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Biomedical subjects

Jennifer Moore

Publications and source records attributed to Jennifer Moore.

8 recordsLinked to original sources

Excitatory synaptic potentials in spastic human motoneurons have a short rise-time.

This study assessed whether changes in size or time-course of excitatory postsynaptic potentials (EPSPs) in motoneurons innervating spastic muscle could induce a greater synaptic response, and thereby contribute to reflex hyperexcitability. We compared motor unit (MU) firing patterns elicited by tendon taps applied to both spastic and contralateral (nonspastic) biceps brachii muscle in hemiparetic stroke subjects. Based on recordings of 115 MUs, significantly shortened EPSP rise times were present on the spastic side, but with no significant differences in estimated EPSP amplitude. These changes may contribute to hyperexcitable reflex responses at short latency, but the EPSP amplitude changes appear insufficient to account for global differences in reflex excitability.

Excitatory Postsynaptic Potentials↗

The effect of Pencan needle orientation on spinal anesthesia outcomes.

Slow resolution of block and incidence of side effects deter many practitioners from choosing spinal anesthesia for out-patient surgical procedures. Some studies suggest that controlling bevel or side port orientation of a spinal needle during anesthetic injection can affect occurrence of side effects and time to block resolution. The objective of this study was to determine the effects of varying Pencan spinal needle (B-Braun, Bethlehem, Pa) side port orientations on duration of block and incidence of side effects in groups of patients receiving spinal anesthesia. We randomized 87 subjects scheduled for spinal anesthesia to receive a spinal anesthesia injection using a cephalad, lateral, or caudad side port orientation. Onset, duration, block height, incidence of side effects, and analgesic requirements were among the variables measured. No difference in onset, duration, or analgesic requirements was noted among groups. Differences were noted in time to discharge from the hospital (P = .027) and time to first voiding (P = .023) in the lateral compared with the cephalad and caudad orientation groups. Patients in whom the lateral needle side port orientation was used for injection were discharged earlier and had fewer side effects. This could translate into significant savings, financially and in terms of staff requirements.

Adjuvants, Anesthesia↗

Role of RUNX1 in adult hematopoiesis: analysis of RUNX1-IRES-GFP knock-in mice reveals differential lineage expression.

The Runx1/core binding factor-beta (CBFbeta) transcriptional complex is required for the establishment of hematopoiesis during development. Despite its critical role during development, a detailed analysis of Runx1 expression within specific lineages and developmental stages of the adult hematopoietic system is lacking. To address this, we have developed a Runx1-green fluorescent protein (GFP) knock-in mouse. We show that Runx1 is expressed in several hematopoietic lineages, including myeloid, B-lymphoid, and T-lymphoid cells. By contrast, Runx1 is weakly expressed in early erythroid cells, and its expression is rapidly extinguished during later stages of erythropoiesis. Runx1 expression is induced during early B-cell development and is expressed at a uniform level during all subsequent stages of B-cell development. Within the thymus, Runx1 is expressed at the highest level in CD4-CD8- double-negative thymocytes. In peripheral T cells, Runx1 is differentially expressed, with CD4+ T cells expressing 2- to 3-fold higher levels of Runx1 than CD8+ cells. Taken together, these findings indicate that although widely expressed in the hematopoietic system, the expression of Runx1 is regulated in a cell type- and maturation stage-specific manner. In addition, the Runx1-IRES-GFP knock-in mouse strain should prove valuable for investigation of Runx1 function in adult hematopoiesis.

Adult↗

Is war necessary?

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Attitude of Health Personnel↗

Clinicopathologic analysis of follicular lymphoma occurring in children.

Follicular lymphoma is a rare lymphoid malignancy in pediatric patients and consequently remains poorly characterized, particularly with respect to its immunophenotype and molecular pathogenesis. A total of 23 pediatric patients with follicular lymphoma were identified, with a median age of 11 years and a male-to-female ratio of 2.3:1. Of the 19 patients for whom presenting clinical features were available, 15 patients had stage I, 1 had stage II, and 3 had stage III or IV disease. All tumors had a follicular architecture, and 74% of cases had grade 2 or 3 histologic features. All patients expressed CD20 and bcl-6, and 80% were positive for CD10. Bcl-2 expression was detected in only 5 of 16 cases. Consistent with this finding, bcl-2 gene rearrangements were detected in only 2 of 16 cases by polymerase chain reaction. These patients were treated primarily with cyclophosphamide, doxorubicin, vincristine, and prednisone-based chemotherapy; 4 patients also received involved-field irradiation. Of the 13 patients with available clinical follow-up, all but 2 achieved durable clinical remission. Importantly, all 4 patients with tumors diffusely positive for bcl-2 either presented with stage III/IV disease or had disease refractory to therapy, whereas patients with bcl-2-negative tumors uniformly had stage I disease, achieved complete remission, and experienced no relapses. These findings indicate that, in contrast to adult follicular lymphomas, dysregulated bcl-2 expression does not play a significant pathogenetic role in most pediatric follicular lymphomas. However, bcl-2 expression in pediatric follicular lymphoma identifies a subset of patients in whom disease is often disseminated at clinical presentation and is more refractory to combination chemotherapy.

Adolescent↗

Characterization of mitotic neurons derived from adult rat hypothalamus and brain stem.

Embryonic or neonatal rat neurons retain plasticity and are readily grown in tissue culture, but neurons of the adult brain were thought to be terminally differentiated and therefore difficult to culture. Recent studies, however, suggest that it may be possible to culture differentiated neurons from the hippocampus of adult rats. We modified these procedures to grow differentiated neurons from adult rat hypothalamus and brain stem. At day 7 in tissue culture and beyond, the predominant cell types in hypothalamic and brain stem cultures had a stellate morphology and could be subdivided into two distinct groups, one of which stained with antibodies to the immature neuron marker alpha-internexin, while the other stained with the astrocyte marker GFAP. The alpha-internexin positive cells were mitotic and grew to form a characteristic two-dimensional cellular network. These alpha-internexin positive cells coimmunostained for the neuronal markers MAP2, type III beta-tubulin, and tau, and also bound tetanus toxin, but were negative for the oligodendrocyte marker GalC and also for the neurofilament triplet proteins NF-L, NF-M, and NF-H, markers of more mature neurons. Patch-clamp analysis of these alpha-internexin positive cells revealed small Ca(2+) currents with a peak current of -0.5 +/- 0.1 pA/pF at a membrane potential of -20 mV (n = 5) and half-maximal activation at -30 mV (n = 5). Na(+) currents with a peak current density of -154.5 +/- 49.8 pA/pF at a membrane potential of -15 mV (n = 5) were also present. We also show that these cells can be frozen and regrown in tissue culture and that they can be efficiently infected by viral vectors. These cells therefore have the immunological and electrophysiological properties of immature mitotic neurons and should be useful in a variety of future studies of neuronal differentiation and function.

Age Factors↗