Structural basis of substrate recognition by the substrate binding protein (SBP) of a hydrazide transporter, obtained from Microbacterium hydrocarbonoxydans.

Microbacterium hydrocarbonoxydans was isolated, using hydrazide compounds as its sole carbon source. The key enzyme that metabolizes these compounds was identified as hydrazidase, and the operon containing the gene coding for the enzyme, was revealed by genome sequencing. The operon also contained genes coding for an ATP-binding cassette transporter (ABC transporter), which was expected to transport the hydrazide compounds. Substrate binding protein (SBP), a component subunit of the transporter, plays an important role in recognizing the correct substrates for transport. Therefore, to elucidate the mechanism of recognition of the unnatural hydrazide compounds, we determined the crystal structures of the SBP, obtained from M. hydrocarbonoxydans (Mh-SBP), complexed with and without the hydrazide compound, at 2.2 Å and 1.75 Å resolutions, respectively. The overall structures of Mh-SBP were similar to those of the SBP in oligopeptide transporters such as OppA. On comparison, the liganded and unliganded structures of Mh-SBP showed an open - close conformation change. Interestingly, the binding mode of the compound to Mh-SBP was almost identical to that of the compound to hydrazidase, suggesting that the ABC transporter served transporting these compounds. Furthermore, based on the hydrazide complex structure, paraben, the other putative substrate of the protein, was successfully used with Mh-SBP to obtain the paraben complex structure.

Discovery and structure-activity relationships study of positive allosteric modulators of the M3 muscarinic acetylcholine receptor.

The M3 muscarinic acetylcholine receptor (mAChR) is a member of the family of mAChRs, which are associated with a variety of physiological functions including the contraction of various smooth muscle tissues, stimulation of glandular secretion, and regulation of a range of cholinergic processes in the central nerve system. We report here the discovery and a comprehensive structure--activity relationships (SARs) study of novel positive allosteric modulators (PAMs) of the M3 mAChR through a high throughput screening (HTS) campaign. Compound 9 exhibited potent in vitro PAM activity towards the M3 mAChR and significant enhancement of muscle contraction in a concentration-dependent manner when applied to isolated smooth muscle strips of rat bladder. Compound 9 also showed excellent subtype selectivity over other subtypes of mAChRs including M1, M2, and M4 mAChRs, and moderate selectivity over the M5 mAChR, indicating that compound 9 is an M3-preferring M3/M5 dual PAM. Moreover, compound 9 displayed acceptable pharmacokinetics profiles after oral dosing to rats. These results suggest that compound 9 may be a promising chemical probe for the M3 mAChR for further investigation of its pharmacological function both in vitro and in vivo.

Two-stage operation for high cervical intramedullary ependymoma in young adult.

We describe a two-stage operation, rarely reported since being introduced in 1911, for treatment of an intramedullary ependymoma extending to the upper cervical cord in a young adult. This classic two-stage strategy combined with modern techniques remains a useful option for selected patients to safely remove intramedullary ependymomas.

Post-operative dexmedetomidine-based sedation after uneventful intracranial surgery for unruptured cerebral aneurysm: comparison with propofol-based sedation.

BACKGROUND: Clinical applications of dexmedetomidine (DEX) for neurosurgical procedures have not been adequately investigated. This study aimed to test the use of DEX infusion, alone or as an adjunct to propofol infusion, as compared to propofol infusion in patients with an unruptured cerebral aneurysm after uneventful intracranial procedures. METHODS: In this retrospective observational study from a single institute, of 184 patients who underwent uneventful intracranial procedures for an unruptured cerebral aneurysm between January 2003 and March 2007, we reviewed 50 managed with DEX-based sedation (DEX alone or as an adjunct to propofol infusion) between April 2005 and March 2007, and 50 managed with propofol-based sedation (propofol alone) between January 2003 and April 2005. With DEX-based sedation, both intubated and extubated patients received DEX infusion at an initial dose of 0.4 µg/kg/h, followed by a maintenance dose of 0.2-0.7 µg/kg/h. Propofol was used in both groups at a dose range of 0.5-5.0 mg/kg/h. Hemodynamic variables, including heart rate (HR) and blood pressure (BP), and adverse events were recorded and compared between the groups. RESULTS: HR during sedation and systolic BP at 2 h after beginning sedation were significantly lower in the DEX group. No serious adverse events were observed. In the DEX group, 66% were sedated in combination with propofol, of whom 94% were intubated. CONCLUSIONS: DEX could be used safely for both intubated and extubated patients following uneventful intracranial procedures for an unruptured cerebral aneurysm, though it significantly reduced HR. Our findings also indicate that it is preferable to add low-dose propofol to DEX for management of intubated patients.

Anterior cerebral artery notching on anterior optic pathways in a child with craniopharyngioma and progressive blindness.

We report the clinical significance of anterior cerebral artery (ACA) notching on the optic nerve and chiasm in a 3.5-year-old girl with a craniopharyngioma and progressive blindness. She presented with a headache and vomiting, followed by binocular blindness. Magnetic resonance imaging (MRI) studies demonstrated severely distended A1 segments and ill-depicted ACAs. Surgical decompression via a right subfrontal approach was performed to reverse blindness. Postoperative MRI studies showed good ACA visualization. A second operation via a right pterional approach revealed ACA notching, which appeared as a transverse groove on the right optic nerve and chiasm. ACA notching should be considered as a possible cause of progressive visual disturbance and a potential risk of ACA infarction in a child with a craniopharyngioma.

Potent and orally bioavailable CCR4 antagonists: Synthesis and structure-activity relationship study of 2-aminoquinazolines.

Starting with a series of CC chemokine receptor-4 (CCR4) antagonists developed in a previous study, the potency was improved by replacing the pyrrolidine moiety of N-(4-chlorophenyl)-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine 2 with a 3-(hydroxymethyl)piperidine. The resulting compound (1'-{4-[(4-chlorophenyl)amino]-6,7-dimethoxyquinazolin-2-yl}-1,4'-bipiperidin-3-yl)methanol 8ic was a strong inhibitor of human/mouse chemotaxis. Oral administration of 8ic showed anti-inflammatory activity in a murine model of acute dermatitis (oxazolone-induced contact hypersensitivity test) in a dose-dependent manner.

Epidermoid Cyst with Torcular Herophili Obstruction and Unusual Venous Drainage.

BACKGROUND: An epidermoid cyst arising from diploic space in the skull can cause an intracranial mass effect with compression of the underlying venous sinuses. CASE DESCRIPTION: A 66-year-old woman came to us with a persistent headache and unsteadiness. Computed tomography demonstrated an occipital bone cystic lesion with an intracranial mass effect overlying the torcular herophili, with high-intensity findings in diffusion-weighted magnetic resonance imaging. Cerebral angiogram demonstrated obstruction of the torcular herophili with development of diploic venous drainage. The patient underwent removal of the lesion and a cranioplasty procedure. The diagnosis was torcular epidermoid cyst. The postoperative course was uneventful, and the symptoms were resolved. CONCLUSIONS: Development of diploic venous drainage contributed to avoidance of critical intracranial hypertension during slow growth of a torcular epidermoid cyst.

Design, synthesis, and pharmacological evaluation of N-bicyclo-5-chloro-1H-indole-2-carboxamide derivatives as potent glycogen phosphorylase inhibitors.

As a result of the various N-bicyclo-5-chloro-1H-indole-2-carboxamide derivatives with a hydroxy moiety synthesized in an effort to discover novel glycogen phosphorylase (GP) inhibitors, 5-chloro-N-(5-hydroxy-5,6,7,8-tetrahydronaphthalen-2-yl)-1H-indole-2-carboxamide (5b) was found to have potent inhibitory activity. The introduction of fluorine atoms both at a position adjacent to the hydroxy group and in the central benzene moiety lead to the optically active derivative 5-chloro-N-[(5R)-1,3,6,6-tetrafluoro-5-hydroxy-5,6,7,8-tetrahydronaphthalen-2-yl]-1H-indole-2-carboxamide (25e(alpha), which was the most potent compound in this series (IC(50)=0.020microM). This compound inhibited glucagon-induced glucose output in cultured primary hepatocytes with an IC(50) value of 0.69microM, and showed oral hypoglycemic activity in diabetic db/db mice at 10mg/kg. Compound 25e(alpha) also had an excellent pharmacokinetic profile, with high oral bioavailability and a long plasma half-life, in male SD rats. The binding mode of 25e(alpha) to this molecule and the role of fluorine atoms in that binding were speculated in an enzyme docking study.

Discovery of potent CCR4 antagonists: Synthesis and structure-activity relationship study of 2,4-diaminoquinazolines.

A new series of quinazolines that function as CCR4 antagonists were discovered during the screening of our corporate compound libraries. Subsequent compound optimization elucidated the structure-activity relationships and led the identification of 2-(1,4'-bipiperidine-1'-yl)-N-cycloheptyl-6,7-dimethoxyquinazolin-4-amine 14a, which showed potent inhibition in the [(35)S]GTPgammaS-binding assay (IC(50)=18nM). This compound also inhibited the chemotaxis of human and mouse CCR4-expressing cells (IC(50)=140nM, 39nM).

Potent CCR4 antagonists: synthesis, evaluation, and docking study of 2,4-diaminoquinazolines.

A series of CC chemokine receptor-4 (CCR4) antagonists were examined in a previous report in an attempt to improve metabolic stability in human liver microsomes. In this study, the cycloheptylamine moiety of N-cycloheptyl-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine 1 was replaced with the p-chloroaniline moiety, and the resulting compound, N-(4-chlorophenyl)-6,7-dimethoxy-2-(4-pyrrolidin-1-ylpiperidin-1-yl)quinazolin-4-amine (8c), retained its potency ([(35)S]GTPgammaS-binding inhibition and CCL22-induced chemotaxis in humans/mice). Based on the structure-activity relationships (SAR), a homology model was constructed for CCR4 to explain the binding mode of 8c. Overall, there was good agreement between the docking pose of the CCR4 homology model and the human [(35)S]GTPgammaS assay results. Administration of 8c in a murine model of acute dermatitis showed anti-inflammatory activity (oxazolone-induced contact hypersensitivity test).

Involvement of Ets-1 transcription factor in inducing matrix metalloproteinase-2 expression by epithelial-mesenchymal transition in human squamous carcinoma cells.

Epithelial-mesenchymal transition (EMT) is a crucial event in cancer progression. We previously reported that EMT up-regulates matrix metalloproteinase-2 (MMP-2) expression in squamous cell carcinoma (SCC) cells. In this study, we showed that Tet Off-induced expression of Snail or SIP1, and treatment with TGF-beta1 induced EMT in terms of down-regulation of E-cadherin, and up-regulation of vimentin and MMP-2 expression with morphological changes. In SCC cells, SIP1 expression was induced by Snail and TGF-beta1, but Snail expression was not induced by SIP1 or TGF-beta1. However, expression of Snail but not SIP1 was strongly increased by TGF-beta1 in highly invasive SCC cells with mesenchymal phenotypes. Analysis of the MMP-2 promoter revealed that an Ets-1 binding site, located between position -1255 and -1248 relative to the transcriptional start site, was critical for the activation by Snail, SIP1 and TGF-beta1 in SCC cells. Induced expression of Snail and SIP1 resulted in the increased expression of Ets-1 and DNA-binding activities of nuclear proteins to the Ets-1-binding site and strong Ets-1 expression was detected in highly invasive SCC cells. Furthermore, overexpression of Ets-1 induced the promoter-activation and expression of MMP-2 without EMT. These results indicate that EMT induces Ets-1 expression, which activates the MMP-2 promoter, but Ets-1 by itself has no activity to induce EMT in SCC cells.

Ruptured True Anterior Choroidal Artery Aneurysm in Cisternal Segment.

BACKGROUND: Rupture of a true anterior choroidal artery (AChA) aneurysm in the cisternal segment is extremely rare, whereas cases of a distal AChA aneurysm associated with moyamoya disease are increasingly reported. CASE DESCRIPTION: A 58-year-old woman presented with a severe headache and vomiting. Computed tomography demonstrated a subarachnoid hemorrhage without intraventricular or intracerebral hemorrhaging. Cerebral angiogram findings revealed a proximal AChA aneurysm mimicking an internal carotid artery aneurysm at the origin of the AChA. Intraoperative findings demonstrated a ruptured aneurysm located on a bend of the proximal AChA in the carotid cistern. Neck clipping of the aneurysm with preservation of the AChA led to a good outcome. CONCLUSIONS: A rare case of ruptured true AChA aneurysm in the cisternal segment, unrelated to moyamoya disease, is presented as a cause of subarachnoid hemorrhage.

De Novo Aneurysm Associated with Superficial Temporal Artery to Middle Cerebral Artery Bypass: Report of Two Cases and Review of Literature.

BACKGROUND: De novo aneurysm formation has been reported as a rare complication of superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery. CASE DESCRIPTION: The first patient with intracerebral hemorrhage had a ruptured de novo aneurysm arising from the recipient MCA at 6 years after undergoing STA-MCA bypass for hemispheric hemodynamic insufficiency. In the second case, an enlarging unruptured STA aneurysm was detected by follow-up magnetic resonance angiography at 8 years after the patient underwent STA-MCA bypass for moyamoya disease. Both patients were successfully treated by surgical clipping. CONCLUSIONS: Persistent hemodynamic stress with hypertension in an artificial T-shaped vasculature and traumatic injury during surgical manipulation are the most important causes for de novo aneurysms after STA-MCA bypass. Follow-up magnetic resonance and computed tomography angiography examinations, along with appropriate blood pressure control, are recommended for patients who have undergone STA-MCA bypass surgery.

Increased invasion and matrix metalloproteinase-2 expression by Snail-induced mesenchymal transition in squamous cell carcinomas.

Loss of E-cadherin expression is a major characteristic of highly invasive and metastatic cancers. Epithelial-mesenchymal transition (EMT) has been advocated to be a causative mechanism for the suppression of E-cadherin and tumor progression. Snail is a zinc finger transcription factor that triggers the EMT and is one of the recently identified E-cadherin repressors. The reverse correlation of Snail and E-cadherin expressions has been reported in many types of human cancers including squamous cell carcinoma (SCC). In this study, we showed that three E-cadherin negative SCC cell lines had a fibroblastic morphology, strong expressions of vimentin, a mesenchymal marker gene, and Snail. Compared to other E-cadherin positive SCC cells, these cells showed higher invasive ability and expression of MMP-2, a matrix degrading enzyme which has been demonstrated to be highly expressed in invasive cancer cells. Over-expression of Snail in A431 cells resulted in the loss of E-cadherin expression, the change of their morphology to fibroblastic, and the up-regulation of vimentin gene expression, indicating that an EMT was induced by Snail. Furthermore, these cells became more invasive and showed higher levels of MMP-2 activity and its gene expression. Luciferase analysis demonstrated that the MMP-2 promoter activity was induced by Snail transfection and the promoter region from -262 to -411 relative to the transcriptional start site was necessary for this induction. These results indicate that Snail is a new inducer of MMP-2 expression and suggest that the EMT contributes to the increased invasion not only through the inhibition of cell-cell adhesion but also the up-regulation of MMP-2 expression in SCC cells.

Clear cell ependymoma with a lipidized component that developed in the thoracic spinal cord.

The authors report a case of clear cell ependymoma with a lipidized component that developed in the thoracic spinal cord. A 59-year-old man was admitted to the hospital with an itchy pain in the left forearm to the left anterior and lateral chest for the past three years. Neurological findings on admission included dissociated sensory disturbance below the C8 level and increased deep tendon reflex in both lower extremities. An MRI scan of the spinal cord revealed an intramedullary tumor with a longer diameter of 3.5 cm at the T3-T4 level and a distended syrinx at the T2-T3 level. Surgery was performed after T1-T5 laminectomy. The gray, soft and well demarcated tumor was removed subtotally. Light microscopy revealed a portion where clear cells proliferated and a portion where foamy cells proliferated. In some tissue, there were a very few nuclear areas suggestive of a perivascular pseudorosette. Neither nuclear division nor necrosis was observed. Immunohistochemically, the tumor cells were positive for glial fibrillary acidic protein (GFAP), epithelial membrane antigen (EMA), vimentin, and negative for cytokeratin, synaptophysin. The MIB-1 staining index was 0.25%. Based on these findings, diagnosis of clear cell ependymoma with a lipidized component was made.

Obstacles encountered during transradial angiography from after Radial Artery puncture to the aortic arch.

OBJECTIVE: To elucidate the key points for safe performance of transradial angiography. CONCLUSIONS: Transradial angiography can be performed safely if attention is paid to the following points from after radial artery puncture to reaching the aortic arch: resistance during guide wire operation for sheath insertion after puncture; confirmation of the superficial brachial artery; guide wire resistance while guiding the catheter to the aortic arch; and aortic arch anomalies.