Innovative Reversed-Phase Chromatography Platform Approach for the Fast and Accurate Characterization of Membrane Vesicles' Protein Patterns

Outer membrane vesicles (OMVs) have been widely explored to develop vaccine candidates for bacterial pathogens due to their ability to combine adjuvant properties with immunogenic activity. OMV expresses a variety of proteins and carbohydrate antigens on their surfaces. For this reason, there is an analytical need to thoroughly characterize the species expressed at their surface: we here present a simple and accurate reversed-phase ultrahigh-performance liquid chromatography (RP-UPLC) method developed according to quality by design principles. This work provides an analytical alternative to the classical sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) characterization. The higher selectivity and sensitivity of the RP-UHPLC assay allow for the identification of additional protein species with respect to SDS-PAGE and facilitate its precise relative abundance quantification. According to validation results, the assay showed high accuracy, linearity, precision, repeatability, and a limit of quantification of 1% for less abundant proteins. This performance paves the way for improved production campaign consistency while also being analytically simple (no sample pretreatment required), making it suitable for routine quality control testing. In addition, the applicability of the assay to a wider range of vesicle classes (GMMA) was demonstrated.

Covid-19 pandemic and clinical activity stop: oral health study in a group of children

AIM

Public and private health services, which provide both preventive and health promotion interventions, were forced to suddenly stop their activities to limit the risk of infections during the pandemic emergency. Oral health administration, including that of children, was affected by these planned medical service closures, from both therapeutic and preventive perspectives. This study aims to analyse the consequences, at the oral cavity level, of failures to treat patients of childhood age, considering the impact of carious pathology on quality of life and incorrect eating and oral hygiene habits, which may occur in this age group.

METHODS

This is a cross-sectional, single-center, observational study. One hundred patients from the Odontostomatological University Center (C.O.U.) of Perugia were randomly enrolled.

CONCLUSION

Oral health status of the examined sample is satisfactory overall, considering the clinic's interruption of treatments with the resulting long period of no follow-up and the emotional and economic stress generated by the pandemic condition for both the young patients and their caregivers.

A universal UHPLC-CAD platform for the quantification of polysaccharide antigens

Several glycoconjugate-based vaccines against bacterial infections have been developed and licensed for human use. Polysaccharide (PS) analysis and characterization is therefore critical to profile the composition of polysaccharide-based vaccines. For PS content quantification, the majority of Ultra High Performance Liquid Chromatography (UHPLC) methods rely on the detection of selective monosaccharides constituting the PS repeating unit, therefore requiring chemical cleavage and tailored development: only a few methods directly quantify the intact PS. The introduction of charged aerosol detector (CAD) technology has improved the response of polysaccharide analytes, offering greater sensitivity than other detector sources (e.g., ELSD). Herein, we report the development of a universal UHPLC-CAD method (UniQS) for the quantification and quality evaluation of polysaccharide antigens (e.g., Streptococcus Pneumoniae, Neisseria meningitidis and Staphylococcus aureus). This work laid the foundation for a universal UHPLC-CAD format that could play an important role in future vaccine research and development helping to reduce time, efforts, and costs.

Effects of an Educational Book on Paediatric Oral Health knowledge in a sample of Italian women

AIM

Parents and caregivers, particularly in Italy, often have limited knowledge about their children's oral health. The primary objective of the study is to evaluate the educational effectiveness of a book on nutrition and prevention of oral diseases entitled "Oral health of mother and child in the first 1000 days of life".

MATERIALS

The sample for this study was composed of 103 adult Italian women who were potential caregivers of one or more children (e.g., mothers, grandmothers, babysitters, and educators). The enrolled women completed a preliminary online survey which included questions about their socio-demographic characteristics and their knowledge on oral health in the first 1000 days of life of newborns (30 questions). Following the survey, they received the educational book. After reading it, the participants completed a second online survey with the same 30 questions, to measure any improvement in their knowledge.

CONCLUSION

It appears that our educational book about nutrition and prevention of oral diseases was effective in enhancing knowledge among the participants in our study. These findings suggest that this educational resource has the potential to be a valuable tool in preventing oral diseases in paediatric populations. However, further confirmation of these results should be obtained through randomised controlled trials.

Development of a New Solid-Phase Extraction Base Method for Free Saccharide Content Estimation of Meningococcal Conjugate Vaccines

GlaxoSmithKline (GSK) is currently developing a fully liquid presentation to ease the administration of the licensed quadrivalent conjugate vaccine (Menveo) against meningococcal serogroup A, C, W, and Y (MenACWY) infections. Herein, we report a new method for determining the free saccharide (FS) content of CRM₁₉₇-MenACWY conjugated antigens, with the aim of improving accuracy and reproducibility. Mathematical models have been used to support technical knowledge in reducing the need for experimental development. This results in an improved, faster, and platform-based technique for FS separation with one single pretreatment applicable to all antigens of the multivalent meningococcal vaccine.

Glycoconjugate content quantification to assess vaccine potency: A simplified approach

Several glycoconjugate vaccines have been licensed or are currently in clinical development to prevent bacterial infections. Here we report the development of a single analytical assay to quantify the conjugated saccharide content, as alternative to two separated total and free (unconjugated) saccharide assays used so far, for a quadrivalent conjugate vaccine containing meningococcal serogroup A polysaccharide (α-1,6-linked N-acetylmannosamine phosphate repeating unit partly O-acetylated at position C₃ or C₄) coupled with CRM₁₉₇ protein. The results confirm a high linear correlation among the two approaches (conjugated saccharide content vs. difference of total saccharide and free saccharide). Conjugated saccharide content estimation is therefore demonstrated to be a suitable method to monitor the product quality of vaccines containing meningococcal serogroup A conjugate antigen, in the final filled presentation as demonstrated here and potentially on the bulk conjugate before formulation.

Autism spectrum disorder and paediatric dentistry: A narrative overview of intervention strategy and introduction of an innovative technological intervention method

AIM

When treating patients with Autism Spectrum Disorder (ASD) the doctor-patient relationship can be very challenging. The dentist is often forced to work under general anaesthesia or conscious sedation. Children with ASD are patients with an increased risk of caries due to poor oral hygiene, a cariogenic diet and the use of xerostomal drugs. In this work therapeutic strategies used to treat this kind of patients are evaluated and a new method to treat children with ASD is presented in order to increase awareness about this condition in the dental field.

METHODS

The Atlas Center (a non-profit organisation in Peurgia, Italy) has developed a software, called paINTeraction, that allows these special children to immerse themselves in a virtual reality with the help of an operator. Through this system the child can explore the dental office (and all its sounds and noises) before the real dental visit, thus connecting to the dental professional, achieving greater compliance and reducing anxiety.

CONCLUSION

paINTeraction, with the use of digital technology tools, may be particularly well suited to introduce patients to the therapeutic environment, particularly in the dental setting.

Index of Orthodontic Treatment Need (IOTN) and distribution of malocclusion traits in a population of growing patients attending a public orthodontic service in Perugia (Italy)

AIM

Malocclusions are widespread all over the world with high prevalence values and represent a social vulnerability and health problem because of the important burden of orthodontic treatment for both families and the public health service. The Italian Ministry of Health identified the principles for priority setting in dental care, i.e. patients with IOTN (Index of Orthodontic Treatment Need) 4-5 and those in particular conditions of health or social vulnerability.

METHODS

A retrospective study was carried out to assess the IOTN and malocclusion in a population attending the public Orthodontic Health Service of Perugia (Italy) from September 2018 to February 2020. Medical charts, social income information, study models, photos and lateral cephalograms were examined to assess the orthodontic treatment need.

CONCLUSION

Orthodontic health service in Italy tends to have many patients on the waiting list, while the 72% of subject under orthodontic treatment are not part of the orthodontic priority (IOTN grade 4-5). This study suggests the heath system to guarantee a priority of need for orthodontic treatment for patients with health vulnerabilities.

Worldwide prevalence of malocclusion in the different stages of dentition: A systematic review and meta-analysis

AIM

The aim of this review is to quantify the prevalence and type of malocclusion among children and adolescents during the different stages of dentition worldwide.

MATERIALS AND METHODS

Recent studies (from 2009 to 2019), published in Medline, Web of Science and Embase and orthodontic text-books have been comprehensively reviewed herein. The methodological quality of the included studies was assessed using STROBE criteria.

RESULTS

After screening 450 records and analysing 284 relevant full-text publications, 77 studies were included in this review. A good degree of evidence was obtained due to the medium-high methodological quality level of included studies. The worldwide prevalence of malocclusion was 56% (95% CI: 11-99), without differences in gender. The highest prevalence was in Africa (81%) and Europe (72%), followed by America (53%) and Asia (48%). The malocclusion prevalence score did not change from primary to permanent dentition with a common score of 54%. Malocclusion traits such as Angle's classes, overjet, overbite, and asymmetrical midline shift essentially did not change their prevalence during different dentitions. Conversely, traits such as cross-bite and diastema reduced their prevalence during permanent dentition, while scissor-bite and dental crowding increased their scores.

CONCLUSION

The worldwide high prevalence of malocclusion and its early onset during childhood should induce policymakers as well as paediatric physicians and dentists to devise policies and adopt clinical strategies for preventing malocclusion since younger children's ages.

Sub-ablative laser irradiation to prevent acid demineralisation of dental enamel. A systematic review of literature reporting in vitro studies

AIM

Caries lesions begin with enamel acid demineralisation mediated by microorganisms. Lasers with sub-ablative energy might act as a prophylactic intervention to reinforce enamel against lesions caused by acid.

MATERIALS AND METHODS

A systematic review of the literature was performed evaluating only in vitro studies published from 2010 to 2018. The research was performed using the following databases: Medline, Embase and the Web Of Science. A further search was performed consulting the list of references of the included studies as well as book chapters which dealt with this topic.

RESULTS

A total of 347 records were retrieved and, after their evaluation, 36 studies were included. CO2 lasers were the most described and effective device in preventing acid demineralisation. This type of laser was unique in improving the already positive results obtained with fluoride-based interventions. Er,Cr:YSGG (with fluencies > 8.5J/cm2), diode and argon lasers also improved enamel acid resistance (p-values ranging from 0.05 to 0.001) producing similar effects with fluoride-based interventions. Regarding the sealant retention outcome, the Er:YAG laser was able to perform an enamel etching which was as effective as the traditional acid etching with the advantage of being easier and usually well accepted by low-compliant patients (i.e. younger children). Nd:YAG presented the worst results. The most common structural changes after the laser irradiation were water and carbonate reduction in the enamel combined with a phosphate and calcium enamel content increase. Moreover, the calcium/phosphate ratio was found to reach the 1.67 ideal ratio.

CONCLUSION

The in vitro studies that examined the prophylactic use of lasers for increasing enamel acid resistance presented interesting results that are enough to support a further in vivo experiment. This would entail the use of a clinical laser as an alternative or in combination with fluoride-based interventions.

Biological effects of resin monomers on oral cell populations: descriptive analysis of literature

AIM

Recently, the application of restorative materials containing metacrilate monomers in the conservative and paediatric dentistry has focused on the possible negative effects due to the use of these composites. In particular the release of monomers from reconstructions as a result of an insufficient polymerisation, can spread along the mucosal and dental tissues with potential immunological ed cytotoxic effects. Regarding to the importance of this issue, the aim of this study is to provide a descriptive review of the literature on potential local and systemic interactions of metacrylic and acrylic monomers with the immune system, both in vitro and in vivo.

RESULTS

The most highly used monomers in composite materials applied in conservative dentistry include: 2-hydroessietil- methacrylate (HEMA), triethylene glycol-dimethacrylate (TEGDMA), bisphenol A glycidyl-methacrylate (BisGMA) and urethane- dimethacrylate (UDMA). Different investigations have been performed for better understanding of the potential side effects of metacrylic monomers on immune system cells. Different factors such as cell population, exposure time and parameters more strictly connected to these materials, such as molecular weight, chemical composition and mechanical characteristics, seem to be directly involved in these reactions.

Correction to "NMR Assays for Estimating the O-Acetyl Content of Meningococcal Polysaccharide Serogroup A in Quadrivalent Conjugate Vaccine Formulation"

[This corrects the article DOI: 10.1021/acsomega.9b01678.].

NMR Assays for Estimating the O-Acetyl Content of Meningococcal Polysaccharide Serogroup A in Quadrivalent Conjugate Vaccine Formulation

The use of multivalent glycoconjugate vaccines has dramatically contributed to reduce the incidence of meningococcal infectious disease. The advanced structural characterization of polysaccharide conjugates leads to enhancements in the quality and control of the products. Here, we report a novel nuclear magnetic resonance (NMR) method to confirm the identity and structural conformity (e.g., O-acetyl content) of saccharide antigens that comprise a licensed tetravalent meningococcal serogroups A, C, W, and Y vaccine. For the first time, the NMR methodology is applied on a formulation (licensed vaccine) containing a large excess of excipient (i.e., sucrose) without analytical sample pretreatment. This work confirms the applicability of a rapid and easy NMR assay on a multivalent conjugate vaccine, which might be extended to other combination vaccines that are already licensed or in clinical development.

Dental fear/anxiety among children and adolescents. A systematic review

AIM

The aim of this paper was to review the published scientific literature to quantify the prevalence and mean score of dental fear/anxiety (DFA) in children/adolescents and its variation according to several variables.

MATERIALS AND METHODS

Cross- sectional and cohort studies published from 2000 to 2014, that measured DFA in children /adolescents (aged 0-19 years), in the general population, or visiting private or public dental services (general or pediatric) or attending school and kindergarten, were searched, with specific terms, in 3 electronic databases (Medline, Embase, Web Of Science). Primary data, collected with specific questionnaires of demonstrated reliability and/or validity, were extracted.

RESULTS

After screening 743 abstracts and evaluating 164 full-text publications, 36 articles were selected. Dental fear/anxiety prevalence rates were 12.2%, 10.0%, 12.2%,11.0% and 20.0% for the CFSS-DS, DAS, MDAS, DFS, and DFSS-SF scores, respectively. In the studies that used MCDAS Dental fear/prevalence rates varied from 13.3% to 29.3%. In the studies that used CFSS-DS ratings, the prevalence and the mean score of dental fear/anxiety was lower in Northern Europe than the remaining countries, the prevalence decreased with increasing age and the frequency was higher in females than males.

CONCLUSIONS

Dental fear/anxiety is a common problem in children/adolescents worldwide, therefore, new strategies to overcome this relevant children/adolescent condition should be encouraged.

Reliability and validity of the Italian versions of the Children's Fear Survey Schedule - Dental Subscale and the Modified Child Dental Anxiety Scale

AIM

Children's dental fear and anxiety (DFA) causes significant problems in clinical practice. The 15-item Children's Fear Survey Schedule - Dental Subscale (CFSS-DS) and the 8-item Modified Child Dental Anxiety Scale (MCDAS) are the most widely used measures of dental fear in children. The aim of this study is to examine the reliability and validity of the Italian versions of the CFSS-DS and MCDAS, also in comparison with a simple visual analogue scale (VAS).

MATERIALS AND METHODS

The CFSS-DS and MCDAS were translated into Italian by a consensus panel of experts and administered to 210 dental patients aged 4-11 years from three Italian Institutions. Internal reliability was assessed using the Cronbach's alpha correlation. A sub-sample of 60 children was selected for test-retest analysis. CFSS-DS and MCDAS, plus a VAS scale, rated both by children and parents, were validated using as gold standard the 4-item Frankl scale for behaviours assessed by dentists.

RESULTS

Mean CFSS-DS score was 30.8 (SD: 11.1) and mean MCDAS score was 17.9 (SD: 7.2), significantly higher among children aged 4-7 years and among children at their first dental visit. The alpha value for internal reliability was 0.90 (95%, CI= 0.88-0.92) for CFSS-DS and 0.87 (95% CI=0.85-0.90) for MCDAS. Both CFSS-DS and MCDAS showed good test-retest reliability (rsp= 0.80; p<0.001 for both scales). CFSS-DS and MCDAS predicted a Frankl score &#8804;2 (i.e., indicating children with an uncooperative behaviour) with a fair accuracy (AUC=0.69 and AUC=0.68, respectively). The VAS scale was more effective in predicting a negative behaviour (AUC=0.78). The scales self-reported by children were only slightly more accurate than those reported by parents.

CONCLUSION

The Italian versions of the CFSS-DS and MCDAS are valid and reliable tools for the assessment of dental fear in Italian children aged 4-11 years. A simple, one-item VAS, and dental fear and anxiety evaluation by parents may be valid and quick alternatives to multi-item indices to predict an uncooperative children behaviour.

Dental caries, parents educational level, family income and dental service attendance among children in Italy

AIM

The aim of this study was to verify whether socioeconomic determinants, such as parents' educational level, family income and dental service attendance by children, are associated with the presence of caries among an Italian population of children.

MATERIALS AND METHODS

An observational retrospective study was carried out in a population of children aged 4-14 years who visited the Paediatric Dentistry Department of the University of Perugia, Italy. Children were stratified according to familial socioeconomic level (father's and mother's educational level, family income) and dental service attendance of children. Age- and sex- adjusted odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated by means of multivariate logistic regression models.

RESULTS

A sample of 231 children (mean age 8.1 yrs, SD 2.6; 127 males, 104 females) was recruited. One hundred and sixty three (70.46%) children in the study had caries. Caries presence in children was higher in children where the mothers' educational level was lower (OR =6.1; 95% CI = 3.1 to 12.7), in children where the fathers' educational level was lower (OR =2.9; 95% CI =1.6 to 5.5) and in children with lower family income (OR = 9.9; 95% 95% CI = 5.1 to 20.1). No statistically significant difference were observed in terms of caries presence between the children who were visited at least once by a dentist and children who were not previously seen by a dental practitioner (OR = 0.8; 95% CI = 0.4 to 1.6).

CONCLUSION

Socioeconomic level was an important predictor of caries presence among children. Both low income and low parental educational level were related to an increased presence of caries, whereas previous dental visits experience did not affect caries presence in children.

Is pit and fissure sealing of buccal surfaces useful in reducing incidence of caries of first permanent molars?

AIM

The aim of the study was to establish whether caries prevalence on the buccal surfaces of first lower permanent molars (FLPMs) can be compared to those on the occlusal surfaces in order to justify the utility of extending pit and fissure sealing also to the extra-occlusal surfaces.

MATERIALS AND METHODS

Design: an observational study was carried out in the children population (n=779) aged ≤14 years (mean age 7.68, SD 3.53) that presented at the Paediatric Dentistry Department of the University of Perugia. In the study were included 460 patients, and absolute frequency (number) of FLMP occlusal and buccal caries, together with their ratio and their difference in percentage, were recorded and analysed. Moreover, FLMP buccal caries variation related to age, sex and parent's nationality were calculated.

RESULTS

Among the 460 children included (243 males) aged 5-14 years, 103 erupted FLPMs were analysed. Of their decayed surfaces (n=115), the occlusal surfaces were 62 (53.9%) and the buccal surfaces 53 (46.1%); the absolute frequency ratio was 1.17 and the percentage difference was 7.8%. The female gender was significantly related to buccal caries of FLPMs [OR = 2.66 (95% CI; 1.27-5.59; p=0.0096)] as was the age ranging between 10-14 years [OR = 2.73 (95% CI; 1.36-5.50; p =0.004)]. The parents nationality was not significantly related to buccal caries [Odds Ratio =1.47 (95% CI; 0.70-3.06; p = 09040)].

CONCLUSIONS

The similar caries susceptibility of buccal and occlusal surfaces of FLPMs stimulates further comparative studies about the usefulness of extending pit and fissure sealing to the buccal surfaces in addition to the occlusal prophylactic intervention, particularly with regard to the female sex and during the early eruption stages of these teeth.

Discovery of MK-5172, a Macrocyclic Hepatitis C Virus NS3/4a Protease Inhibitor

A new class of HCV NS3/4a protease inhibitors containing a P2 to P4 macrocyclic constraint was designed using a molecular modeling-derived strategy. Building on the profile of previous clinical compounds and exploring the P2 and linker regions of the series allowed for optimization of broad genotype and mutant enzyme potency, cellular activity, and rat liver exposure following oral dosing. These studies led to the identification of clinical candidate 15 (MK-5172), which is active against genotype 1-3 NS3/4a and clinically relevant mutant enzymes and has good plasma exposure and excellent liver exposure in multiple species.

DPP-IV-resistant, long-acting oxyntomodulin derivatives

Obesity is one of the major risk factors for type 2 diabetes, and the development of agents, that can simultaneously achieve glucose control and weight loss, is being actively pursued. Therapies based on peptide mimetics of the gut hormone glucagon-like peptide 1 (GLP-1) are rapidly gaining favor, due to their ability to increase insulin secretion in a strictly glucose-dependent manner, with little or no risk of hypoglycemia, and to their additional benefit of causing a modest, but durable weight loss. Oxyntomodulin (OXM), a 37-amino acid peptide hormone of the glucagon (GCG) family with dual agonistic activity on both the GLP-1 (GLP1R) and the GCG (GCGR) receptors, has been shown to reduce food intake and body weight in humans, with a lower incidence of treatment-associated nausea than GLP-1 mimetics. As for other peptide hormones, its clinical application is limited by the short circulatory half-life, a major component of which is cleavage by the enzyme dipeptidyl peptidase IV (DPP-IV). SAR studies on OXM, described herein, led to the identification of molecules resistant to DPP-IV degradation, with increased potency as compared to the natural hormone. Analogs derivatized with a cholesterol moiety display increased duration of action in vivo. Moreover, we identified a single substitution which can change the OXM pharmacological profile from a dual GLP1R/GCGR agonist to a selective GLP1R agonist. The latter finding enabled studies, described in detail in a separate study (Pocai A, Carrington PE, Adams JR, Wright M, Eiermann G, Zhu L, Du X, Petrov A, Lassman ME, Jiang G, Liu F, Miller C, Tota LM, Zhou G, Zhang X, Sountis MM, Santoprete A, Capitò E, Chicchi GG, Thornberry N, Bianchi E, Pessi A, Marsh DJ, SinhaRoy R. Glucagon-like peptide 1/glucagon receptor dual agonism reverses obesity in mice. Diabetes 2009; 58: 2258-2266), which highlight the potential of GLP1R/GCGR dual agonists as a potentially superior class of therapeutics over the pure GLP1R agonists currently in clinical use.

Enhancement of intestinal absorption of 2-methyl cytidine prodrugs

The purpose of this study was to investigate the in vivo absorption enhancement of a nucleoside (phosphoramidate prodrug of 2'-methyl-cytidine) anti-viral agent of proven efficacy by means of intestinal permeation enhancers. Natural nucleosides are hydrophilic molecules that do not rapidly penetrate cell membranes by diffusion and their absorption relies on specialized transporters. Therefore, the oral absorption of nucleoside prodrugs and the target organ concentration of the biologically active nucleotide can be limited due to poor permeation across the intestinal epithelium. In the present study, the specificity, concentration dependence, and effect of four classes of absorption promoters, i.e. fatty acids, steroidal detergents, mucoadhesive polymers, and secretory transport inhibitors, were evaluated in a rat in vivo model. Sodium caprate and alpha-tocopheryl-polyethyleneglycol-1000-succinate (TPGS) showed a significant effect in increasing liver concentration of nucleotide (5-fold). These results suggested that both excipients might be suited in a controlled release matrix for the synchronous release of the drug and absorption promoter directly to the site of absorption and highlights that the effect is strictly dependent on the absorption promoter dose. The feasibility of such a formulation approach in humans was evaluated with the aim of developing a solid dosage form for the peroral delivery of nucleosides and showed that these excipients do provide a potential valuable tool in pre-clinical efficacy studies to drive discovery programs forward.

An apoA-I mimetic peptide increases LCAT activity in mice through increasing HDL concentration

Lecithin cholesterol acyltransferase (LCAT) plays a key role in the reverse cholesterol transport (RCT) process by converting cholesterol to cholesteryl ester to form mature HDL particles, which in turn deliver cholesterol back to the liver for excretion and catabolism. HDL levels in human plasma are negatively correlated with cardiovascular risk and HDL functions are believed to be more important in atheroprotection. This study investigates whether and how D-4F, an apolipoprotein A-I (apoA-I) mimetic peptide, influences LCAT activity in the completion of the RCT process. We demonstrated that the apparent rate constant value of the LCAT enzyme reaction gives a measure of LCAT activity and determined the effects of free metals and a reducing agent on LCAT activity, showing an inhibition hierarchy of Zn(2+)>Mg(2+)>Ca(2+) and no inhibition with beta-mercaptoethanol up to 10 mM. We reconstituted nano-disc particles using apoA-I or D-4F with phospholipids. These particles elicited good activity in vitro in the stimulation of cholesterol efflux from macrophages through the ATP-binding cassette transporter A1 (ABCA1). With these particles we studied the LCAT activity and demonstrated that D-4F did not activate LCAT in vitro. Furthermore, we have done in vivo experiments with apoE-null mice and demonstrated that D-4F (20 mg/kg body weight, once daily subcutaneously) increased LCAT activity and HDL level as well as apoA-I concentration at 72 hours post initial dosing. Finally, we have established a correlation between HDL concentration and LCAT activity in the D-4F treated mice.

Ultrafast heme dynamics in ferrous versus ferric cytochrome c studied by time-resolved resonance Raman and transient absorption spectroscopy

Cytochrome c (Cyt c) is a heme protein involved in electron transfer and also in apoptosis. Its heme iron is bisaxially ligated to histidine and methionine side chains and both ferric and ferrous redox states are physiologically relevant, as well as a ligand exchange between internal residue and external diatomic molecule. The photodissociation of internal axial ligand was observed for several ferrous heme proteins including Cyt c, but no time-resolved studies have been reported on ferric Cyt c. To investigate how the oxidation state of the heme influences the primary photoprocesses, we performed a comprehensive comparative study on horse heart Cyt c by subpicosecond time-resolved resonance Raman and femtosecond transient absorption spectroscopy. We found that in ferric Cyt c, in contrast to ferrous Cyt c, the photodissociation of an internal ligand does not take place, and relaxation dynamics is dominated by vibrational cooling in the ground electronic state of the heme. The intermolecular vibrational energy transfer was found to proceed in a single phase with a temperature decay of approximately 7 ps in both ferric and ferrous Cyt c. For ferrous Cyt c, the instantaneous photodissociation of the methionine side chain from the heme iron is the dominant event, and its rebinding proceeds in two phases, with time constants of approximately 5 and approximately 16 ps. A mechanism of this process is discussed, and the difference in photoinduced coordination behavior between ferric and ferrous Cyt c is explained by an involvement of the excited electronic state coupled with conformational relaxation of the heme.

Molecular basis for nitric oxide dynamics and affinity with Alcaligenes xylosoxidans cytochrome c

The bacterial heme protein cytochrome ć from Alcaligenes xylosoxidans (AXCP) reacts with nitric oxide (NO) to form a 5-coordinate ferrous nitrosyl heme complex. The crystal structure of ferrous nitrosyl AXCP has previously revealed that NO is bound in an unprecedented manner on the proximal side of the heme. To understand how the protein structure of AXCP controls NO dynamics, we performed absorption and Raman time-resolved studies at the heme level as well as a molecular computational dynamics study at the entire protein structure level. We found that after NO dissociation from the heme iron, the structure of the proximal heme pocket of AXCP confines NO close to the iron so that an ultrafast (7 ps) and complete (99 +/- 1%) geminate rebinding occurs, whereas the proximal histidine does not rebind to the heme iron on the timescale of NO geminate rebinding. The distal side controls the initial NO binding, whereas the proximal heme pocket controls its release. These dynamic properties allow the trapping of NO within the protein core and represent an extreme behavior observed among heme proteins.

Photodissociation of heme distal methionine in ferrous cytochrome C revealed by subpicosecond time-resolved resonance Raman spectroscopy

Cytochrome c (cyt c) is an electron-transfer heme protein that also binds nitric oxide (NO). In resting cyt c, two endogenous ligands of the heme iron are histidine-18 (His) and methionine-80 (Met) side chains, and NO binding requires the cleavage of one of the axial bonds. Previous femtosecond transient absorption studies suggested the photolysis of either Fe-His or Fe-Met bonds. We aimed at unequivocally identifying the internal side chain that is photodissociated in ferrous cyt c and at monitoring heme structural dynamics, by means of time-resolved resonance Raman (TR3) spectroscopy with approximately 0.6 ps time resolution. The Fe-His stretching mode at 216 cm-1 has been observed in photoproduct TR3 spectra for the first time for a c-type heme. The same transient mode was observed for a model ferrous cyt c N-fragment (residues 1-56) ligated with two His in the resting state. Our TR3 data reveal that upon ferrous cyt c photoexcitation, (i) distal Met side chain is instantly released, producing a five-coordinated domed heme structure, (ii) proximal His side chain, coupled to the heme, exhibits distortion due to strain exerted by the protein, and (iii) alteration in heme-cysteine coupling takes place along with the relaxation of the protein-induced deformations of the heme macrocycle.

Activation of cytokine genes during primary and anamnestic immune response to inactivated c. albicans

Recent evidence suggests that after repeated stimulations with inactivated C. albicans (CA) cells, CD2F1 mice respond with a cytokine pattern typical of T-helper 1 (ThI) subset development. The purpose of this study was to analyse the sequence of immunological events which, soon after priming mice with CA, lead to the development of primary and anamnestic response. A comprehensive kinetics analysis of cytokine mRNA expression was performed by Northern blot assay, in peritoneal exudate cells (PEC), at different phases of immune response to CA: after priming (one i.p. injection of 2 x 10(7) CA cells mouse), during development of the primary immune response (five progressive CA i.p. injections over a 2-week period) and in the anamnestic response (CA booster 30 days after the primary response). In vitro assays were performed 2 and 24 hr after every CA stimulation. The response to CA priming was characterized by an early and high expression of interleukin-2 (IL-2) and IL-1 beta mRNAs At 24hr. IL-2 mRNA was still at a high level, while IL-1 beta had greatly decreased. A weak expression of IL-10 was only induced at 2 hr. whereas IL-12 p40 subunit, interferon-7 (IFN-7) IL-4 and IL-5 mRNAs were undetectable. In this phase no in vitro proliferative response of PEC to CA was observed, whereas a significant natural killer (NK) activity was induced. From the second CA injection, the IFN-7 mRNA was already induced at 2 hr. Its expression level increased progressively with the number of CA injections persisting up to 24 hr after the fifth stimulation. A progressive increase of IL-2 mRNA expression was also induced whereas IL-1 beta and IL-10 mRNAs were always transiently expressed at 2 hr at levels similar to those observed after the priming. IL-12 p40 subunit. IL-4 and IL-5 mRNAs were never detectable. The expression of this selected cytokine pattern typical of Thl response was correlated with the development of CA-specific T lymphocytes as confirmed by the in vitro proliferative response of CA-5d-induced PEC to CA. NK activity also increased progressively with the number of CA injections and after the fifth stimulation lymphokine-activated killer (LAK) activity was also induced. The anamnestic response to CA was characterized by a very quick induction of high levels of IL-2, II N-gamma and IL-1 beta mRNAs. IL-2 and IFN-gamma mRNAs remained high up to 24 hr while IL-1 beta mRNA decreased strongly. A weak, transient expression of IL-10 mRNA was induced at 2 hr whereas the IL-12 p40 subunit, IL-4 and IL-5 mRNAs were not detectable. The presence of CA-specific memory lymphocytes was confirmed by the in vitro specific proliferative response of PEC to CA. CA booster caused also a very rapid and high level of NK/LAK activation. In conclusion, these results indicate that CA is able to progressively trigger differential on of the Th1 subset which develops in the absence of IL-12, and that Th memory cells retain the same selected Th1 cytokine profile developed in the primary immune response.