Molecular mechanisms of the activation of maturation-promoting factor during goldfish oocyte maturation

Oocyte maturation is triggered by the activation in the oocyte cytoplasm of maturation-promoting factor (MPF), which consists of cdc2 (a catalytic subunit) and cyclin B (a regulatory subunit). Immature goldfish oocytes contain only inactive monomeric 35-kDa cdc2 and do not stockpile cyclin B. In maturing oocytes, activation of cdc2 is associated with its Thr161 phosphorylation and mobility shift on SDS-PAGE from 35 to 34 kDa after binding to cyclin B. Using mutant cdc2, we show that Thr161 phosphorylation is required for both the downward shift and the kinase activation. Since cdc2 Tyr15 is not phosphorylated after binding to cyclin B, it does not require dephosphorylation. This situation is obviously different from that in immature Xenopus oocytes, in which the cdc2-cyclin B complex preexists with cdc2 phosphorylated on both Tyr15 and Thr161, thereby requiring Tyr15 dephosphorylation catalyzed by cdc25 phosphatase for MPF activation. These results indicate that these species employ different mechanisms of MPF activation during oocyte maturation, although the final molecular structure of the active MPF (cdc2 bound to cyclin B and phosphorylated on Thr161) is identical.

Developmental toxicity study of piperonyl butoxide in CD rats

Piperonyl butoxide was administered to pregnant rats by gavage at a level of 0 (control), 630, 1065, and 1800 mg/kg bw on days 11-12 of gestation. The animals were killed on day 20 of gestation. Average maternal body weight gain (gestational days 11-20) was significantly reduced in the 1065 and 1800 mg/kg bw groups. Total resorption rate was significantly increased in the 1800 mg/kg bw group and those effects were significantly dose-related. The average fetal body weight of each sex was significantly reduced in the 1065 and 1800 mg/kg bw groups. External limb deformity (oligodactyly, syndactyly, and polydactyly) was significantly increased in the 1065 and 1800 mg/kg bw groups in a dose-related manner. The dose levels of piperonyl butoxide in the present study produced limb deformities in rats.

Abnormally phosphorylated tau in SY5Y human neuroblastoma cells

In Alzheimer disease (AD) the microtubule associated protein (MAP) tau is hyperphosphorylated at several sites. In the present study, like AD tau, tau in the human neuroblastoma SH-SY5Y was found to be hyperphosphorylated, at Ser-199/202, Thr-231, Ser-396 and Ser-404. However, in contrast to AD, the tau in SY5Y cells was not hyperphosphorylated at Ser-235 and there was only one tau isoform. Quantitative analysis revealed that approximately 80% of the SY5Y-tau was phosphorylated at Ser-199/202. The phosphorylated tau was deposited in perikarya and processes of the cells whereas most of the unphosphorylated (at Ser-199/202) tau was localized in the nucleus. Tau from the cell lysates did not bind to taxol-stabilized microtubules. In contrast, MAP1b and MAP2 from cell lysates bound to stabilized microtubules in vitro and were associated to the microtubule network in situ. Phosphorylation of tau at high levels, its inactivity with microtubules and its accumulation in SY5Y cells provide for the first time a cell model of cytoskeletal changes seen in AD.

Subtypes of endothelin ETA and ETB receptors mediating tracheal smooth muscle contraction

In the isolated rabbit trachea, endothelin (ET)-1, ET-3 and the selective ETB receptor agonists, IRL 1620 and sarafotoxin S6c (STXc), induced contraction with EC50 of 2-9 nM. An ETA1 receptor antagonist, BQ-123, was ineffective whereas desensitization of the ETB receptor strongly antagonized the effect of ET-3, IRL 1620 and STXc. An ETB1 receptor antagonist, RES-701-1, antagonized the effects of ET-3 and IRL 1620 whereas the effect of STXc was antagonized by an ETB2 receptor antagonist, BQ-788. In the ETB-desensitized trachea, only ET-1 induced large contraction that was partially antagonized by BQ-123. These results suggest that ET induces tracheal contraction by activating multiple ET receptors: the ET-1-selective ETA (BQ-123-sensitive ETA1 and insensitive ETA2 subtypes) and the isopeptide-nonselective ETB receptors (RES-701-1-sensitive ETB1 and insensitive ETB2 subtypes).

Genotype and phenotype of severe mitochondrial cardiomyopathy: a recipient of heart transplantation and the genetic control

Comprehensive analyses of mitochondrial (mt)DNA of a recipient of heart transplantation at age 7 because of severe cardiomyopathy revealed three germ line point mutations, each one in the 12S rRNA gene, in the CO1 gene and in the cytochrome b gene, respectively. As the somatic mutation, extensive fragmentation of mtDNA associated with 212 kinds of deletions was detected in contrast to 5 kinds in an age-matched negative control. A recipient's positive control having almost the same base-substitutions and mutations with the recipient except one in the CO1 gene also developed severe cardiomyopathy died at age 20. The close relation between phenotype and mtDNA genotype provides the basis of our understanding of cell death and premature ageing.

Prevention of hepatic metastasis of human colon cancer by angiogenesis inhibitor TNP-470

The antimetastatic effect of a potent angiogenesis inhibitor, O-(chloroacetyl-carbamoyl)fumagillol (TNP-470), was investigated in nude mice implanted with human colon cancer. Small pieces of tumors from three established human colon cancer cell lines (TK-3, TK-4, and TK-9), which were maintained in nude mice, were implanted into the cecal wall of nude mice via a small incision in the serosa. TNP-470 (20 or 30 mg/kg) was given s.c. every other day from day 10 after implantation, and the mice were sacrificed after 6 weeks. There was no difference in the weight of the implanted tumors (control group: 0.45 +/- 0.29 g versus treated group: 0.49 +/- 0.27 g). An antimetastatic effect of TNP-470 was clearly demonstrated in a dose-dependent manner. In the mice given 20 mg/kg TNP-470, liver metastasis developed in 3 of 10 cases. In the 30-mg/kg group, metastasis developed in only 1 of 17 mice, while it developed in 22 of 32 mice of the control group. The number of metastatic foci was significantly less in the treated groups. TNP-470 effectively prevented liver metastasis, however, but had no effect on the growth of the primary tumor. These results indicate that the angiogenesis inhibitor TNP-470 has a strong inhibitory activity against in vivo hepatic metastasis of human colon cancer.

Hepatitis B virus strains with mutations in the core promoter in patients with fulminant hepatitis

OBJECTIVE

Fulminant hepatitis B can be induced by hepatitis B virus (HBV) strains with mutations in the precore region that cannot encode hepatitis B e antigen (HBeAg). Such mutations are rarely seen in HBV DNA clones from patients with fulminant hepatitis B in the United States and France. Thus, the other mutations in HBV strains causing fulminant hepatitis B need to be identified.

DESIGN

Retrospective clinical, serologic, and molecular biological studies of patients with fulminant hepatitis B.

SETTING

University and city hospitals in Japan.

PATIENTS

43 patients with fulminant hepatitis B.

MEASUREMENTS

The precore region coding for a part of the HBeAg precursor and the core promoter regulating the transcription of precore messenger RNA were sequenced in HBV DNA clones.

RESULTS

A point mutation from G to A at nucleotide 1896 in the precore region was detected in 519 (98%) of 529 HBV DNA clones from 38 patients. Two point mutations in the core promoter, from A to T at nucleotide 1762 and from G to A at nucleotide 1764, were detected in all 130 clones from the remaining 5 patients, who did not have mutations in the precore region, and in 20 (63%) of 32 clones from a patient with chronic hepatitis B who had transmitted HBV to 1 of these other 5 patients. Mutations in the core promoter were also detected in clones from 26 (68%) of the 38 patients with the precore mutation at nucleotide 1896. Neither HBeAg nor antibody to HBeAg was detected in 37 (90%) of the 41 patients tested.

CONCLUSIONS

In Japan, fulminant hepatitis B is closely associated with HBV strains that do not produce HBeAg because of mutations in the precore region, which affect translation of HBeAg, or because of mutations in the core promoter, which affect transcription of the HBeAg coding region.

NG-nitro-L-arginine protects against hypoxia/hypoglycemia-induced decrease in CA1 presynaptic spikes in rat hippocampal slices

The effects of nitric oxide (NO) synthase inhibitors on the hypoxia/hypoglycemia-induced decrease in CA1 presynaptic fiber spikes elicited by stimulation of the Schaffer collaterals were investigated using rat hippocampal slices. Drugs were added to normal medium for 10 min before incubation under hypoxic/hypoglycemic conditions (15 min), and after a 3-h washout, the CA1 presynaptic potential was measured. Treatment with NG-nitro-L-arginine methyl ester but not with NG-nitro-D-arginine methyl ester produced a concentration-dependent attenuation of the hypoxia/hypoglycemia-induced decrease in presynaptic fiber spikes. In contrast, treatment with precursors of NO in the arginine-to-NO pathway, such as sodium nitroprusside, S-nitro-N-acetylpenicillamine and N-morpholino sydnonimine exacerbated the 15-min hypoxia/hypoglycemia-induced decrease in the CA1 presynaptic potential. The neuroprotective effect of NG-nitro-L-arginine methyl aster was significantly attenuated by co-treatment with L-arginine. The present results suggest a facilitatory role of NO production in hypoxia/hypoglycemia-induced presynaptic dysfunction in CA1 regions of hippocampal slices.

Hepatic resection under in situ hemihepatic hypothermic perfusion with hepatoprotective agents

Hepatectomy was performed under in situ right lobar hypothermic perfusion combined with hepatoprotective agents in six patients who had hepatocellular carcinoma and coexisting liver disease. Following occlusion of the right hepatic vein and the right portal pedicle, in situ cold perfusion was initiated using chilled Ringer's lactate infused through a cannula placed in the right main portal vein. The right superior segments were resected in a bloodless field. The liver was cooled to 22-26 degrees C for 40 to 80 minutes with no significant changes in systemic hemodynamics or body temperature. Postoperative liver functions showed no marked derangement; the mean peak GPT was 221 U and the mean peak total bilirubin 2.3 mg d/l. Local cooling minimizes the risk of ischemia/reperfusion injury in this very vulnerable population, yet gives the surgeon adequate time to perform a challenging resection in a bloodless field.

Detection of immunoreactive antigen, with a monoclonal antibody to measles virus, in tissue from a patient with Crohn's disease

Using immunofluorescence (IF), we investigated reactive antigens present in Crohn's disease patients with monoclonal antibodies derived from cells infected with measles virus, but not with the subacute sclerosing panencephalitis virus. During immunoblotting, one monoclonal antibody (mAb 86) reacted with a polypeptide with a molecular weight of 36,000 dalton (M; matrix protein) in measles virus-infected cells. This monoclonal antibody displayed a positive reaction only with tissues from patients with Crohn's disease by the IF test. It did not react with samples from patients with other chronic inflammatory bowel diseases, such as ulcerative colitis. Other monoclonal antibodies to the measles virus protein, and monoclonal antibodies to Herpes simplex virus type 1 did not react with the same tissue samples. The role of measles virus infection and/or a viral antigen (possibly the M protein) as a causative agent in Crohn's disease poses a challenging avenue for further research.

IL-2 inhibits IL-4-dependent IgE and IgG1 production in vitro and in vivo

Nippostrongylus brasiliensis (Nb) infection of mice induces IL-4 producing CD4+ T cells which stimulate polyclonal IgE and IgG1 production, providing a model system to study IL-4 action on B cells in vivo. B cell Ia expression and the proportion of IL-2R beta positive B cells were increased in Nb-inoculated mice, and B cells from these mice responded to IL-2 by prompt and marked cell growth. Injection of anti-IL-4 1 day after Nb inoculation substantially inhibited these responses, indicating that they were largely IL-4 dependent. Thus IL-4 acted as a polyclonal B cell activator in vivo and caused B cells to develop into IL-2 responsive cells. Furthermore, injection of IL-2 inhibited IgG1 and IgE production by Nb-inoculated mice. To understand the mechanism of this IL-2-mediated inhibition, we used an in vitro IgG1 and IgE induction system. B cells from Nb-inoculated mice displayed an increase in the capacity of IL-2 to inhibit lipopolysaccharide (LPS) plus IL-4-driven IgE and IgG1 production, indicating that B cells expressing IL-2R beta are highly sensitive to IL-2. This inhibition was principally dependent upon the direct action of IL-2 on B cells. However, partial abolition of IL-2 inhibitory action by anti-IFN-gamma treatment suggested that endogenous IFN-gamma released from IL-2-stimulated cells was also involved in this IL-2-mediated IgE and IgG1 inhibition. Northern blot analysis demonstrated that IL-2 inhibited IL-4 induction of germline and productive C epsilon transcripts in LPS-stimulated B cells. Digestion-circularization polymerase chain reaction analysis revealed IL-2 inhibited IL-4 induction of s mu-s gamma 1 rearrangement in LPS-stimulated B cells.

[Intra-and extracranial chondrosarcoma]

A 17-year-old female, who had diplopia and progressive gait disturbance, had been diagnosed as having a right parasellar mass lesion in 1986. Initial CT scan failed to show a parasellar space occupying lesion, although it was well demonstrated on MRI. No surgery was carried out at that time. Seven years later, she was hospitalized because of progressive gait disturbance, lower cranial nerves palsy, and cerebellar sign as well as the known right abducence palsy. At this time, CT scan exhibited a huge low density area with a marginal high density area suggesting calcification, which extended from the right parasellar area to the ventral portion of the midbrain. She underwent surgery under the diagnosis of cartilaginous tumor or chordoma. The intracranial lesion was removed via combined translabyrinthine approach and epidural subtemporal approach. The tumor was hitologically diagnosed as well-differentiated chondrosarcoma. Electron-microscopy demonstrated tumor cells with features of chondrocytes. Since the original site of the tumor, strategies for treatment and prognosis are different from each other, distinction between chondrosarcoma and chordoma is important. MRI seemed very useful for making this distinction as a first step.

Signaling through CD40 rescues IgE but not IgG or IgA secretion in X-linked immunodeficiency with hyper-IgM

The ligand for CD40 (CD40L) is a membrane protein on activated T cells that induces B cell proliferation and differentiation. Several mutations of the CD40L gene were reported responsible for defective class switching of B cells in an X-linked immunodeficiency with hyper IgM (X-HIM). We studied four affected males from three families and found three independent mutations including new mutations of CD40L gene. In every X-HIM patient tested, however, anti-CD40 plus IL-10 did not induce class switching from IgM to IgG or IgA, even in the presence of Staphylococcus aureus Cowan I strain (SAC). CD4+ T cell clones, expressing CD40L on their surface, also did not rescue IgG or IgA induction by X-HIM peripheral blood B cells in vitro. But signaling through CD40 induced both B cell proliferation and IgE secretion when IL-4 was added to the culture. Taken together, these results show that in vitro signaling through CD40 rescues IgE but not IgG or IgA secretion by peripheral blood X-HIM B cells and suggest that in vivo CD40 and CD40L interaction might be necessary for IgG and IgA differentiation in X-HIM.

Aquaretic effect of a potent, orally active, nonpeptide V2 antagonist in men

Solute-free water diuretics (aquaretics) that antagonize hydrosmotic vasopressin 2 (V2) receptors may be useful in treating diseases in which water is retained. An orally active, nonpeptide, selective V2 antagonist (OPC-31260) was administered in six dose steps (3, 15, 30, 60, 100 and 200 mg) to six healthy, normally hydrated men to investigate the aquaretic effects in comparison with 12 placebo-treated control subjects (two at each dose). All subjects tolerated all six doses without serious clinical side effects. OPC-31260 increased the first 6-hr hypotonic urine volume dose-dependently. Administration at 30 mg raised the 6-hr urine volume to 2 times, 100 mg to 3 times and 200 mg to 4 times (1828.0 +/- 130.2 ml/6 hr) that of the placebo group (470.4 +/- 52.1 ml/6 hr). The drug increased urine flow maximally between 1 and 1.5 hr at all doses (e.g., 10.0 +/- 0.7-10.8 +/- 0.4 ml/min at 60-200 mg). The drug rapidly lowered urine osmolality for 4 hr, particularly between 60 and 90 min (e.g., 72.3 +/- 2.3 and 62.3 +/- 5.1 mOsm/kg at 100 and 200 mg, respectively). In marked hypotonic diuresis, mean free-water clearance of the 6-hr urine increased dose-proportionally into the positive range, reaching 2.82 +/- 0.21 ml/min at 200 mg.(ABSTRACT TRUNCATED AT 250 WORDS)

[Lymphatics of the thoracic surface of the diaphragm especially located around the inferior surface of the pericardial sac]

The lymphatics on the thoracic surface of the diaphragm, especially lying around the lateral and posterior sides of the base of the cardiac sac, were examined in 68 adult Japanese cadavers macroscopically (37 males and 24 females, aged 45-92 years, no clinical evidences of neoplasms). In this observation, a vein which drained into the terminal portion of the inferior vena cava was observed. The lymph nodes in this region were located along the vein frequently (80.9%). The vein passed through the esophageal hiatus, or penetrated the diaphragm and finally communicated with veins around the esophagogastric junction. However, lymphatic vessels were not observed passing through the phrenico-esophageal membrane and/or the diaphragm. The collecting vessels, which originated from the lymphatics, drained into the esophageal lymphatics, and it drained into the thoracic duct via the esophageal lymphatics. In pleural effusion cases, lymphatic nets were clearly observed on the thoracic surface of the diaphragm immediately under the parietal pleura. The lymphatic nets did not communicate with the diaphragmatic lymphatics around the base of the cardiac sac. Moreover, large collecting vessel from the lymphatic nets passed through the muscular crus of the diaphragm near the medial arcuate ligament and traveled inferior to merge at the original portion of the thoracic duct at the level of the renal vessels. From these observations, the lymphatics on the posterior part of the thoracic surface of the diaphragm communicated with several regional lymphatics independently. This morphological lymphatic traveling suggests that the route differs in cases of pleural effusion or cancer metastasis.

Targeted disruption of the NF-IL6 gene discloses its essential role in bacteria killing and tumor cytotoxicity by macrophages

To investigate the role of NF-IL6 in vivo, we have generated NF-IL6 (-/-) mice by gene targeting. NF-IL6 (-/-) mice were highly susceptible to infection by Listeria monocytogenes. Electron microscopic observation revealed the escape of a larger number of pathogens from the phagosome to the cytoplasm in activated macrophages from NF-IL6 (-/-) mice. Furthermore, the tumor cytotoxicity of macrophages from NF-IL6 (-/-) mice was severely impaired. However, cytokines involved in macrophage activation, such as TNF and IFN gamma, were induced normally in NF-IL6 (-/-) mice. Nitric oxide (NO) formation was induced to a similar extent in macrophages from both wild-type and NF-IL6 (-/-) mice. These results demonstrate the crucial role of NF-IL6 in macrophage bactericidal and tumoricidal activities as well as the existence of a NO-independent mechanism of these activities. We also demonstrate that NF-IL6 is essential for the induction of G-CSF in macrophages and fibroblasts.

Protective effect of peptide leukotriene antagonist on renal failure induced by a tourniquet in rabbits

We studied the effects of a selective antagonist of peptide leukotriene D4/E4 (LY-171883) and 5-lipoxygenase inhibitor diethylcarbamazine (DEC) in renal failure induced by a tourniquet, because peptide leukotrienes (LTs) were suggested to play a key role in our previous study. The hind limbs of anesthetized rabbits were fastened for 5 h and then released for 6 h. LY171883 (4 mg/kg/h) and DEC (40 mg/kg/h) were administered via the aural vein from 30 min before the tourniquet and during the experiment in each tourniquet group. The tourniquet induced renal injuries represented by increases in serum BUN and creatinine, and the injuries in the fastened muscles represented increases in serum CPK and edema index of the fastened site. LY171883 and DEC significantly attenuated the aggravation of the renal functions induced by a tourniquet when compared with the vehicle-treated group. LY171883 did not affect the injuries in the fastened muscles, but DEC attenuated it significantly when compared with the vehicle-treated group. The protection of peptide LT antagonist and 5-lipoxygenase inhibitor in the tourniquet-induced renal failure elucidate that peptide LTs trigger renal failure induced by a tourniquet.

Structural and functional significance of cysteine residues of glutathione-independent prostaglandin D synthase. Identification of Cys65 as an essential thiol

Glutathione-independent prostaglandin D synthase in rat brain is composed of 189 amino acid residues and catalyzes the isomerization of prostaglandin H2 to prostaglandin D2, an endogenous sleep-promoting substance. This enzyme is the only enzyme among members of the lipocalin superfamily composed of various secretory lipophilic ligand-carrier proteins and is recently identified to be a beta-trace protein, a major constituent of human cerebrospinal fluid. We expressed the active enzyme in Escherichia coli and then systematically substituted all cysteine residues of the delta 1-29 enzyme at positions of 65, 89, and 186 with alanine or serine. The parent and mutant enzymes were purified to apparent homogeneity with a recovery of approximately 30% by chromatography with Sephadex G-50 and S-Sepharose, by which all the enzymes showed identical elution profiles. The purified enzymes, irrespective of the mutation, showed almost the same circular dichroism spectral characteristics as displayed by a highly ordered beta-structure. The recombinant enzymes containing Cys65 showed the activity comparable with that of the enzyme purified from rat brain (approximately 3 mumol/min/mg of protein) in the presence, but not in the absence, of sulfhydryl compounds. However, all of the single, double, and triple mutants without Cys65 lost the enzyme activity. The purified delta 1-29 Ala89,186 enzyme was inactivated reversibly by conjugation with glutathione at Cys65 and irreversibly by the stoichiometric chemical modification with N-ethylmaleimide. These results indicate that Cys65 is an essential thiol of the enzyme and that both the intrinsic and extrinsic sulfhydryl groups are necessary for nonoxidative rearrangement of 9,11-endoperoxide of prostaglandin H2 to produce prostaglandin D2 catalyzed by the enzyme.