The Enantioselective Synthesis of Eburnamonine, Eucophylline, and 16'-epi-Leucophyllidine.

A synthetic approach to the heterodimeric bisindole alkaloid leucophyllidine is disclosed herein. An enantioenriched lactam building block, synthesized through palladium-catalyzed asymmetric allylic alkylation, served as the precursor to both hemispheres. The eburnamonine-derived fragment was synthesized through a Bischler-Napieralski/hydrogenation approach, while the eucophylline-derived fragment was synthesized by Friedländer quinoline synthesis and two sequential C-H functionalization steps. A convergent Stille coupling and phenol-directed hydrogenation united the two monomeric fragments to afford 16'-epi-leucophyllidine in 21 steps from commercial material.

Design and synthesis of novel δ opioid receptor agonists with an azatricyclodecane skeleton for improving blood-brain barrier penetration.

We designed and synthesized novel δ opioid receptor (DOR) agonists 3a-i with an azatricyclodecane skeleton, which was a novel structural class of DOR agonists. Among them, 3b exhibited high values of binding affinity and potent agonistic activity for the DOR that were approximately equivalent to those of 2 which bore an oxazatricyclodecane skeleton. In vitro assays using the blood-brain barrier (BBB) permeability test kit supported the idea that 3b achieved an excellent BBB permeability by converting an oxygen atom of 2 to a carbon atom (methylene group) in the core skeleton. As a result, 3b showed potent antinociceptive effects.

Novel delta opioid receptor agonists with oxazatricyclodecane structure showing potent agonistic activities.

We recently reported oxazatricyclodecane derivatives 1 as δ opioid receptor (DOR) agonists having a novel chemotype, but their DOR agonistic activities were relatively low. Based on the working hypothesis that the dioxamethylene moiety in 1 may be an accessory site and that it may interfere with the sufficient conformational change of the receptor required for exerting the full agonistic responses, we designed and synthesized new oxazatricyclodecane derivatives 2-4 lacking the dioxamethylene moiety. As we expected, the designed compounds 2-4 showed pronouncedly improved agonistic activities for the DOR. Compound 2a with the 17-cyclopropylmethyl substituent was a potent agonist with the highest selectivity for the DOR and was expected to be a lead compound for novel and selective DOR agonists.

Human nitrilase-like protein does not catalyze the hydrolysis of vildagliptin.

Nitrilase, which is found in plants and many types of bacteria, is known as the enzyme that catalyzes hydrolysis of a wide variety of nitrile compounds. While human nitrilase-like protein (NIT), which is a member of the nitrilase superfamily, has two distinct isozymes, NIT1 and NIT2, their function has not been well understood. In this study, we investigated whether human NIT1 and NIT2 are involved in the hydrolysis of drugs using vildagliptin as a substrate. We performed Western blot analysis using human liver samples to examine protein expression of human NIT in the liver, finding that human NIT1 and NIT2 were highly expressed in the liver cytosol. We established stable single expression systems of human NIT1 and NIT2 in HEK293 cells to clarify the contribution of human NIT to hydrolysis of vildagliptin. Although the formation of a carboxylic acid metabolite of vildagliptin (M20.7) was observed in human liver samples, M20.7 was not formed by incubating vildagliptin with HEK293 cells expressing human NIT1 or NIT2. This suggests that human NIT1 or NIT2 is not involved in the metabolism of vildagliptin. Further investigation using other drugs is needed to clarify the contribution of human NIT to drug metabolism.

Novel delta opioid receptor agonists with oxazatricyclodecane structure.

We synthesized compounds 4a,c-f,h,i containing the oxazatricyclodecane structure from a novel rearrangement reaction product 2a. All the prepared compounds 4a,c-f,h,i exhibited full agonistic activities for the δ opioid receptor (DOR). Among them, the N-methyl derivative 4c was highly selective, and the most effective DOR agonist in functional assays. Subcutaneous administration of 4c produced dose-dependent and NTI (selective DOR antagonist)-reversible antinociception lacking any convulsive behaviors in the mice acetic acid writhing tests. The N-methyl derivative 4c is expected to be a promising lead compound for selective DOR agonists with a novel chemotype.

Prognostic value of pretreatment 18F-FDG PET/CT parameters including visual evaluation in patients with head and neck squamous cell carcinoma.

OBJECTIVE: The purpose of this study was to determine whether pretreatment quantitative and visual parameters seen on PET/CT using (18)F-FDG add prognostic information for clinical staging in patients with head and neck cancer. MATERIALS AND METHODS: We enrolled 108 patients with histologically proven oral, oropharyngeal, hypopharyngeal, and laryngeal squamous cell carcinomas who underwent FDG PET/CT before treatment and, later, definitive therapy in our study. PET/CT parameters-maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and uptake pattern (sphere-shaped or ring-shaped)-were recorded. The prognostic value of these parameters was evaluated using univariate and multivariate Cox regression analyses. RESULTS: In the univariate analysis, all of the FDG PET/CT parameters--SUVmax (> 10 g/mL) of the primary tumor, MTV (> 20 cm(3)), TLG (> 70 g), and uptake pattern (ring-shaped)--were significantly associated with negative effects on disease-specific survival (DSS) and disease-free survival (DFS). In the multivariate analysis, the MTV and uptake pattern remained associated with DSS after corrections for the Union for International Cancer Control (UICC) stage and definitive therapy (p = 0.023 and < 0.001, respectively). Another multivariate model that included MTV as a continuous variable, uptake pattern, and UICC stage showed that the uptake pattern remained significantly associated with DSS, whereas the association between DSS and MTV was not significant (p < 0.001 and = 0.332, respectively). CONCLUSION: Our data indicate that the pretreatment PET/CT parameters had prognostic value. In particular, a qualitative factor, uptake pattern, provided better prognostic information to the clinical staging of head and neck squamous cell carcinomas than the other PET/CT parameters.

A multicenter brain perfusion SPECT study evaluating idiopathic normal-pressure hydrocephalus on neurological improvement.

PURPOSE: This study was designed to investigate the specific cerebral blood flow (CBF) pattern in patients with idiopathic normal-pressure hydrocephalus (iNPH) and a predictive value for shunt responsiveness in a multicenter study (Study of Idiopathic Normal-Pressure Hydrocephalus on Neurological Improvement: SINPHONI). METHODS: Eighty-four iNPH patients underwent shunt operations using MRI selection criteria from the SINPHONI and were subjected to CBF single photon emission computed tomography (SPECT). The perfusion patterns on SPECT were classified: anterior-dominant CBF reduction type (A type), posterior-dominant CBF reduction type (P type), and mixed or diffuse CBF reduction type (M type). The predictive value of the CBF pattern for favorable shunt outcome was evaluated. RESULTS: Favorable outcomes were obtained in 76% (64/84) of patients, and shunt responsiveness was achieved in 85% (71/84) of patients. Areas of severely reduced relative CBF were demonstrated around the corpus callosum and in the sylvian fissure area, which included the effects of dilatations of the ventricles and sylvian fissures and relatively increased perfusion in the medial and lateral frontal, parietal, and occipital areas at high convexity. Forty-nine (58%) cases were A type, 25 (30%) cases were M type, and 10 (12%) cases were P type. A, M, and P type cases exhibited 83, 84, and 90% positive predictive values for shunt responsiveness, respectively. Mean modified Rankin scale and Mini-Mental State Examination scores of the A type group were significantly better than those of other groups. CONCLUSION: The iNPH patients showed various patterns of CBF reduction, but there was no significant difference in the predictive value among the three patterns, though CBF reduction patterns may suggest a severe condition of iNPH.

Clinical value of FDG-PET for preoperative evaluation of endometrial cancer.

OBJECTIVE: Whole body positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) has been widely used in various malignancies, but the clinical value of FDG-PET for endometrial cancer has not been fully investigated. The purpose of this study was to evaluate the usefulness of FDG-PET for preoperative evaluation of endometrial cancer. METHODS: Forty female patients suspected of having endometrial cancer were included in this study. All patients underwent an FDG-PET or PET/CT scan, and images were interpreted visually. The diagnostic performance in detecting the primary tumor, regional nodal status, and distant metastasis was determined. In addition, the usefulness of PET was assessed in terms of additional information and clinical impact for therapeutic management. RESULTS: Of 40 patients, 30 were histologically confirmed to have endometrial cancer. The patient-based sensitivity and specificity of FDG-PET for primary tumors were 83 and 100%, respectively, and 100 and 100%, respectively, for nodal metastases. There were 12 distant metastases in 6 patients and two second primary cancers in two patients, which were all accurately diagnosed by PET on a patient-basis. PET yielded 12 additional findings in 10 patients, and had a bearing on the therapeutic management of four patients, including one patient with recurrent breast cancer. CONCLUSIONS: FDG-PET had a reasonably high diagnostic accuracy in endometrial cancer. Although the number of cases with clinical impact was limited, additional information by PET was obtained in one-third of the cases.

Multicenter evaluation of a standardized protocol for rest and acetazolamide cerebral blood flow assessment using a quantitative SPECT reconstruction program and split-dose 123I-iodoamphetamine.

UNLABELLED: SPECT can provide valuable diagnostic and treatment response information in large-scale multicenter clinical trials. However, SPECT has been limited in providing consistent quantitative functional parametric values across the centers, largely because of a lack of standardized procedures to correct for attenuation and scatter. Recently, a novel software package has been developed to reconstruct quantitative SPECT images and assess cerebral blood flow (CBF) at rest and after acetazolamide challenge from a single SPECT session. This study was aimed at validating this technique at different institutions with a variety of SPECT devices and imaging protocols. METHODS: Twelve participating institutions obtained a series of SPECT scans on physical phantoms and clinical patients. The phantom experiments included the assessment of septal penetration for each collimator used and of the accuracy of the reconstructed images. Clinical studies were divided into 3 protocols, including intrainstitutional reproducibility, a comparison with PET, and rest-rest study consistency. The results from 46 successful studies were analyzed. RESULTS: Activity concentration estimation (Bq/mL) in the reconstructed SPECT images of a uniform cylindric phantom showed an interinstitution variation of ±5.1%, with a systematic underestimation of concentration by 12.5%. CBF values were reproducible both at rest and after acetazolamide on the basis of repeated studies in the same patient (mean ± SD difference, -0.4 ± 5.2 mL/min/100 g, n = 44). CBF values were also consistent with those determined using PET (-6.1 ± 5.1 mL/min/100 g, n = 6). CONCLUSION: This study demonstrates that SPECT can quantitatively provide physiologic functional images of rest and acetazolamide challenge CBF, using a quantitative reconstruction software package.

Drug design and synthesis of a novel kappa opioid receptor agonist with an oxabicyclo[2.2.2]octane skeleton and its pharmacology.

A conformational analysis of kappa opioid receptor agonists, TRK-820 and U-50,488H indicated an active conformation of TRK-820 in which the C-ring was in the boat form with the 14-OH interacting with the amide nitrogen. Based on the obtained active conformation of TRK-820, we designed and synthesized a novel kappa agonist KNT-63 with oxabicyclo[2.2.2]octane skeleton. KNT-63 showed profound antinociceptive effects via the kappa receptor which were as potent as that of TRK-820.

Quantitative mapping of basal and vasareactive cerebral blood flow using split-dose 123I-iodoamphetamine and single photon emission computed tomography.

A new method has been developed for diffusible tracers, to quantify CBF at rest and after pharmacological stress from a single session of dynamic scans with dual bolus administration of a radiotracer. The calculation process consisted of three steps, including the procedures of incorporating background radioactivity contaminated from the previous scan. Feasibility of this approach was tested on clinical SPECT studies on 16 subjects. Two sequential SPECT scans, 30 min apart, were carried out on each subject, after each of two split-dose administrations of 111 MBq IMP. Of these, 11 subjects received acetazolamide at 10 min before the second IMP injection. Additional PET scans were also carried out on 6 subjects on a separate day, at rest and after acetazolamide administration. The other 5 subjects were scanned only at rest during the whole study period. Quantitative CBF obtained by this method was in a good agreement with those determined with PET (y(ml/100 g/min)=1.07x(ml/100 g/min)-1.14, r=0.94). Vasareactivity was approximately 40% over the whole cerebral area on healthy controls, which was consistent with a literature value. Reproducibility of CBF determined in the rest-rest study was 1.5+/-5.7%. Noise enhancement of CBF images, particularly the second CBF, was reduced, providing reasonable image quality. Repeat assessment of quantitative CBF from a single session of scans with split-dose IMP is accurate, and may be applied to clinical research for assessing vascular reactivity in patients with chronic cerebral vascular disease.

Renal circulatory effects of acetazolamide in patients with essential hypertension.

BACKGROUND: Reports indicate that acetazolamide (ACZ) induces the vasodilation of all vessels in animal models, as well as in small and medium kidney vessels in animal models. However, the effect of ACZ on the renal circulation of patients with essential hypertension remains unknown. In this study we examined the effects of a carbonic anhydrase inhibitor, acetazolamide (ACZ), on the renal circulation of patients with essential hypertension. METHODS: We directly infused 1000 mg of ACZ into the main renal arteries of 10 patients with essential hypertension who had undergone cardiac catheterization. We then evaluated the effects of ACZ upon heart rate, renal artery blood pressure (BP), renal artery cross-sectional area, renal Doppler blood flow velocity, renal blood flow (RBF), and renal vascular resistance (RVR). RESULTS: The infusion of ACZ was not associated with any significant changes in heart rate or in systolic or diastolic BP. However, the velocity-time integral was increased by 11.1% +/- 7.2%, from 17.6 +/- 1.8 to 20.0 +/- 3.7 cm (P = .009); RBF was increased by 39% +/- 21%, from 300 +/- 43 to 422 +/- 96 mL/min/m(2) (P = .002); and RVR was reduced by 38% +/- 20% from 24,351 +/- 2,291 to 17,651 +/- 2,731 dynes.sec.cm(-5) (P < .01). In contrast the cross-sectional area of the renal artery did not change. CONCLUSIONS: The results of the present study demonstrated that ACZ has a potent vasodilatory effect on the renal circulation of patients with essential hypertension, leading to an obvious decrease in RVR and an increase in RBF.

[Acute brain infarction clearly demonstrated by using the three-dimensional stereotactic surface projections (3D-SSP) of 99mTc-HMPAO SPECT].

We report a 66-year-old ambidextrous man who suddenly developed aphasia seven days after coronary artery bypass grafting surgery. CT scan performed 30 minutes after onset failed to depict acute ischemic lesion. MR imaging could not be performed because of intrathoracic wires. An emergent angiogram demonstrated filling defect in the right precentral artery territory. Transaxial images of 99mTc-HMPAO SPECT showed hypoperfusion areas in the right frontal and left temporo-parietal regions. Using the three-dimensional stereotactic surface projections (3D-SSP) of 99mTc-HMPAO SPECT, we could clearly detect a sharply demarcated ischemic area which was later confirmed to be an infracted lesion in the follow-up CT. 3D-SSP, thus, appears to be useful for identifying acute infarction in such cases that MRI is impermissible.

Circulating CD34-positive cells provide an index of cerebrovascular function.

BACKGROUND: Increasing evidence points to a role for circulating endothelial progenitor cells, including populations of CD34- and CD133-positive cells present in peripheral blood, in maintenance of the vasculature and neovascularization. Immature populations, including CD34-positive cells, have been shown to contribute to vascular homeostasis, not only as a pool of endothelial progenitor cells but also as a source of growth/angiogenesis factors at ischemic loci. We hypothesized that diminished numbers of circulating immature cells might impair such physiological and reparative processes, potentially contributing to cerebrovascular dysfunction. METHODS AND RESULTS: The level of circulating immature cells, CD34-, CD133-, CD117-, and CD135-positive cells, in patients with a history of atherothrombotic cerebral ischemic events was analyzed to assess possible correlations with the degree of carotid atherosclerosis and number of cerebral infarctions. There was a strong inverse correlation between numbers of circulating CD34- and CD133-positive cells and cerebral infarction. In contrast, there was no correlation between the degree of atherosclerosis and populations of circulating immature cells. Analysis of patients with cerebral artery occlusion revealed a significant positive correlation between circulating CD34- and CD133-positive cells and regional blood flow in areas of chronic hypoperfusion. CONCLUSIONS: These results suggest a possible contribution of circulating CD34- and CD133-positive cells in maintenance of the cerebral circulation in settings of ischemic stress. Our data demonstrate the utility of a simple and precise method to quantify circulating CD34-positive cells, the latter providing a marker of cerebrovascular function.

Gated myocardial SPECT to predict response to beta-blocker therapy in patients with idiopathic dilated cardiomyopathy.

UNLABELLED: Because of the difficulty of predicting the response of patients with idiopathic dilated cardiomyopathy (IDC) to beta-blocker therapy, this study was performed to evaluate whether gated myocardial SPECT (gated SPECT) could be useful for predicting that response. METHODS: We performed gated SPECT with (99m)Tc-sestamibi on 38 patients with IDC before treatment with a beta-blocker and standard medication. Perfusion abnormalities, left ventricular (LV) function, and spheric distortion were assessed by a quantitative software program. RESULTS: We classified patients into 2 groups according to improvement in LV function after 4 mo of therapy. The groups consisted of 16 poor responders whose LV ejection fraction (LVEF) increased less than 10% and 22 good responders whose LVEF increased by 10% or more. The patient characteristics before therapy, including LV volume and LVEF, did not significantly differ between the 2 groups, but the size of the myocardial perfusion defect and spheric distortion were significantly greater in poor responders than in good responders. CONCLUSION: Gated SPECT, by allowing simultaneous assessment of perfusion, function and geometry, might be useful for predicting the response of patients with IDC to beta-blocker therapy.

Database of normal human cerebral blood flow, cerebral blood volume, cerebral oxygen extraction fraction and cerebral metabolic rate of oxygen measured by positron emission tomography with 15O-labelled carbon dioxide or water, carbon monoxide and oxygen: a multicentre study in Japan.

Measurement of cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO(2)) by positron emission tomography (PET) with oxygen-15 labelled carbon dioxide (C(15)O(2)) or (15)O-labelled water (H(2)(15)O), (15)O-labelled carbon monoxide (C(15)O) and (15)O-labelled oxygen ((15)O(2)) is useful for diagnosis and treatment planning in cases of cerebrovascular disease. The measured values theoretically depend on various factors, which may differ between PET centres. This study explored the applicability of a database of (15)O-PET by examining between-centre and within-centre variation in values. Eleven PET centres participated in this multicentre study; seven used the steady-state inhalation method, one used build-up inhalation and three used bolus administration of C(15)O(2) (or H(2)(15)O) and (15)O(2). All used C(15)O for measurement of CBV. Subjects comprised 70 healthy volunteers (43 men and 27 women; mean age 51.8+/-15.1 years). Overall mean+/-SD values for cerebral cortical regions were: CBF=44.4+/-6.5 ml 100 ml(-1) min(-1); CBV=3.8+/-0.7 ml 100 ml(-1); OEF=0.44+/-0.06; CMRO(2)=3.3+/-0.5 ml 100 ml(-1) min(-1). Significant between-centre variation was observed in CBV, OEF and CMRO(2) by one-way analysis of variance. However, the overall inter-individual variation in CBF, CBV, OEF and CMRO(2) was acceptably small. Building a database of normal cerebral haemodynamics obtained by the(15)O-PET methods may be practicable.

Extracorporeal double filtration plasmapheresis in acute atherothrombotic brain infarction caused by major artery occlusive lesion.

Extracorporeal double filtration plasmapheresis (EDFP) can quickly lower plasma viscosity and fibrinogen concentration. EDFP has the potential to improve cerebral microcirculation in acute ischemic stroke and ultimately to salvage penumbral tissue. However, no evidence is available to show that EDFP can increase cerebra blood flow (CBF). Therefore, we investigated whether EDFP could increase CBF by quantitative CBF measurements and documented the clinical effects of EDFP in acute ischemic stroke. EDFP was performed ten times in seven patients diagnosed as having acute atherothrombotic brain infarction caused by major artery occlusive lesion. They also fulfilled one of the following entry criteria: 1) diffusion/perfusion mismatch demonstrated by MRI on admission; 2) a hemispheric syndrome, but only a small lesion on diffusion weighted MRI (<25% of MCA territory); or 3) progressing stroke. Exclusion criteria were 1) contraindication of heparin or 2) spontaneous improvement of symptoms. Time from stroke onset to EDFP varied from 5 hr to 7 days. Plasma viscosity was quickly lowered by EDFP without affecting RBC counts, Hb, or Hct in all patients. Positron emission tomography (PET) with 15-O labeled H2O measurements revealed a significant CBF increase from 36.4 +/- 8.3 ml/100 g/min to 40.7 +/- 6.8 ml/100 g/min in the affected hemisphere (P=0.048). Definite CBF improvement was also demonstrated by single photon emission computed tomography (SPECT) in one of two patients who had severe stenosis of the middle cerebral artery. Furthermore, this patient showed remarkable improvement of hemiplegia immediately following EDFP (NIHSS score: 18 to 13). In conclusion, EDFP can increase CBF in ischemic brain tissue in acute atherothrombotic brain infarction. Further clinical studies should focus on the efficacy of EDFP on outcome of patients with this stroke subtype.

A theoretical model of oxygen delivery and metabolism for physiologic interpretation of quantitative cerebral blood flow and metabolic rate of oxygen.

The coupling of cerebral blood flow (CBF) and metabolic rate of oxygen (CMRO2) during physiologic and pathophysiologic conditions remains the subject of debate. In the present study, we have developed a theoretical model for oxygen delivery and metabolism, which describes the diffusion of oxygen at the capillary-tissue interface and the nonlinear nature of hemoglobin (Hb) affinity to oxygen, allowing a variation in simple-capillary oxygen diffusibility, termed "effective oxygen diffusibility (EOD)." The model was used to simulate the relationship between CBF and CMRO2, as well as oxygen extraction fraction (OEF), when various pathophysiologic conditions were assumed involving functional activation, ischemia, hypoxia, anemia, or hypo- and hyper-capnic CBF variations. The simulations revealed that, to maintain CMRO2 constant, a variation in CBF and Hb required active change in EOD. In contrast, unless the EOD change took place, the brain allowed small but significant nonlinear change in CMRO2 directly dependent upon oxygen delivery. Application of the present model to quantitative neuroimaging of CBF and CMRO2 enables us to evaluate the biologic response at capillary level other than Hb- and flow-dependent properties of oxygen transport and may give us another insight regarding the physiologic control of oxygen delivery in the human brain.

Visualization of interscapular brown adipose tissue using (99m)Tc-tetrofosmin in pediatric patients.

UNLABELLED: Brown adipose tissue (BAT) is a site of nonshivering thermogenesis in mammals. The mitochondria of BAT operate in an uncoupled mode and increase fatty acid oxidation to produce heat at birth. Thus, the BAT of human infants and children contains more active mitochondria than that of adults. We surmised that because (99m)Tc-tetrofosmin can be absorbed by functional mitochondria in the myocardium and in tumor cells, it could reveal mitochondrial function in BAT. METHODS: Between January 1999 and December 2002, we retrospectively analyzed 385 consecutive studies of (99m)Tc-tetrofosmin uptake in pediatric patients with cardiac disorders. All patients with symmetric (99m)Tc-tetrofosmin accumulation within the neck and shoulder region according to planar images were selected, and the features of the uptake were analyzed. RESULTS: Increased symmetric (99m)Tc-tetrofosmin uptake in the interscapular BAT was a typical profile of 65 of the 385 patients (17%). The frequency of (99m)Tc-tetrofosmin uptake was significantly higher in winter than in spring or summer (P < 0.05) and prominent in newborns. The frequency peaked between 0 and 2 y of age and then declined with age. CONCLUSION: Gamma-camera imaging with (99m)Tc-tetrofosmin can reveal interscapular BAT distribution in infants and children in terms of mitochondrial activity.