Transient glucose intolerance during attacks of thyrotoxic periodic paralysis

In a 19-year-old Japanese male (case 1) with thyrotoxic periodic paralysis (TPP), an increase of plasma glucose concentration together with abnormally high levels of serum immunoreactive insulin (IRI) was observed preceding a spontaneous attack of paralysis. Therefore, the plasma glucose, glucagon, epinephrine, norepinephrine, serum IRI, growth hormone and cortisol levels, and the erythrocyte insulin receptors were measured in case 1 and a 40-year-old Japanese male (case 2) with TPP during attacks of paralysis induced by prolonged glucose loading. In case 1, the serum IRI concentration was elevated to the extraordinarily high level of 655.0 microU/ml at the beginning of paralysis, and at that time, the plasma glucose concentration was 147 mg/dl. However, when paralysis was not induced by a similar glucose loading during methimazole treatment, the serum IRI and plasma glucose levels at the corresponding time after glucose loading were 20.9 microU/ml and 87 mg/dl, respectively. Furthermore, the affinity of the erythrocyte insulin receptors was decreased during the attack. In case 2, plasma glucose and serum IRI concentrations were increased in accordance with the initiation of paralysis although the blood levels of hormones counteracting insulin were not significantly changed. These findings suggest that there is something interacting with the normal action of the insulin in the early phase of paralysis.     

Glucosylation of esculetin by plant cell suspension cultures

Cell suspension cultures of Lithospermum erythrorhizon, Gardenia jasminoides and Nicotiana tabacum were capable of glucosylating esculetin to esculin (7-hydroxycoumarin-6-O--D-glucoside). Especially, a culture strain of Lithospermum erythrorhizon was superior in the esculetin glucosylating capability; 40 to 50% of esculetin administered to the culture medium at early stationary growth stage was converted into esculin within 24 h. The rate of glucosylation was also dependent on the growth stage and the medium composition especially growth hormones and sugar.     

Hormonal regulation of berberine production in cell suspension cultures of Thalictrum minus

Effects of auxin and cytokinin on cell growth and alkaloid production in cell suspension cultures of Thalictrum minus were examined in an attempt to increase the productivity of a medicinal compound, berberine. In Linsmaier and Skoog medium containing auxin such as 2,4-D (1 M), the cultured cells grew rapidly, producing little berberine. On the other hand, the berberine-producing activity was remarkably enhanced by simultaneous administration of auxin and cytokinin, although cell growth was inferior. In particular, for the combination of NAA (60 M) and 6-benzylaminopurine (10 M), the yield of berberine was as high as 20 mg/30 ml medium after 2 weeks of culture. Furthermore, most of the berberine produced by the cells was released into the liquid medium, in which an excess of berberine crystallized. The results of the present experiments are suggestive of an advantage in adopting a two-stage culture method for the production of berberine in fermentor systems.Abbreviations LS Linsmaier and Skoog - 2,4-D 2,4-dichlorophenoxyacetic acid - NAA 1-naphthaleneacetic acid - IAA indole-3-acetic acid - IBA indole-3-butyric acid - BAP 6-benzylaminopurine     

Enzymatic difference between laticifers and cultured cells of papaya

Cell suspension cultures of Carica papaya were found to produce a papain-like enzyme showing an amidase activity similar to papain. Experiments suggested that the enzyme was an SH-enzyme, but an immunological test indicated the absence of papain in cultured cells. The isoelectric point (4.3) of the enzyme of cultured cells was the same as that of the leaf extract, but was different from that of papain or other amidases in the latex of the fruit.     

Effect of dietary fiber, glucomannan, on absorption of sulfonylurea in man

In order to clarify whether a dietary fiber has any effect upon the intestinal absorption of sulfonylurea, changes in plasma concentration of glibenclamide were determined during a six-hour period in nine healthy volunteers who took 2.5 mg of glibenclamide together with a breakfast and 3.9 g of glucomannan in a form of konjac powder and were compared with those of the control experiment in which the same amount of the hypoglycemic agent was given without the dietary fiber. In the control, mean plasma glibenclamide level increased rapidly, reaching a peak at 60 min and decreased gradually thereafter, whereas an increase in plasma glibenclamide level was blunted in the test experiment, thus plasma concentration of glibenclamide being lower at 30, 60, 90 and 150 min compared with the corresponding value of the control (31.7 +/- 24.5 ng/ml vs 76.4 +/- 25.0 ng/ml at 30 min; 51.3 +/- 35.5 ng/ml vs 120.9 +/- 56.0 ng/ml at 60 min; 60.0 +/- 38.8 ng/ml vs 117.4 +/- 53.1 ng/ml at 90 min; 54.0 +/- 31.5 ng/ml vs 100.7 +/- 46.5 ng/ml at 150 min). Mean plasma glucose concentration was significantly lower at 30 min in the test experiment than in the control despite the lower level of plasma glibenclamide in the former. The results suggest that glucomannan may influence the intestinal absorption of glibenclamide. A dietary fiber must be prescribed in due consideration of these facts.     

Energy-requiring uptake of protoberberine alkaloids by cultured cells ofThalictrum flavum

Cultured cells ofThalictrum flavum take up berberine exogenously added to medium against the concentration gradient. This uptake was temperature-dependent and sensitive to plasma membrane-bound ATPase inhibitors such as sodium orthovanadate and diethylstilbestrol, indicating that the process is mediated by an energy-requiring system. The time-course of pH-shift during berberine uptake suggests the participation of a berberine-proton antiport system in the berberine uptake by the cultured cells. In addition, the existence of a specific transport system was suggested by the competitive inhibition of berberine uptake by berberine analogues, coptisine and jatrorrhizine.     

Effect of oxygen supply on berberine production in cell suspension cultures and immobilized cells ofThalictrum minus

The ample supply of O₂ proved to be of great importance for berberine production in cell suspension culture ofThalictrum minus, as the specific O₂ consumption rate of berberine-producing cells was twice as high as that of non-producing cells. Furthermore, berberine yield increased with increases in the volumetric O₂ transfer coefficient (K_La). Estimation of the optimum conditions of oxygen supply in suspension cultures and immobilized cells according to a known theoretical model assuming O₂ uptake by cells to be a zero-order reaction was in good agreement with the experimental data. The O₂ supply to immobilized cells could be improved by reducing the cell density and radius of the bead.     

Buried seed populations on the volcano Mt. Usu,northern Japan,ten years after the 1977–78 eruptions

In 1987, a study on buried seed populations was conducted in the crater basin of Mt. Usu, a volcano located in northern Japan, where the vegetation had beeen almost completely destroyed by eruptions in 1977 and 1978. The former vegetation had consisted of grassland and broad-leaved forest. In the areas formerly occupied by this grassland and forest, 2128.0 and 1985.3 seeds per square meter, respectively, were extracted from 12 blocks of the former topsoil using a floattion method. This revealed that many seeds were still viable even after ten years of burial under thick volcanic deposits. The seeds were distributed more in sandy soil than in rocky soil of the former topsoil. Twenty-five species, most of which favored grassland, were detected in both the former grassland and forest. From comparison of α-and β-diversities between the grassland and forest, the structure of the buried seed population was considered likely to have been more diverse in the forest than in the grassland. The determinants of composition of the buried seed populations were discussed with reference to the former vegetation and soil characteristics.     

Contribution of buried seeds to revegetation after eruptions of the volcano Usu,Northern Japan

Soon after the 1977–78 eruptions of the volcano Usu, there were created many gullies in which former topsoil, i.e., well-developed soil accumulated before the eruptions, was eroded in the crater basin, whereas the outside of the gully was covered with thick volcanic deposits. The short-dispersal-seed plants were the most abundant in the inside of gully where the former topsoil was exposed, however, they have not immigrated from external environments. The germination tests of the seeds extracted from the former topsoil demonstrated that viable seeds were buried at 1683.3/m² for 9 years after the eruptions. At least, 12 herbaceous species, e.g.,Rumex obtusifolius, Geum macrophyllum var.sachalinense andPoa annua, were derived from the buried seeds in the former topsoil. Their contribution to revegetation was estimated to be 40.0% in the inside of gully where the former topsoil was exposed in 1983, suggesting that buried seeds are one of the most important seed source for revegetation even in the case of a volcano which produced pumice and ash by eruption.