Stannum (IV) chloride stimulates vanadium (IV) catalyzed oxidation of NADH.

Stannum has been found to be an essential ultratrace element, however, the biological functions of stannum remain to be clarified. We found that stannum (IV) chloride stimulates vanadium (IV) catalyzed free radical chain oxidation of NADH. Stannum (IV) chloride, per se, did not catalyze the NADH oxidation. Superoxide, H2O2, and OH. are known to be the key species in vanadium catalyzed NADH oxidation. The inhibition of the vanadium (IV) catalyzed NADH oxidation in the presence of stannum (IV) chloride by catalase, superoxide dismutase (SOD), and hydroxyl radical scavengers indicated that the stannum (IV) chloride stimulated NADH oxidation consisted of almost the same reaction steps as that in the absence of stannum (IV) chloride. The results of inhibition studies on the NADH oxidation with SOD and catalase suggested that the reaction mixture containing stannum (IV) chloride contained a greater amount of H2O2 and a lower amount of O2- than that containing only vanadium (IV). Hydrogen peroxide is the precursor of OH. in the free radical chain reaction. The stimulation of NADH oxidation by stannum (IV) chloride is due to the stimulation of H atom abstraction by OH.. Stannum (IV) chloride might stimulate the generation of OH. by producing H2O2.

Purification and characterization of a new NAD(+)-dependent enzyme, L-tartrate decarboxylase, from Pseudomonas sp. group Ve-2.

A new enzyme, L-tartrate decarboxylase, was found in cells of Pseudomonas sp. group Ve-2. The enzyme was purified to homogeneity and characterized. The enzyme requires K+, Mg2+, and NAD+ for L-tartrate decarboxylation. The dependence of the enzymatic decarboxylation on NAD+ suggests that the decarboxylation involves redox reactions of the substrate. The enzyme catalyzes NAD(+)-linked oxidative decarboxylation of D-malate as well. The enzyme is composed of four subunits with identical molecular weight (Mr 40,000). The apparent Michaelis constants for L-tartrate and NAD+ are 1.1 mM, respectively. The cofactor requirements and the physical properties of the enzyme were similar to those of L-tartrate dehydrogenase-D-malate dehydrogenase from Rhodopseudomonas sphaeroides, and tartrate dehydrogenase from P. putida.

Developmental expression of cytochrome P450S within intrasplenically transplanted fetal hepatocytes.

Fetal hepatocytes were harvested at day 20 of gestation from spontaneously hypertensive rats (SHR) and then transplanted into recipient adult SHR spleens. Morphological examination of the recipient spleens revealed that, after 4 and 10 wk, large masses of hepatocytes were present in the red pulp with apparent cord-like structures. Larger batches of hepatocytes were observed in the spleens at 10 wk after than at 4 wk after transplantation. Of major significance was the fact that hepatocyte transplanted spleens were able to express several families of cytochrome P450 (cyto P450) proteins 2-10 wk after transplantation. Immunochemical determinations revealed that cytos P450 IA1, P450 IIB1, P450 p, P450 HLp, and P450 LA omega could be detected without any prior induction. All were intensely expressed 6 wk after transplantation; however, P450 IA1 and P450 IIB1 did not appear to be expressed by 2 wk after transplantation. Although cytos P450 p and P450 HLp did not appear to be expressed by 10 wk after transplantation, they were induced with dexamethasone at that time. Cyto P450 LA omega and peroxisomal acyl CoA oxidase were expressed 6 wk after transplantation in a 70% hepatectomized host. These results demonstrate that fetal hepatocytes can be successfully transplanted into the spleens of recipients and that the fetal hepatocytes appear to grow and develop cyto P450 metabolizing systems.

Global interactions in perceptual completion at the blind spot.

Nonlinearity and asymmetrical property in the filling-in process at the blind spot are investigated. Perceptual completion of a pattern with a gap is deteriorated, i.e. gap information inhibits completion across the gap. Filled-in patterns, observed from complementary patterns, are not the same in complementary sense. These suggest that perceptual completion cannot simply be predicted from a superimposition of completions, obtained from local stimulus conditions, and seems to be mediated by global processes.

Neural interactions of two moving patterns in the direction and orientation domain in the complex cells of cat's visual cortex.

An examination was made of the responses of complex cells in cat's striate cortex to a textured (nonoriented) stimulus moving in the preferred direction, superimposed upon either a textured or a grating stimulus (oriented) that was moved in different directions. The cell discharges elicited by the textured stimulus moving in the preferred direction were reduced by the textured stimulus moving in nonpreferred directions, and increased when moved in the preferred direction. A grating moving in nonpreferred directions showed similar inhibitory effects on the responses to a textured stimulus moving in the preferred direction. Neural processing for directional movement is, therefore, affected by other neural processing for directional movement, and still more by that for orientation.

Neural interactions of two slits in the orientation domain in the visual cortical units of the cat.

The responses of the cat's visual cortical cells to an optimally oriented (O-) and an inclined (theta-) slit have been studied. Cell's responses to the simultaneous presentation, in simple cells, are similar to those to theta-slit alone, but in complex cells, are remarkably decreased at orientation difference of about 45 degrees. In the sequential presentation, the effects of preceding theta-slit on the responses to the following O-slit decrease as the orientation difference increases. This suggests that neural interactions of simultaneous and sequential presentation of two slits are caused by different mechanisms.

Simultaneous determination of tegafur and 5-fluorouracil in serum by GLC using nitrogen-sensitive detection.

A sensitive assay of both tegafur (I) and 5-fluorouracil (5-FU) using GLC with a nitrogen-phosphorus-sensitive detector is described. The drugs were extracted from rabbit serum with ethyl acetate and methylated with diazomethane. Linearity was obtained over the concentration ranges of 3.13-200 micrograms/ml for I and 0.0313-2 micrograms/ml and 10-50 ng/ml for 5-FU. The detection limits of I and 5-FU in serum were 50 and 8 ng/ml, respectively. The serum concentrations of the drugs determined by the present method closely agreed with those obtained by spectrophotometry for I and microbial assay for 5-FU.

Intake ratio of water-insoluble dietary fiber to the water-soluble one in Japanese: an estimation on dietary records and the secular consideration on the national nutrition survey.

Thirty-four foods were analyzed in order to determine the content of water-soluble dietary fiber (SDF) and insoluble dietary fiber (IDF). Using the results with the standard table for 227 foods, the intake ratio of IDF/SDF of an average Japanese was calculated for the period 1946-1990. The ratio was 3.22 in 1990 as calculated on the food intakes shown in the national nutrition survey, and the secular change was not detected since 1946 when the ratio was 3.30. The ratio was also shown to be well preserved between types of households including the age of the head. Using dietary records of 60 healthy city workers (average 42.8 years) for 4 weeks, however, the weekly average ratio for an individual was found to vary in the range of 2.25-5.13 although the total average for 60 individuals was 3.33. Thus, the well preserved IDF/SDF intake ratio for an average Japanese showed, on the contrary, a wide variation of food selection between each person.

[Use of Caco-2 cells for isolation of influenza virus].

In this study we assessed the usefulness of Caco-2 cells, derived from a human colon carcinoma, to isolate an influenza virus. Throat washings collected from 30 patients with influenza-like illnesses in Miyazaki Prefecture in 1997 were inoculated in MDCK and Caco-2 cells, 17 influenza virus strains were isolated in MDCK cells, and 20 in Caco-2 cells. Of all the viruses isolated, only one strain was identified as influenza virus type B; other strains were identified as type A (H3N2). Furthermore, some influenza viruses were isolated in Caco-2 cells also from the specimens collected between 1991 and 1997. With Caco-2 cells, each type of influenza virus was isolated effectively without the supplement of trypsin in the culture medium. These facts indicate the usefulness of Caco-2 cells as a host to isolate influenza virus as shown to be suitable in the detection of many types of enteric viruses. Caco-2 cells will serve as a useful cell line for the surveillance of infectious disease because Caco-2 cells are sensitive to a wide range of virus.

[Detection of enterovirus 70 in acute hemorrhagic conjunctivitis by PCR-stringent microplate hybridization method].

The surveillance of acute hemorrhagic conjunctivitis (AHC) caused by enterovirus 70 (EV70) is insufficient because of the difficulties of virus isolation using conventional methods. In this study, reverse transcription-polymerase chain reaction (RT-PCR) and stringent microplate hybridization (SMH) methods were assessed for the detection of EV70 in conjunctival swabs collected from the patients of AHC which broke out in Miyazaki Prefecture in 1990 and Okinawa Prefecture in 1994. Furthermore, with the use of the SMH method, we compared the genetic homogeneity of EV70 detected from the samples collected in 1990 and 1994 to the J670/71 strain isolated approximately 25 years ago. A similar investigation was performed between recent coxsackievirus A24 variant (CA24v) and EH24/70 strain, a standard strain of CA24v that was isolated approximately 25 years ago. As a result, RT-PCR products were detected in 26 of 34 conjunctival swabs collected in Miyazaki Prefecture in 1990. Likewise, RT-PCR products were detected in 9 of 10 conjunctival swabs collected in Okinawa Prefecture in 1994, and these RT-PCR products were all identified as EV70 by SMH method. Such a high level of virus recovery from specimen shows the evidence of usefulness of these techniques. Recent EV70 showed a reaction of about 60% to a probe synthesized with J670/71. Likewise, recent CA24v showed a reaction of about 30% to a probe synthesized with EH24/70. These finding are highly suggestive of the progress of viral mutation.

[Antigenic types of Rickettsia tsutsugamushi isolated from patients with tsutsugamushi fever and their distribution in Miyazaki Prefecture].

Rickettsia tsutsugamushi (Rt) isolated from patients with tsutsugamushi fever were examined for their antigenicity. This was done by indirect immunofluorescence (IIF) with guinea pig antisera against three standard strains (Karp, Kato and Gilliam) and two local strains (Kawasaki and Kuroki) isolated in 1981, and with mouse monoclonal antibodies against the three standard strains. In the meantime, antibodies in sera from 317 out of 442 patients registered during 1985 to 1988 were titrated by IIF with those five Rt strains. 1) Local isolates, Kawasaki and Kuroki strains, reacted most effectively with the homologous antiserum, respectively, showing four fold lower IIF titers against the heterologous antisera. 2) Kawasaki strain reacted with none of the monoclonal antibodies, whereas Kuroki strain showed a slight reaction with anti-Karp and anti-Kato, but not anti-Gilliam, monoclonal antibodies. 3) Seventeen out of 27 strains isolated in 1985 resembled the Kawasaki strain in their reaction patterns with the antisera and monoclonal antibodies, and the other 10 strains showed reactivity similar to the Kuroki strain. 4) Sera of 233 (74%) out of 317 patients showed the highest antibody titers against the Kawasaki strain and 69 (22%) of 317 against the Kuroki strain. It is thus evident that Kawasaki and Kuroki strains are antigenically different from the standard strains, and Kawasaki and Kuroki strains also differ from each other. It is suggested that two antigenic types (Kawasaki and Kuroki) of Rt were distributed in Miyazaki Prefecture, Rt of the Kawasaki type slightly dominates Rt of the Kuroki type, and recent tsutsugamushi fever has been caused by either one or the other type of Rt.

Three-dimensional interpretation of quadrilaterals.

The three-dimensional interpretation of two-dimensional images was studied by using quadrilateral patterns, and some relationships between their structure, depth, and shape interpretations were analyzed under various viewing conditions. We defined rectangular and nonrectangular viewing conditions as follows: the viewing condition in which the quadrilateral, including parallel sides, could be a projection from a rectangle and the viewing condition in which it could not be so. For 9 subjects, 10 measurements were made in each experiment. Analysis showed that a pair of parallel sides of a quadrilateral were viewed as parallel to the viewer's forehead when the sides were horizontal in the image plane and were seen as slanting in depth if they were slanted in the image plane. The quadrilateral composed of parallel and nonparallel sides was perceived as rectangular when viewed with foveal vision even though under the nonrectangular viewing condition, if that viewing condition was not so different from the rectangular viewing condition. The quadrilateral did not appear to be rectangular when viewed in peripheral vision even though the rectangular viewing condition was used.

Transformation of visual neural signals into psychological information.

A theory is proposed which transforms visual neural signals into the psychological information and which explains visual illusions. As an example, Poggendorff's illusion is explained.

Visual information processing at the blind spot.

The perceptual completion at the blind spot was studied by presenting test patterns around the blind area of 3 subjects with normal acuity, and conditions generating the perceptual completion were investigated. To be filled in, a stimulus must fall on at least two quadrants around the blind spot. Both a region between 3.0 and 3.9 degrees in radii around the blind spot, which can generate white homogeneous completion, and the region between 4.3 and 5.2 degrees, which can not generate any completion solely, play important parts in provoking completion. Periodic stimuli were more effective than non-periodic ones.

Depth perception in simple line drawings.

Three-dimensional interpretation of simple line drawings, composed of two triangles with a common side, was studied through the quantitative measurement of perceived orientation of the surface indicated by a stimulus figure. In a single triangle, depth perception is ambiguous and is not stable even if perceived. In two triangles with a common side, however, depth is stably perceived. Depth effect, defined as the magnitude of the angle formed by the two perceived surfaces, increased linearly as the magnitude of an angle at a vertex facing the common side became larger. The depth effect did not vary significantly for the change of a triangular from when the magnitude of the angle at the vertex facing the common side was constant. These results suggest that the depth effect changes systematically with variation in the triangle's form.

[A study on serum level and urinary excretion of fosfomycin-Na in man with special reference to pharmacokinetic analysis (author's transl)].

FOM-Na was investigated on its distribution after a continuous intravenous drip infusion in 3 healthy adult volunteers, and its serum levels and urinary excretion were pharmacokinetically analyzed, while the excreted substance into urine was also analyzed with GC/MS. The results obtained are summarized as follows: 1. The distribution volume of FOM-Na in one-compartment open model was 0.183 L/kg, half life in human body 1.66 hours and renal clearance 0.0737 L/hr/kg. 2. With these pharmacokinetic constants, the mean values following various doses demonstrated almost equal irrespective of its dosage schedule, keeping an almost constant level in each individual tested. 3. The area under serum level-time curve was approximately 216 microgram.hr/ml per 1 g (potency), and increased in proportion to an infused dose within the range of 1 approximately 6 g (potency). Three consecutive administrations showed no trend of accumulation of the agent in the serum. 4. Urinary excretion of the agent was found to be very fast, and its recovery rate from urine within 10 approximately 11 hours after the completion of an i. v. drip infusion was approximately 95 approximately 99%. 5. As a result of GC/MS on the substance excreted into urine, it was noted that FOM-Na was not metabolized in human body and excreted into urine in its original form. 6. There was seen no specific change in electrocardiogram during and/or after an intravenous drip infusion in 1 hour of 2 g (potency) FOM-Na dissolved in a 300 ml 5% glucose solution.