Complete sequence of the Bacteroides fragilis YCH46 neuraminidase-encoding gene

The nucleotide sequence of the Bacteroides fragilis neuraminidase-encoding gene (nanH) and its flanking regions was determined. The B. fragilis nanH open reading frame (ORF) of 1632 nucleotides encoded a neuroaminidase of 544 amino acid residues with a calculated molecular mass of 59.51 kDa. The amino acid sequence at the N-terminus of the deduced protein exhibited the common features of procaryotic signal sequences. The Asp box sequence, Ser-X-Asp-X-Gly-X-Thr-Trp, which is conserved among bacterial neuraminidases, was found at five positions in the deduced amino acid sequence. A single transcription start point was identified 88 nucleotides upstream of the nanH ORF. Northern blot analysis using an internal nanH probe revealed a single mRNA species with a length of 1.8 kb that could encode just the neuraminidase.

Identification of DNA topoisomerases involved in immediate and transient DNA relaxation induced by heat shock in Escherichia coli

The linking number of plasmid DNA in exponentially growing Escherichia coli increases immediately and transiently after heat shock. The purpose of this study was to search for DNA topoisomerases that catalyze this relaxation of DNA. Neither introduction of a topA deletion mutation nor treatment of cells with DNA gyrase inhibitors affected the DNA relaxation induced by heat shock. Thus, DNA topoisomerase I and DNA gyrase are apparently not involved in the process. However, the reaction was inhibited by nalidixic acid or by oxolinic acid in the topA mutant and the reaction was resistant to nalidixic acid in a topA mutant carrying, in addition, the nalA26 mutation. These results are interpreted as indicating that both DNA topoisomerase I and DNA gyrase are involved in the DNA relaxation induced by heat shock.

Remote subarachnoid haemorrhage in the posterior fossa following supratentorial surgery. Clinical observation of 6 cases

Haemorrhage in regions remote from the site of following intracranial operations is rare, but they do occur. We performed supratentorial craniotomy on 639 patients between the time of introduction of computed tomography (CT) for clinical use in 1983 and June 1992; subarachnoid haemorrhage (SAH) in the posterior fossa occurred postoperatively in six of these cases. These included four patients with tumours in the sellar region, one with an arteriovenous malformation (AVM) and one who underwent superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis. The ages of the six patients ranged from 17-72 years. Haemorrhage occurred on the day of operation in one case and was detected on CT examination on the day following surgery in the remaining five cases. Of three patients with disturbance of consciousness, two underwent suboccipital craniectomy for reduction of intracranial pressure, while one received barbiturate therapy and later underwent cerebrospinal fluid (CSF) shunt surgery. No special treatment was necessary for the remaining three patients with less serious lesions. Five of the six patients ultimately recovered their pre-operative neurological status apart from the primary diseases. Factors inducing such haemorrhages seem likely to include displacement of the cerebellum by reduced CSF pressure during and after operations, and stretching and tearing of the veins and venules in the sulci of the tentorial surface of the cerebellum. Consideration should therefore be given to the maintenance of an appropriate CSF pressure during operation; this is particularly important in elderly patients and those with an atrophied cerebral cortex.

Uptake of transmitter amino acids by glial plasmalemmal vesicles from different regions of rat central nervous system

From rat hippocampal homogenate, we recently isolated a novel subcellular fraction richly containing glial plasmalemmal vesicles (GPV), which takes up glutamate remarkably as a synaptosomal fraction [Y. Nakamura et al. (1993) Glia, 9, 48-56]. In the present study, we prepared GPV from different regions of rat CNS, namely olfactory bulb (Ob), cerebral cortex (Cx), caudatoputamen (Cp), hippocampus (Hp), cerebellum (Ce) and spinal cord (Sc), and analyzed their activities of Na(+)-dependent uptake of following neurotransmitters and a related compound; glutamate, gamma-aminobutyrate (GABA), glycine, dopamine and choline. The uptake activities of these amino acids were not significantly different between GPV and synaptosomes in each region. Regionally, however, the activities were varied considerably. The activities of glutamate uptake revealed in the following rank order: Cx, Hp, Cp > Ce, Ob > Sc. GABA uptake activities were: Ce > Ob, Cx, Hp > Cp, while glycine uptake activities were: Sc, Ce > Ob, Cp, Cx, Hp. On the other hand, the uptake activities of dopamine and choline were quite different between GPV and synaptosomes. Synaptosomal fraction from Cp took up dopamine in a high activity; however, GPV from the same tissue hardly showed the uptake activity. Choline was taken up by synaptosomes prepared from Hp but not by GPV.

A marked increase in intracellular Ca2+ concentration induced by acromelic acid in cultured rat spinal neurons

Acromelic acid, a kainate derivative of natural origin, markedly increased intracellular Ca2+ concentration ([Ca2+]i) in cultured rat spinal neurons in a concentration dependent manner; the half effective concentration (EC50) was 1.3 microM. Acromelic acid was more potent in increasing [Ca2+]i than any other glutamate receptor agonists tested, and the rank order of the activity was as follows: acromelic acid > alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) > kainate > N-methyl-D-aspartate (NMDA) > L-glutamate. Acromelic acid did not increase the [Ca2+]i in a Ca(2+-)free medium. 2,3-Dihydroxy-9-nitro-7-sulfamoylbenzo(F)quinoxaline (NBQX) completely inhibited the [Ca2+]i increase induced by acromelic acid. These results suggest that the [Ca2+]i increase was not through Ca2+ mobilization from intracellular stores but due to Ca2+ influx mediated by the activation of non-NMDA receptors. Acromelic acid increased the [Ca2+]i in rat hippocampal neurons as well; however, the EC50 (6 microM) was considerably higher than that in spinal neurons. The marked increase of [Ca2+]i in cultured spinal neurons would explain, at least in part, the earlier findings that systemic administration of acromelic acid causes selective degeneration confined to lower spinal interneurons.

Cloning and expression of the Bacteroides fragilis YCH46 neuraminidase gene in Escherichia coli and Bacteroides uniformis

A neuraminidase-encoding gene nanH of Bacteroides fragilis strain YCH46 was cloned into the cosmid vector pHC79. The nanH gene was subcloned from the cosmid and was located within a 2.2-kb XhoI-KpnI fragment. Southern hybridization experiments demonstrated that the gene was present as a single copy on the bacterial chromosome. Neuraminidase activity expressed in the initial Escherichia coli clone was approximately 3600-fold lower than that expressed in B. fragilis YCH46. However, when nanH was transferred from E. coli to B. uniformis by mobilization of a shuttle plasmid, the transconjugant expressed 1100-fold higher activity than the E. coli donor did. These results suggest that modes of nanH expression in E. coli and Bacteroides are heterologous.

A novel metabotropic glutamate receptor agonist: (2S,1'S,2'R,3'R)-2-(2-carboxy-3-methoxymethylcyclopropyl)glycine (cis-MCG-I)

A novel agonist for metabotropic glutamate receptors, (2S,1'S,2'R,3'R)-2-(2-carboxy-3-methoxymethylcyclopropyl)glycine (cis-MCG-I), effectively inhibited monosynaptic excitation in newborn rat spinal cords with EC50 of 3 microM without causing any depolarization. Furthermore, cis-MCG-I inhibited the forskolin-stimulated cyclic AMP formation in rat cultured cortical cells with IC50 of 1.5 microM. cis-MCG-I neither stimulated the phosphoinositide hydrolysis nor activated ionotropic glutamate receptors even in high concentrations. However, after a brief exposure of spinal cords to quisqualate, it caused depolarization in a dose-dependent manner. This compound would provide useful information for elucidating physiological functions of metabotropic glutamate receptors.

[Three cases of arteriovenous malformation of the lung]

Three cases of arteriovenous malformation (AVM) of the lung are presented. The first patient was 36-year-old female and the second was 25-year-old male, and both with asymptomatic bilateral multiple small AVMs. We used coil spring occlusion in therapeutic transcatheter embolization of the AVMs. A pulmonary arteriogram confirmed the completely occluded AVMs. The another patient was 21-year-old female whose lips and nails were cyanotic. She had clubbing fingers and vascular murmur was audible on her chest wall. The laboratory examination revealed polycythemia and hypoxemia. A pulmonary angiogram revealed a single large AVM which was composed of a feeding artery (A9) and a draining vein (dilated basal pulmonary vein). We performed a left basal segmentectomy and postoperative course was uneventful. Transcatheter embolization is useful for the case of multiple or peripheral or small AVM of the lung, but the case of large solitary AVM with rapid blood flow is thought to be an indication for the operation. These two therapeutic modality should be selected case by case.

The efficiency of solvent extraction of mutagenic compounds in particulates exhausted from a small diesel engine

Organic materials were extracted from particulates exhausted from a small diesel engine (displacement 269 ml) by the ultrasonic extraction method with three different solvent systems, methanol, dichloromethane and a 4:1 (v:v) mixture of benzene and ethanol. These solvent-extracted materials were tested for mutagenic activity by the Ames Salmonella/microsome assay system using Salmonella typhimurium strains TA98, TA100, TA98NR and TA98/1,8-DNP6. The concentrations of 1-nitropyrene (1-NP) and 1,6-dinitropyrene (1,6-diNP) in these extracted materials were also measured after nitroreduction by high pressure liquid chromatography. The methanol-extracted and benzene-ethanol-extracted materials showed the lowest and the highest mutagenic activity, respectively. The methanol-extracted, dichloromethane-extracted and benzene-ethanol-extracted materials induced 260, 1,570 and 3,240 His+ revertants per plate per mg of extracted materials, respectively, from strain TA98 in the absence of S9 mix. These materials showed decreased mutagenicity for strains TA98NR and TA98/1,8-DNP6, indicating that the particulates in the diesel engine exhaust contained 1-NP and diNPs. Actually, the amount of 1-NP and 1,6-diNP in the methanol-extracted, dichloromethane-extracted and benzene-ethanol-extracted materials were 17.0 and 0.03 ng, 37.5 and 0.97 ng, and 71.3 and 1.03 ng per mg of extracted materials, respectively, accounting for 11.9 and 3.2%, 4.4 and 17.3%, and 4.0 and 8.9%, respectively, of the total mutagenicity of the extracted materials. From these results it is concluded that a mixture of benzene-ethanol (4:1, v/v) is the most suitable solvent for extraction of organic matter containing nitrated polycyclic aromatic hydrocarbons such as NPs from particulates in diesel engine exhaust.

The purification, characterization, cloning and sequencing of the gene for a halostable and thermostable leucine dehydrogenase from Thermoactinomyces intermedius

Leucine dehydrogenase has been purified to homogeneity from a moderate thermophilic actinomycete, Thermoactinomyces intermedius IFO 14230. The enzyme can be stored without loss of its activity at a low temperature (e.g., 4 degrees C) for over two years. The enzyme was more thermostable at higher concentrations of salts such as NaCl and KCl. It retained about 90% of activity on incubation at 70 degrees C for at least 40 min in the presence of 3 M NaCl. The Michaelis constants for NAD, L-leucine, NADH, 2-oxoisocaproate and ammonia were determined to be 0.36, 2.0, 0.042, 0.63 and 118 mM, respectively, from initial-velocity analyses. The enzyme showed pro-S stereospecificity for hydrogen transfer of NADH in the reductive amination. The enzyme gene was cloned into Escherichia coli and its complete DNA sequence was determined. The leucine dehydrogenase gene (leudh) consists of a 1098-bp open reading frame and encodes 366 amino acid residues corresponding to a subunit (M(r) 40586) of the octameric enzyme. The amino acid sequence of the enzyme showed 80.7% similarity with that of the Bacillus stearothermophilus enzyme. The enzyme was overproduced in E. coli JM 109 having a recombinant plasmid, pULDH2, which was constructed from pUC18 and the leudh gene. The enzyme was purified from the cell extract to homogeneity in one day, with 78% recovery.

[A case report of mitral valve replacement for infective endocarditis in pregnancy]

Infective endocarditis in pregnancy is uncommon. A 37-week pregnant woman presented with infective endocarditis. Echocardiography revealed prominent mitral valve vegetations. The patient underwent cesarean section and a 2,800 g male infant was delivered. In order to prevent embolization, mitral valve replacement was performed 3 days after cesarean section with SJM valve. Both mother and child are doing well now.

In vivo augmentation of the intratumoral concentration of 5-fluorouracil by cepharanthine--a biscoclaurine alkaloid

We have investigated the interaction between Cepharanthine (CEP), a multi-functional alkaloid that has the capacity to stabilize the cell membrane, and 5-fluorouracil (5-FU) against a human colon cancer cell line (RPMI 4788) transplanted into nude mice. Their anti-tumor effects were assessed in a group of 7 mice intravenously injected with CEP (5 mg/kg/day) and/or 5-FU (15 mg/kg/day) during a 3-week treatment. The results were compared with a control and a 5-FU group, which received saline solution and 5-FU alone, respectively. The tumors were harvested 2 h after 5-FU administration. On an additional 4 groups of 5 mice, the intratumoral concentration of 5-FU was assessed by a high performance liquid chromatographic (HPLC) method 2, 4, 6 and 12 h following CEP (5 mg/kg) injection 1 h prior to, simultaneously, and 1 h after injection of 5-FU (30 mg/kg). The mean (SD) intratumoral concentration of 5-FU was 0.16 (0.05) mu g/g, 0.32 (0.19) mu g/g, 0.32 (0.16) mu g/g and 0.21 (0.13) mu g/g in the control and the three other groups treated with CEP, respectively. This concentration was about twice as high in mice simultaneously treated with CEP compared to those treated by 5-FU alone. Relatively higher concentrations of 5-FU were noted up to 4 h following 5-FU injection in mice treated with CEP than in those injected only with 5-FU. CEP also enhanced the inhibitory effects of the 5-FU on tumor growth rate.(ABSTRACT TRUNCATED AT 250 WORDS)

[Long survival after removal of a huge brain tumor which had metastasized from a lung cancer: case report]

Patients with large metastatic brain tumors are considered to have poor prognosis. We report a case of a patient with more than 33 months survival after complete resection of a huge temporal tumor which had metastasized from a lung cancer. A 57-year-old woman presented left hemiparesis and disturbance of consciousness. Magnetic resonance images revealed a huge cystic mass lesion in the right temporal lobe. After a macroscopically complete excision of the tumor, she received radiation therapy (whole brain 50 Gray). She had received lung surgery for the primary lung cancer, 2 years prior to brain metastasis. Histological examination showed papillary tubular adenocarcinoma which was similar to the previously resected lung cancer. Thirty three months after the resection of the intracranial tumor, she has no neurological deficits and no signs of recurrence of either brain tumor or lung tumor. We discuss the size of metastatic brain tumor and the postoperative prognosis of patients with metastatic brain tumor.

Adenosine enhances intracellular Ca2+ mobilization in conjunction with metabotropic glutamate receptor activation by t-ACPD in cultured hippocampal astrocytes

2Cl-Adenosine, a non-metabolized adenosine agonist, enhanced the increase in intracellular Ca2+ concentration ([Ca2+]i) in cultured hippocampal astrocytes induced by (+-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (t-ACPD), a metabotropic glutamate agonist. In the absence of 2Cl-adenosine, the half effective concentration (EC50) of t-ACPD was about 80 microM. On the other hand, in the presence of 1 microM 2Cl-adenosine, the EC50 of t-ACPD shifted to about 5 microM, although the maximum [Ca2+]i did not change. The synergistic effect of 2Cl-adenosine with t-ACPD on [Ca2+]i elevation was not inhibited by the elimination of extracellular Ca2+, but was inhibited by A1-specific adenosine antagonists. These results indicate that adenosine can act via the A1 receptor as an endogenous co-activator of the metabolic processes induced by metabotropic glutamate receptor activation.

Regulation of transcription by dimerization of erythroid factor NF-E2 p45 with small Maf proteins

Transcription factor NF-E2 is crucial for regulating erythroid-specific gene expression. Cloning of the NF-E2 p45 protein has revealed that it contains a basic region-leucine zipper (b-zip) domain which associates with another unidentified protein (of relative molecular mass 18,000) to form functional NF-E2. We show here that products of the maf proto-oncogene family, MafF, MafG and MafK (the small Maf proteins) which possess a b-zip DNA-binding domain but lack a canonical transactivation domain, directly control the DNA-binding properties of p45 by heterodimeric association with p45. Whereas homodimers of the small Maf proteins act as negative regulators, heterodimers composed of Maf and p45 support active transcription in vivo. These results indicate that one (or all) of the small Maf proteins is the second constituent chain required for NF-E2 activity, and that negative as well as positive regulation can be achieved through an NF-E2 site, depending on the equilibrium concentrations of p45 and the Maf proteins inside erythroid cells.

Regulation of transcription by dimerization of erythroid factor NF-E2 p45 with small Maf proteins

Transcription factor NF-E2 is crucial for regulating erythroid-specific gene expression. Cloning of the NF-E2 p45 protein has revealed that it contains a basic region-leucine zipper (b-zip) domain which associates with another unidentified protein (of relative molecular mass 18,000) to form functional NF-E2. We show here that products of the maf proto-oncogene family, MafF, MafG and MafK (the small Maf proteins) which possess a b-zip DNA-binding domain but lack a canonical transactivation domain, directly control the DNA-binding properties of p45 by heterodimeric association with p45. Whereas homodimers of the small Maf proteins act as negative regulators, heterodimers composed of Maf and p45 support active transcription in vivo. These results indicate that one (or all) of the small Maf proteins is the second constituent chain required for NF-E2 activity, and that negative as well as positive regulation can be achieved through an NF-E2 site, depending on the equilibrium concentrations of p45 and the Maf proteins inside erythroid cells.

Changes in intracellular Ca2+ and energy levels during in vitro ischemia in the gerbil hippocampal slice

The time course of the decline in energy levels during an in vitro ischemia-like condition was compared with changes in intracellular Ca2+ concentration ([Ca2+]i) in subregions of the gerbil hippocampal slice [CA1, CA3, and the inner and outer portions of the dentate gyrus (DG)]. Hippocampal transverse slices were loaded with a fluorescent indicator, rhod-2. During the on-line monitoring of [Ca2+]i, the slices were perfused with an in vitro ischemia-like medium (33 degrees C). The slices were collected at several experimental time points, frozen, dried, and dissected into subregions. The contents of adenine nucleotides (ATP, ADP, and AMP) and phosphocreatine (PCr) were measured by HPLC methods. Region-specific and acute [Ca2+]i elevations were observed in CA1 approximately 4 min after onset of the in vitro ischemia-like condition and also in the inner portion of the DG with a delay of 10-40 s. The change in ATP levels was related to the increase in [Ca2+]i. ATP levels in all subregions gradually decreased before the acute [Ca2+]i elevation. Concomitant with the acute [Ca2+]i elevation in CA1 and the inner portion of the DG, ATP levels in the subregions rapidly decreased, whereas declines in levels of high-energy-charge phosphates were gradual in CA3 and the outer portion of the DG, in which the remarkable [Ca2+]i elevation was not observed. These results suggest that ATP depletion observed in CA1 and the inner portion of the DG is due to the region-specific increase in [Ca2+]i, which activates a Ca(2+)-ATP-driven pump and produces a subsequent fall in neuronal ATP content.

[Ureteral polyps: three case reports]

We observed recently three cases of ureteral polyps including a case of multiple polyps. The first patient was a 33-year-old man with multiple polyps at the left upper ureter. The second patient was a 51-year-old man and the third 49-year-old man, and both cases were complicated with ureteral stones. We divided 88 ureteral polyps reported in Japan from 1970 to 1990 into polyps in children and those in adults. We further divided the individual polyps into single and multiple polyps and examined them clinically. Characteristic findings were obtained in polyps in children; namely, multiple polyps were dominant, almost all of them occurred at the left upper ureter and no cases were complicated with ureteral stones. Furthermore, many of the multiple polyps in adults occurred at the left upper ureter and few were complicated with stones as in the children. In conclusion, the ureteral polyps in children and multiple ureteral polyps in adults were similar in character and we presumed that some congenital factors might be involved in their occurrence.

Preparation and characterization of a glucose-responsive insulin-releasing polymer device

A new glucose-responsive insulin delivery system composed of phenylboronic acid (PBA) groups was prepared and investigated. Complexation of various diol-containing molecules with PBA gel beads was evaluated using frontal chromatography. The structural features of the diol-containing molecules strongly influenced their binding to PBA gel beads. In particular, open-chain monosaccharides demonstrated higher association constants (ca 9.5 x 10(2) to 5.1 x 10(3) l/mol) than glucose (ca 6.3 x 10(2) l/mol). Furthermore, a model system utilizing a fluorescent derivative of tris(hydroxymethyl)aminomethane was synthesized and bound to PBA gel beads. The molecules were released in a pulsatile manner in response to glucose. In addition, gluconic acids were chemically attached to insulin molecules. The modified insulin, containing two gluconic acid units per insulin molecule, was isolated using ion-exchange chromatography. This gluconic acid-modified insulin (G-Ins) was bound onto a PBA gel column, and the G-Ins release profile in response to varying glucose concentrations was investigated. The results demonstrate that the PBA gel beads release G-Ins in response to glucose concentration. Thus, this new system may be applied for self-regulated insulin delivery.

Maf nuclear oncoprotein recognizes sequences related to an AP-1 site and forms heterodimers with both Fos and Jun

The v-maf oncogene, identified from AS42 avian retrovirus, encodes a nuclear bZip protein. To elucidate the molecular mechanism of cell transformation induced by this oncogene, we determined the specific binding sequences of its product. Maf protein recognized two types of relatively long palindromic consensus sequences, TGCTGACTCAGCA and TGCTGACGTCAGCA, at roughly equal efficiency. The middle parts of these Maf-binding sequences completely match with two binding sequences for AP-1 transcription factor, i.e., phorbol 12-O-tetradecanoate-13-acetate (TPA)-responsive element (TRE) and cyclic AMP responsive element, suggesting partial overlapping of the target genes for Maf and AP-1. Furthermore, Maf efficiently formed heterodimers with the components of AP-1, Fos and Jun, through their leucine zipper structures, and these heterodimers show binding specificities distinct from those for Maf-Maf and Jun-Jun homodimers. Thus, a multiple combination of the dimers should generate a greatly expanded repertoire of transcriptional regulatory potential. DNA data base search for the Maf-binding consensus sequences suggested that some of the TRE-like cis elements reported previously may actually be the targets for Maf family proteins or their heterodimers with other bZip proteins.

Effects of environmental parameters and composition of poly(2-hydroxyethyl methacrylate)-graft-polyamine copolymers on the retention of rat lymphocyte subpopulations (B- and T-cells)

Retention behavior of rat lymphocyte subpopulations (B- and T-cells) was investigated on poly(2-hydroxyethyl methacrylate)-graft-polyamine (HA) copolymers with various copolymer compositions. Separation mechanism of B- and T-cells was then evaluated by focusing on several parameters, such as pH, temperature, and ionic strength. The interaction of lymphocytes with HA surfaces was mainly through the electrostatic force from their retention profile at varying ionic strengths of the medium. Temperature also has a crucial effect on the response of lymphocytes toward pH-induced phase transition of polyamine grafts at the polymer interface with aqueous milieu. At 4 degrees C, both B- and T-cells showed minimal retention on HA surfaces at pH 8. At this pH, polyamine grafts existed in a compact conformation with a low degree of protonation. However, at pHs below 8, at which polyamine grafts existed in extended conformation, the resolution of B- and T-cells was achieved. In contrast, at 23 degrees C, the phase transition of polyamine grafts significantly influenced T-cell retention, resulting in a decrease in the retention of T-cells on HA with polyamine in a compact conformation. Consequently, preferential retention of B-cells was achieved under this condition. The polyamine content was found to be another important factor affecting the retention behavior of lymphocyte subpopulations. On HA copolymers with low polyamine content (HA7, HA10), conformational transition of polyamine grafts showed a significant influence for B-cell retention, although the influence decreased with increasing polyamine content. From the study estimating the effect of neuraminidase treatment of lymphocytes on their retention to HA surfaces, sialic acid residues on the plasma membrane surface of lymphocytes are suggested as feasible anionic sites showing electrostatic interaction with polyamine grafts.