Neurological picture. A case of brain embolism during catheter embolisation of head arteriovenous malformation. What is the mechanism of stroke?
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Catheterization↗
Biomedical subjects
Y Iguchi
Publications and source records attributed to Y Iguchi.
Ischaemic stroke with malignancy may often be caused by paradoxical embolism.
BACKGROUND: Although ischaemic stroke with malignancy occasionally occurs, the mechanisms of stroke in such cases have not been investigated in detail. OBJECTIVE: To examine the mechanisms of ischaemic stroke with malignancy, particularly in relation to right-to-left shunt (RLS). METHODS: Consecutive patients with ischaemic stroke within 24 h of stroke onset were prospectively studied. Contrast saline transcranial Doppler examination was carried out for all patients, to investigate the presence of RLS. When patients with stroke had RLS, deep venous thrombosis (DVT) or pulmonary embolism was assessed to diagnose paradoxical brain embolism. RESULTS: Participants comprised 184 consecutive patients (115 men and 69 women) with a mean (standard deviation (SD)) age of 73 (11.8) years and mean (SD) National Institutes of Health Stroke Scale (NIHSS) score of 8 (7.4). RLS was detected in 32 of 184 (18%) patients. Malignancy was present in 11 (5%) patients. RLS was more frequent in patients with malignancy than in patients without malignancy (55% v 15%, respectively; p = 0.001). All six patients with RLS and malignancy displayed DVT or pulmonary embolism with severe disability (modified Rankin Scale 4-5) before stroke onset. CONCLUSION: Paradoxical brain embolism should be considered to be an important mechanism in patients with stroke and malignancy.
Aged↗
Seasonal variations of acute massive submacular haemorrhage associated with age-related macular degeneration.
AIMS: To determine whether there is a seasonal variation in the onset of acute, massive submacular haemorrhage associated with age-related macular degeneration. METHODS: Sixty eyes of 59 patients diagnosed between April 1998 and March 2005, were studied retrospectively. For each patient, the month and season of onset of the submacular haemorrhage and the mean monthly ambient temperature in Nagoya were analysed. Any history of systemic hypertension was also recorded, and the seasonal variations were also investigated in hypertensive and non-hypertensive groups. RESULTS: The number of cases peaked in winter with a trough in summer, and this seasonal variation was significant (Roger's R = 12.03, p<0.01). The monthly incidence was inversely correlated with the temperature (Spearman's rank correlation coefficient r = 0.89, p<0.01). The seasonal variations were significant in the hypertensive group but not in the non-hypertensive group. CONCLUSION: The considerable seasonal variations suggests that the mechanism for the haemorrhage is strongly correlated with the systemic blood pressure.
Acute Disease↗
Confocal endomicroscopy for the diagnosis of gastric cancer in vivo.
BACKGROUND AND STUDY AIMS: Advances in endoscopy have led to imaging of the details of the gastric mucosa, but the histological diagnosis usually has to be confirmed by endoscopic biopsy. A method of confocal endomicroscopy that has recently been developed allows the observation of living cells in vivo. Several investigators have reported that the technique is of value, but there have as yet been no studies describing its application in gastric cancer. PATIENTS AND METHODS: Twenty-seven patients with early gastric cancer underwent confocal endomicroscopy (Pentax EG-3870CIK; Pentax, Tokyo, Japan). After intravenous administration of fluorescein sodium, confocal images obtained from the normal mucosa and from cancerous lesions were interpreted by two pathologists independently and compared with the histological findings, including CD34 immunostaining of biopsy specimens or resected specimens from the same sites. RESULTS: Fluorescein yielded high-quality confocal images of the gastric mucosa; if cancer could be targeted (59%) images were mostly graded good. The images corresponded to the hematoxylin-eosin staining of transverse sections of specimens from the same sites. In the results for the interpretation by the two pathologists, the accuracy for the diagnosis of gastric cancer was 94.2% (pathologist A), and 96.2% (pathologist B), respectively. The accuracy decreased substantially when poor images and inaccessible lesions were included. CONCLUSIONS: Confocal endomicroscopy is useful in the diagnosis of gastric cancer but good quality images cannot always be obtained. In the future, it may allow virtual biopsy and help reduce unnecessary biopsies.
Adenocarcinoma↗
Dysarthria-clumsy hand syndrome originating in the corona radiata.
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Cerebral Infarction↗
Acute confusional state caused by a large number of small brain infarcts.
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Aged↗
Spiral terraces and spin frustration in layered antiferromagnetic Cr(001) films.
We have successfully fabricated a novel type of high-density spiral terraces on Cr(001) films. The influence of nanoscale spiral terraces on layered antiferromagnetic ordering of Cr(001) films has been studied at room temperature by direct imaging of both topographic and magnetic structures using spin-polarized scanning tunneling spectroscopy. Spin frustration and asymmetric magnetic ordering due to dense spiral terraces are observed. Sizable modification of the layered antiferromagnetic order is found to be originating from the topological asymmetry as confirmed by the continuum micromagnetic simulation.
Journal Article↗
MPO-ANCA-associated pseudovasculitis in cardiac myxoma.
We describe a case of cardiac myxoma whose clinical presentation mimicked that of polyarteritis nodosa. The serum levels of MPO-ANCA and IL-6 were elevated on laboratory investigation and normalized after the removal of the tumor. We suggest that a 'true' vasculitic mechanism contributes to the pathogenesis of pseudovasculitis in cardiac myxoma.
Adult↗
Calcifying tendonitis of the gastrocnemius. A report of three cases.
We describe the clinical features of calcifying tendonitis in the medial head of gastrocnemius in three elderly female patients. The presenting symptom was chronic pain in the posteromedial area of the knee in two patients and acute pain in the back of the knee in one. All had limitation of movement of the knee and marked tenderness in the region of the tendinous origin of the medial head of gastrocnemius with posterior knee pain induced by stretching the tendon. An injection of 1% lidocaine and steroid into the tendon resulted in temporary relief from pain and improved movement.
Aged↗
Selective spatial attention induces short-term plasticity in human somatosensory cortex.
Early cognitive process in the primary somatosensory cortex (SI) was studied by measuring somatosensory evoked magnetic fields during selective attention tasks. We used vibratory stimuli to the index or middle finger with a frequency of 100 or 400 Hz for selective discrimination of spatial finger and non-spatial frequency attribute of stimuli. An early M50 component from the SI cortex indicated that the SI regions for the fingers were specifically segregated in a finger discrimination task but not in a frequency discrimination task or in a control condition. The task-dependent and immediate switchover of cortical finger representation demonstrates a dynamic SI activation for spatial information processing.
Adult↗
Visualization of the stop of microtubule depolymerization that occurs at the high-density region of microtubule-associated protein 2 (MAP2).
Individual microtubules (MTs) repeat alternating phases of polymerization and depolymerization, a process known as dynamic instability. Microtubule-associated proteins (MAPs) regulate the dynamic instability by increasing the rescue frequency. To explore the influence of MAP2 on in vitro MT dynamics, we correlated the distribution of MAP2 on individual MTs with the dynamic phase changes of the same MTs. MAP2 was modified selectively on its projection region by X-rhodamine iodoacetamide without altering the MT-binding activity. When the labeled MAP2 was added to MTs, the fluorescence was distributed along almost the entire length of individual MTs. However, the inhomogeneity of the distribution gradually became obvious due to the fluorescence bleaching, and the MTs appeared to consist of rapidly bleached portions (RBPs) and slowly bleached portions (SBPs), which were distributed randomly along the MT. By measuring the duration of fluorescence bleaching, the density of MAP2 in SBP was estimated to be approximately 2.5 times higher than the RBP. The average tubulin:MAP2 ratio in SBP was calculated to be 16. When the MT dynamics were observed by dark-field microscopy after determining the MAP2 distribution, rescues were always found to occur only at the SBPs. MTs also displayed intermittent shortening by repeated depolymerization phases separated by pause phases. In these cases, depolymerization phases stopped only at the SBPs. Not every SBP stopped depolymerization, but depolymerization always stopped at an SBP. Taken together, we suggest that there is a minimum density of MAP2 that is necessary to stop depolymerization.
Animals↗
Serial activation of distinct cytoarchitectonic areas of the human S1 cortex after posterior tibial nerve stimulation.
MEG recordings visualized non-invasively a dynamic anterior-posterior activation in the pyramidal cell population of the human primary somatosensory cortex (S1) after posterior tibial nerve stimulation. Somatosensory evoked fields (SEFs) were recorded over the foot area in response to right posterior tibial nerve stimulation at the ankle in six normal subjects. A newly developed MEG vector beamformer technique applied to the SEFs revealed two distinct sources in the mesial wall of the left hemisphere around the primary P37m response typically separated by 1.3 cm. The first source was located in area 3b and oriented toward the contralateral hemisphere. The second source was assumed to be in an area near the marginal sulcus and the source orientation was directed posteriorly. The first source began to be active during the initial slope of the P37m. The second source was active after the P37m peak and the signal intensities of the first and second sources were equal at a mean latency of 2.6 ms after the peak of P37m. Then the first source became inactive and the second source was dominant after about 5 ms post-P37m peak. These findings suggest that a single peaked posterior tibial nerve P37m consists of partially overlapping two subcomponents generated in area 3b and an area near the marginal sulcus.
Adult↗
Dynamic activation of distinct cytoarchitectonic areas of the human SI cortex after median nerve stimulation.
MEG recordings visualized non-invasively a serial mediolateral activation of the human somatosensory 3b area followed by a stationary activation of area 1 after median nerve stimulation. Somatosensory evoked fields (SEFs) were recorded over the hand area contralateral to the right median nerve stimulation at the wrist in six normal subjects. A newly developed MEG vector beamformer technique applied to the SEFs revealed two distinct sources (areas 3b and 1) in the primary somatosensory cortex (SI) during the primary N20m-P22m response in all subjects. The first source was located in area 3b, which started to move sequentially toward mediolateral direction 0.7 ms prior to the peak of N20m and ended its movement 1.4 ms after the peak with a total distance of 11.2 mm. We speculate that the movement reflects a sequential mediolateral activation of the pyramidal cells in area 3b, which is mediated by horizontal connections running parallel to the cortical surface. The second source in area 1, located 5.6 mm medial and 4.2 mm posterior to the first source, was active 1.0 ms after the N20m peak. Then, the first source became inactive and the second source was dominant. In sharp contrast with the first source, the second source was stationary. The different behavior of these two components (moving vs stationary) indicates independent parallel inputs to area 3b and area 1 from the thalamus.
Adult↗
Real-time memory on an excitable field.
Recently, we proposed a novel method for computing logic operations based on the time-sequential information in a geometrically arranged excitable field. As an extension of this study, in the present article we describe a strategy for creating real-time memory. Using a numerical simulation, we show that input pulse trains can be stored as a sequence of rotating traveling waves in a circular excitable field, by using its characteristics as a diode due to spatially asymmetric arrangement. Furthermore, through an experiment on an excitable chemical reaction, we demonstrate that this real-time memory actually works in the real world.
Journal Article↗
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↗
Specific somatosensory processing in somatosensory area 3b for human thumb: a neuromagnetic study.
OBJECTIVES: We examined the relation between somatosensory N20m primary responses and high-frequency oscillations (HFOs) after thumb and middle finger stimulation. METHODS: Somatosensory evoked fields (SEFs) from 12 subjects were measured following electric stimulation of the thumb and middle finger. SEFs were recorded with a wide bandpass (3-2000 Hz) and then N20m and HFOs were separated by subsequent 3-300 and 300-900 Hz bandpass filtering. RESULTS: The N20m peak-to-peak amplitude did not differ significantly between thumb and middle finger SEFs. In contrast, HFOs had a significantly larger number of peaks and were higher in the maximum amplitude and the total amplitude after thumb stimulation than after middle finger stimulation. CONCLUSIONS: Our present data demonstrate a different relation between N20m and HFOs after thumb and middle finger stimulation. In view of the fact that the human thumb has uniquely evolved functionally and morphologically, the somatosensory information from the thumb will be processed differently for a fine motor control. We speculate that HFOs are generated by inhibitory interneurons in layer 4 in area 3b. Thus, enhanced activity of interneurons reflected by high amplitude HFOs exerts stronger inhibition on downstream pyramidal cells in area 3b for thumb stimulation.
Adolescent↗
[Direct laryngoscopic extirpation and wound suture for hypopharyngeal lipoma: a case report].
We report a case of hypopharyngeal lipoma. An 82-year-old woman referred to our clinic for 10 years of wheezing and intermittent breathlessness developing 1 month before admission was found on laryngoscopic examination to have a mobile mass arising from the hypopharyngeal region intermittently obstructing the laryngeal airway. After emergency tracheotomy, the tumor was removed under direct laryngoscopy, given the patients age and general status. Under general anesthesia, the tumor was extirpated using a laser and electric scalpel under microlaryngoscopy. The operative wound was sutured under direct laryngoscopy using a specially designed probe with a U-shaped tip. The tumor was histologically diagnosed as lipoma. The surgical procedure enabled the operative wound to heal rapidly and oral feeding to start early.
Aged↗
[A new surgical technique combining autologous intracordal transplantation of fat and fascia for sulcus vocalis].
We developed a new surgical technique combining autologous intracordal transplantation of fat and fascia for sulcus vocalis. Fat tissue from the abdominal wall and fascia from the postauricular region were obtained and an incision was made on the lateral portion of the vocal cord and a small pocket prepared in the lamina propria using an elevator. After inserting fat tissue into the pocket, fascia was inserted to cover the fat graft to prevent its escape from the pocket. The surgical wound was then sutured using absorbable sutures. No evidence of postoperative absorption of transplanted fat tissue was seen, and vocal function improved postoperatively. This method proved useful as surgical treatment for sulcus vocalis.
Adipose Tissue↗