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•Cefaclor yield of 91% was obtained in DES-buffer (7:3, v/v) co-solvent system.•Penicillin acylase immobilized on magnetic nanocrystalline cellulose was prepared.•The introduction of ...DES enhanced the yield and selectivity of cefaclor synthesis.
Deep eutectic solvent (DES), has been considered as a new type of green solvent applied in enzymatic systems. Here, we reported DES-buffer co-solvent as a novel reaction medium for high efficient synthesis of cefaclor by penicilin acylase immobilized on magnetic nanocrystalline cellulose. Effect of DES composition, DES-buffer ratio, temperature, pH, substrate ratio and substrate concentration was systematically investigated. In co-solvent consisting of choline chloride (ChCl):glycol-buffer (7:3, v/v), conversion of 7-ACCA was 94%, synthesis to hydrolysis ratio was 1.8, and yield of cefaclor reached 91%, higher than that in aqueous buffer with optimized yield of 84%, showing the great potential of DES as organic solvent alternative. To the best of our knowledge, this is the first example of biosynthesis of cefaclor in the DES-buffer co-solvent.
•A commercial SiC is very active in photocatalytic ozonation of aqueous organics.•UV is more powerful than visible light in the SiC catalyzed combining process.•Photo generated electron reduction of ...oxygen and ozone are the key steps.•The high conducting band position of SiC benefit to the electron reduction.•The activity of the commercial SiC is comparable to P25 TiO2.
SiC is a newly developed photocatalyst, but it is often used together with a co-catalyst rather than solely for its relatively low activity. Here we reported the high activity of a commercial SiC in a photocatalysis and ozone combined process (photocatalytic ozonation). The commercial SiC showed very weak activity in photocatalysis of oxalic acid (OA) and para-hydroxybenzoic acid (PHBA) degradation, and its performance in catalytic ozonation was also not satisfied. However, the organics degradation and mineralization rates dramatically increased in the SiC photocatalytic ozonation. The different operation parameters were optimized, and the main reactive radicals in this process and its generation pathways were studied. It was found that photo-generated electron reduction of ozone and oxygen are the main pathways to produce hydroxyl radical, which was responsible to the high oxidizing ability of this process.
Implementation of a penicillin allergy skin test Nagao-Dias, Aparecida Tiemi; Pereira, Ana Carla; Silva, Michelly Freitas e ...
Brazilian Journal of Pharmaceutical Sciences,
09/2009, Volume:
45, Issue:
3
Journal Article
Peer reviewed
Open access
The penicillin allergy skin testing is the only accurate and reliable test for penicillin hypersensitivity mediated by IgE. It is useful for identifying patients with doubtful history of allergy. ...Positive test for major and minor determinants presents a positive predictive value of 50% and negative predictive value of 99%. In Brazil, the Ministry of Health suggests a protocol for in house made reagents, since they are not commercially available. As the referred protocol does not mention some important details about the test procedures, we propose in the present work to implement them, critically evaluating each step in order to allow the protocol establishment at any health service, with quality and safety.
O teste cutâneo para alergia imediata a penicilina é o único teste validado internacionalmente, sendo que sua grande utilidade reside na avaliação de pacientes com história positiva de alergia a penicilina. O teste positivo para determinantes principais e secundários da penicilina apresenta um valor preditivo positivo de 50% e valor preditivo negativo de 99%. Em nosso meio, o Ministério de Saúde disponibiliza um protocolo para o preparo dos reagentes, uma vez que os mesmos não estão disponíveis comercialmente. Como o referido protocolo não apresenta maiores detalhes sobre o cuidado relativo às etapas de preparo das soluções, bem como faltam algumas considerações no que tange a realização do teste, propusemo-nos no presente trabalho operacionalizar o teste, avaliando de forma crítica e minuciosa cada etapa, de forma que outros profissionais possam reproduzi-lo de maneira mais segura e eficaz.
Iako se ne zna točna učestalost alergije na lijekove, pripisuje joj se oko 1/10 svih neželjenih reakcija na lijekove. Neželjene reakcije na penicilin javljaju se u 0,7 – 10 % ljudi koji primaju ...penicilin. Stvarna učestalost alergije na penicilin još je manja, budući da su se u prošlosti mnoge nealergijske nuspojave antibiotika pripisivale alergiji. U pacijenata kod kojih postoji sumnja na alergiju na penicilin važno je utvrditi alergološki status. Nepotrebno izbjegavanje upotrebe penicilina, koji je jeftin i u većini slučajeva siguran lijek, povećava troškove bolničkog liječenja, morbiditet i mortalitet pacijenata. Suprotno, primjena penicilina u pacijenata koji su alergični na njega može dovesti do ozbiljnih neželjenih posljedica, uključujući i smrtni ishod. Kožni alergološki test najbrža je i optimalna metoda utvrđivanja alergije na penicilin. Provokacijski test penicilinom primjenjuje se u pacijenata s malom sumnjom na alergiju kod kojih su rezultati kožnog testa negativni uz anamnestičke neuvjerljive podatke za alergijsku reakciju. Liječenje antibiotikom različitog kemijskog sastava i mehanizma djelovanja ili desenzibilizacija moguće su terapijske opcije u pacijenata s dokazanom alergijom na penicilin. Desenzibilizacija je postupak kojim se izaziva privremena tolerancija na penicilin. Indikacije za primjenu su teška septička stanja uzrokovana bakterijama za koje ne postoji učinkovitiji lijek, a provodi se pod strogim nadzorom liječnika. Komercijalno dostupni alergološki dijagnostički testovi danas se smatraju sigurnim načinom utvrđivanja alergološkog statusa u pacijenata sa sumnjom na alergiju na penicilin.
FUNDAMENTO: Penicilina G benzatina a cada 3 semanas é o protocolo padrão para a profilaxia secundária para febre reumática recorrente. OBJETIVO: Avaliar o efeito da penicilina G benzatina em ...Streptococcus sanguinis e Streptococcus oralis em pacientes com doença valvular cardíaca, devido à febre reumática com recebimento de profilaxia secundária. MÉTODOS: Estreptococos orais foram avaliados antes (momento basal) e após 7 dias (7º dia) iniciando-se com penicilina G benzatina em 100 pacientes que receberam profilaxia secundária da febre reumática. Amostras de saliva foram avaliadas para verificar a contagem de colônias e presença de S. sanguinis e S. oralis. Amostras de saliva estimulada pela mastigação foram serialmente diluídas e semeadas em placas sobre agar-sangue de ovelhas seletivo e não seletivo a 5% contendo penicilina G. A identificação da espécie foi realizada com testes bioquímicos convencionais. Concentrações inibitórias mínimas foram determinadas com o Etest. RESULTADOS: Não foram encontradas diferenças estatísticas da presença de S. sanguinis comparando-se o momento basal e o 7º dia (p = 0,62). No entanto, o número existente de culturas positivas de S. oralis no 7º dia após a Penicilina G benzatina apresentou um aumento significativo em relação ao valor basal (p = 0,04). Não houve diferença estatística existente entre o momento basal e o 7º dia sobre o número de S. sanguinis ou S. oralis UFC/mL e concentrações inibitórias medianas. CONCLUSÃO: O presente estudo mostrou que a Penicilina G benzatina a cada 3 semanas não alterou a colonização por S. sanguinis, mas aumentou a colonização de S. oralis no 7º dia de administração. Portanto, a susceptibilidade do Streptococcus sanguinis e Streptococcus oralis à penicilina G não foi modificada durante a rotina de profilaxia secundária da febre reumática utilizando a penicilina G. (Arq Bras Cardiol. 2012; online.ahead print, PP.0-0)BACKGROUND: Benzathine penicillin G every 3 weeks is the standard protocol for secondary prophylaxis for recurrent rheumatic fever. OBJECTIVE: Assess the effect of Benzathine penicillin G on Streptococcus sanguinis and Streptococcus oralis in patients with cardiac valvular disease due to rheumatic fever receiving secondary prophylaxis. METHODS: Oral streptococci were evaluated before (baseline) and after 7 days (day 7) with Benzathine penicillin G in 100 patients receiving routine secondary rheumatic fever prophylaxis. Saliva samples were evaluated for colony count and presence of S. sanguinis and S. oralis. Chewing-stimulated saliva samples were serially diluted and plated onto both nonselective and selective 5% sheep blood agar containing penicillin G. The species were identified using conventional biochemical tests. Minimal inhibitory concentrations were determined with the Etest. RESULTS: No statistical differences were found in the presence of S. sanguinis comparing baseline and day 7 (p = 0.62). However, the existing number of positive cultures of S. oralis on day 7 after Benzathine penicillin G presented a significant increase compared to baseline (p = 0.04). No statistical difference was found between baseline and day 7 concerning the number of S. sanguinis or S. oralis CFU/mL and median minimal inhibitory concentrations. CONCLUSION: This study showed that Benzathine penicillin G every 3 weeks did not change the colonization by S. sanguinis, but increased colonization of S. oralis on day 7 of administration. Therefore, susceptibility of Streptococcus sanguinis and Streptococcus oralis to penicillin G was not modified during the penicillin G routine secondary rheumatic fever prophylaxis. (Arq Bras Cardiol. 2012; online.ahead print, PP.0-0)
Benzathine penicillin G every 3 weeks is the standard protocol for secondary prophylaxis for recurrent rheumatic fever.
Assess the effect of Benzathine penicillin G on Streptococcus sanguinis and ...Streptococcus oralis in patients with cardiac valvular disease due to rheumatic fever receiving secondary prophylaxis.
Oral streptococci were evaluated before (baseline) and after 7 days (day 7) with Benzathine penicillin G in 100 patients receiving routine secondary rheumatic fever prophylaxis. Saliva samples were evaluated for colony count and presence of S. sanguinis and S. oralis. Chewing-stimulated saliva samples were serially diluted and plated onto both nonselective and selective 5% sheep blood agar containing penicillin G. The species were identified using conventional biochemical tests. Minimal inhibitory concentrations were determined with the Etest.
No statistical differences were found in the presence of S. sanguinis comparing baseline and day 7 (p = 0.62). However, the existing number of positive cultures of S. oralis on day 7 after Benzathine penicillin G presented a significant increase compared to baseline (p = 0.04). No statistical difference was found between baseline and day 7 concerning the number of S. sanguinis or S. oralis CFU/mL and median minimal inhibitory concentrations.
This study showed that Benzathine penicillin G every 3 weeks did not change the colonization by S. sanguinis, but increased colonization of S. oralis on day 7 of administration. Therefore, susceptibility of Streptococcus sanguinis and Streptococcus oralis to penicillin G was not modified during the penicillin G routine secondary rheumatic fever prophylaxis.
The aim of this work was the optimization of 6-aminopenicillanic acid
obtaining procedure by using immobilized penicillin acylase from E. coli. The
reaction of penicillin G hydrolysis to 6-APA ...catalyzed by free and
immobilized penicillin acylase was considered. In order to realize the set
aim, it was necessary to make a choice of carriers and methods for
immobilization of the enzyme, to optimize enzyme immobilization procedure in
terms of enzyme loading and activity yield. Also, the obtained biocatalysts
were characterized and the differences in kinetic parameters of free and
immobilized penicillin acylase were examined. An appropriate reactor solution
for performing the reaction with the immobilized enzyme and the operational
stability of the system were examined. In the first part of the thesis free
penicillin acylase (PAC) from Escherichia coli was characterized and its
catalytic properties were studied in the reaction of hydrolysis of penicillin
G as a reference system. This characterization was necessary in order to
determine the differences in the activities of the free and immobilized
enzyme. Therefore, the protein content in the commercial enzyme preparation,
specific activity, pH and temperature profile, thermal stability and the
values of kinetic constants (Michaelis constant and maximal reaction rate)
were determined. Likewise, the inhibition of PAC activity by substrate and
reaction products (6-aminopenicillanic acid and phenylacetic acid) in the
system with free enzyme was studied and types of inhibition and inhibition
constant values were determined In the second part of the thesis the research
has been focused on stabilizing the enzyme by different procedures. In with
this aim, several procedures of chemical immobilization of the enzyme on
various natural and synthetic polymers (Sepabeads with different functional
groups and chitosan), as well as immobilization of the previously chemically
modified enzyme were studied. In addition, possibilities of direct binding of
penicillin acylase by amino groups in the enzyme to the epoxy groups of the
carriers, the binding of the enzyme to the carriers activated with
glutaraldehyde, as well as binding of the previously modified enzyme to the
carriers with amino groups were investigated. The chemical modification of
the enzyme was carried out using dialdehyde derivatives of natural
polysaccharides (starch and alginate) that had been previously obtained by
periodate oxidation method. The modified enzyme bound to the amino carriers
by introduced aldehyde groups that were not essential for its activity. In
the case of all applied immobilization methods, resulting biocatalysts were
fully characterized for use in the reaction of hydrolysis of penicillin G and
compared to the reference system with the free enzyme. In this regard, enzyme
loadings on carriers, specific activities, enzyme coupling yields, pH and
temperature profiles, thermal stabilities and possibilities of reuse were
studied. Reaction kinetics and effects of inhibition by substrate and
reaction products on penicillin acylase immobilized on chitosan microbeads
were studied. On the basis of the obtained results, appropriate kinetic
models for the free and immobilized enzyme were derived. In addition to the
choice of carrier and immobilization method, optimization of enzymatic
hydrolysis of penicillin G requires determination of process parameters and
the regime including the appropriate bioreactor configuration. With this aim,
the initial kinetics of hydrolysis penicillin G by PAC immobilized on
chitosan microbeads was studied in two reactor systems: packed-bed with and
without recirculation. The obtained kinetic results were analyzed using
various kinetic models that consider the different types of inhibition.
Compared to data available in the literature, it can be concluded that within
this thesis were developed several systems with immobilized penicillin
acylase that had the same or even higher efficiency than commercial
immobilized system in terms of activity, operational stability and space-time
yield of reactor. Therefore, this thesis represents a significant practical
contribution to this issue. Also, the results of this thesis contribute to
the understanding of mechanisms and kinetics of hydrolysis of penicillin G in
different systems with immobilized penicillin acylase, especially the types
and effects of inhibition, as well as optimization of the configuration and
the corresponding modes of bioreactors.
Osnovni cilj ove doktorske disertacije je bio optimizacija postupka dobijanja
6- aminopenicilanske kiseline primenom imobilisane penicilin-acilaze iz E.
coli. Pri tome je razmatrana reakcija hidrolize prirodnog penicilina G do
6-APA katalizovane slobodnom i imobilisanom penicilin-acilazom. Da bi se
realizovao postavljeni cilj bilo je potrebno izvršiti izbor nosača i metode
za imobilizaciju enzima, optimizovati postupak imobilizacije enzima sa
aspekta mase vezanog enzima i prinosa aktivnosti, okarakterisati dobijeni
biokatalizator i ispitati razlike u kinetičkim parametrima slobodne i
imobilisane penicilin-acilaze, izabrati odgovarajuće reaktorsko rešenje za
izvođenje reakcije sa imobilisanim enzimima i ispitati operativnu stabilnost
sistema. U prvom delu rada je izvršena karakterizacija slobodne
penicilin-acilaze iz Escherichia coli i ispitana su njena katalitička
svojstva u reakciji hidrolize penicilina G kao referentnom sistemu. Ova
karakterizacija je bila neophodna da bi se utvrdile razlike u delovanju
slobodnog i imobilisanog enzima. U tom cilju utvrđen je sadržaj proteina u
komercijalnom enzimskom preparatu, specifična aktivnost, pH i temperaturni
profil, termalna stabilnost, kao i vrednosti kinetičkih konstanti, i to
Mihaelisove konstante i maksimalne brzine reakcije. Isto tako, ispitan je
uticaj inhibicije supstratom u višku i proizvodima reakcije na brzinu
reakcije u sistemu sa slobodnim enzimom i u tom cilju je određena vrsta
inhibicije i vrednosti konstanti inhibicije. U drugom delu rada osnovni cilj
istraživanja je bio usmeren na stabilizaciju enzima različitim postupcima.
Pri tome je ispitano nekoliko postupaka hemijske imobilizacije enzima na
različitim prirodnim i sintetskim polimerima (Sepabeads sa različitim
funkcionalnim grupama i hitozan), kao i postupak imobilizacije prethodno
hemijski modifikovanog enzima. U radu je ispitana mogućnost direktnog
vezivanja penicilin-acilaze preko amino grupa u molekulu za epoksidne grupe
nosača, zatim vezivanje enzima za nosač koji je prethodno aktiviran
glutaraldehidom ili vezivanje prethodno modifikovanog enzima za nosače sa
amino grupama. Hemijska modifikacija enzima je izvedena pomoću dialdehidnih
derivata prirodnih polisaharida (skroba i alginata) koji su prethodno
dobijeni oksidacijom perjodatnom metodom. Ovako dobijeni glikozilovani enzim
se vezao za amino-nosače preko uvedenih aldehidnih grupa koje nisu od
esencijalnog značaja za njegovu aktivnost. U slučaju svih primenjenih metoda
imobilizacije, dobijeni biokatalizatori su bili u potpunosti okarakterisani
za primenu u reakciji hidrolize penicilina G i upoređeni sa referentnim
sistemom sa slobodnim enzimom. Određene su mase vezanog enzima na nosaču,
specifične aktivnosti, prinosi imobilizacije, pH i temperaturni profili,
termalne stabilnosti i mogućnosti ponovljenih upotreba. Ispitana je i
kinetika reakcije i efekti inhibicije supstratom i proizvodima reakcije
penicilin-acilazom imobilisanom na hitozanskim mikročesticama i na osnovu
dobijenih rezultata izveden je odgovarajući kinetički model za slobodan i
imobilisan enzim. S obzirom da je za optimizaciju enzimskog postupka
hidrolize penicilina G, pored izbora nosača i metode za imobilizaciju enzima,
potrebno podesiti i procesne parametre i način izvođenja procesa, izabrati
konfiguraciju i odgovarajući režim rada bioreaktora, za penicilin-acilazu
imobilisanu na hitozanske mikročestice ispitana je početna kinetika hidrolize
penicilina G u dva reaktorska sistema: protočnom bioreaktoru sa pakovanim
slojem čestica biokatalizatora i protočnom bioreaktoru sa pakovanim slojem sa
recirkulacijom reakcione smeše. Na dobijene kinetičke rezultate primenjeni su
različiti kinetički modeli koji uzimaju u obzir različite vrste inhibicije.
Na osnovu nekih dostupnih podataka u literaturi, može se zaključiti da je u
okviru ove teze razvijeno nekoliko imobilisanih sistema sa
penicilin-acilazama koji imaju istog reda veličine ili čak veću efikasnost od
komercijalnih imobilisanih sistema u pogledu aktivnosti, operativne
stabilnosti i prostorno-vremenskog prinosa reaktora. Time ova doktorska teza
predstavlja značajan praktičan doprinos ovoj problematici. Takođe, rezultati
ove teze doprinose razumevanju mehanizama i kinetike hidrolize penicilina G u
različitim sistemima sa imobilisanom penicilin-acilazom, naročito vrstama i
efektima inhibicije, kao i optimizaciji konfiguracije i odgovarajućeg režima
rada bioreaktora.
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