Endoscopic evaluation for cytomegalovirus enterocolitis after allogeneic haematopoietic stem cell transplantation.
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Adolescent↗
Biomedical subjects
I Oda
Publications and source records attributed to I Oda.
Cortical mapping of gait in humans: a near-infrared spectroscopic topography study.
While we have a fair understanding of how and where forelimb-hand manipulative movements are controlled by the neocortex, due to functional imaging studies, we know little about the control of bipedal movements such as walking because of technical difficulties. We succeeded in visualizing cortical activation patterns of human gait by measuring relative changes in local hemoglobin oxygenation using a recently developed near-infrared spectroscopic (NIRS) topography technique. Walking activities were bilaterally associated with increased levels of oxygenated and total hemoglobin in the medial primary sensorimotor cortices and the supplementary motor areas. Alternating foot movements activated similar but less broad regions. Gait imagery increased activities caudally located in the supplementary motor areas. These findings provide new insight into cortical control of human locomotion. NIRS topography might be also useful for evaluating cerebral activation patterns during pathological gait and rehabilitative intervention.
Adult↗
Hremx, the ascidian homologue of ems/emx, is expressed in the anterior and posterior-lateral epidermis but not in the central nervous system during embryogenesis.
Recent comparative studies on expression patterns of homeobox genes in the development between ascidians and vertebrates have come to suggest a possibility that a common basic mechanism may exist in the patterning of the central nervous system (CNS). The ems/emx genes have been demonstrated to be involved in the formation and patterning of the anterior CNS in Drosophila and vertebrate embryos. In the present study, we have isolated and analyzed expression of Hremx, the ascidian homologue of ems/emx with particular attention to whether it is expressed in the larval ascidian CNS. Expression of Hremx was detected in the anterior trunk and lateral tail epidermis but not in the anterior CNS. The two expression domains of the epidermis responded in different ways upon treatment with retinoic acid: the anterior expression domain was unaltered, while the posterior expression domain extended to the anterior. The present result suggests that Hremx may have a function in anterior patterning but not in the patterning of the CNS in the ascidian embryo. We suggest the possibility that the function of ems/emx genes in the patterning of the anterior CNS in Drosophila and vertebrate embryos might have been acquired independently in the lineages to Drosophila and vertebrates.
Amino Acid Sequence↗
Variation of temporal characteristics in human cerebral hemodynamic responses to electric median nerve stimulation: a near-infrared spectroscopic study.
Using near-infrared spectroscopy, we studied cerebral hemodynamic responses to electric median nerve stimulation in ten subjects. The recordings were conducted by optical fibers placed over the left scalp. Electric stimuli were delivered to contra- and ipsilateral median nerves, respectively. Hemodynamic responses in the secondary somatosensory cortex were observed following each median nerve stimulation, except for three drowsy subjects. The contralateral stimulation tended to induce a larger response. The degree of change in oxygenated hemoglobin was hardly related to stimulus intensities, and was augmented by attention. Four subjects showed long-lasting responses throughout the stimulus periods, while three other subjects revealed transient responses. Thus, taking account of the temporal activation patterns is necessary for proper interpretation of the hemodynamic response following electric nerve stimulation.
Adult↗
Endoscopically demonstrable esophageal changes after Helicobacter pylori eradication in patients with gastric disease.
BACKGROUND AND AIMS: An increased prevalence of reflux esophagitis has been reported following Helicobacter pylori (H. pylori) eradication in patients with duodenal ulcers in Western countries. However, it has remained unknown whether this might also appertain to individuals with other diseases. We therefore carried out this study to determine the effect of eradicating H. pylori infection in a series of Japanese patients. METHODS: Of a total of 203 H. pylori-positive patients successfully cured of infection, 82 cases (58 males, 24 females) with gastric disease, but not duodenal ulcers, were included in the present study; median age 56 years (range 18-80) and median follow up of 24 months (range 6-65). The patients were investigated clinically and endoscopically at regular intervals. RESULTS: Mild reflux esophagitis developed after eradication in three of 55 (5.5%) patients formerly without this condition, while it improved after eradication in five of 27 (18.5%) patients, with the disease endoscopically diagnosed prior to eradication. The estimated incidence of esophagitis within 3 years was 4.8% after cure of infection. Short segment Barrett's esophagus developed after eradication in six of 58 (10.3%) patients who did not have it prior to the therapy, while the condition did not improve in 24 patients affected before eradication. CONCLUSIONS: Endoscopic esophageal changes after H. pylori eradication in the present series of Japanese patients were relatively infrequent and mild. This therapeutic approach thus appears to be safe and unproblematic.
Adolescent↗
[Treatment of gastric MALT lymphoma by H. pylori eradication].
Strong evidence exists for the efficacy of H. pylori eradication in achieving gastric low-grade MALT lymphoma (L-MALT) regression when the bacteria present. Besides histological evaluation, the appearance of endoscopic finding such as 'discolored mucosa-like atrophy' after treatment may be useful for the prediction of its outcome (endoscopic evaluation). However, a reliable marker for molecular evaluation is not obtained so far. On the other hand, long-term control of L-MALT with H. pylori eradication therapy is uncertain and there still remains a subset of patients with no evidence of H. pylori or who fail H. pylori eradication therapy. Therefore, the optimal non antibiotic therapy for these patients has been studied. According to the recent report, radiation therapy appears to be well tolerated and effective for patients with gastric L-MALT.
Combined Modality Therapy↗
Anterior vertebral screw strain with and without solid interspace support.
STUDY DESIGN: This in vitro biomechanical study examines segmental anterior vertebral screw strain and solid rod construct stiffness with and without the addition of multilevel, threaded cortical bone dowels in a bovine model. OBJECTIVE: To determine whether strain at the bone-screw interface is higher at the end levels during physiologic range loading, and whether solid interspace support decreases segmental strain on the implant. SUMMARY OF BACKGROUND DATA: Anterior instrumentation provides greater correction and preserves distal motion segments. However, nonunion and implant failure are observed more frequently than with posterior segmental instrumentation, and when observed, loss of fixation occurs at the end levels. METHODS: Eight calf spines underwent mechanical testing in the following sequence: 1) intact condition, 2) anterior release with anterior solid rod and bicortical rib grafts, and 3) anterior release with anterior solid rod and threaded cortical bone dowels (L2-L5). Instrumented vertebral screws were used to assess strain within the vertebral body by the near cortex, whereas an anterior extensometer spanning the instrumented segments was used to measure segmental displacements to calculate construct stiffness. The protocol included axial compression (-400 N), right lateral bending (4 Nm (Newton-meter), away from the implant), and left lateral bending (4 Nm, toward the implant). Statistical analysis included a one-way analysis of variance and a Student-Newman-Keuls post hoc test. A pilot study was performed using four additional specimens loaded for 4000 cycles to investigate macroscopic loosening after fatigue loading. RESULTS: In lateral bending toward the implant, the strain was higher at both end levels, with no differences between the rib and dowel reconstructions. The stiffness values were greater than the intact values for both groups. In lateral bending away from the implant, the strain also was higher at both end screws, and the dowel group had less strain at these levels than the rib group. Both groups were stiffer than the intact condition, and the dowel group was stiffer than the rib group. Axial compressive strain also was higher at the end levels, but this difference did not reach statistical significance. The rib group did not reach intact stiffness values, whereas the dowel group was stiffer than the intact condition. The fatigue study showed gross loosening at one or both end levels in all cases. CONCLUSIONS: Higher strain was observed at the bone-screw interface in both end screws of an anterior solid rod construct during lateral bending, which correlates with the clinically observed failure location. This suggests that physiologic range loading may predispose to failure at the end levels. Disc space augmentation with solid implants increased construct stiffness in all three load paths and decreased strain at the end levels in lateral bending away from the implant. Future implant modifications should achieve better fixation at the end screws, and the current model provides a means to compare different strategies to decrease strain at these levels.
Animals↗
Biomechanical properties of anterior thoracolumbar multisegmental fixation: an analysis of construct stiffness and screw-rod strain.
STUDY DESIGN: Three types of anterior thoracolumbar multisegmental fixation were biomechanically compared in construct stiffness and rod-screw strain. OBJECTIVES: To investigate the effects of rod diameter and rod number on construct stiffness and rod-screw strain in anterior thoracolumbar multisegmental instrumentation. SUMMARY OF BACKGROUND DATA: No studies have been undertaken to investigate the biomechanical effects of rod diameter and rod number in thoracolumbar anterior instrumentation. METHODS: Ten fresh-frozen calf spines (T13-L5) were used. After intact analysis, a total discectomy and transection of the ALL and PLL were performed at L1-L2, L2-L3, and L3-L4 with intervertebral reconstruction using carbon fiber cages. Three types of anterior fixation were then performed at L1-L4: 1) 4.75-mm diameter single-rod, 2) 4.75-mm dual-rod, and 3) 6.35-mm single-rod systems. Single screws at each vertebra were used for single-rod and two screws for dual-rod fixation. These systems share the same basic design except rod diameter. Nondestructive biomechanical testing was performed and included compression, torsion, flexion-extension, and lateral bending. Construct stiffness and rod-screw strain of the three reconstructions were compared. RESULTS: The 6.35-mm single-rod fixation significantly improved construct stiffness compared with the 4.75-mm single rod fixation only under torsion (P < 0.05). The 4. 75-mm dual rod construct resulted in significantly higher stiffness than did both single-rod fixations (P < 0.05), except under compression. No statistical differences were observed in rod-screw strain between the two types of single rods, whereas dual-rod reconstruction exhibited less rod-screw strain (P < 0.05). CONCLUSIONS: For single-rod fixation, increased rod diameter neither markedly improved construct stiffness nor affected rod-screw strain, indicating the limitations of a single-rod system. In thoracolumbar anterior multisegmental instrumentation, the dual-rod fixation provides higher construct stiffness and less rod-screw strain compared with single-rod fixation.
Animals↗
The effect of kyphosis on the mechanical strength of a long-segment posterior construct using a synthetic model.
STUDY DESIGN: This experimental study used synthetic spine models to compare the effect of the angle of kyphosis, rod diameter, and hook number on the biomechanical stiffness of a long-segment posterior spinal construct. OBJECTIVE: To examine the biomechanical effects of incremental kyphosis on variously instrumented long-segment posterior spinal constructs. SUMMARY OF BACKGROUND DATA: Euler's formula for loading of curved long columns would suggest that kyphosis has a profound impact on the biomechanical behavior of long-segment posterior spinal constructs. The effects of sagittal contour on the mechanical properties of long-segment posterior spinal constructs have not been well documented. METHODS: Kyphotic and straight synthetic spine models were used to test long-segment posterior instrumentation constructs biomechanically while varying rod diameter and the number of hook sites. The synthetic spines, composed of polypropylene vertebral blocks and isoprene elastomer intervertebral spacers, were fabricated with either 0 degrees, 27 degrees, or 53 degrees of sagittal contour. The models were instrumented with 5.5- or 6.35-mm titanium rods, and with either 8 or 12 hooks. The models were loaded from 0 to 300 N in a cyclical ramp fashion using an MTS 858 Bionix testing device testing device. Construct stiffness (force and displacement) during axial compression was determined. RESULTS: Straight model: Changing the hook number from 8 to 12 caused a 32% increase in construct stiffness with the 5.5-mm rod. Changing the rod diameter from 5.5 to 6.35 mm caused a 36% increase in construct stiffness with the 8-hook pattern. Changing both the rods and hooks caused the stiffness to increase 44%. 27 degrees MODEL: Changing the hook number from 8 to 12 caused a 20% increase in construct stiffness with the 6.5-mm rod. Changing the rod diameter from 5.5 to 6.35 mm caused a 29% increase in construct stiffness with the 12-hook pattern. Changing both the rods and hooks caused the construct stiffness to increase 26%. 53 degrees MODEL: Changing the hook number from 8 to 12 caused a 14% increase in construct stiffness with the 6.35-mm rod. Changing the rod diameter from 5.5 to 6.35 mm caused a 17% (P<0.0005) increase in construct stiffness with the 12-hookpattern. Changing both rods and hooks caused the stiffness to increase 21%. Summary data on angular kyphosis: Using the same rod diameter and the same number of hooks, and progressing from a straight alignment to 27 degrees of sagittal contour decreased construct stiffness 32%. Going from straight alignment to 53 degrees decreased the stiffness 59.6%. All reported values were statistically significant (P < 0.0005). CONCLUSIONS: The biomechanical stiffness of the straight spine was sensitive to both an increase in hook fixation sites and an increase in rod diameter. The kyphotic spines, however, were more sensitive to variations in rod diameter. Although with increasing kyphosis, the optimum instrumentation strategy will maximize both rod diameter and the number of hook sites, instrumented kyphotic spines remain biomechanically "disadvantaged" as compared with nonkyphotic instrumented spines.
Bone Nails↗
Visuospatial imagery is a fruitful strategy for the digit span backward task: a study with near-infrared optical tomography.
Our newly developed 64-channel time-resolved optical tomographic imaging system using near-infrared light enables us to obtain a quantitative image of hemoglobin concentration changes associated with neuronal activation in the human brain ¿H. Eda, I. Oda, Y. Ito, Y. Wada, Y. Oikawa, Y. Tsunazawa, M. Takada, Y. Tsuchiya, Y. Yamashita, M. Oda, A. Sassaroll, Y. Yamada, M. Tamura, Multi-channel time-resolved optical tomographic imaging system, Rev. Sci. Instrum., 70 (1999) 3595-3602. Here, we used this optical imaging system to demonstrate that the backward digit span (DB) task activated the dorsolateral prefrontal cortex (DLPFC) of each hemisphere more than the forward digit span (DF) task in healthy adult volunteers, and higher performance of the DB task was closely related to the activation of the right DLPFC. These results suggest that visuospatial imagery is a useful strategy for the DB task. Optical tomography described here is a new modality of neuropsychological studies.
Adult↗
The biomechanical significance of anterior column support in a simulated single-level spinal fusion.
This study examines the biomechanical effects of interbody cages and variations in posterior rod diameter in a simulated single-level spinal fusion. A single-level spinal fusion model composed of polyethylene cylinders, posterior pedicular instrumentation, and variously positioned single or dual interbody cages was used for biomechanical testing. Constructs were tested under compressive flexural load, with measurement of stiffness, rod strain, cage strain, and intracage pressure. A strong linear correlation emerged between the mean construct stiffness and cage positioning within the sagittal plane that was inversely related to posterior rod strain. Two small titanium mesh cages were equivalent to one large cage. In a single-level spine model, the presence of and sagittal position of interbody cages significantly influences overall construct stiffness. Cage strain increased with more anterior positions and was inversely related to rod strain.
Humans↗
[Spontaneous internal drainage of pancreatic pseudocyst with fistula to the common bile duct].
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Aged↗
Usefulness of indigo carmine chromoendoscopy and endoscopic clipping for accurate preoperative assessment of proximal gastric cancer.
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Aged↗
Biomechanical evaluation of five different occipito-atlanto-axial fixation techniques.
STUDY DESIGN: The stabilizing effects of five different occipitocervical fixations were compared. OBJECTIVES: To evaluate the construct stability provided by five different occipito-atlanto-axial fixation techniques. SUMMARY OF BACKGROUND DATA: Few studies have addressed occipitocervical reconstruction stability and no studies to data have investigated anterior-posterior translational stiffness. METHODS: A total of 21 human cadaveric spines were used. After testing intact spines (CO-C2), a type II dens fracture was created and five different reconstructions were performed: 1) occipital and sublaminar wiring/rectangular rod, 2) occipital screws and C2 lamina claw hooks/rod, 3) occipital screws, foramen magnum screws, and C1-C2 transarticular screws/rod, 4) occipital screws and C1-C2 transarticular screws/Y-plate, and 5) occipital screws and C2 pedicle screws/rod. Biomechanical testing parameters included axial rotation, flexion/extension, lateral bending, and anterior-posterior translation. RESULTS: Pedicle screw fixation demonstrated the highest stiffness among the five reconstructions (P < 0.05). The two types of transarticular screw methods provided greater stability than hook or wiring reconstructions (P < 0.05). The C2 claw hook technique resulted in greater stability than sublaminar wiring fixation in anterior-posterior translation (P < 0.05). However, the wiring procedure did not significantly increase the stiffness levels beyond the intact condition under anterior-posterior translation and lateral bending (P > 0.05). DISCUSSION: C2 transpedicular and C1-C2 transarticular screws significantly increased the stabilizing effect compared to sublaminar wiring and lamina hooks. The improved stability afforded by C2 pedicular and C1-C2 transarticular screws offer many potential advantages including a high rate of bony union, early ambulation, and easy nursing care. CONCLUSION: Occipitocervical reconstruction techniques using C1-C2 transarticular screws or C2 pedicle screws offer biomechanical advantages compared to sublaminar wiring or lamina hooks. Pedicle screw fixation exhibited the highest construct stiffness among the five reconstructions.
Aged↗
Does spinal kyphotic deformity influence the biomechanical characteristics of the adjacent motion segments? An in vivo animal model.
STUDY DESIGN: In an in vivo sheep model, the effects of spinal fusion and kyphotic deformity on the neighboring motion segments were analyzed. OBJECTIVES: To investigate the effects of spinal fusion and kyphotic deformity on the adjacent motion segment. SUMMARY OF BACKGROUND DATA: The in vivo effects of kyphotic deformity on the neighboring motion segments have not been investigated in any studies. METHODS: Eighteen sheep were equally randomized into three groups based on surgical procedure: L3-L5 in situ posterolateral fusion (n = 6) L3-L5 kyphotic posterolateral fusion (n = 6), and surgical exposure alone (n = 6). After a 16-week survival period, the adjacent motion segment changes were analyzed radiographically, biomechanically, and histologically. RESULTS: The kyphosis group showed 5.0 degrees +/- 2.6 degrees and 1.7 degrees +/- 1.8 degrees compensatory hyperlordosis at L2-L3 and L5-L6, respectively, compared with surgical exposure and in situ posterolateral fusion, the kyphotic posterolateral fusion significantly influenced cranial adjacent motion segment biomechanics by inducing more stiffness in the posterior ligamentous complex (P < 0.05) and increasing lamina strain under flexion-extension loading (P < 0.05). Results of histologic analysis showed significant degenerative changes of the L2-L3 facet joints in the kyphosis group. CONCLUSIONS: It is inferred that in the kyphosis group, compensatory hyperlordosis at the cranial adjacent level leads to lordotic contracture of the posterior ligamentous complex. The increased lamina strain, exhibited by the in situ group under flexion-extension, was further increased in the kyphosis group, indicating higher load transmission through the posterior column. Significant degenerative changes of the cephalad adjacent facet joints observed in the kyphosis group served to corroborate the biomechanical data. These results indicate that a kyphotic deformity may lead to facet joint contracture and facet arthritis and may serve as the origin of low back pain at the cranial adjacent level.
Animals↗
The stability of reconstruction methods after thoracolumbar total spondylectomy. An in vitro investigation.
STUDY DESIGN: After total spondylectomy, five types of spinal reconstruction techniques were compared biomechanically. OBJECTIVES: To evaluate the stability provided by five reconstruction methods after total spondylectomy. SUMMARY OF BACKGROUND DATA: Total spondylectomy presents a worst-case scenario for spinal reconstruction. However, few investigators have biomechanically investigated spinal reconstruction stability after total spondylectomy. METHODS: Eight human cadaveric spines (T11-L5) were used. After intact analysis, a total spondylectomy was performed at L2 and reconstructed using Harms titanium mesh (Depuy-Motech, Warsaw, IN) as an anterior strut. Anterior, posterior, or circumferential instrumentation techniques were then performed using the Kaneda SR and ISOLA pedicle screw systems (AcroMed Corp., Cleveland, OH) as follows: 1) anterior instrumentation at L1-L3 with multisegmental posterior instrumentation at T12-L4 (AMP), 2) anterior instrumentation at L1-L3 with short posterior instrumentation at L1-L3 (ASP), 3) anterior instrumentation at L1-L3 (A), 4) multilevel posterior instrumentation at T12-L4 (MP), and 5) short posterior instrumentation at L1-L3 (SP). Nondestructive biomechanical testing was performed under axial compression, flexion-extension, and lateral bending loading modes. RESULTS: Only circumferential instrumentation techniques (AMP, ASP) exhibited higher stiffness than the intact spine in all loading modes (P < 0.05). Short circumferential fixation provided more stability than did multilevel posterior instrumentation (P < 0.05). Multilevel posterior fixation provided more stiffness than did short posterior and anterior instrumentation alone (P < 0.05). CONCLUSIONS: Only circumferential fixation techniques provide more stability than the intact spine in all testing modes. Short circumferential instrumentation provides more stability than multilevel posterior instrumentation alone and requires fewer levels of spinal fusion.
Aged↗
Biomechanical role of the intervertebral disc and costovertebral joint in stability of the thoracic spine. A canine model study.
STUDY DESIGN: Biomechanical evaluation was performed to investigate the stability of the thoracic spine. Unilateral resection of the intervertebral disc, the rib head joint, and the costotransverse joint were sequentially performed, and nondestructive cyclic loading tests were conducted at each injury stage to examine the roles of the intervertebral disc and the costovertebral joint of the thoracic spine. The effects of each resection were three-dimensionally analyzed as the main motion and the associated coupled motions. OBJECTIVE: To examine the role of the intervertebral disc and the costovertebral joint in stability of the thoracic spine. SUMMARY OF BACKGROUND DATA: The effects of unilateral resection of the intervertebral disc and the costovertebral joints in the thoracic spine with the rib cage have not been documented three-dimensionally in a biomechanical study. MATERIALS AND METHODS: Ten canine rib cage-thoracic spine complexes, consisting of the sixth to eighth ribs, the sternum and T5-T8 vertebrae, were used. Six pure moments along three axes, flexion-extension, lateral bending, and axial rotation, were applied to the specimen, and the angular deformation between T6-T7 was recorded by a stereophotogrammetric method. After the intact specimens were tested, staged resections were conducted in the following manner: partial resection of the T6-T7 intervertebral disc, performed as a resection of the anterior longitudinal ligament, the nucleus pulposus, and the annulus fibrosus on the approach side, leaving the posterior longitudinal ligament intact; resection of the right seventh rib head with the joint capsule; and resection of the right seventh costotransverse joint. At each stage, the main motion and associated coupled motions were determined three dimensionally. RESULTS: The ranges of motion (ROM) in flexion-extension, lateral bending, and axial rotation were significantly increased after partial discectomy (P < 0.01). Moreover, along with large increases in the ROM of the main motions in left axial rotation and right lateral bending, coupled motions, expressed by right lateral bending and left axial rotation, showed marked increases after resection of the rib head joint (P < 0.05). The neutral zones also increased in lateral bending, axial rotation, and flexion-extension after partial discectomy (P < 0.01). A further increase in the neutral zone was observed in lateral bending after resection of the right seventh rib head (P < 0.01). CONCLUSIONS: In this canine spine model, the intervertebral disc regulates the stability of the thoracic spine in flexion-extension, lateral bending, and axial rotation. Moreover, the articulation of the rib head with the vertebral bodies provides stability to the thoracic spine in lateral bending and axial rotation. Unilateral resection of the rib head joint after partial discectomy on the same side produces significant coupled motions in lateral bending and axial rotation, resulting in a significant decrease in thoracic spinal stability, and integrity.
Animals↗
[An autopsy case of primary non-Hodgkin lymphoma of the extrahepatic bile duct].
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Bile Duct Neoplasms↗