Real-time determination of enantiomeric and isomeric content using photoelectron elliptical dichroism.

The fast and accurate analysis of chiral chemical mixtures is crucial for many applications but remains challenging. Here we use elliptically-polarized femtosecond laser pulses at high repetition rates to photoionize chiral molecules. The 3D photoelectron angular distribution produced provides molecular fingerprints, showing a strong forward-backward asymmetry which depends sensitively on the molecular structure and degree of ellipticity. Continuously scanning the laser ellipticity and analyzing the evolution of the rich, multi-dimensional molecular signatures allows us to observe real-time changes in the chemical and chiral content present with unprecedented speed and accuracy. We measure the enantiomeric excess of a compound with an accuracy of 0.4% in 10 min acquisition time, and follow the evolution of a mixture with an accuracy of 5% with a temporal resolution of 3 s. This method is even able to distinguish isomers, which cannot be easily distinguished by mass-spectrometry.

Attosecond time-resolved photoelectron holography.

Ultrafast strong-field physics provides insight into quantum phenomena that evolve on an attosecond time scale, the most fundamental of which is quantum tunneling. The tunneling process initiates a range of strong field phenomena such as high harmonic generation (HHG), laser-induced electron diffraction, double ionization and photoelectron holography-all evolving during a fraction of the optical cycle. Here we apply attosecond photoelectron holography as a method to resolve the temporal properties of the tunneling process. Adding a weak second harmonic (SH) field to a strong fundamental laser field enables us to reconstruct the ionization times of photoelectrons that play a role in the formation of a photoelectron hologram with attosecond precision. We decouple the contributions of the two arms of the hologram and resolve the subtle differences in their ionization times, separated by only a few tens of attoseconds.

JAK-STAT and G-protein-coupled receptor signaling pathways are frequently altered in epitheliotropic intestinal T-cell lymphoma.

Epitheliotropic intestinal T-cell lymphoma (EITL, also known as type II enteropathy-associated T-cell lymphoma) is an aggressive intestinal disease with poor prognosis and its molecular alterations have not been comprehensively characterized. We aimed to identify actionable easy-to-screen alterations that would allow better diagnostics and/or treatment of this deadly disease. By performing whole-exome sequencing of four EITL tumor-normal pairs, followed by amplicon deep sequencing of 42 tumor samples, frequent alterations of the JAK-STAT and G-protein-coupled receptor (GPCR) signaling pathways were discovered in a large portion of samples. Specifically, STAT5B was mutated in a remarkable 63% of cases, JAK3 in 35% and GNAI2 in 24%, with the majority occurring at known activating hotspots in key functional domains. Moreover, STAT5B locus carried copy-neutral loss of heterozygosity resulting in the duplication of the mutant copy, suggesting the importance of mutant STAT5B dosage for the development of EITL. Dysregulation of the JAK-STAT and GPCR pathways was also supported by gene expression profiling and further verified in patient tumor samples. In vitro overexpression of GNAI2 mutants led to the upregulation of pERK1/2, a member of MEK-ERK pathway. Notably, inhibitors of both JAK-STAT and MEK-ERK pathways effectively reduced viability of patient-derived primary EITL cells, indicating potential therapeutic strategies for this neoplasm with no effective treatment currently available.

The uric acid transporter SLC2A9 is a direct target gene of the tumor suppressor p53 contributing to antioxidant defense.

Only humans and higher primates have high uric acid blood levels. Although high uric acid causes gout, it has been linked with human longevity because of its hypothetical antioxidant function. Recent studies reveal that p53 has significant roles in cellular metabolism. One example of this is an antioxidant function that potentially contributes to tumor suppression. Here, we reported a first beneficial link between p53 and uric acid. We identified the uric acid transporter SLC2A9 (also known as GLUT9) as a direct p53 target gene and a key downstream effector in the reduction of reactive oxygen species (ROS) through transporting uric acid as a source of antioxidant. Oxidative stress induced SLC2A9 expression in a p53-dependent manner, and inhibition of SLC2A9 by small interfering RNA (siRNA) or anti-gout drugs such as probenecid significantly increased ROS levels in an uric acid-dependent manner and greatly sensitized cancer cells to chemotherapeutic drugs. Conversely, expression of SLC2A9 reduced ROS and protected against DNA damage and cell death, suggesting its antioxidant function. The increased production of ROS because of p53 loss was rescued by SLC2A9 expression. Furthermore, decreased SLC2A9 expression was observed in several cancer types and was associated with a poorer prognosis. Our findings suggest that the p53-SLC2A9 pathway is a novel antioxidant mechanism that uses uric acid to maintain ROS homeostasis and prevent accumulation of ROS-associated damage that potentially contributes to cancer development.

Effect of a short dry period on milk yield and content, colostrum quality, fertility, and metabolic status of Holstein cows.

We evaluated the effect of shortening the dry period (DP) on milk and energy-corrected milk (ECM) yields, milk components, colostrum quality, metabolic status, and reproductive parameters. Primiparous (n=372) and multiparous (n=400) Israeli Holstein cows from 5 commercial dairy herds were subjected to a 60-d or 40-d DP. Cows within each herd were paired according to milk production, age, days in milk, and expected calving. Analysis of the data from all cows, irrespective of age, revealed significant differences in milk and ECM yields that favored the 60-d DP, with a prominent effect in 2 of 5 examined herds. In primiparous cows, milk and ECM yields were similar between groups in 4 of 5 farms. In multiparous cows undergoing a 60-d (vs. 40-d) DP, milk and ECM yields were higher in 3 herds. These differences could not be explained by milk and ECM yields in cows diagnosed with metritis, ketosis, and mastitis (defined by a somatic cell count threshold of 250,000 cell/mL), distribution of infected and noninfected cows, or new infections during DP and after calving. Including the milk and ECM yields from an average of 19.55 d from the previous lactation revealed higher milk and ECM yields for 40-d (vs. 60-d) DP cows in all herds. Analyzing 2 consecutive lactations revealed similar milk and ECM yields between groups in 4 out of 5 herds. In 1 herd, yields were higher in the 40-d compared with the 60-d DP group. One week after calving, the nonesterified fatty acid concentrations of 40-d DP cows were significantly lower than those of 60-d DP cows, indicating better postpartum energy balance. Colostrum quality, measured as IgG concentration, did not differ between the 2 DP groups. Cows assigned to 40-d DP had better reproductive performance, as reflected by fewer days to first insemination, a lower proportion with >90 d to first insemination, and fewer days to pregnancy. With respect to primiparous cows, a short DP increased conception rate after first artificial insemination and decreased the proportion of nonpregnant cows after 150 d in milk. In light of these findings, we suggest that a short DP be applied for its economic and physiological benefits. This is highly relevant to dairy herds located in regions such as Israel, Spain, and Florida that suffer from reduced milk production during the hot season.

Alterations in metabolic pathways and networks in Alzheimer's disease.

The pathogenic mechanisms of Alzheimer's disease (AD) remain largely unknown and clinical trials have not demonstrated significant benefit. Biochemical characterization of AD and its prodromal phase may provide new diagnostic and therapeutic insights. We used targeted metabolomics platform to profile cerebrospinal fluid (CSF) from AD (n=40), mild cognitive impairment (MCI, n=36) and control (n=38) subjects; univariate and multivariate analyses to define between-group differences; and partial least square-discriminant analysis models to classify diagnostic groups using CSF metabolomic profiles. A partial correlation network was built to link metabolic markers, protein markers and disease severity. AD subjects had elevated methionine (MET), 5-hydroxyindoleacetic acid (5-HIAA), vanillylmandelic acid, xanthosine and glutathione versus controls. MCI subjects had elevated 5-HIAA, MET, hypoxanthine and other metabolites versus controls. Metabolite ratios revealed changes within tryptophan, MET and purine pathways. Initial pathway analyses identified steps in several pathways that appear altered in AD and MCI. A partial correlation network showed total tau most directly related to norepinephrine and purine pathways; amyloid-ß (Ab42) was related directly to an unidentified metabolite and indirectly to 5-HIAA and MET. These findings indicate that MCI and AD are associated with an overlapping pattern of perturbations in tryptophan, tyrosine, MET and purine pathways, and suggest that profound biochemical alterations are linked to abnormal Ab42 and tau metabolism. Metabolomics provides powerful tools to map interlinked biochemical pathway perturbations and study AD as a disease of network failure.

Low self-awareness of ADHD in adults using a self-report screening questionnaire.

INTRODUCTION: Awareness of attention deficit hyperactivity disorder (ADHD) in adults has been growing over the last decade. One of the most interesting issues related to this topic is these adults' self-awareness of their ADHD symptoms and their estimation of their own impairments. Our hypothesis while studying young adult ADHD populations was that there would be a significant difference between their self-report and their clinical assessment. METHOD: One hundred and three students volunteered for this study. In order to validate our ADHD screening questionnaire (ADHD-SQ), and to assess the level of awareness they have of their own symptoms, participants underwent a complete clinical assessment for ADHD. They were divided into a control group (n=24), and an ADHD study group (n=79), which in turn was composed of two sub-groups, one comprising 24 ADHD predominantly inattentive (ADHD-I) and the other 55 ADHD combined type (ADHD-C). RESULTS: Factor analysis yielded two factors explaining 41% of the variance. The Inattention (IA) subscale score tended to be higher in both ADHD sub-groups as compared to the control group (6.5 ± 2.1 vs. 2.34 ± 2.3 with P<0.001), with no significant difference between the two ADHD sub-groups. Hyperactivity Impulsivity (HI) subscale was significantly higher for the ADHD-C sub-group than in the ADHD-I sub-group, whose score was similar to that of the control group (control: 1.6 ± 2.1; ADHD-I: 1.55 ± 1.0; ADHD-C: 4.5 ± 2.6, P<0.0001). Receiver Operating Characteristics (ROC) analysis showed similar results. The area under the curve (AUC) of IA subscale score was 0.90 (95% confidence: 0.83-0.96) and for HI subscale score was 0.75, (95% confidence: 0.63-0.86). Classification into groups used a cut-off point of 3+ items out of nine, in the SQ and 6+ items out of nine in the clinical assessment. These two classifications showed 68% agreement (46% sensitivity and 95% specificity). In both ADHD sub-groups, the self-reported average number of positive symptoms per student was relatively low for both clusters; this phenomenon was pronounced in the specific subtypes. The self-rated HI cluster score was considerably low in the ADHD-C sub-group (4.5 ± 2.6), and the IA one was particularly low in the ADHD-IADHD-I sub-group (5.9 ± 1.9). CONCLUSION: This study's results indicate that ADHD symptoms are under-reported for both inattentive and hyperactive-impulsive clusters, indicating that adults with ADHD tend to under-estimate their own ADHD-related impairments. We suggest that this questionnaire may be used both in research and academic settings to help counsellors and students to obtain early indication of ADHD and to refer students suspected of having ADHD to full clinical assessment.

Altered interactions of tryptophan metabolites in first-episode neuroleptic-naive patients with schizophrenia.

Schizophrenia is characterized by complex and dynamically interacting perturbations in multiple neurochemical systems. In the past, evidence for these alterations has been collected piecemeal, limiting our understanding of the interactions among relevant biological systems. Earlier, both hyper- and hyposerotonemia were variously associated with the longitudinal course of schizophrenia, suggesting a disturbance in the central serotonin (5-hydroxytryptamine (5-HT)) function. Using a targeted electrochemistry-based metabolomics platform, we compared metabolic signatures consisting of 13 plasma tryptophan (Trp) metabolites simultaneously between first-episode neuroleptic-naive patients with schizophrenia (FENNS, n=25) and healthy controls (HC, n=30). We also compared these metabolites between FENNS at baseline (BL) and 4 weeks (4w) after antipsychotic treatment. N-acetylserotonin was increased in FENNS-BL compared with HC (P=0.0077, which remained nearly significant after Bonferroni correction). N-acetylserotonin/Trp and melatonin (Mel)/serotonin ratios were higher, and Mel/N-acetylserotonin ratio was lower in FENNS-BL (all P-values<0.0029), but not after treatment, compared with HC volunteers. All three groups had highly significant correlations between Trp and its metabolites, Mel, kynurenine, 3-hydroxykynurenine and tryptamine. However, in the HC, but in neither of the FENNS groups, serotonin was highly correlated with Trp, Mel, kynurenine or tryptamine, and 5-hydroxyindoleacetic acid (5HIAA) was highly correlated with Trp, Mel, kynurenine or 3-hydroxykynurenine. A significant difference between HC and FENNS-BL was further shown only for the Trp-5HIAA correlation. Thus, some metabolite interactions within the Trp pathway seem to be altered in the FENNS-BL patients. Conversion of serotonin to N-acetylserotonin by serotonin N-acetyltransferase may be upregulated in FENNS patients, possibly related to the observed alteration in Trp-5HIAA correlation. Considering N-acetylserotonin as a potent antioxidant, such increases in N-acetylserotonin might be a compensatory response to increased oxidative stress, implicated in the pathogenesis of schizophrenia.

Y chromosome gr/gr deletions are a risk factor for low semen quality.

BACKGROUND: Subfertility affects one in eight couples. In up to 50% of cases, the male partner has low semen quality. Four Y chromosome deletions, i.e. Azoospermia factor a (AZFa), P5/proximal-P1 (AZFb), P5/distal-P1 and AZFc deletions, are established causes of low semen quality. Whether a recently identified partial AZFc deletion, the gr/gr deletion, also causes low semen quality is at present unclear. METHODS: We used a dual approach to review the effect of the gr/gr deletion on semen quality. First, we conducted a systematic review and meta-analysis of previous association studies, to compare the prevalence of gr/gr deletions between azoo-/oligozoospermic men and normozoospermic men. Secondly, we studied a cohort of 1041 male partners of subfertile couples unselected for semen quality. We employed a cross-sectional design by screening all men for the gr/gr deletion and comparing the semen quality of men with and without the gr/gr deletion. RESULTS: Seven studies were included in the meta-analysis. The gr/gr deletion was significantly more prevalent among azoo-/oligozoospermic men than among normozoospermic men (OR 2.4, 95% CI 1.75-3.30). In our cohort, 25 men carried a gr/gr deletion. Men with this genotype had a lower sperm concentration (median 34 x 10(6)/ml versus 53 x 10(6)/ml, P = 0.017), total sperm count (median 108 x 10(6) versus 152 x 10(6), P = 0.006) and total motile sperm count (median 20 x 10(6) versus 50 x 10(6), P = 0.010) than men without the gr/gr deletion. CONCLUSION: Y chromosome gr/gr deletions significantly reduce sperm counts and are thus associated with low semen quality.

Downregulation of Sef, an inhibitor of receptor tyrosine kinase signaling, is common to a variety of human carcinomas.

Carcinomas are tumors of epithelial origin accounting for over 80% of all human malignancies. A substantial body of evidence implicates oncogenic signaling by receptor tyrosine kinases (RTKs) in carcinoma development. Here we investigated the expression of Sef, a novel inhibitor of RTK signaling, in normal human epithelial tissues and derived malignancies. Human Sef (hSef) was highly expressed in normal epithelial cells of breast, prostate, thyroid gland and the ovarian surface. By comparison, substantial downregulation of hSef expression was observed in the majority of tumors originating from these epithelia. Among 186 primary carcinomas surveyed by RNA in situ hybridization, hSef expression was undetectable in 116 cases including 72/99 (73%) breast, 11/16 (69%) thyroid, 16/31 (52%) prostate and 17/40 (43%) ovarian carcinomas. Moderate reduction of expression was observed in 17/186, and marked reduction in 40/186 tumors. Only 13/186 cases including 12 low-grade and one intermediate grade tumor retained high hSef expression. The association of hSef downregulation and tumor progression was statistically significant (P<0.001). Functionally, ectopic expression of hSef suppressed proliferation of breast carcinoma cells, whereas inhibition of endogenous hSef expression accelerated fibroblast growth factor and epidermal growth factor-dependent proliferation of cervical carcinoma cells. The inhibitory effect of hSef on cell proliferation combined with consistent downregulation in human carcinoma indicates a tumor suppressor-like role for hSef, and implicates loss of hSef expression as a common mechanism in epithelial neoplasia.

The AZFc region of the Y chromosome features massive palindromes and uniform recurrent deletions in infertile men.

Deletions of the AZFc (azoospermia factor c) region of the Y chromosome are the most common known cause of spermatogenic failure. We determined the complete nucleotide sequence of AZFc by identifying and distinguishing between near-identical amplicons (massive repeat units) using an iterative mapping-sequencing process. A complex of three palindromes, the largest spanning 3 Mb with 99.97% identity between its arms, encompasses the AZFc region. The palindromes are constructed from six distinct families of amplicons, with unit lengths of 115-678 kb, and may have resulted from tandem duplication and inversion during primate evolution. The palindromic complex contains 11 families of transcription units, all expressed in testis. Deletions of AZFc that cause infertility are remarkably uniform, spanning a 3.5-Mb segment and bounded by 229-kb direct repeats that probably served as substrates for homologous recombination.

Synthesis of alpha-fluorocarboxylates from the corresponding acids using acetyl hypofluorite.

alpha-Fluorocarboxylic esters and acids were synthesized in good yields. The corresponding esters and acids were converted to their ketene acetals, and these enol derivatives reacted with AcOF made directly from fluorine. This route circumvents the problems associated with nucleophilic fluorinations such as various eliminations and rearrangements. alpha- and beta-branched carboxylic acid derivatives that cannot be directly fluorinated gave by this electrophilic fluorination the corresponding alpha-fluoro derivatives in good yield. Both the fluorination reaction and the preparation of AcOF are fast and suitable for [18]F incorporation into acids and esters needed for working with PET. alpha-Fluoroibuprofen (20) and methyl 2-fluoro-3,3,3-triphenylpropionate (32) are two examples of this general reaction.

Management strategies for pyoderma gangrenosum: case studies and review of literature.

Pyoderma gangrenosum (PG) is a systemic disease with cutaneous manifestations consisting of necrotizing ulceration. The etiology of PG is controversial, and optimal management strategies have not been established. Current management is primarily medical to control the systemic inflammatory process, with occasional surgical intervention at the ulcer site. Based on the current literature and on the authors' clinical experience, the optimal outcome depends on early diagnoses and a combination of medical and surgical therapy. Initial management is directed toward medical control of the inflammatory process and local wound care. Surgical strategies involve recipient site preparation via local wound care and serial allograft followed by autologous skin graft or muscle flap coverage when necessary. Long-term wound stabilization is obtained only through control of the systemic and local inflammatory process.

BrF3, an underutilized reagent in organic chemistry: a novel C-C-N to C-N-C rearrangement.

Little is known about bromine trifluoride in organic chemistry. Under the right conditions, it can be a useful tool and generate a new and unprecedented chemistry. Thus, when reacted with oxime methyl ethers of alpha-ketoesters, BrF3 was able to convert the oxime group into a CF2 group and through a new type of rearrangement cause a shift of the carboxylate group to the nitrogen atom. The novel structure of the alpha,alpha-difluorocarbamate was also proven by 15N NMR as demonstrated for compounds 3, 8, 9, 12, 15, and 18. Another novel "double rearrangement" was observed during the formation of 19. Dynamic 19F NMR experiments indicate a high nitrogen inversion-rotation (NIR) barrier for these novel carbamates of about 12.5 kcal/mol.

A physical map of the human Y chromosome.

The non-recombining region of the human Y chromosome (NRY), which comprises 95% of the chromosome, does not undergo sexual recombination and is present only in males. An understanding of its biological functions has begun to emerge from DNA studies of individuals with partial Y chromosomes, coupled with molecular characterization of genes implicated in gonadal sex reversal, Turner syndrome, graft rejection and spermatogenic failure. But mapping strategies applied successfully elsewhere in the genome have faltered in the NRY, where there is no meiotic recombination map and intrachromosomal repetitive sequences are abundant. Here we report a high-resolution physical map of the euchromatic, centromeric and heterochromatic regions of the NRY and its construction by unusual methods, including genomic clone subtraction and dissection of sequence family variants. Of the map's 758 DNA markers, 136 have multiple locations in the NRY, reflecting its unusually repetitive sequence composition. The markers anchor 1,038 bacterial artificial chromosome clones, 199 of which form a tiling path for sequencing.

A simple procedure for the analysis of single nucleotide polymorphisms facilitates map-based cloning in Arabidopsis.

We developed a modified allele-specific PCR procedure for assaying single nucleotide polymorphisms (SNPs) and used the procedure (called SNAP for single-nucleotide amplified polymorphisms) to generate 62 Arabidopsis mapping markers. SNAP primers contain a single base pair mismatch within three nucleotides from the 3' end of one allele (the specific allele) and in addition have a 3' mismatch with the nonspecific allele. A computer program called SNAPER was used to facilitate the design of primers that generate at least a 1,000-fold difference in the quantity of the amplification products from the specific and nonspecific SNP alleles. Because SNAP markers can be readily assayed by electrophoresis on standard agarose gels and because a public database of over 25,000 SNPs is available between the Arabidopsis Columbia and Landsberg erecta ecotypes, the SNAP method greatly facilitates the map-based cloning of Arabidopsis genes defined by a mutant phenotype.

Giant plexiform neurofibroma of the back.

Complete excision of a giant neurofibroma can be technically difficult. Thorough preoperative planning with magnetic resonance imaging, computed tomography, and arteriography are indicated to define the extent of the mass and to facilitate operative planning. By following the treatment guidelines discussed in this case report, the authors feel that these tumors can be excised safely with minimal morbidity.

Deletion of azoospermia factor a (AZFa) region of human Y chromosome caused by recombination between HERV15 proviruses.

Deletion of any of three regions of the human Y chromosome results in spermatogenic failure and infertility. We previously sequenced one of these regions, azoospermia factor a (AZFa) and found that it spanned approximately 800 kb. By sequence-tagged site (STS) content mapping, we roughly defined deletion breakpoints in two unrelated, azoospermic men with AZFa deletions. The positions of proximal and distal breakpoints were similar in the two men. Hypothesizing that the deletions might have been generated by homologous recombination, we searched electronically for DNA sequence similarities between the proximal and distal breakpoint regions. These comparisons revealed the most striking sequence similarities anywhere along or near the AZFa region. In the proximal breakpoint region, we identified a 10 kb provirus of the recently defined HERV15 class of endogenous retroviruses. In the distal breakpoint region, we found a second HERV15 provirus, 94% identical in DNA sequence to the first and in the same orientation. (A partial LINE insertion in this distal provirus proved to be the basis of the previously described DYS11/p12f polymorphism.) The AZFa deletions in the two men differed slightly, but all breakpoints fell within the HERV15 proviruses. Indeed, sequencing of deletion junctions from the two men revealed that homologous recombination had occurred within large domains of absolute sequence identity between the proximal and distal proviruses. When combined with published STS mapping data for other AZFa-deleted men, our findings suggest that recombination between these two HERV15 proviruses could account for most AZFa deletions.