Osteogenic Potential of Human Umbilical Cord Mesenchymal Stem Cells on Coralline Hydroxyapatite/Calcium Carbonate Microparticles.

Coralline hydroxyapatite/calcium carbonate (CHACC) is a biodegradable and osteoconductive bone graft material with promising clinical performance. CHACC has been shown to support proliferation and osteogenic differentiation of human bone marrow mesenchymal stem cells (MSCs) in vitro and demonstrated to work as a functional scaffold for bone formation in vivo. Umbilical cord matrix is a more accessible and abundant tissue source of MSCs, but its osteogenic capacity in comparison to human bone marrow when cultured on CHACC has not yet been demonstrated. In this study, we assessed the osteogenic differentiation capacity of human MSCs, isolated from bone marrow and umbilical cord matrix and characterised by flow cytometry, when cultured on 200-300 µm CHACC granules. The 3D cultures were characterised by brightfield and scanning electron microscopy (SEM). Osteogenic potential was assessed by immunocytochemistry and qPCR for key markers of bone differentiation (alkaline phosphatase, runx2, type I collagen, and osteocalcin). By day 1, the MSCs had enveloped the surface of the CHACC granules to form organoids, and by day 7, cells had proliferated to bridge nearby organoids. Extracellular matrix deposition and osteogenic differentiation were demonstrated by MSCs from both tissue sources at day 21. However, MSCs from bone marrow demonstrated superior osteogenic differentiation capability compared to those from umbilical cord matrix. In conclusion, it is possible to culture and induce osteogenic differentiation of umbilical cord matrix MSCs on CHACC. Further research is required to optimise the osteogenicity of umbilical cord matrix MSCs to release their full potential as a readily available, accessible, and abundant tissue source for bone tissue engineering.

The value of respect in human research ethics: a conceptual analysis and a practical guide.

In order to continue to maintain public trust and confidence in human research, participants must be treated with respect. Researchers and Human Research Ethics Committee members need to be aware that modern considerations of this value include: the need for a valid consenting process, the protection of participants who have their capacity for consent compromised; the promotion of dignity for participants; and the effects that human research may have on cultures and communities. This paper explains the prominence of respect as a value when considering the ethics of human research and provides practical advice for both researchers and Human Research Ethics Committee members in developing respectful research practices.

Biosimulation of drug metabolism--a yeast based model.

Computationally predicting the metabolic fates of drugs is a very complex task which is owed not only to the huge and diverse biochemical network in the living cell, but also to the majority of in vivo transformations that occur through the action of hepatocytes and gastro-intestinal micro-flora. Thus, xenobiotics are metabolised by more than a single cell type. However, the prediction of metabolic fates is definitely a problem worth solving since it would allow facilitate the development of drugs in a way less relying on animal testing. As a first step in this direction, PharmBiosim is being developed, a biosimulation tool which is based on substantial data reduction and on attributing metabolic fates of drug molecules to functional groups and substituents. This approach works with yeast as a model organism and is restricted to drugs that are mainly transformed by enzymes of the central metabolism, especially sugar metabolism. The reason for the latter is that the qualitative functioning of the involved biochemistry is very similar in diverse cell types involved in drug metabolism. Further it allows for using glycolytic oscillations as a tool to quantify interactions of a drug with this metabolic pathway.

[Congenital syphilis despite prenatal screening? An evaluation of 14 cases]. / Konnatale Syphilis trotz Mutterschaftsvorsorge? Eine Evaluierung von 14 Fällen.

BACKGROUND: Congenital syphilis (CS) can be effectively avoided by adequate treatment of the mother during pregnancy. Nevertheless, in recent years, the Robert Koch Institute has reported 6-8 of CS cases per year. The aim of this study was to investigate cases of CS with regard to obstetrical history and results of maternal syphilis serology during pregnancy and postpartum. PATIENTS AND METHODS: Between 1997 and 2001, a total of 14 cases of CS were diagnosed after birth in the Stuttgart laboratory. Information on clinical and serological data obtained during prenatal care and at birth had been provided by the treating gynaecologists and paediatricians. Furthermore, serum samples from 11 of the 14 mothers were investigated at the Stuttgart laboratory after birth and also retrospectively at the Herford laboratory. RESULTS: All mothers presented without clinical signs of syphilis. Delayed prenatal care was observed in 6 out of 14 cases. Eleven of the 14 mothers had a positive treponemal screening test. Treatment was initiated only in two of them. During pregnancy treponemal IgM and cardiolipin antibodies were detected in none of 9 and in 5 of 8 sera of untreated mothers, respectively. In contrast, maternal serum samples investigated after birth were all positive for cardiolipin antibodies and 7 of 10 serum samples were positive for TP IgM antibodies. CONCLUSIONS: Delayed or absent prenatal care and misinterpretation of syphilis serology (or laboratory failures) in the presence of latent syphilis are mostly responsible for the inadequate management of syphilis during pregnancy and thus the occurrence of CS.

Iris angiography and aqueous photofluorometry in normal subjects.

Iris angiography and photofluorometry of the aqueous were performed on 44 normal subjects equally distributed between 15 and 65 years of age. Hemoglobin AIc determinations were performed in 20 of these persons. Leakage from the pupillary margin was present in 20% of the eyes studied. In all cases of leakage, the dye faded quickly after the initial peak concentration. No leakage was observed from radial iris vessels. Photofluorometric readings of the aqueous 60 minutes after injection increased significantly with age. Hemoglobin AIc measurements were observed to correlate significantly with aqueous fluorescein concentration. Both these observations may reflect an altered permeability of biologic membranes associated with aging.

Photogrammetry experiments with a model eye.

Digital photogrammetry was performed on stereophotographs of the optic nerve head of a modified Zeiss model eye in which optic cups of varying depths could be simulated. Experiments were undertaken to determine the impact of both photographic and ocular variables on the photogrammetric measurements of cup depth. The photogrammetric procedure tolerates refocusing, repositioning, and realignment as well as small variations in the geometric position of the camera. Progressive underestimation of cup depth was observed with increasing myopia, while progressive overestimation was noted with increasing hyperopia. High cylindrical errors at axis 90 degrees led to significant errors in cup depth estimates, while high cylindrical errors at axis 180 degrees did not materially affect the accuracy of the analysis. Finally, cup depths were seriously underestimated when the pupil diameter was less than 5.0 mm.