Pentamethyl-hydroxychromane, vitamin E derivative, inhibits induction of nitric oxide synthase by bacterial lipopolysaccharide

Vitamin E, a lipophilic antioxidant, has effectively inhibited the activation of cytokine-induced nuclear factor kB (NFkB). Since NFkB plays a critical role in the induction of an isoform of nitric oxide synthase (iNOS) gene by lipopolysaccharide (LPS), we investigated the effect of a vitamin E derivative, pentamethyl-hydroxychromane (PMC), which is an extremely potent inhibitor of NFkB activation, on the induction of nitric oxide (NO) synthesis and iNOS mRNA by LPS. PMC inhibited the LPS-stimulated induction of NO production in a concentration-dependent fashion in cultured J774 macrophages and rat vascular smooth muscle cells without evidence of cytotoxicity. However, the addition of PMC to J774 macrophages after the induction of iNOS did not inhibit NO production. Treatment of J774 macrophages with LPS resulted in a significant expression of iNOS mRNA, which was profoundly reduced by PMC. Data suggest that PMC inhibits the induction of iNOS by preventing iNOS gene expression through inhibition of NFkB activation.

The herbal medicine sho-saiko-to induces nitric oxide synthase in rat hepatocytes

We have examined the effects of the herbal medicine sho-saiko-to (SST) on nitric oxide (NO) biosynthesis in rat hepatocytes by measuring the stable end-product nitrite and the mRNA of inducible NO synthase (iNOS). Interferon-gamma (IFN) by itself failed to induce NO synthesis (IFN: 1-1,000 u/ml). SST also did not elicit NO synthesis at concentrations up to 300 micrograms/ml when administered alone, but dose-dependently induced NO production in the presence of IFN. Whereas SST or IFN induced barely detectable levels of iNOS mRNA when administered alone, a combination of SST and IFN markedly induced iNOS mRNA in the cells. SST also modestly increased NO synthesis caused by interleukin-1 or bacterial lipopolysaccharide as a single agent, or in combination with IFN. On the other hand, SST had no effects on the NO synthesis produced by iNOS which were already induced. Thus, we found that SST stimulates cultured hepatocytes to produce NO by inducing iNOS gene expression under appropriate conditions. The capability of SST to induce NO biosynthesis might be related to the therapeutic efficacy of SST on the liver diseases.

Trimeresurus flavoviridis venom gland phospholipase A2 isozymes genes have evolved via accelerated substitutions

As a step towards understanding the structure and function of phospholipases A2 (PLA2s), five cDNAs encoding Trimeresurus flavoviridis venom gland PLA2 isozymes have been sequenced. They revealed that the 5' and 3' untranslated regions are much more homologous than the protein-coding regions and that base substitutions have occurred at similar rates for the three positions of codons in the protein-coding regions. Such novel findings are of great interest from the viewpoint of molecular evolution. To gain a further insight into this evolutional phenomenon, we have isolated and sequenced six T. flavoviridis PLA2 isozyme genes. Each gene consisted of four exons and three introns and encoded protein of 138 amino-acid residues, including the signal sequence of 16 amino-acid residues. The introns were much more homologous than the protein-coding regions of exons except for the signal peptide-coding region of the first exon. The absence of apparent functional role in the introns suggested that the protein-coding regions, except for the signal peptide-coding domains, have evolved at greater substitution rates than introns. The fact that the numbers of nucleotide substitutions per non-synonymous site are close to or larger than the numbers of nucleotide substitutions per synonymous site for relevant pairs of genes revealed that Darwinian-type accelerated substitutions have occurred in the protein-coding regions of exons. This is compatible with the presence of PLA2 species with diverse physiological activities in the venom.

Analysis of the Ras p21/mitogen-activated protein kinase signaling in vitro and in Xenopus oocytes

Ras p21 in the GTP-bound form was shown to act as an upstream activator for mitogen-activated protein (MAP) kinase kinase (MAPKK) and MAP kinase, and Raf-1 was reported to act as a MAPKK kinase. Further, physical association between Ras and Raf-1 was demonstrated. Here we have shown that incubation of Xenopus immature oocyte extracts with Ras enhances the ability of endogenous Raf-1 to activate MAPKK. Moreover, a dominant negative form of Raf-1 blocked the Ras-induced activation of MAPKK and MAP kinase in the extracts, but not the cyclin A-dependent activation of MAP kinase. When the extracts were depleted of 45-kDa MAPKK with polyclonal anti-MAPKK antibody, no activation of MAP kinase occurred even after incubation with Ras. These results suggest that Ras can activate the MAPKK kinase activity of Raf-1 in the extracts and that MAPKK is indispensable for the Ras-induced MAP kinase activation. It is well known that Ras can induce oocyte maturation when injected into immature Xenopus oocytes. Co-injection of Ras with an anti-MAPKK antibody that inhibits the MAPKK activity prevented the Ras-induced germinal vesicle breakdown, suggesting that MAPKK mediates, at least, one of cellular functions of Ras.

Expression and characterization of the alpha 2 subunit of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-selective glutamate receptor channel in a baculovirus system

Using a baculovirus expression vector system, the alpha 2 subunit of the mouse alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-selective glutamate receptor (GluR) channel was expressed in Spodoptera frugiperda insect cells. Immunoblotting using the antibody made to the synthetic peptide corresponding to the C-terminus of GluR alpha 2 and [35S]methionine/[35S]cysteine metabolic radiolabeling revealed the major 102-kDa and the minor 98-kDa protein bands. Metabolic radiolabeling with tunicamycin suggested that the two bands correspond to glycosylated and unglycosylated forms, respectively. The recombinant GluR alpha 2 proteins expressed in insect cells were also identified by immunofluorescence staining. The results of [3H]AMPA binding assay using whole cells suggested that, in infected Sf21 cells, binding sites of the GluR alpha 2 proteins were possibly located on the extracellular side. Scatchard analysis of AMPA binding showed the following parameters: Kd = 16 nM, Bmax = 1.9 x 10(5) binding sites per cell or 1 pmol/mg protein in the total particulate fraction. The ligand binding characteristics of the receptors expressed in insect cells were examined. From the effect of various agonists on [3H]AMPA binding of the receptors expressed in insect cells, the rank order potency of agonists was quisqualate > AMPA > L-glutamate > kainate. Thus, the baculovirus-insect cell expression system provides high-efficiency expression of the receptor sufficient to permit structural and functional analyses.

Spermatogenesis and ultrastructure of a peculiar acrosomal formation in the musk shrew, Suncus murinus

Spermatogenesis and acrosomal formation in the musk shrew, Suncus murinus, were studied by light and transmission electron microscopy. The cycle of the seminiferous epithelium was divided into 13 stages based on the characteristics of acrosomal change and nuclear shape, appearance of meiotic figures, location of spermatids, and period of spermiation. The relative frequencies of stages 1 to 13 were 5.1, 5.9, 10.1, 8.8, 12.5, 11.5, 10.6, 7.9, 6.0, 4.8, 8.9, 3.1 and 4.8, respectively. Additionally, spermatid development was subdivided into 13 steps. Acrosomal formation during spermiogenesis in the musk shrew was quite characteristic. However, in contrast to other mammalian species, the nucleus remained in the middle region of the seminiferous epithelium, and only the acrosome extended towards the basement membrane, beginning at step 7. The extension of the acrosome was conspicuous and reached maximum at step 9. At that time, the tip of the acrosome extended nearly to the basement. The acrosome of maturing spermatids was about 3-fold longer than that of spermatozoa. Thereafter, the acrosome gradually shortened and became flat. The enormous fan-shaped acrosome was completely formed at step 13. The prominent extension and subsequent shortening and flattening of the acrosome in the musk shrew appears to be a unique process to form the enormous fan-shaped acrosome.

[Intra-ocular pressure changes during laparoscopic cholecystectomy]

Intra-ocular pressure (IOP) was measured during laparoscopic cholecystectomy (n = 20) under continuous epidural block and nitrous oxide-oxygen anesthesia. There was a slight but significant increase in IOP and peak airway pressure when the abdominal CO2 insuffration was started, and the IOP recovered to the preoperative level after the postural change to the head-up position. It was not associated with any significant change in mean arterial pressure and end-tidal CO2. In one ocular hypertension case undergoing laparoscopic chorecystectomy and appendectomy, however, there was profound increase in IOP during abdominal CO2 insuffration with head down position. We speculate that it was due to the effect of increased CVP with abdominal CO2 insuffration and postural change on the IOP. Thus the laparoscopic operation with head-down position should be avoided in patients with ocular hypertension.

Purification and characterization of a coagulant enzyme, okinaxobin II, from Trimeresurus okinavensis (himehabu snake) venom which release fibrinopeptides A and B

A coagulant enzyme, okinaxobin I, which was purified from Trimeresurus okinavenis (himehabu snake) venom, released specifically fibrinopeptide B from fibrinogen to form fibrin clots. In the present study, its isozyme denoted as okinaxobin II has been purified to homogeneity from the same venom by chromatographies on Sephadex G-100, CM-Toyopearl 650M, and FPLC Mono-Q columns. Differently from okinaxobin I, okinaxobin II specifically cleaved fibrinopeptides A and B from fibrinogen similarly as found for alpha-thrombin. The enzyme acted on fibrinogen with specific activity of 42 NIH units/mg at optimum pH of 8.0. Okinaxobin II was a monomeric glycoprotein with a mol. wt of 37,500 on SDS-PAGE, which was reduced to 29,500 after treatment with N-glycanase. Okinaxobin II was much more basic (pI = 8.1) than okinaxobin I (pI = 5.4). The N-terminal sequence was highly similar to those of okinaxobin I and some other snake venom coagulant enzymes such as flavoxobin (Trimeresurus flavoviridis), batroxobin (Bothrops atrox and Bothrops moojeni), and catroxobin (Crotalus atrox). Okinaxobin II hydrolyzed tosyl-L-arginine methyl ester and benzoyl-L-arginine p-nitroanilide. The esterase activity was strongly inhibited by diisopropylfluorophosphate and to a lesser extent by tosyl-L-lysine chloromethyl ketone, indicating that the enzyme is a serine protease like alpha-thrombin. In terms of amino acid composition, okinaxobin II was similar to okinaxobin I and dissimilar to alpha-thrombin.

Mutations in the COL4A5 gene in Alport syndrome: a possible mutation in primordial germ cells

Using a combination of gene amplification with single strand conformation polymorphisms analysis and sequencing, we examined the COL4A5 gene in 37 patients with Alport syndrome. In patient A8, a single base insertion was noted at codon 1,597 tyrosine in exon 49. The premature terminal signal appeared and 89 amino acids (approximately one-third) of the non-collagenous domain were lost. The mutation was present in the mother, hence she is heterozygous. In patient A12, the nucleotide changed from C to T at codon 1,679 glutamine in exon 51, which created a termination codon, and 7 amino acids at the carboxyl terminus were lost. Gene tracking using peripheral leukocytes revealed that the parents did not carry the mutant allele, while the sister was heterozygous. DNA samples from hair roots and skin fibroblasts of the mother were normal and immunological examination of the epidermis of the mother indicated that the alpha 5(IV) chain was normally expressed. As these results suggest that somatic cells of the mother do not carry the mutant allele, the primordial germ cells possibly carry a fresh mutation in the mother of patient A12.

[Isolated oculomotor nerve palsy caused by mesencephalic hemorrhage]

A 62-year-old man with a history of diabetes mellitus, hypertension and liver damage has sudden diplopia on Nov. 4, 1992. Ocular movements of this right eye were normal, but his left eyelid was completely ptotic, and left pupil was dilated and nonreactive to light. In primary position, his left eye deviated outward, and could not move to any direction. He was diagnosed as having total oculomotor nerve palsy of the left side without any other neurological signs or symptoms; his consciousness level was alert and mental state was normal. The present case showed normal facial sensation, no facial palsy and no tongue deviation. Deep tendon reflexes were hypoactive bilaterally. Pyramidal tract sign, cerebellar sign, and gait disturbance were not observed. Superficial sensation of the extremity was normal. Brain CT scan revealed a small mesencephalic hemorrhage extending to the tegmentusm ventral to the cerebral aqueduct of the left side. Brain magnetic resonance imaging demonstrated a high-intensity area in the left oculomotor nucleus and its fascicles in the midbrain on T1- and T2-weighted image. The oculomotor nerve palsy of the left eye gradually improved, but mydriasis, adduction impairment and downward gaze palsy continued, and oculomotor nerve palsy of the left eye was compatible with so-called inferior branch palsy of the oculomotor nerve. Moreover, contralateral eye movements were normal except for mild upward gaze palsy. Oculomotor nerve palsy of this type was consistent with the syndrome of oculomotor nucleus described by Pierrot-Deseillingny in 1981. It was presumed that the superior rectus muscle is innervated by the contralateral oculomotor nerve nucleus in man as well as in animals.

A novel mammalian Ras GTPase-activating protein which has phospholipid-binding and Btk homology regions

We have previously purified a novel GTPase-activating protein (GAP) for Ras which is immunologically distinct from the known Ras GAPs, p120GAP and neurofibromin (M. Maekawa, S. Nakamura, and S. Hattori, J. Biol. Chem. 268:22948-22952, 1993). On the basis of the partial amino acid sequence, we have obtained a cDNA which encodes the novel Ras GAP. The predicted protein consists of 847 amino acids whose calculated molecular mass, 96,369 Da, is close to the apparent molecular mass of the novel Ras GAP, 100 kDa. The amino acid sequence shows a high degree of similarity to the entire sequence of the Drosophila melanogaster Gap1 gene. When the catalytic domain of the novel GAP was compared with that of Drosophila Gap1, p120GAP, and neurofibromin, the highest degree of similarity was again observed with Gap1. Thus, we designated this gene Gap1m, a mammalian counterpart of the Drosophila Gap1 gene. Expression of Gap1m was relatively high in brain, placenta, and kidney tissues, and it was expressed at low levels in other tissues. A recombinant protein consisting of glutathione-S-transferase and the GAP-related domain of Gap1m stimulated GTPase of normal Ras but not that of Ras having valine at the 12th residue. Expression of the same region in Saccharomyces cerevisiae suppressed the ira2- phenotype. In addition to the GAP catalytic domain, Gap1m has two domains with sequence closely related to those of the phospholipid-binding domain of synaptotagmin and a region with similarity to the unique domain of Btk tyrosine kinase. These results clearly show that Gap1m is a novel Ras GAP molecule of mammalian cells.

Activation of Ras and formation of GAP complex during TPA-induced monocytic differentiation of HL-60 cells

In this study, it was shown that the proportion of guanosine triphosphate (GTP)-bound active Ras increased in TPA (12-o-tetradecanoyl phorbol-13-acetate)-induced monocytic differentiation of HL-60 cells. The increase of active Ras was observed at 24 hours after TPA stimulation and attained to threefold (15%) over the proportion in nontreated HL-60 cells. Herbimycin A, an inhibitor of tyrosine kinase, prevented the activation of Ras, as well as the induction of monocytic differentiation. In parallel with the activation of Ras, the proteins with molecular weights of 52, 56, 62, and 190 kD were tyrosine-phosphorylated and formed a complex with GTPase-activating protein (GAP) for Ras. In addition to the 116-kD GAP (type I GAP), the 100-kD GAP (type II GAP) molecule was markedly induced at 24 hours after TPA stimulation of HL-60 cells. These phenomena sustained for a further 24 hours during monocytic differentiation. However, they were not observed during retinoic acid-induced granulocytic differentiation of the cells. The HL-60 transfectants, which expressed a dominant inhibitory Ha-ras Asn17, showed a low level of tyrosine-phosphorylated GAP-associated proteins and did not undergo full differentiation in response to TPA. Taken together, these data indicate that the activation of Ras and GAP complex formation mutually correlate and function downstream of protein-tyrosine kinases in the signaling pathway for monocytic differentiation of HL-60 cells.

CRK protein binds to two guanine nucleotide-releasing proteins for the Ras family and modulates nerve growth factor-induced activation of Ras in PC12 cells

It has been reported that growth factors activate Ras through a complex of an adaptor type SH2-containing molecule, Grb2, and a Ras guanine nucleotide-releasing protein (GNRP), mSos. We report on the involvement of another adaptor molecule, CRK, in the activation of Ras. Overexpression of wild-type CRK proteins CRK-I and CRK-II enhanced the nerve growth factor (NGF)-induced activation of Ras in PC12 cells, although the basal level of GTP-bound active Ras was not altered. In contrast, mutants with a single amino acid substitution in either the SH2 or SH3 domain of the CRK-I protein inhibited the NGF-induced activation of Ras. Two GNRPs for the Ras family, mSos and C3G, were coimmunoprecipitated with the endogenous Crk proteins in PC12 cells. The association between C3G and the CRK mutants was dependent upon the presence of intact SH3. The SH2 domain of CRK bound to the SHC protein phosphorylated on tyrosine residues by NGF stimulation. The results demonstrate that, in addition to Grb2, CRK participates in signaling from the NGF receptor and that two GNRPs appear to transmit signals from these adaptor molecules to Ras.

Comparison of asymptomatic and symptomatic childhood glomerulonephritis progressing to renal failure: a report of Kyushu Pediatric Nephrology Study Group

We evaluated the clinicopathological features and the outcome of 33 children with primary glomerulonephritis (GN) as the cause of renal failure; 17 had asymptomatic (ASP) haematuria and/or proteinuria and the remaining 16 had symptoms suggestive of GN. The renal histology in the ASP group indicated IgA GN in 6 children, focal segmental glomerular sclerosis (FSGS) in 4, diffuse proliferative GN (DPGN) in 3, membranous GN (MGN) in 1, membranoproliferative GN (MPGN) in 1 and diffuse sclerosing GN in 2. In the symptomatic (SYP) group, FSGS was evident in 9 children, DPGN in 3, MGN in 2, IgA GN in 1 and MPGN in 1. There was no difference in the histological severity between the two groups. Fourteen children in the SYP group had nephrotic syndrome (NS) and/or hypertension at their initial visits. Only 4 children in the ASP group showed NS or hypertension during the period of follow-up. Eleven children in the ASP group and all in the SYP group were treated with immunosuppressive and/or antihypertensive drugs, but these did not improve the prognosis of the ASP children compared with those in the SYP group. There was no significant difference in the mean duration between the onset of the disease and the start of dialysis in these two groups. In conclusion, it is questionable whether the urinary mass screening programme in Japan will alter the outcome of children with GN.

Neurite outgrowth of PC12 cells is suppressed by wortmannin, a specific inhibitor of phosphatidylinositol 3-kinase

The effects of wortmannin (WT), an inhibitor of phosphatidylinositol (PI) 3-kinase, on differentiation of PC12 cells were analyzed. WT inhibited PI 3-kinase activity of PC12 cells at a concentration of 10(-7) M in vivo and in vitro. Transient inhibition of PI 3-kinase activity at the time of nerve growth factor stimulation had no effect on activation of the ras protein or neurite formation by the cells. However, continuous inhibition of PI 3-kinase blocked differentiation at the step just before neurite formation. When WT was applied to cells growing neurites, elongation of the neurites was stopped at that step. These results suggest that PI 3-kinase may be involved in neurite elongation.

Ligand-binding properties and N-glycosylation of alpha 1 subunit of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate(AMPA)-selective glutamate receptor channel expressed in a baculovirus system

The alpha 1 subunit of the mouse alpha-amino-3-hydroxy-5-methyl-4-isoxazole- propionate(AMPA)-selective glutamate receptor channel has been expressed in insect Spodoptera frugiperda cells using a baculovirus system. The recombinant receptor proteins were identified by immunocytochemical detection, Western-blot analysis, and [35S]methionine/[35S]cysteine metabolic labeling experiments. The effect of tunicamycin on the metabolic labeling and immunoblots suggested that the two products, a major protein species of approximately 104 kDa and a minor species of approximately 100 kDa, correspond to glycosylated and non-N-glycosylated forms, respectively, which was also supported by the enzymic deglycosylation experiments. The lack of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate-binding activity of non-N-glycosylated glutamate receptor expressed in the presence of tunicamycin suggested that N-glycosylation is required, directly or indirectly, for functional expression in insect cells for ligand binding. Scatchard analysis of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate binding showed a single binding site with Kd 30 nM and a Bmax value of 2.6 x 10(5) binding sites/cell or 1.5 pmol/mg protein in the total particulate fraction. Among the compounds tested in the competition studies, beta-(3,5-dioxo-1,2,4-oxadiazolidin-2-yl)-L-alanine (quisqualate) was the most potent inhibitor of the 3H-labeled alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate binding (IC50 = 30 nM), followed in decreasing order by alpha-amino-3-hydroxy-5- methyl-4-isoxazole propionate, L-glutamate, 6,7-dinitroquinoxaline-2,3-dione, 6-cyano-7-nitroquinoxaline-2,3-dione, and 2-carboxy-4-(1-methylethenyl)-3-pyrrolidineacetate (kainate). Thus, in this study we present detailed analysis of alpha-amino-3-hydroxy-5-methyl-4- isoxazole-propionate-binding activity of the homomeric (single subunit) glutamate receptor channel of mouse alpha 1 subunit and discuss possible roles of N-glycosylation of the glutamate receptor channel alpha 1 subunit.

Characterization of recombinant Xenopus MAP kinase kinases mutated at potential phosphorylation sites

Xenopus mitogen-activated protein kinase kinase (MAPKK) previously inactivated with protein phosphatase 2A can be reactivated by serine phosphorylation catalyzed by a partially purified MAPKK kinase (MAPKK-K), and is phosphorylated by MAPK on a threonine residue. The sequence analysis of a threonine-phosphorylated tryptic peptide of Xenopus MAPKK from mature oocytes suggested that Thr388 is phosphorylated in vivo. A mutant MAPKK that has Thr388 changed to Ala (T388A-MAPKK) was not phosphorylated by purified MAPK, indicating that Thr388 is phosphorylated by MAPK. We then produced and analysed MAPKKs mutated at potential serine phosphorylation sites (S218A-MAPKK and S222A-MAPKK). The wild-type MAPKK (WT-MAPKKK), T388A-MAPKK and a kinase-deficient (K97S)-MAPKK were phosphorylated efficiently by MAPKK-Ks purified from Xenopus eggs, and WT-MAPKK and T388A-MAPKK became activated. In contrast, neither S218A-MAPKK nor S222A-MAPKK was phosphorylated and activated efficiently by the Xenopus MAPKK-Ks. Similarly, WT-MAPKK, but not S218A-MAPKK or S222A-MAPKK, was activated efficiently by an active Raf-1 immunoprecipitate. However, when the recombinant STE11, a putative MAPKK-K in S. cerevisiae, was used as a source of MAPKK-K, S218A-MAPKK as well as WT-MAPKK, but not S222A-MAPKK, was phosphorylated and activated. Furthermore, replacement of Ser222 with an acidic residue (S222E) elevated substantially the basal kinase activity of MAPKK, while replacement of Ser218 (S218E) did not. These results may suggest an essential role for Ser222 phosphorylation in activating Xenopus MAPKK.

Characterization of subspecies of apolipoprotein A-I-containing lipoprotein in homozygotes for familial lecithin:cholesterol acyltransferase deficiency

We characterized the two species of lipoproteins containing apolipoprotein A-I (apoA-I), one containing only apoA-I (LpA-I) and the other containing apoA-I and apoA-II (LpA-I/A-II), in four homozygotes for familial lecithin: cholesterol acyltransferase (LCAT) deficiency. Two homozygotes lacked both LCAT mass and activity, whereas the other two had some residual LCAT mass and activity. In these patients, the amount of all apoA-I-containing lipoproteins was one fourth that of normal control subjects, and > 60% was LpA-I. The chemical composition of both LpA-I and LpA-I/A-II is characterized by markedly decreased ratios of neutral to polar lipids compared with those of normals and the sizes of LpA-I and LpA-I/A-II particles are shifted to smaller and larger diameter ranges when compared with those of normal particles. Changes in particle diameter are also reflected in slower electrophoretic mobilities of both LpA-I and LpA-I/A-II particles. All of these abnormalities were more evident in the two homozygotes who lacked LCAT activity. Incubation of LCAT-deficient plasma with LCAT markedly corrected the chemical and physical abnormalities in both LpA-I and LpA-I/A-II particles. These data, taken together, emphasize the importance of LCAT in modifying the chemical composition, size, and shape of LpA-I and LpA-I/A-II particles.

[Maternal working status and low birthweight: findings from a cohort study]

To explore possible associations of maternal working status with birthweight, a cohort study was conducted from July, 1989 to June, 1991 in 8 general hospitals in the Tokai district. Using a self-administered questionnaire, data on job employment were collected mostly in the first or second trimester. Information on delivery outcome was recorded by doctors, midwives or nurses after child birth. Included in this analysis were 1,360 pregnants who delivered a live singleton without major malformations at gestation of 37 weeks or more. The following major findings emerged. (1) No significant difference in mean birthweight was detected between working and non-working pregnants. (2) Working pregnants were at greater risk of delivering a low birthweight (< 2,500g) baby. (3) Delivery of a low birthweight baby was more frequent in multiparous than nulliparous mothers. (4) The risks of delivering a low birthweight baby significantly differed according to the maternal working status. (5) These results suggest that not only the maternal working factor itself but the working status should be deliberately taken into consideration in order to provide proper prenatal care.

Current status and perspectives of research on radiation hormesis in Japan

The CRIEPI initiated the Radiation Hormesis Research based on the following rationale. If the Luckey's claim was true, our daily activities in the radiation management would be extremely erroneous. If the Luckey's claim was false, the concept publicated would bring us serious disturbance on the radiation management in Japan. We organized a hormesis research steering committee by the specialists in the concerned field, and started researches under cooperation with many universities, National Cancer Center Research Institute, and National Institute of Radiological Sciences. After interesting results obtained by various experiments on the health effects by low dose, we are now proceeding on the Round Robin tests program including fifteen research plans with universities all over Japan. These activities are categorized as: A. Effects of free radicals produced by the low dose radiation; B. Molecular biological responses to the low dose radiation; C. Radiation effects on the neurotransmission system; D. Stimulative effects of low dose radiation on the immune systems; and E. Epidemiological studies.

Substitution of cysteine for glycine-946 in the alpha 1(I) chain of type I procollagen causes lethal osteogenesis imperfecta

Procollagen synthesized by skin fibroblasts from a patient with a lethal variant of osteogenesis imperfecta has been characterized. After pepsin digestion of the type I procollagen, a portion of the alpha 1(I) chains was recovered as a disulfide-bonded dimer. Cyanogen bromide peptide mapping suggested that a new cysteine residue was present in the alpha 1(I)CB6 fragment. Sequencing of cloned cDNAs prepared using mRNA from the proband's fibroblasts demonstrated that some of the clones contained a single base mutation that converted the glycine codon in amino acid position 946 of the alpha 1(I) chain to a cysteine codon. The thermal stability of the molecules was markedly lower than that in the case of the normal control.

A unique murine CD43 epitope Lp-3: distinct distribution from another CD43 epitope S7

In foregoing studies, we found a unique B cell differentiation antigen Lp-3 which is expressed on pre-B and premature B cells in the bone marrow, but is negative on bone marrow mature B cells and peripheral resting B cells. Nonetheless, Lp-3 was clearly positive on the majority of CD5 B(B1) cells. When we examined the biochemical nature and partial amino acid sequences of purified 132-kDa Lp-3 molecules and the nucleotide sequence of the cDNA clones, we found that Lp-3 is an epitope of CD43. Thus, the monoclonal antibody (mAb) Lp-3 may be the first mAb to murine CD43 defined by primary target structure analysis. Comparison of tissue distribution of Lp-3 and S7, an epitope previously suggested to associate with murine CD43, showed that they were similarly distributed on thymocytes, peripheral B and T cells, granulocytes, and platelets. In the bone marrow, while both Lp-3 and S7 were negative on mature B cells, the former was positive on all B lineage cells at an early ontogeny and the latter was positive only on the minor population of pre-B cells and pro-B cells. Lp-3 and S7 epitopes also showed different distributions on basement membranes of renal glomerulus, bronchus, and endometrium, lining cells of choroid plexus and muscular cells of arterioles in a variety of tissues. As CD43 has various isoforms generated by different degrees of glycosylation of the common core peptide, it is likely that Lp-3 and S7 are associated with different CD43 isoforms.

C3G, a guanine nucleotide-releasing protein expressed ubiquitously, binds to the Src homology 3 domains of CRK and GRB2/ASH proteins

CRK protein, together with GRB2/ASH and Nck proteins, belongs to the adaptor-type Src homology (SH)2-containing molecules, which transduce signals from tyrosine kinases. Here another guanine nucleotide-releasing protein (GNRP), C3G, has been identified as a CRK SH3-binding protein. The nucleotide sequence of a 4.1-kb C3G cDNA contains a 3.2-kb open reading frame encoding a 121-kDa protein, and antibodies against C3G have been shown to detect a protein of 130-140 kDa. The carboxyl terminus of C3G has a peptide sequence homologous to GNRPs for Ras, and the expression of this carboxyl terminus region suppresses the loss of CDC25 function in the yeast Saccharomyces cerevisiae. The C3G protein expressed in Escherichia coli binds to CRK and GRB2/ASH proteins. Mutational analysis of C3G assigns the SH3 binding region to a 50-amino acid region containing a proline-rich sequence. The mRNAs of both the C3G and CRK proteins are expressed ubiquitously in human adult and fetal tissues. The results of these studies suggest that the complex of CRK and C3G, or GRB2/ASH and C3G, may transduce the signals from tyrosine kinases to Ras in a number of different tissues.