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Biomedical subjects

H P Baden

Publications and source records attributed to H P Baden.

At least 19 recordsLinked to original sources
PubMed1992

Detection of substrates of keratinocyte transglutaminase in vitro and in vivo using a monoclonal antibody to dansylcadaverine.

A method providing more sensitive detection of transglutaminase substrates was developed to localize transglutaminase activity in tissue and to identify in vivo substrates in epidermal extracts. The enhanced sensitivity of this method was achieved via the generation of a monoclonal antibody (designated E7) made to dansylcadaverine. Transglutaminase substrates were visualized by western blot after a 1-min incubation with dansylcadaverine in contrast to the 2 h required when [14C]putrescine incorporation was measured by autoradiography of SDS-polyacrylamide gels. In addition, putative substrates not apparent using conventional methods were readily detected by western analysis. An ELISA assay to measure transglutaminase activity showed similar sensitivity to the traditional radiometric assay (Lorand et al., 1972). The correlation between the ELISA procedure and the radiometric assay was high (r2 = 0.924). Strips of neonatal human and mouse skin incubated in dansylcadaverine-supplemented culture medium were used to localize enzyme activity and to detect substrates in vivo. Transglutaminase activity was demonstrated at the cellular periphery in the upper spinous and granular cell layers of the epidermis. Substrates detected in epidermal extracts were similar to those detected using the in vitro assay. This technique allows for highly sensitive and nonradiometric analysis of both enzymatic activity and the substrates involved. The extension of this methodology to an in vivo system is the first demonstration of a system in which the dynamics of cornified envelope assembly may be further studied.

Animals↗
PubMed1992

Keratinocytes stimulate prostaglandin I2 synthesis by 3T3 cells and exhibit enhanced cornification when exposed to prostaglandin I2 analogues.

The predominant cyclooxygenase products of keratinocytes are prostaglandin (PG)E2 and PGF2 alpha with only trace amounts of PGI2 synthesis detected. When normal or immortal (NM1) keratinocytes were co-cultured with mitomycin C-treated 3T3 cells, increased synthesis of PGI2 was noted compared to mitomycin C-treated 3T3 cells alone. The PGI2 level in co-cultures was maximum within the first week and diminished rapidly thereafter. These results suggested keratinocytes enhance the production of PGI2 by 3T3 cells. Keratinocyte cultures incubated with Iloprost and Piriprost, stable PGI2 analogues, showed evidence of increased cornification as demonstrated by staining with rhodanile blue, decreased shedding of cells into the culture medium, and more cornified material adhering to the culture surface. The cultures appeared to be responsive between the first and second weeks after plating and the inhibition of shedding could not be reversed by changing to drug-free medium. Control and treated cultures showed identical electrophoretic protein patterns. Immunoblots showed involucrin unchanged in extracts of control and treated cultures while the 22 kd pancornulin was absent in treated cultures. The findings that keratinocytes enhance the production of PGI2 by 3T3 cells and that PGI2 analogues enhance cornification of confluent keratinocytes raise the possibility that eicosanoids may serve as autoregulatory signals together with other factors.

3T3 Cells↗
PubMed1992

Sodium stibogluconate (Pentostam) overdose during treatment of American cutaneous leishmaniasis.

A 27-year-old woman who acquired cutaneous leishmaniasis in Central America was inadvertently treated with 10 times the intended daily dose of the pentavalent antimonial compound sodium stibogluconate (Pentostam): 8500 mg (143 mg/kg) instead of 850 mg. The patient felt "wiped out" during the 4-h infusion of the drug. After the mistake in dosing was discovered, she was vigorously hydrated and carefully monitored in an intensive care unit for greater than 48 h. Her vital signs were stable, and no arrhythmias were noted. Her alanine aminotransferase level rose briefly to 2.4 times the upper limit of normal, and her white blood cell count briefly fell 43% to a low of 3700/microliter. Her skin lesions subsequently healed without further therapy. Although sodium stibogluconate has been associated with a variety of side effects, in this case, a single high dose of the drug was tolerated without serious toxicity.

Adult↗
PubMed1992

Proteins of the cornified envelope.

The cornified envelope of keratinocytes is an insoluble structure formed beneath the plasma membrane at the base of the stratum corneum. It is made by cross-linking precursor proteins by a membrane-associated transglutaminase. Using the cornified envelope of cultured human keratinocytes as the immunogen, we obtained a number of monoclonal antibodies which stained epidermis in a variety of ways. The peripheral staining pattern has been associated with several envelope precursors and this has been confirmed by western blots. A mouse IgM monoclonal antibody directed against epidermal basal cell hemidesmosomes was also discovered. By immunofluorescence, the monoclonal antibody produced a strong linear staining of the basement membrane zone and a polar cap on trypsin-dissociated epidermal basal cells. By immunoelectron microscopy, immunoreactants were present in the attachment plaques of hemidesmosomes on guinea pig esophagus. However, no protein reactive with the antibody was detected. This study suggests that an antigen associated with the basal cell hemidesmosomes may be incorporated in the cornified envelope.

Animals↗
PubMed1992

Characterization of sciellin, a precursor to the cornified envelope of human keratinocytes.

The cornified envelope, located beneath the plasma membrane of terminally differentiated keratinocytes, is formed as protein precursors are cross-linked by a membrane associated transglutaminase. This report characterizes a new precursor to the cornified envelope. A monoclonal antibody derived from mice immunized with cornified envelopes of human cultured keratinocytes stained the periphery of more differentiated cells in epidermis and other stratified squamous epithelia including hair and nails. The epitope was widely conserved among mammals as determined by immunohistochemical and Western analysis. Immunoelectron microscopy localized the epitope to the cell periphery in the upper stratum spinosum and granulosum of epidermis. In the hair follicle, the epitope was present in the internal root sheath and in the infundibulum, the innermost aspect of the external root sheath. The antibody recognized a protein of relative mobility (M(r)) 82,000, pI 7.8. The protein was a transglutaminase substrate as shown by a dansylcadaverine incorporation assay. Purified cornified envelopes absorbed the reactivity of the antibody to the partially purified protein and cleavage of envelopes by cyanogen bromide resulted in release of immunoreactive fragments. The protein was soluble only in denaturing buffers such as 8 M urea or 2% sodium dodecyl-sulfate (SDS). Partial solubility could be achieved in 50 mM TRIS pH 8.3 plus 0.3 M NaCl (high salt buffer); the presence of a reducing agent did not affect solubility. Extraction of cultured keratinocytes in 8 M urea and subsequent dialysis against 50 mM TRIS pH 8.3 buffer resulted in precipitation of the protein with the keratin filaments. Dialysis against high salt buffer prevented precipitation of the protein. The unique solubility properties of this protein suggest that it aggregates with itself and/or with keratin filaments. The possible role of the protein in cornified envelope assembly is discussed. We have named this protein Sciellin (from the old english "sciell" for shell).

Animals↗
PubMed1992

Loose anagen hair as a cause of hereditary hair loss in children.

BACKGROUND AND DESIGN: The loose anagen hair syndrome is a recently described disorder with enhanced hair loss in which anagen hairs can be painlessly pulled from the scalp. RESULTS: In three families, we have observed an autosomal dominant form of inheritance. We have confirmed that the extracted bulbs consist only of cortical cells and that the hair shafts have an abnormal shape. Using routine light and electron microscopy, we observed disadhesion between all layers of the follicle and within some layers and premature keratinization of the inner root sheath of the follicle. In addition, abnormal maturation of the various layers was observed at the electron microscopic level, including regions of the cortex that contained decreased numbers of filaments. The disorder appears to be cyclic, since relatively normal and markedly affected regions of the shaft can be observed within a single follicle. CONCLUSIONS: Possible mechanisms responsible for the disease include abnormal intercellular signaling and disturbances of desmosomal components and/or cadherins.

Alopecia↗
PubMed1991

A role for sunlight in skin cancer: UV-induced p53 mutations in squamous cell carcinoma.

Sunlight is a carcinogen to which everyone is exposed. Its UV component is the major epidemiologic risk factor for squamous cell carcinoma of the skin. Of the multiple steps in tumor progression, those that are sunlight-related would be revealed if they contained mutations specific to UV. In a series of New England and Swedish patients, we find that 14/24 (58%) of invasive squamous cell carcinomas of the skin contain mutations in the p53 tumor suppressor gene, each altering the amino acid sequence. Involvement of UV light in these p53 mutations is indicated by the presence in three of the tumors of a CC----TT double-base change, which is only known to be induced by UV. UV is also implicated by a UV-like occurrence of mutations exclusively at dipyrimidine sites, including a high frequency of C----T substitutions. p53 mutations in internal malignancies do not show these UV-specific mutations. The dipyrimidine specificity also implicates dipyrimidine photoproducts containing cytosine as oncogenic photoproducts. We believe these results identify a carcinogen-related step in a gene involved in the subsequent human cancer.

Aged↗
PubMed1991

Dietary management reverses grooving and abnormal polarization of hair shafts in argininosuccinase deficiency.

We have observed that the fragile hair of two untreated patients with argininosuccinic aciduria showed abnormal alternating zones of bright and dark banding by polarizing microscopy. Scanning electron microscopy documented discontinuous grooves with a 50 to 100 microns periodicity. Results of amino acid analysis of the hair were essentially normal. After the patients were treated with a low-protein, arginine-supplemented diet, the hair assumed a normal appearance. Five patients already treated with diet showed no hair abnormalities. The pathogenesis of the hair changes in unknown, but our findings suggest that products generated in the disease can adversely affect metabolically active tissue such as hair.

Amino Acid Metabolism, Inborn Errors↗
PubMed1991

Nail changes in cutaneous disease.

Nail involvement in cutaneous disease provides the clinician with diagnostic clues, and may be of great cosmetic significance to patients. Nail manifestations of the most common and/or important cutaneous diseases are discussed. Photographic illustrations of these changes are also presented.

Humans↗
PubMed1990

Yellow nail syndrome.

The yellow nail syndrome is characterized by yellow, slow-growing nails in association with lymphedema, idiopathic pleural effusions, chronic bronchiectasis, and chronic sinusitis. We report two patients with yellow nail syndrome in whom spontaneous clearing of the nail changes occurred without resolution of the respiratory involvement. This observation suggests that nail changes may not result from the systemic manifestations. We also report for the first time the histopathologic findings of the nail matrix and bed, which demonstrate dense, fibrous tissue replacing subungual stroma with numerous ectatic, endothelium-lined vessels that are similar to that in the pleura in yellow nail syndrome. We hypothesize that primary stromal sclerosis may lead to lymphatic obstruction, thus explaining the clinical manifestations.

Chronic Disease↗
PubMed1990

The pancornulins: a group of basic low molecular weight proteins in mammalian epidermis and epithelium that may function as cornified envelope precursors.

1. A monoclonal antibody (HCE-2) to human epidermal and epithelial cornified envelopes identified a group of soluble basic protein precursors. 2. Using HCE-2, envelope-like staining was observed in the epidermis and stratified squamous epithelium of a number of mammalian species. 3. Basic polypeptides reactive to HCE-2 varied in size and number among the different animals. 4. In those species studied, HCE-2-reactive peptides were substrates for transglutaminase and protease treatment of cornified envelopes released HCE-2-reactive degradation products. 5. These results suggest a new family of proteins in mammalian epidermis that may function as cornified envelope precursors.

Animals↗
PubMed1990

Involucrin-like proteins in non-primates.

A monoclonal and two polyclonal antibodies to human involucrin were used to look for involucrin epitopes in other species. All antibodies react strongly with the same proteins of monkey, and both polyclonal antibodies react with specific proteins of cow and dog. One of the polyclonal antibodies also reacts with proteins of sheep, guinea pig, rat, and finback whale. The immunoreactive proteins from cow and dog could be purified using a procedure developed for human involucrin. The reaction with the purified dog protein could be blocked by purified human involucrin. The results suggest that involucrin-like proteins have a wider species distribution than originally appreciated.

Animals↗
PubMed1990

An unusual cutaneous metastasis of a chondrosarcoma.

We report a case of cutaneous metastases from a scapular chondrosarcoma in a 85-year-old man. The metastatic skin lesion was noted nine years after resection of the primary tumor. Metastases to lung and soft tissues had occurred four years earlier. The patient also had a history of malignant melanoma. Although this case illustrates an unusual pattern of metastases, we conclude that the appearance of cutaneous lesions in a patient with a prior history of chondrosarcoma should alert the clinician to the possibility of a metastatic chondrosarcoma.

Aged↗
PubMed1989

Tufted hair folliculitis.

A case of scarring alopecia presenting as two circumscribed, tender and inflamed areas in the occiput with residual tufted follicles is reported. Each tuft comprised 10 to 15 normal-appearing hairs arising from individual hair follicles in the reticular dermis or subcutaneous fat, converging toward a single orifice in the epidermis. The initial pathologic finding was inflammation and scarring of the papillary and mid dermis with almost total sparing of the hair follicles in the subcutaneous fat. Successful treatment was achieved by surgical excision of the two areas. It is suggested that the areas of tufting represented nevoid lesions that underwent inflammation and scarring.

Adult↗