bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intestinal enzymatic metabolism of drugs
Authors: Sarti Federica , Barthelmes Jan , Iqbal Javed , Hintzen Fabian , Bernkop-Schnürch Andreas 
Published: February 2011

Abstract

Objectives
The intestinal stability of perorally administered drugs has so far been determined using simulated intestinal fluid containing porcine pancreatin (SIF/P), as human gastrointestinal fluids are in most cases not available. In this study the metabolism of six low molecular mass drugs in SIF/P was compared with that in freshly collected porcine intestinal juice and on excised porcine intestinal mucosa.

Methods
The drugs used were oseltamivir, atazanavir, diloxanide, diltiazem, cephalothin and cefoxitin. Metabolism studies were carried out by incubating each drug in the in-vitro models and by analysing the percentage of unmodified remaining drug at fixed time points.

Key findings
Three drugs showed higher degradation on porcine mucosa compared with that in SIF/P and for five compounds a significantly higher metabolism in collected porcine intestinal juice versus SIF/P was observed. Metabolism of diloxanide furoate in collected intestinal juice, for example, was 40-fold higher compared with SIF/P. Moreover, the involvement of different metabolic pathways in porcine mucosa and intestinal juice was observed for cephalothin, being metabolized to desacetylcephalothin and thienyl-acetylglycine, whereas these metabolites were not found in SIF/P. In addition, diltiazem solution (0.25% m/v) was found to be significantly degraded in intestinal juice whereas its metabolism in SIF/P was negligible.

Conclusions
These findings demonstrated that the use of SIF/P for evaluation of presystemic drug metabolism could be highly misleading. Incubation of drugs in freshly collected porcine intestinal juice will likely lead to the improvement of the mimicry of body conditions to evaluate presystemic drug metabolism.
Encapsulation of vinorelbine into cholesterol-polyethylene glycol coated vesicles: drug loading and pharmacokinetic studies
Authors: Li ChunLei , Cui JingXia , Wang CaiXia , Zhang Lan , Xiu Xian , Li YongFeng , Wei Na , Li YanHui , Zhang Li 
Published: February 2011

Abstract

Objectives
Pegylated liposome formulations of vinorelbine with prolonged circulation half-life (t½) are desirable. However, DSPE-PEG could affect vinorelbine loading into vesicles due to electrostatic interactions. To resolve this problem, chol-PEG was used to prepare pegylated liposomal vinorelbine and the factors affecting drug loading and plasma pharmacokinetics were investigated.

Methods
Vinorelbine was loaded into liposomes using a novel triethylamine 5-sulfosalicylate gradient. The effects of cholesterol and chol-PEG on drug loading were investigated. Pharmacokinetic studies were performed in normal KunMing mice treated with different liposomal vinorelbine formulations. To clarify the effects of chol-PEG on membrane permeability, drug release experiments were performed based on the fluorescence dequenching phenomenon of a fluorescence marker.

Key findings
In contrast to DSPE-PEG, even at high PEG grafting density (∼8.3 mol%), chol-PEG had no effect on vinorelbine loading into HSPC/cholesterol (3 : 1, mass ratio) vesicles. However, for the formulations with low cholesterol content (HSPC/cholesterol 4 : 1), loading efficiency decreased with increasing chol-PEG content. In vivo, the vinorelbine t½ of low cholesterol formulations decreased with increasing chol-PEG content, but for high cholesterol liposomes, the maximum vinorelbine t½ was achieved at ∼3 mol% chol-PEG grafting density. The resulting vinorelbine circulation t½ was ∼9.47 h, which was greater than that of non-pegylated liposomes (∼5.55 h). Drug release experiments revealed that chol-PEG might induce membrane defects and concomitant release of entrapped marker, especially at high chol-PEG density.

Conclusions
Through the investigation of the effects of chol-PEG and cholesterol, an optimum pegylated liposomal vinorelbine formulation with prolonged t½ was achieved. In plasma, the membrane defect induced by chol-PEG may counteract the long circulation characteristics that chol-PEG afforded. When these two opposite effects reached equilibrium, the maximum vinorelbine t½ was achieved.
Anti-inflammatory activity of the non-peptidyl low molecular weight radical scavenger IAC in carrageenan-induced oedema in rats
Authors: Corsi Lorenzo , Zavatti Manuela , Geminiani Elisa , Zanoli Paola , Baraldi Mario 
Published: February 2011

Abstract

Objective
In this research we investigated the anti-inflammatory activity of a non-peptidyl low molecular weight radical scavenger (IAC) in an acute and chronic animal model of inflammation.

Methods
For this purpose the effect of IAC (10, 25, 50 mg/kg) was tested in rats on the associated behavioral responses to subsequent inflammatory and noxious challenges, such as hind paw oedema induced by intra-plantar injection of carrageenan and granuloma induced by subcutaneous implant of a cotton pellet, using indometacin (2.5 mg/kg) as reference drug. Moreover, the serum level of several cytokines was tested in the animal treated (or not) with IAC (50 mg/kg) both in the absence and presence of carrageenan-induced inflammation.

Key findings
IAC showed a significant anti-inflammatory activity in both in acute and chronic models of inflammation. In addition IAC down regulated significantly the serum levels of interleukin (IL) 2 and IL6 whereas it increased the serum concentration of IL1α and glutathione.

Conclusion
Although it remains to be elucidated whether or not the antioxidant property of IAC is directly responsible for the modulation of the tested cytokines, these results suggest IAC to be a possible candidate for a novel anti-inflammatory compound
Preparation of ONO-1301-loaded poly(lactide-co-glycolide) microspheres and their effect on nerve conduction velocity
Authors: Hazekawa Mai , Sakai Yoshiki , Yoshida Miyako , Haraguchi Tamami , Morisaki Tomomi , Uchida Takahiro 
Published: February 2011

Abstract

Objectives
The aim of this study was to prepare poly(lactide-co-glycolide) (PLGA) microspheres containing ONO-1301, a novel long-acting prostacyclin agonist with thromboxane synthase inhibitory activity, with 10% of drug released in the initial burst and a sustained-release period of about 3 weeks after administration. The effect of PLGA type (molecular weight and the lactide/glycolide (L/G) ratio in PLGA), the preparative conditions and the particle size on the in-vitro release profile were examined. The effect of optimized ONO-1301-loaded PLGA microspheres on delayed nerve condition velocity (NCV) was investigated in streptozotocin (STZ) induced diabetic rats.

Methods
ONO-1301 PLGA microspheres were produced by the oil-in-water emulsion/solvent evaporation method. Drug release from the prepared microspheres was monitored in phosphate buffer solution at 37°C for 4 weeks by high-performance liquid chromatography. The in-vivo study was performed in STZ-induced diabetic rats treated with optimized ONO-1301 PLGA microspheres (10 mg/kg by intramuscular or subcutaneous injection every 3 weeks). NCV was measured in the thigh 4, 8 and 12 weeks after induction.

Key findings
The molecular weights of PLGA, the L/G ratio in PLGA and the particle diameter all affected the length of the sustained release period. Drug release from microspheres containing PLGA 5050 (MW 50 000, L/G 50/50), with an average diameter of about 30 µm, could be sustained for 3 weeks in vitro. In the in-vivo study, delayed NCV was significantly increased by treatment with these ONO-1301 PLGA microspheres once every 3 weeks, in comparison with vehicle only.

Conclusion
Local intramuscular injection of sustained-release ONO-1301 PLGA microspheres improved delayed NCV in STZ-induced diabetic rats.
Development of Tetravalent, Bispecific CCR5 Antibodies with Antiviral Activity against CCR5 Monoclonal Antibody-Resistant HIV-1 Strains
Authors: Schanzer Jürgen , Jekle Andreas , Nezu Junichi , Lochner Adriane , Croasdale Rebecca , Dioszegi Marianna , Zhang Jun , Hoffmann Eike , Dormeyer Wilma , Stracke Jan , Schäfer Wolfgang , Ji Changhua , Heilek Gabrielle , Cammack Nick , Brandt Michael , Umana Pablo , Brinkmann Ulrich 
Published: February 2011

ABSTRACT

In this study, we describe novel tetravalent, bispecific antibody derivatives that bind two different epitopes on the HIV coreceptor CCR5. The basic protein formats that we applied were derived from Morrison-type bispecific antibodies: whole IgGs to which we connected single-chain antibodies (scFvs) via (Gly
4
Ser)

n

sequences at either the C or N terminus of the light chain or heavy chain. By design optimization, including disulfide stabilization of scFvs or introduction of 30-amino-acid linkers, stable molecules could be obtained in amounts that were within the same range as or no less than 4-fold lower than those observed with monoclonal antibodies in transient expression assays. In contrast to monospecific CCR5 antibodies, bispecific antibody derivatives block two alternative docking sites of CCR5-tropic HIV strains on the CCR5 coreceptor. Consequently, these molecules showed 18- to 57-fold increased antiviral activities compared to the parent antibodies. Most importantly, one prototypic tetravalent CCR5 antibody had antiviral activity against virus strains resistant to the single parental antibodies. In summary, physical linkage of two CCR5 antibodies targeting different epitopes on the HIV coreceptor CCR5 resulted in tetravalent, bispecific antibodies with enhanced antiviral potency against wild-type and CCR5 antibody-resistant HIV-1 strains.
Evaluations of Shorter Exposures of Contact Lens Cleaning Solutions against Fusarium oxysporum Species Complex and Fusarium solani Species Complex To Simulate Inappropriate Usage
Authors: Ramani Rama , Chaturvedi Vishnu 
Published: February 2011

ABSTRACT

An outbreak of
Fusarium
keratitis in contact lens users resulted in withdrawal of ReNu with MoistureLoc solution, although the exact cause of the outbreak remains enigmatic. We evaluated current and discontinued multipurpose cleaning solutions (MPSs; MoistureLoc, Equate, MultiPlus, and OptiFree Express) against plankton- and biofilm-derived cells of
Fusarium oxysporum
species complex (FOSC) and
F. solani
species complex (FSSC). The methods included a traditional assay based on CFU counts and a novel flow cytometry (FC) assay based on percent cell subpopulation (PCS) stained with two fluorochromes (Sytox Red and 5-chloromethylfluorescein diacetate). The tests were done with the respective manufacturers' recommended cleaning regimens (240 to 360 min) and under shorter exposures (15 to 60 min) to simulate inappropriate usage by the customers. FC assay measured PCS, which was available rapidly, in 5 to 7 h, whereas 24 to 48 h was needed for CFU counts, and there was good correlation between the two methods (
r
2
= 0.97). FC assays allowed identification of injured fungal cells, which are likely to be missed with growth assays. In general, a time- and inoculum-dependent survival pattern was seen for both FOSC and FSSC cells, and biofilm-derived cells were more resistant than plankton-derived cells. MultiPlus and Equate produced 100% sterilization of fungi even under shorter exposures. However, biofilm FOSC and FSSC cells survived for up to 4 h in MoistureLoc solution and up to 6 h in OptiFree Express solution under shorter exposure times. This finding was enigmatic, as OptiFree Express is not associated with any outbreak of
Fusarium
keratitis. This study provides additional support for possible roles that improper lens cleaning regimens and fungal biofilms could play as predisposing factors for
Fusarium
keratitis.
The Marine Sponge-Derived Polyketide Endoperoxide Plakortide F Acid Mediates Its Antifungal Activity by Interfering with Calcium Homeostasis
Authors: Xu Tao , Feng Qin , Jacob Melissa R. , Avula Bharathi , Mask Melanie M. , Baerson Scott R. , Tripathi Siddharth K. , Mohammed Rabab , Hamann Mark T. , Khan Ikhlas A. , Walker Larry A. , Clark Alice M. , Agarwal Ameeta K. 
Published: February 2011

ABSTRACT

Plakortide F acid (PFA), a marine-derived polyketide endoperoxide, exhibits strong inhibitory activity against the opportunistic fungal pathogens
Candida albicans
,
Cryptococcus neoformans
, and
Aspergillus fumigatus
. In the present study, transcriptional profiling coupled with mutant and biochemical analyses were conducted using the model organism
Saccharomyces cerevisiae
to investigate the mechanism of action of this compound. PFA elicited a transcriptome response indicative of a Ca
2+
imbalance, affecting the expression of genes known to be responsive to altered cellular calcium levels. Several additional lines of evidence obtained supported a role for Ca
2+
in PFA's activity. First, mutants lacking calcineurin and various Ca
2+
transporters, including pumps (Pmr1 and Pmc1) and channels (Cch1 and Mid1), showed increased sensitivity to PFA. In addition, the calcineurin inhibitors FK506 and cyclosporine strongly enhanced PFA activity in wild-type cells. Furthermore, PFA activated the transcription of a
lacZ
reporter gene driven by the calcineurin-dependent response element. Finally, elemental analysis indicated a significant increase in intracellular calcium levels in PFA-treated cells. Collectively, our results demonstrate that PFA mediates its antifungal activity by perturbing Ca
2+
homeostasis, thus representing a potentially novel mechanism distinct from that of currently used antifungal agents.
Benzimidazole Analogs Inhibit Human Herpesvirus 6
Authors: Prichard Mark N. , Frederick Samuel L. , Daily Shannon , Borysko Katherine Z. , Townsend Leroy B. , Drach John C. , Kern Earl R. 
Published: February 2011

ABSTRACT

Several benzimidazole nucleoside analogs, including 1H-β-
d
-ribofuranosyl-2-bromo-5,6-dichlorobenzimidazole (BDCRB) and 1H-β-
l
-ribofuranosyl-2-isopropylamino-5,6-dichlorobenzimidazole (maribavir [MBV]), inhibit the replication of human cytomegalovirus. Neither analog inhibited the related betaherpesvirus human herpesvirus 6 (HHV-6). Additional analogs of these compounds were evaluated against both variants of HHV-6, and two
l
-analogs of BDCRB had good antiviral activity against HHV-6A, as well as more modest inhibition of HHV-6B replication.
Molecular Detection of Mutations Associated with First- and Second-Line Drug Resistance Compared with Conventional Drug Susceptibility Testing of Mycobacterium tuberculosis
Authors: Campbell Patricia J. , Morlock Glenn P. , Sikes R. David , Dalton Tracy L. , Metchock Beverly , Starks Angela M. , Hooks Delaina P. , Cowan Lauren S. , Plikaytis Bonnie B. , Posey James E. 
Published: February 2011

ABSTRACT

The emergence of multi- and extensively drug-resistant tuberculosis is a significant impediment to the control of this disease because treatment becomes more complex and costly. Reliable and timely drug susceptibility testing is critical to ensure that patients receive effective treatment and become noninfectious. Molecular methods can provide accurate and rapid drug susceptibility results. We used DNA sequencing to detect resistance to the first-line antituberculosis drugs isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), and ethambutol (EMB) and the second-line drugs amikacin (AMK), capreomycin (CAP), kanamycin (KAN), ciprofloxacin (CIP), and ofloxacin (OFX). Nine loci were sequenced:
rpoB
(for resistance to RIF),
katG
and
inhA
(INH),
pncA
(PZA),
embB
(EMB),
gyrA
(CIP and OFX), and
rrs
,
eis
, and
tlyA
(KAN, AMK, and CAP). A total of 314 clinical
Mycobacterium tuberculosis
complex isolates representing a variety of antibiotic resistance patterns, genotypes, and geographical origins were analyzed. The molecular data were compared to the phenotypic data and the accuracy values were calculated. Sensitivity and specificity values for the first-line drug loci were 97.1% and 93.6% for
rpoB
, 85.4% and 100% for
katG
, 16.5% and 100% for
inhA
, 90.6% and 100% for
katG
and
inhA
together, 84.6% and 85.8% for
pncA
, and 78.6% and 93.1% for
embB
. The values for the second-line drugs were also calculated. The size and scope of this study, in numbers of loci and isolates examined, and the phenotypic diversity of those isolates support the use of DNA sequencing to detect drug resistance in the
M. tuberculosis
complex. Further, the results can be used to design diagnostic tests utilizing other mutation detection technologies.
Complementation of
Rickettsia rickettsii
RelA/SpoT Restores a Nonlytic Plaque Phenotype
Authors: Clark Tina R. , Ellison Damon W. , Kleba Betsy , Hackstadt Ted 
Published: February 2011

ABSTRACT

Spotted fever group rickettsiae are known to produce distinct plaque phenotypes. Strains that cause lytic infections in cell culture form clear plaques, while nonlytic strains form opaque plaques in which the cells remain intact. Clear plaques have historically been associated with more-virulent species or strains of spotted fever group rickettsiae. We have selected spontaneous mutant pairs from two independent strains of
Rickettsia rickettsii
, the virulent R strain and the avirulent Iowa strain. A nonlytic variant of
R. rickettsii
R, which typically produces clear plaques, was isolated and stably maintained. A lytic variant of the Iowa strain, which characteristically produces opaque plaques, was also selected and maintained. Genomic resequencing of the variants identified only a single gene disrupted in each strain. In both cases, the mutation was in a gene annotated as
relA
/
spoT
-like. In the Iowa strain, a single mutation introduced a premature stop codon upstream from region encoding the predicted active site of RelA/SpoT and caused the transition to a lytic plaque phenotype. In
R. rickettsii
R, the nonlytic plaque phenotype resulted from a single-nucleotide substitution that shifted a tyrosine residue to histidine near the active site of the enzyme. The intact
relA
/
spoT
gene thus occurred in variants with the nonlytic plaque phenotype. Complementation of the truncated
relA
/
spoT
gene in the Iowa lytic plaque variant restored the nonlytic phenotype. The
relA
/
spoT
mutations did not affect the virulence of either strain in a Guinea pig model of infection; R strain lytic and nonlytic variants both induced fever equally, and the mutation in Iowa to a lytic phenotype did not cause them to become virulent.
Preterm Infants Have Deficient Monocyte and Lymphocyte Cytokine Responses to Group B Streptococcus
Authors: Currie Andrew J. , Curtis Samantha , Strunk Tobias , Riley Karen , Liyanage Khemanganee , Prescott Susan , Doherty Dorota , Simmer Karen , Richmond Peter , Burgner David 
Published: February 2011

ABSTRACTGroup B streptococcus (GBS) is an important cause of early- and late-onset sepsis in the newborn. Preterm infants have markedly increased susceptibility and worse outcomes, but their immunological responses to GBS are poorly defined. We compared mononuclear cell and whole-blood cytokine responses to heat-killed GBS (HKGBS) of preterm infants (gestational age [GA], 26 to 33 weeks), term infants, and healthy adults. We investigated the kinetics and cell source of induced cytokines and quantified HKGBS phagocytosis. HKGBS-induced tumor necrosis factor (TNF) and interleukin 6 (IL-6) secretion was significantly impaired in preterm infants compared to that in term infants and adults. These cytokines were predominantly monocytic in origin, and production was intrinsically linked to HKGBS phagocytosis. Very preterm infants (GA, <30 weeks) had fewer cytokine-producing monocytes, but nonopsonic phagocytosis ability was comparable to that for term infants and adults. Exogenous complement supplementation increased phagocytosis in all groups, as well as the proportion of preterm monocytes producing IL-6, but for very preterm infants, responses were still deficient. Similar defective preterm monocyte responses were observed in fresh whole cord blood stimulated with live GBS. Lymphocyte-associated cytokines were significantly deficient for both preterm and term infants compared to levels for adults. These findings indicate that a subset of preterm monocytes do not respond to GBS, a defect compounded by generalized weaker lymphocyte responses in newborns. Together these deficient responses may increase the susceptibility of preterm infants to GBS infection.
Parity and Placental Infection Affect Antibody Responses againstPlasmodium falciparumduring Pregnancy
Authors: Mayor Alfredo , Rovira-Vallbona Eduard , Machevo Sonia , Bassat Quique , Aguilar Ruth , Quintó Llorenç , Jiménez Alfons , Sigauque Betuel , Dobaño Carlota , Kumar Sanjeev , Singh Bijender , Gupta Puneet , Chauhan Virander S. , Chitnis Chetan E. , Alonso Pedro L. , Menéndez Clara 
Published: February 2011

ABSTRACTWomen are at higher risk ofPlasmodium falciparuminfection when pregnant. The decreasing risk of malaria with subsequent pregnancies is attributed to parity-dependent acquisition of antibodies against placental parasites expressing variant surface antigens, VAR2CSA, that mediate placental sequestration through adhesion to chondroitin sulfate A (CSA). However, modulation of immunity during pregnancy may also contribute to increase the risk of malaria. We compared antibody responses among 30 Mozambican primigravidae and 60 multigravidae at delivery, 40 men, and 40 children. IgG levels were measured against the surface antigens of erythrocytes infected withP. falciparumisolated from 12 pregnant women (4 placental and 8 peripheral blood isolates) and 26 nonpregnant hosts. We also measured IgG levels against merozoite recombinant antigens and total IgG. PlacentalP. falciparuminfection was associated with increased levels of total IgG as well as IgG levels against merozoite antigens and parasite isolates from pregnant and nonpregnant hosts. We therefore stratified comparisons of antibody levels by placental infection. Compared to multigravidae, uninfected primigravidae had lower total IgG as well as lower levels of IgGs against peripheral blood isolates from both pregnant and nonpregnant hosts. These differences were not explained by use of bed nets, season at delivery, neighborhood of residence, or age. Compared to men, infected primigravidae had higher levels of IgGs against isolates from pregnant women and CSA-binding lines but not against other isolates, supporting the concept of a pregnancy-specific development of immunity to these parasite variants. Results of this study show that parity and placental infection can modulate immune responses during pregnancy against malaria parasites.
Toll-Like Receptor 9 Is Required for Full Host Resistance to
Mycobacterium
avium
Infection but Plays No Role in Induction of Th1 Responses
Authors: Carvalho Natália B. , Oliveira Fernanda S. , Durães Fernanda V. , de Almeida Leonardo A. , Flórido Manuela , Prata Luana O. , Caliari Marcelo V. , Appelberg Rui , Oliveira Sérgio C. 
Published: February 2011

ABSTRACT

To investigate the role of Toll-like receptor 9 (TLR9) in innate immunity to
Mycobacterium
avium
, TLR9, TLR2, and MyD88 knockout (KO) mice were infected with this bacterium. Bacterial burdens were higher in the spleens, livers, and lungs of infected TLR9 KO mice than in those of C57BL/6 mice, indicating that TLR9 is required for efficient control of
M
.
avium
infection. However, TLR9 KO or TLR2 KO spleen cells displayed normal
M
.
avium
-induced tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ) responses. This finding was confirmed by determining the number of splenic CD4
+
T cells producing IFN-γ by flow cytometry. Furthermore, TLR2 and MyD88, but not TLR9, played a major role in interleukin-12 and TNF-α production by
M
.
avium
-infected macrophages and dendritic cells (DCs). We also found that major histocompatibility complex class II molecule expression on DCs is regulated by TLR2 and MyD88 signaling but not by TLR9. Finally, lack of TLR9, TLR2, or MyD88 reduced the numbers of macrophages, epithelioid cells, and lymphocytes in
M
.
avium
-induced granulomas but only MyD88 deficiency affected the number of liver granulomas. In summary, our data demonstrated that the involvement of TLR9 in the control of
M
.
avium
infection is not related to the induction of Th1 responses.