Prevalence and Prognostic Value of Mesenteric Artery Stenosis in Patients Undergoing Transcatheter Aortic Valve Implantation

Introduction

Data regarding the prevalence of mesenteric artery stenosis in patients undergoing transcatheter aortic valve implantation (TAVI) are scarce. Whether patients with high-risk features for acute mesenteric ischemia (AMesI) have a worse prognosis compared with those without high-risk features is unknown. We aimed to address these questions.

Methods

We included 361 patients who underwent TAVI between 2015 and 2019. Using pre-TAVI computed tomography exams, the number of stenosed arteries in each patient and the degree of stenosis for the coeliac trunk (CTr), SMA and inferior mesenteric artery (IMA) were analyzed. High-risk features for AMesI were defined as the presence of ≥2 arteries presenting with ≥50% stenosis. Patient demographic and echocardiographic data were collected. Endpoints included 30-day all-cause mortality, mortality and morbidity related to mesenteric ischemia.

Results

22.7% of patients had no arterial stenosis, while 59.3% had 1 or 2 stenosed arteries, and 18.0% presented stenoses in 3 arteries. Prevalence of significant stenosis (≥50%) in CTr, SMA, and IMA were respectively 11.9, 5.5, 10.8%. Twenty patients at high-risk for AMesI were identified: they had significantly higher all-cause mortality (15.0 vs. 1.2%, p < 0.001) and higher mortality related to AMesI (5.0 vs. 0.3%, p = 0.004), compared with non-high-risk patients.

Conclusions

Patients at high-risk for AMesI presented with significantly higher 30-day all-cause mortality and mortality related to AMesI following TAVI. Mesenteric revascularization before TAVI interventions may be beneficial in these patients. Prospective studies are needed to clarify these questions.

Regioselective chitosan end-group activation: the triskelion approach

Non-reactive chitosan extremities are regioselectively activated with a trivalent linker, called triskelion, allowing subsequent end-group functionalization with any thiol-reactive species.

Dietary intake of subjects with diabetes is inadequate in Switzerland: the CoLaus study

PURPOSE

To characterize the dietary intake of subjects aged 40-80 years according to self-reported diabetes and presence of an anti-diabetic diet.

METHODS

Cross-sectional study conducted between 2009 and 2012 on 4289 participants (2274 women) living in Lausanne.

RESULTS

Of the 299 (7 %) participants with self-reported diabetes, only 151 (51 %) reported an anti-diabetic diet. Compared to participants not reporting diabetes, participants with self-reported diabetes (with or without a diet) had a higher consumption of artificial sweeteners (0.3 ± 0.7 vs. 0.4 ± 0.8 and 0.8 ± 1.0 times/day) and a lower consumption of honey/jam (mean ± standard deviation: 0.5 ± 0.5 vs. 0.4 ± 0.4 and 0.4 ± 0.4 times/day) or sugar (0.6 ± 0.9 vs. 0.4 ± 0.7 and 0.2 ± 0.5 times/day) for participants not reporting diabetes, participants with self-reported diabetes not on a diet and on a diet, respectively. Compared to participants not on a diet, participants on a diet had a higher consumption of vegetables (1.8 ± 1.3 vs. 1.4 ± 1.0 portions/day), while no differences were found regarding all other food groups and nutrients. Participants with self-reported diabetes on a diet had a higher consumption of meat (5.6 ± 3.6 vs. 4.8 ± 2.9 portions/week) and a lower consumption of simple carbohydrates (21.0 ± 7.9 vs. 23.5 ± 8.4 % total energy intake) than participants not reporting diabetes.

CONCLUSION

People with diabetes eat less simple carbohydrates, but do not comply with current advice on fish, nuts, fruits and vegetables. Improvement of the dietary intake in persons with diabetes in Switzerland is needed.

Lost in translation: dietary management of cardiovascular risk factors is seldom implemented

OBJECTIVE

To assess dietary management of cardiovascular risk factors (CVRFs) in the general population.

METHOD

Cross-sectional study conducted between 2009 and 2012 on 4811 participants (2567 women, 58±11years) living in Lausanne, Switzerland.

RESULTS

Sixteen percent of participants diagnosed with overweight/obesity reported a slimming diet. Slimming diet was associated with diagnosis of hypertension: Odds ratio and (95% confidence interval): 0.61 (0.40-0.93); older age [0.84 (0.58-1.21), 0.79 (0.53-1.18) and 0.47 (0.27-0.81) for [50-60[, [60-70[ and [70+ years, respectively]; female gender [1.84 (1.36-2.48)] and diagnosis of diabetes [2.16 (1.13-4.12)]. Only 8% of participants diagnosed with hypertension reported a low-salt diet. Low-salt diet was associated with antihypertensive drug treatment [2.17 (1.28-3.68)] and diagnosis of diabetes [2.72 (1.26-5.86)]. One-third of participants diagnosed with dyslipidemia reported a low-fat diet. Low-fat diet was associated with female gender [1.47 (1.17-1.86)]; older age [1.29 (0.89-1.87), 1.71 (1.18-2.48) and 2.01 (1.33-3.03) for [50-60[, [60-70[ and [70+ years, respectively]; hypolipidemic drug treatment [OR=1.68 (1.29-2.18)]; current smoking [0.70 (0.51-0.96)] and obesity [0.67 (0.45-1.00)]. Approximately half of participants diagnosed with diabetes reported an antidiabetic diet. Antidiabetic diet was associated with current smoking [0.44 (0.22-0.88)] and antidiabetic drug treatment [OR=3.26 (1.81-5.86)].

CONCLUSION

Dietary management of CVRFs is seldom implemented in Switzerland.

Origin and age of the earliest Martian crust from meteorite NWA 7533

The ancient cratered terrain of the southern highlands of Mars is thought to hold clues to the planet's early differentiation, but until now no meteoritic regolith breccias have been recovered from Mars. Here we show that the meteorite Northwest Africa (NWA) 7533 (paired with meteorite NWA 7034) is a polymict breccia consisting of a fine-grained interclast matrix containing clasts of igneous-textured rocks and fine-grained clast-laden impact melt rocks. High abundances of meteoritic siderophiles (for example nickel and iridium) found throughout the rock reach a level in the fine-grained portions equivalent to 5 per cent CI chondritic input, which is comparable to the highest levels found in lunar breccias. Furthermore, analyses of three leucocratic monzonite clasts show a correlation between nickel, iridium and magnesium consistent with differentiation from impact melts. Compositionally, all the fine-grained material is alkalic basalt, chemically identical (except for sulphur, chlorine and zinc) to soils from Gusev crater. Thus, we propose that NWA 7533 is a Martian regolith breccia. It contains zircons for which we measured an age of 4,428 ± 25 million years, which were later disturbed 1,712 ± 85 million years ago. This evidence for early crustal differentiation implies that the Martian crust, and its volatile inventory, formed in about the first 100 million years of Martian history, coeval with earliest crust formation on the Moon and the Earth. In addition, incompatible element abundances in clast-laden impact melt rocks and interclast matrix provide a geochemical estimate of the average thickness of the Martian crust (50 kilometres) comparable to that estimated geophysically.

The cAMP-specific phosphodiesterase PDE4D3 is regulated by phosphatidic acid binding. Consequences for cAMP signaling pathway and characterization of a phosphatidic acid binding site

Hormones and growth factors induce in many cell types the production of phosphatidic acid (PA), which has been proposed to play a role as a second messenger. We have previously shown in an acellular system that PA selectively stimulates certain isoforms of type 4 cAMP-phosphodiesterases (PDE4). Here we studied the effect of endogenous PA on PDE activity of transiently transfected MA10 cells overexpressing the PA-sensitive isoform PDE4D3. Cell treatment with inhibitors of PA degradation, including propranolol, induced an accumulation of endogenous PA accompanied by a stimulation of PDE activity and a significant decrease in both cAMP levels and protein kinase A activity. Furthermore, in FRTL5 cells, which natively express PDE4D3, pretreatment with compounds inducing PA accumulation prevented both cAMP increase and cAMP-responsive element-binding protein phosphorylation triggered by thyroid-stimulating hormone. To determine the mechanism of PDE stimulation by PA, endogenous phospholipids were labeled by preincubating MA10 cells overexpressing PDE4D3 with [(32)P]orthophosphate. Immuno- precipitation experiments showed that PA was specifically bound to PDE4D3, supporting the hypothesis that PDE4D3 activation occurs through direct binding of PA to the protein. PA binding site on PDE4D3 was characterized by engineering deletions of selected regions in the N-terminal regulatory domain of the enzyme. Deletion of amino acid residues 31-59 suppressed both PA-activating effect and PA binding, suggesting that this region rich in basic and hydrophobic residues contains the PA binding site. These observations strongly suggest that endogenous PA can modulate cAMP levels in intact cells, through a direct activation of PDE4D3.

Involvement of type 4 cAMP-phosphodiesterase in the myogenic differentiation of L6 cells

Myogenic cell differentiation is induced by Arg(8)-vasopressin, whereas high cAMP levels and protein kinase A (PKA) activity inhibit myogenesis. We investigated the role of type 4 phosphodiesterase (PDE4) during L6-C5 myoblast differentiation. Selective PDE4 inhibition resulted in suppression of differentiation induced by vasopressin. PDE4 inhibition prevented vasopressin-induced nuclear translocation of the muscle-specific transcription factor myogenin without affecting its overall expression level. The effects of PDE4 inhibition could be attributed to an increase of cAMP levels and PKA activity. RNase protection, reverse transcriptase PCR, immunoprecipitation, Western blot, and enzyme activity assays demonstrated that the PDE4D3 isoform is the major PDE4 expressed in L6-C5 myoblasts and myotubes, accounting for 75% of total cAMP-hydrolyzing activity. Vasopressin cell stimulation caused a biphasic increase of PDE4 activity, which peaked at 2 and 15 min and remained elevated for 48 h. In the continuous presence of vasopressin, cAMP levels and PKA activity were lowered. PDE4D3 overexpression increased spontaneous and vasopressin-dependent differentiation of L6-C5 cells. These results show that PDE4D3 plays a key role in the control of cAMP levels and differentiation of L6-C5 cells. Through the modulation of PDE4 activity, vasopressin inhibits the cAMP signal transduction pathway, which regulates myogenesis possibly by controlling the subcellular localization of myogenin.

Regulation of PDE-4 cAMP phosphodiesterases by phosphatidic acid

Phosphatidic acid (PA) has been previously shown to activate specifically some of the isoforms of type 4 cylic nucleotide phosphodiesterases (PDE-4) in an acellular system. In the present work, we have investigated the mechanism of PA-activating effect by using a recombinant PA-sensitive isoform, PDE-4D3. The enzyme was specifically activated by acidic phospholipids, but not by zwitterionic phospholipids or anionic detergents. The importance of the role of PA acidic groups in the activation process was confirmed by studying the influence of pH and ionic strength on activation. Crosslinking experiments suggested that PA might influence the ability of PDE-4D3 to form dimers. Binding studies performed with radiolabeled PA showed that PA binds to a PDE-4D3 preparation in a saturable manner. Specifically bound PA was displaced by anionic, but not by zwitterionic phospholipids. With a preparation of PDE-4B2, a PDE-4 isoform insensitive to PA activation, PA binding was only displaced by high concentrations of unlabeled PA, suggesting that high-affinity PA binding sites are only present on PDE-4D3. These data support the hypothesis that PA-activating effect depends on direct binding of the effector on specific sites carried by the PDE-4D3 protein.

Note sur quelques complications tardives observées à la suite de l'anesthésie du zébu (Bos indicus) par le couple "Immobilon" - "Revivon"

Les auteurs décrivent des accidents tardifs observés chez des zébus Gobra à robe claire expérimentalement traités avec un neuroleptanalgés ique (Immobilon) et son antagoniste (Revivon). Ils attribuent ces phénomènes à un processus de photosensibilisation induit par le dérivé de la phénothiazine contenu dans l'Immobilon. Ils en discutent les raisons, proposent un traitement efficace en insistant sur la prudence dont il convient de faire preuve dans leur utilisation chez des bovins à robe claire, par grand soleil et forte chaleur