Gap junctional intercellular communication in cells isolated from urethane-induced tumors in A/J mice

Studies using normal or neoplastically transformed established mouse lung epithelial cell lines revealed a reduction in gap junctional, intercellular communication (GJIC) with transformation. To determine the stage in tumor development at which GJIC is interrupted, we used the well-established model of lung tumors induced in strain A/J mice by urethane. In this system, tumor development follows a well-characterized pattern; hyperplasias, adenomas, and carcinomas are manifested at approximately 8, 16, and 40 weeks after urethane treatment, respectively. GJIC levels were examined using a novel technique where cells are grown on a glass slide, half of which is coated with electrically conductive, optically transparent, indium-tin oxide. An electric pulse that opens transient pores on the plasma membrane is applied in the presence of the fluorescent dye, Lucifer yellow, causing dye penetration into cells growing on the conductive part of the slide. Migration of the dye through gap junctions to nonelectroporated cells growing on the nonconductive area is then microscopically observed under fluorescence illumination. Unexpectedly, primary cells cultured from urethane-induced tumors, even late stage carcinomas, possessed extensive GJIC immediately upon isolation. Upon passage for several months however, these cells lost GJIC. These results suggest that the molecular changes that lead to the formation of the tumor in vivo are not sufficient to interrupt gap junctions. Propagation of tumor cells in culture induces additional alterations that can lead to gap junction closure.     

Fibrous carrot root responses to irrigation and compaction of sandy and organic soils

Field experiments were performed in Southern Finland on fine sand and organic soil in 1990 and 1991 to study carrot roots. Fall ploughed land was loosened by rotary harrowing to a depth of 20 cm or compacted under moist conditions to a depth of 25–30 cm by three passes of adjacent wheel tracks with a tractor weighing 3 Mg, in April were contiguously applied across the plot before seed bed preparation. Sprinkler irrigation (30 mm) was applied to fine sand when moisture in the 0–15 cm range of soil depth was 50% of plant-available water capacity. For root sampling, polyvinyl chloride (PVC) cylinders (30 × 60 cm) were installed in the rows of experimental plots after sowing, and removed at harvest. Six carrot plants were grown in each of in these soil colums in situ in the field.Fine root length and width were quantified by image analysis. Root length density (RLD) per plant was 0.2–1.0 cm cm^-3 in the 0–30 cm range. The fibrous root system of one carrot had total root lengths of 130–150 m in loose fine sand and 180–200 m in compacted fine sand. More roots were observed in irrigated than non-irrigated soils. In the 0–50 cm range of organic soil, 230–250 m of root length were removed from loosened organic soils and 240–300 m from compacted soils. Specific root surface area (surface area divided by dry root weight) of a carrot fibrous root system averaged 1500–2000 cm² g^-1. Root length to weight ratios of 250–350 m g^-1 effectively compare with the ratios of other species.Fibrous root growth was stimulated by soil compaction or irrigation to a depth of 30 cm, in both the fine sand and organic soils, suggesting better soil water supply in compacted than in loosened soils. Soil compaction increased root diameters more in fine sand than it did in organic soil. Most of the root length in loosened soils (fine sand 90%, organic soil 80%) and compacted soils (fine sand 80%, organic soil 75%) was composed of roots with diameters of approximately 0.15 mm. With respect to dry weight, length, surface area and volume of the fibrous root system, all the measurements gave significant resposes to irrigation and soil compaction. Total root volumes in the 0–50 cm of soil were 4.3 cm³ and 9.8 cm³ in loosened fine sand and organic soils, respectively, and 6.7 cm³ and 13.4 cm³ in compacted sand and organic soils, respectively. In fine sand, irrigation increased the volume from 4.8 to 6.3 cm³.     

Plasma extravasation through neuronal stimulation in human nasal mucosa in the setting of allergic rhinitis

Sanico, Alvin M., Satsuki Atsuta, David Proud, and AlkisTogias. Plasma extravasation through neuronal stimulation in humannasal mucosa in the setting of allergic rhinitis. J. Appl. Physiol. 84(2): 537-543, 1998.We havepreviously shown that capsaicin nasal challenge in subjects withallergic rhinitis produces a dose-dependent increase in the albumincontent of nasal lavage fluids. In the present set of studies, wedetermined whether this observation represents plasma extravasationthat is neuronally mediated. To evaluate whether glandular secretionscontribute to the albumin increase in nasal lavage fluids, volunteerswith allergic rhinitis were pretreated with atropine or placebo before capsaicin challenge. Atropine significantly reduced the volume ofreturned lavage fluids and their lysozyme content but increased theiralbumin and fibrinogen content. To assess the contribution of sensorynerve stimulation, subjects with allergic rhinitis were pretreated in asecond study with lidocaine or placebo before capsaicin challenge.Lidocaine significantly attenuated the capsaicin-induced increases inthe volume of nasal lavage fluids, as well as their lysozyme andalbumin content. To rule out the possibility of a direct effect oflidocaine on blood vessels rather than on nerves, healthy subjects werepretreated in a third study with lidocaine or placebo before bradykininnasal challenge. Lidocaine did not affect the bradykinin-inducedincrease in the albumin content of nasal fluids. We conclude that, inallergic rhinitis, high-dose capsaicin induces plasma extravasation inthe human nose and that this effect is neuronally mediated. Thisprovides more definitive evidence that neurogenic inflammation canoccur in vivo in the human upper airway.

     

Clara cell: Progenitor for the bronchiolar epithelium

Clara cells were first described as a morphologically distinct cell type by Kolliker in 1881, but they take their name from the seminal study of human and rabbit bronchioles by Max Clara in 1937. Since their discovery, Clara cells have been identified as central players in protecting the airway from environmental exposures. The diverse functions of Clara cells in lung homeostasis include roles in xenobiotic metabolism, immune system regulation, and progenitor cell activity. Recent identification of a sub-population of Clara cells as a bronchiolar tissue-specific stem cell and a potential tumor initiating cell has focused the attention of cell and molecular biologists on the Clara cell and its behavior under normal and disease conditions.     

Post-Operative Plasma Osteopontin Predicts Distant Metastasis in Human Colorectal Cancer

BackgroundThe overall prognosis of colorectal cancer (CRC) patients is unsatisfactory due to cancer metastasis after operation. This study aims to investigate the clinical significance of plasma osteopontin (OPN) levels as minimally invasive, predictive, and surrogate biomarkers for prognosis of CRC patients.MethodsThis randomized study design consists of pre-operative and post-operative plasma samples from a total of 79 patients. We determined plasma levels of OPN by ELISA and examined their correlation with the clinicopathological parameters of CRC patients. The effects of endogenous and exogenous OPN on CRC metastasis were investigated by examination of the effect on regulators of epithelial to messenchymal transition and migration assay.ResultsOur findings demonstrated for the first time the clinical correlation of plasma OPN with metastasis of CRC patients. High post-operative plasma OPN level (>153.02 ng/ml) associated with development of metastasis after curative resection (p<0.001). Moreover, post-operative plasma OPN level correlated with disease-free survival of CRC patients (p=0.009) and was an independent factor for predicting development of metastasis in CRC patients after curative resection (p=0.036). Our in vitro model showed that OPN ectopic expression induced DLD1 cell migration through Snail and Twist1 overexpression and E-cadherin repression, and secretory OPN level enhanced cell migration.ConclusionsThe results of the current study suggest that post-operative plasma OPN correlated with post-operative metastasis, suggesting that it is a potential non-invasive biomarker for the development of future metastasis in CRC patients. In addition, OPN was shown to be involved in the metastatic process and thus inhibition of OPN is a potential therapeutic approach to treat CRC patients.     

Circulating Bacterial-Derived DNA Fragment Level Is a Strong Predictor of Cardiovascular Disease in Peritoneal Dialysis Patients

BackgroundCirculating bacterial DNA fragment is related to systemic inflammatory state in peritoneal dialysis (PD) patients. We hypothesize that plasma bacterial DNA level predicts cardiovascular events in new PD patients.MethodsWe measured plasma bacterial DNA level in 191 new PD patients, who were then followed for at least a year for the development of cardiovascular event, hospitalization, and patient survival.ResultsThe average age was 59.3 ± 11.8 years; plasma bacterial DNA level 34.9 ± 1.5 cycles; average follow up 23.2 ± 9.7 months. At 24 months, the event-free survival was 86.1%, 69.8%, 55.4% and 30.8% for plasma bacterial DNA level quartiles I, II, III and IV, respectively (p < 0.0001). After adjusting for confounders, plasma bacterial DNA level, baseline residual renal function and malnutrition-inflammation score were independent predictors of composite cardiovascular end-point; each doubling in plasma bacterial DNA level confers a 26.9% (95% confidence interval, 13.0 – 42.5%) excess in risk. Plasma bacterial DNA also correlated with the number of hospital admission (r = -0.379, p < 0.0001) and duration of hospitalization for cardiovascular reasons (r = -0.386, p < 0.0001). Plasma bacterial DNA level did not correlate with baseline arterial pulse wave velocity (PWV), but with the change in carotid-radial PWV in one year (r = -0.238, p = 0.005).ConclusionsCirculating bacterial DNA fragment level is a strong predictor of cardiovascular event, need of hospitalization, as well as the progressive change in arterial stiffness in new PD patients.     

Radio Frequency-Activated Nanoliposomes for Controlled Combination Drug Delivery

This work was conducted in order to design, characterize, and evaluate stable liposomes containing the hydrophobic drug raloxifene HCl (RAL) and hydrophilic doxycycline HCl (DOX), two potentially synergistic agents for treating osteoporosis and other bone lesions, in conjunction with a radio frequency-induced, hydrophobic magnetic nanoparticle-dependent triggering mechanism for drug release. Both drugs were successfully incorporated into liposomes by lipid film hydration, although combination drug loading compromised liposome stability. Liposome stability was improved by reducing the drug load and by including Pluronics® (PL) in the formulations. DOX did not appear to interact with the phospholipid membranes comprising the liposomes, and its release was maximized in the presence of radio frequency (RF) heating. In contrast, differential scanning calorimetry (DSC) and phosphorus-31 nuclear magnetic resonance (³¹P-NMR) analysis revealed that RAL developed strong interactions with the phospholipid membranes, most notably with lipid phosphate head groups, resulting in significant changes in membrane thermodynamics. Likewise, RAL release from liposomes was minimal, even in the presence of RF heating. These studies may offer useful insights into the design and optimization of multidrug containing liposomes. The effects of RAL on liposome characteristics and drug release performance underscore the importance of appropriate physical-chemical analysis in order to identify and characterize drug-lipid interactions that may profoundly affect liposome properties and performance early in the formulation development process.KEY WORDS: controlled release, drug combination, liposomes, nanoparticles     

Positively-Charged Semi-Tunnel Is a Structural and Surface Characteristic of Polyphosphate-Binding Proteins: An In-Silico Study

Phosphate is essential for all major life processes, especially energy metabolism and signal transduction. A linear phosphate polymer, polyphosphate (polyP), linked by high-energy phosphoanhydride bonds, can interact with various proteins, playing important roles as an energy source and regulatory factor. However, polyP-binding structures are largely unknown. Here we proposed a putative polyP binding site, a positively-charged semi-tunnel (PCST), identified by surface electrostatics analyses in polyP kinases (PPKs) and many other polyP-related proteins. We found that the PCSTs in varied proteins were folded in different secondary structure compositions. Molecular docking calculations revealed a significant value for binding affinity to polyP in PCST-containing proteins. Utilizing the PCST identified in the β subunit of PPK3, we predicted the potential polyP-binding domain of PPK3. The discovery of this feature facilitates future searches for polyP-binding proteins and discovery of the mechanisms for polyP-binding activities. This should greatly enhance the understanding of the many physiological functions of protein-bound polyP and the involvement of polyP and polyP-binding proteins in various human diseases.     

Growth and Development in Chinese Pre-Schoolers with Picky Eating Behaviour: A Cross-Sectional Study

Objective

To explore the associations between picky eating behaviour and pre-schoolers’ growth and development. Corresponding potential mechanisms, such as nutrient and food subgroup intake, as well as micronutrients in the blood, will be considered.

Methods

Picky eating behaviour was present if it was reported by parents. From various areas of China, 937 healthy children of 3-7 years old were recruited using a multi-stage stratified cluster sampling method. Children and their mothers’ socio-demographic information and children’s anthropometry, intelligence, blood samples, one 24-hour dietary intake record and food frequency questionnaire were collected. Z-scores and intelligence tests were used to evaluate growth and development (cognitive development). Multilevel models were employed to verify the associations between picky eating behaviour and growth and development.

Results

The prevalence of picky eating as reported by parents was 54% in pre-schoolers. Compared with the non-picky eaters, weight for age in picky eaters was 0.14 z-score (95% CI: -0.25, -0.02; p = 0.017) lower while no significant difference was found in intelligence (p > 0.05). Picky eating behaviour lasting over two years was associated with lower weight for age, as was nit-picking meat (the prevalence from parents’ perception was 23% in picky eaters) (p < 0.05). Picky eaters consumed fewer cereals, vegetables, and fish (p < 0.05), and had a lower dietary intake of protein, dietary fibre, iron, and zinc (p < 0.05). There were no differences in the concentrations of essential minerals in whole blood (p > 0.05).

Conclusions

Picky eating behaviour is reported by parents in half of the Chinese pre-schoolers, which is negatively associated with growth (weight for age). Lower protein and dietary fibre as well as lower iron and zinc intakes were associated with picky eating as were lower intakes of vegetables, fish and cereals.