Discovery of MicroRNAs from Batrachuperus yenyuanensis Using Deep Sequencing and Prediction of Their Targets.

MicroRNAs (miRNAs), a family of ∼22-nucleotide non-coding single-stranded RNA molecules, are considered as key post-transcriptional regulators of gene expression that regulate various biological processes in living organism. Many miRNAs have been identified in animals; however, few have been reported in Hynobiidae species. The present study is aimed to identify a full repertoire of miRNAs in Batrachuperus yenyuanensis (Yenyuan stream salamander), which would significantly increase our knowledge of miRNAs in amphibians. A small RNA library was constructed from B. yenyuanensis and sequenced using deep sequencing. As a result, 1,717,751 clean reads were obtained, representing 356 known and 80 novel miRNAs. Additionally, expression levels of eight randomly selected miRNAs in B. yenyuanensis were confirmed using the stem-loop quantitative real-time reverse transcription PCR. In addition, 13,972 targets were predicted for these identified miRNAs, although the physiological functions of many of these targets remain unknown. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis suggested that the predicted targets are involved in a variety of physiological regulatory functions in B. yenyuanensis. These results provide useful information for further research on the miRNAs involved in the growth and development of B. yenyuanensis, as well as adaptation of this species to its high-altitude habitats.

The effect of CYP2C19 gene polymorphisms on the pharmacokinetics and pharmacodynamics of prasugrel 5-mg, prasugrel 10-mg and clopidogrel 75-mg in patients with coronary artery disease.

CYP2C19 genotype has been shown to impact response to clopidogrel 75-mg but not prasugrel 10-mg. Here, we assessed effects of CYP2C19 metaboliser status on pharmacokinetics (PK) and pharmacodynamic (PD) responses to prasugrel 5-mg and 10-mg and clopidogrel 75-mg using data from two PK/PD studies in stable coronary artery disease (CAD) patients (GENERATIONS and FEATHER). Active metabolite concentrations (area under the curve, AUC[0-tlast]), maximum platelet aggregation (MPA) measured by light transmission aggregometry, vasodilator-stimulated phosphoprotein platelet reactivity index, and VerifyNow P2Y12-platelet reaction units (VN-PRU) were analysed by CYP2C19-predicted phenotype (extensive metaboliser [EM; N=154], *2-*8 non-carriers, vs reduced metaboliser [RM; N=41],*2-*8 carriers/*17 non-carriers). AUC(0-tlast) was unaffected by metaboliser status for prasugrel 5-mg and 10-mg (geometric mean EM/RM ratios 1.00, 95% confidence interval [CI]: 0.86,1.17, p>0.99; and 0.97, 95% CI:0.85,1.12, p=0.71, respectively), but was lower among RMs receiving clopidogrel 75-mg (1.37, 95% CI:1.14,1.65, p<0.001). Platelet reactivity was not significantly affected by CYP2C19 metaboliser status for prasugrel 5-mg, or for prasugrel 10-mg by MPA and VN-PRU, but for clopidogrel 75-mg was significantly higher in reduced metabolisers (all measures p<0.01). Prasugrel 10-mg showed greater antiplatelet effects vs clopidogrel 75-mg (all comparisons p<0.001). Prasugrel 5-mg showed greater antiplatelet effects vs clopidogrel 75-mg in RMs (all p<0.001), and comparable effects in EMs (all p≥0.37). In contrast to clopidogrel, prasugrel active metabolite PK was not influenced by CYP2C19 genotype. Antiplatelet effect for prasugrel 10-mg was greater irrespective of metaboliser status and for prasugrel 5-mg was greater for RMs and comparable for EMs as compared to clopidogrel 75-mg.

Dietary conjugated linoleic acids and lipid source alter fatty acid composition of juvenile yellow perch, Perca flavescens.

A study was conducted to examine the effects of dietary conjugated linoleic acids (CLA; 0, 0.5 or 1.0 g/100 g total CLA) and lipid source (menhaden oil, soybean oil or a 1:1 mixture of menhaden:soybean oil) on growth rates and fatty acid composition of yellow perch. Dietary treatments were fed to apparent satiation to triplicate groups of fish initially weighing 37.9 g/fish. At the end of the 9-wk feeding trial, no significant differences were detected in weight gain or feed intake among fish fed any of the dietary treatments. Dietary CLA, lipid source and/or their interaction significantly affected feed efficiency, total liver lipid concentration, and muscle and liver fatty acid concentrations. Feed efficiency (g gain/g feed) was significantly lower in fish fed diets containing soybean oil (0.51) compared with fish fed menhaden oil (0.58) or menhaden:soybean oil (0.60). Liver total lipid concentrations were significantly reduced in fish fed 0.5 and 1.0 g/100 g CLA compared with fish fed the diets containing no CLA and in fish fed menhaden oil compared with those fed soybean oil or a 1:1 mixture of menhaden:soybean oil. Total CLA levels increased in both liver and muscle as dietary CLA concentration increased, irrespective of lipid source. However, total CLA concentrations were significantly lower in liver and muscle of fish fed soybean oil. Total muscle CLA concentrations were 0, 1.26 and 2.92 g/100 g fatty acids in fish fed diets containing menhaden oil and 0, 0.5 and 1.0 g/100 g CLA, respectively. Mono- and polyunsaturated fatty acid (PUFA) concentrations were significantly lower in muscle and liver of fish fed CLA compared with fish fed the diets containing no CLA. In contrast, liver concentrations of saturated fatty acids, 14:0, 16:0 and 18:0, were significantly higher in fish fed 1.0 g/100 g CLA.

Effects of dietary conjugated linoleic acids on hepatic and muscle lipids in hybrid striped bass.

Conjugated linoleic acids (CLA) are the focus of numerous studies, yet the effects of these isomers of octadecadienoic acids have not been evaluated in many species of fish. In this study, graded amounts of CLA--0, 0.5, 0.75, or 1.0% of the diet--were fed to juvenile hybrid striped bass for 8 wk. Dietary treatments were fed to apparent satiation twice daily to triplicate groups of fish initially weighing 13.4 g/fish. Feed intake and weight gain of fish fed 1.0% CLA were significantly reduced compared to fish fed no CLA. Fish fed 0.5 and 0.75% CLA exhibited reduced feed intake similar to fish fed 1.0% CLA, but had growth rates that were not significantly different from those of fish fed no CLA. Feed efficiency improved significantly in fish as dietary CLA concentrations increased. Total liver lipid concentrations were significantly reduced in fish fed the diets containing CLA compared to those of fish fed the control diet, and intraperitoneal fat ratio was significantly lower in fish fed 1.0% CLA compared to fish fed no CLA. Fish fed dietary CLA exhibited significant increases in hepatosomatic index and moisture content of muscle and carcass. The CLA isomers were detected in liver and muscle of fish fed the diets containing CLA, while a low concentration of one isomer was detected in liver and muscle of fish fed the control diet. Dietary CLA resulted in a significant increase in 18:2(c-9,c-12) concentration in liver and muscle, but a significant reduction in 18:1n-7 in these tissues. Furthermore, feeding CLA resulted in a significant increase in the concentration of 20:5n-3 and 22:6n-3 in liver, but a reduction of these fatty acids in muscle. This study showed that feeding CLA elevated tissue concentrations of these fatty acid isomers, reduced tissue lipid contents, improved feed efficiency, and altered fatty acid concentrations in liver and muscle of fish.

Choline is required by tilapia when methionine is not in excess.

Choline is essential in diets fed to most young vertebrates, but previous studies did not confirm the essentiality of choline in diets fed to tilapia. Two experiments were conducted to evaluate the essentiality of dietary choline in such diets. The basal diet used in both experiments contained 32 g crude protein/100 g diet (10.1 g crude protein from casein and gelatin, and 21.9 g from a crystalline L-amino acid mixture). The total sulfur amino acid (TSAA) concentration of the basal diet was 0.28 g/100 g diet, Met:Cys 89:11. In Experiment 1, a 4x2 design was used in which crystalline L-methionine was added to the basal diet resulting in four levels of TSAA (0.28, 0.50, 0.75 or 1.0 g/100 g diet, Met:Cys 89:11, 94:6, 96:4, or 97:3, respectively). At each level of TSAA, diets also contained either 0 or 1 g choline/kg diet supplied as choline chloride. Weight gain, feed efficiency (FE) and serum methionine concentrations were significantly affected by dietary TSAA concentration, but not by dietary choline concentration or the interaction between TSAA and choline. Weight gain, feed efficiency and serum methionine concentrations indicated that the TSAA requirement was 0.5 g/100 g diet. In the second experiment, diets were formulated to contain either 0.28 or 0.5 g TSAA/100 g diet, Met:Cys 89:11 or 94:6, respectively, and graded levels of choline ranging from 1 to 4 g/kg diet in gradations of 1 g/kg. Dietary methionine significantly affected weight gain and FE, whereas dietary choline significantly affected weight gain, FE and survival, and the interaction of methionine and choline significantly affected weight gain. Fish fed diets containing 0.5 g TSAA/100 g diet and 3 g choline chloride/kg diet exhibited the highest weight gain, feed efficiency and survival. On the basis of these data, it seems clear that juvenile tilapia require choline in certain dietary formulations.

Dietary sulfur amino acid requirement of juvenile yellow perch fed the maximum cystine replacement value for methionine.

We conducted three separate experiments designed to determine the dietary methionine requirement, ability of cyst(e)ine to spare methionine, and the total sulfur amino acid requirement (TSAA) of juvenile yellow perch when fed the maximal amount of cyst(e)ine. The purified basal diet used in each experiment contained 33.6 g of crude protein/100 g diet and 12.0 g of lipid/100 g diet. In the first experiment,;>L-methionine was added to eight diets providing methionine concentrations ranging from 0.37 to 1.77 g/100 g diet in gradations of 0.2 g/100 g diet. Diets were fed for 12 wk to juvenile yellow perch initially weighing 4.7 g/fish. Broken-line analyses of weight gain and feed efficiency data indicated that the dietary methionine requirement was 1.0 g/100 g diet (3.1 g TSAA/100 g dietary protein) and 1.1 g/100 g diet (3.4 g TSAA/100 g dietary protein), respectively. In the second experiment, various ratios of L-cyst(e)ine and L-methionine were added to the basal diet and fed for 12 wk to determine the cyst(e)ine replacement value of yellow perch initially weighing 19.3 g/fish. Weight gain and feed efficiency (FE) data indicated that cyst(e)ine spared up to 51% of the methionine requirement. In the final experiment, graded levels of cyst(e)ine plus methionine in a ratio of 51:49 were added to the basal diet in gradations of 0.1 g/100 g diet (0.5 to 1.2 g TSAA/100 g diet) to determine the dietary total sulfur amino acid requirement. Diets were fed to satiation for 10 wk to fish initially weighing 8. 1 g. Broken-line analyses of weight gain, feed intake and FE data indicated that the dietary TSAA requirement was 0.85, 0.87 and 1.0 g of TSAA/100 g diet (2.5 to 3.0 g of TSAA/100 g of dietary protein), respectively. The majority of dietary TSAA requirements of fish are in the range of 2 to 4 g/100 g of dietary protein and are generally similar to those of both birds and swine, but lower than estimates for rodents.

Spatial convergence and divergence between cutaneous afferent axons and dorsal horn cells are not constant.

We have proposed a quantitative model of the development of dorsal horn cell receptive fields (RFs) and somatotopic organization (Brown et al. [1997] Somatosens. Motor Res. 14:93-106). One component of that model is a hypothesis that convergence and divergence of connections between low-threshold primary afferent mechanoreceptive axons and dorsal horn cells are invariant over skin location and dorsal horn location. The more limited, and more easily tested, hypothesis that spatial convergence and divergence between cutaneous mechanoreceptors and dorsal horn cell are constant was examined. Spatial divergence is the number of dorsal horn cells whose RFs overlap the RF center of a primary afferent, and spatial convergence is the number of afferent RF centers that lie within the RF of a dorsal horn cell. Innervation density was determined as a function of location on the hindlimb by using peripheral nerve recording and axon counting. A descriptive model of dorsal horn cell receptive fields (Brown et al. [1998] J. Neurophysiol. 31:833-848) was used to simulate RFs of the entire dorsal horn cell population in order to estimate RF area and map scale as a function of location on the hindlimb. Previously reported correlations among innervation density, map scale, and RF size were confirmed. However, these correlations were not linear. The hypothesis that spatial convergence and divergence are constant was rejected. The previously proposed model of development of dorsal horn cell somatotopy and RF geometries must be revised to take variable spatial convergence and divergence into account.

Dietary choline requirement of juvenile yellow perch (Perca flavescens).

We conducted an 11-wk feeding trial to determine the dietary choline requirement of juvenile yellow perch (Perca flavescens) and to investigate whether dietary phosphatidylcholine (PC) could meet this requirement. Six dietary treatments contained choline concentrations of <0.11, 0.23, 0.34, 0.75, 1.22 or 3.37 g/kg diet. Two additional diets contained 31 g of lecithin/kg diet, with or without supplemental choline chloride (4.0 g choline/kg diet). The total sulfur amino acid concentration was maintained at 1.0 g/100 g diet (methionine/cyst(e)ine, 49:51). Diets were fed to satiation twice daily to triplicate groups of yellow perch initially weighing 16.0 g/fish. Weight gain, feed intake and carcass proximate composition were significantly affected by dietary choline. Weight gains and feed intakes increased as dietary choline increased from 0 to 0.75 g/kg. Both values tended to plateau in fish fed dietary choline levels above 0.75 g/kg. Broken-line analyses of weight gain and feed intake data indicated the dietary choline requirement was 0.598 and 0.634 g/kg diet, respectively. Hepatic lipid concentrations and feed efficiency values were not significantly different. Whole-body fat concentrations increased significantly, whereas ash levels decreased significantly in fish fed increasing levels of dietary choline. Weight gain and feed intake of fish fed diets containing PC were not significantly different from fish fed 0.75 g/kg of dietary choline. However, hepatic lipid concentrations were significantly higher in fish fed the diet containing PC and no choline chloride. Thus, yellow perch require a maximum of 0.598-0.634 g of choline/kg diet for maximum growth and this requirement may potentially be met with 31 g of lecithin/kg diet.

Dorsal horn spatial representation of simple cutaneous stimuli.

A model of lamina III-IV dorsal horn cell receptive fields (RFs) has been developed to visualize the spatial patterns of cells activated by light touch stimuli. Low-threshold mechanoreceptive fields (RFs) of 551 dorsal horn neurons recorded in anesthetized cats were characterized by location of RF center in cylindrical coordinates, area, length/width ratio, and orientation of long axis. Best-fitting ellipses overlapped actual RFs by 90%. Exponentially smoothed mean and variance surfaces were estimated for these five variables, on a grid of 40 points mediolaterally by 20/segment rostrocaudally in dorsal horn segments L4-S1. The variations of model RF location, area, and length/width ratio with map location were all similar to previous observations. When elliptical RFs were simulated at the locations of the original cells, the RFs of real and simulated cells overlapped by 64%. The densities of cell representations of skin points on the hindlimb were represented as pseudocolor contour plots on dorsal view maps, and segmental representations were plotted on the standard views of the leg. Overlap of modeled and real segmental representations was at the 84% level. Simulated and observed RFs had similar relations between area and length/width ratio and location on the hindlimb: r(A) = 0.52; r(L/W) = 0.56. Although the representation of simple stimuli was orderly, and there was clearly only one somatotopic map of the skin, the representation of a single point often was not a single cluster of active neurons. When two-point stimuli were simulated, there usually was no fractionation of response zones or addition of new zones. Variation of stimulus size (area of skin contacted) produced less variation of representation size (number of cells responding) than movement of stimuli from one location to another. We conclude that stimulus features are preserved poorly in their dorsal horn spatial representation and that discrimination mechanisms that depend on detection of such features in the spatial representation would be unreliable.

Visualization of significant differences in somatotopic maps: a distributed t-test.

In order to test for differences in the properties of two populations of cells within a somatotopic map we need to be able to compare data sets in which sampled cells are randomly scattered throughout the map, and the variable being compared varies with location in the map. We can describe cell properties as exponentially smoothed surfaces fitted to data in the plane of the map, where all data contribute to the computation of the value of each grid point on the surface, with weights which decline exponentially with distance from the grid point. Means, variances and Student's t values can be computed at all grid points, keeping in mind the fact that grid points' t values are not independent of each other. We used Monte Carlo methods to demonstrate that two random samples of 500 values from two populations of 100,000 values at 4000 grid can provide a very useful picture of regions with significant differences. We recommended this procedure, or analogous approaches using other statistical tests, for any analysis where it is necessary to compare values of dependent variables when matched locations on the independent axis or plane cannot be sampled in the two populations.

Dietary arginine requirement of juvenile yellow perch.

We conducted an 8-wk feeding experiment to determine the dietary arginine requirement of juvenile yellow perch (Perca flavescens). The basal diet contained 33 g crude protein/100 g diet (23 g crude protein supplied by crystalline L-amino acids and 10 g crude protein supplied by casein and gelatin). Eight dietary treatments contained graded levels of L-arginine-HCl ranging from 0.44 to 1.84 g/100 g dry diet in gradations of 0.2 g/100 g diet. Diets were made isonitrogenous with L-glutamic acid and were fed to triplicate groups of fish with an initial weight of 11 g/fish. Dietary arginine significantly affected weight gain and feed efficiency but not survival. The best weight gain and feed efficiency values were 155. 3% increase from initial weight and 0.63, respectively. Quadratic regression analyses of weight gain and feed efficiency data indicated the dietary arginine requirement to be 1.61 and 1.41 g/100 g diet, respectively. We recommend 1.41 g L-arginine-HCl/100 g diet for juvenile yellow perch fed purified diets. The recently developed dietary arginine requirements of fish are surprisingly similar and generally higher than those of the ureotelic mammals and lower than the uricotelic birds.

Correlation of peripheral innervation density and dorsal horn map scale.

Dorsal horn map scale and peripheral innervation density were compared to test a hypothesized linear relationship. In anesthetized cats, low-threshold mechanoreceptive peripheral nerve innervation fields (IFs) were measured by outlining areas of skin from which action potentials could be elicited in cutaneous nerves. The same nerves were processed histologically and used to count myelinated axons. Innervation density for each nerve was calculated as number of axons divided by IF area. Single units were recorded throughout the hindlimb representation, in laminae III and IV. These data, combined with single-unit data from other animals and with cell counts in laminae III and IV, permitted estimation of numbers of cells whose receptive field centers fell in contiguous 1-cm bands from tips of toes to proximal thigh. A similar estimate was performed with the use of the nerve innervation data, so that peripheral innervation densities and map scales for the different 1-cm bands of skin could be compared. Correlation between the two was quite high (r = 0.8), and highly significant (P = 2.5 x 10(-7)). These results are consistent with a proposed developmental model in which map scale, peripheral innervation density, and reciprocal of dorsal horn cell receptive field size are mutually proportional, as a result of developmental mechanisms that produce constant divergence and convergence between primary afferent axons and dorsal horn cells.

Assembly of the dorsal horn somatotopic map.

We hypothesize: (a) peripheral innervation densities determine map scales in dorsal horn, (b) dorsal horn cell (DHC) receptive field (RF) geometries are determined by map scales, and (c) morphologies of primary afferents (PAs) and DHCs reflect their developmental history. We suggest the following sequence: (A) PAs project in a somatotopic mediolateral sequence. (B) DHCs assemble prototype RFs by sampling presynaptic neuropil with their dendrites. (C) PAs then project to all levels where their RFs are contained within prototype RFs of DHCs. (D) A competitive mechanism produces the adult form of DHC RFs. (E) Adult distributions of PA terminals and DHC dendrites reflect this developmental history. (F) Mediolateral somatotopic gradients are determined by RF densities of axons entering at the same levels. (G) Map scales at different rostrocaudal levels are determined by somatotopic gradients. (H) Geometries of DHC RFs are determined by constant convergence and divergence of monosynaptic connections. (I) Secondary processes further modify geometries of DHC RFs. (J) Residual self-organizing capacity supports maintenance and plastic mechanisms. We adduce the following evidence: (1) agreement between monosynaptically coupled inputs and cells' excitatory low threshold mechanoreceptive fields; (2) the temporal sequence of events during penetration of the gray matter by PAs; (3)variation of PA terminal and DHC dendritic domains as a function of map scale; (4) somatotopic gradients and geometries of DHC RFs in adult dorsal horn; (5) calculations of peripheral innervation densities and dorsal horn map scales; and (6) constant divergence and convergence between PAs and DHCs.

Pulsatile lower limb venous Doppler flow: prevalence and value in cardiac disease diagnosis.

The purpose of this study was to assess the frequency and significance of pulsatile Doppler waveforms in lower limb veins. We used Doppler sonographic data from the common femoral vein. In the first of two groups, the findings in 250 patients were correlated with the presence of cardiac decompensation on concurrent chest radiographs. In the second group, the findings in 81 patients were correlated with the presence of tricuspid regurgitation on Doppler echocardiograms. A venous Doppler sonographic examination was considered normal if spontaneous anterograde phasic flow was present and pulsatile if flow had a cyclic retrograde component. In group 1, 21% had pulsatile waveforms whereas 24% had cardiac decompensation. In group 2, 36% had pulsatile waveforms and 43% had tricuspid regurgitation. A statistically significant correlation was found between the presence of these abnormal waveforms and cardiac decompensation or tricuspid regurgitation, with sensitivities of 57% and 54%, specificities of 91% and 78%, positive predictive values of 66% and 66%, negative predictive values of 87% and 69%, and accuracies of 82% and 68%, respectively. In a subgroup of 55 patients who had both tests for correlation and in whom both were in agreement, the sensitivity of venous Doppler sonographic examination for detecting pathologic cardiac conditions was 79%, specificity was 87%, positive predictive value was 83%, negative predictive value was 84%, and accuracy was 84%. In 77 patients with pulsatile waveforms, including 24 without concurrent chest radiographs or echocardiograms, 63 (82%) had no prior history of cardiac disease. When correlated separately with chest radiograph or Doppler echocardiography, the test is not very sensitive in the diagnosis of cardiac disease; however, when both correlating tests are performed and are in agreement, all diagnostic parameters of the venous Doppler sonographic test, including sensitivity, become fairly high. The presence of pulsatile lower limb venous Doppler flow should alert the sonologist that a pathologic cardiac condition may be the culprit, especially in patients who have no such prior diagnosis.

Variation of dorsal horn cell dendritic spread with map scale.

Cells in laminae III, IV, and V of cat dorsal horn were injected with horseradish peroxidase or neurobiotin. Dorsal views of the dendritic domains were constructed in order to measure their lengths, widths, areas, and length/width ratios in the horizontal plane (the plane of the somatotopic map). Dendritic domain width and area in the horizontal plane were negatively correlated with fractional distance between the medial and lateral edges of the dorsal horn. These results are consistent with the hypothesis that dendritic domain width varies with map scale, which is maximal in the medial dorsal horn. This is similar to the variation in widths of primary afferent bouton distributions. The parallel variation of dorsal horn cell dendritic domain width and primary afferent bouton distribution width with map scale suggests that there is a causal relation between morphology and map scale in the dorsal horn representation of the hindlimb. This variation of adult morphology with map scale must reflect mechanisms responsible for the assembly of receptive fields.

Quantitative analysis of dorsal horn cell receptive fields following limited deafferentation.

1. To test the hypothesis that subtotal deafferentation of dorsal horn cells can stimulate plastic changes in their receptive fields (RFs), diffuse deafferentation of the cat hindlimb dorsal horn was produced by transection of L7 or L6 and L7 dorsal roots. The following single-unit cutaneous low-threshold mechanoreceptor RF properties were compared between operated and control dorsal horns: 1) distance of RF center from tips of toes, 2) RF length-width ratio; and 3) RF area. 2. In both L7 and L6-L7 rhizotomized animals there was an increased incidence of silent electrode tracks in the most deafferented portion of the hindlimb map (the foot and toe representation). In the rhizotomized L6-L7 animals, there was also an increased incidence of symmetrically placed tracks in deafferented and control dorsal horns, in which cell RFs had no mirror-symmetrical components. In addition, cells in the lateral half of the L6 and L7 dorsal horns exhibited a proximal shift in the location of their RFs. In the rhizotomized L7 animals there was a distal shift of RFs in the L5 segment at long survival times. RFs had lower length-width ratios in L5 and L6 at short survival times and in L6 at long survival times. 3. In intact preparations, dorsal horn cells normally respond to inputs via single or small numbers of low-threshold cutaneous mechanoreceptors. Because these rhizotomies do not remove all inputs from any given area of skin, the deafferentations would produce only patchy loss of input from individual receptors. Therefore observed changes cannot be accounted for entirely by loss of afferent input, suggesting that some reorganization of dorsal horn cell RFs occurred. We conclude that the threshold stimulus for plastic change is less than total deafferentation of dorsal horn cells. At least some of the mechanisms underlying these changes may be active in normal animals in the maintenance of the somatotopic map or in conditioning.

Maintenance of adequate hemodialysis access. Prevention of neointimal hyperplasia.

The maintenance of adequate hemodialysis vascular access is frequently complicated in the patient with polytetrafluoroethylene (PTFE) A-V hemodialysis grafts by venous anastomotic stenosis. This stenosis is caused by neointimal hyperplasia (NIH), a response to vascular injury. In this study, the authors prospectively analyzed the effect of a short-term regimen consisting of administration of two medications, heparin and low molecular weight dextran, on the development of NIH at the venous anastomosis in 79 patients with PTFE A-V hemodialysis grafts. In addition, they evaluated other parameters' effects on the development of NIH. In comparison with control subjects, heparin had some effect in minimizing the development of NIH in the PTFE grafts when evaluated radiologically at 3 months, although this effect was not statistically significant. Low molecular weight dextran, however, had no trend or statistically significant effect on this venous anastomotic narrowing. Interestingly, patient age, use of calcium channel blockers, and presence of diabetes mellitus (DM) all appeared to affect the development of NIH. Increasing age and use of calcium channel blockers was associated with decreased development of NIH; conversely, DM was associated with worsened NIH. In evaluation of access survival (time to first access failure), degree of venous anastomosis stenosis at 3 months was not predictive. Patient time on dialysis pre graft placement was the only measured parameter related to access failure. The method of dialysis pre graft placement (hemodialysis versus peritoneal dialysis) was not a significant factor in early access failure. Pharmacologic treatment of venous anastomotic narrowing in PTFE hemodialysis grafts due to NIH continues to be difficult. Short-term treatment with the tested medication failed to statistically affect NIH. Patient age, use of calcium channel blockers, and presence of DM were all factors in the development of NIH. Of measured parameters, time on dialysis pre graft placement was the only factor correlated with early access failure. In future treatment regimens, one should consider more prolonged treatment. In addition, noted risk factors should be considered when determining type of renal replacement therapy.

Comparison of diagnostic accuracy with carbon dioxide versus iodinated contrast material in the imaging of hemodialysis access fistulas.

PURPOSE: Imaging of dialysis fistulas was performed with use of carbon dioxide and iodinated contrast material. Images were then compared to assess the quality and accuracy of CO2 as a contrast agent. PATIENTS AND METHODS: Thirty-two patients underwent digital subtraction imaging of the fistulas performed with both iodinated contrast material and CO2 to evaluate the venous anastomosis. The images were blinded and the degree of stenosis was graded in 10% increments by two physicians. Statistical analysis including sensitivity, specificity, and accuracy of CO2 images was performed. RESULTS: There was no significant difference in physician ratings of the degree of venous stenosis (P > .30). Estimation of the degree of stenosis was significantly higher with CO2 than with ionic contrast material (P = .0001). When iodinated contrast material is used as the gold standard, the sensitivity, specificity, and accuracy of CO2 were 94%, 58%, and 75%, respectively. CONCLUSIONS: CO2 has a role as a contrast agent in the imaging of dialysis access grafts when the use of iodinated contrast material is of concern. CO2 is safe for venous injections; however, it should not be used to evaluate the arterial anastomosis with the "reflux technique."

Dietary choline requirement of juvenile hybrid striped bass.

Two experiments were conducted to estimate the dietary choline requirement and to determine the effects of dietary choline on liver lipid deposition in juvenile hybrid striped bass (Monrone saxatilis x M. chrysops). Experimental diets contained 0.73 g total sulfur amino acids/100 g diet (0.47 g methionine + 0.26 g cyst(e)ine/100 g diet), thus meeting, but not exceeding, the requirement. Graded levels of choline bitartrate in Experiment 1 and choline chloride in Experiment 2 were added to the basal diet, resulting in eight dietary treatments in each experiment. Dietary treatments were 0, 250, 500, 1000, 2000, 4000, 6000 and 8000 mg choline/kg dry diet. Diets were fed for 12 and 10 wk in Experiments 1 and 2, respectively. Dietary choline concentrations significantly affected weight gain, feed efficiency, survival and total liver lipid concentrations in each experiment. Weight gain and feed efficiency were greatest in fish fed 500 mg choline/kg dry diet as choline bitartrate. Total liver lipid concentrations were variable but tended to be lowest in fish fed diets containing at least 2000 mg choline/kg diet. Survival was significantly lower in the group of fish fed 8000 mg choline/kg diet supplied by choline bitartrate. Weight gain and feed efficiency were greatest and total liver lipid concentration was lowest in groups of fish fed at least 500 mg choline/kg diet as choline chloride; survival was unaffected by dietary treatment. Therefore, choline chloride seems to be a better source of dietary choline than choline bitartrate and 500 mg choline/kg diet is adequate for maximum weight gain and prevention of increased liver lipid concentration in juvenile hybrid striped bass.

Central sprouting and functional plasticity of regenerated primary afferents.

A combination of neuroanatomical and electrophysiological techniques was used to study the effects of peripheral axotomy and regeneration of primary afferents on their central projections in the spinal cord. Individual regenerated afferent fibers were impaled with HRP-filled electrodes in the dorsal columns of alpha-chloralose-anesthetized cats and activated by current pulses delivered via the intracellular electrode. The resulting cord dorsum potentials (CDPs) were recorded at four rostrocaudal locations and HRP was iontophoretically injected into the fiber. Central distributions of boutons and CDPs were compared with peripheral receptor type to determine the accuracy of peripheral regeneration and the effects of central-peripheral mismatches. Reconstruction of the central projections of 13 individual afferents for which the adequate stimulus and CDPs had been recorded revealed many abnormalities. For example, unlike controls, four group I and II afferents with central projections typical of proprioceptors (concentrated in laminae V, VI, and VII) innervating either cutaneous or noncutaneous targets evoked measurable CDPs. Three other group II or A beta afferents innervating low-threshold mechanoreceptors with central terminations confined to the dorsal horn exhibited extensive collateralization in laminae I and II in addition to large numbers of terminals in laminae III-IV. These fibers activated central networks whose adaptation behavior was identical to those evoked by high-threshold mechanoreceptive afferents in controls. These results suggest that primary afferents and their central connections are capable of significant modifications following axotomy and regeneration. In addition, the anatomical studies indicate some reorganization in the laminar distribution of boutons as well as in bouton size.