Dual inversion recovery ultrashort echo time (DIR-UTE) imaging and quantification of the zone of calcified cartilage (ZCC)

OBJECTIVE

To develop ultrashort echo time (UTE) magnetic resonance imaging (MRI) techniques to image the zone of calcified cartilage (ZCC), and quantify its T2*, T1 and T1ρ.

DESIGN

In this feasibility study a dual inversion recovery UTE (DIR-UTE) sequence was developed for high contrast imaging of the ZCC. T2* of the ZCC was measured with DIR-UTE acquisitions at progressively increasing TEs. T1 of the ZCC was measured with saturation recovery UTE acquisitions at progressively increasing saturation recovery times. T1ρ of the ZCC was measured with spin-locking prepared DIR-UTE acquisitions at progressively increasing spin-locking times.

RESULTS

The feasibility of the qualitative and quantitative DIR-UTE techniques was demonstrated on phantoms and in six cadaveric patellae using a clinical 3 T scanner. On average the ZCC has a short T2* ranging from 1.0 to 3.3 ms (mean ± standard deviation = 2.0 ± 1.2 ms), a short T1 ranging from 256 to 389 ms (mean ± standard deviation = 305 ± 45 ms), and a short T1ρ ranging from 2.2 to 4.6 ms (mean ± standard deviation = 3.6 ± 1.2 ms).

CONCLUSION

UTE MR based techniques have been developed for high resolution imaging of the ZCC and quantitative evaluation of its T2*, T1 and T1ρ relaxation times, providing non-invasive assessment of collagen orientation and proteoglycan content at the ZCC and the bone cartilage interface. These measurements may be useful for non-invasive assessment of the ZCC, including understanding the involvement of this tissue component in osteoarthritis.

Mitochondrial bioenergetic deficits in the hippocampi of rats with chronic ischemia-induced vascular dementia

Vascular dementia (VD), defined as a loss of memory and cognitive function resulting from vascular lesions in the brain, is the second-most-common cause of dementia in the elderly, after Alzheimer's disease. In recent years, research has focused on the pathogenesis of VD, and mitochondrial bioenergetic deficits have been suggested to contribute to VD onset. To further investigate the role of mitochondria in VD, we used a rat model of VD, which involved permanent bilateral occlusion of the common carotid arteries (with a 1-week interval between artery occlusion to avoid an abrupt reduction in cerebral blood flow) leading to chronic cerebral hypoperfusion. Prior to occlusion, male Wistar rats underwent 7 days of Morris water maze training. Only animals that could swim and passed the Morris water maze test were chosen for the study. After 5 days of Morris water maze training, mitochondria from the hippocampi of rats, which were randomly selected from animals that could complete the Morris water maze test, were isolated for functional assessment. Mitochondria isolated from the hippocampi of rats from the ischemia group had decreased pyruvate dehydrogenase protein levels, and increased oxidative stress, as manifested by increased hydrogen peroxide production. The ischemia group mitochondria also exhibited decreased respiration coupled to decreased expression and activity of the electron transport chain complex IV (cytochrome c oxidase). These results indicate that the mitochondrial oxidative metabolism is inhibited in the hippocampi of rats following chronic ischemia-induced VD. As the mitochondrial oxidative metabolism deficits, namely mitochondrial bioenergetic deficits directly affect the functions of neurons, it may contribute to VD onset.

Magnetic properties of (Fe50Co50)(1-x)-Gdx thin films with diluted Gd doping

(Fe50Co50)(1-x)-Gdx thin films (30 nm) with x<15% deposited on silicon substrates by magnetron sputtering were investigated by X-ray diffraction, vibrating sample magnetometer, and ferromagnetic resonance. Theoretical fittings of the angular dependent ferromagnetic resonance field of the FeCoGd films have been performed using the Landau-Lifshitz equation It is found that the ferromagnetic resonance experimental data is well fitted by the theory and various magnetic properties have been extracted in accordance. The saturation magnetization decreases from 22750 Oe at x = 0% to 14079 Oe at x = 14% in the FeCo-Gd film, and the perpendicular magnetic anisotropy has changed from an easy film plane to an easy film normal geometry. The gyromagnetic ratio, as well as the Landé g factor, are found increased also with increasing Gd content, i.e. from g = 2.08 at x = 0% to g = 2.29 at x = 14%. An enhancement of the L-S coupling in the presence of a low Gd content has been concluded based on an observable increase from 0.011 at x = 12% up to 0.015 at x = 14% in the Gilbert damping.

Enzymatic synthesis oF L-tryptophan from D,L-2-amino-delta2-thiazoline-4-carboxylic acid and indole by Pseudomonas sp. TS1138 L-2-amino-delta2-thiazoline-4-carboxylic acid hydrolase, S-carbamyl-L-cysteine amidohydrolase, and Escherichia coli L-tryptophanase

L-Tryptophan (L-Trp) is an essential amino acid. It is widely used in medical, health and food products, so a low-cost supply is needed. There are 4 methods for L-Trp production: chemical synthesis, extraction, enzymatic synthesis, and fermentation. In this study, we produced a recombinant bacterial strain pET-tnaA of Escherichia coli which has the L-tryptophanase gene. Using the pET-tnaA E. coli and the strain TS1138 of Pseudomonas sp., a one-pot enzymatic synthesis of L-Trp was developed. Pseudomonas sp. TS1138 was added to a solution of D,L-2-amino-delta2-thiazoline-4-carboxylic acid (DL-ATC) to convert it to L-cysteine (L-Cys). After concentration, E. coli BL21 (DE 3) cells including plasmid pET-tnaA, indole, and pyridoxal 5'-phosphate were added. At the optimum conditions, the conversion rates of DL-ATC and L-Cys were 95.4% and 92.1%, respectively. After purifying using macroporous resin S8 and NKA-II, 10.32 g of L-Trp of 98.3% purity was obtained. This study established methods for one-pot enzymatic synthesis and separation of L-Trp. This method of producing L-Trp is more environmentally sound than methods using chemical synthesis, and it lays the foundations for industrial production of L-Trp from DL-ATC and indole.

Derivation of severity index for rheumatoid arthritis and its association with healthcare outcomes

OBJECTIVES

To develop a claims-based severity index for rheumatoid arthritis (RA) using the Veterans Health Administration (VHA) database.

METHODS

Adult patients with at least two RA diagnoses 2 months apart were identified between 10/1/2008-09/30/2009. Patients were required to have at least 12 months continuous health plan enrollment before and after the index date (first RA diagnosis date) for an overall study period of 10/1/2007-09/30/2010. A severity index for rheumatoid arthritis (SIFRA, a proprietary algorithm of SIMR, Inc. [STATinMED Research]) was developed by calculating a weighted sum of 34 RA-related indicators assessed by an expert Delphi panel of six rheumatologists, including laboratory, clinical, and functional status, extra-articular manifestations, surgical history, and medications, during a 1-year pre-index period. Separate SIFRA versions were derived for patients with and without laboratory information. Correlations between SIFRA and previously validated claims-based indexes for RA severity (CIRAS), and other traditional comorbidity indexes were calculated during the pre-index period. The relationship between SIFRA and follow-up healthcare outcomes was also examined using histograms.

RESULTS

The Spearman's rank correlations between SIFRA and CIRAS were 0.525 for SIFRA without and 0.539 with laboratory data. The correlations between SIFRA and the Charlson Comorbidity Index (CCI) (0.1503 without, 0.1135 with laboratory data), Elixhauser Index (ELIX) (0.105 without, 0.079 with laboratory data), and Chronic Disease Score (CDS) (0.255 without, 0.239 with laboratory data) were low. Histograms showed that patients in the upper tercile of SIFRA incurred $9123 more all-cause and $1326 more RA-related healthcare costs during the 1-year post-index period than patients in the lower tercile. Using SIFRA in combination with CCI, CDS, or ELIX significantly increased the percentage of variation explained in outcomes measures.

LIMITATIONS

Patients in the VHA database may not represent typical RA patients since the database generally contains older, economically disadvantaged men with a high disease burden. Validity of the score is indirectly based on disease activity score 28 (DAS28), which measures disease activity rather than severity.

CONCLUSIONS

SIFRA was found to have moderate correlations with the previously validated CIRAS score, and demonstrated evidence of being a significant determinant of total and RA-related healthcare costs for RA patients. This study suggests that SIFRA could be an important methodological tool to control for severity in RA-related outcomes research. The algorithm can be applied to any claims dataset.

Systematic review of intraoperative cholangiography in cholecystectomy

BACKGROUND

Intraoperative cholangiography (IOC) is used to detect choledocholithiasis and identify or prevent bile duct injury. The aim of this study was systematically to review the randomized clinical trials of IOC for these two indications.

METHODS

MEDLINE, Embase, the Cochrane Library, clinicaltrials.gov and the World Health Organization database of clinical trials were searched systematically (January 1980 to February 2011) to identify trials. Two authors performed the literature search and extracted data independently. Primary endpoints were bile duct injury and retained common bile duct (CBD) stones diagnosed at any stage after surgery. Preliminary meta-analysis was undertaken, but the trials were too methodologically heterogeneous and the outcome events too infrequent to allow meaningful meta-analysis.

RESULTS

Eight randomized trials were identified including 1715 patients. Six trials assessed the value of routine IOC in patients at low risk of choledocholithiasis. Two trials randomized all patients (including those at high risk) to routine or selective IOC. Two cases of major bile duct injury were reported, and 13 of retained CBD stones. No trial demonstrated a benefit in detecting CBD stones. IOC added a mean of 16 min to the total operating time.

CONCLUSION

There is no robust evidence to support or abandon the use of IOC to prevent retained CBD stones or bile duct injury. Level 1 evidence for IOC is of poor to moderate quality. None of the trials, alone or in combination, was sufficiently powered to demonstrate a benefit of IOC. Further small trials cannot be recommended.

Hepatitis C among methadone maintenance treatment patients in Shanghai and Kunming, China

BACKGROUND

This study aims to: (1) document the prevalence of hepatitis C virus (HCV) among methadone maintenance treatment (MMT) patients in Kunming and Shanghai; (2) examine risk factors for HCV by comparing those who tested positive with those who were negative and (3) examine if HCV serostatus is related to attitudes toward MMT.

METHODS

Using data collected from 306 patients admitted to MMT in 2009-2010 in Shanghai and Kunming, we compared HCV-positive and HCV-negative patients (based on clinical records) on their HCV knowledge and risk behaviors and attitudes toward MMT.

RESULTS

The HCV seropositive rate was 53.3% (51.3% in Shanghai and 55.5% in Kunming) and a majority of patients did not know their serostatus. Patients scored on average fewer than 6 correct out of the 20 items in the HCV knowledge questionnaire. Recent injection use and length of opiate use were strong predictors of HCV status, while no differences were found between HCV-positive and HCV-negative individuals in sexual risks or HCV knowledge. Both groups expressed similar views toward MMT.

CONCLUSION

The high HCV prevalence and the general lack of knowledge about HCV infection, transmission and treatment suggest the need to provide HCV education and health promotion programs among patients in MMT.

Expression of smoothened in mouse embryonic maxillofacial development

Hedgehog (Hh) signaling plays many key roles in the development of Drosophila and vertebrate embryos including regulation of craniofacial development. The seven-transmembrane protein, smoothened (Smo) transduces the Hh signal across the plasma membrane as an essential receptor of PTCHED1/2. There are few studies that evaluate the detailed expression of Smo in mouse embryonic craniofacial development. We investigated the expression patterns of Smo during murine embryonic craniofacial development using in situ hybridization (ISH), studies of whole-mounts and sections, immunohistochemistry, quantitative real time PCR, and Western blot analysis. We found that Smo mRNA was expressed in the face of mouse embryos at 11 and 12.5 days post coitum (dpc). After 13.5 dpc, the expression decreased to a low level and was faintly detected after birth. Smo protein could be detected also in embryos at 11, 12.5, and 14.5 dpc. After 15.5 dpc, the expression was very faint and paralleled the gene expression studies. No expression was detected in whisker follicle during facial development and faint signal was detected in Meckel's cartilage. These findings concerning Smo expression should guide further investigation of sonic Hh signaling pathway gene function during maxillofacial development.

Concentration-dependent mobility, retardation, and speciation of iodine in surface sediment from the Savannah River Site

Iodine occurs in multiple oxidation states in aquatic systems in the form of organic and inorganic species. This feature leads to complex biogeochemical cycling of stable iodine and its long-lived isotope, (129)I. In this study, we investigated the sorption, transport, and interconversion of iodine species by comparing their mobility in groundwaters at ambient concentrations of iodine species (10(-8) to 10(-7) M) to those at artificially elevated concentrations (78.7 μM), which often are used in laboratory analyses. Results demonstrate that the mobility of iodine species greatly depends on, in addition to the type of species, the iodine concentration used, presumably limited by the number of surface organic carbon binding sites to form covalent bonds. At ambient concentrations, iodide and iodate were significantly retarded (K(d) values as high as 49 mL g(-1)), whereas at concentrations of 78.7 μM, iodide traveled along with the water without retardation. Appreciable amounts of iodide during transport were retained in soils due to iodination of organic carbon, specifically retained by aromatic carbon. At high input concentration of iodate (78.7 μM), iodate was found to be reduced to iodide and subsequently followed the transport behavior of iodide. These experiments underscore the importance of studying iodine geochemistry at ambient concentrations and demonstrate the dynamic nature of their speciation during transport conditions.