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Biomedical subjects

K S Stenn

Publications and source records attributed to K S Stenn.

At least 55 records · Page 3Linked to original sources
PubMed1989

Dispase, a neutral protease from Bacillus polymyxa, is a powerful fibronectinase and type IV collagenase.

Dispase, a neutral protease isolated from culture filtrates of Bacillus polymyxa, has proven to be a rapid, effective, but gentle agent for separating intact epidermis from the dermis and intact epithelial sheets in culture from the substratum. In both cases it effects separation by cleaving the basement membrane zone region while preserving the viability of the epithelial cells. Because it is not known what or where in the basement membrane zone Dispase cleaves, we set up studies to define its substrate specificity. Using purified basement membrane components and sodium dodecyl sulfate-polyacrylamide gel electrophoresis we show that Dispase cleaves fibronectin and type IV collagen, but not laminin, type V collagen, serum albumin, or transferrin. The action of Dispase on collagen appears to be selective for type IV collagen in that several stable degradation products are formed, whereas the enzyme degrades type I collagen only minimally. In newborn human skin, as seen by electron microscopy, Dispase removes the lamina densa, rich in type IV collagen, but preserves the anchoring fibrils (structures known to contain type VII collagen) and the epidermal cells. Because its action is so selective, it suggests that Dispase can serve as a powerful tool for dissecting epithelial-mesenchymal interactions.

Basement Membrane↗
PubMed1989

Angiogenic properties of normal and psoriatic skin associate with epidermis, not dermis.

Psoriasis is a chronic inflammatory and proliferative epidermal skin disease associated with prominent new vessels in the dermis. Heretofore, unresolved was the question which skin element causes stimulation of vessel formation in this lesion: the epidermis, the dermis, vessels themselves, inflammatory cells, and so forth. It has been argued that the dermis by means of its vessels is responsible for the rapid and prominent epidermal growth and that psoriasis is simply a dermal-induced epidermal disease. Recognizing that vascular proliferations do not occur in the absence of an angiogenic stimulus we asked where in psoriatic skin is that angiogenic element found. By using the rabbit cornea angiogenic assay, the vessel-stimulating properties of epidermis and dermis (separated after cold trypsinization overnight), collected from psoriatic-plaque skin and normal skin both nonpsoriatic and psoriatic patients, were measured. The corneas were examined on days 2, 4, 8, 10, and 12 and graded from 1 to 5+ for vessel growth. Psoriatic plaque epidermis revealed a 4 to 5+ stimulus (8 of 12 corneas). Epidermis from normal subjects or from nonlesional psoriatic patient skin also revealed a 4 to 5+ stimulus (3 of 5 and 5 of 8, respectively). In no case was the dermal implant from normal (7 implants) or psoriatic patients (3 implants of lesional skin) angiogenic. The angiogenic activity of epidermis is stable to freezing and boiling. This study indicates that the vessel-stimulating properties of psoriatic and nonpsoriatic skin are associated with the epidermis and that the developing psoriatic lesion may involve complex epidermal to dermal as well as dermal to epidermal signals.

Adult↗
PubMed1989

The induction of anagen hair growth in telogen mouse skin by cyclosporine A administration.

One clinical complication of immunosuppressive cyclosporine A (CsA) therapy is the stimulation of hair growth. Since few pharmacologic agents cause hypertrichosis, CsA appears particularly interesting for investigating the mechanisms which control normal hair formation. Previous investigators have shown that CsA affects the hair growth of the laboratory rat, several genetic variants of mice, as well as humans, and they have concluded that CsA influences keratinization predominantly. Using a well-defined in vivo assay which measures the induction of hair follicle growth, we report here that CsA induces resting (telogen) follicles to enter active growth (anagen) in normal laboratory mice (C57 B1-6), i.e., animals with a normal hair cycle. The experiments indicate that the rate of anagen induction is dependent on the dose, time course, and method of administration and that it may be mediated via a direct action of CsA on the skin and its appendages. These studies suggest that understanding the molecular mechanisms of CsA action on hair growth will help elucidate the mechanisms of normal anagen induction.

Administration, Topical↗
PubMed1988

Malignant blue nevus. Case report and literature review.

A well-documented case of malignant blue nevus is presented, along with an in-depth review of the literature. Malignant blue nevus is a rare form of malignant melanoma. A cellular blue nevus is the precursor lesion. The scalp is the most common site. The tumor often presents clinically as a progressively enlarging or multinodular blue-black lesion. The histologic pattern is fascicular dense collections of pigmented, pleomorphic spindle cells. Because of marked regional histologic variation within a malignant blue nevus, however, sampling error can cause delay in recognition of malignancy. A high clinical index of suspicion and appropriate biopsy technique are necessary to reach an early diagnosis. The most common site of metastasis of a malignant blue nevus is the lymph node. The phenomenon of benign lymph node nevus cell metastasis, which may occur with benign blue nevi, must be differentiated from a true malignant metastasis of a malignant blue nevus.

Aged↗
PubMed1988

The angiogenic properties of the rat vibrissa hair follicle associate with the bulb.

As the hair follicle is one of the most rapidly growing tissues in the body, it must be nourished by a rich blood supply. Histological studies have indicated that the number of vessels about a growing follicle exceeds that about a resting follicle, so we postulated that the hair follicle might provide its own angiogenic stimulus during certain phases of its growth. Reported here are experiments testing the angiogenic properties of the growing (anagen) hair follicle. Using the rabbit corneal pocket angiogenesis assay and cycled anagen rat vibrissae hair follicles, we found that the mesenchymal dermal papilla had no angiogenic properties, but the anagen bulb was angiogenic. These findings suggest a mechanism for the cycling of hair follicles and an example of normal epithelium to mesenchyme interactions.

Animals↗
PubMed1988

Proliferation of eccrine sweat ducts associated with alopecia areata.

Proliferation of sweat ducts has been described as a reactive process in a variety of benign and malignant neoplasms and inflammatory conditions in the skin, including scarring alopecia. However, to our knowledge this phenomenon has not been observed in non-scarring alopecia. The following case documents such a proliferation arising in an alopecia consistent with alopecia areata. An 83-year-old female developed progressive, fairly well circumscribed patches of alopecia over a 2-3 year period. Unequivocal scarring was not present. Histopathological examination revealed non-scarring alopecia with miniaturized and telogen follicles and a proliferation of eccrine ductal structures in the reticular dermis. These ductal structures varied in size and degree of cystic dilatation and resembled a primary eccrine neoplasm, such as syringoma. Only minimal focal fibrosis was observed in association with the eccrine proliferation. In summary, this case indicates that eccrine sweat duct proliferation may occur in non-scarring alopecia and must be differentiated from a primary eccrine neoplasm.

Aged↗
PubMed1988

Calcinosis cutis following extravasation of calcium chloride.

A 27-year-old woman with hypoparathyroidism developed multiple firm white-yellow papules along the path of an infiltrated calcium chloride intravenous infusion. A biopsy specimen obtained ten days after the extravasation revealed an urticarial reaction. A subsequent biopsy specimen, obtained 25 days after the extravasation, showed diffuse dermal calcification, confirmed by roentgenographic analysis, with incipient transepidermal elimination. A biopsy specimen obtained 40 days after the extravasation was consistent with an elimination reaction. An increase in mast cells was not noted. Electron microscopy showed mineral deposits along collagen fibrils without significant collagenous degeneration. In this report we describe a complication of intravenous calcium chloride infusion.

Adult↗
PubMed1987

Transforming growth factors and histopathologic interpretation.

Transforming growth factors, a group of small proteins that, under proper circumstances, induce the reversible morphologic transformation of mature cells, are produced by tumor cells and by stimulated differentiated cells. The pseudomalignant conditions that we recognize histologically may, in many instances, be explained by the action of these molecules.

Cell Differentiation↗
PubMed1987

Histological phases of Bactrim-induced fixed drug eruption. The report of one case.

A case is described of a patient with Bactrim-induced fixed drug eruption (FDE). Histological studies were performed at 1 day and 5 days after the drug exposure. While the 5-day-old lesion showed changes classically recognized as FDE, the 1-day-old lesion showed changes typical of a hypersensitivity response: diffuse spongiosis, dermal edema and hemorrhage, neutrophilic polymorphonuclear leukocyte abscess formations, and large numbers of eosinophils. This report underscores the dynamic cellular changes that occur in the evolving FDE lesion.

Aged↗
PubMed1987

Coepibolin, the activity of human serum that enhances the cell spreading properties of epibolin, associates with albumin.

Earlier studies have shown that epibolin, a glycoprotein in human plasma, identical to preparations from other laboratories referred to as serum spreading factor and vitronectin, requires a second plasma activity in order to support maximal primary epidermal cell spreading. This plasma fraction, referred to as coepibolin, alone supports no cell spreading but potentiates the activity of epibolin by at least 5-10 times. Studies reported here indicate that coepibolin activity associates with one plasma fraction, it cannot be substituted by commercial preparations of ovalbumin, soybean trypsin inhibitor, or hemoglobin, but it can be substituted by commercial bovine or human serum albumin. The activity purified to electrophoretic homogeneity comigrates with, and shows antigenic properties of albumin. Under the assay conditions coepibolin affects the extent and morphology of cell spreading: in the presence of epibolin plus coepibolin cells assume a more polar orientation than in epibolin alone. For its maximal effect coepibolin must be present continuously in the early phases of cell spreading.

Alkalies↗
PubMed1986

Cation dependence of guinea pig epidermal cell spreading.

To understand the earliest phases of epidermal cell spreading we have sought a defined in vitro system. We studied the divalent cation dependence of guinea pig epidermal cell spreading in media containing varying concentrations of cations. No spreading occurred in calcium-magnesium-free Dulbecco's modified Eagle's medium (CMF-DME) in the presence of cation-free fetal bovine serum; however, significant spreading occurred if the medium was supplemented with Mg++ plus Ca++ or Mg++ alone. Supplementing with Ca++ alone led to much less spreading. These cations in CMF-DME did not support spreading in the absence of serum or the presence of serum albumin. Assaying cell spreading in a simple salt solution consisting of NaCl, KCl, Tris buffer, pH 7.4 plus dialyzed serum and a series of divalent cation supplements (Ca++, Mg++, Mn++, Co++, Zn++, Ni++), showed that only Mg++ and Mn++, and to a lesser extent, Ca++, supported cell spreading. In contrast to Mg++, however, Mn++ could support spreading in the absence of whole serum if serum albumin were present. Although Mn++ plus serum albumin supported more rapid spreading at lower cation concentrations than Mg++ plus serum, equal concentrations of Ca++ completely blocked the Mn++ effect. In contrast to the increasing cell spreading, which occurred in Mg++-containing medium with time, cell death occurred in Mn++-containing medium by 24 h. Consonant with studies from other laboratories, human foreskin fibroblasts spread in Mn++-containing salt solution in the absence of protein supplements. These experiments indicate for epidermal cell spreading that Mg++ is the important cation in tissue culture media, that under proper cation conditions epidermal cells do not need a specific spreading protein (i.e. a protein that has been demonstrated to support cell spreading), that Mn++ and Mg++-induced spreading seem to represent different mechanisms, that fibroblastic and epidermal cells have different cation requirements for in vitro spreading, and that the crucial role cations play in cell spreading remains to be elucidated.

Animals↗
PubMed1986

Phorbol ester serves as a coepibolin in the spreading of primary guinea pig epidermal cells.

In earlier studies, it was shown that the human plasma-spreading glycoprotein, epibolin (the 65 kD species of serum-spreading factor or vitronectin), requires a second plasma component, termed coepibolin, in order to support maximal dissociated epidermal cell spreading in tissue culture. Whereas epibolin alone in defined medium supports some cell spreading, the purified plasma coepibolin preparations do not effect spreading in the absence of epibolin. Although not yet entirely purified, coepibolin associates with some plasma fractions but not with others; it is certainly not a property of all proteins, e.g., while bovine serum albumin (BSA) has coepibolin activity, ovalbumin does not. The data presented here show that the phorbol ester, 12-tetra-decanoyl-1-phorbol-13-acetate (TPA) can act as a potent coepibolin and support maximal spreading over a concentration range of 10-100 ng/ml. In the absence of epibolin TPA does not stimulate the spreading of epidermal cells when given alone or in the presence of BSA or ovalbumin. Coepibolin activity appears to associate with tumor-promoting activity in that the phorbol derivative, phorbol-12,13-didecanoate, shows coepibolin activity, while its inactive non-tumor-promoting isomer, phorbol-4 alpha-phorbol-12,13-didecanoate, does not. These data suggest that the proteinaceous plasma-derived cofactor acts in a fashion similar to TPA and that this as yet unexplained mechanism of TPA action is important to the full expression of epibolin and to the early phase of epidermal cell spreading.

Animals↗
PubMed1985

Liquid covering for superficial skin wounds and its effect on wound closure in guinea pigs.

An irrigatable bandage has been developed to hold fluid over a wound. Starting with superficial skin wounds on the back of guinea pigs, the bandage has been used to hold saline or phosphate-buffered saline containing antibiotics over the wound for up to 48 hours. Animals tolerated the bandage well for this period and bacterial contamination and wound maceration were not complications. The extent of reepithelialization with time was measured histologically under three separate conditions: wound exposed to air, wound covered and kept moist, and wound covered with liquid. By 24 hours 2 +/- 1%, 16 +/- 4% and 60 +/- 8% of the wound surface interfollicular areas showed some reepithelialization, respectively. On the average, at the same time these areas showed 15 +/- 2%, 19 +/- 2% and 37 +/- 1% coverage by epithelium. By these measurements, the liquid cover enhanced the rate of wound closure significantly.

Air↗
PubMed1984

Regressing atypical histiocytosis. Report of a case.

A patient with a pseudomalignant, histiocytic dermal lesion is reported. Despite a torpid course, the lesion was considered on histologic grounds by several consultants to be malignant. It appears to be distinct from previously reported pseudosarcomas or pseudolymphomas and most closely resembles a recently described condition termed "regressing atypical histiocytosis." The clinical and histopathologic features are summarized.

Histiocytes↗
PubMed1984

Epidermal cell confluence and implications for a two-step mechanism of wound closure.

In contrast to freshly isolated cells, some cultured keratinocytes have the ability to adhere and spread in protein-free media. Reported here are experiments testing the hypothesis that the social history of keratinocytes influences their ability to spread in defined media. The experiments indicate that confluent cells lack the ability to spread in defined media while subconfluent cells have this property. The inability of dissociated confluent cells to spread in protein-free media is referred to phenomenologically as a "confluent block." The confluent block is acquired rapidly (1-3 days) and lost slowly (5-7 days). The ability of subconfluent cells to spread in the absence of media protein is sensitive to cycloheximide. Aortic endothelial cells and dermal fibroblasts do not demonstrate a confluent block. These observations are consonant with a two-step mechanism of epidermal wound repair: the first occurs immediately after wounding during which the cells require substratum-active proteins, and the second occurs 5-7 days later when the cells are able to synthesize their own substratum.

Aorta↗