Protein-Ligand Interaction Analyses with Nuclear Magnetic Resonance Spectroscopy Enhanced by Dissolution Triplet Dynamic Nuclear Polarization

Solution-state nuclear magnetic resonance spectroscopy (NMR) is a powerful method for the analysis of intermolecular interactions within a biomolecular system. However, low sensitivity is one of the major obstacles of NMR. We improved the sensitivity of solution-state ¹³C NMR for the observation of intermolecular interactions between protein and ligand using hyperpolarized solution samples at room temperature. Eutectic crystals composed of ¹³C-salicylic acid and benzoic acid doped with pentacene were hyperpolarized by dynamic nuclear polarization using photoexcited triplet electrons, and a ¹³C nuclear polarization of 0.72 ± 0.07% was achieved after dissolution. The binding of human serum albumin and ¹³C-salicylate was observed with several hundred times sensitivity enhancement under mild conditions. The established ¹³C NMR was applied for pharmaceutical NMR experiments by observation of the partial return of the ¹³C chemical shift of salicylate by competitive binding with other non-isotope-labeled drugs.

Prediction of 1H Singlet Relaxation via Intermolecular Dipolar Couplings Using the Molecular Dynamics Method

Dissolution dynamic nuclear polarization has been applied in various fields, including chemistry, biology, and medical science. To expand the scope of these applications, the nuclear singlet state, which is decoherence-free against dipolar relaxation between spin pairs, has been studied experimentally, theoretically, and numerically. The singlet state composed of proton spins is used in several applications, such as enhanced polarization preservation, molecular tagging to probe slow dynamic processes, and detection of ligand-protein complexes. In this study, we predict the lifetimes of the nuclear spin states composed of proton spin pairs using the molecular dynamics method and quantum chemistry simulations. We consider intramolecular dipolar, intermolecular dipolar between solvent and solute, chemical shift anisotropy, and spin-rotation interactions. In particular, the relaxation rate of intermolecular dipolar interactions is calculated using the molecular dynamics method for various solvents. The calculated values and the experimental values are of the same order of magnitude. Our program would provide insight into the molecular design of several NMR applications and would be helpful in predicting the nuclear spin relaxation time of synthetic molecules in advance.

3D CT Angiography as a Pre-Embolization Study for Embolization of Cerebral Aneurysms

An image guide for aneurysm embolization based on three dimensional CT angiography is reported. Multiplanner reformation (MPR) can measure the neck and dome of the aneurysm accurately enough to select the first coils for aneurysms.

For neck evaluation, cut model and virtual endoscope are helpful because we can observe the neck from inside of dome or parent artery. Proximal arteries are visualized by 3D images and MPR if needed.

Using laser lithography, we can get a real model of aneurysm and parent artery through which we can insert microcatheters and coils. 3D CTA is a dependable modality for embolization of cerebral aneurysms.

In vitro measurement of tissue integrity during saccular aneurysm embolizations for simulator-based training

In the domain of endovascular neurosurgery, the measurement of tissue integrity is needed for simulator-based training and for the development of new intravascular instruments and treatment techniques. In vitro evaluation of tissue manipulation can be achieved using photoelastic stress analysis and vasculature modeling with photoelastic materials. In this research we constructed two types of vasculature models of saccular aneurysms for differentiation of embolization techniques according to the respect for tissue integrity measurements based on the stress within the blood vessel model wall. In an aneurysm model with 5 mm dome diameter, embolization using MicroPlex 10 (Complex 1D, with 4 mm diameter loops), a maximum area of 3.97 mm² with stress above 1 kPa was measured. This area increased to 5.50 mm² when the dome was touched deliberately with the release mechanism of the coil, and to 4.87 mm² for an embolization using Micrusphere, (Spherical 18 Platinum Coil). In a similar way trans-cell stent-assisted coil embolization was also compared to human blood pressure simulation using a model of a wide-necked saccular aneurysm with 7 mm diameter. The area with stress above 1kPa was below 1 mm² for the pressure simulation and maximized at 3.79 mm² during the trans-cell insertion of the micro-catheter and at 8.92 mm² during the embolization. The presented results show that this measurement system is useful for identifying techniques compromising tissue integrity, comparing and studying coils and embolization techniques for a specific vasculature morphology and comparing their natural stress variations such as that produced by blood pressure.

Subcutaneous hematoma associated with manual cervical massage during carotid artery stenting. A case report

We describe a patient with subcutaneous hematoma associated with manual cervical massage during carotid artery stenting.A 73-year-old man with left cervical carotid artery stenosis presented with left amaurosis fugax. We performed carotid artery stenting using distal embolic protection with balloon occlusion. Dual antiplatelet therapy was maintained in the periprocedural period and an anticoagulant agent was administered during the procedure. Because the aspiration catheter became entrapped by the stent, it did not reach the distal side of the stenotic lesion, and manual compression of the cervical region was therefore performed. Immediately afterwards, a subcutaneous hemorrhage occurred in the cervical region. There was no postoperative dyspnea due to enlargement of the hematoma, which was absorbed spontaneously.Cervical subcutaneous hematoma can occur in the cervical region due to cervical massage in patients who are receiving adjuvant antiplatelet therapy and anticoagulation therapy.

Uneven distribution of the luxS gene within the genus Campylobacter

Polymerase chain reaction (PCR) amplification was performed on 20 isolates of five Campylobacter species using a degenerate primer pair designed in silico to generate a product of the luxS gene or its homologue from Campylobacter organisms. Although the primer pair successfully amplified products of approximately 500 base pairs (bp) with the eight isolates of C. jejuni and C. coli and some of C. upsaliensis and C. fetus, it failed to amplify fragments with all four isolates of C. lari (two urease-negative C. lari; two urease-positive thermophilic campylobacters). When Southern blot hybridisation analysis was carried using the mixed luxS gene fragments prepared from the C. jejuni, C. coli, C. upsaliensis and C. fetus strains as a probe, all C. jejuni, C. coli, C. upsaliensis and C. fetus isolates gave positive signals, but no positive signal was detected with any C. lari isolate. These results clearly indicate that C. jejuni, C. coli, C. upsaliensis and C. fetus carry the luxS gene or its homologue. However, no luxS gene or its homologue was identified to occur in the C. lari genome. Although autoinducer-2 assays were positive in C. jejuni, C. coli, C. upsaliensis and C. fetus isolates, it was negative with all the C. lari isolates examined. In addition, a biofilm formation assay demonstrated that biofilm formation in the C. lari species does not appear to correlate with the occurrence of the luxS gene because biofilm formation occurred among some isolates of C. lari.

Total compensation of pulse transients inside a resonator

The profile of rf pulses that nuclear spins experience inside a resonator deviates from that of rf voltage signals generated by a NMR spectrometer according to users' pulse programming, when change of the profile in time is comparable to or shorter than the time constant of the resonator. In our previous work [Takeda et al., J. Magn. Reson. 197 (2009) 242-244], we proposed active compensation of rf pulse transients, in which the amplitude transient of the rf pulse can be suppressed without sacrificing the Q factor of the probe. Here we extend the idea of active compensation toward total compensation of the amplitude as well as phase transients. By measuring the transient response of the probe to a given excitation using a pickup coil, the response function determining the transient behavior of the probe is numerically obtained. Then, by numerically solving the convolution equation with the help of Laplace transformation, one can obtain the amplitude and phase profiles of the pulse that should be programmed in the spectrometer in order to apply the rf pulses to the nuclear spins as intended. Accurate rf pulsing based on this idea is experimentally demonstrated, and prospect and requirements for coping with the receiver dead-time problem are discussed.

Fine Structure of Detached Coils Observed by Micro-CT

SUMMARY

Detached GDC was observed by high resolutional industrial microCT, whose resolution was higher than 0.1 mm. Unexpected destruction of the coils (kinking) was detected and unraveling also clearly visualized. Much higher resolution can improve safe and effectivity of GDC procedure.

Autonomous catheter insertion system using magnetic motion capture sensor for endovascular surgery

BACKGROUND

In order to reduce fluoroscope usage in endovascular surgery, there is a need to develop autonomous catheter insertion systems.

METHODS

We propose a system for tracking the position and speed of a catheter using a magnetic motion capture sensor to provide feedback to a catheter-driving mechanism, to perform autonomous catheter insertion in major vasculature. Catheter insertion speed control and path reconstruction experiments were performed with the system inside a silicone model of major vasculature to simulate surgery.

RESULTS

The system controlled the catheter for speeds of 6.14 mm/s and reproduced a two-dimensional path inside the silicone blood vessel phantom with less than 7 mm of error.

CONCLUSIONS

We found that error in speed control rises as a result of friction between the catheter and the model wall. Path reconstruction error depends on the model's cross-sectional diameter, the properties of the catheter insertion mechanism, the magnetic sensor and the system guidance technique.

Extracranial vertebral artery aneurysm associated with neurofibromatosis type 1. A case report

SUMMARY

Extracranial vertebral artery aneurysm associated with neurofibromatosis (NF1) is very rare. The aneurysm was successfully treated by endovascular trapping of the aneurysm and proximal vertebral artery with coils.

Assessing Prognosis of Areas of Acute Cerebral Ischemia Using Perfusion CT

SUMMARY

Vascular recanalization by the vascular reconstruction method can dramatically improve ischemic symptoms in patients with acute cerebral ischemia. However, this treatment method is frequently associated with haemorrhagic complications. The indications for this therapeutic approach have been described in a number of studies in the literature. The present paper discusses the possibility of assessing the prognosis of ischemic areas using perfusion CT (PCT) by comparing the results obtained before and after thrombolytic therapy. Twenty-six patients underwent vascular reconstruction at our hospital between July 2002 and March 2004. Of these patients, six who underwent PCT before treatment and showed adequate recanalization following vascular reconstruction were included in the present study. PCT images were obtained using the first-pass bolus-tracking method with a 16-row multislice helical CT scanner. Areas of cerebral ischemia were evaluated by CT before and after vascular reconstruction. A region of interest was placed in the area showing low density in CT images before vascular reconstruction. The mean average CBF (mL/min/100 g), CBV (mL/100 g), and MTT (s) values were calculated in areas with and without cerebral infarction after vascular reconstruction. The %CBF, % CBV, and %MTT values relative to the normal side were evaluated with reference to the time until recanalization. Transarterial vascular reconstruction resulted in full recanalization in four patients and partial recanalization in two. The mean time from onset to recanalization was 284.7 +/- 63.27 minutes and was not longer than six hours in any patient. The patient prognosis results in terms of GOS were GR in two patients, MD in three patients, and SD in one patient. Based on comparison of the time after examination to recanalization, the %CBF showed a significant positive correlation in the salvaged area (Y = 47.321 + 2.491 x %CBF:R(2) = 0.792, p < 0.05). A significant correlation was not observed in %CBV, but %MTT showed a significant negative correlation (Y = 269.45 - 0.356 x %MTT:R(2) = 0.794, p < 0.05). The %CBF and %MTT results obtained by PCT performed before transarterial vascular reconstruction suggest that it may be possible to estimate the time before vascular reconstruction and the relationship with prognosis. These findings are expected to help ensure the appropriate application of vascular reconstruction and to provide useful information for developing optimal therapeutic protocols, thus reducing complications. In addition, because the results are based on the time after examination, the appropriate therapeutic approach can be determined even when the time of onset of ischemia is uncertain.

Computational Fluid Dynamics for Brain Circulation and Aneurysm with Therapeutic Devices

We analysed fluid dynamics at brain arteries having multiple inflow and out flow like Willis ring based on clinical imaging modalities. In addition, we analysed fluid dynamics with therapeutic devices like coils and stents to simulate their influences to blood flow.

3D CTA and MRA obtained three-dimensional structures of the brain vessels. The centreline was obtained from the three dimensional structure. Diameter of the blood vessels was measured by 3D CTA/MRA then smooth surfaced blood vessel models were created. For the fluid analysis, we developed a home brew software which can display parameters such as streamline, etc.

In addition, our CFD (computational fluid dynamics) software can work in collaboration with a CAD (computer aided design) software which we also developed (VCAD: Volume CAD). So, therapeutic devices such as coils, balloons and stents could be placed in the models and CFD analysis could be performed placing devices in the models.

The flow pattern in the complicated vascular structure could be calculated such as Willis ring which has multiple inputs like ICA, VA and multiple outlets like MCA and PCA with communicating arteries. CFD with therapeutic devices could also analysed with our system.

Stent Assisted Coil Embolization: the Treatment of Wide-necked, Dissecting, and Fusiform Aneurysms

SUMMARY

Stent assisted coil embolization is a useful therapeutic modality for wide-necked and geometrically difficult aneurysms, as the stent provide a buttress that allows for coil deposition while preventing coil haerniation into the parent vessel lumen, and placement of an endovascular stent within the parent artery across the aneurysm neck may divert the blood from the aneurysm inflow tract and promote intra-aneurysm stasis and thrombosis.We report herein a 3 patients treated with endovascular stent-assisted coil embolization for symptomatic or enlarging wide-necked, dissecting, and fusiform aneurysms of the carotid and vertebrobasilar arteries. One patient had intracranial mass effect, the second had subarachnoid haemorrhage, and the third had angiographic evidence of enlarging aneurysm. The aneurysm was located in the petrous segment of internal carotid artery in one patient and in the intracranial vertebral artery in the other two patients. For all patients, we used balloon expandable stent (such as GFX, S-670) in this technique. Complete obliteration of the aneurysms could be achieved in all cases, with preservation of distal circulation.

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.

New simple method for purification of class I alcohol dehydrogenase

AIMS

The purpose of this study was to develop a new simple method for purification of rat class I alcohol dehydrogenase (ADH, EC 1.1.1.1).

METHODS AND RESULTS

Immobilized p-hydroxyacetophenone was used as a ligand for affinity chromatography for the initial purification step after ammonium sulfate precipitation of the cytosolic fraction of rat liver. Then the eluant was separated by using ion-exchange chromatography, and homogenous class I ADH, as judged by the results of SDS-PAGE and confirmed by the results of the amino-acid sequence of peptides degraded from a 39 kDa protein, was obtained with a high yield (57%). The purified ADH showed kinetic constants of 1.3 mmol/l for Km and 62.4 per min for Kcat with ethanol as a substrate. ADH was also successfully purified from yeast by a similar method using p-hydroxyacetophenone affinity chromatography.

CONCLUSIONS

This simple method involving only two chromatographic procedures may be very useful for purification of ADH.

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.

An intelligent catheter system robotic controlled catheter system

SUMMARY

We have developed a novel catheter system, an intelligent catheter system, which is able to control a catheter by an externally-placed controller. This system has made from master-slave mechanism and has following three components; 1) a joy stick as a master (for operators) 2) a catheter controller as a slave (for a patient), 3) a micro force sensor as a sensing device. This catheter tele-guiding system has abilities to perform intravascular procedures from the distant places. It may help to reduce the radiation exposures to the operators and also to help train young doctors.

Gene transfer for experimental saccular aneurysms

SUMMARY

Reinforcing an aneurysmal wall is one possible way to prevent from aneurysm rupture. We preliminarily tried focal gene transfer against the wall of experimental aneurysms to aim the transgene remodeling of aneurysmal wall. Two experimental saccular aneurysms were created on canine common carotid artery with an artificial dissecting method, which resemble clinical aneurysms. Adenovirus vector (AxCALacZ, 10(8) pfu) was slowly injected into the aneurysm cavity for over 30 minutes under the condition of intraaneurysmal flow arrest using balloon-assisted neck-plasty technique. The arteries and aneurysms were evaluated 48 hours after the transduction with X-gal staining, and beta-galactosidase expression was detected mainly in the intima in both cases. No adverse effects on the normal carotid wall and no systemic complications were observed after the procedure. This experimental study suggests the possibility of gene therapy for cerebral aneurysms.

Hemodynamic changes in drainage systems following treatment of cerebral arteriovenous malformations

SUMMARY

The authors studied 61 patients undergoing effective embolization for cerebral arteriovenous malformations (AVMs) and analyzed the hemodynamic changes in their drainage systems following embolization. The changes were classified into following 5 types: type A, disappearance of all the draining veins; type B, disappearance of a part of the cortical veins; type C, disappearance of a part of the deep-seated veins; type D, combined type Band C patterns; type E, disappearance of reflux into normal cortical veins. Each case was evaluated on the basis of these criteria from comparing pre- and post-embolization angiograms. The delay and reduction of shunt were observed in all cases. Forty-nine of them showed obvious hemodynamic changes in the draining systems including type A change in 9, type B in 19, C in 5, Din 3 and E in 13 cases, respectively. Two cases showed a spontaneous shift in the dominance of the main drainers. Thirteen of 15 cases showing successful results in subsequent radiosurgery exhibited various changes in draining pattern. Changes in drainage systems may be affected by the compartmentalization of the nidus, reduction in shunt flow, and spontaneous or progressive thromboses. These can be promoted by embolization and may be regarded as one of the indicators of successful pretreatment for radiosurgery.

Remote Manipulation of Guidewire Using a Virtual Reality Device

A trial of remote manipulation for micro guidewire is reported. The system had master-slave style. When an operator manipulated the virtual torque device at the master side, a machine at the distant slave side reproduced the manipulation. At the same time, the operator could feel the force feedback from the manipulation at the slave. We could experimentally realize this remote manipulating system using a virtual reality device.

Curative treatment of central hemangioma in the mandible by direct puncture and embolisation with n-butyl-cyanoacrylate (NBCA)

Management of central hemangioma in the mandible is difficult because of the abundant vascular network in this region. One of the most common signs of these patients, especially in the mixed dentition period, is hypermobility of the teeth with spontaneous hemorrhage from the surrounding gingival sulcus. Various therapeutic modalities have been considered, but surgery is the most frequently used. In cases of a large extensive lesion, however, intralesional injections of sclerosing agents have often been successful. A case of central hemangioma of the mandible with arteriovenous malformations in a 10-year-old girl is reported. She was treated with direct injection of an embolic material, n-butyl-cyanoacrylate, which brought satisfactory results. Preoperative embolisation of feeder vessels with Gelfoam and Avitene soaked in thrombin together with this direct injection is a safe treatment modality that is as effective as surgery.

Daunorubicin inhibits gene expression of cyclooxygenase-2 in vascular smooth muscle cells

Daunorubicin (0.1-1 microM) concentration-dependently inhibited prostacyclin production induced by interleukin-1beta (IL-1beta, 2.5 ng/ml) in cultured aortic smooth muscle cells isolated from rats. IL-1beta stimulation caused activation of nuclear factor-kappaB (NF-kappaB) and expression of cyclooxygenase-2 (COX-2) mRNA and protein, which were inhibited by daunorubicin. However, COX activity, evaluated by conversion of exogenous arachidonic acid to prostacyclin, was not affected by daunorubicin (0.1-1 microM). Protein expression of COX-1 and NF-kappaB was not affected by daunorubicin. Daunorubicin also inhibited nitric oxide (NO) production induced by IL-1beta. These results suggest that daunorubicin attenuated prostacyclin synthesis through inhibiting expression of COX-2 mRNA, which could be explained by perturbation of NF-kappaB activation.

Endovascular trapping of giant serpentine aneurysms by using Guglielmi detachable coils: successful reduction of mass effect. Report of two cases

Giant serpentine aneurysms (GSAs) are defined as partially thrombosed giant aneurysms with persistent serpentine vascular channels. Surgical management of these rare lesions is difficult because of their large size, complex structure, and unique hemodynamics. The authors report two cases of patients harboring GSAs with mass effect, which were managed effectively with endovascular treatment. The first patient was a 48-year-old man who presented with left homonymous hemianopsia caused by a GSA involving the terminal portion of the right internal carotid artery. The second patient, a 10-year-old boy, presented with tetraparesis from compression of the cervicomedullary junction by a GSA of the right vertebral artery. In each case, after confirming collateral flow by temporarily occluding the proximal artery, the aneurysm was trapped by placement of Guglielmi detachable coils at the sites at which the serpentine channels entered and exited the aneurysm. The midportion of each channel was isolated completely without packing, to maximize resorption of the devascularized mass. Mass effect and clinical symptoms rapidly improved in both cases, with no associated morbidity. We recommend endovascular trapping as a safe and effective therapeutic option for GSAs.

The selection and result of AVM treatment

The treatment selection for cerebral arteriovenous malformation (AVM) still is in controversy. In order to find out the best way to treat AVM, we summarized the treatment result of AVM patients in our hospital. Sixty-three AVM patients who had been treated at Nagoya University Hospital since 1988 to 1997 were studied. The patient characteristics were nearly the same as other reported series. The treatment modalities include surgery, embolization and radiosurgery. Rate of nidus disappearance was assessed in each treatment. Highest rate was observed in surgery or surgery with embolization. But new neurological deficits were seen in 37% of the patients of same group. Nidus occlusion rate was not high in radiosurgery with embolization, but low in complication rate. The result showed the importance of embolization procedure in the treatment selection of AVM. The value of functional MRI as pre-therapeutic study is high in those patients whose AVM adjacent to eloquent area.

Embolization of arteriovenous malformations prior to radiosurgery

SUMMARY

Embolization prior to radiosurgery is useful to reduce the AVM nidus for adequate planning for radiosurgery. In 37 cases we encountered, patients with the least radiosurgical effects had diffuse type nidus, where the feeders embolized with absorbable embolic materials had the possibility of recanalization. The main purpose of embolization is to prevent bleeding while the radiosurgical effects are being fully obtained. Thus, nidus embolization and the occlusion of fistulous feeders, meningeal feeders and intranidal aneurysms using permanent embolic materials are essential, since effective and successful embolization can increase the occlusion rate and shorten the period until complete occlusion following radiosurgery.

Usefulness of intravascular Doppler flow measurements in cerebral endovascular treatment. A comparison with trans cranial Doppler

SUMMARY

Measurement of cerebral blood flow in cerebral endovascular procedures is useful for the assessment of treatment effects. We used transcranial Doppler sonography (TCD) and Doppler guide wires (SmartWire((R)), Cardiometries Co.) in intravascular treatment. The cases were 6 brain arteriovenous malformations (AVM), 2 carotid cavernous fistulas (CCF), 2 facial angiomas, and 2 carotid stenoses. Intravascular cerebral blood flow measurements with the SmartWire were performed during the endovascular procedure. TCD was used pre- and post-endovascular treatment, and velocity, pulsatility index (PI) and resistance index (RI) were compared with the SmartWire. For both TCD and Smart Wire, blood velocity of the main artery decreased, and PI and RI were improved after embolisation of AVM. In angioplasty cases, post stenotic flow velocity, as measured by SmartWire, was improved, and the flow of MCA measured with TCD was also improved after treatment. The SmartWire is useful to assess cerebral blood flow changes during the neuroendovascular procedure. Combined with repeated follow up with TCD, Doppler flow measurements are useful to assess the effect of endovascular treatment.

Effectiveness and pitfall of embolization of cerebral arteriovenous malformations

We studied the course ofperisurgical complications of 66 AVMs and discussed the approapriate precautions. Of 66 patients with AVMs, 14 underwent postembolization surgical removal, and 43 underwent radiosurgery. Four patients were cured with total occlusion of their AVM by embolization alone. 48 patients achieved a more than 70% occlusion of the nidus. We observed 12 complications including 3 permanent and 9 temporary. Four complications occurred immediately after the embolization due to overembolization or thromboembolism, and 7 were observed several hours later which might have been caused by retrograde thrombosis or a chemical reaction to the glue. While presurgical embolization deepseated feeders must be embolized along with fistulous or high-flow feeders, 4 cases of 2nd embolization following radiosurgery showed that meningeal feeders developed or recanalized in cases embolized with absorbable particles. Thus, preradiosurgically, fistulous and meningeal feeders should be treated, and the nidus must be packed with embolic materials with no risk of recanalization. Successful nidus packing performed in 10 AVMs yielded a further nidus reduction before radiosurgery. The intranidal aneurysms which pose a high risk of rebleeding were also embolized. In order to avoid complications in the embolization of AVM, the angioarchitecture, hemodynamics and the relationship to brain function should be well recognized by preoperative functional imaging and superselective angiograms, and adequate embolic materials should be properly injected. As an embolization strategy, the priority of the target feeders should depend on the treatment to follow, and aggressive embolization of risky feeders or causing abrupt hemodynamic change should be avoided.

Embolization of cerebral arteriovenous malformations to enhance the success of subsequent radiosurgery

SUMMARY

We studied angiographic changes in embolized arteriovenous malformations (AVMs) by comparing pre- and postembolization angiograms and angiograms preceding radiosurgery. This study sought factors determining the usefulness of embolization as a pretreatment to enhance the success of subsequent radiosurgery. Thirty patients with cerebral AVMs treated in this manner over 4 years were studied. In these cases AVMs were embolized with cyanoacrylate and were treated with Gamma-knife radiosurgery. The mean size of the AVM nidus was reduced by a fraction of seven following embolization. The subsequent angiogram for planning radiosurgery showed further nidus reduction in 10 AVMs, no change in 12, and regrowth in 8. In all size-reduction cases the nidus was sufficiently packed, and 2 AVMs had thrombosed completely before radiosurgery. All the regrowing AVMs were of diffuse type; 6 were associated with already-developed leptomeningeal channels, and the remaining 3 were fed by newly sprouted meningeal feeders. Five AVMs disappeared following radiosurgery, all representing size-reduction or nochange cases. Analysis of cases with regrowth showed increased risk of that event with feeder occlusion of a multi-axially supplied AVM, lack of reduction of shunt flow, or remaining meningeal feeders. On the other hand, when embolization as pretreatment prior to radiosurgery succeeds in producing a small, compacted, plexiform nidus with slow shunt flow, it furthers the likelihood of successful radiosurgery. Nidus embolization and occlusion of fistulous and meningeal feeders are mandatory, while proximal feeder occlusion and use of embolic materials which risk recanalization should be avoided to prevent nidus regrowth.

Oral glucose retention, saliva viscosity and flow rate in 5-year-old children

There are significant differences of glucose retention in site-specificity and individuals. Sixty-two 5-year-old nursery schoolchildren participated in this study on the relation between the viscosity of saliva and flow rate and glucose retention. Each child was instructed to rinse his/her mouth with a glucose solution (0.5 M, 5 ml) and then to spit out. Three minutes after rinsing, glucose retention was determined. Resting saliva was collected by a natural outflow method, then the flow rate was determined. A rotational viscometer was used to determine the viscosity. Glucose retention and flow rate were correlated at the left maxillary primary molars, and glucose retention and viscosity were correlated at the maxillary central primary incisors. It was concluded that glucose retention after glucose mouth rinsing was site-specific, and that glucose retention and the index of decayed, missing and filled primary teeth (dmft) were slightly correlated with the salivary viscosity and flow rate.

Embolisation of cerebral arteriovenous malformations to assure successful subsequent radiosurgery

This study investigated the angiographic changes in embolised arteriovenous malformations (AVMs) pre- and post-embolisation and preradiosurgery to clarify the usefulness of embolisation as a pretreatment for radiosurgery and the strategy of embolisation for the radiosurgical success. A total of 37 patients with cerebral AVMs treated over a period of 4 years was investigated. All the AVMs were embolised with N-butyl cyanoacrylate and 2 months later they were treated by radiosurgery. The size of AVM nidus reduced just following the embolisation (mean 21.9 ml to 3.9 ml). The angiogram taken in preparation for radiosurgery showed a further size reduction in the nidus of 16 AVMs, no change in 10 and regrowth in 11. In all the cases where size was reduced, the nidus was densely packed, while all the regrown AVMs were of the diffuse type. Five AVMs disappeared following radiosurgery, all of which were size-reduction or no-change cases. In conclusion, to achieve success in subsequent radiosurgery, nidus embolisation and the occlusion of fistulous and meningeal feeders are mandatory. Imprudent proximal feeder occlusion and the use of embolic materials with a risk of recanalisation should be avoided to prevent regrowth of the nidus, which may lead to errors in planning the radiosurgery to follow.

Cerebral oxygenation state in childhood moyamoya disease: a near-infrared spectroscopy study

Near-infrared spectroscopy was used to measure the relative concentration changes of oxygenated hemoglobin (HbO(2)), deoxygenated hemoglobin (HbR), and total hemoglobin (t-Hb) before, during, and after hyperventilation in eight patients with childhood moyamoya disease who underwent surgery. The patients were divided into the following two groups: those with and those without re-build-up phenomenon on electroencephalography. All patients except one exhibited decreased concentrations of HbO(2) and t-Hb during hyperventilation and decreased concentrations of HbO(2) and increased concentrations of HbR after hyperventilation. The difference between the hemoglobin concentration during and after hyperventilation was significantly greater in the group with the re-build-up phenomenon than the group without it (P <0.03, Mann-Whitney U test). The patients with the re-build-up phenomenon had lower HbO(2) and higher HbR concentrations after hyperventilation. The concentrations of HbO(2) and HbR reflect an alteration in the oxygenated blood supply and/or oxygen use. Thus, it is strongly suggested that regional cerebral hypoxia and metabolic oxygen disturbances play an important role in the occurrence of the re-build-up phenomenon. Near-infrared spectroscopy is a useful noninvasive method to evaluate the efficacy of surgical treatment in childhood moyamoya disease.

Comparison of clinical results between GDC treatment and direct surgery for ruptured cerebral aneurysms

We present a comparison of clinical results between GDC treatment and direct surgery for ruptured cerebral aneurysms. From May 97 to April 98, 32 aneurysms were treated by direct surgery (DS) or GDC treatment. Treatments were selected depending on the clinical grade, degree of hematoma and anatomical aspect of the aneurysms. There were 13 GDC treated cases and 19 direct surgery cases. In GDC cases, there were acute stage embolization for ruptured basilar aneurysm, recurrence of case after clipping for BA-SCA aneurysm, advanced age cases, and systemic complication cases. Glasgow outcome scale (GOS) in GDC cases were 8 GR, 2 MD and 3 SD. GOS in direct surgery cases were 7 GR, 4 MD, 4 SD and 4 deaths. Cases of severe subarachnoid hemorrhage with hematoma influenced the high death rate in direct surgery group. There were three complications associated with the procedure in the GDC group, however, the rate improved after advancement of the procedure. In conclusion, GDC treatment for ruptured cerebral aneurysm was satisfactorily acceptable compared to the results of direct surgery, however, more cases will be needed for precise comparison.

Endovascular treatment of unruptured vertebro-basilar aneurysms

We reviewed 201 unruptured vertebro-basilar aneurysms encountered at our institute and 35 affiliated hospitals over the past 8 years. Of these, 106 aneurysms in 103 patients were treated with surgical or endovascular approaches: 43 aneurysms, surgically with clipping or wrapping; and 63 endovascularly with embolization. Outcome was excellent or good in 87 patients (84.5%). Among 24 patients with 36 complications, 16 had unfavorable outcomes including five deaths. Twelve patients (27.9%) with surgical treatment and two (3.3%) with endovascular treatment had unfavorable results because of treatment-related complications. Two patients with surgical treatment had complications related to perioperative management. Vascular occlusive complications were likeliest to occur in surgically treated basilar artery aneurysms (41%). Among surgically treated aneurysms the vertebral artery site was relatively associated with cranial nerve injuries. Complications numbered 36, occurring in 24 patients and 54% of complications affected outcome. Overall morbidity and mortality of surgical treatment were 18.6% and 7.0%, respectively, while those of endovascular treatment were 5.0% and 3.3%. In conclusion, complications of surgery tend to be serious and affect outcome, and endovascular treatment is safer than surgical for vertebro-basilar aneurysms. Embolizations are particularly advantageous for patients who are poor surgical risks.

Intra-arterial vein bypass using a vein-loaded stent system to occlude wide-necked aneurysms: an experimental study in dogs

We treated 13 experimental wide-necked aneurysms of lateral type produced in dog carotid arteries with a vein-loaded stent system consisting of an autologous vein graft, a vein-carrier stent, and two other self-expanding Z-shaped stents. The vein-loaded stent, made by connecting the autologous vein graft to the vein-carrier stent, was implanted in the common carotid artery to seal the aneurysm's orifice, after which two booster stents were deployed. The distal stent was placed to fix the distal end of the vein graft, and the proximal stent was placed at the proximal venous portion of the vein-loaded stent to reinforce its proximal end. In this manner an intra-arterial bypass was established across the aneurysm. Of 13 aneurysms seven were completely occluded, preserving the parent artery. The remaining six procedures resulted in parent artery occlusion because of failures in stent deployment. Angiograms performed in within 1 week six successfully treated dogs revealed the parent artery to be patent in four but thrombosed in two. Histological study of successful cases showed as smooth intima with slight endothelial hypertrophy and partially organised thrombus. The intraluminal features were also observed with a vascular endoscope at the time of treatment in four dogs and at the time of follow-up angiography in two. The appearances corresponded well to the macroscopic findings in the specimens. Our vein-loaded stent system offers complete closure of the orifice, which does not occur with conventional stent placement. The method is believed to show clinical promise for treating wide-necked aneurysms not curable by embolisation of the sac.

Experimental creation of fusiform carotid artery aneurysms using vein grafts in rats

OBJECTIVE

We developed an in vivo model of growing fusiform aneurysms, using vein grafts to the rat carotid artery. This aneurysm model might demonstrate the pathological features of the development and growth of aneurysms to become giant aneurysms.

METHODS

Placement of an interposed femoral vein graft to restore carotid artery flow was performed in Wistar rats. On Day 21, 75% of the grafts (mean diameter, 1.6 mm) were found to be dilated to resemble fusiform aneurysms (mean diameter, 5.82 mm), and 53% of these were giant. Quantitative analysis of the histological findings was performed using image-analyzing software.

RESULTS

Histological findings were similar to those for human intracranial giant aneurysms. The average length of the initial grafts in the aneurysm group was 9.1+/-1.9 mm, and grafts were significantly longer and more tortuous than in the normal graft group (6.4+/-0.8 mm) (P = 0.01). Cross-sectional areas of the aneurysms (mean, 18.9 mm2) were significantly correlated with the following: 1) the area of intra-aneurysmal thrombosis (mean, 11.1 mm2) (P < 0.0001); 2) the number of intrathrombotic vascular channels (P = 0.005); and 3) the area of dissection, with hemorrhage, between the thrombus and the wall of the aneurysm (mean, 0.72 mm2) (P = 0.0013). Scanning electron microscopic examination showed evidence of endothelial damage associated with growth of the aneurysms.

CONCLUSION

Recurrent hemorrhaging from intrathrombotic vascular channels caused dissection between the thrombus and the aneurysm wall, which led to growth of the experimental aneurysms to giant aneurysms. With this model, we demonstrated the growth mechanism of giant fusiform aneurysms.

Vein-loaded stent system to occlude wide-necked aneurysms

SUMMARY

We devised a vein-loaded stent system to immediately close the aneurysmal orifice without interrupting the parent arterial flow. Ten experimental widenecked aneurysms located on canine common carotid arteries were treated with the implantation of a newly modified vein-loaded stent system. After deploying the stent, half of them were managed under administration of 50 mg of ticlopidine hydrochloride per day and the other half followed up without any anticoagulation therapy. Immediately after the stent placement, all aneurysms were completely obliterated with patency of the parent artery in the successfully implanted vessels in both groups. Follow-up angiography one week later disclosed complete occlusion of the aneurysm with patency of the parent artery in 67% (2/3) of the group with ticlopidine, while none of the group without drugs showed patency of the parent artery. The rate of patency of the parent artery was found to be improved by administration of ticlopidine, but was still lower than that of a conventional stent. Further modifications will be needed before clinical use.

Intravascular Treatment for Cerebral Aneurysms

We have treated 142 aneurysms with intrasaccular or parent artery occlusions. Selective intrasaccular occlusions were attempted on 109 cases. Total or subtotal saccular occlusion was achieved in 93 of 96 cases. Intrasaccular occlusion could not be achieved in 13 cases because of various reasons such as wide neck, branching from aneurysmal dome, difficult to catheterize, and aneurysm too small. Parent artery occlusion was attempted on 33 cases. Twenty-five patients had giant aneurysms of the internal carotid artery (ICA) at the cavernous portion. The rest of this group had dissecting or fusiform aneurysms of the vertebral artery. Parent artery occlusion was achieved in 30 cases with six ischemic symptoms. High percentage of occlusion rate and low morbidity and mortality for metallic coil embolization prove the efficacy of this endovascular treatment.