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For flexible and highly ionized macromolecules such as DNA, it is important to correctly evaluate the intramolecular polarization in an induced dipole force field. In a proposed polarizable molecular block (PMB) model, a large molecule is divided into several molecular blocks. The atomic charges of the blocks are optimized by using the respective electrostatic potentials (ESPs) on the molecular surface. By using the capped hydrogen removal operation, the total charge of the blocks is controlled exactly to have an integer charge. The atomic polarizabilities of the blocks are optimized by using the respective polarized one-electron potentials that are the differences between ESPs with and without an external test charge. Induced dipole-charge interactions between the blocks are all included, but those interactions within the blocks are strictly excluded. All dipole-dipole interactions are included, but the damping functions are applied to the close dipole-dipole pairs. Several types of damping (simple scaling, exponential, linear, and Gaussian) are evaluated. The validity of the PMB model was verified by using trinucleotide duplexes which have A-, B-, and Z-DNA forms. The reference energies of trinucleotide duplexes including counterions (GGT3Na-ACC3Na, GAC3Na-GTC3Na, and GCG3Na-CGC3Na) are calculated using ωB97XD/aug-cc-pVDZ. All damping types reproduced well the reference interaction energies, dipole moments, and ESPs. Among them, the simple scaling with strong attenuation to 1-2 atomic pairs showed the highest stability against the polarization catastrophe. This study shows that it is possible to develop a high-quality polarizable force field by treating the intramolecular polarization on a block-by-block basis.

BACKGROUND If complete obliteration of ruptured pediatric arteriovenous malformation (AVM) cannot be achieved, the appropriate follow-up duration and predictors of rebleeding remain unknown. OBSERVATIONS Pediatric patients with ruptured AVMs admitted to the authors’ hospital within the past 30 years were evaluated. Rebleeding was confirmed in two patients. The first patient was a 5-year-old boy who experienced right thalamic hemorrhage. AVM was found in the bilateral thalamus and treated with stereotactic radiosurgery (SRS). New aneurysm formation and residual AVM regrowth were confirmed 21 years after the SRS. Eight months later, rebleeding occurred. The second patient was a 5-year-old boy who underwent removal of a left cerebellar hemorrhage and AVM. The residual AVM was treated with SRS. Residual AVM regrowth was detected at 6 years 7 months after SRS. Five months later, new aneurysm formation was confirmed. Two additional days later, rebleeding occurred. LESSONS New aneurysm formation and residual AVM regrowth may predict rebleeding and can occur >20 years after the initial rupture and treatment. If AVM obliteration is not achieved, long-term follow-up is needed, even in adulthood, with attention to new aneurysm formation and residual AVM regrowth. Further treatment is recommended if these findings are confirmed.

Background The occurrence of sacral dural arteriovenous fistula (dAVF) is rare. The detailed vascular architecture of sacral dAVF, including 3-dimensional (3D) angiographic images with operative findings, has not been evaluated compared with that of the thoracic and lumbar levels. We report a case of sacral dAVF with 3D angiographic examination and operative findings, with a literature review. Case Description A 60-year-old man presented with progressive urinary incontinence and gait disturbance. A sacral dAVF was detected at the S1-2 level. The shunt point was at the medial side of the line between the intermediate sacral crest and the most medial point of the L5 pedicle circle at the anterior posterior view of the angiography; we defined this type as the medial type. After embolization, latent inflow arteries were visualized ipsilaterally and contralaterally. During surgery, because of dAVF recurrence, a vascular tangle was found on the dura. The surgical interruption of the draining vein improved the patient's symptoms. From the literature review, 92% of cases had medial-type shunt point. It is possible for sacral dAVF to have multiple inflow arteries originating ipsilaterally or bilaterally, and a venous pouch. Conclusions The shunt point of sacral dAVF tended to be located medially, not in the sacral foramen. Sacral dAVF has unique angioarchitecture. The differentiation of dAVF from epidural arteriovenous fistula may not be easy in some cases of sacral lesions. Therefore, further studies with a larger number of patients focused on the detailed vascular architecture are needed.

The primary photochemical reaction of the light, oxygen, and voltage (LOV) domain of the blue-light photosensor YtvA of Bacillus subtilis were investigated using high-level QM(DFT/MRCI)/MM methods. After blue-light excitation, the Sγ atom of the reactive cysteine forms a covalent bond with the C4a of the flavin mononucleotide (FMN) ring. Two conformations for the side chain of reactive cysteine with occupancies of 70% (conf A) and 30% (conf B) are observed in the X-ray crystallographic structures of the YtvA-LOV (Moglich, A.; Moffat, K. J. Mol. Biol. 2007, 373, 112−126). In conf A, the thiol group is directed toward the dimethylbenzene moiety of the FMN ring whereas it is placed directly above the N5 atom of the FMN ring in conf B. Starting from both conformations, the singlet and triplet excited pathways were evaluated. The singlet states excited from conf A decay nonradiatively to the triplet states by intersystem crossing (ISC). After the formation of a neutral biradical, the triplet states cross over ...

BACKGROUND Intracranial Growing teratoma syndrome(iGTS) is a phenomenon in which a tumor with a teratoma component grows during treatment, and its pathological tissue is often a mature teratoma. Here we report a case of iGTS in which the timing of surgery was determined by tumor markers and changes in tumor size on MRI images. CASE-REPORT: 11-year-old boy with a short stature. He developed a headache and we found a pineal gland tumor on MRI. Due to obstructive hydrocephalus, an endoscopic third ventriculostomy and biopsy were performed. The pathological diagnosis was mature teratoma, but AFP was elevated at 104.2 ng/mL. Considering NGGCT, we started chemoradiation immediately. Despite the declining AFP, it gradually increased, at which point we suspected iGTS. Resection was considered, but at some point tumor growth had stopped, so radiation therapy and a second course of ICE therapy preceded the resection. Thereafter, the tumor was completely removed, and a third course of ICE therapy was performed. DISCUSSION The onset mechanism of iGTS has not been elucidated, and its prediction is difficult. Early resection of the tumor is required, but discontinuation of radiation therapy and side effects of chemotherapy also need to be considered. In our case, resection was performed after normalization of AFP and recovery of myelosuppression. The patient followed an uneventful course, but the timing of resection was controversial. CONCLUSION We experienced a case of iGTS in NGGCT, a mixed tumor with mature teratoma. The optimal timing of the resection was discussed and literature was reviewed.

Gliosarcomas are a variant of glioblastomas and present a biphasic pattern, with coexisting glial and mesenchymal components. In this study, two unusual cases are presented. Case 1 is a 52-year-old woman with a headache and memory disturbance for a month. Case 2 is an 18-year-old man with a headache lasting two weeks. In both cases, an MRI revealed enhancing T1-low to iso, T2-iso to high intensity lesions in the pineal gland region. Histologically, in case 1, the tumor showed spindle cell proliferation with disorganized fascicles and cellular pleomorphism. Tumor cells variously exhibited oncocytic transformation. Immunohistochemically, most of the spindle tumor cells were positive for myoglobin and desmin. Some of the tumor cells were positive for GFAP and S-100 protein. On the other hand, all tumor cells were positive for CD133, Musashi1, and SOX-2 which are the markers of neural stem cells. In case 2, the tumor showed monotonous proliferation of short spindle cells with disorganized fascicles and cellular atypism. The morphological distinction between glial and mesenchymal components was not apparent. Immunohistochemically, most of the spindle tumor cells were positive for desmin. Glial tumor cells that were dispersed within the sarcoma as single cells were positive for GFAP. In addition, all tumor cells were positive for CD133, Musashi1 and SOX-2. Based on these microscopic appearances, and immunohistochemical findings, these cases were diagnosed as gliosarcomas arising from the pineal gland region. These results also indicated that pluripotential cancer stem cells differentiated into glial and muscle cell lines at the time of tumor growth. In a survey of previous publications on gliosarcoma arising from the pineal gland, these cases are the second and third reports found in English scientific writings.

Polarized one-electron potential (POP) optimization is a powerful and practical method to determine multicenter dipole polarizabilities that can be used for constructing polarizable force fields. The POP optimization is similar to the widely used electrostatic potential (ESP) optimization to determine the partial charges of molecules. However, while the ESP optimization targets the electrostatic potentials on a molecular surface, the POP optimization targets the change of electrostatic potentials on molecular surfaces which are induced by the field of a test charge on the molecular surface. Since only additional one-electron integrals for the test charge are required for the estimation of the surface potentials, the change of electrostatic potentials has been named "polarized one-electron potentials". We show that in the POP optimization, both an explicitly interacting polarizability model and an implicitly interacting polarizability model can be used for the determination of the multicenter polarizabilities. In the explicitly interacting model, intramolecular induced dipole-induced dipole interaction is mutually included in the process of the POP optimization, but the interaction is not included in the implicitly interacting model. In the implicitly interacting polarizability model, a combined model of isotropic atom polarization and anisotropic bond polarization is shown to provide the best fitting results for nucleic acid bases which show large polarization anisotropy. A simple scaling model to the chemical bond has been newly proposed for the explicitly interacting polarizability model. We show that the simple model can be applied to molecular simulations without any damping of exponential type in the intramolecular induced dipole interaction. A detailed procedure for determination of the multicenter dipole polarizability by the POP optimization is also presented.

Gliosarcomas are a variant of glioblastomas and present a biphasic pattern, with coexisting glial and mesenchymal components. In this study, two unusual cases are presented. Case 1 is a 52-year-old woman with a headache and memory disturbance for a month. Case 2 is an 18-year-old man with a headache lasting two weeks. In both cases, an MRI revealed enhancing T1-low to iso, T2-iso to high intensity lesions in the pineal gland region. Histologically, in case 1, the tumor showed spindle cell proliferation with disorganized fascicles and cellular pleomorphism. Tumor cells variously exhibited oncocytic transformation. Immunohistochemically, most of the spindle tumor cells were positive for myoglobin and desmin. Some of the tumor cells were positive for GFAP and S-100 protein. On the other hand, all tumor cells were positive for CD133, Musashi1, and SOX-2 which are the markers of neural stem cells. In case 2, the tumor showed monotonous proliferation of short spindle cells with disorganized fascicles and cellular atypism. The morphological distinction between glial and mesenchymal components was not apparent. Immunohistochemically, most of the spindle tumor cells were positive for desmin. Glial tumor cells that were dispersed within the sarcoma as single cells were positive for GFAP. In addition, all tumor cells were positive for CD133, Musashi1 and SOX-2. Based on these microscopic appearances, and immunohistochemical findings, these cases were diagnosed as gliosarcomas arising from the pineal gland region. These results also indicated that pluripotential cancer stem cells differentiated into glial and muscle cell lines at the time of tumor growth. In a survey of previous publications on gliosarcoma arising from the pineal gland, these cases are the second and third reports found in English scientific writings.

The purpose of this study was to find flavin derivatives with absorption maxima in the blue-green region of the visible spectrum that might be used as alternative cofactors in blue-light photoreceptors. To this end, the vertical absorption spectra of eight lumiflavin-related compounds were calculated by means of quantum chemical methods. The compounds differ from lumiflavin by the subsitution of an S atom for an O atom at the 2- and/or 4-positions of the isoalloxazine core, the substitution of an N atom for a CH group in the 6- and/or 9-positions, or an extension of the π system at the 7- and 8-positions. For the three most promising compounds, 2-thio-lumiflavin, 4-thio-lumiflavin, and 2,4-dithio-lumiflavin, the quantum chemical investigations were extended to include geometry relaxations in the excited states, rates for spin-forbidden transitions and an estimate of spectral shifts brought about by polar protic environments. We find these thiocarbonyl compounds to have very promising excited-state properties. They absorb in the blue-green wavelength regime around 500 nm, i.e., substantially red-shifted with respect to lumiflavin that is the cofactor of natural blue-light photoreceptors. Their triplet quantum yields are predicted to be close to unity while their triplet lifetimes are long enough to enable bimolecular photochemical reactions. The combination of these properties makes the thioflavins potentially suitable candidates as cofactors in biomimetic photoswitches.

A polarizable model potential (PMP) function for methanol and three ions (Cl-, Na+, and Mg2+) is developed on the basis of high-level ab initio molecular orbital calculations (MP2/6-311++G(2d,2p)). The PMP function consists of Coulomb, polarization, and Lennard-Jones terms. The permanent partial charge parameters of the Coulomb term, and the multicenter polarizability parameters of the polarization term, are determined by using electrostatic potential optimization, and polarizable one-electron potential (POP) optimization, respectively. The Lennard-Jones parameters are adjusted to reproduce the ab initio potential energy surfaces of methanol dimer and ion−methanol complexes. The PMP function using the final parameters reproduced well the ab initio energy surfaces of methanol dimer, ion−methanol, and methanol−ion−methanol systems. The root-mean-square (rms) deviations of ion−methanol systems having various conformations are only 10−12% of the ab initio interaction energies. The electron density changes by ...

Molecular dynamics simulations were performed to investigate the stereoselective interaction between an enantiomeric amino acid substrate (N-acylated-l-phenylalanine-p-nitrophenyl ester) and an l-histidine-containing dipeptide catalyst (Nα-(N-benzyloxycarbonyl-l-leucyl)-l-histidine) in the bilayer of cationic surfactants (N,N-bisdodecyl-N,N-dimethylammonium chloride). We found that a catalyst–substrate complex, which had an interamide hydrogen bond, was formed spontaneously in vacuum at 500 K. This complex was found to be stable both in vacuum and in the bilayer membrane for 100 ps at 300 K. The distances between the hydrophobic side chains in the complex were consistent with experimental results. The interamide hydrogen bond was retained in the hydrophobic core of the membrane. These results suggest that the catalyst–substrate complex found in this work is relevant to the stereoselective hydrolysis of the l-enantiomer of the substrate.

The ab initio polarized one-electron potential method has been previously used to determine multicenter dipole polarizabilities of molecules with success. This method is used here to demonstrate the transferability in the multicenter polarizabilities of methane, ethane, propane, n-butane, water, methanol, ethanol and propanol. Three classical models of atom, bond and combined atom-bond polarizability are investigated. The near-transferability of the multicenter polarization parameters is found in these three models. The qualitative correspondence between theoretical and empirical approaches is also shown for the atom and bond polarizabilities.

Multicenter polarizabilities and first hyperpolarizabilities of acetylene, ethylene, ethane and benzene are evaluated by using ab initio MP2 polarized one-electron potentials for developing a reliable and simple polarizable potential. Combination of classical isotropic induced dipoles at atom centers with anisotropic induced dipoles along bonds is recommended for describing a strong and inhomogeneous field, which often encounters in molecular dynamics simulations of solutions including ions and biological systems.

Carrageenan is known to change its conformation from coil to helix and to form a gel. However, the accurate conformation and the transition mechanism have not yet been detailed. In this work, the conformational behavior of β-carrageenan (a copolymer with a carrabiose repeating unit, 1,4-linked 3,6-anhydro-α-D-galactose (A) and 1,3-linked β-D-galactose (B)), was studied by using molecular mechanics and molecular dynamics simulation methods with the program CHARMM22. The energy maps of the carrabiose as a function of the dihedral angles of the glycosidic linkages between the A–B (1–3 linkage) and B–A (1–4 linkage) carrabiose units were calculated. Both carrabiose units were found to have five deep potential energy minima. Based on these carrabiose conformations, 25 conformers of the single helical chain carradodecaose were constructed and their minimum energy conformations were investigated by molecular mechanics and molecular dynamics simulations. From the results of these analyses, a possible single helic...

To clarify the relationship between delayed neuronal death and apoptosis, we made an attempt to detect DNA strand breaks in the gerbil hippocampal CA1 pyramidal neurons following transient ischemia by an in situ DNA double strand breaks staining. The condensed nuclei of neurons in CA1 were occasionally seen and positively stained 3 days after ischemia. The degenerating dark neurons with condensed nuclei in CA1 markedly increased in number and were clearly stained for DNA strand breaks 5 days after ischemia, whereas normal-looking nuclei remained unstained. No neurons were stained in other hippocampal subfields and dentate gyrus. The present study strongly indicates that the CA1 pyramidal neurons die through an apoptotic process.

多糖カラギーナンの溶液中での構造を計算機実験により明らかにしていく試みの第一歩としてκ-カラギーナンの構成糖である3, 6-anhydroα-D-galactoseとβ-D-galactose 4-sulphateを用いて, それらの4, 1, 1, 3結合二糖についての分子力学・分子動力学計算を行った. グリコシル結合の二面角φ, ψを変えて作成したエネルギー図より1, 3結合においては二面角が比較的自由に動き得る広い低エネルギー領域があることがわかった. しかし硫酸基を除くとこの領域はφ=171°, ψ=188°の近傍に限定される. この領域はX線回折から得られたダブルヘリックス形成時の二面角領域と対応している. また, この領域における水分子を含めたシミュレーションでは二糖分子間に水分子を介した水素結合による架橋が見いだされた.

The electrostatic potential is usually evaluated by putting a test charge at several points on an appropriate molecular surface. The polarization effect is an indispensable long-range interaction as well as the electrostatic interaction. To evaluate the polarization effect, it is necessary to relax the wavefunction under the perturbed Hamiltonian. In the present work the polarized molecular potentials based on the ab initio SCF-CI method have been fitted by multicenter polarizabilities and hyperpolarizabilities. The polarization energies and induced dipole moments calculated by using the fitted parameters have been significantly improved by including the first hyperpolarizabilities in the case of a water molecule.

This study evaluated the usage of concentrated red cells stored in MAP solution (RC-MAP), whose stored period is extended to 42 days, in comparison with ordinary concentrated red cells (CRC). Units of discarded blood, numbers of cross-match in each lot and the duration until the use of blood after blood collection from donors were studied both in RC-MAP and CRC.Only three units (0.1%) were discarded due to the expiration of stored period in 2386 units of RC-MAP, while 81 units (5.2%) were discarded in CRC. Although mean numbers of cross-match were comparable between RC-MAP and CRC, the numbers of lot that were cross-matched more than 4 times were significantly greater for RC-MAP than CRC. In addition, the duration until the use of blood were significantly longer for RC-MAP than CRC. These results suggest that RC-MAP is more effective in the usage of red cell concentrates than CRC. Meanwhile more than 93% of RC-MAP were used within 21 days after blood collection, especially 98% of RC-MAP were used in blood type A within that period. This indicates that most of RC-MAP can be used at the time as high quality red cells. RC-MAP were also alternatively used with washed red cells or leucocyte poor red cells in case, because of its excellent removal of plasma, granulocytes and lymphocytes compared with CRC.

This study summarized the cases of autologous blood transfusion in the Akita University Hospital since 1989 and evaluated the effects of autologous blood transfusion on the usage of homologous blood for surgical procedures.A total of 279 cases were entered in the autologous blood donation programs since 1989. No homologous blood was transfused for 232 cases (83%) in total and 49 cases (68%) and 148 cases (87%) in cardiovascular surgery and orthopedic surgery, respectively. Since MAP solution has been introduced in autologous blood donation programs, leap frog or switch back method will not be applied to collect autologous blood for a long period. The MAP autologous blood donation can make the program easier. In some of the surgical procedures with predeposit autologous blood, the average units of homologous blood prepared were decreased compared with the cases without autologous blood. However, C/T ratio of homologous blood was increased in the some cases with autologous blood. In such cases, the units of MSBOS should be allocated depending on the units of autologous blood prepared.Autologous blood donation programs and the MSBOS system should be closely linked to evaluate, thus, effective blood usage can be achieved.

Carrageenan is known to change its conformation from coil to helix and to form a gel. However, the accurate conformation and the transition mechanism have not yet been detailed. In this work, the conformational behavior of β-carrageenan (a copolymer with a carrabiose repeating unit, 1,4-linked 3,6-anhydro-α-D-galactose (A) and 1,3-linked β-D-galactose (B)), was studied by using molecular mechanics and molecular dynamics simulation methods with the program CHARMM22. The energy maps of the carrabiose as a function of the dihedral angles of the glycosidic linkages between the A–B (1–3 linkage) and B–A (1–4 linkage) carrabiose units were calculated. Both carrabiose units were found to have five deep potential energy minima. Based on these carrabiose conformations, 25 conformers of the single helical chain carradodecaose were constructed and their minimum energy conformations were investigated by molecular mechanics and molecular dynamics simulations. From the results of these analyses, a possible single helic...

The empirical energy parameters for a calcium ion and its ligands in proteins were determined within a pairwise additive framework. The interaction energies of Ca2+-water, Ca2+-peptide group and Ca2+-carboxyl group systems were calculated using the ab initio molecular orbital method with basis sets of double zeta quality including polarization or diffuse functions. The resulting potential energy surfaces served as references for the determination of the nonbonded parameters in the empirical energy function. The nonadditive corrections for the Ca2+-ligand pair potentials are incorporated implicitly in the nonbonded paremeters by treating three-body (1:2 complex) or seven-body (1:6 complex) systems in reference calculations. Ligand polarizations induced by Ca2+ are estimated from the partial atomic charges of two-body (1:1 complex) systems. The charge sets were determined by scaling so as to reproduce the reference potential energy surfaces. The newly determined parameter set was used in a stochastic boundary molecular dynamics simulation of phospholipase A2. The solvated structure of the Ca2+-binding site obtained from an X-ray crystallographic study is well reproduced by the parameter set.

p K a differences between formic acid and acetic acid and between methanol and methanethiol were calculated as a sum of the acidity difference in the gas phase and the solvation free-energy difference. The ab initio molecular-orbital method with MP3/6-31+G * and/or MP4/6-31+ +G ** basis sets and the molecular-dynamics free-energy perturbation technique were applied to the studies of the acidity and solvation, respectively. The estimated value for formic acid and acetic acid was in good agreement with the experimental value within a few p K a units, but that for methanol and methanethiol was different from the experimental value by 4–6 p K a units.

Molecular-dynamic calculations predict that, if Tyr24 and Asn84 are each replaced by a Cys residue, it should be possible to form a third disulfide bond in ribonuclease T1 (RNase T1) between these residues, with only minimal conformational changes at the catalytic site. The gene encoding such a mutant variant of RNase T1 (Tyr24----Cys24, Asn84----Cys84) was constructed by the cassette mutagenesis method using a chemically synthesized gene. In order to reduce the toxic effect of the mutant enzyme (RNase T1S) on an Escherichia coli host, we arranged for the protein to be secreted into the periplasmic space by using a vector that harbors a gene for an alkaline phosphatase signal peptide under the control of the trp promoter. The nucleolytic activity of RNase T1S toward pGpC was approximately the same as that of RNase T1 at 37 degrees C (pH 7.5). Moreover, at 55 degrees C, RNase T1S retained nearly 70% of its activity while the activity of the wild-type enzyme was reduced to less than 10%. RNase T1S was also more resistant to denaturation by urea than the wild-type enzyme. However, unlike RNase T1, RNase T1S was irreversibly and almost totally inactivated by boiling at 100 degrees C for 15 min.

The transition state of acylation step of trypsin catalysis was determined by molecular orbital calculations. The calculations were carried out at the RHF-LCAO-SCF approximation level with double zeta basis set (plus polarization functions). The role of His57 residue in the acylation step of the catalytic reaction of trypsin was analysed from a quantum mechanical point of view. The influences of surrounding residues, such as oxyanion hole and Asp102-, and the electrostatic effect of the other regions of the enzyme were also studied. His57 was proved to capture the proton from Ser195 side chain terminus with its lone pair and to transfer it to substrate with electrostatic assistance of Asp102- and oxyanion hole.

Dural reconstruction is a significant problem in many cases of decompressive craniotomy and dural defect. Expanded polytetrafluoroethylene (ePTFE) sheet have been used as a dura mater substitute for duraplasty. The outcomes of 83 consecutive patients at our institution were reviewed who underwent external decompression and closure with the ePTFE sheet between August 1995 and December 2000. Eight cases of infection occurred. Seven patients had infection with subdural empyema after cranioplasty with autologous bone. Three patients improved after removal of only the infected bone. One patient improved after removal of the infected bone and ePTFE sheet. One patient experienced wound infection after the original operation. Four patients subsequently developed local and severe inflammation with skin erythema until the ePTFE sheet was removed. Four patients had severe recurrent infections which required subsequent therapy such as vascularized free rectus abdominis muscle flap transfer. Duraplasty with ePTFE sheet might promote infection and poor circulation in the skin flap. The ePTFE sheet should be removed at an early stage in a patient with infection.

A 54-year-old male with chronic renal failure due to diabetic nephropathy suffered dysphagia and left facial spasm without head trauma during a hemodialysis session. CT scan revealed a right acute epidural hematoma. MRI and cerebral angiography did not reveal any abnormalities in the intracranial vasculature. The occurrence of intracranial spontaneous epidural hematoma in a haemodialysis patient has not been reported. During hemodialysis, the intracranial pressure transiently increases and rapidly recovers. It is assumed that the decreasing intracranial pressure caused epidural hematoma.

A 52-year-old man with medical complications of diabetic mellitus and alcoholic liver dysfunction, presented with weakness in the bilateral lower extremities. Cervical magnetic resonance images disclosed the lesion extended from retropharyngeal space and multiple vertebral bodies to epidural space of the spinal canal, which was enhanced by gadolinium. Not only fever elevation during clinical course but also inflammatory reaction on selologic examination were not identified, so we initially thought the lesion metastatic spinal tumor. In researching original foci, his clinical condition worsened with gate disturbance and urinary incontinence. Eleven days later after admission, laminectomy from C-5 to Th-1 and open biopsy of the lesion was performed. The vertebral bodies exposed via the right frontal approach were covered by thick whitish membrane. Small mount of pus emerged after incision of the membrane, so we diagnosed the lesion pyogenic spondylitis. After the operation, high dose antibiotic therapy for 6 weeks was performed. Follow-up cervical MR imaging 4 months after the operation found that the volume of the lesion and compression of the spinal cord were reduced. The gate disturbance and urinary incontinence gradually improved, he was able to walk with a cane 6 months later.

A 59-year-old woman presented with a rare middle fossa dural arteriovenous fistula (AVF) unrelated to the cavernous sinus manifesting only as subarachnoid hemorrhage. Angiography revealed shunts between the meningeal branches of both the internal and external carotid arteries and the sphenobasal sinus. The AVF drained into the superficial middle cerebral vein (SMCV) which had a varix and an anastomosis to a superior cerebral vein. The arterial supply vessels were eliminated surgically and the sinus was excised. Bleeding did not recur and there was no venous infarction. Dural AVF of the sphenoparietal sinus is associated with pulsatile exophthalmos and dural AVF of the sphenopetrosal sinus with tinnitus, but dural AVF of the sphenobasal sinus has no obvious symptom. Simple interruption of the SMCV at the penetration of the arachnoid membrane was possible because of the absence of a draining vessel to preserve AVF patency, but the arteries were eliminated in this patient to prevent formation of another AVF.

We present a surgical case of a dissecting aneurysm of the middle cerebral artery associated with subarachnoid hemorrhage and intracranial hemorrhage. A 29-year-old man suddenly fell into a comatose state, and was referred to our hospital. CT scan showed diffuse subarachnoid hemorrhage and an intracerebral hematoma with marked midline shift located in the right frontal lobe. The right carotid angiogram revealed complete occlusion at the M2 portion of the middle cerebral artery, but failed to reveal any aneurysms in the rest of the intracranial circulation. We undertook emergent surgery to evacuate the hematoma and to confirm whether it was a dissecting aneurysm or not. After evacuation of the hematoma of the right frontal lobe, the Sylvian fissure was noticed to be widely opened. We detected a large dissecting aneurysm with a dark-purplish wall arising from the right M2 trunk, and we trapped the aneurysm. The postoperative course was uneventful and the patient gradually improved and was discharged without neurological deficits. We presented this case with a review of the literature.

Apoptosis occurs spontaneously in a wide variety of neoplasms. However, it is difficult to detect apoptotic cells in routine histological sections because the cells undergoing apoptosis die singly and are then rapidly phagocytosed. Since DNA fragmentation is an important hallmark of apoptosis, visualization of DNA strand breaks in tissue sections provides the means for readily identifying apoptotic cells in situ. We have applied an in situ DNA strand break staining procedure for the quantitative estimation of apoptotic cells in surgical specimens of 62 different brain tumours. Positively stained apoptotic cells were observed in 25 (40.3%) cases and their percentage (apoptotic index) ranged from 0.1 to 8.9. Both fragmented and condensed nuclei of apoptotic cells and apoptotic bodies were stained. In addition, we assessed the proliferative activity of each specimen by immunostaining with the MIB-1 antibody (MIB-1 index) which detects the cell cycle phase-dependent Ki-67 antigen. Brain tumours with higher MIB-1 indices showed a tendency to higher apoptotic indices. The results of this study indicate that apoptosis occurs spontaneously in various brain tumours.

The authors report a case of sinus pericranii in a 22-year-old female presenting with severe headache, vomiting, bradycardia, and bradypnea following excessive distention of the tumor. After tumor removal, the symptoms were completely relieved. The symptoms were thought to be due to transient impairment of blood flow in the superior sagittal sinus.

D-Helix-deleted bovine pancreatic phospholipase A2 was designed using molecular mechanic calculations, and synthesized. Effects of the deletion on the enzymatic activity and on the structure were investigated. The enzymatic activity of the mutant protein was about 40% of that of the native one for a micellar substrate of 1,2-dioctanoyl-phosphatidylcholine. Although the Michaelis constant of the mutant enzyme was not changed, the catalytic constant was decreased. The dissociation constant of calcium ion was also changed. 1H NMR study revealed a slight conformation change around the active site of the mutant enzyme in addition to changes around the mutated region. The effect on the activity of the mutation seems to be due to the conformational changes around the active site.

The charge relay hypothesis generated a large number of theoretical and experimental studies that tested the ideas involved. Opinion based upon theoretical and experimental studies is divided on the prediction, although there are many experimental data which do not support the hypothesis. The essential feature is the proton transfer from the histidine imidazole to the aspartate. Thus, we have performed the detailed calculations of the proton transfer from His 57 to Asp 102 including the environment of the couple in protonated bovine pancreatic β-trypsin. The charge state of the His 57-Asp 102 couple is greatly influenced by the environment of the enzyme around it. In this paper, it is shown that the proton between His 57 and Asp 102 is covalently bonded to the His 57 imidazole in the protonated β-trypsin. Our MO calculations, which support the neutral-pK-histidine theory as the results, do not support the charge relay mechanism.

As part of a study of the catalytic mechanism of carboxypeptidase A, two proton transfers in the system Glu 270 H 2 OZnHis 69-Asp 142 are treated with an ab initio MO method. Results show that the proton transfers are strongly affected by the environment. It is predicted that the proton between His 69 and Asp 142 is covalently bonded to His 69.

Many investigations on the reaction mechanism of carboxypeptidase A (CPA) have shown that the zinc ion and Glu 270 in the active site are important in the catalytic reaction with a peptide substrate. X-Ray crystallographic studies of native CPA showed that the zinc ion is coordinated to His 69, Glu 72, His 196, and one water molecule and that the Zn-coordinated water molecule forms a hydrogen bond with Glu 270. The zinc-water-Glu 270 system of native CPA was analyzed by the ab initio SCF-LCAO-MO method. Some ligands of zinc are included in the MO calculations as point fractional charges. The results show that the Zn-coordinated water molecule acts as a proton donor to Glu 270, and that the electrostatic effect of Zn2+ and its ligands and the electron delocalization between Zn2+ and the water play a significant role in lowering the barrier height of proton transfer. We consider that the carbonyl group of the substrate, without breaking the hydrogen bond between Glu 270 and the Zn-coordinated water molecule, points towards a fifth coordination site slightly away from Zn2+, and that the water molecule itself is modified by its connection to Glu 270 in a way that favors the reaction.