234 research outputs found
The search for stem cells of the epithelium in pulmonary alveoli
In recent years significant progress has been witnessed in the identification of
stem cells, which have now also been identified in the lungs. The aim of this was
to induce post-pneumonia alveolar regeneration to facilitate the identification
of stem cells. The studies were performed on Buffalo strain rats. Pneumonia was
induced in the animals by a sub-pleural injection of carragenin. On days 4, 5 and
10 of the experiment both the control and experimental animals received intraperitoneal
injections of bromodeoxyuridine (BrdU). Twenty-four hours after the
last BrdU injection the rats were sacrificed and samples of the lungs were taken
for examination. In order to detect proliferating cells in the paraffin sections,
BrdU incorporation was detected with monoclonal antibodies. In pilot experiments
BrdU incorporation was demonstrated in individual alveolar cells of variable
distribution and of variable intensity in the colour reaction. The results have
confirmed the existence of stem cells in pulmonary alveoli but their closer characterisation
requires further studies with other techniques to detect pulmonary
stem cells
Technological Support for a Learning Oriented Knowledge Management System
Knowledge management is quickly becoming a requirement for today’s complex organizations. Creating and managing existing knowledge has been linked to successful innovation and to sustainable competitive advantage. However, systems specifically designed to manage knowledge, support knowledge creation, and verify existing knowledge are in their infancy. This article follows the framework for a Learning-Oriented Knowledge Management System, and shows how such a complex system can be supported by an equally complex technology – that is, a multi-agent system. We define single agents and multi-agent systems and subsystems in the context of knowledge management systems in general, and the Learning-Oriented Knowledge Management System (LOKMS) specifically. We show how a multi-agent system can be conceived to fully support the LOKMS, describe some necessary agents and agent subsystems, and demonstrate prototypically a multi-agent system designed and built to support the integrity-checking component of the LOKMS. This system begins the process of LOKMS design and development
Apoptotic changes in the myocardium in the course of experimentally-induced pleurisy
The secreted proinflammatory interleukins IL-1, IL-6 and TNF in the course of
experimentally-induced pleurisy can be the cause of pathological changes in the
ultrastructure of cardiac muscle and of apoptosis. The pleurisy was induced in rats
by means of carrageenin. The scraps of cardiac muscle obtained during the inflammatory
reaction in the pleura were analysed by means of an electron microscope.
The scraps were also stained with the TUNEL method in order to find the
apoptotic foci. It was proved by the experiment that the inflammatory process
affected mitochondria in the cardiomyocytes, enhanced collagen fibre synthesis
and contributed to the formation of apoptotic foci in the cardiac muscle
New challenges in studying nutrition-disease interactions in the developing world.
Latest estimates indicate that nutritional deficiencies account for 3 million child deaths each year in less-developed countries. Targeted nutritional interventions could therefore save millions of lives. However, such interventions require careful optimization to maximize benefit and avoid harm. Progress toward designing effective life-saving interventions is currently hampered by some serious gaps in our understanding of nutrient metabolism in humans. In this Personal Perspective, we highlight some of these gaps and make some proposals as to how improved research methods and technologies can be brought to bear on the problems of undernourished children in the developing world
Challenges of tuberculosis management in high and low prevalence countries in a mobile world
This article is made available via the PMC Open Access Subset for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.In this issue of the PCRJ, Bishara et al.
1 present a case report about
the treatment of a pregnant woman with tuberculosis (TB). She had
emigrated from a country with a high prevalence of TB to one with
a lower prevalence. This presented a challenge to her physicians who
were faced with identifying and treating close contacts who were
also infected. This Perspective article explores in more depth some of
the questions raised by this case report. It discusses the role of
primary care physicians in low prevalence countries who can
implement evidence-based screening programmes, it discusses
effective strategies for the diagnosis and treatment of TB in countries
with high TB prevalence, and it presents insights from medical
anthropology that can help practitioners overcome the barriers to TB
diagnosis, treatment and screening described in the case report
QuantiFERON®-TB gold in-tube performance for diagnosing active tuberculosis in children and adults in a high burden setting.
To determine whether QuantiFERON®-TB Gold In-Tube (QFT) can contribute to the diagnosis of active tuberculosis (TB) in children in a high-burden setting and to assess the performance of QFT and tuberculin skin test (TST) in a prospective cohort of TB suspect children compared to adults with confirmed TB in Tanzania. Sensitivity and specificity of QFT and TST for diagnosing active TB as well as indeterminate QFT rates and IFN-γ levels were assessed in 211 TB suspect children in a Tanzanian district hospital and contrasted in 90 adults with confirmed pulmonary TB. Sensitivity of QFT and TST in children with confirmed TB was 19% (5/27) and 6% (2/31) respectively. In adults sensitivity of QFT and TST was 84% (73/87) and 85% (63/74). The QFT indeterminate rate in children and adults was 27% and 3%. Median levels of IFN-γ were lower in children than adults, particularly children <2 years and HIV infected. An indeterminate result was associated with age <2 years but not malnutrition or HIV status. Overall childhood mortality was 19% and associated with an indeterminate QFT result at baseline. QFT and TST showed poor performance and a surprisingly low sensitivity in children. In contrast the performance in Tanzanian adults was good and comparable to performance in high-income countries. Indeterminate results in children were associated with young age and increased mortality. Neither test can be recommended for diagnosing active TB in children with immature or impaired immunity in a high-burden setting
Capillary Assembly of Anisotropic Particles at Cylindrical Fluid-Fluid Interfaces
The unique behavior of colloids at liquid interfaces provides exciting opportunities for engineering the assembly of colloidal particles into functional materials. The deformable nature of fluid-fluid interfaces means that we can use the interfacial curvature, in addition to particle properties, to direct self-assembly. To this end, we use a finite element method (Surface Evolver) to study the self-assembly of rod-shaped particles adsorbed at a simple curved fluid-fluid interface formed by a sessile liquid drop with cylindrical geometry. Specifically, we study the self-assembly of single and multiple rods as a function of drop curvature and particle properties such as shape (ellipsoid, cylinder, and spherocylinder), contact angle, aspect ratio, and chemical heterogeneity (homogeneous and triblock patchy). We find that the curved interface allows us to effectively control the orientation of the rods, allowing us to achieve parallel, perpendicular, or novel obliquely orientations with respect to the cylindrical drop. In addition, by tuning particle properties to achieve parallel alignment of the rods, we show that the cylindrical drop geometry favors tip-to-tip assembly of the rods, not just for cylinders, but also for ellipsoids and triblock patchy rods. Finally, for triblock patchy rods with larger contact line undulations, we can achieve strong spatial confinement of the rods transverse to the cylindrical drop due to the capillary repulsion between the contact line undulations of the particle and the pinned contact lines of the sessile drop. Our capillary assembly method allows us to manipulate the configuration of single and multiple rod-like particles and therefore offers a facile strategy for organizing such particles into useful functional materials
Effect of Different Factors on Proliferation of Antler Cells, Cultured In Vitro
Antlers as a potential model for bone growth and development have become an object of rising interest. To elucidate processes explaining how antler growth is regulated, in vitro cultures have been established. However, until now, there has been no standard method to cultivate antler cells and in vitro results are often opposite to those reported in vivo. In addition, many factors which are often not taken into account under in vitro conditions may play an important role in the development of antler cells. In this study we investigated the effects of the antler growth stage, the male individuality, passaged versus primary cultures and the effect of foetal calf serum concentrations on proliferative potential of mixed antler cell cultures in vitro, derived from regenerating antlers of red deer males (Cervus elaphus). The proliferation potential of antler cells was measured by incorporation of 3H thymidine. Our results demonstrate that there is no significant effect of the antler growth stage, whereas male individuality and all other examined factors significantly affected antler cell proliferation. Furthermore, our results suggest that primary cultures may better represent in vivo conditions and processes occurring in regenerating antlers. In conclusion, before all main factors affecting antler cell proliferation in vitro will be satisfactorily investigated, results of in vitro studies focused on hormonal regulation of antler growth should be taken with extreme caution
- …