A growth-promoting factor existing on the body surface of rats

Effects of water-soluble matter adhering to rat hairs on fibroblasts were examined. The dialysate of the wash water of rat hairs significantly enhanced the cell proliferation of both diploid human dermal fibroblasts (DHDF) and diploid rat fibroblasts (DRDF). The cell growth-promoting activity was partially purified by a gel filtration column chromatography. The activity permeates through a ultrafiltration membrane (M.W. cut off: 500). Analyses of its chemical nature show that it is soluble in water, dimethyl sulfoxide or acetonitrile, insoluble in other organic solvents examined, stable to heat or pH shock, and resistant to a bacterial protease.     

Interleukin-1 inhibits the secretion of gastric acid in rats: possible involvement of prostaglandin

To examine the hypothesis that interleukin-1 may inhibit the secretion of gastric acid, the present study was carried out using pylorusligated rats. Based upon three lines of evidence, we report here that interleukin-1, both endogenously released and exogenously administered, suppresses gastric acid secretion and that the interleukin-1-induced inhibition of acid output is possibly mediated by prostaglandin. First, lipopolysaccharide, a potent stimulant of the release and production of endogenous interleukin-1, caused the suppression of gastric acid, and this response was dose-related. Second, the intraperitoneal injection of interleukin-1 resulted in a dose-related inhibition of gastric acid output. Third, the administration of indomethacin completely blocked the suppression of gastric acid secretion induced by interleukin-1. These results demonstrated for the first time that IL-1 might be involved in the regulation of gastric secretion.     

Complementation study of peroxisome-deficient disorders by immunofluorescence staining and characterization of fused cells

Summary Genetic heterogeneity in peroxisome-deficient disorders, including Zellweger's cerebrohepatorenal syndrome, neonatal adrenoleukodystrophy and infantile Refsum disease, was investigated. Fibroblasts from 17 patients were fused using polyethylene glycol, cultivated on cover slips, and the formation of peroxisomes in the fused cells was visualized by immunofluorescence staining, using anti-human catalase IgG. Two distinct staining patterns were observed: (1) peroxisomes appeared in the majority of multinucleated cells, and (2) practically no peroxisomes were identified. Single step 12-(1-pyrene) dodecanoic acid/ultraviolet (P12/UV)-selection confirmed that the former groups were resistant to this selection, most of the surviving cells contained abundant peroxisomes, and the latter cells died. In the complementary matching, [1^-14C]lignoceric acid oxidation and the biosynthesis of peroxisomal proteins were also normalized. Five complementation groups were identified. Group A: Zellweger syndrome and infantile Refsum disease; Groups B, C and D: Zellweger syndrome; Group E: Zellweger syndrome, neonatal adrenoleukodystrophy and infantile Refsum disease. We compared these groupings with those of Roscher and identified eight complementation groups. There was no obvious relation between complementation groups and clinical phenotypes. These results indicate that the transport, intracellular processing and function of peroxisomal proteins were normalized in the complementary matching and that at least eight different genes are involved in the formation of normal peroxisomes and in the transport of peroxisomal enzymes.     

A male-specific renal cytochrome P-450 isozyme(s) responsible for mutagenic activation of 3-methoxy-4-aminoazobenzene in mice

Renal microsomes from male mice (BALB/c, DBA/2 and BALB/c x DBA/2 F1) showed about 10-fold greater activity for mediating mutagenic activation of 3-methoxy-4-aminoazobenzene (3-MeO-AAB) toward Salmonella typhimurium TA98 than did the corresponding hepatic microsomes, as compared on the basis of nmol of microsomal cytochrome P-450. On the other hand, female renal microsomes and other extrahepatic microsomes (lung, small intestine and colon) in both sexes of mice showed little or no activity for converting 3-MeO-AAB to mutagen(s). The mutagenic activation of 3-MeO-AAB with the male renal enzyme(s) was definitely inhibited by cytochrome P-450 inhibitors, 7,8-benzoflavone and SKF 525A. All these findings suggest that in mice, there is a male-specific renal 3-MeO-AAB activation enzyme(s), a cytochrome P-450 isozyme(s), which is different, at least in proportion and/or in nature, from hepatic cytochrome P-450 isozymes.     

An attempt to differentiate further between microglia and fluorescent granular perithelial (FGP) cells by their capacity to incorporate exogenous protein

It seems established that under pathological conditions, microglia and blood monocytes (invading the cerebral parenchyma) behave as histiocytic cells in the central nervous system. However, it has not been clear whether or not phagocytic cells are present in normal cerebral tissue. Recently, we found a new type of cell having an uptake capacity for exogenous substance at the bifurcations of small cerebral vessels except for capillaries. According to Imamoto et al. (1982), ameboid microglia, a kind of precursor of microglia, appear at a perinatal stage and can incorporate exogenous material. In the present paper, the developmental sequences of ameboid microglia and the unique cells laden with fluorescent granules are compared at a light and electron-microscopic level. From this study, it is clear that ameboid microglia are already present in the corpus callosum at 5 days after birth and are potent in their uptake capacity for horseradish peroxidase (HRP). However, at 2 weeks, they transform into star cells and the capacity for incorporation diminishes markedly. The finding is also supported by the quantitative analysis of transformation of ameboid microglia. At 3 months, glial cells do not take the administered HRP under the present conditions. On the other hand, fluorescent granular perithelial (FGP) cells arise from a leptomeningeal tissue (pia mater) and become situated in the perivascular spaces. They are not clearly defined at 5 days, and their uptake capacity for HRP has not yet developed. At 2 weeks, the FGP cells take definite forms with several inclusion bodies, and their uptake capacity for HRP attains a certain degree. Often, they are located at bifurcations of small blood vessels. At 3 months, the FGP cells differentiate completely in appearance, and their pinocytotic capacity reaches a high level. Consequently, the FGP cells belong to a different type of cell from that of ameboid microglia in their developmental sequences and assume a principal role of scavenging waste products in normal cerebral tissue.     

Chronotoxicity of Sodium Valproate and Its Mechanisms in Mice: Dose-Concentration-Response Relationship

A significant circadian rhythm of acute toxicity was demonstrated in mice with intraperitoneal (i.p.) injection of sodium valproate (VPA). The role of pharmacokinetics on the rhythms of the toxicity and electroshock seizure (ES) threshold was investigated. ICR male mice, housed under a light-dark (12 :12) cycle, were injected intraperitoneally 1200 mg/kg for the acute toxicity study and 300 mg/kg for the anticonvulsant effect study. In the acute toxicity, the highest mortality was found when VPA was injected at 1700 and the lowest at 0900 or 0100. The time course of mean plasma and brain VPA concentrations after an injection of VPA was not different between mice injected at 1700 and mice injected at 0100. In the anticonvulsant effect, no significant circadian rhythm was demonstrated for both the ES threshold and the plasma VPA concentrations after i.p. Injection, although a significant rhythm has been reported for them after oral administration. The results suggest that the circadian rhythm in the mortality after an i.p. Injection of VPA may be due to the rhythm in the sensitivity of the central nervous system to the drug and that the mechanism underlying the rhythm of VPA acute toxicity is different from that of the anticonvulsant action of VPA. The route and the time of drug administration are essentially important to study the anticonvulsant effect and acute toxicity of VPA in mice.     

Differentiation of germ cells in seminiferous tubules transplanted to testes of germ cell-deficient mice of W/Wv and Sl/Sld genotypes

(WB X C57BL/6)F1-W/Wv (hereafter, WBB6F1-W/Wv) mice and (WC X C57BL/6)F1-Sl/Sld (hereafter, WCB6F1-Sl/Sld) mice are sterile due to the deficient spermatogenesis in the testes. The cause of deficient spermatogenesis in WBB6F1-W/Wv mice is considered to be a defect in germ cells themselves, whereas that in WCB6F1-Sl/Sld mice is considered to be a defect in tissue environment necessary for differentiation of germ cells. Seminiferous tubules isolated from cryptorchid testes of C57BL/6- +/+ mice were transplanted into the testes of WBB6F1-W/Wv and WCB6F1-Sl/Sld mice to clarify that the extratubular environment of these mice was intact or not. Type A spermatogonia in the transplanted tubules normally differentiated into spermatids, suggesting that the extratubular environment is intact in both WBB6F1-W/Wv and WCB6F1-Sl/Sld mice.     

Entrapment of lipase in silica glass by the sol-gel method and its esterification activity in organic media

Summary Silica glass-entrapped lipase was prepared by the sol-gel method using tetramethoxysilane, and its esterification activity in n-hexane was examined for isoamylbutyrate formation. The hydrogel preparation containing a large amount of water exhibited enough activity. Although the activity of xerogel-entrapped lipase drastically decreased probably due to shrinkage of the gel matrix, the lyophilized gel retained much higher activity than the air-dried gel.     

Human high-affinity FcγRI (CD64) gene mapped to chromosome 1q21.2-q21.3 by fluorescence in situ hybridization

The human FcRI gene encodes for a highaffinity Fc receptor that plays pivotal roles in the immune response. We have used fluorescence in situ hybridization analysis to localize the FcRI gene to human chromosome 1. The human FcRI (CD64) gene has been assigned to human chromosome 1q21.2-q21.3 using R-banded human (pro)metaphase chromosomes.