Peri-operative management of a patient with an ectodermal dysplasia (Rapp-Hodgkin) syndrome

We present the case of a 41-year-old man with Rapp-Hodgkin syndrome who underwent nasal septum deviation surgery under general anaesthesia. This syndrome is rare, with approximately 70 cases reported worldwide. It is one of a group of ectodermal dysplasia syndromes and results from the aberrant development of ectoderm during fetal development. Some of the clinical features may affect anaesthetic management. The most important considerations are potentially difficult airway management, the need for meticulous temperature control, and the importance of skin protection. This case was uneventful, but as there are few case reports on the management of patients with ectodermal dysplasia syndromes undergoing anaesthesia this report contributes useful knowledge. The pathogenesis and clinical features of Rapp-Hodgkin syndrome and the anaesthetic management for this patient are described.

Can COVID-19 pandemic worsen previous neurological/psychiatric diseases?

Introduction

The SARS-CoV-2 pandemic has been affecting the world since January 2020. Although its pathogenesis is primarily directed to the respiratory tract, other organs may be affected, including the nervous system. It has also been shown that the social context (confinement, lack of treatment) has affected neurological patients during this period. The aim of the study it was to assess the subjective worsening of neurological/psychiatric diseases in the context of the SARS-Cov-2 pandemic.

Methods

Three groups of neurological/psychiatric patients were included: Patients who had symptomatic COVID-19 (n = 89), patients who had asymptomatic COVID-19 (n = 40), and a control group (n = 47), consisting of neurological/psychiatric patients without a history of SARS-Cov-2 infection.

Results

30.7% of the included individuals considered that their basal pathology had worsened during the study period. This feeling was significantly more frequent (P = 0.01) in patients with symptomatic COVID-19 (39.3%) than in patients of the other 2 groups (21.8%). Worsening was not related to the severity of COVID-19. The neurological conditions that significantly worsened after COVID-19, comparing symptomatic COVID-19 with the other 2 groups, were demyelinating and degenerative diseases.

Conclusions

These results confirmed the impact of the SARS-Cov-2 pandemic on patients with neurological/psychiatric diseases. Confinement, lack of medical care, and the threat of diagnosis are surely contributing factors. Although the finding of a higher frequency of worsening in symptomatic COVID-19 patients may be related to greater anxiety/depression in this group of patients, we cannot exclude the role of direct affectation of the nervous system by the virus or damage due to neuroinflammation.

Development of an intervention to manage knee osteoarthritis risk and symptoms following anterior cruciate ligament injury

INTRODUCTION

Anterior cruciate ligament (ACL) injury is a risk factor for developing knee osteoarthritis (OA). We developed an intervention to support people manage risk factors for OA.

METHODS

We conducted one-on-one interviews with 20 individuals with OA symptoms 6-15 years post ACL injury and used a nominal group process during a workshop with 40 patients and healthcare professionals (HCPs) to elicit information on the intervention content and delivery characteristics (timing, HCPs, and methods). Interview data were analyzed using content analysis. Nominal group ideas with importance ratings ≥5 of 7 met criteria for inclusion. Results were integrated, considering similarities and differences.

RESULTS

Eight content categories were identified: 1. understanding knee injury and expectations about recovery; 2. understanding OA risk; 3. understanding OA signs and symptoms; 4. managing OA risk; 5. managing knee OA symptoms; 6. information for influencers; 7. credible sources; and, 8. updates on new evidence and treatments. Delivery timing reflected a lifespan approach from time of injury through symptomatic knee OA management. Although multiple media for delivery were identified, introductory face-to-face discussions and opportunity for re-accessing HCPs were critical. All HCPs who treat people with ACL should be familiar with and able to deliver the intervention.

CONCLUSIONS

This co-development approach identified that an intervention to support people with ACL injury to limit and manage knee OA requires content embedded within an easily accessible, multi-media delivery model with capacity for check-back with HCPs that is appealing to different age groups and personal preferences over the lifespan post injury.

Early Cerebrovascular Ultrasonography as a Predictor of Hemorrhagic Transformation After Thrombectomy

OBJECTIVES

To determine the predictive value of early transcranial color-coded sonography (TCCS) for intracranial hemorrhage (ICH) in patients with large artery occlusion (LAO) stroke of carotid circulation, who were submitted to endovascular therapy (EVT) with successful reperfusion.

MATERIALS AND METHODS

Retrospective study evaluating a cohort of consecutive stroke patients with LAO of the carotid circulation that were recanalyzed with EVT. We measured angle-corrected peak systolic velocities, end-diastolic velocities and mean flow velocities (PSV, EDV and MFV) of the symptomatic and asymptomatic middle cerebral artery (MCA). The ratio between MFV of the symptomatic MCA and MFV of the asymptomatic MCA (MCA-Ra) was calculated. Parenchymal hematoma in the 24 hours control CT was considered as ICH. Univariate associations and multivariate analyses were used to identify early independent predictors for ICH among TCCS findings.

RESULTS

We included 234 patients, mean age 72.5 (SD 12.6) years, 52.1% male. The mean time between recanalization and TCCS was 12.3 hours (range 3-22). Patients who developed postinterventional ICH showed a higher MCA-Ra (1.02 ± 0.26 vs 1.16 ± 0,21, p = 0.036). In multivariate analysis, only higher MCA-Ra remained independently associated with postinterventional ICH (OR: 6.778, 95%CI: 1.152-39.892, p = 0.034). A value of MCA-Ra ≥ 1,05 was associated with ICH, showing a sensitivity of 81.3% and a specificity of 65.9%; the AUC based of the ROC analysis was 0.688 (95% CI 0.570-0.806).

CONCLUSION

TCCS performed within the first 24 hours after stroke onset can help to predict hemorrhagic transformation in patients with LAO.

Disaccharide anthocyanin delphinidin 3-O-sambubioside from Hibiscus sabdariffa L.: Candida antarctica lipase B-catalyzed fatty acid acylation and study of its color properties

Enzymatic lipophilization is an important process to extend the use of anthocyanins in lipidic media. In this work delphinidin 3-O-sambubioside (Dp3sam) isolated from Hibiscus sabdariffa L. flower was esterified with octanoic acid using Candida antarctica lipase B. The physical-chemical properties of the new lipophilic pigment were studied by UV-vis spectroscopy. Dp3sam with chloride, acetate and formate as counter ions were employed to study the lipophilization reaction. The hydrolysis of the reagent was avoided with a formate counter ion and the expected product was achieved with a noteworthy change of solubility. 1D and 2D NMR characterization of Dp3sam-C8 confirmed that the lipophilization took place at the primary alcohol of the glucoside moiety. Overall, the Dp3sam-C8 ester presents a stabilization of the quinoidal base (blue color) at neutral or moderate alkaline pH, which foresees a potential use of this pigment as a broad kind of industries on lipo-soluble formulations.

Evidence for Succession and Putative Metabolic Roles of Fungi and Bacteria in the Farming Mutualism of the Ambrosia Beetle Xyleborus affinis

The bacterial and fungal community involved in ambrosia beetle fungiculture remains poorly studied compared to the famous fungus-farming ants and termites. Here we studied microbial community dynamics of laboratory nests, adults, and brood during the life cycle of the sugarcane shot hole borer, Xyleborus affinis We identified a total of 40 fungal and 428 bacterial operational taxonomic units (OTUs), from which only five fungi (a Raffaelea fungus and four ascomycete yeasts) and four bacterial genera (Stenotrophomonas, Enterobacter, Burkholderia, and Ochrobactrum) can be considered the core community playing the most relevant symbiotic role. Both the fungal and bacterial populations varied significantly during the beetle's life cycle. While the ascomycete yeasts were the main colonizers of the gallery early on, the Raffaelea and other filamentous fungi appeared after day 10, at the time when larval hatching happened. Regarding bacteria, Stenotrophomonas and Enterobacter dominated overall but decreased in foundresses and brood with age. Finally, inferred analyses of the putative metabolic capabilities of the bacterial microbiome revealed that they are involved in (i) degradation of fungal and plant polymers, (ii) fixation of atmospheric nitrogen, and (iii) essential amino acid, cofactor, and vitamin provisioning. Overall, our results suggest that yeasts and bacteria are more strongly involved in supporting the beetle-fungus farming symbiosis than previously thought.IMPORTANCE Ambrosia beetles farm their own food fungi within tunnel systems in wood and are among the three insect lineages performing agriculture (the others are fungus-farming ants and termites). In ambrosia beetles, primary ambrosia fungus cultivars have been regarded essential, whereas other microbes have been more or less ignored. Our KEGG analyses suggest so far unknown roles of yeasts and bacterial symbionts, by preparing the tunnel walls for the primary ambrosia fungi. This preparation includes enzymatic degradation of wood, essential amino acid production, and nitrogen fixation. The latter is especially exciting because if it turns out to be present in vivo in ambrosia beetles, all farming animals (including humans) are dependent on atmospheric nitrogen fertilization of their crops. As previous internal transcribed spacer (ITS) metabarcoding approaches failed on covering the primary ambrosia fungi, our 18S metabarcoding approach can also serve as a template for future studies on the ambrosia beetle-fungus symbiosis.

Ketoprofen-loaded rose hip oil nanocapsules attenuate chronic inflammatory response in a pre-clinical trial in mice

This study aimed to develop nanocapsules containing ketoprofen using rose hip oil (Keto-NC) as oil core, and to evaluate their anti-inflammatory activity in acute and chronic ear edema models in mice. Physicochemical characterization, drug release, photostability and cytotoxicity assays were performed for the developed Keto-NC formulations and compared to ketoprofen-loaded nanocapsules using medium chain triglycerides as oil core (Keto-MCT-NC). Anti-inflammatory activity of orally delivered KP (Ketoprofen-free; 10 mg.kg^-1) or Keto-NC (2.5; 5; 10 mg.kg^-1) was assessed in mouse acute and chronic ear edema induced by croton oil (CO). Edema histological characteristics were determined by H&E stain, and redox parameters were analyzed in blood plasma and erythrocytes. Keto-MCT-NC and Keto-NC did not exhibit differences regarding physicochemical parameters, including size diameters, polydispersity index, pH, Ketoprofen content, and encapsulation efficiency. However, Keto-NC, which contains rose hip oil as lipid core, decreased drug photodegradation under UVC radiation when compared to Keto-MCT-NC. KP or Keto-NC were not cytotoxic to keratinocyte cultures and produced equal edema inhibition in the acute protocol. Conversely, in the chronic protocol, Keto-NC was more effective in reducing edema (~60-70% on 7-9th days of treatment) when compared to KP (~40% on 8-9th days of treatment). This result was confirmed by histological analysis, which indicated reduction of edema and inflammatory infiltrate. A sub-therapeutic dose of Keto-NC (5 mg.kg^-1) significantly reduced edema when compared to control. Finally, KP and Keto-NC exhibited similar effects on redox parameters, suggesting that the advantages associated with Ketoprofen nanoencapsulation did not involve oxidative stress pathways. The results showed that Keto-NC was more efficient than KP in reducing chronic inflammation. These data may be important for the development of strategies aiming treatment of chronic inflammatory diseases with fewer adverse effects.

Impact of Rearing Conditions on the Ambrosia Beetle's Microbiome

Ambrosia beetles, along with termites and leafcutter ants, are the only fungus-farming lineages within the tree of life. Bacteria harbored by ambrosia beetles may play an essential role in the nutritional symbiotic interactions with their associated fungi; however, little is known about the impact of rearing conditions on the microbiota of ambrosia beetles. We have used culture-independent methods to explore the effect of rearing conditions on the microbiome associated with Xyleborus affinis, Xyleborus bispinatus, and Xyleborus volvulus, evaluating different media in laboratory-controlled conditions and comparing wild and laboratory conditions. Our results revealed that rearing conditions affected the fungal and bacterial microbiome structure and had a strong influence on bacterial metabolic capacities. We propose that the rearing conditions influence the ambrosia-associated fungal and bacterial communities. Furthermore, bacterial microbiome flexibility may help beetles adapt to different substrates.

Pharmacokinetics of table and Port red wine anthocyanins: a crossover trial in healthy men

This study was designed to evaluate the pharmacokinetics of Port and table red wine anthocyanins in healthy men. Volunteers were recruited to drink 250 mL of a table red wine (221 mg of anthocyanins) and 150 mL of young Port red wine (49 mg of anthocyanins). Venous blood was collected from participants at 0, 15, 30, 60 and 120 min after wine ingestion. Urine samples were collected at baseline and at 120 min. Anthocyanins and anthocyanin metabolites in plasma and urine samples were quantified by HPLC-DAD and tentatively identified by LC-MS. Red wine anthocyanins were detected in their intact forms in both plasma and urine samples, but the glucuronylated metabolites of peonidin and malvidin (PnGlucr and MvGlucr) were the two main derivatives detected after both red wine consumptions. For the first time, and supported by the synthesis of Mv3Glucr, the main pathway followed by Mv3glc after absorption was described and involves anthocyanidin conjugation with glucuronic acid after glucose removal. Despite the lower total content of anthocyanins ingested when volunteers drank Port wine, no differences were observed in the plasma C_max of MvGlucr and PnGlucr after table and Port red wine consumption. The relative bioavailability of anthocyanins in Port wine was 96.58 ± 5.74%, compared to the anthocyanins present in red wine. In conclusion, both Port and table red wines are good sources of bioavailable anthocyanins.

Selection by mating competitiveness improves the performance of Anastrepha ludens males of the genetic sexing strain Tapachula-7

The sexual performance of Anastrepha ludens males of the Tapachula-7 genetic sexing strain, produced via selection based on mating success, was compared with that of males produced without selection in competition with wild males. Mating competition, development time, survival, mass-rearing quality parameters and pheromone production were compared. The results showed that selection based on mating competitiveness significantly improved the sexual performance of offspring. Development time, survival of larvae, pupae and adults, and weights of larvae and pupae increased with each selection cycle. Differences in the relative quantity of the pheromone compounds (Z)-3-nonenol and anastrephin were observed when comparing the parental males with the F4 and wild males. The implications of this colony management method on the sterile insect technique are discussed.

The effect of antibacterial and non-antibacterial compounds alone or associated with antifugals upon fungi

During the last 30 years the incidence of fungal infections has increased dramatically. While the antifungal therapeutic options available are somewhat reduced, most pathogenic microorganisms have an incredible capacity to mutate and acquire resistance. In addition, multiple drugs are often required concomitantly to manage clinically complex disorders. The combination of antibiotics or other compounds with antifungal drugs, simultaneously or sequentially, is commonly adopted in clinical practice, although without a full knowledge of the consequences. Thus, the role of combined therapy and the effect of antibiotics upon fungal growth promotion need to be critically evaluated and understood in order to avoid undesirable drug interactions. With this review we intend discuss the studies that report about antibiotics inhibiting fungal growth, as well as studies describing the synergistic effect of the combined therapy, i.e., associations between antibiotics or other compounds with antifungal drugs. Alternative therapeutic protocols for fungal disease could be designed, taking advantage of such drug combinations. Critical revision of previously published data is crucial in order to define future research strategies.

First Report of Xanthomonas campestris pv. raphani Causing Leaf Spot Disease of Brassica oleracea in Portugal

Representing over 25% of the vegetable production, Brassicaceae crops are very important for Portuguese agriculture. Xanthomonas campestris pv. raphani (Xcr) was first described as the causative agent of a leaf spot disease affecting radish and turnip (4). Despite its ability to infect Solanaceae hosts upon inoculation, this pathogen affects mostly Brassicaceae plants. Typical symptoms include circular dark spots that become lighter and are occasionally surrounded by a chlorotic halo. In severely affected leaves, spots were not limited by the veins and coalesced into irregular shapes that perforated the leaves, rendering the plants unsuitable for marketing. In the early 2000s, several isolates causing leaf spots on Brassica oleracea varieties (cauliflower, white cabbage, savoy cabbage, and tronchuda cabbage) were collected in Sintra, near Lisbon. The isolates, identified as putative X. campestris (Xc), formed typical yellow mucoid and convex colonies when grown on YDC medium. Biochemical characterization (2) showed their ability to produce levan and hydrolyze starch and esculin. Isolates were also able to use celobiose, trehalose, glucose, mannose, raffinose, and sucrose. Furthermore, the isolates were oxidase negative and were unable to hydrolyze arginine and to use rhamnose, indol, inositol, and sorbitol, confirming them as Xc. The expected 619-bp amplicon was obtained for all isolates, after PCR using primers DLH120/DLH125 (1). Koch's postulates were fulfilled through pathogenicity tests on B. oleracea cv. Wirosa and Raphanus sativus, hosts susceptible to Xcr as well as to X. campestris pv. campestris (Xcc). Inoculations on B. carinata (Assession No. PI199947) and Solanum lycopersicum, hosts susceptible only to Xcr, were performed to confirm pathovar identification (2). Four plants of each host were inoculated with each isolate by spraying bacterial water suspensions (OD₆₀₀ = 0.1) onto leaf surfaces. Positive and negative controls were performed using Xcc type strain (CFBP 5241) and sterile distilled water, respectively. Plants were kept 15 days with 16-h light and 8-h dark photoperiods at 24 and 18°C, respectively, at RH >80% and checked daily for symptom development. Leaf spots typical of Xcr were observed for all isolates on all hosts 5 days after inoculation. All isolates were recovered after re-isolation from inoculated plants, retaining their initial features. Negative control plants showed no symptoms, while CFBP 5241 caused V-shaped lesions, typical of Xcc, on B. oleracea cv. Wirosa and R. sativus. Further confirmation of the identification was attained by partial sequencing of the gyrB gene, using primers X.gyr.fsp.s1/X.gyr.rsp3 (3). Sequences from four isolates (CPBF 143, Genbank KM094906; CPBF 207, GenBank KM094907; CPBF 209, GenBank GU596416; and CPBF 1171, GenBank GU596419) were compared by nucleotide blast at NCBI and displayed higher levels of DNA similarity (>98%) to NCPPB 1946, the type strain for Xcr, than to NCPPB 528, the type strain for Xcc. The polyphasic approach combining phenotypic and genomic data confirmed the presence of X. campestris pv. raphani in Portugal for the first time. References: (1) T. Berg et al. Plant Pathol. 54: 416, 2005. (2) R. Lelliot and D. Stead. Methods for the Diagnosis of Bacterial Diseases of Plants. Blackwell Scientific Publications, Oxford, England, 1987. (3) N. Parkinson et al. Int. J. Syst. Evol. Microbiol. 57:2881, 2007. (4) H. White. Phytopathology 20:653, 1930.

Relationship between phenol degradation efficiency and microbial community structure in an anaerobic SBR

Phenol is a common wastewater contaminant from various industrial processes, including petrochemical refineries and chemical compounds production. Due to its toxicity to microbial activity, it can affect the efficiency of biological wastewater treatment processes. In this study, the efficiency of an Anaerobic Sequencing Batch Reactor (ASBR) fed with increasing phenol concentrations (from 120 to 1200 mg L(-1)) was assessed and the relationship between phenol degradation capacity and the microbial community structure was evaluated. Up to a feeding concentration of 800 mg L(-1), the initial degradation rate steadily increased with phenol concentration (up to 180 mg L(-1) d(-1)) and the elimination capacity remained relatively constant around 27 mg phenol removed∙gVSS(-1) d(-1). Operation at higher concentrations (1200 mg L(-1)) resulted in a still efficient but slower process: the elimination capacity and the initial degradation rate decreased to, respectively, 11 mg phenol removed∙gVSS(-1) d(-1) and 154 mg L(-1) d(-1). As revealed by Denaturing Gradient Gel Electrophoresis (DGGE) analysis, the increase of phenol concentration induced level-dependent structural modifications of the community composition which suggest an adaptation process. The increase of phenol concentration from 120 to 800 mg L(-1) had little effect on the community structure, while it involved drastic structural changes when increasing from 800 to 1200 mg L(-1), including a strong community structure shift, suggesting the specialization of the community through the emergence and selection of most adapted phylotypes. The thresholds of structural and functional disturbances were similar, suggesting the correlation of degradation performance and community structure. The Canonical Correspondence Analysis (CCA) confirmed that the ASBR functional performance was essentially driven by specific community traits. Under the highest feeding concentration, the most abundant ribotype probably involved in successful phenol degradation at 1200 mg L(-1) was affiliated to the Anaerolineaceae family.

Non-inferiority cancer clinical trials: scope and purposes underlying their design

BACKGROUND

Non-inferiority clinical trials (NIFCTs) aim to demonstrate that the experimental therapy has advantages over the standard of care, with acceptable loss of efficacy. We evaluated the purposes underlying the selection of a non-inferiority design in oncology and the size of their non-inferiority margins (NIFm's).

PATIENTS AND METHODS

All NIFCTs of cancer-directed therapies and supportive care agents published in a 10-year period were eligible. Two investigators extracted the data and independently classified the trials by their purpose to choose a non-inferiority design.

RESULTS

Seventy-five were included: 43% received funds from industry, overall survival was the most common primary end point and 73% reported positive results. The most frequent purposes underlying the selection of a non-inferiority design were to test more conveniently administered schedules and/or less toxic treatments. In 13 (17%) trials, a clear purpose was not identified. Among the trials that reported a pre-specified NIFm, the median value was 12.5% (range 4%-25%) for trials with binary primary end points and Hazard Ratio of 1.25 (range 1.10-1.50) for trials that used time-to-event primary outcomes.

CONCLUSION

Cancer NIFCT harbor serious methodological and ethical issues. Many use large NIFm and nearly one-fifth did not state a clear purpose for selecting a non-inferiority design.

Dynamics of metastable β-hairpin structures in the folding nucleus of amyloid β-protein

The amyloid β-protein (Aβ), which is present predominately as a 40- or 42-residue peptide, is postulated to play a seminal role in the pathogenesis of Alzheimer's disease (AD). Folding of the Aβ(21-30) decapeptide region is a critical step in the aggregation of Aβ. We report results of constant temperature all-atom molecular dynamics simulations in explicit water of the dynamics of monomeric Aβ(21-30) and its Dutch [Glu22Gln], Arctic [Glu22Gly], and Iowa [Asp23Asn] isoforms that are associated with familial forms of cerebral amyloid angiopathy and AD. The simulations revealed a variety of loop conformers that exhibited a hydrogen bond network involving the Asp23 and Ser26 amino acids. A population of conformers, not part of the loop population, was found to form metastable β-hairpin structures with the highest probability in the Iowa mutant. At least three β-hairpin structures were found that differed in their hydrogen bonding register, average number of backbone hydrogen bonds, and lifetimes. Analysis revealed that the Dutch mutant had the longest β-hairpin lifetime (≥500 ns), closely followed by the Iowa mutant (≈500 ns). Aβ(21-30) and the Arctic mutant had significantly lower lifetimes (≈200 ns). Hydrophobic packing of side chains was responsible for enhanced β-hairpin lifetimes in the Dutch and Iowa mutants, whereas lifetimes in Aβ(21-30) and its Arctic mutant were influenced by the backbone hydrogen bonding. The data suggest that prolonged β-hairpin lifetimes may impact peptide pathogenicity in vivo.

Structural basis for Aβ1–42 toxicity inhibition by Aβ C-terminal fragments: discrete molecular dynamics study

Amyloid β-protein (Aβ) is central to the pathology of Alzheimer's disease. Of the two predominant Aβ alloforms, Aβ(1-40) and Aβ(1-42), the latter forms more toxic oligomers. C-terminal fragments (CTFs) of Aβ were recently shown to inhibit Aβ(1-42) toxicity in vitro. Here, we studied Aβ(1-42) assembly in the presence of three effective CTF inhibitors and an ineffective fragment, Aβ(21-30). Using a discrete molecular dynamics approach that recently was shown to capture key differences between Aβ(1-40) and Aβ(1-42) oligomerization, we compared Aβ(1-42) oligomer formation in the absence and presence of CTFs or Aβ(21-30) and identified structural elements of Aβ(1-42) that correlated with Aβ(1-42) toxicity. CTFs co-assembled with Aβ(1-42) into large heterooligomers containing multiple Aβ(1-42) and inhibitor fragments. In contrast, Aβ(21-30) co-assembled with Aβ(1-42) into heterooligomers containing mostly a single Aβ(1-42) and multiple Aβ(21-30) fragments. The CTFs, but not Aβ(21-30), decreased the β-strand propensity of Aβ(1-42) in a concentration-dependent manner. CTFs and Aβ(21-30) had a high binding propensity to the hydrophobic regions of Aβ(1-42), but only CTFs were found to bind the Aβ(1-42) region A2-F4. Consequently, only CTFs but not Aβ(21-30) reduced the solvent accessibility of Aβ(1-42) in region D1-R5. The reduced solvent accessibility of Aβ(1-42) in the presence of CTFs was comparable to the solvent accessibility of Aβ(1-40) oligomers formed in the absence of Aβ fragments. These findings suggest that region D1-R5, which was more exposed to the solvent in Aβ(1-42) than in Aβ(1-40) oligomers, is involved in mediating Aβ(1-42) oligomer neurotoxicity.

First Report of Bacterial Speck of Tomato Caused by Pseudomonas syringae pv. tomato Race 1 in Portugal

Protected and open field tomato crops are economically important for Portuguese agriculture. In 1983, Pseudomonas syringae pv. tomato (Okabe, 1933) Young, Dye & Wilkie, 1978 was first reported affecting protected crops (3) and then later under open field conditions (1). In the 2009 spring/summer season, several outbreaks of bacterial speck of tomato showing an unusual degree of severity were observed in open fields from the Tagus Valley Region. Typical symptoms included necrotic specks surrounded by a yellow halo on younger and older leaves with losses higher than 60% due to the heavy floral bud abortion. Abnormal lesions on the stems, as well as on the petioles and fruits, together with reduced growth of the entire plant, which is normally uncommon, were frequently observed in affected plants from distinct tomato cultivars (H-9665, H-9776, and CDX 255), two of them carrying the Pto resistance gene. Samples collected from different fields and cultivars were observed and used for isolation of the causal agent on King's medium B. The isolates were characterized (2) and Koch's postulates were fulfilled by carrying out pathogenicity tests. Ten plants from three commercial cultivars carrying the Pto resistance gene (CXD 255, Defender F1, and H-9775) were inoculated by spraying bacterial water suspensions (10⁸ CFU ml^-1) and kept under environmental conditions favorable for disease development. Positive and negative controls were also performed using P. syringae pv. tomato type strain (CFBP 2212T; race 0) and sterile distilled water, respectively. Cultural and biochemical characterization of the isolates showed their ability to produce levan, use sucrose, and induce a hypersensitivity reaction on tobacco leaves. Moreover, the isolates were oxidase negative, did not hydrolyze arginine nor produce soft rot on potato slices, and did not use erythritol as well as dl-lactate, identifying them as P. syringae pv. tomato. Typical and severe bacterial speck symptoms were produced in the Pto resistant tomato plants 4 days after inoculation and the isolates could be recovered after reisolation. Negative control plants showed no disease symptoms and CFBP 2212 was unable to produce typical lesions, except for a few in the older leaves. Altogether these results pointed to P. syringae pv. tomato race 1 as the disease causative agent. Further confirmation was achieved by partial sequencing of the rpoD gene using primers PsrpoD FNP1 and PsrpoDnprpcr1 (4). rpoD sequences, obtained from two isolates (CPBF 1288, GenBank HM368535; CPBF 1290, GenBank HM368537), were compared by nucleotide BLAST at NCBI displaying a 100% level of DNA similarity with strain Pto T1 belonging to P. syringae pv. tomato race 1. To our knowledge, this is the first report of the occurrence of Pseudomonas syringae pv. tomato race 1 in Portugal. References: (1) L. Cruz et al. ATTI Giornate Fitopatol, 2:399, 1992. (2) R. Lelliott and D. Stead. Methods for the Diagnosis of Bacterial Diseases of Plants. Blackwell Scientific Publications, Oxford, 1987. (3) H. Oliveira and J. Santa-Marta. Pseudomonas syringae pv. tomato (Okabe, 1933) Young, Dye & Wilkie, 1978. Uma nova bacteriose do tomateiro em Portugal. Publicação do Laboratório de Patologia Vegetal "Veríssimo de Almeida", 1983. (4). S. Sarkar et al. Genetics 174:1041, 2006.

Elucidation of amyloid beta-protein oligomerization mechanisms: discrete molecular dynamics study

Oligomers of amyloid beta-protein (Abeta) play a central role in the pathology of Alzheimer's disease. Of the two predominant Abeta alloforms, Abeta(1-40) and Abeta(1-42), Abeta(1-42) is more strongly implicated in the disease. We elucidated the structural characteristics of oligomers of Abeta(1-40) and Abeta(1-42) and their Arctic mutants, [E22G]Abeta(1-40) and [E22G]Abeta(1-42). We simulated oligomer formation using discrete molecular dynamics (DMD) with a four-bead protein model, backbone hydrogen bonding, and residue-specific interactions due to effective hydropathy and charge. For all four peptides under study, we derived the characteristic oligomer size distributions that were in agreement with prior experimental findings. Unlike Abeta(1-40), Abeta(1-42) had a high propensity to form paranuclei (pentameric or hexameric) structures that could self-associate into higher-order oligomers. Neither of the Arctic mutants formed higher-order oligomers, but [E22G]Abeta(1-40) formed paranuclei with a similar propensity to that of Abeta(1-42). Whereas the best agreement with the experimental data was obtained when the charged residues were modeled as solely hydrophilic, further assembly from spherical oligomers into elongated protofibrils was induced by nonzero electrostatic interactions among the charged residues. Structural analysis revealed that the C-terminal region played a dominant role in Abeta(1-42) oligomer formation whereas Abeta(1-40) oligomerization was primarily driven by intermolecular interactions among the central hydrophobic regions. The N-terminal region A2-F4 played a prominent role in Abeta(1-40) oligomerization but did not contribute to the oligomerization of Abeta(1-42) or the Arctic mutants. The oligomer structure of both Arctic peptides resembled Abeta(1-42) more than Abeta(1-40), consistent with their potentially more toxic nature.

Prevalence of aeroallergen sensitization and increased exhaled nitric oxide values in schoolchildren of different socioeconomic status

BACKGROUND

Screening for allergic diseases allows an early diagnosis to be made, thus reducing socioeconomic burden and enhancing quality of life. We determined the prevalence of elevated exhaled nitric oxide (eNO) levels and sensitization to common airborne allergens in schoolchildren from different socioeconomic backgrounds.

MATERIAL AND METHODS

The study population comprised 271 children (136 boys) aged between 8 and 12 years in whom we applied skin prick tests and determined eNO levels.

RESULTS

Thirty-five percent of the children were identified as atopic. There was a significantly higher prevalence of atopy in boys (43% vs. 27%). Among the children with a high socioeconomic status, 37% were atopic, compared with 30% of those with a low socioeconomic status. We observed a significantly lower prevalence of pollen sensitization in children of lower socioeconomic status (10% vs. 20%). In the atopic group, 51% had elevated eNO levels, while in the nonatopic group this value was 4%. The mean (SD) eNO level was 33.4 (26.6) ppb in the atopic group and 11.9 (6.4) ppb in the nonatopic group. No differences were found for eNO values in terms of gender or socioeconomic status.

CONCLUSIONS

Our results emphasize the high prevalence of atopy in our population and suggest that determination of eNO levels could help to provide an early diagnosis. We also observed the following: (a) a significant difference in mean eNO values between atopic and nonatopic children; (b) a significantly lower prevalence of pollen sensitization in children of lower socioeconomic status; and (c) a higher prevalence of atopy in boys.

Immediate hypersensitivity to penicillins with negative skin tests--the value of specific IgE

The determination of specific IgE in patients with history of penicillins hypersensitivity is simple, safe and widely available. The positive and negative predictive values of this determination, however, are not yet established. In order to evaluate them, we performed specific IgE determination and diagnostic drug challenges in a group of 22 patients with a clear history of immediate penicillins hypersensitivity but negative skin tests. In this sample, the positive and negative predictive values were 29% and 87%, respectively. This seems to indicate that a positive specific IgE is not enough to confirm the diagnosis, and further study is necessary.

Work up of patients with history of beta-lactam hypersensitivity

INTRODUCTION

Beta-lactam antibiotics are the most frequent cause of antibiotic hypersensitivity reactions. The study of all cases of suspected beta-lactam hypersensitivity is highly important, to avoid the use of less efficient or more expensive alternatives, for fear of a reaction.

MATERIALS AND METHODS

Sixty-seven consecutive patients with suspected beta-lactam hypersensitivity reactions were studied. Skin prick tests (SPT), intradermal tests (IDT) and specific IgE determination were performed. In non-immediate reactions, epicutaneous testing was also done. If all were negative, a drug challenge was performed.

RESULTS

Sixty-seven patients (54 female symbol), with a mean age + or - SD of 36.6 + or -19.3 years (4-78 years) were studied. The self-reported antibiotics were amoxicillin and amoxicillin/clavulanic acid in 30 (45%), penicillin in 24 (36%), cephalosporins in 11 (16%) and flucloxacillin in 2 (3%). SPT and IDT were positive in 6 patients (9%) and specific IgE in 11 (16%). Only one patient had both positive specific IgE and skin tests. Of the remaining 51 cases, 33 underwent a drug challenge with the culprit antibiotic, with a positive reaction in 2 (6%). In all positive cases and when a drug challenge with the suspected antibiotic was not indicated, a challenge with an alternative drug was done, all with negative results.

CONCLUSIONS

Of the 67 studied cases with history of beta-lactam hypersensitivity reactions, 18 (27%) were confirmed after testing. A combination of skin testing, specific IgE determination and drug challenge is necessary since none has sufficient sensitivity to be used alone.

Age-related reduction in microcolumnar structure correlates with cognitive decline in ventral but not dorsal area 46 of the rhesus monkey

The age-related decline in cognitive function that is observed in normal aging monkeys and humans occurs without significant loss of cortical neurons. This suggests that cognitive impairment results from subtle, sub-lethal changes in the cortex. Recently, changes in the structural coherence in mini- or microcolumns without loss of neurons have been linked to loss of function. Here we use a density map method to quantify microcolumnar structure in both banks of the sulcus principalis (prefrontal cortical area 46) of 16 (ventral) and 19 (dorsal) behaviorally tested female rhesus monkeys from 6 to 33 years of age. While total neuronal density does not change with age in either of these banks, there is a significant age-related reduction in the strength of microcolumns in both regions on the order of 40%. This likely reflects a subtle but definite loss of organization in the structure of the cortical microcolumn. The reduction in strength in ventral area 46 correlates with cognitive impairments in learning and memory while the reduction in dorsal area 46 does not. This result is congruent with published data attributing cognitive functions to ventral area 46 that are similar to our particular cognitive battery which does not optimally tap cognitive functions attributed to dorsal area 46. While the exact mechanisms underlying this loss of microcolumnar organization remain to be determined, it is plausible that they reflect age-related alterations in dendritic and/or axonal organization which alter connectivity and may contribute to age-related declines in cognitive performance.

Automated identification of neurons and their locations

Individual locations of many neuronal cell bodies (>10(4)) are needed to enable statistically significant measurements of spatial organization within the brain such as nearest-neighbour and microcolumnarity measurements. In this paper, we introduce an Automated Neuron Recognition Algorithm (ANRA) which obtains the (x, y) location of individual neurons within digitized images of Nissl-stained, 30 microm thick, frozen sections of the cerebral cortex of the Rhesus monkey. Identification of neurons within such Nissl-stained sections is inherently difficult due to the variability in neuron staining, the overlap of neurons, the presence of partial or damaged neurons at tissue surfaces, and the presence of non-neuron objects, such as glial cells, blood vessels, and random artefacts. To overcome these challenges and identify neurons, ANRA applies a combination of image segmentation and machine learning. The steps involve active contour segmentation to find outlines of potential neuron cell bodies followed by artificial neural network training using the segmentation properties (size, optical density, gyration, etc.) to distinguish between neuron and non-neuron segmentations. ANRA positively identifies 86 +/- 5% neurons with 15 +/- 8% error (mean +/- SD) on a wide range of Nissl-stained images, whereas semi-automatic methods obtain 80 +/- 7%/17 +/- 12%. A further advantage of ANRA is that it affords an unlimited increase in speed from semi-automatic methods, and is computationally efficient, with the ability to recognize approximately 100 neurons per minute using a standard personal computer. ANRA is amenable to analysis of huge photo-montages of Nissl-stained tissue, thereby opening the door to fast, efficient and quantitative analysis of vast stores of archival material that exist in laboratories and research collections around the world.

Role of electrostatic interactions in amyloid beta-protein (A beta) oligomer formation: a discrete molecular dynamics study

Pathological folding and oligomer formation of the amyloid beta-protein (A beta) are widely perceived as central to Alzheimer's disease. Experimental approaches to study A beta self-assembly provide limited information because most relevant aggregates are quasi-stable and inhomogeneous. We apply a discrete molecular dynamics approach combined with a four-bead protein model to study oligomer formation of A beta. We address the differences between the two most common A beta alloforms, A beta 40 and A beta 42, which oligomerize differently in vitro. Our previous study showed that, despite simplifications, our discrete molecular dynamics approach accounts for the experimentally observed differences between A beta 40 and A beta 42 and yields structural predictions amenable to in vitro testing. Here we study how the presence of electrostatic interactions (EIs) between pairs of charged amino acids affects A beta 40 and A beta 42 oligomer formation. Our results indicate that EIs promote formation of larger oligomers in both A beta 40 and A beta 42. Both A beta 40 and A beta 42 display a peak at trimers/tetramers, but A beta 42 displays additional peaks at nonamers and tetradecamers. EIs thus shift the oligomer size distributions to larger oligomers. Nonetheless, the A beta 40 size distribution remains unimodal, whereas the A beta 42 distribution is trimodal, as observed experimentally. We show that structural differences between A beta 40 and A beta 42 that already appear in the monomer folding, are not affected by EIs. A beta 42 folded structure is characterized by a turn in the C-terminus that is not present in A beta 40. We show that the same C-terminal region is also responsible for the strongest intermolecular contacts in A beta 42 pentamers and larger oligomers. Our results suggest that this C-terminal region plays a key role in the formation of A beta 42 oligomers and the relative importance of this region increases in the presence of EIs. These results suggest that inhibitors targeting the C-terminal region of A beta 42 oligomers may be able to prevent oligomer formation or structurally modify the assemblies to reduce their toxicity.

Molecular dynamics simulation of amyloid beta dimer formation

Recent experiments with amyloid beta (Abeta) peptide indicate that formation of toxic oligomers may be an important contribution to the onset of Alzheimer's disease. The toxicity of Abeta oligomers depends on their structure, which is governed by assembly dynamics. Due to limitations of current experimental techniques, a detailed knowledge of oligomer structure at the atomic level is missing. We introduce a molecular dynamics approach to study Abeta dimer formation. 1), We use discrete molecular dynamics simulations of a coarse-grained model to identify a variety of dimer conformations; and 2), we employ all-atom molecular mechanics simulations to estimate thermodynamic stability of all dimer conformations. Our simulations of a coarse-grained Abeta peptide model predicts 10 different planar beta-strand dimer conformations. We then estimate the free energies of all dimer conformations in all-atom molecular mechanics simulations with explicit water. We compare the free energies of Abeta(1-42) and Abeta(1-40) dimers. We find that 1), dimer conformations have higher free energies compared to their corresponding monomeric states; and 2), the free-energy difference between the Abeta(1-42) and the corresponding Abeta(1-40) dimer conformation is not significant. Our results suggest that Abeta oligomerization is not accompanied by the formation of thermodynamically stable planar beta-strand dimers.

In silico study of amyloid beta-protein folding and oligomerization

Experimental findings suggest that oligomeric forms of the amyloid beta protein (Abeta) play a critical role in Alzheimer's disease. Thus, elucidating their structure and the mechanisms of their formation is critical for developing therapeutic agents. We use discrete molecular dynamics simulations and a four-bead protein model to study oligomerization of two predominant alloforms, Abeta40 and Abeta42, at the atomic level. The four-bead model incorporates backbone hydrogen-bond interactions and amino acid-specific interactions mediated through hydrophobic and hydrophilic elements of the side chains. During the simulations we observe monomer folding and aggregation of monomers into oligomers of variable sizes. Abeta40 forms significantly more dimers than Abeta42, whereas pentamers are significantly more abundant in Abeta42 relative to Abeta40. Structure analysis reveals a turn centered at Gly-37-Gly-38 that is present in a folded Abeta42 monomer but not in a folded Abeta40 monomer and is associated with the first contacts that form during monomer folding. Our results suggest that this turn plays an important role in Abeta42 pentamer formation. Abeta pentamers have a globular structure comprising hydrophobic residues within the pentamer's core and hydrophilic N-terminal residues at the surface of the pentamer. The N termini of Abeta40 pentamers are more spatially restricted than Abeta42 pentamers. Abeta40 pentamers form a beta-strand structure involving Ala-2-Phe-4, which is absent in Abeta42 pentamers. These structural differences imply a different degree of hydrophobic core exposure between pentamers of the two alloforms, with the hydrophobic core of the Abeta42 pentamer being more exposed and thus more prone to form larger oligomers.

Health-Related Quality of Life in HIV Patients Switching to Twice-Daily Indinavir/Ritonavir Regimen or Continuing with Three-Times-Daily Indinavir-Based Therapy

Objective

To evaluate health-related quality of life (HRQoL) changes in patients treated with indinavir three-times daily after switching to a twice-daily indinavir/ritonavir regimen or continuing with the same regimen.

Methods

Patients on HAART including indinavir three-times-daily with undetectable viral load were randomly assigned to continue with this therapy or to change to a twice-daily indinavir/ritonavir (800/100 mg) regimen. The Medical Outcomes Study HIV Health Survey (MOS-HIV) questionnaire was used as the HRQoL measure.

Results

A total of 118 patients participated in the study, of which 59 (50%) were randomly assigned to continue with the three-times-daily regimen. Patients had a mean age of 39 years and 80% of them were male. At baseline, subjects included in the three-times-daily group presented a significantly greater number of symptoms than subjects in the twice-daily group, but no statistically significant differences were observed in MOS-HIV scores between the groups. In the intention-to-treat (ITT) analysis, a reduction in HRQoL scores was observed in both groups, which was greater in the twice-daily group. In the per protocol analysis, reduction of HRQoL was minimal.

Conclusions

A HRQoL deterioration, greater in the twice-daily group, was observed in this study in the ITT analysis, while HRQoL remained stable in both groups in patients who continued with and tolerated the allocated regimen.

Discrete molecular dynamics simulations of peptide aggregation

We study the aggregation of peptides using the discrete molecular dynamics simulations. Specifically, at temperatures above the alpha-helix melting temperature of a single peptide, the model peptides aggregate into a multilayer parallel beta-sheet structure. This structure has an interstrand distance of 4.8 A and an intersheet distance of 10 A, which agree with experimental observations. Our model explains these results as follows: hydrogen-bond interactions give rise to the interstrand spacing in beta sheets, while Gō interactions between side chains make beta strands parallel to each other and allow beta sheets to pack into layers. An important feature of our results is that the aggregates contain free edges, which may allow for further aggregation of model peptides to form elongated fibrils.

Neuron recognition by parallel Potts segmentation

Identifying neurons and their spatial coordinates in images of the cerebral cortex is a necessary step in the quantitative analysis of spatial organization in the brain. This is especially important in the study of Alzheimer's disease (AD), in which spatial neuronal organization and relationships are highly disrupted because of neuronal loss. To automate neuron recognition by using high-resolution confocal microscope images from human brain tissue, we propose a recognition method based on statistical physics that consists of image preprocessing, parallel image segmentation, and cluster selection on the basis of shape, optical density, and size. We segment a preprocessed digital image into clusters by applying Monte Carlo simulations of a q-state inhomogeneous Potts model. We then select the range of Potts segmentation parameters to yield an ideal recognition of simplified objects in the test image. We apply our parallel segmentation method to control individuals and to AD patients and achieve recognition of 98% (for a control) and 93% (for an AD patient), with at most 3% false clusters.

Neurotoxic effects of thioflavin S-positive amyloid deposits in transgenic mice and Alzheimer's disease

Despite extensive deposition of putatively neurotoxic amyloid-beta (Abeta) protein in the brain, it has not been possible to demonstrate an association of Abeta deposits with neuronal loss in Alzheimer's disease (AD), and neuronal loss is minimal in transgenic mouse models of AD. Using triple immunostaining confocal microscopy and analyzing the images with the cross-correlation density map method from statistical physics, we directly compared Abeta deposition, Abeta morphology, and neuronal architecture. We found dramatic, focal neuronal toxicity associated primarily with thioflavin S-positive fibrillar Abeta deposits in both AD and PSAPP mice. These results, along with computer simulations, suggest that Abeta develops neurotoxic properties in vivo when it adopts a fibrillar beta-pleated sheet conformation.

Plaque-induced abnormalities in neurite geometry in transgenic models of Alzheimer disease: implications for neural system disruption

Neurites that pass through amyloid-beta deposits in Alzheimer disease (AD) undergo 3 changes: they develop phosphorylated tau immunoreactivity; the density of SMI-32-positive dendrites diminishes; and they also develop a marked alteration in their geometric features, changing from being nearly straight to being quite curvy. The extent to which the latter 2 phenomena are related to phosphorylated tau is unknown. We have now examined whether amyloid-beta deposits in APP695Sw transgenic mice, which have only rare phosphorylated tau containing neurites. develop these changes. We found that dendritic density is diminished within the boundaries of amyloid-beta plaques, with the greatest loss (about 80%, p < 0.001) within the boundaries of thioflavine S cores. Remaining dendrites within plaques develop substantial morphological alterations quantitatively similar to those seen in AD. A statistically significant but smaller degree of change in geometry was seen in the immediate vicinity around plaques, suggesting a propagation of cytoskeletal disruption from the center of the plaque outward. We examined the possible physiological consequences of this change in dendritic geometry using a standard cable-theory model. We found a predicted delay of several milliseconds in about one quarter of the dendrites passing through a thioflavine S plaque. These results are consistent with previous observations in AD, and suggest that thioflavine S-positive amyloid-beta deposits have a marked effect on dendritic microarchitecture in the cortex, even in the relative absence of phosphorylated tau alterations.

Description of microcolumnar ensembles in association cortex and their disruption in Alzheimer and Lewy body dementias

The cortex of the brain is organized into clear horizontal layers, laminae, which subserve much of the connectional anatomy of the brain. We hypothesize that there is also a vertical anatomical organization that might subserve local interactions of neuronal functional units, in accord with longstanding electrophysiological observations. We develop and apply a general quantitative method, inspired by analogous methods in condensed matter physics, to examine the anatomical organization of the cortex in human brain. We find, in addition to obvious laminae, anatomical evidence for tightly packed microcolumnar ensembles containing approximately 11 neurons, with a periodicity of about 80 microm. We examine the structural integrity of this new architectural feature in two common dementing illnesses, Alzheimer disease and dementia with Lewy bodies. In Alzheimer disease, there is a dramatic, nearly complete loss of microcolumnar ensemble organization. The relative degree of loss of microcolumnar ensembles is directly proportional to the number of neurofibrillary tangles, but not related to the amount of amyloid-beta deposition. In dementia with Lewy bodies, a similar disruption of microcolumnar ensemble architecture occurs despite minimal neuronal loss. These observations show that quantitative analysis of complex cortical architecture can be applied to analyze the anatomical basis of brain disorders.

Dynamic feedback in an aggregation-disaggregation model

We study an aggregation-disaggregation model which is relevant to biological processes such as the growth of senile plaques in Alzheimer disease. In this model, during the aggregation each deposited particle has a probability of producing a new particle in its vicinity, while during disaggregation the particles are anihilated randomly. The model is held in a dynamic equilibrium by a feedback mechanism which changes the disaggregation probability in proportion to the change in the total number of particles. We also include surface diffusion which influences the morphology of growing aggregates and colonies. A colony includes the descendents of a single particle. We investigate the statistical properties of the model in two dimensions. We find that unlike the colonies, individual aggregates are fractals with a fractal dimension of D(f)=1.92+/-0.06 in the absence of surface diffusion. We show that the surface diffusion changes the fractal dimension of aggregates: at a small aggregation-disaggregation rate, D(f) is independent of the strength of the surface diffusion, D(f)=1.73+/-0.03. At larger aggregation-disaggregation rates and different strengths of surface diffusion, aggregates with fractal dimensions between D(f)=1.73 and 1.92 form. The steady-state distribution of aggregate sizes is shown to be power law if the aggregation-disaggregation process dominates over the surface diffusion. In the limit of weak aggregation-disaggregation and strong surface diffusion the size distribution is log-normal.

A bacterial single-chain Fv antibody fragment that inhibits binding of its parental anti-E-selectin monoclonal antibody to activated human endothelial cells

Using the polymerase chain reaction, we cloned, modified, and linked antibody variable (V) region coding genes from a mouse hybridoma, and produced a bacterial single-chain Fv (scFv) antibody fragment specific for E-Selectin. A vector of pBR322 origin, bearing the tryptophan promoter and the ompA bacterial signal peptide, was used to direct scFv expression to periplasm. The vector included a six-histidine coding sequence 5' to the scFv for the purification of the expressed protein using immobilized metal affinity chromatography (IMAC). We found that the VH-Linker-VL 32-33 kDa scFv remained insoluble after cellular fractionation, and transmission electron microscopy showed the new protein to be present in the periplasm as inclusion bodies. The scFv was solubilized using urea, purified using IMAC, and renatured to its active form. In a competitive enzyme-linked immunosorbent assay with activated human vein endothelial cells in the solid phase, the scFv competed for binding with the original monoclonal antibody.

Ingestion of chilli pepper (Capsicum annuum) reduces salicylate bioavailability after oral asprin administration in the rat

The bioavailabilities of aspirin (acetylsalicylic acid) and of salicylic acid were studied in male Wistar rats after acute and chronic administration of a Capsicum annuum extract, containing 100 mg of capsaicin per gram. With a single administration of 100 mg/kg of the extract, aspirin blood levels remained unchanged, but salicylic acid bioavailability was reduced in 44% compared with control animals. With a single administration of 300 mg/kg of the extract, aspirin blood levels were undetectable while salicylic acid bioavailability was reduced in 59%. Chronic administration once daily for 4 weeks of 100 and 300 mg/kg of the extract resulted in undetectable aspirin blood levels, while salicylic acid bioavailability was reduced in 63 and 76%, respectively, compared with controls. Results show that Capsicum ingestion reduces oral drug bioavailability, likely as a result of the gastrointestinal effects of capsaicin.

Plaque-induced neurite abnormalities: implications for disruption of neural networks in Alzheimer's disease

The brains of Alzheimer's disease patients contain extracellular Abeta amyloid deposits (senile plaques). Although genetic evidence causally links Abeta deposition to the disease, the mechanism by which Abeta disrupts cortical function is unknown. Using triple immunofluorescent confocal microscopy and three-dimensional reconstructions, we found that neuronal processes that cross through an Abeta deposit are likely to have a radically changed morphology. We modeled the electrophysiological effect of this changed morphology and found a predicted delay of several milliseconds over an average plaque. We propose that this type of delay, played out among thousands of plaques throughout neocortical areas, disrupts the precise temporal firing patterns of action potentials, contributing directly to neural system failure and dementia.

Dynamics of plaque formation in Alzheimer's disease

Plaques that form in the brains of Alzheimer patients are made of deposits of the amyloid-beta peptide. We analyze the time evolution of amyloid-beta deposition in immunostained brain slices from transgenic mice. We find that amyloid-beta deposits appear in clusters whose characteristic size increases from 14 microm in 8-month-old mice to 22 microm in 12-month-old mice. We show that the clustering has implications for the biological growth of amyloid-beta by presenting a growth model that accounts for the experimentally observed structure of individual deposits and predicts the formation of clusters of deposits and their time evolution.

Role of P-selectin expression in hepatic ischemia and reperfusion injury

BACKGROUND

Researchers have shown that reperfusion of ischemic tissues initiates a complex series of reactions that paradoxically injure tissues. Although several mechanisms have been proposed to explain the pathobiology of ischemic/reperfusion (I/R) injury, much attention has focused on adhesion molecules. Our research is intended to show the kinetics of P-selectin in the liver in response to I/R injury.

METHODS

Left-lobar hepatic ischemia was induced for 30 min in 35 C57BL-6 mice and 20 P-selectin-deficient (K-O) mice. P-selectin expression was measured in these mice at 20 min, 2, 5, 12 and 24 h reperfusion times, as well as in control and sham animals. The animals were injected with radio-labeled P-selectin monoclonal antibody and the organs were harvested for counts/g tissue, expressed as the percentage injected dose. Serum liver enzymes were measured and pathological sections of ischemic and control livers were performed. The unpaired t-test was used for statistical analysis.

RESULTS

P-selectin expression showed two peaks in this animal model. The first peak was at 20 min and the second peak at 5 h of reperfusion (p < 0.001). We documented an 8-fold increase in aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels 10 h following I/R injury. Pathological specimens showed periportal necrosis consistent with an ischemic event. P-selectin K-O mice showed no up-regulation as a separate control group, and the liver enzymes were significantly lower than the wild-type mice at 10 h (p < 0.001).

CONCLUSION

P-selectin has a bimodal expression following hepatic I/R injury. The first peak is attributed to the Weibel-Palade bodies and the second to new translational P-selectin. We noted no difference in the up-regulation of P-selectin in the ischemic and non-ischemic liver lobes in the same animal.