Distribution and function of epistomatal mucilage plugs

Investigation of 67 gymnosperm and angiosperm species belonging to 25 orders shows that epistomatal mucilage plugs are a widespread phenomenon. Measurements of the leaf water status by using the leaf patch clamp pressure technique suggest that the mucilage plugs are involved in moisture uptake and buffering leaf cells against complete turgor pressure loss at low humidity.

Pharmacotherapy guidelines for the aged by family doctors for the use of family doctors

Part C of the guideline is preceded by Part B General Pharmacology IJCPT. 2008; 46: 600 - 617. Included in Part C are practical guidelines for improving the therapy of some age-specific diseases and problems commonly encountered in general practice. The article in this issue is dedicated to the therapy of Dementia and M. Parkinson. Further guidelines for the other age specific diseases and problems named above will be published in the following issues of IJCPT. An important feature of these guidelines are the inclusion of Levels of Evidence and of the Strength of Recommendations for the therapy which are shown when reliable studies are available. (For both see levels of evidence at the end of this article.).

Altered expression of tumor protein D52 regulates apoptosis and migration of prostate cancer cells

Tumor protein D52 (TPD52) is a protein found to be overexpressed in prostate and breast cancer due to gene amplification. However, its physiological function remains under investigation. In the present study, we investigated the response of the LNCaP human prostate carcinoma cell line to deregulation of TPD52 expression. Proteomic analysis of prostate biopsies showed TPD52 overexpression at the protein level, whereas its transcriptional upregulation was demonstrated by real-time PCR. Transfection of LNCaP cells with a specific small hairpin RNA giving efficient knockdown of TPD52 resulted in significant cell death of the carcinoma LNCaP cells. As demonstrated by activation of caspases (caspase-3 and -9), and by the loss of mitochondrial membrane potential, cell death occurs due to apoptosis. The disruption of the mitochondrial membrane potential indicates that TPD52 acts upstream of the mitochondrial apoptotic reaction. To study the effect of TPD52 expression on cell proliferation, LNCaP cells were either transfected with enhanced green fluorescence protein-TPD52 or a specific small hairpin RNA. Enhanced green fluorescence protein-TPD52 overexpressing cells showed an increased proliferation rate, whereas TPD52-depleted cells showed the reverse effect. Additionally, we demonstrate that exogenous expression of TPD52 promotes cell migration via alphav beta3 integrin in prostate cancer cells through activation of the protein kinase B/Akt signaling pathway. From these results, we conclude that TPD52 plays an important role in various molecular events, particularly in the morphological diversification and dissemination of prostate carcinoma cells, and may be a promising target with respect to developing new therapeutic strategies to treat prostate cancer.

The mechanisms of refilling of xylem conduits and bleeding of tall birch during spring

Seasonal variations in osmolality and components of xylem sap in tall birch trees were determined using several techniques. Xylem sap was extracted from branch and trunk sections of 58 trees using the very rapid gas bubble-based jet-discharge method. The 5-cm long wood pieces were taken at short intervals over the entire tree height. The data show that large biphasic osmolality gradients temporarily exist within the conducting xylem conduits during leaf emergence (up to 272 mosmol x kg(-1) at the apex). These gradients (arising mainly from glucose and fructose) were clearly held within the xylem conduit as demonstrated by (1)H NMR imaging of intact twigs. Refilling experiments with benzene, sucrose infusion, electron and light microscopy, as well as (1)H NMR chemical shift microimaging provided evidence that the xylem of birch represents a compartment confined by solute-reflecting barriers (radial: lipid linings/lipid bodies; axial: presumably air-filled spaces). These features allow transformation of osmolality gradients into osmotic pressure gradients. Refilling of the xylem occurs by a dual mechanism: from the base (by root pressure) and from the top (by hydrostatic pressure generated by xylem-bound osmotic pressure). The generation of osmotic pressure gradients was accompanied by bleeding. Bleeding could be observed at a height of up to 21 m. Bleeding rates measured at a given height decreased exponentially with time. Evidence is presented that the driving force for bleeding is the weight of the static water columns above the bleeding point. The pressure exerted by the water columns and the bleeding volume depend on the water-filling status of (communicating) vessels.

The interleukin-10 promoter haplotype ATA is a putative risk factor for aggressive periodontitis

BACKGROUND AND OBJECTIVE

Interleukin-10 has been described as an anti-inflammatory cytokine and a B-cell proliferation factor. Promoter polymorphisms of the interleukin-10 gene have been associated with altered interleukin-10 expression. Therefore, the aim of this study was to evaluate three polymorphisms at positions -1082G>A, -819C>T and -590C>A in patients with generalized chronic periodontitis (n = 27) and generalized aggressive periodontitis (n = 32) in comparison with periodontitis-free controls (n = 34).

MATERIAL AND METHODS

Interleukin-10 promoter polymorphisms were analyzed by polymerase chain reaction with sequence-specific primers (PCR-SSP). Distributions of single alleles, genotypes and haplotypes were calculated by the chi-square test. Risk factor analyses were carried out by logistic regression. Subgingival bacteria were subjected to molecular biological analyses using the micro-Ident test.

RESULTS

The combination ATA/ATA was found only in patients with aggressive periodontitis (15.6 vs. 0.0%, p = 0.023). Taking into account age, gender, smoking and plaque level, an increased odds ratio (3.7, p = 0.04) for aggressive periodontitis was shown for subjects with the haplotype ATA. Prevotella intermedia was found to be decreased in ACC- positive (41.3 vs. 66.7%, p = 0.022), ATA-positive (33.3 vs. 57.1%, p = 0.032) and ACC/ATA-positive (20.0 vs. 55.9%, p = 0.002) individuals. In GCC/GCC-positive subjects, P. intermedia occurred more frequently (86.7 vs. 42.3%, p = 0.002).

CONCLUSION

The haplotype ATA, which is known as a 'low interleukin-10 producer' is a putative risk indicator for generalized aggressive periodontitis.

Foliar water supply of tall trees: evidence for mucilage-facilitated moisture uptake from the atmosphere and the impact on pressure bomb measurements

The water supply to leaves of 25 to 60 m tall trees (including high-salinity-tolerant ones) was studied. The filling status of the xylem vessels was determined by xylem sap extraction (using jet-discharge, gravity-discharge, and centrifugation) and by (1)H nuclear magnetic resonance imaging of wood pieces. Simultaneously, pressure bomb experiments were performed along the entire trunk of the trees up to a height of 57 m. Clear-cut evidence was found that the balancing pressure (P(b)) values of leafy twigs were dictated by the ambient relative humidity rather than by height. Refilling of xylem vessels of apical leaves (branches) obviously mainly occurred via moisture uptake from the atmosphere. These findings could be traced back to the hydration and rehydration of mucilage layers on the leaf surfaces and/or of epistomatal mucilage plugs. Xylem vessels also contained mucilage. Mucilage formation was apparently enforced by water stress. The observed mucilage-based foliar water uptake and humidity dependency of the P(b) values are at variance with the cohesion-tension theory and with the hypothesis that P(b) measurements yield information about the relationships between xylem pressure gradients and height.

A novel, non-invasive, online-monitoring, versatile and easy plant-based probe for measuring leaf water status

A high-precision pressure probe is described which allows non-invasive online-monitoring of the water relations of intact leaves. Real-time recording of the leaf water status occurred by data transfer to an Internet server. The leaf patch clamp pressure probe measures the attenuated pressure, P(p), of a leaf patch in response to a constant clamp pressure, P(clamp). P(p) is sensed by a miniaturized silicone pressure sensor integrated into the device. The magnitude of P(p) is dictated by the transfer function of the leaf, T(f), which is a function of leaf patch volume and ultimately of cell turgor pressure, P(c), as shown theoretically. The power function T(f)=f(P(c)) theoretically derived was experimentally confirmed by concomitant P(p) and P(c) measurements on intact leaflets of the liana Tetrastigma voinierianum under greenhouse conditions. Simultaneous P(p) recordings on leaflets up to 10 m height above ground demonstrated that changes in T(f) induced by P(c) changes due to changes of microclimate and/or of the irrigation regime were sensitively reflected in corresponding changes of P(p). Analysis of the data show that transpirational water loss during the morning hours was associated with a transient rise in turgor pressure gradients within the leaflets. Subsequent recovery of turgescence during the afternoon was much faster than the preceding transpiration-induced water loss if the plants were well irrigated. Our data show the enormous potential of the leaf patch clamp pressure probe for leaf water studies including unravelling of the hydraulic communication between neighbouring leaves and over long distances within tall plants (trees).

Vanadium pentoxide-coated ultrafine titanium dioxide particles induce cellular damage and micronucleus formation in V79 cells

Surface-treated titanium dioxide (TiO(2)) particles coated with vanadium pentoxide (V(2)O(5)) are used industrially for selective catalytic reactions such as the removal of nitrous oxide from exhaust gases of combustion power plants (SCR process) and in biomaterials for increasing the strength of implants. In the present study, untreated ultrafine TiO(2) particles (anatase, diameter: 30-50 nm) and vanadium pentoxide (V(2)O(5))-treated anatase particles were tested for their cyto- and genotoxic effects in V79 cells (hamster lung fibroblasts). Cytotoxic effects of the particles were assessed by trypan blue exclusion, while genotoxic effects were investigated by micronucleus (MN) assay. In addition, the generation of reactive oxygen species (ROS) was determined by the acellular method of electron spin resonance technique (ESR) and by the cellular technique of determination of thiobarbituric acid-reactive substances (TBARS). Our results demonstrate that V(2)O(5)-treated TiO(2) particles induce more potent cyto- and genotoxic effects than untreated particles. Further, acellular and cellular radical formation was more pronounced with V(2)O(5)-anatase than untreated anatase. Thus, data indicate that V(2)O(5)-treated TiO(2) particles were more reactive than natural anatase and capable of inducing DNA damage in mammalian cells through production of free radicals.

[MRI screening before stem cell transplantation--necessary?]

PURPOSE

In the context of stem cell transplantation (SCT), we often observe neurological complications as a consequence of immune system suppression, conditioning therapy or prophylaxis and treatment of graft-versus-host disease. Furthermore, cerebral lesions in existence prior to transplantation can be found. The aim of this study was to evaluate the benefit of cerebral magnetic resonance imaging (MRI) prior to stem cell transplantation.

PATIENTS AND METHOD

Cerebral MR examinations of 116 children and adolescents were performed before SCT. Patients ranged in age from 1.1 to 21.4 years (mean 12.6 years). All MR images were obtained by a 1.5 T system. The predefined short protocol included an axial T 1-weighted SE sequence and a coronary T 2-weighted TSE sequence. We evaluated existing cerebral lesions, the diameter of the ventricular system, and the paranasal sinuses. In the case of pathological findings, the short examination protocol was expanded.

RESULTS

In 5 of 116 children (4.3 %) we observed prior to SCT findings requiring immediate treatment although the patients did not show any clinical symptoms (1 x aspergilloma, 1 x hemorrhage of vascular anomaly). An increased risk of bleeding caused by cavernoma or another vascular anomaly without hemorrhage also had to be taken into account. 32 of 116 patients (37.1 %) showed atrophic lesions. In 42 children (36.2 %), we observed affections of the paranasal sinuses.

CONCLUSION

The imaging findings requiring immediate treatment even though the children did not show any clinical signs, justify cerebral MR examinations prior to stem cell transplantation.

Mechanisms of electrically mediated cytosolic Ca2+ transients in aequorin-transformed tobacco cells

Cytosolic Ca(2+) changes induced by electric field pulses of 50-micros duration and 200-800 V/cm strength were monitored by measuring chemiluminescence in aequorin-transformed BY-2 tobacco cells. In Ca(2+)-substituted media, electropulsing led to a very fast initial increase of the cytosolic Ca(2+) concentration reaching a peak value within <100-200 ms. Peaking of [Ca(2+)](cyt) was followed by a biphasic decay due to removal of Ca(2+) (e.g., by binding and/or sequestration in the cytosol). The decay had fast and slow components, characterized by time constants of approximately 0.5 and 3-5 s, respectively. Experiments with various external Ca(2+) concentrations and conductivities showed that the fast decay arises from Ca(2+) fluxes through the plasmalemma, whereas the slow decay must be assigned to Ca(2+) fluxes through the tonoplast. The amplitude of the [Ca(2+)](cyt) transients increased with increasing field strength, whereas the time constants of the decay kinetics remained invariant. Breakdown of the plasmalemma was achieved at a critical field strength of approximately 450 V/cm, whereas breakdown of the tonoplast required approximately 580 V/cm. The above findings could be explained by the transient potential profiles generated across the two membranes in response to an exponentially decaying field pulse. The dielectric data required for calculation of the tonoplast and plasmalemma potentials were derived from electrorotation experiments on isolated vacuolated and evacuolated BY-2 protoplasts. The electrorotation response of vacuolated protoplasts could be described in terms of a three-shell model (i.e., by assuming that the capacitances of tonoplast and plasmalemma are arranged in series). Among other things, the theoretical analysis together with the experimental data show that genetic manipulations of plant cells by electrotransfection or electrofusion must be performed in low-conductivity media to minimize release of vacuolar Ca(2+) and presumably other vacuolar ingredients.

Expression of proliferation marker Ki67 correlates to occurrence of metastasis and prognosis, histological subtypes and HPV DNA detection in penile carcinomas

Clinical outcome of penile squamous cell carcinoma (PSCC) largely depends on the presence of lymph node metastasis. In search of a valuable marker predicting the risk for metastasis, the expression of Ki67 was investigated immunohistochemically in primary tumors and compared to presence of inguinal lymph node metastasis. As human papilloma virus (HPV) is thought to affect Ki67 expression, we evaluated whether occurrence of HPV DNA correlates to Ki67 score or metastatic potential. Samples originated from patients subjected to resection of invasive SCC of penis. Immunohistochemistry was done on paraffin-embedded sections using a monoclonal antibody against Ki67. After DNA isolation from paraffin embedded tissue the presence of HPV 6/11, HPV 16 and HPV 18 DNA was analyzed by PCR. Statistical analysis was done using two tail unpaired t test and Chi-square test. Four of 28 patients showed a weak Ki67 expression, without displaying lymph node metastasis. Among 17 patients showing an intermediate Ki67 index, eight exhibited metastases while in all seven patients with a strong expression of Ki67 lymph node metastases were found. The median Ki67 expression in metastastic lesions was significantly different (50.3%) from tumors without lymph node metastasis (31.8%) (p=0.024). Furthermore, a correlation between presence of HPV DNA and strong Ki67 expression was determined (p=0.009). Since our study demonstrated a strong Ki67 labeling index significantly associated to positive lymph nodes, we suggest Ki67 expression as a prognostic marker for lymph node metastasis in penile squamous carcinoma.

[Establishing a protein signature from prostate tissue biopsies]

The prostate-specific antigen test (PSA) has been a major factor contributing to a better management of prostate cancer. The low specificity limits its use in diagnosis especially in early detection of prostate cancer. Multiply expressed proteins need to be identified to establish a disease-specific protein signature that distinguishes between cancerous and noncancerous tissue. The first aim of our study is to identify differentially expressed proteins in both tissues using two-dimensional gel electrophoresis and subsequent mass spectrometry. We elucidated whether prostate biopsies are useful. First results have shown a different protein expression pattern in cancerous and noncancerous tissue. PCR revealed an increasing amount of mRNA for some upregulated proteins. We conclude that biopsies are useful material to establish protein expression patterns.