158 research outputs found

    Regulation of Intraflagellar Transport in the sensory cilia of Caenorhabditis Elegans

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    Cilia zijn kleine uitstulpingen op het celoppervlakte. Ze zijn belangrijk bij de beweging van cellen, zoals bijvoorbeeld bij sperma cellen, maar hebben daarnaast ook een sensorische functie. Wij hebben voor ons cilia onderzoek gekozen voor het model organisme Caenorhabditis elegans, aangezien cilia zeer geconserveerd zijn tijdens de evolutie en defecten in cilia niet lethaal zijn in dit organisme in tegenstelling tot vele andere dieren. Alle cilia hebben een vergelijkbare opbouw. Het bestaat uit verschillende buisvormige filamenten omgeven door het celmembraan. Het begin van de cilia wordt de transitie zone genoemd, waarna het eerste deel van de cilia, het middel segment en het uitMany environmental signals are detected by specialized sensory neurons, which have cilia extending from the cell surface as long appendices and exposed to the environment. Cilia consist of a microtubular axonemal core surrounded by a membrane and are anchored in the cell by the basal body. The end of the basal body and the beginning of the axoneme are called the transition zone. Since cilia do not have the capacity to synthesize proteins, all components, both structural and signaling molecules, need to be transported into and out of the cilia. This is probably achieved by a process called intraflagellar transport (IFT) and is driven by three motors in Caenorhabditis elegans. Two motors, kinesin-II and OSM-3 kinesin, are used for anterograde transport from the base of the cilium to the distal tip. Both these kinesin motor complexes are involved in the transport in the first 4 µm of the cilium, called the middle segment, whereas only OSM-3 kinesin is required for the transport in the last 2,5 µm of the cilium until the distal tip, called the distal segment. Retrograde transport from the distal tip back to the basal body is dependent on the dynein motor complex. IFT is not only responsible for the transport of structural components but recently three signalling molecules have been described to be transported in the cilia i.e. OSM-9, a transient receptor potential vanilloid channel involved in sensory signal transduction, a PKD associated protein called qilin and Smoothened, a plasma membrane protein involved in hedgehog signaling

    De digitale PAL-decoder

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    A chloride-inducible acid resistance mechanism in Lactococcus lactis and its regulation

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    Previously, a promoter was identified in Lactococcus lactis that is specifically induced by chloride. Here, we describe the nucleotide sequence and functional analysis of two genes transcribed from this promoter, gadC and gadB. GadC is homologous to putative glutamate-γ-aminobutyrate antiporters of Escherichia coli and Shigella flexneri and contains 12 putative membrane-spanning domains. GadB shows similarity to glutamate decarboxylases. A L. lactis gadB mutant and a strain that is unable to express both gadB and gadC was more sensitive to low pH than the wild type when NaCl and glutamate were present. Expression of gadCB in L. lactis in the presence of chloride was increased when the culture pH was allowed to decrease to low levels by omitting buffer from the medium, while glutamate also stimulated gadCB expression. Apparently, these genes encode a glutamate-dependent acid resistance mechanism of L. lactis that is optimally active under conditions in which it is needed to maintain viability. Immediately upstream of the chloride-dependent gadCB promoter Pgad, a third gene encodes a protein (GadR) that is homologous to the activator Rgg from Streptococcus gordonii. gadR expression is chloride and glutamate independent. A gadR mutant did not produce the 3 kb gadCB mRNA that is found in wild-type cells in the presence of NaCl, indicating that GadR is an activator of the gadCB operon.

    The Value of Tracking Data on the Behavior of Patients Who Have Undergone Bariatric Surgery:Explorative Study

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    Background: To maintain the benefits of a bariatric procedure, patients have to change their lifestyle permanently. This happens within a context of coresponsibilities of health care professionals and their social support system. However, most interventions are focused on the patient as an individual. In this explorative pilot study, behavioral, contextual, and experiential data were gathered to obtain insight on coresponsibility. Objective: The aim of this study is to explore the use of trackers by patients who have undergone bariatric surgery in a data-enabled design approach. Methods: Behavioral and contextual data on the households of patients who have undergone bariatric surgery were explored using a smartphone with an interactive user interface (UI), weight scale, activity bracelet, smart socket, accelerometer motion sensor, and event button to find examples of opportunities for future interventions. Results: A total of 6 households were monitored. Approximately 483,000 data points were collected, and the participants engaged in 1483 conversations with the system. Examples were found using different combinations of data types, which provided the obesity team a better understanding of patient behaviors and their support system, such as a referral to a family coach instead of a dietician. Another finding regarding the partners was, for example, that the conversational UI system facilitated discussion about the support structure by asking for awareness. Conclusions: An intelligent system using a combination of quantitative data gathered by data tracking products in the home environment and qualitative data gathered by app-enhanced short conversations, as well as face-to-face interviews, is useful for an improved understanding of coresponsibilities in the households of patients who have undergone bariatric surgery. The examples found in this explorative study so far encourage research in this field.</p

    The Value of Tracking Data on the Behavior of Patients Who Have Undergone Bariatric Surgery:Explorative Study

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    Background: To maintain the benefits of a bariatric procedure, patients have to change their lifestyle permanently. This happens within a context of coresponsibilities of health care professionals and their social support system. However, most interventions are focused on the patient as an individual. In this explorative pilot study, behavioral, contextual, and experiential data were gathered to obtain insight on coresponsibility. Objective: The aim of this study is to explore the use of trackers by patients who have undergone bariatric surgery in a data-enabled design approach. Methods: Behavioral and contextual data on the households of patients who have undergone bariatric surgery were explored using a smartphone with an interactive user interface (UI), weight scale, activity bracelet, smart socket, accelerometer motion sensor, and event button to find examples of opportunities for future interventions. Results: A total of 6 households were monitored. Approximately 483,000 data points were collected, and the participants engaged in 1483 conversations with the system. Examples were found using different combinations of data types, which provided the obesity team a better understanding of patient behaviors and their support system, such as a referral to a family coach instead of a dietician. Another finding regarding the partners was, for example, that the conversational UI system facilitated discussion about the support structure by asking for awareness. Conclusions: An intelligent system using a combination of quantitative data gathered by data tracking products in the home environment and qualitative data gathered by app-enhanced short conversations, as well as face-to-face interviews, is useful for an improved understanding of coresponsibilities in the households of patients who have undergone bariatric surgery. The examples found in this explorative study so far encourage research in this field.</p

    Detection of immune-complex-dissociated nonstructural-1 antigen in patients with acute dengue virus infections

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    Accurate and timely diagnosis of dengue virus (DEN) infections is essential for the differential diagnosis of patients with febrile illness and hemorrhagic fever. In the present study, the diagnostic value of a newly developed immune-complex dissociated nonstructural-1 (NS-1) antigen dot blot immunoassay (DBI) was compared to a commercially available DEN antigen detection kit (denKEY Blue kit; Globio Co., Beverly, Mass.) and a reverse transcription-PCR (RT-PCR) kit. Serial serum or plasma samples (n = 181) obtained from 55 acute DEN-infected patients were used. In samples obtained from 32 of these 55 DEN-infected patients, viral RNA could be detected by RT-PCR. DEN antigen was detected in only 10 of these 55 patient samples by using the denKEY kit. When these samples were treated with acid to release the immune-complex-associated NS-1 antigen for detection by DBI, 43 of these 55 patients were found to be positive for DEN NS-1 antigen. In nondiss

    Multi-level analyses of spatial and temporal determinants for dengue infection

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    BACKGROUND: Dengue is a mosquito-borne viral infection that is now endemic in most tropical countries. In Thailand, dengue fever/dengue hemorrhagic fever is a leading cause of hospitalization and death among children. A longitudinal study among 1750 people in two rural and one urban sites in northern Thailand from 2001 to 2003 studied spatial and temporal determinants for recent dengue infection at three levels (time, individual and household). METHODS: Determinants for dengue infection were measured by questionnaire, land-cover maps and GIS. IgM antibodies against dengue were detected by ELISA. Three-level multi-level analysis was used to study the risk determinants of recent dengue infection. RESULTS: Rates of recent dengue infection varied substantially in time from 4 to 30%, peaking in 2002. Determinants for recent dengue infection differed per site. Spatial clustering was observed, demonstrating variation in local infection patterns. Most of the variation in recent dengue infection was explained at the time-period level. Location of a person and the environment around the house (including irrigated fields and orchards) were important determinants for recent dengue infection. CONCLUSION: We showed the focal nature of asymptomatic dengue infections. The great variation of determinants for recent dengue infection in space and time should be taken into account when designing local dengue control programs

    The relation between the degree of synaesthesia, autistic traits, and local/global visual perception

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    In individuals with synaesthesia specific sensory stimulation leads to unusual concurrent perceptions in the same or a different modality. Recent studies have demonstrated a high co-occurrence between synaesthesia and autism spectrum disorder (ASD), a condition also characterized by altered perception. A potentially shared characteristic of synaesthesia and ASD is a bias towards local (detail-focussed) perception. We investigated whether a bias towards local perception is indeed shared between synaesthesia and ASD. In a neurotypical population, we studied the relation between the degree of autistic traits (measured by the AQ) and the degree of grapheme-colour synaesthesia (measured by a consistency task), as well as whether both are related to a local bias in tasks assessing local/global visual perception. A positive correlation between total AQ scores and the degree of synaesthesia was found. Our study extends previous studies that found a high ASD-synaesthesia co-occurrence in clinical populations. Consistent with the hypothesized local perceptual bias in ASD, scores on the AQ-attention to detail subscale were related to increased performance on an Embedded Figures Task (EFT), and we found evidence for a relation to reduced susceptibility to visual illusions. We found no relation between autistic traits and local visual perception in a motion coherence task (MCT). Also, no relation between synaesthesia and local visual perception was found, although a reduced susceptibility to visual illusions resembled the results obtained for AQ-atttention to detail subscale. A suggested explanation for the absence of a relationship between the degree of synaesthesia and a local bias is that a possible local bias might be more pronounced in supra-threshold synaesthetes (compared to neurotypicals)
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