Central and mixed apneas in children with obstructive sleep apnea: effect of adenotonsillectomy

PURPOSE

Investigate the effect of adenotonsillectomy on mixed apnea index (MAI) and central apnea index (CAI) in children with moderate-to-severe obstructive sleep apnea syndrome (OSAS).

METHODS

Observational retrospective analysis of polysomnographic data in children diagnosed with moderate-to-severe OSAS and without comorbidity, submitted to adenotonsillectomy.

RESULTS

Data were available for 80 children, 55 boys and 25 girls, with a median age of 3.6 years (2.1-5.9). Before surgery AHI was 14.1 (11.0-18.4) per hour, with a median preoperative OAI of 7.1 (4.1-10.6), MAI of 1.2 (0.6-1.6) and CAI of 1.0 (0.4-2.0). Adenotonsillectomy caused significant improvements in MAI, from 1.2 (0.6-1.6) to 0.5 (0.1-0.8) (p < 0.001) and CAI from 1.0 (0.4-2.0) to 0.5 (0.1-0.9) (p < 0.001). This represents a normalization of MAI in 91.7% and CAI in 75.6% of children that had an abnormal value prior surgery.

CONCLUSION

Non obstructive apneas are common in children with OSAS. Adenotonsillectomy caused significant decrease not only in OAI, but also in MAI and CAI in children with moderate-to-severe OSAS.

Unilateral vocal fold paralysis as a port complication

Unilateral vocal fold paralysis (UVFP) is a frequent finding in otorhinolaryngology practice, but its occurrence as a port complication was very rarely described in English Literature. The authors report a 55-year-old woman with a pancreatic adenocarcinoma who presented a left vocal fold paralysis that occurred concurrently with a venous thrombosis of the left subclavian vein, where a totally implantable venous-access had been previously placed. Although the patient's oncologic disease, that could mislead to a neoplastic cause of the UVFP, the authors came across with an unusual etiology and to their best knowledge, it is the first case of irreversible UVFP associated with onsite thrombosis of the vessel where a port was implanted. The objective of this article is to present and discuss this rare case of UVFP secondary to a port complication and to review the main mechanisms of iatrogenic vocal fold paralysis related to these devices.

Swallowing evaluation in patients who underwent Partial CO2 LASER Epiglottectomy for Sleep Apnea treatment

OBJECTIVE

To evaluate swallowing in patients who underwent CO2 LASER Partial Epiglottectomy (CO2-LPE) for Obstructive Sleep Apnea Syndrome and to assess the risk of aspiration with this technique.

MATERIAL & METHODS

Chart review of adult patients who underwent CO2-LPE between 2016 and 2020, in a secondary care hospital. Patients underwent surgery for OSAS, in accordance to Drug Induced Sleep Endoscopy findings and an objective swallowing evaluation was done at least 6 months after surgery. Eating Assessment Tool (EAT-10) questionnaire was applied and Volume-Viscosity Swallow Test (V-VST) and Fiberoptic Endoscopic Evaluation of Swallowing (FEES) were performed. Dysphagia was classified according to Dysphagia Outcome Severity Scale (DOSS).

RESULTS

Eight patients were included in the study. The mean time between surgery and the swallowing evaluation was 50 (±13,2) months. Only 3 patients presented ≥ 3 points on EAT-10 questionnaire. Two patients presented signs of decreased efficacy of swallowing (piecemeal deglutition) but none had a decrease in safety, according to V-VST. Although 50% of the patients presented some pharyngeal residue on FEES, it was classified as trace to mild in most of the cases. No evidence of penetration or aspiration was identified (DOSS ≥ 6 in all patients).

CONCLUSION

The CO2-LPE is a potential treatment for OSAS patients with epiglottic collapse and no evidence of swallowing safety compromise was found.

Surgical treatment for obstructive sleep apnea: effect on sleep architecture

PURPOSE

Investigate the effect of surgical treatment of obstructive sleep apnea syndrome (OSA) on sleep architecture.

METHODS

Observational retrospective analysis of polysomnographic data of adults diagnosed with OSA, submitted to surgical treatment. Median (25-75th percentile) was used to present the data.

RESULTS

Data were available for 76 adults, 55 men and 21 women, with median age of 49.0 years (41.0-62.0), body mass index of 27.3 kg/m2 (25.3-29.3) and AHI of 17.4 per hour (11.3-22.9) before surgeries. Preoperatively, 93.4% of patients had an abnormal distribution of at least one of the sleep phases. After surgical treatment, we found a significant increase in median N3 sleep percent from 16.9% (8.3-22-7) to 18.9% (15.5-25.4) (p = 0.003). Postoperatively, 18.6% patients that had an abnormal preoperative N1 sleep phase distribution had a normalization of this sleep phase, as also occurred to N2, N3 and REM sleep phases in 44.0%, 23.3% and 63.6% of patients, respectively.

CONCLUSION

This study aims to show the impact of OSA treatment, not only on respiratory events but also on other polysomnographic data often underestimated. Upper airway surgeries have shown to be effective in sleep architecture improvements. There is a trend for sleep distribution normalization, with increase of time spend in profound sleep.

Extract2Chip-Bypassing Protein Purification in Drug Discovery Using Surface Plasmon Resonance

Modern drug discovery relies on combinatorial screening campaigns to find drug molecules targeting specific disease-associated proteins. The success of such campaigns often relies on functional and structural information of the selected therapeutic target, only achievable once its purification is mastered. With the aim of bypassing the protein purification process to gain insights on the druggability, ligand binding, and/or characterization of protein-protein interactions, herein, we describe the Extract2Chip method. This approach builds on the immobilization of site-specific biotinylated proteins of interest, directly from cellular extracts, on avidin-coated sensor chips to allow for the characterization of molecular interactions via surface plasmon resonance (SPR). The developed method was initially validated using Cyclophilin D (CypD) and subsequently applied to other drug discovery projects in which the targets of interest were difficult to express, purify, and crystallize. Extract2Chip was successfully applied to the characterization of Yes-associated protein (YAP): Transcriptional enhancer factor TEF (TEAD1) protein-protein interaction inhibitors, in the validation of a ternary complex assembly composed of Dyskerin pseudouridine synthase 1 (DKC1) and RuvBL1/RuvBL2, and in the establishment of a fast-screening platform to select the most suitable NUAK family SNF1-like kinase 2 (NUAK2) surrogate for binding and structural studies. The described method paves the way for a potential revival of the many drug discovery campaigns that have failed to deliver due to the lack of suitable and sufficient protein supply.

Severe Pediatric Sleep Apnea: Drug-Induced Sleep Endoscopy Based Surgery

Although adenotonsillectomy is the recommended treatment of obstructive sleep apnea (OSA) in children, some patients with preoperative severe OSA (Apnea-hypopnea index/AHI > 10) remain symptomatic after surgery and may need further workup. This study aims to: (1) analyse preoperative factors and its relation with surgical failure/persistent OSA (AHI > 5 after adenotonsillectomy) in severe pediatric OSA; (2) determine the levels of airway collapse during DISE (drug induced sleep endoscopy) in cases of surgical failure; (3) evaluate the efficacy of targeted surgery based on DISE findings. This retrospective study was conducted between August and September 2020. Across 9 years (from 2011 to 2020), all children diagnosed with severe OSA in our Hospital underwent adenotonsillectomy and repeated type 1 polysomnography (PSG) 3 months after surgery. Cases of surgical failure underwent DISE for planning eventual directed surgery. Chi-square test was used to assess the relationship between persistent OSA and preoperative patients' characteristics. 80 cases of severe pediatric OSA were diagnosed (68.8% males; mean age: 4.3 years-standard deviation: 2.49; mean AHI: 16.3-standard deviation 7.14) in the aforementioned period. We found a significant association between surgical failure (11.3% of cases; mean AHI: 6.9-SD 0.91) and obesity (p = 0.002; confidence level of 95%). Neither preoperative AHI nor other PSG parameters were associated with surgical failure. In cases of surgical failure, epiglottis collapse was present in every DISEs and adenoid tissue was present in 66% of children. All cases of surgical failure had directed surgery and surgical cure (AHI ≤ 5) was obtained in 100% of cases. This study suggests that obesity is the strongest predictor of surgical failure in children with severe OSA who undergo adenotonsillectomy. Epiglottis collapse and presence of adenoid tissue are the most common findings in postoperative DISEs of children with persistent OSA after primary surgery. DISE based surgery seems a safe and effective tool to manage persistent OSA after adenotonsillectomy.

Treatment of otomycosis with clotrimazole: results accordingly with the fungus isolated

BACKGROUND

Otomycosis is usually caused by Candida spp or Aspergillus spp. While Candida is usually multissensitive to available antifungals, Aspergillus is not. Topical antifungals for otomycosis that are available in Portugal are scarce, and systemic treatments have too many interactions and contraindications.

OBJECTIVES

Determine otomycosis epidemiology, microbiology and treatment results.

METHODS

Observational study that included patients followed in Professor Doutor Fernando Fonseca Hospital, between 2011 and 2020. Otomycosis diagnosis was obtained through ear drainage culture, and every case was treated with 1% clotrimazole ear drops plus ear cleaning once per week.

RESULTS

Aspergillus was found in ear drainage culture in 43.9% of patients and Candida in the remaining. There was a significant statistical difference between patients with otomycosis caused by Aspergillus versus Candida in treatment duration from 25.0 days (16.5-43.0) versus 14.0 days (7.0-18.5) (p < .001), respectively.

CONCLUSIONS

Otomycosis was more frequently caused by Candida, and this type of otomycosis is treated faster with clotrimazole 10 mg/dL plus ear cleaning, when compared with otomycosis by Aspergillus.

SIGNIFICANCE

If otomycosis causative agent is identified or suspected, a prediction of the time needed till the resolution of otomycosis can be made, when clotrimazole ear drops are used.

Optimization of TEAD P-Site Binding Fragment Hit into In Vivo Active Lead

The dysregulated Hippo pathway and, consequently, hyperactivity of the transcriptional YAP/TAZ-TEAD complexes is associated with diseases such as cancer. Prevention of YAP/TAZ-TEAD triggered gene transcription is an attractive strategy for therapeutic intervention. The deeply buried and conserved lipidation pocket (P-site) of the TEAD transcription factors is druggable. The discovery and optimization of a P-site binding fragment (1) are described. Utilizing structure-based design, enhancement in target potency was engineered into the hit, capitalizing on the established X-ray structure of TEAD1. The efforts culminated in the optimized in vivo tool MSC-4106, which exhibited desirable potency, mouse pharmacokinetic properties, and in vivo efficacy. In close correlation to compound exposure, the time- and dose-dependent downregulation of a proximal biomarker could be shown.

Genome-wide association studies for sperm traits in Assaf sheep breed

Sperm quality traits routinely collected by artificial insemination (AI) center for rams progeny test are related with the capacity to produce sperm doses for AI and, in more or less grade, with males' fertility. Low-quality ejaculates are unuseful to perform AI sperm doses, which suppose high economic loses for the AI center. Moreover, sperm quality traits have low heritability values which make traditional genetic selection little efficient to its improvement. In this work, a genome-wide association study (GWAS) was conducted by using sperm quality traits data and 50 K Affymetrix custom chip genotypes of 429 rams of Assaf breed from OVIGEN AI centre. Furthermore, 47 of these rams were also genotyped with the Illumina HD Ovine BeadChip, and therefore HD genotypes were imputed for all rams with phenotype data. Previous to the GWAS, a linear regression model was fitted including sperm traits as dependent variables; the flock of origin, date of sperm collection, and jump number as fixed effects; rams age at collection in months as covariate; and ram permanent effect as random. Pseudo-phenotypes obtained from this model were used as input for GWAS. Associations at the chromosome-wise level (FDR 10%) of 76 single-nucleotide polymorphisms (SNPs) in 4 chromosomes for ejaculate concentration (CON), 20 SNPs in 3 chromosomes for ejaculate volume (VOL), 32 SNPs in 1 chromosome for ejaculate number of spermatozoa (SPZ), and 23 SNPs for spermatozoa mass motility (MOT) in 17 chromosomes were found. Only SNPs associated with MOT overcame the genome-wide significance level. Some candidate genes for sperm traits variability were SLC9C1 (OAR1), TSN (OAR2), and FUT10 (OAR26) for MOT;. DOCK2, CPLANE1, SPEF2, and RAI14 (OAR16) for CON; SCAPER and PSMA4 (OAR18) for VOL; and PARM1 and LOC101110593 (OAR6) for SPZ. SNPs associated with sperm traits were not found to be correlated with milk production genetic variation; however, the high frequencies of some SNPs with negative effect over sperm traits found in animals at the top milk yield estimated breeding values (EBVs) ranking would allow to exert some selective presure to improve rams sperm performances. Effects and frequencies of some of the SNPs detected over sperm quality traits make these variants good candidates to be used in marker-assisted selection to improve sperm characteristics of Assaf rams and AI center efficiency to produce sperm doses.

Predictors of OSA following adenotonsillectomy in children with trisomy 21

OBJECTIVES

Given that 30%-50% of children with trisomy 21 have persistent obstructive sleep apnoea (OSA) after adenotonsillectomy, we evaluated whether demographic, clinical and polysomnographic factors predicted persistent OSA and OSA severity after adenotonsillectomy.

DESIGN

Retrospective study.

SETTING

Secondary care hospital.

PARTICIPANTS

Retrospective review of 32 children with the diagnosis of trisomy 21 and OSA by polysomnography who underwent adenotonsillectomy, from January 2010 to December 2018.

MAIN OUTCOME AND MEASURE

Non-parametric analysis was used to compare pre- and postoperative factors, and regression was used to model persistent OSA and OSA severity.

RESULTS

Thirty-two children were included (17 males, median age 10.00 ± 8.00 years, median body mass index z-score 0.89 ± 1.25). Overall, adenotonsillectomy resulted in a significant improvement in median obstructive apnoea-hypopnoea index (oAHI) from 7.5 ± 8.95 to 4.40 ± 4.38 events per hour (P < .001) and in median OSA-18 score from 85.00 ± 12.00 to 61.00 ± 37.75 (P < .001). Persistent OSA was found in 56.25% of the children. Univariate regression suggests that postoperative OSA-18 score was associated with persistent OSA after adenotonsillectomy. Preoperative oAHI, preoperative oxygen desaturation index, pre- and postoperative OSA-18 scores correlated with OSA severity after adenotonsillectomy. However, in a multivariate model only the postoperative OSA-18 score correlated with OSA severity after adenotonsillectomy.

CONCLUSIONS

Although adenotonsillectomy results in a significant improvement of OSA in children with trisomy 21, more than half of the children had persistent OSA. The postoperative OSA-18 score was associated both with persistent OSA and OSA severity after adenotonsillectomy.

Auditory Brainstem Response in Preterm Infants in the Neonatal Intensive Care Unit

OBJECTIVE

To analyze auditory brainstem response (ABR) findings of preterm and term infants in the neonatal intensive care unit (NICU) with perinatal problems.

STUDY DESIGN

Case series with chart review.

SETTING

Secondary care hospital.

METHODS

Analysis consisted of a consecutive series of 101 infants (69 preterm and 32 term) admitted in the NICU of Hospital Fernando Fonseca between 2016 and 2018 with perinatal problems who underwent an ABR evaluation.

RESULTS

The major perinatal problems identified were hyperbilirubinemia, intravenous gentamicin >5 days, mechanical ventilation >5 days, congenital cytomegalovirus infection, meningitis, and periventricular hemorrhage. Gentamicin use significantly increased the absolute latency of wave I in preterm infants (95% CI, 0.01-0.37; P = .037). Mechanical ventilation significantly decreased the latency of wave V and intervals I-V and III-V in preterm infants (95% CI, -0.35 to -0.22; P = .026; 95% CI, -0.33 to -0.00; P = .001; 95% CI, -0.46 to 0.12; P = .049). Congenital cytomegalovirus significantly decreased interval III-V in preterm infants (95% CI, -0.36 to -0.01; P = .042).Multivariate analysis revealed that gentamicin use, lower gestational age, and lower birth weight predicted an increased ABR threshold in preterm infants (95% CI, 1.64-15.31; P = .016; 95% CI -1.72 to -0.09; P = .030; 95% CI, -14.55 to -0.63; P = .033). ABR measurements in term infants were not significantly altered, with the exception of an increased latency of wave III with a lower gestational age (95% CI, -0.49 to -0.01; P = .038).

CONCLUSIONS

These findings suggest that perinatal problems in the NICU significantly impair the ABR threshold and the auditory pathway maturational process in preterm but not term infants.

Drug-Induced Sleep Endoscopy in Pediatric Obstructive Sleep Apnea

OBJECTIVE

To describe drug-induced sleep endoscopy (DISE) findings in children with obstructive sleep apnea and to differentiate them between surgically naïve children and children who had adenotonsillectomy performed.

STUDY DESIGN

Retrospective case series with chart review.

SETTING

Secondary care hospital.

SUBJECTS AND METHODS

A cohort of 56 children with the diagnosis of obstructive sleep apnea was submitted to DISE and subsequent upper airway surgery: 23 were surgically naïve, and 33 had persistent obstructive sleep apnea after adenotonsillectomy. Comparisons between groups were calculated with chi-square test and Student's t test. Simple linear regression was used to model polysomnographic indices.

RESULTS

In surgically naïve children, the most common sites of obstruction were the adenoids (78.2%) and the lateral pharyngeal walls/tonsils (82.6%). In children with persistent obstructive sleep apnea after adenotonsillectomy, the most common sites of obstruction were the adenoids (54.5%), followed by the supraglottis (48.5%) and the tongue base (45.5%). No correlation was found between obstructive apnea-hypopnea index and DISE findings. Simple linear regression revealed that the degree of obstruction at the tongue base (β = -0.73; 95% CI, -1.22 to -0.25; P = .004) and the presence of multilevel obstruction (β = -1.75; 95% CI, -3.20 to -0.30; P = .02) predicted saturation nadir in children with persistent obstructive sleep apnea after adenotonsillectomy.

CONCLUSION

DISE findings differed between surgically naïve children and children with persistent obstructive sleep apnea after adenotonsillectomy. Increased obstruction at the level of the tongue base and the presence of multilevel obstruction predicted a lower saturation nadir in children with persistent obstructive sleep apnea after adenotonsillectomy.

Shedding Light on the Interaction of Human Anti-Apoptotic Bcl-2 Protein with Ligands through Biophysical and in Silico Studies

Bcl-2 protein is involved in cell apoptosis and is considered an interesting target for anti-cancer therapy. The present study aims to understand the stability and conformational changes of Bcl-2 upon interaction with the inhibitor venetoclax, and to explore other drug-target regions. We combined biophysical and in silico approaches to understand the mechanism of ligand binding to Bcl-2. Thermal shift assay (TSA) and urea electrophoresis showed a significant increase in protein stability upon venetoclax incubation, which is corroborated by molecular docking and molecular dynamics simulations. An 18 °C shift in Bcl-2 melting temperature was observed in the TSA, corresponding to a binding affinity multiple times higher than that of any other reported Bcl-2 inhibitor. This protein-ligand interaction does not implicate alternations in protein conformation, as suggested by SAXS. Additionally, bioinformatics approaches were used to identify deleterious non-synonymous single nucleotide polymorphisms (nsSNPs) of Bcl-2 and their impact on venetoclax binding, suggesting that venetoclax interaction is generally favored against these deleterious nsSNPs. Apart from the BH3 binding groove of Bcl-2, the flexible loop domain (FLD) also plays an important role in regulating the apoptotic process. High-throughput virtual screening (HTVS) identified 5 putative FLD inhibitors from the Zinc database, showing nanomolar affinity toward the FLD of Bcl-2.

The Crystal Structure of the R280K Mutant of Human p53 Explains the Loss of DNA Binding

The p53 tumor suppressor is widely found to be mutated in human cancer. This protein is regarded as a molecular hub regulating different cell responses, namely cell death. Compelling data have demonstrated that the impairment of p53 activity correlates with tumor development and maintenance. For these reasons, the reactivation of p53 function is regarded as a promising strategy to halt cancer. In the present work, the recombinant mutant p53R280K DNA binding domain (DBD) was produced for the first time, and its crystal structure was determined in the absence of DNA to a resolution of 2.0 Å. The solved structure contains four molecules in the asymmetric unit, four zinc(II) ions, and 336 water molecules. The structure was compared with the wild-type p53 DBD structure, isolated and in complex with DNA. These comparisons contributed to a deeper understanding of the mutant p53R280K structure, as well as the loss of DNA binding related to halted transcriptional activity. The structural information derived may also contribute to the rational design of mutant p53 reactivating molecules with potential application in cancer treatment.

Prospective multicentre study on barbed reposition pharyngoplasty standing alone or as a part of multilevel surgery for sleep apnoea

OBJECTIVES

The aim of this study was to demonstrate in a prospective multicentre study that Barbed Reposition Pharyngoplasty (BRP) procedure is safe and effective in management of obstructive sleep apnoea/hypopnea syndrome (OSAHS) patients.

DESIGN

Prospective study.

SETTING

Multicentre study.

PARTICIPANTS

Patients suffering from obstructive sleep apnoea.

MAIN OUTCOMES MEASURES

Values of postoperative apnoea-hypopnea index (AHI), oxygen desaturation index (ODI), epworth sleepiness scale (ESS).

RESULTS

111 Barbed Reposition Pharyngoplasty procedures standing alone or as a part of multilevel surgery for OSAHS, performed between January and September 2016, were analysed in 15 different centres. The average hospitalisation period was 2.5 ± 0.5 days. The mean patient age was 46.3 ± 10.5 years. The average body mass index at the time of the procedure was 27.9 ± 3.2, and the majority of the patients were men (83%). The mean preoperative and postoperative apnoea/hypopnea index was 33.4 ± 19.5 and 13.5 ± 10.3, respectively (P < .001). The mean preoperative and postoperative ESS score was 10.2 ± 4.5 and 6.1 ± 3.6, respectively (P < .001). The mean preoperative and postoperative ODI were 29.6 ± 20.7 and 12.7 ± 10.8, respectively (P < .001).

CONCLUSIONS

Patients undergoing BRP standing alone or as part of a multilevel approach for the treatment of OSAHS have a reasonable expectation for success with minimal morbidity.

Chiral nanostructure in polymers under different deposition conditions observed using atomic force microscopy of monolayers: poly(phenylacetylene)s as a case study

Dynamic poly(phenylacetylene)s (PPAs) adopt helical structures with different elongation or helical senses depending on the types of pendants. Hence, a good knowledge of the parameters that define their structures becomes a key factor in the understanding of their properties and functions. Herein, the techniques used for the study of the secondary structure of PPAs using atomic-force microscopy (AFM) are presented, with special attention directed towards the methods used for the preparation of monolayers, and their consequences in the quality of the AFM images. Thus, monolayers formed by drop casting, spin coating followed by crystallization or annealing, Langmuir-Blodgett and Langmuir-Schaefer methods, onto highly oriented pyrolytic graphite (HOPG) or mica, are described, together with the AFM images and the resulting helical structure obtained for different PPAs. Furthermore, some conclusions are drawn both on the adequacy of the different techniques for the formation of monolayers and on the solid supports utilized to elucidate the secondary structure of different PPAs.

Plasmonic control of extraordinary optical transmission in the infrared regime

We demonstrate that the spectral location of extraordinary optical transmission (EOT) resonances in metallic arrays of rectangular holes can be plasmonically tuned in the near and mid-infrared ranges. The experiments have been performed on patterned gold films. We focus on a subset of localized resonances occurring close to the cut-off wavelength of the holes, λ _c. Metals are usually regarded as perfect electric conductors in the infrared regime, with an EOT cut-off resonance found around λ _c = 2 L for rectangular holes (L being the long edge). For real metals, the penetration of the electromagnetic fields is simply seen as effectively enlarging L. However, by changing the hole short edge, we have found that λ _c varies due to the excitation of gap surface plasmon polaritons. Finite-element calculations confirm that in these high aspect ratio rectangles with short edges two important aspects have to be taken into account in order to explain the experiments: the finite conductivity of the metal and the excitation of gap-surface plasmons inside the nanoholes.

Conservation in the mechanism of glucuronoxylan hydrolysis revealed by the structure of glucuronoxylan xylanohydrolase (CtXyn30A) from Clostridium thermocellum

Glucuronoxylan endo-β-1,4-xylanases cleave the xylan chain specifically at sites containing 4-O-methylglucuronic acid substitutions. These enzymes have recently received considerable attention owing to their importance in the cooperative hydrolysis of heteropolysaccharides. However, little is known about the hydrolysis of glucuronoxylans in extreme environments. Here, the structure of a thermostable family 30 glucuronoxylan endo-β-1,4-xylanase (CtXyn30A) from Clostridium thermocellum is reported. CtXyn30A is part of the cellulosome, a highly elaborate multi-enzyme complex secreted by the bacterium to efficiently deconstruct plant cell-wall carbohydrates. CtXyn30A preferably hydrolyses glucuronoxylans and displays maximum activity at pH 6.0 and 70°C. The structure of CtXyn30A displays a (β/α)₈ TIM-barrel core with a side-associated β-sheet domain. Structural analysis of the CtXyn30A mutant E225A, solved in the presence of xylotetraose, revealed xylotetraose-cleavage oligosaccharides partially occupying subsites -3 to +2. The sugar ring at the +1 subsite is held in place by hydrophobic stacking interactions between Tyr139 and Tyr200 and hydrogen bonds to the OH group of Tyr227. Although family 30 glycoside hydrolases are retaining enzymes, the xylopyranosyl ring at the -1 subsite of CtXyn30A-E225A appears in the α-anomeric configuration. A set of residues were found to be strictly conserved in glucuronoxylan endo-β-1,4-xylanases and constitute the molecular determinants of the restricted specificity displayed by these enzymes. CtXyn30A is the first thermostable glucuronoxylan endo-β-1,4-xylanase described to date. This work reveals that substrate recognition by both thermophilic and mesophilic glucuronoxylan endo-β-1,4-xylanases is modulated by a conserved set of residues.

Extensive upper respiratory tract sarcoidosis

Sarcoidosis is a chronic granulomatous disease of unknown aetiology. It can affect any part of the organism, although the lung is the most frequently affected organ. Upper airway involvement is rare, particularly if isolated. Sarcoidosis is a diagnosis of exclusion, established by histological evidence of non-caseating granulomas and the absence of other granulomatous diseases. The authors report a case of a man with sarcoidosis manifesting as a chronic inflammatory stenotic condition of the upper respiratory tract and trachea.

Helical sense selective domains and enantiomeric superhelices generated by Langmuir-Schaefer deposition of an axially racemic chiral helical polymer

The chiral polymer poly-(R)-1 behaves in solution, despite its chiral pendants, as a dynamic axially racemic (i.e., 1 : 1) mixture of left- and right-handed helices, but its deposition on graphite by a Langmuir-Schaefer (LS) technique leads to a helical sense-selective packing that forms separate enantiomeric domains of left- and right-handed helical chains observed by high resolution atomic force microscopy (AFM). The polymer structure within these domains is very uniform, seldom altered by the presence of reversals, grouped always in contiguous pairs maintaining a single helical sense along the polymer chain. The LS deposition technique has been shown to be crucial to obtain good quality monolayers from poly-(R)-1 and other poly(phenylacetylene)s (PPAs: poly-2, poly-3 and poly-4) with short pendants, where spin coating, drop casting and Langmuir-Blodgett (LB) failed, and suggests that this technique could be the method of choice for the preparation of 2D monolayers for high resolution AFM studies of PPAs with short pendants. Key helical parameters (i.e., sense, pitch, packing angle) are easily measured in this way.

Phragmites sp. physiological changes in a constructed wetland treating an effluent contaminated with a diazo dye (DR81)

The role of Phragmites sp. in phytoremediation of wastewaters containing azo dyes is still, in many ways, at its initial stage of investigation. This plant response to the long-term exposure to a highly conjugated di-azo dye (Direct Red 81, DR81) was assessed using a vertical flow constructed wetland, at pilot scale. A reed bed fed with water was used as control. Changes in photosynthetic pigment content in response to the plant contact with synthetic DR81 effluent highlight Phragmites plasticity. Phragmites leaf enzymatic system responded rapidly to the stress imposed; in general, within 1 day, the up-regulation of foliar reactive oxygen species-scavenging enzymes (especially superoxide dismutase, ascorbate peroxidase (APX), glutathione peroxidase (GPX) and peroxidase) was noticed as plants entered in contact with synthetic DR81 effluent. This prompt activation decreased the endogenous levels of H₂O₂ and the malonyldialdehyde content beyond reference values. Glutathione S-transferase (GST) activity intensification was not enough to cope with stress imposed by DR81. GPX activity was pivotal for the detoxification pathways after a 24-h exposure. Carotenoid pool was depleted during this shock. After the imposed DR81 stress, plants were harvested. In the next vegetative cycle, Phragmites had already recovered from the chemical stress. Principal component analysis (PCA) highlights the role of GPX, GST, APX, and carotenoids along catalase (CAT) in the detoxification process.

Overexpression, crystallization and preliminary X-ray crystallographic analysis of glucuronoxylan xylanohydrolase (Xyn30A) from Clostridium thermocellum

The modular carbohydrate-active enzyme belonging to glycoside hydrolase family 30 (GH30) from Clostridium thermocellum (CtXynGH30) is a cellulosomal protein which plays an important role in plant cell-wall degradation. The full-length CtXynGH30 contains an N-terminal catalytic module (Xyn30A) followed by a family 6 carbohydrate-binding module (CBM6) and a dockerin at the C-terminus. The recombinant protein has a molecular mass of 45 kDa. Preliminary structural characterization was carried out on Xyn30A crystallized in different conditions. All tested crystals belonged to space group P1 with one molecule in the asymmetric unit. Molecular replacement has been used to solve the Xyn30A structure.

Thoracic splenosis as a differential diagnosis of juxtapleural nodules

Thoracic splenosis is rare and consists of ectopic implantation of splenic tissue into the chest after concomitant thoracic and abdominal trauma with diaphragm injury. It occurs in about 18% of cases of splenic ruptures. In almost all cases, diagnosis is given incidentally once patients are usually asymptomatic. Thoracic splenosis should be considered as a differential diagnosis in all patients with history of trauma presenting with juxtapleural nodules in chest computed tomography. However, malignant conditions should be ruled out firstly. Biopsy is not essential for the diagnosis once nuclear medicine can confirm splenosis in patients with pertinent history of trauma and suggestive tomographic image. We present a typical case of thoracic splenosis whose diagnosis was made by nuclear medicine and no invasive procedures were required.

Preliminary structural characterization of human SOUL, a haem-binding protein

Human SOUL (hSOUL) is a 23 kDa haem-binding protein that was first identified as the PP(23) protein isolated from human full-term placentas. Here, the overexpression, purification and crystallization of hSOUL are reported. The crystals belonged to space group P6(4)22, with unit-cell parameters a = b = 145, c = 60 A and one protein molecule in the asymmetric unit. X-ray diffraction data were collected to 3.5 A resolution at the ESRF. A preliminary model of the three-dimensional structure of hSOUL was obtained by molecular replacement using the structures of murine p22HBP (PDB codes 2gov and 2hva), obtained by solution NMR, as search models.

Characterization of Aspergillus flavus strains from Brazilian Brazil nuts and cashew by RAPD and ribosomal DNA analysis

AIMS

The aim of this study was to determine the genetic variability in Aspergillus flavus populations from Brazil nut and cashew and develop a polymerase chain reaction (PCR) detection method.

METHODS AND RESULTS

Chomatography analysis of 48 isolates identified 36 as aflatoxigenic (75%). One hundred and forty-one DNA bands were generated with 11 random amplified polymorphic DNA (RAPD) primers and analysed via unweighted pair group analysis, using arithmetic means (UPGMA). Isolates grouped according to host, with differentiation of those from A. occidentale also according to geographical origin. Aspergillus flavus-specific PCR primers ASPITSF2 and ASPITSR3 were designed from ribosomal DNA internal transcribed spacers (ITS 1 and 2), and an internal amplification control was developed, to prevent false negative results. Specificity to only A. flavus was confirmed against DNA from additional aspergilli and other fungi.

CONCLUSIONS

RAPD-based characterization differentiated isolates according to plant host. The PCR primer pair developed showed specificity to A. flavus, with a detection limit of 10 fg.

SIGNIFICANCE AND IMPACT OF THE STUDY

Genetic variability observed in A. flavus isolates from two Brazilian agroecosystems suggested reproductive isolation. The PCR detection method developed for A. flavus represents progress towards multiplex PCR detection of aflatoxigenic and nonaflatoxigenic strains in Hazard Analysis Critical Control Point systems.

Ultrastructural characteristics of blood cells of juvenile loggerhead sea turtles (Caretta caretta)

Ultrastructural characteristics of erythrocytes, heterophils, eosinophils, lymphocytes, monocytes and thrombocytes of the loggerhead sea turtle (Caretta caretta) were evaluated, using blood samples from 15 healthy juvenile animals. Except for the eosinophils, the rest of the white blood cells from loggerhead turtles had similar ultrastructural characteristics compared with blood cells from other sea turtle species. Eosinophils from loggerhead turtles were homogeneous in size, and no crystalline structures were observed within the granules. This paper provides an ultrastructural characterization of blood cells of loggerhead sea turtles, as a reference for future haematological studies of this species.

Ethylene Polymerization over Transition Metal Supported Catalysts. III. Vanadium

The polymerization of ethylene in the presence of vanadium catalysts supported on zeolite NaY, HY and charcoal was examined. The catalysts were prepared by the incipient wetness method and characterized by a variety of techniques to determine the oxidation state of the vanadium species inside the zeolite. In all the catalysts that were prepared vanadium is not in a single oxidation state. These catalysts were active in the polymerization of ethylene with activities of the order of magnitude 105 gPE/molV.[M].h for the zeolite catalysts and 103 gPE/molV.[M].h for the charcoal systems. No polymer could be obtained in the absence of alkylaluminum or aluminoxane in the experimental conditions used. The kinetics of ethylene polymerization reactions using the vanadium catalysts was studied. A kinetic model based on a proposed mechanism for these reactions was used to fit the experimental data. The application of this model resulted in very good fittings and the kinetic rate constants of each elementary step could be estimated. Since the polyethylene that was produced is closely bound to the zeolite catalysts, the thermal and mechanical properties of the PE/zeolite composites were measured, indicating that the presence of zeolite improved the mechanical properties of the polymers produced.

Morphological and functional characterization of beige mouse adrenomedullary secretory vesicles

We tested whether the giant secretory granules observed in the mast cells of the naturally occurring mutant beige mouse (BM) (C57BL/6N-bg) were also present in the adrenal chromaffin cells. The presence of large chromaffin granules (CG) would be a valuable tool for the study of exocytosis in neuronal tissues. Conversely, the observation of large vesicles within chromaffin cells that are different from CG could indicate that CG are of a different origin than granules of mast cells. Ultrastructural analysis demonstrated the presence of large lysososmal-like vesicles in the BM, and also a discrete increase in the number of CG with diameters larger than 240 nm but not of giant CG. In addition, amperometric measurements of single-event exocytosis, using carbon fiber microelectrodes, showed no differences between the quantal size of secretory events from BM and wildtype or bovine chromaffin cells. Minor but significant differences were found between the kinetics of exocytosis in BM cells andwild-type mouse cells. We conclude that CG, but not the abnormal-sized vesicles found in BM chromaffin cells contribute to the catecholamine secretion and that abnormal secretory granules are not present in adrenergic cell lineage.

Determination of immuno-cross-reactivity between Cryptosporidium parvum and Eimeria spp

Immuno-cross-reactivity between Cryptosporidium parvum and Eimeria spp. was studied by the indirect fluorescent antibody test (IFAT) and Western blot procedure. Thirty-seven sera from asymptomatic (non-diarrheic) cattle, with known coprological (presence-absence of coccidia) and serological data respecting C. parvum, were tested by IFAT using Eimeria oocysts as antigen. Most sera (54%) displayed immunofluorescence around the surface of the Eimeria oocysts. Simultaneously, serum samples from rabbits naturally infected with Eimeria spp. (E. magna, E. intestinalis and E. residua), but free of C. parvum infection, were used to investigate the recognition of C. parvum oocyst antigens by the Western blot procedure. Fractions in the 11.5-94 kDa range, as well as others with molecular masses over 94 kDa, were recognized by sera from rabbits. Sera collected during patency period showed low or moderate reaction with antigenic fractions in the 11.5-25 kDa range. However, 29, 58 and 71 to 75 kDa proteic fractions were moderately or strongly recognized even after rabbits finished oocyst excretion.

Effect of a commercial disinfectant ('Virkon') on mouse experimental infection by Cryptosporidium parvum

Cryptosporidium parvum oocysts obtained from naturally-infected calves were exposed to 1-10% 'Virkon' for 10-360 min, then inoculated intragastrically into coccidium-free neonatal mice. Prevalence and intensity of infection were determined seven days later by examination of intestinal homogenates. Although we were unable to abolish infectivity for the mice, the intensity of infection was considerably reduced after long periods of exposure (up to > 90%, depending on disinfectant concentration), indicating that this product may have some value for disinfection when extended exposure is possible (e.g., soaking laboratory glassware).

Glucose metabolism in the testis of the normal and streptozotocin diabetic rat

In the present work, the metabolism of [U-14C]glucose was studied in the testicular tissue of normal and streptozotocin diabetic rats. The results show that diabetes alters 14CO2 production and 14C incorporation into lipids from [U-14C]glucose. No differences were found in the [14C]proteins and [14C]nucleic acids between experimental groups. Results are discussed in relation to an insulin deficiency and/or an alteration in the hypothalamic-hypophyseal-gonadal axis.

Effects of melatonin treatment and environmental lighting on the ultrastructural appearence, melatonin synthesis, norepinephrine turnover and microtubule protein content of the rat pineal gland

Melatonin administration or exposure of rats to darkness for two weeks induced comparable changes in pineal ultrastructure, compatible with a generalized organ's activation. These include an increased number of ribosomes, procentrioles and microtubules, prominent nucleoli and Golgi apparatus, and annulate lamellae. Melatonin treatment resulted in a dose-dependent increase of hydroxyindole-O-methyl transferase and serotonin-N-acetyltransferase activities. In addition it increased by 85% the colchicine binding capacity of pineal homogenates, an estimation of the microtubule protein content of the gland. Pineal norepinephrine turnover was not affected by melatonin treatment. These data indicate that the pineal itself is a target organ for exogenously administered melatonin. Key words: Pineal gland, melatonin, norepinephrine, tubulin.

Melatonin effects on brain. Interaction with microtubule protein, inhibition of fast axoplasmic flow and induction of crystaloid and tubular formations in the hypothalamus

[3-H]Melatonin administered in vivo in the rat cisterna magna became associated with a vinblastine-precipitable protein. Melatonin treatment decreased microtubule protein content by 44% in the arcuate-median eminence region and by 19% in the remaining hypothalamic block, being without significant effect on the cerebral cortex. Superior cervical gangliectomy but not pinealectomy increased microtubule protein content of the rat hypothalamus. Norepinephrine brought about a significantly greater decrease in hypothalamic microtubule protein levels of ganglionectomized rats than in sham-operated or in ganglionectomized-pinealectomized animals. Melatonin treatment induced in most of the axons ending in the pericapillary zone of the rat median eminence crystaloid and tubular formations. Rapid axonal transport in retinal ganglion cells of rabbits was inhibited to the extent of 71.9 and 87.2% by previous exposure to 1.5 of 15 mu g of melatonin intravitreally; melatonin did not affect retinal protein synthesis in this experimental model. These results suggest that melatonin interacts significantly with microtubule or actin-like protein in brain.

Effects of environmental lighting, superior cervical ganglionectomy and adrenergic drugs on microtubule protein levels of the rat hypothalamus

Bilateral superior cervical ganglionectomy or exposure of rats to light for 10 days resulted in comparable increases in microtubule protein content in the hypothalamus. Administration of norepinephrine, L-dopa or isoproterenol decreased hypothalamic tubulin levels to a greater extent in ganglionectomized rats. A prior injection of phentolamine prevented norepinphrine's effects in intact rats and decreased but did not abolish the effect of the catecholamine in ganglionectomized animals. Phentolamine impaired L-dopa activity in intact and denervated rats as did propranolol; beta-adrenergic blockage impaired the effect of norepinephrine in denervated rats and abolished that of isoproterenol. Phentolamine plus propranolol prevented norepinephrine's effects whereas it only impaired L-dopa activity on hypothalamic tubulin content. The prior administration of actinomycin D blocked the effects of norepinephrine, L-dopa or isoproterenol. Pinealectomy abolished the isoproterenol-induced decrease in microtubule protein content and impaired that following L-dopa. These data suggest that tubulin levels of the rat hypothalamus are controlled by adrenergic transmitter via alpha- and beta-receptors, the latter involving the pineal gland.

Effects of melatonin on neurotransmitter uptake and release by synaptosome-rich homogenates of the rat hypothalamus

Preincubation of synaptosome-rich homogenates of rat hypothalamus with melatonin resulted in significant decreases of norepinephrine, serotonin, dopamine and glutamate uptake. Melatonin inhibition was noncompetitive; apparent Km's of initial uptake processes were: (2.5 +/- 0.3) x 10(-7) M for norepinephrine, (2.6 +/- 0.3) x 10(-7) M for serotonin, (2.4 +/- 0.4) x 10(-7) M for dopamine and (1.0 +/- 0.3) x 10(-7) M for glutamate. Apparent Ki's for melatonin inhibition of transmitter uptake were: 0.64 +/- 0.14 mM (norepinephrine), 0.23 +/- mM (serotonin), 0.51 +/- 0.08 mM (dopamine) and 1.21 +/- 0.10 mM (glutamate). Transmitter release evoked by increasing [K+] in medium to 30 mM was augmented by melatonin in a dose-dependent manner. Maximal effects were observed on serotonin release. Accumulation of 3H-melatonin within synaptosome-rich homogenates did not exhibit differences between 0 and 37 degrees C, indicating that the uptake of the hormone was not an active process. These results suggest that exogenously-administered melatonin may affect neurotransmitter accumulation and release in the hypothalamus by modification of the transmitter uptake mechanism rather than by competition with the transmitter for its uptake pump.