Human platelet lysate successfully promotes proliferation and subsequent chondrogenic differentiation of adipose-derived stem cells: a comparison with articular chondrocytes.

Fetal calf serum (FCS) bears a potential risk for carrying diseases and eliciting immune reactions. Nevertheless, it still represents the gold standard as medium supplement in cell culture. In the present study, human platelet lysate (PL) was tested as an alternative to FCS for the expansion and subsequent chondrogenic differentiation of human adipose-derived stem cells (ASCs). ASCs were expanded with 10% FCS (group F) or 5% PL (group P). Subsequently, three-dimensional (3D) micromass pellets were created and cultured for 5 weeks in chondrogenic differentiation medium. Additionally, the de- and redifferentiation potential of human articular chondrocytes (HACs) was evaluated and compared to ASCs. Both HACs and ASCs cultured with PL showed strongly enhanced proliferation rates. Redifferentiation of HACs was possible for cells expanded up to 3.3 population doublings (PD). At this stage, PL-expanded HACs demonstrated better redifferentiation potential than FCS-expanded cells. ASCs could also be differentiated following extended passaging. Glycosaminoglycan (GAG) quantification and qRT-PCR of 10 cartilage related markers demonstrated a tendency for increased chondrogenic differentiation of PL-expanded ASCs compared to cells expanded with FCS. Histologically, collagen type II but also collagen type X was mainly present in group P. The present study demonstrates that PL strongly induces proliferation of ASCs, while the chondrogenic differentiation potential is retained. HACs also showed enhanced proliferation and even better redifferentiation when previously expanded with PL. This suggests that PL is superior to FCS as a supplement for the expansion of ASCs and HACs, particularly with regard to chondrogenic (re)differentiation.

[Effect of clothing on sphygmomanometric and oscillometric blood pressure measurement in hypertensive subjects]. / Der Einfluss von Bekleidung auf die sphygmomanometrische und oszillometrische Blutdruckmessung bei Hypertonikern.

BACKGROUND AND OBJECTIVE: The few studies published on this subject have shown that blood pressure measurements give similar results whether the patients' arm is covered by clothing or not. But it has not been clarified whether this is also true in the case of hypertensive persons, Yet, in practice the correct measurement is of critical importance in the diagnosis of hypertension. METHODS: 203 hypertensive patients were examined with the auscultatory sphygmomanometry and the automatic oscillometry by measuring the pressure three times with each method. These tests were carried out in a randomized sequence on a covered arm (the patient's own clothing of maximally 2 mm thickness), the bare arm and the arm covered with a standardized cotton sleeve (2 mm). The auscultatory sphygmomanometry was done blinded (non-sleeved, sleeved, standardized). RESULTS: Calculation of confidence intervals for the mean differences of the three settings (bare, clothing and standard sleeve) and equivalence testing demonstrated that a garment or cloth on the arm under the manometer cuffs did not significantly effect the blood pressure within the predefined interval of equivalence of +/- 4 mm Hg. Thus, measuring blood pressure with the cuff over the person's sleeve does not significantly effect the result. CONCLUSION: This study shows that measuring blood pressure in hypertensive persons with or without a cloth sleeve (maximally 2 mm thick) does not result in any statistically significant difference. This simplifies the blood pressure measurement that have to be taken frequently on hypertensive persons.