Home About us Contact
|
Home About us Contact | ||
|
|
||
Relative Prevalence (relative + prevalence)
Selected AbstractsSpatial variation in population density across the geographical range in helminth parasites of yellow perch Perca flavescensECOGRAPHY, Issue 5 2007Robert Poulin The abundance of a species is not constant across its geographical range; it has often been assumed to decrease from the centre of a species' range toward its margins. The central assumption of this "favourable centre" model is tested for the first time with parasites, using different species of helminth parasites exploiting fish as definitive hosts. Data on prevalence (percentage of hosts that are infected) and abundance (mean no. parasites per host) were compiled for 8 helminth species occurring in 23 populations of yellow perch Perca flavescens, from continental North America. For each parasite species, correlations were computed between latitude and both local prevalence and abundance values. In addition, the relationships between the relative prevalence or abundance in one locality and the distance between that locality and the one where the maximum value was reported, were assessed separately for each species to determine whether abundance tends to decrease away from the presumed centre of the range, where it peaks. For both the cestode Proteocephalus pearsei and the acanthocephalan Leptorhynchoides thecatus, there was a positive relationship between prevalence or abundance and the latitude of the sampled population. There was also a significant negative relationship between relative prevalence and the distance from the locality showing the maximum value in P. pearsei, but no such pattern was observed for the other 7 parasite species. Since this single significant decrease in prevalence with increasing distance from the peak value may be confounded by a latitudinal gradient, it appears that the distribution of abundance in parasites of perch does not follow the favourable centre model. This means that the environmental variables affecting the density of parasites (host availability, abiotic conditions) do not show pronounced spatial autocorrelation, with nearby sites not necessarily providing more similar conditions for the growth of parasite populations than distant sites. [source] Prevalence of yeasts in saliva and root canals of teeth associated with apical periodontitisINTERNATIONAL ENDODONTIC JOURNAL, Issue 4 2002M. W. Egan Abstract Egan MW, Spratt DA, Ng Y-L, Lam JM, Moles DR, Gulabivala K. Prevalence of yeasts in saliva and root canals of teeth associated with apical periodontitis. International Endodontic Journal, 35, 321,329, 2002. Aims To determine: (i) the relative prevalence and diversity of yeasts in salivary and root canal samples from the same patients; and (ii) the clinical factors associated with their presence in saliva and root canals. Methodology Sixty root canal samples from teeth associated apical periodontitis and the corresponding whole unstimulated saliva samples were obtained from 55 patients. The medical history including antibiotic therapy and clinical/radiographic data on the teeth were recorded. The samples were serially diluted and cultured on yeast & fungi-selective sabouraud dextrose agar. Isolates were characterized and speciated by the germ tube formation test, hyphal morphology and a commercial biochemical test kit (Rapid ID32C® system). Results Twenty-three yeast isolates were recovered from 19 saliva samples and eight isolates from six root canal samples. Candida albicans (17/23 & 3/8) and Rodotorula mucilaginosa (2/23 & 4/8) were the most prevalent isolates from saliva and root canal samples. It was significantly (13.8 times) more probable that yeasts would be recovered from root canals when they were also present in the saliva (P = 0.021). The effect of coronal restoration leakage (P = 0.08) and previous root canal treatment (P = 0.123) were equivocal. The history of antibiotic therapy had no association with the presence of yeasts in saliva (OR = 1.1). Conclusions Yeasts occurred relatively infrequently (10%) in root canals. Their presence in root canals was significantly associated with their presence in saliva. The role of yeasts in the initiation and perpetuation of periapical disease remains to be determined. [source] Nevi with site-related atypia: a review of melanocytic nevi with atypical histologic features based on anatomic siteJOURNAL OF CUTANEOUS PATHOLOGY, Issue 10 2008Gregory A. Hosler A subset of melanocytic nevi share features with melanoma and nevi with architectural disorder but are biologically inert and to date do not appear to portend an increased risk for the development of malignancy. These benign nevi with certain atypical histologic features cluster among specific anatomic sites and are thus designated nevi with site-related atypia. We categorize these lesions into four main groups: acral, genital, special site and conjunctival, based on anatomy and relative prevalence of specific atypical histologic features. As the literature and our recognition of these lesions continue to grow, our understanding of their biology has not kept pace. [source] HCV genotypes in Sicily: Is there any evidence of a shift?JOURNAL OF MEDICAL VIROLOGY, Issue 6 2009Paola Pizzillo Abstract The distribution of HCV strains in any area is characterized by a relative prevalence of one genotype, and a number of less prevalent types. In some Western countries a change from the prevalent HCV genotype 1 to genotypes 3 and 4 has been reported in the last decade. In order to assess possible variations of the distribution of HCV genotypes in Sicily, a southern region of Italy, a hospital-based cohort, collected prospectively, of 3,209 subjects with chronic HCV infection was surveyed, comparing the distribution of HCV genotypes during two consecutive periods, from 1997 to 2002 and from 2003 to 2007, according to age and gender. The results show that genotype 1b, which has been historically the most prevalent in Sicily, is still predominant, followed more distantly by genotypes 2 and 3a. However, a cohort effect for these genotypes was seen when comparing the two time periods. Genotype 1b decreased slowly over the last decade, due to the death of the people infected, leading to a proportional increase of the other genotypes. No evidence was found in support of a major increase in the prevalence of other genotypes, such as genotype 4, in relation to migration patterns. J. Med. Virol. 81:1040,1046, 2009. © 2009 Wiley-Liss, Inc. [source] Slow-tonic muscle fibers and their potential innervation in the turtle, Pseudemys (Trachemys) scripta elegansJOURNAL OF MORPHOLOGY, Issue 1 2005Robert J. Callister Abstract A description is provided of the ratio of slow-tonic vs. slow- and fast-twitch fibers for five muscles in the adult turtle, Pseudemys (Trachemys) scripta elegans. The cross-sectional area of each fiber type and an estimation of the relative (weighted) cross-sectional area occupied by the different fiber types are also provided. Two hindlimb muscles (flexor digitorum longus, FDL; external gastrocnemius, EG) were selected on the basis of their suitability for future motor-unit studies. Three neck muscles (the fourth head of testo-cervicis, TeC4; the fourth head of retrahens capitus collique, RCCQ4; transversalis cervicis, TrC) were chosen for their progressively decreasing oxidative capacity. Serial sections were stained for myosin adenosine triphosphatase (ATPase), NADH-diaphorase, and alpha-glycerophosphate dehydrogenase (,-GPDH). Conventional fiber-type classification was then performed using indirect markers for contraction speed and oxidative (aerobic) vs. glycolytic (anaerobic) metabolism: i.e., slow oxidative (SO, including slow-twitch and possibly slow-tonic fibers), fast-twitch, oxidative-glycolytic (FOG), and fast-twitch glycolytic (Fg) fibers. Slow-tonic fibers in the SO class were then revealed by directing the monoclonal antibody, ALD-58 (raised against the slow-tonic fiber myosin heavy chain of chicken anterior latissimus dorsi), to additional muscle cross sections. All five of the tested muscles contained the four fiber types, with the ATPase-stained fibers including both slow-tonic and slow-twitch fibers. The extreme distributions of SO fibers were in the predominately glycolytic TrC vs. the predominately oxidative TeC4 muscle (TrC,SO, 9%; FOG, 20%; Fg, 71% vs. TeC4,SO, 58%: FOG, 16%; Fg, 25%). Across the five muscles, the relative prevalence of slow-tonic fibers (4,47%) paralleled that of the SO fibers (9,58%). TeC4 had the highest prevalence of slow-tonic fibers (47%). The test muscles exhibited varying degrees of regional concentration of each fiber type, with the distribution of slow-tonic fibers paralleling that of the SO fibers. In the five test muscles, fiber cross-sectional area was usually ranked Fg > FOG > SO, and slow-twitch always > slow-tonic. In terms of weighted cross-sectional area, which provides a coarse-grain measure of each fiber type's potential contribution to whole muscle force, all five muscles exhibited a higher Fg and lower SO contribution to cross-sectional area than suggested by their corresponding fiber-type prevalence. This was also the case for the slow-twitch vs. slow-tonic fibers. We conclude that slow-tonic fibers are widespread in turtle muscle. The weighted cross-sectional area evidence suggested, however, that their contribution to force generation is minor except in highly oxidative muscles, with a special functional role, like TeC4. There is discussion of: 1) the relationship between the present results and previous work on homologous neck and hindlimb muscles in other nonmammalian species, and 2) the potential motoneuronal innervation of slow-tonic fibers in turtle hindlimb muscles. J. Morphol. © 2005 Wiley-Liss, Inc. [source] THE AUSTRALIAN AND NEW ZEALAND DIALYSIS WORKFORCE STUDY IN THE INTERNATIONAL CONTEXTJOURNAL OF RENAL CARE, Issue 4 2009Nick Polaschek RN SUMMARY Background: Given increasing demand for renal replacement therapy, this study sought to identify of key workforce issues facing dialysis units, based on a "snapshot" of the current workforce. Methods: A web-based survey of all dialysis unit managers in Australia and New Zealand, in October 2008, about their workforce. Results: A significant minority of dialysis staff in most regions were not registered nurses. Many renal registered nurses worked part-time. Staff/patient ratios in dialysis units varied significantly by region, reflecting the relative prevalence of home therapies. Most dialysis units were generally adequately staffed. The proportion of registered nurses with specific renal qualifications varied significantly by region. Conclusion: The changing character of the workforce in the dialysis unit in the future will require clarification of the relationships between different categories of dialysis staff. Specialty education for nurses needs to be oriented to equipping staff to be effective in their changing work environment. [source] Prevalence and distribution of sensitization to foods in the European Community Respiratory Health Survey: a EuroPrevall analysisALLERGY, Issue 9 2010P. Burney To cite this article: Burney P, Summers C, Chinn S, Hooper R, van Ree R, Lidholm J. Prevalence and distribution of sensitization to foods in the European Community Respiratory Health Survey: a EuroPrevall analysis. Allergy 2010; 65: 1182,1188. Abstract Background:, Reports of adverse reactions to foods are increasing, but there is limited information on the comparative prevalence of sensitization to food allergens using standardized methods. Methods:, Sera from the ,random sample' of young adults seen during the second phase of the European Community Respiratory Health Survey were analysed for IgE against 24 foods using ImmunoCAP. Sera were tested on five food mixes, and subsequently on individual foods in each positive mix. Results:, Sera from 4522 individuals living in 13 countries were tested for at least one food allergen mix. Prevalence of sensitization to any of the 24 food allergens ranged from 24.6% in Portland (USA) to 7.7% in Reykjavik (Iceland). With few exceptions, the relative prevalence of sensitization to different foods was similar in all countries. Sensitization rates to egg, fish and milk were each less than 1%, and the most common sensitizations are not represented in current commercial mixes. The prevalence of sensitization to foods was not related to that of sensitization to aeroallergens but was related to the geometric mean total IgE for the country. Conclusions:, Sensitization to foods is common but highly variable. The relative prevalence of sensitization to different foods is more consistent than would be expected by chance, suggesting that quantity of consumption of specific foods does not determine prevalence. The aetiology of food sensitization is only partly similar to that for aeroallergens but is related to local levels of total IgE. This may provide an important clue to the origins of food sensitization. [source] Sensitization, asthma and allergic disease in young soccer playersALLERGY, Issue 4 2009M. T. Ventura Background:, The aim of this study was to identify the prevalence of allergic disease in young soccer players compared to age-matched students and to evaluate if this prevalence changes as the intensity of training increases. Methods:, A modified ECRHS questionnaire was administered to 194 soccer players divided by age as Beginners (8,11 years), Juniors (12,16 years) and Under 21 (17,20 years) to evaluate the prevalence of allergic diseases and symptoms as well as drug consumption. Subjects with a positive personal history of allergic diseases underwent skin prick and/or patch tests. Age-matched students (n = 136) were used as a control group. Results:, The prevalence of allergic diseases was 34.5% in soccer players and 31.6% in control subjects (n.s.). Skin sensitization to inhalant allergens was detected in 14.4% of symptomatic soccer players and in 19.2% of control students (n.s.). Patch tests were positive in 35.7% of soccer players and 23.0% of controls with allergic dermatitis (n.s.). The prevalence of allergic diseases did not significantly change in relation to the intensity of training. Although the relative prevalence of sensitization to perennial allergens and asthma was less frequent in soccer players than in controls, and the occurrence of exercise-induced bronchoconstriction was similar in the two groups, soccer players used twice as many anti-allergic and anti-asthmatic drugs as control students. Conclusions:, An increasingly intensive training programme is not associated with greater risk of allergic disease in soccer players. Therapy regimens of allergic athletes and exercisers should be monitored more closely to guarantee adequate treatment yet avoid inappropriate drug use and doping practices. [source] Frequency analysis and clinical characterization of different types of spinocerebellar ataxia in Serbian patientsMOVEMENT DISORDERS, Issue 2 2006a T. Draga Abstract The relative frequencies of different spinocerebellar ataxias (SCAs) vary widely among different ethnic groups, presumably due to a founder effect. We investigated the relative prevalence of SCA1,3, 6,8, 12, 17; dentate,rubro,pallidoluysian atrophy; and Friedreich's ataxia (FRDA) in Serbian patients with adult-onset (>20 years of age) hereditary and sporadic SCAs, and compared clinical features of patients with genetically confirmed SCAs. A total of 108 patients from 54 families (38 apparently dominant [ADCA] and 16 apparently recessive) with adult-onset hereditary ataxia and 75 apparently sporadic patients were assessed. Of 38 families with ADCA, 13 (34%) were positive for an expansion in an SCA1 and 5 families (13%) for an expansion in an SCA2 allele. In 20 families (53%), no expansions have been identified in any of the analyzed genes. Gaze palsy, spasticity, and hyperreflexia were significantly more common in SCA1, whereas slow saccades, hypotonia, hyporeflexia, and dystonia prevailed in SCA2 patients. Among the 16 families with an apparently recessive mode of ataxia inheritance, 4 (25%) were identified as having the FRDA mutation. Ataxia-causing mutations were identified in 8 (10.6%) of patients with apparently sporadic adult-onset ataxia. © 2005 Movement Disorder Society [source] Ultraviolet radiation intensity predicts the relative distribution of dermatomyositis and anti,Mi-2 autoantibodies in womenARTHRITIS & RHEUMATISM, Issue 8 2009Lori A. Love Objective Because studies suggest that ultraviolet (UV) radiation modulates the myositis phenotype and Mi-2 autoantigen expression, we conducted a retrospective investigation to determine whether UV radiation may influence the relative prevalence of dermatomyositis and anti,Mi-2 autoantibodies in the US. Methods We assessed the relationship between surface UV radiation intensity in the state of residence at the time of onset with the relative prevalence of dermatomyositis and myositis autoantibodies in 380 patients with myositis from referral centers in the US. Myositis autoantibodies were detected by validated immunoprecipitation assays. Surface UV radiation intensity was estimated from UV Index data collected by the US National Weather Service. Results UV radiation intensity was associated with the relative proportion of patients with dermatomyositis (odds ratio [OR] 2.3, 95% confidence interval [95% CI] 0.9,5.8) and with the proportion of patients expressing anti,Mi-2 autoantibodies (OR 6.0, 95% CI 1.1,34.1). Modeling of these data showed that these associations were confined to women (OR 3.8, 95% CI 1.3,11.0 and OR 17.3, 95% CI 1.8,162.4, respectively) and suggests that sex influences the effects of UV radiation on autoimmune disorders. Significant associations were not observed in men, nor were UV radiation levels related to the presence of antisynthetase or anti,signal recognition particle autoantibodies. Conclusion This first study of the distribution of myositis phenotypes and UV radiation exposure in the US showed that UV radiation may modulate the clinical and immunologic expression of autoimmune disease in women. Further investigation of the mechanisms by which these effects are produced may provide insights into pathogenesis and suggest therapeutic or preventative strategies. [source] Pollen counts in relation to the prevalence of allergic rhinoconjunctivitis, asthma and atopic eczema in the International Study of Asthma and Allergies in Childhood (ISAAC)CLINICAL & EXPERIMENTAL ALLERGY, Issue 12 2003M. L. Burr Summary Background Although pollens are major allergens associated with allergic rhinoconjunctivitis and asthma, there is little information about the relative prevalence of these conditions in populations with different pollen exposures. Objective The purpose of this study was to investigate the relationship between pollen exposure and allergic symptoms among children in different countries. Methods An ecological analysis was conducted to see whether pollen exposure (pollen counts, and duration and severity of pollen seasons) is associated with symptoms of allergic rhinoconjunctivitis, asthma and atopic eczema in 28 centres within 11 countries (nine being in Europe). Data on the prevalence of symptoms in 13,14-year olds were based on the responses to the written questionnaires from the International Study of Asthma and Allergies in Childhood (ISAAC). The analysis was adjusted for gross national product and mean annual relative humidity. Results There was little relationship between pollen exposure and symptom prevalence, except for a significant inverse association between grass pollen counts and lifetime prevalence of the symptoms of allergic rhinitis (P=0.03). Almost all the regression coefficients were negative. The associations were even weaker and all non-significant when the analyses were conducted within countries, using a random intercept fixed slope model, but there was still no evidence of a positive association between pollen exposure and symptoms. Conclusion There is a weak but consistent tendency for the prevalence of allergic symptoms to be inversely associated with pollen exposure. This finding accords with evidence from several countries, suggesting that the prevalence of hayfever and asthma tends to be lower in rural than in urban areas, and lowest among people living on farms. Exposure to allergenic pollen in early life does not appear to increase the risk of acquiring symptoms of respiratory allergy, and may even give some protection against them. [source] The cytochrome P450 aromatase lacking exon 5 is associated with a phenotype of nonclassic aromatase deficiency and is also present in normal human steroidogenic tissuesCLINICAL ENDOCRINOLOGY, Issue 5 2007Carolina M. Pepe Summary Objective, The previously described c655G>A mutation of the human cytochrome P450 aromatase gene (P450aro, CYP19) results in aberrant splicing due to disruption of a donor splice site. To explain the phenotype of partial aromatase deficiency observed in a female patient described with this mutation, molecular consequences of the c655G>A mutation were investigated. Design To investigate whether the c655G>A mutation causes an aberrant spliced mRNA lacking exon 5 (,Ex5), P450aro RNA was analysed from the patient's lymphocytes by reverse transcription polymerase chain reaction (RT-PCR) and by splicing assays performed in Y1 cells transfected with a P450aro ,Ex5 expression vector. Aromatase activity of the c655G>A mutant was predicted by three dimensional (3D) protein modelling studies and analysed in transiently transfected Y1 cells. Exon 5 might be predicted as a poorly defined exon suggesting a susceptibility to both splicing mutations and physiological alternative splicing events. Therefore, expression of the ,Ex5 mRNA was also assessed as a possibly naturally occurring alternative splicing transcript in normal human steroidogenic tissues. Patients An aromatase deficient girl was born with ambiguous genitalia. Elevated serum LH, FSH and androgens, as well as cystic ovaries, were found during prepuberty. At the age of 8·4 years, spontaneous breast development and a 194·6 pmol/l serum oestradiol level was observed. Results The ,Ex5 mRNA was found in lymphocytes of the P450aro deficient girl and her father, who was a carrier of the mutation. Mutant minigene expression resulted in complete exon 5 skipping. As expected from 3D protein modelling, ,Ex5 cDNA expression in Y1 cells resulted in loss of P450aro activity. In addition, the ,Ex5 mRNA was present in placenta, prepubertal testis and adrenal tissues. Conclusions Alternative splicing of exon 5 of the CYP19 gene occurs in the wild type (WT) as well as in the c655G>A mutant. We speculate that for the WT it might function as a regulatory mechanism for aromatization, whereas for the mutant a relative prevalence of the shorter over the full-length protein might explain the phenotype of partial aromatase deficiency. [source] Mutations in GCK and HNF-1, explain the majority of cases with clinical diagnosis of MODY in SpainCLINICAL ENDOCRINOLOGY, Issue 4 2007Itziar Estalella Summary Objective, The aim of this study was to group patients with MODY (maturity-onset diabetes of the young) according to the genetic alterations underlying the disease and to investigate their clinical characteristics. Patients and methods, Molecular analysis of GCK (MODY2), HNF-1, (MODY3), HNF-4, (MODY1) and HNF-1, (MODY5) genes was performed by DNA sequencing in 95 unrelated index probands (47M/48F; mean age 9·9 ± 5·2 years) with clinical diagnosis of MODY. After classification into MODY subtypes according to the genetic alterations, clinical characteristics were compared between the groups. Results, Seventy-six families were shown to carry mutations in GCK (34 of them previously unreported), eight families presented HNF-1, mutations, and a large genomic rearrangement in HNF-1, was found in a family. No alteration was found in HNF-4,. Thus, relative frequencies in the group studied were 80% MODY2, 8·5% MODY3 and 1% MODY5. Comparison of clinical parameters according to genetic status showed significant differences between MODY2 and MODY3 patients in age at diagnosis (9·4 ± 5·4 years vs. 12·7 ± 4·6 years), diagnosis (impaired glucose tolerance vs. diabetes), diagnostic test used (OGTT vs. fasting glucose), treatment (diet and exercise vs. insulin/oral antidiabetic agents) and birth weight (2·96 ± 0·44 kg vs. 3·40 ± 0·67 kg). Conclusion, Almost 90% of the MODY cases in the group studied are explained by mutations in the major genes GCK (MODY2) and HNF-1,(MODY3), although differences in the relative prevalence of each form could be partly due to patient referral bias (paediatric vs. adult). In general, patients with MODY2 were diagnosed at an earlier age in life than MODY3 patients and had a milder form of diabetes. Moreover, the majority of patients with MODY2 mutations were treated with diet whereas half of MODY3 patients received pharmacological treatment. [source] Brief Communications: An Analysis of Migraine Triggers in a Clinic-Based PopulationHEADACHE, Issue 8 2010Diane Andress-Rothrock MS Background., Many migraineurs report attack "triggers," but relatively few published data exist regarding the relative prevalences of individual triggers, variations related to gender, duration of migraine or migraine subtype, or the existence of any regional variations in the prevalences and distributions of triggers. Objective., We sought to determine the prevalence and types of migraine triggers in our clinic population, to determine what influence gender, migraine subtype, or duration of migraine might have on the prevalences and types of triggers reported and to compare our findings with data derived from surveys we previously had conducted involving 2 clinic-based populations and 1 general population sample from other regions of the USA. Methods., We evaluated 200 consecutive new migraine patients referred to our clinic. All patients specifically were queried as to whether they had noted any of 7 specific factors to serve consistently as migraine attack triggers and additionally were surveyed as to whether they might have "other" triggers not listed on the intake questionnaire. Among the other data collected and analyzed were age, gender, age at time of migraine onset, and migraine subtype (ie, episodic vs chronic). Actively cycling females who reported menses as a trigger were questioned as to whether their menstrual migraine (MM) attacks differed from their non-menstrual migraines and, if so, how they differed. Results., One hundred and eighty-two patients (91%) reported at least 1 migraine trigger, and 165 (82.5%) reported multiple triggers. The most common trigger reported (59%) was "emotional stress," followed by "too much or little sleep" (53.5%), "odors" (46.5%), and "missing meals" (39%). Females or subjects of either gender with chronic migraine were no more likely than males or subjects with episodic migraine to report triggers or multiple triggers. Similarly, longer exposure to migraine did not correlate with a higher likelihood of reporting a trigger or multiple triggers. Fifty-three (62%) of 85 actively cycling females reported menses as a trigger, and of the 51 with menstrually related migraine, 34 (67%) reported their MM to be more severe, more refractory to symptomatic therapy or of longer duration than their non-menstrual attacks; 13 (24.5%) of the 53 women with apparent MM reported their MM to be at least occasionally manifested as status migrainosus. The prevalence and type of triggers reported by this predominantly white female population were similar to those reported by clinic-based populations in San Diego, California and Mobile, Alabama, and in a population-based sample of Hispanics in San Diego County. Conclusions., A large majority of migraineurs report migraine attack triggers, and the triggers most commonly reported include emotional stress, a disrupted sleep pattern, and various odors. These findings do not appear to vary according to geographic region or race/ethnicity. Among the triggers, MM appears inclined to provoke headache that is more severe, less amenable to treatment, or longer in duration than headaches that occur at other times during the cycle. (Headache 2010;50:1366-1370) [source] | |||||||||||||||||||||||||