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.

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.

(2)H-decoupling-accelerated (1)H spin diffusion in dynamic nuclear polarization with photoexcited triplet electrons.

In dynamic nuclear polarization (DNP) experiments applied to organic solids for creating nonequilibrium, high (1)H spin polarization, an efficient buildup of (1)H polarization is attained by partially deuterating the material of interest with an appropriate (1)H concentration. In such a dilute (1)H spin system, it is shown that the (1)H spin diffusion rate and thereby the buildup efficiency of (1)H polarization can further be enhanced by continually applying radiofrequency irradiation for deuterium decoupling during the DNP process. As experimentally confirmed in this work, the electron spin polarization of the photoexcited triplet state is mainly transferred only to those (1)H spins, which are in the vicinity of the electron spins, and (1)H spin diffusion transports the localized (1)H polarization over the whole sample volume. The (1)H spin diffusion coefficients are estimated from DNP repetition interval dependence of the initial buildup rate of (1)H polarization, and the result indicates that the spin diffusion coefficient is enhanced by a factor of 2 compared to that without (2)H decoupling.

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.

Cerebrovascular occlusion by catheterization and embolization: clinical experience.

Intravascular occlusion by various catheterization techniques was used to treat 27 cases of carotid-cavernous fistula, giant intracavernous aneurysm, and cerebral or dural arteriovenous malformation. Several case reports are presented. The detachable balloon technique proved valuable in the treatment of traumatic carotid-cavernous fistula and giant aneurysm. Calibrated-leak balloon catheterization with fluid embolization was used to treat cerebral arteriovenous malformation. Selection of embolic material is discussed.

Evaluation of particulate embolic materials with MR imaging, scanning electron microscopy, and phase-contrast microscopy.

PURPOSE: To analyze the properties and embolic effect of microfibrillar collagen (MFC), Gelfoam powder, and polyvinyl alcohol (PVA) materials that are used in embolization procedures in the head and neck. METHODS: The shape and surface of these embolic agents were examined with scanning electron microscopy and phase-contrast microscopy. The mean number of areas of T2-weighted high signal intensity was measured on MR images in a rat embolization model to estimate the embolic effect. RESULTS: By scanning electron microscopy and phase-contrast microscopy, MFC appears fibriform and has various sizes and an irregular surface. Gelfoam is of uniform size and has a smooth surface. PVA materials are granulated and have a rough surface. MFC is somewhat suspendable and its shape changes moderately after suspension. Gelfoam is very suspendable and its shape changes rapidly. PVA showed only mild swelling. The embolic effect of MFC was the lowest of the materials examined. Large PVA particles (250 to 500 microns) showed a lesser embolic effect than Gelfoam or small PVA particles (50 to 150 microns) or medium-sized PVA particles (150 to 250 microns). No significant differences were observed among the embolic effects of Gelfoam, small PVA particles (50 to 150 microns), and medium PVA particles (150 to 250 microns). CONCLUSIONS: MFC and large PVA particles (250 to 500 microns) should be used for embolization of vascular anatomy involving potentially dangerous anastomoses. Gelfoam, PVA particles of 150- to 250-micron diameter, and PVA particles of 50- to 150-micron diameter are adequate for embolization involving homogeneous and peripheral anatomy.

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.

Pineal Tumors: clinical diagnosis, with special emphasis on the significance of pineal calcification.

The clinical presentations, findings of neuroradiological examinations, laboratory findings, pathological diagnoses, methods of treatment, and results of follow-up of 43 cases of pineal tumor collected at the Nagoya University Hospital from 1958 to 1979 are reviewed. The definitions of calcification of the pineal body and of pineal tumor are given. There is a significant difference in the incidence of calcification of the pineal body between pineal teratomas and pineal germinomas. Although there is a 100% rate of calcification of the pineal body in cases of pineal germinoma, the rate is very low in cases of pineal teratoma; calcification appears in only a small percentage of the cases of teratoma mixed with germinoma or embryonal carcinoma, or both. In male patients with suprasellar germinoma, there is a high frequency of an associated pineal calcification. No pineal calcification is seen in cases of basal ganglia germinoma. The computed tomographic (CT) findings of pineal teratoma and germinoma are characteristic. CT scanning is superior for early diagnosis of suprasellar and basal ganglia germinomas.

Myeloma manifesting as a large jugular tumor: case report.

The authors report a case of cranial plasmacytoma with multiple myelomas and palsy of the lower cranial nerves. The osteolytic lesion adjacent to the jugular foramen was demonstrated by an angiogram to be exceedingly hypervascular, with arteriovenous shunting resembling that seen in paragangliomas. Forty-five cases of cranial and intracranial plasmacytoma from the literature were reviewed. The findings indicate that a cranial plasmacytoma commonly appears to be a hypervascular tumor, whereas most dural tumors or intraparenchymal tumors have poor vascularity.

Histopathological study of balloon embolization: silicone versus latex.

Bilateral, symmetrical, experimental aneurysms were produced with anastomosed vein flap in the carotid arteries of 24 mongrel dogs. Aneurysms were occluded with latex or silicone balloons on each side and observed angiographically from 2 weeks to 2 months. A histopathological study was performed subsequently using light and scanning electron microscopy. Rupture after balloon embolization occurred in five aneurysms; all of which were incompletely occluded by a silicone balloon. On subsequent angiograms, four silicone balloons and one latex balloon were found to have migrated into the aneurysm, resulting in aneurysmal expansion. Parent artery occlusion was more common with latex balloons than silicone balloons. Histopathologically, residual fresh thrombi, decreased proliferation of fibroblasts within the aneurysmal cavity, and poor endothelialization were present around the silicone balloon. These results suggest that the intra-aneurysmal organization, as seen in the aneurysm occluded by the silicone balloon, will be delayed because the balloon is not fixed within the aneurysm, and that this free-floating and rotating balloon causes repeated trauma to the aneurysm wall, contributing to subsequent enlargement and rupture of the aneurysm. The superior antithrombogenic nature of silicone may be responsible for the bias of such phenomena toward the silicone balloon.

Primary choroid plexus papilloma located in the suprasellar region: case report.

A 34-year-old woman with primary choroid plexus papilloma occurring in the suprasellar region is reported. No connection with the ventricular system was found during intraoperative observations. The findings of pathological examinations such as hematoxylin and eosin staining, transthyretin (prealbumin) immunoreactivity, and electron microscopy were consistent with choroid plexus papilloma. Radiologically, it was extremely difficult to differentiate from tuberculum sellae meningioma. To our knowledge, this is the first case of primary choroid plexus papilloma in this location reported in the literature.

Surgical treatment for pediatric moyamoya disease: use of the superficial temporal artery for both areas supplied by the anterior and middle cerebral arteries.

OBJECTIVE: To revascularize ischemic territories of both the anterior cerebral artery (ACA) and the middle cerebral artery (MCA), a simple and effective combined bypass operation was performed in 36 pediatric patients with moyamoya disease during the past 8 years. METHODS: The branches of the superficial temporal artery (STA) were used to revascularize the ACA and MCA territories. In children older than 5 years, the parietal branch of the STA was usually used for an end to side anastomosis with a cortical branch of the MCA. In children who were younger than 5 years, the parietal branch of the STA was used for an encephaloduroarteriosynangiosis instead of a direct anastomosis. Encephaloduroarteriosynangiosis, using the proximal part of the intact frontal branch of the STA, and encephalomyosynangiosis, using the temporal muscle, were also performed in all patients to stimulate spontaneous anastomosis. In addition, bilateral frontal burr holes were made in all patients to induce vascularization of the ACA territories from the distal part of the intact frontal branch of the STA. The first operation was performed on the dominant side, then a similar procedure was performed on the opposite side after an interval of at least 3 months. RESULTS: Postoperative clinical symptoms and the findings from magnetic resonance imaging, magnetic resonance angiography, angiography, and electroencephalography demonstrated improvement in all patients. CONCLUSION: These results suggest that the placement of bilateral burr holes (while leaving the frontal branch of the STA intact), in addition to the STA-MCA anastomosis, encephaloduroarteriosynangiosis, and encephalomyosynangiosis, is very effective in vascularizing the ischemic ACA and MCA territories in pediatric patients with moyamoya disease.

Evaluation of pressure changes in feeding arteries during embolization of intracerebral arteriovenous malformations.

The pressure in 47 arteries feeding 21 arteriovenous malformations (AVM's) was investigated during transarterial embolization using a Tracker-18 microcatheter. On average, systolic pressure increased by 22 mm Hg. In AVM's with single or few feeders, embolization was usually achieved well; in contrast, giant AVM's with multiple feeders and a large arteriovenous shunt were poorly embolized. However, large AVM's with well-demarcated components may be reduced by embolization to an appropriate size for surgery or stereotactic radiation therapy. It was found that the feeding artery pressure increased significantly more in well-embolized than in poorly embolized cases. Measurements of the feeding artery pressure clarified the hemodynamics of AVM's and facilitated more successful embolization.

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.

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.

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.

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.

Fluoride profiles in dental calculus from Japanese, Chinese and British residents.

Whether the fluoride concentrations and profiles differ in human dental calculus obtained from different countries was investigated. A total of 203 dental calculus deposits on 203 permanent teeth from residents (mean age, 52.1 years) of Nagoya (Japan), Shanghai (China), Leeds (Great Britain) and the Wuhan mountainous area (China, fluoridated area) were analysed. An abrasive microsampling procedure was used to examine fluoride distribution. There were five types of fluoride profiles in dental calculus in each area/country (designated types L, J, U, T, W). In supragingival calculus, type L (highest in the outermost layers) and type J (highest in the innermost layers) both had significantly higher values than type U (high in the surface and innermost layers) but were relatively identical. In subgingival calculus, type W (high in the outermost, mid and innermost layers) was characteristics. Calculus from the Wuhan mountainous area (fluoridated) had the highest fluoride concentration, followed by Leeds (non-fluoridated), and Nagoya and Shanghai (non-fluoridated) calculus had the lowest. Fluoride concentrations in supragingival calculus were higher in teeth extracted because of periodontal diseases than dental caries. It is concluded that fluoride concentrations and distribution in dental calculus differ from country to country, probably due to different fluoride environments.

The occipital-vertebral anastomosis as a collateral pathway: hemodynamic patterns--case report.

The authors describe the case of a 67-year-old man with acquired obstruction of the common carotid artery and a large, direct occipital-vertebral artery anastomosis bridging the vertebral and carotid artery systems. They discuss the hemodynamics within this type of anastomosis in the context of cerebrovascular occlusive disease and outline their classification of the hemodynamic patterns that have been observed. Surgical procedures for occlusive disease in the presence of such anastomoses are also addressed.