Pre-analytical requirements

Correct test selection: a test must have the potential to alter patient management and have the specificity and sensitivity appropriate to the pretest probability of disease. Correct dynamic test procedure: dynamic tests may assist diagnosis and protocols must be readily available. Correct patient preparation: fasting, or other patient preparation, may reduce variability. Clear communication, to both patients and staff, of any such requirements is essential. Correct sample collection: the tube type (for blood) or container (for urine) must be appropriate for the analyte; there must be sufficient volume, avoidance of venous stasis, contaminants and haemolysis; and adequate labelling. Correct sample handling: the time and temperature before and after separation, and the centrifugation and separation procedures, must be suitable for the analyte. Accept/reject criteria must be defined. Methods require thorough evaluation of patient-related pre-analytical factors, and quantification of the effects of time, temperature, haemolysis, anticoagulant type and minimum allowable volume on sample suitability.     

The influence of visual stimulation on the behaviour of cats housed in a rescue shelter

This study explored the influence of 5 types of visual stimulation (1 control condition [no visual stimulation] and 4 experimental conditions [blank television screen; and, televised images depicting humans, inanimate movement, animate movement]) on the behaviour of 125 cats housed in a rescue shelter. Twenty-five cats were randomly assigned to one of the five conditions of visual stimulation for 3 h a day for 3 days. Each cat's behaviour was recorded every 5 min throughout each day of exposure to the visual stimuli. Cats spent relatively little of the total observation time (6.10%) looking at the television monitors. Animals exposed to the programmes depicting animate and inanimate forms of movement spent significantly more of their time looking at the monitors than those exposed to the moving images of humans or the blank screen. The amount of attention that the cats directed towards the television monitors decreased significantly across their 3 h of daily presentation, suggesting habituation. Certain components of the cats’ behaviour were influenced by visual stimulation. Animals in the animate movement condition spent significantly less time sleeping, and displayed a non-significant trend to spend more time resting, and in the exercise area of their pens, than those in the other conditions of visual stimulation. Overall, the results from this study suggest that visual stimulation in the form of two-dimensional video-tape sequences, notably that combining elements of prey items and linear movement, may hold some enrichment potential for domestic cats housed in rescue shelters. Such animals, however, may not benefit from this type of enrichment to the same degree as species with more well-developed visual systems, such as primates.     

Spatial and temporal segregation of auditory and vestibular neurons in the otic placode

The otic placode generates the auditory and vestibular sense organs and their afferent neurons; however, how auditory and vestibular fates are specified is unknown. We have generated a fate map of the otic placode and show that precursors for vestibular and auditory cells are regionally segregated in the otic epithelium. The anterior-lateral portion of the otic placode generates vestibular neurons, whereas the posterior-medial region gives rise to auditory neurons. Precursors for vestibular and auditory sense organs show the same distribution. Thus, different regions of the otic placode correspond to particular sense organs and their innervating neurons. Neurons from contiguous domains rarely intermingle suggesting that the regional organisation of the otic placode dictates positional cues to otic neurons. But, in addition, vestibular and cochlear neurogenesis also follows a stereotyped temporal pattern. Precursors from the anterior-lateral otic placode delaminate earlier than those from its medial-posterior portion. The expression of the proneural genes NeuroM and NeuroD reflects the sequence of neuroblast formation and differentiation. Both genes are transiently expressed in vestibular and then in cochlear neuroblasts, while differentiated neurons express Islet1, Tuj1 and TrkC, but not NeuroM or NeuroD. Together, our results indicate that the position of precursors within the otic placode confers identity to sensory organs and to the corresponding otic neurons. In addition, positional information is integrated with temporal cues that coordinate neurogenesis and sensory differentiation.     

The molecular structure and physical properties of elastin fibers as revealed by Raman microspectroscopy

Raman microspectroscopy has been used to investigate the structure of alpha-elastin and fibrous elastin from ligament and aorta, and to explore changes associated with mechanical strain and temperature. Although no vibrational modes associated with cross-linking of the fibers could be identified, the secondary structure of dehydrated fibrous elastin was significantly different from alpha-elastin. The former differed from previous experimental measurements, but was close to the theoretical predictions with 36% beta-structures, 46% unordered, and 18% alpha-helix. alpha-Elastin contained 29% beta-structures, 53% unordered, and 18% alpha-helix. In nuchal fibers the amide I mode was polarized, consistent with the peptide bond. Strains of up to 60% in ligament fiber bundles resulted in no significant shifts in peak position or in secondary structure. Polarization measurements revealed that the peptide bonds and several side chains re-orientated closer to the fiber axis. Heating nuchal fibers to 60 degrees C to increase the energetic component of the elasticity was associated with a 30% increase in the proportion of beta-structures in the amide I band, a 50% increase in the amide III band, and a 50% reduction in the signal from bound water. (c) 2008 Wiley Periodicals, Inc. Biopolymers 89: 931-940, 2008.This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com.     

Parental transmission of <Emphasis Type="Italic">HLA-DRB1*15 </Emphasis>in multiple sclerosis

Chen et al. found that the CA haplotype of protein C -1654C/T and -1641G/A was associated with increased risk of death and organ dysfunction in Chinese Han patients with severe sepsis (Hum Genet 123:281–287, 2008). We similarly tested for association of the C allele of protein C 673 T/C (rs2069912) (linkage disequilibrium with the CA haplotype, D′ = 100%) in a cohort of 100 North American East Asians with severe sepsis. The C allele was associated with increased mortality and organ dysfunction, consistent with Chen et al. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Support: Sirius Genomics Inc., Canadian Institutes of Health Research. Keith R. Walley is a Michael Smith Foundation for Health Research Distinguished Scholar.     

The intrinsic resistance of female hearts to an ischemic insult is abrogated in primary cardiac hypertrophy

Important sex differences in cardiovascular disease outcomes exist, including conditions of hypertrophic cardiomyopathy and cardiac ischemia. Studies of sex differences in the extent to which load-independent (primary) hypertrophy modulates the response to ischemia-reperfusion (I/R) damage have not been characterized. We have previously described a model of primary genetic cardiac hypertrophy, the hypertrophic heart rat (HHR). In this study the sex differences in HHR cardiac function and responses to I/R [compared to control normal heart rat (NHR)] were investigated ex vivo. The ventricular weight index was markedly increased in HHR female (7.82 +/- 0.49 vs. 4.80 +/- 0.10 mg/g; P < 0.05) and male (5.76 +/- 0.22 vs. 4.62 +/- 0.07 mg/g; P < 0.05) hearts. Female hearts of both strains exhibited a reduced basal contractility compared with strain-matched males [maximum first derivative of pressure (dP/dt(max)): NHR, 4,036 +/- 171 vs. 4,258 +/- 152 mmHg/s; and HHR, 3,974 +/- 160 vs. 4,540 +/- 259 mmHg/s; P < 0.05]. HHR hearts were more susceptible to I/R (I = 25 min, and R = 30 min) injury than NHR hearts (decreased functional recovery, and increased lactate dehydrogenase efflux). Female NHR hearts exhibited a significantly greater recovery (dP/dt(max)) post-I/R relative to male NHR (95.0 +/- 12.2% vs. 60.5 +/- 9.4%), a resistance to postischemic dysfunction not evident in female HHR (29.0 +/- 5.6% vs. 25.9 +/- 6.3%). Ventricular fibrillation was suppressed, and expression levels of Akt and ERK1/2 were selectively elevated in female NHR hearts. Thus the occurrence of load-independent primary cardiac hypertrophy undermines the intrinsic resistance of female hearts to I/R insult, with the observed abrogation of endogenous cardioprotective signaling pathways consistent with a potential mechanistic role in this loss of protection.     

Assessment of four biodiesel production processes using HYSYS.Plant

Four continuous biodiesel processes were designed and simulated in HYSYS. The first two employed traditional homogeneous alkali and acid catalysts. The third and fourth processes used a heterogeneous acid catalyst and a supercritical method to convert a waste vegetable oil feedstock into biodiesel. While all four processes were capable of producing biodiesel at high purity, the heterogeneous and supercritical processes were the least complex and had the smallest number of unit operations. Material and energy flows, as well as sized unit operation blocks, were used to conduct an economic assessment of each process. Total capital investment, total manufacturing cost and after tax rate-of-return were calculated for each process. The heterogeneous acid catalyst process had the lowest total capital investment and manufacturing costs, and had the only positive after tax rate-of-return.