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Biomedical subjects

H Sakamoto

Publications and source records attributed to H Sakamoto.

At least 127 records · Page 7Linked to original sources
PubMed2000

Positron emission tomographic imaging of acoustic neuromas.

Positron emission tomography (PET) examination with both [11C]methyl-l-methionine (Met) and [18F]fluoro-2-deoxyglucose (FDG) was performed in the same patients with acoustic neuroma wherever possible in order to compare the usefulness of the two methods. The study included six patients who visited the Osaka City University Hospitals, between April 1994 and October 1998, for complaints associated with acoustic neuroma. All patients were examined by magnetic resonance imaging (MRI) and Met-PET. Four patients were examined by FDG-PET. The tumor's region of highest accumulation was selected as the region of interest; the tumor/normal ratio (T/N ratio) was defined as the ratio of radioisotope counts for tumor and normal gray matter. All tumors in this series were detected by MRI. In the Met-PET images, four tumors were easily identified, with a high T/N ratio. However, two tumors could not be identified using Met-PET. On FDG-PET, no cases could be identified. The T/N ratio for the four patients with positive Met-PET findings averaged 1.694 +/- 0.266. PET, especially Met-PET, is a powerful means of examination providing functional information on tumors in acoustic neuroma. Met-PET may therefore be useful for acoustic neuroma, which is known to proliferate slowly, as for malignant tumors, in evaluating the proliferating potential of a tumor, in determining patients in whom to perform radiological treatment and in monitoring post-treatment progress.

Adult↗
PubMed2000

Eradication of hepatitis C virus 1b by interferon in a health care worker with acute hepatitis following needlestick transmission from a patient with chronic hepatitis C unresponsive to interferon.

Hepatitis C virus (HCV) was successfully eradicated by a short course of interferon (IFN) therapy in a nurse with acute HCV infection from a needlestick accident. The source patient had chronic hepatitis C and was a nonresponder to IFN therapy. The HCV genotype was 1b in patients, and a single point mutation (H-->R in amino acid 2218) was observed in the IFN sensitivity-determining region of the nonstructural 5A gene, in comparison with sequences of HCV-J, in HCV RNA from both the source patient (before and after IFN therapy) and the recipient (before IFN therapy). Though the strain transmitted was believed to be IFN-resistant in the patient with chronic hepatitis, the patient with acute hepatitis had a sustained response.

Acute Disease↗
PubMed2000

Granulation of acetaminophen by a rotating fluidized-bed granulator.

The purpose of this research was to evaluate the use of a rotating fluidized-bed granulator to produce acetaminophen granules with sufficient binding force between particles and good plasticity in tablets. Ethenzamide and ascorbic acid were used to compare the relationship between granulation and the sample wetness. It was revealed that a blade rotation rate of 300 rpm, inlet air flow rate of 42 m3/hr, and spraying pressure of 1.5 kg/cm3 produced tablets with the best properties. The granule and tablet properties of ethenzamide and ascorbic acid were compared to those of acetaminophen. These compounds showed different wetting behaviors with water and different compression behaviors. With an increase in medicament content, tablet hardness increased except for the ascorbic acid formulation. Capping and sticking were observed in acetaminophen and in ascorbic acid, respectively, and acetaminophen and ethenzamide showed prolonged disintegration time.

Acetaminophen↗
PubMed2000

Uterine horn torsion in two non-gravid bitches.

Uterine torsion secondary to sacculation of the uterine horns was diagnosed in two non-gravid bitches which were presented with anorexia, polydipsia and an acutely swollen abdomen. On the basis of the radiological and ultrasonographic findings, which indicated the presence of an enlarged spherical or tubular structure filled with hypoechoic material in the caudal abdomen, a tentative diagnosis of pyometra was made. Exploratory laparotomy revealed unilateral uterine horn torsion along the longitudinal axis, with bilateral fluid-filled sacculations. Ovariohysterectomy was performed in both cases. Pathological examination of the uteri demonstrated haematometra in one dog and pyometra in the other.

Animals↗
PubMed2000

Genetic aberrations detected by comparative genomic hybridization in ovarian clear cell adenocarcinomas.

Genetic abnormalities were detected by comparative genomic hybridization (CGH) in 12 ovarian clear cell adenocarcinomas. DNA sequence copy number abnormalities (CNAs) occurring in more than 20% of the cancers included increased copy numbers of 8q11-q13, 8q21-q22, 8q23, 8q24-qter, 17q25-qter, 20q13-qter and 21q22-qter and reduced copy numbers of 19p. Increases in copy numbers of 8q11-q13, 8q21-q22, 8q23 and 8q24-qter occurred more frequently in disease-free patients than in recurrent/non-surviving patients (p < 0.05). However, increases in copy numbers of 17q25-qter and 20q13-qter occurred more frequently in recurrent/non-surviving patients than in disease-free patients (p < 0.05). Furthermore, increases in copy numbers of 17q25-qter and 20q13-qter occurred together (p < 0.05). Additionally, there were negative correlations between increases in copy numbers of 8q21-q22 and 17q25-qter, and between 8q21-q22 and 20q13-qter (p < 0.05). It appears that ovarian clear cell adenocarcinomas can be classified into two subtypes, one being cancer with an increase in copy numbers of 8q and the other being cancer with increases in copy numbers of 17q25-qter and 20q13-qter.

Adenocarcinoma, Clear Cell↗
PubMed2000

Endovascular treatment of huge cervicofacial hemangioma complicated by Kasabach-Merritt syndrome.

A 2-month-old girl with a huge cervicofacial hemangioma complicated by Kasabach-Merritt syndrome was presented. Two weeks corticosteroid treatment was ineffective, and deterioration of coagulation parameters and compromise of the airway and left vision due to huge hemangioma prompted use of endovascular treatment. Transfemoral arterial embolization using polyvinyl alcohol particles resulted in rapid clinical improvement. Endovascular treatment should be considered as an important therapeutic option for hemangioma complicated by Kasabach-Merritt syndrome.

Anemia, Hemolytic↗
PubMed2000

Basal meningoencephalocele, anomaly of optic disc and panhypopituitarism in association with moyamoya disease.

Basal meningoencephalocele is frequently associated with midfacial anomaly, optic disc anomaly, brain anomaly, cerebrospinal fluid rhinorrhea, chiasma syndrome, and endocrinologic disturbance. The combination of basal meningoencephalocele and moyamoya disease is extremely rare. A 29-year-old man had basal meningoencephalocele (transsphenoidal type), anomaly of the optic disc (morning glory syndrome), panhypopituitarism and moyamoya disease. The patient was treated by hormone replacement, but surgical intervention was not required. Basal meningoencephalocele and moyamoya disease are a possible combination of the diseases.

Adult↗
PubMed2000

Existence of galanin in lumbosacral sympathetic ganglionic neurons that project to the quail uterine oviduct.

Oviposition in birds is conducted by vigorous contractions of the uterine oviduct. We recently isolated an oviposition-inducing peptide that was identified as avian galanin from mature quail oviducts. This peptide was localized in neuronal fibers terminating in muscle layers in the uterine oviduct and evoked vigorous uterine contractions through binding to receptors located in the uterus. However, no cell bodies that express avian galanin were detected in the uterus or other oviduct regions. To understand the control mechanism of avian oviposition by galanin, we identified the neurons that synthesize galanin and project to the uterus with the combination of retrograde labeling with neurobiotin and immunocytochemistry for galanin in mature Japanese quails. Retrograde labeling with neurobiotin from the uterus revealed that lumbosacral sympathetic ganglionic neurons located in the uterine side projected their axons to the uterine muscle layer. Abundant elementary granules were observed in somata of the retrogradely labeled sympathetic ganglionic neurons, suggesting that labeled neurons may function as a neurosecretory cell. Immunocytochemical analysis with the antiserum against avian galanin showed an intense immunoreaction restricted to somata of the retrograde-labeled ganglionic neurons. Preabsorbing the antiserum with avian galanin resulted in a complete absence of the immunoreaction. Competitive enzyme-linked immunosorbent assay using antigalanin serum confirmed that avian galanin existed in the sympathetic ganglionic neurons. Expression of the avian galanin messenger RNA in the neurons was further verified by Northern blot analysis. In addition, both avian galanin and its messenger RNA in the neurons were highly expressed in mature birds, unlike in immature birds. These results suggest that lumbosacral sympathetic ganglionic neurons innervating the uterine muscle produce avian galanin in mature birds. Because this peptide acts directly on the uterus to evoke oviposition through a mechanism of the induction of vigorous uterine contraction, galaninergic innervation of the uterine oviduct may be essential for avian oviposition.

Animals↗
PubMed2000

Tyrosine kinase and phosphatidylinositol 3-kinase activation are required for cyclic adenosine 3',5'-monophosphate-dependent potentiation of deoxyribonucleic acid synthesis induced by insulin-like growth factor-I in FRTL-5 cells.

In previous studies, we showed that pretreatment of rat FRTL-5 thyroid cells with TSH, or other agents that increased intracellular cAMP, markedly potentiated DNA synthesis in response to insulin-like growth factor-I (IGF-I). In addition, we found that TSH pretreatment caused an increase in tyrosine phosphorylation of intracellular proteins including an unidentified 125-kDa protein that was well correlated with the TSH-potentiating effect on DNA synthesis induced by IGF-I. These results suggested that cAMP amplified IGF-I-dependent signals for cell growth through changes of cAMP-dependent tyrosine phosphorylation. The present studies were undertaken to determine how tyrosine kinase activation followed by an increase in tyrosine phosphorylation is required for cAMP-dependent potentiation of DNA synthesis induced by IGF-I in this cell line. First of all, we measured tyrosine kinase or protein-tyrosine phosphatase activities in the cell lysates by the in vitro assay. Chronic treatment with TSH or (Bu)2-cAMP stimulated tyrosine kinase activity in the particulate fraction and protein-tyrosine phosphatase activity in the soluble fraction, suggesting that tyrosine kinase plays more important roles for a cAMP-dependent increase in tyrosine phosphorylation of intracellular proteins. The increased tyrosine kinase activity was sensitive to genistein, a potent tyrosine kinase inhibitor. Genistein abolished both the cAMP-dependent increase in tyrosine phosphorylation of the 125-kDa protein and the enhanced DNA synthesis induced by IGF-I in a similar concentration-dependent manner. The only tyrosine-phosphorylated protein associated with the p85 regulatory subunit of phosphatidylinositol (PI) 3-kinase in response to cAMP was 125 kDa. In addition, we found that PI 3-kinase activity bound to p85 subunit significantly increased after (Bu)2cAMP treatment. These results suggested that cAMP stimulates PI 3-kinase through tyrosine phosphorylation of the 125-kDa protein. We then measured DNA synthesis in cells pretreated for 24 h with TSH or (Bu)2cAMP in the absence or presence of LY294002, a PI 3-kinase inhibitor, followed by treatment with IGF-I for 24 h. Presence of LY294002 during TSH or (Bu)2cAMP pretreatment completely abolished cAMP-dependent potentiation of DNA synthesis induced by IGF-I. These results suggest that in FRTL-5 cells cAMP activates genistein-sensitive tyrosine kinases that in turn activate PI 3-kinase activity. These mechanisms appear to be necessary for cAMP-dependent potentiation of the DNA synthesis induced by IGF-I.

Animals↗
PubMed2000

Involvement of NF-kappaB in the protection of cell death by tumor necrosis factor in L929 derived TNF resistant C12 cells.

The Tumor necrosis factor (TNF)-resistant C12 cell line was established by continuous exposure of a toxic concentration of TNF to parental murine fibrosarcoma L929 cells. Introduction of the cytosolic phospholipase A2 (cPLA2) gene to C12 cells resulted in restoration of the TNF sensitive phenotype (CPL4 cells). DNA ladder formation and nuclear condensation by TNF exposure suggested that TNF induced apoptotic cell death in L929, C12 and CPL4 cells. TNF-induced activation of transcription factor nuclear factor-kappaB (NF-kappaB) was observed in all 3 cell lines. The activation reached the maximum level at 30 min after the exposure to TNF and thereafter declined slowly. The amount of activated NF-kappaB in C12 cells was about twice as high as that of L929 cells with either dose of TNF tested in this study. It was found that C12 cells expressed latent NF-kappaB twice that of L929 cells. This abundance of latent NF-kappaB would provide a higher response of NF-kappaB in C12 cells. Pretreatment with the known potent NF-kappaB inhibitor pyrolidine dithiocarbamate (PDTC) profoundly suppressed the activation of NF-kappaB induced by TNF and potentiated TNF cytotoxicity in all 3 cell lines. These results are consistent with the recently found anti-apoptotic action of NF-kappaB and suggest that NF-kappaB acts as an acquired TNF resistant factor in C12 cells.

Animals↗
PubMed2000

The risk of contrast media-induced ventricular fibrillation is low in canine coronary arteriography with ioxilan.

Previous studies have proposed that sodium supplement to nonionic contrast media (CM) can decrease the risk of ventricular fibrillation (VF). This study was designed to compare the occurence of VF induced by ioxilan (containing 9 mmol/LNa+) with other nonionic CMs. After wedging a catheter in the right coronary artery, test solutions including ioxilan, ioversol, iomeprol, and iopromide were infused for 30 sec at the rate of 0.4 ml/sec or until VF occurred. Then, incidence of VF, contact time (i.e. the time required to produce VF), and QTc were measured. Also, the CMs other than ioxilan were investigated at sodium levels adjusted to 9 and 20 mmol/L Na+. The incidence of VF with ioxilan (0%) was the lowest of all. In the other CMs, the incidence decreased in accordance with increase of sodium. Iomeprol and iopromide showed significant reduction of VF incidence at the sodium level of 20 mmol/L. The higher sodium supplements also prolonged the contact times. The increase of QTc was the greatest in ioxilan. Ioxilan has the least arrythmogenic property among the current low-osmolality nonionic CMs. This property might be attributable to an optimal sodium concentration of 9 mmol/L in the CM.

Animals↗
PubMed2000

Tibiofemoral movement 3: full flexion in the living knee studied by MRI.

We studied active flexion from 90 degrees to 133 degrees and passive flexion to 162 degrees using MRI in 20 unloaded knees in Japanese subjects. Flexion over this arc is accompanied by backward movement of the medial femoral condyle of 4.0 mm and by backward movement laterally of 15 mm, i.e., by internal rotation of the tibia. At 162 degrees the lateral femoral condyle lies posterior to the tibia.

Adult↗
PubMed2000

Collaborative work to evaluate toxicity on male reproductive organs by repeated dose studies in rats 5). Effects of repeated doses of flutamide for 2 and 4 weeks.

Flutamide, a nonsteroidal antiandrogen, was administered orally to 8-week (for the 2 week study) and 6-week-old (for the 4 week study) male Crj:CD(SD) rats at dose levels of 0 mg/kg, 60 mg/kg and 200 mg/kg daily for 2 weeks or 4 weeks in order to determine whether a 2 week treatment period is sufficient for detection of drug effects on the male reproductive system. Flutamide treatment for 4 weeks resulted in decreased organ weights of the epididymides and prostate, decreased sperm counts and Leydig cell proliferation in the testes at 60 mg/kg and 200 mg/kg. Decreased sperm motility and histological lesions in the seminiferous tubules were observed at 200 mg/kg. Flutamide treatment for 2 weeks decreased organ weight of epididymides and prostate and caused Leydig cell proliferation in the testes at 60 mg/kg and 200 mg/kg. Decreased sperm counts and sperm motility, and histological lesions in seminiferous tubules were observed at 200 mg/kg. The results of this study showed that 2 weeks treatment with flutamide causes histological lesions of testes and disorders of sperm parameters similar to those observed with 4 weeks treatment, indicating that 2 weeks treatment is sufficient for detection of effects of flutamide on the male reproductive system.

Administration, Oral↗
PubMed2000

Evaluation of collagenase-induced mitral valve regurgitation in dogs.

OBJECTIVE: To investigate the hemodynamic changes induced by injecting collagenase into the mitral valve to induce mitral valve regurgitation (MVR) in dogs. ANIMALS: 9 healthy Beagles. PROCEDURE: Dogs were randomly assigned to 3 groups: control (saline [0.9% NaCl] solution; n = 3), single collagenase injection (C1; 3), and 2 collagenase injections (C2; 3). Open-heart surgery was performed, and saline or collagenase solutions were injected into the mitral valve. Before and weekly for 11 weeks after surgery, radiography, echocardiography, and phonocardiography were performed. Mean pulmonary arterial pressure and mean pulmonary arterial wedge pressure (mPAWP) were measured before and 11 weeks after surgery. Postmortem examinations were performed after dogs were euthanatized. RESULTS: No changes were detected in the control group during the 11-week follow-up period. A systolic murmur and MVR developed 1 week after surgery in groups C1 and C2. The murmur changed from a protosystolic to a pansystolic murmur, and left atrial diameter and the left atrial-to-aortic root diameter ratio increased with time. Mean pulmonary arterial pressure and mPAWP were greater 11 weeks after surgery in groups C1 and C2, compared with presurgery values. During necropsy, tissue loss was detected in the mitral valve at the site of collagenase injection. Degree of regurgitation corresponded to lesion size. CONCLUSIONS AND CLINICAL RELEVANCE: Injection of collagenase into the mitral valve of healthy dogs induced MVR, and dogs with MVR developed progressive hemodynamic changes without acute overload. Collagenase-induced MVR may be an appropriate model for evaluation of prognostic markers of idiopathic MVR in dogs.

Animals↗
PubMed2000

A case of an aberrant branch from the posterior brachial cutaneous nerve to the latissimus dorsi: a vestigeal part of the dorsoepitrochlearis?

During dissection, an aberrant muscular nerve to the small part of the latissimus dorsi arising from the posterior brachial cutaneous nerve was found. Based on the findings of the form and the innervation, the small part is considered to be a vestige of the dorsoepitrochlearis in mammals. It is suggested that the posterior brachial cutaneous nerve is derived from the nerve to the dorsoepitrochlearis (Kasai et al., 1989, Acta Anat Nippon 64: 255-266). This case may be indirect evidence indicating one of the patterns of development of cutaneous nerves in man.

Aged↗
PubMed2000

The janus kinase inhibitor, Jab/SOCS-1, is an interferon-gamma inducible gene and determines the sensitivity to interferons.

The Janus family of protein tyrosine kinases (JAKs) and STAT transcription factors regulate cellular processes involved in cell growth, differentiation, and transformation through their association with cytokine receptors. The CIS family of proteins (also referred as the SOCS or SSI family) has been implicated in the regulation of signal transduction by a variety of cytokines. Among them, we have shown that JAB/SOCS-1 is strongly induced by interferon-gamma and forced expression of JAB/SOCS-1I conferred cells interferon resistance. This resistance was caused by inhibition of JAK1 and JAK2 activation in response to IFNgamma. Moreover, recent detailed analysis of JAB/SOCS-1 knockout mice revealed that JAB/SOCS-1 is indeed a "negative feedback regulator" that determine the sensitivity of cells to IFNgamma. Using in vitro mutagensis, we defined a functional structure of JAB/SOCS-1 and proposed a mechanism for how JAB inhibits JAK kinase activity.

3T3 Cells↗
PubMed2000

[Depression during interferon therapy in renal cell cancer patients--comparison with chronic hepatitis C patients].

BACKGROUND AND PURPOSE: Depression is well known as one of the psychiatric complications of interferon (IFN) therapy in patients with chronic active hepatitis C. We compared the psychiatric status during interferon therapy between patients with renal cell cancer (RCC) and those with chronic active hepatitis C. METHODS: The psychiatric status of 40 patients with renal cell cancer, 36 who were subjected to radical nephrectomy and 4 who were not because of the presence of distant metastasis and other complicated underlying diseases, was assessed by psychiatrists before and at 2, 4, 12 and 24 weeks after the start of IFN therapy according to the major depressive episode diagnostic criteria listed in the DSM-III-R and the Hamilton Depression Scale (HDS). The mental aspect was measured using the Eysenk Personality Questionnaire (EPQ) before IFN therapy, and the results were compared with those obtained in 85 hepatitis C patients evaluated according to the same protocol for psychiatric assessment. RESULTS: Eight of the 40 patients were diagnosed as having depression before IFN therapy and 5 of them became even more depressed 2 weeks after the start of IFN therapy. Nine patients were found to be depressed after the start of IFN therapy, 7 of them were diagnosed before 4 weeks of therapy. All the patients needed treatment for depression: discontinuation of IFN therapy in 4, decrement of the IFN dose in 8, and psychiatric drug medication in 13. The patients who suffered from depression had significantly higher scores in neuroticism (EPQ) before IFN therapy than those who did not become depressed. There was no difference in age, sex or cancer stage between the two groups. The occurrence of depression in RCC patients was the same as that observed in hepatitis C patients receiving IFN therapy. But in RCC patients the depressive state was diagnosed earlier and was more severe than that observed in hepatitis C patients. CONCLUSION: Urologists should be aware of the psychiatric symptoms of RCC patients under IFN therapy just as in hepatitis patients. The depression in RCC patients was considered to be related to the cancerous disease itself which may explain its higher degree of severity, as compared to hepatitis C patients.

Aged↗