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Abstract.: We investigated the antibacterial activity of 12 antibiotics, inclusive of four carbapenems, against 167 strains of respiratory pathogens isolated between 1999 and 2000. Thirty strains of methicillin-susceptible Staphylococcus aureus (MSSA), 28 strains of methicillin-resistant S. aureus (MRSA), 11 strains of penicillin-susceptible Streptococcus pneumoniae (PSSP), 29 strains of penicillin-resistant S. pneumoniae (PRSP), 30 strains of Pseudomonas aeruginosa, 14 strains of Moraxella catarrhalis, and 25 strains of Haemophilus influenzae were examined. The minimum inhibitory concentration (MICs)50/90 (μg/ml) of imipenem, panipenem, meropenem, and biapenem against the clinical isolates obtained between 1999 and 2000 were: 0.06/0.25, 0.12/0.25, 0.12/0.25, and 0.12/0.25, respectively, against MSSA; 16/32, 16/32, 16/32, and 8/32 against MRSA; ≦0.015/0.06, ≦0.015/0.03, 0.03/0.12, and ≦0.015/0.06 against PSSP; 0.12/0.25, 0.03/0.06, 0.25/0.5, and 0.12/0.25 against PRSP; 1/8, 2/8, 0.5/2, and 2/16 against P. aeruginosa; 0.06/0.06, 0.03/0.06, ≦0.015/0.06, and 0.06/0.12 against M. catarrhalis; and 1/4, 1/4, 0.12/0.25, and 2/4 against H. influenzae. A comparison of the antibacterial activity of the four carbapenems with that found in our previous studies showed no significant difference in the susceptibility of clinical isolates, except for a slight decrease in the susceptibility of MSSA. Carbapenems have remained effective for severe infections. The MIC data showed that imipenem and panipenem were more active than meropenem and biapenem against gram-positive bacteria, and that meropenem and biapenem were more active than imipenem and panipenem against gram-negative bacteria. As only meropenem had an MIC90 below the breakpoint of pneumonia against all species except MRSA, meropenem was considered to be the most potent of the four carbapenems studied.

1. We define absolute sensitivity as (voltage/illuminance) and incremental sensitivity as the peak-to-peak amplitude of the first-order (Wiener) kernels. 2. Incremental sensitivity of the horizontal cells is the local slopes of the Michaelis-Menten equation and that of more proximal neurons is the Fechner slope. In a log-log plot, the former has a slope of -2, whereas the latter a slope of -1, as predicted by Williams and Gale (39). 3. During a moderate to strong steady illumination, absolute sensitivity decreases but incremental sensitivity increases. The reverse occurs during dark adaptation. 4. The presence of a steady illumination did not prevent signal transmission from horizontal to ganglion cells. 5. From these results we conclude that: adaptation in the catfish retina includes two components: a) a lateral shift of the voltage-intensity curve along the intensity axis, and b) changes in the time course of light-evoked response. We argue that the latter phenomenon is related to the presumed horizontal cell-to-receptor cell negative feedback.

1. The effects of the Na+ electrochemical potential gradient on gamma‐aminobutyric acid (GABA)‐induced Cl‐ currents (ICl) in frog sensory neurones were studied, using a suction pipette technique with which internal perfusion can be accomplished under current‐ and voltage‐clamp conditions. 2. Under current clamp, the depolarizing response to GABA decreased in the presence of external Na+. A similar external Na+‐dependent reduction in the GABA‐induced inward ICl was observed under voltage clamp. The reversal potential of GABA‐induced ICl (EGABA) was nearly equal to the Cl‐ equilibrium potential (ECl), irrespective of the presence or absence of external Na+. 3. Varying the Na+ influx by changing the holding membrane potential (VH) altered the GABA response: the GABA‐induced ICl decreased progressively as VH became more negative. 4. The effects of changing the external and internal Na+ concentrations ([Na+]o and [Na+]i) on the GABA‐induced ICl were also studied. Increasing [Na+]o at a constant [Na+]i reduced this current while increasing [Na+]i at a fixed [Na+]o facilitated it. 5. A high temperature coefficient of about 3 was estimated with respect to the percentage reduction in GABA‐induced ICl due to [Na+]o. 6. These results indicate that the [Na+]o‐dependent suppression of GABA‐induced ICl was mediated chiefly by the uptake of GABA subserved by a Na‐GABA co‐transport mechanism. 7. GABA dose‐response measurements were made with and without external Na+. The [Na+]o‐induced suppression was more pronounced in relative amount at lower concentrations and in absolute amount at intermediate concentrations. Analysis of these data indicates, however, that the Na+‐coupled GABA influx kept increasing at GABA concentrations high enough to nearly saturate GABA‐induced ICl, and the same saturating level was observed as in the Na+‐free case. This indicates that the electrogenic co‐transport current was much smaller so that our measurements of GABA‐induced ICl' were contaminated very little. Thus, the present method based on recording of GABA‐induced ICl was legitimate for the analysis of the Na‐GABA co‐transport. 8. By analysing the [Na+]o‐dependent suppression of GABA‐induced ICl, the stoichiometric ratio of the underlying co‐transport was estimated to be one: one Na+ ion per GABA molecule. 9. The ICl induced by GABA agonists such as beta‐alanine, taurine, l‐GABOB (l‐gamma‐amino‐beta‐hydroxybutyric acid) and muscimol was not affected by the amount of external Na+ present, suggesting difference in the affinity between receptor and transport carrier.

Cone-driven external H1 horizontal cells (H1 HCs) in the cyprinid fish retina hyperpolarize in response to all visible lights, and their synaptic inputs have been widely believed to be excitatory. Recent experiments indicate, however, that short- and long-?, (wavelength)-sensitive cone photoreceptors have different types of synaptic mechanisms; a conductance-decreasing, signreversing and short-?-mediating type, and a more conventional conductance-increasing class of excitatory (sign-conserving) synapse transmitting mainly long-? signals to H1 HCs. Here, a new set of evidence is presented for such spectrally segregated synaptic multiplicity, which also supports the notion that H1 HCs are actually color-opponent units where the depolarizing response component due to short-?-sensitive cones is normally overshadowed by the dominant hyperpolarizing component ascribed to long-?-mediating synaptic inputs. Application of dopamine to the retina preferentially enhanced the H1 HC responses to long-? flashes, and also depolarized the resting membrane potential in the dark. The spectral response was also examined after applying APB (2-amino-4-phosphonobutyric acid), in the presence of dopamine included to avoid polysynaptic effects of APB. This treatment enhanced the H1 HC responses to short-? stimuli and hyperpolarized the resting potential. These results are consistent with the suggestion that dopamine potentiates the conductance-increasing and long-?-mediating excitatory transmitter action, whereas APB acts as an agonist at the receptor involved in the conductance-decreasing and short-?-mediating transmitter action.

Vertebrate photoreceptors release neuro-transmitter substance(s) tonically in the dark and this release is curtailed by light. Recently, we have become increasingly aware of the possibility that short- and long-wavelength visual signals are mediated differently during the synaptic transmission to second-order retinal neurons. The experiment described here advances this notion further by demonstrating a postsynaptic difference. Treatment of the carp retina by dopamine reduced the gap-junctional coupling of horizontal cells, and we made use of this known effect to measure the input resistance (Rin) of H1-type horizontal cells. Flashes of light increased Rin. This increase, however, was found to be smaller with short wavelengths, even though the comparison was made when voltage responses were equal in amplitude. Often, Rin was even found to decrease at the blue end of spectrum. No single postsynaptic mechanism can account for any equal-voltage Rin difference such as this. The synaptic spectral segregation thus revealed is probably subserved by a dual scheme wherein the transmitter from blue-sensitive cone photoreceptors acts to decrease the membrane conductance of H1 cells whereas the synapses made by red-and green-sensitive cones are of a classical excitatory type.

A new scheme is described for radio transmission of multidimensional imagery data. The sender creates a nonlinear filter whose Wiener kernel is free to vary. The message pattern is mapped into the kernel. The filter is stimulated with a Gaussian white-noise input and the response is transmitted to the receiving end. Thus, the encoding algorithm is a convolutional operation. The white-noise input serves as a reference which may be also transmitted, or alternatively may be conveyed apriorito the intended receiver. The decoding algorithm for the message pattern to re-emerge is a multi-dimensional cross-correlation between the reference and the received response signal. The method keeps high tolerance to powerful extraneous noises including nonstationary disturbances such as periods of complete signal black-out. These holography-like features are discussed in the light of statistical error analysis of image recovery. The two-dimensional case is examined in greatest detail to demonstrate these performance advantages over the telephotographic procedures operating on a direct pixel-by-pixel basis.

1. Membrane currents produced by flashes and steps of light (photo‐current) were recorded from the ventral photoresponsive neurone of Aplysia californica. The effects of background illumination and changes in temperature were also examined. 2. The falling phase of the response wave form may be separated into two components with time constants of 10‐‐12 sec and 50 sec. 3. Background illumination reduced the response amplitude to light impulses without appreciably altering the response wave form. 4. Lowering the temperature greatly reduced the amplitude of the photo‐current with a Q10 of 2.91 (25‐‐15 degrees C) and greatly prolonged the duration of the response. 5. Because of the relatively large distance between the plasma membrane and the pigmented cytoplasmic lipochondria where light is absorbed, a diffusion‐based model with Ca as the internal‐transmitter (Andresen & Brown, 1979) was developed. 6. In this model diffusion of Ca2+ released from the lipochondria upon photon absorption is slowed by the reversible uptake of Ca2+ at cytoplasmic binding sites. Ca2+ interacts with sites at the plasma membrane to increase GK and Ca2+ levels are subsequently restored by irreversible uptake processes. Ca2+ release and its adsorption and desorption from the more numerous plasma membrane binding sites were assumed to be instantaneous with respect to the duration of the light‐evoked response. 7. The linearized model equations adequately predict the experimental response wave forms, the effects of temperature, and saturation of the steady‐state amplitude‐‐stimulus relationship. Aside from amplitude scaling, no curve‐fitting was used. 8. The model also gives realistic values for the cytoplasmic diffusion coefficient of Ca and the net rate of Ca efflux required to restore dark Ca activity.

Smooth pursuit and saccadic components of foveal visual tracking as well as more involuntary ocular movements of optokinetic (o.k.n.) and vestibular nystagmus slow phase components were investigated in man, with particular attention given to their possible input‐adaptive or predictive behaviour. Each component in question was isolated from the eye movement records through a computer‐aided procedure. The frequency response method was used with sinusoidal (predictable) and pseudo‐random (unpredictable) stimuli. When the target motion was pseudo‐random, the frequency response of pursuit eye movements revealed a large phase lead (up to about 90 degrees) at low stimulus frequencies. It is possible to interpret this result as a predictive effect, even though the stimulation was pseudo‐random and thus 'unpredictable'. The pseudo‐random‐input frequency response intrinsic to the saccadic system was estimated in an indirect way from the pursuit and composite (pursuit + saccade) frequency response data. The result was fitted well by a servo‐mechanism model, which has a simple anticipatory mechanism to compensate for the inherent neuromuscular saccadic delay by utilizing the retinal slip velocity signal. The o.k.n. slow phase also exhibited a predictive effect with sinusoidal inputs; however, pseudo‐random stimuli did not produce such phase lead as found in the pursuit case. The vestibular nystagmus slow phase showed no noticeable sign of prediction in the frequency range examined (0 approximately 0.7 Hz), in contrast to the results of the visually driven eye movements (i.e. saccade, pursuit and o.k.n. slow phase) at comparable stimulus frequencies.

The origin of the previously observed unusual photostability of 2,4,6-triisopropyl-4‘-(methoxycarbonyl)benzophenone (1-p-CO2Me) in the solid state was investigated. 1-p-CO2Me was found to photocyclize normally to produce the corresponding benzocyclobutenol 2-p-CO2Me when its solid-state photolysis was carried out either (a) after thorough grinding, (b) after solid−solid mixing with 2,4,6-triisopropyl-4‘-(ethoxycarbonyl)benzophenone (1-p-CO2Et), or (c) at elevated temperatures (an estimated energy barrier of 20 kcal/mol). Furthermore, when the photolysis was performed under more carefully deoxygenated conditions (closed argon atmosphere), formation of blue species that are persistent in the absence of oxygen was observed. On the basis of oxygen trapping and ESR experiments, the blue species are regarded as a mixture of a diradical intermediate DR and monoradicals derived thereof. The X-ray study of 1-p-CO2Me had revealed that the distances between the carbonyl oxygen and the o-i-Pr methine hydrogens are within the critical limit for hydrogen abstraction to occur, but a small reaction cavity or the compact crystal packing around both of the o-i-Pr groups is interfering with the photocyclization. The present results are consistent with this X-ray crystal structure; i.e., the photochemical hydrogen abstraction of 1-p-CO2Me to DR can take place, but DR reketonizes back to 1-p-CO2Me under the usual photolysis conditions because there is a high topochemical barrier to cyclization leading to 2-p-CO2Me.

Biliner systems driven by white Gaussin input are stuided in the light of the orthogonal functional expansion of Wiener. The Wener Kernels are drived analytically, and their structural properties are discussed in relationship with the differential equation that governs the billinear system. This should be useful for bilinear system indentification based on the multidimensional crosscorrelation method. A Wiener-series approach to stochastic design of bilinear systems is also presented, showing that the n-th order wiener kernel together with a parseval relation can be used to predict the mean square response of bilinear systems. An example is included, in which a bilinear servomechanism tracks a Brownian-motion target.

The dependence of the tensile strength of unidirectional carbon fiber/epoxy resin composite strand on the fiber-matrix interfacial shear strength was investigated. The interfacial shear strength was changed by applying different levels of liquid-phase oxidations to the carbon fibers. The tensile strength of the composite strands did not increase monotonically with increasing interfacial shear strength but showed a maximum at a certain level of the interfacial shear strength. The results were interpreted based on a fracture model which took account of accumulation of fiber fractures due to distribution of the fiber strength, stress transfer to the fibers via the interfacial shear stress, and multiple fracture of fibers due to stress concentration. It was shown that the decrease in the tensile strength of the composite strand at a larger interfacial shear strength is caused by the increase in the coefficient of a multiple fracture. The dependences of the multiple fracture on the interfacial shear strength and the matrix modulus were compared.

AbstractWe present a case of spinal cord sarcoidosis with a unique magnetic resonance imaging (MRI) finding. MRI of the cervical spine revealed an unusual lesion of low signal intensity on T2-weighted image at the core of the lesion surrounded by high signal intensity. Tl-weighted gadolinium enhanced image showed a high signal at the core lesion. Low signal intensity on T2-weighted image in the case was suggested to be due to hemosiderin deposition. Steroid therapy dramatically improved clinical symptoms with a marked reduction of peripheral T2 high intensity area and the core lesion size detected by gadolinium enhancement. [Neurol Res 1999; 21: 755-757]

A 13-year-old boy who suffered from Kawasaki disease at the age of 2 months underwent percutaneous transluminal coronary rotational ablation for coronary stenosis. After this procedure, coronary spasm occurred and he experienced acute myocardial infarction within 10 days. Total occlusion of the LAD was demonstrated by coronary angiography. Coronary spasm after such a procedure is one of the most dangerous complications causing acute myocardial infarction.

Bi-based perovskite-type oxide materials such as BiFeO3 (BFO) and the related compounds receive much attention and have been developed actively as important candidates for Pb-free ferroelectric / piezoelectric materials instead of toxic Pb-based perovskite oxide materials. Recently, many researches have been reported for thin films of BFO by various film-deposition techniques for actual application of semiconductive devices, microactuators, etc. In this report, we tried preferential crystal growth of BFO films on semiconductive silicon substrates using uniaxial-(100)-oriented LaNiO3 (LNO) buffer layer. BFO films were fabricated via chemical solution deposition (CSD) technique on platinized silicon wafer [(111)Pt/TiO2/(100)Si] and (100)LNO-coated platinized silicon [(100)LNO/(111)Pt/TiO2/(100)Si] substrates. XRD analysis indicated that the films fabricated on (111)Pt/TiO2/(100)Si substrate consisted of randomly-oriented BFO crystal with lower crystallinity and trace amount of the second Bi2Fe4O9 phase. On the other hand, the films on (100)LNO/(111)Pt/TiO2/(100)Si consisted of uniaxial-(100)-oriented BFO crystal with higher crystallinity. The crystallization temperature these films were 450 and 400degC, respectively. These results suggest that the BFO crystal was grown epitaxially on uniaxial oriented (100)LNO plane which also had perovskite-type crystal structure. Consequently, (100)-oriented BFO films were prepared on Si substrate successfully using (100)LNO buffer layer.

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