Biomedical subjects

K Kitamura

Publications and source records attributed to K Kitamura.

At least 829 records · Page 46Linked to original sources

PubMed1990

Papillary cystic neoplasm of the pancreas: radiological and pathological characteristics in 11 cases.

Clinical charts, radiological features, macroscopic and microscopic findings, and clinical follow-up data were retrospectively reviewed in 11 patients with papillary cystic neoplasm of the pancreas (PCNP). The patients were nine women and two men, aged from 13 to 51 years with a mean age of 25 years. The greatest diameter of the PCNPs ranged from 2.5 cm to 14.0 cm with a mean size of 7.5 cm. Six tumours were located in the tail of the pancreas, two in the body and three in the head. Most patients complained of abdominal pain or a mass. Ultrasonographic and/or computed tomography findings showed five solid, four mixed (solid and cystic) and two cystic types of tumour. Angiographically, PCNP was either a hypovascular or mild hypervascular mass with a displacement of the surrounding vessels. No vascular encasement was seen. Macroscopically all 11 tumours consisted of a well defined solid mass with degenerative change of various widths, including haemorrhage, necrosis or dystrophic calcification, and were represented by three radiological types of PCNP. The 11 patients with PCNP survived for from 3 to 253 months after curative resection without any signs of local recurrence or remote metastasis. PCNP usually affects the distal portion of the pancreas of young women. Despite its huge size, PCNP should be explored with aggressive surgical intent because of the inherently good prognosis.

Adolescent↗

PubMed1990

Human monoclonal antibodies to human cytomegalovirus derived from peripheral blood lymphocytes of healthy adults.

Immunoglobulin G class human monoclonal antibodies to human cytomegalovirus (HCMV) were produced by the fusion of Epstein-Barr virus-transformed B cells and a murine myeloma cell line. The B cells were derived from the peripheral blood lymphocytes of healthy adult volunteers. Four hybridomas producing HCMV-specific monoclonal antibodies were established and each of four antibodies immunoprecipitated an HCMV-specific protein with a molecular weight of 68 kDa. However, the antibodies differed in some of their properties as characterized by indirect immunofluorescence assay and immunoblotting studies, due to the detection of different epitopes on the reacting antigen. None of the four antibodies had any virus neutralizing activity.

Adult↗

PubMed1990

Inhibitory actions of diltiazem and its derivative, TA3090 on the Ba-current recorded from smooth muscle cells of the rabbit mesenteric artery.

The effects of diltiazem and its derivative, TA3090 on the Ba-induced inward current were investigated using dispersed smooth muscle cells of the rabbit mesenteric artery. Diltiazem and TA3090 inhibited the inward current, in a concentration-dependent manner, and TA3090 was more potent than diltiazem (IC50 for diltiazem was 300 mumol/l and for TA3090, 30 mumol/l). The inward current completely recovered from the inhibitory actions of diltiazem (100 mumol/l) after its removal at holding potentials of -60 and -40 mV, though complete recovery did not occur after TA3090 (1-100 mumol/l). The voltage-dependent inactivation curves were shifted to the left by both drugs. Judging from the amplitudes of shift of V-half, the dissociation constants of inhibition for both diltiazem and TA3090 in the inactivated state were 17 mumol/l and 2.6 mumol/l, respectively. At a holding potential of -60 mV, diltiazem and TA3090 reduced the peak amplitude of the inward current, and diltiazem, but not TA3090, accelerated the decay of the current (300 ms command pulse duration). However, TA3090 did accelerate the decay of the current when a longer pulse (1 s) was applied, or when a depolarizing pulse was applied from a holding potential of -80 mV. Changes in the pH (range 6.8-7.7) of the bathing solution did not influence the decay of the current. In conclusion, TA3090 inhibits the Ca-channels of smooth muscle cells of the rabbit mesenteric artery, in a voltage-dependent manner, and its inhibitory actions are similar to those of diltiazem. However, TA3090 has much longer and stronger inhibitory actions on the Ba-inward current than diltiazem.

Animals↗

PubMed1990

Contrary effect of lactic acid on expression of neuron-specific enolase and glial fibrillary acidic protein in human glioma cells.

We examined the effect of lactic acid on cultured human glioma cell lines expressing glial fibrillary acidic protein (GFAP), vimentin and neuron-specific enolase (NSE). The growth of the cells was inhibited by the lactic acid in a dose-dependent manner. At 56 mM of lactic acid, the surviving cells of the KNS-42-c2 cell line developed slender processes and increasingly formed bizzar giant cells. In an immunofluorescence study of the lactic acid-resistant cells, the GFAP-positive cells prominently decreased in number, while the NSE-positive cells clearly increased. The vimentin was not affected throughout the experiment. After removing lactic acid from the medium, the GFAP-positive cells gradually increased in number. The method of dot immunoassay was useful for quantifying GFAP in cellular extracts. It indicated that the amount of GFAP decreased in the cells cultured with lactate-containing media and increased to the primary values after removing the lactic acid. These results may suggest that the morphological and immunochemical diversities of glioma cells are secondarily affected by cellular microenvironments such as lactic acid.

Cell Line↗

PubMed1990

Left-right asymmetry of the temporal and parietal regions in children: based on the medullary pattern of cerebral white matter.

Lateralization of the posterior temporal lobe and inferior parietal lobule in childhood was studied on CT of 276 cases and compared with those in adulthood of 371 cases. CT images were analyzed based on the morphological features of medullary branches of the cerebral white matter. In children below 5 years of age, the left planum temporale was already more posteriorly located than the right in 56%, while the right was more so in 21%. The asymmetry of the middle temporal gyrus was similar to those of the planum temporale. The folding of the inferior parietal lobule was extensive and intricate on the left side in 63% and on the right side in 8% of children, almost identical to those in the adult. The visualization rates of the intraparietal sulcus were lower compared to those of the adult, but the higher visualization of the left side was a common tendency regardless of age. These alterations in left-right asymmetry seemed to be a morphologic substratum indicating the processes of localization of auditory function to those association areas.

Adult↗

PubMed1990

Encephalo-duro-arterio-synangiosis in children with moyamoya disease.

Encephalo-duro-arterio-synangiosis (EDAS) was done in 16 Japanese children with Moyamoya disease on 22 sides. The results were evaluated clinically, angiographically, and by positron emission computed tomography (PET). Postoperative external carotid angiograms showed a good collateral circulation through EDAS in 72 percent of the treated sides. Two-thirds of the sides examined by PET showed improvement in cerebral blood circulation, particularly at the surgically-treated cortex. Postoperatively the symptoms disappeared in those with good new collateral formation. TIA, RIND, and/or involuntary movement disappeared in 31 percent and partially so in 44 percent 6 months after EDAS. The TIA in the lower limb and/or involuntary movement persisted in some children. This surgical approach seems applicable particularly for children with the ischaemic type of Moyamoya disease, however, the procedure also has drawbacks. Development of collateral circulation was insufficient in some cases, and the territories of the anterior cerebral artery (ACA) or posterior cerebral artery (PCA) were often not covered, even in those with a good new collateral formation in the middle cerebral arterial (MCA) area.

Cerebral Angiography↗

PubMed1990

Alveolar soft part sarcoma: a case report with immunohistochemical study.

We report herein, a rare case of a 28 year old Japanese man with alveolar soft part sarcoma. The patient noticed a rapidly growing mass in the inner aspect of his left thigh and a smooth-surfaced, hard nodule revealing bruit on auscultation was found on physical examination. An angiogram showed dense neovascularity from the left profunda femoris artery. Histopathologically, the tumor was composed of nests of tumor cells with hyperchromatic nuclei and vesicular cytoplasm arranged in an alveolar fashion and a histopathologic diagnosis of alveolar soft part sarcoma was made. Immunohistochemically, the tumor cells had desmin and vimentin immunoreactants in the cytoplasm, suggesting muscle origin.

Adult↗

PubMed1990

Mechanisms of endothelin-induced augmentation of the electrical and mechanical activity in rat portal vein.

Actions of porcine endothelin (ET) on the electrical and mechanical activity of the rat portal vein were investigated by means of the intracellular microelectrode and isometric tension recording techniques, ET (greater than 0.1 nM) enhanced the amplitude and frequency of the spontaneous contractions which ceased in the presence of 100 nM dihydropyridine derivatives (nifedipine or nicardipine). ET (0.15 nM) increased the frequency of the spontaneous action potentials, with no change in the basal membrane potential. Higher concentrations of ET (greater than or equal to 0.3 nM) further depolarized the membrane potential and increased the spike frequency. After blocking the spontaneous action potentials with nifedipine (100 nM), ET still depolarized the membrane. The depolarization was associated with a reduction in the electrotonic potential and was blocked in a Na-deficient solution (15.5 mM) but not in Ca-free, K-deficient or Cl-deficient solutions. In a Na-deficient solution, ET still evoked action potentials without depolarization. In Ca-free solution, ET depolarized the membrane potential with small oscillations, which were blocked by nifedipine (100 nM). The results indicate that in the rat portal vein, ET enhances electrical and mechanical responses through activation of the dihydropyridine-sensitive and voltage-dependent Ca channels. Acceleration of the Ca entry induced by ET can occur with or without depolarization of the membrane and can enhance the pacemaking mechanism.

Animals↗

PubMed1990

Cavernous hemangioma of the stomach: a case report and review of the literature.

A cavernous hemangioma of the stomach in a 41-year-old Japanese man was reported. The patient had numerous hemorrhagic telangiectasias in the skin and was also diagnosed as having a submucosal tumor of the stomach by an incidental upper gastrointestinal X-ray study. Wedge resection of the stomach was performed. The tumor was located in the submucosal, proper muscular and subserosal layers. The resected specimen showed proliferation of vascular spaces lined with a layer of endothelial cells and filled with red blood cells together with a partially calcified thrombus. The histopathologic diagnosis was cavernous hemangioma of the stomach with calcified thrombus. The patient has been doing well for twenty years. We report the case and briefly review the literature.

Adult↗

PubMed1990

Serous cystadenoma of the pancreas: radiologic and clinicopathologic features in seven cases.

Clinical charts, radiologic features, macroscopic and microscopic findings, and clinical follow-up data in seven patients with serous cystadenoma of the pancreas (SCAP) were retrospectively reviewed. The seven patients with SCAP consisted of six women and one man, and their ages ranged from 52 to 76 years with a mean age of 64.9. The most common symptoms were abdominal mass or pain. The greatest diameter of the seven tumors ranged from 2cm to 10cm with a mean diameter of 6.6cm. On ultrasonograms and/or computed tomograms, the tumors were visualized as lobulated masses containing numerous small cysts. Three tumors angiographically examined were all characteristic hypervascular masses with neovascularity. Macroscopically, the tumors were well-defined lobulated masses containing many cysts with a central scar. Microscopically the cysts were lined with a layer of cuboidal epithelium with centrally placed round nuclei and clear cytoplasms containing abundant glycogen. One patient had undergone a cystojejunostomy five years before the complete resection and the tumor increased in size necessitating a pancreatoduodenectomy. The seven patients with SCAP were doing well without any signs of local recurrence or distant metastasis during the period from 2 months to 120 months after a complete resection. Despite its enormous size at the time of diagnosis, SCAP should be resected with aggressive intent because the complete resection produces a favorable clinical course.

Aged↗

PubMed1990

Some electrical properties of human pregnant myometrium.

Membrane properties of the human pregnant myometrium were investigated with the conventional microelectrode and patch clamp methods. The majority of preparations produced spontaneous action potentials at a very low frequency, and action potentials were inhibited in sodium-deficient or calcium-free solutions. With the patch clamp technique with 120 mmol/L cesium-20 mmol/L tetraethylammonium in the pipette, the inward current was evoked by a depolarizing pulse above -40 mV from a holding potential of -60 mV and maximum amplitude was obtained at 0 mV. At a holding potential of -100 mV, the inward current could be evoked with less positive depolarizing pulses, and the membrane potential that evoked the maximum amplitude of inward current was shifted to a more negative potential. Single-channel current recording revealed that two types of calcium channels existed in human pregnant myometrium, with single-channel conductances of 12 and 29 pS. One of the calcium channels (12 pS) was inactivated at a holding potential of -60 mV.

Action Potentials↗

PubMed1990

Phenytoin-induced gingival overgrowth in rats infected with Streptococcus sobrinus 6715.

Inbred Fischer rats were fed a high sucrose diet (No. 2000) containing phenytoin (5,5-diphenyl-hydantoin) for 52 days, which produced serum and salivary PHT levels of 13-14 and 2.6-2.7 micrograms/ml, respectively. Gingival overgrowth was induced in the molar region of all PHT-treated rats but was more severe in Streptococcus sobrinus 6715-infected rats than in non-infected rats, which had lower plaque scores. No significant overgrowth was found in rats infected with Strep. sobrinus and fed the same diet without PHT. Thus dental plaque accumulation enhanced, but was not essential for the development of the PHT-induced gingival overgrowth. Histological examination showed that the density of fibroblasts and connective tissue fibres was similar in all groups. This experimental model could serve as a useful means of understanding the pathogenesis of PHT-induced gingival overgrowth.

Animals↗

PubMed1990

Gingival overgrowth induced by cyclosporin A in rats.

Gingival overgrowth, which is one of the major side-effects of this immunosuppressive agent, was studied in specific pathogen-free Fischer rats fed diet No. 2000 containing 56% sucrose. Marked macroscopic overgrowth was noted in mandibular gingiva of all the rats fed this diet containing cyclosporin A. The overgrowth was more severe in buccal than in lingual gingiva. Rats fed the cyclosporin-containing diet and infected with Streptococcus sobrinus 6715 had the most gingival overgrowth. Histopathological examination revealed that the bulk of the enlargement consisted of fibrous connective tissue without a marked increase in the number of fibroblasts or inflammatory cells.

Animals↗

PubMed1990

Chromatographic characterization of immunoreactive endothelin in rat lung.

Using a specific and sensitive radioimmunoassay for endothelin, combined with gel filtration and reverse phase high performance liquid chromatography, the molecular form of immunoreactive endothelin in the rat lung was investigated. On reverse phase high performance chromatography, the major immunoreactive endothelin in the rat lung emerged at a position identical to that of authentic endothelin-1. After oxidation of the immunoreactive endothelin by H2O2, the immunoreactivity migrated to a position identical to that of Met-sulfoxide endothelin-1. These data indicate that the major immunoreactive endothelin in the rat lung is not endothelin-3 (putative rat/human endothelin), but is identical or very similar to endothelin-1 (porcine/human endothelin).

Amino Acid Sequence↗

PubMed1990

Two pediatric cases with occlusions of the ipsilateral internal carotid and posterior cerebral arteries associated with moyamoya vessels: "unilateral" moyamoya disease.

Two pediatric cases of unilateral Moyamoya disease are reported. The clinical symptoms and the findings of electroencephalography, angiography, and positron emission tomography in these cases were quite the same as those in the cases with bilateral involvement, which is typical of this disease. In both cases angiography demonstrated unilateral occlusion not only of the internal carotid artery but also of the posterior cerebral artery together with so-called Moyamoya vessels on the same side. Although infectious diseases were mentioned in the patients' histories, no obvious basic diseases related to the cerebrovascular occlusion were detected. We consider that these cases with unilateral involvement suggest the presence of unilateral Moyamoya disease without progression onto the opposite side.

Animals↗

PubMed1990

Benign recurrent vertigo in Japanese.

Twenty-one cases of Japanese patients exhibiting recurrent attacks of vertigo are reported. Fifteen of the cases are females. The mean age of onset of the vertigo is 30.8 years. In 11 patients, the duration of attacks is less than 10 min. Caloric responses are normal in all patients. Although two patients demonstrate hearing loss, the rest of the patients exhibit no hearing loss. Headaches have been reported in all patients. Eighteen of the patients experience headaches associated with the vertiginous attacks. The clinical features observed in our cases are consistent with a diagnosis of benign recurrent vertigo. Four patients exhibit cranial nerve symptoms which are features of basilar artery migraine. Basilar artery migraine is attributed to a migrainous disturbance of the basilar artery. Benign recurrent vertigo is also ascribed to a migrainous disorder affecting the vestibular system, thus it is a localized clinical manifestation of basilar artery migraine.

Adolescent↗

PubMed1990

Monoclonal antibody A7 tumor localization enhancement by its F(ab')2 fragments to colon carcinoma xenografts in nude mice.

The monoclonal antibody A7 (MoAb A7), which belongs to IgG1, was digested with pepsin to yield F(ab')2 fragments. The maximum binding to the human colon cancer cell line, SW1116, was 27% with 125-I labeled whole MoAb A7 and 24% with 125-I labeled F(ab')2 fragments using an in vitro binding assay. The results showed that the binding activity of F(ab')2 to SW1116 was practically the same as that of whole MoAb A7. The preferred localization of the fragments to tumor tissue, compared with normal mouse tissue, was demonstrated in mice carrying SW1116 xenografts. The tumor:blood ratio three days after injection was 2.64:18.5 for whole MoAb A7:F(ab')2, respectively. The tissue:blood ratios for the F(ab')2 fragments showed a value of 18.5 in tumors, whereas its was a value less than 1.0 in normal organs. The tumor accumulation of F(ab')2 fragments was also dependent on the antigenic expression of each tumor among xenografts of colon carcinoma SW1116 and WiDr, and squamous cell carcinoma KB. In kinetic experiments with whole MoAb A7 and its F(ab')2 fragments, whole MoAb A7 was lost, with a half-life of 4 days, in both blood and tumors, whereas F(ab')2 fragments were rapidly lost with a half-life of 1.5 days. These results suggested that the F(ab')2 fragments were cleared from the blood faster than was whole MoAb A7.

Animals↗

PubMed1990

Pirarubicin, a novel derivative of doxorubicin. THP-COP therapy for non-Hodgkin's lymphoma in the elderly.

Pirarubicin (tetrahydropyranyl adriamycin, THP) is a derivative of doxorubicin. Forty-three non-Hodgkin's lymphoma (NHL) patients 65 years of age or older were treated with a combination therapy including cyclophosphamide (CPA), vincristine (VCR), prednisone (PSL), and THP (THP-COP). The THP-COP regimen consisted of THP, 30 mg/m2 i.v. on day 1; CPA, 500 mg/m2 i.v. on day 1; VCR, 1.0 mg/m2 i.v. on day 1; and PSL, 60 mg orally for 5 consecutive days. The sequence was repeated at 21- to 28-day intervals for a minimum of four cycles. Of the 43 patients, 13 (30.2%) achieved a complete response (CR) and 21 (48.8%) a partial response (PR). Nine patients (21.0%) had primary treatment failure, which included a minimal response, no change, and progressive disease. Thus, the response rate (CR or PR) was 79.1%. Twenty-six of 29 previously untreated patients (89.7%) achieved a CR or PR, whereas only 8 of 14 previously treated patients (57.1%) did (p less than 0.05). Because THP is a derivative of doxorubicin, the results for the eight patients previously treated with doxorubicin are noteworthy; four achieved a CR or PR. No patients had any cardiac toxicity, including congestive heart failure, attributable to THP. Furthermore, four patients who showed a decreased ejection fraction before treatment completed the full course of THP-COP chemotherapy without any progression of the cardiac complication. THP is considered to be active against NHL in the elderly and comparable to doxorubicin in combination chemotherapy.

Aged↗