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PubMed1992

Normal and Abnormal Development in the Arabidopsis Vegetative Shoot Apex.

Vegetative development in the Arabidopsis shoot apex follows both sequential and repetitive steps. Early in development, the young vegetative meristem is flat and has a rectangular shape with bilateral symmetry. The first pair of leaf primordia is radially symmetrical and is initiated on opposite sides of the meristem. As development proceeds, the meristem changes first to a bilaterally symmetrical trapezoid and then to a radially symmetrical dome. Vegetative development from the domed meristem continues as leaves are initiated in a repetitive manner. Abnormal development of the vegetative shoot apex is described for a number of mutants. The mutants we describe fall into at least three classes: (1) lesions in the shoot apex that do not show an apparent alteration in the shoot apical meristem, (2) lesions in the apical meristem that also (directly or indirectly) alter leaf primordia, and (3) lesions in the apical meristem that alter meristem size and leaf number but not leaf morphology. These mutations provide tools both to genetically analyze vegetative development of the shoot apex and to learn how vegetative development influences floral development.

Journal Article↗

PubMed1995

Sink limitation induces the expression of multiple soybean vegetative lipoxygenase mRNAs while the endogenous jasmonic acid level remains low.

The response of individual members of the lipoxygenase multigene family in soybeans to sink deprivation was analyzed. RNase protection assays indicated that a novel vegetative lipoxygenase gene, vlxC, and three other vegetative lipoxygenase mRNAs accumulated in mature leaves in response to a variety of sink limitations. These data suggest that several members of the lipoxygenase multigene family are involved in assimilate partitioning. The possible involvement of jasmonic acid as a signaling molecule regulating assimilate partitioning into the vegetative storage proteins and lipoxygenases was directly assessed by determining the endogenous level of jasmonic acid in leaves from plants with their pods removed. There was no rise in the level of endogenous jasmonic acid coincident with the strong increase in both vlxC and vegetative storage protein VspB transcripts in response to sink limitation. Thus, expression of the vegetative lipoxygenases and vegetative storage proteins is not regulated by jasmonic acid in sink-limited leaves.

Amino Acid Sequence↗

PubMed1999

Protective effect of allium vegetables against both esophageal and stomach cancer: a simultaneous case-referent study of a high-epidemic area in Jiangsu Province, China.

To study the relation between allium vegetable intake and cancer of the esophagus (EC) and stomach (SC) in Yangzhong city, which is one of the highest-risk areas for these cancers in Jiangsu province, China, a simultaneous case-referent study was conducted using histopathologically confirmed cases (EC: n = 81, SC: n = 153) and population-based referents (n = 234). A questionnaire was used to collect information on the general status of subjects, their dietary habits, frequency intake of allium vegetables and other foods, tea consumption, smoking and alcohol drinking. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by a multiple logistic regression model. The results showed that frequent intake of allium vegetables (including garlic, onion, Welsh onion and Chinese chives), raw vegetables, tomatoes and snap beans, and tea consumption were inversely associated with the risk for EC and SC. In the highest consumption category (> or = 1 time/week) of garlic, onion, Welsh onion and Chinese chives, the adjusted ORs compared with the lowest category (< 1 time/month) were 0.30 (CI = 0.19-0.47), 0.25 (CI = 0.11-0.54), 0.15 (CI = 0.08-0.26), and 0.57 (CI = 0.23-1.42) for EC, and 0.31 (CI = 0.22-0.44), 0.17 (CI = 0.08-0.36), 0.22 (CI = 0.15-0.31) and 0.40 (CI = 0.17-0.94) for SC, respectively. The main results in the present study suggested that allium vegetables, like raw vegetables, may have an important protecting effect against not only stomach cancer, but also esophageal cancer.

Adult↗

PubMed1993

Vegetable versus animal protein diet in cirrhotic patients with chronic encephalopathy. A randomized cross-over comparison.

In a randomized cross-over comparison, the effects of a mainly vegetable protein diet were compared with an animal protein diet in eight patients with cirrhosis and chronic permanent encephalopathy, under optimum lactulose therapy. After a run-in period, patients were fed two equi-caloric, equi-nitrogenous diets for 7 days (71 g total proteins), containing either 50 g protein of animal origin or 50 g vegetable proteins. In the last 3 days of each period, nitrogen balance was significantly better during the vegetable protein diet (+0.2 (SD 1.4) g vs. -1.7 (2.4); P < 0.01), the difference being entirely due to a reduced urinary nitrogen excretion. Average daytime integrated blood glucose was slightly higher during vegetable proteins, whereas insulin, plasma amino acids and ammonia were lower. The clinical grading of encephalopathy improved slightly on vegetable proteins, and psychometric tests improved significantly, but remained grossly abnormal. Compliance to dietary manipulation was good. The data prove that a mainly vegetable protein diet is worthwhile in cirrhotic patients with chronic encephalopathy under optimum lactulose therapy. Improved nitrogen balance may be related to more effective nitrogen use for protein synthesis, probably due to blunted hormonal response, and largely outweighs the effects on encephalopathy.

Aged↗

PubMed1980

31P NMR studies of vegetative and encysted cells of Acanthamoeba castellanii. Observation of phosphonic acids in live cells.

31P NMR studies have been performed on vegetative and encysted Acanthamoeba castellanii. A prominent feature of the spectra is the presence of resonances characteristic of P-C linkages. Vegetative cells show sharp phosphonate resonances whereas encysted cells show broad phosphonate resonances and narrow phosphate resonances. Studies of model compounds using 31P NMR have shown the narrow resonances to arise from 2-aminoethylphosphonic acid; the broad components from encysted cells arise from molecules with long rotational correlation times such as aggregates of lipophosphonoglycan or phosphonoprotein. Vegetative cells also show the presence of an electronegatively beta-substituted phosphonic acid, possibly 1-hydroxy-2-aminoethylphosphonic acid, a component identified in the cell membrane lipophosphoglycan. pH titration studies of a number of phosphonic acid model compounds show a chemical shift behaviour quite distinct from that of biological phosphates. Upon acidification from pH 12, resonances shift to high field followed by return to lower field at pH 1.0. These resonances can be ambiguous as monitors of cellular pH. The pH of both vegetative and encysted cells is 6.0--6.5. Encysted cells under anaerobic conditions show no spectral changes over 24 h. Vegetative cells under similar conditions show time-dependent changes characteristic of variation in cellular pH. There appears to be little correlation between pH and the variously differentiated states (vegetative or encysted) in Acanthamoeba.

Amoeba↗

PubMed2006

Transvenous pacemaker lead removal is safe and effective even in large vegetations: an analysis of 53 cases of pacemaker lead endocarditis.

BACKGROUND: The aim of this study was to investigate whether transvenous lead removal is safe and effective in patients with lead vegetations greater than 1 cm in size. METHODS: From 1991 to 2005, a total of 53 patients underwent pacemaker or ICD lead removal for vegetations. Transvenous lead removal using locking stylets and sheaths was performed in 30 patients (56.6%) and was found to be effective in 29 of those patients. In 1 patient, due to rupture of the lead, open heart removal of the ventricular lead remnant and tricuspid valve repair had to be performed due to persistent infection. In 23 of these patients, transesophageal echocardiography (TEE) verified vegetations greater than 1 cm in size. The remaining patients underwent primary lead removal using sternotomy and extracorporeal circulation (ECC). Pacemaker pocket infection was found in 16 patients (55.2%) of the transvenous study group and in 11 patients (45.8%) of the ECC group (P = 0.72). RESULTS: Perioperative mortality was 5.7% (3 patients); all of them underwent primary ECC removal and had severe endocarditis of the tricuspid valve. None of the patients who underwent transvenous lead removal died and there were no further complications such as pericardial tamponade or major pulmonary embolism requiring further interventions, even in patients demonstrating large vegetations. CONCLUSIONS: This study demonstrates that transvenous lead removal is a safe and highly effective procedure for the removal of infected pacemaker and ICD leads, even in patients with large vegetations. Embolism to the lung proceeds mainly without further complications; however, patients with vegetations that might obstruct a main stem of the pulmonary artery should undergo ECC removal.

Aged↗

PubMed1985

Comparative pharmacokinetics of ceftazidime in fibrin clots and cardiac vegetations in rabbits with Staphylococcus aureus endocarditis.

The penetration of ceftazidime, administered in a dose of 100 mg/kg intramuscularly, into cardiac vegetations and subcutaneously implanted fibrin clots was compared in rabbits with experimental Staphylococcus aureus endocarditis. Significant pharmacokinetic differences between the time-concentration curves for the two compartments were observed. Concentrations of ceftazidime in vegetations peaked at 30 min after dosing at a level slightly lower than that in plasma and thereafter declined in parallel with concentrations in plasma throughout the 8-h sampling period. Concentrations in fibrin clots increased more slowly than those in plasma and vegetations, reaching a maximum at 120 min. This was followed by a slow elimination phase yielding concentrations in excess of concurrent plasma and vegetation levels and a greater area under the curve. These features were observed for both large (2-ml volume) and small (0.1-ml volume) clots. Contrary to previous reports, these observations suggest that fibrin clots do not provide an accurate model for predicting antibiotic concentrations in cardiac vegetations produced in endocarditis and that concentrations of antimicrobial agents in vegetations can be predicted more accurately from concomitant plasma levels.

Animals↗

PubMed1994

In vivo activities and penetration of the two components of the streptogramin RP 59500 in cardiac vegetations of experimental endocarditis.

We evaluated the in vivo activity and the diffusion of radiolabelled RP 57669 (RPI) and RP 54476 (RPII), the two components of the injectable streptogramin RP 59500, alone or in combination, in aortic vegetations from experimental endocarditis in rabbits. RPI and RPII demonstrated in vitro bacteriostatic and bactericidal synergy against a clinical strain of Staphylococcus aureus resistant to methicillin and susceptible to erythromycin. In experimental staphylococcal endocarditis, RP 59500 was as effective as vancomycin and significantly more effective than RPI (P < 0.01) and RPII (P < 0.05). Autoradiography studies showed different patterns of distribution into cardiac vegetations infected with Streptococcus sanguis for [14C]RPI and [14C]RPII. [14C]RPI was homogeneously distributed throughout the vegetations whereas [14C]RPII showed a decreasing gradient of concentration between the periphery and the core of the vegetation, with an approximately 2:1 ratio. [14C]RPI diffused approximately 2 to 4 times more than [14C]RPII into the core of the vegetations. Since the injected ratio of RPI and RPII is 30:70 in RP 59500, the actual RPI:RPII ratio in the core of the vegetation may range from 0.8 to 1.7, a ratio which remains compatible with the in vivo synergism demonstrated between the two components.

Animals↗

PubMed1974

Role of the vegetation in experimental Streptococcus viridans endocarditis.

This study examines the role of the vegetation in catheter-induced experimental endocarditis in predisposing to bacterial colonization of cardiac valves and in influencing the course of the disease and response to penicillin therapy. Platelet-fibrin vegetations developed at areas of valvular trauma and were colonized when Streptococcus viridans were injected intravenously. Pretreatment with warfarin prevented vegetation formation, but animals still developed endocarditis at the same rate after injection of 10(6)S. viridans. The course of the disease in anticoagulated animals was more explosive, as determined by a more rapid rise in fever and level of bacteremia. Mean survival was shorter in anticoagulated rabbits (7 versus 12.7 days). Large vegetations containing 10(9)S. viridans/g were found in control animals, whereas anticoagulated rabbits developed only microscopic deposits. Large vegetations required a longer duration of penicillin therapy to sterilize than the infected valves of the anticoagulated group (7 versus 3 days). Therefore, a preformed platelet-fibrin deposit is not a prerequisite for bacterial colonization of cardiac valves. After infection, the vegetation is an important factor in determining the subacute course of disease and resistance to penicillin therapy.

Animals↗

PubMed1981

Reliability and clinical relevance of detection of vegetations by echocardiography in bacterial endocarditis.

The efficacy of M-mode echocardiography in identifying vegetations and the clinical relevance of such a finding were evaluated in 36 patients with bacterial endocarditis, 18 of whom had pre-existing valvar lesions. Of 22 patients with vegetations demonstrated by echocardiography, 21 had major complications of bacterial endocarditis and eight died, whereas only eight of the 14 patients without detectable vegetations had similar complications and only two died. Nine of the 11 patients with pre-existing valvar lesions and echocardiographic evidence of vegetations came to operation or necropsy, and in eight of these the presence of vegetations was confirmed. In the other, none was found at surgery performed after an interval of six months. M-mode echocardiography can reliably detect vegetations in patients with bacterial endocarditis even in the presence of pre-existing valvar lesions, and may permit the identification of a subset of high risk patients who may need early surgery.

Adolescent↗

PubMed2006

The Transtheoretical model for fruit, vegetable and fish consumption: associations between intakes, stages of change and stage transition determinants.

BACKGROUND: Cardiovascular diseases are caused by multiple behavioral factors, including different dietary factors. We examined to what extent fruit, vegetable and fish consumption are related, and whether behavioral determinants vary across these dietary behaviors from a Transtheoretical model perspective. METHODS: Data were collected among 1142 participants (T0; response rate 46%) selected from an Internet panel, who were followed-up one-week later (T1; N = 1055, response rate 92%). Mean age was 35.4 (SD = 11.9) years, 35% was male, and most respondents were of Dutch origin (90%). Of the respondents, 13%, 44% and 43% had a low, medium or high level of education, respectively. Electronic questionnaires assessed fruit, vegetable and fish intake (food frequency questionnaires), stages of change, decisional balance and self-efficacy, for each of these three behaviors. RESULTS: Stages of change and (changes in) fruit, vegetable and fish intake were only weakly associated; decisional balance and self-efficacy were more strongly associated. Some presumed predictors of stage transitions were similar for fruit, vegetable, and fish intake, i.e., strong pros predicted progress out of precontemplators and low self-efficacy predicted relapse from action/maintenance for all behaviors. However, progress out of contemplation and out of preparation showed different patterns for fruit, vegetable and fish intake. CONCLUSION: The weak associations between intakes and potential determinants for fruit, vegetable, and fish consumption do not warrant an integrated dietary change approach targeting the same determinants for each behavior.

Journal Article↗

PubMed2006

Terrestrial vegetation redistribution and carbon balance under climate change.

BACKGROUND: Dynamic Global Vegetation Models (DGVMs) compute the terrestrial carbon balance as well as the transient spatial distribution of vegetation. We study two scenarios of moderate and strong climate change (2.9 K and 5.3 K temperature increase over present) to investigate the spatial redistribution of major vegetation types and their carbon balance in the year 2100. RESULTS: The world's land vegetation will be more deciduous than at present, and contain about 125 billion tons of additional carbon. While a recession of the boreal forest is simulated in some areas, along with a general expansion to the north, we do not observe a reported collapse of the central Amazonian rain forest. Rather, a decrease of biomass and a change of vegetation type occurs in its northeastern part. The ability of the terrestrial biosphere to sequester carbon from the atmosphere declines strongly in the second half of the 21st century. CONCLUSION: Climate change will cause widespread shifts in the distribution of major vegetation functional types on all continents by the year 2100.

Journal Article↗

PubMed1997

Identification and localization of a sea urchin Notch homologue: insights into vegetal plate regionalization and Notch receptor regulation.

The specifications of cell types and germ-layers that arise from the vegetal plate of the sea urchin embryo are thought to be regulated by cell-cell interactions, the molecular basis of which are unknown. The Notch intercellular signaling pathway mediates the specification of numerous cell fates in both invertebrate and vertebrate development. To gain insights into mechanisms underlying the diversification of vegetal plate cell types, we have identified and made antibodies to a sea urchin homolog of Notch (LvNotch). We show that in the early blastula embryo, LvNotch is absent from the vegetal pole and concentrated in basolateral membranes of cells in the animal half of the embryo. However, in the mesenchyme blastula embryo LvNotch shifts strikingly in subcellular localization into a ring of cells which surround the central vegetal plate. This ring of LvNotch delineates a boundary between the presumptive secondary mesoderm and presumptive endoderm, and has an asymmetric bias towards the dorsal side of the vegetal plate. Experimental perturbations and quantitative analysis of LvNotch expression demonstrate that the mesenchyme blastula vegetal plate contains both animal/vegetal and dorsoventral molecular organization even before this territory invaginates to form the archenteron. Furthermore, these experiments suggest roles for the Notch pathway in secondary mesoderm and endoderm lineage segregation, and in the establishment of dorsoventral polarity in the endoderm. Finally, the specific and differential subcellular expression of LvNotch in apical and basolateral membrane domains provides compelling evidence that changes in membrane domain localization of LvNotch are an important aspect of Notch receptor function.

Amino Acid Sequence↗

PubMed1997

Microtubule disruption reveals that Spemann's organizer is subdivided into two domains by the vegetal alignment zone.

Mediolateral cell intercalation is proposed to drive morphogenesis of the primary embryonic axis in Xenopus. Mediolateral intercalation begins in a group of cells called the vegetal alignment zone, a subpopulation of cells in Spemann's organizer, and spreads through much of the marginal zone. To understand the functions of the vegetal alignment zone during gastrulation and axis formation, we have inhibited its formation by disrupting microtubules with nocodazole in early gastrula embryos. In such embryos, mediolateral intercalation, involution and convergent extension of the marginal zone do not occur. Although cell motility continues, and the anterior notochordal and somitic mesoderm differentiate in the pre-involution marginal zone, posterior notochordal and somitic mesoderm do not differentiate. In contrast, microtubule depolymerization in midgastrula embryos, after the vegetal alignment zone has formed, does not inhibit mediolateral cell intercalation, involution and convergent extension, or differentiation of posterior notochord and somites. We conclude that microtubules are required only for orienting and polarizing at stage 101/2 the first cells that undergo mediolateral intercalation and form the vegetal alignment zone, and not for subsequent morphogenesis. These results demonstrate that microtubules are required to form the vegetal alignment zone, and that both microtubules and the vegetal alignment zone play critical roles in the inductive and morphogenetic activities of Spemann's organizer. In addition, our results suggest that Spemann's organizer contains multiple organizers, which act in succession and change their location and function during gastrulation to generate the anterior/posterior axis in Xenopus.

Animals↗

PubMed1999

Anteroposterior patterning of the epidermis by inductive influences from the vegetal hemisphere cells in the ascidian embryo.

Patterning along the anteroposterior axis is a critical step during animal embryogenesis. Although mechanisms of anteroposterior patterning in the neural tube have been studied in various chordates, little is known about those of the epidermis. To approach this issue, we investigated patterning mechanisms of the epidermis in the ascidian embryo. First we examined expression of homeobox genes (Hrdll-1, Hroth, HrHox-1 and Hrcad) in the epidermis. Hrdll-1 is expressed in the anterior tip of the epidermis that later forms the adhesive papillae, while Hroth is expressed in the anterior part of the trunk epidermis. HrHox-1 and Hrcad are expressed in middle and posterior parts of the epidermis, respectively. These data suggested that the epidermis of the ascidian embryo is patterned anteroposteriorly. In ascidian embryogenesis, the epidermis is exclusively derived from animal hemisphere cells. To investigate regulation of expression of the four homeobox genes in the epidermis by vegetal hemisphere cells, we next performed hemisphere isolation and cell ablation experiments. We showed that removal of the vegetal cells before the late 16-cell stage results in loss of expression of these homeobox genes in the animal hemisphere cells. Expression of Hrdll-1 and Hroth depends on contact with the anterior-vegetal (the A-line) cells, while expression of HrHox-1 and Hrcad requires contact with the posterior-vegetal (the B-line) cells. We also demonstrated that contact with the vegetal cells until the late 32-cell stage is sufficient for animal cells to express Hrdll-1, Hroth and Hrcad, while longer contact is necessary for HrHox-1 expression. Contact with the A-line cells until the late 32-cell stage is also sufficient for formation of the adhesive papillae. Our data indicate that the epidermis of the ascidian embryo is patterned along the anteroposterior axis by multiple inductive influences from the vegetal hemisphere cells and provide the first insight into mechanisms of epidermis patterning in the chordate embryos.

Animals↗

PubMed2005

Delivery of germinal granules and localized RNAs via the messenger transport organizer pathway to the vegetal cortex of Xenopus oocytes occurs through directional expansion of the mitochondrial cloud.

During Xenopus oogenesis, the message transport organizer (METRO) pathway delivers germinal granules and localized RNAs to the vegetal cortex of the oocyte via the mitochondrial cloud (Balbiani body). According to the traditional model, the mitochondrial cloud is thought to break up at the onset of vitellogenesis and the germinal granules and METRO-localized RNAs are transported within the mitochondrial cloud fragments to the vegetal cortex of the oocyte. We used light and electron microscopy in situ hybridization and three-dimensional reconstruction to show that germinal granules and METRO-localized RNAs are delivered to the oocyte cortex before the onset of mitochondrial cloud fragmentation and that the delivery involves accumulation of localized RNAs and aggregation of germinal granules at the vegetal tip of the mitochondrial cloud and subsequent internal expansion of the mitochondrial cloud between its animal (nuclear) and vegetal tips, which drives the germinal granules and METRO-localized RNAs toward the vegetal cortex. Thus the fragmentation of the cloud that occurs later in oogenesis is irrelevant to the movement of METRO-localized RNAs and germinal granules. On the basis of these findings, we propose here a revised model of germinal granule and localized RNAs delivery to the oocyte vegetal cortex via the METRO pathway.

Animals↗

PubMed2003

Monitoring change in mountainous dry-heath vegetation at a regional scale using multitemporal Landsat TM data.

Vegetation cover-change analysis requires selection of an appropriate set of variables for measuring and characterizing change. Satellite sensors like Landsat TM offer the advantages of wide spatial coverage while providing land-cover information. This facilitates the monitoring of surface processes. This study discusses change detection in mountainous dry-heath communities in Jämtland County, Sweden, using satellite data. Landsat-5 TM and Landsat-7 ETM+ data from 1984, 1994 and 2000, respectively, were used. Different change detection methods were compared after the images had been radiometrically normalized, georeferenced and corrected for topographic effects. For detection of the classes change--no change the NDVI image differencing method was the most accurate with an overall accuracy of 94% (K = 0.87). Additional change information was extracted from an alternative method called NDVI regression analysis and vegetation change in 3 categories within mountainous dry-heath communities were detected. By applying a fuzzy set thresholding technique the overall accuracy was improved from of 65% (K = 0.45) to 74% (K = 0.59). The methods used generate a change product showing the location of changed areas in sensitive mountainous heath communities, and it also indicates the extent of the change (high, moderate and unchanged vegetation cover decrease). A total of 17% of the dry and extremely dry-heath vegetation within the study area has changed between 1984 and 2000. On average 4% of the studied heath communities have been classified as high change, i.e. have experienced "high vegetation cover decrease" during the period. The results show that the low alpine zone of the southern part of the study area shows the highest amount of "high vegetation cover decrease". The results also show that the main change occurred between 1994 and 2000.

Ecosystem↗

PubMed2003

Distance from roads and cities as a predictor of habitat loss and fragmentation in the caatinga vegetation of Brazil.

Roads and cities represent huge sources of degradation for adjacent ecosystems regarding nutrient cycling, energy, water flow and species composition. In this study we test the hypothesis that distance from roads and cities is associated with habitat loss and fragmentation in the caatinga vegetation--a dry forest to scrub vegetation that covers ca. 736,000 km2 of northeast Brazil. The study site comprised a 2,828.8 km2 piece (64 km x 44.2 km) of Xingó region (09 degrees 36'S, 37 degrees 50'W), which is located between the States of Alagoas and Sergipe. Based on satellite imagery we mapped the remaining vegetation, 145 km of paved roads and the seven small-sized cities set in the study site. A positive correlation was found between the combined distance from roads and cities and the percentage of remaining vegetation as it dropped from 18% at 12 km distant to 5.9% at 1 km distant from cities and roads. Thus, remaining vegetation was reduced by one third near cities and roads. A positive correlation was also found between distance from cities and roads and the percentage of fragments larger than 200 ha, which ranged from 3.6% (within 3 km distance class) to 23.3% (15 km distance class) of all fragments. Our results suggest a road/city-effect zone of 12 to 15 km width, over which habitat loss and fragmentation extend throughout the caatinga vegetation. These findings should be considered in the regional polices for biodiversity conservation and economic development of the caatinga region.

Brazil↗