The effect of urea and taurine as hydrophilic penetration enhancers on stratum corneum lipid models.

To optimize transdermal application of drugs, the barrier function of the skin, especially the stratum corneum (SC), needs to be reduced reversibly. For this purpose, penetration enhancers like urea or taurine are applied. Until now, it is unclear if this penetration enhancement is caused by an interaction with the SC lipid matrix or related to effects within the corneocytes. Therefore, the effects of both hydrophilic enhancers on SC models with different dimensionality, ranging from monolayers to multilayers, have been investigated in this study. Many sophisticated methods were applied to ascertain the mode of action of both substances on a molecular scale. The experiments reveal that there is no specific interaction when 10% urea or 5% taurine solutions are added to the SC model systems. No additional water uptake in the head group region and no decrease of the lipid chain packing density have been observed. Consequently, we suppose that the penetration enhancing effect of both substances might be based on the introduction of large amounts of water into the corneocytes, caused by the enormous water binding capacity of urea and a resulting osmotic pressure in case of taurine.

Computational design of protein antigens that interact with the CDR H3 loop of HIV broadly neutralizing antibody 2F5.

Rational design of proteins with novel binding specificities and increased affinity is one of the major goals of computational protein design. Epitope-scaffolds are a new class of antigens engineered by transplanting viral epitopes of predefined structure to protein scaffolds, or by building protein scaffolds around such epitopes. Epitope-scaffolds are of interest as vaccine components to attempt to elicit neutralizing antibodies targeting the specified epitope. In this study we developed a new computational protocol, MultiGraft Interface, that transplants epitopes but also designs additional scaffold features outside the epitope to enhance antibody-binding specificity and potentially influence the specificity of elicited antibodies. We employed MultiGraft Interface to engineer novel epitope-scaffolds that display the known epitope of human immunodeficiency virus 1 (HIV-1) neutralizing antibody 2F5 and that also interact with the functionally important CDR H3 antibody loop. MultiGraft Interface generated an epitope-scaffold that bound 2F5 with subnanomolar affinity (K(D) = 400 pM) and that interacted with the antibody CDR H3 loop through computationally designed contacts. Substantial structural modifications were necessary to engineer this antigen, with the 2F5 epitope replacing a helix in the native scaffold and with 15% of the native scaffold sequence being modified in the design stage. This epitope-scaffold represents a successful example of rational protein backbone engineering and protein-protein interface design and could prove useful in the field of HIV vaccine design. MultiGraft Interface can be generally applied to engineer novel binding partners with altered specificity and optimized affinity.

From the structure of the skin barrier and dermal formulations to in vitro transport models for skin absorption: skin research in the Netherlands and in Germany.

This review presents an overview of German and Dutch research institutions and their studies in the field of skin drug delivery and adjacent topics. In the Netherlands, the involved research groups are mainly localized in Leiden, whereas in Germany the skin research institutions are spread over the whole country. The scientific studies in the Netherlands focus on the in-depth analysis of human skin composition and its individual components as well as on the development and characterization of dermal drug delivery systems ranging from liquid crystalline systems and vesicles up to microneedles with an emphasis on examining the interactions of these drug delivery systems with the human skin in vitro and in vivo. In Germany, the individual areas of research span from in-depth investigations on various drug delivery systems intended for skin application and the development of novel in vitro models for skin absorption testing up to in vivo studies focusing on the biological performance of topically applied actives. Furthermore, sophisticated analytical techniques are applied for the elucidation of skin assembly and transport processes. In addition, experimentally derived data are correlated with advanced computational modelling. Even though the individual research topics in the Netherlands and Germany are quite diverse, the exchange of knowledge and interdisciplinary collaborations between the two neighbouring countries were and are still frequently made. In this context, the review aims at highlighting crosslinks between the different institutions and individual persons to complete the picture. For each institution, the principal investigators and their studies are presented and the upcoming young scientists are introduced as an outlook for the field. This review does not claim completeness, but is rather intended to give a general overview of Dutch and German research in the field of skin drug delivery and adjacent topics.

Virulence and resistance determinants of German Staphylococcus aureus ST398 isolates from nonhuman sources.

A series of 100 Staphylococcus aureus isolates ascribed to sequence type 398 (ST398) and recovered from different sources (healthy carrier and diseased pigs, dust from pig farms, milk, and meat) in Germany were investigated for their virulence and antimicrobial resistance genetic background. Antimicrobial resistance was determined by the disk diffusion method. Virulence and resistance determinants (37 and 31 genes, respectively) were tested by PCR. Only two virulence profiles, including the accessory gene regulator agrI and three or four hemolysin-encoding genes, were detected. In contrast, 33 resistance profiles were distinguished (only 11 were shown by more than one isolate). Fifty-nine isolates were multiresistant (four or more antimicrobial classes), and 98 were methicillin resistant (mecA positive). All of the ST398 isolates showed resistance to tetracycline [encoded by tet(M) alone or together with tet(K) and/or tet(L)]. In addition, 98% were resistant to other antimicrobials, including macrolide-lincosamine-streptogramin B (70%, encoded by ermA, ermB, and ermC, alone or in combination), trimethoprim (65%, mostly due to dfrK and dfrG), kanamycin and gentamicin [29% and 14%, respectively, mainly related to aac(6')-Ie-aph(2″)-Ia and/or ant(4')-Ia but also to aph(3')-IIIa], chloramphenicol (9%, fexA or cfr), quinupristin-dalfopristin (9%), ciprofloxacin (8%), and trimethoprim-sulfamethoxazole (4%). The heterogeneity of the resistance profiles underlines the ability of the ST398 clone to acquire multiple antimicrobial resistance genes. However, the virulence gene content of the tested isolates was low. Continuous surveillance is needed to clarify whether its pathogenicity potential for animals and humans will increase over time.

High heterogeneity within methicillin-resistant Staphylococcus aureus ST398 isolates, defined by Cfr9I macrorestriction-pulsed-field gel electrophoresis profiles and spa and SCCmec types.

During recent years, the animal-associated methicillin-resistant Staphylococcus aureus clone ST398 has extensively been studied. The DNA of these isolates turned out to be refractory to SmaI restriction, and consequently, SmaI is unsuitable for subtyping this clone by standard pulsed-field gel electrophoresis (PFGE). Very recently, ST398 DNA was shown to be digested by Cfr9I, a neoschizomer of SmaI. In the present study, we employed Cfr9I PFGE on 100 German and 5 Dutch ST398 isolates and compared their PFGE profiles, protein A gene variable repeat regions (spa types), and types of the staphylococcal cassette chromosome mec (SCCmec). The isolates (from healthy carrier pigs, clinical samples from pigs, dust from farms, milk, and meat) were assigned to 35 profiles, which were correlated to the SCCmec type. A dendrogram with the Cfr9I patterns assigned all profiles to two clusters. Cluster A grouped nearly all isolates with SCCmec type V, and cluster B comprised all SCCmec type IVa and V* (a type V variant first identified as III) carriers plus one isolate with SCCmec type V. Both clusters also grouped methicillin-susceptible S. aureus isolates. The association of the majority of isolates with SCCmec type V in one large cluster indicated the presence of a successful subclone within the clonal complex CC398 from pigs, which has diversified. In general, the combination of Cfr9I PFGE with spa and SCCmec typing demonstrated the heterogeneity of the series analyzed and can be further used for outbreak investigations and traceability studies of the MRSA ST398 emerging clone.

Antibiotic resistance in Salmonella isolates from imported chicken carcasses in Bhutan and from pig carcasses in Vietnam.

The antibiotic resistance in Salmonella isolates from 400 imported chicken carcasses in Bhutan and from 178 pig carcasses in Vietnam were analyzed on a random basis against 14 antimicrobial agents. Among the poultry samples tested, 13% were positive for Salmonella. Salmonella Enteritidis dominated with a prevalence of 80.7%, and 40 of the 42 isolates harbored two or more resistance determinants. For the 178 pigs investigated, 49.4% of the swabs and 34.8% of the lymph nodes were Salmonella positive. The most prevalent serotypes in lymph nodes were Salmonella Derby (50.0%) and Salmonella Typhimurium (27.4%). From the Salmonella isolates from pigs, only 6% were sensitive to the antimicrobial agents tested. The high resistance level of Salmonella isolates from pigs and chicken carcasses to different classes of antimicrobials should be emphasized and encourage a prudent use of these agents in animal farming, especially in pig production.

Prevalence of MRSA types in slaughter pigs in different German abattoirs.

To investigate the prevalence of types of meticillin-resistant Staphylococcus aureus (MRSA) in slaughter pigs in German abattoirs, nasal swabs were collected from a total of 1026 pigs in five abattoirs after stunning in the course of two studies, and examined for MRSA. Study 1 included four abattoirs; study 2 was carried out in one large abattoir. Isolates were tested for antimicrobial susceptibility and characterised using spa-typing, multilocus sequence typing (MLST) and typing of the staphylococcal cassette chromosome, SCCmec. Overall, MRSA was isolated from 70.8 per cent of 520 samples in study 1 and from 49.0 per cent of 506 samples in study 2. The proportion of positive samples varied substantially between the abattoirs in study 1. Most isolates belonged to spa-types t011 and t034 and SCCmec types III and V. MLST of selected isolates revealed that they were all MLST ST398. Besides beta-lactams, 100 per cent of the isolates were resistant to tetracycline, 80.5 per cent were resistant to erythromycin and 80.7 per cent were resistant to clindamycin. Less than 5 per cent of the isolates were resistant to other antimicrobials.

Increasing isoflurane dose reduces homotopic correlation and functional segregation of brain networks in mice as revealed by resting-state fMRI.

Effects of anesthetics on brain functional networks are not fully understood. In this work, we investigated functional brain networks derived from resting-state fMRI data obtained under different doses of isoflurane in mice using stationary and dynamic functional connectivity (dFC) analysis. Stationary network analysis using FSL Nets revealed a modular structure of functional networks, which could be segregated into a lateral cortical, an associative cortical network, elements of the prefrontal network, a subcortical network, and a thalamic network. Increasing isoflurane dose led to a loss of functional connectivity between the bilateral cortical regions. In addition, dFC analysis revealed a dominance of dynamic functional states (dFS) exhibiting modular structure in mice anesthetized with a low dose of isoflurane, while at high isoflurane levels dFS showing widespread unstructured correlation displayed highest weights. This indicates that spatial segregation across brain functional networks is lost with increasing dose of the anesthetic drug used. To what extent this indicates a state of deep anesthesia remains to be shown. Combining the results of stationary and dynamic FC analysis indicates that increasing isoflurane levels leads to loss of modular network organization, which includes loss of the strong bilateral interactions between homotopic brain areas.

The late phase of the immediate wheal and flare skin reaction. Its dependence upon IgE antibodies.

IgE antibodies are usually thought to induce only immediate skin reactions. We have shown that the intradermal injection of a number of different allergens can produce a prolonged inflammatory reaction after the immediate wheal and flare in most sensitive subjects. This late inflammatory response occurs 6-12 h after challenge and is characterized by diffuse edema, erythema, pruritus, and heat. Both immediate and late responses can also be seen after passive sensitization of skin sites in nonatopic subjects. That IgE is involved in inducing the reaction was shown by the abolition of both immediate and late responses by passive transfer tests in the following experiments: (a) heating atopic serum at 56degreesC for 4 h, (b) removing IgE from the atopic serum by a solid phase anti-IgE immunoabsorbent, and (c) competitively inhibiting the binding of IgE antibodies to cells by an IgE myeloma protein. In addition, both responses were induced by affinity chromatography-purified IgE antibody, followed by antigenic challenge. Very similar lesions could also be induced by intradermal injection of Compound 48/80, thus suggesting a central role in the reaction for the mast cell or basophil. Histologically, the late phase is characterized by edema and a mixed cellular infiltration, predominantly lymphocytic but also containing eosinophils, neutrophils and basophils. Direct immunofluorescent staining did not show deposition of immunoglobulins or complement components, except IgM in 2 of 15 and C3 in 1 of 15 patients. This finding indicates that the late phase does not depend on the deposition of immune complexes. The results of the study suggest that IgE-allergen interaction on the surfaces of mast cells or on infiltrating basophils causes both immediate and late cutaneous responses.

Tests for treponemal antibody in CSF.

We studied the potential usefulness of CSF treponemal tests in the diagnosis of neurosyphillis. The CSF was tested with the microhemagglutination test for Treponema pallidum (CSF-MHA-TP test) and with the CSF-FTA test by using undiluted CSF and CSF diluted in saline and in sorbent. In a prospective evaluation, of 177 nonsyphilitics, none had reactive CSF-MHA-TP tests and only one had a reactive CSF-FTA test. However, five of 15 syphilitics with no other evidence of neurosyphilis had reactive CSF-FTA tests. The CSF-FTA test reactivity appeared most likely when the titer of the serum FTA test was high. In a retrospective evaluation of syphilitics with reactive CSF-FTA tests, similar patterns of reactivity occurred in patients with and without other evidence of neurosyphilis. Without other supporting clinical or laboratory data, the diagnostic value of a reactive CSF-FTA test is unknown.

C3b receptor in normal human skin.

Receptors for C3b in normal skin were studied. C3b was produced by treating normal human serum with cobra venom factor and by partial digestion of purified C3 with trypsin. Cryostat sections of normal human skin were incubated with C3b, followed by a direct immunofluorescent technique using monospecific goat antihuman C3. The histologic localization of C3b fluorescence was ascertained by fixing cryostat sections with glutaraldehyde and staining with hematoxylin and eosin. The following structures showed staining with anti-C3: (1) endothelial cells in capillaries, larger vessels, and arteries, (2) smooth muscle in arrector pilori muscles and artery walls, and (3) myoepithelial cells in the secretory portion of sweat glands. C3b did not bind to the intercellular substance nor to the basement membrane zone in normal human skin. Normal human sera treated with EDTA, EGTA, and heat (56 degrees C for 30 min) were negative, as was purified C3 by itself, thus indicating that native C3 did not bind to these receptors. Specificity for C3/C3b was shown by blocking with both unconjugated rabbit antihuman C3 and purified C3. The endothelial C3b receptor may have an important role in the localization of immune complexes in cutaneous vasculitis.

Characterization of the glucocorticoid receptor in human skin.

Because of the profound importance glucocorticoids have in dermatologic therapy, we studied the glucocorticoid receptor in human skin. A cytosol fraction was prepared from frozen skin by homogenization and centrifugation. When reacted with [3H]dexamethasone, this cytosol contained saturable, low-capacity binding. The glucocorticoid binding was stabilized by a protease inhibitor, phenylmethylsulfonylfluoride, and by sodium molybdate and was destroyed by trypsin. Sedimentation analysis of the glucocorticoid binding protein showed an 8S to 4S transition in high salt, a property of many known steroid hormone receptors. The binding was steroid specific, supporting the conclusion that this binding protein was a glucocorticoid receptor. The receptor molecule had a frictional ratio of 1.60 and a Mr of about 226,000 under low-salt conditions (0.05 M KCl) and a frictional ratio of 1.86 and a Mr of about 100,000 under high-salt conditions (0.3 M KCl) consistent with a nonglobular, elongated molecule. Isoelectric focusing showed that the receptor had 2 molecular species with isoelectric points of approximately 5.8 and 7.5. Quantitation of receptor in human skin showed 4-7 times more receptors in the epidermis and papillary dermis than in the lower dermis and nearly equal numbers in epidermis and papillary dermis. The concentration of receptors varied in different anatomic areas, with male foreskin showing the highest concentration, followed by female face, breast, and abdominal skin. Interestingly, the concentration of glucocorticoid receptors also varied with age; the highest levels were present at the extremes of life and a significantly lower level at midlife.

Localization of eosinophil granule major basic protein in chronic urticaria.

The role of the eosinophil in the pathogenesis of cutaneous diseases is not known. The eosinophil granule major basic protein (MBP), constituting the core and accounting for greater than 50% of the eosinophil granule, is toxic to helminths and mammalian cells. To determine whether eosinophil degranulation occurs in lesions of chronic urticaria, we performed an indirect immunofluorescence assay on sections of formalin-fixed, paraffin-embedded tissue, utilizing affinity chromatography-purified antibody to MBP. Twelve of 28 biopsies showed evidence of degranulation as judged by the deposition of MBP outside the eosinophil. The positive staining was of 3 types: (1) small blood vessel walls (5 patients), (2) dispersion of granular material (9 patients), and (3) focal or diffuse immunofluorescence of connective tissue fibers (11 patients). These results suggest a possible role for the cytotoxic molecule MBP in the evolution of lesions of chronic urticaria.

Whole organisms and purified cell walls compared as immunosorbents for the detection of IgE antibodies to Staphylococcus aureus.

We have developed an immunoradiometric assay for IgE antibodies to Staphylococcus aureus (Staph IgE-Ab) which uses purified cell walls (PCW) from the Wood 46 strain of S. aureus as an immunosorbent. We compared Wood 46 PCW and whole organisms (WO) as immunosorbents for Staph IgE-Ab by performing tests on sera from patients with atopic dermatitis (AD) or the hyperimmunoglobulin E syndrome (hyper IgE syndrome). Sera with Staph IgE-Ab demonstrated dose-dependent binding to PCW and WO, but the ratio of specific to non-specific binding was much greater with PCW. Mean non-specific binding to WO was greater than to PCW, 5% versus 2%; and non-specific binding to WO varied directly with the serum concentration of IgE. Results of tests on patients' sera indicated that PCW are required in screening assays for Staph IgE-Ab to avoid false positive results caused by high levels of non-specific binding to WO.

Acquired immunodeficiency syndrome-related Kaposi's sarcoma.

OBJECTIVE: To describe Kaposi's sarcoma (KS) associated with the acquired immunodeficiency syndrome (AIDS). DESIGN: A review of AIDS-related KS (AIDS-KS), with its associated epidemiologic and etiologic characteristics, pathogenesis, clinical manifestations, histopathologic features, prognosis, and treatment, is presented. RESULTS: KS is the most frequent malignant lesion in patients with AIDS. The incidence of AIDS-KS is high in homosexual and bisexual men who have multiple sexual partners and in children and women with the human immunodeficiency virus (HIV) infection. Anal-oral contact is one of the main routes of the sexually transmitted agents of AIDS-KS. The major pathogenic factors that may possibly induce AIDS-KS are HIV itself or other sexually transmitted agents, HIV tat gene, some oncogenes and cytokines such as interleukin 6, basic fibroblast growth factor, transforming growth factor-beta, oncostatin M, and platelet-derived growth factor. Treatment includes local therapy, radiotherapy, systemic chemotherapy, zidovudine, interferon, granulocyte-macrophage colony-stimulating factor, and other agents. CONCLUSION: KS may be an early manifestation of AIDS and the most frequent neoplastic complication of AIDS. Growth factors, cytokines, immunosuppression, and interaction with infectious agents seem to have a role in the development of this enigmatic disorder. Treatment of KS should be individualized. Further investigation of the agents and factors of AIDS-KS may help facilitate the treatment and prevention of this neoplasm.

Skin fibrinolytic activity in cutaneous and systemic vasculitis.

Study of involved and uninvolved skin from patients with necrotizing vasculitis revealed diminished tissue fibrinolytic activity deposition of immunoreactants in involved skin. In these patients, the depletion of tissue fibrinolytic activity is probably the result of vessel injury secondary to the local deposit of immunoreactants. In addition, there was diminished tissue fibrinolytic activity in uninvolved skin from patients with and without clinical skin involvement, unassociated with the deposition of immunoreactants. The precise mechanism for diminished tissue lytic activity in these latter patients is not known, but it may be associated with generalized activation of the coagulation and fibrinolytic mechanisms that result in local depletion of tissue fibrinolytic activity. These local changes may aggravate the clinical course of the disease as well as inhibit the healing of the lesions.

Immunologic mechanisms in systemic vasculitis.

Thirty-four patients with systemic vasculitis were studied to determine the possible type and frequency of associated immunologic abnormalities. The patients were divided into three clinical groups--those with systemic vasculitis without respiratory tract involvement, those with systemic vasculitis with respiratory tract involvement (particularly Churg-Strauss vasculitis and Wegener's granulomatosis), and those with limited vasculitis without visceral involvement. A diminished level of serum complement was found in half the patients with systemic vasculitis without respiratory tract involvement. These patients usually had diffuse skin disease that often was associated with the presence of rheumatoid factor and cryoglobulinemia and most likely represented an immune-complex induced disease. The serum IgE often was elevated in patients who had systemic vasculitis with respiratory tract involvement, particularly those with Churg-Strauss vasculitis and Wegener's granulomatosis, and may be a clue to the pathogenesis in this group of patients.

Hypocomplementemic urticarial vasculitis: association with chronic obstructive pulmonary disease.

Since 1973, we have identified and collected follow-up data on 16 patients with hypocomplementemic urticarial vasculitis. Preliminary diagnostic criteria are the presence of typical urticarial skin lesions and low levels of serum complement (all components), plus two of the following: dermal venulitis, arthritis, glomerulo-nephritis, episcleritis or uveitis, recurrent abdominal pain, and C1q precipitin in plasma. Exclusions are systemic lupus erythematosus, mixed cryoglobulinemia, elevated antinuclear antibody titer, hereditary deficiency of a complement component or of C1 esterase inhibitor, and presence of anti-native DNA or hepatitis B antigen. The renal involvement is relatively benign, and generally the patients do well and respond to specific treatment when this is indicated. Eight of 10 smokers studied had evidence of chronic obstructive pulmonary disease, 1 of whom died of this complication. In three patients, severe chronic obstructive pulmonary disease developed at a young age after relatively low pack-year cigarette smoking histories. Lung disease probably results from the interaction of two major risk factors-smoking and an immunologically mediated process that has not been identified.

The anticentromere antibody: disease specificity and clinical significance.

Serum samples from 539 subjects were screened for the presence of the anticentromere antibody on a human laryngeal carcinoma (HEp-2) cell line (Antibodies, Inc.). The antibody was present in 61 patients (11%), most of whom had features of limited scleroderma or the CREST syndrome (calcinosis cutis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia), either independently or in association with primary biliary cirrhosis. The antibody was rarely found in patients with rapidly advancing or diffuse scleroderma. The anticentromere antibody is therefore a useful prognostic indicator in patients with early scleroderma, as it may help to predict what pattern of scleroderma will evolve. Screening for this antibody should be conducted in all patients with Raynaud's phenomenon, primary biliary cirrhosis, and scleroderma. Other previous studies have indicated a similar disease specificity and prognostic importance of this antibody.

Cyclosporine in the treatment of dermatologic disease: an update.

Treatment with cyclosporine is beneficial for many dermatologic diseases such as psoriasis, lichen planus, Behçet disease, atopic dermatitis, pyoderma gangrenosum, and epidermolysis bullosa acquisita. The selective action of cyclosporine on helper T cells and its rapid therapeutic action and weak myelotoxicity are the key advantages in the treatment of many dermatologic diseases. Nevertheless, drug toxicity, especially nephrotoxicity, high rates of relapse after treatment cessation, and high cost have limited its use to those diseases refractory to other therapies. Herein we discuss the use of cyclosporine for dermatologic diseases relative to efficacy, dosage, safety profile, and monitoring. In addition, we review the formulations and metabolism of cyclosporine; discuss its mechanism of action, clinical indications in dermatology, and side effects; and provide usage guidelines for this drug. Cyclosporine can be safely administered when potential toxicities, dosing, and monitoring guidelines are known.