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Biomedical subjects

S Usami

Publications and source records attributed to S Usami.

At least 181 records · Page 10Linked to original sources
PubMed1980

[Subacute toxicity study of lentinan in rats. 5-week intravenous treatment (author's transl)].

Male and female JCL : SD rats were treated intravenously with lentinan in 5% mannitol solution at dose levels of 0, 0.03, 3.0 and 30.0 mg/kg/day for 5 weeks. Rats receiving 0.3, 3.0 and 30.0 mg/kg/day showed reddening in ear, tail and scrotum and edema in legs and scrotum after day 3 of treatment. Males receiving 30.0 mg/kg/day gained less body weight than control. Occult blood was found in the urine of rats receiving 30.0 mg/kg/day. With regard to haematology, rats from the treatment groups had low mean values relating to red blood cell count, packed cell volume and haemoglobin, while high white blood cell count were recorded for these rats. Biochemical examinations revealed decreases in albumin level and A/G ratio and increases in beta-globulin and gamma-globulin levels for rats from the treatment groups. Slightly high values of BUN were showed for rats receiving 30.0 mg/kg/day. Organ weight analysis showed dose-dependent increase in the spleen, liver and adrenal. Histopathological changes attributable to treatment included (1) changes in reticuloendothelial system such as proliferation of reticular cells and micronodule of epithelioid cells in the spleen, liver and lymph nodes; (2) arteritis in many organs especially notable in epididymis, intestines and mesentery; (3) haemorrhagic changes in lung, intestines and urinary bladder and secondary changes such as increased chronic nephropathy, hypospermatogenesis, spermatic granuloma in epididymis and granulomatous inflammation in ear, tail and scrotum. The maxim safe dose was estimated to be smaller than 0.03 mg/kg/day for males and 0.03 mg/kg/day for females in the present study.

Animals↗
PubMed1978

Theoretical and experimental studies on viscoelastic properties of erythrocyte membrane.

The deformation of a portion of erythrocyte during aspirational entry into a micropipette has been analyzed on the basis of a constant area deformation of an infinite plane membrane into a cylindrical tube. Consideration of the equilibrium of the membrane at the tip of the pipette has generated the relation between the aspirated length and the dimensionless time during deformational entry as well as during relaxation after the removal of aspiration pressure. Experimental studies on deformation and relaxation of normal human erythrocytes were performed with the use of micropipettes and a video dimension analyzer which allowed the continuous recording of the time-courses. The deformation consisted of an initial rapid phase with a membrane viscosity (range 0.6 x 10(-4) to 4 x 10(-4) dyn.s/cm) varying inversely with the degree of deformation and a later slow phase with a high membrane viscosity (mean 2.06 x 10(-2) dyn.s/cm) which was not correlated with the degree of deformation. The membrane viscosity of the recovery phase after 20 s of deformation (mean 5.44 x 10(-4) dyn.s/cm) was also independent of the degree of deformation. When determined after a short period of deformation (e.g., 2 s), however, membrane viscosity of the recovery phase became lower and agreed with that of the deformation phase. These results suggest that the rheological properties of the membrane can undergo dynamic changes depending on the extent and duration of deformation, reflecting molecular rearrangement in response to membrane strain.

Adult↗
PubMed1975

Deformability of sickle cells as studied by microsieving.

The effect of deoxygenation on deformability of sickle cells (Hb SS RBC) was studied quantitatively by a microsieving technique with the use of polycarbonate filters having micropores of 5 mum in diameter. The rate of pressure rise and the relative resistance during filtration through polycarbonate sieves increased progressively when the P02 of Hb SS RBC suspensions was reduced below 80 mm. Hg. Control studies on Hb AA RBC did not show any significant change in either parameter when deoxygenated. The present study on the filterability of Hb SS RBC and our previous data on the viscometric behavior of Hb SS RBC serve to establish the quantitative relation between P02 and the deformability of Hb SS RBC.

Anemia, Sickle Cell↗