Case of "slow" stroke from carotid artery occlusion treated by delayed but cautious endovascular intervention.

In a challenging case of carotid occlusion with slowly evolving stroke, we used brain imaging to facilitate endovascular revascularization resulting in the relief of the patient's symptoms. Patients with carotid occlusion and continued neurological worsening or fluctuations present enormous treatment challenges. These patients may present "slow" strokes with subacute infarcts that present significant challenges and risks during attempts at revascularization of the occluded artery. We present such a case in which we used multimodal imaging techniques, including MR-perfusion, to facilitate endovascular revascularization. Our approach of delayed but cautious intra-arterial thrombolytic therapy, guided by brain imaging, and followed by stent placement across the residual stenosis, enabled revascularization of the occluded artery without overt in-hospital complications.

Intracellular chemical messengers and neuronal function: Two examples

Two distinct classes of neurons have been examined in the nervous system of Aplysia. The membrane properties of these neurons are regulated by intracellular signalling molecules in both a short-term and a long-term fashion.^ The role of the phosphatidylinositol cycle in the control of neuronal properties was studied in a class of bursting pacemaker cells, the left upper-quadrant bursting neurons (cells L2, L3, L4, and L6) of the abdominal ganglion of Aplysia. These cells display a regular burst-firing pattern that is controlled by cyclic changes of intracellular Ca$\sp{2+}$ that occur during the bursting rhythm. The characteristic bursting pattern of these neurons occurs within a range of membrane potentials ($-35$ to $-50$ mV) called the pacemaker range. Intracellular pressure injection of inositol 1,4,5-trisphosphate (IP$\sb3$) altered the bursting rhythm of the bursting cells. Injection of IP$\sb3$ induced a brief depolarization that was followed by a long-lasting (2-15 min) hyperpolarization. When cells were voltage-clamped at potentials within the pacemaker range, injection of IP$\sb3$ generally induced a biphasic response that had a total duration of 2-15 min. An initial inward shift in holding current (I$\sb{\rm in}$), which lasted 5-120 sec, was followed by a slow outward shift in holding current (I$\sb{\rm out}$). At membrane potentials more negative than $-40$ mV, I$\sb{\rm in}$ was associated with a small and relatively voltage-independent increase in membrane conductance. I$\sb{\rm in}$ was not blocked by bath application of TTX or Co$\sp{2+}$. Although I$\sb{\rm in}$ was activated by injection of IP$\sb3$, it was not blocked by iontophoretic injection of ethyleneglycol-bis-(beta-aminoethyl ether), N, N$\sp\prime$-tetraacetic acid (EGTA) sufficient to block the Ca$\sp{2+}$-activated inward tail current (I$\sb{\rm B}$).^ Long-term (lasting at least 24 hours) effects of adenylate cyclase activation were examined in a well characterized class of mechanosensory neurons in Aplysia. The injected cells were analyzed 24 hours later by two-electrode voltage-clamp techniques. We found that K$\sp+$ currents of these cells were reduced 24 hours after injection of cAMP. The currents that were reduced by cAMP were very similar to those found to be reduced 24 hours after behavioral sensitization. These results suggest that cAMP is part of the intracellular signal that induces long-term sensitization in Aplysia. (Abstract shortened with permission of author.) ^

Folklore, fad, and fashion: The concept of misconduct in science redefined

This study is an analytical investigation of the nature and implications of the current conceptions of scientific misconduct, arguing that the question of what constitutes misconduct in science is significantly more complex than what conventionally has been believed. Complicating the definitions of misconduct are the differences between professional science and non-scientific professions, in their respective norms of what constitutes valid knowledge, and what counts as appropriate and inappropriate practice. While institutionalized science claims that there is clear differentiation between its standards of validity and those of the non-scientific professions, this paper argues that, when it comes to misconduct, the perceived boundaries between the scientific and non-scientific professions are breached; the practice standards that science currently employs in self-policing misconduct have come to resemble the minimal juridical standards of practice that other professions employ. This study attempts, despite erosion of these traditional boundaries, to move from legalistic standards of scientific practice to intramural standards of practice, and in so doing, to hold scientific practice to a higher standard than ordinary public conduct. The result is a clearer understanding of scientific misconduct to aid those individual scientists who are required to make onerous determinations about the appropriateness of specific practices by their peers. ^

A descriptive study of the sociodemographic, health and developmental factors associated with slow learning in children from upper to middle social class families in Texas

"Slow Learners" is a term used to describe children with an IQ range of 70-89 on a standardized individual intelligence test (i.e. with a standard deviation of either 15 or 16). They have above retarded, but below average intelligence and potential to learn. If the factors associated with the etiology of slow learning in children can be identified, it may be possible to hypothesize causal relationships which can be tested by intervention studies specifically designed to prevent slow learning. If effective, these may ultimately reduce the incidence of school dropouts and their cost to society. To date, there is little information about variables which may be etiologically significant. In an attempt to identify such etiologic factors this study examines the sociodemographic characteristics, prenatal history (hypertension, smoking, infections, medication, vaginal bleeding, etc.), natal history (length of delivery, Apgar score, birth trauma, resuscitation, etc.), neonatal history (infections, seizures, head trauma, etc.), developmental history (health problems, developmental milestones and growth during infancy and early childhood), and family history (educational level of the parents, occupation, history of similar condition in the family, etc.) of a series of children defined as slow learners. The study is limited to children from middle to high socioeconomic families in order to exclude the possible confounding variable of low socioeconomic status, and because a descriptive study of this group has not been previously reported. ^

Predictors of HIV-1 slow progression among vertically infected children in Botswana

HIV-1 infected children display a highly variable rate of progression to AIDS. Data about reasons underlying the variable progression to AIDS among vertically-infected children is sparse, and the few studies that have examined this important question have almost exclusively been done in the developed world. This is despite the fact that Sub-Saharan Africa is home to over 90% of all HIV infected children around the world.^ The main objective of this study was to examine predictors of HIV-1 slow progression among vertically infected children in Botswana, using a case control design. Cases (slow progressors) and controls (rapid progressors) were drawn from medical records of HIV-1 infected children being followed up for routine care and treatment at the BBCCCOE between February 2003 and February 2011. Univariate and Multivariate Logistic Regression Analyses were performed to identify independent predictors of slow disease progression and control for confounding respectively. ^ The study population comprised of 152 cases and 201 controls with ages ranging from 6 months to 16 years at baseline. Low baseline HIV-1 RNA viral load was the strongest independent predictor of slow progression (adjusted OR = 5.52, 95% CI = 2.75-11.07; P <0.001). Other independent predictors of slow disease progression identified were: lack of history of PMTCT with single dose Nevirapine plus Zidovudine (adjusted OR = 4.45, 95% CI = 1.45-13.69; P = 0.009) and maternal vital status (alive) (adjusted OR = 2.46, 95% CI = 1.51-4.01; P < 0.00 ).^ The results of this study may help clinicians and policy-makers in resource-limited settings to identify, at baseline, which children are at highest risk of rapid progression to AIDS and thus prioritize them for immediate intervention with HAART and other measures that would mitigate disease progression. At the same time HAART may be delayed among children who are at lower risk of disease progression. This would enable the highly affected, yet impoverished, Sub-Saharan African countries to use their scarce resources more efficiently which may in turn ensure that their National Antiretroviral Therapy Programs become more sustainable. Delaying HAART among the low-risk children would also lower the occurrence of adverse drug reactions associated with antiretroviral drugs exposure.^ Keywords. Slow Progressors, Rapid Progressors, HIV-1, Predictors, Children, Vertical Transmission, Sub-Saharan Africa^