The clinical picture of ERCC6L2 disease: from bone marrow failure to acute leukemia

Biallelic germ line excision repair cross-complementing 6 like 2 (ERCC6L2) variants strongly predispose to bone marrow failure (BMF) and myeloid malignancies, characterized by somatic TP53-mutated clones and erythroid predominance. We present a series of 52 subjects (35 families) with ERCC6L2 biallelic germ line variants collected retrospectively from 11 centers globally, with a follow-up of 1165 person-years. At initial investigations, 32 individuals were diagnosed with BMF and 15 with a hematological malignancy (HM). The subjects presented with 19 different variants of ERCC6L2, and we identified a founder mutation, c.1424delT, in Finnish patients. The median age of the subjects at baseline was 18 years (range, 2-65 years). Changes in the complete blood count were mild despite severe bone marrow (BM) hypoplasia and somatic TP53 mutations, with no significant difference between subjects with or without HMs. Signs of progressive disease included increasing TP53 variant allele frequency, dysplasia in megakaryocytes and/or erythroid lineage, and erythroid predominance in the BM morphology. The median age at the onset of HM was 37.0 years (95% CI, 31.5-42.5; range, 12-65 years). The overall survival (OS) at 3 years was 95% (95% CI, 85-100) and 19% (95% CI, 0-39) for patients with BMF and HM, respectively. Patients with myelodysplastic syndrome or acute myeloid leukemia with mutated TP53 undergoing hematopoietic stem cell transplantation had a poor outcome with a 3-year OS of 28% (95% CI, 0-61). Our results demonstrated the importance of early recognition and active surveillance in patients with biallelic germ line ERCC6L2 variants.

A germline exome analysis reveals harmful POT1 variants in multiple myeloma patients and families

Observations of inherited susceptibility to multiple myeloma have led to active research in defining predisposing genes to the disease. Here, we analysed 128 plasma cell dyscrasia patients' germline whole-exome sequencing data. Rare dominantly inherited pathogenic or likely pathogenic (P/LP) variant was found in 9.4% of the patients. Among the P/LP variants, CHEK2 (p. Thr410MetfsTer15) was the most prevalent (n = 5, 3.9%). Interestingly, P/LP variants in POT1 were identified in three patients (2.3%). Our findings broaden the spectrum of POT1-related cancers and demonstrate the importance of the germline genetic analysis in hematological malignancies.

Multifunctional PLGA/Parylene C Coating for Implant Materials: An Integral Approach for Biointerface Optimization

Functionalizing implant surfaces is critical for improving their performance. An integrated approach was employed to develop a multifunctional implant coating based on oxygen plasma-modified parylene C and drug-loaded, biodegradable poly(dl-lactide-co-glycolide) (PLGA). The key functional attributes of the coating (i.e., anti-corrosion, biocompatible, anti-infection, and therapeutic) were thoroughly characterized at each fabrication step by spectroscopic, microscopic, and biologic methods and at different scales, ranging from molecular, through the nano- and microscales to the macroscopic scale. The chemistry of each layer was demonstrated separately, and their mutual affinity was shown to be indispensable for the development of versatile coatings for implant applications.

Repeatability of knee impulsive loading measurements with skin-mounted accelerometers and lower limb surface electromyographic recordings during gait in knee osteoarthritic and asymptomatic individuals

OBJECTIVES

To determine the repeatability of knee joint impulsive loading measurements with skin-mounted accelerometers (SMAs) and lower limb surface electromyography (EMG) recordings during gait.

METHODS

Triaxial SMA and EMG from 4 muscles during level and stair walking in nine healthy and nine knee osteoarthritis (OA) subjects were used. The initial peak acceleration (IPA), root mean square (RMS), maximal acceleration transient rate (ATRmax) and mean EMG activity (EMGact) were calculated. The coefficient of variation (CV) and the intraclass correlation coefficient (ICC) were calculated to measure repeatability.

RESULTS

The CV and ICC of RMS accelerations ranged from 4.9% to 10.9% and from 0.69 to 0.96 in both study groups during level walking. The CV and ICC of IPA and ATRmax varied from 7.7% to 14.2% and from 0.85 to 0.99 during level and stairs up walking in healthy subjects. The CV and ICC of EMGact ranged from 8.3% to 31.7% and from 0.16 to 0.97 in both study groups.

CONCLUSIONS

RMS accelerations exhibited good repeatability during walking in healthy and knee OA subjects. The repeatability of EMG measurements was acceptable in healthy subjects depending on the measured muscles.

LDI-MS examination of oxygen plasma modified polymer for designing tailored implant biointerfaces

A versatile parylene C coating for biomaterials was fabricated by the mild oxygen plasma treatment and examined by the use of LDI-MS..

In vitro and in vivo degradation profile of aliphatic polyesters subjected to electron beam sterilization

Degradation characteristics in response to electron beam sterilization of designed and biodegradable aliphatic polyester scaffolds are relevant for clinically successful synthetic graft tissue regeneration. Scaffold degradation in vitro and in vivo were documented and correlated to the macroscopic structure and chemical design of the original polymer. The materials tested were of inherently diverse hydrophobicity and crystallinity: poly(L-lactide) (poly(LLA)) and random copolymers from L-lactide and ε-caprolactone or 1,5-dioxepan-2-one, fabricated into porous and non-porous scaffolds. After sterilization, the samples underwent hydrolysis in vitro for up to a year. In vivo, scaffolds were surgically implanted into rat calvarial defects and retrieved for analysis after 28 and 91days. In vitro, poly(L-lactide-co-1,5-dioxepan-2-one) (poly(LLA-co-DXO)) samples degraded most rapidly during hydrolysis, due to the pronounced chain-shortening reaction caused by the sterilization. This was indicated by the rapid decrease in both mass and molecular weight of poly(LLA-co-DXO). Poly(L-lactide-co-ε-caprolactone) (poly(LLA-co-CL)) samples were also strongly affected by sterilization, but mass loss was more gradual; molecular weight decreased rapidly during hydrolysis. Least affected by sterilization were the poly(LLA) samples, which subsequently showed low mass loss rate and molecular weight decrease during hydrolysis. Mechanical stability varied greatly: poly(LLA-co-CL) withstood mechanical testing for up to 182 days, while poly(LLA) and poly(LLA-co-DXO) samples quickly became too brittle. Poly(LLA-co-DXO) samples unexpectedly degraded more rapidly in vitro than in vivo. After sterilization by electron beam irradiation, the three biodegradable polymers present widely diverse degradation profiles, both in vitro and in vivo. Each exhibits the potential to be tailored to meet diverse clinical tissue engineering requirements.

Time-varying spectrum estimation of heart rate variability signals with Kalman smoother algorithm

A time-varying parametric spectrum estimation method for analyzing dynamics of heart rate variability (HRV) signals is presented. In the method, HRV signal is first modeled with a time-varying autoregressive model and the model parameters are solved recursively with a Kalman smoother algorithm. Time-varying spectrum estimates are then obtained from the estimated model parameters. The obtained spectrum can be further decomposed into separate components, which is especially advantageous in HRV applications where low frequency (LF) and high frequency (HF) components are generally aimed to be distinguished. As case studies, the dynamics of HRV signals recorded during 1) orthostatic test, 2) exercise test and 3) simulated driving task are analyzed.

Headspace solid-phase microextraction--a tool for new insights into the long-term thermo-oxidation mechanism of polyamide 6.6

Low-molecular-mass products formed during thermo-oxidation of polyamide 6.6 at 100 degrees C were extracted by headspace solid-phase microextraction and identified by GC-MS. A total of 18 degradation products of polyamide 6.6 were identified. In addition some low-molecular-mass products originating from the lubricants were detected. The identified degradation products were categorized into four groups where compounds within each group contain the same structural feature. In groups A, B and C several new thermo-oxidation products of polyamide 6.6 were identified including cyclic imides, pyridines and structural fragments from the original polyamide chain. 1-Pentyl-2,5-pyrrolidinedione (pentylsuccinimide) showed the largest increase in abundance during oxidation. The cyclopentanones in group D were already present in the un-aged material. Their amounts decreased during ageing and they are thus not formed during thermo-oxidation of polyamide 6.6 at 100 degrees C. The identified thermo-oxidation products can be formed as a result of extensive oxidation of the hexamethylenediamine unit in the polyamide backbone. The degradation products pattern shows that the long-term thermo-oxidative degradation, just like thermal degradation and photo-oxidation of polyamide 6.6, starts at the N-vicinal methylene groups.

Hypermethylation of calcitonin gene regulatory sequences in human breast cancer as revealed by genomic sequencing

DNA methylation has been studied intensively during the past years in order to elucidate its role in the regulation of gene expression, gene imprinting and cancer progression. Earlier studies have shown that a general genomic under-methylation is associated with chronic lymphocytic leukemia and metastatic prostate cancer. Site-specific methylation changes, as revealed by the use of methylation-sensitive restriction enzymes, have been reported to occur in the promotor region of the calcitonin gene in chronic myeloid leukemia as it progresses from the chronic phase to blast crisis, in non-Hodgkin's lymphoid neoplasms and in non-lymphocytic leukemia. We have now explored possible methylation changes associated with benign and malignant breast tumors. Two approaches were employed: (i) chemical determination of general genomic methylation status and (ii) base-specific analysis of the methylation changes in the promoter of the calcitonin gene with the aid of genomic sequencing. The results did not reveal any changes of total DNA 5-methylcytosine content in ductal carcinoma of breast in comparison with benign tumors. There was a small, yet significant, increase in 5-methylcytosine content in lobular carcinoma. Genomic sequencing of the promoter region of the calcitonin gene, however, revealed a striking hypermethylation at or around the transcription start site of the gene in ductal carcinomas. In benign tumors and lobular carcinomas, this region was either entirely unmethylated or only slightly methylated. The latter changes may reflect a regional hypermethylation of the short arm of chromosome 11, which harbors, in addition to the calcitonin gene, a number of putative or established tumor-suppressor genes. Our results demonstrate that genomic sequencing in its present form can be used for a reliable and precise DNA methylation analysis of primary human tumors.

Carcinoembryonic antigen is expressed on endothelial cells. A putative mediator of tumor cell extravasation and metastasis

Carcinoembryonic antigen (CEA) is a highly glycosylated cell surface protein. It is produced in large amounts in essentially all colon and several other adenocarcinomas. It has therefore been widely used as a clinical tumor marker. CEA is also a member of the immunoglobulin superfamily. Members of this family, such as ICAM-1, ICAM-2, VCAM-1 and NCAM, are known to participate in cell-cell adhesion. Similarly, the intercellular adhesion properties of CEA have been documented: it has been shown to mediate homotypic adhesion of cultured human colon adenocarcinoma cell lines. In this study we show for the first time that CEA is expressed on cultured human umbilical vein endothelial cells and on the endothelial cell line Ea.hy926. The expression of CEA on cultured endothelial cells can be enhanced by TNF-alpha or IFN-gamma, and decreased by IL-4. We demonstrate using immunohistochemistry that anti-CEA monoclonal antibody reacted with FVIII-positive endothelium in tissue sections prepared from lymph nodes. Finally, we were able to show that CEA-positive breast carcinoma cells bind to purified CEA protein, whereas CEA-negative breast carcinoma cells do not. These results reveal for the first time that endothelial cells express CEA on the cell surface and suggest that CEA-expressing adenocarcinomas could adhere to endothelial cells via CEA-CEA interaction, thus facilitating tumor cell extravasation and hematogenic metastasis.

Down-regulation of monocytic VLA-4 leads to a decreased adhesion to VCAM-1

The alpha 4 beta 1 integrin VLA-4 is expressed on practically all leukocytes, except on mature granulocytes. Here we show that in vitro treatment of monocytic cells with phorbol-12-myristate-13-acetate (PMA) leads to a selective decrease in the VLA-4 alpha-chain expression, both at the RNA and protein level. Meanwhile the expression of beta 1 and that of alpha 5, another alpha-chain associating with beta 1, was seen to increase. The decrease of alpha 4 expression was restricted to monocytic cells, and was not observed on other VLA-4-positive cells tested (MOLT-4 T cells and HOS sarcoma cells). The down-regulation of the VLA-4 alpha-chain was followed by a decreased binding capacity of the cells to recombinant VCAM-1. This data indicates that while previous findings show that the integrin-dependent adhesion may rapidly be regulated by altering the avidity of the interacting molecules, their quantitative modulation also has a clear impact on adhesion.