Histochemische Untersuchungen �ber die Phosphomonoesterasen der gesunden Haut mit Hinweis auf Befunde bei Hauterkrankungen

Alkaline phosphatase activity and localization during the murine hair cycle

For unknown reasons, the pilosebaceous unit displays prominent alkaline phosphatase (AP) activity, and alterations in AP activity are seen in alopecia areata. The role of AP in hair biology and pathology has been obscured by contradictory reports on the localization and activity of AP during the hair cycle, and by a paucity of instructive models for studying AP functions. Using the C57 BL-6 mouse model for hair research, we have characterized endogenous AP with a simple histochemical developing solution routinely employed for AP immunohistology. This method was selective for AP, and revealed distinctive hair cycle-dependent changes in AP activity and localization. Although the dermal papilla displays unusually strong AP activity during the entire hair cycle, the outer root sheath is AP-positive only during late anagen and early catagen. Strong, rather homogeneous AP activity is seen in the sebaceous gland (SG) only during catagen and telogen. This AP staining pattern indicates hair cycle-dependent changes in SG functions, and differs to some extent from the previously reported AP activity during the hair cycle of various species. We propose a simple and effective technique for follicle classification based on the AP histochemistry of dermal papilla and sebaceous gland, and discuss uses of the C57 BL-6 mouse model for functional AP studies.

Histochemistry in psoriasis. 5'-Nucleotidase in psoriatic parakeratotic horny layer

The 5'-nucleotidase activity in psoriatic and normal human epidermis was studied in comparison to acid phosphatase activity. The optimum pH in normal human epidermis was about 5.0 at room temperature. The activity of both enzymes was found to be high in the transitional zone. Acid phosphatase (non-specific) activity was strongly positive in the psoriatic parakeratotic horny layers whereas 5'-nucleotidase activity in that area was completely absent. The results suggest that the enzyme which degrades nucleoside-5'-phosphate to nucleoside and inorganic phosphate is not acid phosphatase but 5'-nucleotidase. Nuclear preservation in psoriatic hyperkeratosis was attributed to absence or inactivation of specific enzymes of nuclear degradation, such as 5'-nucleotidase, rather than acid phosphatase.

Subcellular distribution of phosphatases, proteinases, and ribonucleases in normal human stratum corneum and psoriatic scales

The subcellular distribution of phosphatases, proteinases, and ribonucleases of normal human stratum corneum and psoriatic scales was determined after differential centrifugation. All psoriatic enzymes showed much increased activities as compared to the normal stratum corneum enzymes. The highest activities of alkaline phosphatase from psoriatic scales could be detected in the nuclear fraction. The main activities of all other tested phosphatases and proteinases were present in the cytoplasmatic fraction. The subcellular distribution of the ribonucleases varied according to the pH value.

Localization of 5'-ribonucleotide phosphohydrolase in regenerating (and normal) limb tissues of the adult newt Notophthalmus viridescens

The regenerating forelimb of the adult newt, Notophthalmus viridescens was investigated for 5'-nucleotidase (5' ribonucleotide phosphohydrolase, 3.1.3.5) acitivity. The newt's humeri were surgically removed, and after a twenty-one-day recovery period, the forelimbs amputated above the elbows. Regenerates were sampled at predetermined times for specific phases in the progress of regeneration, frozen, sectioned in a cryostat, and the sections fixed in 10% cold formol calcium. The Wachstein and Meisel [25] lead procedure at neutral pH was used predominately in these experiments, although tests were also conducted with Gomori's [14] calcium, Allen's [21] highly alkaline procedures. The substrates used to obtain specific enzyme reactions were adenine, cytosine, guanine, uracil and inosine 5'-monophosphate nucleotides. Sodium beta-glycerophosphate served as a non-specific phosphomonoesterase substrate, distilled water replaced substrate, and inhibitors such as zinc and cyanide ions were used as control measures to assist in increasing the precision in interpreting the results obtained. The most reactive 5'-nucleotidase (5'-Nase) loci were in the walls of the blood vascular system, mysial and neural sheaths, dermis, and periosteum: the principal cells involved were macrophages, endothelium of blood vessels, and fibrocytes of connective tissues. A moderate enzyme response was elicited from secretory cells of some of the subcutaneous glands, hypertrophied chondrocytes and osteogenic centers, chondrocytes in the articular regions and within red blood cells and leucocytes. Normal, injured and degenerating, or regenerating striated muscle and nerve fibers were judged unreactive for 5'-Nase. The epidermis and wound epithelium displayed negative responses for 5'-Nase. Cells forming the regeneration blastema were 5'-Nase reactive during the early formative phase, but with growth and development of the blastema into bulb and conic forms, these cells did not respond for this enzyme-activity. One suggestion offered is that the absence of 5'-Nase in cells of the blastema may be related to the lack of an adequate blood-vascular supply. Several functions of 5'-Nase in normal and regenerating tissues are discussed. A basic conclusion reached is that 5'-nucleotidase hydrolyses may be more involved in fundamental anabolic than in catabolic metabolism.