Novel symmetric bis-benzimidazoles: Synthesis, DNA/RNA binding and antitrypanosomal activity.

The novel benzimidazol-2-yl-fur-5-yl-(1,2,3)-triazolyl dimeric series with aliphatic and aromatic central linkers was successfully prepared with the aim of assessing binding affinity to DNA/RNA and antitrypanosomal activity. UV-Visible spectroscopy, thermal denaturation showed interaction of heterocyclic bis-amidines with ctDNA. Circular dichroism studies indicated uniform orientation of heterocyclic bis-amidines along the chiral double helix axis, revealing minor groove binding as the dominant binding mode. The amidino fragment and 1,4-bis(oxymethylene)phenyl spacer were the main determinants of activity against Trypanosoma brucei. The bis-benzimidazole imidazoline 15c, which had antitrypanosomal potency in the submicromolar range and DNA interacting properties, emerged as a candidate for further structural optimization to obtain more effective agents to combat trypanosome infections.

An automated approach to the classification of impact spatter and cast-off bloodstain patterns.

In the forensic discipline of bloodstain pattern analysis, it has been suggested that there is a blurred boundary between characterising the features of a bloodstain pattern and determining the mechanism(s) that led to its deposition. This study proposes that bloodstain pattern classification can become a distinct and logical process by implementing an automated approach. To do this, an automated bloodstain pattern recognition system was developed to enable the distinction of two types of spatter bloodstain patterns. First, global pattern features based on common bloodstain pattern properties were extracted from laboratory-generated impact spatter and cast-off bloodstain patterns. Following this, automated feature selection methods were used to identify the combination of features that best distinguished the two bloodstain pattern types. This eventually led to the training and testing of a Fisher quadratic discriminant classifier using separate subsets of the generated bloodstain patterns. When applied to the training dataset, a 100% classification precision resulted. An independent dataset comprising of bloodstain patterns generated on paint and wallpaper substrates were used to validate the performance of the classifier. An error rate of 2% was obtained when the classifier was applied to these bloodstain patterns. This automated bloodstain pattern recognition system offers considerable promise as an objective classification methodology which up to now, the discipline has lacked. With further refinement, including testing it over a wider range of bloodstain patterns, it could provide valuable quantitative data to support analysts in their task of classifying bloodstain patterns.

An eye tracking study of bloodstain pattern analysts during pattern classification.

Bloodstain pattern analysis (BPA) is the forensic discipline concerned with the classification and interpretation of bloodstains and bloodstain patterns at the crime scene. At present, it is unclear exactly which stain or pattern properties and their associated values are most relevant to analysts when classifying a bloodstain pattern. Eye tracking technology has been widely used to investigate human perception and cognition. Its application to forensics, however, is limited. This is the first study to use eye tracking as a tool for gaining access to the mindset of the bloodstain pattern expert. An eye tracking method was used to follow the gaze of 24 bloodstain pattern analysts during an assigned task of classifying a laboratory-generated test bloodstain pattern. With the aid of an automated image-processing methodology, the properties of selected features of the pattern were quantified leading to the delineation of areas of interest (AOIs). Eye tracking data were collected for each AOI and combined with verbal statements made by analysts after the classification task to determine the critical range of values for relevant diagnostic features. Eye-tracking data indicated that there were four main regions of the pattern that analysts were most interested in. Within each region, individual elements or groups of elements that exhibited features associated with directionality, size, colour and shape appeared to capture the most interest of analysts during the classification task. The study showed that the eye movements of trained bloodstain pattern experts and their verbal descriptions of a pattern were well correlated.

Nitrogen deprivation in Fusarium oxysporum promotes mycotoxin production via intermediates in the Krebs cycle and unreported methylmalonyl-CoA mutase activity.

INTRODUCTION: Fusarium oxysporum has a high affinity for lignin and cellulose-based substrates and is known to grow in a wide range of environments. It is these properties and its ability to produce mycotoxins that have contributed to its pathogenicity in cereal crops that can affect human and animal health when ingested. OBJECTIVES: Identify the mechanisms of mycotoxin production and map the functional output of F. oxysporum under varying growth conditions. METHODS: Liquid and gas-based chromatography coupled with mass spectrometry was used to identify and map the untargeted metabolic pathway of F. oxysporum grown using nitrogen limited and organic/inorganic nitrogen supplemented media. RESULTS: Over 1300 metabolites were identified, relating to 42 metabolic pathways. Of these, 520 metabolites merged at pyruvate (glycolysis), succinate (Krebs cycle) and aspartate-glutamate metabolic pathways. CoA depletion at the growth stage triggered the initiation of fatty acid and branched amino acid degradation. This in turn activated propionyl CoA carnitine acetyltransferase enzymes, resulting in nitrogen preservation (urea, putrescine and organic acids end-products). CoA then transferred into the TCA cycle via previously unreported ß-alanine and propionyl CoA metabolic pathways, the latter likely being a novel methylmalonyl-CoA mutase activity for F. oxysporum. CONCLUSIONS: The lower supplementation of inorganic nitrogen compounds (≤ 50 mM) and the elimination of nitrates/organic nitrogen sources resulted in TCA autophagy events that boosted mycotoxin-based metabolism and decreased overall F. oxysporum growth. Such knowledge of functional mycotoxin production can be used to supplement agricultural crops and reduce the risk of mycotoxin contamination in human and animal food supplies.

Experimental measurement of breath exit velocity and expirated bloodstain patterns produced under different exhalation mechanisms.

In an attempt to obtain a deeper understanding of the factors which determine the characteristics of expirated bloodstain patterns, the mechanism of formation of airborne droplets was studied. Hot wire anemometry measured air velocity, 25 mm from the lips, for 31 individuals spitting, coughing and blowing. Expirated stains were produced by the same mechanisms performed by one individual with different volumes of a synthetic blood substitute in their mouth. The atomization of the liquid at the lips was captured with high-speed video, and the resulting stain patterns were captured on paper targets. Peak air velocities varied for blowing (6 to 64 m/s), spitting (1 to 64 m/s) and coughing (1 to 47 m/s), with mean values of 12 m/s (blowing), 7 m/s (spitting) and 4 m/s (coughing). There was a large (55-65%) variation between individuals in air velocity produced, as well as variation between trials for a single individual (25-35%). Spitting and blowing involved similar lip shapes. Blowing had a longer duration of airflow, though it is not the duration but the peak velocity at the beginning of the air motion which appears to control the atomization of blood in the mouth and thus stain formation. Spitting could project quantities of drops at least 1600 mm. Coughing had a shorter range of near 500 mm, with a few droplets travelling further. All mechanisms could spread drops over an angle >45°. Spitting was the most effective for projecting drops of blood from the mouth, due to its combination of chest motion and mouth shape producing strong air velocities. No unique method was found of inferring the physical action (spitting, coughing or blowing) from characteristics of the pattern, except possibly distance travelled. Diameter range in expirated bloodstains varied from very small (<1 mm) in a dense formation to several millimetres. No unique method was found of discriminating expirated patterns from gunshot or impact patterns on stain shape alone. Only 20% of the expirated patterns produced in this study contained identifiable bubble rings or beaded stains.

Experimental and computational investigation of the trajectories of blood drops ejected from the nose.

Blood expirated from the nose may leave a characteristic bloodstain at a crime scene which can provide important clues for reconstructing events during a violent assault. Little research has been done on the typical velocities, trajectories and size distribution that can be expected from expirated blood. An experimental fluid dynamics technique known as stereoscopic particle image velocimetry is used in this work to obtain the air velocity field inside and outside the nostrils during exhalation. A numerical model was then used to compute the trajectory of blood drops of 0.5 and 2 mm. The drops were tracked until ground plane impact below the nostril exit. Three heights were investigated, 1.5, 1.6 and 1.7 m. For an expiration flow rate of 32 l/min in vivo, there is a maximum exit velocity from the nostril of approximately 4 m/s, with a 0.5 m/s difference between nostrils. After the drops have traversed the distances investigated, drops of 0.5 and 2 mm in diameter from both nostrils are at a similar velocity. This implies that the gravitational acceleration after the drops leave the jet has the most influence on velocity. It is however shown that exit velocity does affect impact location. Drop size affects both impact location and impact velocity. An increase in height increases the distance traversed. Compared to the 2-mm drop, the 0.5 mm had a lower impact velocity, but its impact location in the ground plane was further from the nostril exit. Understanding the physics of expirated blood flight allows better interpretation of expirated stains at crime scenes.

Simulating backspatter of blood from cranial gunshot wounds using pig models.

Few studies have examined the biomechanical basis for backspatter from cranial gunshot wounds. Backspatter is material which travels against the direction of fire following ejection from a gunshot entrance wound. Our paper focuses on the use of animals for reconstructing this phenomenon. Five live pigs and several slaughtered pigs were shot using either 9 × 19 mm, 115 grain, full metal jacketed ammunition or .22 long rifle, 40 grain, lead, round-nose ammunition. A high-speed camera was used to record the entrance wound formation and backspatter. A small amount of backspattered material was produced with all targets, and blood backspatter was seen in a few cases. However, we conclude that our model provides an understanding of the phenomenon of backspatter and the physical mechanisms associated with it. The various components of the mechanism of backspatter formation are complex and overlap. The principle mechanism observed in pig cranial gunshots was the high-speed impact response of the skin overlying the skull bone. This study has also produced evidence supporting the view that backspatter can result from the splashing of superficial blood if it is already present on the skin. Subcutaneous gas effects have been demonstrated for backspatter from contact shots. There has been no clear evidence of the role of the collapse of a temporary cavity within the brain.

Visualization of the air ejected from the temporary cavity in brain and tissue simulants during gunshot wounding.

One hypothesis for the physical mechanism responsible for backspatter during cranial gunshot wounding is that air is ejected by the collapse of the temporary cavity formed around the bullet path. Using bovine and ovine heads and simulant materials, evidence of this ejection was sought by measuring the velocity of the air that was drawn in and ejected from the cavity in front of the wound channel after bullet impact. A laminar flow of fog-laden air was arranged in front of the wound channel and two high speed cameras recording at 30,000 frames/second captured the air motion. All samples were shot with standard 9 mm × 19 mm FMJ ammunition. Different concentrations of ballistic gelatine were used to characterize the effect of elasticity of the material on the velocity of the air. Fresh bovine and ovine heads were shot with the same experimental set up to investigate if there was induction of air into, and ejection of air from the entrance wounds. The results show, for the first time, that the temporary cavity does eject air in gelatine. The velocity of in-drawn air for 3, 5 and 10% concentration of gelatine was 81, 76 and 65 m/s respectively and the velocity of ejected air for 5 and 10% concentration of gelatine were 43 and 72 m/s respectively. The results show that when the concentration of gelatine is increased, the velocity of the air drawn into the cavity decreases and the velocity of the ejected air increases. However, no ejection was observed in 3% gelatine, ovine or bovine heads. Although ejection of air was not observed, ejection of brain from the wound channel was seen. Using the velocity of the ejected brain, the minimum intracranial pressure required to eject the brain tissue was estimated to be 712 kPa and 468 kPa for the sheep and bovine heads respectively.

Experimental validation of a numerical model for predicting the trajectory of blood drops in typical crime scene conditions, including droplet deformation and breakup, with a study of the effect of indoor air currents and wind on typical spatter drop trajectories.

Bloodstain Pattern Analysis (BPA) provides information about events during an assault, e.g. location of participants, weapon type and number of blows. To extract the maximum information from spatter stains, the size, velocity and direction of the drop that produces each stain, and forces acting during flight, must be known. A numerical scheme for accurate modeling of blood drop flight, in typical crime scene conditions, including droplet oscillation, deformation and in-flight disintegration, was developed and validated against analytical and experimental data including passive blood drop oscillations, deformation at terminal velocity, cast-off and impact drop deformation and breakup features. 4th order Runge-Kutta timestepping was used with the Taylor Analogy Breakup (TAB) model and Pilch and Erdman's (1987) expression for breakup time. Experimental data for terminal velocities, oscillations, and deformation was obtained via digital high-speed imaging. A single model was found to describe drop behavior accurately in passive, cast off and impact scenarios. Terminal velocities of typical passive drops falling up to 8m, distances and times required to reach them were predicted within 5%. Initial oscillations of passive blood drops with diameters of 1mm

Blood drop size in passive dripping from weapons.

Passive dripping, the slow dripping of blood under gravity, is responsible for some bloodstains found at crime scenes, particularly drip trails left by a person moving through the scene. Previous work by other authors has established relationships, under ideal conditions, between the size of the stain, the number of spines and satellite stains, the roughness of the surface, the size of the blood droplet and the height from which it falls. To apply these relationships to infer the height of fall requires independent knowledge of the size of the droplet. This work aims to measure the size of droplets falling from objects representative of hand-held weapons. Pig blood was used, with density, surface tension and viscosity controlled to fall within the normal range for human blood. Distilled water was also tested as a reference. Drips were formed from stainless steel objects with different roughnesses including cylinders of diameter between 10 and 100 mm, and flat plates. Small radius objects including a knife and a wrench were also tested. High speed images of the falling drops were captured. The primary blood drop size ranged from 4.15±0.11 mm up to 6.15±0.15 mm (depending on the object), with the smaller values from sharper objects. The primary drop size correlated only weakly with surface roughness, over the roughness range studied. The number of accompanying droplets increased with the object size, but no significant correlation with surface texture was observed. Dripping of blood produced slightly smaller drops, with more accompanying droplets, than dripping water.

Reversion-reporter transgenes to analyze all six base-substitution pathways in Arabidopsis.

To expand the repertoire of Arabidopsis (Arabidopsis thaliana) mutation-reporter transgenes, we constructed six mutant alleles in the same codon of the ß-glucuronidase-encoding GUS transgene. Each allele reverts to GUS+ only via a particular one of the six transition/transversion pathways. AcV5 epitope tags, fused carboxyl terminal to the inactive GUS- proteins, enabled semiquantitative immunoassays in plant protein extracts. Spontaneous G:C→T:A transversions, previously not measured using reporter transgenes, were quite frequent. This may reflect mispairing of adenine with 8-oxoguanine in DNA attacked by endogenous oxyradicals. Spontaneous G:C→A:T was modest and other reversions were relatively low, as reported previously. Frequencies of ultraviolet C-induced TT→TC and TC→TT reversions were both high. With increased transgene copy number, spontaneous G:C→T:A reversions increased but ultraviolet C-induced reversions decreased. Frequencies of some reversion events were reduced among T4 versus T3 generation plants. Based on these and other analyses of sources of experimental variation, we propose guidelines for the employment of these lines to study genotoxic stress in planta.

Iron metabolism in trypanosomatids, and its crucial role in infection.

Iron is almost ubiquitous in living organisms due to the utility of its redox chemistry. It is also dangerous as it can catalyse the formation of reactive free radicals - a classical double-edged sword. In this review, we examine the uptake and usage of iron by trypanosomatids and discuss how modulation of host iron metabolism plays an important role in the protective response. Trypanosomatids require iron for crucial processes including DNA replication, antioxidant defence, mitochondrial respiration, synthesis of the modified base J and, in African trypanosomes, the alternative oxidase. The source of iron varies between species. Bloodstream-form African trypanosomes acquire iron from their host by uptake of transferrin, and Leishmania amazonensis expresses a ZIP family cation transporter in the plasma membrane. In other trypanosomatids, iron uptake has been poorly characterized. Iron-withholding responses by the host can be a major determinant of disease outcome. Their role in trypanosomatid infections is becoming apparent. For example, the cytosolic sequestration properties of NRAMP1, confer resistance against leishmaniasis. Conversely, cytoplasmic sequestration of iron may be favourable rather than detrimental to Trypanosoma cruzi. The central role of iron in both parasite metabolism and the host response is attracting interest as a possible point of therapeutic intervention.

Effect of laundering on blunt force impact damage in fabrics.

Blunt force assault is a growing issue worldwide. In New Zealand, recorded cases of grievous blunt force assault increased steadily from 1011 in 1999 to 2139 in 2008. In many cases of blunt force assault victims are struck on parts of their body covered by clothing, yet the use of damage to apparel as forensic evidence largely appears to have been overlooked. The current research investigated blunt force impact (BFI) damage in common apparel fabrics and the effects prior and post-laundering had on this damage. Two 100% cotton fabrics (single jersey knit, bull drill) were impacted as single and double layers using an impactor representative of a hammer face, the force transmitted through specimens was measured and impulse calculated. Impacting and laundering were completed cumulatively to establish the effects of impact damage on new, dimensionally stable (laundered 6 times) and aged fabrics (laundered up to 30 times), and the effects of laundering on impacted specimens. BFI left recognisable patterns of damage in specimens, although the extent of this damage varied. Laundering after the impact event altered the visible and microscopic damage. Laundering previously impacted fabrics produced holes in some specimens and some fibres exhibited failure characteristic of blunt force impact.

Forensic evidence in apparel fabrics due to stab events.

Stab injuries and fatalities have been reported to be the most common crimes of violence in several countries, particularly in those where access to firearms is restricted [J.M. Taupin, F.-P. Adolf, J. Robertson, Examination of damage to textiles, in: J. Robertson, M. Grieve (Eds.), Forensic Examination of Fibres, CRC Press, United States of America, 1999, pp. 65-87; A.C. Hunt, R.J. Cowling, Murder by stabbing, Forensic Sci. Int. 52 (1991) 107-112; D.A. Rouse, Patterns of stab wounds: a six year study, Med. Sci. Law 34 (1994) 67-71]. Analysis of damaged apparel may provide important information about the cause of death and the events leading up to and after the victim's final moments [M.T. Pailthorpe, N.A.G. Johnson, The private forensic scientist and the criminal justice system, in: D. Biles, J. Vernon (Eds.), Private Sector and Community Involvement in the Criminal Justice System: Conference Proceedings, vol. 23, Australian Institute of Criminology, Wellington, 1994, 231-240]. A high proportion of stab wounds occur in the chest and as this area is generally clothed many sharp force cases involve damage to fabrics [J.M. Taupin, F.-P. Adolf, J. Robertson, Examination of damage to textiles, in: J. Robertson, M. Grieve (Eds.), Forensic Examination of Fibres, CRC Press, United States of America, 1999, pp. 65-87; A.C. Hunt, R.J. Cowling, Murder by stabbing, Forensic Sci. Int. 52 (1991) 107-112; D.A. Rouse, Patterns of stab wounds: a six year study, Med. Sci. Law 34 (1994) 67-71]. The structural stabilisation and degradation of fabric due to laundering significantly alters fabric properties [S.E. Gore, R.M. Laing, C.A. Wilson, D.J. Carr, B.E. Niven, Standardizing a pre-treatment cleaning procedure and effects of application on apparel fabrics, Text. Res. J. 76 (2006) 455-464], yet the effect of such on severance morphology does not appear to have been investigated. In this work the effect of blade type (hunting knife, kitchen knife, screwdriver) on new and laundered apparel fabrics was investigated. Two approaches were used (i) a human participant trial, and (ii) guided drop testing (using an impact rig). Force-time plots from the human participant trials were matched to those from the impact rig. Information on severance morphology was obtained using visual analysis techniques. Blades could be differentiated and directionality estimated by observing differences in severance shape and size, the degree of fabric distortion, the position of severed yarn ends, loop snippets, curled yarns, planar array and the morphology of fractured fibres. Fabric construction had a visible effect on severance morphology. Pre-impact degradation via laundering hindered the ability to link fractured fibre ends to a source of damage by altering morphology and increasing the variability. The correlation between blade height and severance length was weak, attributed to elastic deformation and recovery. The impact rig was a valuable tool in the reconstruction of textile damage. Damage was consistent when inflicted using a human participant trial and the impact rig, although more variable in the former. The advantage of the impact rig lies in the ability to produce a severance typical of the blade in question, under controlled conditions, in a reproducible manner.

Comparative outcomes following endoscopic ureteral detachment and formal bladder cuff excision in open nephroureterectomy for upper urinary tract transitional cell carcinoma.

PURPOSE: The introduction of laparoscopic nephroureterectomy highlights the need for the critical appraisal of approaches to the distal ureter at surgery for upper tract transitional cell carcinoma. We compared differences after endoscopic ureteral detachment and open bladder cuff excision in nephroureterectomy. MATERIALS AND METHODS: A total of 138 patients underwent open nephroureterectomy for upper urinary tract transitional cell carcinoma from 1982 to 2005 with a median followup of 43 months. Of these patients 90 underwent endoscopic ureteral detachment and 48 underwent bladder cuff excision. Demographic, perioperative and oncological outcome data were collected in all cases. Statistical analyses were performed using the Student t test, chi-square and log rank tests, and logistic and Cox regression. RESULTS: Mean operative duration was significantly lower in the endoscopic detachment group than in the bladder cuff group (p <0.01). There were 49 (54.4%) bladder recurrences in the endoscopic detachment group, of which 8 (16.3%) were muscle invasive and 3 (3.3%) developed at the resection site. There were 23 (47.9%) bladder recurrences in the bladder cuff group, of which 3 (13.0%) were muscle invasive and 2 (4.2%) developed at the resection site. All 5 resection site tumors occurred after excision of muscle invasive distal ureteral tumors and 4 of these had positive margins. There were no differences in recurrence-free survival or disease specific survival between the groups. Operation subtype did not predict oncological outcome on univariate or multivariate analysis. CONCLUSIONS: Endoscopic ureteral detachment reduces operative duration and is associated with equivalent oncological outcomes compared with open bladder cuff excision in nephroureterectomy. Caution should be exercised in patients with low ureteral tumors.

Depressive symptoms and outcome of coronary artery bypass grafting.

BACKGROUND: Depressive symptoms are an independent risk factor for outcome in patients with cardiac disease, but their effect on outcome among patients undergoing coronary artery bypass grafting is not well understood. OBJECTIVES: To determine whether or not clinical variables including length of stay, readmission rates, and mortality are related to patients' level of depressive symptoms before and after coronary artery bypass grafting. METHODS: An observational, longitudinal design was used. The Medical Outcomes Study 36-item short-form health survey was used to collect data on depressive symptoms in 416 patients undergoing coronary artery bypass grafting. The distribution of depressive symptoms was correlated with length of stay after the procedure, readmission, and mortality. RESULTS: The level of depressive symptoms before coronary artery bypass grafting correlated with the level of depressive symptoms at 6 weeks follow-up, both for the individual items "feeling down in the dumps" (r = 0.24, P = .009) and "feeling downhearted" (r = 0.36, P < .001) and for the overall score on the Mental Health scale (r = 0.40, P < .001). Feeling down in the dumps (P = .007) and overall scores on the Mental Health scale (P = .02) were significantly related to readmission within 6 months. CONCLUSIONS: Higher levels of depressive symptoms before coronary artery bypass grafting are related to higher hospital readmission rates 6 months after the procedure. Nurses can play a pivotal role in determining which patients require evaluation, educating patients, and initiating effective treatment, which may prevent readmission related to depressive symptoms.

Canadian-acquired hydatid disease: A case report.

Echinococcal cysts are unusual in Canada, and most cases seen are in immigrants. In northern Canadian communities, Echinococcus granulosis infection occasionally is acquired from dogs that feed on the entrails of caribou or moose. Seventeen patients with Canadian-acquired hydatid cysts were seen over an 11-year period. One challenging case is described in detail. An 18-year-old aboriginal woman presented with jaundice, pain, lower extremity edema and coagulopathy from a 26 cm echinococcal hepatic cyst. She was successfully treated with a combination of oral albendazole, percutaneous drainage and surgery. One-year follow-up showed no recurrence of disease. The management options for echinococcal cysts are extensively reviewed.

Paraoxonase polymorphisms, pesticide exposure and Parkinson's disease in a Caucasian population.

Parkinson's disease (PD) has been associated with exposure to pesticides and oxidative injury. The involvement of paraoxonase in both pesticide metabolism and lipid peroxidation suggests that it may play a role in the pathogenesis of PD. We examined the frequency of polymorphic alleles of the PON1 and PON2 genes in a sample of caucasian subjects with PD. The frequency distribution of these genotypes did not differ significantly between patients and controls, including those who had reported exposure to pesticides.