Biomedical subjects

K Kawamoto

Publications and source records attributed to K Kawamoto.

At least 91 records · Page 5Linked to original sources

PubMed1996

Matrix metalloproteinase-9 secretion by human pituitary adenomas detected by cell immunoblot analysis.

Twenty-two pituitary adenomas were examined on the secretion of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) using a cell immunoblot assay, and discussed regarding an association between cavernous sinus invasion and the secretion of these proteins. The cell immunoblot assay, a kind of immunoblot procedure, is able to detect proteins at the single cell level and to detect the incidence of tumour cells secreting the target proteins in the total tumour cell population. The incidence of tumour cells secreting MMP-9 was significantly higher in invasive adenomas than in noninvasive ones. On the other hand, TIMP-1 secretion was not detected in any adenomas in this study. This result suggested that MMP-9 secretion, and especially the number of MMP-9-secreting cells, may be associated with cavernous sinus invasion of pituitary adenomas.

Adenoma↗

PubMed1996

Type IV collagenase activity and cavernous sinus invasion in human pituitary adenomas.

Pituitary adenomas are regarded generally as benign tumours, but some of them can invade the cavernous sinus. On the other hand, matrix metalloproteinase-9 (MMP-9), which is a type IV collagenase, recently has been found to be expressed in matastases and to be related to the invasiveness of various malignant tumours including brain tumours. In order to investigate some characteristic features of pituitary adenomas which invade the cavernous sinus, we examined immunohistological studies for MMP-9 in seven pituitary adenomas for type IV collagen in a dura mater and assayed for type IV collagenase activity in seven adenomas using type IV collagen labelled with fluorescein isothiocyaniate (FITC). We found immunopositive adenoma cells for MMP-9 in all invasive adenoma and immunopositive spindle like cells for type IV collagen in the dura mater. All three invasive adenomas had high levels of type IV collagenase activity (0.57-0.72 U/ml), but the four adenomas which did not invade the cavernous sinus had low levels of type IV collagenase activity (0.0-0.10 U/ml). These results suggest that the level of type IV collagenase activity in a pituitary adenoma may be related to its ability to invade the cavernous sinus.

Adenoma↗

PubMed1996

Paraquat causes S-phase arrest of rat liver and lung cells in vivo.

We examined the in vivo effect of paraquat on the cell cycle in rat liver and lung tissues and the protective effect of tungsten (a xanthine oxidase inhibitor) on paraquat toxicity. The bromodeoxyuridine/propidium iodide double-staining method and flow cytometry were used for cell cycle assessment. Wistar rats were fed a standard diet or a tungsten-enriched diet were injected intravenously with 20 mg/kg paraquat, while uninjected rats served as controls. At 1, 3, and 5 days after paraquat injection, the liver and lungs were removed for examination following in vivo labeling with 20 mg/kg bromodeoxyuridine for 1 h. Liver and lung cells were isolated and incubated with an anti-bromodeoxyuridine antibody and with propidium iodide for DNA staining. Flow cytometry showed that the S-phase cell populations in the liver and lungs of paraquat-injected rats fed a standard diet were increased markedly on days 1 and 3 after injection compared with the control levels. However, on day 5 the liver cells had nearly returned to normal, while the S-phase population remained high in the lungs. In contrast, the S-phase cell populations of liver and lung tissue showed no increase after paraquat injection in rats fed a tungsten-enriched diet. These findings suggest that paraquat-induced cytotoxicity is more prolonged in the lungs than in the liver. In addition, paraquat toxicity appears to be mediated by xanthine oxidase and xanthine oxidase inhibitors may be useful an an antidote.

Animals↗

PubMed1996

Neuronal and glial characteristics of central neurocytoma: electron microscopical analysis of two cases.

We have identified two central neurocytomas which contained cells co-expressing glial fibrillary acidic protein and synaptophysin defined by double-label immunostaining. Dual-positive cells were mostly polygonal in shape and with a morphological appearance similar to that of reactive astrocytes. This distinct morphology could be used to distinguish cells expressing glial fibrillary acidic protein from cells with round and clear cytoplasm which did not express glial fibrillary acidic protein and which composed the majority of the tumor. Samples containing polygonal cells were selected for electron microscopy from toluidine blue-stained semithin sections. Ultrastructural findings were similar in both neurocytomas, with both being composed predominantly of round cells with clear cytoplasm corresponding to the clear cells identified by light microscopy. Dense-core vesicles and clear vesicles were frequently observed in the cell processes. Apart from these clear cells, polygonal cells with electron-dense cytoplasm were noted. Paralleling the result of double immunostaining, these polygonal cells contained both dense-core vesicles and intermediate, presumably glial filaments. Microtubules and lipofuscin granules were also observed. These results suggest that cells expressing glial fibrillary acidic protein in central neurocytoma include tumor cells with both neuronal and glial characteristics.

Adult↗

PubMed1996

Experimental studies of the antitumor effect of TNP-470 on malignant brain tumors. Antitumor effect of TNP-470 on a human medulloblastoma xenograft line.

It has been shown that angiogenesis plays an important role in pathological conditions including the growth of solid tumors. Furthermore, it is thought that anti-angiogenic agents might be clinically useful for therapy of these diseases. TNP-470 (TNP), a synthetic analog of fumagillin isolated from Aspergillus fumigatus, was used as an anti-angiogenic agent in this study in a nude mouse model with a subcutaneously implanted fragment of medulloblastoma. After treatment with this agent for 4 weeks, the inhibition rates of tumor growth were as follows: 15.9% in the group given 1 mg/kg, 16.9% with 10 mg/kg, 29.6% with 30 mg/kg, 49.9% with 50 mg/kg and 65.7% with 100 mg/kg. TNP inhibited the growth of brain tumor dose-dependently and induced various ischemic changes within the tumor tissue. Therefore, TNP may be effective for the treatment of malignant brain tumors such as medulloblastoma.

Animals↗

PubMed1996

Cementless total hip arthroplasty with autologous bone grafting for hip dysplasia.

The fate of autologous femoral head bone grafts in acetabular roof reconstruction for severely dysplastic hips was investigated in 25 patients (25 cementless total hip arthroplasties). Twenty patients were women and 5 were men, whose average age was 55 years old; their average followup was 58 months. The average Harris Hip Rating improved from a preoperative value of 49 points to a postoperative value of 85 points. Radiographic measurements did not indicate any vertical or horizontal socket migration >2 mm. The grafted bone was incorporated by an average time of 7 months, and the acetabular sclerosis had disappeared in 23 hips by 9.4 months. One year after operation, the grafted bone was reduced in size significantly. Radionuclide uptake at the site of the bone graft remained high for as long as 18 months after the operation, then normalized. The autologous acetabular bone grafts were incorporated completely and remodeled 18 months after surgery.

Acetabulum↗

PubMed1996

Twenty years' followup of intertrochanteric osteotomy for treatment of the dysplastic hip.

A followup study of more than 15 years of intertrochanteric osteotomy for osteoarthrosis of the dysplastic hip was performed in 52 hips of 42 patients with varus osteotomy and in 58 hips of 53 patients with valgus osteotomy. Varus osteotomy was indicated for predegenerative or early degenerative stages of osteoarthrosis, and valgus osteotomy was indicated for progressive or end stage disease. The average age at time of varus and valgus osteotomies was 25 and 37 years, respectively, and the average followup period was 21 and 20 years, respectively. Using Kaplan-Meier's method (end point, Harris Hip Score < 70 points or salvage operation), the 10- and 15-year survival rates for varus osteotomy were 89% and 87% and for valgus osteotomy were 66% and 38%, respectively. Radiographic measurements of the postoperative acetabular head index and center edge angle in varus osteotomy were better in the group with good results than those in the group with poor results. There were no differences in radiographic measurements between the group with good results and the group with poor results of valgus osteotomy. Intertrochanteric varus and valgus osteotomy delayed the need for total hip arthroplasty in young patients with osteoarthrosis of the dysplastic hip.

Adolescent↗

PubMed1996

Signal hyperintensities on brain magnetic resonance imaging in elderly depressed patients.

In a retrospective brain magnetic resonance imaging study, we evaluated the prevalence and severity of signal hyperintensities in 30 elderly depressed patients and 30 controls matched for age, sex and cerebrovascular risk factors. A semiquantitative scoring method was used to grade findings in T2-weighted and proton density images. The elderly depressed patients had more extended periventricular hyperintensities, especially in the frontal region (depressed vs. control, 87 vs. 57%, p < 0.05), pons (33 vs. 7%, p < 0.05) as well as hyperintensities in the putamen and globus pallidus (57 vs. 27%, p < 0.05). The third ventricle was more dilated in depressed patients than controls after adjustment for age and cerebrovascular risk factors. The global index for ventricular enlargement was correlated significantly (r = 0.36, p < 0.05) with the severity of the hyperintensity in depressed patients. Our results indicate that these hyperintensities, especially in the frontal region, pons and lenticular nuclei, and the dilatation of the third ventricle play an important role, through the frontal-subcortical circuits, in mood regulation of elderly depressed patients.

Aged↗

PubMed1996

Localization of HPC-1/syntaxin 1 in developing rat cerebellar cortex.

In adult rat cerebellum, HPC-1/syntaxin 1 is detected at high density on the plasma membrane of the non-synaptic region of parallel fibers in addition to the synaptic terminal membranes and the synaptic vesicles (Koh, S., Yamamoto, A., Inoue, A., Inoue, Y., Akagawa, Y., Kawamura, Y., Kawamoto, Y., and Tashiro, Y. (1993). J. Neurocytology 22: 995-1005). To assess the possibility that HPC-1/syntaxin 1 participates in the morphogenesis of the nervous system, we examined changes in the localization of HPC-1/syntaxin 1 during postnatal development of the molecular layer of the rat cerebellum. HPC-1/syntaxin 1 appeared in the granule cells in the outer granule cell layer in 3-days-old rat cerebellum when the formation of synapses and the appearance of a synaptic vesicle protein, synaptophysin, had not yet been observed in the molecular layer. At this stage, the granule cells began to form parallel fibers. Confocal laser microscopy and immuno-electron microscopy showed that HPC-1/syntaxin 1 was localized on the extruding plasma membrane of the granule cells to form parallel fibers. In 8-days-old rats, synapses formed between the parallel fibers and the developing dendrites of Purkinje cells, and the HPC-1 immunoreactivity appeared on the axons of parallel fibers and on the synapses. In 21-days-old rats, the HPC-1/syntaxin is involved in the formation of the molecular layer, especially in the axonal growth of the parallel fibers.

Animals↗

PubMed1996

Hemifacial dismasking flap for anterior skull base tumor--technical note.

A new approach to malignant tumor in the anterior skull base using a hemifacial dismasking flap is described. A bicoronal incision is extended unilaterally down to the neck, degloving the craniofacial tissue to widely expose the skeleton underneath, allowing easy resection of an extensive tumor without postoperative scarring of the face. This method has been used successfully on five patients.

Adenocarcinoma↗

PubMed1996

Surveillance system of infectious diseases in Japan.

The surveillance system of infectious disease in Japan started in 1981 and has been providing useful epidemiological information on 27 communicable diseases. The system consists of medical institutions (fixed monitoring stations), institutions of hygienic sciences, health centers, local governments and the ministry of health and welfare. There are two types of information about infectious diseases. One is clinical reports of incidence cases from medical institutions, and the other is laboratory information about etiologic agents. Between health centers, local governments and the department of statistics and information in the ministry of health and welfare, information is transmitted through the on-line network. Collected information is analyzed and submitted by both local and central committees of analysis. From the epidemiological point of view, quality control of the data and integration of other sources of data would be the next goal of the system.

Databases, Factual↗

PubMed1996

Immunohistochemical observation of foci of muscle actin-positive tumor cells in meningiomas.

OBJECTIVE: It has been suggested that muscle actin is expressed in some meningiomas. The purpose of this study was to examine this hypothesis in a large number of meningiomas and to examine possible explanations for this expression. DESIGN: Sixty-five meningiomas were examined using immunohistochemistry for muscle actin. Meningiomas with foci of muscle actin-positive cells (n = 6) were further examined using monoclonal antibodies for desmin, epithelial membrane antigen, cytokeratin, and von Willebrand factor. These specimens were also stained for reticulin. SETTING: All tissues were obtained from surgical biopsy specimens at a large academic medical center. MAIN OUTCOME MEASURES: Meningioma cells were considered to express muscle actin if the expression was shown to localize specifically in meningothelial cells and whorls that were also positive for epithelial membrane antigen. RESULTS: Seventeen of 65 meningiomas were shown to contain muscle actin-positive cells. Scattered cells were positive in 11 cases, and in the remaining six cases we observed foci of muscle actin-positive cells, which had a propensity to form cellular whorls. These foci expressed epithelial membrane antigen, but stains for desmin, cytokeratin, von Willebrand factor, and reticulin were negative. CONCLUSIONS: Our findings suggest that meningioma cells elaborate muscle actin without showing differentiation into specific cell types.

Actins↗

PubMed1996

Analysis and classification of nasopharyngeal electroencephalogram in "brain death" patients.

Nasopharyngeally-derived electroencephalogram (EEG) was recorded and digitized in 12 "brain death" subjects with flat-line scalp EEG and loss of auditory brain stem response. The nasopharyngeal EEGs of these cases were classified into three types: Type Ia with complete flat-line, Type Ib with almost but incomplete flat-line EEG, and Type II with low-amplitude slow fluctuations. Digitization of the nasopharyngeal EEG showed that equivalent electric potentials in low frequency bands (delta and/or theta 1) remained within the values of healthy volunteers in Types Ib and II. These results suggested that the tissue in or around the brain stem still functioned in Type 1b and II "brain death" patients. The origin of nasopharyngeal EEG was also discussed in this paper.

Adolescent↗

PubMed1996

[The operation for malignant tumors in the frontal skull base: combined transbasal & transfacial approach].

The authors have previously reported on an extensive transbasal approach, through which a supraorbital bar is osteotomized. This operative technique has been applied by the authors not merely to benign but also to malignant tumors in the frontal skull base. However, in the operation for malignant tumors of the frontal base, it is important to resect en-bloc the tumors and surrounding tissues, such as dura of the skull base and the orbital contents. The authors describe the operative mode of the combined transbasal & transfacial approach and its good results in 19 cases with malignant tumors in the frontal skull base, and 3 types of en-bloc resection in this operative approach (from type A to C) are introduced. Type A of en-bloc resection in the combined transbasal & transfacial approach was performed in 11 cases with the tumors invading the ethmoid sinuses. Type B was performed in 4 cases with tumors extending to the orbit. Type C was performed in 4 cases with tumors extending to the orbit and the maxillary sinuses on the affected side. These operative modes are useful in skull base surgery.

Adult↗

PubMed1996

[A case of bilateral MALT (mucosa-associated lymphoid tissue) type conjunctival malignant lymphoma].

A case of bilateral MALT (mucosa-associated lymphoid tissue) type conjunctival malignant lymphoma is reported. The patient, a 32 year old female, was referred to our hospital with the diagnosis of allergic conjunctivitis. We performed histopathological, immunohistochemical, and molecular genetical examination. The histopathological findings showed proliferation of CCL (centrocytelike) cells, lymphoepithelial lesion, and follicular colonization. Monoclonality of the tumor cells was revealed by molecular genetical analysis. On the basis of these detailed examinations, the patient was diagnosed as having MALT type malignant lymphoma. MALT type malignant lymphoma was first described by Isaacson in 1983. Both histological and clinical features are characteristic and quite different from other lymphomas. Some patients are affected bilaterally. Immunohistochemical and molecular genetical examinations in MALT type malignant lymphomas were found to be useful.

Adult↗

PubMed1996

Oesophageal cancer coexisting with colorectal lesions.

OBJECTIVE: To investigate the incidence of colorectal lesions in patients who present with oesophageal cancer. DESIGN: Prospective open study. SETTING: University hospital, Japan. SUBJECTS: 135 of 218 patients who presented with squamous cell carcinoma of the oesophagus during the seven year period 1988-1994 were randomly allocated to have a barium enema examination. INTERVENTIONS: Barium enema examinations, and if colorectal lesions were found, colonoscopy and biopsy. MAIN OUTCOME MEASURE: Incidence of coexistent colorectal lesions. RESULTS: No abnormal findings were found in 52 (39%), diverticula were present on 37 (27%), benign polypoid lesions in 51 (38%), and malignant lesions in 6 (4%). We examined the clinical and histopathological details of all patients to see if it was possible to distinguish the patients at high risk of developing oesophageal and colorectal cancer but could find no differences among the groups. CONCLUSION: Asymptomatic colorectal lesions are relatively common in patients with squamous cell carcinoma of the oesophagus in Japan.

Aged↗

PubMed1996

[Mechanism of cisplatin and peplomycin therapy on head and neck carcinoma].

Results of chemotherapy for head and neck cancer are now improving owing to the development of concomitant use of chemotherapeutic agents such as cisplatin or peplomycin. Concomitant use of the two agents has been favored clinically. However, fundamental study on the combination therapy has not been carried out sufficiently. In the present study we studied the cell kinetics of tumor cells by the combination of cisplatin and peplomycin using flowcytometric analysis and electron microscopy. Survival of tumor cells was lowest, when peplomycin was administrated 3 days after cisplatin. Cell kinetics showed an accumulation at the S and G2M stage in this situation, By the electron microscopic study, microvilli of tumor cells disappeared and the blebbing of tumor cells was observed, when cisplatin alone was administrated. However, when the combination of cisplatin and peplomycin was administrated to the tumor cells, tumor cells enlarged. The results suggest that the mechanism of combination therapy differed from the mechanism of cisplatin alone.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1996

Macromotion of the femoral component in artificial hip joint.

Macromotion of the femoral component was analyzed in seven loose hips associated with six patients utilizing the manual compression and distraction test. The mean vertical and varus movement of these hips were 6.4 mm and 1.2 degrees, respectively. Out of a total 120 cementless total hip arthroplasties, there was no macromotion in the control group of six patients with moderate to severe thigh pain. There was also no relationship between macromotion and the severity of thigh pain. Micromotion or rotational instability, which could not be analyzed by conventional stress radiograms, may contribute substantially to thigh pain.

Aged↗