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Biomedical subjects

B Niklasson

Publications and source records attributed to B Niklasson.

At least 91 records · Page 5Linked to original sources
PubMed1987

Nephropathia epidemica: incidence of clinical cases and antibody prevalence in an endemic area of Sweden.

The incidence of nephropathia epidemica (NE) was compared with the NE antibody prevalence in normal population in a highly endemic area of Sweden (Västerbotten county). The antibody prevalence rate in the oldest age groups were found to be 14 and 20 times higher than the accumulated life-risk of being hospitalized with NE for men and women respectively. Whether the infection in persons not admitted to hospital is subclinical, atypical or clinically fulminant, remains to be determined.

Adult↗
PubMed1987

Epidemiology of nephropathia epidemica in Sweden.

A comprehensive study of nephropathia epidemica (NE), caused by Puumala virus, was conducted in Sweden. Human sera from residents of various regions of Sweden were examined for antibody to Puumala virus, and the incidence of NE was determined. Small mammals were captured at locations throughout Sweden and were examined for antibody to Puumala virus and for antigen. The human serosurvey found the highest prevalence rates and the highest incidence rates in northern Sweden. The bank vole was found to be the most-abundant rodent, as well as the species most frequently positive for antibody. Antibody-positive voles were restricted to the northern two-thirds of the country, an area corresponding to that where most human disease was noted. These results suggest that the bank vole is the principal host of Puumala virus in Sweden and clearly establish the region near 64 degrees N as highly endemic for NE in humans.

Animals↗
PubMed1986

Global survey of antibody to Hantaan-related viruses among peridomestic rodents.

A global serological survey of rodents was conducted to determine the distribution and prevalence of antibody to Hantaan-related viruses, which are the causative agents of haemorrhagic fever with renal syndrome (HFRS) in man. Over 1700 rodent sera from more than 20 sites worldwide were examined by immunofluorescent antibody assay. High-titred positive sera were further tested by plaque reduction neutralization tests with prototype Hantaan virus and urban rat-associated Hantaan-like virus. Antibody-positive rodents were found in most, but not all, sites sampled. The highest antibody prevalence rates were found in Baltimore, MD, USA and Bélem, Brazil, and Rattus norvegicus was the species most often found positive. Bandicota indica and B. bengalensis, species previously not recognized as hosts of hantaviruses, were also positive. Neutralization tests detected antibody in Rattus sera specific for urban rat-associated Hantaan-like virus, but failed to establish the specificity of antibody in Bandicota sera. These results indicate that Hantaan-related viruses exist beyond the currently recognized boundaries of HFRS in man and suggest that human HFRS-like disease might be occurring in other areas of the world where rodent-human contact is common.

Africa↗
PubMed1986

Seasonal activity of mosquitoes in an Ockelbo disease endemic area in central Sweden.

In the Sässman area, province of Hälsingland, Sweden, mosquitoes were sampled in 1983 from aquatic habitats, overwintering sites, cattle sheds, human bait, with UV-light traps, rabbit-, guinea-pig-, hen-, dove- and unbaited suction traps and similarly baited net traps. Anopheles beklemishevi, An. messeae, Aedes cantans, Ae. cataphylla, Ae. cinereus, Ae. communis, Ae. diantaeus, Ae. excrucians, Ae. hexodontus, Ae. intrudens, Ae. leucomelas, Ae. pionips, Ae. punctor, Ae. vexans, Culex pipiens, Cx. torrentium, Cx. territans, Culiseta alaskaensis, Cs. bergrothi, Cs. morsitans, Cs. ochroptera and Mansonia richiardii were recorded as new to the province. Data are presented on the ecology including seasonal abundance and seasonal blood-feeding activity of each species. Ockelbo disease, caused by a virus indistinguishable from Sindbis virus, is prevalent amongst humans in the study area. The ecological and behavioral potential of species of Culex, Culiseta and Aedes to transmit the virus is discussed.

Animals↗
PubMed1985

Rift Valley fever virus vaccine trial: study of neutralizing antibody response in humans.

The serological response to immunization with a formalin inactivated Rift Valley fever (RVF) vaccine was studied in 963 Swedish UN soldiers serving in the Sinai peninsula. Antibody titres were determined with a plaque reduction neutralization test (PRNT). Attempts were made to give all soldiers three injections (1 ml s.c. days 0, 7-10 and 28-30) but 128 soldiers received only two injections. In a group of 51 fully vaccinated individuals, repeated blood samples were collected. Fifty of the vaccinees seroconverted. Serum collected six weeks after the first vaccination revealed the highest antibody titres. The geometric mean titre then decreased rapidly during the following two weeks. Six months after vaccination sera were collected from 433 vaccinees who had received three injections and 379 had antibodies detectable by PRNT (88% PRNT greater than or equal to 10). The corresponding figures one and two years after vaccination were 223 seropositives out of 255 (91% PRNT greater than or equal to 10) and 91 out of 123 (74% PRNT greater than or equal to 10), respectively. Multiple stepwise regression showed that three injections gave a better antibody response than two injections. This analysis also showed that the magnitude of the antibody response was reduced with increasing age. Slight, local and general side effects were reported in 6% of the vaccinees and these reactions occurred in individuals with relatively higher antibody response.

Antibodies, Viral↗
PubMed1985

Thin layer chromatography and high pressure liquid chromatography of musk ambrette and other nitromusk compounds including photopatch studies.

For qualitative and quantitative analysis of musk ambrette and 4 other nitromusk compounds (musk ketone, moskene, musk tibetine, musk xylene) thin layer chromatography (TLC) and high pressure liquid chromatography (HPLC) techniques were developed. By TLC a reasonable separation was obtained and the limit of detection was 2-5 x 10(-7) g. By HPLC the separation was even better and the limit of detection for musk ambrette was 2 x 10(-9) g. The correlation between the amount of musk ambrette/ketone and the HPLC peak was linear. The TLC and HPLC techniques were used to demonstrate the presence of nitromusks in several commercial products, mainly aftershave lotions and eau-de-toilettes preparations. By ultraviolet spectrophotometry, absorption spectra were studied for the nitromusk compounds. The absorption maximum for musk ambrette was at 264 nm, that for moskene at 253 nm. Photopatch testing was carried out in 13 patients photoallergic to musk ambrette. Only 3 patients also reacted to other nitromusks. Photoallergey to musk ketone and musk tibetine is reported for the first time.

Chromatography, High Pressure Liquid↗
PubMed1984

The sensitizing potential of di-(meth)acrylates based on bisphenol A or epoxy resin in the guinea pig.

Most composite materials in dentistry used today, contain resins based on dimethacrylates. BIS-GMA [2,2-bis-(4-(2-hydroxy-3-methacryloxypropoxy)phenyl)propane], the addition reaction product of bisphenol A and glycidyl methacrylate or an epoxy resin and methacrylic acid, is used most extensively. More recently, dimethacrylates based on bisphenol A, with various chain lengths have appeared on the market as a substitute for or in addition to BIS-GMA. Such compounds are BIS-MA [2,2-bis-(4-(methacryloxy)phenyl)propane], BIS-EMA [2,2-bis-(4-(2-methacryloxyethoxy)phenyl)propane] and BIS-PMA [2,2-bis-(4-(3-methacryloxypropoxy)phenyl)propane]. Increasing interest in the radiaton cure of coatings and printing inks have focused attention on these substances and on epoxy diacrylates as radiation-curable resins. The sensitizing capacity of the different acrylates based on bisphenol A or epoxy resin have been investigated with the guinea pig maximization test. The pattern of simultaneous reactivity of the compounds was also studied. Epoxy diacrylate [2,2-bis-(4-(2-hydroxy-3-acryloxy-propoxy)phenyl)propane], BIS-EMA and BIS-MA are shown to be strong sensitizers, while the linear fraction of BIS-GMA and its isomers and BIS-PMA have none or a low sensitizing capacity. The impurities in the BIS-GMA and BIS-MA batches seem to have high allergenic potential. These results stress the importance of a pure substance when discussing allergenicity and cross reactions.

Acrylates↗
PubMed1984

Influence of the vehicle on elicitation of contact allergic reactions to acrylic compounds in the guinea pig.

Many factors can influence the elicitation of hypersensitivity reactions in guinea pigs and humans. The effect which the vehicle might have on the test response in guinea pigs sensitized with various acrylic compounds, using the "guinea pig maximization test", has been investigated. A marked decrease in the number of positive animals was seen when acetone was used as test vehicle, compared to petrolatum. The same result was seen with alcohol as vehicle, when neopentyl glycol diacrylate (NPGDA) was used as an acrylic monomer model. The patch test locations on the guinea pig flank, also affected the test response. Half of the animals did not react when challenged near the abdomen, compared to a test site near the back. By means of HPLC-analysis, the possible adsorption of the acrylic monomer to the aluminium chamber or filter paper disc, was analysed. Our findings did not indicate that adsorption occurs. A decrease in the amount of acrylic monomer in the chamber with increasing time, was noted. There was a marked difference in the monomer residue between solutions with (darkness) and without (daylight) inhibitor. The monomer decrease was also more affected by an aluminium surface than a glass or filter paper surface. Aluminium oxide probably enhances the polymerization process. The discrepancy between the test results in this study, when petrolatum and acetone were used as test vehicles, is due to a polymerization process of the acrylic compounds. Thus, the petrolatum vehicle probably prevents polymerization of the acrylic monomer.

Acetone↗
PubMed1984

Detection of human immunoglobulins G and M antibodies to Rift Valley fever virus by enzyme-linked immunosorbent assay.

Rift Valley fever virus (RVFV) is an important human and animal pathogen in Africa and has been responsible for infections in travelers. Because of the aerosol infectivity and risk of dissemination of the virus, a need exists for simple, safe, serological tests for diagnosis. An enzyme-linked immunosorbent assay (ELISA) was developed to detect RVFV-specific immunoglobulins (immunoglobulin G [IgG] and IgM). In the test, a betapropiolactone-inactivated, sucrose-acetone-extracted, suckling mouse liver RVFV antigen was captured by mouse RVFV antibodies adsorbed to polystyrene plates. The test sample (human serum) was then added, and the binding of specific antibodies was indicated by alkaline phosphatase-conjugated swine anti-human IgG or IgM. A mu-capture IgM ELISA was also developed by using polystyrene plates coated with goat anti-human IgM incubated successively with serum sample, RVFV antigen, and indicator antibodies. The ELISA for RVFV-specific IgG proved to be more sensitive than hemagglutination inhibition or complement fixation tests and almost as sensitive as the plaque reduction neutralization test in detecting specific antibodies in human sera after vaccination. The two ELISA IgM tests could detect specific IgM antibodies during the first 6 weeks after RVFV vaccination. Three injections of inactivated vaccine were given on days 0, 6 to 8, and 32 to 34. ELISA IgM values for sera obtained on days 6 to 8 were negative or in the lower range of significance, on days 32 to 34 they were strongly positive, and on days 42 to 52 they were waning. Later sera were negative. The plague reduction neutralization test was negative on days 6 to 8 but rose progressively in later samples. These findings suggest that the three doses of RVFV vaccine induce a prolonged primary antibody response. The ELISA IgM could become an important tool for early diagnosis in acute human infection. A number of African sera, some of which were positive for RVFV by plaque reduction neutralization test, were also tested by ELISA IgG. There was good agreement between both tests.

Animals↗
PubMed1984

Ockelbo disease in Sweden: epidemiological, clinical, and virological data from the 1982 outbreak.

An outbreak of Ockelbo disease, a syndrome with rash, arthralgia and moderate fever reactions, which occurred in Sweden 1982 is described. A virus, designated Edsbyn 5/82, isolated from mosquitoes and closely related to Sindbis virus (Togaviridae: Alphavirus) is the probable etiologic agent. Sixty-five patients with typical clinical manifestations of the disease became ill in August 1982 and exhibited antibody titer rises against both Edsbyn 5/82 and Sindbis viruses by indirect immunofluorescence and the mixed hemadsorption technique. With the latter method, but not by the neutralization tests, antibody titers were significantly higher against Edsbyn 5/82 virus than against Sindbis virus. Most cases occurred in central Sweden between the 60th and 63rd parallels. The frequency of antibody in healthy individuals (blood donors) within the endemic area was 2-3% and in foci with high incidence, antibody positivity reached 8%. Antibody frequencies continuously decreased south and north of this area. Antibody decline was followed in a group of 12 patients who had Ockelbo disease in 1981. Mixed hemadsorption titers were 4-6 times higher against Edsbyn 5/82 than against Sindbis virus. A 2- to 4-fold antibody decline took place from early convalescence to 20 months after onset.

Adolescent↗
PubMed1984

Association of a Sindbis-like virus with Ockelbo disease in Sweden.

An alphavirus isolated from Culiseta mosquitoes has been associated with Ockelbo disease, an exanthema arthralgia syndrome occurring in Sweden. The isolate was made from mosquitoes collected in Edsbyn (central Sweden), an area with considerable Ockelbo disease morbidity. This isolate proved to be indistinguishable from Sindbis virus by complement-fixation and hemagglutination-inhibition tests, and was antigenically related to Sindbis in plaque reduction neutralization tests. Patients with Ockelbo disease developed neutralizing antibodies to the virus in their convalescent sera, suggesting that it is the etiologic agent of the disease.

Aedes↗