Search PubMed⌕ Search

Biomedical subjects

W R Otto

Publications and source records attributed to W R Otto.

29 records · Page 2Linked to original sources
PubMed1995

Survival of allogeneic cells in cultured organotypic skin grafts.

Organotypic cultures of human skin were made using dermal fibroblasts seeded into a type I collagen gel overlaid with epidermal keratinocytes. Full-thickness excision of tattoos was performed on five patients, three of whom received sex-mismatched allografts. Patients were not immunosuppressed. Biopsies were obtained up to 3.5 years later. In situ hybridization of the PHY2.1 repetitive Y chromosome sequence revealed male fibroblasts and keratinocytes at 11 weeks and 2.5 years in the two female patients grafted with male cells. Structural components in the dermal substitute matured with time, and elastic fibers formed an interlacing meshwork by 18 months. Electron microscopy of the dermal-epidermal junction of an organotypic allograft revealed anchoring fibrils that had normal features at this time. Hyperemia of early grafts settled and contour correction was maintained, while repigmentation was variable. Hypertrophic scars did not occur, and graft contracture was never more than 20 percent. We conclude that this organotypic skin graft shows potential toward the goal of allogeneic skin replacement in a one-step procedure.

Adult↗
PubMed1994

[Texture analysis: a new method for evaluating ultrasound imaged lesions of the breast].

Echogenicity and echostructure in sonomammography are essential criteria to determine the malignancy of a breast tumor. Looking for a correlation between echostructure of an ultrasound image and its histopathology a texture analysis was performed. Ultrasonic examinations were carried out by means of a 7.5-MHz linear scanner under standardized conditions. 71 mammasonographic findings were documented by video tape, each tumor in 2 dimensions. In a second step 'the region of interest', that means the whole tumor area, was marked and statistically analyzed by a dedicated computer system. The values of 23 first- and second-order statistical texture parameters were compared with the histopathology of the tumor. They include grey level histogram, Fourier analysis and cooccurrence matrix. The most important results were obtained in the histogram analysis. An obvious distinction could be worked out concerning carcinomas, adenomas, mastopathic tumors, and fat necrosis. Except the difference between carcinomas and adenomas this distinction was statistically significant. Fourier analysis and coocurrence matrix significantly separate fibrocystic lesions, fat necrosis, scars, and cystic structures from malignant tumors. Furthermore the maximum value method was used to compare the different parameters with regard to their capability of discriminating benign and malignant tumors. The extreme values of 100% were mostly observed in the case of seromas and scars. A significant difference was found by histological grading of carcinomas, too. Highly differenciated carcinomas show capability of results comparable to those of adenomas. By means of a computer texture analysis program it is possible to find a correlation between echostructure and histopathology of breast tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1992

Fluorimetric DNA assay for cell growth estimation.

A growth assay using the fluorescent dye Hoechst 33258 has been developed which allows sensitive and rapid analysis of the DNA content of a variety of cell types including keratinocytes and mucus-secreting cells, and which requires a minimum of liquid handling. The assay can detect as few as 500 diploid human cells, and is compatible with the simultaneous detection of [3H]thymidine incorporation in the same cultures.

Animals↗
PubMed1990

Dermal equivalents.

Explore the source record for details and available documents.

Artificial Organs↗
PubMed1989

Cultured composite skin grafts: biological skin equivalents permitting massive expansion.

After assessment in mice, a biological skin equivalent consisting of cultured fibroblasts in a collagen gel overlain with cultured keratinocytes was applied to three patients who had had tattoos excised. In all patients the grafts took well with good cosmetic results and little or no contracture. A biopsy at 4 weeks showed that the central graft area had a fully differentiated epidermis and a mature dermis without adnexae.

Adult↗
PubMed1989

12-Hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) does not stimulate proliferation of human neonatal keratinocytes.

We have developed an assay to study the effect of drugs on the proliferation of neonatal human skin-derived keratinocytes in vitro. Expanding populations of neonatal keratinocytes were cultured in low concentrations (0.5%) of fetal calf serum for up to 12 d. Growth of the cultures was determined by measurement of DNA using a sensitive fluorimetric assay. Addition of 10(-9)-10(-6) M 12(RS)-hydroxy-5,8,10,14-eicosatetraenoic acid (12(RS)-HETE) neither stimulated keratinocyte proliferation nor enhanced the incorporation of [3H]thymidine. The ability of neonatal keratinocytes in low serum medium to respond to exogenous factors was demonstrated by increased growth in response to a mixture of cholera toxin, hydrocortisone, and epidermal growth factor. Confluent keratinocyte cultures in 10% human AB serum exposed to 12(S)-HETE for 72 h also showed no changes in DNA, [3H]thymidine incorporation, or labeling index. Metabolism of 12(S)-[3H]HETE was greater in cultures containing low concentrations of serum but there was no evidence for the formation of 12,20-dihydroxyeicosatetraenoic acid.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1979

The relationship between protein turnover and energy balance in lean and genetically obese (ob/ob) mice.

1. Groups of lean and genetically obese (ob/ob) mice were adapted to varying energy intakes and the rates of total protein turnover in liver, gut and kidney were measured. 2. Lean mice gained less weight when fed above maintenance and lost less weight when fed below maintance than obese mice. 3. Hepatic protein turnover (mg/d) was sigmoidally related to digestible energy intake in lean mice but showed no significant changes with dietary intake in obese mice. 4. The changes in protein turnover resulted from changes in both the half-lives of protein synthesis and catabolism and in tissue protein content. 5. In the lean mice, protein turnover in kidney and gut was not significantly changed with increasing energy intake until the highest level was reached. 6. The findings suggest that protein turnover may be an important cycle for the regulation of energy balance in mice and that this cycle is impaired in the genetically obese (ob/ob) mice.

Animals↗
PubMedDate not supplied

A study of protein synthesis in cells cultured from involved psoriatic skin.

Using histochemical techniques an abnormal programme of epidermal differentiation has been well documented in psoriasis. In order to characterise further the biochemistry of this process we have cultured dermal fibroblasts and epidermal keratinocytes from involved psoriatic skin. This has facilitated metabolic radiolabelling of skin cells and analysis of protein synthesis by two-dimensional polyacrylamide gel electrophoresis. The expression of keratin and differentiation markers was identical to that of normal keratinocytes, suggesting that psoriatic epidermal differentiation is not truncated in vitro as has been postulated to be the case in vivo. Low molecular mass components (5-8.5 kDa), previously shown to be upregulated in suprabasal keratinocytes, were detected in epidermal fractions from psoriatic skin enriched for basal cells. Of special interest was a component of 26 kDa, pI 5.9, which was highly upregulated in psoriatic as compared to normal cultured keratinocytes and was not detected in fibroblasts. These findings are in accord with a qualitatively abnormal pattern of differentiation for keratinocytes in the involved psoriatic epidermis.

Autoradiography↗