Technical factors of CT angiography studied with a carotid artery phantom.

PURPOSETo evaluate scanning parameters (conventional versus spiral CT, section thickness, and pitch) and vessel orientation in the performance of CT angiography.METHODSConventional CT and 1.0-, 1.5-, and 2.0-pitch spiral CT acquisitions of a carotid phantom designed with vessels oriented parallel to the z-axis, 45 degrees oblique, and perpendicular to the z-axis were obtained with section thicknesses of 2, 4, and 8 mm. The phantom contained 32 vessels with 0% to 100% stenoses. Normal and stenotic luminal diameters were measured and the number of artifacts was assessed.RESULTSNo overall difference was observed among conventional and spiral CT acquisitions obtained with pitches of 1.0, 1.5, and 2.0. With thicker sections, CT angiographic accuracy decreased and artifacts increased. The three-vessel orientations were relatively comparable in accuracy in terms of the percentage of stenosis measured. Vessels parallel to the z-axis suffered less artifactual degradation. Unique artifacts, such as luminal distortion and beam hardening, were observed in vessels oriented at 45 degrees and perpendicular to the z-axis.CONCLUSIONUse of thinner sections with vessels oriented parallel to the z-axis optimizes CT angiographic quality. There is no apparent degradation with the use of spiral CT, and a pitch of 1.5 or 2.0 provides results equivalent to 1.0-pitch spiral studies.     

Pneumocandins from Zalerion arboricola. III. Structure elucidation.

Pneumocandin B0 (6) and six related lipopeptides are antifungal and anti-Pneumocystis carinii agents from mutants of Zalerion arboricola, whose structures were determined mainly on the basis of spectroscopic analysis. They belong, along with pneumocandin A0 (L-671,329) previously isolated from these laboratories, to the echinocandin class of antifungal agents. The product from base-catalyzed ring opening involving the hemiaminal position of the dihydroxyornithine residue of B0, has been clearly defined as 6b. Modifications were limited to the 3-hydroxy-4-methylproline, 3,4-dihydroxyhomotyrosine and 4,5-dihydroxyornithine residues of pneumocandin A0.     

Executive function impairments in children with attention-deficit hyperactivity disorder: do they differ between school and home environments?

OBJECTIVE: The primary purpose of this study was to compare parent and teacher reports of executive function (EF), as measured by the Behavior Rating Inventory of Executive Function (BRIEF), on a sample of children who had been diagnosed with attention-deficit hyperactivity disorder (ADHD). If differences were found, the secondary purpose was to explore these differences by determining which of the 8 BRIEF scales, each representing a different EF, would best predict symptoms of ADHD by the 2 proxy reporters. METHOD: We performed a secondary data analysis on the assessment information pertaining to 240 children, aged 5 to 15 years, accessing services at an urban Toronto psychiatric program specializing in ADHD. We compared parent and teacher ratings and applied logistical binary regressions to predict the probability of a child's meeting the criteria for clinically significant inattention and hyperactivity-impulsivity on the ADHD Rating Scale-IV. RESULTS: As expected, teachers reported more variety and severity of EF impairments than did parents. In addition, teachers used inhibition, organization of materials, and planning and organizing as predictors of ADHD symptoms, whereas parents relied predominantly on inhibition, working memory, and planning and organizing as the risk factors. CONCLUSION: Consistent with the current theory, EF impairments, particularly in inhibition, appear to underlie the behavioural manifestation of ADHD. However, parents and teachers do not always agree when reporting EF impairments at home and in school. Thus information from both types of informants is essential for understanding and treating children with this disorder.     

Neurofibromatosis, factor IX deficiency, and rhabdomyosarcoma

A paratesticular rhabdomyosarcoma occurred in a child with factor IX deficiency and neurofibromatosis, illustrating the need to consider carefully the various etiologic possibilities of a soft-tissue mass in a child with neurofibromatosis and/or a bleeding disorder.     

Local cerebral glucose metabolic rates in obsessive-compulsive disorder. A comparison with rates in unipolar depression and in normal controls

We studied 14 patients with obsessive-compulsive disorder (OCD) by positron emission tomography and the fluorodeoxyglucose method, looking for abnormalities in local cerebral metabolic rates for glucose in brain structures that have been hypothesized to function abnormally in OCD. These patients were compared with 14 normal controls and 14 patients with unipolar depression. The patients with unipolar depression and OCD did not differ in levels of anxiety, tension, or depression. In OCD, metabolic rates were significantly increased in the left orbital gyrus and bilaterally in the caudate nuclei. This was apparent on all statistical comparisons with both controls and unipolar depression. The right orbital gyrus showed at least a trend to an increased metabolic rate in all comparisons. The metabolic rate in the left orbital gyrus, relative to that in the ipsilateral hemisphere (orbital gyrus/hemisphere ratio), was significantly elevated compared to controls and subjects with unipolar depression, and stayed high even with successful drug treatment. Though it was in the normal range in the morbid state, with improvement in OCD symptoms after drug treatment, the caudate/hemisphere metabolic ratio increased uniformly and significantly bilaterally. This ratio did not increase in patients who did not respond to treatment. Thus, OCD showed cerebral glucose metabolic patterns that differed from controls in both the symptomatic and recovered states.     

Allergen-Specific IgE Antibodies against Antigenic Components in Cow Milk and Milk Substitutes

Crossed radioimmunoelectrophoresis (CRIE) was used to study the presence of serum IgE against antigenic components of cow milk in 21 selected milk-allergic patients. The amount of each IgE specificity was estimated by a scoring system. The milk-allergic children had mainly IgE against alpha-lactalbumin, beta-lactoglobulin, albumin and immunoglobulin, the four major proteins of bovine whey, as well as IgE against three casein components. A serum pool from 1000 normal adults had IgE against the same whey protein, but in smaller amounts, and no IgE against the casein components. Eight cow milk-based formulae, commonly used for infant feeding, and goat milk were studied by the same method. It was found that six of the milk substitutes did not differ significantly from cow milk in antibody binding, but the two hydrolysed casein products, Nutramigen and Pregestimil, consisted of such small molecules that the rabbit antisera could not precipitate the hydrolysed proteins in the gels on the CRIE plates. It was therefore not possible to study their IgE binding, if any, by this method.     

Investigation of an outbreak of Moraxella conjunctivitis at a Navajo boarding school

In 1986, an outbreak of Moraxella follicular conjunctivitis occurred in girls attending a Navajo boarding school in New Mexico. We diagnosed 19 cases of culture-proven, and 21 of clinical conjunctivitis based on isolation of Moraxella from conjunctival cultures and the occurrence of symptoms significantly associated with positive culture. Sharing eye makeup was significantly associated with Moraxella-positive conjunctivitis (odds ratio [OR] = 7.2, P = .004) and showed a trend toward significance in those with clinical conjunctivitis (OR = 2.9, P = .09). Eyeliner and eye shadow were implicated (OR = 4.1, P less than .05). We cultured samples of 13 students' makeup; one third of the eyeliners were positive for Moraxella. Nasal carriage of Moraxella was found in 35 (44%) of the 79 female boarders and in 20 (21%) of 97 Navajo patients at two nearby clinics. In a prospective evaluation of the effect of patient education and rifampin therapy on the occurrence of conjunctivitis during an 11-month follow-up period, both types of intervention were successful in significantly reducing the rate of conjunctivitis when compared with that in a control group.