Assessing Restoration Effects on River Hydromorphology Using the Process-based Morphological Quality Index in Eight European River Reaches

The Morphological Quality Index (MQI) and the Morphological Quality Index for monitoring (MQIm) have been applied to eight case studies across Europe with the objective of analyzing the hydromorphological response to various restoration measures and of comparing the results of the MQI and MQIm as a morphological assessment applied at the reach scale, with a conventional site scale physical-habitat assessment method. For each restored reach, the two indices were applied to the pre-restoration and post-restoration conditions. The restored reach was also compared to an adjacent, degraded reach. Results show that in all cases the restoration measures improved the morphological quality of the reach, but that the degree of improvement depends on many factors, including the initial morphological conditions, the length of the restored portion in relation to the reach length, and on the type of intervention. The comparison with a conventional site scale physical-habitat assessment method shows that the MQI and MQIm are best suited for the evaluation of restoration effects on river hydromorphology at the geomorphologically-relevant scale of the river reach.

New tools for the hydromorphological assessment and monitoring of European streams

Hydromorphological stream assessment has significantly expanded over the last years, but a need has emerged from recent reviews for more comprehensive, process-based methods that consider the character and dynamics of the river with greater accuracy. With this as a focus, a series of hydromorphological tools have been developed and/or further extended in Europe within the context of the REFORM (REstoring rivers FOR effective catchment Management) project. The aim of this paper is to present the set of REFORM hydromorphological assessment methods and, based on some examples of their application, to illustrate and discuss their synergic use, specific features, limitations and strengths. This assessment and monitoring includes three tools: the Morphological Quality Index (MQI), the Morphological Quality Index for monitoring (MQIm), and the Geomorphic Units survey and classification System (GUS). These tools constitute the assessment phase of an overall multi-scale, process-based hydromorphological framework developed in REFORM. The MQI is aimed at an assessment, classification and monitoring of the current morphological state; the MQIm aims at monitoring the tendency of morphological conditions (enhancement or deterioration); the GUS provides a characterization, classification and monitoring of geomorphic units. A series of examples are used to illustrate the potential range of application, including: (i) an assessment of morphological conditions; (ii) an assessment of the morphological effects of restoration projects; (iii) an evaluation of the geomorphic impacts of interventions for risk mitigation; and (iv) an integrated use of MQI and GUS to assess and characterise morphological conditions. Finally, some of the main features, strengths and peculiarities of the three hydromorphological tools are discussed with the support of examples of their application.

Intraoperative radiotherapy (IORT) impairs surgical wound-stimulated breast cancer cell invasion

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Background: Risk of local recurrence after complete excision of breast cancer is higher in the area around the original tumor, suggesting that wound healing may be implicated. Methods: We collected blood samples (BS) before surgery and wound fluid (WF) in the 24 hours after breast conserving surgery from 50 patients. Twenty five of these patients were also treated with TARGeted Intraoperative radioTherapy (TARGIT, 20Gy to tumor bed surface in one session), immediately after the surgical excision. The ability of the BS and WF to stimulate growth and motility of a panel of normal and mammary carcinoma cells was studied. A proteomic approach was used to analyze the expression pattern of WF and BS. Results: We assayed five cell lines in a transwell based assay using individual patient BS and wound fluids WF as potential chemo-attractants. WF strongly attracted cells from all 5 types of breast cancer cell lines that we tested including MDA- MB 231, MCF-7, MDA-MB 453, T47D and SKBR-3. The WF attracted the cells better than both the respective BS. Importantly, in all tested cell lines TARGIT significantly impaired the ability of WF to attract cancer cells (p=0.03 MDA-MB 231 and MCF-7. p=0.01 for MDA-MB 453, and SKBR-3). Moreover, while BS did not stimulate 3D motility over the control WF strongly stimulated 3D movement of MDA-MB 231 and MDA-MB- 453 cells. This stimulatory effect was abrogated in the WF taken from patients who had received TARGIT (p=0.01 for MDA-MB 231 and p<0.0001 for MDA-MB 453). Similar results were obtained when cell proliferation was evaluated using the same cell lines and BS or WF samples. Finally, proteomics analyses demonstrated that TARGIT modifies the expression levels of several key proteins involved in tumor cell growth and dissemination. Conclusion: TARGIT delivered to the tumor bed alters the cytokines and growth factors expression patterns in the surgical wound and abrogates its stimulatory effect on cancer cell growth and motility. This novel mechanism of action of radiotherapy could partly explain the very low recurrence rates found in large pilot studies of this technique and open new avenues for peri-operative therapies.

No significant financial relationships to disclose.

Intraoperative radiotherapy impairs breast cancer cell motility induced by surgical wound fluid

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Background: Most recurrences after breast conserving surgery for cancer occur in the tissues around the original tumour. Wound-fluid has been shown to induce proliferation of breast carcinoma cells. We investigated whether intraoperative radiotherapy (IORT) using the targeted intraoperative radiotherapy (Targit) technique changes the effect of surgical wound fluid on the behaviour of breast cancer cells. Methods: Preoperative peripheral blood serums (A) and wound fluid (B) (first 24 hours’s drainage) from 30 unselected patients undergoing breast conserving surgery with (14) or without (16) IORT using the Targit technique was collected, processed and stored at −80°C. The breast carcinoma cell lines (MDA-MB231, MDA-MB-45 and SKBR-3) were used to evaluate the activity of A and B on cell proliferation (MTT-FACS analysis) and motility (chemotaxis) and invasion (Matrigel). Results: Wound fluid stimulated cell proliferation, cell motility and cell invasion significantly more than the preoperative serum from the same patient. Targit did not influence the effect of wound fluid on cell proliferation. However, Targit abrogated the effect wound fluid on cell motility and cell invasion. Conclusions: This work demonstrates that wound fluid after surgery for breast cancer stimulates cancer cell growth and motility. Targit appears to significantly abrogate the effect on cancer cell migration and invasion. This outcome may confer more benefits than could be expected from the tumoricidal activity of radiotherapy, and may stimulate the development of novel peri-operative treatments directed at compensating the possible harmful effects of surgery.

No significant financial relationships to disclose.

p27(kip1) functional regulation in human cancer: a potential target for therapeutic designs

The mitotic cell cycle is a tightly regulated process that ensures the correct division of one cell into two daughter cells. Progress along the different phases of the cell cycle is positively regulated by the sequential activation of a family of serine-threonine kinases called CDKs (Cyclin Dependent Kinases). Their activity is counteracted by small proteins known as CDK inhibitors (CKI) that ensure the correct timing of CDK activation in the different phases of the cell cycle. The present review will deal with the role of one of this CKI, p27(kip1), in human cancer, focusing in particular on the mechanisms underlying its functional inactivation in tumor cells. p27(kip1) protein downregulation is usually achieved by proteasomal degradation and is often correlated to a worse prognosis in several types of human cancers, resulting in the reduction of disease free and overall survival. More recently, it has been proposed that p27(kip1) protein, rather than degraded, can be functionally inactivated. The mechanisms and the implications of these two types of p27(kip1) deregulation will be discussed and some potential therapeutic approaches targeting p27(kip1) functions will be proposed.

Regulation of Id2 gene expression by the type 1 IGF receptor and the insulin receptor substrate-1

The Id family of helix-loop-helix proteins is known to be involved in the proliferation and differentiation of several types of cells. The type 1 IGF receptor (IGF-IR) induces either proliferation or differentiation in 32D cells, a murine hemopoietic cell line, depending on the availability of the appropriate substrates for the receptor. We have previously reported that the IGF-IR regulates the expression of the Id2 gene in 32D cells. We now show that the IGF-IR controls the increase in Id2 gene expression through at least three pathways. These three pathways originate from the tyrosine residue at 950, a domain in the C-terminus, and the activation of the insulin receptor substrate-1 (IRS-1) by the receptor. IRS-1 is the preponderant signal, and its effect on Id2 gene expression requires a functional phosphotyrosine binding domain. With wild-type IRS-1, Id2 gene expression is increased, even in those cells that express IGF-I receptors defective in Id2 signaling. Rapamycin, an inhibitor of p70(S6K), a downstream effector of IRS-1 signaling, partially inhibits (but does not completely abrogate) the increase in Id2 gene expression. A mutant IRS-1 with a deletion of the Pleckstrin domain is as effective as wild-type IRS-1 in up-regulating Id2 gene expression. In addition, it seems to increase the stability of p70(S6K). Our results indicate that the IGF-IR regulates Id2 gene expression through different pathways. At least in 32D cells, increased Id2 gene expression seems to correlate more with inhibition of differentiation than with proliferation.

The role of the insulin receptor substrate-1 in the differentiation of rat hippocampal neuronal cells

H19-7/IGF-IR cells are rat hippocampal cells expressing a human IGF-I receptor, which differentiate to a neuronal phenotype when stimulated by IGF-I at 39 degrees C. H19-7/IGF-IR cells have low levels of expression of insulin receptor substrate-l (IRS-1), a major substrate of the IGF-IR. IGF-I induces serine-phosphorylation and down-regulation of the endogenous IRS-1 upon differentiation of H19-7/IGF-IR cells. The profound influence of IRS-1 on differentiation of H19-7/IGF-IR cells was confirmed by transfecting these cells with a plasmid expressing mouse IRS-1. Over-expression of wild type IRS-1 in H19-7/IGF-IR cells abolishes IGF-I-induced differentiation at 39 degrees C. A mutant of IRS-1 lacking the PTB domain loses the ability to inhibit the differentiation program. H19-7/IGF-IR/IRS-1 cells at 39 degrees C show a stronger and prolonged activation of Akt, when compared to H19-7/IGF-IR cells. The role of Akt in the inhibition of the differentiation program was confirmed by using the inhibitor of Class I PI3 kinases LY29400, which restores IGF-I-induced differentiation of H19-7/IGF-IR/IRS-1 cells. H19-7/IGF-IR/IRS-1 cells show a strong reduction in MAP kinases signaling, which is related to the superactivation of Akt. This was confirmed by expressing in H19-7/IGF-IR cells a constitutively active Akt, which inhibited MAP kinases activation in these cells. These experiments confirm the importance of MAPK in the mechanism of IGF-I-mediated differentiation of H19-7/IGF-IR cells

Regulation of Id gene expression by type I insulin-like growth factor: roles of Stat3 and the tyrosine 950 residue of the receptor

Id proteins are known to play important roles in the proliferation and differentiation of many cell types. The type 1 insulin-like growth factor receptor (IGF-IR), activated by its ligand, induces the differentiation of 32D IGF-IR cells, a murine hematopoietic cell line, expressing a human IGF-IR. Expression in 32D IGF-IR cells of a dominant negative mutant of Stat3 (DNStat3) inhibits IGF-I-mediated differentiation. DNStat3 causes a dramatic increase in Id2 gene expression. This increase, however, is IGF-I dependent and is abrogated by a mutation at tyrosine 950 of the IGF-IR. These results indicate that in 32D cells, the IGF-IR regulates the expression of the Id2 gene and that this regulation is modulated by both positive and negative signals. Our results also suggest that in this model, Id2 proteins influence the differentiation program of cells but are not sufficient for the full stimulation of their proliferation program.

Regulation of Id2 gene expression by the insulin-like growth factor I receptor requires signaling by phosphatidylinositol 3-kinase

The Id proteins play an important role in proliferation, differentiation, and tumor development. We report here that Id gene expression can be regulated by the insulin-like growth factor I receptor (IGF-IR), a receptor that also participates in the regulation of cellular proliferation and differentiation. Specifically, we found that the IGF-IR activated by its ligand was a strong inducer of Id2 gene expression in 32D murine hemopoietic cells. This activation was not simply the result of cellular proliferation, as Id2 gene expression was higher in 32D cells stimulated by IGF-I than in cells exponentially growing in interleukin-3. The up-regulation of Id2 gene expression was largely dependent on the presence of insulin receptor substrate-1, a major substrate of the IGF-IR and a potent activator of the phosphatidylinositol 3-kinase (PI3K) pathway. The role of PI3K activity in the up-regulation of Id2 gene expression by the IGF-IR was confirmed by different methods and in different cell types. In 32D cells, the up-regulation of Id2 gene expression by the PI3K pathway correlated with interleukin-3 independence and inhibition of differentiation.

Efficient in vitro and in vivo gene regulation of a retrovirally delivered pro-apoptotic factor under the control of the Drosophila HSP70 promoter

We have developed a self-inactivating retroviral vector system with an internal, inducible Drosophila HSP70 promoter. This vector system delivers the desired transgene into cells rapidly and efficiently. It generates mixed populations of transduced cells where the transgene is inducible, and does not require the isolation of specific clones. Since the transgene is not expressed (or poorly expressed) at the restrictive condition (34 degrees C), mixed populations can be selected in which tumor suppressors or other inhibitory genes can be strongly induced upon changing the conditions (39 degrees C or the plant amino acid L-canavanine). This retroviral vector should be very useful for the expression of sequences that are poorly tolerated by cells, and is also active in animals.

Retinoic acid induces neuronal differentiation of embryonal carcinoma cells by reducing proteasome-dependent proteolysis of the cyclin-dependent inhibitor p27

Retinoic acid (RA) treatment of embryonal carcinoma cell line NTERA-2 clone D1 (NT2/D1) induces growth arrest and terminal differentiation along the neuronal pathway. In the present study, we provide a functional link between RA and p27 function in the control of neuronal differentiation in NT2/D1 cells. We report that RA enhances p27 expression, which results in increased association with cyclin E/cyclin-dependent kinase 2 complexes and suppression of their activity; however, antisense clones, which have greatly reduced RA-dependent p27 inducibility (NT2-p27AS), continue to synthesize DNA and are unable to differentiate properly in response to RA as determined by lack of neurite outgrowth and by the failure to modify surface antigens. As to the mechanism involved in RA-dependent p27 upregulation, our data support the concept that RA reduces p27 protein degradation through the ubiquitin/proteasome-dependent pathway. Taken together, these findings demonstrate that in embryonal carcinoma cells, p27 expression is required for growth arrest and proper neuronal differentiation.

Key role of the cyclin-dependent kinase inhibitor p27kip1 for embryonal carcinoma cell survival and differentiation

Hexamethylen-bisacetamide (HMBA) represents the prototype of a group of hybrid polar compounds, which induce differentiation in a variety of transformed cells including human embryonal carcinoma cells. Therefore, HMBA has been used in the differentiation therapy of cancer for patients with both hematological and solid malignancies. Upon HMBA treatment, the embryonal carcinoma cell line NTERA-2 clone D1 (NT2/D1) accumulates in G1 and undergoes terminal differentiation. Here we demonstrate that growth arrest and differentiation of NT2/D1 cells induced by HMBA involve increased expression of the cyclin-dependent kinase inhibitor p27, enhanced association of p27 with cyclin E/CDK2 complexes and suppression of kinase activity associated to cyclin E/CDK2 (but not to cyclin D3/CDK4). When HMBA differentiation was induced in the presence of p27 antisense oligonucleotides, NT2/D1 cells failed to arrest growth properly and, in parallel with the reduction of the anti-apoptotic Bcl-2 gene expression, cells underwent massive programmed cell death. Conversely, constitutive expression of p27 into NT2/D1 cells induced a marked reduction in the growth potential of these cells and partially reproduced HMBA-induced modification of surface antigen expression (down-regulation of SSEA-3 expression and up-regulation of VINIS-53 expression). Expression of p21 induced growth arrest but not differentiation. Likewise, inhibition of CDK2 by transfection of a dominant negative CDK2 in NT2/D1 cells or treatment with the kinase inhibitor olomucine induced growth arrest but not differentiation. Therefore, we propose that p27 represents a crucial molecule in HMBA signaling that cannot be replaced by p21. Furthermore, the results obtained with CDK2 inhibitors demonstrate that the block of CDK2 activity is sufficient for growth arrest but not for cell differentiation and suggest that, at least in these cells, growth arrest and differentiation are regulated by two overlapping but different pathways.

Overexpressed cyclin D3 contributes to retaining the growth inhibitor p27 in the cytoplasm of thyroid tumor cells

The majority of thyroid carcinomas maintain the expression of the cell growth suppressor p27, an inhibitor of cyclin-dependent kinase-2 (Cdk2). However, we find that 80% of p27-expressing tumors show an uncommon cytoplasmic localization of p27 protein, associated with high Cdk2 activity. To reproduce such a situation, a mutant p27 devoid of its COOH-terminal nuclear-localization signal was generated (p27-NLS). p27-NLS accumulates in the cytoplasm and fails to induce growth arrest in 2 different cell lines, indicating that cytoplasm-residing p27 is inactive as a growth inhibitor, presumably because it does not interact with nuclear Cdk2. Overexpression of cyclin D3 may account in part for p27 cytoplasmic localization. In thyroid tumors and cell lines, cyclin D3 expression was associated with cytoplasmic localization of p27. Moreover, expression of cyclin D3 in thyroid carcinoma cells induced cytoplasmic retention of cotransfected p27 and rescued p27-imposed growth arrest. Endogenous p27 also localized prevalently to the cytoplasm in normal thyrocytes engineered to stably overexpress cyclin D3 (PC-D3 cells). In these cells, cyclin D3 induced the formation of cytoplasmic p27-cyclin D3-Cdk complexes, which titrated p27 away from intranuclear complexes that contain cyclins A-E and Cdk2. Our results demonstrate a novel mechanism that may contribute to overcoming the p27 inhibitory threshold in transformed thyroid cells.

Modulation of in vivo growth of thyroid tumor-derived cell lines by sense and antisense vascular endothelial growth factor gene

Vascular endothelial growth factor A (VEGF) is a potent mitogen for endothelial cells in vitro and promotes neo-angiogenesis in vivo. VEGF overexpression occurs in most human malignancies including thyroid carcinomas in which elevated VEGF expression is associated with a high tumorigenic potential. To investigate the role of VEGF in angiogenesis associated with development of thyroid carcinomas, we constitutively expressed VEGF121 into a poorly tumorigenic cell line (NPA) expressing minimal levels of endogenous VEGF. Here we report that VEGF overexpressing NPA cells showed the same growth potential as untransfected NPA in vitro but formed well-vascularized tumors when injected subcutaneously into nude mice with markedly reduced latency compared to parental cells. A complementary approach was to suppress VEGF expression in a highly tumorigenic anaplastic cell line (ARO) by the transfection of an antisense construct. Antisense-transfected ARO cells expressed reduced constitutive levels of VEGF, showed the same growth potential as untransfected ARO cells in vitro and formed small tumors characterized by minimal vascularization, extensive necrosis and longer latency compared to parental or vector-transfected ARO cells in vivo. Finally, we investigated the expression of both VEGF tyrosine kinase receptors (Flt-1 and Flk-1/KDR) in tumor specimens by RT - PCR. Expression of (Flt-1 and Flk-1/KDR) was low in tissue specimens derived from NPA tumors, but was found enhanced in NPA VEGF tumors; conversely, the expression of VEGF receptors was high in tissue specimens derived from ARO tumors but was decreased in tumors derived from VEGF depleted ARO cells. These results clearly demonstrate that VEGF indirectly promotes the growth of thyroid tumors by stimulating angiogenesis.

Regulation of thymosin beta10 expression by TSH and other mitogenic signals in the thyroid gland and in cultured thyrocytes

OBJECTIVE

To investigate the expression of thymosin beta10 - a small conserved acidic protein involved in the inhibition of actin polymerization - in human and experimental thyroid goiters as well as the regulation exerted by TSH on thymosin beta10 expression in thyroid follicular cells both in vivo and in vitro.

DESIGN

To this aim, we have used 5 bioptic specimens from patients affected by thyroid goiter, a well known experimental model of thyroid goitrogenesis (rat fed with the drug propylthiouracil) and a cultured rat thyroid cell line (PC Cl 3 cells) as a model system.

RESULTS

We report that the mRNA expression of thymosin beta10 is markedly enhanced in human goiters compared with normal thyroid. In vivo results showed that the steady-state level of thymosin beta10 mRNA is up-regulated in the thyroid gland of propylthiouracil-fed rats in parallel with follicular cell proliferation: iodide administration to goitrous rats, which induced a marked involution of thyroid hyperplasia, reduced the mRNA level of thymosin beta10. Finally, in vitro studies showed that in cultured rat thyrocytes, the expression of thymosin beta10 mRNA is induced in a time- and dose-dependent manner by the activation of pathways which are mitogenic for thyroid cells (i.e. the protein kinase (PK) A and PKC pathways).

CONCLUSION

Taken together, the findings reported here demonstrate that thymosin beta10 expression is regulated by extracellular signals that stimulate growth of thyroid cells both in vitro and in vivo, and suggest a role for this protein in thyroid diseases characterized by proliferation of follicular cells.

Protein tyrosine phosphatase-eta expression is upregulated by the PKA-dependent and is downregulated by the PKC-dependent pathways in thyroid cells

We have recently reported the isolation of a rat cDNA encoding a receptor-type tyrosine phosphatase, which appears to be a marker of thyroid differentiation. To elucidate the molecular mechanisms underlying r-PTPeta expression in normal thyroid cells both in vitro and in vivo, we investigated the regulation of r-PTPeta expression in cultured thyrocytes (the rat cell line PC Cl 3) and in an animal model of TSH-dependent thyroid goitrogenesis. In vitro studies showed that mRNA expression of r-PTPeta in thyroid cells is induced in a time- and dose-dependent manner by the activation of growth- and differentiation-linked PKA pathways (TSH and forskolin), whereas it is down-regulated by the activation of the proliferative dedifferentiating PKC-dependent transduction pathway (TPA). However, the regulation of r-PTPeta expression by TSH and TPA, respectively, is observed only in normal thyroid cells, but is lost in transformed thyroid cells. In vivo studies with thiouracil-fed rats demonstrated that increased serum levels of TSH up-regulated r-PTPeta mRNA expression in parallel with the stimulation of thyroid growth and function. The reduction of blood TSH levels due to iodide refeeding to goitrous rats determined a marked down-regulation of r-PTPeta expression, in parallel with involution of thyroid hyperplasia. Taken together these results demonstrate that the phosphatase r-PTPeta is regulated by the two main thyroid regulatory pathways and suggest that it may play an important role in the growth and differentiation of thyroid cells.

The quantification of patch test responses: a comparison between echographic and colorimetric methods

Patch testing is widely used both for clinical and experimental purposes. Although the clinical grading employed routinely is of practical value, the lack of objectivity makes it unsuitable for research purposes and dose-response analysis studies. Instrumental measuring techniques have been applied to patch test evaluation, because they enable objective quantification of different biophysical aspects of the inflammatory reaction by means of a continuous assessment scale, providing data suitable for statistical analysis. In order to compare the colorimetric and echographic methods for the evaluation of reactions of different intensity, we performed patch tests with 5% nickel sulfate on the flexor aspect of the forearm in 120 nickel-sensitive patients. Clinical and instrumental measurements were performed at 72 h. Numerical values corresponding to instrumental measurements were compared to the positivity degree, as assessed clinically. Whereas echographic parameters, expressing the intensity of oedema and inflammatory infiltration, enabled a distinction between +, +2 and +3 reactions, colorimetric a* values, describing erythema, failed to distinguish between +2 and +3 reactions. Thus, the use of ultrasound is advisable for the quantification of skin reactions of great intensity, whereas the colorimetric method could be usefully employed for dose-response studies assessing minimal eliciting concentrations of allergens, and for the evaluation of clinically undetectable reactions.

Objective assessment of the minimal irritant reaction induced by a 70% solution of glycolic acid

BACKGROUND/AIMS

Glycolic acid has become a very popular cutaneous improving agent, but, despite its increasing employment, its biophysiological effects on the skin have not been adequately examined. Recently, we described subclinical skin damage induced by a 70% solution of glycolic acid applied on forearm skin by means of non-invasive measuring techniques. In the present study we instrumentally assessed the cutaneous effects induced by a glycolic acid minimal irritant dose on the volar aspect of the right forearm.

METHODS

Twenty subjects, seventeen women and three men, aged 16 to 56, were tested with 40 nl of a 70% solution of glycolic acid applied on one volar forearm area until a clincally evident cutaneous reaction occurred. Visual scoring, TEWL measurement, skin colour, capacitance and echographic recordings were performed before the beginning of the experiment and 30 min and 3, 24, 48 and 72 h after glycolic acid removal. The echo-graphic recordings were carried out using a 20 MHz B scanner (Dermascan C), and then were processed by dedicated software based on segmentation procedures. Two amplitude intervals were selected for the elaboration of the images, the first marking the hyporeflecting areas of the dermis, the second highlighting both the hyperreflecting parts of the epidermis and the lower dermis, separately.

RESULTS

Mean application-time before the appearance of minimal inflammatory skin reactions was 25±7 min. Clinical evaluation was confirmed by the analysis of the colorimetric parameter a*. TEWL and capacitance values showed a marked increase, reaching their maximum at 30 min after solution removal, followed by a progressive decrease. Values of both parameters were statistically significant for up to 48 h. The elaboration of echographic images by a low amplitude interval showed dermal edema more pronounced at 30 min and 24 h, while by highlighting hyperreflecting areas an evident reduction of the entry echo for up to 3 h and a prolonged decrease of the reflectivity of the lower dermis were observable.

CONCLUSION

Our data demonstrate that despite the persistence of higher TEWL values, glycolic acid induced irritation causes a prolonged increase in capacitance that corresponds to modifications in epidermal reflectivity. Epidermal alterations are associated with dermal edema, as evaluated by ultrasound.

A quantitative description of echographic images of sclerotic skin in patients with systemic sclerosis, as assessed by computerized image analysis on 20 MHz B-scan recordings

The aim of our study was to find image descriptors enabling the characterization of sclerotic skin and its differentiation from normal skin, in order to find an objective method for the assessment of skin involvement in systemic sclerosis (SSc). Echographic evaluations were carried out using a 20 MHz B-scanner, on 18 female patients with SSc and on 20 healthy women serving as controls, at 3 different skin sites (forehead, cheek and back of the hand). Images were processed by a program, based on segmentation procedures and object description, employing 5 different amplitude bands and the following parameters: 1) the extension of image areas marked by amplitude bands of interest, 2) the percentage of the image surface reflecting within a homogeneous amplitude band, 3) the number of objects composing the image, 4) the average object size, and 5) the "density" of the objects. At all 3 skin sites, marked differences in the echostructure of the tissue between patients with SSc and the controls were observable. In SSc patients forehead skin appeared thinner and more echogenic, with smaller hypo-reflecting objects and greater hyper-reflecting areas; cheek skin showed an increase in intermediate-high amplitude components, with greater and more numerous hyper-reflecting objects, and smaller and less numerous hypo-reflecting ones; the skin on the back of the hand was thicker, less echogenic, with large hypo-reflecting areas and small hyper-reflecting objects. By image processing these parameters were numerically described. Values referring to sclerotic skin significantly differed from those of normal skin. This echographic procedure is proposed as a method representing a first step towards the quantification of the spontaneous course of SSc and of response to therapy.

Skin reactivity to sodium lauryl sulfate in patients with respiratory atopy

BACKGROUND

No literature data are available on the skin reactivity of patients with respiratory atopy alone.

OBJECTIVE

Our purpose was to assess skin reactivity to detergents in patients with allergic asthma, rhinitis, or both.

METHODS

The skin of the volar aspect of the forearm of 19 subjects with allergic asthma or rhinitis (or both) was challenged with a single exposure to 0.5% sodium lauryl sulfate. The skin response was evaluated by transepidermal water loss (TEWL), capacitance, and echogenicity measurements. Results were compared with those obtained in 19 patients with atopic dermatitis (AD) and 20 healthy subjects.

RESULTS

In patients with AD preexposure TEWL values were higher than in healthy subjects, whereas capacitance values were lower. In this patient group, postexposure TEWL, capacitance, and echogenicity values showed more pronounced variations than in healthy subjects. Conversely, in patients with allergic asthma or rhinitis (or both), both baseline and postexposure TEWL, capacitance, and echogenicity values were similar to those in healthy subjects.

CONCLUSION

Patients with respiratory atopy without AD do not have the functional abnormalities characteristic of skin affected by AD, either under baseline conditions or after exposure to sodium lauryl sulfate.

Ultrasound description and quantification of irritant reactions induced by dithranol at different concentrations. A comparison with visual assessment and colorimetric measurements

Dithranol (D) is used as a therapeutic topical agent to treat psoriasis, although it produces inflammation and staining of skin and clothing. D-induced irritation has been evaluated by visual scoring and by bioengineering techniques, evidencing modifications of the inflammatory parameters, but no alterations of the skin barrier. The aim of our study was to evaluate the irritant reactions induced by D using ultrasound, and to compare the B-scanning data with visual assessments and colorimetric measurements. 13 healthy women underwent 2, 3-h patch tests with, respectively, 0.02% and 0.1% D in white petrolatum and 1 24-h patch test with 2% sodium lauryl sulfate (SLS). For assessing skin reactions, clinical judgement, colorimetry and echography were employed. Echographic images were evaluated by skin thickness measurements and segmentation procedures, using an 0-30 interval, marking the hyporeflecting areas in the dermis, and a 201-255 interval, assessing the hyperreflecting components of the image (both epidermal and dermal). In all subjects, D produced uniform reactions, the intensity varying according to concentration. Both echographic parameters of inflammation (skin thickness and 0-30 areas) showed an increase at all times of assessment. The 201-255D/0-30 pixel ratio, describing the distribution of dermal edema, indicated that strong inflammatory reactions, such as those caused by the application of 0.1% D, are accompanied by edema in the lower portion of the dermis. Finally, in contrast to SLS reactions, where a 24-h reduction in epidermal reflectivity was observable, D reactions appeared with an accentuation of the 201-255 epidermal band at 24-96-h examinations.

Pre-treatment of nickel test areas with sodium lauryl sulfate detects nickel sensitivity in subjects reacting negatively to routinely performed patch tests

A fair % of patients with a clinical history of nickel allergy show negative patch test results. To improve the response rate to NiSO4 5% pet. patch tests, a testing procedure utilizing pre-treatment of the test area by a 24-h application of sodium lauryl sulfate (SLS) was introduced. 46 women with a clinical history of nickel sensitivity, who exhibited negative reactions to nickel sulfate 5% pet. patch tests, were studied. Patients underwent 6 patch tests on adjacent sites on the volar surface of the forearms. 4 patch tests were performed with a 72-h application of 40 mg nickel sulfate 5% pet. While 1 of these patch tests served as control, 3 test areas underwent 24-h pre-treatment with 40 microliters SLS, 1 with 0.1% and 2 with 0.5% solution. To evaluate differences in the reactivity to SLS plus nickel sulfate related to the site on the forearm, 0.5% SLS pre-treatment was performed both on a proximal and on a distal test site. At the 72-h evaluation, 19 subjects out of 46 showed positive reactions to nickel sulfate 5% pet. at skin sites pre-treated with 0.1% SLS, whereas 23 patients reacted positively at 0.5% SLS pre-treated areas. Echographic values of skin thickness and of hypo-echogenic dermal areas at positive pre-treated nickel test areas were higher than at control test areas, confirming the clinical evidence of an increased response to NiSO4 after SLS pre-treatment. The inflammatory reaction, as evaluated clinically and echographically, was much higher at distal skin areas (0.1% SLS and distal 0.5% SLS) than at proximal 0.5% SLS ones.

Computerized evaluation of pigmented skin lesion images recorded by a videomicroscope: comparison between polarizing mode observation and oil/slide mode observation

BACKGROUND/AIMS

It has now been established that ELM significantly improves the clinical diagnosis of pigmented skin lesions, particularly when associated with image analysis on digital pictures. Besides surface microscopes, so called "videomicroscopes" are nowadays commercially available. Thanks to their practicality and to their reasonable price and small volume, they could be usefully employed by general practitioners or peripheral dermatologists in their practice. The aim of our study was to evaluate the usefulness and the handiness of a videomicroscope provided with polarized light, and to compare images recorded in the polarizing mode to those of the same lesions recorded after application of oil and a glass slide.

METHODS

114 images of benign pigmented skin lesions were recorded both in polarizing mode and in oil/slide mode observation. Digital images were then analyzed by means of a dedicated software, evaluating 34 different parameters.

RESULTS

The instrument is easy to handle and the acquisition of images is simple and quick. Polarizing mode observation enables the recognition of subsurface structures, like pigment network and capillaries. Red and blue components in the images tend to be more pronounced, when images are acquired by the polarizing system, whereas green components are prominent in oil images. Values referring to dark areas are also higher for oil images. However, the 2 observation modes provide digital images, whose values, in most cases, do not differ statistically.

CONCLUSION

Videomicroscopes are cheap, space saving, and enable a quick examination of skin areas to be imaged. The possibility of a rapid switch from surface to subsurface polarizing mode observation, makes the examination procedure even faster. Our data demonstrate that polarizing mode observation and recording can be employed as a basis for clinical and computerized epiluminescence, particularly in situations, where a rapid screening of numerous patients and lesions is necessary.

Pretreatment of the test area with 1-day occlusion improves the response rate to NiSO4 5% pet. patch tests in subjects with a positive history of nickel allergy

A group of 58 women, aged 18 to 51 years, with a clinical history of nickel allergy, who exhibited equivocal or negative reactions to nickel sulfate 5% pet. patch tests performed on the skin of the back, were recruited consecutively from the patch test clinic from September 1993 to June 1994. In order to improve the response rate to NiSO4 5% pet. patch tests, a testing procedure utilizing pretreatment of the test area by 1-day (24-h) occlusion was introduced. Patients underwent 2 patch tests on adjacent sites of the volar surface of both forearms. 3 of the patch tests were performed with 40 mg nickel sulfate 5% pet., whereas a control test was carried out by occluding with an empty chamber. 2 of the nickel sulfate test sites were pretreated with 1-day occlusion performed with an empty chamber. A visual grading system and echographic measurement were used to quantify the responses 30-40 min after patch test removal. Echographic evaluations were carried out using a 20 MHz B-scanner. Measurement of skin thickness and determination of the hypoechogenic dermal area, both considered to be parameters of inflammation, were used to evaluate the intensity of the allergic reaction. At the 3-day (72-h) evaluation, 19 subjects out of 58 clearly showed positive reactions to nickel sulfate 5% pet. at pre-occluded skin sites. Moreover, values of skin thickness and of 0-30 areas at positive pre-occluded nickel test areas were higher in respect to control test areas, confirming clinical evidence of increased response to NiSO4 after occlusion.

Prostacyclin (PGI2) synthase is a constitutively expressed enzyme in human endothelial cells

Biogenesis of prostanoids is under the control of some polypeptide growth factors. Cytosolic phospholipase A2, a form specific for arachidonic acid containing phospholipids, is activated by a translocation mechanism regulated by growth factors, while prostaglandin H synthase isoforms are induced de novo in several cell types. No information is available as far as PGI2 synthase is concerned. Human umbilical vein endothelial cells were cultured under conditions favoring proliferation or differentiation or capillary-like network formation in the presence of collagen gels. Basic fibroblast growth factor (bFGF 0.5-4 ng/ml) was used as a mitogen, interleukin-1 alpha (IL-1 alpha 10-60 UI/ml) as a differentiating agent, and prostacyclin (PGI2) biosynthesis was evaluated. Under the first condition, basal PGI2 production was unaffected while, in the presence of IL-1 alpha, a marked stimulation of PGI2 synthesis was observed. It is known that IL-1 alpha is a potent inducer of PGH synthase, while it is not known whether PGI2 synthase is also induced. Two lines of evidence indicate that PGI2 synthase is a constitutively expressed not inducible enzyme: (a) proliferating nonproducing cells when added with PGH2 produce an amount of PGI2 not different from the amount produced by cells stimulated with IL-1 alpha; (b) under this condition PGI2 synthase was immunodetectable either by immunofluorescence detected by confocal microscopy or by ELISA and, on microsomes isolated from endothelial cells, by Western blotting. It is concluded that the limiting step in the conversion arachidonate-PGI2 is represented solely by the level of PGH synthase. These results strongly suggest, but do not prove, the constitutive nature of the enzyme. The final demonstration requires the availability of a probe to detect mRNA level, a trial we are carrying out at the moment.

Possible involvement of prostaglandin H synthase-1 induction in the differentiation of U-937 cells

The promyelocytic human cell line U937, cultured in the presence of TPA and/or vit. D3, differentiates to monocytes and to macrophage-like cells. A potent stimulus for differentiation is represented also by colony stimulating factor-1 (CSF-1). Since this factor is a strong inducer of PGH synthase in human monocytes, we have investigated whether this event may be connected to the differentiation of U937. We have found that TPA, in the presence of serum, increased the production of thromboxane B2 (TXB2) 4-5 fold, while DMSO, which induced differentiation to neutrophils, was not active. Here we report studies indicating that the effect of protein and RNA synthesis inhibitors on prostanoid production, in cells incubated in the presence of CSF-1 (or FCS), can be correlated with an inductive event carried out by the growth factor, as demonstrated by the use of Western and Northern blotting procedures. However, while in human monocytes PGH-s and its mRNA are absent in controls and are expressed at high levels in CSF-1 stimulated cells, in U937 cells exposed to TPA, PGH-s mRNA was clearly detected by Northern blots, but its translation product was expressed at low level, and cells generated low amounts of TXA2 (13% of maximal production). After incubation with CSF-1 (or FCS) mRNA levels were only slightly modified, but large amounts of TXA2 accumulated in the medium. We have interpreted these findings by suggesting that CSF-1 is capable not only of regulating the expression of the gene encoding PGHs, but also of acing translationally to regulate the expression of its mature mRNA.

Post-transcriptional regulation of thromboxane A2 synthase in U937 cells

Translation of mRNAs is a process usually tightly coupled to transcription of genes. However, there are examples of mRNA species which accumulate without being translated. Some mRNAs present in oocytes and ferritin mRNA are the most studied models. Studying the biogenesis of thromboxane A2 (TXA2) in the promonocytic line U937, we have noted that in proliferating cells high levels of TXA2 synthase mRNA are detectable by Northern blot, whereas no TXA2 could be recovered in the medium. This has been explained on the basis of Western blot experiments: TXA2 synthase was not detectable in proliferating cells, while a band of about 55 kd appears after treatment with the differentiating agent TPA. Immunofluorescence detection by confocal microscopy was in agreement with Immunoblot results. Thus, in U937 cells, TPA behaves as a regulator of translation of TXA2 synthase mRNA. We have further observed that the induced enzyme in U937 cells has many characteristics in common with the human monocytic enzyme: a long half life (> 24 hrs), a marked stability during catalysis and similar Km and Vmax values. Thus, U937 cells are a good model to study the mechanism by which a mRNA is efficiently translated only after differentiation has been triggered.

Thromboxane A2 synthase activity in platelet free human monocytes

Soon after platelets, the highest amounts of thromboxane A2 (TXA2) can be detected in human monocytes activated by serum. Using platelet-free human monocytes, we have shown that foetal calf serum (FCS) induces prostaglandin H synthase (PGH synthase) after 16 h of incubation, as shown by the use of transcriptional inhibitors and Western blotting. The effect of serum can be in part mimicked by recombinant colony stimulating factor-1 (hr CSF-1). It is not known whether the limiting step leading from arachidonate to TXA2 is represented solely by the level of PGH synthase or also by the level of TXA2 synthase. We approached this problem by using a Western blot specific for the enzyme, as well as by using PGH2 as substrate. The results show that TXA2 synthase is constitutively expressed in monocytes, i.e., its levels were high soon after their isolation, and similar to those observed after 24 h of incubation with serum. However TXA2 failed to be synthesized until at least 3 h of incubation, and the pattern of synthesis was dependent on the kinetics of PGH synthase induction. In any condition in which TXA2 synthase was immunodetectable, using PGH2 as substrate a high rate of conversion to TXB2 could be detected. Experiments with actinomycin D and cycloheximide indicate that the half-life of TXA2 synthase was longer than 16 h, therefore much longer than that of PGH synthase, that the gene coding for it is fully active in resting monocytes, and that the conversion of arachidonate to TXA2 induced by serum or CSF-1 is dependent solely on the de novo synthesis of PGH synthase.