Biomedical subjects

H Kuwabara

Publications and source records attributed to H Kuwabara.

At least 91 records · Page 5Linked to original sources

PubMed1992

Recombinant human granulocyte colony-stimulating factor enhanced cytotoxicity of Ara-C in Ara-C-resistant leukemic cells from a patient with biphenotypic leukemia in cell kinetic quiescence.

In vitro preincubation with recombinant granulocyte colony-stimulating factor(rhG-CSF, 100 ng/ml) enhanced the cytotoxicity of 1-beta-D-arabinofuranosylcytosine(Ara-C) in leukemic cells resistant to Ara-C from a patient with biphenotypic leukemia. Treatment of the cells with rhG-CSF resulted in a 17-fold increase in DNA synthesis, 4.6-fold increase in percentage of S-phase, and a two-fold increase in Ara-CTP formation. Maximal effect was observed at 72 h of incubation. Combination chemotherapy with rhG-CSF and Ara-C to the patient showed remarkable cytoreduction. These results indicate that recruitment of resistant leukemic cells in cell kinetic quiescence is inducible by rhG-CSF and that it is possible enhancement of the cytotoxicity to cell cycle-specific drugs such as Ara-C.

Cell Cycle↗

PubMed1992

Density of perfused capillaries in living human brain during functional activation.

Recent evidence has indicated that functional activation of cerebral cortex is accompanied by increases of blood flow and glucose consumption but not oxygen consumption. No explanation has been advanced for this change of the flow-metabolism couple. We formulated the hypothesis that oxygen delivery to brain tissue is diffusion-limited by the enormous hemoglobin binding, and rate-limiting for the oxygen consumption of the tissue. One prediction of this hypothesis is very low oxygen tensions in the tissue. A second prediction is the inability of oxygen consumption to increase during functional activation in the absence of recruitment of capillaries for the oxygen diffusion capacity. We designed a study to test the latter prediction by calculating the density of functioning capillaries during vibrotactile stimulation of the parietal cortex. We defined functioning capillaries as capillaries that transport glucose and therefore calculated the capillary density from the glucose diffusion capacity (K1) of the cerebral capillaries. We confirmed the presence of a partial flow-CMRglc couple (2:1) during the functional activation. Oxygen consumption did not change despite an increase of capillary density in proportion to the change of blood flow.

Brain↗

PubMed1992

Pigmented villonodular synovitis (giant cell tumor of the synovium) occurring in the vertebral column. Report of a case.

A case of pigmented villonodular synovitis (giant cell tumor of the synovium) involving the vertebral column is presented. The tumor grew outside the dura and extended to the paravertebral connective tissue, causing sensory and motor disturbance indicative of spinal cord compression. This anatomic location is very rare for lesions of this type, and to our knowledge, this case is only the fifth reported in the English-language literature.

Adult↗

PubMed1992

[The effect of etoposide on influx and efflux of cytosine arabinoside in P388 murine leukemic cells].

We studied the effects of etoposide on the influx, intracellular accumulation and efflux of ara-C in P388 leukemic cells. Etoposide inhibited the active influx of ara-C in a dose dependent manner, and the inhibition was reversible. Etoposide also affected the intracellular accumulation of ara-C, though its inhibitory effect for the intracellular accumulation was weaker than that for the influx of ara-C. It was also shown that etoposide inhibited the active efflux of ara-C. Furthermore, etoposide inhibited the active transport of ara-C bidirectionally but the insensitive route of etoposide existed especially at high concentration of ara-C. The effect of inhibition of the transport of ara-C on the accumulation of ara-C was more significant at lower concentration of ara-C. Judging from the drug concentrations used in this study, an interaction between etoposide and ara-C could occur in the clinical treatment.

Animals↗

PubMed1992

Multicentric reticulohistiocytosis. Report of a case with electron microscopic studies.

Electron microscopic examination of multicentric reticulohistiocytosis (MR) cells is reported. Most of the cells contained numerous dense bodies which seemed to be lysosomes. Complex interdigitations of the membranes of the adjacent MR cells were distinctive findings. Some of the cells contained myelinated dense bodies in the cytoplasm. Histochemically, the cells were strongly positive for acid phosphatase, alpha-naphthyl butyrate esterase and lysozyme. From these observations, the majority of MR cells appeared to be proliferations of monocyte/macrophage-derived cells. In the synovium, these cells resembled type A synovial cells. Other smaller and fewer cells had many rough endoplasmic reticulum (RER), and these resembled type B synovial cells. In the synovium, MR cells might be formed by proliferation and fusion of synovial cells.

Adult↗

PubMed1992

A light and electron microscopic histochemical study on lectin binding to cells with high metastatic potential in Lewis lung carcinoma.

Lectin binding to tumor cells in tissue sections of nonmetastatic and metastatic murine Lewis lung carcinoma (LLC) was assessed by light and electron microscopy using a lectin-gold technique. Ulex europaeus agglutinin-I (UEA-I) and peanut agglutinin (PNA) showed no binding, whereas concanavalin A (Con A), soybean agglutinin (SBA), Dolichos biflorus agglutinin (DBA), Maclura pomifera agglutinin (MPA), and Ricinus communis agglutinin-I (RCA-I) bound equally to the transplanted sites and metastases. However, wheat germ agglutinin (WGA) bound to metastases more highly than to the transplanted sites and there was a statistically significant difference (P less than 0.01) between the transplanted sites and metastases with regard to pre-embedding method. The tumor cells binding to WGA clearly decreased in number after sialic acid pretreatment and were rich in more well-differentiated organelle. In the bromodeoxyuridine (BrdUrd) labeling in vivo, cell proliferation was greater in the metastatic sites than in the transplanted sites. The above findings suggest that glycoconjugates on the tumor cell surface are altered in the process of metastasis and correlate with metastatic potential and cell proliferation.

Animals↗

PubMed1991

Dopa decarboxylase activity of the living human brain.

Monoaminergic neurons use dopa decarboxylase (DDC; aromatic-L-amino-acid carboxy-lyase, EC 4.1.1.28) to form dopamine from L-3,4-dihydroxyphenylalanine (L-dopa). We measured regional dopa decarboxylase activity in brains of six healthy volunteers with 6-[18F]fluoro-L-dopa and positron emission tomography. We calculated the enzyme activity, relative to its Km, with a kinetic model that yielded the relative rate of conversion of 6-[18F]fluoro-L-dopa to [18F]fluorodopamine. Regional values of relative dopa decarboxylase activity ranged from nil in occipital cortex to 1.9 h-1 in caudate nucleus and putamen, in agreement with values obtained in vitro.

Brain↗

PubMed1991

Decreased DNA polymerase sensitivity to 1-beta-D-arabinofuranosylcytosine 5'-triphosphate in P388 murine leukemic cells resistant to vincristine.

P388 murine leukemic cells 28.6-fold resistant to vincristine were cross-resistant to doxorubicin and etoposide. Although the intracellular ara-CTP in P388 murine leukemic cells resistant to vincristine (P388/VCR) was significantly higher than that in the parent cells, the cytotoxic effect of ara-C was not significantly different between the parent and resistant cells. Therefore, we investigated the DNA synthesis in P388/VCR and its parent cell line using the permeable cell system. The DNA synthesis in P388/VCR cells was less sensitive to ara-CTP and dTTP than that in P388 parent cells. These results suggested that the characteristics of DNA polymerase in P388/VCR cells might change when the cells developed multiple drug resistance.

Animals↗

PubMed1991

Membrane transport of 1-beta-D-arabinofuranosylcytosine and accumulation of 1-beta-D-arabinofuranosylcytosine 5'-triphosphate in P388 murine leukemic cells resistant to vincristine.

The membrane transport of ara-C and intracellular ara-CTP accumulation were investigated in P388 murine leukemic cells resistant to vincristine (P388/VCR) and its parent cell line. The transport of ara-C in P388/VCR cell line was a 1.4-fold increase at 30 sec compared to that in P388 parent cell line (P less than 0.01). The increase of the transport of ara-C in P388/VCR cell line, however, was not completely abolished by the nucleoside transport inhibitor, nitrobenzylthioinosine (NBTI) to the level in parent cell line. Scatchard analyses revealed that the resistant cells had significantly less NBTI binding sites than the parent cells had. These results suggested that the changes in ara-C transport in P388/VCR cells were due, in part, to increase of NBTI-insensitive transport sites in the membrane. The measurement of the intracellular ara-CTP concentration by high-performance liquid chromatography revealed that the intracellular ara-CTP level in P388/VCR cells was also significantly higher than that in parent cells (1.4-fold, P less than 0.01). As the transport of ara-C is rate limiting at a concentration of 1 microM in the both cell lines, we concluded that the accumulation of ara-CTP in P388/VCR cells might have partially resulted from the enhancement of the ara-C transport.

Animals↗

PubMed1991

Malignant mesothelioma of the tunica vaginalis testis. Report of a case and review of the literature.

An autopsy case of malignant mesothelioma of the tunica vaginalis testis in a 60-year-old man is described. The tumor showed widespread metastasis via the lymphatics, leading to the patient's death five years after diagnosis. A review of 38 previously described cases is also presented. The most frequent presenting symptom was hydrocele. When a hydrocele in association with a paratesticular tumor is present, aspiration cytology should be performed first. In most of the cases with a fatal outcome, the tumors metastasized to the retroperitoneal lymph nodes. Once the diagnosis has been made, lymphangiography or CT scan should be done immediately.

Adult↗

PubMed1991

Dendritic cells in the murine dermis in delayed-type contact hypersensitivity. An ultrastructural and immunocytochemical study.

Dendritic cells within the dermis in the later stages of delayed-type contact hypersensitivity were examined ultrastructurally and immunohistochemically. The immunohistochemical observations were done using monoclonal antibody M1-8, which reacts specifically with murine Langerhans cells and interdigitating cells. Seventeen hours after challenge, infiltrating cells in the dermis included dendritic cells, possibly so-called indeterminate cells, monocytoid cells and Langerhans cells. Immunohistochemically, the indeterminate cells and some monocytoid cells were M1-8-positive. These findings suggest that indeterminate cells are intimately related to Langerhans cells, and that they belong to the mononuclear phagocyte system. M1-8 is a very useful marker for studies on the kinetics of Langerhans cells or indeterminate cells.

Animals↗

PubMed1991

A light and electron microscopical study of membranocystic lesions in a case of lupus erythematosus profundus.

A light and electron microscopical study on membranocystic lesions (MCL) in a case of lupus erythematosus profundus (LEP) is reported. The patient was a 16-year-old female who presented with subcutaneous nodules on both upper arms. The light microscopic features were consistent with LEP, and the result of an immunofluorescence band test supported this diagnosis. A peculiar finding in this case was MCL in the subcutaneous tissue. Ultrastructurally, these were thin membranes without a tubular structure and tortuous thick membranes composed of minute tubules. The lesions were very similar to the fatty tissue changes in membranous lipodystrophy. On the other hand, the basement membranes of the blood vessels were thickened and multilayered, and the lumina were narrowed by endothelial swelling and thickening of the vessel wall. Our findings suggest that the MCL in LEP result from circulatory disturbance of the fat tissue.

Adolescent↗

PubMed1991

[Enzyme-linked immunosorbent assay using monoclonal antibodies for direct serotyping of enteric adenoviruses in feces].

We were prepared three monoclonal antibodies in which the monoclone 12D was type specific for Adenovirus 40 (Ad40), 1F was type specific for Ad41 and 15D was group specific for Ads. For identification of enteric adenoviruses (EAd) in stool specimens, enzyme-linked immunosorbent assay (ELISA) test using monoclonal antibodies was developed. Results of identification by the ELISA tests using monoclonal antibodies to EAd on 15 fecal samples in which Ad particles were found by electron microscopy showed complete coincidence to those of Sma 1 restriction endonuclease cleavage. From these results, the ELISA tests employing EAds type specific monoclonal antibodies proved to be specific and this was a rapid technique for laboratory diagnosis of EAd in fecal specimens of viral gastroenteritis. Fifty-eight fecal samples with Ad particles positive by EM were serotyped by the ELISA using monoclonal antibodies. Eleven fecal samples were identified as Ad40, 25 as Ad41, 1 as double infection with Ad40 and Ad41, and 4 as non-EAd. These results indicated that Ad41 was more dominant than Ad40 during April, 1986 to January, 1989 in Matsuyama city.

Adenoviruses, Human↗

PubMed1991

Statistical analysis of bilingual speaker's speech for cross-language voice conversion.

The goal of cross-language voice conversion is to preserve the speech characteristics of one speaker when that speaker's speech is translated and used to synthesize speech in another language. In this paper, two preliminary studies, i.e., a statistical analysis of spectrum differences in different languages and the first attempt at a cross-language voice conversion, are reported. Speech uttered by a bilingual speaker is analyzed to examine spectrum difference between English and Japanese. Experimental results are (1) the codebook size for mixed speech from English and Japanese should be almost twice the codebook size of either English or Japanese; (2) although many code vectors occurred in both English and Japanese, some have a tendency to predominate in one language or the other; (3) code vectors that predominantly occurred in English are contained in the phonemes /r/, /ae/, /f/, /s/, and code vectors that predominantly occurred in Japanese are contained in /i/, /u/, /N/; and (4) judged from listening tests, listeners cannot reliably indicate the distinction between English speech decoded by a Japanese codebook and English speech decoded by an English codebook. A voice conversion algorithm based on codebook mapping was applied to cross-language voice conversion, and its performance was somewhat less effective than for voice conversion in the same language.

Algorithms↗

PubMed1991

Intracellular dCTP/ara-CTP ratio and the cytotoxic effect of ara-C.

In this study, the relationship between the dCTP/ara-CTP ratio and the cytotoxic effect of cytosine arabinoside (ara-C) was investigated. Intracellular levels of dNTPs and ara-CTP were analyzed by high-performance liquid chromatography. Although doubling time and intracellular dCTP levels were different in each of the cells, there was a consistent relation between the intracellular dCTP/ara-CTP ratio and the cytotoxic concentration of ara-C. These data suggest that the intracellular dCTP/ara-CTP ratio is one of the important factors for considering the cytotoxic action of ara-C.

Arabinofuranosylcytosine Triphosphate↗

PubMed1991

[A manual for community mental health activities for a public health center in Japan].

A system for treatment of persons with chronic mental disease such as schizophrenics in the present structure of the Japanese public Health Center is proposed. Presently, while cases are handled by responsible staff members, incorporation into the health center system with full utilization of its personnel and resources is seldom accomplished. There is a necessity for a systems approach in order to organize essential programs that would provide care for the mentally diseased. Health centers would have three main roles in this system: as a coordinator of mental health resources in the community, as a specialized agency for case management, and responsibility for public relations in its service area. For proper administration of its system, health centers should follow a team concept. The team would consist of a director of health centers, physicians, part-time psychiatrists, public health nurses, psychiatric social workers and clerical staff. At case conferences discussion of whether a prospective case should be registered, assessment of the needs, and development of management plans for all of the registered cases would be conducted. The files and documents of each case would be deleted or re-registered 5 years after initial registration. Cases would have a case-manager to coordinate public health care, including home visits, family care, psycho-educational consultation and crisis intervention. Health centers would be responsible for bringing together available social resources such as sheltered workshops and transient residential programs. The goal of health centers' mental health activities would be to facilitate the normalization of the mentally diseased within the community.

Community Health Centers↗

PubMed1991

Thoracic duct cyst of the neck: a case report.

A thoracic duct cyst was excised from the left side of the neck of a 63-year-old woman. It was 6.5cm in length and 3.5cm in width, and was located behind the common carotid artery and jugular vein. The proximal portion of the thoracic duct with a narrowed lumen was in direct contact with the lateral surface of the cyst and the venous angle. The lower end of the cyst extended into the mediastinum to immediately above the aortic arch; the inferior portion of the thoracic duct descended from the bottom of the cyst into the mediastinum behind the aorta. The cyst was unilocular with a fluid content high in triglyceride (3350mg/dl). Its wall was muscular and permeated with lymphatic vessels.

Cysts↗

PubMed1991

[Primary pulmonary artery sarcoma showing multiple HDA on the brain CT--an autopsy case report].

A 67-year-old female suddenly developed a speech disturbance and right hemiplegia. She was diagnosed as having cerebral infarction. Then 2 months later, she had a fever and disturbance of consciousness. She died of respiratory insufficiency. The brain CT showed multiple high density areas with niveau. The autopsy revealed primary pulmonary artery sarcoma and multiple metastasis to the brain, the small intestine, etc. Primary pulmonary artery sarcoma is a very rare tumor which can occur in the pulmonary trunk of a person from any age groups. This case is a very rare one with cerebral metastasis.

Aged↗