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Biomedical subjects

Y Ostberg

Publications and source records attributed to Y Ostberg.

At least 19 recordsLinked to original sources
PubMed2001

P13, an integral membrane protein of Borrelia burgdorferi, is C-terminally processed and contains surface-exposed domains.

To elucidate antigens present on the bacterial surface of Borrelia burgdorferi sensu lato that may be involved in pathogenesis, we characterized a protein, P13, with an apparent molecular mass of 13 kDa. The protein was immunogenic and was expressed in large amounts during in vitro cultivation compared to other known antigens. An immunofluorescence assay, immunoelectron microscopy, and protease sensitivity assays indicated that P13 is surface exposed. The deduced sequence of the P13 peptide revealed a possible signal peptidase type I cleavage site, and computer analysis predicted that P13 is an integral membrane protein with three transmembrane-spanning domains. Mass spectrometry, in vitro translation, and N- and C-terminal amino acid sequencing analyses indicated that P13 was posttranslationally processed at both ends and modified by an unknown mechanism. Furthermore, p13 belongs to a gene family with five additional members in B. burgdorferi sensu stricto. The p13 gene is located on the linear chromosome of the bacterium, in contrast to five paralogous genes, which are located on extrachromosomal plasmids. The size of the p13 transcript was consistent with a monocistronic transcript. This new gene family may be involved in functions that are specific for this spirochete and its pathogenesis.

Amino Acid Sequence↗
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

Efficiency of automotive cabin air filters to reduce acute health effects of diesel exhaust in human subjects.

OBJECTIVES: To evaluate the efficiency of different automotive cabin air filters to prevent penetration of components of diesel exhaust and thereby reduce biomedical effects in human subjects. Filtered air and unfiltered diluted diesel exhaust (DDE) were used as negative and positive controls, respectively, and were compared with exposure to DDE filtered with four different filter systems. METHODS: 32 Healthy non-smoking subjects (age 21-53) participated in the study. Each subject was exposed six times for 1 hour in a specially designed exposure chamber: once to air, once to unfiltered DDE, and once to DDE filtered with the four different cabin air filters. Particle concentrations during exposure to unfiltered DDE were kept at 300 micrograms/m3. Two of the filters were particle filters. The other two were particle filters combined with active charcoal filters that might reduce certain gaseous components. Subjective symptoms were recorded and nasal airway lavage (NAL), acoustic rhinometry, and lung function measurements were performed. RESULTS: The two particle filters decreased the concentrations of diesel exhaust particles by about half, but did not reduce the intensity of symptoms induced by exhaust. The combination of active charcoal filters and a particle filter significantly reduced the symptoms and discomfort caused by the diesel exhaust. The most noticable differences in efficacy between the filters were found in the reduction of detection of an unpleasant smell from the diesel exhaust. In this respect even the two charcoal filter combinations differed significantly. The efficacy to reduce symptoms may depend on the abilities of the filters investigated to reduce certain hydrocarbons. No acute effects on NAL, rhinometry, and lung function variables were found. CONCLUSIONS: This study has shown that the use of active charcoal filters, and a particle filter, clearly reduced the intensity of symptoms induced by diesel exhaust. Complementary studies on vehicle cabin air filters may result in further diminishing the biomedical effects of diesel exhaust in subjects exposed in traffic and workplaces.

Acute Disease↗
PubMed1996

Surface exposure and species specificity of an immunoreactive domain of a 66-kilodalton outer membrane protein (P66) of the Borrelia spp. that cause Lyme disease.

A chromosomally encoded 66-kDa protein (P66) of Borrelia spp. that cause Lyme disease has previously been shown to be associated with the spirochetal outer membrane. A topological model of P66 predicts a surface-exposed fragment which links the N- and C-terminal intramembranous domains of the protein (J. Bunikis, L. Noppa, and S. Bergström, FEMS Microbiol. Lett. 131:139-145, 1995). In the present study, an immunogenic determinant of P66 was identified by a comparison of the immunoreactivities of different fragments of P66 generated either by proteolytic treatment of intact spirochetes or as recombinant proteins expressed in Escherichia coli. The immune response to P66 during natural infection was found to be directed against the predicted surface domain which comprises amino acids at positions 454 through 491. A sequence comparison revealed considerable polymorphism of the surface domains of P66 proteins of different Lyme disease-causing Borrelia species. Five sequence patterns of this domain were observed in the B. garinii strains studied. In contrast, sequences of the relevant part of P66 of the B. afzelii and B. burgdorferi sensu stricto isolates studied were identical within the respective species. In immunoblotting, 5 of 17 (29.4%) sera from North American patients with early disseminated or persistent Lyme disease reacted against P66 of B. burgdorferi sensu stricto B31. These sera, however, failed to recognize P66 of B. afzelii and B. garinii, as well as an analog of P66 in the relapsing fever agent, B. hermsii. In conclusion, the topological model of P66 is supported by the demonstration of an apparent surface localization of an immunoreactive domain of this protein. Furthermore, analogous to the plasmid-encoded borrelial outer surface proteins, the predicted surface-exposed portion of chromosomally encoded P66 appears to be antigenically heterogenous.

Amino Acid Sequence↗
PubMed1993

Echocardiographic findings in patients with primary Sjögren's syndrome.

Cardiac involvement in 27 consecutive patients fulfilling the criteria for primary Sjögren's syndrome was evaluated using echo-doppler-cardiography. A clinical physical examination showed that the heart was normal in all patients. Nine (33%) had signs of present or previous pericarditis with effusion and/or fibrin deposition, four of them had chest symptoms. The pericarditis patients were slightly older, had significantly shorter disease duration, had significantly increased levels of orosomucoid and haptoglobin, and were significantly more often antinuclear-antibody positive than those without pericarditis. Of the echocardiographic measurements, the left ventricular systolic dimension was significantly smaller and the fractional shortening of the left ventricle significantly higher in the pericarditis patients. However, four of the nine pericarditis patients had localized hypokinesia of the left ventricle, all with unspecific ECG changes, while only one without pericarditis showed this symptom. No patient had low voltage, ST-T elevation or conduction abnormalities. Mitral valvular thickening was found in one patient and age-related sclerosis of the aortic cusps appeared in some.

Adult↗
PubMed1991

Features of Sjögren's syndrome in patients with primary biliary cirrhosis.

Twenty-six consecutive patients with primary biliary cirrhosis (PBC) from northern Sweden were studied regarding the occurrence and features of Sjögren's syndrome (SS). In more than 50% of the patients the rose bengal dye test showed conjunctival and/or corneal staining. In six patients keratoconjunctivitis sicca (KCS) was present with positive rose bengal and Schirmer tests. In a further three patients only the results of the Schirmer tests were abnormal. Radiological findings of sialectasia were demonstrated in six patients, five of whom had KCS. Two of the seven patients who fulfilled our criteria for Sjögren's syndrome were HLA-B8 positive. A high prevalence of increased immune globulins and rheumatic factor was found, but this did not correlate with the presence of Sjögren's syndrome. Some features of Sjögren's syndrome were found in 73% of PBC patients, and keratoconjunctivitis sicca and/or sialectasia were found in 27% of PBC patients. This constitutes a high frequency of secondary manifestations of the liver disease.

Adult↗
PubMed1988

Immunohistochemical analyses of autoimmune sialadenitis in man.

The immunoreactivity pattern for different monoclonal antibodies to cytokeratins and to vimentin in epimyoepithelial islands typical for glands of patients with Sjögren's syndrome has been compared with that of normal parotid gland tissue. Two types of epithelial island cells were observed: one had an intermediate filament protein pattern similar to that of ordinary duct epithelial cells of normal parotid gland. The other had an intermediate filament protein pattern typical of myoepithelial and/or basal duct cells in normal glands. Thus, we conclude that the islands are composed of a mixed population of gland cells on the basis of their content of cytokeratins or of cytokeratins and vimentin. These cells might originate from pluripotential reserve cells or from ordinary duct, myoepithelial and/or basal duct cells which may have undergone metaplasia.

Antibodies, Monoclonal↗
PubMed1984

Distribution of intermediate filaments and actin microfilaments in parotid autoimmune sialoadenitis of Sjögren syndrome.

In order to study the importance of myoepithelial cells in the formation of parotid epi-myoepithelial islands of the autoimmune sialoadenitis in Sjögren's syndrome, the distribution of cytoskeletal elements has been investigated by electron and immunofluorescence microscopy. Antibodies to intermediate filament proteins--prekeratins, desmin and vimentin--were used as well as a 'DNase I/anti-DNase I' immunohistochemical procedure to detect actin microfilaments for characterization of myoepithelial cells compared to the other types of parotid epithelial cells. Two types of prekeratin antibodies were raised. One of these reacted preferentially with myoepithelial cells. The same type of antiserum also showed a bright fluorescence in cells located peripherally in the epi-myoepithelial islands. These island cells, however, exhibited only a very low actin microfilament content and were thus not ordinary myoepithelial cells. The other type of prekeratin antibodies reacted with all types of parotid epithelia, except acinar secretory epithelium. They also stained all island epithelial cells, but the reactivity was less in cell regions with pronounced lymphocyte infiltration. The heterogeneity between the island epithelial cells, immunohistochemically as well as ultrastructurally, indicates different stages of island formation. Interepithelial lymphocytes showed less vimentin and actin filament content in comparison with lymphoid cells outside the islands. Conclusively, typical epi-myoepithelial islands are composed of metaplastic epithelial cells of intercalated duct origin and invaded lymphoid cells, and ordinary myoepithelial cells are lacking.

Actins↗
PubMed1983

The clinical picture of benign lympho-epithelial lesion.

The histopathological diagnosis 'benign lympho-epithelial lesion' characterizes the major salivary gland disease in Sjögren's syndrome. It is not known if all cases with microscopically diagnosed benign lympho-epithelial lesion are variants of Sjögren's syndrome. The present clinical investigation showed that in 19 patients with the microscopical diagnosis of lympho-epithelial lesion, 84% fulfilled all criteria of Sjögren's syndrome. The rheumatoid factor and/or antinuclear factor was found in 84% and M-component was present in 16%. Sialography revealed sialectasis in all parotid glands. Salivary gland enlargement was found in 79%, and keratoconjunctivitis sicca in 89% of the patients. Systemic disease was found in 32%. The disease in the 2 patients with M-component took a malignant course, culminating in immunoblastic sarcoma and myelomatosis. The clinical diagnosis 'autoimmune sialadenitis' is proposed for the oral and salivary gland component is Sjögren's syndrome.

Adult↗
PubMed1979

The autoimmune submandibular sialoadenitis of the NZB/NZW hybrid mice. A light and electron microscopical investigation.

An electron microscopic study of the submandibular salivary gland lesion occurring in the NZB/NZW F1 hybrid mice was performed, and the findings were discussed and correlated to the autoimmune salivary gland disease observed in patients with Sjögren's syndrome. Within the submandibular salivary gland of this mouse strain focal infiltrates of mononuclear inflammatory cells were observed. Lymphoid cells were observed inside the basal lamina of acini and ducts, leading to destruction of these glandular units. The typical duct cell proliferation found in the autoimmune sialoadenitis of Sjögren's syndrome with the formation of the typical epimyoepithelial islands was not found in the submandibular glands of NZB/NZW mice.

Animals↗
PubMed1979

Laryngeal chondrosarcoma in Sweden.

Between 1958 and 1972, 5 cases of posterior cricoid chondrosarcoma were reported to the Swedish Cancer Registry. These cases, and one recently observed case of laryngeal chondrosarcoma, are presented in this study of one female and five male patients. The tumours grow slowly and recur locally, but have not metastasized, and none of the patients has died from tumour disease. The clinical and morphological findings indicate that these tumours represent secondary chondrosarcomas developing from pre-existing benign ecchondromas. The reason for the uniformity as to localization is not known. The microscopic appearance varied in different parts of the same tumour. The presently obtained data and review of the literature indicate that laryngeal chondrosarcomas are extremely rare, locally invasive, but usually not metastasizing tumours. Conservative laryngeal operation is suggested as primary treatment. Total laryngectomy is necessary only after local recurrences involving a major portion of the cricoid cartilage.

Aged↗
PubMed1976

On the occurrence of argyrophil cells in salivary glands.

Salivary glands (parotid, submandibular and sublingual glands) of nine mammalian species were investigated with respect to presence and localization of argyrophil and argentaffin cells. With the exception of the parotid gland of the rat, no positive staining was observed within the examined glands. In the rat parotid distinctly argyrophil cells could be demonstrated in the intercalated ducts. Histochemical studies of the cells, ultrastructural analysis of their cytoplasmic granules as well as their reactions to certain drugs indicate that these cells are of exocrine rather than of endocrine nature. After a subcutaneous injection of pilocarpine, the intensity of the argyrophil staining was markedly reduced. No specific catecholamine fluorescence could be detected within the cells, not even after pretreatment of the animals with high doses of L-DOPA. The membrane-bounded cytoplasmic granules of the intercalated duct cells furthermore displayed a strong positive staining reaction after treatment of ultrathin Vestopal sections with the periodic acid-chromic acid-silver technique of Rambourg et al. (1969).

Animals↗