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A Saito

Publications and source records attributed to A Saito.

At least 19 recordsLinked to original sources
PubMed1992

Three-dimensional solution structure of the B domain of staphylococcal protein A: comparisons of the solution and crystal structures.

The three-dimensional solution structure of the recombinant B domain (FB) of staphylococcal protein A, which specifically binds to the Fc portion of immunoglobulin G, was determined by NMR spectroscopy and hybrid distance geometry-dynamical simulated annealing calculations. On the basis of 692 experimental constraints including 587 distance constraints obtained from the nuclear Overhauser effect (NOE), 57 torsion angle (phi, chi 1) constraints, and 48 constraints associated with 24 hydrogen bonds, a total of 10 converged structures of FB were obtained. The atomic root mean square difference among the 10 converged structures is 0.52 +/- 0.10 A for the backbone atoms and 0.98 +/- 0.08 A for all heavy atoms (excluding the N-terminal segment from Thr1 to Glu9 and the C-terminal segment from Gln56 to Ala60, which are partially disordered). FB is composed of a bundle of three alpha-helices, i.e., helix I (Gln10-His19), helix II (Glu25-Asp37), and helix III (Ser42-Ala55). Helix II and helix III are antiparallel to each other, whereas the long axis of helix I is tilted at an angle of about 30 degrees with respect to those of helix II and helix III. Most of the hydrophobic residues of FB are buried in the interior of the bundle of the three helices. It is suggested that the buried hydrophobic residues form a hydrophobic core, contributing to the stability of FB.(ABSTRACT TRUNCATED AT 250 WORDS)

Amides↗
PubMed1992

Inositol polyphosphate receptor and clathrin assembly protein AP-2 are related proteins that form potassium-selective ion channels in planar lipid bilayers.

We have previously described an inositol polyphosphate receptor (IPxRec), purified from detergent-solubilized bovine cerebellum microsomes, that displays potassium ion channel activity in planar lipid bilayers. We now find that the IPxRec is closely related to clathrin assembly protein AP-2. The IPxRec and AP-2 purified from bovine brain clathrin-coated vesicles share several structural and functional features: (i) similar subunit composition; each has four major polypeptides that have similar mobility (Mr values of 111,000, 100,000, 50,000, and 17,000) and relative intensity by SDS/PAGE analysis; (ii) similar size as studied by molecular sieve chromatography (Mr 400,000); (iii) identical N-terminal amino acid sequences for the Mr 50,000 subunits and Mr 111,000/100,000 doublets; (iv) immunoreactivity of the AP-2 Mr 111,000/100,000 doublet to polyclonal antibodies affinity purified against the doublet proteins of the IPxRec; (v) display of the in vitro diagnostic feature of assembly proteins--i.e., they induce the assembly of clathrin cages; and (vi) ion channel activity selective for potassium ions with the same unitary conductance when incorporated into planar lipid bilayers. One difference was found. AP-2 channels were not blocked by inositol 1,3,4,5-tetraphosphate as reported for IPx receptor channels. These studies suggest a possible connection between the IPx signaling pathways and receptor-mediated endocytosis.

Adaptor Proteins, Vesicular Transport↗
PubMed1992

Cloning and expression of rat preproendothelin-3 cDNA.

We report here the cloning and expression of a rat full-length cDNA encoding preproendothelin-3 (preproET-3). The predicted rat preproET-3 consisted of 167 amino acid residues. As in other ET-family peptides, the mature rat ET-3 was predicted to be produced through unusual processing from a 41-residue intermediate, the big ET-3 in rat. Transient transfection of COS-7 cells with the cloned preproET-3 cDNA resulted in the production of mature ET-3 and this production was inhibited by phosphoramidon, a metaloprotease inhibitor. This suggested that a phosphoramidon sensitive mechanism was involved in the production of ET-3 in the transfected COS-7 cells. Northern blot analysis showed that an approximately 3.0-kb rat preproET-3 mRNA was expressed in rat tissues, including the eye ball, submandibular gland, brain, kidney, jejunum, stomach and spleen. A 2.0-kb and a 3.3-kb mRNA were also detected in the eye ball and small intestine, respectively. The distinct distribution of rat preproET-3 mRNA from that of preproET-1 mRNA suggested that ET-1 and ET-3 played different roles.

Amino Acid Sequence↗
PubMed1992

Structural and functional characterization of an inositol polyphosphate receptor from cerebellum.

An inositol polyphosphate receptor has been purified from bovine cerebellum which consists of three different polypeptides with Mr of 111,000, 102,000, and 52,000. Negative staining electron microscopy reveals globular-like structures 10-13 nm in diameter. The receptor has a Stokes radius of 400,000 daltons as determined by molecular sieve high performance liquid chromatography. The receptor preparation binds inositol 1,3,4,5-tetrakisphosphate, inositol hexaphosphate (or phytol), and inositol 1,4,5-trisphosphate (IP4, IP6, and IP3, respectively) with submicromolar affinity (0.19, 0.15, and 0.54 microM, respectively) at conditions approximating physiological ionic strength and pH. The purified receptor preparation, when reconstituted into planar bilayers, displays ion channel activity, preferentially permeable to K+. Permeability ratios of the channel are PK+/PNa+ approximately 5 and PK+/PCl approximately 19. In symmetrical 100 mM KCl, the channel is characterized by long open times (minutes) with a conductance of 7.2 picosiemens. The channel is selectively modulated by IP4. That is, at 1 microM IP4, the mean open time decreased substantially to rapid flicker behavior and the channel is completely closed at 10 microM IP4. IP6 and IP3 did not modulate the channel under similar conditions. Thus, the channel appears to be an IP4-modulated K+ channel.

Animals↗
PubMed1992

Long-distance restriction mapping of the proximal long arm of human chromosome 21 with Not I linking clones.

Human chromosome 21 is the smallest of the 22 autosomes and 2 sex chromosomes. Hybridization of the human repetitive sequence Alu to pulsed-field gel-fractionated Not I-digested genomic DNA from a human-mouse hybrid cell line containing chromosome 21 as the sole human component identified chromosome 21 Not I restriction fragments. A Not I restriction map of regions of the chromosome was constructed, by identifying neighboring Alu bands with Not I linking clones. This approach simplifies the task of physical mapping and avoids ambiguities in Not I fragment assignments that arise from gel-to-gel mobility variations. A contiguous map was constructed with six Not I linking clones that covers at least the proximal one-third of the long arm of chromosome 21 and spans 20 megabases. A more detailed restriction map revealed 11 likely CpG islands in this region and localized 11 additional DNA markers.

Chromosomes, Human, Pair 21↗
PubMed1992

Heterogeneity in gastric carcinoma with special reference to DNA content and mitotic activity: histopathologic differentiation.

DNA ploidy and mitotic activity were microspectrophotometrically investigated in 46 patients with gastric carcinoma. Measurements of DNA content and mitotic index (M.I.) were examined in the mucosal, submucosal, muscularis propria, and serosal layers of tumors, respectively. The frequency of cells with values exceeding hexaploid chromosome (6c) and mitotic counting analysis revealed a significant higher value in serosa, compared with findings in the mucosa. This tendency was not evident in cases of a differentiated type adenocarcinoma but was noted in those with the undifferentiated type. There were 37 tumors (80.0%) with the same DNA distribution patterns in every layer of the stomach (homogeneous DNA ploidy). Heterogeneity of DNA ploidy was observed in nine tumors (20.0%). Carcinoma with a heterogeneous DNA ploidy manifested a significantly higher incidence of metastasis to the lymph nodes than did those with homogeneous type. Characteristically, there was venous permeation preponderance in the differentiated type and peritoneal dissemination preponderance in the undifferentiated type. This evidence of DNA heterogeneity in gastric carcinoma tissues suggests a possible correlation with the metastatic behavior.

Cytophotometry↗
PubMed1992

In vitro succinate dehydrogenase chemosensitivity of gastric carcinoma--relationship to DNA content.

Relationships between in vitro chemosensitivity and cell nuclear DNA content were investigated in malignant cells from 41 patients exhibiting advanced gastric carcinoma. The chemosensitivity was evaluated by measuring the succinate dehydrogenase (SD) activity in drug-exposed cancer cells and the DNA content was microspectrophotometrically determined. Following exposure of malignant tissue to carboquone (CQ) and cisplatin (DDP), the mean SD activity in cells displaying a relatively regular DNA distribution (type II) was significantly higher than that in those exhibiting a widely scattered DNA distribution (type IV; P less than 0.01 in CQ, P less than 0.05 in DDP). A similar tendency was recognized in cells that were treated with aclacinomycin A (ACR), Adriamycin (ADM), and mitomycin C (MMC). Such a decrease in SD activity in cells exhibiting a type IV pattern was remarkable, especially in cases undifferentiated adenocarcinoma. Mitotic counting analysis revealed a significantly higher value for DNA pattern type IV as compared with the findings for type II (P less than 0.01). These results demonstrate that gastric carcinoma displaying a high malignant potentially shows a better response to antitumor drugs. Adjuvant chemotherapy prescribed following drug-sensitivity testing should be effective against such tumors.

Adult↗
PubMed1992

Effects of reactive oxygen intermediate scavengers on the antitoxoplasmic activity of activated macrophages.

Obioactin, Lonomycin A, muramyl dipeptide, and scavengers of hydrogen radicals and of singlet oxygen were used to study the participation of.OH and 1O2 in the killing of Toxoplasma in cultures of glycogen-induced peritoneal macrophages. Both the scavengers of OH (diazabicyclooctane and histidine) and those of 1O2 (mannitol and sodium benzoate) failed to inhibit the multiplication of Toxoplasma in macrophages that were incubated with either Obioactin, Lonomycin A, or MDP. The results of these experiments demonstrate the apparent lack of an inhibitory effect of.OH and 1O2 on the multiplication of Toxoplasma, whereas the scavengers alone inhibited the growth of the parasites.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1992

Cytotoxicity of mebendazole against established cell lines from the human, rat, and mouse liver.

The direct cytotoxicity of mebendazole (MBZ) was investigated by using cell lines derived from human, mouse and rat liver. It was demonstrated that Chang liver cells (derived from human liver) were more sensitive to the cytotoxic effects of MBZ than the other two cell lines. Longer incubation of the cells with MBZ resulted in stronger toxicity, and the cytotoxicity was dependent on the MBZ concentration above a certain threshold value (0.25-0.50 mg/l in a 42-h culture). Inhibition of the proliferation of Chang liver cells by MBZ was detected at a concentration of 0.008 mg/l, a lower concentration than that having a cytotoxic effect. The other two cell lines were less sensitive to the inhibitory effect of MBZ. Proliferation of human mononuclear cells following stimulation by phytohemagglutinin (PHA) was inhibited by MBZ, and this inhibition was more extensive than that of cells stimulated with whole formalin-treated Pseudomonas aeruginosa. It is suggested that dividing cells may be more sensitive to MBZ cytotoxicity. This anti-proliferative effect may be related to its clinically known side effects, such as hepatotoxicity and bone marrow suppression.

Animals↗
PubMed1992

Ultrasound study in the diagnosis of primary Budd-Chiari syndrome (obstruction of the inferior vena cava).

Primary Budd-Chiari syndrome, obstruction of the hepatic portion of the inferior vena cava (IVC), is a rare disorder, but relatively prevalent in the Far East, northern India and Africa. Ultrasound examination was carried out on 9 patients with primary Budd-Chiari syndrome. There were 5 men and 4 women aged 27-60 years. In all the 9 cases, the diagnosis was confirmed by cavography and liver histology. Moreover, 7 of the 9 subsequently underwent radical operation using a patch graft. Ultrasonic study showed several characteristic findings suggestive of the syndrome, and frequencies of the main findings were as follows: 1) an echogenic obstructing membrane; 22.2%, 2) segmental obstruction of the IVC; 77.8%, 3) occlusion of the major hepatic veins at the juxtacaval portion; 100%, 4) enlarged inferior right hepatic veins; 55.6%, 5) abnormal intrahepatic venous structures and collaterals; 88.9%. Of these findings, 5) was the most prominent and most characteristic in the diagnosis of the syndrome. It is necessary for early detection of this entity to evaluate carefully intrahepatic venous abnormalities and patency of either the IVC or major hepatic veins on ultrasonic examination. The careful examination for Budd-Chiari syndrome should be done in cases with cryptogenic liver cirrhosis, particularly in countries where the prevalence of the syndrome is high.

Adult↗
PubMed1992

Mechanical circulatory assist using heparin-coated tube and roller pump system.

We have invented a mechanical circulatory assist system that uses a heparin-coated tube and a roller pump. Experimental left heart bypass was performed on 13 mongrel dogs for 24 hours without systemic heparinization. There were no significant changes in coagulation variables during the experiment, and pathological examination of internal organs after bypass revealed no evidence of thromboembolism. We applied this assist system to 13 patients who could not be weaned from cardiopulmonary bypass after an open heart operation. Left heart bypass was performed on 7 patients, right heart bypass on 1 patient, combined left and right heart bypass on 2, and venoarterial bypass without oxygenation on 3. Duration of support ranged from 5 hours to 21 days, and the pump flow rate ranged from 0.8 to 3.2 L/min. Eight patients were successfully weaned from this support, and 6 were discharged from the hospital. Examination of the tubes in the assist system revealed excellent antithrombogenicity for at least 3 days without systemic heparinization. There was no evidence of thromboembolism in brain, kidneys, lungs, or other organs. Because of its simplicity and antithrombogenicity, this mechanical assist system is beneficial for patients who cannot be weaned from cardiopulmonary bypass after open heart operations.

Adult↗
PubMed1992

Intracavitary brachytherapy combined with external-beam irradiation for squamous cell carcinoma of the thoracic esophagus.

During the 15 year period from 1974 to 1988, 277 patients with previously untreated, histologically confirmed, squamous cell carcinoma of the thoracic esophagus were treated with the Time Dose and Fractionation (TDF) factor of more than 99. Of these, 161 patients were treated with external beam irradiation combined with intracavitary brachytherapy. Intracavitary brachytherapy was done for all patients for whom insertion of an outer applicator 1 cm in diameter was possible and for whom a relatively good performance status was seen at completion of external beam irradiation. Except for mild radiation-induced esophagitis, no acute radiation injuries were noted. The early clinical effect of radiation upon the esophageal lesion was determined by esophagography and esophagoscopy, approximately 1 month after the combined radiotherapy; a complete response was observed in 86 (53.4%) of the 161 patients. Furthermore, after a 5 year follow-up, local control of esophageal cancer was found to have been successful in 51 (31.7%) of the 161 patients. The highest rate of local control was associated with the following criteria: Stage I, T1, tumor length less than 5 cm, and superficial or tumorous type of tumor. The 5-year actuarial survival rates were 43.3% for Stage I, 21.1% for Stage II, and 0% for both Stages III and IV. Benign radiation-induced esophageal ulcerations or strictures did develop in five of the long-term survivors, suggesting that the dosage is close to the maximal tolerance of the esophagus. We recommend that 1500-2000 cGy in two or three fractions is the optimal dosage for intracavitary radiation of the esophageal mucosa after external irradiation of 5500 cGy in 22 fractions for 5.5 weeks or 6000 cGy in 30 fractions for 6 weeks. We believe that intracavitary treatment of esophageal carcinoma is a highly effective and a safe therapeutic modality, not only as a palliative therapy, but also as a radical treatment for patients in Stages I and II.

Aged↗
PubMed1992

A sensitive enzymatic method (SK-013) for detection of Treponema denticola, Porphyromonas gingivals and Bacteroides forsythus in subgingival plaque samples.

An enzymatic method, SK-013, was developed for rapid detection of the peptidase activity in subgingival plaque samples. This method was found to have specificity for Porphyromonas gingivalis, Treponema denticola, Bacteroides forsythus, and some Capnocytophaga strains. The purpose of this study was to determine whether SK-013 could indicate the presence of periodontopathic bacteria, including T. denticola, P. gingivalis and B. forsythus, which produce trypsin-like enzymes. Subgingival plaque samples were taken from 10 clinically healthy sites and 30 periodontally diseased sites with 3 paper points. SK-013 activity of plaque samples was assayed, and the numbers of T. denticola, P. gingivalis and B. forsythus in the sample were counted by immunofluorescence technique. In diseased sites, the SK-013 activity was significantly correlated with clinical parameters such as Gingival Index, Plaque Index, probing depth and bleeding on probing. A significant correlation was found between the presence of these organisms and SK-013 activity. Correlation coefficients between the presence of T. denticola and SK-013 activity were higher than those with other organisms. These findings indicate that the SK-013 is useful as an indicator of cell population of T. denticola, P. gingivalis and B. forsythus in subgingival plaque.

Bacteroides↗
PubMed1992

[Detection of Neisseria gonorrhoeae in first-voided urine sediments from male urethritis patients by polymerase chain reaction].

Neisseria gonorrhoeae was detected from first-voided urine sediments of male patients with urethritis by polymerase chain reaction (PCR). Urine and urinary sediment were treated with proteinase K, and DNA was further purified by phenol extraction. Two oligonucleotides based on sequences within a ribosomal RNA gene from N. gonorrhoeae were used as primers for the PCR. A DNA fragment of 206 bp specific for N. gonorrhoeae was amplified by PCR and detected by agarose gel electrophoresis. In 19 specimens of urine sediments collected from 21 patients in whom N. gonorrhoeae was isolated from urethral swab by culture, 206 bp DNA fragment was amplified by PCR. In all specimens of urine sediments from 24 patients in whom cultures for N. gonorrhoeae were negative, no DNA was amplified by the PCR. The overall coincidence rate between the PCR for detecting N. gonorrhoeae in first-voided urine sediments and culture in urethral swab was 95.6% (43/45). PCR procedure for detection of pathogens from first-voided urine sediments would be noninvasive and would be applied for the diagnosis of gonococcal urethritis and chlamydial urethritis.

Chlamydia trachomatis↗
PubMed1992

[Comparison of polymerase chain reaction and IDEIA Chlamydia in detection of Chlamydia trachomatis from first-voided urine of male urethritis patients].

We have reported a method for detection of Chlamydia trachomatis by polymerase chain reaction (PCR) with two oligonucleotides based on sequences within the major outer membrane protein gene from C. trachomatis serovar L2. In the previous report, in addition to treatment of the mixture of first-voided urine (FVU) sediment and 1 ml of urine with proteinase K. DNA purification by phenol extraction was necessary for preparation of template DNA for PCR. In this study, FVU sediment was suspended in 1 ml of Chlamydiazyme dilution buffer and a part of the suspension was treated with proteinase K for DNA extraction. The DNA extraction solution could be used as template for PCR without purification of DNA by phenol extraction. One hundred FVU specimens obtained from male urethritis patients were examined with the two methods (PCR and IDEIA) for detection of C. trachomatis. In 33 of 100 specimens, the DNA fragments of C. trachomatis was amplified by the PCR and in 32 of 100, the chlamydial antigen was detected by IDEIA. The positive and negative coincidence rate of the PCR to IDEIA were 93.8% (30.32) and 95.6% (65/68) respectively, resulting in a high overall coincidence rate at 95%. Thus, the improved method with PCR using FVU as a specimen is proved to be a useful, non-invasive diagnostic tool for diagnosis of chlamydial urethritis.

Chlamydia trachomatis↗
PubMed1992

[Culture-positive Legionella pneumonia in Japan, 1980-1990. Working Party for Legionellosis, Japanese Ministry of Health and Welfare].

The Working Party for Legionellosis headed by the Japanese Ministry of Health and Welfare processed to standardize the diagnostic procedures for Legionella pneumonia, as the first step to clarify the actual occurrence of patients with this respiratory disease. All the clinical data were collected and analysed on the 28 culture-confirmed patients in Japan during the past 11 years, from 1980 through 1990. The 28 patients were distributed throughout Japan, from Hokkaido to Kyushu. Out of 28 patients, 18 were community-acquired and 10 were nosocomially infected. In 8 of 18 community-acquired patients, any significant underlying disease was not observed. Though it was dominant in the age group in their 60s & 70s, victims were distributed in adults over 20 years of age and even in a new born baby. Only 5 out of 28 patients recovered successfully. From the autopsy findings, in 5 out of the remaining 23 expired patients, Legionella pneumonia seemed to be successfully treated, but other disease or other bacterial pneumonia put an end to the patients. The results of clinical laboratory tests and the efficacy of antibiotics to Legionella pneumonia were essentially the same as those reported in the literature.

Adult↗