Ebolavirus Species-Specific Interferon Antagonism Mediated by VP24

Members of the Ebolavirus genus demonstrate a marked differences in pathogenicity in humans with Ebola (EBOV) being the most pathogenic, Bundibugyo (BDBV) less pathogenic, and Reston (RESTV) is not known to cause a disease in humans. The VP24 protein encoded by members of the Ebolavirus genus blocks type I interferon (IFN-I) signaling through interaction with host karyopherin alpha nuclear transporters, potentially contributing to virulence. Previously, we demonstrated that BDBV VP24 (bVP24) binds with lower affinities to karyopherin alpha proteins relative to EBOV VP24 (eVP24), and this correlated with a reduced inhibition in IFN-I signaling. We hypothesized that modification of eVP24-karyopherin alpha interface to make it similar to bVP24 would attenuate the ability to antagonize IFN-I response. We generated a panel of recombinant EBOVs containing single or combinations of point mutations in the eVP24-karyopherin alpha interface. Most of the viruses appeared to be attenuated in both IFN-I-competent 769-P and IFN-I-deficient Vero-E6 cells in the presence of IFNs. However, the R140A mutant grew at reduced levels even in the absence of IFNs in both cell lines, as well as in U3A STAT1 knockout cells. Both the R140A mutation and its combination with the N135A mutation greatly reduced the amounts of viral genomic RNA and mRNA suggesting that these mutations attenuate the virus in an IFN-I-independent attenuation. Additionally, we found that unlike eVP24, bVP24 does not inhibit interferon lambda 1 (IFN-λ1), interferon beta (IFN-β), and ISG15, which potentially explains the lower pathogenicity of BDBV relative to EBOV. Thus, the VP24 residues binding karyopherin alpha attenuates the virus by IFN-I-dependent and independent mechanisms.

Antiviral protection by antibodies targeting the glycan cap of Ebola virus glycoprotein requires activation of the complement system

Antibodies to Ebola virus glycoprotein (EBOV GP) represent an important correlate of the vaccine efficiency and infection survival. Both neutralization and some of the Fc-mediated effects are known to contribute the protection conferred by antibodies of various epitope specificities. At the same time, the role of the complement system in antibody-mediated protection remains unclear. In this study, we compared complement activation by two groups of representative monoclonal antibodies (mAbs) interacting with the glycan cap (GC) or the membrane-proximal external region (MPER) of the viral sole glycoprotein GP. Binding of GC-specific mAbs to GP induced complement-dependent cytotoxicity (CDC) in the GP-expressing cell line via C3 deposition on GP in contrast to MPER-specific mAbs that did not. Moreover, treatment of cells with a glycosylation inhibitor increased the CDC activity, suggesting that N-linked glycans downregulate CDC. In the mouse model of EBOV infection, depletion of the complement system by cobra venom factor led to an impairment of protection exerted by GC-specific but not MPER-specific mAbs. Our data suggest that activation of the complement system is an essential component of antiviral protection by antibodies targeting GC of EBOV GP.

Coronavirus Immunotherapeutic Consortium Database

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has seen multiple anti-SARS-CoV-2 antibodies being generated globally. It is difficult, however, to assemble a useful compendium of these biological properties if they are derived from experimental measurements performed at different sites under different experimental conditions. The Coronavirus Immunotherapeutic Consortium (COVIC) circumvents these issues by experimentally testing blinded antibodies side by side for several functional activities. To collect these data in a consistent fashion and make it publicly available, we established the COVIC database (COVIC-DB, https://covicdb.lji.org/). This database enables systematic analysis and interpretation of this large-scale dataset by providing a comprehensive view of various features such as affinity, neutralization, in vivo protection and effector functions for each antibody. Interactive graphs enable direct comparisons of antibodies based on select functional properties. We demonstrate how the COVIC-DB can be utilized to examine relationships among antibody features, thereby guiding the design of therapeutic antibody cocktails. Database URL  https://covicdb.lji.org/.

Epitope-focused immunogen design based on the ebolavirus glycoprotein HR2-MPER region

The three human pathogenic ebolaviruses: Zaire (EBOV), Bundibugyo (BDBV), and Sudan (SUDV) virus, cause severe disease with high fatality rates. Epitopes of ebolavirus glycoprotein (GP) recognized by antibodies with binding breadth for all three ebolaviruses are of major interest for rational vaccine design. In particular, the heptad repeat 2 -membrane-proximal external region (HR2-MPER) epitope is relatively conserved between EBOV, BDBV, and SUDV GP and targeted by human broadly-neutralizing antibodies. To study whether this epitope can serve as an immunogen for the elicitation of broadly-reactive antibody responses, protein design in Rosetta was employed to transplant the HR2-MPER epitope identified from a co-crystal structure with the known broadly-reactive monoclonal antibody (mAb) BDBV223 onto smaller scaffold proteins. From computational analysis, selected immunogen designs were produced as recombinant proteins and functionally validated, leading to the identification of a sterile alpha motif (SAM) domain displaying the BDBV-HR2-MPER epitope near its C terminus as a promising candidate. The immunogen was fused to one component of a self-assembling, two-component nanoparticle and tested for immunogenicity in rabbits. Robust titers of cross-reactive serum antibodies to BDBV and EBOV GPs and moderate titers to SUDV GP were induced following immunization. To confirm the structural composition of the immunogens, solution NMR studies were conducted and revealed structural flexibility in the C-terminal residues of the epitope. Overall, our study represents the first report on an epitope-focused immunogen design based on the structurally challenging BDBV-HR2-MPER epitope.

Development of a rapid point-of-care test that measures neutralizing antibodies to SARS-CoV-2

BACKGROUND

After receiving a COVID-19 vaccine, most recipients want to know if they are protected from infection and for how long. Since neutralizing antibodies are a correlate of protection, we developed a lateral flow assay (LFA) that measures levels of neutralizing antibodies from a drop of blood. The LFA is based on the principle that neutralizing antibodies block binding of the receptor-binding domain (RBD) to angiotensin-converting enzyme 2 (ACE2).

METHODS

The ability of the LFA was assessed to correctly measure neutralization of sera, plasma or whole blood from patients with COVID-19 using SARS-CoV-2 microneutralization assays. We also determined if the LFA distinguished patients with seasonal respiratory viruses from patients with COVID-19. To demonstrate the usefulness of the LFA, we tested previously infected and non-infected COVID-19 vaccine recipients at baseline and after first and second vaccine doses.

RESULTS

The LFA compared favorably with SARS-CoV-2 microneutralization assays with an area under the ROC curve of 98%. Sera obtained from patients with seasonal coronaviruses did not show neutralizing activity in the LFA. After a single mRNA vaccine dose, 87% of previously infected individuals demonstrated high levels of neutralizing antibodies. However, if individuals were not previously infected, only 24% demonstrated high levels of neutralizing antibodies after one vaccine dose. A second dose boosted neutralizing antibody levels just 8% higher in previously infected individuals, but over 63% higher in non-infected individuals.

CONCLUSIONS

A rapid, semi-quantitative, highly portable and inexpensive neutralizing antibody test might be useful for monitoring rise and fall in vaccine-induced neutralizing antibodies to COVID-19.

Pan-ebolavirus protective therapy by two multifunctional human antibodies

Ebolaviruses cause a severe and often fatal illness with the potential for global spread. Monoclonal antibody-based treatments that have become available recently have a narrow therapeutic spectrum and are ineffective against ebolaviruses other than Ebola virus (EBOV), including medically important Bundibugyo (BDBV) and Sudan (SUDV) viruses. Here, we report the development of a therapeutic cocktail comprising two broadly neutralizing human antibodies, rEBOV-515 and rEBOV-442, that recognize non-overlapping sites on the ebolavirus glycoprotein (GP). Antibodies in the cocktail exhibited synergistic neutralizing activity, resisted viral escape, and possessed differing requirements for their Fc-regions for optimal in vivo activities. The cocktail protected non-human primates from ebolavirus disease caused by EBOV, BDBV, or SUDV with high therapeutic effectiveness. High-resolution structures of the cocktail antibodies in complex with GP revealed the molecular determinants for neutralization breadth and potency. This study provides advanced preclinical data to support clinical development of this cocktail for pan-ebolavirus therapy.

Cell Migration Driven by Self-Generated Integrin Ligand Gradient on Ligand-Labile Surfaces

Integrin-ligand interaction mediates the adhesion and migration of many metazoan cells. Here, we report a unique mode of cell migration elicited by the lability of integrin ligands. We found that stationary cells spontaneously turn migratory on substrates where integrin ligands are subject to depletion by cellular force. Using TGT, a rupturable molecular linker, we quantitatively tuned the rate of ligand rupture by cellular force and tested platelets (anucleate cells), CHO-K1 cells (nucleated cells), and other cell types on TGT surfaces. These originally stationary cells readily turn motile on the uniform TGT surface, and their motility is correlated with the ligand depletion rate caused by cells. We named this new migration mode ligand-depleting (LD) migration. Through both experiments and simulations, we revealed the biophysical mechanism of LD migration. We found that the cells create and maintain a gradient of ligand surface density underneath the cell body by constantly rupturing local ligands, and the gradient in turn drives and guides cell migration. This is reminiscent of the phenomenon that some liquid droplets or solid beads can spontaneously move on homogeneous surfaces by chemically forming and maintaining a local gradient of surface energy. Here, we showed that cells, as living systems, can harness a similar mechanism to migrate. LD migration is beneficial for cells to maintain adhesion on ligand-labile surfaces, and might also play a role in the migration of cancer cells, immune cells, and platelets that deplete adhesive ligands of the matrix.

Structural and functional analysis of cooperativity in a potent human antibody cocktail against Ebola virus

Structural principles underlying the composition of protective antiviral monoclonal antibody (mAb) cocktails are poorly defined. Here, we exploited antibody cooperativity to develop a therapeutic mAb cocktail against Ebola virus (EBOV). Systematic analysis of antibody repertoire in the human survivors identified a pair of potently neutralizing mAbs that cooperatively bind to the ebolavirus glycoprotein (GP). High-resolution structures revealed that in a two-antibody cocktail, molecular mimicry was a major feature of mAb/GP interactions. Broadly neutralizing mAb rEBOV-520 targeted a conserved epitope on the GP base region. MAb rEBOV-548 bound to a glycan cap epitope, possessed neutralizing and Fc-mediated effector function activities, and potentiated neutralization by rEBOV-520. Remodeling of the glycan cap structures by the cocktail enabled enhanced GP binding and virus neutralization. The cocktail demonstrated high levels of effectiveness against EBOV in nonhuman primates. These data illuminate structural principles of antibody cooperativity with implications for the design and development of antiviral immunotherapeutics.

Analysis of a Therapeutic Antibody Cocktail Reveals Determinants for Cooperative and Broad Ebolavirus Neutralization

Structural principles underlying the composition of protective antiviral monoclonal antibody (mAb) cocktails are poorly defined. Here, we exploited antibody cooperativity to develop a therapeutic mAb cocktail against Ebola virus. We systematically analyzed the antibody repertoire in human survivors and identified a pair of potently neutralizing mAbs that cooperatively bound to the ebolavirus glycoprotein (GP). High-resolution structures revealed that in a two-antibody cocktail, molecular mimicry was a major feature of mAb-GP interactions. Broadly neutralizing mAb rEBOV-520 targeted a conserved epitope on the GP base region. mAb rEBOV-548 bound to a glycan cap epitope, possessed neutralizing and Fc-mediated effector function activities, and potentiated neutralization by rEBOV-520. Remodeling of the glycan cap structures by the cocktail enabled enhanced GP binding and virus neutralization. The cocktail demonstrated resistance to virus escape and protected non-human primates (NHPs) against Ebola virus disease. These data illuminate structural principles of antibody cooperativity with implications for development of antiviral immunotherapeutics.

Food value and basic parasitosis of fish used in food by indigenous populations of Yakutia

The article presents the results of studies of nutritional value and the degree of infection with parasitoses of Siberian vendace (Coregonus sardinella Vallenciennes, 1848) and Yakut crucian carp (Carassius carassius jacuticus Kirillov, 1972). By the amount of protein, the Siberian vendace is classified as medium-protein, in terms of fat content, it is especially fatty fish and of high calories. It has been established that a distinctive feature of the Yakut crucian carps compared to European ones is high fat content (up to 10 % versus 2.5 %), high content of polyunsaturated fatty acids, macro- and microelements, vitamins, and have high energy value. The most common parasitic diseases of the crucian carp and vendace, affecting the quality and appearance of the fish, are myxosporidioses caused by Myxobolus, digramosis and phylometroidosis, the negative impact on the quality of which depends on the parasite infection intensity.

Sevoflurane postconditioning is not mediated by ferritin accumulation and cannot be rescued by simvastatin in isolated streptozotocin-induced diabetic rat hearts

Sevoflurane postconditioning (sevo postC) is an attractive and amenable approach that can protect the myocardium against ischemia/reperfusion (I/R)-injury. Unlike ischemic preconditioning (IPC), sevo postC does not require additional induced ischemic periods to a heart that is already at risk. IPC was previously shown to generate myocardial protection against I/R-injury through regulation of iron homeostasis and de novo ferritin synthesis, a process found to be impaired in the diabetic state. The current study investigated whether alterations in iron homeostasis and ferritin mRNA and protein accumulation are also involved in the cardioprotective effects generated by sevo postC. It was also investigated whether the protective effects of sevo postC in the diabetic state can be salvaged by simvastatin, through inducing nitric oxide (NO) bioavailability/activity, in isolated streptozotocin (STZ)-induced diabetic hearts (DH). Isolated rat hearts from healthy Controls and diabetic animals were retrogradely perfused using the Langendorff configuration and subjected to prolonged ischemia and reperfusion, with and without (2.4 and 3.6%) sevo postC and/or pre-treatment with simvastatin (0.5 mg/kg). Sevo postC significantly reduced infarct size and improved myocardial function in healthy Controls but not in isolated DH. The sevo postC mediated myocardial protection against I/R-injury was not associated with de novo ferrtin synthesis. Furthermore, simvastatin aggravated myocardial injury after sevo postC in STZ-induced DHs, likely due to increasing NO levels. Despite the known mechanistic overlaps between PC and postC stimuli, distinct differences underlie the cardioprotective interventions against myocardial I/R-injury and are impaired in the DH. Sevo postC mediated cardioprotection, unlike IPC, does not involve de novo ferritin accumulation and cannot be rescued by simvastatin in STZ-induced DHs.

Multifunctional Pan-ebolavirus Antibody Recognizes a Site of Broad Vulnerability on the Ebolavirus Glycoprotein

Ebolaviruses cause severe disease in humans, and identification of monoclonal antibodies (mAbs) that are effective against multiple ebolaviruses are important for therapeutics development. Here we describe a distinct class of broadly neutralizing human mAbs with protective capacity against three ebolaviruses infectious for humans: Ebola (EBOV), Sudan (SUDV), and Bundibugyo (BDBV) viruses. We isolated mAbs from human survivors of ebolavirus disease and identified a potent mAb, EBOV-520, which bound to an epitope in the glycoprotein (GP) base region. EBOV-520 efficiently neutralized EBOV, BDBV, and SUDV and also showed protective capacity in relevant animal models of these infections. EBOV-520 mediated protection principally by direct virus neutralization and exhibited multifunctional properties. This study identified a potent naturally occurring mAb and defined key features of the human antibody response that may contribute to broad protection. This multifunctional mAb and related clones are promising candidates for development as broadly protective pan-ebolavirus therapeutic molecules.

Broadly neutralizing antibodies from human survivors target a conserved site in the Ebola virus glycoprotein HR2-MPER region

Ebola virus (EBOV) in humans causes a severe illness with high mortality rates. Several strategies have been developed in the past to treat EBOV infection, including the antibody cocktail ZMapp^TM that has been shown to be effective in nonhuman primate models of infection¹ and has been used under compassionate-treatment protocols in humans². ZMapp^TM is a mixture of three chimerized murine monoclonal antibodies (mAbs)^3–6 that target EBOV-specific epitopes on the surface glycoprotein (GP)^7,8. However, ZMapp^TM mAbs do not neutralize other species from the Ebolavirus genus, such as Bundibugyo virus (BDBV), Reston virus (RESTV) or Sudan virus (SUDV). Here we describe three naturally-occurring human cross-neutralizing mAbs, from BDBV survivors, that target an antigenic site in the canonical heptad repeat 2 (HR2) region near the membrane proximal external region (MPER) of GP. The identification of a conserved neutralizing antigenic site in the GP suggests that these mAbs could be used to design universal antibody therapeutics against diverse ebolavirus species. Furthermore, we found that immunization with a peptide comprising the HR2/MPER antigenic site elicits neutralizing antibodies in rabbits. Structural features determined by conserved residues in the antigenic site described here could inform an epitope-based vaccine design against infection caused by diverse ebolavirus species.

Bat rabies in Guatemala

Rabies in bats is considered enzootic throughout the New World, but few comparative data are available for most countries in the region. As part of a larger pathogen detection program, enhanced bat rabies surveillance was conducted in Guatemala, between 2009 and 2011. A total of 672 bats of 31 species were sampled and tested for rabies. The prevalence of rabies virus (RABV) detection among all collected bats was low (0.3%). Viral antigens were detected and infectious virus was isolated from the brains of two common vampire bats (Desmodus rotundus). RABV was also isolated from oral swabs, lungs and kidneys of both bats, whereas viral RNA was detected in all of the tissues examined by hemi-nested RT-PCR except for the liver of one bat. Sequencing of the nucleoprotein gene showed that both viruses were 100% identical, whereas sequencing of the glycoprotein gene revealed one non-synonymous substitution (302T,S). The two vampire bat RABV isolates in this study were phylogenetically related to viruses associated with vampire bats in the eastern states of Mexico and El Salvador. Additionally, 7% of sera collected from 398 bats demonstrated RABV neutralizing antibody. The proportion of seropositive bats varied significantly across trophic guilds, suggestive of complex intraspecific compartmentalization of RABV perpetuation.

Raccoon rabies virus variant transmission through solid organ transplantation

IMPORTANCE

The rabies virus causes a fatal encephalitis and can be transmitted through tissue or organ transplantation. In February 2013, a kidney recipient with no reported exposures to potentially rabid animals died from rabies 18 months after transplantation.

OBJECTIVES

To investigate whether organ transplantation was the source of rabies virus exposure in the kidney recipient, and to evaluate for and prevent rabies in other transplant recipients from the same donor.

DESIGN

Organ donor and all transplant recipient medical records were reviewed. Laboratory tests to detect rabies virus-specific binding antibodies, rabies virus neutralizing antibodies, and rabies virus antigens were conducted on available specimens, including serum, cerebrospinal fluid, and tissues from the donor and the recipients. Viral ribonucleic acid was extracted from tissues and amplified for nucleoprotein gene sequencing for phylogenetic comparisons.

MAIN OUTCOMES AND MEASURES

Determination of whether the donor died from undiagnosed rabies and whether other organ recipients developed rabies.

RESULTS

In retrospect, the donor's clinical presentation (which began with vomiting and upper extremity paresthesias and progressed to fever, seizures, dysphagia, autonomic dysfunction, and brain death) was consistent with rabies. Rabies virus antigen was detected in archived autopsy brain tissue collected from the donor. The rabies viruses infecting the donor and the deceased kidney recipient were consistent with the raccoon rabies virus variant and were more than 99.9% identical across the entire N gene (1349/1350 nucleotides), thus confirming organ transplantation as the route of transmission. The 3 other organ recipients remained asymptomatic, with rabies virus neutralizing antibodies detected in their serum after completion of postexposure prophylaxis (range, 0.3-40.8 IU/mL).

CONCLUSIONS AND RELEVANCE

Unlike the 2 previous clusters of rabies virus transmission through solid organ transplantation, there was a long incubation period in the recipient who developed rabies, and survival of 3 other recipients without pretransplant rabies vaccination. Rabies should be considered in patients with acute progressive encephalitis of unexplained etiology, especially for potential organ donors. A standard evaluation of potential donors who meet screening criteria for infectious encephalitis should be considered, and risks and benefits for recipients of organs from these donors should be evaluated.

An electrochemiluminescence assay for analysis of rabies virus glycoprotein content in rabies vaccines

Vaccine potency testing is necessary to evaluate the immunogenicity of inactivated rabies virus (RABV) vaccine preparations before human or veterinary application. Currently, the NIH test is recommended by the WHO expert committee to evaluate RABV vaccine potency. However, numerous disadvantages are inherent concerning cost, number of animals and biosafety requirements. As such, several in vitro methods have been proposed for the evaluation of vaccines based on RABV glycoprotein (G) quality and quantity, which is expected to correlate with vaccine potency. In this study an antigen-capture electrochemiluminescent (ECL) assay was developed utilizing anti-RABV G monoclonal antibodies (MAb) to quantify RABV G. One MAb 2-21-14 was specific for a conformational epitope so that only immunogenic, natively folded G was captured in the assay. MAb 2-21-14 or a second MAb (62-80-6) that binds a linear epitope was used for detection of RABV G. Vaccine efficacy was also assessed in vivo using pre-exposure vaccination of mice. Purified native RABV G induced a RABV neutralizing antibody (rVNA) response with a geometric mean titer of 4.2IU/ml and protected 100% of immunized mice against RABV challenge, while an experimental vaccine with a lower quality and quantity of G induced a rVNA titer<0.05IU/ml and protected <50% of immunized mice. These preliminary results support the hypothesis that in vivo immunogenicity may be predicted from the in vitro measurement of RABV G using an ECL assay. Based upon these results, the ECL assay may have utility in replacement of the NIH test.

Predictive factors for the occurrence of idiopathic menorrhagia: evidence for a hereditary trait

The aim of the present study was to assess predictive factors for occurrence of idiopathic menorrhagia (IM), a disease characterized by abnormal endometrial blood vessel morphology. It was hypothesized that IM exhibits familial clustering (suggesting inheritance) and is associated with other vascular abnormalities, primarily cutaneous hemangiomas. Women with IM (n=152) and healthy, regularly menstruating (n=56) women answered a questionnaire concerning menstrual pattern, susceptibility to bleeding and family history of abnormal gynecological bleeding. Factor analysis with principal component extraction was used to separate predictive factors that may be associated with IM. A total of 35 different items were analyzed. A strong association was found between IM and a family history of heavy menstrual bleeding (r=0.68), but not with cutaneous vascular abnormalities. Our results revealed that a family history of heavy menstrual bleeding may have the highest predictive value for the diagnosis of IM, indicating a hereditary trait.

Evaluation of the effects of topical clobetasol propionate by visual score, electrical impedance and laser Doppler flowmetry

BACKGROUND/PURPOSE

The intensity of steroid-induced skin blanching is usually evaluated subjectively by a trained observer using a visual score although a few methods have been described for doing this objectively. In this study we wished to establish whether the effects of topical steroids can be detected by measuring the electrical impedance of the skin.

METHODS

Ten healthy volunteers were treated with three concentrations of clobetasol propionate (0.005, 0.05, and 0.5 mg/mL) on the forearm covered by a dressing overnight. On the following morning, we assessed dermal blanching using a visual score, laser Doppler flowmetry and electrical impedance.

RESULTS

Using the visual score, we found dose-response blanching at all concentrations of clobetasol propionate. The laser Doppler flow values declined significantly after the application of clobetasol propionate (0.005 mg/mL (P<0.01) and 0.5 mg/mL (P<0.05)), as compared with the test site treated with the vehicle alone. Electrical impedance showed a significant increase in phase index after the application of 0.05 mg (P<0.01) and 0.5 mg (P<0.01) of clobetasol propionate, and a significant reduction in real part index after of 0.05 mg/mL (P<0.05) and 0.5 mg/mL (P<0.05) compared with the test site treated with the vehicle alone. The magnitude index and imaginary part index were not affected by this steroid.

CONCLUSION

Our findings indicate that the dermal blanching induced by topical corticosteroids can be evaluated with a skin impedance spectrometer.

Biophysical assessment of atopic dermatitis skin and effects of a moisturizer

BACKGROUND

The mechanisms of the skin barrier impairment in patients with atopic dermatitis (AD) are still unknown and need further studying.

OBJECTIVE

We evaluated the skin of healthy subjects and of patients having atopic dermatitis with an instrument measuring electrical impedance and other noninvasive methods (transepidermal water loss, capacitance) and studied the effects of a new emollient [Proderm (Pro-Q in the USA)].

METHODS

After a 2-week washout period, we treated clinically noneczematous skin on the forearm of 24 patients with AD and assessed the effects with the noninvasive methods. 22 healthy subjects were used as controls.

RESULTS

The findings indicate that barrier function and hydration, and certain patterns of electrical impedance of AD skin are abnormal compared with normal skin. Moreover, there was an increase in hydration in patients' skin after treatment and a reversal of certain impedance indices towards normal.

CONCLUSIONS

Our findings demonstrate that the moisturizer we used changes some biophysical parameters when applied to atopic skin. In addition, a technique based on electrical impedance seems to give valuable information in atopic skin studies, especially the effects of moisturizers.

Non-invasive preoperative assessment of basal cell carcinoma of nodular and superficial types

BACKGROUND/AIMS

Although various biophysical properties can be used to distinguish basal cell carcinoma (BCC) tissue from normal skin, none permits typing of the tumour. In this study, we assessed nodular (NBCC) and superficial (SBCC) types of BCC using three different non-invasive instruments and placed special emphasis on their clinical value as diagnostic tools.

METHODS

We included 35 patients with 35 tumours (15 NBCC and 20 SBCC), which had been diagnosed clinically. All lesions were evaluated preoperatively with an instrument measuring electrical impedance (IMP). Methods for determining transepidermal water loss (TEWL) and laser Doppler (LD) were also used. Measurements were also made in healthy skin on the contralateral side as reference. The diagnosis was confirmed by histological examination.

RESULTS

We found clear differences between the lesions and their reference values, using all three bioengineering techniques for NBCC and SBCC. The biophysical parameters of all types vary with anatomical location. Since most of the NBCC were located on the face and most SBCC on the trunk, their baseline impedance characteristics (i.e., impedance indices magnitude index (MIX) and imaginary part index (IMIX)) differed significantly. We therefore compared delta (a difference between the reference and tumour) MIX and IMIX of NBCC and SBCC instead of the absolute figures. We found no significant differences in TEWL, blood flow and IMP between the two types of BCC and attribute this to biological variation and electromagnetic noise.

CONCLUSIONS

As with LD and TEWL, definite differences in IMP were detected between healthy skin and BCC lesions. However, at this stage of development of the bioimpedance technique, we were unable to distinguish between the two types of BCC. An improved IMP device with semi- invasive probes or a more sophisticated type of data analysis may increase the diagnostic usefulness of the IMP method.

Effects of Pretreatment with a Urea-containing Emollient on Nickel Allergic Skin Reactions

The aim of this study was to evaluate the effect of a moisturizer containing urea on allergic contact dermatitis. Twenty-five nickel-sensitized patients and five controls (non-sensitized volunteers) applied such a moisturizer on the volar side of one forearm twice daily for 20 days, while the other forearm served as the control. After treatment with the moisturizer, patch tests with 0%, 0.5% and 2% NiSO4 in petrolatum were applied in a randomized manner on each arm. After 72 h, the skin reactions were blindly evaluated by clinical scoring and by measuring transepidermal water loss and electrical impedance. After treatment, the baseline transepidermal water loss values were lower and the baseline magnitude impedance index values were higher on the pretreated forearm. According to clinical scoring and measurements with the two physical measurement techniques, the degree of the patch test reactions was equal. All control subjects had negative nickel tests. We concluded that the skin reactivity to nickel in nickel-sensitized patients is not significantly affected by use of the urea-containing moisturizer.

Basal electrical impedance in relation to sodium lauryl sulphate-induced skin reactions - a comparison of patients with eczema and healthy controls

BACKGROUND

Identification of subjects at risk for contact dermatitis by screening tests is desirable in order to adjust the preventive measures to individual skin susceptibility. The present study aimed to examine the effects of basic physiological features, such as baseline electrical impedance (IMP) and transepidermal water loss (TEWL), on reactivity to sodium lauryl sulphate (SLS).

METHODS

On the basis of two previous studies, we re-evaluated the experimental irritant skin reactions (50 microL of 2% SLS in large Finn Chambers for 24 h) on the volar forearms of 29 patients with eczema and 19 healthy controls.

RESULTS

We found definite differences in the baseline values of IMP, between the patients and the controls. Moreover, patients with eczema showed higher TEWL and lower MIX values on day 3 after exposure to SLS, which may indicate differences in SLS reactivity. After the study, the biophysical parameters of the eczema patients did not return to baseline, which suggests that their skin heals more slowly than that of normal subjects.

CONCLUSIONS

Our findings indicate that the IMP technique may help to 'detect' chemically vulnerable skin. However, more studies are needed to determine the value of the basal electrical impedance parameters in assessing the risk of developing irritant contact dermatitis.

Assessment of irritant skin reactions using electrical impedance--a comparison between 2 laboratories

To assess interlaboratory variability in the measurement of skin electrical impedance (IMP), we evaluated irritant reactions to sodium lauryl sulfate (SLS) (2%) and nonanoic acid (NAA) (40%) in 2 laboratories. We studied the patch test responses in 40 healthy male and female volunteers between 20 and 30 years of age (20 in each laboratory) with an instrument for measuring IMP. 2 other bioengineering methods and visual scoring were also used to facilitate further illumination of any findings. A strict protocol including all details of the measurement procedure was carefully implemented in both laboratories. The skin reactions were evaluated at 23 h and at 3, 7 and 14 days after exposure. Our findings show that both irritants caused distinct dynamic responses detectable with the bioengineering techniques. Interestingly, the IMP baseline values varied between the 2 laboratories. Moreover, at early stages in the development of irritation (day 1), the irritants induced changes in IMP indices in the opposite direction, which accords with the concept of various IMP patterns of contact dermatitis caused by different irritants. Although the absolute values of IMP differed in both laboratories, the dynamic response patterns were the same.

Electrical impedance as a potential tool to distinguish between allergic and irritant contact dermatitis

BACKGROUND AND OBJECTIVE

The allergic contact reaction is a model reaction for studying the cell-mediated immune system of the skin. In this study we use a noninvasive method, electrical impedance (IMP), to compare nickel (Ni) allergic contact reactions with an irritant contact reaction induced by sodium lauryl sulfate, which has already been carefully evaluated with this method. For this purpose, we included only Ni- and sodium lauryl sulfate-induced reactions of very similar appearance.

METHODS

Various concentrations of Ni sulfate in distilled water were applied on the volar aspect of the forearms of 33 adult women who were allergic to Ni. Assessments were made using visual scoring, a new IMP technique, and transepidermal water loss 3 and 7 days later.

RESULTS

In the 19 patients who completed the study, 3 of the 4 impedance indices were significantly lower at the sodium lauryl sulfate sites than at the Ni sites on day 3; ie, the mean magnitude (MIX) (P < or = .001), imaginary part (IMAX) (P < or = .001), and real part (RIX) indices (P < or = .01). Unlike the irritant reactions, no significant increases in transepidermal water loss occurred in the allergic contact reactions. This may be because, in reactions of the studied magnitude, an allergic contact reaction does not significantly affect the epidermis because the inflammatory process is located deeper in the dermis than an irritant reaction.

CONCLUSION

This study suggests that IMP, as used herein, is suitable for distinguishing between contact reactions of allergic and irritant nature. Although pathophysiologic events in the tissue studied significantly modify impedance patterns, little is known about how to interpret the structural and chemical changes underlying these patterns. Studies are needed to determine the relation between anatomic or pathophysiologic parameters, and the findings using IMP and other established methods, such as chemical extraction and histopathology.

Urea and sodium chloride in moisturisers for skin of the elderly--a comparative, double-blind, randomised study

Urea has long been used to treat dry skin. In the present report, we compared two identical creams, with the exception that one contained both urea and sodium chloride and the other urea alone, in 23 healthy elderly subjects. Following a 2-week wash-out, their clinically non-eczematous, rough- or normal-appearing skin on the anterior proximal part of the lower legs was treated twice daily in a double-blind and randomised manner. We examined the treated areas by measuring transepidermal water loss, capacitance and electrical impedance. Our findings suggest that both moisturisers seem equally effective, at least concerning the ability to reverse impedance indices towards normal, an effect ascribed to changes in hydration of the stratum corneum. However, the relevance of the impedance parameters to the clinical picture is disputable and further studies of moisturisers in elderly subjects are needed.

Magnetically isolated Cu(II)Gd(III) pairs in the series [Cu(acacen)Gd(pta)(3)], [Cu(acacen)Gd(hfa)(3)], [Cu(salen)Gd(pta)(3)], and [Cu(salen)Gd(hfa)(3)], [acacen = N,N'-ethylenebis(acetylacetoniminate(-)), salen = N,N'-ethylenebis(salicylideniminate(-)), hfa = 1,1,1,5,5,5-hexafluoropentane-2,4-dionate(-), pta = 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dionate(-)]

[Cu(salen)Gd(pta)(3)] (1), [Cu(acacen)Gd(pta)(3)] (2), and [Cu(acacen)Gd(hfa)(3)] (3) are three heterobimetallic [Cu(II)Gd(III)] complexes of general formula [Cu(SB)Gd(beta-dik)(3)], in which a N,N',O,O' Schiff base (SB) ligand [acacen = N,N'-ethylenebis(acetylacetoniminate(-)), salen = N,N'-ethylenebis(salicylideneiminate(-))] tetracoordinates Cu(II) and chelates Gd(III) as a tris(beta-diketonate) complex [hfa = 1,1,1,5,5,5-hexafluoropentane-2,4-dionate(-); pta = 1,1,1-trifluoro-5,5-dimethylhexane-2,4-dionate(-)]. They crystallize as a triclinic structure (space group P). The cell parameters are a = 9.8616(10) A, b = 12.1976(13) A, c = 18.4187(22) A, alpha = 90.671(14) degrees, beta = 100.588(13) degrees, gamma = 103.684(12) degrees, V = 2113 A(3), and Z = 2 for 1; a = 9.7560(11) A, b = 12.2924(13) A, c = 18.9368(22) A, alpha = 88.449(14) degrees, beta = 87.269(14) degrees, gamma = 67.629(12) degrees, V = 2098 A(3), and Z = 2 for 2; and a = 12.5726(15) A, b = 15.5985(18) A, c = 18.3724(21) A, alpha = 85.963(13) degrees, beta = 85.411(14) degrees, gamma = 80.766(14) degrees, V = 3539 A(3), and Z = 4 for 3. The Cu(O,O')Gd bridging cores show folding angles about O,O' in the range 139 degrees -147 degrees and intramolecular Cu small middle dot small middle dot small middle dotGd distances of about 3.3 A. In the solid state, the molecules form centrosymmetric pseudodimers [Cu(SB)Gd(beta-dik)(3)](2), through the overlap of the Cu(SB) entities. Resulting intradimer Cu...Cu distances are 5.941(1) A for 1, 4.831(1) A for 2, and 4.511(1) and 3.868(1) A for 3 which comprises two symmetrically independent dimers. The temperature dependence of complexes 1-3 was investigated in the range 1.8-300 K and revealed weak ferromagnetic interactions. Results are discussed in light of the structural features and of available magnetostructural data for other heterobimetallic [Cu(II)Gd(III)] complexes, including [Cu(salen)Gd(hfa)(3)] (4) (Ramade, I.; Kahn, O.; Jeannin, Y.; Robert, F. Inorg. Chem. 1997, 36, 930-936).

The Russian version of the Childhood Health Assessment Questionnaire (CHAQ) and the Child Health Questionnaire (CHQ)

We report herein the results of the cross-cultural adaptation and validation into the Russian language of the parent's version of two health related quality of life instruments. The Childhood Health Assessment Questionnaire (CHAQ) is a disease specific health instrument that measures functional ability in daily living activities in children with juvenile idiopathic arthritis (JIA). The Child Health Questionnaire (CHQ) is a generic health instrument designed to capture the physical and psychosocial well-being of children independently from the underlying disease. The Russian CHAQ CHQ were fully validated with 3 forward and 3 backward translations. A total of 146 subjects were enrolled: 86 patients with JIA (23% systemic onset, 39% polyarticular onset, 15% extended oligoarticular subtype, and 23% persistent oligoarticular subtype) and 60 healthy children. The CHAQ clinically discriminated between healthy subjects and JIA patients, with the systemic, polyarticular and extended oligoarticular subtypes having a higher degree of disability, pain, and a lower overall well-being when compared to their healthy peers. Also the CHQ clinically discriminated between healthy subjects and JIA patients, with the systemic onset, polyarticular onset and extended oligoarticular subtypes having a lower physical and psychosocial well-being when compared to their healthy peers. In conclusion the Russian version of the CHAQ-CHQ is a reliable, and valid tool for the functional, physical and psychosocial assessment of children with JIA.