55 Fruit St Pediatric Surgery Wrn 11
Boston MA 02114
Medical School: Dartmouth Medical School - 1987
Accepts Medicare: Yes
Participates In eRX: Yes
Participates In PQRS: Yes
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License #: 74011
Taxonomy Codes:208600000X 2086S0120X
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Transient Coma Due To Epidural Anesthesia: The Role of Loss of Sensory Input. - The American journal of case reports
BACKGROUND Epidural anesthesia is the most commonly used method of pain relief during labor in the USA. It is not classically associated with alterations in level of alertness. Coma during the procedure is rare, with a reported incidence of 0.1-0.3%. CASE REPORT An otherwise healthy patient experienced almost complete loss of brainstem function following routine epidural anesthesia during delivery. The episode lasted for less than 3 hours and the patient made a full recovery. To our knowledge, this is the most detailed clinical observation to date of this condition. CONCLUSIONS Clinicians should be aware of this rare and potentially serious complication of epidural anesthesia. The case highlights the need for sensory input to maintain alertness through the activity of the ascending reticular activating system.
Systems responses to progressive water stress in durum wheat. - PloS one
Durum wheat is susceptible to terminal drought which can greatly decrease grain yield. Breeding to improve crop yield is hampered by inadequate knowledge of how the physiological and metabolic changes caused by drought are related to gene expression. To gain better insight into mechanisms defining resistance to water stress we studied the physiological and transcriptome responses of three durum breeding lines varying for yield stability under drought. Parents of a mapping population (Lahn x Cham1) and a recombinant inbred line (RIL2219) showed lowered flag leaf relative water content, water potential and photosynthesis when subjected to controlled water stress time transient experiments over a six-day period. RIL2219 lost less water and showed constitutively higher stomatal conductance, photosynthesis, transpiration, abscisic acid content and enhanced osmotic adjustment at equivalent leaf water compared to parents, thus defining a physiological strategy for high yield stability under water stress. Parallel analysis of the flag leaf transcriptome under stress uncovered global trends of early changes in regulatory pathways, reconfiguration of primary and secondary metabolism and lowered expression of transcripts in photosynthesis in all three lines. Differences in the number of genes, magnitude and profile of their expression response were also established amongst the lines with a high number belonging to regulatory pathways. In addition, we documented a large number of genes showing constitutive differences in leaf transcript expression between the genotypes at control non-stress conditions. Principal Coordinates Analysis uncovered a high level of structure in the transcriptome response to water stress in each wheat line suggesting genome-wide co-ordination of transcription. Utilising a systems-based approach of analysing the integrated wheat's response to water stress, in terms of biological robustness theory, the findings suggest that each durum line transcriptome responded to water stress in a genome-specific manner which contributes to an overall different strategy of resistance to water stress.
Source/sink interactions underpin crop yield: the case for trehalose 6-phosphate/SnRK1 in improvement of wheat. - Frontiers in plant science
Considerable interest has been evoked by the analysis of the regulatory pathway in carbohydrate metabolism and cell growth involving the non-reducing disaccharide trehalose (TRE). TRE is at small concentrations in mesophytes such as Arabidopsis thaliana and Triticum aestivum, excluding a role in osmoregulation once suggested for it. Studies of TRE metabolism, and genetic modification of it, have shown a very wide and more important role of the pathway in regulation of many processes in development, growth, and photosynthesis. It has now been established that rather than TRE, it is trehalose 6-phosphate (T6P) which has such profound effects. T6P is the intermediary in TRE synthesis formed from glucose-6-phosphate and UDP-glucose, derived from sucrose, by the action of trehalose phosphate synthase. The concentration of T6P is determined both by the rate of synthesis, which depends on the sucrose concentration, and also by the rate of breakdown by trehalose-6-phosphate phosphatase which produces TRE. Changing T6P concentrations by genetically modifying the enzymes of synthesis and breakdown has altered photosynthesis, sugar metabolism, growth, and development which affect responses to, and recovery from, environmental factors. Many of the effects of T6P on metabolism and growth occur via the interaction of T6P with the SnRK1 protein kinase system. T6P inhibits the activity of SnRK1, which de-represses genes encoding proteins involved in anabolism. Consequently, a large concentration of sucrose increases T6P and thereby inhibits SnRK1, so stimulating growth of cells and their metabolic activity. The T6P/SnRK1 mechanism offers an important new view of how the distribution of assimilates to organs, such as developing grains in cereal plants, is achieved. This review briefly summarizes the factors determining, and limiting, yield of wheat (particularly mass/grain which is highly conserved) and considers how T6P/SnRK1 might function to determine grain yield and might be altered to increase them. Increasing the potential rate of filling and mass/grain are ways in which total crop yield could be increased with good husbandry which maintains crop assimilation Cereal yields globally are not increasing, despite the greater production required to meet human demand. Careful targeting of T6P is showing much promise for optimization of source/sink for yield improvement and offers yet further possibilities for increasing sink demand and grain size in wheat.
Using goal analysis to drive improvements in performance and outcomes. - Journal of intellectual disabilities : JOID
Economic pressures for public health and human services systems to control budgets are increasing the need for demonstrating value of support services provided to persons with intellectual disabilities. In this article, we build from earlier work that presented a method for assessing goal attainment to expand the study of goal characteristics as a means to gain an improved understanding of individual outcomes and service performance. The study results suggest a positive relationship between targeting intentional skill teaching in person-centered planning and service delivery and increasing the ability of individuals to live more independently in communities with decreased levels of paid staff support. Additional areas meriting further exploration are presented and implications for current system trends are discussed.
Genetic engineering to improve plant performance under drought: physiological evaluation of achievements, limitations, and possibilities. - Journal of experimental botany
Fully drought-resistant crop plants would be beneficial, but selection breeding has not produced them. Genetic modification of species by introduction of very many genes is claimed, predominantly, to have given drought resistance. This review analyses the physiological responses of genetically modified (GM) plants to water deficits, the mechanisms, and the consequences. The GM literature neglects physiology and is unspecific in definitions, which are considered here, together with methods of assessment and the type of drought resistance resulting. Experiments in soil with cessation of watering demonstrate drought resistance in GM plants as later stress development than in wild-type (WT) plants. This is caused by slower total water loss from the GM plants which have (or may have-morphology is often poorly defined) smaller total leaf area (LA) and/or decreased stomatal conductance (g (s)), associated with thicker laminae (denser mesophyll and smaller cells). Non-linear soil water characteristics result in extreme stress symptoms in WT before GM plants. Then, WT and GM plants are rewatered: faster and better recovery of GM plants is taken to show their greater drought resistance. Mechanisms targeted in genetic modification are then, incorrectly, considered responsible for the drought resistance. However, this is not valid as the initial conditions in WT and GM plants are not comparable. GM plants exhibit a form of 'drought resistance' for which the term 'delayed stress onset' is introduced. Claims that specific alterations to metabolism give drought resistance [for which the term 'constitutive metabolic dehydration tolerance' (CMDT) is suggested] are not critically demonstrated, and experimental tests are suggested. Small LA and g (s) may not decrease productivity in well-watered plants under laboratory conditions but may in the field. Optimization of GM traits to environment has not been analysed critically and is required in field trials, for example of recently released oilseed rape and maize which show 'drought resistance', probably due to delayed stress onset. Current evidence is that GM plants may not be better able to cope with drought than selection-bred cultivars.
Hyperaromatic stabilization of arenium ions: a remarkable cis stereoselectivity of nucleophilic trapping of Î²-hydroxyarenium ions by water. - Journal of the American Chemical Society
Cis- and trans-1,2-dihydrodiol isomers of benzene undergo acid-catalyzed dehydration to form phenol. In principle the isomeric substrates react through a common Î²-hydroxybenzenium (cyclohexadienyl) carbocation. Notwithstanding, the isomers show a large difference in reactivity, k(cis)/k(trans) = 4500. This difference is reduced to k(cis)/k(trans) = 440 and 50 for the 1,2-dihydrodiols of naphthalene and 9,10-dihydrodiols of phenanthrene, respectively, and to 6.9 for the dihydrodiols of the nonaromatic 7,8-double bond of acenaphthylene. Because the difference in stabilities of cis- and trans-dihydrodiols should be no more than 2-3-fold, these results imply a high cis stereoselectivity for nucleophilic trapping of a Î²-hydroxyarenium cation by water in the reverse of the carbocation-forming reaction. This is confirmed by studies of the 10-hydroxy-9-phenanthrenium ion generated from aqueous solvolyses of the trans-9,10-bromohydrin derivative of phenanthrene and the monotrichloroacetate ester of the phenanthrene cis-9,10-dihydrodiol. The cis stereoselectivity of forward and reverse reactions is explained by the formation (in the "forward" reaction) of different conformations of carbocation from cis- and trans-dihydrodiol reactants with respectively Î²-C-H and Î²-C-OH bonds in pseudoaxial positions with respect to the charge center of the carbocation optimal for hyperconjugation. Formation of different conformations is constrained by departure of the (protonated) OH leaving group from a pseudoaxial position. The difference in stability of the carbocations is suggested to stem (a) from the greater hyperconjugative ability of a C-H than a C-OH bond and (b) from enhanced conjugation arising from the stabilizing influence of an aromatic ring in the no-bond resonance structures representing the hyperconjugation (C(6)H(6)OH(+) â†” C(6)H(5)OH H(+)). This is consistent with an earlier suggestion by Mulliken and a demonstration by Schleyer that the benzenium ion is subject to hyperconjugative aromatic stabilization. It is proposed that, in analogy with the terms homoconjugation and homoaromaticity, arenium ions should be considered as "hyperaromatic".Â© 2011 American Chemical Society
Hyperaromatic stabilization of arenium ions: cyclohexa- and cycloheptadienyl cations-experimental and calculated stabilities and ring currents. - Journal of the American Chemical Society
Measurements of pK(R) show that the cycloheptadienyl cation is less stable than the cyclohexadienyl (benzenium) cation by 18 kcal mol(-1). This difference is ascribed here to "hyperaromaticity" of the latter. For the cycloheptadienyl cation a value of K(R) = [ROH][H(+)]/[R(+)] is assigned by combining a rate constant for reaction of the cation with water based on the azide clock with a rate constant for the acid-catalyzed formation of the cation accompanying equilibration of cycloheptadienol with its trifluoroethyl ether in TFE-water mixtures. Comparison of pK(R) = -16.1 with pK(R) = -2.6 for the cyclohexadienyl cation yields the difference in stabilities of the two ions. Interpretation of this difference in terms of hyperconjugative aromaticity is supported by the effect of benzannelation in reducing pK(R) for the benzenium ion: from -2.6 down to -3.5 for the 1H-naphthalenium and -6.0 for the 9H-anthracenium ions, respectively. MP2/6-311+G** and G3MP2 calculations of hydride ion affinities of benzenium ions show an order of stabilities for substituents at the methylene group consistent with their hyperconjugative abilities, i.e., (H(3)Si)(2) > cyclopropyl > H(2) > Me(2)> (HO)(2) > F(2). Calculations of ring currents show a similar ordering. No conventional ring current is seen for the cycloheptadienyl cation, whereas currents in the F(2)-substituted benzenium ion are consistent with antiaromaticity. Arenium ions where the methylene group is substituted with a single OH group show characteristic energy differences between conformations, with C-H or C-OH bonds respectively occupying or constrained to axial positions favorable to hyperconjugation. The differences were found to be 8.8, 6.3, 2.4, and 0.4 kcal mol(-1) for benzenium, naphthalenium, phenanthrenium, and cyclohexenyl cations, respectively.Â© 2011 American Chemical Society
Hyperaromatic stabilization of arenium ions. - Organic letters
Benzene-cis- and trans-1,2-dihydrodiols undergo acid-catalyzed dehydration at remarkably different rates: k(cis)/k(trans) = 4500. This is explained by formation of a Î²-hydroxycarbocation intermediate in different initial conformations, one of which is stabilized by hyperconjugation amplified by an aromatic no-bond resonance structure (HOC(6)H(6)(+) â†” HOC(6)H(5) H(+)). MP2 calculations and an unfavorable effect of benzoannelation on benzenium ion stability, implied by pK(R) measurements of -2.3, -8.0, and -11.9 for benzenium, 1-naphthalenium, and 9-phenanthrenium ions, respectively, support the explanation.
American Pediatric Surgical Association New Technology Committee review on video-assisted thoracoscopic surgery for childhood cancer. - Journal of pediatric surgery
Although the use of minimally invasive surgical (MIS) techniques for children with cancer is being practiced by some, its role remains unclearly defined. The purpose of this review was to describe the current literature on MIS for thoracic and mediastinal lesions in children.We performed a literature search for English studies that evaluated MIS techniques for biopsy or resection in children with suspected or established cancer. Only studies with greater than 20 patients were included in the review.Ten studies were included for review. Each represented institutional retrospective reviews of experience. Seven were single-institution studies, and 3 were multi-institutional. There were no prospective nor randomized identified.Based on primarily retrospective and observational data, the use of MIS for children with cancer who have pulmonary and mediastinal lesions seems to be effective and safe. Ideally, prospective studies are needed to evaluate this further.Copyright Â© 2010 Elsevier Inc. All rights reserved.
Test of time: a case study in the functioning of social systems as a defence against anxiety: rereading 50 years on. - Clinical child psychology and psychiatry
In this paper I revisit Isabel Menzies's classic 'nursing paper' (I.E.P. Menzies . A case-study in the functioning of social systems as a defence against anxiety: A report on a study of the nursing service of a general hospital. Human Relations, 13, 95-121). I outline the main findings of the paper and connect it to the major theoretical developments made by the Tavistock Institute of Human Relations and consider the current relevance of the paper in the contemporary field of health and social care.
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