Neuroprotective effects of silymarin on ischemia-induced delayed neuronal cell death in rat hippocampus.

We examined the effects of silymarin, which was extracted from Silybum marianum, on delayed neuronal cell death in the rat hippocampus. Rats were divided into four groups: sham-operated rats (sham group), rats which underwent ischemic surgery (control group), rats which were treated with silymarin before and after ischemic surgery (pre group), and rats which were treated with silymarin after ischemic surgery only (post group). We performed the ischemic surgery by occluding the bilateral carotid arteries for 20min and sacrificed the rats one week after the surgery. Silymarin was administered orally at 200mg/kg body weight. Smaller numbers of delayed cell deaths were noted in the rat CA1 region of the pre- and post-groups, and no significant difference was observed between these groups. There were few apoptotic cell deaths in all groups. Compared to the control group, significantly fewer cell deaths by autophagy were found in the pre- and post-group. We concluded that silymarin exerts a preservation effect on delayed neuronal cell death in the rat hippocampus and this effect has nothing to do with the timing of administering of silymarin.

Multitarget, dual-electrode deep brain stimulation of the thalamus and subthalamic area for treatment of Holmes' tremor.

OBJECT: Holmes' tremor (HT) is generally considered to be a symptomatic tremor associated with lesions of the cerebellum, midbrain, or thalamus. Deep brain stimulation (DBS) therapy for essential tremor and parkinsonian tremor has proved quite successful. In contrast, surgical treatment outcomes for HT have often been disappointing. The use of 2 ipsilateral DBS electrodes implanted in parallel within the thalamus for severe essential tremor has been reported. Since dual-lead stimulation within a single target can cover a wider area than single-lead stimulation, it produces greater effects. On the other hand, DBS of the subthalamic area (SA) was recently reported to be effective for refractory tremor. METHODS: The authors implanted 2 DBS electrodes (one at the nucleus ventralis oralis/nucleus ventralis intermedius and the other at the SA) in 4 patients with HT. For more than 2 years after implantation, each patient's tremor was evaluated using a tremor rating scale under the following 4 conditions of stimulation: "on" for both thalamus and SA DBS; "off" for both thalamus and SA DBS; "on" for thalamus and "off" for SA DBS; and "on" for SA and "off" for thalamus DBS. RESULTS: The tremor in all patients was improved for more than 2 years (mean 25.8 ± 3.5 months). Stimulation with 2 electrodes exerted greater effect on the tremor than did 1-electrode stimulation. Interestingly, in all patients progressive effects were observed, and in one patient treated with DBS for 1 year, tremor did not appear even while stimulation was temporarily switched off, suggesting irreversible improvement effects. The presence of both resting and intentional/action tremor implies combined destruction of the pallidothalamic and cerebellothalamic pathways in HT. A larger stimulation area may thus be required for HT patients. Multitarget, dual-lead stimulation permits coverage of the wide area needed to suppress the tremor without adverse effects of stimulation. Some reorganization of the neural network may be involved in the development of HT because the tremor appears several months after the primary insult. The mechanism underlying the absence of tremor while stimulation was temporarily off remains unclear, but the DBS may have normalized the abnormal neural network. CONCLUSIONS: The authors successfully treated patients with severe HT by using dual-electrode DBS over a long period. Such DBS may offer an effective and safe treatment modality for intractable HT.

On-demand control system for deep brain stimulation for treatment of intention tremor.

OBJECTIVES: Intention tremor becomes evident only when patients intend to move their body and is characterized by dysmetria. We have developed an on-demand control system that triggers the switching on/off of deep brain stimulation (DBS) instantly for the control of intention tremor. MATERIAL AND METHODS: We used surface electrodes for the recording of electromyographic (EMG) activity, and the power of EMG activity was analyzed instantly employing the fast Fourier transform. The on-demand control system switched on DBS when only the power of tremor frequency exceeded the on-trigger threshold, and the system switched off DBS when the total power of EMG activity decreased below the off-trigger threshold. RESULTS: The on-demand control system triggered the switching on/off of DBS accurately, and controlled intention tremor completely. Our on-demand control system is small and portable, and suitable for clinical use. CONCLUSIONS: The on-demand control system for DBS is useful for controlling intention tremor and may decrease the incidence of tolerance to DBS and may be a powerful tool for various applications of neuromodulation therapy.

Changes in motor function induced by chronic motor cortex stimulation in post-stroke pain patients.

BACKGROUND: In well-designed multicenter studies, the protocol of continuing motor cortex stimulation (MCS) temporarily for 3-6 weeks was employed with rehabilitation therapy, and these studies showed some recovery of motor weakness in post-stroke patients. OBJECTIVES: We aimed to clarify the effects of long-term MCS and the optimal stimulation conditions to improve motor weakness in post-stroke patients. METHODS: We applied chronic MCS in 6 post-stroke pain patients with motor weakness. We then examined the correlation between the duration of daily MCS applied over 6 months and motor function assessed on the basis of the Fugl-Meyer Assessment (FMA) score of the patients. RESULTS: In the 6 patients with motor weakness, the FMA score of the upper extremity increased in 4 patients who underwent daily MCS for less than 4 h. On the other hand, 2 patients who continued excessive MCS to control their complicating post-stroke pain showed decreased FMA scores and worsened motor function owing to their increased rigidity and/or spasticity. These 2 patients recovered their motor function after their daily MCS was restricted to less than 4 h. CONCLUSIONS: These findings indicate that MCS could be a new therapeutic approach to improving motor performance after stroke by attenuating rigidity and/or spasticity. However, it may be important to define the appropriate number of hours and conditions of daily MCS.

Mast cell development and biostresses: different stromal responses in bone marrow and spleen after treatment of myeloablater, 5-fluorouracil, and inflammatory stressor, lipopolysaccharide.

Mast-cell-development in the bone-marrow (BM) and the spleen is restrictedly controlled by stromal-cells which produce positive-regulators such as stem cell factor (SCF), and negative-regulators such as transforming growth factor-ß (TGF-ß). How the balance between positive- and negative-regulation is achieved or maintained by stromal-cells is not well understood. We intravenously injected 5-fluorouracil (5-FU) and lipopolysaccharide (LPS) into C3H/HeN mice to disrupt mast-cell-development in order to reveal mechanisms of mast-cell-regulation. 5-FU treatment induces a rapid decrease in the number of mast-cell-progenitor (colony-forming unit (CFU)-mast) cells in the BM and spleen, followed by rapid recovery of CFU-mast numbers. Expression of the SCF gene is one-fiftieth the level of that of TGF-ß during the steady-state in BM and spleen. After 5-FU treatment, SCF mRNA levels in the BM markedly increased, approaching TGF-ß mRNA levels, whereas SCF levels in the spleen showed limited oscillations whose increases paralleled those in TGF-ß levels. In contrast, LPS treatment induces a rapid decrease in CFU-mast number in the BM and a rapid increase in of CFU-mast number in the spleen. After LPS treatment, SCF mRNA levels in the BM markedly decreased, whereas SCF levels in the spleen remained unchanged. These results suggest that regulation of mast-cell-development is dominated by negative-signals in the BM and spleen during the steady-state, and, under biostress-conditions such as 5-FU and LPS treatment, the balance between positive- and negative-regulation can be changed in the BM but not in the spleen. The difference in the regulation of mast-cell-development in the BM versus the spleen probably reflects the different roles of tissue-specific stromal-cells.

Chronological changes in astrocytes induced by chronic electrical sensorimotor cortex stimulation in rats.

Motor cortex stimulation (MCS) is a treatment option for various disorders such as medically refractory pain, poststroke hemiplegia, and movement disorders. However, the exact mechanisms underlying its effects remain unknown. In this study, the effects of long-term chronic MCS were investigated by observing changes in astrocytes. A quadripolar stimulation electrode was implanted on the dura over the sensorimotor cortex of adult rats, and the cortex was continuously stimulated for 3 hours, 1 week, 4 weeks, and 8 weeks. Immunohistochemical staining of microglia (ionized calcium-binding adaptor molecule 1 [Iba1] staining) and astrocytes (glial fibrillary acidic protein [GFAP] staining), and neuronal degeneration histochemistry (Fluoro-Jade B staining) were carried out to investigate the morphological changes following long-term chronic MCS. Iba1 staining and Fluoro-Jade B staining showed no evidence of Iba1-positive microglial changes or neurodegeneration. Following continuous MCS, GFAP-positive astrocytes were enlarged and their number increased in the cortex and the thalamus of the stimulated hemisphere. These findings indicate that chronic electrical stimulation can continuously activate astrocytes and result in morphological and quantitative changes. These changes may be involved in the mechanisms underlying the neuroplasticity effect induced by MCS.

Thalamic deep brain stimulation for the treatment of action myoclonus caused by perinatal anoxia.

BACKGROUND: Perinatal anoxia rarely causes myoclonus as the main neurologic abnormality. The exact neuronal mechanism underlying myoclonus induced by perinatal anoxia remains unknown. Some studies have indicated that the development of involuntary movements may be related to the maturation of the thalamus after birth. OBJECTIVES AND METHODS: Here, we describe the first case of a patient who developed action myoclonus after experiencing perinatal anoxia and was successfully treated by chronic deep brain stimulation (DBS) of the thalamus (thalamic DBS). RESULTS AND CONCLUSION: The effectiveness of chronic thalamic DBS in this patient supports the concept of involvement of the thalamus in post-perinatal anoxic myoclonus.

Thalamic deep brain stimulation for writer's cramp.

OBJECT: Writer's cramp is a type of idiopathic focal hand dystonia characterized by muscle cramps that accompany execution of the writing task specifically. In this report, the authors describe the clinical outcome after thalamic deep brain stimulation (DBS) therapy in patients with writer's cramp and present an illustrative case with which they compare the effects of pallidal and thalamic stimulation. In addition to these results for the clinical effectiveness, they also examine the best point and pattern for therapeutic stimulation of the motor thalamus, including the nucleus ventrooralis (VO) and the ventralis intermedius nucleus (VIM), for writer's cramp. METHODS: The authors applied thalamic DBS in five patients with writer's cramp. The inclusion criteria for the DBS trial in this disorder were a diagnosis of idiopathic writer's cramp and the absence of a positive response to medication. The exclusion criteria included significant cognitive dysfunction, active psychiatric symptoms, and evidence of other central nervous system diseases or other medical disorders. In one of the cases, DBS leads were implanted into both the globus pallidus internus and the VO/VIM, and test stimulation was performed for 1 week. The authors thus had an opportunity to compare the effects of pallidal and thalamic stimulation in this patient. RESULTS: Immediately after the initiation of thalamic stimulation, the neurological deficits associated with writer's cramp were improved in all five cases. Postoperatively all preoperative scale scores indicating the seriousness of the writer's cramp were significantly lower (p < 0.001). In the patient in whom two DBS leads were implanted, the clinical effect of thalamic stimulation was better than that of pallidal stimulation. During the thalamic stimulation, the maximum effect was obtained when stimulation was applied to both the VO and the VIM widely, compared with being applied only within the VO. CONCLUSIONS: The authors successfully treated patients with writer's cramp by thalamic DBS. Insofar as they are aware, this is the first series in which writer's cramp has been treated with DBS. Thalamic stimulation appears to be a safe and valuable therapeutic option for writer's cramp.

Thalamic sensory relay nucleus stimulation for the treatment of peripheral deafferentation pain.

We applied chronic deep brain stimulation (DBS) of the thalamic nucleus ventralis caudalis (Vc) for the treatment of peripheral deafferentation pain. The subjects included 11 cases of phantom limb pain and 7 of root or nerve injury pain without phantom sensation. In the phantom limb pain patients, the spike density markedly increased in the same area of the Vc where microstimulation induced paresthesia in the part with phantom sensation. Reorganization of the receptive field representation within the Vc was also demonstrated by microrecording and microstimulation. In the root or nerve injury pain patients with severe allodynia and without phantom sensation, oscillating neural hyperactivity appeared when the allodynia was induced during single-cell recording in the Vc. In both groups stimulation of these areas with the DBS electrode was useful for achieving pain reduction. Inhibition of spinothalamic tract neurons, restoration of the original receptive field representation and modulation of thalamocortical rhythmic oscillations are proposed to play important roles in a possible mechanism of Vc-DBS for the treatment of deafferentation pain.

Hyperbaric oxygen stimulates cell proliferation and normalizes multidrug resistance protein-2 protein localization in primary rat hepatocytes.

Hyperbaric oxygen therapy (HBO) has been used for many clinical treatments, including primary liver non-function. However, the cellular mechanism by which HBO treatment ameliorates liver function is not understood. Therefore, the purpose of this study was to elucidate this cellular mechanism using primary cultured rat hepatocytes in in vitro studies. Hepatocytes were treated with HBO at 1 day after plating, and the morphological and functional characteristics of bile canaliculi formed in cultured hepatocytes were observed by time-lapse microscopy. Multidrug resistance protein-2 localization was observed by confocal laser microscopy. In cultured hepatocytes, the labeling index in the HBO group at 2 days after treatment was significantly higher than that in the control group. In addition, the proliferating cellular nuclear antigen level in the HBO group was significantly higher than that in the control group. The contraction of the bile canaliculi in the HBO group was slower than in the control group and the dilatation of bile canaliculi in the HBO group was much larger than in the control group. Multidrug resistance protein-2 in the HBO group was localized at the apical membrane. These results show that HBO stimulates hepatocytes to proliferate and HBO normalizes multidrug resistance protein-2 localization to the apical membrane, which could dilate bile canaliculi.

Difference in surgical strategies between thalamotomy and thalamic deep brain stimulation for tremor control.

Stereotactic targeting strategies differ between thalamotomy and thalamic deep brain stimulation (DBS) for tremor control. In thalamotomy, a minimal radiofrequency lesion created within the lateral portion of the nucleus ventralis intermedius (Vim) often affords the best control of parkinsonian tremor, supporting the assumption that there is a concentrated cluster of cells within this area which is responsible for tremor. However, this assumption may not always be true; such neural elements sometimes appear to spread out across wide areas. Cells with tremor-frequency activity are widely distributed over the areas extending from the Vim to the nuclei ventralis oralis posterior and anterior (Vop and Voa). All of these cells appear to be more or less involved in tremor generation, especially in patients with essential tremor and post-stroke tremor. In contrast to radiofrequency lesions for thalamotomy, electrodes for DBS can be arranged in such a way that wide areas can be stimulated, if necessary. For this purpose, it is critically important to determine optimal placement and orientation of DBS leads for arranging the electrodes to yield maximal benefits in patients with tremor.

Deep brain stimulation for the treatment of parkinsonian, essential, and poststroke tremor: a suitable stimulation method and changes in effective stimulation intensity.

OBJECT: The tremor-suppression effect resulting from long-term stimulation of the thalamic nucleus ventralis intermedius (Vim) and the nucleus ventralis oralis posterior (Vop) was examined in the treatment of parkinsonian, essential, and poststroke tremor. METHODS: After identifying the accurate anterior border of the nucleus ventrocaudalis (Vc), deep brain stimulation (DBS) electrodes with four contacts were inserted into the Vim-Vop region at an angle of between 40 and 50 degrees from the horizontal plane of the anterior commissure-posterior commissure line. Two distal contacts were placed on the Vim side and two proximal contacts on the Vop side. The best sites of stimulation and parameters of bipolar stimulation were selected in each case and follow-up examinations were conducted for at least 2 years. In all 15 cases of parkinsonian tremor (18 sides) and in 14 of 15 cases of essential tremor (24 of 25 sides), cathodal stimulation of the Vim side with anodal stimulation of the Vop side was determined to be the best choice to suppress the tremor. In poststroke tremor, however, six of 12 cases (six of 12 sides) were selected for cathodal stimulation of the Vop side with anodal stimulation of the Vim side. The average stimulation intensity 1 month after initiation of DBS was 1.61 V in cases of parkinsonian tremor, 1.99 V in cases of essential tremor, and 2.39 V in cases of poststroke tremor. A comparison of stimulation intensities required at 1 and 24 months after initiation of DBS revealed that the lowest effective stimulation intensity increased 24.2% in cases of parkinsonian tremor, 21% in cases of poststroke tremor, and 46.9% in cases of essential tremor. Suppression of tremor was achieved in all cases (42 cases, 55 sides) during a period of 2 years. Nevertheless, two cases of poststroke tremor required dual-lead stimulation at the unilateral Vim-Vop region from the start of DBS, and two cases of essential tremor and one case of poststroke tremor required a stimulation intensity that was high enough to evoke unpleasant paresthesia and slight motor contraction during the follow-up period. CONCLUSIONS: Effective stimulation sites and stimulation intensities differ in different kinds of tremor; Vim and Vop stimulation is necessary in many cases. Interactions of the Vim and Vop under the control of interconnected areas of the motor circuitry may play an important role in both the development and DBS-induced suppression of tremor.

Dual-floor burr hole adjusted to burr-hole ring and cap for implantation of stimulation electrodes. Technical note.

Using a new perforator, the authors have developed a new dual-floor burr-hole method for use in deep brain stimulation therapy. The modification is called "dual-floor" because the usual 15-mm-diameter burr hole, which is located centrally and reaches the dura mater, is surrounded by a 4-mm-wide rim that is also planed downward by the new perforator to a depth of 4 mm. This dual-floor burr hole is adjusted to fit the burr-hole ring and cap that are are supplied by the electrode manufacturer. Such a method eliminates bulging of the scalp just over the burr-hole ring and cap. In addition, it is helpful for securing a tight fixation between the burr-hole ring and the skull.

Motor cortex stimulation in patients with post-stroke pain: conscious somatosensory response and pain control.

We analyzed the conscious sensory responses to cortical stimulation of 31 patients with post-stroke pain who underwent motor cortex stimulation (MCS) therapy. During surgery for electrode placement, a sensory response (tingle projected to a localized peripheral area) was elicited by high-frequency stimulation (50 Hz) in 23 (84%) from the somatosensory cortex, and in 16 (52%) from the motor cortex without muscle contraction. Unpleasant painful sensation was induced or their original pain was exacerbated in 12 patients (39%) when the somatosensory cortex was stimulated and in two (6%) when the motor cortex was stimulated. Somatosensory responses were induced in eight (25%) even by low-frequency stimulation (1-2 Hz) of the motor cortex at an intensity below the threshold for muscle contraction. In contrast, among 20 nonpain patients who underwent a similar procedure for cortical mapping in epilepsy or brain tumor surgery, a sensory response was produced by high-frequency stimulation in only eight (40%; p < 0.02) from the somatosensory cortex and four (20%; p < 0.03) from the motor cortex. Pain sensation was not induced by stimulation of the somatosensory cortex (p < 0.002) or motor cortex in any of these patients. In addition, none of these patients reported a sensory response to low-frequency stimulation. In both of the two post-stroke pain patients who reported abnormal pain sensation in response to stimulation of the motor cortex, MCS failed to control their post-stroke pain. These findings imply that the sensitivity of the perceptual system even to activity of the motor cortex is heightened in post-stroke pain patients, which can sometimes hinder pain control by MCS.