Rapid measurement of three-dimensional diffusion tensor

In this article, the authors demonstrate a rapid NMR method to measure a full three-dimensional diffusion tensor. This method is based on a multiple modulation multiple echo sequence and utilizes static and pulsed magnetic field gradients to measure diffusion along multiple directions simultaneously. The pulse sequence was optimized using a well-known linear inversion metric (condition number) and successfully tested on both isotropic (water) and anisotropic (asparagus) diffusion systems.

NAD+-linked 15-hydroxyprostaglandin dehydrogenase: structure and biological functions

NAD(+)-linked 15-hydroxyprostaglandin dehydrogenase (15-PGDH) catalyzes the oxidation of 15(S)-hydroxyl group of prostaglandins and lipoxins resulting in the formation of 15-keto metabolites which exhibit greatly reduced biological activities. Therefore, this enzyme has been considered the key enzyme responsible for the inactivation of prostaglandins and lipoxins. Both the cDNA and the genomic DNA of the 15-PGDH gene have been cloned. Structural characterization, transcriptional regulation and biological functions of this enzyme have been investigated. Molecular modeling corroborated with site-directed mutagenesis has identified key residues and domains involved in coenzyme and substrate binding. Catalytic mechanism has been proposed. Studies on the regulation of enzyme expression and activity by physiological and pharmacological agents have begun to uncover its significant roles in cancer, inflammation and reproduction. Apparently, 15-PGDH works with cyclooxygenase-2 to control the cellular levels of prostaglandins. Their reciprocal regulation within the same cells appears to determine the fate of the cells. Because of its ability to inactivate both prostaglandins and lipoxins of two opposite biological activities, the roles of 15-PGDH in cancer and inflammation are particularly intriguing and challenging. Future investigations in these areas are warranted.

Titin-cap (TCAP) polymorphisms associated with marbling score of beef

Marbling score (MS) is the major qualitative trait that affects carcass quality in beef cattle. In this study, we examined the association between genetic polymorphisms of the titin-cap gene (TCAP) and carcass traits in Korean native cattle (also known as Hanwoo). By direct DNA sequencing in 24 unrelated Korean cattle, we identified five sequence variants in 1.2kb of TCAP. Among them, four common polymorphic sites were selected for genotyping in the beef cattle (n=437). Pair-wise linkage analysis with four polymorphisms showed strong linkage disequilibrium (LD), and three major haplotypes (freq.>0.1) were constructed. Statistical analysis revealed that polymorphisms in intron1 (g.346G>A) and exon2 (g.592-597CTGCAG[Leu-Gln]insdel) showed significant association with marbling score (P(cor.)=0.003 and 0.02, respectively). One haplotype, ht2[C-G-G-del], also showed significant association with MS (P(cor.)=0.0004). Our findings suggest that polymorphisms in TCAP might be among the important genetic factors involved in carcass quality in beef cattle.

The persistence of humoral and cellular immunities more than three decades after smallpox vaccination

This study assessed the persistence of humoral (neutralising antibody titre to vaccinia virus) and cellular (immediate vaccinia-specific interferon (IFN)-gamma-producing T-cell) immunities to smallpox in a Korean population. Individuals who were vaccinated 25-60 years previously had higher neutralising antibody titres (geometric mean titre (GMT) 13.7; 95% CI 11.0-17.2) than vaccinia-naive individuals (GMT 6.7; 95% CI 5.5-8.0; p <0.001). However, there was no significant difference in cellular immunity between individuals vaccinated previously and vaccinia-naive individuals, and only 15% of the individuals vaccinated previously displayed an immediate IFN-gamma-producing effector-memory response in ELISPOT assays.

Cross sections and oscillator strengths for electron-impact excitation of the ÃB11 electronic state of water

The authors report absolute differential and integral cross section measurements for electron-impact excitation of the A (1)B(1) electronic state of water. This is an important channel for the production of the OH (X (2)Pi) radical, as well as for understanding the origin of the atmospheric Meinel [Astrophys. J. 111, 555 (1950)] bands. The incident energy range of our measurements is 20-200 eV, while the angular range of the differential cross section data is 3.5 degrees -90 degrees . This is the first time such data are reported in the literature and, where possible, comparison to existing theoretical work, and new scaled Born cross sections calculated as a part of the current study, is made. The scaled Born cross sections are in good agreement with the integral cross sections deduced from the experimental differential cross sections. In addition they report (experimental) generalized oscillator strength data at the incident energies of 100 and 200 eV. These data are used to derive a value for the optical oscillator strength which is found to be in excellent agreement with that from an earlier dipole (e,e) experiment and an earlier photoabsorption experiment.

Fidelity of implementation in a treatment effectiveness trial of Reconnecting Youth

In 'a treatment effectiveness trial', a program is evaluated in a real-world setting, with an emphasis on achieving high implementation fidelity. Through fidelity assessment, the link between program implementation and outcomes is systematically evaluated and ultimately leads to a greater understanding of program success or failure. This paper reports the results of an implementation fidelity study of the 'Reconnecting Youth' (RY) prevention program. The research questions were (i) was the program implemented with fidelity? and (ii) did better fidelity predict better outcomes? RY is an indicated drug abuse prevention program for high school students that seeks to 'reconnect' high-risk youth to school before they drop out. The results reported here were part of a randomized controlled effectiveness trial of the RY prevention program conducted in two urban school districts in which 15 teachers taught 41 RY classes. Overall, implementation fidelity was high with an average 90% of core lessons being taught. Unexpectedly, increased quality of implementation predicted increased alcohol use and anger. Adherence (teaching more of the curriculum) predicted increased marijuana use, while exposure (student attendance) significantly increased bonding to high-risk peers, alcohol use and anger.

Low energy electron energy-loss spectroscopy of CF3X (X=Cl,Br)

We report threshold electron energy-loss spectra for the fluorohalomethanes CF3X (X=Cl,Br). Measurements were made at incident electron energies of 30 and 100 eV in energy-loss range of 4-14 eV, and at scattering angles of 4 degrees and 15 degrees. Several new electronic transitions are observed which are ascribable to excitation of low-lying states as well as are intrinsically overlapped in the molecules themselves. Assignments of these electronic transitions are suggested. These assignments are based on present spectroscopic and cross-section measurements, high-energy scattering spectra, and ab initio molecular orbital calculations. The calculated potential curves along the C-X bond show repulsive nature, suggesting that these transitions may lead to dissociation of the C-X bond. The present results are also compared with the previous ones for CF3H, CF4, and CF3I.

Metal specificity of an iron-responsive element in Alzheimer's APP mRNA 5'untranslated region, tolerance of SH-SY5Y and H4 neural cells to desferrioxamine, clioquinol, VK-28, and a piperazine chelator

Iron closely regulates the expression of the Alzheimer's Amyloid Precursor Protein (APP) gene at the level of message translation by a pathway similar to iron control of the translation of the ferritin L- and H mRNAs by Iron-responsive Elements in their 5' untranslated regions (5'UTRs). Using transfection based assays in SH-SY5Y neuroblastoma cells we tested the relative efficiency by which iron, copper and zinc up-regulate IRE activity in the APP 5'UTR. Desferrioxamine (high affinity Fe3+ chelator), (ii) clioquinol (low affinity Fe/Cu/Zn chelator), (iii) piperazine-1 (oral Fe chelator), (iv) VK-28 (oral Fe chelator), were tested for their relative modulation of APP 5' UTR directed translation of a luciferase reporter gene. Iron chelation based therapeutic strategies for slowing the progression of Alzheimer's disease (and other neurological disorders that manifest iron imbalance) are discussed with regard to the relative neural toxic action of each chelator in SH-SY5Y cells and in H4 glioblastoma cells.

Clinical characteristics and prognostic factors in diffuse large B-cell lymphoma with bone marrow involvement

7588

Background: Although several studies have been reported about non-Hodgkin’s lymphomas (NHL) with bone marrow (BM) involvement, most of them have not performed immunophenotypic studies and contained heterogeneous NHL histologies. Until now, only a few studies with small sample sizes have been reported about clinical characteristics and prognostic factors in diffuse large B-cell lymphoma (DLBCL) with BM involvement. Methods: Between January 1993 and March 2004, 486 patients were diagnosed with DLBCL. Among 84 DLBCL patients who had BM involvement at initial diagnosis, 9 were not ineligible because of the lack of clinical data or unavailability of BM specimen. So, clinical factors and patterns of BM involvement of 75 patients were analyzed in this study. Results: At initial diagnosis, the median age was 57 years (range: 25∼79). In addition to BM, lymph nodes (76%), spleen (23%), Waldeyer’s ring (19%), gastrointestinal tract (16%), lung/pleura (15%), bone (15%), central nervous system (9%), nasal cavity (8%) and liver (7%) were also involved. Among 75 patients, 67 patients received anthracycline-containing chemotherapy; 4 patients received non-anthracycline-containing chemotherapy and 4 could not receive systemic chemotherapy because of combined medical conditions. The median survival was 32.3 months (5-year overall survival [OS]: 38%). In univariate analysis for prognostic factors, high-intermediate or high international prognostic index (IPI), B-symptoms, leucopenia, anemia, thrombocytopenia, pattern of BM involvement (interstitial or diffuse pattern), > 10% replacement of BM area by lymphoma cells, > 10% of large cell infiltration in BM-involved area by lymphoma at initial diagnosis were associated with poor OS (p < 0.05). Multivariate analysis indicated that > 10% replacement of BM area by lymphoma cells (p < 0.001), peripheral thrombocytopenia (p = 0.001) and high-intermediate or high IPI (p = 0.042) were independent predictors of poor OS. Conclusions: To our knowledge, this is the largest study about DLBCL patients with BM involvement. The BM areas involved by lymphoma cells, peripheral thrombocytopenia and IPI at initial diagnosis are independent prognostic factors in these patients.

No significant financial relationships to disclose.

Preclinical development of a novel inhibitor of oncogenic B-Raf

13056

Background: The discovery of oncogenic B-Raf mutations in a majority of patients with metastatic melanoma, and in many tumors from patients with colorectal cancer and other cancers, presents the opportunity to develop oncogene-selective inhibitors with a favorable safety profile. Methods: Guided by co-crystallography, a novel chemical scaffold has been developed into a series of potent inhibitors of oncogenic B-Raf with selectivity versus wild-type B-Raf. From this series, a potent inhibitor has been chosen as a candidate for development. Results: Consistent with the structure-guided approach, this compound shows pronounced selectivity versus a wide array of over 70 other kinases covering all branches of the kinome. This selectivity translates to a wide cellular therapeutic index: inhibition of proliferation of a panel of cell lines bearing the V600E oncogenic B-Raf mutation occurs at IC50s ranging from 40–400 nM while inhibition of cell lines lacking oncogenic B-Raf occurs at IC50s greater than 6500 nM. This cell-based selectivity for the oncogenic B-Raf is greater than the selectivity shown in biochemical assays, supporting that tumor cells bearing the oncogenic B-Raf protein are more dependent on the MAP kinase pathway. Combination experiments with a series of cytotoxic and targeted clinical anti-cancer agents reveal multiple examples of synergistic inhibition of proliferation in vitro, and this synergy generally appears selectively in oncogenic B-Raf-bearing cells. The good oral bioavailability (F > 70%) allows for prolonged exposure in both rodents and non-rodents. Robust efficacy is evident in a murine COLO205 tumor xenograft model, with once-daily oral dosing at 20 mg/kg over 14 days resulting in > 80% inhibition of tumor growth with no effect on body weight. Conclusions: Since this compound is highly selective and targets a B-Raf variant that is absent in all non-transformed cells, it may have a broad therapeutic index, alone or in combination, for the treatment of patients with V600E oncogenic B-Raf tumors.

[Table: see text]

Fast imaging with the MMME sequence

The multiple-modulation-multiple-echo sequence, previously used for rapid measurement of diffusion, is extended to a method for single shot imaging. Removing the gradient switching requirement during the application of RF pulses by a constant frequency encoding gradient can shorten experiment time for ultrafast imaging. However, having the gradient on during the pulses gives rise to echo shape variations from off-resonance effects, which make the image reconstruction difficult. In this paper, we propose a simple method to deconvolve the echo shape variation from the true one-dimensional image. This method is extended to two-dimensional imaging by adding phase encoding gradients between echoes during the acquisition period to phase encode each echo separately. Slice selection is achieved by a frequency selective pulse at the beginning of the sequence. Imaging speed is mainly limited by the phase encoding gradients' switching times and echo overlap when echo spacing is very short. This technique can produce a single-shot image of sub-millimeter resolution in 5 ms.

Superconducting phase coherent electron transport in proximity conical ferromagnets

We report superconducting phase-periodic conductance oscillations in ferromagnetic wires with interfaces to conventional superconductors. The ferromagnetic wires were made of Ho, a conical ferromagnet. The distance between the interfaces was much larger than the singlet superconducting penetration depth. We explain the observed oscillations as due to the long-range penetration of an unusual helical triplet component of the order parameter that is generated at the superconductor/ferromagnet interfaces and maintained by the intrinsic rotating magnetization of Ho.

Repeated brief epileptic seizures by pentylenetetrazole cause neurodegeneration and promote neurogenesis in discrete brain regions of freely moving adult rats

Recurrent epileptic seizures are known to provoke various forms of cellular reorganization in the brains of humans and experimental animals. However, little is known about the mechanism of neuronal cell death resulting from epileptic seizures elicited by GABA antagonists. In the present study, we explored the effect on the central nervous systems of freely moving adult rats, of repeated brief epileptic seizures induced by systemic injection of pentylenetetrazole, a GABA-A receptor antagonist. Starting with minor convulsions, repeated epileptic seizures elicited a progressive increase in seizure severity, culminating in the fully kindled state. Histological examination showed that the epileptic seizures caused overt neuronal cell death in the limbic system, including the hippocampus and amygdala, and its adjoining cortex. During the recurrent epileptic seizures, neurogenesis occurred in the subgranular zone of the hippocampus, the subventricular zone of the lateral ventricle, and the amygdala. This type of pentylenetetrazole-induced neurogenesis was seen at an early stage of epileptogenesis in some regions in which massive cell loss was not evident. This suggests that neurogenesis is not a secondary consequence of neuronal cell death, but rather an independent effect of recurrent epileptic seizures.

Genetic variation at the perilipin locus is associated with changes in serum free fatty acids and abdominal fat following mild weight loss

OBJECTIVE

Perilipin (PLIN) is a class of protein-coating lipid droplets in adipocytes. We aimed to examine the association between common single-nucleotide polymorphisms (SNPs) at PLIN locus with circulating free fatty acid (FFA) and abdominal fat distribution in response to weight loss.

METHODS

Non-diabetic/overweight-obese Koreans (n=177) participated in a 12-week calorie restriction (-300kcal/day) program. Seven SNPs (6209T>C, 10076C>G, 10171A>T, 11482G>A, 13042A>G, 13048C>T and 14995A>T), abdominal fat areas (visceral/subcutaneous fat areas at 1st lumbar and 4th lumbar levels), serum lipids, glucose, insulin, FFA, oxidized low-density lipoprotein (LDL) and urinary 8-epi-prostaglandin F(2alpha) (PGF(2alpha)) were examined.

RESULTS

Single-nucleotide polymorphisms 10076C>G/10171A>T showed the strongest positive linkage disequilibrium (LD) (D'=0.923, R (2)=0.839, P<0.001) and SNPs11482G>A/14995A>T showed moderate positive LD (D'=0.824, R (2)=0.578, P<0.001). Calorie restriction induced 4.6% weight loss with significant abdominal fat reduction. In response to weight loss, subjects with nCA/nCA haplotypes at SNPs 10076C>G/10171A>T showed greater reduction in FFA levels than those with CA/CA haplotype (CA/CA: C/C at SNP 10076 and A/A at SNP 10171, nCA: non-CA haplotype carrier). On the other hand, subjects with nGA/nGA haplotype at SNPs 11482G>A/14995A>T had increased FFA levels with a rapid loss in abdominal fat, whereas GA/GA haplotype carriers had reduction in FFA levels. These results still remained significant after adjusting for age, gender and BMI. Prostaglandin F(2alpha) and oxidized LDL were also more reduced in GA/GA haplotype carriers than in nGA haplotype carriers. This effect remained significant after adjusting for baseline level, age, gender and BMI. Paradoxically, nGA haplotype carriers had increased levels of urinary PGF(2alpha) after weight reduction.

CONCLUSION

Fasting plasma FFA changes following a modest weight loss in overweight-obese subjects are influenced by the genetic variability at the PLIN locus. Furthermore, circulating FFA changes rather than body fat itself may determine changes in lipid peroxides such as urinary PGF(2alpha) and oxidized LDL.

Production and characterization of guinea pig recombinant gamma interferon and its effect on macrophage activation

Gamma interferon (IFN-gamma) plays a critical role in the protective immune responses against mycobacteria. We previously cloned a cDNA coding for guinea pig IFN-gamma (gpIFN-gamma) and reported that BCG vaccination induced a significant increase in the IFN-gamma mRNA expression in guinea pig cells in response to living mycobacteria and that the virulent H37Rv strain of Mycobacterium tuberculosis stimulated less IFN-gamma mRNA than did the attenuated H37Ra strain. In this study, we successfully expressed and characterized recombinant gpIFN-gamma with a histidine tag at the N terminus (His-tagged rgpIFN-gamma) in Escherichia coli. rgpIFN-gamma was identified as an 18-kDa band in the insoluble fraction; therefore, the protein was purified under denaturing conditions and renatured. N-terminal amino acid sequencing of the recombinant protein yielded the sequence corresponding to the N terminus of His-tagged gpIFN-gamma. The recombinant protein upregulated major histocompatibility complex class II expression in peritoneal macrophages. The antiviral activity of rgpIFN-gamma was demonstrated with a guinea pig fibroblast cell line (104C1) infected with encephalomyocarditis virus. Interestingly, peritoneal macrophages treated with rgpIFN-gamma did not produce any nitric oxide but did produce hydrogen peroxide and suppressed the intracellular growth of mycobacteria. Furthermore, rgpIFN-gamma induced morphological alterations in cultured macrophages. Thus, biologically active rgpIFN-gamma has been successfully produced and characterized in our laboratory. The study of rgpIFN-gamma will further increase our understanding of the cellular and molecular responses induced by BCG vaccination in the guinea pig model of pulmonary tuberculosis.

Scoring and staging systems using cox linear regression modeling and recursive partitioning

OBJECTIVES

Scoring and staging systems are used to determine the order and class of data according to predictors. Systems used for medical data, such as the Child-Turcotte-Pugh scoring and staging systems for ordering and classifying patients with liver disease, are often derived strictly from physicians' experience and intuition. We construct objective and data-based scoring/staging systems using statistical methods.

METHODS

We consider Cox linear regression modeling and recursive partitioning techniques for censored survival data. In particular, to obtain a target number of stages we propose cross-validation and amalgamation algorithms. We also propose an algorithm for constructing scoring and staging systems by integrating local Cox linear regression models into recursive partitioning, so that we can retain the merits of both methods such as superior predictive accuracy, ease of use, and detection of interactions between predictors. The staging system construction algorithms are compared by cross-validation evaluation of real data.

RESULTS

The data-based cross-validation comparison shows that Cox linear regression modeling is somewhat better than recursive partitioning when there are only continuous predictors, while recursive partitioning is better when there are significant categorical predictors. The proposed local Cox linear recursive partitioning has better predictive accuracy than Cox linear modeling and simple recursive partitioning.

CONCLUSIONS

This study indicates that integrating local linear modeling into recursive partitioning can significantly improve prediction accuracy in constructing scoring and staging systems.