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Biomedical subjects

B Olsen

Publications and source records attributed to B Olsen.

At least 19 recordsLinked to original sources
PubMed1999

Feral pigeons as carriers of Cryptococcus laurentii, Cryptococcus uniguttulatus and Debaryomyces hansenii.

We collected fresh droppings and cloaca samples from feral pigeons Columba livia in the southern Swedish city of Malmö, and isolated the following fungi: Debaryomyces hansenii var. hansenii, Cryptococcus laurentii and Cryptococcus uniguttulatus. The first two species are known to be pathogenic to humans. No strains of Cryptococcus neoformans var. neoformans were found. Our results indicate that feral pigeons can be carriers of medically significant fungi other than Cryptococcus neoformans var. neoformans.

Animals↗
PubMed1999

Isolation of Lyme disease Borrelia from puffins (Fratercula arctica) and seabird ticks (Ixodes uriae) on the Faeroe Islands.

This is the first report on the isolation of Lyme disease Borrelia from seabirds on the Faeroe Islands and the characteristics of its enzootic cycle. The major components of the Borrelia cycle include the puffin (Fratercula arctica) as the reservoir and Ixodes uriae as the vector. The importance of this cycle and its impact on the spread of human Lyme borreliosis have not yet been established. Borrelia spirochetes isolated from 2 of 102 sampled puffins were compared to the borreliae previously obtained from seabird ticks, I. uriae. The rrf-rrl intergenic spacer and the rrs and the ospC genes were sequenced and a series of phylogenetic trees were constructed. Sequence data and restriction fragment length polymorphism analysis grouped the strains together with Borrelia garinii. In a seroepidemiological survey performed with residents involved in puffin hunting on the Faeroe Islands, 3 of 81 serum samples were found to be positive by two commonly used clinical tests: a flagellin-based enzyme-linked immunosorbent assay (ELISA) and Western blotting. These three positive serum samples also had high optical density values in a whole-cell ELISA. The finding of seropositive Faeroe Islanders who are regularly exposed to I. uriae indicate that there may be a transfer of B. garinii by this tick species to humans.

Animals↗
PubMed1999

Distribution and abundance of the tick Ixodes uriae in a diverse subantarctic seabird community.

At Bird Island, South Georgia, we surveyed the distribution and abundance of ticks on the vertebrate fauna and found only 1 species Ixodes uriae. We classified all seabird species into 3 groups: (1) seabirds nesting on the surface of the ground solitarily, in dispersed groups of a few nests, or in colonies with well-spaced nests; (2) seabirds nesting on the surface of the ground in dense colonies; and (3) seabirds nesting in dense colonies in burrows or rock crevices. We detected I. uriae only on 3 species of the second group that nested in large, dense, persistent colonies, i.e., black-browed albatross (Diomedea melanophrys), gray-headed albatross (Diomedea chrysostoma), and macaroni penguin (Eudyptes chrysolophus). Ticks were found on the undersides of the feet on albatrosses but not on the undersides of the feet on penguins. We hypothesize that the coarse pebble nests of penguins, combined with the fact that their young walk around more than albatross young, make the environment on the underside of penguin feet more harsh and hostile for ticks than the underside of albatross feet. Despite the great abundance of Antarctic fur seals (Arctocephalus gazella) on the island, we found no ticks on them.

Animals↗
PubMed1998

[Jevgenij Botkin--personal physician of the tzar--an obituary 80 years after his death].

On 17 July 1998 the remains of Tsar Nicholas II and his family were buried, a historic event extensively covered by the media. The remains of four servants liquidated with the royal family were buried with them. Among the servants was the Tsar's personal physician, Jevgenij Botkin. Not often does a doctor follow his patients not only onto death, but into death--the Hippocratic oath leading to liquidation, so to speak. Who was Dr. Botkin? Did he know what to expect, or was he just a chance victim?

Famous Persons↗
PubMed1998

[Refugee or immigrant children in hospital].

The aim of the study was to gain knowledge of the diagnosis, length of hospital stay, and ethnic background of refugee and immigrant children admitted to the Paediatric Ward at Aker University Hospital in Oslo, and to find out how well the staff and families of the children communicated. 347 children, admitted from ten districts in the immediate vicinity of the hospital, were included in the study. 133 (38%) children had parents who were both born in a non-western country. 44 of the children came from a refugee background and 89 from an immigrant background. The median stay on the Paediatric Ward was three days for the immigrant children and two days for the refugee children and children from Western countries. None of the groups was admitted more frequently than the others. Refugee and immigrant children were most often admitted because of respiratory diseases or obscure symptoms. Communication between the staff and more than 40% of the families with refugee or immigrant backgrounds was not satisfactory. Three out of four mothers and one out of two fathers were unable to communicate well in Norwegian. One third of the mothers had less than six years of school education and one quarter of the immigrant mothers had never attended school.

Child↗
PubMed1998

PCR detection of Chlamydia psittaci in faecal samples from passerine birds in Sweden.

To investigate to what extent wild passerine birds are carriers of Chlamydia psittaci, 312 faecal samples from 18 bird species were collected. Using the PCR technique and subsequent DNA sequencing, C. psittaci DNA was demonstrated in faecal samples from 9 (2.9%) birds of 6 different species. Sera from 65 bird-ringers, highly exposed to wild birds, were tested by microimmunofluorescence assay for the occurrence of IgG and IgM antibodies to C. psittaci. No such antibodies were found. This results indicate that a significant proportion of wild passerine birds are carriers of C. psittaci, but rarely infectious to humans.

Amino Acid Sequence↗
PubMed1998

Role of the Haemophilus ducreyi Ton system in internalization of heme from hemoglobin.

By cloning into Escherichia coli and construction of isogenic mutants of Haemophilus ducreyi, we showed that the hemoglobin receptor (HgbA) is TonB dependent. An E. coli hemA tonB mutant expressing H. ducreyi hgbA grew on low levels of hemoglobin as a source of heme only when an intact H. ducreyi Ton system plasmid was present. In contrast, growth on heme by the E. coli hemA tonB mutant expressing hgbA was observed only at high concentrations of heme, was TonB independent, and demonstrated that H. ducreyi HgbA was not sufficient to function as a typical TonB-dependent heme receptor in E. coli. Allelic replacement of the wild-type H. ducreyi exbB, exbD, and tonB loci with the exbB, exbD, and tonB deletion resulted in an H. ducreyi isogenic mutant unable to utilize hemoglobin but able to utilize hemin at the same levels as the parent strain to fulfill its heme requirement. This finding confirms the TonB dependence of HgbA-mediated hemoglobin utilization and suggests that uptake of hemin in H. ducreyi is TonB independent. Additionally, the H. ducreyi Ton system mutant synthesized increased amounts of HgbA and other heme-regulated outer membrane proteins, consistent with derepression of these proteins due to lower intracellular heme and/or iron concentrations in the mutant. Sequencing of the Ton system genes revealed that the arrangement of the genes was exbB exbD tonB. The proximity and structure of these genes suggested that they are transcribed as an operon. This arrangement, as well as the DNA and deduced amino acid sequences of these H. ducreyi genes, was most similar to those from other pasteurellae.

Aldehyde Oxidoreductases↗
PubMed1998

Cloning and characterization of tdhA, a locus encoding a TonB-dependent heme receptor from Haemophilus ducreyi.

Haemophilus ducreyi is unable to synthesize heme and must acquire it from its only known host, humans. We cloned and sequenced a gene encoding an outer membrane receptor for heme. It was designated tdhA (for TonB-dependent heme receptor A) since it was related by sequence homology to the family of TonB-dependent receptors. TdhA was strikingly similar to open reading frame HI0113 from the genome of Haemophilus influenzae Rd and also shared homology with five other heme receptors, including HxuC, HemR, HmuR, ChuA, and ShuA, from gram-negative bacteria. An Escherichia coli hemA tonB mutant strongly expressing H. ducreyi tdhA grew on low levels of heme as a source of heme only when an intact H. ducreyi Ton system plasmid was present, formally demonstrating functional TonB dependence. tdhA was expressed poorly in vitro by H. ducreyi and only under conditions of heme limitation. A survey of H. ducreyi revealed that all tested strains but one synthesized small amounts of TdhA in vitro under heme-limiting conditions. Surprisingly, an isogenic mutant of tdhA as well as its parent, 35000, both required the same high levels of heme for growth (50 microgram/ml [77 microM] on agar medium). This result, together with previous findings, suggests that in vitro, the uptake of heme by H. ducreyi is mediated by a TonB- and TdhA-independent mechanism, possibly diffusion.

Amino Acid Sequence↗
PubMed1997

[Murderers in white coats--the physicians' plot against Stalin].

During the Moscow trials in 1936-38 several doctors were sentenced for participating in the murders of party leaders. As others who were accused, the doctors willingly confessed to crimes they could not possibly have committed. A second doctors' plot took place in the autumn of 1952. This time nine doctors, six of them Jews, were arrested for the attempted murder of political leaders. Only the unexpected death of Josef Stalin prevented a new wave of terror. With the single exception of Genrikh Grigorjevitsj Jagoda (1891-1938), head of the NKVD (KGB's predecessor), all those sentenced under the Moscow process are now rehabilitated. The participants of the second doctors' plot were rehabilitated immediately after Stalin's death.

Famous Persons↗
PubMed1997

Leuconostoc spp. septicaemia in a child with short bowel syndrome.

Septicaemia caused by the vancomycin-resistant Gram-positive bacteria Leuconostoc spp. is uncommon. We report a case of Leuconostoc spp. septicaemia in a child with short bowel syndrome fed through a central venous catheter and a gastrostomy. Leuconostoc spp. were isolated from several blood cultures. Despite several courses of antibiotics the fever continued and her condition deteriorated. After removal of the thrombotized central venous catheter her condition improved. Leuconostoc spp. was isolated from the thrombotic masses.

Bacteremia↗
PubMed1997

CD4 lymphopenia in a patient with cryptococcal osteomyelitis.

Cryptococcus neoformans is a rarely reported cause of osteomyelitis. In most cases, no obvious underlying condition is found. Immunological laboratory data, however, are not generally available. In the present case of cryptococcal osteomyelitis, idiopathic CD4 lymphopenia was detected. This immunodeficiency is found in cases of disseminated cryptococcosis by chance. Possibly, it may be one so far unrecognized underlying condition in cryptococcal osteomyelitis.

Aged↗
PubMed1997

Enteropathogenic bacteria in migrating birds arriving in Sweden.

Birds have been thought to play a role in transmitting infectious agents like influenza, Borrelia and Salmonella. To investigate the role of migrating birds in the dispersal of enteropathogenic bacteria, stool samples from 151 wild birds (50 gulls and 101 passerines) just entering Sweden from their winter grounds were analysed for Salmonella spp., Campylobacter spp. and EHEC O157:H7. The thermophilic isolated enteropathogens found were further analysed by antibiograms. Among the 50 gulls examined, we found 2 isolates of Salmonella typhimurium with multiple antibiotic resistance. Three isolates of C. jejuni were found in the 101 stool samples from passerines. We did not isolate EHEC O157:H7 in any of the bird stools examined.

Animals↗
PubMed1997

Inhibition of angiogenesis by tissue inhibitor of metalloproteinase-3.

PURPOSE: It has been established that Sorsby's fundus dystrophy, a dominantly inherited form of blindness, is caused by mutations in the tissue inhibitor of metalloproteinase-3 (TIMP-3) gene. Because choroidal neovascularization is a prominent feature of Sorsby's fundus dystrophy, the authors have examined whether TIMP-3 protein plays a role in the regulation of angiogenesis. METHODS: Chemotaxis of endothelial cells toward vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) was examined using a modified Boyden chamber assay. Endothelial cells placed in the upper chamber were allowed to migrate through a polycarbonate membrane with 8 microns pores toward VEGF or bFGF present in the lower chamber. Next, the ability of TIMP-3 to inhibit chemotaxis was studied by incubating the cells with varying amounts of TIMP-3 during the assay. Finally, an in vitro angiogenesis assay was performed on collagen gels. Endothelial cells were seeded onto three-dimensional collagen gels. Treatment with bFGF and VEGF induced invasion of the gel and the formation of tube-like structures. TIMPs (1, 2, and 3) were added to the cultures to determine their effect on invasion. An in vivo chorioallantoic membrane (CAM) assay was performed using methylcellulose discs containing bFGF with or without TIMP-3. Induction of new blood vessels was observed with a stereomicroscope. RESULTS: TIMP-3 inhibits chemotaxis of vascular endothelial cells toward VEGF and bFGF, inhibits collagen gel invasion and capillary morphogenesis in vitro, and inhibits bFGF-induced angiogenesis in the CAM assay in vivo. CONCLUSIONS: TIMP-3 has the potential to inhibit angiogenesis. These results allow us to speculate on a possible mechanism by which mutant TIMP-3 protein might contribute to the Sorsby fundus dystrophy phenotype.

Allantois↗