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Biomedical subjects

M Lindberg

Publications and source records attributed to M Lindberg.

At least 145 records · Page 8Linked to original sources
PubMed1988

Chimeric IgG-binding receptors engineered from staphylococcal protein A and streptococcal protein G.

Chimeric Fc receptors, consisting of the IgG-binding domains of both staphylococcal protein A and streptococcal protein G, were constructed. An efficient bacterial expression system was used to produce the recombinant proteins, which vary in size and number of IgG-binding domains. The purified receptors were analyzed by immunodiffusion and a competitive enzyme-linked immunosorbent assay to establish the relative binding strength to various polyclonal and monoclonal immunoglobulins from different species. The results demonstrate that protein A and protein G have complementary binding patterns and that the chimeric receptors retain the binding capacities of both the parental constituents. This suggests that these novel chimeric receptors might be versatile reagents for immunochemical assays.

Animals↗
PubMed1987

Structure and evolution of the repetitive gene encoding streptococcal protein G.

The complete sequence of the structural gene encoding the immunoglobulin G binding protein from Streptococcus G148 has been determined, as well as its 5' and 3' flanking sequences. The sequence reveals an open reading frame encoding a putative preprotein with a relative molecular mass of 63294. N-Terminal sequencing of the mature protein, spontaneously released from streptococcal cells, demonstrates that the signal peptide consists of 33 amino acids. The DNA sequence reveals extensive internal homologies similar to other cell-wall-bound receptors from gram-positive bacteria. Comparisons with a related gene previously isolated from another strain of streptococci revealed large differences in size, due to variations in the number of internal repeats. The structure of the gene suggests an evolution through multiple duplications.

Amino Acid Sequence↗
PubMed1987

Cloning and expression of the gene for a fibronectin-binding protein from Staphylococcus aureus.

The gene encoding the fibronectin-binding protein (FNBP) from Staphylococcus aureus strain 8325-4 was isolated from a gene bank in pBR322. The original clone, containing a 6.5-kb insert, gave a functional product present in the periplasm of Escherichia coli. Analysis of polypeptides isolated after affinity chromatography on fibronectin-Sepharose followed by ion-exchange chromatography revealed two gene products, 87 and 165 kd in mol. wt. The amino acid compositions of these two polypeptides and a native FNBP from S. aureus strain Newman were very similar. Antibodies raised against the native FNBP from strain Newman precipitated the 125I-labelled 165-kd polypeptide, and unlabeled 165- and 87-kd polypeptides as well as native FNBP inhibited the immunoprecipitation reactions. The region of the fnbp-gene encoding the fibronectin-binding activity has been identified and subcloned in an expression vector based on the staphylococcal protein A gene. The resulting product in E. coli is an extracellular fusion protein consisting of two IgG-binding domains of protein A followed by a fibronectin-binding region. The fusion protein binds to fibronectin and completely inhibits the binding of fibronectin to intact cells of S. aureus.

Cloning, Molecular↗
PubMed1987

Co-existence of abdominal aortic aneurysms and intracranial aneurysms.

The occurrence of abdominal aortic aneurysms (AAAs) and intracranial aneurysms (IAs) in the same patient and in the same family was studied among 89 patients with AAAs and 485 patients with IAs. Among the AAA-patients two had IAs themselves and five had IAs in the family, whereas three IA-patients had AAAs themselves and eight had AAAs in the family. Moreover, one of the patients with both AAA and IA had a blood relative with AAA, and in six of the families with both types of aneurysms there were more than two subjects with aneurysms. The results indicate, that AAAs and IAs may have a common aetiologic factor.

Adult↗
PubMed1987

Elemental changes in guinea-pig epidermis in the hyperplastic response to irritant stimuli.

A mild irritant reaction was induced by application of sodium lauryl sulphate to the skin of guinea-pigs. The response was analysed at 24 and 48 h after application using light microscopy, transmission electron microscopy and energy dispersive X-ray microanalysis (EDX). It was found that the sodium lauryl sulphate induced a hyperplastic response in the epidermis with an increased number of keratinocytes. This response was associated with significantly increased levels of intracellular sodium and chloride. The elemental changes were most marked at 24 h, whereas the number of keratinocytes was highest at 48 h. The pattern of the elemental changes and the ultrastructural alterations are compatible with initial membrane damage followed by a transient increase in proliferative activity. The present results demonstrate that EDX is a useful tool for the analysis of functional alterations in epidermal keratinocytes under pathological conditions.

Animals↗
PubMed1987

Intracranial aneurysms and heredity.

The occurrence of intracranial aneurysms (IAs) in the families of 579 consecutive patients with subarachnoid hemorrhage (SAH), of whom 485 had verified IAs, was studied retrospectively. IAs occurred in the families of 6.7% of the IA patients, but only 0.4% of their siblings had IAs. However, there were differences between the familial and nonfamilial IA patients, indicating that the familial patients are a specific small subpopulation of IA patients. The familial patients were younger, often had multiple aneurysms, and had aneurysms frequently located on arteries other than those in the nonfamilial group.

Adult↗
PubMed1987

The effect of grenz rays on irritant skin reactions in man.

To investigate the effect of grenz rays on irritant contact reactions, eleven healthy volunteers were studied. They were given 3 Gy of grenz rays, once a week for 3 weeks, to a defined area of the back. Twenty-four hours after the last treatment, serial dilution sodium lauryl sulphate patch tests were applied both on the grenz ray treated area and on the untreated control skin. Biopsy specimens were taken from the irritant reactions both from the grenz ray treated area and from the control area and different cell populations in dermis and epidermis were identified by monoclonal antibodies (Leu 2, 3, 4, 7, Leu M1, B1, OKT6). In the grenz ray treated epidermis there was a pronounced reduction of OKT6-positive cells but the composition of the dermal cellular infiltrate did not differ between control and grenz ray treated skin. The assessment of the patch test reactions did reveal a tendency towards weaker reactions in the grenz ray pre-treated skin but this difference was not statistically significant. It is concluded that grenz rays do not have a marked effect on the elicitation of irritant reactions.

Adult↗
PubMed1987

Membrane-coating granules in "dry" non-eczematous skin of patients with atopic dermatitis. A quantitative electron microscopic study.

In recent years much interest has been focused on the functions of the membrane-coating granules (MCGs). These granules seem to play an essential role in the formation of the barrier of the stratum corneum by extruding their lipid-rich content into the extracellular space of the corneocytes. The dry non-eczematous skin in atopic dermatitis has been reported to have defective barrier function. In the present study a quantitative electron microscopic analysis was made of the volume of MCGs in the transition zone between the stratum granulosum and stratum corneum in dry skin of patients with atopic dermatitis. The relative volume of MCGs was significantly greater than that in normal skin. This finding may indicate a disturbance of the "maturation" of the MCGs, leading to a defect in the barrier function in atopic dermatitis.

Adult↗
PubMed1987

Human epidermal Langerhans' cells in bullous pemphigoid.

Through the epidermal analysis of 13 patients with bullous pemphigoid compared to controls, using OKT6 monoclonal antibodies on the light microscopic level and electron-microscopy, we found a redistribution of the Langerhans' cells towards the basal membrane in combination with an increased total number of Langerhans' cells. This redistribution was also noted in clinically normal skin from patients with bullous pemphigoid. The findings may be consistent with the theory of antigen presentation.

Aged↗