Cortical thickness and hippocampal shape in pure vascular mild cognitive impairment and dementia of subcortical type.

BACKGROUND AND PURPOSE: The progression pattern of brain structural changes in patients with isolated cerebrovascular disease (CVD) remains unclear. To investigate the role of isolated CVD in cognitive impairment patients, patterns of cortical thinning and hippocampal atrophy in pure subcortical vascular mild cognitive impairment (svMCI) and pure subcortical vascular dementia (SVaD) patients were characterized. METHODS: Forty-five patients with svMCI and 46 patients with SVaD who were negative on Pittsburgh compound B (PiB) positron emission tomography imaging and 75 individuals with normal cognition (NC) were recruited. RESULTS: Compared with NC, patients with PiB(-) svMCI exhibited frontal, language and retrieval type memory dysfunctions, which in patients with PiB(-) SVaD were further impaired and accompanied by visuospatial and recognition memory dysfunctions. Compared with NC, patients with PiB(-) svMCI exhibited cortical thinning in the frontal, perisylvian, basal temporal and posterior cingulate regions. This atrophy was more prominent and extended further toward the lateral parietal and medial temporal regions in patients with PiB(-) SVaD. Compared with NC subjects, patients with PiB(-) svMCI exhibited hippocampal shape deformities in the lateral body, whilst patients with PiB(-) SVaD exhibited additional deformities within the lateral head and inferior body. CONCLUSIONS: Our findings suggest that patients with CVD in the absence of Alzheimer's disease pathology can be demented, showing cognitive impairment in multiple domains, which is consistent with the topography of cortical thinning and hippocampal shape deformity.

Lymphscintigraphy predicts response to complex physical therapy in patients with early stage extremity lymphedema.

We investigated whether baseline lymphscintigraphic findings can predict long-term response to complex physical therapy (CPT) in patients with early stage extremity lymphedema. Twenty patients with unilateral extremity lymphedema of clinical stage I or II underwent CPT after baseline lymphscintigraphy. Therapeutic responses (good vs. poor) were evaluated at 1 year post-CPT based on changes in skin status and subjective symptoms, and percent volume reductions and compared with clinical factors and lymphscintigraphic findings. Eleven patients showed good response to CPT with significant volume reduction of edematous extremities, and no significant volume reduction was observed in the remaining 9. Patients with good or poor responses to CPT showed no significant differences in terms of clinical variables. However, significant differences were observed between the lymphscintigraphic findings of these patients. More specifically, a lymphscintigraphic finding of main lymphatic vessels without collateral lymphatic vessels was the best predictor for a good response to CPT; the sensitivity, specificity and accuracy of this lymphscintigraphic finding is 91% (10/11), 100% (9/9) and 95% (19/20), respectively. In patients with unilateral extremity lymphedema of early stage, baseline lymphscintigraphy may usefully predict long-term response to CPT.

Cell uptake and tissue distribution of radioiodine labelled D-luciferin: implications for luciferase based gene imaging.

Optical luciferase gene imaging is emerging as a method to monitor gene expression in small animals. However, there is concern over how regional availability of exogenously administered substrate may affect photon emission. We thus synthesized [125I]iodo-D-luciferin, which demonstrated substrate characteristics for firefly luciferase, and investigated its cell uptake kinetics and in vivo biodistribution. Luminescence assays of luc gene transduced cells confirmed a linear decline in emitted light units with decreasing luciferin concentration. Both luc gene transduced and control cells demonstrated a low level of cellular uptake and rapid washout of [125I]iodo-D-luciferin, although early uptake was slightly higher for transduced cells (P < 0.005). Biodistribution in ICR mice demonstrated that early uptakes in liver, lung, myocardium and muscle were lower with intraperitoneal compared to intravenous administration. In view of the poor cell uptake, uptake levels (< 3%ID/g) suggest that substrate concentration may limit light emission rates in organs such as bone, muscle, myocardium, and particularly the brain. Thus, substrate availability should be considered as a potential limiting factor for photon emission efficiency in certain organs when attempting quantitative interpretation of optical luc gene imaging.

Use of insulin to improve [18 F]fluorodeoxyglucose labelling and retention for in vivo positron emission tomography imaging of monocyte trafficking.

While 18F-FDG labelling of monocytes would allow in vivo trafficking with positron emission tomography (PET), present methods suffer from poor retention of radioactivity. We investigated the feasibility of utilizing insulin for improved [18F]fluorodeoxyglucose (18F-FDG) labelling. Separated human monocytes and lymphocytes were labelled with 18F-FDG with or without 3 h insulin pre-incubation. Insulin had no effect on lymphocyte labelling (21.4+/-0.8% vs 20.8+/-1.1% efficiency, P=NS). However, for monocytes, insulin pre-incubation led to a 169+/-9% increase in labelling efficiency (19.3+/-4.1 vs 32.5+/-1.8, P<0.05), without significant effects on cell activation or viability. Moreover, while only 57.7+/-4.8% and 40.4+/-5.6% of the 18F-FDG was retained at 1 and 3 h for controls, the retention rate increased to 91.6+/-2.1% (P=0.01) and 86.5+/-1.9% (P<0.01) after insulin pre-incubation. Improved 18F-FDG retention was accompanied by a 70.3+/-7.4% decrease in glucose-6-phosphatase activity (P=0.02). PET imaging of rats showing hepatic ischaemia-reperfusion injury demonstrated higher liver uptake for monocytes labelled after insulin treatment. Thus, insulin improves monocytic 18F-FDG uptake and retention, and may provide a feasible labelling method for PET imaging.

A simple and efficient in vitro method for metabolism studies of radiotracers.

In vitro metabolism of acetylcholinesterase inhibitors containing 3-[(18)F]fluoromethylbenzyl- ([(18)F]1) and 4-[(18)F]fluorobenzyl-piperidine moieties ([(18)F]2) was studied and compared with the in vivo metabolism. Defluorination of the [(18)F]1 mainly occurred to generate [(18)F]fluoride ion both in vitro and in vivo. In contrast, the [(18)F]2 was converted into an unknown polar metabolite in both metabolism methods and another metabolite, 4-[(18)F]fluorobenzoic acid in vitro. These results demonstrated that the in vitro method can be used to predict the in vivo metabolism of both radiotracers.

Development of a miniature scintillation camera using an NaI(Tl) scintillator and PSPMT for scintimammography.

We have developed a small scintillation camera dedicated to breast imaging and have evaluated the performance of the system. In order to increase the limited field of view (FOV) determined by the size of a position-sensitive photomultiplier tube (PSPMT), the imaging characteristics of a diverging hole collimator (DHC) were also investigated. The small scintillation camera system consists of an NaI(Tl) crystal (60 mm x 60 mm x 6 mm) coupled to a Hamamatsu R3941 PSPMT, a resistor chain circuit, preamplifiers, nuclear instrument modules, an analogue to digital converter and a PC for control and display. The intrinsic energy resolution of the system was 12.9% FWHM at 140 keV. The spatial resolution was measured using a line-slit mask and 99mTc point sources and was 3.1 mm FWHM. The intrinsic sensitivity of the system was approximately 162 counts/s kBq(-1). The DHC made it possible to image a larger FOV (75 x 75 mm2 at the surface of collimator) than a parallel-hole collimator (60 x 60 mm2). The system sensitivity obtained using the DHC gradually decreased with distance (3% at 1 cm, 6% at 2 cm and 9% at 3 cm). The results demonstrate that the system developed in this study could be utilized clinically to image malignant breast tumours. A DHC can be employed to expand the FOV of the system confined by the size of PSPMT with a modest compromise in the performance of the system.

Radiolabeling of paclitaxel with electrophilic 123I.

123I-Labeled paclitaxel, [123I]-1 was prepared by electrophilic aromatic radioiodination of 3'-N-(p-trimethylstannylbenzoyl)-3'-debenzoylpaclitaxel 2 with 123I- in the presence of peracetic acid.

Syntheses and binding affinities of 6-nitroquipazine analogues for serotonin transporter. Part 1.

6-Nitroquipazine has been known as one of the most potent and selective inhibitors of serotonin transporter in vitro and in vivo. Nine derivatives of 6-nitroquipazine were synthesized and tested for their potential abilities to displace [3H]citalopram binding to the rat cortical membranes.

Syntheses and biological evaluation of (18)F-labeled 3-(1-benzyl-piperidin-4-yl)-1-(1-methyl-1H-indol-3-yl)propan-1-ones for in vivo mapping of acetylcholinesterase.

We synthesized novel (18)F-labeled acetylcholinesterase (AChE) inhibitors, 3-[1-(3- and 4-[(18)F]fluoromethylbenzyl)piperidin-4-yl]-1-(1-methyl-1H-i ndol-3-yl )propan-1-ones ([(18)F]1 and [(18)F]2) and 3-[1-(4-[(18)F]fluorobenzyl)piperidin-4-yl]-1-(1-methyl-1H-i ndol-3-yl )propan-1-one ([(18)F]3) in high yields (decay-corrected, 25%-40%) and with high effective specific activities (>37 GBq/micromol). Tissue distribution studies of the [(18)F]1 and the [(18)F]3 in mice showed the nonspecific bindings in brain regions, with metabolic defluorination of the [(18)F]1. The result suggests that these radioligands may not be suitable agents for in vivo mapping of AChE, despite their potent in vitro anti-AChE activities.

Synthesis and biological evaluation of 1-(4-[18F]fluorobenzyl)-4-[(5,6-dimethoxy-1-oxoindan-2-yl)methyl]piperidine for in vivo studies of acetylcholinesterase.

We synthesized and evaluated 1-(4-fluorobenzyl)-4-[(5,6-dimethoxy-1-oxoindan-2-yl)methyl]piperidine (4-FDP), which is an analog of donepezil. The 4-[(18)F]FDP was prepared by reductive alkylation of debenzylated donepezil with 4-[(18)F]fluorobenzaldehyde in high radiochemical yield (decay-corrected, 40-52%) and with high effective specific activity (30-38 GBq/micromol). Tissue distribution studies in mice demonstrated nonspecific distribution of the 4-[(18)F]FDP in brain regions, suggesting that this radioligand may not be a suitable agent for in vivo studies of acetylcholinesterase (AChE), despite its potent in vitro biological activity.

SPECT measurement of iodine-123-beta-CIT binding to dopamine and serotonin transporters in Parkinson's disease: correlation with symptom severity.

Iodine-123-beta-CIT (2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane) binds with high affinity to dopamine (DA) and serotonin (5-HT) transporters. This study examined the correlation of single-photon emission computed tomographic (SPECT) measures of [123I]beta-CIT binding to DA and 5-HT transporters with symptom severity in Parkinson's disease (PD). Forty-six L-dopa-responsive PD patients (Hoehn-Yahr stage 1-3) had SPECT scans at 20-24 h after injection of [123I]beta-CIT. Specific to nondisplaceable uptake ratios (designated V"3) were calculated in the striatum and hypothalamic/midbrain region, where the binding of [123I]beta-CIT is associated primarily with DA and 5-HT transporters, respectively. Striatal V"3 was significantly correlated with Hoehn-Yahr stage and total, motor and activities of daily living scores of Unified Parkinson's Disease Rating Scale (UPDRS). There was a significant correlation between the sum of lateralizing motor UPDRS subscores (tremor, rigidity, bradykinesia) calculated for each side of limbs and V"3 values in the contralateral striatum. No significant correlation was found between striatal V"3 and UPDRS rating of mentation, behavior, and mood. Hypothalamic/midbrain V"3 was not significantly correlated with either Hoehn-Yahr stage or UPDRS scores including both motor and nonmotor measures. The significant correlation of SPECT measures of striatal [123I]beta-CIT binding with motor severity suggests that [123I]beta-CIT binding to striatal DA transporters can serve as an in vivo indicator of disease severity in PD, with potential utility in the serial monitoring of disease progression.

Laparoscopic gastrostomy and jejunostomy: safety and cost with local vs general anesthesia.

BACKGROUND AND HYPOTHESIS: General anesthesia is used for laparoscopic enteral access because pneumoperitoneum requires relaxation of the abdominal muscles. We wanted to determine whether these procedures could be performed with similar results and cost under local anesthesia. DESIGN: Randomized controlled study with 30-day follow-up including a cost-benefit analysis. SETTING: University-affiliated hospitals. PATIENTS: Forty-eight patients (32 men, 16 women; mean age, 67 years) undergoing laparoscopic gastrostomies (n = 32) and jejunostomies (n = 16). INTERVENTION: Twenty-four patients underwent laparoscopic gastrostomy (n = 15) and jejunostomy (n = 9) under local anesthesia with intravenous conscious sedation and monitored anesthesia care. Twenty-four patients had general anesthesia. MAIN OUTCOME MEASURES: Conversion to general anesthesia, complications, and cost. RESULTS: Ten patients under local anesthesia had periods of deep sedation and 1 required conversion to general anesthesia. One patient under general anesthesia required conversion to open gastrostomy. No patients had intraoperative aspiration; however, 4 aspirated after the procedure. One patient died of myocardial infarction during the 30-day follow-up. We found no significant difference in the total mean cost and actual procedure time. The surgeon's fee accounted for 31% of the total cost. CONCLUSIONS: Some patients undergoing laparoscopic enteral access may require deep sedation and a rare patient may require general anesthesia. Clinical conditions and surgeon preference, therefore, should determine whether local anesthesia is suitable for laparoscopic gastrostomies and jejunostomies, and in what setting, since there is no difference in success rate or complications when compared with general anesthesia. Potential savings are possible from the operating room (26% of total cost) or anesthesiologist (12% of total cost) if these procedures are performed in an endoscopy suite without monitored anesthesia care.

[18F]fluoromethylbenzylsulfonate ester: a rapid and efficient synthetic method for the N-[18F]fluoromethylbenzylation of amides and amines.

We have prepared 4-[18F]fluoromethylbenzylsulfonate esters as fluoromethylbenzylating agents. These agents are readily prepared by an [18F]fluoride ion displacement of the corresponding bissulfonate esters. The application of these 4-[18F]fluoromethylbenzylsulfonate esters to N-alkylation reaction of spiperone and 1-phenylpiperazine shows that the products 3-N-(4-[18F]fluoromethylbenzyl)spiperone and 1-N-(4-[18F]fluoromethylbenzyl)-4-phenylpiperazine are rapidly produced with high radiochemical yields under a no-carrier-added condition.

Expression of galectin-1 mRNA in the mouse uterus is under the control of ovarian steroids during blastocyst implantation.

Galectin-1 is a member of beta-galactoside-binding lectins expressed in a variety of mammalian tissues. We report here that galectin-1 mRNA is abundantly expressed in the mouse reproductive organs such as the uterus and ovary. Uterine expression of galectin-1 mRNA is specifically regulated in the embryonic implantation process. Its expression increased at a high level on the fifth day post coitum (dpc 5) when embryos hatched into the endometrial epithelial cells. In the absence of embryos, however, galectin-1 expression in the mouse uterus decreased on dpc 5. In the delayed implantation mice, galectin-1 mRNA levels was augmented by the termination of the delay of implantation. Ovarian steroids progesterone and estrogen differentially regulated galectin-1 mRNA level in uterine tissues. Treatment with RU486, a progesterone receptor antagonist, blocked progesterone-induced galectin-1 mRNA level in uterine tissues of ovariectomized mouse. ICI182780, a pure estrogen receptor antagonist, clearly blocked the estrogen effect. Taken together, galectin-1 gene expression in the uterine tissues was regulated by ovarian steroids and this regulation correlated with the implantation process.

Suppression of GnRH gene expression in GT1-1 hypothalamic neuronal cells: action of protein kinase C.

We attempted to elucidate molecular mechanisms of gonadotropin-releasing hormone (GnRH) gene regulation by the protein kinase C (PKC) pathway in GT1-1 cells. Activation of PKC with 12-tetra-decanoylphorbol-13-acetate (TPA) or inhibition with staurosporine or calphostin C down-regulated GnRH mRNA levels. A serial deletion mutant analysis revealed that this suppression was mediated by the proximal region (-187/-69) of the mouse GnRH promoter. TPA transiently induced c-fos mRNA, whereas staurosporine or calphostin C failed to do so. However, PKC inhibitors blocked the TPA-evoked c-fos induction. Over-expression of PKC alpha down-regulated GnRH promoter activity, indicating that PKC activation was sufficient to inhibit GnRH gene expression. These results suggest that both activation and inhibition of PKC decrease the GnRH gene expression in the GT1-1 cells probably through different signal cascade mechanisms.

Preclinical evaluation of fluorine-18-labeled androgen receptor ligands in baboons.

UNLABELLED: A noninvasive method for detecting and quantifying androgen receptors (AR) in metastatic prostate cancer may be helpful in choosing the method of treatment and in better understanding the pathophysiology of this disease. Nine previously synthesized fluorinated androgens exhibited high affinity binding to AR and showed AR-mediated uptake in the ventral and dorsal prostate of the rat. Further evaluation of these agents for PET imaging is needed since sex hormone binding globulin (SHBG), a glycoprotein which binds androgens with high affinity, is absent in rat blood but is present at high levels in the blood of primates. We chose to study three of the nine fluoro-androgens by PET in the baboon. METHODS: In this study, 16beta-[18F]fluoro-5 alpha-dihydrotestosterone (I), 16beta-[18F]fluoromibolerone (II) and 20-[18F]fluoromibolerone (III) were synthesized and studied in both a young and old male baboon using PET. Blood samples were withdrawn in three of the 10 studies and analyzed for total radioactivity and percent unmetabolized radioligand. Tissue radioactivity was evaluated semiquantitatively, using prostate absolute, standard and target to nontarget uptake values. RESULTS: Prostate uptake was observed with all three 18F-androgens. At 60 min postinjection, compound I gave the highest prostate to soft tissue ratios in both baboons and prostate uptake was shown to be AR-mediated by blocking uptake through the coadministration of testosterone. Compound I gave the highest level of unmetabolized radioligand present in blood up to 45 min postinjection, and gave a 37-fold greater prostate-to-bone ratio at 2 hr postinjection in baboons compared to rats. The favorable behavior of this compound in the baboon may be related to its high affinity for SHBG. CONCLUSION: All three compounds can be used to determine AR-positive tissue in primates. Compound I was selected for the evaluation of AR in men with prostate cancer using PET.

6 alpha-[18F]fluoroprogesterone: synthesis via halofluorination-oxidation, receptor binding and tissue distribution.

We have evaluated 6 alpha-[18F]fluoroprogesterone as a potential imaging agent for progesterone receptor (PgR)-positive breast cancer. 6 alpha-Fluoroprogesterone (1) was obtained via halofluorination of the C-5 double bond in pregnenolone, followed by oxidation of the 3 beta-OH group, elimination of HBr from C-4,5, and epimerization at the C-6 center. The relative binding affinity (RBA) of 6 alpha-fluoroprogesterone (1) to PgR is 11 (R5020 = 100), and its binding selectivity index (BSI, i.e. the ratio of the RBA to the non-specific binding, NSB) is 14.4; these values are similar to those of progesterone. 17 alpha-Acetoxy-6 alpha-fluoroprogesterone (2) was also prepared by the same method, but was not used for fluorine-18 labeling studies because its binding affinity for PgR is very low (0.9). The synthesis of 1 was adapted to fluorine-18 labeling and although the overall radiochemical yield was low (decay-corrected, 0.3%), progestin [18F]1 was obtained in moderately high effective specific activity (147 Ci/mmol). In vivo distribution studies using estrogen-primed immature female rats showed that 6 alpha-fluoroprogesterone ([18F]1) has low uterine uptake, low target tissue selectivity, and high fat uptake, presumably due to its low RBA and BSI. High uptake in bone, which indicates extensive metabolic defluorination, suggests that the C-6 position of steroids may not be a good site for fluorine-18 labeling.

Synthesis of C-6 fluoroandrogens: evaluation of ligands for tumor receptor imaging.

Seven androgens, substituted with fluorine at C-6, were prepared as potential imaging agents for androgen receptor-positive prostate tumors and were evaluated in vitro in terms of their lipophilicity and their relative binding affinities (RBA, relative to R 1881 = 100) for the androgen receptor and for sex steroid binding protein. Introduction of a fluorine atom into the C-6 position of an androgen generally decreases binding affinity to the androgen receptor, except in the two cases: 6 alpha-fluoro-19-nor-testosterone (RBA = 41.6 versus 30.6 for the unsubstituted steroid) and 6 alpha-fluorotestosterone (RBA = 8.9 versus 6.6). Receptor binding of the C-6 fluoro-androgens is also stereospecific, showing higher binding affinities for the alpha-epimers compared to the corresponding beta-epimers (4:1-15:1). Binding affinity to sex steroid binding protein is the lowest with 19-nor-testosterone, which is also the least lipophilic androgen studied. Based on the binding properties of compounds in this series, 6 alpha-fluoro-19-nor-testosterone appears to have the most promise as a tumor imaging agent.

Synthesis of 11 beta-[18F]fluoro-5 alpha-dihydrotestosterone and 11 beta-[18F]fluoro-19-nor-5 alpha-dihydrotestosterone: preparation via halofluorination-reduction, receptor binding, and tissue distribution.

We have prepared 11 beta-fluoro-5 alpha-dihydrotestosterone (11 beta-F-DHT, 1) and 11 beta-fluoro-19-nor-5 alpha-dihydrotestosterone (11 beta-F-19-nor-DHT, 2) in order to investigate the properties of these new androgens labeled with fluorine-18 as potential androgen receptor (AR)-based imaging agents for prostate cancer. These compounds were synthesized in 6 steps from hydrocortisone and in 13 steps from 1,4-androstadiene-3,11,17-trione, respectively. Relative binding affinities (RBA) of 11 beta-F-DHT and 11 beta-F-19-nor-DHT to AR are 53.1 and 75.3 (R1881 = 100), respectively, the latter being the highest reported among fluorine-substituted androgens. The fluorination step, which involves addition of halogen fluoride across the 9(11)-double bond, followed by reductive dehalogenation at the 9 alpha-position has been adapted to introduce a fluorine-18-label at the 11 beta-position of DHT and 19-nor-DHT. The two high-affinity F-18-labeled ligands [18F]-1 and [18F]-2 were evaluated in vivo, in tissue distribution studies using diethylstilbestrol-pretreated mature male rats. 11 beta-F-DHT shows high prostate uptake and selective prostate to blood and prostate to muscle uptake ratios, the latter two ratios increasing from 5 and 8 at 1 h to 12 and 19 at 4 h postinjection. Moreover, this compound has low uptake in bone, displaying the lowest in vivo defluorination among all androgens labeled with fluorine-18 tested so far. The in vivo properties of 11 beta-F-DHT in rats are thus favorable for imaging of prostate cancer. On the other hand, 11 beta-F-19-nor-DHT shows low prostate uptake with low selectivity and high uptake in liver, kidney, and bladder. Even though this ligand has the highest RBA and undergoes little metabolic defluorination, it appears to suffer from rapid metabolism in vivo. Therefore, it is apparent that the biodistribution properties of androgens are affected by their structure and metabolism as well as by their RBA.

Requirement of a second oxidation equivalent for ferryl oxygen transfer to styrene in the epoxidation catalyzed by myoglobin-H2O2.

Ferric myoglobin (Mb) is oxidized by H2O2 to a ferryl (FeIV = O) species and a protein radical, whereas ferrous Mb is similarly oxidized to the ferryl species without the protein radical. The protein radical is unstable and decays within 5 min, but the ferryl species is stable for more than 1 h. Previous studies have shown that styrene is oxidized to styrene oxide and benzaldehyde by ferric Mb and H2O2. We demonstrate here that the ferryl species produced from ferrous equine Mb and H2O2 does not epoxidize styrene. Furthermore, the EPR signal intensity of the protein radical formed from ferric equine Mb and the ability to oxidize styrene decrease in parallel as a function of the time separating the addition of H2O2 and styrene. The ability to oxidize styrene as a function of time after addition of H2O2 is lost much more rapidly with the H64V/K102Q/Y103F/Y146F/Y151F mutant of sperm whale Mb than with the native protein or the Y146F/Y151F mutant. The results indicate that styrene epoxidation requires a two-electron oxidized species of Mb in which the ferryl (FeIV = O) complex is coupled to a protein or highly transient (undetectable) porphyrin radical. Benzaldehyde formation appears to be catalyzed by the same oxidizing species. Styrene oxidation thus differs from linoleic acid oxygenation, which is catalyzed by the ferryl species alone.