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Biomedical subjects

M Kuramochi

Publications and source records attributed to M Kuramochi.

158 records · Page 9Linked to original sources

Regional distribution of immunoreactive endothelin in rats.

By use of a specific radioimmunoassay for endothelin (ET), the regional distribution of ET-like immunoreactivity (LI) was studied in rats. The antiserum used cross-reacted equally with synthetic porcine and rat ET. Significant amounts of ET-LI are detectable not only in aorta, but also in kidney, lung, heart, liver and central nervous system. Gel chromatography of the tissue extracts revealed size heterogeneity of ET-LI; one major component eluting close to, but slightly larger than standard rat ET and the other minor component with a larger molecular weight. These data indicate that ET-LI is widely distributed throughout the various rat tissues, suggesting its possible involvement in a variety of organ functions.

Animals↗

Evaluation of albumin loss during low-density lipoprotein apheresis.

Because the reduced plasma oncotic pressure from hypoproteinemia causes hyperlipidemia, serum albumin levels should be maintained during low-density lipoprotein (LDL) apheresis. The amount of albumin loss was evaluated in seven patients with familial hypercholesterolemia during LDL apheresis in which columns packed with dextran sulfate-cellulose beads were used as a selective adsorbent of LDL. Serum albumin level significantly decreased from 4.3 +/- 0.3 (mean +/- SD) g/dl to 3.6 +/- 0.2 g/dl. The albumin loss was assessed by two different methods: 1) radioimmunoassay of microalbumin content in the discarded fluid, and 2) measurement of changes in plasma albumin reserve. The albumin losses during one apheresis session were 3.7 +/- 2.9 g and 8.3 +/- 5.7 g, respectively, depending upon which of two different methods was used. There was a significant correlation between these two methods (r = 0.84, p less than 0.02). The amount of albumin loss during apheresis was estimated to be between 4.1% and 9.1% of total plasma albumin reserve, and more than half of the decreased serum albumin level appeared to be attributable to dilution due to the electrolyte solution used for priming of the extracorporeal circuit.

Adult↗

Effect of dietary sodium on platelet alpha 2-adrenergic receptors in essential hypertension.

To study the aggregation, adhesion, and specific binding of an alpha 2-antagonist, [3H]rauwolscine, to the platelet membrane fractions, platelets were obtained from 30 patients with essential hypertension and nine normotensive subjects fed a high sodium diet (NaCl, 16-18 g/day) for 7 days and thereafter a low sodium diet (NaCl, 1-3 g/day) for 7 days. The patients with essential hypertension were classified as either salt responders (all those who had greater than 7% decrease in mean arterial pressure from the high to low sodium period) or salt nonresponders (all others). In salt responders, the number of alpha 2-adrenergic receptors on platelet membrane fraction was increased from 523.4 +/- 55.4 fmol/mg of protein in the high sodium period to 669.4 +/- 84.0 fmol/mg of protein in the low sodium period (p less than 0.01), whereas it did not change in salt nonresponders. In contrast, the epinephrine-induced platelet aggregation through alpha 2-adrenergic receptors was decreased in nonresponders, from 47.3 +/- 7.4% in the high sodium period to 24.5 +/- 9.3% in the low sodium period (p less than 0.05), while it did not change in responders. No significant change in the number of alpha 2-adrenergic receptors or epinephrine-induced platelet aggregation was observed in the normotensive subjects.

Blood Platelets↗

The micronucleus test with mouse peripheral blood on N-methyl-N'-nitro-N-nitrosoguanidine and mitomycin C.

The micronucleus test using mouse peripheral blood was conducted with N-methyl-N'-nitro-N-nitro-soguanidine (MNNG) and mitomycin C (MMC) as part of the 5th collaborative study supported by the Environmental Mutagen Society of Japan (CSGMT/MMS.JEMS). Male CD-1 mice were intraperitoneally injected once with 12.5-100 mg/kg of MMC. Peripheral blood was drawn at different intervals after treatment, placed on slides previously coated with acridine orange and the numbers of reticulocytes with micronuclei (MNRETs) were scored. The experiments indicated that the maximum effect of both MNNG and MMC was found about 48 h after treatment, and that the micronucleus test using peripheral blood is useful for the screening of chemicals throughout the experimental period in a single animal.

Animals↗

Effect of nafamostat mesilate on bradykinin generation during low-density lipoprotein apheresis using a dextran sulfate cellulose column.

The dextran sulfate (DS) cellulose column usually used for low-density lipoprotein (LDL) apheresis, is an activator of the contact phase of intrinsic coagulation pathway. Hageman factor (factor XII), high-molecular-weight kininogen (HMWK) and prekallikrein (PK) form a complex on the surface of this activator, and bradykinin is released from HMWK by the action of kallikrein converted from PK. Heparin, a frequently used anticoagulant, has no effect on this process, whereas a protease inhibitor, nafamostat mesilate (FUT-175) is thought to inhibit the process. Five patients with severe hypercholesterolemia were treated with LDL apheresis using heparin or FUT-175, each on a different day. During treatment with heparin, factor XII, HMWK, and PK were markedly decreased by passing through the DS column. A distinct generation of bradykinin was observed by passing through the DS column, which led to an increase of blood bradykinin levels from 12.5 +/- 5.3(Mean +/- SEM) pg/ml to 127.3 +/- 67.1 pg/ml after 1000 ml plasma treatment. FUT-175 almost completely suppressed this bradykinin generation. Because bradykinin generated during LDL apheresis seems to have some vasodilative effect, FUT-175 might be preferred in cases with unstable hemodynamics, although this presumption remains to be demonstrated.

Adult↗