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Biomedical subjects

Y Mori

Publications and source records attributed to Y Mori.

At least 217 records · Page 12Linked to original sources
PubMed2000

Radioimmunoassay for orexin A.

A radioimmunoassay for orexin A has been developed. Anti-orexin A antiserum was raised in New Zealand white rabbits immunized with a conjugate of synthetic orexin A with bovine serum albumin. This antibody did not crossreact with orexin B, hypothalamic hormones, pituitary hormones, neuropeptides or gut hormones. Radioiodination of orexin A was performed with the chloramin T method, followed by purification of radioiodinated material on Sephadex G-25 column. Orexin A was extracted from tissues using acid-acetone. The assay was performed with a double antibody system. The dilution curve of acid-acetone-extracts of rat hypothalamus in the radioimmunoassay system was parallel to the standard curve. The recovery of tissue orexin A was about 80%,and the intra-assay and inter-assay variations were 5.2% and 7.8%, respectively. Orexin A was found in the hypothalamus, cerebrum and testis. These data suggest that this assay system is suitable for the measurement of tissue orexin A and that orexin A is found in the central nervous system and testis.

Animals↗
PubMed2000

Radiosurgery for bilateral neurinomas associated with neurofibromatosis type 2.

OBJECTIVE: The clinical course of bilateral acoustic tumors associated with neurofibromatosis (NF2) is generally troublesome, and no definite treatment strategy has been established. Follow-up results of bilateral acoustic tumors after radiosurgery are reported herein. METHODS: The current indications for radiosurgery are 1) a growing tumor less than 30 mm in mean diameter, 2) the ipsilateral ear has no serviceable hearing, and 3) there is risk of brain stem compression or brain stem dysfunction. Twenty cases of bilateral acoustic tumors were treated with the gamma knife, including 7 males and 13 females. The mean age was 38.2 years and the mean tumor size 24.4 mm. The tumors were treated with mean maximum and marginal doses of 26.8 Gy and 13.0 Gy, respectively. Among them, 12 patients had profound hearing loss in the ipsilateral (treated) ear, but the other 8 had serviceable hearing. RESULTS: Tumors treated with radiosurgery showed central necrosis in 60% of the cases at 6 months and in 70% at 9 months after radiosurgery. Thereafter, the tumors often demonstrated slow regression. The rate of tumor shrinkage was 20% at 12 months, 35% at 24 months, and almost 60% at 36 months. At the last follow-up (mean 33.6 months), the tumors demonstrated shrinkage in 50% and tumor control in 100%. The contralateral tumors were stable in 12 (60%) and enlarged in 8 (40%). Preservation of serviceable hearing ipsilaterally was obtained in 33.3%. Deterioration of ipsilateral facial nerve function, either in the natural course or as a complication, occurred in 10%. CONCLUSIONS: Because of good tumor control and tumor shrinkage as well as an acceptable complication rate, radiosurgery should be incorporated in the treatment strategy for bilateral acoustic tumors associated with NF2.

Adolescent↗
PubMed2000

Long-term effect of angiotensin-converting enzyme inhibitor in volume overloaded heart during growth: a controlled pilot study.

OBJECTIVES: This study examined whether long-term therapy with an angiotensin-converting enzyme (ACE) inhibitor reduces excessive increases in left ventricular (LV) mass as well as volume in growing children with aortic regurgitation or mitral regurgitation. BACKGROUND: The ACE inhibitor reduces volume overload and LV hypertrophy in adults with aortic or mitral regurgitation. METHODS: This study included 24 patients whose ages ranged from 0.3 to 16 years at entry to the study. On echocardiography, we measured LV size, systolic function and mass. After obtaining baseline data, patients were allocated into two groups. Twelve patients were given an ACE inhibitor (ACE inhibitor group), and 12 patients were not (control group). Echo parameters were again assessed after an average 3.4 years of follow-up. RESULTS: Left ventricular parameters at baseline in the two groups were similar. The Z value of LV end-diastolic dimensions decreased from +0.82 +/- 0.55 to +0.57 +/- 0.58 in the ACE inhibitor group, whereas it increased from +0.73 +/- 0.85 to +1.14 +/- 1.04 in the control group (mean change -0.25 +/- 0.33 for the ACE inhibitor group vs. +0.42 +/- 0.48 for the control group, p = 0.0007). The mass normalized to growth also reduced from 221 +/- 93% to 149 +/- 44% of normal in the ACE inhibitor group and increased from 167 +/- 46% to 204 +/-59% of normal in the control group (mean change -72 +/- 89% of normal for the ACE inhibitor group vs. +37 +/- 35% of normal for the control group, p = 0.0007). CONCLUSIONS: Long-term treatment with ACE inhibitors is effective in reducing not only LV volume overload but also LV hypertrophy in the hearts of growing children with LV volume overload.

Adolescent↗
PubMed2000

The I-II loop of the Ca2+ channel alpha1 subunit contains an endoplasmic reticulum retention signal antagonized by the beta subunit.

The auxiliary beta subunit is essential for functional expression of high voltage-activated Ca2+ channels. This effect is partly mediated by a facilitation of the intracellular trafficking of alpha1 subunit toward the plasma membrane. Here, we demonstrate that the I-II loop of the alpha1 subunit contains an endoplasmic reticulum (ER) retention signal that severely restricts the plasma membrane incorporation of alpha1 subunit. Coimmunolabeling reveals that the I-II loop restricts expression of a chimera CD8-I-II protein to the ER. The beta subunit reverses the inhibition imposed by the retention signal. Extensive deletion of this retention signal in full-length alpha1 subunit facilitates the cell surface expression of the channel in the absence of beta subunit. Our data suggest that the beta subunit favors Ca2+ channel plasma membrane expression by inhibiting an expression brake contained in beta-binding alpha1 sequences.

Animals↗
PubMed2000

Effect of portal hypertension caused by chronic high venous pressure on small-intestinal sugar absorption.

The effect of portal hypertension and chronic high venous pressure on the absorption of the small intestine was examined by constricting the suprahepatic and subdiaphragmatic inferior vena cava in rats. A group of rats with the constricted suprahepatic and subdiaphragmatic inferior vena cava comprised group 1 (n = 9) and another group of rats with only laparotomy comprised group 2 (n = 9). Two months after the operation, sugar absorption and other parameters were measured. The blood pressures of the infrahepatic inferior vena cava and the portal vein 8 wk after the operation in group 1 were significantly higher than those in group 2. The results of D-xylose absorption tests showed that the amount of excreted D-xylose in urine in group 1 was significantly lower than that of group 2, but the D-xylose everted sac test showed no significant differences between the two groups. The glucose everted sac test showed that the amount of glucose absorption in group 1 was significantly lower than that in group 2. These findings suggest that chronic high venous pressure caused by constriction of suprahepatic inferior vena cava may lead to sugar malabsorption. We conclude that portal hypertension with high venous pressure below the diaphragm can lead to sugar malabsorption in the intestine.

Animals↗
PubMed2000

Transactivation of EGF receptor induced by angiotensin II regulates fibronectin and TGF-beta gene expression via transcriptional and post-transcriptional mechanisms.

The signaling cascade elicited by angiotensin II (Ang II) resembles that characteristic of growth factor, and recent evidence indicates transactivation of epidermal growth factor receptor (EGF-R) by G protein-coupled receptors. Here, we report the involvement of EGF-R in Ang II-induced synthesis of fibronectin and TGF-beta in cardiac fibroblasts. Ang II stimulated fibronectin mRNA levels dose-dependently with a maximal increase (approximately 5-fold) observed after 12 h of incubation. Ang II-, or calcium ionophore-induced fibronectin synthesis was completely abolished by tyrosine kinase inhibitors and intracellular Ca2+ chelating agents. Ang II-induced fibronectin mRNA was not affected by PKC inhibitors or PKC depletion, whereas specific inhibition of EGF-R function by a dominant negative EGF-R mutant and tyrphostin AG1478 abolished induction of fibronectin mRNA. We isolated the rat fibronectin gene including the 5'-flanking region and found that the AP-1 binding site present in the promoter region was responsible for the Ang II responsiveness of this gene. Gel retardation assay revealed the binding of nuclear protein to the AP-1 site, which was supershifted with anti-c-fos and anti-c-jun but not anti-ATF-2 antibodies. Conditioned medium from Ang II-treated cells contained TGF-beta bioactivity and addition of neutralizing TGF-beta antibody modestly (46%) inhibited induction of fibronectin. Ang II-induced synthesis of TGF-beta was also abolished by inhibition of EGF-R function. The effect of TGF-beta was exerted by stabilizing fibronectin mRNA without affecting the promoter activity and required de novo protein synthesis. We concluded that Ang II-induced expression of fibronectin and TGF-beta is mediated by downstream signaling of EGF-R transactivated by Ca2+-dependent tyrosine kinase, and that Ang II-induced fibronectin mRNA expression is regulated by two different mechanisms; transcriptional control by binding of c-fos/c-jun complex to the AP-1 site, and post-transcriptional control by mRNA stabilization due to autocrine and/or paracrine effects of TGF-beta. Thus, this study suggested that the action of Ang II on extracellular matrix formation should be interpreted in association with the EGF-R signaling cascade.

Angiotensin II↗
PubMed2000

A hypothesis to explain the occurence of inner myometrial laceration causing massive postpartum hemorrhage.

BACKGROUND: Inner myometrial lacerations were found in three patients who developed uncontrollable postpartum massive bleeding despite the usual treatment for uterine atony. Because all the patients suffered from hemorrhage shock and their medical status deteriorated, their uteri were surgically removed to stop bleeding. After removal, one of them died. Postpartum hemorrhage was caused by inner myometrial laceration. We hypothesized a cause of inner myometrial laceration, using the three resected uteri, an assumed model of the uterine body, and 34 women. METHODS: The subjects were 37 women, of whom three were patients with inner myometrial laceration, 23 were women without inner myometrial laceration who underwent cesarean section, and 11 were women in the first stage of labor. The three resected uteri were examined both macroscopically and microscopically. We measured the thickness of the wall of the uterine muscle at the widest point of the uterine corpus and the thickness of the myometrial wall at a transverse section of the uterine cervix, as well as the radius of the inner lumen at the widest point of the uterus in 23 women during cesarean section. We also measured the thickness of the myometrial wall at the widest point of the uterine corpus in 11 women at the end of the first stage of labor during ultrasonic examination. The data were then used to estimate the stress on the uterine muscle. RESULTS: The stress on the uterine cervix was stronger than that on the uterine corpus during labor. When the stress on the uterine muscle is stronger than a specific value, inner myometrial lacerations develop on the right and/or left side of the uterine cervix. These lacerations may involve large vessels. CONCLUSIONS: We have discovered another cause of postpartum hemorrhage which we have named inner myometrial laceration. These lacerations appeared to result from a strong stress on the uterine cervix caused by an abnormal rise in intrauterine pressure during labor.

Abruptio Placentae↗
PubMed2000

Two cis-acting elements in the 3' untranslated region of alpha-CaMKII regulate its dendritic targeting.

Dendritic localization of the alpha subunit of Ca2+/calmodulin-dependent protein kinase II (alphaCaMKII) mRNA in CNS neurons requires its 3' untranslated region (3'UTR). We investigated this targeting mechanism by identifying two cis-acting elements in the 3'UTR. One is a 30-nucleotide element that mediated dendritic translocation. A homologous sequence in the 3'UTR of neurogranin, transcripts of which also reside in dendrites, also funtioned in cis to promote its dendritic transport. Other putative elements in the alphaCaMKII mRNA inhibit its transport in a resting state. This inhibition was removed in depolarized neurons, and such activity-dependent derepression was a primary requirement for their dendritic targeting.

Animals↗
PubMed2000

Expression of vascular endothelial growth factor by synovial fluid neutrophils in rheumatoid arthritis (RA).

Most of the leucocytes infiltrating rheumatoid synovial fluid (SF) are neutrophils capable of producing a variety of inflammatory mediators known to contribute significantly to the disease process during active RA. In the present study, we investigated the contribution made by SF neutrophils to the elevated levels of vascular endothelial growth factor (VEGF) seen in rheumatoid SF. Rheumatoid SF neutrophils were found to contain significantly larger amounts of both VEGF protein and its mRNA than peripheral blood neutrophils from either RA patients or healthy controls. Levels of cell-associated VEGF were well correlated with free VEGF in SF, which was significantly higher than in SF from osteoarthritis patients. Levels of SF neutrophil-associated VEGF also correlated with RA disease activity and cell surface integrin expression. Thus, SF neutrophil-associated VEGF may be considered an indicator of both local and systemic inflammation of RA, contributing to the neovascularization seen during RA synovitis.

Arthritis, Rheumatoid↗
PubMed2000

Optically clear nuclei in papillary carcinoma of the thyroid: demonstration of one of the fixation artifacts and its practical usefulness.

To examine whether or not optically clear nuclei are one of the fixation artifacts in papillary carcinoma of the thyroid. Experiments using an optimal immersion fixation method by making thin-sliced specimens, 5 x 2 x 2 mm in size were adopted. Fixatives tested were 10% formalin, 10% buffered formalin, mixture of alcohol and formalin (4: 1), 95% alcohol, 4% phosphate-buffered paraformaldehyde, Carnoy's fixative, Bouin's fixative and various concentrations of formalin. Tested thyroid lesions in total were: cases with papillary carcinoma (38); follicular carcinoma (one); follicular adenoma (15); adenomatous goiter (11); Hashimoto's thyroiditis (two); Grave's disease (five); and normal thyroid tissue around tumor (five). Routinely processed papillary carcinoma showed a high occurrence (64.6%) of the optically clear nuclei contrasted by a low occurrence (almost 0%) in other lesions. However, this rate in papillary carcinoma decreased (< 35.3%) in all experimental groups irrespective of the choice of fixatives. Frequent occurrence (61.9-66.6%) of the optically clear nuclei was reproduced in papillary carcinoma fixed in a higher concentration of formalin (40-60%) in the experimental groups. These results demonstrated that the optically clear nuclei are one of the fixation artifacts, although still useful as a diagnostic criterion.

Adenocarcinoma, Follicular↗
PubMed2000

Direct computation of multiple 3D flow convergence isovelocity surfaces from digital 3D reconstruction of colour Doppler data of the flow convergence region: an in vitro study with differently shaped orifices.

AIMS: Evaluation of the accuracy of direct computation of multiple three-dimensional (3D) flow convergence (FC) isovelocities by using digital reconstruction of colour Doppler data of the flow convergence region. METHODS AND RESULTS: We used a conventional ultrasound system (ATL HDI 3000) connected to a computer workstation via Ethernet link. The digital 3D datasets were directly transferred to a Silicon Graphic Imaging Octane workstation for later measurement. We generated nine pulsatile flows (20-60 ml/beat), with peak flow rates (67-180 ml/s), through three orifices (circular, rectangular and triangular, S=0.24 cm(2)). The 3D reconstructions of FC surface areas from multi-threshold velocities, including aliasing velocities were analysed to quantify the peak flow rate. For all orifices, linear regression demonstrated excellent correlation between the 3D calculated and electromagnetic flow meter recorded data. While there was a high correlation for 3D computation of flow rate from the single best Nyquist of 24 cm/s (r=0.97-0.98, SEE=7 .75-12.58 ml/s), the ability to average three threshold velocities (15, 18 and 24 cm/s) yielded an improved correlation (r=0.98-0.99, SEE=5.70-7.73 ml/s). CONCLUSIONS: Direct computation of multiple 3D FC isovelocities from digital reconstruction of colour Doppler data of the FC region provides the potential to accurately quantify the complex asymmetric spatial flow events at any selected velocity.

Blood Flow Velocity↗
PubMed2000

Experimental study of reconstruction of the temporomandibular joint using a bone transport technique.

PURPOSE: This study investigated the applicability of transport distraction osteogenesis with an internal appliance for reconstruction of the temporomandibular joint (TMJ). MATERIALS AND METHODS: Fifteen millimeters of the ascending ramus, including the condyle and intra-articular disc, was extirpated in 42 white rabbits (3.0 kg weight). After an L-osteotomy was performed from the anterior border of the coronoid process to the posterior border of the mandible, an internal distraction appliance was applied. The transport segment was advanced 0.9 mm/day for 14 days after a 14-day healing period. During a 24-week period after the completion of the lengthening, the rabbits were killed at various intervals. RESULTS: Eight weeks after the completion of the lengthening, the distraction gap between the transport segment and the preexisting mandible was indistinguishable in the radiographs. New bone and a large amount of cartilage were observed microscopically in the distraction gap. New bone was also observed at the leading edge of the transport segment. This bone seemed to form from the surrounding periosteum. At 8 weeks after the completion of lengthening, the mature cortical bone was reconstructed. A collagenous-like structure formed a cap over the leading edge of the transport segment. This cap may substitute for an articular disc. The new bone remodeled and resembled the condyle. CONCLUSION: The bone transport technique is promising for the reconstruction of TMJ.

Analysis of Variance↗
PubMed2000

Stability of simultaneous maxillary and mandibular osteotomy for treatment of class III malocclusion: an analysis of three-dimensional cephalograms.

PURPOSE: The current investigation was undertaken to study the three-dimensional (3-D) stability of simultaneous maxillary advancement and mandibular setback using rigid fixation. The study also aimed to analyse the factors involved in postsurgical relapse by evaluation of changes in various parameters. PATIENTS: Twenty-five cases were evaluated of simultaneous Le Fort I maxillary advancement and mandibular setback using rigid fixation. METHODS: Preoperative, immediate and 6-month postoperative skeletal and dental changes were analysed using 3-D cephalograms obtained from biplanar stereoradiography. Maxillary fixation screws were used as landmarks to evaluate postoperative stability. RESULTS: The mean maxillary advancement was 3.7 mm. Relapse in the sagittal, vertical, and transverse planes was not detectable in the maxilla (p > 0.05). However, for an average mandibular setback of 5.7 mm, mean mandibular relapse was 1.1 mm or 19.3% anteriorly (p < 0.05). Surgical or postsurgical skeletal changes in the maxilla had no detectable influence on mandibular relapse (p > 0.05). Vertical alterations of the facial skeleton achieved surgically predicted the mandibular relapse (R2 = 0.27, p < 0.05). CONCLUSION: Maxillary advancement and vertical changes of +/- 2 mm did not influence the postoperative stability of the mandible. Relapse of the mandible seems to be influenced mainly by the amount and direction of the surgical alteration of mandibular position.

Adult↗
PubMed2000

Seizure control after radiosurgery on cerebral arteriovenous malformations.

Among 462 cases of cerebral arteriovenous malformation (AVM) treated with gamma-radiosurgery, the initial presentations were haemorrhage in 68%, epilepsy in 12.8%, neurological deficits in 3.2%, minor symptoms in 7.6% and asymptomatic in 4.5% respectively. There were 79 cases (17.1%) who had had a convulsive seizure before radiosurgery and they were classified into two groups: 58 cases presented with seizure as an initial symptoms (group A) and the other 21 cases mostly had seizures following intracranial haemorrhage (group B). Before radiosurgery, generalised seizure was the predominant seizure pattern in both groups, followed by pure partial and complex partial seizures. There was no major difference in seizure patterns or seizure frequency in group A and B. At radiosurgery AVMs were treated with a mean maximum dose of 37.2 Gy and a marginal dose of 19.8 Gy. Seizures had apparently decreased in most of the cases at the last follow-up (mean 24 months) according to the obliteration of the nidus. Seizures were either decreased or had disappeared in 91.6% of group A and 62.5% of group B patients. The overall results indicate that seizures improved in 85.5%, were changed in 11.6% and deteriorated in 2.9% of patients. Radiosurgery is effective not only for the obliteration of nidus of cerebral AVM, but also for seizure control, even before complete occlusion of the nidus.

Adult↗