Interspecies differences with in vitro and in vivo models of vascular tissue engineering

In arterial replacement there is a clear clinical need for a functional substitute possessing appropriate haemocompatible properties to be implanted as small diameter artery. Endothelial cell seeding constitutes an appreciated method to improve blood compatibility on the condition that cells firmly adhere to the support. Along this way, an innovative technique based on multilayered polyelectrolyte films (PEM) as cell adhesive substrate was previously validated in vitro and in vivo in a small-animal model. In this study, we extended the work on a larger animal (sheep) to validate furthermore the paradigm of PEM functionalization for vascular substitutes. We tested in vitro: the efficiency of PEM to induce endothelial progenitor differentiation in sheep endothelial cells; the ability of PEM to sustain cell proliferation and allow resistance to shear stress; the fate of PEM-coated de-endothelialized human saphenous veins under flow conditions, a prerequisite step before in vivo experiments. Despite in vitro differences we were encouraged by testing in vivo PEM-coated prosthesis as carotid replacement in sheep, but without success. In order to explain the implantation failure, an in vitro haemocompatibility evaluation was performed that highlighted interspecies differences able to explain, at least in part, the graft failure obtained.     

Isolation of Bokeloh bat lyssavirus in Myotis nattereri in France

Bokeloh bat lyssavirus (BBLV) was found in Myotis nattereri for the first time in northeastern France in July 2012. The complete genome sequence of the virus from the infected Natterer’s bat was determined by whole-genome sequencing and compared to that of the first BBLV strain isolated in 2010 in Germany and with those of all currently identified lyssaviruses. The French isolate [KC169985] showed 98.7 % nucleotide sequence identity to the German BBLV strain [JF311903]. Several organs of the infected French bat were examined by classical rabies diagnostic methods: fluorescent antibody test, cell culture inoculation test and RT-qPCR. Antigen, infectious virus and high viral RNA levels were found in both the brain and salivary glands. Traces of genomic RNA were detected in the bladder, kidney and lung tissue. The results of an investigation of the distribution of lyssaviruses with the detection of infectious virus in the salivary glands suggest a possible mode of transmission of the virus.     

A 137‐kb deletion within the Potocki–Shaffer syndrome interval on chromosome 11p11.2 associated with developmental delay and hypotonia

Potocki–Shaffer syndrome (PSS) is a rare disorder caused by haploinsufficiency of genes located on the proximal short arm of chromosome 11 (11p11.2p12). Classic features include biparietal foramina, multiple exostoses, profound hypotonia, dysmorphic features, and developmental delay/intellectual disability. Fewer than 40 individuals with PSS have been reported, with variable clinical presentations due in part to disparity in deletion sizes. We report on a boy who presented for initial evaluation at age 13 months because of a history of developmental delay, hypotonia, subtle dysmorphic features, and neurobehavioral abnormalities. SNP microarray analysis identified a 137 kb deletion at 11p11.2, which maps within the classically defined PSS interval. This deletion results in haploinsufficiency for all or portions of six OMIM genes: SLC35C1, CRY2, MAPK8IP1, PEX16, GYLTL1B, and PHF21A. Recently, translocations interrupting PHF21A have been associated with intellectual disability and craniofacial anomalies similar to those seen in PSS. The identification of this small deletion in a child with developmental delay and hypotonia provides further evidence for the genetic basis of developmental disability and identifies a critical region sufficient to cause hypotonia in this syndrome. Additionally, this case illustrates the utility of high resolution genomic approaches in correlating clinical phenotypes with specific genes in contiguous gene deletion syndromes. © 2012 Wiley Periodicals, Inc.     

Description of a Large Family with Autosomal Dominant Hypercholesterolemia Associated with the APOE p.Leu167del Mutation

Apolipoprotein (apo) E mutants are associated with type III hyperlipoproteinemia characterized by high cholesterol and triglycerides levels. Autosomal dominant hypercholesterolemia (ADH), due to the mutations in the LDLR, APOB, or PCSK9 genes, is characterized by an isolated elevation of cholesterol due to the high levels of low‐density lipoproteins (LDLs). We now report an exceptionally large family including 14 members with ADH. Through genome‐wide mapping, analysis of regional/functional candidate genes, and whole exome sequencing, we identified a mutation in the APOE gene, c.500_502delTCC/p.Leu167del, previously reported associated with sea‐blue histiocytosis and familial combined hyperlipidemia. We confirmed the involvement of the APOE p.Leu167del in ADH, with (1) a predicted destabilization of an alpha‐helix in the binding domain, (2) a decreased apo E level in LDLs, and (3) a decreased catabolism of LDLs. Our results show that mutations in the APOE gene can be associated with bona fide ADH.     

Detection of multiple viral and bacterial infections in acute exacerbation of chronic obstructive pulmonary disease: A pilot prospective study

Few studies have evaluated the contribution of multiple virus and bacterial infections in acute exacerbation of chronic obstructive pulmonary disease. This study estimated the burden of multiple viral and bacterial respiratory infections in moderate to very severe chronic obstructive pulmonary disease patients that were prospectively followed‐up during a 12‐month pilot study. Clinical data were collected monthly and sputum was collected at the time of each acute exacerbation event. Classical culture techniques for bacteria and multiplex polymerase chain reaction (PCR) and microarray detection assays were performed to identify viral and atypical bacterial pathogens in the sputum. Overall, 51 patients were included and 45 acute exacerbation events were investigated clinically and microbiologically. Among the 45 acute exacerbation events, 44% had evidence of viral infection involving human rhinovirus (HRV) and metapneumovirus (hMPV) in 20% and 18%, respectively. Intracellular bacteria were not found in sputum by PCR. Common bacterial pathogens were identified in 42% of acute exacerbation patients, most frequently Branhamella catarrhalis, Streptococcus pneumoniae and Haemophilus influenzae. Viral or virus and bacteria co‐infections were detected in 27% of acute exacerbation events (n = 12) with HRV and hMPV involved in 92% of cases. Patients with co‐infections did not present greater clinical severity scores at exacerbation and more recurrence of acute exacerbation events at 3 and 6 months than those with single infections (P > 0.4). These results suggest that HRV and hMPV may be contributors or cofactors of AECOPD. These findings indicate that viral or virus and bacterial co‐infections do not impact significantly on the clinical severity of acute exacerbation of chronic obstructive pulmonary disease and recurrence at 3 and 6 months. J. Med. Virol. 85:866–873, 2013. © 2013 Wiley Periodicals, Inc.     

Characterization of the human CD4+ T‐cell repertoire specific for major histocompatibility class I‐restricted antigens

While CD4⁺ T lymphocytes usually recognize antigens in the context of major histocompatibility (MHC) class II alleles, occurrence of MHC class‐I restricted CD4⁺ T cells has been reported sporadically. Taking advantage of a highly sensitive MHC tetramer‐based enrichment approach allowing detection and isolation of scarce Ag‐specific T cells, we performed a systematic comparative analysis of HLA‐A*0201‐restricted CD4⁺ and CD8⁺ T‐cell lines directed against several immunodominant viral or tumoral antigens. CD4⁺ T cells directed against every peptide‐MHC class I complexes tested were detected in all donors. These cells yielded strong cytotoxic and T helper 1 cytokine responses when incubated with HLA‐A2⁺ target cells carrying the relevant epitopes. HLA‐A2‐restricted CD4⁺ T cells were seldom expanded in immune HLA‐A2⁺ donors, suggesting that they are not usually engaged in in vivo immune responses against the corresponding peptide‐MHC class I complexes. However, these T cells expressed TCR of very high affinity and were expanded following ex vivo stimulation by relevant tumor cells. Therefore, we describe a versatile and efficient strategy for generation of MHC class‐I restricted T helper cells and high affinity TCR that could be used for adoptive T‐cell transfer‐ or TCR gene transfer‐based immunotherapies.     

Scoping Review on Search Queries and Social Media for Disease Surveillance: A Chronology of Innovation

Background

The threat of a global pandemic posed by outbreaks of influenza H5N1 (1997) and Severe Acute Respiratory Syndrome (SARS, 2002), both diseases of zoonotic origin, provoked interest in improving early warning systems and reinforced the need for combining data from different sources. It led to the use of search query data from search engines such as Google and Yahoo! as an indicator of when and where influenza was occurring. This methodology has subsequently been extended to other diseases and has led to experimentation with new types of social media for disease surveillance.

Objective

The objective of this scoping review was to formally assess the current state of knowledge regarding the use of search queries and social media for disease surveillance in order to inform future work on early detection and more effective mitigation of the effects of foodborne illness.

Methods

Structured scoping review methods were used to identify, characterize, and evaluate all published primary research, expert review, and commentary articles regarding the use of social media in surveillance of infectious diseases from 2002-2011.

Results

Thirty-two primary research articles and 19 reviews and case studies were identified as relevant. Most relevant citations were peer-reviewed journal articles (29/32, 91%) published in 2010-11 (28/32, 88%) and reported use of a Google program for surveillance of influenza. Only four primary research articles investigated social media in the context of foodborne disease or gastroenteritis. Most authors (21/32 articles, 66%) reported that social media-based surveillance had comparable performance when compared to an existing surveillance program. The most commonly reported strengths of social media surveillance programs included their effectiveness (21/32, 66%) and rapid detection of disease (21/32, 66%). The most commonly reported weaknesses were the potential for false positive (16/32, 50%) and false negative (11/32, 34%) results. Most authors (24/32, 75%) recommended that social media programs should primarily be used to support existing surveillance programs.

Conclusions

The use of search queries and social media for disease surveillance are relatively recent phenomena (first reported in 2006). Both the tools themselves and the methodologies for exploiting them are evolving over time. While their accuracy, speed, and cost compare favorably with existing surveillance systems, the primary challenge is to refine the data signal by reducing surrounding noise. Further developments in digital disease surveillance have the potential to improve sensitivity and specificity, passively through advances in machine learning and actively through engagement of users. Adoption, even as supporting systems for existing surveillance, will entail a high level of familiarity with the tools and collaboration across jurisdictions.     

Novel mutations in CRB1 and ABCA4 genes cause Leber congenital amaurosis and Stargardt disease in a Swedish family

This study aimed to identify genetic mechanisms underlying severe retinal degeneration in one large family from northern Sweden, members of which presented with early-onset autosomal recessive retinitis pigmentosa and juvenile macular dystrophy. The clinical records of affected family members were analysed retrospectively and ophthalmological and electrophysiological examinations were performed in selected cases. Mutation screening was initially performed with microarrays, interrogating known mutations in the genes associated with recessive retinitis pigmentosa, Leber congenital amaurosis and Stargardt disease. Searching for homozygous regions with putative causative disease genes was done by high-density SNP-array genotyping, followed by segregation analysis of the family members. Two distinct phenotypes of retinal dystrophy, Leber congenital amaurosis and Stargardt disease were present in the family. In the family, four patients with Leber congenital amaurosis were homozygous for a novel c.2557C>T (p.Q853X) mutation in the CRB1 gene, while of two cases with Stargardt disease, one was homozygous for c.5461-10T>C in the ABCA4 gene and another was carrier of the same mutation and a novel ABCA4 mutation c.4773+3A>G. Sequence analysis of the entire ABCA4 gene in patients with Stargardt disease revealed complex alleles with additional sequence variants, which were evaluated by bioinformatics tools. In conclusion, presence of different genetic mechanisms resulting in variable phenotype within the family is not rare and can challenge molecular geneticists, ophthalmologists and genetic counsellors.     

Magnetic resonance elastography with guided pressure waves

Magnetic resonance elastography aims to non-invasively and remotely characterize the mechanical properties of living tissues. To quantitatively and regionally map the shear viscoelastic moduli in vivo, the technique must achieve proper mechanical excitation throughout the targeted tissues. Although it is straightforward, ante manibus, in close organs such as the liver or the breast, which practitioners clinically palpate already, it is somewhat fortunately highly challenging to trick the natural protective barriers of remote organs such as the brain. So far, mechanical waves have been induced in the latter by shaking the surrounding cranial bones. Here, the skull was circumvented by guiding pressure waves inside the subject's buccal cavity so mechanical waves could propagate from within through the brainstem up to the brain. Repeatable, reproducible and robust displacement fields were recorded in phantoms and in vivo by magnetic resonance elastography with guided pressure waves such that quantitative mechanical outcomes were extracted in the human brain.