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Biomedical subjects

T E Larsen

Publications and source records attributed to T E Larsen.

At least 19 recordsLinked to original sources
PubMed1998

[Prevention and early diagnosis of malignant melanoma].

A Norwegian melanoma project was carried out in 1989-1993 as a joint study by the dermatological, surgical, oncological, and pathological departments at the five university hospitals in Norway, Of 4,582 patients (2,894 women, 1,688 men) diagnosed and treated at the Department of Dermatology, Ullevål Hospital, 1,347 patients (833 women, 514 men) were included in the analysis, which consisted of a clinical evaluation and pathological investigation of their excised pigmented lesions. In all, 66 malignant melanomas were diagnosed, including 50 superficial spreading melanomas, seven lentigo maligna melanomas, eight nodular melanomas, and one acral lentiginous melanoma. Persons with red hair and skin type I/II were at increased risk of developing malignant melanoma. Superficial spreading melanomas excised during the study period had a significant lower histological thickness compared with those lesions excised before the study period.

Female↗
PubMed1998

[Biopsy in non-neoplastic skin diseases].

The Department of Dermatology at Ullevål Hospital wanted to reveal any diagnostical problems with skin biopsies taken from patients in the Out-patient Clinic. 200 non-tumour skin biopsies from 200 patients were studied retrospectively (100 biopsies from 1986 and 100 from 1995/96). The tentative diagnosis coincided with the pathological anatomical diagnosis in 57.5%(n = 115) of the cases. Of the 200 patients, 22%(n = 44) had still not been given a specific diagnosis after biopsy. This study indicates that skin biopsy is of diagnostical help, but that closer cooperation between the pathologist and the clinician is probably necessary in order to increase the proportion of specific dermatological diagnoses.

Aged↗
PubMed1994

Aneuploidy in benign tumors and nonneoplastic lesions of musculoskeletal tissues.

BACKGROUND: Aneuploidy in DNA flow cytometry (FCM) of musculoskeletal tumors is generally considered to be a sign of malignancy. Previously, giant cell tumor of the bone has been reported to contain aneuploid (near-diploid) DNA stemlines. Otherwise, only spordic cases have been reported. The authors wanted to study the relationships among DNA FCM, histology, and clinical course of nonmalignant musculoskeletal lesions. METHODS: Twenty-eight histologically benign tumors and seven nonneoplastic lesions were subjected to DNA FCM: After tissue preparation mechanically and with ribonuclease and trypsin, the isolated nuclei were stained with propidium iodine using chicken and rainbow trout erythrocytes as controls. In the DNA FCM histograms, ploidy and cell cycle fractions were determined using a computerized mathematical model. The histologic diagnoses were made without knowledge of the DNA FCM results. RESULTS: Aneuploidy was found in eight lesions. A shoulder in the diploid peak, suggesting a diploid and a near-diploid population, was found in DNA histograms of a condensing osteitis of the clavicle (a benign inflammatory process) and of a giant cell tumor of bone. The latter lesion also had a tetraploid population. Six benign tumors--two enchondromas, one osteochondroma, one subcutaneous and one intramuscular lipoma, and a calcifying aponeurotic fibroma--showed clear aneuploidy with separate peaks. The S-phase fraction was less than 10% in all cases. The highest aneuploid population, DNA index = 1.70, in a subcutaneous lipoma, was small, with an undetectable S phase. Despite nonradical operations in seven lesions, no recurrences were observed during a median follow-up of 49 months (range, 28-73 months). CONCLUSIONS: Small aneuploid populations with low DNA synthetic activity may be compatible with a benign histologic picture and uneventful clinical course of the musculoskeletal lesion.

Adolescent↗
PubMed1990

The inhibiting effect of PABA on photocarcinogenesis.

The efficacy of a 5% solution of para-aminobenzoic acid (PABA) to protect against photocarcinogenesis was tested in 6 groups, each of which contained 30 light pigmented hairless mice. The light source was a Phillips TL 40 W/12, which mainly emits UVB. PABA significantly retarded the tumor induction time (p less than 0.05) and reduced both tumor yield and carcinoma yield (p less than 0.05). The dorsal skin of the mice was removed and weighed. The mean weight of UVR-exposed mice skin protected with PABA did not differ from that of the controls, but in the non-protected UVR-exposed mice the skin samples were significantly heavier (p less than 0.05).

4-Aminobenzoic Acid↗
PubMed1990

Serum carotene concentrations in normal infants and children.

The blood of 444 healthy Canadian children (246 males and 198 females) aged 6 days to 18 years was analyzed to determine the concentration of serum carotene. The serum carotene concentration was very low in the first six months of life. In the first three months of life, breast fed infants had significantly higher serum carotene concentration than infants who were formula fed. Infants 7 to 12 months of age had the highest serum carotene concentration. The serum carotene concentration dropped off after the age of one year and remained low until two years of age. After two years of age, the serum carotene concentration showed a progressive and small rise until the age of six to seven years and then fell until the age of 14 to 18 years. The serum carotene concentration did not appear to vary according to the sex of the child except for infants 7 to 12 months of age. In infants 7 to 12 months of age, girls had a higher serum carotene concentration. The measurement of the serum carotene concentration is a simple screening test for fat malabsorption. Our study provides the normal range of serum carotene concentration for children of various age groups.

Adolescent↗
PubMed1990

Seasonal variations of pigmented naevi. Intercorrelations of clinical and histological variables with special reference to seasonal variation.

During 1984, junctional and compound naevi were registered significantly more often during the summer half-year (May-October) than the total number of naevi, which showed no seasonal variation. A series of 342 of these junctional and compound naevi have been the subject of a blind histological classification. Clinical information was obtained by a questionnaire mailed to the patients. The intercorrelations of 19 histological and 10 clinical variables were studied by chi 2-test. The seasonal variation of these variables was further studied by chi 2-test and by Hewitt's test. Patient's hair colour, eye colour and sex as well as mitoses and localization showed a significant correlation to season of the year. The trends of these findings, compared with the information about tumour duration, indicate a short-term latency effect of UV light on naevi which are excised during the summer half-year.

Adolescent↗
PubMed1988

Clinical and histological intercorrelations in pigmented naevi indicating potential melanoma precursor lesions.

A series of 577 pigmented naevi from an equal number of patients has been studied histopathologically without access to clinical information. Later the histological findings have been compared with clinical information obtained by sending a questionnaire to the patients. The correlations between the many histological and clinical variables have been studied. Patients with a red or fair hair colour, a freckled, easily sunburnt skin type and/or a poor suntanning ability have the tendency to develop irregular and atypical naevi. Histological variables like nuclear atypia, mitoses, lymphocyte reaction, fibrosis and "shoulder"-phenomenon regarding the growth pattern of naevi are correlated to this delicate skin type. These findings support til theory that irregular and atypical naevi may be potential precursors to malignant melanomas as patients with this skin type belong to the melanoma risk group.

Adult↗
PubMed1988

The evaluation of possible melanoma risk groups of patients in a series of pigmented naevi. Clinical and histological intercorrelations.

The trends of the clinical/histological intercorrelations in two series of pigmented naevi have been compared. One series of naevi represents patients who are habitual sunbathers and/or who have travelled to Southern sunny climates. The other series includes naevi from easily sunburned patients. The sunburner-group is correlated to histological features such as mitoses, atypia and fibrosis of the tumour as well as to an irregular/atypical tumour type. Such trends are not found in the other target group. The sunburners have a poor ability to suntan, while the sunbather group includes good suntanners. This indicates the importance of the melanin UV-filter effect of the skin as a protection against the promotion of potential MM-precursors, such as irregular/atypical naevi.

Humans↗
PubMed1987

Scleredema adultorum associated with a monoclonal gammopathy and generalized hyperpigmentation.

Scleredema associated with a monoclonal gammopathy and generalized skin pigmentation is described in a 56-year-old man with hyperlipoproteinemia and cardiovascular disease. The patient had IgG-lambda paraproteinemia, without any evidence of multiple myeloma or immunoglobulin deposition in affected skin. Ultrastructural studies of pigmented lesional skin showed increased transfer of melanosomes to basal keratinocytes and dermal melanophages containing complex melanosomes. In addition, cytoplasmic, electron-opaque lipid droplets were seen in approximately every third keratinocyte or melanocyte, while only an occasional dermal cell contained lipid droplets. The hyperpigmentation appeared to be directly related to the scleredema, while the lipid deposition in skin was a likely consequence of the hyperlipoproteinemia. The findings further support the contention that paraproteinemia and hyperpigmentation may, in some patients, be associated features of scleredema adultorum.

Histocytochemistry↗
PubMed1986

Epidermal and dermal distribution of a myelomonocytic antigen (L1) shared by epithelial cells in various inflammatory skin diseases.

The L1 antigen is a major cytosol component of human granulocytes that may also be expressed by macrophages and epithelial cells. Its epidermal and dermal occurrence was investigated in formalin-fixed routine biopsy material from eleven different inflammatory skin disorders. Localization was performed with a rabbit antiserum to L1 applied in an unlabeled antibody peroxidase-antiperoxidase method. L1 antigen was not found in normal skin except in epithelial cells of pilosebaceous units. However, epidermal L1 antigen was demonstrated in every biopsy specimen from lupus erythematosus, lichen planus, dermatitis herpetiformis, and atopic dermatitis, whereas granuloma annulare test results were usually negative. The occurrence of dermal L1 antigen depended on the composition of the inflammatory infiltrate; specimens rich in neutrophilic granulocytes (e.g., dermatitis herpetiformis) were particularly strongly stained. Extracellular dermal staining was also seen, especially in areas adjacent to accumulation of positive leukocytes. The varying epidermal occurrence of L1 antigen in skin diseases probably signified different degrees of proliferative activity of the epithelial cells and could apparently not be ascribed to uptake from the dermis.

Adolescent↗
PubMed1986

Polymorphous light eruption: the properties of a UVA-induced PLME patient group.

Experimental induction of PLME lesions in 22 patients, using a pure, high-intensity UVA light source is reported. Fourteen patients had a reduced MED value for either UVB (11 patients) and/or UVA (7 patients). The UVA-SUN 2000 dose required to provoke a positive PLME reaction varied from 26 to 104 J/cm2. The small papular PMLE-type patients were shown to be more photosensitive and the UVA provocation doses required exceeded 50 J/cm2 in 20/22 patients. Lesional immunoglobulin deposition along the BMZ was seen in 3 patients while lesional BMZ complement deposits occurred in 9/15 patients, 2 of whom had similar findings in the dermal capillaries. Complement deposition occurred in non-irradiated control sites in 4 patients. The immunohistologic findings, for reasons given, fail to support the hypothesis of an immune cell-mediated response as the primary event in the pathogenesis of PMLE.

Biopsy↗