The role of previously unmeasured organic acids in the pathogenesis of severe malaria

IntroductionSevere falciparum malaria is commonly complicated by metabolic acidosis. Together with lactic acid (LA), other previously unmeasured acids have been implicated in the pathogenesis of falciparum malaria.MethodsIn this prospective study, we characterised organic acids in adults with severe falciparum malaria in India and Bangladesh. Liquid chromatography-mass spectrometry was used to measure organic acids in plasma and urine. Patients were followed until recovery or death.ResultsPatients with severe malaria (n=138), uncomplicated malaria (n=102), sepsis (n=32) and febrile encephalopathy (n=35) were included. Strong ion gap (mean±SD) was elevated in severe malaria (8.2 mEq/L±4.5) and severe sepsis (8.6 mEq/L±7.7) compared with uncomplicated malaria (6.0 mEq/L±5.1) and encephalopathy (6.6 mEq/L±4.7). Compared with uncomplicated malaria, severe malaria was characterised by elevated plasma LA, hydroxyphenyllactic acid (HPLA), α-hydroxybutyric acid and β-hydroxybutyric acid (all P<0.05). In urine, concentrations of methylmalonic, ethylmalonic and α-ketoglutaric acids were also elevated. Multivariate logistic regression showed that plasma HPLA was a strong independent predictor of death (odds ratio [OR] 3.5, 95 % confidence interval [CI] 1.6–7.5, P=0.001), comparable to LA (OR 3.5, 95 % CI 1.5–7.8, P=0.003) (combined area under the receiver operating characteristic curve 0.81).ConclusionsNewly identified acids, in addition to LA, are elevated in patients with severe malaria and are highly predictive of fatal outcome. Further characterisation of their sources and metabolic pathways is now needed.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1023-5) contains supplementary material, which is available to authorized users.     

Identification of Host Proteins Involved in Rickettsial Invasion of Tick Cells

Tick-borne spotted fever group (SFG) Rickettsia species are obligate intracellular bacteria capable of infecting both vertebrate and invertebrate host cells, an essential process for subsequent bacterial survival in distinct hosts. The host cell signaling molecules involved in the uptake of Rickettsia into mammalian and Drosophila cells have been identified; however, invasion into tick cells is understudied. Considering the movement of SFG Rickettsia between vertebrate and invertebrate hosts, the hypothesis is that conserved mechanisms are utilized for host cell invasion. The current study employed biochemical inhibition assays to determine the tick proteins involved in Rickettsia montanensis infection of tick-derived cells from a natural host, Dermacentor variabilis. The results revealed several tick proteins important for rickettsial invasion, including actin filaments, actin-related protein 2/3 complex, phosphatidylinositol-3′-kinase, protein tyrosine kinases (PTKs), Src family PTK, focal adhesion kinase, Rho GTPase Rac1, and neural Wiskott-Aldrich syndrome protein. Delineating the molecular mechanisms of rickettsial infection is critical to a thorough understanding of rickettsial transmission in tick populations and the ecology of tick-borne rickettsial diseases.     

Anticancer effect of the extracts from Polyalthia evecta against human hepatoma cell line (HepG2)

Objective

To investigate the anticancer activity of Polyalthia evecta (P. evecta) (Pierre) Finet & Gagnep against human hepatoma cell line (HepG2).

Methods

The anticancer activity was based on (a) the cytotoxicity against human hepatoma cells (HepG2) assessed using a neutral red assay and (b) apoptosis induction determined by evaluation of nuclei morphological changes after DAPI staining. Preliminary phytochemical analysis of the crude extract was assessed by HPLC analysis.

Results

The 50% ethanol-water crude leaf extract of P. evecta (EW-L) showed greater potential anticancer activity with high cytotoxicity [IC₅₀ = (62.8 ± 7.3)µg/mL] and higher selectivity in HepG2 cells than normal Vero cells [selective index (SI) = 7.9]. The SI of EW-L was higher than the positive control, melphalan (SI = 1.6) and the apoptotic cells (46.4 ± 2.6) % induced by EW-L was higher than the melphalan (41.6 ± 2.1)% (P<0.05). The HPLC chromatogram of the EW-L revealed the presence of various kinds of polyphenolics and flavonoids in it.

Conclusions

P. evecta is a potential plant with anticancer activity. The isolation of pure compounds and determination of the bioactivity of individual compounds will be further performed.     

Homologous genetic recombination in the yellow head complex of nidoviruses infecting Penaeus monodon shrimp

Yellow head virus (YHV) is a highly virulent pathogen of Penaeus monodon shrimp. It is one of six known genotypes in the yellow head complex of nidoviruses which also includes mildly pathogenic gill-associated virus (GAV, genotype 2) and four other genotypes (genotypes 3-6) that have been detected only in healthy shrimp. In this study, comparative phylogenetic analyses conducted on replicase- (ORF1b) and glycoprotein- (ORF3) gene amplicons identified 10 putative natural recombinants amongst 28 viruses representing all six genotypes from across the Indo-Pacific region. The ∼ 4.6 kb genomic region spanning the two amplicons was sequenced for three putative recombinant viruses from Vietnam (genotype 3/5), the Philippines (genotype 5/2) and Indonesia (genotype 3/2). SimPlot analysis using these and representative parental virus sequences confirmed that each was a recombinant genotype and identified a recombination hotspot in a region just upstream of the ORF1b C-terminus. Maximum-likelihood breakpoint analysis predicted identical crossover positions in the Vietnamese and Indonesian recombinants, and a crossover position 12 nt upstream in the Philippine recombinant. Homologous genetic recombination in the same genome region was also demonstrated in recombinants generated experimentally in shrimp co-infected with YHV and GAV. The high frequency with which natural recombinants were identified indicates that genetic exchange amongst genotypes is occurring commonly in Asia and playing a significant role in expanding the genetic diversity in the yellow head complex. This is the first evidence of genetic recombination in viruses infecting crustaceans and has significant implications for the pathogenesis of infection and diagnosis of these newly emerging invertebrate pathogens.     

Estimated dietary sodium intake in Thailand: A nationwide population survey with 24‐hour urine collections

Thailand has committed to reducing population sodium intake by 30% by 2025. However, reliable nationally representative data are unavailable for monitoring progress toward the goal. We estimated dietary sodium consumption using 24‐hour urinary analyses in a nationally representative, cross‐sectional population‐based survey. We selected 2388 adults (aged ≥ 18 years) from the North, South, North‐east, Central Regions, and Bangkok, using multi‐stage cluster sampling. Mean sodium excretion was inflated by 10% to adjust for non‐urinary sources. Multivariate logistic regression was performed to assess factors associated with sodium consumption ≥ 2000 mg. Among 1599 (67%) who completed urine collection, mean age was 43 years, 53% were female, and 30% had hypertension. Mean dietary sodium intake (mg/day) was 3636 (±1722), highest in South (4108 ± 1677), and lowest in North‐east (3316 ± 1608). Higher sodium consumption was independently associated with younger age (Adjusted Odds Ratio (AOR) 2.81; 95% Confidence interval (CI): 1.53‐5.17; p = .001); higher education (AOR 1.79; 95% CI: 1.19‐2.67; p = .005), BMI ≥ 25 (AOR 1.55; 95% CI: 1.09‐2.21; p=.016), and hypertension (AOR 1.58; 95% CI: 1.02‐2.44; p = .038). Urine potassium excretion was 1221 mg/day with little variation across Regions. Estimated dietary sodium consumption in Thai adults is nearly twice as high as recommended levels. These data provide a benchmark for future monitoring.     

Synergistic anticancer effect of the extracts from Polyalthia evecta caused apoptosis in human hepatoma (HepG2) cells

Objective

To evaluate the anticancer activity of the extract fraction of Polyalthia evecta (P. evecta) (Pierre) Finet & Gagnep and the synergistic anticancer effect of the extracts from P. evecta by using the ATR/FT-IR spectroscopy.

Methods

The 50% ethanol-water crude leaf extract of P. evecta (EW-L) was prepared and was further fractionated to isolate various fractions. The anticancer activity was investigated from cytotoxicity against HepG2 using a neutral red assay and apoptosis induction by evaluation of nuclei morphological changes after DAPI staining. Synergistic anticancer effects of the extracts from P. evecta were performed using the ATR/FT-IR spectroscopy.

Results

The result showed that the EW-L showed higher cytotoxicity and apoptosis induction in HepG2 cells than its fractionated extracts. The hexane extract exhibited higher cytotoxicity and apoptosis induction than the water extracts, but less than the EW-L. The combined water and hexane extracts apparently increased cytotoxicity and apoptosis induction. The %apoptotic cells induced by the extract mixture were increased about 2-fold compared to the single hexane extract.

Conclusions

The polar extract fraction is necessary for the anticancer activity of the non-polar extract fraction. The ATR/FT-IR spectra illustrates the physical interaction among the constituents in the extract mixture and reveals the presence of polyphenolic constituents in the EW-L, which might play a role for the synergistic anticancer effect.     

Evaluation of the anticancer potential of six herbs against a hepatoma cell line

ABSTRACT: BACKGROUND: Six herbs in the Plant Genetics Conservation Project that have been used as complementary medicines were chosen on the basis of their medicinal value, namely Terminalia mucronata, Diospyros winitii, Bridelia insulana, Artabotrys harmandii, Terminallia triptera, and Croton oblongifolius. This study aims to evaluate the potential anticancer activity of 50% ethanolwater extracts of these six herbs. METHODS: Fifty percent ethanol-water crude extracts of the six herbs were prepared. The cytotoxicity of the herbal extracts relative to that of melphalan was evaluated using a hepatoma cell line (HepG2), and examined by neutral red assays and apoptosis induction by gel electrophoresis and flow cytometry after 24 h. RESULTS: A significant difference was found between the cytotoxicity of the 50% ethanol-water crude extracts and melphalan (P = 0.000). The 50% ethanol-water crude extracts of all six herbs exhibited cytotoxicity against HepG2 cells, with IC50 values ranging from 100 to 500 mug/mL. The extract of T. triptera showed the highest cytotoxicity with an IC50 of 148.7 +/- 12.3 mug/mL, while melphalan had an IC50 of 39.79 +/- 7.62 mug/mL. The 50% ethanol-water crude extracts of D. winitii and T. triptera, but not A. harmandii, produced a DNA ladder. The 50% ethanolwater crude extracts of D. winitii, T. triptera, and A. harmandii induced apoptosis detected by flow cytometry. CONCLUSION: The 50% ethanol-water crude extracts of D. winitii, T. triptera, and A. harmandii showed anticancer activity in vitro.     

Structural and antigenic analysis of the yellow head virus nucleocapsid protein p20

Yellow head virus (YHV) is an invertebrate nidovirus that is highly pathogenic for marine shrimp. Nucleotide sequence analysis indicated that the YHV ORF2 gene encodes a basic protein (pI = 9.9) of 146 amino acids with a predicted molecular weight of 16,325.5 Da. The deduced amino acid sequence indicated a predominance of basic (15.1%), acidic (9.6%) and hydrophilic polar (34.3%) residues and a high proportion proline and glycine residues (16.4%). The ORF2 gene was cloned and expressed in Escherichia coli as a M(r) = 21 kDa His(6)-protein that reacted with YHV nucleoprotein (p20) monoclonal antibody. Segments representing the four linear quadrants of the nucleoprotein were also expressed in E. coli as GST-fusion proteins. Immunoblot analysis using YHV polyclonal rabbit antiserum indicated the presence of linear epitopes in all except the V(37)-Q(74) quadrant. Immunoblot analysis of the GST-fusion proteins and C-terminally truncated segments of the nucleoprotein allowed mapping of YHV monoclonal antibodies Y19, Y20 and YII4 to linear epitopes in the acidic domain between amino acids I(116) and E(137). The full-length nucleoprotein was expressed at high level in E. coli and was easily purified in quantity from the soluble cell fraction by Ni(+)-NTA affinity chromatography.     

Efficacy and Toxicity of Idarubicin Versus High-dose Daunorubicin for Induction Chemotherapy in Adult Acute Myeloid Leukemia: A Systematic Review and Meta-analysis

Background

The 2 main formulations of anthracycline used for acute myeloid leukemia (AML) induction therapy are idarubicin (IDA) and daunorubicin.