Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide

The results of both chemical and XPS analysis pointed out that desilication of highly siliceous ZSM-5 of Si/Al = 164 was more effective in the surface zone than in the bulk, contrary to zeolite ZSM-5 of Si/Al = 31.6. According to the IR studies in parent zeolite the concentration of protonic sites was very close to the concentration of Al indicating that all Al atoms can form Si-OH-Al. The results of our quantitative IR studies strongly support the realumination thesis, i.e. some Al atoms extracted in basic solutions are subsequently reinserted forming new acidic hydroxyls. In desilicated zeolites all Al atoms were able to form protonic sites, however part of them dehydroxylated during the activation of zeolite producing Lewis acid sites according to the stoichiometry: one protonic site was transformed into one Lewis site. Low temperature nitrogen adsorption revealed that the alkaline treatment of highly siliceous zeolite with 0.2 M NaOH/TBAOH mixture produced mesopores of smaller diameter and narrower pore size distribution than in the case of zeolite of medium Si/Al ratio. This result can be explained by low concentration of Al which similarly as TBA(+) cations plays the role of pore directing agents (PDA). Contrary to TEA(+), the presence of Al in desilication mixture, led to the formation of larger pores. Therefore, in highly siliceous zeolite TBA(+) played dominant role as PDA producing narrower pores. Highly siliceous zeolite with uniform distribution of relatively narrow pores may be useful catalyst or catalyst support. The influence of desilication temperature on porosity development was also investigated. The increase of desilication temperature from 338 to 353 K resulted in both more extensive demetalation (more Si and Al is extracted) and the distinct increase of the volume and surface of mesopores. Both lower concentration of protonic sites and higher concentration of Lewis sites confirmed partial zeolite destruction upon desilication at elevated temperature. The experiments of pivalonitrile sorption followed by IR spectroscopy showed a significant increase of accessibility of acid sites to bulky pivalonitrile molecules. (C) 2012 Elsevier Inc. All rights reserved.The research was partially carried out with the equipment purchased thanks to the financial support of the European Regional Development Fund in the framework of the Polish Innovation Economy Operational Program (Contract No. POIG.02.01.00-12-023/08).Sadowska, K.; Góra-Marek, K.; Drozdek, M.; Kustrowski, P.; Datka, J.; Martínez-Triguero, J.; Rey Garcia, F. (2013). Desilication of highly siliceous zeolite ZSM-5 with NaOH and NaOH/tetrabutylamine hydroxide. Microporous and Mesoporous Materials. 168:195-205. https://doi.org/10.1016/j.micromeso.2012.09.033S19520516

Identification of Domains and Amino Acids Essential to the Collagen Galactosyltransferase Activity of GLT25D1

Collagen is modified by hydroxylation and glycosylation of hydroxylysine residues. This glycosylation is initiated by the β1,O galactosyltransferases GLT25D1 and GLT25D2. The structurally similar protein cerebral endothelial cell adhesion molecule CEECAM1 was previously reported to be inactive when assayed for collagen glycosyltransferase activity. To address the cause of the absent galactosyltransferase activity, we have generated several chimeric constructs between the active human GLT25D1 and inactive human CEECAM1 proteins. The assay of these chimeric constructs pointed to a short central region and a large C-terminal region of CEECAM1 leading to the loss of collagen galactosyltransferase activity. Examination of the three DXD motifs of the active GLT25D1 by site-directed mutagenesis confirmed the importance of the first (amino acids 166–168) and second motif (amino acids 461–463) for enzymatic activity, whereas the third one was dispensable. Since the second DXD motif is incomplete in CEECAM1, we have restored the motif by introducing the substitution S461D. This change did not restore the activity of the C-terminal region, thereby showing that additional amino acids were required in this C-terminal region to confer enzymatic activity. Finally, we have introduced the substitution Q471R-V472M-N473Q-P474V in the CEECAM1-C-terminal construct, which is found in most animal GLT25D1 and GLT25D2 isoforms but not in CEECAM1. This substitution was shown to partially restore collagen galactosyltransferase activity, underlining its importance for catalytic activity in the C-terminal domain. Because multiple mutations in different regions of CEECAM1 contribute to the lack of galactosyltransferase activity, we deduced that CEECAM1 is functionally different from the related GLT25D1 protein

Improved management of lysosomal glucosylceramide levels in a mouse model of type 1 Gaucher disease using enzyme and substrate reduction therapy

Gaucher disease is caused by a deficiency of the lysosomal enzyme glucocerebrosidase (acid βâ glucosidase), with consequent cellular accumulation of glucosylceramide (GLâ 1). The disease is managed by intravenous administrations of recombinant glucocerebrosidase (imiglucerase), although symptomatic patients with mild to moderate type 1 Gaucher disease for whom enzyme replacement therapy (ERT) is not an option may also be treated by substrate reduction therapy (SRT) with miglustat. To determine whether the sequential use of both ERT and SRT may provide additional benefits, we compared the relative pharmacodynamic efficacies of separate and sequential therapies in a murine model of Gaucher disease (D409V/null). As expected, ERT with recombinant glucocerebrosidase was effective in reducing the burden of GLâ 1 storage in the liver, spleen, and lung of 3â monthâ old Gaucher mice. SRT using a novel inhibitor of glucosylceramide synthase (Genzâ 112638) was also effective, albeit to a lesser degree than ERT. Animals administered recombinant glucocerebrosidase and then Genzâ 112638 showed the lowest levels of GLâ 1 in all the visceral organs and a reduced number of Gaucher cells in the liver. This was likely because the additional deployment of SRT following enzyme therapy slowed the rate of reaccumulation of GLâ 1 in the affected organs. Hence, in patients whose disease has been stabilized by intravenously administered recombinant glucocerebrosidase, orally administered SRT with Genzâ 112638 could potentially be used as a convenient maintenance therapy. In patients naïve to treatment, ERT followed by SRT could potentially accelerate clearance of the offending substrate.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147062/1/jimd0281.pd

A Plant-Derived Recombinant Human Glucocerebrosidase Enzyme—A Preclinical and Phase I Investigation

Gaucher disease is a progressive lysosomal storage disorder caused by the deficiency of glucocerebrosidase leading to the dysfunction in multiple organ systems. Intravenous enzyme replacement is the accepted standard of treatment. In the current report, we evaluate the safety and pharmacokinetics of a novel human recombinant glucocerebrosidase enzyme expressed in transformed plant cells (prGCD), administered to primates and human subjects. Short term (28 days) and long term (9 months) repeated injections with a standard dose of 60 Units/kg and a high dose of 300 Units/kg were administered to monkeys (n = 4/sex/dose). Neither clinical drug-related adverse effects nor neutralizing antibodies were detected in the animals. In a phase I clinical trial, six healthy volunteers were treated by intravenous infusions with escalating single doses of prGCD. Doses of up to 60 Units/kg were administered at weekly intervals. prGCD infusions were very well tolerated. Anti-prGCD antibodies were not detected. The pharmacokinetic profile of the prGCD revealed a prolonged half-life compared to imiglucerase, the commercial enzyme that is manufactured in a costly mammalian cell system. These studies demonstrate the safety and lack of immunogenicity of prGCD. Following these encouraging results, a pivotal phase III clinical trial for prGCD was FDA approved and is currently ongoing.ClinicalTrials.gov NCT00258778

Diagnosis and treatment of thyroid cancer in children in the multicenter analysis in Poland for PPGGL

Introduction: Differentiated thyroid carcinoma (DTC) in children presents different biological behavior in comparison to adults. Authors presents preliminary results of multicenter analysis concerning incidence, diagnostics and treatment of DTC in children. Material and methods: The study is a retrospective analysis of 107 pediatric patients from 14 academic centers based on the data from 2000 to 2005 obtained by questionnaire in hospitals involved in the treatment of DTC in children. Results: Papillary thyroid cancer was diagnosed in 83 children, follicular thyroid cancer in 10 children and medullary thyroid cancer in 14 children. Incidence of DTC in children was estimated between 18 and 23 cases per year. The biggest group of patients consisted of children between 11 and 15 years of age, with girls to boys ratio 3.3 : 1. Clinically DTC in children presented most often as solitary thyroid nodule. Cervical lymphadenopathy was observed in 42% of patients. Intraoperative verification indicated metastatic nodes in 50% of children. Low stage DTC predominated (T1 in 36% and T2 in 26% of children). One step surgery was performed in 65% of children with DTC, two step surgery in 25% of patients. I131 therapy was undertaken in 80% of children. Lung metastases were indicated in post therapeutic studies in 14% of children with DTC. Prophylactic thyroidectomies were performed in 79% of children in the group of patients with MTC and RET gene mutations. Conclusions: The necessity of introduction of unified therapeutic standard in children with DTC in Poland is underlined.Wstęp: Zróżnicowane raki tarczycy (DTC, differentiated thyroid carcinoma) występują u dzieci rzadko. Większość przypadków wykrywanych jest w wieku 11-17 lat. W odróżnieniu od dorosłych DTC u dzieci prezentują odmienne zachowanie biologiczne. Mała liczba przypadków DTC w poszczególnych ośrodkach oraz względnie łagodny ich przebieg utrudniają ocenę występowania i leczenia DTC u dzieci w Polsce, uzależniając ją od wysiłków włożonych w uzyskanie rzetelnych danych. Autorzy przedstawiają wstępne wyniki analizy wieloośrodkowej dotyczące występowania, diagnostyki i leczenia DTC u dzieci. Materiał i metody: Podjęte badania są retrospektywną analizą obejmującą lata 2000-2005, opartą na danych z historii chorób uzyskanych z ankiet rozesłanych do ośrodków dla dzieci i dorosłych podejmujących leczenie DTC. Do analizy zgłoszono 107 pacjentów z 14 ośrodków akademickich w Polsce. Analizie poddano wiek i płeć dzieci z DTC, wielkość i lokalizację zmian w tarczycy, sposoby rozpoznawania DTC, rodzaje i zakres wykonywanych zabiegów operacyjnych oraz leczenie uzupełniające izotopem J131. Wyniki: Raka brodawkowatego stwierdzono u 83 dzieci, pęcherzykowego u 10 dzieci, a rdzeniastego u 14 dzieci. Częstość występowania DTC u dzieci w Polsce wahała się między 18 a 23 przypadkami rocznie. W województwach: mazowieckim i połączonych wielkopolskim i lubuskim wykazano w okresie 2000-2005 wyższą (24 i 25) częstość występowania DTC, w pozostałych województwach wykazywano od 2 do 10 przypadków DTC. Największą grupę pacjentów stanowiły dzieci w wieku 11-15 lat, a stosunek dziewcząt do chłopców wynosił 3,3 : 1. Klinicznie DTC prezentowały się najczęściej jako pojedyncze guzki tarczycy. Limfadenopatię szyjną w badaniu klinicznym stwierdzono u 42% pacjentów, a śródoperacyjnie u 50% dzieci. U większości pacjentów dominowały niższe stopnie zaawansowania DTC (T1 u 36% i T2 u 26% dzieci). Operacje jednoetapowe wykonano u 65% dzieci, operacje dwuetapowe u 25% dzieci, a profilaktyczne tyreoidektomie u 79% dzieci z grupy pacjentów z rakiem rdzeniastym tarczycy (MTC, medullary thyroid cancinoma) i mutacją genu Ret. Leczenie izotopowe J131 podjęto u 80% dzieci. Przerzuty do płuc w scyntygrafii poterapeutycznej wykazano u 14% dzieci z DTC. Wnioski: We wnioskach podkreśla się konieczność wdrożenia na terenie całego kraju ujednoliconego i ocenianego na podstawie obiektywnych przesłanek sposobu postępowania z dziećmi z DTC

Potential range of impact of an ecological trap network: the case of timber stacks and the Rosalia longicorn

Although the negative impact of timber stacks on populations of saproxylic beetles is a well-known phenomenon, there is relatively little data concerning the scale of this impact and its spatial aspect. Beech timber stored in the vicinity of the forest can act as an ecological trap for the Rosalia longicorn (Rosalia alpina), so in this study we have attempted to determine the spatial range of the impact of a network of timber stacks. Timber stacks in the species’ range in the study area were listed and monitored during the adult emergence period in 2014–2016. Based on published data relating to the species’ dispersal capabilities, buffers of four radii (500, 1000, 1600, 3000 m) were delineated around the stacks and the calculated ranges of potential impact. The results show that the percentage of currently known localities of the Rosalia longicorn impacted by stacks varies from 19.7 to 81.6%, depending on the assumed impact radius. The percentage of forest influenced by timber stacks was 77% for the largest-radius buffer. The overall impact of the ecological trap network is accelerated by fragmentation of the impact-free area. It was also found that forests situated close to the timber stacks where the Rosalia longicorn was recorded were older and more homogeneous in age and species composition than those around stacks where the species was absent. Such results suggest that timber stacks act as an ecological trap in the source area of the local population