Summary. Two adults with rapidly progressive acute myeloblastic and myelomonoblastic leukemia were given single injections of tritiated thymidine, and measurements were made of the growth rates of their leukemic and normal hematopoietic cells by radioautographic methods. Although almost all leukemic blasts in both marrow and blood were metabolically active as shown by their ability to incorporate tritiated uridine and leucine in Vitro, only 5.6% and 6.1% ol the blasts in the marrow and even fewer in the blood incorporated tritiated thymidine. The mitotic indexes of the marrow blasts were 0.66% and 0.52%; no circulating blasts were dividing. The mean generation times of the actively proliferating blasts were estimated to be 49 and 83 hours. This cannot be equated with the doubling time of the total leukemic population as there is evidence that many blasts fail to continue dividing and die. The mean durations of the phases of the blasts' mitotic cycles were as follows: DNA synthesis (S) = 22 and 19 hours, premitosis (G2) = 3 hours, mitosis (M) = 0.47 and 0.62 hour (minimal estimates), and postmitosis (G1) = 24 and 61 hours. In both patients the maximal mean transit time of the blasts in the blood was 36 hours, and the minimal numbers of actively dividing blasts present were 1.6 and 2.6 X 109 per kg of body weight.Estimates were also made of the rates of proliferation and maturation of the residual normal erythrocytic and granulocytic cells in these two patients. Although total production was markedly diminished because of reduction in the number of normal elements, the relatively few remaining normal cells appeared to be dividing and maturing at rates that are about the same or only slightly slower than those found in normal subjects.We conclude that the main reason leukemic blasts displace normal hematopoietic precursors in acute leukemia is that the blasts largely fail to differentiate. Many die but many others persist in the marrow and elsewhere as primitive cells and continue to proliferate. As the blasts accumulate, they

Licorice-induced pseudoaldosteronism is a common adverse effect in traditional Japanese Kampo medicine, and 3-monoglucuronyl glycyrrhetinic acid (3MGA) was considered as a causative agent of it. Previously, we found 22α-hydroxy-18β-glycyrrhetyl-3-O-sulfate-30-glucuronide (1), one of the metabolites of glycyrrhizin (GL) in the urine of Eisai hyperbilirubinuria rats (EHBRs) treated with glycyrrhetinic acid (GA), and suggested that it is also a possible causative agent of pseudoaldosteronism. The discovery of 1 also suggested that there might be other metabolites of GA as causal candidates. In this study, we found 22α-hydroxy-18β-glycyrrhetyl-3-O-sulfate (2) and 18β-glycyrrhetyl-3-O-sulfate (3) in EHBRs’ urine. 2 and 3 more strongly inhibited rat type 2 11β-hydroxysteroid dehydrogenase than 1 did in vitro. When EHBRs were orally treated with GA, GA and 1–3 in plasma and 1–3 in urine were detected; the levels of 3MGA were quite low. 2 and 3 were shown to be the substrates of organic anion transporter (OAT) 1 and OAT3. In the plasma of a patient suffering from pseudoaldosteronism with rhabdomyolysis due to licorice, we found 8.6 µM of 3, 1.3 µM of GA, and 87 nM of 2, but 1, GL, and 3MGA were not detected. These findings suggest that 18β-glycyrrhetyl-3-O-sulfate (3) is an alternative causative agent of pseudoaldosteronism, rather than 3MGA and 1.

No abstract

Pseudoaldosteronism is a common adverse effect associated with traditional Japanese Kampo medicines. The pathogenesis is mainly caused by 3-monoglucuronyl glycyrrhetinic acid (3MGA), one of the metabolites of glycyrrhizin (GL) contained in licorice. We developed an anti-3MGA monoclonal antibody (MAb) and an ELISA system to easily detect 3MGA in the plasma and urine of the patients. However, we found that some metabolites of GL cross-reacted with this MAb. Mrp2-deficient Eisai Hyperbilirubinemia rats (EHBRs) were administered glycyrrhetinic acid (GA), and we isolated 22α-hydroxy-18β-glycyrrhetyl-3-O-sulfate-30-glucuronide (1) from the pooled urine with the guidance of positive immunostaining of eastern blot as the new metabolite of GL. The IC50 of 1 for type 2 11β-hydroxysteroid dehydrogenase (11β-HSD2) was 2.0 µM. Similar plasma concentrations of 1 and GA were observed 12 h after oral administration of GA to EHBR. Compound 1 was eliminated via urine, whereas GA was not. In Sprague–Dawley (SD) rats orally treated with GA, compound 1 was absent from both the plasma and the urine. Compound 1 was actively transported into cells via OAT1 and OAT3, whereas GA was not. Compound 1, when produced in Mrp2-deficiency, represents a potential causative agent of pseudoaldosteronism, and might be used as a biomarker to prevent the adverse effect.

The fine structure of the hepatic sinusoids of 81 human embryos and fetuses and their development from 5 to 12 weeks gestation were studied. At 5 weeks gestation, sinusoid‐like structures and Kupffer‐like cells were observed between liver cell cords. Between 6 and 8 weeks gestation the sinuosids were completely developed. Definite Kupffer cells appear at this developmental stage, when the bone marrow has not yet formed. Floating macrophages form cell aggregates in the sinusoids which contact endothelial cells and settle as Kupffer cells. Erythroblastophagia is observed in Kupffer cells and macrophages. The endothelial linings are closed, with the attenuated cell processes and intercellular junctions between the adjoining endothelial cells. No transition was observed between Kupffer cells and endothelial cells. The findings suggest that Kupffer cells in the human embryo are extrahepatic in origin and that they reach the sinusoids via the circulatory system. Ito cells, which store fat, originate from mesenchymal cells in the septum transversum.