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Biomedical subjects

E Johansson

Publications and source records attributed to E Johansson.

At least 91 records · Page 5Linked to original sources
PubMed1998

Clinical and immunologic aspects of storage mite allergy.

Exposure to storage (nonpyroglyphid) mites has been increasingly recognized as a cause of asthma and rhinitis. Several species have been identified in Europe; e.g., Lepidoglyphus destructor, Acarus farris/siro, Tyrophagus spp., Glycyphagus domesticus, and Blomia tjibodas. Blomia tropicalis, on the other hand, predominates in subtropical and tropical areas. Studies from several countries have shown that IgE-mediated allergy in rural populations is of considerable importance and that storage mites are major allergens. Since these mites are found in homes, especially in regions with damp housing conditions, urban populations are at risk of becoming sensitized. Therefore, sensitization is not restricted only to those with occupational exposure. Several major allergens from storage mites have been identified and characterized. There seems to be a limited allergenic cross-reactivity between storage- and house dust mites. Molecular cloning has demonstrated that the Group 2 allergens from storage mites (Lep d 2 and Tyr p 2) show more than 40% sequence identity with the Group 2 allergens from Dermatophagoides spp. The availability of a large number of recombinant dust mite allergens will make it possible to investigate their homology and the number of allergens required for the diagnosis and treatment of storage mite allergy.

Allergens↗
PubMed1997

Identification of an active site in the antisecretory factor protein.

The antisecretory factor (AF) is a new regulatory protein, produced in the human pituitary gland, which reverses intestinal fluid secretion induced by cholera toxin. We have previously described the cDNA-cloning and characterization of the expressed gene. The aim of this study was to identify the region responsible for the antisecretory activity in the AF-molecule. The recombinant full-length AF has an increased ability to inhibit hypersecretion after treatment with trypsin, indicating that the activity of AF is achieved by smaller peptide fragments. To localize the active region of AF, we expressed truncated forms of the recombinant protein and examined their antisecretory activity against cholera toxin-induced fluid secretion in rat. Nine recombinant AF peptides and four smaller peptides made by solid phase synthesis were tested. Five of the peptides lacked all activity, whereas seven of them were highly active, a dose between 4 and 15 pmol causing a half-maximal inhibition. All the active peptides contained amino acid 36-42 of the AF sequence, whereas none of the inactive peptides contained this sequence. Our results suggest that the site of the antisecretory activity resides in a small region (I)VCHSKTR between position 35 and 42 of the AF molecule.

Amino Acid Sequence↗
PubMed1997

Frequency of Ha-ras-1 gene mutations inversely correlated with furan dose in mouse liver tumors.

Liver tumors were induced in infant male B6C3F1 mice by preweaning administration of furan, either as a single dose of 400 mg/kg body weight or six doses of 200 mg/kg body weight. Six doses of 200 mg/kg furan resulted in an increased incidence and multiplicity of liver tumors relative to the multiple-dose vehicle control group and the single-dose furan group. In the single-dose group, there was an increase in overall tumor multiplicity but not prevalence of liver tumors. After polymerase chain reaction amplification of isolated DNA, slot-blot oligonucleotide hybridization was used to screen for mutations at known mutational hot-spots in the first three exons of Ha-ras-1 (Hras1). The relative frequency of Hras1 activation was 82% in the 28 tumors analyzed from the single-dose group and 32% in the 28 tumors analyzed from the multiple-dose group. The lack of histomorphologic evidence of chronic cytotoxicity in the livers and the pattern of Hras1 activation suggest that a genotoxic mode of action is responsible for at least part of the hepatocarcinogenicity of furan in B6C3F1 mice. These findings confirm previously documented hepatocarcinogenicity of furan in B6C3F1 mice and provide evidence that carcinogen dose may influence the frequency of Hras1 activation in mouse liver tumors.

Adenoma↗
PubMed1997

Antisecretory factor suppresses intestinal inflammation and hypersecretion.

BACKGROUND: Antisecretory factor (AF) is a recently identified regulatory protein which inhibits the intestinal fluid secretion induced by cholera toxin. AIMS: To test the effect of AF on: (a) inflammation and hypersecretion induced by toxin A from Clostridium difficile; and (b) morphological changes and hypersecretion induced by okadaic acid (the blue mussel toxin) in rat intestinal mucosa. METHODS: Morphological changes and fluid accumulation were observed in intestinal loops challenged with 1 microgram of toxin A or 3 micrograms of okadaic acid administered before or after injection of 0.1 microgram of recombinant AF (rAF). RESULTS: The cytotoxic and inflammatory reaction caused by toxin A was abolished after treatment with rAF given either intraveneously or intraluminally prior to the toxin or one hour after the toxin. The intestinal fluid response induced by toxin A and okadaic acid was reduced 55-80% by rAF. However, the characteristic increase in goblet cells at the tips of villi in the okadaic acid treated mucosa was not inhibited by rAF. CONCLUSION: Results suggest that AF might be involved in protection against inflammation and in counteracting dehydration caused by enterotoxins. Both effects are probably mediated via the enteric nervous system.

Animals↗
PubMed1997

The impact of marital relationship on the rehabilitation process in a group of women with long-term musculoskeletal disorders.

This qualitative study investigated problems in the rehabilitation of women with long-term, musculoskeletal pain disorders. Data were collected by repeated semi-structured interviews and doctor-patient encounters during two years, and analysed in a gender perspective. The "marriage contract", i.e. the pattern of division of duties and power structure within the marital relationship, was of obvious importance to the implementation of rehabilitation measures. We explored situations where the rehabilitation measures disagreed with the terms and patterns in the "marriage contract". The participants' ways of coping with the contract in these delicate situations could be described as three type strategies; accepting the terms, negotiating for new terms, and breaking the contract. The crucial impact of the "marriage contract" and the type strategies on the rehabilitation process are exemplified.

Adaptation, Psychological↗
PubMed1997

Aminoglycosides do not improve the efficacy of cephalosporins for treatment of acute pyelonephritis in women.

A prospective, coordinated, randomized multicentre trial was conducted to determine whether tobramycin 160 mg intravenously (i.v.) once daily for 2 days would improve the efficacy of cefotaxime 1 g i.v. twice daily for 2 days followed by a 10-day course of oral cefadroxil 1 g twice daily, in the treatment of community-acquired acute pyelonephritis in women. Of 73 patients enrolled in the study, 51 could be evaluated according to the protocol. There were no significant differences in bacteriological cure rates between the combined treatment with tobramycin/cefotaxime and cefotaxime alone, either at short-term follow-up (63.0% vs 59.1%; 95% confidence interval (CI) for difference in proportions -23.4% to 31.2%), or up to 7 weeks after cessation of treatment (42.9% vs 52.2%; 95% CI, -18.0% to 36.6%). A modified intention-to-treat analysis showed no difference in clinical efficacy between the two regimens (68.6% vs 69.2%; 95% CI, -22.9% to 24.1%). Tobramycin seemed to enhance the resolution of inflammation by a more rapid decline in C-reactive protein levels. The high recurrence rates after treatment with beta-lactam antibiotics in this and previous studies of acute pyelonephritis may be explained by adverse ecological effects rather than failure to eradicate the infection.

Adult↗
PubMed1997

Allergenic crossreactivity between Lepidoglyphus destructor and Blomia tropicalis.

BACKGROUND: In general, the non-pyroglyphid mites Lepidoglyphus destructor and Blomia tropicalis show a different geographical distribution. Allergic sensitization to both species have been demonstrated in several investigations. However, whether this reflects cross-reactivity or dual sensitization is so far not known. OBJECTIVE: The aim of the study was to investigate the allergenicity and allergenic crossreactivity of L. destructor and B. tropicalis using sera from Sweden and Brazil. METHODS: Allergens in extracts of L. destructor and B. tropicalis were identified with SDS-PAGE and immunoblotting and the crossreactivity was studied by an immunoblot inhibition method. In addition to mite extracts, a recombinant major allergen of L. destructor, Lep d 2, was used. RESULTS: The extract prepared from L. destructor contained 21 IgE-binding components when using the Swedish or the Brazilian sera. A 15 kDa allergen was recognized by 85% of the Swedish sera and 78% of the Brazilian. The B. tropicalis extract exposed 23 IgE-binding components when the Brazilian sera were used and 19 when the Swedish sera were used. A total of 83% of the Brazilian sera and 80% of the Swedish sera identified a 14.5 kDa allergen. The IgE response of the Swedish serum pool to 10 B. tropicalis allergens was inhibited by L. destructor extract. Likewise, the response of the Brazilian serum pool to four different L. destructor allergens was inhibited by B. tropicalis extract. The recombinant Lep d 2 allergen inhibited 33% of the IgE binding of the Swedish serum pool to the 14.5 kDa allergen in the B. tropicalis extract. CONCLUSION: Crossreactivity with several proteins from L. destructor and B. tropicalis was demonstrated. The results suggest that a B. tropicalis 14.5 kDa allergen is antigenically crossreactive with recombinant L. destructor allergen Lep d 2.

Allergens↗
PubMed1996

Induction of the mouse ribonucleotide reductase R1 and R2 genes in response to DNA damage by UV light.

Ribonucleotide reductase is responsible for the production of deoxyribonucleotides required for DNA synthesis and consists of two nonidentical subunits, proteins R1 and R2. Here we show that the R1 promoter can be induced up to 3-fold, and the R2 promoter is induced up to 10-fold by UV light in a dose-dependent manner. This was demonstrated using serum-starved, synchronized G0/G1 mouse fibroblast 3T3 cells stably transformed with different R1 and R2 promoter-luciferase reporter gene constructs. R2 promoter activation requires a minimal promoter, containing a TTTAAA element plus the transcription start, and either three upstream DNA-protein binding regions or one proximal, NF-Y binding region. This is different from proliferation-specific activation of the R2 promoter. Using Northern blotting we show a preferential accumulation of the minor, 1. 6-kilobase R2 transcript in irradiated cells, whereas the levels of the major 2.1-kilobase transcript are unchanged. No R2 promoter activation was observed after treatment of mouse cells with agents reported to induce the ribonucleotide reductase genes in Saccharomyces cerevisiae such as hydroxyurea or methylmethane sulfonate. This indicates that activation of ribonucleotide reductase gene expression is specific for nucleotide excision repair in mammalian cells and not part of a general response to DNA damage.

3T3 Cells↗
PubMed1996

Anaerobic degradation of xenobiotics by organisms from municipal solid waste under landfilling conditions.

The potential for biological transformation of 23 xenobiotic compounds by microorganisms in municipal solid waste (MSW) samples from a laboratory scale landfill reactor was studied. In addition the influence of these xenobiotic compounds on methanogenesis was investigated. All R11, 1,1 dichloroethylene, 2,4,6 trichlorophenol, dimethyl phthalate, phenol, benzoate and phthalic acid added were completely transformed during the period of incubation ( > 100 days). Parts of the initially added perchloroethylene, trichloroethylene, R12, R114, diethyl phthalate, dibutyl phthalate and benzylbutyl phthalate were transformed. Methanogenesis from acetate was completely inhibited in the presence of 2,5 dichlorophenol, whereas 2,4,6 trichlorophenol and R11 showed an initial inhibition, whenafter methane formation recovered. No transformation or effect on the anaerobic microflora occurred for R13, R22, R114, 3 chlorobenzoate, 2,4,6 trichlorobenzoate, bis(2 ethyl)hexyl phthalate, diisodecyl phthalate and dinonyl phthalate. The results indicate a limited potential for degradation, of the compounds tested, by microorganisms developing in a methanogenic landfill environment as compared with other anaerobic habitats such as sewage digestor sludge and sediments.

Anaerobiosis↗
PubMed1996

Staff and patient attitudes to tuberculosis and compliance with treatment: an exploratory study in a district in Vietnam.

SETTING: The study, a collaboration between the National Tuberculosis Institute, Hanoi, Vietnam and the Karolinska Institutet, Stockholm, Sweden, was carried out in a district of Quang Ninh Province in North Vietnam. OBJECTIVES: To describe tuberculosis (TB) services, attitudes of staff, and attitudes of patients considered as defaulters to TB treatment. DESIGN: Two focus group discussions were carried out with staff at the district hospital. Ten defaulter patients were interviewed in their homes. RESULTS AND CONCLUSIONS: This exploratory study has revealed some important aspects of staff and patients' attitudes to TB and its treatment. Tuberculosis is considered a 'dirty' disease, which mainly affects poor people. There is a tendency to avoid telling others about it. Obvious symptoms are explained as 'being overworked'. A patient with TB feels 'less respected' by others. The social stigmatization leads to delays in seeking medical care, often only after self-medication: anti-tuberculosis drugs can be bought without prescription in various pharmacies. The patient's economic situation is also an important determinant of compliance and non-compliance. These factors need to be taken into consideration in TB control in Vietnam.

Adolescent↗
PubMed1996

ELISA method for detection of mite allergens in barn dust: comparison with mite counts.

ELISA (enzyme-linked immunosorbent assay) inhibition with a monoclonal antibody (mAb) (42B6) to Lepidoglyphus destructor was used to detect and quantify the storage-mite allergens in 30 dust samples collected from barns. Regarding the mite fauna, microscopic inspection of the barn dust and mite counts showed that L. destructor infested all 30 barns investigated (range 430-195 400 mites/g dust). In 29/30 barns, L. destructor constituted more than 70% of the Astigmata species. Acarus siro was found in 26 samples, the highest value being 16155 mites/g. No Dermatophagoides species were found. As to mites of the suborder of Prostigmata, species belonging to seven different families were detected. Besides the predominant L. destructor, allergens derived from other storage mites such as Glycyphagus domesticus, A. siro, and Tyrophagus putrescentiae have previously been assessed by this ELISA method. The correlation between number of mites and concentrations of mite antigen as measured by ELISA was assessed by linear regression (r2 = 0.83). Thus, inhibition of mAb 42B6 in ELISA would seem to offer a simple and reliable method to detect levels of dust-mite species belonging to the Acaridae and Glycyphagidae families.

Agricultural Workers' Diseases↗
PubMed1995

The TATA-less promoter of mouse ribonucleotide reductase R1 gene contains a TFII-I binding initiator element essential for cell cycle-regulated transcription.

Mammalian ribonucleotide reductase shows S-phase specific expression and consists of two non-identical subunits, proteins R1 (large subunit) and R2 (small subunit). A comparison between the human and mouse TATA-less R1 gene promoters revealed four highly conserved DNA regions, while the remaining sequence showed a low degree of conservation. Two regions, alpha and beta, were earlier identified as protein binding regions in the mouse R1 promoter by using DNase footprinting technique. The two new regions are located to the transcription start and to a DNA sequence about 40 base pairs downstream from the start. Gel shift assays using TFII-I antibodies and competition with an oligonucleotide representing the terminal deoxynucleotidyl transferase inhibitor element identified the start region as a TFII-I binding initiator element. The conserved downstream region, called gamma, also formed specific DNA-protein complexes in gel shift assays. Functional studies, using synchronized cells stably transformed by R1 promoter-luciferase reporter gene constructs, indicated that the initiator and the gamma elements together were necessary for cell cycle-regulated R1 promoter activity. Earlier published data, indicating Sp1 binding to the R1 alpha/beta regions, could not be confirmed, suggesting that the R1 initiator element may function independent of Sp1.

3T3 Cells↗
PubMed1995

Molecular cloning and expression of a pituitary gland protein modulating intestinal fluid secretion.

Antisecretory factor (AF) is a protein known to inhibit intestinal fluid secretion induced by cholera toxin. cDNA clones, expressing immunoreactivity to AF were isolated from a human pituitary gland library and sequenced. The sequence contained 1309 base pairs plus a poly(A) tail; Northern blot analysis of pituitary RNA confirmed this size. One large open reading frame was found to code for 382 amino acids. The protein was expressed in pGEX-lambda 1T/Escherichia coli and purified. The recombinant AF was extremely potent, 9 ng (2.10(-13) mol), giving a significant antisecretory activity against cholera toxin-induced fluid secretion in rat. Antiserum against recombinant AF was used in immunohistochemical and Western blot analysis. Sections from human pituitary glands manifested specific intracellular staining in cells exclusively located in the anterior part. Both recombinant AF and AF extracted from pituitary gland appeared in SDS-polyacrylamide to have a molecular mass of 60 kDa, although the renal value was 41 kDa. The protein sequence manifested homology (29% identity) with one protein, a putative Saccharomyces cerevisiae 30-kDa protein of unknown function.

Amino Acid Sequence↗
PubMed1995

Development and characterization of essential fatty acid deficiency in human endothelial cells in culture.

We induced an essential fatty acid deficiency (EFAD) in human umbilical vein endothelial cells by culture in medium with 20% (vol/vol) delipidated fetal calf serum. EFAD, reflected by decreased cellular linoleic acid (18:2 omega 6) and arachidonic acid (20:4 omega 6) and emergence of the oleic acid derivative 5,8,11-eicosatrienoic acid (20:3 omega 9; Mead's acid), was evident after 1 week of culture and became pronounced after 2 weeks. Beyond that time point, control cells (cultured in 20% normal fetal calf serum) grew deficient of 18:2 omega 6, and EFAD cells died. 18:2 omega 6 addition to EFAD cells resulted in dose-dependent increases of 18:2 omega 6 and 20:4 omega 6. 20:4 omega 6 or 5,8,11,14,17-eicosapentaenoic acid (20:5 omega 3) additions resulted in normalization of these acids, and conversion of 20:5 omega 3 to 4,7,10,13,16,19-docosahexaenoic acid (22:6 omega 3) was noted. Agonist-induced increases in concentrations of prostacycline (prostaglandin I2; PGI2) and cytosolic Ca2+, [Ca2+]i, were reduced in EFAD cells and not restored by 18:2 omega 6 or 20:4 omega 6 additions. Change of the medium in EFAD cultures 1 day before the experiments decreased 20:3 omega 9 and normalized the PGI2 production and [Ca2+]i changes, whereas addition of 20:3 omega 9 to control cells impaired the [Ca2+]i response, indicating a suppressive effect of 20:3 omega 9. Thus, EFAD in endothelial cells is associated with abnormalities of eicosanoid and second-messenger production partly attributable to 20:3 omega 9 accumulation. Moreover, the gradual emergence of 18:2 omega 6 deficiency in regularly grown control cells underlines the need for careful analysis of fatty acids in long-term cell cultures.

Calcium↗
PubMed1995

IgG1 and IgG4 antibody responses to the dust mite Lepidoglyphus destructor in a naturally exposed farming population.

The natural humoral immune response to the dust mite Lepidoglyphus destructor was assessed by comparing the IgG1 and IgG4 responses elicited in allergic (n = 44) and healthy (n = 16) individuals in a farming population chronically exposed to this allergen. With the aid of an immunoblotting technique and ELISA, the sera were analyzed for anti-L. destructor antibodies. While the majority of sera from the allergy group displayed several bands for both IgG1 and IgG4, the nonatopic healthy group was negative as analyzed in immunoblotting. When they were analyzed in ELISA, there was a significantly higher response in the allergy group than in the healthy group for IgG4, but not for IgG1. Taken together, these results imply that the immune system of individuals spared from allergic reactions to L. destructor not only lacks IgE antibodies but also seems largely to "ignore" these allergens/antigens despite exposure.

Agriculture↗
PubMed1994

The use of the GRID program in the 3-D QSAR analysis of a series of calcium-channel agonists.

The use of GRID in the 3-D QSAR analysis of a series of calcium-channel agonists is described. Partial least-squares analysis of GRID maps showing the interaction energy between an alkyl hydroxyl probe and a series of agonists in 3-D space generated a predictive quantitative model of the variation of biological activity. The macroscopic descriptors CLOGP and CMR were included in the analysis, and the importance of appropriate block scaling is highlighted. The discussion highlights the interpretation of the resulting regression maps, and the steric, electrostatic, lipophilic, and hydrogen-bonding preferences of the calcium-channel receptor are identified.

Animals↗