthyroidism. Cats that used litter had higher risk of developing hyperthyroidism than those that did not. Use of topical ectoparasite preparations was associated with increased risk of developing hyperthyroidism. Compared with cats that did not eat canned food, those that ate commercially prepared canned food had an approximate 2-fold increase in risk of disease. When these 4 variables (breed, use of cat litter, consumption of canned cat food, and use of topical ectoparasite preparations) from the univariate analysis were selected for further study as candidate risk factors and analyzed by multivariate conditional logistic regression, a persistent protective effect of breed (ie, Siamese or Himalayan) was found. In addition, results suggested a 2- to 3-fold increase in risk of developing hyperthyroidism among cats eating a diet composed mostly of canned cat food and a 3-fold increase in risk among those using cat litter. In contrast, the use of commercial flea products did not retain a strong association. The results of this study indicate that further research into dietary and other potentially important environmental factors (eg, cat litter) is warranted.

To determine whether administration of phenobarbital, potassium bromide, or both drugs concurrently was associated with abnormalities in baseline serum total thyroxine (T4), triiodothyronine (T3), free T4, or thyrotropin (thyroid-stimulating hormone; TSH) concentrations in epileptic dogs.Prospective case series.78 dogs with seizure disorders that did not have any evidence of a thyroid disorder (55 treated with phenobarbital alone, 15 treated with phenobarbital and bromide, and 8 treated with bromide alone) and 150 clinically normal dogs that were not receiving any medication.Serum total T4, total T3, free T4, and TSH concentrations, as well as serum concentrations of anticonvulsant drugs, were measured in the 78 dogs with seizure disorders. Reference ranges for hormone concentrations were established on the basis of results from the 150 clinically normal dogs.Total and free T4 concentrations were significantly lower in dogs receiving phenobarbital (alone or with bromide), compared with concentrations in clinically normal dogs. Administration of bromide alone was not associated with low total or free T4 concentration. Total T3 and TSH concentrations did not differ among groups of dogs.Results indicate that serum total and free T4 concentrations may be low (i.e., in the range typical for dogs with hypothyroidism) in dogs treated with phenobarbital. Serum total T3 and TSH concentrations were not changed significantly in association with phenobarbital administration. Bromide treatment was not associated with any significant change in these serum thyroid hormone concentrations.

To determine whether low doses of synthetic ACTH could induce a maximal cortisol response in clinically normal dogs and to compare a low-dose ACTH stimulation protocol to a standard high-dose ACTH stimulation protocol in dogs with hyperadrenocorticism.Cohort study.6 clinically normal dogs and 7 dogs with hyperadrenocorticism.Each clinically normal dog was given 1 of 3 doses of cosyntropin (1, 5, or 10 micrograms/kg [0.45, 2.3, or 4.5 micrograms/lb] of body weight, i.v.) in random order at 2-week intervals. Samples for determination of plasma cortisol and ACTH concentrations were obtained before and 30, 60, 90, and 120 minutes after ACTH administration. Each dog with hyperadrenocorticism was given 2 doses of cosyntropin (5 micrograms/kg or 250 micrograms/dog) in random order at 2-week intervals. In these dogs, samples for determination of plasma cortisol concentrations were obtained before and 60 minutes after ACTH administration.In the clinically normal dogs, peak cortisol concentration and area under the plasma cortisol response curve did not differ significantly among the 3 doses. However, mean plasma cortisol concentration in dogs given 1 microgram/kg peaked at 60 minutes, whereas dogs given doses of 5 or 10 micrograms/kg had peak cortisol values at 90 minutes. In dogs with hyperadrenocorticism, significant differences were not detected between cortisol concentrations after administration of the low or high dose of cosyntropin.Administration of cosyntropin at a rate of 5 micrograms/kg resulted in maximal stimulation of the adrenal cortex in clinically normal dogs and dogs with hyperadrenocorticism.

Hypoadrenocorticism secondary to bilateral lymphomatous invasion of adrenocortical tissue was diagnosed in 2 adult castrated domestic shorthair cats. In both cats, findings during initial physical examination (ie, lethargy, anorexia, weight loss, and severe weakness) were consistent with severe hypoadrenocorticism. Hyperkalemia, hyponatremia, and azotemia were also detected, which were consistent with hypoadrenocorticism. Hypoadrenocorticism was documented on the basis of finding low baseline and ACTH-stimulated serum cortisol concentrations. The cats initially responded well to treatment, but both owners chose to have the cat euthanatized. Multicentric lymphoma with infiltration and destruction of the adrenal glands was confirmed during necropsy.

To identify factors regulating secretion of alpha-melanocyte-stimulating hormone (alpha-MSH) from the pars intermedia (PI) of the pituitary gland of cats.28 healthy adult cats.Indwelling catheters were placed in 1 jugular vein of each of 7 to 10 cats, depending on treatment group. Sixteen hours later, 3 blood samples were collected for determination of baseline plasma hormone concentrations, and saline solution or a test substance (haloperidol, corticotropin-releasing hormone, bromocriptine, isoproterenol, insulin, or dexamethasone) was administered via the catheter. Subsequent blood samples were collected at regular intervals for up to 240 minutes after injection. Concentrations of ACTH, cortisol, and alpha-MSH were measured in plasma by use of specific radioimmunoassays. Cats were rested for at least 3 weeks between experiments.Administration of haloperidol and isoproterenol resulted in increased, and bromocriptine and insulin in decreased, circulating concentrations of alpha-MSH from baseline. ACTH and plasma cortisol concentrations increased after administration of all test substances except dexamethasone. Dexamethasone injection resulted in decreased plasma concentrations of ACTH and cortisol.Secretion of alpha-MSH from the PI of cats appears to be inhibited by dopaminergic activity and stimulated by beta-adrenergic influences. Activation of secretion of alpha-MSH from the PI can be dissociated from activation of secretion of other pro-opiomelanocortin-derived peptides, such as ACTH, arising from the pars distalis. Regulation of secretory activity of the PI of cats resembles that of rats.

To determine whether measurement of baseline serum concentrations of total thyroxine (T4), and triiodothyronine (T3), free T4, and thyrotropin (thyroid-stimulating hormone; TSH) would aid in the diagnosis of hypothyroidism in dogs.Prospective case series.54 dogs with hypothyroidism, 54 euthyroid dogs with nonthyroidal disease initially suspected to have hypothyroidism, and 150 clinically normal dogs.In the 54 dogs with hypothyroidism, diagnosis was established on the basis of clinical signs, results of routine laboratory and TSH stimulation tests, exclusion of concurrent nonthyroidal disease, and a good clinical response to treatment with L-thyroxine. Blood samples were collected from all dogs and were tested for thyroid hormone and TSH concentrations. Reference ranges for hormone concentrations were established on the basis of results for the 150 clinically normal dogs.Of the 54 hypothyroid dogs, 48 (89%) had low total T4 concentrations, 3 had low-normal concentrations, and 3 had high concentrations because of T4 autoantibodies. In contrast, only 10 (18%) euthyroid dogs had low total T4 concentrations. Only 3 of 31 (10%) hypothyroid dogs had low T3 concentrations; 23 had concentrations within the reference range, and 5 had high concentrations because of T3 autoantibodies. Only 3 of 38 euthyroid dogs had low T3 concentrations. Of the hypothyroid dogs, 53 (98%) had low free T4 concentrations and 1 had a low-normal concentration. Only 4 (7%) euthyroid dogs had low free T4 concentrations. Of the hypothyroid dogs, 41 (76%) had high TSH concentrations, and 13 had TSH concentrations within the reference range. Of the euthyroid dogs, only 4 (8%) had high TSH concentrations. Of all single hormone measurements evaluated, measurement of free T4 concentration had the highest sensitivity (0.98), specificity (0.93), and accuracy (0.95) as a test for hypothyroidism; measurement of total T4 concentration had a lower sensitivity (0.89), specificity (0.82), and accuracy (0.85). Compared with measurement of total or free T4 concentration, measurement of TSH concentration had a lower sensitivity (0.76) and accuracy (0.84) but specificity (0.93) equal to that for measurement of free T4 concentration. When T4 (total or free) and TSH concentrations were evaluated together, specificity was higher than when T4 or TSH concentration was evaluated alone. Only 1 euthyroid dog had low T4 (total and free) and high TSH concentrations.Results indicate that measurement of serum free T4 and TSH concentrations is useful for diagnosis of hypothyroidism in dogs. About a quarter of the dogs with confirmed hypothyroidism, however, will have serum TSH concentrations within reference limits.

To evaluate the efficacy and safety of ipodate in the treatment of hyperthyroidism in cats.Prospective case series.12 cats with hyperthyroidism treated at The Animal Medical Center between November 1994 and March 1996.Each cat initially received 100 mg of ipodate/d, PO. The drug's effects on clinical signs, body weight, heart rate, and serum triiodothyronine (T3) and thyroxine concentrations were evaluated 2, 4, 6, 10, and 14 weeks after initiation of treatment. A CBC and serum biochemical analyses were performed at each evaluation to monitor potential adverse effects of the drug. Dosage of ipodate was increased to 150 mg/d and then to 200 mg/d at 2-week intervals if a good clinical response was not observed.8 cats responded to treatment and 4 did not. Among cats that responded, mean body weight increased and mean heart rate and serum T3 concentration decreased during the study period. Among cats that did not respond, mean body weight decreased and mean heart rate and serum T3 concentration were not significantly changed. Serum thyroxine concentration remained high in all cats. Adverse clinical signs or hematologic abnormalities attributable to ipodate treatment were not reported in any of the cats.Ipodate may be a feasible alternative to methimazole for medical treatment of hyperthyroidism in cats, particularly those that cannot tolerate methimazole and are not candidates for surgery or radiotherapy. Cats with severe hyperthyroidism are less likely to respond to ipodate than are cats with mild or moderate disease, and cats in which serum T3 concentration does not return to the reference range are unlikely to have an adequate improvement in clinical signs.

To evaluate clinical, laboratory, radiographic, ultrasonographic, surgical, and histologic findings in ferrets with insulinoma and to determine their long-term outcome.Retrospective study.57 ferrets with a histopathologic diagnosis of pancreatic islet cell tumor.Medical records of ferrets with pancreatic islet cell tumors were reviewed.Lethargy, weakness, and collapse were the most common clinical signs. All ferrets had hypoglycemia, and hyperinsulinemia was documented in 39 of 47 (83%) ferrets. Ultrasonographic examination of the abdomen revealed pancreatic nodules in 5 of 23 ferrets. Surgical treatment was performed in 50 ferrets, 3 were treated by medical management alone, and 4 did not have treatment. At the time of surgery, 1 pancreatic nodule was found in 13 (26%) ferrets and multiple nodules were found in 37 (74%) ferrets. Pancreatic carcinoma alone was found in 34 ferrets. Whereas a combination of carcinoma and either hyperplasia or adenoma was found in 23 ferrets; 4 ferrets had metastasis to regional lymph nodes or liver. In 26 (53%) ferrets, hypoglycemia persisted after surgery, necessitating medical treatment with prednisone, diazoxide, or both. Sixteen (33%) ferrets had redevelopment of hypoglycemia at 1 to 23.5 months (median, 10.6 months) after surgery. Only 7 of the 50 (14%) ferrets remained euglycemic after surgery.In ferrets, surgical removal of insulin-secreting pancreatic islet cell tumors is recommended as definitive treatment; however, multiple pancreatic nodules are common, making complete excision of all tumor tissue difficult. Persistent hypoglycemia after surgical treatment indicates that lifelong medical management with prednisone or diazoxide or both may be necessary in many ferrets. Finally, because the insulin-secreting tumors are malignant, long-term cure and survival are not likely.

To determine plasma concentrations of steroid hormones in ferrets with hyperadrenocorticism associated with adrenocortical neoplasia or nodular hyperplasia of the adrenal gland, the effect of surgical removal of the affected adrenal gland on concentrations of these hormones, and whether any hormone concentrations could be used as a marker for the disease.Prospective case series.32 ferrets with hyperadrenocorticism associated with adrenocortical neoplasia or nodular hyperplasia of the adrenal gland.A blood sample was obtained from each ferret before adrenalectomy. In 26 of the 32 ferrets, a second blood sample was collected 24 to 48 hours after adrenalectomy. Plasma concentrations of 7 hormones were measured (cortisol, estradiol, testosterone, progesterone, 17-hydroxyprogesterone, androstenedione, and dehydroepiandrosterone sulfate).Median plasma concentrations of 17-hydroxyprogesterone, androstenedione, and dehydroepiandrosterone sulfate were significantly higher in ferrets with adrenal gland disease, compared with concentrations in clinically normal ferrets. After adrenalectomy, median concentrations of estradiol, 17-hydroxyprogesterone, and androstenedione decreased significantly. Of 23 ferrets in which concentrations of estradiol, 17-hydroxyprogesterone, and androstenedione all were measured, 22 (96%) had high concentrations of at least 1 of these 3 hormones, but only 5 (22%) ferrets had high concentrations of all 3 hormones.The condition that develops in ferrets with adrenal gland disease apparently is caused by excessive secretion of 1 or more steroids other than cortisol. Because concentration of a particular hormone was not high in all ferrets, we recommend determining plasma concentrations of several sex steroids, including androstenedione, 17-hydroxyprogesterone, and estradiol.

To assess pretreatment clinical and laboratory findings in cats with diabetes mellitus and to determine the influence of ketoacidosis on pretreatment findings.Retrospective case series.104 cats with diabetes mellitus, 38 of which had ketoacidosis.Medical records of cats with diabetes mellitus examined over a 20-month period were reviewed. Cats that had received previous treatment for diabetes mellitus, or for which medical records were incomplete, were excluded from this study.Cats ranged in age from 1 to 19 years (median, 11 years). Male cats were twice as likely to develop diabetes as females. The most common historical signs were polyuria, polydipsia, weight loss, and diminished activity. Anorexia or poor appetite was reported more commonly than polyphagia, especially in cats with ketoacidosis. Diminished activity, anorexia, weakness, and vomiting were all significantly more common in ketoacidotic cats than in nonketoacidotic cats. Forty-four cats were considered thin, and 34 were considered obese. All cats had hyperglycemia and most had hypercholesterolemia and high activities of 1 or more hepatic enzymes. Compared with nonketoacidotic cats, ketoacidotic cats were more likely to have had low serum electrolyte values. All cats had glucosuria and 42 (40.4%) had ketonuria. Baseline serum insulin concentrations were measured in 18 cats and were low or at the low end of the reference range in 14 (77.8%) cats. Serum fructosamine concentration, determined in 22 cats, was high in 20 (90.9%) cats. Twenty-three of the 104 (22.1%) cats had concurrent disease, the most common of which were hyperthyroidism, inflammatory bowel disease, and eosinophilic granuloma complex.In more than a third of cats, diabetes mellitus is complicated by development of ketoacidosis, which increases the severity of clinical and laboratory abnormalities. Diagnosis of diabetes mellitus is made on the basis of signalment (e.g., middle-aged to old male cats), owner complaints (e.g., polyuria, polydipsia, and weight loss), physical examination findings (e.g., lethargy or muscle wasting), and laboratory findings (e.g., hyperglycemia and glucosuria).

To evaluate clinical and laboratory findings in 225 dogs with naturally occurring hypoadrenocorticism diagnosed over a 14-year period.Retrospective case series.220 dogs with primary hypoadrenocorticism and 5 dogs with secondary hypoadrenocorticism (primary ACTH deficiency).We reviewed medical records of all dogs with naturally occurring hypoadrenocorticism examined at The Animal Medical Center between 1979 and 1993 or at Tufts University, Foster Hospital for Small Animals, between 1987 and 1993.Dogs ranged from 4 months to 14 years old. Most (71%) were female, and female dogs had a significantly higher relative risk of developing hypoadrenocorticism than did males. Great Danes, Portuguese Water Dogs, Rottweilers, Standard Poodles, West Highland White Terriers, and Wheaton Terriers had a significantly higher relative risk of developing hypoadrenocorticism than did dogs of other breeds. Common owner complaints included lethargy, poor appetite, and vomiting, whereas lethargy, weakness, and dehydration were common abnormalities detected on physical examination. Serum biochemical testing at the time of diagnosis revealed moderate-to-severe azotemia and hyperphosphatemia in most dogs. In 99 of 172 (57.6%) dogs that had a pretreatment urinalysis performed, urine specific gravity was1.030 even though dogs were azotemic. Serum electrolyte changes included hyperkalemia (n = 215), hyponatremia (183), hypochloremia (94), and hypercalcemia (69). Five of the 220 dogs with primary hypoadrenocorticism and the 5 dogs with secondary hypoadrenocorticism did not have hyperkalemia at time of diagnosis. In all dogs, ACTH stimulation testing revealed a low to low-normal baseline serum cortisol concentration with little to no rise after ACTH administration. Endogenous plasma ACTH concentration measured in 35 dogs with primary hypoadrenocorticism was markedly high; whereas ACTH concentration was undetectable to low in the 5 dogs with secondary hypoadrenocorticism.hypoadrenocorticism is a rare disease in dogs, most commonly affecting young to middle-aged females; some breeds are at greater risk of developing the disease than others. In general, clinical signs are nonspecific and similar to manifestations of more common diseases. Serum electrolyte disturbances of hyperkalemia and hypernatremia are characteristic in dogs with primary hypoadrenocorticism, but concentrations may be normal in dogs with early or mild primary or secondary hypoadrenocorticism. Diagnosis of hypoadrenocorticism is best confirmed by demonstration of a low baseline serum cortisol concentration with a subnormal or negligible response to ACTH administration. Determination of endogenous plasma ACTH concentrations is valuable in differentiating primary from secondary hypoadrenocorticism, particularly in dogs with normal serum electrolyte concentrations.

To evaluate a protocol for subcutaneous radioiodine treatment of cats with hyperthyroidism in which the dose was determined on the basis of severity of the cat's clinical signs, thyroid tumor size, and magnitude of the serum thyroxine (T4) concentration.Prospective case series.524 cats with hyperthyroidism.A scoring system based on 3 factors (severity of clinical signs, size of the thyroid gland, and magnitude of the serum T4 concentration) was used to select the dose of radioiodine to be administered subcutaneously.On the basis of the scoring system, 310 (59%) cats were treated with a low dose of radioiodine (3.5 mCi; median, 3.0 mCi), 158 (30%) were treated with a moderate dose (3.5 to 4.4 mCi; median, 4.0 mCi), and 56 (11%) were treated with a high dose (or = 4.5 mCi; median, 5.0 mCi). At time of discharge from the hospital, serum T4 concentration was still high in 80 (15.3%) cats, but by 6 months after administration of radioiodine, the serum T4 concentration had decreased to within or below reference range in all but 8 (1.5%) cats with persistent hyperthyroidism. Many cats had low serum T4 concentrations at some time after radioiodine treatment, but only 11 (2.1%) cats developed clinical and clinicopathologic features of hypothyroidism and required supplementation with L-thyroxine. Thirteen (2.5%) cats had a relapse of hyperthyroidism 1.1 to 6.5 years after initial radioiodine treatment. Overall, the response to treatment was considered good in 94.2% of the cats. Median survival time in the cats was 2.0 years; the percentage of cats alive after 1, 2, and 3 years of treatment was 89, 72, and 52%, respectively.Results of the study suggest that this method of dose estimation works well and that subcutaneous administration of radioiodine provides a safe and effective means of treating hyperthyroidism in cats.

The purpose of the study reported here was to assess 3 commonly used screening tests for hyperadrenocorticism (low-dose dexamethasone suppression test, ACTH stimulation test, and urinary cortisol:creatinine ratio) in dogs with various diseases other than those of the adrenal glands (nonadrenal diseases). A group of 100 dogs was studied: 59 dogs with nonadrenal disease, 21 clinically normal dogs, and 20 dogs with pituitary-dependent hyperadrenocorticism. Of 59 dogs with nonadrenal disease, 20 (34%) had high baseline cortisol concentration (greater than reference range limits), and 22 (38%) and 33 (56%) had inadequate serum cortisol suppression at 4 and 8 hours, respectively, after administration of a low dose of dexamethasone. Compared with clinically normal dogs, dogs with nonadrenal disease had significantly (P0.05) higher mean serum cortisol concentration at 4 and 8 hours after administration of a low dose of dexamethasone; however, significant differences were not detected between the mean cortisol concentration at 8 hours after administration for dogs with nonadrenal disease and for dogs with hyperadrenocorticism. After ACTH stimulation, only 8 of 59 (14%) dogs with nonadrenal disease had high serum cortisol concentrations. Significant differences did not exist after ACTH stimulation between mean cortisol concentration of clinically normal dogs and that of dogs with nonadrenal disease. Of 59 dogs with nonadrenal disease, 45 (76%) had a high urinary cortisol:creatinine ratio. When compared with clinically normal dogs, dogs with nonadrenal disease had a significantly higher mean urinary cortisol:creatinine ratio, but significant differences did not exist between the mean urinary cortisol:creatinine ratio of dogs with nonadrenal disease and that of dogs with hyperadrenocorticism.(ABSTRACT TRUNCATED AT 250 WORDS)

A study was designed to evaluate the effects of desoxycorticosterone pivalate (DOCP) on blood pressure in 8 dogs with primary hypoadrenocorticism, and to attempt to identify other factors that might suggest overdosage of the drug. In 4 dogs, primary hypoadrenocorticism had been diagnosed immediately before entry of the dog into the study, and the dogs had not received any mineralocorticoid supplementation. In the other 4 dogs, primary hypoadrenocorticism had been diagnosed 1 to 6 years previously, and dogs were being treated with DOCP at the time of entry into the study. In all 8 dogs, DOCP (2.2 mg/kg of body weight, IM) was administered on days 0, 30, 60, and 90 of the study; each dog was examined on days 0, 30, 60, 75, 90, and 105. At the time of each visit, a medical history was obtained, a complete physical examination and serum biochemical analyses were performed, and body weight and blood pressure were measured. Doppler-shift ultrasonic sphygmomanometry was used to indirectly record systemic systolic and diastolic pressures. None of the dogs developed hypernatremia or hypokalemia or any clinical signs suggestive of hypoadrenocorticism during the study. However, in 6 dogs (3 that had not been previously treated with mineralocorticoids and 3 that had been), there was a significant increase in body weight over the course of the study. Compared with baseline (day 0) arterial blood pressure, neither systolic nor diastolic blood pressure was significantly increased during the study, and all systolic and diastolic blood pressure measurements were within reference ranges at all evaluation times.(ABSTRACT TRUNCATED AT 250 WORDS)

Thirty-two dogs with hyperadrenocorticism caused by cortisol-secreting adrenocortical neoplasia were treated with mitotane at an initial daily induction dosage of 27.5 to 75.0 mg/kg of body weight (mean, 46.3 mg/kg) for 10 to 14 days. All dogs received daily maintenance glucocorticoid supplementation during the induction period. After 2 weeks, the ACTH-stimulated serum cortisol concentration had decreased to within or below the reference range for baseline cortisol concentration in 18 (56.3%) of the 32 dogs; the remaining 14 (43.7%) still responded to ACTH administration with serum cortisol concentrations above the reference range. In these 14 dogs, mitotane was continued at a higher daily dosage (mean, 60.7 mg/kg) for an additional 1 to 9 weeks. Serum cortisol concentration subsequently fell within or below the reference range for baseline cortisol concentration in all but 1 dog. In 30 of the 32 dogs, mitotane was continued at an initial mean maintenance dosage of 101.6 mg/kg/wk, divided into 2 to 5 doses. Twenty-two dogs received prednisone daily (0.2 mg/kg) throughout the maintenance period. One or more relapses occurred in 19 (63%) of the 30 dogs. In dogs with relapse, the mean maintenance mitotane dosage was increased from 98.1 mg/kg/wk to a high of 212.4 mg/kg/wk. After a mean maintenance treatment time of 13.2 months, final mean maintenance dosage required in the 30 dogs ranged from 35.3 to 1,273 mg/kg/wk. Adverse effects were seen in 19 (59.4%) of the 32 dogs as a result of a drug toxicosis associated with high-dosage administration of mitotane, low serum cortisol concentration, or both.(ABSTRACT TRUNCATED AT 250 WORDS)

Nuclear medicine may have both diagnostic and therapeutic utility during the evaluation and management of thyroid disease. This article will focus on the use of radionuclide scintigraphy and radioactive iodine therapy in the diagnosis and treatment of thyroid disease in the dog and cat.

We measured immunoreactive (IR) plasma concentrations of the proopiomelanocortin (POMC)-derived peptides (adrenocorticotropic hormone [ACTH]; beta-endorphin/beta-lipotropin [beta END/beta LPH]; and alpha-melanocyte stimulating hormone [alpha MSH]) and of cortisol in 100 clinically normal cats. Median plasma concentration of IR-ACTH was 2.7 pmol/L (range,or = 1.1 to 22 pmol/L), of beta END/beta LPH was 28 pmol/L (range, 3.8 to 130 pmol/L), of alpha MSH was 36 pmol/L (range,or = 3.6 to 200 pmol/L), and of cortisol was 35 nmol/L (range, 5 to 140 nmol/L). Plasma concentrations of IR-ACTH, alpha MSH, and beta END/beta LPH were at or below the assay sensitivity in 34, 3, and 0% of the cats, respectively. We did not detect a correlation between plasma concentrations of IR-ACTH and beta END/beta LPH (r = 0.23) or between plasma concentrations of IR-ACTH and alpha MSH (r = 0.19). However, there was a significant (P0.001) correlation between plasma concentrations of IR-beta END/beta LPH and alpha MSH (r = 0.81). There was not a significant correlation between plasma concentration of cortisol and plasma concentration of any of the IR-POMC peptides. High plasma concentrations of IR-alpha MSH and beta END, POMC peptides secreted predominantly by melanotrophs in other species, indicate that clinically normal cats have an actively secreting pars intermedia.(ABSTRACT TRUNCATED AT 250 WORDS)