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Biomedical subjects

K Nobuhara

Publications and source records attributed to K Nobuhara.

At least 19 recordsLinked to original sources
PubMed2006

Frontal white matter anisotropy and symptom severity of late-life depression: a magnetic resonance diffusion tensor imaging study.

OBJECTIVES: To investigate the disruption of neural circuits in the frontal lobes and limbic structures in late-life depressed patients compared with healthy controls, and to examine the correlation between the degree of microstructural abnormalities of white matter and clinical symptom severity in late-life depression. METHODS: Thirteen patients with late-life depression and matched control subjects underwent diffusion tensor imaging. Fractional anisotropy (FA), an index of the integrity of white matter tracts, was determined in the white matter of frontal, temporal, and occipital brain regions and the corpus callosum. RESULTS: A significant reduction was found in white matter FA values of widespread regions of the frontal and temporal lobes of depressed patients. Also, there was some evidence suggesting that white matter FA values of the inferior frontal brain region are inversely related to severity of depression. CONCLUSIONS: These results suggest the possible loss of integrity within frontal and temporal white matter fibre tracts and implicate the orbitofrontal circuit in symptom severity in late-life depression.

Anisotropy↗
PubMed2004

Effects of electroconvulsive therapy on frontal white matter in late-life depression: a diffusion tensor imaging study.

This study was conducted to elucidate the effects of electroconvulsive therapy (ECT) on frontal white matter in late-life depressed patients. Diffusion tensor imaging was performed on 8 late-life depressed patients and 12 healthy age-matched controls. The patients were scanned before and after a course of ECT. Fractional anisotropy (FA) was determined in the frontal and temporal regions and the corpus callosum. A significant white matter FA reduction was found in widespread frontal and temporal brain regions in patients with depression before ECT treatment compared with controls. A significant increase in frontal white matter FA was seen following ECT treatment. A course of bilateral ECT ameliorated white matter integrity in frontal brain regions. This suggests a strong relationship with the antidepressant action of ECT.

Age of Onset↗
PubMed2003

Diffusion tensor magnetic resonance imaging of disruption of regional white matter in schizophrenia.

Diffusion tensor imaging provides a new approach for quantifying anisotropic diffusion of white matter in vivo. We used this technique to investigate subtle disruption of regional white matter in schizophrenia. Twelve patients with schizophrenia were compared with 11 healthy controls. Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale. A significant fractional anisotropy (FA) reduction was found in all white matter regions bilaterally in schizophrenic patients. Higher FA of left frontal white matter correlated significantly with higher dosage of antipsychotic medication. These findings support the view that the pathological process is a distortion of the central nervous system myelination affecting the whole white matter. Our findings also show the effects of antipsychotics on the white matter in the left frontal region in schizophrenia.

Adult↗
PubMed2003

Prognostic indicators for outcome following rotator cuff tear repair.

PURPOSE: To examine the prognostic indicators associated with outcome following rotator cuff surgery. METHODS: A retrospective evaluation of records on 1120 shoulders (1067 patients) with rotator cuff tear treated by surgery was performed. Preoperative, intra-operative and postoperative factors were analysed by Kendall's Tau-b correlation analysis and logistic regression analysis. RESULTS: Positive correlations were seen between the type of tear and the number of tendons involved, retraction, age, degeneration, subacromial bone spur, surgical technique, preoperative and postoperative muscle power, surgical outcome, and preoperative abduction on Kendall's Tau-b analysis. There was a positive correlation seen between degenerative change and age, number of tendons involved, retraction, preoperative pain, tear type, and preoperative musclepower on logistic regression analysis. Additionally, positive correlations were seen between good surgical postoperative outcome and postoperative activities of daily living, preoperative pain, postoperative muscle power, preoperative activities of daily living, tear type, preoperative external rotation, preoperative muscle power, number of tendons involved, preoperative pain, and duration of symptoms. CONCLUSION: Ageing was found to be the major factor in progressive degeneration of the rotator cuff, and should be considered the single most important contributing factor in the pathogenesis of rotator cuff tears. In addition, degenerative tendonopathy appeared the primary pathology in rotator cuff tear, preceding hypertrophic spur formation. Rotator cuff tears are therefore unlikely to be initiated by impingement; rather, they develop as an intrinsic degenerative tendonopathy.

Adolescent↗
PubMed2001

SPET imaging of central muscarinic acetylcholine receptors with iodine-123 labelled E-IQNP and Z-IQNP.

1-Azabicyclo[2.2.2]oct-3-yl alpha-hydroxy-alpha-(1-iodo-1-propen-3-yl)-alpha-phenylacetate (IQNP) is a muscarinic acetylcholine receptor (mAChR) antagonist and the racemic ligand contains eight stereoisomers. In a single-photon emission tomography (SPET) study in monkeys we recently confirmed that [123I]E-(R,R)-IQNP ([123I]E-IQNP) is a radioligand with modest selectivity for the M1 and M4 subtypes, whereas [123I]Z-(R,R)-IQNP ([123I]Z-IQNP) is non-subtype selective. In the present SPET study, E- and Z-IQNP were examined in human subjects. SPET examination was performed on three male subjects after i.v. injection of [123I]E-IQNP and in another three after i.v. injection of [123I]Z-IQNP. The binding potential (BP) for [123I]E-IQNP was calculated using several quantitative approaches with the cerebellum as a reference region. High-performance liquid chromatography was used to measure radioligand metabolism in plasma. Following [123I]E-IQNP, the radioactivity was high in the neocortex and striatum, intermediate in the thalamus and low in the pons and cerebellum, which is consistent with the rank order for the regional density of M1 and M4 subtypes in vitro. For all regions, peak equilibrium was identified within the 48-h data acquisition. The simplified reference tissue approach using SPET data from 0 to 48 h was the most reliable in this limited series of subjects. Following injection of [123I]Z-IQNP, radioactivity was high in the neocortex and striatum, intermediate in the thalamus and pons and low in the cerebellum, which is in agreement with the density of M1, M2 and M4 subtypes as measured in vitro. Quantitative analyses provided indirect support for specific M2 binding of Z-IQNP in the cerebellum. The high selectivity of [123I]E-IQNP for M1 and M4 receptors allowed the use of cerebellum as a reference region devoid of specific binding, and may be advantageous for applied clinical studies of M1 and M4 receptors binding in man. [123I]Z-IQNP has potential for exploration of M2 receptor binding in the cerebellum.

Adult↗
PubMed2001

Evaluation of three-dimensional glenoid structure using MRI.

The tilting angle and the shape of the glenoid cavity are considered to relate closely to shoulder stability. They are also important when planning arthroplasty and developing new designs. This study examines the glenoid cavity using 3-dimensional MRI. Forty volunteers (20 men, 20 women; average age 21.4; range 18-35 y) were enrolled in the study. The tilting angles of the glenoid bone were measured in 5 consecutive axial planes perpendicular to the glenoidal long axis. Cross sections were divided into 3 types (concave, flat, convex) according to the shape on each plane. The average tilting angles for the 5 planes from the bottom to the top were 3.3+/-4.1, 1.4+/-3.8. -0.6+/-1.9, -1.4+/-3.3, and -6.2+/-3.3 degrees anteriorly, indicating that the 3-dimensional bony structure of the glenoid was twisted anteriorly to posteriorly. Images on the bottom plane consisted of 82.5 % concave type, 15% flat type and 2.5% convex type, while only 3 cases (7.5%) showed concave at the top plane. The shape of the glenoid cavity is thought to be conducive to glenohumeral motion and stability.

Adolescent↗
PubMed2001

The use of a bioactive skin substitute decreases length of stay for pediatric burn patients.

BACKGROUND: To optimize burn care for children, the authors introduced a protocol incorporating the use of a bioactive skin substitute, TransCyte (Advanced Tissue Sciences, La Jolla, CA). This study was designed to determine whether this management plan was safe, efficacious, and decreased hospital inpatient length of stay (LOS) compared with conventional burn management in children. METHODS: All pediatric burns greater than 7% total body surface area (TBSA) that occurred after October 1999 underwent wound closure with TransCyte (n = 20). These cases were compared with the previous 20 consecutive burn cases greater than 7% TBSA that received standard therapy. Standard therapy consisted of application of antimicrobial ointments and hydrodebridement. The following information was obtained: burn mechanism, age, size of burn, requirement of autograft, and LOS. Data were analyzed using the student's t test. RESULTS: Data for age, percent TBSA burn and LOS are reported as means +/- SEM. The children who received standard therapy were 2.99 +/- 0.7 years compared with those receiving TransCyte were 3.1 +/- 0.8 years. There was no difference between the treatment groups with regard to percent TBSA burn: standard therapy, 14.3 +/- 1.4% TBSA versus TransCyte, 12.7 +/- 1.3% TBSA. There was no difference in the type of burns in each group, the majority were liquid scald type, 70% in the standard therapy group versus 90% in the TransCyte group. Only 1 child in the TransCyte group required autografting (5%) compared with 7 children in the standard therapy group (35%). Children treated with TransCyte had a statistically 6 significant decreaed LOS compared with those receiving standard therapy, 5.9 +/- 0.9 days versus 13.8 +/- 2.2 days, respectively (P =.002). CONCLUSIONS: This is the first study using TransCyte in children. The authors found that this protocol of burn care was safe, effective, and significantly reduced the LOS. This new approach to pediatric burn care is effective and improves the quality of care for children with burns.

Burn Units↗
PubMed2001

The role of radiocarpal injection arthrography and magnetic resonance imaging in the diagnosis of triangular fibrocartilage complex injuries.

OBJECTIVE: To investigate the radiocarpal joint injection arthrography and magnetic resonance imaging for diagnosis of the triangular fibrocartilage complex (TFCC) injuries. METHODS: Thirteen cases whose main complaints were ulnar wrist pain were given radiocarpal joint arthrography and eight of them were also given magnetic resonance imaging for evaluating the integrity of the triangular fibrocartilage complex. RESULTS: Ten of thirteen cases presented the leakage of contrast medium to distal radioulnar joint from the radiocarpal joint, in whom, 8 were demonstrated triangular fibrocartilage tear on magnetic resonance imaging, and 3 located at radial side, 2 at central, 3 at ulnar side. One of three cases which were demonstrated without the leakage of contrast medium in arthrography were displayed with marked TFCC tear on magnetic resonance imaging. CONCLUSIONS: The wrist arthrography can provide a definite diagnosis for triangular fibrocartilage disruption with higher sensitivity. magnetic resonance imaging not only demonstrates the site of triangular fibrocartilage disruption as the same value as wrist arthrography, but also displays the other related bony and soft tissues changes.

Adult↗
PubMed2000

Z-IQNP: a potential radioligand for SPECT imaging of muscarinic acetylcholine receptors in Alzheimer's disease.

RATIONALE: The density of the M2 subtype of muscarinic acetylcholine receptors (mAChR) has been shown to be reduced in the brain of patients with Alzheimer's disease (AD). It is therefore of interest to develop a brain imaging method for diagnostic purposes. Z-(R,R)-1-azabicyclo[2.2.2]oct-3-yl alpha-hydroxy-alpha-(1-iodo1-propen-3-yl)-alpha-phenylacetat e (Z-IQNP) is a muscarinic antagonist with high affinity for the M2 subtype. OBJECTIVE: The pharmacological characteristics and topographic distribution of radiolabelled Z-IQNP as a radioligand for the M2 mAChR subtype were examined in vitro and in vivo. METHODS: Z-IQNP was labelled with 1251 and 123I. Autoradiography was performed on whole-hemisphere cryosections from human post mortem brains. SPECT was performed in a cynomolgus monkey. RESULTS: Autoradiography showed binding of [125I]Z-IQNP in all brain regions, which was inhibited by the non-selective muscarinic antagonist scopolamine. The addition of BIBN 99, a compound with high affinity for the M2 subtype, inhibited [125I]Z-IQNP binding particularly in the cerebellum, which has a high density of the M2 subtype. SPECT demonstrated high uptake of [123I]Z-IQNP in all brain regions. The binding was markedly reduced in all brain regions after pretreatment with the non-selective muscarinic antagonist dexetimide and also the M1 antagonist biperiden. Dexetimide markedly inhibited [123I]Z-IQNP binding in the cerebellum, which is consistent with a high density of M2-receptors in this region. The sigma receptor binding compound DuP 734 had no effect on Z-IQNP binding either in vitro or in vivo. CONCLUSIONS: This study indicates that radiolabelled Z-IQNP has high specificity for mAChR with higher affinity for the M2 than the M1 subtype and negligible affinity for sigma recognition sites both in vitro and in vivo. [123I]Z-IQNP should be useful for future SPECT studies in AD for examination of the density of M2 receptors particularly in the cerebellum.

Alzheimer Disease↗
PubMed1999

Iodine-123 labelled Z-(R,R)-IQNP: a potential radioligand for visualization of M(1 )and M(2) muscarinic acetylcholine receptors in Alzheimer's disease.

Z-(R)-1-Azabicyclo[2.2.2]oct-3-yl (R)-alpha-hydroxy-alpha-(1-iodo-1-propen-3-yl)-alpha-phenylacetate (Z-IQNP) has high affinity to the M(1 )and M(2) muscarinic acetylcholine receptor (mAChR) subtypes according to previous in vitro and in vivo studies in rats. In the present study iodine-123 labelled Z-IQNP was prepared for in vivo single-photon emission tomography (SPET) studies in cynomolgus monkeys. SPET studies with Z-[(123)I]IQNP demonstrated high accumulation in monkey brain (>5% of injected dose at 70 min p.i.) and marked accumulation in brain regions such as the thalamus, the neocortex, the striatum and the cerebellum. Pretreatment with the non-selective mAChR antagonist scopolamine (0.2 mg/kg) inhibited Z-[(123)I]IQNP binding in all these regions. The percentage of unchanged Z-[(123)I]IQNP measured in plasma was less than 10% at 10 min after injection, which may be due to rapid hydrolysis, as has been demonstrated previously with the E-isomer of IQNP. Z-[(123)I]IQNP showed higher uptake in M(2)-rich regions, compared with previously obtained results with E-[(123)I]IQNP. In conclusion, the radioactivity distribution from Z-[(123)I]IQNP in monkey brain indicates that Z-[(123)I]IQNP binds to the M(1)- and M(2)-rich areas and provides a high signal for specific binding, and is thus a potential ligand for mAChR imaging with SPET.

Alzheimer Disease↗
PubMed1994

Effects of joint distention in shoulder diseases.

From 1982 to 1992 arthrography was performed in 3707 patients with painful shoulders to determine the role of the subscapular bursal obliteration in the pathogenesis of painful, stiff shoulders and to evaluate the effects of distention on the subscapular bursa. Three hundred thirty-nine patients were excluded from the study because of incomplete data, leaving 3368. There were 2391 male and 977 female patients; their average age was 39.2 years (range, 8-86 years). Obliteration was noted in 1156 patients (34.3%), and filling of the bursa was seen in 2212 patients (67.7%). Function was regained in 178 patients (5%) by fluid distention alone, and in 308 (8%) patients by additional forced motion. Thus, 486 shoulders (14%) underwent distention and mobilization successfully. The most effective motion was forced abduction and internal rotation. Four hundred fifteen subjects were evaluated clinically; immediate pain relief after distention and/or bursting of the subscapular bursa was noted in all. There was also a remarkable improvement in the range of motion in all subjects who underwent distention alone, or in combination with forced mobilization.

Adolescent↗
PubMed1994

Surgical procedure and results of repair of massive tears of the rotator cuff.

One hundred eighty-seven patients (189 shoulders) were treated surgically between 1970 and 1992 for massive rotator cuff tears using either a tendon-to-tendon repair or the McLaughlin procedure. The age of the patients ranged from 20 to 86 years; 95% of them were 45 years or older. The average followup was 6 years 9 months. Excellent or good functional results were attained in 93% of patients. Thirty-three percent of those who underwent tendon to tendon repair complained of pain after overuse compared with only 18% who had the McLaughlin Procedure.

Adult↗
PubMed1993

[A quantitative pharmaco-EEG study on psychotropic properties of cerebral metabolic enhancers: comparison between young and elderly healthy volunteers].

In order to investigate psychotropic properties of cerebral metabolic enhancers (CMEs), the author carried out two identical quantitative pharmaco-EEG studies in different age groups of healthy volunteers; the young group (group-Y) consisted of six males between the ages of 21-26 years and elderly group (group-E) consisted of six males between the ages of 60-66 years. The drugs tested were five CMEs, dihydroergotoxine mesylate (DHE), propentofylline (PPF), nicergoline (NCG), lisuride maleate (LIS) and ibudilast (IDL). Each volunteer received either of the five test drugs or inert placebo in six one-day weekly sessions' according to single-blind, randomized crossover design. In each session, a single oral dose, equivalent to the clinically recommended daily dose, of either drug or placebo was administered and EEGs were recorded before and 1.3 and 6 hours after the drug administration. Firstly, the background EEGs before the drug administration were compared between the two groups. Group-E showed less slow activities and more alpha and fast activities than group -Y. This difference in background EEG profiles between two groups are considered to be due to physiological aging process. Secondly, drug effects on EEGs in two groups were compared. There were discrepancies in drug-induced EEG changes between the groups. In group-Y, any of the five tested CMEs did not induce EEG changes that were significantly different from placebo, whereas, in group-E, drug-induced EEG changes were more apparent. In group-E, DHE and PPF induced similar EEG changes, which were characterized by a decrease of alpha activity associated with marked decreases of slow and fast activities, the EEG profile similar to thymoleptics with sedative effects. LIS and IDL induced a decrease of alpha activity and an increase of fast activities, the profile close to thymoleptics with mood-elevating (stimulant) effects. NCG induced an increase of slow activities, the profile close to central depressants. These results in this study coincided with the experimental and subjective classification of the clinical effects of CMEs. Further analysis of EEG profiles based on principal component analysis indicated that there were two major components in background EEGs. There were discrepancies in the response to CMEs between two groups. In group-Y, CME-induced changes were seen mainly in the second principal component, while in group-E, the changes were seen mainly in the first principal component. These results suggested CMEs provoked thymoleptic effects by affecting the essential component of the EEG basic rhythm.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Preparation and evaluation of octadecyl-treated porous glasses. Application to the determination of methotrexate in serum.

The retention and selectivity of methotrexate (MTX) in serum were studied by high-performance liquid chromatography on octadecyl-treated porous glasses and silicas. From elemental analysis data for carbon, the maximum number of bonded octadecyl surface groups per gram (mean pore diameter 153 A, specific surface area 193 m2/g, pore volume 0.83 ml/g) in octadecyl-treated glass was calculated to be 0.131 x 10(21). MTX in human serum could be separated on both glasses and silicas with methanol-acetate buffer mixtures as eluents.

Chromatography, High Pressure Liquid↗
PubMed1990

Contracture of the shoulder.

A retrospective study involving 2027 patients with a limited range of motion of the shoulder in the period from 1970 to 1987 is described. Of these, 1219 patients (60%) were diagnosed as having frozen shoulder, with the highest incidence occurring in patients aged 50-60 years. The mechanism involved in the contracture is complicated. At first, the movement of the greater tuberosity at the subacromial level (also called the subacromial secondary joint) is limited due to bursitis. The external rotation of the upper arm then decreases, and the long rotator muscles contract. The relationship between the cause of contracture and the direction of the decreased mobility was analyzed. A ratio of the degree of external rotation with the arm beside the body to that achieved with the arm elevated to the horizontal plane showed values of almost one to one. Conservative treatment including physiotherapy, local anesthetic block, and joint distension must be attempted in all patients. If the conservative treatment remains ineffective, the surgical procedure should be considered. Satisfactory clinical results of arthroplasty of the subacromial joint were obtained in patients with frozen shoulder.

Adolescent↗