Minimally invasive approach to pelvic organ prolapse: a review.

Uterovaginal prolapse, vaginal vault prolapse, and rectal prolapse are pelvic floor support problems that have been traditionally addressed through abdominal, vaginal or perineal approaches. Over the past decade, minimally invasive approaches to these procedures have been reported and refined. We discuss both laparoscopic and robotic techniques for repair of uterovaginal prolapse, vaginal vault prolapse, and rectal prolapse. In addition, we summarize currently available success and complication data associated with each technique.

Use of green fluorescent protein-based reporters to monitor balanced production of antifungal compounds in the biocontrol agent Pseudomonas fluorescens CHA0.

AIMS: To develop reporter constructs based on stable and unstable variants of the green fluorescent protein (GFP) for monitoring balanced production of antifungal compounds that are crucial for the capacity of the root-colonizing Pseudomonas fluorescens strain CHA0 to control plant diseases caused by soil-borne pathogenic fungi. METHODS AND RESULTS: Pseudomonas fluorescens CHA0 produces the three antifungal metabolites 2,4-diacetylphloroglucinol (DAPG), pyoluteorin (PLT) and pyrrolnitrin (PRN). The gfp[mut3] and gfp[AAV] reporter genes were fused to the promoter regions of the DAPG, PLT and PRN biosynthetic genes. The reporter fusions were then used to follow the kinetics of expression of the three antifungal metabolites in a microplate assay. DAPG and PLT were found to display an inverse relationship in which each metabolite activates its own biosynthesis while repressing the synthesis of the other metabolite. PRN appears not to be involved in this balance. However, the microbial and plant phenolic metabolite salicylate was found to interfere with the expression of both DAPG and PLT. CONCLUSIONS: The results obtained provide evidence that P. fluorescens CHA0 may keep the antifungal compounds DAPG and PLT at a fine-tuned balance that can be affected by certain microbial and plant phenolics. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, the present study is the first to use stable and unstable GFP variants to study antibiotic gene expression in a biocontrol pseudomonad. The developed reporter fusions will be a highly valuable tool to study in situ expression of this bacterial biocontrol trait on plant roots, i.e. at the site of pathogen suppression.

Expertise training with novel objects leads to left-lateralized facelike electrophysiological responses.

Scalp event-related potentials (ERPs) in humans indicate that face and object processing differ approximately 170 ms following stimulus presentation, at the point of the N170 occipitotemporal component. The N170 is delayed and enhanced to inverted faces but not to inverted objects. We tested whether this inversion effect reflects early mechanisms exclusive to faces or whether it generalizes to other stimuli as a function of visual expertise. ERPs to upright and inverted faces and novel objects (Greebles) were recorded in 10 participants before and after 2 weeks of expertise training with Greebles. The N170 component was observed for both faces and Greebles. The results are consistent with previous reports in that the N170 was delayed and enhanced for inverted faces at recording sites in both hemispheres. For Greebles, the same effect of inversion was observed only for experts, primarily in the left hemisphere. These results suggest that the mechanisms underlying the electrophysiological face-inversion effect extend to visually homogeneous nonface object categories, at least in the left hemisphere, but only when such mechanisms are recruited by expertise.

Calcium as a modulator of photosensitized killing of H9c2 cardiac cells.

Illumination of H9c2 rat heart cells in the presence of Rose Bengal resulted in dose-dependent cell killing (assessed by trypan blue staining) and modification of ionic currents flowing through the heart cell membrane. Inhibitors of voltage-gated ionic currents were shown to have little effect on cell killing. Ionic current measurements were used to assess the increase in leak conductance of these cells, which has been suggested to be a causal factor in killing of other cell types (1). Inhibitors of voltage-gated ionic currents, including the sodium channel blocker tetrodotoxin (100 microM) and the calcium channel blocker lanthanum (10 microM) were shown to have little effect on cell killing. The potassium channel inhibitor tetraethylammonium (20 mM) inhibited cell killing, but the effect is viewed as being caused by an inhibition of leak current. The time course of block of voltage-activated ionic currents during illumination, in the presence of Rose Bengal, was rapid compared with that for induction of leak current and for cell killing. These observations are consistent with a role for leak current in photosensitized killing of cardiac cells. They are interpreted with respect to calcium influx through the leak current pathway as a trigger for the cellular response.

Mechanisms of ammonia and amino acid photoproduction from aquatic humic and colloidal matter.

Photochemical release of free amino acids was observed from dissolved fulvic acid (Suwannee River) and from colloidal fractions collected from Bayou Trepagnier, LA. Water samples were irradiated with a solar simulator, and free amino acid concentrations were determined using high performance liquid chromatography of the fluorescent derivitized amino acids. Increased concentrations of at least 20 amines were observed upon irradiation of water samples. Among the amino acids identified were alanine, asparagine, citrulline, glutamic acid, histidine, norvaline, and serine. Amino acid concentrations increased in the range of 0.03-9.5 nM h(-1). Studies on the mechanism of photochemical release of ammonia from dissolved natural organic matter (NOM) indicated at least two mechanisms. One mechanism proceeds through an hydroxyl radical intermediate. This mechanism continues in the dark after irradiation through decomposition of photochemically produced H2O2 to form hydroxyl radical. Although NOM photosensitized degradation of amino acids produces ammonia, amino acids do not appear to be an important intermediate in the photochemical formation of ammonia from NOM.

Aqueous sonolytic decomposition of polycyclic aromatic hydrocarbons in the presence of additional dissolved species.

Sonochemical degradation of aqueous polycyclic aromatic hydrocarbons (PAHs) results in a first-order loss of the PAHs (k = 0.010-0.027 s-1). When sonication occurred in the presence of other organic compounds, the degradation rate constant was reduced quite dramatically. This reduction is believed to come about through scavenging of radicals by the matrix chemical. When oxygen was bubbled into the PAH solution before sonication, the degradation rate constant was elevated. Nitrogen purging resulted in decreased rate constants. These results indicate that oxygen was an important precursor in the degradation of the PAHs. Organic compounds, including humic acid, benzoic acid, and sodium dodecyl sulfate, decreased PAH degradation rate constants by scavenging oxygen derived reactive transients.

What defines a view?

At a given instant we see only visible surfaces, not an object's complete 3D appearance. Thus, objects may be represented as discrete 'views' showing only those features visible from a limited range of viewpoints. We address how to define a view using Koenderink's (Koenderink & Van Doorn, Biol. Cybernet. 32 (1979) 211.) geometric method for enumerating complete sets of stable views as aspect graphs. Using objects with known aspect graphs, five experiments examined whether the perception of orientation is sensitive to the qualitative features that define aspect graphs. Highest sensitivity to viewpoint changes was observed at locations where the theory predicts qualitative transitions, although some transitions did not affect performance. Hypotheses about why humans ignore some transitions offer insights into mechanisms for object representation.

Photosensitization-induced calcium overload in cardiac cells: direct link to membrane permeabilization and calcium influx.

The purpose of the present study was to gain new insight regarding the role membrane permeabilization plays in the photosensitization-induced increase in intracellular calcium concentration. During continuous rose bengal photosensitization we monitored the contractile state (relaxed or hypercontracted) of isolated frog cardiac cells and assessed the photosensitization-induced membrane-leak conductance. We investigated the effects of irradiance, extracellular calcium concentration, intracellular chelation of calcium and substitution of tetraethylammonium (TEA) for extracellular sodium. We found that with 2 and 5 mM extracellular calcium cell hypercontracture occurred when leak conductance reached values on the order of 6-7 nS, independent of the illumination duration required to reach this conductance. With 0.5 mM calcium hypercontracture occurred when leak conductance reached values on the order of 11 nS. Chelation of intracellular calcium delayed the onset of cell hypercontracture and increased by two- to three-fold the leak conductance at the initiation of cell hypercontracture. Substitution of TEA for extracellular sodium did not affect the time to contracture onset but reduced leak conductance at contracture onset nearly three-fold. We discuss how our results support the conclusion that photosensitization induces an increase in intracellular calcium concentration via calcium influx through the transmembrane-permeability pathway opened by the photosensitization process.

Perceptual categorization of cat and dog silhouettes by 3- to 4-month-old infants.

Given evidence that silhouette information can be used by adults to form categorical representations at the basic level, four experiments utilizing the familiarization-novelty preference procedure were performed to examine whether 3- and 4-month-old infants could form categorical representations for cats versus dogs from the perceptual information available in silhouettes (e.g., global shape and external outline). Experiments 1 and 2 showed that infants could form individuated categorical representations for cat and dog silhouettes, whereas Experiments 3 and 4 revealed that infants could use silhouette information from the head, but not the body, to categorically separate the two species. These results indicate that general shape or external contour information that is centered about the head is sufficient for young infants to form individuated categorical representations for cats and dogs. The data thus provide information regarding the nature of the perceptual information that can be used by infants to form category representations for individual animal species and are discussed in terms of domain-general versus domain-specific processing accounts.

Quantitation of hydroxyl radical during fenton oxidation following a single addition of iron and peroxide.

Chemical probes were used to study the formation of hydroxyl radical in aqueous iron-hydrogen peroxide reaction. Hydroxyl radical formation rate and time dependent concentration were determined in pure water, in aqueous fulvic acid (FA) and humic acid (HA) solutions, and in natural surface waters. Indirect determinations of hydroxyl radical were made by quantitating hydroxyl radical reactions with probe compounds under controlled conditions. High probe concentrations were used to determine radical formation rates and low probe concentrations were used to determine time dependent radical concentration. Two independent probes were used for intercomparison: benzoic acid and 1-propanol. Good agreement between the two probes was observed. Natural water matrices resulted in lower radical formation rates and lower hydroxyl radical concentrations, with observed formation rate and yield in natural waters up to four times lower than in pure water. HA and FA also reduced hydroxyl radical formation under most conditions, although increased radical formation was observed with FA at certain pH values. Hydroxyl radical formation increased linearly with hydrogen peroxide concentration.

The fusiform "face area" is part of a network that processes faces at the individual level.

According to modular models of cortical organization, many areas of the extrastriate cortex are dedicated to object categories. These models often assume an early processing stage for the detection of category membership. Can functional imaging isolate areas responsible for detection of members of a category, such as faces or letters? We consider whether responses in three different areas (two selective for faces and one selective for letters) support category detection. Activity in these areas habituates to the repeated presentation of one exemplar more than to the presentation of different exemplars of the same category, but only for the category for which the area is selective. Thus, these areas appear to play computational roles more complex than detection, processing stimuli at the individual level. Drawing from prior work, we suggest that face-selective areas may be involved in the perception of faces at the individual level, whereas letter-selective regions may be tuning themselves to font information in order to recognize letters more efficiently.

The N170 occipito-temporal component is delayed and enhanced to inverted faces but not to inverted objects: an electrophysiological account of face-specific processes in the human brain.

Behavioral studies have shown that picture-plane inversion impacts face and object recognition differently, thereby suggesting face-specific processing mechanisms in the human brain. Here we used event-related potentials to investigate the time course of this behavioral inversion effect in both faces and novel objects. ERPs were recorded for 14 subjects presented with upright and inverted visual categories, including human faces and novel objects (Greebles). A N170 was obtained for all categories of stimuli, including Greebles. However, only inverted faces delayed and enhanced N170 (bilaterally). These observations indicate that the N170 is not specific to faces, as has been previously claimed. In addition, the amplitude difference between faces and objects does not reflect face-specific mechanisms since it can be smaller than between non-face object categories. There do exist some early differences in the time-course of categorization for faces and non-faces across inversion. This may be attributed either to stimulus category per se (e.g. face-specific mechanisms) or to differences in the level of expertise between these categories.

[Alteration of nitric oxide production during arterial myocardial revascularization using extracorporeal circulation. Quantitative measurement of EDNO production by the internal mammary artery bypass graft]. / A nitrogén-monoxid (NO) metabolizmusának változása extracorporalis keringésben végzett artériás myocardium-revascularisatio során. Az arteria mammaria interna bypass graft endotheliumából származó anyag (EDNO) kiválasztásának mennyiségi mérése.

Authors measured the concentration of stable metabolite (NO2: nitrite) of EDNO (endothelium derived nitric oxide) in the internal mammary artery (IMA) bypass graft with the help of a previously reported method (measurement of effective blood flow capacity of the IMA graft in the coronary sinus). Nitrite level in the systemic circulation prior to extracorporeal circulation (ECC)--(68.1 +/- 6.7 mumol/l) was measured, as well as nitrite concentration in the coronary circulation before and after construction of the IMA bypass graft (62.1 +/- 4.19 mumol/l and 50.26 +/- 4.0 mumol/l respectively). Furthermore, nitrite level in the IMA graft free cut end flow was also determined (64.3 +/- 5.9 mumol/l). These data compared to the nitrite levels in the normal plasma (48.1 +/- 5.9 mumol/l) were found to be higher (p = 0.1, ns.), possibly due to the enhanced EDNO production induced by total heparinization. The nitrite concentration in the IMA free cut end flow is similar or slightly higher than that of the native coronary circulation, however, after IMA bypass construction a relative reduction could be measured in the coronary sinus. Authors believe, that this may be related to the reduction of basal EDNO production caused by supernormal pO2 (215 +/- 19 mmHg) during ECC.

Does visual subordinate-level categorisation engage the functionally defined fusiform face area?

Functional magnetic resonance imaging was used to compare brain activation associated with basic-level (e.g. bird) and subordinate-level (e.g. eagle) processing for both visual and semantic judgements. We localised the putative face area for 11 subjects, who also performed visual matching judgements for pictures and aurally presented words. The middle fusiform and occipital gyri were recruited for subordinate minus basic visual judgements, reflecting additional perceptual processing. When the face area was localised individually for each subject, analyses in the middle fusiform gyri revealed that subordinate-level processing activated the individuals face area. We propose that what is unique about the way faces engage this region is the focal spatial distribution of the activation rather than the recruitment of the face per se. Eight subjects also performed semantic judgements on aurally presented basic- and subordinate-level words. The parahippocampal gyri were more activated for subordinate-level than basic-level semantic judgements. Finally, the left posterior inferior temporal gyrus was activated for subordinate-level judgements, both visual and semantic, as well as during passive viewing of faces.

News on views: pandemonium revisited.

How do we recognize objects from different viewpoints? A new model, based on the known properties of cortical neurons, may help resolve this long-standing debate.

Dissolved organic matter inhibition of sonochemical degradation of aqueous polycyclic aromatic hydrocarbons.

Sonochemical degradation of aqueous polycyclic aromatic hydrocarbons (PAHs) was found to be rapid in the absence of other dissolved compounds (k = 0.006-0.015 s-1). In the presence of 20 mg Cl-1 fulvic acid, first-order PAH degradation rate constants decreased from 2.3- to 3.7-fold. Similar results were obtained with added benzoic acid, a crude analog for fulvic acid. In natural waters, PAH degradation was almost completely inhibited. Analysis of the kinetic behavior and reaction products indicates that PAHs are most likely degraded through a radical cation mechanism. Hydroxyl radical appeared to play an insignificant role in the degradation. Inhibited degradation was probably the result of either altered cavitation processes or isolation of the PAH away from cavitation sites.

Can face recognition really be dissociated from object recognition?

We argue that the current literature on prosopagnosia fails to demonstrate unequivocal evidence for a disproportionate impairment for faces as compared to nonface objects. Two prosopagnosic subjects were tested for the discrimination of objects from several categories (face as well as nonface) at different levels of categorization (basic, subordinate, and exemplar levels). Several dependent measures were obtained including accuracy, signal detection measures, and response times. The results from Experiments 1 to 4 demonstrate that, in simultaneous-matching tasks, response times may reveal impairments with nonface objects in subjects whose error rates only indicate a face deficit. The results from Experiments 5 and 6 show that, given limited stimulus presentation times for face and nonface objects, the same subjects may demonstrate a deficit for both stimulus categories in sensitivity. In Experiments 7, 8 and 9, a match-to-sample task that places greater demands on memory led to comparable recognition sensitivity with both face and nonface objects. Regardless of object category, the prosopagnosic subjects were more affected by manipulations of the level of categorization than normal controls. This result raises questions regarding neuropsychological evidence for the modularity of face recognition, as well as its theoretical and methodological foundations.

Orientation-specific possibility priming for novel three-dimensional objects.

Priming effects on the object possibility task, in which participants decide whether line drawings could or could not be possible three-dimensional objects, may be supported by the same processes and representations used in recognizing and identifying objects. Three experiments manipulating objects' picture-plane orientation provided limited support for this hypothesis. Like old/new recognition performance, possibility priming declined as study-test orientation differences increased from 0 degree to 60 degrees. However, while significant possibility priming was not observed for larger orientation differences, recognition performance continued to decline following 60 degrees-180 degrees orientation shifts. These results suggest that possibility priming and old/new recognition may rely on common viewpoint-specific representations but that access to these representations in the possibility test occurs only when study and test views are sufficiently similar (i.e., rotated less than 60 degrees).