High concentration of a gastrin releasing peptide-like immunoreactive substance in pregnant human milk

The level of a gastrin releasing peptide-like immunoreactive substance (GRP-IS) in human milk and plasma during late pregnancy and after delivery was measured. GRP-IS in milk increased during late pregnancy (1.3 nM at 39 weeks) and decreased after delivery (100 pM). GRP-IS in plasma during late pregnancy and after delivery was much lower (below 2 pM). By using HPLC and gel-filtration chromatography, two peaks of GRP-IS were purified. The one was coeluted with GRP (18-27) and the other was a prohormone. The GRP-IS in milk during pregnancy was mostly composed of proGRP. These results suggest that GRP may be produced and secreted in mammary glands.     

The augmentative effect of a protein-bound polysaccharide (PSK) on tumoricidal activity of the soluble factor produced by a streptococcal preparation (OK-432)-activated macrophages

The enhancement of antitumor activities of the tumoricidal soluble factor (SF) from a streptococcal preparation (OK-432)-activated macrophages by the pretreatment with a protein-bound polysaccharide (PSK) was investigated in tumor-bearing mice.Two-step stimulations with OK-432 atin vivo priming andin vitro eliciting were required for the production of the tumoricidal SF by macrophages, and the tumoricidal activity of the SF apparently correlated with the uptake of OK-432 by macrophages at priming phase.Tumoricidal activity of the SF from OK-432-activated macrophages in proteose-peptone (P-P)-pretreated mice significantly decreased with the development of the tumor, whereas in PSK-pretreated mice did not. Pretreatment of tumor-bearing mice with PSK saved a decrease in the macrophages carrying Ia^k or asialo GM1 antigens and an increase in wheat germ agglutinin (WGA) receptors. Furthermore, the uptake of OK-432 by macrophages at priming phase was enhanced. The tumoricidal activity of the SF from OK-432-activated macrophages was augmented.Thus, PSK may restore the depressed functions of macrophages, and the combination therapy with PSK and OK-432 may be effective to enhance the production of tumoricidal SF in tumor-bearing mice.     

Thymidine triphosphate dephosphorylating activity in regenerating rat liver

The enzyme activity of dephosphorylation of thymidine triphosphate was found in microsomal fraction of rat liver. The enzyme activity decreased at the time when [³H]thymidine incorporation into DNA of regenerating liver increased. When the [³H]thymidine incorporation was suppressed by 1,3-diaminopropane, the enzyme activity remained elevated. These results suggest that the enzyme activity appears to be closely linked to DNA synthesis.     

Changes in spatial distribution pattern during the larval stage of the fall webworm,Hyphantria cunea drury (Lepidoptera: Arctiidae)

Summary The changes in spatial distribution pattern during larval stage of the fall webworm,Hyphantria cunea were quantitatively investigated in the field experimental populations. The female adult deposits eggs as a cluster and the hatchlings make a compact colonial-web. In this period, the all-or-none type mortality which is characteristic in gregarious insect species was occasionary recognized before spinning a compact colonial-web. Once making a compact colonial-web, the larvae feed the leaves in the colonial-web up to about 5th instar. In this period, the movement of larvae occurred due to the local food shortage in a colonial-web and the expansion of colonial-web. As the larvae developed, the colonial-web was separated into several small groups. These larvae began to disperse about 5th instar. In this period, the local food shortage seems to be an important trigger for the larval dispersal. The mean concentration of larvae on leaves abruptly decreased, and finally the larvae became solitary at the 6th or 7th instars. The dispersal process in later larval stage is not necessarily due to the complete food shortage. The dispersal prior to the occurrence of food shortage may be a safety mechanism to protect the larvae from the food shortage.     

Effect of glucose on protein phosphorylation in rat pancreatic islets

Isolated rat pancreatic islets, incubated in the presence of extracellular ³²Pi to steady state ³²P incorporation into cellular phosphopeptides, were exposed to glucose for 10 min. Glucose (16.7 mM) significantly stimulated the phosphorylation of six phosphoproteins with molecular weights of 15,000, 35,000, 49,000, 64,000, 93,000 and 138,000. Mannoheptulose (16.7 mM) markedly inhibited glucose-stimulated phosphorylation of these six phosphoproteins. This protein phosphorylation might be important in mediating glucose-stimulated insulin release.     

Topographic examination of sister chromatid differential staining by nomarski interference microscopy and scanning electron microscopy

BrdU-substituted Chinese hamster chromosomes were treated with a hot Na₂HPO₄ solution and stained with Giemsa to produce sister chromatid differential staining (SCD). The process of SCD was examined with the Nomarski differential interference microscope and the scanning electron microscope. After the Na₂HPO₄ treatment alone, unifilarly BrdU-substituted (TB) chromatids appeared somewhat more severely collapsed than the bifilarly substituted (BB) chromatids. Subsequent Giemsa staining, however, brought about pronounced piling up of the Giemsa dye on the TB-chromatids but not on the BB-ones, causing highly distinct differential Giemsa staining as well as a marked differentiation in surface topography between the sister chromatids. Removal of the Giemsa dye from the differentially Giemsa stained chromosomes resulted in a disappearance of such a pronounced topographic differentiation.     

Two opposite types of sister chromatid differential staining in BUdR-substituted chromosomes using tetrasodium salt of EDTA

The direct staining of BUdR-substituted Chinese hamster chromosomes in a 4Na-EDTA-Giemsa solution resulted in a B-dark type of sister chromatid differential staining (SCD) in which bifilarly substituted chromatids stained dark. On the other hand, when BUdR-substituted chromosomes were pretreated with a 4Na-EDTA solution and then stained with Giemsa, a B-light type SCD was obtained in which bifilarly substituted chromatids stained light.     

Characterization of O-trimethylsilyl derivatives of d-glucose,d-galactose,and d-mannose by gas-liquid chromatography-chemical-ionization mass spectrometry with ammonia as reagent gas

The per(trimethylsilyl) ethers of d-glucose, d-galactose, and d-mannose were analyzed by g.l.c.-c.i.m.s. with ammonia as the reagent gas. C.i.m.s. gave simple fragmentation and fragment ions of high intensity in the high-mass range where the QM⁺ ion is also detected. The β-d anomers gave ions at m/e 558 showing intensities 3–12 times those of the α-d anomers. The epimers could be distinguished by differences in the intensities of the ions and by the observation that d-glucose gave a base peak at m/e 198, d-galactose at m/e 468, and d-mannose at m/e 204. The pyranose and furanose structures could be distinguished by comparing the ion intensities at m/e 198, m/e 271, m/e 361, m/e 396, and m/e 451. A similar analysis was also performed with 2-methylpropane as the reagent gas.     

Alpha reduced nicotinamide adenine dinucleotide-dependent reductase reactions of rat liver microsomes.

The kinetics of alpha-NADH-dichlorophenolindophenol (DCPIP) and alpha-NADH-cytochrome c reductase reactions of rat liver microsomes showed that the reactio ns proceeded by a ping-pong mechanism, and that the oxidation of alpha-NADH was the rate-determining reaction. The DCPIP-reducing activity with alpha-NADH in the presence of ADP was about 1% of that with beta-NADH. ADP inhibited the alpha-NADH-DCPIP reductase reaction in a competitive manner with respect to alpha-NADH and a value of 1.2 mM for the inhibition constant was obtained. ADP also inhibited cytochrome b5 reduction with alpha-NADH. More than 90% of cytochrome b5 was reduced under conditions where 90% of the alpha-NADH-DCPIP reductase activity was suppressed with ADP. The reduction of DCPIP with alpha-NADH preceded that of cytochrome b5, but the reductions partly overlapped. From these results, a diversed electron flow from alpha-NADH to cytochrome b5 and electron sharing between cytochrome b5 and DCPIP were indicated. alpha-NAD+ also inhibited the alpha-NADH-DCPIP reductase reaction. Analyses of the inhibition indicated that two types of alpha-NADH-DCPIP reductase reaction existed, one of which was resistant to alpha-NAD+ inhibition. In contrast to the reoxidation of beta-NADH-reduced cytochrome b5, the process was largely monophasic when cytochrome b5 was reduced with alpha-NADH.