Molecular and morphological analyses revealed a cryptic species of dojo loach Misgurnus anguillicaudatus (Cypriniformes: Cobitidae) in Japan

Although it has been reported that populations of the Japanese dojo loach Misgurnus anguillicaudatus (Cypriniformes: Cobitidae) belong to two distinct mitochondrial (mt)DNA (Type I and Type II), the taxonomic status of the species remains unresolved. To address this question, nuclear DNA and morphological analyses were performed on M. anguillicaudatus population in the Nakaikemi Wetland, where Type I and Type II lineages are sympatric. Results suggest the existence of a cryptic species (Type I) within the Japanese dojo loach.

Magnetoelectrical control of nonreciprocal microwave response in a multiferroic helimagnet

The control of physical properties by external fields is essential in many contemporary technologies. For example, conductance can be controlled by a gate electric field in a field effect transistor, which is a main component of integrated circuits. Optical phenomena induced by an electric field such as electroluminescence and electrochromism are useful for display and other technologies. Control of microwave propagation is also important for future wireless communication technology. Microwave properties in solids are dominated mostly by magnetic excitations, which cannot be easily controlled by an electric field. One solution to this problem is to use magnetically induced ferroelectrics (multiferroics). Here we show that microwave nonreciprocity, that is, different refractive indices for microwaves propagating in opposite directions, could be reversed by an external electric field in a multiferroic helimagnet Ba₂Mg₂Fe₁₂O₂₂. This approach offers an avenue for the electrical control of microwave properties.

Control of microwave propagation is important for future communication technology. Here, Iguchi et al. report the reversal of microwave nonreciprocity by an external electric field in a multiferroic helimagnet Ba₂Mg₂Fe₁₂O₂₂.

Japanese Direct Investment and its Impact on Migration in the ASEAN 4

Although the manufacturing sector's share of employment is still small in ASEAN-4 countries, the development of manufacturing, especially labor-intensive industries, will be indispensable for absorbing part of the increase in labor force. In these countries, Japanese direct investment (JDI) has been more highly concentrated in the manufacturing sector than JDI in other regions. The Japanese “New Asian Industrial Development (AID) Plan” is a comprehensive economic cooperation package, which supports the introduction of JDI and the promotion of exports in ASEAN-4 countries. JDI and AID may, in turn, help alleviate the domestic labor market situation and reduce the incentive for workers of ASEAN-4 countries to migrate to work overseas.

Effectiveness of third-line chemotherapy in recurrent ovarian cancer patients

OBJECTIVE

Despite recent advances in the treatment of recurrent ovarian cancer, little evidence exists describing the benefit of third- line chemotherapy. The present authors previously reported that the treatment-free interval (TFI) after second-line chemotherapy may predict a survival benefit of third-line chemotherapy, however the length of TFI was uncertain due to limited cases. In this study, the authors evaluated the length of TFI, which is correlated with the effectiveness of third-line chemotherapy and a prognostic factor of third-line chemotherapy.

MATERIALS AND METHODS

The authors reviewed the medical records of 85 women with recurrent ovarian cancer who received third-line chemotherapy after a paclitaxel/carboplatin (PC) regimen as first-line chemotherapy.

RESULTS

The response rate [complete response (CR) + partial response (PR)] and clinical benefit rate [(CBR): CR + PR + stable disease (SD)] during the TFI after second-line chemotherapy for 0-3 months, 3-6 months, and 6-12 months and ≥ 12 months were 9.8%, 0%, 0%, 43.8% and 15.7%, 50%, 66.7%, and 93.8%, respectively. The median overall survival (OS) from the onset of third-line chemotherapy was longer for TFI ≥ 3 months than for TFI 0-3 months (795 days vs. 281 days, p < 0.001). Finally, according to univariate (HR = 0.256; p < 0.001) and multivariate (HR = 0.264; p < 0.001) analyses, TFI was the independent significant prognostic factor for OS.

CONCLUSIONS

TFI less than three months after second-line chemotherapy may predict little survival benefit of third-line chemotherapy.

Admission hyperglycemia causes infarct volume expansion in patients with ICA or MCA occlusion: association of collateral grade on conventional angiography

BACKGROUND AND PURPOSE

Hyperglycemia (HG) is associated with infarct volume expansion in acute ischaemic stroke patients. However, collateral circulation can sustain the ischaemic penumbra and limit the growth of infarct volume. The aim of this study was to determine whether the association between HG and infarct volume expansion is dependent on collateral circulation.

METHODS

We performed a retrospective analysis of 93 acute ischaemic stroke patients with internal carotid artery or middle cerebral artery occlusion within 24 h of onset were retrospectively studied. HG was diagnosed in patients with an admitting blood glucose value ≥140 mg/dl. Angiographic collateral grade 0-1 was designated as poor collateral circulation and grade 2-4 as good collateral circulation. Infarct volume was measured at admission and at again within 7 days using diffusion-weighted magnetic resonance images.

RESULTS

Among 34 patients with poor collateral grade, the change in infarct volume was significantly greater in the HG group than in the non-HG group (106.0 ml vs. 22.7 ml, P = 0.002). Among the 59 patients with good collateral circulation, the change in infarct volume was greater in the HG group than in the non-HG group (53.3 ml vs. 10.9 ml, P = 0.047). Multiple regression analysis indicated that admission HG (P = 0.004), baseline National Institutes of Health Stroke Scale score (P = 0.018), and poor collateral circulation (P = 0.040) were independently associated with infarct volume expansion.

CONCLUSIONS

Infarct volume expansion was greater in individuals with HG on admission regardless of collateral circulation status.

Plasma brain natriuretic peptide predicts death during hospitalization in acute ischaemic stroke and transient ischaemic attack patients with atrial fibrillation

BACKGROUND AND PURPOSE

atrial fibrillation (AF) is the most powerful predictor of early death in patients with acute ischaemic stroke. We investigated whether the plasma brain natriuretic peptide (BNP) level on admission can serve as a biological marker of in-hospital death in acute ischaemic stroke and transient ischaemic attack (TIA) patients with AF.

METHODS

we prospectively enrolled ischaemic stroke and TIA patients with AF within 24 h of onset and measured plasma BNP on admission. Patients were divided into two groups: the deceased group, who died during hospitalization, and the survival group. The factors associated with in-hospital death were investigated by multivariate logistic regression analysis.

RESULTS

a total of 221 patients with AF were enrolled. Death occurred in 24 (10.9%) patients. The mean ± SD of the plasma BNP level of the deceased group was significantly higher than that of the survival group (714.1 ± 716.3 vs. 320.0 ± 380.7 pg/ml, P < 0.0001). The optimal cutoff level, sensitivity, and specificity of BNP levels to distinguish the deceased group from the survival group were 320 pg/ml, 79.2, and 69.0%, respectively. Multivariate logistic regression analysis demonstrated that age per 10 years increase (OR, 3.56; 95% CI, 1.728-7.346, P = 0.0006), internal carotid artery occlusion (OR, 10.20; 95% CI, 2.525-41.177, P = 0.0011), NIHSS score of >17 (OR, 4.68; 95% CI, 1.137-19.286, P = 0.0325), and plasma BNP level of > 320 pg/ml (OR, 4.74; 95% CI, 1.260-17.800, P = 0.0213) were independent factors associated with in-hospital death.

CONCLUSION

the plasma BNP level on admission can predict in-hospital death in acute ischaemic stroke and TIA patients with AF.

Microembolic signals at 48 hours after stroke onset contribute to new ischaemia within a week

BACKGROUND AND AIMS

We investigated whether new ischaemic lesions (NIL) on follow-up diffusion weighted magnetic resonance imaging (DWI) are associated with microembolic signals (MES) within 24 h or at 48 h after stroke onset.

METHODS

Patients had acute ischaemic stroke and were studied within 24 h of onset. Transcranial Doppler ultrasonography (TCD) was prospectively examined twice, within 24 h and at 48 h after onset. DWI was conducted twice, on admission and on day 7. NIL were defined as the presence of hyperintense lesions undetected on initial DWI.

RESULTS

125 patients were consecutively enrolled from November 2004 to March 2006. TCD detected MES in 49% within 24 h and in 29% at 48 h after onset. In 27 patients with small vessel disease, MES were found in 8 (30%) patients within 24 h and in 5 (19%) patients at 48 h after stroke onset. In contrast, in 20 patients with large vessel disease, 11 (55%) patients within 24 h and 7 (35%) at 48 h had MES. Follow-up DWI detected NIL in 28 of 125 patients (22%) and NIL were significantly more frequent in MES positive patients (42%) than in MES negative patients at 48 h (15%; p = 0.002). MES at 48 h (OR 3.9; 95% CI 1.5 to 10; p = 0.005), atrial fibrillation (OR 3.6; 95% CI 1.3 to 11; p = 0.013) and arterial lesions (OR 4.3; 95% CI 1.5 to 12; p = 0.007) represented independent factors for NIL.

CONCLUSION

The presence of MES at 48 h, atrial fibrillation and arterial lesions were associated with recurrence of cerebral ischaemia on DWI.

Right-to-left shunt and lacunar stroke in patients without hypertension and diabetes

We analyzed the frequency of cardiac embolic sources in 62 patients with acute lacunar stroke vs 50 controls. In post hoc analysis, 11 patients with lacunar stroke having neither hypertension nor diabetes mellitus (non-HDM group) had a higher frequency of right-to-left shunt (RLS) (82%) than patients with risk factors for lacunar stroke. RLS was also independently associated with the non-HDM group. Thus, RLS may contribute to lacunar stroke in patients without risk factors for lacunar stroke.

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.

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.

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.

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.

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.

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.

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.

[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.

An immunohistological study of the localization characteristics of thymus and activation-regulated chemokine in the allergic inferior turbinate mucosa with reference to the effectiveness of trichloroacetic acid treatment

To investigate the background of the effectiveness of trichloroacetic acid (TCA) treatment, we examined the localization of thymus and activation-regulated chemokine (TARC) on allergic inferior turbinate mucosa using immunohistological methods. After obtaining informed consent, only one side of the inferior turbinate was treated with 80% (wt/vol) TCA solution under topical anesthesia using 4% lidocaine with epinephrine in 19 cases of allergic rhinitis. Among those, 17 cases did not show clinical improvement and underwent nasal septal reconstruction surgery and turbinectomy. Bilateral inferior turbinate specimens were obtained. The untreated turbinate specimens showed positive TARC findings. The positive findings were confirmed in the outer side of cytoplasm in the stratified ciliated columnar epithelium but not in the goblet cell. In the lamina propria, the glandular tissue and afew of the infiltrated lymphocytes just beneath the epithelium up to the depth of 120 microm were found TARC-positive (TARC+). The average number of positive cells in one microscopic visual field using 100x magnification was 3.97 +/- 4.04. On the other hand, the epithelium of the TCA-treated side showed positive findings only in two cases. The TCA-treated side also showed a relative decrease in infiltrated cells. Even in areas where there still were infiltrated cells, they were confirmed to be TARC-negative (TARC-) after TCA treatment. It is considered that the regenerated epithelium after TCA treatment originates from the glandular epithelium with negative TARC expression existing in the area deeper than a 120-microm level and that this immunohistological change would lead to the effectiveness of TCA treatment.

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.

[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.

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.

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.

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.

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.

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.

Comparison of the depth of the desiccated zone with selected vaporizing-cutting electrodes: a basic study in animals

OBJECTIVE

To evaluate in an animal model the haemostatic efficacy of vaporizing-cutting (VC) electrodes recently developed for use in high-energy transurethral resection of the prostate (TURP).

MATERIALS AND METHODS

Four VC electrodes were assessed for their haemostatic efficacy in the muscle and liver of pigs (in vitro) and dogs (in vivo). The devices tested were the roller-cutting and Vapor Cut (Karl Storz GmbH, Germany); the Wedge (Boston Scientific Corp., Boston, USA); and the Uroloop (Endocare Inc., Irvine, CA). In each the depth of the desiccated zone was compared with that produced by a standard cutting loop electrode. Each electrode was attached to a scanning system (developed previously) that allowed the electrode pressure on the tissue surface (in 3% sorbitol solution) and the running speed to be adjusted. The same generator was used with all devices. The tissue (muscle or liver) was cut by running the electrode over the surface at 200, 250 or 300 W, with the loop electrode used as the reference. After completing the procedure, the surgical wound and the surrounding tissue were dissected out and the depth of the heat-affected zone (HAZ, defined as the desiccated zone) measured.

RESULTS

In pig muscle (stroke speed 5 mm/s) there was no significant difference in the depth of the HAZ between the four VC electrodes and the loop, or among the VC electrodes at any of the power levels tested. In pig liver (stroke speed 5 mm/s), the roller cutting and Vapor Cut electrodes produced a thicker HAZ than the loop at all power levels tested (P < 0.01). The Wedge electrode produced a significantly thicker HAZ than the loop at 200 and 300 W (P < 0.01). There were no significant differences in HAZ among the VC electrodes at any power level. In dog muscle in vivo (stroke speed 10 mm/s), the roller cutting, Vapor Cut and Wedge electrodes produced a significantly thicker HAZ at 250 W than the loop at 150 W (the usual power for TURP) (P < 0.01). There was no significant difference among the VC electrodes. In dog liver in vivo (stroke speed 10 mm/s), the roller cutting electrode produced a significantly thicker HAZ at 250 W than the loop at 150 W (P < 0.01).

CONCLUSIONS

The present VC electrodes produced a thicker desiccation zone at higher powers (200-300 W) than the standard loop at the usual power (150 W). The four VC electrodes produced a similar desiccation zone. With pig muscle and liver in vitro, regular loops used at a higher power created a desiccation zone that was 70-80% of the depth created by the VC electrodes.

Dynamic mediolateral activation of the pyramidal cell population in human somatosensory 3b area can be visualized by magnetic recordings

Dynamic mediolateral activation in the pyramidal cell population of the human somatosensory 3b area was studied non-invasively. Somatosensory evoked fields (SEFs) were recorded over the hand area contralateral to the right median nerve stimulation at the wrist. Localization of an equivalent current dipole (ECD) for N20m primary cortical response was successively calculated for periods of 2.4 ms around N20m peak where the signal-to-noise ratio exceeded 100 and the spatial resolution was approximately 0.3 mm. The ECD moved toward the anterior, lateral and inferior direction for a distance of 8.7 mm at a propagation velocity of 3.6 m/s. This direction was orthogonal to the orientation of apical dendrites of the pyramidal neurons in area 3b and parallel to the surface of the posterior bank of the central sulcus. These findings suggest that the sequential mediolateral activation of the pyramidal cells in the somatosensory cortex is mediated by horizontal connections running parallel to the cortical surface.

Sequential information processing during a mental arithmetic is reflected in the time course of event-related brain potentials

OBJECTIVE

We hypothesized that mental arithmetic is a complex of sequential information processing. In order to test the hypothesis, event-related potentials (ERPs) were measured during 3 mental tasks.

METHODS

Fifteen normal human subjects performed the following tasks; (1) subjects added up every digit delivered successively on a computer display, (2) subjects counted the number of presented digits, or (3) subjects counted the number of meaningless patterns. Spatiotemporal differences between ERP waveforms under the 3 tasks were studied within the period of 1200 ms post-stimulus.

RESULTS

During the adding task, N120-P180-N220 complex advanced in latency in the left frontal, central and parietal regions. P300 increased in amplitude in the frontal and temporal regions during adding and counting digits, which was specific to the digit presentation. A positive slow potential depended on the adding task and showed two spatiotemporal distributions; one was a widespread brain activity over the frontal, central, temporal and parietal regions observed within 400-820 ms, and another was a brain activity restricted to the frontal region lasting up to 1150 ms.

CONCLUSIONS

The results suggest that the early portion of ERPs reflects identification of physical attributes of stimuli and numeric meaning of digits, and that the positive slow potential reflects processes associated with calculation.

Distal-proximal somatotopy in the human hand somatosensory cortex: a reappraisal

The distal-proximal representation of the finger and palm in the first somatosensory cortex was reexamined. Somatosensory evoked magnetic fields (SEFs) were measured with a 37-channel first-order axial gradiometer system. Sensory stimulus comprising a 20-ms vibration at a frequency of 200 Hz was delivered to five successive sites in 3-cm increments along the distal-proximal direction over the volar surface of the right index finger and palm. Using a single dipole model, the sources and the signal strengths of the main peak (M50) of the SEFs were estimated. All of the sources were located in the 3b area. There were no statistically significant differences between the locations of dipoles evoked by stimulation of different sites. The results support those of our previous study using a 122-channel whole-head planar gradiometer system that orderly distal-proximal representation of the hand, as described in monkeys, is blurred in the adult human somatosensory cortex.

[A case of renal cell carcinoma associated with von Hippel-Lindau disease and the necessity for family genetic diagnosis]

We report a 47-year-old man who had bilateral renal cell carcinoma (RCC) associated with von Hippel-Lindau (VHL) disease. Surgical resection of hemangioblastomas and left nephrectomy for RCC had been done previously. This time, a small RCC was found in his right kidney and enucleation was performed to preserve renal function. His mother had retinal angioma, hemangioblastoma, and bilateral RCC. Hemangioblastoma was also found in his daughter. Genetic diagnosis was performed in his family and a germline VHL mutation was recognized. For improvement of the prognosis of VHL disease, genetic diagnosis and early clinical assessment are important.

Event-related potentials reflecting sequential information processing during a mental arithmetic task

The sequence of brain activities was identified with respect to the behavioral output indicated by the reaction time. The early portion of ERPs suggests two automatic processes irrespective of the adding task; one is identification of physical attributes of digits and patterns and the other is recognition of the numeric meaning specific to digits. The elicitation of the subsequent positive slow potential depends on the adding task, suggesting mental processes associated with calculation and memorizing the result of the sum. These stages of information processing concatenate sequentially during the time course of performing the adding task.