C2-Symmetric Chiral Bisoxazolines as Hydrogen-Bond-Acceptor Catalysts in Enantioselective Aldol Reaction of ß-Carbonyl Acids with Trifluoroacetaldehyde Hemiacetals.

A simple C2-symmetric chiral bisoxazoline is demonstrated to use hydrogen bonding to catalyze an important family of aldol reactions of trifluoroacetaldehyde hemiacetals with various ß-carbonyl acids. This reaction is highly enantioselective, delivering chiral nonracemic trifluoromethylated alcohols with excellent optical purity and good isolated yields. This concept of relaying chiral information via a chiral hydrogen-bond acceptor should be applicable to a vast number of organocatalytic processes.

Copper-catalyzed one-pot denitrogenative-dehydrogenative-decarboxylative coupling of ß-ketoacids with trifluorodiazoethane: facile access to trifluoromethylated aldol products.

A novel copper-catalyzed one-pot cross-coupling of ß-ketoacids with in situ generated trifluorodiazoethane has been developed. This reaction provides a direct and efficient method, in which one C-C bond and one C-O bond were formed in a carbenoid center with concomitant denitrogenation-dehydrogenation-decarboxylation, to afford trifluoromethylated aldol products. In several preliminary experiments, good to high enantioselectivities were also obtained.

[Preliminary result of dynamic contrast-enhanced MR imaging in assessment of cellularity characteristics of bone marrow in patients with haematological malignancies].

OBJECTIVE: To evaluate the correlation of bone marrow status in haemotological malignancy patient with the variable value of dynamic contrast-enhanced MR (DCE-MRI). METHODS: DCE-MRI result were obtained from 25 patients with pathologically proven haematological malignancies. Time-signal intensity curves (TIC) was generated from the region of the iliac crest corresponding to the planned biopsy site. Enhancement characteristics including peak enhance ratio (PER) , maximum slope (Slopemax), time to peak ( TP) and mean time (MT) were analyzed. The patients received bone marrow biopsy on the crest 30 min after DCE-MRI, and then the parameters of bone marrow histology including cellularity was analyzed. RESULTS: In this series, 3 patients showed type B TIC, 7 type C, 13 type D and 2 type E. The bone marrow cellularity with haematological malignancies cannot be demostrated by TIC type. The mean PER value and Slopemax value in the patients with hypercellularity was significantly higher than that with normal cellularity and hypocellularity. The mean TTP value of the patients with hypercellularity (60.20 +/- 61.62) was significantly lower than that in the patients with hypocellularity (97.43 +/- 1.07) or normal cellularity (78.44 +/- 38.02). There was no significant difference in the mean MT value among three groups. CONCLUSION: Our preliminary findings suggest that the bone marrow cellularity in the patient with haematological malignancies can not be revealed by conventional MR, but it may be demonstrated by semi-quantitative calculation of the variable value from DCE-MR imaging.

Tumor infiltration of bone marrow in patients with hemato-logical malignancies: dynamic contrast-enhanced magnetic resonance imaging.

BACKGROUND: Conventional magnetic resonance (MR) scanning techniques can identify bone marrow (BM) containing mostly fat cells. But they are not able to differentiate BM tumor infiltration, BM fibrosis and normal red BM. This is particularly problematic in assessment of recurrent or refractory hematological malignancy. This pilot study used dynamic contrast-enhanced MR imaging (DCE-MRI) to evaluate the bone marrow status and to determine whether several calculated parameters derived from the DCE-MRI correlate with histological characteristics of marrow, especially with the tumor fraction (TF). METHODS: DCE-MRI scans were performed in 25 patients with proven or known hematological malignancy who were about to undergo bone marrow biopsy of the posterior iliac crest. The location chosen for biopsy was examined with MRI approximately one hour prior to the biopsy. Time-signal intensity curves (TIC) were generated from the region of the iliac crest corresponding to the planned biopsy site. Enhancement parameters were calculated, including peak enhancement ratio (PER), maximum enhancement slope (Slope(max)), time to peak (TTP) and mean time (MT). The biopsy specimen was reported synoptically, with relevant reported parameters including cellularity and tumor fraction (TF). RESULTS: PER values were significantly higher for the bone marrow tumor infiltration group than for the normal bone marrow group (P < 0.05). A significant positive correlation was found between PER and TF as well as Slope(max) and TF. A negative correlation was found between TTP and TF. There was no significant difference in the mean TTP and MT values between the BM tumor infiltration group and the normal bone marrow group. CONCLUSIONS: The presence of diffuse bone marrow infiltration in patients with haematological malignancies could be verified using DCE-MRI.

[Prefrontal and superior temporal lobe hyperactivity as a biological substrate of generalized anxiety disorders].

OBJECTIVE: To explore the potential mechanism of generalized anxiety disorders (GAD). METHODS: Ten GAD patients and 10 sex- and age-matched healthy persons underwent functional magnetic resonance imaging (fMRI) study in 2 stages by block design: auditory presentation of the stimulation task. In experiment 1 emotionally neutral words were given and then alternated with a no word period for 8 cycles. In experiment 2 emotionally neutral words and threat-related words were given alternately for 8 cycles. The subjects were asked to listen carefully and then judge their subjective feeling in mind. By the end of experiment they were asked to fill in a state anxiety inventory (STAI-S) so as to calculate the STAI-S scores. RESULTS: The mean STI-S score of the patients in the experiment 1 was 57 +/- 5, significantly higher than that of the healthy persons (37 +/- 3, P < 0.01); and the mean STAI-S score in the experiment 2 of the patients was 66 +/- 6, significantly higher than that of the healthy persons (41 +/- 4, P < 0.01). The fMRI findings showed that in the experiment 1 the activated cerebral regions of the 2 groups were mostly overlapped, including bilateral superior temporal gyri (BA22/42) and middle temporal gyri (BA21), premotor areas (B46), and supplementary motor areas (BA6), and cerebellar hemisphere, and left inferior prefrontal gyrus (BA44/45). However, the activation intensity levels (mean T values) of the bilateral superior temporal gyri of the patients were both significantly higher than those of the control (for the left side: P = 0.051, and for the right side: P = 0.035). In addition, activation of the dorsal lateral prefrontal cortex (BA8/9) and bilateral inferior parietal lobules (BA39/40). In the experiment 2 activation of brain areas could be seen only in the patients, including bilateral superior temporal gyri, middle temporal gyri, inferior prefrontal gyri, inferior parietal lobules, anterior motor areas, supplemental motor areas, and anterior cingulate gyri (BA8/24/32), and left dorsal lateral prefrontal cortex. No significantly activated brain area could be shown in the control at the same stringent statistic level (P < 0.01, uncorrected); however, when the threshold value (P value) was reduced to 0.01, the left anterior cingulate gyrus (BA24/32), posterior cingulate gyrus (BA29/30), and inferior parietal lobules (BA40) were all significantly activated. CONCLUSION: Dysfunction of superior temporal lobe and dorsal prefrontal cortex, characterized by hyperactivity in response to outer stimuli, may play an important role in the psychopathologic mechanism of GAD.

[Heterogeneity of aging brain: a preliminary comparative study of functional magnetic resonance imaging in elderly people].

OBJECTIVE: To explore the heterogeneity of aging brain. METHODS: Blood oxygenation level dependent functional magnetic resonance imaging was performed on 10 subjects meeting the standards of successful aging (SA), 9 subjects meeting the standards of usual aging (UA), and 9 subjects meeting the criteria of mild cognitive impairment (MCI), all age, and sex-matched, under stimulation of verbal fluent test (VFT). The activation level of different regions of interest (ROI), laterality index, and the activation level of occipital lobe were analyzed. RESULTS: The achievement in VFT of the SA group was greater than that of the UA group, and much greater than that of the MCI group with significant differences between any 2 groups (all P < 0.05) except in the task of "names of vegetables". The activation volume of the SA group was greater than that of the UA group, and much greater than that of the MCI group. The main activated regions of the SA and UA groups included left precuneus, anterior cingulate gyrus, middle frontal gyrus, superior frontal gyrus and inferior parietal lobule, and bilateral occipital lobes. The main activated regions of the MCI group included the bilateral prefrontal lobe. The intensity of activation was not significantly different between the SA and UA groups, however, was significantly different between the SA and MCI groups and between the UA and MCI groups. The laterality index (LI) was 0.46 in the SA group, significantly higher than those of the UA group (-0.12) and MCI group (-0.06) (both P < 0.01), however, without a significant difference between the UA group and MCI group. The activation of left prefrontal lobe in the SA group was more obvious than that in the UA group, and much more obvious than that in the MCI group with a significant difference between the UA and MCI groups as well (all P < 0.01). The activation volume of the left dorsal lateral prefrontal cortex (DLPFC) in the SA group was 787 voxels, significantly greater than that in the UA group (292 voxels) and MCI group (0 voxel) (all P < 0.01). CONCLUSION: Heterogeneity exists in the course of aging, associated with complicated brain mechanism. The activation level of DLPFC and LI may be used as sensitive indexes in evaluation of the brain function of the elderly.