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Biomedical subjects

M Steinhardt

Publications and source records attributed to M Steinhardt.

At least 55 records · Page 3Linked to original sources
PubMed1985

Effect of donor age on clonal differentiation of human skin fibroblasts in vitro.

Human skin fibroblasts of about the same population doubling level, derived from donors of different age, were cloned. After 14 days of growth, the clones were morphologically classified, and cell counts were performed. Significant differences between the three age groups (infant, young adult, old adult) examined concerned the percentual clone type distribution. The size of a single clone depended on the clone type referring to the differentiation level of the cells in all age groups.

Adult↗
PubMed1983

[Cell culture as an experimental system for studying aging processes].

The investigation of cellular aging has mainly been limited by experimental and descriptive work on two separate cell culture systems. On one hand studies were performed on in vitro aging, comparing fibroblasts in early and late passage. On the other hand, fibroblasts derived from donors of different age were compared (in vivo aging). Recently, results have been achieved, stating that some of the investigated parameters change similarly in both systems. Therefore it is of great importance to find criteria for cellular aging, not only to precise the results in both cell culture systems, but also to be able to draw conclusions concerning aging of the organism in vivo.

Aging↗
PubMed1982

[Reference values of hemoglobin content, hematocrit and mean concentration of corpuscular hemoglobin of calves reared without iron supplementation. 3. Comparison of the observed age dependency with literature values].

The average hemoglobin (Hb) and hematocrit (Hc) values determined in our own investigations with 491 rearing calves in the first five months of their lives were compared with the nationally and internationally published data of the dependence of these hematologic values on the age or rearing resp. milk fattening calves. The main influencing factors on the ageing development were the initial level of Hb and Hc, the length of the milk feeding period, the time of the beginning of feed supplementing, the development of dry matter consumption resp. the supply with milk, the iron content of the milk exchanger and the live weight increase achieved under the respective nutritional conditions. This dependence on the development proves that anaemia occurring with rearing calves in the first few weeks of their lives is mainly caused by iron deficiency. From the similarity of the average Hb resp. Hc values one can derive the conclusion that the considerable anaemia frequencies observed in one's investigations are not a phenomenon specific of one farm or of time but represent a general problem of the rearing of calves without iron substitution.

Anemia, Hypochromic↗
PubMed1981

[Reference values of hemoglobin content, the hematocrit and mean concentration of corpuscular hemoglobin in rearing calves without iron substitution. 2. Dependence on live weight and age].

The hamoglobin content (Hb), the hematocrit (Hc) resp. the mean corpuscular hemoglobin concentration (MCHC) were determined resp. calculated of the blood samples (1 to 6 per animal) taken from 491 rearing calves during the first 23 weeks of their lives. Hb, Hc and MCHC were graphed as arithmetic means with standard deviation, as quartiles and as frequency distributions on an interval scale in dependence on live weight (20 ... 160 kg) resp. age (1 ... 161 days). It follows that the period of development from birth up to 28 days of keeping in the weaning area of the rearing farm, up to an age of 63 days resp. a live weight of 80 kg must, under the reference conditions, be considered the minimal period in which the supply of iron covering the needs by iron intervention in the whole stock of calves seems advisable.

Age Factors↗