Therapy-Related Acute Myeloid Leukemia Diagnosed at Postmortem in a Long-term Survivor of Advanced Hepatocellular Carcinoma

Acute myeloid leukemia (AML) is a common hematologic malignancy with high mortality and a short survival period in adults. About 10% of these cases, called therapy-related AML, are reported to be the consequence of chemotherapy or radiotherapy of previous malignancy. In a clinical setting, this is usually diagnosed by peripheral blood smear or bone marrow biopsy by assessing the proportion of blasts. However, postmortem blood samples are not suitable for smear analysis because of hemolysis. Therefore, ancillary tests for identifying leukemic infiltration or related molecular change can provide an alternative diagnostic clue for AML. The deceased had been treated for 3 years for a combined type of hepatocellular carcinoma with multiple pulmonary metastases. Treatments included the resections of primary and metastatic tumors, chemotherapy, and radiotherapy, which prevented further progression of his cancer. One year after the last treatment, he suddenly collapsed without any specific symptoms and shortly died. The microscopic examination of the autopsy samples revealed extensive extramedullary infiltration of leukemia, which was confirmed as an AML by a series of ancillary immunohistochemical staining. This case illustrates both the importance of careful hematologic observation in cancer survivors and the necessity of a detailed medical diagnosis in a medicolegal autopsy.

A Response Surface Methodology (RSM) Approach for Optimizing the Attenuation of Human IgE-Reactivity to β-Lactoglobulin (β-Lg) by Hydrostatic High Pressure Processing

The response surface methodology (RSM) and central composite design (CCD) technique were used to optimize the three key process parameters (i.e., pressure, temperature and holding time) of the high-hydrostatic-pressure (HHP) processing either standalone or combined with moderate thermal processing to modulate molecular structures of β-lactoglobulin (β-Lg) and α-lactalbumin (α-La) with reduced human IgE-reactivity. The RSM model derived for HHP-induced molecular changes of β-Lg determined immunochemically showed that temperature (temp), pressure (p2) and the interaction between temperature and time (t) had statistically significant effects (p < 0.05). The optimal condition defined as minimum (β-Lg specific) IgG-binding derived from the model was 505 MPa at 56 °C with a holding time of 102 min (R2 of 0.81 and p-value of 0.01). The validation carried at the optimal condition and its surrounding region showed that the model to be underestimating the β-Lg structure modification. The molecular change of β-Lg was directly correlated with HHP-induced dimerization in this study, which followed a quadratic equation. The β-Lg dimers also resulted in the undetectable human IgE-binding.

Investigating the reliability of molecular estimates of evolutionary time when substitution rates and speciation rates vary

Background An accurate timescale of evolutionary history is essential to testing hypotheses about the influence of historical events and processes, and the timescale for evolution is increasingly derived from analysis of DNA sequences. But variation in the rate of molecular evolution complicates the inference of time from DNA. Evidence is growing for numerous factors, such as life history and habitat, that are linked both to the molecular processes of mutation and fixation and to rates of macroevolutionary diversification. However, the most widely used models of molecular rate variation, such as the uncorrelated and autocorrelated lognormal clocks, rely on idealised models of rate variation and molecular dating methods are rarely tested against complex models of rate change. One relationship that is not accounted for in molecular dating is the potential for interaction between molecular substitution rates and speciation, a relationship that has been supported by empirical studies in a growing number of taxa. If these relationships are as widespread as evidence indicates, they may have a significant influence on molecular dates. Results We simulate phylogenies and molecular sequences under three different realistic rate variation models - one in which speciation rates and substitution rates both vary but are unlinked, one in which they covary continuously and one punctuated model in which molecular change is concentrated in speciation events, using empirical case studies to parameterise realistic simulations. We test two commonly used "relaxed clock" molecular dating methods against these realistic simulations to explore the degree of error in molecular dates under each model. We find average divergence time inference errors ranging from 12% of node age for the unlinked model when reconstructed under an uncorrelated rate prior, to up to 93% when punctuated simulations are reconstructed under an autocorrelated prior. Conclusions We demonstrate the potential for substantial errors in molecular dates when both speciation rates and substitution rates vary between lineages. This study highlights the need for tests of molecular dating methods against realistic models of rate variation generated from empirical parameters and known relationships.

The Location of Substitutions and Bacterial Genome Arrangements

Increasing evidence supports the notion that different regions of a genome have unique rates of molecular change. This variation is particularly evident in bacterial genomes where previous studies have reported gene expression and essentiality tend to decrease, while substitution rates usually increases with increasing distance from the origin of replication. Genomic reorganization such as rearrangements occur frequently in bacteria and allow for the introduction and restructuring of genetic content, creating gradients of molecular traits along genomes. Here, we explore the interplay of these phenomena by mapping substitutions to the genomes of Escherichia coli, Bacillus subtilis, Streptomyces, and Sinorhizobium meliloti, quantifying how many substitutions have occurred at each position in the genome. Preceding work indicates that substitution rate significantly increases with distance from the origin. Using a larger sample size and accounting for genome rearrangements through ancestral reconstruction, our analysis demonstrates that the correlation between the number of substitutions and distance from the origin of replication is often significant but small and inconsistent in direction. Some replicons had a significantly decreasing trend (E. coli and the chromosome of S. meliloti), while others showed the opposite significant trend (B. subtilis, Streptomyces, pSymA and pSymB in S. meliloti). dN, dS and ω were examined across all genes and there was no significant correlation between those values and distance from the origin. This study highlights the impact that genomic rearrangements and location have on molecular trends in some bacteria, illustrating the importance of considering spatial trends in molecular evolutionary analysis. Assuming that molecular trends are exclusively in one direction can be problematic.

Mitochondrial Dysfunction Contributes to Ehlers-Danlos Syndrome - A Patient Presentation

A female patient with substantial history and physical findings of Ehlers-Danlos syndrome by systematic evaluation had a variant in the gene encoding the sixth subunit of mitochondrial ATP synthetase gene that produced a change from glycine to aspartic acid at position 132 of the MT-ATP6 protein (MT-ATP6 m.8921G>A, p.Gly132Asp). The mutation was heteroplasmic, affecting 32% of the mitochondria in blood leucocytes, was qualified as a pathogenic variant because of its significant molecular change, but was not detected in the maternal blood sample as might be expected for its low degree of heteroplasmy. The patient was shown to have typical findings of Ehlers-Danlos syndrome by comparison of 48 history and physical findings in her and a peer group of 32 teenage females with that diagnosis. None of the classical neurosensory or developmental symptoms of mitochondrial disease were present in mother or daughter, but the patient had symptoms, metabolite alterations during rest or exercise, and muscle biopsy changes that suggested mild mitochondrial dysfunction. She also had heterozygous variants of uncertain significance in the nuclear PLOD1, FLNA, and ATP2A genes by concomitant whole exome sequencing that could also contribute to her arthritis-adrenaline disorder. Mitochondrial dysfunction is proposed to influence neuromuscular components of connective tissue, acting through an articulo-autonomic dysplasia cycle to cause the typical joint-skin laxity and dysautonomia of Ehlers-Danlos syndrome.