Prediction of the amount and rate of histamine degradation by diamine oxidase (DAO).

Histamine is a biogenic amine that forms in a variety of foods and can cause food poisoning at high concentrations (>500 ppm). In situations where the formation of histamine in food cannot be prevented through refrigeration, diamine oxidase (DAO) enzyme may be used to degrade histamine to safe levels. The aims of this work were to apply DAO in model (buffer) and real (cooked tuna soup used in the manufacture of a fish paste product, Rihaakuru) systems, in order to obtain predictions for the rates and amounts of histamine degradation. The two systems were set up with a constant concentration of histamine (500 mg/L) and the DAO enzyme (2534 units/L) at a temperature of 37°C, agitation at 100 rpm and an incubation time of 10h with variable pH (5-7) and salt concentrations (1-5%). A total of 15 experiments were designed for each system using central composite design (CCD). The data from these experiments were fitted into regression models; initially the data were used to generate an exponential decline model and then the data from this were fitted into a secondary response surface model (RSM) to predict the rate and amount of histamine degradation by DAO. The model system results indicated that DAO activity was not significantly affected by salt (p>0.05), and that activity reached a maximum within the pH range of 6-6.5 with an optimum at pH 6.3. However, the results obtained with the tuna soup model showed that the optimum oxidation of histamine using DAO occurred between pH 6-7 and salt 1-3%. This study defined the conditions for the use of DAO to degrade 500 mg/L of histamine in tuna soup used to manufacture Rihaakuru. The models generated could also be used to predict the rate and amount of histamine degradation in other foods that have similar characteristics to tuna soup.

Pea proteins based food products as meat replacers: the Profetas concept.

Profetas (Protein Foods, Environment, Technology and Society) is a Dutch trans-disciplinary research programme, aiming to develop more sustainable food systems. The central theme of the programme is the question: is a transition feasible from a diet based primarily on animal proteins to a diet based for a large part on new food products made from plant proteins? In the programme this question is studied from very different disciplinary perspectives. In the programme a consumer and chain oriented approach is adopted. In the experimental part of the programme, pea proteins are studied. Profetas is funded by the Netherlands Organisation for Scientific Research, with support from the Ministry of Agriculture, Nature management and Fisheries and the food industry. The programme compromises 16 PhD and post-doctoral projects.

Weakness, tremors, and depression associated with macadamia nuts in dogs.

The ASPCA National Animal Poison Center managed 29 cases of ingestion of commercially available macadamia nuts in dogs during a 5-y period. Clinical signs included, from most to least, weakness, depression, vomiting, ataxia, tremor, hyperthermia, abdominal pain, lameness, stiffness, recumbency, and pale mucous membranes. The onset of clinical signs was reported as < 12 h in 79% of the cases. The duration of clinical signs for the majority of cases was < 24 h. The amount of macadamia nuts ingested was estimated in 72% of the calls with a mean of 11.7 g/kg bw. In an attempt to reproduce the syndrome, 4 dogs were gavaged with 20 g macadamia nuts/kg bw in a water slurry. The experimentally dosed dogs developed weakness, manifested by the inability to rise 12 h after dosing, mild central nervous system depression, vomiting, and hyperthermia, with rectal temperatures up to 40.5 C. Mild elevations in serum triglycerides and serum alkaline phosphatase were detected. Lipase values peaked sharply at 24 h and returned to normal by 48 h after dosing. Other serum biochemical and electrolyte determinations were unremarkable. Serum lipoprotein electrophoresis determinations were unchanged from baseline. The mechanism of the syndrome is unknown. All field and experimental dogs recovered uneventfully within 1 to 2 d whether treated by a veterinarian or not.

Effect of Blanching on Structural Quality of Dried Potato Slices.

Mechanical properties of potato slices were monitored during blanching, as indicators of structural changes. As expected, blanching resulted in weakening of potato structure. Gelatinization, which occurred during the first 2 min, did not promote an immediate weakening of the potato tissue. More than 80% of the changes in mechanical properties occurred during the first 30 min of blanching. Potato slices blanched for 2 and 30 min as well as unblanched ones were dried in a convective air drier at 48 degrees C. Bulk and true density, porosity, and shrinkage were monitored with time. Blanched potatoes resulted in a significantly more compact, less porous product with lower effective water diffusivity than unblanched potatoes. The results indicated that changes that occurred during the first 2 min of blanching had a much greater influence on structural quality of dried potatoes than changes that occurred from 2 to 30 min of blanching.

Absence of detectable fumonisins in the milk of cows fed Fusarium proliferatum (Matsushima) Nirenberg culture material.

Fumonisins, a group of mycotoxins produced by the ubiquitous fungi Fusarium moniliforme and F. proliferatum, were first identified about eight years ago. They have been shown to cause a variety of health effects in animals, including epidemiological evidence of esophageal cancer in humans. Cattle are less sensitive to ill effects than horses and swine. Fumonisins are common contaminants of low quality grain fed to cattle. Culture material containing fumonisins (FB1, FB2, and FB3) was mixed into the total diet and fed for 14 days to two midlactation Jersey cows to determine if fumonisins are excreted in milk. The dietary equivalent of fumonisin was approximately 75 ppm and the two cows consumed an average of 3 mg fumonisin B1/kg body weight (bwt)/day. Fumonisins were not detected in any of the milk samples by two analytical laboratories using methods with a sensitivity of 5 ng/ml. Except for transient diarrhea at the beginning of the contaminant feeding period and an increase in serum cholesterol, clinical and hematologic changes were not observed in the animals. The appearance or carry over of fumonisins from feed to milk in dairy cows does not appear to be significant and likely not a hazard or food safety concern for humans.

Aldicarb toxicosis in a flock of sheep.

Aldicarb toxicosis was diagnosed in 200 sheep that died suddenly. Carbamate insecticide toxicosis was suspected based on observed clinical signs (hypersalivation, diarrhea, urination, paddling, seizures, miosis, and deaths occurring within 1 hour). Tissue samples were submitted from 4 Columbian ewes for pathologic and analytical evaluation. Severe diffuse pulmonary edema was observed on gross and histologic examination. Inhibition of cholinesterase activity in retina (21.2-68.1% of normal activity, n = 3), brain (40.6-45.6% of normal activity, n = 3), and whole blood (27% of normal activity, n = 1) supported a diagnosis of carbamate toxicosis. Reversal of brain and whole blood cholinesterase activities (reactivation factor greater than 1.4) following an in vitro 1 hour incubation at 37 C was also consistent with carbamate poisoning. Aldicarb toxicosis was confirmed following its detection in rumen contents at 1.5, 5.5, and 334 ppm using both high-pressure liquid chromatography with UV detection and gas chromatography with nitrogen/phosphorus detection.

Toxic effects of trace element excess.

Excesses of many trace elements can cause direct toxic effects to cattle as well as indirect effects that can cause a secondary deficiency of other trace elements. Clinical signs may vary from poor growth and feed utilization to neurologic disorders. Toxic effects vary with the specific trace element in question, the total amount of that element in the diet, the age and condition of the animal, and the presence or absence of certain other dietary components. A diagnosis of toxic trace element interaction is based upon compatible clinical signs in affected animals as well as supporting chemical analyses.

Clinical infections and nonsurgical treatment of parapharyngeal space infections complicating throat infection.

The clinical features and management of eight patients with parapharyngeal space infection who presented with swelling of the neck subsequent to sore throat are described. In four patients the interval between the initial throat symptoms and swelling was 2 days or less, and the disease was rapidly progressive with stridor or a descending mediastinitis. In the other four cases, this interval was longer (4 to 14 days) and the infection was fairly localized. Computed tomography was useful for making the diagnosis, establishing that the infection had spread into other deep neck spaces and the mediastinum, distinguishing abscesses from diffuse cellulitis, guiding drainage aspiration, and assessing the response to therapy. None of the patients underwent extensive surgical drainage of the deep neck spaces. A nonsurgical approach with antibiotics, including high doses of benzylpenicillin, and computed tomography-guided selective needle aspirations proved successful. Even patients with distinct abscesses were completely cured.

Diagnostic features of chlamydia infection in dairy calves.

Chlamydia were routinely isolated from a group of calves with pneumonia, systemic disease, and enteric involvement. The most commonly observed lesions were acute interstitial pneumonia, hepatitis, and enteritis. Cultures of sequentially collected nasal and rectal samples from clinically normal calves revealed a large percentage of inapparent infections during, at least, the first 30 days of age.

Organophosphorus and carbamate insecticide poisoning in large animals.

Organophosphorus and carbamate insecticides are used commonly in agriculture to control pests of crops and animals. These compounds are toxic and livestock poisoning has occurred from mistaken addition of unused insecticide to feeds and animal access to improperly disposed of materials or "empty" containers. The morbidity rate approximates a third of animals exposed and about half of those affected die. Organophosphorus and carbamate insecticides generate their toxic effects by bonding to and inhibiting ChE enzymes (most importantly, AChE), which are responsible for breaking down the neurotransmitter ACh. The accumulation of ACh results in uninhibited impulse transmission at the cholinergic endings, including autonomic preganglionic junctions, certain neurons in the central nervous system, and motor nerves to the skeletal muscles. This eventually leads to fatigue of end organs; death usually is a result of respiratory failure. The "delayed neuropathy syndrome" is caused by some OP insecticides, but the pathophysiology of this syndrome does not involve the inhibition of ChE and accumulation of neurotransmitter. Over 100 anticholinesterase insecticides are in use. Variations in toxicity exist among these compounds, but larger diversities exist in the likelihood of poisoning because of differences in formulations, solvents, and conditions of use. Young animals usually are more sensitive than adults. Some of these agents are among the most toxic of manmade chemicals. These insecticides generally do not accumulate in tissues. The "chronic" effects depend on accrued physiological changes from frequent exposure to nonlethal doses. Clinical signs occur within minutes to a few hours and include the muscarinic signs of salivation, excessive lacrimation, frequent urination, and diarrhea. Concurrent nicotinic effects include muscular tremors followed by weakness and paralysis. Topical exposure results in similar poisoning but the onset of clinical signs may be delayed. Certain pour-on insecticides may cause a delayed (more than a week) syndrome in some breeds. Diagnosis of OP or carbamate insecticide poisoning is made by (1) interpretation of clinical signs and history that are consistent with this poisoning, (2) detection of the chemical compound in stomach or rumen contents and tissues, and (3) demonstration of the adverse biological effect, ChE inhibition.(ABSTRACT TRUNCATED AT 400 WORDS)

Suppurative thrombophlebitis of the superior vena cava.

A 22-year-old woman, a neurosurgical comatose patient developed suppurative thrombophlebitis of the superior vena cava due to Klebsiella pneumoniae, as a complication of catheterisation for parenteral nutrition. The diagnosis was established by gallium scan, computed tomography and digital vascular imaging. Conservative treatment with antibiotics and heparin resulted in the emergence of a resistant mutant of the causative agent. The infection could only be eradicated after surgical thrombectomy.

Emergence of bacterial resistance to cefamandole in vivo due to outer membrane protein deficiency.

Cefamandole therapy in a patient with suppurative thrombophlebitis failed due to selection of a resistant variant of the causative organism Klebsiella pneumoniae. Analysis of the resistance mechanism revealed that in the resistant variant one of the major outer membrane proteins, OmpF, was missing. Resistance of this type has implications for therapy with other antibiotics including non-beta-lactam antibiotics. This report demonstrates the role of outer membrane permeation in the emergence of bacterial resistance during antibiotic therapy.

The induction of equine laminitis with an aqueous extract of the heartwood of black walnut (Juglans nigra).

An aqueous extract of the heartwood of black walnut (Juglans nigra) was given via stomach tube to 10 horses. Eight developed Obel grade 3 or 4 laminitis within 12 hr. Limb edema and mild sedation were the only other clinical signs observed. One horse was euthanized due to severe signs. The other 7 recovered within 6 days. Gas chromatography/mass spectrometry of aqueous extracts of heartwood, bark and nuts of black walnut identified juglone in the bark and nuts, but not in the heartwood. It was concluded that the aqueous extract of heartwood is laminogenic to horses, but the active ingredient is not juglone.

Altered serum element concentrations due to laboratory usage of Vacutainer tubes.

Aliquots of a pooled serum sample (bovine) were agitated in Vacutainer tubes (serum or clot tubes) for 0, 2, 8 and 32 hr to determine if Vacutainer tubes had any effect on serum trace element concentrations. The sera were analyzed for Ca, Cu, Fe, Mg, Na and Zn by the inductively coupled argon plasma emission spectrometer. The Zn concentration in sera was significantly increased over time, and the Cu and Fe concentrations were significantly decreased. Most of these artifacts became apparent within the first 2 hrs of exposure to the Vacutainer tubes. Changes in Cu, Mg and Na concentrations were not detected.

Herd health status of animals exposed to polybrominated biphenyls (PBB).

The health status of 16 herds of dairly cattle exposed to low levels of polybrominated bipenyl (PBB) was compared with that of 15 control herds. Milk production of the contaminated herds was not significantly changed in 1972, 1973, and 1974 and was not significantly different from that of control herds in the same years. Mortality of adult cows and calves, the percentages of cows culled from the herds because of old age and low production, disease, or sterility, and the general health conditions were similar in the two groups. Serum concentrations of calcium, glucose, and cholesterol in contaminated herds were significantly different from those of the control herds, but the relationship to PBB exposure needs further investigation.