Brain DSC MR Perfusion in Children: A Clinical Feasibility Study Using Different Technical Standards of Contrast Administration.

BACKGROUND AND PURPOSE: Dynamic susceptibility contrast MR perfusion imaging has limited results in children due to difficulties in reproducing technical standards derived from adults. This prospective, multicenter study aimed to determine DSC feasibility and quality in children using custom administration of a standard dose of gadolinium. MATERIALS AND METHODS: Eighty-three consecutive children with brain tumors underwent DSC perfusion with a standard dose of gadobutrol administered by an automated power injector. The location and size of intravenous catheters and gadobutrol volume and flow rates were reported, and local and/or systemic adverse effects were recorded. DSC was qualitatively evaluated by CBV maps and signal intensity-time curves and quantitatively by the percentage of signal drop and full width at half-maximum, and the data were compared with the standards reported for adults. Quantitative data were grouped by flow rate, and differences among groups were assessed by analysis of covariance and tested for statistical significance with a t test. RESULTS: No local or systemic adverse events were recorded independent of catheter location (63 arm, 14 hand, 6 foot), size (24-18 ga), and flow rates (1-5 mL/s). High-quality CBV maps and signal intensity-time curves were achieved in all patients, and quantitative evaluations were equal or superior to those reported for adults. No significant differences (P ≥ .05) were identified among the higher-flow-rate groups in the quantitative data. CONCLUSIONS: A custom administration of a standard dose of gadobutrol allows safe and high-quality DSC MR perfusion imaging in children.

Postoperative MR Imaging of Spontaneous Transdural Spinal Cord Herniation: Expected Findings and Complications.

BACKGROUND AND PURPOSE: Spontaneous transdural spinal cord herniation is no longer a rare cause of myelopathy. The high frequency of diagnoses has led to an increase in the number of surgical procedures. The purpose of this study was to describe the spectrum of postoperative MR imaging findings concerning spontaneous transdural spinal cord herniation and to provide a practical imaging approach for differentiating expected changes and complications after an operation. MATERIALS AND METHODS: We retrospectively reviewed MR images from 12 patients surgically treated for spontaneous transdural spinal cord herniation. Surgery comprised either dural defect enlargement or duraplasty procedures. Postoperative follow-ups included at least 3 (early, intermediate, late) MR imaging studies. MR images were analyzed with respect to 3 spinal compartments: intradural intramedullary, intradural extramedullary, and extradural. The meaning and reliability of changes detected on MR images were related to their radiologic and clinical evolution with time. RESULTS: Spinal cord realignment has been stable since the early study, whereas spinal cord signal and thickness evolved during the following scans. Most extramedullary and extradural changes gradually reduced in later MR images. Three patients treated with dural defect enlargements experienced the onset of new neurologic symptoms. In those patients, late MR images showed extradural fluid collection and the development of pial siderosis. CONCLUSIONS: Our findings demonstrate the spectrum of postoperative imaging findings in spontaneous transdural spinal cord herniation. Spinal cord thickness and signal intensity continued to evolve with time; most extramedullary postsurgical changes became stable. Changes observed in later images may be suggestive of complications.

Differential diagnosis of parotid gland tumours: which magnetic resonance findings should be taken in account?

Our aim was to define typical magnetic resonance (MRI) findings in malignant and benign parotid tumours. This study is based on retrospective evaluation of pre-surgical MRI of 94 patients with parotid gland tumours. Histology results were available for all tumours. There were 69 cases of benign (73%) and 25 cases of malignant (27%) tumours, including 44 pleomorphic adenomas, 18 Warthin's tumours, 7 various benign tumours, 6 squamous cell carcinomas, 3 carcinoma ex pleomorphic adenomas, 2 mucoepidermoid carcinomas, 1 adenoid cystic carcinoma and 13 various malignant tumours. The following MRI parameters were evaluated: shape, site, size, margins, signal intensity (SI) on T1w and T2w images, contrast enhancement, signal of cystic content, presence or absence of a capsule, perineural spread, extraglandular growth pattern and cervical adenopathy. Statistical analysis was performed to identify the MRI findings most suggestive of malignancy, and to define the most typical MRI pattern of the most common histologies. Ill-defined margins (p < 0.001), adenopathies (p < 0.001) and infiltrative grown pattern (p < 0.001) were significantly predictive of malignancy. Typical findings of pleomorphic adenoma included hyperintensity on T2w images (p = 0.02), strong contrast enhancement (p < 0.001) and lobulated shape (p = 0.04). Typical findings of Warthin's tumour included hyperintense components on T1w images (p < 0.001), location in the parotid inferior process (p < 0.001) and mild or incomplete contrast enhancement (p = 0.01). SI on T1w and T2w images and contrast enhancement enables differential diagnosis between pleomorphic adenoma and Warthin's tumour.

Montelukast causes prolonged, potent leukotriene D4-receptor antagonism in the airways of patients with asthma.

Montelukast, a new specific oral cysteinyl LT3-receptor antagonist was evaluated for its activity in attenuating inhaled leukotriene D4 (LTD4) bronchoconstriction in patients with asthma. In two double-blind, placebo-controlled, randomized crossover studies, patients with mild asthma (forced expiratory volume in 1 second [FEV1] > or = 70%) were studied. In trial A, LTD4 challenge began 4 hours (peak plasma concentration) after a single dose of placebo or 5, 20, 100, and 250 mg montelukast. In trial B, and LTD4 challenge was started 20 hours after administration of placebo, 40 mg montelukast, or 200 mg montelukast. During each challenge, twofold increasing concentrations of LTD4 were inhaled until specific airways conductance (sGaw) decreased by at least 50% (PC50) or the highest concentration of LTD4 was inhaled. In trial A with all doses and in trial B with the 200 mg dose, bronchoconstriction was attenuated (50% fall in sGaw was not observed) up to the highest dose of LTD4 administered. In trial B, during the 40 mg period, only two of six patients exhibited a 50% fall in sGaw; PC50 ratios (montelukast 40 mg/placebo) were 18 and 45 in these two patients. These results indicate that montelukast is a highly potent and long-lasting antagonist of LTD4-induced bronchoconstriction in patients with asthma.

[Flow cytometry in micturitional urine: its clinical application in cases of bladder cancer]. / La citometria di flusso sulle urine minzionali: sua applicazione clinica in casi di neoplasia vescicale.

The paper discusses a particular use of flow cytometric analysis, namely the quantitative study of DNA in the cellular sediment obtained from micturitional urine in patients with vesical tumours. Forty cases of carcinoma of varying degrees and stages were studied and, despite the small number of cases, interesting results have emerged regarding the close correlation between the test and the different clinical, cytological and histopathological aspects of the disease, and relating to the relative simplicity of the method used.

[Our experience with the surgical treatment of the solitary ulcer syndrome of the rectum]. / La nostra esperienza nel trattamento chirurgico della sindrome dell'ulcera solitaria del retto.

The authors examine the question of the pathogenesis of solitary rectal ulcer syndrome (S.R.U.S), illustrating the importance of a correct differential diagnosis versus other relevant forms of disease affecting this region, particularly rectal cancer. They describe their experience with both the medical and surgical treatment of the syndrome.

Estratificación del riesgo de dengue en la ciudad de Puerto Ayacucho, estado Amazonas, Venezuela: Período 1995-2010 / Dengue fever risk stratification in Puerto Ayacucho city, Amazonas State, Venezuela: 1995-2010 period

El control del Aedes aegypti (vector principal del Dengue), se dificulta por la extensión y heterogeneidad de los barrios donde se encuentran los criaderos, la carencia de acceso permanente a servicios públicos y por la ausencia de vigilancia epidemiológica estricta y constante. Se registraron 2.603 casos de dengue confirmados por IgM-dengue, durante el período 1995-2010. El estudio se realizó en Puerto Ayacucho, capital del estado Amazonas con 98.824 habitantes. Los casos confirmados se agruparon de acuerdo con la localización de su residencia. La información se representó espacialmente para analizar los patrones espacio-temporales del dengue, estableciéndose una estratificación de la ciudad. La prevalencia de dengue mostró una correlación positiva con la persistencia por barrio, lo que permitió agruparlos en dos clases: (1) alta prevalencia y persistencia, con 66% de los casos confirmados, y (2) baja prevalencia y persistencia, con 34% de los casos. Se demuestra que en Puerto Ayacucho existen “focos calientes” o de mayor transmisión y “focos fríos” o de transmisión transitoria. En conjunto, los barrios incluidos en la categoría de alta prevalencia y persistencia representan 65,1% del área urbana. Este es el espacio geográfico en el cual recomendamos concentrar los esfuerzos de control. La estratificación de la ciudad e identificación de los barrios productores de casos, mostrando las áreas donde es más probable la transmisión del virus, permitirá concentrar los esfuerzos para mitigarla. El enfoque de las actividades de control basado en una estratificación, permite dirigir los programas hacia áreas más problemáticas.

Control of Aedes aegypti is difficult to perform due to the extent and variety of neighborhoods where the breeding grounds are found, the lack of permanent access to public services, and to the absence of a strict and constant epidemiological surveillance. 2,603 confirmed dengue cases (IgM-dengue) were recorded during the 1995-2010 period. This study was carried out in Puerto Ayacucho, main city of Amazonas State, Venezuela, with 98,824 inhabitants. Confirmed cases of individuals affected were grouped according to the location of their residence. Information is spatially represented to analyze space-time patterns of dengue, establishing a stratification of the city. The prevalence of dengue showed a positive correlation with the persistence per neighborhood, allowing to group the neighborhoods into two classes: (1) High prevalence and persistence, with 66% of the confirmed cases, and (2) low prevalence and persistence, with 34% cases. The study shows there are "hot spots" or higher transmission areas, and "cold spots" or transient transmission areas in Puerto Ayacucho. All the neighborhoods included in the category of high prevalence and persistence represent 65.1% of the urban area. This is the geographical area in which we recommend to concentrate control efforts. The stratification of the city and the identification of case-producing neighborhoods, showing the areas where virus transmission is most likely, will permit concentrating efforts to mitigate it. Focus of control activities based on a stratification study allows directing programs to most problematic areas.

Effects of montelukast (MK-0476); a potent cysteinyl leukotriene receptor antagonist, on bronchodilation in asthmatic subjects treated with and without inhaled corticosteroids.

BACKGROUND: Cysteinyl leukotriene release in association with airway inflammation is a feature of clinical asthma. The acute effects of montelukast (MK-0476), a potent, orally administered, specific cysteinyl leukotriene receptor antagonist, on airways obstruction was assessed in patients with mild to moderately severe asthma. METHODS: Twenty two asthmatic subjects were randomised to receive montelukast, 100 mg or 250 mg, or placebo in a double blind, three period, crossover trial. Ten of the patients were using concomitant inhaled corticosteroids. RESULTS: Montelukast increased the forced expiratory volume in one second (FEV1) from predose baseline values compared with placebo, the percentage point differences between montelukast and placebo being 8.6% (95% CI 3.6 to 13.6) and 8.5% (95% CI 3.5 to 13.5) for the 100 mg and 250 mg doses, respectively. CONCLUSION: Single oral doses of montelukast 100 mg and 250 mg produced significant increases in FEV1 irrespective of the concurrent use of inhaled corticosteroids in asthmatic subjects with airflow limitation.