Decreased FMR1 mRNA levels found in men with substance use disorders

FMR1 gene (fragile X mental retardation 1) represents a genetic and epigenetic factor in a number of human diseases. Though the role of FMR1 gene in substance use disorders (SUDs) is not well studied, a number of investigations indicate that SUDs and FMR1-accociated disorders may share common underlying mechanisms. We examined the relative FMR1 mRNA levels and their sex-distribution in leukocytes from patients with alcohol and drug dependence compared to healthy controls. The study included 44 participants, 16 with alcohol dependence (mean age 43, 10 males and 6 females), 17 with drug dependence (mean age 41, 12 males and 5 females) and 11 healthy controls (mean age 47, 5 males and 6 females). Participants donated 5–6 ml of blood and completed a specialized questionnaire. Total RNA was isolated and cDNA was synthesized and used as a template for qRT-PCR analysis. The studied persons with alcohol and drug dependence share common socio-demographic and substance-use related characteristics. Significant FMR1 down-regulation was observed in the alcohol dependent group (25 % decrease; p = 0.005). Sex-associated analysis revealed that FMR1 down-regulation was primarily in alcohol-dependent men (40% decrease; p = 0.001) and did not reach significance in women. A similar sex-dependent pattern was observed among drug-dependent individuals. Drug-dependent men had significantly lower FMR1 mRNA levels (24% decrease; p = 0.015) compared with controls, while no significant difference was observed in drug-dependent females. These data indicate FMR1 mRNA down-regulation in persons with alcohol- and drug-dependence, relative to controls, is sex-dependent. This implies a role for FMR1 in substance use disorders. These findings require confirmation by including protein measures and the recruitment of larger cohorts.

Antiproliferative Properties Against Human Breast, Cervical and Ovarian Cancer Cell Lines, and Antioxidant Capacity of Leaf Aqueous Ethanolic Extract from Cotinus coggygria Scop

Cotinus coggygria Scop. leaf aqueous ethanolic extract was examined for its in vitro antiproliferative and antioxidant activity. Antiproliferative effect was assessed on four human gynecological cancer cell lines: breast (MCF7, T47D), cervical (HeLa) and ovarian (A2780) and compared to the cell growth inhibitory effect on non-cancerous breast epithelial cell line MCF10A using MTT cell proliferation assay. Radical scavenging assay with DPPH was applied to evaluate antioxidant potential of the extract. The obtained results showed that the herb inhibited cell growth of all of the tested cancer cell lines and the highest was the cytostatic effect on A2780 cells with a half maximal inhibitory concentration (IC50) value of 30.8 μg/ml. For the other cell lines the IC50 values were in the range of 55-122.7 μg/ml. Additionally, the extract exerted considerably weaker reduction in cell proliferation of the non-cancerous cell line MCF10A compared to cancer cells, which indicates for antiproliferative selectivity. C. coggygria extract showed high free radical scavenging activity with an IC50 value of 11.2 μg/ml. The obtained data provide evidence for pharmacological potential of the tested extract and future more detailed studies concerning the molecular mechanisms of the anticancer effect of the herb are needed.

[INVESTIGATION ON ANTIFUNGAL SUSCEPTIBILITY OF CANDIDA YEASTS IN PREGNANT PATIENTS WITH CONFIRMED VULVOVAGINAL CANDIDIASIS AND THEIR NEWBORNS.]

Background Vulvovaginal candidiasis (VVU) is considered as a special risk factor during pregnancy, with important influence on the reproductive function of the patients and on the morbidity in the newborns from mothers with VVC. Maternal VVC is a major risk factor for the development of candida-colonization of the infant, which in turn is the first step towards the development of mucocutaneous or systemic candidiasis and Candida-septicemia in the newborn. In pregnant patients, the possible applicable local and systemic medications are limited, while the therapeutic resistance in chronic recurrent forms of VVC increases, facts that require precision of the diagnosic approach to optimize the therapeutic recommendations in pregnant patients, considered as a high risk group. The aim of this study was to investigate in vitro antifungal susceptibility of Candida yeasts to current antifungal agents in pregnant patients with confirmed VVC before the act of birth. Material and Methods Vaginal secretions of 23 healthy pregnant women with proven Candida vaginitis were taken within 48 hours before birth and the presence of yeasls of Candida was confirmed by culture examination. Between 47-72 hours after birth, samples were taken for Candida colonization of the oralmucosa and feces of their newborns. Samples were plated on Sabouraud agar and cultured in an incubator for 2 to 3 days at a temperature of 25° C. Species identification of the isolated yeasts were performed by commercial API Candida test - API 20C AUX (BioMerieux, Marcy-l'Etoile, France). Part of the isolates was identified by commercial whale AUXACOLOR (BioRad, Mames la Coquette, France). Antifungal sensitivity of isolated strains was examined by applying commercial solicitation ready kit and methods of disc diffusion and E-test, as the aim of the authors was to assess their potential for use in the diagnosis, and the correlation between them. Results Candida albicans was the prevalent etiological agent in pregnant patients with VVC immediately before birth (n = 22, 91.67 +/- 0.06%). Positive Candida colonization was detected in 14 (58.33%) of their newborns (n = 24), as no statistically significant difference was established, depending on the mode of delivery. The investigated antifungal susceptibility with test Fungifast (ELITech Microbiology Reagents), found 100% sensitivity of Candida albicans to Amphotericin B, Flucytosin and Voriconazole. Intermediate susceptibility to Itraconazole was found in 6 of 23 (26%) maternal isolates, and 5 of 23 (22%) isolates were moderately sensitive to Fluconazole. Candida krusei showed complete resistance to Fluconazole and Itraconazole. Within the group of antifungals for topical application (Econazole, Ketoconazole, Miconazole, Nystatin), the results established that 100% of the studied fungi were sensitive to Nystatin, while within the groups of azoles for vaginal and topical use - C.krusei was 100% resistant, as the sensitivity of C. albicans varied between 60-80%. Conclusion Our recommendation, based on the esablished results is that in pregnant with uncomplicated VVC as a first-line therapy should be considered the group of vaginal azoles and Nystatin, while the systemic therapy should be considered carefully and only after the firSt trimester. In cases of oral and intestinal candidiasis in neonatology, we recommend a therapy with minimal absorbable antifungals as Nystatin and miconazole (amphotericin B is available in our country), while systemic antifungal should be initiated only as a second choice. The exact etiological diagnosis is especially important because in our country there is a tendency for increased incidence of non-albicans fungus resistant to therapy, and that changes the therapeutic behavior.

Molecular-Genetic Aspects of Breast Cancer

Breast cancer is the most frequent malignancy among women. Advances in breast cancer knowledge have deciphered the involvement of a number of tumor suppressor genes and proto-oncogenes in disease pathogenesis. These genes are part of the complex biochemical pathways, which enable cell cycle control and maintenance of genome integrity. Their function may be disrupted as a result of alterations in gene sequence or misregulation of gene expression including alterations in DNA methylation pattern. The present review summarizes the main findings on major breast cancer related genes BRCA1/2, p53, ATM, CHEK2, HER2, PIK3CA and their tumorigenic inactivation/activation. The potential clinical importance of these genes with respect to patients’ prognosis and therapy are also discussed. The possible implication of other putative breast cancer related genes is also outlined. The first elaborate data on the genetic and epigenetic status of the above mentioned genes concerning Bulgarian patients with the sporadic form of the disease are presented. The studies indicate for a characteristic mutational spectrum in some of the genes for the Bulgarian patients and specific correlation between the status of different genes and clinicopathological characteristics.

[Pain in the neonatal period. I -- physiological aspects, causes, response, diagnosis and long-term effects of neonatal pain]

Entering of high-tech methods used in the treatment of premature infants carries the risk of increased invasiveness which causes the pain and stress in them. The aim of this literature review is to present the achievements in the study of neonatal pain, causes and responses to it, the short-term effects on their status and their later development, as well as the ways of pain's assessment. The newborn after 26-30 weeks of gestation has functionally mature pain receptor apparatus. Numerous invasive procedures cause in the prematurely born baby psycho-physiological abnormalities (changes in heart rate, breathing, blood pressure and oxygen saturation) and behavioral abnormalities (facial expression, motion activity of the body and extremities, sleep disturbances, characteristics of crying). The last mentioned are basis for creating a rating scale for procedural and prolonged pain. Future studies are aimed at creating an universal scales.

CONCLUSION

At the time of intensive treatment, the premature infant is under the adverse effects of acute or repeated pain incentives. They worsen the status, prolong the hospital stay and influence the later neurological development and outcome of the premature infant. In everyday clinical practice, prevention of pain, establishing its severity and its evaluation reduce its negative effects on the newborn.

[Stillbirth rate and perinatal mortality--criteria for quality of prenatal obstetric care]

AIM

To determine the frequency and structure of stillbirth rate, its relative share compared to PM, the trends for the period of 2007-2012 and their dependence to birth weight of the fetus and newborn.

MATERIAL AND METHODS

The birth rate, stillbirth rate and PM for the period of 2007-2012 have been followed up retrospectively according to data provided by the department of Obstetrics & Gynecology in University hospital "St. George" Plovdiv. The trends of those two indicators have been established, their relationship to and dependence of fetal and newborn birth weight. Representative and correlative analyses have been used.

RESULTS

During the period being analyzed 13 558 deliveries have been registered. 13.4 per thousand (183) of them are stillbirths, and 92.3% (169) died antenatal. After 2010 the birth rate decreases. Stillbirth rate increases from 13 per thousand in 2009 to 20.6 per thousand in 2012. It is mostly due to prematurity, which for the past two years are mostly with extremely low birth weight (57.2%). Antenatal stillbirth rate prevails. Intranatal fetal death is being observed significantly less, but in those cases where it is, the premature with weight 600-999 grams play a major role. Increased stillbirth rate maintains a high PM and constitute more than 2/3 of it.

CONCLUSIONS

Against the backdrop of lower birth rate, the stillbirth rate and PM remain high. In the last 2 years they are presented mainly by premature weighing 600-999 grams. The prevalence of antenatal stillbirth rate means good control of delivery but refers to the prenatal period, which is related to the quality of the obstetric care.

[Dynamics in levels of procalcitonin in healthy term newborns during the first 24 hours of life]

Procalcitonin /PCT/ is a reliable marker for the diagnosis of early onset neonatal sepsis but its sensitivity and specificity in literature vary widely mostly due to existing unclarity on its normal values and kinetics in the postnatal period. Aim of our research is to study the normal values of PCT and its dynamics during the first 24 hours of life for the Bulgarian population.

MATERIALS & METHODS

70 healthy neonates were prospectively enrolled and separated in the following 3 groups (Group 1- immediately afterbirth; Group 2- 0-12 h afterbirth; Group 3- 12-24 h afterbirth) regarding the age at the time of PCT testing. The selected method of PCT testing is direct chemiluminescence. Results were analyzed with Statistical Package for Social Science (SPSS).

RESULTS

For group 1 and group 2 the mean PCT level was 0.06 and 0.59 ng/ml respectively. In group 3 PCT concentrations reached peak mean values of 3.35ng/ml. In the last group also the greatest variations were observed PCTmin - 0.31 ng/ml, PCTmax - 23.81 ng/ml. No correlation between PCT concentrations, sex, mode of delivery and parity was found.

CONCLUSION

During the first 24 hours of life PCT values in healthy term neonates show broad variations, most marked in the interval 12-24 h. The dynamics of PCT concentrations is characterized by a gradual increase from birth reaching peak levels approximately 24 hours later.

[The effect of vaginal sildenafil citrate on uterine blood flow and endometrium in the infertile women]

Evaluation of endometrial receptivity remains a challenge in clinical practice. Ultrasound evaluation of endometrial thickness and texture and measurement of uterine artery blood flow has been used for endometrial assessment.

AIM

To investigate the role of combination of sildenafil citrate and serophene on endometrial thickness, endometrial volume, endometrial FI and VFI on Angiohistogram, RI and PI to a. uterine on the day of hCG, in prediction of IUI outcome in infertile women.

MATERIALS AND METHODS

Forty two patients were selected randomly who had anovulatory infertility. In Sildenafil citrate plus Serophene group (Group I), patients got 25 mg sildenafil citrate (Silden) vaginally and Serophene 100-150 mg orally, and in Serophene group (Group II), 100-150 mg of Serophene was given orally.

RESULTS

Mean endometrial thickness and endometrial volume was 11.8 +/- 2.6 v/s 10.2 +/- 2.8 and 5.2 +/- 1.4 v/s 3.6 +/- 1.8 respectively in group I and in group II (p < 0.05). There was significant decrease in PI and RI to a. uterina in group I.

CONCLUSIONS

Combination of Sildenafil citrate and Serophene is an effective agent as a first-line of treatment for ovulation induction.

[Pain in the neonatal period II. non-pharmacological and pharmacological treatment]

In their postnatal development the newborns are often exposed to the influence of procedural and repetitive painful stimuli that worsen their status. This requires the implementation of non-pharmacological and pharmacological treatment. Aim - to explore the literature data on the possibilities of non-pharmacological and pharmacological treatment methods which are implemented to reduce and control pain in neonatal period. Some of the non-pharmacological strategies are the priority of the personnel who gives care of newborns (swaddling, nonnutritive sucking, usage of sweet solution, etc.) Ever more is discussed the participation of mother(parents)in the care of her child's comfort and pain reduction. The breastfeeding and "kangaroo" care additionally reduce negative effects of pain. The importance of the music continues to be explored. The principles of pharmacological therapy include: control of procedure pain, its treatment during mechanical ventilation and at the time and after surgical intervention which is based on analgesia. Specificities of the pharmacotherapy of newborns and premature infants require careful application of the medications and additional studies on these children.

CONCLUSION

The elimination of neonatal pain and its negative effects on the newborn is achieved by applying different strategies. Non-pharmacological methods reduce pain stimuli and ensure the child's comfort and the pharmacological methods block and eliminate the pain. Most often a combination of them is used in practice.

Spectroscopic detection of DNA quadruplexes by vibrational circular dichroism

The four-stranded G-quadruplex motif is a conformation frequently adopted by guanine-rich nucleic acids that plays an important role in biology, medicine, and nanotechnology. Although vibrational spectroscopy has been widely used to investigate nucleic acid structure, association of particular spectral features with the quadruplex structure has to date been ambiguous. In this work, experimental IR absorption and vibrational circular dichroism (VCD) spectra of the model quadruplex systems d(G)(8) and deoxyguanosine-5'-monophosphate (5'-dGMP) were analyzed using molecular dynamics (MD) and quantum-chemical modeling. The experimental spectra were unambiguously assigned to the quadruplex DNA arrangement, and several IR and VCD bands related to this structural motif were determined. Involvement of MD in the modeling was essential for realistic simulation of the spectra. The VCD signal was found to be more sensitive to dynamical structural variations than the IR signal. The combination of the spectroscopic techniques with multiscale simulations provides extended information about nucleic acid conformations and their dynamics.

A novel SOX9 nonsense mutation, q401x, in a case of campomelic dysplasia with XY sex reversal

Campomelic dysplasia (CD, MIM 114290) is a rare, often lethal, dominantly inherited, congenital skeletal dysplasia, associated with male-to-female autosomal sex reversal and due to de novo mutations of the SOX9 gene, a tissue-specific transcription factor gene involved both in skeletogenesis and male sexual differentiation. Here we report on a 4 months-old 46,XY sex reversed infant with typical clinical features for CD due to a novel mutation of the SOX9 gene, Q401X, leading to synthesis of a truncated SOX9 protein that completely lacks the C-terminal transactivation domain.

Analysis of the K-ras/B-raf/Erk signal cascade, p53 and CMAP as markers for tumor progression in colorectal cancer patients

Colorectal cancer patients may succumb to their disease because of local recurrence or formation of metastasis. To develop a prognostic tool for these fatal types of progression, 23 patients with colorectal carcinoma were included in this study for the detection at the time of surgery of the incidence of K-ras, B-raf and p53 mutations, the phosphorylation status of Erk and the expression of cystatin-like metastasis-associated protein (CMAP) in tumor, mucosa and liver samples. Polymerase chain reaction-restriction fragment length polymorphism and PCR-SSCP were used to detect the respective mutations. The results of these assays were complemented by sequencing the K-ras, B-raf and p53 mutations. A multiplex RT-PCR assay was used to detect the CMAP mRNA levels and the phosphorylation status of Erk in tumor samples was assessed by Western blot using a phosphospecific Erk antibody. The carcinomas were classified as stages T4 (70%), T3 (17%), T2 (9%) and T1 (4%) and thus represent a group of advanced colorectal carcinomas. The carcinomas (8 out of 23, 39.1%) were mutated in K-ras codons 12 or 13 and two patients had a B-raf (V599) mutation in their tumor. Of 22 tumors, 11 (50%) were positive for pErk, indicating the activation of the RAS/RAF/ERK signaling pathway. Of the 23 tumors, 13 (65.5%) showed an increased CMAP RNA level. Notably, 10 of these 13 patients have already died and two developed liver metastasis. Mutations in p53 were found in only 6 patients (26%), with 6 being detected in carcinoma, 1 in mucosa and 1 in liver tissue. These alterations were classified as non-sense (n=1), mis-sense (n=2) and frame-shift mutations (n=1) as well as intron polymorphisms (n=5). There was a significant correlation between Erk activation and K-ras codon 12 mutation (p=0.016), but not between K-ras codon 13 or B-raf mutations and Erk activation. Furthermore, there was a significant correlation of each positive marker with tumor stage (p=0.001).

Structures of the Ca2+-ATPase complexes with ATP, AMPPCP and AMPPNP. An FTIR study

We studied binding of ATP and of the ATP analogs adenosine 5'-(beta,gamma-methylene)triphosphate (AMPCP) and beta,gamma-imidoadenosine 5'-triphosphate (AMPPNP) to the Ca(2+)-ATPase of the sarcoplasmic reticulum membrane (SERCA1a) with time-resolved infrared spectroscopy. In our experiments, ATP reacted with ATPase which had AMPPCP or AMPPNP bound. These experiments monitored exchange of ATP analog by ATP and phosphorylation to the first phosphoenzyme intermediate Ca(2)E1P. These reactions were triggered by the release of ATP from caged ATP. Only small differences in infrared absorption were observed between the ATP complex and the complexes with AMPPCP and AMPPNP indicating that overall the interactions between nucleotide and ATPase are similar and that all complexes adopt a closed conformation. The spectral differences between ATP and AMPPCP complex were more pronounced at high Ca(2+) concentration (10 mM). They are likely due to a different position of the gamma-phosphate which affects the beta-sheet in the P domain.

Interactions of phosphate groups of ATP and Aspartyl phosphate with the sarcoplasmic reticulum Ca2+-ATPase: an FTIR study

Phosphate binding to the sarcoplasmic reticulum Ca2+-ATPase was studied by time-resolved Fourier transform infrared spectroscopy with ATP and isotopically labeled ATP ([beta-18O2, betagamma-18O]ATP and [gamma-18O3]ATP). Isotopic substitution identified several bands that can be assigned to phosphate groups of bound ATP: bands at 1260, 1207, 1145, 1110, and 1085 cm(-1) are affected by labeling of the beta-phosphate, bands likely near 1154, and 1098-1089 cm(-1) are affected by gamma-phosphate labeling. The findings indicate that the strength of interactions of beta- and gamma- phosphate with the protein are similar to those in aqueous solution. Two bands, at 1175 and 1113 cm(-1), were identified for the phosphate group of the ADP-sensitive phosphoenzyme Ca2E1P. They indicate terminal and bridging P-O bond strengths that are intermediate between those of ADP-insensitive phosphoenzyme E2P and the model compound acetyl phosphate in water. The bridging bond of Ca2E1P is weaker than for acetyl phosphate, which will facilitate phosphate transfer to ADP, but is stronger than for E2P, which will make the Ca2E1P phosphate less susceptible to attack by water.

Vibrational circular dichroism signature of hemiprotonated intercalated four-stranded i-DNA

The four-stranded intercalated DNA structure exemplified by the oligonucleotide 5'-d(CCCCCCCCCCCC) (d(C)12) was studied at acidic pH by infrared absorption (IR) and vibrational circular dichroism (VCD) spectroscopy and compared with spectra of the same oligonucleotide at neutral pH to establish distinct VCD markers for the intercalation motif. The most striking feature is a new absorption at 1694 cm(-1) and its corresponding VCD couplet with reversed sign. These are unique for the intercalated structure and have not been observed for other parallel stranded duplexes. Significant characteristic features resulting from the spatial arrangement of the sugar-phosphate backbone are also clearly present for d(C)12 at acidic pH. An extensive network of CH...O bonds twists the backbone such that multiple through-space vibrational coupling occurs among neighbouring sugar-phosphate residues resulting in unusual VCD signals.

Afferent and efferent phases of allergic contact dermatitis (ACD) can be induced after a single skin contact with haptens: evidence using a mouse model of primary ACD

Allergic contact dermatitis is a T cell-mediated delayed type hypersensitivity reaction that occurs upon hapten challenge in sensitized individuals. The inflammatory response in classical allergic contact dermatitis requires both a sensitization phase and an elicitation phase responsible for the recruitment and activation of specific T cells at the site of hapten skin challenge. Conversely, previously unsensitized patients may develop a "primary allergic contact dermatitis" after the first skin contact with potent contact sensitizers leading to a skin inflammation with all the features of classical allergic contact dermatitis. In this study we used an experimental murine model, referred to as contact hypersensitivity, to study the pathophysiology of primary allergic contact dermatitis and its relationship to classical allergic contact dermatitis. We show that one epicutaneous application of a nonirritant dose of hapten (2,4-dini-trofluorobenzene, fluorescein isothiocyanate) was sufficient to induce an optimal allergic contact dermatitis reaction at the site of primary contact with the hapten without subsequent challenge. As in classical allergic contact dermatitis, the skin inflammation in primary allergic contact dermatitis was mediated by interferon-gamma producing, CD8+ effector T cells that were induced in the draining lymph nodes at day 5 postsensitization and downregulated by CD4+ T cells. Reverse transcription-polymerase chain reaction analysis revealed that the primary allergic contact dermatitis reaction was mediated by a recruitment of CD8+ T cells at the sensitization skin site at day 6 postsensitization. Analysis of the fate of the hapten fluorescein isothiocyanate applied once on the skin revealed its persistence in the epidermis for up to 14 d after skin painting. These results suggest that the development of primary allergic contact dermatitis (i.e., without secondary challenge) is associated with persistence of the hapten in the skin, which allows the recruitment and activation of CD8+ T cells at the site of the single hapten application.

Contact dermatitis II. Clinical aspects and diagnosis

Contact dermatitis (CD) is an altered state of skin reactivity induced by exposure to an external agent. "Eczema" and "dermatitis" are often used synonymously to denote a polymorphic pattern of inflammation of the skin characterized, at least in its acute phase, by erythema, vesiculation and pruritus. Substances that induce CD after single or multiple exposures may be irritant or allergic in nature. The clinical presentation may vary depending on the identity of the triggering agent and the reactivity of the subject, but in all cases the lesions are primarily confined to the site of contact. According to the mechanism of elicitation, the following types of contact reactions may be distinguished: (1) allergic contact dermatitis (ACD); (2) irritant contact dermatitis (ICD); (3) phototoxic and photoallergic contact dermatitis, and (4) immediate type contact reactions. The present review will focus on allergic contact dermatitis. ACD is the clinical presentation of contact sensitivity in humans. The pathophysiology of the contact sensitivity reaction has been reviewed in a preceding issue of this journal [1].

Cytotoxicity is mandatory for CD8(+) T cell-mediated contact hypersensitivity

Contact hypersensitivity (CHS) is a T cell-mediated skin inflammation induced by epicutaneous exposure to haptens in sensitized individuals. We have previously reported that CHS to dinitrofluorobenzene in mice is mediated by major histocompatibility complex (MHC) class I-restricted CD8(+) T cells. In this study, we show that CD8(+) T cells mediate the skin inflammation through their cytotoxic activity. The contribution of specific cytotoxic T lymphocytes (CTLs) to the CHS reaction was examined both in vivo and in vitro, using mice deficient in perforin and/or Fas/Fas ligand (FasL) pathways involved in cytotoxicity. Mice double deficient in perforin and FasL were able to develop hapten-specific CD8(+) T cells in the lymphoid organs but did not show CHS reaction. However, they did not generate hapten-specific CTLs, demonstrating that the CHS reaction is dependent on cytotoxic activity. In contrast, Fas-deficient lpr mice, FasL-deficient gld mice, and perforin-deficient mice developed a normal CHS reaction and were able to generate hapten-specific CTLs, suggesting that CHS requires either the Fas/FasL or the perforin pathway. This was confirmed by in vitro studies showing that the hapten-specific CTL activity was exclusively mediated by MHC class I-restricted CD8(+) T cells which could use either the perforin or the Fas/FasL pathway for their lytic activity. Thus, cytotoxic CD8(+) T cells, commonly implicated in the host defence against tumors and viral infections, could also mediate harmful delayed-type hypersensitivity reactions.

[Physiopathology of eczema]

Eczema is a skin inflammatory reaction mediated by antigen-specific T cells. Two main disorders belong to this group: contact dermatitis and atopic dermatitis. The pathophysiological mecanisms involved in both disorders are similar and include, at the cellular level, three elements: the antigen (hapten or environmental antigen), antigen-presenting cells belonging to the group of dendritic cells and antigen-specific T cells. The Langerhans cell responsible for antigen handling and presentation to specific T cells appears to play a central role for the generation of the inflammatory reaction.

Dual role of dendritic cells in the induction and down-regulation of antigen-specific cutaneous inflammation

We have previously reported that contact sensitivity (CS) to dinitrofluorobenzene (DNFB) in C57BL/6 mice was mediated by MHC class I-restricted CD8+ T cells and down-regulated by MHC class II-restricted CD4+ T cells. In this study, we analyzed the contribution of dendritic cells (DC) in the induction of these two T cell subsets endowed with opposite functions. Hapten-pulsed skin- and bone marrow-derived DC, obtained from either normal C57BL/6 mice or from MHC class II (I+ II-) and MHC class I (I- II+)-deficient mice, were tested for their ability to prime normal mice for CS to dinitrofluorobenzene. Expression of MHC class I molecules by transferred DC was mandatory both for the induction of CS and for the generation of hapten-specific CD8+ T cells in lymphoid organs. I+ II- DC were as potent as I+ II+ DC in priming for CS, demonstrating that activation of effector CD8+ T cells can occur independently of CD4+ T cell help. I- II+ DC could not immunize for CS, although they could sensitize for a delayed-type hypersensitivity reaction to protein Ags. Moreover, I- II+ DC injected simultaneously with cutaneous sensitization down-regulated the inflammatory response, suggesting that hapten presentation by MHC class II molecules could prime regulatory CD4+ T cells. These results indicate that DC can present haptenated peptides by both MHC class I and class II molecules and activate Ag-specific CD8+ effector and CD4+ regulatory T cell subsets, concurrently and independently.

Suboptimal non-inflammatory concentrations of haptens may elicit a contact sensitivity reaction when used as a mix

Contact dermatitis is a cutaneous inflammatory reaction mediated by hapten-specific T cells. We used a murine model to investigate the contact sensitivity reaction elicited by different concentrations (optimal and suboptimal) of the haptens DNFB and oxazolone applied singly or in combination. The simultaneous application of DNFB and oxazolone at optimal concentrations (0.2% and 0.4% respectively) did not significantly increase the ear swelling response induced by each of the allergens when applied singly. No contact sensitivity response was observed when the haptens were tested individually at subthreshold concentrations (0.05% and 0.1% respectively). However, mixing the 2 molecules at the same concentrations gave rise to a clinical contact sensitivity reaction. The simultaneous application of the haptens at a 2 x higher, but still suboptimal concentrations (0.1% and 0.2% respectively), elicited an inflammatory response that was significantly greater than the responses elicited by either of the haptens when applied separately. These results suggest that a "false-positive" reaction to a mix may reveal a genuine sensitization to the constituents.

In vitro primary sensitization of hapten-specific T cells by cultured human epidermal Langerhans cells--a screening predictive assay for contact sensitizers

BACKGROUND

The need to develop predictive tests which could identify potential allergens has been recognized for many years. There is as yet no accepted in vitro method for the assessment of contact sensitizers.

OBJECTIVE

We have tested the ability of a range of contact allergens to induce in vitro primary sensitization of autologous T cells.

METHOD

T-cell proliferation induced by haptens using 2-day cultured human Langerhans cells as antigen-presenting cell was assessed by 3H thymidine incorporation. Antigen specific stimulation was calculated as stimulation indexes.

RESULTS

Strong allergens induced in vitro a primary T-cell response in all (trinitrophenyl, TNP: 13/13) or in the majority (fluorescein isothiocyanate, FITC: 7/10) of experiments. An irritant, sodium dodecyl sulfate (SDS), failed to generate a significant T-cell proliferation in any of the experiments (0/10). We obtained a significant lymphoproliferative response to weak sensitizers only in a limited number of experiments: (coumarin: 1/12, citronellal: 0/10, hydroxycitronellal: 2/8). p-Phenylenediamine (PPDA), a prohapten and highly sensitizing chemical in vivo, generated primary sensitization in vitro in only one of six experiments, while Bandrowski's base (BB), a metabolization product of PPDA induced a significant T-cell response in all six experiments.

CONCLUSION

The present in vitro model allows discrimination between two groups of substances: strong contact sensitizers (TNP, FITC, BB) on the one hand and weak sensitizers (coumarin, citronellal and hydroxycitronellal) and irritants (SDS) on the other hand. It could be used as a screening in vitro assay to eliminate strong contact allergens before further predictive animal tests have to be performed.

In vitro T cell response to staphylococcal enterotoxin B superantigen in chronic plaque type psoriasis

Recent studies have demonstrated the important role of CD4+ T cells in the pathophysiology of psoriasis. One of the current hypotheses is that triggering of the psoriatic inflammatory process could be secondary to CD4+ T cell activation by bacterial superantigens in the skin. In this study, IL-2-derived T cell lines were recovered from the blood and the skin of 4 patients with chronic plaque type psoriasis and of 2 patients with allergic contact dermatitis (ACD). Blood and skin T cell lines were tested for their ability to proliferate in vitro to staphylococcal enterotoxin B (SEB) presented by MHC class II expressing antigen-presenting cells. The results showed a significantly higher SEB-induced T cell proliferation in skin T cell lines as compared to blood T cell lines in 3 out of 4 psoriatic patients and in one of the 2 ACD patients. No difference between the skin and blood T cells for their response to phytohemagglutinin was observed. Furthermore the blood T cell lines from both patients and control individuals responded equally well to SEB. Thus psoriatic skin T cell lines were characterized by an enrichment in SEB-responding T cells. Since similar enhancement of SEB-responsive T cells was occasionally found in ACD patients, we propose that SEB could be an environmental factor associated with rather than responsible for psoriatic inflammation.

Dissociation of allergenic and immunogenic functions in contact sensitivity to para-phenylenediamine

Contact sensitivity to para-phenylenediamine (PPD) is a frequent delayed-type hypersensitivity resulting in contact dermatitis. The aim of the present study, conducted in 16 patients allergic to PPD (as assessed by a positive patch test), was to get better insight into the mechanism of T-cell activation in PPD contact sensitivity. PPD was unable to induce significant proliferation of T cells from a first set of 9 patients. In 7 further patients, lymphocyte proliferation was assessed using PPD and 2 PPD metabolites, namely Brandrowski's base (BB) and benzoquinone (BQ). BB specifically stimulated T-cell proliferation in a dose-dependent fashion in all 7 patients whereas BQ, like PPD, was ineffective. The peripheral blood mononuclear cells (PBMC) of 8 PPD nonallergic individuals did not respond to either PPD, BB or BQ. We concluded from this study that: (1) the immunogenic hapten in PPD hypersensitivity is not PPD itself, and (2) BB might be the oxidative derivative of PPD endowed with T-cell-activating properties. Further support to this statement was provided by the observation that a T cell line derived from PBMC of a PPD-allergic patient in the presence of PPD responded to BB but not to PPD. Our in vitro results suggest that PPD is a prohapten which when applied on the skin is metabolized and converted into products (such as BB) which are the immunogenic haptens able to activate specific T cells.

Changing patterns of contact sensitivity in Sofia

1237 patients with contact sensitization were patch tested five times with the standard patch test series at 3-year intervals. The study was carried out during the period 1975-1987. The results point out the increasing significance of the most common allergens in the industrially developed countries: potassium dichromate, isopropylaminodiphenylamine, formalin, p-phenylenediamine and nickel sulfate.