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Biomedical subjects

H Ito

Publications and source records attributed to H Ito.

At least 703 records · Page 39Linked to original sources
PubMed1998

GnRH-immunoreactive neuronal system in the presumptive ancestral chordate, Ciona intestinalis (Ascidian).

Gonadotropin-releasing hormone (GnRH) of the vertebrate brain, which has originally been identified as a peptidergic hypophysiotropic hormone, is now believed to act also as a neuromodulator. It has recently been shown that a vertebrate-like GnRH-gonadotropin system occurs in the urochordates, which are considered to be the presumptive ancestral chordate. In this paper, we examined the morphology of the GnRH neuronal system of ascidian, Ciona intestinalis, by immunocytochemistry and found many GnRH-immunoreactive neuronal cells and fibers in a specific surface area of the cerebral ganglion, along the inner wall of the dorsal blood sinus, as well as on the anterior surface of the ovary.

Animals↗
PubMed1998

Oxygen consumption and motility of mechanically unloaded myocardial slices.

We have recently established a new measurement system of myocardial O2 consumption per min (mVO2) of mechanically unloaded rat left ventricular (LV) slices (Yasuhara et al.: Am. J. Physiol. 270: H1063-H1070, 1996). Using this system, we have revealed that an increment in O2 consumption (delta mVO2) by electrical stimulation primarily represents mVO2 for Ca2+ handling in the excitation-contraction (E-C) coupling, though much smaller than that in the whole heart preparation. The much smaller delta mVO2 in the sliced myocardium than that in the whole heart is due to the much lower frequency of stimulation (60 bpm against 300 bpm). We consider that delta mVO2 does not contain mVO2 for residual crossbridge cycling from the results showing no effect of 2,3-butanedione monoxime on delta mVO2 despite the large decrease in mechanically unloaded contraction, which is expressed by the motility index. We also revealed that mVO2 without stimulation represents basal metabolism. The basal metabolism in rat myocardial slices, which is much higher than in other mammalian hearts, corresponds to that in the rat whole heart preparation. We finally obtained the results showing that sarcoplasmic reticulum (SR) Ca2+ pump blockers, thapsigargin and cyclopiazonic acid, did not reduce basal metabolic mVO2 but both of them reduced delta mVO2 maximally by 50-70% of control and markedly reduced the motility index. We conclude that myocardial O2 consumption (VO2) is composed of VO2 for E-C coupling and basal metabolism and does not contain VO2 for residual crossbridge cycling. Basal metabolic VO2 does not include VO2 for the SR Ca2+ pump, and at least two-thirds of VO2 for E-C coupling represents VO2 for the SR Ca2+ pump.

Animals↗
PubMed1998

Benign fibrous mesothelioma successfully treated by thoracoscope-assisted surgery: report of a case.

We report herein the case of an 84-year-old man in whom a benign fibrous mesothelioma (BFM) was successfully treated by thoracoscope-assisted surgery. In September 1996, the patient underwent a sigmoidectomy for colon cancer, soon after which a followup examination disclosed a coin lesion on his chest X-ray film. The patient was readmitted to our hospital in November 1996 for further investigation of this tumor. A chest computed tomography scan revealed a 3.5 x 3.0 cm homogeneous tumor arising from the pleura. A needle biopsy was performed under ultrasonographic guidance, and the specimen was histopathologically diagnosed as a BFM. In view of his poor respiratory function, the tumor was excised by thoracoscope-assisted surgery. This case report serves to demonstrate the benefits of thoracoscope-assisted surgery for such patients.

Aged↗
PubMed1998

Development of a non-invasive treatment system for urinary incontinence using a functional continuous magnetic stimulator (FCMS).

A system composed of a functional continuous magnetic stimulator (FCMS) and a saddle-type coil has been developed for non-invasive treatment of urinary incontinence, especially stress incontinence and urge incontinence. The FCMS conditions were as follows: 2 kW maximum electrical power consumption, 800 V maximum capacitor voltage, 720 microseconds pulsewidth (180 microseconds rise time), and 5-30 Hz frequency. A frequency between 5 and 10 Hz is used to treat urge incontinence and a frequency between 25 Hz and 30 Hz is used to treat stress incontinence. The coil (120 mm long, 90 mm wide and 50 mm thick) fits the most suitable region for this treatment, the region from the anus to the perineum. The coil is cooled to maintain a coil temperature between 20 and 25 degrees C so that it can be used efficiently and safely. In experiments with anaesthetised dogs, it was confirmed that the urethral pressure increased when the circumference of the perineum received continuous magnetic stimulation of 720 microseconds pulsewidth (180 microseconds rise time), 10 Hz frequency and about 520 V capacitor voltage. This result suggests that magnetic stimulation can be effective as a urinary incontinence therapy.

Animals↗
PubMed1998

Use of automated image registration to generate mean brain SPECT image of Alzheimer's patients.

UNLABELLED: The purpose of this study was to compute and compare the group mean HMPAO brain SPECT images of patients with senile dementia of Alzheimer's type (SDAT) and age matched control subjects after transformation of the individual images to a standard size and shape. METHODS: Ten patients with Alzheimer's disease (age 71.6 +/- 5.0 yr) and ten age matched normal subjects (age 71.0 +/- 6.1 yr) participated in this study. Tc-99m HMPAO brain SPECT and X-ray CT scans were acquired for each subject. SPECT images were normalized to an average activity of 100 counts/pixel. Individual brain images were transformed to a standard size and shape with the help of Automated Image Registration (AIR). Realigned brain SPECT images of both groups were used to generate mean and standard deviation images by arithmetic operations on voxel based numerical values. Mean images of both groups were compared by applying the unpaired t-test on a voxel by voxel basis to generate three dimensional T-maps. X-ray CT images of individual subjects were evaluated by means of a computer program for brain atrophy. RESULTS: A significant decrease in relative radioisotope (RI) uptake was present in the bilateral superior and inferior parietal lobules (p < 0.05), bilateral inferior temporal gyri, and the bilateral superior and middle frontal gyri (p < 0.001). The mean brain atrophy indices for patients and normal subjects were 0.853 +/- 0.042 and 0.933 +/- 0.017 respectively, the difference being statistically significant (p < 0.001). CONCLUSION: The use of a brain image standardization procedure increases the accuracy of voxel based group comparisons. Thus, intersubject averaging enhances the capacity for detection of abnormalities in functional brain images by minimizing the influence of individual variation.

Aged↗
PubMed1998

A comparison of Tc-99m HMPAO brain SPECT images of young and aged normal individuals.

The purpose of this study was to examine the normal distribution patterns of 99mTc-HMPAO (HMPAO) in young and aged normal individuals and to clarify differences between the distribution patterns of the two groups by means of an anatomical standardization technique. The tracer distribution was measured with HMPAO and SPECT in 18 normal subjects; age range 20-81 yrs. SPECT images were globally normalized by averaging whole brain radioactivity counts to 100 counts/voxel. The SPECT images for each subject were transformed into the standard brain anatomy by means of a computerized brain atlas, together with each subject's CT images. Mean and SD images for young (28.8 +/- 6.4 yrs) and aged groups (62.3 +/- 10.2 yrs) were then calculated on a voxel-by-voxel basis. Statistically significant differences between young and aged groups were observed in the relative tracer distribution patterns. In the aged group, relative decreases were found in the cortical areas of the frontal and temporal lobes, limbic areas and basal ganglia regions. The results, as visualized changes in tracer distribution patterns with aging, may contribute to more accurate clinical diagnosis.

Adult↗
PubMed1998

Role of the bcl-2/bax pathway in hepatocyte apoptosis during acute rejection after rat liver transplantation.

It is well established that hepatocytes undergo apoptotic cell death in the course of rejection of liver grafts. The present study was designed to investigate the role of the bcl-2/bax pathway in liver allograft tissue. Orthotopic liver transplantation was performed in three groups of rats: group 1, a syngeneic combination (Lewis to Lewis), group 2, an allogeneic combination (ACI to Lewis), and group 3, an allogeneic combination (ACI to Lewis) treated with 15-deoxyspergualin. The number of apoptotic cells identified by the TUNEL method in the grafted liver reflected the severity of acute rejection. In group 1, both bcl-2 mRNA and bax mRNA were expressed in trace amounts. In group 2, bcl-2 mRNA was slightly expressed while the expression of bax mRNA rose steadily. In group 3, bcl-2 mRNA expression levels remained similar to group 1, while bax expression levels exceeded those in group 1, but were less than in group 2. Expression of bcl-2 mRNA was stationary in comparison with expression of bax mRNA. Significantly higher levels of bax mRNA were expressed from day 4 in group 2 than in group 1 (on postoperative days 4, 6, and 8, P < 0.05, group 2 vs group 1). We also investigated bax protein and results consistent with the mRNA analysis data were obtained. These findings suggest that apoptotic cell death in liver allograft rejection is regulated, at least in part, by bax.

Acute Disease↗
PubMed1998

Expression of bcl-2 homologue mRNAs in rat liver allograft: rejection-induced cell apoptosis is associated with upregulation of bax and bcl-xs expression.

Apoptosis is considered to play an important role in rejection of organ transplants, although the precise mechanism has not been elucidated. In this study, we screened for the expression of bcl-2 homologues (bcl-2, bax, bcl-xl, and bcl-xs) and Fas ligand (FasL) by RT-PCR method in grafts during acute rejection in rats following liver transplantation. Both bax and bcl-xs (inducers of apoptosis) mRNA levels increased steadily in the allografted group from postoperative day (POD) 2 to 8, while no remarkable changes of bcl-2 and bcl-xl expression (inhibitors of apoptosis) were recognized. Significant induction of FasL gene expression was observed in the allografted group on POD 4 and expression gradually decreased thereafter, although minimal FasL mRNA expression was seen in isografts. Our results indicated, for the first time, that rejection-induced cell apoptosis is closely associated with upregulation of bax and bcl-xs expression besides FasL, but not with down-regulation of bcl-xl.

Animals↗
PubMed1998

Prolactin-secreting macroadenoma in a prepubertal girl.

Prolactin-secreting adenoma, which usually presents with amenorrhea and galactorrhea syndrome, is quite rarely diagnosed in the prepubertal age group. We reported a rare case of a prepubertal prolactin-secreting adenoma and discuss its clinical, radiological and histological features. An 8-year-old girl presented with headache, progressive visual deterioration and precocious puberty. The serum prolactin level was 57.8 ng/ml. Computerized tomography and magnetic resonance imaging revealed an invasive suprasellar tumor. The tumor was partially resected through an interhemispheric approach in a first operation, and residual tumor was resected through the right pterional approach in a second operation. The histological diagnosis was a prolactin-secreting adenoma with high cellular pleomorphism. The Ki-67 labeling index was 5.7%, indicating aggressive biological behavior. Postoperatively, the patient was prescribed bromocriptine as maintenance therapy, and the serum prolactin level became normalized. There is a tendency for diagnosis of a prepubertal prolactin-secreting adenoma to be delayed because there are no endocrinological manifestations. Therefore, the tumor tends to become larger and invasive. Although it is rarely experienced, a prolactin-secreting adenoma should be considered in the differential diagnosis of a large, invasive parasellar lesion in the prepubertal age group.

Bromocriptine↗
PubMed1998

Apoptotic cell death induced by local brain hyperthermia in a rat glioma model.

Hyperthermia has been shown to inhibit glioma growth both in vitro and in vivo, and has been reported to induce apoptosis of a variety of cells. We investigated the role of apoptosis in tumor cell death following hyperthermia in a rat glioma model representing human glioblastoma. Apoptotic cell death was evaluated by terminal deoxyribonucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) and hematoxylin and eosin (H & E) staining. We also examined c-Jun expression immunohistochemically. Apoptotic cell death in rat brain tumors that grew after implantation of C6 glioma cells showed regional differences. In all rats, apoptotic cells, characterized by extreme chromatin condensation and fragmented nuclei with apoptotic bodies in H & E-stained sections, were observed in the gliomas' necrotic cores. TUNEL-positive cells were observed in the border zones between necrotic and vital tumor cells. Before hyperthermia, TUNEL-positive cells were sporadically distributed in the vital tumor tissue. After hyperthermia, the number of TUNEL-positive cells in the peripheral region of the tumor mass increased significantly, reached a peak after 6 h and returned to the basal level within 24 h (P < 0.01). C-Jun protein immunoreactivity was not observed in the cells at the tumor periphery. These data indicate that significantly apoptotic cell death unrelated to c-Jun expression occurs after hyperthermia, and that this form of cell death may be the mechanism of tumor regression following hyperthermia treatment of intracranial gliomas.

Animals↗
PubMed1998

Unicompartmental knee arthroplasty for medial gonarthrosis: 5 to 9 years follow-up evaluation of 77 knees.

A total of 77 knees in 60 consecutive patients were operated on for medial gonarthrosis using a cemented porous coated anatomical (PCA) unicompartmental knee arthroplasty. Their average age was 71.3 years; 11 were men and 49 women. Clinically, the results in 67 knees were rated as being good to excellent, with mean preoperative and postoperative flexion of 123 and 122 deg, respectively. No deep infections or deep venous thrombosis occurred, but there was one dislocation of the femoral component. Overall clinical and radiographic results were satisfactory in 88% at 7.0 years' follow-up. Kaplan-Meier survivorship analysis indicated that the failure rate of unicompartmental knee arthroplasty was 12% at average follow-up. In patients aged 70 years or more, unicompartmental knee arthroplasty for medial gonarthrosis should be considered an excellent alternative to high tibial osteotomy.

Aged↗
PubMed1998

Fracture of the axis after dome-like cervical laminoplasty.

We describe a case of fracture of the axial neural arch that occurred after a dome-like cervical laminoplasty and caused dural compression. Cervical laminoplasty with dome-like laminoplasty of the axis was performed on a patient with cervical myelopathy due to ossification of the posterior longitudinal ligament extending from C2 to C6. After temporary neurological remission, the patient experienced unanticipated neurological deterioration with posterior cervical pain. Radiographs, magnetic resonance imaging and computed tomography of the cervical vertebrae showed a fractured axial lamina that was compressing the cervical cord. After total axial laminectomy, permanent neurological improvement was obtained. Our experience suggests that care should be taken to avoid an excessive dome-like laminoplasty and that the possibility of axial fracture should be borne in mind.

Aged↗
PubMed1998

Inhibition of the neuronal nicotinic receptor-mediated current by kappa opioid receptor agonists in PC12 cells.

The authors studied effects of opioid receptor agonists on neuronal nicotinic-receptor-mediated current in PC12 cells using whole-cell current recording. At 1 microM, [d-Ala, N-Me, Phe, Gly-ol]- enkephalin (DAMGO), a selective micro receptor agonist, or 10 microM methionine-enkephalin, a micro and delta receptor agonist, did not inhibit the current elicited by 30 microM nicotine significantly. Dynorphin A (1-17) (0.1-1 microM), an endogenous kappa receptor agonist, and U50488 (0.1-10 microM), a non-peptide selective kappa receptor agonist, depressed the nicotine-induced current reversibly in a dose-dependent manner. They accelerated the current decay, resulting in greater effects on the non-desensitized current than the peak current. These effects were not affected by nor-binaltrophimine, a selective kappa receptor antagonist, or by inclusion of guanosine 5'-O-(2-thiobiphosphate) (GDP[beta-S]), a GTP binding protein blocker, into the pipette solution. These results demonstrate that two kappa opioid receptor agonists, dynorphin A (1-17) and U50488, inhibit neuronal nicotinic-receptor-mediated current without the involvement of opioid receptors or GTP binding proteins. The acceleration of the current decay suggests a direct action on nicotinic receptors such as open channel block, or augmentation of desensitization. Modulation of neuronal nicotinic receptors by dynorphins may play a role in some areas where dynorphin release sites and neuronal nicotinic receptors are colocalized.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1998

Frequent occurrence of apoptosis is an early event in the oncogenesis of human gastric carcinoma.

We examined the relationship between apoptosis and the progression of human gastric carcinoma. Studies were conducted on a total of 88 surgically removed stomachs, comprising 26 minute (less than 5 mm in diameter), 29 early (limited to the mucosal and submucosal layer) and 33 advanced carcinomas. Apoptotic cells were visualized by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end labelling (TUNEL). Serial sections were immunostained for p53 and Ki-67. The mean apoptotic indices (AI: percentage of TUNEL signal positive cells) of minute, early, and advanced carcinomas were 4.1 +/- 0.6, 3.8 +/- 1.2, and 4.0 +/- 1.2 in 46 well differentiated carcinomas, and 2.1 +/- 0.5, 2.7 +/- 0.9, and 2.2 +/- 1.1 in 42 poorly differentiated carcinomas, respectively. Similarly, the mean Ki-67 labelling indices (KI) were 39.2 +/- 7.8, 47.2 +/- 12.8, 52.6 +/- 13.1 in the former, and 35.0 +/- 9.3, 36.9 +/- 10.3, and 40.0 +/- 9.2 in the latter, respectively. Both mean AI and mean KI were significantly higher in well differentiated than in poorly differentiated carcinomas (P < 0.05). However, the value of mean AI did not differ among minute, early, and advanced carcinomas in either histological type, while KI increased gradually with tumour progression. The frequency of nuclear p53 expression did not differ among the three categories, implying that the gene mutation is an early event in gastric carcinogenesis. There was no statistical significance between nuclear p53 expression and mean AI. These results suggest that the progression of gastric cancer is defined by a gradual increase of proliferative activity and constant occurrence of apoptosis and that naturally occurring apoptosis is induced predominantly via a p53-gene-independent pathway.

Adenocarcinoma↗
PubMed1998

Mesangial cell activation in the collagenofibrotic glomerulonephropathy. Case report and review of the literature.

Collagenofibrotic glomerulonephropathy is a new disease entity of unknown pathogenesis, which is characterized by the deposition of type III collagen within the mesangial matrix. We have investigated a case in which many mesangial cells in the type III collagen-deposited glomeruli were alpha-smooth muscle actin (ASMA) positive and showed an increase of subplasmalemmal filaments, indicating the activation and myofibroblastic transformation. It is suggested that the activated mesangial cells may synthesize the type III collagen deposited in the subendothelial space and mesangial matrix.

Actins↗
PubMed1998

Carcinosarcoma of the colon: report of a case and review of the literature.

We report a case of carcinosarcoma in the transverse colon in a 60-year-old woman. She was admitted to our hospital for further examination of occult blood in October, 1995. Colonoscopy disclosed an elevated lesion with ulceration in the transverse colon, and she underwent right hemicolectomy. Histopathological examination revealed the tumor to consist of both carcinomatous and sarcomatous elements, the latter being more predominant. Immunohistochemistry revealed vimentin immunoreactivity in most of the sarcomatous cells, and S-100 and myoglobin in a few carcinomatous cells. Distinct carcinomatous features were noted in one superficial portion of the tumor, and these carcinomatous cells showed immunoreactivity for epithelial membrane antigen. The patient is alive 14 months after surgery without evidence of recurrence. To our knowledge, this is the fourth reported case of carcinosarcoma of the colon. Our review of the literature disclosed poor prognosis in colonic carcinosarcoma.

Carcinosarcoma↗
PubMed1998

Serum protein exudation in chronic subdural haematomas: a mechanism for haematoma enlargement?

A study was conducted to investigate the role of serum protein exudation in the aetiology of chronic subdural haematoma (SDH). Scintigraphy after intravenous injection of 99mTc-labelled human serum albumin (HSA) was performed in three patients with chronic SDH and a patient with subdural effusion. In another 60 haematomas, the amounts of total protein and albumin as indices of serum exudation were measured, and then compared among low-density, iso-density and high-density haematomas. Accumulation of 99mTc-HSA in the haematoma cavity was seen 6 h after isotope injection and became more evident at 24 h. However, the protein concentrations and albumin ratios in the haematomas exhibited a reciprocal relationship, suggesting that not all the protein in the haematomas was derived from serum exudation. The higher the total protein concentration in the haematoma became, the higher the haematoma density which was observed on CT. The albumin concentration in low-density haematomas was lower than that in iso-density and high-density haematomas, whereas no significant difference was seen between the latter two haematoma types. These results provide morphological evidence for serum protein exudation into the haematoma cavity, and therefore it is possible that serum protein exudation plays a role in the progression of chronic SDH and is related to changes in haematoma density on CT.

Adult↗