Biomedical subjects

H Ikeda

Publications and source records attributed to H Ikeda.

At least 487 records · Page 27Linked to original sources

PubMed1997

Early morphologic changes of atherosclerosis induced by ventromedial hypothalamic lesion in the spontaneously diabetic Goto-Kakizaki rat.

It is generally thought that typical atherosclerotic lesions do not develop in the rodent. The Goto-Kakizaki (GK) rat is a nonobese strain in which a spontaneous type of non-insulin-dependent diabetes mellitus develops without apparent macroangiopathy. In our previous study, making ventromedial hypothalamic (VMH) lesions in GK rats induced hyperphagia and a further deterioration in glucose metabolism. In the current study, male GK rats in which VMH lesions were made were examined for vascular changes, with special reference to atherosclerotic lesions. Marked hyperglycemia in GK rats with VMH lesions (hereafter referred to as VMH lesion rats) was revealed over an observation period (plasma glucose levels 16 weeks after the operation: VMH lesion GK rats, 19.3 +/- 2.0 mmol/L, vs sham-operated GK rats, 10.1 +/- 1.3 mmol/L; p < 0.0001). Light microscopic observation of the descending aorta in VMH lesion GK rats 16 weeks after the surgery revealed that the intimal thickening and the number of infiltrating cells into the intima were significantly increased as compared with sham-operated GK rats (17531 +/- 3747 microm2 vs 3072 +/- 1192 microm2, p < 0.0001; 15.6 +/- 3.1 per one transverse section vs 6.8 +/- 2.5 per one transverse section, p < 0.0005). Electron microscopic observations demonstrated an increased number of microvilli and lysosomes in endothelial cells, infiltration of macrophages and lymphocytes into the intima, and migration of medial smooth muscle cells into the intima that are considered to be early events in atherosclerosis. These morphologic changes could be induced by a deterioration in glucose metabolism. This rat may thus be useful for studying the process of the initiation of atherosclerosis in diabetes mellitus.

Animals↗

PubMed1997

A peculiar form of multiple cystic dilatation of the intrahepatic biliary system found in a patient with biliary atresia.

The authors report a peculiar form of intrahepatic multiple cysts of the biliary system in a patient with biliary atresia (BA). An 11-year-old girl was admitted to our institution to be investigated for repeated cholangitis occurring after the age of 10 years. She underwent a hepaticojejunostomy, caused by Type I (cyst-type) BA, in the neonatal period. The radiological examination results showed multiple cystic dilatation of the intrahepatic biliary system with a vascular structure protruding into the cyst lumen. Such cystic dilatation with a protruding vascular structure has been noted in patients with Caroli's disease and congenital hepatic fibrosis, and ductal plate malformation is shown to be responsible for the cyst formation. The authors postulate that such malformation of the intrahepatic biliary system is related to the cyst formation in our case.

Bile Ducts, Intrahepatic↗

PubMed1997

The relationship between disturbed transit and dilated bowel, and manometric findings of dilated bowel in patients with duodenal atresia and stenosis.

To determine whether dilated bowel proximal to obstruction associated with duodenal atresia and stenosis is related to feeding problems after a surgical correction of obstruction, the authors reviewed retrospectively the degree of bowel dilatation and disturbed transit as well as other clinical features in 18 duodenal atresia and 12 duodenal stenosis patients. A multivariate analysis was conducted to determine the possible correlation among them. The authors also evaluated the physiological function of the dilated bowel in duodenal atresia and stenosis patients (n = 8) by manometry of dilated bowel. The results were as follows. (1) In multivariate analysis, using the degree of disturbed transit as a dependent variable and using other clinical features as independent variables, the presence of postoperative complication and the existence of bowel dilatation 2 weeks after the operation were risk factors for disturbed transit. (2) One or two episodes of phase 3 were found in six of eight measured patients during the recorded period. The most distinctive manometric finding was the low contraction amplitude of both phase 2 and phase 3. These results indicate that dilated bowel was related to disturbed transit during the postoperative period, and that the low contraction amplitude of the dilated bowel was the main pathophysiological feature. The tapering or plication of dilated bowel might be indicated in patients with a markedly dilated bowel.

Constriction, Pathologic↗

PubMed1997

Association between hepatoblastoma and very low birth weight: a trend or a chance?

Hepatoblastoma, a malignant hepatic tumor in children, is thought to be an embryonal tumor resulting from developmental disturbances during organogenesis. Although factors that might be involved in the tumorigenesis have been suggested, an association between hepatoblastoma and the patient's birth weight has not been reported. We have accessed the data in the Japan Children's Cancer Registry and have analyzed patients' diagnoses and birth weights. During the 9 years from 1985 to 1993, 38 (0.38%) patients with tumors who weighted less than 1500 gm at birth were identified among 9923 registered patients. Hepatoblastoma was diagnosed in 9 patients of very low birth weight, representing 3.9% of the 231 patients with hepatoblastoma registered. A significant linear trend toward an increase in the percentage of patients with a birth weight of less than 1500 gm was observed specifically in hepatoblastoma (p = 0.0047). The percentage rose from 0.7% (1/138) in the 5-year period of 1985 to 1989 to 8.6% (8/93) in the next 4-year period (1990 to 1993). This increase was attributed to the significant increase in the percentage of patients who weighed less than 1000 gm at birth (p = 0.0028). A separate peak in the number of patients in the birth weight range of less than 1000 gm suggests that the cause of hepatoblastoma related to very low birth weight may be different from that of other patients. Full analysis of the patients' data is an urgent matter.

Birth Weight↗

PubMed1997

Antisense oligodeoxynucleotide to delta opioid receptors blocks cocaine-induced place preference in mice.

The effect of intracerebroventricular (i.c.v.) treatment with antisense oligodeoxynucleotide (A-oligo) to delta opioid receptor mRNA on cocaine-induced place preference was examined in mice. Cocaine (10 mg/kg, s.c.) produced a significant place preference. I.c.v. treatment with A-oligo (0.001-1 microg/mouse) dose-dependently attenuated the cocaine (10 mg/kg, s.c.)-induced place preference, although mismatched oligodeoxynucleotide (1 microg/mouse, i.c.v.) was ineffective. In the present study, we found that the selective reduction in number and/or function of central delta opioid receptors by A-oligo suppresses the cocaine-induced place preference. These results suggest that the conditioned reward by cocaine may be partially mediated by central delta opioid receptors.

Animals↗

PubMed1997

Effects of neurotropic pyrimidine heterocyclic compound, MS-430, on cultured hepatic parenchymal and stellate cells.

MS-430 is a novel synthetic pyrimidine derivative that stimulates regeneration of the nerve as a promoter for various growth factors such as epidermal growth factor (EGF) and nerve growth factor, and differentiation of astrocytes. The effects of MS-430 on the liver were tested using hepatocytes and stellate cells in primary culture isolated from rats. MS-430 enhanced EGF-induced DNA synthesis in hepatocytes while it alone failed to increase the basal DNA synthesis. Albumin mRNA expression in the cells and its amount in the medium were not changed by addition of EGF or MS-430 alone or both. Basic fibroblast growth factor (bFGF) increased DNA and but not collagen synthesis by hepatic stellate cells. Addition of MS-430 inhibited DNA synthesis by hepatic stellate cells at either presence or absence of bFGF, and collagen synthesis at the presence of bFGF. However, MS-430 had no effects on basal or bFGF-stimulated TGFbeta mRNA expression in the cells. These results suggest that MS-430 stimulated proliferation of hepatocytes as a comitogen for EGF without affecting albumin synthesis, and suppressed proliferation of activated hepatic stellate cells and their collagen synthesis without affecting TGFbeta expression.

Animals↗

PubMed1997

Antisense oligodeoxynucleotide to delta opioid receptors attenuates morphine dependence in mice.

The effect of intracerebroventricular (i.c.v.) treatment with antisense oligodeoxynucleotide (A-oligo) to delta opioid receptor mRNA on the morphine-induced place preference and naloxone-precipitated jumping was examined in morphine-dependent mice. Morphine (5 mg/kg, s.c.) produced a significant place preference. I.c.v. pretreatment with A-oligo (0.01-1 microg/mouse) dose-dependently attenuated this morphine (5 mg/kg, s.c.)-induced place preference, while mismatched oligodeoxynucleotide (M-oligo; 1 microg/mouse, i.c.v.) was ineffective. Naloxone (3 mg/kg, s.c.) precipitated jumping in morphine-dependent mice. I.c.v. pretreatment with A-oligo (1 microg/mouse) attenuated this naloxone (3 mg/kg, s.c.)-precipitated jumping in morphine-dependent mice, while M-oligo (1 microg/mouse, i.c.v.) was ineffective. These data demonstrate that the selective reduction in supraspinal delta opioid receptor function caused by pretreatment with A-oligo attenuated the morphine-induced place preference and naloxone-precipitated jumping in morphine-dependent mice, suggesting that the rewarding effect of and physical dependence on morphine may be modulated by central delta opioid receptors.

Animals↗

PubMed1997

Fractionated stereotactic radiotherapy for choroidal melanoma.

Stereotactic radiotherapy used for the treatment of choroidal melanoma made use of a 6-MeV linac with built-in multileaf collimators and a simple plastic head mold. The latter provided excellent head and ocular immobilization. The system resulted in highly localized dose distributions with a maximum 2-mm targeting error during fractionated treatments. Based on these techniques, sixteen patients with choroidal melanoma have so far been treated. Majority of patients received a total dose of 48 Gy in 8 fractions. Fourteen patients who presented with small- to moderate-sized tumors have remained free of relapse or major complications during the follow-up period of 3-42 months. Two patients who presented with an extensive tumor eventually required enucleation after irradiation. Technical precision required for stereotactic radiotherapy and reproducibility for fractionation appear adequate. Encouraging preliminary results justify further studies to evaluate its efficacy as an alternative to other conventional therapeutic approaches.

Adult↗

PubMed1997

Isolated dural metastasis from colon cancer.

We report a case of isolated dural metastasis from colon cancer. Neuroradiologic and intraoperative findings indicated that the tumor was extra-axial, and histopathologic examination resulted in the correct diagnosis. Notable neuroradiologic findings of the present dural-based tumor were: diploic fat MRI signal disappeared in the tumor associated calvaria where bony change was absent on bone-window CT; abnormal subgaleal and epidural tissues were seen on MRI, both of which contained clusters of adenocarcinoma cells histopathologically. These findings suggest an infiltrative, malignant character, and help to differentiate between benign and malignant dural-based tumors.

Adenocarcinoma↗

PubMed1997

Interleukin-1 beta converting enzyme (ICE) is preferentially expressed in neuroblastomas with favourable prognosis.

To determine whether interleukin-1 beta converting enzyme (ICE) plays a role in the programmed cell death of neuroblastoma, we studied ICE expression in primary tumours. In patients in stages I, II and IVS, ICE mRNA was detected in 22 of 32 (69%) tumours, while only 5 of 26 (19%) tumours expressed ICE in stages III and IV (P < 0.001). ICE mRNA was expressed in 27 of 47 (57%) tumours without MYCN amplification, but it was not detected in any tumours with MYCN amplification (P < 0.01). Immunohistochemically, the cytoplasm was stained in all 15 neuroblastomas examined. The nuclei were stained in 12 neuroblastomas without MYCN amplification, whereas only 1 of 3 tumours with MYCN amplification had positive staining in the nuclei. In ganglioneuromas, high levels of ICE mRNA were expressed, but immunostaining showed that the protease expression was confined to the cytoplasm. These observations suggest that ICE may be associated with the spontaneous regression often seen in favourable neuroblastomas and that localisation of ICE protease in the cell may be important for the cell death pathway. Double staining for ICE and TUNEL showed that they were co-localised in some nuclei, but the distribution of ICE protease expression was not necessarily the same as that of DNA fragmentation, suggesting that the protease expression probably preceded DNA fragmentation during the apoptotic process. ICE may play an important role in regulating the apoptotic process of neuroblastoma.

Blotting, Northern↗

PubMed1997

Characterization of an antigen that is recognized on a melanoma showing partial HLA loss by CTL expressing an NK inhibitory receptor.

Melanoma lines MEL.A and MEL.B were derived from metastases removed from patient LB33 in 1988 and 1993, respectively. The MEL.A cells express several antigens recognized by autologous cytolytic T lymphocytes (CTL) on HLA class I molecules. The MEL.B cells have lost expression of all class I molecules except for HLA-A24. By stimulating autologous lymphocytes with MEL.B, we obtained an HLA-A24-restricted CTL clone that lysed these cells. A novel gene, PRAME, encodes the antigen. It is expressed in a large proportion of tumors and also in some normal tissues, albeit at a lower level. Surprisingly, the CTL failed to lyse MEL.A, even though these cells expressed the gene PRAME. The CTL expresses an NK inhibitory receptor that inhibits its lytic activity upon interaction with HLA-Cw7 molecules, which are present on MEL.A cells and not on MEL.B. Such CTL, active against tumor cells showing partial HLA loss, may constitute an intermediate line of anti-tumor defense between the CTL, which recognize highly specific tumor antigens, and the NK cells, which recognize HLA loss variants.

Amino Acid Sequence↗

PubMed1997

Molecular analysis of p21 and p27 genes in human pituitary adenomas.

Pituitary tumours develop at a high frequency in p27-knockout mice and retinoblastoma gene-knockout mice, which suggests that cell cycle regulatory genes, such as cyclin-dependent kinase inhibitor genes, are involved in the tumorigenesis of pituitary adenoma. Analysis of p21 and p27 gene abnormalities in human pituitary adenoma was performed in 28 pituitary adenomas by polymerase chain reaction-single-strand conformational polymorphism. No point mutations were detected in these genes. As no abnormalities of the p21 and p27genes were observed, and if these genes are indeed inactivated, it is likely to be via transcriptional or translational defects.

Adenoma↗

PubMed1997

Clinico-pathological study of Cushing's disease with large pituitary adenoma.

OBJECTIVE: To explore the biological and morphological differences between large Cushing's adenomas and small adenomas, we investigated the clinical, endocrinological, neuroradiological, and histological features of patients with large Cushing's adenomas and compared them with patients with small Cushing's adenomas. PATIENTS: Five of 250 patients with Cushing's disease undergoing trans-sphenoidal operations from 1989 to 1995 had large adenomas with maximum diameters greater than 30 mm. The clinical characteristics of these five patients were compared with the 14 patients with Cushing's disease with small adenomas in our series. RESULTS: Oedema, myopathy, and mental disturbance were more frequent and hypertension was less frequent among patients with large adenomas. The high-dose (8 mg) dexamethasone test did not suppress cortisol production in any of the five patients. Invasion into surrounding tissue was demonstrated by magnetic resonance imaging in all five cases. All five large adenomas had scarce or no periodic acid-Schiff-positive granules and were sparsely granulated ultrastructurally. Three tumours contained cells with honeycomb Golgi apparatus which rarely contained immature secretory granules. One Crooke's cell adenoma contained trapped or displaced secretory granules. The other tumour had dilated trans-Golgi network-derived vacuoles that contained reticular or circular electron-dense material. These findings were in striking contrast to those of small Cushing's adenomas, which showed strong PAS positivity, densely-packed granulation, and had prominent Golgi complex harbouring developing secretory granules. CONCLUSIONS: We found that the tumour cells in large adenomas produced only small amounts of ACTH, and showed indications of disturbances in the regulated exocytotic pathways. These factors may account for the different clinical characteristics of Cushing's disease with large pituitary adenomas.

Adenoma↗

PubMed1997

Symptomatic hypophyseal granular cell tumour: endocrinological and clinicopathological analysis.

We report a case of a hypophyseal granular cell tumour (GCT) presenting with visual failure and hyperprolactinaemia (serum prolactin level, 274 ng/ml; normal, < 10). Magnetic resonance images demonstrated an intrasellar mass with anterosuperior extension. As the patient had chronic renal failure (CRF) and hyperprolactinaemia is frequent in CRF patients, a firm preoperative diagnosis of prolactinoma could not be made. Transsphenoidal removal of the tumour resulted in improvement of both vision and serum prolactin. Histopathological analysis of the surgical specimen revealed GCT. A cell kinetic study, the first such report for this type of tumour, revealed a relatively high Ki-67 staining index of 3.2%. On electron microscopy, numerous intracytoplasmic granules with various electron densities were demonstrated. Moreover, cell-processes extending from the granule-rich cytoplasm contained intracytoplasmic filaments but few granules, suggesting that the filament-rich cells, which are occasionally seen in GCT tissues, are essentially identical to the granule-rich cells in origin.

Diagnosis, Differential↗

PubMed1997

A wide spectrum of collagen vascular and autoimmune diseases in transgenic rats carrying the env-pX gene of human T lymphocyte virus type I.

To investigate the pathogenesis of human T lymphocyte virus type I (HTLV-I)- related diseases, the env-pX gene of HTLV-I was introduced into the germline of inbred Wistar-King-Aptekman-Hokudai rats. A wide spectrum of collagen vascular diseases was evident in the transgenic rats, including chronic destructive arthritis similar to rheumatoid arthritis, necrotizing arteritis mimicking polyarteritis nodosa, polymyositis, myocarditis, dermatitis, and chronic sialoadenitis and dacryoadenitis resembling Sjögren's syndrome in humans. Thymic atrophy with the depletion of CD4 and CD8 double-positive thymocytes was also observed. In these animals, a number of autoantibodies, including high titers of rheumatoid factor, were present in the serum. We propose that the HTLV-I env-pX gene region may play a pathogenetic role in the development of collagen vascular and autoimmune diseases associated with autoimmune phenomenon.

Animals↗

PubMed1997

Technical considerations for fractionated stereotactic radiotherapy of hepatocellular carcinoma.

Technical aspects of fractionated stereotactic radiotherapy for solitary hepatocellular carcinoma have been investigated. Precise positioning of the patient and substantial reduction of the liver movement due to respiration were achieved by placing the patient ventrally on the treatment couch without a body cast. Repeated CT examinations were required for verification of tumor targeting. Though there were geometrical limitations on gantry rotation when the linac couch was rotated from its standard position, dose distributions obtained were found to be excellent. A patient with a small solitary lesion in the posterior segment of the liver received 52 Gy in 13 fractions over 29 days. He tolerated the treatment well without experiencing any morbidities or deterioration of liver functions. Three months later his alpha-fetoprotein value returned to normal and CT examinations revealed tumor shrinkage as well as a reduction in the viability of the tumor cells. The results suggest that it is possible to overcome technical difficulties associated with fractionated stereotactic radiotherapy of intraabdominal tumors.

Aged↗

PubMed1997

A case of intravascular papillary endothelial hyperplasia (Masson's tumor) arising from renal sinus.

A 55-year-old woman had a right renal tumor incidentally diagnosed by ultrasonography. CT revealed a perirenal low density mass 3 cm in diameter. Dynamic CT showed peripheral enhancement of the tumor in early phase and internal homogeneous enhancement in delayed phase. Since hemangioma was considered most likely, we performed tumor resection and spared the right kidney. The tumor was supplied by the superior ureteral artery from the right main renal artery which was considered to be derived from the renal sinus. The tumor was diagnosed as intravascular papillary endothelial hyperplasia (Masson's tumor). This is the first report of intravascular papillary endothelial hyperplasia existing in the perirenal space. Although preoperative diagnosis of intravascular papillary endothelial hyperplasia is difficult, intra-operative pathology and kidney-sparing treatment should be considered in such a case.

Diagnosis, Differential↗

PubMed1997

Dietary soybean protein increases insulin receptor gene expression in Wistar fatty rats when dietary polyunsaturated fatty acid level is low.

To investigate the effects of different dietary fatty acids and proteins on glucose tolerance and insulin receptor gene expression, Wistar fatty rats (genetically obese, noninsulin-dependent diabetes mellitus) and their lean littermates (8 wk old) were fed a casein or soybean protein diet containing 9% partially saturated beef tallow (plus 1% corn oil), 10% corn oil or 10% fish oil for 3 wk. In glucose tolerance tests, plasma insulin concentrations were significantly higher in obese rats fed corn oil or fish oil than in those fed partially saturated beef tallow, particularly in the soybean protein groups. However, plasma glucose concentrations were not significantly affected by dietary protein or fat. The insulin receptor mRNA concentrations in livers and adipose tissues were higher in rats fed soybean protein/partially saturated beef tallow than in those fed any other protein/fat combination. Dietary soybean protein may help to reduce the insulin resistance, but only when a diet low in polyunsaturated fatty acids is consumed. On the other hand, the insulin receptor mRNA concentrations in adipose tissue were generally lower in the obese rats of all dietary groups than in the lean rats, suggesting that insulin resistance may be due to a defect of insulin receptor gene expression.

Animals↗