The Effects of Magnesium Deficiency on Molybdenum Metabolism in Rats

Our previous report indicated that magnesium (Mg) deficiency increased molybdenum (Mo) concentration in the rat liver, suggesting the possibility that Mg deficiency affects Mo metabolism. Growing male rats were given a control diet or a Mg-deficient diet for 4 weeks. Urine and feces were collected during the second and fourth weeks of the feeding trial. The liver, kidney, spleen, skeletal muscle, and blood were collected at the end of the feeding trial. Mg deficiency did not affect the apparent absorption of Mo, but it reduced urinary excretion of Mo. The retention of Mo tended to be higher in the Mg-deficient group than in the control group. Hepatic Mo concentration was higher in the Mg-deficient group than in the control group, but Mg deficiency did not affect Mo concentration in other tissues and plasma. Mg deficiency downregulated the mRNA expression of Mo transporter 2 (MOT2) in the liver, but not in the kidney. These results suggest that Mg deficiency decreases urinary Mo excretion, which is too slight to affect plasma Mo concentration, and that Mg deficiency selectively disturbs the homeostatic mechanism of Mo in the liver, which is not related to the mRNA expression of MOT2 in the liver.     

Macerating Activity of Streptomyces fradiae IFO 3439

Streptomyces fradiae IFO 3439 elaborated enzymes with macerating activity toward various plant tissues. The optimum pH of the macerating activity was about 8.0 when the crude enzyme preparation acted on disks of potato tuber or pieces of Ganpi (Wikstroemia sikokiana Fr. et Sav.) bark. Pectolytic activities in this preparation toward free pectin or poly-galacturonic acid were considerably lower than those of fungi or bacteria. However, when the crude enzyme preparation acted on native pectin in Ganpi bark, about 90 per cent of the galacturonic acid residues were recovered as the polygalacturonides having a still high degree of polymerization. These results suggested that the crude enzyme of S. fradiae solubilized Ganpi pectin, degrading it to only a very small extent.     

The Presence of Two Cd-Binding Components in the Roots of Water Hyacinth Cultivated in a Cd2+-Containing Medium

To find why water hyacinth accumulates the toxic heavy metalion Cd²⁺, the plant was cultivated in a mineral medium supplementedwith Cd²⁺. Cd accumulated in the roots against the concentrationgradient, mostly as a soluble form in the cytoplasm. Chromatographywith Sephadex G-25 and G-50 columns showed that the accumulatedCd was present in two forms with mol wt of 2,300 and 3,000.The components carrying Cd showed a high ratio of absorbanceat 254 nm to that at 280 nm, which suggests that they resemblemammalian Cd-thioneins. These components were not detected inthe roots of water hyacinth cultivated in the absence of Cd²⁺,indicating that they are formed in response to the Cd²⁺ supplement. (Received September 6, 1984; Accepted November 30, 1984)     

Vascular endothelial growth factor in patients with high-altitude pulmonary edema.

To examine the role of VEGF in the pathogenesis of high-altitude pulmonary edema (HAPE), we measured the concentrations of VEGF in venous serum and bronchoalveolar lavage fluid in patients with HAPE and in healthy volunteers. The VEGF in venous serum of the patients was normal at admission and significantly increased at recovery. Similarly, the VEGF in bronchoalveolar lavage fluid of the patients was increased at recovery compared with admission, but values at both admission and recovery were significantly lower than those of the controls. The present finding suggests that VEGF probably is destroyed in the lung of HAPE, and it appears less likely to have a critical part in the pathogenesis of HAPE but has rather an important role in the repair process for the impaired cell layer.     

The micronucleus test of methyl methanesulfonate with mouse peripheral blood reticulocytes using acridine orange-coated slides.

The usefulness of the micronucleus assay using mouse peripheral blood erythrocytes and acridine orange (AO)-coated slides was evaluated with methyl methanesulfonate (MMS). The micronucleus test was carried out at doses ranging from 20 to 80 mg/kg body weight in CD-1 mice by intraperitoneal injection. Peripheral blood cells were examined from 0 to 72 h after treatment at 12- or 24-h intervals. Bone marrow cells from other mice treated with 80 mg/kg MMS were also sampled at the same times. The frequency of micronucleated reticulocytes (MNRETs) increased dose-dependently at every sampling time except 72 h, and the maximum frequency of MNRETs was observed at about 36 h after treatment. Micronucleated polychromatic erythrocytes (MNPCEs) in bone marrow after a dose of 80 mg/kg were significantly induced at 12 h to 36 h, and the maximum frequency of MNPCEs was observed at 24 h after treatment. The induction of MNRETs was delayed by about 12 h compared to that of MNPCEs in bone marrow, and the maximum frequencies of MNRETs were lower than those of MNPCEs, but the induction of MNRETs by MMS was significant and dose-dependent. It is concluded, therefore, that bone marrow cells could be replaced by peripheral blood cells as material for the micronucleus assay using AO-coated slides.     

Observation of delivery behavior in the rhesus monkey

Seven deliveries of rhesus monkeys maintained in the laboratory were recorded by a video recorder system to determine the signs of impending labor. The characteristic postures; i.e., standing, squatting and crouching, were demonstrated in all cases with cyclic regularity (about 2–4 min) 35–210 min prior to the actual parturition, although prediction of the delivery date several days beforehand failed. The four stages of the delivery process are also presented in this report.