@article{WorkuStichDaugschiesetal.2015,
  author    = {Worku, Netsanet and Stich, August and Daugschies, Arwid and Wenzel, Iris and Kurz, Randy and Thieme, Rene and Kurz, Susanne and Birkenmeier, Gerd},
  title     = {Ethyl Pyruvate Emerges as a Safe and Fast Acting Agent against Trypanosoma brucei by Targeting Pyruvate Kinase Activity},
  series = {PLoS ONE},
  volume    = {10},
  journal   = {PLoS ONE},
  number    = {9},
  doi       = {10.1371/journal.pone.0137353},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-150002},
  pages     = {e0137353},
  year      = {2015},
  abstract  = {Background Human African Trypanosomiasis (HAT) also called sleeping sickness is an infectious disease in humans caused by an extracellular protozoan parasite. The disease, if left untreated, results in 100\% mortality. Currently available drugs are full of severe drawbacks and fail to escape the fast development of trypanosoma resistance. Due to similarities in cell metabolism between cancerous tumors and trypanosoma cells, some of the current registered drugs against HAT have also been tested in cancer chemotherapy. Here we demonstrate for the first time that the simple ester, ethyl pyruvate, comprises such properties. Results The current study covers the efficacy and corresponding target evaluation of ethyl pyruvate on T. brucei cell lines using a combination of biochemical techniques including cell proliferation assays, enzyme kinetics, phasecontrast microscopic video imaging and ex vivo toxicity tests. We have shown that ethyl pyruvate effectively kills trypanosomes most probably by net ATP depletion through inhibition of pyruvate kinase (Ki = 3.0\(\pm\)0.29 mM). The potential of ethyl pyruvate as a trypanocidal compound is also strengthened by its fast acting property, killing cells within three hours post exposure. This has been demonstrated using video imaging of live cells as well as concentration and time dependency experiments. Most importantly, ethyl pyruvate produces minimal side effects in human red cells and is known to easily cross the blood-brain-barrier. This makes it a promising candidate for effective treatment of the two clinical stages of sleeping sickness. Trypanosome drug-resistance tests indicate irreversible cell death and a low incidence of resistance development under experimental conditions. Conclusion Our results present ethyl pyruvate as a safe and fast acting trypanocidal compound and show that it inhibits the enzyme pyruvate kinase. Competitive inhibition of this enzyme was found to cause ATP depletion and cell death. Due to its ability to easily cross the blood-brain-barrier, ethyl pyruvate could be considered as new candidate agent to treat the hemo-lymphatic as well as neurological stages of sleeping sickness.},
  language  = {en}
}
@article{UnnewehrStich2015,
  author    = {Unnewehr, Markus and Stich, August},
  title     = {Fighting Hepatitis B in North Korea: Feasibility of a Bi-modal Prevention Strategy},
  series = {Journal of Korean Medical Science},
  volume    = {30},
  journal   = {Journal of Korean Medical Science},
  doi       = {10.3346/jkms.2015.30.11.1584},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-138773},
  pages     = {1584-1588},
  year      = {2015},
  abstract  = {In North Korea, the prevalence of hepatitis B is high due to natural factors, gaps in vaccination, and the lack of antiviral treatment. Aid projects are urgently needed, however impeded by North Korea's political and economical situation and isolation. The feasibility of a joint North Korean and German humanitarian hepatitis B prevention program was assessed. Part 1: Hepatitis B vaccination catch-up campaign. Part 2: Implementation of endoscopic ligation of esophageal varices (EVL) by trainings in Germany and North Korea. By vaccinating 7 million children between 2010 and 2012, the hepatitis B vaccination gap was closed. Coverage of 99.23\% was reached. A total of 11 hepatitis B-induced liver cirrhosis patients (mean age 41.1 yr) with severe esophageal varices and previous bleedings were successfully treated by EVL without major complications. A clinical standard operating procedure, a feedback system and a follow-up plan were developed. The bi-modal preventive strategy was implemented successfully. Parts of the project can serve as an example for other low-income countries, however its general transferability is limited due to the special circumstances in North Korea.},
  language  = {en}
}
@phdthesis{Sun2015,
  author    = {Sun, Ping},
  title     = {Alzheimer`s disease and brain insulin resistance: The diabetes inducing drug streptozotocin diminishes adult neurogenesis in the rat hippocampus - an in vivo and in vitro study},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119252},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Alzheimer's disease (AD) is the most prevalent neurodegenerative disease of the brain, which is characterized by a progressive loss of memory and spatial orientation. Only less than 5-10\% of AD sufferers are familial cases due to genetic mutations in the amyloid precursor protein (APP) gene or presenilin (PS) 1 and 2 genes. The cause of sporadic AD (sAD) which covers > 95\% of AD patients is still unknown. Current research found interactions between aging, diabetes and cognitive decline including dementia in general and in AD in particular. Disturbances of brain glucose uptake, glucose tolerance and utilization and impairment of the insulin/insulin receptor (IR) signaling cascade are thought to be key targets for the development of sAD. In the brain of AD patients, neural plasticity is impaired indicated by synaptic and neuronal loss. Adult neurogenesis (AN), the generation of functional neurons in the adult brain, may be able to restore neurological function deficits through the integration of newborn neurons into existing neural networks. The dentate gyrus of the hippocampus is one out of few brain regions where life-long AN exists. However, there is a big controversy in literature regarding the involvement of AN in AD pathology. Most animal studies used transgenic mice based on the Amyloid ß (Aß) hypothesis which primarily act as models for the familial form of AD. Findings from human post mortem AN studies were also inconstistent. In this thesis, we focused on the possible involvement of AN in the pathogenesis of the sporadic form of AD. Streptozotocin intracerebroventricularily (STZ icv) treated rats, which develop an insulin-resistant brain state and learning and memory deficits preceding Aß pathology act as an appropriate animal model for sAD. We used STZ treatment for both parts of my work, for the in vivo and in vitro study. In the first part of my thesis, my coworkers and I investigated STZ icv treatment effects on different stages of AN in an in vivo approach. Even if STZ icv treatment does not seem to considerably influence stem cell proliferation over a short-term (1 month after STZ icv treatment) as well as in a long-term (3 months after STZ icv treatment) period, it results in significantly less immature and newborn mature neurons 3 months after STZ icv treatment. This reduction detected after 3 months was specific for the septal hippocampus, discussed to be important for spatial learning. Subsequently we performed co-localization studies with antibodies detecting BrdU (applied appr. 27 days before sacrifice) and cell-type specific markers such as NeuN, and GFAP, we found that STZ treatment does not affect the differentiation fate of newly generated cells. Phenotype analysis of BrdU-positive cells in the hilus and molecular layer revealed that some of the BrdU-positive cells are newborn oligodendrocytes but not newborn microglia. In the second part of my thesis I worked with cultured neural stem cells (NSCs) isolated from the adult rat hippocampus to reveal STZ effects on the proliferation of of NSCs, and on the survival and differentiation of their progeny. Furthermore, this in vitro approach enabled me to study cellular mechanisms underlying the observed impaired neurogenesis in the hippocampus of STZ-treated rats. In contrast to our findings of the STZ icv in vivo study we revealed that STZ supplied with the cell culture medium inhibits the proliferation of NSCs in a dose-dependent and time-dependent manner. Moreover, performing immunofluorescence studies with antibodies detecting cell-type specific markers after triggering NSCs to differentiate, we could show that STZ treatment affects the number of newly generated neurons but not of astrocytes. Analyzing newborn cells starting to differentiate and migrate I was able to demonstrate that STZ has no effect on the migration of newborn cells. Trying to reveal cellular mechanisms underlying the negative influence of STZ on hippocampal AN, we performed qRT-PCR and immunofluorescence staining and thus could show that in NSCs the expression of glucose transporter (GLUT)3 mRNA as well as IR and GLUT3 protein levels are reduced after STZ treatment. Therefore, the inhibition of the proliferation of NSCs may be (at least partially) caused by these two molecules. Interestingly, the effect of STZ on differentiating cells was shown to be different, as IR protein expression was not significantly changed but GLUT3 protein levels were decreased in consequence of STZ treatment. In summary, this project delivered further insights into the interrelation between AN the sporadic form of sAD and thus provides a basis of new therapeutic approaches in sAD treatment through intervening AN. Discrepancies between the results of the two parts of my thesis, the in vivo and in vitro part, were certainly caused to a certain extent by the missing microenvironment in the in vitro approach with cultured NSCs. Future studies e.g. using co-culture systems could at least minimize the effect of a missing natural microenvironment of cultured NSCs, so that the use of an in vitro approach for the investigation of STZ treatment underlying cellular mechanisms can be improved.},
  subject      = {Alzheimerkrankheit},
  language  = {en}
}
@article{MuellerStoetterKalluvyaetal.2015,
  author    = {Mueller, A. and Stoetter, L. and Kalluvya, S. and Stich, A. and Majinge, C. and Weissbrich, B. and Kasang, C.},
  title     = {Prevalence of hepatitis B virus infection among health care workers in a tertiary hospital in Tanzania},
  series = {BMC Infectious Diseases},
  volume    = {15},
  journal   = {BMC Infectious Diseases},
  number    = {386},
  doi       = {10.1186/s12879-015-1129-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-141786},
  year      = {2015},
  abstract  = {Background: Sub-Saharan Africa has a high prevalence of hepatitis B virus (HBV) infections. Health care workers (HCWs) are at high risk of contracting HBV infection through their occupation. Vaccination of HCWs against HBV is standard practice in many countries, but is often not implemented in resource-poor settings. We aimed with this cross-sectional study to determine HBV prevalence, HCW vaccination status, and the risk factors for HCWs contracting HBV infection in Tanzania. Methods: We enrolled 600 HCWs from a tertiary Tanzanian hospital. Their demographics, medical histories, HBV vaccination details and risk factors for contracting blood-borne infections were collected using a standardized questionnaire. Serum samples were tested for HBV and hepatitis C virus (HCV) markers by ELISA techniques, PCR and an anti-HBs rapid test. HCWs were divided in two subgroups: those at risk of contracting HBV (rHCW 79.2 \%) via exposure to potentially infectious materials, and those considered not at risk of contracting HBV (nrHCW, 20.8 \%). Results: The overall prevalence of chronic HBV infection (HBsAg+, anti-HBc+, anti-HBs-) was 7.0 \% (42/598). Chronic HBV infection was found in 7.4 \% of rHCW versus 5.6 \% of nrHCW(p-value = 0.484). HCWs susceptible to HBV (HBsAg-, anti-HBc-, anti-HBs-) comprised 31.3 \%. HBV immunity achieved either by healed HBV infection (HBsAg-, anti-HBc+, anti-HBs+) or by vaccination (HBsAg-, anti-HBc-, anti-HBs+) comprised 36.5 \% and 20.2 \%, respectively. 4.8 \% of participants had indeterminate results (HBsAg-, anti-HBc+, anti-HBc-IgM-, anti-HBs-). Only 77.1 \% of HCWs who received a full vaccination course had an anti-HBs titer > 10 ml/U. An anti-HBs point-of-care test was 80.7 \% sensitive and 96.9 \% specific. There was a significantly higher risk for contracting HBV (anti-HBc+) among those HCW at occupational risk (rHCW) of older age (odds ratios (OR) in rHCW 3.297, p < 0.0001 vs. nrHCW 1.385, p = 0.606) and among those HCW being employed more than 11 years (OR 2.51, p < 0.0001***). HCV prevalence was low (HCV antibodies 1.2 \% and HCV-RNA 0.3 \%). Conclusions: Chronic HBV infection is common among Tanzanian HCWs. One third of HCWs were susceptible to HBV infection, highlighting the need for vaccination. Due to high prevalence of naturally acquired immunity against HBV pre-testing might be a useful tool to identify susceptible individuals.},
  language  = {en}
}