Measuring antioxidant effectiveness in food

Many new in vitro methods have been developed to evaluate antioxidant activity. Unfortunately, these in vitro methods often correlate poorly with the ability of compounds to inhibit oxidative deterioration of foods because the in vitro assays do not account for factors such as the physical location of the antioxidant, its interaction with other food components, and environmental conditions. To accurately evaluate the potential of antioxidants in foods, models must be developed that have the chemical, physical, and environmental conditions expected in food products. This paper outlines model systems of the evaluation of antioxidants in three types of foods: bulk oil, oil-in-water emulsions, and muscle foods. These model systems are not intended to be inclusive of all possible methods to measure lipid oxidation and antioxidant activity. However, use of these models would allow researchers to more easily compare research results from one paper to another.     

Australian surveillance for avian influenza viruses in wild birds between July 2005 and June 2007

Objective   To identify and gain an understanding of the influenza viruses circulating in wild birds in Australia.
Design   A total of 16,303 swabs and 3782 blood samples were collected and analysed for avian influenza (AI) viruses from 16,420 wild birds in Australia between July 2005 and June 2007. Anseriformes and Charadriiformes were primarily targeted.
Procedures   Cloacal, oropharyngeal and faecal (environmental) swabs were tested using polymerase chain reaction (PCR) for the AI type A matrix gene. Positive samples underwent virus culture and subtyping. Serum samples were analysed using a blocking enzyme-linked immunosorbent assay for influenza A virus nucleoprotein.
Results   No highly pathogenic AI viruses were identified. However, 164 PCR tests were positive for the AI type A matrix gene, 46 of which were identified to subtype. A total of five viruses were isolated, three of which had a corresponding positive PCR and subtype identification (H3N8, H4N6, H7N6). Low pathogenic AI H5 and/or H7 was present in wild birds in New South Wales, Tasmania, Victoria and Western Australia. Antibodies to influenza A were also detected in 15.0% of the birds sampled.
Conclusions   Although low pathogenic AI virus subtypes are currently circulating in Australia, their prevalence is low (1.0% positive PCR). Surveillance activities for AI in wild birds should be continued to provide further epidemiological information about circulating viruses and to identify any changes in subtype prevalence.     

Predicting and managing channel change in Southeast Australia

The recognition of alternating flood- (FDRs) and drought-dominated regimes (DDRs) in coastal rivers of New South Wales has helped to explain some of the changes in channels and floodplains observed in more recent times. Complex responses, as adjustments to regime shifts and to human-induced catchment and channel changes, can to some extent be forecasted using conceptual models. These in turn can be used to forecast channel and floodplain changes in both high and low energy environments for two future scenarios; one involving a change from the present FDR to a new DDR, and the other, much more complex, a superimposition of greenhouse conditions on firstly a DDR and then on a FDR. The latter situation will see a very unstable landscape and will require management strategies far more sophisticated than those used at present.     

Vacuolar hepatopathy in dogs: 336 cases (1993-2005)

OBJECTIVE: To determine disorders associated with vacuolar hepatopathy (VH), morphologic hepatic and clinicopathologic abnormalities, and affiliation with steroidogenic hormone excess in dogs. DESIGN: Retrospective case series. Animals-336 dogs with histologically confirmed moderate or severe VH. PROCEDURES: Information on signalment, results of diagnostic testing, definitive diagnoses, and exposure to glucocorticoids (ie, exogenous glucocorticoid administration or high endogenous concentrations of steroidogenic hormones) was obtained from medical records. Dogs were grouped by underlying disorder, glucocorticoid exposure, acinar zonal distribution of lesions, and histologic severity. RESULTS: 12 disease groups (neoplastic, acquired hepatobiliary, neurologic, immune-mediated, gastrointestinal tract, renal, infectious, cardiac disease, diabetes mellitus, portosystemic vascular anomaly, adrenal gland dysfunction, and miscellaneous disorders) were identified. There were 186 (55%) dogs with and 150 (45%) dogs without evidence of glucocorticoid exposure. Acinar zonal distribution of hepatic vacuolation and clinicopathologic values did not differ between dogs with and without evidence of glucocorticoid exposure. However, a 3-fold increased likelihood of severe VH was associated with steroidogenic hormone exposure. Of 226 dogs with high serum alkaline phosphatase activity, 102 (45%) had no evidence of glucocorticoid exposure. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that neoplasia and congenital or acquired hepatobiliary disease are common in dogs with VH and provide support for the suggestion that VH, high alkaline phosphatase activity, and illness-invoked physiologic stress may be associated. Histologic confirmation of VH should initiate a diagnostic search for a primary disease if glucocorticoid treatment and hyperadrenocorticism are ruled out.     

Distribution of Brucella abortus organisms in calves after conjunctival exposure

Thirty calves (3 to 4 months old) were exposed conjunctivally to a pathogenic strain of Brucella abortus. Calves were euthanatized and necropsied at postexposure hours 2 and 4, and at postexposure days (PED) 1, 4, 7, 14, 21, 42, and 49. Selected ocular, pharyngeal, and lymphoid tissues were cultured bacteriologically for brucellae to determine organism distribution. Brucella abortus organisms initially localized in the third eyelids, bulbar conjunctivae, and parotid lymph nodes and were detected in these structures until PED 42, 21, and 49 respectively. In calves euthanatized at PED 7, organisms were in other cranial lymph nodes (mandibular and retropharyngeal), and in calves euthanatized at PED 21, organisms were isolated from peripheral lymphoid tissues. Brucellae were not isolated from mesenteric and bronchial lymph nodes and from the spleen until PED 21. The pattern of isolation indicated that conjunctival exposure probably resulted in entrance of brucellae into the host via ocular tissues.