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Biomedical subjects

B Jansson

Publications and source records attributed to B Jansson.

174 records · Page 10Linked to original sources
PubMedDate not supplied

A synthetic IgG-binding domain based on staphylococcal protein A.

A synthetic IgG-binding domain based on staphylococcal protein A was designed with the aid of sequence comparisons and computer graphic analysis. A strategy, utilizing non-palindromic restriction sites, was used to overcome the difficulties of introducing site-specific changes into the repetitive gene. A single mutagenized gene fragment was polymerized to different multiplicities, and the different gene products were expressed in Escherichia coli. Using this scheme, protein A-like proteins composed of different numbers of IgG-binding domains were produced. These domains were changed to lack asparagine--glycine dipeptide sequences as well as methionine residues and are thus, in contrast to native protein A, resistant to treatment with hydroxylamine and cyanogen bromide.

Amino Acid Sequence↗
PubMedDate not supplied

Epitopes on CA 125 from cervical mucus and ascites fluid and characterization of six new antibodies. Third report from the ISOBM TD-1 workshop.

CA 125 is found in body fluids in a variety of molecular weight forms. The largest species are found in normal abdominal fluid and cervical mucus. The present study therefore incorporated CA 125 derived from these sources as well as ascites fluid to investigate if the source of CA 125 influenced epitope characterization. Ascites-derived CA 125 varied in size from about 190 to about 2,700 kD. Cervical mucus-derived CA 125 treated with ultrasound changed its apparent size from more than 20,000 to 700 kD. Epitope mapping of antibodies was not grossly influenced by the size or source of CA 125 used as target. However, low-molecular-weight CA 125, i.e. ascites fractions CA 17/E, CA 17/F and CA 10/7, did show differences in certain assay combinations and cross-inhibition patterns which probably can be explained by steric effects due to the smaller size compared with the most abundant forms of CA 125 present in serum and other body fluids. The specificity of six new monoclonal antibodies to CA 125 was tested by cross-inhibition and immunometric assay combinations and compared to reference antibodies. One antibody, X306, belonged to the OC125-like antibodies. Four antibodies, X52, X75, X325 and VK8, were M11-like. The sixth antibody, 7C12, reacted with an epitope which was difficult to define. This antibody was inhibited by M11-like antibodies and OV197. However, used as an inhibitor, 7C12 inhibited only itself. We grouped it as an OV197-like antibody, but clearly different from OV197. The topography of epitopes was studied by analyzing all antibody pairs in immunoradiometric assays. These results confirmed the grouping of antibodies described above and are in accordance with previous findings that the highest signal is obtained using an OC125-like antibody or OV197 on the solid phase and an M11-like antibody as tracer. The composition of the sample in terms of high- and low-molecular-weight species of CA 125 was measured, with different responses depending on the antibody pair used. This might be one reason for discrepancies between assay results for CA 125 using different assays.

Antibodies, Monoclonal↗
PubMedDate not supplied

Correlations between serum osmolality and endolymphatic sac response using hypertonic glycerol.

This study, using mice, correlated serum osmotic pressure, experimentally elevated with an intravenous injection of glycerol of varying tonicity (1.3, 2.6 and 5.2 g glycerol/kg body weight) with endolymphatic sac (ES) response. The injection produced a rise in serum osmotic pressure that was measured after 15 min (from 308 +/- 12.9 mosm/kg b.w. to 320 +/- 1.9, 353 +/- 19.3, 427 +/- 9.4 mosm/kg b.w., respectively). Normal levels were noted about 60 min after the injection. The ES was graphically displayed at 0 min, 1, 2 and 4 h using as a basis composite electron micrographs. The ES responded with signs of active secretion and degradation of macromolecular substances which appeared to be related to the rise in serum osmotic pressure. The study showed that the ES responds to glycerol injection with fine structural changes indicative of increased intra-epithelial synthesis of sugar/protein residues which are secreted and degraded within its lumen. The technique used made it possible to characterize the ultrastructural secretory pathways from the epithelial cells into the sac lumen. The results indicate that the ES may sense and respond to dynamic changes of the micro-osmotic environment probably via alterations in inner ear fluid homeostasis.

Animals↗
PubMedDate not supplied

CA 125--epitopes and molecular size.

CA 125 has two main immunogenic areas reactive with mouse and rat monoclonal antibodies. These areas are defined by the antibodies OC 125 and M11, respectively. Antibodies related to the main groups are named OC 125-like and M 11-like antibodies. The OC 125-like antibodies can be subgrouped into four sets, whereas the M 11-like antibodies segregate into many closely related binding specificities. One M 11-like antibody, ZR38, is not fully inhibited by any other M 11-like antibody and therefore represents a distinct subgroup. A single antibody, OV 197, is related to some OC 125-like antibodies, but not to OC 125. However, OC 125 enhances binding of OV 197 to its epitope. A new antibody, 7C 12, induces conformation changes, affecting binding of some M 11-like and some OC 125-like antibodies. CA 125 exists as very large molecules that can be partly disrupted by SDS and heat. The form found in serum might be a degradation product from a larger molecule found in the abdominal and other serous cavities.

Animals↗
PubMedDate not supplied

The autogenous mucosal cyst. An experimental study with special reference to reconstructive surgery of the airway.

Autogenous buccal mucosa was transplanted to the pretracheal region in beagles. The result was studied by surgical exploration, light microscopy, transmission electron microscopy and scanning electron microscopy. The grafts were transformed into mucosal cysts after 4 weeks. There was no significant alteration of the epithelium of the cyst wall proper as compared with normal mucosa. After observation periods of 4 to 13 weeks a cyst adequate for further transplantation procedures had developed. There were no essential differences between cysts observed at four weeks and those observed at later periods up to 13 weeks. The possibilities of combining the mucosa with framework materials (bone, cartilage, alloplastic materials, etc) and flaps (e.g. deltopectoral & myocutaneous) are mentioned.

Animals↗
PubMedDate not supplied

Experimental reconstruction of the airway with buccal mucosa and cortical bone in a single-stage procedure.

Autogenous buccal mucosa and cortical bone were transplanted in a one-stage procedure to an anterior tracheal defect in 5 beagles. The result was studied by endoscopy, light microscopy, scanning electron microscopy and transmission electron microscopy. The bone graft was shaped as an oval disc and perforated with large holes for vascular nutrition of the mucosal graft. Small holes were made along the periphery for suturing the buccal mucosa to the bone disc and for suturing the composite graft to the tracheal defect. The mucosa sloughed off from the framework during the first 2 weeks and the bone graft was subsequently expelled through the airway. The mucosal graft was replaced by ciliated columnar epithelium supported by firm connective tissue. Various surface structures were found in the regenerating epithelium. Although the animals did not suffocate or develop a stenosis, this procedure cannot in its present form be recommended for use in clinical practice.

Animals↗
PubMedDate not supplied

Reconstruction of the airway with a composite alloplastic and autogenous graft. An experimental study.

A method by which an alloplast can be lined with mucosa and thereafter used as a composite pedicled graft is described and discussed. Autogenous buccal mucosa was transplanted to the pretracheal region in five beagles. Subsequently a cyst developed in which the graft constituted the main part of the cyst wall. After 5 to 6 weeks the cyst was explored and a Proplast sheet was sutured to its exterior. After another 3-9 weeks the area was explored again. A composite graft had then formed comprising buccal mucosa on the outside, stabilized by Proplast and supplied by blood vessels arising from the strap muscles and their fascia. After opening of the cyst, the composite graft was used to repair a tracheal defect in the same dog. All of the dogs survived and they did not lose any weight. The graft areas were removed 5 1/2-9 months after the tracheal window repair. Tracheoscopy was performed at least twice on each dog. The grafted areas were also studied by light microscopy, scanning electron microscopy and transmission electron microscopy. The grafts survived in all cases. There was no tendency towards graft extrusion. Connective tissue cells predominated in the pores of the Proplast framework, in which small foci of metaplastic bone formation were also seen.

Animals↗
PubMedDate not supplied

The autogenous mucosal cyst procedure. Experimental reconstructive surgery of the airway with a new composite graft technique.

Autogenous buccal mucosa was transplanted to the pretracheal region in five beagles. Subsequently a cyst developed in which the graft constituted the main part of the cyst wall. After 4 to 13 weeks the cyst was explored and a perforated autogenous cortical bone plate was sutured to its vertex. After a further 5 to 7 weeks the resulting composite graft was sutured to an anterior tracheal window defect. All dogs survived. They did not lose weight. One dog had moderate breathing difficulties during exertion. At bronchoscopy, which was performed in all dogs, no contractions or granulations were seen but the stability of the airway wall in the grafted areas was reduced. These areas were removed after 8 to 15 months and studied by light microscopy, scanning electron microscopy and transmission electron microscopy. The mucosa survived in all cases. Total resorption of the bone graft occurred in all but two cases, in which remnants were found.

Animals↗
PubMedDate not supplied

Cochlear blood flow in noise-damaged ears.

Cochlear blood flow was measured in rats with a known noise-induced hearing loss, using the microsphere technique. The animals were exposed to simulated industrial noise for 3 months. The rats were divided into four groups: young and old; normotensive (N) and spontaneously hypertensive (SH). The mean values of the cochlear blood flows were compared with those of rats from matched groups not exposed to noise. The mean cochlear blood flow in the noise-exposed groups was lower than in the non-exposed groups. The decrease in cochlear blood flow was significant for all groups except young SH rats and was more pronounced in the older age group. Cochleas from the groups of old N and SH rats were investigated in the scanning electron microscope. Extensive changes were far more common in SH than in N rats.

Animals↗
PubMedDate not supplied

Cochlear blood flow in endolymphatic hydrops.

There is no animal model for Meniere's disease but by obliteration of the endolymphatic duct, endolymphatic hydrops may be achieved in several animal species. In order to measure the cochlear blood flow in ears with endolymphatic hydrops the endolymphatic duct was obliterated in 9 guinea pigs. The blood flow was measured with the microsphere method and the cochlear histology was studied. The regional and total blood flow was determined in the serially sectioned cochleas 2, 4 and 8 months after obliteration of the endolymphatic duct. No change in regional or total cochlear blood flow was observed in the hydropic ears.

Animals↗
PubMedDate not supplied

Monitoring and risk assessment by means of alkyl groups in hemoglobin in persons occupationally exposed to ethylene oxide.

In persons occupationally exposed to ethylene oxide, i.e. under the conditions described by Dunkelberg and Hartmetz (1977), the degree of alkylation in histidine of hemoglobin was determined. Quantitative determination of N-3-(2-hydroxyethyl)histidine by mass fragmentography and by ion-exchange amino-acid analysis gave consistent results. Data are in agreement with the fast elimination from tissues (lambda = 4.6 hr-1, i.e. biological half-life about 9 min) found in the mouse. At the respiration rate of light work, and exposure dose of 1 ppm/hr results in a tissue dose that is estimated to involve a risk amounting to 1.101 mrad-equivalents of stochastic effects with a genetic mechanism.

Adult↗