Significance of acute multiple infarcts in multiple cerebral circulations on initial diffusion weighted imaging in stroke patients.

OBJECTIVES: We attempted to assess the frequency, clinical and neuroradiological features of concomitant Acute Multiple Infarcts in Multiple Cerebral Circulations (AMIMCC) and to classify their causes. SUBJECTS AND METHODS: Consecutive patients treated for MR DWI-confirmed infarcts were included in this cohort. We retrospectively analyzed all patients with AMIMCC of our prospective database, studying clinical and radiological features. Causes of stroke were classified using TOAST and ASCO system (atherosclerosis, small vessel disease, cardiac source, other causes). RESULTS: Eighty AMIMCC were identified out of 824 consecutive patients with MR DWI-confirmed infarcts (9.7%). Compared with single infarct patients, AMIMCC patients presented similar age and risk factors. Only 24 AMIMCC patients (30%) presented symptoms suggesting multiple lesions before MRI. Cardiac origin existed in 39 of 80 patients (49%) including atrial fibrillation in 25 patients. Other sources of AMIMCC were hematologic diseases or coagulopathies such as intravascular coagulation in relation with cancer (n = 6; 7,5%) and vasculitis or systemic disorders (n = 5;6,5%). AMIMCC also appeared to originate from unilateral carotid diseases or intracranial stenosis, mostly atheromatous, in association with anatomic variations(n = 9;11%). In 21 patients, no cause was identified despite extensive investigations (26%). According to TOAST classification, 62% had a definite source for infarcts, 67% according to ASCO grade 1 classification. MRI data did not permit to orientate etiological explorations according to DWI appearance, associated leucoaraiosis or previous infarcts on FLAIR or microbleeding on gradient-echo sequences. CONCLUSIONS: AMIMCC are not rare and mostly need MRI to be detected. Multiple and various etiologies are implicated, including cardioembolic diseases in half of them, but also hematologic disorders and angeitis.

Liquid chromatography method for separation of clindamycin from related substances.

A reversed-phase liquid chromatography method has been developed for the separation of clindamycin from 7-epiclindamycin, clindamycin B, lincomycin, lincomycin B, 7-epilincomycin and other impurities of unknown identity. The method uses a Hypersil ODS, 5 microm, 250 x 4.6 mm i.d. column maintained at 45 degrees C. The mobile phase comprises acetonitrile phosphate buffer (1.35% v/v phosphoric acid, adjusted to pH 6.0 with ammonium hydroxide)-water (35:40:25, v/v) at a flow rate of 1.0 ml/min. UV detection is performed at 210 nm. The method was tested on several C-18 columns and showed good robustness. Robustness was further evaluated by performing a full-fraction factorial design experiment. The method showed good selectivity, linearity, and repeatability. It is also suitable for analysis of clindamycin formulations.