Is self-rated health comparable across cultures and genders?

Self-rated health is a frequently used health indicator, but there is little data on its comparability across cultures. We employed samples from Tampere, Finland, and Florence, Italy, of the European Longitudinal Study on Aging to examine the cultural and gender differences in self-rated health. Personal interview data was used and vital status ascertained after 7 years. After adjusting for several health-related variables, we found no substantial difference in self-rated health between genders, although women in Florence were three times and men in Florence four times more likely to report good self-rated health than men in Tampere. The correlational structure of self-rated health was similar in both areas. The significant graded association between self-rated health and mortality in both areas was mostly explained by other health indicators included in a multivariate model. Results suggest that self-rated health is a useful summary of physical health, but it may predict mortality better in men than in women and be sensitive to cultural environment. Therefore, direct gender and cultural comparisons of self-rated health should be made with caution.

Predator avoidance and immune defence: costs and trade-offs in snails

Organisms are often confronted by both predators and pathogens. Defending against such widely divergent enemies requires more than one type of defence. Multiple defences, however, raise the possibility of trade-offs among defences. We tested for such trade-offs by manipulating the level of predator-avoidance behaviour and immune function in the freshwater snail Lymnaea stagnalis (Gastropoda: Pulmonata). Our results show that predator avoidance and immune function had clear costs in terms of reproduction and survival. Further, we show that increased levels of predator-avoidance behaviour reduced the snails' ability to defend against potential pathogens. Predator-avoidance behaviour may thus have the additional indirect cost of reduced immunocompetence and increased susceptibility to pathogens. Our results suggest that ecological factors (e.g. predator density) may considerably modify the expression and costs of immune defences.

A standardized plaque reduction assay for determination of drug susceptibilities of cytomegalovirus clinical isolates

Twelve laboratories collaborated in formulating and testing a standardized plaque reduction assay for cytomegalovirus (CMV) cell-associated clinical isolates. Four characterized and plaque-purified CMV strains, as well as six coded clinical isolates obtained after antiviral therapy, were distributed and tested. Good agreement was obtained for four of the clinical isolates, but a broad distribution of results was obtained for two isolates. Analysis of these results indicates the problems associated with clinical isolates, including the large genetic variability and the highly cell-associated phenotype. This collaborative effort, by addressing these problems, represents a significant step toward the development of a standardized assay.

Effects of host condition on susceptibility to infection, parasite developmental rate, and parasite transmission in a snail-trematode interaction

Whether or not organisms become infected by parasites is likely to be a complex interplay between host and parasite genotypes, as well as the physiological condition of both species. Details of this interplay are very important because physiology-driven susceptibility has the potential to confound genetic coevolutionary responses. Here we concentrate on how physiological aspects of infection may interfere with genetic-based infectivity in a snail-trematode (Potamopyrgus antipodarum/Microphallus sp.) interaction by asking: (1) how does host condition affect susceptibility to infection? and (2) how does host condition affect the survival of infected individuals? We manipulated host condition by experimentally varying resources. Contrary to our expectation, host condition did not affect susceptibility to infection, suggesting that genetics are more important than physiology in this regard. However, hosts in poor condition had higher parasite-induced mortality than hosts in good condition. Taken together, these results suggest that coevolutionary interactions with parasites may depend on host condition, not by altering susceptibility, but rather by affecting the likelihood of parasite transmission.

Postural balance and self-reported functional ability in 75-year-old men and women: a cross-national comparative study

OBJECTIVE

To study postural balance in relation to self-reported functional ability (mobility and ADL) and general physical activity in elderly men and women living in three different Nordic environments.

PARTICIPANTS

A random sample of 448 men and 556 women from among the 75-year-old residents in Glostrup, Denmark, and Göteborg, Sweden, and all the residents of relevant age (127 men and 261 women) in Jyväskylä, Finland.

MEASUREMENTS

Assessment of postural balance with eyes open and closed using a piezoelectric force platform. A structured interview on self-reported functional ability and physical activity. An in-laboratory medical examination.

RESULTS

In spite of some differences in balance between the groups studied (better results in women compared with men and, to some extent, better results in the participants from Denmark and Finland than in those from Sweden), the performance in the balance tests was similarly associated with functional ability within all groups. The subjects reporting no need of help in performing the ADL and mobility functions performed significantly better in the balance tests. These differences were seen more clearly in the control of anteroposterior movement of center of forces than in the mediolateral direction. The performance in the balance tests was also significantly better among the subjects reporting a higher level of general physical activity than in their less active counterparts. Physical activity and than in their less active counterparts. Physical activity and certain long standing illnesses modified significantly the relationship between postural balance and ADL-performance. When these factors were analyzed simultaneously, the role of balance as a predictor of ADL-performance largely disappeared.

CONCLUSIONS

The results suggest that good balance is one of the prerequisites of performance without difficulty in mobility and ADL functions. Physical exercise may help to maintain balancing abilities in old age; good balance, in turn, may also enable a physically active way of life. The associations of balance with functional ability and physical activity were independent of sex and locality. The results also support the validity of static stabilometry as a tool for evaluating threats to functional limitations in older subjects.

Reaction and movement times in men of different ages: a population study

Tests of psychomotor and motor speed at different levels of complexity were studied in random samples of men aged 31 to 35, 51 to 55, and 71 to 75 yr. The study was performed as a part of a larger research project on health and functional aging. Analyses indicated significantly slower responses among older men at all levels of test complexity (maximal knee extension velocity, tapping rate, simple and choice reaction and movement times). There were marked differences both between the youngest and the middle-aged groups and between the middle-aged and the oldest groups. Within the age groups high psychomotor and motor speed were associated with a favourable functioning of certain senses (vibration sensitivity and postural balance), with a high isometric muscular force, and with a high directly assessed aerobic capacity. The most important covariants of the speed functions within the age groups were, however, cognitive performance, length of education, and perceived health.

Administration of Bifidobacterium animalis subsp. lactis BB-12 in early childhood: a post-trial effect on caries occurrence at four years of age

Probiotic bifidobacteria are widely used in the prevention of childhood diseases. These bacteria are also associated with caries occurrence. The present secondary analysis in a low-caries population evaluated the effect of early administration of Bifidobacterium animalis subsp. lactis BB-12 (BB-12) on caries occurrence and identified markers of dental decay in early childhood. In the original randomized, double-blind, placebo-controlled study (NCT00638677, http://www.clinicaltrials.gov), infants (n = 106) received BB-12, xylitol or sorbitol tablets from the age of 1-2 months to 2 years with a slow-release pacifier or a spoon (daily dose of BB-12 10(10) colony-forming units, polyol 200-600 mg). The present data were collected using clinical examinations and questionnaires at the age of 4 years. The occurrence of dental caries was assessed using the International Caries Detection and Assessment System. Oral hygiene status and mutans streptococci (MS) levels were also determined. No differences were detected between the study groups in the occurrence of enamel caries (p = 0.268) or obvious dentinal caries (p = 0.201). The occurrence of caries was associated with daily consumption of sweet drinks (p = 0.028), visible plaque observed (p = 0.002) and MS detected in the dental plaque (p = 0.002). Administration of BB-12 in infancy does not seem to increase or decrease the occurrence of caries by 4 years of age in a low-caries population.

Bifidobacterium animalis subsp. lactis BB-12 administration in early childhood: a randomized clinical trial of effects on oral colonization by mutans streptococci and the probiotic

A randomized clinical trial studied the effects of early administration of Bifidobacterium animalis subsp. lactis BB-12 (BB-12) on oral colonization of (1) mutans streptococci (MS), and (2) BB-12. In this double-blind, placebo-controlled study, infants (n = 106) received probiotic bacteria (BB-12 group), xylitol (X group), or sorbitol (S group). Test tablets were administered twice a day (from the age of 1-2 months) with a novel slow-release pacifier or a spoon (daily dose of BB-12 10(10) CFU, polyol 200-600 mg). Samples were collected from mucosa/teeth at the age of 8 months and 2 years for BB- 12 determination (qPCR) and plate culturing of MS (MSB, TYCSB), lactobacilli (Rogosa) and yeasts (Sabouraud). The MS levels of the mothers were determined (Dentocult SM Strip Mutans). The baseline characteristics of the three groups were similar. Mean duration of tablet delivery was 14.9 ± 6.7 months. In all groups, >90% of the mothers showed high MS counts (log CFU ≥5). MS colonization percentages of the children at the age of 2 years were rather low (BB-12 group: 6%; X group: 31%; S group: 10%; p < 0.05). The levels of lactobacilli and yeasts did not differ between the groups. BB-12 cell counts barely exceeding the detection limit were found in three of the oral samples of the 8-month-old children; however, the 2-year samples did not contain BB-12. The early administration of BB-12 did not result in permanent oral colonization of this probiotic or significantly affect MS colonization in the children.

Correlates of vibrotactile thresholds in men of different ages

As a part of a larger gerontological research project vibrotactile thresholds on the inner malleolus of the ankle were studied in 355 men aged 31-35, 51-55 and 71-75 years. The groups studied were random samples of men living in the town of Jyväskylä in Finland in the year 1981. The thresholds were assessed at three frequencies: 50 Hz, 100 Hz and 250 Hz. The thresholds were associated with age at all frequencies, the means of the threshold values being significantly higher in the older age groups. Within the age groups the thresholds correlated positively with height. In addition, reaction and movement time, leg extension velocity, and postural sway were associated with the thresholds. Neither general health status nor occupational or educational background, or living habits had significant influence on the thresholds within the age groups. The results suggest that the elevation of vibrotactile thresholds is an inherent manifestation of aging in the nervous system. In addition to age, the height of the respondents is among the factors that should be taken into account when interindividual comparisons are made, if the measurement is on distal parts of the body.

Direct and correlative phenotypic selection on life-history traits in three pre-industrial human populations

Because natural selection acts simultaneously on several correlated traits, can be under both direct and correlative selection simultaneously. Correlative selection may either weaken or magnify the association between a trait and fitness. Direct effect of a single trait on fitness can be assessed by removing the effects of correlative selection with multivariate techniques. We studied the phenotypic selection on demographic life-history traits in three pre-industrial human populations, which experienced different mortality environments. We used path-analysis to estimate direct and correlative selection on different traits in females and males. Our results indicate substantial differences among the sexes in the force of phenotypic selection on key life-history traits. For females, the most important component of reproductive success was the age at first reproduction. Most important component of fitness for males was the quality of mate. In addition, our analysis revealed considerable among-population variation in the selection on life-history traits. These differences are in accord with the historical notes of among-population variation in the lifestyle and harshness of the environment, suggesting that among-population variation in life-history traits may have been a response to the environmental variation.

Thrombotic thrombocytopenic purpura in a human immunodeficiency virus (HIV)-seropositive homosexual man

A case of thrombotic thrombocytopenic purpura (TTP) in a human immunodeficiency virus (HIV)-seropositive homosexual man is reported. The patient improved after corticosteroid and plasma exchange therapy was instituted. The case demonstrated most of the classic features of TTP, including histologic evidence of fibrin thrombi in small blood vessels. Atypical features included reduced number of megakaryocytes in the bone marrow and only partial resolution of thrombocytopenia after therapy was begun. An autoimmune thrombocytopenia has been well-characterized in HIV-antibody-seropositive homosexual men. Physicians caring for HIV-seropositive persons should also be aware of a possible association with TTP.

Natural selection on age-specific fertilities in human females: comparison of individual-level fitness measures

Lifetime reproductive success and timing of reproduction are key components of life-history evolution. To understand the evolution of reproductive schedules, it is important to use a measure of fitness that is sensitive both to reproductive quantity and reproductive timing. There is a contradiction between the theory, which mainly focuses on the rate measures of fitness (r and lambda), and empirical studies, which mainly use lifetime reproductive success (LRS), or some of its correlates, as a fitness measure. We measured phenotypic selection on age-specific fertilities in three pre-modern human populations using individually estimated finite rate of increase, er (lambda). We found that lambda and lifetime reproductive success ranked individuals differently according to their fitness: for example, a female giving birth to four children at a young age may actually have a higher fitness than a female giving birth to six children at a greater age. Increase in fertility at the young age classes (15-19 years) was favoured by selection, but the intensity of selection on fertility was higher in the older age classes (20-30 years), where the variance in fertility was highest. Hence, variation in fertility in the older age classes (20-30) was actually responsible for most of the observed variation in fitness among the individuals. Additionally, more than 90% of variation in fitness (lambda) was attributable to individual differences in LRS, whereas only about 5% of all variation in fitness was due to differences in the reproductive schedule. The rate-sensitive fitness measure did not significantly challenge the importance of total fertility as a component of fitness in humans. However, the rate-sensitive measure clearly allowed more accurate estimation of individual fitness, which may be important for answering some more specific questions.

Distinct roles of carbohydrate esterase family CE16 acetyl esterases and polymer-acting acetyl xylan esterases in xylan deacetylation

Mass spectrometric analysis was used to compare the roles of two acetyl esterases (AE, carbohydrate esterase family CE16) and three acetyl xylan esterases (AXE, families CE1 and CE5) in deacetylation of natural substrates, neutral (linear) and 4-O-methyl glucuronic acid (MeGlcA) substituted xylooligosaccharides (XOS). AEs were similarly restricted in their action and apparently removed in most cases only one acetyl group from the non-reducing end of XOS, acting as exo-deacetylases. In contrast, AXEs completely deacetylated longer neutral XOS but had difficulties with the shorter ones. Complete deacetylation of neutral XOS was obtained after the combined action of AEs and AXEs. MeGlcA substituents partially restricted the action of both types of esterases and the remaining acidic XOS were mainly substituted with one MeGlcA and one acetyl group, supposedly on the same xylopyranosyl residue. These resisting structures were degraded to great extent only after inclusion of α-glucuronidase, which acted with the esterases in a synergistic manner. When used together with xylan backbone degrading endoxylanase and β-xylosidase, both AE and AXE enhanced the hydrolysis of complex XOS equally.

Spatial variation in susceptibility to infection in a snail-trematode interaction

Parasites should be better at infecting hosts from sympatric populations than allopatric populations most of the time (parasite local adaptation). In a previous study of a population of snail parasites (Microphallus sp.) from Lake Alexandrina, New Zealand, we found that Microphallus was more infective to snails (Potamopyrgus antipodarum) in shallow water but not in deep water. Here, we repeated the original study and also monitored the development of the parasite. We found that parasites from shallow water were more infective to hosts from shallow water and developed more rapidly in these hosts. In contrast, parasites from deep water were not more infective to hosts from deep water and did not develop more rapidly in them. These results suggest clinal variation in the susceptibility of these snails, with shallow-water snails more susceptible than deep-water snails. We offer 2 possible explanations for these results. First, gene flow in the Microphallus population is primarily from shallow to deep water, leading to an asymmetric pattern of local adaptation. Alternatively, snails from shallow water may be more susceptible for reasons independent of gene flow, perhaps due to differences in host condition between habitats.

Are cryptic host species also cryptic to parasites? Host specificity and geographical distribution of acanthocephalan parasites infecting freshwater Gammarus

Many parasites infect multiple host species. In coevolving host-parasite interactions, theory predicts that parasites should be adapted to locally common hosts, which could lead to regional shifts in host preferences. We studied the interaction between freshwater Gammarus (Crustacea, Amphipoda) and their acanthocephalan parasites using a large-scale field survey and experiments, combined with molecular identification of cryptic host and parasite species. Gammarus pulex is a common host for multiple species of Acanthocephala in Europe but, in Switzerland, is less common than two cryptic members of the Gammarus fossarum species complex (type A and type B). We found that natural populations of these cryptic species were frequently infected by Pomphorhynchus tereticollis and Polymorphus minutus. Four additional parasite species occurred only locally. Parasites were more common in G. fossarum type B than in type A. Infection experiments using several host and parasite sources confirmed consistently lower infection rates in G. pulex than in G. fossarum type A, suggesting a general difference in susceptibility between the two species. In conclusion, we could show that cryptic host species differ in their interactions with parasites, but that these differences were much less dramatic than differences between G. fossarum (type A) and G. pulex. Our data suggest that the acanthocephalans in Switzerland have adapted to the two most common Gammarus species in this region where host species frequencies differ from near-by regions in Europe.

Pure-tone thresholds, speech understanding, and their correlates in samples of men of different ages

Pure-tone thresholds and speech understanding were studied in three samples of men of different ages (31-35, 51-55 and 71-75 years). The air-conducted pure-tone thresholds were measured at 125-8,000 Hz and speech understanding by the help of interrupted and masked speech tests. The audiological measures were related to measures of other sensory functions, psychomotor speed, cognitive functions, psychic well-being, occupational and educational background and health. The results indicated a clear decrement in all audiological measures when proceeding from younger to older age groups. The results of the speech-understanding tests correlated significantly with the pure-tone thresholds both at 4,000 Hz and at the mean of three frequencies (500, 1,000, 2,000 Hz) in the speech area. The audiological measures were not associated with other sensory functions or psychic well-being but showed significant correlations with psychomotor speed and cognitive functions. The most important predictors of the auditory functions within the age groups were occupational status, noise exposure at work, cognitive capacity, education, and number of disease symptoms, which, in addition, correlated with each other.

Dental services utilization between 1977 and 1995 by Finnish adolescents of different socioeconomic levels

Equal distribution of health care services has long been a major goal of health policy in the Nordic countries. According to these guidelines, every child is expected to have an examination and treatment at least every second year. The aim of this study was to analyze the trends and, in particular, the socioeconomic differences in dental visits between 1977 and 1995. The data were collected as part of a nationwide research program, the Adolescent Health and Lifestyle Survey, which began in 1977. Every second year a self-administered questionnaire was mailed to a representative sample of 14-, 16- and 18-year-old Finns. The sample sizes in the surveys varied from 2422 to 9556, making a total of 56,605 subjects in the whole study. The response rates in different years varied from 77% to 88%. The percentage of adolescents visiting a dentist increased between 1977 and 1981 and thereafter remained stable. Dental visits seemed to correlate with the occupational and educational status of the parents up to 1983, but not after that. The Finnish primary oral health care policy seems to have gained a major objective by eliminating social inequality in dental service utilization among adolescents.

Ecological divergence of closely related Diplostomum (Trematoda) parasites

Parasite life-cycles present intriguing model systems to study divergence in resource use and ecology between parasite taxa. In ecologically similar taxa, consistent selective forces may lead to convergence of life-history traits, but resource overlap and similarity of life-cycles may also promote divergence between the taxa in (1) use of host species or (2) specific niche within a host. We studied the life-history characteristics of 2 sympatric species of Diplostomum parasites, D. spathaceum and D. gasterostei, concentrating particularly on differences in intermediate host use and characteristics of the infective stages between the species. This group of trematodes is a notoriously difficult challenge for morphological taxonomy and therefore any information on the ecology of these species can also be helpful in resolving their taxonomy. We observed that these species indeed had diverged as they used mainly different snail and fish species as intermediate hosts and in controlled experiments infected different regions of the eye (lens and vitreous body) of a novel fish host. Interestingly, cercarial characteristics (activity and life-span) were similar between the species and the species were difficult to separate at the cercarial stage unless one observes their swimming behaviour. The release of cercaria from the snail hosts was higher in D. spathaceum, but when cercarial numbers were proportioned to the volume of the snail host, the production was higher in D. gasterostei suggesting differences in the rate of snail host exploitation between the parasite species. These results corroborate the prediction that closely related parasite taxa which are competing for the same resources should have diverged in their life-history characteristics and host use.

Clonal diversity driven by parasitism in a freshwater snail

One explanation for the widespread abundance of sexual reproduction is the advantage that genetically diverse sexual lineages have under strong pressure from virulent coevolving parasites. Such parasites are believed to track common asexual host genotypes, resulting in negative frequency-dependent selection that counterbalances the population growth-rate advantage of asexuals in comparison with sexuals. In the face of genetically diverse asexual lineages, this advantage of sexual reproduction might be eroded, and instead sexual populations would be replaced by diverse assemblages of clonal lineages. We investigated whether parasite-mediated selection promotes clonal diversity in 22 natural populations of the freshwater snail Melanoides tuberculata. We found that infection prevalence explains the observed variation in the clonal diversity of M. tuberculata populations, whereas no such relationship was found between infection prevalence and male frequency. Clonal diversity and male frequency were independent of snail population density. Incorporating ecological factors such as presence/absence of fish, habitat geography and habitat type did not improve the predictive power of regression models. Approximately 11% of the clonal snail genotypes were shared among 2-4 populations, creating a web of 17 interconnected populations. Taken together, our study suggests that parasite-mediated selection coupled with host dispersal ecology promotes clonal diversity. This, in return, may erode the advantage of sexual reproduction in M. tuberculata populations.

Pathologic findings and toxin identification in cyanobacterial (Nodularia spumigena) intoxication in a dog

A 3-year-old Cairn Terrier dog that had been in contact with sea water containing cyanobacteria (blue-green algae) was euthanized because of acute hepatic failure and anuria after a 5-day illness. Histologic findings included lytic and hemorrhagic centrilobular hepatocellular necrosis and renal tubular necrosis. The cyanotoxin nodularin was detected in liver and kidney by high-performance liquid chromatography-mass spectrometry. Nodularin is a potent hepatotoxin produced by the algal species Nodularia spumigena. The intensity of algal blooms has increased during the past decades in the Baltic Sea region, thus increasing the risk for intoxications in domestic and wild animals. The authors describe the pathologic findings of cyanobacterial toxicosis in a dog with direct identification of the toxin from organ samples.