Individualization of pubic hair bacterial communities and the effects of storage time and temperature

A potential application of microbial genetics in forensic science is detection of transfer of the pubic hair microbiome between individuals during sexual intercourse using high-throughput sequencing. In addition to the primary need to show whether the pubic hair microbiome is individualizing, one aspect that must be addressed before using the microbiome in criminal casework involves the impact of storage on the microbiome of samples recovered for forensic testing. To test the effects of short-term storage, pubic hair samples were collected from volunteers and stored at room temperature (∼20 °C), refrigerated (4 °C), and frozen (–20 °C) for 1 week, 2 weeks, 4 weeks, and 6 weeks along with a baseline sample. Individual microbial profiles (R² = 0.69) and gender (R² = 0.17) were the greatest sources of variation between samples. Because of this variation, individual and gender could be predicted using Random Forests supervised classification in this sample set with an overall error rate of 2.7% ±  5.8% and 1.7% ± 5.2%, respectively. There was no statistically significant difference attributable to time of sampling or temperature of storage within individuals. Further work on larger sample sets will quantify the temporal consistency of individual profiles and define whether it is plausible to detect transfer between sexual partners. For short-term storage (≤6 weeks), recovery of the microbiome was not affected significantly by either storage time or temperature, suggesting that investigators and crime laboratories can use existing evidence storage methods.     

Application of Lithium Assay kit LS for quantification of lithium in whole blood and urine

A commercially available kit for the quantitation of lithium, the Lithium Assay kit LS, was originally developed to measure lithium in serum or plasma using a conventional microplate reader. We investigated whether use of the kit could be extended to quantify lithium in whole blood and urine samples collected at autopsy. The calibration curve for whole blood showed good linearity ranging from 0.5 to 20 µg/mL with a coefficient of determination of 0.998 when samples were pretreated with methanol followed by acetonitrile. Moreover, for urine, we obtained excellent linearity with a coefficient of determination of 0.999 without any pretreatment. The accuracies and precisions were 106.3–174.7% and 1.9–18.1% for whole blood and 83.3–118.8% and 5.7–33.8% for urine. The values in the lower concentration range (0.5–1 µg/mL) were not satisfactory, whereas those in the higher range (2–20 µg/mL) were acceptable. The Lithium Assay kit LS was successfully applied to the measurement of lithium in whole blood and urine samples collected at autopsies. This method appears to be useful for forensic toxicological investigations because of its simplicity and speed.     

Determining the effect of water temperature on the T1 and T2 relaxation times of the lung tissue at 9.4 T MRI: A drowning mouse model

Japanese individuals have a unique culture of soaking in a bathtub, and forensic pathologists have experienced fatal cases due to drowning. However, T1 and T2 relaxation times of a drowning lung are poorly documented.In the present study, we investigated the relationship between drowning water temperature and T1 and T2 relaxation times of drowning lung tissues at 9.4 T MRI (Bruker, BioSpec94/20USR). The mice used as animal drowning models were directly submerged in freshwater. Water temperature was set to 8 °C–10 °C (cold), 20 °C–22 °C (normal), 30 °C, and 45 °C. The regions of interest (ROIs) on the axial section of the third slice were set at the central and peripheral areas of each—the left and the right—lung. T1 relaxation times measured immediately after death differed by the presence or absence of soaking water, except in case of cold water temperature. In the drowning groups, T1 relaxation time showed a linear dependency on water temperature. By contrast, T2 relaxation time was almost constant regardless of the presence of drowning under the same temperature condition; when compared in the lung areas of the same individuals, the times were uniformly reduced in drowning models. To minimize the effects of hypostasis and decomposition, we performed measurements immediately after death and were able to determine the noticeable difference in drowning water temperature. These results may be useful for qualitative assessments of a drowning lung and may serve as a basis when imaging the human body during forensic autopsy cases.     

Streptococcal toxic shock syndrome with fatal outcome: Report on four forensic autopsy cases

Streptococcal toxic shock syndrome (STSS) is a severe infection most commonly caused by group A streptococcus. It is clinically characterized by rapidly progressive multiple organ failure and septic shock. This report presents four fatal cases associated with STSS. In two cases (cases 2 and 3), the portals of entry may be ulcer and mucosa at the surgical site; the initial symptoms in these cases included fever. In the other cases, the portal of entry was unknown; the initial symptom was pain. In two cases (cases 1 and 3), malpractice was suspected before autopsy. At autopsy, blood culture was positive for group A streptococcus in all of the present cases. Although C-reactive protein levels were increased, procalcitonin levels were not markedly elevated. This is the first report of autopsy cases associated with STSS in which postmortem computed tomography was performed; the swelling of muscles and increased concentrations of peripheral subcutaneous tissue without gas may be characteristic findings. Histology revealed extensive bacterial colonies and necrosis with mild neutrophilic reaction in two cases (cases 3 and 4), and hemophagocytosis in two cases (cases 1 and 4). It is essential to perform appropriate examinations and make a proper diagnosis because STSS still has a high fatality rate and medical malpractice is often suspected. In addition, it is important to evaluate STSS again for the reduction of the fatal cases associated with STSS.     

Mutation analysis for 25 Y-STR markers in Japanese population

In this study, we analyzed DNA samples from 213 Japanese father son pairs with 25 Y-chromosome short tandem repeat (Y-STR) (DYS576, DYS389I, DYS635, DYS389II, DYS627, DYS460, DYS458, DYS19, YGATAH4, DYS448, DYS391, DYS456, DYS390, DYS438, DYS392, DYS518, DYS570, DYS437, DYS385, DYS449, DYS393, DYS439, DYS481, DYF387S1, and DYS533) markers using the Yfiler™ Plus PCR amplification kit. We calculated Y-STR mutation rates for each locus to evaluate the efficacy of the 25 Y-STR markers for paternity testing and forensic identification using samples from male relatives. Six rapidly mutating Y-STR markers (DYS576, DYS627, DYS518, DYS570, DYS449 and DYF387S1), previously reported to have high mutation rates (>1.0 × 10⁻²), are included in the 25 Y-STR markers, but our findings revealed that the mutation rates for all Y-STR markers except for DYS576 and DYS458 were lower than 1.0 × 10⁻². Therefore, the use of these 25 Y-STR markers may be useful for forensic identification in the Japanese population.     

Kinetics and distribution of benzalkonium compounds with different alkyl chain length following intravenous administration in rats

Benzalkonium chloride is widely used in disinfectants. Several toxicological and fatal cases have been reported; however, little is known about its kinetics and distribution. We investigated the kinetic characteristics and distribution of benzalkonium cation (BZK) based on the length of the alkyl chains C12, C14, and C16. Rats were treated intravenously with BZK solution (dose, 13.9 mg/kg) containing equal amounts of the three homologues. Kinetic parameters in the blood were assessed, and BZK distribution in the blood and tissues was examined both in rapid intravenous (IV) and drip intravenous (DIV) administrations. BZK concentrations were analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). BZK with longer alkyl chains showed lower elimination tendencies and remained in the blood for a longer duration. Concentrations of BZK were higher in the heart, lung, spleen, and kidney than those in the blood, and lower in the brain and fat. In both the IV and DIV groups, the lung, liver, spleen, and fat samples showed higher concentrations of the longer alkyl chains (BZK-C12 < -C14 < -C16), and the opposite trend was observed in the kidney (BZK-C16 < -C14 < -C12). Only the heart and muscle samples displayed the homologues in ratios comparable to the original administered solutions. Differences between IV and DIV groups could be identified by comparing concentrations of BZK homologues in the heart, lung, spleen, and kidney samples. We found that the kinetics and distribution of BZK were influenced by the alkyl chain length, and analysing each BZK homologues in blood and tissue samples may provide useful information.     

FST estimates of 94 populations in China based on STR markers

The proper assessment of DNA evidence in cases of personal identification is a recurring theme in forensics. It is common practice to evaluate the strength of DNA evidence using the likelihood ratio (LR). The accurate use of population allele frequencies is a crucial problem in LR calculation. Allele frequency differences among different populations could be estimated by the F_ST values. Thus, F_ST would also affect LR values by correcting the allele frequencies. In this study, Chinese population allele frequency data were selected from population reports published in Chinese and English journals. The population-specific F_ST values of each population, the overall F_ST values of each province, each region, and the whole country, and the locus-specific F_ST values of different loci were calculated. The LRs using different allele frequencies and different F_ST values were compared based on the combination of simulated genotypes. As a result, the F_ST values of 94 populations, 19 provinces, 7 regions, and the whole country were obtained. The LR was overestimated using allele frequencies of the combined population containing multiple populations rather than using allele frequencies of a population, and the LRs after F_ST correction were lower than those without correction. Conclusively, the correction in conjunction with corresponding F_ST values can make the LRs more accurate and reasonable.     

STRait Razor: A length-based forensic STR allele-calling tool for use with second generation sequencing data

Recent studies have demonstrated the capability of second generation sequencing (SGS) to provide coverage of short tandem repeats (STRs) found within the human genome. However, there are relatively few bioinformatic software packages capable of detecting these markers in the raw sequence data. The extant STR-calling tools are sophisticated, but are not always applicable to the analysis of the STR loci commonly used in forensic analyses. STRait Razor is a newly developed Perl-based software tool that runs on the Linux/Unix operating system and is designed to detect forensically-relevant STR alleles in FASTQ sequence data, based on allelic length. It is capable of analyzing STR loci with repeat motifs ranging from simple to complex without the need for extensive allelic sequence data. STRait Razor is designed to interpret both single-end and paired-end data and relies on intelligent parallel processing to reduce analysis time. Users are presented with a number of customization options, including variable mismatch detection parameters, as well as the ability to easily allow for the detection of alleles at new loci. In its current state, the software detects alleles for 44 autosomal and Y-chromosome STR loci. The study described herein demonstrates that STRait Razor is capable of detecting STR alleles in data generated by multiple library preparation methods and two Illumina^® sequencing instruments, with 100% concordance. The data also reveal noteworthy concepts related to the effect of different preparation chemistries and sequencing parameters on the bioinformatic detection of STR alleles.     

The Role of HINT1 in Methamphetamine-Induced Conditioned Place Preference

Drug addiction is a chronically relapsing disorder in humans; yet, the underlying mechanism remained unclear. Recent studies suggested that the histidine triad nucleotide binding protein 1 (HINT1) may play significant roles in diverse neuropsychiatric diseases including drug addiction. In our present study, we used different batches of mice to establish the different stages of methamphetamine (METH)-induced conditioned place preference (CPP) to explore the dynamic changes throughout the process of addiction in different brain regions, including prefrontal cortex (PFC), nucleus accumbens (NAc), corpus striatum (CPu), and hippocampus (Hip). We found that in NAc of the METH group mice, the HINT1 expression level initially increased after acquisition phases, and then dropped to the normal level after extinction phase, and again increased after reinstatement phase. However, there was no statistical difference in the HINT1 expression level in other three encephalic regions (PFC, CPu, and Hip). Therefore, the HINT1 protein, particularly in the NAc, plays a vital role in the METH-induced CPP. However, the precise mechanisms will require further investigation.     

盐酸氯丙嗪急性中毒致死小鼠血浆中差异代谢物的筛选

目的 通过对盐酸氯丙嗪急性中毒小鼠血浆内代谢物进行非靶向代谢组学分析,筛选出与盐酸氯丙嗪急性中毒致死相关的差异代谢物.方法 随机选取24只ICR小鼠并将其随机分为盐水对照组、盐酸氯丙嗪试验组,每组 12只.应用超高效液相色谱-高分辨质谱(ultra-high performance liquid chromatogra...