Droplet-based valveless microfluidic system for phage-display screening against spheroids

In this study, we proposed a droplet-based valveless microfluidic system that has the necessary functions to perform the binding, washing, eluting, and collecting processes of phage-display screening against spheroids, which can be expected to present a similar repertoire and number of membrane proteins as in vivo. Although spheroids have much larger sizes than single cells, spheroids are difficult to manipulate through manual operation. The proposed microfluidic system actively controls the position and velocity of droplets using a camera, three air pumps, and three liquid pumps to perform the processes for phage-display screening. The cross section of the microchannel is large in width and height for the passage of spheroids. Valves that can close such a large cross-sectional microchannel are not readily available. Thus, we proposed valveless flow control using liquid pumps. In addition, the proposed microfluidic system involves complex flow channels with airflow subchannels to perform phage-display screening. For washing, nonspecific-binding phages remaining in the flow channels must be minimized. The proposed microfluidic system can perform selective blocking and flush washing. Selective blocking can prevent the airflow channels from becoming hydrophilic with blocking liquid, and flush washing can flush phages remaining in the flow channel. We experimentally verified the functions of the developed microfluidic device based on the proposed system.

Microfluidic High-Migratory Cell Collector Suppressing Artifacts Caused by Microstructures

The small number of high-migratory cancer cells in a cell population make studies on high-migratory cancer cells difficult. For the development of migration assays for such cancer cells, several microfluidic devices have been developed. However, they measure migration that is influenced by microstructures and they collect not only high-migratory cells, but also surrounding cells. In order to find high-migratory cells in cell populations while suppressing artifacts and to collect these cells while minimizing damages, we developed a microfluidic high-migratory cell collector with the ability to sort cancer cells according to cellular migration and mechanical detachment. High-migratory cancer cells travel further from the starting line when all of the cells are seeded on the same starting line. The high-migratory cells are detached using a stretch of cell adhesive surface using a water-driven balloon actuator. Using this cell collector, we selected high-migratory HeLa cells that migrated about 100m in 12 h and collected the cells.

New neurons use Slit-Robo signaling to migrate through the glial meshwork and approach a lesion for functional regeneration

After brain injury, neural stem cell-derived neuronal precursors (neuroblasts) in the ventricular-subventricular zone migrate toward the lesion. However, the ability of the mammalian brain to regenerate neuronal circuits for functional recovery is quite limited. Here, using a mouse model for ischemic stroke, we show that neuroblast migration is restricted by reactive astrocytes in and around the lesion. To migrate, the neuroblasts use Slit1-Robo2 signaling to disrupt the actin cytoskeleton in reactive astrocytes at the site of contact. Slit1-overexpressing neuroblasts transplanted into the poststroke brain migrated closer to the lesion than did control neuroblasts. These neuroblasts matured into striatal neurons and efficiently regenerated neuronal circuits, resulting in functional recovery in the poststroke mice. These results suggest that the positioning of new neurons will be critical for functional neuronal regeneration in stem/progenitor cell-based therapies for brain injury.

Fabrication of Pneumatic Microvalve for Tall Microchannel Using Inclined Lithography

We used inclined lithography to fabricate a pneumatic microvalve for tall microchannels such as those used to convey large cells. The pneumatic microvalve consists of three layers. The upper layer is the actual liquid microchannel, which has a parallelogram-shaped cross section of width 500 μm, height 100 μm, and an acute angle of 53.6°. The lower layer is a pneumatic microchannel that functions as an actuator, and the middle layer is a thin polydimethylsiloxane membrane between the upper and lower layers. The operation of the pneumatic microchannel actuator causes the thin membrane to bend, resulting in the bending of the liquid microchannel and its closure. It was confirmed that the closure of the liquid microchannel completely stopped the flow of the HeLa cell suspension that was used to demonstrate the operation of the microvalve. The HeLa cells that passed through the microchannel were also observed to retain their proliferation and morphological properties.

Assemblable Hand for Laparoscopic Surgery with Phased Array and Single-Element Ultrasound Probes

During laparoscopic surgery, large internal organs should often be manipulated while being internally visualized. For this purpose, we study an assemblable two-fingered hand implemented with an ultrasound probe. The fingers are separately introduced into the abdominal cavity through small incisions and are assembled into a hand sufficiently large to grasp or manipulate the large organ. Two types of ultrasound probes are employed; a phased array probe of a commercially available ultrasound diagnosis system, and a single-element probe. Using the latter probe, the hand is assembled through 12 mm trocars and is assessed in an in vivo experiment. Ultrasound echo sensing is found to retrieve diagnostic information regarding specific internal organs. It also visualizes the finger and its back during grasping, which can improve the safety of hand grasping and manipulation. Furthermore, ultrasound echo sensing can assist the measurement of the relative position and orientation of the two grasping fingers.

Holding Device with a Chain Net and its Modeling

A holding device with a chain net developed for automating and cutting labor in lifting has been used to remove wave-dissipating blocks and to recover hydrofoils from the seabed. It operates simply, but lifting safety must be rigorously checked, especially for heavy objects, so lifting models are highly desirable. We discuss modeling holding a four-leg block with the device, showing that its geometrical and static constraints are expressed as a set of nonlinear simultaneous equations having the same number of unknowns. From the solution to the simultaneous equations, the holding configuration and chain tension useful in determining whether the device can hold the block are obtained. Our proposal is also applicable to a four-leg block with a broken leg.

Genetically engineered mutant of the cyanobacterium Synechococcus PCC 7942 defective in nitrate transport

Nitrate-grown cells of Synechococcus PCC 7942 (Anacystis nidulans R2) contain a 45-kDa protein as a major protein in the cytoplasmic membrane but ammonium-grown cells lack it. A mutant (M45) was constructed by inactivating the gene encoding the 45-kDa protein. M45 did not grow under low concentrations of nitrate but high concentrations of nitrate could support its growth, with the optimal concentration being 40-70 mM. The growth rate of M45 was as high as that of the wild-type cells when ammonium was the nitrogen source. The 45-kDa protein was absent in M45 irrespective of the growth conditions. The activities of nitrate and nitrite reductases were higher in M45 than in wild type. The rate of nitrate-dependent O(2) evolution in wild type measured in the presence of L-methionine D,L-sulfoximine and D,L-glyceraldehyde showed saturation kinetics with respect to nitrate concentration in the external medium. The nitrate concentration required to produce half the maximal rate was 1 muM. In M45, the rate of nitrate-dependent O(2) evolution was nearly zero at nitrate concentrations <1 mM and was linearly increased as the concentration increased. The presumed absence of nitrate transport in M45 demonstrated by these results suggested that the 45-kDa protein is a nitrate transporter.

Role of NtcB in activation of nitrate assimilation genes in the cyanobacterium Synechocystis sp. strain PCC 6803

In Synechocystis sp. strain PCC 6803, the genes encoding the proteins involved in nitrate assimilation are organized into two transcription units, nrtABCD-narB and nirA, the expression of which was repressed by ammonium and induced by inhibition of ammonium assimilation, suggesting involvement of NtcA in the transcriptional regulation. Under inducing conditions, expression of the two transcription units was enhanced by nitrite, suggesting regulation by NtcB, the nitrite-responsive transcriptional enhancer we previously identified in Synechococcus sp. strain PCC 7942. The slr0395 gene, which encodes a protein 47% identical to Synechococcus NtcB, was identified as the Synechocystis ntcB gene, on the basis of the inability of an slr0395 mutant to rapidly accumulate the transcripts of the nitrate assimilation genes upon induction and to respond to nitrite. While Synechococcus NtcB strictly requires nitrite for its action, Synechocystis NtcB enhanced transcription significantly even in the absence of nitrite. Whereas the Synechococcus ntcB mutant expresses the nitrate assimilation genes to a significant level in an NtcA-dependent manner, the Synechocystis ntcB mutant showed only low-level expression of the nitrate assimilation genes, indicating that NtcA by itself cannot efficiently promote expression of these genes in Synechocystis. Activities of the nitrate assimilation enzymes in the Synechocystis ntcB mutant were consequently low, being 40 to 50% of the wild-type level, and the cells grew on nitrate at a rate approximately threefold lower than that of the wild-type strain. These results showed that the contribution of NtcB to the expression of nitrate assimilation capability varies considerably among different strains of cyanobacteria.

Involvement of a CbbR homolog in low CO2-induced activation of the bicarbonate transporter operon in cyanobacteria

The cmpABCD operon of Synechococcus sp. strain PCC 7942, encoding a high-affinity bicarbonate transporter, is transcribed only under CO2-limited conditions. In Synechocystis sp. strain PCC 6803, the slr0040, slr0041, slr0043, and slr0044 genes, forming an operon with a putative porin gene (slr0042), were identified as the cmpA, cmpB, cmpC, and cmpD genes, respectively, on the basis of their strong similarities to the corresponding Synechococcus cmp genes and their induction under low CO2 conditions. Immediately upstream of and transcribed divergently from the Synechocystis cmp operon is a gene (sll0030) encoding a homolog of CbbR, a LysR family transcriptional regulator of the CO2 fixation operons of chemoautotrophic and purple photosynthetic bacteria. Inactivation of sll0030, but not of another closely related cbbR homolog (sll1594), abolished low CO2 induction of cmp operon expression. Gel retardation assays showed specific binding of the Sll0030 protein to the sll0030-cmpA intergenic region, suggesting that the protein activates transcription of the cmp operon by interacting with its regulatory region. A cbbR homolog similar to sll0030 and sll1594 was cloned from Synechococcus sp. strain PCC 7942 and shown to be involved in the low CO2-induced activation of the cmp operon. We hence designated the Synechocystis sll0030 gene and the Synechococcus cbbR homolog cmpR. In the mutants of the cbbR homologs, upregulation of ribulose-1,5-bisphosphate carboxylase/oxygenase operon expression by CO2 limitation was either unaffected (strain PCC 6803) or enhanced (strain PCC 7942), suggesting existence of other low CO2-responsive transcriptional regulator(s) in cyanobacteria.

Effects of a novel hepatoprotective drug, ZNC-2381, on fas-induced hepatocellular caspase-3 activity and apoptosis in mice

We examined the effects of ZNC-2381 (1-(4-aminophenyl)methyl-3-(3-nitrophenyl)-1,3-dihydroimidazo[4,5-b] pyridine-2-one), a new oral hepatoprotective agent, on hepatocellular caspase-3 activity and apoptosis induced by anti-mouse Fas antibody (anti-Fas ab) in mice. Oral ZNC-2381, administered at doses of 10, 30 and 100 mg/kg 1 h before inducing hepatic injury with anti-Fas ab, dose-dependently inhibited the increase in serum alanine aminotransferase (s-ALT) activity 8 h after injection of anti-Fas ab. Increases in DNA fragmentation (nucleosome assay) and caspase-3 activity in the liver 2 h after injection of anti-Fas ab were also inhibited by ZNC-2381 in a dose-dependent manner. As shown by histopathological examination, ZNC-2381 dose-dependently inhibited the appearance of TUNEL-positive apoptotic cells in the liver. Moreover, in studies in vitro, ZNC-2381 (1- 100 micromol/l) concentration-dependently inhibited increases in DNA fragmentation and caspase-3 activity caused by anti-Fas ab in isolated mouse hepatocytes. N- Acetyl-Asp-Glu-Val-Asp aldehyde (Ac-DEVD-cho), a caspase-3-specific inhibitor, inhibited hepatocellular apoptosis caused by anti-Fas ab both in vivo and in vitro, as well as the increase in s-ALT activity in vivo. These results demonstrate that orally administered ZNC-2381 inhibits hepatocellular apoptosis induced by anti-Fas ab and presents the progression of hepatic injury. We propose that the mechanism of action of ZNC-2381 may involve blockade of the signal transduction pathway (caspase-3) of apoptosis mediated by anti-Fas ab.

Bicarbonate binding activity of the CmpA protein of the cyanobacterium Synechococcus sp. strain PCC 7942 involved in active transport of bicarbonate

The cmpABCD operon of the cyanobacterium Synechococcus sp. strain PCC 7942 encodes an ATP-binding cassette transporter involved in HCO(3)(-) uptake. The three genes, cmpBCD, encode membrane components of an ATP-binding cassette transporter, whereas cmpA encodes a 42-kDa cytoplasmic membrane protein, which is 46.5% identical to the membrane-anchored substrate-binding protein of the nitrate/nitrite transporter. Equilibrium dialysis analysis using H(14)CO(3)(-) showed that a truncated CmpA protein lacking the N-terminal 31 amino acids, expressed in Escherichia coli cells as a histidine-tagged soluble protein, specifically binds inorganic carbon (CO(2) or HCO(3)(-)). The addition of the recombinant CmpA protein to a buffer caused a decrease in the concentration of dissolved CO(2) because of the binding of inorganic carbon to the protein. The decrease in CO(2) concentration was accelerated by the addition of carbonic anhydrase, indicating that HCO(3)(-), but not CO(2), binds to the protein. Mass spectrometric measurements of the amounts of unbound and bound HCO(3)(-) in CmpA solutions containing low concentrations of inorganic carbon revealed that CmpA binds HCO(3)(-) with high affinity (K(d) = 5 microm). A similar dissociation constant was obtained by analysis of the competitive inhibition of the CmpA protein on the carboxylation of phosphoenolpyruvate by phosphoenolpyruvate carboxylase at limiting concentrations of HCO(3)(-). These findings showed that the cmpA gene encodes the substrate-binding protein of the HCO(3)(-) transporter.

Purkinje cell activity in the middle zone of the cerebellar flocculus during optokinetic and vestibular eye movement in cats

Based on the inverse dynamics theory, a previous paper reconstructed simple-spike (SS) firing rates of Purkinje cells in the cat's flocculus middle-zone by a linear-weighted summation of eye acceleration, velocity, and position during optokinetic response (OKR). The present study investigated the SS rates during combined optokinetic and vestibular stimuli of the cells recorded in the previous paper. During the sinusoidal vestibuloocular reflex (VOR) in the light (VORL) and in the dark (VORD) the firing modulation was small. During VOR suppression (VORS) by head and visual-pattern rotation in the same direction, the modulation was deep, with the peak coinciding roughly with peak ipsiversive head velocity. During VOR enhancement (VORE), the modulation was deep, with the peak coinciding roughly with peak contraversive head velocity. If we interpret these data in relation to eye and head movements, the cells in the cat were comparable to the horizontal-gaze-velocity Purkinje cells in the monkey that encode a linear summation of eye and head velocity signals. Alternatively, if we interpret the data on the basis of the inverse dynamics theory, the SS rates during VORL, VORS, and VORE were well-fitted by the OKR components of the movements (subtraction of VORD from VORL, VORS, and VORE eye movements, respectively), but not by the whole movements, using the coefficients calculated during OKR. It is concluded that the data are interpretable by both theories when the VOR gain (eye movement/head movement) is close to 1 and the firing is dominated by eye velocity information.

Usefulness and pitfalls of intraoperative spinal motor evoked potential recording by direct cortical electrical stimulation

OBJECTIVE

The aim of this study is to investigate the usefulness and problems with spinal motor evoked potential (MEP) recording, especially the reasons for failed recording. We report our personal experience over the last 8 years in patients with lesions adjacent to the primary motor cortex.

METHODS

MEP records of 50 consecutive patients were retrospectively reviewed. MEP was recorded by a catheter electrode inserted in the cervical epidural space. Stimulation electrodes were placed on the cortical surface during surgery. SEP recording was also performed in 29 of 50 patients.

RESULTS

MEP was obtained in 40 cases, and SEP was recorded in all 29 cases. The central sulcus was identified in 93% of patients in whom both MEP and SEP were performed, whereas in only 86% of patients who underwent only MEP. The main reason for MEP failure were inadequate exposure of the motor cortex, pre-existing hemiparesis and technical errors. Postoperative deterioration of motor function was closely related to intra-operative MEP changes.

CONCLUSION

MEP is a useful tool to determine the motor cortex and to predict postoperative motor function. However, precise pre-operative craniotomy planning and combination with intra-operative SEP is essential to reduce the MEP failure.

Effects of ZNC-2381, a new oral compound, on several hepatic injury models and on hepatocellular apoptosis in mice and rats

The hepatoprotective effect of ZNC-2381 (1-(4-aminophenyl) methyl-3-(3-nitrophenyl)-1,3-dihydroimidazo[4,5-b]pyridine-2-one), a novel 2-one dihydroimidazopyridine derivative, has been evaluated in several experimental models of hepatic injury. In mice, oral ZNC-2381, administered at doses of 3, 10 or 30 mgkg(-1), 1 h before induction of hepatic injury with concanavalin A, dose-dependently inhibited increases in serum alanine aminotransferase (ALT) activity. Apoptosis of liver cells, as indicated by DNA fragmentation (nucleosome assay) and DNA-ladder formation (electrophoresis), was also inhibited dose-dependently. ZNC-2381 dose-dependently inhibited concanavalin A-induced increases in serum tumour necrosis factor (TNF)-alpha levels, and TNF-alpha mRNA expression in the liver. Oral ZNC-2381 also dose-dependently inhibited increases in serum ALT activity in mice with hepatic injury induced by Propionibacterium acnes and a bacterial lipopolysaccharide (LPS) or D-galactosamine-LPS, and in rats with D-galactosamine-induced hepatic injury. These results indicate that oral ZNC-2381 inhibits cytokine (TNF-alpha) production and cytokine-related hepatocellular apoptosis, and might thus prevent different types of hepatic injury.

Motor dynamics encoding in the rostral zone of the cat cerebellar flocculus during vertical optokinetic eye movements

The complex spike (CS) and simple spike (SS) activities of Purkinje cells in the rostral zone of the cerebellar flocculus were recorded in alert cats during optokinetic responses (OKR) elicited by a stimulus sequence consisting of a constant-speed visual pattern movement in one direction for 1 s and then in the opposite direction for 1 s. The quick-phase-free trials were selected. Ninety-eight cells were identified as rostral zone cells by the direction-selective CS activity that was modulated during vertical but not horizontal stimuli. In most of the majority population (88 cells), with an increasing CS firing rate during upward OKR and an increasing SS rate during downward OKR, the inverse dynamics approach was successful and the time course of the SS rate was reconstructed (mean coefficient of determination, 0.70 and 0.72 during upward and downward stimuli, respectively) by a linear weighted superposition of the eye acceleration, velocity, position, and constant terms, at a given time delay (mean 10 ms) from the unit response to the eye-movement response. Standard regression coefficient (SRC) analysis revealed that the contribution of the velocity term (mean SRC 0.98 for upward and 0.80 for downward) to regression was dominant over acceleration (mean SRC 0.018 and 0.058) and position (-0.14 and -0.12) terms. The velocity coefficient during upward stimuli (6.6 spikes/s per degree/s) was significantly (P<0.01) larger than that during downward stimuli (4.9 spikes/s per degree/s). In most of the minority population (10 cells), with both CS and SS firing rates increasing during upward OKR, the inverse dynamics approach was not successful. It is concluded that 1) in the cat rostral zone Purkinje cells, in which the preferred direction is upward for CS and downward for SS, eye velocity and acceleration information is encoded in SS firing to counteract the viscosity and inertia forces, respectively, on the eye during vertical OKR; 2) the eye position information encoded in SS firing is inappropriate for counteracting the elastic force; 3) encoding of eye velocity information during upward OKR is quantitatively different from that during downward OKR: SS firing modulation is larger for upward than for downward OKR of the same amplitude; and 4) encoding of motor dynamics is obscure in cells in which the preferred direction is upward for both CS and SS.

Effects of chondroitin sulfate-C on articular cartilage destruction in murine collagen-induced arthritis

The effects of chondroitin sulfate-C (CAS 25322-46-7, Chondroitin ZS Tab) on type II collagen (CII)-induced arthritis (CIA) in mice were evaluated. DBA/1J mice were immunized with bovine CII emulsified in Freund's complete adjuvant, followed by a booster injection 21 days later. Chondroitin sulfate-C at doses of 100, 300 and 1000 mg/kg was administered orally once daily beginning 14 days before initial immunization. An arthritis index and hind paw edema were examined from day 0 to day 49, when the mice were killed by ether anesthesia for histopathological examination. The delayed-type hypersensitivity (DTH) reaction, serum anti-CII antibody titer, and histopathologic characteristics of both synovitis and destruction of articular cartilage were analyzed. Both the arthritis index and the serum anti-CII antibody titer were reduced by treatment with chondroitin sulfate-C in a dose-dependent manner. Chondroitin sulfate-C (1000 mg/kg) significantly inhibited hind paw edema, synovitis and destruction of the articular cartilage, but not DTH reaction.

[A case of famotidine-induced aseptic meningitis]

We reported a 50-year-old woman with a history of mixed connective tissue disease. She had two episodes of meningitis-like symptoms after taking famotidine and tiquizium bromide for treatment of gastric ulcer. From CSF findings (elevated pressure, increase of protein, polymorphonuclear pleocytosis, negative culture) and result of famotidine challenge test, we diagnosed her as a drug induced aseptic meningitis. Because she had taken tiquizium bromide several times previously without any side effects, we concluded that famotidine was a causative drug. She was recovered without sequelae within a few days following cessation of these drugs. This is the first report of H2-blocker induced aseptic meningitis. When we encounter a patient with aseptic meningitis who presents polymorphonuclear pleocytosis in CSF, we should suspect drug induced aseptic meningitis and take a history of drug medication including H2-blocker.

Identification of an ATP-binding cassette transporter involved in bicarbonate uptake in the cyanobacterium Synechococcus sp. strain PCC 7942

Exposure of cells of cyanobacteria (blue-green algae) grown under high-CO(2) conditions to inorganic C-limitation induces transcription of particular genes and expression of high-affinity CO(2) and HCO(3)(-) transport systems. Among the low-CO(2)-inducible transcription units of Synechococcus sp. strain PCC 7942 is the cmpABCD operon, encoding an ATP-binding cassette transporter similar to the nitrate/nitrite transporter of the same cyanobacterium. A nitrogen-regulated promoter was used to selectively induce expression of the cmpABCD genes by growth of transgenic cells on nitrate under high CO(2) conditions. Measurements of the initial rate of HCO(3)(-) uptake after onset of light, and of the steady-state rate of HCO(3)(-) uptake in the light, showed that the controlled induction of the cmp genes resulted in selective expression of high-affinity HCO(3)(-) transport activity. The forced expression of cmpABCD did not significantly increase the CO(2) uptake capabilities of the cells. These findings demonstrated that the cmpABCD genes encode a high-affinity HCO(3)(-) transporter. A deletion mutant of cmpAB (M42) retained low CO(2)-inducible activity of HCO(3)(-) transport, indicating the occurrence of HCO(3)(-) transporter(s) distinct from the one encoded by cmpABCD. HCO(3)(-) uptake by low-CO(2)-induced M42 cells showed lower affinity for external HCO(3)(-) than for wild-type cells under the same conditions, showing that the HCO(3)(-) transporter encoded by cmpABCD has the highest affinity for HCO(3)(-) among the HCO(3)(-) transporters present in the cyanobacterium. This appears to be the first unambiguous identification and description of a primary active HCO(3)(-) transporter.

Motor dynamics encoding in cat cerebellar flocculus middle zone during optokinetic eye movements

We investigated the relationship between eye movement and simple-spike (SS) frequency of Purkinje cells in the cerebellar flocculus middle zone during the optokinetic response (OKR) in alert cats. The OKR was elicited by a sequence of a constant-speed visual pattern movement in one direction for 1 s and then in the opposite direction for 1 s. Quick-phase-free trials were selected. Sixty-six cells had direction-selective complex spike (CS) activity that was modulated during horizontal (preferring contraversive) but not vertical stimuli. The SS activity was modulated during horizontal OKR, preferring ipsiversive stimuli. Forty-one cells had well-modulated activity and were suitable for the regression model. In these cells, an inverse dynamics approach was applied, and the time course of the SS rate was reconstructed, with mean coefficient of determination 0.76, by a linear weighted superposition of the eye acceleration (mean coefficient, 0.056 spikes/s per deg/s(2)), velocity (5.10 spikes/s per deg/s), position (-2.40 spikes/s per deg), and constant (mean 34.3 spikes/s) terms, using a time delay (mean 11 ms) from the unit response to the eye response. The velocity and acceleration terms contributed to the increase in the reconstructed SS rates during ipsilateral movements, whereas the position term contributed during contralateral movements. The standard regression coefficient analyses revealed that the contribution of the velocity term (mean coefficient 0.81) was predominant over the acceleration (0.03) and position (-0.17) terms. Forward selection analysis revealed three cell types: Velocity-Position-Acceleration type (n = 27): velocity, position, and acceleration terms are significant (P < 0.05); Velocity-Position type (n = 12): velocity and position terms are significant; and Velocity-Acceleration type (n = 2): velocity and acceleration terms are significant. Using the set of coefficients obtained by regression of the response to a 5 deg/s stimulus velocity, the SS rates during higher (10, 20, and 40 deg/s) stimulus velocities were successfully reconstructed, suggesting generality of the model. The eye-position information encoded in the SS firing during the OKR was relative but not absolute in the sense that the magnitude of the position shift from the initial eye position (0 deg/s velocity) contributed to firing rate changes, but the initial eye position did not. It is concluded that 1) the SS firing frequency in the cat middle zone encodes the velocity and acceleration information for counteracting the viscosity and inertia forces respectively, during short-duration horizontal OKR and 2) the apparent position information encoded in the SS firing is not appropriate for counteracting the elastic force during the OKR.

D-galactosamine-induced mouse hepatic apoptosis: possible involvement with tumor necrosis factor, but not with caspase-3 activity

We investigated whether tumor necrosis factor (TNF) and caspase-3 activity are involved in the induction of hepatocellular apoptosis in D-galactosamine (D-GalN)-induced hepatotoxicity in mice. Acute hepatotoxicity was induced by the intraperitoneal injection of D-GalN into female BALB/c mice. D-GalN (0.75-3.0 g/kg) increased the serum glutamate pyruvate transaminase (s-GPT) activity and the percentage of liver DNA fragmentation, an indicator of hepatotoxicity, after 48 h, in a dose-dependent manner. Furthermore, after D-GalN (3.0 g/kg) administration, increased liver DNA fragmentation was detected biochemically at 24 h, then increased s-GPT activity accompanied by increased liver DNA fragmentation was observed after 48 h. The serum TNF (s-TNF) level and the TNF mRNA expression in the liver after D-GalN (3.0 g/kg, i.p.) administration were examined by an ELISA kit and reverse transcription polymerase chain reaction (RT-PCR), respectively, to investigate the relation between the s-GPT activity and liver DNA fragmentation. The s-TNF level and TNF mRNA expression in the liver after D-GalN (3.0 g/kg) administration were detected earlier than liver DNA fragmentation, then increased with time. However, there was almost no association of caspase-3 activity with the increase in liver DNA fragmentation. Increases in the s-TNF level, TNF mRNA expression and the percentage of DNA fragmentation in the liver and s-GPT activity were inhibited by dexamethasone (Dex; 0.4-2.5 mg/kg, i.p.) in a dose-dependent manner. Based on these findings, it was considered that the intracellular apoptosis signal in D-GalN-induced hepatotoxicity in mice did not depend on caspase-3 activity, and that other signals mediated by TNF may be involved.

Postoperative oblique sagittal MR imaging of microvascular decompression for hemifacial spasm

Pre-operative and postoperative oblique sagittal gradient-echo magnetic resonance (MR) imaging was used to evaluate micro-vascular decompression of the facial nerves in 26 patients with hemifacial spasm. The pre-operative MR images were divided into two groups as follows: 22 images in Group I, clear imaging of a high-intensity line and/or spot at the root exit zone (REZ) of the facial nerve; and 4 in Group II, and unreliable image around the REZ. Surgery found that the causative vessel was the vertebral artery (VA) in 9 cases and the anterior inferior cerebellar artery (AICA) or the posterior inferior cerebellar artery (PICA) in 13 cases in Group I, and the AICA or the PICA in the 4 cases in Group II. Postoperative MR imaging showed clear decompression as the high-intensity line and/or spot completely separated from the REZ by a low- and/or iso- intensity area in 9 cases of VA compression repositioned to the petrous dura matter, in 11 cases of PICA or AICA compression treated by shredded Teflon pledgets in Group I and in 3 cases in Group II. Postoperative MR imaging showed an incomplete separation of any high-intensity line and/or spot in the REZ in 2 cases of PICA or AICA compression in Group I and in one in Group II. The outcome was excellent in 22 of 23 cases with clear decompression, and in 1 of 3 cases of unclear decompression. Hemifacial spasm persisted in 3 cases. Oblique sagittal gradient-echo MR imaging is a useful method for postoperative follow-up which can demonstrate changes around the REZ of the facial nerve if hemifacial spasm recurs.

Effects of chondroitin sulfate-C on bradykinin-induced proteoglycan depletion in rats

Depletion of the proteoglycan content of articular cartilage was induced by injecting bradykinin (30-300 mumol/l, 50 microliters/knee) into the left knee articular cavities of rats 3 times a day for 2 days. The degree of the reduction in the intensity of histopathological safranin O staining was used as an index of proteoglycan depletion. Bradykinin reduced the cartilage proteoglycan contents of the knee joints of non-injected limbs in a dose-dependent manner and at 300 mumol/l markedly reduced these contents, but evoked no inflammatory changes. The extent of the reduction of the cartilage proteoglycan contents induced by bradykinin injection depended on the dose and injection frequency. Chondroitin sulfate-C (CAS 25322-46-7, Chondroitin ZS Tab) (30-1,000 mg/kg/day) administered orally to rats for 14 days inhibited the bradykinin-induced proteoglycan depletion of the articular cartilage in a dose-dependent manner. These results suggest that a reduction of the proteoglycan content of cartilage, like that associated with osteoarthritis, was induced by injecting bradykinin into the knee articular cavities of rats and chondroitin sulfate-C protected against this effect.

Lipase-catalyzed kinetic resolution of 2,3-epoxy-1-tridecanol and its application to facile synthesis of (+)-disparlure

Acylation of (+/-)-2,3-epoxy-1-tridecanol with acetic anhydride in diisopropyl ether by porcine pancreatic lipase yielded (2R, 3S)-2,3-epoxy-1-tridecanol as the remaining substrate with an optical purity of over 99% ee. (+)-Disparlure was synthesized in two steps from this optically active epoxy alcohol.

Age-depending effects of methotrexate treatment on systemic bone turnover in experimental adjuvant arthritis

Adjuvant arthritis was induced in rats in the growth stage (aged 6 weeks) and those in the mature stage (aged 4 months), and changes in the systemic bone turnover and the effects of methotrexate (MTX, CAS 133073-73-1) were compared. After induction of adjuvant arthritis, the paw edema ratio and the urinary deoxypyridinoline (u-Dpy) level increased in both age groups. No marked changes were observed in the serum osteocalcin (s-OC) level in either group. In the 6-week-old rats, arthritis completely inhibited the bone mass, and strength of the femur and lumbar vertebral body. The 4-month-old rats showed more marked changes than the 6-week-old rats in the bone mass and strength of the lumbar, vertebral body. MTX administration (0.05, 0.1 and 0.2 mg/kg/day) resulted in significant dose-dependent inhibition of arthritis-induced changes, and the effects of MTX were similar between the two age groups. MTX was useful at each age. These results suggest that 4-month-old rats with arthritis are more appropriate as a model for evaluation of drugs for bone metabolic turnover in human chronic rheumatoid arthritis.

Nitrite-specific active transport system of the cyanobacterium Synechococcus sp. strain PCC 7942

Studies on the nitrite uptake capability of a mutant of Synechococcus sp. strain PCC 7942 lacking the ATP-binding cassette-type nitrate-nitrite-bispecific transporter revealed the occurrence of a nitrite-specific active transport system with an apparent Km (NO2-) of about 20 microM. Similar to the nitrate-nitrite-bispecific transporter, the nitrite-specific transporter was reversibly inhibited by ammonium in the medium.

Prediction of vertebral artery compression in patients with hemifacial spasm using oblique sagittal MR imaging

To discriminate between the various compressing vessels of the facial nerves in patients with hemifacial spasm, pre-operative oblique sagittal gradient-echo MR imaging was performed. Forty-two patients underwent pre-operative MR imaging and microvascular decompression. The MR images were divided according to findings into three groups as follows: Group A, a thick and/or long high-intensity line along the root exit zone (REZ) of the facial nerve; Group B, a thin and/or short high-intensity line along the REZ; and Group C, an unreliable image around the REZ. Fifteen images were classified as Group A, 19 as Group B, and 8 as Group C. In Group A, vertebral artery (VA) compression was confirmed intra-operatively in 12 cases and posterior inferior cerebellar artery (PICA) or anterior inferior cerebellar artery (AICA) compression in 3. In Group B, PICA or AICA compression was confirmed intra-operatively in all cases. In Group C, PICA or AICA compression was confirmed intra-operatively in 7 cases and no compression in one. In all cases of VA compression of the facial nerve, the oblique sagittal gradient-echo images demonstrated a thick and/or long high intensity line along the REZ. Oblique sagittal gradient-echo MR imaging is a useful preoperative planning aid, which can predict the possibility of VA compression prior to microvascular decompression for hemifacial spasm.

Independence of carbon and nitrogen control in the posttranslational regulation of nitrate transport in the cyanobacterium Synechococcus sp. strain PCC 7942

Nitrate transport by Synechococcus sp. strain PCC 7942 cells was inhibited by ammonium and by inhibitors of CO2 fixation. Ammonium assimilation inhibitors, such as L-methionine D,L-sulfoximine, were known to prevent the negative effects of ammonium and of inhibitors of CO2 fixation on nitrate uptake, leading to propose that CO2 fixation was required to counteract the feed-back inhibition of nitrate assimilation. In NR-less mutants, L-methionine D,L-sulfoximine prevented the negative effects of ammonium on nitrate transport, but not always prevented those of inhibiting CO2 fixation. The carboxy-terminal domain of the NrtC subunit of the nitrate transporter has recently been identified as a regulatory domain involved in N-control. The mutant strain NC2, constructed by deleting the 3' portion of nrtC, showed high nitrate transport activity insensitive to ammonium but sensitive to inhibitors of CO2 fixation. These findings indicate that the C-control and the N-control of nitrate transport are independent at both the physiological and the molecular level.

cis-acting sequences required for NtcB-dependent, nitrite-responsive positive regulation of the nitrate assimilation operon in the cyanobacterium Synechococcus sp. strain PCC 7942

There are three binding sites for NtcA (nirI, nirII, and nirIII), the global nitrogen regulator of cyanobacteria, in the DNA region between the two divergently transcribed operons (nirA and nirB operons) involved in nitrate assimilation in Synechococcus sp. strain PCC 7942. Using the luxAB reporter system, we showed that nirI and nirIII, which are located 23 bp upstream from the -10 promoter element of nirA and nirB, respectively, are required for induction by nitrogen depletion of the nirA and nirB operons, respectively. The induction of nirA operon transcription was a prerequisite for the nitrite-responsive positive regulation of the transcription by NtcB, a LysR-type protein. The NtcA-binding site nirII, located in the middle of the nirA-nirB intergenic region, and a potential binding site for a LysR-type protein (TGCAN5TGCA; designated L1), located between nirI and nirII, were required for the nitrite-responsive, NtcB-dependent enhancement of nirA operon transcription. Although the requirement for the L1 site was consistent with the involvement of the LysR family protein NtcB in transcriptional regulation, NtcB did not bind to the nirA regulatory region in vitro in the presence of nitrite and NtcA, suggesting the involvement of some additional factor(s) in the regulation. An L1-like inverted repeat with the consensus sequence TGCN7GCA was conserved in the nirA promoter region of cyanobacteria, being centered at position -23 with respect to the NtcA-binding site corresponding to nirI, which suggested the common occurrence of nitrite-responsive regulation of the nitrate assimilation operon among cyanobacteria.

Promoters of the phycocyanin gene clusters of the cyanobacterium Synechococcus sp. strain PCC 7942

The cyanobacterium Synechococcus sp. strain PCC 7942 has duplicated phycocyanin subunit gene clusters cpcB1A1 and cpcB2A2, which are identical to each other and to those of Synechococcus sp. strain PCC 6301 (Anacystis nidulans). Nucleotide sequences of the 428 and 286 bases of the 5' non-coding regions of the cpcB1A1 and cpcB2A2 clusters, respectively, of strain PCC 7942 were identical to those of strain PCC 6301. As in strain PCC 6301, cpcB1A1 yielded two major transcripts of 1.4 and 1.3 kb and cpcB2A2 yielded a single transcript of 1.3 kb in strain PCC 7942. Thus, the structure and expression of cpcBA gene clusters in the two strains are essentially the same. Using bacterial luciferase encoded by luxAB as a reporter, cpcB1A1 was shown to have two promoters corresponding to the two major transcripts. Luminescence from the Synechococcus reporter strains carrying the fusions of the cpcBA promoters to luxAB showed circadian oscillation. Similar to the promoter of psbA1 encoding the D1 protein of PSII, the two cpcB1A1 promoters and the cpcB2A2 promoter showed the peak of activity at the end of the subjective day and the trough at the end of the subjective night.

Involvement of the C-terminal domain of an ATP-binding subunit in the regulation of the ABC-type nitrate/nitrite transporter of the Cyanobacterium synechococcus sp. strain PCC 7942

In Synechococcus sp. strain PCC 7942, an ATP-binding cassette transporter encoded by the genes nrtA, nrtB, nrtC, and nrtD mediates active transport of nitrate and nitrite, which is inhibited by ammonium, a preferred source of nitrogen for the cyanobacterium. One of the ATP-binding subunits of the transporter, NrtC, has a distinct C-terminal domain of 380 amino acid residues. A mutant NC2, constructed by removal of this domain using genetic engineering techniques, assimilated low concentrations of nitrate and nitrite and accumulated nitrate intracellularly, showing that the domain is not essential for the transporter activities. Assimilation of low concentrations of nitrite was only partially inhibited by ammonium in NC2 but was completely inhibited in the wild-type cells. Cells of NC2 and its derivative (nitrate reductase-less strain NC4) carrying the truncated NrtC but not the cells with the wild-type NrtC accumulated nitrate intracellularly in the presence of ammonium in medium. These findings indicated that the C-terminal domain of NrtC is involved in the ammonium-promoted inhibition of the nitrate/nitrite transporter. In the presence of ammonium, NC2 could not assimilate nitrate despite its ability to accumulate nitrate intracellularly, which suggested that reduction of intracellular nitrate by nitrate reductase is also subject to inhibition by ammonium.

Methotrexate suppresses nitric oxide production ex vivo in macrophages from rats with adjuvant-induced arthritis

We examined the effects of methotrexate (MTX) on the level of nitric oxide (NO) produced by peritoneal macrophages from rats with adjuvant-induced arthritis (AA) ex vivo. During the development of AA, paw swelling increased and LPS enhanced the capacity of peritoneal macrophages to produce NO and prostaglandin E2 (PGE2). MTX (0.1 mg/kg, p.o.) treatment for 21 days reduced the paw swelling, and inhibited the increased NO and PGE2 production. However, when MTX (0.1 mg/kg, p.o.) was administered to rats with established AA, these parameters were not significantly influenced. In normal rats, MTX (0.1 mg/kg, p.o.) treatment for 21 days did not change NO and PGE2 production of LPS-stimulated macrophages. On the other hand, macrophages from normal and AA rats cultured in the presence of MTX (1, 10 and 100 microM), were activated by LPS in vitro. MTX did not influence NO or PGE2 production by LPS-stimulated macrophages in normal and AA rats. By contrast, indomethacin (IM) (1.0 mg/kg, p.o.) treatment for 21 days reduced the paw swelling, and inhibited NO and PGE2 production in AA rats. IM inhibited significantly PGE2 production, but did not influence NO production by LPS-stimulated macrophages in vitro. These results suggest that MTX treatment reduces NO production in peritoneal macrophages in AA rats, and these actions of MTX may have an inhibitory effect without the modulation of PGE2.

Identification and nitrogen regulation of the cyanase gene from the cyanobacteria Synechocystis sp. strain PCC 6803 and Synechococcus sp. strain PCC 7942

An open reading frame (slr0899) on the genome of Synechocystis sp. strain PCC 6803 encodes a polypeptide of 149 amino acid residues, the sequence of which is 40% identical to that of cyanase from Escherichia coli. Introduction into a cyanase-deficient E. coli strain of a plasmid-borne slr0899 resulted in expression of low but significant activity of cyanase. Targeted interruption of a homolog of slr0899 from Synechococcus sp. strain PCC 7942, encoding a protein 77% identical to that encoded by slr0899, resulted in loss of cellular cyanase activity. These results indicated that slr0899 and its homolog in the strain PCC 7942 represent the cyanobacterial cyanase gene (designated cynS). While cynS of strain PCC 6803 is tightly clustered with the four putative molybdenum cofactor biosynthesis genes located downstream, cynS of strain PCC 7942 was found to be tightly clustered with the two genes located upstream, which encode proteins similar to the subunits of the cyanobacterial nitrate-nitrite transporter. In both strains, cynS was transcribed as a part of a large transcription unit and the transcription was negatively regulated by ammonium. Cyanase activity was low in ammonium-grown cells and was induced 7- to 13-fold by inhibition of ammonium fixation or by transfer of the cells to ammonium-free media. These findings indicated that cyanase is an ammonium-repressible enzyme in cyanobacteria, the expression of which is regulated at the level of transcription. Similar to other ammonium-repressible genes in cyanobacteria, expression of cynS required NtcA, a global nitrogen regulator of cyanobacteria.

Involvement of NtcB, a LysR family transcription factor, in nitrite activation of the nitrate assimilation operon in the cyanobacterium Synechococcus sp. strain PCC 7942

Nitrite, either exogenously supplied or endogenously generated by nitrate reduction, activates transcription of the nitrate assimilation operon (nirA-nrtABCD-narB) in Synechococcus sp. strain PCC 7942 cells treated with L-methionine-DL-sulfoximine (an inhibitor of glutamine synthetase), in which there is no negative feedback resulting from fixation of the ammonium generated by nitrite reduction (Kikuchi et al., J. Bacteriol. 178:5822-5825, 1996). Other transcription units related to nitrogen assimilation, i.e., the nirB-ntcB operon, glnA, and ntcA, were not activated by nitrite. Nitrite did not activate nirA operon transcription in a mutant with a deletion of ntcB, an ammonium-repressible gene encoding a LysR-type DNA-binding protein. Introduction of plasmid-borne ntcB into the ntcB deletion mutant restored the response of the cells to nitrite, indicating that NtcB activates the nirA operon in response to nitrite. Supplementation of nitrite or nitrate to nitrogen-starved cultures of the wild-type strain, but not of the ntcB deletion mutant, caused activation of the nirA operon without L-methionine-DL-sulfoximine treatment of the cells. The results suggested that the positive-regulation mechanism of nirA operon transcription plays a role in rapid adaptation of nitrogen-starved cells to changing availability of nitrate and nitrite.

Z-100, extracted from Mycobacterium tuberculosis strain Aoyama B, inhibits the development of collagen-induced arthritis in mice

We evaluated the effects of Z-100, extracted from human type Mycobacterium tuberculosis strain Aoyama B, on collagen-induced arthritis (CIA) in mice. One hundred thirty-five DBA/1J mice, 8 weeks of age, were assigned to 9 groups and immunized with bovine type II collagen (CII) or CFA. From the next day, Z-100 at doses of 0.004, 0.04, or 0.4 mg/kg B.W./d for 48 d was intradermally injected into the tail base. Methotrexate (MTX) at daily doses of 0.1, 0.3, or 1.0 mg/kg B.W. and cyclophosphamide (CY) at a daily dose of 5 mg/kg B.W. were used as reference drugs. The effects of these drugs on CIA mice were evaluated in terms of the incidence of CIA, the arthritis index (AI), and hind paw edema, after which the animals were sacrificed at 49 d, and both anti-CII antibody titer and delayed-type hypersensitivity (DTH) reaction were measured. In the arthritic control groups, the AI and hind paw edema were significantly increased after the second immunization on day 28. The anti-CII antibody titer and DTH reaction were significantly increased compared to normal mice on day 49. Z-100 significantly inhibited the AI at a dose of 0.4 mg/kg/d on day 49, and suppressed the incidence of both CIA and hind paw edema. Increases in both anti-CII antibody titer and DTH reaction in CIA mice were prevented by treatment with Z-100 at 0.4 mg/kg/d. MTX, in a dose-dependent manner, and CY, at a dose of 5 mg/kg/d, inhibited the incidence of CIA, AI, hind paw edema, anti-CII antibody titer and DTH reaction in CIA mice. Z-100 at a dose of 0.4 mg/kg was as effective as MTX was at a dose of 0.3 mg/kg against the DTH reaction, and it had no side effects. These results suggest the usefulness of Z-100 in patients with chronic rheumatoid arthritis.