Filamentous protein of basal cell epithelioma: characteristics in vivo and in vitro.

The sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) pattern of the citrate-soluble fibrous protein isolated from human basal cell epitheliomas showed polypeptides with molecular weights of 43,000, 45,000, and 59,000. These polypeptides, found in the protein of normal epidermis, were present in a different proportion in this tumor tissue. Basal cell epitheliomas were cultured by the use of killed murine 3T3 feeder layers but only when 10(-9) M cholera toxin was present. The SDS-PAGE pattern of fibrous protein from cultured tumor cells was identical to the pattern of cultured normal human epidermal cells, and cornified cell envelopes were found in both types of cultures. Electron microscopy showed stratified cells that contained desmosomes, tonofilaments, and keratohyalin granules.

Comparison of stratum corneum and hair fibrous proteins.

The Tris-urea-mercaptoethanol (pH 9) soluble fibrous proteins of hair and stratum corneum have been compared in a number of animals. The 2 tissues show different urea (pH 8.3) and SDS polyacrylamide gel electrophoretic patterns and vary in amino acid composition. Cyanogen bromide cleavage was done on human stratum corneum and hair fibrous proteins and found to give different fragments by electrophoresis. Antibodies to stratum corneum protein did not react with hair protein and vice versa. Although the 2 types of fibrous proteins have the same helical structure as shown by x-ray diffraction analysis, their differences in composition may be important for specific interactions with other macromolecules.

Effect of therapy on keratin polypeptide profiles of psoriatic epidermis.

The sodium lauryl (dodecyl) sulfate polyacrylamide gel electrophoresis (SLS PAGE) patterns of keratin polypeptides were followed in 29 patients with psoriasis who were treated with middle wavelength ultraviolet (UV) radiation (UV B), oral methoxsalen, and long wavelength UV radiation (PUVA), or systemic antipsoriatic therapy. The keratin patterns from the Malpighian layer reverted to normal in several weeks, while those of the stratum corneum keratin reverted more slowly, often after clinical clearance of the lesions. These data may indicate that therapy should not be discontinued until there is production of normal stratum corneum polypeptides.

The keratin polypeptides of psoriatic epidermis.

The polyacrylamide SDS electrophoretic pattern of protein extracted from the stratum corneum obtained by scraping the surface of involved skin of patients with psoriasis was different from that of uninvolved skin and normal controls. The pattern from superficial scales was similar to that of whole stratum corneum in the case of involved psoriatic epidermis but different in uninvolved and normal epidermis. These data indicate that the changes which are observed in the structural proteins during normal keratinization are not seen in involved psoriatic epidermis. In addition, the relative proportion of keratin polypeptides was different in involved psoriatic epidermis compared to normal skin. That these changes are not specific for psoriasis was shown by finding similar electrophoretic patterns with stratum corneum proteins from patients with other keratinizing disorders.

The effects of acute bleeding on acid-base balance erythropoietin (Ep) production and in vivo P50 in the rat.

The mechanism of erythropoietin (Ep) production after acute haemorrhage has been thought to be due to a reduction in blood volume and tissue perfusion leading to tissue hypoxia. In the present study we have evaluated the effect of acute haemorrhage in the rat on the acid-base status, the red cell affinity for oxygen in vivo, and Ep production. Within a few hours after acute blood loss there was a respiratory alkalosis with an increase in blood pH, a decrease in pCO2 and an increase in the red cell affinity of Hb for oxygen in vivo that was temporally related to an increase in Ep production. Within 24 h after the acute haemorrhage, the blood pH AND PCO2, red cell affinity for oxygen in vivo, and Ep level returned towards normal. The decrease in in vivo red cell affinity for oxygen was associated with an increase in red cell 2,3-DPG levels and a decrease in Ep production.