Search PubMed⌕ Search

Biomedical subjects

K Shibata

Publications and source records attributed to K Shibata.

At least 955 records · Page 53Linked to original sources

Structure of the coding region and mRNA variants of the apyrase gene from pea (Pisum sativum).

Partial amino acid sequences of a 49 kDa apyrase (ATP diphosphohydrolase, EC 3.6.1.5) from the cytoskeletal fraction of etiolated pea stems were used to derive oligonucleotide DNA primers to generate a cDNA fragment of pea apyrase mRNA by RT-PCR and these primers were used to screen a pea stem cDNA library. Two almost identical cDNAs differing in just 6 nucleotides within the coding regions were found, and these cDNA sequences were used to clone genomic fragments by PCR. Two nearly identical gene fragments containing 8 exons and 7 introns were obtained. One of them (H-type) encoded the mRNA sequence described by Hsieh et al. (1996) (DDBJ/EMBL/GenBank Z32743), while the other (S-type) differed by the same 6 nucleotides as the mRNAs, suggesting that these genes may be alleles. The six nucleotide differences between these two alleles were found solely in the first exon, and these mutation sites had two types of consensus sequences. These mRNAs were found with varying lengths of 3' untranslated regions (3'-UTR). There are some similarities between the 3'-UTR of these mRNAs and those of actin and actin binding proteins in plants. The putative roles of the 3'-UTR and alternative polyadenylation sites are discussed in relation to their possible role in targeting the mRNAs to different subcellular compartments.

Actins↗

Signal pathway involved in increased expression of neutral endopeptidase 24.11 by gonadotropin releasing hormone in choriocarcinoma cells.

Neutral endopeptidase 24.11 (NEP) is known to regulate cellular functions by degrading several bioactive peptides, such as gonadotropin-releasing hormone (GnRH). The present study was performed to clarify the mechanisms of NEP expression by GnRH in human choriocarcinoma (BeWo) cells. GnRH increased NEP expression and enzyme activity in a dose- and time-dependent manner in BeWo cells. The phosphorylation levels of protein kinase C (PKC) delta, p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK1 and 2) were enhanced after 10 min exposure of 10(-6)m GnRH. The effect of GnRH on both NEP expression and enzyme activity was completely inhibited by inhibitors of PKC, PKC delta, and p38MAPK. Cell number was reduced by 54.4 per cent of the control by culture with 10(-6)m GnRH for 24 h. However, phosphoramidon, a NEP specific inhibitor, inhibited antiproliferative effect of GnRH and reverted to the control level. In conclusion, GnRH induces NEP expression by PKC delta and p38MAPK, and increased NEP expression may be involved in antiproliferative effect in BeWo cells.

Adult↗

Pattern reversal visual evoked potentials in migraine with aura and migraine aura without headache.

Pattern reversal visual evoked potentials (PVEPs) were recorded in 20 patients with migraine with aura (MA), 19 patients with migraine without headache (migraine equivalent; ME) during interictal periods, and 34 normal subjects. All migraine patients had hemianopsia or fortification spectra during attacks. In both MA and ME patients of less than 49 years of age, there were significant (p<0.01) differences in amplitude of PVEPs at the mid-occipital and contralateral to visual aura electrode sites compared to normal subjects. Amplitude of PVEPs in MA and ME showed significant (p<0.001) increases when recorded soon after attacks, especially within 10 days. There was a significant (p<0.01) correlation between percentage asymmetries and the duration of illness in both MA and ME. We conclude from our PVEP findings that cortical spreading depression remains the most likely explanation for the migraine visual aura.

Adult↗

Neoadjuvant chemotherapy for FIGO stage III or IV ovarian cancer: Survival benefit and prognostic factors.

The survival benefit of neoadjuvant chemotherapy (NAC) was assessed in patients with FIGO stage III or IV ovarian cancer, and the prognostic value of various therapeutic factors was determined. In patients treated for stage III or IV ovarian malignancies at the Department of Obstetrics and Gynecology of Nagoya University or related institutions between 1987 and 1996, 119 had a histologic diagnosis of serous cystadenocarcinoma. For this group, the long-term outcome was compared between 96 patients receiving conventional adjuvant chemotherapy following standard surgery and 23 patients treated with NAC, both followed by a second cytoreductive surgery. In a total of 29 patients with all histologic types of malignancy, the tumor response to NAC and survival were analyzed on the basis of histology, chemotherapy regimen, residual tumor size after the second cytoreductive operation, and the dose intensity of cisplatin. The long-term outcome (5-year survival rate) was better in patients treated with conventional adjuvant chemotherapy than in patients receiving NAC, although the difference was not significant. Overall survival did not differ significantly in relation to tumor histology or chemotherapy regimen. With respect to residual tumor size after the second surgery, patients with a residual tumor < or = 2 cm in diameter had a significantly better prognosis than those with a residual tumor >2 cm. A better prognosis was also associated with a higher dose intensity of cisplatin, and patients treated at >or = 18 mg/m(2)/week survived significantly longer than those receiving <18 mg/m(2)/week.

Adult↗

Asymmetrical, reciprocal translocation (45,XX,tdic(9;17) (p21;p12).

A nine-month-old girl with dysmorphic features, congenital heart disease and chromosomal mosaicism is reported. Approximately one-half of the cells (lymphocytes and fibroblasts) showed a normal karyotype 46, XX, the other half a dicentric translocation chromosome. Using the G-band technique, the dicentric chromosome was identified as a 9/17 translocation chromosome. Both centromeres of the translocation chromosome could be stained to the same degree, using the C-band technique. The centromere region of chromosome No. 9 was in addition demonstrated, by using the Giemsa 11 technique.

Abnormalities, Multiple↗

Prognostic importance of vascular endothelial growth factor and its receptors in the uterine sarcoma.

Vascular endothelial growth factor (VEGF) and its receptors play an important role in tumor progression; however, there is no report regarding this factor in uterine sarcoma. Thirty-nine patients with uterine sarcoma, 14 carcinosarcomas, 4 endometrial stromal sarcomas, and 21 leiomyosarcomas, were studied. By immunohistochemical staining, VEGF was not detected in normal uterine smooth muscle, but VEGF receptor-1 (flt-1) and VEGF receptor-2 (flk-1) were observed in 14 and 4 of 14 normal smooth muscles, respectively. Of 39 sarcomas, 25 expressed VEGF, and 38 and 34 sarcomas expressed flt-1 and flk-1 at various intensities, respectively. The staining intensity of VEGF, flt-1, and flk-1 was significantly higher in sarcoma than in normal uterine smooth muscle, but that of phospho-flt-1 (p-flt-1) was significantly lower in sarcoma than in normal uterine smooth muscle. When sarcomas were divided into two groups according to staining intensity, a significant difference in survival curves was observed in only p-flt-1 of leiomyosarcoma (P= 0.008), and in all sarcomas, a lower survival curve was also observed in the high staining intensity group than in the low staining intensity group, although there was no significant difference (P= 0.102). In conclusion, VEGF and its receptors are suggested to be involved in progression of uterine sarcoma, but only the p-flt-1 level significantly affected the survival of leiomyosarcoma patients.

Adult↗

A 'neural' response with 3-ms latency evoked by loud sound in profoundly deaf patients.

A large negative deflection with a latency of 3 ms was observed in the auditory brainstem response (ABR) waveforms of some patients with peripheral profound deafness. This deflection was termed the N3 potential. In this paper, we review patients with the N3 potential and discuss the characteristics of abnormal ABR waveforms. The origin of the N3 potential was also discussed, especially with respect to vestibular evoked potentials. In most of the patients, audiograms showed no response to the maximum output of an audiometer in the high-frequency range and a residual response in the low-frequency range. The N3 potentials were noted at intensities of 80 dB nHL or greater. As the stimulus intensity increased, the amplitude of the potential increased and the latency decreased. A high repetition rate (83.3/s) of the click stimulus influenced the latency and amplitude of the N3 potential. The potential was replicated on retest within less than a month, and had a consistent latency and amplitude over the scalp. The results indicate that the N3 potential is not an electrical artifact but a physiological neural response evoked by a loud sound. The N3 potential is most likely not an auditory evoked response from cochlear or a response from a semicircular canal, because it has a 3-ms latency, a sharp waveform, and is unassociated with vertigo. The results suggest that the N3 potential may be a saccular acoustic response.

Acoustic Stimulation↗

Circulating endothelial cells fail to induce cerebral infarction in rabbits.

Exfoliated cells that appear to be circulating endothelial cells were detected in human blood. Because the size of endothelial cells is larger than that of other circulating blood cells, we investigated whether the increased number of circulating endothelial cells might be responsible for cerebral embolism. We compared rabbits into which suspensions of endothelial cells were injected through the common carotid arteries with control rabbits into which blood clots or arachidonic acid were administered in the same manner. Injected endothelial cells failed to cause cerebral embolism. Because the majority of exfoliated circulating endothelial cells were degenerated and deformed, the suspensions of endothelial cells obtained from rabbit aortas were treated by ultrasonic waves. These suspensions also failed to cause cerebral embolism. We conclude that cerebral embolism cannot be induced by an increase of circulating endothelial cells alone.

Animals↗

A case of malignant lymphoma accompanied with arterial bleeding from the gastric lesion.

We experienced a case of malignant lymphoma with gastric and ileo-caecal lesions. The case was 80 year-old Japanese female with a chief complaint of anorexia. The patient had gross hematemesis on the 4th day of admission. By emergency gastroendoscopy, multiple small gastric ulcers which have sharp marginal prominences were observed. Pulsating arterial bleeding was observed and we successfully achieved hemostasis by topical injection of pure ethanol under gastroendoscopy. Biopsy specimen of that lesion showed it was malignant lymphoma.

Aged↗

Subtotal peritonectomy with chemohyperthermic peritoneal perfusion for peritonitis carcinomatosa in gastrointestinal cancer.

Treatment for peritonitis carcinomatosa in gastrointestinal cancer remains to be established though it is one of the commonest causes of cancer death. Subtotal peritonectomy (SP) with chemohyperthermic peritoneal perfusion (CHPP) was developed for the new therapeutic strategy for peritoneal dissemination in gastrointestinal cancer in our department. SP includes resection of stomach, colon, small bowel, spleen, gall bladder, and parietal peritoneum. CHPP was carried out by heated saline containing 25 mg/l cisplatin, 10 mg/l mitomycin C, and 20 mg/l etoposide. Intraperitoneal temperature was maintained at 42 degrees C for 60 min. Fifteen gastric cancer and three colon cancer patients with severe peritoneal dissemination underwent these procedures. The averages of operating time, intraoperative bleeding volume, and total perioperative transfused blood volume were 9 h, 4400 ml, and 5600 ml, respectively. The patients estimated as complete resection and residual disease by histopathological study numbered 11 and 7. There was no treatment-related deaths though bleeding occurred in 5 patients; perforation in 2 patients; and abscesses in 2 patients. The 1-year survival rate (1ysr) and the 2-year survival rate (2-ysr) of all the patients were 57% and 21%, respectively. The 1-ysr and the 2-ysr of the patients who underwent complete resection were 67% and 40% significantly greater than the 43% and 0% of the patients who had residual tumors (p=0.02). The combination therapy of SP and CHPP is feasible in spite of its morbidity and has great possibilities in complete resection of peritoneal dissemination and prolongation of patient's survival.

Adult↗

Patterns of lymph node metastasis in carcinoma of the distal bile duct.

BACKGROUND/AIMS: The aim of this study was to clarify the lymphatic spread in distal bile duct carcinoma in relation to local tumor extent (pT category). METHODOLOGY: The distribution and number of involved nodes were examined in 42 patients with distal bile duct cancer. RESULTS: Lymph node metastases were present in 25 of 42 patients (60%); 5 of 12 (42%) with pT2 tumors and 20 of 26 (77%) with pT3 tumors. Nodal involvement was not identified in 4 patients with pT1 tumors. The incidence of node positivity was higher in patients with pT3 tumors than in those with pT1 or pT2 tumors (p<0.01 or p<0.05). The total number of positive nodes was greater in patients with pT3 tumors than in those with pT2 tumors (mean: 3.08 vs. 0.75; p<0.01). All node-positive patients had involved nodes in the hepatoduodenal ligament or posterior pancreaticoduodenal region, or both. The number of positive nodes in the superior mesenteric and para-aortic region was greater in patients with pT3 tumors than in those with pT2 tumors (p<0.05). CONCLUSIONS: As tumor invades the pancreas from the distal bile duct, lymphatic spread extends from the hepatoduodenal ligament or posterior pancreaticoduodenal region to the superior mesenteric and para-aortic nodes.

Adult↗

Suppression of N(epsilon)-(carboxymethyl)lysine generation by the antioxidant N-acetylcysteine.

OBJECTIVE: Accumulated evidence suggests that N(epsilon)-(carboxymethyl)lysine (CML), which is a dominant antigen of advanced glycation end-products (AGEs), is generated in the peritoneal cavity of patients undergoing continuous ambulatory peritoneal dialysis (CAPD), and that this process may be involved in the pathophysiology of the peritoneal injury found with CAPD treatment. Since CML is a sequential product of glycation and oxidation processes, CML generation could be suppressed by antioxidants. The aim of this in vitro study was to clarify the effect of N-acetylcysteine (NAC), an antioxidant, on CML generation from proteins under high glucose settings mimicking peritoneal dialysis solutions. DESIGN: Test proteins (bovine serum albumin/type I collagen) were incubated continuously for 16 weeks in glucose solutions (200 mmol/L) with or without NAC (2 mmol/L), and the generation time courses (8 and 16 weeks) of CML and furosine (the biomarker of the glycation products of the early Maillard reaction) were determined. RESULTS: In both proteins, furosine and CML were progressively generated in accordance with the duration of the incubation period. No apparent differences were found between solutions with and without NAC in furosine levels at the 8th and 16th weeks. However, the generation of CML was lower in the solution with NAC throughout the test periods. CONCLUSION: The results showed that NAC could suppress the generation of CML. This indicates the therapeutic potential of antioxidants for the glycoxidative stress-related peritoneal injury occurring during CAPD.

Acetylcysteine↗

Patterns of lymph node metastasis in carcinoma of the ampulla of Vater.

BACKGROUND/AIMS: Identification of lymph node metastasis may guide surgical therapy. The aim of this study was to clarify the lymphatic spread in ampullary carcinoma in relation to local tumor extent (pT category in the pTNM classification). METHODOLOGY: The distribution and number of lymph node metastases were histologically examined in 35 patients with ampullary carcinoma. RESULTS: Lymph node metastases were present in 10 of 15 patients (67%) with pT2 tumor and in 10 of 11 (91%) with pT3 tumor. Nodal involvement was not identified in 9 patients with pT1 tumor. The incidence of node-positive patients was higher in pT2 and pT3 tumors than in pT1 tumors (P < 0.01). The total number of positive nodes per node-positive patient was greater in pT3 tumors than in pT2 tumors (mean 3.50 vs. 1.30, P < 0.001). All node-positive patients had metastasis to the posterior pancreaticoduodenal node. The number of positive nodes per node-positive patient in both the posterior pancreaticoduodenal and the superior mesenteric region was greater in pT3 tumors than in pT2 tumors (P < 0.01 and P < 0.05). CONCLUSIONS: With increasing pT category in ampullary carcinoma, lymphatic spread extended from the posterior pancreaticoduodenal region to the superior mesenteric nodes.

Aged↗

Evaluation of several saccharides as osmotic agent for peritoneal dialysate.

OBJECTIVE: The carbonyl group of glucose reacts non-enzymatically with the amino group of protein to form advanced glycosylation end-products (AGEs). AGEs are found in the peritoneum of continuous ambulatory peritoneal dialysis patients, and this AGE formation is suspected to be one of the causes of impaired peritoneal function. In order to control AGE formation in the peritoneum, AGE formation and ultrafiltration in rats were examined with peritoneal dialysates using as osmotic agents saccharides that lack a carbonyl group, the saccharic acid lactobionate [molecular weight (MW) 358.30], the sugar alcohol maltitol (MW 344.32), and the nonreducing sugar nistose (MW 666.58). DESIGN: Bovine serum albumin (BSA) (25 mg/mL) was incubated with 18, 36, and 72 mg/mL maltitol, lactobionate, nistose, and glucose at 37 degrees C. After 3 or 6 weeks, amounts of furosine and N-(carboxymethyl) lysine were measured. A 20-mL intraperitoneal injection of a lactate-based dialysate (osmotic pressure 388 mOsm/kg) containing 4.34% maltitol, 4.52% lactobionate, or 8.4% nistose was given to Sprague-Dawley rats and, after 2, 4, or 6 hours, the quantity of effluent and levels of urea nitrogen and creatinine in the effluent and in serum were measured. RESULTS: No increases in furosine or N-(carboxymethyl) lysine were seen with maltitol, lactobionate, or nistose after 3 and 6 weeks of incubation with BSA; AGE formation was not observed. In the study in rats, the quantity of abdominal fluid after a 6-hour dwell was nistose > lactobionate > maltitol > glucose. No differences in dialysate-to-plasma ratios for urea nitrogen or creatinine were seen in any group. CONCLUSIONS: AGE formation in peritoneal tissue might be controlled by using saccharides with a modified carbonyl group as osmotic agents for peritoneal dialysates. Nistose is considered to yield the most efficient dialysis.

Animals↗

Effects of herbimycin A derivatives on growth and differentiation of K562 human leukemic cells.

Herbimycin A, a specific tyrosine kinase inhibitor, induced erythroid differentiation of human myelogenous leukemia K562 cells with a high level of bcr/abl tyrosine kinase. Several derivatives of herbimycin A were synthesized and their effects on cell proliferation and differentiation of K562 cells were examined. Of the compounds tested, 19-allylaminoherbimycin A was the most effective in inducing differentiation of K562 cells. However, the parent compound was the most potent growth inhibitor, suggesting that chemical modification of herbimycin A reduces the growth-inhibiting activity. The sensitivities of K562 cells to herbimycin derivatives were different from those of a rat kidney cell line infected with Rous sarcoma virus (v-src), suggesting that bcr/abl kinase may differ in sensitivity from other tyrosine kinases. These results indicate that a specific inhibitor of bcr/abl kinase could be an effective antitumor agent against chronic myelogenous leukemia.

Adult↗