Durability of protective effect of dulaglutide on pancreatic ß-cells in diabetic mice: GLP-1 receptor expression is not reduced despite long-term dulaglutide exposure.

AIMS: It is well-known that chronic exposure to large amounts of ligand leads to downregulation of its receptor. It is not known, however, whether a GLP-1R agonist downregulates its receptor. For this reason, our study examined whether GLP-1R expression is reduced after long-term exposure to dulaglutide (Dula) in non-diabetic and diabetic mice. METHODS: Seven-week-old male db/db and db/m mice were given either Dula (0.6mg/kg×2/week) or a control vehicle (CTL) for 17 weeks. Various metabolic parameters, such as glucose-stimulated insulin secretion (GSIS), insulin and TG content in islets, were evaluated after the intervention. ß-cell-related gene expression was also analyzed by real-time RT-PCR. RESULTS: In db/m mice, GLP-1R expression in ß-cells did not decrease, not even after long-term administration of Dula, compared with control mice, while GLP-1R expression in 24-week-old db/db mice treated with Dula was augmented, rather than downregulated, compared with 24-week-old CTL db/db mice. This was probably due to improved glycaemic control. In db/db mice treated with Dula, food intake and blood glucose levels were significantly decreased up to 24 weeks of age compared with CTL db/db mice, and their expression levels of various ß-cell-related genes, insulin content and GSIS were also enhanced. In contrast, oxidative and endoplasmic reticulum stress, inflammation, fibrosis and apoptosis were suppressed with Dula treatment. CONCLUSION: Dula exerts beneficial effects on glycaemic control and has long-lasting protective effects on pancreatic ß-cells. GLP-1R expression levels were not reduced at all in non-diabetic as well as diabetic mice despite long-term dulaglutide exposure.

Intermetallic: A Pseudoelement for Catalysis.

A clear correlation between electronic structure and CO2 selectivity for steam reforming of methanol (SRM) was obtained with PdZn, PtZn, NiZn, and PdCd intermetallics on the basis of experiments and calculations. In order to rule out the effects of oxide supports, the intermetallic powders were simply prepared by alloying in an arc furnace followed by crushing in a mortar. PdZn and PdCd exhibit valence electronic densities of states similar to that of Cu and significant chemical shifts (larger than 1 eV) of Pd 3d states with respect to pure Pd, as verified by high-resolution hard X-ray photoelectron spectroscopy (HXPS) measurements and density functional theory (DFT) calculations. Consequently, they show the similar high selectivity of CO2 for the SRM reaction. However, this is not the case for PtZn and NiZn because of the slight differences in their valence electronic structures from that of PdZn. The interval between the Fermi level and the top of the d band is closely related to the selectivity of CO2 for the SRM: the larger the interval is, the higher is the selectivity of CO2. According to DFT calculations for bulk PdZn performed by Chen et al. ( Phys. Rev. B 2003 , 68 , 075417 ), the (111) and (100) surfaces exposing Zn and Pd in an equimolar ratio are more stable than the (001) or (110) surfaces terminated by alternative Zn or Pd layers. First-principles slab calculations for PdZn, PtZn, and NiZn show that bond breaking on the surface leads to a reduction in the d bandwidth but that the d band for stable (111) or (100) surfaces remains essentially unchanged from that of the bulk. It is intriguing that PdZn and PdCd do not contain Cu but show similar valence electronic structure and catalytic selectivity, and hence, a concept is proposed where PdZn and PdCd are regarded as pseudoelements of Cu. The basis of this concept is like electronic structure, like catalysis, which has been demonstrated by experiments and calculations. This is a logical way to enable us to look for new catalysts in which precious metals are partially or completely replaced by base metals. We do not expect that this concept can be applied to all catalytic reactions, but this approach is one of most promising ways to derive a better understanding of the origin of catalytic mechanisms and eventually allow us to design useful catalysts intentionally in the future. This Account reviews the authors' published works on this topic.

Centripetal Propagation of Vasoconstriction at the Time of Headache Resolution in Patients with Reversible Cerebral Vasoconstriction Syndrome.

BACKGROUND AND PURPOSE: Reversible cerebral vasoconstriction syndrome is characterized by thunderclap headache and diffuse segmental vasoconstriction that resolves spontaneously within 3 months. Previous reports have proposed that vasoconstriction first involves small distal arteries and then progresses toward major vessels at the time of thunderclap headache remission. The purpose of this study was to confirm centripetal propagation of vasoconstriction on MRA at the time of thunderclap headache remission compared with MRA at the time of reversible cerebral vasoconstriction syndrome onset. MATERIALS AND METHODS: Of the 39 patients diagnosed with reversible cerebral vasoconstriction syndrome at our hospital during the study period, participants comprised the 16 patients who underwent MR imaging, including MRA, within 72 hours of reversible cerebral vasoconstriction syndrome onset (initial MRA) and within 48 hours of thunderclap headache remission. RESULTS: In 14 of the 16 patients (87.5%), centripetal propagation of vasoconstriction occurred from the initial MRA to remission of thunderclap headache, with typical segmental vasoconstriction of major vessels. These mainly involved the M1 portion of the MCA (10 cases), P1 portion of the posterior cerebral artery (10 cases), and A1 portion of the anterior cerebral artery (5 cases). CONCLUSIONS: This study found evidence of centripetal propagation of vasoconstriction on MRA obtained at the time of thunderclap headache remission, compared with MRA obtained at the time of reversible cerebral vasoconstriction syndrome onset. If clinicians remain unsure of the diagnosis during early-stage reversible cerebral vasoconstriction syndrome, this time point represents the best opportunity to diagnose reversible cerebral vasoconstriction syndrome with confidence.

Neuroradiologic Diagnosis of Minor Leak prior to Major SAH: Diagnosis by T1-FLAIR Mismatch.

BACKGROUND AND PURPOSE: In major SAH, the only method to diagnose a preceding minor leak is to ascertain the presence of a warning headache by interview; however, poor clinical condition and recall bias can cause inaccuracy. We devised a neuroradiologic method to diagnose previous minor leak in patients with SAH and attempted to determine whether warning (sentinel) headaches were associated with minor leaks before major SAH. MATERIALS AND METHODS: We retrospectively evaluated 127 patients who were admitted with SAH within 48 hours of ictus. Previous minor leak before major SAH was defined as T1WI-detected clearly bright hyperintense subarachnoid blood accompanied by SAH blood on FLAIR images that was distributed over a larger area than bright hyperintense subarachnoid blood on T1WI (T1-FLAIR mismatch). RESULTS: The incidence of warning headache before SAH was 11.0% (14 of 127 patients, determined by interview). The incidence of T1-FLAIR mismatch (neuroradiologic diagnosis of minor leak before major SAH) was 33.9% (43 of 127 patients). Of the 14 patients with warning headache, 13 had a minor leak diagnosed by T1-FLAIR mismatch at the time of admission. Variables identified by multivariate analysis as significantly associated with minor leak diagnosed by T1-FLAIR mismatch included 80 years of age or older, rebleeding after admission, intracerebral hemorrhage on CT, and mRS scores of 3-6. CONCLUSIONS: We conclude that warning headaches diagnosed by interview are not a product of recall bias but are the result of actual leaks from aneurysms.

Randomized clinical trial of adjuvant chemotherapy with S-1 versus gemcitabine after pancreatic cancer resection.

BACKGROUND: Randomized studies of adjuvant chemotherapy using gemcitabine suggest a survival benefit after resection of pancreatic cancer. S-1 has also been shown to prolong survival in patients with unresectable pancreatic cancer. This study compared the effects of adjuvant chemotherapy with S-1 or gemcitabine after resection of pancreatic cancer in a randomized trial. METHODS: Patients who had undergone resection of pancreatic cancer were registered in this randomized clinical trial. The primary endpoint was disease-free survival (DFS). Expression levels of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) mRNAs in cancer tissues were measured as indicators of fluoropyrimidine sensitivity. RESULTS: Of 57 patients registered, 29 were allocated to the S-1 group and 28 to gemcitabine. DFS tended to be better with S-1 (median 14·6 (90 per cent c.i. 8·8 to 28·4) months versus 10·5 (7·0 to 28·4) months in the gemcitabine group; P = 0·188), with a similar pattern for overall survival: 21·5 (95 per cent c.i. 14·4 to 42·3) and 18·0 (13·3 to 42·8) months respectively (P = 0·293). When patients were divided into subgroups based on high or low DPD and TS expression, those with a DPD level below the median of 0·88 or a TS level of at least 2·00 had a significant prolongation of DFS after S-1 treatment compared with gemcitabine (P = 0·008 and P = 0·035 respectively). CONCLUSION: Overall, S-1 did not improve DFS compared with gemcitabine after pancreatic cancer resection, but there seemed to be a DFS advantage in patients with low expression of DPD or high expression of TS. Reference number: UMIN000009118 (http://www.umin.ac.jp/ctr/).

Crystalline and quasicrystalline allotropes of Pb formed on the fivefold surface of icosahedral Ag-In-Yb.

Crystalline and quasicrystalline allotropes of Pb are formed by evaporation on the fivefold surface of the icosahedral (i) Ag-In-Yb quasicrystal under ultra-high vacuum. Lead grows in three dimensional quasicrystalline order and subsequently forms fivefold-twinned islands with the fcc(111) surface orientation atop of the quasicrystalline Pb. The islands exhibit specific heights (magic heights), possibly due to the confinement of electrons in the islands. We also study the adsorption behavior of C60 on the two allotropes of Pb. Scanning tunneling microcopy reveals that a high corrugation of the quasicrystalline Pb limits the diffusion of the C60 molecules and thus produces a disordered film, similar to adsorption behavior of the same molecules on the clean substrate surface. However, the sticking coefficient of C60 molecules atop the Pb islands approaches zero, regardless of the overall C60 coverage.

Structure of the twofold surface of the icosahedral Ag-In-Yb quasicrystal.

The structure of the twofold surface of the icosahedral (i-)Ag-In-Yb quasicrystal has been investigated using low energy electron diffraction (LEED) and scanning tunneling microscopy (STM). The LEED confirms that the surface exhibits quasicrystalline long range order with the twofold rotational symmetry expected from the bulk. STM images reveal a step-terrace structure with terrace size comparable to that of the other high symmetry surfaces of the same quasicrystal. The distribution of step heights and high resolution STM images of terraces suggest that the surface terminates at bulk planes that intersect the center of rhombic triacontahedral clusters, the building blocks of the system, as in the case of the threefold and fivefold surfaces of the system. These planes are rich in Yb and In. No facets are observed on the surface, suggesting that the twofold surface is as stable as the other high symmetry surfaces.

Construction of novel immune-related signature for prediction of pathological complete response to neoadjuvant chemotherapy in human breast cancer.

BACKGROUND: The aim of this study was to construct a novel prediction model for the pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) using immune-related gene expression data. PATIENTS AND METHODS: DNA microarray data were used to perform a gene expression analysis of tumor samples obtained before NAC from 117 primary breast cancer patients. The samples were randomly divided into the training (n = 58) and the internal validation (n = 59) sets that were used to construct the prediction model for pCR. The model was further validated using an external validation set consisting of 901 patients treated with NAC from six public datasets. RESULTS: The training set was used to construct an immune-related 23-gene signature for NAC (IRSN-23) that is capable of classifying the patients as either genomically predicted responders (Gp-R) or non-responders (Gp-NR). IRSN-23 was first validated using an internal validation set, and the results showed that the pCR rate for Gp-R was significantly higher than that obtained for Gp-NR (38 versus 0%, P = 1.04E-04). The model was then tested using an external validation set, and this analysis showed that the pCR rate for Gp-R was also significantly higher (40 versus 11%, P = 4.98E-23). IRSN-23 predicted pCR regardless of the intrinsic subtypes (PAM50) and chemotherapeutic regimens, and a multivariate analysis showed that IRSN-23 was the most important predictor of pCR (odds ratio = 4.6; 95% confidence interval = 2.7-7.7; P = 8.25E-09). CONCLUSION: The novel prediction model (IRSN-23) constructed with immune-related genes can predict pCR independently of the intrinsic subtypes and chemotherapeutic regimens.

Templated three-dimensional growth of quasicrystalline lead.

Quasicrystals, materials with aperiodic long-range order, have been found in intermetallics, soft materials such as colloids and supermolecules, and also in two-dimensional monolayer films. Here we present the first example of three-dimensional growth of a single-element quasicrystalline film. Using a hitherto unexplored template, the icosahedral Ag-In-Yb quasicrystal, and various experimental techniques combined with theoretical calculations of adsorption energies, we find that lead atoms deposited on the surface occupy the positions of atoms in the rhombic triacontahedral cluster, the building block of the substrate, and thus grow in layers with different heights and adsorption energies. We show that the adlayer-adlayer interaction is crucial for stabilizing this epitaxial quasicrystalline structure. The finding opens an avenue for further investigation of the impact of the aperiodic atomic order over periodic order on the physical and chemical properties of materials.

Vildagliptin preserves the mass and function of pancreatic ß cells via the developmental regulation and suppression of oxidative and endoplasmic reticulum stress in a mouse model of diabetes.

AIM: We investigated the molecular mechanisms by which vildagliptin preserved pancreatic ß cell mass and function. METHODS: Morphological, biochemical and gene expression profiles of the pancreatic islets were investigated in male KK-A(y) -TaJcl(KK-A(y) ) and C57BL/6JJcl (B6) mice aged 8 weeks which received either vildagliptin or a vehicle for 4 weeks. RESULTS: Body weight, food intake, fasting blood glucose, plasma insulin and active glucagon-like peptide-1 were unchanged with vildagliptin treatment in both mice. In KK-A(y) mice treated with vildagliptin, increased plasma triglyceride (TG) level and islet TG content were decreased, insulin sensitivity significantly improved, and the glucose tolerance ameliorated with increases in plasma insulin levels. Furthermore, vildagliptin increased glucose-stimulated insulin secretion, islet insulin content and pancreatic ß cell mass in both strains. By vildagliptin, the expression of genes involved in cell differentiation/proliferation was upregulated in both strains, those related to apoptosis, endoplasmic reticulum stress and lipid synthesis was decreased and those related to anti-apoptosis and anti-oxidative stress was upregulated, in KK-A(y) mice. The morphological results were consistent with the gene expression profiles. CONCLUSION: Vildagliptin increases ß cell mass by not only directly affecting cell kinetics but also by indirectly reducing cell apoptosis, oxidative stress and endoplasmic reticulum stress in diabetic mice.

Stimulation of adult resident cardiac progenitor cells by durable myocardial expression of thymosin beta 4 with ultrasound-targeted microbubble delivery.

It has been proposed that thymosin beta 4 (TB4)-protein delivery stimulates differentiation of resident adult WT1-positive cardiac progenitor cells, but with very low efficiency. We determined whether gene therapy with human TB4 stimulates proliferation of resident adult cardiac progenitor cells in normal rat heart. Ultrasound-targeted microbubble destruction (UTMD) was used to deliver the human TB4 gene under a piggybac transposon plasmid to normal rat heart. The rat hearts were assayed by quantitative reverse transcription-PCR and immunohistology with a confocal microscope at 1, 2, 3, 4 and 12 weeks after UTMD. Exogenous TB4 stimulation resulted in the presence of WT1-positive cardiac progenitor cells from epicardium to endocardium. TB4 stimulated angiogenesis and arteriogenesis. One month after TB4 gene therapy by UTMD, the percentage of NKX2.5-positive cardiomyocytes was 5.5±1.0% and NKX2.5 mRNA was 24-fold higher than in the control groups (P<0.001). Similar results were found for ISL-1, BrDu, Ki-67, PHH3 and aurora B (P<0.001). Cardiac-specific delivery of exogenous human TB4 gene efficiently stimulates proliferation and differentiation of resident WT1-positive adult cardiac progenitor cells into three intact cardiac cell lineages-vascular endothelial cells, coronary artery smooth muscle cells and cardiac muscle cells in normal adult rat heart.

The atomic structure of the threefold surface of the icosahedral Ag-In-Yb quasicrystal.

We report a study of the atomic structure of the threefold icosahedral (i-)Ag-In-Yb quasicrystal surface using scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). The LEED confirms that the surface exhibits quasicrystalline long-range order with the threefold symmetry expected from the bulk. The STM reveals large atomically flat terraces separated by steps of different heights. A comparison of atomically resolved STM images for the terraces and the step-height distribution with the bulk structure of isostructural i-Cd-Yb shows that the terraces are formed at bulk planes intersecting the centers of the rhombic triacontahedral clusters that make up the bulk structure of the system. However, the stability of particular terraces may be influenced by the density of atoms in the interstices (glue atoms that bind the clusters) in the terraces and also by the chemical environment in the underlying atomic plane. The surface exhibits screw dislocations, which is explained in terms of a continuous atomic density along the threefold axis.

High-mobility group box 1 expressions in hypoxia-induced damaged mouse islets.

INTRODUCTION: Discovering a new, accurate, and useful damage marker for isolated islets is critical for avoiding the transplantation of nontherapeutic preparations. Recently, we have reported that islets that contained uniquely high levels of high-mobility group box 1 (HMGB1) protein and cytokine induced damaged islets released HMGB1 in a mouse model. Islets are frequently exposed to hypoxic conditions during organ procurement, organ transportation, islet isolation, and islet storage before transplantation. In the present study, we analyzed HMGB1 expressions in hypoxia-induced damaged mouse islets. METHODS: Damaged mouse islets were generated by hypoxic conditions (1% O2, 5% CO(2), and 94% N(2)). HMGB1 expressions and production levels were assessed by quantitative real-time polymerase chain reaction (PCR), Western blotting, and enzyme-linked immunosorbent assay (ELISA) studies. In vivo islet function was analyzed using transplantation assay using streptozotocin-induced diabetic mice. RESULTS: HMGB1 was mainly stained in the nucleus in the intact islets; however, HMGB1 was present in not only the nucleus, but also the cytoplasm in hypoxia-induced damaged islets. HMGB1 messenger RNA (mRNA) levels were up-regulated in the hypoxia-induced damaged islets, suggesting that HMGB1 was intentionally generated during hypoxia. HMGB1 protein levels in the islets were gradually decreased with time under hypoxic conditions. The amount of released HMGB1 levels and the amount of released HMGB1 levels per hour were significantly increased in damaged (noncurable) islets. CONCLUSIONS: When islets were damaged by hypoxic condition, HMGB1 was synthesized and released from hypoxia-induced damaged islets. The amount of released HMGB1 and/or the amount of released HMGB1 per hour might be a useful marker for detecting damaged islets and might be used for islet potency assay.

An effective method to release human islets from surrounding acinar cells with agitation in high osmolality solution.

INTRODUCTION: Islet purification is mainly performed by the density gradient method. However, purification of the embedded islets that are surrounded by exocrine tissue should be difficult, because their density is similar to exocrine tissue. In this study, we performed chart review to assess the relationship between the ratio of embedded islets and efficacy of purification. Then, we tested several conditions of a new method to free the islets from surrounded exocrine tissues using high osmolality solution with gentle agitation. MATERIALS AND METHODS: First, we performed chart review of our human islet isolation. Second, embedded islet-enriched human islet fractions (embedded islets >50%) were suspended in University of Wisconsin (UW) solution (UW group, 320 mOsm/kg/H(2)0) or osmolality-adjusted UW solution (400, 500, and 600 mOsm/kg/H(2)0; 400 group, 500 group, and 600 group, respectively). Each tube was gently shaken at 4°C. The tissue samples were taken before shaking and after 15, 30, and 60 minutes. Islet yield, percentage of embedded islets, and viabilities were assessed. RESULTS: The chart review revealed that high ratio of embedded islets deteriorated the efficacy of islet purification. The islet yield in all groups except for the 600 group did not change at 15 minutes, but it decreased in all groups at 60 minutes. The average percentage of embedded islets before shaking was 62.6%. Although percentage of embedded islets were decreasing in all groups, it was < 20% at 15 minutes in the 500 and 600 groups whereas it was >44% in the UW group, which indicated that higher osmolality would have a greater effect. Viability was >95% in all groups at 30 minutes. CONCLUSIONS: The embedded islets deteriorated the efficacy of islet purification. Gentle agitation of embedded islets in high osmolality (500 mOsm/kg/H(2)O, 15 minutes) could release islets from surrounded exocrine tissue.

Usefulness of the secretory unit of islet transplant objects (SUITO) index for evaluation of clinical autologous islet transplantation.

BACKGROUND: Assessing the engrafted islet mass is important in evaluating the efficacy of islet transplantation. We previously demonstrated that the average secretory unit of islet transplant objects (SUITO) index within 1 month of allogeneic islet transplantation was an excellent predictor of insulin independence. However, the usefulness of the SUITO index for evaluating autologous islet transplantation has not been explored. The purpose of the present study was to assess the relationship between the SUITO index and clinical outcomes after total pancreatectomy followed by autologous islet transplantation. METHODS: We performed 27 total pancreatectomies followed by autologous islet transplantation from October 2006 to January 2011. Cases were divided into an insulin-independent group (IIG; n = 12) and an insulin-dependent group (lDG; n = 15). The SUITO index was calculated by the formula [fasting C-peptide (ng/mL)/fasting glucose (mg/dL) -63] × 1,500. The average SUITO index within the first month of transplantation except for days 0, 1, and 2, maximum SUITO index, and most recent SUITO index were calculated in each case, and values were compared between the IIG and the IDG. RESULTS: The average SUITO index within 1 month was significantly higher in the IIG than in the IDG (24.6 ± 3.4 vs 14.9 ± 2.0, respectively; P < .02). The maximum SUITO indices were 45.7 ± 7.7 in the IIG and 30.1 ± 8.1 in the IDG (not significant), and the recent SUITO indices were 36.9 ± 6.7 in the IIG and 22.8 ± 6.1 in the IDG (not significant). CONCLUSIONS: The average SUITO index within 1 month was an excellent predictor of insulin independence after total pancreatectomy followed by autologous islet transplantation.