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Biomedical subjects

Y Toyama

Publications and source records attributed to Y Toyama.

At least 109 records · Page 6Linked to original sources
PubMed1996

Metastases to the upper cervical spine.

A retrospective study of 13 patients with metastases to the upper cervical spine was designed to examine the clinical efficacy of surgical treatment. All patients had severe neck pain and two had quadriplegia. Eleven patients underwent operative posterior stabilization, and two patients were treated with a brace and radiotherapy. Pain relief after surgery was significant so that 10 of the 11 patients could leave bed and resume their normal activities. The other two patients who were treated nonoperatively had severe dementia and sudden death from a respiratory arrest after a fall, despite temporary relief from pain. Surgery may be very successful in improving the quality of life of patients who have pain and/or paralysis caused by metastases to the upper cervical spine.

Adult↗
PubMed1996

Treatment protocol for fractures of the odontoid process.

Treatment results in 104 patients with odontoid fractures were reviewed. There were 2 type I, 62 type II, 32 type III fractures and eight epiphysiolyses in children <7 years old. Thirty-seven patients were managed nonoperatively using plaster casts, cervical braces, or halo devices. Sixty-seven patients were treated surgically including anterior screw fixation (ASF), posterior fusion (PF), and transoral anterior fusion (TAF). Plaster casts and cervical braces were effective for type I fractures and epiphysiolyses only. Halo devices provided successful results in stable type III fractures. ASF is the treatment of choice for most type II and unstable III fractures including some old cases. PF also provided successful union, although impaired cervical motion remained. It should be reserved for irreducible fractures, established nonunions, and as a salvage procedure. TAF should be limited to exceptional cases requiring anterior spinal cord decompression.

Adolescent↗
PubMed1996

Usefulness and reliability of neurological signs for level diagnosis in cervical myelopathy caused by soft disc herniation.

We retrospectively analyzed neurological signs of 106 patients with cervical myelopathy caused by single-level soft disc herniation. Neurological signs that were intensively analyzed were deep tendon reflexes, the uppermost level of impaired pinprick sensation, the uppermost weak muscle, and region of numbness in the hands. Characteristic signs for each intervertebral level were deduced, and sensitivity, specificity, and accuracy of these signs were calculated. Deep tendon reflexes were specific signs for each intervertebral level, although not as sensitive as the neurological signs. Muscle weakness and pinprick sensation were neither sensitive nor specific. Hand numbness was moderately sensitive and specific. On the whole, there was no neurological sign that was both highly sensitive and specific for an intervertebral level, and therefore, neurological level diagnosis in cervical myelopathy should be performed comprehensively according to more specific signs, i.e., deep tendon reflexes and hand numbness.

Adult↗
PubMed1995

Acute hemodynamic improvement by thermal vasodilation in congestive heart failure.

BACKGROUND: A warm-water bath (WWB) or sauna bath (SB) has generally been considered inappropriate for patients with severe congestive heart failure (CHF). However, a comprehensive investigation of the hemodynamic effects of thermal vasodilation in CHF has not been previously undertaken. METHODS AND RESULTS: To investigate the acute hemodynamic effects of thermal vasodilation in CHF, we studied 34 patients with chronic CHF (mean age, 58 +/- 14 years). Clinical stages were New York Heart Association functional class II in 2, III in 19, and IV in 13 patients. Mean ejection fraction was 25 +/- 9%. After a Swan-Ganz catheter was inserted via the right jugular vein, the patient had a WWB for 10 minutes at 41 degrees C or an SB for 15 minutes at 60 degrees C. Blood pressure, ECG, echo-Doppler, expiration gas, and intracardiac pressures were recorded before, during, and 30 minutes after each bath. Oxygen consumption increased mildly, pulmonary arterial blood temperature increased by 1.2 degrees C, and heart rate increased by 20 to 25 beats per minute on average at the end of WWB or SB. Systolic blood pressure showed no significant change. Diastolic blood pressure decreased significantly during SB (P < .01). Cardiac and stroke indexes increased and systemic vascular resistances decreased significantly during and after WWB and SB (P < .01). Mean pulmonary artery, mean pulmonary capillary wedge, and mean right atrial pressures increased significantly during WWB (P < .05) but decreased significantly during SB (P < .05). These pressures decreased significantly from the control level after each bath (P < .01). Mitral regurgitation associated with CHF decreased during and 30 minutes after each bath. Cardiac dimensions decreased and left ventricular ejection fraction increased significantly after WWB and SB. In an additional study, plasma norepinephrine increased significantly during SB in healthy control subjects and in patients with CHF and returned to control levels by 30 minutes after SB. CONCLUSIONS: Hemodynamics improve after WWB or SB in patients with chronic CHF. This is attributable to the reduction in cardiac preload and afterload. Thus, thermal vasodilation can be applied with little risk if appropriately performed and may provide a new nonpharmacological therapy for CHF.

Adolescent↗
PubMed1995

Glucose retention on the surfaces of primary teeth in 3- and 4-yr-old children.

Glucose retention was determined in 38 kindergarten children ages 3-4 yr. The children rinsed their mouths with 10 ml of a 0.5 mol/l glucose solution for 15 s and then spat out. Three minutes after they put the solution in their mouths, a small paper-point was used to collect samples of saliva from the labial and buccal surfaces of the maxillary and mandibular primary teeth. The concentration of glucose in the small amount of saliva collected was measured with an immobilized enzyme system. Glucose retention was highest on the maxillary central primary incisor, second highest on the maxillary first primary molar and third highest on the maxillary lateral primary incisor. An intermediate value was seen on the maxillary and mandibular second primary molars, the mandibular first primary molar and the maxillary primary canine. A lower value was observed on the mandibular primary canine and the lowest on the mandibular incisors. It was concluded that there were site differences in glucose retention on primary teeth of 3- and 4-yr-old children.

Analysis of Variance↗
PubMed1994

Realignment of postoperative cervical kyphosis in children by vertebral remodeling.

STUDY DESIGN: This study analyzed radiographically change in the sagittal curvature of the cervical spine after atlantoaxial (C1-C2) posterior fusion in children. OBJECTIVES: This study clarified the process of spinal remodeling after postoperative cervical deformation in children. SUMMARY OF BACKGROUND DATA: Postoperative spinal deformations in children are observed frequently. However, there have been only a few reports on postoperative changes in the sagittal curvature of the cervical spine and spinal remodeling after those changes. METHODS: Between 1979 and 1991, there was a total of 12 children who underwent C1-C2 posterior fusions. The average age at the time of surgery was 9.8 years. The alignment of the cervical spine was classified into four groups (lordosis, straight, kyphosis, and swan-neck deformity). Radiographic findings suggestive of the remodeling were as follows: 1) new bone formation on the anterior vertebral cortex, and 2) increase in body/canal ratio (BCR). The follow-up period averaged 6.2 years. RESULTS: Postoperative cervical malalignment (kyphosis or swan-neck deformity) occurred in four patients. In all four patients, new bone formation and increase in BCR at the apex of kyphosis were observed. Therefore, there was gradual improvement of the malalignment by vertebral remodeling. This phenomenon was not observed in eight patients with normal alignment. CONCLUSION: Realignment of postoperative cervical kyphosis by vertebral remodeling was observed in children. The results of this study suggested that remodeling occurred even in the spine, which was similar to the remodeling in long bones.

Atlanto-Axial Joint↗
PubMed1994

Neurological evaluation after radical resection of sacral neoplasms.

Eight patients had a radical resection of sacral tumours, and bilateral severance of lumbosacral nerves was required. Their neurological deficits and disturbance of activities of daily living (ADL) were studied. The neurological deficits which occurred were motor dysfunction of the lower limbs, sensory disturbances, and urinary, faecal and sexual dysfunction. Bilateral preservation of the L5 nerve and above was necessary to permit the ability to walk, and bilateral preservation of the S2 nerve and above was necessary to spare urinary, faecal and sexual functions in order to establish ADL. To maintain normal ADL, bilateral preservation of the S2 nerve and above was necessary for walking, and bilateral preservation of the S3 nerve and above was necessary for urinary, faecal and sexual functions.

Activities of Daily Living↗
PubMed1994

Protective effects of an aged garlic extract on doxorubicin-induced cardiotoxicity in the mouse.

Protective effects of an aged garlic extract on the cardiotoxicity of doxorubicin (DOX) was evaluated using the mouse. DOX (1.5 mg/kg body wt i.p.) was administered three times per week for 40 days. An aged garlic extract, WG-1 (a preserved stock solution; Wakunaga Pharmaceutical) was administered intraperitoneally six times weekly. DOX caused changes in the electrocardiogram. In the control mice, the width of the QRS complex was 20 +/- 2.8 milliseconds, the R-R interval was 130 +/- 2.8 milliseconds, and the P-Q interval was 30 +/- 1.4 milliseconds. In mice treated with DOX for 40 days, the width of the QRS complex was 50 +/- 10 milliseconds (p < 0.05), the R-R interval was 240 +/- 30 milliseconds (p < 0.05), and the P-Q interval was 45 +/- 1.0 milliseconds (p < 0.01). These values were significantly smaller in mice treated with WG-1 + DOX than in mice treated with DOX. The width of the QRS complex was 29.3 +/- 5.8 milliseconds (p < 0.05), the R-R interval was 145.8 +/- 17.9 milliseconds (p < 0.01), and the P-Q interval was 37.8 +/- 3.5 milliseconds (p < 0.05). The lipid peroxidation in the heart homogenates prepared from DOX-treated mice, as measured by thiobarbituric acid-reactive substance (TBARS, nmol malondialdehyde/100 mg protein) was 332.5 +/- 67.0, which was significantly larger than that in the control mice (186.6 +/- 42.2) (p < 0.05). WG-1 decreased the level of TBARS in DOX-treated mice significantly. In the mice treated with WG-1 + DOX, TBARS was 221.3 +/- 31.6, which was significantly smaller than that of DOX-treated mice (p < 0.05). Histological study demonstrated that the heart treated with DOX had vacuolization in muscle cells, disrupted myofibrils, and swollen mitochondria. Mice that received WG-1 + DOX had no significant pathological lesions in the heart.

Animals↗
PubMed1994

Mutations that abolish the ability of Ha-Ras to associate with Raf-1.

Recent studies have revealed that Ras can associate physically with Raf. In the present study, we tested 34 mutants of Ha-Ras carrying substitution(s) in the region of residues 23-71 for their ability to associate with Raf-1. Mouse Ba/F3 cell lysates were incubated with each mutant Ras protein, in either the guanosine 5'-[gamma-thio]triphosphate (GTP gamma S)- or the guanosine 5'-[beta-thio]diphosphate (GDP beta S)-bound form, and the anti-Ras antibody Y13-238. The immunoprecipitates were analysed for the presence of Raf-1 by Western blotting with an anti-Raf-1 antibody. Six mutants of Ras, E31K, P34G, T35S, D38N, D57A and A59T, failed to bind Raf-1. Mutations N26G, V29A, S39A, Y40W, R41A, V44A, V45E, L56A and T58A partially reduced the ability to bind Raf-1. All the other mutants could associate with Raf-1 with nearly the same efficiency as that of wild-type Ras. Thus, the Raf-I-binding ability of Ras appears to be affected by mutations in the N-terminal region, and in particular, by those in and neighboring the effector region (residues 32-40) and in the region (residues 56-59) flanking the N-terminal of Switch II. The abilities to bind Raf-1 and to induce neurite outgrowth of pheochromocytoma (PC) 12 cells correlate to each other for 22 Ras mutants. However, mutation A59T, which does not reduce the neurite-inducing or transforming activities, abolishes the ability to bind Raf-1. In contrast, mutations Y32F, K42A and L53A, which impair the neurite-inducing activity of Ras, have no effect on the Ras.Raf-1 association. Partially reduced Raf-1-binding ability was observed for mutants V29A, S39A, Y40W, R41A, V44A, L56A and T58A, which exhibit full neurite-inducing activity, and also for mutant V45E, which has no activity of neurite induction.

Animals↗
PubMed1993

Predictability of operative results of cervical compression myelopathy based on preoperative computed tomographic myelography.

The transverse area and flattening ratio of the spinal cord were determined with preoperative computed tomographic myelography in 103 patients with cervical compression myelopathy: cervical spondylotic myelopathy (n = 44); ossification of the posterior longitudinal ligament (n = 39); and cervical disc herniation (n = 20). With these values and other clinical items (eg, age, duration of symptoms, preoperative severity), a linear model to predict postoperative recovery was attempted by multiple regression analysis. In cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament, the transverse area of the spinal cord and the duration of symptoms were accepted as effective explanatory variables to predict recovery. In cervical disc herniation, regardless of the transverse area or duration, the recovery was good, and pathologic state was considered essentially different.

Cervical Vertebrae↗
PubMed1993

Prenatal diagnosis of fragile X syndrome by direct detection of the dynamic mutation due to an unstable DNA sequence.

The fragile X syndrome is the most common familial form of mental retardation. The mutation causing the syndrome is dynamic mutation due to an unstable DNA (CCG)n repeat localized at Xq27.3. We have previously reported a PCR procedure to prepare a diagnostic probe, pPCRfx1, which can be used to determine the genotype of fragile X mutation individuals by Southern blot analysis. In the present study, pPCRfx1 was applied to the prenatal diagnosis, using chorionic villus cells, of a fetus which was at risk of having fragile X syndrome. In the PstI assay, the Southern blot showed the typical pattern of a female carrier with the full mutation. Analysis of the DNA methylation patterns by EcoRI + EagI assay showed that the EagI restriction site was not methylated on the mutated X chromosome of chorionic villi, but the sites were totally methylated in the brain and other tissues of the fetus. Thus the fetus was diagnosed to be a heterozygous female carrier of the dynamic mutation involved in the fragile X syndrome.

Blotting, Southern↗
PubMed1993

Contrast echocardiography for evaluation of left ventricular flow dynamics using densitometric analysis.

BACKGROUND: Few data exist regarding intraventricular flow patterns in the presence of left ventricular dysfunction. Therefore, we examined the relation between intracavitary left ventricular flow dynamics and the presence of ventricular contractile abnormalities using videodensitometric analysis of transpulmonary contrast echocardiography. METHODS AND RESULTS: Two-dimensional echocardiography was performed before, during, and after intravenous injection of sonicated albumin in 8 normal subjects, 22 patients with infarction, and 6 patients with dilated cardiomyopathy. Time-intensity curves were recorded, and disappearance half-times (in cardiac cycles) were measured for regions of interest at the mitral orifice (Ta) and mid-left ventricular cavity (Tb). We observed contrast enhancement of the left ventricular cavity in 28 of 36 patients. Ta and Tb were identical (19 beats) in all normal patients, but Tb was greater than Ta (19 versus 22 beats, P < .001) in patients with dyssynergy. Patients with dyssynergy were divided in three groups: group A, in whom Tb-Ta < or = 3; group B, in whom Tb-Ta > or = 4; and group C, which was composed of patients without contrast enhancement. Left ventricular end-diastolic dimension was similar in normal patients (46.1 mm) and group A patients (50.3 mm) but was less in each cohort than in groups B (58.7 mm) and C (64.1 mm) (all P < .01). Significant correlation was observed between Tb-Ta and both ejection fraction (r = -.67, P < .001) and wall motion index (r = .62, P < .001). CONCLUSIONS: Clearance of contrast from the mid-left ventricular cavity is prolonged in patients with left ventricular dysfunction. This prolongation may be related to increased left ventricular diastolic volume, impaired intracavitary mixing, or paradoxical systolic flow. Delayed left ventricular contrast washout may have implications regarding the formation of left ventricular thrombi.

Adult↗
PubMed1993

Detection of endogenous avidin-binding proteins in rat liver cells by transblot and electron microscopy.

Peroxidase-conjugated avidin was used to detect the endogenous avidin-binding proteins in rat tissues. By a transblot method, avidin-peroxidase interacted with proteins of mitochondrial fractions of rat liver with estimated molecular weights of 120,000 and 74,000. The proteins were identified as pyruvate carboxylase (120 kDa, pI 6.4) and methylcrotonyl-CoA carboxylase (74 kDa, pI 7.2) by two-dimensional gel electrophoresis and transblot method. The estimated molecular weight of an additional band (220,000) detected in the cytosolic fraction of rat liver was consistent with acetyl-CoA carboxylase. Intense staining also occurred with kidney, heart, ovary and adipose tissue, moderate with large and small intestine, cerebrum and cerebellum, and very faint with testis, lung and spleen. The sections of rat liver embedded in LR white were incubated with avidin-colloidal gold conjugate and examined under an electron microscope. The glutaraldehyde-perfused rat liver blocks were also incubated with streptavidin-ferritin conjugate and the ultrathin sections were cut and examined. The majority of gold and ferritin particles were found in the mitochondria of liver cells. No other cellular compartment was labeled except the cytosol which accounted for approximately 20% of the total labeling of the hepatocytes. The present procedure is a simple, rapid and inexpensive method for detecting the intracellular localization of endogenous avidin-binding proteins in the cells.

Adipose Tissue↗
PubMed1993

Ultrastructural features and pathogenesis of knobbed spermatozoa in a boar.

Ultrastructures of knobbed spermatozoa in a boar were observed. The knobs, found at the apex of the spermatozoa, were spherical swellings of the acrosome; vacuoles were found in the swellings. According to the contents, 2 types of the vacuoles were recognized: a vacuole containing cell debris that was surrounded by 2 or 3 layers of membranes, and a vacuole containing an amorphous material that was surrounded by a single membrane. Several vacuoles might be observed in a knob. Observations of both testes indicated that the cell debris in the vacuole of the knob was derived from the cytoplasm of the Sertoli cell, which evaginated into the spermatid. Origin of the amorphous material in the other type of knob is not known.

Acrosome↗
PubMed1993

The crystal structure of specific granules in human eosinophils studied by thin sectioning and deep-etching with the aid of Fourier transformation.

The crystal structures of specific granules in human eosinophils were studied by thin sectioning and deep-etching with the aid of Fourier transformation. The crystal, thought to be a simple cubic by previous studies by thin sectioning, was demonstrated as the body-centered cubic (the cesium chloride type) consisting of two kinds of particles. The crystal parameters obtained by deep-etching were slightly larger (a = b = c = 4.1-4.4 nm) than by thin sectioning (4.0 nm). By deep-etching, the crystal also showed the stacking folds suggesting the piled-up plates. Although it is known that the patients with hypereosinophilic syndrome have more hypodense eosinophils compared with normal persons, no morphological differences could be detected in the crystals between these eosinophils.

Crystallization↗