Improving the success rate of human corneal endothelial cell cultures from single donor corneas with stabilization medium.

Main objective of this study was to improve the success rate of human corneal endothelial cell (hCEC) cultures from single donor corneas. We could show that the use of stabilization medium prior to cell isolation may have a positive effect on the success rate of hCEC cultures from single research-grade donor corneas by allowing growth of otherwise possibly not successful cultures and by improving their proliferative rate. hCEC were obtained from corneo-scleral rims of 7 discarded human research-grade cornea pairs. The Descemet membrane-endothelium (DM-EC) sheets of each pair were assigned to 2 experimental conditions: (1) immediate cell isolation after peeling, and (2) storage of the DM-EC sheet in a growth factor-depleted culture medium (i.e. stabilization medium) for up to 6 days prior to cell isolation. hCEC isolated by enzymatic digestion were then induced to proliferate on pre-coated culture plates. The success rate of primary cultures established from single donor corneas were higher for DM-EC sheets kept in stabilization medium before cell isolation. All cultures (7/7) initiated from stabilized DM-EC sheets were able to proliferate up to the third passage, while only 4 out of 7 cultures initiated from freshly peeled DM-EC sheets reached the third passage. In addition, for the 4 successful paired cultures we observed a faster growth rate if the DM-EC sheet was pre-stabilized prior to cell isolation (13.8 ± 1.8 vs 18.5 ± 1.5 days, P < 0.05). Expression of the phenotypical markers Na+/K+-ATPase and ZO-1 could be shown for the stabilized cultures that successfully proliferated up to the third passage.

What does the future hold for the treatment of Fuchs endothelial dystrophy; will 'keratoplasty' still be a valid procedure?

Fuchs endothelial corneal dystrophy (FECD) is a well recognized corneal disorder characterized by the presence of collagenous warts extending from Descemet membrane (guttae) and endothelial cellular dysfunction due to cell loss and/or degeneration. Because of the characteristic abnormal cell morphology as seen with specular microscopy as well as the limited regenerative capacity in vivo, the endothelial cells were considered to be 'dystrophic'. Hence, FECD is commonly managed by replacement of the endothelium with donor tissue by means of a penetrating or endothelial keratoplasty. The latter procedure has now been refined to the isolated transplantation of a donor Descemet membrane and its endothelium, referred to as Descemet membrane endothelial keratoplasty (DMEK). Unexpectedly, clinical observation made after DMEK seemed to challenge the current concept of the state of the endothelium in FECD; we actually observed an important role for the 'dystrophic' host endothelium in re-endothelialization of the denuded DM, and subsequent corneal clearance. In addition, recent studies regarding the pathophysiology of FECD made us realize that the endothelial cells are not 'dystrophic' per se, but in the course of time may have acquired a dysfunction instead. This paper describes the rationale behind this new concept and based on this, discusses the possibilities for future, less invasive treatment modalities for FECD.

Novel polyurethanes with interconnected porous structure induce in vivo tissue remodeling and accompanied vascularization.

Tissue engineering and regenerative medicine have furnished a vast range of modalities to treat either damaged tissue or loss of soft tissue or its function. In most approaches, a temporary porous scaffold is required to support tissue regeneration. The scaffold should be designed such that the turnover synchronizes with tissue remodeling and regeneration at the implant site. Segmented polyester urethanes (PUs) used in this study were based on epsilon-caprolactone (CL) and co-monomers D,L-lactide (D,L-L) and gamma-butyrolactone (BL), and 1,4-butanediisocyanate (BDI). In vitro, the PUs were nontoxic and haemocompatible. To test in vivo biocompatibility, the PUs were further processed into porous structures and subcutaneously implanted in rats for a period up to 21 days. Tissue remodeling and scaffold turnover was associated with a mild tissue response. The tissue response was characterized by extensive vascularization through the interconnected pores, with low numbers of macrophages on the edges and stroma formation inside the pores of the implants. The tissue ingrowth appeared to be related to the extent of microphase separation of the PUs and foam morphology. By day 21, all of the PU implants were highly vascularized, confirming the pores were interconnected. Degradation of P(CL/D,L-L)-PU was observed at this time, whereas the other two PU types remained intact. The robust method reported here of manufacturing and processing, good mechanical properties, and in vivo tissue response of the porous P(CL/D,L-L)-PU and PBCL-PU makes them excellent candidates as biomaterials with an application for soft tissue remodeling, for example, for cardiovascular regeneration.

Limits for the central production of Theta+ and Xi(--)pentaquarks in 920-GeV pA collisions.

We have searched for Theta+(1540) and Xi(--)(1862) pentaquark candidates in proton-induced reactions on C, Ti, and W targets at midrapidity and square root of s = 41.6 GeV. In 2 x 10(8) inelastic events we find no evidence for narrow (sigma approximately 5 MeV) signals in the Theta+ --> pK0(S) and Xi(--) --> Xi- pi- channels; our 95% C.L. upper limits (UL) for the inclusive production cross section times branching fraction B dsigma/dy/(y approximately 0) are (4-16) mub/N for a Theta+ mass between 1521 and 1555 MeV, and 2.5 mub/N for the Xi(--). The UL of the yield ratio of Theta+/Lambda(1520) < (3-12)% is significantly lower than model predictions. Our UL of B Xi(--)/Xi(1530)0 < 4% is at variance with the results that have provided the first evidence for the Xi(--).

Music therapy for people with dementia.

BACKGROUND: Dementia is a clinical syndrome with a number of different causes which is characterised by deterioration in cognitive functions. Research is pursuing a variety of promising findings for the treatment of dementia. Pharmacological interventions are available but have limited ability to treat many of the syndrome's features. Little research has been directed towards non-pharmacological treatments. In this review the evidence for music therapy as a treatment is examined. OBJECTIVES: To assess the effects of music therapy in the treatment of behavioural, social, cognitive and emotional problems of older people with dementia. SEARCH STRATEGY: The Cochrane Dementia and Cognitive Improvement Group (CDCIG) Specialised Register was searched on 30 June 2003 using the term "music*". This Register contains records from all major health care databases and many ongoing trial databases and is updated regularly. The principal reviewer conducted additional searches to retrieve randomised controlled trials (RCTs) concerning the effect of music therapy on older people with dementia. SELECTION CRITERIA: Randomised controlled trials that reported clinically relevant outcomes associated with music therapy in treatment of behavioural, social, cognitive and emotional problems of older people with dementia. DATA COLLECTION AND ANALYSIS: Two reviewers screened retrieved studies independently for methodological quality using a checklist. Data from accepted studies were independently extracted by the reviewers. MAIN RESULTS: Five studies were included. The methodological quality of the studies was generally poor and the study results could not be validated or pooled for further analyses. REVIEWERS' CONCLUSIONS: The methodological quality and the reporting of the included studies were too poor to draw any useful conclusions.