Prognostic value of ΔSYNTAX% score in octogenarians undergoing percutaneous coronary intervention

OBJECTIVES To verify whether incomplete revascularisation(IR), quantified using the rSYNTAX(Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score and ΔSYNTAX% score, could predict short-(in-hospital mortality) and long-term outcomes(12-month mortality) in octogenarians undergoing percutaneous coronary intervention(PCI).METHODS & RESULTS A retrospective analysis of 665 consecutive octogenarian patients presenting for PCI to a UK centre was performed. The bas...     

Glucose oversupply increases Δ9-desaturase expression and its metabolites in rat skeletal muscle

AIM/HYPOTHESIS: Previous studies have shown that prolonged glucose infusion causes insulin resistance and triglyceride accumulation in rat skeletal muscle. In this study, we investigated a possible relationship between insulin resistance and the composition of different accumulated lipid fractions in rat skeletal muscle. METHODS: Continuous glucose infusion was carried out in rats for 7 days. Lipids were extracted from skeletal muscle, separated by thin layer chromatography and fatty acid composition of phospholipids, triglycerides, diglycerides, free fatty acids and cholesterol esters fractions was analysed by gas chromatography. Delta9-Desaturase mRNA was measured by real time polymerase chain reaction. The enzyme activity was measured in the microsomal fractions. RESULTS: Prolonged glucose infusion (5 days) increased the relative content of palmitoleic acid (16:1 N7) several-fold (2.3- to 5.8-fold) in four out of five lipid fractions and enhanced oleic acid (18:1 N9) two-fold in three lipid fractions suggesting increased Delta9-desaturase activity while the content of several polyunsaturated fatty acids was reduced. In parallel, Delta9-Desaturase mRNA contents and enzyme activities in skeletal muscle were increased 10-fold, 75-fold, 2.6-fold and 7.7-fold after 2 and 5 days of glucose infusion, respectively. CONCLUSION/INTERPRETATION: Our results suggest that long-term glucose oversupply induces a rapid increase in Delta9-desaturase expression and enzyme activity in skeletal muscle which leads to fast and specific changes in fatty acid metabolism possibly contributing to the insulin resistance in this animal model.     

Revealing the climate of snowball Earth from Δ17O systematics of hydrothermal rocks

The oxygen isotopic composition of hydrothermally altered rocks partly originates from the interacting fluid. We use the triple oxygen isotope composition (¹⁷O/¹⁶O, ¹⁸O/¹⁶O) of Proterozoic rocks to reconstruct the ¹⁸O/¹⁶O ratio of ancient meteoric waters. Some of these waters have originated from snowball Earth glaciers and thus give insight into the climate and hydrology of these critical intervals in Earth history. For a Paleoproterozoic [∼2.3–2.4 gigayears ago (Ga)] snowball Earth, δ¹⁸O = −43 ± 3‰ is estimated for pristine meteoric waters that precipitated at low paleo-latitudes (≤35°N). Today, such low ¹⁸O/¹⁶O values are only observed in central Antarctica, where long distillation trajectories in combination with low condensation temperatures promote extreme ¹⁸O depletion. For a Neoproterozoic (∼0.6–0.7 Ga) snowball Earth, higher meltwater δ¹⁸O estimates of −21 ± 3‰ imply less extreme climate conditions at similar paleo-latitudes (≤35°N). Both estimates are single snapshots of ancient water samples and may not represent peak snowball Earth conditions. We demonstrate how ¹⁷O/¹⁶O measurements provide information beyond traditional ¹⁸O/¹⁶O measurements, even though all fractionation processes are purely mass dependent.Glacial successions deposited near the paleo-equator (≤15°) suggest that the Earth was entirely covered by ice several times during the Precambrian. Such episodes were termed “snowball Earth” climates. Presumably, the concentration of continents at low latitudes enhanced chemical weathering rates and thus removal of CO₂ from the atmosphere (1). Low pCO₂ led to global cooling and formation of polar and continental ice sheets. Once ice caps extended to latitudes below ∼50°, a runaway ice albedo cooling effect occurs (2), global temperatures drop far below zero, and the entire Earth becomes covered with ice (a snowball Earth) (2, 3). At least one “total glaciation” occurred in the Paleoproterozoic era [Makganyene at ∼2.4 gigayears ago (Ga)] (1), and at least two more arose in the Cryogenian (Sturtian at 720 Ma; Marinoan at 635 Ma) (3).The climatic and hydrologic conditions of these critical episodes are poorly understood because classic paleo-thermometers (e.g., marine carbonates) are not viable for snowball Earth states and ancient water samples are missing. The ¹⁸O/¹⁶O ratio of meteoric water (expressed as δ¹⁸O_mw) can serve as a proxy for paleo-temperature if the hydrogeological context is known (4). A few attempts have been made to reconstruct ancient δ¹⁸O_mw (5–8).Calcite cements that precipitated in methane seeps in the Nuccaleena Formation, Australia, probably sample meltwaters from the ∼635 Ma Marinoan snowball Earth with δ¹⁸O ranging around ∼−29‰ (5). The upper carbonate unit of the Lantian Formation in Anhui, South China, probably formed during the younger, ∼580 Ma Gaskiers glaciation within a meltwater-dominated basin. These carbonates appear to be unaltered, hence low precipitation temperatures imply water compositions of δ¹⁸O ≈ −20‰ to −27‰ (6). Barite- and malachite-associated sulfate from a diamictite in Kaiyang, Guizhou, China, reveals meteoric water compositions of δ¹⁸O ≈ −34 ± 10‰, probably representing Marinoan meltwaters (7). Apart from chemical sediments (5, 6) or ancient weathering products (7), it has also been suggested to estimate δ¹⁸O_mw from hydrothermally altered rocks that have interacted with meltwater of meteoric origin (8).Interaction of rocks with meteoric water at hydrothermal conditions (∼350 °C) shifts δ¹⁸O of the rocks (δ¹⁸O_r) toward lower values. Modern examples for such shifts are known from volcanically active regions such as Iceland (9) or Yellowstone. Fossil Phanerozoic and Precambrian hydrothermal systems like the Dabie−Sulu ultra-high-pressure terrain (China) (10) or the Belomorian Belt (Russia) (11) are suggested to have formed similarly to their modern analogs. The lowest δ¹⁸O_r values provide an upper limit for the δ¹⁸O_mw (8). At full equilibration, rocks have a δ¹⁸O_r that is only 2–3‰ higher than the water they interacted with (12), but the degree of equilibration between a rock and a given water is generally unknown, compromising absolute δ¹⁸O_mw estimates (8). Here we present a new approach to reconstruct the absolute δ¹⁸O_mw from measuring not only ¹⁸O/¹⁶O but also the ¹⁷O/¹⁶O ratios of hydrothermal low δ¹⁸O_r Precambrian rocks.     

Non-acid-fastness in Mycobacterium tuberculosis ΔkasB mutant correlates with the cell envelope electron density

The acid-fastness is the most important and the most specific characteristics in mycobacteria, the mechanism of which is not clear but may be attributed to the lipid rich cell wall of this bacterium. While the exact component(s) responsible for this staining method remained unidentified, a Mycobacterium tuberculosis mutant, attenuated strain that produced shorter mycolic acids with defects in trans-cyclopropanation was shown to be acid fast negative. In this study, we examined the ultrastructure of the cell envelope (CE) of the mutant strain ΔkasB (missing a beta-ketoacyl-ACP synthase involved in mycolic acid biosynthesis), the parental CDC1551 (wild type strain) and kasB complemented strain, and compared ultrastructural differences among them with conventional transmission electron microscopy (TEM) and cryo-transmission electron microscopy (CEM). Conventional TEM revealed that there were no detectable differences in the thickness of the cell envelope among three strains (wild-type: 43.35 ± 6.13 nm; ΔkasB: 45.98 ± 11.32 nm; complement: 40.71 ± 6.3 nm). However, CEM data demonstrated that the region between the inner and outer membranes of the mutant strain, which is composed mainly of cell wall anchored mycolic acids (MA), showed a significant decrease in electron density as compared to the wild type and kasB complement strain (567.1 ± 372.7 vs. 301.4 ± 262.1, or vs. 235.2 ± 174.9, p < 0.02 or p < 0.001, respectively). These results suggested that altered MA patterns in the kasB mutant may have affected the packing of the lipid rich layer of the M. tuberculosis cell envelope, resulting in a reduced electron density of this layer as seen by CEM and loss of acid-fastness in light microscopical observation, and we propose a novel model of the cell envelope structure in tubercle bacilli.     

C-terminal unfolding of an amyloidogenic β2-microglobulin fragment: ΔN6β2-microglobulin

Objectives: A β₂-microglobulin (β₂m) fragment that lacks the first six amino acids, i.e., ΔN6β₂-microglobulin (ΔN6β₂m), is an endogenous, proteolytically derived, amyloidogenic fragment of β₂m, the precursor protein in Aβ₂M amyloidosis (dialysis-related amyloidosis). As reports suggest the importance of C-terminal unfolding for the amyloidogenicity of β₂m, in this study we aimed to investigate conformational characteristics of ΔN6β₂m related to amyloidogenicity. We also measured the concentration of an amyloidogenic intermediate of β₂m with C-terminal unfolding (β₂m92-99) in serum samples from 10 patients undergoing hemodialysis (HD).

Methods: We utilized capillary electrophoretic analysis, surface plasmon resonance and enzyme-linked immunosorbent assay.

Results and conclusions: We confirmed the normal core structure of ΔN6β₂m with a commercial monoclonal anti-β₂m antibody. In addition, using the specific monoclonal antibody for the C-terminal peptide, i.e. mAb 92-99, we confirmed unfolding in the C-terminal region of ΔN6β₂m. On the basis of these findings, we established an ELISA to measure β₂m92-99 using ΔN6β₂m as a standard molecule in circulation. However, we did not detect β₂m92-99 in serum from 10 HD patients, despite the absence of uremic inhibitors in the serum.     

The cannabinoid Δ9-tetrahydrocannabivarin (THCV) ameliorates insulin sensitivity in two mouse models of obesity

Background:

Cannabinoid type-1 (CB1) receptor inverse agonists improve type 2 diabetes and dyslipidaemia but were discontinued due to adverse psychiatric effects. Δ⁹-Tetrahydrocannabivarin (THCV) is a neutral CB1 antagonist producing hypophagia and body weight reduction in lean mice. We investigated its effects in dietary-induced (DIO) and genetically (ob/ob) obese mice.

Methods:

We performed two dose-ranging studies in DIO mice; study 1: 0.3, 1, 2.5, 5 and 12.5 mg kg⁻¹, oral twice daily for 30 days and study 2: 0.1, 0.5, 2.5 and 12.5 mg kg⁻¹, oral, once daily for 45 days. One pilot (study 3: 0.3 and 3 mg kg⁻¹, oral, once daily) and one full dose-ranging (study 4: 0.1, 0.5, 2.5 and 12.5 mg kg⁻¹, oral, once daily) studies in ob/ob mice for 30 days. The CB1 inverse agonist, AM251, oral, 10 mg kg⁻¹ once daily or 5 mg kg⁻¹ twice daily was used as the positive control. Cumulative food and water intake, body weight gain, energy expenditure, glucose and insulin levels (fasting or during oral glucose tolerance tests), plasma high-density lipoprotein and total cholesterol, and liver triglycerides were measured. HL-5 hepatocytes or C₂C₁₂ myotubes made insulin-resistant with chronic insulin or palmitic acid were treated with 0, 1, 3 and 10 μℳ THCV or AM251.

Results:

THCV did not significantly affect food intake or body weight gain in any of the studies, but produced an early and transient increase in energy expenditure. It dose-dependently reduced glucose intolerance in ob/ob mice and improved glucose tolerance and increased insulin sensitivity in DIO mice, without consistently affecting plasma lipids. THCV also restored insulin signalling in insulin-resistant hepatocytes and myotubes.

Conclusions:

THCV is a new potential treatment against obesity-associated glucose intolerance with pharmacology different from that of CB1 inverse agonists/antagonists.     

Differing time courses between Δlactate and mitochondrial respiration during coronary occlusion and after reperfusion in canine hearts

Summary The present study was designed to clarify whether or not a difference between arterial and venous lactate (lactate) levels is useful for evaluation of mitochondrial function in ischemia-reperfused myocardium. In the first experiment, 12 dogs were divided into 2 groups: 10-min occlusion of the left anterior descending coronary artery (LAD) followed by 10-min reperfusion, or 30-min occlusion followed by 40-min reperfusion, were performed. The lactate levels in the femoral artery and the great cardiac vein were measured enzymatically. Lactate was reversed immediately after occlusion. Ten min and 20 min were required for the recovery of lactate in the 10-min-occlusion with 10-min-reperfusion, and 30-min-occlusion with 40-min-reperfusion groups, respectively. In the second experiment, 36 dogs were divided into 6 groups: 10-min occlusion of LAD; 10-min occlusion with 10-min reperfusion; 30-min occlusion; and 30-min occlusion with 10-, 20-, or 40-min reperfusion were performed. Mitochondria from normal and occluded or reperfused areas were prepared, and the respiratory function of the mitochondria was measured polarographically. No significant decreases in the mitochondrial function were observed in the 10-min-occlusion, and 10-min-occlusion with 10-min-reperfusion groups. On the other hand, respiratory function of mitochondria was impaired by 30-min occlusion and was not improved by 10- or 20-min reperfusion. Significant recovery in the mitochondrial function was observed after 40-min reperfusion. That is, differing recovery time courses between lactate and the mitochondrial function were observed.     

Rosiglitazone increases fatty acid Δ9-desaturation and decreases elongase activity index in human skeletal muscle in vivo

The ratio of unsaturated to saturated long-chain fatty acids (LC-FAs) in skeletal muscle has been associated with insulin resistance. Some animal data suggest a modulatory effect of peroxisome proliferator receptor γ (PPARγ) stimulation on stearoyl-CoA desaturase 1 (SCD1) and LC-FA composition in skeletal muscle, but human data are rare. We here investigate whether treatment with a PPARγ agonist affects myocellular SCD1 expression and modulates the intramyocellular fatty acid profile in individuals with impaired glucose tolerance. Muscle biopsies and hyperinsulinemic-euglycemic clamps were performed in 7 men before and after 8 weeks of rosiglitazone treatment. Intramyocellular saturated, monounsaturated, and polyunsaturated intramuscular fatty acid profiles were measured by gas chromatography. Effects on SCD1 messenger RNA expression were analyzed in C2C12 cells and in human biopsies before and after rosiglitazone treatment. As expected, treatment with the PPARγ activator rosiglitazone improved insulin sensitivity in humans. Myocellular SCD1 messenger RNA expression was increased in human biopsies and C2C12 cells. Although the total content of myocellular LC-FA was unchanged, a relative shift from saturated LC-FAs to unsaturated LC-FAs was observed in human biopsies. Particularly, the amount of stearate was reduced, whereas the amounts of palmitoleate as well as oleate and vaccenate were increased, after rosiglitazone therapy. These changes resulted in an increased fatty acid Δ9-desaturation index (16:1/16:0 and 18:1/18:0) in skeletal muscle and a decreased elongase activity index (18:0/16:0). The PPARγ associated phenotypes may be partially explained by an increased Δ9-desaturation and a decreased elongase activity of skeletal muscle.     

Structural dynamics of the ΔE22 (Osaka) familial Alzheimer’s disease-linked amyloid β-protein

A familial form of Alzheimer disease recently was described in a kindred in Osaka, Japan. This kindred possesses an amyloid β-protein (Aβ) precursor mutation within the Aβ coding region that results in the deletion of Glu22 (ΔE22). We report here results of studies of [ΔE22]Aβ40 and [ΔE22]Aβ42 that sought to elucidate the conformational dynamics, oligomerization behavior, fibril formation kinetics, fibril morphology, and fibril stability of these mutant peptides. Both [ΔE22]Aβ peptides had extraordinary β-sheet formation propensities. The [ΔE22]Aβ40 mutant formed β-sheet secondary structure elements ≈400-fold faster. Studies of β-sheet stability in the presence of fluorinated alcohol cosolvents or high pH revealed that the ΔE22 mutation substantially increased stability, producing a rank order of [ΔE22]Aβ42 ? Aβ42 > [ΔE22]Aβ40 > Aβ40. The mutation facilitated formation of oligomers by [ΔE22]Aβ42 (dodecamers and octadecamers) that were not observed with Aβ42. Both Aβ40 and Aβ42 peptides formed nebulous globular and small string-like structures immediately upon solvation from lyophilizates, whereas short protofibrillar and fibrillar structures were evident immediately in the ΔE22 samples. Determination of the critical concentration for fibril formation for the [ΔE22]Aβ peptides showed it to be ≈1/2 that of the wild type homologues, demonstrating that the mutations causes a modest increase in fibril stability. The magnitude of this increase, when considered in the context of the extraordinary increase in β-sheet propensity for the ΔE22 peptides, suggests that the primary biophysical effect of the mutation is to accelerate conformational changes in the peptide monomer that facilitate oligomerization and higher-order assembly.     

Human pyrroline-5-carboxylate reductase (PYCR1) acts on Δ1-piperideine-6-carboxylate generating L-pipecolic acid

We have conducted biochemical studies with commercial available pyrroline-5-carboxylate (P5C) reductase (PYCR1) to investigate whether this enzyme plays a role in L-lysine degradation. Our recent studies with antiquitin/ALDH7A1 deficient fibroblasts revealed an alternative genesis of L-pipecolic acid, and we then hypothesized that PYCR1 was responsible for the conversion of Δ¹-piperideine-6-carboxylate (P6C) into pipecolic acid. We here present evidence that PYCR1 is indeed able to produce L-pipecolic acid from P6C preparations, and the observed K _m for this conversion is of the same magnitude as the K _m described for the conversion of P5C to L-proline by PYCR1. Urine samples from antiquitin deficient individuals, who accumulate P6C, were also incubated with PYCR1 which resulted in a marked decrease of P6C and a huge increase of L-pipecolic acid as measured by LC-MS/MS, confirming that indeed PYCR1 generates L-pipecolic acid from P6C.     

Chemokine receptor 5 Δ32 polymorphism and systemic lupus erythematosus,vasculitis, and primary Sjogren’s syndrome

Objective

The aim of this study was to determine whether the functional chemokine receptor 5 delta32 (CCR5-Δ32) polymorphism is associated with susceptibility to systemic lupus erythematosus (SLE), vasculitis, and primary Sjogren’s syndrome (pSS).

Results

A total of 12 studies were analyzed, including 5 on SLE, 5 on vasculitis, and 2 on pSS, encompassing 1881 patients and 2391 controls. Meta-analysis indicated no association between SLE and the CCR5-Δ32 allele (OR 0.842, 95?% CI 0.793–1.804, p?=?0.657), and no association between the CCR5-Δ32 allele and SLE in Europeans (OR 0.647, 95?% CI 0.306–1.368, p?=?0.255). Meta-analysis of the CCR5-Δ32 allele and the Δ32Δ32?+?Δ32 W genotype showed no association with lupus nephritis (LN; OR 1.771, 95?% CI 0.475–6.595, p?=?0.395; OR 2.192, 95?% CI 0.182–26.42, p?=?0.537, respectively). In addition, meta-analysis revealed no association between the CCR5-Δ32 allele and vasculitis in all study subjects and in Europeans (OR 1.241, 95?% CI 0.951–1.620, p?=?0.111; OR 1.359, 95?% CI 0.803–2.303, p?=?0.254, respectively). However, the overall OR for the CCR5-Δ32 allele was significantly higher in Kawasaki disease (KD; OR 1.746, 95?% CI 1.003–2.955, p?=?0.038) and the meta-analysis of the Δ32Δ32?+?Δ32 W genotype showed a trend indicating an association with KD (OR 1.683, 95?% CI 0.921–3.077, p?=?0.091). No association was found between the CCR5-Δ32 polymorphism and pSS.

Conclusion

This meta-analysis demonstrates that the CCR5-Δ32 polymorphism is associated with KD, but does not facilitate susceptibility to SLE, LN, or pSS.     

Visualization of rodent brain tumor angiogenesis and effects of antiangiogenic treatment using 3D ΔR2-μMRA

Understanding of structural and functional characteristics of the vascular microenvironment in gliomas and the impact of antiangiogenic treatments is essential for developing better therapeutic strategies. Although a number of methods exist in which this process can be studied experimentally, no single noninvasive test has the capacity to provide information concerning both microvascular function and morphology. The purpose of present study is to demonstrate the feasibility of using a novel three-dimensional ΔR₂-based microscopic magnetic resonance angiography (3D ΔR₂-μMRA) technique for longitudinal imaging of tumor angiogenesis and monitoring the effects of antiangiogenic treatment in rodent brain tumor models. Using 3D ΔR₂-μMRA, a generally consistent early pattern of vascular development in gliomas was revealed, in which a single feeding vessel was visualized first (arteriogenesis), followed by sprouting angiogenesis. Considerable variability of the tumor-associated vasculature was then noted at later stages of tumor evolution. ΔR₂-μMRA revealed that anti-vascular endothelial growth factor treatment induced a rapid and significant alteration of the intratumoral angiogenic phenotype. In summary, 3D ΔR₂-μMRA enables high-resolution visualization of tumor-associated vessels while simultaneously providing functional information on the tumor microvasculature. It can serve as a useful tool for monitoring both the temporal evolution of tumor angiogenesis and the impact of antiangiogenic therapies.