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Biomedical subjects

E Kobayashi

Publications and source records attributed to E Kobayashi.

At least 307 records · Page 17Linked to original sources
PubMed1994

High rates of Ki-ras point mutation in both intra- and extra-hepatic cholangiocarcinomas.

The presence of the Ki-ras gene mutations in 14 cases of intrahepatic cholangiocarcinoma (IHC) and nine cases of extrahepatic cholangiocarcinoma (EHC) were investigated by polymerase chain reaction-single strand conformation polymorphism analysis. To obtain enriched tumor cell DNA, the microdissection method was used on formalin-fixed paraffin-embedded tissue sections. Point mutations at codon 12 of the Ki-ras gene were detected in seven (50%) of the 14 cases of IHC and six (67%) of the nine EHC cases. In all but one of the ras gene mutation cases, G to A transitions in the second position of codon 12 were detected, the exception being a G to T transition in the same position in one IHC. No point mutations were detected at codon 13 or 61 in either IHC or EHC. Furthermore, there was no demonstrable correlation between Ki-ras mutation and patient age, tumor Stage, histological findings or prognosis. The present results demonstrated a higher participation of Ki-ras gene mutations in EHC than found in previous studies, and provided a confirmation and extension of the results earlier reported by Tada et al. and Tsuda et al. for IHC.

Adult↗
PubMed1994

[A case report of giant epidermoid in the temporal lobe: considerations of the occurrence of intramedullary epidermoids].

A case of giant epidermoid which was mainly located in the right temporal lobe was presented. The intracranial epidermoid is commonly located in the CSF space, such as the cerebello-pontine (C-P) angle, parasellar region, middle cranial fossa and ventricles. The intramedullary epidermoid is extremely rare. We report the case of a 51-year-old female suffering from generalized convulsions. Having fallen into a semicoma due to the convulsions, she was referred to our department on August 5, 1992. Neurological examination revealed slight dementia but no other deficits. The tumor was mainly located in the temporal lobe but communicated with the CSF space of C-P angle through a narrow channel shown on MRI. She underwent an operation for tumor removal and left the hospital with no neurological deficits. Several cases of intracranial intramedullary epidermoid have been reported in the literature, but none of them proved to be completely intramedullary. On operation or on CT and MRI, all of them were shown to communicate with the CSF space. The possible occurrence of an epidermoid from medullary substance was discussed.

Brain Diseases↗
PubMed1994

[A case of dural arteriovenous malformation on the convexity adjacent to the superior sagittal sinus].

A case of dural arteriovenous malformation (DAVM) on the convexity adjacent to the superior sagittal sinus (SSS) was reported. A 55-year-old female was admitted to our hospital complaining of severe headache and intracranial bruit. CT scan revealed an osteolytic lesion at the right frontal bone adjacent to the SSS, and MRI showed a flow void area at the same site. Cerebral angiography detected DAVM which was fed by bilateral superficial temporal arteries and plenty of meningeal branches of the middle meningeal artery. It was drained by cortical veins to the SSS. Endovascular surgery was tried for this lesion, but it failed. After the surgical excision of DAVM, the above symptoms disappeared with no complications. The 14 cases reported in the literature were examined to characterize DAVM at this site. Average age was 47 with no age distribution. 43% of the cases had intracranial hemorrhage, subarachnoid hemorrhage (2), intracranial hemorrhage (2), intraventricular hemorrhage (1), and subdural hematoma (1). The DAVM arises most frequently at the middle third of the SSS and tends to extend to the posterior third. The symptom most frequently seen is headache, but we ought to pay attention to the possibility of progressive dementia. As for therapy, direct surgical excision is sometimes necessary if intravascular embolization ends in failure or incomplete cure.

Cranial Sinuses↗
PubMed1994

[Surgical indication for unruptured cerebral aneurysm in patients with ischemic cerebrovascular disease].

A series of 44 cases is presented of patients who received surgical treatment for unruptured aneurysms in the anterior circulation, and which were associated with ischemic cerebrovascular disease (CVD). The age of patients varied from 34 to 76 (mean 62.8) years old. The associated ischemic CVD was transient ischemic attack (TIA) in ten, minor completed stroke in 23, and major completed stroke in 11 cases. Thirty five patients recovered fully. However, there were three deaths due to new cerebral infarction or delayed intracranial hemorrhage within 30 days after surgery (mortality 6.8%). Transient morbidity occurred in four patients (9.1%), and permanent morbidity in two patients (4.5%). In six cases, new ischemic events occurred after the surgery. In contrast, all 40 patients whose unruptured aneurysms were not associated with CVD fully recovered from the surgery they underwent. The authors indicate three risk factors which might lead to complication; diabetes mellitus, aneurysms located in the middle cerebral artery, and those larger than 6mm in diameter. Another three life-threatening factors are; elderly patients (> 65 year-old), male, aneurysms larger than 7mm in diameter. Direct surgery for unruptured aneurysms in ischemic CVD patients should be considered in cases free of risk factors indicated above. Eight cases in this series had extracranial carotid artery stenosis on the same side as the aneurysm. Carotid endoarterectomy (CEA) was performed prior to aneurysmal clipping in six patients, and their postoperative courses were excellent. In two patients, clipping was performed prior to CEA, and transient morbidity occurred in one of them.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Increased expression of nucleoside diphosphate kinase/nm23 and c-Ha-ras mRNA is associated with spontaneous lung metastasis in rat-transplantable osteosarcomas.

The relationship between expression of nucleoside diphosphate kinase (NDP kinase)/nm23, c-Ha-ras, and c-myc genes and metastatic potential was assessed in rat-transplantable osteosarcoma lines, derived from spontaneous and chemical carcinogen (4-hydroxyamino quinoline 1-oxide)-induced osteosarcomas in Fischer 344/NS1c rats. These osteosarcomas possess metastatic potential and highly metastatic lines spontaneous osteosarcoma-selected lung metastatic lesions and 4-hydroxyamino-quinoline 1-oxide-induced osteosarcoma-selected lung metastatic lesions were respectively established by selectively transplanting lung metastatic lesions. Northern blot analysis revealed that the levels of NDP kinase/nm23 and c-Ha-ras gene expression were increased in line with metastatic ability; thus transcript levels were remarkably greater in both spontaneous osteosarcoma-selected lung metastatic lesions and 4-hydroxyamino-quinoline 1-oxide-induced osteosarcoma-selected lung metastatic lesions highly metastatic lines than in their respective low metastatic spontaneous and chemical carcinogen (4-hydroxyamino quinoline 1-oxide)-induced osteosarcoma counterparts. c-myc mRNA expression was observed in all tumor lines, without any correlation with metastatic ability. Southern blot analysis did not show evidence of gross rearrangement or amplification of NDP kinase/nm23, c-Ha-ras, or c-myc genes suggesting regulation of their gene expression at the transcriptional and/or posttranscriptional level. These results indicate that NDP kinase/nm23 and c-Ha-ras might be cooperatively involved in a positive manner in signal transduction processes, especially involving G-protein reactions, responsible for metastasis of rat-transplantable osteosarcomas.

Animals↗
PubMed1993

Alteration of the structural properties of starch components by the lack of an isoform of starch branching enzyme in rice seeds.

This study describes the effect of starch-synthesizing enzymes on biosynthesis of storage starch in rice amylose-extender mutants, which contain branched D-glucans with abnormal structures. Western blot analysis indicated that two out of five amylose-extender mutant lines lacked an isoform of starch branching enzyme, termed RBE3, although the levels of granule-bound starch synthase and a major form of branching enzyme, RBE1, were normal in these two mutants. Proteins corresponding to the 87-kDa RBE3 molecule were present in the three other amylose-extender mutants as well as in the wild type. However, the level of branching enzyme activity significantly decreased in all amylose-extender mutants, suggesting that the 87-kDa proteins in these three mutants are inactive forms of RBE3. Therefore, we conclude that formation of the abnormal branched glucans in the amylose-extender mutant of rice is due to the lack of the RBE3 activity. The cDNA clones encoding RBE3 have been identified from a normal rice seed cDNA library in lambda gt11, using a synthetic oligonucleotide as a probe. The deduced amino acid sequence of RBE3 indicates that this protein is initially synthesized as a precursor of 825 amino acids, including a 65-residue transit peptide at the NH2 terminus. The sequences of the catalytic regions in amylolytic enzymes are highly conserved in the sequence of RBE3. Thus, the branching enzyme isoform belongs to a family of the amylolytic enzymes. RBE3 also shares a noticeable degree of sequence identity with RBE1, especially at the central portion of the protein molecule. However, RBE3 possesses an approximately 70-residue extra sequence at the NH2 terminus and lacks a COOH-terminal sequence of almost 50 residues as compared with RBE1. The structural differences at both termini may explain the distinct role in starch synthesis for RBE1 and RBE3.

1,4-alpha-Glucan Branching Enzyme↗
PubMed1993

Retransplantation of the liver in the rat.

A successful technique of liver retransplantation in the rat is described. Heterotopic nonauxiliary liver engraftment of a whole liver using cuffed anastomoses is the primary transplant procedure. The graft is implanted in the right hypochondrium and is revascularized by a portal end-to-end anastomosis. Venous drainage is via an end-to-side anastomosis between the donor infrahepatic vena cava and recipient right renal vein. The graft suprahepatic vena cava is ligated. Biliary drainage is achieved by a double stent anastomosis of the biliary ducts. Total parenchymectomy of the recipient's liver is completed leaving intact the intrahepatic and suprahepatic vena cava. Retransplantation in the orthotopic position can thus be attempted, after removal of the first graft, by cuffed anastomoses between the donor and recipient portal veins, infrahepatic vena cava and a double stent anastomosis of the common bile ducts. Anastomosis between the donor and recipient suprahepatic vena cava is completed with a 7/0 Prolene running suture. In the first group of operations (n = 6), a three week survival rate of 50% after retransplantation was obtained. Using the technical lessons of these preliminary cases, 80% of the second group of operations (n = 5), were successful in the long term. Utilization of this new technique may allow further investigations in different fields of research dealing with liver surgery and transplantation.

Animals↗
PubMed1993

Protocol for the technique of orthotopic liver transplantation in the rat.

Orthotopic rat liver transplantation (OLT) has been generally accepted as an excellent model for the analysis of pathological, physiological, and immunological aspects related to organ transplantation. However, many researchers require a long training period to achieve a high success rate using this major surgical procedure on small animals. We therefore developed a protocol for learning rat OLT. It is recommended, initially, that the heterotopic heart transplantation (HHT) model be used to master the cuff technique, since this technique is similar to that in OLT and leads to an understanding of another organ transplantation technique. For beginners who advance beyond the HHT step to OLT but cannot finish the anhepatic phase within 30 min, we recommend the use of portosystemic-shunted rats as recipients. These animals have had their spleens transposed subcutaneously more than 3 weeks before use. The use of these modifications and this training program makes it possible to master the techniques and to achieve a high success rate with a short training period.

Animals↗
PubMed1993

Comparison of uptake of mitomycin C and KW-2149 by murine P388 leukemia cells sensitive or resistant to mitomycin C.

KW-2149, a new mitomycin C (MMC) derivative, inhibited the growth of murine P388 leukemia in vitro at 20-fold lower concentrations than those of MMC. KW-2149 was also effective in inhibiting the growth of MMC-resistant P388 (P388/MMC) cells. To elucidate these characteristics of KW-2149, its uptake and efflux were compared with those of MMC in MMC-sensitive and -resistant P388 cells. Both MMC and KW-2149 accumulated rapidly in P388 cells after incubation at the concentration of 0.47 and 0.024 microM, respectively, which were the IC50 values at 1-h exposure. Although this concentration of KW-2149 was 20 times lower than that of MMC, its intracellular concentration was little more than that of MMC, suggesting that KW-2149 accumulated in the cells quite efficiently. The accumulated KW-2149 in the cells after 1-h treatment remained for as long as 24 h after the incubation of the cells in drug-free medium, suggesting that most of the intracellular KW-2149 or MMC was bound to cellular components. The ratios of resistance of P388/MMC cells to MMC and KW-2149 were 34 and 8.8, respectively, at 1-h exposure, suggesting that P388/MMC cells were partially resistant to KW-2149 in vitro. P388/MMC cells also showed partial resistance to cisplatin, Adriamycin, m-AMSA, and etoposide. The accumulation of MMC in P388/MMC cells was lower than that in P388 cells, although the size of the former cells was almost equal to that of the latter. As a result, the amount of DNA-bound MMC was lower in P388/MMC cells than in P388 cells, suggesting its involvement in the mechanisms of MMC resistance in P388/MMC cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Small bowel transplantation in rats: endoscopic and histological evaluation of graft rejection.

Heterotopic small bowel transplantation was performed using the cuff technique in DA(RT1a) to PVG(RT1c) rat fully allogeneic combination. In this model, the rejection course of the grafted intestine was evaluated endoscopically via double stomata and was classified into four stages. Early changes appeared on postoperative day 3. Stage I: The mucosa of the grafted intestine showed patchy paleness and loss of the capillary fine network patterns, accompanied by microerosions. Closer examination revealed irregularity of the epithelial height and arrangement. Stage II: The damage spread progressively over the entire mucosa on day 4-5. Stage III: On day 6-7, the necrotic epithelium became detached, showing multiple ulcers which provoked hemorrhagic enteritis. Stage IV: Graft rejection was completed with total necrosis and white scar tissue formation by day 10-14. These endoscopic findings of the mucosa of the grafted intestine corresponded closely to the time course of pathological examinations. We conclude that endoscopic examination of grafted intestine may be an effective diagnostic tool to detect the rejection phenomenon at an early stage, as well as a simple tool to use for postoperative follow-up in combination with pathological examination.

Animals↗