Amelogenesis imperfecta, sensorineural hearing loss, and Beau's lines, a second case report of Heimler's syndrome.
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Amelogenesis Imperfecta↗
Biomedical subjects
L Hunter
Publications and source records attributed to L Hunter.
African Index Medicus--a cooperative undertaking.
Although MEDLINE covers many of the significant medical periodical articles published in developed countries, there is still a considerable amount of medical and health documentation from countries outside the major industrialized areas which is not included. This paper outlines various initiatives to address this, and goes on to describe the setting up, on a cooperative basis, of the African Index Medicus, the problems encountered and progress made. 'Even if we should presume that most of the world's valid, important biomedical information originates in the West--and there is evidence (...) to suggest that this is wilful self delusion--what about at least a minority contribution from the rest? The 2% participation in international scientific discourse allowed by Western indexing services is simply too little to account for the scientific output of 80% of the world.'
Africa↗
Leptin and reproduction.
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Adipose Tissue↗
Non-invasive assessment of brachial artery endothelial vasomotor function: the effect of cuff position on level of discomfort and vasomotor responses.
Non-invasive assessment of brachial artery flow-mediated dilation using cuff occlusion of the arm above or below the elbow to stimulate flow is emerging as a highly useful technique to examine endothelial vasomotor function in human subjects. In anticipation of a large-scale investigation, an important issue is the acceptability of the technique to participants. The purpose of this study was to determine the level of discomfort associated with the technique and compare it to the commonly used procedure of venipuncture. Flow-mediated dilation was determined using cuff occlusion of the arm above the elbow and a blood sample was obtained by standard venipuncture from 54 subjects. The level of discomfort for each procedure was assessed and compared using a visual analogue scale and was found to be extremely low. When the occlusion cuff was positioned above the elbow, the discomfort was slightly more severe (1.9+/-1.9 cm) than venipuncture (1.0+/-1.3 cm, p = 0.003). In 27 subjects, the effect of cuff position (above or below the elbow) was compared: the below the elbow position was associated with a reduction in the percentage increase in flow (570+/-280% versus 900+/-560%, p = 0.005), flow-mediated dilation (6.8+/-3.8% versus 9.8+/-5.7%, p = 0.008) and discomfort (1.6+/-0.8 versus 3.7+/-2.2 cm, p = 0.008). When the cuff was located below the elbow, the level of discomfort was equivalent to that associated with venipuncture. Thus, non-invasive assessment of flow-mediated brachial artery dilation is well tolerated and appears to be suitable for a large-scale study of endothelial function.
Adult↗
Visualization based on the Enzyme Commission nomenclature.
We developed a tool for visualizing data related to protein function, based on the nomenclature defined by the International Enzyme Commission. The method represents the 1327 specific reaction types and three additional levels of abstract classifications in the nomenclature as an interactive graph. Each node and link in the graph can have associated with it stored or computed data values of various types, each of which can be assigned to any of a set of visualization methods, including color, size, various chart types and text. Visualizations can then be interactively created for single nodes, groups of nodes or the entire graph. This visualization tool is particularly useful for exploring the distribution of quantitative attributes across protein function classes. As a test of this tool, we developed a visualization of data measuring the effectiveness of sequence similarity for prediction of EC class. Using this tool, it was possible to rapidly scan hundreds of functional classes, and to correlate predictability from sequence with other attributes, facilitating the generation of hypotheses about the causes of predictive failure.
Amino Acid Sequence↗
Identification of divergent functions in homologous proteins by induction over conserved modules.
Homologous proteins do not necessarily exhibit identical biochemical function. Despite this fact, local or global sequence similarity is widely used as an indication of functional identity. Of the 1327 Enzyme Commission defined functional classes with more than one annotated example in the sequence databases, similarity scores alone are inadequate in 251 (19%) of the cases. We test the hypothesis that conserved domains, as defined in the ProDom database, can be used to discriminate between alternative functions for homologous proteins in these cases. Using machine learning methods, we were able to induce correct discriminators for more than half of these 251 challenging functional classes. These results show that the combination of modular representations of proteins with sequence similarity improves the ability to infer function from sequence over similarity scores alone.
Alcohol Dehydrogenase↗
Leptin and leptin receptor mRNA and protein expression in the murine fetus and placenta.
Leptin is a 167-aa protein that is secreted from adipose tissue and is important in the regulation of energy balance. It also functions in hematopoiesis and reproduction. To assess whether leptin is involved in fetal growth and development we have examined the distribution of mRNAs encoding leptin and the leptin receptor (which has at least six splice variants) in the 14.5-day postcoitus mouse fetus and in the placenta using reverse transcription-PCR and in situ hybridization. High levels of gene expression for leptin, the leptin receptor, and the long splice variant of the leptin receptor with an intracellular signaling domain were observed in the placenta, fetal cartilage/bone, and hair follicles. Receptor expression also was detected in the lung, as well as the leptomeninges and choroid plexus of the fetal brain. Western blotting and immunocytochemistry, using specific antibodies, demonstrated the presence of leptin and leptin receptor protein in these tissues. These results suggest that leptin may play a role in the growth and development of the fetus, both through placental and fetal expression of the leptin and leptin receptor genes. In the fetus, leptin may be multifunctional and have both paracrine and endocrine effects.
Animals↗
Supraoccluding cobalt-chrome onlays in the management of amelogenesis imperfecta in children: a 2-year case report.
Children suffering from the inherited dental anomaly amelogenesis imperfecta frequently present with sensitive, discolored teeth and decreased lower facial height. The aim of treatment is to reduce sensitivity while maintaining the maximum amount of hard tissue possible until the patient reaches an age at which advanced restorative techniques can be used to rehabilitate the dentition. A case is presented in which amelogenesis imperfecta in the mixed dentition was managed by the placement of adhesive cast restorations. These restorations have been in place for 2 years.
Amelogenesis Imperfecta↗
Identifying chimerism in proteins using hidden Markov models of codon usage.
Protein chimerism is a phenomenon involving the combination of multiple ancestral sequences into a single, multi-domain protein through evolution. We propose a novel method for detecting chimeric proteins by analyzing their nucleotide sequence. The method tests for differences in the distributions of synonymous (isoaccepting) codons in different regions of the protein. The test involves the comparison of the ability of varying size hidden Markov models (HMMs) of codon usage to fit the natural sequence, relative to a set of randomized controls. We demonstrate the method on the families of yeast nuclear and mitochondrial amino-acyl tRNA synthetases. The method is potentially useful for the automated screening of entire genomes or large databases.
Amino Acyl-tRNA Synthetases↗
Predicting enzyme function from sequence: a systematic appraisal.
Gapped and ungapped sequence alignment were tested as possible methods to classify proteins into the functional classes defined by the International Enzyme Commission (EC). We exhaustively tested all 15,208 proteins labeled with any EC class in a recent release of the SwissProt database, evaluating all 1,327 relevant EC classes. We effectively tested all possible similarity thresholds that could be used for this assignment through the use of the ROC statistic. Approximately 60% of Enzyme Commission classes containing two or more proteins could not be perfectly discriminated by sequence similarity at any threshold. An analysis of the errors indicates that false positive matches dominate, and that various error mechanisms can be identified, including the multidomain nature of many proteins and polyproteins, convergent evolution, variation in enzyme specificity, and other factors. Many of the putatively false positives are in fact biologically relevant. This work strongly suggests that functional assignment of enzymes should attempt to delimit functionally significant subregions, or domains, before matching to EC classes.
Databases, Factual↗
A 6-month home-usage trial of 0.1% and 0.2% delmopinol mouthwashes (I). Effects on plaque, gingivitis, supragingival calculus and tooth staining.
Delmopinol is a morpholinoethanol derivative which, in mouthrinses used in the absence of normal oral hygiene, has been shown effective in the inhibition of plaque and gingivitis. The aim of this study was to determine the adjunctive oral hygiene benefits and safety of delmopinol rinses when used alongside normal toothcleaning. This 6-month home use study was a placebo-controlled, double-blind, randomised parallel design evaluating 0.1% and 0.2% delmopinol rinses and structured to conform with the ADA Council of Dental Therapeutics guidelines. A total of 450 dentate male and female subjects were recruited who had no relevant medical or pharmacotherapy histories determined from a full medical examination, including haematological and biochemical tests. Subjects had moderate levels of plaque and gingivitis. At baseline, 3 and 6 months subjects were scored for plaque, gingivitis, tooth stain and supragingival calculus, with plaque sampled for microbiological analysis. Additionally, oral mucosal examinations were performed and subjects questioned for adverse symptoms. Baseline special tests were repeated at the end of the study. After baseline examinations, the subjects received a professional prophylaxis, provided with the allocated mouthwash and instructed to use 10-ml volumes for 60 s 2 x daily and where appropriate after toothbrushing and meals. Demographic features of the 3 groups were similar and losses to trial were small. Adverse signs and symptoms included transitory numbness of the tongue, tooth and tongue staining, taste disturbance and rarely mucosal soreness and erosion. All local side-effects were less commonly reported at 6 compared to 3 months and only 6 subjects were withdrawn because of adverse event. No systemic effects attributable to the agent were observed and no significant shifts in haematological or biochemical parameters occurred. All groups showed considerable improvements in oral hygiene and gingival health with some significant differences in favour of 0.2% delmopinol compared to placebo for gingivitis and more particularly plaque. Staining was also significantly increased in the delmopinol groups but not calculus. In the present study, a considerable Hawthorne effect occurred, which must in part explain why only a modestly significant effect was achieved.
Adult↗
Respiratory health in a total very low birthweight cohort and their classroom controls.
AIMS: To compare the respiratory health and function at 8 to 9 years of age of a total population based cohort of 300 very low birthweight (VLBW) children with that of two classroom controls (n = 590) matched for age and sex. STUDY DESIGN: Cohort study with controls. SETTING: Schools throughout Scotland. RESULTS: The VLBW children were more likely than their peers to use an inhaler, to be absent from school, and to be admitted to hospital because of respiratory illness. They were significantly shorter than their classroom controls, but even after adjusting for differences in height, the VLBW children had reduced forced vital capacity (FVC); this was associated with a history of prolonged ventilation (> 28 days) and pneumothorax in the neonatal period. There were no significant differences between the groups in forced expiratory volume in one second (FEV1)/FVC but twice as many (7.9% v 3.7%) of the VLBW children had ratios < 70%, denoting obstructive airways disease. Poor expiratory function was associated with neonatal respiratory distress syndrome, prolonged ventilation, and the need for > 40% oxygen. Exercise induced airway narrowing was increased in VLBW children (odds ratio = 2.0; 95% confidence interval 1.2 to 3.4) and was very little changed by adjustment for inhaler use and exposure to cigarette smoke. CONCLUSIONS: As in other low birthweight cohorts, respiratory morbidity was increased. Unlike previous studies, FVC was more affected than expiratory function in this VLBW population. Our findings support the hypothesis that poorer lung function is associated with very low birth weight, but not with intrauterine growth retardation.
Asthma, Exercise-Induced↗
Circular clustering of protein dihedral angles by Minimum Message Length.
Early work on proteins identified the existence of helices and extended sheets in protein secondary structures, a high-level classification which remains popular today. Using the Snob program for information-theoretic Minimum Message Length (MML) classification, we are able to take the protein dihedral angles as determined by X-ray crystallography, and cluster sets of dihedral angles into groups. Previous work by Hunter and States has applied a similar Bayesian classification method, AutoClass, to protein data with site position represented by 3 Cartesian co-ordinates for each of the alpha-Carbon, beta-Carbon and Nitrogen, totalling 9 co-ordinates. By using the von Mises circular distribution in the Snob program, we are instead able to represent local site properties by the two dihedral angles, phi and psi. Since each site can be modelled as having 2 degrees of freedom, this orientation-invariant dihedral angle representation of the data is more compact than that of nine highly-correlated Cartesian co-ordinates. Using the information-theoretic message length concepts discussed in the paper, such a more concise model is more likely to represent the underlying generating process from which the data came. We report on the results of our classification, plotting the classes in (phi, psi) space; and introducing a symmetric information-theoretic distance measure to build a minimum spanning tree between the classes. We also give a transition matrix between the classes and note the existence of three classes in the region phi approximately -1.09 rad and psi approximately -0.75 rad which are close on the spanning tree and have high inter-transition probabilities. This gives rise to a tight, abundant and self-perpetuating structure.
Computational Biology↗
Outbreak of brucellosis at a United States pork packing plant.
In 1992, the North Carolina Department of Environment, Health, and Natural Resources received 18 case reports of brucellosis from a county health department. All patients had potential exposure to the kill floor of one pork processing plant. A subsequent National Institute for Occupational Safety and Health health hazard evaluation surveyed 154 (99%) of 156 kill floor workers of this plant and found that 30 (19%) had evidence of recent (or persistent) brucellosis. These data show that significant exposure to Brucella is occurring among packing plant workers in North Carolina and suggest that some of the approximately 38,000 production workers in pork processing plants in the United States are at risk of contracting swine brucellosis. Additional measures may need to be taken to prevent occupational exposure to Brucella.
Adult↗
Uvulectomy--the making of a ritual.
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Africa↗
Laband syndrome. Report of two cases, review of the literature, and identification of additional manifestations.
Twenty-six persons with Laband syndrome have been reported in the literature to date. We report two further unrelated cases and suggest that a skeletal anterior open bite and symmetric soft tissue swelling of the vault of the palate be added to the variable features associated with the syndrome. There is clear evidence in the literature of autosomal dominant inheritance but our analysis indicates that in some cases recessive transmission is likely.
Abnormalities, Multiple↗
A study of a pre-brushing mouthrinse as an adjunct to oral hygiene.
A previous clinical screening study demonstrated that a cetylpyridinium chloride (CPC) essential oil mouthrinse inhibited plaque regrowth to a significantly greater extent than a negative control or a triclosan/copolymer rinse when used without toothbrushing. The purpose of this study was to evaluate the same ingredient combination as a pre-brushing rinse over a 6-week period. The study employed a 4 group parallel design with a minimum of 50 subjects per group. Subjects with a minimum baseline plaque index of 1.95 were recruited. The formulations employed were two variations of a CPC/essential oil rinse, a triclosan/copolymer product, and a hydroalcohol negative control. Subjects were rendered plaque free at baseline and then rinsed twice daily before toothbrushing with their allocated product. Plaque was scored at 6 days and 6 weeks. Plaque scores were reduced at 6 days compared to baseline but there were no significant differences between any of the groups. At 6 weeks, plaque scores were significantly lower in both CPC/essential oil groups compared to control. Although both CPC/essential oil groups showed plaque scores which were lower than the triclosan group, in only one of the groups was the difference significant. The triclosan product was not significantly different from control. The results support the previous findings that a CPC/essential oil rinse could be a useful adjunct to oral hygiene when used prior to normal toothbrushing.
Adolescent↗
Speakers and listeners: some problems of generalising from a common speech pathology research design.
Experimental studies of speech and language behaviour often have difficulty measuring the phenomena that they seek to investigate. A common solution has been to collect data in the form of listeners' judgements of the speech of members of a clinical group of interest. If the speakers are taken to be a random sample of the clinical group and the listeners a random sample of those who they may communicate with, it is tempting to believe that results from such studies may be generalised to both other speakers and listeners, thus allowing a general statement about the communicative abilities of the clinical group to be made. Two related problems with this form of design are discussed. Both lead to the conclusion that greater caution is required in the interpretation of studies in which listeners' judgements of speakers are analysed. Potential solutions to the problem are offered.
Communication Disorders↗