Search

A high efficiency nanocomposite photocatalyst is reported. Multiwall carbon nanotubes (MWNTs) were coated with titania. Two distinct types of nanocomposites were synthesized with variation in the synthetic procedure. One of the nanocomposites is based on a core of arc-discharge synthesized multiwall carbon nanotubes; whereas the other is based on a core of chemical vapor deposition (CVD) grown MWNTs. The nanocomposites have a similar appearance in transmission electron microscopy pictures in that they have a core of MWNTs that are chemically bonded to a few nanometer thick layer of pure anatase phase of titania. Yet they show a dramatically different photocatalytic behavior when they are compared on the basis of rates of photocatalytic decomposition of an organic dye in aqueous media following the Langmuir-Hinshelwood mechanism. This article focuses on the analysis of the differences in the nanocomposites using X-Ray Photoelectron Spectroscopy (XPS). XPS spectra of these materials indicate that there are distinct differences. However, they also show that both share C-O-Ti bonds that transform the carbon in the carbon nanotubes into a dopant for the anatase titania. This doping seems to be essential for long wavelength, i.e. visible light induced photocatalysis.

This chapter provides an overview of the metal-catalyzed dehydrocyclization of alkylaromatics and presents reaction mechanisms that govern these reactions. Catalytic cyclization is a very important reaction, both commercially and theoretically. Monoalkylaromatics and ortho-substituted dialkylaromatics containing at least three carbon atoms in the side chains can easily undergo dehydrocyclization to form an additional ring. Cyclizations of alkylaromatics can be classified in many different ways, such as the new ring can have five or six (or very rarely more or fewer) carbon atoms. Cyclization can be catalyzed by acids and by metals. The presence of the aromatic ring enhances the rate of dehydrocyclization; alkylaromatics dehydrocyclize faster than paraffins. The rate of dehydrocyclization increases with the number of aromatic rings within the reacting molecule.

Patienten mit einem Zweikammerschrittmacher leiden häufig unter Herzinsuffizienz. Der Einfluß der oberen Grenzfrequenz auf die kardiopulmonale Belastbarkeit bei Patienten mit und ohne Herzinsuffizienz ist nicht bekannt. Daher wurde bei 20 Patienten mit einem wegen eines höhergradigen AV-Blocks implantierten Zweikammerschrittmacher (16 VDD-Systeme, 4 DDD-Systeme) die obere Grenzfrequenz (OGF) auf 110, 120 oder 130/min randomisiert programmiert. In monatlichen Abständen wurde mittels Spiroergometrie die Sauerstoffaufnahme (VO2), die Belastbarkeit in Watt und die erreichte Herzfrequenz an der anaeroben Schwelle (AT) und bei Maximalbelastung ermittelt. Neun Patienten (71±12 Jahre) zeigten in der Spiroergometrie Zeichen einer mittelschweren bis schweren Herzinsuffizienz (Weber C/D, Gruppe I), während 11 Patienten (60±6 Jahre) in der Spiroergometrie keine bis mäßige Zeichen der Herzinsuffizienz zeigten (Weber A/B, Gruppe II). In Gruppe II erreichten die Patienten bei einer OGF von 130/min eine höhere VO2-AT (17,3±3,9 ml/min/kg) gegenüber einer OGF von 110/min (13,7±4,0 ml/min/kg, p<0,001), entsprechend einer Steigerung um 26%. Auch die maximale Sauerstoffaufnahme VO2maxund die Belastung an der anaeroben Schwelle waren in Gruppe II unter der höheren OGF von 130/min signifikant höher als bei 110/min (20,5±4,5 ml/min/kg vs. 18,2±5,3 ml/min/kg, p=0,031, und 98±29 Watt vs. 86±27 Watt, p=0,04). In der Gruppe I war die Sauerstoffaufnahme an der anaeroben Schwelle (VO2-AT) bei einer OGF von 110/min (11,1±4,0 ml/min/kg) höher, wenn auch nicht signifikant, als bei der OGF von 130/min (9,2±2,6 ml/min/kg; p=0,052), entsprechend einer Verbesserung um 24%. Im Streßechokardiogramm fanden sich unter Belastung (VVI-Stimulation bis max. 130/min) bei allen Patienten der Gruppe I, jedoch nur bei einem Patienten der Gruppe II neu aufgetretene Wandbewegungsstörungen. Der Wandbewegungsscoreindex in der Gruppe I stieg von 1,20±0,24 in Ruhe auf 1,54±0,28 unter Belastung (p<0,001), während sich in der Gruppe II kein signifikanter Unterschied zeigte (1,00±0 vs. 1,06±0,19; p=n.s.). Patienten mit Zweikammerschrittmachern ohne relevante Herzinsuffizienz (Weber A/B) profitieren von einer Programmierung der OGF auf höhere Frequenzen, hingegen ist bei mittelschwerer bis schwerer Herzinsuffizienz (Weber C/D) eine Begrenzung der OGF auf niedrigere Werte vorteilhaft. Die mögliche Ursache ist eine bei höheren Frequenzen auftretende Myokardischämie, wie gezeigt durch die Streßechokardiographie. Patients with a dual chamber pacemaker often suffer from chronic heart failure. The influence of the upper tracking rate on cardiac performance in patients with and without congestive heart failure is unknown. Therefore, twenty patients with a dual chamber pacemaker implanted for high degree AV block were randomly programmed to upper tracking rates of 110, 120, and 130 bpm. Oxygen uptake (VO2), work capacity, and heart rate were determined at the anaerobic threshold (AT) and at peak exercise using spiroergometry every 4 weeks. Nine patients (71±12 years) had evidence for advanced heart failure (Weber C/D, group I); 11 patients (60±6 years) had no or only mild heart failure (Weber A/B, group II). Patients in group II achieved a higher mean VO2-AT at 130 bpm (17.3±3.9 ml/min/kg) than at 110 bpm (13.7±4.0 ml/min/kg; p=0.001). Maximum oxygen uptake and work capacity at the anaerobic threshold were also significantly higher in group II with an upper tracking rate of 130 bpm than at 110 bpm (20.5±4.5 ml/min/kg vs. 18.2±5.3 ml/min/kg, p=0.031, and 98±29 W vs. 86±27 W, p=0.04). In group I, mean oxygen uptake at the anaerobic threshold (VO2-AT) was higher at 110 bpm (11.1±4.0 ml/min/kg) than at 130 bpm, although of only borderline statistical significance (9.2±2.6 ml/min/kg; p=0.052). In group I a higher upper rate decreased VO2-AT by 24%, whereas in group II the higher upper rate improved aerobic capacity by 26%. Stressechocardiography (VVI pacing with a maximum tracking rate of 130 bpm) revealed new wall motion abnormalities in all patients of group II. Wall motion score index increased from 1.20±0.24 at rest to 1.54±0.28 under stress (p<0.001) in group I, but not in group II (1.00±0 vs. 1.06±0.19; p=n.s.). Thus, carriers of dual chamber pacemakers with no or mild heart failure (Weber A/B) benefit from higher programmed upper rates. In contrast, patients with more advanced heart failure (Weber C/D) improve aerobic capacity with lower programmed upper rates. This may be caused by exercise-induced ischemia in group I as indicated by stressechocardiography.

In end-stage heart failure due to idiopathic dilated cardiomyopathy ß1-adrenoceptors are downregulated and G1a-proteins are upregulated. The aim of the present study was to investigate the influence of the angiotensin-converting enzyme inhibitor captopril on ß-adrenoceptor density and Gia-proteins in sequential endomyocardial biopsies. Nineteen patients with mild to moderate congestive heart failure due to idiopathic dilated cardiomyopathy (NYHA Class II–III) were studied before and after 8–11 weeks of therapy. Patients were randomised into a captopril and a control group; 9 patients received captopril 12.5–50 mg per day, (divided in 2–3 doses) p.o. in addition to “conventional” therapy with digoxin and diuretics, and 10 controls received “conventional” therapy only. Echocardiography, spiroergometry, right heart catheterisation and endomyocardial biopsies were performed before (baseline) and after treatment. Compared to baseline, captopril increased total ß-adrenoceptor density by selectively increasing ß1-adrenoceptors (31.6 vs 41.2 fmol·mg-1; p<0.05) but had no significant effect on Gia-proteins. The results indicate that treatment with angiotensin-converting enzyme inhibitors partly restores myocardial ß1-adrenoceptor density, and this action effect may contribute to the clinical improvement of patients with idiopathic dilated cardiomyopathy treated in this way.

Bei der Diagnostik der Abstoßungsreaktion nach Herztransplantation stellt die endomyokardiale Rechtsherzbiopsie mit histomorphologischer Bewertung den “Goldstandard” dar. Schwere akute Abstoßungsreaktionen (Grad 3A/3B, ISHLT) nach Herztransplantation erfordern eine sofortige hochdosierte immunsuppressive Therapie, wobei die histomorphologische Differenzierung zur nichttherapiepflichtigen Abstoßung (Grad 2) oft schwierig ist. Ziel der Studie war die Verbesserung der differentialdiagnostischen Abgrenzung therapiebedürftiger Abstoßungen durch Quantifizierung der Proliferation des interstitiellen Infiltrates in der Biopsie. 322 konsekutive endomyokardiale Biopsate von 48 herztransplantierten Patienten wurden immunohistochemisch mit dem monoklonalen Antikörper MIB-1, der gegen das proliferationsassoziierte Antigen Ki 67 gerichtet ist, untersucht. Zellproliferationen fanden sich in 50,6% aller Biopsien: Diese verteilten sich auf solche mit fehlender oder mit milder Abstoßung (0, 1A, 1B) mit 47,0%, verglichen zu 88,0% bei mäßiger und schwerer Abstoßung. (2, 3A, 3B) (p<0,01). Proliferierte Zellen waren in 66,0% fokal oder perivaskulär, in 34,0% diffus im Interstitium verteilt. Die Anzahl proliferierender Zellen pro Biopsie, nicht aber deren Verteilung, korrelierte mit der Schwere der Abstoßungsreaktion: 0,7% in Grad 0, 1,4%/5,0% bei 1A/1B, 8,5% bei Grad 2, bis 18,7% bei 3A/3B und 2,7% bei R1 (p<0,01, ccorr=0,65). Die Anzahl proliferierender mononukleärer Zellen im endomyokardialen Infiltrat bei akuter Abstoßung ist direkt proportional zu deren Schweregrad und ist hilfreich bei der schwierigen histologischen Differenzierung von Stadium 3A/3B. The histological grading of endomyocardial biopsies still represents the gold standard in the diagnosis of cardiac allograft rejections. Severe acute rejections (grade 3A/3B, ISHLT) after heart transplantation require immediate high-dose immunosuppressive therapy. The histomorphological differentiation to the rejection requiring no therapy (grade 2) is often difficult. The aim of this study is the improvement of the diagnostic identification of therapyrequiring rejections using quantification of cell proliferation in the inflammatory infiltrate of biopsies. 322 consecutive endomyocardial biopsies from 48 heart allograft recipients were immunohistochemically investigated using the monoclonal antibody MIB-1 binding selectively to the proliferation associated antigen Ki 67. Fifty percent of all biopsies showed cell proliferation: 47.0% in absent or mild rejection (0, 1A, 1B) compared to 88.0% in moderate to severe rejection (2, 3A/3B) (p<0.01). Proliferating cells were arranged in a focal or perivascular pattern in 66.0% and diffuse in 34.0%. The quantity of proliferating cells per biopsy – but not the pattern – correlated with the grade of rejection: 0.7% in grade 0, 1.4%/5% in 1A/1B, 8.5% in grade 2 up to 18.7% in 3A/3B, and 2.7% in R1 (p<0.01, ccorr=0.65). The amount of proliferating mononuclear cells in the inflammatory infiltrate in acute cardiac allograft rejection is proportional to the severity of the rejection and thus an aid in the difficult histological differentiation of grade 3A/3B.

A reversed-phase, high-performance liquid chromatographic (HPLC) procedure, which is specific and quantitative for lidocaine hydrochloride, epinephrine, and methylparaben, was developed for the analysis of lidocaine hydrochloride and lidocaine hydrochloride with epinephrine solutions for injection. Epinephrine sulfonic acid and adrenochrome are separated in this system. Also separated are lidocaine and methylparaben and their respective degradation products, 2, 6-xylidine and p-hydroxybenzoic acid. The analysis requires that three detectors (two UV and one electrochemical) be connected in series. By using this arrangement, lidocaine hydrochloride and methylparaben are quantitated by UV at 254 and 280 nm, respectively, while epinephrine is quantitated electrochemically. The method is simple, accurate, precise, and rapid. No sample preparation or internal standard is necessary, and only a 2-μl sample volume is required for analysis. Chromatographic conditions include a μBondapak CN column and a mobile phase of 0.01 M 1-octanesulfonic acid sodium salt, 0.1 mMedetate disodium, 2% acetic acid, 2% acetonitrile, and 1% methanol in water.

Polyglucosan body diseases in adults, contrary to infantile cases (Andersen's disease or type IV glycogenosis or amylopectinosis), are usually not associated with a significant deficiency of the branching enzyme (=amylo-1,4-1,6 transglucosidase). We, therefore, report on a 19-year-old male with complete branching enzyme deficiency presenting with severe myopathy, dilative cardiomyopathy, heart failure, dysmorphic features, and subclinical neuropathy. His 14-year-old brother had similar symptoms and was erroneously classified by a previous muscle biopsy as having central core disease but could later be identified as also having polyglucosan body myopathy. The skeletal muscle, endomyocardiac, and sural nerve biopsies as well as the autopsy revealed extraordinarily severe deposits of polyglucosan bodies not only in striated and smooth muscle fibers, but also in histiocytes, fibroblasts, perineurial cells, axons and astrocytes. Occasional paracrystalline mitochondrial inclusions were also noted. Thus, this patient represents to our knowledge the first juvenile, familial case of polyglucosan body disease with total branching enzyme deficiency and extensive polyglucosan body storage.

Abstract: Objective: In human heart failure downregulation of β-adrenoceptors and upregulation of Gi-protein α-subunits (Giα) results desensitization of the myocardial β-adrenergic signal transduction pathway and reduced positive inotropic effects of catecholamines. Metoprolol treatment has been shown to restore the reduced β-adrenoceptor density in dilated cardiomyopathy. The main objective of the present study was to investigate whether metoprolol also decreases the elevated inhibitory Giα levels in patients suffering from congestive heart failure. Methods:Total Giα was determined by pertussis toxin-catalysed ADP ribosylation and β1- and β2-adrenoceptor densities by radioligand binding in right ventricular myocardial biopsies of 18 patients with dilated or ischaemic cardiomyopathy (NYHA II–IV) before and after 3 months of therapy. Nine controls were treated with conventional therapy only [diuretics, digitalis, nitrates, angiotensin-converting enzyme (ACE) inhibitors], and nine received the β1-selective blocker metoprolol in addition (mean 98 ± 12 mg daily). Results:In biopsies from patients treated with metoprolol, Giα significantly decreased to 74% of predrug value and total β-adrenoceptor increased by a selective increase in β1- adrenoceptors (44.7 vs 34.0 fmol ⋅ mg−1 protein). These effects were accompanied by significantly increased oxygen uptake at the anaerobic threshold (8.65 vs 6.95 ml ⋅ kg−1⋅ min−1). In the control group no significant changes in biochemical and clinical parameters occurred. Conclusion:Metoprolol partly reverses Giα-upregulation and β-adrenoceptor downregulation in heart failure, which might contribute to the clinical improvement of patients treated with β-blockers.

Ohne Zusammenfassung:

ATKINS1, in 1945, reported on the productivity of the English Channel as estimated by two independent methods. The silicate turnover indicated a far lower productivity than did the phosphate turnover, and from this he deduced that only a relatively small fraction of the phytoplankton could consist of forms with siliceous skeletons. Knight-Jones and Walne2later showed that the very small nannoplanktonic form, Chromulina pusilla, was present in English Channel waters in numbers averaging about 1,000 per ml. They quoted other work showing that as much as 90 per cent of the phytoplankton may be small enough to pass through a fine silk tow net, and 40 per cent through a No. 2 Whatman filter paper.