Zinc deficiency is associated with suppression of colonocyte proliferation in the distal large bowel of rats

As zinc status may influence susceptibility to colon cancer, we examined the effect of dietary zinc deficiency on the proliferation of epithelial cells (colonocytes) in the large bowel of rats. When compared to feed-restricted rats, those with zinc deficiency showed a significant reduction in proliferation in the distal colon as assessed by accumulated metaphase arrest and crypt cell production rates in vivo. Zinc deficiency had no apparent effect on thymidine kinase activity in colonocytes but was accompanied by minor changes in fecal mass and fecal pH. In rats, zinc deficiency is associated with a reduction in the rate of proliferation of colonocytes in the distal colon.     

LG4–5 domains of laminin‐211 binds α‐Dystroglycan to allow myotube attachment and prevent anoikis

Poly(2‐hydroxyethyl methacrylate) (PolyHEMA) prevents cell attachment was used here to study anoikis, the process where cells die when unattached or attached to an inappropriate matrix, in mouse C₂C₁₂ myotubes. A method was developed to efficiently embed proteins into PolyHEMA and the effect on cultured myotubes was determined. Myotubes grown on PolyHEMA‐coated plates fail to attach to the surface and remain as rounded, suspended cells, undergo dramatic increases in apoptosis and necrosis, and the number of viable cells decreases. Incorporation of merosin (laminin‐211) or the short laminin globular (LG4–5) modules of the laminin‐α2 chain C‐terminus (called 2E3) that binds α‐dystroglycan diminishes both apoptosis and necrosis and increases viability while bovine serum albumin had a much lesser effect, showing the specificity of this effect for these matrix proteins. One sarcolemma receptor for laminin‐binding is α‐dystroglycan. An antibody which binds α‐dystroglycan but which does not block laminin‐binding (VIA4) had little effect on apoptosis or viability on merosin or 2E3 embedded plates while another antibody (IIH6) which specifically blocks binding dramatically decreased viability and increased apoptosis. When merosin or 2E3 are added to culture media rather than embedded on plates these can also increase viability and decrease apoptosis even though the cells remain in suspension, though the effect is not as great as found for the embedded proteins where the cells attach. Thus, we conclude that the binding of a small LG4–5 modules of laminin‐211 to α‐dystroglycan is important in preventing anoikis and that attachment plus binding is necessary for maximal cell survival. J. Cell. Physiol. 222:111–119, 2010. © 2009 Wiley‐Liss, Inc.     

Behavioural responses of non-breeding waterbirds to drone approach are associated with flock size and habitat

ABSTRACT

Capsule: Non-breeding waterbirds are more likely to respond to drone approach when in larger flocks, and responses are more likely in arable and coastal habitats than at inland lochs.

Aims: To investigate the extent to which drones are a potential source of disturbance to non-breeding waterbirds.

Methods: Using a commercially available quadcopter drone, we approached waterbird flocks of varying sizes in coastal, freshwater, and arable habitats following a standardized protocol.

Results: Waterbirds at coastal sites and in arable fields were more likely to respond to drone approach than those at inland freshwater bodies. Larger flocks were more likely to respond to drone approach and responded at a greater distance than smaller flocks.

Conclusion: Repeated drone use at coastal and arable sites with large aggregations of feeding or roosting waterbirds could cause energetically costly flight responses, increased stress, and effective loss of available habitat. At such sites, it may be beneficial to regulate recreational and commercial drone use to minimize potential disturbance effects.     

A possible maturation pathway of calicivirus particles

The assembly process of feline calicivirus, a representative member of the Caliciviridae, from subunit components in infected cells was monitored by labelling the virus-specific proteins with 3H-leucine for different periods and harvesting cellular extracts at various phases of infection. A series of protein subunit components was detected and the virus assembly process appeared to have occurred in at least two stages. The first stage involved the very rapid aggregation of precursor polypeptides into 5S subunits which possible through several 'unstable' intermediates formed the stable 15S subunit component. The second stage was the association of 15S subunits with the synthesized viral genomes to form the mature infectious FCV particles which sedimented at 170S. Within 30 min of the initiation of protein synthesis, the process of assembly was complete and mature FCV particles appeared in infected cells.     

Antifungal Dosing in Obesity: A Review of the Literature

Obesity is becoming a global pandemic that is projected to increase significantly over the next few decades. Unfortunately, studies of drug dosing and pharmacokinetics have largely excluded obese patients. Currently, literature inadequately characterizes drug disposition in these patients. Only a limited selection of literature addresses antibacterial dosing in obesity, and virtually none characterizes antifungal dosing in obesity. This review discusses the changes in pharmacokinetics that occur in obesity and the available in vitro and in vivo data describing the disposition of antifungal agents in obese animals and patients.     

Validation of the safety of MDCK cells as a substrate for the production of a cell-derived influenza vaccine

Cell culture-based production methods may assist in meeting increasing demand for seasonal influenza vaccines and developing production flexibility required for addressing influenza pandemics. MDCK-33016PF cells are used in propagation of a cell-based seasonal influenza vaccine (Optaflu^®); but, like most continuous cell lines, can grow in immunocompromised mice to produce tumors. It is, therefore, essential that no residual cells remain within the vaccine, that cell lysates or DNA are not oncogenic, and that the cell substrate does not contain oncogenic viruses or oncogenic DNA. Multiple, redundant processes ensure the safety of influenza vaccines produced in MDCK-33016PF cells. The probability of a residual cell being present in a dose of vaccine is approximately 1 in 10³⁴. Residual MDCK-DNA is ≤10 ng per dose and the ß-propiolactone used to inactivate influenza virus results in reduction of detectable DNA to less than 200 base pairs (bp). Degenerate PCR and specific PCR confirm exclusion of oncogenic viruses. The manufacturing process has been validated for its capacity to remove and inactivate viruses. We conclude that the theoretical risks arising from manufacturing seasonal influenza vaccine using MDCK-33016PF cells are reduced to levels that are effectively zero by the multiple, orthogonal processes used during production.