bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microdebriders Used in Functional Endoscopic Sinus Surgery: Secondary Analysis and Validation of a New Tissue Model
Authors: Dave Sandeep P. , Polak Marek , Casiano Roy R. 
Published: September 2005

AbstractObjectives/Hypothesis: To validate a previously reported in vitro tissue model for microdebrider comparison and determine which microdebrider, tissue type, blade type, and suction strength is most efficient. Specifically, the goal of the secondary analysis is to expand on the results of the preliminary analy‐sis by increasing the sample size, and introduce an aspiration efficiency score (AES) to facilitate microdebrider comparison.Study Design: Prospective randomized comparison.Methods: A prospective randomized comparison of the Diego Powered Dissector and XPS 3000 Powered ENT System was conducted using a soft tissue and a firm tissue model. In addition to evaluating tissue aspiration with straight and angled blades, clogging rates and clearance times were measured. Both standard wall suction and liposuction were used. Basic statistical analysis, a one‐way analysis of variance, and a post hoc Student's t test were performed to compare outcomes.Results: With standard wall suction, the microdebriders were equivalent for the overall microdebrider comparison. For the “head to head” comparison with standard wall suction, the devices were also equivalent when using the straight blades, but the XPS 3000 aspirated more tissue when using the angled blades. With liposuction, the XPS 3000 and liposuction independently aspirated more tissue but clogged more often compared with the Diego PD and regular suction. The aspiration efficiency of soft tissue (oysters) and straight blades was superior compared with firm tissue (scallops) and angled blades. For the “head to head” comparison with liposuction, the XPS 3000 aspirated more tissue regardless of tissue type, but the Diego PD clogged less with firm tissue (scallops). Overall, the AES favored the XPS 3000, soft tissue (oysters), straight blades, and liposuction.Conclusion: Our tissue model represents a reliable and reproducible means of microdebrider comparison. Statistically significant differences between the Diego PD and XPS 3000, as well as between tissue types, blade types, and suction strengths, are reported. Using these results, microdebrider manufacturers can adopt similar tissue models, expand on the current AES, and include other commercially available microdebrider devices to test and report product performance to the consumer. Perhaps an optimal open to closed ratio or liposuction pressure can be determined that yields the greatest tissue aspiration with the fewest number of clogs.
Clinical Features of Sudden Sensorineural Hearing Loss in Diabetic Patients
Authors: Weng Shuen‐Fu , Chen Yuh‐Shyang , Hsu Chuan‐Jen , Tseng Fen‐Yu 
Published: September 2005

AbstractObjectives: Clinical studies of sudden sensorineural hearing loss (SSNHL) rarely focus on diabetic patients. We attempted to elucidate the clinical features of SSNHL in diabetic patients and to evaluate the factors influencing hearing deficits.Study Design: Retrospective.Methods: A retrospective review of diabetic patients with SSNHL was conducted at National Taiwan University Hospital from 1984 to 2003. The demographic and clinical characteristics, audiometries, and course of hearing recovery were reviewed.Results: Sixty‐seven patients (38 men and 29 women) with a mean age of 60.1 ±11.9 years were recruited. The mean duration of diabetes was 7. 5 ± 7.7 years. The mean fasting plasma glucose (FPG), postprandial plasma glucose (PPG), and glycosylated hemoglobin (HbA1C) at admission were 12.4 ± 5.3 mmol/L, 14.5 ± 5.4 mmol/L, and 9.9 ± 2.9 mmol/L, respectively. Profound hearing loss was very common in this series (44.8%). Hearing impairment was also noted in the opposite ear, especially in the high frequencies. Presenting symptoms, the duration of diabetes, the FPG, and the HbA1C had no significant correlations with the severity of hearing loss. After adjusting for sex and age, a high PPG level was significantly associated with opposite‐ear hearing deficits in the middle frequencies. In follow‐up, the low and middle tone hearing thresholds in the lesion ears improved more than that at high frequencies, but they still did not return to baseline. Hearing consistently improved within 2 months after disease onset, but improvements were rare thereafter. With suitable treatment, optimal glycemic control could be achieved even under high‐dose steroid regimens.Conclusions: In diabetic patients with SSNHL, hearing loss in the contralateral ear and the profound type hearing loss in the lesion ear were commonly noted. The age and PPG level had significant correlations to contra‐ear hearing loss. The poor prognosis of sudden deafness in diabetes patients may be caused by preexisting microvascular lesions in the inner ear, and the PPG level could be a risk factor indicator for cochlear dysfunction in diabetic patients. High‐dose glucocorticoid should not be contraindicant in diabetic patients with SSNHL. Whether a longer duration of treatment will result in more hearing improvement is worthy of further study.
Management of Contralateral N0 Neck in Tonsillar Squamous Cell Carcinoma
Authors: Lim Young Chang , Lee Sei Young , Lim Jae‐Yol , Shin Hyang Ae , Lee Jin Seok , Koo Bon Seok , Kim Se‐Heon , Choi Eun Chang 
Published: September 2005

AbstractObjectives: It is well established that tonsillar squamous cell carcinomas have a high probability of disseminating to the neck. An ipsilateral neck treatment is mandatory during initial treatment of stages II to IV tonsillar carcinomas. However, as of yet, no consensus exists whether to perform elective contralateral neck management.Materials and Methods: A retrospective analysis of 43 N0‐3 tonsillar cancer patients with contralateral clinically negative necks from 1992 to 2002 was performed. All patients had a contralateral elective neck dissection. Surgical treatment was followed by postoperative radiotherapy in 33 patients. The follow‐up period ranged from 2 to 120 (mean 38) months. The Kaplan‐Meier method and log‐rank test were used to calculate the disease‐specific survival rates and prognostic significance of contralateral occult lymph node metastasis.Results: Clinically negative, but pathologically positive, contralateral lymph nodes occurred in 16% (7 of 43). Of the 33 cases with an ipsilateral node positive neck, contralateral occult lymph node metastases developed in 21% (7 of 33), in contrast with 0% in ipsilateral N0 necks. On the basis of the clinical staging of the tumor, 5% (1 of 22) of the cases showed lymph node metastases in T2 tumors, 36% (5 of 14) in T3, and 25% (1 of 4) in T4. None of the T1 tumors (3 cases) had pathologically positive lymph nodes (T1 + T2 vs. T3 + T4, P < .05). Patients with no evidence of contralateral nodal cancer had significantly improved disease‐specific survival over patients with any pathologically positive nodes (5 year disease‐specific survival rate 92% vs. 28%, P = < .05).Conclusion: The risk of contralateral occult neck involvement in above T3 staged tonsillar squamous cell carcinomas with unilateral metastases was high (approximately 21%), and patients who present with a contralateral metastatic neck have a worse prognosis than those who are staged as N0. Therefore, we advocate an elective contralateral neck treatment in tonsillar squamous cell carcinoma patients with ipsilateral node metastases.
Psb29, a Conserved 22-kD Protein, Functions in the Biogenesis of Photosystem II Complexes in Synechocystis and Arabidopsis
Authors: Keren Nir , Ohkawa Hiroshi , Welsh Eric A. , Liberton Michelle , Pakrasi Himadri B. 
Published: September 2005

Abstract
Photosystem II (PSII), the enzyme responsible for photosynthetic oxygen evolution, is a rapidly turned over membrane protein complex. However, the factors that regulate biogenesis of PSII are poorly defined. Previous proteomic analysis of the PSII preparations from the cyanobacterium Synechocystis sp PCC 6803 detected a novel protein, Psb29 (Sll1414), homologs of which are found in all cyanobacteria and vascular plants with sequenced genomes. Deletion of psb29 in Synechocystis 6803 results in slower growth rates under high light intensities, increased light sensitivity, and lower PSII efficiency, without affecting the PSII core electron transfer activities. A T-DNA insertion line in the PSB29 gene in Arabidopsis thaliana displays a phenotype similar to that of the Synechocystis mutant. This plant mutant grows slowly and exhibits variegated leaves, and its PSII activity is light sensitive. Low temperature fluorescence emission spectroscopy of both cyanobacterial and plant mutants shows an increase in the proportion of uncoupled proximal antennae in PSII as a function of increasing growth light intensities. The similar phenotypes observed in both plant and cyanobacterial mutants demonstrate that the function of Psb29 has been conserved throughout the evolution of oxygenic photosynthetic organisms and suggest a role for the Psb29 protein in the biogenesis of PSII.
SUPPRESSOR OF FRIGIDA3Encodes a Nuclear ACTIN-RELATED PROTEIN6 Required for Floral Repression inArabidopsis w⃞
Authors: Choi Kyuha , Kim Sanghee , Kim Sang Yeol , Kim Minsoo , Hyun Youbong , Lee Horim , Choe Sunghwa , Kim Sang-Gu , Michaels Scott , Lee Ilha 
Published: September 2005

AbstractFlowering traits in winter annual Arabidopsis thaliana are conferred mainly by two genes, FRIGIDA (FRI) and FLOWERING LOCUS C (FLC). FLC acts as a flowering repressor and is regulated by multiple flowering pathways. We isolated an early-flowering mutant, suppressor of FRIGIDA3 (suf3), which also shows leaf serration, weak apical dominance, and infrequent conversion of the inflorescence shoot to a terminal flower. The suf3 mutation caused a decrease in the transcript level of FLC in both a FRI-containing line and autonomous pathway mutants. However, suf3 showed only a partial reduction of FLC transcript level, although it largely suppressed the late-flowering phenotype. In addition, the suf3 mutation caused acceleration of flowering in both 35S-FLC and a flc null mutant, indicating that SUF3 regulates additional factor(s) for the repression of flowering. SUF3 is highly expressed in the shoot apex, but the expression is not regulated by FRI, autonomous pathway genes, or vernalization. SUF3 encodes the nuclear ACTIN-RELATED PROTEIN6 (ARP6), the homolog of which in yeast is a component of an ATP-dependent chromatin-remodeling SWR1 complex. Our analyses showed that SUF3 regulates FLC expression independent of vernalization, FRI, and an autonomous pathway gene, all of which affect the histone modification of FLC chromatin. Subcellular localization using a green fluorescent protein fusion showed that Arabidopsis ARP6 is located at distinct regions of the nuclear periphery.
The Flowering Integrator FT RegulatesSEPALLATA3andFRUITFULLAccumulation inArabidopsisLeaves
Authors: Teper-Bamnolker Paula , Samach Alon 
Published: September 2005

AbstractThe transition to flowering involves major changes in the shoot apical meristem and in the fate of existing leaf primordia. Transcripts of the Arabidopsis thaliana flowering-promoting gene FLOWERING LOCUS T (FT) are present in leaf tissue but can also promote flowering when artificially introduced into the meristem. FT may normally act in the leaf and/or the meristem, initiating or constituting a mobile flower-promoting signal. We studied FT-dependent events in the rosette leaf, some of which might precede or mimic events in the meristem and its primordia. We show FT-dependent transcript accumulation of the MADS box transcription factors FRUITFULL (FUL) and SEPALLATA3 (SEP3) in leaves. Abnormally high levels of FT further increase the expression of these genes, leading to morphological changes in the leaves. Loss of the flowering-time gene FD, as well as environmental conditions that delay flowering, reduce FT's effect on leaves via reduced activation of its targets. FUL, SEP3, and APETALA1 accumulation in the meristem is associated with and contributes to the transition to flowering. We propose that FT functions through partner-dependent transcriptional activation of these and as-yet-unknown genes and that this occurs at several sites. Organ fate may depend on both degree of activation and the developmental stage reached by the organ before activation occurs.
Prediction of protein thermostability with a direction‐ and distance‐dependent knowledge‐based potential
Authors: Hoppe Christian , Schomburg Dietmar 
Published: September 2005

AbstractThe increasing use of enzymes in industrial processes and the importance of understanding protein folding and stability have led to several attempts to predict and quantify the effect of every possible amino acid exchange (mutation) on the thermostability of proteins. In this article we describe a knowledge‐based discrimination function that acts as a fast and reliable guide in protein engineering and optimization. The function used consists of two parts, a pairwise energy function based on a distance‐ and direction‐dependent atomic description of the amino acid environment, and a torsion angle energy function. In a first step a training set of 11 proteins including 646 mutant proteins with experimentally determined thermostability was used to optimize the knowledge‐based energy functions. The resulting potential function was then tested using a test mutant database consisting of 918 various point mutations introduced in 27 proteins. The best correlation coefficient obtained for the experimental data and the predicted thermostability for the training set is r = 0.81 (561 data points). A total of 76% of the mutations could be predicted correctly as being either stabilizing or destabilizing. The results for the test set are r = 0.74 (747 data points) and 72%, respectively. The global correlation over the combined data (1308 mutants) obtained is 0.78.
Three‐state protein folding: Experimental determination of free‐energy profile
Authors: Baryshnikova Ekaterina N. , Melnik Bogdan S. , Finkelstein Alexei V. , Semisotnov Gennady V. , Bychkova Valentina E. 
Published: September 2005

AbstractWhen considering protein folding with a transient intermediate, a difficulty arises as to determination of the rates of separate transitions. Here we overcome this problem, using the kinetic studies of the unfolding/refolding reactions of the three‐state protein apomyoglobin as a model. Amplitudes of the protein refolding kinetic burst phase corresponding to the transition from the unfolded (U) to intermediate (I) state, that occurs prior to the native state (N) formation, allow us to estimate relative populations of the rapidly converting states at various final urea concentrations. On the basis of these proportions, a complicated experimental chevron plot has been deconvolved into the urea‐dependent rates of the I↔N and U↔N transitions to give the dependence of free energies of the main transition state and of all three (N, I, and U) stable states on urea concentration.
Effect of hexafluoroisopropanol alcohol on the structure of melittin: A molecular dynamics simulation study
Authors: Roccatano Danilo , Fioroni Marco , Zacharias Martin , Colombo Giorgio 
Published: September 2005

AbstractThe molecular mechanism by which HFIP stabilizes the α‐helical structure of peptides is not well understood. In the present study, we use melittin as a model to gain insight into the details of the atomistic interactions of HFIP with the peptide. We have performed extensive comparative molecular dynamics simulations (up to 100 nsec) in the absence and in the presence of HFIP. In agreement with recent NMR experiments, the simulations show rapid loss of tertiary structure in water at pH 2 but much higher helicity in 35% HFIP. The MD simulations also indicate that melittin adopts a highly dynamic global structure in 35% HFIP solution with two α‐helical segments sampling a wide range of angular orientations. The analysis of the HFIP distribution shows the tendency of HFIP to aggregate around the peptide, increasing the local cosolvent concentration to more than two times that in the bulk concentration. The correlation of local peptide structure with HFIP coating suggests that displacement of water at the peptide surface is the main contribution of HFIP in stabilizing the secondary structure of melittin. Finally, a stabilizing effect promoted by the presence of counter‐ions was also observed in the simulations.
Organism complexity anti‐correlates with proteomic β‐aggregation propensity
Authors: Tartaglia Gian Gaetano , Pellarin Riccardo , Cavalli Andrea , Caflisch Amedeo 
Published: September 2005

AbstractWe introduce a novel approach to estimate differences in the β‐aggregation potential of eukaryotic proteomes. The approach is based on a statistical analysis of the β‐aggregation propensity of polypeptide segments, which is calculated by an equation derived from first principles using the physicochemical properties of the natural amino acids. Our analysis reveals a significant decreasing trend of the overall β‐aggregation tendency with increasing organism complexity and longevity. A comparison with randomized proteomes shows that natural proteomes have a higher degree of polarization in both low and high β‐aggregation prone sequences. The former originates from the requirement of intrinsically disordered proteins, whereas the latter originates from the necessity of proteins with a stable folded structure.
Crystal lattice as biological phenotype for insect viruses
Authors: Anduleit Karin , Sutton Geoff , Diprose Jonathan M. , Mertens Peter P.C. , Grimes Jonathan M. , Stuart David I. 
Published: September 2005

AbstractMany insect viruses survive for long periods by occlusion within robust crystalline polyhedra composed primarily of a single polyhedrin protein. We show that two different virus families form polyhedra which, despite lack of sequence similarity in the virally encoded polyhedrin protein, have identical cell constants and a body‐centered cubic lattice. It is almost inconceivable that this could have arisen by chance, suggesting that the crystal lattice has been preserved because it is particularly well‐suited to its function of packaging and protecting viruses.
Structural characterization of Lyn‐SH3 domain in complex with a herpesviral protein reveals an extended recognition motif that enhances binding affinity
Authors: Bauer Finn , Schweimer Kristian , Meiselbach Heike , Hoffmann Silke , Rösch Paul , Sticht Heinrich 
Published: September 2005

AbstractThe Src homology 3 (SH3) domain of the Src family kinase Lyn binds to the herpesviral tyrosine kinase interacting protein (Tip) more than one order of magnitude stronger than other closely related members of the Src family. In order to identify the molecular basis for high‐affinity binding, the structure of free and Tip‐bound Lyn‐SH3 was determined by NMR spectroscopy. Tip forms additional contacts outside its classical proline‐rich recognition motif and, in particular, a strictly conserved leucine (L186) of the C‐terminally adjacent sequence stretch packs into a hydrophobic pocket on the Lyn surface. Although the existence of this pocket is no unique property of Lyn‐SH3, Lyn is the only Src family kinase that contains an additional aromatic residue (H41) in the n‐Src loop as part of this pocket. H41 covers L186 of Tip by forming tight hydrophobic contacts, and model calculations suggest that the increase in binding affinity compared with other SH3 domains can mainly be attributed to these additional interactions. These findings indicate that this pocket can mediate specificity even between otherwise closely related SH3 domains.
Solution structure of a late embryogenesis abundant protein (LEA14) from Arabidopsis thaliana, a cellular stress‐related protein
Authors: Singh Shanteri , Cornilescu Claudia C. , Tyler Robert C. , Cornilescu Gabriel , Tonelli Marco , Lee Min S. , Markley John L. 
Published: September 2005

AbstractWe report the three‐dimensional structure of a late embryogenesis abundant (LEA) protein from Arabidopsis thaliana gene At1g01470.1. This protein is a member of Pfam cluster PF03168, and has been classified as a LEA14 protein. LEA proteins are expressed under conditions of cellular stress, such as desiccation, cold, osmotic stress, and heat. The structure, which was determined by NMR spectroscopy, revealed that the At1g01470.1 protein has an αβ‐fold consisting of one α‐helix and seven β‐strands that form two antiparallel β‐sheets. The closest structural homologs were discovered to be fibronectin Type III domains, which have <7% sequence identity. Because fibronectins from animal cells have been shown to be involved in cell adhesion, cell motility, wound healing, and maintenance of cell shape, it is interesting to note that in plants wounding or stress results in the overexpression of a protein with fibronectin Type III structural features.
In vitro study of stability and amyloid‐fibril formation of two mutants of human stefin B (cystatin B) occurring in patients with EPM1
Authors: Rabzelj Sabina , Turk Vito , Žerovnik Eva 
Published: September 2005

AbstractMyoclonus epilepsy of type 1 (EPM1) is a rare monogenic progressive and degenerative epilepsy, also known under the name Unverricht‐Lundborg disease. With the aim of comparing their behavior in vitro, wild‐type (wt) human stefin B (cystatin B) and the G4R and the R68X mutants observed in EPM1 were expressed and isolated from the Escherichia coli lysate. The R68X mutant (Arg68Stop) is a peptide of 67 amino acids from the N terminus of stefin B. CD spectra have shown that the R68X peptide is not folded, in contrast to the G4R mutant, which folds like wild type. The wild type and the G4R mutant were unfolded by urea and by trifluoroethanol (TFE). It has been shown that both proteins have closely similar stability and that at pH 4.8, where a native‐like intermediate was demonstrated, TFE induces unfolding intermediates prior to the major transition to the all‐α‐helical state. Kinetics of fibril formation were followed by Thioflavin T fluorescence while the accompanying changes of morphology were followed by the transmission electron microscopy (TEM). For the two folded proteins the optimal concentration of TFE producing extensive lag phases and high fibril yields was predenaturational, 9% (v/v). The unfolded R68X peptide, which is highly prone to aggregate, formed amyloid fibrils in aqueous solution and in predenaturing 3% TFE. The G4R mutant exhibited a much longer lag phase than the wild type, with the accumulation of prefibrillar aggregates. Implications for pathology in view of the higher toxicity of prefibrillar aggregates to cells are discussed.
COG3926 and COG5526: A tale of two new lysozyme‐like protein families
Authors: Pei Jimin , Grishin Nick V. 
Published: September 2005

AbstractWe have identified two new lysozyme‐like protein families by using a combination of sequence similarity searches, domain architecture analysis, and structural predictions. First, the P5 protein from bacteriophage ϕ8, which belongs to COG3926 and Pfam family DUF847, is predicted to have a new lysozyme‐like domain. This assignment is consistent with the lytic function of P5 proteins observed in several related double‐stranded RNA bacteriophages. Domain architecture analysis reveals two lysozyme‐associated transmembrane modules (LATM1 and LATM2) in a few COG3926/DUF847 members. LATM2 is also present in two proteins containing a peptidoglycan binding domain (PGB) and an N‐terminal region that corresponds to COG5526 with uncharacterized function. Second, structure prediction and sequence analysis suggest that COG5526 represents another new lysozyme‐like family. Our analysis offers fold and active‐site assignments for COG3926/DUF847 and COG5526. The predicted enzymatic activity is consistent with an experimental study on the zliS gene product from Zymomonas mobilis, suggesting that bacterial COG3926/DUF847 members might be activators of macromolecular secretion.