Purification and primary structure of a myotoxic lysine-49 phospholipase A2 with low lipolytic activity from Trimeresurus gramineus venom

Four acidic phospholipase A2 (PLA2) isozymes named PLA2-I, II, III and IV have previously been isolated from Trimeresurus gramineus (green habu snake) venom and sequenced [Oda et al. (1991) Toxicon 29, 157; Fukagawa et al. (1992) Toxicon 30, 1131; Fukagawa et al. (1993) Toxicon 31, 957]. They contain aspartate-49 which is known to bind Ca2+, essential for catalysis. In the present study, a basic PLA2 named PLA2-V containing lysine-49 was newly isolated from the same snake venom. Its isoelectric point was 9.4 and considerably higher than those (c. 4.5) of PLA2-I-IV. PLA2-V was 1.1% as active as PLA2-I toward egg-yolk emulsion but exhibited strong myotoxicity. The amino acid sequence of PLA2-V was determined by sequencing the S-carboxamidomethylated derivative and its peptide fragments produced by enzymatic (clostripain, chymotrypsin, Achromobacter protease I and Staphylococcus aureus V8 protease) cleavages. PLA2-V consists of 122 amino acid residues and is highly homologous (72-78%) to Lys-49 PLA2s so far isolated from Viperidae snake venoms but less homologous (52%) to PLA2-I. The presence of Asn-28, which is characteristic of Lys-49 PLA2s, was confirmed.

Distribution of lectin binding in the testes of the musk shrew, Suncus murinus

Distribution of lectin binding in the testis of the musk shrew, Suncus murinus, was investigated by light and transmission electron microscopy. Not only spermatogenic cells but also Sertoli cells bound some lectins. Canavalia ensiformis agglutinin (Con A) and wheat germ agglutinin (WGA, Triticum vulgaris), indicating the presence of D-mannose and N-acetyl-D-glucosamine respectively, showed an intense reaction in the acrosomal region of early to late spermatids. Ricinus communis agglutinin I (RCA-I), peanut agglutinin (PNA, Arachis hypogaea), Bauhinia purpurea agglutinin (BPA), soybean agglutinin (SBA, Glycine max), revealing the presence of D-galactose and/or N-acetyl-D-galactosamine, bound to the acrosomal region from Golgi to acrosome-phase spermatids and abruptly decreased in intensity in maturation-phase spermatids. GS-II, indicating the presence of N-acetyl-D-glucosamine, gave an intense reaction only in the acrosome of acrosome-phase spermatids. These findings demonstrate that the appearance/disappearance of some glycoconjugates in the spermatid acrosome occurs in the musk shrew during acrosomal formation. Additionally, RCA-I, PNA and BPA revealed a strong reaction in the cytoplasm of Sertoli cells. The reaction that was observed in the intramembranous region of Sertoli cell cytoplasm at the electron microscope level appeared from stages VIII to XIII but not from stages I to VII. This finding suggests that glycoconjugates containing D-galactose may change stage-dependently in the musk shrew Sertoli cell.

Effects of calcium channel antagonists on the induction of nitric oxide synthase in cultured cells by immunostimulants

We investigated whether calcium channel antagonists would alter the induction of nitric oxide (NO) synthesis by bacterial lipopolysaccharide (LPS) alone or in combination with interferon-gamma (IFN gamma) in cultured J774 macrophages, rat vascular smooth muscle cells, rat renal mesangial cells, and rat cardiac myocytes. The induction of NO synthesis was determined by measuring nitrite, the stable end-product. The dihydropyridine calcium channel antagonists, nifedipine, manidipine, nitrendipine, benidipine, barnidipine, perdipine, and nilvadipine all reduced the LPS-induced nitrite production in a dose-dependent manner, each with a differing half-maximal inhibitory concentration, in cultured J774 macrophages. Nifedipine also inhibited nitrite production in vascular smooth muscle cells, mesangial cells, and cardiac myocytes. The half-maximal inhibitory concentrations of nifedipine were ranked as follows: smooth muscle cells < mesangial cells < cardiac myocytes. Diltiazem, at nontoxic concentrations, had no effect on the nitrite formation in the three cell types. Verapamil markedly increased the formation of nitrite in cardiac myocytes in response to LPS and IFN gamma, but not in vascular smooth muscle or mesangial cells. Exposure of cardiac myocytes to LPS and IFN gamma caused the expression of NO synthase mRNA that was significantly increased by verapamil. Thus, certain calcium channel antagonists modulate NO synthesis by altering the induction of NO synthase.

[The problems of the young tuberculosis patients in the community tuberculosis control]

In Japan the incidence of tuberculosis has decreased, but recently the decreasing speed is slowed down. In young people, the phenomenon is remarkable in the incidence for those aged 15-30 years. It will be useful to improve examinations of tuberculosis contacts, in order to prevent spread of tuberculosis infection among young people. This may also help effectively to identify high-risk groups for tuberculosis. Aichi Prefecture has a unique programme that the prefectural government can monitor and support the measures taken by the public health centers, such as examination of tuberculosis contacts. During last three years from 1991 through 1993, 333 tuberculosis cases were reported through this system. Of them 143 cases that were younger than 30 years have been analyzed; 65 cases were males and 78 were females. Those aged 20-29 years occupied 58% of the cases. More than half of the cases were diagnosed by visiting doctors. High school and college students occupied 38% of the cases, and nurses, public health nurses, and nursery school teachers occupied 20%. Cases whose source of infection was known occupied less than 30%, but more than half of them had the sources of infection in their families. This programme is very useful for prefectural government to get the information how the public health centers implement their measures against tuberculosis and to control them.

Vesnarinone inhibits induction of nitric oxide synthase in J774 macrophages and rat cardiac myocytes in culture

OBJECTIVE

We investigated whether vesnarinone alters the induction of nitric oxide (NO) synthesis by bacterial lipopolysaccharide (LPS) or in combination with interferon-gamma in cultured J774 macrophages and rat cardiac myocytes.

METHODS

The induction of NO synthesis was determined by measuring the stable end-product nitrite. The cytotoxic effect of vesnarinone was assessed by measuring cell respiration. Any change in mRNA levels for NO synthase (NOS) was determined by RT-PCR.

RESULTS

Stimulation by LPS or in combination with interferon-gamma increased the accumulation of nitrite in the supernatant of J774 macrophages or cardiac myocytes. NOS induction accounted for this accumulation of nitrite, as dexamethasone, NG-methyl-L-arginine, and cycloheximide each reduced the production of nitrite in both types of cells. Vesnarinone produced a significant decline in the cumulative production of nitrite in both types of cells without evidence of cytotoxicity. However, the addition of vesnarinone after induction of NOS did not inhibit nitrite production. Treatment with LPS or in combination with interferon-gamma led to a significant expression of NOS mRNA in both types of cells that was significantly reduced by vesnarinone.

CONCLUSIONS

Vesnarinone inhibited NO synthesis by inhibiting the induction of NOS in J774 macrophages and cardiac myocytes. This drug may exert a beneficial effect in patients with heart failure, in part, by attenuating the production of NO.

Induction of neurite outgrowth by MAP kinase in PC12 cells

Treatment of PC12 cells with nerve growth factor (NGF) results in neural differentiation of the cells, inducing neurite outgrowth. Ras protein has been shown to play an essential role in this process. To examine whether or not the MAP kinase (MAPK) cascade mediates the NGF- and Ras-induced neural differentiation process, we injected PC12 cells with constitutive active forms of each components of the MAPK cascade. When a moderately active mutant of Xenopus MAPK kinase (S222E-MAPKK) in which Ser 222 was changed into glutamic acid was injected, the neurite outgrowth of PC12 cells occurred to some extent. Injection of an N-terminal truncated STE11 protein (delta N-STE11), a constitutively active form of STE11 which is a yeast MAPKK kinase, induced neurite outgrowth in PC12 cells. Furthermore, injection of thiophosphorylated MAPK, but not purified active MAPK, into PC12 cells resulted in neurite outgrowth. Thiophosphorylated MAPK was resistant to protein phosphatase 2A treatment, while purified active MAPK was inactivated by this treatment. All these results have suggested that sustained activation of MAPK is sufficient for PC12 cell differentiation. In accord with this, the delta N-STE11- or S222E- MAPKK-induced neurite outgrowth was inhibited by coinjection of CL-100 protein, a dual-specificity phosphatase that is capable of inactivating MAPK.

A low protein diet increases 4-nitrophenol-UDPglucuronosyltransferase but decreases chloramphenicol-UDPglucuronosyltransferase activity and mRNA level in livers of rats treated with polychorinated biphenyls

We have examined the effects of dietary level of protein (5% or 30% in casein) on enzyme activities and mRNA levels of two xenobiotic-inducible UDPglucuronosyltransferase (UDPGT) enzymes, such as chloramphenicol-UDPGT (CP-UDPGT) and 4-nitrophenol-UDPGT (4NP-UDPGT), in the livers of rats treated or not treated with polychlorinated biphenyls (PCB). In animals fed 5% casein and not treated with PCB, CP-UDPGT activity tended to be lower than in rats fed 30% casein. In contrast, 4NP-UDPGT activity was higher in rats fed 5% casein. In rats treated with PCB, the activities of both enzymes were increased. CP-UDPGT mRNA level was higher (1.4-fold) in rats fed 30% dietary casein than in those fed 5% casein. In contrast, 4NP-UDPGT mRNA level was higher (2.8-fold) in rats fed 5% casein than in those fed 30% casein. These changes in mRNA levels paralleled those in the activities of the two enzymes. The data indicate that the dietary protein is an important factor controlling the expression of hepatic xenobiotic-inducible UDPGT genes and modulates the capacity of the liver to metabolize foreign compounds.

Functional CD4+ T cell subsets defined by expression of CD45RC and NTA260 antigens and age-associated polarization in murine lupus

Using two mAb, one specific to the alternative exon 6-dependent epitope of CD45 molecules (JH6.2) and one a natural thymocytotoxic autoantibody (NTA) with an unknown reactive epitope (NTA260), we subdivided splenic CD4+ T cells from 2-month-old BALB/c mice into five phenotypically distinct subsets. CD45RC+NTA260- (S I) cells were phenotypically analogous to CD4+ T cells predominating in newborn mice and produced a significant amount of IL-2, but not so IL-4, IL-10 or IFN-gamma when stimulated with immobilized anti-CD3 mAb in vitro. They appeared to consist mainly of naive ThP cells. The CD45RC+NTA260+ (S II) subset also produced IL-2, but not other cytokines; however, the IL-2 levels produced were much higher than seen with the S I subset, thereby suggesting the predominance of further maturated ThP cells. The CD45RC-NTA260+ (S III) subset mainly produced IL-4, IL-10, IFN-gamma and less IL-2, and contained memory cells that helped the secondary antibody response to a recall antigen, and hence contained Th2 and probably a mixture of Th0 and Th1 cells. The CD45RC-NTA260- (S IV) subset was a poor responder to the immobilized anti-CD3 mAb. The CD45RCbrightNTA260dull (S V) subset consisted of a small number of cells that were phenotypically analogous to activated CD4+ T cells. While an age-associated decrease in the proportion of S I and less markedly in S II and in turn increase in S III subsets of CD4+ T cells occurred in normal BALB/c mice, autoimmune disease-prone (NZB x NZW)F1 mice showed a marked age-associated decrease in the proportion of not only S I, II but also III subsets. As aged (NZB x NZW)F1 mice carry CD4+ T helper cells for IgG anti-DNA antibody production, such age-associated polarization to the S IV subset appears to be critical in the pathogenesis of autoimmune disease in these mice.

Morphology of ras-transformed cells becomes apparently normal again with tyrosine kinase inhibitors without a decrease in the ras-GTP complex

Radicicol, an inhibitor of protein-tyrosine kinase, was found to cause morphological reversion of v-Ha-ras-transformed NIH3T3 fibroblasts and T24 human urinary bladder carcinoma cells that contain an activated ras mutation. The network of actin stress fibers was restored during the treatment with radicicol. A similar morphological change was observed with another protein-tyrosine kinase inhibitor, herbimycin A. Radicicol did not cause any changes in the proportion of the active GTP binding form of p21ras or its subcellular localization. These results rule out the possibility that the morphological reversion by radicicol is due to direct or indirect inhibition of the p21ras function. Cycloheximide and actinomycin D inhibited the morphological change by radicicol, suggesting that the induced transcription of a gene(s) followed by de novo protein synthesis is required for suppression of the transformed phenotype in ras-transformed cells by tyrosine kinase inhibitors.

Accelerated evolution in the protein-coding regions is universal in crotalinae snake venom gland phospholipase A2 isozyme genes

The nucleotide sequences of four genes encoding Trimeresurus gramineus (green habu snake, crotalinae) venom gland phospholipase A2 (PLA2; phosphatidylcholine 2-acylhydrolase, EC 3.1.1.4) isozymes were compared internally and externally with those of six genes encoding Trimeresurus flavoviridis (habu snake, crotalinae) venom gland PLA2 isozymes. The numbers of nucleotide substitutions per site (KN) for the noncoding regions including introns were one-third to one-eighth of the numbers of nucleotide substitutions per synonymous site (KS) for the protein-coding regions of exons, indicating that the noncoding regions are much more conserved than the protein-coding regions. The KN values for the introns were found to be nearly equivalent to those of introns of T. gramineus and T. flavoviridis TATA box-binding protein genes, which are assumed to be a general (nonvenomous) gene. Thus, it is evident that the introns of venom gland PLA2 isozyme genes have evolved at a similar rate to those of nonvenomous genes. The numbers of nucleotide substitutions per nonsynonymous site (KA) were close to or larger than the KS values for the protein-coding regions in venom gland PLA2 isozyme genes. All of the data combined reveal that Darwinian-type accelerated evolution has universally occurred only in the protein-coding regions of crotalinae snake venom PLA2 isozyme genes.

[The relation between delivery method and prognosis for very low birth weight infants]

To further understand the relationship between perinatal factors and prognosis (neonatal and infantile death and major handicaps), we retrospectively studied 128 singletons weighing less than 1,500g (very low birth weight; VLBW) infants, without maternal complications, IUGR or major congenital anomalies. The gestational age (mean +/- SD) at delivery and the birth weight (mean +/- SD) of subjects were 27.1 +/- 2.0 weeks and 1,041.1 +/- 264.1g, respectively. The results of the current study were as follows: 1) Malpresentation, low Apgar score (APS) and Respiratory distress syndrome (RDS) were observed more frequently in non-intact survivors than in intact survivors with statistical significance. Although the occurrence of fetal distress was correlated with low pH in the umbilical artery, no significant correlation was evident between the prognosis and either of the two above mentioned factors. The intact survivors had a significantly high frequency of PROM despite no correlation with signs of infection (WBC, CRP). 2) As to delivery methods in terms of prognosis, a cephalic-vaginal group had the best prognosis and a breech-vaginal group had the worst, with statistical significance. A higher frequency of poor prognosis for infants was found in a malpresentation group with cesarean delivery and cervical dilation of more than 4cm. Thus, vaginal delivery is a possible option in case of cephalic VLBW infants.

Expression and characterization of the zeta 1 subunit of the N-methyl-D-aspartate (NMDA) receptor channel in a baculovirus system

Using a baculovirus expression vector system, the zeta 1 subunit of the mouse N-methyl-D-aspartate (NMDA) receptor channel was expressed in Spodoptera frugiperda insect cells. The peptide corresponding to the C-terminus of the zeta 1 subunit was synthesized by using the multiple antigen peptide (MAP) system, and an antibody to the synthetic peptide was produced. Immunoblotting using the newly developed antibody revealed the major 122-kDa and the minor 104-kDa protein bands. The effect of tunicamycin on the immunoblots and [35S]methionine/[35S]cysteine metabolic radiolabeling suggested that the two bands corresponded to glycosylated and non-N-glycosylated forms, respectively. Membranes prepared from insect cells infected with the recombinant virus had the binding activity of antagonist ligand 5,7-[3-3H]dichlorokynurenate (DCKA) of a glycine recognition domain of the receptor. Both immunofluorescence labeling and the [3H]DCKA binding assays also showed a greater level of expression (Bmax = 51 pmol/mg protein) in the insect cells. The ligand binding characteristics of the receptors expressed in insect cells suggested that the single zeta 1 subunit protein has glycine antagonist binding properties comparable to those of the native NMDA receptor channels. The lack of DCKA-binding activity of the non-N-glycosylated NMDA receptor expressed in the presence of tunicamycin suggested that N-linked oligosaccharide is essentially required for expression of a functional receptor in insect cells. This is the first report describing the importance of N-glycosylation for the acquisition of ligand binding to NMDA receptor channel subunit protein.

A constitutive effector region on the C-terminal side of switch I of the Ras protein

The "switch I" region (Asp30-Asp38) of the Ras protein takes remarkably different conformations between the GDP- and GTP-bound forms and coincides with the so-called "effector region." As for a region on the C-terminal side of switch I, the V45E and G48C mutants of Ras failed to promote neurite outgrowth of PC12 cells (Fujita-Yoshigaki, J., Shirouzu, M., Koide, H., Nishimura, S., and Yokoyama, S. (1991) FEBS Lett. 294, 187-190). In the present study, we performed alanine-scanning mutagenesis within the region Lys42-Ile55 of Ras and found that the K42A, I46A, G48A, E49A, and L53A mutations significantly reduced the neurite-inducing activity. This is an effector region by definition, but its conformation is known to be unaffected by GDP-->GTP exchange. So, this region is referred to as a "constitutive" effector (Ec) region, distinguished from switch I, a "switch" effector (Es) region. The Ec region mutants exhibiting no neurite-inducing activity were found to be correlatably unable to activate mitogen-activated protein (MAP) kinase in PC12 cells. Therefore, the Ec region is essential for the MAP kinase activation in PC12 cells, whereas mutations in this region only negligibly affect the binding of Ras to Raf-1 (Shirouzu, M., Koide, H., Fujita-Yoshigaki, J., Oshio, H., Toyama, Y., Yamasaki, K., Fuhrman, S. A., Villafranca, E., Kaziro, Y., and Yokoyama, S. (1994) Oncogene 9, 2153-2157).

N-linked glycosylation of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA)-selective glutamate receptor channel alpha 2 subunit is essential for the acquisition of ligand-binding activity

The N-linked glycosylation of the alpha 2 subunit of the mouse alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA)-selective glutamate receptor (GluR) channel was characterized. The receptor subunit protein has five putative N-glycosylation sites. The recombinant receptor proteins were identified by [35S]methionine/[35S]cysteine metabolic labeling, western blot analysis, immunocytochemical detection, and [3H]AMPA binding experiments when expressed in insect Spodoptera frugiperda cells using a baculovirus system. The effect of tunicamycin on the metabolic labeling and immunoblots suggested that the two products, a major protein species of approximately 102 kDa and a minor species of approximately 98 kDa, correspond to glycosylated and unglycosylated forms, respectively, which was also supported by the enzymic deglycosylation experiments. Immunofluorescence staining of tunicamycin-treated cells expressing only the unglycosylated form differed little from that of tunicamycin-nontreated cells expressing both glycosylated and unglycosylated forms. The lack of AMPA-binding activity of the unglycosylated form expressed in the presence of tunicamycin suggested that N-glycosylation is required, directly or indirectly, for functional expression in insect cells for ligand binding. These results demonstrate that occupancy of at least one N-glycosylation site is required for the formation and maintenance of the GluR alpha 2 subunit protein in an active conformation for ligand binding. Possible roles of N-glycosylation of GluR alpha 2 subunit protein are discussed.

The effect of pentoxifylline on acid-induced alveolar epithelial injury

BACKGROUND

Acid instillation into one lung is known to cause an increase in the permeability of the endothelium to protein in both the instilled and the contralateral lungs. Activated neutrophils are believed to be involved in causing this increased permeability. Pentoxifylline, a drug used in clinical practice, has multiple effects on neutrophils, including inhibition of phagocytosis, degranulation, and superoxide generation. This study investigated whether pretreatment with pentoxifylline would protect the alveolar epithelium or lung endothelium from injury.

METHODS

The effect of acid instillation into one lung of anesthetized rabbits using several quantitative parameters was investigated. The quantification of the bidirectional movement of the alveolar (125I-albumin) and the circulating protein tracers (131I-albumin) was used as a measurement of the permeabilities of the lung epithelium and the lung endothelium in the acid-instilled lung. Bronchoalveolar lavage and measurement of the entry of the circulating protein tracer were used to assess the permeabilities of these barriers in the noninstilled lung.

RESULTS

The instillation of HCl (pH 1.25, 1.2 ml/kg) into the right lung resulted in an increase in the protein permeability of the right lung's alveolar epithelium and endothelium as well as an increase in the permeability to protein of the left lung's endothelium. Pentoxifylline pretreatment attenuated the increase in the endothelial permeability of both lungs by 50% and restored the PaO2/FIO2 to normal in the pretreated animals exposed to acid injury.

CONCLUSIONS

Acid aspiration causes a dramatic increase in the alveolar epithelial permeability of the acid-instilled lung, but the permeability of the alveolar epithelium of the contralateral lung remains normal. In contrast, unilateral acid instillation causes an increase in the permeability of the endothelium of both lungs. The increase in endothelial permeability can be attenuated by pretreatment with pentoxifylline administration, and this leads to restoration of normal gas exchange.

Structures of genes encoding TATA box-binding proteins from Trimeresurus gramineus and T. flavoviridis snakes

A cDNA encoding the Trimeresurus gramineus (Tg; green habu snake) TATA-box-binding protein (TgTBP) was cloned and sequenced. The cDNA encodes a 33-kDa protein with an extensive sequence similarity to those derived from other organisms, except for the N-terminal domain. Genes encoding TgTBP and Trimeresurus flavoviridis (Tf; habu snake) TBP (TfTBP) were isolated using a TgTBP cDNA and their nt sequences were determined. They are the first TBP genes entirely sequenced in higher animals. Both genes span over 15 kb and are constructed from eight exons and seven introns. Comparison of the loci of introns on the aligned amino-acid sequences of TBP from six organisms (Tg, Tf, mouse, Arabidopsis thaliana, Schizosaccharomyces pombe and Acanthamoeba castellanii) indicated that there are three highly conserved loci in the C-terminal domain.

[The synergistic effect of interferon-gamma on the induction of nitric oxide synthase by lipopolysaccharide in vascular smooth muscle]

Bacterial lipopolysaccharide (LPS) and other immunostimulants induce an isoform of nitric oxide synthase (iNOS) in vascular smooth muscle (VSM) which produces large quantities of nitric oxide (NO) and profound vasodilation. This process has been implicated as the cause of gram-negative septic shock. It has been demonstrated that interferon-gamma (IFN) markedly potentiates cytokine-induced NO synthesis in various cell types. However, little is known about the mechanism of this enhancing effect of IFN. The present study was undertaken to investigate the effect of IFN on LPS-induced NO synthesis and iNOS mRNA expression in VSM and the possibility of nuclear factor kB (NFkB) involvement in the effect of IFN. LPS-induced NO synthesis is markedly potentiated by IFN in VSM. Expression of iNOS mRNA in VSM costimulated with IFN and LPS was greatly increased compared to that induced by LPS alone. IFN did not alter the lifetime of iNOS mRNA. LPS stimulated translocation into the nuclei of NFkB which is believed to play an important role in the induction of iNOS, but IFN did not enhance NFkB activation by LPS. These results suggest that the enhancing effect of IFN is due to the increased transcription of the iNOS gene rather than a decreased degradation of iNOS mRNA and that the NFkB activation pathway is not involved in this effect of IFN.

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.

Protein H--a surface protein of Streptococcus pyogenes with separate binding sites for IgG and albumin

Protein H, a molecule expressed at the surface of some strains of Streptococcus pyogenes, has affinity for the constant (IgGFc) region of immunoglobulin (Ig) G. In absorption experiments with human plasma, protein H-sepharose could absorb not only IgG but also albumin from plasma. The affinity constant for the reaction between albumin and protein H was 7.8 x 10(9) M-1, which is higher than the affinity between IgG and protein H (Ka = 1.6 x 10(9) M-1). Fragments of protein H were generated with deletion plasmids and polymerase chain reaction (PCR) technology. Using these fragments in various protein-protein interaction assays, the binding of albumin was mapped to three repeats (C1-C3) in the C-terminal half of protein H. On the albumin molecule, the binding site for protein H was found to overlap the site for protein G, another albumin- and IgGFc-binding bacterial surface protein. Also IgGFc-binding could be mapped with the protein H fragments and the region was found N-terminally of the C repeats. A synthetic peptide (25 amino acid residues long) based on a sequence in this region was shown to inhibit the binding of protein H to immobilized IgG or IgGFc. This sequence was not found in previously described IgGFc-binding proteins. However, two other cell surface proteins of S. pyogenes exhibited highly homologous regions. The results identify IgGFc- and albumin-binding regions of protein H and further define and emphasize the convergent evolution among bacterial surface proteins interacting with human plasma proteins.

Different interactions of Grb2/Ash molecule with the NGF and EGF receptors in rat pheochromocytoma PC12 cells

We have previously shown that nerve growth factor (NGF) induces a rapid and relatively continuous activation of Ras in rat pheochromocytoma PC12 cells while epidermal growth factor (EGF) activates Ras transiently, and that tyrosine kinase activity of the NGF receptor is essential for the activation of Ras (Muroya et al., Oncogene, 7, 277-281, 1992). In order to explore the signaling mechanism from tyrosine kinase to Ras activation in more detail, interactions between two adaptor molecules, Shc and Grb2/Ash, which contain Src homology regions, and their interactions with the NGF and EGF receptors were examined. Both NGF and EGF induced rapid tyrosine phosphorylation of Shc and its association with both the receptors and with Grb2/Ash. When cells were stimulated with EGF at 4 degrees C, the activation of Ras proceeded slowly and MAP kinase activation was quite low. Under such restricted conditions, tyrosine-phosphorylated Shc formed a complex with Grb2/Ash, suggesting that the complex formation may be one of the immediate early responses. In contrast to Shc, Grb2/Ash bound to EGF receptor but did not form a stable complex with the NGF receptor. These results suggest that there may be an alternative pathway for the activation of Ras in PC12 cells.

Long-term follow-up of patients with epithelial carcinoma of the ovary

OBJECTIVES

To determine the long-term outcomes of patients with epithelial ovarian cancer.

METHODS

A group of 298 patients with epithelial ovarian cancer were treated with combination chemotherapy between July 1979 and January 1986 at the Tokai Ovarian Tumor Study Group. Long-term results of these patients were analyzed.

RESULTS

Five-year survival and 10-year survival rates of all the patients were 53% and 47%, respectively. Five-year survival and 10-year survival rates for stage I were 89% and 79%, 59% and 56% for stage II, 27% and 22% for stage III, and 9% and 9% for stage IV, respectively. Survival of mucinous and endometrioid cell types were decreased after 5 or more years. In stages II-IV, cisplatin-based chemotherapy produced better results than mitomycin-C, 5-Fu, cytarabine (MFC) therapy.

CONCLUSIONS

Long-term results of epithelial ovarian cancer were not favorable even in mucinous and endometrioid cell types. For long-term results, cisplatin-based chemotherapy was effective in advanced ovarian cancer. Long-term follow-up of ovarian cancer is important and necessary.

Site-directed mutagenesis, fluorescence, and two-dimensional NMR studies on microenvironments of effector region aromatic residues of human c-Ha-Ras protein

The Tyr residues in positions 32 and 40 of human c-Ha-Ras protein were replaced by site-directed mutagenesis (Y32F, Y32W, Y40K, and Y40W) to examine their roles in the signal-transducing activity and the sensitivity to the GTPase activating protein (GAP). The signal-transducing activity of the oncogenic Ras protein in PC12 cells was lost upon mutations Y32F and Y40K, but retained upon mutations Y32W and Y40W. These results suggest that residues 32 and 40 are both required to have aromatic groups and residue 32 is further required to have a hydrogen donor. On the other hand, three mutations (Y32F, Y32W, and Y40W) caused no appreciable reduction in either GAP-binding affinity or GAP sensitivity. By the Y40K mutation, GAP-binding affinity was slightly lowered, while GAP sensitivity was drastically impaired. Therefore, for residues 32 and 40 of Ras, interactions with GAP appear to be different from those with the target of signal transduction in the PC12 cell. As for the Y32W-Ras protein bound with an unhydrolyzable GTP analogue (GMPPNP), the Trp32 fluorescence is appreciably red-shifted, weaker, and more susceptible to KI quenching as compared to that of the GDP-bound form. Two-dimensional NMR spectroscopy with selectively deuterated Ras proteins revealed fewer and weaker nuclear Overhauser effects on the aromatic protons of Trp32 in the GMPPNP-bound form than in the GDP-bound form. This indicates that the side chain of Trp32 is more exposed to the solvent in the GMPPNP-bound form than in the GDP-bound form.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidermal growth factor-receptor mutant lacking the autophosphorylation sites induces phosphorylation of Shc protein and Shc-Grb2/ASH association and retains mitogenic activity

Epidermal growth factor (EGF) receptor (EGFR) can induce cell growth and transformation in a ligand-dependent manner. To examine whether the autophosphorylation of EGFR correlates with the capacity of the activated EGFR to induce cell growth and transformation, we truncated the human EGFR just after residue 1011, removing all three major autophosphorylation sites (DEL1011). Further, a point mutation was introduced at another autophosphorylation site, Tyr-992-->Phe (DEL1011+F992). The wild-type and mutant receptors were stably expressed in a NIH 3T3 variant cell line that expresses an extremely low level of endogenous EGFR and does not grow with EGF. As expected, DEL1011 and DEL1011+F992 were found to be severely impaired in EGF-induced autophosphorylation, due to the deletion of the appropriate target tyrosines. However, mutant receptors still could induce EGF-dependent DNA synthesis, morphological transformation, and anchorage-independent growth, although the extent of these was significantly reduced when compared with wild-type EGFR. EGF-induced tyrosine phosphorylation of Ras-GTPase activating protein-associated protein p62 and phospholipase C gamma 1 was dramatically reduced in the cells expressing DEL1011 and DEL1011+F992. On the other hand, tyrosine phosphorylation of Shc, complex formation of Shc-Grb2/Ash, and activation of microtubule-associated protein kinase were still fully induced upon EGF stimulation without binding of Shc or Grb2/Ash to the mutant receptor. Thus, tyrosine phosphorylation of Shc may play a crucial role for activating Ras and generating mitotic signals by the activated EGFR mutant.

Recurrence of epithelial ovarian carcinoma after clinical remission

One hundred and eighty-eight patients with epithelial ovarian carcinoma were treated with primary cytoreductive surgery and subsequent combination chemotherapy. The first recurrent findings such as sites and disease-free interval were analyzed in 141 patients who were clinically remitted 6 months after operation or chemotherapy. Fifty-seven cases had a recurrence. Five-year disease-free survival rates were 75, 72, 29, and 0% in stage I, II, III, and IV, respectively. Twenty-one of 22 patients with > 2 cm maximum residual tumor died, although they once achieved clinical remission. Significant differences were observed between histologic types, and the disease-free survival rate was lowest for serous cystadenocarcinoma. Nine of 15 stage IV patients with serous histology experienced remission, but none of the 8 in stage IV with other histologies did so, suggesting that serous adenocarcinoma is sensitive to chemotherapy and conducive to clinical remission. However, all stage IV patients in remission encountered a recurrence. Intra-abdominal cavity and lymph node were frequently the initial recurrent sites (38 and 27%, respectively). On the other hand, the incidence of distant recurrence was as high as 27%, and 8 of 16 cases with distant recurrence were stage I. Survival time after recurrence was not different among initial sites of recurrence and mean survival time was 15 months.

Striatal dopamine turnover during treadmill running in the rat: relation to the speed of running

To evaluate the physiological action of striatal dopamine (DA) in exercise, rats were trained to run on a straight treadmill. Extracellular DA and its metabolites, dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) were measured by in vivo microdialysis, and striatal tissue tyrosine hydroxylase (TH) activity and monoamine oxidase (MAO) activity were measured using high performance liquid chromatography (HPLC) and spectrophotometer. DA turnover was increased by running, and the increase in DOPAC and HVA was closely related to the speed of running, while the increase in DA had no relationship to the speed. The threshold for the increase in DA, DOPAC, and HVA was between 300 and 660 cm/min. Striatal tissue TH activity was elevated up to 135% of basal values after the rats were trained for 7 days to run at 1800 cm/min. Just after running for 20 min, there was a further increase to 180%. These values became 150% and 90% of basal values at 2 h and 6 h, showing a similar time course as DA detected by microdialysis. MAO-B activity increased up to 160% of basal values after 7 days training but decreased to 130% and 110% just after and 2 h after running, then increased to 145% 6 h after running. MAO-A showed a similar variation as MAO-B. These data suggest that both the synthesis and metabolism of DA have a close relationship with physical exercise and might contribute to adjusting extracellular DA levels within an adequate range in response to exercise intensity.