Association between early and current gastro-intestinal symptoms and co-morbidities in children and adolescents with Angelman syndrome.

BACKGROUND: Angelman syndrome (AS) is a neurogenetic disorder that causes severe intellectual disability, expressive language deficits, motor impairment, ataxia, sleep problems, epileptic seizures and a happy disposition. People with AS frequently experience gastrointestinal (GI) symptoms. METHOD: This study used data from the Global Angelman Syndrome Registry to explore the relationship between early and current GI symptoms and co-morbidity in children and adolescents with AS (n = 173). Two groups that experienced a high (n = 91) and a low (n = 82) frequency of GI symptoms were examined in relation to feeding and GI history in infancy, sleep and toileting problems, levels of language and communication and challenging behaviours. Predictors of GI symptoms were then investigated using a series of logistic regressions. RESULTS: This analysis found that constipation and gastroesophageal reflux affected 84% and 64%, of the sample, respectively. The high frequency of GI symptoms were significantly associated with: 'refusal to nurse', 'vomiting', 'arching', 'difficulty gaining weight', gastroesophageal reflux, 'solid food transition', frequency of night-time urinary continence and sleep hyperhidrosis during infancy. GI symptoms were not significantly associated with sleep, toileting, language or challenging behaviours. Significant predictors of high frequency GI symptoms were gastroesophageal reflux and sleep hyperhidrosis. CONCLUSIONS: Future research needs to investigate the association between AS and GI co-morbidity in adults with AS.

Endosymbiotic bacteria in the parasitic ciliate Ichthyophthirius multifiliis.

Endosymbiotic bacteria were identified in the parasitic ciliate Ichthyophthirius multifiliis, a common pathogen of freshwater fish. PCR amplification of DNA prepared from two isolates of I. multifiliis, using primers that bind conserved sequences in bacterial 16S rRNA genes, generated an approximately 1,460-bp DNA product, which was cloned and sequenced. Sequence analysis demonstrated that 16S rRNA gene sequences from three classes of bacteria were present in the PCR product. These included Alphaproteobacteria (Rickettsiales), Sphingobacteria, and Flavobacterium columnare. DAPI (4',6-diamidino-2-phenylindole) staining showed endosymbionts dispersed throughout the cytoplasm of trophonts and, in most, but not all theronts. Endosymbionts were observed by transmission electron microscopy in the cytoplasm, surrounded by a prominent, electron-translucent halo characteristic of Rickettsia. Fluorescence in situ hybridization demonstrated that bacteria from the Rickettsiales and Sphingobacteriales classes are endosymbionts of I. multifiliis, found in the cytoplasm, but not in the macronucleus or micronucleus. In contrast, F. columnare was not detected by fluorescence in situ hybridization. It likely adheres to I. multifiliis through association with cilia. The role that endosymbiotic bacteria play in the life history of I. multifiliis is not known.

Standardization of a broth microdilution susceptibility testing method to determine minimum inhibitory concentrations of aquatic bacteria.

A multiple laboratory study was conducted in accordance with the standards established by the Clinical and Laboratory Standards Institute (CLSI), formerly the National Committee for Clinical Laboratory Standards (NCCLS), for the development of quality control (QC) ranges using dilution antimicrobial susceptibility testing methods for bacterial isolates from aquatic animal species. QC ranges were established for Escherichia coli ATCC 25922 and Aeromonas salmonicida subsp. salmonicida ATCC 33658 when testing at 22, 28 and 35 degrees C (E. coli only) for 10 different antimicrobial agents (ampicillin, enrofloxacin, erythromycin, florfenicol, flumequine, gentamicin, ormetoprim/sulfadimethoxine, oxolinic acid, oxytetracycline and trimethoprim/sulfamethoxazole). Minimum inhibitory concentration (MIC) QC ranges were determined using dry- and frozen-form 96-well plates and cation-adjusted Mueller-Hinton broth. These QC ranges were accepted by the CLSI/NCCLS Subcommittee on Veterinary Antimicrobial Susceptibility Testing in January 2004. This broth microdilution testing method represents the first standardized method for determining MICs of bacterial isolates whose preferred growth temperatures are below 35 degrees C. Methods and QC ranges defined in this study will enable aquatic animal disease researchers to reliably compare quantitative susceptibility testing data between laboratories, and will be used to ensure both precision and inter-laboratory harmonization.

Using intracardiac catheter recordings from the His and proximal coronary sinus to distinguish isthmus conduction block during catheter ablation of type I atrial flutter.

Isthmus conduction block, demonstrated with the use of multipolar catheter recordings, is considered the preferred endpoint for ablation of type I atrial flutter. This study investigated the feasibility of using recordings from the His and coronary sinus (CS) to document isthmus conduction block. Isthmus conduction block was produced with linear radiofrequency (RF) ablation in 27 patients with type I atrial flutter. In 13 patients (group I), RF was delivered until bidirectional isthmus conduction block was demonstrated with multipolar Halo catheter recordings. In 14 patients (group II), RF was delivered during pacing from the lateral isthmus at 600 ms until a reversal in activation of the proximal CS and His occurred. At this point, data from the Halo recordings were reviewed to see if reversal correlated with conduction block; if not, further ablation was performed until block was demonstrated. The initial reversal in His and CS activation during RF energy delivery correlated with isthmus block in only 4 (28.6%) of 14 patients in group II. Additional RF delivery produced isthmus block in the other ten patients resulting in a further increase in the St-CS interval of 35 +/- 20 ms. A His-CS interval of at least -40 ms signified isthmus block with a sensitivity and specificity of 48% and 100%, respectively. Reversal in His-CS activation during pacing from the lateral margin of the isthmus is not specific for the creation of isthmus block. While activation of the proximal CS bipole > 40 ms after activation of the His appears specific for isthmus block, the low sensitivity of this finding limits its clinical use.

Electroanatomic magnetic mapping during ablation of isthmus-dependent atrial flutter.

INTRODUCTION: Although recent studies have demonstrated that the endpoint of isthmus conduction block is superior to that of termination and subsequent inability to induce atrial flutter (AFl), the optimal method for determining isthmus conduction block has not been determined. Electroanatomic magnetic mapping during coronary sinus (CS) pacing may provide a reliable endpoint for AFl ablation. METHODS AND RESULTS: Catheter mapping and ablation was performed in 42 patients with isthmus-dependent AFl. The patients were divided into two groups, based on procedural endpoint: Group I (28 patients) - isthmus conduction block was determined based on multipolar catheter recordings and electroanatomic mapping, and Group II (14 patients) - isthmus conduction block was determined by electroanatomic mapping during CS pacing alone. In Group I, ablation procedures were acutely successful in 25 of 28 patients (89 %). A 100 % concordance between the data presented by multipolar catheter recordings and electroanatomic mapping was noted in determining the presence or absence of isthmus conduction block. In Group II, ablation procedures were acutely successful in 13 of 14 patients, 13 (93 %). After a mean of 16.3+/-3.7 months follow up, there was 1 atrial flutter recurrence in the 38 patients (2.6 %) with demonstrated isthmus block at the end of the procedure. CONCLUSIONS: Electroanatomic magnetic mapping during CS pacing is comparable to the multipolar catheter mapping technique for assessing isthmus conduction block as an endpoint for AFl ablation procedures.

Antidromic reciprocating tachycardia in patients with paraseptal accessory pathways: importance of critical delay in the reentry circuit.

Previous studies in patients with antidromic reciprocating tachycardia (ART) have observed a critical anatomic requirement (> 4 cm) between an antegrade bypass tract limb and a retrograde AV nodal limb. We report two patients with ART utilizing a paraseptal accessory pathway. In both cases, a critical degree of slow conduction within the circuit provides unusual electrophysiologic substrate to overcome the expected anatomical constraints.

The community and orthodontic care. Part II: Community-perceived importance of correcting various dentofacial anomalies. Part III: Community perception of the importance of orthodontic treatment.

Part II. A professionally-managed telephone survey was undertaken to assess the community-perceived importance of correcting various dentofacial anomalies. The sample included 505 respondents, aged eighteen and over, from metropolitan and non-metropolitan households across the state of Victoria. The sample distribution had a 95 per cent confidence limit with a 5 per cent margin of error and closely matched the known population distributions for age, sex and geographical location. This article forms part two of a series. It was found that the correction of functional problems such as "difficulty chewing or speaking" was considered to be very important, regardless of age, sex or geographical area. The correction of other factors such as "top teeth which stick out in front", "bottom teeth which stick out in front" or "crooked or crowded front teeth" was also considered to be important. "Spaced front teeth" was the factor considered least important for correction within all groups. It is interesting to note that, for all factors, correction seemed to be considered more important by females and non-metropolitan respondents than by males and metropolitan respondents, In contrast to previous studies in which it has been suggested that patients seek treatment mainly for reasons of aesthetics, the results of this study have shown a definite community recognition of the importance of functional problems as well. Part III. A professionally-managed telephone survey was undertaken to assess the community's perceptions of the importance of having "straight teeth and a nice smile", to assess if a Medicare (the Australian government health benefit scheme) rebate should be provided for orthodontic treatment and to assess whether respondents had any private health insurance that would help cover the cost of orthodontic treatment. The sample included 505 respondents, aged eighteen and over,, from metropolitan and non-metropolitan households across the state of Victoria. The sample distribution had a 95 per cent confidence limit with a 5 per cent margin of error and closely matched the known population distributions for age, sex and geographical location. It was found that a very large percentage of respondents considered the need for "straight teeth and a nice smile" to be very important. This finding is supported by the many studies showing the importance of facial attractiveness to the lives of all people, young and old. Only a small percentage of respondents indicated that they had any private dental health insurance that would help cover the cost of orthodontic treatment. Efforts should be made to inform those responsible for the planning of orthodontic services in both the public and private sectors of the importance of the community's perceptions of aesthetics, and the large amount of published work that reinforces the impact of facial attractiveness on people's lives.

The community and orthodontic care. Part I: community-perceived need and demand for orthodontic treatment.

A professionally managed telephone survey was undertaken to assess community-perceived need and demand for orthodontic treatment, and to determine the proportion of the community with a history of having some form of orthodontic treatment. The sample included 505 respondents, aged eighteen and over, from metropolitan and non-metropolitan households across the state of Victoria in Australia. The sample distribution had a ninety-five per cent confidence limit with a five per cent margin of error, and closely matched the known population distributions for age, sex and geographical location. From the survey it can be concluded that apparently forty-four per cent of Victorian families include someone who has already received some form of orthodontic treatment. Twenty-five per cent of the survey respondents perceived some need for the treatment of a family member; only fifteen per cent of respondents, however, reported that someone in their family actually wanted treatment. This survey has established baseline values for community perceived need and demand for orthodontic treatment. Use of these values should assist in future resource management within both the public and private sectors.

Parental expression of the chromodomain protein Pdd1p is required for completion of programmed DNA elimination and nuclear differentiation.

Thousands of DNA elimination events occur during somatic differentiation of many ciliated protozoa. In Tetrahymena, the eliminated DNA aggregates into submacronuclear structures containing the protein Pdd1p, a member of the chromodomain family. We disrupted somatic copies of PDD1, eliminating parental expression of the gene early in the sexual phase of the life cycle. Even though zygotic expression, from the undisrupted germline PDD1 copy, is activated before DNA elimination normally occurs, the somatic knockout cells suffer defects in DNA elimination, genome endoduplication, and nuclear resorption, and eventually die, demonstrating that PDD1 is essential and suggesting Pdd1p is directly involved in establishing a chromatin structure required for DNA elimination.

Magnetic electroanatomical mapping for ablation of focal atrial tachycardias.

Uniform success for ablation of focal atrial tachycardias has been difficult to achieve using standard catheter mapping and ablation techniques. In addition, our understanding of the complex relationship between atrial anatomy, electrophysiology, and surface ECG P wave morphology remains primitive. The magnetic electroanatomical mapping and display system (CARTO) offers an on-line display of electrical activation and/or signal amplitude related to the anatomical location of the recorded sites in the mapped chamber. A window of electrical interest is established based on signals timed from an electrical reference that usually represents a fixed electrogram recording from the coronary sinus or the atrial appendage. This window of electrical interest is established to include atrial activation prior to the onset of the P wave activity associated with the site of origin of a focal atrial tachycardia. Anatomical and electrical landmarks are defined with limited fluoroscopic imaging support and more detailed global chamber and more focal atrial mapping can be performed with minimal fluoroscopic guidance. A three-dimensional color map representing atrial activation or voltage amplitude at the magnetically defined anatomical sites is displayed with on-line data acquisition. This display can be manipulated to facilitate viewing from any angle. Altering the zoom control, triangle fill threshold, clipping plane, or color range can all enhance the display of a more focal area of interest. We documented the feasibility of using this single mapping catheter technique for localizing and ablating focal atrial tachycardias. In a consecutive series of 8 patients with 9 focal atrial tachycardias, the use of the single catheter CARTO mapping system was associated with ablation success in all but one patient who had a left atrial tachycardia localized to the medial aspect of the orifice of the left atrial appendage. Only low power energy delivery was used in this patient because of the unavailability of temperature monitoring in the early version of the Navistar catheter, the location of the arrhythmia, and the history of arrhythmia control with flecainide. No attempt was made to limit fluoroscopy time in our study population. Nevertheless, despite data acquisition from 120-320 anatomically distinct sites during global and more detailed focal atrial mapping, total fluoroscopy exposure was typically < 30 minutes and was as little as 12 minutes. The detailed display capabilities of the CARTO system appear to offer the potential of enhancing our understanding of atrial anatomy, atrial activation, and their relationship to surface ECG P wave morphology during focal atrial tachycardias.

Type I atrial flutter ablation guided by a basket catheter.

Bidirectional isthmus conduction block has been associated with a low recurrence rate after atrial flutter ablation. We present the case of a type I, typical or "counterclockwise" atrial flutter ablation guided by stimulation and recordings obtained from a basket catheter, which allowed for constant electrogram recording from splines positioned along the right lateral free wall and septum. After atrial flutter termination with radiofrequency application, the ability to record and stimulate from multiple sites in the atrium using the basket catheter was useful to detect residual bidirectional slow conduction through the isthmus. Complete isthmus block could be documented after additional radiofrequency energy applications.

Implantable cardioverter defibrillator oversensing during periods of rate-related bundle branch block.

A patient with an implantable cardioverter defibrillator (ICD) and a dual chamber pacemaker experienced inappropriate ICD therapies only during periods of rate-dependent right bundle branch block. Analysis of both stored and real-time ICD electrograms was critical to correctly diagnosing the problem and offering a solution.

Sustained bundle branch reentry in a patient with hypertrophic cardiomyopathy and nondilated left ventricle.

Ventricular tachycardia is a well-known complication in patients with hypertrophic cardiomyopathy. We report the case of a patient with hypertrophic cardiomyopathy with easily inducible monomorphic ventricular tachycardia. Electrophysiology study demonstrated that bundle branch reentry was the mechanism of the tachycardia. The tachycardia was rendered non-inducible by radiofrequency ablation of the right bundle branch.

Evolutionary conservation of sequences directing chromosome breakage and rDNA palindrome formation in tetrahymenine ciliates.

Extensive, programmed chromosome breakage occurs during formation of the somatic macronucleus of ciliated protozoa. The cis-acting signal directing breakage has been most rigorously defined in Tetrahymena thermophila, where it consists of a 15-bp DNA sequence known as Cbs, for chromosome breakage sequence. We have identified sequences identical or nearly identical to the T. thermophila Cbs at sites of breakage flanking the germline micronuclear rDNA locus of six additional species of Tetrahymena as well as members of two related genera. Other general features of the breakage site are also conserved, but surprisingly, the orientation and number of copies of Cbs are not always conserved, suggesting the occurrence of germline rearrangement events over evolutionary time. At one end of the T. thermophila micronuclear rDNA locus, a pair of short inverted repeats adjacent to Cbs directs the formation of a giant palindromic molecule. We have examined the corresponding sequences from two other Tetrahymena species. We find the sequence to be partially conserved, as previously implied from analysis of macronuclear rDNA, but of variable length and organization.

Pdd1p, a novel chromodomain-containing protein, links heterochromatin assembly and DNA elimination in Tetrahymena.

During Tetrahymena conjugation, programmed DNA degradation occurs in two separate nuclei. Thousands of germline-specific deletion elements are removed from the genome of the developing somatic macronucleus, and the old parental macronucleus is degraded by an apoptotic mechanism. An abundant polypeptide, Pdd1p (formerly p65), localizes to both of these nuclei at the time of DNA degradation. Here we report that, in developing macronuclei, Pdd1p localizes to electron-dense, heterochromatic structures that contain germline-specific deletion elements. Pdd1p also associates with parental macronuclei during terminal stages of apoptosis. Sequencing of the PDD1 gene reveals it to be a member of the chromodomain family, suggesting a molecular link between heterochromatin assembly and programmed DNA degradation.

The role of adhesion molecules in oral cancer.

Cell-cell and cell-matrix interactions are mediated by adhesion molecules. By altering interactions between epithelial cells, extracellular matrix and leukocytes, changes in adhesion molecule expression can influence tumour development and metastasis. This study compared the adhesion molecule profile of oral squamous cell carcinoma (SCC) with normal buccal mucosa. The pattern of expression of adhesion molecules differed between normal epithelial cells and tumour cells, while leukocytes and endothelial cells adjacent to the tumour showed a pattern common to inflammatory sites. Aberrations in cell adhesion receptors on tumour cells may contribute to the unique biologic behaviour of individual tumours.

Technical performance evaluation of BM/Hitachi 747-200 serum fructosamine assay.

The technical performance of serum fructosamine assay as a short-term index of diabetic control was evaluated by using the BM/Hitachi 747-200 Automatic Analyzer (Boehringer Mannheim Corp). Intra- and interassay precisions (CV) were <2%. Linearity was confirmed up to 1000 micromol/L. Lipemia, produced artificially or from hypertriglyceridemia in vivo, did not interfere with measurement of serum fructosamine concentration. However, hemoglobin (Hb) interfered with measurement substantially at concentrations >15.5 micromol/L, and bilirubin interfered substantially at concentrations >68.4 micromol/L. A normal reference range of up to 282 micromol/L (mean +/- 2SD = 242 +/- 40) was derived from results obtained from 228 nondiabetic subjects. In 222 diabetic subjects, serum fructosamine concentration correlated well with fasting glucose concentration (r = 0.74) and with Hb A1c concentration (r = 0.80). This automated fructosamine assay has the advantages of technical simplicity, low cost, and reduced analytical time compared with the Hb A1c method.

Genome downsizing during ciliate development: nuclear division of labor through chromosome restructuring.

The ciliated protozoa divide the labor of germline and somatic genetic functions between two distinct nuclei. The development of the somatic (macro-) nucleus from the germinal (micro-) nucleus occurs during sexual reproduction and involves large-scale, genetic reorganization including site-specific chromosome breakage and DNA deletion. This intriguing process has been extensively studied in Tetrahymena thermophila. Characterization of cis-acting sequences, putative protein factors, and possible reaction intermediates has begun to shed light on the underlying mechanisms of genome rearrangement. This article summarizes the current understanding of this phenomenon and discusses its origin and biological function. We postulate that ciliate nuclear restructuring serves to segregate the two essential functions of chromosomes: the transmission and expression of genetic information.