Evidence that glucose metabolism is decreased in the cerebrum of aged female senescence-accelerated mouse; possible involvement of a low hexokinase activity

d-Glucose metabolism in cerebral cells prepared from aged senescence-accelerated mouse (SAM), was investigated in consideration of a sex difference. The production of 14CO2 from 6-[14C]D-glucose was reduced in female senescence-accelerated-prone mouse (SAMP) 8, a prone substrain, in comparison with that in female senescence-accelerated-resistant mouse (SAMR) 2, a control substrain, whereas there was no difference in males. The 2-deoxy-D-glucose uptake into cerebral cells from female SAMP8 was also lower than that of control mice. But, the 3-O-methyl-D-glucose uptake in SAMP8 was higher than that of SAMR2, suggesting that the low hexokinase activity was involved in the decreased glucose metabolism in cerebrum of SAMP8 females irrespective of glucose transporter. This possibility was supported by the finding that the contents of glucose 6-phosphate produced from glucose added to cerebral cells from SAMP8 was lower than that in ICR mice.

Molecular cloning of a RNA binding protein, S1-1

S1 proteins A-D constitute a nuclear protein family that are liberated rapidly in a set from chromatin by mild digestion with a DNA or RNA hydrolyzing enzyme. With an anti-S1-protein B antiserum that reacted with B2, C1 and D1, a cDNA clone, pS1-1, was obtained, which encoded a protein of 852 amino acids. The S1-1 protein, encoded within the cells by a mRNA of 3480 nt, was a novel protein and could be distinguished from the S1 proteins B, C and D by their amino acid sequences. The S-1-1 protein synthesized by in vitro translation bound to RNA homopolymers, with a preference for G and U polyribonucleotides and little for poly(A). The protein contained two tandem RNP motifs and several intriguing sequences, such as a novel repeat of five octamers with a consensus sequence DP-S(Q/G)YYY and a potentially perfect amphipathic alpha-helix of five turns with basic and acidic amino acids positioned in an ordered way. The two RNP motif sequences were similar, although homologies were low, to the RNP motif sequences of yeast NSR1 protein, animal nucleolins, Drosophila hnRNP Al and tobacco chloroplast RNP precursor protein, suggesting a functional uniqueness of the S1-1 protein in RNA metabolism and also the evolution of its RNP motif structure before plants and animals diverged. These results indicate that the S1-1 protein encoded by the cDNA is a new class of RNA binding protein.

[A study of soluble form of L-selectin in blood of patients with neuroimmunological disorders]

Members of the selection family mediate the first step of leukocyte-endothelial cell interaction in inflammatory lesion. We have examined the soluble form of L-selectin (sL-selectin) in patients with neuroimmunological disorders (48 multiple sclerosis, 2 Balo's sclerosis, 18 Guillain-Barré syndrome, 7 Miller-Fisher syndrome, 8 chronic inflammatory demyelinating polyneuropathy, and 25 human T-lymphotropic virus type-1 associated myelopathy). The levels of sL-selectin were measured by monoclonal antibody-based enzyme immunoassay on serum samples taken from patients with neuro immunological disorders. The level of sL-selectin were significantly decreased in the blood of patient with inactive stage of multiple sclerosis (MS), Guillain-Barré syndrome (GBS), and human T-lymphotropic virus type-1 associated myelopathy (HAM). The levels of sL-selectin in the sera of patients with active phase of MS tended to be high, but not significantly increased. The levels of sL-selectin, however, in the sort of patients with Balo's concentric sclerosis tended to be decreased. Thus, the findings that the serum concentrations of sL-selectin were decreased in stable phase of MS and acute phase of GBS and HAM suggest that sL-selectin may be differently involved in between patients with MS and patients with GBS or HAM.

5-HT3 receptor blocking properties of the antiparkinsonian agent, talipexole

1. Talipexole showed moderate displacement activity of 3H-GR 65630 binding to 5-HT3 receptors in both rat cortical and intestinal membrane fractions with Ki values of 0.35 microM and 0.22 microM, respectively. 2. Bromocriptine failed to displace the binding activity in either experimental system even at a concentration of 10 microM. 3. Both talipexole and tropisetron were found to significantly inhibit 5-HT3 receptor-mediated effects of 5-HT in isolated guinea-pig ileum or atrium; however, the effect of talipexole was weaker than that of tropisetron. 4. Bromocriptine, in contrast, had no antagonistic effects on 5-HT3 receptor-mediated activity in guinea-pig ileum or atrium. 5. It was concluded that talipexole might act as an antagonist on 5-HT3 receptors in both brain and intestinal tissues.

The level of tumor necrosis factor-alpha producing cells in the spinal cord correlates with the degree of Theiler's murine encephalomyelitis virus-induced demyelinating disease

The levels of tumor necrosis factor (TNF)-alpha producing cells were analyzed in mice with Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD). Using an ELISPOT assay, we demonstrate an increase in TNF-alpha producing cells in the spinal cords of TMEV-infected SJL/J mice, especially at an active disease stage. The numbers of TNF-alpha producing cells were extremely high in susceptible SJL/J mice compared with the numbers in resistant BALB/c and C57BL/6 mice. TNF-alpha producing cells were also immunohistochemically identified in active lesions of TMEV-IDD at acute as well as chronic stages. The percentage of TNF-alpha producing cells compared with the total number of cells isolated from spinal cords was higher in TMEV-infected SJL/J mice than resistant BALB/c and C57BL/6 mice. Correspondingly, the level of TNF-alpha was much higher in the culture supernatants of both infiltrating cells in the spinal cords and spleen cells from clinically affected animals than that from similarly treated resistant mice. Treatment of virus-infected mice with a mAb specific for TNF-alpha at the beginning of the onset of disease suppressed the development of the demyelinating disease. These findings suggest that TNF-alpha may play an important role in the pathogenicity of TMEV-IDD.

Structure of heads A and B of myosin studied by tryptic digestion of myosin subfragment-1

We studied the difference in the structure of head B (P1-burst head) and head A of myosin by limited tryptic digestion of myosin subfragment-1 (S-1), and using antibodies (anti-A and anti-B) which bind specifically with each head. The antibodies were prepared using peptides with sequences identical to those around the reactive lysine residue of heads A and B. When myosin subfragment-1 (S-1) was cleaved limitedly by trypsin, S-1 heavy chain (100 kDa) was digested into fragments of 25, 50, and 20 kDa. Two fragments with molecular masses of 75 and 27 kDa were transiently produced in the initial phase of digestion. Anti-A and anti-B antibodies bound only with peptides that contained the reactive lysine residue [S-1 heavy chain (100 kDa), 75-, 27-, and 25-kDa peptides], thus showing specific binding with antigen peptide. However, the 27-kDa fragment bound more strongly with anti-B antibody than with anti-A antibody. When S-1 was separated into fractions rich in S-1A and S-1B using insoluble anti-A or anti-B antibody, each antibody bound more strongly with the S-1 heavy chain (100 kDa) of its corresponding fraction by Western immunoblotting. These results suggest that the antibodies react specifically with peptides even after SDS-PAGE and membrane-blotting, and that the structure of the 25 kDa 50 kDa junction differs between heads A and B of myosin.

[How to determine the best combination assay by several tumor markers?]

Combination assay by several tumor markers provides more precise diagnosis of malignancy than using a single tumor marker. The best combination assay by two tumor markers is determined as follows. MINIMIZE RFP (1-SpAorB(CA, CB)) + RFN(1-SnAorB(CA, CB)), where RFP, RFN denote the loss of false positive and false negative, respectively. SpAorB (CA, CB), SnAorB (CA, CB) are specificity and sensitivity of the combination assay by tumor markers A, B with cut-off values CA, CB.

[A case report of surgical treatment for acute mitral insufficiency associated with acute gastric lesion]

A 76-year-old female was admitted to our hospital due to anterior chest pain and dyspnea. Mitral regurgitation due to prolapse of the posterior leaflet was detected by UCG. After admission, massive gastric hemorrhage was observed. Because hemostatic therapy using endoscopy was not effective, partial gastrectomy was performed. The origin of the hemorrhage, an acute gastric ulcer, was located on the side of the minor curvature of the corpus ventriculi. After gastrectomy, the patient underwent medical treatment using an IABP, but the left heart failure was not reduced, and the pulmonary edema worsened. At 18 hours after gastrectomy, MVR was performed. The cause of regurgitation is torn chordae of the posterior leaflet. The postoperative course was good, and the patient is doing well in NYHA class 1. This case is the first report of acute mitral insufficiency associated with acute gastric lesion in Japan.

Inhibition of proliferation of chondrocytes by specific receptors in response to retinoids

All-trans retinoic acid inhibited the proliferation of chondrocytes derived from rat xiphoid cartilage when added to the culture medium at 10(-10)-10(-8) M. Proliferation of mouse clonal osteoblastic cells was also inhibited to a significant extent by all-trans retinoic acid. However, no such inhibitory effects on rat smooth muscle cells and human fibroblasts were observed. Flow cytometric analyses of chondrocytes labeled with propidium iodide revealed that all-trans retinoic acid arrested chondrocytes at the G1 phase of the cell cycle. Since 9-cis retinoic acid, which is synthesized enzymatically from all-trans retinoic acid, also inhibited the proliferation of chondrocytes, we investigated the subtypes of retinoic acid receptors in chondrocytes. Northern blot analysis revealed high levels of mRNA for retinoid X receptor alpha (RXR alpha), moderate levels of mRNA for retinoic acid receptor gamma (RAR gamma), and low levels of mRNA for RAR alpha and RXR beta. The mRNA for RAR beta and RXR gamma were not detected. These results suggest that retinoids are associated with the inhibition of proliferation of chondrocytes via both families of nuclear receptors, namely, RARs and RXRs.

Chylopericardium following right thoracotomy for lung cancer

A 69-year-old woman underwent the right upper lobectomy, a partial resection of right segment 6 (rt S6) and removal of mediastinal lymph nodes (LN) for adenocarcinoma of the lung (rt S2), stage IIIA (T2N2M0). A chest computerized tomography (CT) taken one month after the operation revealed a pericardial effusion which was milky in color, and contained high levels of triglycerides (TG) of 615 mg/dl (serum, 217 mg/dl). Cytology of effusion for malignant cells was negative. The pericardial effusion gradually decreased in one month by restriction of her fat intake. Chylopericardium following right thoracotomy for lung cancer is extremely rare.

cGMP produced in response to ANP and CNP regulates proliferation and differentiation of osteoblastic cells

The effects of natriuretic peptides on the proliferation and differentiation of osteoblast-like cells from rat calvariae were examined. Natriuretic peptides are physiological agonists that activate receptor guanylate cyclases, namely, natriuretic peptide receptor (NPR)-A and NPR-B. Exposure of cells to atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) resulted in large increases in the rate of intracellular production of guanosine 3',5'-cyclic monophosphate (cGMP). Moreover, CNP-like immunoreactivity was detected in the conditioned medium from osteoblast-like cells, while ANP was undetectable. In cells exposed to natriuretic peptides, a dose-dependent reduction in the rate of DNA synthesis was observed. Natriuretic peptides also stimulated the activity of alkaline phosphatase (ALPase) and the expression of mRNA for ALPase and osteocalcin and the mineralization of nodules by the cultured cells. These results could be reproduced by treating cells with 8-bromo-cGMP. Endothelin-1, whose physiological functions are the opposite of those of natriuretic peptides, decreased the ALPase activity and the mineralization of nodules. In the present study, natriuretic peptides were demonstrated to promote bone formation via the action of cGMP in a signal-transduction pathway mediated by specific receptors in osteoblast-like cells.

Stimulation by C-type natriuretic peptide of the differentiation of clonal osteoblastic MC3T3-E1 cells

We examined the effects of C-type natriuretic peptide (CNP) and B-type natriuretic peptide receptor (NPR-B) system, which stimulates the intracellular production of cGMP, on osteoblastic differentiation using clonal murine calvarial MC3T3-E1 cells. CNP-like immunoreactivity was detected in the conditioned medium and in lysates of MC3T3-E1 cells. Exposure of cells to CNP caused an increase in the intracellular production of cGMP and the increase was dose-dependent, while ANP had no effect. These results imply that CNP regulates osteoblastic metabolism via NPR-B in an autocrine manner. Northern blot analysis revealed that treatment of MC3T3-E1 cells with CNP increased the steady-state levels of mRNAs for type-I collagen, cellular alkaline phosphatase (ALPase), and osteocalcin, which are well known as markers of osteoblastic differentiation. Our observations suggest the possibility that CNP functions as a local regulator of osteoblastic differentiation, acting via a cGMP-mediated pathway.

Cloning, sequencing and transcriptional regulation of the draT and draG genes of Azospirillum lipoferum FS

From Azospirillum lipoferum (Al) FS, a nitrogen-fixing bacterium isolated from the rhizosphere of rice, we cloned and sequenced draT, encoding dinitrogenase reductase ADP-ribosyltransferase, and draG, encoding dinitrogenase reductase-activating glycohydrolase. The nucleotide sequences of draTG showed extensive similarity to the same genes from Azospirillum brasilense, Rhodospirillum rubrum and Rhodobacter capsulatus, and they are assumed to be co-transcribed as a single operon. When this draTG operon was introduced into Klebsiella oxytoca, this organism acquired the ability to respond to extracellular NH(+4) ions with reversible inhibition of nitrogenase activity, similar to that seen in Al FS. We constructed a plasmid containing a draT::lacZ gene fusion and found that beta-galactosidase activity was detected under microaerobic conditions, regardless of NH(+4) concentration, but not under aerobic conditions. This indicates that the transcription of draTG responds to the level of oxygen, but not to that of NH(+4) ions.

[A study on the pathogenesis of hepatomegaly in patients with Crow-Fukase syndrome]

We studied pathogenesis of hepatomegaly in Crow-Fukase syndrome. Hepatocytes were isolated from BALB/c mice and cultured with serum or ascites of three patients with Crow-Fukase syndrome. After 24 hours culture, total number of hepatocytes was counted. The levels of human hepatocyte growth factor (h-HGF) in the serum were also measured. In the hepatocyte culture study, the numbers of hepatocytes after 24 hours cultured in the serum of two patients were significantly larger than those of the control group. When the hepatocytes were cultured with patients' serum after corticosteroid therapy, the survival numbers were markedly reduced. The serum levels of h-HGF in our three patients were 0.62, 0.52, 0.53 ng/ml respectively. They were all slightly higher than normal values (< or = 0.39 ng/ml). Our study indicates that in the serum or ascites of patients with Crow-Fukase syndrome, there may be some humoral factors other than h-HGF, which promote proliferation of hepatocyte or protect hepatocyte.

Cervical myelopathy in elderly patients: clinical results and MRI findings before and after decompression surgery

We examined 173 patients with cervical myelopathy of various causes. Seventy-seven patients underwent anterior decompression and fusion at not more than two levels, while 96 underwent posterior decompression by an expansive laminoplasty. Patients were followed up for between one and 4 1/2 years and the outcome was assessed both from a functional and a radiological point of view. The functional assessment used was according to the Japanese Orthopaedic Association (JOA) score (the higher the better), and the imaging outcome was assessed by a midline sagittal MRI assigned to three categories either for restoration of cord morphology, improvement or unchanged. Patients were divided into two groups: those 65 years old and older (50 patients), and those younger than 65 years old (123 patients). The data allowed the following conclusions to be reached: Older patients were likely to have more levels, and higher levels affected, and as a result were more likely to require a posterior operation. The recovery rate after an anterior operation was the same as that after a posterior operation. The pre- and post-operative JOA scores were higher in younger patients who tended to have milder disease with fewer levels affected. Younger patients had better morphological restoration. The recovery was likely to be better if the postoperative morphology was better. The morphology postoperatively was likely to be better if there had been less compression preoperatively. If the morphology was restored the disease duration was likely to have been less. The patients did better if the cord morphology was restored to normal, and this was easier to achieve in younger patients who had fewer levels involved and had less cord distortion preoperatively.

Binding affinity of sarpogrelate, a new antiplatelet agent, and its metabolite for serotonin receptor subtypes

We analyzed the displacement activity of sarpogrelate and its active metabolite (M-1) in the radiolabeled ligand binding to various 5-hydroxytryptamine (5-HT) receptor subtypes using rat brain cortical membranes. Sarpogrelate was shown to have the same affinity as ritanserin for 5-HT2A receptors, with a Ki value of 8.39 nM. The active metabolite of sarpogrelate, M-1, was more active than sarpogrelate itself and of ritanserin, with a Ki value of 1.70 nM. Both sarpogrelate and M-1 had no affinity for 5-HT1A receptors, but these substances, at a concentration of 10 microM, displaced the specific binding to the 5-HT1B receptors of [125I]iodocyanopindolol, resulting in Ki values of 0.881 and 0.859 microM, respectively. The Ki values of sarpogrelate and M-1 are almost the same as that of ritanserin, a specific 5-HT2 receptor antagonist. Sarpogrelate and M-1, as well as ritanserin, are shown to have very low affinity for 5-HT1B receptors. Both sarpogrelate and M-1 had no affinity for 5-HT3 receptor subtypes. In the 5-HT4 receptor binding experiments, sarpogrelate exhibited almost no affinity, while M-1, at the concentration of 10 microM, displaced the binding activity, resulting in a Ki value of 0.838 microM. Both drugs had a weak antagonistic effect on a 5-HT4 receptor-mediated function, i.e., the 5-HT-induced relaxation of rat isolated esophageal tunica muscularis mucosae. In conclusion, sarpogrelate and M-1 have high affinity for 5-HT2A receptors with a relatively high selectivity.

Production of IL-6 by T cells from the femoral head of patients with rapidly destructive coxopathy (RDC)

RDC is a syndrome with unknown etiology that causes rapid destruction of a hip joint. We have investigated the production of osteoclast-activating cytokines (IL-6, IL-1alpha and tumour necrosis factor-alpha (TNF-alpha)), interferon-gamma (IFN-gamma) and IL-8 by T cells in the affected joint. The level of IL-6 produced by the T cell lines (TCL) established from the femoral head was significantly higher than that from patients' or healthy donors' peripheral blood mononuclear cells (PBMC). IL-6 production by the TCL from synovial membrane or from patients' PBMC was also significantly higher than that from healthy donors' PBMC. IL-1alpha production by the TCL from the femoral head was significantly higher than any of the other groups when all the TCL were used for the analysis. TNF-alpha production was highest in the TCL from patients' PBMC. The levels of IFN-gamma or IL-8 were not significantly different among these four groups. The plasma levels of all these cytokines except for IFN-gamma, that was rather lower, in RDC patients were not significantly different from those in osteoarthrosis or trauma patients, or healthy donors. These results suggest that T cells at the affected femoral head, and also synovial membrane to some extent, are involved in bone resorption through the production of IL-6 and probably IL-1alpha in patients with RDC.

Flushing pattern and idiopathic avascular necrosis of the femoral head

A cooperative hospital-based case-control study of idiopathic avascular necrosis of the femoral head (IANF) was carried out to clarify the involvement of smoking, drinking, flushing pattern, and other factors in the development of IANF comparing 90 cases (64 males and 26 females) without history of systemic corticosteroid use with 180 matched controls (128 males and 52 females). The results of analyses were represented only for male subjects because of small number of female cases. There was no significant difference in smoking habits, daily and cumulative number of cigarettes smoked between case and control groups. Current drinkers had obviously higher risk (OR = 11.47) of IANF compared to nondrinkers or exdrinkers. In addition, there was a consistent risk increase with increasing alcohol consumption and the highly significant dose-response relationship remained unchanged after adjustment for all other factors (chi 2 = 14.33, p < 0.001 and chi 2 = 13.24, p < 0.001 for daily and cumulative alcohol consumption, respectively). For flushing pattern, although nonflushers had a significantly elevated risk (OR = 2.08) in the univariate analysis, the association disappeared (OR = 0.73) after adjustment for alcohol and other factors. Since nonflushers tend to be heavy drinkers, perhaps, an apparent risk increase among nonflushers may be due to alcohol drinking. Body mass index (BMI) was inversely related to the development of IANF. The risk reduction was found among subjects with higher BMI and an adjusted linear trend of OR was significant (chi 2 = 6.65, p < 0.05). However, further studies were required regarding the association between flushing pattern or BMI and IANF because of a few reports. History of liver diseases and occupational history were not significantly associated with the development of IANF after adjustment for other factors.

Change in the expression of C-type natriuretic peptide and its receptor, B-type natriuretic peptide receptor, during dedifferentiation of chondrocytes into fibroblast-like cells

Chondrocytes derived from rat xiphoid cartilage dedifferentiated into fibroblast-like cells as the number of passages of the cells in culture increased. During in vitro dedifferentiation the growth of the cells was markedly suppressed. We had proposed previously that C-type natriuretic peptide (CNP) might be a potent antimitogenic factor for chondrocytes, and TGF-beta 1 induced a marked increase in CNP secretion of chondrocytes. Therefore, we investigated the expression of CNP, B-type natriuretic peptide receptor (NPR-B or GC-B), and TGF-beta 1 in this process. Radioimmunoassay and RNase protection analyses revealed passage-associated increase in CNP-like immunoreactivity and in levels of NPR-B mRNA, respectively. Northern blot analyses showed that the level of TGF-beta 1 mRNA decreased with increasing passage number. These results suggest that the expression of CNP and NPR-B might be involved in in vitro dedifferentiation of chondrocytes and TGF-beta 1 does not affect the increasing level of CNP during in vitro dedifferentiation.

Competitive polymerase chain reaction for the quantification of N-myc gene copy number in neuroblastoma

An absolute quantification method for the N-myc gene copy number of neuroblastoma specimens was established by applying the competitive polymerase chain reaction (cPCR). The competitor plasmid (pZH2) lacking an MluI site in the exon 2 was constructed to distinguish two product species amplified from genomic DNA and the competitor plasmid. By using this cPCR system, we could obtain qualitative results within 1 day, i.e. amplified or unamplified, and quantitative results by using radiolabelled nucleotides within 4 days. The copy numbers of N-myc in 47 neuroblastoma specimens by cPCR correlated well with those by Southern hybridization (r = 0.85). We conclude that cPCR is a simple and rapid method, requires only a small amount (200 ng) of sample DNA, and is expected to be used for prognostic evaluation in neuroblastomas.

Isolating and characterizing deep-sea marine microorganisms

We have isolated several microorganisms that are adapted to living in the extremes of the deep-sea environment. They include barophilic bacteria, which are able to grow at high hydrostatic pressure, but that are unable to grow at atmospheric pressure, and organic-solvent-tolerant bacteria, which are able to grow in the presence of toxic organic solvents such as toluene or benzene. In this review, we describe how to isolate such extremophiles, and we outline the characteristics of several strains that have been recovered from the deep-sea environment.