Comparison and interpretation of impressed marks left by a firearm on cartridge cases - Towards an operational implementation of a likelihood ratio based technique.

Firearm examination is subject to increased scrutiny regarding its foundational validity and inherent subjective nature. The increased use of automatic comparison systems may help to reduce subjectivity. In this paper, we present the performance and limits of an automatic comparison system that assigns a weight to the forensic findings for the comparisons between firing pin marks, breechface marks, or a combination of the two. This weight is expressed by a likelihood ratio (LR) based on 3D topographical measurements coupled with a bi-dimensional statistical model. As the performance of such systems may depend on the reference databases used to inform the model, we investigated the impact of the brand of ammunition and the number of samples. We show that reference databases used to calculate LRs should ideally consist of the same type of ammunition as is seen in the case under investigation and that 7 specimens fired by the same firearm are enough to obtain rates of misleading evidence of a similar magnitude compared to those obtained when far more specimens (60) are used. Additionally, the automatic system was used to assess the outcomes of 7 cases with known same-source or different-source ground truths. These cases were also examined by 8 qualified firearm examiners. In all cases, the experts' appraisals were in line with the ground truth. The automatic system showed some limitations in cases were the data were not sufficient to calculate a robust LR, but also that it can assist and enhance the examiners in their decision process.

Interleukin-32 upregulates the expression of ABCA1 and ABCG1 resulting in reduced intracellular lipid concentrations in primary human hepatocytes.

BACKGROUND AND AIMS: The role of interleukin (IL-)32 in inflammatory conditions is well-established, however, the mechanism behind its role in atherosclerosis remains unexplained. Our group reported a promoter single nucleotide polymorphism in IL-32 associated with higher high-density lipoprotein (HDL) concentrations. We hypothesize that endogenous IL-32 in liver cells, a human monocytic cell line and carotid plaque tissue, can affect atherosclerosis by regulating (HDL) cholesterol homeostasis via expression of cholesterol transporters/mediators. METHODS: Human primary liver cells were stimulated with recombinant human (rh)TNFα and poly I:C to study the expression of IL-32 and mediators in cholesterol pathways. Additionally, IL-32 was overexpressed in HepG2 cells and overexpressed and silenced in THP-1 cells to study the direct effect of IL-32 on cholesterol transporters expression and function. RESULTS: Stimulation of human primary liver cells resulted in induction of IL-32α, IL-32ß and IL-32γ mRNA expression (p < 0.01). A strong correlation between the expression of IL-32γ and ABCA1, ABCG1, LXRα and apoA1 was observed (p < 0.01), and intracellular lipid concentrations were reduced in the presence of endogenous IL-32 (p < 0.05). Finally, IL32γ and ABCA1 mRNA expression was upregulated in carotid plaque tissue and when IL-32 was silenced in THP-1 cells, mRNA expression of ABCA1 was strongly reduced. CONCLUSIONS: Regulation of IL-32 in human primary liver cells, HepG2 and THP-1 cells strongly influences the mRNA expression of ABCA1, ABCG1, LXRα and apoA1 and affects intracellular lipid concentrations in the presence of endogenous IL-32. These data, for the first time, show an important role for IL32 in cholesterol homeostasis.

Objective Evaluation of Subclass Characteristics on Breech Face Marks.

Subclass characteristics can be found on the breech face marks left on spent cartridge cases. Even if they are assumed to be rare and their reported number is small, they can potentially lead to false associations. Subclass characteristics have been studied empirically allowing examiners to recognize them and to understand in which conditions they are produced. Until now, however, their influence on the identification process has not been studied from a probabilistic point of view. In this study, we aim at measuring the effect of these features on the strength of association derived from examinations involving subclass characteristics. The study takes advantage of a 3D automatic comparison system allowing the calculation of likelihood ratios (LRs). The similarities between cartridge case specimens fired by thirteen S&W .40S&W Sigma pistols are quantified, and their respective LRs are computed. The results show that the influence of subclass characteristics on the LRs is limited, even when these features are prevalent among the potential sources considered in a case. We show that the proportion of firearms sharing subclass characteristics should be larger than 40% of the pool of potential firearms for the effect to be significant.

Interaction of bullets with intermediate targets: material transfer and damage.

In complex shooting incidents, it is not always clear which bullet hit or eventually killed the victim and who fired it. The examination of traces of foreign material embedded in or adhered to bullets provides critical information in the trajectory reconstruction of spent bullets. Such a reconstruction can have considerable legal implications because it can prove that it was not someone's intention to kill. However, the microtraces that remain on spent bullets are often ignored. Microtraces on bullets, around bullet-holes and on ricochet marks were investigated using SEM/EDX for two different types of bullets: a relatively hard, full metal jacket (FMJ) bullet and a relatively soft, lead round-nose (LRN) bullet. A total of 179 bullets were fired into intermediate targets, sheets of 5 different materials (MDF, greenboard, gypsum fibreboard, glass and steel), at approximate incident angles of 90°, 10° and 5°. Of the 144 bullets fired at incident angles of 90°, 130 bullets perforated one of the materials, and 14 bullets perforated two of the materials. The 35 bullets fired at incident angles of 10° and 5° ricocheted off the intermediate targets, producing ricochet marks. In the majority of cases, traces from the target materials were found on the bullet, both after perforation and ricochet. The only exceptions were (1) the perforation of 9-mm sheets of MDF by FMJ bullets and (2) ricochet off glass when the glass did not break. Steel targets transfer small, but still detectable traces of iron to the bullet. The order in which targets are hit was reflected in the traces found on the bullets, i.e., materials from a secondary target were deposited on top of deposits from the primary target. This result implies that it is possible to determine the order of impact from the stratification of the material analysed. Traces from the bullets were found around all the bullet holes. Wipe-off from lead bullets is sometimes visible by the naked eye. Ricocheting bullets produce remarkable traces on glass. The combination of sliding and flattening action leaves a trace of the bullet's surface material in the form of tiny droplets and other evidence of liquid formation. In general, softer LRN bullets are more susceptible to the transfer of material than harder FMJ bullets. For perforation, trace materials are preferentially deposited in a ring-shaped area around the (flattened or unflattened) nose of the bullet.

A cluster-randomized trial of mass drug administration with a gametocytocidal drug combination to interrupt malaria transmission in a low endemic area in Tanzania.

BACKGROUND: Effective mass drug administration (MDA) with anti-malarial drugs can clear the human infectious reservoir for malaria and thereby interrupt malaria transmission. The likelihood of success of MDA depends on the intensity and seasonality of malaria transmission, the efficacy of the intervention in rapidly clearing all malaria parasite stages and the degree to which symptomatic and asymptomatic parasite carriers participate in the intervention. The impact of MDA with the gametocytocidal drug combination sulphadoxine-pyrimethamine (SP) plus artesunate (AS) plus primaquine (PQ, single dose 0.75 mg/kg) on malaria transmission was determined in an area of very low and seasonal malaria transmission in northern Tanzania. METHODS: In a cluster-randomized trial in four villages in Lower Moshi, Tanzania, eight clusters (1,110 individuals; cluster size 47- 209) were randomized to observed treatment with SP+AS+PQ and eight clusters (2,347 individuals, cluster size 55- 737) to treatment with placebo over three days. Intervention and control clusters were 1 km apart; households that were located between clusters were treated as buffer zones where all individuals received SP+AS+PQ but were not selected for the evaluation. Passive case detection was done for the entire cohort and active case detection in 149 children aged 1-10 year from the intervention arm and 143 from the control arm. Four cross-sectional surveys assessed parasite carriage by microscopy and molecular methods during a five-month follow-up period. RESULTS: The coverage rate in the intervention arm was 93.0% (1,117/1,201). Parasite prevalence by molecular detection methods was 2.2-2.7% prior to the intervention and undetectable during follow-up in both the control and intervention clusters. None of the slides collected during cross-sectional surveys had microscopically detectable parasite densities. Three clinical malaria episodes occurred in the intervention (n = 1) and control clusters (n = 2). CONCLUSIONS: This study illustrates the possibility to achieve high coverage with a three-day intervention but also the difficulty in defining suitable outcome measures to evaluate interventions in areas of very low malaria transmission intensity. The decline in transmission intensity prior to the intervention made it impossible to assess the impact of MDA in the chosen study setting. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00509015.

Contribution of different local vascular responses to mid-gestational vasodilation.

OBJECTIVE: At-term pregnancy-induced vasodilation is the resultant of endothelium-dependent vasodilation, decreased myogenic reactivity, increased compliance, and reduced sensitivity to vasoconstrictor agents. We hypothesized that these vascular changes are already present at mid-gestation. STUDY DESIGN: In 20 mid-pregnant and 20 nonpregnant Wistar Hannover rats, we measured vascular responses of isolated mesenteric arteries and kidney. RESULTS: In the pregnant rats compared with the nonpregnant rats, mesenteric flow-mediated vasodilation and renal perfusion flow increased 1.52-fold (from 47±5 to 31±4 µL/min) and 1.13-fold (from 12.8±0.1 to 14.4±0.1 mL/min), respectively. Nitric oxide inhibition reduced mesenteric flow-mediated vasodilation to a similar extent in the pregnant and nonpregnant rats; it completely blocked the pregnancy-induced increase in renal perfusion flow. Pregnancy did not change mesenteric artery sensitivity to phenylephrine, myogenic reactivity, nor vascular compliance. CONCLUSION: At mid-gestation, alterations in rat mesenteric vascular tone depend primarily on flow-mediated endothelium-dependent changes and not on changes in α-adrenergic vasoconstrictor sensitivity, myogenic reactivity, or vascular compliance.

Does suggestive information cause a confirmation bias in bullet comparisons?

Several researchers have argued that the confirmation bias, the tendency to selectively gather and process information such that it fits existing beliefs, is a main threat to objective forensic examinations. The goal of the present study was to empirically investigate whether examiners making bullet comparisons are indeed vulnerable to this bias. In the first experiment, six qualified examiners evaluated 6 sets of bullets that were presented to them twice. In the neutral task condition it was mentioned in the case description that there were two perpetrators and two crime scenes, whereas in the potentially biasing task condition it was mentioned that there was only one perpetrator and one crime scene. The results showed no effect of biased information on the decision outcome. An exploratory analysis revealed rather large individual differences in two cases. In a second study we compared the conclusions of first and second examiners of actual cases that were conducted in the period between 1997 and 2006. As the second examiner mostly has no context information it may be expected that the conclusion of the first examiner should be more extreme when he or she would have become prey to a confirmation bias. The results indicate an effect in the opposite direction: the first examiner gave less extreme ratings than the second one. In all, our results indicate that examiners were not affected by biased information the case description.

Quantitative determination of Plasmodium vivax gametocytes by real-time quantitative nucleic acid sequence-based amplification in clinical samples.

Microscopic detection of Plasmodium vivax gametocytes, the sexual life stage of this malaria parasite, is insensitive because P. vivax parasitaemia is low. To detect and quantify gametocytes a more sensitive, quantitative real-time Pvs25-QT-NASBA based on Pvs25 mRNA was developed and tested in two clinical sample sets from three different continents. Pvs25-QT-NASBA is highly reproducible with low inter-assay variation and reaches sensitivity approximately 800 times higher than conventional microscopic gametocyte detection. Specificity was tested in 104 samples from P. vivax-, P. falciparum-, P. malariae-, and P. ovale-infected patients. All non-vivax samples were negative in the Pvs25-QT-NASBA; out of 74 PvS18-QT-NASBA positive samples 69% were positive in the Pvs25-QT-NASBA. In a second set of 136 P. vivax microscopically confirmed samples, gametocyte prevalence was 8%, whereas in contrast 66% were positive by Pvs25-QT-NASBA. The data suggest that the human P. vivax gametocyte reservoir is much larger when assessed by Pvs25-QT-NASBA than by microscopy.

Safety and immunogenicity of a recombinant Plasmodium falciparum AMA1 malaria vaccine adjuvanted with Alhydrogel, Montanide ISA 720 or AS02.

BACKGROUND: Plasmodium falciparum Apical Membrane Antigen 1 (PfAMA1) is a candidate vaccine antigen expressed by merozoites and sporozoites. It plays a key role in red blood cell and hepatocyte invasion that can be blocked by antibodies. METHODOLOGY/PRINCIPAL FINDINGS: We assessed the safety and immunogenicity of recombinant PfAMA1 in a dose-escalating, phase Ia trial. PfAMA1 FVO strain, produced in Pichia pastoris, was reconstituted at 10 microg and 50 microg doses with three different adjuvants, Alhydrogel, Montanide ISA720 and AS02 Adjuvant System. Six randomised groups of healthy male volunteers, 8-10 volunteers each, were scheduled to receive three immunisations at 4-week intervals. Safety and immunogenicity data were collected over one year. Transient pain was the predominant injection site reaction (80-100%). Induration occurred in the Montanide 50 microg group, resulting in a sterile abscess in two volunteers. Systemic adverse events occurred mainly in the AS02 groups lasting for 1-2 days. Erythema was observed in 22% of Montanide and 59% of AS02 group volunteers. After the second dose, six volunteers in the AS02 group and one in the Montanide group who reported grade 3 erythema (>50 mm) were withdrawn as they met the stopping criteria. All adverse events resolved. There were no vaccine-related serious adverse events. Humoral responses were highest in the AS02 groups. Antibodies showed activity in an in vitro growth inhibition assay up to 80%. Upon stimulation with the vaccine, peripheral mononuclear cells from all groups proliferated and secreted IFNgamma and IL-5 cytokines. CONCLUSIONS/SIGNIFICANCE: All formulations showed distinct reactogenicity profiles. All formulations with PfAMA1 were immunogenic and induced functional antibodies. TRIAL REGISTRATION: (Clinicaltrials.gov) NCT00730782.

Experimental evaluation of the impact of seating depth variations on observed marks on primers.

Although the examination of bullet and primer striae patterns is still a very important task in forensic ballistics, a fundamental explanation or theoretical model for reasoning about the (ir)reproducibility of the observed marks is still non-existing. More specifically, it is still unclear which ammunition production or firing condition parameters may play an important role in the striae and marks formation process. From a practical point of view this situation is unfortunate because a proper knowledge of these parameters and conditions could help underpin and explain certain differences found in actual casework investigations. Additionally, a proper understanding of these issues could allow examiners to select or develop a near-optimal test firing procedure by using more detailed and controlled variations of certain intra- and/or inter-ammunition parameters than the ones that are in use today. In this paper, we discuss the results of an experiment aimed at evaluating the impact of primer seating depth variations on observed primer striae and other marks. First, three sets of cartridge cases with different seating depth intervals were selected. Second, each of these sets were fired consecutively using a selected pistol. Finally, the cartridge cases were examined using both traditional optical microscopes and three-dimensional (3D) profilometer techniques. The results reported in this paper show that in our experiments no important impact of the initial primer seating depth on the observed primer striae patterns could be found, but that the firing pin impression does seem to change if the initial seating depth is larger than a certain threshold.

Real-time nucleic acid sequence-based amplification is more convenient than real-time PCR for quantification of Plasmodium falciparum.

Determination of the number of malaria parasites by routine or even expert microscopy is not always sufficiently sensitive for detailed quantitative studies on the population dynamics of Plasmodium falciparum, such as intervention or vaccine trials. To circumvent this problem, two more sensitive assays, real-time quantitative nucleic acid sequence-based amplification (QT-NASBA) and real-time quantitative PCR (QT-PCR) were compared for quantification of P. falciparum parasites. QT-NASBA was adapted to molecular beacon real-time detection technology, which enables a reduction of the time of analysis and of contamination risk while retaining the specificity and sensitivity of the original assay. Both QT-NASBA and QT-PCR have a sensitivity of 20 parasites/ml of blood, but QT-PCR requires a complicated DNA extraction procedure and the use of 500 microl of venous blood to achieve this sensitivity, compared to 50 microl of finger prick blood for real-time QT-NASBA. Both techniques show a significant correlation to microscopic parasite counts, and the quantification results of the two real-time assays are significantly correlated for in vitro as well as in vivo samples. However, in comparison to real-time QT-PCR, the results of real-time QT-NASBA can be obtained 12 h earlier, with relatively easy RNA extraction and use of finger prick blood samples. The prospective development of multiplex QT-NASBA for detection of various P. falciparum developmental stages increases the value of QT-NASBA for malaria studies. Therefore, for studies requiring sensitive and accurate detection of P. falciparum parasites in large numbers of samples, the use of real-time QT-NASBA is preferred over that of real-time QT-PCR.

Plasmodium falciparum associated with severe childhood malaria preferentially expresses PfEMP1 encoded by group A var genes.

Parasite-encoded variant surface antigens (VSAs) like the var gene-encoded Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) family are responsible for antigenic variation and infected red blood cell (RBC) cytoadhesion in P. falciparum malaria. Parasites causing severe malaria in nonimmune patients tend to express a restricted subset of VSA (VSA(SM)) that differs from VSA associated with uncomplicated malaria and asymptomatic infection (VSA(UM)). We compared var gene transcription in unselected P. falciparum clone 3D7 expressing VSA(UM) to in vitro-selected sublines expressing VSA(SM) to identify PfEMP1 responsible for the VSA(SM) phenotype. Expression of VSA(SM) was accompanied by up-regulation of Group A var genes. The most prominently up-regulated Group A gene (PFD1235w/MAL7P1.1) was translated into a protein expressed on the infected RBC surface. The proteins encoded by Group A var genes, such as PFD1235w/MAL7P1.1, appear to be involved in the pathogenesis of severe disease and are thus attractive candidates for a vaccine against life-threatening P. falciparum malaria.

Pharmacokinetics and immunological aspects of a phase Ib study with intratumoral administration of recombinant human interleukin-12 in patients with head and neck squamous cell carcinoma: a decrease of T-bet in peripheral blood mononuclear cells.

The aim of this study was to evaluate the tolerability of intratumoral administered recombinant human interleukin-12 (rhIL-12) in patients with head and neck squamous cell carcinoma. Six patients were treated once a week at two dose levels of 100 or 300 ng/kg, respectively, up to 24 weeks. The primary end point was to assess the toxicity and safety of intratumoral injected rhIL-12 in head and neck squamous cell carcinoma patients; the pharmacokinetics and pharmacodynamics of rhIL-12 and any evidence of antitumor effect were also determined. Toxicity was mild, with prolonged grade 4 lymphopenia observed in only one patient. No dose-limiting toxicities occurred. In all six patients, the rhIL-12 was detectable in plasma within 30 min. Significant reductions in absolute number of peripheral blood lymphocytes and all lymphocyte subsets, especially cytotoxic T cells and natural killer cells, were observed that were maximal between 12 and 24 h. Maximal plasma concentrations of IFN-gamma and IL-10 were detected after 12 h. A real-time semiquantitative PCR analysis in peripheral blood mononuclear cells showed a mean increase of mRNA encoding IFN-gamma of 2.2 times relative to the pretreatment sample. An unexpected, significant decrease of 80% in T-bet mRNA, a T-helper 1 transcription factor, was detected after 12 h, with normalization after 48-72 h. No complete or partial responses were observed. In one patient, a 40% regression of a tumor lesion was noted. In conclusion, rhIL-12 at these dose levels and schedule was well tolerated and resulted in measurable immunological responses.