Detection of malaria parasites by nested PCR in south-eastern, Iran: Evidence of highly mixed infections in Chahbahar district

Background

Rapid diagnosis and correct treatment of cases are the main objectives of control programs in malaria-endemic areas.

Methods and results

To evaluate these criteria and in a comparative study, blood specimens were collected from 120 volunteers seeking care at the Malaria Health Center in Chahbahar district. One hundred and seven out of 120 Giemsa-stained slides were positive for malaria parasites by microscopy. Eighty-four (70%) and 20 (16.7%) were identified as having only Plasmodium vivax and Plasmodium falciparum infections, respectively, while only 3 (2.5%) were interpreted as having mixed P. vivax-P. falciparum infections. The target DNA sequence of the 18S small sub-unit ribosomal RNA (ssrRNA) gene was amplified by Polymerase Chain Reaction (PCR) and used for the diagnosis of malaria in south-eastern Iran. One hundred twenty blood samples were submitted and the results were compared to those of routine microscopy. The sensitivity of PCR for detection of P. vivax and P. falciparum malaria was higher than that of microscopy: nested PCR detected 31 more mixed infections than microscopy and parasite positive reactions in 9 out of the 13 microscopically negative samples. The results also confirmed the presence of P. vivax and P. falciparum.

Conclusions

These results suggest that, in places where transmission of both P. vivax and P. falciparum occurs, nested PCR detection of malaria parasites can be a very useful complement to microscopical diagnosis.     

Iranian Breast Cancer Bio-Bank: the activity and challenging issues

The information gained from the Human Genome Project has facilitated molecular as well as cellular studies not only to find the origins of Breast Cancer (BC), but also to create novel, and effective treatments. In order to provide an infrastructure for local and international research in this area, Iranian Center for Breast Cancer (ICBC) has established a Bio-Bank (BB) for BC. This article describes the aim, structure, and activities in general, and the challenging issues confronting the bank as a model for the establishment of Bio-Banks in developing countries in particular. The methods employed by the Bank could be explained in the following categories:

• Blood and Tissue sampling,
• Preparation and Banking of collected Samples,
• Clinical and Histopathology data collection,
• Collaboration Protocol,
• Challenging issues, and the programs to confront the problems.

During the five-year activity of the bank, 110 families were enrolled for genetic counseling, from whom 600 biologic samples were obtained, including 387 blood samples and 213 tissue samples. Of 387 blood samples, 317 (82%) were found to belong to the BC patients and the remaining 70 (18%) belonged to their available relatives. The number of samples increased over the study period partly as a result of the programs designed to confront the problems. During the study period, there were some finished research studies using the samples of BB, and many other studies which are still ongoing. ICBC-BB is a model of biologic sample banking which provides a significant number of biological samples for local and international collaborative research projects regarding molecular and cellular aspects of BC. In establishing the ICBC-BB we have experienced problems and challenges, some general and some local. Some were expected and others not, but we have identified solutions.     

A benchmark dataset for canopy crown detection and delineation in co-registered airborne RGB,LiDAR and hyperspectral imagery from the National Ecological Observation Network

Broad scale remote sensing promises to build forest inventories at unprecedented scales. A crucial step in this process is to associate sensor data into individual crowns. While dozens of crown detection algorithms have been proposed, their performance is typically not compared based on standard data or evaluation metrics. There is a need for a benchmark dataset to minimize differences in reported results as well as support evaluation of algorithms across a broad range of forest types. Combining RGB, LiDAR and hyperspectral sensor data from the USA National Ecological Observatory Network’s Airborne Observation Platform with multiple types of evaluation data, we created a benchmark dataset to assess crown detection and delineation methods for canopy trees covering dominant forest types in the United States. This benchmark dataset includes an R package to standardize evaluation metrics and simplify comparisons between methods. The benchmark dataset contains over 6,000 image-annotated crowns, 400 field-annotated crowns, and 3,000 canopy stem points from a wide range of forest types. In addition, we include over 10,000 training crowns for optional use. We discuss the different evaluation data sources and assess the accuracy of the image-annotated crowns by comparing annotations among multiple annotators as well as overlapping field-annotated crowns. We provide an example submission and score for an open-source algorithm that can serve as a baseline for future methods.     

Binding of Extracellular Matrix Proteins by Enterococci

Forty-four enterococcal strains isolated from human clinical specimens were investigated for binding of ¹²⁵I-labeled fibronectin, vitronectin, thrombospondin, lactoferrin, and collagen type I and IV, and for cell surface hydrophobicity. Most strains expressed low binding of iodine-labeled human fibronectin, collagen I and IV, and higher binding of human vitronectin, human lactoferrin, and human thrombospondin. Bacteria grown in Todd-Hewitt broth exhibited increased binding to vitronectin and thrombospondin. In particle agglutination assays (PAA), Enterococcus faecalis strains reacted strongly with coated latex beads in contrast to E. faecium strains, which generally did not react. The ability of enterococci to bind ECM proteins was affected by heating and proteolytic digestion, suggesting that some protein-binding components become surface exposed after treatment with proteases. The binding of ¹²⁵I-labeled proteins to E. faecalis strain E70 was inhibited when cells were preincubated with unlabeled proteins. Preincubating cells with sulfated polymers such as dextran sulfate (M _r 5000 and 8000), pentosan sulfate and heparin decreased binding of vitronectin, lactoferrin, and thrombospondin. The binding of lactoferrin and thrombospondin was also decreased when bacteria were preincubated with galactose, fucose, and mannosamine, but not with mannose. All of 30 E. faecalis strains expressed pronounced surface hydrophobicity, but 10 of 14 E. faecium strains showed hydrophilic cell surface. Received: 22 April 1996 / Accepted: 29 June 1996     

Investigation of synergistic action between coronatine and nitric oxide in alleviating arsenic-induced toxicity in sweet basil seedlings

The phytotoxin coronatine (COR) is a jasmonic acid mimic produced by several pathovars of plant pathogen. In this study, we evaluated the protective effect of COR and nitric oxide (NO) against the toxicity of sodium arsenate in sweet basil (Ocimum basilicum L.). According to the statistical analysis, arsenic had a significant adverse effect on length and biomass of plants. Seedlings that pretreated with COR and sodium nitroprusside (SNP), significantly reversed fresh and dry lose and relative water content decay induced by the metalloid. The protective effects of COR and SNP were indicated by extent of lipid peroxidation, increase glutathione (GSH), ascorbate and thiol (–SH) content, promote antioxidant enzymes and reduce H₂O₂ content in basil seedlings. The present observation suggested that reduction of excess arsenic As-induced toxicity in O. basilicum by COR and NO is through the activation of enzymes involved in ROS detoxification (CAT, SOD, POD, APX, GR) and maintenance contents of molecular antioxidant (GSH, ascorbate, non-protein thiol and protein-thiol). Moreover, the results revealed a mutually amplifying reaction between COR and NO in reducing As-induced damages.     

Nickel-induced substrate inhibition of bovine liver glutamate dehydrogenase

The effects of nickel ions on reductive amination and oxidative deamination activities of bovine liver glutamate dehydrogenase (GDH) were examined kinetically by UV spectroscopy, at 27 degrees C, using 50 mM Tris, pH 7.8, containing 0.1 M NaCl. Kinetic analysis of the data obtained by varying NADH concentration indicated strong inhibition, presumably due to binding of the coenzyme to the regulatory site. In contrast, almost no inhibition was observed in the forward reaction. The fact that nickel ions have the capacity to enhance binding of NADH to the enzyme was confirmed by an electrochemical method using a modified glassy carbon electrode. Use of NADPH instead of NADH showed only a weak substrate inhibition, presumably related to lower affinity of NADPH for binding to the regulatory site. Lineweaver-Burk plots with respect to alpha-ketoglutarate and ammonium ions indicated substrate and competitive inhibition patterns in the presence of nickel ions, respectively. ADP at 0.2 mM concentration protected inhibition caused by nickel. These observations are explained in terms of formation of a nickel-NADH complex with a higher affinity for binding to the regulatory site in GDH, as compared with the situation where nickel is not present. Such effects may be important for regulation of GDH and other NADH-utilizing enzymes.     

A parametric method for cumulative incidence modeling with a new four-parameter log-logistic distribution

Background

The invasion of a new species into an established ecosystem can be directly compared to the steps involved in cancer metastasis. Cancer must grow in a primary site, extravasate and survive in the circulation to then intravasate into target organ (invasive species survival in transport). Cancer cells often lay dormant at their metastatic site for a long period of time (lag period for invasive species) before proliferating (invasive spread). Proliferation in the new site has an impact on the target organ microenvironment (ecological impact) and eventually the human host (biosphere impact).

Results

Tilman has described mathematical equations for the competition between invasive species in a structured habitat. These equations were adapted to study the invasion of cancer cells into the bone marrow microenvironment as a structured habitat. A large proportion of solid tumor metastases are bone metastases, known to usurp hematopoietic stem cells (HSC) homing pathways to establish footholds in the bone marrow. This required accounting for the fact that this is the natural home of hematopoietic stem cells and that they already occupy this structured space. The adapted Tilman model of invasion dynamics is especially valuable for modeling the lag period or dormancy of cancer cells.

Conclusions

The Tilman equations for modeling the invasion of two species into a defined space have been modified to study the invasion of cancer cells into the bone marrow microenvironment. These modified equations allow a more flexible way to model the space competition between the two cell species. The ability to model initial density, metastatic seeding into the bone marrow and growth once the cells are present, and movement of cells out of the bone marrow niche and apoptosis of cells are all aspects of the adapted equations. These equations are currently being applied to clinical data sets for verification and further refinement of the models.