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Biomedical subjects

D Danon

Publications and source records attributed to D Danon.

At least 37 records · Page 2Linked to original sources
PubMed1985

Changes of cell shape and surface charge topography in ATP-depleted human red blood cells.

ATP depletion crenates human red blood cells. With ferritin-avidin (FA) and cationized ferritin (CF) cell surface labeling, it is demonstrated that the discocyte----crenated shape transformation alters the two-dimensional topography of negative charge sites. With restoration of ATP levels, cell shape and charge topography return to normal. Concurrent changes in red cell shape and surface charge topography can be explained by associations between membrane integral proteins and the red cell cytoskeleton.

Adenosine Triphosphate↗
PubMed1985

Promotion of wound healing by yeast glucan evaluated on single animals.

The effectiveness of yeast glucan in the acceleration of wound healing was evaluated in mice, rats and guinea pigs. In all experiments comparison between glucan treatment in one hind leg and saline treatment as control on the other leg was made on identical wounds. The degree of healing in the two legs was evaluated macroscopically and classified as follows: 1. healing more advanced in glucan treated wound marked by (+). 2. No significant difference between the two legs marked by (0). 3. Healing more advanced in the control wound, marked by (-). During the days when the differences were most obvious, 60% to 80% of the animals showed more advanced healing in the glucan treated wound, 20% to 40% showed no significant difference; and 0 to 15% showed more advanced healing in the control, saline treated wound. The average time for complete wound healing was reduced by about 18% as a result of glucan treatment. The histological analysis shows that the acceleration of wound healing was mediated by early arrival of macrophages to the wound area in the glucan treated wounds.

Animals↗
PubMed1980

Separation of human spermatozoa from a single ejaculate into various age-groups.

Ejaculated human spermatozoa were separated into various age-groups on the basis of their different specific gravity. Salt-poor 25% human serum albumin was used as a separation medium. The separation process had no detectable harmful effect on the spermatozoa. The motility and penetration abilities of the separated cell fractions were tested by means of a new method using a fragiligraph. The younger group of spermatozoa demonstrated better motility and penetration ability in comparison with the older age-groups.

Adult↗
PubMed1979

Phagocytosis of nucleated and mature beta thalassaemic red blood cells by mouse macrophages in vitro.

Physiological or experimental decrease in sialic acid (SA) content on the red blood cell (RBC) membrane is believed to play an important role in the recognition of these cells by macrophages. Since there is a 20-30% decrease in the SA content on the membrane of thalassaemic RBC, the interaction between macrophages and these RBC was studied in vitro. Using mouse peritoneal macrophages, it was found that these macrophages 'recognize' and phagocytize thalassaemic RBC while RBC from normal donors are hardly phagocytized. The average level of phagocytosis of thalassaemic RBC from splenectomized patients was found to be 22-fold higher than that of RBC from normal donors. The phagocytized cells consisted of both mature and nucleated RBC. Mouse peritoneal macrophages seem to be a useful in vitro system for the study of the accelerated sequestration and shortened life span of thalassaemic RBC.

Animals↗
PubMed1979

Surface charge characteristics of cells from malignant cell lines and normal cell lines of the human hematopoietic system.

Cells from malignant and normal lines of human hematopoietic origin were studied for their surface charge characteristics with the use of the following criteria: 1) the electron microscopic appearance of cell membranes after labeling with cationized ferritin (CF) either before or after glutaraldehyde fixation, 2) electrophoretic mobility, 3) total sialic acid content, and 4) agglutinability with poly-L-lysine (PLL). CF induced a time-dependent redistribution of surface receptors in unfixed malignant cells but not in unfixed normal cells. After 10 seconds of labeling with CF, both normal and malignant unfixed cells showed a uniform and even labeling pattern. After 5 minutes of labeling, malignant cells exhibited a highly pronounced pattern of clusters and patches, as distinct from a random and even pattern exhibited by normal cells. Both normal and malignant cells after fixation exhibited an equivalent random and even labeling pattern with CF, independent of the duration of labeling. The malignant cells studied possessed less sialic acid, had a lower electric mobility, and were agglutinated more readily with PLL than were the normal cells.

B-Lymphocytes↗
PubMed1978

Age-related changes in aortic intima of rats.

The aortic intima of young and old Wistar rats was studied by light and electron microscopy. The endothelial cells of young rats are flat and regular and lie adjacent to the internal elastic lamina (IEL). Endothelial cells of old rats have irregular shapes and sizes and bulge into the lumen. Long protrusions connect these cells to the IEL through a layer of granular and fibrillar material that separates the IEL from the endothelium. This material is PAS and Alcian blue positive and increases with age. There are twice as many pinocytic vesicles on the luminal front of endothelial cells of old rats as compared to the tissue front. Endothelial cells of young rats have similar numbers of vesicles on the two fronts. No significant difference was found between the charge density of the luninal plasmalemma of young and old rats; however, significantly less sialyl groups were found on endothelial cells of old rats. A marked difference in the labeling pattern of the IEL by cationized ferritin (CF) was observed between young and old rats.

Age Factors↗
PubMed1978

Neutrophilic turnover rate in human age groups evaluated by serum lysozyme activity.

Serum lysozyme activity was determined in 135 healthy people classified into five different age groups ranging from 20 to 90 years. A turbidometric method with egg-white lysozyme as standard enzyme using the Fragiligraphy for automatic recording of the serum lysozyme was used. The results show a progressive increase in serum lysozyme activity with age. In the oldest age group of 60-90 years, the increase in serum lysozyme was more than that expected for the diminished glomerular filtration rate in old age. Since the serum level of lysozyme can reflect the rate of neutrophilic turnover, it can be assumed that this rate increases above the age of 60.

Adult↗
PubMed1977

Phagocytosis of 'old' red blood cells by macrophages from syngeneic mice in vitro.

We have studied in vitro the interaction of peritoneal macrophages with 'old' and 'young' RBC, as well as with enzymatically treated 'old' and 'young' RBC from syngeneic mice. 'Old' RBC were recognized and phagocytized by macrophages, whereas 'young' RBC were not. Neuraminidase treatment of both 'young' and 'old' RBC had little effect on the extent of phagocytosis. Trypsin treatment, on the other hand, markedly reduced the phagocytosis of 'old' RBC and had no effect on the phagocytosis of 'young' RBC. The level of phagocytosis of 'old' RBC by macrophages from mineral-oil treated mouse peritoneal cavities was roughly half that of macrophages from untreated mice. It is postualted that 'old' RBC could be recognized due to the presence of cytophilic antibodies on the surface of the macrophages. The specificity of these hypothetical cytophilic antibodies is believed to be directed towards sites which are absent or shielded in 'young' RBC, and exposed in 'old' RBC. Trypsin treatment of 'old' RBC appears to remove these antigenic sites from the 'old' RBC. The lower level of phagocytosis of 'old' RBC by mineral-oil induced macrophages could be due to the previous phagocytic activity of these cells, and their relatively uncoated, newly form plasma membrane, lacking cytophilic antibodies. In support of this hypothesis, we have demonstrated that trypsin treatment of macrophages resulted in a markedly decreased phagocytosis of 'old' RBC.

Animals↗
PubMed1976

A method for automatic recording of serum lysozyme activity with the fragiligraph.

A quick and simple method for the estimation of lysozyme activity using the Fragiligraph, was described. Diminution of turbidity in a suspension of Micrococcus lysodeikticus produced by the addition of standard lysozyme (hen egg white) or serum sample, was continuously recorded for 5 min by the Fragiligraph. The normal mean serum lysozyme activity value obtained by this method is 6,80 mug/ml +/- 1.85.

Autoanalysis↗
PubMed1976

Comparative ultrastructural analysis of two tortoise bladders, Testudo graeca and Geochelone carbonaria.

Urinary bladders from the desert tortoises, Testudo graeca and Geochelone carbonaria were removed at specific times during the year and species in all bladders examined: (1) granular cells, (2) mitochondria-rich cells, and (3) basal cells. Cells analogous to these three types have also been observed in amphibian bladders (from toad Bufo marinus and bullfrog, Rana catesbiana) and reptilian bladders (from Pseudemys scripta and Clemmys caspica). Both tortoises have an incomplete layer of basal cells so that the granular and mitochondria-rich cells extend from the lumen to the basement membrane: something was not observed in bladders from bullfrog or turtles. A flask-shaped light cell was observed in the Geochelone carbonaria bladder obtained in April. No counterpart of this cell was seen in the same species sacrificed in January, or in any of the Testudo graeca bladders, although a similar cell has been described in the turtle, Pseudemys scripta (Rosen, Expt. Molec. Path., 12: 286-296, '70). This study was undertaken to characterize the cell types present in tortoise bladder and to compare them with cell types in the bladder of the turtle, bullfrog and toad.

Animals↗