Fibril assemblies in aqueous whey protein mixtures

Fibril formation in mixtures of whey proteins upon heating at pH 2 was investigated. Fibrils were found to coexist with other structures, such as spherulites. These spherulites consist of radially oriented fibrils. At total protein concentrations above 6 wt %, transparent gels were formed. Changing the ratio between the various whey proteins did not affect this gelation concentration as long as beta-lactoglobulin (beta-lg) was present, suggesting that beta-lg was dominant in the gelation. Pure alpha-lactalbumin and pure bovine serum albumin did not form fibrils, nor did they gel upon heating at pH 2 and 80 degrees C for up to 10 h. They did however induce a decrease in the beta-lg concentration needed for gel formation upon heating at pH 2. Our results suggest that beta-lg is the only fibril forming protein at the conditions used and that no mixed fibrils are formed.     

Alcohol and dietary fibre intakes affect circulating sex hormones among premenopausal women

BACKGROUND: The association of alcohol and fibre intake with breast cancer may be mediated by circulating sex hormone levels, which are predictors of breast cancer risk. OBJECTIVE: To evaluate the relationship of alcohol and dietary fibre intake with circulating sex hormone levels among premenopausal women. METHODS: A total of 205 premenopausal women completed a validated food-frequency questionnaire at baseline and after 2 years; blood samples taken at the same time were analysed for circulating sex hormone concentrations, including oestrone (E1), oestradiol (E2), free E2, progesterone, androstenedione and sex hormone-binding globulin, by radioimmunoassay. We used mixed models to estimate least-square means of sex hormone concentrations for alcohol intake categories and quartiles of dietary intake. RESULTS: After adjustment for covariates, alcohol consumption was moderately associated with higher circulating oestrogen levels; those who consumed more than one drink per day had 20% higher E2 (Ptrend=0.07) levels than non-drinkers. In contrast, higher dietary fibre intake was associated with lower serum levels of androstenedione (-8% between the lowest and highest quartiles of intake, Ptrend=0.06), but not oestrogens. Similarly, consumption of fruits (-12%, Ptrend=0.03), vegetables (-9%, Ptrend=0.15) and whole grains (-7%, Ptrend=0.07) showed inverse associations with androstenedione levels. CONCLUSIONS: The consistency of the observed differences in sex hormone levels associated with alcohol and fibre-rich foods indicates that these nutritional factors may affect sex hormone concentrations and play a role in breast cancer aetiology and prevention.     

Building on existing models from human medical education to develop a communication curriculum in veterinary medicine

Communication is a core clinical skill of veterinary medicine and one that needs to be taught and learned to the same degree as other clinical skills. To provide this education and essential expertise, veterinary schools in many countries, especially including North America, the United Kingdom, and Australia, have begun to develop programs and communication curricula. Human medical education, however, has 30 years' experience in developing communication curricula, and is thus an excellent resource upon which veterinary educators can build and shape their own communication programs. This article describes a skills-based communication course that has been successfully implemented for veterinary medical education at Ontario Veterinary College (OVC) and was based on the University of Calgary Faculty of Medicine's well-established program. The Calgary-Cambridge Guides and supporting textbooks provide the scaffolding for teaching, learning, and evaluation in both programs. Resources such as space and materials to support the OVC program were also patterned after Calgary's program. Communication skills, and the methods for teaching and learning them, are equally applicable for the needs of both human medicine and veterinary medicine. The research evidence from human medicine is also very applicable for veterinary medicine and provides it the leverage it needs to move forward. With this extensive base available, veterinary medicine is in a position to move communication skills training forward rapidly.     

Multiple outbreaks of severe acute BVDV in North America occurring between 1993 and 1995 linked to the same BVDV2 strain

The first reported outbreak of bovine viral diarrhea (BVD) in 1946 described a transmissible acute disease characterized by severe leukopenia, high fever, gastrointestinal erosions and hemorrhages. However, in the ensuing years, the most commonly observed acute form of BVD was clinically mild. There was limited viral shed and spread following these acute infections. This led to the assumptions that acute infections with BVD viruses (BVDV) were clinically unimportant, spread of the virus within a group was always due to the presence of a persistently infected animal and transmission between healthy immunocompetent cattle was insignificant. These assumptions were challenged when outbreaks of severe acute BVDV were observed in North America starting in the late 1980s. This study demonstrates that widespread outbreaks of severe acute BVD observed in 1993 in North America can be traced to a single strain of BVDV that apparently spread explosively following acute infection. These findings are notable in that they draw into question management of acute BVD infection, design of studies examining virulence and nomenclature used to identify strains for GenBank submission.     

Effect of stirring and seeding on whey protein fibril formation

The effect of stirring and seeding on the formation of fibrils in whey protein isolate (WPI) solutions was studied. More fibrils of a similar length are formed when WPI is stirred during heating at pH 2 and 80 degrees C compared to samples that were heated at rest. Addition of seeds did not show an additional effect compared to samples that were stirred. We propose a model for fibril formation, including an activation, nucleation, growth, and termination step. The activation and nucleation steps are the rate-determining steps. Fibril growth is relatively fast but terminates after prolonged heating. Two processes that possibly induce termination of fibril growth are hydrolysis of nonassembled monomers and inactivation of the growth ends of the fibrils. Stirring may break up immature fibrils, thus producing more active fibrils. Stirring also seems to accelerate the kinetics of fibril formation, resulting in an increase of the number of fibrils formed.     

Validation-study conclusions from dietary reports by fourth-grade children observed eating school meals are generalisable to dietary reports by comparable children not observed

OBJECTIVE: To investigate the effect of observing school meals on children's dietary reports. SUBJECTS AND SETTING: One hundred and twenty children randomly selected, but with half girls, from usual school-meal eaters among 312 volunteers (from all 443 fourth-grade children in six schools in one district). DESIGN: Children were assigned randomly to one of 12 conditions yielded by crossing observation status (observed; not observed), target period (previous day; prior 24 hours), and interview time (morning; afternoon; evening). RESULTS: Response variables included interview length, number of meals and snacks reported for the target period, and, for two school meals, number of meal components reported, importance-weighted number of items reported and kilocalories reported. These variables were transformed to principal components; two were retained (1, the school meal variables; 2, interview length and number of meals and snacks). Analyses of variance on principal component scores tested effects of observation status, target period, interview time and all interactions. Observation status did not affect scores on either retained principal component. Scores on Component 2 showed that more intake was reported in prior-24-hours interviews than in previous-day interviews. CONCLUSIONS: The effect of target period on reported intake indicates that the response variables were sufficiently reliable to detect manipulations. This, together with the finding that response variables did not depend on observation status, suggests that observation of school meals does not affect fourth-grade children's dietary reports, and that conclusions about dietary reports by fourth-grade children observed eating school meals in validation studies may be generalised to dietary reports by comparable children not observed.     

A RETROSPECTIVE STUDY INTO THE EFFECTS OF OPERATOR EXPERIENCE ON THE ACCURACY OF ULTRASOUND IN THE DIAGNOSIS OF GASTRIC NEOPLASIA IN DOGS

The accuracy of three diagnostic techniques in two separate time periods was examined. In the first time period, 18 dogs were referred to the University of Bristol with signs suggestive of gastric neoplasia. Of these 18 dogs, 7 had a positive diagnosis of gastric neoplasia from histopathology samples (38% prevalence). The sensitivity of ultrasound was found to be 42.9% with a specificity of 63.6%. A year later the study was repeated with 40 cases referred for investigation. Of these 40 dogs, 16 had a positive histopathologic diagnosis of gastric neoplasia (40% prevalence). At this time the sensitivity of ultrasound had increased to 81.3 % and the specificity had increased to 70.8 %. The increase in sensitivity was attributed to an increase in operator experience in the performance of the ultrasound examination. This improvement in sensitivity and experience resulted in a greater accuracy at detecting the presence of gastric neoplasia.     

Identification and quantification of flavonol glycosides in almond seedcoats using MALDI-TOF MS

Interest in the molecular composition of almonds is growing, due to their popularity in a wide variety of food formulations. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a powerful new technique that can be used to rapidly identify and quantify possible bioactive compounds in these popular tree nuts. Four flavonol glycosides were identified in almond seedcoats for the first time: isorhamnetin rutinoside, isorhamnetin glucoside, kaempferol rutinoside, and kaempferol glucoside. A MALDI-TOF MS methodology was developed using rutin (quercetin-3-rutinoside) as an internal standard to quantitatively determine each of the four flavonol glycosides. Results of MALDI-TOF MS analysis were verified by high performance liquid chromatography.     

Genetic variation in the <Emphasis Type="Italic">Crambe abyssinica - C. hispanica - C. glabrata</Emphasis> complex

Crambe abyssinica Hochst. ex R.E. Fries (n = 45) is an industrial oilseed crop that is high in erucic acid. It is most closely related to C. hispanica L. (n = 30) and C. glabrata DC. (n = 15), although the latter species is most often included in the synonymy of C. hispanica. The species complex extends throughout the Mediterranean region, Ethiopia and East Africa. Crambe abyssinica is endemic to Ethiopia, C. glabrata to Spain, Portugal and Morocco, and C. hispanica is distributed in the Mediterranean region and Middle East. The present study compared genetic relationships among C. abyssinica, C. hispanica and C. glabrata and attempted a taxonomic separation of them using traditional morphological traits, agronomic and seed quality data, chromosome number, and various molecular data sets including nuclear-DNA based RAPD data, chloroplast (cpDNA) restriction site data and ITS sequence data for the internal transcribed spacer region of the nuclear ribosomal DNA. The three species can be distinguished most reliably by chromosome number. Accessions could generally, but not always, be distinguished morphologically by plant branching pattern, fruit articulation and colour, leaf pubescence and leaf shape. cpDNA restriction site data and ITS sequence data, two relatively conserved DNA data sets, supported the recognition of C. glabrata as a distinct species separate from the C. hispanica/C. abyssinica accessions. Within the latter group, both RAPD data and field evaluation data revealed greater amounts of genetic variation in C. hispanica compared with accessions of C. abyssinica, with the latter included as a subset of C. hispanica. Crambe glabrata was genetically distinct for all data sets and warrants separate species status.