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Biomedical subjects

Y Matsui

Publications and source records attributed to Y Matsui.

At least 253 records · Page 14Linked to original sources
PubMed1995

Spinal cord protection during thoracoabdominal aortic aneurysm repair: results of selective reconstruction of the critical segmental arteries guided by evoked spinal cord potential monitoring.

PURPOSE: The purpose of this study is to evaluate the results of spinal cord protection based on selective reconstruction of the segmental arteries. METHODS: Twenty-one patients who underwent repair of aneurysms (nine descending thoracic and 12 thoracoabdominal: three type I, six type II, and three type III) were analyzed. Ten patients had postdissection aneurysms. Operative techniques consisted of evoked spinal cord potential (ESP-dsc) monitoring and femorofemoral bypass in all cases, segmental resection in 12, and mild systemic hypothermia in eight. Arteries critical for cord blood flow were selectively reconstructed; if ESP-dsc showed change after resection of an aortic segment, arteries originating from this segment were reconstructed. RESULTS: ESP-dsc change was observed in 12 patients. Arteries found to be critical were at the T8-L1 level in all but three cases. Selective reconstruction was performed in 10 of these 12 patients. ESP-dsc change could be reversed before reconstruction in four cases, three by control of back-bleeding critical arteries. Selective reconstruction resulted in return of ESP-dsc in seven other patients. Spinal cord injury occurred in five patients, two of whom did not undergo selective reconstruction. CONCLUSION: These results suggest that our current technique allows determination of critical arteries but does not completely prevent injury.

Adult↗
PubMed1995

Speech function following maxillectomy reconstructed by rectus abdominis myocutaneous flap.

Post-surgical maxillary defects have recently been reconstructed by microvascularized free flaps. However, few reports have evaluated the resulting speech function. This study compared the speech intelligibility of four maxillectomy patients who underwent reconstruction by rectus abdominis myocutaneous flaps (RAMCF) with that of four non-reconstructed patients who were treated with split-skin grafts and prostheses, to explore ways of achieving better speech function. Speech function was assessed by a Japanese language speech intelligibility test. Intelligibility scores ranged from 57.3% to 75.8% (mean, 70.4%) in the non-reconstructed group and from 66.2% to 77.2% (mean, 71.0%) in the reconstructed group. An analysis of articulatory manners and sites revealed that speech disorders resulted mainly from poor oronasal separation in the non-reconstructed group and from incorrect linguopalatal contact in the reconstructed group, especially for linguodentoalveolar and linguovelar sounds. Therefore, for higher speech function in the reconstructed group, dentoalveolar and palatal contours of the maxilla must be restored as closely as possible. This must also be done in patients whose maxillae are reconstructed by other types of microvascularized myocutaneous or cutaneous flaps that have similar postoperative palatal contours.

Adult↗
PubMed1995

Effect of age and radiation on bone healing adjacent to hydroxyapatite placed in the tibia of rats.

This study investigated the effect of age and radiation on healing after implantation of hydroxyapatite granule in bone. Two groups of 16 male Wistar rats, aged 4 weeks and 2 years were used for this study. Hydroxyapatite particles were placed into the tibia 28 days after the delivery of 15 Gy of irradiation from a Linac source. The results of the present study suggest that an old rat was more vulnerable to the radiation than a young rat. It seemed that age might also be an important factor in the prognosis of the implanted hydroxyapatite in irradiated bone.

Age Factors↗
PubMed1995

A case of paroxysmal tonic upward gaze associated with psychomotor retardation.

The authors report a female with paroxysmal tonic upward gaze similar to the cases reported by Ouvrier and Billson (1988). She developed abnormal eye-movements at the age of six months. Several anticonvulsants and levodopa were not effective in the control of the episodes; however, her upward eye-deviations spontaneously decreased during the one-year observation. Her clinical features were almost identical to those reported by Ouvrier and Billson, except that she had neurodevelopmental disorder and abnormal brain MRI. More data are required to clarify this unique phenomenon.

Anticonvulsants↗
PubMed1995

[A clinical study of six cases of toxic shock-like syndrome by group A Streptococcus].

We have encountered six cases with toxic shock-like syndrome (TSLS) by Group A Streptococcus since 1978. Every patient had from the onset flu-like symptoms or high fever and immediately developed some of the following clinical signs: hypotension, acute renal failure, disseminated intravascular coagulation (DIC), and adult respiratory distress syndrome (ARDS). Three of the six patients died with rapid clinical courses and three survived. As for the surviving patients, early administration of antibiotics and anti-DIC therapy were effective. Streptococcus pyogenes were isolated from the blood in five of the patients, ascites from another, and necrotizing tissue in one patient. The serovars of the isolated strains were typed as T1/M1 in three, T8 in one, and T28 in another. The toxin-type of the strains were typed as B in four and B + C in one. Though there have been few reports of TSLS before 1992 in Japan, it is supposed that many TSLS cases may have potentially occurred.

Aged↗
PubMed1995

Effect of atrial and ventricular activation interval on hemodynamics during atrioventricular and ventriculoatrial pacing: determination from pressure-volume loops in dogs.

To determine the effect of relative timing of atrial and ventricular activation on hemodynamic indices, we evaluated pressure-volume loops during pacing at 160 beats/min with various atrioventricular intervals in dogs. End-systolic pressure, end-diastolic volume, and stroke volume were reduced during pacing at atrioventricular intervals of 0 ms, compared with 80 ms. These changes were more significant during pacing at atrioventricular intervals of -50 and -100 ms than at 0 ms. During tachycardia, the abnormal timing of atrial contraction leads to unfavorable hemodynamic change and the degree of the changes are determined by the ventriculoatrial activation interval.

Animals↗
PubMed1995

Ultrastructural features of alveolitis in sarcoidosis.

Seventy-nine specimens of lung parenchyma from 61 patients with sarcoidosis were examined ultrastructurally with a focus on alveolitis, and they were compared with specimens of hypersensitivity pneumonitis (HP) and the percentage of lymphocytes in bronchoalveolar lavage fluid (BALF). Lymphocytes and monocytes were frequently observed in the capillary lumina, and these cells and macrophages were found in the interstitium of the alveolar walls in the specimens with alveolitis of sarcoidosis and HP. Increases in the percentage of lymphocytes in BALF correlated with the degree of alveolitis. Swelling and bleb formation of the endothelium of alveolar capillaries and changes in the capillary basement membrane were commonly found and were significantly increased in the specimens with alveolitis. The frequency of bleb formation was significantly higher in alveolitis of sarcoidosis than in that of HP. However, the changes in alveolar epithelium were not significant in sarcoidosis. Microvascular changes in alveolitis are not specific for sarcoidosis, but they are observed in other interstitial lung diseases. These alterations may play an important role in the development of pulmonary sarcoidosis.

Adult↗
PubMed1995

Bronchoalveolar mast cells in summer-type hypersensitivity pneumonitis: increase in numbers and ultrastructural evidence of degranulation.

To investigate the role of mast cells in the development of summer-type hypersensitivity pneumonitis (SHP), which is the most common type of hypersensitivity pneumonitis in Japan, bronchoalveolar lavage fluid (BALF) cells from 13 patients with this disease was studied by light and electron microscopy. The proportion and number of BALF mast cells recovered from SHP patients were significantly greater than those from patients with sarcoidosis and from control subjects. The BALF mast cells from the SHP patients showed various ultrastructural changes such as the transformation of granules, cytoplasmic vacuolation, and an increase of lipid droplets. These findings appeared to reflect activation and degranulation of bronchoalveolar mast cells, suggesting that mast cells play a role as inflammatory cells in the development of SHP.

Adult↗
PubMed1994

Cerebellar infarctions secondary to cranio-cervical anomalies: a case report.

We report a case of cerebellar infarctions which occurred in the territories of the bilateral posterior inferior cerebellar arteries. This case was complicated with cranio-cervical anomalies composed of assimilation of the atlas, atlanto-axial dislocation, and basilar impression. The 40-year-old male patient had no detectable risk factors predisposing to atherosclerotic arterial occlusion or cardiogenic embolism, and there were no angiographic findings of atherosclerosis. It was, therefore, postulated that the cerebellar infarctions were secondary to those cranio-cervical anomalies. The developing mechanism is discussed.

Adult↗
PubMed1994

Acceleration of mammary neoplasia in transforming growth factor alpha transgenic mice by 7,12-dimethylbenzanthracene.

A mouse mammary tumor virus enhancer/promoter-transforming growth factor alpha transgenic mouse model has been described in which mammary tumors develop (Y. Matsui et al., Cell, 61: 1147-1155, 1990). In Line 29, spontaneous mammary tumors do not develop before 300 days of age in virgin females. Herein, Line 29 virgin females and their nontransgenic littermates have been treated with 7,12-dimethylbenzanthracene (DMBA) at varying dosages and times. Orogastric instillation of a single dose of DMBA (0.5 mg) dramatically accelerates mammary tumor formation when administered to 21- and 56-day-old virgin transgenic females compared to their nontransgenic littermates. The latency period for tumor formation is significantly shorter in transgenic mice treated with DMBA at 56 days compared to transgenic mice treated with DMBA at 21 days when results are analyzed by time from DMBA administration. To determine whether differences in the proliferative state of the mammary gland may contribute to these findings, bromodeoxyuridine incorporation was examined in the mammary glands of untreated 21- and 56-day-old mice. No differences in bromodeoxyuridine incorporation were detected between 21-day-old transgenic and nontransgenic mice. However, there was a marked increase in bromodeoxyuridine incorporation in the epithelial cells comprising the smaller ducts of 56-day-old transgenic mice compared to their nontransgenic littermates. These data indicate an enhancing interaction between a growth factor and a genotoxic carcinogen in mammary tumorigenesis and provide evidence that the transforming growth factor alpha transgene acts as a tumor promoter in this experimental model.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1994

Isolation of a CDC25 family gene, MSI2/LTE1, as a multicopy suppressor of ira1.

We have identified MSI2 as a gene of Saccharomyces cerevisiae which, when on a multicopy vector, suppresses the heat shock sensitivity caused by the loss of the IRA1 product, a negative regulator of the RAS protein. The multicopy MSI2 also suppresses the heat shock sensitivity of cells with the RAS2val19 mutation but not those with the bcy1 mutation, suggesting that the MSI2 protein may interfere with the activity of the RAS protein. The sequence analysis of MSI2 reveals that it is identical to LTE1 belonging to the CDC25 family: CDC25, SCD25 and BUD5, each of which encodes a guanine nucleotide exchange factor for the ras superfamily gene products. Deletion of the entire MSI2 coding region reveals that MSI2 is not essential but the disruptant shows a cold-sensitive phenotype. Under the non-permissive conditions, more than 70% of the msi2 disruptants arrested at telophase as large budded cells with two nuclei divided completely and elongated spindles, indicating that the msi2 deletion is a cell division cycle mutation. These results suggest that MSI2 is involved in the termination of M phase and that this process is regulated by a ras superfamily gene product.

Amino Acid Sequence↗
PubMed1994

Prognostic value of initial electroretinogram in central retinal vein obstruction.

We retrospectively studied the correlation between the initial electroretinogram (ERG) recordings and the final visual acuities (VA) of 47 patients with central retinal vein obstruction (CRVO) after follow-up of more than 1 year. The a- and b-wave amplitudes and the b/a ratio with white flash were significantly larger in patients with good vision (VA > 20/200) than in those with poor vision (VA < or = 20/200). The b/a ratio and b-wave amplitude with white flash showed sensitivity and specificity of more than 78% for visual prognosis. The latest VA was < or = 20/200 in all 20 patients with a subnormal b-wave amplitude and in all 15 with b/a ratio < 1.05. These results suggest that the ERG recorded soon after (CRVO) onset correlates strongly with visual prognosis.

Adult↗
PubMed1994

Correlation of electroretinographic and fluorescein angiographic findings in unilateral central retinal vein obstruction.

BACKGROUND: In central retinal vein obstruction (CRVO), electroretinogram (ERG) abnormalities and extensive retinal capillary dropout (CD) in the fluorescein angiogram (FA) are good indicators of retinal ischemia. We retrospectively studied patients with unilateral CRVO and compared the ERG and FA results. METHODS: Single white flash ERG, photopic ERG, scotopic ERG and flicker ERG were recorded in 30 cases of unilateral CRVO. We analyzed the correlation between the ERG results and the presence/absence of extensive CD. RESULTS: The ERG b/a-wave amplitude ratios, photopic and scotopic b-wave amplitudes, and flicker amplitudes were significantly smaller (P < 0.05) in eyes with extensive CD (n = 12, 40%), than in eyes without (n = 18, 60%). When the photopic or scotopic b-wave amplitudes were normal or supernormal, extensive CD on FA was absent in all eyes. When the b/a-wave ratios were > or = 1.0 or when the b-wave amplitudes with white flash or flicker amplitudes were normal or supernormal, extensive CD was present in less than 32% of eyes. CONCLUSION: These results suggest that the ERG results, especially the b/a-wave amplitude ratio, are significantly correlated with the presence/absence of CD on FA in CRVO.

Adult↗
PubMed1994

Influence of simultaneous pattern-reversal electroretinogram recording on visual evoked potentials.

Little is known about the influence of the presence of a gold-foil electrode on pattern-reversal visual evoked potential recording, although simultaneous pattern-reversal electroretinography has been applied in several clinical investigations. We compared the results of pattern-reversal visual evoked potentials simultaneously recorded with pattern-reversal electroretinograms with those obtained during separate pattern-reversal visual evoked potential recording in 10 normal subjects. Transient response (reversal rate, 1 Hz; check size, 30') and steady-state response (reversal rate, 5 Hz; check size, 120', 60', 30', 15' and 7.5') were analyzed under the stimulus contrast condition of 90%. Neither P100 latency in transient responses nor amplitudes in steady-state responses exhibited significant change at any check size when they were recorded separately or simultaneously with pattern-reversal electroretinograms. The results suggest that the gold-foil electrode exerts no significant influence on pattern-reversal visual evoked potentials. Simultaneous pattern-reversal electroretinogram and visual evoked potential recording is therefore confirmed to be a clinically useful method. This procedure makes the synchronous recording of both responses possible under the identical stimulus conditions.

Adult↗
PubMed1994

Adenylate energy charge of rat and human cultured hepatocytes.

A simple and rapid method for the assay of adenine nucleotides (ATP, ADP, and AMP) was established to evaluate the adenylate energy charge (ATP+ADP/2)/(ATP+ADP+AMP) of cultured hepatocytes. The effects of inhibitors of glycolysis, fatty acid oxidation, or oxidative phosphorylation on the energy charge were examined. The energy charges of cultured hepatocytes in rats and human were almost identical and were maintained at a high level between 6 and 24 h after changing the media (rat: 0.908 +/- 0.008 n = 9, human: 0.918 +/- 0.014 n = 6, mean +/- SD). Inhibition of glycolysis with sodium fluoride or oxidative phosphorylation with antimycin A irreversibly reduced both the adenine nucleotide contents and the energy charge. However, the inhibition of fatty acid oxidation with 2-tetradecylglycidic acid did not affect the nucleotide contents, and the energy charge only decreased transiently to recover within 8 h. When the inhibitor of oxidative phosphorylation was removed, the recovery in the energy charge preceded the recovery in the adenine nucleotide contents. These findings suggest that the adenylate energy charge is a more sensitive measure of the changes in energy metabolism than the adenine nucleotide contents. Furthermore, energy charge regulates adenine nucleotide contents in cultured hepatocytes. It is important to confirm that the high energy charge of the cultured hepatocytes is maintained when these cells are used for metabolic studies.

Adenosine Diphosphate↗
PubMed1994

Immediate insertion of two types of implants into vascularized bone grafts used for mandibular reconstruction in miniature pigs.

Reaction of bone tissue was investigated after placement of two different types of implants in vascularized iliac bone grafting. After the mandibles of six Göttingen minipigs were reconstructed with vascularized bone of the iliac crest, hydroxyapatite-coated implants and titanium screw implants were placed in the graft. The animals were killed at 14, 28, and 56 days after the implantation, and the healing processes were examined histologically. In the vascularized bone graft, new bone formed well around the implants, but some of the implant surfaces were covered with soft tissue by advancing bone resorption. The results suggest that a hydroxyapatite-coated implant as well as a titanium screw-type implant might be applied with a vascularized bone graft for jaw reconstruction. However, implants placed simultaneously with the vascularized bone graft had less osteointegration than implants placed in nongrafted control sites.

Animals↗