Finite indentation of highly curved elastic shells.

Experimentally measuring the elastic properties of thin biological surfaces is non-trivial, particularly when they are curved. One technique that may be used is the indentation of a thin sheet of material by a rigid indenter, while measuring the applied force and displacement. This gives immediate information on the fracture strength of the material (from the force required to puncture), but it is also theoretically possible to determine the elastic properties by comparing the resulting force-displacement curves with a mathematical model. Existing mathematical studies generally assume that the elastic surface is initially flat, which is often not the case for biological membranes. We previously outlined a theory for the indentation of curved isotropic, incompressible, hyperelastic membranes (with no bending stiffness) which breaks down for highly curved surfaces, as the entire membrane becomes wrinkled. Here, we introduce the effect of bending stiffness, ensuring that energy is required to change the shell shape without stretching, and find that commonly neglected terms in the shell equilibrium equation must be included. The theory presented here allows for the estimation of shape- and size-independent elastic properties of highly curved surfaces via indentation experiments, and is particularly relevant for biological surfaces.

16S rRNA gene sequencing on a benchtop sequencer: accuracy for identification of clinically important bacteria.

AIMS: Test the choice of 16S rRNA gene amplicon and data analysis method on the accuracy of identification of clinically important bacteria utilizing a benchtop sequencer. METHODS AND RESULTS: Nine 16S rRNA amplicons were tested on an Ion Torrent PGM to identify 41 strains of clinical importance. The V1-V2 region identified 40 of 41 isolates to the species level. Three data analysis methods were tested, finding that the Ribosomal Database Project's SequenceMatch outperformed BLAST and the Ion Reporter Metagenomics analysis pipeline. Lastly, 16S rRNA gene sequencing mixtures of four species through a six log range of dilution showed species were identifiable even when present as 0·1% of the mixture. CONCLUSIONS: Sequencing the V1-V2 16S rRNA gene region, made possible by the increased read length Ion Torrent PGM sequencer's 400 base pair chemistry, may be a better choice over other commonly used regions for identifying clinically important bacteria. In addition, the SequenceMatch algorithm, freely available from the Ribosomal Database Project, is a good choice for matching filtered reads to organisms. Lastly, 16S rRNA gene sequencing's sensitivity to the presence of a bacterial species at 0·1% of a mixture suggests it has sufficient sensitivity for samples in which important bacteria may be rare. SIGNIFICANCE AND IMPACT OF THE STUDY: We have validated 16S rRNA gene sequencing on a benchtop sequencer including simple mixtures of organisms; however, our results highlight deficits for clinical application in place of current identification methods.

Gene-directed enzyme prodrug therapy for localized chemotherapeutics in allograft and xenograft tumor models.

Most chemotherapy regimens rely on systemic administration of drugs leading to a wide array of toxicities. Using viral-vector-mediated gene modification of muscle tissues, we have developed a method for gene-directed enzyme prodrug therapy that allows for localized drug administration. An inactive prodrug of geldanamycin was activated locally for inhibition of tumor growth without systemic toxicities. A recombinant adeno-associated virus (rAAV) was used to deliver ß-galactosidase (LacZ) to the treatment group and green fluorescent protein to the control group. After 1 week, both groups received adenocarcinoma cells in the same location as the previous rAAV injection. The geldanamycin prodrug was administered 1 h later via intraperitoneal injection. Tumor growth was significantly suppressed in animals whose muscles were gene modified to express ß-galactosidase compared with the control. Serum assay to access hepatotoxicity resulted in no significant differences between the animals treated with the inactive or activated form of geldanamycin, indicating minimal damage to non-target organs. Using gene-directed enzyme prodrug therapy, in combination with novel recombinant AAV vectors, we have developed a method for localized activation of chemotherapeutic agents that limits the toxicities seen with traditional systemic administration of these potent drugs.

7 Tesla (T) human cardiovascular magnetic resonance imaging using FLASH and SSFP to assess cardiac function: validation against 1.5 T and 3 T.

We report the first comparison of cardiovascular magnetic resonance imaging (CMR) at 1.5 T, 3 T and 7 T field strengths using steady state free precession (SSFP) and fast low angle shot (FLASH) cine sequences. Cardiac volumes and mass measurements were assessed for feasibility, reproducibility and validity at each given field strength using FLASH and SSFP sequences. Ten healthy volunteers underwent retrospectively electrocardiogram (ECG) gated CMR at 1.5 T, 3 T and 7 T using FLASH and SSFP sequences. B1 and B0 shimming and frequency scouts were used to optimise image quality. Cardiac volume and mass measurements were not significantly affected by field strength when using the same imaging sequence (P > 0.05 for all parameters at 1.5 T, 3 T and 7 T). SSFP imaging returned larger end diastolic and end systolic volumes and smaller left ventricular masses than FLASH imaging at 7 T, and at the lower field strengths (P < 0.05 for each parameter). However, univariate general linear model analysis with fixed effects for sequence and field strengths found an interaction between imaging sequence and field strength (P = 0.03), with a smaller difference in volumes and mass measurements between SSFP and FLASH imaging at 7 T than 1.5 T and 3 T. SSFP and FLASH cine imaging at 7 T is technically feasible and provides valid assessment of cardiac volumes and mass compared with CMR imaging at 1.5 T and 3 T field strengths.

Comparison between eight- and sixteen-channel TEM transceive arrays for body imaging at 7 T.

Eight- and sixteen-channel transceive stripline/TEM body arrays were compared at 7 T (297 MHz) both in simulation and experiment. Despite previous demonstrations of similar arrays for use in body applications, a quantitative comparison of the two configurations has not been undertaken to date. Results were obtained on a male pelvis for assessing transmit, signal to noise ratio, and parallel imaging performance and to evaluate local power deposition versus transmit B(1) (B(1) (+) ). All measurements and simulations were conducted after performing local B(1) (+) phase shimming in the region of the prostate. Despite the additional challenges of decoupling immediately adjacent coils, the sixteen-channel array demonstrated improved or nearly equivalent performance to the eight-channel array based on the evaluation criteria. Experimentally, transmit performance and signal to noise ratio were 22% higher for the sixteen-channel array while significantly increased reduction factors were achievable in the left-right direction for parallel imaging. Finite difference time domain simulations demonstrated similar results with respect to transmit and parallel imaging performance, however, a higher transmit efficiency advantage of 33% was predicted. Simulations at both 3 and 7 T verified the expected parallel imaging improvements with increasing field strength and showed that, for a specific B(1) (+) shimming strategy used, the sixteen-channel array exhibited lower local and global specific absorption rate for a given B(1) (+) .

Initial results of cardiac imaging at 7 Tesla.

This work reports preliminary results from the first human cardiac imaging at 7 Tesla (T). Images were acquired using an eight-channel transmission line (TEM) array together with local B(1) shimming. The TEM array consisted of anterior and posterior plates closely positioned to the subjects' thorax. The currents in the independent elements of these arrays were phased to promote constructive interference of the complex, short wavelength radio frequency field over the entire heart. Anatomic and functional images were acquired within a single breath hold to reduce respiratory motion artifacts while a vector cardiogram (VCG) was used to mitigate cardiac motion artifacts and gating. SAR exposure was modeled, monitored, and was limited to FDA guidelines for the human torso in subject studies. Preliminary results including short-axis and four-chamber VCG-retrogated FLASH cines, as well as, short-axis TSE images demonstrate the feasibility of safe and accurate human cardiac imaging at 7T.

Leukotrienes in patients with clinically active multiple sclerosis.

OBJECTIVES: The role of leukotrienes (LTs) in the pathophysiology of multiple sclerosis (MS) has been controversially discussed in the past. Studies of LTs in the cerebrospinal fluid (CSF) revealed different results mainly because of analytical difficulties. MATERIAL AND METHODS: In the present study we used highly sensitive and specific analytical methods for measuring LTs in the CSF as well as in urine samples from 20 patients with active MS and 20 control patients with noninflammatory neurological disorders. RESULTS: LTB4 concentrations in CSF were almost twice as high in MS patients compared with controls (P < 0.001). CSF concentrations of the cysteinyl-LTs (LTC4, LTD4 and LTE4) as well as urinary LTE4 showed no significant differences compared with controls (P > 0.05). In addition, there was no significant association between CSF pleocytosis, clinical severity or time of disease onset. CONCLUSIONS: The increased concentration of LTB4 in the CSF of MS patients may indicate a biological importance for this mediator in MS.

Brassinosteroids and gibberellins promote tobacco seed germination by distinct pathways.

Seed germination of Nicotiana tabacum L. cv. Havana 425 is determined by the balance of forces between the growth potential of the embryo and the mechanical restraint of the micropylar endosperm. In contrast to the gibberellin GA4, the brassinosteroid (BR) brassinolide (BL) did not release photodormancy of dark-imbibed photodormant seeds. Brassinolide promoted seedling elongation and germination of non-photodormant seeds, but did not appreciably affect the induction of class I beta-1,3-glucanase (betaGLU I) in the micropylar endosperm. Brassinolide, but not GA4, accelerated endosperm rupture of tobacco seeds imbibed in the light. Brassinolide and GA4 promoted endosperm rupture of dark-imbibed non-photodormant seeds, but only GA4 enhanced betaGLU I induction. Promotion of endosperm rupture by BL was dose-dependent and 0.01 microM BL was most effective. Brassinolide and GA4 promoted abscisic acid (ABA)-inhibited dark-germination of non-photodormant seeds, but only GA4 replaced light in inducing betaGLU I. These results indicate that BRs and GAs promote tobacco seed germination by distinct signal transduction pathways and distinct mechanisms. Gibberellins and light seem to act in a common pathway to release photodormancy, whereas BRs do not release photodormancy. Induction of betaGLU I in the micropylar endosperm and promotion of release of 'coat-enhanced' dormancy seem to be associated with the GA-dependent pathway, but not with BR signalling. It is proposed that BRs promote seed germination by directly enhancing the growth potential of the emerging embryo in a GA- and betaGLU I-independent manner.

Antisense-transformation reveals novel roles for class I beta-1,3-glucanase in tobacco seed after-ripening and photodormancy.

Little is known about the molecular basis for seed dormancy, after-ripening, and radicle emergence through the covering layers during germination. In tobacco, endosperm rupture occurs after testa rupture and is the limiting step in seed germination. Class I beta-1,3-glucanase (betaGLU I), which is induced in the micropylar endosperm just prior to its penetration by the radicle, is believed to help weaken the endosperm wall. Evidence is presented here for a second site of betaGLU I action during after-ripening. Tobacco plants were transformed with antisense betaGLU I constructs with promoters thought to direct endosperm-specific expression. Unexpectedly, these transformants were unaffected in endosperm rupture and did not exhibit reduced betaGLU I expression during germination. Nevertheless, antisense betaGLU I transformation delayed the onset of testa rupture in light-imbibed, after-ripened seeds and inhibited the after-ripening-mediated release of photodormancy. It is proposed that betaGLU I expression in the dry seed contributes to the after-ripening-mediated release of seed dormancy.

Class I beta-1,3-glucanase and chitinase are expressed in the micropylar endosperm of tomato seeds prior to radicle emergence.

beta-1,3-Glucanase (EC 3.2.1.39) and chitinase (EC 3.2.1.14) mRNAs, proteins, and enzyme activities were expressed specifically in the micropylar tissues of imbibed tomato (Lycopersicon esculentum Mill.) seeds prior to radicle emergence. RNA hybridization and immunoblotting demonstrated that both enzymes were class I basic isoforms. beta-1,3-Glucanase was expressed exclusively in the endosperm cap tissue, whereas chitinase localized to both endosperm cap and radicle tip tissues. beta-1,3-Glucanase and chitinase appeared in the micropylar tissues of gibberellin-deficient gib-1 tomato seeds only when supplied with gibberellin. Accumulation of beta-1,3-glucanase mRNA, protein and enzyme activity was reduced by 100 microM abscisic acid, which delayed or prevented radicle emergence but not endosperm cap weakening. In contrast, expression of chitinase mRNA, protein, and enzyme activity was not affected by abscisic acid. Neither of these enzymes significantly hydrolyzed isolated tomato endosperm cap cell walls. Although both beta-1,3-glucanase and chitinase were expressed in tomato endosperm cap tissue prior to radicle emergence, we found no evidence that they were directly involved in cell wall modification or tissue weakening. Possible functions of these hydrolases during tomato seed germination are discussed.

MRI vs. histologic measurement of breast cancer following chemotherapy: comparison with x-ray mammography and palpation.

Twenty consecutive patients with breast cancer were evaluated following chemotherapy using MRI to assess the size of cancer residua and compare these data with subsequent histologic measurements of the viable tumor. This retrospective study also involved assessment of the preoperative size of the malignancy as determined by physical exam and x-ray mammogram. These values were later compared with the histology. The tumor size correlation coefficient between MRI and pathologic analysis was the highest, at 0.93. Physical exam and x-ray mammography (available for 17 patients) produced correlation coefficients of 0.72 and 0.63, respectively, compared to histologic measurement. The accuracy of MRI did not vary with the size of cancer residua. MRI is an accurate method for preoperative assessment of breast cancer residua following chemotherapy. J. Magn. Reson. Imaging 2001;13:868-875.

Cytotoxic synergism of methioninase in combination with 5-fluorouracil and folinic acid.

Potentiation of the cytotoxic activity of 5-fluorouracil (FUra) by folinic acid (5-HCO-H4folate) is due to elevation of the methylene tetrahydrofolate (CH2-H4folate) level, which increases the stability of the ternary complex of thymidylate synthase (TS), fluorodeoxyuridine monophosphate, and CH2-H4folate that inactivates the TS. Methionine deprivation results in the production of tetrahydrofolate (H4folate) and, subsequently, CH2-H4folate from methyl tetrahydrofolate, as a consequence of the induction of methionine synthesis. We hypothesized that the efficacy of FUra could be augmented by the combination of high-concentration 5-HCO-H4folate and recombinant methioninase (rMETase), a methionine-cleaving enzyme. Studies in vitro were performed with the cell line CCRF-CEM. Cytotoxic synergism of FUra + rMETase and FUra + 5-HCO-H4folate + rMETase was demonstrated with the combination index throughout a broad concentration range of FUra and rMETase. A subcytotoxic concentration of rMETase reduced the IC50 of FUra by a factor of 3.6, and by a factor of 7.5, in the absence and in the presence of 5-HCO-H4folate, respectively. 5-HCO-H4folate increased the intracellular concentrations of CH2-H4folate and H4folate from their baseline levels. Concentrations of folates were not changed by exposure to rMETase. Levels of free TS in cells treated with FUra + 5-HCO-H4folate and with FUra + rMETase were lower than those in cells exposed to FUra alone. The decrease of TS was still more pronounced in cells treated with FUra + 5-HCO-H4folate + rMETase. The synergism described in this study will be a basis for further exploration of combinations of fluoropyrimidines, folates, and rMETase.

Beta-1, 3-glucanase and chitinase transgenes in hybrids show distinctive and independent patterns of posttranscriptional gene silencing.

Nicotiana sylvestris Speg. & Comes transformed with a tobacco class-I beta-1,3-glucanase (GLU I ) cDNA driven by CaMV 35S RNA expression signals exhibits posttranscriptional gene silencing (PTGS) which is triggered between the cotyledon and two-leaf stages of seedling development and is postmeiotically reset to the high-expressing state during seed development. The incidence of GLU I PTGS in sibling plants differed for the two different transformants tested and increased with the number of T-DNA loci. Comparison of host class-I and class-II beta-1,3-glucanase gene expression suggests that a similarity of 60-70% in the coding-region is required for PTGS of the homologous host genes. The GLU I transformants exhibited a spatial gradient in PTGS, in which expression of the silent phenotype gradually increased in successive leaves toward the bottom of the plant. In contrast, transformants carrying an unrelated tobacco class I chitinase (CHN I) cDNA in the same expression vector exhibited discontinuous patterns of PTGS with adjacent high-expressing and silent leaves. The GLU I- and CHN I-specific patterns were maintained in hybrids homozygous for both T-DNA's indicating that two different transgenes present in the same genome can exhibit independent and distinctive patterns of PTGS. This implies that the nature of the transgene rather than a general pre-pattern of competence for PTGS or propagation of the silent state are important for pattern determination.

Sense transformation reveals a novel role for class I beta-1, 3-glucanase in tobacco seed germination.

'Coat-enhanced' seed dormancy of many dicotyledonous species, including tobacco, is released during after-ripening. Rupture of the endosperm, which is the limiting step in tobacco seed germination, is preceded by induction of class I beta-1,3-glucanase (betaGLU I) in the micropylar endosperm where the radicle will penetrate. Treating after-ripened tobacco seeds with abscisic acid (ABA) delays endosperm rupture and inhibits betaGLU I induction. Sense transformation with a chimeric ABA-inducible betaGLU I transgene resulted in over-expression of betaGLU I in seeds and promoted endosperm rupture of mature seeds and of ABA-treated after-ripened seeds. Taken together, these results provide direct evidence that betaGLU I contributes to endosperm rupture. Over-expression of betaGLU I during germination also replaced the effects of after-ripening on endosperm rupture. This suggests that regulation of betaGLU I by ABA signalling pathways might have a key role in after-ripening.

Ethylene promotes ethylene biosynthesis during pea seed germination by positive feedback regulation of 1-aminocyclo-propane-1-carboxylic acid oxidase.

Increased ethylene evolution accompanies seed germination of many species including Pisum sativum L., but only a little is known about the regulation of the ethylene biosynthetic pathway in different seed tissues. Biosynthesis of the direct ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), the expression of ACC oxidase (ACO), and ethylene production were investigated in the cotyledons and embryonic axis of germinating pea seeds. An early onset and sequential induction of ACC biosynthesis, accumulation of Ps-ACO1 mRNA and of ACO activity, and ethylene production were localized almost exclusively in the embryonic axis. Maximal levels of ACC, Ps-ACO1 mRNA, ACO enzyme activity and ethylene evolution were found when radicle emergence was just complete. Treatment of germinating seeds with ethylene alone or in combination with the inhibitor of ethylene action 2,5-norbornadiene showed that endogenous ethylene regulates its own biosynthesis through a positive feedback loop that enhances ACO expression. Accumulation of Ps-ACO1 mRNA and of ACO enzyme activity in the embryonic axis during the late phase of germination required ethylene, whereas Ps-ACS1 mRNA levels and overall ACC contents were not induced by ethylene treatment. Ethylene did not induce ACO in the embryonic axis during the early phase of germination. Ethylene-independent signalling pathways regulate the spatial and temporal pattern of ethylene biosynthesis, whereas the ethylene signalling pathway regulates high-level ACO expression in the embryonic axis, and thereby enhances ethylene evolution during seed germination.

Relationship of atypical melatonin rhythm with two circadian clock outputs in B6D2F(1) mice.

Circadian rhythms in body temperature, locomotor activity, and the circadian changes of plasma and pineal melatonin content were investigated in B6D2F(1) mice synchronized by 12 h of light and 12 h of darkness. During 8 wk continuous recording, activity and temperature displayed a marked stable and reproducible circadian rhythm, with both peaks occurring near the middle of darkness. Both 24- and 12-h rhythmic components were also significantly detected. Mean plasma melatonin concentration rose steadily during the light span and reached a maximum (30.6 +/- 10.0 pg/ml) at 11 h after light onset (HALO), then gradually decreased after the onset of darkness to a nadir (4.7 +/- 0.4 pg/ml) at 20 HALO. Mean pineal content followed a pattern parallel to that of plasma concentration (peak at 11 HALO: 17.7 +/- 1.0 pg/gland; trough at 17 HALO: 4.7 +/- 1.0 pg/gland). In addition, a second sharp peak was observed at 21 HALO (20.2 +/- 3.5 pg/gland). Plasma and pineal contents displayed large and statistically significant circadian changes, with a composite rhythm of period (24 + 12 h). This mouse model has predominant production and secretion of melatonin during the day. This possibly contributes to a similar coupling between chronopharmacology mechanisms and the rest-activity cycle in these mice and in human subjects.

Oxaliplatin: pharmacokinetics and chronopharmacological aspects.

Oxaliplatin is the first clinically available diaminocyclohexane platinum coordination complex. The drug is non-cross-resistant with cisplatin or carboplatin and is one of the few active drugs against human colorectal cancer. Its cytotoxicity is synergistic with fluorouracil and folinic acid (leucovorin), the reference treatment for this disease. The main cumulative dose-limiting toxicity of oxaliplatin is peripheral sensory neuropathy. The drug can also produce diarrhoea, vomiting and haematological suppression. Unlike cisplatin, no renal failure or peripheral motor neuropathy have been reported and the sensory neuropathy is partly reversible. Unlike carboplatin, oxaliplatin produces only mild to moderate haematological toxicity. Oxaliplatin undergoes biotransformation into aquated forms in the blood, where 3 species can be found: total platinum, ultrafilterable or 'free' platinum and erythrocyte platinum. Flameless atomic absorption (FAAS) is used for assaying platinum concentration in various tissues. Inductively-coupled plasma mass spectrometry (ICP-MS), with a >10-fold lower sensitivity threshold than FAAS, was also used for the determination of oxaliplatin pharmacokinetics. The pharmacokinetics of oxaliplatin are described by a 3-compartment model. The drug rapidly crosses the cellular membrane as a result of its lipophilicity. Hence, at the end of a 2-hour infusion, approximately 40% of the blood platinum is found in erythrocytes. The distribution half-life of ultrafiltrated plasma platinum ranges from 10 to 25 minutes and its terminal elimination half-life is 26 hours (determined with FAAS) or 270 hours (ICP-MS). The elimination half-life of erythrocytic platinum is 12 to 50 days, close to that of erythrocytes. 30 to 50% of the platinum is recovered in the urine within 2 to 5 days, with renal clearance accounting for half of the total clearance of ultrafiltrated platinum. The total clearance of this species is correlated with the glomerular filtration rate. No pharmacokinetic-pharmacodynamic relationship has been established for oxaliplatin. Pharmacokinetic alterations produced by fluorouracil + folinic acid or irinotecan were minimal if any. The prolonged stability of oxaliplatin makes it suitable for continuous infusions over 4 to 5 days, with a delivery rate which can be either constant or chronomodulated (peak rate at 1600h), using programmable ambulatory pumps. Chronomodulation significantly reduces toxicity and improves antitumour activity as compared with constant rate infusion. These differences in pharmacodynamic properties were paralleled by differences in plasma concentration time courses. The different drug concentration profiles achieved with different infusional modalities may be useful tools for understanding the relationship between the pharmacokinetics and pharmacodynamics of oxaliplatin and may lead to further optimisation of its administration schedule and its combination with other drugs.

[Interventions in carotid stenoses: carotid srugery, percutaneous transluminal balloon angioplasty and stent implantation. Indications, results of clinical studies. An overview]. / Interventionen an Carotisstenosen: Carotischirurgie, perkutane transluminale Ballonangioplastie und Stentimplantation. Indikationsstellung, Ergebnisse klinischer Studien. Eine Ubersicht.

Ischemic stroke is the third most reason of death and the main reason of severe disability in Western countries. The high incidence of stroke, 330 per 100,000 subjects in Germany, illustrates the importance of the disease. Generally, atherosclerotic stenosis of the proximal internal carotid artery is the responsible mechanism. The clinical efficiency of surgically performed endarterectomy has been demonstrated in several large multicenter trials. Proven indications for endarterectomy are symptomatic moderate to high-grade stenoses, rapidly progressive asymptomatic stenoses and asymptomatic patients with lesions revealing greater than sixty percent diameter stenosis under certain clinical conditions. Reduction of the incidence of cerebrovascular events, though, is only possible if a low perioperative complication rate is accomplished. Recommendations of the American Heart Association demand a total periprocedural complication rate less than six percent for symptomatic and less than three percent for asymptomatic stenoses. Implantation of stents in carotid arteries is a promising method which might expand the spectrum of indications toward stenosis morphology unfavorable for surgery and patients with significant comorbidity. Clinical results reveal primary success rates, complication rates, and restenosis rates comparable with those of surgical endarterectomy. Randomized trials, comparing both methods, are necessary and reasonable. Yet results are not available at the moment.

Distinct ethylene- and tissue-specific regulation of beta-1,3-glucanases and chitinases during pea seed germination.

The expression of beta-1,3-glucanase (betaGlu) and chitinase (Chn) was investigated in the testa, cotyledons, and embryonic axis of germinating Pisum sativum L. cv. 'Espresso generoso' seeds. High concentrations of betaGlu and Chn activity were found in the embryonic axis. Treatment with ethylene alone or in combination with the inhibitor of ethylene action 2,5-norbornadiene showed that an early, 4-fold induction of betaGlu activity in the embryonic axis during the first 20 h after the start of imbibition is ethylene-independent. This initial increase was followed by a later 4-fold ethylene-dependent induction in the embryonic axis starting at 50 h, which is after the onset of ethylene evolution and after completion of radicle emergence. The betaGlu activity in cotyledons increased gradually throughout germination and was ethylene-independent. In contrast, the ethylene-independent Chn activity increased slightly after the onset of radical emergence in the embryonic axis and remained at a constant low level in cotyledons. Immunoinactivation assays and immunoblot analyses suggest that early betaGlu activity in the embryonic axis is due to a 54-kDa antigen, whereas late induction is due to a 34.5-kDa antigen, which is likely to be the ethylene-inducible class I betaGlu G2 described for immature pea pods. Increases in Chn in the embryonic axis were correlated with a 26-kDa antigen, whereas amounts of the additional 32- and 20-kDa antigens remained roughly constant. Thus, ethylene-dependent and ethylene-independent pathways regulate betaGlu and Chn during pea seed germination. The pattern of regulation differs from that of leaves and immature pods, and from that described for germinating tobacco seeds. The functional significance of this regulation and its underlying mechanisms are discussed.

[Calcifying aortic valve stenosis and occult gastrointestinal hemorrhage (Heyde syndrome): description of 2 cases]. / Kalzifizierende Aortenklappenstenose und okkulte gastrointestinale Blutung (Heyde-Syndrom): Beschreibung zweier Kasuistiken.

The coincidence of aortic valve stenosis and cryptogenic gastrointestinal bleeding usually from angiodysplasia of the cecum and ascending colon has been called Heyde syndrome. The pathophysiologic link between both remains unclear and may be due to subtle changes in plasmatic coagulation. There are some statistic and numerous casuistic reports, and recently the existence of the syndrome has been questioned. We describe two cases of aortic valve stenosis and cryogenic gastrointestinal bleeding in which bleeding subsided after replacement with a bioprosthesis. We give an overview of the current literature.