Molecular Detection of Persistent Francisella tularensis Subspecies holarctica in Natural Waters.

Tularemia, caused by the bacterium Francisella tularensis, where F. tularensis subspecies holarctica has long been the cause of endemic disease in parts of northern Sweden. Despite this, our understanding of the natural life-cycle of the organism is still limited. During three years, we collected surface water samples (n = 341) and sediment samples (n = 245) in two areas in Sweden with endemic tularemia. Real-time PCR screening demonstrated the presence of F. tularenis lpnA sequences in 108 (32%) and 48 (20%) of the samples, respectively. The 16S rRNA sequences from those samples all grouped to the species F. tularensis. Analysis of the FtM19InDel region of lpnA-positive samples from selected sampling points confirmed the presence of F. tularensis subspecies holarctica-specific sequences. These sequences were detected in water sampled during both outbreak and nonoutbreak years. Our results indicate that diverse F. tularensis-like organisms, including F. tularensis subsp. holarctica, persist in natural waters and sediments in the investigated areas with endemic tularemia.

Defective suppression of Th2 cytokines by CD4CD25 regulatory T cells in birch allergics during birch pollen season.

BACKGROUND: CD4(+)CD25+ regulatory T cells suppress proliferation and cytokine production by human T cells both to self-antigens and exogenous antigens. Absence of these cells in human newborns leads to multiple autoimmune and inflammatory disorders together with elevated IgE levels. However, their role in human allergic disease is still unclear. OBJECTIVE: This study aimed to evaluate the capacity of CD4(+)CD25+ regulatory T cells to suppress proliferation and cytokine production outside and during birch-pollen season in birch-allergic patients relative to non-allergic controls. METHODS: CD4+ cells were obtained from blood of 13 birch-allergic patients and six non-allergic controls outside pollen season and from 10 birch-allergic patients and 10 non-allergic controls during birch-pollen season. CD25+ and CD25- fractions were purified with magnetic beads and cell fractions, alone or together in various ratios, were cultured with antigen-presenting cells and birch-pollen extract or anti-CD3 antibody. Proliferation and levels of IFN-gamma, IL-13, IL-5 and IL-10 were measured by thymidin incorporation and ELISA, respectively. Numbers of CD25+ cells were analysed by flow cytometry. RESULTS: CD4(+)CD25+ regulatory T cells from both allergics and non-allergics potently suppressed T cell proliferation to birch allergen both outside and during birch-pollen season. However, during season CD4(+)CD25+ regulatory T cells from allergic patients but not from non-allergic controls were defective in down-regulating birch pollen induced IL-13 and IL-5 production, while their capacity to suppress IFN-gamma production was retained. In contrast, outside pollen season the regulatory cells of both allergics and non-allergic controls were able to inhibit T-helper 2 cytokine production. CONCLUSION: This is the first study to show differential suppression of Th1 and Th2 cytokines, with CD4(+)CD25+ regulatory T cells from birch-pollen-allergic patients being unable to down-regulate Th2, but not Th1 responses during birch-pollen season.

No apparent reduction of gene flow in a hybrid zone between the West and North European karyotypic groups of the common shrew, Sorex araneus.

The common shrew, Sorex araneus, exhibits an unusually high level of karyotypic variation. Populations with identical or similar karyotypes are defined as chromosome races, which are, in turn, grouped into larger evolutionary units, karyotypic groups. Using six microsatellite markers, we investigated the genetic structure of a hybrid zone between the Sidensjö and Abisko chromosome races, representatives of two distinct karyotypic groups believed to have been separated during the last glacial maximum, the West European karyotypic group (western group) and the North European karyotypic group (northern group), respectively. Significant FST values among populations suggest some weak genetic structure. All hierarchical levels show similar levels of genetic differentiation, equivalent to levels of genetic structure in several intraracial studies of common shrew populations from central Europe. Notably, genetic differentiation was of the same order of magnitude between and within karyotypic groups. Although the genetic differentiation was weak, the correlation between genetic and geographical distance was positive and significant, suggesting that the genetic variation observed between populations is a function of geographical distance rather than racial origin. Hence, considerable chromosomal differences do not seem to prevent extensive gene flow.

Instrumental and dermatologist evaluation of the effect of glycerine and urea on dry skin in atopic dermatitis.

BACKGROUND/AIMS: Moisturising creams are useful treatment adjuncts in inflammatory dermatoses and have beneficial effects in the treatment of dry, scaly skin. The effects on dryness and skin permeability of a new moisturising cream with 20% glycerine was compared with its placebo and with a medicinally authorised cream with 4% urea (combined with 4% sodium chloride) in the treatment of dry skin. METHODS: Patients (n=109) with atopic dermatitis were treated for 30 days with a moisturiser in a randomised, parallel and double-blind fashion. Transepidermal water loss (TEWL) and skin capacitance were assessed instrumentally, and changes in the dryness of the skin were assessed by the dermatologist. RESULTS: No difference in TEWL was found between glycerine treatment and its placebo, whereas a lower value was found in the urea-treated area compared to the glycerine-treated area. No difference in skin capacitance was found. The clinical assessment of dryness showed urea to be superior to glycerine in treating the condition. CONCLUSIONS: Moisturising creams are different, not only with respect to composition but also with respect to their influence on skin as a barrier to water in patients with atopic dermatitis.

Leaching of concrete admixtures containing thiocyanate and resin acids.

There is an increasing concern about the emission of pollutants during the construction and lifetime of buildings. The leaching of concrete admixtures containing thiocyanate and resin acids was studied using standard leaching tests and chemical analysis. Ecotoxicological risk was assessed for each admixture. Thiocyanate leaching from concrete, with a chlorine-free accelerating admixture, was determined by ion chromatography. Of the total amount of thiocyanate added, 6-8% was emitted within 30 d. The thiocyanate diffusion curve indicates a fast dissolution process from the surface layer, followed by a slower continuous diffusion process. Thiocyanate exhibits both acute and chronic toxicity, which makes it of immediate environmental concern. Resin acid leaching from concrete test specimens containing an admixture of air-entraining agents with tall oil was determined by solid-phase extraction, methylation, and GC/MS. Of added resin acids, 10% was emitted over 143 d. The leaching curves for the resin acids indicate a continuous diffusion that is proportional to the square root of time and follows Fick's first law of diffusion. The chemical composition of the resin acids in the leachate demonstrates degradation and rearrangement of the resin acids during diffusion. Resin acids emitted from concrete are of environmental concern because they are persistent and have the ability to bioaccumulate in aquatic organisms.

Influence of TNT transformation on microbial community structure in four different lake microcosms.

After World War II, large amounts of obsolete ammunition were dumped in various lakes in Sweden. Trinitrotoluene, TNT, was one of the main components of the dumped explosives. In this study, four different lake microcosms originating from lakes where relatively large amounts of ammunition were dumped were used to mimic the effect of TNT release on the natural microbial community. Increased microbial growth was found in lake microcosms amended with TNT. However, negligible mineralization of TNT was detected, suggesting that TNT was not utilized as a carbon source, but as a nitrogen source. Random amplified polymorphic DNA (RAPD) analysis indicated that the TNT induced no significant differences in microbial community composition and therefore, no major changes in natural selection, despite the increased microbial growth in the presence of the compound. More than 95% of the added TNT bound irreversibly to the sediments, possibly as a result of microbial transformation to reactive metabolites that subsequently bound covalently to components of the sediment. The results, taken together, suggest that no permanent change in the microbial ecology occurred as a result of the TNT amendment. This was probably due partly to the transient exposure of the microbial communities to the TNT before it became irreversibly bound to the sediment, and partly to the fact that TNT was not a primary growth substrate that strongly affects natural selection.

Cultured human fibroblasts in agarose gel as a multi-functional control for immunohistochemistry. Standardization Of Ki67 (MIB1) assessment in routinely processed urinary bladder carcinoma tissue.

Immunohistochemistry (IHC) in clinical practice is hampered by lack of standardization and by subjectivity in interpretation and quantitation. This study aimed to develop a control system for IHC in routinely fixed and histoprocessed tissues. Such a system should be easy to handle in clinical practice and should reflect variations in fixation time, section thickness, section storage conditions, and staining protocols. In addition, in image analysis quantitation of immunostained tissues, when using classifiers computed on IHC-control images, the control system should be very stable. Cultured human fibroblasts were suspended in agarose, transferred into a length of tubing and stored at 4 degrees C. Three pieces of the cellgel control were separately fixed, histoprocessed, and paraffin-embedded as external controls. One piece was prepared together with each of 18 bladder carcinoma biopsies as internal controls. Slides with sections from the biopsy and all types of cellgel controls were stored at different temperatures and then stained using three different IHC protocols. The fibroblasts were homogeneously distributed in the agarose gel. Variation in section thickness did not influence immunostaining as evaluated by the MIB1 labelling index (MIB1 LI). The external controls decreased notably in MIB1 LI with increased fixation time. This was not seen in the 18 internal controls that were each fixed with a fresh biopsy. However, section storage and immunostaining conditions influenced the MIB1 expression equally in all control types and to a similar degree to the biopsies. Furthermore, colour-based image analysis quantitation of MIB1 LI in biopsies proved stable and independent of the control type used to compute the classifier.

Plasma thrombopoietin concentrations in response to platelet transfusion therapy.

Studies performed in rabbit and mouse models and in a limited number of human subjects, show that transfused platelets bind thrombopoietin (TPO) and decrease its concentration in the circulation. The aim of the present study was to further examine this relationship. The material comprised 12 patients receiving a total of 21 transfusions, as part of the routine clinical treatment. Blood samples were collected from the patients immediately before and 30 min after completion of the platelet transfusion, and the corrected platelet count increment (CCI) was calculated. A commercially available ELISA kit was used to determine plasma TPO concentrations. Statistically significant reductions in median TPO concentration were observed in response to the platelet transfusions. Patients who were refractory to platelet transfusions showed the slightest decrease in TPO concentration. As for the linear regression between change in TPO level and CCI, only borderline significance was observed. Thus, our findings support the concept that platelets can remove TPO from the circulation.

Applicability of rabbit microsatellite primers for studies of hybridisation between an introduced and a native hare species.

Introduced species may hybridise with relatives in the native fauna or flora and thereby compete for matings and transmit alien DNA. Such interference may contaminate unique genepools, disturb existing ecological balances and may ultimately result in the extinction of the native species. In Sweden, the introduced brown hare (Lepus europaeus Pall.) hybridise with the native mountain hare (L. timidus L.), both relatively common members of the present Swedish fauna. This hybridisation has resulted in the transmission of mitochondrial DNA from the mountain hare to the brown hare, but absence of species differences in karyotype and allozymes have prevented investigations of the amount of nuclear gene flow. More polymorphic genetic markers are needed to analyse evidence of hybridisation in the nuclear genome. The conservation of microsatellite loci across taxa usually enables PCR amplification of microsatellites in closely related species with the same primers. We have used five microsatellite primer pairs, developed for the European wild rabbit (Oryctolagus cuniculus L.) to amplify microsatellites in the two species of hare in Sweden. The obtained allelic variation was used to construct a genetic distance tree based on the amount of shared alleles between all pairs of individuals (shared-allele index). This method offered sufficient differences to arrange all individuals in two groups, one for each species. Identification of individual hybrids based on the number of alleles shared between the species is not possible with these five microsatellite markers.

Expression of envelope proteins of endogeneous C-type retrovirus on the surface of mouse and human oocytes at fertilization.

Retrovirus genomes express, among other products, the envelop (env) proteins SU (gp70) and TM (p15E). They coexist at the viral surface membrane and are able to promote immunosuppression and membrane fusion. In mouse oocytes, endogeneous retroviruses (ERV) genomes are expressed at fertilization, and antigen epitopes of the Moloney murine leukemia virus (MuLV) env protein gp70 are recognized in the cytoplasm of the oocytes before but not after fertilization. By using a panel of monoclonal antibodies (mAbs) raised against env components, we checked with laser scanning confocal microscopy (LSCM) whether gp70 and p15E were expressed also on the oocyte surface membrane (oolemma). Since we found that both mouse and human unfertilized oocytes expressed these ERV proteins on the oolemma and that the expression enfeebled significantly after fertilization, we assume that ERV genomes could play a role at the sperm-egg binding and fusion.

Improvement in skin barrier function in patients with atopic dermatitis after treatment with a moisturizing cream (Canoderm).

Patients with atopic skin show a defective barrier function both in rough and in clinically normal skin, with an increasing risk of developing contact dermatitis. Moisturizing creams are often used in the treatment of dry skin. The purpose of this study was to investigate the influence of treatment with a urea-containing moisturizer on the barrier properties of atopic skin. Fifteen patients with atopic dermatitis treated one of their forearms twice daily for 20 days with a moisturizing cream. Skin capacitance and transepidermal water loss (TEWL) were measured at the start of the study and after 10 and 20 days. On day 21 the skin was exposed to sodium lauryl sulphate (SLS) and on day 22 the irritant reaction was measured non-invasively. Skin capacitance was significantly increased by the treatment, indicating increased skin hydration. The water barrier function, as reflected by TEWL values, tended to improve (P = 0.07), and the skin susceptibility to SLS was significantly reduced, as measured by TEWL and superficial skin blood flow (P < 0.05). Thus, it seems that certain moisturizers could improve skin barrier function in atopics and reduce skin susceptibility to irritants. The mechanism and the clinical relevance need further investigation.

Expression of human endogenous retrovirus ERV3 (HERV-R) mRNA in normal and neoplastic tissues.

We investigated the mRNA expression of the human endogenous retrovirus ERV3 (HERV-R) in several normal and corresponding tumor tissues. The env gene of ERV3 is expressed as mRNA in several tissues. Comparison of ERV3 mRNA expression by Northern analyses, revealed a non-systematic variation. Expression was shown to be particularly high in the adrenal gland and some cases of lung cancer. This tissue-tropism should be seen in relation to the high expression previously found in syncytiotrophoblasts in placenta and sebaceous glands of the skin, suggesting profound influences by steroid hormonal regulation.

Automatic quantification of immunohistochemically stained cell nuclei based on standard reference cells.

A fully automatic method for quantification of images of immunohistochemically stained cell nuclei by computing area proportions, is presented. Agarose embedded cultured fibroblasts were fixed, paraffin embedded and sectioned at 4 microm. They were then stained together with 4 microm sections of the test specimen obtained from bladder cancer material. A colour based classifier is automatically computed from the control cells. The method was tested on formalin fixed paraffin embedded tissue section material, stained with monoclonal antibodies against the Ki67 antigen and cyclin A protein. Ki67 staining results in a detailed nuclear texture with pronounced nucleoli and cyclin A staining is obtained in a more homogeneously distributed pattern. However, different staining patterns did not seem to influence labelling index quantification, and the sensitivity to variations in light conditions and choice of areas within the control population was low. Thus, the technique represents a robust and reproducible quantification method. In tests measuring proportions of stained area an average standard deviation of about 1.5% for the same field was achieved when classified with classifiers created from different control samples.

Tissue and differentiation specific expression on the endogenous retrovirus ERV3 (HERV-R) in normal human tissues and during induced monocytic differentiation in the U-937 cell line.

ERV3 (HERV-R) is a complete, single copy human endogenous retrovirus located on the long arm of chromosome 7. The open reading frame in its envelope gene has been conserved during evolution but the gag and pol genes contain in-frame termination codons. To find a suitable experimental model system for analysis of the functions of the ERV3 genome, an extensive screening study of different normal and neoplastic human tissues was performed. Most tissues express low levels of the ERV3 env mRNA although high expression levels are observed in placenta, sebaceous glands, adrenals, testis, bronchial, epithelium and the monocytic cell line U-937. In U-937 cells the ERV3 env expression varied in a manner related to the differentiation status of the cells; being highest in the terminally differentiated non proliferating cells. U-937 cells can be induced to differentiate from the monoblastic to the mature monocyte/macrophage stage upon stimulation by several substances such as phorbolesters (TPA), Vitamin D3, Retinoic Acid (RA) and combinations of some cytokines. We conclude that the ERV3 locus is expressed in a tissue and differentiation specific way and that the U-937 cell line is a suitable model system to further analyze the proposed functions of ERVs such as immunomodulation, cell fusion and protection against exogenous retroviral infections.

DNA recovery and PCR quantification of catechol 2,3-dioxygenase genes from different soil types.

With the objective of monitoring xenobiotic degrading bacteria in soil, a method for rapid extraction of DNA from soil, amenable to amplification by PCR, was developed. The method was based on lysis by freeze-thawing and subsequent addition of sodium dodecyl sulfate (SDS), hexadecyltrimethylammonium bromide and proteinase K. The extraction method required 2 h and was tested on six different soils differing in organic content, water holding capacity and pH, including ones from which DNA extraction is difficult. DNA yields from the soils ranged from 6.1 to 54.0 micrograms of DNA per g soil. The efficiency and reproducibility of the DNA extraction method were evaluated by competitive PCR. The organic content in the soils was a major factor affecting the amount of obtained DNA amenable for amplification by PCR. A PCR primer-pair was designed on the basis of the known nucleotide sequences of several catechol 2,3-dioxygenase genes. The specificity of the primer-pair was demonstrated on different sequenced catechol 2,3-dioxygenase genes and on site-specific bacterial isolates from polycyclic aromatic hydrocarbon (PAH)-contaminated soil. The concentration of catechol 2,3-dioxygenase DNA in PAH-contaminated sediment undergoing an ex situ compost process was quantified by competitive PCR over a period of 16 weeks. The concentration of PAHs and catechol 2,3-dioxygenase DNA in the soil samples, was found to correlate.

Decreased growth rate and tumour formation of human anaplastic thyroid carcinoma cells transfected with a human thyrotropin receptor cDNA in NMRI nude mice treated with propylthiouracil.

The effect of the human TSH-receptor (TSHR) on the growth of human anaplastic thyroid carcinoma cells lacking the endogenous expression of TSHR, was studied both in vitro and in vivo in NMRI nude mice. Cells from a human anaplastic thyroid carcinoma cell line (C643) were transfected with a TSHR cDNA, and clones were isolated after neomycin selection. The expression of a functional receptor protein was ensured by analysis of the specific binding of 125I-TSH and measurement of TSH-induced cAMP. Incorporation of [3H]thymidine and increase in cell number was slightly inhibited by TSH in TSHR-expressing cells in vitro. In order to investigate whether the regained expression of a functional TSHR protein in C643 cells could influence the in vivo growth, cells were injected subcutaneously into NMRI nude mice. To manipulate the endogenous level of TSH, animals were given 6n-propyl-2-thiouracil (PTU; resulting in a high TSH level), T4 (a low TSH level) or no treatment (as a control). There seemed to be a TSH induced inhibition of tumour growth, since tumours in mice treated with PTU grew after a longer take rate and with a slower growth rate. The present results suggest a TSH-mediated growth inhibition in the TSHR-transfected C 643 anaplastic thyroid carcinoma cells.

Expression of the endogenous retrovirus ERV3 (HERV-R) during induced monocytic differentiation in the U-937 cell line.

ERV3 (HERV-R) is a complete human endogenous retrovirus located on the long arm of chromosome 7. LTR-env-gene-spliced mRNA of 9 and 3.5 Kb is widely expressed in human tissues and cells, but gag-pol mRNA has not been found. Further, the env gp70 gene contains an open reading frame throughout its length and its expression has recently been detected as a full-length protein. The highest expression of ERV3 detected so far is in placenta and the lowest in cytotrophoblasts and choriocarcinoma cell lines. In this report we have studied ERV3 mRNA and protein expression in the human monoblastic cell line U-937 during differentiation into monocytes/macrophages. Differentiation of U-937 cells was induced by 1,25a-dihydroxyvitamin D3 (vitD3), retinoic acid (RA), gamma interferon (IFN-gamma) and phorbol-myristate-acetate (PMA-TPA). The expression of ERV3 env mRNA was found to be differentiation-associated, with high expression detected in the late stages of monocytic development. Using TPA, the expression of ERV3 env was detected as 9- and 3.5-kb transcripts by Northern blotting, as mRNA by in situ hybridization and as a cytoplasmic 65-kDa protein by immunofluorescence and Western blots. Low levels of basal expression were found, with up-regulation of both message and protein at 24 to 48 hr after addition of TPA. Induction with vitD3, IFN-gamma and RA produced higher levels of mRNA at earlier time points. It is concluded that the U-937 cell line represents an excellent model system for further studies to study the relationship between ERV3 expression and cellular differentiation.

Effect of topically applied lipids on surfactant-irritated skin.

Moisturizers are used daily by many people to alleviate symptoms of dry skin. All of them contain lipids. It has been suggested that topically applied lipids may interfere with the structure and function of the permeability barrier. The influence of a single application of nine different lipids on normal skin and skin irritated by sodium lauryl sulphate (SLS) was studied in 21 healthy subjects. Parameters assessed were visible signs of irritation, and objectively measured cutaneous blood flow and transepidermal water loss (TEWL). The substances tested were hydrocortisone, petrolatum, fish oil, borage oil, sunflower seed oil, canola oil, shea butter, and fractions of unsaponifiable lipids from canola oil and shea butter. Water was included as a control. On normal skin, no significant differences in the effects of the test substances were found, whereas significant differences were observed when they were applied to SLS-irritated skin. The visible signs of SLS-induced irritation were significantly less pronounced after treatment with the sterol-enriched fraction from canola oil than after treatment with water. This fraction, and hydrocortisone, reduced cutaneous blood flow. Furthermore, application of hydrocortisone, canola oil, and its sterol-enriched fraction, resulted in significantly lower TEWL than with water. The other lipids had no effect on the degree of irritation. In conclusion, lipids commonly used in moisturizers may reduce skin reactions to irritants. Previous studies have shown that, in barrier perturbed skin, the synthesis of sterols is increased. The observed effects of canola oil and its fraction of unsaponifiable lipids on SLS-induced irritation suggest the possibility that they assisted the skin in supplying the damaged barrier with adequate lipids.

Elevated levels of the endogenous retrovirus ERV3 in human sebaceous glands.

ERV3 (HERV-R) is a complete human endogenous retrovirus located on the long arm of chromosome 7. Long terminal repeat-envelope (env) gene spliced mRNAs of 9 and 3.5 kb are widely expressed in human tissues and cells, but gag-pol mRNAs have not been found. Furthermore, the env gp70 gene contains an open reading frame throughout its length. The highest expression of ERV3 mRNA detected so far is in placenta and the lowest in choriocarcinoma cell lines. We have previously shown that the human monoblastic cell line U-937 and some normal and neoplastic tissues also express high levels of ERV3 env message by Northern blot analysis; however, this method does not distinguish between mRNA expression in different cell types in tissues. In this report, we have studied the ERV3 mRNA expression in specific cell types of human skin by in situ hybridization. We found high levels expression of ERV3 env mRNA in human sebaceous glands in normal skin and dermoid cysts of the ovary. In all glands, the expression is maximal in the periphery of the lobule and ceases towards the center in the region of characteristic holocrine secretion. Since it is known that the regulation of sebaceous glands is primarily via steroid hormones, particularly androgens, it is possible that expression of ERV3 is hormone dependent.