A Placebo-controlled double-blinded test of the biodiversity hypothesis of immune-mediated diseases: Environmental microbial diversity elicits changes in cytokines and increase in T regulatory cells in young children

BACKGROUND

According to the biodiversity hypothesis of immune-mediated diseases, lack of microbiological diversity in the everyday living environment is a core reason for dysregulation of immune tolerance and - eventually - the epidemic of immune-mediated diseases in western urban populations. Despite years of intense research, the hypothesis was never tested in a double-blinded and placebo-controlled intervention trial.

OBJECTIVE

We aimed to perform the first placebo-controlled double-blinded test that investigates the effect of biodiversity on immune tolerance.

METHODS

In the intervention group, children aged 3-5 years were exposed to playground sand enriched with microbially diverse soil, or in the placebo group, visually similar, but microbially poor sand colored with peat (13 participants per treatment group). Children played twice a day for 20 min in the sandbox for 14 days. Sand, skin and gut bacterial, and blood samples were taken at baseline and after 14 days. Bacterial changes were followed for 28 days. Sand, skin and gut metagenome was determined by high throughput sequencing of bacterial 16 S rRNA gene. Cytokines were measured from plasma and the frequency of blood regulatory T cells was defined as a percentage of total CD3 +CD4 + T cells.

RESULTS

Bacterial richness (P < 0.001) and diversity (P < 0.05) were higher in the intervention than placebo sand. Skin bacterial community, including Gammaproteobacteria, shifted only in the intervention treatment to resemble the bacterial community in the enriched sand (P < 0.01). Mean change in plasma interleukin-10 (IL-10) concentration and IL-10 to IL-17A ratio supported immunoregulation in the intervention treatment compared to the placebo treatment (P = 0.02). IL-10 levels (P = 0.001) and IL-10 to IL-17A ratio (P = 0.02) were associated with Gammaproteobacterial community on the skin. The change in T_reg frequencies was associated with the relative abundance of skin Thermoactinomycetaceae 1 (P = 0.002) and unclassified Alphaproteobacteria (P < 0.001). After 28 days, skin bacterial community still differed in the intervention treatment compared to baseline (P < 0.02).

CONCLUSIONS

This is the first double-blinded placebo-controlled study to show that daily exposure to microbial biodiversity is associated with immune modulation in humans. The findings support the biodiversity hypothesis of immune-mediated diseases. We conclude that environmental microbiota may contribute to child health, and that adding microbiological diversity to everyday living environment may support immunoregulation.

Long-term biodiversity intervention shapes health-associated commensal microbiota among urban day-care children

BACKGROUND

In modern urban environments children have a high incidence of inflammatory disorders, including allergies, asthma, and type1 diabetes. The underlying cause of these disorders, according to the biodiversity hypothesis, is an imbalance in immune regulation caused by a weak interaction with environmental microbes. In this 2-year study, we analyzed bacterial community shifts in the soil surface in day-care centers and commensal bacteria inhabiting the mouth, skin, and gut of children. We compared two different day-care environments: standard urban day-care centers and intervention day-care centers. Yards in the latter were amended with biodiverse forest floor vegetation and sod at the beginning of the study.

RESULTS

Intervention caused a long-standing increase in the relative abundance of nonpathogenic environmental mycobacteria in the surface soils. Treatment-specific shifts became evident in the community composition of Gammaproteobacteria, Negativicutes, and Bacilli, which jointly accounted for almost 40 and 50% of the taxa on the intervention day-care children's skin and in saliva, respectively. In the year-one skin swabs, richness of Alpha-, Beta-, and Gammaproteobacteria was higher, and the relative abundance of potentially pathogenic bacteria, including Haemophilus parainfluenzae, Streptococcus sp., and Veillonella sp., was lower among children in intervention day-care centers compared with children in standard day-care centers. In the gut, the relative abundance of Clostridium sensu stricto decreased, particularly among the intervention children.

CONCLUSIONS

This study shows that a 2-year biodiversity intervention shapes human commensal microbiota, including taxa that have been associated with immune regulation. Results indicate that intervention enriched commensal microbiota and suppressed the potentially pathogenic bacteria on the skin. We recommend future studies that expand intervention strategies to immune response and eventually the incidence of immune-mediated diseases.

Do Rural Second Homes Shape Commensal Microbiota of Urban Dwellers? A Pilot Study among Urban Elderly in Finland

According to the hygiene and biodiversity hypotheses, increased hygiene levels and reduced contact with biodiversity can partially explain the high prevalence of immune-mediated diseases in developed countries. A disturbed commensal microbiota, especially in the gut, has been linked to multiple immune-mediated diseases. Previous studies imply that gut microbiota composition is associated with the everyday living environment and can be modified by increasing direct physical exposure to biodiverse materials. In this pilot study, the effects of rural-second-home tourism were investigated on the gut microbiota for the first time. Rural-second-home tourism, a popular form of outdoor recreation in Northern Europe, North America, and Russia, has the potential to alter the human microbiota by increasing exposure to nature and environmental microbes. The hypotheses were that the use of rural second homes is associated with differences in the gut microbiota and that the microbiota related to health benefits are more diverse or common among the rural-second-home users. Based on 16S rRNA Illumina MiSeq sequencing of stool samples from 10 urban elderly having access and 15 lacking access to a rural second home, the first hypothesis was supported: the use of rural second homes was found to be associated with lower gut microbiota diversity and RIG-I-like receptor signaling pathway levels. The second hypothesis was not supported: health-related microbiota were not more diverse or common among the second-home users. The current study encourages further research on the possible health outcomes or causes of the observed microbiological differences. Activities and diet during second-home visits, standard of equipment, surrounding environment, and length of the visits are all postulated to play a role in determining the effects of rural-second-home tourism on the gut microbiota.

Associations between land cover categories, gaseous PAH levels in ambient air and endocrine signaling predicted from gut bacterial metagenome of the elderly

There is evidence that polycyclic aromatic hydrocarbons (PAHs) and human gut microbiota are associated with the modulation of endocrine signaling pathways. Independently, studies have found associations between air pollution, land cover and commensal microbiota. We are the first to estimate the interaction between land cover categories associated with air pollution or purification, PAH levels and endocrine signaling predicted from gut metagenome among urban and rural populations. The study participants were elderly people (65-79 years); 30 lived in rural and 32 in urban areas. Semi-Permeable Membrane devices were utilized to measure air PAH concentrations as they simulate the process of bioconcentration in the fatty tissues. Land cover categories were estimated using CORINE database and geographic information system. Functional orthologues for peroxisome proliferator-activated receptor (PPAR) pathway in endocrine system were analyzed from gut bacterial metagenome with Kyoto Encyclopaedia of Genes and Genomes. High coverage of broad-leaved and mixed forests around the homes were associated with decreased PAH levels in ambient air, while gut functional orthologues for PPAR pathway increased along with these forest types. The difference between urban and rural PAH concentrations was not notable. However, some rural measurements were higher than the urban average, which was due to the use of heavy equipment on active farms. The provision of air purification by forests might be an important determining factor in the context of endocrine disruption potential of PAHs. Particularly broad-leaved forests around homes may reduce PAH levels in ambient air and balance pollution-induced disturbances within commensal gut microbiota.

Biodiversity intervention enhances immune regulation and health-associated commensal microbiota among daycare children

As the incidence of immune-mediated diseases has increased rapidly in developed societies, there is an unmet need for novel prophylactic practices to fight against these maladies. This study is the first human intervention trial in which urban environmental biodiversity was manipulated to examine its effects on the commensal microbiome and immunoregulation in children. We analyzed changes in the skin and gut microbiota and blood immune markers of children during a 28-day biodiversity intervention. Children in standard urban and nature-oriented daycare centers were analyzed for comparison. The intervention diversified both the environmental and skin Gammaproteobacterial communities, which, in turn, were associated with increases in plasma TGF-β1 levels and the proportion of regulatory T cells. The plasma IL-10:IL-17A ratio increased among intervention children during the trial. Our findings suggest that biodiversity intervention enhances immunoregulatory pathways and provide an incentive for future prophylactic approaches to reduce the risk of immune-mediated diseases in urban societies.

Hexyl aminolevulinate, 5-aminolevulinic acid nanoemulsion and methyl aminolevulinate in photodynamic therapy of non-aggressive basal cell carcinomas: A non-sponsored, randomized, prospective and double-blinded trial

BACKGROUND

In the photodynamic therapy (PDT) of non-aggressive basal cell carcinomas (BCCs), 5-aminolevulinic acid nanoemulsion (BF-200ALA) has shown non-inferior efficacy when compared with methyl aminolevulinate (MAL), a widely used photosensitizer. Hexyl aminolevulinate (HAL) is an interesting alternative photosensitizer. To our knowledge, this is the first study using HAL-PDT in the treatment of BCCs.

OBJECTIVES

To compare the histological clearance, tolerability (pain and post-treatment reaction) and cosmetic outcome of MAL, BF-200 ALA and low-concentration HAL in the PDT of non-aggressive BCCs.

METHODS

Ninety-eight histologically verified non-aggressive BCCs met the inclusion criteria, and 54 patients with 95 lesions completed the study. The lesions were randomized to receive LED-PDT in two repeated treatments with MAL, BF-200 ALA or HAL. Efficacy was assessed both clinically and confirmed histologically at three months by blinded observers. Furthermore, cosmetic outcome, pain, post-treatment reactions fluorescence and photobleaching were evaluated.

RESULTS

According to intention-to-treat analyses, the histologically confirmed lesion clearance was 93.8% (95% confidence interval [CI] = 79.9-98.3) for MAL, 90.9% (95% CI = 76.4-96.9) for BF-200 ALA and 87.9% (95% CI = 72.7-95.2) for HAL, with no differences between the arms (P = 0.84). There were no differences between the arms as regards pain, post-treatment reactions or cosmetic outcome.

CONCLUSIONS

Photodynamic therapy with low-concentration HAL and BF-200 ALA has a similar efficacy, tolerability and cosmetic outcome compared to MAL. HAL is an interesting new option in dermatological PDT, since good efficacy is achieved with a low concentration.

Yard vegetation is associated with gut microbiota composition

Gut microbes play an essential role in the development and functioning of the human immune system. A disturbed gut microbiota composition is often associated with a number of health disorders including immune-mediated diseases. Differences in host characteristics such as ethnicity, living habit and diet have been used to explain differences in the gut microbiota composition in inter-continental comparison studies. As our previous studies imply that daily skin contact with organic gardening materials modify gut microflora, here we investigated the association between living environment and gut microbiota in a homogenous western population along an urban-rural gradient. We obtained stool samples from 48 native elderly Finns in province Häme in August and November 2015 and identified the bacterial phylotypes using 16S rRNA Illumina MiSeq sequencing. We assumed that yard vegetation and land cover classes surrounding homes explain the stool bacterial community in generalized linear mixed models. Diverse yard vegetation was associated with a reduced abundance of Clostridium sensu stricto and an increased abundance of Faecalibacterium and Prevotellaceae. The abundance of Bacteroides was positively and strongly associated with the built environment. Exclusion of animal owners did not alter the main associations. These results suggest that diverse vegetation around homes is associated with health-related changes in gut microbiota composition. Manipulation of the garden diversity, possibly jointly with urban planning, is a promising candidate for future intervention studies that aim to maintain gut homeostasis.

Correlates of different facets and components of beta diversity in stream organisms

Recently, community ecology has emphasized the multi-facetted aspects of biological diversity by linking species traits and the environment. Here, we explored environmental correlates of taxonomically-based and traits-based compositional distances using a comprehensive data set of diatom and macroinvertebrate communities. We also explored the responses of different beta diversity components (i.e., overall beta diversity, turnover, and nestedness) of beta diversity facets (i.e., taxonomically and traits-based beta diversity) to environmental distances. Partial Mantel tests were used to test the relationships between beta diversity and environmental distance (while controlling for spatial distances). Taxonomically-based beta diversity varied much more than traits-based beta diversity, indicating strong functional convergence. We found that taxonomically-based beta diversity was largely driven by the turnover component. However, the nestedness component contributed more to overall traits-based beta diversity than the turnover component. Taxonomically-based beta diversity was significantly correlated with environmental distances for both diatoms and macroinvertebrates. Thus, we found support for the role of environmental filtering as a driver of community dissimilarities of rather different biological groups. However, the strength of these relationships between beta diversity and environmental distances varied depending on the biological group, facet, component, and the way which the environmental variables were selected to calculate the explanatory (distance) matrix. Our results indicated that both taxonomically and traits-based approaches are still needed to better understand patterns and mechanisms affecting the organization of biological communities in streams. This is because different facets of biological communities may be driven by different mechanisms.

Temporal variation in indoor transfer of dirt-associated environmental bacteria in agricultural and urban areas

An agricultural environment and exposure to diverse environmental microbiota has been suggested to confer protection against immune-mediated disorders. As an agricultural environment may have a protective role, it is crucial to determine whether the limiting factors in the transfer of environmental microbiota indoors are the same in the agricultural and urban environments. We explored how sampling month, garden diversity and animal ownership affected the indoor-transfer of environmental microbial community. We collected litter from standardized doormats used for 2 weeks in June and August 2015 and February 2016 and identified bacterial phylotypes using 16S rRNA Illumina MiSeq sequencing. In February, the diversity and richness of the whole bacterial community and the relative abundance of environment-associated taxa were reduced, whereas human-associated taxa and genera containing opportunistic pathogens were enriched in the doormats. In summer, the relative abundances of several taxa associated previously with beneficial health effects were higher, particularly in agricultural areas. Surprisingly, the importance of vegetation on doormat microbiota was more observable in February, which may have resulted from snow cover that prevented contact with microbes in soil. Animal ownership increased the prevalence of genera Bacteroides and Acinetobacter in rural doormats. These findings underline the roles of season, living environment and lifestyle in the temporal variations in the environmental microbial community carried indoors. As reduced contact with diverse microbiota is a potential reason for immune system dysfunction, the results may have important implications in the etiology of immune-mediated, non-communicable diseases.

Ablative fractional laser-assisted photodynamic therapy for lentigo maligna: a prospective pilot study

BACKGROUND

Lentigo maligna (LM) is an in situ form of melanoma carrying a risk of progression to invasive lentigo maligna melanoma (LMM). LM poses a clinical challenge, with subclinical extension and high recurrence rates after incomplete surgery. Alternative treatment methods have been investigated with varying results. Photodynamic therapy (PDT) with methylaminolaevulinate (MAL) has already proved promising in this respect.

OBJECTIVES

To investigate the efficacy of ablative fractional laser (AFL)-assisted PDT with 5-aminolaevulinic acid nanoemulsion (BF-200 ALA) for treating LM.

METHODS

In this non-sponsored prospective pilot study, ten histologically verified LMs were treated with AFL-assisted PDT three times at 2-week intervals using a light dose of 90 J/cm² per treatment session. Local anaesthesia with ropivacaine was used. Four weeks after the last PDT treatment the lesions were treated surgically with a wide excision and sent for histopathological examination. The primary outcome was complete histopathological clearance of the LM from the surgical specimen. Patient-reported pain during illumination and the severity of the skin reaction after the PDT treatments were monitored as secondary outcomes.

RESULTS

The complete histopathological clearance rate was 7 out of 10 LMs (70%). The pain during illumination was tolerable, with the mean pain scores for the PDT sessions on a visual assessment scale ranging from 2.9 to 3.8. Some severe skin reactions occurred during the treatment period, however.

CONCLUSIONS

Ablative fractional laser-assisted PDT showed moderate efficacy in terms of histological clearance. It could constitute an alternative treatment for LM but due to the side effects it should only be considered in inoperable cases.

Diverse Environmental Microbiota as a Tool to Augment Biodiversity in Urban Landscaping Materials

Human activities typically lead to simplified urban diversity, which in turn reduces microbial exposure and increases the risk to urban dwellers from non-communicable diseases. To overcome this, we developed a microbial inoculant from forest and agricultural materials that resembles microbiota in organic soils. Three different sand materials (sieved, safety, and sandbox) commonly used in playgrounds and other public spaces were enriched with 5% of the inoculant. Skin microbiota on fingers (identified from bacterial 16S rDNA determined using Illumina MiSeq sequencing) was compared after touching non-enriched and microbial inoculant-enriched sands. Exposure to the non-enriched materials changed the skin bacterial community composition in distinct ways. When the inoculant was added to the materials, the overall shift in community composition was larger and the differences between different sand materials almost disappeared. Inoculant-enriched sand materials increased bacterial diversity and richness but did not affect evenness at the OTU level on skin. The Firmicutes/Bacteroidetes ratio was higher after touching inoculant-enriched compared to non-enriched sand materials. The relative abundance of opportunistic pathogens on skin was 40–50% before touching sand materials, but dropped to 14 and 4% after touching standard and inoculant-enriched sand materials, respectively. When individual genera were analyzed, Pseudomonas sp. and Sphingomonas sp. were more abundant after touching standard, non-enriched sand materials, while only the relative abundance of Chryseobacterium sp. increased after touching the inoculant-enriched materials. As Chryseobacterium is harmless for healthy persons, and as standard landscaping materials and normal skin contain genera that include severe pathogens, the inoculant-enriched materials can be considered safe. Microbial inoculants could be specifically created to increase the proportion of non-pathogenic bacterial taxa and minimize the transfer of pathogenic taxa. We recommend further study into the usability of inoculant-enriched materials and their effects on the bacterial community composition of human skin and on the immune response.

Hyperspectral imaging system in the delineation of Ill-defined basal cell carcinomas: a pilot study

BACKGROUND

Basal cell carcinoma (BCC) is the most common skin cancer in the Caucasian population. Eighty per cent of BCCs are located on the head and neck area. Clinically ill-defined BCCs often represent histologically aggressive subtypes, and they can have subtle subclinical extensions leading to recurrence and the need for re-excisions.

OBJECTIVES

The aim of this pilot study was to test the feasibility of a hyperspectral imaging system (HIS) in vivo in delineating the preoperatively lateral margins of ill-defined BCCs on the head and neck area.

METHODS

Ill-defined BCCs were assessed clinically with a dermatoscope, photographed and imaged with HIS. This was followed by surgical procedures where the BCCs were excised at the clinical border and the marginal strip separately. HIS, with a 12-cm² field of view and fast data processing, records a hyperspectral graph for every pixel in the imaged area, thus creating a data cube. With automated computational modelling, the spectral data are converted into localization maps showing the tumour borders. Interpretation of these maps was compared to the histologically verified tumour borders.

RESULTS

Sixteen BCCs were included. Of these cases, 10 of 16 were the aggressive subtype of BCC and 6 of 16 were nodular, superficial or a mixed type. HIS delineated the lesions more accurately in 12 of 16 of the BCCs compared to the clinical evaluation (4 of 16 wider and 8 of 16 smaller by HIS). In 2 of 16 cases, the HIS-delineated lesion was wider without histopathological confirmation. In 2 of 16 cases, HIS did not detect the histopathologically confirmed subclinical extension.

CONCLUSIONS

HIS has the potential to be an easy and fast aid in the preoperative delineation of ill-defined BCCs, but further adjustment and larger studies are warranted for an optimal outcome.

Short-term direct contact with soil and plant materials leads to an immediate increase in diversity of skin microbiota

Immune‐mediated diseases have increased during the last decades in urban environments. The hygiene hypothesis suggests that increased hygiene level and reduced contacts with natural biodiversity are related to the increase in immune‐mediated diseases. We tested whether short‐time contact with microbiologically diverse nature‐based materials immediately change bacterial diversity on human skin. We tested direct skin contact, as two volunteers rubbed their hands with sixteen soil and plant based materials, and an exposure via fabric packets filled with moss material. Skin swabs were taken before and after both exposures. Next‐generation sequencing showed that exposures increased, at least temporarily, the total diversity of skin microbiota and the diversity of Acidobacteria, Actinobacteria, Bacteroidetes, Proteobacteria and Alpha‐, Beta‐ and Gammaproteobacteria suggesting that contact with nature‐based materials modify skin microbiome and increase skin microbial diversity. Until now, approaches to cure or prevent immune system disorders using microbe‐based treatments have been limited to use of a few microbial species. We propose that nature‐based materials with high natural diversity, such as the materials tested here, might be more effective in modifying human skin microbiome, and eventually, in reducing immune system disorders. Future studies should investigate how long‐term changes in skin microbiota are achieved and if the exposure induces beneficial changes in the immune system markers.

Nature-derived microbiota exposure as a novel immunomodulatory approach

AIM

Current attempts to modulate the human microbiota and immune responses are based on probiotics or human-derived bacterial transplants. We investigated microbial modulation by soil and plant-based material.

MATERIALS & METHODS

We performed a pilot study in which healthy adults were exposed to the varied microbial community of a soil- and plant-based material.

RESULTS

The method was safe and feasible; exposure was associated with an increase in gut microbial diversity.

CONCLUSION

If these findings are reproduced in larger studies nature-derived microbial exposure strategies could be further developed for testing their efficacy in the treatment and prevention of immune-mediated diseases.

Half-lives of PAHs and temporal microbiota changes in commonly used urban landscaping materials

Background

Polycyclic aromatic hydrocarbons (PAHs) accumulate in urban soils, and PAH contamination can change soil microbial community composition. Environmental microbiota is associated with human commensal microbiota, immune system and health. Therefore, studies investigating the degradation of PAHs, and the consequences of soil pollution on microbial communities in urban landscaping materials, are crucial.

Methods

Four landscaping materials (organic matter 1, 2, 13 and 56%) were contaminated with PAHs commonly found at urban sites (phenanthrene, fluoranthene, pyrene, chrysene and benzo(b)fluoranthene) in PAH concentrations that reflect urban soils in Finland (2.4 µg g ^-1 soil dry weight). PAHs were analyzed initially and after 2, 4, 8 and 12 weeks by gas chromatography-mass spectrometry. Half-lives of PAHs were determined based on 12-weeks degradation. Bacterial communities were analyzed at 1 and 12 weeks after contamination using Illumina MiSeq 16S rRNA gene metabarcoding.

Results

Half-lives ranged from 1.5 to 4.4 weeks for PAHs with relatively low molecular weights (phenanthrene, fluoranthene and pyrene) in landscaping materials containing 1–2% organic matter. In contrast, in materials containing 13% and 56% organic matter, the half-lives ranged from 2.5 to 52 weeks. Shorter half-lives of phenanthrene and fluoranthene were thus associated with low organic matter content. The half-life of pyrene was inversely related to the relative abundance of Beta-, Delta- and Gammaproteobacteria, and diversity of Bacteroidetes and Betaprotebacteria. Compounds with higher molecular weights followed compound-specific patterns. Benzo(b)fluoranthene was resistant to degradation and half-life of chrysene was shorter when the relative abundance of Betaproteobacteria was high. Temporal microbiota changes involved increase in the relative abundance of Deltaproteobacteria and decrease in genera Flavobacterium and Rhodanobacter. Exposure to PAHs seems to adjust microbial community composition, particularly within class Beta- and Deltaproteobacteria.

Conclusions

In this study, PAH degradation depended on the organic matter content and bacterial community composition of landscaping materials. Contamination seems to alter bacterial community composition in landscaping materials depending on material type. This alteration includes changes in bacterial phyla associated with human health and immune system. This may open new possibilities for managing urban environments by careful selection of landscaping materials, to benefit health and wellbeing.

Urbanization Reduces Transfer of Diverse Environmental Microbiota Indoors

Expanding urbanization is a major factor behind rapidly declining biodiversity. It has been proposed that in urbanized societies, the rarity of contact with diverse environmental microbiota negatively impacts immune function and ultimately increases the risk for allergies and other immune-mediated disorders. Surprisingly, the basic assumption that urbanization reduces exposure to environmental microbiota and its transfer indoors has rarely been examined. We investigated if the land use type around Finnish homes affects the diversity, richness, and abundance of bacterial communities indoors. Debris deposited on standardized doormats was collected in 30 rural and 26 urban households in and near the city of Lahti, Finland, in August 2015. Debris was weighed, bacterial community composition determined by high throughput sequencing of bacterial 16S ribosomal RNA (rRNA) gene on the Illumina MiSeq platform, and the percentage of four different land use types (i.e., built area, forest, transitional, and open area) within 200 m and 2000 m radiuses from each household was characterized. The quantity of doormat debris was inversely correlated with coverage of built area. The diversity of total bacterial, Proteobacterial, Actinobacterial, Bacteroidetes, and Firmicutes communities decreased as the percentage of built area increased. Their richness followed the same pattern except for Firmicutes for which no association was observed. The relative abundance of Proteobacteria and particularly Gammaproteobacteria increased, whereas that of Actinobacteria decreased with increasing built area. Neither Phylum Firmicutes nor Bacteroidetes varied with coverage of built area. Additionally, the relative abundance of potentially pathogenic bacterial families and genera increased as the percentage of built area increased. Interestingly, having domestic animals (including pets) only altered the association between the richness of Gammaproteobacteria and diversity of Firmicutes with the built area coverage suggesting that animal ownership minimally affects transfer of environmental microbiota indoors from the living environment. These results support the hypothesis that people living in densely built areas are less exposed to diverse environmental microbiota than people living in more sparsely built areas.

Clinicopathological characteristics and cell cycle proteins as potential prognostic factors in myoepithelial carcinoma of salivary glands

Myoepithelial carcinoma (MCA) is a rare malignancy of salivary glands that was included in the WHO Classification of Head and Neck Tumors in 1991. MCA has shown a broad spectrum of clinical outcomes, but attempts to identify prognostic markers for this malignancy have not resulted in significant progress. Conventional histopathological characteristics such as tumour grade, nuclear atypia, mitotic index and cell proliferation have failed to predict the outcome of MCA. In this study, we reviewed the histopathology of 19 cases of MCA focusing on nuclear atypia, mitotic count, tumour necrosis, nerve and vascular invasion and occurrence of a pre-existing pleomorphic adenoma in connection to the MCA. Histopathological characteristics and clinical information were correlated with the immunohistochemical expression of cell cycle proteins including c-Myc, p21, Cdk4 and Cyclin D3. The proportion of tumour cells immunoreactive for these markers and their intensity of staining were correlated with clinical information using logistic regression, Kaplan-Meier and Cox regression. Using logistic regression analysis, cytoplasmic c-Myc expression was associated with the occurrence of metastases (P = 0.019), but limitations of semi-quantitation of immunostaining and the limited number of cases preclude definitive conclusions. Our data show that the occurrence of tumour necrosis predicts poor disease-free survival in MCA (P = 0.035).

Inferring the effects of potential dispersal routes on the metacommunity structure of stream insects: as the crow flies, as the fish swims or as the fox runs?

1. Metacommunity research relies largely on proxies for inferring the effect of dispersal on local community structure. Overland and watercourse distances have been typically used as such proxies. A good proxy for dispersal should, however, take into account more complex landscape features that can affect an organism's movement and dispersal. The cost distance approach does just that, allowing determining the path of least resistance across a landscape. 2. Here, we examined the distance decay of assemblage similarity within a subarctic stream insect metacommunity. We tested whether overland, watercourse and cumulative cost distances performed differently as correlates of dissimilarity in assemblage composition between sites. We also investigated the effect of body size and dispersal mode on metacommunity organization. 3. We found that dissimilarities in assemblage composition correlated more strongly with environmental than physical distances between sites. Overland and watercourse distances showed similar correlations to assemblage dissimilarity between sites, being sometimes significantly correlated with biological variation of entire insect communities. In metacommunities deconstructed by body size or dispersal mode, contrary to our expectation, passive dispersers showed a slightly stronger correlation than active dispersers to environmental differences between sites, although passive dispersers also showed a stronger correlation than active dispersers to physical distances between sites. The strength of correlation between environmental distance and biological dissimilarity also varied slightly among the body size classes. 4. After controlling for environmental differences between sites, cumulative cost distances were slightly better correlates of biological dissimilarities than overland or watercourse distances between sites. However, quantitative differences in correlation coefficients were small between different physical distances. 5. Although environmental differences typically override physical distances as determinants of the composition of stream insect assemblages, correlations between environmental distances and biological dissimilarities are typically rather weak. This undetermined variation may be attributable to dispersal processes, which may be captured using better proxies for the process. We suggest that further modifying the measurement of cost distances may be a fruitful avenue, especially if complemented by more direct natural history information on insect dispersal behaviour and distances travelled by them.

A comparative analysis reveals weak relationships between ecological factors and beta diversity of stream insect metacommunities at two spatial levels

The hypotheses that beta diversity should increase with decreasing latitude and increase with spatial extent of a region have rarely been tested based on a comparative analysis of multiple datasets, and no such study has focused on stream insects. We first assessed how well variability in beta diversity of stream insect metacommunities is predicted by insect group, latitude, spatial extent, altitudinal range, and dataset properties across multiple drainage basins throughout the world. Second, we assessed the relative roles of environmental and spatial factors in driving variation in assemblage composition within each drainage basin. Our analyses were based on a dataset of 95 stream insect metacommunities from 31 drainage basins distributed around the world. We used dissimilarity-based indices to quantify beta diversity for each metacommunity and, subsequently, regressed beta diversity on insect group, latitude, spatial extent, altitudinal range, and dataset properties (e.g., number of sites and percentage of presences). Within each metacommunity, we used a combination of spatial eigenfunction analyses and partial redundancy analysis to partition variation in assemblage structure into environmental, shared, spatial, and unexplained fractions. We found that dataset properties were more important predictors of beta diversity than ecological and geographical factors across multiple drainage basins. In the within-basin analyses, environmental and spatial variables were generally poor predictors of variation in assemblage composition. Our results revealed deviation from general biodiversity patterns because beta diversity did not show the expected decreasing trend with latitude. Our results also call for reconsideration of just how predictable stream assemblages are along ecological gradients, with implications for environmental assessment and conservation decisions. Our findings may also be applicable to other dynamic systems where predictability is low.

Daylight photodynamic therapy for actinic keratoses: a randomized double-blinded nonsponsored prospective study comparing 5-aminolaevulinic acid nanoemulsion (BF-200) with methyl-5-aminolaevulinate

BACKGROUND

Daylight-mediated photodynamic therapy (DL-PDT) using methyl-5-aminolaevulinate (MAL) is effective for thin, grade I, actinic keratoses (AK). There are no published studies of other photosensitizers used in DL-PDT.

OBJECTIVES

To compare the efficacy and adverse effects of 5-aminolaevulinic acid nanoemulsion (BF-200 ALA) with MAL in DL-PDT of grade I-III AKs.

METHODS

In 13 patients, 177 AKs were randomized symmetrically for a split-face prospective observer-blinded study and received either BF-200 ALA or MAL DL-PDT. Grade I AKs were treated once and grade II-III AKs twice with a 0·25-mm layer of photosensitizer precursors. Pain was assessed during and after the daylight exposure. Efficacy at 3 months was assessed clinically and histologically.

RESULTS

BF-200 ALA cleared 71/84 (84·5%) and MAL 69/93 (74·2%) of the AKs (P = 0·099), all grades responding equally, but with new AKs appearing during follow-up (n = 4, BF-200 ALA; n = 8, MAL). In per patient half-face analysis BF-200 ALA showed significantly higher clearance rates for grade I AKs than did MAL (P = 0·027), but for thicker grades, clearance was equal (P = 0·564). BF-200 ALA and MAL treatments resulted in 61·5% and 38·5% complete histological clearance (P = 0·375), respectively. p53 expression decreased by 54·4% and 33·7%, respectively (P = 0·552). Both treatments were nearly painless with similar adverse reactions and no difference in patient preference.

CONCLUSIONS

BF-200 ALA showed a trend towards improved efficacy results compared with MAL. Thicker lesions in both groups responded when treated repeatedly. Importantly, a thin 0·25-mm layer of the photosensitizer precursors was sufficient, which may lead to lower expense.

Untangling the relationships among regional occupancy, species traits, and niche characteristics in stream invertebrates

The regional occupancy and local abundance of species are affected by various species traits, but their relative effects are poorly understood. We studied the relationships between species traits and occupancy (i.e., proportion of sites occupied) or abundance (i.e., mean local abundance at occupied sites) of stream invertebrates using small-grained data (i.e., local stream sites) across a large spatial extent (i.e., three drainage basins). We found a significant, yet rather weak, linear relationship between occupancy and abundance. However, occupancy was strongly related to niche position (NP), but it showed a weaker relationship with niche breadth (NB). Abundance was at best weakly related to these explanatory niche-based variables. Biological traits, including feeding modes, habit traits, dispersal modes and body size classes, were generally less important in accounting for variation in occupancy and abundance. Our findings showed that the regional occupancy of stream invertebrate species is mostly related to niche characteristics, in particular, NP. However, the effects of NB on occupancy were affected by the measure itself. We conclude that niche characteristics determine the regional occupancy of species at relatively large spatial extents, suggesting that species distributions are determined by environmental variation among sites.

Metacommunity structuring in stream networks: roles of dispersal mode, distance type, and regional environmental context

Within a metacommunity, both environmental and spatial processes regulate variation in local community structure. The strength of these processes may vary depending on species traits (e.g., dispersal mode) or the characteristics of the regions studied (e.g., spatial extent, environmental heterogeneity). We studied the metacommunity structuring of three groups of stream macroinvertebrates differing in their overland dispersal mode (passive dispersers with aquatic adults; passive dispersers with terrestrial adults; active dispersers with terrestrial adults). We predicted that environmental structuring should be more important for active dispersers, because of their better ability to track environmental variability, and that spatial structuring should be more important for species with aquatic adults, because of stronger dispersal limitation. We sampled a total of 70 stream riffle sites in three drainage basins. Environmental heterogeneity was unrelated to spatial extent among our study regions, allowing us to examine the effects of these two factors on metacommunity structuring. We used partial redundancy analysis and Moran's eigenvector maps based on overland and watercourse distances to study the relative importance of environmental control and spatial structuring. We found that, compared with environmental control, spatial structuring was generally negligible, and it did not vary according to our predictions. In general, active dispersers with terrestrial adults showed stronger environmental control than the two passively dispersing groups, suggesting that the species dispersing actively are better able to track environmental variability. There were no clear differences in the results based on watercourse and overland distances. The variability in metacommunity structuring among basins was not related to the differences in the environmental heterogeneity and spatial extent. Our study emphasized that (1) environmental control is prevailing in stream metacommunities, (2) dispersal mode may have an important effect on metacommunity structuring, and (3) some factors other than spatial extent or environmental heterogeneity contributed to the differences among the basins.

Screening for endometrial cancer in asymptomatic postmenopausal women with conventional and colour Doppler sonography

OBJECTIVE

To evaluate endometrial thickness and uterine arterial flow measurement as predictors of endometrial cancer.

DESIGN

Prospective study among a cohort of women invited to age-adjusted, population-based breast cancer screening by mammography.

SETTING

City of Turku, Finland.

POPULATION

1074 postmenopausal women aged 57-61 years (mean 59 years).

METHODS

Conventional and colour Doppler sonography. Endometrial biopsy was taken when the endometrial thickness (double layer) was > or = 4.0 mm, if the uterine artery pulsatility index was < or = 1.0 or if there was a fluid accumulation in the endometrial cavity.

MAIN OUTCOME MEASURES

Detection of endometrial cancer in endometrial biopsy. Record linkage with the files of the Finnish Cancer Registry three and a half years after the first ultrasound examination. Major statistical results are based on the analysis of variance and logistic regression models.

RESULTS

An endometrial biopsy was taken from 291 women (27%). One woman had endometrial tuberculosis, three an endometrial polyp, 16 endometrial hyperplasia, three endometrial carcinoma (Stage Ib), and one had cervical carcinoma (Stage Ib). One woman was diagnosed as having endometrial cancer Stage Ib two and a half years after screening; she had refused further examination after a positive screen. A second endometrial cancer (Stage Ib) was diagnosed three years after a negative screening result.

CONCLUSION

Transvaginal sonography is confirmed to have a very high sensitivity for the detection of early endometrial carcinoma, but the specificity remains low. If endometrial cancer is to be detected at an early stage, further examinations should be carried out when the endometrial thickness is > or = 4.0 mm, especially when the woman has risk factors such as obesity, late menopause or current use of hormonal replacement therapy. Doppler sonography does not improve the detection of premalignant and malignant endometrial lesions compared with normal ultrasound.

Altered skin sensitivity in chronic itch: role of peripheral and central mechanisms

Nodular prurigo (NP) is a chronic skin disease causing severe itch of unknown origin in restricted skin areas surrounded by healthy skin areas. In the present investigation we studied cutaneous sensibility in five NP-patients and in five control subjects. Pain thresholds were determined with short argon laser pulses using two different sizes of stimulus surface (diameters 2 and 4 mm), tactile threshold with calibrated monofilaments and skin blood flow with a laser Doppler flowmeter. We also studied the effect of prolonged capsaicin treatment which should predominantly impair the function of nociceptive C-fibers. In both the itching and healthy skin areas the pain thresholds were lower in NP-patients than in healthy control subjects. Before capsaicin, an increase in stimulus area produced an equal decrease in pain threshold in all subjects. Following prolonged capsaicin treatment the pain threshold obtained with a large but not a small stimulus surface was elevated to control levels in NP-patients. Tactile thresholds in NP-patients were lower than in control subjects, and this abnormality was reversed by capsaicin. The basal skin blood flow level was more labile (fluctuating) in itching skin areas than in healthy skin areas of NP-patients. Capsaicin reduced blood flow fluctuation in the itching area. A lowered pain threshold not only in the itching area but also in the healthy skin area of NP-patients suggests that central convergence of itch and pain may contribute to increased pain sensitivity in chronic itch. Capsaicin-reversible abnormal fluctuation of the blood flow in the itching skin area might be explained by abnormal spontaneous activity of nociceptive peripheral nerve fibers and a consequent release of vasoactive agents from their terminals (axon reflex). The decreased tactile threshold and the elevation of it by capsaicin indicates that also the mechanisms underlying tactile sensibility are changed in chronic itch patients.

Endometrial fluid accumulation in asymptomatic postmenopausal women

Postmenopausal endometrial fluid accumulation was considered in the past to be related to cancer of the genital organs. Our purpose was to evaluate its prevalence, and its association with cervical stricture, use of hormone replacement therapy and endometrial pathology. A group of 1074 asymptomatic postmenopausal women aged 57-61 (mean 59) years was examined by transvaginal sonography with color Doppler imaging. Women who had an endometrial fluid accumulation underwent endometrial biopsy. Statistical analysis was mainly based on analysis of variance. Endometrial fluid accumulation was found in 134 women (12%). Women using only estrogen as hormone replacement therapy had a relative risk of 3.5 of endometrial fluid accumulation. In 12 women (9%), a cervical stricture precluded endometrial sampling. Six abnormal histopathological samples were found (5%): two endometrial polyps, one cystic hyperplasia, two adenomatous hyperplasias but only one adenocarcinoma. One further patient with endometrial cancer was registered by the Finnish Cancer Registry 2.5 years later in a woman who had refused endometrial sampling. Endometrial fluid accumulation is quite a common finding on transvaginal sonography among asymptomatic postmenopausal women and the process may be multifactorial. Cervical stricture is not the most important etiological factor. The use of estrogen replacement therapy increases the risk of endometrial fluid accumulation; however, it is rarely a sign of malignancy.

Influence of selective nerve fiber blocks on argon laser-induced thermal pain in the human skin

Influence of selective nerve fiber blocks on cutaneous pain induced by short argon laser pulses was studied in healthy humans. The minimal energy per surface area needed to produce a pain sensation was lower with a larger stimulus surface indicating spatial summation. Both compression of the peripheral nerve innervating the stimulus site (A-fiber block) and prolonged topical treatment of the stimulus site with 1% capsaicin (a predominant block of nociceptive C-fibers) produced an elevation of the pain threshold. Prolonged capsaicin treatment produced significantly higher pain thresholds than the compression block. Magnitude of the pain threshold elevation induced by nerve blocks varied depending on the area of the stimulus surface. Especially following prolonged capsaicin treatment, pain threshold elevations tended to be smaller with the larger area of the stimulus surface suggesting an enhanced spatial summation effect. Tactile thresholds were significantly elevated only by the compression block. The results indicate that nociceptive C-fibers have a significant contribution to the threshold sensation of pain induced by argon laser. Moreover, following impairment of function in nociceptive C-fibers, the spatial summation of argon laser-induced pain tends to be enhanced.

An attempt to attenuate experimental pain in humans by dextromethorphan, an NMDA receptor antagonist

Dextromethorphan (100 mg, orally), an NMDA receptor antagonist, did not significantly attenuate pain intensity or unpleasantness induced by experimental ischemia or by topical capsaicin in healthy human subjects, nor did it increase the threshold for heat pain or mechanical pain. A dose of 200 mg produced marked side effects. Thus, systemically administered dextromethorphan does not attenuate pain at clinically applicable doses in humans.

Transdermal estrogen for female stress urinary incontinence in postmenopause

OBJECTIVE

To evaluate the effect of transdermal estrogen for stress urinary incontinence in postmenopause.

STUDY DESIGN

An open within patient, dose-finding study with transdermal 17-beta-estradiol combined with cyclic medroxyprogesterone acetate was conducted over 9 months in 21 patients (mean age 57.3 years) suffering from urodynamically verified mild to moderate stress incontinence without detrusor instability.

RESULTS

Subjective improvement was noted in 16 out of 21 patients (76%). The dose level of 50 micrograms was better tolerated than 100 micrograms and sufficient enough to achieve continence.

CONCLUSION

Transdermal estrogen therapy plays an adjuvant role in conservative therapy for mild to moderate stress urinary incontinence in postmenopausal women.

Evaluation of ovarian findings in asymptomatic postmenopausal women with color Doppler ultrasound

BACKGROUND

To evaluate the prevalence and significance of abnormal ovarian findings in asymptomatic postmenopausal women, screening for ovarian cancer with color Doppler ultrasound was performed.

METHODS

One thousand three hundred sixty-four asymptomatic women aged 56-61 years (mean, 59 years) were examined by color Doppler sonography. Ninety-six percent of the examinations were transvaginal and 4% transabdominal. The criteria for abnormality were an ovarian volume 8 cm3 or greater, nonuniform echogenicity, and/or pulsatility index (PI) of the ovarian artery or tumor vessel, if present, 1.0 or less. Repeat sonograms were performed 1-3 months later on all patients with abnormal findings, and exploratory laparotomy was performed if a malignant tumor was suspected.

RESULTS

Abnormal ovarian findings were detected in 160 women (12%). At the time of repeat sonogram there were 28 persisting abnormalities (2%). At that time, the ovary was regarded as normal if it still contained a small clear cyst with an unchanged greatest dimension of less than 20 mm. Three women had a low PI value but all had also abnormal ovarian sonographic morphology. Two ultrasound-guided cyst punctures were performed and three patients had surgery; one benign serous cyst, one benign serous cystadenoma, and one serous cystadenoma of borderline malignancy were detected. The remaining abnormal findings disappeared or remained unchanged during a minimum follow-up of 2 years. One case of Stage IA ovarian cancer has been reported 2 years after a negative screening and one abdominal carcinomatosis 2 1/2 years after a negative screening result.

CONCLUSIONS

There is a high frequency of small ovarian cysts in asymptomatic postmenopausal women. A large percentage of these cysts regress spontaneously or remain unchanged. Transvaginal color Doppler ultrasound is an effective method for detecting these lesions. Color Doppler does not increase substantially the number of operations for benign reasons. However, as a primary screening modality, the conventional sonography seems to be quite sufficient.

A longitudinal study of screening for endometrial cancer by endometrial biopsy in diabetic females

Diabetics are at high risk of developing endometrial cancer; the relative risk of endometrial cancer in diabetics is fourfold in comparison to non-diabetic controls. The purpose of this longitudinal study was to evaluate the effectiveness of screening asymptomatic diabetic females in terms of the premalignant and malignant endometrial findings, and to try to determine the optimal screening interval. In 1980-1981, a group of 462 diabetic females was identified and registered. One half of them (237) was invited to be screened. Endometrial samples were taken by using Vabra aspiration. The results of this first randomized screening in 1980-1981 have been published elsewhere. At that time 124 females participated. The remaining 225 females acted as an unscreened control group. Eight years later (1988-1989), both groups were invited to be screened. The Pistolet aspiration method was used. At this stage, group 1 (screened in 1980-1981) consisted of 78 females, and group 2 (not screened in 1980-1981) consisted of 148 females. In 85% (193/226) of the females, the uterine cavity was reached with the Pistolet instrument; 96% of the females found the pain acceptable. In the group screened twice (group 1), no pathologic lesions of the endometrium were found in the second screening. In the group screened for the first time (group 2), one female had endometrial adenocarcinoma (0.8%), one had complex hyperplasia without atypia (0.8%) and four had endometrial polyps (3.3%). In 165 cases of 193, both a cytologic and a histologic specimen were available. In 130 cases (79%) the cytology was of class I, including the one endometrial adenocarcinoma. In three cases (2%) it was of class II and in one case (1%) of class III. Endometrial biopsy by Pistolet aspiration was a method highly acceptable by the patients for examining the endometrium. However, cytologic examination was not able to show the existing endometrial adenocarcinoma. One endometrial sampling of asymptomatic diabetic females during early menopause could detect the bulk of the occult, slowly progressing lesions of the endometrium. Such screeening might be most efficient in terms of cost-benefit ratio.

Effect of cocaine on sexual behaviour in male stumptail macaques (Macaca arctoides)

The effect of cocaine (0.01-1.0 mg/kg) on sexual behaviour was studied in four male stumptail macaques (Macaca arctoides). Following drug-saline control administration, the behaviour of the male monkey with a female was observed for 30 min in two different behavioural conditions; in one of the conditions the baseline sexual activity was low, and in the other it was high (partial or complete separation of the male and the female between the sessions, respectively). The reversal of the cocaine-induced effects was attempted by haloperidol (0.003-0.01 mg/kg), a dopamine-2-receptor antagonist. Cocaine (0.1-1.0 mg/kg) produced a highly significant dose-dependent suppression in the number of ejaculations. The cocaine-induced suppression of ejaculatory behaviour was completely reversed by haloperidol. Haloperidol at the dose range used did not in itself influence ejaculatory behaviour. The effect of cocaine on grooming, nonejaculatory mounting, aggression, or perineal investigations did not reach statistical significance. The possibility that cocaine at very low doses (0.01-0.1 mg/kg) might increase sexual activity was excluded in the behavioural condition with a low basal sexual activity. The results indicate that cocaine dose-dependently suppresses ejaculatory behaviour as a result of dopamine-2-receptor-mediated mechanisms. The cocaine-induced suppression of ejaculatory behaviour might be explained by the strong rewarding effect of cocaine alone.

Capsaicin-induced central facilitation of a sympathetic vasoconstrictor response to painful stimulation in humans

The effect of capsaicin, a compound selectively activating nociceptive primary afferent fibers, on a centrally mediated autonomic (sympathetic) vasoconstriction response to painful peripheral stimulation was studied in healthy human volunteers. Capsaicin (1%) was applied topically to the dorsal forearm and the threshold for eliciting a vasoconstriction response in the contralateral forefinger to painful electrical or thermal stimulation of the forearm skin adjacent to or remote from the capsaicin-treated region was determined with Laser Doppler flowmetry. Capsaicin produced a significant decrease of the threshold for the vasoconstriction response to painful electrical stimulation of the area of central allodynia; i.e., the skin area located adjacent to the capsaicin-treated region in which a light touch evoked an unpleasant sensation. Capsaicin did not change the threshold for the vasoconstriction response to painful heat stimuli applied to the area of central allodynia or to painful electric stimulation applied outside the borders of the allodynic area. Heart rate, blood pressure and heart vagal tone were not modified by capsaicin. It is concluded that a selective activation of nociceptive primary afferent fibers of the skin by capsaicin produces a central submodality-dependent facilitation of an autonomic vasoconstriction response to noxious stimulation in humans. This central facilitation can be explained by segmental excitability changes of afferent interneurons at the spinal cord level.

Steroid hormone receptors and flow cytometric DNA ploidy in ovarian carcinoma

The biochemical and immunohistochemical estrogen (ER) and progesterone receptor (PR) content and flow cytometric DNA ploidy was analyzed in five semimalignant and 35 malignant epithelial ovarian tumours. By biochemical assay, 67% of the tumours were ER-positive (> or = 5 fmol/mg protein) and 56% were PR-positive (> or = 10 fmol/mg protein). The corresponding values by immunohistochemical assay (with a HSCORE of 10 as the cutoff level) were 22% and 27%, respectively. DNA histogram measured from paraffin embedded specimens were diploid in 20% (7/35) and aneuploid in 80% (28/35) of the malignant tumours. All semimalignant tumours were diploid. The mean receptor values in the diploid and aneuploid tumours did not differ significantly and receptor-positive and receptor-negative tumours were evenly distributed in all stages and grades. In contrast, flow cytometric DNA ploidy was clearly associated with tumour stage (G2 = 10.52, Df = 3, P = 0.015) and histological differentiation (G2 = 20.57, Df = 3, P = 0.0001).

The risk of endometrial cancer in diabetic and hypertensive patients: a nationwide record-linkage study in Finland

The risk of endometrial cancer (EC) in diabetics and hypertensives was studied as part of the planning of a trial of the efficacy of screening for EC. Two nationwide registers, the Finnish Cancer Registry and the Social Insurance Institution's (SII) population register, were linked to obtain 1715 EC patients diagnosed during 1970-1974 with individually matched controls. Data on the right for state-reimbursed medication for diabetes or hypertension prior to the case's cancer diagnosis was obtained from the SII's population register and was used as indicator of the diseases in question. Diabetes was a strong and hypertension a relatively weak risk factor for EC. The relative risk for the association of EC with diabetes was 4.1 (95% confidence limits 2.7 and 6.9) and with hypertension 1.6 (95% confidence limits 1.3 and 2.1). Diabetics and hypertensives are identifiable risk groups for EC in Finland. Diabetics form a suitable target population for a trial of the efficacy of screening for EC.

A selective suppression of human pain sensitivity by carbon dioxide: central mechanisms implicated

The effect of breathing CO2 on somatic sensitivity was studied in human subjects. Healthy humans breathed room air, 100% O2, or CO2 (5% or 8% in O2). Thresholds to heat pain, mechanical pain, electrically evoked pain, and electrically evoked perception were measured using psychophysical techniques. Also, the effects on sensory and affective components of experimental ischaemic pain, alertness and on cardiovascular parameters were observed. In addition, the effect of CO2 on heat pain threshold was determined in the ischaemic limb to exclude the possibility that the threshold elevation was due to an action on primary afferent fibres. Naloxone (0.8 mg), dexamethasone (0.1 mg) or placebo (0.9% NaCl) were applied intravenously in double blind tests to reverse the threshold elevations. In an electrophysiological experiment the effect of CO2 on a spinal nociceptive flexion reflex evoked by an electric stimulus was measured. The CO2 produced a dose-dependent elevation of the heat pain threshold. Similarly, the sensory and affective components of experimental ischaemic pain were attenuated by CO2. The heat pain threshold was significantly elevated by CO2 in the ischaemic limb, also. However, there was no effect on thresholds to mechanically or electrically induced pain or perception thresholds to electrically evoked sensations. One hundred percent O, did not elevate the heat pain threshold. In double blind tests the heat pain threshold elevation was not significant when the naloxone or dexamethasone was administered. The threshold to electrically evoked spinal flexion reflex was not elevated by CO2. The CO2 at the current dose produced sedation, an increase in blood pressure but no change in heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Capsaicin-induced central facilitation of a nociceptive flexion reflex in humans

The effect of selective activation of nociceptive primary afferent fibers by capsaicin on a nociceptive lower limb flexion reflex was studied in healthy human subjects. Capsaicin (1%) applied topically to the skin produced a burning spontaneous pain sensation and allodynia in the treated region and in its immediate vicinity. Capsaicin applied to the distal innervation area of the sural or saphenous nerve produced a significant decrease of the threshold for the nociceptive limb flexion reflex induced by electric stimulation of the proximal sural nerve trunk, and this threshold decrease was rapidly attenuated by a cool compress concomitantly with the attenuation of the capsaicin-induced spontaneous pain. The latency of the flexion reflex response was not changed by capsaicin. The non-nociceptive H-reflex was not modified by capsaicin. It is concluded that a selective activation of nociceptive primary afferent fibers of the skin by capsaicin produces a central facilitation of a nociceptive flexion reflex in humans. This facilitation is selective on the nociceptive reflex and depends, at least partly, on the on-going afferent barrage in C-fibers.

Mass screening for endometrial cancer directed in risk groups of patients with diabetes and patients with hypertension

BACKGROUND

The interest in mass screening programs for the early detection of endometrial cancer (EC) has grown with the rising incidence of this disease. Preliminary programs directed at asymptomatic women with only one risk factor, i.e. age, have not been cost-effective.

METHODS

In the current study, 597 asymptomatic women from 45-69 years of age with diabetes and/or hypertension were screened by Vabra (Berkeley Medevices Inc., Berkeley, CA) aspiration.

RESULTS

Among the women with diabetes, 6.3% preinvasive lesions of the endometrium were found. This is significantly more than the rate among women with hypertension, which was 1.3% (P < 0.01).

CONCLUSIONS

Regular mass screening programs for the early detection of EC should be directed at asymptomatic diabetic women 45 years of age or older. This study does not indicate that similar screenings would be effective for women with hypertension.