Novel proline substitution mutations in keratin 16 in two cases of pachyonychia congenita type 1

The peripheral benzodiazepine receptor (PBR) is a protein of mitochondrial outer membranes utilizing porphyrins as endogenous ligands. PBR is part of a heteromeric receptor complex involved in the formation of mitochondrial permeability transition pores and in the early events of apoptosis. PBR may function as an oxygen-dependent signal generator; recent data indicate that these receptors may preserve the mitochondria of haematopoietic cell lines from damage caused by oxygen radicals. To identify PBRs in human skin, we used a specific monoclonal antibody directed against the C-terminus fragment of the human receptor. PBR immunoreactivity was found in keratinocytes, Langerhans cells, hair follicles and dermal vascular endothelial cells. Interestingly, confocal microscopic examination of skin sections revealed that PBR expression was strongly upregulated in the superficial differentiated layers of the epidermis. Ultrastructurally, PBRs were distributed throughout the cytoplasm but were selectively expressed on the mitochondrial membranes of epidermal cells. The elevated level of PBRs in the spinous layer was not associated with an increased number of mitochondria nor with an increased amount of mRNA as assessed by in situ hybridization on microautoradiographed skin sections. The present work provides, for the first time, evidence of PBR immunoreactivity in human skin. This mitochondrial receptor may modulate apoptosis in the epidermis; its increased expression in differentiated epidermal layers may represent a novel mechanism of natural skin protection against free radical damage generated by ultraviolet exposure.     

Periderm cells form cornified cell envelope in their regression process during human epidermal development.

Terminally differentiated stratified squamous epithelium forms a lining of the plasma membrane called the cornified cell envelope, a thick layer of several covalently cross-linked precursor proteins including involucrin, small proline-rich proteins, and loricrin. Their cross-linking isodipeptide bonds are formed by epidermal transglutaminases 1-3. Material from lamellar granules is attached on the extracellular surface of corneocytes during the keratinization process. The formation of cornified cell envelope and sequential expression of major cornified cell envelope precursor proteins, transglutaminases, and 25 kDa lamellar granule-associated protein were studied in human embryonic and fetal skin. Ultrastructurally, membrane thickening has already started in periderm cells of the two-layered epidermis and an electron-dense, thickened cell envelope similar to cornified cell envelope in adult epidermis is observed in periderm cells at the three-layered and later stages of skin development. In the two-layered epidermis (49-65 d estimated gestational age), immunoreactivities of involucrin, small proline-rich proteins, all the transglutaminases, and lamellar granule-associated protein were present only in the periderm. In the three-layered epidermis and thereafter (66-160 d estimated gestational age), loricrin became positive in the periderm cells, transglutaminases extended to the entire epidermis, and lamellar granule-associated protein was detected in intermediate cells as well as periderm cells. Immunoelectron microscopy demonstrated that both major cornified cell envelope precursor proteins, involucrin and loricrin, were restricted to the cornified cell envelope in periderm cells at this stage of development. After 160 d estimated gestational age, the periderm had disappeared and cornified cell envelope proteins and lamellar granule-associated proteins were expressed in the spinous, granular, and cornified cells and transglutaminases were detected in the entire epidermis. These findings indicate that cornified cell envelope precursor proteins, transglutaminases, and lamellar granule-associated proteins are expressed in coordination in periderm cells during human epidermal development and suggest that periderm cells form cornified cell envelope in the process of regression.     

Differential virulence of herpes simplex virus intratypic strains

Many events determine the severity, duration, and predisposition to recurrent herpes simplex virus (HSV) disease. In addition to the various host immune responses, such as local, humoral, and cellular immunity, which influence the outcome of infection and subsequent development of disease, evidence is also accumulating to suggest that intratypic strains of HSV may also play an important role in the outcome, depending on the degree of virulence each strain exhibits. Since it has been suggested that each individual is initially infected and colonized with a strain of virus whose characteristic virulence or avirulence will determine the type of HSV disease that individual will experience, it is suggested that intratypic strains should be considered an important variable in recurrent HSV disease.     

Biochemical and ultrastructural processing of [125I]epidermal growth factor in rat epidermis and hair follicles: accumulation of nuclear label

Although the intracellular ultrastructural processing of epidermal growth factor (EGF) and its receptor have been described in cell culture systems, very few studies have examined this phenomenon in intact tissues. We have examined the ultrastructural and biochemical handling of [125I]EGF in the epidermis and hair follicle bulb of intact, viable, 3- to 5-day-old rat skin the EGF receptor distribution of which has already been documented and in which EGF has been shown to be biologically active. After incubation of explants with 10 nM [125I]EGF for 2.5 h at 25 degrees or 37 degrees C, radiolabel was detected over the basal cells of the epidermis and hair follicle outer root sheath, confirming previous light microscope observations. More specifically, silver grains were observed near coated and uncoated plasma membrane and coated membrane invaginations, Golgi apparatus, lysosomal structures, and nuclei. Sodium azide inhibited internalization of label, whereas a series of lysosomal inhibitors (chloroquine, monensin, and iodoacetamide) caused a slight increase in silver grains associated with lysosomal vesicles and a decrease in nuclear label. Biochemical analysis indicated that greater than 35% of radioactivity following incubation at 37 degrees C was in the form of degraded [125I]EGF fragments and that inclusion of chloroquine, monensin, and iodoacetamide reduced this value to 20.8%, 8.6%, and 4.0%, respectively. In addition, chloramine T-prepared [125I]EGF was found to be covalently cross-linked with low efficiency to a protein having the molecular weight of the EGF receptor. These data are discussed in the light of the effects of EGF on epithelial cell proliferation in skin.     

High prevalence of antibodies to herpes simplex virus type 2 among middle-aged women in Mexico City, Mexico: a population-based study

BACKGROUND: Herpes simplex virus type 2 (HSV-2) is among the most prevalent sexually transmitted diseases worldwide. In Mexico there is a lack of population-based HSV-2 surveys. GOALS: To determine population-based HSV-2 seroprevalence and risk factors among women in Mexico City. STUDY DESIGN: A random sample of 730 women was identified among the residents of Mexico City. Women ages 25 to 85 years were selected from 3,694 households. Western blot serology testing was conducted on serum samples to determine HSV-2 type-specific serostatus. A structured questionnaire was administered, and multivariate analyses were performed to identify risk factors for HSV-2 seropositivity, which were stratified into two age categories: younger than 50 years of age and 50 years of age or older. RESULTS: The HSV-2 seroprevalence among female participants was 29.8%, with a significant trend of increasing HSV-2 prevalence for each higher level of age (P < 0.001). Female participants had a median age of 46 years and were predominantly monogamous (82.6%). The overall population-based seroprevalence estimated in Mexico City among women was 35.8%. The independent risk factors for HSV-2 seropositivity included a history of two or more sexual partners (odds ratio [OR], 2.2; 95% CI, 1.4-3.4), two or more sexual partners before first pregnancy (OR, 2.3; 95% CI, 1.4-3.7), cohabitation with partner (OR, 2.5; 95% CI, 1.3-4.7), and current vaginal douching (OR, 1.7; 95% CI, 1.2-2.6). CONCLUSIONS: Population-based HSV-2 seroprevalence is endemically high among middle-age women in Mexico City, and clearly is correlated with higher-risk sexual behavior. This elevated HSV-2 seroprevalence may reflect unrecognized HSV-2 transmission throughout life.     

Neonatal lupus erythematosus: factors which may lead to clinical disease in the foetus even in the absence of disease in the mother

Neonatal lupus erythematosus (NLE) occurs in neonates of mothers who, in almost all cases, have auto-antibodies to the SSA/Ro associated proteins, but who may have no clinical disease. However, only a small percentage of mothers with SSA/Ro antibodies have affected babies, predisposing factors specific to the foetus or neonate (i.e. HLA pattern) and/or fetal maternal interactions have been proposed to be important. We present a mother with a family history of autoimmune disease, but without clinical disease, whose baby developed cutaneous NLE. Autoantibody determinations as well as the HLA-DR/DQ were performed in the mother and baby. Factors other than the HLA-DR/DQ status of the mother appear to be important in determining whether or not the neonate will develop NLE. Auto-antibodies to endogenous antigens common to the mother, transiently expressed developmental antigens, and the isotype specificity of transferred antibodies may be important in determining disease in the baby.     

Isolation and immunochemical characterization of the group-specific antigen of Streptococcus mutants 6715.

The group d antigen of Streptococcus mutans 6515 was isolated from a buffer (pH 7.3)-boiled extract of whole cells and analyzed immunochemically. Rabbits immunized in three different fashions with whole S. mutans 6715 each responded to the same antigenic cell surface component. This presumptive major antigen was found in culture supernatant, sonically treated supernatant, acid and buffer extracts of whole cells, and trichloroacetic acid extract of cell membranes. A crude preparation of this antigen could completely inhibit antibody-mediated cell (S. mutans 6715) agglutination in a spectrophotometric analysis. The antigen was purified from buffer-boiled extracts by gel filtration on columns of Sepharose 4B. The antigen did not migrate to the anode on electrophoresis nor did it contain appreciable quantities of phosphorus, glycerol, or ribitol. This suggested that the d antigenicity did not reside in a teichoic acid. The d antigen contained galactose and glucose as the sole saccharides, in a ratio of 5.9:1.0. Protein (9.5%) appeared to be a portion of the antigen, although Pronase-digested antigen retained the same electrophoretic mobility and could precipitate virtually all (98.6%) purified antibody directed to the intact antigen. The data obtained from hapten innvolved. Glucose also contributed to the immunodominant region. Antibody directed to the d antigen may be of importance in the inhibition of adherence phenomena manifested by S. mutans organisms of the d group.