122 research outputs found
Stereoselective Synthesis of the Proposed C79-C104 Fragment of Symbiodinolide
Stereoselective and streamlined synthesis of the proposed C79-C104 fragment 2 of symbiodinolide (1), a polyol marine natural product with a molecular weight of 2860, was achieved. In the synthetic route, the proposed C79-C104 fragment 2 was synthesized by utilizing a Julia-Kocienski olefination and subsequent Sharpless asymmetric dihydroxylation as key transformations in a convergent manner. Detailed comparison of the 13 C NMR chemical shifts between the natural product and the synthetic C79-C104 fragment 2 revealed that the stereostructure at the C91-C99 carbon chain moiety of symbiodinolide (1) should be reinvestigated
Stereodivergent Synthesis and Stereochemical Reassignment of the C79-C104 Fragment of Symbiodinolide
We have synthesized eight possible diastereoisomers 3 a-h of the C79-C97 fragment of symbiodinolide (1) in a stereodivergent manner by utilizing a dithiane addition to the aldehyde as a key step. Comparison of the 13 C NMR chemical shifts of the natural product 1 and the synthetic products 3 a-h indicated that the relative stereostructure of this fragment in symbiodinolide (1) is that represented in 3 a or f. We have stereodivergently synthesized eight possible diastereoisomers of the C94-C104 fragment 4 a-h, and we have compared their 13 C NMR chemical shifts with those of the natural product, which established the relative stereochemistry of this fragment to be that described in diastereoisomers 4 a or e. By combining the stereostructural outcomes of the C79-C97 and C94-C104 fragments, we have proposed four candidate compounds of the C79-C104 fragment 2 a-d. We also synthesized diastereoisomers 2 a and b (2 a in the preceding article; Chem. Eur. J. 2015, DOI: 10.1002/chem.201503880) by a Julia-Kocienski olefination and diastereoisomers 2 c and d by a Wittig reaction. By comparing the 13 C NMR chemical shifts of natural symbiodinolide (1) with those of the synthetic products 2 a-d, we have reassigned the stereostructure of the C79-C104 fragment of natural product 1 to be that depicted in diastereoisomer 2 b
Cholelithiasis with a cholecystoduodenal fistula complicated with paroxysmal nocturnal hemoglobinuria
In cases of paroxysmal nocturnal hemoglobinuria (PNH), attention must be paid to potential complications such as thrombosis and hemolysis due to perioperative stress and infection from complement activation. Here we present the case of a 61-year-old Japanese woman with PNH. We made the diagnosis of PNH when she was 28 years old, and we administered repeated steroid medication and erythrocyte transfusion. The patient's cholecystocholedocholithiasis with a cholecystoduodenal fistula was diagnosed based on a survey of the right hypochondriac pain. We performed endoscopic nasobiliary drainage (ENBD) for the prophylaxis of perioperative infection, plus a cholecystectomy and fistulectomy. There were no complications, including hemolysis attack, infection, thrombosis with irrigation erythrocyte transfusion, steroid cover, or the need for heparin administration during the perioperative period. The reduction of the complement activation is necessary in the perioperative management of PNH patients. The prevention of the development of acidosis and hypoxemia, the selection of washed red blood cells, steroid use, appropriate infection measures and thrombosis prophylaxis are all important for the prevention of complications
p53 Expression in Pretreatment Specimen Predicts Response to Neoadjuvant Chemotherapy Including Anthracycline and Taxane in Patients with Primary Breast Cancer.
While clinical and pathologic responses are important prognostic parameters, biological markers from core needle biopsy (CNB) are needed to predict neoadjuvant chemotherapy (NAC) response, to individualize treatment, and to achieve maximal efficacy. We retrospectively evaluated the cases of 183 patients with primary breast cancer who underwent surgery after NAC (anthracycline and taxane) at the National Cancer Center Hospital (NCCH). We analyzed EGFR, HER2, and p53 expression and common clinicopathological features from the CNB and surgical specimens of these patients. These biological markers were compared between sensitive patients (pathological complete response;pCR) and insensitive patients (clinical no change;cNC and clinical progressinve disease;cPD). In a comparison between the 9 (5%) sensitive patients and 30 (16%) insensitive patients, overexpression of p53 but not overexpression of either HER2 or EGFR was associated with a good response to NAC. p53 (p=0.045) and histological grade 3 (p=0.011) were important and significant predictors of the response to NAC. The correspondence rates for histological type, histological grade 3, ER, PgR, HER2, p53, and EGFR in insensitive patients between CNB and surgical specimens were 70%, 73%, 67%, 70%, 80%, 93%, and 73%. The pathologic response was significantly associated with p53 expression and histological grade 3. The correspondence rate of p53 expression between CNB and surgical specimens was higher than that of other factors. We conclude that the level of p53 expression in the CNB was an effective and reliable predictor of treatment response to NAC
Ferromagnetism and giant magnetoresistance in the rare earth fullerides Eu6-xSrxC60
We have studied crystal structure, magnetism and electric transport
properties of a europium fulleride Eu6C60 and its Sr-substituted compounds,
Eu6-xSrxC60. They have a bcc structure, which is an isostructure of other M6C60
(M represents an alkali atom or an alkaline earth atom). Magnetic measurements
revealed that magnetic moment is ascribed to the divalent europium atom with S
= 7/2 spin, and a ferromagnetic transition was observed at TC = 10 - 14 K. In
Eu6C60, we also confirm the ferromagnetic transition by heat capacity
measurement. The striking feature in Eu6-xSrxC60} is very large negative
magnetoresistance at low temperature; the resistivity ratio \rho(H = 9
T)/\rho(H = 0 T) reaches almost 10^{-3} at 1 K in Eu6C60. Such large
magnetoresistance is the manifestation of a strong pi-f interaction between
conduction carriers on C60 and 4f electrons of Eu.Comment: 5 pages, 4 figure
Thermal expansion of single-walled carbon nanotube (SWNT) bundles: X-ray diffraction studies
Thermal expansion coefficient in single-walled carbon nanotube bundles was determined as (-0.15±0.20)×10-5 (1/K) for the tube diameter and (0.75±0.25)×10-5 (1/K) for the triangular lattice constant by means of x-ray scattering between 300 K to 950 K. The value for the intertube gap was (4.2±1.4)×10-5 (1/K), which is larger than 2.6×10-5 (1/K) for the c-axis thermal expansion in graphite. The results reveal the presence of a remarkably larger lattice anharmonicity in nanotube bundles than that of graphite. The small value for the tube diameter is consistent with the seamless tube structure formed by a strong covalent bond between carbon atoms comparable to that in graphite
Estrogen receptor (ER) mRNA expression and molecular subtype distribution in ER-negative/progesterone receptor-positive breast cancers
We examined estrogen receptor (ER) mRNA expression and molecular subtypes in stage I-III breast cancers that are progesterone receptor (PR) positive but ER and HER2 negative by immunohistochemistry (IHC) or fluorescent in situ hybridization. The ER, PR, and HER2 status was determined by IHC as part of routine clinical assessment (N = 501). Gene expression profiling was done with the Affymetrix U133A gene chip. We compared expressions of ESR1 and MKI67 mRNA, distribution of molecular subtypes by the PAM50 classifier, the sensitivity to endocrine therapy index, and the DLDA30 chemotherapy response predictor signature among ER/PR-positive (n = 223), ER-positive/PR-negative (n = 73), ER-negative/PR-positive (n = 20), and triple-negative (n = 185) cancers. All patients received neoadjuvant chemotherapy with an anthracycline and taxane and had adjuvant endocrine therapy only if ER or PR > 10 % positive. ESR1 expression was high in 25 % of ER-negative/PR-positive, in 79 % of ER-positive/PR-negative, in 96 % of ER/PR-positive, and in 12 % of triple-negative cancers by IHC. The average MKI67 expression was significantly higher in the ER-negative/PR-positive and triple-negative cohorts. Among the ER-negative/PR-positive patients, 15 % were luminal A, 5 % were Luminal B, and 65 % were basal like. The relapse-free survival rate of ER-negative/PR-positive patients was equivalent to ER-positive cancers and better than the triple-negative cohort. Only 20-25 % of the ER-negative/PR-positive tumors show molecular features of ER-positive cancers. In this rare subset of patients (i) a second RNA-based assessment may help identifying the minority of ESR1 mRNA-positive, luminal-type cancers and (ii) the safest clinical approach may be to consider both adjuvant endocrine and chemotherapy
Real-Time PCR Assay for the Diagnosis and Quantification of Co-infections by Diaporthe batatas and Diaporthe destruens in Sweet Potato
Foot rot disease caused by Diaporthe destruens (formerly Plenodomus destruens) has become a major concern for the production of sweet potato [Ipomoea batatas (L.) Lam.] in Japan. A related fungus Diaporthe batatas, which causes dry rot disease of sweet potato, is native and is widespread in fields in Japan. The similar characteristics of these two pathogens pose a challenge for conventional disease diagnosis. Currently, there are no effective molecular measures for identifying and distinguishing D. destruens and D. batatas. Here, we demonstrate a real-time PCR assay that distinguishes and quantifies D. batatas and D. destruens from co-infected sweet potato. The assay was performed with various simulated DNA combinations of D. batatas and D. destruens ranging from 1:1 to 1:100000. The assay was also used with the ratios of D. batatas: D. destruens: sweet potato DNA ranging from 1:1:1 to 1:1:100000. These assays produced a specific amplification product for each of the pathogens, and quantified the fungal biomass over the entire range tested without detecting false positives. The assay was validated by using infected sweet potato collected from various fields; it showed sufficient sensitivity and specificity to quantify and distinguish D. batatas and D. destruens from these field samples. Thus, our real-time PCR assay would be a useful tool for diagnosis of D. batatas and D. destruens and is expected to provide the foundation for the design of integrated disease management strategies for foot rot disease in sweet potato
Comparison with Magnetic Resonance Three-Dimensional Sequence for Lumbar Nerve Root with Intervertebral Foramen
Study DesignProspective study based on magnetic resonance (MR) imaging of the lumbar spinal root of the intervertebral foramen.PurposeThis study was to compare MR three-dimensional (3D) sequences for the evaluation of the lumbar spinal root of the intervertebral foramen.Overview of LiteratureThe diagnosis of spinal disorders by MR imaging is commonly performed using two-dimensional T1- and T2-weighted images, whereas 3D MR images can be used for acquiring further detailed data using thin slices with multi-planar reconstruction.MethodsOn twenty healthy volunteers, we investigated the contrast-to-noise ratio (CNR) of the lumbar spinal root of the intervertebral foramen with a 3D balanced sequence. The sequences used were the fast imaging employing steady state acquisition and the coherent oscillatory state acquisition for the manipulation of image contrast (COSMIC). COSMIC can be used with or without fat suppression (FS). We compared these sequence to determine the optimized visualization sequence for the lumbar spinal root of the intervertebral foramen.ResultsFor the CNR between the nerve root and the peripheral tissue, these were no significant differences between the sequences at the entry of foramen. There was a significant difference and the highest CNR was seen with COSMIC-FS for the intra- and extra-foramen.ConclusionsIn this study, the findings suggest that the COSMIC-FS sequences should be used for the internal or external foramen for spinal root disorders
Random regression for modeling soybean plant response to irrigation changes using time-series multispectral data
Plant response to drought is an important yield-related trait under abiotic stress, but the method for measuring and modeling plant responses in a time series has not been fully established. The objective of this study was to develop a method to measure and model plant response to irrigation changes using time-series multispectral (MS) data. We evaluated 178 soybean (Glycine max (L.) Merr.) accessions under three irrigation treatments at the Arid Land Research Center, Tottori University, Japan in 2019, 2020 and 2021. The irrigation treatments included W5: watering for 5 d followed by no watering 5 d, W10: watering for 10 d followed by no watering 10 d, D10: no watering for 10 d followed by watering 10 d, and D: no watering. To capture the plant responses to irrigation changes, time-series MS data were collected by unmanned aerial vehicle during the irrigation/non-irrigation switch of each irrigation treatment. We built a random regression model (RRM) for each of combination of treatment by year using the time-series MS data. To test the accuracy of the information captured by RRM, we evaluated the coefficient of variation (CV) of fresh shoot weight of all accessions under a total of nine different drought conditions as an indicator of plant’s stability under drought stresses. We built a genomic prediction model (MTRRM model) using the genetic random regression coefficients of RRM as secondary traits and evaluated the accuracy of each model for predicting CV. In 2020 and 2021,the mean prediction accuracies of MTRRM models built in the changing irrigation treatments (r = 0.44 and 0.49, respectively) were higher than that in the continuous drought treatment (r = 0.34 and 0.44, respectively) in the same year. When the CV was predicted using the MTRRM model across 2020 and 2021 in the changing irrigation treatment, the mean prediction accuracy (r = 0.46) was 42% higher than that of the simple genomic prediction model (r =0.32). The results suggest that this RRM method using the time-series MS data can effectively capture the genetic variation of plant response to drought
- …