Test‐retest reliability and reproducibility of short‐echo‐time spectroscopic imaging of human brain at 3T

A ¹H magnetic resonance spectroscopic imaging study at 3T and short echo time was conducted to evaluate both the reproducibility, as measured by the interscan coefficient of variation (CV), and test‐retest reliability, as measured by the intraclass correlation coefficient (ICC), of measurements of glutamate (Glu), combined glutamate and glutamine (Glx), myo‐inositol (mI), N‐acetylaspartate, creatine, and choline in 21 healthy subjects. The effect of partial volume correction on these measures and the relationship of reproducibility and reliability to data quality were also examined. A ¹H magnetic resonance spectroscopic imaging slice was prescribed above the lateral ventricles and single repeat scans were performed within 30 min to minimize physiologic variability. Interscan CVs based on all the voxels varied from 0.05 to 0.07 for N‐acetylaspartate, creatine, and choline to 0.10–0.13 for mI, Glu, and Glx. Findings on the reproducibility of gray and white matter estimates of N‐acetylaspartate, creatine, and choline are consistent with previous studies using longer echo times, with CVs in the range of 0.02–0.04 and ICC in the range of 0.65–0.90. CVs for Glu, Glx, and mI are much lower than reported in previous studies at 1.5T, while white matter mI (CV = 0.04, ICC = 0.93) and gray matter Glx (CV = 0.04, ICC = 0.68) demonstrated both high reproducibility and test‐retest reliability. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

Understanding of the mass spectrometric fragmentation pathways of a few potentially genotoxic haloaniline isomers in their protonated form by collision-induced dissociation

Collision-induced dissociation (CID) mass spectra of a few haloaniline isomers, (chloroanilines, dichloroanilines, difluoroanilines, chloro-fluoroanilines and bromo-fluoroanilines) were characterized. The mass spectral behaviour of difluoroanilines was different from those of the corresponding regioisomers of the other haloanilines. For all ortho regioisomers except difluoroanilines, CID mass spectra resulted in hydrogen halide as well as halogen radical loss. In the case of difluoroanilines, peaks corresponding to hydrogen fluoride loss were observed during the same process. Meta and para-haloanilines have the tendency to lose either ammonia or halogen radicals. Six regioisomers of dichloroanilines were subjected to hydrogen/deuterium exchange experiments in solution to determine the CID fragmentation pathways. From the experimental results we propose two fragmentation pathways for the dicholoroanilines: (a) formation of aza-biheterocyclic intermediate and (b) via heterolytic hydrogen transfer from the charged center. The demonstrated unique characteristics in CID mass fragmentation of haloanilines may be useful in identification and differentiation of isomers as impurities during chemical process development. A good use of the ortho effect is the significant differentiation between 2-chloro-4-fluoroaniline and 4-chloro-2-fluoroaniline by CID mass spectra.     

Identification of an unintended consequence of Nrf2-directed cytoprotection against a key tobacco carcinogen plus a counteracting chemopreventive intervention

NF-E2-related factor 2 (Nrf2) is a major cytoprotective gene and is a key chemopreventive target against cancer and other diseases. Here we show that Nrf2 faces a dilemma in defense against 4-aminobiphenyl (ABP), a major human bladder carcinogen from tobacco smoke and other environmental sources. Although Nrf2 protected mouse liver against ABP (which is metabolically activated in liver), the bladder level of N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-ABP), the predominant ABP-DNA adduct formed in bladder cells and tissues, was markedly higher in Nrf2(+/+) mice than in Nrf2(-/-) mice after ABP exposure. Notably, Nrf2 protected bladder cells against ABP in vitro. Mechanistic investigations showed that the dichotomous effects of Nrf2 could be explained at least partly by upregulation of UDP-glucuronosyltransferase (UGT). Nrf2 promoted conjugation of ABP with glucuronic acid in the liver, increasing urinary excretion of the conjugate. Although glucuronidation of ABP and its metabolites is a detoxification process, these conjugates, which are excreted in urine, are known to be unstable in acidic urine, leading to delivery of the parent compounds to bladder. Hence, although higher liver UGT activity may protect the liver against ABP, it increases bladder exposure to ABP. These findings raise concerns of potential bladder toxicity when Nrf2-activating chemopreventive agents are used in humans exposed to ABP, especially in smokers. We further show that 5,6-dihydrocyclopenta[c][1,2]-dithiole-3(4H)-thione (CPDT) significantly inhibits dG-C8-ABP formation in bladder cells and tissues but does not seem to significantly modulate ABP-catalyzing UGT in liver. Thus, CPDT exemplifies a counteracting solution to the dilemma posed by Nrf2.     

Establishment and characterization of a new highly metastatic human osteosarcoma cell line

Osteosarcoma is the most common primary malignancy of bone in children and young adults. There is a paucity of tumorigenic and highly metastatic human osteosarcoma cell lines that have not been further transformed by exogenous means. Here we establish and characterize a highly metastatic human osteosarcoma cell line that is derived from a poorly metastatic MG63 line through serial passage in nude mice via intratibial injections. The occasional pulmonary metastases developed from MG63 were harvested and repassaged in mice until a highly metastatic subline (MG63.2) was established. The parental MG63 and highly metastatic MG63.2 cells were further characterized in vitro and in vivo. MG63.2 cells demonstrated increased cell migration and invasion compared to the parental MG63 cells. Conversely, cell adhesion was significantly greater in MG63 cells when compared to the MG63.2 cells. MG63.2 cells grew at a slightly slower rate than that of the parental cells. When injected into nude mice, MG63.2 cells had a greater than 200-fold increase in developing pulmonary metastases compared to the parental MG63 cells. MG63.2 cells also formed larger primary tumors when compared to the parental MG63 cells. Further analysis revealed that ezrin expression was up-regulated in the metastatic MG63.2 cells. Interestingly, expressions of MMP-2 and MMP-9 were down-regulated, and expression of TIMP-2 was up-regulated in the MG63.2 cells. Taken together, we have established and characterized a highly metastatic human osteosarcoma cell line that should serve as a valuable tool for future investigations on the pathogenesis, metastasis, and potential treatments of human osteosarcoma.     

Attitude Mismatching: Discrepancies in the Sexual Attitudes of African American Mothers and their Pre-adolescent Children

The present study examined attitude congruence between mothers and their pre-adolescent children regarding the precursors of sexual behavior (i.e., having a boyfriend/girlfriend, dating), timing of sexual initiation (i.e., waiting until marriage to have sex), and the potential consequences of sexual behavior (i.e., the seriousness of pregnancy and AIDS). A sample of 932 fourth and fifth grade African American children and their mothers participated by completing computer-administered surveys. The results indicated significant discrepancies between maternal and child attitudes, particularly regarding the precursors of sexual behavior. In addition, children often inaccurately perceived their mothers’ attitudes, and evidence suggested that lack of sexual communication is associated with some of these misperceptions. The implications of sexual attitude discrepancies between mothers and children for prevention programs are discussed.     

Development of l-CDB-4022 as a nonsteroidal male oral contraceptive: induction and recovery from severe oligospermia in the adult male cynomolgus monkey (Macaca fascicularis)

The present study was undertaken to examine the antispermatogenic effect of l-CDB-4022 in the adult male cynomolgus monkey. Monkeys (four per group) were dosed via nasogastric tube for 7 d with l-CDB-4022 at 12.5 mg/kg.d or vehicle (d 0=first day of dosing). Plasma levels of l-CDB-4022 and its deesterified metabolite were nondetectable prior to treatment and in all vehicle-treated monkeys. Peak levels of l-CDB-4022 and its metabolite were observed at 4 h after dosing with steady-state levels apparent around d 4. Sperm concentration and total sperm per ejaculate were decreased to levels below 1x10(6) sperm/ml or sperm/ejaculate in l-CDB-4022-treated monkeys by d 17 and remained suppressed through wk 6. Sperm motility also declined to 0% for 6 wk. Testicular volume was reduced in l-CDB-4022-treated monkeys through d 21. The left testis and epididymis were removed from all monkeys on d 24. At this time, the most mature germ cells in the seminiferous tubules of testes from l-CDB-4022-treated monkeys were either spermatocytes or round spermatids. Immature germ cells, but not mature sperm, were found in the efferent ducts and collapsed epididymal lumen of l-CDB-4022-treated monkeys. A steady recovery in sperm motility, concentration, and total sperm per ejaculate was observed in l-CDB-4022-treated monkeys such that these parameters were not different from those of vehicle-treated monkeys by wk 16. Volume of the remaining testis increased in vehicle- and l-CDB-4022-treated monkeys after hemicastration; however, the increase in l-CDB-4022-treated monkeys was delayed compared with that observed in the vehicle-treated monkeys. The morphology of the remaining testis and epididymis, which were removed on wk 17, was normal. Serum inhibin B levels were increased in l-CDB-4022-treated monkeys during the dosing interval; thereafter serum inhibin B levels declined such that there was no difference between the groups by wk 3. l-CDB-4022 treatment did not affect circulating levels of testosterone, LH, FSH, or estradiol. In conclusion, these data indicate that in the cynomolgus monkey, a representative higher primate, l-CDB-4022 exerts a selective antispermatogenic action, which was reversible under the conditions of this study and thus has potential as a nonhormonal oral male contraceptive.     

Primary and revision lumbar discectomy: A three-year review from one center

Background:

Despite variations in technique, the results of primary and revision lumbar discectomy have been good. The aim of this study was to retrospectively review cases of primary and revision lumbar discectomy performed in our institute over a three-year period.

Materials and Methods:

The case records of 273 patients who underwent lumbar discectomy between January 2001-2004 and fulfilled our inclusion and exclusion criteria were reviewed. Of these, 259 were primary discectomies and 14 were revision surgeries. Recurrence was defined as ipsilateral disc herniation at the previously operated level. Demographic parameters, magnetic resonance imaging of the disc, patient satisfaction and rate of recurrence were analyzed.

Results:

The primary surgery group had 52 (20.08%) contained and 207 (79.92%) extruded or sequestered discs, while the numbers in the revision group were three (21.43%) and 11 (78.57%) respectively. “Satisfactory” outcome was noted in 96.5% of the primary surgeries, with a recurrence rate of 3.5%. In the revision group 78.6% had “satisfactory” outcome. In 9.4% of the primary group we encountered complications, while it was 21.43% in the revision group.

Conclusions:

Lumbar discectomy is a safe, simple and effective procedure with satisfactory outcome in 96.5% of primary disc surgery and 78.6% of revision disc surgery.