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Biomedical subjects

K Kaneko

Publications and source records attributed to K Kaneko.

At least 73 records · Page 4Linked to original sources
PubMed2001

Intramedullary schwannoma of the spinal cord: report of two cases.

We report magnetic resonance findings in the intramedullary schwannoma of the cervical spinal cord in two patients. In both cases, the solid portions of the tumours enhanced intensely after administration of Gd-DTPA and the enhanced border was sharply delineated from the adjacent spinal cord. Schwannomas should be considered in the differential diagnosis of intramedullary tumours when magnetic resonance images show a strongly enhancing mass with sharply delineated borders.

Adolescent↗
PubMed2001

MRI in seven cases of tacrolimus (FK-506) encephalopathy: utility of FLAIR and diffusion-weighted imaging.

We assessed the utility of fluid-attenuated inversion-recovery (FLAIR) and diffusion-weighted (DWI) images in investigation of tacrolimus (FK-506) encephalopathy, and to see whether we could predict its cause from clinical and imaging data. In seven patients with presumed FK-506 toxicity the areas involved on MRI were similar to those in cyclosporin A (CsA) toxicity. The abnormal signal was most evident on FLAIR in all cases. In three of four patients who underwent DWI, no diffusion abnormalities were detected; in the remaining patient, increased diffusion was seen in the deep white matter bilaterally on the apparent diffusion coefficient map, consistent with the findings on T2-weighted spin-echo and FLAIR images. Five of the six patients for whom we had clinical data showed sudden changes in electrolyte or fluid equilibrium due to diarrhoea, a polyuria or oliguria one day before or on the day of onset of the central nervous system disturbances. We speculate that FK-506 encephalopathy is triggered by the disturbance of the electrolyte and/or fluid equilibrium, given a certain serum level of FK-506.

Adolescent↗
PubMed2001

Endoscopic carpal tunnel release and nerve conduction studies.

We investigated the outcome of endoscopic carpal tunnel release (ECTR) for patients with carpal tunnel syndrome (CTS) in comparison with the results of preoperative nerve conduction studies. The compound muscle action potential (CMAP) of the abductor pollicis brevis muscle (APB) and the second lumbrical muscle (L2) was recorded following median nerve stimulation at the wrist. A total of 38 hands in 35 patients were classified into four categories. Hands with a similarly prolonged distal motor latency for the APB and L2 were classified as type I (n=25), while those with a more prolonged distal motor latency for the APB than for the L2 (>0.7 ms) were classified as type 2 (n=10). Hands with a CMAP for the APB, but not L2, were classified as type 3 (n=1), and hands with no CMAP for either the APB or L2 were classified as type 4 (n=2). After ECTR, all of the type 1 and 2 hands were improved. Patients with type 3 and type 4 hands did not show satisfactory improvement, which may have been due to anatomical variation of the recurrent motor branch of the median nerve.

Action Potentials↗
PubMed2001

Incidence of intrauterine complications in monoamniotic twin gestation.

We compared the incidence of intrauterine complications, such as twin-twin transfusion syndrome, between monochorionic-monoamniotic (MM) and monochorionic-diamniotic (MD) twin gestations. We retrospectively evaluated a series of 11 MM and 211 MD twin gestations managed after 22 weeks' gestation at our hospitals. One MM twin gestation was diagnosed with twin-twin transfusion syndrome based on clinical presentation of polyhydramnios and hydrops. The incidence of twin-twin transfusion syndrome in MM twin gestations (9.1%) was not measurable different from that in the MD twin gestations (7.6%, p=0.09). There were no measurable differences in the incidence of other complications, such as growth discordance >25% or intrauterine fetal demise between the two groups. MM twin gestations should be kept under close management while carefully monitoring for any circulatory imbalance between the twins.

Adult↗
PubMed2001

Nonlinear digital hearing aid with near-instantaneous amplitude compression.

We designed a new type of nonlinear digital hearing aid (TD-1) with near-instantaneous amplitude compression for sensorineural hearing-impaired people. The amplification method utilized by the TD-1 normalizes the signal waveforms within a time window bounded by two adjacent positive going zero-crossing points. The signals within this window are amplified so that the maximum amplitude reaches a preset value, thus allowing a consistent peak amplitude to be maintained. To test this, we examined the efficacy of the TD-1 device in 31 patients with sensorineural hearing loss. When tested for recognition of Japanese sentences in a quiet environment, 7 of 25 (28.0%) subjects wearing the TD-1 showed a 20% or greater increase in the maximum intelligibility score than that obtained when wearing their own linear hearing aids. In addition, 7 of 31 (22.6%) subjects showed the same increase with the TD-1 relative to that obtained when they wore HA70 or HA73 devices (Rion Co., Ltd., Tokyo, Japan), which are conventional analogue hearing aids. These results indicate that TD-1 can be effective for patients with sensorineural hearing loss.

Adolescent↗
PubMed2001

Angiotensin converting enzyme gene polymorphism in primary vesicoureteral reflux.

We studied the insertion/deletion (I/D) polymorphism of the angiotensin converting enzyme (ACE) gene in 78 patients with primary vesicoureteral reflux (VUR), and examined renal function by dimercaptosuccinate (DMSA) renoscintigraphy and diethylenetriamine-penta-acetic acid (DTPA) renogram in each genotype. Patients were classified into three genotypes according to the ACE gene I/D polymorphisms: 32 in II genotype, 36 in ID, and 10 in DD. The incidence of presumably congenital unilateral small kidneys was high in DD patients (70%). Glomerular filtration rate obtained from DTPA renogram was 120.7+/-35.7 ml/min (expressed as mean+/-SD) in II genotype, 111.7+/-33.3 in ID, and 88.0+/-18.0 in DD. The total quantitative DMSA tracer uptake of both kidneys was also low in patients with the D allele. This study shows that the D allele of ACE gene is closely related to small congenital kidneys with refluxing ureters in patients with primary VUR, and in accordance with previous reports, this allele is also related to the progression of reflux nephropathy.

Alleles↗
PubMed2001

Combined pharmacotherapy for nocturnal enuresis.

Nocturnal enuresis is a common childhood disorder. Tricyclic antidepressants and anticholinergic agents have been the well accepted pharmacological treatment for this disorder and are efficacious in 40-70% and 10-50% of cases, respectively. The present study was performed to evaluate the effect of a combined treatment of tricyclic antidepressant and an anticholinergic agent. Twenty-two children aged 6-12 years with primary monosymptomatic nocturnal enuresis who did not prefer to use a conditioning alarm were given a combined treatment of these drugs. After a control period of 1 month, each patient was treated for 6 months and then observed for 3 months. A 30-mg dose of amitriptyline or imipramine was given with either 2-4 mg oxybutinin or 10-20 mg propiverine. Efficacy was determined relative to the number of wet nights per week compared with the control period, with more than a 50% decrease in wet nights per week taken to indicate efficacy. The mean wet nights per week decreased from 6.1 to 1.7 (P<0.01), and efficacy was established in 20 patients (90.9%). Relapses occurred in 60.0% of patients during the follow-up period. No significant side effects were observed. The efficacy of the combined therapy in monosymptomatic nocturnal enuresis appears to be greater than that reported for either drug alone, and therefore can be a choice of treatment in order to motivate children with nocturnal enuresis.

Amitriptyline↗
PubMed2001

Nutcracker phenomenon demonstrated by three-dimensional computed tomography.

We report a 15-year-old girl with nutcracker syndrome (NCP) in whom three-dimensional helical computed tomography (3D helical CT) was useful for diagnosis; angiographic imaging using 3D helical CT provided fine outlines of the vascular structures in NCP, i.e., a compression of the left renal vein between the aorta and the superior mesenteric artery and the abnormal acute angle between them. Thus, a 3D helical CT enables precise depiction of the anatomical characteristics of renal vasculature and, therefore, may be a useful alternative imaging technique instead of conventional examinations, such as invasive venography or digital subtraction angiography. Further study in a large number of children with vascular abnormalities would be worthwhile.

Adolescent↗
PubMed2001

Prognostic value of p53 mutations in patients with locally advanced esophageal carcinoma treated with definitive chemoradiotherapy.

PURPOSE: A significant correlation has been found between p53 mutation and response to chemotherapy or radiotherapy. To determine the prognostic value of p53 mutation in patients with locally advanced esophageal carcinoma treated with definitive chemoradiotherapy, p53 mutation was analyzed using the biopsied specimens taken for diagnosis. METHODS: Concurrent chemoradiotherapy was performed for 40 patients with severe dysphagia caused by esophageal squamous cell carcinoma associated with T3 or T4 disease. Chemotherapy consisted of protracted infusion of 5-fluorouracil, combined with an infusion of cisplatinum. Radiation treatment of the mediastinum was administered concomitantly with chemotherapy. The p53 gene mutation was detected by fluorescence-based polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) methods. DNA sequences were determined for DNA fragments with shifted peaks by SSCP methods. RESULTS: Of the 40 patients, 15 had T3 disease and 25 had T4 disease; 11 patients had M1 lymph node (LYM) disease. Of the 40 patients, 13 (33%) achieved a complete response. The median survival time was 14 months, and the 2-year survival rate was 20%. Among the 40 tumor samples, p53 mutation was detected in 24 tumors (60%). The survival rate in the 24 patients with p53 mutation did not differ significantly from that in the 16 patients without p53 mutation. In contrast, the 15 patients with T3 disease survived longer than the 25 patients with T4 disease (P = 0.016); however, the survival rate in the 11 patients with M1 LYM disease did not differ significantly from that in the 29 patients without M1 LYM disease. CONCLUSION: Concurrent chemoradiotherapy is potentially curative for locally advanced esophageal carcinoma, but p53 genetic abnormality has no impact on prognosis.

Aged↗
PubMed2001

Gastrointestinal stromal tumor of the lesser omentum: report of a case.

We describe herein an extremely unusual case of a gastrointestinal stromal tumor (GIST) of the lesser omentum. A 45-year-old man was admitted to our hospital with an intra-abdominal mass that was subsequently misdiagnosed as a submucosal tumor of the stomach. The tumor arose from the lesser omentum and was removed without difficulty. Histologically, the tumor was composed of spindle-shaped cells with an interlacing bundle pattern, and immunohistochemical examination showed that it was positive for myeloid stem cell antigen (CD34), but negative for HHF35 and S-100 protein. These findings were consistent with a GIST lacking myogenic features and neural attributes. The patient had an uneventful postoperative course, and was free of recurrence when last seen 11 months after his operation.

Gastrointestinal Neoplasms↗
PubMed2001

Analysis of the human pancreatic secretory trypsin inhibitor (PSTI) gene mutations in Japanese patients with chronic pancreatitis.

Chronic pancreatitis (CP) is a continuing or relapsing inflammatory disease of the pancreas. Several studies have demonstrated that mutations in the cationic trypsinogen (PRSS1) gene and the cystic fibrosis transmembrane conductance regulator (CFTR) gene are causative of the pathogenesis in a subset of hereditary and/or idiopathic CP cases. Recently, the N34S alteration of the pancreatic secretory trypsin inhibitor (PSTI) gene has been suggested to be closely associated with the pathogenesis of hereditary and/or idiopathic CP. Herein we analyzed genetic alterations of the PSTI gene in 32 unrelated Japanese CP patients who developed juvenile-onset CP or had a family history of CP; 5 patients were found to harbor alterations in this gene. In 3 of these 5 patients, heterozygous N34S alterations were found; this frequency is significantly lower than that in Caucasian patients reported previously. Moreover, a novel homozygous G-to-A transition in the promoter region of PSTI at 215bp upstream from the translation initiation site (-215G>A) was observed in 2 patients. We further surveyed the -215G>A alteration in 117 normal individuals; none of these individuals harbored this alteration. Our results suggested that the -215G>A alteration, as well as the N34S alteration, is a predisposing factor for CP.

Adolescent↗
PubMed2001

Clinical efficacy of telemedicine in emergency radiotherapy for malignant spinal cord compression.

The authors developed a Telecommunication-HElped Radiotherapy Planning and Information SysTem (THERAPIST), then estimated its clinical benefit in radiotherapy in district hospitals where consultation with the university hospital was required. The system consists of a personal computer with an image scanner and a digital camera, set up in district hospitals and directly connected via ISDN to an image server, and a treatment planning device set up in a university hospital. Image data and consultative reports are sent to the server. Radiation oncologists at the university hospital determine a treatment schedule and verify actual treatment fields. From 1998 to 1999, 12 patients with malignant spinal cord compression (MSCC) were treated by emergency radiotherapy with the help of this system. Image quality, transmission time, and cost benefit also were satisfactory for clinical use. The mean time between the onset of symptoms and the start of radiotherapy was reduced significantly from 7.1 days to 0.8 days (P < .05) by the introduction of the system. Five of 6 nonambulant patients became ambulant after the introduction of THERAPIST compared with 2 of 8 before the introduction of THERAPIST. The treatment outcome was significantly better after the introduction of the system (P < .05), and suggested to be beyond the international standard. The telecommunication-helped radiotherapy and information system was useful in emergency radiotherapy in district hospitals for patients with MSCC for whom consultation with experienced radiation oncologists at a university hospital was required.

Cost-Benefit Analysis↗
PubMed2001

Alpha-tocopherol affects the urinary and biliary excretion of 2,7,8-trimethyl-2 (2'-carboxyethyl)-6-hydroxychroman, gamma-tocopherol metabolite, in rats.

In this study, we investigated a change in the excretory content of 2,7,8-trimethyl-2(2'-carboxyethyl)-6-hydroxychroman (gamma-CEHC), a gamma-tocopherol (gamma-Toc) metabolite, in rat urine and bile by using a new high-performance liquid chromatography-electrochemical detection (HPLC-ECD) method. In this determination, CEHC [alpha- and gamma-CEHC, where alpha-CEHC = 2,5,7,8-tetramethyl-2(2'-carboxyethyl)-6-hydroxychroman] in the biological specimens were treated with 3 N methanolic HCl to hydrolyze conjugates and to promote esterification. The methylated samples were extracted by n-hexane/water (1:2). The analyses of the methyl esters of alpha-CEHC and gamma-CEHC were performed by an HPLC-ECD using an ODS-3 column at 35 degrees C. The mobile phase was acetonitrile/water (45:55, vol/vol) containing 50 mM sodium perchlorate. After rat urine and bile samples, respectively, were methylated as described above, methylated biliary metabolites were identified by liquid chromatography-mass spectrometry as methyl esters of gamma-CEHC. Furthermore, we examined the differences in the excretion of gamma-CEHC between rat urine and bile after an oral administration of gamma-Toc or alpha- + gamma-Toc by the above HPLC method. In the gamma-Toc group, each vitamin E-deficient rat was given 0.5 mL of a stripped corn oil preparation containing 10 mg of gamma-Toc. In the alpha- + gamma-Toc group, the rat was given 10 mg of alpha-Toc and 10 mg of gamma-Toc. The content of gamma-CEHC in rat urine from the alpha- + gamma-Toc group was increased more in comparison to the gamma-Toc group at 18-36 h after oral administration. Moreover, the content of gamma-CEHC in rat bile in the alpha- + gamma-Toc group was increased more in comparison to the gamma-Toc group at 6-18 h after oral administration. Therefore, we have suggested that gamma-CEHC was shifted mainly to urinary excretion after gamma-CEHC had been excreted into the bile. Furthermore, we assume that alpha-Toc may affect the metabolism of gamma-Toc to gamma-CEHC in the body.

Animals↗
PubMed2001

Pulmonary surfactant protein A in sera for assessing neonatal lung maturation.

To examine whether surfactant protein A (SP-A) in postnatal serum can predict the development of respiratory distress syndrome (RDS), we analyzed the relationship between serum concentrations of SP-A and the risk of RDS using sera from neonates within 24 h after birth. A total of 104 blood samples including 23 samples from newborn infants with RDS were obtained. SP-A content in sera was measured with an enzyme-linked immunosorbent assay system consisting of a standard of native SP-A and two monoclonal antibodies against human SP-A. The level of serum SP-A increased with advancing gestation. Since the mean level of serum SP-A in patients with RDS (3.8 ng/ml) was significantly lower than those without RDS (12.0 ng/ml) (P<0.001), we calculated the diagnostic index values at various cutoff points and chose cutoff values to predict the risk of RDS. Maximum diagnostic value of 85% was obtained at a cutoff point of 3.8 ng/ml (sensitivity 57% and specificity 93%). We also chose a cutoff value of 2.1 ng/ml for definitive diagnosis of RDS, and 8.3 ng/ml for exclusive diagnosis of RDS. The adjusted odds ratios of RDS was significantly elevated when SP-A concentration in serum was under the cutoff values. The presence of SP-A in cord blood serum was also confirmed by immunoblotting analysis. We emphasize the value of SP-A examination in cord blood or postnatal serum from infants who exhibited respiratory difficulties at birth. We believe that our results are consistent with the hypothesis that SP-A is a useful serum marker in predicting the development of RDS.

Biomarkers↗
PubMed2001

A new rabbit model for the study on cervical compressive myelopathy.

Development process and pathology of myelopathy due to chronic spinal cord compression have not been fully elucidated. This study was conducted in order to establish an experimental model which can efficiently produce myelopathy and be useful in the studies on myelopathy due to chronic spinal cord compression. Under electrophysiological monitoring of the spinal cord, anterior compression was produced on C5 using a plastic screw. Two weeks later, a plastic plate was inserted under the C5 arch. For the subsequent 10 months on average, walking pattern and MR images were periodically monitored. Before the sacrifice, electrophysiological test was performed and then histopathological examination was done. Palsy appeared at 5 months on average after the addition of posterior compression. Mean compression ratio of the spinal cord calculated on MR images was 34%. All animals with compression showed a high intramedullary signal intensity, and the mean contrast-to-noise ratio (CNR) in the compressed area was 49%. Electrophysiological test showed a significant decrease in the amplitude of spinal cord evoked potentials (SCEPs) at the given compression level. Histology showed flattening of the anterior horn, disappearance and necrosis of anterior horn cells in the gray matter; and demyelination and axonal degeneration in the white matter. The antero-posterior compression produces the condition of spinal canal stenosis. Repeated antero-posterior compression to the spinal cord is important in establishing myelopathy. The present animal model was evaluated to be useful in the studies on myelopathy.

Animals↗
PubMed2001

Mechanism of prolonged central motor conduction time in compressive cervical myelopathy.

OBJECTIVE: To investigate the mechanism of prolonged central motor conduction time (CMCT) in compressive cervical myelopathy, we compared the calculated CMCT following transcranial magnetic stimulation (TCM) and evoked spinal cord potentials (ESCPs) following transcranial electric stimulation (TCE). METHOD: Motor evoked potentials following TCM were recorded from abductor digiti minimi and abductor hallucis brevis muscles in 16 patients with compressive cervical myelopathy. CMCT was calculated by subtracting peripheral conduction time using peripheral nerve stimulation from MEP latency. ESCPs following TCE were recorded intraoperatively from posterior epidural space. RESULTS: CMCT was prolonged and significant attenuation of the ESCP amplitude following TCE was observed in all patients with cervical myelopathy. In 8 of 16 patients CMCT was significantly prolonged but ESCPs were recorded at the C6-7 level with normal negative peak latency. CONCLUSIONS: Prolonged CMCT may occur with only a minor amount of conduction slowing in the corticospinal tract in compressive cervical myelopathy. Impaired temporal summation of multiple descending potentials following TCM produced delays of motor neuron firing that contribute to the mechanism of prolonged CMCT.

Aged↗