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Biomedical subjects

H Kitamura

Publications and source records attributed to H Kitamura.

At least 55 records · Page 3Linked to original sources
PubMed2001

Spinal leptomeningeal metastases of giant cell glioblastoma associated with subarachnoid haemorrhage: case report.

A case of subarachnoid haemorrhage (SAH) due to spinal leptomeningeal metastases of a giant cell glioblastoma is described. A 51 year old male presented with a four week history of headache. Neurological examination was normal except for a slight left hemiparesis. Computed tomography (CT) revealed a large cyst with a mural nodule in the right temporal lobe. The tumour was removed followed by 60 Gy of radiation therapy. Thirty-two months later he developed headache and shoulder pain with symptoms of normal pressure hydrocephalus. Head CT showed ventriculomegaly and SAH. Magnetic resonance imaging showed spinal leptomeningeal metastases at the C4-5, T12, and L2 levels, but no local recurrence or tumour dissemination in the brain. He died 34 months after surgery. Autopsy revealed diffuse SAH over the whole brain and spinal cord, associated with spinal leptomeningeal metastases, but no cerebral aneurysms. Spinal radiotherapy and ventriculoperitoneal shunting could possibly have extended survival in this patient.

Brain Neoplasms↗
PubMed2001

Expression of cyclin-dependent kinase inhibitors in taste buds of mouse and hamster.

Taste buds are specialized epithelial cell clusters in the oral squamous cell epithelium. Although taste buds have been reported to renew rapidly, the mechanism of cell cycle control in these specialized structures remains unresolved. To clarify the cell cycle status and role of cyclin-dependent kinase inhibitors (CDKI) for cell cycle control in the taste buds, we analyzed cell proliferation activity using bromodeoxyuridine (BrdU) and Ki-67 immunostainings and the expression of the Cip/Kip family of CDKI (p21Cip1, p27Kip1, and p57Kip2) in the circumvallate papillae of mouse and hamster. BrdU-positive cells were detected in the basal layer of the oral epithelium. In the taste buds, Ki-67-positive cells were seen in the basal area, with only a very few positive cells in the taste buds. Both p21Cip1 and p27Kip1 positive cells were seen in the suprabasal layer of the non-gustatory oral epithelium. In the taste buds, stronger p27Kip1 staining was detected than in the non-gustatory epithelium. Western blotting analysis revealed that p27Kip1 was abundant in the mucosal tissues from circumvallate papillae. Thus, our study suggests that the taste bud cells except for basal cells are post-mitotic cells and that the cell cycle arrest associated with taste bud cell differentiation could be regulated predominantly by p27Kip1.

Animals↗
PubMed2001

Thymic carcinosarcoma consisting of squamous cell carcinomatous and embryonal rhabdomyosarcomatous components. Report of a case and review of the literature.

A case of thymic carcinosarcoma in an 83-year-old Japanese man is presented. He died of superior vena cava syndrome caused by a rapidly enlarged anterior mediastinum tumor eight months after initial symptoms. Autopsy revealed a 16 x 12 x 25 cm-sized, tan yellow, whitish tumor with a multinodular and microcystic appearance located in the left anterior mediastinum, which involved the residual thymus. The tumor had directly invaded the left pleura, and had metastasized to the right lung and spleen. Histologic examinations of the primary tumor showed a sarcomatous component consisting of racquet- or spindle-shaped cells with cross striations, and small nests of atypical squamous cells scattered throughout the tumor; neither transition between the two components nor intermediate cells with both epithelial and mesenchymal features was seen. Electron microscopic and immunohistochemical examinations confirmed the rhabdomyomatous differentiation of the sarcomatoid component. To our knowledge, there have been only two reported cases showing histologic features similar to the present tumor. For the histogenesis of thymic carcinosarcoma, we propose two hypotheses. The first is that sarcomatous cells are derived from carcinomatous cells by tumoral metaplasia. Secondly, that this type of tumor originates from thymic primitive cells with multidirectional differentiation potential. In accordance with the latter, we consider that the present tumor originated from thymic primitive cells. Thymic carcinosarcoma is a highly malignant tumor, and most patients die within a year. Appropriate therapies must be developed.

Aged↗
PubMed2001

Antioxidative activity of hydroxylamines. ESR spectra of radicals derived from hydroxylamines.

The antioxidative activity of hydroxylamines was evaluated for the oxidation of tetralin at 61 degrees C and linoleic acid micelles in an aqueous dispersion at 37 degrees C, induced by an azo initiator. The antioxidative efficacy of the hydroxylamines for the oxidation of tetralin was smaller than that of alpha-tocopherol. However, the hydroxylamines showed more potent antioxidative activity than that of the alpha-tocopherol against the oxidation of linoleic acid micelles. On the basis of the results of an ESR study and the oxidation product obtained, it is suggested that active position in hydroxylamines depend not only on hydroxyl hydrogen-atom, but also on the allylic hydrogen atom.

Antioxidants↗
PubMed2001

Pulmonary amyloidosis diagnosed by CT-guided transbronchial biopsy: a case report.

During a medical check-up, a nodular shadow was detected by chest X-ray in the right lower lung field of a 59-year-old man. On computed tomography (CT), the nodular lesion had a relatively well-defined, irregular margin. A fluoroscopy-guided bronchoscopic biopsy did not uncover any malignancy. Specimens from a subsequent CT-guided bronchoscopic biopsy revealed a pulmonary amyloid deposit. As a rule, it is difficult to exclude malignancy or confirm benign disease in cases of truly benign lesions, particularly if the lesions are difficult to biopsy. Amyloidosis is one of such conditions and requires reliable diagnostic methods to avoid unnecessary surgical resection. From our experience, we consider CT-guided bronchoscopic biopsy to be a safe and accurate procedure, even when applied to truly benign lesions.

Amyloidosis↗
PubMed2001

The three-dimensional architecture of retinal blood vessels in KK mice, with special reference to the smooth muscle cells and pericytes.

In the present study, the three-dimensional architecture of retinal vasculature was studied in KK mice, by combined use of resin injection, chemical treatment and scanning electron microscopy (SEM). In particular, Mercox/methylmethacrylate resin-injected eye tissues were subjected in sequence to NaClO immersion, ultrasonication and HCl treatment. The present technological innovation made possible SEM visualization of deeper retinal vasculature. In KK mice, the tunica media of stem arterioles and of first and second order branches consisted of a single layer of spindle-shaped smooth muscle cells provided with spine-like cytoplasmic processes. In addition, there occurred small triangular smooth muscle cells provided with slender cytoplasmic processes. The processes, giving off tiny secondary processes, overlapped with each other, thus forming assemblages around branching sites. Such a structure was particularly prominent for those branching sites where parent arterioles gave rise to their branches in a side arm-like pattern. The third (and occasionally fourth) order branches were surrounded by atypical smooth muscle cells, with considerable dimension of endothelial surface remaining uncovered. Capillary pericytes consisted of fusiform cell bodies and slender cytoplasmic processes. Smooth muscle cells of retinal venules differed from those of arterioles. They were stellate in shape, exhibiting several cytoplasmic processes.

Animals↗
PubMed2001

Differential dosimetry in a neutron-proton mixed field with low-pressure proportional counters.

For a mixed radiation field of neutrons and protons, radiation events were discriminated between photons, neutrons, and protons using a thin plastic scintillator. Distributions of lineal energy were measured with low-pressure proportional counters (LPPCs). To estimate the distribution of lineal energy for ICRU muscle, measurements were carried out using A-150-walled, graphite-walled, ZrO2-walled, and Zr-walled counters. Data were corrected for different atomic compositions between the A-150 plastic and ICRU muscle.

Energy Transfer↗
PubMed2001

Value of lipiodol computed tomography and digital subtraction angiography in the era of helical biphasic computed tomography as preoperative assessment of hepatocellular carcinoma.

OBJECTIVE: To compare the diagnostic accuracies of Lipiodol computed tomography (CT) and helical biphasic CT as preoperative imaging modalities for hepatocellular carcinoma (HCC). SUMMARY BACKGROUND DATA: Lipiodol CT after digital subtraction angiography has long been used as a highly sensitive imaging modality for HCC. The recent advent of helical CT has allowed scanning the entire liver during both the arterial and portal venous phase of contrast enhancement. METHODS: The authors analyzed data from 164 patients who underwent hepatic resection for HCC to calculate the sensitivity and specificity of these modalities. Findings of intraoperative ultrasonography followed by histologic confirmation were set as the gold standard. RESULTS: Although sensitivity decreased with both modalities as tumors became small and well differentiated, helical CT showed a higher sensitivity than Lipiodol CT in detecting well-differentiated HCC nodules smaller than 2 cm. In contrast, Lipiodol CT was superior to helical CT for the detection of small but moderately to poorly differentiated nodules. The overall sensitivity of helical CT was higher than that of Lipiodol CT. These findings suggest that helical CT is superior in delineating early HCC, whereas Lipiodol CT is specific to the detection of intrahepatic metastases. In terms of specificity, helical CT was superior to Lipiodol CT. CONCLUSIONS: Helical CT and Lipiodol CT are complementary modalities. At present, helical biphasic CT does not obviate the need for invasive techniques such as angiography and Lipiodol CT as preoperative examinations for HCC.

Adult↗
PubMed2001

Sole expression of laminin gamma 2 chain in invading tumor cells and its association with stromal fibrosis in lung adenocarcinomas.

Laminin-5 (LN-5), an important basement membrane (BM) protein consisting of laminin alpha3, beta3 and gamma 2 chains, has been suggested to be involved in tumor cell invasion and tissue repair. In this study, the distribution of the LN-5 subunits in atypical adenomatous hyperplasia (AAH) and different types of adenocarcinomas of the lung was examined by immunohistochemical analysis. In AAH and non-sclerosing, well-differentiated adenocarcinomas, the LN gamma 2 chain was frequently detected along with the continuous BMs. These BMs were also positive for both LN alpha3 and beta3 chains, suggesting that LN-5 had been deposited. In contrast, the cytoplasmic staining for the LN gamma 2 chain was frequently observed in tumor cells of sclerosing, well-differentiated adenocarcinomas, as well as of moderately and poorly differentiated adenocarcinomas, without any evidence of co-expression of the LN alpha3 and beta3 chains. This staining pattern of the LN gamma 2 chain was prominent in carcinoma cells invading into interstitial stroma and was associated with the formation of a central scar in the tumor tissues. These results suggest that the LN gamma 2 chain monomer could be an important indicator of progression of lung adenocarcinoma.

Adenocarcinoma↗
PubMed2001

A study of factors influencing prognosis after resection of hepatic metastases from colorectal and gastric carcinoma.

OBJECTIVE: The aim of this study is to determine the absolute contraindication for hepatic resection for colorectal metastases and investigate the value of hepatectomy for gastric metastases by comparing it with the results of colorectal metastases performed with the same criteria. METHODS: A retrospective cohort study was conducted in patients undergoing hepatic resection for metastatic colorectal (n = 64) and gastric (n = 17) carcinomas. Common predictive factors for both metastases were analyzed by the stratified Cox proportional hazard model. In this model, the different baseline hazard was set for each disease, whereas the risk of each covariate was assumed to be equal in both gastric and colorectal metastases. RESULTS: Overall 1-, 2-, and 5-yr survival rates after hepatectomy for colorectal and gastric metastases were 90%, 73%, 42%, and 47%, 22%, 0%, respectively. Factors controlling prognosis were as follows: age > or = 60, extrahepatic metastases, serosal invasion, grade of lymph node metastases, tumor cell differentiation of the primary lesion(s), carcinoembryonic antigen level, tumor-exposed surgical margin, and blood transfusion. In particular, presence of extrahepatic metastases showed the markedly high-risk ratio among these eight variables. CONCLUSIONS: Hepatectomy, if possible, is indicated in patients with hepatic metastases from colorectal carcinoma if there are no extrahepatic metastases and if the primary disease is controlled. It is indicated only in carefully selected patients with metastases from gastric carcinoma.

Adult↗
PubMed2001

Pancreatic islet regeneration by ephedrine in mice with streptozotocin-induced diabetes.

In this experiment, we investigated the effects of crude Ephedrae herba, alkaloid extract of Ephedrae herba and 1-ephedrine, a major alkaloid component, on diabetic mice induced by streptozotocin (STZ). The alkaloid extract and 1-ephedrine showed suppression on the hyperglycemia. The suppression by Ephedrae herba of hyperglycemia may therefore be due to 1-ephedrine. Furthermore, we found that Ephedrae herba, alkaloid and 1-ephedrine promoted the regeneration of pancreas islets following atrophy induced by STZ. It is therefore suggested that Ephedrae herba may regenerate atrophied pancreatic islets, restore the secretion of insulin, and thus correct hyperglycemia.

Animals↗
PubMed2001

Interaction of poly(2-acrylamido 2-methylpropane sulfonate)-grafted polystyrene beads with cationic complement proteins.

Influence of various biomaterials on the complement system in serum has been intensively studied by many research groups, since activation of the complement pathway in vivo has been known to give rise to some pathological conditions, such as inflammation and anaphylaxis. Much effort has been devoted to develop new materials that do not activate or deteriorate the complement system. The present work is aimed at revealing the mode of reactions of anionic poly(2-acrylamido 2-methylpropane sulfonate) grafted on polystyrene bead (PAMPS-g-bead) with serum complement. Complement activity assay, determination of complement proteins levels, and immunoblot analysis were carried out for sera pretreated with PAMPS-g-beads. The results clearly showed that, when PAMPS-g-beads were incubated with serum, those beads adsorbed several complement proteins, i.e. C1q, factor D, factor P, C6, and C8, but the generation of activation fragments of complement components was not observed. Especially, factor D was most effectively removed from serum, resulting in potential inhibition of the alternative pathway. A larger amount of PAMPS-g-beads was needed to decrease the serum CH50 level. That may be caused by removal of C6. Although some polyanions, such as dextran sulfate, were reported to activate the complement system, the obtained results indicate that the PAMPS-g-bead is not an activator of the complement pathway, but acts as an adsorbent of complement components. One possible clinical application of the PAMPS-g-beads is adsorption of serum factor D by extracorporeal treatment of patients with renal failure with a high level of factor D, because the increased quantity of factor D in serum may cause consistent activation of the alternative pathway.

Biocompatible Materials↗
PubMed2001

Tubulointerstitial injury of Thy-1 nephritis in uninephrectomized stroke-prone spontaneously hypertensive rats.

Thy-1 nephritis was induced in stroke-prone spontaneously hypertensive rats (SHR-SP) with unilateral nephrectomy (UNX) and normotensive same genetic strain Wistar-Kyoto (WKY) rats with UNX to evaluate whether the tubulointerstitial injury in Thy-1 nephritis is accelerated by long-term systemic and intraglomerular hypertension. SHR-SP that underwent UNX at twelve weeks of age were randomly assigned to receive monoclonal anti-thy 1.1 antibody (group SP), and normal saline (group SC). Age-matched normotensive WKY rats served as controls and were given the same dose of monoclonal anti-thy 1.1 antibody after UNX (group WK). In all groups, the blood pressure and renal function were assessed, and morphologic changes of tubulointerstitium were examined by using immunohistochemistry and light microscopy twelve weeks after Thy-1 nephritis induction (in groups SP and WK) and UNX alone (in group SC). In all groups, histological findings, the degree of monocyte/macrophage infiltration, interstitial expression of alpha-smooth muscle actin (alpha-SMA), which is a marker for myofibroblasts, and the degree of tubular cell proliferation were examined. In addition, assessments of blood pressure, serum creatinine and BUN levels, and the degree of proteinuria were made. In parallel to glomerular structural damage, interstitial fibrosis with predominant monocyte/macrophage influx, increased interstitial expression of alpha-SMA and tubular cell proliferation were observed in group SP. A significant increase in serum creatinine and proteinuria were also present in this group. In contrast, the changes observed in group SC were not so evident or extensive as in group SP. The level of proteinuria was lower than that in group SP. No evident tubulointerstitial changes were found in group WK. The results showed that tubulointerstitial injury was prominently progressed in the hypertensive model with Thy-1 nephritis. This suggests that sustained systemic and glomerular hypertension is not only ultimately responsible for the progression of immunologically mediated glomerular injury, but is also responsible for subsequent tubulointerstitial changes. Migration and proliferation of myofibroblasts and intense influx of monocytes/macrophages may contribute to the development of tubulointerstitial fibrosis.

Animals↗
PubMed2001

No alteration in serum leptin levels during acute endotoxemia in sheep.

To determine the role of leptin in endotoxin-induced anorexia in ruminants, circulating leptin levels were measured during acute experimental endotoxemia in sheep. Injection of bacterial lipopolysaccharide (450 ng/kg, i.v.) induced anorexia accompanied with fever and increases in serum levels of cortisol, insulin and glucose which are known to stimulate leptin secretion in rodent and human, while it did not affect serum leptin levels at all. These results indicate that serum leptin levels in sheep during acute endotoxemia are differentially regulated from those in rodent and human, and that leptin might not be involved in the endotoxin-induced anorexia in sheep.

Acute Disease↗
PubMed2001

Significance of proneural basic helix-loop-helix transcription factors in neuroendocrine differentiation of fetal lung epithelial cells and lung carcinoma cells.

In this brief review article, we describe how cell fate determination by which the airway epithelial cells become neuroendocrine or non-neuroendocrine is regulated by a network of basic helix-loop-helix transcription (bHLH) factors in a similar manner to neuronal differentiation, and how this system could work to determine cell differentiation of human lung carcinomas. Immunohistochemical studies reveal that mammalina achaete-scute complex homologue (Mash)1 is expressed in pulmonary neuroendocrine cells (PNEC), while hairy and Enhancer of split (Hes)1 is expressed in pulmonary non-neuroendocrine cells (non-PNEC). Studies using gene-deficient mice for the bHLH factors revealed that in Mash1 homozygous null mice no PNEC are detected, while PNEC increase markedly in Hes1 homozygous null mice. These observations suggest that Mash1 is an essential positive factor for neuroendocrine differentiation of lung epithelium, and that Hes1 is one of the repressive factors for neuroendocrine differentiation. Moreover, immunohistochemical studies revealed that Notch receptors are detected in non-PNEC, and thus the Notch signalling pathway could play a role in the determination of airway epithelial cell differentiation. In human lung carcinomas, a similar bHLH network should operate to determine cell differentiation phenotypes. Generally, expression of the human homologue of Mash1 (HASH1) is detected in small cell carcinoma and carcinoids, while Hes1 seems to be expressed mainly in non-small cell carcinoma. Thus, proneuronal bHLH factors may play roles in cell fate determination of the airway epithelial system, and may regulate human airway epithelial cells in diseased conditions.

Animals↗
PubMed2001

Hemolytic uremic syndrome with intracranial hemorrhage following mitomycin C administration.

A 50-year-old woman treated for breast cancer with mitomycin C developed severe hypertension, followed by deep coma 3 days later. Computed tomography of the brain showed frontoparietal intracranial hemorrhage accompanied by subarachnoid hemorrhage. The patient was diagnosed additionally with hemolytic uremic syndrome (HUS) based on hemolytic anemia with schistocytosis, thrombocytopenia, and acute renal failure. The patient underwent hemodialysis and plasmapheresis with no improvement. We present the pathologic findings of the general vessels, which has been reported rarely. This case represents the first reported intracranial hemorrhage in HUS following mitomycin C administration. We emphasize the need to control blood pressure in patients with HUS.

Alkylating Agents↗
PubMed2001

Identification of hepatic venous territories in liver resection by using color Doppler ultrasonography: report of two cases.

OBJECTIVE: Resection of the hepatic vein because of the proximity of tumors may result in increased congestion in the noncancerous parenchyma, which in turn may lead to functional hepatic volume loss and postoperative hepatic failure, especially in a case of low hepatic reserve. However, to our knowledge, no technique for estimating the extent of dependent hepatic venous territories before hepatic resection has been established. We examined the possibility of using color Doppler ultrasonography for this purpose. METHODS: A color Doppler system and a linear array transducer equipped with multiple Doppler frequencies ranging from 7 to 13 MHz were used intraoperatively. Two patients with hepatocellular carcinomas were examined. By tracking entire branches of the targeted vessel, from the trunk to the terminal branches extending to the liver surface, it was possible for the boundaries of the dependent areas to be projected and marked on the liver surface with either ink or electrocautery. RESULTS: In both cases, this method was effective for either minimizing the congestive area or preserving the hepatic mass that was being drained via aberrant routes. CONCLUSIONS: Identification of hepatic venous territories by means of color Doppler ultrasonography may provide new information about intrahepatic blood circulation and may increase the safety and curability of hepatic resection.

Aged↗