Motoki Tanikawa

Surgical treatment of chronic subdural hematoma based on intrahematomal membrane structure on MRI.

Summary Background. To determine the optimal surgical management of chronic subdural hematoma (CSDH), we assessed which operative procedure, burr holes or small craniotomy, was more effective on 49 consecutive patients. Method. We retrospectively classified all cases into two groups according to the intrahematomal membrane structure of CSDH on T*2-weighted magnetic resonance (MR) imaging. The first group, labeled type B, included hematomas which had no intrahematomal membrane and/or were monolayer multilobule. The second group, labeled type C, consisted of hematomas which were divided into multiple layers by the intrahematomal membrane. Findings. The outcome of type C patients treated with burr holes was significantly inferior to that of those who underwent a small craniotomy in terms of the relative outcome of neurological grading, re-operation ratio, and postoperative hospital stay (p<0.05). Type C hematomas treated with burr holes also had inferior outcome compared with a small craniotomy in terms of the duration of hematoma until disappearance on postoperative CT (p<0.05). Interpretation. We concluded that a considerable number of cases appeared to need craniotomy and resection of intrahematomal membrane for complete recovery in CSDH, and that T*2-weighted MR imaging could be used as a basis for selecting the operative procedure for CSDH.

Facilitatory Roles of Novel Compounds Designed from Cyclopentenone Prostaglandins on Neurite Outgrowth-Promoting Activities of Nerve Growth Factor

Abstract: Cyclopentenone prostaglandins (PGs) are known to arrest the cell cycle at the G1 phase in vitro and to suppress tumor growth in vivo. However, their effects on neurons are unclear. Here, we report that some cyclopentenone PGs function as neurite outgrowth‐promoting factors. They promoted neurite outgrowth from PC12 cells and from dorsal root ganglion explants but only in the presence of nerve growth factor (NGF). We refer to these PGs as neurite outgrowth‐promoting PGs (NEPPs). Through study of the structure‐function relationship of NEPP1‐10 and related compounds, we found that the cross‐conjugated dienone moiety of NEPPs was essential for promoting neurite outgrowth, and NEPP10 was concluded to be the best candidate for drug development. We also investigated the intracellular mechanism of the promotion by NEPPs and obtained evidence that immunoglobulin heavy chain binding protein/glucose‐regulated protein 78 (BiP/GRP78) plays a role in the promotion, based on the following observations: Antisense nucleotides for BiP/GRP78 gene blocked the promotion of neurite outgrowth; BiP/GRP78 protein level increased in response to NEPPs; and overexpression of BiP/GRP78 protein by adenoviral gene transfer promoted the neurite outgrowth by NGF.

Potent Prostaglandin A1 Analogs That Suppress Tumor Cell Growth through Induction of p21 and Reduction of Cyclin E

Although the cyclopentenone prostaglandin A1 (PGA1) is known to arrest the cell cycle at the G1 phase in vitro and to suppress tumor growth in vivo, its relatively weak activity limits its usefulness in cancer chemotherapy. In an attempt to develop antitumor drugs of greater potency and conspicuous biological specificity, we synthesized novel analogs based on the structure of PGA1. Of the newly synthesized analogs, 15-epi-Δ7-PGA1 methyl ester (NAG-0092), 12-iso-Δ7-PGA1 methyl ester (NAG-0093), and ent-Δ7-PGA1methyl ester (NAG-0022) possess a cross-conjugated dienone structure around the five-member ring with unnatural configurations at C(12) and/or C(15) and were found to be far more potent than native PGA1 in inhibiting cell growth and causing G1arrest in A172 human glioma cells. These three analogs induced the expression of p21 at both RNA and protein levels in a time- and dose-dependent fashion. Kinase assays with A172 cells treated with these analogs revealed that both cyclin A- and E-dependent kinase activities were markedly reduced, although cyclin D1-dependent kinase activity was unaffected. Immunoprecipitation-Western blot analysis showed that the decrease in cyclin A-dependent kinase activity was due to an increased association of p21 with cyclin A-cyclin-dependent kinase 2 complexes, whereas the decrease in cyclin E-dependent activity was due to a combined mechanism involving reduction in cyclin E protein itself and increased association of p21. Thus, these newly synthesized PGA1analogs may prove to be powerful tools in cancer chemotherapy as well as in investigations of the structural basis of the antiproliferative activity of A series prostaglandins.

Cochlear Nerve Action Potential Monitoring with the Microdissector in Vestibular Schwannoma Surgery

We developed a cochlear nerve action potential (CNAP) monitoring technique using a microdissector and compared the results of CNAP and auditory brainstem response (ABR) monitoring. Thirty-six patients underwent vestibular schwannoma resection via the retrosigmoid approach to preserve hearing. Both CNAP with the microdissector and surface ABR were recorded during the operation. We used the microdissector as an intracranial electrode for CNAP monitoring. The CNAP waveform was classified into four types: triphasic, biphasic, positive, and flat. At the completion of the tumor resection, the triphasic waveform was observed in 11 patients and the biphasic waveform was observed in 11 patients. Hearing function was preserved in all of them, although it was preserved in only two patients with other CNAP waveform types. The prognostic value of CNAP is significantly higher than that of ABR. We found that although CNAP with a microdissector does not provide real-time monitoring, with the classification of waveforms it can be used as predictable tool for postoperative hearing more accurately than ABR.

Endoscopic Occipital Transtentorial Approach for Pineal Region Tumor

For pineal region tumors, the infratentorial supracerebellar approach and the occipital transtentorial approach (OTA) have currently been the most frequently used methods. Each of them has both advantages and disadvantages as reported elsewhere. In the following video, the author describes the use of an endoscopic OTA for pineal immature teratoma in a 10-year-old patient. Preoperative MRI revealed heterogeneous mass lesion with amaximum diameter of 35mmmainly in the third ventricle. After obtaining thorough informed consent, the operation was performed. All manipulations were achieved using 4 mm, 0◦ or 30◦ endoscope and ordinary instruments for endoscopic surgery through an occipital midline 4 cm incision and 2 cm keyhole craniotomy. As a contingency measure, we were prepared to switch to microscopic surgery by shaving hair beyond the primary skin incision to extend the craniotomy, and by having a microscope ready. The retraction of the occipital lobe, which is indispensable for OTA but risks causing homonymous hemianopsia, was felt to be reduced in this procedure, although we did not have any quantitative measurement for comparison. Orientation was natural and automatic because an excellently exposed operative view allowed precise imaging of surrounding structures on the same screen. There was essentially no blind spot in this procedure. Predicted difficulty in manipulation capability through a narrow corridor produced virtually no stress during surgery. After careful dissection, the tumor was successfully removed en bloc. The patient awoke from surgery without neurological deficits or complications, and gross total removal of the tumor was confirmed on postoperative MRI.

An Elderly Case with a Ruptured Cerebral Aneurysm Treated by GDC and CT Guided Stereotactic Hematoma Aspiration

An eighty-year-old man who had subarachnoid hemorrhage and large intracerebral hematoma caused by a ruptured aneurysm of the left middle cerebral artery was treated with acute dome embolization using Guglielmi detachable coil and subacute CT guided stereotactic aspiration of the hematoma. As a result of these less invasive treatments, he returned to his regular daily life without any neurological deficits or complications.

Urgent Optic Nerve Decompression via an Endoscopic Endonasal Transsphenoidal Approach for Craniopharyngioma in a 12-Month-Old Infant: A Case Report

Craniopharyngiomas are benign tumors and account for approximately 5.6–13% of all intracranial tumors in children. Diagnosis of pediatric craniopharyngioma is often delayed until the tumor becomes relatively large and manifests severe visual and/or endocrine disturbance. Endoscopic endonasal approaches have recently been introduced to surgery for craniopharyngioma. These techniques, however, have rarely been utilized in patients affected with craniopharyngioma as young as 1 year old. This report documents a 12-month-old male infant with sellar craniopharyngioma who presented with acute total vision loss. To increase the chances of visual recovery, an endoscopic endonasal optic nerve decompression was performed as an urgent procedure. After decompression, which resulted in improvement of his visual disturbance, gross total resection of the tumor was undertaken through an anterior interhemispheric approach at a later date. Tumor mass reduction through an endoscopic endonasal transsphenoidal approach followed by secondary radical total resection under craniotomy was considered to be useful in cases such as this when urgent optic nerve decompression is required.