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Biomedical subjects

L Lundgren

Publications and source records attributed to L Lundgren.

At least 19 recordsLinked to original sources
PubMed1998

A new whole-body exposure chamber for human skin and lung challenge experiments--the generation of wheat flour aerosols.

A new whole-body exposure chamber for human skin and lung challenge offers possibilities for experimental exposure challenges carried out in clinical practice, for exposure of patients, in research and for investigations of the effects of exposure on the skin and in the respiratory tract. The chamber system can be used for both aerosols and gases. Dynamically controlled, the chamber is relatively easy to operate and to clean. Air exchange rates can be varied between 6-12/h. Initial studies with wheat flour have been carried out. The homogeneity and stability of the wheat flour aerosol concentration (the spatial and the temporal variation) inside the chamber can be kept at acceptable levels.

Administration, Cutaneous↗
PubMed1995

Characterization of current exposure to man-made vitreous fibres (MMVF) in the prefabricated house industry in Sweden.

The exposure to man-made vitreous fibres (MMVF) was investigated at 11 Swedish plants manufacturing prefabricated wooden houses. Current fibre levels were studied by monitoring personal exposure using the membrane filter technique. All samples were analysed by phase contrast optical microscopy (PCOM) according to Swedish standard rules; they were also analysed using a set of modified criteria for fibre counting, developed for this study, which in addition also required straight, parallel and/or convergent edges of the fibres. The objective of this alternating counting method, the modified fibre method, was to exclude fibres with appearance other than MMVF, that might be present in the wood industries. The method was validated by scanning electron microscopy (SEM). In all, 120 samples were taken and 273 analyses were performed. The mean exposure (GM), analysed by the standard method, was for insulators 0.10 f ml-1 (range 0.03-0.30 f ml-1) and for woodcutters 0.09 f ml-1) (range 0.05-0.19 f ml-1). Analysed by the modified fibre method the insulators were exposed to 0.029 f ml-1 (range 0.013-0.077 f ml-1 and the cutters to 0.021 f ml-1 (range 0.014-0.033 f ml-1). A significant difference was observed between the exposure for near-field workers/job titles and far-field workers/job titles. Analysis of fibre levels by the modified fibre method indicated that only a minor proportion, around 25%, of the total airborne fibres were MMVFs. The reliability of the alternative modified counting method was high, and a high correlation (r = 0.94) with the SEM results was also achieved.

Calcium Compounds↗
PubMed1994

Pseudomalignant spindle cell proliferations of the urinary bladder.

Twelve cases of polypoid, nonrecurrent, pseudomalignant spindle cell proliferations of the urinary bladder (eight women and four men) were analyzed. Two patients had a simultaneous urinary bladder carcinoma. The lesions were characterized by proliferating spindle- or strap-shaped cells, which on electron microscopic examination (performed in all 12 cases) revealed characteristics of fibroblasts and myofibroblasts. The cells showed immunoreactivity for vimentin in all cases, for alpha-smooth muscle-specific and muscle-specific actin in six cases, for cytokeratins in five cases, and for CD 34 in one case. No immunoreactivity was observed for desmin, myoglobin, epithelial membrane antigen, S-100 protein, endothelial cell antigen (H and Y), CD 68, or factor VIII RAG. Immunoreactivity for Ki-67 and proliferating cell nuclear antigen was detected in up to 30% of the spindle cell nuclei. The static cytometric DNA analysis revealed a diploid, or in two cases a hyperdiploid, stem cell line. An awareness of this type of spindle cell lesion and its immunophenotypic characteristics and diversity is of importance to avoid an erroneous diagnosis of spindle cell sarcoma (in particular leiomyosarcoma and embryonal rhabdomyosarcoma) or spindle cell carcinoma.

Actins↗
PubMed1993

Infantile rhabdomyofibrosarcoma: a high-grade sarcoma distinguishable from infantile fibrosarcoma and rhabdomyosarcoma.

Three patients with a predominantly fibrosarcomatous, desmoplastic, and fascicular spindle-cell sarcoma, resembling that of infantile fibrosarcoma but with ultrastructural and immunocytochemical evidence of rhabdomyoblastic differentiation, are described. The tumors were compared light and electron microscopically and immunocytochemically with six classical cases of infantile fibrosarcoma of the desmoplastic type. The three tumors occurred in two girls and one boy who were between 1 and 3 years of age. Ultrastructurally, the tumor cells primarily demonstrated fibroblastic and myofibroblastic features, but there were also tumor cells with sarcomere-like structures. The spindle-shaped, fibroblast-like tumor cells expressed vimentin, desmin, and smooth muscle-specific and sarcomere-specific actins. In one tumor peculiar intracytoplasmic inclusions were observed by light and electron microscopy. The immunocytochemical analysis indicated that these bodies contained all types of thin and intermediate filaments. In short-term cell cultures the tumor cells of two examined tumors revealed immunoreactivity for vimentin, smooth muscle-specific actin, and desmin. Cytogenetically, both tumors displayed a similar chromosomal pattern. One tumor contained two abnormal clones with monosomy 19 and monosomy 22, respectively, and the other tumor revealed a single clone with monosomy 19. In addition, both tumors contained clones with a normal karyotype. Two of the patients with metastatic spread died within 2 years of the primary operation. The third patient is alive with a local recurrence. The three tumors described here deviate from infantile fibrosarcoma in terms of their clinical, ultrastructural, immunocytochemical, and cytogenetic characteristics. The descriptive term "infantile rhabdomyofibrosarcoma" is suggested. The present investigation calls for detailed studies of tumors diagnosed as infantile fibrosarcomas that have metastasized and followed a fatal course.

Child, Preschool↗
PubMed1992

Bioassay-guided isolation of serotonin from fruits of Solanum tuberosum L.

An ethanol extract of the fruits of Solanum tuberosum was partitioned between water and petroleum ether. The aqueous fraction had contractive effect on the isolated guinea-pig ileum. Chromatography of this fraction on Sephadex LH-20 and silica gel was monitored by the guinea-pig ileum test and resulted in isolation of serotonin. HPLC analysis of the content of serotonin in fruits, leaves and tubers of the plant, showed that the fruits and leaves contained 7.5 micrograms and 2 micrograms, respectively, of serotonin/g fresh weight. In agreement with previous observations, no serotonin was detected in the tubers.

Animals↗
PubMed1992

Proliferative myositis and fasciitis. A light and electron microscopic, cytologic, DNA-cytometric and immunohistochemical study.

Two cases of proliferative myositis, four cases of proliferative fasciitis and one mixed form of proliferative myositis and fasciitis have been analyzed in terms of cell differentiation and DNA content. Light microscopically, the lesions were characterized by a mixture of proliferating spindle-shaped cells and uni-, bi- or occasionally multinucleated ganglion cell-like cells. The spindle cells showed ultrastructural features and immunohistochemical properties, including an immunoreactivity for smooth muscle-specific actin, indicative of a myofibroblastic differentiation. The ganglion cell-like cells displayed some resemblance to active osteoblasts ultrastructurally and differed immunohistochemically from the spindle cells by being non-immunoreactive for smooth muscle-specific actin. None of the two cell types showed immunoreactivity for desmin, myoglobin or factor VIII RAG. It is suggested that the two cell types represent different lines of cell differentiation. The cytologic features in smears, as seen in two cases of proliferative fasciitis and one case of proliferative myositis, are considered to be characteristic of these lesions and to permit the diagnosis to be made by fine-needle aspiration. In two of the cases, the lesion was diagnosed only cytologically and thereafter disappeared spontaneously within a month. Cytometric DNA measurements, using two different image analysis systems on Feulgen-stained sections and smears, revealed a "diploid" spindle-shaped cell population with a variable proportion of cells with scattered DNA values. The ganglion cell-like cells differed from the spindle cells by having a broad DNA peak in the diploid region and additional peaks in the tetraploid region, as well as a higher proportion of cells with scattered DNA values compared with those of the spindle-shaped cells. The results of the quantitative DNA analysis are well in keeping with the benign and proliferative nature of these lesions. However, with the technique used here, quantitative DNA analysis, does not distinguish these pseudosarcomatous fibrous lesions from diploid and tetraploid soft tissue sarcomas.

Actins↗
PubMed1991

Intermediate and fine cytofilaments in cutaneous and subcutaneous leiomyosarcomas.

The expression of fine and intermediate cytofilaments in 10 cutaneous and seven subcutaneous leiomyosarcomas was studied immunohistochemically. All the tumors contained tumor cells which showed a positive immunoreactivity for desmin in formaldehyde-fixed and paraffin-embedded sections, but none of the seven anti-desmin antibodies used alone produced a distinct positive staining in all the tumors. A lack of correspondence in terms of immunoreactivity between tumor cells and the supposed muscle of origin was observed, especially in the subcutaneous leiomyosarcomas. In all cases, antibodies to muscle-specific and smooth muscle-specific actin were found to produce a positive staining in both the tumors and the supposed muscle of origin. Vimentin was detected in 8/10 cutaneous and 4/7 subcutaneous leiomyosarcomas, while the supposed muscle of origin was positive in 3/10 and 7/7 cases, respectively. Four of the cutaneous and three of the subcutaneous leiomyosarcomas contained tumor cells which stained positively for cytokeratins, while the supposed muscle of origin showed no positivity. It thus appears that a phenotypic shift in terms of vimentin and cytokeratin expression occurs in the tumor cells of cutaneous and subcutaneous leiomyosarcomas compared with the supposed muscle of origin. It is recommended that more than one monoclonal anti-desmin antibody is used to characterize these tumor entities. It is also concluded that the immunoreactivity for muscle-specific actins in superficial leiomyosarcomas is more constant, although less specific, than that of desmin and that the demonstration of the simultaneous expression of muscle-specific actins and desmin is helpful.

Actin Cytoskeleton↗
PubMed1989

Intermediate and fine filaments of vascular leiomyomas (angiomyoma), leiomyoma and leiomyosarcomas of large veins.

The expression of fine and intermediate filaments in 10 cases of leiomyosarcoma originating from a large vein, 9 cases of vascular leiomyoma (angiomyoma) and one case of a leiomyoma originating from the wall of the saphena magna vein was studied immunohistochemically by using 6 different anti-desmin antibodies, one anti-vimentin antibody and 2 antibodies to muscle-specific isoforms of actin. All the benign tumors and all the leiomyosarcomas of a large vein as well as the vein of origin were positively stained for desmin. The staining results obtained using the different anti-desmin antibodies varied considerably, however, and formaldehyde-fixed tissues were apparently inappropriate for some of them. No single anti-desmin antibody produced a positivity in all cases, and the extent and distribution of the positivity varied by being irregular and patchy in the leiomyosarcomas and in the muscle walls of the veins, while the benign tumors generally revealed a more uniform and strong positivity. Antibodies to muscle-specific and smooth muscle-specific actin produced a positive staining in all the benign tumors, as well as all the leiomyosarcomas and the veins from which they originated. A strong and uniform positivity was observed in the benign tumors and muscle walls of the veins, while the positivity in the leiomyosarcomas was more irregular, as it was for desmin. Vimentin was constantly expressed in the benign tumors and in the veins of origin, but only in 5/10 of the leiomyosarcomas. It is concluded from this study that the immunohistochemical demonstration of desmin, utilizing a monoclonal antibody appropriate to the type of fixation used, and muscle specific isoforms of actin, provide strong support to the light-microscopic diagnosis of leiomyosarcoma of venous origin.

Actins↗