Carotid Bulb Webs as a Cause of "Cryptogenic" Ischemic Stroke.

BACKGROUND AND PURPOSE: Carotid webs are intraluminal shelf-like filling defects at the carotid bulb with recently recognized implications in patients with recurrent ischemic stroke. We sought to determine whether carotid webs are an under-recognized cause of "cryptogenic" ischemic stroke and to estimate their prevalence in the general population. MATERIALS AND METHODS: A retrospective review of neck CTA studies in young patients with cryptogenic stroke over the past 6 years (n = 33) was performed to determine the prevalence of carotid webs compared with a control group of patients who received neck CTA studies for reasons other than ischemic stroke (n = 63). RESULTS: The prevalence of carotid webs in the cryptogenic stroke population was 21.2% (95% CI, 8.9%-38.9%). Patients with symptomatic carotid webs had a mean age of 38.9 years (range, 30-48 years) and were mostly African American (86%) and women (86%). In contrast, only 1.6% (95% CI, 0%-8.5%) of patients in the control group demonstrated a web. Our findings demonstrate a statistically significant association between carotid webs and ischemic stroke (OR = 16.7; 95% CI, 2.78-320.3; P = .01). CONCLUSIONS: Carotid webs exhibit a strong association with ischemic stroke, and their presence should be suspected in patients lacking other risk factors, particularly African American women.

Expression of N-methyl-D-aspartate glutamate receptor subunits in the prefrontal cortex of the rat.

The laminar distribution and cellular levels of expression of mRNAs encoding N-methyl-D-aspartate receptor subunits (NMDAR1, NMDAR2A-D and the alternatively spliced isoforms of NMDAR1) were examined in prefrontal cortex of rat by in situ hybridization using film and emulsion autoradiography. Film autoradiograms demonstrated a distinctive laminar distribution of hybridization signals for each of the probes recognizing NMDAR1, NMDAR2A, and NMDAR2B messenger RNA; hybridization with probes for NMDAR2C and NMDAR2D resulted in scattered signals without laminar organization. Grain counting disclosed that neurons in layer V displayed the highest and neurons in layer IV the lowest absolute number of grains for all probes examined. Correction for cell size demonstrated statistically significant differences in cellular labelling density of up to 50% across neurons in different cortical layers. The cellular density profiles across cortical laminae differed between probes. Hybridization with a probe recognizing all isoforms of NMDAR1 resulted in significantly lower densities of cellular labelling in neurons of layer IV than of layers II/III, V and VI. Cellular labelling densities following hybridization with probes recognizing alternatively spliced segments of NMDAR1 were examined. Densities were low in neurons of the upper cortical layers II/III and IV using probes for the messenger RNA encoding the amino terminal insert, NMDAR11XX and the second carboxy terminal deletion, NMDAR1XX1; hybridization with a probe for the messenger RNA encoding the first carboxy terminal deletion, NMDAR1X1X, resulted in low cellular signal densities in neurons of layers IV and VIb. NMDAR2A messenger RNA expression was of relatively uniform intensity in neurons of layers II-V but significantly lower in neurons of the inner part of layer VI. NMDAR2B expression was most dense in layer II neurons. These data indicate that neurons in different cortical laminae express distinct N-methyl-D-aspartate receptor subunit messenger RNA phenotypes. In addition, the observed differences in density of N-methyl-D-aspartate receptor subunit messenger RNA expression suggest that cortical laminae differ in the relative contribution of N-methyl-D-aspartate receptors to their excitatory responses.

Stroke treatment: beyond the three-hour window and in the pregnant patient.

For acute stroke patients who arrive at the hospital within 3 h of symptom onset, the focus of care involves screening for eligibility to receive intravenous tissue plasminogen activator. The publication of the National Institute of Neurological Disorders and Stroke recombinant tissue-type plasminogen activator (tPA, or alteplase) study in 1995 (Marler, J.R. 1995, New England Journal of Medicine333: 1581-1587) spurred protocol changes, which continue to evolve, throughout the health care system in an effort to streamline the patient through the Emergency Medical System. The need to expedite patient evaluation involving emergency department, laboratory, radiology, and clinical neurology testing is clear and has been a focus of many stroke centers. For some patients, intravenous thrombolysis within 3 h has a dramatic effect on outcome. However, that is not the only course of action for acute stroke patients. This article will review some of the effective treatments for stroke patients beyond the first 3 h of their care.

Information: what do consumers want to know?

National statistics indicate the potential demand for health care information will become an increasingly important area of attention in the years ahead. Consumers currently focus on such factors as reputation, accessibility, and cost when making health care decisions. Future consumers will be concerned with the interests, experience, satisfaction, and outcomes of health professionals, facilities, and plans. Current public dissemination efforts will create additional demand for more and better health care information.

Crossmatch compatible blood for patients with anti-P1.

Anti-P1 is a cold-reactive antibody often found in the serum of P2 individuals. For the past two years our reference laboratory has encouraged the use of crossmatch compatible blood for patients with Anti-P1 rather than the use of reagent-typed P1 negative units. The authors recently surveyed those hospitals that referred patient samples with anti-P1 to determine the safety of blood selected in this manner. Nineteen patients received 53 units without incident using this procedure. This report is a summary of the authors' findings.

The lac operator-repressor system is functional in the mouse.

We report the successful transfer of a fully functional lac operator-repressor gene regulatory system to the mouse. The key component is a lac repressor transgene that resembles a typical mammalian gene both in codon usage and structure and expresses functional levels of repressor protein in the animal. We used the repressor to regulate the expression of a mammalian reporter gene consisting of the tyrosinase promoter embedded with three short lac operator sequences and the tyrosinase coding sequence. Pigmentation of the mouse was controlled by the interaction of the lac repressor with the regulatable Tyrosinase transgene in a manner that was fully reversible by the lactose analog IPTG. Direct control of mammalian promoters by the lac repressor provides tight, reversible regulation, predictable levels of de-repressed expression, and the promise of reversible control of the endogenous genome.