Reverse enhancement of hemorrhagic brain lesions on postcontrast MR: detection with digital image subtraction.

PURPOSETo investigate the decrease in signal intensity on T1 - weighted MR images of some hemorrhagic intracranial lesions after administration of contrast material.METHODSPostprocessing digital image subtraction was performed in 16 MR studies (13 patients) of lesions that showed hyperintensity on noncontrast T1-weighted images. Repetition time and echo time were identical for all precontrast and postcontrast studies. Regions of interest were measured in each lesion, contralateral white matter, and background (before and after contrast enhancement).RESULTSIn six of 16 MR studies, a significant net decrease in signal intensity was seen within the hemorrhagic lesion after contrast enhancement (reverse enhancement). All the lesions were hematomas within residual or recurrent malignant tumors.CONCLUSIONSDigital image subtraction confirms the existence of reverse enhancement. This phenomenon is due to the combined T2-shortening effects of two paramagnetic substances, methemoglobin and gadolinium, which cause the signal reduction produced by the T2 effects to occur at lower concentrations of gadolinium.     

FM sonography in diffuse liver disease: prospective assessment and blinded analysis

FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.     

Repeated administration of desmethylimipramine blocks the reserpine-induced increase in tyrosine hydroxylase mRNA in locus coeruleus neurons of the rat.

The levels of tyrosine hydroxylase and galanin mRNA were measured by in situ hybridization histochemistry in the rat locus coeruleus after repeated (21 days) administration of desmethylimipramine (10 mg/kg/day), of reserpine (0.25 mg/kg/day), of coadministered desmethylimipramine and reserpine, or of vehicle. Reserpine administration resulted in increased levels of both tyrosine hydroxylase and galanin mRNAs in locus coeruleus neurons as compared to vehicle-treated controls. Administration of desmethylimipramine alone failed to alter either the tyrosine hydroxylase or galanin mRNA. However, coadministration of desmethylimipramine with reserpine blocked the elevation in tyrosine hydroxylase mRNA induced by reserpine alone.     

Pre-clinical pharmacology of ICI D2138, a potent orally-active non-redox inhibitor of 5-lipoxygenase.

1. This paper describes the pre-clinical pharmacology of ICI D2138, a potent orally-active non-redox inhibitor of 5-lipoxygenase which is undergoing clinical evaluation. 2. ICI D2138 potently inhibited leukotriene synthesis in murine peritoneal macrophages (IC50 = 3 nM) and human blood (IC50 = 20 nM). In human and dog blood, ICI D2138 did not inhibit thromboxane B2 synthesis at a concentration of 500 microM, thus the selectivity ratio (cyclo-oxygenase: 5-lipoxygenase) was greater than 20,000. In contrast, zileuton (a 5-lipoxygenase inhibitor also undergoing clinical evaluation) exhibited a selectivity ratio of 15-100. 3. ICI D2138 potently and dose-dependently inhibited ex vivo leukotriene B4 (LTB4) synthesis by rat blood with ED50 values of 0.9, 4.0 and 80.0 mg kg-1 p.o. at 3, 10 and 20 h respectively after dosing. Similar activity was observed for inhibition of LTB4 production in a zymosan-inflamed rat air pouch model. Zileuton produced ED50 values of 5 and 20 mg kg-1 at 3 and 10 h respectively. 4. Oral administration of 1, 3 or 10 mg kg-1 ICI D2138 to dogs produced maximal inhibition of ex vivo LTB4 synthesis by blood for 5, 9 and 31 h respectively. A dose of 5 mg kg-1 p.o. of zileuton caused maximal inhibition of LTB4 for 24 h. 5. Oral administration of 10 mg kg-1 ICI D2138 caused total inhibition of LTB4 production in zymosan-inflamed rabbit knee joint. 6. Topical administration of ICI D2138 to rabbit skin caused a dose-related inhibition of arachidonic acid-induced plasma extravasation with an ID30 of 1.08 nmol per site.(ABSTRACT TRUNCATED AT 250 WORDS)     

Case management: managing the nurse case manager

Nurse executives and nurse managers have become proactive in response to the health care crisis by creating and implementing innovative health care delivery models such as nursing case management. Nursing case management utilizes a nurse as case manager and the unit-based system of managed care to achieve financial and clinical outcomes for target patient groups. Nurse managers can support the nursing case management model best by practicing good managerial skills, developing a participative style of leadership, and empowering the nurse case manager.     

Clinical validation of a miniature nuclear probe system for continuous on-line monitoring of cardiac function and ST-segment

A new, miniature cesium iodide/photodiode nuclear probe (the "Cardioscint") has been developed for continuous on-line measurement of left ventricular function and the ST-segment. Ejection fraction (EF) measurements in 77 patients were compared with gated equilibrium radionuclide ventriculograms. The probe was positioned over the left ventricle by first using a blind positioning algorithm and then by using the gamma camera. Background was measured both manually and automatically. There was good correlation between probe (positioned blind) and gamma camera EF with both manual (r = 0.80, n = 65) and automatic (r = 0.78, n = 66) backgrounds. Use of the gamma camera did not significantly alter the results. Correlation between the probe stroke counts and thermodilution-derived stroke index during atrial pacing in six subjects was also satisfactory (r = 0.69, n = 102). Thus, the Cardioscint is able to provide a reliable estimate of EF and can track rapid changes in cardiac volumes.     

Prognostic factors for patients with chronic myeloid leukaemia in chronic phase treated with imatinib mesylate after failure of interferon alfa.

We assessed clinical results in 145 patients with chronic myeloid leukaemia in chronic phase who satisfied criteria for interferon-alpha failure and were thus eligible for treatment with imatinib at the Hammersmith Hospital. We used univariate and multivariate analyses to develop a risk score based on features defined after treatment for 3 months. We identified a low neutrophil count and poor cytogenetic response (<35% Ph-negative marrow metaphases) at 3 months as principal independent predictive factors and incorporated them into a three-tier prognostic scoring system for individual patients. For patients in the low-, intermediate- and high-risk groups, the probabilities of survival at 24 months were 100, 82 and 40% (P<0.0001) and progression-free survival 100, 66 and 15% (P<0.0001), respectively. This Hammersmith prognostic scoring system was validated with an independent cohort of patients treated at another UK centre.