Structure-based design of an agonistic peptide targeting Fas

A small agonistic peptide FRAP-4 (WEWT, Fas reactive peptide-4) that binds to the human Fas molecule was discovered using our computer screening strategy named the Amino acid Complement Wave (ACW) method, which is based on the complementarities of interacting amino acids between comprehensive testing peptides and a target protein surface pocket. In silico docking studies demonstrated the specific interaction of FRAP-4 with the main Fas ligand (FasL) binding domain in the Fas molecule. An octamer of this peptide produced by carboxyl terminal linkages of polylysine branches (MAP), (FRAP-4)8-MAP, effectively induced apoptosis in human ovarian cancer cell line NOS4 cells that was associated with the activation of caspases-8, -9 and -3, and the cleavage of PARP. Alanine substitution of the N-terminal W in FRAP-4 resulted in complete loss of FasL-mimetic action of (FRAP-4)8-MAP, suggesting that the aromatic functionality at the N-terminal position W appears to play an essentially important role in Fas binding ability. These observations indicate that the FasL-mimetic peptide should serve as an excellent starting point for the design of effective compounds with FasL-mimetic activity. Furthermore, the ACW method for the structure-based design of optimized small peptides against receptor molecules such as Fas could open new avenues for the development of peptide mimetic and nonpeptidic organic forms to generate novel effective pharmaceuticals.

Sequential delivery of interferon-alpha gene and DCs to intracranial gliomas promotes an effective antitumor response

Effective presentation of tumor antigens by dendritic cells (DCs) is considered to be essential for the induction of antitumor T-cell responses. Apoptotic and necrotic tumors have been noted to be a robust antigen source for DCs. Because glioma cells undergo apoptosis after transfection with the type I interferon (IFN) gene and type I IFNs promote the stimulatory activity of DCs, we hypothesized that transfection of glioma cells with type I IFN genes and provision of DCs would promote particularly effective antitumor activity by both facilitating apoptosis of glioma cells and the presentation of the glioma antigens, thereby inducing specific immune responses against glioma cells. We have previously reported the proof of this hypothesis in vitro and in a subcutaneous tumor model. Here we report an extension of this approach in intracranial (i.c.) gliomas using adenoviral IFN-alpha (Ad-IFN-alpha) vector. Mice bearing day-5 i.c. GL261 glioma received sequential intratumoral (i.t.) delivery of Ad-IFN-alpha and bone marrow-derived syngeneic DCs. This treatment prolonged survival in that nine of 17 animals survived long term (> 60 days versus 0 of 10 control animals). Specific CTL activity was demonstrated following this regimen in the cervical lymph nodes, and the therapeutic efficacy was dependent upon CD8+ cells. Furthermore, these animals were protected against subsequent re-challenge with GL261 gliomas. DCs injected i.t. survived in the tumor and migrated into cervical lymph node. In vitro migration assays revealed the ability of DCs to migrate toward the tumor, suggesting that i.t. injected DCs migrate through the glioma. Taken together, this combination of gene therapy and cellular immunotherapy may be an effective future strategy for treating human gliomas.

Vascular supply of the subcutaneous pedicle of Nagata's method in microtia reconstruction

Nagata's method is a two-stage method for total ear reconstruction in patients with microtia. In the first stage of this procedure, mastoid flap and posterior lobule flap are elevated with a subcutaneous pedicle. However, contribution to the vascular supply by this pedicle has been controversial. We investigated the presence or absence of apparent vessels in the subcutaneous pedicle in 14 primary cases of microtia in the first stage operation. In all cases some vessels were included in the pedicle. In lobular and small concha type microtia, the vessels originated from the parotid fascia or aponeurotic tissue behind the remnant cartilage. In concha type microtia, apparent vessels could be preserved by including the perichondrium of the conchal cartilage. These findings suggest that the mastoid and posterior lobule flaps or W-shaped flap in Nagata's first stage operation are actually the perforator-based flaps. The source vessel of the perforators seemed to be the posterior auricular artery because of its location although further dissection was not performed in order not to damage the vascular supply. The presence of the vessels can augment the blood supply of not only W-shaped flaps but also the skin flap cephalad to them. By confirming the preservation of the perforators in the subcutaneous pedicle the surgeon may be able to trim the covering skin more safely.

Balance of risk of therapeutic hypothermia

The complications of therapeutic hypothermia sometimes undermine its clinical effects. In this study we investigated the efficacy and safety of therapeutic hypothermia based on analysis of 20 severe head injury cases from 6 institutions treated with therapeutic hypothermia in 1999. The twenty patients with severe head injury were enrolled prospectively based on the following indications; Glasgow Coma Scale of 7 or less on admission, age 60 or younger, and systric BP over 100 mmHg. A control group consisting of 21 patients with severe head injury met the same criteria but were treated without therapeutic hypothermia in other institutions. Clinical benefit were evaluated by a comparison of clinical result in the two groups defined according to the Glasgow Outcome Scale six months after injury. The hypothermia group was divided into two groups based on a target temperature [mild hypothermia group: 32-34 degrees C (n = 10); very mild hypothermia group: 35-36 degrees C (n = 10)]. The complication rate, clinical results and the duration of therapeutic hypothermia were analyzed between two groups. In the hypothermia group, 12 patients obtained a favorable outcome (Good Recovery or Moderate Disabled in GOS) and the mortality rate was 35%. In the control group, however only 5 patients had a favorable outcome and the mortality rate was 57%. Comparison between mild hypothermia and very mild hypothermia groups revealed no difference in clinical outcome. In the hypothermia group, severe pneumonia was seen in three patients, all in the mild hypothermia group with a hypothermic duration of over 120 hours. Mild hypothermia should be ended within 120 hours to avoid severe complication. When long-lasting therapeutic hypothermia of more than 120 hours is planned, very mild hypothermia is the treatment of choice.

Animal models of cervical artery dissection

We developed a canine model of arterial dissection and serially observed morphological changes angiographically and histopathologically to clarify the causes and mechanisms resulting in dissecting aneurysm formation or arterial occlusion. Intimal defects of various sizes and shapes were made on the arterial walls to provide an entry zone for dissection, so as to simulate the extent of arterial wall injury. Our experimental model showed angiographic and histopathological changes similar to those in clinical cases. As for our initial findings immediately after lesioning, either a double shadow (pseudolumen) or stenosis of the affected artery, due to compression from the subadventitial hematoma, was observed in the angiograms of all lesions. In some lesions with a pseudolumen, a dissecting aneurysm developed subsequently. Some arteries showing focal occlusion recanalized, and stenosis spontaneously improved. Very small dissections resulted in spontaneous healing, while a large intimal entry zone caused stenotic lesions. However, a medium-sized entry zone (4-6 mm) may induce aneurysm formation. The different features of dissection may be caused by the characteristics of flow into the subadventitial cavity and by thrombogenesis. Morphological changes after arterial dissection were closely related to the extent of intimal injury, suggesting that the size of the intimal entry zone may determine whether or not a dissecting aneurysm is formed.

Feasibility of photocrosslinkable chitosan as an embolization material for aneurysms. Biological reaction after aneurysm embolization

SUMMARY

The purpose of this study was to evaluate the feasibility of photocrosslinkable chitosan as an embolization material for aneurysms. Three experimental aneurysms were created in three Japanese white rabbits. All of the aneurysms were packed with chitosan hydrogel. Histopathologic data were analyzed on two, seven, and 30 days after embolization. Unorganized clots and minimal inflammation around the applied chitosan hydrogel were observed two days after implantation. After seven days, the chitosan was reduced and inflammatory response appeared. At 30 days, most of the aneurysm lumen was replaced with inflammatory cells, and the remaining chitosan was not observed. Severe complications such as anaphylaxis did not occur after the embolization with the chitosan. These results suggest that photocrosslinkable chitosan might be a candidate for an embolization material for endovascular treatment of cerebral aneurysms.

Radiological and pathological changes in the sinus of an experimental arteriovenous fistula of the rat

SUMMARY

The object of this study is to evaluate the radiological and pathological changes in the sinus of an experimental arteriovenous fistula of the rat. Twenty-five male Sprague-Dawley rats, including two control rats, were used for this study. A venous hypertension model in the transverse sinus was induced by means of anastomosis of a common carotid artery (CCA) to the ipsilateral external jugular vein (EJV). Rats were sacrificed 11 to 42 weeks after the procedure, then histopathological and immunohistopathological examinations were performed for the resected transverse sinus. Follow-up angiography was performed two to three weeks after the anastomosis in every case, and five months later in two rats. Patency of the anastomosed portion was confirmed in 12 of the 23 anastomosed rats. An ipsilateral carotid angiogram demonstrated a highflow arteriovenous (AV) shunt from the CCA to the sigmoid-to-transverse sinus and draining into the contralateral juglar vein. A contralateral angiogram displayed a steal phenomenon via the communicating artery. Histopathologically, the vein of the anastomosed portion and the transverse sinus were markedly dilated in with cases. There was a thickening the connecting tissue and a proliferation of fibroblast in four (50%) of the eight cases. Thrombus formation in the transverse sinus was found in one case. VEGF stained strongly in the endothelial hypertrophied area and in fibrous connective tissue around the transverse sinus compared to the control sinuses. Our results from this long-term observation of the radiological and pathological changes in the sinus exposed to hypertension resembled the clinical findings of a dural AV fistula.

Treatment strategy for aneurysms of the posterior cerebral artery

SUMMARY

The authors carried out a retrospective review of the records of 12 patients with aneurysms of the posterior cerebral artery (PCA). Four were asymptomatic, 1 presented with a mass effect, and 7 with a subarachnoid haemorrhage (SAH). Of the 7 ruptured aneurysms, 3 were embolized and 2 were clipped. However, 2 patients died from rebleeding before any treatment. Of the 5 unruptured aneurysms, 1 was embolized with coils but the remaining 4 have been conservatively observed. No aneurysms have ruptured during the follow-up period, and 3 have thrombosed spontaneously. According to our results, the PCA aneurysms should be treated aggressively in the early phase. Although the preservation of the anatomical integrity of the PCA should naturally be one of the prime objectives, PCA occlusion may sometimes be inevitable when treating large or fusiform aneurysms. On the other hand, conservative therapy is one of the options for the treatment of incidentally encountered unruptured ones, because these have the possibility of spontaneous thrombosis.

Local hyperthermia enhances thrombosis in aneurysms containing platinum coils

SUMMARY

Despite recent technical advances in embolization of cerebral aneurysms with platinum coils, some aneurysms eventually resulted in incomplete packing with remnant neck or dome filling. Such a situation with a remaining inflow zone may pose a risk of rupture and subsequent regrowth. Metals characteristically generate heat under high-frequency alternating magnetic fields (AMF). We used this property to induce local hyperthermia and promote thrombogenesis in incompletely packed aneurysms. Glass model aneurysms packed with coils were subjected to AMF to investigate the correlation between weight of platinum and temperature elevation and the correlation between flow rates of water through the model and temperature elevation. Next, activated coagulation time (ACT) of blood obtained from dogs was studied at various temperatures. Finally, side-wall aneurysms created in the canine carotid artery using a venous patch were packed with platinum coils. Change in temperature and angiographic changes were investigated after AMF application. In the glass model, the weight of platinum was correlated with elevation of temperature, and a negative logarithmic correlation was evident between flow rate and elevation of temperature. Elevation of blood sample temperature tended to shorten ACT. In canine carotid aneurysms, elevation of intra-aneurysmal temperature was confirmed and sufficient elevation of temperature was found to promote angiographically evident thrombogenesis of the remnant space after AMF application. Local hyperthermia may be useful in completing luminal obliteration of aneurysms after coil embolization. It may particularly useful for ruptured aneurysms to prevent the early rerupture.

Computer simulation of flow dynamics in an intracranial aneurysm. Effects of vessel wall pulsation on a case of ophthalmic aneurysm

SUMMARY

Using a supercomputer, the authors studied the effect of vessel wall pulsation on flow dynamics with a three-dimensional model simulating both a rigid and pulsatile style. The design of the aneurysm models was set with a 5 mm dome diameter and a 1 or 3 mm orifice size to simulate a carotid-ophthalmic aneurysm. Flow dynamics were analyzed according to flow pattern, wall pressure and wall shear stress. The flow pattern in the aneurysm sac showed the great difference between rigid and pulsatile models particularly in the small-neck aneurysm model. The arterial wall tended to be exposed to a higher pressure peak in the pulsatile model than in the rigid one, especially at its bifurcation and curved regions. Sites of shear stress peak were found on the aneurysmal dome as well as at the distal end of the orifice in both rigid and pulsatile models. The effects of vessel-wall pulsation should be considered whenever evaluating conditions in and around an aneurysm.

Nagoya university training system for neuroendovascular therapists

SUMMARY

It is very important to train more neuroendovascular therapists (NETists) in response to Japan's growing social needs. Since the supply of qualified NETists is still insufficient to cover Japanese institutions, therefore some emergency cases with indications for endovascular therapy may be overlooked, untreated or treated by other methods resulting in unfavorable outcomes. Thus, neuroendovascular therapies are situated as one of the important tratment modalities for neurosurgical diseases (1,2). We studied our present states of the endovascular neurosurgery and introduce our training system.

Effect of tactile interference stimulation of the ear in human primary somatosensory cortex: a magnetoencephalographic study

OBJECTIVE

To confirm the somatotopic representation of the ear in the primary somatosensory cortex (SI), we studied the tactile interference effects on somatosensory evoked magnetic fields (SEFs) following stimulation of the ear (Helix, Lobulus and Tragus).

METHODS

We applied tactile interference stimulation to the neck or face area continuously and concurrently while a time-locked electrical stimulation was applied to the ear. If the amplitude would be reduced by the interference, this would indicate that the cortical representation for both the time-locked electrical stimulation and the continuous interference stimulation overlapped. A two or 3-source model, Source 1 in the neck area of SI, Source 2 in the face area of SI, and Source 3 in the secondary somatosensory cortex (SII), was found to be the most appropriate by brain electric source analysis (BESA).

RESULTS

Amplitudes of Sources 1 and 2 in most interference conditions were decreased. Source 1 following stimulation of all 3 sites was significantly reduced when the interference was applied to the neck area. Source 2 following stimulation of all 3 sites was significantly reduced when the interference was applied to the face area.

CONCLUSIONS

These findings showed that the interference effect was found in both the neck and face areas of SI following the ear stimulation.

SIGNIFICANCE

The representation of the ear in SI might be located in both the neck and face areas.

Coil retrieval following embolization of cerebral aneurysms

SUMMARY

Failed coil embolization of cerebral aneurysms may be occasionally followed by direct surgical treatment. We had 5 patients who underwent coil retrieval and surgical clipping after coil embolization because of periprocedural complications. The patients, ranging in age from 40 to 71, had wide-neck aneurysms located at the anterior communicating artery (AcomA) in 3 patients, the middle cerebral artery (MCA) in 1, and the internal carotidophthalmic artery (IC-Ophthalmic) in 1. They were embolized with Guglielmi detachable coils (GDCs), which had to be retrieved within 8 days because of coil protrusion and migration in 3 patients, aneurysm rupture in 1, and increased mass effect due to coil compaction in 1. Coils were successfully removed with aneurysmotomy or arteriotomy under temporary trapping, aneurysms were then clipped or trapped. Three patients had a good outcome, but one suffered permanent visual disturbance and the other had a motor deficit. Our study revealed that a small AcomA aneurysm had a high risk of complication in a case of complex anatomy of the AcomA-A1-A2 complex with its difficult access. In addition, insufficient packing of the inflow zone in a large and symptomatic aneurysm may cause coil compaction and regrow with increasing mass effect. The indication and treatment strategy for these aneurysms should be carefully determined.

Treatment Strategy for Cerebral Aneurysms Based on the Evidence of the Efficacy of GDC Embolization

SUMMARY

The authors reviewed 531 patients with cerebral aneurysms treated with Guglielmi detachable coils (GDCs) over 5 years to clarify both the advantages and disadvantages of embolization based on the evidence of complications by aneurysm profile. There were 52 technical complications, 25 of which resulted in unfavorable patient outcomes. Intraoperative rupture, the most serious complication exacerbating the patient's condition, occurred in 19 patients, 4 of whom expired. All of these aneurysms were very small and were mostly located in the AcomA and PICA portions. Thirteen patients encountered thromboembolic complications, 6 of whom were elderly with acute ruptured aneurysms at MCA and the tip of BA. For large or giant aneurysms manifesting the mass effect, particularly those in the ICA-C2 portion compressing the optic nerve, the saccular packing did little to ameliorate the symptoms, and subsequent surgical or endovascular trapping was needed. Therefore, saccular embolization of endovascularly difficult, very small AcomA aneurysms and large C2 aneurysm with visual symptoms should be used sparingly based on a risk-benefit assessment.

Effect of early induction of hypothermia on severe head injury

Although therapeutic hypothermia for patients with head injury has improved the outcome, the results in the most severe cases (GCS 3-6) have not been satisfactory so far. We induced hypothermia in head injury patients within 3 hours after the trauma, and compared the outcome of the treatment without hypothermia. Fourteen patients with GCS less than 6 were entered into this study (age range 13 to 58, mean 27.0 years). Seven of them were treated by hypothermia and 6 by the conventional method. The patients undergoing hypothermia were cooled to 34 degrees C within 3 hours after injury, kept at 32-34 degrees C for 48 hours, and then rewarmed. The outcome was evaluated at 6 months post-trauma, and the results were compared in the two groups. Therapeutic hypothermia dramatically suppressed brain swelling on CT in 3 of 7 patients. Four patients including these 3 showed a favorable outcome (good or moderate disability) and 3 died in the hypothermia group. In the conventional treatment group, only 1 patient was moderately disabled and 6 exhibited an unfavorable outcome (severely disabled, vegetative, or death). Early induction of hypothermia can improve the outcome in patients with severe head injury by reducing the severe brain swelling.

Expression of Ki-67 antigen and vascular endothelial growth factor in sporadic and neurofibromatosis type 2-associated schwannomas

Neurofibromatosis type 2 (NF2) is a formidable disease with considerable morbidity. Among tumors associated with NF2, schwannomas are the most difficult to treat because they are multiple and tend to recur. Vascular endothelial growth factor (VEGF) has been reported to act as a survival factor for Schwann cells. We, therefore, investigated VEGF expression in NF2-associated and sporadic schwannomas. We also evaluated the proliferative potential of these tumors by Ki-67 staining (MIB-1 labeling index) and microvascular density by CD34 staining. Immunohistochemistry was performed in 8 schwannomas from 6 NF2 patients, 2 schwannomas from 2 probable NF2 patients and 10 sporadic schwannomas. VEGF immunostaining was present in most schwannomas: all sporadic schwannomas and 8 of 10 schwannomas from NF2 or probable NF2 patients (NF2 group). No difference was evident in VEGF staining between the 2 groups. MIB-1 labeling index was significantly higher in the NF2 group (3.8 +/- 1.7) than the sporadic group (2.0 +/- 1.0, p < 0.01). Microvascular density was higher in the NF2 group (12.9 +/- 6.0) than the sporadic group (9.4 +/- 3.5), but not significantly (p = 0.06). Although VEGF alone cannot explain the higher proliferative potential in NF2-associated schwannomas, VEGF could be a factor influencing the proliferative potential of schwannomas.

Functional magnetic resonance imaging evidence for a representation of the ear in human primary somatosensory cortex: comparison with magnetoencephalography study

Our previous study (T. Nihashi et al., 2001, Neuro- Image 13: 295-304), using magnetoencephalography (MEG), revealed somatotopy of the ear in the human primary somatosensory cortex (SI); that is, the signals following stimulation of the ear reach both the neck and face areas of the SI. However, since this was the first report on somatotopy of the ear in humans, we performed an fMRI activation study to confirm the somatotopic representation, and compared the electrical activity by MEG and the cerebral blood flow change by fMRI. We studied eight healthy subjects using 3-T MRI. We stimulated three parts of the left ear: the helix, the lobulus, and the tragus. First, we identified the location of the ear area in the SI based on our previous MEG study, in which equivalent current dipoles (ECDs) were located in the neck and/or face areas of the SI. Then, we determined the search volume as a sphere with a 15-mm radius, which was placed in the neck and/or face area. We analyzed whether or not fMRI activation occurred inside such spheres. Stimulation of the helix activated the neck area of the SI in four of eight subjects, and both the neck and face areas in two. No activation was observed in two subjects. Stimulation of the lobulus activated the neck area in one subject, the face area in two, both in four, and neither in one. Stimulation of the tragus activated the face in four, both in three, and neither in one. These fMRI findings confirm the result of MEG that the representation of the ear in the SI is separated into neck and face areas.

Cluster analysis on multiple drugs susceptibility supplements genotyping of methicillin-resistant Staphylococcus aureus

OBJECTIVE

To evaluate the typing power of cluster analysis of antimicrobial susceptibility.

METHODS

Results of pulsed-field gel electrophoresis in 71 strains of methicillin-resistant Staphylococcus aureus were compared with cluster analysis of the diameter of growth inhibition in 11 drugs. Subjects were a consecutive series of patients (n = 71) from the wards and outpatient units of a community teaching hospital.

RESULTS

The cluster analysis took 2 to 3 seconds once the data were entered into a computer. The sensitivity, specificity, and accuracy of the cluster analysis were 76.3%, 58.3%, and 73.2%, respectively, using genotyping as the reference.

CONCLUSIONS

The cluster analysis offered real-time epidemiologic data at minimal cost and labor, warranting its cost-effective role.

[Salvage operation for esophageal cancer after radical chemoradiotherapy]

We reviewed salvage surgery cases for esophageal cancer following radical chemoradiotherapy. From January 1998 through January 2001, 6 patients (4 men, 2 women) underwent salvage operation at our department. Mean age was 56 years (range: 46-66). According to the Japanese Society for Esophageal Diseases localization schema, there was one case in the upper third of the thoracic esophagus, 3 cases in the middle third and 2 cases in the lower third. The histology was squamous cell carcinoma in all cases. Our radical chemoradiotherapy regimen for esophageal cancer was fluorouracil (5-FU) 400 mg/m2/24 hours i.v. on days 1 to 5 and 8 to 12, cisplatin (CDDP) 40 mg/m2/2 hours i.v. on days 1 and 8, and concurrent radiation therapy (2 Gy/day on days 1 to 5, 8 to 12 and 15 to 19). This regimen was repeated in 5 weeks, followed by 5-FU 800 mg/m2/24 hours i.v. on days 1 to 5 and CDDP 80 mg/m2/2 hours i.v. on day 1, which was repeated in 4 weeks. After these chemoradiotherapy, patients who were confirmed to have local recurrence or esophagobronchial fistula underwent salvage operation. Postoperative complications were anastomosis leakage in 1 patient, and anastomosis stenosis in 2 and esophagobronchial fistula in 1. Although no postoperative hospitalized death occurred, 1 patient died because of empyema 3 months after salvage operation. Another patient died due to respiratory failure 15 months later. The salvage operation outcomes are not acceptable. Salvage procedure and indication for salvage intervention need to be changed.

Process of apoptosis induced by TNF-alpha in murine fibroblast Ltk-cells: continuous observation with video enhanced contrast microscopy

Apoptosis is originally defined by unique morphological changes of dying cells, and the biochemical hallmark associated with apoptosis is internucleosomal DNA fragmentation. However, few report has shown the precise time course of the apoptotic events. The present study was designed to try to clarify apoptotic processes using a video-enhanced contrast-differential interference contrast (VEC-DIC) microscopy. The morphological changes of murine fibroblast Ltk-cells treated with TNF-alpha were divided into four stages: (i) pre-apoptotic, (ii) cytoplasmic shrinkage, (iii) membrane blebbing, and (iv) ballooning. Almost of the cells underwent cytoplasmic shrinkage and membrane blebbing within 6 hours after TNF-alpha exposure, and at about 9 hours, they were in the ballooning stage. Based on these data, we investigated the relationship between morphological changes and other biochemical features. The earliest event was exposure of phosphatidyl-serine at the cytoplasmic membrane, which was already observed in the pre-apoptotic stage. Loss of mitochondrial membrane potential was observed in the cytoplasmic shrinkage stage. Caspase-8/-3 activities already started increasing in the pre-apoptotic stage, and reached their peak at 6 hours after TNF-alpha exposure. DNA fragmentation occurred in the late phase of the membrane blebbing.