Effect of radiographic positioning on interpretation of cubital joint congruity in dogs

OBJECTIVE: To ascertain effects of x-ray beam centering and limb position on apparent congruity of a normal cubital joint (elbow). ANIMALS: 6 skeletally mature male Treeing Walker Coonhounds without physical, radiographic, or gross evidence of elbow abnormalities. PROCEDURE: Relative movement among humerus, radius, and ulna and measured joint space width on mediolateral and craniocaudal radiographic views was compared, using various x-ray beam centering and limb positions. RESULTS: Highest agreement and greatest certainty on subjective determination of congruity was for the flexed 90 degrees mediolateral radiographic view with the x-ray beam centered on the elbow. Distortion artifact of the proximal ulnar measurements was significant when the x-ray beam was centered on the midpoint of the radius. On the mediolateral view, the humeroradial joint space became significantly wide when the elbow was flexed. On the craniocaudal view, maximal humeroradial joint space width was obtained when the x-ray beam bisected the angle of the joint or was angled +30 degrees toward the humerus. CONCLUSIONS: Artifact distortion of joint width affected objective and subjective assessment of elbow congruity when the limb was placed in extreme flexion or extension or when the x-ray beam was not centered over the area of interest. Optimal visualization of the humeroradial joint space on the craniocaudal view was achieved when the x-ray beam bisected the angle of the elbow or was slightly angled toward the humerus. CLINICAL RELEVANCE: Elbow congruity was best assessed on the flexed 90 degrees lateral radiographic view with the x-ray beam centered on the joint.     

Effect of local standards on the implementation of national guidelines for asthma: primary care agreement with national asthma guidelines

In vivo electrophysiological assays in anesthetized rats have been used to compare the effects of the 5HT1B/1D receptor agonist, naratriptan, on central trigeminal nociceptive processing from dural and cutaneous inputs with its effects on nociceptive processing in the spinal cord. Naratriptan inhibited responses of single trigeminal neurons, to noxious electrical and mechanical stimulation of the dura and face, dose dependently by a maximum of 67+/-3% and 70+/-18%, respectively, at 3 mg kg(-1) i.v. In contrast, naratriptan did not affect spinal dorsal horn neuronal responses to noxious mechanical stimulation of the hind-paw. These findings suggest that 5HT1B/1D receptors have differential effects on nociceptive processing in the trigeminal versus spinal dorsal horns and provide a potential explanation for the lack of general analgesic effects of brain penetrant 5HT(1B/1D) agonist antimigraine drugs.     

The complex pathology of trinucleotide repeats

The expansion of trinucleotide repeat sequences has now been shown to be the underlying cause of at least ten human disorders. Unifying features among these diseases include the unstable behavior of the triplet repeat during germline transmission when the length of the repeat exceeds a critical value. However, the trinucleotide repeat disorders can be divided into two distinct groups. Type I disorders involve the expansion of CAG repeats, which encode an expanded polyglutamine, inserted into the open-reading frame of a gene that is usually quite broadly expressed. Recently, mouse models for type I disorders have been developed and the basis of pathology is under study, both in these models and through biochemical and cell biological approaches. The type II disorders involve repeat expansions in noncoding regions of genes. The mechanisms by which these repeat expansions lead to pathology may be quite diverse.     

The analysis of phospholipids in soy lecithin by HPLC

A high performance liquid chromatography (HPLC) method is described for the HPLC analysis of major phospholipids in soy lecithin. The method entails dissolving soy lecithin in chloroform prior to analysis. The HPLC determination uses a normal phase column and a mobile phase of acetonitrilemethanol-H₃PO₄ with detection at 205 nm. The data presented illustrates that the method is rapid, accurate and precise for the determination of phospholipid in soy lecithin.     

Quantitative Analysis of Phytosterols in Edible Oils Using APCI Liquid Chromatography–Tandem Mass Spectrometry

Previous methods for the quantitative analysis of phytosterols have usually used GC–MS and require elaborate sample preparation including chemical derivatization. Other common methods such as HPLC with absorbance detection do not provide information regarding the identity of the analytes. To address the need for an assay that utilizes mass selectivity while avoiding derivatization, a quantitative method based on LC–tandem mass spectrometry (LC–MS–MS) was developed and validated for the measurement of six abundant dietary phytosterols and structurally related triterpene alcohols including brassicasterol, campesterol, cycloartenol, β-sitosterol, stigmasterol, and lupeol in edible oils. Samples were saponified, extracted with hexane and then analyzed using reversed phase HPLC with positive ion atmospheric pressure chemical ionization tandem mass spectrometry and selected reaction monitoring. The utility of the LC–MS–MS method was demonstrated by analyzing 14 edible oils. All six compounds were present in at least some of the edible oils. The most abundant phytosterol in all samples was β-sitosterol, which was highest in corn oil at 4.35 ± 0.03 mg/g, followed by campesterol in canola oil at 1.84 ± 0.01 mg/g. The new LC–MS–MS method for the quantitative analysis of phytosterols provides a combination of speed, selectivity and sensitivity that exceed those of previous assays.     

Solid‐phase extraction of phenolic compounds with poly[metalloprotoporphyrin IX]

A highly insoluble metalloporphyrin polymeric material was used as sorbent for the solid‐phase extraction of phenolic compounds. Substantial quantities of phenols (40 to 60 mg/g polymer) were absorbed from aqueous solution comparing satisfactorily with other extraction methods. The polymeric phase presented similar K_SPE values for the hydrophobic compounds tested such as p‐chlorophenol, BPA, p‐nitrophenol, and a significant lower value for the more hydrophilic p‐aminophenol and cresol. Several metallic complexes of protoporphyrin IX (Co²⁺, Cu²⁺, Ni²⁺, Zn²⁺, and Fe³⁺) have been tested. The analytes were extracted with high recoveries at acid and neutral pH values, whereas at pH 10 low recoveries were obtained. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3038–3043, 2001     

Highly thermally conductive hexagonal boron nitride/alumina composite made from commercial hexagonal boron nitride

Hexagonal BN is an unusual material in that it is both highly thermally conductive as well as an electrical insulator. Additionally, hBN is also thermally stable in air. This unusual combination of properties makes hBN of significant interest for thermal management. Unfortunately, hBN is not easily consolidated into substrates without the addition of second phases which generally result in poorer thermal performance. This research investigates the potential to utilize this material to dissipate heat from high‐voltage, high‐power electrical devices. Specifically, a process to coat individual platelets of commercial hexagonal BN powder with a layer of amorphous aluminum oxide was developed. The coated hexagonal BN was then hot‐pressed to form a highly thermally conductive substrate. The process to coat hexagonal BN platelets with aluminum oxide was accomplished by mixing hexagonal BN with AlCl₃ containing some water, then evaporation of excess AlCl₃ to form a Al, Cl, and O layer on hexagonal BN. This product was then heated in air to convert the surface layer into aluminum oxide. Following hot pressing to 1950°C and 10 ksi, the consolidated composite has through‐plane and in‐plane thermal conductivity of 14 and 157 W·(m·K)^?1, respectively, at room temperature.