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Biomedical subjects

Y Matsui

Publications and source records attributed to Y Matsui.

At least 271 records · Page 15Linked to original sources
PubMed1994

Histomorphometric examination of healing around hydroxylapatite implants in 60Co-irradiated bone.

The purpose of this study was to histomorphometrically evaluate the use of hydroxylapatite (HA) implants in 60Co-irradiated bone. HA implants were installed in rabbit mandibles 3 months, 6 months, and 12 months after 15-Gy irradiation. Nonirradiated rabbits served as controls. The rabbits were killed 7, 14, 30, 60, and 90 days after the HA implantation. The histologic features of the healing process were examined and histomorphometric measurements were made to quantify the percentage of HA-bone contact and trabecular bone in the medullary cavity. In the irradiated groups, although HA-bone contact was observed later than that in the controls, recovery increased with time after irradiation and the rate of HA-bone contact bone-contacting implant surface ratio; BCSR exceeded 90% in all groups examined before 90 days. In the radiated groups, the average trabecular bone-specific volume was lower than that in the controls and began to decrease before BCSR exceeded 90%. Based on the present data, as well as data from the literature, it is suggested that the success rate of HA implants in irradiated bone increases with the interval after radiotherapy. It is also recommended that HA implants in irradiated bone be installed so that bearing by the cortical bone is increased.

Animals↗
PubMed1994

Activation of descending noradrenergic system by peripheral nerve stimulation.

Noradrenaline (NA) release in the rat lumbar spinal cord (L3-4) in response to variable intensity, selective stimulation of large (A-beta), small myelinated (A-delta), and unmyelinated (C) afferent fibers was examined by in vivo microdialysis with high performance liquid chromatography and electrochemical detection. Application of 100 mM K+ solution via the dialysis probe increased NA in the dialysate. Thoracic segment transection rostral to the probe depressed the NA level. Transcutaneous stimulation of peripheral nerves had the following effects: 1) High intensity stimulation of afferent A-delta or C fibers increased spinal NA release, which was decreased by thoracic spinal cord transection. 2) Stimulation of afferent A-beta or A-delta fibers at low intensity did not affect the NA level. 3) High intensity stimulation of afferent A-beta fibers depressed NA release in half of the trials. Results indicate that many NA-containing nerve terminals that innervate the lumbar spinal cord originate from supraspinal structures. Somatic neural inputs from afferent C fibers and high-threshold A-delta, but not A-beta nor low-threshold A-delta fibers, activate the descending NA system and release the NA in the spinal cord. The descending NA system may participate in antinociception.

Animals↗
PubMed1994

Peripheral nerve stimulation increases serotonin and dopamine metabolites in rat spinal cord.

Extracellular serotonin (5-HT), dopamine (DA), and their metabolites, 5-hydroxyindoleacetic acid (5-HIAA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA), were assessed in the rat lumbar spinal cord (L3-4) by in vivo microdialysis with high performance liquid chromatography and electrochemical detection (HPLC-ECD). Under urethane-chloralose anesthesia, basal levels of 5-HT and DA in the dialysates were approximately 1.0-1.2 pg/22 microliters sample, 5-HIAA, DOPAC, and HVA were constant at 322.6 +/- 14.9, 8.6 +/- 0.7, and 10.4 +/- 0.4 pg/22 microliters sample (mean +/- SE), respectively. Local application of 100 mM KCl via the dialysis probe increased the 5-HT and DA. Peripheral nerve stimulation that selectively excited the large (A-beta) or small (A-delta) myelinated fibres increased the metabolites. Excitation of the A-beta fibers increased the levels of 5-HIAA to 138%, DOPAC to 155%, and HVA to 143% of the controls. Stimulation of the A-delta fibers increased 5-HIAA to 121%, DOPAC to 120%, and HVA to 124% of the controls. The results suggest that non-nociceptive peripheral nerve stimulation may activate the descending 5-HT and DA systems in the spinal cord.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Usefulness of magnetic resonance imaging for detecting intrasubstance tear and/or degeneration of lateral discoid meniscus.

In order to determine the usefulness of magnetic resonance imaging (MRI) for detection of intrasubstance tears or degeneration of the lateral discoid meniscus, we compared findings obtained with MRI with those of histological examination. Sixty-four symptomatic lateral discoid menisci were studied using MRI before surgical treatment. Of these, 18 (28%) met the criteria that MRI signals did not extend to the surface and that no visible tears were observable at arthroscopy. Findings of intrameniscal regions of high signal intensity and flattening in shape on MR images were found to represent intrasubstance tears or degeneration not detected at arthroscopy. Our findings thus demonstrate that MRI is more sensitive than arthroscopy in the detection of intrasubstance pathologies of the lateral discoid menisci.

Adolescent↗
PubMed1994

Structural organization of the mouse glycophorin A gene.

The human glycophorin gene has been extensively studied, but information on the homologous gene from other species has been unavailable. Here, we determined the structural organization of mouse glycophorin A gene and compared it with the human gene. The mouse glycophorin gene is a single copy gene while in humans, there are two highly related genes (A and B) that were generated by homologous recombination. Chromosomal mapping indicated that the mouse gene is located in the central region of the mouse chromosome 8, which is syntenic with human chromosomes 4q28-31 where the human glycophorin A gene has been mapped. The mouse gene consists of 8 exons, while the human gene consists of 7 exons and the length of each exon is quite short except for the last exon. The last 4 exons showed extensive homology between the mouse and human genes but divergence in the 5'-exons of the two genes was high. The results suggest that glycophorin genes of mouse and human may have been generated from the same ancestor, but diverged greatly during evolution. The upstream regulatory region of the mouse gene consists of multiple motifs for DNA binding factors that may be required for its erythroid-specific expression.

Animals↗
PubMed1994

Residual left ventricular pump function following acute myocardial infarction in postmenopausal diabetic women.

BACKGROUND: The Framingham Study indicated that women with diabetes mellitus developed cardiac failure four times more often than those without diabetes mellitus after acute myocardial infarction. However, there is little information on residual left ventricular pump function after myocardial infarction in female diabetic patients. METHODS: To evaluate the difference between postmenopausal women and age-matched men in the impact of diabetes mellitus on left ventricular pump function during the first year after myocardial infarction, radionuclide angiography was performed during the third week after acute myocardial infarction and again 1 year later in 50 patients (21 women, 29 men) with diabetes mellitus and 62 patients (25 women, 37 men) without diabetes mellitus. RESULTS: Although the radionuclide angiographic indices did not change during the first year after myocardial infarction in non-diabetic patients, left ventricular end-diastolic volume increased, and the left ventricular ejection fraction, the regional ejection fraction of the non-infarcted area, and the ratio of arterial systolic blood pressure to left ventricular end-systolic volume (pressure:volume ratio) decreased in the diabetic patients. Furthermore, the degree of change in the left ventricular end-diastolic volume, the left ventricular ejection fraction, the regional ejection fraction of the non-infarcted area, and the pressure:volume ratio in diabetic women was larger than that in diabetic men. CONCLUSION: The increase in the left ventricular end-diastolic volume and the decrease in the regional ejection fraction of the non-infarcted area during the first year after myocardial infarction in postmenopausal women with diabetes mellitus indicate that female sex associated with diabetes mellitus may be important factors in left ventricular remodeling in postmenopausal women.

Aged↗
PubMed1994

Annular elastolytic giant cell granuloma: response to cyclosporin A.

A case of annular elastolytic giant cell granuloma with a good response to cyclosporin A is reported. A 62-year-old man developed multiple annular patches on the trunk with elevated and indurated borders. Biopsy specimens from the border showed granulomatous inflammation in the mid dermis with phagocytosis of elastic fibers by giant cells. Biopsy specimens from the center showed dense collagen formation without inflammation. Immunological investigation of perivascular infiltrating cells in the lesions revealed a predominance of CD4+ cells over CD8+ cells. Our case showed a good response to cyclosporin A (5 mg/kg/day) for eight weeks. There were no adverse effects and no recurrences for one month after discontinuation of cyclosporin A.

Cyclosporine↗
PubMed1994

Proliferating cell nuclear antigen (PCNA) and p53 protein expression in Bowen's disease.

Bowen's disease is a premalignant dermatosis comprised of a clonal proliferation of atypical keratinocytes in the full thickness of the epidermis. To elucidate the relationship between the alteration of the p53 tumor suppressor protein and cell proliferation rate, we immunohistochemically examined the expression of proliferating cell nuclear antigen (PCNA) and p53 protein in 30 cases of Bowen's disease. All the cases exhibited the full-thickness distribution of PCNA-positive cycling cells in the lesional epidermis. Quantitation of PCNA staining by image cytometry revealed a mean labeling index (LI) of 75.1 +/- 20.3. p53 expression was detected in 13 cases (43%). Expression was diffuse (p53 LI > 50) in 9 cases, but focal (p53 LI < 30) in the other four. The mean PCNA LI of p53 diffusely positive cases was significantly greater than that of both p53 focally positive and p53 negative cases (89.3 +/- 10.1 vs 62.7 +/- 21.2, and 70.5 +/- 21.6; p < 0.01, respectively). These findings suggest that a high-level accumulation of p53 protein results in a more increased cell proliferation in Bowen's disease.

Aged↗
PubMed1994

Oral administration of BOF-A2 to rats with lung transplanted tumors results in increased 5-fluorouracil levels.

A new tumor model was developed in which solid Yoshida sarcoma tissue injected intravenously developed into tumors in the lungs of about 30% (13/42) of the inoculated rats. Histological examination revealed that alveoli were occupied with tumor cells and the tumors were similar to those obtained by subcutaneous inoculation. Using this model, the concentrations of 5-fluorouracil (5-FU) in tumor tissue 12 h after oral administration of 3-[3-(6-benzoyloxy-3-cyano-2-pyridyloxycarbonyl)-benzoyl]-1-ethoxy methyl- 5-fluorouracil (BOF-A2, 36 mumol/kg) or a combination of tegafur and uracil in a molar ratio 1 to 4 (UFT, 50 mumol/kg) were found to be 129.8 ng/g and 19.2 ng/g, respectively. Thus, compared to treatment with UFT, BOF-A2 resulted in higher levels of 5-FU in lung tumor tissues. Increased concentrations of 5-FU should have a superior anti-tumor effect and so BOF-A2 merits clinical trial in the treatment of patients with lung cancer.

Administration, Oral↗
PubMed1994

The yeast TEM1 gene, which encodes a GTP-binding protein, is involved in termination of M phase.

LTE1 belongs to the CDC25 family that encodes a guanine nucleotide exchange factor for GTP-binding proteins of the ras family. Previously we have shown that LTE1 is essential for termination of M phase at low temperatures. We have identified TEM1 as a gene that, when present on a multicopy plasmid, suppresses the cold-sensitive phenotype of lte1. Sequence analysis of TEM1 and GTP-binding analysis of the gene product revealed that TEM1 encodes a novel low-molecular-weight GTP-binding protein. The defect of TEM1 was lethal, and the tem1-defective cells were arrested at telophase with high H1-kinase activity under restrictive conditions, indicating that TEM1 is required to exit from M phase. The defect of TEM1 was suppressed by a high dose of CDC15, which encodes a protein kinase homologous to mitogen-activated protein kinase kinase kinases. The genetic interaction among LTE1, TEM1, and CDC15 indicates that they cooperatively play an essential role for termination of M phase.

Amino Acid Sequence↗
PubMed1994

Electroretinogram b/a wave ratio improvement in central retinal vein obstruction.

The electroretinogram (ERG), especially the b/a wave ratio, is considered a good indicator of retinal ischaemia in central retinal vein obstruction (CRVO). Seven CRVO patients who showed b/a wave ratio improvement from < 1.0 [negative type (-) ERG] to > or = 1.0 and one from 1.07 to 1.53 were studied. Three mechanisms of change were observed: firstly, the b-wave amplitude increased without an a-wave amplitude decrease (group A, n = 2); secondly, the b-wave amplitude increased with an a-wave amplitude decrease (group B, n = 4); and, thirdly, both decreased, but the a-wave amplitude decreased more markedly (group C, n = 2). In group A, the visual acuities improved markedly. In group B, the visual acuities improved in two cases in which the b-wave amplitude reached the normal range; the visual acuities did not improve in two cases in which the b-wave amplitude did not reach the normal range. In group C, the visual acuities remained poor. The negative (-) ERG or significantly reduced b/a wave ratio is associated with ischaemic CRVO and did not occur because of the filtering effect of the haemorrhage, which may reduce the stimulus light for the ERG. Improvement of the reduced b/a wave ratio with an increased b-wave amplitude was accompanied by improvements in fundus appearance and visual acuity in CRVO. The results suggest that the retinal ischaemia in CRVO, as revealed by the ERG and fluorescein angiogram, may be reversible in some cases.

Adult↗
PubMed1994

Effect of ventriculoarterial coupling on residual left ventricular pump function in diabetic patients with myocardial infarction.

To study the ventriculoarterial coupling in diabetic patients with myocardial infarction (MI), 26 diabetic and 34 nondiabetic patients were investigated using radionuclide angiography in the 3rd week after acute MI. Effective arterial elastance was nearly one half of left ventricular end-systolic elastance in nondiabetic patients. On the other hand, effective arterial elastance was twice left ventricular end-systolic elastance in diabetic patients. These data suggest that a decrease in left ventricular contractility and an increase in effective arterial elastance lead to increased potential energy and decreased work efficiency in diabetic patients.

Arteries↗
PubMed1994

Snellen visual acuity versus pattern reversal visual-evoked response acuity in clinical applications.

We compared the best-corrected Snellen acuity (SA) and the pattern reversal visual-evoked response (PVER) acuity in normal subjects and patients. Forty-two eyes of 42 normal subjects were controls; 457 eyes of 329 patients comprised the patient group. A steady-state stimulus with five check sizes ranging from 160 to 10 min in 1.0-octave steps was used. The PVER acuity was derived from the best-fit linear function relating the amplitude to the log-adjusted check size. Three intercepts of 0, 1 and 2 microV were used in both groups, and the PVER acuities were called P0, P1 and P2. The SAs in normal subjects ranged from 20/15 to 20/20 (mean, 20/18.3) and in patients from 20/15 to 20/1,600 (mean, 20/56.9). In normals, the P0 showed the best agreement with the SA (mean acuity difference, +0.34 octave). The SA and P0 agreed within +/- 2.0 octaves in 33/42 (78.6%) eyes. In patients, the P0 also showed the best agreement with the SA; 306/457 (67.0%) eyes showed an acuity difference within +/- 2.0 octaves. Unlike normals, 83/457 (18.2%) eyes showed an acuity difference > -3.0 octaves. These eyes mostly had optic nerve disease with a flattened PVER amplitude-check size function curve. The P0 seems to correlate better with SA than P1 and P2, but this analytical method may be less effective in the presence of certain pathologic conditions.

Adolescent↗
PubMed1994

Risk factors for carotid atherosclerosis and platelet activation.

Thromboxane A2 biosynthesis was studied in healthy subjects, in patients in whom the extent of carotid atherosclerosis was determined, and in patients receiving chronic aspirin treatment, to determine what factors activate platelets to develop carotid atherosclerosis. Urinary 11-dehydrothromboxane B2, a major metabolite of thromboxane A2, was measured by radioimmunoassay after purification by reverse-phase HPLC. The extent of carotid atherosclerosis was determined by real-time B-mode ultrasonography. The severity of carotid atherosclerosis in each subject was evaluated by plaque score, which was computed by summing the maximum thickness of plaque measured in millimeters. Urinary excretion of 11-dehydrothromboxane B2 in healthy subjects was higher (P < 0.01) in cigarette smokers (1063 +/- 244 ng/g creatinine) than in non-smokers (815 +/- 183 ng/g creatinine). Aspirin significantly suppressed 11-dehydrothromboxane B2 excretion (266 +/- 114 ng/g creatinine). In the 24 patients in whom the plaque score was measured, multivariate analysis indicated a significant positive correlation between urinary excretion of 11-dehydrothromboxane B2 and plaque score, age, smoking and hypercholesteremia. Our results indicate that risk factors such as age, hypercholesteremia, atherosclerosis and smoking activate platelets in vivo to develop carotid atherosclerosis.

Adult↗
PubMed1994

Ultrastructural observation of Pneumocystis carinii in bronchoalveolar lavage fluid from non-AIDS patients with P carinii pneumonia.

To investigate the morphology of Pneumocystis carinii in vivo, we studied the ultrastructure of P carinii in bronchoalveolar lavage fluid (BALF) obtained from four non-AIDS patients with P carinii pneumonia (PCP), and observed the morphologic changes after treatment in one patient. Every form recognized in the normal life cycle of P carinii, ie, thick-walled cysts, crescent-shaped cysts, and trophozoites, was detected in the pretreatment BALF specimens. In the posttreatment BALF, P carinii revealed marked ultrastructural changes such as the elongation of thick-walled cysts, the degeneration of intracystic bodies, and the disappearance of trophozoites. Massive debris derived from P carinii was still found in the BALF even after the treatment. Examination of P carinii in BALF, including ultrastructural observations, might help us to evaluate the disease status and the effect of treatment in patients with PCP.

Aged↗
PubMed1994

Reactions of bone tissue in old rats to three different implant materials.

This study compares the bone responses of old rats when implanted with hydroxyapatite ceramic (HAC)-coated titanium, high-density HAC, and uncoated titanium. Twelve two-year-old Wistar rats were used in this study. Cylindrical implants were placed into each tibia, and the animals were killed seven, 14, 28, or 56 days after implantation. Undecalcified sections were prepared and were then stained with toluidine blue. The healing process was examined histologically, and histomorphometric measurements were made with a computer-based image analyzer to quantify the percentage of implant-bone contact. The results indicated that the HAC-coated implants were superior to the uncoated titanium implants in relation to bone contact. In the cases where the bone-free surface of HAC coating was dissolved, macrophages were often seen on the surface of the implant. Although further longitudinal data are needed to evaluate the decrease of HAC coating, in this animal model, HAC-coated implants may be useful for osseous response in bones of poor quality.

Age Factors↗
PubMed1994

[Clinical results of selective cerebral perfusion during reconstruction of the transverse aortic arch].

Selective cerebral perfusion (SPC) has become a reliable method for brain protection during reconstruction of the transverse aortic arch. However, arterial cannulation technique for the branches of the aortic arch varies among groups, and the necessity of perfusion for the left subclavian artery is controversial. To avoid atheroembolism to the brain and malperfusion of the vertebral arterial system, we carefully selected the arterial cannulation technique according to the result of preoperative ultrasonographic and angiographic evaluation of the branches of the aortic arch, and decided the necessity of perfusion for the left subclavian artery according to the dominance of the two vertebral arteries and the result of pressure monitoring of all three branches. In this report, we analyzed our clinical results of selective cerebral perfusion on 22 consecutive patients, which was performed between April 1992 and December 1993. There were 14 atherosclerotic aneurysms and 8 aortic dissections. The flow rate for SCP was controlled by a single blood pump separate from that for systemic perfusion, with the mean value being 13.1 ml/kg/min. Mean of minimum left superficial temporal arterial pressure was 51 mmHg, mean duration of SCP was 134 minutes, and mean of the lowest esophageal temperature was 17.9 degrees C. Blood pH was regulated with alpha-stat strategy. Arterial cannula for SCP was inserted directly into the vessels through a stab wound in most cases. In three of four patients in whom dissection extended to the branches, a balloon catheter was introduced through the lumen of the aortic arch.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗