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Biomedical subjects

M Lindberg

Publications and source records attributed to M Lindberg.

At least 91 records · Page 5Linked to original sources
PubMed1995

The presence of body hair influences the measurement of skin hydration with the Corneometer.

Techniques for the assessment of skin hydration are often based on the electrical properties of the stratum corneum. A commonly used instrument for measurements of skin moisture is the corneometer, which detects changes in the dielectric constant of the material in contact with the probe. It has been suggested that different materials, for example cream residues and desquamating scales, may interfere with the Corneometer readings, but this question has not been settled conclusively in previous studies. In the present study the influence of body hair was examined. Significantly lower Corneometer values were obtained on the dorsal aspect of the forearm than on the volar aspect (p < 0.05), indicating that the former region was less hydrated than the latter. After shaving of the skin, however, there was no difference in the Corneometer readings between the two regions. Thus, the presence of hair needs to be considered when the hydration status of the skin is examined with the use of a Corneometer.

Adult↗
PubMed1995

Human skin physiology studied by particle probe microanalysis.

Particle probe methods (electron probe and proton probe X-ray microanalysis) have been applied to investigate the distribution of elements and water over the different layers of the epidermis. For major elements, electron probe X-ray microanalysis (XRMA) provides the advantage of superior spatial resolution, but for trace element analysis the more sensitive proton probe (particle induced X-ray emission, PIXE) analysis has to be used. On a dry weight basis, the concentration of S is rather constant across the epidermis, whereas the concentrations of P, K, Cl and Na show gradients with high levels in stratum germinativum (basale) and stratum spinosum but low levels in the stratum granulosum and stratum corneum. Essentially, Fe and Zn are confined to the basal region in normal skin. The concentration of Ca, however, increased steadily from the basal region to the stratum corneum. The probe technique allows quantitative analysis of stratum-specific changes in elemental content in a variety of pathological conditions, e.g., changes induced by nickel, detergents and other chemicals, or in psoriatic skin. Of particular interest are findings of increased Fe and Zn in non-involved psoriatic skin. Since the different layers of the skin have different elemental concentrations and react differently under pathological conditions, the probe techniques are far superior to bulk chemical analysis in elucidating physiological and pathological processes in the skin.

Apoptosis↗
PubMed1994

A fibronectin-binding protein from Streptococcus equisimilis: characterization of the gene and identification of the binding domain.

We have cloned and characterized a gene, fnb, from S. equisimilis, encoding a fibronectin-binding protein, FnB. A genomic library containing chromosomal DNA from S. equisimilis strain Se165 in the pUC18 vector in E. coli TG1 was screened using a DNA fragment of the gene fnbB from S. dysgalactiae strain S2 as probe. The complete gene was sequenced. The molecular mass of the protein, calculated from the deduced amino acid sequence is 120 kDa, which coincides with that determined by gel electrophoresis and Western blotting of the gene product. The fibronectin-binding activity was localized to a region of three repeated units, each 36 amino acids long. The COOH-terminal part of FnB from S. equisimilis, including the repeated Fn-binding domain, is very similar to the corresponding part of FnBB from S. dysgalactiae, indicating a common origin of the regions encoding Fn-binding activity of the respective genes.

Adhesins, Bacterial↗
PubMed1994

Vaccination against Staphylococcus aureus mastitis: immunological response of mice vaccinated with fibronectin-binding protein (FnBP-A) to challenge with S. aureus.

Mice were immunized with fusion proteins encompassing the fibronectin-binding domain of a staphylococcal fibronectin-binding protein (FnBP-A). A specific antibody response against the fibronectin-binding part of the fusion proteins was detected in the serum of all vaccinated animals. The protective potential of these vaccinations was evaluated in a mouse mastitis model, using Staphylococcus aureus, strain SA113, for challenge. The mice vaccinated with FnBP fusion proteins showed a decreased number of bacteria recovered from the mammary glands and significantly reduced cases of severe mastitis. Histopathological examination of tissue from challenged glands of vaccinated mice revealed either no pathological reactions or disseminated inflammatory reactions with focal necrosis whereas four of six examined tissues from challenged glands of non-vaccinated animals showed total necrosis. A combination of FnBP fusion protein with staphylococcal alpha-toxoid did not increase the efficacy of the vaccination and animals vaccinated with alpha-toxoid alone were as sensitive to challenge as those from the non-vaccinated control group. Thus vaccination of mice with recombinant FnBP resulted in significant protection against challenge with S. aureus.

Adhesins, Bacterial↗
PubMed1994

Quantitative and 3-dimensional analysis of Langerhans cells in basal cell carcinoma. A comparative study using light microscopy and confocal laser scanning microscopy.

We have analysed Langerhans cells (LCs) in basal cell carcinoma (BCC) and in healthy skin in 15 patients, using three different techniques: light microscopic examination of horizontal sheets, and of 6-micron-thick vertical skin sections, and confocal laser scanning microscopy (CLSM) of 25-micron-thick vertical sections. The use of CLSM enables both a quantitative and a three-dimensional (3-D) analysis of the cells in the same tissue volume. A statistically significant reduction in the relative volume of epidermal CD1a reactivity confined to tumour areas was found with CLSM. This difference was confirmed when the number of LCs in horizontal sheets were counted. In contrast, no significant reduction in epidermal CD1a+ cells was found in thin vertical sections. This is probably due to the smaller tissue sample examined, and to variations in the number of CD1a+ cells, with less cells directly overlying the tumour nests. The ratio of CD1a-expressing cells in the epidermis/dermis was significantly reduced in BCCs, compared with healthy looking skin. Few LCs were observed in tumour nests, but they were numerous in the surrounding stroma of the dermis. Three-dimensional reconstructions of CD1a+ cells in BCC revealed striking morphological changes; they had a reduced number of dendrites, and these were often short and had few branches. The results demonstrate that CLSM is a suitable technique for quantitative and morphological analysis of CD1a-expressing cells in the skin. We suggest that the alterations in LC numbers, distribution and morphology in BCC most probably are secondary to changes in the local environment.

Adult↗
PubMed1994

Subarachnoid blood on CT and memory dysfunctions in aneurysmal subarachnoid hemorrhage.

Ninety patients with a previous subarachnoid haemorrhage (SAH) were given a set of memory tests comprising immediate free recall of words (indexing long-term memory, LTM, and short-term memory, STM), final free recall of words (indexing LTM), final cued recall of words (indexing LTM), and a digit span test (indexing working memory, WM). Patients with a large amount of blood on CT, carried out within 72 h of the bleed, showed LTM as well as STM dysfunction, whereas patients with a small amount of subarachnoid blood evidenced only STM dysfunction. Patients with the ruptured aneurysm located on the anterior cerebral artery, however, constituted an exception with dysfunction of both LTM and STM together with intact WM, independent of the amount of subarachnoid blood. Also, patients with internal carotid artery or middle cerebral artery aneurysms and large volume SAH displayed LTM dysfunction, but differed concerning STM, the former showing intact STM and the latter showing STM dysfunction. Thus, it appears, that the combined information from factors such as the amount of subarachnoid blood and the location of the ruptured aneurysm is of vital importance for explaining the different patterns of memory dysfunctions after SAH.

Adult↗
PubMed1993

Fibronectin receptors from Streptococcus dysgalactiae and Staphylococcus aureus. Involvement of conserved residues in ligand binding.

The nucleotide sequence of two genes encoding fibronectin (Fn) receptors FnBA and FnBB of Streptococcus dysgalactiae S2 revealed the presence of repeated motifs (called RA1-A3 and RB1-B3, respectively) which encode Fn binding activity (Lindgren, P.-E., McGavin, M. J., Signäs, C., Guss, B., Gurusiddappa, S., Höök, M., and Lindberg, M. (1993) Eur. J. Biochem. 214, 819-827). Synthetic peptides of 32-37 amino acids, corresponding to individual repeated motifs, were assayed for the ability to inhibit Fn binding to cells of S. dysgalactiae. Within the RA motifs, peptide A2 was 10-fold more active than either A1 or A3, while in the RB motifs, only B3 was active. The same level of activity is observed when these synthetic peptides were assayed for inhibition of Fn binding to cells of Staphylococcus aureus. Likewise, synthetic peptides corresponding to the RD1-D3 motifs, which comprise a ligand binding domain in a Fn receptor from S. aureus, inhibit binding of Fn to both S. aureus and S. dysgalactiae. Assays of chemically modified peptides and peptide fragments derived from chemical or proteolytic cleavage suggest that a conserved core sequence, defined as ED(T/S) (X9,10)GG(X3,4)(I/V)DF, within a 30-amino acid-long segment is present in the active RA and RD motifs. Analyses of the importance of individual residues of this core sequence indicate that the ED(T/S) motif is nonessential, whereas the GG and the (I/V)DF together with additional acidic residues in the C-terminal half of the peptide are required for activity.

Amino Acid Sequence↗
PubMed1993

Two different genes coding for fibronectin-binding proteins from Streptococcus dysgalactiae. The complete nucleotide sequences and characterization of the binding domains.

The binding of Streptococcus dysgalactiae to fibronectin involves fibronectin-binding protein(s) present on the bacterial surface. Previously, we reported the cloning of two different genes coding for cell-wall-associated fibronectin-binding proteins from S. dysgalactiae strain S2 [Lindgren, P.-E., Speziale, P., McGavin, M. J., Monstein, H.-J., Höök, M., Visai, L., Kostiainen, T., Bozzini, S. & Lindberg, M. (1992) J. Biol. Chem. 267, 1924-1931]. The two genes, fnbA and fnbB, have now been sequenced and the primary amino acid sequences of the two fibronectin-binding proteins, FnBA and FnBB, have been deduced. The two proteins have predicted molecular masses of 117 kDa and 122 kDa, respectively, and are organized in a similar way. The fibronectin-binding activities are localized in repeated motifs, 32-37 amino acids long, in the COOH-terminal regions of the proteins. The two fibronectin-binding proteins have heterologous amino acid sequences, except for the COOH-terminal ends which include the fibronectin-binding repeats. The fibronectin-binding regions of the genes have been fused to IgG-binding domains of protein A, utilizing the IgG-binding capacity of the resulting fusion proteins, to facilitate isolation of the fibronectin-binding domains.

Adhesins, Bacterial↗
PubMed1993

Screwdrivers and their use from a Swedish construction industry perspective.

The purpose of this paper is to focus on certain important aspects of screw driver use in occupational work situations, with an emphasis on force exertion and screwdriver use in construction work. Hand tools are involved in many accidents and injuries in the Swedish construction industry. Traditions with in the industry sometimes have a strong influence on what tools are being used and how the work is performed. Manual and pistol-grip powered screwdrivers are the most common tools and the work is often performed with highly repetitive arm elevations, sometimes in constrained postures for long periods of time. Manual screwdriving causes high loads in the forearm muscles. There has therefore been a shift to the use of battery-powered screwdrivers, which have been shown to reduce forearm muscle load considerably, while at the same time increasing production. Factors apart from the tool itself, such as working height, screw-head type and characteristics of the target material, leading to long external shoulder moment arms and high required push forces, are primarily responsible for high loads, particularly in the shoulder muscles. Push reaction forces may exceed 70% of MVC and sometimes account for more than 70% of the external shoulder torque. Fatigue develops rapidly in the shoulder muscles during short-cycled repetitive overhead screwdriving. To reduce the risk of developing injuries from screwdriving in construction work, it is necessary not only to improve screwdriver design, but also to improve posture and to select appropriate screws and material. It is also important to consider the work organization.

Journal Article↗
PubMed1993

The temperature effect on in vitro penetration of sodium lauryl sulfate and nickel chloride through human skin.

Irritant contact dermatitis is a major problem in dermatology. One important group of substances causing irritant dermatitis is detergents. Exposure of the skin to detergents is frequent in both work and domestic environments. In the present paper we have studied how the penetration through the skin, and thus the effect, of the detergent sodium lauryl sulfate (SLS) is altered when the temperature is raised from 22 degrees C to 40 degrees C or 60 degrees C. We found that the penetration of sodium lauryl sulfate increased with increasing temperature. When comparing the increased penetration of sodium lauryl sulfate with the change in NiCl penetration at the same temperatures, we found that the increase in penetration was more pronounced for the detergent. This implies that the detergent also had a different effect on the structure and function of the epidermal barrier itself. The results underline the importance of choosing the right (low) temperature when working with detergent solutions to reduce the risk of developing irritant contact reactions.

Dermatitis, Contact↗
PubMed1993

Quantitative and 3-dimensional analysis of Langerhans' cells following occlusion with patch tests using confocal laser scanning microscopy.

Quantitative and detailed 3-dimensional (3-D) morphological information can be obtained from the same tissue volume using a confocal laser scanning microscope (CLSM). In the present study, we used CLSM for evaluation of Langerhans' cells (LC) in human skin at 0 h, 24 h and 48 h following occlusion with patch tests for 48 h. The relative volume of epidermal CD1a reactivity was quantified with CLSM on 25 microns thick sections stained with indirect immunofluorescence. No statistically significant difference was found when comparing the values obtained on the biopsy specimens from occluded skin (n = 36) with those from non-occluded skin (n = 9). Nor were any statistically significant changes detected in the number of epidermal CD1a+ cells as determined with immunoperoxidase staining between occluded and non-occluded skin. The occlusion produced a transient mild inflammatory reaction with an induced expression of intercellular adhesion molecule-1 (ICAM-1) on keratinocytes and an increased number of CD3+ epidermal lymphocytes. In addition, 3-D reconstructions revealed spatial information on the distribution of LC dendrites towards the skin surface.

Adult↗
PubMed1993

Water and ion distribution profiles in human skin.

Bulk sample x-ray microanalysis (XRMA) of human gluteal skin was performed to provide data on water and ion profiles over the epidermal cross section. All samples were analyzed both in the frozen hydrated state and in the frozen dried state. This allows, for the first time, a quantitative determination of the local water content in different strata of the skin. A steep water gradient was found in the stratum corneum towards the stratum granulosum, while the water content was constant in all deeper layers of the skin, including the papillary dermis. Previously demonstrated distributions over the epidermis of the monovalent ions sodium (Na), potassium (K) and chlorine (Cl) given in concentrations per unit dry weight were confirmed, as were the distributions of phosphorus (P) and sulfur (S). Combining the water and ion distributions, our data indicate the major monovalent ions Na, K and Cl to be in equilibrium between the stratum corneum and the dermis if the assumption is that all monovalent ions are in solution and that all the water of the tissue is available as solvent for the ions. This result does not disprove the existence of an ion transport gradient in the epidermis but sets significant bounds to it.

Body Water↗