Auflistung nach Autor:in "Bosch, Lars ten"

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    Cold atmospheric pressure plasma as insecticide-free pediculosis treatment approach
    (2017) Bosch, Lars ten; Habedank, Birgit; Viöl, Wolfgang
    Treatment failures after the use of pediculicides, e.g. by insecticide-resistant head lice populations, led us to the development of a non-toxic, insecticide-free and ecologically benign alternative, based on a physical principle. This new treatment approach is known as cold atmospheric plasma (CAP). CAP is used e.g. in the newly developed field of plasma medicine such as treatment of diabetic wounds or within oncology. A comb-like device build upon the principles of a dielectric barrier discharge was developed. We investigated the efficacy of the plasma comb against lice and eggs of Pediculus humanus humanus on human hair strands in controlled laboratory conditions. Adults, juvenile lice and eggs of the rabbit-adapted laboratory strain of the German Environment Agency on human natural hair strands were combed with the plasma comb at ˙1 s/cm for one transition only. The treated lice were observed up to 48 h, eggs until 15 days after egg deposition. Furthermore, the mortality of adult lice was examined under ideal conditions by exposing single lice directly to the plasma resulting in a mortality of 100% after 24 h. Immediately after the treatment some lice showed an abnormal movement behaviour. Within the first hour a blood penetration from the gut in the haemocoel was visible in some lice, already. Many dead lice showed signs of body deformation. The presumed modes of action of the plasma comb are the combination of fast electric fields combined with reactive species, both generated within the discharge volume leading apparently to membrane damages inside the lice. Quelle: http://www.uibcongres.org/
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    Cold atmospheric pressure plasma comb - a physical approach for pediculosis treatment
    (2018) Bosch, Lars ten; Habedank, Birgit; Siebert, Dominik
    Pediculosis, that is the infestation of humans with Pediculus humanus capitis (head lice), poses a worldwide problem that is as old as mankind itself. Over the centuries, man has developed a variety of remedies, all of which have ultimately culminated in the use of chemical agents. Some of these remedies are known to produce successful results. A large portion of the effective remedies used to kill lice and their eggs contain insecticides, but there is an increasing number of reports of head lice populations revealing an increased resistance. This study presents an alternative treatment approach, the efficacy of which is based on physical effects. Cold atmospheric pressure plasmas have successfully shown their formidably wide application range within the field of plasma medicine. This study presents a plasma device in its current stage of development that is engineered as a consumer product to enable an alternative physical and insecticide-free option for the treatment of pediculosis. An efficacy study concerning different developmental stages of P. humanus humanus is presented. P. humanus humanus was chosen as a substitute test organism for P. humanus capitis due to possible laboratory rearing and high anatomic similarity. The study shows how a single stroke of the plasma device over a hair strand (approximately 22 cm in length with a weight of 1.5 g) led to mortality rates of 68.3% (50.0; 79.7) (95% CI) in the juvenile test group, a mortality rate of approx. 67.7% (54.9; 78.8) (95% CI) in the female test group, and approx. 46.7% (28.3; 65.7) (95% CI) in the male test group. When single eggs were introduced directly into the plasma for approx. 1 s, younger eggs (0-2 d) showed a higher mortality of 66.7% (42.7; 82.7) than the older (4-6 d) eggs, with 16.7% (5.6; 34.7) (CI). Furthermore, the results of a risk assessment of the device are described. The article concludes with necessary handling instructions as well as further developmental steps, derived from the results of the efficacy and the risk assessment study. Quelle: https://www.mdpi.com
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    Light sheet fluorescence microscopy for the investigation of blood-sucking arthropods dyed via artificial membrane feeding
    (2022) Bosch, Lars ten; Candeo, Alessia; Bassi, Andrea; Valentini, Gianluca; Habedank, Birgit; Gerhard, Christoph
    Physical methods to control pest arthropods are increasing in importance, but detailed knowledge of the effects of some of these methods on the target organisms is lacking. The aim of this study was to use light sheet fluorescence microscopy (LSFM) in anatomical studies of blood-sucking arthropods in vivo to assess the suitability of this method to investigate the morphological structures of arthropods and changes in these structures over time, using the human louse Pediculus humanus (Phthiraptera: Pediculidae) as sample organism. Plasma treatment was used as an example of a procedure employed to control arthropods. The lice were prepared using an artificial membrane feeding method involving the ingestion of human blood alone and human blood with an added fluorescent dye in vitro. It was shown that such staining leads to a notable enhancement of the imaging contrast with respect to unstained whole lice and internal organs that can normally not be viewed by transmission microscopy but which become visible by this approach. Some lice were subjected to plasma treatment to inflict damage to the organisms, which were then compared to untreated lice. Using LSFM, a change in morphology due to plasma treatment was observed. These results demonstrate that fluorescence staining coupled with LSFM represents a powerful and straightforward method enabling the investigation of the morphology - including anatomy - of blood-sucking lice and other arthropods. © The Author(s) 2022.