[Several properties of a newly developed light-cured anterior restorative composite resin "Graft LC"]

A newly developed light-cured anterior restorative composite resin "Graft LC" by GC Co. is characterized by having Vita VMK 68 shades and containing glass filler particles treated with graft binders. Several properties of the resin were examined by using the SEM, surface recorder, and color analyzer. The Graft LC resin was classified as semi-hybrid resin. The filler particles of Graft LC resin comprised two kinds of glass filler in which Si, Ba and Al, and Si were detected. Graft LC resin showed a relatively small surface roughness after polishing in spite of the semi-hybrid resin. According to the degradation test in the alkaline solution, the polished surfaces of Graft LC resin became rough and the depth of subsurface damage layer increased with time. However, the filler particles were retained in the subsurface damage layers. An Ar ion etching employed for SEM preparation is useful to observe the subsurface damage layer distinctly under the SEM. No color change was found even after long-term immersion in a distilled water, though the color of Graft LC resin changed greatly due to irradiation.

GaAs/AlGaAs optical synaptic interconnection device for neural networks

A GaAs/AlGaAs optical synaptic interconnection device for neural networks is reported for the first time to our knowledge. This device consists of a light-emitting-diode array, an interconnection matrix, and a photodiode array, which are integrated into a hybrid-layered structure on a GaAs substrate. The device structure and characteristics are reported in detail. The fabricated device can simulate a 32-neuron system. Experimental results of the Hopfield associative memory with three stored vectors are also described.

[Clinical trial of T-3262 on acute enteritis. Japan Research Committee of T-3262, Research Group for Acute Infectious Enteritis]

For the purpose of evaluation of clinical efficacy, safety and usefulness on acute infectious enteritis (bacillary dysentery, and enteritis caused by Salmonella spp., Campylobacter spp., enteropathogenic E. coli, and so on), T-3262, a newly developed pyridone-carboxylic acid derivative, was administered to a total of 136 patients and carriers. In addition, in vitro antibacterial activity of T-3262 was determined against the clinical isolates, and compared with those of nalidixic acid (NA), pipemidic acid (PPA), enoxacin (ENX), norfloxacin (NFLX) and ofloxacin (OFLX). The daily dose of 450 mg of T-3262 was administered orally three times after meals for 5 days, with the exception of 7 day administration against Salmonella enteritis. A total of 89 cases were evaluated; 23 with Shigella spp., 30 with Salmonella spp., 15 with Campylobacter spp., 6 with enteropathogenic E. coli, and 15 cases with the other pathogens or pathogen-negative. The efficacy on clinical symptoms judging from duration of fever, and duration of diarrhea and abnormal stool character was 100% in all the enteritis except enteropathogenic E. coli enteritis, in which it was 50% (n = 2). Concerning bacteriological response, elimination of the causative organisms from the feces was 100% in Shigella spp. (n = 19), Salmonella spp. (n = 30), and enteropathogenic E. coli (n = 6), although 64.3% in Campylobacter spp. (n = 14). As an adverse effect, epigastric discomfort was observed in one (0.8%) of 130 cases. Deteriorations in laboratory findings were seen in five (6.2%) of 81 cases, consisting of two with elevated GOT and GPT, two with elevated GPT, and one with increased eosinophils count, although they were all slight in degree. MICs of T-3262 which inhibited 90% of the isolates of Shigella spp, Salmonella spp., and Campylobacter spp., were 0.025, 0.05, and 0.78 microgram/ml, respectively. These values were lowest among the quinolone derivatives tested, except that the MIC90 against Campylobacter spp. was the same as that of ofloxacin.

[Comparison of clinical efficacy of lomefloxacin (LFLX, NY-198) and pipemidic acid (PPA) in the treatment of infectious enteritis by a double-blind method. The Japan Research Committee of Lomefloxacin Research Group Enteritis]

The clinical efficacy, safety and usefulness of lomefloxacin (LFLX, NY-198), a new quinolone antimicrobial agent, were compared with those of pipemidic acid (PPA) in the treatment of infectious enteritis (bacillary dysentery, enteropathogenic Escherichia coli enteritis and Campylobacter enteritis) by a double blind method. Daily dosage of LFLX and PPA was 600 mg and 2000 mg, respectively administered orally divided into 4 doses. The duration of the treatment was 5 days. Of 290 cases studied, 100 cases were excluded and 21 cases were dropped from analysis of effectiveness and usefulness. The effectiveness and usefulness was evaluated in 169 cases (LFLX group: 83, PPA group: 86). There was no significance difference between the two groups in any background characteristics. The results obtained were as follows: 1. In 73 symptomatic patients (LFLX group: 35, PPA group: 38) on the day of the beginning of administration, the clinical effect was 91.4% in the LFLX group and 84.2% in the PPA group with no significant difference between the two groups. 2. In a total of 184 strains (LFLX group: 90, PPA group: 94), the bacteriological effects of LFLX (93.3%) was superior to that of PPA (80.9%) with significant difference (p = 0.0153). 3. In 169 evaluable patients, the global clinical effects of LFLX (92.8%) was superior to that of PPA (79.1%) with a significant difference (P = 0.0144). 4. Side effects were observed in 1 (0.7%) of the 141 patients in the LFLX group and none of the 143 patients in the PPA group. Abnormal laboratory test values were noted in 10 (7.6%) of the 132 patients treated with FLLX and 7 (5.1%) of the 136 patients treated with PPA, but they as no significant difference between the two groups. 5. In 169 evaluable patients, the clinical usefulness of LFLX (91.6%) was superior to that of PPA (76.7%) with a significant difference (P = 0.0111). From these results, LFLX is considered to be a clinically useful medicine in the treatment of infectious enteritis including bacillary dysentery.

Unstable expression of E-cadherin adhesion molecules in metastatic ovarian tumor cells

E-Cadherin is a member of the cadherin family, which plays a key role in intercellular adhesion in various tumors as well as in normal tissues. Here, we examined the expression of this adhesion molecule in a murine ovarian tumor line OV2944, whose sublines show different degrees of spontaneous metastasis from subcutaneous sites; sublines LM-1 and LM-3 exhibit a low metastatic activity but a variant subline HM-1 has a high metastatic activity. When the expression of E-cadherin in these cells was examined by immunoblot analysis, the highly metastatic HM-1 cells was found to express an extremely small amount of this molecule, as compared with a high level of E-cadherin expression in the weakly metastatic LM-1 and LM-3 cells. Northern blot analysis showed that the amount of tanscripts from the E-cadherin gene is proportional to the amount of proteins detected in these cells. Immunofluorescence staining revealed that cells of the highly metastatic line were heterogeneous, that is, their cultures contained both E-cadherin-positive and negative cells. In contrast, cells of the weakly metastatic lines homogeneously expressed E-cadherin. When the highly metastatic line was subcloned, all the subclones consisted of E-cadherin-positive and negative cells. These results suggest that the expression of E-cadherin gene is not stably controlled in the highly metastatic line.

Identification of glutamic acid 186 affinity-labeled by 2,3-epoxypropyl alpha-D-glucopyranoside in soybean beta-amylase

Soybean beta-amylase was modified with 2,3-epoxypropyl alpha-D-[U-14C]glucopyranoside ([14C]alpha-EPG), a radioactive affinity-labeling reagent for beta-amylase, until it lost 95% of its enzyme activity. After S-carboxymethylation at pH 8.0 of SH groups, the modified enzyme was digested at pH 7.0 with Achromobacter protease I and the digest was fractionated by reverse-phase HPLC. A radioactive peptide was finally isolated and its amino acid sequence was determined to be 181Leu-Gly-Pro-Ala-Gly-Glu186. Radioactivity derived from [14C]-alpha-EPG was found exclusively at Glu-186, the gamma-carboxyl group of which is esterified with the affinity label. It was concluded that the carboxylate of Glu-186 is a functional group at the catalytic site of soybean beta-amylase.

Neonatal lupus syndrome and microtubular structure

A female infant, at 6 weeks old, with the clinical manifestation of annular erythemas on the trunk and face, was positive for anti-SS-A and anti-SS-B antibodies. The annular erythema disappeared spontaneously at the age of 7 months when anti-SS-A and anti-SS-B antibodies were negative. Electron microscopic observation of the vascular endothelial cells on the annular erythema revealed microtubular structures. Later microtubular structures were found absent from the vascular endothelial cells of the area where the annular erythema had disappeared. The patient's mother is suffering from Sjögren's syndrome; she has no clinical symptoms but anti-SS-A and anti-SS-B antibodies are positive and a biopsy of small salivary glands of the lip demonstrated a marked periductal mononuclear cell infiltration. Microtubular structures were observed in her vascular endothelial cells in the small salivary gland region. These findings suggest that disappearance of microtubular structure may have some relationship with anti-SS-A and anti-SS-B antibodies.

Energetics of alpha-chymotrypsin-mediated hydrolysis of a strained cyclic ester

Hydrolysis of omicron-hydroxy-alpha-toluenesulfonic acid sultone (sultone II) is mediated by alpha-chymotrypsin. Sultone II is a highly strained cyclic ester substrate that forms a covalent intermediate with the enzyme and is therefore expected to release ring-strain energy upon formation of the sulfonyl enzyme species. It is found that the equilibrium constant for forming the covalent intermediate from the Michaelis complex is quite modest (K2 = 16.4), suggesting that perhaps the strain energy is not released in the ring-cleavage event. The implied retention of chemical (strain) energy by the sulfonyl enzyme species raises the question of the means by which the enzyme avoids expression of strain energy and the implications of this effect in the catalytic sequence. High-pressure liquid chromatography (HPLC) rate data demonstrate facile reversion of sulfonyl enzyme to the Michaelis complex, and that reversion is preferred over hydrolysis of the covalent intermediate. pH-independent rate and equilibrium constants are derived for the alpha-chymotrypsin-mediated hydrolysis of sultone II, and pKa values for groups on the enzyme are reported that are consistent with literature values obtained from analysis of nonspecific substrate hydrolysis by the enzyme.

Affinity labeling of soybean beta-amylase with 2',3'-epoxypropyl alpha-D-glucopyranoside

The synthesized 2',3'-epoxypropyl alpha-D-glucopyranoside (alpha-EPG) inactivated soybean beta-amylase completely. The incorporation of alpha-EPG into the enzyme at 92% inactivation was 1.1 mol per mol of enzyme, as determined by using 14C-labeled alpha-EPG. The inactivation obeyed saturation kinetics of a two-step mechanism. The dissociation constant of alpha-EPG-enzyme complex and the rate constant of the irreversible inactivation step were estimated to be 119 mM and 1.14 X 10(-3)s-1, respectively. alpha-Cyclodextrin, a competitive inhibitor of this enzyme, protected the enzyme against the inactivation by alpha-EPG in a competitive manner. This suggests that alpha-EPG binds to the active site of the enzyme. The above results indicate that alpha-EPG acts on soybean beta-amylase as an affinity labeling reagent. It was also shown that an essential SH group near the active site, but not the catalytic one, scarcely participated in the inactivation by alpha-EPG.

[Computerized single probe system using a cadmium telluride detector]

Using cadmium telluride (CdTe) as a detector, we assembled a computerized single probe system. The size of the CdTe used is 16 mm in diameter and 2 mm in thickness. Two types of the straight bore collimators of 16 mm in diameter were prepared. One is 16 mm in length (long type) and the other is 5 mm in length (short type). The response curves of the long and short type collimators to 57Co in water showed that the points at 10% of maximum counts were 4 cm and 3 cm in depth along the center axis. The data were accumulated by using a commercialized single cardiac probe system (OMNISCOPE) and processed by itself or transferred to the microcomputer (LSI-11/23) for further analysis. Twenty percent count loss occurred at 100 000 cps with an integral discriminator setting. This system was applied for cerebrospinal fluid (CSF) shunt flow evaluation and measurement of left ventricular ejection fraction (LVEF). Measurement of CSF shunt flow has been able to do in any patient's positioning. In 21 patients with various heart diseases, LVEFs obtained by CdTe detector were compared with those obtained by scintillation detector. There was good correlation between the LVEFs obtained by these two detectors: correlation coefficient (r)=0.939.

[Double-blind comparative clinical evaluation of cefamandole and cefmetazole in the treatment of respiratory tract infections]

Cefamandole sodium (CMD), a new cephalosporin-derivative, was synthesized in the Laboratory of Eli-Lilly Co. Ltd. U.S.A. in 1972. CMD, which is several times more active than cefmetazole (CMZ, a cephamycin antibiotic) against Gram-positive cocci, is only as active as the latter antibiotic against Gram-negative bacilli. Against Haemophilus influenzae, CMD exhibits an antimicrobial activity which is as strong as that of ampicillin sodium. Our previous comparative tests on efficacy and safety of CMD versus cefazolin (CEZ) demonstrated that CMD was as effective and safe as CEZ in the treatment of respiratory tract infections. In the present clinical trial, the efficacy and safety of CMD are evaluated by a comparative double blind method using CMZ, a more recently synthesized cephamycin antibiotic, as a reference drug. For this purpose, a comparative double blind study was carried out in 50 institutions and clinics in Tohoku and Hokkaido districts in Japan. A total of 272 inpatients, who was aged over 16 years and was diagnosed as having pneumonia, lung abscess or acute infectious exacerbation of chronic obstructive pulmonary diseases, was included in this trial. They received 2 g of CMD or CMZ twice a day by intravenous drip infusions, as a rule, for 14 days. Of these patients, 264 (133 received CMD and 131 CMZ) were available for the evaluation of safety and usefulness. Two hundred and thirty-eight patients (122 received CMD and 116 CMZ) were adopted for the evaluation of efficacy. Prior to the treatment, there was no significant difference with respect to age, sex, severity of infection and underlying diseases between subjects in 2 treatment groups. An excellent or good clinical response was obtained in 82% of the patients treated with CMD, and in 81% of those treated with CMZ. Thus, there was no significant difference in cure rate between 2 treatment groups. However, an excellent clinical response was found in 12.3% of the patients treated with CMD, whereas only in 4.3% of those treated with CMZ. This difference in percentage of excellent clinical response between 2 treatment groups was statistically significant (P less than 0.05). Of the 87 patients with moderate to severe infection who were treated with CMD, 13 showed an excellent response. Only 4 of 90 patients treated with CMZ showed an excellent response. Statistically the difference in the rate of excellent response between these 2 groups was significant (P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

Difference spectroscopic study of the interaction between soybean beta-amylase and substrate or substrate analogues

1. In order to investigate the interactions between soybean beta-amylase [EC 3.2.1.2] and ligands (maltotriose as substrate, and maltose and alpha- and beta-cyclodextrins as inhibitors for the hydrolysis of maltoheptaose), the difference spectra were measured at 25 degrees C and pH 5.4, in 0.05 M acetate buffer. Each difference spectrum produced by these ligands showed a clear peak at 292-293 nm due to a tryptophan residue. In addition to this peak, the spectra of alpha- and beta-cyclodextrins showed a specific peak at 298-299 nm, and that of maltotriose showed a shoulder at 298 nm. 2. From the concentration dependency of the difference molar extinction delta epsilon, at 292-293 nm or at 298-299 nm, the dissociation constant of the enzyme-ligand complex, Kd, was evaluated for maltotriose, and alpha- and beta-cyclodextrins. For each ligand, the Kd values obtained at these two wavelengths were in good agreement with Michaelis constant, Km, or the inhibitor constant, Ki. The Kd value for maltose obtained from the titration of delta epsilon at 292 nm was also in good agreement with Ki. 3. Maltose produced a hydrophobic change in the environment of the tryptophan residue, while the interactions of maltotriose, and alpha- and beta-cyclodextrins with this enzyme caused an electrostatic change in the vicinity of the tryptophan residue in addition to the hydrophobic change. Since the signal at 298-299 nm was not found in the difference spectrum of maltose, this signal may be due to a tryptophan residue different from that which produces the signal at 292-293 nm. If both the signals are due to the same tryptophan residue, we must conclude that some conformational change is caused in the enzyme active site by the ligand binding.

Kinetic study on chemical modification of Taka-amylase A. II. Ethoxycarbonylation of histidine residues

The modification of Taka-amylase A (TAA) [EC 3.2.1.1] of Aspergillus oryzae by diethylpyrocarbonate (DEP) was carried out at 25 degrees C and at pH 5.8 (0.1 M acetate buffer). Two out of the six histidine residues were modified with 4.6 mM DEP, and two or three histidine residues were modified with 23 mM DEP. In both cases, one of them was protected from modification by the presence of 15% maltose. The results suggest that two or three out of the six histidine residues are exposed on the surface of the TAA molecule, and one of them exists near the maltose binding site. Ethoxycarbonylation of histidine residues of TAA caused loss of the amylase activity and activation of the hydrolysis of phenyl alpha-maltoside (phi alpha M). The kinetic parameters of the modified TAA for several substrates and analogs were determined at 25 degrees C and at pH 5.3 (0.08 M acetate buffer). From the results, it was found that this alteration of the enzyme activity by the modification was not due to a change in Km value but to a change in k0 value. Thus, some of the histidine residues in TAA are suggested to play an important role in the enzyme catalytic function.

Kinetic study on chemical modification of taka-amylase A. I. Location and role of tryptophan residues

1. Five and four tryptophan residues in Taka-amylase A [EC 3.2.1.1] of A. oryzae (TAA) were modified with dimethyl(2-hydroxy-5-nitrobenzyl)-sulfonium bromide (K-IWS) in the absence and the presence of 15% maltose (substrate analog), respectively. Only one tryptophan residue was modified with dimethyl(2-methoxy-5-nitrobenzyl)-sulfonium bromide (K-IIWS) irrespective of the presence or absence of maltose. Kinetic parameters (molecular activity, k0, Michaelis constant, Km, and inhibitor constant, Ki) of the enzyme modified with K-IWS and K-IIWS were determined. The k0 value decreased with increase in the number of modified residues, but Km and Ki values and the type of inhibition were not altered by the modification. 2. The fluorescence quenching reaction of TAA with N-bromosuccinimide (NBS) proceeded in three phases. The second-order rate constants of the three phases were determined to be (4.3 +/- 0.5) x 10(5) M-1 . s-1, (2.1 +/- 0.3) x 10(3) M-1 . s-1 and (1.7 +/- 0.2) x 10(2) M-1 . s-1, respectively. In the presence of maltose, the first phase was further separated into two phases with rate constants of (4.6 +/- 0.6) x 10(6) M-1 . s-1 and (6.9 +/- 1.1) x 10(4) M-1 . s-1, respectively. On the basis of the results, it is estimated that five out of nine tryptophan residues are accessible to the solvent and among them, two tryptophan residues are substantially exposed: one is located in the maltose binding site near the catalytic site (its modification affects the catalytic function), and the other exists on the enzyme surface far from the active site.