Up-regulation of oxytocin receptors in porcine endometrium by adenosine 3',5'-monophosphate

Porcine endometrial cells (a mixture of epithelial, stromal, and glandular cells) were examined for the presence of oxytocin (OT) receptors using a cell culture system and a 125I-labeled OT antagonist. Binding specificity was tested in displacement studies with various related peptides. Scatchard analyses revealed the presence of a binding site with a dissociation constant (Kd) = 0.9 nM and a capacity of 1.9 fmol/10(5) cells. These cells, which were obtained from prepubertal gilts and thus had not been exposed to endogenous ovarian steroids, were used as a model to evaluate the possible action of ovarian steroids and intracellular cAMP on OT receptors. Although ovarian steroids showed no effect on OT receptors, forskolin (an adenylate cyclase activator) and dibutyryl cAMP caused 1.5- to 1.6-fold increases in specific binding of OT without changing the binding affinity. When the endometrial cells were exposed to OT (0.1-1000 nM) in combination with arachidonic acid (10 microM), OT stimulated prostaglandin F2 alpha secretion in a dose-dependent manner. These results indicate the presence of functional OT receptors in prepubertal porcine endometrial cells and suggest that the concentration of OT receptors may be regulated by one or more substances that raise intracellular cAMP levels.

Complete rescue of lethal albino c14CoS mice by null mutation of 4-hydroxyphenylpyruvate dioxygenase and induction of apoptosis of hepatocytes in these mice by in vivo retrieval of the tyrosine catabolic pathway

Hereditary tyrosinemia 1 (HT1) is characterized by progressive liver damage, from infancy, and by a high risk for hepatocellular carcinoma. HT1 is due to mutations in the fumarylacetoacetate hydrolase gene Fah, encoding the last enzyme in the tyrosine catabolic pathway. Lethal albino deletion c14CoS mice and mice with target-disrupted Fah are models for HT1, but they die in the perinatal period, albeit with a different phenotype from that seen in HT1 in humans. We first asked whether homozygous null mutation of the 4-hydroxyphenylpyruvate dioxygenase gene Hpd could rescue the homozygous c14CoS mice (c14CoS/c14CoS or Fah-/-). The double mutant Fah-/- Hpd-/- mice appeared normal, at least until age 18 months, and there was no evidence of liver disease, findings that facilitated examination of the effect of Fah-/- on mature and unmodified hepatocytes in vivo. The hepatocytes of Fah-/- undergo rapid apoptosis, and acute death follows. Essentially the same phenomena were observed when Fah-/- Hpd-/- mice were administered homogentisate intraperitoneally. These changes in liver pathology in Fah-/- Hpd-/- mice after the administration of homogentisate were associated with massive urinary excretion of succinylacetone. These results suggest that accumulation of fumarylacetoacetate, maleylacetoacetate, or succinylacetone seems to trigger the endogenous process of apoptosis in hepatocytes that lack fumarylacetoacetate hydrolase activity. This apoptosis may be related to the development of hepatocellular carcinomas seen in HT1 patients and pharmaceutically treated fumarylacetoacetate hydrolase-deficient mice.

Neutrophil elastase inhibitor, ONO-5046, modulates acid-induced lung and systemic injury in rabbits

BACKGROUND

Acid instillation leads to direct lung and to secondary systemic organ injury, probably via activated macrophages and neutrophils. This study investigated the effects of neutrophil elastase on organ injury after unilateral lung acid instillation by administrating a specific neutrophil elastase inhibitor, ONO-5046, before acid instillation.

METHODS

Three groups of anesthetized rabbits (n = 12 in each group) underwent tracheostomies, and instillations were made into their right lower lobe airspaces with either phosphate buffered saline (pH, 7.4; volume, 1.2 ml/kg; n = 12) or HCl (pH, 1.25; volume, 1.2 ml/kg; n = 24). In half of the acid-instilled rabbits, ONO-5046, 10 mg/kg, was given intravenously 15 min before the HCl instillation, and then 10 mg x kg(-1) x h(-1) of the drug was continuously infused throughout the experiment. The other groups of animals received the vehicle intravenously. Anesthesia and mechanical ventilation was continued for 8 h, whereas arterial blood gases were sampled intermittently. Eight hours after saline or acid instillation, the animals were killed, and their lungs, heart, kidneys, liver, and small intestines were harvested. Wet-to-dry weight ratios (W/ D) and myeloperoxidase (MPO) assays of these organs were done, and elastase assays on the bronchoalveolar lavage fluids (BALF) obtained from each lung also were performed.

RESULTS

Pretreatment with ONO-5046 attenuated the physiologic changes seen in the vehicle-treated animals. Significant decreases in W/D of the noninstilled lungs and of the small intestine and normalization of the oxygenation of the experimental animals occurred. The ONO-5046 pretreatment did not affect the neutrophil sequestration in the lungs or in the other organs as determined by neutrophil counts in BALF and by the MPO assays.

CONCLUSIONS

A neutrophil elastase inhibitor, ONO-5046, administered immediately before acid instillation attenuated the physiologic changes seen in the vehicle-treated animals. The drug blocked neutrophil elastase but did not block neutrophil sequestration in the lungs, although the drug improved measurements of lung injury.

[Activation of Rap1, antagonist to ras, by Crk-C3G]

Rap1 was identified as gene whose overexpression suppressed transformation by ras. Rap1 belongs to the Ras family. The amino acid sequences of Rap1 and Ras show 55% identity to each other. Due to this high sequence similarity, Rap1 binds to effector molecules of Ras, however, Rap1 does not activate them. Thus, Rap1 functions are antagonistic to Ras in the cells. C3G was identified as a Crk SH3-binding guanine nucleotide exchange factor. Biochemical and cell biological analyses revealed that C3G is a Rap1 activator. Since it has been considered that Crk transduces signals from tyrosine kinases, this finding suggests that the activity of Rap1 is also under the control of tyrosine kinases. Overexpression of C3G in ras-transformed cells caused the morphology of the cells to revert to that of normal cells. Moreover, a mutant cell line that was resistant to EGF-dependent transformation was isolated. In the cell line a mutation was found in crk gene that was the cause of the resistance. These findings suggest that Crk-C3G-Rap1 pathway may function as an anti-transformation machinery.

Enhancement of guanine-nucleotide exchange activity of C3G for Rap1 by the expression of Crk, CrkL, and Grb2

Crk is an adaptor protein that consists almost entirely of SH2 and SH3 domains. We have previously demonstrated, by using in vivo and in vitro systems, that C3G, which was identified as a Crk SH3 domain-binding guanine nucleotide exchange factor, specifically activates Rap1. C3G also binds to other adaptor proteins, including CrkL and Grb2. In the present study, we analyzed the effect of Crk, CrkL, and Grb2 on the C3G-Rap1 pathway. Expression of Crk, CrkL, and Grb2 with C3G in Cos1 cells significantly increased the ratio of GTP/GDP bound to Rap1. Both the SH2 and SH3 domains of Crk were required for this activity. However, Crk did not stimulate the guanine nucleotide exchange activity of C3G for Rap1 in vitro, suggesting that Crk does not activate C3G by an allosteric mechanism. The requirement of the SH2 domain of Crk for the enhancement of guanine nucleotide exchange activity for Rap1 could be compensated for by the addition of a farnesylation signal to Crk, indicating that Crk enhanced the guanine nucleotide exchange activity of C3G by membrane recruitment of C3G. These results demonstrate that Crk, CrkL, and Grb2 positively modulate the C3G-Rap1 pathway primarily by recruiting C3G to the cell membrane.

Activation of R-Ras GTPase by GTPase-activating proteins for Ras, Gap1(m), and p120GAP

The enzymatic properties of Gap1(m) were characterized using three Ras and R-Ras proteins as substrates and were compared with those of p120GAP. Gap1(m) stimulated the GTPase of Ras better than that of R-Ras, in contrast to p120GAP which promoted the GTPase of R-Ras better than that of Ras. The EC50 values of Gap1(m) for Ha-Ras and R-Ras were 0.48 +/- 0.02 and 1.13 +/- 0.12 nM, respectively, whereas the EC50 values of p120GAP for Ha-Ras and R-Ras were 23.1 +/- 1.9 and 3.86 +/- 0.38 nM, respectively. The affinities of Gap1(m) and p120GAP to the substrates determined by competitive inhibition by using Ha-Ras.GTPgammaS (guanosine 5'-O-(3-thiotriphosphate)) or R-Ras.GTPgammaS as a competitor agreed well with the substrate specificities of these GTPase-activating proteins. The Km values of Gap1(m) for Ha-Ras and R-Ras were 1.53 +/- 0.27 and 3.38 +/- 0.53 microM, respectively, which were lower than that of p120GAP for Ha-Ras (145 +/- 11 microM) by almost 2 orders of magnitude. The high affinity of Gap1(m) to the substrates and its membrane localization suggest that Gap1(m) may act as a regulator of the basal activity of Ha-Ras and R-Ras.

[Effects of loprinone hydrochloride on hemodynamics and respiratory oxygenation in patients after cardiac surgery]

Loprinone hydrochloride (Lop), a phosphodiesterase fraction III inhibitor and positive inotrope, was recently released in Japan. We evaluated its dose-related effects on hemodynamics and oxygenation as as well as on plasma levels of Lop in ten patients after cardiac surgery. Immediately after admission to the intensive care unit, baseline hemodynamics and arterial blood gas data were obtained; patients with inotropic support, were given 0.1, 0.2, 0.3 microgram.kg-1.min-1.lop over 1 hour incrementally, and additional data were obtained. CI increased significantly from baseline (2.1 +/- 0.3 l.min-1.m-2) to 3.2 +/- 0.8 at 0.3 microgram.kg-1.min-1. Systemic vascular resistance decreased significantly from baseline (2853 +/- 439 dynes.sec.cm-5.m-2) to 1554 +/- 440 at 0.3 micrograms. kg-1.min-1, and mean arterial pressure also decreased significantly from baseline. There were no significant changes in heart rate (HR), central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), or PaO2.FIO2(-1) in patients over the period evaluated. Plasma levels of Lop rapidly increased to 27.8 ng.ml-1 (effective level; 20 ng.ml-1) at 0.3 microgram.kg-1.min-1. In this study, Lop was shown to effectively increase CI in patients after cardiac surgery with no significant changes in HR, CVP, PAOP or PaO2/FIO2. Thus, Lop has a beneficial effect in the treatment of patients with low cardiac output immediately after cardiac surgery.

Induction of tetrahydrobiopterin synthesis in rat cardiac myocytes: impact on cytokine-induced NO generation

Because tetra-hydrobiopterin (BH4) is an essential cofactor for nitric oxide (NO) formation, we investigated whether BH4 synthesis is required for cytokine-induced NO production in cultured rat cardiac myocytes. The total biopterin content of untreated cardiac myocytes was below our limit of detection. However, treatment with interleukin-1 alpha (IL-1 alpha) + interferon-gamma (IFN-gamma) caused a significant rise in biopterin levels and induced NO synthesis. 2,4-Diamino-6-hydroxypyrimidine (DAHP), a selective inhibitor of GTP cyclohydrolase I (the rate-limiting enzyme for de novo BH4 synthesis), completely abolished the elevation in biopterin levels induced by IL-1 alpha + IFN-gamma. DAHP also caused a concentration-dependent inhibition of (IL-1 alpha + IFN-gamma)-induced NO synthesis. Similarly, N-acetylserotonin, an inhibitor of the BH4 synthetic enzyme sepiapterin reductase, blocked increases in biopterin levels as well as NO synthesis induced by IL-1 alpha + IFN-gamma. Sepiapterin, substrate for BH4 synthesis via the pterin salvage pathway, prevented this inhibition by DAHP or N-acetylserotonin, and this effect was blocked by methotrexate. Sepiapterin and, to a lesser extent, BH4 dose dependently enhanced (IL-1 alpha + IFN-gamma)-induced NO synthesis, suggesting that the concentration of BH4 limits the rate of NO production. Inducible NO synthase mRNA and GTP cyclohydrolase I mRNA were induced by IL-1 alpha + IFN-gamma in parallel. We thus demonstrate that BH4 synthesis is an absolute requirement for induction of NO synthesis by cytokines in cardiac myocytes.

Activation of R-Ras by Ras-guanine nucleotide-releasing factor

Ras-GRF/CDC25(Mm), mSos, and C3G have been identified as guanine nucleotide-releasing factors for Ras family proteins. We investigated in this study the guanine nucleotide-releasing activities of Ras-GRF, mSos, and C3G toward R-Ras, which shows high sequence similarity to Ras. Ras-GRF markedly stimulated the dissociation of GDP from R-Ras, and C3G also promoted the release of R-Ras-bound GDP. Under the same conditions, mSos little affected the reaction. When Ras-GRF and R-Ras were coexpressed in COS7 cells, the remarkable accumulation of the active GTP-bound form of R-Ras was observed. C3G also increased active R-Ras in COS7 cells, while mSos did not give any effect. These results indicated that Ras-GRF and C3G could activate R-Ras. Furthermore, the activation of R-Ras by Ras-GRF was enhanced when cells were treated with ionomycin, which is known to increase the intracellular calcium concentration. The examination of tissue distribution of R-Ras, Ras-GRF, and mSos by the reverse transcription-polymerase chain reaction revealed that Ras-GRF was expressed only in brain and testis, whereas R-Ras, C3G, and mSos were expressed rather ubiquitously. These findings raise the possibility that R-Ras is activated by Ras-GRF in brain and testis, and by C3G in other tissues, respectively.

Arginine-481 mutation abolishes ligand-binding of the AMPA-selective glutamate receptor channel alpha1-subunit

Arginine-481 is located in the putative agonist-binding region preceding the putative transmembrane segment M1 of the alpha1-subunit of the AMPA-selective glutamate receptor (GluR) channel. This amino acid is completely conserved among GluR proteins. A site-directed mutagenesis study using a baculovirus expression system showed that substitution of glutamate, glutamine and lysine for arginine-481 of the recombinant alpha1-subunit protein abolishes binding to [3H]AMPA completely. The present study provides the first direct experimental evidence that the conserved charged arginine-481 residue is essential, directly or indirectly, for the acquisition of ligand-binding activity by the receptor protein.

A randomized trial of cisplatin, vinblastine, and bleomycin versus cyclophosphamide, aclacinomycin, and cisplatin in epithelial ovarian cancer

After primary cytoreductive surgery, a randomized clinical trial was conducted in women with epithelial ovarian cancer to compare the impact on survival between PVB chemotherapy, consisting of cisplatin, vinblastine and bleomycin, and CAP chemotherapy, consisting of cyclophosphamide, aclacinomycin and cisplatin. There were 148 evaluable patients. One hundred and five patients with stage II, III and IV were analyzed in this study, 49 of them received PVB chemotherapy while the remaining 56 patients received CAP chemotherapy. Sixty-four patients fulfilled the criteria for clinical remission set by the Tokai Ovarian Tumor Study Group [Gynecol Oncol 1993;48:342-348]. The remission rate was 73 and 50% in the PVB and CAP groups, respectively, and showed a significant advantage for the PVB group (p = 0.0139). Moreover, the recurrence rate was 44% in the PVB group and 61% in the CAP group after clinical remission, although there was no significant difference between the two groups. The final survival rate was 32% in the PVB group and 24% in the CAP group. There was a significant difference of survival rate between both groups at 24 months (p = 0.0378) and 48 months (p = 0.0450), but finally no significant difference was found at 96 months (p = 0.0660). Compared to the CAP regimen, the PVB combination has a significantly higher efficacy in remission, but there was no significant difference in the long-term survival rate. Furthermore, multivariate analysis demonstrated that the PVB chemotherapy improved the survival, but it was not significant. The authors conclude that PVB chemotherapy may be more effective than CAP chemotherapy for epithelial ovarian cancer.

[A prospective controlled study of sairei-to in childhood IgA nephropathy with focal/minimal mesangial proliferation. Japanese Pediatric IgA Nephropathy Treatment Study Group]

To determine the effect of the Chinese herbal medicine, Sairei-to (TJ-114) in children with newly diagnosed IgA nephropathy showing focal/minimal mesangial proliferation, we undertook a prospective controlled study. One hundred and one patients were randomly assigned to receive Sairei-to for 2 years (group 1) or no drug for 2 years (group 2). Forty-six of the 50 patients in group 1 and 48 of the 51 patients in group 2 completed their trial. At entry, the two groups of patients did not differ in the clinical, laboratory and pathologic findings. At the end of the trial, urinary protein excretion and hematuria were significantly reduced in group 1, but were unchanged in group 2. Twenty-one group 1 patients (46%) had normal urine, but only 5 group 2 patients (10%) had normal urine at the end of the trial (p < 0.001). Blood pressure and creatinine clearance were normal at the end of the trial in all but one group 2 patient, who developed chronic renal failure. The present study demonstrates that 2-year Sairei-to treatment early in the course of disease is effective in children with IgA nephropathy showing focal/minimal mesangial proliferation.

Structures of genes encoding phospholipase A2 inhibitors from the serum of Trimeresurus flavoviridis snake

Inhibitors (PLIs) against snake venom gland phospholipases A2 (PLA2s) have been found in their sera. A cDNA encoding a PLI from Trimeresurus flavoviridis (Tf, habu snake, Crotalinae) serum, cPLI-A, was isolated from the Tf liver cDNA library and sequenced. Northern blot analysis with cPLI-A showed that PLIs are expressed only in liver. Genes for PLIs, gPLI-A and gPLI-B, were isolated from the Tf genomic DNA library and their nucleotide (nt) sequences were determined. The genes consisted of four exons and three introns, and exon 4 encoded the carbohydrate recognition domain (CRD)-like motif. Comparison of the nt sequences between gPLI-A and gPLI-B showed that these genes are highly homologous, including introns, except that exon 3 is rich in nonsynonymous nt substitutions which are almost four times as frequent as synonymous nt substitutions. This evolutionary feature of PLI genes is different from that of venom gland PLA2 isozyme genes in which nonsynonymous nt substitutions are spread over the entire mature protein-coding region.

A case of linear IgA disease: an immunofluorescent study using confocal laser scan microscopy

A 79-year-old Japanese woman presented with erythema and bullae on her trunk and limbs. Histological examination of the skin lesions showed subepidermal bullae and polymorphonuclear leukocyte infiltration into the papillary dermis. A direct immunofluorescent study showed the linear deposition of IgA, but not of IgG or IgM, in the basement membrane zone. Indirect immunofluorescence of the serum using confocal laser scan microscopy showed IgA, but not IgG, reactivity in the basement membrane zone. In double immunostaining experiments, IgA reactivity was also observed on the epidermal side; laminin 5 was detected on the dermal side.

A study on the biological significance of midregion and intact parathyroid hormone in hemodialysis patients

In this study, we investigated the relationship between the concentrations of intact parathyroid hormone (i-PTH) and midregion PTH (m-PTH) measured by an immunoradiometric assay and a radioimmunoassay, respectively, versus various demographic and biochemical parameters, bone mineral density (BMD) of the lumbar spine (LS) and radius, and the radiographic findings of osteosclerosis and aortic calcification in hemodialysis (HD) patients. m-PTH correlated positively and more significantly with serum calcium (Ca), serum phosphorus (P), Ca-P solubility products (Ca x P) and LS-BMD than i-PTH did (P = 0.024 vs. 0.531, 0.001 vs. 0.061, 0.0001 vs. 0.125, and 0.017 vs. 0.284, respectively). A positive correlation between the percent changes in serum P over the 1-month measurement period and those in m-PTH rather than in i-PTH was also observed (P = 0.021 vs. 0.869). These data indicate than m-PTH is distinct from i-PTH in its positive correlation with serum Ca, serum P, Ca [symbol: see text] P and LS-BMD in HD patients. Since m-PTH is known to consist mostly of the midregion and carboxyl-terminal fragments of PTH in HD patients, the present study suggests that these PTH fragments may be biologically significant in the patients in vivo.

Secretion of different types of gelatinases from cultured human keratinocytes

We investigated gelatinolytic enzymes derived from cultured human keratinocytes. Using a zymograph, we detected 92 kDa and 72 kDa gelatinases as major components and 83 kDa as a minor component from a conditioned cultured medium (BSL-K110, Kyokutoseiyaku Co.) of keratinocytes. After several passages, the 72 kDa band disappeared, and the 83 kDa band became dominant in another conditioned culture medium (K-GM, Kurashikibouseki Co.); these keratinocytes had a relatively differentiated appearance. These results suggest that some mechanism may regulate the secretion of selected types of gelatinase from keratinocytes under different conditions.

An Alu-linked repetitive sequence corresponding to 280 amino acids is expressed in a novel bovine protein, but not in its human homologue

A novel protein harboring a 280-amino acid region from an Alu-linked repetitive sequence (bovine Alu-like dimer-driven family) was isolated from a bovine brain S-100 fraction using monoclonal antibodies against a rat GTPase-activating protein that shares the same epitope. The protein has an apparent molecular mass of 97 kDa (p97). Western blot analysis using extracts prepared from various tissues showed p97 to be predominantly detected in brain and moderately in liver and lung. From sequence analysis of the cDNA encoding p97, it was found that the 840-base pair sequence homologous to a part of the bovine Alu-like dimer-driven family, which has never been shown to be expressed, occurs in the middle of the protein coding region. The protein also contains a pair of intramolecular repeats composed of 40 highly hydrophilic amino acids at the C terminus. Human cDNA homologous to p97 was cloned, and its nucleotide sequence demonstrates that the 840-base pair repetitive sequence and one of the intramolecular repeats are missing. We named p97 bovine BCNT after Bucentaur. These results show that bovine BCNT is a unique molecule and suggest that an analysis of the relationship between bovine bcnt and its human homologue may help further the understanding of gene organization and evolution.

Co-induction of nitric oxide and tetrahydrobiopterin synthesis in the myocardium in vivo

Induction of the inducible isoform of nitric oxide (NO) synthase (iNOS) in the myocardium is implicated as a mechanism in the development of cardiac depression in immune activated states associated with an enhanced release of cytokines, such as septic shock. We evaluated the in vivo synthesis of NO and tetrahydrobiopterin (BH4), a cofactor of NOS, in the heart tissue using a model of LPS injection in rats (LPS: 10 mg/kg, i.v.). In control rats, iNOS activity or iNOS mRNA in the heart was negligible. Three hours after LPS administration, a marked induction of iNOS mRNA and activity was observed in the heart. A significant increase in BH4 content and GTP cyclohydrolase mRNA abundance was also observed in the heart from LPS-treated rats. Our results demonstrate induction of NO synthesis and parallel increase in BH4 concentration in the heart of rats after LPS treatment in vivo and may provide molecular evidence responsible for the increased production of BH4 which may up-regulate iNOS activity in the heart in vivo.

Distribution of human herpesvirus 6 and varicella-zoster virus in organs of a fatal case with exanthem subitum and varicella

The distribution of human herpesvirus 6 (HHV-6) and varicella-zoster virus (VZV) was examined in autopsy samples from a fatal case with both virus infections. A 9-month-old boy developed convulsive seizures followed by macular skin rashes, rapidly progressed to brain death, and died 15 days after the onset, when signs of varicella were noted. An isolation of HHV-6 from blood and evaluation of antibody activities to various viral agents including HHV-6 were performed before his death. Postmortem examinations included: (i) isolation of HHV-6 and VZV from tissues or organs; (ii) detection of both virus antigens in tissues or organs by an indirect immunofluorescent assay using monoclonal antibodies to both viruses; (iii) amplification of both viruses and human herpesvirus 7 DNA sequences by a nested polymerase chain reaction assay; and (iv) endonuclease digestion of amplified products of HHV-6 DNA for differentation of variants A and B. Human herpesvirus 6 DNA was detected in peripheral blood mononuclear cells (PBMC) and plasma obtained at the eruptive stage but present only in PBMC 15 days after, indicating the primary infection with HHV-6, although the virus was not isolated from the same blood sample and a significant rise in the antibody titers to HHV-6 was not observed. Both virus antigens and DNA were detected in various tissues or organs obtained at autopsy, but only VZV was isolated from these samples, suggesting disseminated infection with both viruses in an infant. All the amplified products of HHV-6 DNA were variant B. Among the findings for the distribution of virus antigens, it was noteworthy that HHV-6 antigen was demonstrated in the endothelial cells of small vessels in the frontal lobe of the brain. There was no evidence of HHV-7 infection. These data indicate that the primary HHV-6 infection closely followed by the primary VZV infection had the potential hazard of an unexpected and apparently life-threatening event, in which disseminated infections with both viruses were noted in multiple tissues or organs including the brain.

Accelerated evolution of crotalinae snake venom gland serine proteases

Eight cDNAs encoding serine proteases isolated from Trimeresurus flavoviridis (habu snake) and T. gramineus (green habu snake) venom gland cDNA libraries showed that nonsynonymous nucleotide substitutions have accumulated in the mature protein-coding regions to cause amino acid changes. Southern blot analysis of T. flavoviridis genomic DNAs using two proper probes indicated that venom gland serine protease genes form a multigene family in the genome. These observations suggest that venom gland serine proteases have diversified their amino acid sequences in an accelerating manner. Since a similar feature has been previously discovered in crotalinae snake venom gland phospholipase A2 (PLA2) isozyme genes, accelerated evolution appears to be universal in plural isozyme families of crotalinae snake venom gland.

Retrospective study on the usefulness of radius and lumbar bone density in the separation of hemodialysis patients with fractures from those without fractures

We measured bone mineral density (BMD) at the lumbar spine (LS-BMD), 1/3 radius (1/3R-BMD), and ultradistal radius (UDR-BMD) in 59 men (4 with spine fractures and 4 with nonspine fractures) and 65 women (10 with spine fractures and 9 with nonspine fractures), all receiving maintenance hemodialysis (HD). The BMD at each site expressed absolutely in g/cm2 was significantly lower in women than in men (p = 0.0001). In men, the absolute and age-matched values of both 1/3R- and UDR-BMD were inversely and significantly correlated with the duration of HD, and with serum alkaline phosphatase and parathyroid hormone levels (p < 0.05), whereas such relationships were obscure in women. On the other hand, the absolute values of BMD at each site in women but not in men were inversely and significantly correlated with patient age (p < 0.001). In both sexes, R-BMD was significantly lower in both the spine and nonspine fracture groups than in the nonfracture group (p < 0.05 and p < 0.01, respectively), whereas the only significant difference in LS-BMD was that it was lower in women with spine fractures than in women without fractures, when expressed as its absolute value (p < 0.05). By receiver operating characteristic analyses, both the absolute and age-matched values of R-BMD were better than LS-BMD as a determinant of non-spine fracture histories, and were similar to absolute LS-BMD as a determinant of spine fracture histories. We conclude that R-BMD is more valuable than LS-BMD for discriminating HD patients with all types of fractures from those without fractures.

Accelerated evolution of snake venom phospholipase A2 isozymes for acquisition of diverse physiological functions

The nucleotide sequences of two cDNAs and four genes encoding Trimeresurus gramineus venom gland phospholipase A2 (PLA2) isozymes were determined and compared internally and externally with those encoding Trimeresurus flavoviridis venom gland PLA2 isozymes. It was revealed that the protein-coding regions are much more diversified than the 5' and 3' untranslated regions (UTRs) and the introns except for the signal peptide domain. The numbers of nucleotide substitutions per site (KN) for the UTRs and the introns were approximately one-quarter of the numbers of nucleotide substitutions per synonymous site (KS) for the protein-coding regions and were at the same level as the KN value of T. gramineus and T. flavoviridis TATA box-binding protein (TBP) genes, indicating that the protein-coding regions of PLA2 isozyme genes are unusually variable and that the UTRs including the introns of venom gland PLA2 isozyme genes have evolved at similar rate to those of non-venomous genes. The numbers of nucleotide substitutions per non-synonymous site (KA) values were close to or larger than the KS values for the protein-coding regions in venom gland PLA2 isozyme genes, indicating that the protein-coding regions of snake venom gland PLA2 isozyme genes have evolved via accelerated evolution. Furthermore, the evolutionary trees derived from the combined sequences of the 5' and 3' UTRs and the signal peptide domain of cDNAs were in accord with the consequences from taxonomy. In contrast, the evolutionary trees from the mature protein-coding region sequences of cDNAs and from the amino acid sequences showed random patterns. Estimations of nucleotide divergence of genes and the phylogenetic analysis reveal that snake venom group IJ PLA2 isozyme genes have been evolving under adaptive pressure to acquire new physiological activities.

[IGF-1 levels in elderly patients during perioperative period]

In the present study, concentrations of serum cortisol, ACTH, IRI, growth hormone and insulin-like growth factor 1 (IGF-1) were measured in 24 surgical patients. Patients were divided into two groups, elderly group (n = 12, age > or = 60, mean age: 68.4 +/- 1.3) and younger group (n = 12, age < 60, mean age: 44.5 +/- 3.5). The samples were taken before and immediately after surgery and on days 1 and 2 postoperatively. Serum levels of cortisol, ACTH, IRI and growth hormone increased significantly after surgery compared to baseline values but they showed no significant differences between elderly group and younger group. Only serum IGF-1 levels were significantly different between them. They were at consistently lower levels in elderly group throughout this study. In contrast, they decreased significantly after surgery, but high IGF-1 levels were maintained in younger group. Catabolic condition shown by negative nitrogen balance is induced after surgery. IGF-1 has potential anabolic effect in human. The pharmacological approach using IGF-1 in the elderly surgical patients will be necessary in order to improve their overall conditions before and after surgery in the future.

Characterization of monoclonal antibodies recognizing human merosin and their use in affinity purification of native merosin

Two monoclonal antibodies (MAbs) to human placenta laminin (pl-LAM), 1D8 (IgG1) and 6G5 (IgG2b) were generated and shown by ELISA and immunoblot analysis to recognize only native pl-LAM, but not denatured, reduced pl-LAM or mouse EHS laminin. Intact pl-LAM was easily isolated and purified in large scale from human placenta by 1D8-conjugated affinity chromatography. Electrophoretic analysis of the purified pl-LAM revealed the presence of a major 750-kDa component composed of 320-, 220-, and 200-kDa polypeptides and a minor 800-kDa component composed of 320-, 240-, and 220-kDa polypeptides. Neither molecule had a 400-kDa component corresponding to the A chain. It has already been shown that the 320-kDa polypeptide is identical to the M chain of human merosin (Hori et al. J. Biochem. 1994;116:1212-1219). Electron microscopy revealed that isolated merosin was composed of three short arms and one long arm. By immunohistochemistry, MAbs showed positive staining in human adult kidney and liver. These results indicate that these MAbs recognize only native merosin and can be used to study merosin structure and function by rapid purification of native merosin and by immunohistochemical analysis.

Remodeling of HDL containing apoA-I but not apoA-II (LpA-I) by lipoprotein-deficient plasma and hepatic lipase: its effect on the structure and cellular cholesterol-reducing capacity of LpA-I

We investigated the effects of lipoprotein-deficient plasma (LDP) and hepatic lipase (HL) on the structure and cellular cholesterol-reducing capacity of subclasses of LpA-I (HDL containing apoA-I but not apoA-II). LpA-I is composed of large (11.1 nm; L-LpA-I), medium (8.8 nm: M-LpA-I) and small (7.7 nm: S-LpA-I) particles. L-LpA-I and M- and S-LpA-I combined (MS-LpA-I) were incubated with lipoprotein-deficient plasma and HL in the presence of very low density lipoprotein (VLDL). After incubation of L-LpA-I, the proportions of cholesteryl esters and phospholipids decreased and as a result, the proportion of protein increased. The remodeled L-LpA-I particles were generally smaller (spherical: 7.8-8.8 nm) in diameter. A small number of disc-shaped particles were also found in electron photomicrographs. These changes coincided with a slower electrophoretic mobility of remodeled L-LpA-I. In the case of MS-LpA-I, only the proportion of free cholesterol increased after incubation, and MS-LpA-I particles did not change in size. The cholesterol-reducing capacities of remodeled L-LpA-I and MS-LpA-I from macrophage foam cell were slightly higher and lower than their respective original counterparts, although neither of these differences was statistically significant. These results suggest that LDP and HL mainly contribute to the remodeling of L-LpA-I particles, and may not affect the cellular cholesterol-reducing capacity of these particles.

[Anesthetic management of a patient with erythroderma]

We gave anesthesia to a patient with erythroderma for distal partial gastrectomy. Erythroderma is an inflammatory disorder in which generalized erythema and scaling occur, either as a specific phase of processes such as T cell lymphoma, as a manifestation of underlying malignancy or in the absence of preexisting diseases. Severe cases of erythroderma may involve disturbances in the cardiovascular, thermoregulatory and metabolic systems which make the management of general anesthesia difficult. Systemic scale also causes a difficulty in placing ECG monitor electrodes and endotracheal tube. In the present case, dyspnea and asthmatic bronchitis occurred postoperatively. Therefore, in a patient with erythroderma, we recommend careful systemic management throughout the perioperative period.

Activation of Ras and protection from apoptotic cell death by BDNF in PC12 cells expressing TrkB

A clonal deoxyribonucleic acid (cDNA) clone of mouse trkB was expressed in cells of the rat PC12 pheochromocytoma cell line. The transformants followed apoptotic death upon serum deprivation. The addition of brain-derived neurotrophic factor (BDNF) to the culture medium supported the survival and neurite extension of the transformants in a serum-free condition. A Trk-family-specific protein kinase inhibitor, K-252a, inhibited the survival and neurite extension of the transformants in the presence of BDNF. BDNF activated autophosphorylation of trkB and caused the accumulation of a guanosine triphosphate (GTP)-bound form of Ras, both of which effects were also inhibited by K-252a. These results suggested that BDNF-triggered Ras activation is important for the survival and neuronal differentiation of PC12 cells in a serum-free condition.

cDNA cloning and chromosomal mapping of a novel human GAP (GAP1M), a GTPase-activating protein of Ras

We have previously isolated a novel Ras GTPase-activating protein (Ras GAP), Gap1m, from rat brain. Gap1m is considered to be a negative regulator of the Ras signaling pathways, like other Ras GAPs, neurofibromin, which is a gene product of the neurofibromatosis type I gene, and p120GAP. In this study we have isolated a human cDNA of this Gap and mapped the gene. The gene encodes a protein of 853 amino acids that shows 89% sequence identity to rat Gap1m. The human gene was mapped to chromosome 3 by PCR analysis on a panel of human-mouse hybrid cells. FISH analysis refined the location of the gene further to 3q22-q23.

Mucinous carcinoma of the ovary. Clinicopathologic analysis

Since the incidence of mucinous carcinoma of the ovary is relatively low, with only small numbers of cases at any institution, detailed clinicopathologic studies on the prognosis and the care of patients with mucinous carcinoma are missing. Forty-four patients with mucinous carcinoma were histopathologically subclassified into endocervical (n = 8) and intestinal types (n = 36), and studied for clinical manifestations. All tumors of the endocervical type were stage I, whereas 14 intestinal-type tumors were stage II or higher (p < 0.05). Stromal invasion was not observed in 14 of 44 tumors, 13 of which were stage I. Analysis of prognostic factors disclosed that the clinical stage, maximum residual tumor diameter, volume of ascites, stromal invasion, and preoperative CA125 and CA19-9 levels significantly affected prognosis. However, multivariate analysis (stepwise regression) showed that the only significant factor was clinical stage (p < 0.004). In conclusion it is believed that, pathologically, the endocervical-type mucinous carcinoma is not as aggressive as the intestinal-type cancer. The clinical stage was found to be a significant prognostic factor even by multivariate analysis, and the prognosis at stages III and IV was unfavorable compared to stages I and II.

Accelerated evolution of Trimeresurus okinavensis venom gland phospholipase A2 isozyme-encoding genes

Three Trimeresurus okinavensis (To; himehabu snake, Crotalinae) venom gland phospholipase A2 (PLA2) isozymeencoding genes, gPLA2-o1, gPLA2-o2 and gPLA2-o3, were isolated from its genomic DNA library. The nucleotide (nt) sequence analysis revealed that two of the three genes (gPLA2-o2 and gPLA2-o3) occasionally have been converted to inactivated genes by introduction of one base insertion or substitution. It was confirmed from Southern blot analysis that the To haploid genome contains only three venom gland PLA2 isozyme genes herein isolated. Comparison of these genes showed that nonsynonymous nt substitutions have occurred more frequently than synonymous nt substitutions in the protein-coding regions, except for the signal-peptide coding domain, implying that To venom gland PLA2 isozyme genes have evolved via accelerated evolution. Such an evolutionary feature of To venom gland PLA2 isozyme genes proves the general universality of accelerated evolution previously drawn for venom gland PLA2 isozyme genes of other crotalinae snakes. The variability in the mature protein-coding regions of three To venom gland PLA2 isozyme genes appears to have been brought about by natural selection for point mutations.

Ras-regulated hypophosphorylation of the retinoblastoma protein mediates neuronal differentiation in PC12 cells

To investigate the role of the retinoblastoma protein pRB in neuronal differentiation, we have measured the accumulation of hypophosphorylated pRB in PC12 cells stimulated by nerve growth factor (NGF). NGF induced the accumulation of hypophosphorylated pRB within 30 min and the level peaked after 12 h. Viral Kiras, cyclic AMP (cAMP), and 12-O-tetradecanoylphorbol 13-acetate (TPA) also induced the hypophosphorylation of pRB, but epidermal growth factor and interleukin-6 did not. The extent of hypophosphorylation of pRB correlated well with the capacity of these factors to stimulate neurite outgrowth. The constitutively activated Ras induced persistent shift of the phosphorylation state of pRB toward hypophosphorylation. A dominant negative form of cHa-Ras suppressed significantly induction of the hypophosphorylation of pRB by NGF, but not by cAMP. Taken together, these results suggest that the hypophosphorylation of pRB triggered by NGF is mediated by a Ras-dependent pathway. Furthermore, microinjection of a monoclonal antibody specific for the hypophosphorylated form of pRB blocked the neurite outgrowth initiated by NGF. These results suggest a crucial role of pRB in withdrawal of cells from the cell cycle and in neuronal differentiation of PC12 cells.

Immunolocalizations of human gelatinase (type IV collagenase, MMP-9) and TIMP (tissue inhibitor of metalloproteinases) in normal epidermis and some epidermal tumors

The matrix metalloproteinases (MMPs) MMP-2 and MMP-9 (gelatinases) have been suggested as serving an important role in cleaving the basement membrane structure. Tissue inhibitors of metalloproteinases TIMPs (particularly TIMP-1) are known to inhibit MMPs. Based on this background, we raised monoclonal antibodies against human gelatinase (MMP-9) and human recombinant TIMP (TIMP-1), and immunostained these two components in skin from patients with squamous cell carcinoma (SCC), Bowen's disease (BD) and keratoacanthoma (KA). MMP-9 showed positive staining mainly in the granular layer of normal epidermis. In some cases of SCC and BD, MMP-9 showed positive staining in the dysplastic lesions even in the basal layer. TIMP showed a thorough positivity in normal epidermis. Unstained regions with this antibody were observed in SCC and BD. These results suggest that an altered staining pattern for MMP-9 and TIMP may be closely related to the malignant transformation of SCC and BD.

Ursodeoxycholic acid inhibits the induction of nitric oxide synthase

Ursodeoxycholic acid was recently recognized as an effective agent in the treatment of primary biliary cirrhosis. Since the beneficial effect of ursodeoxycholic acid therapy appears to be mediated in part by an immune mechanism, we evaluated the effects of ursodeoxycholic acid on the synthesis of nitric oxide (NO), elevated production of which could be important in the pathogenesis of autoimmunity. Ursodeoxycholic acid (0.1-1000 microM) inhibited NO production by bacterial lipopolysaccharide-activated J774 macrophages in a concentration-dependent fashion, but the cytotoxicity was also evident at higher concentrations (250 and 1000 microM). Ursodeoxycholic acid did not have any effect on the activity of NO synthase that had already been induced. Treatment with lipopolysaccharide led to a significant expression of NO synthase mRNA that was significantly reduced by ursodeoxycholic acid. Findings indicated that ursodeoxycholic acid inhibited NO synthesis by inhibiting the induction of NO synthase, rather than its catalytic activity. Ursodeoxycholic acid therapy may exert a beneficial effect, in part, by attenuating the production of NO.

The induction of metachromasia and circular dichroism of coomassie brilliant blue R-250 with collagen and histone H1 is due to the low content of hydrophobic amino acid residues in these proteins

Collagen and histone H1 are stained a pink-red color with Coomassie Brilliant Blue R-250 (Coomassie R) instead of the blue color of most proteins after SDS-PAGE. Spectrophotometrically, this metachromasia was characterized by an increase in the absorbance at 535 nm and a decrease in the absorbance at 600 nm. The ratio of the absorbance at 535 nm to that at 600 nm ranged from 1.5 to 2.5 for the pink-red-stained proteins and was about 1 for the blue stained proteins. In their amino acid composition, the pink-red-stained proteins collagen and histone H1 contained less than 11% of hydrophobic amino acid residues, whereas the five blue-stained proteins examined contained more than 25% of such residues. Collagen and histone H1 also induce circular dichroism (CD) of Coomassie R in the visible region with a different CD spectrum. In the case of native collagen, a CD (+) band at 530 nm with 10(5) molar ellipticity was observed, while the denatured collagen showed a CD(-) band at 530 nm. When the amino groups of the amino acid residues in collagen and histone H1 were converted into hydrophobic groups by fluorescamine treatment, these proteins stained bluer than pink-red and the induced CD was a lower intensity. This is the first report of the metachromatic interaction between a protein and Coomassie R that is accompanied by CD induction. This report also suggests that the induction of metachromasia and CD of Coomassie R was due to the low content of hydrophobic amino acid residues in the peptides.

Dynamic regulation of striatal dopaminergic grafts during locomotor activity

The present experiment was designed to estimate the neurochemical activity of dopaminergic grafts in hemiparkinsonian model rats during locomotion and to examine the functional importance of dynamic regulation of the grafted neurons in the host brain. Rats were trained to run on a straight treadmill at various speeds (300, 660, 1200, 1800 cm/min), and extracellular dopamine (DA) and its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), were measured by in vivo microdialysis during and after running. Grafted rats were divided into two groups depending on their running ability and data were compared with those of normal and lesioned controls. Although the tonic level of extracellular DA in grafted rats recovered to 70% of control, levels of DOPAC and HVA remained 15-20% of controls. A small number of grafted rats showed full recovery in treadmill running tasks. In these animals, the percentage increase in DOPAC and HVA showed similar time courses and magnitudes as those in normal rats. Most grafted rats showed partial recovery in locomotor ability. The percentage increase in DOPAC and HVA in these animals remained at a lower level than that in normal rats, though the tonic levels of DA, DOPAC and HVA were not lower than those of fully recovered rats. Data suggest that grafted DAergic cells in functionally well recovered rats were dynamically regulated in the host brain in an actual behavior and that well-controlled release of DA might be involved in the recovery of complex motor behavior, such as high speed locomotion.

Relation between perinatal factors and outcome of very low birth weight infants

In order to better understand the effect of obstetric management on the prognosis of very low birth weight (VLBW) fetuses, we retrospectively studied perinatal factors and the outcome of two hundred twenty-eight VLBW infants without major anomaly excluding cases of multiple pregnancy. The frequency of malpresentation were significantly high in the early neonatal death group (p < 0.05) and in the cerebral palsy/mental retardation (CP/MR) group (p < 0.01). A stepwise regression analysis for the CP/MR detected dependent variables as malpresentation, use of tocolytic agents (beta(2)-stimulant plus MgSO4) and pH < 7.20 in cord artery. Delivery method was not a dependent variable for the early neonatal death or the CP/MR. We analyzed a relation between fetal presentation-delivery method, and the prognosis. Among four groups (cephalic-vaginal, cephalic-cesarean, breech-vaginal, breech-cesarean), the cephalic-vaginal group had the lowest incidence of the poor prognosis (death and major handicap) where the breech-vaginal had the highest incidence. Breech groups (vaginal plus cesarean) had significantly high incidence of the poor prognosis when compared with that of cephalic groups (vaginal plus cesarean) (p < 0.05). Significant difference of the prognosis between the cephalic-vaginal group and the cephalic-cesarean group was not observed. These findings suggest that the delivery method is not a risk factor, but the malpresentation itself may be a risk factor for the poor prognosis of VLBW infants.

Effects of a factor derived from polymorphonuclear leukocytes on the growth and collagen metabolism in normal and scleroderma skin fibroblast cultures

Effects of a factor (15 kDa) derived from polymorphonuclear leukocytes (PMNs) on the growth and collagen metabolism of normal and scleroderma skin fibroblasts in culture were investigated. Skin fibroblasts from papillary, reticular or whole dermis of 5 patients with scleroderma and 7 normal controls were cultured in the presence or absence of PMN factor. The factor affected skin fibroblasts, (i) to stimulate cell proliferation, (ii) to stimulate collagenase production as observed by its functional activity, but (iii) to suppress collagen production with little effect on collagen types at a stage before the translational level. Scleroderma fibroblasts were less susceptible to the factor than normal fibroblasts in terms of cell proliferation and protein synthesis including collagen. Stimulation of cell proliferation by the factor was higher with reticular cells than papillary cells, while stimulation of collagenase production was inversely high in papillary cells and little stimulation was noted with reticular cells. Suppression of collagen production was also eminent in papillary cells, compared with that in reticular cells. These results suggest that PMNs function at the inflammatory stage in shifting tissue metabolism to a catabolic phase by releasing a factor which stimulates connective tissue cells, and that decreased susceptibility of scleroderma cells and reticular cells to PMN factor may provide for a positive factor in the accumulation of collagen in the reticular dermis of scleroderma skin.

Immunolocalization of human gelatinase (type IV collagenase, MMP-9) and tissue inhibitor of metalloproteinase 1 in Hailey-Hailey and Darier's diseases

BACKGROUND

The formation of lacunae and acantholysis as well as dyskeratosis are characteristic features of Hailey-Hailey disease (HHD) and Darier's disease (DD). Matrix metalloproteinases (MMPs) and their inhibitors like tissue inhibitors of metalloproteinases (TIMPs) have been thought to play major roles in the tissue metabolism.

OBJECTIVE

The aim of this study was to investigate the role of MMP-9 and TIMP-1 in HHD and DD.

METHODS

We examined localizations of these two molecules by immunostaining using specific monoclonal antibodies.

RESULTS

MMP-9 was positively stained in dyskeratotic or detaching cells around lacunae in HHD and DD. TIMP-1 showed a positive staining pattern throughout the epidermis.

CONCLUSION

MMP-9 might be involved in the pathophysiological process of HHD and DD in the presence of TIMP-1.

[Heterogeneity of GTPase-activating proteins for Ras in the regulation of Ras signal transduction pathway]

The proto-oncogene ras is an essential gene for the growth and the differentiation for various types of cells. Ras, ras gene product, is a GTP binding protein which controls the signal transduction by GTP hydrolysis. The ras gene is frequently activated by point mutations in various types of human cancers, which results in a decrease in the GTPase activity of its product. A GTPase-activating protein p120 (p120GAP) was identified as a factor which stimulates the GTPase of normal ras gene product p21 but not of the mutated. An NF1 gene was identified as a gene whose loss of function causes an onset of human disorder, neurofibromatosis type I. The NF1 gene encodes a protein which contains a region with a similarity to the catalytic domain of p120GAP. We recently purified a novel Ras GAP whose molecular weight and immunogenecity are different from those of p120GAP and NF1. We named the novel mammalian Ras GAP as Gap1m. Isolation and sequencing of Gap1m cDNA revealed that Gap1m is indeed a novel Ras GAP. We also succeeded in isolation of another novel Ras GAP gene, GapIII/Gap1IP4BP, which is closely related to Gap1m. Recently, it is shown that GapIII/Gap1IP4BP binds inositol-tetrakis phosphate compounds. The overview of these Ras GAP molecules is described.

The SH2 domain of Shc suppresses EGF-induced mitogenesis in a dominant negative manner

Recently, we have shown that an EGF-R-mutant lacking the autophosphorylation sites phosphorylates Shc and retains mitogenic activity. In this report, we have shown that in these cells, in response to EGF, Ras is fully activated with formation of the tyrosine-phosphorylated Shc-Grb2-mSOS complex without the receptor. This pointed out the importance of Shc in EGF-induced Ras activation. To investigate the mechanism of tyrosine phosphorylation of Shc by EGF-R, we carried out in vitro kinase assays using immunoprecipitated EGF-R and bacterially-expressed Shc proteins as substrates. The EGF-R phosphorylated Shc, but not the Shc SH2 mutant, lacking binding ability for phosphotyrosine. This suggests that intact Shc SH2 is essential for the full-length Shc to become phosphorylated, probably by inducing a conformational change in Shc. Thus a Shc SH2 peptide may inhibit competitively Shc phosphorylation. We microinjected the Shc SH2 domain into NIH3T3 cells overexpressing the EGF-R. Microinjected Shc SH2 greatly suppressed EGF-induced DNA synthesis. But microinjection of neither the Shc SH2 mutant nor PLC-gamma 1 SH2 had any effect. This suppressing effect was rescued by comicroinjection of the full-length Shc, suggesting Shc SH2 specifically suppressed the Shc pathway. Thus we concluded Shc phosphorylation is crucial, whereas receptor autophosphorylation is dispensable, in EGF-induced mitogenesis.

An abnormal fibrinogen Fukuoka II (Gly-B beta 15-->Cys) characterized by defective fibrin lateral association and mixed disulfide formation

A dysfibrinogenemia was attributable to a single amino acid substitution from glycine to cysteine at residue 15 of the B beta chain in a fibrinogen molecule designated as fibrinogen Fukuoka II. The fibrinogen Fukuoka II showed prolonged thrombin and reptilase times and impaired fibrinopeptide B release by thrombin, resulting in abolition of fibrin monomer repolymerization under physiological conditions. Repolymerization of the des-(B beta 1-42)-fibrin monomers, however, was not distinguished from the normal pattern of des-(B beta 1-42)-fibrin monomers, suggesting that no other abnormality existed in fibrinogen Fukuoka II. Although an additional cysteine was substituted at residue 15 of the B beta chain, fibrinogen Fukuoka II had no free sulfhydryl group within the molecule. Instead, fibrinogen Fukuoka II formed a disulfide bond with cysteine, albumin, another mutated B beta chain within the same molecule, or intermolecular dimeric fibrinogen Fukuoka II. The mutation in fibrinogen Fukuoka II was the same as that in fibrinogen Ise published previously (Yoshida, N., Wada, H., Morita, K., Hirata, H., Matsuda, M., Yamazumi, K., Asakura, S., and Shirakawa, S. (1991) Blood 77, 1958-1963). Fibrinogen Ise, however, has been described as having prolonged thrombin time but normal reptilase time. Reasons for the discrepancy were not clear. Analysis of the B beta 1-42 fragment showed that fibrinogen was heterogeneous at position 31 of the B beta chain with respect to proline or hydroxyproline.

Identification of Rap1 as a target for the Crk SH3 domain-binding guanine nucleotide-releasing factor C3G

C3G, which was identified as a Crk SH3 domain-binding guanine nucleotide-releasing factor, shows sequence similarity to CDC25 and Sos family proteins (S. Tanaka, T. Morishita, Y. Hashimoto, S. Hattori, S. Nakamura, M. Shibuya, K. Matuoka, T. Takenawa, T. Kurata, K. Nagashima, and M. Matsuda, Proc. Natl. Acad. Sci. USA 91:3443-3447, 1994). The substrate specificity of C3G was examined by in vitro and in vivo experiments. C3G markedly stimulated dissociation of bound GDP from Rap1B but marginally affected the same reaction of other Ras family proteins (Ha-Ras, N-Ras, and RalA). C3G also stimulated binding of GTP-gamma S [guanosine 5'-3-O-(thio)triphosphate] to Rap1B. When C3G and Rap1A were expressed in COS7 cells, marked accumulation of the active GTP-bound form of Rap1A was observed, while Sos was not effective in the activation of Rap1A. These results clearly show that C3G is an activator for Rap1. Furthermore, expression of C3G with a membrane localization signal in a v-Ki-ras transformant, DT, induced a reversion of the cells to the flat form, possibly through the activation of endogenous Rap1.

Localization and expression of phospholipases A2 in Trimeresurus flavoviridis (habu snake) venom gland

The localization and expression profiles of phospholipases A2 (PLA2s) in Trimeresurus flavoviridis venom gland were studied by means of in situ hybridization and immunohistochemical techniques. Venom gland cells are tightly arrayed in a single layer along the inlet-like lumens in which venom proteins are stored. mRNAs for PLA2s were detected at the high level in cytoplasm. Using the immunohistochemical technique with polyclonal anti-Asp-49-PLA2 antibody, Asp-49-PLA2 and, possibly, its isozymes were detected in intracellular granules and in venom lumens. The intracellular granules containing PLA2 proteins appear to be transferred from the nucleus towards the outer membrane facing the lumen, and then to be secreted.

Requirement of Saccharomyces cerevisiae Ras for completion of mitosis

In the yeast Saccharomyces cerevisiae, Ras regulates adenylate cyclase, which is essential for progression through the G1 phase of the cell cycle. However, even when the adenosine 3',5'-monophosphate (cAMP) pathway was bypassed, the double disruption of RAS1 and RAS2 resulted in defects in growth at both low and high temperatures. Furthermore, the simultaneous disruption of RAS1, RAS2, and the RAS-related gene RSR1 was lethal at any temperature. The triple-disrupted cells were arrested late in the mitotic (M) phase, which was accompanied by an accumulation of cells with divided chromosomes and sustained histone H1 kinase activity. The lethality of the triple disruption was suppressed by the multicopies of CDC5, CDC15, DBF2, SPO12, and TEM1, all of which function in the completion of the M phase. Mammalian ras also suppressed the lethality, which suggests that a similar signaling pathway exists in higher eukaryotes. These results demonstrate that S. cerevisiae Ras functions in the completion of the M phase in a manner independent of the Ras-cAMP pathway.

Splicing mutations in the COL4A5 gene in Alport's syndrome: different mRNA expression between leukocytes and fibroblasts

The COL4A5 gene from 40 patients with Alport's syndrome was examined using single-strand conformation substitution at the acceptor site (-2) of intron 50 and a G-to-C substitution at the donor site (+1) of intron 47, respectively. The transcript in peripheral leukocytes from the former had a 10-nucleotide deletion. This shortened transcript was derived from abnormal splicing in a cryptic acceptor site within exon 51. This could be translated into a protein with an alteration of three amino acids followed by premature termination, which eliminated 23 amino acids from the carboxyl end. Gene tracking revealed that the mother and a brother carried the mutant allele. In the latter, the transcript in leukocytes was normal, but that in cultured skin fibroblasts showed skipping of exon 47, the result being that 71 amino acids were absent. Glomerular basement membrane from the patient did not react with the anti-alpha 5(IV) antibody. His maternal grandmother, mother, and a sister, all with abnormal urinalysis, carried the mutant allele. Thus, the appearance of exons of the COL4A5 gene in leukocytes may differ from that in fibroblasts. If kidney mRNA is not available, mRNAs from cultured skin fibroblasts, in addition to leukocytes, can be used for gene analysis in subjects with Alport's syndrome.