Mouse lymphoma thymidine kinase gene mutation assay: meeting of the International Workshop on Genotoxicity Testing, San Francisco, 2005, recommendations for 24-h treatment

The Mouse Lymphoma Assay (MLA) Workgroup of the International Workshop on Genotoxicity Testing (IWGT), comprised of experts from Japan, Europe and the United States, met on September 9, 2005, in San Francisco, CA, USA. This meeting of the MLA Workgroup was devoted to reaching a consensus on issues involved with 24-h treatment. Recommendations were made concerning the acceptable values for the negative/solvent control (mutant frequency, cloning efficiency and suspension growth) and the criteria to define an acceptable positive control response. Consensus was also reached concerning the use of the global evaluation factor (GEF) and appropriate statistical trend analysis to define positive and negative responses for the 24-h treatment. The Workgroup agreed to continue their support of the International Committee on Harmonization (ICH) recommendation that the MLA assay should include a 24-h treatment (without S-9) in those situations where the short treatment (3-4 h) gives negative results.     

Extradural spinal meningioma as a source of plasmacytoid cells. A case report

BACKGROUND: Meningiomas, tumors that often affect middle-aged and elderly people, occasionally arise in the spine, typically at the thoracic level. The cytologic findings in meningiomas include whorls and syncytial clusters of bland-looking cells with scattered, psammomatous calcifications and intranudclear cytoplasmic inclusions. However, in many cases, not all these findings are seen, and in rare cases, unusual cytomorphologic features are observed. CASE: A case of spinal meningioma was located in the extradural compartment and composed predominantly of singly scattered cells with a plasmacytoid appearance, demonstrated on fine needle aspiration biopsy smear preparations. The cell block showed more typical features of meningioma, and the diagnosis was supported by the results of immunohistochemical staining. CONCLUSION: The diagnosis of spinal meningioma is readily made by employing magnetic resonance imaging. The diagnosis can be difficult to confirm pathologically when atypical histologic findings are present, as in this case, with prominent plasmacytoid features. Sections from the cell block and immunohistochemical stains as well as clinical and radiologic findings were extremely helpful in arriving at the final diagnosis.     

Characterization and Detection of Endolysin Gene from Three Acinetobacter baumannii Bacteriophages Isolated from Sewage Water

Acinetobacter baumannii is an opportunistic pathogen that exists in hospital environments. The emergence of multidrug resistant A. baumannii (MDRAB) has been reported worldwide. It is necessary to find a novel and effective treatment for MDRAB infection. In this study, three bacteriophages, designated as ØABP-01, ØABP-02 and ØABP-04 were selected for analysis. Transmission electron microscopy showed that bacteriophage ØABP-01 belonged to the Podoviridae family and bacteriophage ØABP-02 and ØABP-04 are classified into the family Myoviridae. ØABP-01 had the widest host range. ØABP-01, ØABP-02 and ØABP-04 exhibited a latent period of 15, 20 and 20 min. The burst sizes of the three bacteriophages were 110, 120 and 150 PFU/cell. DNA restriction analysis using EcoRI, HindIII, PstI, SphI, BamHI and SmaI showed different DNA fragment patterns between the three bacteriophages. ØABP-01 and ØABP-04 was positive for the endolysin gene as determined by PCR. In conclusion, bacteriophage ØABP-01 showed broad host-specificity, good lytic activity and a short latency period, making it an appropriate candidate for studying the control and diagnosis associated with MDRAB infections.     

Influence of cGMP on Feeding Potential of Predatory Coccinellid,Cryptolaemus montrouzieri Mulsant and Isolation of Partial foraging Gene

The cyclic guanomonophosphate (cGMP) dependent protein kinase (PKG) plays an important role in the food related behaviours of several insect species. Here we report the influence of cGMP dependent PKG on prey consumption of adult predatory coccinellid, Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae). The oral cGMP treatment (which increases PKG activity) enhanced the feeding potential of C. montrouzieri. The good foragers responded more positively to the cGMP treatment compared to the poor foragers. The cGMP levels estimated through ELISA were significantly (P?<?0.001) high in the digestive tissues of unfed as well as cGMP treated C. montrouzieri compared to normal fed beetles. This finding suggests that cGMP is involved in the higher feeding rates of C. montrouzieri and the partial foraging gene (~455 bp) which encodes the cGMP dependent PKG was isolated from genomic DNA of C. montrouzieri using gene specific primers.     

Clinical and Epidemiological Features of Typhoid Fever in Pemba,Zanzibar: Assessment of the Performance of the WHO Case Definitions

Background

The gold standard for diagnosis of typhoid fever is blood culture (BC). Because blood culture is often not available in impoverished settings it would be helpful to have alternative diagnostic approaches. We therefore investigated the usefulness of clinical signs, WHO case definition and Widal test for the diagnosis of typhoid fever.

Methodology/Principal Findings

Participants with a body temperature ≥37.5°C or a history of fever were enrolled over 17 to 22 months in three hospitals on Pemba Island, Tanzania. Clinical signs and symptoms of participants upon presentation as well as blood and serum for BC and Widal testing were collected. Clinical signs and symptoms of typhoid fever cases were compared to other cases of invasive bacterial diseases and BC negative participants. The relationship of typhoid fever cases with rainfall, temperature, and religious festivals was explored. The performance of the WHO case definitions for suspected and probable typhoid fever and a local cut off titre for the Widal test was assessed. 79 of 2209 participants had invasive bacterial disease. 46 isolates were identified as typhoid fever. Apart from a longer duration of fever prior to admission clinical signs and symptoms were not significantly different among patients with typhoid fever than from other febrile patients. We did not detect any significant seasonal patterns nor correlation with rainfall or festivals. The sensitivity and specificity of the WHO case definition for suspected and probable typhoid fever were 82.6% and 41.3% and 36.3 and 99.7% respectively. Sensitivity and specificity of the Widal test was 47.8% and 99.4 both forfor O-agglutinin and H- agglutinin at a cut-off titre of 1∶80.

Conclusions/Significance

Typhoid fever prevalence rates on Pemba are high and its clinical signs and symptoms are non-specific. The sensitivity of the Widal test is low and the WHO case definition performed better than the Widal test.     

Carbon Accumulation Patterns During Post-Fire Succession in Cajander Larch (Larix cajanderi) Forests of Siberia

Increased fire activity within boreal forests could affect global terrestrial carbon (C) stocks by decreasing stand age or altering tree recruitment, leading to patterns of forest regrowth that differ from those of pre-fire stands. To improve our understanding of post-fire C accumulation patterns within boreal forests, we evaluated above- and belowground C pools within 17 Cajander larch (Larix cajanderi) stands of northeastern Siberia that varied in both years since fire and stand density. Early-successional stands (<20-year old) exhibited low larch recruitment, and consequently, low density, aboveground larch biomass, and aboveground net primary productivity (ANPP_tree). Mid-successional stands (21- to 70-year old) were even-aged with considerable variability in stand density. High-density mid-successional stands had 21 times faster rates of ANPP_tree than low-density stands (252 vs. 12?g?C?m^?2?y^?1) and 26 times more C in aboveground larch biomass (2,186 vs. 85?g?C?m^?2). Density had little effect on total soil C pools. During late-succession (>70-year old), aboveground larch biomass, ANPP_tree, and soil organic layer C pools increased with stand age. These stands were low density and multi-aged, containing both mature trees and new recruits. The rapid accumulation of aboveground larch biomass in high-density, mid-successional stands allowed them to obtain C stocks similar to those in much older low-density stands (~8,000?g?C?m^?2). If fire frequency increases without altering stand density, landscape-level C storage could decline, but if larch density also increases, large aboveground C pools within high-density stands could compensate for a shorter successional cycle.     

Dynamics in the size structure of Skeletonema costatum (Greville) Cleve under conditions of reduced photosynthetically available radiation in a dredged tropical estuary

This study investigates the size-fractionated productivity and chlorophyll a concentrations in Ponggol estuary, a heavily dredged, light-limited and eutrophic tropical estuary located on the northeastern coast of Singapore. A 90% reduction in the photosynthetically available radiation (PAR) was seen in the subsurface waters of the dredged stations, when compared to an average reduction of about 75% in the subsurface waters of the un-dredged station. High phytoplankton production rates and chlorophyll a concentrations were recorded in the surface waters, with a significant reduction in the subsurface waters, especially at the two dredged stations. Out of the four size-classes of phytoplankton (0.2-2 μm, 2-20 μm, 20-200 μm and >200 μm) investigated, the relative dominance of the smaller size class of 2-20 μm over the 20-200 μm size class shifted depending on the availability of PAR. The size class 2-20 μm was observed to contribute up to 60 and 57% of the total production, respectively, in the surface waters of the un-dredged and dredged stations of the estuary. A relatively major contribution of 49% came from the cells of the small size-fraction of 2-20 μm in the subsurface waters of the un-dredged station. On the contrary, cells of the 20-200 μm size-class contributed up to 58% in the subsurface waters of the dredged station. Microscopic examination of the phytoplankton cells sampled showed morphological differences in the cells of the phytoplankton species Skeletonema costatum with some cells being distinctly larger in size than others. The larger cells were predominant in the dredged subsurface waters. In situ mesocosms with treatments exposed to high light irradiation registered a significant contribution by the smaller size-class of 2-20 μm, in contrast to the larger 20-200 μm dominating in the two treatments subjected to low light conditions. Based on the observations in this study and a review of the literature, it is hypothesized that the cells of S. costatum may actually be of two genetically different strains, whose relative dominance in the environment may be controlled by the quantum of available light. Thus, this shift in the relative dominance of one size fraction over the other is a response to altered PAR levels as the result of dredging.     

The MHC class II-associated invariant chain interacts with the neonatal Fc gamma receptor and modulates its trafficking to endosomal/lysosomal compartments

The neonatal Fc receptor for IgG (FcRn) transfers maternal IgG to the offspring and protects IgG from degradation. The FcRn resides in an acidic intracellular compartment, allowing it to bind IgG. In this study, we found the association of FcRn and invariant chain (Ii). The interaction was initiated within the endoplasmic reticulum by Ii binding to either the FcRn H chain alone or FcRn H chain-beta(2)-microglobulin complex and appeared to be maintained throughout the endocytic pathway. The CLIP in Ii was not required for FcRn-Ii association. The interaction was also detected in IFN-gamma-treated THP-1, epithelial and endothelial cells, and immature mouse DCs. A truncated FcRn without the cytoplasmic tail was unable to traffic to early endosomes; however, its location in early endosomes was restored by Ii expression. FcRn was also detected in the late endosome/lysosome only in the presence of Ii or on exposure to IFN-gamma. In immature human or mouse DCs, FcRn was barely detected in the late endosome/lysosome in the absence of Ii. Furthermore, the cytoplasmic tail of Ii conferred tailless FcRn to route to both the early endosome and late endosome/lysosome in a hybrid molecule. Because the FcRn is expressed in macrophages and DCs or epithelial and endothelial cells where Ii is induced under inflammation and infection, these results reveal the complexity of FcRn trafficking in which Ii is capable of expanding the boundary of FcRn trafficking. Taken together, the intracellular trafficking of FcRn is regulated by its intrinsic sorting information and/or an interaction with Ii chain.