Brain angiotensin enhances dopaminergic cell death via microglial activation and NADPH-derived ROS

Angiotensin II (AII) plays a major role in the progression of inflammation and NADPH-derived oxidative stress (OS) in several tissues. The brain possesses a local angiotensin system, and OS and inflammation are key factors in the progression of Parkinson's disease. In rat mesencephalic cultures, AII increased 6-OHDA-induced dopaminergic (DA) cell death, generation of superoxide in DA neurons and microglial cells, the expression of NADPH-oxidase mRNA, and the number of reactive microglial cells. These effects were blocked by AII type-1 (AT1) antagonists, NADPH inhibitors, or elimination of glial cells. DA degeneration increased angiotensin converting enzyme activity and AII levels. In rats, 6-OHDA-induced dopaminergic cell loss and microglial activation were reduced by treatment with AT1 antagonists. The present data suggest that AII, via AT1 receptors, increases the dopaminergic degeneration process by amplifying the inflammatory response and intraneuronal levels of OS, and that glial cells play a major role in this process.

Nipple sparing mastectomy with nipple areola intraoperative radiotherapy: one thousand and one cases of a five years experience at the European institute of oncology of Milan (EIO)

In order to reduce mutilation, nipple-areola complex (NAC) conservation can be proposed for the treatment of breast cancer when mastectomy is indicated. To reduce the risk of retro areolar recurrence, a novel radiosurgical treatment combining subcutaneous mastectomy with intraoperative radiotherapy (ELIOT) is proposed. One thousand and one nipple sparing mastectomies (NSM) were performed from March 2002 to November 2007 at the European institute of oncology (EIO), for invasive carcinoma in 82% of the patients and in situ carcinoma in 18%. Clinical complications, aesthetic results, oncological and psychological results were recorded. A comparison was performed between the 800 patients who received ELIOT and the 201 who underwent delayed one-shot radiotherapy on the days following the operation. The median follow up time was 20 months (range 1-69) for a follow up performed in 83% of the patients. The NAC necrosed totally in 35 cases (3.5%) and partially in 55 (5.5%) and was removed in 50 (5%). Twenty infections (2%) were observed and 43 (4.3%) prostheses removed. The median rate of the patients for global cosmetic result on a scale ranging from 0 (worst) to 10 (excellent) was 8. Evaluation by the surgeon in charge of the follow-up gave a similar result. Only 15% of the patients reported a partial sensitivity of the NAC. Of the fourteen (1.4%) local recurrences, ten occurred close to the tumour site, all far from the NAC corresponding to the field of radiation. No recurrences were observed in the NAC. In a group of patients characterized by a very close free margin under the areola, no local recurrence was observed. Overall, 36 cases of metastases and 4 deaths were observed. No significant outcome difference was observed between the 800 patients receiving intraoperative radiotherapy (ELIOT) and the 201 patients receiving delayed irradiation.

Evaluation of fat grafting safety in patients with intraepithelial neoplasia: a matched-cohort study

BACKGROUND

Fat grafting is widely carried out in breast cancer patients to improve quality in breast reconstruction. Recently, in vitro and animal studies have questioned the role of adipose tissues in cancer development.

DESIGNS

Matched-cohort study. We analysed: (i) 59 intraepithelial neoplasia patients who had undergone lipofilling, with no recurrence between primary surgery and lipofilling. (ii) A control group of 118 matched patients (two controls per lipofilling patient) with the corresponding recurrence-free intervals. Both groups were also matched for main cancer criteria. A local event (LE) was the primary end point, with follow-up starting from the baseline.

RESULTS

Median follow-up was 63 and 66 months from surgery, and 38 and 42 from baseline, for the lipofilling and control groups, respectively; the 5-year cumulative incidence of LE was 18% and 3% (P = 0.02). Ki-67 was the significant factor in univariate survival analysis. A subgroup analysis showed that lipofilling increased the risk of LE in women <50 years, with high grade neoplasia, Ki-67 ≥ 14 or who had undergone quadrantectomy.

CONCLUSION

Higher risk of LE was observed in intraepithelial neoplasia patients following lipofilling. Although further studies are required to validate our conclusions, patients belonging to this subgroup should be informed of these results and the potential risks.

Nipple-sparing mastectomy: risk of nipple-areolar recurrences in a series of 579 cases

BACKGROUND

When the conservative treatment is not recommended, Nipple Sparing Mastectomy (NSM) is proposed more and more frequently for the surgical treatment of breast cancer. The risk of local recurrence behind the nipple areolar complex (NAC) is the main limiting factor of the NSM procedure. To minimize such risk, we proposed in 2002 a intraoperative radiotherapy of the preserved NAC.

PATIENTS AND METHODS

From March 2002 to November 2006, 579 cases (in 570 patients) of NSM were performed for carcinoma. The median follow up time was 19 months (Range: 1-60). The subcutaneous mastectomy was performed through an incision removing a portion of the skin overlying the tumour. An extemporaneous histological examination was performed on the retroareolar glandular tissue. If the histology was positive the patient was not considered eligible. Then an intraoperative radiotherapy with electrons (ELIOT) of 16 Gy in one shot was delivered on the NAC area. An immediate breast reconstruction was done using implants in most cases and in several cases a musculocutaneous flaps, usually in large breast. The number of local recurrences was recorded and the correlation between their occurrence and the clinical and histological criteria were analysed using the Gray test statistical method in a competing framework.

RESULTS

In 516 cases the negative retroareolar frozen section biopsy was confirmed by the final histology, while in 63 cases, the final histology showed foci of carcinoma. Seven out of these 63 cases underwent a secondary NAC removal. In the 56 cases which preserved areolas we did not observe any local recurrence after 19 months follow up. The probability of retro areola positive histology increases with the tumour size. and was not related to the nodal status. The rate of local relapses was 0.9% per year. We didn't find any significant difference in the local relapse rate according to different patient's and tumour's features. Most relapses were located close to the tumour bed but never in the NAC area.

CONCLUSION

Our study confirms that the local recurrence rate in the NSM completed with local radiotherapy on the NAC is not higher than the usual rate observed in the literature and the preservation of the NAC does not increase the risk. The absence of local recurrence in the region where a portion of glandular tissue has been purposely preserved is a good argument in favour of ELIOT.

Mechanism of 6-hydroxydopamine neurotoxicity: the role of NADPH oxidase and microglial activation in 6-hydroxydopamine-induced degeneration of dopaminergic neurons

Cell death induced by 6-hydroxydopamine (6-OHDA) is thought to be caused by reactive oxygen species (ROS) derived from 6-OHDA autooxidation and by a possible direct effect of 6-OHDA on the mitochondrial respiratory chain. However, the process has not been totally clarified. In rat primary mesencephalic cultures, we observed a significant increase in dopaminergic (DA) cell loss 24 h after administration of 6-OHDA (40 micromol/L) and a significant increase in NADPH subunit expression, microglial activation and superoxide anion/superoxide-derived ROS in DA cells that were decreased by the NADPH inhibitor apocynin. Low doses of 6-OHDA (10 micromol/L) did not induce a significant loss of DA cells or a significant increase in NADPH subunit expression, microglial activation or superoxide-derived ROS. However, treatment with the NADPH complex activator angiotensin II caused a significant increase in all the latter. Forty-eight hours after intrastriatal 6-OHDA injection in rats, there was still no loss of DA neurons although there was an increase in NADPH subunit expression and NADPH oxidase activity. The results suggest that in addition to the autooxidation-derived ROS and the inhibition of the mitochondrial respiratory chain, early microglial activation and NADPH oxidase-derived ROS act synergistically with 6-OHDA and constitute a relevant and early component of the 6-OHDA-induced cell death.

Angiotensin type-1-receptor antagonists reduce 6-hydroxydopamine toxicity for dopaminergic neurons

Angiotensin II activates (via type 1 receptors) NAD(P)H-dependent oxidases, which are a major source of superoxide, and is relevant in the pathogenesis of several cardiovascular diseases and certain degenerative changes associated with ageing. Given that there is a brain renin-angiotensin system and that oxidative stress is a key contributor to Parkinson's disease, we investigated the effects of angiotensin II and angiotensin type 1 (AT(1)) receptor antagonists in the 6-hydroxydopamine model of Parkinson's disease. Rats subjected to intraventricular injection of 6-hydroxydopamine showed bilateral reduction in the number of dopaminergic neurons and terminals. Injection of angiotensin alone did not induce any significant effect. However, angiotensin increased the toxic effect of 6-hydroxydopamine. Rats treated with the AT(1) receptor antagonist ZD 7155 and then 6-hydroxydopamine (with or without exogenous administration of angiotensin) showed a significant reduction in 6-hydroxydopamine-induced oxidative stress (lipid peroxidation and protein oxidation) and dopaminergic degeneration. Dopaminergic degeneration was also reduced by the NAD(P)H inhibitor apocynin. Angiotensin may play a pivotal role, via AT(1) receptors, in increasing the oxidative damage of dopaminergic cells, and treatment with AT(1) antagonists may reduce the progression of Parkinson's disease.

Angiotensin-converting enzyme inhibition reduces oxidative stress and protects dopaminergic neurons in a 6-hydroxydopamine rat model of Parkinsonism

It is now established that the brain possesses a local renin-angiotensin system and that angiotensin II exerts multiple actions in the nervous system, including regulation of striatal dopamine release. Furthermore, angiotensin activates NADPH-dependent oxidases, which are a major source of superoxide, and angiotensin-converting enzyme inhibitors, commonly used in the treatment of hypertension and chronic heart failure, have shown antioxidant properties in several tissues. Oxidative stress is a key contributor to the pathogenesis and progression of Parkinson's disease. In the present study, we treated rats with intraventricular injections of the dopaminergic neurotoxin 6-hydroxydopamine and subcutaneous injections of the angiotensin-converting enzyme inhibitor Captopril to study the possible neuroprotective effect of the latter on the dopaminergic system and on 6-hydroxydopamine-induced oxidative stress. Rats treated with Captopril and 6-hydroxydopamine showed significantly less reduction in the number of dopaminergic neurons (i.e., immunoreactive to tyrosine hydroxylase) in the substantia nigra and in the density of striatal dopaminergic terminals than 6-hydroxydopamine-lesioned rats not treated with Captopril. In addition, Captopril reduced the levels of major oxidative stress indicators (i.e., lipid peroxidation and protein oxidation) in the ventral midbrain and the striatum of 6-hydroxydopamine-lesioned rats. Our results suggest that angiotensin-converting enzyme inhibitors may be useful for treatment of Parkinson's disease and that further investigation should focus on the neuroprotective capacity of these compounds.

Nitronyl and imino nitroxides: improvement of Ullman's procedure and report on a new efficient synthetic route

The synthesis of nitronyl and imino nitroxides has been reexamined with the aim of both increasing yields and of offering opportunities for new structures. The conditions for the formation of 2,3-bis(hydroxyamino)-2,3-dimethylbutane, the key intermediate of Ullman's route, have been carefully studied, and a new procedure is proposed, which affords the free base in a very pure form and up to 60% yield. Full characterization of this intermediate including an X-ray crystal structure is presented. An alternative synthetic route through 2,3-diamino-2,3-dimethylbutane and the corresponding imidazolidines which bypasses the delicate synthesis of the bis(hydroxyamino) compound is described. It is shown that 3-chloroperbenzoic acid is an effective oxidant for the transformation of adequately substituted imidazolidines into nitronyl nitroxides, which are obtained in high yield. An illustration of the potentialities of this new route, a new nitronyl nitroxide with two ethyl substituents in positions 4 and 5 of the imidazoline ring, is reported. The scope and limitations of the two routes are discussed.

Involvement of CDSP 32, a drought-induced thioredoxin, in the response to oxidative stress in potato plants

In animal cells, yeast and bacteria, thioredoxins are known to participate in the response to oxidative stress. We recently identified a novel type of plant thioredoxin named CDSP 32 for chloroplastic drought-induced stress protein of 32 kDa. In the present work, we measured comparable increases in the glutathione oxidation ratio and in the level of chlorophyll thermoluminescence, a specific marker for thylakoid lipid peroxidation in Solanum tuberosum plants subjected to drought or oxidative treatments (photooxidative stress, gamma irradiation and methyl viologen spraying). Further, substantial accumulations of CDSP 32 mRNA and protein were revealed upon oxidative treatments. These data show for the first time in plants the induction of a thioredoxin by oxidative stress. We conclude that CDSP 32 may preserve chloroplastic structures against oxidative injury upon drought.

Biological control of plant pathogens: advantages and limitations seen through the case study of Pythium oligandrum

The management of certain plant beneficial microorganisms [biological control agents (BCAs)] seems to be a promising and environmental friendly method to control plant pathogens. However, applications are still limited because of the lack of consistency of BCAs when they are applied in the field. In the present paper, the advantages and limitations of BCAs are seen through the example of Pythium oligandrum, an oomycete that has received much attention in the last decade. The biological control exerted by P. oligandrum is the result of a complex process, which includes direct effects through the control of pathogens and/or indirect effects mediated by P. oligandrum, i.e. induction of resistance and growth promotion. P. oligandrum antagonism is a multifaceted and target fungus-dependent process. Interestingly, it does not seem to disrupt microflora biodiversity on the roots. P. oligandrum has an atypical relationship with the plant because it rapidly penetrates into the root tissues but it cannot stay alive in planta. After root colonisation, because of the elicitation by P. oligandrum of the plant-defence system, plants are protected from a range of pathogens. The management of BCAs, here P. oligandrum, is discussed with regard to its interactions with the incredibly complex agrosystems.

Molecular characterization of CDSP 34, a chloroplastic protein induced by water deficit in Solanum tuberosum L. plants, and regulation of CDSP 34 expression by ABA and high illumination

We previously described the accumulation of a 34 kDa thylakoid protein, named CDSP 34 for chloroplastic drought-induced stress protein, in Solanum tuberosum plants subjected to water deficit. A full-length CDSP 34 cDNA has been isolated and we report here that mature CDSP 34 is highly similar to two chromoplastic proteins, fibrillin from Capsicum annuum and CHRC (for chromoplast protein C) from Cucumis sativus, components of carotenoid-accumulating structures. Northern and Western analyses showed that both CDSP 34 transcript and protein accumulated from early stages of water deficit. In water-stressed tomato plants, similar increases in the CDSP 34-related transcript amount were noticed in wild-type and ABA-deficient flacca mutant, but protein accumulation was observed only in wild-type, suggesting a posttranscriptional role of ABA in CDSP 34 synthesis regulation. Substantial increases in CDSP 34 transcript and protein abundances were also observed in potato plants subjected to high illumination. The CDSP 34 protein is proposed to play a structural role in stabilizing stromal lamellae thylakoids upon osmotic or oxidative stress.

Towards a better understanding of the magnetic interactions within m-phenylene alpha-nitronyl imino nitroxide based biradicals

An extensive investigation of the magnetic properties of three series of biradicals (bis-nitronyl nitroxides diNN-R, bis-imino nitroxides diIN-R and mixed INNN-R, where R is either hydrogen, a triple bond or trimethylsilylacetylenic group) has been carried out to give clear values of the intramolecular interactions through the m-phenylene coupling unit with alpha-nitronyl nitroxides (NN) or alpha-imino nitroxides (IN). An EPR study of the molecules in the isolated state is validated by ab initio calculations, which show the respective influence of spin polarisation and molecular conformation on the singlet-triplet gaps. All these results indicate that the triplet state is the ground state for such biradicals, except when the imidazolyl cycles are orthogonal to the phenyl ring. The magnetic properties of the biradicals in the solid state can be rationalised by examination of the short contacts produced between the ONCNO and ONCN groups. EPR studies on single crystals of the H-substituted series have confirmed the presence of a structural distortion for diNN-H whereas diIN-H and INNN-H do not exhibit such a peculiarity. The magnetic behaviour of diIN-H is described well by a four-spins model, with a strong intermolecular antiferromagnetic interaction of -90 K, whereas in the case of the two other compounds, a supplementary contact involves more complex interactions between the dimers. The compound diNN-tmsa exhibits a ferromagnetic intermolecular interaction of +11 K within the dimers, and this could be attributed to the relative disposition of the imidazolyl rings. Compound diNN-tr reveals a chain-like behaviour, whereas diIN-tr shows a predominant antiferromagnetic interaction within the dimers. The values for the intramolecular interactions in the solid state are in good agreement with those found for the isolated molecules.

Over-expression of a pepper plastid lipid-associated protein in tobacco leads to changes in plastid ultrastructure and plant development upon stress

Proteins homologous to fibrillin, a pepper plastid lipid-associated protein involved in carotenoid storage in fruit chromoplasts, have been recently identified in leaf chloroplasts from several species and shown to be induced upon environmental stress. To further investigate the role of the protein, transgenic Nicotiana tabacum plants over-expressing fibrillin using a constitutive promoter were generated. Transgenics grown under standard light intensities (300 micromol photons m-2 sec-1) were found to contain substantial amounts of fibrillin in flowers and leaves. In leaves, the protein was immunolocalized within chloroplasts in both stromal and thylakoid subfractions. No change was noticed in thylakoid structures from transgenics, but chloroplasts contained an increased number of plastoglobules organized in clusters. In petals, leucoplasts were also found to contain more agglutinated plastoglobules. The effects of environmental factors on fibrillin gene expression and protein localization were studied in tobacco leaves. Less fibrillin was present in plants grown under low light intensities, which can be explained by the involvement of a light-dependent splicing step in the control of fibrillin gene expression in leaves. Analysis of protein subfractions from plants subjected to drought or high light showed that both stresses resulted in fibrillin association with thylakoids. Whereas no growth difference between wild-type (WT) and transgenic plants was noticed under low light conditions, transgenics exhibit a longer main stem, enhanced development of lateral stems and accelerated floral development under higher light intensities. These data suggest that fibrillin-related proteins fulfil an important function in plant development in relation to environmental constraints.

Novel square planar copper(II) complexes with imino or nitronyl nitroxide radicals exhibiting large ferro- and antiferromagnetic interactions

This paper reports the synthesis, crystal structures, and magnetic properties of two copper(II) complexes (1, 2) of general formula Cu(tfac)2(radical)2 (tfac = trifluoroacetate; radical = (1) 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (NITPh) or (2) 2-phenyl-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazoline-1- oxyl (IMPh)). They crystallize in the monoclinic P2(1)/n space group with the following parameters: (1) a = 13.212(2) A, b = 9.136(1) A, c = 15.587(2) A, beta = 114.61(1) degrees, Z = 2; (2) a = 11.059(2) A, b = 15.289(1) A, c = 10.694(2) A, beta = 114.20(1) degrees, Z = 2. In both complexes the copper(II) ion is coordinated to two radicals in a slightly distorted square planar surrounding. The copper(II)-radical exchange couplings are antiferromagnetic for the nitronyl nitroxide (NITPh) complex (1) and ferromagnetic in the case of the imino nitroxide (IMPh) analogue (2). The ground state has been found to be a spin-doublet for 1 and the spin-quartet for 2. No thermal population of the highest states has been observed, indicating copper(II)-radical couplings of magnitude of J > 500 cm-1.

Accumulation of plastid lipid-associated proteins (fibrillin/CDSP34) upon oxidative stress, ageing and biotic stress in Solanaceae and in response to drought in other species

Plastid lipid-associated proteins, also termed fibrillin/CDSP34 proteins, are known to accumulate in fibrillar-type chromoplasts such as those of ripening pepper fruit, and in leaf chloroplasts from Solanaceae plants under abiotic stress conditions. It is shown here that treatments generating active oxygen species (high light combined with low temperature, gamma irradiation or methyl viologen treatment) result in potato CDSP34 gene induction and protein accumulation in leaves. Using transgenic tomato plants containing the pepper fibrillin promoter, a significant increase in promoter activity in leaves subjected to biotic stress, namely bacterial infections, was observed. In WT, a higher level of the endogenous fibrillin/CDSP34 protein is also observed after infection by E. chrysanthemi strain 3739. In addition to stress-related induction, a progressive increase in the fibrillin promoter activity is noticed during ageing in various tomato photosynthetic tissues and this increase correlates with a higher abundance of the endogenous protein in WT leaves. It is proposed that a mechanism related to oxidative events plays an essential role in the regulation of fibrillin/CDSP34 genes during stress and also during development. Using a biolistic transient expression assay, the pepper fibrillin promoter is found to be active in various dicot species, but not in monocots. Further, substantially increased levels of fibrillin/ CDSP34 proteins are shown in various dicotyledonous and monocotyledonous plants in response to water deficit.

Ultrastructural and Cytochemical Aspects of the Interaction Between the Mycoparasite Pythium oligandrum and Soilborne Plant Pathogens

ABSTRACT The interaction between the oomycete Pythium oligandrum and various soilborne oomycete and fungal plant pathogens (P. ultimum, P. aphanidermatum, Fusarium oxysporum f. sp. radicis-lycopersici, Verticillium albo-atrum, Rhizoctonia solani, and Phytophthora megasperma) was studied by light and electron microscopy in order to assess the relative contribution of mycoparasitism and antibiosis in the antagonistic process. Scanning electron microscope investigations of the interaction regions showed that structural alterations of all pathogenic fungi and oomycetes (except for Phytophthora megasperma) occurred soon after contact with the antagonist. Light and transmission electron microscope studies of the interaction region between the antagonist and P. ultimum revealed that intimate contact between both partners preceded a sequence of degradation events including aggregation of host cytoplasm and penetration of altered host hyphae. Localization of the host wall cellulose component showed that cellulose was altered at potential penetration sites. A similar scheme of events was observed during the interaction between P. oligandrum and F. oxysporum f. sp. radicis-lycopersici, with the exception that complete loss of host protoplasm was associated with antagonist invasion. The interaction between P. oligandrum and R. solani resulted in an abnormal deposition of a wall-like material at potential penetration sites for the antagonist. However, the antagonist displayed the ability to circumvent this barrier and penetrate host hyphae by locally altering the chitin component of the host hyphal wall. Interestingly, antagonist cells also showed extensive alteration as evidenced by the frequent occurrence of empty hyphal shells. In the case of Phytophthora megasperma, hyphal interactions did not occur, but hyphae of the plant pathogen were damaged severely. At least two distinct mechanisms appear to be involved in the process of oomycete and fungal attack by P. oligandrum: (i) mycoparasitism, mediated by intimate hyphal interactions, and (ii) antibiosis, with alteration of the host hyphae prior to contact with the antagonist. However, the possibility that the antagonistic process may rely on the dual action of antibiotics and hydrolytic enzymes is discussed.

Treatment with the Mycoparasite Pythium oligandrum Triggers Induction of Defense-Related Reactions in Tomato Roots When Challenged with Fusarium oxysporum f. sp. radicis-lycopersici

ABSTRACT The influence exerted by the mycoparasite Pythium oligandrum in triggering plant defense reactions was investigated using an experimental system in which tomato plants were infected with the crown and root rot pathogen Fusarium oxysporum f. sp. radicis-lycopersici. To assess the antagonistic potential of P. oligandrum against F. oxysporum f. sp. radicis-lycopersici, the interaction between the two fungi was studied by scanning and transmission electron microscopy (SEM and TEM, respectively). SEM investigations of the interaction region between the fungi demonstrated that collapse and loss of turgor of F. oxysporum f. sp. radicis-lycopersici hyphae began soon after close contact was established with P. oligandrum. Ultrastructural observations confirmed that intimate contact between hyphae of P. oligandrum and cells of the pathogen resulted in a series of disturbances, including generalized disorganization of the host cytoplasm, retraction of the plasmalemma, and, finally, complete loss of the protoplasm. Cytochemical labeling of chitin with wheat germ agglutinin (WGA)/ovomucoid-gold complex showed that, except in the area of hyphal penetration, the chitin component of the host cell walls was structurally preserved at a time when the host cytoplasm had undergone complete disorganization. Interestingly, the same antagonistic process was observed in planta. The specific labeling patterns obtained with the exoglucanase-gold and WGA-ovomucoid-gold complexes confirmed that P. oligandrum successfully penetrated invading cells of the pathogen without causing substantial cell wall alterations, shown by the intense labeling of chitin. Cytological investigations of samples from P. oligandrum-inoculated tomato roots revealed that the fungus was able to colonize root tissues without inducing extensive cell damage. However, there was a novel finding concerning the structural alteration of the invading hyphae, evidenced by the frequent occurrence of empty fungal shells in root tissues. Pythium ingress in root tissues was associated with host metabolic changes, culminating in the elaboration of structural barriers at sites of potential fungal penetration. Striking differences in the extent of F. oxysporum f. sp. radicis-lycopersici colonization were observed between P. oligandrum-inoculated and control tomato plants. In control roots, the pathogen multiplied abundantly through much of the tissues, whereas in P. oligandrum-colonized roots pathogen growth was restricted to the outermost root tissues. This restricted pattern of pathogen colonization was accompanied by deposition of newly formed barriers beyond the infection sites. These host reactions appeared to be amplified compared to those seen in nonchallenged P. oligandrum-infected plants. Most hyphae of the pathogen that penetrated the epidermis exhibited considerable changes. Wall appositions contained large amounts of callose, in addition to be infiltrated with phenolic compounds. The labeling pattern obtained with gold-complexed laccase showed that phenolics were widely distributed in Fusarium-challenged P. oligandrum-inoculated tomato roots. Such compounds accumulated in the host cell walls and intercellular spaces. The wall-bound chitin component in Fusarium hyphae colonizing P. oligandrum-inoculated roots was preserved at a time when hyphae had undergone substantial degradation. These observations provide the first convincing evidence that P. oligandrum has the potential to induce plant defense reactions in addition to acting as a mycoparasite.

Geographical variation in autonomous self-pollination levels unrelated to pollinator service in Helleborus foetidus (Ranunculaceae)

Autonomous self-pollination may be considered as a mechanism enhancing plant reproductive success when plant access to pollen sources may limit seed production. We have studied the relationship between geographical patterns of variation in pollinator service to Helleborus foetidus and self-pollination ability in three widely spaced regions in the Iberian Peninsula. As could be expected from its early flowering period, pollinator visitation rates to both plants and flowers of H. foetidus were very low at all sites. Pollinator composition remained consistent among regions, but there was significant variation among regions in pollinator service. Despite the low visitation rates, fruit set did not appear to be pollen limited in any of the study areas, which may be explained by the long duration of flowers (up to 20 d). When pollinators were excluded experimentally, fruit set decreased significantly, but substantial levels of self-pollination occurred at all regions. Autonomous self-pollination levels were lowest in the two regions with lowest pollinator service and highest in the region with highest pollinator service. This disagreement between our results and the expectations derived from the reproductive assurance hypothesis may reflect a nonequilibrium situation of the northern H. foetidus populations in relation to their current pollinating environment.

A novel thioredoxin-like protein located in the chloroplast is induced by water deficit in Solanum tuberosum L. plants

By analysing two-dimensional patterns of chloroplastic proteins from Solanum tuberosum, the authors observed the accumulation of a 32-kDa polypeptide in the stroma of plants subjected to water deficit. N-terminus and internal peptides of the protein, named CDSP 32 for chloroplastic drought-induced stress protein, showed no obvious homology with known sequences. Using a serum raised against the protein N-terminus, a cDNA encoding CDSP 32 was cloned by screening an expression library. The deduced mature CDSP 32 protein is 243 amino acids long and displays typical features of thioredoxins in the C-terminal region (122 residues). In particular, CDSP 32 contains a CGPC motif corresponding to a thioredoxin active site and a number of amino acids conferring thioredoxin-type structure. The CDSP 32 C-terminal region was expressed as a fusion protein in Escherichia coli and was shown to possess thioredoxin activity based on reduction assay of insulin disulfide bridges. RNA blot analysis showed that CDSP 32 transcript does not accumulate upon mild water deficit conditions corresponding to leaf relative water contents (RWC) around 85%, but high levels of CDSP 32 transcripts were observed for more severe stress conditions (RWC around 70%). In vivo labelling and immunoprecipitation revealed a substantial increase in CDSP 32 synthesis upon similar stress conditions. Rewatering of wilted plants caused decreases in both transcript and protein abundances. In tomato wild-type plants and ABA-deficient mutants, a similar accumulation of a CDSP 32-related transcript was observed upon water deficit, most likely indicating no requirement for ABA in the regulation of CDSP 32 synthesis. Based on these results, it is proposed that CDSP 32 plays a role in preservation of the thiol: disulfide redox potential of chloroplastic proteins during water deficit.

Oligandrin. A proteinaceous molecule produced by the mycoparasite Pythium oligandrum induces resistance to Phytophthora parasitica infection in tomato plants

A low-molecular weight protein, termed oligandrin, was purified to homogeneity from the culture filtrate of the mycoparasitic fungus Pythium oligandrum. When applied to decapitated tomato (Lycopersicon esculentum Mill. var. Prisca) plants, this protein displayed the ability to induce plant defense reactions that contributed to restrict stem cell invasion by the pathogenic fungus Phytophthora parasitica. According to its N-terminal sequence, low-molecular weight, acidic isoelectric point, ultraviolet spectrum, and migration profile, the P. oligandrum-produced oligandrin was found to share some similarities with several elicitins from other Phytophthora spp. and Pythium spp. However, oligandrin did not induce hypersensitive reactions. A significant decrease in disease incidence was monitored in oligandrin-treated plants as compared with water-treated plants. Ultrastructural investigations of the infected tomato stem tissues from non-treated plants showed a rapid colonization of all tissues associated with a marked host cell disorganization. In stems from oligandrin-treated plants, restriction of fungal growth to the outermost tissues and decrease in pathogen viability were the main features of the host-pathogen interaction. Invading fungal cells were markedly damaged at a time when the cellulose component of their cell walls was quite well preserved. Host reactions included the plugging of intercellular spaces as well as the occasional formation of wall appositions at sites of potential pathogen entry. In addition, pathogen ingress in the epidermis was associated with the deposition of an electron-opaque material in most invaded intercellular spaces. This material, lining the primary walls, usually extended toward the inside to form deposits that frequently interacted with the wall of invading hyphae. In the absence of fungal challenge, host reactions were not detected.

Expression of KS-type dehydrins is primarily regulated by factors related to organ type and leaf developmental stage during vegetative growth

The expression of a gene, designated as DHN10, was analyzed at the protein level in two Solanum species. The DHN10 protein displays some consensus amino acid sequences of dehydrins, termed K- and S-segments. Unlike most dehydrins, both segments occur only in single copies in the DHN10 sequence and the S-segment is at a C-terminal position. Database searches revealed that KS-type dehydrins constitute a specific subclass distributed in dicotyledons and monocotyledons. In Solanum tuberosum L. plants, a high DHN10 abundance was observed under control conditions, particularly in flowers, stems, tubers and young developing leaves. In other Solanaceae and in barley ( Hordeum vulgare L.), the amount of DHN10 was much more elevated in young leaves than in old leaves. DHN10 abundance was investigated in two Solanum species subjected to low temperature or to drought. Under stress conditions, we observed substantially higher protein levels only in mature expanded leaves. These findings clearly indicate that KS-type dehydrins are present at a high level in the absence of stress during vegetative growth and that their expression is primarily regulated by factors related to organ type and to leaf development stage. A potential role for the DHN10 dehydrin during plant development and in tolerance to environmental stress is discussed.

Indigenous bacteria with antagonistic and plant-growth-promoting activities improve slow-filtration efficiency in soilless cultivation

In tomato soilless culture, slow filtration allows one to control the development of diseases caused by pathogenic microorganisms. During the disinfecting process, microbial elimination is ensured by mechanical and biological factors. In this study, system efficacy was enhanced further to a biological activation of filter by inoculating the pozzolana grains contained in the filtering unit with 5 selected bacteria. Three strains identified as Pseudomonas putida and 2 as Bacillus cereus came from a filter whose high efficiency to eliminate pathogens has been proven over years. These 5 bacteria displayed either a plant growth promoting activity (P. putida strains) or antagonistic properties (B. cereus strains). Over the first months following their introduction in the filter, the bacterial colonisation of pozzolana grains was particularly high as compared to the one observed in the control filter. Conversely to Bacillus spp. populations, Pseudomonas spp. ones remained abundant throughout the whole cultural season. The biological activation of filter unit very significantly enhanced fungal elimination with respect to the one displayed by the control filter. Indeed, the 6-month period needed by the control filter to reach its best efficacy against Fusarium oxysporum was shortened for the bacteria-amended filter; in addition, a high efficacy filtration was got as soon as the first month. Fast colonization of pozzolana grains by selected bacteria and their subsequent interaction with F. oxysporum are likely responsible for filter efficiency. Our results suggest that Pseudomonas spp. act by competition for nutrients, and Bacillus spp. by antibiosis and (or) direct parasitism. Elimination of other fungal pathogens, i.e., Pythium spp., seems to differ from that of Fusarium since both filters demonstrated a high efficacy at the experiment start. Pythium spp. elimination appears to mainly rely on physical factors. It is worth noting that a certain percentage of the 5 pozzolana-inoculated bacteria failed to colonise the filter unit and were, thus, driven to the plants by the nutrient solution. Their contribution to the establishment of a beneficial microbial community in the rhizosphere is discussed.

Immediate Breast Reconstruction and High-Dose Chemotherapy

BACKGROUND

Immediate breast reconstruction (IBR) is considered as a safe procedure nowadays, and it can be proposed in the majority of patients requiring a mastectomy. In fact, recent studies have demonstrated that immediate breast reconstruction is not detrimental also to patients with locally advanced breast cancers. However, IBR should be reevaluated in case of locally advanced breast cancer requiring high-dose chemotherapy (HDCT). The aim of this study is to evaluate both the risk of chemotherapy delay due to surgical complications and the risk of late surgical complications related to the association with HDCT. We considered 3 series of 23, 67, and 15 patients requiring a mastectomy at the European Institute of Oncology in Milan. After mastectomy, these groups respectively received an IBR and HDCT, an IBR and conventional chemotherapy, and only HDCT with no IBR.

METHODS

Files of 105 patients who were admitted to our department from October 1999 to January 2002 were reviewed. Twenty-three patients underwent a mastectomy, followed by IBR and HDCT; 67 underwent a mastectomy plus IBR plus conventional CT; and, finally, 15 underwent a mastectomy alone followed by HDCT. The reconstructive techniques performed were 72 permanent prosthesis and 18 temporary expanders. We excluded all patients with IBR by flap (latissimus dorsi or pedicled rectus abdominis) to improve the homogeneity of the sample.

RESULTS

All patients who underwent IBR started high-dose chemotherapy without any delay; the time elapsed between surgery and HDCT is not significantly different for patients with and without IBR (54 versus 60 days, P = 0.13). The early complication rate (before CT) was 2.9% (2 patients with infection). The late complication rate (after CT) was higher for the group that underwent IBR followed by HDCT (39% versus 20%).

CONCLUSION

We did not observe any delay for the administration of high-dose chemotherapy after mastectomy with IBR surgery. The complication rate before HDCT is similar to the complication rates published in the literature. On the contrary, we observed a higher rate of infections (13% versus 0%, P = 0,014) after HDCT than after conventional CT, which can be related to the association with high-dose chemotherapy, inducing a decrease of the immune defenses. These results seems to demonstrate that the association of IBR with HDCT is not detrimental to patients from the oncological point of view, but the impact of HDCT on the reconstruction is more negative. Further studies are needed to verify if this risk exists, although lower, in the association with conventional CT. However, a careful evaluation of the risk of infections should be considered preoperatively, and perioperative contaminations should be carefully prevented.

Characterization of a novel drought-induced 34-kDa protein located in the thylakoids of Solanum tuberosum L. plants

Using two-dimensional electrophoresis and Coomassie Blue staining, the accumulation of a 34-kDa protein (named cdsp 34 for chloroplastic drought-induced stress protein) is shown in the thylakoids of Solanum tuberosum plants subjected to a progressive and reversible water deficit. In-vivo labeling experiments showed an increased synthesis of cdsp 34 from the early stages of drought stress (leaf relative water content around 85%) and throughout the constraint. Sequences of the N-terminal part and of four tryptic-digest peptides did not reveal significant homology between the cdsp 34 protein and other known proteins. Western blotting analysis, using a serum raised against the N-terminal part of cdsp 34, confirmed the accumulation of cdsp 34 in thylakoids upon drought stress. From immunoblot analysis of different chloroplastic subfractions, the cdsp 34 protein appears to be an extrinsic protein preferentially located in unstacked stroma thylakoids. Immunoprecipitation of in-vitro-translated products, as well as Southern analysis, showed that the cdsp 34 protein is nuclear encoded. After rewatering of water-stressed plants, the level of cdsp 34 synthesis was reduced, but remained substantially higher than in control plants. Western analysis showed the persistence of a high amount of cdsp 34 in rewatered plants for at least two weeks. Based on the abundance and on the location of cdsp 34 within thylakoids, a putative role for this novel chloroplastic protein is discussed in relation to the tolerance of the photosynthetic apparatus of higher plants to dehydration.