Are prealbumin plasma levels linked to amino acid supply from peripheral tissues in liver cirrhosis?

Summary Prealbumin plasma level is considered a good index of liver function in liver cirrhosis. However, plasma protein levels depend not only on liver function, but also on amino acid supply which is consequent to nutritional status.In 12 cirrhotics we measured prealbumin plasma levels and the lower limb venous-artero difference of amino acid plasma levels in blood samples taken from femoral vein and femoral artery in post-absorptive conditions considered as a direct index of protein release from peripheral tissues and an indirect index of protein nutritional status.In arterial and in venous plasma amino acid sum was 1.86±0.40 (mean + sd) and 2.00 ± 0.04 mMol/l respectively.Prealbumin plasma levels were found directly correlated with the venousartero difference of amino acid plasma levels (r = 0.57p < 0.05) and of glutamate + glutamine levels (r = 0.73p < 0.007).In conclusions, these data suggest that prealbumin plasma levels are linked to amino acid supply from peripheral tissues in cirrhotics.     

立地性日照长短与甜橙生长发育的相关性

甜橙[Citrus sinensis(L.)Osbesk,本文中均指雪柑(Citrus sinensis var.sekkan)]对日照的需要量,比温州蜜柑(Citrus reticulata var.unshiu)等桔类要少些,即温州蜜柑比甜橙和杂柑类的耐荫性稍弱。然而,究竟可少到什么临界值呢?同一果园,同一管理水平,同一树龄,由于坡向、地形等的不同,而     

Pastoral dairy marketing and household wealth interactions and their implications for calves and humans in Ethiopia

Surveys of pastoral households in a semi-nomadic Borana community during 1987–1988 were used to test the hypothesis that poorer families living closest to a market town would be most affected by the enhanced opportunity to sell dairy products, which would intensify competition between people and calves for milk and have negative implications for calf management. These poorer families indeed reported the highest rates of milk offtake per cow, and the milk increment was probably sold to purchase more grain for human consumption at the expense of milk intake for the calf. Consequently, this strategy may increase the susceptibility of malnourished calves to disease, especially those from lower-producing dams. Benefits of improved human energy intake from grain and retention of livestock capital must be weighed against risks of calf death and possible malnutrition of people from milk restriction when assessing dairy marketing trade-offs that are most acute for the poor. Opportunity to sell dairy products at favorable terms of trade helps the poorest people survive, and their risks could be mitigated by policies that facilitate grain marketing in the rangelands and interventions that improve calf feeding management, diversify human diets, and create alternative opportunities for women to generate income. The households postulated to be most at risk were identified from a complex, but logical, interaction among factors of distance to market, household wealth, and the quality of milking cows held. This indicates that targeting such needy groups for development assistance may require a more detailed and interdisciplinary analysis of production systems than is commonly practiced.     

Transgenic animals as a tool for studying the effect of the c-myc proto-oncogene on cardiac development

Transgenic animals provide a model system to elucidate the role of specific proteins in development. This model is now being used increasingly in the cardiovascular system to study cardiac growth and differentiation. During cardiac myocyte development a transition occurs from hyperplastic to hypertrophic growth. In the heart the switch from myocyte proliferation to terminal differentiation is synchronous with a decrease in c-myc mRNA abundance. To determine whether c-myc functions to regulate myocyte proliferation and/or differentiation, we examined the in vivo effect of increasing c-myc expression during fetal development and of preventing the decrease in c-myc mRNA expression that normally occurs during myocyte development. The model system used was a strain of transgenic mice exhibiting constitutive expression of c-myc mRNA in cardiac myocytes throughout development. Increased c-myc mRNA expression is associated with both atrial and ventricular enlargement in the transgenic mice. This increase in cardiac mass is secondary to myocyte hyperplasia, with the transgenic hearts containing greater than twice as many myocytes as nontransgenic hearts. The results of this study indicate that constitutive expression of c-myc mRNA in the heart during development results in enhanced hyperplastic growth, and suggest a regulatory role for the c-myc protooncogene in cardiac myogenesis.     

The development of the Jamming Avoidance Response (JAR) in Eigenmannia: An innate behavior indeed

Summary In its Jamming Avoidance Response (JAR), the gymnotiform electric fish Eigenmannia shifts its electric organ discharge (EOD) frequency away from similar interfering frequencies. Continual behavioral measurements were carried out in 164 juvenile fish until a correct JAR emerged. Sixty-four of these fish were raised in complete isolation, the remainder in a community of their siblings. A correct JAR emerged in fish of 1.2–1.6 cm in body length, corresponding to a developmental age of 24–32 days. In 6 of 164 fish, the emergence of a correct JAR followed an interim appearance of an incorrect JAR, which involved frequency shifts in the direction opposite to those of a correct JAR. The fish raised in isolation developed the same forms of behavior and showed the same sequence in their appearance as did socially raised fish. This indicates that the JAR and its developmental schedule are innate. The appearance of an incorrect JAR suggests initial errors or incompleteness in the wiring of central nervous connections. A correct JAR ultimately emerged even if a stimulus regimen was offered that rewarded frequency shifts in the direction opposite to those of a correct JAR. This indicates that the development of the JAR is immune to experimental alterations of sensory experience.Abbreviations Df frequency difference between a jamming stimulus and fish's EOD - ELL electrosensory lateral line lobe - EO electric organ - EOD electric organ discharge - JAR Jamming Avoidance Response - nE nucleus electrosensorius - nE subnucleus of nE, causing drop of EOD frequency - nE subnucleus of nE, causing rise of EOD frequency - Pn pacemaker nucleus - PPn prepacemaker nucleus     

Changes in free amino acid concentrations in serum,brain, and CSF throughout embryogenesis

Using the developing chick embryo as a model and a very sensitive micromethod for amino acid analysis, a complete analysis is presented of the developmental changes in free amino acid concentration in the blood, in the CSF, and in two different brain regions (optic lobe and frontal lobe) of the chick embryo (from day 4 of incubation, until day 5 post hatching). The developmental profile of Lys is the only one that is almost identical in all three compartments. The developmental profiles of the serum and of the brain are very similar for Arg and Phe, less so for Leu and Gly, and towards the end of the embryonic period, similar also for Val, Ile, Trp, and Met. The amino acid concentrations in the CSF are either much lower than in serum and brain already at the earliest stages, or they progressively decline to levels lower than those in brain and serum, most rapidly between day 6 and 8 of embryonic life. The concentrations of neuroactive amino acids (Gln, Glu, Asp, GABA, Tau, and Gly) in both brain regions begin to increase very early, and continue to rise, except Tau, which goes through a maximum at day 8. Comparative analysis of the developmental profiles of each amino acid in serum, brain, and CSF reveals that the blood supply and the cellular uptake, retention, and metabolism by neural cells are the major determinants of the free amino acid pool of the developing brain.     

Seasonal cycles of reserves in relation to reproduction inSebastes

Synopsis Seasonal cycles of reserve deposition and utilization in many fishes, amphibians and reptiles alleviate temporal mismatches of energy supply and demand. Utilization of reserves can be related to maintenance during periods of reduced food supply, to reproduction, particularly during periods of poor food availability, and to migration. Published data on the seasonal cycles of reserves and reproduction inSebastes suggest that reserves are important for maintenance during wintertime periods of low food availability. Unlike many other ectothermic vertebrates, some species ofSebastes deposit fat reserves at the same time as gametogenesis, a pattern consistent with the longevity and iteroparity evident in the genus. Other species ofSebastes have similar seasonal timing of fat cycles, but since reproduction takes place later in the year, the decline in reserves during winter coincides with the main period of reproductive activity. The significance of this is not clear. Interspecific differences in amounts of reserves may be related to geographical differences in the seasonality or abundance of food. Intraspecific variation in reserves, marked most strongly by allometry of reserves with regard to fish legth, bears further study, since it may link the proces of sexual maturation and the responses of repeat spawners to variability in food supply and other environmental factors.     

Issues related to mineralized tissue biology in human evolutionary research

This comunication has two primary aims concerned with mineralized tissue biology (e.g. hard tissue biology of bone and tooth) research in human evolutionary studies: First, to introduce the literature and the methods (at the time of this symposium) so that one has an idea of the nature of this research and where one can go for details of the methodologies, etc; Second — and of primary concern here — to discuss issues that have come to light as a result of these studies mainly because of its recent beginnings as a subfield within paleoanthropology. Issues related to skeletal studies include; 1) whether different cortical surface pattens and bone tissue types influence the appearance and interpretation of bone growth activity states; 2) if SEM analyses of cortical surfaces in fossil hominids allow one to construct meaningful representations of remodeling patterns; 3) whether these representations can be used in phylogenetic arguments; and 4) how intraspecific variability would affect these issues. Issues related to dental studies include: 1) the relationship between the rate and pattern of eraly hominid dental development; 2) experimental support for the calibration of eraly hominid dental developmental rates; and 3) whether replica techniques are suitable for microanatomical studies of these sorts.     

Survival and development of Pieris brassicae larvae upon application of sublethal doses of chlordimeform

Larvae of the large cabbage white butterfly, Pieris brassicae L. are important pests of cruciferous crops. Third and fifth instars were treated topically with sublethal doses of the formamidine pesticide chlordimeform. A number of excitable actions were induced but they did not persist beyond 24 hours. Following the initial period, however, subsequent development was delayed and mortality increased, particularly when third instars were treated. Dosing fifth-instar larvae caused few further deaths. A link is suggested between these results and the nutritional status of the insects, and they are discussed in terms of how they might contribute towards control.

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Résumé Les chenilles de troisième et cinquième stades de P. brassicae L. ont reçu une application superficielle de chlordiméforme, insecticide à la formamidine. Les doses inférieures à 335 g/g ont été sublétales, provoquant plusieurs formes d'excitation. Bien que leur comportement soit redevenu normal en 24 heures, les troisièmes stades traités ont eu leur développement retardé et une mortalité accrue. Le traitement des chenilles plus âgées a eu moins d'effets. Une relation est suggérée entre ces observations et le régime alimentaire de cet insecte; une réduction de l'alimentation, plus importante chez les chenilles de troisième que de cinquième stade de P. brassicae, accompagne le début des altérations du comportement provoquées par le chlordiméforme. La discussion porte sur le mécanisme de contrôle sublétal du chlordiméforme, impliquant des effects immédiats et retardés.