Search PubMed⌕ Search

Biomedical subjects

D Danon

Publications and source records attributed to D Danon.

117 records · Page 7Linked to original sources
PubMedDate not supplied

Rabbit erythrocyte survival following diminished sialic acid and ATP depletion.

The limited deformability and ATP depletion was considered by some authors to be the factor limiting the life span of old red blood cells (RBC) in circulation. Others believed that sialic acid on the RBC surface determines their life span. We compared the life span of 51Cr labelled, neuraminidase treated rabbit RBCs with ATP depleted by incubation at 37 degree C rabbit RBCs. Osmotic fragility, agglutinability, glucose-6-phosphate dehydrogenase (G6PD) and hexokinase activity and ATP levels of these cells were determined. Desyalated RBCs were removed from the circulation within 24 hours. ATP levels, G6d and hexokinase activity and osmotic fragility were normal in these cells. The agglutination by poly(L-lysine) was affected by the loss of surface charge on these cells. Half the ATP depleted RBCs were out of the circulation within three days. Reconstitution of ATP by reincubation with adenosine, elevated the ATP levels to about 80% of their original level, but survival of these cells did not improve. Analysis of sialic acid showed tha 50% of it was removed during the incubation for ATP depletion. The low ATP level and loss of sialic acid fromt he RBC membrane appeared to be conincidental rather than dependent on each other. The latter appears to be a primary factor in red cell survival.

Adenosine Triphosphate↗
PubMedDate not supplied

Surface charge and flow properties of endothelial membranes in aging rats.

The morphological features, surface charge and fluid properties of the membranes of aortic endothelial cells of young and old Wistar rats were studied by electron microscopy. Remarkable structural changes in the endothelial cells and subendothelial layer were observed in the aorta of old rats, due to accumulation of fibrillar and granular substances and cellular debris. Analysis of the possible age-related alterations in the permeability properties of the aortic endothelium indicated that positively charged macromolecules such as cationized ferritin are more rapidly transported through the endothelium of old rat aorta, as compared to young rats, thereby leading to their accumulation in the aortic intima of the old animal. Cytochemical analyses of the charge properties of endothelial cell membranes revealed that despite the general similarity in the anionic site density and distribution, endothelial cells from old rat aorta are characterized by a significant decrease in the density of cell-surface sialic acids. The ability of anionic sites in the luminal front of the endothelial cells to redistribute reversibly by lateral migration under the influence of multivalent ligands was shown to be an important factor in the mechanism of internalization and transport of cationized ferritin through the endothelial barrier. It was therefore suggested that the local changes in the surface charge properties due to an interaction with positively charged substances, may account for the accumulation of plasma components in the blood vessel intima of the old animals.

Aging↗
PubMedDate not supplied

Relationship of hematological variables to learning performance in aged Fischer-344 rats.

The relationship between hematological variables and the ability to perform behaviorally in two learning tests was evaluated in male F344 rats aged 22-24 months. Rats were screened for ability to meet criterion for learning one-way active avoidance in a straight runway task. Rats failing to meet criterion were given no further testing and were assigned to Group 1 (G1). Rats meeting criterion were tested in a 14-unit T-maze (2 days, 10 trials/day). Failure to negotiate the T-maze within 600 s on any three trials resulted in assignment to Group 2 (G2) with no further testing. Rats successfully completing both tasks constituted Group 3 (G3). Trunk blood was collected following behavioral testing and was assayed to determine red blood cell count (RBC), hematocrit (HCT), hemoglobin (HGB), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), white blood cell count (WBC), bands (BND), polymorphs (POLY), lymphocytes (LYM), monocytes (MON), and eosinophils (EOS). The combined G1/G2 group had significantly lower RBC, HCT, HGB, and EOS but significantly higher MCV and MCH than G3 rats. Correlation analysis revealed a positive relationship of group membership (i.e., learning test completion) to RBC, HCT, HGB, and EOS, but a negative correlation of group membership to MCH. No significant correlation emerged between any hematological characteristic and performance in either behavioral task. These results suggest that a simple blood test to determine HCT may be a useful screen for removal of moribund rats from aging studies attempting to control for effects of health on behavioral performance in rodent models.

Aging↗
PubMedDate not supplied

Treatment of human ulcers by application of macrophages prepared from a blood unit.

Decubital ulcers contribute to morbidity and mortality in elderly patients. Macrophages play a major role in the process of wound healing. We compared the efficacy of local treatment of decubital ulcers in elderly patients using macrophages prepared from a blood unit, vs. conventional treatments. Patients with decubital ulcers (n = 199) hospitalized during one year in a Geriatric Hospital in Israel, were included in the study. The ulcers of 72 patients (average age 82), who provided informed consent, by themselves or by family, were treated by local injection of macrophages prepared from a blood unit in a closed sterile system. The remaining 127 patients (average age 79) were treated conventionally and served as controls. No exclusion criteria were applied. Only a completely healed ulcer was considered a positive outcome of treatment. In the macrophage-treated group 27% (36 out of 131 ulcers) were healed compared to 6% (15 out of 248) in the control group (p < 0.001). There was also a significantly faster healing in the experimental group (p < 0.02). No side effects were noted. We conclude that Macrophages prepared from a blood unit, in cost-effective, closed, sterile system, are significantly more effective than conventional methods for the treatment of ulcers in elderly patients.

Administration, Topical↗