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Selected AbstractsMyogenesis contributes to functional electrical stimulation (fes)-induced recovery of myofiber excitability and mass of human long-term denervated muscles in spinal cord injury (SCI)JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2004H Kern Many months after SCI, when an irreversible injury involves lower motoneurons, severe atrophy of human muscle is complicated by fibrosis and fat substitution (denervated, degenerated muscle, DDM). We will describe the effects of long-term lower motoneuron denervation on human muscle and present the structural results of muscle trained using FES. Antibody for embryonic myosin demonstrates that sustained myogenesis occurs in human DDM. By electron microscopy we studied: a) the overall structure of fibers and myofibrils in long-term DDM, including the effects of FES, and b) the structure and localization of calcium release units, or triads, the structure deputed to activate muscle contraction during excitation-contraction coupling (ECC). The poor excitability of human long-term DDM fibers during the first stages of FES training could be explained in terms of spatial disorder of both the ECC and contractile apparati. The structural studies are extremely encouraging since they demonstrate that FES training is effective in reverting long-term DDM atrophy and in maintaining the trophic state of the recovered myofibers. [source] Pacific Salmon Extinctions: Quantifying Lost and Remaining DiversityCONSERVATION BIOLOGY, Issue 4 2007RICHARD G. GUSTAFSON biodiversidad; diversidad de salmones; extinción de poblaciones; historia de vida de salmones Abstract:,Widespread population extirpations and the consequent loss of ecological, genetic, and life-history diversity can lead to extinction of evolutionarily significant units (ESUs) and species. We attempted to systematically enumerate extinct Pacific salmon populations and characterize lost ecological, life history, and genetic diversity types among six species of Pacific salmon (Chinook [Oncorhynchus tshawytscha], sockeye [O. nerka], coho [O. kisutch], chum [O. keta], and pink salmon [O. gorbuscha] and steelhead trout [O. mykiss]) from the western contiguous United States. We estimated that, collectively, 29% of nearly 1400 historical populations of these six species have been lost from the Pacific Northwest and California since Euro-American contact. Across all species there was a highly significant difference in the proportion of population extinctions between coastal (0.14 extinct) and interior (0.55 extinct) regions. Sockeye salmon (which typically rely on lacustrine habitats for rearing) and stream-maturing Chinook salmon (which stay in freshwater for many months prior to spawning) had significantly higher proportional population losses than other species and maturation types. Aggregate losses of major ecological, life-history, and genetic biodiversity components across all species were estimated at 33%, 15%, and 27%, respectively. Collectively, we believe these population extirpations represent a loss of between 16% and 30% of all historical ESUs in the study area. On the other hand, over two-thirds of historical Pacific salmon populations in this area persist, and considerable diversity remains at all scales. Because over one-third of the remaining populations belong to threatened or endangered species listed under the U.S. Endangered Species Act, it is apparent that a critical juncture has been reached in efforts to preserve what remains of Pacific salmon diversity. It is also evident that persistence of existing, and evolution of future, diversity will depend on the ability of Pacific salmon to adapt to anthropogenically altered habitats. Resumen:,Las extirpaciones generalizadas de poblaciones y la consecuente pérdida de diversidad ecológica, genética y de historia natural puede llevar a la extinción de unidades evolutivamente significativas (UES) y especies. Intentamos enumerar sistemáticamente a las poblaciones extintas de salmón del Pacífico y caracterizar a los tipos de diversidad ecológica, de historia natural y genética de seis especies de salmón del Pacífico Oncorhynchus tshawytscha, O. nerka, O. kisutch, O. keta, y O. gorbuscha; y trucha O. mykiss en el occidente de Estados Unidos. Estimamos que, colectivamente, se ha perdido a 29% de casi 1400 poblaciones históricas de estas seis especies en el Pacífico Noroeste y California desde la colonización europea. En todas las especies hubo una diferencia altamente significativa en la proporción de extinción de poblaciones entre regiones costeras (0.14 extintas) e interiores (0.55 extintas). O. nerka (que típicamente cría en hábitats lacustres) y O. tshawytscha (que permanece en agua dulce por muchos meses antes del desove) tuvieron pérdidas poblacionales significativamente mayores que las otras especies y tipos de maduración. Se estimó que las pérdidas agregadas de componentes mayores de la biodiversidad ecológica, de historia natural y genética en todas las especies fueron de 33%, 15% y 27%, respectivamente. Colectivamente, consideramos que estas extirpaciones de poblaciones representan una pérdida entre 16% y 30% de todas las UES históricas en el área de estudio. Por otro lado, más de dos tercios de las poblaciones históricas de salmón del Pacífico persisten en esta área, y aun hay considerable diversidad en todas las escalas. Debido a que más de un tercio de las poblaciones restantes pertenecen a especies enlistadas como amenazadas o en peligro en el Acta de Especies en Peligro de E. U. A., es evidente que se ha llegado a una disyuntiva crítica en los esfuerzos para preservar lo que queda de la diversidad de salmón del Pacífico. También es evidente que la persistencia de la diversidad existente, y su futura evolución, dependerá de la habilidad del salmón del Pacífico para adaptarse a hábitats alterados antropogénicamente. [source] Pre-clinical studies of pramipexole: clinical relevanceEUROPEAN JOURNAL OF NEUROLOGY, Issue 2000J. P. Hubble This paper reviews the preclinical study of the novel dopamine agonist pramipexole and its use in early Parkinson's disease (PD). Emphasis will be given to those properties distinguishing this drug from other dopamine agonists, the relevance of the preclinical data to clinical trial results in early PD, and the putative neuroprotective properties of the compound. The conventional dopamine agonists are ergot-derived compounds that are most widely used as adjunctive therapies in advancing Parkinson's disease (PD). Examples of conventional agonists are bromocriptine and pergolide. Pramipexole is an aminobenzothiazole compound, recently introduced for the treatment of both early and advanced PD. Its nonergot structure may reduce the risk of side-effects, considered unique to ergot drugs, such as membranous fibrosis. Pramipexole is a full dopamine agonist with high selectivity for the D2 dopamine receptor family. This family includes the D2, D3 and D4 receptor subtypes. Pramipexole has a 5- to 7-fold greater affinity for the D3 receptor subtype with lower affinities for the D2 and D4 receptor subtypes. The drug has only minimal ,2 -adrenoceptor activity and virtually no other receptor agonism or antagonism. The optimal dopamine receptor activation for the safe and effective treatment of PD is not known. Findings in animal models and clinical studies indicate that activation of the postsynaptic D2 receptor subtype provides the most robust symptomatic improvement in PD. Given its pharmacological profile, it is not surprising that pramipexole was found to be effective in ameliorating parkinsonian signs in animal models. This therapeutic effect has been confirmed in clinical trials in both early and advanced PD. In early disease, it provides a clear reduction in the chief motor manifestations of PD and improved activities of daily living. Perhaps most striking is the large number of clinical trial patients who have remained on pramipexole monotherapy for many months. The majority of these subjects have been maintained on pramipexole for an excess of 24 months without requiring additional symptomatic treatment with levodopa. This is in contrast to the general clinical experience with older conventional agonists. Pramipexole also has a favourable pharmacokinetic profile. It is rapidly absorbed with peak levels appearing in the bloodstream within 2 h of oral dosing. It has a high absolute bioavailability of > 90% and can be administered without regard to meals. It has no significant effects on other antiparkinson drugs such as levodopa or selegiline. Its excretion is primarily renal and, thus, has little or no impact on hepatic cytochrome P450 enzymes or other related metabolic pathways. Pramipexole has also been theorized to have ,neuroprotectant' properties. Oxyradical generation is posited as a cause or accelerant of brain nigral cell death in PD. Pramipexole stimulates brain dopamine autoreceptors and reduces dopamine synthesis and turnover which may minimize oxidative stress due to dopamine metabolism. Furthermore, the compound has a low oxidation potential that may serve as an oxyradical scavenger in the PD brain. In summary, pramipexole is a new antiparkinson medication found to have unique dopamine agonist characteristics and putative neuroprotective properties. [source] Causes of hair loss and the developments in hair rejuvenationINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2002D. H. Rushton Synopsis Hair is considered to be a major component of an individual's general appearance. The psychological impact of hair loss results in a measurably detrimental change in self-esteem and is associated with images of reduced worth. It is not surprising that both men and women find hair loss a stressful experience. Genetic hair loss is the major problem affecting men and by the age of 50, up to 50% will be affected. Initial attempts to regenerate the lost hair have centred on applying a topical solution of between 2% to 5% minoxidil; however, the results proved disappointing. Recently, finasteride, a type II 5, reductase inhibitor has been found to regrow a noticeable amount of hair in about 40% of balding men. Further developments in treatments have lead to the use of a dual type I and type II inhibitor where 90% of those treated regrow a noticeable amount of hair. In women the major cause of hair loss before the age of 50 is nutritional, with 30% affected. Increased and persistent hair shedding (chronic telogen effluvium) and reduced hair volume are the principle changes occurring. The main cause appears to be depleted iron stores, compromised by a suboptimal intake of the essential amino acid l -lysine. Correction of these imbalances stops the excessive hair loss and returns the hair back to its former glory. However, it can take many months to redress the situation. Résumé Les cheveux sont considérés comme étant une composante majeure de l'aspect général d'un individu. L'impact psychologique de la perte des cheveux conduit à une diminution mesurable de l'estime de soi et s'associe à des images de contexte négatif. Il n'est pas surprenant que les hommes comme les femmes ressentent la perte de cheveux comme une expérience stressante. La perte génétique des cheveux est le problème principal qui touche les hommes et autour de l'âge de 50 ans, jusqu'à 50% seront concernés. Les premières tentatives de régénération des cheveux perdus se sont focalisées sur l'application topique d'une solution comprenant entre 2% et 5% de minoxidil; cependant, les résultats se sont avérés décevants. Récemment, le finastéride, un inhibiteur de la 5,-réductase de type II s'est avéré permettre la repousse d'une quantité significative de cheveux chez environ 40% des hommes dégarnis. Les développements ultérieurs des traitements ont conduit à l'utilisation d'un inhibiteur associant type I et type II pour lequel 90% des personnes traitées constatent une repousse significative des cheveux. Chez les femmes la cause principale de la perte des cheveux avant l'âge de 50 ans est d'origine nutritionnelle, avec 30% de la population affectée. Une perte de cheveux persistante et croissante (telogen effluvium chronique) et un volume des cheveux réduit sont les principaux effets qui se produisent. La cause principale semble être des réserves de fer épuisées, associées à une prise insuffisante de l'acide aminé essentiel L-lysine. La correction de ces déséquilibres stoppe la perte excessive de cheveux et rend aux cheveux leur éclat d'antan. Cependant, plusieurs mois peuvent être nécessaires pour redresser la situation. [source] Prevalence of vaccine-derived polioviruses in stools of immunodeficient children in South AfricaJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2006D.N. Pavlov Abstract Aims:, The aim of the study was to determine the prevalence of vaccine-derived polioviruses (VDPVs) in stool specimens of immunodeficient patients such as HIV-positive children (including those with an AIDS indicator condition, according to the Centres for Disease Control and Prevention classification) by applying various molecular techniques. Methods and Results:, A total of 164 stool samples from HIV-positive children and 23 stool samples from healthy immunocompetent children (the control group) were analysed during 2003 and 2004. By applying a reverse transcription polymerase chain reaction (RT-PCR) in combination with a nested PCR, a total of 54 enteroviruses were detected in the stool specimens of the immunodeficient children. The use of restriction enzymes and a Sabin specific RT-triplex PCR confirmed the presence of 13 polioviruses (PVs), such as seven Sabin PV type 1, four Sabin PV type 3 and two Sabin PV type 2 isolates. The 5,untranslated region and the VP1 capsid-encoding protein of the 13 PVs and the three PVs from the stools of the immunocompetent children were partially sequenced and their genetic relatedness was deduced from the constructed phylogenetic trees. The majority of the PVs isolated from the stools of the immunodeficient children (10 of 13 isolates) were classified as ,oral poliovirus vaccine (OPV)-like viruses', as these isolates had close sequence relationships (>99% in VP1 nucleotide sequences) to the original Sabin PV vaccine strains. Three PVs showed ,99% VP1 sequence identity to the Sabin PV vaccine strains and were classified as ,suspected' immunodeficient VDPVs (iVDPVs). All of the OPV-like isolates and the ,suspected' iVDPVs carried mutations at specific positions in their partially sequenced regions, which have been associated with reversion of the attenuated Sabin PV vaccine strains to increased neurovirulence. Conclusions:, Thus, this study adds further evidence to the observation that immunodeficient individuals may excrete OPV strains with potential neurovirulent phenotypes. Significance and Impact of the Study:, Prolonged excretion of PVs by immunodeficient individuals is of major concern, because continued replication of PVs in the human gut could result in the reversion of these viruses to greater neurovirulence. When exposed to OPV, immunodeficient patients may become chronically infected, spreading potentially neurovirulent VDPVs for many months or years to close contacts and children who are no longer being vaccinated after termination of OPV vaccination in the near future. [source] An exploratory study of anxiety in carers of stroke survivorsJOURNAL OF CLINICAL NURSING, Issue 13-14 2010Nan Greenwood Aims and objectives., To investigate anxiety in informal carers of stroke survivors in the first three months after discharge. Background., Informal carers, also called caregivers, play a vital role in supporting stroke survivors. However, caring for stroke survivors can have adverse consequences amongst carers such as burden, stress and reduced quality of life. Emotional distress is also commonly reported but anxiety has received less attention than depression. Design., Prospective, longitudinal, descriptive study. Method., Forty-five carers completed the Hospital Anxiety and Depression Scale on two occasions , within one month and at three months after discharge from stroke and rehabilitation units. Results., Carers were more likely to have scores indicating anxiety than depression. In the first month, half the carers (51·1%) scored in the cut-off for anxiety and a third were in the cut-off for depression (31·1%). At three months, the picture was very similar with nearly identical proportions in the anxious and depressed categories (48·9% and 28·9%, respectively). Changes in numbers of cases of anxiety and depression and in mean anxiety scores were non-significant but there was a significant decrease in depression scores (p = 0·048). Fourteen carers (31·1%) at one month and eleven (24·4%) at three months fell into both anxious and depressed categories. Conclusions., Anxiety is a relatively neglected emotional outcome in stroke carers. Our study suggests anxiety is an important issue very early in caring whilst other research suggests it remains prevalent for many months. Given the significant role carers play in rehabilitation of stroke survivors, greater recognition of their emotional state is required. Further, longitudinal research with larger sample sizes from a range of geographical areas and improved understanding of factors associated with anxiety is needed. Relevance to clinical practice., Nurses working in the community are ideally placed to identify and support carers suffering from anxiety. [source] Short-term survival and long-term mortality of Acacia drepanolobium after a controlled burnAFRICAN JOURNAL OF ECOLOGY, Issue 3 2008B. D. Okello Abstract We investigated the short- and long-term effects of a controlled burn in Acacia drepanolobium woodland in Laikipia, Kenya in 1998. Fire temperatures averaged 250°C at ground level, with a maximum of over 500°C, but were rarely >100°C at 1.5 m above the ground or more. Nine months after the fire, virtually all A. drepanolobium trees had survived the fire. Some smaller trees were burnt to ground level, but most were only ,top-killed' and had coppiced. Taller trees suffered less damage than smaller trees. However, a 2003 satellite image suggested a dramatic reduction in A. drepanolobium canopy cover at the site. A survey of the site in 2006 revealed that the density of larger A. drepanolobium trees was nearly three times greater in adjacent control areas than in the old burn, with a lesser reduction in the density of smaller trees. These data suggest that short-term measures of postburn survivorship may be deceptive, and that an additional source of tree mortality (perhaps elephants) was concentrated on trees in burned areas, even many months after the burn, with long-term consequences for tree and ecosystem dynamics. Résumé Nous avons étudié les effets à court et à long terme d'un feu contrôlé dans la forêt àAcacia drepanolobium située à Laikipia, au Kenya, en 1998. La température du feu avoisinait les 250°C au niveau du sol, avec un maximum de 500°C, mais elle dépassait rarement les 100°C à 1,5 mètre au-dessus du sol et plus haut. Neuf mois après le feu, pratiquement tous les Acacia drepanolobium avaient survécu. Certains des arbres plus petits avaient brûlé jusqu'au ras du sol, mais chez la plupart, seule la partie aérienne avait brûlé et ils avaient fait des repousses. Les arbres plus grands avaient subi moins de dommages. Pourtant, une image satellite prise en 2003 a suggéré une réduction spectaculaire de la canopée d'A. drepanolobiumà cet endroit. Une étude du site réalisée en 2006 a révélé que la densité des plus grands A. drepanolobiumétait près de trois fois plus forte dans les zones de contrôle adjacentes que sur le site brûlé, où la densité des plus petits arbres était moins réduite. Ces données suggèrent que les mesures de la survie postincendie faites à court terme peuvent être trompeuses, et qu'une source supplémentaire de mortalité des arbres (peut-être des éléphants) s'est concentrée sur les arbres des zones brûlées, même plusieurs mois plus tard, avec des conséquences à long terme pour les arbres et la dynamique de l'écosystème. [source] Barriers that delay children and young people who are dependent on mechanical ventilators from being discharged from hospitalJOURNAL OF CLINICAL NURSING, Issue 1 2002Cert.Ed.MILT, JANE NOYES MSc ,,A qualitative study of user perspectives published previously by the author found that children and young people who are dependent on ventilators spend many months and in some cases years in hospital when they no longer had a medical need or wanted to be there. ,,This second paper is drawn from the same qualitative study and reports on the barriers that the children and young people who are dependent on ventilators, and their parents, described as important factors in preventing their discharge from hospital. ,,Six issues were identified as significant barriers that prevented the children and young people from being discharged. These were: the attitudes of professionals; the lack of joint commissioning and accounting responsibility; general poor management both within the health service and in collaborating with other services; complex social issues; housing problems; and a general lack of auditing and outcome measures. ,,The generalizability of the findings is unknown. However, recommendations are made in relation to the need to establish joint commissioning and accounting responsibility for care and services, and to establish outcome measures to monitor the effectiveness and appropriateness of the care and services provided. [source] "Whippets"-Induced Cobalamin Deficiency Manifesting as Cervical MyelopathyJOURNAL OF NEUROIMAGING, Issue 3 2004Alan L. Diamond ABSTRACT Background. Nitrous oxide (N O) is inhaled in anesthesia and as a recreational drug from whipped cream dispensers. Its abuse reaches ,10% in some age groups. By inactivating cobalamin (Cbl) (vitamin B12), N O can cause neurologic and hematologic manifestations. We present a case of N O-induced Cbl deficiency presenting as cervical myelopathy. Case History. After regularly inhaling N O for many months, a 31-year-old man developed limb paresthesiae and ataxia over 3 months. Examination revealed finger pseudoathetosis, hyporeflexia, decreased sensation, and gait ataxia. Brain magnetic resonance imaging (MRI) was normal, but the posterior columns of the cervical and upper thoracic cord revealed patchy nonenhancing hyperintense lesions. Serum Cbl was 98 pg/mL (normal = 170,900 pg/mL). Cbl replacement led to recovery within 3 months.Discussion. This patient presented with the symptoms and signs of Cbl deficiency. The MRI lesions in the posterior columns aided the diagnosis. Physicians need to have a high level of suspicion in cases of unexplained Cbl deficiency and myelopathy. [source] The stem canker (blackleg) fungus, Leptosphaeria maculans, enters the genomic eraMOLECULAR PLANT PATHOLOGY, Issue 3 2005T. ROUXEL SUMMARY Leptosphaeria maculans is the most ubiquitous pathogen of Brassica crops, and mainly oilseed brassicas (oilseed rape, canola), causing the devastating ,stem canker' or ,blackleg'. This review summarizes our current knowledge on the pathogen, from taxonomic issues to specific life traits. It mainly illustrates the importance of formal genetics approaches on the pathogen side to dissect the interaction with the host plants. In addition, this review presents the main current research topics on L. maculans and focuses on the L. maculans genome initiative recently begun, including its main research issues. Taxonomy:,Leptosphaeria maculans (Desm.) Ces. & de Not. (anamorph Phoma lingam Tode ex Fr.). Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes (Loculoascomycetes), Order Pleosporales, Genus Leptosphaeria, Species maculans. Host range:, cultivated Brassicas such as Brassica napus (oilseed rape, canola), B. rapa, B. juncea, B. oleracea, etc., along with numerous wild crucifers species. Arabidopsis thaliana was recently reported to be a potential host for L. maculans. Primary disease symptoms are greyish-green collapse of cotyledon or leaf tissue, without a visible margin, bearing tiny black spots (pycnidia). The fungus then develops an endophytic symptomless growth for many months. Secondary symptoms, at the end of the growing season, are dry necroses of the crown tissues with occasional blackening (stem canker or blackleg) causing lodging of the plants. Pseudothecia differentiate on leftover residues. Seedling damping-off and premature ripening are also reported under certain environmental conditions. Useful websites:,Leptosphaeria maculans sequencing project at Genoscope: http://www.genoscope.cns.fr/externe/English/Projets/Projet_DM/organisme_DM.html; the SECURE site: http://www.secure.rothamsted.ac.uk/ the ,Blackleg' group at the University of Melbourne: http://www.botany.unimelb.edu.au/blackleg/overview.htm [source] Changes in phosphine sorption in wheat after storage at two temperaturesPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 11 2009Gregory J Daglish Abstract BACKGROUND: Wheat can be stored for many months before being fumigated with phosphine to kill insects, so a study was undertaken to investigate whether the sorptive capacity of wheat changes as it ages. Wheat was stored at 15 or 25 °C and 55% RH for up to 5.5 months, and samples were fumigated at intervals to determine sorption. Sealed glass flasks (95% full) were injected with 1.5 mg L,1 of phosphine based on flask volume. Concentrations were monitored for 11 days beginning 2 h after injection. Some wheat samples were refumigated after a period of ventilation. Several fumigations of wheat were conducted to determine the pattern of sorption during the first 24 h. RESULTS: Phosphine concentration declined exponentially with time from 2 h after injection. Rate of sorption decreased with time spent in storage at either 15 or 25 °C and 55% RH. Rate of sorption tended to be lower when wheat was refumigated, but this could be explained by time in storage rather than by refumigation per se. The data from the 24 h fumigations did not fit a simple exponential decay equation. Instead, there was a rapid decline in the first hour, with phosphine concentration falling much more slowly thereafter. CONCLUSIONS: The results have implications for phosphine fumigation of insects in stored wheat. Both the time wheat has spent in storage and the temperature at which it has been stored are factors that must be considered when trying to understand the impact of sorption on phosphine concentrations in commercial fumigations. Copyright © The state of Queensland (through the Department of Employment, Economic Development and Innovation) 2009. Published by John Wiley and Sons, Ltd. [source] Photo(chemo) therapy for vitiligoPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 1 2003Rik Roelandts Vitiligo has always been difficult to treat. Several modes of treatment are available, but the therapeutic effect varies greatly, and rarely does one achieve complete repigmentation. One of the most efficient treatment methods is photo(chemo) therapy. Already in ancient Egypt, vitiligo lesions were treated with extracts of the Ammi maius plant followed by exposure to the sun. This principle is at the basis of the photochemotherapy or PUVA therapy, whereby UVA irradiations are given 2 h after administration of 8-methoxypsoralen, a photosensitizer. Another efficient treatment form is UVB phototherapy, particularly narrow-band UVB. This not only gives good therapeutic results but also has the advantage of eliminating the need for a photosensitizer. All these treatments must be applied for many months to be efficient. They can also be combined with various surgical skin-grafting techniques. A newer approach is targeted UVB phototherapy, whereby xenon-chloride lasers or monochromatic excimer light is used. [source] The Dog That Did Not Bark: Insider Trading and CrashesTHE JOURNAL OF FINANCE, Issue 5 2008JOSE M. MARIN ABSTRACT This paper documents that at the individual stock level, insiders' sales peak many months before a large drop in the stock price, while insiders' purchases peak only the month before a large jump. We provide a theoretical explanation for this phenomenon based on trading constraints and asymmetric information. A key feature of our theory is that rational uninformed investors may react more strongly to the absence of insider sales than to their presence (the "dog that did not bark" effect). We test our hypothesis against competing stories, such as insiders timing their trades to evade prosecution. [source] Developmental disorders of glucose metabolism in infantsCHILD: CARE, HEALTH AND DEVELOPMENT, Issue 2002R. Hume Abstract Background Developmental failures to adequately control postnatal blood glucose levels are common in the transition from fetal to infant life and can persist for many months. The standard method of functionally measuring hepatic glucose production and/or disordered glucose production is the response to a glucagon tolerance test. Method We adapted the standard glucagon tolerance test used for children and adults for use in preterm infants. 79 consecutive preterm infants gestational age range 25,36 weeks (mean 32.2 weeks), mean birth weight 1.66 kg admitted to the Neonatal Intensive Care Unit, Ninewells Hospital, Dundee and who survived to discharge home were recruited into the study. At the time of discharge home the characteristics of the group were as follows: adjusted mean gestational age 36.7 weeks, mean discharge weight 2.23 kg. Results In this study of preterm infants the maximal increase in plasma glucose following administration of a glucagon tolerance test is 1.39 ± 07 mmol/L, n = 78 (range 0,3.98 mmol/L). Conclusions An increase in plasma glucose of less than 4 mmol/L is considered abnormal in adults following administration of a fasting glucagon tolerance test. The responses of preterm infants and adults to glucagon are clearly different. The attenuated response to glucagon in the preterm infants is consistent with the low levels of hepatic glucose-6-phosphatase activity in premature infants as glucose-6-phosphatase is the terminal step of the two main pathways of liver glucose production. [source] |