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Biomedical subjects

M Isono

Publications and source records attributed to M Isono.

At least 55 records · Page 3Linked to original sources
PubMed1997

Treatment of brain abscess associated with ventricular rupture--three case reports.

Three patients presented with brain abscess associated with ventricular rupture. The origins of infection were sepsis, congenital heart disease, and unknown, and the organisms were Gram-negative cocci in one and Streptococcus species in two. Ventricular rupture occurred before administration of antibiotics and caused consciousness disturbance in all three patients. Continuous ventricle drainage was begun and antibiotics were directly administered into the ventricles. Aspiration and drainage from the abscess was also performed in two patients. Ventricular irrigation resulted in an excellent effect in one patient. The outcomes were excellent in two patients and fair in one. Aggressive ventricular drainage in the very early stage and direct intraventricular administration of antibiotics are very important to obtain a favorable outcome in patients with brain abscess and ventricular rupture.

Adult↗
PubMed1997

Mitogen-activated protein kinase cascade is activated in glomeruli of diabetic rats and glomerular mesangial cells cultured under high glucose conditions.

The activation of protein kinase C (PKC) found in diabetic glomeruli and glomerular mesangial cells cultured under high glucose conditions has been proposed to contribute to the development of diabetic nephropathy. However, the abnormalities distal to PKC have not been fully elucidated yet. Herein, we provide the evidence that mitogen-activated protein kinase (MAPK) cascade, an important kinase cascade downstream to PKC and an activator of cytosolic phospholipase A2 (cPLA2) by direct phosphorylation, is activated in glomeruli isolated from streptozotocin-induced diabetic rats. MAPK cascade was also activated in glomerular mesangial cells cultured under high glucose (27.8 mmol/l) conditions for 5 days, and the activation of MAPK cascade was inhibited by treating the cells with calphostin C, an inhibitor of PKC. Furthermore, the activities of cPLA2 also increased in cells cultured under the same conditions and this activation was inhibited by both calphostin C and PD 098059, an inhibitor of MEK (MAPK or extracellular signal-regulated kinase [ERK] kinase). These results indicate that MAPK cascade is activated in glomeruli and mesangial cells under the diabetic state possibly through the activation of PKC. Activated MAPK, in turn, may induce various functional changes of mesangial cells at least through the activation of cPLA2 and contribute to the development of diabetic nephropathy.

Animals↗
PubMed1997

[Morphological characterization and classification of air cells in temporal bone by digital processing of CT images].

We determined the extent of pneumatization in the temporal bone and reconstructed three-dimensional structures of air cells by computer-assisted digital processing of high resolution CT images of the bone. We attempted morphological classification of temporal bone air cells by characterization of the three-dimensional structures obtained. A total of 52 ears in 33 normal subjects (18 males and 15 females; mean age 51 years) was examined. The volume of pneumatization in the temporal bone, as measured by CT, ranged from 2.08 to 20.05 ml (mean 6.40 +/- 4.09). The morphological characteristics of air cells in the three-dimensional images were examined with reference to the volume of air cells and the direct on of their growth. The three-dimensional structures were observed from four directions (lateral, supralateral, anterolateral and supramedial). Large air cells existed plentifully in all directions. Anteriorly, air cells were growing in two directions; laterally and toward the petrous apex. The growth in the latter direction was especially marked, and this contributed to the growth in the medial direction. Air cells that grew anteriorly had two directions of growth (lateral and toward the petrous apex). The directional difference in growth varied with the ear. On examining the suprainferior growth, air cells that grew large in the anterior direction were found to grow large in the suprainferior direction and those that did not grow large in the anterior direction were found contrarily to grow poorly in the suprainferior direction. With the above morphological characteristics taken into consideration, morphological classification of air cells into five types was attempted by the volume of air cells and the direction of their growth.

Adolescent↗
PubMed1997

[CT-assisted measurement of total and regional volumes of pneumatization in the temporal bone].

The total volume of air cells in the temporal bone and the regional volumes (tympanic cavity, petrous apex and mastoid antrum) were measured by using a system which we developed for the measurement of air cells by computerized digital processing of high-resolution CT images. We examined a total of 41 normal ears in 25 subjects ranging in age from 12 to 82 years (mean age 46.2). The total volume of pneumatization was approximately 4.05 +/- 1.59 ml and the volume of air cells in the tympanic cavity was 0.45 +/- 0.07 ml. Alveolation of the petrous apex was detected in 15 (36.6%) of the 41 ears, and the volume of air cells in the petrous apex was approximately 0.24 +/- 0.26 ml. The volume of air cells in the mastoid antrum was approximately 0.53 +/- 0.20 ml. The ears were divided into two groups, one with petrous alveolation (15 ears) and the other without it (26 ears). The ratios of regional pneumatization to total pneumatization were studied in the two groups. Statistically significant differences were found in the total volume and the volume of air cells in the mastoid antrum between the groups with and without petrous pneumatization (p < 0.05). The total volume of air cells did not correlate to the volumes of air cells in the tympanic cavity, mastoid cavity and petrous apex.

Adolescent↗
PubMed1997

[Neovascularization after encephalo-duro-arterio-synangiosis in elderly quasi-moyamoya disease: a case report].

A 65-year-old man who had a history of diabetes mellitus visited a hospital for recent memory disturbance. MR angiography showed stenoses of the main trunks of the intracranial arteries. He was admitted to our hospital, and angiography revealed occlusion of the left cervical internal carotid and right middle cerebral arteries, and stenoses of the right internal carotid, right anterior cerebral, left vertebral, and right posterior cerebral arteries. There was collateral circulation formed from the left external carotid and left posterior cerebral arteries. Basal moyamoya vessels were also observed. 123I-IMP SPECT showed low perfusion of the right cerebral hemisphere, and response to acetazolamide was poor. Based on the angiographical findings and the presence of diabetes mellitus, the patient was diagnosed as having quasi-moyamoya disease. Vascular reconstructive surgery was indicated. Since there was no recipient artery adequate for STA-MCA anastomosis, encephalo-duro-arterio-synangiosis was performed on the right side. Postoperatively, the patient's recent memory improved gradually, and angiography performed 7 months after the operation revealed neovascularization from the superficial and deep temporal arteries. Although indirect bypass surgery has been applied mainly to child moyamoya disease, its effectiveness for cerebral ischemia in adult patients has also been reported, particularly in cases with misery perfusion. Neovascularization with indirect bypass surgery can be expected if the patient is under misery perfusion, even in elderly patients.

Aged↗
PubMed1997

Mechanism of the progression of diabetic nephropathy to renal failure.

Although the evolution of diabetic nephropathy is brought about mostly by persistent hyperglycemia, its progression may be influenced by various other factors such as hypertension and dietary protein intake. It has been recently suggested in the literature that the gene polymorphism of angiotensin converting enzyme (ACE) might be associated with the development of diabetic nephropathy, because the DD genotype of ACE gene is closely associated with the presence of nephropathy in diabetic subjects. However, in our present analysis the frequency of the DD genotype in patients with non-insulin dependent diabetes is not significantly related to the presence or absence of nephropathy. It remains to be clarified by multi-center analysis using large numbers of patients whether the gene polymorphism of ACE is related to the progression of diabetic nephropathy to renal failure. Furthermore, it has been postulated that the interstitial fibrosis evaluated in renal biopsy specimens is significantly correlated with the declining of renal function in diabetic patients. However, it is not possible to clinically quantitate the interstitial fibrosis without performing renal biopsy. We have recently found that the urinary excretion of type IV collagen is significantly increased in diabetic patients. Moreover, the increase in urinary type IV collagen is well correlated with the amount of urinary albumin. Since type IV collagen in the urine is probably derived from tubulointerstitial tissue, it is likely that the increased amount of type IV collagen in the urine may reflect the fibrotic change in diabetic kidneys. Whether the increase in urinary type IV collagen is able to predict for the progression of diabetic nephropathy in the future should be examined.

Collagen↗
PubMed1996

Atrial natriuretic peptide induces the expression of MKP-1, a mitogen-activated protein kinase phosphatase, in glomerular mesangial cells.

Atrial natriuretic peptide (ANP) has been shown to inhibit the proliferation of various types of cells including glomerular mesangial cells. The activation of mitogen-activated protein kinase (MAPK) is one of the main signal transduction systems leading to cell proliferation. MAPK is tightly regulated by the activating kinase, MEK, and specific phosphatase MKP-1. Constitutive expression of MKP-1 has been shown to inhibit cell proliferation by suppressing MAPK activity. In order to understand the mechanism of the anti-proliferative effect of ANP, we examined whether ANP could inhibit MAPK by inducing MKP-1 in cultured rat glomerular mesangial cells. ANP increased the expression of MKP-1 mRNA in a dose-dependent (10 nM maximum) and time-dependent, with a peak stimulation at 30 min, manner. Receptor for ANP is a transmembrane guanylyl cyclase. Activation of guanylyl cyclase of ANP receptor by ligand plays an essential role in ANP signal transduction. 8-Bromo-cGMP, a cell permeable analogue of cyclic GMP, and sodium nitroprusside, an activator of soluble guanylyl cyclase, could mimic the effects of ANP and were able to induce the expression of MKP-1 in a similar time course as ANP. The protein expression of MKP-1 was maximally stimulated by ANP at 120 min. Treatment of the cells with ANP for 120 min resulted in an inhibition of phorbol ester-induced activation of MAPK, while the activation of MEK was not affected by ANP. These results indicate that ANP might inhibit the proliferation of mesangial cells by inactivating MAPK through the induction of MKP-1.

Amino Acid Sequence↗
PubMed1996

Bcl-2 expression is correlated with a low apoptotic index and associated with progesterone receptor immunoreactivity in endometrial carcinomas.

A total of 103 endometrial carcinomas (endometrioid type), as well as 15 samples of normal (atrophic or proliferative phase) and 26 of hyperplastic endometrium, were immunohistochemically investigated for expression of Bcl-2, and oestrogen and progesterone receptors (ER and PR), and the results compared with findings for apoptosis and cell proliferation. Carcinoma cases were subdivided into tubular and solid components on the basis of tumour growth patterns. Immunopositivity for Bcl-2, ER, and PR in tubular components was significantly higher than in the solid category, being negatively associated with histological grading. Immunoreactivity scores revealed that Bcl-2 in the tubular group was positively correlated with PR but not ER, while its expression in normal and hyperplastic endometrium was closely linked with both. Apoptotic and mitotic indices (AI and MI) were both significantly lower in tubular than in solid areas. In the tubular areas, AI, values were significantly lower in the subgroup with a high level of Bcl-2 expression than in either low-level or negative groups. These results indicate that Bcl-2 expression may play a central role in the inhibition of apoptosis in endometrial carcinoma, in particular those cases with tubular components, possibly being associated with PR rather than ER. Changes in the propensity for apoptosis may be related to alterations of tumour growth pattern and of features of differentiation.

Apoptosis↗
PubMed1996

Corticospinal direct response to transcranial magnetic stimulation in humans.

The corticospinal motor evoked potential (MEP) response to transcranial magnetic stimulation of the motor cortex was investigated in comparison with the direct (D) response to electrical stimulation of the exposed motor cortex from the spinal epidural space in 7 neurologically normal patients during brain tumor surgery. The D response during operation was obtained by transcranial magnetic stimulation of the scalp over the areas of the cerebral motor cortex, the hand or arm areas. The magnetic induced D response showed a conduction velocity of 50.5-72.7 m/sec and was resistant to anesthesia and unaffected by muscle relaxants and tolerant to high frequency (500 Hz) paired magnetic stimulus, and the latencies of magnetic MEPs corresponded to those with direct electrical stimulation. Thus, recordings of the D response by transcranial magnetic stimulation are useful for not only identifying the location of the motor cortex during intracranial surgery but also for non-invasive recording of pyramidal tract activity during extracranial surgery under general anesthesia.

Aged↗
PubMed1996

An objective evaluation method for facial mimic motion.

This technique was designed to establish a simple, objective evaluation system for facial paralysis through the use of a personal computer. A total of 24 marks were placed on the faces of subjects for the following procedures. Movements of the face were photographed with a video-camera and fed continuously into the computer. Ten frames per movement representing facial movement from rest to maximum movement were selected for analysis. By means of a digital image-processing technique, only the marks placed on the face were extracted, and the movement of these marks was quantitatively analyzed. A total of 44 healthy subjects with no history of facial paralysis were used as a normal control group. The patients with facial paralysis consisted of nine subjects with Bell's palsy and three with Ramsay Hunt syndrome. In the eye-closing motions, no significant differences were found between the sum of the movement distances on the left and right sides in each normal subject. However, the patients with facial paralysis showed distinct differences from those obtained in the normal subjects. The improvement process was also evaluated with a ratio of affected- and normal-side facial movements.

Blinking↗
PubMed1996

[Comparison of measuring an area with a planimeter and by rectangular dimensional methods].

We have developed a system that measures the volume of air cells in the temporal bone through computerized digital processing of high-resolution CT images. By using this method, the volume of pneumatization was measured, and the results were compared with the measured area of pneumatization obtained from two conventionally used simple ear X-ray methods (the planimeter and rectangular dimensional methods). A total of 57 ears, from 34 subjects, confirmed as normal by CT were examined. The average volume of pneumatization measured on CT images was 5.97 +/- 4.15ml, and the average areas of pneumatization measured by the planimeter and rectangular methods were 9.08 +/- 5.64 and 17.39 +/- 9.77 cm2, respectively. Graphically, when the volume of pneumatization was plotted on the Y axis and the planimeter-measured area of pneumatization on the X axis, a regression formula of Y = 0.651X + 0.054 was obtained, with a correlation coefficient of 0.89. With the volume of pneumatization plotted on the Y axis and the rectangular-dimensional-measured area of pneumatization on the X axis, the regression formula was Y = 0.375X - 0.559, with a correlation coefficient of 0.88. Both these correlation coefficients were considered high. Furthermore, 3D models of the air cells in the temporal bone were created and compared for patients with high and low correlations. In order to capture the morphological characteristics of these 3D models, they were examined from four different angles (lateral, upper lateral, anterior lateral and upper medial). The results showed that regardless of whether air-cell growth was present in the direction of the apex partise petrosae in patients with a low correlation coefficient, such growth played a major role in the degree of the correlatiton. Future studies will be required to clarify this point, though it can already be said that 3D models are indispensable for studying the air cells in the temporal bone. When we compared the volume and area of pneumatization in the temporal bone at different CT cross-sections, we found correlation coefficients in the vicinity of the canalis semicircularis lateralis of about 0.9 or higher. A statistical comparison of correlation coefficients for the CT, planimeter, and rectangular dimensional methods, made by using the CT cross-section with the highest coefficient, found a significant difference between the CT method and the other two methods (p < 0.05). In other words, the volume of pneumatization can be estimated more accurately with CT images than with simple ear X-rays.

Adolescent↗
PubMed1995

The exogenous control of transfected c-fos gene expression and angiogenesis in cells implanted into the rat brain.

Previously, we established a stable transfectant, Nf-1, from normal rat kidney (NRK) fibroblasts transfected with a human metallothionein II A (hMT-IIA) promoter/human genomic c-fos fusion gene to produce c-Fos protein. Since the hMT-IIA promoter can be activated by heavy metals, the level of human c-fos gene expression can be increased by addition of heavy metals to the culture medium of Nf-1 cells and the anchorage-independent growth of Nf-1 in soft agar is markedly enhanced in the presence of transforming growth factor-beta (TGF-beta) and epidermal growth factor (EGF). In this study, we found that the hMT-IIA promoter can be activated by zinc, resulting in the elevation of fused c-fos gene expression in Nf-1 cells. We transplanted NRK and Nf-1 cells into the striatum of the rat brain and investigated whether expression of the human c-fos gene could be modified in the brain by exogenous zinc. After 8 weeks, we found that the Nf-1 cells could survive in the rat brain without any immunosuppression and grafts of Nf-1 induced angiogenesis when zinc was administered. Such implants enhanced the expression of c-fos mRNA by zinc. These results indicated that the transplanted cells continued expressing the c-fos transgene when the rats were given drinking water containing zinc, resulting in the promotion of cell growth and of neovascularization. This study will present a useful animal model of gene therapy by control of transgene expression in the brain.

Animals↗
PubMed1995

Dual pathways of tubular morphogenesis of vascular endothelial cells by human glioma cells: vascular endothelial growth factor/basic fibroblast growth factor and interleukin-8.

In this study, we examined whether human glioma cells are angiogenic in a model using human microvascular endothelial cells, and also which factor is responsible for the glioma-dependent angiogenesis. Tubular morphogenesis in type I collagen gel by human microvascular endothelial cells was stimulated in the presence of 10 and 100 ng/ml of vascular endothelial growth factor (VEGF), 10 ng/ml basic fibroblast growth factor (bFGF) and 10 ng/ml of interleukin-8 (IL-8). Tube formation of the microvascular endothelial cells was assayed in the glioma cell lines IN157 and IN301, co-cultured using the double chamber method. IN301 cells had much higher levels of VEGF, bFGF and transforming growth factor-beta mRNA than IN157 cells, whereas the two had similar levels of transforming growth factor-alpha mRNA. By contrast, IN157 cells had much higher levels of IL-8 mRNA than IN301 cells. IN301-dependent tubular morphogenesis was inhibited by anti-VEGF or anti-bFGF antibody, and the inhibition was almost complete when anti-VEGF and anti-bFGF antibodies were present. On the other hand, IN157-dependent tubular morphogenesis was inhibited by anti-IL-8 antibody, but not by anti-VEGF or anti-bFGF antibodies. These findings demonstrated dual paracrine controls of tumor angiogenesis by human glioma cells. One is mediated through VEGF and/or bFGF, and the other, through IL-8.

Astrocytoma↗
PubMed1995

Effect of spinal cord stimulation on cerebral blood flow in cats.

Effects of electric spinal cord stimulation (SCS) on cerebral blood flow (CBF) were investigated in anesthetized adult cats. SCS was performed under various stimulus conditions for 1 h via a wire electrode inserted into the dorsal epidural space at various levels in the spinal cord. CBF was measured in the subcortex of the parietal lobe by hydrogen clearance method before, during, and after SCS. After the start of SCS in the high cervical cord with a frequency of 20 Hz, CBF gradually increased up to 140% of the pre-SCS value, and remained high for 15 min after the end of SCS. SCS of the low cervical or midthoracic cord under the same condition caused no significant increase in CBF. Nor did SCS of the high cervical cord with frequencies of 200 and 2,000 Hz increase CBF. No CBF increase was observed after SCS of the high cervical cord with 20 Hz when the dorsal column was sectioned at the medullo-cervical junction. These results suggest that the ability of SCS to increase CBF is peculiar to high cervical cord stimulation with moderately low frequencies.

Analysis of Variance↗
PubMed1994

Involvement of a DNA binding protein, MDR-NF1/YB-1, in human MDR1 gene expression by actinomycin D.

The human multidrug resistance 1 (MDR1) gene is an SOS gene that responds to environmental stress including various anticancer agents. The chloramphenicol acetyltransferase (CAT) gene was linked to various lengths of MDR1 promoter, and these constructs were integrated into the genome of human cancer KB cells. Using these cell lines, we previously demonstrated that various environmental stimuli lead to an increased abundance of both CAT enzymatic activity and CAT mRNA in a sequence dependent manner. We examined the molecular mechanism of this stress response using actinomycin D, a potent RNA synthesis inhibitor. We found that CAT activity was significantly increased more than 10 fold by actinomycin D itself without comparable elevation of CAT mRNA. CAT induction was, however, lost in the presence of a deletion from position -136 to -76. Gel mobility shift assays showed that the specific DNA binding activity of the transacting protein, MDR-NF1/YB-1, which binds to the inverted CCAAT box, was augmented in nuclear extracts from the cells treated with actinomycin D. We also found that actinomycin D increased the steady state levels of MDR-NF1/YB-1 mRNA, which encodes the inverted CCAAT box binding protein. These results indicate that MDR-NF1/YB-1 mediates the response of the MDR1 gene to environmental stress.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

[Assessment of the volume of the mastoid air cell system using digital image processing].

There has been a great deal of controversy concerning the development of pneumatization in the temporal bone. Many reports on the size of the mastoid air cell system have been discussed a planimetric X-ray method, however, there have been no techniques for direct volume measurement based on high-resolution computed tomography (CT). Discussion of the relationship between ear disease and pneumatization of the temporal bone requires three-dimensional measurement of the temporal bone in vivo. Recently, we developed such a technique by using digital image processing to measure the volume of the mastoid air cell system. With this technique, only the air cells and tympanic cavity, with a grey scale level similar to air outside the skull were easily selected on the CT films. Then, after image processing called "thresholding", only the areas and volumes of these extracted pneumatized parts were calculated. The volumes of the pneumatized parts of the temporal bone were calculated separately as partial volumes divided by several CT planes. The sum of the partial volumes was calculated as the total volume of the aerated cavity. This technique also made it possible to reconstruct a three-dimensional (3D) model of the air cell system for visual presentation. CT images of 43 normal temporal bones were analyzed. The average volume temporal bone pneumatization (including air cells and tympanic cavity) was about 6ml. There were no differences between pneumatization on the two sides in either sex. Comparisons of partial volumes of pneumatization in the temporal bone revealed that the volumes of portions including the tympanic cavity and its surrounding air cells and those of the antrum and its surrounding air cells were larger than those of other portions. 3D models of the air cell system revealed a variety of shapes. These findings indicated that this technique is not only useful for quantitative analyses but for easy subjective morphological analyses.

Adult↗
PubMed1994

[Computerized analysis of facial motions--objective evaluation of facial palsy].

The severity of facial palsy is often diagnosed using a scoring system. However, there have been some problems as to the objectivity and reproducibility of evaluations by this method. To solve these problems, a variety of new methods have been introduced. Compared to the simple scoring method, none of these methods seem to have gained wide-spread application in routine clinical practice. The development of our diagnostic system was inspired by the idea that numerical quantitation of shifting of marks on the face might be possible by means of digital image-processing. Using this method, only marks adhering to the face are extracted, and the shifting position of these marks is quantitatively analyzed. Detailed analysis of the facial movement requires full motion video images. We found that such video images were easily obtainable by application of a Quick Time Movie developed by Apple computer. Twelve healthy subjects served as normal controls. Seven patients were analysed as cases of facial palsy. The facial movements examined in this study consisted of eye-closing and whistling. A total of 20 black marks were used for adherence to the face. The image processing called thresholding leaves only black marks on the face and has made it possible to trace and measure these marks on the face. The shifting positions of the marks moving in accordance with facial movement, from the stationary phase until the maximum stage, were measured and traces were plotted on the coordinate axis. The shifting of the marks adhering to the face was numerically expressed as a trajectory investigation.(ABSTRACT TRUNCATED AT 250 WORDS)

Facial Muscles↗