Mark Smith

TECHNIQUES FOR MEASUREMENT OF OXYGEN CONSUMPTION RATES OF HEPATOCYTES DURING ATTACHMENT AND POST-ATTACHMENT

Three techniques for measuring oxygen consumption rate (OCR) of cultured cells relevant to the development of bioartificial liver devices are reported. In an oxystat apparatus, HepG2 cells immobilised on Cytodex 3 microcarriers at a concentration of 106 cells ml-1 had a mean OCR of 0.7 nmol s-1/106 cells. The OCR decreased with increasing cell density, a characteristic previously reported for other cell lines. Rat hepatocytes immobilised on single collagen layers in a flow cell and challenged with ammonia had a mean OCR of 0.59 nmol s-1/106 cells. A novel two-compartment oxystat system was used to determine the OCR of rat hepatocytes during the attachment phase. OCR declined from 1.0 nmol s-1/106 immediately after seeding to 0.7 nmol s-1/106 cells at nine hours. The low OCR for HepG2 reflects loss of certain oxygen dependent metabolic pathways. The OCR measured for rat hepatocytes during and post-attachment are significantly higher than those reported elsewhere and have major implications for the development of bioartificial liver devices.

COMPARISON OF HOLLOW FIBRE MEMBRANES FOR HEPATOCYTE IMMOBILISATION IN BIOREACTORS

Various hollow fibre membranes of polyamide, cellulose and polypropylene were investigated as potential substrata for hepatocyte immobilisation in bioreactors for hybrid liver support systems. Membranes were subjected to a cytocompatibility test in which the attachment and morphology of primary hepatocytes were evaluated. The effect of coating with collagen and fibronectin was also studied. Adequate cell immobilisation was possible on polypropylene and polyamide membranes even without coating. The flattening process of the cells was dependent on the material and the coating. The incorporation of porous polypropylene and polyamide hollow fibres in hybrid liver cell bioreactors and their specific permeability properties could also offer means for cell oxygenation, metabolite distribution and immuno-isolation purposes.

Amino acid metabolism by hepatocytes in a hybrid liver support bioreactor.

The amino acid patterns of medium perfusate in a liver cell bioreactor developed for a hybrid liver support system have been measured. There were considerable changes in the concentrations of glutamic acid, glutamine, alanine, arginine, ornithine and branched chain amino acids during the first 10 days which is indicative of dynamic cellular metabolism. From day 15, steady state conditions of nitrogen metabolism are reflected by stable amino acid turnover. Monitoring of urea, K+, and P-450 activity suggests that hepatocytes have switched to a stable protein synthesis with a general amino acid uptake and keto acid release following cell volume increase

What about the dads? issues and possibilities of working with men from a child and youth care perspective

SUMMARY The importance of fathers in their childrens upbringing is increasingly recognised in child and youth care practice. Yet professional interventions in families often focus on men as problems. The experiences of fathers in community settings are applied to a child and youth care context. Workers are challenged to consider the role fathers play in their childrens lives and how CYC principles might provide a basis for including men in their thinking about their work with children, youth, and their families.

School improvement in the marketplace: the case of residential special schools

Over the past couple of decades, residential special schools in Scotland have faced fundamental changes to the way they operate. This has involved the withdrawal of state funding, a shrinkage of the sector and a situation in which schools now have to sell their services in a market economy in order to survive. This article gives a brief outline of the history and development of residential special education for children considered to be troubled or troublesome. It then draws on an evaluation of one former approved, or List D, school to describe how it managed the transition to the marketplace. Findings from the evaluation are introduced and some implications of these are discussed. It is concluded that the shift from state or local authority funding to private provision may have some advantages. However, it also raises a number of questions as to whether provision for some of society’s most damaged children should be determined by market forces.

Systemic liberation of interleukin- 1β and interleukin-1 receptor antagonist in the perioperative phase of liver transplantation

We measured systemic serum levels of interleukin-1 receptor antagonist (IL-1ra), interleukin-1β (IL-1β), tumor necrosis factor α (TNF-α), and interleukin-6 (IL-6) during the preoperative, anhepatic, and postreperfusional phases up to the 7th postoperative day in 60 patients undergoing orthotopic liver transplantation (LTx). In contrast to IL-1β, IL-1ra, TNF-α, and IL-6 showed a significant elevation in relation to the early phase after reperfusion, while TNF-α displayed a high grade of scatter. In addition, IL-1ra levels were significantly elevated during the anhepatic phase. Maximum serum levels were found at 15 min after reperfusion, 120 min after reperfusion, and on the 1st postoperative day, respectively. Serum levels decreased considerably at 24 h and 7 days after reperfusion. The comparative monitoring of systemic cytokine and cytokine antagonist levels, in particular the liberation of IL-1ra and IL-6 may provide useful parameters for the development of new liver preservation theories for LTx.

A review of bioartificial liver development from an artificial organ engineering perspective

Fulminant hepatic failure (FHF) and acute episodes in chronic liver failure are associated with high mortality [1–3]. Organ transplantation is the only treatment acknowledged to improve patient survival when compared with intensive care [4,5]. There is a shortage of donors worldwide [6–8] resulting in approximately 50% mortality amongst patients awaiting transplants [9]. Furthermore, OLT renders graft recipients dependent upon immunosuppression [10,11]. US hospital charges average

Book Review: Challenging violence in schools: an issue of masculinities

250,000 for liver transplants [12]. It was estimated that in the USA in 1996, there were approximately 1,700 emergency liver transplants with 1,000 patients dying while waiting for a transplant. A further 1,000 patients with FHF or sudden onset of acute liver failure (ALF) were either not listed for transplant or died before being listed [13].

Improved hepatocyte in vitro maintenance in a culture model with woven multicompartment capillary systems: Electron microscopy studies

Teachers, like their charges, enjoy the primordial pleasure of the consumer culture ‘shopping around’. And however much we may exhort the ‘good’ over the ‘goods’ society we are reminded that the informed parental consumer is one who ‘shops around’ for the best buy in schooling. Perhaps the importance accorded to schooling is in compensation for ‘time poverty’, parents buying from others a commodity which they cannot afford themselves. This may, ultimately, be the explanation for the widening gap between generations not having the time.