Vowel production in children using cochlear implants.
Explore the source record for details and available documents.
Case-Control Studies↗
Biomedical subjects
J A Moore
Publications and source records attributed to J A Moore.
8 french transradial coronary interventions: clinical outcome and late effects on the radial artery and hand function.
BACKGROUND: Limited information is available on the effects of 8 French (Fr) transradial procedures on radial patency. In addition, the effects of radial procedures and radial occlusion on hand function are unknown. METHODS: Two groups were recruited: twenty-four patients who had undergone 26 transradial 8 Fr interventions and 16 patients who had undergone 16 transradial 6 Fr procedures. At 1 year, radial patency, hand strength and hand endurance were measured. RESULTS: No major adverse cardiac events or vascular complications were noted in either group. Late radial occlusion was noted in 2/18 (11%) 8 Fr patients and 3/16 (19%) 6 Fr patients (p = ns). There were no differences in the 8 Fr group between the catheterized and uncatheterized radial arteries for diameter (3.2 +/- 1.1 mm versus 3.3 +/- 0.7 mm, respectively; p = NS) or volumetric flow (55 +/- 51 ml/minute versus 57 +/- 45 ml/minute, respectively; p = NS). No differences in hand strength or hand endurance were seen between the catheterized and uncatheterized arms in the 8 Fr group, between the 8 Fr and 6 Fr groups, or between occluded and non-occluded patients. CONCLUSION: Transradial use of 8 Fr guiding catheters appears to be feasible and safe in highly selected patients, albeit associated with a low incidence of silent radial occlusion. Additionally, neither the use of 8 Fr sheaths nor the presence of radial artery occlusion appear to adversely affect hand strength or endurance.
Aged↗
Synthesis of a chemiluminescent acridinium hydroxylamine (AHA) for the direct detection of abasic sites in DNA.
[structure: see text] The synthesis of a chemiluminescent acridinium hydroxylamine (AHA) for the direct detection of abasic sites in damaged nucleic acids is described. The reagent reacts readily with abasic sites of damaged calf thymus DNA generated in a time-dependent manner under acid/heat depurination conditions. Preliminary results indicate the sensitivity of the direct chemiluminescent detection format is approximately 0.1 abasic sites detected per 10(6) nucleotides using as little as 200 ng of DNA.
Acridines↗
Investigations into self-association of vancomycin covalent dimers using surface plasmon resonance technology.
Covalent dimers of vancomycin linked through the vancosamine sugar moieties of the glycopeptide antibiotic have been synthesized in one step in 67-69% yield. The propensity for self-association of these and related vancomycin covalent dimers is evaluated using surface plasmon resonance technology.
Anti-Bacterial Agents↗
Teratology Society Public Affairs Committee position paper: developmental toxicity of endocrine disruptors to humans.
Explore the source record for details and available documents.
Abnormalities, Drug-Induced↗
Effect of transradial access on quality of life and cost of cardiac catheterization: A randomized comparison.
BACKGROUND: Transradial access is a recently developed alternative for diagnostic cardiac catheterization. Its effects on quality of life after the procedure, patient preference, and cost are unknown. METHODS AND RESULTS: We performed a randomized single-center trial in which 99 patients underwent transfemoral and 101 underwent transradial diagnostic cardiac catheterization. Quality of life was measured with the SF-36 and visual analog scales at baseline, 1 day, and 1 week. Patients were examined at 1 day and at 1 week after for complications. Costs were measured prospectively. One patient in the femoral group and 2 in the radial group crossed over to the alternative access site. There were no major access site complications. One patient in the transfemoral group had a minor stroke. Transradial catheterization significantly reduced median length of stay (3.6 vs 10.4 hours, P <.0001). Over the first day after the procedure, measures of bodily pain, back pain, and walking ability favored the transradial group (P <.05 for all comparisons). Over the week after the procedure, changes in role limitations caused by physical health, bodily pain, and back pain favored the transradial group (P <.05 for all comparisons). There was a strong patient preference for transradial catheterization as well (P <. 0001). Transradial catheterization led to significant reductions in bed, pharmacy, and total hospital costs ($2010 vs $2299, P <.0001). CONCLUSIONS: Among patients undergoing diagnostic cardiac catheterization, transradial access leads to improved quality of life after the procedure, is strongly preferred by patients, and reduces hospital costs.
Cardiac Catheterization↗
Comparison of risk of conductive hearing loss among three ethnic groups of Arctic audiology patients.
The purpose of the study was to investigate the relative contributions of age, gender, ethnic background, and a history of middle ear disease on the amount of conductive hearing impairment among native and non-native audiology patients in the Canadian North. A second goal of the study was to determine risk factors for conductive hearing loss in the patients studied. Three ethnic groups were represented among the 3,094 patients: Inuit, American Indian, and non-native. Loglinear and logit statistical models were applied, and these data were best explained by a 3-way interaction of history of middle ear disease, ethnic group, and hearing loss, and the 2-way interaction of age and hearing loss. The Inuit appear to be at higher risk for conductive hearing impairment than the other ethnic groups. Conductive hearing loss also appears to increase as age increases through the teenage years for all the patients regardless of ethnic group membership. Preschoolers were at the lowest risk for conductive hearing loss. The trend for the amount of hearing impairment to increase throughout childhood suggests that children living in the Arctic may manifest a unique and more serious form of the disease not often observed in audiology patients who are Caucasian in southern Canada or the United States or that they may be exposed to additional risk factors.
Adult↗
A numerical study of blood flow patterns in anatomically realistic and simplified end-to-side anastomoses.
PURPOSE: Recently, some numerical and experimental studies of blood flow in large arteries have attempted to accurately replicate in vivo arterial geometries, while others have utilized simplified models. The objective of this study was to determine how much an anatomically realistic geometry can be simplified without the loss of significant hemodynamic information. METHOD: A human femoral-popliteal bypass graft was used to reconstruct an anatomically faithful finite element model of an end-to-side anastomosis. Nonideal geometric features of the model were removed in sequential steps to produce a series of successively simplified models. Blood flow patterns were numerically computed for each geometry, and the flow and wall shear stress fields were analyzed to determine the significance of each level of geometric simplification. RESULTS: The removal of small local surface features and out-of-plane curvature did not significantly change the flow and wall shear stress distributions in the end-to-side anastomosis. Local changes in arterial caliber played a more significant role, depending upon the location and extent of the change. The graft-to-host artery diameter ratio was found to be a strong determinant of wall shear stress patterns in regions that are typically associated with disease processes. CONCLUSIONS: For the specific case of an end-to-side anastomosis, simplified models provide sufficient information for comparing hemodynamics with qualitative or averaged disease locations, provided the "primary" geometric features are well replicated. The ratio of the graft-to-host artery diameter was shown to be the most important geometric feature. "Secondary" geometric features such as local arterial caliber changes, out-of-plane curvature, and small-scale surface topology are less important determinants of the wall shear stress patterns. However, if patient-specific disease information is available for the same arterial geometry, accurate replication of both primary and secondary geometric features is likely required.
Anastomosis, Surgical↗
Chitinases from uncultured marine microorganisms.
Our understanding of the degradation of organic matter will benefit from a greater appreciation for the genes encoding enzymes involved in the hydrolysis of biopolymers such as chitin, one of the most abundant polymers in nature. To isolate representative and abundant chitinase genes from uncultivated marine bacteria, we constructed libraries of genomic DNA isolated from coastal and estuarine waters. The libraries were screened for genes encoding proteins that hydrolyze a fluorogenic analogue of chitin, 4-methylumbelliferyl beta-D-N,N'-diacetylchitobioside (MUF-diNAG). The abundance of clones capable of MUF-diNAG hydrolysis was higher in the library constructed with DNA from the estuary than in that constructed with DNA from coastal waters, although the abundance of positive clones was also dependent on the method used to screen the library. Plaque assays revealed nine MUF-diNAG-positive clones of 75,000 screened for the estuarine sample and two clones of 750,000 for the coastal sample. A microtiter plate assay revealed approximately 1 positive clone for every 500 clones screened in the coastal library. The number of clones detected with the plaque assay was consistent with estimates of the portion of culturable bacteria that degrade chitin. Our results suggest that culture-dependent methods do not greatly underestimate the portion of marine bacterial communities capable of chitin degradation.
Bacteria↗
Flake density of steam-processed sorghum grain alters performance and sites of digestibility by growing-finishing steers.
The effect of several flake densities (FD) of steam-processed sorghum grain on performance, and site and extent of nutrient digestibilities by steers fed growing and finishing diets was determined. The effectiveness of common laboratory methods of starch availability (enzymatic hydrolysis or gelatinization) to provide target specifications for quality control of steam-flaked grains was also measured. In vitro starch availability of the processed grains increased (P < .05) linearly in response to decreased FD. Flake density was more highly correlated with enzymatic measures than with percentage gelatinization (R2 = .87 to .93 vs .36). Using 140 crossbred beef steers (181 kg initial weight), feedlot performance was determined for 112 d with a growing diet (50% grain), followed by 119 d with a finishing diet (78% grain). Each FD treatment (412, 360, 309, and 257 g/L or 32, 28, 24, and 20 lb/bu) was randomly assigned to five pens of seven steers each. Intake of DM by steers decreased linearly (P < .05) as FD decreased (7 and 13%, respectively, for growing and finishing diets). Decreasing FD reduced linearly (P < .05) ADG in the finishing phase and for the entire 231-d trial. With the growing diet only, feed efficiency and estimated diet NEm and NEg responses to decreasing FD were curvilinear (P < .05), with the 360 g/L (28 lb/bu) flake being most efficient. Electrical energy requirements for processing increased linearly (P < .05) as FD decreased. Using four multi-cannulated crossbred steers (275 kg), starch digestibility increased linearly (P < .05) in the rumen (82 to 91%) and total tract (98.2 to 99.2%) as FD decreased. Digestibilities within the small (74%) and large intestines (62%) were not altered by FD. Decreasing FD increased (P < .05) total CP digestibility, but did not consistently alter fiber digestibility or DE content of the diets. In conclusion, enzymatic laboratory methods to evaluate starch availability in processed grains can be used satisfactorily to establish FD criteria for quality control of the steam-flaking process. The greatest improvements in efficiency, estimated diet NE, and starch and protein digestibilities usually occurred when FD was decreased from 412 to 360 g/L (32 to 28 lb/bu). Based on these measures and processing costs, the optimal FD was 360 g/L (28 lb/bu).
Animal Feed↗
O-(fluoresceinylmethyl)hydroxylamine (OFMHA): a fluorescent reagent for detection of damaged nucleic acids.
5- and 6-O-(Fluoresceinylmethyl)hydroxylamine (OFMHA, 5a, b) were prepared from the corresponding bis-pivaloyl-protected hydroxymethylfluoresceins (1a, b) in 50-70% yield. The hydroxylamine derivatives reacted smoothly with the abasic sites present in acid/heat stressed calf thymus DNA.
Animals↗
Structural characteristics of low-molecular-mass displacers for cation-exchange chromatography. II. Role of the stationary phase.
The relative efficacy of a variety of low-molecular-mass displacers was examined on three different stationary phase materials. Several homologous series of displacer molecules were evaluated on these ion-exchange resins using a displacer ranking plot based on the steric mass action model. The results demonstrate that while aromaticity and hydrophobicity can play a significant role in the affinity of displacer molecules on polymethacrylate based and hydrophilized polystyrene-divinylbenzene based materials, this effect is much less pronounced on an agarose based resin. The work presented in this paper demonstrates that different structural features of low-molecular-mass displacers can dominate their affinity on various stationary phase materials employed and provides rules of thumb for the design of high affinity, low-molecular-mass displacers for a variety of commercial cation-exchange materials.
Cation Exchange Resins↗
Structural characteristics of low-molecular-mass displacers for cation-exchange chromatography.
The relative efficacy of a variety of low-molecular-mass displacers was examined using a displacer ranking plot. This method enables an evaluation of the dynamic affinity of a variety of displacers over a range of operating conditions. Several homologous series of molecules were evaluated to provide insight into the effects of various structural features on displacer efficacy. The results indicate that linear flexible geometries may have advantages over branched or cyclic structures. Data also indicate that the spreading out of charges may increase affinity. The incorporation of aromatic moieties in these displacers, particularly near the surface of the molecules, appears to result in a dramatic increase in displacer affinity. The ability of several high-affinity low-molecular-mass displacers a very strongly bound cationic protein is also examined. The results confirm the predictions of the theory and indicate that it is indeed possible to displace highly bound macromolecules with low-molecular-mass dispatchers. The work presented in this paper indicates that non-specific interactions can be exploited for producing high-affinity low-molecular-mass displacers.
Algorithms↗
Estradiol-mimetic probes. Preparation of 17 alpha-(6-aminohexynyl)estradiol biotin, fluorescein and acridinium conjugates.
3-O-tert-Butyldimethylsilyl-17 alpha-(6-mesyloxyhexynyl)estradiol was converted to the azide in 60-70% yield with NaN3/DMPU, then reduced to the corresponding amine (> 95% yield). Acylation with the N-hydroxysuccinimide esters of biotin, 5-carboxyfluorescein and 10-(3-sulfopropyl)-N-tosyl-N-(3- carboxypropyl)acridinium-9-carboxamide gave the title conjugates. The KDs of the tracers with an estradiol antibody ranged from 97-197 nM.
Acridines↗
The catalytic mechanism of kynureninase from Pseudomonas fluorescens: insights from the effects of pH and isotopic substitution on steady-state and pre-steady-state kinetics.
The effects of pH and isotopic substitution of substrate and solvent on the reaction of kynureninase from Pseudomonas fluorescens have been determined. The pH dependence of kcat/Km for L-kynurenine is bell-shaped, with apparent pKa's of 6.25 +/- 0.05 on the acidic limb and 8.9 +/- 0.1 on the basic limb, and with a pH-dependent value of kcat/Km of 2 x 10(5) M-1 s-1. The pH dependence of kcat/Km for 3-hydroxykynurenine is also bell-shaped, with apparent pKa's of 6.49 +/- 0.07 and 8.55 +/- 0.09, and with a pH-dependent value of 2.5 x 10(3) M-1 s-1. The kcat for L-kynurenine decreases at acidic pH values, with an apparent pKa of 6.43 +/- 0.06 and a pH-dependent value of 7 s-1. The solvent kinetic isotope effect on kcat for the reaction of kynurenine in [2H]H2O is 6.56 +/- 0.59, whereas there is no normal kinetic isotope effect on kcat/Km, at pH 8.1. The proton inventory of kcat fits very well to the Gross-Butler equation, with x = 0.825 +/- 0.08, suggesting that only a single proton is transferred in the rate-determining step. In contrast, there is no significant kinetic isotope effect on either kcat or kcat/Km with alpha-[2H]-L-kynurenine as the substrate. There is a "burst" of anthranilate (0.7 mol/mol of enzyme) formed in the pre steady state of the reaction of kynureninase, with a rate constant of 54 s-1 which is not affected by [2H]H2O. The partition ratio of alanine to pyruvate formation is 2.3 x 10(4) in H2O and 6.9 x 10(3) in [2H]H2O. Taken together, these data indicate that the rate-limiting step in the reaction of kynureninase occurs subsequent to the first irreversible step, which is anthranilate release, is general base catalyzed, and involves transfer of only a single proton. On the basis of these observations, we propose that the rate-limiting step in the reaction of kynureninase is C-4' deprotonation of the pyruvate pyridoxamine 5'-phosphate ketimine intermediate.
Catalysis↗
Comparative carcinogenicity in Sprague-Dawley rats of the polychlorinated biphenyl mixtures Aroclors 1016, 1242, 1254, and 1260.
A comprehensive chronic toxicity and carcinogenicity study was conducted on a series of Aroclors (1016, 1242, 1254, and 1260). Each Aroclor was assessed at multiple dietary concentrations, ranging from 25 to 200 ppm, for 24 months in male and female Sprague-Dawley rats. Liver toxicity was indicated by elevated serum enzyme activity (AST, ALT, and GGT), elevated serum cholesterol concentration, decreases in hematologic parameters (RBC, Hb, and Hct), hepatocellular hypertrophy, an increased incidence of altered hepatocellular foci, and an increased incidence of hepatocellular neoplasms (primarily adenomas). Liver toxicity was distinctly more severe in females than in males. The incidence of hepatocellular neoplasms was highly sex-dependent (females >> males), differed between Aroclor mixtures and, for females, increased with dose and followed the general incidence pattern of Aroclor 1254 > Aroclor 1260 approximately Aroclor 1242 > Aroclor 1016. A significant response (p < 0.05) in males was seen only for the high dose of Aroclor 1260. A small increase in the incidence of thyroid gland follicular cell adenomas was noted in males for Aroclors 1242, 1254, and 1260, with the incidence being uniform across dose groups and Aroclor mixtures. For females, increased survival relative to controls was observed for all Aroclor treatment groups. A significantly decreased trend in the incidence of mammary gland neoplasms compared to control was also noted for females receiving Aroclors 1242, 1254, and 1260.
Animals↗
Computational blood flow modelling: errors associated with reconstructing finite element models from magnetic resonance images.
Construction of computational blood flow models from magnetic resonance (MR) scans of real arteries is a powerful tool for studying arterial hemodynamics. In this report we experimentally determine a lower bound for errors associated with such an approach, and present techniques for minimizing such errors. A known, simple three-dimensional geometry (cylindrical tube) was imaged using a commercial MR scanner, and the resulting images were used to construct finite element flow models. Computed wall-shear stresses were compared to known values and peak errors of 40-60% were found. These errors can be attributed to limited spatial resolution, image segmentation and model construction. A simple smoothing technique markedly reduced these peak errors. We conclude that smoothing is required in the construction of arterial models from in vivo MR images. If used appropriately, such images can be used to construct acceptably accurate computational models of realistic arterial geometries.
Blood Circulation↗
Pseudoaneurysm of the ulnar artery occurring after fracture of the distal radius and ulna: a case report.
A case of pseudoaneurysm of the ulnar artery occurring after distal radius and ulna fracture is presented. This case illustrates an uncommon complication following a fairly common injury.
Accidental Falls↗