Background and Purpose-There is scant population-based information on functional outcome, survival, and recurrence for ischemic stroke subtypes. Methods-We identified all residents of Rochester, Minnesota, with a first ischemic stroke from 1985 through 1989 using the resources of the Rochester Epidemiology Project medical records linkage system. After reviewing medical records and imaging studies, we assigned patients to 4 major ischemic stroke categories based on National Institute of Neurological Diseases and Stroke Data Bank criteria: large-vessel cervical or intracranial atherosclerosis with stenosis (ATH, nϭ74), cardioembolic (CE, nϭ132), lacunar (LAC, nϭ72), and infarct of uncertain cause (IUC, nϭ164). We used the Rankin disability score to assess functional outcome and the Kaplan-Meier product-limit method and Cox proportional hazards regression analysis with bootstrap validation to estimate rates and identify predictors of survival and recurrent stroke among these patients. Results-Rankin disabilities were different across stroke subtypes at the time of stroke and 3 months and 1 year later (Pϭ0.001). LAC was associated with milder deficits compared with other subtypes. Mean follow-up among the 442 patients in the cohort was 3.2 years. Estimated rates of recurrent stroke at 30 days were significantly different (PϽ0.001): ATH, 18.5% (95% CI 9.4% to 27.5%); CE, 5.3% (95% CI 1.2% to 9.6%); LAC, 1.4% (95% CI 0.0% to 4.1%); and IUC, 3.3% (95% CI 0.4% to 6.2%). After adjusting for age, sex, and stroke severity, infarct subtype was an independent determinant of recurrent stroke within 30 days (Pϭ0.0006; eg, risk ratio for ATH compared with CEϭ3.3, 95% CI 1.2 to 9.3) but not long term (Pϭ0.07). Four of 25 recurrent strokes within 30 days were procedure-related, each in patients with ATH. Five-year death rates were significantly different (PϽ0.001): ATH, 32.2% (95% CI 21.1% to 43.2%); CE, 80.4% (95% CI 73.1% to 87.6%); LAC, 35.1% (95% CI 23.6% to 46.0%); and IUC, 48.6% (95% CI 40.5% to 56.7%). With adjustment for age, sex, cardiac comorbidity, and stroke severity, the subtype of ischemic stroke was an independent determinant of long-term (Pϭ0.018; eg, risk ratio for ATH compared with cardioembolicϭ0.47, 95% CI 0.29 to 0.77) but not 30-day survival (Pϭ0.2). Conclusions-Early recurrence rates for ischemic stroke caused by ATH are higher than those for other subtypes and higher than previous non-population-based studies have reported. Some of the increased risk of early recurrence among patients with ATH may be iatrogenic. Patients with LAC have better poststroke functional status than those with other subtypes. Survival is poorest among those with ischemic stroke with a cardiac source of embolism. (Stroke.

The existence of two conformational states of concanavalin A (Con A) with different metal ion binding properties has been recently demonstrated (Brown, R. D., Brewer, C. F., & Koenig, S. H. (1977) Biochemistry 16, 3883). Introduction of Mn2+ to the S1 site and Ca2+ to the S2 site of apo-Con A was shown to induce a conformational change in the protein, ascribed to a cis-trans isomerization of a peptide bond in the secondary structure, which results in extremely tight binding of the metal ions. This induced conformation is referred to as "locked" and the initial conformation as "unlocked". The locked ternary complex is identical with the native protein. In the present paper, we report evidence for the formation of a relatively stable, locked, ternary Ca2+-Con A complex that possesses properties similar to those of native Ca2+-Mn2+Con A. The experimental technique involves measurement of the magnetic field and time dependence of the nuclear magnetic relaxation rate (1/T1) of solvent water protons in solutions of Ca2+-Con A, after the addition of Mn2+ ion which slowly bind to the protein. The kinetic data can be fit by a model for Ca2+ interactions with Con A which indicates that Ca2+, in the absence of Mn2+, can bind at both the S1 and S2 sites of the protein and, furthermore, can induce the protein to undergo the unlocked to locked conformational transition. In terms of this model, the time-dependent binding of the Mn2+ ions is due to replacement of Ca2+ ions at the S1 sites in the locked protein. The off-rate of Ca2+ from the S2 site of the locked ternary Ca2+-Con A complex is much greater than that from the locked Ca2+-Mn2+-Con A complex. From the effects of added alpha-methyl D-mannopyranoside on the rate of replacement of Ca2+ by Mn2+ at the S1 site of the locked ternary Ca2+-Con A complex, it is concluded that the latter complex binds saccharides as strongly as the locked Ca2+-Mn2+-Con A complex. In addition, analysis of the data indicates that apo-Con A in the locked conformation binds alpha -methyl D-mannopyranoside with approximately 7% of the affinity of the fully metallized locked form of the protein. This strong saccharide-binding activity of locked apo-Con A, compared with that of the unlocked apo-Con A, was further demonstrated by equilibration of unlocked apo-Con A with alpha-methyl D-mannopyranoside, which resulted in the formation of the locked apo-Con A-saccharide complex. These results demonstrate that it is the locked conformation of Con A that is primarily responsible for saccharide-binding activity, and that the function of the bound metals is primarily to maintain the protein in the locked conformation.

The enzyme-linked colloidal gold affinity labelling technique was tested as a method to localize cellulose on thin sections of plant cell walls and slime mold spores. Commercially available cellulase from cultures of Trichoderma reesei, the main components being cellobiohydrolase I and II (CBH I, CBH II) and endoglucanase (EG), was linked to colloidal gold by using standard techniques and applied as a dilute, buffered suspension to thin sections. After brief exposure, e.g., 15-30 minutes, cellulose exposed on the surface of sections was labelled with the enzyme-gold complex. Poststaining did not appear to have a deleterious effect on the labelled sections. The specificity of labelling was demonstrated by its complete inhibition when carboxymethylcellulose was incorporated in the labelling mixture, by lack of labelling of 1,4-beta-mannans or 1,3-beta-xylans in noncellulosic walls of marine algae, by lack of labelling of 1,4-beta-glucans in chitin, by much lower labelling density when done at 4 degrees C, and by lack of labelling when sections were predigested with cellulase. Labelling with the crude commercial cellulase was compared to labelling with purified CBH I-, CBH II-, and EG-linked colloidal gold, and the labelling pattern was similar. This method was found useful on conventionally fixed material and required no special preparation other than the use of inert (Ni or Au) grids and 0.5% gelatin to reduce nonspecific binding of the gold complex. Labelling was similar in the several embedding resins tested: LR White, Lowicryl K4M, Epon 812, and Spurr's.(ABSTRACT TRUNCATED AT 250 WORDS)

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