Emerging zoonotic infectious diseases pose a serious threat to global health. This is especially true in relation to the great apes, whose close phylogenetic relationship with humans results in a ...high potential for microorganism exchange. In this review, we show how studies of the microorganisms of wild great apes can lead to the discovery of novel pathogens of importance for humans. We also illustrate how these primates, living in their natural habitats, can serve as sentinels for outbreaks of human disease in regions with a high likelihood of disease emergence. Greater sampling efforts and improvements in sample preservation and diagnostic capacity are rapidly improving our understanding of the diversity and distribution of microorganisms in wild great apes. Linking non-invasive diagnostic data with observational health data from great apes habituated to human presence is a promising approach for the discovery of pathogens of high relevance for humans.
In this contribution, an ultrawideband (UWB) microwave system for breast cancer detection is presented. The system is based on a novel hemispherical real-aperture antenna array, which is employed in ...a multi-static radar-based detection system. The array consists of 16 UWB aperture-coupled stacked-patch antennas located on a section of a hemisphere. The radar system is designed to be used with realistic three-dimensional (3D) breast phantoms, which have been developed, as well as with real breast cancer patients during initial clinical trials. Images are formed using two different beamforming algorithms and the performance of these algorithms is firstly compared through numerical simulation. Experimental results for the same beamforming techniques are then presented, demonstrating the successful detection of 4 and 6 mm diameter spherical tumors in the curved breast phantom.
This letter presents, for the first time, experimental work on microwave breast cancer imaging using inhomogeneous breast phantoms. A recently designed 31-antenna array is used in imaging ...experiments. The imaging system operates in the full ultrawideband frequency range, between 3 and 10 GHz. To verify imaging performance of our system, new breast phantoms with inhomogeneous interior were developed. For three different breast phantoms presented in this work, the contrast between spherical phantom tumors and surrounding materials ranges from 5:1 to 1.6:1. Our results show that the biggest challenge in radar microwave imaging is the inhomogeneity of the volume being sensed, and not the contrast itself. In addition to experimental results, we also present the new image formation algorithm, which is a modified version of the delay-and-sum (DAS) algorithm. The new algorithm makes use of a new weighting factor, the coherence factor. The new algorithm is effective in reducing clutter, providing better images. For the most demanding imaging example presented herein, the new algorithm improves the peak clutter-to-target energy ratio by 3.1 dB.
Polyomaviruses are a family of small non-enveloped DNA viruses that encode oncogenes and have been associated, to greater or lesser extent, with human disease and cancer. Currently, twelve ...polyomaviruses are known to circulate within the human population. To further examine the diversity of human polyomaviruses, we have utilized a combinatorial approach comprised of initial degenerate primer-based PCR identification and phylogenetic analysis of nonhuman primate (NHP) polyomavirus species, followed by polyomavirus-specific serological analysis of human sera. Using this approach we identified twenty novel NHP polyomaviruses: nine in great apes (six in chimpanzees, two in gorillas and one in orangutan), five in Old World monkeys and six in New World monkeys. Phylogenetic analysis indicated that only four of the nine chimpanzee polyomaviruses (six novel and three previously identified) had known close human counterparts. To determine whether the remaining chimpanzee polyomaviruses had potential human counterparts, the major viral capsid proteins (VP1) of four chimpanzee polyomaviruses were expressed in E. coli for use as antigens in enzyme-linked immunoassay (ELISA). Human serum/plasma samples from both Côte d'Ivoire and Germany showed frequent seropositivity for the four viruses. Antibody pre-adsorption-based ELISA excluded the possibility that reactivities resulted from binding to known human polyomaviruses. Together, these results support the existence of additional polyomaviruses circulating within the human population that are genetically and serologically related to existing chimpanzee polyomaviruses.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Hantaviruses are members of the Bunyaviridae family carried by small mammals and causing human hemorrhagic fevers worldwide. In Western Africa, where a variety of hemorrhagic fever viruses occurs, ...indigenous hantaviruses have been molecularly found in animal reservoirs such as rodents, shrews, and bats since 2006. To investigate the human contact to hantaviruses carried by these hosts and to assess the public health relevance of hantaviruses for humans living in the tropical rainforest regions of Western and Central Africa, we performed a cross-sectional seroprevalence study in the region of Taï National Park in Côte d'Ivoire and the Bandundu region near the Salonga National Park in the Democratic Republic (DR) of Congo. Serum samples were initially screened with enzyme-linked immunosorbent assays using nucleoproteins of several hantaviruses as diagnostic antigens. Positive results were confirmed by Western blotting and immunofluorescence testing. Seroprevalence rates of 3.9% (27/687) and 2.4% (7/295), respectively, were found in the investigated regions in Côte d'Ivoire and the DR Congo. In Côte d'Ivoire, this value was significantly higher than the seroprevalence rates previously reported from the neighboring country Guinea as well as from South Africa. Our study indicates an exposure of humans to hantaviruses in West and Central African tropical rainforest areas. In order to pinpoint the possible existence and frequency of clinical disease caused by hantaviruses in this region of the world, systematic investigations of patients with fever and renal or respiratory symptoms are required.
This paper presents an improved antenna array for radar-based breast cancer imaging. The improvement was achieved by increasing the number of antennas in the array to 31 elements, as well as by ...improving the antenna design itself. Using an experimental setup, with homogeneous curved breast phantoms, we have demonstrated substantial imaging improvement with the new antenna array. The new system is also able to detect 7 mm-diameter tumor phantoms in any location within the breast, even as close as 4 mm from the skin layer. Additionally, we have shown good imaging results in low-contrast scenarios, where the dielectric contrast between tumor and normal tissue was reduced to 2:1. Presented results clearly demonstrate the large impact of antenna's characteristics on imaging performance.
The significance of glucocorticoid pulsatility Lightman, Stafford L.; Wiles, Crispin C.; Atkinson, Helen C. ...
European journal of pharmacology,
04/2008, Letnik:
583, Številka:
2
Journal Article
Recenzirano
Glucocorticoids are secreted in discrete pulses resulting in an ultradian rhythm in all species that have been studied. In the rat there is an approximately hourly rhythm of corticosterone secretion, ...which appears to be regulated by alternating activation and inhibition of the HPA axis. At the level of signal transduction, the response to these pulses of corticosterone is determined by its dynamic interaction with the two transcription factors — the glucocorticoid and mineralocorticoid receptors. While the mineralocorticoid receptor remains activated throughout the ultradian cycle, the glucocorticoid receptor shows a phasic response to each individual pulse of corticosterone. This phasic response is regulated by an intranuclear proteasome-dependent rapid downregulation of the activated glucocorticoid receptor.
The severe Ebola virus disease epidemic occurring in West Africa stems from a single zoonotic transmission event to a 2‐year‐old boy in Meliandou, Guinea. We investigated the zoonotic origins of the ...epidemic using wildlife surveys, interviews, and molecular analyses of bat and environmental samples. We found no evidence for a concurrent outbreak in larger wildlife. Exposure to fruit bats is common in the region, but the index case may have been infected by playing in a hollow tree housing a colony of insectivorous free‐tailed bats (Mops condylurus). Bats in this family have previously been discussed as potential sources for Ebola virus outbreaks, and experimental data have shown that this species can survive experimental infection. These analyses expand the range of possible Ebola virus sources to include insectivorous bats and reiterate the importance of broader sampling efforts for understanding Ebola virus ecology.
Synopsis
The severe Ebola virus disease epidemic occurring in West Africa likely stems from a single zoonotic transmission event involving a 2‐year‐old boy in Meliandou, Guinea, who might have been infected by hunting or playing with insectivorous free‐tailed bats living in a nearby hollow tree.
Monitoring data show that larger wildlife did not experience a recent decline and is therefore unlikely to have served as the source for the Ebola virus disease epidemic in West Africa.
Fruit bat hunting and butchering are common activities in southern Guinea, therefore facilitating direct human contact.
Children are also exposed to insectivorous bats through hunting in and around villages.
No large colony of fruit bats exists in or nearby the index village (Meliandou).
The 2‐year‐old index case may have been infected by playing in a hollow tree housing a colony of insectivorous free‐tailed bats (Mops condylurus).
The severe Ebola virus disease epidemic occurring in West Africa likely stems from a single zoonotic transmission event involving a 2‐year‐old boy in Meliandou, Guinea, who might have been infected by hunting or playing with insectivorous free‐tailed bats living in a nearby hollow tree.
Few lethal pathogens in wild‐living primates have been described, and little is known about infectious diseases of the reproductive tract and their possible impact on health and reproduction. This ...report describes the pathology and isolation of an alpha‐toxin producing strain of Clostridium septicum in a case of necrotizing endometritis in a wild sooty mangabey found dead in a tropical rainforest of West Africa.
Zoonotic transmission events play a major role in the emergence of novel diseases. While such events are virtually impossible to predict, wildlife screening for potential emerging pathogens can be a ...first step. Driven by recent disease epidemics like severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and Ebola, bats have gained special interest as reservoirs of emerging viruses.
As part of a bigger study investigating pathogens in African bats we screened animals for the presence of known and unknown viruses.
We isolated and characterised a novel reovirus from blood of free-tailed bats (Chaereophon aloysiisabaudiae) captured in 2006 in Côte d'Ivoire. The virus showed closest relationship with two human pathogenic viruses, Colorado tick fever virus and Eyach virus, and was able to infect various human cell lines in vitro.
The study shows the presence of a coltivirus-related virus in bats from Sub-Sahara Africa. Serological studies could help to assess its impact on humans or wildlife health.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
