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K Kitamura

Publications and source records attributed to K Kitamura.

At least 703 records · Page 39Linked to original sources
PubMed1992

Crystallization and preliminary X-ray study of the cathepsin B complexed with CA074, a selective inhibitor.

Cathepsin B from bovine spleen has been purified and crystallized as a complex with a specific inhibitor CA074 [N-(L-3-trans-propylcarbamoyloxirane-2-carbonyl)-L- isoleucyl-L-proline], using the hanging-drop method. The complex crystals obtained from 50 mM-citrate buffer (pH 3.5) belong to the tetragonal space group P4(1) (or P4(3)) with a = 73.06 A and c = 141.59 A, and diffract beyond 2.2 A resolution. There are two complex molecules per asymmetric unit giving a packing density of 3.37 A3/Da and indicating a high solvent content of 63.5%.

Animals↗
PubMed1992

Organ distribution and characterization of porcine peptides (VIP, CGRP and PHI) that increase cAMP in rat platelets.

Using an assay for rat platelet cAMP, we investigated the organ distribution of peptides that increase cAMP in rat platelets in porcine tissues. Marked activity was observed in the duodenum, pancreas and brain. By analysis with reverse phase high performance liquid chromatography (HPLC), three major peaks of activity were observed in porcine tissues. The first peak was vasoactive intestinal polypeptide (VIP), and the second peak was calcitonin gene-related peptide (CGRP). The third peak of activity was isolated from porcine duodenum. By analysis with a gas phase sequencer and with an amino acid analyzer, this peptide was identified as peptide histidine isoleucine (PHI). In a glucagon-secretin family of neuropeptides, pituitary adenylate cyclase activating polypeptide (PACAP) significantly increased platelet cAMP levels in a dose-dependent manner; however, glucagon did not. These results suggest that not only VIP and CGRP but also PHI and PACAP act upon platelets, as well as vascular tissues.

Amino Acid Sequence↗
PubMed1992

Cell cycle dependent gene expressions and activities of protein phosphatases PP1 and PP2A in mouse NIH3T3 fibroblasts.

We determined the mRNA levels and the activities in nuclear and non-nuclear fractions of protein phosphatase type 1 (PP1) and type 2A (PP2A) through the cell cycle in synchronized mouse NIH3T3 fibroblasts. The mRNA level for PP1 alpha was gradually elevated in late G1 phase, began to decrease in M phase, and reached the control level with entering into the next G1 phase. The mRNA level for PP2A was rapidly increased in early G1 phase, kept at the high level, and decreased after S phase. In nuclear fractions of cells, spontaneous activities of both PP1 and PP2A were gradually increased until M phase and rapidly decreased with entering the next G1 phase, while in non-nuclear fraction such dramatic alterations were not observed. Potential activities of PP1 in both fractions revealed by Co(2+)-trypsin treatment showed an oscillaion patterns similar to those of the spontaneous activities. These results strongly suggest that cell cycle dependent gene expressions and activities of PP1 and PP2A play roles in DNA synthesis and mitosis during the cell cycle.

Animals↗
PubMed1992

Glycopeptide of P0 protein inhibits homophilic cell adhesion. Competition assay with transformants and peptides.

Expression of major myelin glycoprotein P0 by P0 cDNA transfection into C6 glioma cells promoted homophilic cell adhesion of the cells. After the dissociated cells were incubated for various times, the number of particles at each time point was measured. The total number of particles decreased to 24% in 60 min for transformant (C6P0) cells, in contrast to only 68% for control (C6P0') cells. To confirm the homophilic mechanism of adhesion, mixed-cell aggregation experiments were performed. Among the four synthetic peptides corresponding to a part of the P0 sequence used, only peptide 3 (residues 90-96), which contained a carbohydrate attaching site, caused considerable inhibition of cell aggregation (approximately 50%). In addition, the glycopeptide (residues 91-95) obtained from bovine P0 markedly inhibited cell aggregation (by approximately 85%).

Amino Acid Sequence↗
PubMed1992

Purification and characterization of S-modulin, a calcium-dependent regulator on cGMP phosphodiesterase in frog rod photoreceptors.

S-modulin is a 26 kDa protein that regulates light sensitivity of cGMP phosphodiesterase in a Ca(2+)-dependent manner in frog rod outer segments (ROSs). In the present study, we purified S-modulin by taking advantage of a hydrophobic interaction between Phenyl Sepharose and S-modulin at high Ca2+ concentrations. The yield was greater than 90%. 45Ca(2+)-binding experiment showed that S-modulin is a Ca(2+)-binding protein. At high Ca2+ concentrations, S-modulin binds to ROS membranes. The binding target of the Ca2+/S-modulin complex is possibly a ROS membrane lipid(s), but it was difficult to identify. The binding was observed mainly at greater than 1 microM Ca2+. The amino acid sequence deduced from proteolytic fragments of S-modulin was approximately 80% and 60% identical to those of recovering and visinin, respectively.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1992

Isolation and characterization of peptides which act on rat platelets, from a pheochromocytoma.

An increase in the cellular concentration of cAMP leads to the inhibition of platelet aggregation. We have been investigating endogenous peptides which inhibit platelet function, using an assay which detects increase in platelet cAMP. Compared with the human adrenal medulla, a pheochromocytoma (PC) contained abundant peptides that elevate platelet cAMP. About 90% of the activity was found in the SP-III fraction which contained strongly basic peptides. From the SP-III fraction, peptides P-1, P-2 and P-3 were purified to homogeneity as endogenous peptides which elevated platelet cAMP. A gas phase sequencer was used to identify these peptides as follows: P-1 = vasoactive intestinal peptide (VIP); P-2 = calcitonin gene related peptide-I (CGRP-I); P-3 = CGRP-II. It is well known these peptides are potent vasorelaxants. VIP and CGRP-I significantly increased platelet cAMP levels 15- and 6-fold, respectively. These results suggest that VIP and CGRP-I and -II act upon platelets as well as upon vascular tissue.

Adrenal Gland Neoplasms↗
PubMed1992

Gene expressions and activities of protein phosphatases PP1 and PP2A in rat liver regeneration after partial hepatectomy.

We have examined the levels of gene expressions and activities of protein phosphatases, PP1 and PP2A, in rat regenerating livers. PP1 alpha mRNA started to increase from 6 h after partial hepatectomy (PH) and showed two peaks at 12 and 48 h. PP2A mRNA level showed two peaks at 6 and 10-12 h. Protein phosphatase activities were determined both in non-nuclear fraction and in nuclei. While spontaneous PP1 activity in non-nuclear fraction was nearly constant, potential PP1 activity revealed by Co(2+)-trypsin treatment showed a small peak between 7 and 12 h. In nuclei, both spontaneous and potential PP1 activity began to increase from 4-7 h after PH, reached a maximum (about 2.5-fold over control levels) at 12 h, the time which corresponds to the G1 to S transition in the cell cycle, and then declined back to control levels by 7 days. PP2A activity in non-nuclear fraction was nearly constant in both spontaneous and potential forms. PP2A activity in both forms in nuclei was very low throughout. These results suggest the possibility that PP1 in nuclei plays some role in the G1 to S transition in the cell cycle of hepatocyte proliferation.

Animals↗
PubMed1992

Prophylaxis with carbon-adsorbed mitomycin against peritoneal recurrence of gastric cancer.

Attempts to prevent peritoneal carcinomatosis after surgery for gastric cancer by intraperitoneal administration of anticancer drugs have not been successful, largely because the drugs are not retained in the peritoneal cavity. We have assessed the prophylactic efficacy of a delayed-release preparation--mitomycin adsorbed onto activated charcoal (M-CH). 50 patients with gastric cancer and serosal infiltration were randomly assigned intraperitoneal treatment with M-CH (50 mg mitomycin intraoperatively) or no anticancer prophylaxis (control). Survival rates for the 3 years of follow-up were significantly higher among the 24 M-CH recipients (1 was lost to follow-up) than among the 25 controls (p less than 0.01). There were significant differences in survival between the groups at 1.5 years after randomisation (difference 34.6% [95% confidence interval 8.5-60.8%]; p less than 0.01) and at 2.0, 2.5, and 3.0 years (41.7% [14.2-69.1%]; p less than 0.005). The concentration of mitomycin was significantly higher in peritoneal exudate than in plasma for 24 h after drug administration. Side-effects were slight and well tolerated. Thus, peroperative intraperitoneal treatment with M-CH seems to improve survival after gastrectomy for gastric cancer, presumably by a prophylactic effect on peritoneal recurrence.

Adsorption↗
PubMed1992

Concurrent adrenal pheochromocytoma and papillary adenocarcinoma of the thyroid in a 20-year-old man.

A 20-year-old man was admitted to Kyushu University Hospital with complaints of severe headache and episodic hypertension (200/100 mmHg). Ultrasonograms and computed tomographs revealed tumors in the left adrenal region and in the right lower lobe of the thyroid gland. Total thyroidectomy and left adrenalectomy were performed. The excised thyroid tumor and adrenal tumor were pathologically diagnosed as papillary adenocarcinoma and pheochromocytoma, respectively. A chromosome analysis revealed no karyotypic abnormality. Whereas the world literature records such occurrences in women, this is the first report of a simultaneous occurrence of pheochromocytoma and papillary adenocarcinoma of the thyroid in a young man.

Adenocarcinoma, Papillary↗
PubMed1992

Isolation and characterization of recoverin-like Ca(2+)-binding protein from rat brain.

Rat brain was found, by immunoblot analysis, to have a protein of Mr 23,000 (P23k) that was clearly different from recoverin and was labeled with an antiserum raised against the NH2-terminus of recoverin. P23k could not be detected by an antiserum raised against the COOH-terminus of recoverin. Blots with 45Ca demonstrated that P23k bound Ca2+. This calciprotein was further purified by Ca(2+)-dependent hydrophobic interaction and ion-exchange chromatography. In SDS polyacrylamide gel electrophoresis, P23k had an apparent Mr of 21,000 in the presence of 10 microM Ca2+ and 23,000 in the absence of Ca2+ (0.1 mM EGTA). The isoelectric point of P23k was 5.6. Ca(2+)-binding analysis indicated that P23k bound 2 moles of Ca2+ per mole of protein and had two binding sites with dissociation constants of 13 microM and 0.2 microM. Purified P23k bound to the crude membrane fractions from the cerebellum, cerebrum and retina in a Ca(2+)-dependent manner. Partial amino acid sequence analysis of proteolytic fragments of P23k revealed the sequence homology between P23k and recoverin. These results suggested that P23k may act as a Ca(2+)-sensitive regulator by forming a complex with its target on the membrane.

Amino Acid Sequence↗
PubMed1992

Gastric involvement of oesophageal squamous cell carcinoma.

Among 402 patients with squamous cell carcinoma of the oesophagus, gastric wall involvement was evident in 32 (8.0 per cent). These could be grouped into four types according to the pattern of involvement: group 1 included six patients with gastric involvement via metastases in perigastric lymph nodes; group 2 consisted of 11 patients with gastric intramural metastasis; group 3 contained 12 with direct invasion of the gastric wall by the oesophageal squamous cell carcinoma; and group 4 three patients with intraepithelial spread of oesophageal cancer to the gastric epithelium. Prognosis was poor, all patients dying except for one in each of groups 3 and 4. The mean survival time was 5.6, 8.6, 14.8 and 18.7 months in groups 1, 2, 3 and 4, respectively. Gastric involvement via metastases to lymph nodes and by intramural metastasis therefore indicates an extremely poor prognosis, while the prognosis in groups 3 and 4 was influenced by the depth of invasion and lymph node metastasis of the oesophageal cancer. Histological examination of tissues from group 4 patients demonstrated that malignant squamous cells proliferated and invaded the gastric epithelial layer, that is, there was intraepithelial spread of the oesophageal cancer.

Aged↗
PubMed1992

Chemically humanized murine monoclonal antibody against a cell nuclear antigen: usefulness in autoimmune diagnostics.

The cellular nuclear antigen SS-B/La is known to be a major antigenic target to an autoantibody in patients with Sjogren's syndrome and systemic lupus erythematosus. It is useful to detect an anti-SS-B/La antibody from patients' sera in a clinical point of view. We purified SS-B/La from rabbit thymus acetone powder by affinity chromatography with a murine anti-SS-B/La monoclonal antibody (1C3-H7). An enzyme-linked immunosorbent assay method, in which SS-B/La was used to coat a plate, was also successfully established. It is difficult to obtain a large volume of patient's serum with high antibody titer and high specificity as a positive control. We investigated whether or not a positive control from human could be replaced by a murine monoclonal antibody to SS-B/La. The 1C3-H7 was conjugated with a human IgG Fc' fragment using N-gamma-maleimidobutyryloxysuccinimide as a cross-linker. The chemically humanized murine monoclonal antibody (1C3-Fc') was recognized by antiserum specific for human IgG Fc fragment. 1C3-Fc' reacted to SS-B/La but not to other antigens. Furthermore, the titration curve of this conjugate ran parallel with those of patients' sera specific for SS-B/La. It is concluded that a chemically humanized murine monoclonal antibody is useful as a positive control in place of a human patient's serum.

Animals↗
PubMed1992

Determination of the resection line in early esophageal cancer using intraoperative endoscopic examination with Lugol staining.

Determination of the resection line using intraoperative endoscopic examination with Lugol staining was performed when preoperative examinations such as an esophagogram could not be effectively carried out and the carcinoma was not palpable from the outer surface of the esophageal wall. During the past two years, we performed this technique on eight patients. The carcinoma was restricted within the epithelium in one, the mucosal layer in five, and the submucosal layer in two. Although intraepithelial carcinoma contiguous to the main lesion was seen in six and cancer multiplicity was evident in two, all of the resected stumps were free of any cancer tissue. There have been no cases of recurrence and a limited operation, such as distal esophagectomy, was able to be performed in six. Therefore, intraoperative endoscopic examination is useful for early esophageal cancer.

Aged↗
PubMed1992

Synergistic effects of intratumor administration of cis-diamminedichloroplatinum(II) combined with local hyperthermia in melanoma bearing mice.

The synergistic effect of local hyperthermia (LHT) with intratumor injection (i.t.) of cis-diamminedichloroplatinum (II) (DDP) was studied using a rodent model with implanted B16 melanoma tumors. The hindfoot of the C57BL/6 mouse bearing the tumor was placed in a water bath at 42.5 +/- 0.2 degrees C (intratumor temperature was at 42.3 +/- 0.1 degrees C) for 30 minutes just after local (i.t.) or systemic (intraperitoneal;i.p.) administration of DDP (1-3 mg/kg once in experiment I and 1-3 mg/kg three times in experiment II). The tumor growth ratio (TGR) at 7 days after treatment in the group given DDP 3 mg/kg (i.t.) with LHT was 1.1 in experiment I and 0.5 in experiment II, and there was a statistically significant difference in both experiments compared to findings in other groups (P < 0.01). The mean survival time was 42.1 days in experiment I and 50.2 days in experiment II, with a significant difference in the latter (P < 0.001). Thus regional injection chemotherapy given concomitantly with local hyperthermia promotes the anticancer effects and improves the prognosis without either severe renal injury or the promotion of hematogenic metastasis.

Animals↗
PubMed1992

A case of localized peritonitis caused by obstructive colitis proximal to rectal carcinoma: a rare manifestation of obstructive colitis.

A case of obstructive colitis associated with rectal carcinoma in a 56 year old Japanese man is reported herein. He presented to Shinkokura Hospital with severe abdominal pain following a one month history of anal bleeding and mild abdominal pain. On palpation, muscle guarding was observed in the left lower quadrant and the white blood cell count was 14,200/mm3. An exploratory laparotomy was performed under the provisional diagnosis of acute abdomen, which revealed localized peritonitis 8 cm oral to an area of rectal carcinoma. An anterior resection of the lesion was therefore performed together with a descendo-proctostomy. The histopathologic diagnosis revealed adenocarcinoma and obstructive colitis involving the entire thickness of the sigmoid colon and resultant fibrino-purulent peritonitis. His post-operative course was uneventful and he was continuing to do well on the 30th postoperative day, at the time of writing. The clinical significance of this combination of obstructive colitis with rectal carcinoma is briefly discussed following the presentation of this case.

Adenocarcinoma↗