Biomedical subjects

C J Russo

Publications and source records attributed to C J Russo.

4 recordsLinked to original sources

PubMed2006

Cryptic striations in the upper mantle revealed by hafnium isotopes in southeast Indian ridge basalts.

The Earth's mantle is isotopically heterogeneous on length scales ranging from centimetres to more than 10(4) kilometres. This heterogeneity originates from partial melt extraction and plate tectonic recycling, whereas stirring during mantle convection tends to reduce it. Here we show that mid-ocean ridge basalts from 2,000 km along the southeast Indian ridge (SEIR) display a bimodal hafnium isotopic distribution. This bimodality reveals the presence of ancient compositional striations (streaks) in the Indian Ocean upper mantle. The number density of the streaks is described by a Poisson distribution, with an average thickness of approximately 40 km. Such a distribution is anticipated for a well-stirred upper mantle, in which heterogeneity is continually introduced by plate tectonic recycling, and redistributed by viscous stretching and convective refolding.

Journal Article↗

PubMed1997

Birthdate and cell marker analysis of scrambler: a novel mutation affecting cortical development with a reeler-like phenotype.

The reeler mutation in mice produces an especially well characterized disorder, with systematically abnormal migration of cerebral cortical neurons. The reeler gene encodes a large protein, termed Reelin, that in the cortex is synthesized and secreted exclusively in the Cajal-Retzius neurons of the cortical marginal zone (D'Arcangelo et al., 1995). In reeler mutant mice, loss of Reelin protein is associated with a systematic loss of the normal, "inside-out" sequence of neurogenesis in the cortex: neurons are formed in the normal sequence but become localized in the cortex in a somewhat inverted, although relatively disorganized "outside-in" pattern. Here we show that the scrambler mutant mouse exhibits a loss of lamination in the cortex and hippocampus that is indistinguishable from that seen in the reeler mouse. We use BrdU birthdating studies to show that scrambler cortex shows a somewhat inverted "outside-in" sequence of birthdates for cortical neurons that is similar to that previously described in reeler cortex. Finally, we perform staining with the CR-50 monoclonal antibody (Ogawa et al., 1995), which recognizes the Reelin protein (D'Arcangelo et al., 1997). We show that Reelin immunoreactivity is present in the scrambler cortex in a normal pattern, suggesting that Reelin is synthesized and released normally. Our data suggest that scrambler is a mutation in the same gene pathway as the reeler gene (Relnrl) and is most likely downstream of Relnrl.

Animals↗

PubMed1997

Aberrant splicing of a mouse disabled homolog, mdab1, in the scrambler mouse.

Although accurate long-distance neuronal migration is a cardinal feature of cerebral cortical development, little is known about control of this migration. The scrambler (scm) mouse shows abnormal cortical lamination that is indistinguishable from reeler. Genetic and physical mapping of scm identified yeast artificial chromosomes containing an exon of mdab1, a homolog of Drosophila disabled, which encodes a phosphoprotein that binds nonreceptor tyrosine kinases. mdab1 transcripts showed abnormal splicing in scm homozygotes, with 1.5 kb of intracisternal A particle retrotransposon sequence inserted into the mdab1 coding region in antisense orientation, producing a mutated and truncated predicted protein. Therefore, mdab1 is most likely the scm gene, thus implicating nonreceptor tyrosine kinases in neuronal migration and lamination in developing cerebral cortex.

Animals↗

PubMed1994

Patient preferences for stroke outcomes.

BACKGROUND AND PURPOSE: In clinical trials stroke is reported as a major morbid outcome, but the impact of stroke on patients is not directly assessed. This study examines patient preferences for different outcomes of stroke, including death. METHODS: We presented patients with written case scenarios of stroke outcomes. The scenarios represented four categories of stroke severity (mild, moderate, severe, and fatal), and for nonfatal strokes the scenarios described motor, language, and cognitive deficits. Patients reported values for each of the 10 stroke scenarios using a rank-and-scale method over a 100-point range, with 100 representing perfect health and 0 corresponding to the worst possible health state. RESULTS: One hundred seventeen of 209 consecutive patients at risk for stroke participated in this study. Severe strokes were uniformly rated as having low preference weights (mean +/- SD [median]: 3 +/- 4 [1] for disabling hemiplegia, 8 +/- 9 [5] for confusion, and 15 +/- 14 [10] for global aphasia), and severe motor impairment (a disabling hemiplegia) was rated as significantly worse than death. Even mild deficits resulted in substantial loss to patients (54 +/- 21 [55] for dysarthria and 53 +/- 21 [50] for mild anomia). CONCLUSIONS: Strokes may result in a wide variety of post-stroke consequences for patients. Severe strokes may be viewed by patients as tantamount to or worse than death. Even mild strokes may cause significant declines in patient preferences for health states. These data are useful in interpreting studies that report stroke and death, in designing new studies that measure stroke in at-risk populations, and in helping patients reach treatment decisions about therapies designed to prevent strokes.

Aged↗