Congenital absence of dermatoglyphs.

Congenital absence or unusual patterns of human dermatoglyphs (fingerprints) occur in several syndromes that are rare and poorly understood. The abnormalities of dermatoglyphs fall into four categories: complete absence, ridge hypoplasia, ridge dissociation, and ridges-off-the-end. Complete congenital absence of ridges is an exceedingly rare syndrome that consists of neonatal blisters and milia, adult traumatic blistering and fissuring, absence of sweating, contracture of digits, and absence of dermatoglyphs on the hands and feet. The syndrome is inherited in an autosomal dominant pattern, and only two kindreds have been described in the literature. We describe a newly identified patient and kindred with findings similar to the previously reported cases and review the clinical and histopathologic findings of this syndrome.

Effect of inducers on the activity of glutathione S-transferase and other enzymes of the glutathione pathway in cultured human keratinocytes.

Known inducers of the hepatic glutathione (GSH) S-transferases were tested at the limits of their solubility as inducers of the enzyme in cultured human keratinocytes. Neither phenobarbital, trans-stilbene oxide, propylthiouracil, nor butylated hydroxyanisole increased GSH S-transferase activity or led to the appearance of alpha- or mu-forms of the enzyme, as judged by Western blotting. Only the pi-form of the enzyme was found before and after all treatments. Thus, the enzyme is not inducible in keratinocytes. However, 4 mM propylthiouracil did lead to a 50% increase in GSH reductase activity, and phenobarbital at 4 mM completely abolished GSH peroxidase and GSH reductase activity and led to a significant loss of viability.

Characterization of the oxidative stress initiated in cultured human keratinocytes by treatment with peroxides.

Cultured human keratinocytes were treated with H2O2, Fe++/Fe , H2O2 + Fe++/Fe , t-butylhydroperoxide (tBHP), or cumene hydroperoxide (CHP). Fe++ +/- Fe was without effect on cell viability. Neither CHP, tBHP, nor H2O2 at 200 microM led to alteration of trypan blue exclusion, but with 700 microM CHP or tBHP there was uptake of trypan blue after 20 min and lysis of cells beginning at 4 h of treatment. Lysis occurred even if the organic hydroperoxide was removed from the media after 1 h. Treatment with 700 microM H2O2 resulted in half of the cells becoming permeable to trypan blue by 60 min, but > 80% of the cells remained intact and functional, and eventually recovered their impermeability to trypan blue. No concentration of H2O2, tBHP, or CHP produced significant thiobarbituric acid (TBA)-reactive material, and Fe++/Fe , H2O2 + Fe++/Fe , and CHP + Fe++/Fe led to the formation of only small amounts of TBA-reactive material. This was attributed to a lack of polyunsaturated lipid in cells cultured in synthetic media. The activity of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is sensitive to oxidative damage and thus was used as an indicator of oxidative stress along with the ratio of reduced/oxidized glutathione (GSH/GSSG). Using these two criteria, we found that CHP or tBHP treatment led to an oxidative stress that was more protracted as compared with the effect of H2O2. The organic peroxides also led to depletion of total glutathione, an effect not found with H2O2. It was also found that H2O2 was more rapidly metabolized than the organic peroxides. In summary, cultured human keratinocytes treated with peroxides underwent a number of changes, which included inactivation of GAPDH, a decrease in the ratio GSH/GSSG, and a loss of trypan blue exclusion. However, as long as the duration of this oxidative stress was short, these changes were reversible and the cells survived. Prolonged oxidative stress led to irreversible damage and cell death. H2O2 was rapidly metabolized and relatively well tolerated by keratinocytes. On the other hand, organic hydroperoxides were metabolized more slowly and were lethal at sub-millimolar concentrations. The relative toxicity of organic hydroperoxides is hypothesized to be related to their non-polar nature.

Characterization of glutathione S-transferase in cultured human keratinocytes.

The glutathione S-transferase activity and isozymic composition of cultured human keratinocytes were characterized. Keratinocytes were grown in culture and harvested at different stages of differentiation. Glutathione S-transferase activity was found in the soluble cell fraction but not in the microsomal cell fraction. The glutathione S-transferase specific activity of the soluble cell fraction was found to increase as the keratinocytes differentiated in culture. All of the enzymatic activity was found to reside with a single isozymic form that was concluded to be the pi form of the enzyme based on substrate specificity, sensitivity to inhibitors, molecular weight, and reactivity towards antibodies raised to alpha, mu, and pi forms of the enzyme. It is concluded that all of the isozymic forms of glutathione S-transferase noted in whole skin, with the exception of pi, are of extra-keratinocyte origin.

Mitomycin C-treated 3T3 fibroblasts used as feeder layers for human keratinocyte culture retain the capacity to generate eicosanoids.

Murine 3T3 fibroblasts, treated with mitomycin C in order to inhibit their proliferation, have been extensively used as feeder layers to enhance the cultivation of human keratinocytes in vitro. In order to identify possible factors responsible for this enhancing effect, studies were undertaken to determine whether eicosanoid generation by 3T3 cells was preserved following mitomycin C treatment. Accordingly, both untreated and mitomycin C-treated 3T3 cells were incubated with [1-14C]arachidonic acid and their qualitative generation of [1-14C]labeled eicosanoids assessed by thin layer chromatography. Levels of endogenously generated eicosanoids were quantitatively determined by specific radioimmunoassays performed on culture supernatants obtained from incubations of both treated and untreated cells. Results of these studies demonstrate that mitomycin C treatment, although preventing the proliferation of 3T3 cells, failed to alter their generation of prostaglandin E2 or 6-keto-prostaglandin F1 alpha. Furthermore, in parallel cultures, the untreated 3T3 cells stopped generating eicosanoids upon reaching confluence, whereas the mitomycin C-treated 3T3 cells that did not proliferate continued to generate eicosanoids.