Freeze-dried human serum albumin improves the adherence and proliferation of mesenchymal stem cells on mineralized human bone allografts

Mineralized scaffolds are widely used as bone grafts with the assumption that bone marrow derived cells colonize and remodel them. This process is slow and often unreliable so we aimed to improve the biocompatibility of bone grafts by pre-seeding them with human mesenchymal stem cells from either bone marrow or dental pulp. Under standard cell culture conditions very low number of seeded cells remained on the surface of freeze-dried human or bovine bone graft or hydroxyapatite. Coating the scaffolds with fibronectin or collagen improved seeding efficiency but the cells failed to grow on the surface until the 18th day. In contrast, human albumin was a very potent facilitator of both seeding and proliferation on allografts which was further improved by culturing in a rotating bioreactor. Electron microscopy revealed that cells do not form a monolayer but span the pores, emphasizing the importance of pore size and microstructure. Albumin coated bone chips were able to unite a rat femoral segmental defect, while uncoated ones did not. Micro-hardness measurements confirmed that albumin coating does not influence the physical characteristics of the scaffold, so it is possible to introduce albumin coating into the manufacturing process of lyophilized bone allografts.

Characterization of polygenic resistance to powdery mildew in tomato at cytological, biochemical and gene expression level

Extensive research in the area of plant innate immunity has increased considerably our understanding of the molecular mechanisms associated with resistance controlled by a dominant resistance gene. In contrast, little is known about the molecular basis underlying the resistance conferred by quantitative trait loci (QTLs). In this study, using the interaction of tomato (Solanum lycopersicum) with Oidium neolycopersici, we compared the cytological, biochemical and molecular mechanisms involved in both monogenic and polygenic resistances conferred by a dominant gene (Ol-1) and three QTLs (Ol-qtls), respectively. Our results showed that the three Ol-qtls jointly confer a very high level of broad-spectrum resistance and that the resistance is associated with both the hypersensitive response and papillae formation, with the hypersensitive response being prevalent. Both H(2)O(2) and callose accumulation, which are coupled with Ol-1-mediated resistance, are also associated with the resistance conferred by Ol-qtls. Further, we analysed the pathogen-induced transcript profiles of near-isogenic lines carrying the three Ol-qtls and the Ol-1 gene. Transcript profiles obtained by cDNA-amplified fragment length polymorphism analysis showed that, on fungal challenge, about 70% of the transcript-derived fragments are up-regulated in both susceptible and resistant genotypes. Most of the sequenced transcript-derived fragments showed homology to genes with functions in defence responses, suggesting that defence-responsive genes responsible for basal defence are involved in both monogenic and polygenic resistances conferred by Ol-1 and Ol-qtls, respectively. Although about 18% of the identified transcript-derived fragments are specific for either monogenic or polygenic resistance, their expression patterns need to be further verified by quantitative reverse transcriptase-polymerase chain reaction.

Increased stability of S-nitrosothiol solutions via pH modulations

S-nitrosothiol (RSNO) solutions represent a valuable source of nitric oxide and could be used as topical vasodilators, but their fast decomposition rate poses a serious obstacle to their potentially widespread therapeutic use. Our aim was to characterize and quantify the effect of pH on S-nitrosothiol formation and decomposition in simple aqueous solutions of S-nitrosoglutathione (GSNO), S-nitroso-N-acetylcysteine (SNAC) and S-nitroso-3-mercaptopropionic acid (SN3MPA). Furthermore, we investigated the effect of storage pH on the stability of GSNO incorporated in poly(ethylene glycol)/ poly(vinyl alcohol) matrices. S-nitrosothiol concentrations were measured spectrophotometrically and laser Doppler scanning method was used to assess dermal blood flow. GSH and NAC solutions reached a complete transformation to nitrosothiols when synthesized using acidic NaNO(2) solution. The initial concentration of all investigated RSNOs decreased more slowly with pH adjusted to mildly basic values (8.4-8.8) for the storage period. Polymer gels of PVA/PEG compositions at mildly basic storage pH further reduced the decomposition rate succeeding to contain 46.8% of the initial GSNO concentration for 25 days. This amount of topically administered GSNO was still capable of increasing the dermal blood flow over 200% in human subjects.

Role of Ca²+-sensitive K+ currents in controlling ventricular repolarization: possible implications for future antiarrhytmic drug therapy

Normal heart function and repolarization of the cardiac action potential (AP) is to a high extent subjective to synchronized activity of sarcolemmal K(+) channels, expressed in both ventricular and atrial myocardium, largely contributing to regulation of the resting potential, the pacemaker activity, and the shape and duration of the AP. Clinical observations and experimental studies in cardiomyocytes and multicellular preparations provided firm evidence for the sensitivity of some major outward K+ currents and the corresponding ion channels to shifts in intracellular Ca(2+) concentration ([Ca(2+)](i)). Direct regulation via interaction between [Ca(2+ )](i) and the channel protein or indirect modulation via Ca(2+ ) signaling pathways of these currents have strong implications to mechanical and electrical performance of the heart, and its physiological adaptation to altered load. It may also lead to severe cardiac dysfunction, if [Ca(2+ )](i) handling is disturbed in a variety of pathological conditions. In this review we attempt to summarize the present state of the topic on two ubiquitous repolarizing K(+) currents (I(to1) and I(K1)) with documented Ca(2+)-sensitivity and critical significance in cellular antiarrhythmic defense, to highlight fields where clue data are missing, and discuss the apparently unsolved "mystery" of the cardiac small conductance Ca(2+ )-activated K(+ ) (SK) channels. We have collected the available information on the known novel, although usually still not enough selective inhibitors and activators of these currents justifying the need for more selective ones. Finally, we emphasize a few related therapeutical perspectives to be considered for future experimental research and particularly in pharmaceutical development.

Stem cell transplantation in an in vitro simulated ischemia/reperfusion model

Stem cell transplantation protocols are finding their way into clinical practice. Getting better results, making the protocols more robust, and finding new sources for implantable cells are the focus of recent research. Investigating the effectiveness of cell therapies is not an easy task and new tools are needed to investigate the mechanisms involved in the treatment process. We designed an experimental protocol of ischemia/reperfusion in order to allow the observation of cellular connections and even subcellular mechanisms during ischemia/reperfusion injury and after stem cell transplantation and to evaluate the efficacy of cell therapy. H9c2 cardiomyoblast cells were placed onto cell culture plates. Ischemia was simulated with 150 minutes in a glucose free medium with oxygen level below 0.5%. Then, normal media and oxygen levels were reintroduced to simulate reperfusion. After oxygen glucose deprivation, the damaged cells were treated with transplantation of labeled human bone marrow derived mesenchymal stem cells by adding them to the culture. Mesenchymal stem cells are preferred in clinical trials because they are easily accessible with minimal invasive surgery, easily expandable and autologous. After 24 hours of co-cultivation, cells were stained with calcein and ethidium-homodimer to differentiate between live and dead cells. This setup allowed us to investigate the intercellular connections using confocal fluorescent microscopy and to quantify the survival rate of postischemic cells by flow cytometry. Confocal microscopy showed the interactions of the two cell populations such as cell fusion and formation of intercellular nanotubes. Flow cytometry analysis revealed 3 clusters of damaged cells which can be plotted on a graph and analyzed statistically. These populations can be investigated separately and conclusions can be drawn on these data on the effectiveness of the simulated therapeutical approach.

The role of mitochondria in direct cell-to-cell connection dependent rescue of postischemic cardiomyoblasts

In this in vitro study we induced ischemic injury on H9c2 rat cardiomyoblasts using the oxygen-glucose deprivation model (OGD). We monitored if the addition of healthy or mitochondria-depleted cells can save OGD treated cells from post-ischemic injury. We were able to significantly improve the surviving cell number of oxidatively damaged H9c2 cells by the addition of healthy cells to the culture. On the contrary, cells with disturbed mitochondria did not increase the number of surviving cells. High-resolution confocal time-lapse imaging also proved that mitochondria are drifting from cell-to-cell through tunneling membrane bridges, however, they do not get into the cytoplasm of the other cell. We conclude that addition of healthy cells to severly injured post-ischemic cardiomyoblasts can rescue them from death during the first 24h after reoxigenation. Grafted cells must maintain their mitochondria in an actively respiring state, and although cell contact is required for the mechanism, neither cell fusion nor organelle transfer occurs. This novel mechanism opens a new possiblity for cell-based cardiac repair in ischemic heart disease.

Human internal thoracic artery grafts exhibit severe morphological and functional damage and spasmic vasomotion due to oxidative stress

Background

The internal thoracic artery (ITA) is the first choice for myocardial revascularization, but atherosclerotic lesions and perioperative vasospasm may still limit its functionality. Oxidative stress via the peroxynitrite – poly-(ADP-ribose) polymerase (PARP) cascade plays an important role in the pathogenesis of impaired vascular tone via endothelial injury. We aimed to investigate and describe the histology, PARP activation and functionality of ITA grafts and to assess the possible beneficial effect of PARP-inhibition.

Material/Methods

ITA specimens from 47 patients (26 men, mean age 66.2±1.7 years) who underwent coronary bypass surgery were processed for histological and immunohistochemical studies for oxidative stress and PARP activation, and were functionally tested with acetylcholine (ACh) and sodium nitroprusside (SNP) with or without PARP inhibition.

Results

The sections showed atherosclerotic alterations and oxidative and nitrosative stress were evidenced by positive 3-nitrotyrosine, 4-hydroxynonenal and PAR stainings. Functionally, 88.1% reacted to K-Krebs, 68.7% exhibited contraction after 1 μM phenylephrine, 29.9% exhibited relaxation to 30 μM Ach, and all precontracted segments relaxed to 30 μM SNP. High amplitude vasomotion was observed in 47.8% of the segments, which could be abolished by the application of 10 μM SNP. Incubation of the preparations with PJ34 did not improve endothelium-dependent vasodilation.

Conclusions

ITA grafts are severely damaged both morphologically and functionally in patients undergoing coronary artery bypass surgery, but PARP inhibition cannot improve their functional characteristics. The topical use of SNP to the ITA during the operation may improve vascular functions by dilating the vessels and eliminating the eventual spasmic vasomotion.

Peach Rusty Spot Is Caused by the Apple Powdery Mildew Fungus, Podosphaera leucotricha

Peach rusty spot, an economically important disease of peach (Prunus persica var. persica), appears as necrotic spots on fruit. The etiology of the disease is still not well understood, although it has long been suspected that the causal agent is the apple powdery mildew pathogen, Podosphaera leucotricha. This work confirmed this hypothesis based on cross-inoculation experiments and analysis of rDNA internal transcribed spacer sequences polymerase chain reaction amplified from rusty spot and peach powdery mildew lesions. Cross-inoculations of apple and peach leaves with P. leucotricha and P. pannosa, the causal agent of peach powdery mildew, showed that (i) young peach fruit, up to 5 cm in diameter, developed symptoms typical of rusty spot following inoculation with P. leucotricha; (ii) leaves of 'Jonagold' apple seedlings developed powdery mildew infections when inoculated by touching young rusty spot lesions to their surfaces; (iii) P. leucotricha sporulated on young peach fruit up to 5 cm in diameter; and (iv) peach leaves and young shoots were not susceptible to P. leucotricha, whereas P. pannosa infected all the green parts of peach. A field experiment revealed that there was only a 2- to 3-week period of time during early peach fruit development when the epidermis was susceptible to P. leucotricha. An outcome of this study is that now a clear distinction can be made between the symptoms caused by P. pannosa and P. leucotricha on peach.

Pathological evidence in support of total mesorectal excision in the management of rectal cancer

BACKGROUND

Pelvic recurrence following conventional rectal resection for cancer is common. Preoperative iradiation has been shown in prospective randomized studies to halve this risk.

AIM

This multiinstitutional study aimed to assess the necesity of total mesorectal excision in rectal cancer.

PATIENTS AND METHOD

Pathological resections from 50 consecutive patients with adenocarcinoma of the rectum within 12 cm of the anal verge who underwent currative resection incorporating total mesorectal excision were examined. The resection specimen was examined by one of two pathologists. Some 50 total mesorectal excision specimens were examined following rectal excision for cancer. Some 38 had total mesorectal excision as a component of a low anterior resection and 12 with abdomino-perineal resection. "Cure" was defined as absence of metastatic disease and the excision of entire macroscopic tumor tissue with negative proximal and distal borders. TME was performed as described by Heald et al. The mesorectum was evaluated for lymph nodes and tumor deposists in three areas: deep to the tumor, in the proximal mesorectum and in the distal mesorectum.

RESULTS

Six patients had Dukes A lesions. Of 21 patients with Dukes B tumors, five had discrete foci of adenocarcinoma in the mesorectum, with no evidence of lymph node metastasis. Dukes C lesions were more heterogeneous, but 12 out of 23 patients had distinct mesorectal deposists in addition to mesorectal node involvement. Circumferential margin involvement was rare, but mesorectal tumor deposits were present in 17 of 44 patients with pT3 tumors, and 23 of 44 had mesorectal nodal involvement. No patient with a pT2 tumor had mesorectal involvement. Failure to excise the mesorectum completely has the potential to leave gross or microscopic residual disease that may in theory predispose to local failure.

CONCLUSION

Total mesorectal excision is necessary to avoid incomplete pathological evaluation of the mesorectum and understaging of rectal cancer.

Nuclear and chloroplast microsatellites show multiple introductions in the worldwide invasion history of common ragweed, Ambrosia artemisiifolia

BACKGROUND

Ambrosia artemisiifolia is a North American native that has become one of the most problematic invasive plants in Europe and Asia. We studied its worldwide population genetic structure, using both nuclear and chloroplast microsatellite markers and an unprecedented large population sampling. Our goals were (i) to identify the sources of the invasive populations; (ii) to assess whether all invasive populations were founded by multiple introductions, as previously found in France; (iii) to examine how the introductions have affected the amount and structure of genetic variation in Europe; (iv) to document how the colonization of Europe proceeded; (v) to check whether populations exhibit significant heterozygote deficiencies, as previously observed.

PRINCIPAL FINDINGS

We found evidence for multiple introductions of A. artemisiifolia, within regions but also within populations in most parts of its invasive range, leading to high levels of diversity. In Europe, introductions probably stem from two different regions of the native area: populations established in Central Europe appear to have originated from eastern North America, and Eastern European populations from more western North America. This may result from differential commercial exchanges between these geographic regions. Our results indicate that the expansion in Europe mostly occurred through long-distance dispersal, explaining the absence of isolation by distance and the weak influence of geography on the genetic structure in this area in contrast to the native range. Last, we detected significant heterozygote deficiencies in most populations. This may be explained by partial selfing, biparental inbreeding and/or a Wahlund effect and further investigation is warranted.

CONCLUSIONS

This insight into the sources and pathways of common ragweed expansion may help to better understand its invasion success and provides baseline data for future studies on the evolutionary processes involved during range expansion in novel environments.

First Report of Oidium longipes as the Causal Agent of Petunia Powdery Mildew in the United Kingdom

In autumn 2009, during a survey of powdery mildews of solanaceous plants in the United Kingdom, petunia (Petunia × hybrida) plants showing typical symptoms of powdery mildew infections were repeatedly collected in East Malling, Rochester, and Sandringham, UK. Leaves, stems, and petals of the collected plants, grown as outdoor ornamentals, were covered by dense, sporulating, white mycelium. Conidia were ellipsoid-cylindrical, measured 20 to 30 × 10 to 15 μm, and were produced in chains. Germ tubes arose from the ends of conidia and terminated in simple, unlobed apices. Some of the conidiophores were extremely long, up to 250 μm, because the second or third cell, or sometimes the foot cell, was up to 105 to 170 μm long. Other conidiophores were shorter, with no exceptionally long cells, but all of them exhibited a few characteristics in common: their width increased from base to top, sometimes enlarging considerably at a particular point of the foot cell, and basal septa were usually located 7 to 30 μm from the point of branching. Hyphal appressoria were nipple shaped. The teleomorph stage was not found. On the basis of these characteristics, the fungus was identified as Oidium longipes, a recently described (4) and little known pathogen of petunia and other solanaceous plants (1,3). To support the identification of this fungus, DNA was extracted from conidia collected with sterile brushes from single leaves collected in Sandringham, East Malling, and Rochester with a Qiagen DNeasy Plant Kit (Qiagen, Hilden, Germany), and the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA was amplified and determined as described in Jankovics et al. (2). The three identical ITS sequences, deposited in GenBank under Accession Nos. HM156495, HM156496, and HM156497, were identical to several ITS sequences of O. longipes, such as AF250777, EU327324, and EU327325. This has also supported that the disease was caused by this species. Herbarium specimens were deposited under the Accession Nos. HAL 2373F, HAL 2374F, and HAL 2375F at the Herbarium of Martin Luther University, Halle, Germany. To our knowledge, this is the first report of O. longipes in the UK. References: (1) A. Bolay. Cryptogam. Helv. 20:1, 2005. (2) T. Jankovics et al. Phytopathology 98:529, 2008. (3) L. Kiss et al. Plant Disease 92:818, 2008. (4) M. E. Noordeloos and W. M. Loerakker. Persoonia 14:51, 1989.

Temporal isolation explains host-related genetic differentiation in a group of widespread mycoparasitic fungi

Understanding the mechanisms responsible for divergence and specialization of pathogens on different hosts is of fundamental importance, especially in the context of the emergence of new diseases via host shifts. Temporal isolation has been reported in a few plants and parasites, but is probably one of the least studied speciation processes. We studied whether temporal isolation could be responsible for the maintenance of genetic differentiation among sympatric populations of Ampelomyces, widespread intracellular mycoparasites of powdery mildew fungi, themselves plant pathogens. The timing of transmission of Ampelomyces depends on the life cycles of the powdery mildew species they parasitize. Internal transcribed spacer sequences and microsatellite markers showed that Ampelomyces populations found in apple powdery mildew (Podosphaera leucotricha) were genetically highly differentiated from other Ampelomyces populations sampled from several other powdery mildew species across Europe, infecting plant hosts other than apple. While P. leucotricha starts its life cycle early in spring, and the main apple powdery mildew epidemics occur before summer, the fungal hosts of the other Ampelomyces cause epidemics mainly in summer and autumn. When two powdery mildew species were experimentally exposed to Ampelomyces strains naturally occurring in P. leucotricha in spring, and to strains naturally present in other mycohost species in autumn, cross-infections always occurred. Thus, the host-related genetic differentiation in Ampelomyces cannot be explained by narrow physiological specialization, because Ampelomyces were able to infect powdery mildew species they were unlikely to have encountered in nature, but instead appears to result from temporal isolation.

Recombinant human activated protein C attenuates cardiovascular and microcirculatory dysfunction in acute lung injury and septic shock

Introduction

This prospective, randomized, controlled, experimental animal study looks at the effects of recombinant human activated protein C (rhAPC) on global hemodynamics and microcirculation in ovine acute lung injury (ALI) and septic shock, resulting from smoke inhalation injury.

Methods

Twenty-one sheep (37 ± 2 kg) were operatively prepared for chronic study and randomly allocated to either the sham, control, or rhAPC group (n = 7 each). The control and rhAPC groups were subjected to insufflation of four sets of 12 breaths of cotton smoke followed by instillation of live Pseudomonas aeruginosa into both lung lobes, according to an established protocol. Healthy sham animals were not subjected to the injury and received only four sets of 12 breaths of room air and instillation of the vehicle (normal saline). rhAPC (24 μg/kg/hour) was intravenously administered from 1 hour post injury until the end of the 24-hour experiment. Regional microvascular blood flow was analyzed using colored microspheres. All sheep were mechanically ventilated with 100% oxygen, and fluid resuscitated with lactated Ringer's solution to maintain hematocrit at baseline levels.

Results

The rhAPC-associated reduction in heart malondialdehyde (MDA) and heart 3-nitrotyrosine (a reliable indicator of tissue injury) levels occurred parallel to a significant increase in mean arterial pressure and to a significant reduction in heart rate and cardiac output compared with untreated controls that showed a typical hypotensive, hyperdynamic response to the injury (P < 0.05). In addition, rhAPC significantly attenuated the changes in microvascular blood flow to the trachea, kidney, and spleen compared with untreated controls (P < 0.05 each). Blood flow to the ileum and pancreas, however, remained similar between groups. The cerebral blood flow as measured in cerebral cortex, cerebellum, thalamus, pons, and hypothalamus, was significantly increased in untreated controls, due to a loss of cerebral autoregulation in septic shock. rhAPC stabilized cerebral blood flow at baseline levels, as in the sham group.

Conclusions

We conclude that rhAPC stabilized cardiovascular functions and attenuated the changes in visceral and cerebral microcirculation in sheep suffering from ALI and septic shock by reduction of cardiac MDA and 3-nitrotyrosine.

First Report of Powdery Mildew on Lemon Balm (Melissa officinalis) Caused by Golovinomyces biocellatus in Hungary

Lemon balm is a well-known perennial, medicinal and culinary herb, and also a melliferous plant that is grown commercially in many parts of the world including Hungary. In October 2009, symptoms of powdery mildew infection were observed on lemon balm plants grown in several gardens in Budapest, Maklár, and Eger, Hungary, as well as in Ghenci, Romania. Abundant mycelium and conidial sporulation was observed on both leaf surfaces and stems. Conidia were produced in chains and were ellipsoid-ovoid to subcylindrical, measured 29 to 44 × 15 to 18 μm, and germinated with germ tubes produced apically or subapically on conidia. The basal septa of the conidiophores were sometimes displaced from the point of branching. The width of their foot cells increased from base to top and sometimes enlarged considerably at a particular point. Hyphal appressoria were nipple shaped. On the basis of these characteristics, the pathogen was identified as an Oidium sp. belonging to the subgenus Reticuloidium. The teleomorph stage was not found. To precisely identify the pathogen, DNA was extracted from mycelia collected from single leaves collected in Budapest and Ghenci with a Qiagen (Valencia, CA) DNeasy Plant Kit. The internal transcribed spacer (ITS) sequences of the nrDNA were amplified and sequenced as described in Jankovics et al. (3). The two ITS sequences, deposited in GenBank under Accession Nos. HM156493 and HM156494, were identical to several ITS sequences of Golovinomyces biocellatus, such as AB307675, AF011291, and EU035602. Thus, the pathogen was identified as G. biocellatus based on the host plant species, anamorph morphology, and ITS sequence. It was clearly distinguished from Neoerysiphe galeopsidis, another powdery mildew species known to infect lemon balm in Europe (1). Specimens were deposited under Accession Nos. HAL 2369F and HAL 2370F at the Herbarium of Martin Luther University, Halle, Germany. Pathogenicity tests were carried out in cabinets within a controlled environment as described for other powdery mildews in Jankovics et al. (3) using five potted healthy lemon balm plants bought from a nursery. The first powdery mildew colonies appeared 7 to 10 days after inoculation, and 2 to 3 weeks later, nearly all the leaves and stems of the three inoculated plants became covered with powdery mildew mycelium. Light microscopy confirmed that the pathogen was the anamorph of G. biocellatus. The two noninoculated plants remained healthy. This confirmed the pathogenicity of the fungus collected from the field to lemon balm. G. biocellatus has long been known to infect lemon balm in some European countries and elsewhere (1), but was not listed as a pathogen of this plant species in Hungary (4). However, it was reported from Romania, a neighboring country, more than 30 years ago (2). This suggests that G. biocellatus might have occurred in Hungary on lemon balm during the past decades without being reported in the literature. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) O. Constantinescu and G. Negrean. Sydowia 29:75, 1976-77. (3) T. Jankovics et al. Phytopathology 98:529, 2008. (4) Sz. Nagy and L. Kiss. Acta Phytopathol. Entomol. Hung. 41:79, 2006.

[Rectus sheath haematoma--rare complication of anticoagulant therapy]

The haematoma in the sheath of musculus rectus abdominis is a rare clinical entity. Its diagnosis is often difficult. Authors observed it in three patients who were on anticoagulant therapy. All subjects were female; two of them had decreased renal function. All three patients received thrombocyte aggregation inhibitor therapy as well. The anticoagulant treatment (low molecular weight heparin in two cases, warfarin in one case) caused excessive anticoagulant effect. The diagnosis, which could be suspected after the physical examination, was established in two cases by ultrasonography and in one case by computed tomography. Two patients were surgically treated while the third patient was healed with conservative treatment. To prevent the rectus sheath haematoma, authors suggest a particularly careful control of anticoagulant treatment in older females and in subjects with decreased renal function, especially if the patient takes thrombocyte aggregation inhibitors, too.

Muscle regeneration is undisturbed by repeated polytraumatic injury

INTRODUCTION

Clinical observations suggest that repeated injury within a week after a traumatic event impairs the regeneration of tissues. Our aim was to investigate the effect of repeated trauma on the proliferation of satellite cells in skeletal muscle tissue.

MATERIALS AND METHODS

Cold lesion injury was performed in the soleus muscle and in the motor cortex of anesthetized male Wistar rats 0, 1, or 2 times with 7 day intervals between the interventions. Following the last operation, 5-bromo-2'-deoxyuridine was injected i.p. for 6 or 12 days to label dividing cells. Gut epithelium was used as positive control. Immunohistochemistry was performed 1 and 5 weeks after the last injury and the sections were analyzed with confocal microscopy.

RESULTS

In the case of repeated trauma, the percentage of proliferating cells remained the same compared to single hit animals after 1 week (28.0 ± 2.5% and 29.6 ± 3.0%) as well as after 5 weeks (13.9 ± 1.8% and 14.5 ± 2.2%).

CONCLUSION

The second hit phenomenon is probably due to systemic factors rather than to a diminished regenerating potential of injured soft tissues.

Mesenchymal stem cells rescue cardiomyoblasts from cell death in an in vitro ischemia model via direct cell-to-cell connections

Background

Bone marrow derived mesenchymal stem cells (MSCs) are promising candidates for cell based therapies in myocardial infarction. However, the exact underlying cellular mechanisms are still not fully understood. Our aim was to explore the possible role of direct cell-to-cell interaction between ischemic H9c2 cardiomyoblasts and normal MSCs. Using an in vitro ischemia model of 150 minutes of oxygen glucose deprivation we investigated cell viability and cell interactions with confocal microscopy and flow cytometry.

Results

Our model revealed that adding normal MSCs to the ischemic cell population significantly decreased the ratio of dead H9c2 cells (H9c2 only: 0.85 ± 0.086 vs. H9c2+MSCs: 0.16 ± 0.035). This effect was dependent on direct cell-to-cell contact since co-cultivation with MSCs cultured in cell inserts did not exert the same beneficial effect (ratio of dead H9c2 cells: 0.90 ± 0.055). Confocal microscopy revealed that cardiomyoblasts and MSCs frequently formed 200-500 nm wide intercellular connections and cell fusion rarely occurred between these cells.

Conclusion

Based on these results we hypothesize that mesenchymal stem cells may reduce the number of dead cardiomyoblasts after ischemic damage via direct cell-to-cell interactions and intercellular tubular connections may play an important role in these processes.

Dual roles of reactive oxygen species and NADPH oxidase RBOHD in an Arabidopsis-Alternaria pathosystem

Arabidopsis (Arabidopsis thaliana) NADPH oxidases have been reported to suppress the spread of pathogen- and salicylic acid-induced cell death. Here, we present dual roles of RBOHD (for respiratory burst oxidase homolog D) in an Arabidopsis-Alternaria pathosystem, suggesting either initiation or prevention of cell death dependent on the distance from pathogen attack. Our data demonstrate that a rbohD knockout mutant exhibits increased spread of cell death at the macroscopic level upon inoculation with the fungus Alternaria brassicicola. However, the cellular patterns of reactive oxygen species accumulation and cell death are fundamentally different in the AtrbohD mutant compared with the wild type. Functional RBOHD causes marked extracellular hydrogen peroxide accumulation as well as cell death in distinct, single cells of A. brassicicola-infected wild-type plants. This single cell response is missing in the AtrbohD mutant, where infection triggers spreading-type necrosis preceded by less distinct chloroplastic hydrogen peroxide accumulation in large clusters of cells. While the salicylic acid analog benzothiadiazole induces the action of RBOHD and the development of cell death in infected tissues, the ethylene inhibitor aminoethoxyvinylglycine inhibits cell death, indicating that both salicylic acid and ethylene positively regulate RBOHD and cell death. Moreover, A. brassicicola-infected AtrbohD plants hyperaccumulate ethylene and free salicylic acid compared with the wild type, suggesting negative feedback regulation of salicylic acid and ethylene by RBOHD. We propose that functional RBOHD triggers death in cells that are damaged by fungal infection but simultaneously inhibits death in neighboring cells through the suppression of free salicylic acid and ethylene levels.

First European Report of a Leaf Spot on Common Ragweed (Ambrosia artemisiifolia) Caused by a Phoma sp

Common ragweed, native to North America, has recently become invasive in some parts of Europe. In Hungary, it has become the most widespread agricultural weed species and the most important producer of allergenic pollen since the 1990s. During surveys for its fungal plant pathogens to be evaluated as potential biological control agents (1), ragweed plants exhibiting necrotic spots on the leaves and stems were repeatedly found in Heves and Vas counties in Hungary in September 2004 and 2006. Numerous globose and ostiolate pycnidia, 68 to 115 μm in diameter, containing hyaline, unicellular conidia, 3 to 8 μm long, were found in necrotic tissues. On the basis of these characteristics, the fungus was identified as a Phoma sp., and 21 isolates were obtained on Czapek-Dox medium supplemented with 2% malt and 0.5% tetracycline in 2004 and 2006. Two well-sporulating isolates, designated Ph-5 and Ph-17, were selected for further studies. DNA was extracted from mycelium with a Qiagen DNeasy Plant Kit (Hilden, Germany) and the rDNA internal transcribed spacer (ITS) sequences were amplified and determined as described by Szentiványi et al. (2). The ITS sequences were identical in these two isolates and were 97 to 98% similar to those of Didymella bryoniae (anamorph Phoma cucurbitacearum), a pathogen of cucurbits, and also to those of other Phoma spp. No ITS sequences identical to those determined in Phoma isolates Ph-5 and Ph-17 were found in GenBank. Sequence data were deposited in GenBank (No. FJ794609). To test the pathogenicity of Ph-17 grown on Czapek-Dox medium with 2% malt, a 2 to 6 × 10⁵ conidia/ml aqueous suspension was used to inoculate 2-month-old potted ragweed plants and 1-month-old cucumber cv. Rajnai fürtös, bottle gourd (Lagenaria leucantha) cv. Minibottle, and watermelon (Citrullus lanatus) cv. Sugar Baby, which were all grown from seeds in a greenhouse. Plants were kept in transparent plastic chambers for 6 weeks. Five pots with one to three plants each were used for each plant species tested and the experiment was carried out twice. Noninoculated plants, two pots with one to three individuals for each species kept in the same way, served as controls. Necrotic spots with pycnidia developed on 38 to 47% of the leaves of all inoculated ragweed plants 18 to 25 days after inoculation, whereas all the cucurbitaceous plants tested, as well as the control ragweed plants, did not develop disease symptoms. Although the Phoma isolate Ph-17 was, based on ITS sequence data, closely related to D. bryoniae, it was not pathogenic to cucurbits. The pathogen was reisolated from two diseased ragweed plants. Several Phoma spp. strains were isolated from Ambrosia artemisiifolia in the United States and Canada (3,4), but to our knowledge, none were isolated outside North America. One of the strains has already been used as a potential biological control agent of ragweed in Canada, but then lost its virulence in culture (3). The biocontrol potential of the Hungarian Phoma sp. isolate Ph-17 against A. artemisiifolia is currently being investigated. To our knowledge, this is the first report of a Phoma sp. on A. artemisiifolia in Europe. References: (1) L. Kiss. Biocontrol Sci. Technol. 17:535, 2007. (2) O. Szentiványi et al. Mycol. Res. 109:429, 2005. (3) M. P. Teshler et al. Ambrosia artemisiifolia L., Common Ragweed (Asteraceae) in: Biological Control Programmes in Canada, 1981-2000. CABI, Wallingford, UK, 2002. (4) L. Zhou et al. Mycologia 97:612, 2005.

Rapid 'glycaemic swings' induce nitrosative stress, activate poly(ADP-ribose) polymerase and impair endothelial function in a rat model of diabetes mellitus

AIM/HYPOTHESIS

Postpandrial hyperglycaemia is a significant risk factor for the development of macrovascular diseases. There is no clear agreement in the field whether these alterations result from hyperglycaemic episodes or from exaggerated alterations ('glycaemic swings') in blood glucose. We compared the effect of stable high glucose with a model of poorly maintained insulin-controlled diabetes (on average lower glucose, but with large glycaemic swings) on the development of endothelial dysfunction in rats.

METHODS

Intermediate- or long-acting insulin was used to reduce mean blood glucose levels. One group of animals had stable low glucose levels, while animals in the other group exhibited rapid changes ('swings') in their blood glucose concentration. Acetylcholine-induced endothelium-dependent vascular relaxation of the thoracic aorta was measured. Immunohistochemistry, western blot analysis and flow cytometry were used to determine nitrotyrosine formation and poly(ADP-ribose) accumulation in the aorta, in circulating leucocytes and in bone marrow cells.

RESULTS

Steady normalisation of blood glucose levels (a model of well-controlled diabetes) protected against the development of endothelial dysfunction, poly(ADP-ribose) polymerase (PARP) activation and nitrotyrosine production. However, impairment of endothelium-dependent relaxation was found in the animals undergoing glycaemic swings, even though the fructosamine levels in these animals were lower than in the untreated diabetic rats. This was associated with elevated PARP activation in the aorta and in bone marrow cells that was similar to or even more pronounced than that seen in the untreated diabetic animals.

CONCLUSIONS/INTERPRETATION

Large glycaemic swings exert deleterious cardiovascular effects in diabetes mellitus, in part via enhanced activation of the PARP pathway.

First Report of Powdery Mildew (Oidium sp.) on Pincushion Flower (Scabiosa columbaria) in New York

Scabiosa columbaria (Dipsacaceae) is a popular perennial ornamental in the United States. It is native to Europe and was introduced to North America by nursery trade only recently. In the spring of 2006, symptoms of powdery mildew infection were observed on overwintered plants of S. columbaria cv. Butterfly Blue in a nursery in Cutchogue, NY. White powdery mildew mycelia with abundant sporulation were observed on upper and lower leaf surfaces. The portions of leaves with powdery mildew colonies often showed purplish discoloration. Conidia were cylindric to doliiform, measured 20 to 33 × 10 to 15 μm, and were produced singly on 60 to 130 μm long conidiophores consisting of a foot-cell measuring 20 to 50 × 6 to 10 μm, followed by one to three, 12 to 40 μm long cells. Hyphal appressoria were lobed or multilobed. The teleomorph stage was not found. On the basis of these characteristics, the pathogen was identified as an Oidium sp. belonging to the subgenus Pseudoidium. Recently, an anamorphic powdery mildew fungus with similar morphological characteristics, identified as Erysiphe knautiae, was reported on S. columbaria cv. Butterfly Blue in Washington (2). E. knautiae is a common powdery mildew species of dipsacaceous plants such as Scabiosa spp. and Knautia spp. in Europe and Asia (1). To determine whether the fungus reported here was E. knautiae, DNA was extracted from its mycelium, and the internal transcribed spacer (ITS) region of the ribosomal DNA was amplified and sequenced as described earlier (4). No ITS sequences are available in public DNA databases for E. knautiae, thus, we determined this sequence in a specimen of E. knautiae collected from Knautia arvensis in The Netherlands. Herbarium specimens of the Oidium sp. infecting S. columbaria in New York and E. knautiae from the Netherlands were deposited at the U.S. National Fungus Collections under accession numbers BPI 878259 and BPI 878258, respectively. The ITS sequence from Oidium sp. infecting S. columbaria in New York (GenBank Accession No. EU377474) differed in two nucleotides from that of E. knautiae infecting K. arvensis in the Netherlands (GenBank Accession No. EU377475). These two ITS sequences were also more than 99% similar to those of some newly emerged anamorphic powdery mildew fungi: Oidium neolycopersici and other Oidium spp. infecting Chelidonium majus, Passiflora caerulea, and some crassulaceous plants (3,4). Thus, it is unclear whether the fungus reported here was E. knautiae known from Eurasia or an Oidium sp. that has acquired pathogenicity to S. columbaria. To our knowledge, this is the first report of powdery mildew on S. columbaria in New York. References: (1) U. Braun. Beih. Nova Hedwigia 89:1, 1987. (2) D. A. Glawe and G. G. Grove. Online publication. doi:10.1094/PHP-2005-1024-01-BR. Plant Health Progress, 2005. (3) B. Henricot. Plant Pathol. 57:779, 2008. (4) T. Jankovics et al. Phytopathology 98:529, 2008.

Alpha7 cholinergic-agonist prevents systemic inflammation and improves survival during resuscitation

Severe haemorrhage is a common cause of death despite the recent advances in critical care. Conventional resuscitation fluids are designed to re-establish tissue perfusion, but they fail to prevent inflammatory responses during resuscitation. Our previous studies indicated that the vagus nerve can modulate systemic inflammation via the alpha7 nicotinic acetylcholine receptor (alpha7nAchR). Here, we report that the alpha7nAChR-agonist, GTS, restrains systemic inflammation and improves survival during resuscitation. Resuscitation with GTS rescued all the animals from lethal haemorrhage in a concentration-dependent manner. Unlike conventional resuscitation fluids, GTS inhibited the production of characteristic inflammatory and cardiodepressant factors including tumour necrosis factor (TNF) and high mobility group B protein-1 (HMGB1). Resuscitation with GTS was particularly effective in restraining systemic TNF responses and inhibiting its production in the spleen. At the molecular level, GTS inhibited p65RelA but not RelB NF-kappaB during resuscitation. Unlike non-specific nicotinic agonists, GTS inhibited serum protein TNF levels in both normal and splenectomized, haemorrhagic animals. Resuscitation with GTS inhibited poly(ADP-ribose) polymerase and systemic HMGB1 levels. Our studies suggest that GTS provides significant advantages as compared with non-specific nicotinic agonists, and it could be a promising anti-inflammatory supplement to improve survival during resuscitation.

Oidium longipes, A New Powdery Mildew Fungus on Petunia in the USA: A Potential Threat to Ornamental and Vegetable Solanaceous Crops

This is the first North American report of Oidium longipes, an anamorphic powdery mildew species described recently in Europe. It was found on vegetatively propagated petunia grown in a commercial greenhouse in New Jersey, USA, where it caused a rapidly spreading disease. The pathogen might have originated offshore and may have already been distributed in the United States through horticultural trade. During field surveys in Europe, it was found on petunia in Hungary and Austria as well; this is the first report of O. longipes from these two countries. A detailed light microscopy study of American and European specimens of O. longipes, including freshly collected samples and authentic herbarium specimens, revealed that its conidiophore morphology is more variable than illustrated in the original species description or in subsequent works. Microcycle conidiation, a process not yet known to occur in powdery mildews, was repeatedly observed in O. longipes. The rDNA internal transcribed spacer (ITS) sequences were identical in colonies containing different conidiophore types as well as in a total of five specimens collected from petunia in the United States, Austria, Hungary, Germany, and Switzerland. A phylogenetic analysis of the ITS sequences revealed that the closest known relative of O. longipes is O. lycopersici, known to infect tomato only in Australia. Cross-inoculation tests showed that O. longipes from petunia heavily infected tobacco cv. Xanthi, while the tomato and eggplant cultivars tested were moderately susceptible to this pathogen. These results indicate that its spread represents a potential danger to a number of solanaceous crops. Our ad hoc field surveys conducted in 2006 and 2007 did not detect it outside New Jersey in the United States; all the other powdery mildew-infected petunias, collected in New York and Indiana, were infected by Podosphaera xanthii. In Europe, most of the powdery mildew-infected petunias examined in this study were infected by P. xanthii or Golovinomyces orontii. Our multiple inoculation tests revealed that the same petunia plants and even the same leaves can be infected concomitantly by O. longipes, O. neolycopersici, G. orontii, and P. xanthii. Thus, it is at present unclear to what extent O. longipes contributes to the powdery mildew epidemics that develop year after year on solanaceous plants in many parts of the world.

Oidium neolycopersici: intraspecific variability inferred from amplified fragment length polymorphism analysis and relationship with closely related powdery mildew fungi infecting various plant species

Previous works indicated a considerable variation in the pathogenicity, virulence, and host range of Oidium neolycopersici isolates causing tomato powdery mildew epidemics in many parts of the world. In this study, rDNA internal transcribed spacer (ITS) sequences, and amplified fragment length polymorphism (AFLP) patterns were analyzed in 17 O. neolycopersici samples collected in Europe, North America, and Japan, including those which overcame some of the tomato major resistance genes. The ITS sequences were identical in all 10 samples tested and were also identical to ITS sequences of eight previously studied O. neolycopersici specimens. The AFLP analysis revealed a high genetic diversity in O. neolycopersici and indicated that all 17 samples represented different genotypes. This might suggest the existence of either a yet unrevealed sexual reproduction or other genetic mechanisms that maintain a high genetic variability in O. neolycopersici. No clear correlation was found between the virulence and the AFLP patterns of the O. neolycopersici isolates studied. The relationship between O. neolycopersici and powdery mildew anamorphs infecting Aquilegia vulgaris, Chelidonium majus, Passiflora caerulea, and Sedum alboroseum was also investigated. These anamorphs are morphologically indistinguishable from and phylogenetically closely related to O. neolycopersici. The cross-inoculation tests and the analyses of ITS sequences and AFLP patterns jointly indicated that the powdery mildew anamorphs collected from the above mentioned plant species all represent distinct, but closely related species according to the phylogenetic species recognition. All these species were pathogenic only to their original host plant species, except O. neolycopersici which infected S. alboroseum, tobacco, petunia, and Arabidopsis thaliana, in addition to tomato, in cross-inoculation tests. This is the first genome-wide study that investigates the relationships among powdery mildews that are closely related based on ITS sequences and morphology. The results indicate that morphologically indistinguishable powdery mildews that differed in only one to five single nucleotide positions in their ITS region are to be considered as different taxa with distinct host ranges.

First Report of Powdery Mildew on Pyrus calleryana Caused by Podosphaera leucotricha

Callery pear (Pyrus calleryana Decne.) is native to Asia and its varieties are planted as ornamentals in urban areas worldwide. It is also used as a source of resistance to fireblight in some breeding programs. In April 2007, symptoms of powdery mildew infection were observed on the foliage of almost every P. calleryana cv. Chanticleer tree planted along a 1.5-km road in Budapest, Hungary. These trees were planted 5 to 6 years ago and were the first callery pears used as ornamentals in Hungary. Powdery mildew infections were also detected on P. calleryana trees planted in other parts of the city. White powdery mildew mycelium appeared on the lower and sometimes upper leaf surfaces, especially on young shoots, and caused chlorotic spots on the upper leaf surfaces and severe distortions of leaves. The spread of the infection was monitored between April and August of 2007 in several sample sites. More than 100 trees that were examined became heavily infected by May 2007. Powdery mildew conidiophores were typical of the genus Oidium subgen. Fibroidium, the anamorph of the teleomorph genus Podosphaera (2). Conidia developed in chains, contained fibrosin bodies, germinated at one of their ends with germ tubes terminating in unlobed appressoria, and measured 16 to 27 × 10 to 15 μm. Hyphal appressoria were nipple shaped or inconspicuous. The teleomorph was not found. To precisely identify the pathogen, DNA was extracted from conidia collected with a sterile brush from a single leaf using a Qiagen DNeasy Plant Kit (Hilden, Germany), and the internal transcribed spacer (ITS) sequence of the ribosomal DNA was amplified and determined as described by Szentiványi et al. (3). The ITS sequence, deposited in GenBank under Accession No. EU148597, was identical to those determined in Podosphaera leucotricha (Ell. & Ev.) Salmon collected from apple in Australia (GenBank Accession No. AF073353) and Canada (GenBank Accession No. AY157844) and also from pear in Canada (GenBank Accession No. AY157845). Thus, the pathogen was identified as Podosphaera leucotricha on the basis of the host genus, morphology of the anamorph, and ITS sequence. Specimens were deposited under Accession No. BPI878262 at the U.S. National Fungus Collection. To our knowledge, Podosphaera leucotricha has not been reported on P. calleryana in any parts of the world so far. An Oidium sp. infecting this plant in Australia was listed by Amano (1), but the exact identity of that fungus is not known. Thus, this is the first report of an identified powdery mildew fungus on P. calleryana. References: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi. Japan Scientific Societies Press, Tokyo, 1986. (2) U. Braun et al. Pages 13-55 in: The Powdery Mildews: A Comprehensive Treatise. R. R Bélanger et al., eds. American Phytopathological Society, St Paul, MN, 2002. (3) O. Szentiványi et al. Mycol. Res. 109:429, 2005.

Treatment with insulin inhibits poly(ADP-ribose)polymerase activation in a rat model of endotoxemia

In critically ill patients various conditions may lead to the activation of poly(ADP-ribose) polymerase (PARP). By promoting cellular energetic dysfunction, and by enhancing pro-inflammatory gene expression, PARP activation significantly contributes to the pathogenesis of shock. PARP activation is usually triggered by DNA strand breakage, which is typically the result of the overproduction of various reactive oxidant species. One of the pathophysiological conditions associated with PARP activation is hyperglycemia, where the reactive species are produced from the mitochondria and other cellular sources. In the present study we tested whether endotoxin-induced PARP activation and pro-inflammatory mediator production can be modified by insulin therapy. Rats subjected to bacterial lipopolysaccharide (LPS) with or without insulin co-treatment were studied. LPS-induced PARP activation in circulating lymphocytes was measured by flow cytometry, tumor necrosis factor alpha (TNF-alpha) production was measured by ELISA. The direct effect of insulin on the PARP activity of mononuclear leukocytes and human umbilical vein endothelial cells (HUVEC) in elevated glucose conditions was tested in vitro. LPS-induced significant hyperglycemic response activated PARP in circulating lymphocytes and induced TNF-alpha production. Insulin treatment prevented LPS-induced hyperglycemic response, blocked PARP activation and blunted LPS-induced TNF-alpha response. Insulin treatment caused a slight reduction in the PARP activity of mononuclear cells and HUVECs in vitro. We demonstrate that insulin treatment blocks LPS-induced PARP activation in vivo. We propose that this effect is mainly indirect, and occurs due to the prevention of stress induced hyperglycemia, with a direct cellular effect of insulin playing a potential minor supplemental role. The current findings may have significant implications in the context of the emerging concept of tight glycemic control and insulin treatment for critically ill patients.

Hydrogen sulfide attenuates myocardial ischemia-reperfusion injury by preservation of mitochondrial function

The recent discovery that hydrogen sulfide (H(2)S) is an endogenously produced gaseous second messenger capable of modulating many physiological processes, much like nitric oxide, prompted us to investigate the potential of H(2)S as a cardioprotective agent. In the current study, we demonstrate that the delivery of H(2)S at the time of reperfusion limits infarct size and preserves left ventricular (LV) function in an in vivo model of myocardial ischemia-reperfusion (MI-R). This observed cytoprotection is associated with an inhibition of myocardial inflammation and a preservation of both mitochondrial structure and function after I-R injury. Additionally, we show that modulation of endogenously produced H(2)S by cardiac-specific overexpression of cystathionine gamma-lyase (alpha-MHC-CGL-Tg mouse) significantly limits the extent of injury. These findings demonstrate that H(2)S may be of value in cytoprotection during the evolution of myocardial infarction and that either administration of H(2)S or the modulation of endogenous production may be of clinical benefit in ischemic disorders.

S-nitrosoglutathione-containing hydrogel increases dermal blood flow in streptozotocin-induced diabetic rats

BACKGROUND

Endothelial dysfunction is characterized by decreased vasodilatory capacity of the arterioles mainly due to the reduced release of nitric oxide (NO). Application of NO donors may prevent or even reverse the consequences of endothelial dysfunction, such as diabetic leg ulcers.

OBJECTIVES

To investigate the vasodilatory capacity and the possible side-effects of topical application of an NO donor-containing hydrogel in diabetic rats.

METHODS

S-nitrosoglutathione (GSNO) was incorporated in Pluronic F127 hydrogel and applied on the foot sole skin of healthy and streptozotocin-induced diabetic rats. Blood flow was monitored using a laser-Doppler probe. Nitrotyrosine formation, a possible side-effect of GSNO action, was evaluated by Western blotting of skin protein extracts. Systemic circulatory side-effects were investigated by monitoring blood pressure and heart rate during the application.

RESULTS

The hydrogel alone did not induce any changes in microvascular flow, while GSNO-containing hydrogel caused a twofold increase in perfusion. This effect was similar in diabetic and healthy animals. Topical GSNO application did not increase the nitrotyrosine content of skin proteins, nor did it have any effect on blood pressure or heart rate.

CONCLUSIONS

Dermal application of GSNO may be an effective treatment for promoting the local vasodilation in both healthy and diabetic states, without inducing protein nitration or alterations in blood pressure or heart rate.

Human heart mitochondria do not produce physiologically relevant quantities of nitric oxide

Previous studies raised the possibility that nitric oxide synthase is present in heart mitochondria (mtNOS) and the existence of such an enzyme became generally accepted. However, original experimental evidence is rather scarce and positive identification of the enzyme is lacking. We aimed to detect an NOS protein in human and mouse heart mitochondria and to measure the level of NO released from the organelles. Western blotting with 7 different anti-NOS antibodies failed to detect a NOS-like protein in mitochondria. Immunoprecipitation or substrate-affinity purification of the samples concentrated NOS in control preparations but not in mitochondria. Release of NO from live respiring human mitochondria was below 2 ppb after 45 min of incubation. In a bioassay system, mitochondrial suspension failed to cause vasodilation of human mammary artery segments. These results indicate that mitochondria do not produce physiologically relevant quantities of NO in the heart and are unlikely to have any physiological importance as NO donors, nor do they contain a recognizable mtNOS enzyme.

[Isolated injury of the gallbladder. A rare cause of hemorrhagic shock after blunt abdominal trauma in a patient with liver cirrhosis]

Isolated injuries to the gallbladder are extremely rare in blunt abdominal trauma, with a reported incidence of less than 2%. We report a case with partial avulsion of the gallbladder and subsequent hemorrhagic shock in a patient with liver cirrhosis. Although the gallbladder injury was demonstrated on CT images (with contrast enhancement in the bed of the gallbladder), the correct diagnosis was not established preoperatively. Emergency laparotomy revealed partial avulsion of the gallbladder and the underlying condition of severe liver cirrhosis with ascites. We estimate that the gallbladder avulsion occurred due to compressional waves of the ascites (during blunt abdominal injury) which may have sheared off the gallbladder from the cirrhotic liver. The patient received cholecystectomy, which is recommended as standard in case of gallbladder injury.

Effects of 7-ketocholesterol on the activity of endothelial poly(ADP-ribose) polymerase and on endothelium-dependent relaxant function

Oxidative and nitrosative stress play an important role in the development of endothelial vascular dysfunction during early atherosclerosis. Oxidative stress activates the nuclear enzyme poly(ADP-ribose) polymerase (PARP) in endothelial cells. In patients with atherosclerosis the level of oxidized LDL in the plasma is elevated. In oxidized LDL various oxysterols have been identified, such as 7-ketocholesterol (7K). 7K has been shown to induce PARP activation in microglial cells. The aim of the current study was to clarify the effects of 7K on the activity of endothelial PARP and on the endothelium-dependent relaxant function of blood vessels. We treated human umbilical vein endothelial (HUVEC) cells with 2-16 microg/ml 7K as well as vascular rings harvested from BALB/c mouse thoracic aorta with 90 microg/ml 7K for 2 h. A group of mice was treated with 7K subcutaneously for 1 week (10 mg/kg/day). We also conducted in vitro and in vivo experiments using pretreatment with buthionine sulphoximine (BSO), a glutathione-lowering agent. The activity of PARP was calculated by measurement of tritiated NAD incorporation. The activity of PARP increased significantly in 7K-treated HUVEC cells. After BSO pretreatment, this increase was higher. Isolated vascular rings demonstrated no change in endothelium-dependent relaxant function after 2 h of incubation with 7K, even after BSO pretreatment. In vivo treatment with 7K for 1 week had no effect on the relaxant function. Our experimental results suggest that although 7-ketocholesterol can activate PARP enzyme in endothelial cells, it is not sufficient on its own to cause impairment in the endothelium-dependent vascular reactivity.

A morphologically ill-founded powdery mildew species, Pleochaeta indica, is recognized as a phylogenetic species based on the analysis of the nuclear ribosomal DNA sequences

Morphological characteristics of a powdery mildew fungus found on Celtis australis in the Indian Himalayas coincided with those of Pleochaeta indica, described from this tree species in India, as well with those of P. shiraiana, known to infect C. australis and other plant species in Asia. This suggested that the original description of P. indica based on morphological patterns was not well founded and this taxon could be reduced to synonymy with P. shiraiana. However, phylogenetic analyses of the rDNA 28S and ITS sequences determined in some Indian Pleochaeta specimens from C. australis showed that this fungus is closely related, but not identical to P. shiraiana infecting C. sinensis in Japan which served as the basis of the original description of P. shiraiana. Molecular clock analysis of the ITS region and that of the 28S rDNA indicated that the split between the Japanese P. shiraiana infecting C. sinensis and Pleochaeta sp. infecting C. australis in India may have occurred 2.0-8.5 million years ago in the Pliocene and may have coincided with the formation of the Himalayan mountains and the global cooling of the Earth during the late Tertiary. Thus, P. indica is recognized in this study as a distinct phylogenetic species, although our morphological study showed that its description as a morphological species was not well founded. This is a striking example of a cryptic species which is genetically different from close relatives but cannot be distinguished from them based on morphology.

Mitochondrial NO and reactive nitrogen species production: Does mtNOS exist?

It is more than 10 years now that mitochondria are suspected to be sources of nitric oxide (NO). This hypothesis is intriguing since NO has multiple targets within the organelle and it is even suggested that mitochondria are the primary targets of NO in the cell. Most remarkably, nanomolar concentrations of NO can inhibit mitochondrial respiration, so even a small amount of NO in the mitochondrial matrix may regulate ATP synthesis. Therefore, the idea that mitochondria themselves are capable of NO production is an important concept in several physiological and pathological mechanisms. However, this field of research generates surprisingly few original papers and the published studies contain conflicting results. The reliability of the results is frequently questioned since they are seldom reproduced by independent investigators. Until 2003, all papers published in this field showed affirmative results but since then several studies directly challenged the existence of a mitochondrial nitric oxide synthase. The present review aims to summarize the most recent developments in mitochondrial NO production, highlights a few unsolved questions, and proposes new directions for future work in this research area.

Ampelomyces mycoparasites from apple powdery mildew identified as a distinct group based on single-stranded conformation polymorphism analysis of the rDNA ITS region

Pycnidial fungi belonging to the genus Ampelomyces are the most common natural antagonists of powdery mildews worldwide. During a study of the interactions between apple powdery mildew (Podosphaera leucotricha) and Ampelomyces mycoparasites, 52 new Ampelomyces isolates were obtained from P. leucotricha and, in addition, 13 new isolates from other species of the Erysiphaceae in four European countries. Their genetic diversity was screened using single-stranded conformation polymorphism (SSCP) analysis of the internal transcribed spacer (ITS) region of the ribosomal DNA (rDNA). For comparison, 24 isolates obtained from genetic resource collections or other sources were included in this study. Based on the ITS-SSCP patterns, the isolates were placed in eight groups. The isolates belonged to two types based on their growth in culture. The faster-growing and the slower-growing isolates were included in different SSCP groups. A phylogenetic analysis of the ITS sequences of representatives of these groups confirmed the results obtained with the SSCP method, and showed that the faster-growing isolates do not belong to Ampelomyces as suggested by earlier studies. All the isolates from P. leucotricha fell into a distinct SSCP group of genetically homogeneous isolates. This suggests that Ampelomyces mycoparasites which occur in apple powdery mildew are slightly different from the other Ampelomyces groups which contain mycoparasites from various powdery mildew species. This may be because the main growth period of Ampelomyces mycoparasites in apple powdery mildew is isolated in time from that of Ampelomyces isolates that occur in other species of the Erysiphaceae. P. leucotricha starts its life-cycle early in the season, usually in March-April, while most powdery mildews are active in the same environments only late in the year.

Molecular phylogeny and evolution of the maple powdery mildew (Sawadaea, Erysiphaceae) inferred from nuclear rDNA sequences

To understand the phylogenetic relationships and evolution of the powdery mildew genus Sawadaea (Ascomycota: Erysiphaceae), obligate parasitic fungi of maples, we performed molecular phylogenetic analyses based on 47 ITS and ten 28S rDNA sequences. Seven major clades of Sawadaea, each represented by powdery mildew specimens collected from a single or a small number of closely related sections of Acer (maples), were identified in this study, suggesting that a close evolutionary relationship exists between Acer (host) and Sawadaea (parasite). A 6-11-base insertion/deletion was found in the ITS1 region of Sawadaea, and the presence or absence of the indel was consistent within the respective clades. Because the outgroup genera Podosphaera and Cystotheca have no deletions in these sites, deletion of the sequences may have occurred during the divergence of the respective clades of Sawadaea. The seven clades of Sawadaea were divided into two geographical groups, viz. an East Asian and a global group, based on the countries of collection. Calculation of the evolutionary timing of Sawadaea using molecular clocks showed that the divergence of different species of Acer occurred many millions of years before the radiation of Sawadaea. Thus, the close evolutionary relationship between Sawadaea and Acer found in this study might not be due to a true coevolutionary process. Powdery mildew fungi belonging to Sawadaea may have jumped onto Acer spp. long after the radiation of the major sections of these trees, and then expanded their host ranges according to the phylogeny and geographical distribution of Acer.