A particularly complex case of matricide by means of plastic bag suffocation: Case report

A rare case of homicide with plastic bag suffocation is presented in which forensic genetic investigations were carried out on the inner surface of a plastic bag placed over the head of an elderly woman, bedridden after a stroke. The results obtained suggested that she had been murdered and hinted at the perpetrator of the crime. In fact, it emerged that biological traces left by the victim matched those of her principal caregiver, her psychotic daughter, who later confessed to the crime. The old woman also had a son affected by a serious illness, whose genetic profile was found on the same bag. In a later interview, he stated that his sister had tried to kill him too, thus confirming the genetic findings and allowing the investigators to hypothesise that the daughter had used the same means to try to kill him. Based on these results, the usefulness of forensic genetic testing when investigating complex plastic bag suffocation deaths is highlighted. This peculiar case deserves interest, since no murder of this kind has ever been reported in the Italian forensic literature.

Overshoot during phenotypic switching of cancer cell populations

The dynamics of tumor cell populations is hotly debated: do populations derive hierarchically from a subpopulation of cancer stem cells (CSCs), or are stochastic transitions that mutate differentiated cancer cells to CSCs important? Here we argue that regulation must also be important. We sort human melanoma cells using three distinct cancer stem cell (CSC) markers - CXCR6, CD271 and ABCG2 - and observe that the fraction of non-CSC-marked cells first overshoots to a higher level and then returns to the level of unsorted cells. This clearly indicates that the CSC population is homeostatically regulated. Combining experimental measurements with theoretical modeling and numerical simulations, we show that the population dynamics of cancer cells is associated with a complex miRNA network regulating the Wnt and PI3K pathways. Hence phenotypic switching is not stochastic, but is tightly regulated by the balance between positive and negative cells in the population. Reducing the fraction of CSCs below a threshold triggers massive phenotypic switching, suggesting that a therapeutic strategy based on CSC eradication is unlikely to succeed.

Effect of whole body vibration frequency on neuromuscular activity in ACL-deficient and healthy males

Whole-body vibration (WBV) has been shown to enhance muscle activity via reflex pathways, thus having the potential to contrast muscle weakness in individuals with rupture of the anterior cruciate ligament (ACL). The present study aimed to compare the magnitude of neuromuscular activation during WBV over a frequency spectrum from 20 to 45 Hz between ACL-deficient and healthy individuals. Fifteen males aged 28±4 with ACL rupture and 15 age-matched healthy males were recruited. Root mean square (RMS) of the surface electromyogram from the vastus lateralis in both limbs was computed during WBV in a static half-squat position at 20, 25, 30, 35, 40 and 45 Hz, and normalized to the RMS while maintaining the half-squat position without vibration. The RMS of the vastus lateralis in the ACL-deficient limb was significantly greater than in the contralateral limb at 25, 30, 35 and 40 Hz (P<0.05) and in both limbs of the healthy participants (dominant limb at 25, 30, 35, 40 and 45 Hz, P<0.05; non dominant limb at 20, 25, 30, 35, 40 and 45 Hz, P<0.05). The greater neuromuscular activity in the injured limb compared to the uninjured limb of the ACL-deficient patients and to both limbs of the healthy participants during WBV might be due to either augmented excitatory or reduced inhibitory neural inflow to motoneurons of the vastus lateralis through the reflex pathways activated by vibratory stimuli. The study provides optimal WBV frequencies which might be used as reference values for ACL-deficient patients.

The molecular characterization of a depurinated trial DNA sample can be a model to understand the reliability of the results in forensic genetics

The role of DNA damage in PCR processivity/fidelity is a relevant topic in molecular investigation of aged/forensic samples. In order to reproduce one of the most common lesions occurring in postmortem tissues, a new protocol based on aqueous hydrolysis of the DNA was developed in vitro. Twenty-five forensic laboratories were then provided with 3.0 μg of a trial sample (TS) exhibiting, in mean, the loss of 1 base of 20, and a molecular weight below 300 bp. Each participating laboratory could freely choose any combination of methods, leading to the quantification and to the definition of the STR profile of the TS, through the documentation of each step of the analytical approaches selected. The results of the TS quantification by qPCR showed significant differences in the amount of DNA recorded by the participating laboratories using different commercial kits. These data show that only DNA quantification "relative" to the used kit (probe) is possible, being the "absolute" amount of DNA inversely related to the length of the target region (r(2) = 0.891). In addition, our results indicate that the absence of a shared stable and certified reference quantitative standard is also likely involved. STR profiling was carried out selecting five different commercial kits and amplifying the TS for a total number of 212 multiplex PCRs, thus representing an interesting overview of the different analytical protocols used by the participating laboratories. Nine laboratories decided to characterize the TS using a single kit, with a number of amplifications varying from 2 to 12, obtaining only partial STR profiles. Most of the participants determined partial or full profiles using a combination of two or more kits, and a number of amplifications varying from 2 to 27. The performance of each laboratory was described in terms of number of correctly characterized loci, dropped-out markers, unreliable genotypes, and incorrect results. The incidence of unreliable and incorrect genotypes was found to be higher for participants carrying out a limited number of amplifications, insufficient to define the correct genotypes from damaged DNA samples such as the TS. Finally, from a dataset containing about 4500 amplicons, the frequency of PCR artifacts (allele dropout, allele drop-in, and allelic imbalance) was calculated for each kit showing that the new chemistry of the kits is not able to overcome the concern of template-related factors. The results of this collaborative exercise emphasize the advantages of using a standardized degraded DNA sample in the definition of which analytical parameters are critical for the outcome of the STR profiles.

A global analysis of Y-chromosomal haplotype diversity for 23 STR loci

In a worldwide collaborative effort, 19,630 Y-chromosomes were sampled from 129 different populations in 51 countries. These chromosomes were typed for 23 short-tandem repeat (STR) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385ab, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, GATAH4, DYS481, DYS533, DYS549, DYS570, DYS576, and DYS643) and using the PowerPlex Y23 System (PPY23, Promega Corporation, Madison, WI). Locus-specific allelic spectra of these markers were determined and a consistently high level of allelic diversity was observed. A considerable number of null, duplicate and off-ladder alleles were revealed. Standard single-locus and haplotype-based parameters were calculated and compared between subsets of Y-STR markers established for forensic casework. The PPY23 marker set provides substantially stronger discriminatory power than other available kits but at the same time reveals the same general patterns of population structure as other marker sets. A strong correlation was observed between the number of Y-STRs included in a marker set and some of the forensic parameters under study. Interestingly a weak but consistent trend toward smaller genetic distances resulting from larger numbers of markers became apparent.

Bronchial selective ventilation in a wide tracheocutaneous fistula

We present the treatment and management of a wide tracheocutaneous fistula after tracheotomy correlated with excessive cuff pressure in a 36-year-old woman with cerebral palsy since infancy in which persistent type II respiratory failure required continuous ventilatory support. We discuss the surgical treatment adopted for the management of this particularly wide lesion. At the end of surgery, mechanical ventilation through a tracheal cannula was hindered by the reduced length of the residual trachea below the tracheotomy. The need to guarantee mechanical ventilation to the patient led to the implementation of a cuff securing system in the two main bronchi. We describe the approach that may be attempted under extreme conditions, when traditional ventilation methods cannot be applied for anatomical reasons.

Melanoma contains CD133 and ABCG2 positive cells with enhanced tumourigenic potential

The failure to eradicate most cancers and in particular melanoma may be as fundamental as a misidentification of the target. The identification of cancer stem/initiating cells within the tumour population with a crucial role for tumour formation may open new pharmacological perspectives. Our data show three main novelties for human melanoma: firstly, melanoma biopsy contains a subset of cells expressing CD133 (CD133+) and the latter is able to develop a Mart-1 positive tumour in NOD-SCID mice. Secondly, the WM115, a human melanoma cell line, has been found to express both CD133 and ABCG2 markers. This cell line grows as floating spheroids, expresses typical progenitors and mature neuronal/oligodendrocyte markers and is able to transdifferentiate into astrocytes or mesenchymal lineages under specific growth conditions. As in xenografts generated with CD133+ biopsy melanoma cells, those produced by the cell line displayed lower levels of CD133 and ABCG2. Thirdly, the WM115 cells express the most important angiogenic and lymphoangiogenic factors such as notch 4, prox1 and podoplanin which can cooperate in the development of the tumourigenic capability of melanoma in vivo. Therefore, in this study, we demonstrate the presence of stem/initiating subsets in melanoma both in biopsy and in an established melanoma cell line grown in vitro and in xenografts. Interestingly, considering that melanoma gives metastasis primarily through lymphatic vessels, herein, we demonstrated that a melanoma cell line expresses typical lymphoangiogenic factors.

Melanoma contains CD133 and ABCG2 positive cells with enhanced tumourigenic potential

The failure to eradicate most cancers and in particular melanoma may be as fundamental as a misidentification of the target. The identification of cancer stem/initiating cells within the tumour population with a crucial role for tumour formation may open new pharmacological perspectives. Our data show three main novelties for human melanoma: firstly, melanoma biopsy contains a subset of cells expressing CD133 (CD133+) and the latter is able to develop a Mart-1 positive tumour in NOD-SCID mice. Secondly, the WM115, a human melanoma cell line, has been found to express both CD133 and ABCG2 markers. This cell line grows as floating spheroids, expresses typical progenitors and mature neuronal/oligodendrocyte markers and is able to transdifferentiate into astrocytes or mesenchymal lineages under specific growth conditions. As in xenografts generated with CD133+ biopsy melanoma cells, those produced by the cell line displayed lower levels of CD133 and ABCG2. Thirdly, the WM115 cells express the most important angiogenic and lymphoangiogenic factors such as notch 4, prox1 and podoplanin which can cooperate in the development of the tumourigenic capability of melanoma in vivo. Therefore, in this study, we demonstrate the presence of stem/initiating subsets in melanoma both in biopsy and in an established melanoma cell line grown in vitro and in xenografts. Interestingly, considering that melanoma gives metastasis primarily through lymphatic vessels, herein, we demonstrated that a melanoma cell line expresses typical lymphoangiogenic factors.

Validation of a large Italian Database of 15 STR loci

Results from a collaborative exercise with proficiency testing conducted by 20 Italian laboratories on the 15 loci included in the Identifiler kit were analyzed by allele sharing methods and by standard population genetics tests. The validated database, including about 1500 subjects, was merged with that of a previous exercise conducted on nine loci, and the resulting allele frequencies, subdivided by Italian region, were published on-line.

International collaboration in mass disasters involving foreign nationals within the EU: medico-legal investigation of Finnish victims of the Milan Linate airport SAS SK 686 aircraft accident on 8 October 2001

Identification of and investigation into the cause of death of foreign nationals in mass disasters are generally conducted according to the jurisdiction of the country in which the disaster occurs. However, such identification can be achieved only through co-operation with the authorities of the victims' countries of residence. On October 8th 2001 at Linate airport in Milan, Italy, an MD87 SAS airplane with 110 crew members and passengers on board collided on the ground with a Cessna Citation II jet with 2 pilots and 2 passengers. The plane then caught fire after having crashed into an airport baggage hangar causing the death of 4 other victims among the groundstaff. The accident claimed a total of 118 victims of 9 nationalities. Based on our experience from investigation of the Finnish victims, we explore how current national legislations of the EU member states and varying compliance with existing recommendations may influence the medico-legal investigation of a mass disaster. Legislative measures and further harmonisation of medico-legal procedures in connection with mass disasters within the EU are needed.

Allele sharing in first-degree and unrelated pairs of individuals in the Ge F I AmpFlSTR Profiler Plus database

Eleven Italian forensic laboratories participated in a population study based on the AB Profiler Plus loci with proficiency testing. The validated database, including 1340 individuals, is available on-line. Tests for Hardy-Weinberg equilibrium, gametic unbalance, and heterogeneity of gene frequency were generally not significant. Gene frequencies at each locus were consistent with those of two previously published Italian studies, but different from a third. Individuals of each subsample were paired, and the total number of alleles shared across the nine loci was determined in each pair. The analysis was replicated over the total sample. In addition, two samples of mother-child pairs (N=315) and full-sib pairs (N=91) were subjected to allele sharing analysis. The resulting distributions were sufficiently distinct from the sample of unrelated pairs as to be of practical usefulness.