Cathodes for fuel cells using proton-conducting Li2SO4–Al2O3 electrolyte

The performances of three widely different cathode materials (Pt, strontium-doped lanthanum manganite (LSM), and NiO) have been compared for use with proton conducting Li₂SO₄–Al₂O₃ composite electrolyte, using H₂S–air and H₂–air fuel cells operating at 600 °C. Surface analysis and electrochemical techniques were used to characterize fresh and used electrode materials. Pt or LSM cathodes each became covered with Li₂SO₄ and Al₂O₃ and, as a consequence, the fuel cells showed poor performance. In contrast, the NiO cathode catalyst did not become covered with Li₂SO₄ and good fuel cell performance was achieved. Exceptionally good current densities of over 100 mA/cm² and power densities of over 30 mW/cm² were obtained for H₂S–air fuel cells having Mo–Ni–S anode catalysts. Slight agglomeration of NiO particles during fuel cell operation had only a minor effect on performance.     

New lipid biochemical aspects in the pathogenesis of a follicular keratinization disorder in acne vulgaris

Follicular hyperkeratinization of the epithelium of the acroinfundibulum of sebaceous follicles is one of the primary events in the pathogenesis of acne vulgaris. Oral treatment with 13-cis-retinoic acid can reduce these hyperkeratoses. In order to determine whether follicular hyperkeratinization is related to disturbances of epidermal follicular lipids, we analyzed the lipids of initial comedones from 10 patients with nodulocystic acne before and after a 6th weeks oral therapy with 13-cis-retinoic acid (0.7 mg/kg body weight). The treatment with retinoid resulted in a significant increase of epidermal lipids (free sterols: +34%; ceramides: +19%, whereas the lipids of sebaceous origin decreased (glycerides: -36%). The mass ratio of free sterols to cholesterol sulfate increased by 86% compared to pre-treatment levels. These findings support the hypothesis that local follicular deficiencies of epidermal lipids due to increased sebum secretion might induce abnormal follicular keratinization.     

Are deficiencies of prostaglandin-E-mediated immunoregulation involved in increased IgE synthesis of atopic mononuclear cells in vitro?

We demonstrate that spontaneous in vitro immunoglobulin E synthesis of atopic peripheral blood mononuclear cells could be suppressed by the addition of 10(-6) M to 10(-5) M prostaglandin E1 (PGE1) or PGE2. Impaired suppressor T lymphocyte maturation and function in atopic individuals are explained by an insufficient transmission of prostaglandin E (PGE) signals during thymic lymphocyte differentiation as well as an impaired ability of the atopic immune system to activate suppressor T cells by PGE-mediated feed back mechanisms. Decreased levels of 6-desaturated PGE-precursor fatty acids in plasma, T lymphocytes, monocytes, adipose tissue and breast milk have been observed in atopic individuals. These insights might offer a novel approach to the prevention of atopic disease by substitution of the atopic pregnant and nursing woman and her newborn infant with long-chain omega-6-fatty acids.     

Functional magnetic resonance imaging monitoring of pathological changes in rodent livers during hyperoxia and hypercapnia

Liver diseases and regeneration are associated with hemodynamic changes denoting pathological alterations. Determining and monitoring physiological and pathological liver changes is essential for diagnostic and therapeutic objectives. Our aim was to determine the feasibility of functional magnetic resonance imaging (fMRI) during hypercapnia and hyperoxia for monitoring liver pathology. Liver fMRI images were acquired in rodents following acute bleeding, partial hepatectomy, and fibrosis. Results were quantitated and confirmed by histology. Changes induced by hyperoxia and hypercapnia following hemorrhage significantly correlated with the percentage of blood loss, reflecting lower liver perfusion and diminished vessel responsiveness to gas saturation. Hepatectomy resulted in an early decline in signal intensity changes due to hyperoxia, suggesting a decrease in liver perfusion and blood content. Following hepatectomy, signal intensity changes due to hypercapnia increased, signifying a change in liver perfusion from a mainly portal to a more arterial source. Two weeks after induction of fibrosis, signal intensity changes due to hypercapnia became much lower and those due to hyperoxia were much higher than those in normal livers, reflecting the increased perfusion due to the inflammatory process as confirmed by histologic analysis. With fibrosis progression, signal intensity changes induced by hypercapnia and hyperoxia were gradually attenuated, indicating structural and functional alterations of the liver vasculature during fibrosis. CONCLUSION: In various liver pathologies, fMRI response to hypercapnia and hyperoxia is sensitive to changes in liver hemodynamic status involved in hepatic damage or recovery; thus, this technique may offer an additional noninvasive diagnostic tool for evaluation and follow-up of liver diseases by means of examining perfusion-related alterations.     

Expression of the chemokine receptor CCR2 on immature B cells negatively regulates their cytoskeletal rearrangement and migration

Immature B cells are targeted to specific areas in the spleen, where a fraction of these cells receive signals that induce them to mature and participate in the immune response. In this study, we show that the C-C chemokine receptor 2 (CCR2) is transcribed in immature B cells, while its message is dramatically down-regulated at the mature stage. CCR2-deficient cells exhibit up-regulation of chemokine-induced actin polymerization, migration, and homing to the lymph nodes of immature B cells. In addition, we demonstrate that control of homing by CCR2 is mediated by its ligand, CCL2/JE, which is secreted by B cells and down-regulates the stromal derived factor-1 (SDF-1) signaling cascade. Thus, this study describes an additional, previously uncharacterized, role for CCR2 and its ligand as negative regulators of the homing of immature B cells.     

Clopidogrel tapering as a strategy to attenuate platelet rebound phenomenon in patients with bare-metal stents

Early clustering of adverse cardiovascular events after abrupt cessation of clopidogrel has been reported in patients with acute coronary syndromes. A platelet rebound phenomenon may contribute to this increased thrombotic risk and a gradual drug tapering may attenuate this proposed platelet effect. Accordingly, we aimed to assess the effect of clopidogrel tapering on platelet reactivity. Twenty patients who underwent elective percutaneous coronary interventions with bare metal stents receiving 3 months of clopidogrel therapy (75 mg daily) were randomized to either of two discontinuation strategies: (1) Off group–abrupt drug cessation or (2) Tapering group–receiving clopidogrel 75 mg every other day for 4 weeks duration. Light transmission aggregometry, induced by ADP (5 and 10 μM) and collagen, was measured at four time-points (at baseline and 2, 4 and 6 weeks after randomization). In the off group, there was an early rise in platelet reactivity at 2 weeks after abrupt drug cessation compared to baseline, as measured by ADP 5 μmol/l (39.6 ± 2.8 vs. 67.9 ± 6.0, P < 0.001). The tapering regimen suppressed this rebound platelet aggregation by ADP 5 μmol/l at 2 weeks (P = 0.001) and 4 weeks (P = 0.001). Similar results were found with ADP 10 μmol/l and collagen agonists. Abrupt cessation of clopidogrel results in an early rise in platelet aggregability in patients with BMS that is attenuated by a tapering regimen. Clopidogrel administration every other day may achieve similar levels of platelet inhibition as full dose therapy. Further investigations evaluating clopidogrel tapering strategies and their potential clinical impact are warranted.     

Endoscopic dacryocystorhinostomy among the old and oldest-old populations - A case control study

ObjectiveDespite increased risks of nasolacrimal duct obstruction (NLDO) with age, and the continuous growth of the old population proportion, data on endoscopic dacryocystorhinostomy (eDCR) among the old is lacking. This study aims to evaluate long-term eDCR efficacy and safety in the old and oldest-old population.MethodsA retrospective case-control study of patients aged 80 ≤ (oldest-old) and 65–79 (old) compared with younger controls who underwent eDCR, between 2002 and 2017. Pre-, intra- and postoperative factors were collected using an integrated hospital-community system. Success rates were analyzed and measured at the first visit following surgery (immediate success), and after five years. Demographics, comorbidities, complications rates, and outcomes were compared between the groups.ResultsThe study groups included 52 oldest-old patients (mean age 83.4 ± 3.6), 127 old patients (72.3 ± 4.14) and 142 control patients (57.8 ± 18.0). The immediate and success rates were 94.2%, 93.7% and 90.8% and five-year success rates were 80.0%, 76.6% and 80% among oldest-old, old and controls, respectively. No significant differences in success rates were found, even despite higher comorbidity rates among the study's group (96 and 92.8% vs. 63.2%, among oldest-old, old and controls respectively, p <0.001). Intra- and postoperative complications rates were low in all groups.ConclusionsAmong older population, including oldest-old and old, eDCR safety and long-term outcomes are comparable with younger patients, suggesting that eDCR should be offered to NLDO patients, regardless of age.     

Morbidity and mortality of hospitalized patients with diffuse idiopathic skeletal hyperostosis

Diffuse idiopathic skeletal hyperostosis (DISH) has been associated with various metabolic disorders considered to be cardiovascular risk factors such as obesity, diabetes mellitus, hyperinsulinemia, and hyperlipidemia. To evaluate morbidity and mortality of hospitalized patients with DISH admitted to the department of medicine. One hundred patients from a cohort of 1020 consecutive patients, aged 45 years and more, admitted to the department of medicine were diagnosed as suffering from DISH. Another group of 100 patients, age- and gender matched, admitted without DISH, served as controls. Clinical and demographic characteristics, diagnoses on admission, previous chronic diseases, chronic medical therapy, laboratory tests, and the rates of in-hospital mortality and readmissions within 1 month of discharge were collected from the hospital database, for the two groups. Uncompensated or paroxysmal atrial fibrillation was more often encountered on admission in patients with DISH (p=0.038). Patients with DISH were more likely to suffer from elevated body mass index, arterial hypertension, diabetes mellitus, and previous cerebral vascular accidents, although the differences did not reach statistical significance. However, significantly more patients had an electrocardiographic evidence of left ventricular hypertrophy (p=0.03). The mortality rate was similar between the two groups. The lack of significant associations for cardiovascular risk factors such as diabetes mellitus, hypertension, and high BMI should be interpreted cautiously considering the characteristics of the control group. Identification of comorbid conditions and proper therapeutic interventions may prove useful in reducing the morbidity and mortality associated with this disorder.