Centre for behavioural research in cancer

The Centre for Behavioural Research in Cancer (CBRC) is one of two research centres housed at the Anti-Cancer Council of Victoria, the other being an epidemiological research centre. The CBRC's main focus for research is in smoking behaviour. A feature of the Centre is its close organisational and professional links with Victoria's large publicly funded smoking prevention programme. This provides opportunities to conduct programme-related research, to influence the nature of tobacco reduction interventions and to evaluate outcomes.     

Membrane fractions of trypanosomes mimic the immunosuppressive and mitogenic effects of living parasites on the host

African trypanosomiasis in mice leads to profound changes in lymphoid tissues. In an attempt to define the nature of the trypanosome stimulus, we have studied the effect of radio-attenuated trypanosomes and their subcellular fractions in vivo. We find that relatively low doses of irradiated Trypanosoma brucei S42 injected into (CBA/H x C57B1/6)F1 mice mimicked the previously reported effects of infective parasites. 2 x 10(7) irradiated trypanosomes caused a greater than two-fold increase in spleen weight accompanied by a roughly 10-fold increase in background plaque forming cells (PFC) to sheep red blood cells (SRBC). The primary response to SRBC was significantly enhanced when priming was carried out on the day of trypanosome injection, but significantly suppressed when carried out 3 days later. Disruption of trypanosomes by freeze-thawing did not destroy their mitogenic or immunosuppressive activities. A membrane fraction collected by high speed centrifugation (150 000 x g) after removal of larger organelles at 12 000 x g retained both mitogenic and suppressive activities. The high speed supernatant lost the ability to enhance background PFC, but still caused partial immunosuppression with a much lower potency than the membrane pellet. Whether immunosuppression and enhanced PFC levels relate to the same parasite product is not clear as yet, but both effects can be ascribed to a membrane fraction of the parasite.     

Evidence of validity in a new method for measurement of dexterity in children and adolescents

Aim Many everyday activities involve manipulation of objects with the fingertips. Impaired performance in manipulative tasks is common in neurodevelopmental disorders. Thus accurate assessment of an individual’s ability to coordinate fingertip forces is important for planning treatment. We evaluated a recently developed assessment tool (the Strength–Dexterity Test), which is based on manipulation of unstable objects, in a paediatric population. Method A Rasch model was used to examine the validity and reliability of the Strength–Dexterity Test in a sample of 56 typically developing children and adolescents (30 males, 26 females; age range 4y 10mo–17y 3mo; mean age 9y 8mo, SD 3y 8mo). In addition, we examined how performance on this test relates to widely used tests for assessment of gross manual dexterity (assessed with the Box and Blocks Test) and finger strength measured with a pinch meter. Results The constructs measured with the 78‐item Strength–Dexterity Test include dexterity and strength, and form a unique unidimensional latent trait, named fingertip force coordination, that improves with age. The test has internal scale validity when applied to a typical paediatric population. Positive correlations (significant at p<0.001) were found among all three tests. Interpretation We provide preliminary evidence of construct validity in the Strength–Dexterity Test. Our findings suggest that this test has the potential to be developed into a promising tool for assessing dexterity in children.     

Non-mammalian “big” neurophysins — complete amino acid sequence of a two-domain MSEL-neurophysin from goose

Vasotocin-associated neurophysin (MSEL-neurophysin) has been purified from goose neurohypophysis through molecular sieving and high-pressure reverse-phase liquid chromatography (HPLC). The protein has a molecular mass (measured by SDS-polyacrylamide gel electrophoresis) of 17kDa in contrast to 10kDa found for the mammalian MSEL-neurophysins. Complete amino acid sequence (131 residues) has been determined mainly through tryptic or staphylococcal proteinase peptides derived from carboxyamido-methylated neurophysin, isolated by HPLC and microsequenced. N- and C-terminal sequences have been established by Edman degradation or action of carboxypeptidase Y, respectively, applied on the native protein. Goose MSEL-neurophysin is homologous to the two-domain “big” MSEL-neurophysin previously identified in the frog. It appears that in non-mammalian tetrapods, namely birds and amphibians, the proteolytic processing of the pro-vasotocin involves only one cleavage, releasing the hormone moiety and a “big” neurophysin with two domains homologous to mammalian MSEL-neurophysin and copeptin, respectively. Comparison of the avian protein with its mammalian and amphibian counterparts reveals that the first half of the polypeptide chain is evolutionarily much less variable than the second and that the goose protein resembles the frog protein much more than the mammalian one.     

Regional variations of muscle fibre characteristics in m. semitendinosus of growing cattle

The objectives of the present study were to elaborate an intra-muscular profile of metabolic enzyme equipment, contractile and morphometric features along the longitudinal axis of m. semitendinosus at various ages throughout the growth phase. Thirty-seven male Montbeliard cattle, about half of them castrated, were representatively allocated to various slaughter dates, scheduled at 4, 8, 12 and16 months of age. Samples were collected from proximal, medial and distal locations of m. semitendinosus. Isocitrate dehydrogenase (aerobic metabolism) and lactate dehydrogenase (anaerobic metabolism) were measured spectrophotometrically. Contractile muscle type was classified by quantification of myosin heavy chain I isoform proportion using the sensitive enzyme-linked immunosorbent assay. Mean muscle fibre area was obtained on histologically-stained cross-sections utilizing animage analysis system. Our results indicated the existence of a regular intra-muscular pattern of muscle fibre traits along the length of m. semitendinosus, with decreasing glycolytic activities and concomitantly an increase in oxidative capacity towards the distal extremity. The metabolic characteristics were in good agreement with decreasing cross-sectional muscle fibre areas and the slow myosin heavy chain I isoform proportion becoming gradually more abundant from proximal to distal regions of the muscle. Moreover, the observed gradient was found to be closely related to age and diminished with advanced physiological maturity. At the final slaughter age (16 months) no differences among the distinct portions were detected, m. semitendinosus was longitudinally homogeneous in all the characteristics studied This revised version was published online in July 2006 with corrections to the Cover Date.     

Scabies with Clinical Features and Positive Darier Sign Mimicking Mastocytosis

Abstract:  Scabies is a common human parasitic infection in infants and children. But diagnosis pitfalls are frequent in infants, in whom the clinical presentation is usually atypical and different from adults. We report a misleading case of a 5-month-old child, who presented with pruritic brown–red macules of the trunk showing a positive Darier's sign, suggestive of an urticaria pigmentosa.     

CARBOHYDRATE-DEFICIENT TRANSFERRIN AS A SCREENING MARKER FOR DRINKING IN A GENERAL HOSPITAL POPULATION

We investigated the usefulness of the laboratory marker of alcoholconsumption carbohydrate-deficient transferrin (CDT) in 101consecutively admitted patients in a surgical and internal medicalward of a hospital in a rural wine-growing area. Four majoraspects were considered: the influence of liver disease, themethod of expression of CDT values (relative % vs absolute units/1),level and pattern of alcohol consumption and comparison with     

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY IMPROVES DIAGNOSTIC EFFICIENCY OF CARBOHYDRATE-DEFICIENT TRANSFERRIN

Carbohydrate-deficient transferrin (CDT) is considered a usefulbiochemical marker of regular high alcohol intake. CDT was measuredin the sera of 51 alcohol abusers, 20 patients with nonalcoholicliver disease and 30 healthy controls with an alcohol intakeof <30g/day. The mean CDT levels of these three groups respectivelywere determined with high-performance liquid chromatography(HPLC; 4.6 ± 5.2%; 0.7 ± 0.2%; 0.7 ± 0.2%)and with a radioimmunoassay after microcolumn anion-exchangechromatography (MAEC/RIA; 34.2 ± 26.9 U/1; 16.9 ±3.8 U/1; 18.0 ± 5.7 U/1). CDT levels in patients withsevere alcohol abuse (161.6 ± 96.4g/day) were significantlyhigher than in the two other groups under investigation (P <0.0001). In heavily drinking subjects, the mean daily alcoholintake correlated with aspartate aminotransferase levels (ASAT)but not with the CDT levels determined either with HPLC or MAEC/RIA.With both methods, the CDT levels were slightly higher in patientswith an ASAT concentration >30 U/1, which may indicate anadvanced liver damage (P < 0.05). Analysis of receiver-operatingcharacteristic (ROC) plots demonstrated that the diagnosticaccuracy of the HPLC method, which determines the relative amountof CDT, was significantly higher than the established MAEC/RIAmethod, which measures the absolute amount of CDT (area underthe ROC curve: 0.95 ± 0.02 vs 0.73 ± 0.05; P <0.0001). At a specificity of >95%, the sensitivity of CDTdetermined with HPLC and MAEC/RIA was 80 and 47%, respectively.In addition, HPLC may be a useful and reliable method for thedetermination of this important biochemical marker, since theHPLC chromatogram is a visible document of the successful isotransferrinseparation and measurement.     

Circadian variation in the circumstances of delivery in a population at low obstetric risk

While circadian variations in birth and perinatal mortalityrates have previously been described in the literature, thereasons behind these observed rhythms remain unclear. The principalhypothetical causes include variations in obstetric practicesand an association between the time of birth and biologicalparameters. In order to explore this issue we analysed the distributionpatterns for time and day of birth, as well as circadian variationsin maternal characteristics, obstetric practices and neonatalrisk in a population at low obstetric risk. The study populationincluded 685 low-risk pregnant women consecutively admittedat an early stage of labour to six maternity units. The resultsshowed hourly variations in the birth rate and circadian variationsin obstetric practices that might explain the hourly patternobserved for the birth rate. By contrast, the frequency of apositive neonatal risk indicator was uniform across all timecategories in this population at low obstetric risk.