Phobic anxiety in 11 nations. Part I: Dimensional constancy of the five-factor model.

The Fear Survey Schedule-III (FSS-III) was administered to a total of 5491 students in Australia, East Germany, Great Britain, Greece, Guatemala, Hungary, Italy, Japan, Spain, Sweden, and Venezuela, and submitted to the multiple group method of confirmatory analysis (MGM) in order to determine the cross-national dimensional constancy of the five-factor model of self-assessed fears originally established in Dutch, British, and Canadian samples. The model comprises fears of bodily injury-illness-death, agoraphobic fears, social fears, fears of sexual and aggressive scenes, and harmless animals fears. Close correspondence between the factors was demonstrated across national samples. In each country, the corresponding scales were internally consistent, were intercorrelated at magnitudes comparable to those yielded in the original samples, and yielded (in 93% of the total number of 55 comparisons) sex differences in line with the usual finding (higher scores for females). In each country, the relatively largest sex differences were obtained on harmless animals fears. The organization of self-assessed fears is sufficiently similar across nations to warrant the use of the same weight matrix (scoring key) for the FSS-III in the different countries and to make cross-national comparisons feasible. This opens the way to further studies that attempt to predict (on an a priori basis) cross-national variations in fear levels with dimensions of national cultures.

Infections with Ehrlichia chaffeensis and Ehrlichia ewingii in persons coinfected with human immunodeficiency virus.

The clinical course and laboratory evaluation of 21 patients coinfected with human immunodeficiency virus (HIV) and Ehrlichia chaffeensis or Ehrlichia ewingii are reviewed and summarized, including 13 cases of ehrlichiosis caused by E. chaffeensis, 4 caused by E. ewingii, and 4 caused by either E. chaffeensis or E. ewingii. Twenty patients were male, and the median CD4(+) T lymphocyte count was 137 cells/microL. Exposures to infecting ticks were linked to recreational pursuits, occupations, and peridomestic activities. For 8 patients, a diagnosis of ehrlichiosis was not considered until > or =4 days after presentation. Severe manifestations occurred more frequently among patients infected with E. chaffeensis than they did among patients infected with E. ewingii, and all 6 deaths were caused by E. chaffeensis. Ehrlichiosis may be a life-threatening illness in HIV-infected persons, and the influence of multiple factors, including recent changes in the epidemiology and medical management of HIV infection, may increase the frequency with which ehrlichioses occur in this patient cohort.

PCR amplification and phylogenetic analysis of groESL operon sequences from Ehrlichia ewingii and Ehrlichia muris.

Broad-range PCR primers were used to amplify part of the groESL operon of the canine pathogen Ehrlichia ewingii, recently recognized as a human pathogen, and the murine pathogen Ehrlichia muris. Phylogenetic analysis supported the relationships among Ehrlichia species previously determined by comparison of 16S rRNA gene sequences. These sequences provide additional PCR targets for species for which few gene sequences have been determined.

Changes in levels of dental anxiety as a function of dental experience.

From the literature, it is increasingly apparent that dentally anxious individuals are not a homogeneous group and that the development and maintenance of dental anxiety are complex phenomena. In this study, individuals who had avoided dental treatment in the past due to fear but were no longer fearful were compared with others who had avoided and were still fearful on a number of demographic, experiential, and attitudinal variables under the assumption that avoidance is likely to prevent the emotional processing of dental anxiety. The groups differed markedly in their experience of dentistry; anxious avoiders were more likely to have experienced more invasive and less noninvasive dental treatment; they feared pain more and were more negative about dentistry than those whose anxiety had remitted. In addition, the remitted avoiders were less likely to claim frightening or embarrassing dental experiences as well as being less reactive to these experiences than the others.

Ehrlichia ewingii, a newly recognized agent of human ehrlichiosis.

BACKGROUND: Human ehrlichiosis is a recently recognized tick-borne infection. Four species infect humans: Ehrlichia chaffeensis, E. sennetsu, E. canis, and the agent of human granulocytic ehrlichiosis. METHODS: We tested peripheral-blood leukocytes from 413 patients with possible ehrlichiosis by broad-range and species-specific polymerase-chain-reaction (PCR) assays for ehrlichia. The species present were identified by species-specific PCR assays and nucleotide sequencing of the gene encoding ehrlichia 16S ribosomal RNA. Western blot analysis was used to study serologic responses. RESULTS: In four patients, ehrlichia DNA was detected in leukocytes by a broad-range PCR assay, but not by assays specific for E. chaffeensis or the agent of human granulocytic ehrlichiosis. The nucleotide sequences of these PCR products matched that of E. ewingii, an agent previously reported as a cause of granulocytic ehrlichiosis in dogs. These four patients, all from Missouri, presented between May and August 1996, 1997, or 1998 with fever, headache, and thrombocytopenia, with or without leukopenia. All had been exposed to ticks, and three were receiving immunosuppressive therapy. Serum samples obtained from three of these patients during convalescence contained antibodies that reacted with E. chaffeensis and E. canis antigens in a pattern different from that of humans with E. chaffeensis infection but similar to that of a dog experimentally infected with E. ewingii. Morulae were identified in neutrophils from two patients. All four patients were successfully treated with doxycycline. CONCLUSIONS: These findings provide evidence of E. ewingii infection in humans. The associated disease may be clinically indistinguishable from infection caused by E. chaffeensis or the agent of human granulocytic ehrlichiosis.

Age of onset of dental anxiety.

Little attention has been given to the issue of the age of onset of dental anxiety, even though it may have a bearing on the origins of this type of fear. This study aimed to identify the age of onset of dental anxiety and to identify differences by age of onset with respect to potential etiological factors, such as negative dental experiences, family history of dental anxiety, and general psychological states. Data were collected by means of two mail surveys of a random sample of the adult population. Of 1420 subjects returning questionnaires, 16.4% were dentally anxious. Half, 50.9%, reported onset in childhood, 22.0% in adolescence, and 27.1% in adulthood. Logistic regression analyses indicated that negative dental experiences were predictive of dental fear regardless of age of onset. A family history of dental anxiety was predictive of child onset only. Adolescent-onset subjects were characterized by trait anxiety and adult-onset subjects by multiple severe fears and symptoms indicative of psychiatric problems. The three groups were similar in terms of their physiological, cognitive, and behavioral responses to dental treatment. However, adolescent- and adult-onset subjects were more hostile toward and less trusting of dentists. These results indicate that child-onset subjects were more likely to fall into the exogenous etiological category suggested by Weiner and Sheehan (1990), while adult-onset subjects were more likely to fall into the endogenous category.

Diagnostic categories of dental anxiety: a population-based study.

This study aimed to use a population-based sample to assess the psychological validity of the Seattle system for diagnosing dentally anxious individuals. This system consists of four diagnostic types in which such individuals are categorized according to the main source of their fear regarding dental treatment. Subjects were 1420 randomly selected adults aged 18 years and over who took part in a two-stage mail survey. The questionnaires contained measures of dental anxiety and standardized measures of general anxiety and fearfulness. Allocation to the Seattle categories was based on responses to four diagnostic items. Overall, 16.4% of the sample were dentally anxious. Their distribution across the four Seattle types was as follows: type I (simple conditioned phobia)--49.6%; type II (fear of catastrophe)--7.8%; type III (generalized anxiety)--19.4% and type IV (distrust of dentists)--9.9%. The remaining 13.3% could not be categorized. Judging by their scores on measures of dental anxiety, these subjects were borderline cases. Scores on the measures of anxiety and fearfulness indicated that the diagnostic system was valid and identified sub-groups of the dentally anxious population which were internally consistent. However, all subjects indicated extreme fear of dental treatment and were broadly similar in terms of their cognitive and behavioral responses to dental care. Of particular interest was the distribution of diagnoses according to age. Younger subjects were more likely to be categorized as type I, while older subjects were more likely to be categorized as type III. Overall, the results indicate that dental anxiety is a complex fear with a number of components.

Characteristics of early unpleasant dental experiences.

There is evidence in the literature that dentally anxious individuals are not a homogeneous group. Various ways of categorizing them have been suggested. These categories have stemmed primarily from clinical experience or psychiatric diagnoses. In addition, Reiss' (1987, 1991) expectancy theory of fear, anxiety and panic appears to fit some of the etiological data. At the simplest level, it is suggested that dental anxiety may result from direct conditioning experiences or from a constitutional vulnerability to develop anxiety-based problems. Taking conditioning theory and Reiss's model as a basis, it was predicted dental events deemed unpleasant would fall under four categories: (a) events relating to dental specific procedures and stimuli, (b) events relating to injuries, (c) events relating to emotional responses and (d) events relating to dental personnel behavior. In addition, it was predicted that individuals who would report high-anxiety sensitivity as measured by the anxiety sensitivity index (ASI) would be more likely to perceive unpleasant incidents relating to injuries, emotional responses and dental personnel behavior than individuals with low-anxiety sensitivity. On the other hand, everyone would be affected by incidents relating to specific dental procedures and stimuli. The participants were 510 university students who were surveyed during class time. The first prediction was supported but the second one was only partially supported, in that, participants who obtained high scores on the ASI differed from the others only regarding injuries.

Determinants of positive and negative attitudes toward dentistry.

Previous studies have primarily investigated the determinants of negative attitudes toward dentistry. Little is known about the reasons for positive attitudes. Using a group of university students who were surveyed during 1996, this study therefore examined both positive and negative attitudes to dentistry. It was initially predicted that dentally anxious individuals would be more likely to have negative feelings about dentistry than non-dentally anxious individuals, and would attribute this attitude to specific experiences. The study found that the majority of participating students had a positive attitude toward dentistry, and that participants with low levels of dental anxiety were more likely to have a positive attitude than those with a high level of anxiety. However, highly dentally anxious individuals were just as likely to feel positive toward dentistry as they were to feel negative. A substantial proportion of students claimed to have had painful or distressing experiences at the dentist during their adolescence. However, experiencing a painful or distressing incident was not related to having a negative attitude. The majority of the students who felt negative toward dentistry attributed this attitude to an unspecific experience, although dentally anxious individuals were likely to be more specific than non-dentally anxious individuals. Women participants appeared to have experienced painful or distressing incidents at a younger age than the men. The authors concluded that the factors involved in the development and maintenance of an individual's attitude toward dentistry are complex, and that dentists should be concerned with the promotion of positive attitudes rather than attempting to resolve negative ones.

Gender and age differences in attitudes to dental pain and dental control.

In the literature, it is usual to find women and younger subjects reporting higher levels of dental anxiety than men and older subjects. Fear of pain was found to be the most important predictor of dental anxiety and issues of control were also related to such anxiety. Therefore, it was predicted that gender and age differences would be reflected in attitudes to pain and control. Subjects were randomly selected from the voters' list in metropolitan Toronto and mailed a questionnaire with a request for cooperation in a study of their thoughts, feelings, and behaviour regarding dental treatment. The questionnaire included demographic data, measures of dental anxiety and painful experiences as well as the Pain Anxiety Symptoms Scale and the Iowa Dental Control Index. The results supported the main predictions. In addition, attitudes to pain and control were found to be complex phenomena with characteristic gender differences.

Overlap between dental anxiety and blood-injury fears: psychological characteristics and response to dental treatment.

The relationship between dental anxiety and blood/body injury (BI) fears was examined in a sample of 1420 adults. Based on their responses to two mail questionnaires, they were classified into one of four groups: Group 1--neither dentally anxious nor BI fearful; Group 2--BI fearful only; Group 3--dentally anxious only; Group 4--both dentally anxious and BI fearful. Overall, only 16% of dentally anxious subjects were BI fearful while 31.6% of those with high levels of BI fears were dentally anxious. While subjects in Group 2 were more fearful of dentistry than those in Group 1, they were substantially less so than subjects in Groups 3 and 4. Moreover, even BI stimuli in the dental setting evoked lower levels of anxiety for subjects in Group 2 compared to Group 3 and 4. However, rates of fainting or near fainting experiences in the dental situation were similar for all three groups. Group 3 and 4 were similar in terms of fear evoking stimuli and patterns of anxiety response. Subjects in Group 4 had more agoraphobic symptoms and social interaction fears and had higher scores on the Anxiety Sensitivity Index and Speilberger Trait Anxiety Index. This suggests that Group 4 is comprised of individuals who are more likely to be multiphobic and exhibit generalized anxiety states. Although BI fears are a significant component of dental anxiety, their overall contribution is relatively small.

Who is dentally anxious? Concordance between measures of dental anxiety.

Studies of the prevalence of dental anxiety in general population samples have produced estimates which range from a low of 2.6% to a high of 20.4%. It is not clear whether these reflect real differences among populations or whether they are the result of the use of different measures and different cut-off points. We undertook a large scale mail survey of dental anxiety in a random sample of the adult population living in Metropolitan Toronto designed to assess the performance of and agreement between three measures. These were Corah's DAS, the single item used by Milgrom and colleagues in Seattle and the ten-point fear scale used by Gatchel. These measures and their published cut-off points produced prevalence estimates of 10.9%, 23.4% and 8.2% respectively. While there was a significant association between scores on pairs of measures the agreement between them was far from perfect. Kappa values ranged from 0.37 to 0.56, indicating only fair to moderate agreement beyond chance. There was evidence to indicate that the dentally anxious subjects identified by each measure differed according to certain behavioural and other characteristics. The results of the study suggest the need to revisit the issue of measurement in studies of dental anxiety.

Negative dental experiences and their relationship to dental anxiety.

Although negative dental experiences are often cited as the major factor in the development of dental anxiety, very few studies have provided data on their prevalence. The studies that are available used limited samples from which it is not possible to generalise, or confined their enquiries to painful experiences only. In this paper data are provided on negative dental experiences and their relationship to dental anxiety obtained from a large, random sample of the general population. Just over three-quarters reported what are termed as direct negative experiences; 71 per cent had had experiences that were painful, 23 per cent experiences that were frightening and 9 per cent experiences that were embarrassing. Such experiences were not confined to childhood. For 23 per cent, the first experience of this kind happened during adolescence and for 40 per cent in adulthood. The relationship between these experiences and dental anxiety was strong. Subjects reporting all three types of experience were 22.4 times at risk of being dentally anxious than subjects reporting none of them. The data suggested that the nature of these unpleasant experiences was more important than the age at which they occurred in predicting dental anxiety. One third of dentally anxious subjects reported a negative response experience in the form of feeling faint, fainting or having a panic attack while at the dentist. Further research using more appropriate methods is needed to clarify the role of dental experiences in the genesis of dental anxiety.

Disproportionate dental anxiety in the over 50s.

Explanations of dental anxiety in terms of either conditioning or personality predispositions alone are not sufficient to account for all individuals presenting with dental anxiety, since they are not a homogenous group. It was hypothesized that individuals, with wide ranging anxiety problems would be more likely to carry dental anxiety into old age. This prediction was supported by a comparison of older dentally anxious individuals with other older individuals who admitted to dental anxiety previously but were no longer dentally anxious. The results were interpreted in terms of Lang's bioinformation model of anxiety.

The 42.5 kDa subunit of the NADH: ubiquinone oxidoreductase (complex I) in higher plants is encoded by the mitochondrial nad7 gene.

The N-terminal amino acid sequence of a 42.5 kDa subunit of the NADH: ubiquinone oxidoreductase (complex I) from potato has been determined by direct protein sequencing. The sequence was found to be homologous to that of the nuclear-encoded 49 kDa complex I subunit of bovine and Neurospora mitochondria and to the sequence deduced from the mitochondrial nad7 gene identified in the mitochondrial (mt) DNA of tryp anosomes and the moss Marchantia. An oligonucleotide probe derived from the potato N-terminal protein sequence hybridized only to the plant mtDNA. Immunoprecipitation of in-organello 35S-labelled potato and wheat mitochondrial translation products with an antibody directed against the Neurospora 49 kDa complex I subunit indicates that at least in these plants the NAD7 protein is synthesized within the organelle. Comparisons of genomic, cDNA and protein sequences of the 5' coding region reveal three codons that are changed by RNA-editing and confirm translation of the edited transcripts in plant mitochondria. The NAD7 protein appears to undergo post-translational processing since the N-terminal methionine residue is absent from the mature mitochondrial protein.

Long-term follow-up of treated dental phobics.

Behavioural treatment programmes have been shown repeatedly to be effective in alleviating dental anxiety but few studies have provided long-term follow-ups. In this study, dentally anxious Ss who had completed a 4-session behavioural group programme were followed up for periods between 1 and 4 years after successful completion of treatment. It was hypothesized that dental visit satisfaction would be associated with regular dental attendance. 88% of Ss contacted agreed to cooperate; of these, 70% were still maintaining regular check-ups. There were no differences between regular and irregular attenders in terms of age, gender, education, marital status, degree of pre-treatment avoidance or time elapsed since completion of the programme. However, Ss who did not see their dentists regularly were more likely to have shown higher levels of anxiety immediately after completing the programme, less concordance between the subjective and overt behavioural aspects of anxiety and to have experienced more invasive than non-invasive procedures than the others. It was argued that dentally anxious individuals are not a homogeneous group and that a better understanding of their individual differences would lead to the development of more efficacious treatment procedures.

Purification of the NADH:ubiquinone oxidoreductase (complex I) of the respiratory chain from the inner mitochondrial membrane of Solanum tuberosum.

The plant NADH:ubiquinone oxidoreductase (or complex I) was isolated from potato (Solanum tuberosum) mitochondria. The multisubunit enzyme was solubilized with detergents, Triton X-100 and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), out of the inner mitochondrial membranes and purified by hydroxylapatite and gel filtration chromatography. The preparation was found to be virtually free of any ATPase or transhydrogenase contamination. Complex I of potato is composed of at least 32 individual subunits as detected in silver-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis and has a total molecular mass of about 900 kDa. The enzyme preparation showed an NADH:ubiquinone-2 reductase activity of 11.5 mumol x min-1 x mg-1 and is strongly inhibited by rotenone. Heterologous polyclonal antibodies against the 70- and 49-kDa subunits of the Neurospora crassa complex I and against the wheat NAD9 subunit cross-reacted specifically with the respective potato subunits. Four of the 10 NH2-terminal sequences determined show significant similarities to Neurospora or bovine complex I subunits and allow a tentative assignment of these subunits.