Povidone-iodine as a corrosion inhibitor towards a low modulus beta Ti-45Nb implant alloy in a simulated body fluid.

Povidone-iodine and various bactericidal agents used in dental procedures may affect the corrosion response of an implant/prosthesis in the oral environment. The effect of various concentrations of povidone-iodine (PI) on the corrosion behavior of a low modulus beta titanium alloy, Ti-45Nb, has been investigated in normal saline solution. The open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization measurements have been used to assess the electrochemical response of the alloy surface on PI addition so as to effectively predict the prosthetic treatment outcome. As the concentration of PI is increased, the corrosion rate decreases, suggested by decreased R(p) values. Povidone-iodine acts as an anodic inhibitor by adsorbing on the anodic sites of the alloy. Addition of PI to a simulated body fluid such as normal saline leads to a decrease in corrosion rate of Ti-45Nb alloy.

Cystinosis. Intracellular cystine depletion by aminothiols in vitro and in vivo.

Certain aminothiols rapidly deplete cultured cystinotic skin fibroblasts of their abnormally high free (nonprotein) cystine pool. The free cystine content of these cells if reduced by over 90% in 1 h with 0.1 mM cysteamine. This is more rapid than previously known methods of removing free cystine from cystinotic fibroblasts. The disulfide, cystamine, is also able to deplete cystinotic cells of free cystine. A patient with nephropathic cystinosis and end-stage renal disease was treated with cysteamine, both intravenously and orally. Both methods of administration rapidly lowered the free cystine content of the patient's peripheral leukocytes. Study of the patient's urinary sulfur excretion did not conclusively determine the effect of this therapy on the total body cystine pool. Her renal status remained at end stage after 1 mo of oral cysteamine, when an episode of grand mal seizures prompted cessation of the study. Determination of the proper place of aminothiol therapy in this disease will depend upon further clinical trial with patients whose kidney function has not deteriorated to the point of irreversible change, accompanied by careful monitoring of plasma aminothiol levels.

Comparisons of ecorational and chemical insecticides against crucifer flea beetle (Coleoptera: Chrysomelidae) on canola.

Studies were done comparing the insecticides SpinTor (spinosad), BotaniGard (Beauveria bassiana), Neemix (azadirachtin), and Surround (kaolin, a clay) with conventional chemical insecticides Capture (bifenthrin) and Helix XTra (thiamethoxam), all applied at seven rates in a 7-d assay to assess their impact on adult crucifer flea beetle, Phyllotreta cruciferae (Goeze) (Coleoptera: Chrysomelidae). Lethal time (LT) required for 25, 50, and 75% mortality (LT25, LT50, and LT75) and relative potencies for the insecticide concentration groupings (0, 1X-1.5X, and 2X- 4X) were estimated for each treatment by using survival functions. P. cruciferae mortality increased in response to increasing concentrations, especially for Helix XTra, Capture and SpinTor. After 2 d of exposure in 2002, mortality ranged from 54 to 78% for Helix XTra, from 60 to 94% for Capture, and from 66 to 92% for SpinTor across concentrations. In 2003, flea beetle mortality ranged from 37 to 60%, from 29 to 63%, and from 23 to 52% on exposure to Helix XTra, Capture, and SpinTor, respectively, for 2 d. The LT50 and relative potencies of the insecticides were in the order of Helix XTra, Capture, and SpinTor > BotaniGard, Neemix, and Surround. In 2002, LT50 values were 1 and 2 d for Capture and SpinTor, 2 d for BotaniGard, and 3 d for Neemix and Surround. In 2003, LT50 values occurred between 2 and 4 d after exposure to Helix XTra, Capture, and SpinTor, with LT50 values of 5-7 d on exposure to BotaniGard, Neemix, and Surround. SpinTor seems to be a suitable ecorational insecticide in canola, Brassica napus L., for P. cruciferae management.

Comparative evaluation and economic potential of ecorational versus chemical insecticides for crucifer flea beetle (Coleoptera: Chrysomelidae) management in Canola.

From 2001 to 2004, field studies were conducted to evaluate the effect of the ecorational insecticides SpinTor (spinosad), BotaniGard (Beauveria bassiana), Neemix (azadirachtin), and Surround (kaolin) against crucifer flea beetle on canola, Brassica napus L., at the cotyledon stage. The ecorational treatments were compared with a standard foliar chemical insecticide, Capture (bifenthrin), and the chemical seed treatment insecticide Helix XTra (thiamethoxam). This study indicated that flea beetle injury was lower for Helix XTra, Capture, and the ecorational insecticide SpinTor. SpinTor was less effective when flea beetle populations were relatively high (200-300 per trap-week). Yields for chemical insecticide treatments were always greater than SpinTor, with differences being the smallest (68-374 kg/ha) at low levels of flea beetle feeding injury. Differences were greatest when canola seedling injury was high (775-1,364 kg/ha). Yield differences between the conventional insecticides and BotaniGard, Neemix, and Surround were 119-439 and 61-2,248 kg/ha at low and high flea beetle feeding injury, respectively. Although yield differences between SpinTor and chemical insecticides were relatively small at lower levels of flea beetle injury, net losses ranged from $47 to $151/ha when SpinTor was used as an alternative to a standard chemical seed treatment, Helix XTra. This suggests that SpinTor would not be a viable alternative to the chemical insecticide. Net losses ranged from $30 to $266/ha when BotaniGard, Neemix, and Surround were used as alternatives to the seed treatment.

Metabolism of furan fatty acids in fish.

In vivo experiments on interconversions of furan fatty acids in fish are described. Administration of 2- or 3-14C-labelled furan fatty acids showed that the heterocycle does not interfere with conversions at the carboxyl group, such as shortening and elongating the chain, or its reduction to alcohol. There was no indication for desaturation of proximal chains, methylation or demethylation of the ring, or changes in the terminal chains. According to these restricted metabolic correlations, the furan fatty acids can be classified in specific structural families of bis-homologs. Distinct parent furan compounds are likely for each of these families. [1-14C]Acetate was incorporated by fish into furan fatty acids. Their chemical oxidation showed that only the resulting dicarboxylic fragments were labelled. They represent the proximal chain including alpha-C of the ring. Label was not found in the monocarboxylic acids which represent terminal chains with alpha'-C, and ring-methyl substituents with beta- and beta'-C. Accordingly, fish do not synthesize from acetate the terminal alkyl chain including the carbons in the cyclic portion of the furan fatty acids.

Calcium ion binding to human and bovine factor X.

Human and bovine factor X contain 11 and 12 glutamyl residues, respectively, within the first 40 amino terminal residues that are post-translationally modified to gamma-carboxyglutamyl (Gla) residues. We have measured calcium ion binding to human factor X by equilibrium dialysis. This is the first examination of calcium ion binding to human factor X. We have also re-examined the equilibrium dialysis binding of calcium ions to bovine facor X in order to compare the two species. The data was analysed using a variety of models that allow for more than one class of binding site and for co-operativity among binding sites. Calcium ion binding to human factor X fits a model that had two classes of sites: one class with a single site that had an affinity of 0.1 mM and a second class with 19 equivalent, non-interacting sites with an average affinity of 3.5 mM. There was no evidence for co-operativity in calcium ion binding. Calcium ion binding to bovine factor X was best stimulated by a model that assumed one tight site, four co-operative sites, and 18 equivalent, non-interacting sites. To examine the co-operativity seen in calcium ion binding to bovine factor X, calcium ion binding to isolated Gla region (residues 1-44) and Gla-domainless factor X was measured by equilibrium dialysis. Calcium ion binding to Gla-domainless factor X was simulated by a model that had two classes of sites: one class with a single site that had an affinity of 0.25 mM, and a second class that had 15 sites with very low affinity sites (greater than 15 mM).(ABSTRACT TRUNCATED AT 250 WORDS)

Renal hypertension in children.

Preliminary results of this retrospective-prospective analysis of renal hypertension in 110 children indicate that hypertension may be secondary to a wide variety of acute progresive, and chronic renal diseases which may be either congenital or acquired. Affected children may be detected at any time from infancy through adolescence. Symptoms usually associated with acute glomerulonephritis (i.e., headache, swelling, nausea, vomiting, anorexia, fatigue, dizziness, and fever) occur in both acute and chronic renal diseases associated with hypertension. Headache and swelling are the most common symptoms in this series. Peripheral edema, rales, and increased heart size were found in between 10 and 25% of these children. Differential diagnosis may be approached by a consideration of causes of acute and chronic hypertension. The child with chronic renal disease usually presents with a long history of fatigability, poor growth, and pallor, and laboratory tests reveal elevation of the creatinine and BUN along with anemia, hypocalcemia, and hyperphosphatemia. In contrast, the child with acute renal disease and hypertension presents with a history of prior good health followed by the abrupt onset of signs and symptoms of renal disease; laboratory tests usually reveal modest elevations of creatinine and BUN, anemia is unusual, an abnormal urinalysis is common, and serum calcium and phosphorous levels are usually normal. Renovascular and asymmetric renal parenchymal disease represent uncommon but important conditions because surgery may be curative. Treatment may be surgical, medical, or combined. Surgical conditions include renal trauma, hydronephrosis, asymmetric renal disease, and renal arterial disease. Adequate blood pressure control without medication can be expected following surgery in instances of unilateral involvement with a normal contralateral kidney. Meticulous assessment of the contralateral kidney is needed to determine that it is normal. If surgery is unsuccessful or is not indicated, pharmacologic therapy is initiated with a stepwise regimen starting with the mildest agent (e.g., thiazides) and then adding additional antihypertensive drugs when adequate blood pressure control has not yet been achieved. The goal of therapy is the lowest, safest, tolerated blood pressure levels. Long-term, carefully designed studies of antihypertensive agents for children with renal hypertension are not available. The need for collection and critical analysis of data concerning the clinical course of children with renal hypertension is evident from a review of the literature and from the preliminary data presented in this series. The presentation of such information and a critique of outcome variables will provide a basis for program planning for affected children and improvement in patient care where indicated.

The occurrence and distribution of furan fatty acids in spawning male freshwater fish.

Furan fatty acids (F acids) have been found in the livers and/or testes of 20 species, representing 9 families, of male freshwater fish. In 9 species they are major components of the lipids while in the remaining 11 species they occur to a much lesser extent. The F acids in some species reach a maximum concentation in the testes lipids, and minimum liver lipid concentration, at spawning. In all species in the testes, the F acids are confined almost exclusively to the triglyceride fraction while, in the liver lipids, they are found, in order of decreasing concentration, in the cholesteryl esters, the triglycerides, and the phospholipids. In the lipids of many individuals F6, 12,15-epoxy-13,14-dimethyleicosa-12,14-dienoic acid, is the major fatty acid present. It is presumed that these acids perform some as yet unidentified metabolic function. Isolation technology and identification of F acids by a specific thin layer chromatographic spray reagent are discussed.

Physical therapy and exercise-induced bronchospasm.

Most asthmatic children develop a significant degree of bronchospasm from exercise which restricts their active participation in outdoor play and sports and sometimes leads to many social and psychological problems. No specific physiological or immunological factors have yet been found to explain the basis of this exercise-induced bronchospasm (EIB). It is also unrelated to age, sex, or severity of asthma. Some investigators have hypothesized that EIB may be a conditioned response resulting from the association between the physical exertion and breathing difficulty which is frequently experienced by these children during their asthmatic attacks. Physical activity programs, organized around themes of progressive and interval training periods, may be quite helpful in reducing the intensity of EIB.

A management science approach to contingency models of organizational structure.

This study demonstrates the applicability of a quantitative modeling approach, specifically goal programming, in operationalizing the relationship between environmental variables and specific organizational structural variables for optimal goal attainment. A goal programming model is developed to analyze and determine the optimal relationships for goal attainment.

Deconditioning of exercise-induced asthma.

The majority of asthmatic children develop a significant degree of bronchospasm after a moderate amount of exercise. Etiology of this phenomenon has remained unknown. Pulmonary function tests, measurements of blood gases, and immunological assessments have been essentially normal. This study was designed to investigate the role of conditioning process in the development of exercise-induced bronchospasm (EIB). Fifty asthmatic children, between the ages of 8 and 15, were subjected to a standardized test of exercise. Thirty-six of the children who developed EIB were divided into an experimental and a control group. The experimental procedure was designed as a classical extinction procedure in which the conditioned stimulus (exercise) was presented without the occurrence of conditioned response of EIB. Only the experimental group received isoproterenol inhalation before the exercise to prevent the occurrence of EIB, while the control groups received plain air in a similar manner. The experimental group showed a significant improvement after the extinction procedure. A 6 month follow-up indicated that the majority of the children in the experimental group maintained the gains that were acquired during the experimental procedure.

Computed tomography characteristics of intermesenteric hematomas.

Abdominal bleeding may accumulate in the peritoneal cavity, retroperitoneal compartments, intraabdominal organs such as liver or bowel wall, or, rarely, in the intestinal mesentery. During the past 3 years we have encountered four cases of isolated mesenteric hematomas that were demonstrated on abdominal computed tomography examination. In this report, we present the clinical and computed tomography findings of intermesenteric hematomas with review of the pertinent mesenteric anatomy, and add four more cases to the two cases reported in two earlier reports.

The gastric bubble: roentgen observations.

The appearance of the stomach bubble provides many clues to underlying thoracoabdominal disorders. Illustrated in this article are (1) the major complications of large hiatal hernias: intrathoracic gastric volvulus and ulceration; (2) diaphragmatic abnormalities including inversion of the hemidiaphragm and intrathoracic displacement of abdominal contents because of diaphragmatic laceration or congenital herniation; (3) extrinsic displacement of the stomach bubble by splenomegaly (the occurrence of which in association with radiographic abnormalities in the chest--cardiomegaly, interstitial lung disease, mediastinal or hilar adenopathy--helps form a differential diagnosis); and (4) situs abnormalities for the analysis of which a simplified schema is presented.

Percutaneous enteral alimentation: gastrostomy versus gastrojejunostomy.

Scintigraphy was used to detect gastroesophageal reflux, determine whether percutaneous gastrostomy (PG) tubes cause reflux, and help in the choice between PG tubes versus percutaneous gastrojejunostomy (PGJ) tubes. During a 2-year period, 46 patients were evaluated with scintigraphy immediately before and 1 week after PG tube placement. Findings in the pre- and postplacement reflux studies were the same in 39 patients (85%). Proof of reflux on either study was considered an indication for conversion to the PGJ tube; at least one study was positive for reflux in 21 patients (46%). All patients were followed up for tube complications, pneumonia, and cause of death. During follow-up, six of 24 patients correctly maintained with PG tubes (25%) and 18 patients with PGJ tubes (39%) developed pneumonia, the cause of death in four of 24 patients with PG tubes (17%) and five of 18 patients with PGJ tubes (28%). The PG tube does not induce reflux, and scintigraphy is useful in selection of patients who can be safely maintained with the PG tube without an increase in the morbidity or mortality associated with reflux and aspiration.

High-resolution microcoil NMR for analysis of mass-limited, nanoliter samples.

An improved nanoliter-volume NMR probe design places the microcoil and capillary at the magic angle (57.7 degrees) with respect to the external magnetic field. Using an NMR probe which requires a total sample volume of just 200 nL, high-resolution 300-MHz 1H-NMR spectra (line width, 0.6 Hz) are presented of 10 mM alpha-bag cell peptide for an observe quantity of 45 ng (50 pmol in 5 nL). For the volume of sample inside the microcoil (the observe volume, Vobs), the 3 sigma limit of detection (LOD) is 9 ng (10 pmol, 2mM) for data obtained in 15 h. To reduce the data acquisition time, a probe with a greater Vobs is developed. As an example of a rapid, mass-limited analysis, a concentration corresponding to 400 ng of menthol dissolved in Vobs = 31 nL (82.6 mM) yields a spectrum in 9 min (LOD = 6.9 ng, 44 pmol, 1.4 mM). To illustrate improvements in concentration sensitivity, a spectrum is acquired in 45 min for 400 ng of menthol dissolved in a total sample volume of 200 nL (12.8 mM). Compared to a commercial nanoprobe for the same mass of menthol, these two examples reduce data acquisition time by at least 95%. Both model compounds demonstrate substantially improved concentration LODs compared to those obtained in previous high-resolution, microcoil NMR work. These advances illustrate the utility of enhanced sensitivity provided by NMR microcoils applied to nanoliter volumes of mass-limited samples.

Determination of magnesium binding to macromolecules.

An equilibrium dialysis technique for examining magnesium binding to macromolecules is described. The technique is used to determine the binding constants of magnesium to human prothrombin. This procedure should be of great utility for many biochemical systems which exhibit magnesium affinity.

Computed tomography of pulmonary thromboembolism and infarction.

Computed tomographic findings in 18 patients with pulmonary thromboembolism are retrospectively reviewed. In the majority of patients, thromboembolism was not suspected clinically. The CT findings can be divided into two groups: vascular and parenchymal changes. The most frequent vascular findings is an intraluminal filling defect or defects due to thrombus. The most frequent parenchymal finding is a triangular (wedge-shaped) pleural-based soft tissue attenuation lesion. Although CT is not a primary diagnostic tool in the evaluation of pulmonary thromboembolism, CT may be helpful in diagnosis of pulmonary embolism, when evaluating an undiagnosed parenchymal density.

Renovascular hypertension in children and adolescents.

Renovascular disease often leads to hypertension in children. The most frequent cause is fibromuscular dysplasia of focal type affecting main and peripheral arteries. Diastolic readings in excess of 110 mm Hg with normal serum creatinine and urinalysis are suggestive of renovascular disease. Excretory urography was positive in 65% of patients with unilateral disease. Radionuclide scans complement a positive excretory urogram but may be positive when the urogram is negative. Plasma renin activity was raised in the majority of patients; if the patient does not have peripheral branch stenosis, the renal vein renin ratio will lateralize in unilateral renal disease. The overall results of surgery are encouraging: 86% of surgical procedures alleviated hypertension in unilateral disease.

Nanoliter-volume 1H NMR detection using periodic stopped-flow capillary electrophoresis.

Recent advances in the analysis of nanoliter volumes using 1H NMR microcoils have led to the application of microcoils as detectors for capillary electrophoresis (CE). Custom NMR probes consisting of 1-mm-long solenoidal microcoils are fabricated from 50-micron diameter wire wrapped around capillaries to create nanoliter-volume detection cells. For geometries in which the capillary and static magnetic field are not parallel, the electrophoretic current induces a magnetic field gradient which degrades the spectroscopic information obtainable from CE/NMR. To reduce this effect and allow longer analyte observation times, the electrophoretic voltage is periodically interrupted so that 1-min high-resolution NMR spectra are obtained for every 15 s of applied voltage. The limits of detection (LODs; based on S/N = 3) for CE/NMR for arginine are 57 ng (330 pmol; 31 mM) and for triethylamine (TEA) are 9 ng (88 pmol; 11 mM). Field-amplified stacking is used for sample preconcentration. As one example, a 290-nL injection of a mixture of arginine and TEA both at 50 mM (15 nmol of each injected) is stacked severalfold for improved concentration LODs while achieving a separation efficiency greater than 50,000. Dissolving a sample in a mixture of 10% H2O/90% D2O allows H2O to serve as the nearly ideal neutral tracer and allows direct observation of the parabolic and flat flow profiles associated with gravimetric and electrokinetic injection, respectively. The unique capabilities of CE and the rich spectral information provided by NMR spectroscopy combine to yield a valuable analytical tool, especially in the study of mass-limited samples.

Relative affinity of Ca(II) and Mg(II) ions for human and bovine prothrombin and fragment 1.

Equilibrium dialysis results are presented for Ca(II) and Mg(II) ion binding to human and bovine prothrombin and fragment 1. Ca(II) ions bind cooperatively, Mg(II) does not.