Creation of an international registry to support discovery in schwannomatosis.

Schwannomatosis is a tumor suppressor syndrome that causes multiple tumors along peripheral nerves. Formal diagnostic criteria were first published in 2005. Variability in clinical presentation and a relative lack of awareness of the syndrome have contributed to difficulty recognizing affected individuals and accurately describing the natural history of the disorder. Many critical questions such as the mutations underlying schwannomatosis, genotype-phenotype correlations, inheritance patterns, pathologic diagnosis of schwannomatosis-associated schwannomas, tumor burden in schwannomatosis, the incidence of malignancy, and the effectiveness of current, or new treatments remain unanswered. A well-curated registry of schwannomatosis patients is needed to facilitate research in field. An international consortium of clinicians and scientists across multiple disciplines with expertise in schwannomatosis was established and charged with the task of designing and populating a schwannomatosis patient registry. The International Schwannomatosis Registry (ISR) was built around key data points that allow confirmation of the diagnosis and identification of potential research subjects to advance research to further the knowledge base for schwannomatosis. A registry with 389 participants enrolled to date has been established. Twenty-three additional subjects are pending review. A formal process has been established for scientific investigators to propose research projects, identify eligible subjects, and seek collaborators from ISR sites. Research collaborations have been created using the information collected by the registry and are currently being conducted. The ISR is a platform from which multiple research endeavors can be launched, facilitating connections between affected individuals interested in participating in research and researchers actively investigating a variety of aspects of schwannomatosis. © 2016 Wiley Periodicals, Inc.

Bevacizumab treatment for symptomatic spinal ependymomas in neurofibromatosis type 2.

BACKGROUND: Neurofibromatosis type 2 (NF2) is a tumor suppressor syndrome associated with vestibular schwannomas, meningiomas, and spinal ependymomas. There have been anecdotal reports of radiographic response of spinal ependymomas in NF2 patients being treated for progressive vestibular schwannomas with bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF). AIMS: The aim of this study was to review the clinical effects of bevacizumab treatment for symptomatic, NF2-associated ependymomas METHODS: We conducted a retrospective review of all patients with NF2 treated with bevacizumab for symptomatic ependymoma at three NF2 specialty centers. Tumor size was evaluated by linear measurements; radiographic response was defined as >20% reduction in tumor size. We also performed immunohistochemical evaluation of NF2-associated symptomatic ependymomas from five patients, including two from this clinical series. RESULTS: Eight patients with NF2 and symptomatic ependymoma were treated with bevacizumab. All patients had subjective clinical improvement with bevacizumab, although only five of eight patients evaluated had radiographic response. All tumors expressed VEGF-R2. Four of five evaluated ependymomas expressed VEGF-R1; one without VEGF-R1 expression was from a patient who showed clinical but not radiographic response. CONCLUSIONS: Treatment using bevacizumab improved symptoms related to NF2-associated ependymomas, often without concurrent radiographic response. This treatment effect may be related to VEGF-R1 expression in NF2-associated ependymoma.

Unfolded protein ensembles, folding trajectories, and refolding rate prediction.

Computer simulations can provide critical information on the unfolded ensemble of proteins under physiological conditions, by explicitly characterizing the geometrical properties of the diverse conformations that are sampled in the unfolded state. A general computational analysis across many proteins has not been implemented however. Here, we develop a method for generating a diverse conformational ensemble, to characterize properties of the unfolded states of intrinsically disordered or intrinsically folded proteins. The method allows unfolded proteins to retain disulfide bonds. We examined physical properties of the unfolded ensembles of several proteins, including chemical shifts, clustering properties, and scaling exponents for the radius of gyration with polymer length. A problem relating simulated and experimental residual dipolar couplings is discussed. We apply our generated ensembles to the problem of folding kinetics, by examining whether the ensembles of some proteins are closer geometrically to their folded structures than others. We find that for a randomly selected dataset of 15 non-homologous 2- and 3-state proteins, quantities such as the average root mean squared deviation between the folded structure and unfolded ensemble correlate with folding rates as strongly as absolute contact order. We introduce a new order parameter that measures the distance travelled per residue, which naturally partitions into a smooth "laminar" and subsequent "turbulent" part of the trajectory. This latter conceptually simple measure with no fitting parameters predicts folding rates in 0 M denaturant with remarkable accuracy (r = -0.95, p = 1 × 10(-7)). The high correlation between folding times and sterically modulated, reconfigurational motion supports the rapid collapse of proteins prior to the transition state as a generic feature in the folding of both two-state and multi-state proteins. This method for generating unfolded ensembles provides a powerful approach to address various questions in protein evolution, misfolding and aggregation, transient structures, and molten globule and disordered protein phases.

Building on the success of the Expanded Programme on Immunization: enhancing the focus on disease prevention and control.

The Expanded Programme on Immunization (EPI) has succeeded in establishing a vaccine delivery system in all low and middle income (LMI) countries. Because EPI has focused on immunization delivery, its major outcome is measured in many countries only as vaccine coverage, not as disease reduction, the real goal of EPI. Monitoring disease reduction requires real-time case-based disease surveillance and appropriate interventions, for which a functional public health infrastructure is needed. If the highest priority for assessing impact of EPI shifts to disease prevention and control from vaccine coverage, the programme may be transformed to one of control of childhood communicable diseases (CCCD), with the potential of expanding the range of diseases of children and adults for control and of integrating all other current vertical (single disease) control efforts with it. EPI provides the essential platform on which CCCD can be built to create a public health infrastructure.

WITHDRAWN: Letter to the Editor.

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Use of predictive markers of HIV disease progression in vaccine trials.

Generating broadly neutralizing antibodies with candidate vaccines has remained an elusive goal. Consequently, vaccine candidates developed have aimed at eliciting cell-mediated immune effector activities (CMI) that could delay disease progression, and maybe also limit secondary transmission, by controlling virus replication. There is considerable discussion about what types of endpoints would constitute definable standardized clinical benefit to the individual that would result in licensure of these candidate vaccines. Identifying biomarkers that can be used as surrogates for clinical endpoints in randomized clinical trials would be useful, because it would shorten studies and reduce costs. Biological markers associated with disease progression and secondary transmission and that may be used as prognosis markers and surrogate endpoints in HIV vaccine trials have emerged from analyses of data from studies on natural history of HIV infection. Extensive literature is cited to support the use of plasma viral load as a primary endpoint for supporting licensure decisions. Overall, a significant result on viral load in a vaccine trial should be considered as a significant breakthrough for vaccines and be aggressively pursued with the caveat that such a result should rapidly be followed by well-defined studies to verify durable virological and immunological vaccine benefit, as well as ultimate clinical benefit. The review also provides perspectives on magnitude of viral load reduction, durability of viral load reduction for reduced progression of HIV disease.

Alterations in the SMARCB1 (INI1) tumor suppressor gene in familial schwannomatosis.

Schwannomatosis is a third major form of neurofibromatosis that has recently been linked to mutations in the SMARCB1 (hSnf5/INI1) tumor suppressor gene. We analyzed the coding region of SMARCB1 by direct sequencing and multiplex ligation-dependent probe amplification (MLPA) in genomic DNA from 19 schwannomatosis kindreds. Microsatellite markers in the SMARCB1 region were developed to determine loss of heterozygosity (LOH) in associated tumors. We detected four alterations in conserved splice acceptor or donor sequences of exons 3, 4 and 6. Two alterations that likely affect splicing were seen in introns 4 and 5. An additional four alterations of unclear pathogenicity were found to segregate on the affected allele in eight families including two non-conservative missense alterations in three families. No constitutional deletions or duplications were detected by MLPA. Nine of 13 tumors examined showed partial LOH of the SMARCB1 region consistent with 'second hits.' Alterations were detected in tumors both with and without somatic NF2 gene changes. These findings support the hypothesis that SMARCB1 is a tumor suppressor for schwannomas in the context of familial disease. Further work is needed to determine its role in other multiple and single tumor syndromes.

Diagnostic criteria for schwannomatosis.

The neurofibromatoses are a diverse group of genetic conditions that share a predisposition to the development of tumors of the nerve sheath. Schwannomatosis is a recently recognized third major form of neurofibromatosis (NF) that causes multiple schwannomas without vestibular tumors diagnostic of NF2. Patients with schwannomatosis represent 2.4 to 5% of all patients requiring schwannoma resection and approximately one third of patients with schwannomatosis have anatomically localized disease with tumors limited to a single limb or segment of spine. Epidemiologic studies suggest that schwannomatosis is as common as NF2, but that familial occurrence is inexplicably rare. Patients with schwannomatosis overwhelmingly present with pain, and pain remains the primary clinical problem and indication for surgery. Diagnostic criteria for schwannomatosis are needed for both clinicians and researchers, but final diagnostic certainly will await the identification of the schwannomatosis locus itself.

Determination of barrier heights and prefactors from protein folding rate data.

We determine both barrier heights and prefactors for protein folding by applying constraints determined from experimental rate measurements to a Kramers theory for folding rate. The theoretical values are required to match the experimental values at two conditions of temperature and denaturant that induce the same stability. Several expressions for the prefactor in the Kramers rate equation are examined: a random energy approximation, a correlated energy approximation, and an approximation using a single Arrhenius activation energy. Barriers and prefactors are generally found to be large as a result of implementing this recipe, i.e., the folding landscape is cooperative and smooth. Interestingly, a prefactor with a single Arrhenius activation energy admits no formal solution.

Protein folding rates correlate with heterogeneity of folding mechanism.

By observing trends in the folding kinetics of experimental 2-state proteins at their transition midpoints, and by observing trends in the barrier heights of numerous simulations of coarse-grained, C(alpha) model Go proteins, we show that folding rates correlate with the degree of heterogeneity in the formation of native contacts. Statistically significant correlations are observed between folding rates and measures of heterogeneity inherent in the native topology, as well as between rates and the variance in the distribution of either experimentally measured or simulated phi values.

Three-body interactions improve the prediction of rate and mechanism in protein folding models.

Here we study the effects of many-body interactions on rate and mechanism in protein folding by using the results of molecular dynamics simulations on numerous coarse-grained Calpha-model single-domain proteins. After adding three-body interactions explicitly as a perturbation to a Go-like Hamiltonian with native pairwise interactions only, we have found (i) a significantly increased correlation with experimental phi values and folding rates, (ii) a stronger correlation of folding rate with contact order, matching the experimental range in rates when the fraction of three-body energy in the native state is approximately 20%, and (iii) a considerably larger amount of three-body energy present in chymotripsin inhibitor than in the other proteins studied.

Development of a cytomegalovirus vaccine: lessons from recent clinical trials.

Cytomegalovirus-caused diseases are preventable. We believe that both neutralising antibodies and cell-mediated immunity are necessary for prevention. Of the CMV proteins, gB and pp65 are the minimum requirements in a vaccine to induced neutralising antibodies and cytotoxic T-lymphocyte (CTL) responses. Immunisation with additional proteins, e.g., gH, gN for neutralising antibodies and IE1exon 4 and pp150 for CTL responses, would strengthen protective immune responses. Approaches to development of a safe and effective cytomegalovirus (CMV) vaccine for the prevention of CMV diseases include: a) a live attenuated vaccine (Towne strain); b) recombinant constructs of the attenuated Towne and the virulent Toledo CMV strains; c) subunit glycoprotein B (gB) adjuvanted with MF59 to induce neutralising antibodies; d) phosphoprotein 65 (pp65) peptide-based vaccines to induce (CTL) for use in therapeutic vaccination; e) canarypox-CMV recombinants, e.g., ALVAC-CMV(gB) and ALVAC-CMV (pp65) to induce neutralising antibodies and CTL responses, respectively; f) DNA plasmids containing the genes for gB and pp65; g) dense bodies containing the key antigens. The attenuated Towne strain, gB/MF59, ALVAC-CMV(gB) and ALVAC-CMV(pp65) approaches have already been tested in clinical trials. The Towne vaccine induced neutralising antibodies and cell-mediated immunity (including CTLs) mitigated CMV disease in seronegative renal transplant recipients and protected against a low-dose virulent CMV challenge in normal volunteers but did not prevent infection in mothers of children excreting CMV. Immunisation with gB/MF59 resulted in high levels of neutralising antibodies in seronegative subjects. ALVAC-CMV(gB) did not induce neutralising antibodies but primed the immune system to a Towne strain challenge, while ALVAC-CMV(pp65) induced long-lasting CTL responses in all originally seronegative volunteers, with CTL precursor frequency similar to naturally seropositive individuals. These results suggest that CMV diseases can be prevented or attenuated and that a vaccine combining ALVAC-CMV(pp65) with gB/MF59 may induce sufficient CTLs and neutralising antibodies to protect against CMV diseases. Meanwhile, other approaches such as DNA peptide and dense body vaccines, should enter Phase I trials. All candidate vaccines will have to demonstrate that immunogenicity provides protection. Combined vaccines containing canarypox (ALVAC) vectors to express CMV-pp65 to induce CTLs and of subunit gB, given together with an appropriate adjuvant to induce neutralising antibodies, should be tested in a target population for the prevention of CMV infection and disease.

Speeding protein folding beyond the G(o) model: how a little frustration sometimes helps.

By perturbing a G(o) model toward a realistic protein Hamiltonian by adding non-native interactions, we find that the folding rate is in general enhanced as ruggedness is initially increased, as long as the protein is sufficiently large and flexible. Eventually, the rate drops rapidly toward zero when ruggedness significantly slows conformational transitions. Energy landscape arguments for thermodynamics and kinetics are coupled with a treatment of non-native collapse to elucidate this effect.