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1.
Epidemiol Infect ; 149: e244, 2021 11 02.
Article in English | MEDLINE | ID: mdl-34726137

ABSTRACT

In June 2020, a large-scale food poisoning outbreak involving about 3000 elementary and junior high school students occurred in Yashio, Saitama, Japan. A school lunch was the only food stuff ingested by all of the patients. Escherichia coli serotype O7:H4 carrying the astA gene for enteroaggregative E. coli (EAggEC) heat-stable enterotoxin 1 (EAST1) was detected in faecal specimens from the patients, and sample inspection revealed its presence in a seaweed salad and red seaweed (Gigartina tenella) as one of the raw materials. Analysis of the antibiotic sensitivity of the isolates revealed resistance to ampicillin and cefotaxime. All isolates were confirmed to be of the same origin by pulsed-field gel electrophoresis after digestion with the restriction enzyme XbaI, and single nucleotide polymorphism analysis using whole genome sequencing. To our knowledge, this is the first report of a large-scale food poisoning caused by E. coli O7:H4, which lacks well-characterized virulence genes other than astA.


Subject(s)
Disease Outbreaks , Escherichia coli/isolation & purification , Foodborne Diseases/epidemiology , Foodborne Diseases/microbiology , Bacterial Toxins/genetics , Bacterial Toxins/isolation & purification , DNA, Bacterial/genetics , Drug Resistance, Bacterial , Enterotoxins/genetics , Enterotoxins/isolation & purification , Escherichia coli/genetics , Escherichia coli Infections/epidemiology , Escherichia coli Infections/microbiology , Escherichia coli Proteins/genetics , Escherichia coli Proteins/isolation & purification , Food Contamination , Food Services , Foodborne Diseases/etiology , Humans , Japan/epidemiology , Rhodophyta , Whole Genome Sequencing
2.
Physiol Meas ; 38(4): N81-N92, 2017 04.
Article in English | MEDLINE | ID: mdl-28327472

ABSTRACT

OBJECTIVE: Spatio-temporal parameters are typically used for gait analysis. Although these parameters are measured by sophisticated systems such as 3D motion capture system or optoelectronic bars, these systems cannot be deployed easily because of their high costs, large space requirements and elaborate set-up. The purpose of this study is to develope a system for measuring spatiotemporal gait parameters using a laser range scanner during treadmill gait. APPROACH: To calculate accurate spatiotemporal parameters, the differences between the laser range scanner measured values and the reference values obtained from a 3D motion capture system were investigated in thirty subjects. From measurements in time and position at foot contact/off, adjustments to compensate for the differences in time and position were derived. Then, to determine the validity of the proposed system, values from the proposed system and the reference system were compared in four additional subjects. MAIN RESULTS: The results indicate that the data from the laser range scanner demonstrate certain differences in time and position compared with reference values. However, when compensation values were introduced, each spatiotemporal parameter correlated well with the reference values. SIGNIFICANCE: This newer system is smaller, is easier to deploy and requires less training than the 3D motion capture system.


Subject(s)
Exercise Test/methods , Gait , Healthy Volunteers , Lasers , Spatio-Temporal Analysis , Adult , Exercise Test/instrumentation , Feasibility Studies , Female , Humans , Male , Young Adult
4.
Endoscopy ; 45(2): 98-105, 2013.
Article in English | MEDLINE | ID: mdl-23307149

ABSTRACT

BACKGROUND AND STUDY AIMS: Endocytoscopy enables observation at 450-fold magnification during gastrointestinal endoscopy, allowing on-site "optical biopsy." We compared the accuracies of endocytoscopy and standard biopsy for the diagnosis of colorectal neoplasms. PATIENTS AND METHODS: We performed a randomized, controlled, open-label trial of patients with colorectal lesions (≥ 5 mm) detected during colonoscopy in a tertiary referral center. We randomly assigned the 203 detected lesions of 170 eligible patients to either the endocytoscopy or standard biopsy group. An on-site endoscopist assessed the histopathology of the endocytoscopy group lesions according to the endocytoscopic findings, whereas a pathologist later assessed standard biopsy group lesions by microscopic examination of the biopsy specimens. We calculated the diagnostic accuracies in both groups with reference to the final histopathology of the resected specimens. The primary endpoint was to determine whether the diagnostic accuracy of endocytoscopy for neoplastic lesions was noninferior to that of standard biopsy (with a predefined noninferiority margin of 10%). Analyses were by intention-to-treat and per-protocol. The study is registered, number UMIN000003923. RESULTS: Overall, 102 lesions in the endocytoscopy group and 101 in the standard biopsy group were available for primary outcome analysis. There were no complications. The diagnostic accuracy of endocytoscopy for the discrimination of neoplastic lesions was 94.1% (95% confidence interval 87.6% to 97.8%), whereas that of standard biopsy was 96.0% (90.2% to 98.9%), which is within the noninferiority margin (absolute difference -1.9%, -8.6% to +5.0%). CONCLUSIONS: Endocytoscopy is noninferior to standard biopsy for the discrimination of neoplastic lesions. With its advantage of providing an on-site diagnosis, endocytoscopy could provide a novel alternative to standard biopsy in routine colonoscopy.


Subject(s)
Adenoma/pathology , Colon/pathology , Colonoscopy/methods , Colorectal Neoplasms/pathology , Rectum/pathology , Aged , Biopsy , Colonoscopes , Female , Humans , Intention to Treat Analysis , Male , Microscopy , Middle Aged , Observer Variation , Sensitivity and Specificity
6.
Endoscopy ; 42(7): 541-5, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20593331

ABSTRACT

BACKGROUND AND STUDY AIMS: Video capsule endoscopy has been established in diagnosis of small-bowel disease and has been evaluated for esophageal pathology and recently for colorectal diagnostics. Gastric capsule endoscopy has not hitherto been feasible due to the stomach's large surface area and volume. We present the first application of a magnetically navigated capsule in the human stomach. PATIENTS AND METHODS: 29 volunteers and 24 patients (men 42, women 11; mean age 47.5 years) were included in a feasibility study. Low-level magnetic fields were used to maneuver the double-sensor video capsule within the human stomach with an air-water interface provided by ingestion of 1300 ml water within 1 hour before examination. Visualization of all parts of the stomach was attempted; time for visualization was recorded, and a subjective assessment of completeness of visualization was documented. RESULTS: There was technical failure in one individual; thus technical success rate was 98 %. In the 52 remaining cases, examiners assessed that the antrum, body, fundus, and cardia were fully visualized in 98 %, 96 %, 73 % and 75 %, respectively. Mean duration of examinations was 30 minutes (range 8 - 50), with a longer time (mean 37 minutes) for volunteers for study reasons. In total, 30 findings were identified: 14 were detected by both gastroscopy and capsule, 10 lesions were identified by guided capsule examination only, 6 by gastroscopy only. No significant capsule-related adverse events occurred. CONCLUSION: Magnetically navigated video capsule endoscopy appears to be feasible and sufficiently accurate for gastric examination. It may permit endoscopic examinations that are more patient-friendly and without sedation. Comparative studies are under way.


Subject(s)
Capsule Endoscopy/methods , Stomach Diseases/diagnosis , Adult , Aged , Feasibility Studies , Female , Humans , Magnetics , Male , Middle Aged , Stomach , Young Adult
7.
J Food Prot ; 71(7): 1460-4, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18680947

ABSTRACT

A total of 353 samples of 29 types of seafood were tested for Salmonella prevalence and total microbial population. Salmonella enterica serotype Weltevreden was isolated from 2 of 47 black tiger prawn samples. The contamination levels of Salmonella were in a range of <30 to 40 most probable number per 100 g. In addition, one sample of black tiger prawns and two samples of white shrimp were positive for Salmonella invA gene on PCR assay. Although the mean aerobic bacterial count was greater than 4 log CFU/g in most of the sample types, those in the two Salmonella-isolated samples of black tiger prawn were 7.48 and 5.18 log CFU/g, respectively. These results indicate the possibility that shrimp and prawns contribute to foodborne infections. The improvement of seafood quality is an important issue, and the information on contamination by pathogens should be provided as feedback to the originating country, with the aim of increasing safety.


Subject(s)
Food Contamination/analysis , Salmonella/isolation & purification , Seafood/microbiology , Shellfish/microbiology , Animals , Colony Count, Microbial/methods , Consumer Product Safety , Food Microbiology , Humans , Japan , Prevalence , Salmonella/growth & development , Salmonella enterica/growth & development , Salmonella enterica/isolation & purification
8.
Spinal Cord ; 45(1): 57-63, 2007 Jan.
Article in English | MEDLINE | ID: mdl-16819556

ABSTRACT

STUDY DESIGN: Retrospective study of the degree of gait independence achieved by persons with spinal cord injury (SCI) using knee-ankle-foot orthosis with a medial single hip joint (MSH-KAFO). OBJECTIVE: To examine the effects of the neurological level, degree of paresis, age, and inhibitory physical/other factors on the gait with a MSH-KAFO in patients with SCIs. SETTING: Three university hospitals and two rehabilitation hospitals in Japan. METHODS: The 45 patients (36 men, nine women) examined included 10 with injuries in the cervical cord between C6 and C8 (group C), 20 with injuries in the upper-middle thoracic cord between T4 and T10 (group UT), and 15 with injuries in the lower thoracic-lumbar cord between T12 and L1 (group TL). Mean age was 34.0 years (range 16-68 years). Of these patients, 13 used the Walkabout, four used the gear joint, and 28 used the Primewalk as the medial hip joint. Recursive partitioning, which predicted the final status of gait from the level, degree of paresis, age, and inhibitory factors, was performed, and a decision tree for gait was constructed. Inhibitory factors were spasticity, involuntary spasms or muscle contractions, pain, contracture, weakness of the upper extremities, and decreased motivation to perform gait exercise. The degree of gait independence was rated on the following five-point scale: outdoor independent gait (5 points), indoor independent gait (4 points), indoor supervised gait (3 points), indoor assisted gait (2 points), and gait within parallel bars (1 point). New branches were added to the decision tree for gait based on the clinical experience, thereby constructing a new decision tree. RESULTS: The coincident ratio between the value predicted on the basis of the decision tree of gait and the value actually observed was 53.3%. The coincident ratio between the value predicted on the basis of the modified decision tree of gait and the actually observed value was 68.9%. CONCLUSION: The results provide valuable information to medical teams that may assist prescription of gait orthoses.


Subject(s)
Decision Trees , Gait/physiology , Hip Prosthesis , Orthotic Devices , Spinal Cord Injuries/physiopathology , Spinal Cord Injuries/rehabilitation , Adolescent , Adult , Ankle Joint/physiopathology , Female , Hip Joint/physiopathology , Humans , Lower Extremity , Male , Middle Aged , Neurologic Examination , Physical Therapy Modalities , Postural Balance , Predictive Value of Tests , Retrospective Studies
10.
Int J Hyperthermia ; 21(8): 703-11, 2005 Dec.
Article in English | MEDLINE | ID: mdl-16338852

ABSTRACT

Molecular chaperones, which are mostly heat- or stress-induced proteins (HSPs), not only regulate various cellular functions such as protein folding, refolding of partially denatured proteins, protein transport across membranes, cytoskeletal organization, degradation of disabled proteins, and apoptosis, but also act as cytoprotective factors against deleterious environmental stresses. Recent studies indicated that moderate overexpression of molecular chaperones could confer cells and tissues stress tolerance and provide beneficial effects on various pathological states associated with protein misfolding and protein aggregation. Mild heat shock, transfection of HSP genes, and some chemical compounds are the major means of overexpression of molecular chaperones. In this review, we summarize recent studies of chemical compounds that could induce or enhance the expression of molecular chaperones or HSPs.


Subject(s)
Heat-Shock Proteins/metabolism , Molecular Chaperones/metabolism , Animals , Anti-Inflammatory Agents, Non-Steroidal/metabolism , Anti-Ulcer Agents/metabolism , Arachidonic Acid/metabolism , Heat-Shock Proteins/antagonists & inhibitors , Heat-Shock Proteins/genetics , Humans , Plant Extracts/metabolism , Prostaglandins/metabolism , Proteins/chemistry , Proteins/metabolism , Serine Proteinase Inhibitors/metabolism
12.
J Neurol Neurosurg Psychiatry ; 76(2): 283-5, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15654054

ABSTRACT

We report the case of a 16 year old girl with vertical-torsional oscillations. She had a 4 year history of bilateral horizontal gaze palsy caused by a cavernous angioma in the medial part of the dorsal pons. She presented with vertical oscillopsia that had worsened during the past 3 months. Unilateral three dimensional eye movements and bilateral horizontal eye movements were recorded using a magnetic search coil method and direct current electro-oculography, respectively. She had vertical-torsional oscillations (average frequency: 3.0 Hz) leaving vertical saccades and pursuits intact. The average amplitudes of the vertical and torsional components were 2.0 degrees and 0.6 degrees , respectively. Her horizontal rapid eye movements were severely impaired; however, her horizontal pursuits and slow phases of vestibulo-ocular reflex were only partially impaired (gain<0.3, oculomotor range<+/-9 degrees ). Convergence and divergence were intact. Lesions involving the medial part of the dorsal pons and bilateral paramedian pontine reticular formation can induce vertical and torsional oscillations without disruption of vertical rapid eye movements.


Subject(s)
Brain Stem Neoplasms/complications , Hemangioma, Cavernous, Central Nervous System/complications , Nystagmus, Pathologic/etiology , Pons/pathology , Adolescent , Female , Functional Laterality , Humans , Paralysis/etiology
13.
Diabet Med ; 21(12): 1292-7, 2004 Dec.
Article in English | MEDLINE | ID: mdl-15569131

ABSTRACT

AIMS: To investigate the relationship of aqueous macrophage migration inhibitory factor (MIF) and monocyte chemotactic protein-1 (MCP-1) levels with the clinical stage of diabetic retinopathy. METHODS: We assayed MIF and MCP-1 levels in aqueous humour samples obtained from 40 diabetic patients (49 eyes) and 24 non-diabetic patients (31 eyes) using enzyme-linked immunosorbent assay. According to the clinical stage of diabetic retinopathy, the diabetic patients were classified into non-diabetic retinopathy (11 eyes), non-proliferative diabetic retinopathy (14 eyes) and proliferative diabetic retinopathy (24 eyes). RESULTS: The aqueous levels of MIF (mean +/- sd) were 6.34 +/- 4.53 ng/ml in proliferative diabetic retinopathy, 3.22 +/- 1.71 ng/ml in non proliferative diabetic retinopathy, 1.25 +/- 0.96 ng/ml in non-diabetic retinopathy and 1.07 +/- 0.94 ng/ml in non-diabetic patients. Significant differences were found among these four groups (P < 0.0001). Aqueous MCP-1 levels were 1668.6 +/- 1442.3 pg/ml in proliferative diabetic retinopathy, 1528.6 +/- 1994.6 pg/ml in non-proliferative diabetic retinopathy, 690.2 +/- 402.1 pg/ml in non-diabetic retinopathy and 622.7 +/- 245.3 pg/ml in non-diabetic patients. Significant differences were also found among these four groups (P < 0.0001). After correcting for total aqueous protein, the ratios of MIF and MCP-1 to total protein remained significantly correlated with the clinical stage of diabetic retinopathy (P < 0.0001, P = 0.0004, respectively). The ratios of MIF to total protein significantly correlated with the ratios of MCP-1 to total protein in diabetic patients (r = 0.680, P < 0.0001). CONCLUSIONS: Aqueous MIF levels significantly correlated with aqueous MCP-1 levels and the clinical stage of diabetic retinopathy. The results suggest that MIF has a co-operative role with MCP-1 in the progression of diabetic retinopathy.


Subject(s)
Aqueous Humor/chemistry , Chemokine CCL2/analysis , Diabetic Retinopathy/metabolism , Macrophage Migration-Inhibitory Factors/analysis , Adult , Aged , Aged, 80 and over , Case-Control Studies , Disease Progression , Enzyme-Linked Immunosorbent Assay/methods , Female , Humans , Male , Middle Aged , Retinal Diseases/metabolism , Statistics, Nonparametric , Vitreoretinopathy, Proliferative/metabolism
14.
J Int Med Res ; 32(2): 141-8, 2004.
Article in English | MEDLINE | ID: mdl-15080017

ABSTRACT

Autoantibodies against heat shock protein 40 (HSP40) and their clinical significance in ulcerative colitis (UC) have not been evaluated before. Twenty-six tissue specimens of inflamed areas from patients with UC, 16 from patients with Crohn's disease (CD) and 16 endoscopically normal tissues were analysed for HSP40 expression. Sera from 47 patients with UC and 44 healthy volunteers were examined for the presence of autoantibodies against HSP40 by enzyme-linked immunosorbent assay test. Immunohistochemistry showed that 17 out of 26 specimens from UC patients, one specimen from a CD patient and one normal tissue specimen were positive for HSP40. Most HSP40-positive cells expressed CD68. Higher titres of anti-HSP40 autoantibodies were detected in sera from UC patients compared with healthy volunteers. In patients with inactive disease, those with proctitis or left-sided colitis had higher titres of anti-HSP40 autoantibodies than those with total colitis. Our study suggests that autoimmunity against HSP40 may have a beneficial effect in UC patients by limiting the extent of the disease.


Subject(s)
Autoantibodies/blood , Colitis, Ulcerative/immunology , Heat-Shock Proteins/immunology , Adolescent , Adult , Aged , Female , HSP40 Heat-Shock Proteins , Humans , Male , Middle Aged
15.
Diabetologia ; 46(5): 699-703, 2003 May.
Article in English | MEDLINE | ID: mdl-12743697

ABSTRACT

AIMS/HYPOTHESIS: Formation of epiretinal membranes (ERMs) in the posterior fundus results in progressive deterioration of vision. ERMs have been associated with numerous clinical conditions including proliferative diabetic retinopathy (PDR), but its pathogenic mechanisms are still unknown. This study was conducted to examine whether or not nuclear factor kappa B (NF-kappaB), a transcription factor that can be activated by various pathological conditions, is involved in the formation of ERMs after PDR. METHODS: ERM samples were obtained by vitrectomy from 22 cases with PDR aged 56+/-11 years with 18+/-10 years of diabetes and 15 cases with idiopathic ERM. They were processed for reverse transcription-polymerase chain reaction (RT-PCR) analysis. In addition, 5 ERM samples from PDR patients aged 51+/-16 years with 15+/-6 years of diabetes were processed for immunohistochemical analysis. RESULTS: NF-kappaB mRNA expression levels were higher (20 out of 22 cases vs. 9 out of 15 subjects in idiopathic ERM, p<0.05) in PDR subjects. Immunohistochemical analysis showed NF-kappaB protein expression in all the 5 ERMs derived from PDR patients, and that region was partially double-labelled with interleukin-8 (IL-8) and von Willebrand factor (vWF). CONCLUSIONS/INTERPRETATION: These results suggest a possibility that NF-kappaB is involved in the formation of ERMs after PDR, especially for the development of vascular endothelial cell component.


Subject(s)
Diabetic Retinopathy/metabolism , Epiretinal Membrane/metabolism , NF-kappa B/genetics , Retina/metabolism , Adult , Aged , Diabetic Retinopathy/genetics , Diabetic Retinopathy/pathology , Endothelium, Vascular/metabolism , Endothelium, Vascular/pathology , Epiretinal Membrane/genetics , Gene Expression Regulation , Humans , Middle Aged , RNA, Messenger/genetics , Reverse Transcriptase Polymerase Chain Reaction , Transcription, Genetic
16.
Endoscopy ; 35(2): 181-4, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12561013

ABSTRACT

Although there have been earlier reports on the use of three-dimensional endoscopic systems in the gastrointestinal tract, real-time three-dimensional imaging has not previously been described. This paper presents experience in three cases with a novel endoscopic system for three-dimensional observation in clinical situations. Case 1 was a hyperplastic gastric polyp, the shape of which was considerably enhanced in comparison with two-dimensional endoscopic viewing. Case 2 was an advanced esophageal cancer, in which the sense of depth was improved in the esophagus. Case 3 was a depressed early gastric cancer, the shape of which was also enhanced. Between July 2001 and March 2002, three experienced endoscopists also used this new system in a further 34 patients. A three-dimensional endoscopic environment was visible with the system in all patients, and all of the endoscopists were able to obtain visual information regarding spatial depth. This experience suggests that the three-dimensional video-endoscopic system used here can be of value in gastrointestinal endoscopy.


Subject(s)
Endoscopy, Gastrointestinal , Esophageal Neoplasms/diagnosis , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional , Polyps/diagnosis , Stomach Neoplasms/diagnosis , Endoscopy, Gastrointestinal/methods , Humans , Video Recording
17.
Int J Colorectal Dis ; 17(5): 311-6, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12172924

ABSTRACT

BACKGROUND AND AIMS: Phospholipase A(2) (PLA(2)) participates in the regulation of phospholipid metabolism and biosynthesis of eicosanoids, serum levels of PLA(2) are suggested to reflect the disease activity in patients with ulcerative colitis (UC). We examined the relationship between histological disease activity and serum levels of PLA(2) IIA and also clarified mucosal production sites of PLA(2) IIA by immunohistochemistry. PATIENTS AND METHODS: Serum samples from 44 patients with UC, 125 with Crohn's diseases (CD), and 68 controls were studied. Biopsy specimens of colonic mucosa obtained from 23 patients with UC were used for assessment of histological activity. The histological score was determined active (1) or inactive (0), and the sum of each histological score from ten segments of the large intestine was assessed as disease activity. The levels of PLA(2) IIA in sera were measured by a radioimmunoassay kit using a specific monoclonal antibody; immunohistochemical study was performed using the same monoclonal antibody. RESULTS: The serum PLA(2) IIA levels in patients with UC and CD were significantly higher than those of controls. Serum PLA(2) IIA levels in UC were closely correlated with histological disease activity. Immunohistochemical study showed the production of PLA(2) IIA by the polymorphonuclear cells, macrophages, and colonic epithelial cells. CONCLUSION: Serum PLA(2) IIA is a good candidate for assessing disease activity in UC as one of clinical laboratory tests.


Subject(s)
Colitis, Ulcerative/blood , Phospholipases A/blood , Biomarkers/blood , Colitis, Ulcerative/complications , Crohn Disease/blood , Crohn Disease/complications , Group II Phospholipases A2 , Humans , Immunohistochemistry , Intestinal Mucosa/metabolism , Intestinal Mucosa/pathology , Statistics as Topic
18.
Arch Phys Med Rehabil ; 82(10): 1389-92, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11588742

ABSTRACT

OBJECTIVES: To examine the relationship between the spinal cord injury (SCI) level, age, and car-driving ability in people with tetraplegia and to explore the association between car-driving ability and social activity. DESIGN: Retrospective clinical survey. SETTING: Rehabilitation center in Japan. PATIENTS: Sixty-two subjects with traumatic complete tetraplegia. INTERVENTIONS: Driving evaluation; comprehensive driver's training (muscle strengthening, transfer training, adjustment of equipment, on-road training); and questionnaire (car-driving status, employment, participation in sports). MAIN OUTCOME MEASURES: The SCI level (Zancolli's classification), age, functional status of activities of daily living (ADLs), and driving ability were obtained from the medical records. Vocational status and engagement in sports activities were investigated by questionnaire. RESULTS: The SCI level and age strongly influenced the patients' ability to drive a car independently. The highest neurologic level in which independent driving was achievable was C6A. Toilet transfer ability almost paralleled the ability to drive a car. Eighty-four percent of the people with tetraplegia who had a defined job could drive independently and 70% of the driving-independent individuals held a job. Half of driving-independent individuals participated in some sports activities. CONCLUSIONS: Toilet transfer ability is a reliable indicator for driver's training. Driving ability is an important factor that allows individuals with tetraplegia to participate in work and sports-related activities.


Subject(s)
Automobile Driving , Quadriplegia/rehabilitation , Spinal Cord Injuries/rehabilitation , Activities of Daily Living , Adolescent , Adult , Aged , Female , Humans , Male , Middle Aged , Quadriplegia/etiology , Quadriplegia/physiopathology , Retrospective Studies , Spinal Cord Injuries/complications , Spinal Cord Injuries/physiopathology , Sports , Work
19.
Jpn J Ophthalmol ; 45(5): 475-81, 2001.
Article in English | MEDLINE | ID: mdl-11583668

ABSTRACT

PURPOSE: To determine whether visual inputs from the tectothalamocortical pathway influence three-dimensional motion processing within the lateral suprasylvian (LS) area of the cat. METHODS: Tungsten microelectrodes were used for recording visual-evoked potentials (VEPs) from the LS area of 4 cats. Random dot stereograms were used as visual stimuli. Three-dimensional, motion-triggered VEPs were recorded from the LS area. Each motion sequence consisted of an abrupt onset of motion disparity with a 2 degrees amplitude followed by an abrupt offset and a stationary phase of 900 ms. The velocity of the motion disparity was varied in eight steps from 10 degrees to 400 degrees per second. The onset of motion disparity was used as the trigger for recording the VEPs. Single or multiple injections (two to three) of muscimol were made mainly into the rostral superior colliculus (SC). The amplitudes of the VEPs before and after the muscimol injection were compared. RESULTS: A large negative wave ( N1) with an implicit time of 92.7 +/- 13.5 ms (mean +/- SD, n = 98) was recorded consistently. The amplitude of N1 was significantly larger on stereovision of motion disparity than on either binocular vision of two-dimensional lateral motion or monocular vision, indicating that N1 contains neurons sensitive to motion disparity. The amplitude of N1 was not altered by muscimol injection into the SC at velocities < or =50 degrees/s. On the other hand, the amplitude of N1 was reduced to 66-71% of that observed before muscimol injection at velocities > or =75 degrees/s. CONCLUSIONS: These findings suggest that the LS area processes three-dimensional motion inputs via two parallel pathways, the geniculostriate pathway and the tectothalamocortical pathway, at velocities of motion disparity > or =75 degrees/s, while the three-dimensional motion inputs project to the LS area only via the geniculostriate pathway at velocities of motion disparity < or = 50 degrees/s.


Subject(s)
Evoked Potentials, Visual/physiology , Motion Perception/physiology , Posterior Thalamic Nuclei/physiology , Superior Colliculi/physiology , Animals , Cats , GABA Agonists/pharmacology , Muscimol/pharmacology , Retina/physiology , Superior Colliculi/drug effects , Vision Disparity/physiology , Visual Cortex/physiology , Visual Pathways/physiology
20.
Jpn J Ophthalmol ; 45(5): 437-44, 2001.
Article in English | MEDLINE | ID: mdl-11583663

ABSTRACT

PURPOSE: To clarify differences in the dynamics of convergence eye movements in response to symmetrical stimuli between the dominant eye and the nondominant eye under natural viewing conditions. METHODS: This study was conducted in 11 normal volunteers (age range, 22-30 years). The subject was seated on a chair, and the head was fixed using a bite-block. The dominant eye was determined with the "hole-in-the-card" test. Horizontal positions of the eyes were recorded using an infrared reflection device. Recordings of right eye movements were subtracted from left eye movements to obtain the vergence response. The fixation target was moved toward the center of both eyes from 50 to 20 cm in front of the face at a constant velocity in five steps (20, 30, 40, 50, and 60 cm/s). The target was moved by a pulse motor controlled by a microcomputer. The dynamic properties of each eye movement and the vergence components were analyzed. RESULTS: At velocities < or =40 cm/s, convergence responses consisted of two components: the fusion-initiating component and the fusion-sustaining component. The fusion-initiating component drove the initial faster dynamic portion of the response, and the fusion-sustaining component maintained the latter slower dynamic portion of the response. The mean peak velocity of the fusion-initiating component was significantly greater in the dominant eye than in the nondominant eye. The mean peak latency of the catch-up component was significantly shorter in the dominant eye than in the nondominant eye. CONCLUSIONS: The present study indicated that the trajectory of convergence eye movement under natural viewing conditions consists of two components, the fusion-initiating component and the fusion-sustaining component, and that the convergence response to symmetric stimuli was asymmetric between the dominant eye and the nondominant eye during the fusion-initiating phase. The neural control system of convergence eye movements preferentially drives the dominant eye during the fusion-initiating phase of the response.


Subject(s)
Convergence, Ocular/physiology , Eye Movements/physiology , Accommodation, Ocular/physiology , Adult , Dominance, Ocular/physiology , Female , Humans , Male
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