Molecular genetics of usher syndrome

Usher syndrome (USH) is inherited in an autosomal recessive mode. The disease is characterized by hearing loss, progressing vision loss, and vestibular dysfunction. In most cases, it is the reason for deafness and blindness in school-age children. The prevalence of USH in the main population is estimated as 4.4 per 100000 individuals, approximately. The prevalence of heterozygous carriers can reach 1 per 70 normally hearing individuals. There is currently no effective treatment of USH. The patients are provided with hearing aids, but, in case of severe hearing impairement these aids give no effect. In view of this, developing diagnostic methods is important. It is believed that molecular genetic investigations will enable early diagnostics of the syndrome.     

Tests for the diagnosis of Clostridium difficile infection: the next generation

Clostridium difficile (C. difficile) causes 25-30% of cases of antibiotic associated diarrhea and most cases of pseudomembranous colitis. Patients presenting with diarrhea after hospitalization for 3 or more days should be tested for C. difficile. There are many options available for testing, each of which has inherent advantages and disadvantages. Most laboratories perform toxin testing using an enzyme immunoassay method. In general these tests have sensitivities ranging from 60 to 70% and specificities of 98%. When using these methods, symptomatic patients with negative tests should be tested by another more sensitive method. Until recently, cell culture cytotoxicity neutralization assays (CCNAs) were considered the gold standard in the U.S. A two-step algorithm using an EIA for glutamate dehydrogenase detection followed by testing positives using CCNA, offered an improved alternative until the availability of molecular assays. Although early studies that compared the GDH assay to CCNA demonstrated high sensitivity and negative predictive values, more recent comparisons to toxigenic culture and PCR have shown the sensitivity to be in the mid to high 80's. When testing using a sensitive assay, repeat testing is not cost-effective. Outbreaks caused by a toxin variant epidemic strain have renewed interest in bacterial culture. Toxigenic culture has emerged as the new gold standard against which newer assays should be compared. However, there is no agreed upon standard method for culture performance. At least 4 FDA cleared nucleic acid amplification assays are available to clinical laboratories and several of these have been well evaluated in the literature. Because these assays detect a gene that encodes toxin and not the toxin itself it is important that laboratories test only patients with diarrhea. These molecular assays have been shown to be superior to toxin EIAs, CCNA and 2-step algorithms, but not to toxigenic culture. More studies are needed to assess the impact of molecular tests on treatment and nosocomial spread of Clostridium difficile infections.     

Next generation sequencing-based molecular diagnosis of retinitis pigmentosa: identification of a novel genotype-phenotype correlation and clinical refinements

Retinitis pigmentosa (RP) is a devastating form of retinal degeneration, with significant social and professional consequences. Molecular genetic information is invaluable for an accurate clinical diagnosis of RP due to its high genetic and clinical heterogeneity. Using a gene capture panel that covers 163 of the currently known retinal disease genes, including 48 RP genes, we performed a comprehensive molecular screening in a collection of 123 RP unsettled probands from a wide variety of ethnic backgrounds, including 113 unrelated simplex and 10 autosomal recessive RP (arRP) cases. As a result, 61 mutations were identified in 45 probands, including 38 novel pathogenic alleles. Interestingly, we observed that phenotype and genotype were not in full agreement in 21 probands. Among them, eight probands were clinically reassessed, resulting in refinement of clinical diagnoses for six of these patients. Finally, recessive mutations in CLN3 were identified in five retinal degeneration patients, including four RP probands and one cone-rod dystrophy patient, suggesting that CLN3 is a novel non-syndromic retinal disease gene. Collectively, our results underscore that, due to the high molecular and clinical heterogeneity of RP, comprehensive screening of all retinal disease genes is effective in identifying novel pathogenic mutations and provides an opportunity to discover new genotype-phenotype correlations. Information gained from this genetic screening will directly aid in patient diagnosis, prognosis, and treatment, as well as allowing appropriate family planning and counseling.     

Adaptation genomics: the next generation

Understanding the genetics of how organisms adapt to changing environments is a fundamental topic in modern evolutionary ecology. The field is currently progressing rapidly because of advances in genomics technologies, especially DNA sequencing. The aim of this review is to first briefly summarise how next generation sequencing (NGS) has transformed our ability to identify the genes underpinning adaptation. We then demonstrate how the application of these genomic tools to ecological model species means that we can start addressing some of the questions that have puzzled ecological geneticists for decades such as: How many genes are involved in adaptation? What types of genetic variation are responsible for adaptation? Does adaptation utilise pre-existing genetic variation or does it require new mutations to arise following an environmental change?     

Evolutionary ecology: next generation inference

Oak forests support a rich ecology of fellow travellers, but how do these fare when the forests move during glacial cycles? The answers revealed by a new study are important for ecology, but being able to get answers at all highlights a turning point in evolutionary inference.     

Remote controlling of CAR-T cells and toxicity management: Molecular switches and next generation CARs

Cell-based immunotherapies have been selected for the front-line cancer treatment approaches. Among them, CAR-T cells have shown extraordinary effects in hematologic diseases including chemotherapy-resistant acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), and non-Hodgkin lymphoma (NHL). In this approach, autologous T cells isolated from the patient''s body genetically engineered to express a tumor specific synthetic receptor against a tumor antigen, then these cells expanded ex vivo and re-infusion back to the patient body. Recently, significant clinical response and high rates of complete remission of CAR T cell therapy in B-cell malignancies led to the approval of Kymriah and Yescarta (CD19-directed CAR-T cells) were by FDA for treatment of acute lymphoblastic leukemia and diffuse large B-cell lymphoma. Despite promising therapeutic outcomes, CAR T cells also can elicit the immune-pathologic effects, such as Cytokine Release Syndrome (CRS), Tumor Lysis Syndrome (TLS), and on-target off-tumor toxicity, that hampered its application. Ineffective control of these highly potent synthetic cells causes discussed potentially life-threatening toxicities, so researchers have developed several mechanisms to remote control CAR T cells. In this paper, we briefly review the introduced toxicities of CAR-T cells, then describe currently existing control approaches and review their procedure, pros, and cons.     

Hallmarks of cancer: the next generation

The hallmarks of cancer comprise six biological capabilities acquired during the multistep development of human tumors. The hallmarks constitute an organizing principle for rationalizing the complexities of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis. Underlying these hallmarks are genome instability, which generates the genetic diversity that expedites their acquisition, and inflammation, which fosters multiple hallmark functions. Conceptual progress in the last decade has added two emerging hallmarks of potential generality to this list-reprogramming of energy metabolism and evading immune destruction. In addition to cancer cells, tumors exhibit another dimension of complexity: they contain a repertoire of recruited, ostensibly normal cells that contribute to the acquisition of hallmark traits by creating the "tumor microenvironment." Recognition of the widespread applicability of these concepts will increasingly affect the development of new means to treat human cancer.     

Bead-based microfluidic immunoassays: the next generation

Microfluidic devices possess many advantages like high throughput, short analysis time, small volume and high sensitivity that fulfill all the important criteria of an immunoassay used for clinical diagnoses, environmental analyses and biochemical studies. These devices can be made from a few different materials, with polymers presently emerging as the most popular choice. Other than being optically clear, non-toxic and cheap, polymers can also be easily fabricated with a variety of techniques. In addition, there are many polymer surface modification methods available to improve the efficiency of these devices. Unfortunately, current microfluidic immunoassays have limited multiplexing capability compared to flow cytometric assays. Flow cytometry employ the use of encoded microbeads in contrast with normal or paramagnetic microbeads applied in current microfluidic devices. The encoded microbead is the key in providing multiplexing capability to the assay by allowing multi-analyte analysis. Using several unique sets of code, different analytes can be detected in a single assay by tracing the identity of individual beads. The same principle could be applied to microfluidic immunoassays in order to retain all the advantages of a fluidic device and significantly improve multiplexing capability.     

Sequencing antibody repertoires: The next generation

Genomic studies have been revolutionized by the use of next generation sequencing (NGS), which delivers huge amounts of sequence information in a short span of time. The number of applications for NGS is rapidly expanding and significantly transforming many areas of life sciences. The field of antibody research and discovery is no exception. Several recent studies have harnessed the power of NGS for analyzing natural or synthetic immunoglobulin repertoires with unprecedented resolution and exploring alternative paths for antibody discovery. Thus, appreciating and then exploiting these advances is essential for staying at the edge of antibody innovation.Key words: next generation sequencing, phage display, hybridoma, antibody discovery, in vitro selection, immunization     

Vascular tissue engineering: the next generation

It is the ultimate goal of tissue engineering: an autologous tissue engineered vascular graft (TEVG) that is immunologically compatible, nonthrombogenic, and can grow and remodel. Currently, native vessels are the preferred vascular conduit for procedures such as coronary artery bypass (CABG) or peripheral bypass surgery. However, in many cases these are damaged, have already been harvested, or are simply unusable. The use of synthetic conduits is severely limited in smaller diameter vessels due to increased incidence of thrombosis, infection, and graft failure. Current research has therefore energetically pursued the development of a TEVG that can incorporate into a patient's circulatory system, mimic the vasoreactivity and biomechanics of the native vasculature, and maintain long-term patency.     

Bio-electrosprays: the next generation of electrified jets

Biological electrosprays are rapidly becoming a robust means by which to engineer living organisms for applications ranging from tissue repair to developmental biology. We previously reported the ability to electrospray living organisms without compromising their viability, but found it challenging to achieve stability in the jetting of these organisms as a result of the chemical properties of the living cellular suspensions. Jet stability is required for the generation of a near-mono distribution of droplets, which is necessary for the development of electrospray technology as a "drop and place" biotechnique. Recently, we determined the conditions needed to achieve jet stability and were able to generate droplets with a near-mono distribution (<50 microm). In this communication, we elucidate the relationship between jet behaviour and droplet size under stable jetting conditions, with a view to further reducing the droplet size to deposit a single living cell within a droplet. We believe that this level of resolution will make electrospray jetting superior amongst the jet-based biotechnologies presently being developed for the engineering of biological architectures comprised of living cells.     

Regulation of p53: The next generation

The p53 protein is one of the most important tumor suppressor proteins. The most prevailing property of this tumor suppressor protein is its activation in response to DNA damage which counteracts the propagation of genetic alterations to daughter cells under conditions that provoke mutagenesis. In response to DNA damage and some other kinds of cellular stress the turnover of p53 is reduced or completely switched-off, which leads to a strong increase in the amount of the p53 protein and subsequently to the implementation of cell cycle arrest and apoptosis. Although post-translational modifications of p53 certainly contribute to the activation of p53 under physiologic conditions, an increase in the amount of the protein e.g. after overexpression, is sufficient for p53's deadly activities. This makes this tumor suppressor protein an interesting target for cancer therapy. This article summarizes the most important principles for the regulation of p53, with a particular focus on recent findings. Furthermore, open questions and possible future directions shall be discussed.     

两种不同途径子宫全切术的临床效果比较

比较腹腔镜辅助阴式子宫全切术(LAVH)与经腹部子宫全切术(TAH)的临床效果。方法:收集我院2004年6月至2006年1月接受以上两种途径子宫切除术的病例共150例的临床资料。其中LAVH100例(LAVH组),TAH50例(TAH组),比较两组手术时间、术中出血量、术后病率及住院时间等。结果:LAVH组术中出血量、术后病率及住院时间均明显小于TAH组,差异有统计学意义(P＜0．01),但LAVH组手术时间与TAH组比较,差异无统计学意义(P＞0．5)。结论:LAVH创伤小、病人痛苦少,术后恢复快。