Navigated transcranial magnetic stimulation of the primary somatosensory cortex impairs perceptual processing of tactile temporal discrimination

Previous studies indicate that transcranial magnetic stimulation (TMS) with biphasic pulses applied approximately over the primary somatosensory cortex (S1) suppresses performance in vibrotactile temporal discrimination tasks; these previous results, however, do not allow separating perceptual influence from memory or decision-making. Moreover, earlier studies using external landmarks for directing biphasic TMS pulses to the cortex do not reveal whether the changes in vibrotactile task performance were due to action on S1 or an adjacent area. In the present study, we determined whether the S1 area representing a cutaneous test site is critical for perceptual processing of tactile temporal discrimination. Electrical test pulses were applied to the thenar skin of the hand and the subjects attempted to discriminate single from twin pulses. During discrimination task, monophasic TMS pulses or sham TMS pulses were directed anatomically accurately to the S1 area representing the thenar using magnetic resonance image-guided navigation. The subject's capacity to temporal discrimination was impaired with a decrease in the delay between the TMS pulse and the cutaneous test pulse from 50 to 0 ms. The result indicates that S1 area representing a cutaneous test site is involved in perceptual processing of tactile temporal discrimination.     

Vaccines: could asthma in young children be a preventable disease? ‬‬‬‬‬‬‬

?The long battle with asthma is far from over in developed countries. Its incidence, prevalence, and severity have been increasing for decades. By reducing the risk for asthma, significant healthcare costs can be saved. The desire to create a vaccine that might prevent asthma in young children is attractive and widely considered one of the main goals in translational asthma research. Several vaccination strategies have been tested. These include allergen‐specific immunotherapy, vaccination against infectious pathogens, and modification of cell and cytokine responses. The lack of success in the prevention of asthma in young children lies on the complexity of the disease, which involves many genetic, epigenetic, and environmental interactions. This review provides a summary of current literature and aims to address key questions how to develop vaccines to prevent asthma in young children. ??????????????     

The binding of the small heat-shock protein αB-crystallin to fibrils of α-synuclein is driven by entropic forces

Molecular chaperones are key components of the cellular proteostasis network whose role includes the suppression of the formation and proliferation of pathogenic aggregates associated with neurodegenerative diseases. The molecular principles that allow chaperones to recognize misfolded and aggregated proteins remain, however, incompletely understood. To address this challenge, here we probe the thermodynamics and kinetics of the interactions between chaperones and protein aggregates under native solution conditions using a microfluidic platform. We focus on the binding between amyloid fibrils of α-synuclein, associated with Parkinson’s disease, to the small heat-shock protein αB-crystallin, a chaperone widely involved in the cellular stress response. We find that αB-crystallin binds to α-synuclein fibrils with high nanomolar affinity and that the binding is driven by entropy rather than enthalpy. Measurements of the change in heat capacity indicate significant entropic gain originates from the disassembly of the oligomeric chaperones that function as an entropic buffer system. These results shed light on the functional roles of chaperone oligomerization and show that chaperones are stored as inactive complexes which are capable of releasing active subunits to target aberrant misfolded species.

Molecular chaperones are crucial components of the cellular proteostasis network and are characteristically overexpressed during cell stress (1–4). Their roles involve the suppression of aberrant processes, including misfolding and aggregation of proteins, within the context of the complex flux of protein production and degradation. In addition to guiding nascent proteins toward their native structures following biosynthesis on ribosomes, chaperones are increasingly recognized as inhibitors of key steps in the aberrant conversion of normally soluble proteins into amyloid fibrils, protein aggregates that are associated with a wide range of neurodegenerative diseases (5–8). The overall process that leads to the formation of amyloid fibrils consists of a series of microscopic events, including primary and secondary nucleation and fibril elongation and fragmentation (9). Recent analysis of the kinetics of aggregation of several proteins has revealed that molecular chaperones can inhibit the process of amyloid formation through a variety of different microscopic mechanisms (10). In some cases, molecular chaperones have been found to suppress a single specific microscopic step in the aggregation process. In other cases, they have been shown to affect more than one type of aggregation event (7, 8, 11, 12). The modulation of the different molecular steps of protein aggregation is mediated by the binding of chaperones to misfolded protein monomers and various aggregates (11, 13, 14). For a comprehensive understanding of such inhibition processes it is therefore crucial to elucidate the thermodynamic and kinetic determinants of the binding of chaperones to different species populated during amyloid formation.A prevalent group of molecular chaperones that inhibit amyloid formation are the small heat-shock proteins (sHsps), including the vertebrate αB-crystallin (αB-c). The structure of αB-c is a conserved α-crystallin domain with a β-sheet structure, flanked by a hydrophobic N-terminal region and a polar C-terminal tail, both structurally flexible and mutually different (15). Similar to other sHsps in solution, αB-c exists in a polydisperse oligomeric state characterized by dynamic subunit exchange leading to oligomers with 10 to 50 subunits and molecular weights from 300 to 1,000 kDa (16, 17). αB-c has been shown to inhibit the overall amyloid formation process of α-synuclein (α-syn), a protein closely associated with the onset and progression of Parkinson’s disease (18). The mechanism of inhibition has been shown to originate from interactions of the chaperone with aggregated forms of α-syn, ranging from oligomers to mature amyloid fibrils, rather than with α-syn monomers (19, 20). In particular, it has been demonstrated that αB-c binds to α-syn fibrils and inhibits their elongation in solution, thus suppressing the toxicity associated with α-syn aggregation in cells (13, 21).The mechanistic importance of the interactions of αB-c with protein aggregates raises the key question of how chaperones recognize misfolded and aggregated proteins among the diverse ensemble of native states. Elucidating the binding interactions between these proteins poses fundamental challenges that originate from the heterogeneity and dynamic nature of the systems. Both the chaperone and aggregate populations are polydisperse, and the large difference in size between relatively small chaperones and high-molecular-weight client protein aggregates make interactions between them difficult to access with conventional biophysical techniques designed to probe interactions between individual biomolecules (22, 23). We have addressed these limitations using a microfluidic platform to characterize the binding (24). By exploiting the different diffusion coefficients of bound and unbound chaperones we have shown that it is possible to quantify the thermodynamics and the kinetics of binding on the time scale of minutes, where the spatial variation in concentration along the device has a negligible effect on the kinetics due to the short measurement times (24, 25). Here, we apply this approach to identify the intermolecular interactions underlying the recognition of α-syn amyloid fibrils by αB-c and to characterize the energetic trade-off during this binding process in a quantitative manner.     

Seshat: A Web service for accurate annotation,validation, and analysis of TP53 variants generated by conventional and next‐generation sequencing

Accurate annotation of genomic variants in human diseases is essential to allow personalized medicine. Assessment of somatic and germline TP53 alterations has now reached the clinic and is required in several circumstances such as the identification of the most effective cancer therapy for patients with chronic lymphocytic leukemia (CLL). Here, we present Seshat, a Web service for annotating TP53 information derived from sequencing data. A flexible framework allows the use of standard file formats such as Mutation Annotation Format (MAF) or Variant Call Format (VCF), as well as common TXT files. Seshat performs accurate variant annotations using the Human Genome Variation Society (HGVS) nomenclature and the stable TP53 genomic reference provided by the Locus Reference Genomic (LRG). In addition, using the 2017 release of the UMD_TP53 database, Seshat provides multiple statistical information for each TP53 variant including database frequency, functional activity, or pathogenicity. The information is delivered in standardized output tables that minimize errors and facilitate comparison of mutational data across studies. Seshat is a beneficial tool to interpret the ever‐growing TP53 sequencing data generated by multiple sequencing platforms and it is freely available via the TP53 Website, http://p53.fr or directly at http://vps338341.ovh.net/ .     

Photodynamic ablation of lymphatic vessels and intralymphatic cancer cells prevents metastasis

The dissemination of tumor cells to sites far from the primary tumor (metastasis) is the principal cause of death in cancer patients. Tumor-associated lymphatic vessels are a key conduit for metastatic tumor cells, which typically first colonize the lymph nodes. Although the primary tumor and affected lymph nodes can be removed during surgery, tumor cells inside lymphatic vessels are left behind. Here, we show that in-transit tumor cells inside lymphatic vessels in mice bearing mouse melanomas or human lung tumors give rise to metastases. Using photodynamic therapy with the benzoporphyrin derivative verteporfin, we selectively destroyed lymphatic vessels in mice and pigs. Destruction of tumor-associated lymphatic vessels also eradicated intralymphatic tumor cells and prevented metastasis of mouse melanoma cells and subsequent relapse. Photodynamic therapy, when combined with anti-lymphangiogenic therapy, prevented further tumor invasion of lymphatic vessels. These findings highlight the potential of targeting in-transit tumor cells in patients.     

Dynamics and Rate‐Dependence of the Spatial Angle between Ventricular Depolarization and Repolarization Wave Fronts during Exercise ECG

Background: QRS/T angle and the cosine of the angle between QRS and T‐wave vectors (TCRT), measured from standard 12‐lead electrocardiogram (ECG), have been used in risk stratification of patients. This study assessed the possible rate dependence of these variables during exercise ECG in healthy subjects. Methods: Forty healthy volunteers, 20 men and 20 women, aged 34.6 ± 3.4, underwent an exercise ECG testing. Twelve‐lead ECG was recorded from each test subject and the spatial QRS/T angle and TCRT were automatically analyzed in a beat‐to‐beat manner with custom‐made software. The individual TCRT/RR and QRST/RR patterns were fitted with seven different regression models, including a linear model and six nonlinear models. Results: TCRT and QRS/T angle showed a significant rate dependence, with decreased values at higher heart rates (HR). In individual subjects, the second‐degree polynomic model was the best regression model for TCRT/RR and QRST/RR slopes. It provided the best fit for both exercise and recovery. The overall TCRT/RR and QRST/RR slopes were similar between men and women during exercise and recovery. However, women had predominantly higher TCRT and QRS/T values. With respect to time, the dynamics of TCRT differed significantly between men and women; with a steeper exercise slope in women (women, ?0.04/min vs ?0.02/min in men, P < 0.0001). In addition, evident hysteresis was observed in the TCRT/RR slopes; with higher TCRT values during exercise. Conclusions: The individual patterns of TCRT and QRS/T angle are affected by HR and gender. Delayed rate adaptation creates hysteresis in the TCRT/RR slopes. Ann Noninvasive Electrocardiol 2010;15(3):264–275     

Surgical staging, treatment, and follow-up of borderline tumors in different hospital categories: a prospective nationwide survey in Finland

BACKGROUND: Surgical treatment and staging of ovarian borderline tumors have been reported to be often suboptimal and differ considerably. We evaluated the extent of surgical treatment of these tumors in different hospital categories. MATERIAL AND METHODS: A prospective survey performed in 1999 included 65 patients operated on for borderline ovarian tumors and covered 78% of such patients reported to the Finnish Cancer Registry. Detailed information of demographic data and surgical treatment was reported by the responsible physicians using a special questionnaire after confirmation of histopathology. RESULTS: Fifty-eight patients (89%) had stage I tumor, only two patients (3%) had stage II disease and five patients (8%) had stage III disease with peritoneal implants. The majority of the patients underwent bilateral salpingo-oophorectomy (66%) and hysterectomy (58%). Unilateral salpingo-oophorectomy was performed for 21 (32%) and omentectomy for 22 (34%) patients. Ten out of the 16 women under 40 years of age had fertility-sparing surgery. Peritoneal biopsies were taken in 16 (25%) women and lymphadenectomy was performed for 9 (14%) patients with clinical suspicion of invasive ovarian carcinoma. Frozen section was taken in half of the patients and the histology remained the same in 72% of the final pathology reports. No clear differences of the extent of surgical treatment were detected between different hospital categories. Overall cumulative 5-year relative survival rate was 96%. CONCLUSIONS: Bilateral salpingo-oophorectomy and hysterectomy was performed for the majority of patients with borderline ovarian tumor. More attention should be paid to adequate staging of borderline tumors in all hospital categories.     

Prospects for peptide-based immunotherapy for dog allergy

PURPOSE OF REVIEW: Tolerance to ubiquitous environmental substances, allergens, can be accomplished with specific immunotherapy. Conducting therapy with allergen peptides helps to avoid immediate allergic reactions. Dogs are a source of important indoor allergens, which necessitates the development of effective modes of therapy against the allergy they cause. RECENT FINDINGS: The human T-cell epitopes of the major dog allergen Can f 1 were determined recently. They were found to be distributed in seven epitope regions along the molecule. For the peptide immunotherapy of dog allergy, using a pool of seven peptides, one from each of the epitope regions of Can f 1, seems at present to be the best approach. As Can f 1 is not as immunodominant as the main allergens of some other mammals, it remains to be seen whether peptides from other dog allergens should be included in the pool. SUMMARY: The use of a pool of seven peptides from the T-cell epitope regions of Can f 1 is likely to be feasible for treating dog allergy in a great majority of Caucasian populations. In the future, patient-tailored preparations of variants of the T-cell epitope-containing peptides may offer a way to enhance the efficacy of peptide-based immunotherapy.     

Repeated bout effect on the cytoskeletal proteins titin,desmin, and dystrophin in rat skeletal muscle

The aim of this study was to evaluate the effect of repeated bouts of exercise on the cytoskeletal proteins titin, desmin, and dystrophin. Rats were made to run downhill for 90 min 1 or 5 times separated by 14 days. Samples were taken from quadriceps femoris muscle 3, 48, 96 h and 50 days after the last exercise session and detected by quantitative PCR, histochemical stainings, and western blot analyses. Histopathological changes in titin, desmin, and dystophin stainings, an increase in β-glucuronidase activity (a quantitative indicator of muscle damage), a significant decrease in the relative content of dystrophin, and intramyocellular Evans blue staining (signs of changes in sarcolemmal permeability) observed after one exercise session were attenuated after 5 exercise sessions. Titin mRNA level was not increased after the initial exercise session but was increased after the fifth session. Desmin and dystrophin mRNA levels were increased after the first and fifth sessions with desmin showing a smaller increase after the fifth session compared to the first session. Prior exercise induces adaptation that protects the sarcolemma as well as subsarcolemmal, intermediate filament, and sarcomeric proteins against disruption. Changes in mRNA levels of titin, desmin, and dystophin after an acute exercise session obviously reflect the need of these proteins in the repair process following damage. After five sessions increase in mRNA of studied proteins suggest a strong involvement in continuing adaptation to the increased exercise.     

Allergen‐specific naïve and memory CD4+ T cells exhibit functional and phenotypic differences between individuals with or without allergy

Although allergen‐specific CD4⁺ T cells are detectable in the peripheral blood of both individuals with or without allergy, their frequencies and phenotypes within the memory as well as naïve repertoires are incompletely known. Here, we analyzed the DRB1*0401‐restricted responses of peripheral blood‐derived memory (CD4⁺CD45RO⁺) and naïve (CD4⁺CD45RA⁺) T cells from subjects with or without allergy against the immunodominant epitope of the major cow dander allergen Bos d 2 by HLA class II tetramers in vitro. The frequency of Bos d 2_127–142‐specific memory T cells in the peripheral blood‐derived cultures appeared to be higher in subjects with allergy than those without, whereas naïve Bos d 2_127–142‐specific T cells were detectable in the cultures of both groups at nearly the same frequency. Surprisingly, the TCR avidity of Bos d 2_127–142‐specific T cells of naïve origin, as assessed by the intensity of HLA class II tetramer staining, was found to be higher in individuals with allergy. Upon restimulation, long‐term Bos d 2_127–142‐specific T‐cell lines generated from both memory and naïve T‐cell pools from individuals with allergy proliferated more strongly, produced more IL‐4 and IL‐10, and expressed higher levels of CD25 but lower levels of CXCR3 than the T‐cell lines from individuals without allergy, demonstrating differences also at the functional level. Collectively, our current results suggest that not only the memory but also the naïve allergen‐specific T‐cell repertoires differ between individuals with or without allergy.