The influence of different flow velocities on tumor cell survival in micropore filters

Earlier studies have shown a lower degree of lodgement and early survival of tumor cells in muscle than in liver after infusion via the femoral artery and portal vein, respectively. A possible explanation to this difference might be that the tumor cells are mechanically destroyed, and thus die more rapidly in muscle because they enter this capillary network at a much higher flow velocity. In the present study, the effect on early tumor cell (rat fibrosarcoma) survival of a high and a low flow velocity/deformation rate was evaluated in micropore (5 μm) filters, using isotope (Cr⁵¹) technique. These experiments were combined with scanning electron microscopic (SEM) analyses. The filter experiments showed no significant differences in the rate of cell death in the filters between tumor cells subjected to high or low deformation rates, and there were no qualitative differences in tumor cell appearance in the SEM study. It is, therefore, concluded that the difference in tumor cell lodgement and survival between muscle and liver is not primarily caused by differences in the rate of cell deformation upon entry of the organ capillary network.     

Bayesian Geostatistical Model-Based Estimates of Soil-Transmitted Helminth Infection in Nigeria,Including Annual Deworming Requirements

Background

The acceleration of the control of soil-transmitted helminth (STH) infections in Nigeria, emphasizing preventive chemotherapy, has become imperative in light of the global fight against neglected tropical diseases. Predictive risk maps are an important tool to guide and support control activities.

Methodology

STH infection prevalence data were obtained from surveys carried out in 2011 using standard protocols. Data were geo-referenced and collated in a nationwide, geographic information system database. Bayesian geostatistical models with remotely sensed environmental covariates and variable selection procedures were utilized to predict the spatial distribution of STH infections in Nigeria.

Principal Findings

We found that hookworm, Ascaris lumbricoides, and Trichuris trichiura infections are endemic in 482 (86.8%), 305 (55.0%), and 55 (9.9%) locations, respectively. Hookworm and A. lumbricoides infection co-exist in 16 states, while the three species are co-endemic in 12 states. Overall, STHs are endemic in 20 of the 36 states of Nigeria, including the Federal Capital Territory of Abuja. The observed prevalence at endemic locations ranged from 1.7% to 51.7% for hookworm, from 1.6% to 77.8% for A. lumbricoides, and from 1.0% to 25.5% for T. trichiura. Model-based predictions ranged from 0.7% to 51.0% for hookworm, from 0.1% to 82.6% for A. lumbricoides, and from 0.0% to 18.5% for T. trichiura. Our models suggest that day land surface temperature and dense vegetation are important predictors of the spatial distribution of STH infection in Nigeria. In 2011, a total of 5.7 million (13.8%) school-aged children were predicted to be infected with STHs in Nigeria. Mass treatment at the local government area level for annual or bi-annual treatment of the school-aged population in Nigeria in 2011, based on World Health Organization prevalence thresholds, were estimated at 10.2 million tablets.

Conclusions/Significance

The predictive risk maps and estimated deworming needs presented here will be helpful for escalating the control and spatial targeting of interventions against STH infections in Nigeria.     

Schistosomiasis in Cross River State, Nigeria: 1. Prevalence and intensity of infection in Adim, Akamkpa Local Government Area

Mid-stream urine was randomly collected from 248 subjects in Adim. Blood and protein concentrations were determined semi-quantitatively using Combi-7 reagent strips. The urine samples were then processed and any ova of Schistosoma haematobium present were counted per 10 ml urine. Fresh stool samples were also randomly collected, processed and examined for S. masoni and other helminthic ova. The prevalence of S. haematobium in the area was 43.5% and this was found to be age-related but not sex-related. Mean egg count was 137.2 per 10 ml urine. Intense haematuria of 250 ery/microliters and proteinuria of 500 mg/dl accompanied the high egg counts. The stool examination showed no cases of Manson's schistosomiasis but polyparasitism with other intestinal helminths was common particularly among children under 10 years old. This is the first report of urinary schistosomiasis in this area and the high prevalence rate is consistent with the rice farming occupation of the natives of the area. The sensitive nature and the case of application of the reagent strips in determining heavy infections by measuring haematuria and proteinuria is once again confirmed.     

Histological alterations by a diet containing seeds of Garcinia kola: effect on liver, kidney, and intestine in the rat

Histological examination of liver, kidney, and duodenum of rats fed a diet containing 10% (w/w) dry powdered seeds of Garcinia kola for 6 weeks revealed cellular changes that were not observed in pair-fed control animals. The main cellular changes observed in the rats fed on Garcinia kola diet included vacuolation of duodenal villous epithelial cells, numerous intracytoplasmic vacuoles in hepatocytes, and mild hydropic degeneration in cells of the renal proximal tubular epithelium. These changes are probably due to the flavonoids contained in G. kola seeds.     

Residue specific partitioning of KL4 into phospholipid bilayers

KL₄, which has demonstrated success in the treatment of respiratory distress, is a synthetic helical, amphipathic peptide mimetic of lung surfactant protein B. The unusual periodicity of charged residues within KL₄ and its relatively high hydrophobicity distinguish it from canonical amphipathic helical peptides. Here we utilized site specific spin labeling of both lipids and the peptide coupled with EPR spectroscopy to discern the effects of KL₄ on lipid dynamics, the residue specific dynamics of hydrophobic regions within KL₄, and the partitioning depths of specific KL₄ residues into the DPPC/POPG and POPC/POPG lipid bilayers under physiologically relevant conditions. KL₄ induces alterations in acyl chain dynamics in a lipid-dependent manner, with the peptide partitioning more deeply into DPPC-rich bilayers. Combined with an earlier NMR study of changes in lipid dynamics on addition of KL₄ (V.C. Antharam et al., 2009), we are able to distinguish how KL₄ affects both collective bilayer motions and intramolecular acyl chain dynamics in a lipid-dependent manner. EPR power saturation results for spin labeled lipids demonstrate that KL₄ also alters the accessibility profiles of paramagnetic colliders in a lipid-dependent manner. Measurements of dynamics and depth parameters for individual spin-labeled residues within KL₄ are consistent with a model where the peptide partitions deeply into the lipid bilayers but lies parallel to the bilayer interface in both lipid environments; the depth of partitioning is dependent on the degree of lipid acyl chain saturation within the bilayer.     

The influence of different flow velocities on tumor cell survival in micropore filters.

Earlier studies have shown a lower degree of lodgement and early survival of tumor cells in muscle than in liver after infusion via the femoral artery and portal vein, respectively. A possible explanation to this difference might be that the tumor cells are mechanically destroyed, and thus die more rapidly in muscle because they enter this capillary network at a much higher flow velocity. In the present study, the effect on early tumor cell (rat fibrosarcoma) survival of a high and a low flow velocity/deformation rate was evaluated in micropore (5 microns) filters, using isotope (Cr51) technique. These experiments were combined with scanning electron microscopic (SEM) analyses. The filter experiments showed no significant differences in the rate of cell death in the filters between tumor cells subjected to high or low deformation rates, and there were no qualitative differences in tumor cell appearance in the SEM study. It is, therefore, concluded that the difference in tumor cell lodgement and survival between muscle and liver is not primarily caused by differences in the rate of cell deformation upon entry of the organ capillary network.