Comparison of methodology for determination of ethylene dibromide in grains and grain-based foods

Three commonly used methods for determination of ethylene dibromide (EDB) in grains and grain products have been compared. EDB residues were extracted by soaking in hexane, triple co-distillation with hexane from an aqueous sample solution, and soaking in acetone-water (5 + 1). Each method was used for triplicate analyses of 12 samples containing incurred residues of EDB ranging from about 10 to 1000 ppb and representing whole grains (wheat and oats) and intermediate grain-based products such as corn meal and flour. The 4-day hexane soaking method extracted the least EDB. In some cases, this was half of the amount determined by the other methods. Levels from soaking in acetone-water were equal to, or up to 25% greater than, those from distillation. Although soaking for 2 days is required for whole grains in the method, a period of only 16 h was found acceptable for ground products. Results were obtained faster with the distillation method, but more analyst time per sample was required. A single distillation recovered about 80% (40-60% from wheat) of total EDB extracted by triple distillation. Foaming was reduced by the addition of concentrated H2SO4 to the aqueous hexane-sample mixture, plus stirring during distillation, thereby allowing complete recovery of the hexane.     

Pseudomonas aeruginosa: growth in distilled water from hospitals

Pseudomonas aeruginosa can grow relatively fast in distilled water obtained in hospitals and achieve high cell contaminations which remain stable for long periods of time. Cells grown in distilled water react quite differently to chemical and physical stresses than cells grown in standard laboratory culture media.     

Effect of neuropeptides on production of inflammatory cytokines by human monocytes

Two groups of mediators, the neuropeptides substance P and K and the monocyte-derived cytokines, interact in the neural regulation of immunological and inflammatory responses. Substance P, substance K, and the carboxyl-terminal peptide SP(4-11) induce the release of interleukin-1, tumor necrosis factor-alpha, and interleukin-6 from human blood monocytes. The neuropeptide effects occur at low doses, are specific as shown by inhibition studies with a substance P antagonist, and require de novo protein synthesis. Since monocyte-derived cytokines regulate multiple cellular functions in inflammation and immunity and since neuropeptides can be released from peripheral nerve endings into surrounding tissues, these findings identify a potent mechanism for nervous system regulation of host defense responses.     

Three-dimensional structure of recombinant human interferon-gamma

The x-ray crystal structure of recombinant human interferon-gamma has been determined with the use of multiple-isomorphous-replacement techniques. Interferon-gamma, which is dimeric in solution, crystallizes with two dimers related by a noncrystallographic twofold axis in the asymmetric unit. The protein is primarily alpha helical, with six helices in each subunit that comprise approximately 62 percent of the structure; there is no beta sheet. The dimeric structure of human interferon-gamma is stabilized by the intertwining of helices across the subunit interface with multiple intersubunit interactions.     

Collisionally activated decomposition mass spectrometry/mass spectrometry determination of organophosphorus pesticide residues in foods

Representative collisionally activated decomposition mass spectrometry/mass spectrometry spectra of omethoate, parathion, and azinphos-methyl pesticides are described. Crude and cleaned up extracts of strawberries or lettuce fortified at the 0.2 ppm level with omethoate, parathion, and azinphos-methyl were examined using the direct exposure probe. Cleaned up extracts produced better data because the large overburden of interfering coextractives was removed.     

Disease of geese caused by a new herpesvirus

A goose flock farmed outdoors in south-eastern Queensland suffered an outbreak of peracute disease with high death rate (97%). Small button ulcers and large plaques overlying lymphocyte aggregates were present on the mucosa of the small intestine of affected birds. Small white foci of necrosis and focal haemorrhages were seen in the livers. Numerous intranuclear inclusion bodies were observed microscopically in hepatocytes and a herpesvirus which grew rapidly in chicken kidney cells was isolated from tissues. Duck virus enteritis (DVE) was suspected but DVE antiserums failed to neutralise the virus. Further serological studies with a limited range of known avian herpesviruses have failed to identify the virus. Experimental transmission resulted in high mortality in geese (100%), lower mortality in ducklings and nil mortality in chickens. Surveillance studies showed no evidence of infection in domestic and wild birds beyond the original farm and the infection appears not to have been established in the area. Wild ducks, which were frequent visitors to the farm dam, were considered the most likely source of the infection.