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Biomedical subjects

S Hirata

Publications and source records attributed to S Hirata.

At least 19 recordsLinked to original sources
PubMed2008

Neuroblastoma presenting with dilated cardiomyopathy.

We report an infant with neuroblastoma who presented with dilated cardiomyopathy. A 3-month-old girl presented with dilated cardiomyopathy diagnosed as stage III neuroblastoma. Since total resection was impossible, chemotherapy was started. Cardiomyopathy was normalized by improvement of neuroblastoma. The prompt improvement of cardiac function following treatment of neuroblastoma suggested that cardiomyopathy in this patient was caused by the increase in catecholamines secreted by neuroblastoma and that reduction in catecholamines by treatment of neuroblastoma led to improvement in the cardiomyopathy.

Cardiomyopathy, Dilated↗
PubMed2006

Neuronal activities in the reward phase in primary and higher-order gustatory cortices of monkeys.

We examined neuronal activities in the reward phase of a taste discrimination GO/NOGO task and the reversal from the primary (PGC; areas G, 3 and 1-2) and higher order gustatory cortices (HGC, PrCO and OFC) in the monkey. Sucrose was given as reward for both GO (lever pressing during LED) and NOGO responses when correct. Three ON responses, synchronous with sucrose onset at correct or LED offset at incorrect trials were found: C- and I- types increased discharges only at correct or incorrect trials, while C-I type changed discharges at both. Of the latter two classes were noted; Class I increased discharges at correct and decreased them at incorrect trials, and Class II increased discharges at both. C-type and Class I were most numerous in both PGC and HGC except for the OFC in which Class II responses predominated. I-type was rare. Onset latencies at correct and incorrect trials were significantly correlated in the HGC but not in the PGC. It was suggested that C-type responses represented the gustatory nature of reward, I-type neurons error signals, and that Class I of C-I type indicated the arrival or omission of the reward, and Class II anticipation of reward delivery.

Action Potentials↗
PubMed2006

Case study of a pregnant woman with decidualized ovarian endometriosis whose preoperative findings suggested malignant transformation.

BACKGROUND: Because both decidualization and malignant transformation of endometriosis are characterized by mural nodules on the wall of the cyst, the preoperative differential diagnosis is reportedly difficult. CASE: A 31-year-old woman was referred to our hospital at ten weeks of gestation. Sonographic examination revealed an intrauterine gestational sac and ovarian endometrial cyst. At 21 weeks of gestation, characteristic findings associated with malignant transformation of ovarian endometriosis were seen on color-flow Doppler sonography and contrast magnetic resonance imaging. Under the diagnosis of malignant transformation of ovarian endometriosis, right salpingo-oophorectomy was performed at 22 weeks' gestation. However, histopathologic examination revealed ovarian endometriosis with marked decidual changes but no evidence of malignancy. CONCLUSION: During pregnancy, intracystic vascularized excrescences of an endometrial cyst indicate not only malignant transformation but also decidualization. Thus, the preoperative differential diagnosis is reportedly difficult. However, the present findings of decidualization on magnetic resonance imaging seemed to be slightly different from those of malignant transformation, and therefore, might help distinguish decidualized endometriosis from malignant transformation preoperatively.

Adult↗
PubMed2005

X-Ray photoemission study of CuIr2S4: Ir3+-Ir4+ charge ordering and the effect of light illumination.

We have studied the electronic structure of the spinel-type compound CuIr2S4 using x-ray photoemission spectroscopy (XPS). CuIr2S4 undergoes a metal-insulator transition (MIT) at approximately 226 K. In going from the metallic to insulating states, the valence-band photoemission spectrum shows a gap opening at the Fermi level and a rigid-band shift of approximately 0.15 eV. In addition, the Ir 4f core-level spectrum is dramatically changed by the MIT. The Ir 4f line shape of the insulating state can be decomposed into two contributions, consistent with the charge disproportionation of Ir3+:Ir4+=1:1. XPS measurements under laser irradiation indicate that the charge disproportionation of CuIr2S4 is very robust against photo-excitation in contrast to Cs2Au2Br6 which shows photo-induced valence transition.

Journal Article↗
PubMed2005

Rapid disease progression correlates with instability of mutant SOD1 in familial ALS.

Studies on the clinical course of familial ALS suggest that the duration of illness is relatively consistent for each mutation but variable among the different mutations. The authors analyzed the relative amount of mutant compared with normal SOD1 protein in the erythrocytes from 29 patients with ALS with 22 different mutations. Turnover of mutant SOD1 correlated with a shorter disease survival time.

Adult↗
PubMed2005

Interactions between clarithromycin and digoxin in patients with end-stage renal disease.

OBJECTIVE: To report a significant increase in the serum levels of digoxin associated with the use of clarithromycin in six patients undergoing renal replacement therapy. CASE SUMMARY: All six patients were males with end-stage renal disease and in need of renal replacement therapy. Four patients were anuric. The mean age was 78.8 +/- 5.8 (66-83) years. All patients except one, who was treated by hemofiltration, were treated by hemodialysis. All patients except one, who had been treated with metildigoxin (0.35 mg/week), were also taking digoxin (0.375 mg/week). Clarithromycin was administered at a dose of 200-400 mg/day for the treatment of bronchitis in all patients. The concomitant administration of clarithromycin increased serum digoxin levels from 1.8-4.0-fold in all cases. In two of six cases, a high probability of digoxin intoxication and suspicion of digoxin intoxication was evident. In three of six cases, serum digoxin levels increased within 12 days after the co-administration of clarithromycin, while in the other three cases, serum digoxin levels were increased 53-190 days after the administration of clarithromycin. CONCLUSION: The simultaneous administration of clarithromycin caused an increase in digoxin levels in six patients undergoing renal replacement therapy. The increase in the serum digoxin can be attributed to the inhibition of P-glycoprotein in the intestine and/or bile capillary rather than the kidney by clarithromycin since renal function was dramatically impaired, and four of the patients were anuric. The issue of why serum digoxin levels were increased so late in three patients undergoing renal replacement is unclear. However, this interaction seemed to be clinically significant even in ESRD patients, whose renal function was highly impaired. The simultaneous use of digoxin and clarithromycin should be avoided even in patients undergoing renal replacement therapy whose renal function is impaired, since digoxin levels may increase unexpectedly.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2004

Photoemission study of YBa(2)Cu(3)O(y) thin films under light illumination.

Heterojunctions of Nb-doped SrTiO3 substrate and YBa(2)Cu(3)O(y) thin films show photoconductivity and photovoltaic effects due to photocarrier injection. Photocarrier injection is expected to be a new carrier doping method in strongly correlated systems instead of chemical substitution. We have studied the nature of photocarrier injection in YBa(2)Cu(3)O(y)/SrTiO(3):Nb using x-ray photoemission spectroscopy with pulsed laser excitation. The core-level spectra shift to higher binding energy by 0.78 eV under pulsed laser illumination at 30 Hz. The energy shift corresponds to the photovoltage, which arises at the interface. In addition, we have observed that the energy shift strongly depends on the frequency of the laser. The lifetime of the injected photoholes has been estimated to be 40 ms by analyzing the frequency dependence.

Journal Article↗
PubMed2004

Floating-Harbor syndrome: case report and craniofacial phenotype characterization.

Floating-Harbor syndrome is a rare genetic disorder of unknown aetiology. It was described for the first time in 1973. The syndrome is characterized mainly by short stature, delay in speech development and characteristic facial features. This article describes a report of a case of the syndrome and emphasizes the oral aspects, including descriptions of soft tissues, teeth, occlusion, stage of dental development and findings on examination of the temporomandibular joint. The treatment provided and its outcome is also described. Hopefully this information will be compared with findings from other patients in the future to assist in clarifying the phenotype of the Floating-Harbor syndrome.

Child↗
PubMed2003

Fundamental physio-mitotic theory.

In differentiation division, the mitosis occurring within all tissues consists of more than one type of mitosis. It occurs as two antagonistic types: the essential duplication mitosis activated by the effect of duplication factor and the antagonistic maturation mitosis which develops from the essential type and is further stimulated by maturation factor. These different types of mitosis play antagonistic roles in histological development, while maintaining a specified physio-mitotic balance through their respective mitotic factors and mitotic regulatory mechanisms in the tissues. Depending on the physio-mitotic balance between duplication and maturation mitosis, each layer of organized tissue, comprised of intrinsic functional cells, differentiates from one of the three germ layers, without errors that create abnormal characteristics. In this way, the tissues establish histological identity and continuity while maintaining a prescribed histological organization without excess or reduced multiplication within the tissues. This forms the fundamental basis of the physio-mitotic theory.

Animals↗
PubMed2003

Placental site trophoblastic tumor: p53 gene analysis.

BACKGROUND: Placental site trophoblastic tumor (PSTT) is the rarest type of trophoblastic neoplasm. Because of its rarity, the clinical behavior and pathogenesis of PSTT are still unclear. CASE: A 20-year-old woman presented with secondary amenorrhea and irregular vaginal bleeding. Examination of the patient revealed elevated serum hCG and a uterine mass. The specimen obtained by curettage was diagnosed as possible PSTT. The patient was treated with two cycles of EMA/CO, but her uterine mass increased in size. Subsequently, she underwent total abdominal hysterectomy. Microscopic observation revealed a PSTT. To estimate the status of expression of p53 protein and to determine whether p53 gene mutation was present in this PSTT, we carried out immunohistochemical staining for p53 and PCR-SSCP analysis. Immunohistochemical staining for p53 revealed intense nuclear labeling, but no p53 gene mutation was detected in exons 5-8. CONCLUSION: Analysis of the p53 gene may aid understanding of the pathogenesis of PSTT.

Adult↗
PubMed2003

[Acute pulmonary embolism performed embolectomy under percutaneous cardiopulmonary support successfully after lung cancer operation].

We have experienced a case of acute pulmonary embolism after lung cancer operation. The case was a 74-year-old male. He underwent left upper lobectomy due to squamous cell carcinoma. He fell into shock state suddenly on the 6th day postoperatively. We diagnosted acute pulmonary embolism, performed urgent embolectomy under percutaneous cardiopulmonary support (PCPS). Postoperative course was smooth, and he has returned to normal daily life. Urgent diagnosis and management are indispensable for acute pulmonary embolism after lung cancer operation from the aspect of residual among of pulmonary vascular bed.

Acute Disease↗
PubMed2002

Mesoderm layer and fibrous support tissues essential for embryological differentiation.

Of the three germ layers, the mesoderm layer is the first to differentiate from the blastula and continues to lead the embryological differentiation while initiating the secretion of antagonistic duplication and maturation factors. After differentiation and while maintaining the secretion of duplication and maturation factors, the fibrous tissues that differentiated from mesoderm play an essential role in regulating the physio-mitotic conditions of functional tissues found in all histological organizations. Accordingly, some defects in mitotic interaction between the fibrous and functional tissues organized into structural units may give rise to various diseases such as carcinoma, sarcoma, leukemia, and fibro-multiplastic, myo-atrophic and neuroatrophic diseases. This defect in mitosis suggests the most important step in achieving eradication of these diseases.

Blastula↗
PubMed2002

Cancerous genetic peculiarities non-responsible for cancer development.

Certain genetic peculiarities recently identified in cancer cells have generally been regarded as the abnormalities responsible for cancer development. However, these abnormalities may also be found in maturable cancer cells and are not limited only to the non-maturable type. As previously described by the authors, cancer tissue consists of two types of cancerous cells: maturable and non-maturable. The development of cancer may be dependent only on the non-maturable cancerous stem cells, not on the maturable type. Since the non-maturable cell may be solely responsible for carcinogenesis, the relevant genetic peculiarities that are also found in the maturable cancer cells should not be regarded as the abnormalities responsible for carcinogenesis.

Cell Division↗
PubMed2002

Physio-mitotic theory and a new concept of cancer development.

In the physio-mitotic theory, general mitosis consists of two different types: maturation and duplication. While being co-regulated by mechanisms involving maturation and duplication factors, these two types of mitotic activities each play a respective role in the antagonistic histological development of the other. According to the theory of systematic organization, each type of organic tissue is always developed and established under certain physiological conditions. As an organoid tissue, cancerous tissue must also fundamentally develop according to that theory. Consequently, a new concept of cancer development should be devised based on the physio-mitotic theory.

Animals↗
PubMed2002

Physio-mitotic theory and a new concept of leukemia development.

In the physio-mitotic theory described previously by the authors (10), general mitosis consists of two different types: essential duplication and converted maturation. These two types of mitosis are regulated by mechanisms involving maturation and duplication factors, and each plays a role in the antagonistic histological development of the other.According to this theory, every kind of leukocyte is produced through mitosis in the bone marrow and migrates during cell turnover to the bloodstream. However, in leukemia a highly excessive number of leukocytes and leuko-blastocysts appear in the bloodstream. This excessive amount is greater than the physiological capability of cells in the bone marrow alone. Such an extremely large group of cells would not be produced without being dependent on an extremely high ratio of produced leukocytes to original stem cells. This extremely high ratio may be due to a systematic pathological deterioration of the mitotic maturation ability during the maturation process of the leuko-blastocysts. Consequently, restoration of the deterioration to the original mitotic maturation response of the normal leuko-blastocysts may be an essential event in achieving leukemia eradication, rather than persistent destruction of individual leukemic leukocytes.

Blast Crisis↗
PubMed2002

Physio-mitotic theory and a new concept of embryological differentiation.

According to the physio-mitotic theory described previously by the authors (10,11), general mitosis consists of two different types: essential duplication and converted maturation. In general embryological differentiation, progression for the most fundamental blastocysts of the three germ layers to the immature stem cells comprising functional organic tissues is dependent on the essential duplication mitosis. This mitosis replicates stem cells while gradually initiating latent cellularities whereas the converted maturation process merely amplifies these latent cellularlities by maturing the basic cells in differentiated functional end cells with a pre-determined life span. The differentiation from the three-germ layer to embryologically organized tissues is dependent on duplication mitosis while being regulated by interactions with maturation mitosis. Thus, the complicated embryonic differentiation must be established in each type of organic tissue. During the process, these two types of mitosiseach play an antagonistic role in the embryological development of the other. This is another application of the physio-mitotic theory.

Animals↗
PubMed2002

Leukemia eradication and the effect of maturation factor.

As described previously (1), the development of leukemia might be attributable to the deteriorated effect of a maturation factor on the relevant type of the leukemic leukocytes, rather than a certain cellular defect initiated in the individual leukemic leukocytes. Thus, the eradication of the leukemia should depend on re-establishing the effect of the maturation factor, rather than persistent destruction of individual leukemia leukocytes. The most powerful effect of the maturation factor may be exerted throughout the mitotic duplication process of the most immature fibro-blastocysts in an in vitro cell culture. Thus, to achieve leukemia eradication, this specific cell culture, which might indefinitely be duplicating the immature fibro-blastocysts in the lineage of leukemic leukocytes, should be investigated and developed. Additionally, a technical method of extracting the maturation factor for the maturation mitosis of leukemic leukocytes should be devised and developed in the future.

Animals↗