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G Benga

Publications and source records attributed to G Benga.

68 records · Page 4Linked to original sources
PubMedDate not supplied

Decreased water permeability of erythrocyte membranes in patients with Duchenne muscular dystrophy.

The water proton relaxation times of erythrocytes (T'2a) from 15 Duchenne muscular dystrophy (DMD) patients and age-matched controls have been determined by a pulse nuclear magnetic resonance technique. Statistically significant higher values of T'2a were noted for the DMD erythrocytes, both in the presence or absence of p-chloromercuribenzene sulfonate, a potent inhibitor of water diffusion through erythrocyte membrane. As the values of T'2a are inversely related to the water permeability, the results indicate a decreased permeability of erythrocyte membrane in DMD. The findings are discussed in relation to the molecular mechanisms of water diffusion across erythrocyte membrane and in regard to the general problem of membrane abnormalities in DMD.

Adolescent↗
PubMedDate not supplied

On measuring the diffusional water permeability of human red blood cells and ghosts by nuclear magnetic resonance.

The characteristics of water diffusional permeability (P) of human red blood cells were studied on isolated erythrocytes and ghosts by a doping nuclear magnetic resonance technique. In contrast to all previous investigations, systematic measurements were performed on blood samples obtained from a large group of donors. The mean values of P ranged from 2.2 X 10(-3) cm.s-1 at 5 degrees C to 8.1 X 10(-3) cm.s-1 at 42 degrees C. The reasons for some of the discrepancies in the permeability coefficients reported by various authors were found. In order to estimate the basal permeability, the maximal inhibition of water diffusion was induced by exposure of red blood cells to p-chloromercuribenzenesulfonate (PCMBS) under various conditions (concentration, duration, temperature). The lowest values of P were around 1.3 X 10(-3) cm.s-1 at 20 degrees C, 1.6 X 10(-3) cm.s-1 at 25 degrees C, 1.9 X 10(-3) cm.s-1 at 30 degrees C and 3.2 X 10(-3) cm.s-1 at 37 degrees C. The results reported here represent the largest series of determinations of water diffusional permeability of human red blood cells (without or with exposure to mercurials) available in the literature, and consequently the best estimates of the characteristics of this transport process. The values of P can be taken as references for the studies of water permeability in various cells or in pathological conditions.

4-Chloromercuribenzenesulfonate↗
PubMedDate not supplied

Basic studies on gene therapy of human malignant melanoma by use of the human interferon beta gene entrapped in cationic multilamellar liposomes. 1. Morphology and growth rate of six melanoma cell lines used in transfection experiments with the human interferon beta gene.

Six cell lines of human malignant melanoma: A375, A375.2, G361, HMV-1, MM8.1 and WM115 were seeded at densities of 1x10(4) cells/ml, 2 x 10(4) cells/ml or 3 x 10(4) cells/ml of RPMI medium supplemented with 10% fetal calf serum and antibiotics in a humidified atmosphere of 5% CO2 at 37 degrees C. A375 cells were also grown in Dulbecco's minimum Eagle's medium (DMEM medium). The morphology was studied by phase contrast light microscopy. At 4 days after seeding the colonies of A375 cells and HMV-1 cells were oval-shaped, the cells were polyhedrical and were making contact with each other regularly. The remaining cells were scattered, more elongated, and made contact randomly. G361 cells and MM8.1 cells tended to form superposed layers before 100% confluency was achieved. There were great differences in the growth rate and doubling time of melanoma cells. The doubling time in day 1 was short (around 6-12 h) in the case of A375, G361 and HMV-1 cells, longer (around 18 h) in the case of MM8.1 cells and very long (ranging between 26 and 89 h) for A375.2 and WM115 cells. There were also differences in the doubling time of cells as a function of the cell density at seeding. On the other hand, except for MM8.1 cells, there were differences between the doubling time in day 2 compared to day 1.

Cell Count↗
PubMedDate not supplied

ATP-ase activity of mitochondria isolated from needle-biopsy liver samples of diabetic subjects.

ATP-ase activity in mitochondria isolated from liver needle-biopsy samples was measured in 5 diabetics, aged 30-63 years and in 4 control subjects of similar age. The mitochondrial fraction was isolated by differential centrifugation of the homogenate and the ATP-ase activity was determined in the optimal conditions previously described for human liver mitochondria. The basal and Mg-stimulated ATP-ase activities were higher, while the DNP-stimulated ATP-ase activity was lower in diabetics compared to controls. The ratio of DNP-ATP-ase/Mg2+-ATP-ase was between 1-2 in diabetics and above 5 in controls. This pattern of ATP-ase activity in diabetics is indicative of mitochondrial damage. No quantitative changes in the amount of mitochondria isolated from liver (expressed in micrograms mitochondrial protein/mg wet tissue) could be noticed in diabetics compared to controls. Consequently, the alterations of ATP-ase activity is probably reflective of impairments of functional integrity of liver mitochondria in diabetics.

Adenosine Triphosphatases↗