bluuebunny/crossref_metadata_2025 huggingface dataset:
Microcrustacean communities in streams from two physiographically contrasting regions of Britain
Authors: Rundle Simon D. , Ramsay Paul M.
Published: July 2007

ABSTRACT. Benthic microcrustaceans were sampled from forty‐three streams in two physiographically contrasting regions of Britain: lowland southern England and upland Wales. Lowland streams had a significantly higher species richness than upland streams and, of the forty‐three copepod and cladoceran species identified, only fourteen (33%) were found in both the lowlands and uplands. Canonical correspondence analysis revealed large differences in community structure between regions and between streams within regions. Differences within regions were related to pH, the distance downstream of a site and the presence of upstream impoundments. Variables underlying the large biological differences between regions are also discussed, including differences in chemistry (ionic content), physical parameters (e.g. flow), habitat availability and the influence of species biogeography. The importance of understanding species ecology and biogeography when assessing pollution impacts on stream communities is emphasized and a model is proposed for predicting the composition of microcrustacean communities in temperate European streams.
Genotypic variation in coleus in the ability to accumulate abscisic acid in response to water deficit
Authors: Terry Paul H. , Krizek Donald T. , Mirecki Roman M.
Published: July 2007

Terry, P. H., Krizek, D. T. and Mirecki, R. M. 1988. Genotypic variation in coleus in the ability to accumulate abscisic acid in response to water deficit. ‐ Physiol. Plant. 72: 441–449.

Abscisic acid (ABA) concentration and plant and soil water potentials were determined in leaves of three cultivars of Coleus blumei Benth. cvs. Marty, Buckley Supreme and PI354190, chosen for their differences in sensitivity to drought, SO2 and/or chilling stress. Plants were subjected to ‘gradual’ soil moisture stress (SMS) for 0–6 days, during which time the soil dried out slowly and to more ‘rapid’ SMS for 0–9 days where the soil dried out at a faster rate. Plants were propagated from clonal stock in the greenhouse and transferred to the growth chamber, where they were maintained for 1 week prior to beginning water stress treatment. ABA concentration was determined as the methyl ester using a gas chromatography ‐ electron capture detector method. Samples for ABA determinations were taken from the third pair of leaves from the apex at the same time each day (1430 h). Measurements of stomatal conductance (C5) and leaf water potential (φl) were made on the fourth pair of leaves from the apex, using the same plants as those sampled for ABA. During the more rapid stress portion of the study soil matric potentials (φm) were monitored on a daily basis. Despite large cultivar differences in ABA concentration at 0–6 days, by 7–9 days these differences had largely disappeared. Except for drought‐insensitive cv. Marty, there was generally little correlation between ABA levels and measurements of plant and soil water status at 7–9 days.
Nutrient uptake and allocation at steady‐state nutrition
Authors: Ingestad Torsten , Ågren Göran I.
Published: July 2007

Ingestad, T. and Ågren, G. I. 1988. Nutrient uptake and allocation at steady‐state nutrition. ‐ Physiol. Plant. 72: 450–459.

Net nutrient uptake and translocation rates are discussed for conditions of steady‐state nutrition and growth. Under these conditions, the relative uptake rate is equal to the relative growth rate, for whole plants as well as for plant parts, since the root/shoot ratio and internal concentrations remain stable. The nutrient productivity and the minimum internal concentration are parameters characteristic for the plant and the nutrient. A conceptual, mathematical model, based on these two fundamental parameters is used for calculation and prediction of the net nutrient uptake rate, which is required to maintain steady‐state nutrition at a specified internal nutrient concentration or relative growth rate. When uptake rate is expressed on the basis of the root growth rate, there is, up to optimum, a strong linear relationship between uptake rate and the internal concentration of the limiting nutrient. More complicated and less consistent relationships are obtained when uptake rate is related to root biomass.

The limiting factor for suboptimum uptake is the amount of nutrients becoming available at the root surface. When replenishment is efficient, e.g. with vigorous stirring, the concentration requirement at the root surface appears to be extremely low, even at optimum. In the suboptimum range of nutrition, the effect of nutrient status on root growth rate is a critical factor with a strong feed‐back on nutrition, growth and allocation. At supraoptimum conditions, the uptake mechanism is interpreted as a protection against too high uptake rates and internal concentrations at high external concentration.

In birch (Betula pendulaRoth.), the allocation of nitrogen to the shoots is high compared to that of potassium and also to that of phosphorus at low nitrogen or phosphorus status. With decreasing stress, phosphorus allocation becomes more and more similar to nitrogen allocation. The formulation of a mathematical model for calculation of allocation of biomass and nutrients requires more exact information on the quantitative dependence of the growth‐regulating processes on nutrition.
Reserve mobilization and starch formation in soybean (Glycine max) cotyledons in relation to seedling growth
Authors: Brown Christopher S. , Huber Steven C.
Published: July 2007

Brown, C. S. and Huber, S. C. 1988. Reserve mobilization and starch formation in soybean (Glycine max) cotyledons in relation to seedling growth. ‐ Physiol. Plant. 72: 518–524.

In germinating soybean (Glycine max [L.] Merr.) seedlings, starch accumulated in the cotyledons during the first 5 days of seedling growth. Among 10 genotypes, the amount of starch accumulated after 5 days was relatively independent of light and appeared to be primarily related to the amount of sucrose depleted from the cotyledons during the same time period. Depletion of other reserves (e.g. protein and lipid) were not closely correlated with starch formation. In addition, the differences in starch formation were not related to differences in activities of certain enzymes that may be involved in the conversion of sucrose to starch, namely starch synthase (EC 2.4.1.21), ADP‐glucose pyrophosphorylase (EC 2.7.7.27), sucrose synthase (EC 2.4.1.13), neutral invertase (EC 3.2.1.26), and PPi‐linked phosphofructokinase (PFP) (EC 2.7.1.90). Starch synthesis did not compete with seedling growth, because among 10 genotypes, transient starch formation was correlated positively with seedling growth and cotyledonary photosynthetic rates. We postulate that starch is derived primarily from stored sucrose in the cotyledons and is not merely a result of ‘overflow’ carbon from other reserves. Starch formation also appeared to have a positive relationship with both early (0 to 5 days) and later (5 to 13 days) seedling growth, the latter perhaps due to enhanced cotyledon photosynthetic rates.
The effect of some growth regulators on light‐induced germination of Paulownia tomentosa seeds
Authors: Grubiš;ié D. , Konjevié R. , Neškovié M.
Published: July 2007

Grubišié, D., Konjevié, R. and Neškovié, M. 1988. The effect of some growth regulators on light‐induced germination of Paulownia tomentosa seeds. ‐ Physiol. Plant. 72: 525–528.

The germination of Paulownia tomentosa Steud. (Empress tree) seeds can be induced either by red light (R) or by exogenously applied gibberellic acid (GA3). The R induced germination is completely suppressed by far red irradiation, abscisic acid (ABA) or by growth retardants such as ancymidol, tetcyclacis and paclobutrazol, though not by AMO 1618 or chloro‐choline chloride (CCC). The inhibition caused by far red light (FR) and growth retardants can be overcome by GA3, while the ABA‐induced inhibition can be reversed by fusicoccin (FC), which does not reverse the inhibition caused by FR or growth retardants. It is noteworthy that the germination of light insensitive wheat, corn, alfalfa and mung bean seeds is not inhibited by growth retardants.
Somatic embryogenesis and plant regeneration from suspension cultures of Picea glauca (White spruce)
Authors: Hakman Inger , von Arnold Sara
Published: July 2007

Hakman, I. and von Arnold, S. 1988. Somatic embryogenesis and plant regeneration from suspension cultures of Picea glauca (White spruce). ‐ Physiol. Plant. 72: 579–587.

Plantlets were regenerated from long‐term embryogenic cultures of Picea glauca (Moench) Voss. (White spruce). Embryogenic calli, initiated from immature zygotic embryos and maintained by monthly subculture for 16 months, were used to establish suspension cultures. Small somatic embryos were continuously produced in liquid culture medium containing auxin and cytokinin and the cultures showed a sustained regeneration capacity for >6 months. Somatic embryos propagated in the suspension cultures developed further into embryos bearing cotyledons, about 1 month after transfer to solidified medium containing abscisic acid. Electron microscopic examination revealed that storage nutrients, lipids, proteins and carbohydrates, accumulated in the somatic embryos during this treatment with abscisic acid (ABA). Upon subculture to medium lacking plant growth regulators such embryos could develop into small green plantlets.
Prospects for manipulating the substrate specificity of ribulose bisphosphate carboxylase/oxygenase
Authors: Pierce John
Published: July 2007

Pierce, J. 1988. Prospects for manipulating the substrate specificity of ribulose bisphosphate carboxylase/oxygenase. ‐ Physiol. Plant. 72: 690–698.

The idea of enhancing plant productivity by minimizing the apparently wasteful process of photorespiration has been an enduring one. Since the relative fluxes of carbon through the competing pathways of photosynthesis and photorespiration are determined by the kinetic properties of a single enzyme, ribulose bisphosphate carboxylase/oxygenase, it has been conjectured that genetic modification of this protein could provide more productive plants. Recent advances in techniques for studying ribulose bisphosphate carboxylase/oxygenase hold promise for determining whether such modifications will prove possible.
Suppression of ammonium uptake by nitrogen supply and its relief during nitrogen limitation
Authors: Morgan M. Austin , Jackson William A.
Published: July 2007

Barley (Hordeum vulgare, cv. Triumph), wheat (Triticum aestivum, cv. Kleiber) and oat (Avena sativa, cv. Tarok) were grown until day 20 in nitrate‐containing solutions or in nitrogen‐free solutions for periods up to 8 days immediately prior to day 20. They then were exposed for 4 h to complete, nitrate‐free solutions containing 0.5 or 2.0 mM ammonium (98 atom%15N). In all 3 species in 2 experiments, net ammonium uptake was low in plants grown continuously in nitrate, and increased 3 to 4‐fold with increasing nitrogen deprivation. Charge balance during net ammonium uptake was largely maintained by the sum of net potassium and net proton efflux. Variations in root ammonium concentration at the time of exposure to the ammonium solutions revealed no consistent pattern with net ammonium uptake, implying that a product of ammonium assimilation may serve as a negative effector for the uptake process. In nitrogen‐replete plants, and in those deprived of nitrogen for 2 days, the amounts of endogenous 14N‐ammonium recovered in the ambient 15N‐ammonium solution during the 4‐h uptake period were greater than the initial amounts of 14N‐ammonium present in the root tissue. Significant generation of 14N‐ammonium from endogenous organic nitrogen sources was thus evident in all 3 species.
Photosynthesis and carbon export in white clover plants grown at various levels of phosphorus supply
Authors: Hart A. L. , Greer D. H.
Published: July 2007

Net photosynthesis, concurrent carbon export and starch, sucrose and inorganic phosphorus concentrations were measured in leaves of white clover (Trifolium repens L. cv. Grasslands Huia) grown at four levels of phosphorus supply in the presence or absence of mineral nitrogen. The nitrogen treatments had no effect on growth, photosyntheis or carbon export. At the three higher levels of phosphorus supply, the amount of carbon exported was about 77% of net fixation. Photosynthesis and export per leaf decreased with phosphorus supply, primarily through the effect of phosphorus supply on leaf area. The rate of photosynthesis was reduced only at the lowest level of phosphorus supply.

Inorganic phosphorus rose with phosphorus supply but starch concentration was unaffected. Sucrose was reduced at the lowest level of phosphorus supply but not significantly affected at higher levels. The ratio between starch and sucrose concentration was also unaffected at the higher levels, but was increased at the lowest level of supply. There thus appeared to be direct effects of phosphorus supply on photosynthesis, partitioning of carbon to carbohydrates and, by implication, export, only at the lowest level of phosphorus supply. As leaf area and plant growth were affected over the whole range of phosphorus supply, factors other than photosynthesis per se must have determined the response of growth to phosphorus supply.
Effects of ethylene biosynthesis in carrot root slices on 6‐methoxymellein accumulation and resistance to Botrytis cinerea
Authors: Hoffman Richard , Roebroeck Eugene , Heale James B.
Published: July 2007

The role of ethylene biosynthesis in the resistance response of carrot (Daucus carota L., cv. Chantenay red‐cored) slices to infection by Botrytis cinerea Pers. ex Pers. was investigated using aminoethoxyvinylglycine (AVG) and inhibitor of 1‐aminocyclopropane‐1‐carboxylic acid (ACC) synthase (EC 4.4.1.‐), and norbornadiene, an inhibitor of ethylene binding. Carrot slices became susceptible to a normally non‐invasive level (105 ml‐1) of spores of B. cinerea after treatment with AVG. ACC partially reversed the susceptibility induced by AVG. The ability of a crude pectic enzyme preparation from B. cinerea to induce resistance to a normally invasive level of B. cinerea spores (106 ml‐1) was prevented by AVG. Accumulation of the carrot phyto‐alexin 6‐methoxymellein (6‐MM) was prevented by norbornadiene, but it had no effect on the resistance response. An event associated with ethylene biosynthesis other than 6‐MM accumulation appears to be responsible for the resistance of carrot slices to infection by B. cinerea.
Oxygen limitation of N2 fixation in stem‐girdled and nitrate‐treated soybean
Authors: Vessey J. Kevin , Walsh Kerry B. , Layzell David B.
Published: July 2007

The effects of increasing rhizosphere pO2on nitrogenase activity and nodule resistance to O2diffusion were investigated in soybean plants [Glycine max (L.) Merr. cv. Harosoy 63] in which nitrogenase (EC 1.7.99.2) activities were inhibited by (a) removal of the phloem tissue at the base of the stem (stem girdling), (b) exposure of roots to 10 mM NO3over 5 days (NO3‐treated), or (c) partial inactivation of nitrogenase activity by an exposure of nodulated roots to 100 kPa O2(O2‐inhibitcd).

In control plants and in plants which had been treated with 100 kPa O2, increasing rhizosphere O2concentrations in 10 kPa increments from 20 to 70 kPa did not alter the steady‐state nitrogenase activity. In contrast, in plants in which nitrogenase activities were depressed by stem girdling or by exposure to NO3, increasing rhizosphere pO2resulted in a recovery of 57 or 67%, respectively, of the initial, depressed rates of nitrogenase activity. This suggests that the nitrogenase activity of stem‐girdled and NO3‐treated soybeans was O2‐limited.

For each treatment, theoretical resistance values for O2diffusion into nodules were estimated from measured rates of CO2exchange, assuming a respiratory quotient of 1.1 and 0 kPa of O2in the infected cells. At an external partial pressure of 20 kPa O2, the stem‐girdled and NO3‐‐treated plants displayed resistance values which were 4 to 8.6 times higher than those in the nodules of the control plants. In control and O2‐inhibited plants, increases in pO2from 20 to 70 kPa in 10 kPa increments resulted in a 2.5‐ to 3.9‐fold increase in diffusion resistance to O2, and had little effect on either respiration or nitrogenase activity. In contrast, in stem‐girdled and NO3‐‐treated plants, increases in external pO2had little effect on diffusion resistance to O2, but resulted in a 2.3‐ to 3.2‐fold increase in nodule respiration and nitrogenase activity. These results are consistent with stem‐girdling and NO3‐‐inhibition treatments limiting phloem supply to nodules causing an increase in diffusion resistance to O2at 20 kPa and an apparent insensitivity of diffusion resistance to increases in external pO2.
Induction of vivipary in Avena fatua
Authors: Hsiao A. I. , McIntyre G. I.
Published: July 2007

An investigation was conducted under controlled conditions to determine whether treatments designed to maximize the availability of water during seed development could induce viviparous germination in wild oats (Avena fatua L.). Panicles of three genetic lines, which differed in their degree of dormancy, were kept in darkness at ca 100% RH and 20±1°C and were either supplied with water through the cut end of the rachis or left attached to the plant which was exposed to light. In the non‐dormant line, germination of both primary and secondary caryopses on excised panicles increased with their stage of development when treated, i.e., 0, 5 and 10 days after anthesis. Germination of primary caryopses varied between 70 and 80% and was similar on both isolated and attached panicles treated at 10 and 5 days after anthesis, respectively. The percentage germination was considerably lower in all treatments of the two dormant lines and was inversely related to the genetically determined difference in their degree of dormancy. In these dormant lines germination was significantly lower on the intact plant than on the detached panicles. Water potential measurements suggested that this difference may be due partly to the transpiration‐induced negative ψxyin the stem which may contribute to the inhibition of embryo growth and thus to the prevention of viparous germination.
Impermeant electron acceptors and donors to the plasma membrane‐bound respiratory chain of intact cyanobacterium Anacystis nidulans
Authors: Peschek Günter A. , Kurz Michael A. , Erber Walter W. A.
Published: July 2007

Membrane‐impermeant redox compounds ferricyanide and horse heart ferrocytochrome c acted as electron acceptor and donor, respectively, for intact cells or spheroplasts of Anacystis nidulans (Synechococcus ATCC 27144) in the dark. The anaerobic reduction of ferricyanide was faster than aerobic reduction. KCN significantly enhanced the reaction under aerobic conditions. Light did not influence ferricyanide reduction. The oxidation of exogenous ferrocytochrome c was oxygen‐dependent and inhibited by KCN. Either type of redox reaction was accompanied by vectorial proton translocation out of the cells. Arrhenius plots for the temperature dependence of both ferricyanide reduction and cytochrome c oxidation gave one distinct break point reflecting the lipid phase transition temperature of the plasma membrane. The results are presented as evidence for a respiratory chain in the plasma membrane of A. nidulans.
Zinc‐dependent changes in ESR signals, NADPH oxidase and plasma membrane permeability in cotton roots
Authors: Cakmak Ismail , Marschner Horst
Published: July 2007

The effect of Zn2+on the plasma membrane permeability and superoxide radical (O2‐) formation in roots was studied with cotton (Gossypium hirsutumL. cv. Delta‐pine 15/21) plants grown in nutrient solution with different Zn2+supply. Compared to Zn‐sufficient plants, the plasma membrane permeability of Zn‐deficient plants was increased as indicated by a 3‐, 5‐ and 2.5‐fold increase in root cell leakage of K+, NO3‐and organic carbon compounds, respectively. Resupply of Zn2+to Zn‐deficient plants for 12 h substantially decreased this leakage. The effects of Zn2+on membrane permeability were closely correlated with the levels of O2‐measured by electron spin resonance (ESR) spectroscopy in the microsomal membrane fraction and in the cytosol fraction of root cells. The amplitudes of the O2‐‐derived Tiron ESR signal also coincided with a O2‐‐generating oxidase activity which was strongly dependent on the presence of NADPH and FAD. The results suggest that Zn2+directly affects the integrity of the plasma membrane, at least in part, by interfering with O2‐generation by a membrane‐bound NADPH oxidase.
The effect of inhibitors of plasma membrane redox reactions on proton excretion by plant cells
Authors: Barr Rita
Published: July 2007

Plant cells excrete protons via an electrogenic proton pump, the K+‐stimulated, Mg2+‐dependent H+‐ATPasc, located on the cytoplasmic side of the plasma membrane. Plasma membrane redox reactions are also coupled to proton excretion. Various inhibitors were used on carrot (Daucus carola L.) cells in an attempt to distinguish between the two processes. Inhibitors of electron transport reactions in the plasma membrane (chloroquine, 8‐hydroxyquinolinc, 4,7‐dichloroquinolinc and retinoic acid) inhibited ferricyanide‐induced proton excretion by 37–100%, while they inhibited potassium ferricyanide reduction, a measure of plasma membrane redox activity, by 42–100%. The above‐mentioned quinolines and retinoic acid inhibited cell growth by 49–98%, with the exception of chloroquine, which stimulated carrot cell growth by 36%.
Disputes and courts in Lombard and Carolingian central Italy
Authors: Costambeys Marios
Published: July 2007

This study examines the relationship between judicial courts and the societies in which they operated as revealed by the documents of the abbey of Farfa in the duchy of Spoleto. In a series of case studies it is shown that disputants and judges could draw on a wide range of norms that enabled them to manipulate the settlement process and to tailor it to their own social advantage. Unlike many studies of disputes in central and northern Italy of the early Middle Ages, here weight is given to those aspects of disputing that took place outside the court. It is an approach that casts fresh light on the transition from Lombard to Carolingian rule in central and northern Italy. It also challenges the binary line between the ‘private’ and the ‘public’ in dispute settlement. This, in turn, has implications for how we view the so‐called ‘feudal transformation’ in which the public was supposedly eclipsed by the private.

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Siena in the early Middle Ages: new data from the excavation at Santa Maria della Scala
Authors: Cantini Federico
Published: July 2007

The data from excavations around the hospital of Santa Maria in Siena help to build a picture of the city in the early Middle Ages. Comparison is made with the rural site of Montarrenti, and significant differences between the economic development in the town and country are observed, although both suffered decline. Settlement, and economic activity in the city of Siena are seen to go into recession in the post‐Roman period, but signs of growth become visible from the ninth century onwards.
Alcoholism Effects on Social Migration and Neighborhood Effects on Alcoholism Over the Course of 12 Years
Authors: Buu Anne , Mansour MaryAnn , Wang Jing , Refior Susan K. , Fitzgerald Hiram E. , Zucker Robert A.
Published: July 2007

Background:  Although a short‐term effect of neighborhood characteristics on individual alcohol abuse has been demonstrated by a quasi‐experimental residential mobility study, the obversed effect of alcohol problem involvement on place of residence and residential character has not been studied. We test the alcoholism effect on place of residence, and we also attempt to replicate the neighborhood‐to‐alcoholism effect.

Methods:  A sample of 206 Caucasian men (average age was 33) who were systematically recruited for alcoholism through a court record search of drunk driving offenses and door‐to‐door canvassing, in a 4‐county‐wide area were followed up at 3‐year intervals in a prospective study of the course and outcomes of alcoholism. Participants’ alcoholism diagnoses were made by semistructured diagnostic interviews. Residential addresses at baseline and at 12‐year follow‐up were geocoded. Corresponding census tract variables were used as indicators of neighborhood residential character.

Results:  The regression analysis shows that, the more alcohol problems a man has, the more likely he is going to remain in, or migrate into, a disadvantaged neighborhood. This effect is only evident when a number of relevant confounding variables, including initial level of socioeconomic status, age, antisocial symptomatology, and spousal alcohol‐use disorder status at baseline are controlled. Alcoholics in remission tended to live in neighborhoods whose residential characteristics were not distinguishable from those of nonalcoholics. Unremitted alcoholics, however, tended to stay in or migrate into more disadvantaged neighborhoods.

Conclusion:  Alcoholic involvement has long‐term negative effects on place of residence; involving an elevated likelihood of moving into or remaining in a disadvantaged neighborhood. Recovery from alcoholism is protective against downward social drift on the one hand, and is favorable to improvement in social conditions on the other.
The Performance of the Probability Density Function in Differentiating Supraventricular from Ventricular Rhythms
Authors: TOIVONEN LAURI , VIITASALO MATTI , JÄRVINEN ANTERO
Published: July 2007

TOIVONEN, L., et al.: The Performance of the Probability Density Function in Differentiating Supraventricular from Ventricular Rhythms. The ability of the probability density function (PDF) of an automatic implantable cardioverter defibrillator (AICD) to reject supraventricular arrhythmias being recognized as ventricular was evaluated in 12 patients who were treated with an AICD (Ventak P 1600). The PDF criterion was monitored via telemetry with the sinus rate during exercise test. PDF was satisfied in seven patients at a rate of 75–144/min (mean 109/min), and not in the remaining five patients (mean rate 141/ min). PDF was fulfilled in five of ten patients at a lower heart rate than predicted by the duty cycle index, derived from the ventricular patch lead electrogram at the implantation. Thus PDF is often fulfilled already at a moderately elevated sinus rate. If used to prevent inadvertent AICD discharges during rapid supraventricular rhythms, its performance should be tested in the individual patient.
Demonstration of the Feasibility of Implantation of a Skeletal Muscle Pulse Generator for Fecal Incontinence in a Patient with an Implanted Unipolar DDD Pacemaker
Authors: KONSTEN JOOP , BAETEN COR G.M.I. , DULK KAREL DEN , SPAANS FRANK
Published: July 2007

KONSTEN, J., et al.: Demonstration of the Feasibility of Implantation of a Skeletal Muscle Pulse Genera‐tor for Fecal Incontinence in a Patient with an Implanted Unipolar DDD Pacemaker. Electromagnetic fields and myopotentials from skeletal muscle may interfere with the function of a cardiac pacemaker. A 65‐year‐old woman with a unipolar DDD cardiac pacemaker underwent dynamic graciloplasty (trans‐position of the gracilis muscle around the anal canal and subsequent implantation of a bipolar pulse generator to stimulate the gracilis muscle), for the treatment of fecal incontinence. This gracilis pulse generator is turned “off” with an external magnet to allow defecation. Appropriate functioning of these two pulse generators (the cardiac pacemaker and the gracilis pulse generator) was tested during implantation of the gracilis pulse generator and afterwards. It was demonstrated that the combination could be used safely in this patient.
Assessment of Elastic Properties of the Descending Thoracic Aorta By Transesophageal Echocardiography with Acoustic Quantification in Patients with a Stroke
Authors: Kang Seok‐Min , Ha Jong‐Won , Chung Namsik , Jang Kil‐Jin , Shin Mi‐Seung , Rim Se‐Joong , Cho Seung‐Yun
Published: July 2007

Previous studies have described the use of transesophageal echocardiography (TEE) with acoustic quantification (AQ) in assessing aortic elastic properties. We hypothesized that patients with a prior history of stroke (ST) may have a higher risk of atherosclerotic change in great vessels compared to nonstroke subjects (NST) and thus have decreased elastic properties. We assessed the elastic properties of the descending thoracic aorta (DTA) by TEE in ST patients and compared them with data in NST patients. Subjects included 31 with ST without any evidence of emboli originating from the heart (age 51 ± 10 years, M: F = 20: 11) and 25 age‐matched NST (M: F= 8: 17). Patients with significant valvular heart disease including aortic and mitral regurgitation, left ventricular dysfunction (ejection fraction < 55%), and congenital heart disease were excluded. Compliance (C), distensibility (D), and stiffness index (SI) were measured using AQ and M‐mode measurement at a level of the left atrium. We scored atherosclerotic risk factors (ARF) such as a history of diabetes, hypertension, smoking, hypercholesterolemia, and the presence of atheroma of DTA. There was no evidence of atheroma of DTA in NST. There were no significant differences in heart rate and systolic and diastolic blood pressure between ST and NST patients. Fractional area change (FAC) of DTA was significantly lower in ST than in NST patients (3.2 ± 1.6 vs 5.4 ± 2.5%, P= 0.000). ST patients had significantly lower C (1.2 ± 0.4 vs 1.5 ± 0.7 times 10‐3 cm2 mmHg‐1, P= 0.039), lower D (0.8 ± 0.3 vs 1.5 ± 0.8 times 10‐3 mmHg‐1, P= 0.000), and higher SI (10.3 ± 8.8 vs 5.3 ± 2.9, P= 0.006) than NST patients. ST patients without atheroma of DTA (n± 21) also had significantly lower C (1.1 ± 0.4 vs 1.5 ±0.7 times 10‐3 cm‐2 mmHg‐1, P= 0.038) and lower D (3.5 ± 1.4 vs 4.8 ± 2.4 times 10‐3 mmHg‐1, P= 0.021) than NST patients. There was a significant positive correlation between SI and the score of ARF (r= 0.51, P= 0.000). The regional elastic properties of DTA measured by TEE with AQ and M‐mode method were abnormal in ST. Therefore, TEE with AQ technique may have a possible clinical application for the detection of early atherosclerotic changes such as alteration of elastic properties in morphological normal DTA.
Positional Localization: Three‐Dimensional Transthoracic Echocardiography Techniques for the Measurement of Cardiac Mass, Volume, and Function
Authors: Keller Andrew M.
Published: July 2007

An accurate and reproducible determination of cardiac volume and mass is important for the selection and timing of therapeutic interventions. Quantitative three‐dimensional echocardiography has evolved to provide these measurements with the use of a noninvasive, readily available, and inexpensive technique. We introduce and review the principle of positional localization as well as the clinical application of this technique for the measurement of cardiac volume and mass.
Quantitation of Ventricular Size and Function:
Authors: Mele Donate , Levine Robert A.
Published: July 2007

Two‐dimensional echocardiography is a readily applicable method for the quantification of ventricular volumes. However, it is limited by assumptions regarding ventricular shape. Three‐dimensional echocardiography has emerged as a more accurate and reproducible approach to ventricular volume and functional assessment compared with two‐dimensional echocardiography. We review the principles of transthoracic rotational scanning and its clinical application for quantitative assessment of ventricular volume and function.
Three‐Dimensional Color Doppler Flow Reconstruction and Its Clinical Applications
Authors: Simone Raffaele De , Glombitza Gerald , Vahl Christian Friedrich , Meinzer Hans Peter , Hagl Siegfried
Published: July 2007

The visualization and quantification of intracardiac blood flow have always been a challenging task for the cardiologist. The advent of color Doppler flow imaging substantially enhanced the clinical diagnosis of heart valve disease. Three‐dimensional (3‐D) color Doppler, a new diagnostic procedure, refines the diagnostic value of color Doppler by providing unique spatial and temporal information about the actual extension, direction, origin, and size of intracardiac flows. Here, we describe the procedure for 3‐D color Doppler reconstruction of intracardiac blood flow velocities and reveal the varied findings in different heart pathologies that cause blood flow disturbances. An automated procedure for the segmentation of turbulent and laminar flows, which allows for the measurement of mitral regurgitant jet volumes, is one of the first 3‐D quantitative approaches to the clinical assessment of mitral valve regurgitation. The major technical advances of this procedure include the direct use of digital color Doppler velocity data and an automatic voxel count of the turbulent jet flows. Three‐dimensional color Doppler not only can disclose the spatial complex geometry of intracardiac blood flow disturbances but also can quantitatively assess the severity of mitral valve regurgitation.
Real‐Time Volumetric Echocardiography
Authors: Kisslo Joseph , Firek Bohdan , Ota Takahiro , Kang Duk Hyun , Fleishman Craig E. , Stetten George , Li Jennifer , Ohazama Chikai J. , Adams David , Landolfo Carolyn , Ryan Thomas , von Ramm Olaf
Published: July 2007

The heart is a dynamic organ with complexities in its shape. As such, it places special demands on three‐dimensional techniques for reconstruction. Real‐time volumetric echocardiography, which is based on phased array and parallel processing principles to enhance line density within a scan volume, provides rapid image acquisition. We introduce the principle, potential clinical importance, current limitations, and future of volumetric imaging methods.
mRNA‐Mediated Gene Delivery Into Human Progenitor Cells Promotes Highly Efficient Protein Expression
Authors: Wiehe Juliane M. , Ponsaerts Peter , Rojewski Markus T. , Homann Joerg M. , Greiner Jochen , Kronawitter Desiree , Schrezenmeier Hubert , Hombach Vinzenz , Wiesneth Markus , Zimmermann Oliver , Torzewski Jan
Published: July 2007

Gene transfer into human CD34+ haematopoietic progenitor cells (HPC) and multi‐potent mesenchymal stromal cells (MSC) is an essential tool for numerous in vitro and in vivo applications including therapeutic strategies, such as tissue engineering and gene therapy. Virus based methods may be efficient, but bear risks like tumorigenesis and activation of immune responses. A safer alternative is non‐viral gene transfer, which is considered to be less efficient and accomplished with high cell toxicity. The truncated low affinity nerve growth factor receptor (ÄLNGFR) is a marker gene approved for human in vivo application. Human CD34+ HPC and human MSC were transfected with in vitro‐transcribed mRNA for ΔLNGFR using the method of nucleofection. Transfection efficiency and cell viability were compared to plasmid‐based nucleofection. Protein expression was assessed using flow cytometry over a time period of 10 days. Nucleofection of CD34+ HPC and MSC with mRNA resulted in significantly higher transfection efficiencies compared to plasmid transfection. Cell differentiation assays were performed after selecting ΔLNGFR positive cells using a fluorescent activating cell sorter. Neither cell differentiation of MSC into chondrocytes, adipocytes and osteoblasts, nor differentiation of HPC into burst forming unit erythroid (BFU‐E) colony forming unit‐granulocyte, erythrocyte, macrophage and megakaryocyte (CFU‐GEMM), and CFU‐granulocyte‐macrophage (GM) was reduced. mRNA based nucleofection is a powerful, highly efficient and non‐toxic approach for transient labelling of human progenitor cells or, via transfection of selective proteins, for transient manipulation of stem cell function. It may be useful to transiently manipulate stem cell characteristics and thus combine principles of gene therapy and tissue engineering.
Distinct mechanisms of cardiomyocyte apoptosis induced by doxorubicin and hypoxia converge on mitochondria and are inhibited by Bcl‐xL
Authors: Reeve Janice LV , Szegezdi Eva , Logue Susan E , Chonghaile Tríona Ní , O’Brien Timothy , Ritter Thomas , Samali Afshin
Published: July 2007

Hypoxia and doxorubicin can cause cardiotoxicity and loss of myocardial function. These effects are due, in part, to an induction of apoptosis. Herein we identify the apoptotic pathways activated in H9c2 cells in response to hypoxia (O2/N2/CO2, 0.5:94.5:5) and doxorubicin (0.5 μM). Although the apoptosis induced was accompanied by induction of Fas and Fas ligand, the death receptor pathway was not critical for caspase activation by either stimulus. Hypoxia induced the expression of endoplasmic reticulum (ER) stress mediators and processed ER‐resident pro‐caspase‐12 whereas doxorubicin did not induce an ER stress response. Most importantly, both stimuli converged on mitochondria to promote apoptosis. Accumulation of cytochrome c in the cytosol coincided with the processing of pro‐caspase‐9 and ‐3. Increasing the expression of the anti‐apoptotic protein Bcl‐xL, either by dexamethasone or adenovirus‐mediated transduction, protected H9c2 cells from doxorubicin‐ and hypoxia‐induced apoptosis. Bcl‐xL attenuated mitochondrial cytochrome crelease and reduced downstream pro‐caspase processing and apoptosis. These data demonstrate that two distinct cardiomyocyte‐damaging stimuli converge on mitochondria thus presenting this organelle as a potentially important therapeutic target for anti‐apoptotic strategies for cardiovascular diseases.
Molecular and cellular key players in human islet transplantation
Authors: Hermann M. , Margreiter R. , Hengster P.
Published: July 2007

Introduction

Human islet transplantation

In search of an “endless pool” of β‐cells: embryonic stem cells, adult mesenchymal stem cells, progenitor cells, cell lines and xenotransplantations

•cell proliferation and differentiation

Revascularization of transplanted islets

Will “new” molecules answer “old” questions?

Conclusion

Human islet transplantation could represent an attractive alternative to insulin injections for the treatment of diabetes type 1. However, such an approach requires a better understanding of the molecular and cellular switches controlling β‐cell function in general as well as after transplantation into the liver. Although much research has been done into the suitability of stem or progenitor cells to generate a limitless supply of human β‐cells, a reproducible and efficient protocol for the differentiation of such cells into stably insulin‐secreting β‐cells suitable for transplantation has yet to be reported. Fueled by recent findings showing that mature β‐cells are able to regenerate, many efforts have been undertaken to expand this cell pool. Unfortunately, also these approaches had problems to yield sufficiently differentiated human islet cells. The aim of this review is to summarize recent findings describing some of the molecular and cellular key players of islet biology. A more complete understanding of their orchestration and the use of new methods such as real time confocal imaging for the assessment of islet quality may yield the necessary advancements for more successful human islet transplantation.
Challenges of antiangiogenic cancer therapy: trials and errors, and renewed hope
Authors: Medina Miguel Ángel , Muñoz‐Ch´puli Ramón , Quesada Ana R.
Published: July 2007

Introduction

What can we learn from the previous failures?

Signs of hope

Another turn of the screw: a surrogate marker, at last

Future avenues for the vascular therapy of cancer

Angiogenesis inhibition has been proposed as a general strategy to fight cancer. However, in spite of the promising preclinical results, a first generation of antiangiogenic compounds yielded poor results in clinical trials. Conceptual errors and mistakes in the design of trials and in the definition of clinical end‐points could account for these negative results. In this context of discouraging results, a second generation of antiangiogenic therapies is showing positive results in phases II and III trials at the beginning of the twenty‐first century. In fact, several combined treatments with conventional chemotherapy and antiangiogenic compounds have been recently approved. The discovery and pharmacological development of future generations of angiogenesis inhibitors will benefit from further advances in the understanding of the mechanisms involved in human angiogenesis. New styles of trials are necessary, to avoid missing potential therapeutic effects. Different clinical end‐points, new surrogate biomarkers and methods of imaging will be helpful in this process. Real efficacy in clinical trials may come with the combined use of antiangiogenic agents with conventional chemotherapy or radiotherapy, and combinations of several antiangiogenic compounds with different mechanisms of action. Finally, the existing antiangiogenic strategies should include other approaches such as vascular targeting or angioprevention.
Human placenta: de visu demonstration of interstitial Cajal‐like cells
Authors: Suciu Laura , Popescu L. M. , Gherghiceanu Mihaela
Published: July 2007

Traditional interstitial cells of Cajal (ICC) are present in the digestive tube and are supposed to act as pacemakers and neuromodulators. However, interstitial Cajal‐like cells (ICLCs) were found outside the gastrointestinal tract, in various organs (e.g. ureter, bladder, fallopian tube, uterus, pancreas, mammary gland, myocardium etc.) and looking for such ICLC is a priority in our laboratories.We report here unequivocal visual evidence that ICLCs are present in the mesenchymal tissue of the villi from human term placenta.The following methods were used: a. vital staining with methylene blue (cryosections); b. silver impregnation (paraffin sections); c. Epon‐embedded sections (∼1μm) of glutaraldehyde/osmium fixed tissue, stained with toluidine blue; d. primary cell cultures (or second‐passage cells) to reveal the characteristic, very long, moniliform cell processes and mitochondrial localization at dilations (molecular fluorescence probe: Mito Tracker Green); e. immunofluorescence for c‐kit/CD117 marker or other characteristic proteins; f. transmission electron microscopy to establish the identity of ICLC.
Uncertainty and Medical Authority in the World of Jay Katz
Authors: Burt Robert A.
Published: July 2007

In The Silent World of Doctor and Patient, Jay Katz painted a portrait of medical practice in which physicians voices dominate and drown out others with at least equal and often superior claims to be heard. Many physicians today, however, complain that their voices are no longer sufficiently heard in the provision of medical care. Some are angry at this perceived turn of events; they see intrusions by unscrupulous lawyers, by unsympathetic judges and lay jurors, by greedy malpractice insurance companies and by ham-handed bureaucratic regulators. These angry physicians mimic Rodney Dangerfield's comic complaint that they don't get no respect. And many of these angry physicians regard the influential work of Jay Katz as part of their problem.

Another contemporary group of physicians evaluate Jay's work in a different mood. These physicians, typically younger members of the profession, are intrigued by Jay's analysis and often seem eager to implement it—to solicit patients informed consent, to invite (sensible) judicial or legislative regulation, to eschew the old model of the infallible father-physician.
Disclosure and Consent Problems in Pediatrics
Authors: Holder Angela R.
Published: July 2007

For a symposium in honor of Jay Katz, my teacher, advisor, friend, and ever-present source of help, it is an honor to be asked to write about disclosure and consent in pediatrics. From the time he began to think, write and teach about family law, Jay has advocated taking children and adolescents seriously. In our society such concern for their legal rights is unfortunately rare; the situation would be much worse were it not for Jay's writings and for his former students who have gone on to work for and with children. When he began to work in the areas of human subjects research and then informed consent, his concern for the rights of young people permeated this work as well.
How Litigation Can Promote Product Safety
Authors: Vernick Jon S. , Sapsin Jason W. , Teret Stephen P. , Mair Julie Samia
Published: July 2007

For at least the past three decades, injuries have been recognized as an important public health problem in the United States. In 2001, there were approximately 157,000 deaths due to injuries in the US. There were also almost 30 million non-fatal injury incidents.

Injuries have been defined as: “…any unintentional or intentional damage to the body resulting from acute exposure to thermal, mechanical, electrical, or chemical energy or from the absence of such essentials as heat or oxygen”. Within public health, the field of injury prevention and control is dedicated to reducing the burden of injuries on the lives of people around the world.

Injury prevention seeks to reduce injuries by: 1) identifying risk factors, 2) designing interventions to address the risk factors, 3) implementing those interventions, 4) evaluating their effectiveness, and 5) replicating those that work. As with many other public health problems, interventions can target factors associated with the human or host, vehicle or vector, and the physical or social environment.
Challenging Themes in American Health Information Privacy and the Public’s Health: Historical and Modern Assessments
Authors: Hodge James G. , Gostin Kieran G.
Published: July 2007

Protecting the privacy of individually-identifiable health data is a dominant health policy objective in the new millennium. Technological, economic, and health-related reasons substantiate the development of a national electronic health information infrastructure. Through this emerging infrastructure, billions of pieces of health data of varying sensitivities are exchanged annually to provide health care services and service transactions, conduct health research, and promote the public’s health. These multi-purpose, rapid exchanges of electronic health data, far removed from the typical disclosure of health information through the doctor/patient relationship of yesteryear, contribute to heightened individual concerns about identifiable health data. Responding to American fears and perceptions of actual and potential privacy abuses, policymakers have recently developed new, modern privacy protections through legislative and regulatory laws, as well as ethical and industry codes.

Modern health information privacy protections are reflected in federal regulations developed by the federal Department of Health and Human Services (DHHS) pursuant to the Health Insurance Portability and Accountability Act of 1996 (HIPAA).
The ELSI Genetics Regulatory Resource Kit: A Tool for Policymakers in Developing Countries
Authors: Merali Zara , Singer Peter A. , Boulyjenkov Victor , Daar Abdallah S.
Published: July 2007

The international context of the last fifty years of modern bioethics have been significant in establishing health-care ethics or bioethics as a common parlance - an ideology of our times, achieving near universal acceptance, with little dissent. Most international health organizations have developed important declarations that have become the credo of their daily practice and long-term commitments. However, in the last decade in particular, bioethicists and other health-care practitioners and scholars have worried about the persistence of health-care inequities and the inadequate realization of bioethics, particularly in low-to-middle income countries. Global bioethics, now well into the new millennium, has entered a regulatory crisis: it needs to confront not just global bioethical commitments around major scientific revolutions such as genomics, but further, a regulatory crisis about the persisting national public law silences and health inequities, especially in low-to-middle income countries.